Green Chemistry: and UN Sustainability Development Goals 9783110723960, 9783110723861

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Mark Anthony Benvenuto, Steven Kosmas (Eds.) Green Chemistry Green Chemical Processing

Green Chemical Processing

Edited by Mark Anthony Benvenuto

Volume 9

Green Chemistry

and UN Sustainability Development Goals Edited by Mark Anthony Benvenuto and Steven Kosmas

Editors Prof. Dr. Mark Anthony Benvenuto Department of Chemistry and Biochemistry University of Detroit Mercy 4001 W. McNichols Rd. Detroit, MI 48221-3038 USA [email protected] Steven Kosmas Mercy High School Farmington Hills, Michigan USA [email protected]

ISBN 978-3-11-072386-1 e-ISBN (PDF) 978-3-11-072396-0 e-ISBN (EPUB) 978-3-11-072404-2 ISSN 2366-2115 Library of Congress Control Number: 2022938179 Bibliographic information published by the Deutsche Nationalbibliothek The Deutsche Nationalbibliothek lists this publication in the Deutsche Nationalbibliografie; detailed bibliographic data are available on the internet at http://dnb.dnb.de. © 2022 Walter de Gruyter GmbH, Berlin/Boston Cover image: scyther5/iStock/Thinkstock Typesetting: Integra Software Services Pvt. Ltd. Printing and binding: CPI books GmbH, Leck www.degruyter.com

About the series Green Chemical Processing is a continuing series of volumes composed of refereed chapters, with upcoming volumes having submission dates of 15 June and 15 December each year. All areas of green chemistry, pending as well as established, are considered and welcome. If you are interested in contributing a chapter, please contact series editor Mark Benvenuto, of the University of Detroit Mercy, at [email protected] concerning the appropriateness of your topic. We are interested in any and all new ideas that examine any of the 12 principles of green chemistry. For more information on all previous and upcoming volumes of Green Chemical Processing, see https://www.degruyter.com/view/serial/GRCP-B

https://doi.org/10.1515/9783110723960-202

Contents About the series Author list

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IX

Steven Kosmas and Mark Anthony Benvenuto 1 Introduction 1 Liza Abraham 2 Applications of green chemistry in laboratory experiments and undergraduate research 3 Larry Kolopajlo 3 The UN sustainable development goals and nanochemistry: a critical review 45 Andrea Ashley-Oyewole 4 Green chemistry and the UN SDGs

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Sahil D. Patel and Cameron C. Weber 5 Alternative solvents and the UN sustainable development goals

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Mahin A. Zaman and Anne E. Marteel-Parrish 6 A sustainable development approach to promoting water security in Eritrea 129 Iris S. Teixeira, Thais R. Souza, Humberto M. S. Milagre and Cintia D. F. Milagre 7 The role of biocatalysis in green and sustainable chemistry Michal Tomasz Ruprecht 8 The climate education clock Scott Milam 9 LOL diagrams

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175

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Ashley M. Smith and Edward P. Zovinka 10 Green chemistry teaching and research at a small, Catholic university Index

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Author list Liza Abraham Department of Chemistry Ambrose University 150 Ambrose Circle SW Calgary, AB Canada T3H 0L5 [email protected]

Anne E. Marteel-Parrish Department of Chemistry Washington College 300 Washington Avenue Chestertown, MD 21620 USA [email protected]

Larry Kolopajlo [email protected] Chemistry Department Eastern Michigan University Ypsilanti, MI USA [email protected]

Iris S. Teixeira Institute of Chemistry São Paulo State University (Unesp) Araraquara – SP Brazil

Andrea Ashley-Oyewole Prairie View A&M University Prairie View, TX USA [email protected] Sahil D. Patel University of Auckland Auckland 1010 New Zealand Cameron C. Weber University of Auckland Auckland 1010 New Zealand [email protected] Mahin A. Zaman Department of Chemistry Washington College 300 Washington Avenue Chestertown, MD 21620 USA

https://doi.org/10.1515/9783110723960-204

Thais R. Souza Institute of Chemistry São Paulo State University (Unesp) Araraquara – SP Brazil Humberto M. S. Milagre Institute of Chemistry São Paulo State University (Unesp) Araraquara – SP Brazil Cintia D. F. Milagre Institute of Chemistry São Paulo State University (Unesp) Araraquara – SP Brazil [email protected] Michal T. Ruprecht Department of Molecular, Cellular, and Developmental Biology University of Michigan Ann Arbor, MI 48109 USA [email protected]

X

Author list

Scott Milam Plymouth-Canton Educational Park Canton, MI 48187 USA [email protected] Ashley M. Smith Department of Chemistry Saint Francis University Loretto

PA 15940-0600 USA [email protected] Edward P. Zovinka Department of Chemistry Saint Francis University Loretto PA 15940-0600 USA

Steven Kosmas and Mark Anthony Benvenuto

1 Introduction The UN sustainable goals, bringing them to our students and others The United Nations (UN) has defined a series of sustainable goals, shown in Table 1.1, which can also be downloaded at: sdgs.un.org/goals. With their formulation and development, these are now discussed and used with increasing frequency in high schools, community colleges, and university-level classes. The aim of teachers in utilizing them is often to implant in students – the next generation – ways to think that will keep our planet from harm and degradation. Table 1.1: UN sustainable development goals. No.

Goal



No poverty



Zero hunger

Production of fertilizers and food crops



Good health and well-being

Medicinal chemistry



Quality education



Gender equality



Clean water and sanitation

Purification technologies



Affordable and clean energy

Green means of producing energy



Decent work and economic growth



Industry, innovation, and infrastructure



Reduced inequality



Sustainable cities and communities

Urban planning, materials use



Responsible consumption and production

Minimized use and major recycling



Climate action

Understanding of greenhouse gases



Life below water

Natural chemical processes



Life on land

Natural chemical processes



Peace, justice, and strong institutions



Partnerships for the goals

https://doi.org/10.1515/9783110723960-001

Connections to science/chemistry education

Energy production and use

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Gathering a series of chapters that show how faculty use these goals, and how faculty get students engaged in the green chemistry related to them, is the focus of this volume. We are aware that we have not enlisted an author to speak on each of the goals but also know that some are more easily incorporated into the classroom than are others. We offer this volume as a means of furthering the discussion and raising the awareness of green chemistry and green processes among this generation of students, indeed, among all students in the K-16 range. They will, after all, become the citizens and leaders of the future. They will have to deal with the problems created by 8 billion people or more living on the planet. We hope through educating them to give them the tools to do so in a sustainable way. We hope that what is in this volume can help teachers and students develop a deeper understanding of green chemistry using systems thinking. Using just one example seen in the table, water quality is vitally important. Most of us are concerned about toxic substances in our drinking water, but we do not often quantify the toxicity load or teratogenic load. Systems thinking is easily integrated into the UN SDGs (sustainable development goals), since complex systems – like those needed for large-scale water purification and distribution – can be examined from multiple perspectives, including the economics and logistics of processing saltwater. If a greener process does not appear economically feasible or scaling the process seems cost prohibitive, then using a systems thinking approach may lead to a different conclusion. Trying to combine the cost of educating people about sustainability, the economics of scaling a greener process, and the toxicity or shortcomings of the former process will lead students to develop better critical thinking skills and lead to a more informed citizenry. If the negative impacts of the toxins, or of any existing system, are quantified and the health-related costs are considered, then the process that appears to be not economically feasible from one point of view may be economically sustainable from a systems thinking point of view. In short, we hope these chapters provide good starting points for numerous discussions and educational points concerning the UN SDGs.

Liza Abraham

2 Applications of green chemistry in laboratory experiments and undergraduate research Abstract: This chapter covers a series of laboratory experiments developed to provide a practical integration of green and sustainable chemistry concepts into the secondyear organic chemistry laboratory. The chapter also offers an example of a successful undergraduate research project in chemistry that demonstrates how a green chemistry project can make research-based learning feasible even in institutions with limited resources. The five laboratory experiments are based on a single, secondary plant metabolite, cinnamaldehyde, and the sixth experiment revisiting the tie-dyeing processe through a bioinspired and safer alternative to nucleophilic aromatic substitution (SNAr) reactions. Cinnamon oil was obtained through hydrodistillation, and cinnamaldehyde was used to carry out a reduction reaction, an aldol reaction, and the Schiff base formation. Students can practice techniques such as thin-layer chromatography, column chromatography, recrystallization, and melting point along with UV, Fourier-transform infrared, and 1H-nuclear magnetic resonance spectroscopies through these experiments. Microscale practices were employed in each of the reactions, and microscale column chromatography was used for purifications. The fifth experiment was an antimicrobial activity assessment of cinnamon oil and the cinnamaldehyde derivatives obtained from the previous experiments. Along with an interdisciplinary component, students were exposed to sunscreen chemistry and were led to consider the many uses of each product obtained. In the sixth experiment (tie-dyeing experiment), the water-soluble reactive dye that replaces a conventional SNAr substrate does not require any heavy metals, toxic substances, or mordants but utilizes a much less toxic and safer sodium carbonate to generate the cellulosate nucleophile. This reaction generates no waste, and the end product, the tie-dyed T-shirt, is reusable and biodegradable. The undergraduate research project focuses on developing a bioinspired, environmentally friendly wound-care product derived from chitosan and two naturally occurring aldehydes, citronellal and cinnamaldehyde. In this project, the student researcher prepared two chitosan Schiff bases using citronellal and cinnamaldehyde and then characterized and evaluated these products’ antimicrobial properties. Keywords: undergraduate research, laboratory classes

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2.1 Introduction As global awareness of climate change and fossil fuel depletion has increased, so has the prominence of green chemistry [1, 2]. In 1998, Anastas and Warner published Green Chemistry, Theory, and Practice, where they introduced 12 principles of green chemistry that outline what would make a greener chemical, process, or product [3]. The American Chemical Society sees the field of green chemistry as the future of chemistry which is “open for innovation, new ideas, and revolutionary progress” [4]. The US Environmental Protection Agency defined green chemistry as “the design of chemical products and processes that reduce or eliminate the use or generation of hazardous substances” [5]. Green chemistry initiatives promote the use of alternate, sustainable, and safer alternatives [6–9] as the chemistry industry relies heavily on the use of petroleum-derived materials. The rising trend of green chemistry has had significant influences on chemistry education [10–15]. Various universities and programs have responded to the increasing need to promote green chemistry initiatives’ awareness and practice [16]. Many green chemistry initiatives in education have been implemented in various ways: green chemistry courses [17], chemistry courses that include green chemistry course components [18], green chemistry laboratories [19–26], and green chemistry in undergraduate research [27, 28]. Initiatives such as these have played an essential role in promoting green chemistry principles and practice in a new generation of chemists. Following the growing green chemistry trend, many educators have striven to make the introductory organic chemistry lab experiments more environmentally benign [29–40]. Systems thinking influences green chemistry approaches and has informed much of the progress made in green chemistry [41–45]. Systems thinking is an approach “for examining and addressing complex behaviors and phenomena from a more holistic perspective” [45]. Systems thinking encourages chemists to recognize chemistry as a system that can help make the subject more comprehensible and coherent, rather than appearing as a massive list of facts to be learned, so that teaching and learning are facilitated. Incorporating a systems thinking approach to chemistry education connects students to real-world contexts and acquire skills to tackle the various sustainability challenges. Efforts are in place to train the next generation of chemists to connect chemistry and the environment. (The learner develops thinking skills on a system scale and sees how systems interact and influence one another, facilitating understanding and solving complex, multidimensional problems.) Employing a systems thinking approach also improves student’s engagement and participation and allows them to learn in a more in-depth and conceptual way, creating more connections within their discipline [46]. Life cycle thinking further adds to a holistic approach by considering the specific technological solution at each stage of a particular material life cycle [47].

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Together, systems thinking and life cycle thinking pair together well to ensure that green chemistry practices are effective and efficient. As society has adopted sustainability, green chemistry practices have become more prevalent, and green chemistry in education has developed to match this movement. It has become prevalent to introduce and apply green chemistry principles in laboratory courses. The integration of green chemistry into a curriculum has the potential to enhance safety in the laboratory through its application of RAMP (recognize hazards, assess the risks of hazards, minimize the risk of hazards, and prepare for emergencies) instructional approaches to chemical safety and by informing students about hazards and risks [43]. Using less hazardous chemicals reduces hazardous waste, thereby reducing the chance of accidental exposure and the overall cost of laboratory teaching [35]. Integrating green chemistry into undergraduate settings is also essential because it enables students to gain experience and knowledge about environmental and sustainability topics. These are very valuable to students, especially for their future careers, as employers are increasingly looking for students who can integrate sustainability with a holistic view of chemistry related to other disciplines [2, 42, 48, 49].

2.2 Cinnamon oil: an alternate and inexpensive resource for green chemistry experiments in organic chemistry laboratory 2.2.1 Overview of experiments based on cinnamaldehyde/ cinnamon oil The experiments based on cinnamaldehyde/cinnamon oil were centered around educating the undergraduate students about green chemistry and practically incorporating green chemistry principles into their laboratory experience in a feasible way that matches the learning outcomes of common reactions in organic chemistry laboratories. The five laboratories are based upon the compound cinnamaldehyde. The first experiment in the series is the hydrodistillation of cinnamon to obtain cinnamon oil. The 1 H-NMR (nuclear magnetic resonance) showed that the cinnamon oil obtained was pure cinnamaldehyde (Figure 2.1). Thus, the cinnamon oil was used as the source of cinnamaldehyde in the following reduction reaction. Experiments 3 and 4 are a Schiff base (SB) formation followed by an aldol reaction. Lastly, an interdisciplinary component is included to measure each product’s antimicrobial properties from the prior experiments. These five experiments allow students to benefit from gaining exposure to green chemistry and practical hands-on opportunities to employ some of the practices and an interdisciplinary component that prompts them to recognize the interconnectedness and interdependence of chemistry with other disciplines. The students can also appreciate

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Liza Abraham

that the same experiments can be done using a plant metabolite rather than a petroleum-derived reactant/reagent. This laboratory series involves using cinnamaldehyde as an environmentally friendly, safer, and sustainable reactant to create a less toxic product while also reducing the operational costs of chemistry laboratories by using a nonpetroleum-derived starting material. Microscale practices are also used to minimize the production of hazardous waste. Altogether, these experiments allow students to benefit from hands-on experience with green and sustainable chemistry while achieving the same learning outcomes of a standard organic chemistry II laboratory course. Cinnamon Sticks O H Schiff’s Base

Reduction

OH

N

I

de

tiv Ac al bi ro

on ns

ic

lC at

tim

do io n

An

Al

ity

II

O

V

IV

Figure 2.1: Overview of experiments based on cinnamon oil.

2.2.2 Experimental design 2.2.2.1 Objectives The learning objectives remained the same as the organic chemistry II laboratories but added green chemistry and interdisciplinary study elements. The general laboratory objectives are as follows: – Practice laboratory techniques: distillation, recrystallization, melting point determination, liquid–liquid extraction, filtration, TLC (thin-layer chromatography), column chromatography, UV, FTIR (Fourier-transform infrared spectroscopy), and 1 H-NMR spectroscopy

2 Applications of green chemistry in undergraduate research

– – –

7

Safely and effectively perform synthetic organic reactions Apply green chemistry principles to hands-on laboratory experience Gain practical experience thinking about chemistry in an interdisciplinary context

Integrating green chemistry concepts into this series of laboratories was also intended to inspire students toward sustainable development and educate them to design and develop sustainable solutions. While not entirely separate from the general learning objectives, the project design objectives encompass more themes and specific concepts to address through the series of labs. 2.2.2.2 Project design objectives –

– – – – – –

Use cinnamon oil as a safer, renewable resource to carry out nucleophilic addition to carbonyl compound reactions and C–C bond formation reaction utilizing enolate chemistry Emphasize laboratory safety Use an aldol product to demonstrate sunscreen chemistry Introduce the principle of drug discovery Connect chemistry with microbiology through a study of antimicrobial activity Reduce the production of hazardous waste Reduce the cost and storage of chemicals

2.2.3 Cinnamaldehyde This series of labs (Figure 2.1) was based upon the use of one particular green compound, cinnamaldehyde (Figure 2.3). The students began by using hydrodistillation to obtain a sample of cinnamon oil from cinnamon sticks. Cinnamaldehyde is the main component of cinnamon, and when using steam distillation, it comprises about 60–90% of cinnamon oil [50]. The 1H-NMR spectra obtained from student samples showed that the cinnamon oil obtained was pure cinnamaldehyde (Figure 2.2). Because the samples were pure, no purification was needed, and the cinnamon oil was used as cinnamaldehyde in the following experiment: reduction reaction of cinnamaldehyde using sodium borohydride and purification of cinnamyl alcohol using microscale column chromatography. Through the first experiment, students were not only able to gain practical experience of carrying out a hydrodistillation but also able to see and appreciate firsthand how a plant metabolite can be used as a substrate in organic chemical reactions. The hydrodistillation was carried out to include these benefits, and the obtained cinnamon oil was used in the reduction reaction. Instead of using cinnamon oil for the SB and aldol reactions, store-bought cinnamaldehyde was used. Both the SB and aldol reaction products involved recrystallization, which requires an appreciable amount of substrate

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Liza Abraham

to start with. For this reason, it was decided to use store-bought cinnamaldehyde, as it is also of plant origin. However, using self-distilled cinnamon oil could also be done to carry out each of the experiments in the laboratory series. It would be beneficial to convert the hydrodistillation into a 1 g scale and carry out all reactions with the cinnamon oil; this is the future plan for applications of this laboratory series.

Figure 2.2: 1H-NMR spectrum of cinnamon oil.

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O H Figure 2.3: Structure of cinnamaldehyde.

Cinnamaldehyde was chosen as the focus of this laboratory series because it is a plant-based chemical and has a favorable structure for multiple reactions taught in organic chemistry II classes. One of the most significant chapters covered in organic chemistry II is carbonyl chemistry, which includes nucleophilic addition to carbonyl compounds and enolate chemistry. A variety of nucleophilic addition to carbonyl compound reactions can be carried out on the aldehyde functional group, making it a suitable compound for alcohol reduction, SB reaction, and aldol reaction. The antimicrobial properties of cinnamaldehyde [51, 52] and its derivatives also provide the unique opportunity to incorporate an interdisciplinary component into the series of labs and for students to gain exposure to how green chemistry can be applied beyond the scope of chemistry. Each reaction and purification was performed at microscale to reduce the amount of chemicals used and waste produced, and the cinnamon sticks themselves were obtained from a local grocery store for an economical cost.

2.2.4 Isolation of a renewable starting material: hydrodistillation of cinnamon oil from cinnamon This experiment utilized hydrodistillation to isolate cinnamaldehyde from cinnamon. After the distillation process, students used TLC to check the purity of their samples. This experiment also revisited concepts from organic chemistry I, such as FTIR and 1H-NMR spectroscopies. The students collected the FTIR spectra themselves, and the 1H-NMR was run immediately after carrying out the hydrodistillation by the instructor using a benchtop NMR (Magritek Spinsolve). It was expected that the product would not be pure, and after an NMR was taken (Figure 2.2), the students compared cinnamaldehyde spectral data with the isolated cinnamon oil. They identified that the cinnamon oil was essentially pure cinnamaldehyde. Therefore, no purification was required, and the cinnamon oil obtained was used as a source of cinnamaldehyde in the following experiment. After completion of the hydrodistillation, the students were assigned to write a short research paper that involved exploring the 12 green chemistry principles, identifying which of them were being applied in this experiment, and explaining the basis for applying them. Students also had to become familiar with the principles involved in hydrodistillation and the reasoning for using this technique. In addition, students explored the composition of cinnamon oil and its medicinal properties. Through this assignment, students were given the opportunity to personally engage

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with the chemical concepts being applied as well as gain a better understanding of the importance of green chemistry and simple approaches to apply them in a laboratory setting.

2.2.5 Reduction of cinnamaldehyde using sodium borohydride and purification of cinnamyl alcohol using microscale column chromatography The reduction of carbonyl compounds is one of the fundamental transformations in organic synthesis. This laboratory focused on the use of cinnamaldehyde as a greener substitute for benzaldehyde, reducing waste through a microscale reaction, demonstrating atom economy, and carrying out microscale column chromatography. Sodium borohydride was used to reduce the cinnamaldehyde in cinnamon oil. Though sodium borohydride is not a green chemical, the reaction was carried out at a microscale to reduce the amount of waste produced, and the students set up the organic reaction at a 0.1 g scale. Microscale practices also reduced the cost of materials and the overall cost of the experiment. Instead of using methanol as the solvent for the reduction, ethanol was utilized as a less toxic substitute. The students used TLC to monitor the reaction progress and performed a workup to recover the product. This experiment also utilized FTIR and 1H-NMR spectroscopies. The students were introduced to microscale column chromatography using microcolumns and hexane as a solvent. Though a toxic chemical, hexane was required as an organic solvent for the microcolumn. Microscale column chromatography was used to reduce the amount of silica gel produced and released to the environment and the amount of hexane used. For this experiment, student research papers included a review of reduction reactions of carbonyl compounds and reducing agents such as NaBH4 and LiAlH4 and their selectivity in reduction. They also discussed solvents and protection/deprotection chemistry. This research paper also involved researching more about green chemistry, and they discussed purification by microscale chromatography. The product in this experiment was cinnamyl alcohol, which is valuable in perfumery for its odor and fixative properties and is a component of many flower compositions such as lilac, hyacinth, and lily of the valley [53]. In their research, students were also able to explore the properties and uses of cinnamyl alcohol.

2.2.6 Schiff base reaction of cinnamaldehyde with aniline in water SBs are known as important biologically active compounds with antibacterial [54], antifungal [55], anticancer [56], antituberculotic [57], herbicidal [58], anti-HIV [59],

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antimalarial [60], antiproliferative [61], antiviral [62], antipyretic [63], antioxidant, and anti-inflammatory [64] activities. An SB reaction was chosen to include in this laboratory series because it was expected that an SB product would demonstrate antimicrobial activity in the last experiment and would allow an excellent opportunity to connect chemistry with microbiology. It was also chosen because cinnamaldehyde is already known to have antimicrobial activity, and it would be interesting to see if there is a better activity when it is used to make an SB. An SB reaction also provided an excellent opportunity to apply green synthetic chemistry into the laboratory series. Typically, SB reactions are carried out in organic solvents, which are volatile and toxic and can be damaging to the environment. A literature survey revealed that cinnamaldehyde-derived SBs have been created using microwave radiation [65], and in no solvent conditions [66]. Rao et al. synthesized SBs of a variety of aromatic aldehydes in aqueous medium [67]. This reaction was used as our basis, but with slight modifications to the procedure. Using water as a solvent provided a greener process and safer reaction medium. The SB reaction was able to demonstrate not only a standard synthetic reaction using a green starting material but also in benign solvent and reaction conditions. Through this short reaction (15 min), students practiced setting up a reaction, TLC, and recrystallization as a simple purification. They also determined the melting point of the product and used 1H-NMR spectroscopy for characterization. However, instead of focusing merely on the chemical reaction, the students learned about the application areas surrounding SB formation. Students were able to explore the various properties and uses of SBs in their research papers.

2.2.7 Aldol reaction of cinnamaldehyde with acetone – a demonstration of synthesis of a sunscreen In this experiment, students had the opportunity to perform an aldol condensation and elimination reaction. After the reaction, they practiced recrystallization. The students also obtained 1H-NMR and UV spectra of the product as well as the melting point. This reaction’s greenness is mainly related to safety through using a safer solvent (only 2.0 M sodium hydroxide), atom economy of the reaction, use of cinnamaldehyde as a naturally occurring aldehyde, and less production of waste through microscale practices. The aldol experiment provided an opportunity to introduce one of the useful carbon–carbon bond-forming reactions in organic chemistry and introduce sunscreen chemistry, which gave students a real-life focus of chemistry outside of the laboratory. The instructor discussed how the aldol product (Figure 2.4) is a model of a UVA filter. The UV spectrum obtained (Figure 2.5) had a λmax of 374 nm. This opened the way to discuss organic chemical absorbers, UVA, and UVB filters and compare aldol products to cinnamates employed as UV filters in sunscreen. The

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O Figure 2.4: Aldol reaction product of cinnamaldehyde and acetone.

students were informed how, though the aldol product’s absorption indicates that it is a good UVA filter, it cannot necessarily be applied as a sunscreen. Other aspects such as toxicity and photostability must be studied, so the aldol product is only a model of a UVA filter. After class discussions, the students explored sunscreen chemistry more in their research papers. The students discussed sunscreen concepts and enolizable ahydrogen, cross-aldol reactions, and the importance of UV spectrum in characterizing the aldol product. This experiment gave students a glimpse of research in that they analyzed their product compared to current literature. The students had to discover the commonly used FDA-approved chemical filters with their absorption maximum and classify them as UVA or UVB filters (Table 2.1). After running the UV spectrum of their aldol product, the students could compare the maximum absorptions and identify the aldol product as a UVA filter. This experiment and the related discussions provided students with an opportunity to take part in an experiment that more closely resembles undergraduate research as it did not end when the experiment was finished, but rather, knowledge about the reaction was applied further into a current area of study.

Figure 2.5: UV spectrum of aldol product obtained from the reaction of cinnamaldehyde and acetone.

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Table 2.1: Commonly used FDA-approved chemical filters (wavelength values obtained from the Indian Journal of Dermatology [68]). Structure

λmax

Avobenzone

UVA  nm

Oxybenzone

UVB + short UVA  and  nm

Homosalate

UVB  nm

Octisalate

UVB  nm

Octocrylene

UVB + short UVA  nm

Octinoxate

UVB UV max =  nm

Aldol product

 nm

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2.2.8 Assessment of the antimicrobial activity of cinnamaldehyde and its derivatives – a drug discovery lab This experiment was used to provide students with an interdisciplinary laboratory experience by connecting chemistry with microbiology. It also introduced students to the principle of drug discovery, which was a useful application, especially for majoring students in biology. Similar to the aldol experiment, this interdisciplinary experiment gave students a taste of an experiment resembling an undergraduate research project in that their reaction derivatives were examined for antimicrobial properties. For the antimicrobial test, both gram-positive and gram-negative bacteria were used to determine the antimicrobial activity of pure cinnamaldehyde, cinnamon oil, and the derivatives obtained in the earlier experiments (cinnamyl alcohol, aldol product, and SB product). Staphylococcus aureus was used for the gram-positive type, and Escherichia coli was used as a gram-negative type. The antimicrobial activity against cinnamaldehyde was measured by the agar well diffusion method [69]. To evaluate the antimicrobial activity against each organism, zones of inhibition expressed in millimeters were measured using a ruler and then recorded for analysis. Based on the inhibition zone results (supporting information), it was found that the antibacterial activity of all of the test compounds is better against E. coli than against S. aureus. This suggests that these materials are more effective against gram-positive than gram-negative bacteria. Besides cinnamaldehyde, cinnamyl alcohol and cinnamon oil showed the best antibacterial activity while the SB had weak antimicrobial activity and the aldol product displayed very little activity. Cinnamon oil displayed the most antimicrobial activity against both E. coli and S. aureus at 22.45 mm and 22.13 mm, respectively (Figures 2.6 and 2.7).

Figure 2.6: Sample agar well diffusion method plate shown after E. coli bacterial growth. Wells containing DMSO, cinnamyl alcohol, cinnamon oil, aldol product, Schiff base, and cinnamaldehyde are shown.

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Figure 2.7: Sample agar diffusion method plate shown after S. aureus bacterial growth. Wells containing DMSO, cinnamyl alcohol, cinnamon oil, aldol product, Schiff base, and cinnamaldehyde are shown.

The antimicrobial activities of pure cinnamaldehyde and cinnamon oil were also evaluated against S. aureus and E. coli based on the minimum inhibitory concentration (MIC) assay to determine the lowest concentration at which no bacteria growth was observed. The MICs of cinnamaldehyde, cinnamyl alcohol, and cinnamon oil against S. aureus were 0.3 mg/mL, 0.6 mg/mL, and 0.3 mg/mL, respectively. The MICs against E. coli were 0.3 mg/mL, 0.3 mg/mL, and 0.3 mg/mL, respectively.

2.2.9 Experimentation and assessment This series of experiments has been carried out during three separate semesters (winter 2018, 2019, and 2020). In total, 52 students participated in carrying out these labs (23, 14, and 15, respectively). The students carried out each experiment with a partner. The students recorded the FTIR and UV spectra and melting points, and the instructors recorded the NMR spectra in the laboratory. Table 2.2 includes the average class yields and melting point ranges obtained from the experiments’ most current implementation. Student assessment was evaluated using pre-laboratory assignments (see text box 1 and supporting information) and the research by the abovementioned papers. The pre-laboratory assignments asked students to consider what aspects of the experiment in question were not green, encouraging them to appreciate the experiments’ green aspects while also recognizing where they are not so green. The students were provided a rubric for the research papers that outlined the important concepts specific to each experiment (see supporting information). The final exam also included questions relating to specific concepts from this series of experiments. These methods were used to guide students to engage with the relevant concepts

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Table 2.2: Average yields and melting point ranges for winter 2020 semester class. Experiment

Yield (after purification)

Melting point (when applicable)

1.

Isolation of a renewable starting material: hydrodistillation of cinnamon oil from cinnamon

. g

2.

Reduction of cinnamaldehyde using sodium borohydride and purification of cinnamyl alcohol using microscale chromatography

–%

3.

Schiff base reaction of cinnamaldehyde with aniline in water

–%

– °C

4.

Aldol reaction of cinnamaldehyde with acetone – a demonstration of synthesis of a sunscreen

–%

– °C

for each experiment. The pre-laboratories, research papers, and exam questions were used to assess student performance and observe whether the experiments effectively met the learning objectives of the laboratory series. The second assigned research paper included a short extra requirement that asked students to identify which part of the experiment was intellectually stimulating and how it increased their interest in learning chemistry. Though no formal survey was administered to assess student perspectives, the instructors found that the students enjoyed the experiments and the opportunity to see green chemistry in action through informal conversations. The students met the practical learning objectives by completing the five experiments, such as practicing techniques including distillation, recrystallization, melting point determination, liquid–liquid extraction, filtration, TLC, column chromatography, UV, FTIR, and 1H-NMR spectroscopy. Across the three semesters, this lab took place; all of the students completed these practical techniques. The students received a grading rubric for the research papers and were evaluated according to how well they explained the topics relevant to the paper (e.g., sunscreen chemistry) and if they demonstrated a thorough discussion. The three groups of students who completed the laboratory series achieved, on average, grades in a range from 75.6% to 79.8% (see Table 2.3). Because the research papers delve into the concepts related to green chemistry principles and specific topics in the learning objectives, such as drug discovery, these grades were used to measure students’ learning. Thus, the students were considered to have met the practical learning objectives and those relating to green chemistry principles and real-world/interdisciplinary concepts.

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Table 2.3: Mean grade percentage for student research papers – winter 2018, 2019, and 2020. Lab 

Lab 

Lab 

Lab 

Lab 



.

.

.

.

.



.

.

.

.

.



.

.

.

.

.

Average

.

.

.

.

.

2.3 A green nucleophilic aromatic substitution reaction

Figure 2.8: Overview of a tie-dye experiment, a green nucleophilic aromatic substitution reaction.

There have been reports of employing biobased materials as reactants and reagents in the undergraduate organic chemistry laboratory [70–80]. Nucleophilic aromatic substitution (SNAr) reactions are one of the fundamental reactions taught in organic chemistry [81]. Recently, Lipton reorganized the organic chemistry curriculum by grouping nucleophilic addition–elimination reactions of carbonyl and aromatic compounds together based on a mechanistic perspective. Several authors have explored the SNAr reaction while applying a biobased perspective. A discovery-based SNAr experiment in water was reported to introduce chemistry students to micellar catalysis, green chemistry, and systems thinking [82]. Latimer et al. compared microwave-induced organic reaction enhancement to more traditional synthetic procedures toward SNAr reaction [83]. Rizvi et al. determined the activation energy of

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SNAr on porphyrins [84]. Goodrich et al. employed SNAr reaction as one reaction in the synthesis of a fluorescent acridone [85]. It is well established that enhanced learning and retention occur through practical hands-on experience with real-life examples [86], making the tie-dye experiment (Figure 2.8) an ideal method for engaging students. Bonneau presents a discussion of the organic reactions taking place between cotton and Procion MX dyes [87]. By exploring the organic chemistry related to the dyeing process, she suggests tie-dyeing as an interesting and relevant activity to engage high school students. The tie-dyeing process has been effectively used for chemistry education. For example, Bopegedera designed a tie-dyeing activity for beginner chemistry students at high-school and college levels to introduce polymer chemistry [88]. Making use of a daily life example, such as dyeing, also incorporates a systems thinking approach [2, 42] to help students see how chemistry fits into a real-world and interdisciplinary context.

2.3.1 Introducing the experiment Traditionally, an SNAr reaction involves a nitro aryl halide as the substrate, a leaving group, and a nucleophile in a solvent such as N, N-dimethylformamide (DMF) (Figure 2.9). Even though aryl halides are generally inert to nucleophilic substitution, aryl halides that contain electron withdrawing groups such as a nitro group ortho or para to the halogen undergo SNAr. Variations of SNAr experiments have been developed for chemistry education in the past, each with a distinct value [89–91]. For example, Santos et al. developed a problem-solving and collaborative-learning approach to synthesizing aryl-substituted 2,4-dinitrophenylamines to facilitate higher retention and encourage students to interpret and draw conclusions from data themselves [92]. Avila et al. redesigned the synthesis of 2-ethylbenzoic acid into a fivestep microscale experiment [93]. Taber and Brannick report the nucleophilic addition of 4-methoxyphenol to 4-fluorobenzaldehyde in a single laboratory period [94]. This experiment is unique in that it can be carried out in a single step to generate a crystalline product; however, standard safety precautions must be observed when working with chemicals and irritants such as dimethyl sulfoxide, potassium carbonate, 4-fluorobenzaldehyde, and 4-methoxy phenol. In contrast, we suggest using the reaction between cellulose fibers and Procion MX dyes as a greener and safer alternative for demonstrating an SNAr reaction in the undergraduate laboratory.

Figure 2.9: Nucleophilic aromatic substitution reaction.

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Dichlorotriazine dyes are commercially known as Procion MX dyes and are also known as reactive fiber dyes. Procion MX dye molecules form permanent chemical bonds with the cellulose molecules on the cotton fabric in the dyeing process. The structure of Procion Red MX-8B, along with the dye’s reactive portion, is given in Figure 2.10. The “R” represents the chromophore part of the dye molecule with the water-soluble sulfonate groups. Nucleophilic substitution is facilitated by the electron withdrawing properties of the aromatic nitrogens and chlorine. This makes the dichlorotriazine ring the dye molecule portion that reacts with the cellulose nucleophile while the halogen acts as a leaving group. Thus, the aromatic, dichlorotriazine ring can serve as the substrate toward the SNAr reaction and is a suitable alternative to use an aryl halide in a typical SNAr reaction. In this experiment, the three dye molecules used are Procion Red MX-8B, Procion Acid Lemon MX-8G, and Procion Bright Turquoise MX-G (Reactive Blue 140).

Figure 2.10: Structure of Procion Red MX-8B and the reactive portion of the dye.

The nucleophile is generated from the cellulose molecules in the cotton fiber. Cellulose (Figure 2.11) is a linear homopolymer of glucose linked with β (1 → 4) glycosidic bonds between the repeating unit’s hydroxyl groups. OH OH

6 4

HO

O

5

1 3

2

HO O

O O

OH OH

Structure of Cellulose

n

Figure 2.11: Structure of cellulose.

The simple treatment of the cotton fabric with sodium carbonate generates the cellulosate nucleophile (Figure 2.12).

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Figure 2.12: The reaction of cellulose with sodium carbonate.

The SNAR reaction occurs when the newly generated nucleophile reacts with the Procion reactive dyes, as shown in Figure 2.13.

Figure 2.13: The dyeing chemical reaction of Procion dye with cellulosate nucleophile.

2.3.2 Experimental overview After learning about the SNAr in the classroom, students were able to apply a hands-on application of the concept. Each pair of students prepared 2.5 g each of Fuchsia Red, Lemon Yellow, and Turquoise in 75.0 mL water and transferred them into three squeeze bottles in the lab. The T-shirts were soaked for 30 min in Na2CO3 solution (45.0 g in 750.0 mL water). After squeezing out the water, they folded and tied their T-shirts with elastic bands in their pattern of interest, and dyes of their choice were applied on both sides. Students took their T-shirt home in a plastic bag and allowed it to cure for at least 4 h, but preferably 24 h for the brightest colors. The T-shirts were then rinsed under cold running water and machine washed. The experiment took 1–1½ h of the laboratory period. Experimental details can be found in the supporting information. Before beginning the experiment, students completed a pre-laboratory assignment (refer to supporting information), where they explored environmental and health issues related to Procion dye in wastewater effluent and solutions of how to remove it. Once the dyeing process was completed, the students spent the second half of the laboratory period designing feasible methods that can be used to remove Procion dye using the reagents they had discovered. The lab instructor guided students to consider using the adsorbents they had listed to remove the dye. Because it was readily available in the lab, the students decided to use activated charcoal in a

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trial experiment. They were able to get a colorless solution. Figures 2.14 and 2.15 show the dye solutions, dye solutions with activated charcoal, and the filtered dye solutions for both Procion Bright Turquoise MX-G (Reactive Blue 140) and Procion Magenta Red MX-8B. The next day, the students rinsed their T-shirts and then used their procedure to remove the dye before discharging the water.

Figure 2.14: Trial dye removal experiment for Procion Magenta Red MX-8B using activated charcoal.

Figure 2.15: Trial dye removal experiment for Procion Bright Turquoise MX-G (Reactive Blue 140) using activated charcoal.

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After the experiment, students were assigned to write a report on the activities they completed. This assignment required students to explore the 12 green chemistry principles and their applications in the current experiment, discuss the process of designing and carrying out an experimental procedure, and discuss the need for chemists to practice stewardship.

2.3.3 Discussion The use of dyes has a long history and constitutes an important component in our daily lives [95–99]. Reactive dyes undergo SNAr reaction with cellulose under alkaline conditions to form covalent bonds between the fibers and dye. This experiment and its subsequent activities were designed to: – use a green and sustainable alternative in an SNAr reaction, – engage student’s interest through a real-life example, – facilitate life cycle thinking in green chemistry, – empower students to evaluate research literature on environmental dimensions of dyeing chemistry critically, and – allow students to exercise stewardship through designing a simple experiment. This experiment allows students to gain practice experience of concepts they learned about in class while integrating green chemistry practices. Typically, SNAr reactions involve a nitro aryl halide as the substrate and a nucleophile in a solvent such as DMF. In this experiment, dye molecules are used instead of the aryl halide, and cotton is used as the nucleophile. Eight of the 12 green chemistry principles [3] were addressed in this experiment: – less hazardous chemical synthesis, – safer solvent, – designing safer chemicals, – renewable feedstocks, – design for degradation, – design for energy efficiency, – inherently safer process, and – atom economy. The toxicological properties of the dyes change after the dyeing process resulting in both a reusable and biodegradable product. In addition to this, the high wash fastness of the dyed fabric ensures that no dye is exposed to the skin of the person wearing the shirt. Hence, dyeing chemistry can be presented as an example of less hazardous chemical synthesis than conventional SNAr reactions.

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Water is used as the reaction medium, and no hazardous solvents are involved in the dyeing process. Water is also used to wash and prepare the fabric before dyeing and clean and rinse the fabric afterward. No organic solvent is involved in this experiment, and only water, the safest solvent, is utilized in the dyeing process. An aqueous solution of sodium carbonate, a safer reagent, is used to prepare the nucleophile on the fabric for dyeing. The dyes contain no heavy metals or other known toxic substances and do not need mordants. These features utilize the green chemistry concept of designing safer chemicals. The nucleophile, cellulose, is generated from a renewable feedstock, and it is the most abundantly available biopolymer on the Earth, encompassing about 33% of all plant matter [100, 101]. The end product is reusable and environmentally friendly, accounting for the design of degradation. There was no separation or purification involved in the chemical reaction, differing from typical organic reactions that require extractions, chromatography, or recrystallization. The design principle for energy efficiency can also be applied here as the dyeing happens at room temperature. The whole lab process was inherently safe. Most of the dye becomes fixed into the T-shirt, though parts of it were rinsed off in the water. Students also came up with a method of extracting the unused dye leaving the water clean and safe to discharge into wastewater effluents. The principle of the atom economy can also be applied here because there is only a single product. In reviewing the green aspects of this reaction, students can see that 9 of the 12 principles of green chemistry have been addressed. The students were required to learn about green chemistry principles and include descriptions in their lab report of how they were applied in the experiment. This allowed them to learn about green chemistry as a discipline and simple ways to apply it in a typical reaction. Tie-dyeing is an enjoyable and tangible activity to engage students, therefore, providing an optimal opportunity to relate chemistry to daily life. This aspect of the experiment helps to draw in the interest of students while also helping them move away from a merely theoretical or abstract understanding of chemistry to grasp a view of chemistry in their daily lives. Because most students are already familiar with tie-dyeing, this experiment provides an optimal opportunity to connect class content to a laboratory experiment. The whole dyeing process is straightforward. It does not require any harsh chemicals, and the product is biodegradable. However, because the dye can react with hydroxide ion and the cellulosate anions, about 20% of the dye molecule end up unfixed on the fiber, and the unbound dye is washed off after the dyeing process [102]. The water used in rinsing is usually discharged into wastewater effluents and can cause environmental issues. The pre-laboratory assignment addressed this issue and asked students to research the environmental and health impacts associated with the dye. The students also had to research current literature to discover viable solutions and different chemicals that could be used to remove dye from the

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waters. Instead of throwing out the rinse water with the dyes as waste, they designed and used a procedure to mitigate the negative environmental impact. Another benefit of this experiment is that students are able to make use of the end product and keep their tie-dye shirts. As such, this experiment allows students to consider the life cycle of materials, including how they are transformed, used, and what happens at the end of their life spans. This kind of stewardship in an organic laboratory experiment is also a good opportunity for students to consider a systems thinking approach. Though tie-dyeing is not a novel experiment, when used in this context, it can allow students to evaluate dyeing chemistry, explore current literature, and design a simple procedure, all while tying together their knowledge of chemistry with the environment. This green SNAr experiment was carried out with a second-year organic chemistry class in the winter 2020 semester. Once the tie-dyeing was complete, the students engaged well with one another in their groups to find a solution to removing excess dye from the water. After the laboratory period, the students were able to take their shirts home and wear them. In their laboratory reports, the students also included a short paragraph of their overall impression of the experiment. The students had positive comments about the tie-dye activity and expressed that it was an engaging way to apply their knowledge about SNAr reactions from the classroom. Overall, the students commented that their knowledge of green chemistry principles increased from this laboratory experiment.

2.4 Motivating and supporting undergraduate research through green chemistry Instructors and institutions have long understood the value of undergraduate research in increasing the quality of student learning. Science instructors have often led the way in calling for and implementing these strategies. In the 1990s, the National Science Foundation and National Research Council promoted research-based learning as the gold standard in undergraduate science education [103, 104]. The Boyer Commission, the Higher Education Academy, and the Association of American Colleges and Universities all followed suit over the next decade, recommending that all undergraduate students experience learning through research and inquiry [105–107]. These organizations – and many other researchers – share a conviction that undergraduate research improves student learning by stimulating students’ curiosity and encouraging them to think independently. Indeed, these projects do stimulate and engage students. In a 3-year study, Seymour et al. found that students were overwhelmingly positive about research-based learning experiences [108]. Numerous organizations have shared models and resources for undergraduate research, yet research-based learning programs are often difficult to establish. The

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Council on Undergraduate Research (CUR) offers five strategies: (1) make research a necessary part of the undergraduate curriculum; (2) track the outcomes of undergraduate research programs; (3) prioritize diversity and inclusion among undergraduate researchers and faculty mentors; (4) develop partnerships with businesses, nonprofits, and other postsecondary institutions to create opportunities for research-based learning; and (5) create options for undergraduate research in international contexts [109]. In chemistry specifically, the ACS Symposium Series has published two books of best practices for supporting and expanding undergraduate research in chemistry [110, 111]. However, undergraduate research programs are often costly and timeconsuming. For this reason, at smaller educational institutions, research-based learning can become an underutilized pedagogical tool. To offer a viable undergraduate research program at this institution, instructors must develop research plans that do not require large expenditures or extensive equipment. For a small institution, undergraduate research in green chemistry provides a compelling solution: students and faculty can both benefit, and the costs to the institution are minimal. By participating in an independent research project, students can further develop their green chemistry interests and meaningfully contribute to a sustainable future for the planet. They can also deepen their knowledge by intentionally designing an experiment that follows the principles of green chemistry. Additionally, through these projects, students can gain valuable experience in assessing the impact of hazardous chemicals on environmental health – an experience that is valuable for future careers and research. By offering research-based learning in green chemistry, institutions can offer their students all of these benefits, even with minimal funding and laboratory equipment. A description of one specific project follows as an example of how topics in green chemistry can help to create possibilities for undergraduate research, even when resources are limited.

2.4.1 Undergraduate research process 2.4.1.1 Learning objectives and student evaluation The learning objectives for this particular project appear in Table 2.4. Table 2.4: Learning objectives. Upon successful completion of this independent research project, the student researcher will demonstrate . . . – –

The ability to integrate skills and knowledge from core chemistry courses and apply them in independent research A basic understanding of the scientific literature in the chosen area of research

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Table 2.4 (continued ) Upon successful completion of this independent research project, the student researcher will demonstrate . . . – – –

The ability to design a hypothesis and plan and execute appropriate experimental procedures The ability to interpret the results and rationalize them in the context of the hypothesis The ability to share the results and their implications professionally via written or oral scientific communication

To demonstrate competence in these areas, the students completed several tasks. Table 2.5 outlines each task, as well as its weight in the overall evaluation. Table 2.5: Research project evaluation methods. Component

Description

Weight

Research proposal

In this proposal, the student researcher will summarize the relevant scientific literature, identify a new research question, and describe an appropriate experimental protocol.

.%

Research performance evaluation

The student researcher will participate actively in researchbased learning. Throughout the term, the student should spend at least  h per week in the laboratory. The faculty mentor will base this portion of the student’s grade on direct observation of laboratory work and the student’s ability to integrate the skills learned into the final project.

%

Research progress oral presentation

Throughout the term, the student researcher will give several  min oral presentations on the project. These presentations will outline the project’s research objectives and the progress made to date. Presentations will generally occur on a biweekly basis. The faculty mentor will base this portion of the student’s grade on overall performance throughout the term.

%

Research report

The student will submit a formal written report by the due date. The research report should contain an abstract, introduction, experimental section, results and discussion, conclusion, and references.

%

Oral conference presentation

The student will present the project at the Ambrose Research Conference.

%

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2.4.1.2 Task 1: choosing a research topic This describes an independent research project of one student. As this project involved a biology student with a minor in chemistry and an interest in medicine, the topic was interdisciplinary. However, the project needed to be narrow enough to suit the given time frame, and it needed to fit roughly within the area of the faculty mentor’s expertise – in this case, green chemistry. It also needed to match the physical and financial resources of the department. The project focused on synthesizing a wound-care product, using green chemistry, and testing and characterizing that product’s antimicrobial effect. While the faculty mentor made the final choice of topic, the topic was within the student researcher’s interest area, as noted above.

2.4.1.3 Task 2: literature search and summary The undergraduate research project began with a review of the literature. The student performed a literature search on “wound-dressing and antimicrobial biopolymers” and found 388 papers. The search string was modified to “wound-dressing and antimicrobial biopolymers and review through discussion between student and supervisor.” With this modified search string, the student found 16 papers. A summary of the most applicable papers revealed the following findings [112–117]: (a) Many studies recommend the biopolymer chitosan (CS) as a wound-dressing material, as CS is biocompatible, biodegradable, antibacterial, antifungal, hemostatic, and muco-adhesive. (b) CS can be easily processed into multiple forms, including hydrogels, membranes, foams, and beads. (c) Bioactive agents such as essential oils, when combined with CS, can accelerate the healing process. On this basis, the student researcher and mentor chose to create a blend of CS and essential oils to be tested for possible antimicrobial wound-dressing material. After this initial investigation, the student researched to understand the CS and essential oils’ biochemical properties. CS is an amino polysaccharide produced from chitin’s deacetylation obtained from crustaceans and insects [118]. Specifically, CS is a linear polysaccharide consisting of β-(1-4)-D-glucosamine and N-acetyl-Dglucosamine groups. CS is well studied for its antimicrobial and antifungal activities and has been widely used in the production of wound dressings, water filters, and dentistry materials because of its biocompatibility and nontoxicity [119–127] (Figure 2.16). The student completed a further literature search to learn about essential oils. Essential oils, which are generally derived from plants, are volatile mixtures of compounds known as secondary metabolites. These secondary metabolites possess

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O O

Extraction Crustaceans

HO O

OH O

HO O

NH

NH

O

Deacetylation

O

O HO

OH

OH

NH

HO O

NH

n

O OH

n Chitin

Chitosan

Figure 2.16: Formation of chitosan. Chitin is extracted from the shell of crustaceans; this chitin is deacetylated into chitosan.

many useful biological properties: they can be antimicrobial, antioxidant, and antiinflammatory. In previous studies on CS in wound-care, researchers have incorporated several essential oils – thyme, cinnamon, tea tree, and rosemary [128, 129]. To understand these oils’ properties, the student further researched the structures of the major constituents in these oils. Figure 2.17 shows the major constituents’ structures in thyme, cinnamon, tea tree, and rosemary essential oils.

O H OH

Thymol (Thyme)

OH

Cinnamaldehyde (Cinnamon)

Terpinen-4-ol (Trea tree oil)

alpha-Pinene (Rosemary)

Figure 2.17: Structure of the principal constituent of thyme, cinnamon, tea tree oil, and rosemary.

Additional literature searches suggested that some chemical modifications of CS may be more effective, and these modified forms of CS could be combined with essential oils to form a more bioactive wound-dressing material [130–133]. Both the –NH2 and –OH groups in CS can be chemically modified to form derivatives, and, in previous studies, some of these derivatives exhibited higher antimicrobial activity than a simple blend. Specifically, researchers have found that CS -SBs have increased antimicrobial activities [134]. These CS-SBs can include chitosan-para-substituted benzaldehydes, chitosan-crotanaldehyde, chitosan-4-chlorobenzaldehyde, chitosan-indole -3-carboxaldehyde, and chitosan-4-dimethylaminobenzaldehyde [135–137].

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2.4.1.4 Task 3: testing the antimicrobial activities of essential oils Next, to determine which essential oils to use, the student researcher tested the various oils for antimicrobial activity using the disk-diffusion agar method (Table 2.6). The disk-diffusion agar method utilizes several agar plates that contain bacterial cultures, which can measure the antibacterial effects of chosen compounds. As this was not a systematic study of all companies, the essential oil manufacturer was chosen locally. For cinnamon, however, the student researcher and mentor chose to test multiple forms: cinnamon leaf oil (True Essence®) and cinnamaldehyde (Sigma-Aldrich®). The initial results showed that cinnamaldehyde had the highest antimicrobial effect. Cinnamaldehyde was much more effective than the cinnamon leaf, leading the researchers to investigate other cinnamon extract forms. A literature search revealed that cinnamon oil varies significantly in chemical composition depending on the part of the tree used in production; the bark contains the highest percentage of cinnamaldehyde (60–90%) [50]. Thus, the student hydrodistilled cinnamon oil in the lab using cinnamon bark. Cinnamon oil obtained had higher antimicrobial activity than cinnamaldehyde due to synergistic activity: some unknown compound in the cinnamon oil was working with the cinnamaldehyde to enhance its antimicrobial activity. The MIC of cinnamaldehyde and cinnamon oil against E. coli and S. aureus was 0.3 mg/mL. After cinnamon, thyme was the second most effective essential oil. The student expected to see antimicrobial activity with both rosemary and tea tree oil, as found in previous research [138]. However, the student did not observe any activity with rosemary or tea tree oil in this case. Table 2.6: Antimicrobial activity of common essential oils. Samples

S. aureus (mm)

E. coli (mm)

MIC (mg/mL)

Rosemary (True Essence)





Cinnamon leaf oil (True essence)





Clove bud (True Essence)





Tea tree oil (True Essence)





Thyme (True Essence)





Cinnamaldehyde (Sigma-Aldrich)

.

.

.

Cinnamon oil (hydrodistilled in the oil from cinnamon stick)

.

.

.

Concentration =  mg/mL DMSO

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2.4.1.5 Task 4: refining the research topic After the literature search and written summary, the student researcher and faculty mentor discussed the findings and refined the initial research problem. The revised project focused on developing and testing two bioactive wound-dressing materials synthesized from CS-SBs with essential oils containing an aldehyde functional group. The researchers chose cinnamaldehyde because of its performance in the laboratory test. The student and supervisor also chose citronellal because it is a naturally occurring aldehyde with known antifungal properties [139] (Figure 2.18). Thus, the project now focused on the synthesis and testing of CS-SBs with cinnamaldehyde (CS-CA-SB) and citronellal (CS-CL-SB) to produce a wound-dressing material (Figure 2.19). An SB is the product of an aldehyde or ketone with a primary amine, resulting in an imine. Using an SB in a wound-dressing material was decided upon because when compared to unmodified CS, SBs have been shown to have higher biological activity, particularly antimicrobial, antifungal, antimalarial, antiproliferative, and antibacterial activities [134]. SB products also have better processibility and applicability to other experiments [134]. O

O

H

H

Cinnamaldehyde

Citronellal

Figure 2.18: Structure of cinnamaldehyde and citronellal.

2.4.1.6 Task 5: Synthesis, characterization, and antimicrobial assay of CS-CA-SB and CS-CL-SB The synthesis of both SB products followed the procedure outlined by Hassan et al. [134] with slight modifications. CS (1 g) was dissolved in 50 mL of acetic acid (2%) at room temperature and stirred for 3 h. Next, cinnamaldehyde (Sigma-Aldrich®; 99%) or citronellal oil (Alfa Aesar; 96%, 2.12 mM each) was dissolved in 10 mL of ethanol and added dropwise into the CS solution; the solution was held at 50 °C and stirred overnight. The reaction mixture was turned into a yellow gel and was then filtered, and the unreacted aldehydes were removed by washing several times with ethanol. Sodium hydroxide (5%) was added dropwise to neutralize the solution. The gel was washed again with distilled water and dried overnight at 60 °C in a vacuum oven.

31

2 Applications of green chemistry in undergraduate research

The same procedure was conducted using the hydrodistilled cinnamon oil from above; however, the antimicrobial activity was the same as the cinnamaldehyde. Therefore, cinnamaldehyde was selected as the focus for the rest of the research.

O HO

OH O

+

NH2

OH

O

O

O

O

HO

H

N

n

HO

Cinnamaldehyde

Schiff's base I

O

OH O

O

n H

Chitosan

O

O

+

H

O HO

NH2

OH O

O

N

n H

n

Chitosan

Citronellal

Schiff's base II

Figure 2.19: Transformation of CS-CA and CS-CL into CS-CA-SB and CS-CL-SB, respectively.

To measure CS-CA-SB and CS-CL-SB’s antibacterial activity, the student researcher conducted agar well diffusion, using E. coli and S. aureus as indicator strains. When OD600 of the culture reached 0.6 (logarithmic phase, about 108 cells), 1 mL was taken into 100 mL of LB agar (1.5%, w/v) at 50 °C. The culture was then poured into a 10 cm round, sterile plate, and dried. Using a hole maker, the student researcher made a well 5 mm in diameter in the middle of the culture. About 50 mg of CS-CASB or CS-CL-SB material was added to the well. In each case, the plate was incubated for 12 h at 37 °C. Antimicrobial activity was measured based on the diameter of the inhibition zone.

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2.4.2 Results 2.4.2.1 Characterization of CS-CA-SB and CS-CL-SB The laboratory did not have FTIR spectroscopy or a scanning electron microscope (SEM) for characterization, so the samples were sent to another institution for analysis. SEM analysis showed the CS and CS-SB’ structure, allowing the researchers to confirm successful synthesis. Figure 2.20 shows the SEM of SBs. In comparison to unmodified CS, both SBs appear irregular due to the CS structure’s interruption. This change in surface morphology of the microstructure of CS demonstrates that product formation has occurred.

Figure 2.20: SEM of chitosan, CS-CA-SB, and CS-CL-SB products.

Figure 2.21 shows the FTIR-ATR spectrum of both SBs, CS-CA-SB, and CS-CL-SB, along with the FTIR-ATR spectrum for unmodified CS. The band around 3,440 cm−1 corresponds to the –OH and –NH stretching and the band around 2800–2950 cm−1 belongs to the –CH and –CH2 groups. The peak around 1,650 corresponds to the C = N stretching. The results of three runs of the antimicrobial assay (shown in Figure 2.22) confirm both SB products’ antimicrobial activity. CS-CA-SB and CS-CL-SB were both highly active against bacteria, including gram-negative and gram-positive bacteria. E. coli and S. aureus were chosen because they are considered the representative pathogens for gram-negative and gram-positive bacteria, respectively. A control

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Figure 2.21: FTIR of chitosan, CS-CA, and CS-CL Schiff base products.

trial was also performed (not pictured), which displayed no activity for unmodified CS powder. Unmodified CS powder was chosen as a control in place of CS powder dissolved in acetic acid. It is difficult to state whether the antimicrobial effects come from the CS or from the acetic acid needed to dissolve the CS.

Figure 2.22: Microbial assay of CS-CA and CS-CL Schiff base products.

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An antifungal assay was not performed because of time constraints; however, research points to the antifungal properties of these materials [140]. Furthermore, the next step would be to embed these products into a wound-dressing material, but due to time constraints, this was not completed.

2.4.3 Discussion: benefits and costs 2.4.3.1 Scientific benefits: the product The results displayed in Figures 2.5–2.7 confirm that the procedure successfully synthesized the SBs and that both CS-CA-SB and CS-CL-SB had high antimicrobial activities. The antimicrobial assay emphasizes that cinnamaldehyde’s antimicrobial activity, citronellal, and CS remains after modification to form an SB. Because both CA-CS-SB and CL-CS-SB displayed antimicrobial activities, these bioinspired SBs are great candidates for safe, effective, and environmentally friendly wound-dressing materials.

2.4.3.2 Pedagogical benefits: green chemistry Moreover, in addition to producing valuable wound-care materials, this project had a significant pedagogical value. In particular, the student had an opportunity to become more familiar with – and intentionally design a procedure using – the principles of green chemistry. The mentor and student both strove to reduce the research’s environmental footprint and avoid any toxicity. These priorities affected all decisions about the procedure: choice of reactant, amount of reactant, disposal of products, and so on. As a result of this careful design, the project followed all 12 principles of green chemistry, as described further [3]: – Principles 1 and 2. The procedure generated no waste, as the aldehydes, cinnamaldehyde, and citronellal were integrated into the final product. For the same reason, the experiment illustrated the atom economy: reactants were incorporated into the final product. – Principles 3 and 4. The reaction produced a functional, effective product but did not require or produce harmful substances to humans or the environment. Instead, the procedure used bioinspired, environmentally friendly materials with very minimal toxicity and excellent antimicrobial activity. – Principle 5. The process did not rely on toxic or volatile organic solvents, as reactions were carried out in the water. – Principle 6. The process was not energy-intensive: the reactions occurred at low temperatures (highest temperature: 60 °C), ambient pressure, and processes requiring energy input relatively short (maximum time: 12 h).

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– – – –

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Principle 7. All the starting materials for the reactions came from renewable feedstocks. Principles 8 and 9. The reactions required no derivatives or protecting groups and did not rely on stoichiometric reagents. Principle 10. The products biodegrade and thus pose no threat to the environment. Principles 11 and 12. None of the reactions involved a risk of chemical accidents or pollution. All processes were monitored carefully, and the final tests confirmed that the expected reactions had, indeed, occurred.

This research project, then, provided a valuable opportunity for the student to develop a responsible approach to chemistry, one that uses environmentally safe and sustainable processes.

2.4.3.3 Pedagogical benefits: scientific inquiry and interdisciplinary research Like many undergraduate research projects, this project also allowed the student to experience the process of scientific inquiry and independent thought. While the faculty mentor assisted and advised along the way, especially with experiment design, the student researcher reviewed the literature, conducted the procedures, and analyzed the results fairly independently, gaining experience in the process of scientific research. Moreover, because this experiment drew on green chemistry, medicinal chemistry, materials chemistry, polymer chemistry, microbiology, spectroscopy, and human physiology, it invited creative interdisciplinary thinking. By this point in their degrees, most students have taken at least introductory chemistry, microbiology, and physiology courses, so an independent research project invites them to implement previous knowledge and practice laboratory skills in a relevant research context. Arguably, the most valuable research is not restricted to one discipline, and therefore undergraduate researchers can benefit from experience in crossing borders between disciplines and exposing themselves to information and techniques outside their comfort zone.

2.4.3.4 Faculty benefits: integration of teaching and research Finally, the project had added benefit for the faculty mentor because she/he could pursue her/his scholarly research interests while also fulfilling her/his teaching duties. At institutions with heavy teaching loads, faculty members often have little time for research and publication. By participating in undergraduate research, faculty members can maintain a healthy balance between research and teaching.

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2.4.3.5 Costs: time and resources In the research project described above, these benefits came at a relatively low cost, especially in terms of resources. As noted above, Ambrose has only a teaching laboratory and has limited chemistry equipment, yet this procedure was feasible, given the tools available. Certainly, the FTIR and SEM analysis had to be conducted offsite, but the student still had ample opportunity for hands-on lab work and data interpretation. Besides, the financial cost was quite low. The project was still timeconsuming for the faculty mentor, which may make undergraduate research less feasible in some contexts. However, because the procedure followed green chemistry principles, it was doable even in a small institution with a limited budget and equipment.

2.5 Summary The laboratory experiments allowed students to learn about green chemistry principles in a practical context while practicing standard reaction and characterization techniques. This detailed account describes how a series of laboratories were designed to provide tangible ways to introduce green chemistry to undergraduate students and incorporate several other objectives while meeting the foundational objectives of existing organic chemistry experiments. We hope this low-cost and waste-minimizing project design will be a useful tool to other departments that aim to incorporate green chemistry into their courses and will inspire the development of other useful green laboratories to educate and equip the upcoming generation of young chemists with important concepts and practical skills to apply in our increasingly sustainable world. The dyeing of cellulose cotton fiber with Procion reactive dyes from real-life examples employed 9 of the 12 green chemistry principles in an SNAr reaction while providing students with a fun and engaging real-life practical application of dyeing chemistry. Through carrying out the experiment as well as the subsequent activities and discussions, students gained exposure to systems thinking and life cycle thinking, recognized the interconnectedness of chemicals and their surroundings, and practically engaged in environmental stewardship. The research project provides an example of how undergraduate research can thrive even in contexts where resources are scarce. It provides further support to previous studies on the benefits of undergraduate research and offers a model for achieving those goals practically while minimizing costs. In particular, this project shows the value of green chemistry for those offering undergraduate research opportunities.

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References Tundo, P.; Grigual, E. Green Chemistry for Sustainable Development. Chem. Int.. 2018, 40(1), 18–24. [2] Constable, D. J. C. The Practice of Chemistry Still Needs to Change. Curr. Opin Green Sustain. Chem.. 2017, 7, 60–62. [3] Anastas, P. T.; Warner, J. S. Green Chemistry: Theory and Practice; Oxford Univ. Press: Oxford, England, 1998. [4] What is Green Chemistry? https://www.acs.org/content/acs/en/greenchemistry/what-isgreen-chemistry.html (accessed May 2019). [5] https://www.epa.gov/greenchemistry/basics-green-chemistry#definition [6] Anastas, P. T.; Zimmerman, J. B. The United Nations Sustainability Goals: How Can Sustainable Chemistry Contribute? Curr. Opin. Green Sustain. Chem.. 2018, 13, 150–153. [7] Anastas, P. T.; McKeag, T. A. Shaping the Future of Additive Manufacturing: Twelve Themes from Bio-Inspired Design and Green Chemistry. Handb. Green Chem.. 2018, 10, 241–262. [8] Anastas, P. T.; Zimmerman, J. B.; McDonough, W.; Braungart, M. Applying the Principles of Green Engineering to Cradle-to-Cradle Design. Environ. Sci. Technol.. 2003, 37(25), 434A−441A. [9] Lavoie, E. T.; Heine, L. G.; Holder, H.; Rossi, M. S.; Lee, R. E.; Connor, E. A.; Vrabel, M. A.; DiFiore, D. M.; Davies, C. L. Chemical Alternatives Assessment: Enabling Substitution to Safer Chemicals. Environ. Sci. Technol.. 2010, 44(24), 9244–9249. [10] Dintzner, M. R.; Wucka, P. R.; Lyons, T. W. Microwave-Assisted Synthesis of a Natural Insecticide on Basic Montmorillonite K 10 Clay. Green Chemistry in the Undergraduate Organic Laboratory. J. Chem. Educ.. 2006, 83(2), 270. [11] Dintzner, M. R.; Kinzie, C. R.; Pulkrabek, K.; Arena, A. F. The Cyclohexanol Cycle and Synthesis of Nylon 6, 6: Green Chemistry in the Undergraduate Organic Laboratory. J. Chem. Educ.. 2012, 89(2), 262–264. [12] Doxsee, K. M.; Hutchison, J. E. Green Organic Chemistry: Strategies, Tools, and Laboratory Experiments; Thomson-Brooks/Cole: Southbank, 2004. [13] Dicks, A. P. Green Organic Chemistry in Lecture and Laboratory; Taylor & Francis: Boca Raton, FL, 2012. [14] Levy, I. J.; Haack, J. A.; Hutchison, J. E.; Kirchoff, M. M. Going Green: Lecture Assignments and Lab Experiences for the College Curriculum. J. Chem. Educ.. 2005, 82(7), 974–976. [15] Roesky, H. W.; Kennepohl, D. K.; Lehn, J. M.; Luque, R.; Clark, J. H.; Macquarrie, D. J.; Carril, M.; SanMartin, R.; Dominques, E.; Gossage, R. A. Experiments in Green and Sustainable Chemistry; Wiley-VCH: Weinheim, Germany, 2009. [16] http://advancinggreenchemistry.org/benchmarking/education/green-chemistry-is-emerging -in-academic-institutions-all-over-the-world/ [17] Kennedy, S. A. Design of a Dynamic Undergraduate Green Chemistry Course. J. Chem. Educ.. 2016, 93(4), 645–649. [18] Armstrong, L. B.; Rivas, M. C.; Zhou, Z.; Irie, L. M.; Kerstiens, G. A.; Robak, M. T.; Douskey, M. C.; Baranger, A. M. Developing a Green Chemistry Focused General Chemistry Laboratory Curriculum: What Do Students Understand and Value about Green Chemistry?. J. Chem. Educ.. 2019, 96(11), 2410–2419. [19] Waked, A. E.; Demman, K. Z.; Hems, R. F.; Reyes, L. M.; Mallow, I.; Daley, E.; Hoch, L. B.; Mastronardi, M. L.; Franier De La, B. J.; Borduas-Dedekind, N.; Dicks, A. P. The Green Chemistry Initiative’s Contributions to Education at the University of Toronto and Beyond. Green Chem. Lett. Rev.. 2019, 12(2), 187–195.

[1]

38

Liza Abraham

[20] Blatti, J. L. Colorful and Creative Chemistry: Making Simple Sustainable Paints with Natural Pigments and Binders. J. Chem. Educ.. 2016, 94(2), 211–215. [21] Dicks, A. P. Microwave Reactivity and Energy Efficiency in the Undergraduate Organic Laboratory; Elsevier, 2019, 85–115. [22] Lam, C. H.; Escande, V.; Mellor, K. E.; Zimmerman, J. B.; Anastas, P. T. Teaching Atom Economy and E-Factor Concepts through a Green Laboratory Experiment: Aerobic Oxidative Cleavage of meso-Hydrobenzoin to Benzaldehyde Using a Heterogeneous Catalyst. J. Chem. Educ.. 2019, 96(4), 761–765. [23] Purcell, S. C.; Pande, P.; Lin, Y.; Rivera, E. J.; Paw, U., . P.; Smallwood, L. M.; Kerstiens, G. A.; Armstrong, L. B.; Robak, M. T.; Baranger, A. M.; Douskey, M. C. Extraction and Antibacterial Properties of Thyme Leaf Extracts: Authentic Practice of Green Chemistry. J. Chem. Educ.. 2016, 93(8), 1422–1427. [24] Johnston, A.; Scaggs, J.; Mallory, C.; Haskett, A.; Warner, D.; Brown, E.; Hammon, K.; Mccormick, M. M.; Mcdougal, O. M.; Green, A. Approach to Separate Spinach Pigments by Column Chromatography. J. Chem. Educ.. 2013, 90(6), 796–798. [25] Wu, N.; Kubo, T.; Sekoni, K. N.; Hall, A. O.; Phadke, S.; Zurcher, D. M.; Wallace, R. L.; Kothari, D. B.; Mcneil, A. J. Student-Designed Green Chemistry Experiment for a Large-Enrollment, Introductory Organic Laboratory Course. J. Chem. Educ.. 2019, 96(11), 2420–2425. [26] McKenzie, L. C.; Huffman, L. M.; Hutchison, J. E.; Rogers, C. E.; Goodwin, T. E.; Spessard, G. O. Greener Solutions for the Organic Chemistry Teaching Lab: Exploring the Advantages of Alternative Reaction Media. J. Chem. Educ.. 2009, 86(4), 488. [27] Ward, A. M.; Wyllie, G. R. A. Bioplastics in the General Chemistry Laboratory: Building Semester-Long Research Experience. J. Chem. Educ.. 2019, 96(4), 668–676. [28] Abraham, L.; VanderZwaag, J.; Chao, D. H. (Manuscript Accepted) Motivating and Supporting Undergraduate Research through Green Chemistry: Experiences at a Small Liberal Arts University. J. Chem. Educ. [29] Abraham, L.; Stachow, L.; Chao Cinnamon, D. H. Oil: An Alternate and Inexpensive Resource for Green Chemistry Experiments in Organic Chemistry Laboratory. J. Chem. Educ.. 2020, 97 (10), 3797–3805. [30] Abraham, L. A Green Nucleophilic Aromatic Substitution Reaction. J. Chem. Educ.. 2020, 97 (10), 3810–3815. [31] Martin, E.; Kellen-Yuen, C. Microwave-Assisted Organic Synthesis in the Organic Teaching Lab: A Simple, Greener Wittig Reaction. J. Chem. Educ.. 2007, 84(12), 2004. [32] Morra, B.; Dicks, A. P. Recent Progress in Green Undergraduate Organic Laboratory Design. J. Chem. Educ.. 2016, 7–32. [33] Sutheimer, S.; Caster, J. M.; Smith, S. H. Green Soap: An Extraction and Saponification of Avocado Oil. J. Chem. Educ.. 2015, 92(10), 1763–1765. [34] Fahey, J. T.; Maelia, L. E. Greening Undergraduate Organic Laboratory Experiments; American Chemical Society: Washington, DC, 2016, 153–168. [35] Wu, N.; Kubo, T.; Sekoni, K. N.; Hall, A. O.; Phadke, S.; Zurcher, D. M.; Wallace, R. L.; Kothari, D. B.; McNeil, A. J. Student-Designed Green Chemistry Experiment for a Large-Enrollment, Introductory Organic Laboratory Course. J. Chem. Educ.. 2019, 96(11), 2420–2425. [36] Zhou, H.; Zhan, W.; Wang, L.; Guo, L.; Liu, Y. Making Sustainable Biofuels and Sunscreen from Corncobs to Introduce Students to Integrated Biorefinery Concepts and Techniques. J. Chem. Educ.. 2018, 95(8), 1376–1380. [37] McKenzie, L. C.; Huffman, L. M.; Hutchison, J. E. The Evolution of a Green Chemistry Laboratory Experiment: Greener Brominations of Stilbene. J. Chem. Educ.. 2005, 82(2), 306. [38] Leung, S. H.; Angel, S. A. Solvent-Free Wittig Reaction: A Green Organic Chemistry Laboratory Experiment. J. Chem. Educ. 2004, 81(10), 1492.

2 Applications of green chemistry in undergraduate research

39

[39] Biswas, R.; Mukherjee, A. Introducing the Concept of Green Synthesis in the Undergraduate Laboratory: Two-Step Synthesis of 4-Bromoacetanilide from Aniline. J. Chem. Educ. 2017, 94 (9), 1391–1394. [40] Hurst, G. A.; Slootweg, J. C.; Balu, A. M.; Climent-Bellido, M. S.; Gomera, A.; Gomez, P.; Luque, R.; Mammino, L.; Spanevello, R. A.; Saito, K.; Ibanez, J. G. International Perspectives on Green and Sustainable Chemistry Education via Systems Thinking. J. Chem. Educ. 2019, 96(12), 2794–2804. [41] Dicks, A. P.; D’eon, J. C.; Morra, B.; Chisu, C. K.; Quinlan, K. B.; Cannon, A. S. A Systems Thinking Department: Fostering A Culture of Green Chemistry Practice among Students. J. Chem. Educ. 2019, 96(12), 2836–2844. [42] Matlin, S. A.; Mehta, G.; Hopf, H.; Krief, A. One-world Chemistry and Systems Thinking. Nat. Chem. 2016, 8, 393–398. [43] Aubrecht, K. B.; Bourgeois, M.; Brush, E. J.; MacKellar, J.; Wissinger, J. E. Integrating Green Chemistry in the Curriculum: Building Student Skills in System Thinking, Safety and Sustainability. J. Chem. Educ. 2019, 96(12), 2872–2880. [44] Mahaffy, P. G.; Krief, A.; Hopf, H.; Mehta, G.; Matlin, S. A. Reorienting Chemistry Education through Systems Thinking. Nat. Rev. Chem. 2018, 2, 1–3. [45] Orgill, M. K.; York, S.; MacKellar, J. Introduction to Systems Thinking for the Chemistry Education Community. J. Chem. Educ. 2019, 96(12), 2720–2729. [46] York, S.; Lavi, R.; Dori, Y. J.; Orgill, M. Applications of Systems Thinking in Stem Education. J. Chem. Edu. 2019, 96(12), 2742–2751. [47] Ginzburg, A. L.; Check, C. E.; Hovekamp, D. P.; Sillin, A. N.; Brett, J.; Eshleman, H.; Hutchison, J. E. Experiential Learning to Promote Systems Thinking in Chemistry: Evaluating and Designing Sustainable Products in a Polymer Immersion Lab. J. Chem. Educ. 2019, 96(12), 2863–2871. [48] United States Government Accountability Office. Chemical Innovation: Technologies to Make Process and Products More Sustainable; 2018; 159. https://www.gao.gov/products/gao-18307 (accessed Jan4, 2020) [49] Schwarzman, M. R.; Buckley, H. L. Not Just an Academic Exercise: System Thinking Applied to Designing Safer Alternatives. J. Chem. Educ. 2019, 96(12), 2984–2425. [50] Wong, Y.; Ahmad-Mudzaqqir, M.; Wan-Nurdiyana, W. Extraction of Essential Oil from Cinnamon (Cinnamomum zeylanicum). Oriental J. Chem. 2014, 30(1), 37–47. [51] Nabavi, S. F.; Lorenzo, A. D.; Izardi, M.; Sobarzo-Sánchez, E.; Daglia, M.; Nabavi, S. M. Antibacterial Effects of Cinnamon: From Farm to Food, Cosmetic and Pharmaceutical Industries. Nutrients. 2015, 7(9), 7729–7748. [52] Utchariyakiat, I.; Surassmo, S.; Jaturanpinyo, M.; Khuntayaporn, P.; Chomnawang, M. T. Efficacy of Cinnamon Bark Oil and Cinnamaldehyde on Anti-multidrug Resistant Pseudomonas Aeruginosa and the Synergistic Effects in Combination with Other Antimicrobial Agents. BMC Complement Altern. Med. 2016, 16(1), 158–164. [53] Letizia, C. S.; Cocchiara, J.; Lalko, J.; Lapczynski, A.; Api, A. M. Fragrance Material Review on Cinnamyl Alcohol. Food Chem. Toxicol. 2005, 43(6), 837–866. [54] Celik, H.; Maman, M.; Babagil, A. Cinnamaldehyde and Pmethoxycinnamaldehyde Derived Schiff Bases Antibacterial Activities. J. Sci. & Eng. Res. 2018, 9(10), 640–651. [55] Nair, M. S.; Arish, D.; Joseyphus, R. S. Synthesis, Characterization, Antifungal, Antibacterial and DNA Cleavage Studies of Some Heterocyclic Schiff Base Metal Complexes. J. Saudi Chem. Soc. 2012, 16(1), 83–88. [56] Desai, S. B.; Desai, P. B.; Desai, K. R. Synthesis of Some Schiff Bases, Thiazolidones, and Azetidinones Derived from 2.6-diaminobenzo[1,2-d:4,5-d’] Bisthiazole and Their Anticancer Activities. Heterocycl. Commun. 2001, 7(1), 83–90.

40

[57]

[58] [59]

[60]

[61]

[62] [63]

[64] [65] [66] [67]

[68] [69]

[70] [71]

[72] [73] [74]

[75]

Liza Abraham

Castelino, P. A.; Dasappa, J. P.; Bhat, K. G.; Joshi, S. A.; Jalapure, S. Some Novel Schiff Bases of [1,2,4]triazole Bearing Haloarene Moiety – synthesis and Evaluation of Antituberculosis Properties and Neutrophil Function Test. Med. Chem. Res. 2015, 25(1), 83–93. Zhu, S.; Xu, S.; Jing, W.; Zhao, Z.; Jiang, J. Synthesis and Herbicidal Activities of p-Menth-3en1-amine and Its Schiff Base Derivatives. J. Agric. Food. Chem. 2016, 64(51), 9702–9707. Pandeya, S. N.; Sriram, D.; Nath, G.; De Clercq, E. Synthesis, Antibacterial, Antifungal and anti-HIV Activities of Schiff and Mannich Bases Derived from Isatin Derivatives and N-[4-(4′chlorophenyl)thiazol-2-yl] Thiosemicarbazide. Eur. J. Pharm. Sci. 1999, 9(25), 25–31. Jarrahpour, A.; Shirvani, P.; Sharghi, H.; Aberi, M.; Sinou, V.; Latour, C.; Brunel, J. M. Synthesis of Novel Mono- and bis-Schiff Bases of Morpholine Derivatives and the Investigation of Their Antimalarial and Antiproliferative Activities. Med. Chem. Res. 2015, 24 (1), 25–31. Da Silva, C. M.; Silva, M. M.; Reis, F. S.; Ruiz, A. L. T.; De Carvalho, J. E.; Santos, J. C. C.; Figueired, I. M.; Alves, R. B.; Modolo, L. V.; Fátima, A. D. Studies on Free Radical Scavenging, Cancer Cell Antiproliferation, and Calf Thymus DNA Interaction of Schiff Bases. J. Photochem. Photobiol. B. 2017, 172, 129–138. Zhang, B.; Liu, Y.; Wang, Z.; Lia, Y.; Wang, Q. Antiviral Activity and Mechanism of Gossypols: Effects of the O2˙− Production Rate and the Chirality. RCS Adv. 2017, 7(17), 10266–10277. Murtaza, S.; Akhtar, M. S.; Kanwal, F.; Abbas, A.; Ashiq, S.; Shamim, S. Synthesis and Biological Evaluation of Schiff Bases of 4-aminophenazone as an Anti-inflammatory, Analgesic and Antipyretic Agent. J. Saudi Chem. Soc. 2017, 21, 359–372. Alam, M. S.; Choi, J. H.; Lee, D. U. Synthesis of Novel Schiff Base Analogues of 4-amino -1,5dimethyl-2-phenylpyrazol-3-one and their Evaluation for Antioxidant. Varma, R. S.; Dahiya, R.; Kumar, S. Clay Catalyzed Synthesis of Imines and Enamines under Solvent-free Conditions Using Microwave Irradiation. Tetrahed. Lett. 1997, 38, 2039–2042. Schmeyers, J.; Toda, F.; Boy, J.; Kaupp, G. Quantitative Solid–solid Synthesis of Azomethines. J. Chem. Soc. Perkin Trans. 2. 1998, (4), 989–994. Rao, V. K.; Reddy, S. S.; Krishna, B. S.; Naidu, K. R. M.; Raju, C. N.; Ghosh, S. K. Synthesis of Schiffs Bases in Aqueous Medium: A Green Alternative Approach with Effective Mass Yield and High Reaction Rates. Green Chem. Lett. Rev. 2010, 3(3), 217–223. Rai, R.; Shanmugga, S. C.; Srinivas, C. R. Update on Photoprotection. Indian J. Dermatol. 2012, 57(5), 335–342. Du, H.; Yang, J.; Lu, X.; Lu, Z.; Bie, X.; Zhao, H.; Zhang, C.; Lu, F. Purification, Characterization, and Mode of Action of Plantaricin GZ1-27, a Novel Bacteriocin Against Bacillus cereus. J. Agric. Food Chem. 2018, 66(18), 4716–4724. Alwaseem, H.; Donahue, C. J.; Marincean, S. Catalytic Transfer Hydrogenation of Castor Oil. J. Chem. Educ. 2014, 91(4), 575–578. Taber, D. F.; Frankowski, K. J. Grubbs’s Cross Metathesis of Eugenol with Cis-2-Butene-1,4Diol to Make a Natural Product. An Organometallic Experiment for the Undergraduate Lab. J. Chem. Educ. 2006, 83(2), 283–284. Besse, P.; Bolte, J.; Veschambre, H. Baker’s Yeast Reduction of Alpha-Diketones: A Four-Hour Experiment for Undergraduate Students. J. Chem. Educ. 1995, 72(3), 277–278. Silverman, J. R. Biobased Organic Chemistry Laboratories as Sustainable Experiment Alternatives. J. Chem. Educ. 2016, 93, 1679–1681. Montana-Hoyos, C.; Fiorentino, C. Bio-utilization, Bioinspiration, and Bio-affiliation in Design for Sustainability: Biotechnology, Biomimicry, and Biophilic Design. Int. J. Des. Objects. 2016, 10(3), 1–18. Anastas, P. T.; McKeag, T. A. Shaping the Future of Additive Manufacturing: Twelve Themes from Bio-Inspired Design and Green Chemistry. Handb Green Chem. 2018, 10, 241–262.

2 Applications of green chemistry in undergraduate research

41

[76] Hwang, H. L.; Rohidas, S.; Jadhav, J.; Silverman, R.; John, G. Sweet, and Sustainable: Teaching the Biorefinery Concept through Biobased Gelator Synthesis. J. Chem. Educ. 2014, 91(10), 1563–1568. [77] Mackenzie, L. S.; Tyrrell, H.; Thomas, R.; Matharu, A. S.; Clark, J. H.; Hurst, G. A. Valorization of Waste Orange Peel to Produce Shear-Thinning Gels. J. Chem. Educ. 2019, 96(12), 3025–3029. [78] Miles, W. H.; Connell, K. B. Synthesis of Methyl Diantilis, a Commercially Important Fragrance. J. Chem. Educ. 2006, 83(2), [79] Ravía, S.; Gamenara, D.; Schapiro, V.; Bellomo, A.; Adum, J.; Seoane, G.; Gonzalez, D. Enantioselective Reduction by Crude Plant Parts: Reduction of Benzofuran-2-Yl Methyl Ketone with Carrot (Daucus carota) Bits. J. Chem. Educ. 2006, 83(7), 1049–1052. [80] Mohan, R. S.; Mejia, M. P. Environmentally Friendly Organic Chemistry Laboratory Experiments for the Undergraduate Curriculum: A Literature Survey and Assessment. J. Chem. Educ. 2020, 97(4), 943–959. [81] Brown, W. H.; Foote, C. S.; Iverson, B. L.; Anslyn, E. V.; Novak, B. M. Organic Chemistry; Brooks/Cole: New York, 2011, 924–932. [82] Landstrom, E. B.; Nichol, M.; Lipshutz, B. H.; Gainer, M. J. Discovery-Based SNAr Experiment in Water Using Micellar Catalysis. J. Chem. Educ. 2019, 96(16), 2668–2671. [83] Latimer, D.; Wiebe, M. Greening the Organic Chemistry Laboratory: A Comparison of Microwave-assisted and Classical Nucleophilic Aromatic Substitution Reactions. Green Chem. Lett. Rev. 2015, 8(2), 39–42. [84] Rizvi, W.; Khwaja, E.; Siddiqui, S.; Bhupathiraju, N. V. S. D. K.; Drain, C. M. Experimental Determination of Activation Energy of Nucleophilic Aromatic Substitution on Porphyrins. J. Chem. Educ. 2018, 95, 164–168. [85] Goodrich, S.; Patel, M.; Woydziak, Z. R. Synthesis of a Fluorescent Acridone Using a Grignard Addition, Oxidation, and Nucleophilic Aromatic Substitution Reaction Sequence. J. Chem. Educ. 2015, 92, 1221–1225. [86] Morra, B. The Chemistry Connections Challenge: Encouraging Students to Connect Course Concepts with Real-World Applications. J. Chem. Educ. 2018, 95(12), 2212–2215. [87] Bonneau, M. C. The Chemistry of Fabric Reactive Dyes. J. Chem. Educ. 1995, 72(8), 724. [88] Bopegedera, A. M. R. P. Tie-Dye! an Engaging Activity to Introduce Polymers and Polymerization to Beginning Chemistry Students. J. Chem. Educ. 2017, 94(11), 1725–1732. [89] Key, J. A.; Li, M. D.; Cairo, C. W. A Fluorogenic Aromatic Nucleophilic Substitution Reaction for Demonstrating Normal-Phase Chromatography and Isolation of Nitrobenzoxadiazole Chromophores. J. Chem. Educ. 2011, 88(1), 98–100. [90] Mottishaw, J. D.; Erck, A. R.; Kramer, J. H.; Sun, H.; Koppang, M. Electrostatic Potential Maps and Natural Bond Orbital Analysis: Visualization and Conceptualization of Reactivity in Sanger’s Reagent. J. Chem. Educ. 2015, 92(11), 1846–1852. [91] Rizvi, W.; Khwaja, E.; Siddiqui, S.; Bhupathiraju, N. V. S. D. K.; Drain, C. M. Experimental Determination of Activation Energy of Nucleophilic Aromatic Substitution on Porphyrins. J. Chem. Educ. 2017, 91(1), 164–168. [92] Santos, E. S.; Garcia, I. C. G.; Gomez, E. F. L.; Vilchis-Reyes, M. A. Synthesis of ArylSubstituted 2,4-Dinitrophenylamines: Nucleophilic Aromatic Substitution as a ProblemSolving and Collaborative-Learning Approach. J. Chem. Educ. 2010, 87(11), 1230–1232. [93] Avila, W. B.; Crow, J. L.; Utermoehlen, C. M. Nucleophilic Aromatic Substitution: A Microscale Organic Experiment. J. Chem. Educ. 1990, 67(4), 350. [94] Taber, D. F.; Brannick, S. J. One-Step Preparation of a Crystalline Product by Nucleophilic Aromatic Substitution. J. Chem. Educ. 2015, 92(7), 1261–1262.

42

Liza Abraham

[95] Wertz, J.-L.; Mercier, J. P.; Bédué, O. Cellulose Science and Technology; EFPL Press: Lausanne, 2010. [96] Clark, M. Handbook of Textile and Industrial Dyeing; Woodhead Publishing: Cambridge, UK, 2011. [97] Chakraborty, J. N. Fundamentals and Practices in Coloration of Textiles; Woodhead Publishing India: Cambridge, UK, 2010. [98] Majumdar, A.; Das, A.; Alagirusamy, R.; Kothari, V. K. Process Control in Textile Manufacturing; Woodhead Publishing: Cambridge, UK, 2013. [99] Mao, X.; Zhong, Y.; Xu, H.; Zhang, L.; Sui, X.; Mao, Z. A Novel Low Add-on Technology of Dyeing Cotton Fabric with Reactive Dyestuff. Text. Res. J. 2018, 88(12), 1345–1355. [100] Zhao, H.; Kwak, J. H.; Zhang, Z. C.; Brown, H. M.; Arey, B. W.; Holladay, J. E. Studying Cellulose Fiber Structure by SEM, XRD, NMR, and Acid Hydrolysis. Carbohydr. Polym. 2007, 68, 235–241. [101] Encyclopedia Britannica Online Academic Edition; Encyclopedia Britannica Inc.: London, 2011. [102] Tony, M. A.; Mansour, S. A. Removal of the Commercial Reactive Dye Procion Blue MX-7RX from Real Textile Wastewater Using the Synthesized Fe2O3 Nanoparticles at Different Particle Sizes as a Source of Fenton’s Reagent. Nanoscale Adv. 2019, 1, 1362–1371. [103] George, M. D.; Bragg, S.; Santos, A. G.; Denton, D. D.; Gerber, P.; Lindquist, M. M.; Rosser, J. M.; Sanchez, D. A.; Meyers, C. Shaping the Future: New Expectations for Undergraduate Education in Science, Mathematics, Engineering, and Technology; National Science Foundation, 1996, 96–139. [104] National Research Council Staff. Science Teaching Reconsidered: A Handbook; National Academies Press: Washington, DC, 1997. [105] Kuh, G. High-impact Educational Practices: What They Are, Who Has Access to Them, and Why They Matter; American Association of American Colleges & Universities: Washington, DC, 2008. [106] Healey, M.; Jenkins, A. Developing Undergraduate Research and Inquiry; The Higher Education Academy: New York, United Kingdom, 2009. [107] Boyer Commission on Educating Undergraduates in the Research University. Reinventing Undergraduate Education: A Blueprint for America’s Research Universities; State University of New York at Stony Brook for the Carnegie Foundation for the Advancement of Teaching: Stony Brook, NY, 1998. [108] Seymour, E.; Hunter, A. B.; Laursen, S. L.; DeAntoni, T. Establishing the Benefits of Research Experiences for Undergraduates in the Sciences: First Findings from a Three-year Study. Sci. Educ. 2004, 88, 493–534. [109] Council on Undergraduate Research. Strategic Pillars. https://www.cur.org/who/organiza tion/pillars/ (accessed Apr 2020). [110] Developing and Maintaining a Successful Undergraduate Research Program. In: Chapp, T. W.; Benvenuto, M. A. Eds., ACS Symposium Series 1156; American Chemical Society: Washington DC, 2013. [111] Best Practices for Supporting and Expanding Undergraduate Research in Chemistry. In: Gourley, B. L.; Jones, R. M. Eds., ACS Symposium Series 1275; American Chemical Society: Washington, DC, 2018. [112] Hosseinnejad, M.; Jafari, S. M. Evaluation of Different Factors Affecting Antimicrobial Properties of Chitosan. Int. J. Biol. Macromol. 2016, 85, 467–475. [113] Islam, S.; Bhuiyan, M. A. R.; Islam, M. N. Chitin and Chitosan: Structure, Properties and Applications in Biomedical Engineering. J. Polym. Environ. 2017, 25, 854–866.

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[114] Santos, E. P.; Nicácio, P. H. M.; Barbosa, F. C.; Nunes da Silva, H.; Andrade, A. L. S.; Lia Fook, M. V.; de Lima Silva, S. M.; Leite, I. F. Chitosan/Essential Oils Formulations for Potential Use as Wound Dressing: Physical and Antimicrobial Properties. Materials (Basel). 2019, 12(14), 2223. [115] Croisier, F.; Jérôme, C. Chitosan-Based Biomaterials for Tissue Engineering. Euro. Polym. J. 2013, 49(4), 780–792. [116] Ahmed, S.; Ikram, S. Chitosan Based Scaffolds and Their Applications in Wound Healing. Achiev. Life Sci. 2016, 10(1), 27–37. [117] Matica, A. A.; Aachmann, F. L.; Tøndervik, A.; Sletta, H.; Ostafe, V. Chitosan as a Wound Dressing Starting Material: Antimicrobial Properties and Mode of Action. Int. J. Mol. Sci. 2019, 20(23), 5889–5922. [118] Rinaudo, M. Chitin and Chitosan: Properties and Applications. Prog. Polym. Sci. 2006, 31, 603–632. [119] Pérez-Álvarez, L.; Ruiz-Rubio, L.; Vilas-Vilela, J. L. Determining the Deacetylation Degree of Chitosan: Opportunities to Learn Instrumental Techniques. J. Chem. Educ. 2018, 95(6), 1022–1028. [120] Hudson, R.; Glaisher, S.; Bishop, A.; Katz, J. L. From Lobster Shells to Plastic Objects: A Bioplastics Activity. J. Chem. Educ. 2015, 92(11), 1882–1885. [121] Hurst, G. A. Green and Smart: Hydrogels to Facilitate Independent Practical Learning. J. Chem. Educ. 2017, 94(11), 1766–1771. [122] Lawrie, G.; Keen, I.; Drew, B. Interactions between Alginate and Chitosan Biopolymers Characterized Using FTIR and XPS. Biomacromolecules. 2007, 8(8), 2533–2541. [123] Mathur, N. K.; Narang, C. K. Chitin and Chitosan, Versatile Polysaccharides from Marine Animals. J. Chem. Educ. 1990, 67(11), 938–942. [124] Prashanth, K. H.; Tharanathan, R. Chitin/Chitosan: Modifications and Their Unlimited Application Potential – An Overview. Trends Food Sci. Technol. 2007, 18(3), 117–131. [125] Rodríguez-Vázquez, M.; Vega-Ruiz, B.; Ramos-Zúñiga, R.; Saldaña-Koppel, D. A.; QuiñonesOlvera, L. F. Chitosan and Its Potential Use as a Scaffold for Tissue Engineering in Regenerative Medicine. BioMed Res. Int. 2015, 2015, 1–15. [126] Kumar, M. N. V. R.; Muzzarelli, R. A. A.; Muzzarelli, C.; Sashiwa, H.; Domb, A. J. Chitosan Chemistry and Pharmaceutical Perspectives. Chem. Rev. 2004, 104(12), 6017–6084. [127] Fernandez, J. G.; Ingber, D. E. Manufacturing of Large–Scale Functional Objects Using Biodegradable Chitosan Bioplastic. Macromol. Mater. Eng. 2014, 299(8), 932–938. [128] Moradi, S.; Barati, A.; Salehi, E.; Tonelli, A. E.; Hamedi, H. Preparation and Characterization of Chitosan Based Hydrogels Containing Cyclodextrin Inclusion Compounds or Nanoemulsions of Thyme Oil. Polym. Int. 2019, 68, I1891–1902. [129] Raphaël, K. J.; Meimandipour, A. Antimicrobial Activity of Chitosan Film Forming Solution Enriched with Essential Oils; an In Vitro Assay. Iran J. Biotechnol. 2017, 15(2), 111–119. [130] Li, Z.; Yang, F.; Yang, R. Synthesis and Characterization of Chitosan Derivatives with DualAntibacterial Functional Groups. Int. J. Bio. Macromol. 2015, 75, 378–387. [131] Croce, M.; Conti, S.; Maake, C.; Patzke, G. R. Synthesis and Screening of N-Acyl Thiolated Chitosans for Antibacterial Applications. Carbohydr. Polym. 2016, 151, 1184–1192. [132] Kumar, G. V.; Su, C. H.; Velusamy., P. Preparation and Characterization of KanamycinChitosan Nanoparticles to Improve the Efficacy of Antibacterial Activity against Nosocomial Pathogens. J. Taiwan Inst. Chem. Engrs. 2016, 65, 574–583. [133] Mohamed, N. A.; Fahmy, M. M. Synthesis and Antimicrobial Activity of Some Novel CrossLinked Chitosan Hydrogels. Int. J. Mol. Sci. 2012, 13, 11194–11209.

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[134] Hassan, M. A.; Omer, A. M.; Abbas, E.; Baset, W. M. A.; Tamer, T. M. Preparation, Physicochemical Characterization and Antimicrobial Activities of Novel Two Phenolic Chitosan Schiff Base Derivatives. Sci. Rep. 2018, 8, 1–14. [135] Mohamed, R. R.; Fekry, A. Antimicrobial and Anticorrosive Activity of Adsorbents Based on Chitosan Schiff’s Base. Int. J. Electrochem. Sci. 2011, 6, 2488–2508. [136] Yin, X.; Chen, J.; Yuan, W.; Lin, Q.; Ji, L.; Liu, F. Preparation and Antibacterial Activity of Schiff Bases from O-Carboxymethyl Chitosan and Para-Substituted Benzaldehydes. Polym. Bull. 2012, 68, 1215–1226. [137] Kumar, S.; Kumari, M.; Dutta, P. K.; Koh, J. Chitosan Biopolymer Schiff Base: Preparation, Characterization, Optical, and Antibacterial Activity. Int. J. Polym. Mater. Po. 2014, 63, 173–177. [138] Labib, R. M.; Ayoub, I. M.; Michel, H. E.; Mehanny, M.; Kamil, V.; Hany, M.; Magdy, M.; Moataz, A.; Maged, B.; Mohamed, A. Appraisal on the Wound Healing Potential of Melaleuca alternifolia and Rosmarinus L. Essential Oil-Loaded Chitosan Topical Preparations. PLoS One. 2019, 14(9), e0219561. [139] Sharma, R.; Rao, R.; Kumar, S.; Mahant, S.; Khatkar, S. Therapeutic Potential of Citronella Essential Oil: A Review. Curr. Drug Discov. Technol. 2019, 16(4), 330–339. [140] Tamer, T. M.; Hassan, M. A.; Omer, A. M.; Baset, W. M. A.; Hassan, M. E.; El-Shafeey, M. E. A.; Elding, M. S. M. Synthesis, Characterization and Antimicrobial Evaluation of Two Aromatic Chitosan Schiff Base Derivatives. Process Biochem. 2016, 51, 1721–1730.

Larry Kolopajlo

3 The UN sustainable development goals and nanochemistry: a critical review Abstract: This chapter presents a critical analysis of the United Nations sustainable development goals (UN SDGs). It then discusses those goals most relevant to the field of chemistry, focusing on pioneering advances at the convergence of the UN SDGs, green chemistry, and nanochemistry. This narrative will help educators better understand the relationship between green chemistry and the SDGs. Moreover, educators will learn how new advances in nanochemistry can help fulfill the SDGs allowing for the development of new pedagogic approaches in teaching the concept of sustainability. Keywords: nanochemistry, nanoparticles, nanotechnology, review, chemistry education, green chemistry, SDG, sustainable development goals, UN SDGs

3.1 Introduction Holistic, universal, paradigm shift, and inclusive involving a broad systems approach – all glowing terms delineating the United Nations sustainable development goals (SDGs) rolled out in 2015 [1]. But like a Rubik’s sphere puzzle wrapped around the Earth, they are just as complicated to unravel. They are promoted as guiding principles illuminating the pathway to a sustainable future, but are they really a quantum leap forward? Critical reports pertaining to SDGs are difficult to find. Yet, the goal of having citizen scientists should mandate critical thinking, reflection, and analysis rather than accepting SDGs as postulates. The chapter begins with an evaluative discussion of SDGs, and then demonstrates how science and technology, specifically chemistry, can help achieve a sustainable world. The seven SDGs that are most applicable to chemistry are then successively highlighted, providing examples of exciting breakthroughs in nanochemistry that will help address the scale of the challenge. The pros and cons of SDGs will also be noted.

Acknowledgments: The author is grateful to the Chemistry Department of Eastern Michigan University for supporting this work. Larry Kolopajlo, Chemistry Department, Eastern Michigan University https://doi.org/10.1515/9783110723960-003

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3.2 The SDGs The 17 SDGs address three major global problems broadly related to economic inclusion, the environment, and justice. On its website, the United Nations exhibits them as 17 equivocal, independent goals. However, as will be shown in another section of this chapter, any listing or linear representation of SDGs is simplistic because they are not merely a list of isolated goals but form a dynamic, collective, interdependent web, or network. Moreover, this author feels that SDGs 16 and 17 would better fit within a new category, designated global governance and finance, which oversees the administration and management of all the other SDGs. The author’s four major divisions with their corresponding UN SDG number are as follows: I. Social economic inclusion: no poverty (1), zero hunger (2), good health (3), clean water and sanitation (6), and sustainable cities (11). II. Protecting the environment: clean and sustainable energy (7), responsible consumption and production (12), climate change (13), life below water (14), and life on land (15). III. Social justice: quality education (4), gender equality (5), work and economic growth (8), industry and infrastructure (9), and reduced inequalities (10). IV. Global governance and global finance: peace and justice (16), and partnerships (17).

3.3 Deconstructing the SDGs 3.3.1 A critical look at the SDGs Toward the goal of educating responsible citizen scientists, in this section, the UN SDGs will be deconstructed. In this narrative, the term deconstructing means to critically circumspect the root structure of SDGs to make sense of their purpose and to determine what may be askew. When faced with the copious volume of SDG material published on the UN website, one is tempted to utter: “Where do I begin?” The author chooses to begin with the basic idea of vocabulary. Firstly, what percent of the world’s population understand what the term “sustainability” implies? Secondly, there is no agreement among scholars on one theory of sustainable development, let alone a measurable definition of the concept of sustainability. As a result, Hopwood [2] constructively criticized SDGs for their lack of clarity of meaning, and for consigning the definition of sustainability as being open to interpretation. Thirdly, beyond having no consensus on basic definitions, concepts, and theories, there are the issues of educating the world’s citizens on both vocabulary and concepts.

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Beyond the lack of clear, simple, quantifiable operational definitions, SDGs do not appear to be supported by peer-reviewed studies. For example, the International Council for Science and International Social Science Council [2] criticized the SDGs for being based on a “weak theoretical foundation.” Hopwood [3] argued that SDGs should have as their foundation basic principles grounded in human equity, such as the five principles proposed by Houghton [4]. Hopwood also commented that instead of focusing on a 10-year plan, the focus should instead be on long-term sustainability requiring sustainable livelihoods that link human equity to the environment. Consequently, it is unclear which theory should guide the implementation and study of SDGs. A dearth of knowledge regarding the SDGs thus exists because few published papers review and critically examine them. As a result, no scholarly consensus on a theoretical framework has been reached. A cursory reading of SDG targets reveals an issue related to involuted style. As an example, consider the Urgent Action Climate Action Target 13a [5] replicated below; it is a meandering hodgepodge of bureaucratic obfuscation: Implement the commitment undertaken by developed-country parties to the United Nations Framework Convention on Climate Change to a goal of mobilizing jointly $100 billion annually by 2020 from all sources to address the needs of developing countries in the context of meaningful mitigation actions and transparency on implementation and fully operationalize the Green Climate Fund through its capitalization as soon as possible.

In fact, in a report published by the International Council for Science [6], 71% of the 169 SDG targets were evaluated as being poorly defined, weak, or nonessential. On the other hand, SDG indicators are better written, with more clearly defined and measurable outcomes. Another problem with the SDGs, their targets, and indicators is that they are not prioritized. Yet it is intuitive that some SDGs should carry more weight than others. On a positive note, an analysis by the International Council for Science indicated that although the UN goals are interrelated, they are basically independent. Therefore, if one SDG fails, unlike a domino chain reaction, there would not be complete failure across the SDG network. Although rigorous assessments of SDGs are in scant supply, in 2018, Swain and Yang-Wallentin [7] published an in-depth analysis. The authors focused on the contradictory relationship between economic development and sustainability. They noted three major issues: 1. Inconsistencies exist between socioeconomic and environmentally sustainability goals. 2. Measuring and monitoring SDGs is a challenging task. 3. Pecuniary support is ambiguous, especially the 100 billion (USD) annual funds. The authors applied confirmatory and exploratory factor analysis to arrive at structural equation models to study causality between sustainable development and the

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three main SDG classes: economic inclusion, environmental protection, and social justice. They concluded that developed countries could optimize their success in achieving the SDGs by focusing on environmental and social factors. On the other hand, they also concluded that developing countries will optimize their success in achieving the SDGs by focusing on economic and social factors. Spaiser et al. [8] published a study exploring the conjecture that social–economic growth and environmental sustainability, as presented in the SDGs, are incompatible. In other words, economic growth attains socioeconomic SDGs but hinders attainment of environmental SDGs. They used dynamical modeling to identify factors that result in growth and concluded that investment in renewable energy, health programs and government will minimize conflict between incompatible SDGs.

3.3.2 The SDGs and professional scientific societies A few well-known scientific societies were examined to determine to what extent they show support for the UN SDGs. The American Chemical Society [9] appears to have embraced the SDGs the most. The American Physical Society [10] has an action center urging members to act on methane and climate change, but a search on the term “UN SDGs” yielded no results. The American Association for the Advancement of Science [11] appears to support the SDGs but no specific policy could be found. The NSTA [12] apparently does not have a position statement on SDGs, although there are many links to sustainability on their website. The Geological Society of America [13] only has position statements supporting action on clean energy, climate change, and coastal hazards.

3.3.3 The SDG index The SDG index [14] was created to aid countries in identifying priorities for early action, although the SDGs themselves do not appear to be prioritized in any way. It is a score that assesses each country’s achievement in meeting SDGs. Having integrated 17 SDGs and their 169 subgoals into a single index, the Sustainable Development Solutions Network (SDSN) publishes a yearly report. The SDG index first appeared in 2015 [15] presenting results for 34 countries. In 2020, SDSN [16] ranked its 193 UN member countries according to their sustainable development progress. Nordic countries like Sweden, Denmark, and Finland were at the top of the list while the USA, China, and India ranked 31st, 48th, and 117th, respectively.

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3.3.4 The SDGs and social democracy The lack of clarity, the presence of inconsistencies, and absence of an organized theoretical framework supporting the SDGs induces a state of cognitive dissonance in the reader, compelling a scholarly search for an underlying theme. It is suggested that SDGs were designed to promote the form of government known as social democracy, and there are two major pieces of evidence supporting this conjecture. Firstly, the United Nations itself indicates that social democracy plays an important role in SDGs. On the UN website UN SDG: Learn is a course titled Sustainable Development: The Post Capitalist Order [17]. Within a postcapitalist society, there exists a binary division of workers into either knowledge or service categories. However, postcapitalist government frameworks can take many forms, for example, as socialist or communist states. The well-known management professor Peter Drucker wrote extensively about Post-capitalism [18] and predicted that society would make the transformation in 2020. The UN course titled Sustainable Development: The Post-Capitalist Order is a diatribe against capitalism, and inexplicably ignores its successes. Moreover, the course outline does not point out the UN’s own failures, let alone the many injustices tied to socialism or communism. Module 4 ties capitalism to injustice and concludes by presenting “The Social Democratic idea.” Module 5 then introduces SDGs. The second strand of evidence comes from the SDG index. The government framework called “social democracy” is theoretically in a transition state between capitalism and socialism; free market capitalism coexists alongside a welfare state, with the end state eventually becoming social democracy. It has become known as the Nordic model because it has been influential in Northern and Western Europe. Is it a coincidence that the top ten countries on the 2020 SDG Index are from Western and Northern Europe? Thus, two data points link the SDGs to social democracy, which begs the question: Were the SDGs constructed as a strategy to guide the world toward social democracy? The conjecture is made that the SDG index rewards socialist behavior: the more a country models social democracy, the higher is its SDG index. This is why the author created a fourth class on global governance and finance to separate fiscal management from goals that elevate those living in poverty.

3.4 Nanotechnology 3.4.1 The SDGs and nanotechnology Technology plays an important role in achieving each of the 17 SDGs and their 169 targets. Recognizing that new and undiscovered technologies are necessary if the

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ambitious 2030 Agenda for Sustainable Development is to be reached, in the UN Global Sustainable Development Report – 2016 (GSDR) [19], 14 key objectives related to technology are identified. Moreover, one emerging technology cited in the report was nanotechnology, which is a crucial, novel technology having the potential to benefit many sectors of the economy. To meet SDGs, nanotechnology advances are needed in many areas, like nanomaterial solar cells, organic and inorganic nanoparticles (NPs), the desalination of water, wastewater treatment, conducting polymers, and nanoimprint lithography. These technologies would be primarily employed in chemical, electronics, agricultural, medical, and pharmaceutical sectors of the economy. The terms “nanoscience” and “nanotechnology” refer to the broad array of applied scientific methods that study matter in the form of NPs, whose smallest sizes in one dimension are on the scale of one billionth of a meter, and whose upper size range limit is less than 100 nm. The SI prefix nano derives from the Latin nanos, literally meaning “a dwarf.” In 1947, the Union Internationale de Chimie introduced it as an SI prefix having the numerical value of one billionth. The American physicist Richard Feynman is credited with envisioning nanotechnology as a future science laden with possibilities. In his 1959 lecture, “There’s Plenty of Room at the Bottom: An Invitation to Enter a New Field of Physics,” Feynman delineates “the problem of manipulating and controlling things on a small scale,” in molecular biology, electronics, computer science, nanomachines, and chemical synthesis [20]. At this tiny dimension, particles exhibit unique and unpredictable behaviors that result in physical properties and chemical reactivities that are different from those found in bulk matter for three reasons: (a) they can exhibit effects governed by quantum mechanics, (b) very high surface areas, and (c) shape effects. The results are unusual and novel applications which in some cases are neither Newtonian nor quantum mechanical. The field has grown exponentially over the last 20 years as scientists unravel the mystery of how to use these particles in everyday living. This chapter takes a deep dive into showing how nanotechnology is related to fulfilling the SDGs related to chemistry.

3.4.2 The SDGs and nanoparticles NPs are widely used in over 1,600 consumer products [21, 22] spanning the fields of agriculture, chemistry, cosmetics, electronics, fuel additives, medical equipment, paints, pigments, plastics, sporting goods, and textiles. But with little known about their health and environmental consequences, how can they help guide the world to a sustainable future, and how can society prepare for their negative impacts? While taking advantage of their present uses, researchers must understand how size, shape, stability, chemical composition, and environmental fates all play a role in the risks presented to the environment and to the health and safety of humans.

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Further, researchers must understand and weigh the benefits of NPs against their risks. Their life cycles and environmental fates need studying, especially if they are at the forefront of technology. Industries should consider safe(r)-by-design strategies in research and development (R&D), and in the production of nanomaterials.

3.4.3 The SDGs and chemistry According to the American Chemistry Council [23], more than 95% of all manufactured US goods involve chemistry. However, very few industrial processes have made the transition to green chemistry. Moreover, the American Chemical Society [24] has decided that the following seven SDSs, aligned with green chemistry, are deemed most relevant to chemistry: 2: Zero hunger (social economic inclusion) 3: Good health and well-being (social economic inclusion) 6: Clean water and sanitation (social economic inclusion) 7: Affordable and clean energy (protecting the environment) 9: Industries, innovation, and infrastructure (social justice) 12: Responsible consumption and production (protecting the environment) 13: Climate action (protecting the environment) Unraveling the interdependent nature of the above goals results in a very complicated web that would be difficult to model without the use of iterative numerical computing. For example, treating each of the 17 SDGs as an independent node would require modeling 136 independent links between them. Moreover, assuming that the published 169 SDG targets are linked would require modeling 14,196 relationships. In fact, just treating the seven chemistry SDGs as independent nodes would require modeling a minimum of 41 links. However, the scenario would be more complicated because of the expectation of feedback loops. As an example of how the SDGs interact, consider the qualitative modeling of the interactions between responsible production and consumption (SDG 12) and the others in the chemistry group. Optimizing SDG 12 would have positive effects on SDGs 3, 6, 7, and 13. In other words, optimizing the consumption and production of chemicals through green chemistry would curb waste resulting in cleaner water (6) and the utilization of less energy (7), resulting in less greenhouse gases and having a positive effect on health (3) and climate action (13). As another example of these complex interactions, consider how meeting SDG 2 on zero hunger can cause negative effects on SDGs 3, 6, 7, 13, and 14 [25]: zero hunger (goal 2) requires increased land-based agricultural food production, which requires more clean water (6), more chemicals such as pesticides and fertilizers, and more energy in the form of fossil fuel such as gasoline (7). This need for increased agriculture then results in soil depletion and contamination, while runoff pollutes waterways.

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Moreover, by consuming more energy in the form of fossil fuels to make fertilizers and run gasoline engines, goal 13 (climate change) is undermined by the production of greenhouse gases. A weakened climate then has a negative effect on plant production. To mitigate such negative effects of zero hunger, responsible consumption and production (goal 12) and innovation in industry (goal 9) can certainly help.

3.5 Nanochemistry and the seven chemistry SDGs This narrative will now delve into the seven SDGs associated with chemistry, and specifically cover nanochemistry.

3.5.1 Zero hunger (SDG 2) 3.5.1.1 Ending hunger through the SDGs As of the beginning of 2022, the world population has reached 7.87 billion and is predicted to reach 8 billion by 2025, and 11 billion by 2100 [26]. World population is currently increasing at a rate of about 1% per year. As a result, there will be commensurate increases in demand for food. Increased food production will require increased agricultural production, especially in developing countries. The field of agriculture is broad, and in this section, only plant agriculture is addressed. In its 2020 Discovery Report [27] titled “Feeding the World,” the American Chemical Society identifies the biggest hurdles to feeding a world where crop productivity is negatively affected by climate change. The report then identifies ways of protecting the future harvest through more research on plant root systems, disease resistance, supercharging photosynthesis, and strengthening plants to survive soil extremes. The report includes sketches on 20 companies with promising futures in futuristic farming. Nanotechnology appears to be totally absent in this report. However, nanoagriculture can help alleviate hunger by increasing food production. This goal can be achieved by using nanosubstances as fertilizers, through protecting plants from harmful pests, monitoring growth, sensing diseases, and reducing waste. Of the eight targets associated with ending hunger, chemistry will most likely influence and have the most impact on targets 2.3 and 2.4. 2.3: double the agricultural productivity and incomes of small-scale food producers, in particular women, indigenous peoples, family farmers, pastoralists and fishers, including through secure and equal access to land, other productive resources and inputs, knowledge, financial services, markets and opportunities for value addition and non-farm employment. 2.4: ensure sustainable food production systems and implement resilient agricultural practices that increase productivity and production, that help maintain ecosystems, that

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strengthen capacity for adaptation to climate change, extreme weather, drought, flooding and other disasters that progressively improve land and soil quality.

It is obvious that the field of chemistry can boost agricultural production by finding new, environmentally friendly synthetic fertilizers, pesticides, insecticides, and herbicides. Traditional fertilizers applied in bulk quantities have major drawbacks such as large losses due to runoff or leaching, with subsequent accumulation in waterways where they cause, for example, algae blooms and water eutrophication. They can also pollute groundwater and decrease mineral content in soils, eventually diminishing soil fertility. Toward the goal of overcoming problems associated with traditional agricultural chemicals, alleviating world hunger, and producing sustainable agriculture in the face of climate change and rising populations, nanochemistry is finding pioneering and widespread use. Chen et al. [28] have published a positive assessment of what this new technology can bring to agricultural science.

3.5.1.2 Nanofertilizers Novel nanofertilizers [29] encapsulate plant nutrients within NPs coated with a thin protective substance that is engineered to undergo controlled degradation. For example, a nitrogen nanofertilizer was prepared by coating urea, a nitrogen source, with hydroxyapatite [30]. But sometimes polymer films are used instead. In another study, Boehm et al. [31] reported on an encapsulation method used to deliver an insecticide to plants. Such highly technically manufactured nanofertilizers have been called “smart delivery systems” because their release kinetics can be set to a predetermined slow and steady rate to cover, for example, a 40-day period [32]. They also have extremely high surface areas, making them more evenly distributed within the soil. Another advantage of smart delivery systems is that they can conserve the amount of fertilizer used by delivering a smaller amount to a target. However, they have not been well studied to determine what harmful effects they might have on the environment or on plants themselves. Nanofertilizers have also been engineered to deliver these essential soil micronutrients: Cu, Fe, Mn, Si, and Zn [33]. For example, copper and zinc are essential plant micronutrients, being utilized in plant protein and enzymatic biochemistry. Their deficiencies can lead to several kinds of plant diseases resulting in reduced growth and yields. Colloidal solutions of copper oxide and zinc oxide NPs have been used in nanofertilizers to deliver these micronutrients to agricultural soils. One advantage of their use is that concentrations of these micronutrients can be adjusted to provide exactly what the plants require. Traditionally, copper sulfate has been used to deliver copper to soil. However, this delivery method is a rather

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blunt instrument because copper accumulates deep in the soil. Nanocopper nutrients use less copper, helping to alleviate this copper contamination problem. However, unforeseen problems have arisen. Margenot et al. [34] reported that CuO NPs can cause root thickening and root water transport problems in lettuce and carrots. Moreover, ZnO and CuO from nonagricultural applications may also accumulate in agricultural soil. Their subsequent fates and chemical reactions are unknown. At high concentrations, these metals are especially dangerous, but such concentrations may never be reached through plant bioaccumulation. Some authors [35] suggest that environmental toxicology studies be made before ZnO and CuO are allowed widespread use. In fertilizers, carbon NPs [36] such as graphene, fullerenes, and graphene oxides have shown, among other benefits, increased seed germination rates, seed growth, and plant growth. However, they bioaccumulate in plants, eventually causing phytotoxicity. If they accumulate in plants, then would the plants be inedible?

3.5.1.3 Nanopesticides and nanoherbicides The terms “nano-enabled herbicides” (NEH) and “nano-enabled pesticides” (NEP) refer to any product whose crop protection efficacy (usefulness, functionality, or risk assessment) is boosted by way of a nanomaterial. NEPs [37] are now entering agricultural markets because they offer many advantages over conventional pesticide products. Among the advantages are safer but improved pest control at reduced application rates, and better formulations with easier delivery and application. At present, NEPs utilize inert or active ingredients that act as a matrix to carry the active ingredient. Inert hydrogel nanocarriers consist of hydrophilic polymers, such as sodium alginate or polyacrylate, that absorb large amounts of water, swell, and aid in the dispersion of a pesticide or herbicide in soils. They enhance the solubility, transport, and delivery of a pesticide or herbicide in water. To overcome the challenges of suspending and stabilizing active ingredients, rheological modifiers prevent sedimentation during transport and storage, but adjusting viscosity for easy flow during application. Pereira et al. [38] studied the application of the herbicide atrazine encapsulated in poly(epsilon-caprolactone) NPs used as a carrier system. They found that herbicide activity increased while herbicide genotoxicity decreased compared to free release of atrazine. Moreover, the mobility of atrazine in the soil also decreased. NP formulations effectively controlled agricultural weeds. In a review of 78 published papers, Kah et al. [39] critically accessed nanopesticides and nanofertilizers against their conventional analogues and found a 20–30% gain in efficacy. NP formulations studied have involved polymers, inorganics (silica, TiO2), and emulsions. However, the study was largely inconclusive in isolating

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benefits and risks. Deficiencies in published studies included environmental fate, adequate controls, and quality assurance.

3.5.1.4 Nanosensors Biosensors designed smart for agriculture have been reviewed [40]. Moreover, as new analytical nanosensors are developed, they too will be applied to agriculture to detect harmful compounds. Smart sensors have been applied to organophosphorus pesticides, such as diazinon, malathion, and parathion, which are effective but highly toxic phosphate esters that act as acetylcholinesterase inhibitors. They can cause death by damaging the central and peripheral nervous systems. More specifically, they irreversibly inhibit the activity of the enzyme acetylcholinesterase resulting in the lethal buildup of the neurotransmitter acetylcholine in the body. Although they rapidly degrade in the environment through hydrolysis, small quantities can bioaccumulate. It is therefore important to monitor their persistence in the field. To detect organophosphorus pesticides, a fluorescent nanosensor [41] using carbon quantum dots in conjunction with an MnO2 nanosheet quencher was reported. The detection limit was 0.015 ng/mL. Another fast and sensitive detection method [42] for organophosphorus pesticides utilized a silicon quantum dot sensor and consecutive reactions. Two sensor reactions take place. In the first reaction, acetylcholine chloride reacts with acetylcholinesterase forming choline. In the next stage, choline oxidase catalyzes the breakdown of choline into betaine and hydrogen peroxide, which quenches photoluminescence in the silicon quantum dot sensor. However, when a pesticide enters the sensor, the activity of acetylcholinesterase is inhibited causing a decrease in hydrogen peroxide, which in turn causes an increase in photoluminescence. In other applications, nitrate [43] and humidity sensors [44, 45] have been designed.

3.5.2 Good health (3) 3.5.2.1 The health SDGs Of the 13 targets related to good health and well-being [46], the following six targets directly relate to chemistry: 3.3: End epidemics: AIDS, tuberculosis, malaria and tropical diseases; combat hepatitis, water-borne diseases and other communicable diseases. 3.4: Reduce by one third premature mortality from non-communicable diseases through prevention and treatment; promote mental health and well-being. 3.5: Strengthen the prevention and treatment of substance abuse, including narcotic drug abuse and harmful use of alcohol.

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3.8: Achieve universal health coverage, financial risk protection, access to quality health-care services, and safe, effective, quality and affordable medicines and vaccines. 3.9: Reduce the number of deaths and illnesses from hazardous chemicals and air, water and soil pollution and contamination. 3.b: Support the research and development of vaccines and medicines for the communicable and non-communicable diseases that primarily affect developing countries, provide access to affordable essential medicines and vaccines, in accordance with the Doha Declaration on the TRIPS Agreement and Public Health, which affirms the right of developing countries to use to the full the provisions in the Agreement on Trade-Related Aspects of Intellectual Property Rights regarding flexibilities to protect public health, and, in particular, provide access to medicines.

3.5.2.2 Nanomedicine In 2007, Duncan [47] and Murthy [48] published a review of medical advances using NPs. Two general but important applications involved using NPs in drug delivery systems and in medical imaging. In medical imaging, NPs in the form of quantum dots [49, 50] have been used for site-specific imaging of tumors, blood vessels, and lymph nodes. Their advantages are that they are noninvasive, site specific, and provide higher intensity images. However, when a quantum dot is being used for internal medicine, it is important for the surface coating to be biocompatible with its environment. Therefore, one of the challenges facing quantum dot medical applications is growing concern over their toxicity, as discussed in Hardman’s recent review [51]. For example, Cd2+ ions can induce cytotoxicity because they bind to thiol groups in proteins, damaging them to the point where they collapse. They have been used in magnetic resonance imaging to detect cancer [52]. Nanomaterials are also being used in medicine for drug delivery [53, 54]. Traditional treatments of cancer, for example, involve one of three choices: surgery, radiation, or chemotherapy; and each treatment involves damage to the surrounding tissue and substantial recovery times. Chemotherapeutics offer challenges in solubility and stability. Moreover, other disadvantages of chemotherapy include serious side effects such as fatigue, nausea, pain, hair loss, and appetite loss. New advances in cancer therapy, utilize NPs as drug carriers. Nanosubstances deliver drugs to the targeted tumors, with less cytotoxicity to surrounding cells. In polymer-based drug delivery, a biocompatible and water-soluble polymer such as polyethylene glycol (PEG) [55] is emulsified to the size of NP dimensions, in this case, less than 100 nm in diameter. Antitumor drugs are then encapsulated within the PEG-coated NP. Nanomicelles are also being used to house anticancer drugs and carry them to tumor sites. For example, Wei et al. [56] created 10 nm supramolecular nanomicelles based on amphiphilic dendrimers containing a hydrophobic lipid segment and a hydrophilic dendritic polymer component. The presence of micelles was verified through transmission electron microscopy. Not only was drug solubility increased, but the

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dendrite structure harbored large voids enabling the delivery of high drug payloads to targets. More specifically, researchers used their nanomicelles to deliver doxorubicin, a highly toxic anticancer drug that stops cancer cell growth by blocking the enzyme topoisomerase 2, essential for cancer cell growth and division. A major advantage of this system was that drug resistance was overcome by way of reduced toxicity, increased cellular uptake, and decreased drug loss. The small size of nanomicelles evaded excretion through the kidneys, as well as sequestration in the spleen. As a result, the chemotherapeutic drug penetrated deeper into tumors and accumulated at higher concentrations. The drug release profile was also very favorable. In another groundbreaking application, Stevens et al. [57] developed a nanocatalyst sensor to detect colorectal cancer in mice through a molecular signature. Ultrasmall gold nanoclusters were employed in NP–protein complexes as in vivo imaging, and the results are being observed in a colorimetric urine test. More specifically, the team of scientists tied gold nanoclusters to the protein neutravidin using peptides. The linkages could be cleaved by matrix metalloproteinases whose presence shows an early warning sign of cancer. In unhealthy cancer-bearing mice, the matrix metalloproteinases tore away the gold nanoclusters from the carrier proteins. The gold nanoclusters were then excreted. When the urine samples were treated with 3–3ʹ, 5–5ʹ-tetramethylbenzidine and hydrogen peroxide, a blue compound formed as a result of a gold NP (AuNP)-catalyzed reaction between 3–3ʹ,5–5ʹ-tetramethylbenzidine and hydrogen peroxide. The nanosensors were totally eliminated through hepatic and renal excretion within 4 weeks of injection. Moreover, no signs of toxicity were found. Although the system has yet to be optimized for testing in human subjects, this development can have a huge impact on the medical diagnoses of cancer, especially in developing countries where medical treatment is lacking.

3.5.2.3 Health and safety of nanoparticles Industrial applications of NPs have grown exponentially since the 1990s. In 2015, the EU funded NMP-DeLA (the Nanomaterial Project Deployment in Latin America) in line with the UN Millennium development goals [58]. Project goals included spurring collaboration with European countries in nanotechnology, with special focus on water, energy, and health. Moreover, the project explored new market opportunities, education, and training. The Organization for Economic Co-operation and Development (OECD) [59] has generated many tools and models to serve as risk assessment and management tools to assess the occupational, consumer, and environmental exposure to nanomaterials. The genotoxicity of manufactured nanomaterials has also been investigated by the OECD [60]. The concern is that the huge surface areas of NPs may increase reactivity compared to traditional macroscopic materials. This enhanced activity potentially interferes with genotoxicity assay elements.

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President George W. Bush formally created the National Nanotechnology Initiative (NNI) in 2003, although President Bill Clinton initiated it in 1998. The NNI is an R&D that oversees 20 agencies and departments. Its goals are to maintain US leadership, promote commercialization, support research, expand the workforce, and ensure responsible development. The NNI [61] is a US government R&D initiative involving the nanotechnology-related activities of 20 departments and independent agencies. The NNI consists of the individual and cooperative nanotechnologyrelated activities of federal agencies with a range of research and regulatory roles and responsibilities. In order to scientifically assess the risks and potential negative impacts of nanotechnology on health and the environment, the first official NNI strategy of nanotechnology-related environmental, health, and safety research was established in 2008 [62]. The Nanotechnology Environmental and Health Implications Working Group summarized progress on determining the health, safety, and environmental effects of NPs through 2014 [63]. The first objective was to develop measurement tools to determine the physical and chemical properties of nanomaterials in various media. Physical determinations include physical dimensions, surface properties, and dispersion properties. Chemical properties include reactivities that depend on size, shape, and surface area. Moreover, life cycle studies were also initiated, but such investigations were in their infancy. In order to perform such studies, standard operating procedures and standard reference materials (SRMs) are necessary. To fill that gap, the National Institute of Standards and Technology (NIST) currently markets just a few SRMs [64] for purchase, among them being titanium dioxide, gold, single-walled carbon nanotubes, and polyvinylpyrrolidone-coated silver NPs. The present situation on the availability of SRM for nanomaterials is unfortunate. A second major initiative was launched to develop measuring tools to sample, detect, and monitor NPs in real-lab conditions. To meet this challenge, measurements involving mass, particle number, size distribution, and surface area would be made, requiring peer-reviewed analytical methods. One example of an NIST achievement was the development of a fluorescently labeled silicon NP reference material to be released in summer 2014 [65]. Another important objective was to find measuring tools that allowed the evaluation of biological responses to NPs. As a result of such studies, about 30 in vitro and in vivo assays [66] provided data on various classes of nanomaterials including those that were carbon-based and those based on metals. A fifth governmental objective was to quantitate the degradation and release of NPs through mechanical [67], photo-induced, hydrolytic mechanisms [68], and through incineration [69]. Moreover, how humans interact with NPs through social interactions, spraying, inhalation have been studied [70]. In January 2017, the EPA issued a statement requiring the review of nanoscale materials under the Toxic Substances Control Act (TSCA). This regulation requires one-time reporting and recordkeeping of health and safety information, and existing exposure to nanoscale chemicals. Moreover, companies importing, manufacturing,

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or processing nanoscale substances must supply the EPA with the following information: chemical identity, existing health and safety data, exposure and release information, production volumes, and information regarding manufacturing and processing methods. The EPA is currently studying the following kinds of NPs for their environmental safety [71]: nanosilver, carbon nanotubes, cerium dioxide, titanium dioxide, iron, and micronized copper. Some US regulations currently exist that address many nanoscale materials because NPs are treated as “chemical substances” which fall under the TSCA [72]. However, there is growing concern that the transmission of NPs into the environment may cause harm to ecosystems. Moreover, scientists need to understand that exposure to NPs may harm humans in both occupational and nonoccupational environments.

3.5.2.4 Sources There are both natural and anthropogenic sources of NPs. Among the natural atmospheric sources include large-scale events such as dust storms, volcanic activity, forest fires, wind erosion, and interstellar dust [73]. There are also natural biological sources such as bacteria and fungi. Anthropogenic sources may be classified as intentional or nonintentional, and as stationary or nonstationary. Examples of unintentional stationary sources are garbage, municipal waste incineration, the manufacturing industry, and the coal and mining industries as well [74]. For example, the construction industry unintentionally generates NPs from cement and lime. Other man-made unintentional sources include consumer products like textiles and cosmetics. On the other hand, unintentional mobile sources include exhaust emissions from internal combustion engine vehicles. Intentional man-made stationary sources include NPs used as fertilizers and pesticides.

3.5.2.5 Airborne dusts and explosion hazards Karim, bin Munir, and Yasin [75] have written an authoritative article on nanotechnology and international law [76]. The authors provide important information on how the United Nations, European nations, the USA, and Canada are working together to construct NP product registers and regulations tied to risk and exposure assessment. This work is just beginning with a long road ahead. Moreover, the United Nations Institute for Training and Research offers many safety training courses related to nanotechnology. One safety consideration is that NPs can form airborne dusts which represent a respiration hazard. Moreover, it would be possible for such dusts to form explosion hazards. The term “dust explosion” refers to the swift and instantaneous combustion of finely divided particles suspended in the air within an enclosed location. In 2019,

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The National Fire Protection Association issued a report [77] attempting to identify and evaluate combustion properties and fire and explosion hazards related to NPs. One question to be answered was: at what particle size do combustion properties change? One result was that concentration is a major factor in determining the severity of an NP dust explosion. Three types of particles were investigated: aluminum. magnesium, and carbon nanotubes. The most explosive size range for aluminum was 100–200 nm. The minimum explosive concentration (MEC) in g/m3 varied with particle size, being about 40 g/m3 at 50 nm, and then rising to about 80 g/m3 in the 100–1,000 nm size range. For magnesium, the MEC increased exponentially as particle size increased from 5 to 10,000 nm. Less information was available for carbon nanotubes. However, it was found that explosion risks increased with smaller particle size. Sodium bicarbonate is the most popular suppressing agent. However, manufacturing sites should focus on dust collection mechanisms with safe storage containers to prevent explosions. NPs may deposit in respiratory tracts. The occupational exposure to NPs such as carbon nanotubes by inhalation may result in pulmonary inflammation and fibrosis [78]. For example, titanium dioxide (TiO2), which has many commercial applications (e.g., paint, paper, cosmetics, and food), can be produced and used in varying particle sizes, including the nanoscale particle sizes (90% recovery of the impure water as compared to existing reverse osmosis processes that typically recover closer to 50% of the saline water with energy inputs of 4–6 kWh/m3 [49]. Alternative switchable solvents such as 1-cyclohexylpiperidine have been explored [50], although despite leading to improved membrane stability and the switch being more readily reversible [51], is limited by being substantially more expensive than DMCHA.

Figure 5.4: Schematic of the purification of water using switchable solvents (SPS) as forward osmosis draw solutions. Reprinted from Desalination, Volume 312, Stone et al., Switchable polarity solvents as draw solutes for forward osmosis, page 127, Copyright (2013), with permission from Elsevier [48].

5.2.3 Goal 7: affordable and clean energy The primary aim of goal 7 is to ensure access to affordable, reliable, sustainable, and modern energy. Alternative solvents contribute to goal 7 through two different approaches. The first is an indirect approach whereby alternative solvents reduce the energy input for chemical processes, for example, by reducing the temperature required to perform a reaction. This reduces energy demand, increasing the availability of existing energy for others. We will not focus on this indirect approach here although it can make a useful contribution toward this goal and toward tackling climate change by reducing the use of energy produced by nonrenewable sources. The other method is where the alternative solvent is actively incorporated in energy materials that are used to produce, convert, or store energy. With respect to energy materials, ILs are leading alternative solvent candidates due to their inherent electrical conductivity, low volatility, and flammability as well as their electrochemical stability which leads to them being less hazardous than many current electrolyte materials [52, 53]. ILs have been explored for applications with a range

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of energy materials including electrolytes for batteries, solar cells, fuel cells, thermoelectrochemical cells, supercapacitors, and actuators as well as in the preparation of electrode materials for such applications [54, 55]. A few selected examples of the role that ILs can play in these energy devices are highlighted below. Solar energy is predicted to play a significant role as an energy source of the future given its abundant supply and ability to be produced near the site of use, allowing for the decentralization of distribution networks [56]. While bulk solar energy production is dominated by large module installation based on semiconducting silicon, alternative means of producing solar energy can fill different niches [57]. This includes dye-sensitized solar cells (DSSCs) which utilize a dye as a chromophore with electron–hole separation accomplished by adsorbing the dye onto a semiconductor with appropriate band gap positions and through the use of a redox mediator in the electrolyte (Figure 5.5). The effective electron–hole separation enables these devices to operate under diffuse light conditions, including harnessing photons from indoor lighting [57]. One of the major limitations to DSSCs is the volatility of the liquid electrolyte, which frequently contains acetonitrile. Its evaporation leads to changes in electrolyte concentration over time if the DSSC is not completely hermetically sealed and can create flammability risks [58]. TiO2

Dye

Redox electrolyte Glass / FTO

Platinum (Pt) / Glass

Figure 5.5: DSSC schematic and operation. DSSCs consist of a transparent conducting oxide such as fluorine-doped tin oxide (FTO) on glass, a nanoparticle photoanode (in this case titania covered in a monolayer of sensitizing dye), a hole-conducting electrolyte, and a platinum-coated glass. Reprinted from Solar Energy, volume 115, Su’ait et al., Review on polymer electrolyte in dyesensitized solar cells (DSSCs), page 454, Copyright (2015), with permission from Elsevier.

ILs have been proposed as alternative electrolytes for DSSCs in an attempt to circumvent the issues of electrolyte evaporation and flammability [59–61]. One of the earliest examples of an IL as a DSSC electrolyte was [C6C1im]I which served as both the electrolyte and the counterion for the I−/I3− redox mediator [61]. Advances

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in IL electrolyte systems have included the use of binary mixtures of less viscous ILs with those featuring an I− anion and the separate use of simple I− salts in less viscous ILs, such as [C2C1im][N(CN)2], which allowed efficiencies to increase over 5% [59, 60]. Further modifications to IL electrolyte systems have had limiting returns with the greatest efficiencies observed to date being 8.4% [62, 63] for pure IL electrolytes. Much higher efficiencies, up to over 14% [64], have been observed for mixtures of ILs with organic solvents due to the reduced viscosity of these compositions and their optimization with respect to redox potential. This emphasizes that efficient DSSCs based on ILs are possible but pure IL-based electrolyte systems require substantial further advances in electrolyte design. Energy storage devices are becoming increasingly important with the rapid development of portable electronic devices and the fluctuations inherent to renewable energy production. Li-ion batteries are a ubiquitous feature of many modern devices, with the electrolytes used in these batteries consisting of Li salts dissolved in organic solvents such as ethylene carbonate and diethyl carbonate [65, 66]. These organic solvents are flammable and lead to issues with side reactions at the cathode and transition metal ion migration from the cathode materials [67–69]. Therefore, ILs provide an opportunity for electrolytes with high thermal and electrochemical stability to be developed. IL selection for Li-ion batteries is partially governed by the electrochemical stability of the ions, in particular the reductive stability of the cation and the oxidative stability of the anion. For cations, this has meant that [CnC1pyrr]and [CnC1pip]-based ILs have been increasingly explored as these are less easily reduced than ILs based on imidazolium or pyridinium cations. Anion selection is often confined to fluorinated anions such as [BF 4]−, [PF6]−, fluorosulfonimide ([FSI]−), and [NTf2]− to facilitate low-viscosity ILs and the oxidative stability of the anion. This has led to [C4C1pyrr][NTf2], [C3C1pyrr][NTf2], and [C3C1pip][NTf2] or their [FSI]− variants being often used as exemplar electrolytes for Li-ion batteries [70–72]. [C3C1pyrr][FSI] has even been used as an electrolyte for Li-ion batteries onboard a satellite [73] and has also been successfully demonstrated as an electrolyte for Na-ion batteries [74]. The use of IL electrolytes for batteries has been commercialized with companies such as Nohms Technologies and Gelion employing IL electrolytes for Li-ion batteries and Zn–Br batteries, respectively. This development highlights that IL electrolytes are beginning to make the transition from academic research labs to contribute directly to the UN SDGs by being incorporated into viable energy storage technologies. ILs can also be advantageous for the preparation of novel inorganic materials including electrodes, electrocatalysts, and photocatalysts which have potential for use in future energy applications. Many of these materials can be prepared by ionothermal synthetic methods involving the use of ILs as reaction media [54]. For example, ILs have been used to prepare novel electrodes for Li-ion battery applications. For the anode, the IL can act as an N, S, and B containing precursor to dope carbonaceous materials. This can fine-tune the physicochemical properties of carbon materials

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including an improvement in the electronic conductivity and electroactivity of the electrode as well as providing improved long-term stability in comparison to conventional lithium anodes [75]. ILs containing anions with high nitrogen content such as [N(CN)2]− have been found to be particularly suitable for these applications. ILs have also been used to fabricate cathodes. For example, a single-phase LiFePO4 has been developed as a cathode material from FeC2O4 · 2H2O or FeCl2 and LiH2PO4 precursors using ILs as reaction media. The use of ILs enabled the cathode to be synthesized at temperatures as low as 250 °C, and it was found that the morphology of the resultant materials could be rationally controlled by the choice of IL ions [76, 77]. The ionothermal synthesis approach has also been applied to numerous other materials with energy applications including catalysts for fuel cells, photochemical and photoelectrochemical water splitting, and in the preparation of semiconductors for DSSCs [78]. New approaches for ionothermal synthesis have been recently developed using DESs although these methods are less well developed than those featuring ILs [79]. These demonstrate the indirect role that alternative solvents can play in developing new, more sustainable energy sources by providing highperformance methods for the manufacturing of new materials rather than necessarily being incorporated into the final device. ILs can therefore contribute directly to energy production, storage, and the preparation of new energy materials with only a few of the myriad possible examples highlighted above. A major issue with the deployment of ILs for these technologies is often cost. Overcoming this typically relies on substantial performance improvements in the resultant technology or the blending of the IL with other liquids to optimize performance while minimizing cost. The commercialization of devices featuring ILs, discussed above, highlights that such obstacles can be overcome and that it is likely that energy devices relying on alternative solvent technologies will very soon make significant direct contributions to this UN SDG.

5.2.4 Goal 12: responsible consumption and production The goal of responsible consumption and production aims to ensure sustainable consumption and production patterns. A major aim of this goal is to greatly increase the proportion of waste material that can be reused rather than being disposed of. In addition to reducing the quantity of waste generated, this helps reduce the need to exploit natural resources for further production. Alternative solvents have been explored for the recycling of waste material, with the aim of leveraging the unusual interactions present in many of these solvents to create new, more effective chemical processes. Waste plastics are environmentally problematic due to their persistence and potential for adverse health effects, with micro- and nanoplastics becoming widespread in the environment [80]. This has led to an urgent need to develop new methods for

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the recycling and reuse of plastics to reduce their production and minimize the loss of waste plastics to the environment. While the optimal approach would involve reusing existing plastic without processing, this is not always possible due to the presence of colorants and other additives. The next best alternative for some plastics involves their depolymerization to regenerate the monomer, allowing new plastics with the desired properties for a given application to be prepared by the repolymerization [81]. Unfortunately, traditional plastic depolymerization reactions occur at high temperatures using high pressures which affect the economic viability of the process and lead to significant energy usage. Kamimura et al. explored the use of ILs for the depolymerization of nylon 6 into caprolactam, the monomer used for its production [81]. Nylon 6 is one of the most common polymers used with its total annual production of nearly 5 million tons [82]. Kamimura et al. found that optimal conditions for the depolymerization involved using the IL [C3C1pyrr][NTf2] with an N,N-dimethylaminopyridine catalyst at 300 °C for 6 h (Scheme 5.3), with 86% conversion into the monomer being achieved. After separating the monomer from the IL, the IL could be reused 5 times giving similar yields between 75% and 90% each time [81]. The advantage of using the IL is that the depolymerization does not require the use of high-pressure equipment given the nonvolatility of the solvent, and the reaction is done at a lower temperature than those requiring sub- or supercritical water [83]. The unique solubilizing properties of ILs have also been employed to separate polycotton blends, mixed fibers commonly used in textiles [84]. The use of [(C1 = C2)C1im] Cl enabled the selective dissolution of cotton after heating to 80 °C for 6 h, allowing the undissolved polyester to be recovered. The addition of water to the IL facilitated the quantitative regeneration of cotton fibers. Further developments to this approach include the use of [DBNH][OAc] (DBNH = 1,5-diazabicyclo(4.3.0)non-5-enium) as a solvent to enable the dry-jet wet spinning of waste cotton fibers. This led to fibers with improved mechanical properties relative to virgin cotton fibers and with higher degrees of crystallinity than fibers spun using an organic solvent approach featuring N-methylmorpholine N-oxide [85]. These results highlight the ability of these novel solvents to facilitate material recovery and recycling, or upcycling, from wastes. About 6–8 million tons of crustacean shell waste is produced annually [86]. ILs and DESs have been explored as novel solvents for the extraction of chitin from this waste [87–89]. The dissolution of chitin utilizes DESs containing urea or thiourea while similar ILs to those that are able to dissolve cellulose tend to be successful at dissolving chitin, such as [C4C1im]Cl and [C4C1im][OAc] [90]. This biopolymer can then be valorized into useful N-containing platform chemicals. Alternatively, chitin itself can be used as a fiber or deacetylated to form chitosan which is already being used in the production of materials for tissue engineering and stem cell technologies [91]. These examples highlight how alternative solvents, particularly ILs and

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Scheme 5.3: Treatment of nylon in an IL at 300 °C to convert it to its monomeric lactam [81].

DESs, can be leveraged to separate and reconstitute fibers as part of recycling processes to help facilitate their reuse. Switchable solvents have been explored as part of the polystyrene recycling process. One of the major limitations of polystyrene recycling is the low density of polystyrene foam which leads to significant energy requirements for transport given the foam can be up to 90% air. Polystyrene foam was found to dissolve in DMCHA, which led to the trapped air being released [23]. Switching the solvent to its polar form through the addition of water and CO2 led to the precipitation of polystyrene which had reduced in volume by a factor of 15 due to the release of the trapped air. Unfortunately, significant amounts of amine (8 wt%) were found in the reconstituted polystyrene but this does demonstrate the potential to use these switchable solvent systems as low-energy upgrading systems for polymer recycling. The idea of using switchable solvents for polymer recycling was further examined by Samori et al. [92]. They investigated the use of DMCHA for the separation of multilayered food packaging consisting of low-density polyethylene (LDPE) and aluminum. DMCHA was able to selectively extract the LDPE from aluminum, with the LDPE being recovered when DMCHA was switched to its hydrophilic form. Removing CO2 by gently heating the solution allowed for the regeneration and recycling of the solvent. Over 99% of the aluminum could be recovered alongside up to 93% of the LDPE. Life cycle analysis of this approach highlighted that the switchable solvent process led to more favorable environmental outcomes than other disposal or recycling methods including landfill, pyrolysis, and the use of formic acid treatment, emphasizing the potential benefits of this approach.

5.2.5 Goal 13: climate action UN SDG 13 climate action refers to the need to take urgent actions to combat climate change and its impacts. As one of the significant areas of focus for developing alternative solvents is to move away from solvents derived from fossil carbon, this is an area where these solvents can make a substantial contribution. Bio-based solvents have been developed to remove the need for fossil carbon in the preparation of solvents. Two different approaches to the development of bio-based solvents have been taken. The first aims to prepare existing solvents from bio-based

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inputs, allowing them to be used as direct substitutes for the existing solvent. Many of these bio-based solvents have been prepared with the intention of their use as biofuels. For example, bio-ethanol is already produced at large scale from the fermentation of sugars from hydrolyzed corn starch or sugarcane [93]. Being produced from a biobased source does not necessarily guarantee reduced greenhouse gas emissions from the manufacturing and end-of-life stages. Hence, a life cycle analysis of bio-ethanol has been performed which identified that sugarcane, sugar beet and corn-based ethanol more than halves the number of CO2 equivalent emissions compared to ethanol prepared from fossil fuel sources [94]. Other common solvents that have been prepared commercially from bio-based sources include acetone, other aliphatic alcohols such as 1-butanol and 2-propanol, ethyl acetate, tetrahydrofuran, and acetic acid [6, 95]. Rather than developing new bio-based methods for preparing existing solvents, another approach has been used to develop entirely new solvents from bio-based sources. Feedstocks such as cellulose have been targeted due to the potential to link these production processes to emerging biorefineries based on lignocellulosic biomass, avoiding the need for competition with arable land currently used for food production [96]. 2-Methyltetrahydrofuran (2-MeTHF), γ-valerolactone (GVL), and dihydrolevoglucosenone, also known as cyrene, are three solvents of particular interest as bio-based alternatives that can be prepared from cellulose (Scheme 5.4). 2-MeTHF and GVL can both be prepared from levulinic acid which in turn can be obtained from the depolymerization of cellulose and conversion of the resultant hexoses, often through furfural or 5-hydroxymethylfurfural (HMF) intermediates. Cyrene

Scheme 5.4: Preparation of GVL and 2-MeTHF from levulinic acid [98].

Scheme 5.5: Preparation of cyrene from cellulose.

is obtained by the hydrogenation of levoglucosenone which can be obtained directly from the acid-catalyzed depolymerization of cellulose (Scheme 5.5) [97]. 2-MeTHF has found application as an alternative to tetrahydrofuran, with 2-MeTHF being less volatile and less water miscible leading to superior properties for many

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applications in addition to producing only 3% of the life cycle CO2 emissions of tetrahydrofuran [99]. GVL and cyrene have been proposed as replacements for polar aprotic solvents such as DMF, DMSO, and NMP. These represent some of the more hazardous and expensive solvents used in the chemical industry. The major limitation of the new bio-based solvents, particularly GVL and cyrene, is their cost although technoeconomic analysis of potential industrial-scale processes have found that their production cost could be reduced to around US $3/kg in both cases [3] which is comparable to more expensive solvents currently on the market such as DMF. Other bio-based alternative solvents including bio-based ILs and DES have also been explored to avoid issues associated with petrochemical inputs although these have not been as thoroughly developed to date [6, 100, 101]. Alternative solvents have also been used to reduce the energy associated with chemical processes, minimizing the need for greenhouse gas emitting energy production. One of the leading examples of this lies in the main concept underlying switchable solvents, particularly SHSs. The ability of SHSs to change polarity upon addition of CO2 and water allows reaction products or extracts to self-separate from the switched solvent through precipitation or the formation of an immiscible oil. The target can then be easily separated by filtration, avoiding the need for energy-intensive distillation to remove the solvent, saving considerable amounts of energy which may be produced from fossil fuel inputs [23]. If distillation is not required, then neither is the need for a volatile solvent. Eliminating volatile solvent use mitigates against direct atmospheric emissions of these solvents and reduces incidental solvent loss as well as improving the safety of the process. A major contribution alternative solvents can make toward supporting climate action is through their role in implementing future biorefineries. Alternative solvents such as ILs and DESs have shown great potential at being able to solubilize without derivatization, otherwise intractable biopolymers including cellulose, lignin, and chitin [102, 103]. This has been used as a basis for the fractionation of lignocellulosic biomass, a process for which multiple approaches have been explored [104–106]. One of the earliest approaches was the direct dissolution of cellulose using the IL [C2C1im] [OAc]; however, this process is not water tolerant. Additionally, the IL can dissolve multiple lignocellulosic components leading to relatively poor selectivity for the fractionation, and the IL is likely to be prohibitively expensive if used at a scale [106, 107]. An alternative approach was developed using a solution of [C2C2C2N][HSO4] in water which selectively removed lignin and hemicellulose from Miscanthus, while cellulose remains largely untouched, allowing for its ease of separation from the raw biomass [104]. The cost of preparing this IL has recently been estimated as $0.78/kg, less than commonly used organic solvents, highlighting the economic viability of this approach [108]. The ability of ILs to solubilize biopolymers has also led to them being explored as media for their valorization. The dissolution of biopolymers to form a homogeneous solution at high concentrations and at lower temperatures than in organic solvents assists the reactivity of these compounds, and the lack of volatility of ILs

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Scheme 5.6: Synthesis of 3A5AF from chitin.

avoids the need for high-pressure equipment. For example, kinetic studies of the formation of 3-acetamido-5-acetylfuran (3A5AF), a compound proposed as a N-containing platform chemical [109–111], from chitin (Scheme 5.6) identified that the reaction in the IL [C4C1im]Cl proceeded more than 5 times faster at 180 °C compared to the reaction in NMP at 215 °C [112]. Similar results have been observed for the valorization of cellulose and hemicellulose into platform chemicals such as HMF and furfural, where ILs have typically been found to offer more rapid reaction rates at lower temperatures than conventional organic solvents [113, 114]. These examples highlight how alternative solvents can address climate change by enabling solvents with higher carbon footprints to be substituted, facilitating lower energy processes and by helping to provide platform technologies for future biorefineries. Further work toward the commercialization and implementation of these efforts will help contribute to achieving the aims of UN SDG 13.

5.2.6 Goals 14 and 15: life below water and life on land The aims of goals 14 and 15 are to conserve and sustainably use the oceans and terrestrial ecosystems including the use of marine resources, combating desertification and halting biodiversity loss. Alternative solvent contributions to these aims include those previously discussed at addressing the impacts of climate change, minimizing waste and new technologies for the purification of wastewater. Further contributions in this area include the development of solvents that are inherently biodegradable to avoid long-term harm for marine and terrestrial environments, methods for utilizing biomass sources as chemical and biofuel feedstocks that have less competition for land than existing approaches, and carbon capture technologies to minimize the impact of CO2 on ocean acidification. A key aim of green chemistry is to develop processes using chemicals that are not hazardous to humans and the environment and break down after use. The 10th principle of green chemistry is to design chemical products to break down to innocuous substances after use so that they do not accumulate in the environment [115]. Hence, for alternative solvents to be considered to be green solvents, they need to be readily biodegradable and not accumulate. This is readily achieved for bio-based solvents such as

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cyrene, 2-MeTHF, and GVL and is an essential part of their development [116–118]. The biodegradation of other alternative solvents such as ILs and DES is less clear, in part due to the thousands of possible combinations that can and have been produced. The broad range of anions and cations in principle allows ILs and DESs to be designed with optimized technological properties and reduced environmental hazard but relies on the development of an understanding of their toxicity and biodegradability. Several studies have now been published on the biodegradability of ILs. Stolte et al. investigated the biodegradability of IL anions and found that IL anions containing carbon chains are more likely to undergo microbial degradation as they can act as a carbon source [119]. Linear alkyl sulfates display excellent biodegradability, with linear alkylsulfonates and alkylbenzene sulfonates showing slightly reduced biodegradation efficiency while remaining ultimately biodegradable. The added benefit of alkyl sulfates is that when combined with an IL cation they still retain their biodegradability (Figure 5.6) [120, 121]. Stolte et al. did not measure the biodegradability of linear alkyl sulfonates and alkylbenzene sulfonates once they had been combined with IL cations; however, they were not as biodegradable as linear alkyl sulfates to begin with [119]. ILs based on biomaterials have also been made using biodegradable anions such as lactate, tartrate, acetate, propionate, benzoate, fumarate, and succinate (Figure 5.6) [119]. While these do not guarantee that the IL will completely biodegrade, they do increase the likelihood of biodegradation that occurs. On the other hand, fluorine-

Figure 5.6: The biodegradability of IL anions (reproduced from Stolte et al. [119]).

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containing IL anions such as [OTf]− and [NTf2]− (Figure 5.6) are resistant to biological degradation [122]. Inorganic moieties such as halides, [BF4]−, and [PF6]− also do not biodegrade due to the absence of oxidizable carbon (Figure 5.6), although most halides are not inherently environmentally problematic due to their abundance in ocean environments. This shows that not all IL anions are biodegradable but there is the potential to design ILs using anions that are. As the number of known biodegradable anions increases, as does the scope for designing ILs that are able to be optimal for a given application and break down on release into the environment. Stolte also looked at the biodegradability of cations. This included a range of N-alkyl-pyridinium compounds where it was found that their biodegradability increased with the carbon side chain length (Figure 5.7). This was also true for IL cations containing the imidazolium headgroup, although the degree of degradation was innately higher for the pyridinium compounds [119].

Figure 5.7: The biodegradability of N-substituted pyridinium compounds [119].

Pyridinium derivatives such as N-(ethoxycarbonyl)-pyridinium cation and N-alkylated nicotinic acid ester are classified as readily biodegradable (Figure 5.8) [119]. However, N-butyl-nicotinamide was significantly less biodegradable compared to the N-butyl nicotinic acid ester after 28 days (30% as to 81%) (Figure 5.8) [119]. Stasiewicz et al. found that the biodegradability of N-alkoxymethyl-3-hydroxy-pyridinium salts also improved slightly when increasing the length of the carbon side chain but only up to 11 carbon atoms as a subsequent decrease in biodegradability was observed when 18 carbon atoms were present. This is most likely due to the increased toxicity of the octadecyl compound due to the ability of this chain to lyse cell membranes (Figure 5.8) [123]. Hence, the ability for IL cations to be biodegradable can be tuned upon selection of the core, functional group, and length of the carbon chain, with chains of moderate length being most readily biodegradable. Increasing the understanding of rational selection of biodegradable cations and anions allows for the selection of biodegradable ILs that will minimize harm for life on earth or water. Similar biodegradability concepts also apply to DESs, although many DESs already comprise components that are biodegradable. Surprisingly this does not necessarily guarantee that the DES will readily biodegrade, with one study identifying that DESs based on choline acetate with glycerol or ethylene glycol HBDs are less biodegradable than [C4C1im][BF4] despite the latter containing a fluorinated anion [124]. However, DESs based on urea or acetamide and choline chloride were found to be readily biodegradable, as were DESs based on amino acid anions [125]. These represent a small subclass of the

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Figure 5.8: The biodegradability of ester-, amide-, and ether-substituted pyridinium compounds [119].

totality of DESs, so considerable further work is required, particularly as new compounds are developed, to assess their ability to degrade in the environment before these compounds are used on a large scale. This helps to ensure that replacing any volatile organic solvents with these compounds works to minimize the long-term impact of any waste on marine and terrestrial ecosystems. With the shift away from petrochemical inputs, there is an urgent need for new sources of biofuels and chemicals. One of the major issues associated with many of these proposed sources is the requirement that they grow on arable land which will exacerbate deforestation and compete with food production. One proposed alternative that avoids the need for large-scale land use is the harvesting of microalgae. Microalgae have high oil contents relative to plant-based biomass, up to 80% of dry weight for some species of algae [126]. Algae can also rapidly grow in areas unsuitable for other forms of agriculture in non-potable water [127]. A major limitation of using algae for biofuel production is the energy costs associated with drying the biomass which is necessary for oil extraction using conventional organic solvents. To address this issue, switchable solvents have been explored for the extraction of lipids from algae [127–130]. While different approaches have been attempted, the one that most completely leverages the advantages of switchable solvents involves

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the use of DMCHA for the extraction of Scenedesmus dimorphus [130]. In this extraction process, the switched, hydrophilic form of DMCHA was used to extract proteins and carbohydrates from the algae, with close to 50% of each being successfully isolated. The addition of heat under a bubbling nitrogen atmosphere was used to generate the hydrophobic DMCHA which could then remove 93% of lipids from the algae which self-separate on the addition of CO2. This process means that the switchable solvent fulfills two separate roles, as a hydrophobic and hydrophilic extraction solvent, with the solvent being able to be recycled between each by the addition of small amounts of heat or through the addition of CO2. The order of these processes can also be reversed with the hydrophobic extraction being performed first. This demonstrates the potential of switchable solvents to achieve good extraction efficiencies of oil from algal biomass without the need for rigorous drying of the algae. If this process is implemented, it would assist in minimizing the use of terrestrial ecosystems for biomass production, reducing the associated deforestation that would ensue. Outside of the issues associated with climate change, increased levels of atmospheric CO2 result in the acidification of the world’s oceans. Estimates are that the pH of the world’s oceans has decreased by 0.1 since the pre-industrial era [131], which represents a roughly 30% increase in H3O+ concentration. This is projected to increase and have significant impacts on marine environments including the dissolution and loss of diversity within carbonate reefs, thinning of shellfish shells, and an increase in toxic algal blooms. Such effects will lead to functional consequences for marine ecosystems. One of the approaches to reduce the release of CO2 into the atmosphere, thereby minimizing its effect on marine environments, is to capture CO2 at its source of production. Current approaches to CO2 capture feature aqueous solutions of amines such as monoethanolamine and suffer from the corrosiveness and reactivity of the amine as well as the high energy cost of regeneration imposed by the thermal mass of water [132]. Alternative solvents that do not require the addition of water, particularly ILs, have been explored for CO2 capture as they have the potential to significantly reduce regeneration costs. Early approaches explored the dissolution of CO2 in ILs as it was found that ILs possessed high CO2 selectivities and solubilities, particularly [CnC1im][NTf2] ILs [133, 134]. Unfortunately, reliance on solubility alone requires CO2 pressures that are too high for practical CO2 capture and yields capacities below what would be required to be economically feasible. The next generation of ILs involved those that were functionalized with amines to try to achieve the benefits of amine reactivity with CO2 and the nonvolatility and inherent solubility of CO2 in ILs. ILs that are functionalized for a particular application are known as task-specific ILs. Some of the task-specific IL classes explored for CO2 capture are summarized in Figure 5.9. The major downside to the initial amine-functionalized ILs that were explored was an increase in viscosity as they led to the formation of a dicationic ammonium salt and a zwitterionic carbamate following the reaction with

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CO2 [135, 136]. To mitigate the increase in viscosity, aprotic heterocyclic anions were developed that facilitated direct reaction with CO2 to afford a carbamate anion, leaving the polarity of the IL largely unchanged [137]. Similar strongly basic anions using the imidazolide anion have also been explored for these applications [138]. These latter systems are able to capture more than 1 mole of CO2 per mole of IL, highlighting their capacity, and could be regenerated almost completely by heating to 110 °C. Capacities of over 2 moles of CO2 per mole of IL were able to be obtained using lysine-based ILs (Figure 5.9(d)), taking advantage of the two separate amines present alongside the inherent solubility of CO2 inside the IL. Complete dissolution did require 24 h, highlighting the need for improved kinetics as well as thermodynamic stability of these systems. While the industrial implementation of these IL systems requires greater insight into their environmental consequences and consideration of the economics involved, it does demonstrate how ILs can contribute to capturing CO2 with the aim of reducing the impacts of ocean acidification as well as the other consequences of increasing levels of CO2 in the atmosphere.

Figure 5.9: Examples of ILs functionalized for CO2 capture. (a) Amine-functionalized ILs, (b) aprotic heterocyclic anions, (c) superbase ILs, and (d) lysine-based ILs. Counterions are not shown for clarity.

5.2.7 Other goals The preceding discussion aims to highlight key contributions that can be made by alternative solvents toward addressing the UN SDGs. This list is by no means exhaustive, and certainly there are substantial contributions that have not been covered here and goals with overlapping aims that could be assisted by alternative

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solvent technologies. For example, improved energy technologies can assist the design of more efficient transportation systems toward goal 11 aiming to create more sustainable cities and communities. Likewise, these emerging technologies are likely to lead to the generation of new employment opportunities and economic growth. Facilitating a shift away from inequitably distributed oil resources toward biomass feedstocks that can be grown on marginal land would improve global inequality, provide pathways out of poverty, and achieve more equitable economic growth by creating value-added global primary industry opportunities. This would directly support achieving the aims of goals 1, 8, and 10. Avoiding the need to compete with arable land for these inputs would benefit goal 2 as well by ensuring that agricultural land can be focused on food production. Certainly none of this will be achievable without global partnerships (goal 17) to help develop the science underpinning these technologies and find appropriate avenues for their ultimate implementation. Alternative solvents present exciting opportunities to solve major challenges in sustainability; however, many of these applications are not simply drop-in replacements for existing solvent-based processes. This means there is a need to share expertise from those with an advanced understanding of alternative solvents with those that have in-depth knowledge of the desired application for these solvents, including those with the ability to enable the ultimate translation of these new technologies into industrial applications.

5.3 Conclusions and outlook Alternative solvents such as bio-based solvents, ILs, DESs, and switchable solvents have been rapidly emerging over the past decade as potential solutions to many sustainability challenges. As has been highlighted here, many of the ongoing active areas of research in alternative solvents are directly applicable to the UN SDGs. This ranges from their use in designing new approaches to water purification through to the development of energy storage and conversion technologies and processes toward the development of biorefineries employing feedstocks that can be obtained without competing with food sources. The major challenges for the future implementation of these alternative solvent approaches vary significantly based on the nature of the new process and the alternative solvent. For example, the use of bio-based solvents obtained from renewable solvents as replacements for existing petrochemical solvents is primarily limited by production cost and scale as the processes themselves are not greatly affected. On the other hand, the implementation of IL, DES, or switchable solvent extractions requires a more significant change to the underlying processes given their nonvolatility. ILs and DESs also present some additional complications due to the

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sheer variety of different compounds within each class. While this presents exciting opportunities for scientific endeavor, it increases the burden of evidence that needs to be obtained to ensure that each unique compound is safe to human health and the environment before they are involved in any large-scale processes. This latter consideration means that ILs, DESs, and switchable solvents are likely to be of greatest value for applications that necessitate the development of entirely new processes, such as biorefinery development, rather than smaller scale drop-in applications. These considerations highlight the multitude of ways that alternative solvents may contribute to the design of a more sustainable future.

References [1]

McNaught, A. D.; Wilkinson, A. Compendium of Chemical Terminology; Blackwell Science Oxford, United Kingdom 1997, vol. 1669. [2] Li, C. J.; Trost, B. M. Green Chemistry for Chemical Synthesis. Proc. Natl. Acad. Sci. U. S. A. 2008, 105(36), 13197–13202. doi: https://doi.org/10.1073/pnas.0804348105. [3] Clarke, C. J.; Tu, W. C.; Levers, O.; Bröhl, A.; Hallett, J. P. Green and Sustainable Solvents in Chemical Processes. Chem. Rev. 2018, 118(2), 747–800. doi: https://doi.org/10.1021/acs. chemrev.7b00571. [4] Clark, J. H.; Tavener, S. J. Alternative Solvents: Shades of Green. Org. Process Res. Dev. 2007, 11(1), 149–155. doi: https://doi.org/10.1021/op060160g. [5] Thenrajan, R. S.; Katari, O.; Ruhina Rahman, S. N.; Pawde, D. M.; Goswami, A.; Chandira, R. M.; Shunmugaperumal, T. Neoteric Solvents for the Pharmaceutical Industry: An Update. Drug Discov. Today. 2021, 00(00), 1–10. doi: https://doi.org/10.1016/j.drudis.2021.03.005. [6] Calvo-Flores, F. G.; Monteagudo-Arrebola, M. J.; Dobado, J. A.; Isac-García, J. Green and BioBased Solvents. Top. Curr. Chem. 2018, 376(3), 1–40. doi: https://doi.org/10.1007/s41061018-0191-6. [7] Sherwood, J.; De Bruyn, M.; Constantinou, A.; Moity, L.; McElroy, C. R.; Farmer, T. J.; Duncan, T.; Raverty, W.; Hunt, A. J.; Clark, J. H. Dihydrolevoglucosenone (Cyrene) as a Bio-Based Alternative for Dipolar Aprotic Solvents. Chem. Commun. 2014, 50(68), 9650–9652. doi: https://doi.org/10.1039/c4cc04133j. [8] Hernáiz, M. J.; Alcántara, A. R.; García, J. I.; Sinisterra, J. V. Applied Biotransformations in Green Solvents. Chem. – A Eur. J. 2010, 16(31), 9422–9437. https://doi.org/https://doi.org/ 10.1002/chem.201000798 [9] Horváth, I. T. Solvents from Nature. Green Chem. 2008, 10(10), 1024–1028. doi: https://doi. org/10.1039/b812804a. [10] Seddon, K. R.; Stark, A.; Torres, M.-J. Influence of Chloride, Water, and Organic Solvents on the Physical Properties of Ionic Liquids. Pure Appl. Chem. 2000, 72(12), 2275–2287. [11] Earle, M. J.; Esperança, J. M. S. S.; Gilea, M. A.; Lopes, J. N. C.; Rebelo, L. P. N.; Magee, J. W.; Seddon, K. R.; Widegren, J. A. The Distillation and Volatility of Ionic Liquids. Nature. 2006, 439(7078), 831–834. doi: https://doi.org/10.1038/nature04451. [12] Dean, P. M.; Pringle, J. M.; MacFarlane, D. R. Structural Analysis of Low Melting Organic Salts: Perspectives on Ionic Liquids. Phys. Chem. Chem. Phys. 2010, 12(32), 9144–9153. doi: https://doi.org/10.1039/c003519j.

120

[13] [14]

[15]

[16] [17]

[18]

[19] [20]

[21] [22] [23]

[24]

[25]

[26] [27]

[28]

[29]

Sahil D. Patel and Cameron C. Weber

Hallett, J. P.; Welton, T. Room-Temperature Ionic Liquids: Solvents for Synthesis and Catalysis. 2. Chem. Rev. 2011, 111(5), 3508–3576. doi: https://doi.org/10.1021/cr1003248. Weber, C. C.; Masters, A. F.; Maschmeyer, T. Structural Features of Ionic Liquids: Consequences for Material Preparation and Organic Reactivity. Green Chem. 2013, 15(10), 2655–2679. doi: https://doi.org/10.1039/c3gc41313f. Hansen, B. B.; Spittle, S.; Chen, B.; Poe, D.; Zhang, Y.; Klein, J. M.; Horton, A.; Adhikari, L.; Zelovich, T.; Doherty, B. W.; Gurkan, B.; Maginn, E. J.; Ragauskas, A.; Dadmun, M.; Zawodzinski, T. A.; Baker, G. A.; Tuckerman, M. E.; Savinell, R. F.; Sangoro, J. R. Deep Eutectic Solvents: A Review of Fundamentals and Applications. Chem. Rev. 2021, 121(3), 1232–1285. doi: https://doi.org/10.1021/acs.chemrev.0c00385. Smith, E. L.; Abbott, A. P.; Ryder, K. S. Deep Eutectic Solvents (DESs) and Their Applications. Chem. Rev. 2014, 114(21), 11060–11082. doi: https://doi.org/10.1021/cr300162p. Abbott, A. P.; Boothby, D.; Capper, G.; Davies, D. L.; Rasheed, R. K. Deep Eutectic Solvents Formed between Choline Chloride and Carboxylic Acids: Versatile Alternatives to Ionic Liquids. J. Am. Chem. Soc. 2004, 126(29), 9142–9147. doi: https://doi.org/10.1021/ ja048266j. Zhang, Q.; De Oliveira Vigier, K.; Royer, S.; Jérôme, F. Deep Eutectic Solvents: Syntheses, Properties and Applications. Chem. Soc. Rev. 2012, 41(21), 7108–7146. doi: https://doi.org/ 10.1039/c2cs35178a. Pollet, P.; Eckertabc, C. A.; Liotta, C. L. Switchable Solvents. Chem. Sci. 2011, 2(4), 609–614. doi: https://doi.org/10.1039/c0sc00568a. Jessop, P. G.; Mercer, S. M.; Heldebrant, D. J. CO2-Triggered Switchable Solvents, Surfactants, and Other Materials. Energy Environ. Sci. 2012, 5(6), 7240–7253. doi: https:// doi.org/10.1039/c2ee02912j. Jessop, P. G.; Heldebrant, D. J.; Li, X.; Eckert, C. A.; Liotta, C. L. Reversible Nonpolar-to-Polar Solvent. Nature. 2005, 436(7054), 1102. Vanderveen, J. R.; Durelle, J.; Jessop, P. G. Design and Evaluation of SwitchableHydrophilicity Solvents. Green Chem. 2014, 16(3), 1187–1197. Jessop, P. G.; Kozycz, L.; Rahami, Z. G.; Schoenmakers, D.; Boyd, A. R.; Wechsler, D.; Holland, A. M. Tertiary Amine Solvents Having Switchable Hydrophilicity. Green Chem. 2011, 13(3), 619–623. doi: https://doi.org/10.1039/c0gc00806k. Phan, L.; Chiu, D.; Heldebrant, D. J.; Huttenhower, H.; John, E.; Li, X.; Pollet, P.; Wang, R.; Eckert, C. A.; Liotta, C. L.; Jessop, P. G. Switchable Solvents Consisting of Amidine/Alcohol or Guanidine/Alcohol Mixtures. Ind. Eng. Chem. Res. 2008, 47(3), 539–545. doi: https://doi. org/10.1021/ie070552r. Vinci, D.; Donaldson, M.; Hallett, J. P.; John, E. A.; Pollet, P.; Thomas, C. A.; Grilly, J. D.; Jessop, P. G.; Liotta, C. L.; Eckert, C. A. Piperylene Sulfone: A Labile and Recyclable DMSO Substitute. Chem. Commun. 2007, 14, 1427–1429. doi: https://doi.org/10.1039/b616806j. Nations, U. Transforming Our World: The 2030 Agenda for Sustainable Development. N. Y. United Nations Dep. Econ. Soc. Aff. 2015. Daly, H. E. Allocation, Distribution, and Scale: Towards an Economics that Is Efficient, Just, and Sustainable. Ecol. Econ. 1992, 6(3), 185–193. https://doi.org/https://doi.org/10.1016/ 0921-8009(92)90024-M Costanza, R.; Daly, L.; Fioramonti, L.; Giovannini, E.; Kubiszewski, I.; Mortensen, L. F.; Pickett, K. E.; Ragnarsdottir, K. V.; De Vogli, R.; Wilkinson, R. Modelling and Measuring Sustainable Wellbeing in Connection with the UN Sustainable Development Goals. Ecol. Econ. 2016, 130, 350–355. doi: https://doi.org/10.1016/j.ecolecon.2016.07.009. Atkinson, R.; Arey, J. Atmospheric Degradation of Volatile Organic Compounds. Chem. Rev. 2003, 103(12), 4605–4638. doi: https://doi.org/10.1021/cr0206420.

5 Alternative solvents and the UN sustainable development goals

121

[30] Khan, F. I.; Ghoshal, A. K. Removal of Volatile Organic Compounds from Polluted Air. J. Loss Prev. Process Ind. 2000, 13(6), 527–545. [31] Darracq, G.; Couvert, A.; Couriol, C.; Amrane, A.; Thomas, D.; Dumont, E.; Andres, Y.; Le Cloirec, P. Silicone Oil: An Effective Absorbent for the Removal of Hydrophobic Volatile Organic Compounds. J. Chem. Technol. Biotechnol. 2010, 85(3), 309–313. https://doi.org/ https://doi.org/10.1002/jctb.2331 [32] Moura, L.; Moufawad, T.; Ferreira, M.; Bricout, H.; Tilloy, S.; Monflier, E.; Costa Gomes, M. F.; Landy, D.; Fourmentin, S. Deep Eutectic Solvents as Green Absorbents of Volatile Organic Pollutants. Environ. Chem. Lett. 2017, 15(4), 747–753. doi: https://doi.org/10.1007/s10311017-0654-y. [33] Yu, M.; Zeng, S.; Nie, Y.; Zhang, X.; Zhang, S. Ionic Liquid–Based Adsorbents in Indoor Pollutants Removal. Curr. Opin. Green Sustain. Chem. 2021, 27, 100405. doi: https://doi.org/ 10.1016/j.cogsc.2020.100405. [34] Abai, M.; Atkins, M. P.; Hassan, A.; Holbrey, J. D.; Kuah, Y.; Nockemann, P.; Oliferenko, A. A.; Plechkova, N. V.; Rafeen, S.; Rahman, A. A.; Ramli, R.; Shariff, S. M.; Seddon, K. R.; Srinivasan, G.; Zou, Y. An Ionic Liquid Process for Mercury Removal from Natural Gas. Dalt. Trans. 2015, 44(18), 8617–8624. doi: https://doi.org/10.1039/c4dt03273j. [35] Rajadurai, V.; Anguraj, B. L. Ionic Liquids to Remove Toxic Metal Pollution. Environ. Chem. Lett.2021, 19(2), 1173–1203. doi: https://doi.org/10.1007/s10311-020-01115-5. [36] Shamshina, J. L.; Kelley, S. P.; Gurau, G.; Rogers, R. D. Chemistry: Develop Ionic Liquid Drugs. Nature.2015, 528(7581), 188–189. doi: https://doi.org/10.1038/528188a. [37] Wang, H.; Gurau, G.; Shamshina, J.; Cojocaru, O. A.; Janikowski, J.; Macfarlane, D. R.; Davis, J. H.; Rogers, R. D. Simultaneous Membrane Transport of Two Active Pharmaceutical Ingredients by Charge Assisted Hydrogen Bond Complex Formation. Chem. Sci.2014, 5(9), 3449–3456. doi: https://doi.org/10.1039/c4sc01036a. [38] Pedro, S. N.; R. Freire, C. S.; Silvestre, A. J. D.; Freire, M. G. The Role of Ionic Liquids in the Pharmaceutical Field: An Overview of Relevant Applications. Int. J. Mol. Sci.2020, doi: https://doi.org/10.3390/ijms21218298. [39] Araújo, J. M. M.; Florindo, C.; Pereiro, A. B.; Vieira, N. S. M.; Matias, A. A.; Duarte, C. M. M.; Rebelo, L. P. N.; Marrucho, I. M. Cholinium-Based Ionic Liquids with Pharmaceutically Active Anions. RSC Adv.2014, 4(53), 28126–28132. doi: https://doi.org/10.1039/c3ra47615d. [40] Hough, W. L.; Smiglak, M.; Rodríguez, H.; Swatloski, R. P.; Spear, S. K.; Daly, D. T.; Pernak, J.; Grisel, J. E.; Carliss, R. D.; Soutullo, M. D.; Davis, J. H.; Rogers, R. D. The Third Evolution of Ionic Liquids: Active Pharmaceutical Ingredients. New J. Chem.2007, 31(8), 1429–1436. doi: https://doi.org/10.1039/b706677p. [41] Albadawi, H.; Zhang, Z.; Altun, I.; Hu, J.; Jamal, L.; Ibsen, K. N.; Tanner, E. E. L.; Mitragotri, S.; Oklu, R. Percutaneous Liquid Ablation Agent for Tumor Treatment and Drug Delivery. Sci. Transl. Med.2021, 13(580), eabe3889. doi: https://doi.org/10.1126/scitranslmed.abe3889. [42] Banerjee, A.; Ibsen, K.; Iwao, Y.; Zakrewsky, M.; Mitragotri, S. Transdermal Protein Delivery Using Choline and Geranate (CAGE) Deep Eutectic Solvent. Adv. Healthc. Mater.2017, 6(15), 1601411. https://doi.org/https://doi.org/10.1002/adhm.201601411 [43] Tanner, E. E. L.; Curreri, A. M.; Balkaran, J. P. R.; Selig-Wober, N. C.; Yang, A. B.; Kendig, C.; Fluhr, M. P.; Kim, N.; Mitragotri, S. Design Principles of Ionic Liquids for Transdermal Drug Delivery. Adv. Mater.2019, 31(27), 1901103. https://doi.org/https://doi.org/10.1002/adma. 201901103 [44] Misra, A.; Zambrzycki, C.; Kloker, G.; Kotyrba, A.; Anjass, M. H.; Franco Castillo, I.; Mitchell, S. G.; Güttel, R.; Streb, C. Water Purification and Microplastics Removal Using Magnetic Polyoxometalate-Supported Ionic Liquid Phases (MagPOM-SILPs). Angew. Chemie – Int. Ed.2020, 59(4), 1601–1605. doi: https://doi.org/10.1002/anie.201912111.

122

Sahil D. Patel and Cameron C. Weber

[45] Vázquez, M. M. P.; Vázquez, P. P.; Galera, M. M.; García, M. D. G. Determination of Eight Fluoroquinolones in Groundwater Samples with Ultrasound-Assisted Ionic Liquid Dispersive Liquid-Liquid Microextraction Prior to High-Performance Liquid Chromatography and Fluorescence Detection. Anal. Chim. Acta.2012, 748, 20–27. doi: https://doi.org/10.1016/j. aca.2012.08.042. [46] Rezaee, M.; Assadi, Y.; Milani Hosseini, M. R.; Aghaee, E.; Ahmadi, F.; Berijani, S. Determination of Organic Compounds in Water Using Dispersive Liquid-Liquid Microextraction. J. Chromatogr. A.2006, 1116(1–2), 1–9. doi: https://doi.org/10.1016/j. chroma.2006.03.007. [47] Freire, M. G.; Neves, C. M. S. S.; Marrucho, I. M.; Coutinho, J. A. P.; Fernandes, A. M. Hydrolysis of Tetrafluoroborate and Hexafluorophosphate Counter Ions in ImidazoliumBased Ionic Liquids. J. Phys. Chem. A.2010, 114(11), 3744–3749. doi: https://doi.org/ 10.1021/jp903292n. [48] Stone, M. L.; Rae, C.; Stewart, F. F.; Wilson, A. D. Switchable Polarity Solvents as Draw Solutes for Forward Osmosis. Desalination.2013, 312, 124–129. doi: https://doi.org/10.1016/ j.desal.2012.07.034. [49] Wendt, D. S.; Orme, C. J.; Mines, G. L.; Wilson, A. D. Energy Requirements of the Switchable Polarity Solvent Forward Osmosis (SPS-FO) Water Purification Process. Desalination.2015, 374, 81–91. doi: https://doi.org/10.1016/j.desal.2015.07.012. [50] Orme, C. J.; Wilson, A. D. 1-Cyclohexylpiperidine as a Thermolytic Draw Solute for Osmotically Driven Membrane Processes. Desalination.2015, 371, 126–133. doi: https://doi.org/10.1016/ j.desal.2015.05.024. [51] Reimund, K. K.; Coscia, B. J.; Arena, J. T.; Wilson, A. D.; McCutcheon, J. R. Characterization and Membrane Stability Study for the Switchable Polarity Solvent N,NDimethylcyclohexylamine as a Draw Solute in Forward Osmosis. J. Memb. Sci.2016, 501, 93–99. doi: https://doi.org/10.1016/j.memsci.2015.10.039. [52] Lewandowski, A.; Świderska-Mocek, A. Ionic Liquids as Electrolytes for Li-Ion Batteries-An Overview of Electrochemical Studies. J Power Sources. Elsevier 2009, 601–609. doi: https:// doi.org/10.1016/j.jpowsour.2009.06.089. [53] MacFarlane, D. R.; Forsyth, M.; Howlett, P. C.; Kar, M.; Passerini, S.; Pringle, J. M.; Ohno, H.; Watanabe, M.; Yan, F.; Zheng, W.; Zhang, S.; Zhang, J. Ionic Liquids and Their Solid-State Analogues as Materials for Energy Generation and Storage. Nat. Rev. Mater.2016, 1(2), 15005. doi: https://doi.org/10.1038/natrevmats.2015.5. [54] Macfarlane, D. R.; Tachikawa, N.; Forsyth, M.; Pringle, J. M.; Howlett, P. C.; Elliott, G. D.; Davis, J. H.; Watanabe, M.; Simon, P.; Angell, C. A. Energy Applications of Ionic Liquids. Energy Environ. Sci.2014, 7(1), 232–250. doi: https://doi.org/10.1039/c3ee42099j. [55] Watanabe, M.; Thomas, M. L.; Zhang, S.; Ueno, K.; Yasuda, T.; Dokko, K. Application of Ionic Liquids to Energy Storage and Conversion Materials and Devices. Chem. Rev.2017, 117(10), 7190–7239. doi: https://doi.org/10.1021/acs.chemrev.6b00504. [56] Erdiwansyah,; Mahidin,; Husin, H.; Nasaruddin; Zaki, M.; Muhibbuddin. A Critical Review of the Integration of Renewable Energy Sources with Various Technologies. Prot. Control Mod. Power Syst.2021, 6(1), doi: https://doi.org/10.1186/s41601-021-00181-3. [57] Freitag, M.; Teuscher, J.; Saygili, Y.; Zhang, X.; Giordano, F.; Liska, P.; Hua, J.; Zakeeruddin, S. M.; Moser, J. E.; Grätzel, M.; Hagfeldt, A. Dye-Sensitized Solar Cells for Efficient Power Generation under Ambient Lighting. Nat. Photonics.2017, 11(6), 372–378. doi: https://doi. org/10.1038/nphoton.2017.60. [58] Su’ait, M. S.; Rahman, M. Y. A.; Ahmad, A. Review on Polymer Electrolyte in Dye-Sensitized Solar Cells (DSSCs). Sol. Energy.2015, 115, 452–470. doi: https://doi.org/10.1016/j. solener.2015.02.043.

5 Alternative solvents and the UN sustainable development goals

123

[59] Wang, P.; Wenger, B.; Humphry-Baker, R.; Moser, J. E.; Teuscher, J.; Kantlehner, W.; Mezger, J.; Stoyanov, E. V.; Zakeeruddin, S. M.; Grätzel, M. Charge Separation and Efficient Light Energy Conversion in Sensitized Mesoscopic Solar Cells Based on Binary Ionic Liquids. J. Am. Chem. Soc.2005, 127(18), 6850–6856. doi: https://doi.org/10.1021/ja042232u. [60] Kawano, R.; Matsui, H.; Matsuyama, C.; Sato, A.; Susan, M. A. B. H.; Tanabe, N.; Watanabe, M. High Performance Dye-Sensitized Solar Cells Using Ionic Liquids as Their Electrolytes. J. Photochem. Photobiol. A Chem.2004, 164(1–3), 87–92. doi: https://doi.org/ 10.1016/j.jphotochem.2003.12.019. [61] Papageorgiou, N.; Athanassov, Y.; Armand, M.; Bonho⁁te, P.; Pettersson, H.; Azam, A.; Grätzel, M. The Performance and Stability of Ambient Temperature Molten Salts for Solar Cell Applications. J. Electrochem. Soc.1996, 143(10), 3099–3108. doi: https://doi.org/10.1149/ 1.1837171. [62] Talip, R. A. A.; Yahya, W. Z. N.; Bustam, M. A. Ionic Liquids Roles and Perspectives in Electrolyte for Dye-Sensitized Solar Cells. Sustain.2020, 12(18). doi: https://doi.org/ 10.3390/su12187598. [63] Bai, Y.; Zhang, J.; Wang, Y.; Zhang, M.; Wang, P. Lithium-Modulated Conduction Band Edge Shifts and Charge-Transfer Dynamics in Dye-Sensitized Solar Cells Based on a Dicyanamide Ionic Liquid. Langmuir.2011, 27(8), 4749–4755. doi: https://doi.org/10.1021/ la200156m. [64] Kakiage, K.; Aoyama, Y.; Yano, T.; Oya, K.; Fujisawa, J. I.; Hanaya, M. Highly-Efficient DyeSensitized Solar Cells with Collaborative Sensitization by Silyl-Anchor and Carboxy-Anchor Dyes. Chem. Commun.2015, 51(88), 15894–15897. doi: https://doi.org/10.1039/c5cc06759f. [65] Xu, K. Electrolytes and Interphases in Li-Ion Batteries and Beyond. Chem. Rev.2014, 114(23), 11503–11618. doi: https://doi.org/10.1021/cr500003w. [66] Erickson, E. M.; Markevich, E.; Salitra, G.; Sharon, D.; Hirshberg, D.; de la Llave, E.; Shterenberg, I.; Rosenman, A.; Frimer, A.; Aurbach, D. Review – Development of Advanced Rechargeable Batteries: A Continuous Challenge in the Choice of Suitable Electrolyte Solutions. J. Electrochem. Soc.2015, 162(14), A2424–A2438. doi: https://doi.org/10.1149/ 2.0051514jes. [67] Agubra, V.; Fergus, J. Lithium Ion Battery Anode Aging Mechanisms. Materials (Basel).2013, 6(4), 1310–1325. doi: https://doi.org/10.3390/ma6041310. [68] Ziv, B.; Borgel, V.; Aurbach, D.; Kim, J.-H.; Xiao, X.; Powell, B. R. Investigation of the Reasons for Capacity Fading in Li-Ion Battery Cells. J. Electrochem. Soc.2014, 161(10), A1672–A1680. doi: https://doi.org/10.1149/2.0731410jes. [69] Arora, P.; White, R. E.; Doyle, M. Capacity Fade Mechanisms and Side Reactions in Lithium‐ Ion Batteries. J. Electrochem. Soc.1998, 145(10), 3647–3667. doi: https://doi.org/10.1149/ 1.1838857. [70] Nádherná, M.; Reiter, J.; Moškon, J.; Dominko, R. Lithium Bis(Fluorosulfonyl)Imide-PYR14TFSI Ionic Liquid Electrolyte Compatible with Graphite. J. Power Sources.2011, 196(18), 7700–7706. doi: https://doi.org/10.1016/j.jpowsour.2011.04.033. [71] Simonetti, E.; Maresca, G.; Appetecchi, G. B.; Kim, G. T.; Loeffler, N.; Passerini, S. Towards Li(Ni0.33Mn0.33Co0.33)O2/Graphite Batteries with Ionic Liquid-Based Electrolytes. I. Electrodes’ Behavior in Lithium Half-Cells. J. Power Sources.2016, 331, 426–434. doi: https://doi.org/10.1016/j.jpowsour.2016.09.078. [72] Evans, T.; Piper, D. M.; Kim, S. C.; Han, S. S.; Bhat, V.; Oh, K. H.; Lee, S. H. Ionic Liquid Enabled FeS2 for High-Energy-Density Lithium-Ion Batteries. Adv. Mater.2014, 26(43), 7386–7392. doi: https://doi.org/10.1002/adma.201402103. [73] Yamagata, M.; Tanaka, K.; Tsuruda, Y.; Sone, Y.; Fukuda, S.; Nakasuka, S.; Kono, M.; Ishikawa, M. The First Lithium-Ion Battery with Ionic Liquid Electrolyte Demonstrated in

124

[74]

[75]

[76]

[77]

[78]

[79]

[80]

[81]

[82]

[83]

[84]

[85]

[86] [87]

[88]

Sahil D. Patel and Cameron C. Weber

Extreme Environment of Space. Electrochemistry.2015, 83(10), 918–924. doi: https://doi.org/10.5796/electrochemistry.83.918. Fukunaga, A.; Nohira, T.; Hagiwara, R.; Numata, K.; Itani, E.; Sakai, S.; Nitta, K. Performance Validation of Sodium-Ion Batteries Using an Ionic Liquid Electrolyte. J. Appl. Electrochem.2016, 46(4), 487–496. doi: https://doi.org/10.1007/s10800-016-0940-6. Paraknowitsch, J. P.; Thomas, A.; Antonietti, M.; Detailed, A. View on the Polycondensation of Ionic Liquid Monomers Towards Nitrogen Doped Carbon Materials. J. Mater. Chem.2010, 20(32), 6746–6758. doi: https://doi.org/10.1039/c0jm00869a. Recham, N.; Dupont, L.; Courty, M.; Djellab, K.; Larcher, D.; Armand, M.; Tarascon, J. M. Ionothermal Synthesis of Tailor-Made LiFePO4 Powders for Li-Ion Battery Applications. Chem. Mater.2009, 21(6), 1096–1107. doi: https://doi.org/10.1021/cm803259x. Recham, N.; Armand, M.; Tarascon, J. M. Novel Low Temperature Approaches for the EcoEfficient Synthesis of Electrode Materials for Secondary Li-Ion Batteries. Comptes Rendus Chim.2010, 13(1–2), 106–116. doi: https://doi.org/10.1016/j.crci.2009.05.003. Eshetu, G. G.; Armand, M.; Ohno, H.; Scrosati, B.; Passerini, S. Ionic Liquids as Tailored Media for the Synthesis and Processing of Energy Conversion Materials. Energy Environ. Sci.2016, 9(1), 49–61. doi: https://doi.org/10.1039/c5ee02284c. Cun, T.; Dong, C.; Huang, Q. Ionothermal Precipitation of Highly Dispersive ZnO Nanoparticles with Improved Photocatalytic Performance. Appl. Surf. Sci.2016, 384, 73–82. doi: https://doi.org/10.1016/j.apsusc.2016.05.008. Ganesh Kumar, A.; Anjana, K.; Hinduja, M.; Sujitha, K.; Dharani, G. Review on Plastic Wastes in Marine Environment – Biodegradation and Biotechnological Solutions. Mar. Pollut. Bull.2020, 150(May 2019), 110733. doi: https://doi.org/10.1016/j.marpolbul.2019.110733. Kamimura, A.; Yamamoto, S. An Efficient Method to Depolymerize Polyamide Plastics: A New Use of Ionic Liquids. Org. Lett.2007, 9(13), 2532–2535. doi: https://doi.org/10.1021/ ol070886c. Wood, L. Global Nylon Market Analysis and Outlook 2020-2027 – Nylon 6 Volumes Will Reach 5.3 Million Tons by 2027, despite COVID-19 – ResearchAndMarkets.Com. Business Wire.2020. Kronholm, J.; Vastamäki, P.; Räsänen, R.; Ahonen, A.; Kartonen, K.; Riekkola, M. L. Thermal Field-Flow Fractionation and Gas Chromatography-Mass Spectrometry in Determination of Decomposition Products of Expandable Polystyrene after Reactions in Pressurized Hot Water and Supercritical Water. Ind. Eng. Chem. Res.2006, 45(9), 3029–3035. doi: https://doi.org/ 10.1021/ie058058f. De Silva, R.; Wang, X.; Byrne, N. Recycling Textiles: The Use of Ionic Liquids in the Separation of Cotton Polyester Blends. RSC Adv.2014, 4(55), 29094–29098. doi: https://doi.org/ 10.1039/c4ra04306e. Asaadi, S.; Hummel, M.; Hellsten, S.; Härkäsalmi, T.; Ma, Y.; Michud, A.; Sixta, H. Renewable High-Performance Fibers from the Chemical Recycling of Cotton Waste Utilizing an Ionic Liquid. ChemSusChem.2016, 9(22), 3250–3258. doi: https://doi.org/10.1002/ cssc.201600680. Yan, N.; Chen, X. Sustainability: Don’t Waste Seafood Waste. Nature.2015, 524(7564), 155–157. doi: https://doi.org/10.1038/524155a. Younes, I.; Rinaudo, M. Chitin and Chitosan Preparation from Marine Sources. Structure, Properties and Applications. Mar. Drugs.2015, 13(3), 1133–1174. doi: https://doi.org/ 10.3390/md13031133. Vicente, F. A.; Bradić, B.; Novak, U.; Likozar, B. α-Chitin Dissolution, N-Deacetylation and Valorization in Deep Eutectic Solvents. Biopolymers.2020, 111(5). doi: https://doi.org/ 10.1002/bip.23351.

5 Alternative solvents and the UN sustainable development goals

125

[89] Sharma, M.; Mukesh, C.; Mondal, D.; Prasad, K. Dissolution of α-Chitin in Deep Eutectic Solvents. RSC Adv.2013, 3(39), 18149–18155. doi: https://doi.org/10.1039/c3ra43404d. [90] Shamshina, J. L. Chitin in Ionic Liquids: Historical Insights into the Polymer’s Dissolution and Isolation. A Review. Green Chem.2019, 21(15), 3974–3993. doi: https://doi.org/10.1039/ c9gc01830a. [91] Shamshina, J. L.; Zavgorodnya, O.; Rogers, R. D. Advances in Processing Chitin as a Promising Biomaterial from Ionic Liquids. Appl. Ion. Liq. Biotechnol.2018, 168, 177–198. [92] Samorì, C.; Cespi, D.; Blair, P.; Galletti, P.; Malferrari, D.; Passarini, F.; Vassura, I.; Tagliavini, E. Application of Switchable Hydrophilicity Solvents for Recycling Multilayer Packaging Materials. Green Chem.2017, 19(7), 1714–1720. doi: https://doi.org/10.1039/ c6gc03535c. [93] Somerville, C. Biofuels. Curr. Biol.2007, 17(4), 115–119. doi: https://doi.org/10.1016/j. cub.2007.01.010. [94] Muñoz, I.; Flury, K.; Jungbluth, N.; Rigarlsford, G.; Canals, L. M.; King, H. Life Cycle Assessment of Bio-Based Ethanol Produced from Different Agricultural Feedstocks. Int. J. Life Cycle Assess.2014, 19(1), 109–119. doi: https://doi.org/10.1007/s11367-013-0613-1. [95] Tobiszewski, M. Analytical Chemistry with Biosolvents. Anal. Bioanal. Chem.2019, 411(19), 4359–4364. doi: https://doi.org/10.1007/s00216-019-01732-2. [96] Cherubini, F.; Ulgiati, S. Crop Residues as Raw Materials for Biorefinery Systems – A LCA Case Study. Appl. Energy.2010, 87(1), 47–57. doi: https://doi.org/10.1016/j. apenergy.2009.08.024. [97] Cao, F.; Schwartz, T. J.; McClelland, D. J.; Krishna, S. H.; Dumesic, J. A.; Huber, G. W. Dehydration of Cellulose to Levoglucosenone Using Polar Aprotic Solvents. Energy Environ. Sci.2015, 8(6), 1808–1815. doi: https://doi.org/10.1039/c5ee00353a. [98] Pace, V.; Hoyos, P.; Castoldi, L.; Domínguez De María, P.; Alcántara, A. R. 2Methyltetrahydrofuran (2-MeTHF): A Biomass-Derived Solvent with Broad Application in Organic Chemistry. ChemSusChem.2012, 5(8), 1369–1379. doi: https://doi.org/10.1002/ cssc.201100780. [99] Slater, C. S.; Savelski, M. J.; Hitchcock, D.; Cavanagh, E. J. Environmental Analysis of the Life Cycle Emissions of 2-Methyl Tetrahydrofuran Solvent Manufactured from Renewable Resources. J. Environ. Sci. Heal. – Part A Toxic/Hazardous Subst. Environ. Eng.2016, 51(6), 487–494. doi: https://doi.org/10.1080/10934529.2015.1128719. [100] Paiva, A.; Craveiro, R.; Aroso, I.; Martins, M.; Reis, R. L.; Duarte, A. R. C. Natural Deep Eutectic Solvents – Solvents for the Twenty-first Century. ACS Sustain. Chem. Eng.2014, 2(5), 1063–1071. doi: https://doi.org/10.1021/sc500096j. [101] Hulsbosch, J.; De Vos, D. E.; Binnemans, K.; Ameloot, R. Biobased Ionic Liquids: Solvents for a Green Processing Industry?. ACS Sustain. Chem. Eng.2016, 4(6), 2917–2931. doi: https:// doi.org/10.1021/acssuschemeng.6b00553. [102] Stark, A. Ionic Liquids in the Biorefinery: A Critical Assessment of Their Potential. Energy Environ. Sci.2011, 4(1), 19–32. doi: https://doi.org/10.1039/c0ee00246a. [103] Shamshina, J. L.; Berton, P. Use of Ionic Liquids in Chitin Biorefinery: A Systematic Review. Front. Bioeng. Biotechnol.2020, 8(January), 1–14. doi: https://doi.org/10.3389/ fbioe.2020.00011. [104] Brandt-Talbot, A.; Gschwend, F. J. V.; Fennell, P. S.; Lammens, T. M.; Tan, B.; Weale, J.; Hallett, J. P. An Economically Viable Ionic Liquid for the Fractionation of Lignocellulosic Biomass. Green Chem.2017, 19(13), 3078–3102. doi: https://doi.org/10.1039/c7gc00705a. [105] Xia, Z.; Li, J.; Zhang, J.; Zhang, X.; Zheng, X.; Zhang, J. Processing and Valorization of Cellulose, Lignin and Lignocellulose Using Ionic Liquids. J. Bioresour. Bioprod.2020, 5(2), 79–95. doi: https://doi.org/10.1016/j.jobab.2020.04.001.

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[106] Sathitsuksanoh, N.; Holtman, K. M.; Yelle, D. J.; Morgan, T.; Stavila, V.; Pelton, J.; Blanch, H.; Simmons, B. A.; George, A. Lignin Fate and Characterization during Ionic Liquid Biomass Pretreatment for Renewable Chemicals and Fuels Production. Green Chem.2014, 16(3), 1236–1247. doi: https://doi.org/10.1039/c3gc42295j. [107] Chen, M.; Malaret, F.; Firth, A. E. J.; Verdía, P.; Abouelela, A. R.; Chen, Y.; Hallett, J. P. Design of a Combined Ionosolv-Organosolv Biomass Fractionation Process for Biofuel Production and High Value-Added Lignin Valorisation. Green Chem.2020, 22(15), 5161–5178. doi: https://doi.org/10.1039/d0gc01143f. [108] Baaqel, H.; Díaz, I.; Tulus, V.; Chachuat, B.; Guillén-Gosálbez, G.; Hallett, J. P. Role of LifeCycle Externalities in the Valuation of Protic Ionic Liquids-a Case Study in Biomass Pretreatment Solvents. Green Chem.2020, 22(10), 3132–3140. doi: https://doi.org/10.1039/ d0gc00058b. [109] Padovan, D.; Kobayashi, H.; Fukuoka, A. Facile Preparation of 3-Acetamido-5-Acetylfuran from N-Acetyl-d-Glucosamine by Using Commercially Available Aluminum Salts. ChemSusChem.2020, 13(14), 3594–3598. doi: https://doi.org/10.1002/cssc.202001068. [110] Pham, T. T.; Chen, X.; Söhnel, T.; Yan, N.; Sperry, J. Haber-Independent, Diversity-Oriented Synthesis of Nitrogen Compounds from Biorenewable Chitin. Green Chem.2020, 22(6), 1978–1984. doi: https://doi.org/10.1039/d0gc00208a. [111] Pham, T. T.; Gözaydın, G.; Söhnel, T.; Yan, N.; Sperry, J. Oxidative Ring-Expansion of a ChitinDerived Platform Enables Access to Unexplored 2-Amino Sugar Chemical Space. European J. Org. Chem.2019, 2019(6), 1355–1360. doi: https://doi.org/10.1002/ejoc.201801683. [112] Chen, X.; Liu, Y.; Kerton, F. M.; Yan, N. Conversion of Chitin and N-Acetyl-d-Glucosamine into a N-Containing Furan Derivative in Ionic Liquids. RSC Adv.2015, 5(26), 20073–20080. doi: https://doi.org/10.1039/c5ra00382b. [113] Chiappe, C.; Rodriguez Douton, M. J.; Mezzetta, A.; Pomelli, C. S.; Assanelli, G.; De Angelis, A. R. Recycle and Extraction: Cornerstones for an Efficient Conversion of Cellulose into 5Hydroxymethylfurfural in Ionic Liquids. ACS Sustain. Chem. Eng.2017, 5(6), 5529–5536. doi: https://doi.org/10.1021/acssuschemeng.7b00875. [114] Peleteiro, S.; Da Costa Lopes, A. M.; Garrote, G.; Parajó, J. C.; Bogel-Łukasik, R. Simple and Efficient Furfural Production from Xylose in Media Containing 1-Butyl-3-Methylimidazolium Hydrogen Sulfate. Ind. Eng. Chem. Res.2015, 54(33), 8368–8373. doi: https://doi.org/ 10.1021/acs.iecr.5b01771. [115] Anastas, P. T.; Warner, J. C. Green Chemistry: Theory and Practice; Oxford University Press: Oxford,1998. [116] Marathianos, A.; Liarou, E.; Hancox, E.; Grace, J. L.; Lester, D. W.; Haddleton, D. M. Dihydrolevoglucosenone (Cyrenetm) as a Bio-Renewable Solvent for Cu(0) WireMediated Reversible Deactivation Radical Polymerization (RDRP) without External Deoxygenation. Green Chem.2020, 22(17), 5833–5837. doi: https://doi.org/10.1039/ d0gc02184a. [117] Sicaire, A.-G.; Vian, M. A.; Filly, A.; Li, Y.; Bily, A.; Chemat, F. 2-Methyltetrahydrofuran: Main Properties, Production Processes, and Application in Extraction of Natural Products. In: Chemat, F.; Vian, M. A. Eds., Alternative Solvents for Natural Products Extraction; Berlin, Heidelberg: Springer Berlin Heidelberg,2014, 253–268. Doi: https://doi.org/10.1007/978-3662-43628-8_12. [118] Kerkel, F.; Markiewicz, M.; Stolte, S.; Müller, E.; Kunz, W. The Green Platform Molecule Gamma-Valerolactone – Ecotoxicity, Biodegradability, Solvent Properties, and Potential Applications. Green Chem.2021, 23(8), 2962–2976. doi: https://doi.org/10.1039/ d0gc04353b.

5 Alternative solvents and the UN sustainable development goals

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[119] Stolte, S.; Steudte, S.; Igartua, A.; Stepnowski, P. The Biodegradation of Ionic Liquids – the View from a Chemical Structure Perspective. Curr. Org. Chem.2012, 15(12), 1946–1973. doi: https://doi.org/10.2174/138527211795703603. [120] Garcia, M. T.; Gathergood, N.; Scammells, P. J. Biodegradable Ionic Liquids Part II. Effect of the Anion and Toxicology. Green Chem.2005, 7(1), 9–14. doi: https://doi.org/10.1039/ b411922c. [121] Gathergood, N.; Scammells, P. J.; Garcia, M. T. Biodegradable Ionic Liquids: Part III. The First Readily Biodegradable Ionic Liquids. Green Chem.2006, 8(2), 156–160. doi: https://doi.org/ 10.1039/b516206h. [122] Ranke, J.; Stolte, S.; Störmann, R.; Aming, J.; Jastorff, B. Design of Sustainable Chemical Products – the Example of Ionic Liquids. Chem. Rev.2007, 107(6), 2183–2206. doi: https://doi.org/10.1021/cr050942s. [123] Stasiewicz, M.; Mulkiewicz, E.; Tomczak-Wandzel, R.; Kumirska, J.; Siedlecka, E. M.; Gołebiowski, M.; Gajdus, J.; Czerwicka, M.; Stepnowski, P. Assessing Toxicity and Biodegradation of Novel, Environmentally Benign Ionic Liquids (1-alkoxymethyl-3hydroxypyridinium Chloride, Saccharinate and Acesulfamates) on Cellular and Molecular Level. Ecotoxicol. Environ. Saf.2008, 71(1), 157–165. doi: https://doi.org/10.1016/j. ecoenv.2007.08.011. [124] Wen, Q.; Chen, J. X.; Tang, Y. L.; Wang, J.; Yang, Z. Assessing the Toxicity and Biodegradability of Deep Eutectic Solvents. Chemosphere.2015, 132, 63–69. doi: https://doi.org/10.1016/j.chemosphere.2015.02.061. [125] Hou, X.-D.; Liu, Q.-P.; Smith, T. J.; Li, N.; Zong, M.-H. Evaluation of Toxicity and Biodegradability of Cholinium Amino Acids Ionic Liquids. PLoS One.2013, 8(3), e59145. [126] Demirbas, A. Use of Algae as Biofuel Sources. Energy Convers. Manag.2010, 51(12), 2738–2749. doi: https://doi.org/10.1016/j.enconman.2010.06.010. [127] Boyd, A. R.; Champagne, P.; McGinn, P. J.; MacDougall, K. M.; Melanson, J. E.; Jessop, P. G. Switchable Hydrophilicity Solvents for Lipid Extraction from Microalgae for Biofuel Production. Bioresour. Technol.2012, 118, 628–632. doi: https://doi.org/10.1016/j. biortech.2012.05.084. [128] Yang, H. Y.; Lu, W. J.; Chen, Y. C.; Chen, K. T.; Teng, J. C.; Wan, H. P. New Algal Lipid Extraction Procedure Using an Amphiphilic Amine Solvent and Ionic Liquid. Biomass Bioenergy.2017, 100, 108–115. doi: https://doi.org/10.1016/j.biombioe.2017.03.018. [129] Samorì, C.; Torri, C.; Samorì, G.; Fabbri, D.; Galletti, P.; Guerrini, F.; Pistocchi, R.; Tagliavini, E. Extraction of Hydrocarbons from Microalga Botryococcus braunii with Switchable Solvents. Bioresour. Technol.2010, 101(9), 3274–3279. https://doi.org/https:// doi.org/10.1016/j.biortech.2009.12.068 [130] Cicci, A.; Sed, G.; Jessop, P. G.; Bravi, M. Circular Extraction: An Innovative Use of Switchable Solvents for the Biomass Biorefinery. Green Chem.2018, 20(17), 3908–3911. doi: https://doi. org/10.1039/c8gc01731j. [131] Doney, S. C.; Busch, D. S.; Cooley, S. R.; Kroeker, K. J. The Impacts of Ocean Acidification on Marine Ecosystems and Reliant Human Communities. Annu. Rev. Environ. Resour.2020, 45(1), 83–112. doi: https://doi.org/10.1146/annurev-environ-012320-083019. [132] Aghaie, M.; Rezaei, N.; Zendehboudi, S. A Systematic Review on CO2 Capture with Ionic Liquids: Current Status and Future Prospects. Renew. Sustain. Energy Rev.2018, 96(March), 502–525. doi: https://doi.org/10.1016/j.rser.2018.07.004. [133] Cadena, C.; Anthony, J. L.; Shah, J. K.; Morrow, T. I.; Brennecke, J. F.; Maginn, E. J. Why Is CO2 so Soluble in Imidazolium-Based Ionic Liquids?. J. Am. Chem. Soc.2004, 126(16), 5300–5308. doi: https://doi.org/10.1021/ja039615x.

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[134] Aki, S. N. V. K.; Mellein, B. R.; Saurer, E. M.; Brennecke, J. F. High-Pressure Phase Behavior of Carbon Dioxide with Imidazolium-Based Ionic Liquids. J. Phys. Chem. B.2004, 108(52), 20355–20365. doi: https://doi.org/10.1021/jp046895+. [135] Bates, E. D.; Mayton, R. D.; Ntai, I.; Davis, J. H. CO2 Capture by a Task-Specific Ionic Liquid. J. Am. Chem. Soc.2002, 124(6), 926–927. doi: https://doi.org/10.1021/ja017593d. [136] Goodrich, B. F.; de la Fuente, J. C.; Gurkan, B. E.; Lopez, Z. K.; Price, E. A.; Huang, Y.; Brennecke, J. F. Effect of Water and Temperature on Absorption of CO2 by AmineFunctionalized Anion-Tethered Ionic Liquids. J. Phys. Chem. B.2011, 115(29), 9140–9150. doi: https://doi.org/10.1021/jp2015534. [137] Gurkan, B.; Goodrich, B. F.; Mindrup, E. M.; Ficke, L. E.; Massel, M.; Seo, S.; Senftle, T. P.; Wu, H.; Glaser, M. F.; Shah, J. K.; Maginn, E. J.; Brennecke, J. F.; Schneider, W. F. Molecular Design of High Capacity, Low Viscosity, Chemically Tunable Ionic Liquids for CO2 Capture. J. Phys. Chem. Lett.2010, 1(24), 3494–3499. doi: https://doi.org/10.1021/jz101533k. [138] Wang, C.; Luo, H.; Jiang, D.; Li, H.; Dai, S. Carbon Dioxide Capture by Superbase-Derived Protic Ionic Liquids. Angew. Chemie.2010, 122(34), 6114–6117. doi: https://doi.org/10.1002/ ange.201002641.

Mahin A. Zaman and Anne E. Marteel-Parrish

6 A sustainable development approach to promoting water security in Eritrea Abstract: Human life cannot exist without water. Yet over two billion people in the world do not have guaranteed access to clean water. The nation of Eritrea in Africa suffers from the highest water insecurity in the world. Of the total population, 80.7% of Eritreans do not have access to clean water. One approach to address water insecurity can be pursued using sustainable development, which is defined as a development that meets the needs of the present without compromising the ability of future generations to meet their own needs. The definition of sustainable development, in conjunction with the notion of development as freedom and an understanding of the effects of climate change, created a working definition for the pursual of a sustainable development approach. Three United Nations (UN) sustainable development goals (SDGs) were identified as targeted goals: goal 3: good health and well-being; goal 6: clean water and sanitation; and goal 16: peace, justice, and institutions that apply to the alleviation of water insecurity in Eritrea. While these three SDGs are pertinent to the issue, goals 1, 11, and 13 are also applicable. The identification of environmental issues, water insecurity, and institutional issues in Eritrea led to an integrated solution requiring the application of the principles of green chemistry. The usage of moringa seed powder and scallop powder method followed by bio-sand filtration and the usage of magnetic recyclable TiO2 sol–gel particles were determined to be two potential solutions that followed the principles of green chemistry and were sustainable options for Eritrea. The proposed chemistry-based solutions must be used synergistically with the SDGs for the root of the crisis to be addressed. Water security can be achieved through the combination of SDGs, governmental transparency in institutions, aid from international organizations, and the principles of green chemistry. Keywords: water security, climate change, sanitation, bio-filtration, sol-gels

6.1 Topic introduction Every living organism on the planet needs water to survive. Water is so integral to human life that we cannot go 3 days without consuming it [1]. Access to clean water is essential to the development of the human body. People in the Western World take access to water for granted so much that it has become a meme on social media “to

Mahin A. Zaman, Anne E. Marteel-Parrish, Department of Chemistry, Washington College, 300 Washington Avenue, Chestertown, MD 21620 https://doi.org/10.1515/9783110723960-006

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hydrate” your body. Water is required for the successful functioning of all internal organs, as well as for general hygienic purposes. As such, water is a human right. Although water is a human right, not everyone has access to it. Over 2 billion people globally do not have access to clean water facilities. To put that number into perspective, the population of the USA is about 330 million, which means 17% of the world’s population does not have access to clean water. Given that the global population is nearly 7.8 billion, about 26% of the world’s population does not have access to clean water. This is also an indication of a large gap in global equity, which is not only a human rights issue, but a justice, diversity, inclusion, and equity issue as well. Water security crises must be addressed on a national basis, beginning with nations that have the greatest water insecurity. The nation of Eritrea has the largest overall percentage of its population living without clean water [2]. Although this is an inherently important issue, there is very little published research regarding this fact. There are significant gaps in the literature regarding the description of this issue and solutions to this ongoing crisis. Water insecurity affects many individuals in different ways. In order to address the issue of water insecurity, it is valuable to use the United Nations (UN) sustainable development goals (SDGs) as the driving force toward a sustainable pathway for alleviating water insecurity in Eritrea. The UN SDGs were created as a measure to continue the efforts of the UN millennium development goals (MDGs) after 2015 [3]. The purpose of MDGs was to improve global conditions by reducing the gap in gender equality, eliminating poverty, improving health conditions, promoting education, and delaying climate change via eight distinct goals [3]. As those goals expired in 2015, the SDGs were created as a replacement measure. These goals intend to expand upon MDGs but in a much more expansive manner. The eight goals of MDGs were replaced by 17 SDGs with the specific purpose of permanently ending poverty, reducing inequality, and protecting the planet [4]. These SDGs are seen as critical to the development and the progress of many nations in the Global South. A description of each of the 17 SDGs is provided in Appendix 6.9.1. The root of both MDGs and SDGs is the concept of development, and in the latter case, the focus is on sustainable development specifically. The term “development” is defined in a variety of manners, but one of the goals of this chapter is to expand upon previous definitions of development to analyze the interrelation between three specific goals and their application to water insecurity in Eritrea. While the concept of development is not a new term in political discourse, sustainable development is a more recent concept, which will also be defined and expanded upon from previously established definitions in this chapter. Sustainable development is a pathway leading to the amelioration of crises that plague nations suffering from detrimental health and environmental crises. One of the nations for which the application of the concept of sustainable development may be beneficial is Eritrea. Eritrea suffers from a lack of access to clean water and

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is ranked as the leading nation in terms of national lack of access to proper sanitation [2]. The lack of access to clean water ties directly into “goal 6: clean water and sanitation,” but it also affects the health of the inhabitants of Eritrea, as well as their overall well-being. It is also indicative of the nature of the political structures and institutions that affect the general accessibility of water. As such, “goal 3: good health and well-being” and “goal 16: peace, justice, and strong institutions” apply to the promotion of clean water in Eritrea. While the main goals addressed in this chapter are “goals 3, 6, and 16,” “goal 1: no poverty,” “goal 11: sustainable cities and communities,” and “goal 13: climate action” are also relevant to the promotion of water security. Sustainable development must be viewed from a broad perspective as sustainability not only relates to environmental conditions but individuals as well. As such, the viewpoint of sustainable development in Eritrea must be viewed from an interdisciplinary lens that is incorporative of social, political, ethical, and scientific elements. This chapter thus begins with a definition of development, environmental wellness and climate change, and sustainable development. This will be followed by a discussion of the origins of the UN SDGs, which are integral to providing a sustainable development-oriented solution to water insecurity in Eritrea [4]. To gain more insight into the country of Eritrea, a brief historical background, as well as a description of environmental issues in the nation, the water insecurity crisis, and institutional failures that have led to this crisis are provided. It is important to be aware of the existing methods for water retrieval currently used in Eritrea as well as some other nations in the Global South. Sustainable methods for water purification will be presented and assessed for implementation in Eritrea. The primary goal of this chapter is to propose a strategic plan specific to Eritrea. The needs of the Eritrean people must be taken into consideration, as well as the potential drawbacks and costs of implementing solutions that are environmentally but not financially sustainable for the nation. As such, this chapter attempts to propose solutions that are both environmentally and financially sustainable to avoid the issue of prescribing a solution that neglects the needs of the people as mentioned in the next section.

6.2 Goals of the chapter The objective of this chapter is to propose an integrated solution for water inequality in Eritrea through a sustainable development lens. The general framework is as follows: an overarching definition of development and sustainable development, an analysis of the political structures and institutions in Eritrea, a description of causes for water insecurity in the nation, impacts of deforestation and climate change in the region, an analysis of existing methods for water purification and

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irrigation, an analysis of goals 3, 6, and 16 in the framework of decreasing water insecurity, and tentative solutions. This chapter attempts to provide an understanding of the history of Eritrea, in terms of its recent independence from Ethiopia as well as its demographic trends, political indicators, and institutions. Understanding the history of Eritrea is integral to the understanding of its infrastructural and political shortcomings that have led to its environmental crises, and subsequent lack of access to clean water. There is no easily accessible data regarding water insecurity in Eritrea, which begs the questions as to whether or not the SDGs are even considered in assuaging the crisis. To what extent are “goal 3: good health and well-being,” “goal 6: clean water and sanitation,” and “goal 16: peace, justice, and institutions” being used to promote efforts to reduce water insecurity in Eritrea? The hypothesis assumed here is that the SDGs are not being utilized to their fullest extent in order to alleviate the effects of water insecurity in Eritrea. This may be due to a lack of institutional shortcomings, and as such, an assessment of methods for mediating the crisis should be pursued. The research will be conducted through an examination of the existing literature on Eritrea, as well as on water-related crises that have been alleviated in the Global South. This chapter examines how the singular party system of politics as well as lack of transition from one president since 1993 in Eritrea has influenced how the past and current administration has taken efforts to improve access to water and sanitation in the nation [5]. To truly look at the root of water insecurity in Eritrea, there must be an analysis of the dictatorial politics in the nation, as well as demographic characteristics and infrastructure. What infrastructure is in place to promote access to clean water for all? This chapter also discusses Eritrea as a nation and how significantly climate change affects the access to water in the area, as well as environmental reasons for a lack of access to clean water in the area. What are the specific geographic elements that have been influenced by climate change? Are there indigenous methods for improving access to water? If there are indigenous methods that are more sustainable, the proposed solutions will focus on utilizing those previously established methods as well as other methods used in the Global South. The intention of the SDGs is to further eradicate and eliminate global issues, but are the SDGs being utilized correctly by the Eritrean government? Are Eritrean structures and institutions conducive for improving water insecurity in the nation? The purpose of this chapter is not to invalidate the government of Eritrea but to provide a solution that would allow for the population to have greater access to clean water. As such, the proposed solutions must be scientifically and developmentally cognizant of gaps in the literature and, possibly, in the understanding of the nation’s institutional structures. In order to gain more insight into this ongoing crisis in Eritrea, important terminology must be defined first.

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6.3 Introduction to development theory 6.3.1 Rationale The concept of development shapes how the world is viewed. It has thus molded how scholars have adapted and shaped paths forward in terms of defining and analyzing global relations. Development, at its core, is a supposedly nuanced topic in how it attempts to ameliorate global tensions. It is in the framework for sustainability and the UN SDGs. The notion of development, however, is rather problematic because it is often based on Eurocentric conceptions of progress with a linearly and singularly defined objective. Therefore, it is important to delineate a definition of development that does not focus on development solely as progress, but which is more inclusive of difficulties faced by countries following colonial vacancies. Similarly, it would make sense to define sustainable development accordingly as well. To analyze the efficacies and effectiveness of any of the specific SDGs, there needs to be a framework definition for comparison.

6.3.2 Definitions 6.3.2.1 Development Defining development is essential in understanding the UN SDGs. According to Cowen and Shenton, there is no solid definition as to what development entails [6]. The authors do, however, make an important distinction stating that development can be seen from the perspective of both an “objective process” and a “subjective course of action” [6]. As such, development, in and of itself, is seen as both the means and the goal. If development is seen as both the means and the end, there lies an integral flaw in the scope of all development-oriented projects. The authors also discuss the contrast of development to underdevelopment in terms of defining development to alleviate external chaos [6]. Underdevelopment is seen as synonymous with corruption according to Easterly, gifting the term a framework in which it poses a juxtaposition to development in its lack of industrial progress [7]. This concept is highly rooted in Eurocentric ways of thinking, with the notion that there is an intended goal to mimic the structure of Western nations. According to Herath, the notion of development is more rooted in the idea of modernization and economic growth [8]. This notion also considers development as more of an evolutionary process that is related to industrialization and global trade [8]. This definition posits that financial conditions are integral to development, which is also based on an Eurocentric notion of development as progress.

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Easterly sees development discourse as problematic in that it presents the idea that development is rooted in the idea of the free market [7]. This relates to Herath’s definition of development, given that it is tied to the free market. Easterly perceives development as the advancement of one ideology in which poorer countries are forced to adopt rules and regulations from multinational organizations and lose autonomy in their infrastructure and sovereign practices [7]. In terms of the national scope of development, Portes portrays development following three criteria: (1) increase in national growth, (2) redistribution of national income on an egalitarian basis, and (3) emergence of a new national self-image [9]. This definition is much more specific but differs from prior definitions in that it proposes the notion of an egalitarian distribution of national income. According to the second criterion, it is unlikely that many nations would be able to be classified as developed countries, as wealth disparities are highly present globally. This study, however, ascribes a lot of issues in poorer countries to rather rushed development. Portes notes that much of the Western world experienced development over a larger period [9]. A much more substantive definition of development, as crafted by Amartya Sen, is the notion of development as freedom [10]. With this concept, development is not defined as linear progress in terms of financial growth, but rather in relation to human rights. Sen asserts that there is a direct relationship between development and freedom, with freedom being substantiated by access to healthcare, education, political freedom, economic prosperity, and general equality [10]. Along the lines of this notion of development, the strong emphasis on freedom differentiates this definition of development in that it is not necessarily Eurocentric in advocating for human rights, but rather provide a middle-path approach that qualifies nations in their own respective abilities [10]. There is no abject focus on finances as the key to development in this case, but on finances for the support and furtherment of social policies. This definition of development is much more in conjunction with the notion of sustainable development, as the core of sustainable development is focused on the betterment of living conditions for all species, of which social policies and freedom tie into. As the main focus of the chapter is sustainable development, it is also important to consider environment wellness and climate change.

6.3.2.2 Environmental wellness and climate change The purpose of sustainable development is to promote environmental wellness along with the concept of development. The pursuit of environmental wellness is a new topic, as concerns regarding the environment and climate change have recently been put forth. Climate change is the largest threat to the planet, affecting the environment as well as previously determined climatic conditions [11]. Thompson argues that climate change is evidenced by rising global temperatures, melting

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glaciers, and loss of polar ice. These conditions are inherently natural over the course of millions of years, but current anthropogenic practices have exacerbated these natural processes [11]. As a result, there is a mass deterioration of global environments, which greatly affects the living conditions for humans. Climate change is an ongoing human-aggravated crisis. As it affects human beings, it brings into question the idea of environmental wellness [11]. Callicott defines environmental wellness in the context of environmental degradation, which ties into climate change. Environmental wellness is thus posed as a necessary condition for human health and well-being generally [12]. This definition is rather broad, as it only defines environmental wellness as a condition for human health. Callicott focuses significantly on the wellness movement, as well as the notion of the human body as a part of the ecosystem. However, he notes that humans are inherently a living part of the environment, and thus the human contribution to the environment cannot be ignored [12]. As such, climate change is defined as changes in climatic and environmental conditions that affect human well-being, with an emphasis on environmental wellbeing as a necessary criterion for human health [12]. These definitions tie into the framework for defining sustainable development.

6.3.2.3 Sustainable development Sustainable development was first defined by the Brundtland Commission in 1987 to discuss global issues such as a warming planet (later referred to as climate change), threats to the Earth’s ozone layer, and deserts consuming agricultural land [13]. The original intent of the Brundtland Commission was to focus on incorporating the environment into development discourse and to consider the environment as crucial to the existence of humanity [13]. As such, a working definition of sustainable development must be used in order to analyze global issues in relation to the environment, including water insecurity. The Brundtland Commission created a working definition of sustainable development that is: “development that meets the needs of the present without compromising the ability of future generations to meet their own needs” [13]. This definition of sustainable development is inclusive of two concepts as outlined in the Report of the World Commission on Environment and Development: “the concept of ‘needs’, in particular the essential needs of the world’s poor, to which overriding priority should be given; and the idea of limitations imposed by the state of technology and social organization on the environment’s ability to meet present and future needs” [13]. But this definition of sustainable development only partially addresses the concept of development. Sustainable development, according to Mebratu, attempts to be a large catchphrase for several issues [14]. The author claims that there is no true definition of sustainable development, but rather that it is a culmination of the numerous relationships

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between ecosystems and human interactions [14]. This definition, however, is rather vague. There is no reference to the environment, nor are there specific structures of the element of human needs that are explicitly mentioned. Mebratu later mentions that there are three versions used to define sustainable development: (1) institutional version, (2) the ideological version, and (3) the academic version [14]. The institutional version is more closely aligned with the intertwined nature of the environment and human interaction, and is thus more relevant. Another analysis of sustainable development presented by Hopwood also takes the Brundtland Commission’s definition of sustainable development into consideration. Hopwood furthers the analysis of sustainable development by integrating social justice as a major part of sustainable development [15]. Hopwood also extends this claim by connecting sustainable development to the economic aspect of development, citing that human consumption and economic growth are “unsustainable” [15]. Haughton argues that sustainable development must be combined with equity measures, and thus lays a framework for five equity principles related to sustainable development: (1) intergenerational equity, (2) intragenerational equity, (3) geographical equity, (4) procedural equity, and (5) interspecies equity [16]. Incorporating the concepts of diversity, inclusion, and equity provides a valuable lens of analysis regarding the specific UN SDGs of interest discussed in this chapter.

6.3.3 Purpose of the UN sustainable development goals The Brundtland Commission also created MDGs and SDGs with the focal point of sustainable development. The UN SDGs exist as a mechanism to further the idea of sustainable development. These 17 goals are focused on the implementation of measures to end extreme poverty, reduce inequality, and protect the planet by 2030 [4]. The specific SDGs that are the most relevant here are “goal 3: good health and well-being,” “goal 6: clean water and sanitation,” and “goal 16: peace, justice, and institutions.” “Goal 3” is dedicated to ensuring healthy lives and promoting wellbeing for all at all ages [4]. “Goal 6” is about ensuring availability and sustainable management of water and sanitation for all [4]. “Goal 16” is focused on promoting peaceful and inclusive societies for sustainable development, providing access to justice for all, and building effective, accountable, and inclusive institutions at all levels [4]. “Goals 3,” “6,” and “16” are directly tied to sustainable development, as well as environmental wellness and healthy populations. “Goals 1,” “11,” and “13” are applicable as well, but will not be covered in as much depth in this chapter. “Goal 1” is dedicated to ending poverty in all its forms everywhere [4]. “Goal 11” is about making cities and human settlements inclusive, safe, resilient, and sustainable [4]. “Goal 13” relies on taking urgent action to combat climate change and its impacts [4].

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According to Biermann et al., the SDGs provide a new route for global governance through the fulfillment of universal and national policies [17]. The authors criticize the SDGs as they have no mechanism for legally binding action. There is no authority guaranteeing the implementation of any of these SDGs aside from multinational organizations. As such, there are major challenges in the completion of any of the SDGs [17]. The authors pose criticism for the goals in the vagueness of their targets as well. The authors mention the “embedding and integration of goals at a global level” as a mechanism for positive change, but there are only a few institutions that are capable of such efforts [17]. Costanza et al. postulate that the SDGs have three intended purposes concerning the economy (high quality of life or well-being), society (equitably shared), and the environment (sustainable, staying within planetary boundaries) [18]. This aligns with the previously established definitions of development and sustainable development, as well as the notion of diversity, equity, and inclusion. The authors further claim that although the SDGs have intended targets, there are planetary concerns that need to be taken into consideration [18]. These planetary concerns will provide a platform for the analysis of the actual sustainable nature of the SDGs later in this chapter. Further research by Costanza et al. outlines a methodology to assess the SDGs that is inclusive of a framework referred to as the Sustainable Well-Being Index (SWI) [19]. The SWI outlines a framework under which Costanza agrees with the previous point of a prosperous, high quality of life that is equitably shared and sustainable. The SWI are based on (1) consumption, production, and wealth-based indicators, (2) aggregation of all of the SDG indicators into a unitless index, and (3) contributions to subjective well-being [19]. The authors graphically measure the progress of the goals and measure the interconnectedness of the goals as well. This will provide a deeper framework for the analysis as to whether or not the SDGs are being effectively utilized. Laurent et al. also discuss the SDGs in terms of a life-cycle-based analysis. The authors propose a new method for measuring sustainable well-being as well, which relates to assessing methods for sustainable development in relation to SDGs [20]. Laurent et al. elaborate that their framework for analysis is inclusive of a 5-phase method in which they focus on defining the application of the project, scoping the assessment, inventorying effects from project applications, identifying the assessment of contributions to the goals, and interpreting the results and benefits [20]. This is different from the other approaches in that it takes on a more scientific analysis. This method is also similar to the analysis by Pradhan et al. of the measurement of synergies and trade-offs with the SDGs in terms of positive and negative correlations to their targets [21]. Vasseur et al. criticize the SDGs for their poverty-focused lens, claiming that an environmental governance perspective would be better utilized for the completion of all the goals, as there would be a better understanding of the way ecosystems affect sustainable practices [22]. This perspective is focused on the completion of “goals 6, 13, 14, and 15” as the main targets [22] and is almost Eurocentric. Although

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environmental sustainability is important, it is necessary to focus on specific groups of people and their desires because nations in the Global North do not necessarily know what is better for nations in the Global South. As the concept of development is rather Eurocentric in and of itself, there is a need to detract from pushing an ideology onto groups of people.

6.3.4 Conclusion In analyzing the effectiveness and cogency of SDGs, there needs to be a working definition of sustainable development that can further the utilization of SDGs. There also needs to be a clear mechanism and path for which the SDGs are implemented. If the intended purposes of the goals are to end extreme poverty, reduce inequality, and protect the planet by 2030, there needs to be more of an internationally enforceable effort to do so. This reinforces the necessity to reframe development and sustainable development, as well as to focus on how diversity, inclusion, and equity can be incorporated through the primary SDGs. The implementation of SDGs must be done in a manner that is cognizant of the existing political structure of a specific country. In this chapter, Eritrea was chosen as the case study country. The first step is to present intangibles about this country which will allow for a more robust understanding of this choice.

6.4 The case of Eritrea Eritrea is a small nation in East Africa, bordered by the Red Sea, Ethiopia, Sudan, and Djibouti. This small nation is home to about 6.3 million people, with the largest proportion of the population residing in the capital city Asmara [5]. A general map of Africa is shown in Figure 6.1 [23]. A map of Eritrea is referenced in Figure 6.2 [5]. Eritrea is a very small country in Africa, as is referenced in Figure 6.1 [23]. The nation is so small that it is difficult to see it because of its larger border nations of Sudan and Ethiopia. Formerly the Ethiopian kingdom of Axum (alternatively Aksum), the nation was heavily involved in sea trade until 700 CE [24]. The nation’s influence in the region was minimalized to a small Christian settlement before its adoption into the Abyssinian kingdom in 1500 CE. As a part of the Ottoman Empire, there were contentious relationships with the other kingdoms of Ethiopia, as the two cultures differed significantly in terms of religion and cultural practices [24]. With the slow dismantlement of the Ottoman Empire, Eritrea was overtaken by Italian forces and subjected to Italian colonialism. As an Italian colony, the nation became increasingly less autonomous as indigenous and local peoples lost claims to their land [24]. Italy maintained a hold over Eritrea until British forces battled Italian forces for the territory in 1940, the British claiming victory in 1941. Even so,

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Figure 6.1: Map of Africa [23].

British forces were not heavily involved in Eritrean politics, and withdrew their forces in 1944, leaving a significant power vacuum [24]. As the end of World War II attempted redistribution of African lands, there was conflict regarding the fate of Eritrea’s sovereignty, and ultimately it was declared a part of Ethiopia in 1952. There were significant conflicts related to the integration of Eritrea in Ethiopia, as Eritrean citizens were not granted the same privileges as Ethiopians [24]. Eritrea fought against Ethiopian forces for independence, with the aid of the Soviet Union, and declared independence in 1993 [24].

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Figure 6.2: Map of Eritrea [5].

The newfound independence allowed for the creation of a unitary political system and singular political party in Ethiopia, with residing President Isaias Afwerki [5]. The nation is now primarily agrarian, with 80% of the workforce involved in agriculture. This makes the issue of deforestation and climate change in the nation even more prominent. As the nation is primarily agrarian, arable land and water are needed for the population to maintain its crops. The percentage of arable land and water has steadily decreased in the region due to deforestation and climate change [2]. Deforestation and climate change, as well as the lack of proper structures and preventative measures, can lead to a myriad of issues [2]. These issues are inclusive of the main topic of this chapter: water insecurity.

6.4.1 Environmental issues in Eritrea Climate change is arguably one of the greatest issues faced by the nation of Eritrea [25]. The nation produces less than 0.01% of the total global greenhouse gas emissions, but it is one of the most highly affected nations in terms of environmental

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fallout [26]. Most global greenhouse gas emissions are produced by countries in the Global North, and countries in the Global South bear the burden of pollution and increasing environmental crises. Environmental consequences of climate change have led to changing weather patterns: infrequent rain, severe droughts, and unpredictable flooding [27]. Eritrea does not have significant access to waterways; the nation relies on the Setit River and the Gash Barka system [28]. These are the only two consistent sources of water in Eritrea, as the other bodies of water in the region are reliant on rainwater. Climate change in Eritrea has directly contributed to deforestation, which has impacted the primary source of food production. Approximately 80% of the population of Eritrea lives in rural areas and depends on subsistence agriculture for their food production [27]. Deforestation has led to a decreased percentage of forest land mass from 30% of the total land mass in 1996 to 1% in 2006 [29]. Decreased forest land mass leads to soil erosion, as well as reduced soil quality due to insufficient resource regeneration. Soil erosion further pollutes waterways by depositing soil with high chemical concentrations into major water systems. The geology of the region makes the soil high in its salt concentration, as well as other natural pollutants as well [28]. The water thus carries the soil downstream, and any present chemicals are able to disperse into the water. The polluted water sources can be devastating to rural or indigent populations who have no means of water purification. The results of climate change have only further intensified water insecurity in impoverished regions, showcasing the growing wealth gap in the effects of climate change. Nations in the Global South are much more affected by climate change than nations in the Global North [30]. This makes it even more important for the completion of “goals 1, 11, and 13.” It is pertinent to address the effects of climate change on poverty levels while building sustainable cities. Water insecurity has led to a myriad of other issues in the nation as well.

6.4.2 Water insecurity A few of the most prominent issues in Eritrea are lack of sanitation, political insecurity with conflicts in relation to Ethiopia, food insecurity, public health crises, and water insecurity [25]. Eritrea ranks globally as the number one nation in the world with the highest proportion of its population without access to clean drinking water, at 80.7% [2]. In the context of a population of nearly 6.3 million people, 80.7% is a little over 5 million people. Five million people in the nation of Eritrea do not have access to clean water. Water is not only used for drinking but also bathing, washing, and cooking. Unclean drinking water can lead to severe health issues, including diarrhea and cholera, which are both prominent in Eritrea. The leading cause of death for children under 5 years old is diarrheal infection [31]. As these illnesses are related to contaminated water sources, they are highly preventable if

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access to clean water would be guaranteed. These issues are directly relevant to goals 3 and 6, as they relate to the health of the population as well as the direct lack of clean and safe water. Although multiple reports corroborate that 80.7% of the population of Eritrea is water insecure, a statement from the general director of water resources in the Ministry of Land, Water and Environment in 2013 stated that access to drinking water had improved to 85% [32]. These statistics are in direct contradiction, which presents an issue on its own. There seems to be huge discrepancies in the released data. These inconsistencies are representative of an institutional problem. The systems in place in Eritrea are not equipped to implement sustainable practices for improving water security. Although the purpose of this chapter is not to dismantle existing systems of power, there is evidence of power structures that are not conducive to sustainable practices in the nation. This directly relates to “goal 16” of SDGs.

6.4.3 Institutional issues in Eritrea Eritrea, as well as many other nations in the Global South, falls into the category of states with poor structural management. The existing governmental structure of the nation is consistent of an executive, legislative, and judicial branch. The executive branch is composed of the president, 16 cabinet members, and governors and state officials. The legislative branch is a unicameral 150-member national assembly with 75 central committee members and 75 elected representatives. The judicial branch consists of national-, regional-, and village-level courts [33]. Although there are three branches of government, the rulings in the nation are predominantly made by the president. The lack of transition of power between 1994 and 2021 is indicative of the national political stagnation in the nation. The People’s Front for Democracy and Justice is the only political party that is allowed to exist in the nation, and President Afwerki serves as both the head of the state and the head of the government [34]. Given the singularity of the political structure, there is no political gridlock to impede in the enactment of any and all political goals. This begs the question as to whether or not there are financial or infrastructural shortcomings that have impacted the water security in the nation. Eritrea is no stranger to border conflicts as well, having consistent tensions with Ethiopian forces following the independence of the region in 1993. President Afwerki has used the absence of peace between the two nations as a justification for the authoritarian rule in the nation [35]. Eritrean forces are also actively involved in the Ethiopian Tigray conflict in which civilians in the Tigray region are being massacred by the Ethiopian government. There are significant inconsistencies in the Eritrean government’s priorities regarding its citizens. The number of humanitarian abuses in the region is indicative of how misplaced priorities are. The nation is one of the most food-insecure nations in the

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African region, as well as the most water-insecure nation [27]. Climate change has only exacerbated existing infrastructural issues in the region, causing the constituents to suffer tremendously. Eritrea is a member state of the UN system and is thus a member state of all international organizations that fall under the jurisdiction of the UN [27].

6.5 The role of international organizations Although the SDGs serve as a proposal for the betterment of global conditions, there is little mechanism of enforcement. The extended UN system is responsible for carrying out the intended SDGs, but there are no legally binding contracts that can effectively promote their implementation. International organizations such as the UN Development Programme (DP) and the UN Environment Programme (EP) are tasked with the fulfillment of the SDGs, but these organizations are limited in their power. The UNDP operates in the field as the humanitarian agency that attempts to eradicate poverty and promote climate justice. The UNDP operates in nearly 170 countries, citing the SDGs as one of their primary targets for action [36]. As previously mentioned, the primary focus of this chapter relates to “goal 3: good health and well-being,” “goal 6: clean water and sanitation,” and “goal 16: peace, justice, and institutions” [4]. The UNDP has an official budget of $7.49 million dollars to spend in the region in 2021, and 70.5% of the allocated budget has been utilized toward “the eradication of poverty in all forms and dimensions” [36]. This leaves a meager $2.21 million for the actualization of the remaining targets of SDGs. As Eritrea has the greatest global water insecurity, these funds are insufficient to address the root of the problem. The UNEP is dedicated to the promotion of sustainability, following the trend of sustainable development [37]. While the UNEP is the environmental branch of the UN system, it suffers the same shortcomings that plague numerous international organizations: it can only make recommendations. The UNEP acts as a resource and a forum in the scope of their purpose [38]. They are a resource for states to tap into to access assistance in the determination of environmental policies and laws. The UNEP is also a forum for states to be able to voice their concerns regarding environmental decisions and policies [37, 38]. Member states, however, do not make significant financial contributions to the UNEP. They receive 95% of their funding from donations and utilize the environmental fund for its flexible funding for work across the globe [37]. While there are global partnerships in place with the UNEP, there is still no mechanism for the enforcement of the targeted goals of the UNEP, which indirectly includes the SDGs.

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Therein lies the problem regarding international organizations and compliance: there is no binding agreement in place that necessitates the implementation of any international ordinances or policy recommendations. There is no international government, only international organizations that employ soft power [39]. International law only exists as recommendations, even if they are seen as binding in name [39]. Eritrea, being plagued by its infrastructural and financial inequities, has little capacity for adherence to the SDGs. The UNDP, in its nature as a humanitarian field agent, is involved in the nation, but its budget is limited. The UNEP can only serve as a forum and a resource for nations, but it is not capable of direct action. For water insecurity to be alleviated in Eritrea, there must exist a more comprehensive plan that combines the SDGs and the implementation of sustainable methods targeting the root of the issue: water purification.

6.6 Current water purification methods in Eritrea and the Global South There are existing methods for water retrieval and purification in the region. One of the most prominent methods is an indigenous irrigation method [40]. As referenced in Figure 6.3, this indigenous method is used for irrigation purposes in the Wadi Laba ephemeral stream. The indigenous method uses irrigation as its main force for water direction and water retrieval. In doing such, the water was distributed fairly across the region [41]. Farmers in the region have classified the different types of flooding patterns as small, small-medium, medium, medium-large, large-good, and reka (an indigenous term for a generous gift from God). The flooding pattern determined how much land was irrigated from the discharge of water. The water was originally equally distributed from the Wadi Laba to the two irrigation canals: the Sheeb-Kethin and Sheeb-Abay [41]. This method was highly successful in its water retrieval for years, but due to climate change, it is no longer feasible. Climate change has disrupted the amount of rain in the region, which in turn affected existing irrigation cycles. As there are no longer any predictable flooding patterns, this significantly impacts the way in which local people are able to get access to clean water [41]. The disruptions have limited farmers’ ability to obtain food and fodder for livestock, which affects their health as well, indicative of an insufficient diet that could lead to malnutrition. Farmers in the region are willing to cooperate for the annual reconstruction of irrigation systems in the region, but the costs and benefits are not sustainable in the long run. Annual reconstruction does not attack the root of the problem: lack of infrastructure and developmental barriers that impede the utilization of the SDGs as well as the implementation of sustainable water purification methods.

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Figure 6.3: Indigenous irrigation layout in Wadi Laba [41].

In the Global South, other methods for water purification were tested as well, including the usage of moringa seed powder in conjunction with scallop shell powder prior to sari or sand filtration in Bangladesh. Moringa is a plant that has numerous medicinal properties, but is notable in this case for its coagulation properties [42]. Scallop shell powder has been noted that as a food additive, it decreased the bacterial count in numerous crops, making it incredibly beneficial for protecting against waterborne illnesses which have detrimental health effects [42]. In conjunction, the two are referred to as MOSP (moringa seed powder and scallop powder). Bangladesh is similar to Eritrea in that both nations struggle with water security, although both nations have coastal borders. In the case of Bangladesh, the moringa and scallop shell powder method for water purification was tried using two secondary procedures to attempt to effectively and cheaply purify water: using sand/gravel/charcoal and sari filtration. Saris are commonly used and purchased clothing items, making it a much more accessible option for local communities in Bangladesh [42].

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The difference between the two methods was present in the structural filtration of the water, as the sand filtration method utilized a much more structured device than the sari method in which the clothing was folded three times to create eight layers in-between. Figure 6.4 depicts the apparatus that was utilized for the sand filtration method, which utilizes polyvinylchloride pipe [42]. MOSP, written as NMOSP in Figure 6.4, refers to the combination of the moringa and scallop shell powder [42].

Figure 6.4: Bio-sand filtration of water in Bangladesh [42].

Both methods were tested against US Environmental Protection Agency (EPA) standards for water purification as well. In the case of the sari filtration method, nearly all pathogens were found to be removed from the water, with the exception of one rare pathogen [42]. In the bio-sand filtration method, all pathogens were removed. In turbidity testing, which refers to the haziness or cloudiness of a fluid, the moringa treatment followed by bio-sand filtration was able to reduce turbidity levels from 54.0–59.0 NTU (Nephelometric Turbidity Units) to 0.9–4.1 NTU, which is close to US EPA standards of 0.5–1.00 NTU [42]. The MOSP followed by the sari method was able to reduce levels to 20.0–25.0 NTU, which still shows a significant decrease in the turbidity levels. In all other methods for testing, both methods similarly filtered out toxic chemicals, the only difference being that the sari method resulted in a higher water pH at 9.9 in comparison to a pH of 7.6 for the MOSP treatment [42]. The MOSP treatment followed by bio-sand filtration was overall the better method, while also maintaining a relatively low cost. The MOSP followed by bio-sand filtration method is one option for sustainable and cost-effective water purification.

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In Eritrea, moringa powder, without scallop powder and bio-sand filtration, was tested using a microbiological survey (MBS) method, which measures the catalytic activity of redox enzymes in correlation to bacterial concentrations in a single-use reaction [43]. This study was done to determine the effectiveness of moringa seed powder in reducing bacterial concentrations in water sample, as much of the research regarding moringa seed water purification is centered around turbidity [43]. Moringa seed filtration was proven to be one of the most effective natural methods for the reduction of suspended particles in water, which made it a good candidate for water purification. In this study, water samples were collected in Asmara, Cheren, Akrur, and Saganèiti, and tested by adding moringa seed flour for 1 h before cotton cloth filtration [43]. The MBS study determined that, in Eritrea, moringa seed filtration was not effective in reducing the bacterial concentration present in collected water samples. The lack of bacterial removal in water samples treated with moringa seed powder was confirmed by a study done in Cameroon [44]. Water samples were collected from the Biyeme River in Cameroon, and tested for turbidity, bacterial concentrations, and organic matter removal after moringa seed filtration using physicochemical characterization. The study determined a 98% reduction in turbidity after water treatment, but that the concentration of organic matter, which may lead to the growth of bacteria, did not decrease [44]. The results of the studies done in Eritrea and Cameroon, however, differ in methodology from the results of the MOSP study. The reduction of pathogens following MOSP treatment in Bangladesh indicates that the MOSP method may be superior to only using moringa powder for bacterial reduction, and thus a viable option for water purification. Moringa powder filtration is still an option for sustainable water purification, but other sustainable methods may be utilized in Eritrea for the promotion of water security.

6.7 Sustainable water purification methods In order to effectively utilize the SDGs toward the alleviation of water insecurity in Eritrea, sustainable methods for water purification based on the core concepts of green chemistry were investigated. The concept of sustainability should be used synergistically with the principles of green chemistry for the achievement of SDGs. Green chemistry, at its core, is not a political concept; the main focus is on the delineation of synthetic pathways that reduce pollution before it is created [45]. The application of green chemistry relies on 12 main principles, which are listed in Appendix 6.9.2. The most relevant principles of green chemistry to this chapter are prevention, atom economy, and design for energy efficiency [45]. There are numerous chemical methods for water purification but these do not utilize the principles of green chemistry. A few of these commonly used methods

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include distillation, membrane filtration, photocatalytic degradation, and physical adsorption. Distillation involves the process of thermal evaporation in order to separate water molecules from other pollutants or other nondesired compounds [46]. This is demonstrated in Figure 6.5, in which a round-bottom flask is heated to evaporate out water molecules. The purified water is distilled in the Erlenmeyer flask for collection [46].

Figure 6.5: Apparatus for distillation [46].

Membrane filtration involves the process of forcing water through a filter membrane with a high surface area to remove contaminants from the water by trapping particles that are too large to pass through the membrane [47]. Figure 6.6 is an example of membrane filtration in which polluted water is forced through a feed and purified water is permeated out [48]. Photocatalytic degradation involves the utilization of solar radiations as a mechanism for initiating photocatalytic, or light-radiated, processes that disinfect organic pollutants [49]. Figure 6.7 shows an example of photocatalytic radiation using sunlight as the photoradiator. Photocatalytic degradation relies on the creation of electron–hole pairs that allow for the oxidation and reduction of electron–hole pairs to separate water molecules from pollutants. Physical adsorption is a spontaneous physical process that involves the capturing of particles in a solid porous material through the adherence of nonwater

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Figure 6.6: An example of membrane filtration [48].

Figure 6.7: Simplified diagram for photocatalytic degradation [49].

molecules to the solid porous surface [50]. These are all viable and traditional methods for water purification, but more sustainable methods are now surfacing. One contemporary sustainable methodology for water purification is the utilization of switchable dispersion of multifunctional Fe3O4–reduced graphene oxide (Fe3O4–rGO) particles. This method involves the combination of photocatalytic degradation and adsorption as well as solar-driven localized interfacial evaporation [50].

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The two modes are referred to as uniform dispersion nanofluid mode and interfacial assembled mode. The uniform dispersion nanofluid mode uses Fe3O4–rGO nanoparticles for adsorption and photocatalytic degradation, and the interfacial assembled mode uses the Fe3O4–rGO nanoparticles as a floating film at the air–water surface [50]. The two modes are depicted in Figure 6.8.

Figure 6.8: Schematic for the uniform dispersion nanofluid mode and interfacial assembled mode [50].

One of the biggest issues with photocatalytic degradation used in singularity is the low-migration ability of electron–holes. In combination with adsorption, there is an increase in the contact efficiency of the molecules, thus countering the low-migration nature. The utilization of interfacial solar-thermal localization, which requires the solar absorber to be at the air–water interface, also provides a greener method for clean water generation. This methodology is more sustainable in that the Fe3O4–rGO particles purify water with higher efficiency, with a 74.7% evaporation efficiency for the interfacial assembled mode under conditions that mimic solar radiation. With the usage of magnets, the particles can also easily be recycled as well [50]. In relation to the “goal 6: clean water and sanitation” of the SDGs, this is incredibly beneficial. Clean water generation through the utilization of Fe3O4–rGO particles would make water purification much more expedient, as well as environmentally friendly. From a green chemistry perspective, this method aligns with the notion of design for energy efficiency, and the principle of atom economy is easily accomplished with the recycling of the Fe3O4–rGO particles. Although photocatalytic degradation has its faults in that it has a low-migration ability of electron–holes, the usage of semiconductor band gap materials, such as

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TiO2, which can be easily recycled, makes photocatalytic degradation much more applicable and sustainable in the context of water insecurity in Eritrea. On its own, however, TiO2 particles are biohazards for wildlife, which would further affect the health of Eritrean citizens by decreasing the food supply [51]. The small size of the particles also pose a threat in that they are difficult to remove through membranes, making the case for larger molecules with the inclusion of TiO2 as an alternative for water purification. A newer method for usage of TiO2 particles is the encapsulation of magnetically separable micron-sized steel filings with a sol–gel TiO2 nanocomposite photocatalyst shell [51]. The metal particles are protected by a double sol–gel silica host matrix barrier layer, which is meant to prevent corrosion and reduce the electron–hole transfer between the TiO2 and steel filings [51]. The results of a study done by Wilson et al. showed that the first-order rate constant was determined to be 1.55 ± 0.25 × 10−2/min m2 leading to 92 ± 5% dye degradation after an hour of UV radiation [51]. The coating of the molecule in a double-sol–gel silica host matrix was also effective for decreasing corrosion, as well as the electron–hole transfer [51]. In production, the sol–gel-coated TiO2 were found to be cheap, recyclable, and easy to manufacture on a smaller scale. From a green chemistry perspective, the process follows the notion of design for energy efficiency, as the first-order rate constant exemplifies. As the particles were strengthened to be corrosion resistant, as well as magnetic for easy removal, they were also created to avoid biohazardous effects, which makes this method relatively sustainable for water purification. Another method for clean water generation is the utilization of plant-based coagulants for water purification instead of chemical coagulants. Water clarification is a step in the wastewater purification process in which solids are removed from water. The most commonly used chemical coagulant for water clarification is alum, which contains residual aluminum [52]. The residual aluminum in water clarification processes has led to numerous health detriments including Alzheimer’s disease, making the usage of chemical coagulants contra to the SDGs. The sludge produced as a result of water clarification can accumulate in the form of solid waste, which is thus even more damaging to populations that cannot afford to purchase the proper chemicals for removal [52]. Fruit waste and other plants, including the previously mentioned MOSP, have been tested for their effects on water clarification. Although minimal testing has been conducted regarding plant-based coagulants in comparison to other chemical methods for water purification, it is important to note these methods as potential future advancements. For example, date seed and Jatropha curcas were noted to have high decreases in water turbidity from initial conditions, 94% and 99%, respectively, holding promising results for further testing [52]. There are, however, concerns with the usage of plant-based coagulants as many may have leaching effects into local bodies of water. The MOSP method is thus one of the most researched plant-based coagulants that has not shown leaching effects to date. The combination of the MOSP and bio-sand filtration method would also follow the principles of green chemistry. It is proven to be effective for the filtration of water,

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and much cheaper than the traditional chemical methods as moringa and scallop powder are more readily accessible to local populations. In relation to the principles of green chemistry, there is design for energy efficiency as the water purification method does not require specific temperatures, nor does it pose a significant environmental risk during the purification step. The bio-sand and saris can be used repeatedly but the MOSP may not be used in the long term and may need to be repeated. This method does, however, maximize prevention as it can be utilized for purifying and cleaning wastewater, which prevents the creation of future waste. There are numerous methods for sustainable water purification that may be utilized for promoting water security in Eritrea, but the solution to the issue must also incorporate the primary SDGs.

6.8 Conclusions There are very few institutional mechanisms for change in the context of sustainable development that would serve to alleviate water insecurity in Eritrea. The government has misreported that the percentage of people with access to clean water is at 85%, which is a gross juxtaposition to the actual percentage of people with access to clean water: 19.3% [32]. It is also important to mention that Eritrea is in a state of national debt. Their gross public debt reached 189.2% of their gross domestic product in 2019, which does not bode well for the nation in terms of the promotion of infrastructure that serves to alleviate water insecurity [53]. This begs the question as to how the SDGs might be utilized for effectively delineating a solution for the promotion of clean water in Eritrea. The three SDGs of interest in this chapter, “goal 3: good health and well-being,” “goal 6: clean water and sanitation,” and “goal 16: peace, justice, and strong institutions” provide a starting point for the implementation of a solution. “Goal 16” must be targeted first in order to provide a sustainable solution for clean water in Eritrea. The purpose of this chapter is not to provide a Eurocentric solution, but rather to focus more so on the notion of a sustainable development-oriented solution. Development should not be oriented around the notion of linear economic progress, but rather on the notion of the expansion of freedom, as stated by Amartya Sen [10]. In utilizing the concept of development as freedom, the first concept is based on establishing grounds for governmental transparency. In order to address the infrastructural shortcomings, there must be clarity in releasing information regarding water insecurity in the nation. Water insecurity at a percentage of 80.7% does not represent peace, justice, nor strong institutions. As there are also active engagements in the Tigray Massacre, there is a significant lack of peace in the region as well. The government of Eritrea must be forthcoming and honest in its dealings in order for true change to be realized. It is also important that the role of international organizations be highlighted in this case.

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International organizations, such as the UNDP and UNEP, could be much more helpful in the grand scheme of eradicating water inequality in the nation, but they have meager resources. The international system, however, has no authority for enforcement. The UNDP and UNEP are reliant on funding from other nations in the UN system, which can make funding scarce during periods of global tension or following elections in which parties run on platforms that favor political realism. With more funding, the implementation of SDGs would be much more feasible. Sustainable development cannot occur without proper institutions in place. Short-term planning will not fix the political structures in the nation that have created a disconnect between the government and its constituents. This ties into addressing “goal 6: clean water and sanitation.” In order for constituents to be able to have access to clean water, there needs to be a combination of sustainable water purification methods and transparency in communication from institutions. The irrigation method in the Wadi Laba was successful until climate change disrupted flooding patterns. Annual reconstruction of canals and dams is not a sustainable long-term solution. It is pertinent that numerous methods for green water purification be looked into, but with the understanding that whatever method is implemented must be cost-effective. Of the listed chemical methods for water purification, two seem to be the most beneficial for implementation in Eritrea: magnetic recyclable sol–gel TiO2 particles and the usage of MOSP followed by bio-sand filtration. The magnetic recyclable sol–gel TiO2 particles followed the principles of green chemistry in prevention, atom economy, and design for energy efficiency, and thus would be a useful method for water purification in Eritrea. The method, however, may not be as cost-effective as MOSP followed by bio-sand filtration. As there are limited funds from international organizations, the combination of both methods may serve as a more cost-effective solution. The TiO2 particles method may be applied in a more urban setting, and the MOSP method may be applied in a more rural setting. This would also lead to fewer disruptions in ways of living, which is an important consideration for sustainable development. Water purification is necessary for the availability of clean water in Eritrea, but the methods must also be feasible and adapted to national needs. Without access to clean water, the quality of health is severely impaired. This ties in “goal 3: good health and well-being.” In order for good health to be achieved, institutions in the nation need to make clean water a priority. The leading cause of death for children under 5 years old is diarrheal infections, which could be largely prevented with access to clean water. It is pertinent that the government of Eritrea utilize sustainable development, as defined by the Brundtland Commission to be “development that meets the needs of the present without compromising the ability of future generations to meet their own needs,” while addressing climate change and development as well. Eritrea is not at fault for the devastating effects of climate change that have disrupted the natural patterns of weather in the nation, yet they suffer tremendously. Global efforts, in conjunction

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with the UNEP, must be taken into account to mitigate the effects of climate change. This means that strong institutions must actively work together to improve governmental transparency, as well as focusing on infrastructure. Policies must be focused on the idea of development as freedom in order for the citizens of Eritrea to have access to clean and safe water.

6.9 Appendix 6.9.1 The United Nations sustainable development goals Goal 1: no poverty Goal 2: zero hunger Goal 3: good health and well-being Goal 4: quality education Goal 5: gender equality Goal 6: clean water and sanitation Goal 7: affordable and clean energy Goal 8: decent work and economic growth Goal 9: industry, innovation, and infrastructure Goal 10: reduced inequalities Goal 11: sustainable cities and communities Goal 12: responsible consumption and production Goal 13: climate action Goal 14: life below water Goal 15: life on land Goal 16: peace, justice, and strong institutions Goal 17: partnerships for the goals [41]

6.9.2 Twelve principles of green chemistry 1: 2: 3:

4:

Prevention: It is better to prevent waste than to treat or clean up waste after it has been created. Atom economy: Synthetic methods should be designed to maximize incorporation of all materials used in the process into the final product. Less hazardous chemical syntheses: Wherever practical, synthetic methods should be designed to use and generate substances that possess little to no toxicity to human health and the environment. Designing safer chemicals: Chemical products should be designed to achieve their desired function while minimizing their toxicity.

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6:

7: 8:

9: 10:

11:

12:

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Safer solvents and auxiliaries: The use of auxiliary substances (e.g., solvents and separation agents) should be made unnecessary wherever possible and innocuous when used. Design for energy efficiency: Energy requirements of chemical processes should be recognized for their environmental and economic impacts and should be minimized. Use of renewable feedstocks: A raw material or feedstock should be renewable rather than depleting whenever technically and economically practical. Reduce derivatives: Unnecessary derivatization (use of blocking groups, protection/deprotection, temporary modification of physical/chemical processes) should be minimized or avoided if possible, because such steps require additional reagents and can generate waste. Catalysis: Catalytic reagents (as selective as possible) are superior to stoichiometric reagents. Design for degradation: Chemical products should be designed so that at the end of their function, they break down into innocuous degradation products and do not persist in the environment. Real-time analysis for pollution prevention: Analytical methodologies need to be further developed to allow for real-time, in-process monitoring and control prior to the formation of hazardous substances. Inherently safer chemistry for accident prevention: Substances and the form of a substance used in a chemical process should be chosen to minimize the potential for chemical accidents, including releases, explosions, and fires. [45]

References [1] [2] [3] [4] [5] [6] [7] [8]

[9]

How long can you live without water? Facts and effects https://www.medicalnewstoday.com/ articles/325174 (accessed Feb 18, 2021). 10 Worst Countries for Access to Clean Water. World Vision, 2020. Sachs, J. D. From Millennium Development Goals to Sustainable Development Goals. The Lancet. 2012, 379(9832), 2206–2211. doi: https://doi.org/10.1016/S0140-6736(12)60685-0. Sustainable Development Goals. https://unfoundation.org/what-we-do/issues/sustainabledevelopment-goals/ (accessed Sep 28, 2020). Eritrea | Facts, History & News https://www.infoplease.com/world/countries/eritrea (accessed Oct 2, 2020). Cowen, M.; Shenton, R. The Invention of Development. In: Doctrines of Development; 1996, 27–43. Easterly, W. The Ideology of Development. Foreign Policy. October 13, 2009. Herath, D. Development Discourse of the Globalists and Dependency Theorists: Do the Globalisation Theorists Rephrase and Reword the Central Concepts of the Dependency School?. Third World Q. 2008, 29(4), 819–834. Portes, A. Modernity and Development: A Critique. Stud. Comp. Dev. 1973, 8, 247–279.

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[10] Sen, A. Development as Freedom; Oxford University Press: New York, 1999. [11] Thompson, L. G. Climate Change: The Evidence and Our Options. Behav. Anal. 2010, 33(2), 153–170. [12] Callicott, J. B. Project MUSE – Environmental Wellness. John Hopkins Univ. Press. 1996, 15(1), 146–160. [13] United Nations. Report of the World Commission on Environment and Development Our Common Future. 1987, 247. [14] Mebratu, D. Sustainability and Sustainable Development: Historical and Conceptual Review. Environ. Impact Assess. Rev. 1998, 18(6), 493–520. doi: https://doi.org/10.1016/S0195-9255 (98)00019-5. [15] Hopwood, B.; Mellor, M.; O’Brien, G. Sustainable Development: Mapping Different Approaches. Sustain. Dev. 2005, 13(1), 38–52. doi: https://doi.org/10.1002/sd.244. [16] Haughton, G. Environmental Justice and the Sustainable City. J. Plan. Educ. Res. 1999, 18(3), 233–243. doi: https://doi.org/10.1177/0739456X9901800305. 17] Biermann, F.; Norichika, K.; Kim, R. E. Global governance by goal-setting: the novel approach of the UN Sustainable Development Goals | Elsevier Enhanced Reader https://reader.elsevier. com/reader/sd/pii/S1877343517300209?token=A9E96608F6D78685908B21490DE8 B843EDDBC4E28F2EA02EF7771A57E2415F6AB850B683663BD476557DEA480ADA9DA5 (accessed Sep 15, 2020). https://doi.org/10.1016/j.cosust.2017.01.010. [18] Costanza, R.; McGlade, J.; Lovins, H.; Kubiszewski, I. An Overarching Goal for the UN Sustainable Development Goals. Solutions. 2014, 5(4), 4. [19] Costanza, R.; Daly, L.; Fioramonti, L.; Giovannini, E.; Kubiszewski, I.; Mortensen, L. F.; Pickett, K. E.; Ragnarsdottir, K. V.; De Vogli, R.; Wilkinson, R. Modelling and Measuring Sustainable Wellbeing in Connection with the UN Sustainable Development Goals. Ecol. Econ. 2016, 130, 350–355. doi: https://doi.org/10.1016/j.ecolecon.2016.07.009. [20] Laurent, A.; Owsianiak, M.; Dong, Y.; Kravchenko, M.; Molin, C.; Hauschild, M. Z. Assessing the Sustainability Implications of Research Projects against the 17 UN Sustainable Development Goals. Procedia CIRP. 2020, 90, 148–153. doi: https://doi.org/10.1016/j. procir.2020.01.077. [21] Pradhan, P.; Costa, L.; Rybski, D.; Lucht, W.; Kropp, J. P. A Systematic Study of Sustainable Development Goal (SDG) Interactions. Earths Future. 2017, 5(11), 1169–1179. doi: https://doi. org/10.1002/2017EF000632. [22] Vasseur, L.; Horning, D.; Thornbush, M.; Cohen-Shacham, E.; Andrade, A.; Barrow, E.; Edwards, S. R.; Wit, P.; Jones, M. Complex Problems and Unchallenged Solutions: Bringing Ecosystem Governance to the Forefront of the UN Sustainable Development Goals. Ambio. 2017, 46(7), 731–742. doi: https://doi.org/10.1007/s13280-017-0918-6. [23] nationsonline.org, klaus kästle-; nationsonline.org, klaus kästle-. Map of Africa https://www. nationsonline.org/oneworld/map/africa-political-map.htm (accessed Nov 2, 2020). [24] Eritrea – History http://www.eritrea.be/old/eritrea-history.htm (accessed Nov 2, 2020). [25] Eritrea’s Lack of Clean Water https://borgenproject.org/eritreas-lack-of-clean-water/ (accessed Oct 16, 2020). [26] Climate Change and Its Adverse Effects. Eritrea Ministry Of Information. [27] Eritrea | UNDP Climate Change Adaptation /explore/eastern-africa/eritrea (accessed Nov 6, 2020). [28] Water | Free Full-Text | Integrating Geographical Information Systems, Fuzzy Logic and Analytical Hierarchy Process in Modelling Optimum Sites for Locating Water Reservoirs. A Case Study of the Debub District in Eritrea | HTML https://www.mdpi.com/2073-4441/3/1/ 254/htm (accessed Mar 25, 2021).

6 A sustainable development approach to promoting water security in Eritrea

157

[29] Boerma, P. Assessing Forest Cover Change in Eritrea – A Historical Perspective. Mt. Res. Dev. 2006, 26(1), 41–47. doi: https://doi.org/10.1659/0276-4741(2006)026[0041:AFCCIE]2.0. CO;2. [30] Diffenbaugh, N. S.; Burke, M. Global Warming Has Increased Global Economic Inequality. Proc. Natl. Acad. Sci. 2019, 116(20), 9808–9813. doi: https://doi.org/10.1073/ pnas.1816020116. [31] UNICEF Eritrea – Water, Sanitation and Hygiene – Overview: Water, Sanitation and Hygiene https://www.unicef.org/eritrea/wes.html (accessed Oct 16, 2020). [32] Admin. Eritrea: Access to Clean Drinking Water Improves to 85%. Madote. [33] Eritrea – Political structure http://www.eritrea.be/old/eritrea-government.htm (accessed Mar 24, 2021). [34] Eritrea: Government https://globaledge.msu.edu/countries/eritrea/government (accessed Mar 25, 2021). [35] World Report 2020: Rights Trends in Eritrea https://www.hrw.org/world-report/2020/coun try-chapters/eritrea (accessed Mar 24, 2021). [36] Nations, U. UNDP https://www.un.org/en/ccoi/undp-united-nations-developmentprogramme (accessed Mar 24, 2021). [37] Environment, U. N. UNEP – UN Environment Programme http://www.unep.org/node (accessed Mar 15, 2021). [38] Hurd, I. International Organizations Politics, Law, Practice, Second; Cambridge University Press, 2014. [39] White, N. D. Lawmaking. In: The Oxford Handbook of International Organizations; Oxford University Press, Inc, 2016, 559–580. [40] Herweg, K.; Ludi, E. The Performance of Selected Soil and Water Conservation Measures – Case Studies from Ethiopia and Eritrea. Catena. 1999, 36(1–2), 99–114. doi: https://doi.org/ 10.1016/S0341-8162(99)00004-1. [41] Mehari, A.; Schultz, B.; Depeweg, H. Where Indigenous Water Management Practices Overcome Failures of Structures: The Wadi Laba Spate Irrigation System in Eritrea. Irrig. Drain. 2005, 54(1), 1–14. doi: https://doi.org/10.1002/ird.151. [42] Zaman, S.; Begum, A.; Rabbani, K. S.; Bari, L. Low Cost and Sustainable Surface Water Purification Methods Using Moringa Seeds and Scallop Powder Followed by Bio-Sand Filtration. Water Supply. 2016, 17(1), 125–137. doi: https://doi.org/10.2166/ws.2016.111. [43] Losito, F.; Arienzo, A.; Somma, D.; Murgia, L.; Stalio, O.; Zuppi, P.; Rossi, E.; Antonini, G. Field Application of the Micro-Biological Survey Method for the Assessment of the Microbiological Safety of Different Water Sources in Horn of Africa and the Evaluation of the Effectiveness of Moringa oleifera in Drinking Water Purification. J. Public Health Afr. 2017, 8(1). doi: https://doi.org/10.4081/jphia.2017.679. [44] Talla, A.; Kenmogne, R. Physicochemical Characterization of Moringa oleifera Seeds and Possibility of Using Oil Extraction Cakes in the Treatment of Drinking Water; 2020, 2455–4863. [45] Anastas, P.; Warner, J. Green Chemistry: Theory and Practice; Oxford University Press, 1998. [46] Elliott, M.; Armstrong, A.; Bartram, J. Technologies for Climate Change Adaptation – The Water Sector; 2011. [47] Membrane Filtration for Water and Wastewater https://www.wwdmag.com/desalination/ membrane-filtration-water-and-wastewater (accessed Nov 11, 2020). [48] Cross Flow TMF Technology for Industrial Wastewater Treatment http://www.porexfiltration. com/learning-center/technology/tmf-industrial-wasterwater/ (accessed Nov 11, 2020). [49] The Future of Water Treatment: Advanced Oxidation Process https://iwa-network.org/thefuture-of-water-treatment-advanced-oxidation-process/ (accessed Nov 11, 2020).

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[50] Zhao, R.; Xu, J.; Tao, P.; Shi, F.; Yu, F.; Zeng, X.; Song, C.; Wu, J.; Shang, W.; Deng, T. Clean Water Generation with Switchable Dispersion of Multifunctional Fe3O4-Reduced Graphene Oxide Particles. Prog. Nat. Sci. Mater. Int. 2018, 28(4), 422–429. doi: https://doi.org/ 10.1016/j.pnsc.2018.05.005. [51] Wilson, M.; Cheng, C. Y. C.; Oswald, G.; Srivastava, R.; Beaumont, S. K.; Badyal, J. P. S. Magnetic Recyclable Microcomposite Silica-Steel Core with TiO2 Nanocomposite Shell Photocatalysts for Sustainable Water Purification. Colloids Surf. Physicochem. Eng. Asp. 2017, 523, 27–37. doi: https://doi.org/10.1016/j.colsurfa.2017.03.034. [52] Choy, S. Y.; Prasad, K. M. N.; Wu, T. Y.; Raghunandan, M. E.; Ramanan, R. N. Utilization of Plant-Based Natural Coagulants as Future Alternatives Towards Sustainable Water Clarification. J. Environ. Sci. 2014, 26(11), 2178–2189. doi: https://doi.org/10.1016/j. jes.2014.09.024. [53] Bank, A. D. Eritrea Economic Outlook https://www.afdb.org/en/countries/east-africa/eri trea/eritrea-economic-outlook (accessed Apr 4, 2021).

Iris S. Teixeira, Thais R. Souza, Humberto M. S. Milagre and Cintia D. F. Milagre

7 The role of biocatalysis in green and sustainable chemistry Abstract: Biocatalysis is well recognized as a greener tool for organic synthesis with many successful ongoing industrial processes. Additionally, besides the research component, it can be used in outreach activities and the Chemistry and Chemical Engineering curriculum to introduce and discuss green and sustainable chemistry. An overview of the Brazilian chemical sector’s contribution to the UN sustainable goals is also provided. Keywords: biocatalysis, sustainable chemistry

7.1 Integrating chemistry into UN sustainable development goals (SDGs) The longevity and quality of life that we enjoy today are directly related to the development of chemistry. Among the main products that benefit society are agrochemicals, pharmaceuticals, plastics, and electronics, to name a few. Over the years, the demand for chemical products has increased. Unfortunately, we saw chemistry in the twentieth century as one of the main generators of environmental and occupational problems and accidents [1]. To try to mitigate or work around these and other issues, a global challenge was proposed that consists of balancing environmental and social responsibility with economic aspects, defined as sustainable development [2]. This challenge proposed by the United Nations (UN) in 2015 established a set of 17 objectives for sustainable development that should be achieved by 2030. It is a sort of “mankind’s to-do list” that prioritizes eradicating poverty, protecting the planet,

Acknowledgments: The authors express their thanks to the São Paulo State Research Support Foundation (FAPESP), GlaxoSmithKline, and the National Council for Scientific and Technological Development (CNPq) for financing the CERSusChem network projects (Proc. 2014/50249-8), INCTBioNat (Proc. 465637/2014-0), and FAPESP regular grants (Proc. 2019/15230-8). Iris S. Teixeira thanks the Coordination for the Improvement of Higher Education Personnel – Brazil (CAPES) – (Financing Code 001) and Thais R. Rodrigues thanks the National Council for Scientific and Technological Development (CNPq) for their scholarships. We also thank CAPES for maintaining the Portal de Periódicos CAPES. Iris S. Teixeira, Thais R. Souza, Humberto M. S. Milagre, Cintia D. F. Milagre, Institute of Chemistry, São Paulo State University (UNESP), Araraquara – SP, Brazil https://doi.org/10.1515/9783110723960-007

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maintaining world peace, guaranteeing social prosperity, and establishing partnerships – 5 Ps (people, planet, prosperity, peace, and partnership). The increase in agricultural production, the drinking water supply, and the prevention or treatment of diseases are fundamental activities for society, made possible by chemistry; therefore, this area of knowledge assumes a pivotal place since it can promote articulations with the sustainable development goals (SDGs) in educational environments, research development centers, and industry [3]. In the action plan for tackling global problems, 169 goals were stipulated. We are in the “Decade of Action” (2020–2030), a period in which partnerships are expected to occur through global and local articulations, enabling the engagement of people and societies in the fulfillment of the 2030 Agenda. Accompanying this movement, actions have taken place within Brazil in teaching and research institutions and the industrial sector, with the objective of engaging educators, researchers, students, public managers, and civil society, despite the political moment experienced by the country. Initiatives such as the “Guia Agenda 2030 – Integrando ODS, Educação e Sociendade” (Agenda 2030 Guide – Integrating SDGs, Education and Society), published by Sao Paulo State University (UNESP) and University of Brasilia, are guidelines for teachers and educators in their outreach activities and exemplify how outreach projects in Brazilian universities are cooperating for the fulfillment and dissemination of each of the SDGs; examples include AquaVant – developing water monitoring by drones, Impacto Ambiental – a digital newspaper that seeks to disseminate sustainable culture, GeraSol – disclosure of solar energy in schools through playful activities for children and adolescents, and Reciclaóleo – conducting the collection of cooking oil for the production of biodiesel used on a university campus [4]. The chemical industry is considered “the industry of industries” because it is at the base of the chain of more than 96% of all manufactured goods – including textiles, electronics, automobiles, paints, and solvents – playing a fundamental role in sustainable development all around the world. The Brazilian chemical industry also participates effectively in this effort. The Brazilian Chemical Industry Association (Abiquim – Associação Brasileira da Industria Química) stands out with the Atuação Responsável and Olho vivo na estrada programs. The Atuação Responsável program, created in 1992, is a PDCA (plan, do, check, act) management tool constituting a process committed to the continuous improvement of its performance in health, safety, and the environment in which the participation of members is mandatory; the Olho vivo na Estrada program emerged to prevent unsafe attitudes in the transport of dangerous products by raising drivers’ awareness, thus eliminating accidents with chemicals in road transport [5]. Table 7.1 presents some contributions from the Brazilian chemical sector to fulfilling the 17 sustainable development objectives.

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Table 7.1: Contributions of the Brazilian chemical sector to the fulfillment of the 17 sustainable development objectives. Goal

Contributions from the Brazilian chemical sector

. No poverty

Programa Atuação Responsável® – Implementation of social projects and promotion of communication campaigns on topics such as the local operation of the industry and its effects on the community where it is based*; job and income generation

. Zero hunger

Supply of products for agribusiness such as fertilizers, safe biostimulants, equipment, and products necessary for conserving seeds and plants and allowing the preservation of genetic resources.

. Good health and well-being

From production to the innovation of raw materials for industry. Safety, Health, Environment, and Quality Assessment System: commitment to the safe handling and transportation of chemicals, prioritizing the reduction of road accidents. Olho Vivo na Estrada helps mitigate risks in the transport of dangerous products by raising drivers’ awareness.

. Quality education

Partnerships, sponsorships, donations and scholarships in training, undergraduate and graduate courses, as well as specialized training for employees, customers, external audiences, and the community. Regular promotion of environmental education courses for employees, schools, and neighborhood associations. In the community: through the Community Consultative Councils (CCCs), the chemical industry promotes projects and courses in schools, neighborhood associations, and socialization centers in the communities close to the factories on the correct disposal of waste, environmental awareness, correct and safe use of chemicals, and evasion in emergency situations, among other topics.

. Gender equality

Encouraging the implementation of programs by associated companies on the topic of gender equality and nondiscrimination. The chemical sector also contributes to women’s health, and companies are committed to fighting sexual exploitation, which still affects , children and adolescents in Brazil. The Na Mão Certa program, of which Abiquim is a supporter, represents a public commitment to protect children and adolescents against sexual exploitation on the roads.

. Clean water and sanitation

Implementation of treatment technologies that allow water reuse. Abiquim annually monitors the indicators of the companies regarding the volume of water captured and other data that reflect the progress of the companies in the better management of natural resources in their processes according to the guidelines of the Programa Atuação Responsável®

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Table 7.1 (continued) Goal

Contributions from the Brazilian chemical sector

. Affordable and clean energy

Implementation of solutions that contribute to the lowest energy expenditure along the production chain. Due to the energy matrix being primarily based on renewable sources, Brazil is generally in a privileged position in SDG. . The chemical sector plays an essential role in this scenario through technological innovations for generating and storing energy.

. Decent work and economic growth

Establishing strict guidelines for continuous improvement of worker health management. Parliamentary Front of Chemistry Abiquim works through honest and transparent dialogue between the public and private sectors to build effective public policies that promote greater industry competitiveness and sustainable economic growth with the generation of jobs and income for the population, generating  million direct and indirect jobs in all countries.

. Industry, innovation and infrastructure

The commitment to adopting new products with a focus on sustainability. The Brazilian chemical industry has the third largest share in industrial GDP and is an essential generator of skilled jobs. Abiquim prepared studies that defend the optimization of the Brazilian logistics infrastructure by replacing more polluting and less efficient modes with more competitive and sustainable alternatives, such as cabotage, rail, and pipeline transport. It is estimated that the implementation of Abiquim’s proposals would result in a mitigation of . million tons of CO per year emitted into the atmosphere by the Brazilian logistics matrix.

. Reduced inequalities

Promotion of diversity in the workforce. Abiquim has active participation in relevant regional and international forums, strengthening institutions, building efficient regulatory environments and participatory decision-making processes, thus ensuring the presence and active voice of the Brazilian chemical industry in these environments to reduce inequalities between countries.

. Sustainable cities and communities

Reduction of waste produced by companies and by the surrounding communities.

. Responsible consumption and reduction

Plastic resin producers are committed to expanding the circular economy with plastic packaging. Plastic resin producers, members of the Brazilian Chemical Industry Association (Abiquim), launched a voluntary commitment to promote and expand the circular economy’s reach in plastic packaging with the following aspirational goal: % of plastic packaging will be reused, recycled, or recovered by , reaching % by .

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Table 7.1 (continued) Goal

Contributions from the Brazilian chemical sector

. Climate action

Innovations that prioritize the use of renewable raw materials. The Brazilian chemical industry is the first industrial sector in the country to publish a position in carbon pricing, supporting public policies aimed at a low carbon economy in compliance with the international commitments assumed by Brazil.

. Life below water

Periodic monitoring of indexes to verify the reduction of waste discharged into effluents. To demonstrate their commitment to directly contribute to the issue of garbage in the seas as a complement to the Programa Atuação Responsável®, they also establish that % of the companies producing plastic resins associated with Abiquim must adopt, by , the best practices of the “Manual Perda Zero de Pellets” do Fórum Setorial dos Plásticos – Por um Mar Limpo.

. Life and land

Guarantee the acquisition of raw materials and inputs for sustainable operations. Companies in the chemical sector are responsible for creating policies and procedures to ensure that the purchase of raw materials and inputs needed for their operations is of transparent and sustainable origin, thus combating trade in goods originating from illegal deforestation and extraction and irregular exploitation of biodiversity.

. Peace, justice, and strong institutions

Participation in global governance associations. Abiquim and several of its associates are signatories of the Global Compact Brazil Network, committing themselves to the  principles of the Compact.

. Partnerships for the goals

Active participation in national or international forums; partnership with the UN Global Compact; partnerships with public institutions.

Taking advantage of the potential of Brazilian biodiversity for the sustainable development of the national industry, topics such as biorefineries, alcohol chemistry, sugar chemistry, thermochemical and biochemical routes, oleochemistry, phytochemistry, renewable energies, CO2 conversion, bioproducts, bioprocesses, and biofuels are within the scope of research of several Brazilian groups, stimulated by areas such as biology, chemistry, and engineering [6].

7.2 Green and sustainable chemistry – for how long will we need those adjectives? Unfortunately, the term “chemistry” is considered in the collective consciousness to be something terrible and harmful, which we must avoid, despite chemistry being in

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everything and bringing enormous benefits. As the basis of the most diverse productive chains in the economy, products and technologies in the chemical sector promote sustainable solutions present in numerous applications in people’s daily lives. One of the milestones of the awakening of environmental awareness was the publication of Rachel Carson’s 1962 book Silent Spring. A decade passed until the Stockholm Conference in 1972, the UN’s first event to discuss environmental preservation, and in 1987, the term “sustainable development” was introduced with the publication of the Brundtland report, Our Common Future, by the World Commission on Environment and Development. Since then, several events and initiatives have taken place. The United States Pollution Prevention Act of 1990 focused attention on the need to reduce environmental pollution. The act recognized that preventing waste at the source eliminates the cost of treating waste and strengthens economic competitiveness through more efficient use of raw materials; it led to the creation of the term “green chemistry” by the US Environmental Protection Agency, which was globally recognized with the publication of the book Green Chemistry: Theory and Practice by Anastas and Warner in 1998, which stated the 12 principles of green chemistry [7]. The city of Rio de Janeiro in Brazil was the scene of two major milestones: in 1992, it hosted the Rio-92 Conference, in which Agenda 21 was prepared and culminated in the creation of the Ministry of the Environment in Brazil in November of this same year [8]. Twenty years later, in 2012, it hosted the Rio + 20 conference for sustainable development, a forum in which the 2030 Agenda was established. By combining the processes of the Millennium Goals and the processes resulting from Rio + 20, the Agenda 2030, and the SDGs inaugurate a new phase for the development of countries, which seeks to integrate all the components of sustainable development fully and to engage all countries in the construction of the future that we want [9]. On the eve of completing a decade since the emergence of the 2030 Agenda, several reflections are necessary: how far are we going? What are the greatest challenges and obstacles? What unimagined opportunities appeared at the beginning of this journey? The term “sustainability” is quite broad and can be used in different areas such as economics, agriculture, education, business, chemistry, and engineering. Sustainable chemistry comprises a new range of open areas, such as chemical product policies, technologies for remediation, exposure control, water purification, alternative energies, and green chemistry. As pointed out by Graedel, a sustainable technology must be economically viable in addition to using natural resources at rates that do not unacceptably deplete supplies in the long run, and the rates of generated waste must not be higher than can be readily assimilated by the natural environment [10]. Given all this, how can we infer whether a given process is sustainable? At first, only qualitative sustainability assessments were considered, and this situation led to inconsistent discrepancies and conclusions when one or more processes were compared with each other. To solve this problem, several metrics of green chemistry and sustainability have been proposed by researchers linked to both industry and academia [11]. As Hollmann said, “calculating is knowing better” [12]. One of

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the main criteria used for the business and investment sector has been Environmental Social Governance. The road is long, and we have progressed continuously. Nevertheless, we will be happy when we no longer need to use the adjectives “green” and “sustainable” because these actions that we currently struggle to incorporate and implement will become the modus operandi. In this time to come, we will refer again to “chemistry” and “development.”

7.3 Biocatalysis is green and sustainable Principle #9 of green chemistry refers to catalysis, where catalytic reagents (as selective as possible) are superior to stoichiometric reagents. Among the classes of catalytic reagents available are organocatalysts, organometallics, metallics, phase transfer catalysts, and biocatalysts, each with advantages and disadvantages. The use of biocatalysts, such as enzymes or whole cells, in the catalysis of chemical reactions is known as biocatalysis [13]. Biocatalytic processes are green and sustainable and can comprise 10 of the 12 principles of green chemistry, as shown in Table 7.2 [14–16]. Figure 1 illustrates the relationship between chemistry, green chemistry, biocatalysis, sustainability, and the SDGs. Enzymes are the catalysts of nature, and they have several characteristics that are attractive for sustainable processes. They come from renewable sources and are biodegradable, biocompatible (some can even be consumed), and not toxic or dangerous [17]. They still act under mild reaction conditions, such as atmospheric pressure, room temperature, and pH close to neutral [18]. Enzymes are also potentially chemo-, regio-, and stereoselective, eliminating, in many cases, the need for protection and deprotection steps of functional groups in a synthetic route [3]. These characteristics result in safer synthetic routes, providing savings in reaction steps with more efficient resources and energy, as well as less waste generation at the end of the process [19]. Although the use of enzymes as biocatalysts started in the early twentieth century, it was only in the late 1980s, with the advent of recombinant DNA technologies, that biocatalytic processes became more widely used on an industrial scale [20]. Enzymes can be cloned into vectors, and thus, their genes can be overexpressed in cells of prokaryotic or eukaryotic organisms such as E. coli or S. cerevisiae, respectively, increasing their production [21]. Currently, with the help of directed evolution techniques, mutations have been introduced into enzymes, adapting these biocatalysts to the conditions of the process, for example, increasing their stability, scope of substrates, and catalyzed reactions [22]. With these technologies, it has become possible to design a perfect enzyme for a given process, and it is no longer necessary to modify the process to accommodate the available enzyme, as was needed 25 years ago [23, 24]. In this way, an enzyme can be designed to accommodate a process that is “green-by-design” [25]. The immobilization of biocatalysts is another crucial factor for their stability to be increased, with a consequent increase in their shelf life and the possibility of reuse [26].

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Table 7.2: The relationship between biocatalysis and the principles of green chemistry. Green chemistry principle

Biocatalysis

 – Waste prevention

Biocatalysts are very selective, avoiding the formation of residues.

 – Atom economy

Due to the selectivity of biocatalysts, there will be fewer steps than in a synthetic route.

 – Less hazardous synthesis

Biocatalysts are not toxic or dangerous, and they are also biocompatible.

 – Safer products by design

Not applicable (principle focuses on the product).

 – Innocuous solvents and auxiliaries

Biocatalytic reactions take place preferably in water.

 – Energy efficient by design

Biocatalytic reactions take place under mild reaction conditions, with temperatures and pressures close to those of the environment.

 – Preferably renewable raw materials

Biocatalysts come from renewable sources.

 – Shorter synthesis (avoid derivatization) Due to the selectivity of biocatalysts, protection and deprotection steps can be avoided.  – Catalytic rather than stoichiometric reagents

Enzymes are catalysts.

 – Design products for degradation

Not applicable (principle focuses on the product).

 – Real-time analysis

Biocatalytic processes can be monitored in real time.

 – Inherently safer processes

Because they are used under milder reaction conditions, the use of biocatalysts is safer.

Figure 7.1: Relationship between chemistry, green chemistry, biocatalysis, sustainability, and the SDGs.

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Owing to directed evolution, advances in genome sequencing techniques, gene synthesis, immobilization of biocatalysts, and advances in bioinformatics, biocatalysis has become more widely employed industrially, mainly by the pharmaceutical industry in the synthesis of APIs (active pharmaceutical ingredients) [27].

7.3.1 Examples of green biocatalytic processes in industry The number of biocatalytic processes used at the industrial level has been increasing in recent decades, with approximately 60 processes in 1990, 134 in 2002, and on the order of a few hundred in 2019 [28]. Among the most successful examples of biocatalytic processes are in the synthesis of APIs, notably, the chemoenzymatic synthesis of montelukast (Singulair), atorvastatin (Lipitor), and sitagliptin (Januvia) (Scheme 7.1) [29, 30]. Montelukast (Scheme 7.1a), commercialized under the name Singulair® by Merck, is a drug with antiasthmatic action. In one of the stages of its synthesis, the enzyme ketoreductase (KRED) was used, which replaces the catalyst (–)-DIP-Cl (chlorodiisopinocampheylborane) previously used in the reaction [31]. The KRED used in the process was engineered to improve its activity regarding the substrate and its stability. The final mutant of this enzyme, called CDX-026, showed a 2,000fold activity increase, and the desired product was obtained with yields >95% and 99.9% ee. Comparing the biocatalytic route with the chemical route previously employed, the researchers observed an increase in yield from 85–90% to 90–98%, an increase in ee from >99% to >99.9%, and a decrease in the use of the catalyst from 150 wt% to 3–5 wt%. In addition, the process mass intensity (PMI) was calculated, defined as the ratio between the amount of the entire material input and the product output quantity, and the process using KRED reduced the PMI from 52 to 34 [38]. Atorvastatin, marketed under the name Lipitor® by Pfizer, is used to treat blood cholesterol levels. As Pfizer’s greatest blockbuster, Lipitor® sales peaked at $12 billion in 2006, and it continues to grossly earn $2 billion per year, even though its patent expired a decade ago in 2011 [32]. The green-by-design biocatalytic process to obtain its side chain used an enzymatic cascade with three enzymes. In the first stage, there was a reduction of ethyl-4-chloroacetoacetate using a KRED and a glucose dehydrogenase used for cofactor recycling. In the second stage, a halohydrin dehalogenase was used to replace the chlorine substituent with a cyano group (Scheme 7.1b). In the previous processes, alkaline reaction conditions and high temperatures (pH 10 and 80 ° C) were used, and the reactions had low yields, resulting in a high formation of coproducts [33]. In the biocatalytic process, the product was obtained with an overall yield >90%, with purity >98% and ee >99.9%. The E-factor for this route was 5.8 without including water and 18 if water was included. The development of this process culminated with Codexis (the company responsible for engineering the enzymes used) winning the 2006 Greener Reaction Conditions Award in the Presidential Green Chemistry Challenge [34].

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Sitagliptin is a drug used to treat type II diabetes, marketed under the names Januvia® and Janumet® by Merck. In the biocatalytic process, an ω-transaminase (ATA-117) from Arthrobacter sp. was used in the reductive amination step to convert the prositagliptin ketone to sitagliptin (Scheme 7.1c) [35]. The biocatalytic process, when compared to the rhodium-based chiral catalyst previously employed for the synthesis of sitagliptin, obtained a 10% increase in global yield, in addition to an increase in productivity (kg/L per day) of 53%, with 19% elimination of total waste formation [36]. The development of this process yielded the Greener Reaction Conditions Award again in 2010 for Codexis in the Presidential Green Chemistry Challenge. In 2012, the Food and Drug Administration approved the implementation of the biocatalytic process for the manufacture of Januvia by Merck [37, 38]. However, the production of APIs is not the only success of biocatalytic processes. Perhaps one of the most successful industrial examples of the application of biocatalysis in the bulk chemical industry is the synthesis of acrylamide, a process that has been carried out for 40 years [39]. Acrylamide is a vital commodity chemical used as a monomer in the production of polyacrylamide, a polymer that has several applications, including in the oil industry, in water treatment, and in the paper and textile industries. The synthesis of acrylamide can be achieved by a chemical or enzymatic process [40]. The chemical synthesis uses high-pressure and energyintense copper catalysis, where the copper catalyst needs to be removed from the reaction medium [41]. In addition, the production of acrylamide is not quantitative and requires recovery of the starting material at the end of the process. The rate of acrylamide formation is lower than that of acrylic acid formation, and to make it worse, byproducts such as ethylene, cyanohydrin, nitrilotris(propionamide), and polymers are formed. Overall, these issues have led to intense efforts in purification steps and, consequently, more waste generated. On the other hand, in the enzymatic process to obtain acrylamide from acrylonitrile using immobilized whole cells expressing nitrile hydratases, the reaction takes place at room temperature and atmospheric pressure, which results in energy savings. The conversion and selectivity are high, generating fewer byproducts and consequently decreasing the efforts in purification and generating less waste, while the immobilized biocatalyst is recovered and reused [42–44]. Enzymatic hydration using nitrile hydratases is by far a greener process than the chemical process, and currently, approximately 600,000 tons of acrylamide are produced per year by this process [47]. The use of biocatalytic alternatives by the chemical industry encompasses areas other than the production of bulk chemicals and APIs. The applications of biocatalysts in the food industry are possibly the oldest use of microorganisms by humankind, producing beverages such as beer, wine, and bread [45]. Another area that uses these catalysts is biofuel production, where the most current research aims at using biomass of lignocellulosic origin as a starting material; additional application areas include the paper, flavoring, cosmetics, and detergent industries [46]. Other examples can be found in [47, 48].

N

O

O

O O

Scheme 7.1: Biocatalytic processes for the synthesis of montelukast (a), atorvastatin (b), and sitagliptin (c).

N

O

GDH

Prositagliptin ketone

N N N F3C

O

OMe

F

F

Cl

F

glucose

NADP

KRED

NADPH

Na+-gluconate

O

c) Sitagliptin

Cl

b) Atorvastatin (lateral chain)

Cl

a) Montelukast

TA

OH O O

KRED N

NC

OH O

Montelukast

O

O

OMe

N N N F3C

NH2

Sitagliptin

N

O

F

F F

Ethyl (R)-4-cyano-3-hydroxybutyrate

HHDH

Cl

OH

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7.3.2 Greening the chemistry and chemical engineering curriculum with biocatalysis One of the most effective and profitable investments to be made for the future is to ensure that new generations of chemists, chemical engineers, and professionals in related fields are thoroughly familiar with the concepts of sustainable chemistry and green chemistry and are encouraged to develop skills and competencies to work according to the demands of sustainable development. In this context, countless initiatives are being adopted to insert the teaching of green chemistry at all levels of education, starting at elementary and high school, proceeding through undergraduate and graduate courses and going beyond the classrooms, reaching the entire community, including administrative areas and services. As an example of some critical initiatives, there are the Global Green Chemistry Initiative (UNIDO, GEF, and Center for Green Chemistry and Green Engineering from Yale University), Green Chemistry Commitment (Beyond Benign Institute), ACS Student Chapter on Green Chemistry, My Green Lab, and many others. It is crucial to offer tools so that the organic chemist can work with biocatalysts and understand what they do, how they work, and how they can be adapted for industrial use, always guided by sustainability and green chemistry principles. Even today, it is not uncommon to find synthetic organic chemists who are unfamiliar with biocatalysis. Few classic organic chemistry textbooks present biocatalysis, mechanisms, and possibilities on an equal footing with reactions catalyzed by metal catalysts, organometallics, organocatalysts, phase transfer catalysts, and acid and fundamental catalysts. In addition to the various review articles that seek to fill this gap through a retrosynthetic approach to biocatalysis, we recommend Nick Turner’s Biocatalysis in Organic Synthesis (The Retrosynthesis Approach), Royal Society of Chemistry; 1st edition (October 1, 2018) to encourage undergraduates, graduate students, and interested researchers [25]. Due to our interest in education and the topics of biocatalysis, green chemistry, and sustainable chemistry, in 2016, we introduced the course “Biocatalysis: fundamentals and aspects of green chemistry,” with great success (course code at UNESP: QO16104T1, 4 h/week, 60 h total/15 weeks). The target audience is undergraduate students majoring in chemistry and chemical engineering, with an average of 25 students enrolled in the course. A general chemistry course is a required prerequisite, while organic chemistry and biochemistry are recommended. This course explores the fundamentals of biocatalysis and how it can help address global human health and environmental issues from a chemistry perspective. Students gain insight into the potential of enzymes to produce organic molecules, enzyme selection and (highthroughput) screening strategies, chirotechnology and its use (especially in the fine chemicals and pharmaceutical industry), examples of whole cell and enzyme immobilization techniques, incorporation of nonconventional media such as ionic liquids, supercritical CO2, and organic solvents in biocatalytic systems, advantages and

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disadvantages of using biorenewables in production processes, and the ability to judge novel processes on the merits of their sustainability metrics. This knowledge is then related to various environmental and human health issues, and the students propose appropriate solutions using green chemistry approaches covered in the course. Students should take an active role in the in-class exercises and class discussions during the semester. They are encouraged to work together on the problem sets, and everyone must turn in their own work. At the end of the semester, we realize students’ fascination for actively inserting themselves in the construction of knowledge on the subject, strengthening their understanding, proposing sustainable solutions, and entering the job market with differentiated training.

7.4 Concluding remarks Many educational institutions, research institutions, NGOs, and the chemical industry actively participate in the effort to meet the goals set out in the 2030 Agenda, contained in the UN 17 SDGs by adopting the principles of green chemistry. These principles lead to the reduction of impacts related to chemistry on human health and the elimination of environmental contamination through sustainable programs dedicated to the prevention of waste generation. It is necessary not only to give visibility to the sustainable solutions promoted by green chemistry but also to increase good practices and encourage schools, universities, research centers, and companies in the sector to become more engaged in this global agenda. In doing so, biocatalysis represents a greener alternative methodology for the synthesis of important organic molecules at academic and industrial laboratories and can be used as a valuable educational tool in theoretical and practical courses.

References [1]

[2]

[3] [4]

Clark, J. H. Green and Sustainable Chemistry: An Introduction. In: Louise Summerton, Helen F Sneddon, Leonie C Jones, James H Clark (eds.), Green and Sustainable Medicinal Chemistry: Methods, Tools and Strategies for the Twenty-First Century Pharmaceutical Industry; The Royal Society of Chemistry, London, 2016, 1–11. doi: 10.1039/9781782625940-00001. United Nations. Report of the World Commission on Environment and Development: Our Common Future; Oxford University Press: Oxford, 1987. https://sustainabledevelopment.un. org/content/documents/5987our-common-future.pdf (accessed 2021-05-20). Horváth, I. T. Introduction: Sustainable Chemistry. Chem. Rev. 2018, 118(2), 369–371. doi: 10.1021/acs.chemrev.7b00721. Cabral, R.; Gehre, T. Guia Agenda 2030: Integrando ODS, Educação E Sociedade; 1st ed., Comissão Permanente de ensino FAAC – Unesp, São Paulo, 2020.

172

[5] [6] [7] [8] [9] [10] [11]

[12] [13]

[14]

[15] [16] [17]

[18] [19] [20] [21]

[22]

[23]

[24] [25]

Iris S. Teixeira et al.

ABIQUIM – Associação Brasileira da Indústria Química. Relatório de Atuação Responsável. https://abiquim.org.br/programas/sistemaGestaoAr (accessed 2021-05-20). Centro de Gestão e Estudos Estratégicos. Química Verde no Brasil: 2010-2030, 2010. Anastas, P. T.; Warner, J. C. Green Chemistry: Theory and Practice; Oxford University Press, New York, 1998. Ministério do Meio Ambiente – Governo Federal do Brasil. http://www.abc.gov.br/zopacas/ informacoes/InstituicaoMMA.aspx (accessed 2021-05-21). Rio +20 Conferência das Nações Unidas sobre Desenvolvimento Sustentável. http://www. rio20.gov.br/sobre_a_rio_mais_20.html (accessed 2021-05-21). Graedel, T. E. Green Chemistry and Sustainable Development. In: Handbook of Green Chemistry and Technology; Oxford, 2002, 56–61. Roschangar, F.; Colberg, J.; Dunn, P. J.; Gallou, F.; Hayler, J. D.; Koenig, S. G.; Kopach, M. E.; Leahy, D. K.; Mergelsberg, I.; Tucker, J. L.; Sheldon, R. A.; Senanayake, C. H.; Deeper, A. Shade of Green: Inspiring Sustainable Drug Manufacturing. Green Chem. 2017, 19(1), 281–285. doi: 10.1039/C6GC02901A. Ni, Y.; Holtmann, D.; Hollmann, F. How Green Is Biocatalysis? To Calculate Is To Know. ChemCatChem. 2014, 6(4). doi: 10.1002/cctc.201300976. Bornscheuer, U. T.; Huisman, G. W.; Kazlauskas, R. J.; Lutz, S.; Moore, J. C.; Robins, K. Engineering the Third Wave of Biocatalysis. Nature. 2012, 485(7397), 185–194. doi: 10.1038/nature11117. Sheldon, R. A.; Brady, D.; Bode, M. L. The Hitchhiker’s Guide to Biocatalysis: Recent Advances in the Use of Enzymes in Organic Synthesis. Chem. Sci. 2020, 11(10), 2587–2605. doi: 10.1039/c9sc05746c. Sheldon, R. A.; Woodley, J. M. Role of Biocatalysis in Sustainable Chemistry. Chem. Rev. 2018, 118(2), 801–838. doi: 10.1021/acs.chemrev.7b00203. Patel, R. N. Green Biocatalysis; 1st ed., John Wiley & Sons, Inc., Hoboken, New Jersey, 2016. Sheldon, R. A. Biocatalysis and Biomass Conversion: Enabling a Circular Economy: Biocatalysis and Biomass Conversion. Philos. Trans. R. Soc. A Math. Phys. Eng. Sci. 2020, 378(2176): 20190274. doi: 10.1098/rsta.2019.0274. Turner, N. J.; O’reilly, E. Biocatalytic Retrosynthesis. Nat. Chem. Biol. 2013, 9(5), 285–288. doi: 10.1038/nchembio.1235. Sheldon, R. A.; Pereira, P. C. Biocatalysis Engineering: The Big Picture. Chem. Soc. Rev. 2017, 46(10), 2678–2691. doi: 10.1039/c6cs00854b. Reetz, M. T. Biocatalysis in Organic Chemistry and Biotechnology: Past, Present, and Future. J. Am. Chem. Soc. 2013, 135, 12480–12496. doi: 10.1021/ja405051f. Bornscheuer, U. T.; Huisman, G. W.; Kazlauskas, R. J.; Lutz, S.; Moore, J. C.; Robins, K. Engineering the Third Wave of Biocatalysis. Nature. 2012, 485(7397), 185–194. doi: 10.1038/nature11117. Bornscheuer, U.; de Souza, R. O. M. A.; Miranda, L. S. M. A Retrosynthesis Approach for Biocatalysis in Organic Synthesis. Chem. – Chem. Eur. J. 2017, 23, 12040–12063 doi: 10.1002/chem.201702235. Badenhorst, C. P. S.; Bornscheuer, U. T. Getting Momentum: From Biocatalysis to Advanced Synthetic Biology. Trends Biochem. Sci. 2018, 43(3), 180–198. doi: 10.1016/j. tibs.2018.01.003. Woodley, J. M. New Frontiers in Biocatalysis for Sustainable Synthesis. Curr. Opin. Green Sustain. Chem. 2020, 21, 22–26. doi: 10.1016/j.cogsc.2019.08.006. Sheldon, R. A.; Brady, D. Broadening the Scope of Biocatalysis in Sustainable Organic Synthesis. Chem. Sus. Chem. 2019, 2859–2881. doi: 10.1002/cssc.201900351.

7 The role of biocatalysis in green and sustainable chemistry

173

[26] Sheldon, R. A.; Brady, D. The Limits to Biocatalysis: Pushing the Envelope. Chem. Commun. 2018, 54(48), 6088–6104. doi: 10.1039/c8cc02463d. [27] Sheldon, R. A.; Pereira, P. C. Biocatalysis Engineering: The Big Picture. Chem. Soc. Rev. 2017, 46(10), 2678–2691. doi: 10.1039/c6cs00854b. [28] Heckmann, C. M.; Paradisi, F. Looking Back: A Short History of the Discovery of Enzymes and How They Became Powerful Chemical Tools. Chem. Cat. Chem. 2020, 12(24), 6082–6102. doi: 10.1002/cctc.202001107. [29] Ferreira-Leitão, V. S.; Cammarota, M. C.; Aguieiras, E. C. G.; de Sá, L. R. V.; FernandezLafuente, R.; Freire, D. M. G. The Protagonism of Biocatalysis in Green Chemistry and Its Environmental Benefits. Catalysts. 2017, 7(1), 9. doi: 10.3390/catal7010009. [30] Narancic, T.; Davis, R.; Nikodinovic-Runic, J.; O’ Connor, K. E. Recent Developments in Biocatalysis beyond the Laboratory. Biotechnol. Lett. 2015, 37(5), 943–954. doi: 10.1007/ s10529-014-1762-4. [31] Liang, J.; Lalonde, J.; Borup, B.; Mitchell, V.; Mundorff, E.; Trinh, N.; Kochrekar, D. A.; Cherat, R. N.; Ganesh Pai, G. Development of a Biocatalytic Process as an Alternative to the (-)-dip-clmediated Asymmetric Reduction of a Key Intermediate of Montelukast. Org. Process Res. Dev. 2010, 14(1), 193–198. doi: 10.1021/op900272d. [32] Axios. https://www.axios.com/lipitor-pfizer-drug-patent-sales-2019-6937cdfb-47f1-46bc8cf0-39e6b88e235e.html (accessed 2021-05-21). [33] Ma, S. K.; Gruber, J.; Davis, C.; Newman, L.; Gray, D.; Wang, A.; Grate, J.; Huisman, G. W.; Sheldon, R. A. A Green-by-Design Biocatalytic Process for Atorvastatin Intermediate. Green Chem. 2010, 12(1), 81–86. doi: 10.1039/b919115c. [34] United States Environmental Protection Agency. https://www.epa.gov/greenchemistry/ presidential-green-chemistry-challenge-2006-greener-reaction-conditions-award (accessed 2021-05-21). [35] Rosenthal, K.; Lütz, S. Recent Developments and Challenges of Biocatalytic Processes in the Pharmaceutical Industry. Curr. Opin. Green Sustain. Chem. 2018, 11, 58–64. doi: 10.1016/j. cogsc.2018.03.015. [36] Savile, C. K.; Janey, J. M.; Mundorff, E. C.; Moore, J. C.; Tam, S.; Jarvis, W. R.; Colbeck, J. C.; Krebber, A.; Fleitz, F. J.; Brands, J.; Devine, P. N.; Huisman, G. W.; Hughes, G. J. Biocatalytic Asymmetric Synthesis of Chiral Amines from Ketones Applied to Sitagliptin Manufacture. Science (80). 2010, 329(5989), 305–309. doi: 10.1126/science.1188934. [37] United States Environmental Protection Agency. https://www.epa.gov/greenchemistry/presi dential-green-chemistry-challenge-2010-greener-reaction-conditions-award (accessed 202105-21). [38] Pharmafile. http://www.pharmafile.com/news/172417/fda-approves-greener-process-januvia -production (accessed 2021-05-21). [39] Jiao, S.; Li, F.; Yu, H.; Shen, Z. Advances in Acrylamide Bioproduction Catalyzed with Rhodococcus Cells Harboring Nitrile Hydratase. Appl. Microbiol. Biotechnol. 2020, 104(3), 1001–1012. doi: 10.1007/s00253-019-10284-5. [40] Prasad, S.; Bhalla, T. C. Nitrile Hydratases (Nhases): At the Interface of Academia and Industry. Biotechnol. Adv. 2010, 28(6), 725–741. doi: 10.1016/j.biotechadv.2010.05.020. [41] Ran, N.; Zhao, L.; Chen, Z.; Tao, J. Recent Applications of Biocatalysis in Developing Green Chemistry for Chemical Synthesis at the Industrial Scale. Green Chem. 2008, 10(4), 361–37. doi: 10.1039/b716045c. [42] Debabov, V. G.; Yanenko, A. S. Biocatalytic Hydrolysis of Nitriles. Rev. J. Chem. 2011, 1(4), 385–402. doi: 10.1134/s2079978011030010. [43] Dorr, B. M.; Fuerst, D. E. ScienceDirect Enzymatic Amidation for Industrial Applications. Curr. Opin. Chem. Biol. 2018, 43, 127–133. doi: 10.1016/j.cbpa.2018.01.008.

174

Iris S. Teixeira et al.

[44] BASF Annual Report, 2016. https://report.basf.com/2016/en/basf-sustainable-future.html accessed in 06/ 03/2021. [45] Tripathi, P.; Sinha, S. Industrial Biocatalysis: An Insight into Trends and Future Directions. Curr. Sustain. Energy Reports. 2020, 7(3), 66–72. doi: 10.1007/s40518-020-00150-8. [46] Chapman, J.; Ismail, A.; Dinu, C. Industrial Applications of Enzymes: Recent Advances, Techniques, and Outlooks. Catalysts. 2018, 8(6), 930–943. doi: 10.3390/catal8060238. [47] Choi, J.-M.; Han, -S.-S.; Kim, H.-S. Industrial Applications of Enzyme Biocatalysis: Current Status and Future Aspects. Biotechnol. Adv. 2015, 33(7), 1443–1454. doi: 10.1016/j. biotechadv.2015.02.014. [48] Wenda, S.; Illner, S.; Mell, A.; Kragl, U. Industrial Biotechnology – the Future of Green Chemistry? Green Chem. 2011, 13(11), 3007–3047. doi: 10.1039/c1gc15579b.

Michal Tomasz Ruprecht

8 The climate education clock When I was young, I played with a kitchen timer waiting for it to ring at zero seconds. The sound was exciting yet scary. Today, I am watching a different clock – not my kitchen timer – called the Climate Clock. This clock, developed by Gan Golan and colleagues, estimates the amount of time left to avoid an increase in global temperatures by 1.5 °C [1]. This figure has been estimated by the scientific community to be a point of no return [2, 3]. If global temperatures rise above this figure, scientists predict that the risks and impacts of climate change will significantly increase [4]. Published models suggest that climate change will impact rainfall and temperature, sea level, marine life, health, food security, and drinking water [5, 6]. The effects of climate change impact nearly every United Nations sustainable development goal [7]. As an undergraduate science student, it is worrisome to see so little being done about the impending effects of climate change. In fact, some scientists suggest that global temperatures will surpass 1.5 °C [3]. The effects of climate change will be lifechanging, especially for my generation. However, my early experience with green chemistry in my high school classroom reinvigorated me by providing me the tools necessary to incorporate climate-friendly principles in the lab [8, 9]. In Chemistry 216, an introductory organic chemistry course at the University of Michigan taught by Ginger Shultz, I worked with colleagues to find an alternative to using dichloromethane in the Wittig reaction, one of the most widely used methods for forming carbon–carbon double bonds [10]. We accomplished our goal of finding an alternative procedure by using ethyl acetate, while also improving the potential environmental impact. The hazard-driven scoring of safety, health, and environment is greatly improved when using ethyl acetate compared to dichloromethane [11]. Based on the 12 principles of green chemistry created by Paul Anastas and John Warner in 1998, the field has transformed how chemists think about the reagents and materials they use in the lab [12]. Teaching students to think similarly has been shown to be an effective method to increase awareness of green chemistry and attitudes toward chemistry [9]. In addition, exercises that challenge students to incorporate green chemistry principles into their lab work strengthen the connections students see between green chemistry and their own environment [13]. At Washington College, Anne Marteel-Parrish found that green chemistry-focused experiences expand students’ creative thinking and problem-solving, enhancing their thought process to include their local and global environment [14]. Other studies have replicated these results, demonstrating increased confidence and interest in science after exposing students to green chemistry [15]. Yet for many of my colleagues, college was the first time they were introduced to green chemistry and other ideas related to climate change. In fact, a 2019 survey https://doi.org/10.1515/9783110723960-008

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found that more than half of high school teachers do not teach students about climate change [16]. Furthermore, a 2018 study analyzing US high school textbooks and materials found that the materials used in the classroom should be improved to include impacts and strategies to combat climate change [17]. The deficits in climate change education, including green chemistry, leave high students without critical knowledge to participate in civic and economic life [17]. The many benefits that come with teaching green chemistry in the classroom should lead to more adoption among educators; however, deficits continue to persist [9, 13–15]. Yet, I and others remain optimistic that educators across the country can better incorporate education focused on sustainability and climate change [19]. Furthermore, a new wave of youth activism around the issue of climate change has made the issue more accessible to young students [20]. Though there is much work to be done, these recent efforts are optimistic signs that climate change, including green chemistry, may become a more frequent topic in the classroom. But, the Climate Clock continues to tick with less time left each day, underscoring the importance of our generation’s largest challenge. As the issue of climate change continues to amplify, so does the issue of educating our youth about climate change and related issues including green chemistry. It is our time to act because there is not much time left on the climate education clock.

References [1] [2]

[3]

[4]

[5]

[6]

Golan, G., et al. The Climate Clock. ClimateClock.World, climateclock.world. Accessed 7 June 2021. McGushin, A.; Tcholakov, Y.; Hajat, S. Climate Change and Human Health: Health Impacts of Warming of 1.5 °C and 2 °C. Int. J. Environ. Res. Public Health. 2018, 15(6), 1123. ProQuest. 7 June 2021. Jacob, D.; Kotova, L.; Teichmann, C.; Sobolowski, S. P.; Vautard, R.; Donnelly, C.; Koutroulis, A. G.; Grillakis, M. G.; Tsanis, I. K.; Damm, A.; Sakalli, A.; van Vliet, M. T. H. Climate Impacts in Europe under +1.5 °C Global Warming. Earth’s Future. 2018, 6, 264–285. doi: https://doi. org/10.1002/2017EF000710. Schaeffer, M.; Hare, W.; Rahmstorf, S., et al. Long-term Sea-level Rise Implied by 1.5 °C and 2 °C Warming Levels. Nat. Clim. Change. 2012, 2, 867–870. doi: https://doi.org/10.1038/ nclimate1584. Santos, D. J. D.; Pedra, G. U.; da Silva, M. G. B.; Guimarães Júnior, C. A.; Alves, L. M.; Sampaio, G.; Marengo, J. A. Future Rainfall and Temperature Changes in Brazil under Global Warming Levels of 1.5 °C, 2 °C and 4 °C. Sustain. Debate. December 2020, 11(3), 57–90. doi: 10.18472/SustDeb.v11n3.2020.33933. Sarma, A. The New IPCC Report on Global Warming of 1.5[degrees]C. Skeptical Inquirer. Jan-Feb 2019, 43(1), 7+. GaleAcademicOneFile,link.gale.com/apps/doc/A567634724/ AONE?u=umuser&sid=bookmark-AONE&xid=c8cf8241. Accessed 7 June 2021.

8 The climate education clock

[7]

[8]

[9] [10] [11]

[12] [13] [14] [15]

[16]

[17]

[18] [19]

[20]

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Wysokińska, Z. Millenium Development Goals/UN and Sustainable Development Goals/UN as Instruments for Realising Sustainable Development Concept in the Global Economy. Comp. Econ. Res. 2017, 20(1), 101–118. doi: http://dx.doi.org.proxy.lib.umich.edu/10.1515/cer-201700068. Pothoof, J.; Ruprecht, M.; Sliwinski, B. D.; Sosnowski, B. M.; Fitzgerald, P. R.; Kosmas, S.; Benvenuto, M. A. Synthesis of “Three-legged” Tri-dentate Podand Ligands Incorporating Long-chain Aliphatic Moieties, for Water Remediators, and for Isolating Metal Ions in Nonaqueous Solution. Phys. Sci. Rev. 2018, 3(11), 20180076. doi: https://doi.org/10.1515/psr2018-0076. Ballard, J.; Reid Mooring, S. J. Chem. Educ. 2021, 98(4), 1290–1295. doi: 10.1021/acs. jchemed.9b00312. Green Organic Chemistry; Strategies, Tools, and Laboratory Experiments. Scitech Book News 09 2003ProQuest. 7 June 2021. Prat, D.; Wells, A.; Hayler, J.; Sneddon, H.; McElroy, C.; Abou-Shehada, S.; Dunn, P. CHEM21 Selection Guide of Classical – and Less Classical – Solvents. Green Chem. 2015, 18. doi: 10.1039/C5GC01008J. Anastas, P.; Warner, J. Green Chemistry. Theory and Practice; Oxford University Press: New York, 1998. Levy, I. J.; Haack, J. A.; Hutchison, J. E.; Kirchhoff, M. M. J. Chem. Educ. 2005, 82(7), 974. doi: 10.1021/ed082p974. Marteel-Parrish, A. E. J. Chem. Educ. 2007, 84(2), 245. doi: 10.1021/ed084p245. Karpudewan, M.; Roth, W. M.; Ismail, Z. The Effects of “Green Chemistry” on Secondary School Students’ Understanding and Motivation. Asia-Pacific Edu. Res. 2015, 24, 35–43. doi: https://doi-org.proxy.lib.umich.edu/10.1007/s40299-013-0156-z. Kamenetz, A. Most Teachers Don’t Teach Climate Change; 4 In 5 Parents Wish They Did. NPR, NPR, 22 Apr. 2019, www.npr.org/2019/04/22/714262267/most-teachers-dont-teach-climatechange-4-in-5-parents-wish-they-did. Meehan, C. R.; Levy, B. L. M.; Collet-Gildard, L. Global Climate Change in U.S. High School Curricula: Portrayals of the Causes, Consequences, and Potential Responses. Sci. Ed. 2018, 102, 498–528. doi: https://doi.org/10.1002/sce.21338. Corcoran, P. B.; Weakland, J. P.; Wals, A. E. J., eds. Envisioning Futures for Environmental and Sustainability Education; Wageningen Academic Publishers, 2017. Whitehouse, H. Envisioning Futures for Environmental and Sustainability Education Peter Blaze Corcoran, Weakland, J. P; Arjen, E. J. W., Wageningen, Netherlands: Wageningen Academic Publishers, 2017. Aust. J. Environ. Educ. 2018, 34(3), 290–292. doi: 10.1017/ aee.2018.30. Zummo, L.; Gargroetzi, E.; Garcia, A. Youth Voice on Climate Change: Using Factor Analysis to Understand the Intersection of Science, Politics, and Emotion. Environ. Educ. Res. 2020, 26(8), 1207–1226. doi: 10.1080/13504622.2020.1771288.

Scott Milam

9 LOL diagrams 9.1 Modeling instruction I participated in five workshops for modeling instruction in the last 6 years. Whether I was a participant or facilitator, I came away with an abundance of pedagogical improvements. Prior to modeling instruction, I would work to find the perfect explanation that would help every student understand chemistry. Now my focus is on determining what students think and building from there. When students observe phenomena, they have ideas about what they saw. They use mental models to communicate these conceptions. Modeling instruction seeks to help students communicate their mental models while the teacher works to enhance student models through questioning and revision [1]. A chemistry modeling unit begins with students gathering data or observations through experiments. They are then tasked with organizing the data onto a whiteboard. The teacher leads a class discussion about the whiteboards where students describe what they observe for different student models of the experimental evidence. The teacher uses “talk moves” [2] to encourage students to express and enhance their ideas about what they observed. Next, a task is assigned, where students use their models to solve problems. The models are revised as needed in a cyclical fashion. The cycle involves articulating the model, reflecting, deploying the model, and repeating these steps up until the final assessment. Common examples of models include slope, particle representations, equations, graphs, and organizational tools. Often multiple representations are combined into a single model such as density. This helps students to make connections between the macroscopic, symbolic, and particulate levels [3]. Novice students require practice to transition between these different viewpoints. Modeling instruction emphasizes all three while traditional instruction tends to focus on the symbolic level. The symbols in chemistry are abstract, thus student learning is often via association and not authentic understanding. The modeling curriculum has some creative organizational tools that are used. BCA (before, change, after) tables are utilized in stoichiometry. These tables are similar to ICE charts (initial, change, equilibrium) that have been used in equilibrium. In physics, LOL charts are used to track energy changes. The LOL charts are included as part of the chemistry curriculum where both LOL and LOLOL diagrams are used.

Scott Milam, Plymouth-Canton Educational Park Michigan 48187 USA, e-mail: [email protected] https://doi.org/10.1515/9783110723960-009

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9.2 Unit 3 sequence Modeling pedagogy does come with a structured curriculum. Thermochemistry first appears in unit 3, where students learn about basics of energy changes. In unit 7, students connect chemical potential energy to chemical reactions, and in unit 9, students connect enthalpy to stoichiometry. The initial phenomena in unit 3 begins with the teacher displaying a tiny beaker (50–100 mL) with boiling water next to a medium-sized beaker (250–300 mL) with warm (60 °C) water. Which beaker is hotter?

Figure 9.1: A tiny beaker with boiling water and a medium beaker with warm water.

After initial ideas of a student have been voiced, the teacher pours the medium beaker into a larger beaker of room temperature water. The temperature change is noted. The teacher then pours the small beaker into a second larger beaker of room temperature water. The temperature change is noted. Which beaker (tiny or medium) was hotter? Both the tiny beaker and the medium beaker present valid arguments that they are hotter. The tiny one has the higher initial temperature while the medium one can heat up the room temperature water more. This highlights a glaring issue in thermodynamics education. The language we use commonly lacks precision needed to differentiate this question. Hotter could refer to having a higher temperature, having a larger amount of thermal energy, or even reflect our perception. This discussion can move further to what is meant by temperature, heat, or thermal energy. The second lesson shows students to heat ice water while measuring the temperature at regular intervals. The students predict what the plot of temperature versus time will look like and then take data to compare with their predictions. These plots are constructed onto whiteboards where students can discuss the resulting heating curves. Questions can direct students in several directions. They can focus on why temperature fluctuate during melting as the mixture is stirred. They can ask students what would have changed had the amount of initial ice-water changed or the hot plate setting altered. But the two key questions are why there are three different sections to the plot, and why does the temperature not change while the water boils?

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This discussion concludes with the need for two applications of energy for the water particles. Thermal energy occurs when the water is heated, and the particles move faster. Phase energy occurs when the water is heated, and the particles become further spaced apart (we are ignoring the complicating factors of liquid water being denser for now). During boiling, the hot plate particles are colliding with the water particles at high speeds and yet the water particles do not move faster. This implies that there is some type of force preventing those particles from speeding up. For now, this force is labeled as stickiness instead of intermolecular forces.

9.3 LOL diagrams Once we have established what particles look like when thermal and phase energies change, we are ready to introduce the LOL diagram via direct instruction. The first L shows the initial amounts of thermal and phase energy. The second L shows the final amounts after a transformation has taken place. The O represents the system and shows whether energy has entered or left the system.

Figure 9.2: LOL diagram for a room temperature can of pop being frozen.

A flexible scale is set to determine how many bars will be used for phase (Table 9.1) and thermal energy (Table 9.2). The justification for having a larger gap of phase energy from liquid to gas than solid to liquid is based on the evidence in the experiment where we melt ice and boil water. There must be a larger input of phase energy for vaporization because it requires much more time to boil the water than to melt the ice. The bars used for thermal energy are intended to be qualitative and not quantitative. The intent is to show how thermal energy changes. So a change in temperature from 100 to 70 °C would use 3 bars for 70 °C. But a shift from 40 to 70 °C might use 4 bars for 70 °C. The key is to focus on the direction of energy changes and conservation. When students begin calculating with specific heat capacity constants, some have few concrete details to connect those calculations with. The LOL diagrams help students by constructing a formal organization of energy during common phenomena

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Table 9.1: Eph bars for an LOL diagram. State of matter

Eph bars

Solid



Liquid



Gas



Table 9.2: Eth bars for an LOL diagram. Temperature (°C)

Eth bars





 (room)







Figure 9.3: LOL diagram for hot water cooling down to room temperature.

that the students have experienced. When we look at student errors in mathematical reasoning, it is not a mathematical failure, but a lack of understanding of temperature, heat, and specific heat capacity. Students use these values interchangeably. Students struggle to differentiate the units of them. The LOL diagram can be the first step at supporting those students to be successful in understanding what they are doing when they perform calculations. When we progress to calculations that involve multiple steps (IE heating water from room temperature through vaporization of the entire sample), we find substantial student confusion. The lack of a consistent algorithm along with a lack of understanding about the concepts causes students to experience cognitive overload. Teachers often couple heating curves with these multistep calculations to provide students an organizational system that helps them identify key features of the calculation. The LOL diagram does that as well, but in much simpler terms. There are no slopes needed for LOL diagrams, and there is less variability between LOL diagrams of

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different materials. Because the LOL diagrams only focus on energy changes, they are easier for students to integrate into their prior knowledge. But ideally a student would learn about LOL diagrams in conjunction with heating curves so they can also grapple with the higher level thinking that heating curves provide opportunities for. Heating curves show how temperature responds to heating or cooling. The rate of heating, the mass of the substance, and the type of substance all influence the slopes of the curve. Students not only struggle with how modifications to those features influence the slope, but they also struggle to convert between a heating curve that has temperature as the y-axis and heat capacity that has temperature as the xaxis (Figure 9.4). Many of these students have little to differentiate heat and temperature in the first place.

Figure 9.4: Substances A and D have higher heat capacities.

The first graph (Figure 9.4) shows heat (Q) being applied to substances A and B. A changes temperature less than B for a given quantity of heat. The slope of these two lines is the heat capacity and would be the specific heat capacity if there was 1 g of A and 1 g of B. The second graph (Figure 9.4) has the axes flipped as they would be in a heating curve. Now the inverse of the slope shows higher heat capacity. D changes temperature less for a given quantity of heat. Heating curves function well to show the plateau in temperature that occurs during a phase change. But they obscure the relevance of the slope, which can make them a very confusing tool to use to organize energy changes around. The design of the LOL has multiple features that help clarify confusion for students. The L components lead the student to focus on what the system is at the beginning and the end. How you get from point A to point B is irrelevant when dealing with state functions which are common in thermodynamics. The O component helps students focus on the system and surroundings. This is critical. If we think about the perspective of a novice student, they can easily confuse which is being discussed. Imagine a teacher who tells their class that melting an ice cube is endothermic. That makes sense to the student since they realize you have to put energy into an ice cube to melt it. But later in that class the teacher may talk about an exothermic reaction where the solution gets warmer.

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This example can be disconcerting to a novice because it conflicts with their conception of hot and cold. The ice cube was being heated (endothermic) while the solution was heated (exothermic). What gives? The ice cube is the system. The solution is the surroundings with regard to the chemical reaction. The LOL diagram not only emphasizes the nature of systems and surroundings but also emphasizes that the gain of one is a loss for the other. Every endothermic process is accompanied by an exothermic change somewhere else. If the system increases in energy, the surroundings decrease in energy. Our perspective of heat can be greatly clarified by being explicit with what happens to both. This emphasizes heat as a transfer more so than the energy itself. The O also forces us to identify what we think the system is. Going back to the example of an exothermic reaction happening in solution, why is the solution not the system? There is a very fine line between the solution and the chemical components of the solution. When we talk about a chemical reaction, we could even include the interactions between the solute and the solvent. But what is happening is that the chemical reaction causes the product particles to speed up. This increase in motion is then transferred to the solution particles via heat. Therefore, it makes sense for us to consider the solution as the surroundings even with the close proximity to the chemical system. This example of a chemical reaction in solution shows that there is a complexity to the step-by-step changes that occur often is omitted from chemistry instruction. Fortunately, the LOL diagram comes with an extension that makes these questions and observations difficult to ignore.

9.4 LOLOL diagrams The LOL diagram is useful for thermal and phase energy changes. The LOLOL diagram is designed to analyze energy changes during a chemical reaction. Thermal energy remains, but phase energy has been replaced by chemical energy. By chemical energy we mean the energy resulting from electrostatic attractions and repulsions between charged particles in a chemical system. Chemical energy is difficult to measure directly, so we instead observe changes in chemical energy by tracking the other forms of energy during reactions. The LOLOL diagram breaks up the chemical reaction into three times. The initial time is before the reaction occurs, the final is after the reaction has happened and the temperature has settled. The middle time varies depending on the sequence of the reaction. For some endothermic reactions, the reaction is initiated by mixing the chemicals. An example of this would be vinegar and baking soda being mixed. Other endothermic reactions begin by heating. The LOLOL diagram differentiates these two:

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NaHCO3 ðsÞ + HC2 H3 O2 ðaqÞ ! H2 O ðlÞ + CO2 ðgÞ + NaC2 H3 O2 ðaqÞ

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Δ H = +

Figure 9.5: LOLOL diagram showing an endothermic reaction between baking soda and vinegar.

For the vinegar and baking soda, the reaction is started when the chemicals mix. The system begins at room temperature, so we start with 2 bars of thermal energy and 2 bars of chemical energy (L 1). Starting with 2 bars of chemical energy is common so that chemical energy can increase or decrease since we do not have much knowledge about how much we start with. As the reaction proceeds, the system temperature drops. The temperature did not drop because of external cooling, rather there must have been a conversion from thermal to chemical energy (L 2). It can be pointed out that this change occurs via particle collisions to begin framing future units on kinetics. After the reaction has completed, the products will then warm back up to room temperature as energy moves from the surroundings to the system (O 2). It is this point where we see the endothermic nature of the reaction. The final mixture has 2 bars of thermal energy with 3 bars of chemical (L 3). This reaction can easily be done in the classroom by having students put a small amount of baking soda and vinegar into opposite corners of a sandwich baggie. As the chemicals are mixed, they can feel the mixture getting colder. This of course means that energy is moving from their hands to the chemical system. Their hands experience an exothermic change while the system experiences an endothermic change. Heating sodium carbonate is also an endothermic reaction, but there are some key differences in the LOLOL diagram (Figure 9.6). For this reaction, the reaction becomes spontaneous at a temperature above room temperature. The sign for ΔH° is + and ΔS° is also +, which means that ΔG° will be negative at high temperatures only. Unlike vinegar and baking soda, that temperature is well above room temperature. The reaction must be heated to occur. This begs the question, what exactly happens when the system is heated? The heating occurs via conduction. So high-energy particles from the surroundings collide with the sodium carbonate particles. The first step in this reaction is therefore an increase in thermal energy of the system via heating from the surroundings. We start with a room temperature sample with 2 bars of thermal and 2 bars of chemical energy (L 1). After the thermal energy has increased via heating (O 1) to 4 bars (L 2), the collisions between sodium carbonate particles become more energetic.

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Now the chemical reaction takes place. The end result is product molecules that are at a lower temperature than they were prior to the reaction (L 3). The decrease in thermal energy (4–2 bars) is offset by a gain in chemical energy (2–4 bars). This conversion occurs without energy transfer to or from the surroundings: Na2 C03 ðsÞ + kJ ! Na2 OðsÞ + CO2 ðgÞ

Figure 9.6: LOLOL diagram showing an endothermic reaction where sodium carbonate is heated.

Notice the learning opportunities that the LOLOL diagrams present that otherwise might not be addressed. Some endothermic reactions initially involve heating and others get colder as the reaction proceeds. The exchange of energy with the surroundings always involves thermal energy and not chemical energy. The conversion of thermal and chemical energy is due to collisions between the particles in the system. And students get a front row seat to the idea that chemical energy is never measured directly. Instead changes in the environment are used to deduce what changes in chemical energy occur. This is a valuable lesson in that chemical energy is a very vague term since students are likely not to be familiar with the force responsible for the potential energy, electrical force. The final LOLOL diagram is for an exothermic reaction. You might find it helpful to try and construct the LOLOL diagram now before looking below. Remember that the LOLOL diagrams are not focused on kinetics and do not account for activation energy. It can be helpful for the teacher to consider the initial starting point for a combustion reaction to be immediately after the flammable material has been ignited. In the LOLOL diagram for the exothermic combustion of methane we start with our reactants at room temperature. We assign 2 bars of thermal energy and 2 bars of chemical energy (L 1). After the reaction is initiated, we observe a temperature increase as the chemical reaction occurs. This increase is a result of the chemical reaction and not due to heating by the surroundings. Therefore, we show a tradeoff in chemical energy decreasing to 1 bar while thermal energy increases to 3 bars (L 2). Because the system is now at a higher temperature than the surroundings, energy moves from the system to the surroundings (O 2). The end result is a room temperature mixture of products (L 3):

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CH4 ðgÞ + 2O2 ðgÞ ! CO2 ðgÞ + 2H2 O ðgÞ + kJ

Figure 9.7: LOLOL diagram for the combustion of methane.

The LOLOL diagram sets up the teacher to extend student’s thinking at the particle level. Consider the exothermic combustion of methane: What is happening to cause the particles to increase in thermal energy? What exactly would an animation showing the conversion of chemical to thermal energy look like? What would we expect student models of their understanding of what is happening? When a student has a limited understanding of energy, they think of it in the caloric theory. The object gains energy and therefore now it is faster. In the caloric model, the student would not be restricted from having energy transfer directly from the surroundings to become chemical energy (as opposed to transferring as thermal energy which is then converted to chemical energy). This model is often used in biology and earth science, where students track energy through a long series of changes. The LOLOL diagram can be used to challenge and revise this misconception by emphasizing two different moments on the diagram and having students articulate what must change at the particle level between those two times. A skilled teacher can direct students to verbalize the role of collisions in these energy changes. The reality is that energy is an abstract description of what happens, and the convenience of using energy can limit the ability of students to make concrete connections with what occurs. The LOLOL diagram is a useful tool to help students construct more concrete images of the changes taking place.

9.5 Cognitive science behind LOL diagrams The purpose of education is for a permanent change in the brain to occur. What will students remember after spending 2 weeks using LOL diagrams, heating curves, and doing calculations? The heating curves will most likely impart that temperature is constant during a phase change. This is an unusual feature that prompts curiosity in the students as they negotiate with the evidence. Does the temperature go up a little bit? What about right when it starts to melt or starts to freeze?

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Calculations are inconsistent. Some students learn how to follow the algorithms and then promptly forget any conceptual components after the exam. In my view, the long-term learning is most likely focused on the fact that different materials change temperature differently when heat is applied. It takes more energy to change the temperature of water than of a metal. Calculations ideally would also involve some permanent brain changes differentiating heat and temperature. Heat and temperature have precise definitions that overlap significantly. Calculations can be an effective way to differentiate them. What then do students retain after using LOL and LOLOL diagrams? The most obvious piece is an emphasis on systems and surroundings. Not only do the diagrams highlight the flow of energy in and out of the system, but they also raise questions about what the system in a chemical reaction is. The diagrams rely heavily on conservation. When chemical energy changes occur, we use changes in thermal energy to predict what happened. Without LOLOL diagrams, most students read the chemical energy changes from an enthalpy value or in a thermochemical equation. Neither of these provide the student a clear path to connecting how the chemical energy changes trade off with the thermal energy. Note how LOL and LOLOL diagrams connect to concrete examples such as experiences in real life, experimental evidence, and particle diagrams. These diagrams also emphasize multiple times during a change. A reaction energy diagram is also used in connection with endothermic and exothermic reactions. A reaction energy diagram is ambiguous about the thermal energy. We see the chemical potential energy mapped out, but the conservation of energy and thermal energy components are often left to the imagination. Chemistry teachers are notorious for complaining about students not knowing that breaking bonds is endothermic, but without an LOLOL diagram there are many missing pieces that allow students to maintain their misconceptions. The emphasis on systems and surroundings allows the student to connect energy changes at the particle level and at the macroscopic level [4]. How does the energy move from the chemical system to the water in the solution? Via collisions. A student who thinks of what the particles look like in the initial and final states is able to realize that molecular motion decreases when thermal energy decreases. This can cause the student to wonder about how that motion change occurs. The emphasis on systems and surroundings can also make it easier to point out to students’ systematic errors in experiments. If we run a coffee cup calorimeter experiment, how much energy transfers to or from the polystyrene cup? A good criticism of chemical education is that it can be too abstract with too many symbols. LOL diagrams help address this by providing a scaffolded organizational tool. This allows students to begin a problem by searching for the initial and final conditions. It identifies three types of energy and how each type changes chemicals at the particle level. Students have much more to draw from when they begin doing calculations or lab experiments.

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Figure 9.8: LOL diagrams for hot metal being added to room temperature water.

Consider a 50.0 g sample of hot metal held in boiling water until it reaches an internal temperature of 100 °C. When the hot metal is moved into an insulated cup with 50.0 g of room temperature water, the water rises in temperature a small amount. The energy moves from the hot metal to the room temperature water. The amount of energy lost by the metal is equivalent to the energy gained by the water. Yet the temperature changes are wildly different. This is a common observation in our lives. The same input of energy into different substances results in different temperature changes. Two substances heated to the same temperature release different amounts of energy as they cool. But explaining this phenomenon is not simple. How is it possible at the particle level for a collision to result in a water particle speeding up slightly while the metal slows down considerably? The LOL diagrams open a new view that exceeds what students will pull from 4.18 J/(g °C).

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References [1] [2]

[3] [4]

Dukerich, L. Applying Modeling Instruction to High School Chemistry To Improve Students’ Conceptual Understanding. J. Chem. Educ. 2015, 92(8), 1315–1319. doi: 10.1021/ed500909w. Cartier, J. L.; Smith, M. S.; Stein, M. K.; Ross, D. K. 5 Practices for Orchestrating Productive Task-based Discussions in Science. Reston, VA: National Council of Teachers of Mathematics, 2013. Gabel, D. Improving Teaching and Learning through Chemistry Education Research: A Look to the Future. J. Chem. Educ. 1999, 76(4), 548. doi: 10.1021/ed076p548. Ibid (Gabel).

Ashley M. Smith and Edward P. Zovinka

10 Green chemistry teaching and research at a small, Catholic university Abstract: Green chemistry, while often discussed in the context of industry, must also factor into a comprehensive undergraduate education. In teaching chemistry at a small, Catholic university, the curriculum can be tailored to incorporate not only green chemistry principles but also the United Nations Sustainable Development Goals (SDGs) from early general chemistry laboratories to more advanced independent study projects for senior chemistry majors. This chapter discusses methods to incorporate green chemistry and the SDGs into undergraduate education, ranging from student research projects to student-led community outreach events. Keywords: pollution reduction, undergraduate research

10.1 Introduction At first glance, the United Nation (UN) sustainable development goals (SDGs), including no poverty, zero hunger, and gender equality, sound like they are unattainable by typical students, educators, or community members [1]. However, upon further reflection, it becomes evident that as a global citizen, it is everyone’s responsibility to do their part in working toward the achievement of these goals. Importantly for chemists at Saint Francis University (SFU), the SDGs match the Goals of Franciscan Higher Education. “Respect for the Uniqueness of Individual Persons,” “Service to the Poor and Needy,” and “Reverence for All Life and Care of Creation” are just three of the eight goals that clearly align with the SDGs. While strides have been made in implementing green chemistry principles throughout industry and academia, advances still need to be made to minimize pollution, reduce the use of harmful chemicals in syntheses, and maximize resource efficiency [2–4]. A critical component of meeting the UN SDG will be the effective implementation of green chemistry principles by emerging young scientists who have a strong background in identifying, analyzing, and applying these principles in both teaching and research settings. To produce such graduates, green chemistry principles must be taught early and often throughout the undergraduate career [5–7]. Upon graduating high school and entering their undergraduate education, students have a superficial understanding of green chemistry. Students know they

Ashley M. Smith, Edward P. Zovinka, Department of Chemistry, Saint Francis University, Loretto, PA 15940-0600, e-mail: [email protected] https://doi.org/10.1515/9783110723960-010

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should recycle newspapers and plastic water bottles, turn off the lights when they leave a room, and not let the water run while brushing their teeth. However, it is imperative that as their science education progresses, their understanding of green chemistry must also evolve into an ability for advanced application [8]. They not only need to conserve water and energy but also chemical solvents and reagents. They cannot just recycle plastic and paper but need to consider the life cycle of their synthetic products. By emphasizing and implementing green chemistry principles throughout their undergraduate classroom and research experience, they will be well equipped to apply innovative green solutions to challenges in their future careers. From their initial general chemistry laboratory up through their senior year, students can be introduced to various sustainability goals in lecture courses, teaching labs, research experiences, and outreach opportunities. The UN outlines quality education as SDG 4, to ensure inclusive and equitable quality education and promote lifelong learning opportunities for all [1]. Starting with their first chemistry course, students are taught not only the basic information pertaining to chemistry (e.g., properties of matter, gas laws, and solubility rules) but also how to think critically, analyze a problem, work in teams, and creatively come up with appropriate solutions. By teaching the students how to think through a problem, they are encouraged to become lifelong learners who value the input of others. Through both undergraduate research and laboratory courses, students gain hands-on experience with chemical synthesis, experimental design, and problem solving. They can also consider SDG 12 – responsible production and consumption, ensuring sustainable consumption and production patterns [1]. As young students, they primarily complete instructor-designed experiments to address specific questions and follow outlined procedures. Reference is made to the reagent choices, where relevant, and inherently safer chemistry for accident prevention, one of the 12 principles of green chemistry, is emphasized. As the students take ownership of their projects and evolve into independent researchers who design their own experiments, they are encouraged to adhere to the green chemistry principles including waste prevention, safer solvents, and less hazardous chemical syntheses [2]. In addition to gaining independence in planning and executing experiments during their independent research projects, throughout their chemistry education students are encouraged to consider how their work can benefit the environment and address SDG 15 – life on land, to protect, restore, and promote sustainable use of terrestrial ecosystems, sustainably manage forests, combat desertification, and halt and reverse land degradation and halt biodiversity loss [1]. From cleaning up litter around the community to research based on acid mine drainage remediation, students work to protect and restore the ecosystems surrounding them while they are in college and take this consideration for the natural world with them upon graduation. A final SDG that can be emphasized throughout a student’s educational career is partnership for goals, SDG 17, to strengthen the means of implementation and revitalize the global partnership for sustainable development [1]. Whether through

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outreach with various community groups or research-based collaboration within the university and outside of it, students are shown the value of working together with diverse personalities and differing opinions. By partnering together, goals can be met in a collaborative and creative way for the betterment of both the students and the global community. From a student’s first chemistry lab through graduation, principles of green chemistry need to be emphasized early and frequently to allow students to evolve from a simplistic understanding of sustainability to a more sophisticated approach. In this chapter, we will elaborate on how green chemistry principles and the UN SDGs can be effectively employed in both undergraduate teaching and research environments to equip students with the tools to be lifelong learners who are considerate of the global environment.

10.2 Research Research has traditionally been an important pillar of an academic career, providing a way to express creativity, support lifelong learning, encourage positive growth, and teach new ways of performing chemistry. Green chemistry and SDGs provide many opportunities for faculty to delve into new research areas, whether as a reinterpretation of traditional methods or as the exploration of new ways to reach chemical goals. In the following section, the greener synthesis of metalloporphyrins, the catalytic application of metalloporphyrins, and the remediation of acid mine drainage are discussed. Each of the research projects developed when we embraced our Franciscan goals, green chemistry, and SDGs.

10.2.1 SDG 12 – responsible production and consumption As chemistry major, the students are mentally prepared and focused on performing and completing chemical reactions. Green chemistry and the SDGs provide a framework for faculty to rethink laboratory experiments and teach their students a more responsible way of reaching desired chemical goals. The integration of microwave reactors and the use of catalysis have both provided effective means of introducing SDG 12 methods into our inorganic and organic teaching laboratories as well as the outlined research.

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10.2.1.1 Green chemistry and microwave Most people use microwave ovens in their kitchens because they are easy to use and fast! The same is true in the chemistry laboratory, since microwave reactors make chemical reactions proceed much faster as they focus the energy directly at the reactants and do not rely on conduction or convection to transfer energy to the reactants [9]. Microwaves force polar molecules to move so that they orient to the alternating electric fields of the microwaves. As the molecules move, heat is generated through friction, rotation, and collisions. Since the microwave reactors directly impact the reacting molecules, less energy is required for faster reactions. Often a reaction is completed in a fraction of the time, using less energy than an old-fashioned light bulb. While the possibilities for using microwaves to speed up chemical reactions was quickly embraced by organic chemists, inorganic chemists were slower to study the benefits of microwave technology, possibly because everyone knows you cannot put metals into a microwave! However, as long as the metals are dissolved in solution, the microwave reactor works effectively and has become more mainstream [10]. In our case, microwave reactors were applied to inserting metals into porphyrin ligands. For many years, our research focused on the synthesis of metalloporphyrins as models of metalloenzymes. The traditional method of metalating porphyrins entailed refluxing metal salts in acetic acid or tetrahydrofuran for 30–180 min. Not only is a significant amount of energy expended to heat the reaction vessel for such extended periods of time, but a large amount of potable water is put down the drain. Microwaves opened up a new avenue of research for our primarily undergraduate institution (PUI) department, so we wondered: could we use microwaves to help metalate the porphyrin ligands? The answer appeared to be yes [11]. Not surprising, research at any PUI proceeds more slowly as undergraduate students are not focused solely on the research project; classes, job/graduate school preparation, and social aspects also consume many students’ attention. However, this pace is not all bad, as the project can positively influence many students over time. The metalation of porphyrin ligands was completed over a several year period and required initial patience as grant and department money was gathered to purchase a microwave reactor. Once a microwave reactor was obtained, the metalation project allowed a number of undergraduates to study a variety of metals on porphyrin ligands, enabling the publication of a general study [12]. The students inserted a variety of metals (e.g., Ni2+, Fe3+, Co2+, Cu2+, and Mn2+), into the biologically relevant porphyrin ligand tetraphenylporphyrin (H2TPP) using only ethyl acetate and ethanol as solvents, sometimes with direct crystallization of the pure product. In addition to studying microwave methodology, they learned to use safer solvents while using less energy to accomplish their chemical goals. Other professors observed the student excitement arising from the research project and chose to adapt the technique to their laboratory experience. Another positive result from studying microwave reactions was the integration of microwave reactions across several classes.

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10.2.1.2 Moving to mechanochemistry Yet chemists continued to find ways to make the metalation even greener, using mechanochemistry [13]. Mechanochemistry is the use of physical grinding, completely avoiding the use of solvents to complete a chemical reaction [14]. Many reactions can be completed by simply using a mortar and pestle, think of an alchemist or an apothecary! However, metalating a porphyrin ligand needs more energy than can be provided through the use of a mortar and pestle, requiring the use of a mixer mill [15]. In fact, with a large enough jar (~10 mL) and at least five mixing balls, one can metalate the porphyrin ligand in 15 min with no solvent at all, advancing our chemical toolbox even closer to sustainable chemical reactions.

10.2.1.3 Using the metalloporphyrins Catalysis is one of the tools available to chemists to more responsibly prepare needed materials, and metalloporphyrins can be used to catalytically functionalize organic feedstocks. Since naturally existing metalloporphyrins often serve as catalysts (e.g., cytochrome P450), we could model the good use of a product (our metalloporphyrins from the previous section) by catalyzing the functionalization of simple organics. Undergraduate students were able to explore the use of metalloporphyrins to create a functionalized organic (an epoxide) from a cyclic alkene using a metalloporphyrin catalyst and hydrogen peroxide [16]. By tracking the reaction by gas chromatography-mass spectrometry and ultraviolet–visible (UV–vis) spectroscopy, we were able to show the catalytic formation of the desired product. A useful material, an epoxide, was created by using the metalloporphyrin synthesized by either microwave or mechanochemical methods, demonstrating responsible production and consumption. The project was revised and updated to reflect continued adaptation of the activity [17]. 10.2.2 SDG 15 – life on land Humans have been extracting materials such as coal from the ground for thousands of years in order to make desired products. However, the very action of digging a mine creates the conditions for a great deal of pollution, now known as abandoned mine drainage (AMD). Once a mine is opened, the strata are exposed to both oxygen (oxidizing agent) and water (dissolution and transport agent). Pyritic materials, such as FeS2, chemically react to produce sulfuric acid, lowering the pH of the water and releasing metal ions into a water system. Lowering the pH damages the ecosystem close to the mine efflux while the metals precipitate downstream, coating the streambed with metal hydroxides (e.g., Fe(OH)3) killing off benthic life. Without the bottom of the food chain, the whole ecosystem is destroyed.

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SFU is located in South Central Pennsylvania, USA, where the legacy (and continued!) coal mining presents the opportunity to study AMD and help restore water systems back to conditions that can support macroinvertebrates and aquatic life. Once remediated, the water can also be used in municipal drinking systems, increasing the area’s water sustainability. Remediation can be completed either actively or passively. Active remediation requires active monitoring, the continuous injection of material, and electricity to run the equipment. Passive remediation takes advantage of natural resources, such as limestone and gravity, to reduce the acidity as well as remove metal ion pollutants [18]. Passive methods have the advantage of using less energy and fewer synthetic chemicals. Open Limestone Channels (OLC) is the passive remediation method we have been studying for efficacy. OLCs can be set up in a variety of ways, but it is common to dig a channel/ trench from the mine discharge location to a precipitation pond (Figure 10.1). The channel or trench is filled with limestone (mostly CaCO3) rock that neutralizes the acidic discharge water. As the pH is increased, the dissolved metal ions are forced to precipitate out of solution. When implemented correctly, the OLC will both neutralize the acid and remove metal ions. Conveniently, once an OLC is constructed, less monitoring and maintenance is needed than an active remediation site, requiring less energy and chemicals!

Figure 10.1: The OLC trench is filled with limestone and leads to the precipitation pond (left). SFU chemistry students collected water samples for trace metal analysis (right).

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In cooperation with the SFU Environmental Engineering Department, a research project was initiated to study the metal content from several AMD sites [19]. Chemistry and environmental engineering undergraduates cooperated in setting up the research site at approved locations. Engineering majors built a weir, measured flow rates, pH, and conductivity, while the chemistry majors collected water samples throughout the OLC and measured the trace metal content for Fe, Al, Mn, Ca, and Mg (Figure 10.1). The unexpected removal of aluminum from low pH water leads to further research into aluminum AMD systems. As we observed that aluminum was precipitating out of solution at lower than expected pH, we decided to explore if Al3+ could be removed through a combination of classic coordination chemistry with graphenic materials [20]. The functional graphenic material (FGM) was modified with functional groups that chelate the metal ions such as Al3+. The advantage is that the robust FGMs can be removed from the water system and the metal ions can be removed in the lab and recycled/reused, turning a waste product/pollutant into a potentially usable material.

10.3 Teaching As green chemistry principles have been discussed and applied throughout various sectors, there has been much debate on the best ways to integrate green chemistry into undergraduate education. Existing courses have been modified [21, 22], new courses have been developed [23–25], and games to integrate it into the classroom have been published [26]. While no consensus has been drawn as to the best method, integrating green chemistry principles into the undergraduate classroom has also brought various UN SDGs into the discussions as well. Exposing students to both green chemistry principles and SDGs, simultaneously, gives them a more comprehensive understanding of sustainability.

10.3.1 SDG 4 – quality education In addition to ensuring that quality education is inclusive and equitable, SDG 4 promotes lifelong learning. Chemistry education can exemplify this goal, as it requires students to internalize and apply their knowledge in a variety of contexts. Rather than rote memorization, students must think critically about problems to analyze the situation, determine a solution, and apply the appropriate methods to solve them. From their first chemistry class and lab experience, creative thinking is required and teamwork, particularly in the form of lab partners, is encouraged. As students progress through their chemistry education, their problem-solving skills

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become more evolved and they are given increasing responsibility in experimental design and implementation. Herein lies perhaps the most critical argument for the integration of green chemistry principles throughout a student’s education – as they grow into mature scientists who enter graduate school and the workforce, they are more likely to continue the use of green chemistry if they have observed both its importance and successful implementation. Waste prevention, safer solvents and auxiliaries, design for energy efficiency, and inherently safer chemistry for accident prevention are just four of the green chemistry principles that can seamlessly be integrated into existing or new curriculum for the benefit of both students and the environment. By prompting young chemists to consider these principles every time they complete or design an experiment, the thought processes behind the application of green chemistry principles become routine. Moreover, necessitating the use of these principles can require creative solutions, thereby enhancing the students’ problems-solving abilities and instilling the value of lifelong learning.

10.3.2 SDG 12 – responsible production and consumption In teaching labs with dozens or even hundreds of undergraduates completing the same lab assignment, significant quantities of waste can be generated in even the simplest experiments, resulting in high disposal costs and safe storage concerns. To mitigate these factors, undergraduate experiments at SFU are often proactively designed to incorporate the green chemistry principle of waste prevention, arguably the most important of the 12 principles [2]. While the global population continues to use resources unsustainably [1], designing student experiments with both green chemistry principles and SDGs in mind can help reduce a small portion of the 29.1 million tons of hazardous waste that is generated annually in the USA [27]. At SFU, chemistry majors are required to enroll in a seminar course each year that brings in speakers, encourages them to read scientific literature, and fosters discussion of scientific and ethical topics. The focus of our seminar courses for the last few years has been green chemistry. Students are required to give a final presentation, along with the submission of a written paper, that outlines a green chemistry topic. They analyze solvent choices, energy concerns, and chemical syntheses through the lens of green chemistry principles. Moreover, throughout the semester, all literature papers and external presentations are discussed with green chemistry in mind, thinking about changes to experimental procedures that could be implemented to make the work more environmentally friendly. The seminar and its green chemistry focus require students to think critically about problematic components to existing experiments, protocols, and syntheses to creatively devise alternatives to enhance the green aspects of the chemistry.

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At SFU, we have also incorporated green chemistry into the teaching labs. For example, nanoparticles (NPs) have been proposed for a wide variety of applications, from catalysis to environmental remediation [28, 29], and students need to be exposed to these materials. However, many NP syntheses require harmful solvents, harsh reducing agents, or high temperatures [30]. In an experiment for quantitative analysis lab, students compare a traditional NP synthesis with a green alternative, which can be completed with green tea as a reducing agent and is conducted on the benchtop with ambient conditions [31]. Students use UV–vis spectroscopy, dynamic light scattering measurements, and visual observations to compare the two NP products in terms of particle shape, size, polydispersity, and surface charge. This hands-on experiment allows for direct comparison of the two synthetic methods, requiring the students to analyze the solvents, energy concerns, and other experimental conditions while considering the green chemistry principles. Through both our seminar course and experimental lab assignments, we highlight for students the benefits of green synthetic methods, leading to more responsible production of chemical products by our students both at SFU and in their future careers.

10.3.3 SDG 17 – partnerships for goals In the course of a student’s chemistry education, the importance of teamwork and collaboration is emphasized in different ways, from lab partners working together on a general chemistry experiment to virtual meetings with research collaborators in a lab across the country. Students observe the benefits of this teamwork and seek out opportunities to work with other students, collaborate with their professors, or share their knowledge with the wider community. By partnering with community and national organizations, students can gain experience with both chemistry and general outreach and advance SDG 17, which stresses the importance of strengthening and maintaining partnerships for the advancement of sustainability. As previously mentioned (vide supra), chemistry majors must attend a seminar course that incorporates external speakers to broaden their knowledge of green chemistry and to emphasize the importance of a global chemical perspective. One of the speakers who was invited to speak in the seminar represented Beyond Benign, an organization focused on developing and disseminating green chemistry information to empower the practice of sustainability through chemistry. Beginning with an introduction focused on the basics of green chemistry, the speaker addressed a variety of topics ranging from risks and hazards to green chemistry solutions to common lab problems. With a previously assigned paper on designing materials for a greener product, the students discussed these topics in the seminar. They subsequently wrote reflections on the new information that they learned from the paper and speaker and how that information changed the way that they will approach experimental design. By partnering with Beyond Benign, students had

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the opportunity to learn from a leader in the green chemistry field to advance toward the goal of a more sustainable approach to chemical synthesis and experimental design. Beyond partnerships with large organizations, students are also shown the value of working with local schools and community organizations. At SFU, many of our chemistry majors participate in our Rural Outreach Chemistry for Kids (R.O.C.K.) organization, a volunteer program that works with local elementary, middle, and high school students to show them that chemistry can be both fun and interesting. SFU students work with younger children to complete hands-on experiments and activities using household products and to understand the role of chemistry in our daily lives (Figure 10.2). These classroom visits have myriad benefits for the participating students including an enhancement in their presentation, speaking, and leadership skills. Another way to incentivize students to participate in outreach activities is through specific courses. For example, in general chemistry, students have the opportunity to drop their lowest quiz score if they work with R.O.C.K. on an outreach activity. By incorporating outreach into the educational development of chemistry majors, they realize the value of sharing their knowledge and participating in both the local and global communities.

Figure 10.2: R.O.C.K. Volunteer Lucy Wagner with R.O.C.K. Leader Grace McKernan presenting polymer chemistry at All Saint’s Catholic School, Cresson, PA.

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10.4 Conclusion The UN SDGs provide many opportunities in research and teaching if embraced by chemical educators. Instead of viewing the SDGs as “new” concepts to internalize, we have shown that the SDGs can be used to restructure existing laboratories, provide opportunities to re-examine curriculum, and open new doors with research. Faculty at SFU embraced the university goals, green chemistry principles, and SDGs to craft a unique research program, emphasizing sustainability while preparing future chemists (and citizens) to apply their knowledge in an ethical manner. Concurrent with the sustainable research, even more students benefited as the teaching laboratories were modified to introduce sustainability in an intentional way. We want the students to know that we encourage and support the UN SDGs, both at SFU and in the greater scientific community!

References [1]

Independent Group of Scientists appointed by the Secretary-General Global Sustainable Development Report 2019: The Future Is Now – Science for Achieving Sustainable Development; United Nations Publications, New York, 2019. [2] Anastas, P. T.; Warner, J. C. Green Chemistry: Theory and Practice; Oxford University Press: New York, 1998. [3] Abdussalam-Mohammed, W.; Ali, A. Q.; Errayes, A. O. Green Chemistry: Principles, Applications, and Disadvantages. Chem. Method. 2020, 4, 408–423. [4] Krebs, J.; McKeague, M. Green Toxicology: Connecting Green Chemistry and Modern Toxicology. Chem. Res. Toxicol. 2020, 33, 2919–2931. [5] Benvenuto, M. A. ed. Green Chemical Processes: Developments in Research and Education; Walter de Gruyter GmbH: Berlin/Boston, 2017. Accessed May 27, 2021. ProQuest Ebook Central. [6] Zimmerman, J. B.; Anastas, P. T.; Erythropel, H. C.; Leitner, W. Designing for a Green Chemistry Future. Science. 2020, 367, 397–400. [7] Hurst, G.; Systems Thinking Approaches for International Green Chemistry Education. Green Sustainable Chem. 2020, 21, 93–97. [8] Andraos, J.; Dicks, A. P. Green Chemistry Teaching in Higher Education: A Review of Effective Practices. Chem. Educ. Res. Pract. 2012, 13, 69–79. [9] Leadbeater, N.; McGowan, C. Clean Fast Organic Chemistry: Microwave Assisted Laboratory Experiments; CEM Publishing: Matthews, NC, 2006. [10] Zhu, Y.-J.; Chen, F. Microwave-Assisted Preparation of Inorganic Nanostructures in Liquid Phase. Chem. Rev. 2014, 114, 6462–6555. [11] Stock, A.; Zovinka, E. P. Microwaves: Green Machines for Green Chemistry? J. Chem. Ed. 2010, 87, 350–352. [12] Arnold, A. M.; Kwak, D. J.; Löfgren, L. E.; Walters, B. M.; Wilt, A. L.; Woldemeskel, S. A.; Zovinka, E. P. Microwaving Metals: Inserting Metals into Porphyrin Ligands Using Microwave Methods. Chem. Educ. 2014, 19, 296–298. [13] Shy, H.; Mackin, P.; Orvieto, A. S.; Gharbharan, D.; Peterson, G. R.; Bampos, N.; Hamilton, T. D. The Two-Step Mechanochemical Synthesis of Porphyrins. Faraday Discuss. 2014, 170, 59–70.

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[14] Do, J.-L.; Friscic, T. Mechanochemistry: A Force of Synthesis. ACS Cent. Sci. 2013, 3, 13–19. [15] Atoyebi, A. O.; Brückner, C. Observations on the Mechanochemical Insertion of Zinc(II), Copper(II), Magnesium(II), and Select Other Metal(II) Ions into Porphyrins. Inorg. Chem. 2019, 58, 9631–9642. [16] Clark, R. A.; Stock, A. E.; Zovinka, E. P. Metalloporphyrins as Oxidation Catalysts: Moving toward “Greener” Chemistry in the Inorganic Chemistry Laboratory. J. Chem. Educ. 2012, 89, 271–275. [17] Clark, R. A.; Stock, A. E.; Zovinka, E. P. Metalloporphyrins as Oxidation Catalysts of Organic Substrates. In: Afonso, C. Ed., Comprehensive Organic Chemistry Experiments for the Laboratory Classroom (COCELC); Royal Society of Chemistry: Cambridge, 2016, 758–761. [18] Skousen, J.; Zipper, C. E.; Rose, A.; Ziemkiewicz, P. F.; Nairn, R.; McDonald, L. M.; Kleinmann, R. L. Review of Passive Systems for Acid Mine Drainage Treatment. Mine Water Environ. 2017, 36, 133–153. [19] Spellman, C. Jr.; Carvajal, S.; Weyant, C. J.; Krug, J. P.; Krupa, R. C.; Wolfe, D.; Li, Y.; Zovinka, E. P.; Rose, A.; Strosnider, W. Research, Teaching and Service with Open Limestone Channels and Undergraduates in the Allegheny Highlands. Reclam. Matters. 2015, Spring, 28–31. [20] Karpinsky, M. M.; Arnold, A. M.; Lee, J.; Jasper, G.; Bockstaller, M. R.; Sydlik, S. A.; Zovinka, E. P. Acid Mine Drainage Remediation: Aluminum Chelation Using Functional Graphenic Materials. ACS Appl. Mater Interfaces. 2020, 12, 32642–32648. [21] Edgar, L. J. G.; Koroluk, K. J.; Golmakani, M.; Dicks, A. P. Green Chemistry Decision-Making in an Upper-level Undergraduate Organic Laboratory. J. Chem. Educ. 2014, 91, 1040–1043. [22] Timmer, B. J. J.; Schaufelberger, F.; Hammarberg, D.; Franzen, J.; Ramstrom, O.; Diner, P. Simple and Effective Integration of Green Chemistry and Sustainability Education into an Existing Organic Chemistry Course. J. Chem. Educ. 2018, 95, 1301–1306. [23] Kennedy, S. A. Design of a Dynamic Undergraduate Green Chemistry Course. J. Chem. Educ. 2016, 93, 645–649. [24] Gross, E. M. Green Chemistry and Sustainability: An Undergraduate Course for Science and Nonscience Majors. J. Chem. Educ. 2012, 90, 429–431. [25] Haley, R. A.; Ringo, J. M.; Hopgood, H.; Denlinger, K. L.; Das, A.; Waddell, D. C. Graduate Student Designed and Delivered: An Upper-Level Online Course for Undergraduates in Green Chemistry and Sustainability. J. Chem. Educ. 2018, 95, 560–569. [26] Mellor, K. E.; Coish, P.; Brooks, B. W.; Gallagher, E. P.; Mills, M.; Kavanagh, T. J.; Simcox, N.; Lasker, G. A.; Botta, D.; Voutchkova-Kostal, A.; Kostal, J.; Mullins, M. L.; Nesmith, S. M.; Corrales, J.; Kristofco, L.; Saari, G.; Steele, W. B.; Melnikov, F.; Zimmerman, J. B.; Anastas, P. T. The Safer Chemical Design Game: Gamification of Green Chemistry and Safer Chemical Design Concepts for High School and Undergraduate Students. Green Chem. Lett. Rev. 2018, 11, 103–110. [27] United States Environmental Protection Agency. EPA’s Report on the Environment – Hazardous Waste, last revised August 2020. https://cfpub.epa.gov/roe/indicator.cfm?i=54 (accessed 2021-05-25). [28] Astruc, D. Introduction: Nanoparticles in Catalysis. Chem. Rev. 2020, 120, 461–463. [29] De, M.; Ghosh, P. G.; Rotello, V. M. Applications of Nanoparticles in Biology. Adv. Mater. 2008, 20, 4225–4241. [30] Duan, H.; Wang, D.; Li, Y. Green Chemistry for Nanoparticle Synthesis. Chem. Soc. Rev. 2015, 44, 5778–5792. [31] Sharma, R. K.; Gulai, S.; Mehta, S. Preparation of Gold Nanoparticles Using Tea: A Green Chemistry Experiment. J. Chem. Educ. 2012, 89, 1316–1318.

Index acetylcholinesterase 55 agrochemicals 159 airborne dusts 59 algae 115 American Association for the Advancement of Science 48 American Chemical Society 48, 67 American Chemical Society’s Green Chemistry Institute 81 American Physical Society 48 bio-based solvents 96 bio-based sources 110 biorefineries 110, 163 biosensors 55 Brundtland report 164 carbon capture technologies 112 carbon dioxide 69 carbon nanotube 64 carbon nanotubes 60 carbon-free energy 72 chemotherapy 56 chlorohydrocarbons 100 climate change 176 Climate Clock 175 conducting polymers 50 Council on Undergraduate Research 25

flooding patterns 144 fluorous solvents 95 forest fires 59 fossil fuel 4 genocide 73 Geological Society of America 48 geothermal fluid 63 global equity 130 gold nanoparticles 63 gram-negative 14 gram-positive 14 green chemistry principles 22 Grignard reagent 71 hydrodistillation 9 independent research project 27 International Council for Science 47 International Social Science Council 47 interstellar dust 59 ionic liquids 95 levoglucosenone 96 life cycle thinking 4, 22 lignocellulosic biomass 110 Li-ion batteries 106 lithium-ion battery 64 lithium-ion battery technology 65 lithium–silicon anodes 65

deep eutectic solvents 95 deforestation 140 desalination of water 50 dihydrolevoglucosenone 96 dimethyl sulfoxide 96 dimethylformamide 96 drug delivery 56 dust storms 59

metalloenzymes 194 metalloporphyrins 193 metal-oxide–semiconductor field-effect transistor 67 minimum explosive concentration 60 Moore’s law 67

electronics 159 Environmental Protection Agency 4 Environmental Social Governance 165 environmental stewardship 36 environmental wellness 135 essential oils 29

nanofertilizers 54 nanoimprint lithography 50 nanomaterial solar cells 50 nanoparticles 199 National Nanotechnology Initiative (NNI) 58 NSTA 48

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ocean 73 Office of Energy Efficiency and Renewable Energy 68 ozone layer 135 pandemics 73 perfluorocarbons 100 pharmaceuticals 159 photocatalytic degradation 150 phytochemistry 163 plastics 159 poly(methyl methacrylate) 66 polyoxometalate IL 102

SNAr reaction 18 solar photovoltaic power storage system 63 supercritical fluids 95 sustainability 73 sustainability and the chemistry enterprise 82 switchable solvents 95 systems thinking 4 tetrachloroethane 100 tie-dyeing 23 Toxic Substances Control Act 59 UN millennium development goals 130

quantum dot semiconductors 62

volcanic activity 59

rain forests 73 Report of the World Commission on Environment and Development 135

waste plastics 107 wastewater treatment 50 water purification 60 wind erosion 59 wind turbines 64

safer solvents 68, 194 scientific inquiry 35 SDG index 73 smart delivery systems 53

youth activism 176

De Gruyter series in green chemical processing Volume 1 Mark Anthony Benvenuto (Ed.) Sustainable Green Chemistry, 2017 ISBN 978-3-11-044189-5, e-ISBN 978-3-11-043585-6 Volume 2 Mark Anthony Benvenuto (Ed.) Green Chemical Processes: Developments in Research and Education, 2017 ISBN 978-3-11-044487-2, e-ISBN 978-3-11-044592-3 Volume 3 Mark Anthony Benvenuto, Heinz Plaumann (Eds.) Green Chemistry in Industry, 2018 ISBN 978-3-11-056113-5, e-ISBN 978-3-11-056278-1 Volume 4 Mark Anthony Benvenuto, Larry Kolopajlo (Eds.) Green Chemistry Education: Recent Developments, 2018 ISBN 978-3-11-056578-2, e-ISBN 978-3-11-056649-9 Volume 5 Mark Anthony Benvenuto, Heinz Plaumann (Eds.) Green Chemistry in Government and Industry, 2020 ISBN 978-3-11-059728-8, e-ISBN 978-3-11-059778-3 Volume 6 Mark Anthony Benvenuto, George Ruger (Eds.) Green Chemistry and Technology, 2021 ISBN 978-3-11-066991-6, e-ISBN 978-3-11-066998-5 Volume 7 Mark Anthony Benvenuto, Heinz Plaumann (Eds.) Green Chemistry: Water and its Treatment, 2021 ISBN 978-3-11-059730-1, e-ISBN 978-3-11-059782-0 Volume 8 Mark Anthony Benvenuto, Heinz Plaumann (Eds.) Green Chemistry: Advances in Alternative Energy, 2022 ISBN 978-3-11-070638-3, e-ISBN 978-3-11-070663-5

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De Gruyter series in green chemical processing

Volume 9 Mark Anthony Benvenuto, Steven Kosmas (Eds.) Green Chemistry and UN Sustainability Development Goals, 2022 ISBN 978-3-11-072386-1, e-ISBN 978-3-11-072396-0 Volume 10 Mark Anthony Benvenuto, Lindsey Welch (Eds.) Green Chemistry: Research and Connections to Climate Change, Planned 2023 ISBN 978-3-11-074560-3, e-ISBN 978-3-11-074565-8