Green Chemistry: Process Technology and Sustainable Development [1st ed. 2021] 9811637458, 9789811637452

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Tatsiana Savitskaya Iryna Kimlenka Yin Lu et al.

Green Chemistry Process Technology and Sustainable Development

Green Chemistry

Tatsiana Savitskaya · Iryna Kimlenka · Yin Lu · Dzmitry Hrynshpan · Valentin Sarkisov · Jie Yu · Nabo Sun · Shilei Wang · Wei Ke · Li Wang

Green Chemistry Process Technology and Sustainable Development

Tatsiana Savitskaya Belarusian State University Minsk, Belarus

Iryna Kimlenka Belarusian State University Minsk, Belarus

Yin Lu Zhejiang Shuren University Hangzhou, China

Dzmitry Hrynshpan Belarusian State University Minsk, Belarus

Valentin Sarkisov Belarusian State University Minsk, Belarus

Jie Yu Zhejiang Shuren University Hangzhou, China

Nabo Sun Zhejiang Shuren University Hangzhou, China

Shilei Wang Zhejiang Shuren University Hangzhou, China

Wei Ke Zhejiang Shuren University Hangzhou, China

Li Wang Zhejiang Shuren University Hangzhou, China

ISBN 978-981-16-3745-2 ISBN 978-981-16-3746-9 (eBook) https://doi.org/10.1007/978-981-16-3746-9 Jointly published with Zhejiang University Press The print edition is not for sale in China (Mainland). Customers from China (Mainland) please order the print book from: Zhejiang University Press. ISBN of the Co-Publisher’s edition: 978-7-308-21580-0 © Zhejiang University Press 2021 This work is subject to copyright. All rights are reserved by the Publishers, whether the whole or part of the material is concerned, specifically the rights of reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. The publishers, the authors, and the editors are safe to assume that the advice and information in this book are believed to be true and accurate at the date of publication. Neither the publishers nor the authors or the editors give a warranty, express or implied, with respect to the material contained herein or for any errors or omissions that may have been made. The publishers remain neutral with regard to jurisdictional claims in published maps and institutional affiliations. This Springer imprint is published by the registered company Springer Nature Singapore Pte Ltd. The registered company address is: 152 Beach Road, #21-01/04 Gateway East, Singapore 189721, Singapore

Preface

Green chemistry and technology is a new interdisciplinary subject with significant social needs and clear scientific objectives, which emerged in the 1990s. It is the forefront and important field of international chemical and chemical research. The development of traditional chemistry to green chemistry has become the inevitable trend of chemical industry from “extensive” to “intensive”. It is the only way for China’s environmental protection to adopt the environmental protection concept of treating both symptoms and root causes. Under the guidance of one belt, one road to respond to the call of the national “13th Five-Year plan”, “Green is the necessary condition for sustainable development”, Zhejiang Shuren University and Belarus National University signed a memorandum of cooperation in education and research, and set up the “Belarus research center” and awarded the Ministry of education’s national and regional research center. The two sides jointly discussed how to protect the ecological environment and realize the construction of an ecological country while vigorously applying green chemical technology to promote the economic development of the two countries. In order to publicize the concept of green chemistry and sustainable development, and let environmental education actively penetrate into chemical education, scholars from both sides jointly compiled “Green Chemistry—Process Technology and Sustainable Development”. Based on the principle of green chemistry, this paper reviews the progress of green chemistry at home and abroad, and systematically introduces the advanced, practical, and prospective green chemistry technology and its sustainable development in modern chemical industry. It comprehensively discusses the major sources of practice, principle, sustainable development, and the methodology of ecological chemistry. The development of green chemistry in Belarus and China is introduced, which fully embodies the connotation and extension of green chemistry, and shows the brilliant prospects of green chemistry. The book consists of seven chapters. Chapters 1 and 2 is the background of green chemistry, which mainly introduces principles and aims of green chemistry. Chapter 3 mainly introduces the applications of green chemistry, including the concept of green chemical synthesis, green chemistry in catalysis, and green solvents. Chapter 4 is about green activation methods. Chapter 5 v

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introduces sustainable development concept and green management of chemicals. Chapter 6 introduces renewable raw materials and energy, expounds the advantages of biomass as green chemical synthesis raw materials, and introduces the relevant commercial products. Chapter 7 takes the development status of green chemistry in Belarus and China as an example, and advocates the education mode that integrates the truth of green chemistry science with the rationality of human needs. This book is comprehensive in content, illustrated, and highly targeted. It has been designed as a series of lectures delivered for Belarusian and Chinese students.It is suitable for teachers, students, and researchers engaged in the research of chemistry, chemical engineering, and environment. This book shows readers a continuous development of a complete green chemical system, so that more scholars and the public have a relatively clear understanding of green chemistry and chemical industry, so as to promote the healthy development of green chemistry.

Minsk, Belarus Minsk, Belarus Hangzhou, China Minsk, Belarus Minsk, Belarus Hangzhou, China Hangzhou, China Hangzhou, China Hangzhou, China Hangzhou, China November 2020

Authors of Green Chemistry Tatsiana Savitskaya Iryna Kimlenka Yin Lu Dzmitry Hrynshpan Valentin Sarkisov Jie Yu Nabo Sun Shilei Wang Wei Ke Li Wang

Contents

1 Principle of Green Chemistry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.1 Green Economy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.2 The Sustainable Development Concept . . . . . . . . . . . . . . . . . . . . . . . . 1.3 Cleaner Production Strategy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.4 Green Chemistry: Principles, Current State, and Development Trends . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.5 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1 1 2 4 5 13 14

2 Aims of Green Chemistry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1 Global Product Strategy (GPS) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2 Responsible Care (RC) Initiative . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.3 REACH Regulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4 Globally Harmonized System of Classification and Labeling of Chemicals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

15 15 16 18

3 Applications of Green Chemistry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.1 Green Chemical Synthesis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.1.1 Chemical Reaction Efficiency . . . . . . . . . . . . . . . . . . . . . . . . . . 3.1.2 E-Factor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.1.3 The Strategy of Organic Synthesis . . . . . . . . . . . . . . . . . . . . . . 3.1.4 General Recommendations . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.2 Green Catalysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.2.1 Catalysis and Catalyst . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.2.2 Homogeneous Green Catalysis . . . . . . . . . . . . . . . . . . . . . . . . . 3.2.3 Heterogeneous Catalysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.2.4 Biocatalysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

31 31 31 36 38 41 43 43 47 50 51

27 30

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3.3 Green Solvents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.3.1 Chemical Reactions Under Solvent-Free Conditions . . . . . . 3.3.2 Dimethylcarbonate: Green Solvent and Ambident Reagent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.3.3 Reactions at Supercritical Conditions . . . . . . . . . . . . . . . . . . . 3.3.4 Ionic Liquids . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.3.5 Fluorinated Biphasic Solvents . . . . . . . . . . . . . . . . . . . . . . . . . 3.4 Green Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.4.1 Twelve Principles of Green Engineering . . . . . . . . . . . . . . . . . 3.4.2 Transfer from Green Reaction to Green Industrial Technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.4.3 Process Safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.4.4 Inherently Safer Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.4.5 Process Intensification as Green Design Concept . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

55 55 58 61 66 73 75 75 76 79 83 86 91

4 Green Chemistry Technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93 4.1 Ultrasound Activation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93 4.2 Microwave Activation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98 4.3 Photochemical Activation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101 4.4 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105 5 Green Chemistry and Sustainable Development . . . . . . . . . . . . . . . . . . . 5.1 Sustainable Development (SD) Strategy Genesis and Evolution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.2 National SD Strategy in Belarus and in China . . . . . . . . . . . . . . . . . . . 5.3 Development of Ecological Policy and Natural Resource Economics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.4 Ecological Management System (EMS) . . . . . . . . . . . . . . . . . . . . . . . . 5.5 Ecolabel System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.6 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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113 116 119 122 123

6 Renewable Sources of Raw Material and Energy . . . . . . . . . . . . . . . . . . 6.1 Renewable Energy Sources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.2 Biomass as a Source of Raw Materials for Chemical Synthesis . . . . 6.3 Basic Chemical Products of Biomass Conversion . . . . . . . . . . . . . . . 6.4 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

125 125 126 130 133 133

7 Green Chemistry in China and Belarus . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.1 National Strategy of Green Economy Development in Belarus . . . . 7.2 Green Chemistry as an Educational Platform for Green Economy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.2.1 Benefits of Green Chemistry . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.2.2 Some Examples of Green Chemistry in Belarus . . . . . . . . . .

135 135

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Contents

7.3 Achievements in Green Chemistry Research and Technologies in China . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.3.1 Background and Premise of Green Chemistry in China . . . . 7.3.2 Current Situation of Green Chemistry in China . . . . . . . . . . . 7.3.3 Strategies and Outlook of Green Chemistry in China . . . . . . 7.4 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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142 142 144 145 148 149

Chapter 1

Principle of Green Chemistry

Abstract The need of ecological civilization gives a thorough exploration of resources and ecological environment in the world. The author makes an active attempt to seek available ways to keep the sustainable development of green economy, resources, environment, and green chemistry to change the pattern of rising and sustainable development of the economy. To develop the green industry means industrial ecologicalization. To depend on the law and economic means to strengthen national consciousness of environmental protection. Keywords Sustainable development · Cleaner production · Green chemistry

1.1 Green Economy Green has always symbolized life, hope, and recently has come to mean welfare and prosperity as well. That’s why ecological civilization is considered a result of sustainable development. The term sustainable development has become firmly entrenched in the professional vocabulary in economic, social, ecological, and other spheres. A conceptual definition of this term, although interpreted by linguists as continuous steady growth, implies the further development, which does not contravene the continued existence of mankind and its development in the same direction. Economists, such as Daniel Bell, have suggested a new term to describe the current stage of development of society—a so-called post-industrial society or knowledge society [1]. Its sustainable development is based on the knowledge economy. This relatively new term means that the economy encompasses not only technologies but also the whole process of knowledge production. The knowledge triangle, which embodies a key driver of a knowledge-based economy, refers to the interaction between research, education, and innovation. The use of scientific knowledge and technological ideas does not lead to their depletion, but rather facilitates the accumulation of intellectual potential of a nation. Knowledge, unlike gas and oil, may be considered a renewable resource. Knowledge economy has also been proclaimed as a top priority of Belarusian economic development in the coming years. President Alexander Lukashenko noted that “there’s only one way namely © Zhejiang University Press 2021 T. Savitskaya et al., Green Chemistry, https://doi.org/10.1007/978-981-16-3746-9_1

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an expedited transition to innovative, knowledge-based, resource-saving, globally competitive economy.” [2]. Economic growth and environmental protection complement each other on the path toward sustainable development. In this connection, the term green economy has been coined. President of the People’s Republic of China Xi Jinping has pointed out that “green is gold” and that moving toward a new era of Ecocivilization and building a “Beautiful China” are key to realizing the “Chinese Dream” of rejuvenating the nation [3]. The Green Economy Initiative, supported by more than 20 states, was put forward by the United Nations Environment Programme (UNEP) in 2008 [4]. It defined a green economy as low carbon, resource efficient, and socially inclusive. This economy also enhances social welfare, ensures social equality, while mitigating environmental risks and diminishing the prospects of environmental degradation. Three years after Irina Bokova, UNESCO Director-General, looking back on 2011 and setting some priorities for 2012, emphasized that it’s necessary to build up not only green economy but also green society [5]. Even though little time has passed, there’s no doubt the green strategy affected all spheres of life and our world is well on the way toward the new ecological civilization. This way in its turn more and more seldom resembles attempts of NGOs to combat environmental pollution and pollutants. For instance, at the United Nations Conference on Sustainable Development—Rio + 20—held in Rio de Janeiro, Brazil, on June 20–22, 2012, member states spotlighted the exigencies of technological innovation and also laid down some particular criteria for green technologies. On September 25, 2015, the 193 countries of the UN General Assembly adopted the 2030 Development Agenda titled Transforming our world: the 2030 Agenda for Sustainable Development which renewed hope for a bold transition toward a low-carbon economy, greater efficiency of natural resources, inclusive green economic growth, and overall sustainable development. To take the next step—moving from commitment to action—countries must have an integrated approach to implementation that harmonizes environmental integrity, social inclusiveness, and economic prosperity. For instance, the National Communication (2012) specified the main trends and principles of Belarus’s transition toward a green economy, as an essential tool for ensuring sustainable development and environmental security. According to the Country Report “China’s Path to Green Economy” (2015), the current period can be considered as the “great leap-forward” of China’s green economy agenda both conceptually and implementation-wise.

1.2 The Sustainable Development Concept In recent years, green development trends ceased being the subject of popular publications only and shifted toward actual use. For example, green building, as a special system for construction solutions assessment, in many countries is already regulated by the set of national standards. The development of this system is primarily stimulated by those who engage in investment and further facility operation, those who

1.2 The Sustainable Development Concept

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wish to have a comprehensive assessment of the expediency of the made decision, of the convenience of buildings in the process of operation, of their impact on the environment and the economy. For instance, if the construction takes place in an area, which has some clean water issues, any solution enabling to save water will be rated higher. The European Union even adopted Directive 2010/31/EU of 19 May 2010 on the energy performance of buildings. Under this Directive, Member States must ensure that by December 31, 2020 all new buildings shall be nearly zero-energy consumption buildings. Much attention is paid to the reuse of materials. An example of the use of a green building is Sochi Olympic facilities. The consumption, output expansion, and active advertising of green goods accounted for the fact that an estimated 95% of the European respondents are ready to purchase green goods, 75% of them are aware of this type of goods, and 63% try to find them on store shelves. Public polls revealed the dependence of green goods consumption level on the level of education. Meanwhile, modern education in different regions around the world is gradually turning toward greenness. Bypassing various types of labor activities, it becomes apparent that content, approaches, and methods of green economy education coincide with that of sustainable development education. Sometimes green economy education is interpreted in a more narrow sense, defining it as a type of education focused on changing the employment structure. It’s also targeted at increasing demand for professionals in environmental technology, goods and services, and training of specialists of new professions, so-called green collars, along with the specific specialists, for instance, specialists in biofuel production. In fact, sustainable development education is generally expected to conduct effective training of creative individuals capable of solving uphill tasks through innovative techniques. At the same time, it’s necessary to be conscious of its interdisciplinarity and social responsibility to society. The first ones to recognize it from this perspective were chemists, who faced the public outcry, while regarded as being accounted for environmental contamination. Their consequent actions targeted toward changing the negative image resulted in that chemistry became the first natural science to be granted the green status. Perhaps, if biology developed in such a way as chemistry did, it would potentially become green. The diversity of shades of green in the higher education system is instantiated by green university and green campus conceptions, which are implemented in several countries. The United Nations Environment Programme (UNEP) has defined the goals and objectives of green universities in “Green University Toolkit” publication. Green university works toward environmental protection, namely carbon emission reduction, separate waste collection, water and electricity saving, ecological infrastructure development, and outreach campaigns. Green students participate in eco-projects and events, carry out researches and project works on environmental protection. In 2009, Grist, an American online magazine, issued the list of Top Green Colleges and Universities. The green cohort comprised educational institutions of the USA, the UK, Canada, Costa Rica, and Scotland. Such institutions as Harvard University, the London School of Economics, and the University of Copenhagen have been for years committed to the green principles of their economic and sustainable development. The Centre for Bioeconomy and Eco-innovations (CBE) at Moscow

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State University named after Lomonosov together with Tetra Pak and World Wildlife Fund has started the “Green universities for Green economy” project in Russia. The main objective of the project is to educate the new generation of professionals, who will take into account environmental factors in their activities. There is another green university ranking—UI Green Metric World University Racking—which aims to draw the attention of the academic community to the problems of ecology. In 2013, 301 universities from 61 countries tried out for this ranking. As in the academic rankings, the leading positions were occupied by universities of the UK and the USA. Among those universities, that made it to the Top-10, were the University of Nottingham (UK), University College Cork (UCC) (Ireland), Northeastern University (USA), the University of Bedford (UK), the University of Connecticut (USA), etc. However, the makeup of the Top-10 green university ranking differs from the established global academic university rankings. In the former, the assessment is carried out on the basis of criteria, such as specific eco-indicators, delineating campus attitude to the environment, the use of energy-efficient appliances, facing the waste recycling university program, etc. There’s no doubt that the assessment of greenness of laboratory practical works must be appended to the number of these indicators. The researchers conducted in American and European universities show that an estimated 90% of all emission is accounted for by university labs, with about 88% of it being toxic substances of various types. At the present moment, by all accounts, chemistry does not correlate with the concept of green science. The survey data submitted by Lomonosov Moscow State University in 2010 attest to the fact that biology is generally recognized by the public as the main green science [6]. No wonder, as in the chemical sector of the economy there is a direct correspondence between the benefit of goods and the damage, caused to the environment and human health by the manufacturing process. Many major industrial areas around the globe are now subject to significant chemical pollution. Considerable funds are spent on the establishment of wastewater treatment plants and hazardous substances disposal. Such a method of solving ecological issues at the end of the production process is called the end-of-pipe approach. Parallel to this method, another one, a so-called precautionary approach, has become increasingly prominent over the past two decades. It focuses on prevention rather than dealing with the consequences of environmental degradation. In practice, the precautionary approach encompasses the optimization of production processes, energy-saving technologies implementation, the selection of more environmentally friendly raw materials, new product design, internal and external waste recycling, reducing the use of toxic and hazardous substances.

1.3 Cleaner Production Strategy A Cleaner Production (CP) strategy, coined in 1989 by UNEP, has firmly established itself as revolutionary, as it enables chemists to produce required substances in a more environmentally friendly way, which is harmless to the environment at any

1.3 Cleaner Production Strategy

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stage of the manufacturing and is safe for those who engaged in this process. In fact, Cleaner Production represents a systematic approach to environmental protection, dealing with all the phases of manufacturing, as well as disposal process, i.e., the entire lifecycle “from cradle to grave,” aimed at prevention or decreasing short and long-run risks, threatening human health and the environment. In addition to “Cradle to Grave” mentality, “Cradle to Cradle” concept has been recently introduced as an innovative way of creating products. William McDonough, co-author of the book “Cradle to Cradle: Remaking the Way We Make Things,” said “Cradle to cradle is a strategy of hope; it’s about sharing the resources and the planet we have. It’s about rethinking our role in our planet and on the environment.” [7]. Cleaner Production strategy has led to the emergence of a brand new branch of chemistry, termed green chemistry, which can be regarded as one of the Cleaner Production methods.

1.4 Green Chemistry: Principles, Current State, and Development Trends Green chemistry in the 21st century is not just a fashionable trend, it is an urgent need. Green chemistry is an essential tool for achieving sustainable development goals. In 2017, within the IUPAC the Interdivisional Committee on Green Chemistry for Sustainable Development was created. In Fig. 1.1 the phrase “Green Chemistry” is written using symbols of chemical elements. It was molded in the USA, then outspread to Europe, seeped into Russia, and has reached Belarus and China. It’s also been recently given prominence in the developing countries. For instance, the Green Chemistry Congress held in Addis Ababa (Ethiopia) in November 2010 featuring Prof. Paul T. Anastas, co-founder of green chemistry, resulted in launching the Pan Africa Chemistry Network.

Fig. 1.1 “Green chemistry” written by the symbols of the chemical elements of the Periodic Table

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The main historical milestones in green chemistry development are the following: 1962—Rachel Carson, writer, biologist, and environmental conservation icon, published the first of three installments of “Silent Spring”. The publication helped spread public awareness of the hazards of environmental pollution and pesticides to the environment. 1969—President Richard Nixon established the Citizen’s Advisory Committee on Environmental Quality and a Cabinet-level Environmental Quality Council (http://www.presidency.ucsb.edu/). Later that year, Nixon expanded his environmental efforts by appointing the White House Committee to determine whether an environmental agency should be developed. 1970—The Environmental Protection Agency (EPA) was launched. 1980s/1988—Shift from end-of-pipeline control to pollution prevention was recognized, leading to the Office of Pollution Prevention and Toxics in 1988. In the same years, safe chemistry activities were performed in Great Britain, Japan, France, yet they were not regulated at the state level, as in the United States. 1990—The Pollution Prevention Act under the George H. W. Bush Administration was passed. 1993—The EPA implemented the Green Chemistry Program, which served as a precedent for the design and processing of chemicals that lessen the negative environmental impact. 1995/1996—In 1995, President Bill Clinton established the Presidential Green Chemical Challenge Awards, which served to encourage those involved with the manufacture and processes of chemicals to incorporate environmentally sustainable design and processes in their practices. The following year, the first recipient received the award, the only award issued by the president that honors work in chemistry. Source: http://portal.acs.org/. 1997—The Green Chemistry Institute was launched. It was created to advance the broader chemistry enterprise and its practitioners for the benefit of Earth and its people. Source: http://portal.acs.org/. 1998—“Twelve Principles of Green Chemistry” was published by Paul Anastas and John Warner. Within the same year, Green Chemistry Network was formed by the Royal Society of Chemistry, backed by the Department of Chemistry, University of York. 2000s–Present—Some major green chemistry achievements include the California Green Chemistry Initiative. In 2006, the first International IUPAC Conference on Green Chemistry as a Chemistry for Sustainable Development was held in Dresden, 2 years later the second one takes place in St. Petersburg. In 2008, Governor Arnold Schwarzenegger signed the bills, which served to develop policy options for green chemistry (http://www.dtsc.ca.gov). One year later, President Obama nominated Paul Anastas as head of Research and Development at the EPA. The concept was first introduced by Paul Anastas and John Warner in 1998 [8]. Today, any type of advancement in chemistry contributing to the improvement of environmental conditions is called green chemistry. Paul Anastas once noted that the best chemists go in for green chemistry, and that green chemistry is just a part of

1.4 Green Chemistry: Principles, Current State, …

7

doing good chemistry. Green chemistry has also prompted the change in the equation: “Risk = Hazard * Dose (Exposure),” by excluding the hazard component for its impact time. In other words, it has reduced the risk by making reactants and processes less dangerous. It all boils down to the formal definition of green chemistry “as a philosophy of chemical synthesis that minimize the use and generation of hazardous substances.” The notion, however, is not quite accurate, if it’s treated solely as a branch of chemistry that embeds new safe manufacturing processes which help to reduce or eliminate the use of hazardous substances. Green chemistry is a revolutionary concept invented to minimize and prevent environmental contamination. Before people often used the same definitions for green and sustainable chemistry calling green chemistry is sustainable chemistry. But as once Joaquin Barroso, the Italian chemist said we need to differentiate Green Chemistry and Sustainable Chemistry or we take the risk of confusing purpose and procedure. Green Chemistry is oriented toward the way we perform chemistry in order to achieve a sustainable chemical industry. Sustainable Chemistry is the philosophical approach with which the ongoing transformations can still be performed while the damage to the environment, namely our ecosystems, is brought to a minimum in order to maintain our industry and the benefits there from for generations to come and spread to a larger scale. But this is not only a matter of environmentalist nature; it is also an economical matter. Qing-shi Zhu, a physical chemist and manufacturer of methanol automobile fuel from biomass sources, during a press conference said: “The ‘green’ in green chemistry is also the color of money.” Green chemistry requires in-depth consideration, as the basis for a systematic approach to the chemical products manufacturing. The novelty of this approach lies in the fact that a manufacturer is responsible not only for manufacturing process to be ecologically friendly, but also for the entire “life cycle” of the product, controlled at various stages. In 2010, the International Standard ISO 26000:2010 was released, providing guidelines for social responsibility including environmental issues, which can be thus named green. Green chemistry concept can be imaged by a mnemonic, PRODUCTIVELY, which captures the essence of the twelve principles of green chemistry: P—Prevent wastes; R—Renewable materials; O—Omit derivatization steps; D—Degradable chemical products; U—Use of safe synthetic methods; C—Catalytic reagents; T— Temperature, pressure ambient; I—In-process monitoring; V—Very few auxiliary substances; E—E-factor, maximize feed in product; L—low toxicity of chemical products; Y—Yes, it is safe. These 12 principles display the current situation in the USA and Europe. The influence of national features on the formulation of the green chemistry principles can be observed in the greening principles, stated at the 1st Green Chemistry Congress, held in Africa in 2010. G—generate wealth not waste; R—regard for all lives and human health; E—energy from the sun; E—ensure degradability and no hazards;

8

1 Principle of Green Chemistry

N—new ideas and different thinking; E—engineer for simplicity and practicality; R—recycle whenever possible; A—appropriate materials for function; F—fewer auxiliary substances and solvents; R—reactions using catalysts; I—indigenous renewable feedstocks; C—cleaner air and water; A—avoid the mistakes of others. Working according to green chemistry principles is clearly demanding and involves great responsibility. Sometimes, it is necessary to go off the beaten track to solve the problem. Scientists at Lomonosov Moscow State University have thus elaborated the 13th principle of green chemistry saying “working the way it is usually done will get you only so far.” Green chemistry particularly offers new quantitative parameters (metrics) to assess the degree of “greenness” of the process, such as E-factor (Environment factor), introduced by Roger Sheldon, defined as the mass ratio of waste to desired product mass, and atom efficiency, calculated by dividing the molecular weight of the product by the sum total of the molecular weights of all substances formed in the stoichiometric equation for the reaction involved. The smaller E-factor and the closer atom efficiency to 100% are the greener process or reaction is. These two parameters differ significantly, since E-factor indicates the amount of waste generated per kg of product. It takes the chemical yield into account and includes reagents, used catalysts, waste, solvents losses, and all process aids, which are not included in the stoichiometric equation used to calculate atom efficiency. It is important as the amount of waste at the end of the process can exceed the amount of production residue. The E-Factor concept has played a major role in processes of fine organic synthesis in the pharmaceutical industry (from 25 to 100), and was the least valuable for bulk chemicals synthesis (1000 tonnes in 3 years, 100– 1000 tonnes in 6 years, 1–100 tonnes in 11 years. Thus, registration comprises the stage for a term of 3, 6, and 11 years, in relation to production or import volume (Fig. 2.2). • Risk. Extremely hazardous substances will be evaluated within the first 3 years. Among these are CMR substances (carcinogenic, mutagenic, or reprotoxic substances), PBT (persistent, bioaccumulative, and toxic), vPvBs (very persistent and very bioaccumulative), etc. There are several rules for the registration of chemicals: (1)

(2)

(3)

“One substance—one registration” (OSOR). REACH encourages data sharing among all companies by the joint submission of registration data to ECHA. In rare cases, companies may be excused from submitting registration dossiers, if the potential commercial disadvantage or violation of their intellectual property rights due to information disclosure is discerned. The tonnage range from 1 to 10 tonnes p.a. An estimated 17000 chemicals manufactured or imported in small volumes (1–10 t/a) are free from fullrange safety assessment obligations with the aim of costs cutting. Reduced fees should be applied only to the chemicals that pose no potential risk to the environment and human health. The tonnage range from 10 to 100 tonnes p.a. For substances manufactured or imported in quantities of 10 tonnes or above, a chemical safety report incorporating safety and risk assessment data must be submitted. Usage information

2.3 REACH Regulation

21

Fig. 2.2 REACH registration timescale

and relevant risk management measures brought forward to consumers are used as a supplement to safety data (Fig. 2.3). Evaluation is a check of registration dossiers. REACH provides for three different evaluation processes: • Compliance check (e.g., for individually submitted dossiers). The Agency checks the compliance of submitted registration dossiers with legal requirements, which includes revision of the dossier and submission of an updated version by registrants, if necessary. • Substance evaluation. The Agency clarifies suspicion that a substance may constitute a risk to human health and to the environment by requesting further information on the manufacturing process of the substance. As a result of the evaluation process, the Agency can impose authorization procedures, production restrictions or forward the information on a substance to the competent authorities that will make conclusion for any possible follow-up actions. Authorization. Any manufacturers, importers, and downstream users wishing to market or use of the Substances of Very High Concern (SVHC) must receive a special authorization. Among these are CMR substances (carcinogenic, mutagenic, or reprotoxic substances), PBT (persistent, bioaccumulative, and toxic), vPvBs (very

22

2 Aims of Green Chemistry

Fig. 2.3 Chemical use conditions

persistent and very bioaccumulative). Substances identified as Persistent, Bioaccumulative, and Toxic (PBT) and very Persistent and very Bioaccumulative (vPvB) must be substituted with less hazardous alternatives, while carcinogenic and mutagenic chemicals are subject to less stringent conditions if accompanied with documenting that the risks arising from the manufacture or use of the substance are adequately controlled. In this case, the safe threshold is introduced to ensure human exposure is well below this threshold level. In case less hazardous alternatives are not available, the replacement must take place at a later stage, while the replacement time is fixed on a case-by-case basis. Restriction. Restrictions are a legislative tool used to protect human health and the environment from unacceptable risks posed by chemicals. Classification and labeling. REACH offers new classification and labeling systems. There are three main notions that are used in the REACH Regulations: substance, mixture, and article. • Substance is a chemical element and its compounds in the natural state are obtained by any manufacturing process, including any additive necessary to preserve its stability and any impurity deriving from the process used, but excluding any solvent which may be separated without affecting the stability of the substance or changing its composition. • Mixture means a mixture or solution composed of two or more substances. • Article means an object which during production is given a special shape, surface, or design, which determines its function to a greater degree than does its chemical composition.

2.3 REACH Regulation

23

REACH examines the registered substances on the basis of various international instruments rooted in the Recommendations of the Organisation for Economic Cooperation and Development. The Regulations cover all industries, e.g., hydrocarbon processing, textiles, electronics, automobiles, construction materials, steel, pulp, and paper. REACH is applicable to all substances. Only a few substances have been excluded. These include the following: • • • • •

Radioactive substances; Substance with tonnage under 1 ton per year; Wastes; Substances under customs supervision; Substances used for the purposes of Product and Process-Oriented Research and Development (PPORD); • Polymers and Non-isolated intermediates; One of the REACH’s main tools that accompanies the substances and mixtures manufactured in quantities of 1tonne or above per year along the supply chain is the Safety Data Sheet (SDS). Safety data sheets include detailed information on a registration agency, properties of the substance (or mixture), intended use, and classification and labeling data as provided by the Globally Harmonized System (GHS) as well [2]. It ensures that suppliers communicate enough information about the hazards and instructions for handling, disposal, and transport of the substances and mixtures. The Safety Data Sheet contains 16 headings: (1) Identification of the substance or mixture and of the supplier; (2) Hazards identification; (3) Composition/information on ingredients; (4) First aid measures; (5) Firefighting measures; (6) Accidental release measures; (7) Handling and storage; (8) Exposure controls/personal protection; (9) Physical and chemical properties; (10) Stability and reactivity; (11) Toxicological information; (12) Ecological information; (13) Disposal considerations; (14) Transport information; (15) Regulatory information; and (16) Other information including information on preparation and revision of the SDS. As stated above, all substances registered at and above ten tonnes per year, which meet the classification criteria, must be accompanied by the Chemicals Safety Report (CSR). It documents the chemical safety assessment and provides information to all users of chemicals through the exposure scenarios. An exposure scenario is a set of conditions that describe how a substance is manufactured or used, and the measures necessary to control exposure to humans and releases to the environment. The figure below represents the algorithm for REACH’s Registration and Evaluation procedures (Fig. 2.4). The aim behind the REACH regulations is to control the production and use of chemicals within the European Union. It directly affects the wide range of suppliers in various industries, importers, retailers, and consumers of chemical products across the EU. However, a significant influence is exercised on the export companies that supply products to the EU market. The exporters from the USA, China, Canada, Japan, and South Korea in cooperation with the European partners are actively

24

2 Aims of Green Chemistry

Fig. 2.4 REACH registration algorithm

engaged in the registration process focused on the substances, mixtures, intermediates, and articles supplied to the EU market. The overall attitude among the different countries to REACH is yet rather ambiguous. The REACH legislation has been under discussion at the WTO since March 2003. During 16 TBT Committee (Committee on Technical Barriers to Trade) meetings, 23 states (Argentina, Australia, Brazil, Canada, Chile, China, Columbia, Costa Rica, Cuba, the Dominican Republic, Ecuador, Egypt, El Salvador, Japan, South Korea, Mexico, Malaysia, Singapore, South Africa, Thailand, Taipei, Uruguay, and the USA) expressed their concerns and commented on the REACH legislation. As the implementation process unfolds, several negative aspects, such as high red tape, high processing, examination and registration expenditures, increase in the cost of products (by 5%–15%), drop in the cheap goods segment (an estimated 5%–10% of all goods will be withdrawn from the market), decreased exportability of the EU industries, moving of production to the other countries, modification of formulation and technologies due to the substitution of the ingredients supplied by the third countries, are considered as the main drawbacks of the REACH Regulations. In general, both the US chemical industry and the government are ranged against the REACH system. The implementation of REACH, in the U.S view, may well narrow the range of choice for the consumers through restrictions imposed on four toxic substances, namely acrylonitrile, propylene oxide, 1,3-butadiene, and phenol. Standing on the common ground of opposition to REACH, Germany’s also joined the US-led coalition. The UK chemical industry deems it necessary to bring the REACH system in line with the national industry and chemical regulations. The Belarusian State Committee for Standardization carries out a package of measures to coordinate the work of the industry under the new EU technical legislation. These include but are not limited to establishing an Interagency Task Force,

2.3 REACH Regulation

25

creation of a permanent expert panel, holding seminars focused on the interpretation of key provisions of Directive 2006/121/EU and Regulation 1907/2006. The state enterprises were canvassed on the products exported to the EU that falls within Directive 2006/121/EU and Regulation 1907/2006. 17 enterprises (e.g., Belaruskali, Naftan, Grodno Azot, BelFert etc.) were pre-registered in compliance with the REACH Regulations. From there, by implementing REACH, the EU seeks to limit trade in hazardous and highly hazardous chemicals and conduct in-depth examinations of substances to assess the potential hazard levels. Though the administrative expenses tied to 11 years adjustment period for REACH are estimated at approximately 2.3billion euros, business expenditure associated with registration and examination of chemicals—at 2.8–3.6 billion euros and the REACH reform with an aggregate value of 13–30 billion euros, analytics predict the occupational safety and health profit will amount to 17–54 billion euros [3]. It bears mentioning that, besides the REACH Regulations that prevail across the EU, there are also several other obligatory legally formalized initiatives concerning safe handling practices (e.g., Chemical Assessment and Management Program, ChAMP (the USA), National Industrial Chemicals Notification and Assessment Scheme, NICNAS (Australia), Toxic Chemicals Control Act, TCCA (South Korea), etc.). In the year 2010 [4], the MEP of China released the revised version of the Provisions on Environmental Administration of New Chemical Substances. The new regulation replaced the old regulation issued in 2003 and came into force on October 15, 2010. This regulation is similar to EU REACH and is also known as China REACH or China New Chemical Substances Notification (NCSN). Under this regulation, companies shall submit new chemical substance notification to the Chemical Registration Centre (CRC) of the MEP for the new chemicals irrespective of annual tonnage, i.e., chemicals other than the approximately 45,000 substances currently listed on the Inventory of Existing Chemical substances Produced or Imported in China (IECSC). The notification not only applies to new substances on its own, in preparation or articles intended to be released, but also applies to new substances used as ingredients or intermediates for pharmaceuticals, pesticides, veterinary drugs, cosmetics, food additives, feed additives, etc. Earlier in 2003, the “Measures for the environmental management of new chemical substances” (the ‘Measures’) was introduced by China’s MEP [5]. The Measures presented new obligations and challenges for non-Chinese companies exporting and producing new chemical substances in China. However, China REACH is a general term for legislation covering hazardous, toxic, and new chemical substances (Fig. 2.5), while the Measures for environmental management of new chemical substances specifically regulate new chemical substances. There are some differences between the EU and China REACH [6]. For example, the requirement for registration/notification of polymers demonstrates a different approach under EU REACH and China NCSN (Fig. 2.6). EU REACH exempts the registration of the polymer itself, but requires the registration of its monomers. China NCSN requires the notification of polymer itself if it is considered a new

26

2 Aims of Green Chemistry

Fig. 2.5 Overview of chemical management in China

Fig. 2.6 Similarities and differences between EU REACH and China NCSN

chemical in China. Moreover, China NCSN has not stated a threshold tonnage band for exemption, which in practice means that if a very small quantity of a new chemical is imported or manufactured, it will require notification (either simplified notification or scientific record notification).

2.4 Globally Harmonized System …

27

Fig. 2.7 The HMIS labelying for hazardous material

2.4 Globally Harmonized System of Classification and Labeling of Chemicals

(1)

Chemical classification and labeling system

In an effort to raise the awareness of the hazardous properties of chemicals many countries have elaborated their proper systems of classification and labeling ensuring safe production, transportation, and handling of these substances. For instance, labeling requirements are incorporated into the Law on Chemicals (Finland), the Act on Dangerous Products (Canada), and the Hazardous Materials Identification System (the USA). HMIS uses four color-coded bar symbols with blue indicating the level of health hazard, red for flammability, yellow for a physical hazard and white for personal protection. White section indicates which personal protection equipment should be used when working with the material. The number ratings range from 0 to 4 (Fig. 2.7). Each of these systems reflects local specifics and thus is not compatible with each other. For this reason, one product can sometimes be marked with different labels and annotations featuring several different systems simultaneously. Entering the global market manufacturers and importers are bound to mark and classify chemicals in compliance with the systems of the states they trade with. In 1992, the negotiation on the globally harmonized system of classification and labeling of chemicals (Global Harmonized System, GHS) was launched at the UN Conference on Sustainable Development. In 2002, at the World Summit on Sustainable Development, GHS was recommended to be implemented by virtue of respective national and international instruments by 2008. However, Regulation № 1272/2008 (“GHS”) came into force only on January 20, 2009. The gradual transition toward the new system is to be made by June 1, 2015, when the preceding regulations are eventually revoked.

28

(2) • • • •

2 Aims of Green Chemistry

The GHS label elements that are subject to harmonization: Hazard classes, Symbols (hazard pictograms), Signal words, and Hazard and precautionary statements.

Hazard classes: Hazards are generally subdivided into three categories: physical, health, and environmental hazards. GHS recognizes the following physical hazards: (1) Explosives; (2) Flammable Gases; (3) Flammable Aerosols; (4) Oxidizing Gases; (5) Gases Under Pressure; (6) Flammable Liquids; (7) Flammable Solids; (8) Self-Reactive Substances; (9) Pyrophoric Liquids; (10) Pyrophoric Solids; (11) Self-Heating Substances; (12) Substances which, in contact with water emit flammable gases; (13) Oxidizing Liquids; (14) Oxidizing Solids; (15) Organic Peroxides; and (16) Corrosive to Metals. Health Hazard: (1) Acute Toxicity; (2) Skin Corrosion/Irritation; (3) Serious Eye Damage/Eye Irritation; (4) Respiratory or Skin Sensitization; (5) Germ Cell Mutagenicity; (6) Carcinogenicity; (7) Reproductive Toxicology; (8) Target Organ Systemic Toxicity—Single Exposure; (9) Target Organ Systemic Toxicity— Repeated Exposure; (10) Aspiration Toxicity. Environmental Hazard: (1) Aquatic Hazard; (2) Ozone Layer Hazard. Symbols (hazard pictograms): There are nine pictograms conveying health, physical, and environmental hazard information, assigned to a GHS hazard class and category. Phasing out the prior Regulation 67/548/EEC pictograms, GHS designed new symbols for carcinogenicity and products that contain gas under pressure. Furthermore, the toxicity pictogram has also changed and is now represented by Exclamation Mark Symbol (Fig. 2.8). Signal words: The signal word indicates the relative degree of severity a hazard. The signal words used in the GHS are “Danger” for the more severe hazards, and “Warning” for the less severe hazards. Signal words are standardized and assigned to the hazard categories within endpoints. Some lower-level hazard categories do not use signal words. Hazard and precautionary statements: H-phrases (Hazard statements) assigned a unique alphanumerical code to provide a brief description of the main hazard associated with exposure to the product. The alphanumerical code includes ciphered information on the nature and degree of the hazard. The first digit of the code represents the hazard type and the other two serve for the consecutive numbering of the

Fig. 2.8 GHS symbols (A) and Regulation 67/548/EEC symbols (B)

2.4 Globally Harmonized System …

29

H-phrases (Table 2.1). P-phrases (Precautionary statements) are designated similar codes that are intended to form a set of standardized phrases giving advice about the correct handling of chemical substances, which can help to minimize or prevent adverse effects associated with exposure to the product. At present, approximately 65 countries have adopted GHS or are in the process of adopting GHS (Table 2.2). Table 2.1 The examples of H- and P-phrases Hazard statement

H-phrase

Physical hazard

H201—Explosive

Health hazard

H300—Fatal if swallowed

Environmental hazard

H400—Very toxic to aquatic life

Precautionary statements

P-phrase

General precautionary statements

P101—If medical advice is needed, have a product container or label at hand

Prevention precautionary statements P202—Do not handle until all safety precautions have been read and understood Response precautionary statements

P310—Immediately call a POISON CENTER or doctor/physician

Storage precautionary statements

P402—Store in a dry place

Disposal precautionary statements

P502—Dispose of contents/container in accordance with local/national/international regulation (to be specified)

Table 2.2 GHS countries

Argentina France

Malta

South Africa

Australia

The Gambia

Mauritius

South Korea

Austria

Germany

Mexico

Spain

Belgium

Greece

Myanmar

Sweden

Bolivia

Hungary

New Zealand Switzerland

Brazil

Iceland

Nigeria

Thailand

Brunei

Indonesia

Norway

The Czech Republic

Bulgaria

Ireland

Paraguay

The Netherlands

Cambodia Italy

Poland

The Philippines

Canada

Japan

Portugal

The U K

Chili

Laos

Romania

The USA

China

Latvia

Russia

Uruguay

Cyprus

Liechtenstein Senegal

Vietnam

Denmark

Lithuania

Serbia

Zambia

Ecuador

Luxemburg

Singapore

Estonia

Madagascar

Slovakia

Finland

Malaysia

Slovenia

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2 Aims of Green Chemistry

References 1. Bergkamp L (2013) The European Union reach regulation for chemicals: law and practice. Oxford University Press, New York 2. Li ZJ, Zheng JG (2020) Information quick reference manual for hazardous chemicals: GHS and TDG classification and identification of hazardous chemicals catalogue. Chemical Industry Press, Beijing 3. Xu WM (2019) Responsible care and safety technology. Chemical Industry Press, Beijing 4. Provisions on Environmental Administration of New Chemical Substances. http://www.mee. gov.cn/gkml/hbb/bl/201002/t20100201_185231.htm. Accessed 19 Jan 2010 5. Ministry of Commerce of the People’s Republic of China, Environmental Management Measures for New Chemical Substances. http://www.mofcom.gov.cn/article/b/g/200405/200 40500221112.shtml 6. BACL. http://www.baclcorp.com.cn/show.asp?para=en_2_49_1188

Chapter 3

Applications of Green Chemistry

Abstract The implementation of green chemistry principles and green technology makes the process of organic synthesis safer. From the green chemistry point of view, E-factor, atom efficiency, or atom economy are generally accepted new criteria to measure the effectiveness of the organic chemical reactions. Green chemistry also enjoys the advantage of catalytic reactions. Catalysts can be of several types including homogeneous catalysts, heterogeneous catalysts, biocatalysts, and as well as phase-transfer catalysts. Chemical synthesis has to be environmentally friendly, whereas the majority of the solvents applied now are volatile organic substances that are inflammable, explosive, and harmful to the environment. In this regard, there are several alternative approaches in green chemistry including solvent less chemistry, use of dimethylcarbonate, carrying out reactions at supercritical conditions, use of ionic liquids, and as well as the use of the fluorous biphasic systems. Green chemistry should have green reactions and technologies. Following the 12 principles of green chemistry which require a certain strategy and expertise, commonly the set of indicators are used for assessing the critical points of the process. The safety analysis is a systematic study of the process, aimed at identifying potential causes of accidents, risk assessment, which they represent, and finding measures to reduce this risk. The substitution of hazardous materials by more benign ones is a core principle of green chemistry, and a key feature in ISD (Inherently safer design). Keywords Green chemical synthesis · Green catalysis · Green solvents · Process safety · Process intensification

3.1 Green Chemical Synthesis 3.1.1 Chemical Reaction Efficiency Organic synthesis forms the basis for the production of such essentials as polymers, pharmaceuticals, pesticides, coloring agents, synthetic fiber, food additives, etc. On an industrial scale, it is an energy-intensive, reagent-, catalyst- and solventconsuming process, both during the reaction and after its completion, since the end-product needs to be isolated, purified, packaged, and direct it forward to the © Zhejiang University Press 2021 T. Savitskaya et al., Green Chemistry, https://doi.org/10.1007/978-981-16-3746-9_3

31

32

3 Applications of Green Chemistry

Fig. 3.1 Typical chemical processes

consumer. A number of problems associated with the health and environmental impact of chemicals arise during these stages. The implementation of green chemistry principles and green technology makes the process of organic synthesis safer. A typical chemical process generates products and wastes from raw materials such as substrates, solvents, and reagents. If most of the reagents and the solvent can be recycled, it can help to cut and prevent waste. Thus, the mass flow looks quite different (Fig. 3.1). A similar result can be achieved by replacing reagents and catalysts and changing reaction conditions. Green chemistry is a reduction process, which reduces materials and energy consumption, risk and hazard, waste, and, hence, the total cost of the process. Several criteria for a quantitative assessment of the efficiency of the synthesis were established, among which yield and selectivity are regarded as conventional ones. The percentage yield can be calculated using the mass of the actual product obtained and the theoretical mass of the product multiplied by 100% calculated using the balanced equation of the reaction. Selectivity is defined as the number of moles of desired product per the number of moles of converted substrate multiplied by 100%. Measures of Reaction Efficiency: %yield = 100 ×

actual quantity of products achieved theoretical quantity of products achievable

If 81.56 g of maleic anhydride has been produced from 78.11 g of benzene the yield can be calculated as (81.56/98.06) × 100% = 83.17% (Scheme 3.1). Yield is an effective measure of the efficiency of a particular reaction. It is not a good measure for comparing efficiencies between different reactions. If 1 mol of toluene reacted completely and 0.37 mol of nitrotoluene has been produced, the selectivity is (0.37/1.00) × 100% = 37% (Scheme 3.2).

3.1 Green Chemical Synthesis

33

Scheme 3.1 The production of maleic anhydride

Scheme 3.2 The production of nitrotoluene

Organic chemists also recognize the following types of selectivity: chemoselectivity, diasterioselectivity, enantioselectivity, regioselectivity, and stereoselectivity. Measures of the effectiveness of the chemical reaction are named metrics in other worlds. From the green chemistry point of view, it is now generally accepted that new criteria of the (potential) environmental acceptability of chemical processes are E-factor, atom efficiency, or atom economy. The term “atom economy” was coined by Barry Trost in 1991. The terms “atom selectivity” and “atom utilization” are also used as synonyms for atom economy. In particular, for general reaction A + B → C, atom efficiency is calculated as the ratio of molecular weight of product C to molecular weight of reactants A and B. However, this method for efficiency estimation cannot be used as a tool for gauging the overall atom efficiency during the multistage process, since the total atom efficiency, in that case, is neither a sum total nor a multiplication of atom efficiencies of all stages. Carbon efficiency and reaction mass efficiency were suggested as alternative ways to measure the efficiency of a multistage synthesis. Carbon efficiency takes into account the yield and the amount of carbon in the reactants that is incorporated into the final product whereas reaction mass efficiency is the percentage of the mass of desired product relative to the mass of all reactants. The drawback of this metric is that the calculation ignores the reagents used for purification and separation of the product. It also does not account for energy use. atom economy, % =

molecular mass of desired product × 100 molecular mass of all reactants

34

3 Applications of Green Chemistry

Some of the reaction types are considered as noneconomic, wasteful, (e.g., substitution reaction, elimination reaction, and organometallic and oxidation reactions as well) (Schemes 3.3 and 3.4). The atom economy for the substitution reaction is 120.5/(102 + 119) h 100% = 54.5% and for the elimination reaction is 42/(122 + 112) x 100%=17.9%. The impact of the nature of an oxidant in terms of atom economy can be revealed by comparing the oxidation of benzoic acid with metal derivatives and its catalytic oxidation with oxygen. In the former, atom economy = 360/860 × 100 = 42%. In the latter, atom economy = 120/138 × 100 = 87% (Schemes 3.5 and 3.6). A pertinent example of economic reactions is rearrangement reactions (The Claisen’s rearrangement) and addition reactions (e.g., halogenation of alkynes) (Schemes 3.7 and 3.8). Metathesis (from the Greek meta tithemi—“change place”), which is basically an exchange of atoms and groups of atoms between molecules (e.g., olefin metathesis or scrambling, ring-opening metathesis polymerization, cross-metathesis, alkylation), since starter compounds together with auxiliary substances are for the most part included in the end-product. For example, the Phillips “Triolefin Process” developed by Phillips Petroleum is used to convert propylene into ethylene and linear butene in the presence of a catalyst (molybdenum oxide, molybdenum hexacarbonyl supported

Scheme 3.3 Substitution reaction

Scheme 3.4 Elimination reaction

Scheme 3.5 Oxidation of benzoic acid with metal derivatives

Scheme 3.6 Catalytic oxidation of benzoic acid with oxygen

3.1 Green Chemical Synthesis

35

Scheme 3.7 The reaction of Claisen’s rearrangement

Scheme 3.8 Halogenation of alkynes

on aluminum oxide). An atom economy of 100% is typical for the Diels–Alder’s reaction, in particular when used for cyclohexene synthesis (Scheme 3.9). The Diels–Alder’s reaction is a [4 + 2] cycloaddition between a conjugated diene and a dienophile. In a normal demand Diels–Alder’s reaction, the diene component has Electron-Donating Group (EDG) and the dienophile has an electron-withdrawing group. The less common inverse electron demand Diels–Alder’s reaction cycloaddition between an electron-rich dienophile and an electron-poor diene. One of the common examples of the Diels–Alder’s reaction is the synthesis of norbornene from cyclopentadiene and ethylene (Scheme 3.10).

Scheme 3.9 Halogenation of alkynes

36

3 Applications of Green Chemistry

Scheme 3.10 Synthesis of norbornene from cyclopentadiene and ethylene

3.1.2 E-Factor E-factor, defined as the mass ratio of waste to the desired product, appeared to be more demonstrative in terms of environmental impact. E-factor =

Mass of wastes Mass of product

This metric was established by Roger Sheldon in 1992 and is generally accepted as one of the useful measures of the (potential) environmental acceptability of chemical processes. This metric adds yet an element of uncertainty associated with the recommendations on how the solvents, which are utilized, for instance, by combustion, should be factored in as this also generates waste (mostly as carbon dioxide). Table 3.1 illustrates the E-factor increases dramatically ongoing downstream from being the lowest in the oil refining sector ( 90%

Involved in 90% at 28 days), has no effect at 1000 mg/l for fish; low-toxic (the median lethal dose (LD50 ) for ingestion is 13 g/kg (rat). One more advantage is a simple synthetic procedure. DMC has been produced for a long time from phosgene and methanol (Scheme 3.25). In this synthesis, HCl was an unwanted side product. Since the mid-80s, DMC is no longer produced from phosgene, but by oxidative carbonylation of methanol with oxygen through a process developed by Enichem (Italy) (Scheme 3.26). Such non-phosgene scheme was patented in 1984. The most relevant features of this process are low-cost and widely available raw materials with low toxicity, high production rates, nontoxic, easy disposable by-products (carbon dioxide and water), and high-quality product. The drawback of oxidative carbonylation of methanol is a difficult allocation of product because of the formation of azeotropic mixtures between water and DMC as well as between DMC and methanol. Distillation under pressure and the use of special membranes for azeotrope removal has been offered to obtain pure DMC.

3.3 Green Solvents

59

Another industrial procedure developed and industrialized in China is the cleavage of cyclic carbonates. Importantly, this synthesis does not use any chlorine. The process is carried out in two stages: oxides of calcium or magnesium and substituted zeolites are used as catalysts at the first and the second stage, respectively (Scheme 3.27).

Scheme 3.27 The cleavage of cyclic carbonates

Where R = H or CH3 (2)

DMC application

DMC, produced nowadays by a clean process, possesses properties of no toxicity and biodegradability, which makes it a true green reagent to be used in syntheses that prevent pollution at the source. DMC represents an attractive eco-friendly alternative to methyl iodine being an evident carcinogen and used for phenol methylation (Scheme 3.28). Green methylation reaction (Scheme 3.29). DMC-mediated methylations are catalytic reactions that use safe solids (alkaline carbonates) avoiding the formation of undesirable inorganic salts as by-products. In fact, the leaving group, methyl carbonate, decomposes giving as of products only methanol and CO2 . The high selectivity in methylation reactions is due to the ambient electrophilic character of DMC which reacts on its hard center (the carbonyl group) with harder nucleophiles and on its soft one (the methyl group) with softer nucleophiles, according to the Hard–Soft Acid and Base (HSAB) theory [6]. DMC can be used for thiols methylation (Scheme 3.30). DMC having a very selective behavior in reactions with different nucleophiles can be also used as a carboxymethylating agent. For example, the reaction between DMC and amines to carbamates is of strong interest for the industrial field, mainly as they

Scheme 3.28 Phenol methylation

Scheme 3.29 Green methylation reaction

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Scheme 3.30 Thiols methylation

represent the first step of non-phosgene route to the production of isocyanates, in fact, isocyanates can be produced by thermal decomposition of carbamates (Scheme 3.31). In addition to the production of isocyanate without phosgene, carbamates themselves are relevant industrial products because they can be applied mainly in the pharmaceutical and in crop-protection sectors. The biological activity of carbamates was discovered in the 1920s when a German-born pharmacologist and psychobiologist Otto Loewi determined the biomechanical mechanism for the effects of physostigmine (also known as eserine) on the body. Physostigmine occurs naturally in the Calabar beans (Fig. 3.12). In 1929, analogs of physostigmine were synthesized. Today more than 1000 derivatives of carboamine acid are known. DMC is also used for carboxymethylation of alcohols (Scheme 3.32).

Scheme 3.31 The reaction between DMC and amines to carbamates

Fig. 3.12 Physostigma Venenosum or Calabar beans

Scheme 3.32 DMC is used for carboxymethylation of alcohols

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DMC was suggested to be used in gasoline or diesel fuel replacing methyltert-butyl ether (MTBE). By turn, in the US, MTBE has been used in gasoline at low levels since 1979 to replace tetraethyl lead and to increase its octane rating helping prevent engine knocking. MTBE is manufactured via the chemical reaction of methanol and isobutylene. Methanol is derived from natural gas, and isobutylene is derived from butane obtained from crude oil or natural gas, thus MTBE is derived from fossil fuels. MTBE was phased out due to concerns over its toxicity and groundwater contamination. DMC has been of interest as an oxygenate additive to diesel fuel because of its high oxygen content. It has the potential to improve the combustion and fuel efficiency of the entire gasoline pool, simultaneously reducing harmful emissions. In the simulations of DMC in the flame, it was determined that much of the oxygen in DMC goes directly to CO2 . This characteristic reduces the effectiveness of DMC for soot reduction in diesel engines. DMC can be manufactured from domestic and renewable feedstock and be used without any modification to engines or fuel distribution systems.

3.3.3 Reactions at Supercritical Conditions The supercritical fluids proposed as an alternative to traditional solvents have attracted the attention of chemists for the past 150 years. There was a surge of fundamental studies on supercritical fluids in the early 1980s. They have been applied in the industry (total plant capacity amounted to 100000 tons per year) for the extraction of caffeine from coffee and tea (patented in 1974), the aromatization extraction in the brewing process, the extraction of aromatic substances from herbs and spices, deasphalting, etc. However, at that time new solvents were too expensive. In this connection, the interest in them disappeared, but now the situation has changed. Recent studies have shown that supercritical fluids allowed such a level of control and conversion in chemical reactions that were difficult to reach by traditional methods. The fluid is said “supercritical” when it is heated above its critical temperature and compressed above its critical pressure (Fig. 3.13). This particular behavior of substances was first observed in 1822 by French engineer and physicist, Charles Cagniard de La Tour in his famous cannon barrel experiment. It was then defined as supercritical fluid by Irish chemist, Thomas Andrews. The substance in the supercritical phase is represented by free molecules and an ensemble of bound molecules (clusters). The distances between the particles (molecules and clusters) in the supercritical phase are significantly higher than in liquid, but much less than in gases. Molecules are arranged randomly inside clusters and the interaction energy of molecules is not high. At the same time, the individual molecules enter in clusters and leave them at very high speed. In short, supercritical fluid has the properties of both a gas and a liquid. The gas-like diffusivities of supercritical fluids are typically one to two orders of magnitude greater than liquids, allowing for exceptional mass-transfer properties. Moreover, near-zero

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Fig. 3.13 Phase diagram of a pure component

surface tension as well as low viscosities similar to gases, allow supercritical fluids to easily penetrate a microporous matrix material to extract desired compounds. The synergistic combination of density, viscosity, surface tension, diffusivity, and pressure and temperature dependence, allow supercritical fluids to have exceptional extraction capabilities. Supercritical fluids have the ability to dissolve nonpolar substances, including solids, hydrogen, and other gases. They are eco-friendly and provide high efficiency of processes. Critical parameters of the most commonly used substances vary quite widely (Table 3.5). Water is convenient from an economic and environmental point of view, but, unfortunately, the organic substances are usually not soluble in water. However, at high temperatures, water becomes less dense and less polar. It becomes more like an organic solvent (due to reduction in H-bonding). At high temperatures, water also becomes more ionic (more acidic and more basic, due to increased [H3 O+ ] and [OH− ]). At 300 °C, water behaves similarly to acetone. As a result, water in the subcritical phase (pressure: 15–100 bar, temperature: 150–250 °C) can solubilize hydrophobic compounds. In supercritical water, organic compounds and gases become highly miscible. Applications of sub- and supercritical water are very promising and some are in the process of industrialization. Processes using such water are called hydrothermal processes. For example, hydrogenation reaction is possible in supercritical water. In Table 3.5 Critical parameters of some substances Substance

CO2

Temperature, °C

31

Pressure, bar

73

C2 H4

NH3

C2 H5 OH

H2 O

9

132

243

374

50

111

64

218

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Scheme 3.33 The hydrogenation reaction

this case, sodium formate can be advantageously used as a reducing agent and safer hydrogen source than the direct use of gas (Scheme 3.33). Many agencies and industries are also considering the use of supercritical water for waste remediation. However, the critical point of water is much higher than other substances which are more used than supercritical water. Thus, the use of supercritical ammonia is promising, for example, for amination of alcohols, ammoxidation of paraffins and olefins, etc. The conversion of triglycerides into biodiesel is carried out in supercritical alcohols. The critical parameters allow alcohols to react under relatively mild conditions at high speeds. Typically, the process duration is 5–40 min and an excess of alcohol is used. Reactions using supercritical alcohols are noncatalytic that promote easier product isolation. Supercritical carbon dioxide (IV), scCO2 is the most frequently used “green” solvent in various chemical processes [5]. 90% of supercritical technologies focus on supercritical CO2 . It has a number of advantages such as a small explosibility and flammability risk, volatility, as a consequence, a small quantity of waste, high solubility of light gases (O2 , N2 ), and inactivity. Supercritical CO2 is used for the synthesis of the organic compounds, including metal complexes in hydrogenation and oxidation reactions, radical polymerization of fluorinated monomers, and extraction, including from the solids. Reactions in scCO2 media are both environmentally friendly and more effective. For example, hydrogenation is often difficult because of the poor solubility of hydrogen in organic solvents. The supercritical scCO2 as a solvent, hydrogen, and substrate are in the same phase. In such conditions, hydrogen is more soluble that allows achieving its concentrations 10–20 times higher than in traditional solvents. Thus, the process proceeds more rapidly, continuously, and in some cases more selectively. For example, in the reaction of isophorone hydrogenation to 3methylcyclohexene the specific double bonds are only affected which reduces the amount of by-products (Scheme 3.34). This process was developed by Thomas Swan & Co. Ltd. (UK) and implemented commercially. The hydrogenation process was the first synthesis carried out at supercritical conditions. Research Development Corporation of Japan developed an effective method for the catalytic hydrogenation in scCO2 leading to formic acid. In this case, scCO2 is used as a reagent (Scheme 3.35). The high ability of scCO2 to solve hydrogen allowed the pharmaceutical company “Roche” to replace a static 10 000 L reactor with a dynamic 40 L supercritical reactor for the hydrogenation process.

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Scheme 3.34 The reaction of isophorone hydrogenation to 3-methylcyclohexene

Scheme 3.35 The catalytic hydrogenation in scCO2 leading to formic acid

The supercritical CO2 oxidation of cyclohexene results in adipic acid (Scheme 3.36). RuO4 is required for the main reaction which is formed as a result of RuO2 oxidation in the aqueous phase. ScCO2 also applies in fluoropolymer technology due to its ability to solve the fluorinated organic compounds, for example, radical polymerization of fluorinated monomers (Scheme 3.37). The process of producing the polyester-polycarbonates from propylene in scCO2 is also well known (Scheme 3.38). Supercritical fluid extraction represents another, major analytical application. For example, the caffeine from the green coffee beans is extracted now commercially

Scheme 3.36 The supercritical CO2 oxidation of cyclohexene results in adipic acid

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Scheme 3.37 Radical polymerization of fluorinated monomers

Scheme 3.38 Producing the polyester-polycarbonates from propylene oxide in scCO2

using scCO2 . Unlike their organic “analogs” (chloroform and methylene chloride not accepted owing to their toxicities) scCO2 extracts only the caffeine without affecting grains containing the aroma components and without any harmful wastes. Furthermore, because of the high extraction capacity of scCO2, the front-end grinding of the coffee beans is not required. Separation and processing using supercritical CO2 are currently online commercially in the food, essential oils industries, etc. (e.g., hop removal in beer production, fat reduction in nuts, crisps, etc., nicotine from tobacco, and extraction of various aromatic substances in the perfume industry.) In Japan, scCO2 is actively used in dry cleaners. Significant advances have recently been made in materials processing, ranging from particle formation to the creation of porous materials. The researchers from the State Key Laboratory of Fine Chemicals (Dalian University of Technology) investigated the effect of the scCO2 pretreatment on reducing sugar yield of lignocellulose hydrolysis [7]. Lignocellulose biomass is a renewable resource and has great potential for the production of economical fuel ethanol because of its cheapness and availability in large quantities. It includes agricultural residue, forestry residue, yard waste, wood products, etc. Lignocellulose biomass mainly consists of cellulose (32%–47%), hemicelluloses (19%–27%), and lignin (5%–24%). The former two components can be hydrolyzed to reducing sugars, which can be fermented into ethanol. However, a quite low sugar yield (< 20% of the theoretical maximum) is usually obtained from enzymatic hydrolysis of lignocellulosic materials without pretreatment due to the protective shield of lignin and the hemicelluloses around cellulose. Three kinds of agricultural residues—corncob, cornstalk, and rice straw—were pretreated in scCO2 at various temperatures, pressures, durations, and raw material moisture content. It was shown that the scCO2 pretreatment had a positive effect on improving the reducing sugar yield of agricultural residues for hydrolysis.

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The methods for isolation of biologically active compounds from medicinal plants using supercritical CO2 extraction are actively developed in the Institute of Biochemistry of Biologically Active Compounds of the National Academy of Sciences (Belarus). The investigations in supercritical CO2 areas are carried out in the Moscow State University, the Institute of Organoelement Compounds of the Russian Academy of Sciences, and other research laboratories. In the past 25 years, the researchers in many countries focus their attention on the Supercritical Fluid Extraction (SFE) of the trace amounts of radioactive and heavy metals for treatment and decontamination of various solid objects (including soils) as well as on SFE of actinide macro amounts for reprocessing of the spent nuclear fuel of the nuclear power plants. For example, the researchers from the Khlopin Radium Institute (St. Petersburg, Russia) developed the fundamental basis of SFE of transuranium elements from soils contaminated as a result of the Chernobyl catastrophe [8]. China has started the investigations on supercritical carbon dioxide power cycle in 2011 and the Nuclear Power Institute of China has been a leader in such area. By the end of the deliberations, it is clear that the magic of the supercritical fluids had captured the scientific imagination of another generation of researches and engineers, now empowered to drive the next phases of development and innovation.

3.3.4 Ionic Liquids The development of new solvents for chemical processes is not limited to the use of supercritical fluids. An important area of “green” chemistry is the use of ionic liquids [9]. In the early 80s, a new class of liquid at room temperature substances based on molten salts was called ionic liquids. In English literature salts that melt at room temperature are referred to as “Room-Temperature Ionic Liquids.” The choice of “room” temperature is quite conditional, because salts that a referred to as ionic liquids have a melting point from 233 K (in some cases from 183 K) to 343 K. The main feature of ionic liquids is that they are viscous liquids containing only ions. In broad terms, IL is any molten salt, usually organic. The first researches of ionic liquids were carried out in 1914 (the preparation of ethylamine nitrate with a melting point of 13–14 ° C). The reaction of concentrated nitric acid with ethylamine was obtained and described in the tidings of the Imperial Academy of Sciences by the Russian chemist Paul Walden. The next time the term “ionic liquid” was mentioned only in 1934, when a patent for a new method of dissolving cellulose at a temperature of 100 ° C was obtained by Granacher. A melt of N-methyl pyridinium chloride has been proposed to dissolve the cellulose (Scheme 3.39). The most diverse types of ionic liquids were synthesized from 1940 to 1980. In 1951, Hurley and Vier published an article on the study of melting systems for ethylpyridinium bromide and metal chlorides (AlCl3 ) for electrodeposition of

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Scheme 3.39 Ionic liquids

aluminum. In the 1960s, a research was made to find low-melting chloraluminates of organic cations for their further use in the electrochemical deposition of aluminum coatings, and also as an electrolyte in batteries of submarines. However, until the 1990s, there were no systematic studies on IL. Since 1990, the “boom” has begun: interest in IL began to grow at an accelerating pace. The term “ionic liquids” does not impose any structural limitations, and therefore such compounds can have both an inorganic and an organic nature. However, inorganic salts have too high melting points, and none of these salts or mixtures thereof is liquid at a temperature close to room temperature. Most inorganic salts melt in the range of 600–1000 °C and are of no practical interest for organic chemistry and organic catalysis. The presence of singly charged asymmetric ions having large size and a “smeared” charge in ionic liquids is preferable (Fig. 3.14). In this case, steric obstacles complicate the crystallization of IL and cause their low-melting point. Ionic liquids are a huge class of compounds that can consist of an organic cation and an inorganic anion, from an inorganic cation and an organic anion or be completely organic. There are also chiral ionic liquids, which were first successfully used as organocatalysts at key stages in the synthesis of chiral drugs and analogues of natural compounds. Potentially there are infinitely many ILs, but in fact, their number is limited by the availability of suitable organic molecules (cations) and inorganic, organic, or metal complex anions. According to various estimates, the number of possible combinations of cations and anions in such compounds is about eight orders of magnitude greater than all known organic substances. Currently,

Fig. 3.14 Sodium chloride (melting point 806 °C, a) and 1-butyl-3-methylimidazolium hexafluorophosphate (melting point 100 °C, b)

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about 500 ionic liquids are described in the literature. The most famous among them have imidazolium, pyridinium, phosphonium as a cation (Scheme 3.40). Hydrocarbon substituents of the cation are used to obtain the specified properties of the IL (for example, a certain melting point, Fig. 3.15). The most commonly used anions are hydrolyzing anions of AlCl4 − , mixed with water BF4 − , hydrophobic PF6 − or bis (triflyl) imide anions (Scheme 3.41). It is not difficult to make an ionic liquid. Synthesis of IL can be reduced to two main stages: Cation formation and anion exchange. A relatively inexpensive and easily synthesized 1-methylimidazole is used to obtain cations (for example, 1-alkylimidazoles) (Scheme 3.42). However, often a cation is commercially available as a halide salt, and it is only necessary to replace the anion to obtain the desired ionic liquid. The following basic methods are usually used: • Reaction of N-alkyl halide with Lewis acids. For example, the reaction of ethylmethylimidazolium chloride with aluminum chloride: [EMIM]+ Cl− + AlCl3 → [EMIM]+ AlCl− 4

Scheme 3.40 Common cations of ionic liquids

Fig. 3.15 Change in the melting temperature of the IL with the length of the hydrocarbon chain

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Scheme 3.41 The most commonly used anions

Scheme 3.42 The synthesis of 1-methylimidazole to obtain cations

It should be noted that the production of ionic liquids with AlCl3 was the dominant method. • Anion exchange reaction. For example, the reaction of ethylmethylimidazolium chloride with hexafluorophosphoric acid:

[EMIM]+ Cl− + HPF6 → [EMIM]+ PF− 6 + HCl You can get an IL even on an industrial scale. However, in this case, not all methods are applicable because of their high cost. In industry, large amounts of

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organic solvents are often used to purge ionic liquids from halogens. These shortcomings should be eliminated when transitioning to multitone synthesis. Solvent Innovation has patented and produces an ionic liquid that has the trade name ECOENG 212 and meets all the requirements of “green” chemistry (nontoxic, is able to decompose in the environment, does not contain halogen, does not use solvents in its production, the only by-product is ethyl alcohol). (1)

Properties of IL

IL are mostly colorless or have a yellowish tinge, which is due to a small amount of impurities. A very important property of ILs is that they remain liquids in a very wide temperature range (−90 °C to 300–350 °C), are thermally stable up to 200 °C, and some up to 400–450 °C. For comparison: for water and organic solvents this range does not exceed 100 °C. ILs have high dissolving power, and not only for inorganic and organic, but also for polymer materials. As a rule, most ionic liquids are nonvolatile and nonflammable, almost all conduct electricity efficiently, are regenerable, and can be reused. Some IL have acidic and superacidic properties, which are important in catalysis. There are also basic ILs. As it was said earlier, the properties of ionic liquids can be easily selected by using various available ions. One of the disadvantages of IL is their high viscosity, which can make it difficult to work with them. (2)

Application of ionic liquids

A unique set of properties of ILs opens wide prospects for their use. Let’s give some examples. Ionic liquids can be used to measure temperature, because they respond faster to temperature changes than mercury, and are able to work in very wide temperature ranges. The ability to obtain homogeneous structures and to regulate the particle sizes is used in the synthesis of nanoparticles using IL (Fig. 3.16).

Fig. 3.16 Liquid mirror and nanoparticles of YF3 based on Y(OAc)3 and bmimBF4 (salt 1-butyl -3-methylimidazolium tetra-fluoroborate)

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71

In 2003, a message has appeared about a fundamentally new type of composite material—”ionic liquid—carbon nanotubes” [10]. Ionic liquid based on dialkylimidazolium in combination with carbon nanotubes gives a mechanically and thermally stable gel. Since ionic liquids and carbon nanotubes have a high conductivity, there is a synergistic enhancement. High conductivity of the mixed type is shown (electronic—in nanotubes, ionic—in ionic liquids). Ionic liquids can be used in the production of liquid mirrors. The first reflective telescope with a parabolic mirror was developed by Newton in 1670. He proposed to use the property of a liquid to form parabolic surfaces when rotating to create a mirror. In fact, the idea was embodied by Robert Wood. Liquid mirrors are much cheaper than conventional mirrors, they have a more perfect surface. The focal length can be changed by adjusting the rotation speed. To obtain mirrors, the surface of the ionic liquid (1-ethyl-3-methylimidazolium ethyl sulfate) is coated with colloidal silver particles measuring several dozen nanometers. Previously, a layer of chromium is applied to the surface of the liquid. The result is a mirror that reflects well in the IR range. 5-hydroxymethylfurfural (HMF) (Scheme 3.43)—a universal replacement for many petroleum products. Traditionally, it is produced using acids as catalysts. HMF is unstable: in acidic media, it decomposes into levulinic and formic acids. As an alternative method, it was proposed to obtain HMF from glucose on a chromium (II) chloride catalyst dissolved in an ionic liquid (1-alkyl-3-methylimidazolium chloride). The yield of the product is 70%, and the content of levulinic acid, in this case, is negligible. Perspective is the usage of IL as electrolytes in batteries of a new type. This contributes to the solution of the problem of rechargeable zinc elements, which is the evaporation and deactivation of electrolyte, and also allows charging the battery to higher voltages. ILs have found application as buffer systems for pH control in chemical reactions. For example, the main component of a widespread class of ionic liquids, in the study of the reaction of imidazolium hydroxide, with phthalic and tartaric acids, an ionic liquid of a new type has been obtained, which plays the role of buffer in a nonaqueous medium. In this ionic liquid, the ratio of the acidic and basic components is 1: 1. It maintains pH during reactions in liquids that do not mix with water.

Scheme 3.43 5-hydroxymethylfurfural

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ILs are used in catalytic processes. In this case, there are two main approaches: use a catalyst that is grown in IL, or IL, specific for this reaction. An example is Friedel–Crafts acylation––the acylation of alkyl aromatic hydrocarbons. This is a very important reaction for fine organic synthesis, but solid catalysts (e.g., zeolites) that are commonly used do not work at full strength: the resulting polar products block acid sites, by-products are formed, the catalyst loses activity. The use of IL in this case opens wide opportunities. Another example is the hydroformylation of olefins on rhodium, platinum, cobalt, or ruthenium catalysts, which are too expensive. Complexes of these metals, dissolved in the imidazolium IL with hexafluorophosphate as an anion, show high activity and selectivity in this reaction, and the catalysts can be reused. ILs have found application in polymer chemistry in the production of composite materials with improved physical and mechanical properties. Across a whole range of physical characteristics, polymers plasticized with ionic liquids are comparable to polymers plasticized with traditional plasticizers (dioctylphthalate), but are more thermally stable. There are examples of IL use in the synthesis of analogues of juvenile hormones of insects, detoxification of persistent polychlorinated organic pollutants, preparation of wound healing preparations of the isoprenoid series. In extracting, among other advantages, ILs are interesting in that their components can serve as hydrophobic counterions. Papers have been published on the extraction of alkali and alkaline earth metals with crown ethers in IL. Chinese researchers studied the extraction of heavy metals IL with dithizone. The extraction of organic compounds in IL is studied better than the extraction of metal ions. The distribution of phenols, ketones, etc., has been studied. The use of IL for amino acid extraction made it possible to achieve practically quantitative extraction (extraction is quantitative even for glycine and other hydrophilic amino acids). The extraction system based on IL was successfully used to extract amino acids from the native solution of microbiological production. Extraction to IL can be used analytically, in particular, the unique electrical conductivity of these solvents allows the electrochemical determination of extracted compounds directly in the extract, without the addition of background electrolyte or reextracting. A number of works on extraction are focused on technological applications. Thus, the distribution of butanol in the water-IL system has been studied with the aim of creating new methods for isolating alcohols from biomass. ILs are potentially interesting for radiochemical applications. Thus, when working with fissile elements (Pu, U), it is important that the critical mass is not accidentally reached: otherwise, a spontaneous fission reaction may begin. This danger was demonstrated by an accident in 1999 at a nuclear fuel production facility in Tokaimura (Japan). For plutonium in aqueous solutions, the risk of a spontaneous reaction is eliminated at a Pu concentration of less than 8 g/l, which is too low for technological applications. In the case of IL, the threshold concentration turned out to be much higher, which is associated with a lower IL relative density compared to hydrogen as

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73

against the water. For example, for tetra-fluoroborate methylethylimidazolium, the threshold is 1000 g/l. In various scientific laboratories of the world, research is being carried out in the field of the extraction of actinides using IL. The extraction of U (VI), Pu (IV), Am (III) from 3 M HNO3 in the presence of phosphonium and imidazolium ILs was studied in the Khlopin Radium Institute(St. Petersburg, Russia). It is shown that IZ additions lead to an increase in the distribution coefficient up to 103 times, which allows to significantly reduce the concentration of the reagent used in case of its application in practice. Thus, ionic liquids are quite capable of replacing traditional organic solvents in a number of processes.

3.3.5 Fluorinated Biphasic Solvents The first reaction using fluorinated alkanes as a reaction medium was carried out in 1993. A year later the term “fluorinated” became an analogue of the term “aqueous” with respect to fluorinated alkanes, esters, or amines. An example of used fluorinated solvents are perfluoromethylcyclohexane, perfluorohexane, etc. (Scheme 3.44). Fluorinated Solvents (FS) are usually synthesized from the corresponding hydrocarbons by electrochemical fluorination or by using cobalt fluoride. Fluorinated solvents are characterized by high density (usually 1.7–1.9 g/cm3 ) and low polarity, low solubility in water and organic solvents, high gas solubility (for example, the fluorine-containing Oxygent ™ emulsion is used to increase oxygen delivery to tissues and organs through the blood). They are chemically inert, nonexplosive, and low-toxic, do not destroy the ozone layer. Since FSs are poorly miscible with organic solvents, they can be used in biphasic reactions where the reagent or catalyst are in the phase of the FS and are easily separated from the organic phase at the end of the reaction. In a number of cases, heating of the two-phase system leads to the formation of a homogeneous mixture in which the main reaction occurs, and then, as a result of cooling the system, the catalyst and reaction products are separated (Fig. 3.17). Such a method is particularly applicable in cases where a nonpolar compound is converted to a polar compound

Scheme 3.44 Fluorinated solvents

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Fig. 3.17 Reaction using fluorinated solvents

during the reaction. In this case, the more polar compound is formed, the lower its solubility in the phase of the FS. There is a definite approach to the design of the structure of molecules of catalysts or reagents soluble in FS. A molecule should include three main components: a fluorinated fragment responsible for solubility in the FS, an organic fragment that shields the reaction group from the electron-donor effect of perfluoroalkyl groups, a functional group that is responsible for the reactivity of the molecule (Fig. 3.18). So far, a fairly large number of processes are known that are carried out with the use of FS. Among them—hydroformylation of olefins (Scheme 3.45). In carrying out this reaction using only organic solvents, the problem arises of separating the aldehydes and the catalyst, with the use of an aqueous organic medium, side reactions with water are possible. The use of fluorine-containing solvents is limited only by their cost. Another example of the use of FS is the production of epoxides (Scheme 3.46).

Fig. 3.18 The main constituents of the molecule

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Scheme 3.45 Hydroformylation of olefins

Scheme 3.46 The production of epoxides

Diels-Alder, Suzuki, Heck reactions, oxidation, polymerization, etc., are also described in the literature using fluorinated solvents. Lastly, we note that when choosing a solvent for a particular process, it is necessary to consider the following factors: (1) the effect that the solvent has on the products of the reaction, its mechanism, speed, or equilibrium; (2) stability of the reactants, reaction products (including intermediate stages), catalyst in the solvent; (3) the appropriate temperature range in which the solvent is in the liquid state, in order to achieve the fastest reaction rate; (4) the cost, which is extremely important in the case of a reaction on an industrial scale.

3.4 Green Design 3.4.1 Twelve Principles of Green Engineering You already know that there are two strategies for solving environmental problems: the strategy of “end of pipe”—solution of the environmental problems when they arise in the production process and strategy to prevent pollution (pollution prevention strategy, P2 ) [12]—solution of the environmental problems before they occur, at the product design stage. Advantages of the second type of strategy are so obvious that even described in children’s books. For example, in the book “The Cat in the Hat Comes Back,” Dr. Suess said that, if you got something in dirty state, the only way to make it clean, means to pollute something else [13]. The best way to keep the world clean, it does not pollute it from the beginning. It is the goal of green chemistry. Green chemistry should have green reactions and technologies. Following this direction, scientists around the world find safe ways to produce not only new but also long-known products. However, even if green synthesis or technology will be developed, the transition from the laboratory to the industrial scale requires a

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certain strategy and expertise. There is no coincidence that Paul Anastas in 2003 formulated 12 principles of green engineering in accordance with the principles of green chemistry [14]. 1.

Inherent Rather Than Circumstantial Designers need to strive to ensure that all materials and energy inputs and outputs are as inherently nonhazardous as possible

2.

Prevention Instead of Treatment It is better to prevent waste than to treat or clean up waste after it is formed

3.

Design for Separation Separation and purification operations should be designed to minimize energy consumption and materials use

4.

Maximize Efficiency Products, processes, and systems should be designed to maximize mass, energy, space, and time efficiency

5.

Output Pulled Versus Input Pushed Products, processes, and systems should be “output pulled” rather than “input pushed” through the use of energy and materials

6.

Conserve Complexity Embedded entropy and complexity must be viewed as an investment when making design choices on recycle, reuse, or beneficial disposition

7.

Durability Rather Than Immortality Targeted durability, not immortality, should be a design goal

8.

Meet Need, Minimize Excess Design for unnecessary capacity or capability (e.g., “one size fits all”) solutions should be considered a design flaw

9.

Minimize Material Diversity Material diversity in multicomponent products should be minimized to promote disassembly and value retention

10.

Integrate Material and Energy Flows Design of products, processes, and systems must include integration and interconnectivity with available energy and materials flows

11.

Design for Commercial “Afterlife” Products, processes, and systems should be designed for performance in a commercial “afterlife”.

12.

Renewable Rather Than Depleting Material and energy inputs should be renewable rather than depleting

3.4.2 Transfer from Green Reaction to Green Industrial Technology These 12 principles of green engineering based on the concept of Eco-design (Design for Environment) allow the product at all stages of their life cycle (production, use, and liquidation) to have a minimal impact on the environment.

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Creating technology of green synthesis one has to understand that the transition from the reaction carried out in the laboratory in a glass flask, to the reaction in an industrial reactor, which has a volume many times greater than the volume of the flask, subjects to certain laws. You can create a green reaction, but do not bring it into the real process. First of all, it is necessary to take into account the so-called scaling effect, which is caused by the difference in heat and mass transfer for reactors of various sizes. There is a correlation between the amount of heat transferred Q, transfer coefficient U, heat-transfer area A, and the temperature difference between the reactants and thermostatic medium T (Scheme 3.47):

FLASK 1 l (10-3m3) 0,05 m2 (50)

REACTOR 10m3 20 m2 (2),

where 2 and 50 are the ratio of surface area to volume of the vessel

Scheme 3.47 The correlation between the amount of heat transferred Q, transfer coefficient U, heat-transfer area A, and thermostatic medium T

In the transition from the flask to the reactor, the volume of the reactants increases faster than the heat transfer area increases. For example, for a 1 L flask heat transfer area is approximately 0.05 m2 and the standard for the reactor 10 m3 − m2 is 20 m2 only, i.e., the ratio of heat transfer area to volume decreases by a factor of 25! (Scheme 3.47). Changing the temperature especially in the case of exothermic reactions leads to the intensification of side reactions and, consequently, reduces the yield and process selectivity. Appears the need for further purification of the product the amount of waste increases. It increases energy consumption and thus increases product cost. Scaling effect does not apply only to green reactions. It takes place for any chemical synthesis on the way from the laboratory to commercial technology. In the process of scaling (the transition from the laboratory to the industrial scale) the type of reactor plays a very important role. Reactor choice and its mode of operation can have a dramatic effect on the overall eco-efficiency of the process. Chemical processes can be divided into two main types, batch and continuous. Most fine chemicals and pharmaceuticals are made in batch reactors whilst the majority of bulk chemicals are made in continuous ones. Semi-batch reactors are used in some cases; these processes involve additional ingredients being added at certain stages into an otherwise batch process. Multipurpose plants tend to go hand in hand with batch processing; these are relatively common in the fine chemicals industry. The main components of a conventional batch reactor are agitator for stirring, baffle, heating/cooling jacket, a thermocouple or other analytical equipment access to the condenser or a distillation column, charging line, drain valve, and the manhole (Fig. 3.19).

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Fig. 3.19 The main components of a conventional batch reactor

Batch reactors are two types of reactors, plug flow reactor and continuous stirred given the same arrival rate of reactants and removal of products of the reaction (Continuous Stirred Tank Reactor, CSTR). In a batch reactor, the concentration of the desired product increases and starting reactants concentration decreases, whereas the concentration change does not occur in a continuous reactor (Fig. 3.20). The feature of the batch reactors is uniformity in product from one batch reactor loading, which is important in the synthesis of pharmaceuticals. The continuous reactor product characteristics may change over time. Selection of the reactor should be based on knowledge of the kinetics, the reaction mechanism, heat elimination, methods for the removal of by-products, etc.

Fig. 3.20 Change of the aimed product and reagents in batch and CSTR reactors

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Fig. 3.21 Photo of microreactors

Approach of green chemistry to scaling up differs from the traditional one as considered a safer approach is not the increasing of the reactor volume but the increasing of the number of small-size reactors. For example, the sequence of smallvolume CSTR reactors has certain advantages in terms of heat transfer rate than a single large volume reactor. Today, many different microreactors have been developed (Fig. 3.21). Some of them can be placed on a laboratory bench and in hands (Fig. 3.22). The limitation for the application of microreactor is the aggregate state of the components. In particular, there are restrictions on the use of microreactors in systems where one component is in a solid state, whereas for liquid–liquid systems, and the liquid–gas systems the reactors with small volume carry out the process safely and efficiently. The correct choice of reactor design minimizes the formation of by-products, allows to optimize energy consumption, reduces the product cost and waste. In addition to the reactor choice, the hardware design process is an important point for the implementation of “green” technology. It will ensure the safety of the process holding.

3.4.3 Process Safety Historically, the approach to the safety assessment process has changed several times. So, in the 30s of the twentieth century, it can be characterized as “Who is to blame? (Behavior),” in the “70s”—What is the reason? (Relations between man and machine (Process), “ in the “80s—“Risk Assessment (Management systems)” and, since the 90 s, it is—”Standardization of risks, green and safe essentially design (Comprehensive).” To date, there is no single methodology for conducting a comprehensive assessment of the process safety. Commonly they use the set of indicators for assessing the critical points of the process. The safety analysis is a systematic study of the process, aimed at identifying potential causes of accidents, risk assessment, which they represent, and finding measures to reduce this risk. There are qualitative, semi-quantitative, and quantitative methods.

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Fig. 3.22 The size of microreactors

As an example, we present a qualitative assessment of the security matrix, which was proposed in 2005 by Jan and Raman [15], and as two main factors considered action and its probability. The intensity of the impact (severity) and the probability (likelihood) were classified as L (low), M (medium), and H (high) (Fig. 3.23). Such an analysis is not complete and is suitable for the initial stage of organization of the production, when the process is still supposed to design. Several semi-quantitative assessment methods have been proposed as well. For example, the method of finding the index of fire and explosion was proposed by Dow (Dow’s fire and explosion index or F & EI) to estimate the probability of an event Fig. 3.23 The security matrix

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and its consequences; the security index (Inherent safety index, ISI), which took into account the safety, which is not just a characteristic of this chemical process and its hardware design and embedded in their nature; the integrated safety index, which considered the product life cycle taking into account the economic efficiency of the process, the risk of the individual stages, etc. In later versions of these methods, chemical reactions and chemical properties have been considered with respect to their potential hazard. Quantitative methods enable us to give a more in-depth analysis of the process on the basis of mathematical models, however, they require large amounts of raw data and long-term calculations. Let us consider a semi-ISI (Table 3.6) method. The safety index, in this case, is divided into two subindices, which, as already mentioned, consider the process from the point of view of the chemist and designer, i.e., the safety of reaction and equipment of the process. As follows from the table, the first two subindex characterizing the safety of the chemical, relate to the characteristics of the reaction, and three—to the characteristics of the chemicals. Indexes characterizing the safety of the process, assess the safety of the equipment. For example, indexes ISBL (Inside Battery Limits Area) and OSBL (Outside Battery Limits Area) characterize the safety of the equipment in which the conversion of the reactants into the final product is carried out, and the equipment in the rest of the enterprise, for example, a large capacity for storing solvents, etc. Let Table 3.6 Safety index

Total safety index (ITL ) Index of chemical safety

Scores Index of process safety

Scores

Subindices for chemical reactions

Subindices for the safety of process conditions

Heat of main reaction, IMR

Equipment list, II

0–5

Heat of side reaction, 0–4 IRS

Process temperature, IT

0–4

Chemical interaction, 0–4 INT

Process pressure, IP

0–4

Subindices for hazardous substances

Subindices for process design

Inflammability, IFL

0–4

Equipment

Explosive, IEX

0–4

ISBL

0–4

Toxicity, ITOX

0–6

OSBL

0–3

Corrosion activity, ICOR

0–2

Process structure, IST 0–5

0–4

Maximum number of 28 scores

Maximum number of 25 scores

Maximum total index, ITI

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3 Applications of Green Chemistry Heat of the reaction/mass of reagents

Scores

Thermally neutral l, ≤ 200 J/g

0

Average ezothermic < 600 J/g

1

Moderately ezothermic< 1200 J/g

2

Strong exothermic< 3000 J/g

3

Exceptionally ezothermic ≥ 3 000 J/g

4

us consider the subindex of the IMR. This is an important feature and it is determined by quantification of the heat of reaction per 1 g of reactants (Table 3.7). Similarly, all the remaining subindices are determined, and then they are added together to determine the maximum total index. The final equation is

The researchers are now offering a variety of methodologies for assessment of the safety of a chemical process based on specific software products to assess the actual process and offer an alternative design for its implementation in accordance with the principle of sustainable development (Sustainable Design). Figure 3.24 presents the necessary input data, which include procurement costs (purchase prices), the cost of waste management (waste treatment prices), cost of sales (sale prices), the balance weight (mass balance), and energy (energy balance) for the real plant and the proposed model (simulation). Furthermore, the technological scheme of the process has to be introduced, for example, by means of graph theory through mass and energy graphs (Fig. 3.25). Next is the calculation and comparison of a variety of process schemes, for example, with the removal of heat and subsequent use of heat and chemicals, etc. At the same time, despite the complexity of the calculations, it is possible to get rather good results. For example, the application of the above methodology allowed

Fig. 3.24 The methodology of the process safety assessment

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Fig. 3.25 The graph theory

to propose an alternative scheme for the synthesis of methyl-tert-butyl ether from isobutene and methanol, in which water flow is used for extraction of methanol was reduced by 20%. However, despite the fact that the standard methods of chemical plant safety forecasting already exist (it will be enough to mention the methodology which is famous as HAZOP study (Hazard and Operability study) for the preliminary safety assessment for the proposing processes or modification of the existing one Now preference has given to strategies for creating a mechanical protection from the dangers (special equipment), and the strict observance of the safety instructions at the enterprise.

3.4.4 Inherently Safer Design Statistics show that today 60% of chemical accidents occur as a result of mechanical failure or operator error. The design concept of an inherently safer design ISD begins with the answer to the question: Is it simply enough to eliminate the risk by changing the process design in order to avoid accidents and incidents in the enterprise? It is important to understand that today, many chemical companies have a design that ensures the safety of the process, but the question is whether the design is safe in fact, by its nature or in other words, whether the safety of the process lies in its core (Fig. 3.26).

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Fig. 3.26 The design concept of ISD

The words of Trevor Kletz [16], an ideologue of ICD “What you do not have can not harm you” reflects this concept well. The concept of the inherently safer design is obliged by his appearance to incidents in Flihsboro and Bhopal. The latter is a classic example of how you can use the ICD strategy to prevent the tragedy. The plant in Bhopal produced the insecticide “Carbaryl”. The synthesis scheme (Scheme 3.48) involved the reaction of methylamine and phosgene with the formation

Scheme 3.48 MIC production

of methyl isocyanate (MIC). Then, MIC reacted with α-naphthol to form a final product carbamate. The most dangerous of these substances are phosgene and MIC. The accident in Bhopal just occurred due to the fact that water got into the large container, where MIC was stored. This caused a rise in pressure and an explosion occurred. A cloud of toxic gases covered the nearby city. More than 300 people were killed and more than 200,000 severely affected. It is important to understand that

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the main issue is not whether, how and why water has got in this capacity, and why cooling did not work, and that is why a large amount of MIC has always been kept at the plant. Following the concept of ISD, the next questions should be asked: is it necessary to use phosgene? Do we need to use MIC? Do we need to keep the MIC or phosgene? On the first question, the answer is “Yes”. And on the second two for this synthesis scheme, we need to answer “No”. In general, there are two approaches to design the safety of a chemical process— either handling the hazards with engineering and management controls or eliminating them altogether [17]. If a process hazard cannot be eliminated, it may still be possible to reduce its potential impact sufficiently as far it is not capable of causing major injury or damage. Whenever feasible, it is appropriate to eliminate or minimize process hazards. Engineering and management controls have been effective in reducing risk to very low levels in the chemical process industries, as demonstrated by the industries an excellent safety record. However, no engineering or management system can ever be perfect, and the failure of these systems can result in separate accidents. There are four major strategies for inherently safer process design: (1) Minimize the size of process equipment; (2) substitute a less hazardous substance or process step; (3) moderate storage or processing conditions; and (4) simplify process and plant design. Reducing the size of Chemical Process Industry (CPI) equipment generally improves safety by reducing both the quantity of hazardous material that can be released in case of loss of containment and the potential energy contained in the equipment. This energy may derive from high temperature, high pressure, or heat of reaction. There are numerous opportunities to minimize the inventory of hazardous materials in a CPI plant without fundamental changes in process technology. Following the accident in Bhopal, India, in 1984, most CPI firms reviewed their operations to identify opportunities to reduce quantities of toxic and flammable materials on hand. These companies did not rebuild their plants using another technology, or make dramatic changes to the process equipment, as both solutions were too costly. Instead, they carefully evaluated existing equipment and operations, and identified changes that would enable them to run with a reduced inventory of hazardous materials [17]. As an example of the lessons learned from this tragedy, we can lead a company DuPont, which at one of its plants in six months after the accident, has introduced a process, in which the MIC was synthesized in the amount of no more than 1 pound. Furthermore, according to the present scheme, the MIC can be eliminated altogether as a reagent. As for phosgene, it is necessary in both cases. Minimization goes much more further than microreactor and storage volume reducing, however. When designing piping for hazardous materials, one should minimize the inventory in the system. Piping should be large enough to transport the quantity of material required, but not greater. The quantity of materials in pipes can be also minimized by using of material as a gas rather than a liquid. Dow Chemical Exposure Index is a tool to measure inherent safety with regards to potential toxic exposure risks [18]. For example, the risk related to a pipe carrying liquid chlorine from a storage area to a manufacturing building, where chlorine should be vaporized

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and fed to a process, could be decreased by installing the vaporizer in the storage area. This reduces the inventory of chlorine in the pipe by a factor of over ten. Process intensification means using significantly smaller equipment. Examples include novel reactors, intense mixing devices, heat- and mass-transfer designs that provide high surface-area per unit of volume, equipment that performs one or more unit operations, and alternative ways of delivering energy to processing equipment, for example, via ultrasound, microwaves, laser beams, or simple electromagnetic radiation. These technologies can increase the level of physical and chemical processes, allowing high productivity from a small volume of material. A small, highly efficient plant can be supposed to be cheaper and more cost-effective, but also can reduce the magnitude of potential accidents. Safety need not necessarily mean spending money. Safer can also be cheaper, if a small, efficient inherently safer process can be prepared. An example of the effect of a large volume of the reactor is a tragedy in Flixborough (the UK), which occurred in 1974. The accident killed 28 people, and a lot of people suffered burns. The plant was completely destroyed. Technological process included oxygen in the air oxidation of cyclohexane using boric acid as a catalyst to produce caprolactam. In an intermediate formed hydrogen peroxide. The reaction is very slow, so the six reactors were used. Due to the failure of the flange to the pipe a high local concentration of oxygen was created. The cause of the disaster was a broken faucet, and the consequences—the scale of production. The tragedy could have been avoided if the effective mixing of gas and liquid were realized, moreover, that techniques exist for this: feed pump gas into the bottom of the reactor, the use of a cyclone, etc. You can reduce the risk of the process and by its transformation (hybridization). Thus, safer cyclohexane oxidation process was proposed in the year 2004, which comprises adding water to the vapor phase and the use of pure oxygen for the oxidation, which leads to an increased yield and eliminate the side reactions.

3.4.5 Process Intensification as Green Design Concept Scientists predict that the distinguishing feature of the future scientific and technological revolution will be its small volume of resources. For this reason, nanotechnology is an integral structural component of green chemistry. Nanotechnology, as a rule, does not require a large amount of substance to address the challenges it faces. It, first of all, means that the development of technology will not depend on the natural resources of raw materials (oil, gas, and metals), and the ability to use small amounts of the substance. In such circumstances, the economy does not benefit those countries that have large reserves of raw materials, and possibly ahead will be the economy of resource-dependent countries such as China, India, Japan. Korea, etc., In that case, if they are the first to introduce the principles of “green” chemistry for nanotechnology.

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Fig. 3.27 Long pipelines with a plurality of flanges

Minimization and intensification often lead to the simplification of the technological scheme, which is reflected in a decrease in the number of mechanical equipment, connecting nodes, adapters, etc., i.e., anything that can cause operator error or mechanical failure. In particular, we have to avoid long pipelines with a plurality of flanges. It makes sense to use solvent as a medium that absorbs heat for cooling instead of a set of heat exchanger tubes (Fig. 3.27). The substitution of hazardous materials by more benign ones is a core principle of green chemistry, and a key feature in ISD. This, for example, is the replacement of chloroform at supercritical CO2 during decaffeination of coffee beans, replacing phosgene, which is used in the synthesis of isocyanates, urethanes, and carbonates, or dimethyl carbonate to CO2 (Scheme 3.49).

Scheme 3.49 The examples of substitution of hazardous substances for less hazardous ones

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Scheme 3.50 The synthesis of acrylonitrile

The use of less hazardous ingredients at the synthesis of acrylonitrile (Scheme 3.50). Moderation. In many cases, when it is impossible to substitute a hazardous material, the use of less hazardous materials or in less hazardous conditions is preferable. For example, the unpredictable and potentially hazardous Grignard reaction can be moderated using ultrasound to avoid sudden exothermic reactions. Chlorine is frequently stored in pressurized containers, but it is less dangerous to store it in a gas state at low temperatures. Limitation. Limitation is the process of minimizing the effects of failure (of equipment or people) or an incident, by design. One important aspect of the design process should be to limit the available energy to an appropriate level. The Seveso accident in Italy is a real good example. The process involved the production of 2,4,5-trichlorophenol through the base hydrolysis of 1,2,4,5-tetrachlorobenzene. A partially completed batch was shut down at the weekend at a safe temperature of 158 °C, but the vessel was heated with steam from a turbine capable of reaching a temperature of 300 °C. The reactor was only part full and, owing to the high steam temperature, the wall above the reaction liquid reached a much higher temperature. The agitator had been turned off and the high temperature caused a runaway reaction and an explosion involving the formation of carcinogenic 2,3,7,8-tetrachlorodibenzop-dioxin. A wide area of land around the plant became contaminated with dioxins and 2000 people had to receive medical treatment (Scheme 3.51).

Scheme 3.51 Seveso chemistry

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Fig. 3.28 Schematic of a tubular reactor

Reactor design may also have a large influence on tragedy prevention. The tubular reactor or small tubular reactors in series could eliminate the overheating of the reactor (Fig. 3.28). Ethylidene norbornene manufacture involving the use of a hazardous sodium/potassium amalgam in liquid ammonia used such a reactor configuration. Process intensification means using significantly smaller equipment. Examples include novel reactors, intense mixing devices, heat- and mass-transfer designs that provide high surface-area per unit of volume, equipment that performs one or more unit operations, and alternative ways of delivering energy to processing equipment for example, via ultrasound, microwaves, laser beams, or simple electromagnetic radiation [19]. These technologies can increase the rate of physical and chemical processes, allowing high productivity from a small volume of material. A small, highly efficient plant can be expected to be cheaper and more cost-effective, but also can reduce the magnitude of potential accidents. Safety needs not necessarily mean spending money. Safer can also be cheaper, if a small, efficient inherently safer process can be developed. There is a special equipment for process intensification in green chemistry design. The efficient mixing of viscous or nonmiscible liquids or of gases and liquids is a common problem which, if not solved, can lead to mass-transfer-limited reactions with known consequences. Different mixers, for example, radial jet mixer for liquid–liquid effective mixing and reactors of special design are used for the process intensification (Fig. 3.29). Spinning disk reactors have been proposed as an efficient alternative to the stirred batch reactor for fact reactions. It consists of a disc spinning at a speed up to 5000 rpm or more. The reactant liquid is pumped onto the center of the disk, the resulting flow patterns cause intense mixing as the liquids move toward the edge of the disc, where the product is collected. Rotating packed bed consists of a rotating bed containing packing, often metal gauze. This reactor is particularly efficient at gas–liquid mixing, the liquid being fed to the center of the reactor and the gas coming in from the side. Although rotating packed beds provide good mass transfer, heat transfer is not as effective as in the SDR. Catalytic membrane reactors are now being developed in which the reaction and separation are carried out in a single process. It improved yield, selectivity, and increase the overall rate.

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Fig. 3.29 Process-intensified equipment

Fig. 3.30 Membrane equipment

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Membrane processes are used not in the reactors only. The membrane process of pervaporation (separation of liquids by the evaporation through the membrane) can substitute the distillation with water vapor in the processes of the azeotropes separation of such solvents like ethanol, methanol, ethyl acetate, butyl acetate, acetone, etc. (Fig. 3.30).

References 1. Roger AS (2016) Green chemistry and resource efficiency: towards a green economy. Green Chem 11(18):3180–3183 2. Chambers RK, Chaipukdee N, Thaima T, Kanokmedhakul K, Pyne SG (2016) Synthesis of alpha-propargylglycinates using the Borono-Mannich reaction with pinacol allenylboronate and potassium allenyltrifluoroborate. Eur J Org Chem 22:3765–3772 3. Zheng C, Evan SB, Paul TA, Green chemistry in China. Pure Appl Chem 83(7):1379–1390 4. Medina-Gonzalez Y, Camy S, Condoret JS (2014) ScCO2 /green solvents: biphasic promising systems for cleaner chemicals manufacturing. ACS Sustain Chem Eng 2(12):2623–2636 5. Modak A, Bhanja P, Dutta S, Chowdhury B, Bhaumik A (2020) Catalytic reduction of CO2 into fuels and fine chemicals. Green Chem 22(13):4002–4033 6. Tundo P, Musolino M, Aricò F (2017) The reactions of dimethyl carbonate and its derivatives. Green Chem 20:28–85 7. Liu Y, Ren WM, He KK, Lu XB (2014) Crystalline-gradient polycarbonates prepared from enantioselective terpolymerization of meso-epoxides with CO2 . Nature Commun 5:5687 8. Miroslavov G, Gorshkov N, Lumpov A, et al (1999) Proceedings of the fifth international symposium on technetium in chemistry and nuclear medicine, pp 321–324 9. Xing DY, Dong WY, Chung TS (2016) Effects of different ionic liquids as green solvents on the formation and ultrafiltration performance of CA hollow fiber membranes. Ind Eng Chem Res 55(27):7505–7513 10. Fukushima T, Kosaka A, Ishimura Y, Yamamoto T, Takigawa T, Ishii N, Aida T (2003) Molecular ordering of organic molten salts triggered by single-walled carbon nanotubes. Science 300:2072–2074 11. Rauber D, Philippi F, Hempelmann R (2017) Catalyst retention utilizing a novel fluorinated phosphonium ionic liquid in Heck reactions under fluorous biphasic conditions. J Fluor Chem 200:115–122 12. Enrico C, Paolo T, Lorenzo T (2005) Cleaner production and profitability: analysis of 134 industrial pollution prevention (P2) project reports. J Clean Prod 13(6):593–605 13. Philip N (2007) The annotated cat: under the hats of seuss and his cat. Random House, New York 14. Agnieszka G, Zdzislaw M, Jacek N (2013) The 12 principles of green analytical chemistry and the SIGNIFICANCE mnemonic of green analytical practices. Trends Anal Chem 50:78–84 15. Stephen KD, Michael JOC, Lianxi Z, Yuntian TZ, Shaoming H, Jie L (2005) Raman spectral imaging of a carbon nanotube intramolecular junction. Phys Rev Lett 94(1): 16. Trevor K (2000) By accident…a life preventing them in industry. PFV Publications, Peter Varey Associates, London 17. Yang F (2015) Studies on tandem cyclization of alkynones and trifluoromethylation in water at room temperature. Lanzhou University, Lanzhou 18. Zhao YC, Huang S (2017) Recycling technologies and pollution potential for contaminated construction and demolition waste in recycling processes. In: Zhao YC, Huang S (eds) Pollution control and resource recovery, Butterworth-Heinemann, pp 195–331 19. Clark J, Sheldon R, Raston C, Poliakoff M, Leitner W (2014) 15 years of green chemistry. Green Chem 16:18–23

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20. Lancaster M (2002) Green Chemistry: An Introductory text. Royal Society of Chemistry, New York 21. Tanaka K (2003) Solvent-free organic synthesis. Wiley Verlag 22. Rothenberg G (2008) Catalysis: Concepts and Green Applications. Wiley Verlag 23. Adams D, Dyson P, Tavener S (2008) Chemistry in Alternative Reaction Media. Wiley

Chapter 4

Green Chemistry Technology

Abstract A current focus of chemical researches lies in the new activation methods for chemical processes. In particular, the past several decades have witnessed a growing emphasis on ultrasound-, microwave-, and photochemical-assisted reactions that are widely regarded today as green activation methods. Keywords Ultrasound activation · Microwave activation · Photochemical activation

4.1 Ultrasound Activation Ultrasound activation (sonochemistry) is one of the modern methods for the acceleration of chemical processes. Its potential has already been explored long before scientists actually manifested interest in green chemistry. In particular, preliminary studies of chemical changes produced by ultrasound were carried out by Richards and Loomis in 1927, when they discovered the presence of molecular iodine in liquids radiated with ultrasound. Subsequently, in 1933, Boyte noted that nitrogen subjected to ultrasonics in an aqueous solution gives nitrous acid and ammonia. In 1964, Margulis, Sokolskaya, and Elpiner performed sonochemical stereoizomerization of maleic acid and its esters to fumaric acid by the chain mechanism. By now a number of scientific researches on sonolysis have been published. Sound is sonic waves that propagate through a medium and create vibrations in it. Substantially, all sonochemical reactions initiated in the aqueous solutions under the effect of acoustic oscillations are due to the cavitation process [1]. Cavitation—(lat. cavus—hollow)—is the formation of cavities (cavity bubbles, cavity pockets) in a liquid filled either with gas, vapor, or their mixture. Reaching the threshold value during the sonolysis is the required condition for the onset of cavitation. The high threshold power density (over 3 MHz) can conversely hinder the cavitation, which makes some of the reactions impossible. Sound frequency used in sonochemistry can vary from 20 kHz to 2 MHz (Fig. 4.1). Collapsing voids or bubbles release an amount of energy that generates acoustic and shock waves, heats the gas within the collapsing bubbles, emits in the form of light (excitation of luminescence), and forms free radicals. At the point of total © Zhejiang University Press 2021 T. Savitskaya et al., Green Chemistry, https://doi.org/10.1007/978-981-16-3746-9_4

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Fig. 4.1 Sound frequency range

Fig. 4.2 Cavitation processes

collapse, the temperature of the vapor within the bubble may soar up to 5000 °C, and the pressure reaches several hundred atmospheres, which can split chemical bonds (Fig. 4.2). Sonolysis of aqueous solution potentiates otherwise impossible reactions. However, sonication usually has little effect on homogeneous ionic reactions in contrast to its significant impact on redox and radical reactions [2]. The extreme temperature conditions generated by a collapsing bubble can lead to the formation of radical chemical species. Ultrasonic waves in water have been shown to form radicals H• and OH• due to homolytic cleavage. The H• and OH• radicals formed in this reaction are highly reactive and rapidly interact with other radicals or chemical species in the solution. A common product of this reaction in water is hydrogen peroxide (Scheme 4.1). Once formed, radicals can initiate long chains of reactions with other substances in a solution. For instance, iodide can be sonochemically oxidized to triiodide by OH• radicals (Scheme 4.2). The quantity of I3 − can be measured by ultraviolet spectrophotometry at 353 nm. For many years, this so-called Weissler reaction has remained the standard dosimeter for sonochemical reactions.

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Scheme 4.1 The product of homolytic cleavage reaction in water

Scheme 4.2 Long chains of reaction with iodide

In general, ultrasonic waves influence product distribution, reaction mechanism, and rate through temperature increase, facilitate ligand dissociation from metal complexes, accelerate processes at the phase boundary by modifying surface tension, mechanical fragmentation, interface buildup, enhance particle motion, etc. In particular, ultrasound has been widely used for dispergating of solids and cleaning of their surfaces. Being a part of sonoelectrochemistry, it helps to clean and activate electrode surfaces, confers uniform ion transport through an Electrical Double Layer (EDL), prevents electroactive species depletion, reduces the number of bubbles attached to the surface of electrodes. While the sorption processes are often recognized as an integral part of the modern chemical industry, their use is limited either by the holding capacity of sorbing agents or by the slow absorbency rate. A number of studies have also revealed that acoustic oscillation can be used to enhance absorbency rate as well as the sorption capacity. Ultrasound has been commonly used in pharmacy for dissolving, extracting, emulsificating, preparing suspensions, producing microgranules, sterilizing (i.e., in the processes, when it directly interacts with molecules through the liquid phase). A number of antibiotics, such as benzylpenicillin, streptomycin, tetracycline, monomycin, etc., have been observed to boost their antibacterial activity when subjected to ultrasonic waves. Several methods for introducing ultrasound into a reactor have been investigated so far (Fig. 4.3): • Placing a reactor in a water-filled ultrasound exposure tank; • Immersing an ultrasonic source into the reaction medium; • Using a reactor with ultrasonically vibrating walls. There are two main types of ultrasonic transducers that are used in sonochemistry. Magnetostrictive transducers use a property of ferromagnetic materials that causes them to change their shape or dimensions during the process of magnetization (Fig. 4.4). However, frequency constraint (under 100 kHz) and rather low electronic efficiency (60%) are considered to be among the major drawbacks of this device.

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Fig. 4.3 Methods for introducing ultrasound into a reactor

Fig. 4.4 Magnetostrictive transducers

Piezoelectric transducers are used for both the generation and detection of ultrasound employ materials and exhibit the piezoelectric effect, discovered over a century ago (Fig. 4.5). Such transducers are highly efficient (>95%) and, depending on dimensions, can be used over the whole range of ultrasonic frequencies from 20 kHz to many MHz. Fig. 4.5 Piezoelectric transducer

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Homogeneous sonochemical reactions usually proceed via an electron transfer mechanism. A simple example being sucrose splitting which is carried out in an acidic medium using ultrasonic waves with frequencies up to 2 MHz. In this case, the reaction rate is observed to be higher compared to that of the conventional acid hydrolysis under mechanical agitation. This is due to the formic acid formation that occurs when sucrose is oxidized by hydroxyl radicals generated by ultrasound. Benzyl cyanide synthesis presents an interesting example of heterogeneous sonochemistry. It is a useful material for producing phenylacetic acid and its derivatives, paints, fragrances, pesticides, pharmaceuticals; it is also commonly used as a catalyst or as a component of complex catalysts. Benzyl bromide, potassium cyanide, and aluminum oxide mixed in the reaction medium subjected to regular mechanical agitation from ortho-benzyl-toluene and para-benzyl-toluene with a yield of 75%, while the ultrasound-induced synthesis at the frequency of 45 kHz can give a yield of 71% (Scheme 4.3). High temperature and pressure generated by ultrasonic irradiation in parallel with higher cavitational cooling rates can be used for producing amorphous nanoparticles and proved to be a successful alternative for conventional cooling methods. In particular, sonication of aqueous Co2+ and hydrazine resulted in the formation of cobalt nanocluster (Scheme 4.4). Cobalt colloidal nanoclusters primarily consist of cobalt, but they can also comprise a certain amount of oxygen, generally, in the form of a thin oxide layer. Nanoclusters exhibit ferromagnetic properties and can be found in recording, data storage, magneto-optical, and other devices.

Scheme 4.3 Synthesis of benzyl cyanide

Scheme 4.4 Sonication of aqueous Co2+ solution and hydrazine

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4.2 Microwave Activation With all modern technologies associated with the use of microwave radiation comes a long history of its gradual transition from defense industry through consumer electronics finally reaching the science and production sector leaving out other economic fields. Today, microwave enhancement is commonly involved in various industrial processes (e.g., food dehydration, wood desiccation and bonding, manufacturing of porcelain and faience ware, building and construction work, oilfield development, etc.). The properties and uses of microwave radiation have been covered in books, reports, and scientific articles published in Russia and other countries. Numerous international events and conferences on microwave chemistry are held annually. The Journal of Microwave Power and Electromagnetic Energy devotes particular attention to the application niche of microwave radiation. Microwaves are a form of electromagnetic radiation with wavelengths ranging from as long as one meter to as short as one millimeter; with frequencies between 300 MHz (100 cm) and 300 GHz (0.1 cm). This broad definition includes both ultrahigh and radio frequencies. Defining the same frequency range, the term “super high frequency” has gradually been replaced by the term “microwaves”. Within this range, there are four frequencies assigned for industrial applications: 915, 2450, 5800, and 22125 MHz. In most microwave chemistry processes 2450 MHz is utilized as the operating frequency. Microwave-Assisted Organic Synthesis (MAOS) is now regarded as one of the most thriving dimensions. The first scientific researches on microwave radiation as a potential component of organic synthesis were published in 1986. This works encompassed in-depth analysis of Diels–Alder and Claisen reactions, oxidation, and esterification processes. Specifically, the reaction rate was reported to drop 100–1000 times when exposed to microwave energy. It also gave a rise to a completely new method called “MORE Chemistry” (microwave-induced organic reaction enhancement). It has to be taken into account that the household microwave oven is not suitable for laboratory experiments. Special kinds of microwave ovens are used (Fig. 4.6). Microwave radiation triggers certain effects that bring about heat liberation. For instance, the most widely used effect in organic synthesis is dielectric polarization. It is well known that the molecules of polynuclear compounds (including heterocycles) in the electrostatic field tend to stand in such a way so that their dipoles are lined up. The frequency of 2450 MHz radiation is of the same order as the molecular rotation speed. Microwaves can, therefore, induce the rotation of polar molecules. As a result of intermolecular collisions, the substance is heated due to the redistribution of energy, i.e., technically it can be called in situ heating. Unlike during conventional heating, in this case, the heat is generated within the substance and is not transferred by convection from its outer edge, which, in its turn, facilitates a uniform heat distribution, prevents local overheating, and subsequently reduces by-product formation.

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Fig. 4.6 Microwave heating

Thus, unlike low polar compounds (hydrocarbons, CCl4 , CO2 , highly ordered crystalline materials, etc.), polar compounds with a high dielectric permeability (water, ethanol, acetonitrile, etc.) can be effectively heated under microwave irradiation. Microwaves often eliminate solvents, a backflow condenser and make it possible to conduct a reaction in an open vessel. In this case, the temperature of a reaction medium is not limited to the boiling temperature of the solvent, and the reaction occurs much faster. Microwave radiation is absorbed more efficiently in contrast to conventional heating. However, if the reaction mixture has poor absorbing capacity, it can be enhanced by using a well-absorbing solid support (e.g., graphite) or by injecting additives (polar solvents). Sometimes, even if a mixture is exposed to microwave radiation, an additional catalyst may be required. Should that be the case, it is the heterogeneous catalysts that are commonly used for the reactions (e.g., zeolites—for acid catalysis, alkaline, and alkaline-earth catalysts—for base catalysis). The use of homogeneous catalysts is restricted to metal complex catalysis. Another advantage of microwave heating is that microwave energy can be introduced into the reactor remotely so that a source does not interact with chemicals and the introduction of energy can be started and finished immediately. Furthermore, microwave heating often brings additional benefits: • Integration of processes (e.g., dissolution of the reagents and direct energy transfer to the reaction mixture combined); • Carrying out microwave heating under pressure can often homogenize slightly soluble starting compounds into a single phase which is extremely difficult or even impossible with conventional heating; • Ability to monitor and control the main parameters of the reaction (pressure, temperature, time, and power); • Safety; • Ease in checkout and automatic monitoring.

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The use of microwave radiation puts the spotlight on the reaction carried out in superheated water. In this state, the dielectric constant of water ε dramatically drops from 78 at 25 to 20 at 300 °C, while the solubility of organic substances in water significantly increases. Moreover, when heated from 25 to 240 °C, ionicity of water increases by 1000 times. It upgrades to a stronger base and acid; catalytic capacity and reactivity are enhanced. Consequently, various reactions can be conducted in the superheated water that would be impossible under ordinary conditions (hydrolysis, hydration, etc.). One of the examples of its use as the reaction medium for the acid-free Fischer indole synthesis is a reaction of phenylhydrazine and butanone (Scheme 4.5). It is shown that under the microwave irradiation formation of N-arylpyrroles from aniline and γ-diketones takes just a few minutes (Scheme 4.6). Such high-speed processes can be called rapid synthesis. Indeed, the major timeconsuming operation of this synthesis is the reaction work up. The researchers of the LLP “Institute of Organic Synthesis and Coal Chemistry of the Republic of Kazakhstan” discovered a one-step method for the synthesis of the well-known antituberculosis drug “Isoniazid” through the reaction of isonicotinic acid and hydrazine hydrate under microwave irradiation. The process is characterized by fewer stages and its overall intensification (D. P. Khrustalev et al.). It is known that isonicotinic acid hydrazide (INH, 112) cannot be made by reacting isonicotinic acid (111) with hydrazine under convective heating conditions. Convection heating method for INH synthesis includes larger number of stages (Scheme 4.7). The overall equation for microwave-assisted INH synthesis is (Scheme 4.8).

Scheme 4.5 The reaction of phenylhydrazine and butanone

Scheme 4.6 The microwave irradiation formation of N-arylpyrroles

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Scheme 4.7 The reaction of INH synthesis

Scheme 4.8 The equation for microwave-assisted INH synthesis

Thus, the method for microwave-assisted INH synthesis is compliant with the principles of green chemistry. The research team at the Kurnakov Institute of General and Inorganic Chemistry of the Russian Academy of Sciences (IGIC RAS) has designed a microwave-induced method for the synthesis of ferrites, manganites, complex cobaltites, and cuprates compositions from salt mixtures, which significantly reduces the time and energy required for the preparation of the final multicomponent products (A. S. Vanetsev et al.).

4.3 Photochemical Activation Photochemical activation of reactions has been well established and used for a long time. There are a number of photochemical processes that are of the utmost importance for both a biont and the biosphere as a whole. It is primarily regarded as a process of photosynthesis, as well as the synthesis of vitamins, such as vitamin D produced in the human skin, etc. The photochemical decomposition of the silver halides underlies the photo process. There are photochromic materials that are capable of changing color or opacity on exposure to light, which are particularly used either for photochemical recording or for sunglasses manufacturing. Photochemical reactions are also used in the chemical industry. The mechanism of the photochemical processes boils down to the reaction initiated by the absorption of a photon of light by a reactant molecule which entails its excitation. Generally, molecules with an even number of electrons upon photoexcitation initially switch to the excited singlet state (with multiplicity 1). Photochemical reactions usually proceed from the lower excited singlet state or from the triplet state (with multiplicity 3) via intersystem crossing from an excited singlet state (in essence, the spin of the excited electron is reversed) (Fig. 4.7).

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Fig. 4.7 Possible energy levels

A photochemical reaction has three steps: the absorption of light and the transition of a molecule to the excited state; the formation of primary photochemical products following the primary photochemical processes involving excited molecules; secondary reactions of the substances generated during the primary process. Shortlived isomers with increased energy, atoms, and radicals can be found among those primary photochemical products. The photochemical processes can be subdivided into three groups depending on the role and the effect of light [3]. The first group comprises reactions that may occur spontaneously following the light absorption by reagents. For these processes, the light serves as an initiator and as a trigger (typically for the chain exothermic processes). Among these are, for example, chlorination and bromination of hydrocarbons, synthesis of some of the polymers. The second group of photochemical processes embraces processes that are necessary for a continuous photoenergy supply to the reactants. When the light is removed, processes stop. The most well-known example of this type of process is photosynthesis. The third group includes the reactions in which special photosensitizers are introduced into the reaction medium to enhance photochemical efficiency. While the molecules of these substances can be excited by the absorption of light quanta, they are not involved in the subsequent chemical reactions. Thus, they can be regarded as a sort of “catalysts” for photochemical reactions. Sensitizers are usually required when light-absorption energy from a molecule does not cover the energy demand for the formation of the active complex. The photosensitizer should, therefore, absorb the light of a different and more convenient wavelength for this reaction. The best-known photosensitizer is chlorophyll. It plays a key role in photosynthesis as it absorbs photons of the red light during the light phase and transmits excitation through a number of carrying agents to the water molecules during the dark phase. Thus, in the classification, the process of photosynthesis can be attributed simultaneously to two groups of photochemical processes.

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Fig. 4.8 Energy profiles of the reactions

The feasibility and the wide use of photochemical processes are down to the fact that they show a number of advantages over the thermal processes, namely: • reduction of the use of reagents (photons manifest themselves as the ideal reagents by prompting the reaction and disappearing with no apparent direct pollution); • low-temperature dependence; • ability to control the rate of reaction; • high degree of purity of the product; • high selectivity and control of the selectivity level. The latter fact is demonstrated dramatically in Fig. 4.8 that exhibits the energy profiles of the photochemical and thermal reactions. The bottom line indicates the most probable path of the thermal reaction, which leads to the formation of product 1 and has the lowest activation energy. For product 2, it is necessary to spend more energy which is relatively easy to implement using photochemical activation. The dashed line indicates the path of a photochemical reaction that leads to the formation of product 2. Here are three of the most well-known examples of photochemical reactions implemented commercially. (1)

(2)

The photochemical nitrosation of cyclohexane (PNC-process) for caprolactam synthesis. Full Production Scale reaches 150 000 tons per year. For example, the “Toyo Rayon” plant in Nagoya (Japan) has a complete set of equipment for the PNC-process (Scheme 4.9). Photo-bromination of diethyl carbonate. Full Production Scale is 150 tons per year. Basically, the process is carried out by the Swedish pharmaceutical company AstraAB, which merged with Zeneca Group plc into AstraZeneca in 1999. Today it is the largest Anglo-Swedish company in the world (Scheme 4.10).

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Scheme 4.9 The photochemical nitrosation of cyclohexane for caprolactam synthesis

Scheme 4.10 Photo-bromination of diethyl carbonate

(3)

Production of vitamin D2 and D3 by preliminary conversion of provitamin D to previtamin D. The process is implemented by several companies (Scheme 4.11).

Provitamin D

Previtamin D

Vitamin D2: R=C9H17 Vitamin D3: R=C8H17 Scheme 4.11 Production of vitamin D2 and D3 by preliminary conversion of provitamin D to previtamin D

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Photochemical reactions are important for pharmaceuticals primarily, due to the fact that light can cause degradation (photolysis) of many drugs. Many other substances and materials, such as wood, paper, paint, plastics, etc., can be decomposed when exposed to light. Of course, manufacturers and consumers should be sensible of this fact.

4.4 Conclusion The goal of the current lecture course on green chemistry is to show the new activation methods for chemical processes, such as ultrasound-, microwave-, and photochemical-assisted reactions that are widely regarded today as green activation methods. The main objectives of the course are the following: (1) (2)

To introduce the definition of each method, special devices, and main uses; To give the most well-known examples of each reaction implemented commercially.

References 1. Kuznetsov DV, Raev V, Kuranoc G, Arapov OV (2005) Microwave activation in organic synthesis. Russ J Org Chem 41(12):1719–1749 2. Fatma AB, Sherifa MA, Mohamed AR (2012) Evolution of microwave irradiation and its application in green chemistry and biosciences. Res Chem Intermediat 38(2):283–322 3. Kappe CO, Dallinger D, Murphree SS, Microwave synthesis-an introduction. Practical Microwave Synthesis for Organic Chemists: Strategies, Instruments, and Protocols, pp 1–9 4. Clark J, Masquarrie D (2002) Handbook of green chemistry and technology. Blackwell 5. Vanetsev AS, Tretyakov YD (2007) Microvawe-assisted synthesis of individual and multicomponent oxides. Russ Chem Rev 76(5): 397-413 6. Khrustalev DP, Khamzina GT, Fazylov SD, Muldakhmetov ZM (2010) A method of producing isoniazid under microwave irradiation. Innovative patent of the Republic of Kazakhstan No. 22270

Chapter 5

Green Chemistry and Sustainable Development

Abstract Based on the principles of sustainable development, this chapter discusses the relationship between sustainable development and environmental protection, and analyzes environmental problems which influence sustainable development in Belarus and in China. In order to eliminate those restrictive factors of sustainable development, the following environmental strategies should be taken for the ecological management system and ecolabel system. Keywords Sustainable development · Ecological management system · Ecolabel system

5.1 Sustainable Development (SD) Strategy Genesis and Evolution In the foreseeable future, human capability to fit into the biosphere and the ability to determine whether its activities commensurate with the natural complex will be the major criteria for assessing the success of humankind. That is why scientists stress the importance of development without destruction, and the term sustainable development becomes well established in the modern language. The World Conservation Strategy, produced in 1980, was the first document to enunciate and define the concept of “sustainable development”, which was later expanded by the World Commission on Environment and Development Report, byname Our Common Future (the Brundtland Commission headed by Gro Harlem Brundtland, former Prime Minister of Norway) in 1987 [1]. The document represents an idea that sustainable development calls for a convergence between the three pillars: humans, society, and environment. From there, humanity should keep within its means, maintain sustainable resource use, and finance the programs aimed at preventing the dire consequences. The term sustainable development originated in Our Common Future was further popularized at the United Nations Conference on Environment and Development, held in Rio de Janeiro, Brazil, in 1992. The report included a definition of sustainable development: “development which meets the needs of the present without compromising the ability of future generations to meet their own needs.” (Fig. 5.1). © Zhejiang University Press 2021 T. Savitskaya et al., Green Chemistry, https://doi.org/10.1007/978-981-16-3746-9_5

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Fig. 5.1 United Nations launches global dialogue on sustainable development

The widely accepted idea behind the term sustainable development doesn’t, however, give a clarifying interpretation of its notion, as it runs the gamut of meanings, including “defendable, defensible”, “justifiable”, “maintainable”, and “supportable”. These connotations illustrate the essence of the notion that inherently tends to balance between economic progress and protection of the environment [2]. There is no fixed, commonly accepted definition of sustainable development; the attitude to sustainable development also varies. It’s a multidimensional model encompassing various definitions, including the following: “sustainable development—is the development based on a balanced consideration of the needs of people and the environment, which allows us to meet the needs and aspirations of both present and future generations. It limits economic growth and social development to within nature’s resource limits and capacity for self -regeneration.” At the United Nations Conference on Environment and Development (UNCED) held in Rio de Janerio, one of the key documents of our times, Agenda 21, a comprehensive plan of action toward sustainable development, was adopted by more than 178 Governments. It offers policies and programs to achieve a sustainable balance of society within social, economic, and environmental spheres. Thereby, three aims of sustainable development can be distinguished: (1) (2) (3)

Ecological (maintenance of environmental integrity, conservation of biodiversity, and biosphere at large); Economic (economic growth and effectivization); Social (improvement of living conditions, constitutional evolution, realization of social equity).

Practice proved the ecological constituent to be an integral part of human involvement. In accordance with these three aims [3], a triple bottom line concept of sustainable development (an accounting framework with three parts: social, environmental (or ecological), and financial, abbreviated as “3P”) has been coined (Fig. 5.2).

5.1 Sustainable Development (SD) Strategy Genesis and Evolution

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Fig. 5.2 Triple bottom line concept

The implementation of sustainable development concept is partially based on the identification of its measurable indicators. Both international organizations and the scientific community are operating in this direction. Proceeding from the aforementioned triad, there should be three groups of factors, representing ecological, economic, and social aspects. Thus far, the following criteria were accepted as the system-wide indicators: (1) (2) (3)

Integral sustainable development index based on Human Development Index (HDI); Per capita Gross Domestic Product (GDP) level; Ratio of anthropogenic load on the environment;

Three aspects of sustainable development are also reflected in the IPAT equation [4], which is a simple conceptual expression of the human impacts on the environment (Fig. 5.3). The first variable P represents the population of an area, such as the world. The variable A stands for affluence and represents the average consumption of each person in the population (per capita GDP). The third variable T represents the ecological consistency of the applied technologies. Scientists pin their hopes on this particular variable as it can help to reduce industry resource intensiveness and man-made impact on the environment as well as switch to environmentally determined development. Fig. 5.3 The IPAT equation

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5.2 National SD Strategy in Belarus and in China In 2002, the World Summit in Johannesburg set a challenge to develop partnership initiatives covering all public sector entities and to assume a collective responsibility to advance and strengthen the interdependent pillars of sustainable development— economic development, social development, and environmental protection—at the local, national, and global levels. State governments, in accordance with Agenda 21, are strongly urged to adopt national strategies for sustainable development. The national strategy represents essential steps taken by the government on the pathway to achieving the sustainable development ideal. Belarus was among the CIS pioneer states to work out the National Sustainable Development Strategy (NSDS)—2010 approved by the government in 1997 and to establish national authorities to monitor its implementation. Today’s agenda includes the National Strategy on Sustainable Social and Economic Development of Belarus for the Period till 2020, meeting current trends and social interrelations. NSDS-2020 was elaborated pursuant to the Law “On State Forecasting and Socio-Economic Development Programs of the Republic of Belarus,” United Nations Millennium Declaration, signed in September 2000, the Johannesburg Declaration on Sustainable Development, signed at the World Summit on Sustainable Development in Johannesburg in 2002. NSDS till 2035 is under discussion. Environmental conservation and resource management meeting requirements of the present and future generations top NSDS-2020s priority list. The implementation of the strategy can be performed in several ways, based on integrated social, economic, and ecological development aspects. Ecological policy covering the period to 2020 primarily focuses on the following issues: (1) (2) (3)

(4)

(5) (6)

(7) (8) (9)

Economy ecologization; Developing legislation on environmental resources management; Wise nature use implying gradual transition from extensive natural resources utilization to minimization of consumption of nonrenewable resources and no consumptive use of renewable ones; Resources-saving, low- and zero-waste technologies facilitation; production modernization, new technologies and methods for natural resources restoration; wider use of secondary resources, safe waste disposal; Gradual transition toward international technology and manufacturing standards; Reduction of human-induced environmental impact; rehabilitation of ecosystems degraded due to mining (especially oil, potash salt, building stone, dolomite, clay, etc.); Building an optimal system of designated conservation area and wetlands; conservation biology; Economic valuation of environmental assets; natural resource damage assessment; Basic and applied ecological research;

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(10) (11) (12)

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Mitigating negative implications of radioactive contamination; Expansion of international cooperation in ecology and natural resource management; Ecological education, training; environmental public awareness.

Protection and wise use of natural resources. In order to ensure sustainable development of the state, integrated environmental control must be exercised over the rational use of biosphere potential and conservation of biodiversity. Safe biotechnology and biosecurity. The dawn of the twentieth century saw the torrid growth of biotechnologies based on molecular and genetic advances. In view of the fact that biotechnologies figure big in the sustainable development of Belarus, the government has an increased focus on this issue. Therefore, a number of national technological programs have been set up, that are currently being implemented. Safer toxic agents use. Industrial and household waste management. Wide use of chemicals for industrial and household purposes scales up the risk of adverse environmental and human health impacts. In that context, new strategies for industrial and household waste management are being elaborated and implemented. They help to offset negative environmental impacts and prevent detrimental human health effects. The harmonization of national environmental legislation with relevant international law. Improvement of national environmental legislation and its harmonization with international environmental standards play a key role when shaping and implementing National Strategy for Sustainable Development—2020. Belarus has already acceded to the major environmental conventions and UN protocols, a number of European and CIS agreements; it also has signed bilateral treaties on transboundary resources management with several contiguous states. China, as the largest developing country in the world, has always given top priority to development. China was one of the first countries to formulate and implement the sustainable development strategy. The Chinese government defined environmental protection as a basic national policy in 1982 and signed the “Rio Declaration on Environment and Development” [5] and the “Agenda 21” in 1992. In 1994, the Chinese Government published China’s Agenda 21— White Paper on China’s Population, Environment, and Development in the 21st Century [6]. Under the 9th Five-Year Plan (1996–2000), the concept of sustainable development as a major strategy for China to push forward its modernization program. China’s Agenda 21 clarifies China’s sustainable development strategies and policies [7]. Its 20 chapters can be divided into 4 major sections: (1) overall strategies for sustainable development; (2) aspects of the sustainable development of society;

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(3) sustainable development of the economy; and (4) Protection of resources and the environment. Each chapter has been organized into two sections [7]: introduction and program areas. The introduction clarifies the objectives and significance of each program area and the role each plays in overall sustainable development; each particular program area is then subdivided into three subsections: basis for action and key problems in the first, the objectives for solving these problems in the second and proposed actions for implementation in the last. By following the goals of Agenda 21 the Chinese government clearly states that it must do this at the same time as it is improving economic conditions and structures, enhancing their effectiveness, and maintaining an annual average GNP (Global National Product) growth rate of between 8 and 9%. One special feature for China to implement the strategy of sustainable development is to conduct pilot and demonstration programs on a local level. In 1997, 16 provinces and municipalities (including Beijing and Hubei) were selected as pilot local agenda areas to build local capacities for the national sustainable development strategy [8]. By the end of 2001, 25 provinces, municipalities, and autonomous regions as well as many localities had set up special offices for implementing their individual Local Agenda 21 programs. The nine priority areas were as follows: Capacity Building for Sustainable Development; Sustainable Agriculture: Cleaner Production and Environmental Protection Industry: Clear Energy and Transportation; Conservation and Sustainable Utilization of Natural Resource; Environmental Pollution Control; Combating Poverty and Regional Development; Population, Health and Human Settlements; and Global Change and Biodiversity Conservation [9]. After the 2008 global financial crisis, China presented the green and low-carbon development in its outline of the 12th Five-Year Plan for National Economic and Social Development in 2011. During the “12th Five-Year Plan” period, the Chinese government proposes that changing the pattern of economic development should be the primary line of work, adding the share of nonfossil fuel as a binding target, presenting such new policies as rational control of total energy consumption, gradually establishing carbon emission trading market, etc., in order to promote China’s green and low-carbon development and transformation, thus opening-up a sustainable development road with Chinese characteristics in terms of both idea and practice [10]. The 13th Five-Year Plan was reviewed and approved by the Fourth Session of the 12th National People’s Congress in March 2016, defining the development concept featuring innovative, coordinated, green, open, and shared development [11]. In the coming years, China will pursue green development by promoting a green and lowcarbon development model and lifestyle, protecting the ecological system. It will make great efforts to deepen opening-up, thus realizing win-win cooperation.

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5.3 Development of Ecological Policy and Natural Resource Economics United Nations Sustainable Development Summit held in September 2015 adopted the 2030 Agenda for Sustainable Development, which provides guidance to national development and international development cooperation in the next 15 years, marking a milestone in the global development process [12]. Implementation of the 2030 Agenda for Sustainable Development is the joint task of all countries: Transforming our world. Countries should be encouraged to formulate their domestic development strategies and take measures to implement the 2030 Agenda in accordance with national conditions and respective characteristics, while the means of implementation should be allowed to be differentiated, due to diversified national conditions and respective capabilities. Seventeen Sustainable Development Goals and 169 targets demonstrate the scale and ambition of this new universal Agenda. Sustainable Development Goals: (1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13) (14) (15)

(16)

Goal 1. End poverty in all its forms everywhere; Goal 2. End hunger, achieve food security and improved nutrition and promote sustainable agriculture; Goal 3. Ensure healthy lives and promote well-being for all at all ages; Goal 4. Ensure inclusive and equitable quality education and promote lifelong learning opportunities for all; Goal 5. Achieve gender equality and empower all women and girls; Goal 6. Ensure availability and sustainable management of water and sanitation for all; Goal 7. Ensure access to affordable, reliable, sustainable and modern energy for all; Goal 8. Promote sustained, inclusive and sustainable economic growth, full and productive employment and decent work for all; Goal 9. Build resilient infrastructure, promote inclusive and sustainable industrialization and foster innovation; Goal 10. Reduce inequality within and among countries; Goal 11. Make cities and human settlements inclusive, safe, resilient and sustainable; Goal 12. Ensure sustainable consumption and production patterns; Goal 13. Take urgent action to combat climate change and its impacts*; Goal 14. Conserve and sustainably use the oceans, seas and marine resources for sustainable development; Goal 15. Protect, restore and promote sustainable use of terrestrial ecosystems, sustainably manage forests, combat desertification, and halt and reverse land degradation and halt biodiversity loss; Goal 16. Promote peaceful and inclusive societies for sustainable development, provide access to justice for all and build effective, accountable and inclusive institutions at all levels;

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Goal 17. Strengthen the means of implementation and revitalize the global partnership for sustainable development. * Acknowledging that the United Nations Framework Convention on Climate Change is the primary international, intergovernmental forum for negotiating the global response to climate change.

The Agenda reaffirms all the principles of the Rio Declaration on Environment and Development, including the issues of raw materials, water, energy, and environmental capacity. Raw materials. It was not until the end of the twentieth century that petroleum products ceased to be critical raw materials. Renewable biotech-based feedstocks are expected to assume significance over the next years. By 2020, the use of renewable materials will reach an estimated 25%, oil— 75%; 50%–50%—by 2040 and by 2050 renewable resources will run up to 75% (Fig. 5.4). However, the story is not complete, because of the fact that Russian scientists discovered the oil at the age of fifty that can be tolerated as evidence of its renewability. Water. There are different approaches to estimate the amount of so-called stable water. They are somewhat arbitrary and are usually the subject of controversy. In all circumstances, the major challenge for the world community is to preserve biosphere and, which is more, the world aquatic resources, especially freshwater ones, representing the most essential part of the biosphere.

Fig. 5.4 Use of renewable resources

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Fig. 5.5 Primary energy source balance

Energy. According to the Russian National Research Centre “Kurchatov Institute” forecast, by mid-century, the growth of primary energy demand will make up: coal—4 times increase, biomass and wastes, hydroelectricity, wind and solar energy, nuclear energy—3, 2, 9, and 3 times increase, respectively (Fig. 5.5). However, population growth will make the need for energy sources yet more pressing. As such, there is a strong need to promote all energy sources available. Moreover, the world must switch over from nonrenewable sources to green energy, such as wind, solar energy, etc. In so doing, at the Rio + 20 Conference, took place in Rio de Janeiro, Brazil in June 2012—the participants stressed the need for technological innovations, especially in the energy industry, as an integral part of the sustainable development of society, and also laid down the technology requirements. Curiously enough, nuclear industry conditionally meets these requirements, since: (1) (2) (3)

It has an inexhaustible resource base; Under normal operating conditions, it poses no hazard to the environment; Although modern technologies do not provide a means of deactivation and disposal of nuclear waste from the Nuclear Fuel Cycle (NFC), the nuclear industry guarantees escape proof, and environmentally friendly nuclear-waste storage.

Environmental capacity. In this particular case, the reduction of waste released into the environment and transition to Zero Waste strategy are seen as one of the key tasks. The idea of Zero Waste strategy seems absurd on the face of it. For where there is light there will always be shadow, every useful material must have its contrary—useless waste. However, two new opinions have brought a completely

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Fig. 5.6 Key sustainable development strategies

new perspective on the waste issue. The first, long-established opinion says: “If it’s useful, then keep it.” This one implies waste can be used in different ways. The second, more recent one is of ecological nature. According to it, good waste is a recyclable one. The term zero waste owes its origin to the industry. The concept has gained currency in the past few decades in response to the Japanese system of Total Quality Management (TQM). Initially, this concept was primarily based on zero defects idea. This envisages the development of methods for manufacturers, which effectively eliminate production fault. This concept has been successfully used by such manufacturers as Toshiba. In the past 10 years, Honda (Canada) has reduced the amount of production waste by 98%. Zero waste concept has of late years reached at the municipal level. Thus, new world outlook and values (e.g., green chemistry), as well as renewable resources, sustainable water, and energy use, will make for the formation of a sustainable society (Fig. 5.6). Moreover, it should be pointed out that sustainable development concept at present matches not so much the criteria of Back to the Nature concept upheld by the number of environmental groups as the criteria of Back to the Future, since the latter combines environmental friendliness along with smart use of eco-friendly green technologies.

5.4 Ecological Management System (EMS) Because the majority of world manufacturers aim to go global, it’s necessary for them to use international environmental management instruments. Since the early 80s, leading companies have thereby introduced environmental management system as an element of enterprise management. In general, EMS emerged in the 1990s within the sustainable development concept. Consequently, a new British Standard BS 7750

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“Specification for Environmental Management Systems” was elaborated in 1992. In 1993, the Eco-Management and Audit Scheme (EMAS) was adopted. In view of growing public interest in environmental management issues and in order to ensure unity of methods, international standards were established. The first ISO 14001 and 14004 standards were promulgated by International Organization for Standardization in 1996. Subsequently, ISO 14000 standards complex was further expanded, while ISO 14001 remained a core document comprising both general requirements and guidelines for environmental management. Environmental management, aimed at environmental control and reduction of negative impact on the environment, is now exercised at the national, regional, and global levels. According to ISO 14001, EMS refers to the management of an organization’s environmental programs, which includes the organizational structure, planning, responsibility, and resources for developing, implementing, and maintaining policy for environmental protection. An EMS follows a Plan-Do-CheckAct (PDCA) or Deming cycle (the USA, 1950): (1) (2) (3) (4)

PLAN—map out activity in accordance with the adopted policy; DO—implement the plan, execute the process, make the product; CHECK—monitor activity; ACTION—determine and apply changes that will include improvement of the process or product.

From there, EMS poses a dynamic cyclic process (Fig. 5.7). Environmental policy is of prime importance when introducing environmental management system. It is used by an organization to announce intentions and principles associated with overall eco-efficiency, which casts the foundation for further actions and identification of planned ecological targets. Environmental policy must meet the following criteria: (1)

It must be appropriate to the magnitude of the problem and must commensurate with any environmental impact encountered;

Fig. 5.7 Key EMS elements

Set policy

Peview

Planning Continuous improvement

Audit & Corrective action

Implementation

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(2)

Preventive actions (along with overall advancement efforts) must be taken to eliminate the potential of environmental pollution; It must comply with current environmental legislation; All data must be publicly available;

(3) (4)

Although formerly regarded by companies as a rather venturesome enterprise and extra burden, when the company could possibly face administrative penalties and environmental costs, if it refused to introduce the system, today, EMS is a chance to enter into new markets, render high-cost, lucrative services, improve image, and increase revenue. Environmental audit is one of the established instruments of environmental management. It is a monitoring mechanism for drafting development recommendations and assessing compliance of economic entities with the requirements, including international environmental standards and regulations, in a comprehensive, independent, and documented manner. The master documents that define eco-audit procedures are ISO 19011 and 14015. Eco-audit aims to: (1) (2)

Provide relevant information on environmental performance indicators and reveal whether an organization fails to comply with a standard. Elaborate recommendations to enhance the effectiveness of an existing EMS program, or to improve environmental protection practices and processes.

Eco-audit can be commissioned by the supervisory bodies, government institutions, industrialists, investors, insurance companies, and intending purchaser. According to EMAS applied to the EU states, environmental audits, covering all activities at the organization concerned, must be conducted within an audit cycle of no longer than three years. As for EMS, the cycle time is not specified. In any case, companies must conform to the requirements of ISO 14001 (EMS) to use EMAS. At present, enterprises that enjoy access to global markets must conduct eco-audit as an essential prerequisite for environmental certification of the product. Environmental certification is a type of certification that confirms compliance of economic and other activities of enterprises with applicable technical and environmental regulations. It can be applied to manufactured articles, production process, wastes, and EMS itself. Today, more than 90000 enterprises worldwide are certified according to ISO 14001 standards, of which 18000 are in Japan, over 8000—in China, over 6000—in Spain. In Belarus, environmental certification is currently functioning in its initial stage. At the same time, the accumulated experience testifies to intensified activity in this sphere. In Belarus, there are 320 certified enterprises, of which 303 received National Certificates and 17—International Certificates as of 31.12.2012.

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5.5 Ecolabel System The environmental policy instrument that focuses on the development of the market and aims to promote the development of ecologically advanced products is ecolabeling. Ecolabel is information about the relative environmental quality of a product, process, or service presented in the form of text, graphical, and colored symbols or any combinations thereof. Ecolabel may also include additional information regarding: (1) (2) (3)

General ecological properties of products that reflect total product life cycle; Specific ecological properties of products, e.g., signs that indicate the absence of hazardous substances; Identification of natural foods.

Ecolabeling aims to: (1) (2) (3) (4)

provide consumers with information on ecological properties and quality of products; build and cultivate customer trust in such products; expand its market presence and make profit; enhance ecological properties of a product. The following requirements must be met for ecolabeling to be applied to products:

(1) (2) (3)

The use of heavy metals, bromine-, chlorine-containing substances, flammable substances, and freons is restricted; An item must be utilizable; Manufacturer must pursue ecological policy adjusted for importing countries’ standards.

There are various types of ecolabels for packaging materials, electronics, household appliances, green products, food, and cosmetics. Electronics and Appliances labeling was introduced by TCO (Swedish Confederation of Professional Employees), the Swedish Society for Nature Conservation, and the Swedish Energy Agency. Ecolabel ensures that goods and services comply with the highest ecological standards allowing for the life cycle and are eco- and human-friendly.

Food labeling includes information on natural produce grown without the chemical pesticides and fertilizers, with no added color or synthetic ingredients.

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Cosmetics labeling. Introduced by British Union (BUAV) in 1998, the internationally acclaimed Humane Cosmetics Standard puts consumers in the picture of cosmetics that haven’t been tested on animals marked with “Animal friendly” or “Not tested on animals” signs. Package labeling issue is worth dwelling on because it is necessary to be aware of basic ecolabel symbols one may find on most packaged products and goods. Some of these ecolabels testify that the recovery of such packaging materials is safe for the environment. The second urge consumers not to litter, but to instead recycle and support the environmental initiative. The third warns of the ingredients and materials that are environmentally hostile or vice versa, indicate the absence of ozone-depleting substances in the product. Companies are only eligible to use ecolabel if they pass the examination and prove environmental safety and high quality of their production. The Green Dot (Der GrünePunkt). The black and white, green and white or simply green symbol indicates that the manufacturer of the product has contributed to its recovery and recycling in Germany. These three arrows moving in a triangle represent a complete cycle (manufacturing–usage–recycling). The symbol indicates generic recyclable materials. Little numbers inside of the chasing arrows specify the type of material (1–19—plastics, 20–39— paper, 40–49—metals, 50–58—wood, 60–69—fabrics, and 70– 79—glass) and are often used with an acronym representing the plastic below the triangle. This code simplifies the process of sorting and recycling of materials. Here, 1 is for polyethylene terephthalate (PET), 2—high-density polyethylene (HDPE), 3— polyvinyl chloride (PVC), 4—low-density polyethylene (LDPE), 5—polypropylene (PP),and 6—polystyrene (PS). The international symbol for “food safe” material is a wine glass and a fork symbol. The symbol identifies that the material used in the product is safe for food contact. This symbol implies that the package should be thrown into the waste bin. The image is often accompanied with the slogans “Keep it tidy” or “Thank you”.

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This symbol is known as the “Crossed out Wheelie Bin Symbol.” When this symbol is marked on a product or packaging, it means that the product, e.g., electronic equipment (battery, accumulator) containing hazardous substances, such as mercury, cadmium, or lead, should not be disposed of with your general household waste. Instead, it is your responsibility to dispose of waste equipment by handing it over to a designated collection point for the recycling of waste electrical and electronic equipment. Manufacturers usually put this symbol on the packaging made of recycled or recyclable materials. Manufacturers are also recommended to determine the exact percentage of recycled material used in the product by printing an inscription on its packaging, e.g., “This product comprises around 95% recycled paper and cardboard.” For instance, some German goods are marked with the following inscription: “Flachgelegtgehoreichzum Altpapier, Danke,” which literally means: “Fold me flat and I’ll become recovered paper. Thank you.” In Belarus and Russia national eco-labels still refer to the quality of the product and not to its packaging’s characteristics. This picture posturizes the first Russian ecolabel. Developed in Saint-Petersburg in the year 2001, Vitality leaf is a mark that attests to the quality of the product. Russia still needs to join the Global Ecolabeling Network (GEN) and its ecological legislation to be acknowledged by the European community in order for the label to meet the requirements of the EU. The Technical Code of common practice, TC 126-2008 worked out by the Belarusian State Institute for Standardization and Certification commissioned by the Council of Ministers was enacted in Belarus on June 1, 2008. Since the code came into force, domestic producers and importers have been at liberty to voluntarily mark food products with a Natural Product label.

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China Environmental Label was initiated by SEPA (State Environmental Protection Administration, now it is the Ministry of Environmental Protection of China—MEP) in 1993. It provides environmental standards for construction materials, textiles, vehicles, cosmetics, electronics, packaging, and more. This government-run eco-label (the Ten Circle Mark) is issued by the China Environmental United Certification Center under the jurisdiction of the SEPA. The logo, chosen through a public design contest, means “joint effort of the nation to protect the environment on which human beings rely.” China environmental labeling program is a public voluntary ecolabel scheme, aiming to encourage businesses to rationally use resources and energy to develop and produce environment-friendly products, guide the consumers to choose and identify green products toward sustainable consumption, and provides a way for the businesses and public to self-consciously participate in environmental protection. This is an organic food and product label whose mission is to promote the development of organic agriculture and food in China. The characteristics of the standard(s) related to this ecolabel are: applicable life cycle and supply chain phases, social and environmental attributes, mutual recognition with other ecolabels, and standard details, including standard document, review frequency.

5.6 Conclusion In order to eliminate those restrictive factors of sustainable development, the following environmental strategies should be taken: (1) (2) (3) (4)

Speeding up technological revolution and optimizing industrial structure; Protecting living beings resources; Strengthening public environmental consciousness; Protecting the environment in accordance with laws.

References

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References 1. Enrico C, Paolo T, Lorenzo T (2005) Cleaner production and profitability: analysis of 134 industrial pollution prevention (P2) project reports. J Clean Prod 13(6):593–605 2. Philip N (2007) The annotated cat: under the hats of seuss and his cat. Random House, New York 3. Agnieszka G, Zdzislaw M, Jacek N (2013) The 12 principles of green analytical chemistry and the SIGNIFICANCE mnemonic of green analytical practices. Trends Anal Chem 50:78–84 4. Stephen KD, Michael JOC, Lianxi Z, Yuntian TZ, Shaoming H, Jie L (2005) Raman spectral imaging of a carbon nanotube intramolecular junction. Phys Rev Lett 94(1): 5. Trevor K (2000) By accident…a life preventing them in industry. PFV Publications, Peter Varey Associates, London 6. China’s agenda 21: white paper on China’s population, environment and development in the 21st century. China Popul Today 11(4):5–8 (1994) 7. China’s agenda 21. Appl Geograp 16(2):97–107 (1996) 8. Lo AY, Cong R (2017) After CDM: domestic carbon offsetting in China. J Clean Prod 141:1391– 1399 9. Zhang J, Zhang, L (2016) Impacts on CO2 emission allowance prices in China: a quantile regression analysis of the Shanghai emission trading. Scheme Sustain 8:1–12 10. Wei Q, Tian MM (2013) Building carbon emissions trading system for China under the experience of EU emissions trading system. In: Proceedings of the applied mechanics and materials, 2nd international conference on information technology and management innovation, Zhuhai, China 11. Tang L, Wu JQ, Yu L (2017) Carbon allowance auction design of China’s emissions trading scheme: a multi-agent-based approach. Energy Policy 102:30–40 12. Liu CM, Wang XH, Duan MS (2012) Research on MRV establishing in future emissions trading scheme in China based on analysis on MRV of overseas representative ETs. In: Proceedings of the natural resources and sustainable development, 1st international conference on energy and environmental protection (ICEEP 2012) 13. Clark J, Masquarrie D (2002) Handbook of green chemistry and technology. Blackwell

Chapter 6

Renewable Sources of Raw Material and Energy

Abstract Twenty principles of “green” chemistry mean that it efficiently uses inputs, i.e., raw materials which are mostly renewable, reduces the amount of waste, avoids the use of toxic and/or dangerous reagents and solvents in the production and consumption of chemical products. Specifically, Principle 7 formulates the requirements for raw materials: raw materials for the production of the product must be renewable, not exhaustible, if it is economically feasible and technologically possible. The notion of “raw materials” in this case should include not only the raw materials themselves, but also the energy consumption in the process of obtaining the final product, which leads to the production of waste such as carbon dioxide with all the ensuing consequences. Keywords Renewable energy source · Biomass · Chemical synthesis

6.1 Renewable Energy Sources The strategy of switching to renewable (vegetable, natural) raw materials is relevant in view of the fact that by the end of the twenty-first century, the exhaustion of oil and gas reserves is depletion projected, and in a few more years the situation with coal will be the same [1]. As for oil, exhaustion threatens the reserves that are easily extracted, i.e., cheap oil. The future development of oil reserves will require additional funds which will rise its cost. In addition, Russian scientists have found the youngest oil on the planet. Its age is about 50 years. This was determined by Russian and Swiss researchers using the method of radiocarbon dating. This oil was found in the caldera of the Uzon volcano. It was synthesized by thermophilic bacteria by anaerobic synthesis on the surface of thermal springs. In the caldera of the volcano, like in a natural reactor, the bacteria implemented the synthesis, the main stages of which were the synthesis of carbon dioxide, lipids, and, finally, hydrocarbons. Thus, if a few years ago it seemed that there was a very clear line between what to consider as renewable or nonrenewable raw materials, but now it has begun to wear off. Renewable sources of energy include: water (tides, waves, and rivers), geothermal sources extracted from underground natural medium, land, water, air, biomass, which © Zhejiang University Press 2021 T. Savitskaya et al., Green Chemistry, https://doi.org/10.1007/978-981-16-3746-9_6

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consists of plants grown to obtain renewable energy sources (also includes trees and waste of consumption and production), biogas, which is given off by in landfills. The potential of renewable energy sources is too great to ignore. For example, the daily amount of sunlight that can be converted into electricity is 20 times greater than the annual electricity consumption by the planet’s population.

6.2 Biomass as a Source of Raw Materials for Chemical Synthesis “Green” chemistry suggests using biomass as a renewable source of raw materials and energy. Biomass is the aggregate mass of plant and animal organisms present in the biogeocoenosis at the time of observation. In the encyclopedia, biomass is defined as any nonfossil material of biological origin. Approximately, the total biomass of the Earth is estimated at 2.4 × 1012 tons. Annually on Earth about 170 billion tons of primary biomass is formed and approximately the same volume is destroyed [2]. Biological substances of plant origin accumulate energy, extracting it from solar radiation. This complex process of converting solar energy, as a result of which glucose is obtained, is called photosynthesis. Biochemical conversion of biomass can yield a number of substances that are very important for the chemical industry, but from the point of view of obtaining energy only glucose and its polymers (starch and cellulose), as well as lignin, are of interest. The effectiveness of photosynthesis does not exceed 8%, whereas, for the production of plant biomass, a lot of effort must be spent: cultivation, fertilization, and collection of the final product. Thus, the total efficiency of the full cycle of energy production from biomass is estimated to be less than 1%. However, despite all the disadvantages, commercial interest in using biomass is quite large for both economic and environmental reasons. It is possible to turn biomass into energy in the following ways: (1) (2)

Drying followed by incineration (This produces a large amount of ash and smoke, which limits the application of this method); Conversion to liquid or gaseous fuels followed by incineration (At the same time, the energy reserves of the raw materials are lost and the energy conversion process consumes energy). Biomass conversion can be carried out by the following methods:

(1) (2) (3) (4) (5)

Thermolysis (450–800 °C) and hydrothermolysis (250–600 °C)—coal, oils, and gases, CO2 are formed; Pyrolysis (1500 °C)—gases C2 H2 and coal are formed; Gasification (up to 1200 °C)—CO, CH4 , H2, and CO2 are formed; Fermentation—ethanol and CO2 are formed; Anaerobic digestion—CH4 and H2 O are formed.

6.2 Biomass as a Source of Raw Materials for Chemical Synthesis

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Thermolysis and pyrolysis—are the biomass heating in the absence of oxygen. At low temperatures of thermolysis, the main product is charcoal. At high pyrolysis temperatures, the coal content decreases, but the amount of gaseous products (CO, acetylene, and H2 ) increases. Thermolysis and pyrolysis are relatively energy inefficient—more than 50% of the initial energy reserve of biomass is lost. Gasification—is the thermolysis in the presence of air or steam, gaseous products are formed with a high content of oxygen, as well as hydrogen. Used to produce synthesis gas (CO/H2 ), in addition, the resulting gases can be used to produce electricity. Hydrothermolysis—is the process of thermal treatment of biomass with water at high temperatures and pressures of about 30 atm. It was developed by Shell to produce oily materials with low oxygen content, so-called bio-crude. The process is not cost efficient, but it can become so when oil prices rise. Anaerobic digestion (methanogenesis)—is the treatment of biomass with bacteria in the absence of air to form a gas rich in methane—biogas. A ton of dry biomass yields about 300 m3 of biogas containing >50% methane. At present, the production of biogas for use as fuel is economically unprofitable. The existence of plants is associated with the need to recycle waste, for example, sewage from livestock farms. Fermentation—is the process of processing biomass with enzymes or bacterial cultures that it contains with the formation of low-molecular organic compounds (Scheme 6.1). About 93% of ethanol is produced by biotechnological methods. About 60% of ethanol is used as an additive to fuel, 25%—in the chemical industry and 15%— in the food industry. In Brazil, about 16 million liters of ethanol are produced per year. A portion of ethanol (with high water content) is used as fuel in special engines. Ethanol with low water content is mixed with gasoline in an amount of up to 22% and is used in conventional engines [3]. Bioethanol, along with biobutanol and biodiesel at the present stage of the development of human civilization, is considered to be a promising alternative fuel, and dimethyl ether, methane, and hydrogen are considered less promising. However, bioethanol has a number of disadvantages. The disadvantages of bioethanol are as follows: (1)

(2)

Fermentation produces large amounts of by-products containing organic acids (amino acids) and other substances. Not all carbohydrates undergo fermentation by yeast, for example, xylose is not fermented. The solution is the use of other bacteria, for example, E. coli strains that process xylose have been found. Solutions of alcohol with a concentration of 7%–15% are formed, then an energy-intensive distillation process is required; hydrolysis CELLULOSE

Scheme 6.1 Fermentation process

yeast GLUCOSE

ETHANOL

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(3)

According to calculations, the production of a ton of ethanol consumes 72% more energy than is contained in the ethanol itself.

Biobutanol can be obtained by fermentation of sugars with the bacterium Clostridium acetobutylicum. Butanol is 25% more energy-intensive than ethanol, and gives off 10% more energy in the working cycle than gasoline. Butanol is safe, evaporates 6 times slower than ethanol, and 13.5 times less volatile than gasoline. Butanol does not cause corrosion and can be transported by conventional oil pipelines. It not only mixes with gasoline but also can completely replace it without a significant change in engine design. Biodiesel is a diesel fuel, consisting entirely or partially of natural organic components extracted from renewable (mainly vegetable) raw materials, main components are esters of fatty acids with light alcohols (methanol) [4]. The components of biodiesel are formed by the reaction of the transesterification of fats (Scheme 6.2). The main source of biodiesel production is vegetable oils. The content of fatty acids in vegetable oils is shown in Table 6.1. Benefits of using biodiesel include: (1) cleaner combustion; (2) less smoke from combustion; (3) less SOx ; (4) lower content of hydrocarbons in combustion products; and (5) lower CO content. Disadvantages of biodiesel fuel: (1) (2) (3)

In a number of modern fuel systems and engines, biodiesel, whether composite or pure, cannot be used (low shelf life and oxidizability). Exposure to bacteria. Increased aggressiveness to polymer, rubber parts of the fuel system.

In European countries, the term FAME (fatty acid methyl ether)—methyl esters of fatty acids of vegetable oils is most often used to denote diesel biofuel. FAME is

cat

Scheme 6.2 The reaction of transesterification of fats Table 6.1 The content of fatty acids in vegetable oils Fatty acid

Formula

Soybean

Palmitic

C16 H32 O2

11

Stearic

C18 H36 O2

4

Oleic

C18 H34 O2

Linoleic

C18 H32 O2

Linolenic Erucic

Sunflower

Palm

Rapeseed

7

43

3

5

5

1

23

18

41

11

54

69

10

12

C18 H30 O2

8

0

0,2

0,9

C22 H42 O2

0

0

0

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6.2 Biomass as a Source of Raw Materials for Chemical Synthesis

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Table 6.2 Environmental benefits of biodiesel NOx (g/kWh)

Carbon dioxide (g/kWh)

Hydrocarbons (g/kWh)

Particulate matter (g/kWh)

Diesel fuel from oil

8,70

1,00

0,80

0,23

Biodiesel fuel

3,90

–

–

0,10

Euro-3 requirements

5,00

2,00

0,60

0,10

Euro-4 requirements

3,50

1,50

0,46

0,02

used as a composite fuel, with a FAME content of 31 ÷ 36%, the rest is petroleum diesel fuel [5]. Currently, the most commonly used blended diesel biofuel with 5% FAME content. The environmental benefits of biodiesel are presented in Table 6.2. In 1994, the Research Institute for Physical and Chemical Problems of the Belarusian State University created a group to study the technology of biofuel production. In 2003, a technology was developed for the continuous production of methyl esters of rapeseed oil fatty acids. The processing scheme for rape includes the use of straw in the production of solid fuel for power plants, and rapeseed seeds for the production of oil. From the oilcake remaining after the oil is extracted, solid fuel is produced for power plants and components to animal feed. The oil is processed into liquid fuel for internal combustion engines. According to the technology developed by the Institute, a plant for the production of biodiesel with a capacity of 5000 tons per year was created at Grodno-Nitrogen enterprise (Fig. 6.1). Biohydrogen also can be considered as a fuel product of plant origin [6].

Fig. 6.1 Grodno-Nitrogen enterprise created a plant for the production of biodiesel

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Main sources of allocation include the following: (1) (2) (3) (4)

Bio-photolysis of water by green and blue-green algae (cyanobacteria); Photodegradation of organic compounds by photosynthetic bacteria; Fermentation of organic substances in the absence of light, for example, with bacteria Clostridium; Hybrid systems using photosynthetic organisms, and hydrogen-producing bacteria.

The urgent need to find new, more environmentally friendly types of motor fuels was dictated not only by the forecasts of the exhaustibility of oil reserves, but also by the economic crisis, and by the fact that the total consumption of motor fuels is now about 1.8 billion tons per year, in including automobile gasoline—more than 800 million tons per year. When burning such an amount of motor fuels—millions of tons of carbon oxides, methanol, polycyclic carcinogenic hydrocarbons, various types of carbon are thrown into the atmosphere of cities. So, we have considered the processes of obtaining biofuel from biomass. Biomass can also be used to produce chemicals. This direction is referred to as “Chemistry without oil.” Today, the chemical industry consumes up to 10–15% of all oil produced in the world [7]. Therefore, in many countries, the transition of the chemical industry to vegetable raw materials is predicted. For example, in the USA by 2025 it is planned to transfer up to 25% of the entire chemical industry to vegetable raw materials. The transition to vegetable raw materials is possible in the following areas: (1) (2) (3)

Extraction of organic components from biomass by means of supercritical fluids (this is how oils, fats, waxes, terpenes are obtained); The use of natural polymers (starch, cellulose, lignin, and chitin), isolated from biomass; Obtaining of various organic substances, so-called “bioplatform molecules” from biomass by fermentation.

6.3 Basic Chemical Products of Biomass Conversion The main chemical products obtained from renewable raw materials include lubricants, fibers and composites, solvents, polymers, surfactants, adsorbents, dyes, agrochemical products, and pharmaceutical components. As a raw material for the production of these substances and products, carbohydrates accumulated in plants are used. Under the influence of chlorophyll and light from carbon dioxide and water in green parts of plants, sucrose C12 H22 O11 is synthesized, then, as a result of complex biochemical transformations, a whole variety of organic compounds that can be found in annual and perennial plants is formed. Sugar cane and sugar beet accumulate sucrose in significant quantities. They are used to obtain sucrose in a free state. In a number of other plants (cereals, potatoes, etc.) sucrose is converted into a reserve polysaccharide—starch, which is the main source of human nutrition and many animals.

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A considerable part of the sucrose synthesized by plants (more than 60% by weight) is spent by them on the construction of cell walls of tissues that form wood, bark, leaves, and roots of annual and perennial plants. In this case, sucrose is converted into linear high-molecular polysaccharides—mainly in cellulose and in hemicelluloses, as well as in lignin [8]. The greatest number is concentrated in the composition of perennial forest plants. Huge reserves of polysaccharides, some of which are renewed annually, are a potential source of ethanol and many other substances. However, before using them in this direction, the polysaccharides of plant cell walls must first be converted to the corresponding monosaccharides by hydrolysis. An example of such a reaction is the conversion of cellulose to glucose: (C6 H10 O5 )n + (n − 1)H2 O → nC6 H12 O6 . An aqueous solution of hydrolysis products (hydrolyzate) after purification is used in hydrolysis plants as a nutrient medium for the life of various microorganisms. Some types of microorganisms produce enzymes, which, in particular, can convert glucose into ethyl alcohol and carbon dioxide. The yield of ethanol depends on the nature of the feedstock. This can be illustrated by the following examples: from one ton of potatoes, 80–100 L of 100% ethyl alcohol are obtained, from one ton of grain (rye, wheat, rice, maize)—from 270 to 450 L, from one ton of dry sawdust from 150 to 200 L. Low-molecular products derived from carbohydrates include the following: (1) (2) (3) (4) (5)

Lactic acid production from glucose (Scheme 6.3): Obtaining diols from glucose (Scheme 6.4): Obtaining methyl tetrahydrofuran from glucose (Scheme 6.5): Obtaining ascorbic acid from glucose (Scheme 6.6): Obtaining various products from pentosans contained in corn cobs (Scheme 6.7):

From corn starch, the following main products can be obtained: glucose, sorbitol, vitamin C, lactic and polylactic acid, 1,3-propanediol, fructose.

Scheme 6.3 Lactic acid production from glucose

Scheme 6.4 Diols production from glucose

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Scheme 6.5 Methyltetrahydrofuran production from glucose

Scheme 6.6 Ascorbic acid production from glucose

Scheme 6.7 Various products production from pentosans contained in corn cobs

Transformation of acidic groups of fatty acids produces higher alcohols, amides, and salts of fatty acids, higher alkenes, esters of higher alcohols, quaternary ammonium bases, higher amines [9]. The transformation of multiple bonds of unsaturated fatty acids produces acids and alkenes of medium length (metathesis), dicarboxylic acids (upon exposure to H2 O2 and O3 ), cis-trans isomers (under the action of acids or nitrogen oxides), epoxides (in the presence of peracids), diols for the production of polyurethanes (treatment with acids and hydrogen), conjugated fatty acids (under the action of bases). A special group of substances obtained not from oil are bioplastics. Currently, bioplastics based on starch, for example, Plastarch Material are known, from corn raw materials; based on polymers of lactic acid (polylactides) and poly-3hydroxybutyrates. Polyamide 11 (PA 11, Rilsan) is obtained from vegetable oil

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extracted from castor (oil and ornamental plant). Polyethylene from bioethylene— ethylene is known to be produced from renewable raw materials.

6.4 Conclusion It should be noted that much attention is paid to the teaching of “green chemistry” in the world: in Europe and the United States, even schoolchildren get an idea about this subject. Regularly held conferences, seminars on “green” chemistry and sustainable development. It is necessary that both our countries : Belarus and China do not stand aside and join the ranks of supporters of the “green” chemical industry. At the same time, it is necessary to support any initiatives aimed at achieving the ideas of “green” chemistry. There are no doubts that “green” economy is a knowledge-based bioeconomy. It has to transform the knowledge of life sciences and green chemistry into new, sustainable, eco-efficient and competitive products. The following three topics have been identified as being of major importance to facilitate the development of a biobased economy: (1)

(2) (3)

Biocatalysis. It focuses on two aspects: the discovery and improvement of novel selective biocatalysts and the development of a systematic process design technology for a quick and reliable selection of new and clean high-performance manufacturing process configurations. Next generation of high-efficiency fermentation processes, including novel and improved production of microorganisms/hosts. Biorefinery concept. It relies on the best use and valorization of feedstock, optimization, and integration of processes for better efficiency, optimization of inputs (water, energy, etc.), and waste recycling/treatment.

Summarizing what has been said, it is necessary to emphasize that the roadmap for sustainability is through chemistry. The pervasive role of chemistry for our society dictates the next step to a sustainable world namely through chemistry innovations.

References 1. Janet S, Antoine B (2019) 17-Polymers from plants: biomass fixed carbon dioxide as a resource. In: Managing global warming. Academic Press, Pittsburgh, pp 503–525 2. Houghton RA (2008) Biomass. In: Encyclopedia of ecology. Academic Press, Pittsburgh, pp 448–453 3. Ferrie JP, Method for determining the water content of a mixed alcohol/gasoline fuel in an internal combustion engine, and device for implementing same, United States Patent Application 20130317724 4. Kathleen A, Devinder M, Ryan K, da Macelo S (2017) Global biofuels at the crossroads: an overview of technical, policy, and investment complexities in the sustainability of biofuel development. Agriculture 7(4):32–53

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5. Kumar G, Bakonyi P, Periyasamy S, Kim SH, Nemestóthy N, Bélafi-Bakó K (2015) Lignocellulose biohydrogen: practical challenges and recent progress. Renew Sustain Energy Rev 44:728–737 6. Davis R, Tao L, Scarlata C, Tan C, Ross J, Lukas J, Sexton D (2015) Process design and economics for the conversion of lignocellulosic biomass to hydrocarbons, NREL/TP-510062498. Golden, CO, USA, National Renewable Energy Laboratory 7. Solomon B, Bailis R (2014) Sustainable development of biofuels in Latin America and the Caribbean. Springer, New York, NY, USA 8. Hadar Y (2013) Sources for lignocellulosic raw materials for the production of ethanol. In: Lignocellulose conversion. Springer: Heidelberg, Germany 9. De Gorter H, Drabik D, Just D (2015) The economics of biofuel policies. New York, NY, USA, Palgrave 10. Savitskaya TA (2018) Biodegradable composites based on the natural polysaccharides. BSU, Minsk

Chapter 7

Green Chemistry in China and Belarus

Abstract While apart from the traditional chemistry subjects such as organic chemistry, inorganic chemistry, physical chemistry, analytical chemistry, polymer chemistry, and environmental chemistry, the theories of green chemistry also consists of the latest achievements of sociology, anthropology, macroeconomics, and management. That’s why green chemistry is the scientific guidance to set up a new industrial system and reconstruct society in China and Belarus. Keywords National strategy · Green economy · China · Belarus

“In a few decades it won’t be special anymore…Everyone will be doing green chemistry.” Professor Robert H. Crabtree Yale University Chemistry Department

7.1 National Strategy of Green Economy Development in Belarus At present, there is a steadily increased interest in green chemistry and green engineering in academia and business world. Green chemistry and green engineering are still relatively new areas and a bridge to sustainable development. They are tools to drive sustainability through innovations. Whereas green chemistry and green engineering may be seen as being related primarily to the environmental aspects of sustainability, they also have strong ties to eco-efficiency by virtue of the fact that they include resource conservation and efficiency [1]. Meantime, green chemistry and green engineering are related to the social aspects of sustainability because they promote the design of manufacturing processes that are inherently safer, thereby ensuring that workers and residential neighborhoods closed to manufacturing sites are protected. In 2004, Belarus developed a National Strategy for Sustainable Socio-economic Development in the Republic of Belarus up to 2020, in accordance with the principles of “Agenda 21” and other UN documents, taking into account the country-specific natural resources, production, and economic and social potential. At the strategy’s core is the Belarusian model of sustainable development, with prime elements being © Zhejiang University Press 2021 T. Savitskaya et al., Green Chemistry, https://doi.org/10.1007/978-981-16-3746-9_7

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Fig. 7.1 Green economy mark of Belarus

the spiritual, social, economic, and environmental components seen as equal and harmoniously inter-related spheres of human activity [9]. The model is a way of organizing and functioning society, the state, and the national economy through the development of a national identity based on the principles of sustainable balanced development of all the elements, ensuring prevention and mitigation of external and internal threats in the interests of present-day and future generations. The Belarusian model of sustainable development is based on a rational combination of spiritual and material values, on the development of various forms of ownership, on adequate institutional and market infrastructure with effective mechanisms of state and market regulation and an effective social protection system (Fig. 7.1). The commitment of the Republic of Belarus to the principles of a “green” economy is enshrined in the national program documents: (1)

(2)

(3)

National Strategy for Sustainable Social and Economic Development for the period up to 2030 (approved by the Presidium of the Council of Ministers of the Republic of Belarus, Protocol No. 3 of February 10, 2015). The National Action Plan for the Development of the “Green” Economy in the Republic of Belarus until 2020 (Decree of the Council of Ministers of the Republic of Belarus of December 21, 2016, No. 1061) The Republic of Belarus is a participant in the project “Ecologization of the Economy in the Eastern Partnership Countries of the European Union” (national coordinators—the Ministry of Economy and the Ministry of Natural Resources), implemented jointly by UNECE, OECD, UNEP, and UNIDO.

The main directions of the development of “green” economy in the Republic of Belarus are as follows:

7.1 National Strategy of Green Economy Development in Belarus

(1)

(2) (3) (4) (5) (6) (7)

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Reducing the energy intensity of the gross domestic product, increasing energy efficiency, including through the introduction of energy-efficient technologies and materials; Sustainable consumption and production, including government sustainable (“green”) purchases; Increasing the potential of renewable energy sources; Development of electric transport (infrastructure) and urban mobility, implementation of the “smart” cities conception; Construction of energy-efficient residential buildings and increasing the energy efficiency of housing stock; Creation of conditions for the production of organic products; Development of ecological tourism and in particular—ecological tourism in specially protected areas.

On September 20, 2016, the Republic of Belarus became the 30th party to the Paris Agreement [2]. In comparison with many other countries, the advantage of the Republic of Belarus is the higher adaptive potential of the country as a whole, which is provided by: (1) (2) (3)

High forest cover of the territory; Availability of the significant water resources; A significant share of bogs and specially protected natural areas

The obligation of the Republic of Belarus under the Paris Agreement is to reduce greenhouse gas emissions at 28% by 2030 compared to 1990 The policy being pursued in the Republic of Belarus : (1) (2) (3) (4)

Use of renewable energy sources (RES, Fig. 7.2); Introduction of low-carbon and non-carbon technologies that exclude the use of high-carbon fuels such as fuel oil, peat, coal; Introduction of biogas installations at all large complexes for the cattle breeding, pig farms, poultry farms; Implementation of integrated systems for using the energy of biogas, sun, wind for agro-towns;

Fig. 7.2 Structure of renewable energy sources in the Republic of Belarus

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(5)

The introduction of a “carbon tax” and organization of a national carbon market; Increasing the use of electric transport and the decommissioning the gasoline and diesel vehicles of low ecological classes.

Construction of RES installations at facilities owned by individuals and private companies, in order to obtain energy for own use. The electricity produced on the mentioned objects will not enter into the grid at preferential tariffs. These installations do not require compliance with quotas or other permissive or restrictive procedures. They are supposedly projected to be created by 2020 with a total installed capacity of about 10 MW. An economy may be analyzed in terms of its component parts, often called “sectors”. Sectors may be widely drawn to include groups of industries (e.g., the engineering industries) or narrowly drawn to identify parts of industries (e.g., wood processing industry) [3]. The chemical and petrochemical sector is one of the most important in the Belarusian economy, accounting for over 12% of GDP. It is an invaluable source of foreign exchange with almost 20% of all exports coming from the sector. One of the remarkable steps to the realization of the concept of green economy is the implementation of ISO standards of ISO 14000 series by Belarusian enterprises. This helps to decrease air and water pollution and waste, and creates new jobs.

7.2 Green Chemistry as an Educational Platform for Green Economy In 2016 Roger Sheldon wrote: “Over the last 25 years the concept of green chemistry, in particular the principle of designing synthetic methods to maximize the incorporation of all raw materials in the product, and the underpinning metrics, atom economy and the E factor, have been widely embraced by industry and academia worldwide. The shift toward green chemistry and resource efficiency is accelerating and has been supplemented by the drive toward substitution of the unsustainable use of fossil resources by sustainable use of renewable biomass with the help of green chemoand biocatalytic processes. Looking to the future, an important spin-off of this trend will be the development of alternative, more sustainable products and, ultimately, the design of products with their regeneration and circularity of production in mind, in a truly green economy” [4]. Green chemistry is a multifaceted discipline that has been created as a contribution of chemistry to sustainable development, avoiding damage to the environment. Obviously, the concern is greater in the industry, since social alarm and legislative limitations have a more direct impact in this case. More than ever, Green chemistry can be considered a powerful tool to modify unsustainable principles in Green chemistry, Engineering, and correlated are all over the world [5, 6]. It is well known that the contextualized insertion of the green chemistry principles into

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curricula in higher education institutions can contribute to better professional education, engaging students to learn conceptual contents associated to procedural and attitudinal subjects.

7.2.1 Benefits of Green Chemistry Human health: (1) (2) (3)

(4)

(5)

(6)

Cleaner air: less release of hazardous chemicals to air leading to less damage to lungs; Cleaner water: less release of hazardous chemical wastes to water leading to cleaner drinking and recreational water; Increased safety for workers in the chemical industry; less use of toxic materials; less personal protective equipment required; less potential for accidents (e.g., fires or explosions); Safer consumer products of all types: new, safer products will become available for purchase; some products (e.g., drugs) will be made with less waste; some products (i.e., pesticides, cleaning products) will be replacements for less safe products; Safer food: elimination of persistent toxic chemicals that can enter the food chain; safer pesticides that are toxic only to specific pests and degrade rapidly after use; Less exposure to such toxic chemicals as endocrine disruptors.

Environment: (1)

(2) (3) (4) (5)

Many chemicals end up in the environment by intentional release during use (e.g., pesticides), by unintended releases (including emissions during manufacturing), or by disposal. Green chemicals either degrade to innocuous products or are recovered for further use; Plants and animals suffer less harm from toxic chemicals in the environment; Lower potential for global warming, ozone depletion, and smog formation; Less chemical disruption of ecosystems; Less use of landfills, especially hazardous waste landfills.

Economy and business: (1) (2) (3) (4)

Higher yields for chemical reactions, consuming smaller amounts of feedstock to obtain the same amount of product; Fewer synthetic steps, often allowing faster manufacturing of products, increasing plant capacity, and saving energy and water; Reduced waste, eliminating costly remediation, hazardous waste disposal, and end-of-the-pipe treatments; Allow replacement of a purchased feedstock by a waste product;

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(5) (6)

Better performance so that less product is needed to achieve the same function; Reduced use of petroleum products, slowing their depletion and avoiding their hazards and price fluctuations; Reduced manufacturing plant size or footprint through increased throughput; Increased consumer sales by earning and displaying a safer-product label (e.g., Safer Choice labeling); Improved competitiveness of chemical manufacturers and their customers.

(7) (8) (9)

7.2.2 Some Examples of Green Chemistry in Belarus One of the principles of green chemistry is the usage of biomass instead of crude oil for the production of chemicals and chemical goods. Wood refers to the term biomass and it is mainly composed of cellulose, lignin, and hemicelluloses. Cellulose is the main component of wood and lignin is the main by-product of cellulose extraction. Green approach to both of these polymers resulted in creating a new process for hydrocellulose fiber production and a new sorbent for oil spill removal based on hydrolysis lignin was developed at the Belarusian State University (BSU). For closing the life cycle of wood, Belarusian researchers have developed the effective organo-mineral fertilizer based on a combination of lignin and worked-out fiber production coagulation bath constituted the inorganic salts mixture [8]. It is worth pointing out that this approach provides the use of two main wood components in the frame of “cradle to cradle” cycle. This is the start of going on the road to circular economy design considerations for research and process. The circular economy has arisen as an ambitious and necessary alternative to the current “take, make, dispose” linear economy. It is a philosophy of chemical research and engineering to guide the invention of materials for the circular economy (Fig. 7.3). As follows from Fig. 7.3, three green processes have been developed on the basis of wood components. (1)

(2)

(3)

The first line is the Greencel process for hydrocellulose fiber production. The desirable product is the hydrocellulose fibers. The main feature of the process is the use of the aqueous solutions of orthophosphoric acid (nonvolatile and low-toxic solvent). Very small water consumption is one more green feature of the process. It is an example of cleaner production. Fibers are for a person’s clothes. The by-product is a precipitating bath that is a mixture of phosphorous salts of potassium. It can be used as a mineral fertilizer in the liquid or solid state. The fertilizer we use for the growing up plants (food for person). The second line is the production of the sorbent Lignosorb by the hydrophobization of hydrolysis lignin. After hydrophobization lignin becomes a good sorbent for oil spill removal and for waste recovery. Lignin saturated by oil is a composite fuel. The third line is the effective organo-mineral fertilizer production as a combination of lignin and worked-out coagulation salted bath of fiber production.

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Fig. 7.3 The life cycle of wood

BSU researchers implemented the following Green Chemistry principles: fewer stages, less auxiliary substances, the use of less toxic substances, low energy and water consumption, the use of the ambient temperature and pressure, the use of nonvolatile and low-toxic solvent, the reduction of atmospheric emissions and the wastewater discharges. Green process for biodiesel production based on rapeseed oil was implemented by the researchers from BSU as well. Researchers from Belarusian State Technological University will develop special galvanic cells of new designs for the green energy industry within the Union State project on green energy and green chemistry.

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7.3 Achievements in Green Chemistry Research and Technologies in China With the in-depth development of the chemical industry, its products have been tremendously abundant. The relevant data shows that there are more than 70,000 types of chemical products in the world so far with a 5,000 billion yuan of the total output value of the chemical industry. The abundance of chemical products not only greatly satisfies people’s material needs, but also realizes illness control and life extension, in the meanwhile, their usages inevitably produce a great amount of wastes, which threatens both environment and the health of people. No less than 0.3–0.4 billion tons of hazardous wastes are produced globally per year (the wastewater, waste gas, and solid wastes released from the chemical industry in China accounts for 22.5%, 7.82%, 5.93% of the total global industrial emissions, respectively) also bring great environmental disaster. So, most people will turn pale at the mention of chemistry, and the infinite amplification of the negative effects of chemistry and negligence of its positive effects are truly the reflections of the incomprehension and misunderstanding of chemistry. But as long as you observe and consider studiously, you’ll know how great benefits the advancements of chemical technology have brought to our human beings in aspects of our basic necessities of life and fighting diseases. The development of medicinal chemistry contributes to treat many diseases and extend human life; the innovation of polymer technology generates new materials for clothing and construction; the progress of fertilizers has kept pests under control and increased production. Nothing can be achieved without chemists. It is no exaggeration to say that people can’t live without chemistry. It has been a scientific challenge to solve this contradiction in the twenty-first century. Consequently, green chemistry is developed and prospered in our lives.

7.3.1 Background and Premise of Green Chemistry in China The ecological development and human existence have been restrained seriously due to the constant collision of the continuing development of the economy and increasing population, as well as the limited natural resources and serious environmental pollution. In addition, the huge amount of pollution residues from the traditional chemical industry and the contempt upon the environment during the accelerating industrialization of all nations, all make the call to green chemistry louder and louder. It’s distressing to see the current environmental situation—severe air pollution of frequent fog and haze, geological disasters caused by acid rain, global warming and the depleted ozone layer, scarce freshwater resources and serious marine pollution, vegetation harvesting and soil erosion, challenged biodiversity and ecological balance. It literally threatens the living environment for humans of all time. On account of this, green chemistry is required to spurn the extensive processing of traditional chemical industry, and to focus on efficient use of natural resources so as to

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coordinate the economic development and environmental protection. Only through measures addressing both symptoms and roots, pollution and energy consumption can be reduced from the source, so that zero emission and pollution can be realized, and performance of atom economy can become possible with a more balanced and environment-friendly earth ecosystem. Therefore, it is very important and imperative to guide the development of green chemistry properly. The emerging tide of green chemistry and clean energy processing technology in the world has attracted great attention across scientific circles in China and spurred Chinese green chemistry to be gradually active. As early as 1985, the famous Chinese inorganic chemist, the academician DAI Anbang first proposed that “we should pay attention to the adverse effects of chemical industrial processes on resources and environment” in the 3rd National Inorganic Chemistry Conference. And the DDT shutdown of the Shacheng chemical plant in 1986 was regarded as the kick-off for environmental protection in China. In 1995, the issue of green chemistry was put on the agenda. Firstly, the research project of green chemistry and technology for academician was confirmed by the chemistry department of CAS (Chinese Academy of Sciences) aiming at putting forward suggestions for the development of green chemistry and technology, as well as elimination and reduction of environmental pollution sources based upon a great amount of investigations on the present situation and trends of green chemistry at home and abroad. The Ministry of Science and Technology organized the investigations and research of green chemistry and technology, and included it in the Basic Research of the 9th Five-Year Plan. The symposium on green chemistry and technology in the industry held in 1996 has the issues of pollution and prevention in industrial production discussed. In May 1997, an academic seminar on the subject of “the Challenge to Science from Sustainable Development—Green Chemistry” was held in Beijing. The central topics were: the challenge to material science from sustainable development, the green revolution in the chemical industry, and some substantial scientific problems in green technology, as well as the development strategy of green chemistry in China. In the same year, among the key basic research projects of the 9th Five-Year Plan, “the EnvironmentalFriendly Catalytic Chemistry and Chemical Reaction Engineering in Petrochemical Industry” jointly funded by Natural Science Foundation of China and China Petrochemical Corp was officially launched. The National Basic Research Program of China also took the basic research of green chemistry as one of the important directions to support. In 1998, the first International Symposium on Green Chemistry was held in USTC (University of Science and Technology of China). And in December of the same year, the 16th JIUHUA Science Forum was held in Beijing JIUHUA Spa & Resort, the specialists present conducted a full discussion about the basic scientific problems of green chemistry in a strategic perspective of sustainable development, meanwhile proposed how to prioritize and deploy relevant research work in China during the period of the 10th Five-Year Plan, and determined three critical research areas in green chemistry. The first one was the research on synthesis technology, methodology, and process in green chemistry, the second was those basic scientific problems in the utilization and transformation of renewable resources, and the third was the pivotal scientific problems of green chemistry in the effective use of mineral

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wealth. Besides, universities began to set up green chemistry research institutes one after another, such as the R&D Center of green technology in USTC, the Research Center of green chemistry and technology in SCU (Sichuan University), and so on. Although it started late in China, green chemistry has been highly regarded and amply augmented in recent years.

7.3.2 Current Situation of Green Chemistry in China During the past 20 years, green chemistry has developed rapidly. Important progress have been made continuously in its basic research and technology development, and a lot of research papers are published every year. A number of new industries have been formed and have shown sound developing momentum by means of many relative patents being licensed and green technologies being used. In “the Environmental-Friendly Catalytic Chemistry and Chemical Reaction Engineering in Petrochemical Industry” among the key basic research projects, the basic directional research on the greening of organic chemical technology has been conducted and has reached staged achievements. Such as the optimizing processing and utilization of petroleum resources guaranteed strategic significance to the sustainable development of the economy and society. The greening of petrochemical technology serves not only the need for our ecosystem protection but also the need for fully use resources and cost reduction. In order to obtain clean gasoline, it required catalytic cracking to not merely produce high-octane gasoline but increasingly synthesize alkylation and etherification materials such as component alkene of high-octane gasoline. On the other hand, it is also required to develop the synthetic methods of alkylation, isomerization, and etherification. China has successfully developed catalytic cracking technology to compound high-octane gasoline as well as abundant alkenes. The research of advanced molecular sieve technology for nano, mesoporous, and shape-selective are in progress both at home and abroad to improve the substandard percentages of alkene, benzene, and sulfur during the production, and make genuine “clean gasoline”. The catalytic conversion of supercritical hydrocarbon which is studied in China is a new field of chemical research, and probably will bring up innovation to the production technology of clean gasoline. Green chemistry has also been well applied and developed in detergent and clean coal. In 1993, China started to set up greenwashing industry and studied new phosphate-free detergent powder, and finally succeeded in development in 1995 with the efforts of all parties. Various high-quality phosphate-free detergent came out and were put into production successively. Compared with the ordinary ones, phosphate-free detergent has the advantages of condensed, low-foam, easier to dissolve, and bleach. Above all, it is non-phosphorus, nontoxic, non-harm, and nonwater-pollution. Chinese finally have our own green washing products. As for coal, it’s an inarguable fact that it will result in environmental pollution after burning as a sort of energy. Through CCT (clean coal technology), coal can be transformed into town gas, methanol, heavy oil, light oil, phenol, and sulfur, which not only prevent

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pollution but also increase economic benefits for sustainable development. China mainly developed the following CCT about underground coal gasification, industrial briquette, coal water slurry gasification, coal liquefaction, combined cycle power generation by clean coal, and comprehensive utilization of coal waste, etc. The CCT of circulating fluidized beds invented by Tsinghai university is able to effectively solve the environmental pollution led by coal burning. China has gained some great achievements in the study of high atom economy, especially in the organic synthesis of transition-metal catalysis, for example, the AU (atom utilization) in alkynes isomerization of transition-metal catalysis and intramolecular cyclization of alkenes has reached 100%. This outcome played a leading role in the world and has been widely used in the synthesis of target molecules by scientists of all countries. And we have done a lot of work in other hot areas of green chemistry, from the synthesis of chiral ligands to the asymmetric synthesis catalyzed by asymmetric catalysis. Moreover, China has taken a great deal of research in SCF (supercritical fluid), including the physicochemical behavior, catalytic and polymerization reaction of compounds in supercritical CO2. They are of a certain influence. Research teams with accumulated experiences and superior academic levels in heterogeneous catalysis research emerged at the right moment, since catalyst serves a vital role which manifests not only in the crucial scientific bases that catalysis occupied in green chemistry implementation, but in more than 90% chemical industrial processes need catalytic technology. The appearance of green chemistry provided a great opportunity for the rapid development of the chemical industry in China. Gradual perfection of green chemical technology and products will fulfill the clean production and the integration of resource utilization through making waste profitable and will make the recycling economy within the emerging chemical industrial parks possible.

7.3.3 Strategies and Outlook of Green Chemistry in China Except for fundamentally improving the living environment of humans, green chemistry can also substantially promote economic benefits. The industrial revolution triggered by it just rises around the world, and will run through the next century. It is undoubtedly a rare opportunity for a developing country like China, so, we should jump at the chance of green revolution and strive to develop green chemistry to meet the challenges posed by the increasingly severe ecological crisis. (1)

Substantial support for the green chemistry concept from government Green chemistry has become an act of government in western countries. Chinese governments at all levels should fully assess the impact of this industrial revolution on future human society, timely adjust industrial structure, correctly view and treat the efficiency of input and output with a long-term vision, as well as gradually abandon their support for some badly polluting traditional chemical industry, instead to back up the greening transformation of

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the traditional chemical industry, and take the side of exploration and research in green technology, meanwhile, encourage the development of cleaning technology, reduce pollution sources, and make environmental-friendly products. Development of green chemistry technology in crucial areas combined with national conditions Based upon sustainable development, green chemistry has achieved cleaner and more ingenious results through researching new theories and methods. In light of economic construction and sustainable development strategy, Chinese S&T(science and technology) workers should adjust their research fields and direction timely for the sake of national needs and human progress. The author suggests that the following areas should be studied in terms of our national conditions at present: Green biochemical technology: Modern biotechnology and chemical technology should be applied comprehensively to develop biochemical engineering such as biochar desulfurization, microbial paper making, new biomass energy, etc. Experts predicted that we could obtain 2.0 × 108 kg of ethanol, 8.0 × 1010 kg of furaldehyde, and 3.0 × 108 kg of lignin from 1.5 × 109 kg of crop straws per year in China, as well as tens of billions of dollars, provided the biotechnology and green technology being used. Thus, our strategic target of green chemistry development is to transform biological substances into chemical materials and energy. CCT (clean goal technology): China is one of the largest coal producers and consumers in the world, as well as one of the several countries with coal as their main energy resources. Soot and chemical pollution generated by traditional usage of coal has become the main types of environmental pollution in China. The CCT, an important area of international high-tech competition, is designated to make the most use of energy and minimize the emission of pollutants at the same time. It is a technology integration in multilevel and multidiscipline, including various progressive conventional technologies, innovative and high technologies, leading-edge techniques. The average utilization of coal is only about 30% in China, 10% lower than the world’s average, and 25%–28% lower than that of the developed countries. Hence, striving to develop CCT is the only way to improve the environmental pollution status in China and the inevitable course to realize the strategy of green industry. Ecological fertilizers: China is a big agricultural country with the first place of fertilizer consumption and low utilization rate in the world. Huge resource waste and environmental pollution rised on account of 50% of fertilizers entering environment. For the purpose of adapting the development of ecological agriculture, chemical enterprises should be trying to research and develop ecological fertilizers in order to achieve the enhancement of fertilizer’s effectiveness, soil improvement, less agricultural pollution, and the sustainable development of agriculture. Higher effective and lower toxic pesticides: Most Chinese pesticides produced in the past and at present are of highly toxic chemical varieties, which pollute both soil and air during production and use, besides, break the

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ecological balance and lead to deterioration of the ecological environment. Green chemistry is duty-bound to study the synthesis of lower toxicity, even no harm, better selectivity, higher bioactivity, and cheaper cost fertilizers to promote the industrialization of green agriculture. Cleaning and economic manufacture of fine chemicals: Most fine chemicals are employed as supporting or raw materials in production and life, some participate in the production process, others are in the application process. They serve significant purposes in the national economy. In consequence, it is of great social and economical benefits to explore the green synthesis of fine chemicals with both stronger selectivity and efficient atom economy [7]. Reconstruction of Industrial System and Society under the Scientific Guidance of Green Chemistry Green chemistry is strongly backed up by various theories, which contain not only the eclectic philosophy reflections but also the scientific guidance to tangible production. The communique of the 5th Plenary Session on the 18th CPC Central Committee definitely proposed the concepts of innovation, coordination, green development, and sharing ideas. And President XI also put forward that “China’s development will focus more on efficiency and quality, more on innovation-driven, more on justice and equity, more on green development and opening up” on the 10th G20 summit and the 23rd APEC Economic leaders’ meeting. The “five development concepts” are the epistemological guidance to the future direction in the 13th Five-Year Plan, while the “five focus-more-on” are the methodological framework for the future development. It is observed that the concept of green development is a principle line for China’s future from the perspective of epistemology or methodology. To truly achieve green development, we must establish a sustainable industrial system with a pleasant ecological environment and resource conservation, and create a harmonious social atmosphere regarding a green lifestyle. From the beginning of the 1st Five-Year Plan for the national economy in 1956, China has divided its industrial system into two (light and heavy, except the Defense Industry). This division has had a momentous impact on China’s industrial development, but such an oriented system undoubtedly laid too much emphasis on production efficiency. For this reason, many people counterpose green development to production after having awareness of the significance of green development. They speculate that the economic benefits would be sacrificed whenever green development is mentioned. Nevertheless, what green development stresses, especially green chemistry, is not inconsistent with economic interests, but the damage to the ecological environment cannot be ignored simply because of the pursuit of financial interests. The core idea of green development is the coexistence of green and development. Lucid waters and lush mountains are invaluable assets. While apart from the traditional chemistry subjects, such as organic chemistry, inorganic chemistry, physical chemistry, analytical chemistry, polymer chemistry, and environmental chemistry, the theories of green chemistry also consist of the latest achievements of sociology, anthropology,

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macroeconomics, and management. That’s why green chemistry is the scientific guidance to set up a new industrial system and reconstruct society in China.

7.4 Conclusion Twelve principles of green chemistry and green engineering have been proposed to guide scientists and engineers in developing greener processes. These principles are in general accepted by most of the people and have proven very powerful in disseminating the intent and guidelines of green chemistry and green engineering. However, one can summarize and simplify all of them. At the end of the day, applying green chemistry and green principles to your work as an engineer or process chemist means that when designing chemical routes, selecting reactors, designing chemical processes, building plants, and so on, you should strive to: (1) (2) (3)

Maximize resource efficiency; Eliminate and minimize hazards and pollutions; Design systems holistically, using life cycle thinking.

But are these principles enough? Do they cover all the previous advice that we have given? The main thing is our new thinking that will drive us to design better, cheaper, cleaner, inherently safer processes from the early beginning based on the famous motto “Sick prevention, not cure!” For summarizing your success in green chemistry studying, we propose the following case study: Green Star: This is a new semi-quantitative metric, Green Star (GS), for evaluation of the global greenness of chemical reactions used in teaching laboratories. Its purpose is to help choose the more acceptable reactions for implementing Green Chemistry (GC) and to identify suitable modifications of protocols to improve the greenness of the chemistry practiced by students. GS considers globally, in principle, all the Twelve Principles of GC. The metric consists of the evaluation of the greenness of the reaction for each principle by pre-defined criteria, followed by a graphical representation of the results in an Excel radar chart. The fuller the chart, the higher degree of greenness. To analyze the iron (II) oxalate dihydrate synthesis performed under several sets of conditions to pursue the implementation of greenness [“Green Star”: a holistic Green Chemistry metric for evaluation of teaching laboratory experiments. M. Gabriela etc./Green Chemistry Letters and Reviews Vol. 3, No. 2, June 2010, 149–159. https:// doi.org/10.1080/17518251003623376]. This case study illustrates the construction and the scope of the metric.

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