Green Solvents for Chemistry: Perspectives and Practice William M. Nelson OXFORD UNIVERSITY PRESS GREEN SOLVENTS FOR CHEMISTRY This page intentionally left blank Green Solvents for Chemistry Perspectives and Practice William M. Nelson 1 2003 3 Oxford New York Auckland Bangkok Buenos Aires Cape Town Chennai Dar es Salaam Delhi Hong Kong Istanbul Karachi Kolkata Kuala Lumpur Madrid Melbourne Mexico City Mumbai Nairobi Sa˜o Paulo Shanghai Taipei Tokyo Toronto Copyright 2003 by Oxford University Press, Inc. Published by Oxford University Press, Inc. 198 Madison Avenue, New York, New York 10016 www.oup.com Oxford is a registered trademark of Oxford University Press All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior permission of Oxford University Press. Library of Congress Cataloging-in-Publication Data Nelson, William M. Green solvents for chemistry : perspectives and practice / William M. Nelson. p. cm. — (Green chemistry series) Includes bibliographical references and index. ISBN 0-19-515736-2 1. Solvents. 2. Environmental chemistry—Industrial applications. I. Title. II. Series. TP247.5.N42 2003 661′.807—dc21 2002041662 987654321 Printed in the United States of America on acid-free paper For Millie, whose love and support has kept me on track and for Maria, Milee, Liam, and Madeleine, who are my priceless jewels This page intentionally left blank Contents 1. Philosophy of the Environment, 3 1.1 The Emerging Paradigm, 3 1.2 Pollution Prevention and Green Chemistry, 6 1.3 Philosophy in Practice, 11 1.4 Solvents, 13 1.5 Future Direction, 17 1.6 Subject Content of Book, 18 2. Chemical Practice and Solvent Usage, 20 2.1 Solvent Usage, 20 2.2 Pollution: Effects of solvents, 23 2.3 Applications of Solvents, 26 2.4 Broad Areas of Application, 26 2.5 Domain and Range of Solvent Employment, 31 2.6 Global Effects of Solvent Usage, 32 2.7 Challenge Offered to the Chemical Community, 46 2.8 Solvent Supply and Demand, 49 3. Solvation and Solvent Phenomena, 51 3.1 Introduction, 51 3.2 Physical Properties of Solvents, 51 viii Contents 3.3 Chemical Properites of Solvents, 53 3.4 Solvation Chemistry, 60 3.5 Sovent Effects on Chemical Phenomena, 76 3.6 Solvent Roles, 87 3.7 Solvent Effects and Green Chemistry, 89 4. Green Solvents in Green Chemistry, 91 4.1 Definition of Green Solvents, 91 4.2 Specific Health and Environmental Requirements, 94 4.3 Solvents in Terms of Life-Cycle Analysis, 96 4.4 Life-Cycle Assessment, 97 4.5 Life-Cycle Assessment: Its Application to Solvents, 101 4.6 A Proposed LCA Approach to Solvent Selection, 104 4.7 Proposed Checklist for Solvent Use Evaluation, 107 4.8 Practical Approach to Life-Cycle Evaluation of Solvent Usage, 108 4.9 LCA Leading to Total Quality Management (TQM), 109 4.10 Concluding Comments on LCA, 110 4.11 Green Solvents, 111 5. Criteria for Selection and/or Design of Green Solvents, 116 5.1 The Need for Green Solvents, 116 5.2 Criteria to Evaluate Solvents, 119 5.3 Reversibility of Toxicity, 120 5.4 Concept of Receptors, 121 5.5 Mode of Entry of Toxins, 121 5.6 Translocation of Xenobiotics, 123 5.7 Storage of Chemicals in the Body, 124 5.8 Interpretation of Toxicity, 125 5.9 Methodology to Evaluate Green Solvents, 126 5.10 Presently Available Solvents, 129 6. Green Solvents for Academic Chemistry, 133 6.1 Environmental Concerns for Educational Institutions, 133 6.2 Green Chemistry Alternatives, 136 6.3 Early Chemistries: Elementary through High School, 136 6.4 Undergraduate/Graduate Schools, 139 6.5 Organic Chemistry, 142 6.6 Readily Available Drop-in Replacements, 180 6.7 Inorganic Chemistry, 187 6.8 Nuclear and Photochemistry, 188 6.9 Analytical Chemistry, 191 Contents ix 6.10 Biochemistry, 194 6.11 Medicinal Chemistry, 195 6.12 Teaching Laboratories, 196 7. Green Solvents for Industrial Chemistry, 198 7.1 Environmentally Friendly Processes, 198 7.2 Industry’s Response to the Global Environment, 200 7.3 Occupational Toxicology, 202 7.4 What Are Green Industrial Solvents? 207 7.5 Solvents by Industrial Reaction Process, 211 7.6 Alternative Solvents for Separation Processes, 243 7.7 Military Solvents, 245 7.8 Future of Industrial Solvents, 247 8. Green Solvents for Practical and Ordinary Chemical Usage, 252 8.1 Why This Area? 252 8.2 Ordinary Solvent Usage, 255 8.3 Household Solvents, 259 8.4 Recreational and Transportation Solvents, 260 8.5 Evaluating Chemistries, 263 9. Green Solvents: Ecology and Economics, 272 9.1 Place of Green Solvents in Chemistry Practices, 272 9.2 Green Solvents: Epilogue, 273 9.3 Economics and Ecology, 275 9.4 Future Steps, 276 Appendices, 295 References, 345 Author Index, 378 Subject Index, 386 This page intentionally left blank GREEN SOLVENTS FOR CHEMISTRY Knowledge is of two kinds. We know a subject ourselves or we know where we can find information upon it. —Samuel Johnson 1 Philosophy of the Environment 1.1 The Emerging Paradigm Let us put chemical usage in context. There is justifiably a concern over the adverse effects of chemicals on human health and the environment. The source of chemicals may be industrial, commercial, or adventitious. Environmental quality is a concern in the United States and throughout the world. This concern is important today. Our world has heightened environmental awareness, fueled by public interest groups and the media. Public awareness is growing of the processes involved in the use, manufac- turing, and effect of many chemicals on the environment, including the generation of waste, the disruption of ecosystems, and the depletion of natural resources. Current patterns of chemical development threaten to exceed the limits of sustainability in terms of resource utilization and waste management, and also pose potential threats to global climate, vegetation, and agriculture. According to the U.S. Environmental Pro- tection Agency (EPA), about 123 billion tons of industrial wastes are generated annu- ally in the United States, and more than a third of this is hazardous waste. This presents a challenge to the chemical industry. Although the EPA has striven to reduce the impact of toxic chemicals, the efforts have focused primarily on exposure-based approaches. Within the United States, the Pollution Prevention Act of 1990 introduced a new era in regulatory philosophy and policy. The emphasis became the prevention of toxic substances at their source. Green chemistry aims at accomplishing pollution prevention through the design of safer chemicals and the use of more environmentally friendly chemical processes. Green chemistry provides the unifying backbone of this book. Realizing the potential of 3 4 Green Solvents for Chemistry green chemistry will require major changes in the current practices of both academia and industry. Fundamentally, all those associated with the development, manufacture, and use of industrial chemicals must understand green chemistry. New ideas, concepts, and technologies, like green solvents, must replace outdated ones. Designing safer chemicals is essential in today’s chemical environment. “Science is necessary but not sufficient” (Maltoni and Selikoff, 1988), and we must balance the contributions of chemistry with the issues of the broader scientific community, public institutions, industry, and those concerned with ethical and social concerns. Experience reveals that safer chemicals and chemical processes provide competitive advantages by reducing the costs of production and waste management, encouraging innovation in novel chemical syntheses, and developing new markets. The chemical industry faces a major challenge in fully embracing this new paradigm (Wicks and Yeske, 1996). 1.1.1 Background The environment is a complex nexus of interdependent dynamic activities closely related to the internal or external chemistries that support them. Chemists pollute the environment by inducing a change in the supporting chemistry. This occurs when the practice of a human technology jeopardizes any living activities that are recognized to be important (Collins, 1995). The emerging environmental philosophy is a rational reaction to the alarm that pollution has engendered among visionaries such as Rachel Carson who published her alert Silent Spring in 1962 (Carson, 1962). The imperative to attend to global environmental issues includes numerous individuals: government officials and scientists who evaluate and regulate against pollution, commentators who raise public consciousness about pollution, corporate executives who shoulder much of the responsibility for minimizing pollution, and concerned citizens. Chemistry is the tool in the hands of the artisan. However, human activities lead to “randomness.” In other words, our activities tend to leave waste. With the power of science and technology comes a great responsibility not to pollute. While excuses continue to be invented, the proportion of our population who realizes how much we have to change is growing substantially. As a result, our collective energy is being redirected wisely, and this is especially true in the area of chemistry (Anastas, 1996). Chemistry comprises so large a component of modern technology that the develop- ment of green technologies is significantly a chemical enterprise. 1.1.2 Pollution Prevention Pollution prevention (P2) is a bold vision that confronts the global problem of environ- mental pollution. P2 presents an operative paradigm requiring a fundamentally differ- ent approach to the way industry and technologies accomplish their tasks. Waste and pollutants are prevented where they originate. This necessitates changes in manufac- turing technologies and practices, chemicals and other raw materials, and even prod- ucts and packaging. In terms of scientific revolutions, this constitutes a paradigm shift (Kuhn, 1996). The period between 1984 and 1986 marks the beginning of the current P2 move- ment in the United States. Since that time, the pollution prevention idea has grown into a significant international movement.