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Current printing (last digit): 10 9 8 7 6 5 4 3 2 1 PRINTED IN THE UNITED STATES OF AMERICA Preface This book is intended for chemists, chemical engineers, and others who want to see a better world through chemistry and a transition from its present unsustainable course1to a sustainable future.2(A sustainable future is one that allows future gen- erations as many options as we have today.) It is meant to serve as an introduction to the emerging field of green chemistry— of pollution prevention. It is based on a one-semester three-credit course3given at the senior–graduate level interface at the University of Delaware each year from 1995 to 1998. Books and courses in environmental chemistry usually deal with contaminants that enter air, water, and soil as a result of human activities: how to analyze for them and what to add to the smokestack or tailpipe to eliminate them. They are also concerned with how to get the contaminants out of the soil once they are there. Because texts such as those by Andrews et al.,4Baird,5Crosby,6Gupta,7Macalady,8Manahan,9and Spiro and Stigliani10cover this area adequately, such material need not be repeated here. Green chemistry11 avoids pollution by utilizing processes that are “benign by design.” (The industrial ecology12 being studied by engineers and green chemistry are both parts of one approach to a sustainable future.) Ideally, these processes use nontoxic chemicals13and produce no waste, while saving energy and helping our society achieve a transition to a sustain- able economy. It had its origins in programs such as 3M’s “Pollution Prevention Pays.” It was formalized in the United States by the Pollution Prevention Act of 1990. Since then, the U.S. Environmental Protection Agency and the National Science Foundation have been making small grants for research in the area. Some of the results have been summarized in symposia organized by these agencies.14 This book cuts across traditional disciplinary lines in an effort to achieve a holistic view. The material is drawn from in- organic chemistry, biochemistry, organic chemistry, chemical engineering, materials science, polymer chemistry, conserva- tion, etc. While the book is concerned primarily with chemistry, it is necessary to indicate how this fits into the larger soci- etal problems. For example, in the discussion of the chemistry of low-emissivity windows and photovoltaic cells, it is also pointed out that enormous energy savings would result from incorporating passive solar heating and cooling in building de- sign. Living close enough to walk or bike to work or to use public transportation instead of driving alone will save much more energy than would better windows. (Two common criticisms of scientists is that their training is too narrow and that they do not consider the social impacts of their work.) This book begins with a chapter on the need for green chemistry, including the toxicity of chemicals and the need for min- imization of waste. The next three chapters deal with the methods that are being studied to replace some especially noxious materials. Chapters 5–8 cover various ways to improve separations and to reduce waste. Chapter 9 continues this theme and switches to combinations of biology and chemistry. Chapter 10 discusses many optical resolutions done by enzymes or whole cells. Chapter 11, on agrochemicals, continues the biological theme. Chapters 12 through 15 cover various aspects of sustainability, such as where energy and materials will come from if not from petroleum, natural gas, or coal; how to pro- mote sustainability by making things last longer; and the role of recycling in reducing demands on the natural resource base. The last three chapters try to answer the question that arises at nearly every meeting on green chemistry: Why is it taking so long for society to implement new knowledge of how to be green? The topics within these chapters are not confined to specific areas. For example, cyclodextrins are discussed not only un- der supported reagents, but also under separations by inclusion compounds or under chemistry in water. Surfactants have iii iv Preface been placed under doing chemistry in water. They are also mentioned as alternatives for cleaning with organic solvents and in the discussion on materials from renewable sources. An effort has been made to cross-reference such items. But for the reader who has any doubt about where to find an item, a comprehensive index is included. The industrial chemistry on which much green chemistry is based may be foreign to many in academia, but many good references are available.15There is much more emphasis in industrial chemistry on catalysis and the organometallic mech- anisms that often go with them. Improved catalysts are often the key to improved productivity, using less energy and gener- ating less waste.16Again, many good sources of information are available.17In addition, there are two books on the chem- istry and biology of water, air, and soil.18 Each chapter in Introduction to Green Chemistrylists recommended reading, consisting primarily of review papers and portions of books and encyclopedias. This allows detailed study of a subject. The introductions to current journal articles often contain valuable references on the status of a field and trends in research. However, the traditional grain of salt should be applied to some news items from trade journals, which may be little more than camouflaged advertisements. The examples in the book are drawn from throughout the world. In the student exercises that accompany each chapter, readers are often asked to obtain data on their specific location. In the United States, one need look no further than the local newspaper for the results of the toxic substances release inventory. This data can also be found on websites of the U.S. En- vironmental Protection Agency (http://www.epa.gov/opptintr/tri) and state environmental agencies,19as well as on compa- rable websites of other countries (e.g., http://www.unweltbundesamt.de for the German environmental agency). Non- governmental organizations also post some of this data (e.g., the Environmental Defense “Chemical Scorecard,” www.scorecard.org, and the Committee for the National Institute for the Environment, www.cnie.org). The data available on the Internet is growing rapidly.20The environmental compliance records of more than 600 U.S. companies can be found at http://es.epa.gov/oeca/sfi/index.html. A catalog of U.S. Environmental Protection Agency documents can be found at http://www.epa.gov/ncepihom/catalog.html. Data on the toxic properties of chemicals can be found at toxnet.nlm.nih.gov and http://www.chemquik.com. Some of the exercises sample student attitudes. Others call for student projects in the lab or in the community. Some of the questions are open-ended in the sense that society has yet to find a good answer for them, but they leave room for dis- cussion. Those using this volume as a textbook will find field trips helpful. These might include visits to a solar house, a farm us- ing sustainable agriculture, a tannery, a plant manufacturing solar cells, etc. Although the course at the University of Delaware had no laboratory, one would be useful to familiarize students with techniques of green chemistry that they might not encounter in the regular courses. These might include the synthesis, characterization, and evaluation of a zeolite, running a reaction in an extruder, using a catalytic membrane reactor, adding ultrasound or microwaves to a reaction, making a chem- ical by plant cell culture, doing biocatalysis, making a compound by organic electrosynthesis, running a reaction in super- critical carbon dioxide, and use of a heterogeneous catalyst in a hot tube. Ideally, students would run a known reaction first, then an unknown one of their own choice (with appropriate safety precautions). Such a lab would require the collaboration of several university departments. There is a myth that green chemistry will cost more. This might be true if something was to be added at the smokestack or outlet pipe. However, if the whole process is examined and rethought, being green can save money. For example, if a pro- cess uses solvent that escapes into the air, there may be an air pollution problem. If the solvent is captured and recycled to the process, the savings from not having to buy fresh solvent may be greater than the cost of the equipment that recycles it. If the process is converted to a water-based one, there may be additional savings. It is hoped that many schools will want to add green chemistry to their curricula. Sections of this book can be used in other courses or can be used by companies for in-house training. The large number of references makes the book a guide to the lit- erature for anyone interested in a sustainable future. Albert S. Matlack REFERENCES 1. J. Lubchenko, Science, 1998, 279, 491. 2. (a) R. Goodland and H. Daly. Ecol. Appl., 1996,6, 1002. (b) A. Merkel, Science, 1998, 281: 336. 3. A.S. Matlack, Green Chem, 1999, 1(1): G17. 4. J.E. Andrews, P. Brimblecombe, T.D. Jickells, P.S. Liss, eds. Introduction to Environmental Chemistry. Blackwell Science, Cam- bridge, MA 1995. Preface v 5. C.L. Baird, Environmental Chemistry, W.H. Freeman, New York, 1995. 6. D.G. Crosby, Environmental Toxicology and Chemistry, Oxford University Press, New York, 1998. 7. R.S. Gupta, Environmental Engineering and Science: An Introduction, Government Institutes, Rockville, MD, 1997. 8. D.L. Macalady, Perspectives in Environmental Chemistry, Oxford University Press, Oxford, England, 1997. 9. S.E. Manahan, Environmental Chemistry, 6th ed., Lewis Publishers, Boca Raton, FL, 1994; Fundamentals of Environmental Chem- istry, Lewis Publishers, Boca Raton, FL, 1993. 10. T.C. Spiro, W.M. Stigliani, Chemistry of the Environment, Prentice Hall, Upper Saddle River, NJ, 1996. 11. J. Clark, Chem Br, 1998, 34(10): 43. 12. (a) B. Hileman, Chem Eng News, July 20, 1998, 41; (b) J. Darmstadter, Chem Eng News, August 10, 1998, 6; (c) N.E. Gallopou- los, Chem Eng News, August 10, 1988, 7; (d) T.E. Graedel, B.R. Allenby, Industrial Ecology, 1995; Design for Environment, 1996; Industrial Ecology and the Automobile, 1996, all from Prentice Hall, Paramus, NJ. (e) B.R. Allenby, Industrial Ecology: Policy Framework and Implementation, Prentice Hall, Paramus, NJ, 1998. 13. A.W. Gessner, Chem. Eng. Prog., 1998, 94(12), 59. 14. (a) Anon., Preprints ACS Div. Environ Chem, 1994, 34(2), pp. 175–431. (b) P.T. Anastas, C.A. Farris, eds. Benign by Design: Al- ternative Synthetic Design for Pollution Prevention, ACS Symp. 577, Washington, D.C., 1994; (c) P.T. Anastas, T.C. Williamson, eds. Green Chemistry: Designing Chemistry for the Environment, ACS Symp 626, Washington, D.C., 1996; (d) S.C. DeVito, R.L. Garrett, eds. Designing Safer Chemicals: Green Chemistry for Pollution Prevention, ACS Symp. 640, Washington, D.C., 1996; Chemtech, 1996, 26(11):34. (e) J.J. Breen, M.J. Dellarco, eds. Pollution Prevention in Industrial Processes: The Role of Process An- alytical Chemistry, ACS Symp. 508, Washington, D.C., 1994. (f) P.T. Anastas, T.C. Williamson, eds. Green Chemistry: Frontiers in Benign Chemical Syntheses and Processes, Oxford University Press, Oxford, England, 1998. 15. (a) W. Buchner, R. Schliebs, G. Winter, K.H. Buchel, Industrial Inorganic Chemisty, VCH, Weinheim, 1989; (b) K. Weissermel, H.-J. Arpe, Industrial Organic Chemistry, 3rd ed., VCH, Weinheim, 1997. (c) P.J. Chenier, Survey of Industrial Chemistry, 2nd ed., VCH, Weinheim, 1992; (d) H. Wittcoff, B. Reuben, Industrial Organic Chemicals, 2nd ed., John Wiley, New York, 1996; (e) J.I. Kroschwitz, ed. Kirk-Othmer Encyclo Chem Technol, 4th ed., John Wiley, 1991; (f) J.I. Kroschwitz, ed. Encyclo Polymer Sci and Eng, 2nd ed., John Wiley, New York, 1985–1989; (g) W. Gerhartz, ed., Ullmann’s Encyclo Ind Chem, 5th ed., VCH, Weinheim, 1985. 16. J. Haber, Pure Appl Chem, 1994, 66: 1597 17. (a) J.N. Armor, Environmental Catalysis, A.C.S. Symp. 552, Washington, D.C., 1993; (b) G.W. Parshall, S.D. Ittel, Homogeneous Catalysis, 2nd ed. John Wiley, New York, 1992; (c) B.C. Gates, Kirk-Othmer Encyclo Chem Technol, 4th ed., 1993, 5, 320; (d) W.R. Moser, D.W. Slocum, eds., Homogeneous Transition Metal-Catalyzed Reactions, Adv Chem 230, American Chemical Society, Washington, D.C., 1992; (e) J. P. Collman, L. S. Hegedus, Principles and Applications of Organotransition Chemistry, University Science Books, Mill Valley, CA, 1980; (f) C. Elschenbroich, A. Salzer, Organometallics—A Concise Introduction, VCH, Weinheim, 1992; (g) G. Braca, Oxygenates by Homologation or COHydrogenation with Metal Complexes, Kluwer Academic Publishers, Dor- drect, The Netherlands, 1994; (h) F.P. Pruchnik, Organometallic Chemistry of the Transition Elements, Plenum, NY, 1993. 18. (a) J. Tolgyessy, ed., Chemistry and Biology of Water, Air, Soil—Environmental Aspects, Elsevier, Amsterdam, 1993; (b) B. Evan- gelou, Environmental Soil and Water Chemistry, Wiley, NY, 1998. 19. A. Kumar, R. Desai, R. Kumar, Environ. Prog., 1998, 17(2), S11. (gives a directory of World Wide Web sites) 20. (a) S.M. Bachrach, ed., The Internet: A Guide for Chemists, American Chemical Society, Washington, D.C., 1996; (b) T. Murphy, C. Briggs-Erickson, Environmental Guide to the Internet, Government Institutes, Rockville, MD, 1998; (c) K. O’Donnell, L. Winger, The Internet for Scientists, Harwood, Amsterdam, 1997; (d) L.E.J. Lee, P. Chin, D.D. Mosser, Biotechnol. Adv., 1998, 16: 949; (e) B.J. Thomas,The World Wide Web for Scientists and Engineers, SAE International, Warrendale, PA, 1998; (f) S. Lawrence, C.L. Giles, Science, 1998, 280: 98; (g) R.E. Maizell, How To Find Chemical Information: A Guide for Practicing Chemists, Edu- cators and Students, Wiley, NY, 1998. Contents Preface iii 1. INTRODUCTION 1 I. General Background 1 II. Toxicity of Chemicals in the Environment 2 III. Accidents with Chemicals 6 IV. Waste and Minimization 13 V. Conclusions 18 VI. Summary of Some Important Points 19 References 20 Recommended Reading 25 Exercises 25 2. DOING WITHOUT PHOSGENE 27 I. Introduction 27 II. Preparation of Isocyanates 28 III. Polycarbonates 39 IV. Summary and Conclusions 39 References 42 Recommended Reading 45 Exercises 45 3. THE CHLORINE CONTROVERSY 47 I. The Problem 47 II. Toxicity of Chlorine Compounds 50 III. Estrogen Mimics 51 IV. Bleaching Paper 52 V. Disinfecting Water 53 VI. Chlorofluorocarbons and Ozone Depletion 54 VII. Chlorinated Solvents 57 VIII. Syntheses Where the Chlorine Is Not in the Final Product 58 vii viii Contents IX. Summary and Conclusions 60 References 61 Recommended Reading 66 Exercises 66 4. TOXIC HEAVY METAL IONS 67 I. The Problem 67 II. End-of-the-Pipe Treatments 70 III. Biocides 72 IV. Catalysts for Reactions Other than Oxidation 74 V. Dyes and Pigments 75 VI. Electrical Uses 76 VII. Leather 77 VIII. Metal Finishing 77 IX. Oxidation 78 X. Miscellaneous 94 References 94 Recommended Reading 101 Exercises 101 5. SOLID CATALYST AND REAGENTS FOR EASE OF WORKUP 101 I. Introduction 103 II. The Use of Inorganic Supports 105 III. Ion-Exchange Resins 114 IV. Combinatorial Chemistry 118 V. Other Uses of Supported Reagents 120 VI. Cyclodextrins 126 References 128 Recommended Reading 135 Exercises 135 6. SOLID ACIDS AND BASES 137 I. Introduction 137 II. Polymeric Sulfonic Acids 138 III. Polymer-Supported Lewis Acids 139 IV. Sulfated Zirconia 140 V. Supported Metal Oxides 141 VI. Rare Earth Triflates 141 VII. Solid Bases 144 VIII. Zeolites and Related Materials 145 IX. Clays 155 X. Heteropolyacids 159 References 163 Recommended Reading 173 Exercises 173 7. CHEMICALSEPARATIONS 175 I. The General Picture 175 II. Inclusion Compounds 178 Contents ix III. Separation of Ions 182 IV. Membrane Separations 185 References 192 Recommended Reading 200 Exercises 200 8. WORKING WITHOUT ORGANIC SOLVENTS 201 I. Advantages and Disadvantages of Solvents 201 II. Working Without Solvents 203 III. Reactions in Extruders 207 IV. Carbon Dioxide as a Solvent 210 V. Water as a Reaction Medium 214 VI. Surfactants and Cleaning 220 VII. Coatings 223 References 228 Recommended Reading 229 Exercises 229 9. BIOCATALYSIS AND BIODIVERSITY 241 I. Biocatalysis 241 II. Biodiversity 267 References 275 Recommended Reading 288 Exercises 288 10. STEREOCHEMISTRY 291 I. The Importance of Optical Isomers 291 II. The Chiral Pool 292 III. Resolution of Racemic Mixtures 295 IV. Asymmetric Synthesis 301 References 314 Recommended Reading 318 Exercises 318 11. AGROCHEMICALS 319 I. The Nature and Use of Agrochemicals 319 II. Problems with Agrochemicals 322 III. Alternative Agriculture 326 IV. Lawns 345 V. Genetic Engineering 346 VI. Integrated Pest Management 347 References 348 Recommended Reading 358 Exercises 358