Book and Media Review pubs.acs.org/jchemeduc
Review of Green Organic Chemistry in Lecture and Laboratory Mary M. Kirchhoff* Education Division, American Chemical Society, Washington, D.C. 20036, United States Three chapters are devoted to solvent usage. Chapter 3 considers the “Elimination of Solvents in the Organic Curriculum”. A fundamental question is “What constitutes solvent-free?” The literature can be confusing, as some reactions claiming to be solvent-free use no additional solvent because the reactant serves as the solvent. The chapter presents academic and industrial examples that minimize solvent use, such as Eastman Chemical Company’s biocatalytic process to produce esters used in cosmetics. Eastman eliminated 10 L of organic solvent per kilogram of ester produced in a process that earned Eastman a 2009 Presidential Green Chemistry Challenge Award. Engineering approaches to solvent-free reactionssuch as spinning tube-in-tube reactors to synthesize ionic liquids; spinning disc reactors used in polymerization reactions; and a bubble column reactor to produce surfactantsare also explored. The chapter concludes by highlighting a variety of solvent-free reactions, including some that use an environmentally benign solvent during workup, which are appropriate for an introductory organic chemistry course. Chapter 4 continues the focus on solvents by exploring “Organic Reactions under Aqueous Conditions”. The author notes that green chemistry has helped to reawaken interest in the use of water as a benign solvent. Using water as a solvent requires careful consideration, however: Solubility and functional group compatibility must be taken into account, along with isolation of water-soluble products and treatment and disposal of the contaminated aqueous waste stream. Yet there can be advantages when water is the solvent because some reactions demonstrate enhanced selectivity and rate acceleration when conducted in water. Industrial applications employing aqueous chemistry are highlighted for use as potential case studies. Undergraduates are typically exposed to little industrial chemistry, and these examples serve to introduce students to industrial examples of greener processes. The final solvent-related chapter examines “Organic Chemistry in Greener, Non-Aqueous Media”. This chapter considers the use of nonorganic and nonaqueous solvents, including supercritical carbon dioxide, ionic liquids, fluorous solvents, and polymeric liquids. The author notes, “no procedure for an undergraduate laboratory involving a reaction in scCO2 has been published”, which is likely owing to the cost of the equipment needed for scCO2 experiments. Cost is also a factor in the dearth of undergraduate experiments using fluorous solvents. With respect to ionic liquids, the author correctly reports “it is inappropriate to classify all ionic liquids, and all reactions undertaken in ionic liquids, as green”. Some ionic liquids are highly toxic, while the environmental impact of manufacturing other ionic liquids is substantial. Several organic
Green Organic Chemistry in Lecture and Laboratory, edited by Andrew P. Dicks. CRC Press: Boca Raton, FL, 2011. 283 pp. ISBN: 978-1439840764 (hardcover). $157.95. Green Organic Chemistry in Lecture and Laboratory is a valuable compilation of classroom and laboratory examples suitable for undergraduate organic chemistry. This edited volume offers practical strategies for integrating green chemistry into existing courses, or designing a stand-alone course focused on green chemistry. The first chapter, “Introduction to Teaching Green Organic Chemistry”, presents the 12 principles of green chemistry in the context of teaching organic chemistry. The author points out some of the nuances associated with green chemistry metrics; for example, while the E-factor enables students to quantify the amount of waste produced, it says nothing about the nature of that waste. This introductory chapter cites a number of education resources that facilitate undergraduate teaching from a green chemistry perspective.
Cover image provided by CRC Press and reproduced with permission.
Chapter 2 details the challenges associated with “Designing a Green Organic Chemistry Lecture Course”. The advantages and disadvantages of greening an existing course versus creating a new course are outlined, and the author describes his experiences using the latter approach in teaching an Industrial and Green Chemistry course. One of the major challenges associated with the introduction of green chemistry into the organic chemistry curriculum is the absence of balanced equations in organic chemistry. The author argues that balancing chemical equations in the second-year organic chemistry course “will go a very long way in vastly improving students’ conceptual understanding of reactivity and reaction mechanisms”. © XXXX American Chemical Society and Division of Chemical Education, Inc.
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Book and Media Review
and Laboratory is a useful reference book that will assist faculty in fostering these skills in their students.
labs involving the synthesis and use of ionic liquids are featured. Chapter 5 concludes by highlighting the potential of several promising solvents, such as ethyl-L-lactate, 2-methylhydrofuran, pinene, and switchable solvents. “Environmentally Friendly Organic Reagents” is the topic of Chapter 6, which covers a range of greener reagents suitable for the undergraduate organic laboratory. For example, a number of procedures have been published that employ household bleach as the oxidizing agent in converting alcohols to ketones and ketones to carboxylic acids. Environmentally preferable reducing agents for carbonyl compounds include biological reagents, such as Baker’s yeast and carrots. Nonbiological alternatives to traditional reducing agents, such as lithium aluminum hydride and sodium borohydride, can involve more complex systems. Despite the availability of these alternatives, the author notes that sodium borohydride remains the most versatile reagent for reducing carbonyl compounds in the undergraduate laboratory. The use of metal catalysts in the undergraduate organic laboratory has grown in recent years, as evidenced by experiments focused on alkyne coupling, metathesis reactions, and epoxide ring opening. The breadth of greener reagents available should promote an exploration of reagents currently in use in the undergraduate teaching laboratory with an eye toward potential substitutions. Chapter 7 is the one chapter that seems out of place in the text because “Organic Waste Management and Recycling” typically do not fall under the purview of green chemistry. The author does, however, note, “[C]reating awareness of chemical waste management and recycling at the undergraduate level is demonstrably of utmost importance.” Strategies, such as microscale chemistry and quantification of all reaction components, for helping undergraduates identify and reduce waste are presented. Because a waste-free undergraduate organic chemistry laboratory does not currently exist, disposal protocols are described for different categories of waste commonly found in the organic teaching laboratory, along with examples of reagent and solvent recycling. The chapter concludes with a section on recycling consumer and natural products. The final chapter looks at “Greener Organic Reactions under Microwave Heating”. Advantages of using microwave heating may include accelerated reaction rates, higher yields, fewer side products, and decreased solvent use. The author provides practical information and guidance on multimode and monomode microwave ovens, reminding the reader that technical support on the part of the manufacturer is an important consideration when purchasing a laboratory-grade microwave oven. The chapter concludes with a number of experiments suitable for the undergraduate laboratory; classic reactions conducted under microwave conditions include the Williamson ether synthesis, the Wittig reaction, transition metal-catalyzed reactions, heterocyclic synthesis, oxidations, and reductions. The appendix includes entries for 178 reactions cited in the book and categorized by reaction type, techniques, and green chemistry principles. The appendix, coupled with the wellreferenced chapters, makes it easy for faculty to access the primary literature for the exemplars highlighted throughout the text. Educating students about environmentally friendly alternatives to traditional solvents, reagents, and reaction conditions fosters critical thinking and promotes sustainability through green chemistry. Green Organic Chemistry in Lecture
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AUTHOR INFORMATION
Corresponding Author
*E-mail: m_kirchhoff@acs.org.
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