Book Review of Catalysis: Concepts and Green Applications, 1st Edition

Jan 12, 2010 - rence in the environment, their ecotoxicity, and efforts to remove ... difficult to make broad generalizations about PPCPs, as detec- ...
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Chemical Education Today edited by

Cheryl Baldwin Frech University of Central Oklahoma Edmond, OK 73034-5209

Pharma-Ecology: The Occurrence and Fate of Pharmaceuticals and Personal Care Products in the Environment by Patrick K. Jjemba Wiley & Sons: Hoboken, NJ, 2008. 314 pp. ISBN 978-0470046302. $99.95 reviewed by Carl P. Fictorie

As the title suggests, pharma-ecology is a discipline focusing on the fate, roles, and effects of pharmaceuticals and personal care products (PPCPs) in the environment. “This book is intended to examine the usage of these chemicals, their occurrence in the environment, their ecotoxicity, and efforts to remove them from various matrices in the environment” (p 2). In doing so, the author is among the first to bridge the gap between medicine and environmental science. The book argues that there is a minimal understanding of the effects of PPCPs on plants and animals exposed to low levels of these compounds. PPCPs function as contaminants in natural systems, and the resulting ecological effects are poorly understood. One major theme of the book is that PPCPs, particularly prescription drugs, often enter the wastewater stream unaltered from their parent form. Wastewater treatment fails to completely remediate the PPCPs, thus, letting them enter surface waters. Among the biggest challenges is the wide array of PPCPs, each with unique chemical and physical properties. It is therefore difficult to make broad generalizations about PPCPs, as detection, ecotoxicity, and remediation are often unique to the specific compound. Chapter 1 classifies PPCPs broadly into personal care products (fragrances, detergents, and disinfectants) and pharmaceutical compounds; the latter are further classified by medicinal use. Tables of compounds are extensive and detailed, and many examples of specific compounds are used. Some understanding of biochemistry or physiology would aid the reader's understanding of details. Data on the usage of prescription drugs are provided. Unfortunately, these data are in the form of numbers of prescriptions rather than of mass or volume produced, so one can only estimate the total output of pharmaceuticals. Analysis and occurrence of PPCPs is the subject of Chapter 2. The first section gives an overview and examples of detection methods. This part will disappoint chemistry instructors because it provides few details, largely because the analytical method is usually specific to the system. The rest of the chapter provides considerable data on the occurrence of PPCPs in wastewater, surface water, groundwater, potable water, sediments, soils, and aerial environments. The data presented are somewhat eclectic, but they adequately illustrate the author's point that PPCP contamination is widespread. It is in this context that the author states one of the book's major themes: “excretion [by humans and animals] of pharmaceuticals is the major route by which [pharmaceuticals] are introduced into the environment” (p 112). 144

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In Chapter 3, the author uses the principles of pharmacology to analyze the fate of PPCPs in the environment. Mathematically based principles such as absorption and elimination rates, half-life, and clearance have equivalent roles within environmental systems. Some concepts will be unfamiliar to those not versed in pharmacokinetics, and many equations are not explained adequately. The rest of the chapter discusses degradation pathways of PPCPs, with some examples describing degradation products in terms of specific compounds or classes of compounds. Chapter 4 surveys the ecotoxicity of PPCPs. As the author notes, despite extensive testing of PPCPs for toxicity with respect to the organisms in which they are used, there is far less testing and little understanding of their effect on organisms for which they were not designed. Antibiotic resistance is addressed, with a prominent discussion of the challenges of assessing the impact of long-term, low-level exposure to PPCPs. Wastewater treatment, the subject of Chapter 5, is included because of the significant contribution of excreted pharmaceuticals to the wastewater stream. In line with the theme that PPCPs are heterogeneous, wastewater treatment varies widely in its effectiveness toward different classes of PPCPs. Primary and secondary treatment technologies, which are intended to remove solid particles and dissolved organic matter, do not remove some PPCPs or carry them out as adsorbed species on sludge. In the latter case, PPCPs can be released into the environment where the sludge is deposited. The chapter is devoted to advanced treatment methods, discussing advanced filtration, chemical oxidation processes, UV treatment, and electrolysis, with examples of which methods are suited for different classes of PPCPs. The last chapter describes various policy-level methods and meta-analysis tools to provide lifecycle or cradle-to-cradle approaches for addressing the problem of PPCPs in the environment. The author praises the value of PPCPs to modern society but advocates for a broader range of analysis and understanding so that environmental concerns and unintended consequences can be minimized. In this context, he also emphasizes the need of medical practitioners to evaluate the environmental consequences of medical treatment options as a factor in the choice of treatment. The book claims to cover all types of PPCPs. Unfortunately, there is little discussion of personal care products beyond Chapter 1. This probably reflects the state of knowledge: there is more information regarding pharmaceuticals than personal care products. The extensive references to the primary literature from many fields are a good resource; coupled with the comprehensive index, the book will be a valuable resource. Interested readers might also find the review by G. B. Kauffman in Chem. Eng. News (1) of further value. The author has taken on the daunting task of describing the environmental fate of the whole range of PPCPs in broad perspective. He has done a good job of it. The book's wide scope means that only selected details can be provided, but this is complemented by the extensive list of references. The author provides several well-written introductions, transitions between sections, and chapter conclusions that tie the book together.

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Chemical Education Today

This book will be a valuable resource to an academic library, either graduate or undergraduate, and provides numerous examples for instructors of environmental chemistry and health-related chemistry courses. Literature Cited 1. Kauffman, G. B. Chem. Eng. News 2008, 86 (50), 36–37.

Carl P. Fictorie is a member of the Department of Chemistry, Dordt College, Sioux Center, IA 51250-1606; [email protected]. DOI: 10.1021/ed800069g Published on Web 01/12/2010

Catalysis: Concepts and Green Applications, 1st Edition by Gadi Rothenberg Wiley-VCH Verlag GmbH & Co. KGaA : Weinheim, Germany. 2008. 279 pp. ISBN 978-3527318247 (cloth); $80.00 reviewed by John H. Shibata

“This introductory textbook covers all aspects of catalysis.” This sentence on the back cover of Catalysis: Concepts and Green Applications summarizes the book's contents but understates the book's usefulness as a resource for both teachers and students. This succinct, well-written book includes numerous examples and references of catalysis research, ranging from industrial applications to computational methods. Everything about this book is reader-friendly, from the well-designed figures and the use of color to the complete titles in the references. The writing is crisp and engaging, with morsels of historical facts and details scattered throughout the text. Adopting a textbook format, Catalysis has six chapters. Each chapter ends with several exercises and references. To aid in using this book for teaching, there is a Web site, http://www. catalysisbook.org/, which contains ancillary materials that have become expected supplements for textbooks. For example, lecture slides for each chapter include not just figures and equations from the book, but also additional diagrams and photographs. Answers to selected exercises are also included on the Web site. One outstanding feature of this site is a complete list of references from the textbook with digital object identifier (DOI) links that take you directly to the referenced paper. Chapter 1 places catalysis in the context of green chemistry and sustainable development. The chapter provides basic definitions of concepts such as atom economy and the 10 principles of green chemistry. It then offers a method for assessing how “green” a product or process is through conducting a qualitative analysis of its overall environmental impact, including energy demands, transportation costs, and waste from the raw materials to the finished product. An interesting exercise at the end of the chapter involves assessing the overall environmental impact of fluorescent versus incandescent light bulbs. The answer to the question of why catalysis is important in green chemistry begins r 2010 American Chemical Society and Division of Chemical Education, Inc.

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with the general concept of a catalyst as a substance that provides a faster reaction pathway without being consumed in the reaction. The author uses this concept as a means by which to introduce the different categories of catalysis: homogeneous, heterogeneous, and biocatalysis, and the tools for synthesizing, characterizing, and modeling catalysis. Chapter 2 provides an excellent calculus-based description of chemical kinetics that lays the foundation for the role of catalysis in facilitating chemical reactions. The chapter describes key concepts such as reaction orders, rate equations, reaction mechanisms, and rate-determining steps, but it omits detailed derivations to keep the book a reasonable length. Fortunately, the author's list of references for kinetics and other topics is outstanding. And, the chapter introduces Langmuir-Hinshelwood kinetics and Michaels-Menten kinetics in preparation for later discussions on heterogeneous catalysis and biocatalysis, respectively. The chapter's conclusion describes catalyst deactivation, an important consideration in practical applications of catalysis. In Chapter 3, the elementary steps of homogeneous catalysis are described in terms of six main categories: dissociation and coordination, oxidative addition, reductive elimination, insertion and migration, deinsertion and β-elimination, and nucleophilic attack on a coordinated substrate. A qualitative description of structure-activity relationships in homogeneous catalysis is then presented with detailed discussions of steric and electronic effects. Several industrial examples of homogeneous catalysis are presented, including the Wacker oxidation process for oxidizing olefins to carbonyl compounds, and the asymmetric synthesis of (S)-metolachlor. Reinforcing the connection to green chemistry, the chapter describes catalyst recovery and recycling and the role of catalysis in click chemistry. The click reaction Huisgen-type [3 þ 2] cycloaddition of azides and alkynes to triazoles is used to demonstrate the importance of improved reaction conditions and product selectivity in catalytic reactions. Chapter 4 concerns heterogeneous catalysis, beginning with the gas-solid catalysis system. Because a solid catalyst's surface is crucial to its performance, the chapter devotes several pages to types of solid catalysts and their preparation. High-temperature fusion, precipitation, and impregnation of porous supports are some of the preparation methods described. Once a catalyst is prepared, it must then be characterized. Several techniques for characterization of the solid catalyst are mentioned; these include X-ray diffraction, small angle scattering, X-ray photoelectron spectroscopy, electron microscopy, solid-state nuclear magnetic resonance spectroscopy, and infrared spectroscopy. The Langmuir equation and the Brunauer-Emmett-Teller equation are used to describe adsorption isotherms. The catalytic converter exemplifies a heterogeneous gas-solid catalytic system. Also discussed are liquid-solid and liquid-liquid catalytic systems, with a particular emphasis on aqueous systems. The chapter concludes by describing industrial catalytic systems, including the BP AVADA process for synthesizing ethyl acetate. This process won the 2002 AstraZeneca Award for Excellence in Green Chemistry and Engineering. Chapter 5 introduces biocatalysis with the goals of exploring industrial processes that use biocatalysis to manufacture chemicals and considering the future direction of biocatalysis in industry. Basic enzyme catalysis is introduced, and terms such as active sites and substrate binding are defined. Different types of industrial systems, such as whole-cell systems and enzymes immobilized in solid supports or sol-gel matrices, are described.

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The application of biocatalysis in industry has led to efforts toward the rational design and directed evolution of new biocatalysts. Examples from industry include the manufacture of aspartame using a thermolysin enzyme. Finally, Chapter 6, which concerns computer applications in catalysis research, describes the techniques and rationale for computer modeling of catalysts and catalytic cycles. One of the author's caveats regarding computer applications cannot be stressed enough: “The fact that a program did not crash does not mean that the results are meaningful” (p 232). The applicability of both classical molecular modeling (MM) and quantum mechanical (QM) modeling is discussed, with a brief example of the hybrid QM-MM method for modeling catalyst-substrate interactions. Descriptions and examples of not just the MM methods of molecular dynamics and Monte Carlo method, but also the QM methods of Hartree-Fock and density functional theory are given. One novel application of computer modeling is toward catalyst optimization: that is to say, rational catalyst design. The factors that must be considered in designing a catalyst include different catalyst structures, descriptors of each catalyst structure, and the catalyst's figures of merit, such as

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turnover number, turnover frequency, and price. The book then describes the method by which one translates these attributes mathematically so that a catalyst's design can be programmed. One caveat for readers: the topics in this chapter are best suited for those with a good background in physical chemistry and mathematics. In summary, the author's approach to catalysis from the perspective of green chemistry should appeal to a broad audience of scientists in chemistry, chemical engineering, and environmental science. I especially recommend this book to those teaching catalysis to advanced undergraduates and graduate students. The organization of topics, exercises, and ample references should provide students and teachers not just with an excellent textbook but also with resources beyond the classroom. John H. Shibata is a member of the Department of Chemistry, University of the South, Sewanee, TN; [email protected]. DOI: 10.1021/ed8000705 Published on Web 01/12/2010

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