Andrew P. Dicks

Green chemistry teaching in higher education: a review of effective practices

This account reviews published green chemistry teaching resources in print and online literature and our experiences in teaching the subject to undergraduate students. Effective practices in lecture and laboratory are highlighted and ongoing challenges are addressed, including areas in cutting edge green chemistry research that impact its teaching in the undergraduate curriculum. In particular, the influence of green chemistry on the overall teaching of organic chemistry is discussed.

A review of aqueous organic reactions for the undergraduate teaching laboratory

Abstract This article summarizes the wide scope of aqueous organic reactivity from a pedagogical perspective. It is aimed at university instructors with the goal of promoting water as a solvent in academic institutions. Recently, extensive industrial and scholarly research has concerned development of organic reactions in aqueous media. Many examples are now possible in the student laboratory including carbon–carbon/carbon–nitrogen bond-forming reactions and functional group transformations (e.g. oxidations, reductions, and halohydrations). Experiments are summarized from the educational literature (journal articles and laboratory textbooks) and their green features are described. Using water as solvent often promotes significant rate enhancements and operational simplicity – both of importance when training undergraduates during limited laboratory time. Environmental benefits of using water are additionally highlighted to students’ first hand in relation to the Twelve Principles of Green Chemistry.

An Introduction to Life Cycle Assessment

An introduction to the history of life cycle assessment (LCA) is provided as a segue into a more detailed presentation of the guidelines and principles of LCA. The term “life cycle” is defined and illustrated by means of a figure which is used to describe various system boundaries that a typical LCA can evaluate. Discussion then shifts to the four stages of the LCA process identified in the international standards for conducting a life cycle analysis. These principles are connected with the principles of green chemistry in order to highlight common goals related to both fields. The theoretical portion ends with a discussion of the virtues and limitations inherent in the currently accepted methodology. This section covers the notion of “burden shifting” as well as the complexity and arbitrary nature of several components of the LCA process. The use of software packages to simplify LCA is described in the context of an approach developed at GlaxoSmithKline known as Fast Life Cycle Assessment of Synthetic Chemistry (FLASCTM). The advantages of this software are explored by revisiting the synthesis of 7-aminocephalosporanic acid. The chapter concludes with a novel approach to teaching LCA in the context of green metrics to upper-level undergraduate students.

Solvent-free reactivity in the undergraduate organic laboratory

Abstract This review highlights progress made since 2000 in the development of solvent-free organic reactions for student use. It is directed at university instructors to illustrate the broad scope of solventless reactivity possible in undergraduate laboratories. Eliminating a reaction medium directly addresses the Twelve Principles of Green Chemistry and is a focal point of contemporary industrial research. Experimental conditions are straightforward to implement and include reactant grinding, room temperature stirring, microwave irradiation, and conventional heating. A wide range of functional group transformations is easily achievable. Solvent-free reactions are often complete in a matter of minutes and routinely require simplistic work-up and purification protocols. Procedures are compiled from educational resources (primarily pedagogical journals and laboratory manuals) and corollary green experimental elements emphasized where possible.

Green Chemistry Metrics

This chapter provides an overview of green metrics and their historical role in promoting the development of green chemistry. Starting with the history of the field, the Twelve Principles of Green Chemistry are introduced and discussed in conjunction with a “green-by-design” approach recently applied to the synthesis of Lipitor. Various perspectives on synthetic efficiency are briefly outlined with reference to atom economy and E factor. These ideas are further explored in the context of three industrial processes which have received Presidential Green Chemistry Challenge Awards. The synthesis of ibuprofen is examined from the point of view of intrinsic efficiency. Using the BHC process as an example, several benefits associated with the use of catalysis are discussed, with an emphasis placed on designing atom-efficient reactions. A global perspective centered around the production of chemical waste is also outlined with reference to Merck’s commercial synthesis of Januvia, a medication for the treatment of type II diabetes. Finally, Pfizer’s new sertraline process is used to describe ways of improving both quantitative as well as qualitative aspects of an industrial synthesis. The chapter concludes with a brief outline of the future directions of green metrics.

The EcoScale as a framework for undergraduate green chemistry teaching and assessment

ABSTRACT An upper-year undergraduate practical examination is presented that utilizes the EcoScale (a semi-quantitative tool) and several established mass metrics to assess student understanding of green chemistry principles. This activity focuses on the straightforward preparation of a benzodiazepine via three different catalytic methods, and the analysis of individual experimental data during laboratory time. Students learn about the structure of the EcoScale, apply it as a simplistic life cycle assessment, and critique it as a scientific model. The examination complements more traditional expository and self-design experiments within a synthetic course where green chemistry and sustainability are central themes. GRAPHICAL ABSTRACT

Atom Economy and Reaction Mass Efficiency

The green metrics atom economy (AE) and reaction mass efficiency (RME) are introduced and discussed. Following literature definitions, examples of reactions appropriate for upper-level undergraduate students are provided to illustrate how the metrics are calculated. In the case of atom economy, important assumptions regarding reactants, solvents and reagents are identified and explained. Several examples of inherently atom-efficient and inefficient reactions are also provided. In terms of reaction mass efficiency, the focus centers on a concise mathematical breakdown of various factors which contribute to changes in RME values in the context of two well-established definitions. A view of RME as a more robust metric that better captures the materials used during a chemical transformation is developed in the context of an undergraduate Suzuki reaction. With numerous academic and industrial examples comparing traditional syntheses with modern catalytic routes, the benefits and limitations of AE and RME are considered. Along with real-world case studies, the useful and effective application of these metrics is explained using several definitions of an ideal chemical reaction as points of reference. Finally, future projections and academic work are briefly outlined in order to highlight the development of these important metrics.

Selected Qualitative Green Metrics

Qualitative green metrics such as the laboratory EcoScale, its modified industrial form and other computational tools are discussed. The first half of the chapter provides the reader with an appreciation of point-based categorical analysis as a means of assessing process greenness. Using calculated values for two benzodiazepine preparations, the EcoScale approach is explained in terms of its virtues and limitations. Simplicity and flexibility are highlighted as key advantages which make the EcoScale particularly effective in evaluating the nature of process operations and materials. Discussion then shifts to a recently proposed modified version of the EcoScale which addresses several drawbacks inherent in the original method. Using a newly defined system based on rewards rather than penalties, the modified EcoScale is shown to be effective at assessing industrial processes. The second portion of the chapter discusses two additional qualitative methods which are based on computational analysis. These approaches are the environmental assessment tool for organic syntheses (EATOS) and the radial polygon approach proposed by Andraos. To highlight their illustrative power and comprehensive scope, a recent article comparing four routes to a cyclic carbamate product is considered.

CHAPTER 11:The State of Green Chemistry Instruction at Canadian Universities

This chapter summarizes some of the important green chemistry teaching initiatives currently in place at the Canadian post-secondary education level. It presents examples taken from several Canadian universities currently offering undergraduate courses and/or laboratory instruction involving green principles. Relevant syllabi are compared and contrasted to provide a perspective on what is being taught and how, along with materials published by authors at Canadian institutions in the field of green chemistry education. Student and instructor feedback is additionally provided as appropriate. Potential future directions in green chemistry are also discussed.

Green Chemistry and Associated Metrics

This chapter provides an overview of green metrics and their historical role in promoting the development of green chemistry. Starting with the history of the field, the Twelve Principles of Green Chemistry are introduced and discussed in conjunction with a “green-by-design” approach recently applied to the synthesis of Lipitor®. Various perspectives on synthetic efficiency are briefly outlined with reference to atom economy and E factor. These ideas are further explored in the context of three industrial processes which have received Presidential Green Chemistry Challenge Awards. The synthesis of ibuprofen is examined from the point of view of intrinsic efficiency. Using the BHC process as an example, several benefits associated with the use of catalysis are discussed, with an emphasis placed on designing atom-efficient reactions. A global perspective centered around the production of chemical waste is also outlined with reference to Merck’s commercial synthesis of Januvia®, a medication for the treatment of type II diabetes. Finally, Pfizer’s new sertraline process is used to describe ways of improving both quantitative as well as qualitative aspects of an industrial synthesis. The chapter concludes with a brief outline of the future directions of green metrics.