Green Chemistry Considerations

The notions of mass balance, selectivity and conversion (see Figure 1.6) need to be added to the idea of yield when chemists consider a chemical transformation, particularly if this consideration takes place in the context of pollution prevention or green chemistry. ... 

A framework for designing safer chemicals using the concepts of green chemistry has been described. The framework is comprehensive because it expands the consideration of hazard... 

A common definition of green chemistry, which clearly encompasses considerable chemical engineering as well, is the design, development and implementation of chemical processes and products to reduce or eliminate substances hazardous to human health and the environment, (P. T. Anastas and J. Warner, Green Chemistry Theory and Practice, Oxford University Press, Oxford, 1998). A more recent article expands this definition to twelve principles (M. Poliakoff, J. M. Fitzpatrick, T.R. Farren and P.T. Anastas, Science, 297, 807-810 (2002). 

The progress of Green Chemistry impacts the established scenarios for the chemical industry (98,99). Future catalysts will likely become more enzyme-like in the sense that they will more efficiently balance the properties of effectiveness and fragility. An overarching environmental consideration holds a synthetic catalyst should simply go away by some mechanism when its work is done. Nature has developed enzymes with limited lifetimes. After their task is completed, their constituent molecules and atoms become recyclable to serve as useful resources for the... 

What, then constitutes an appropriate solvent for green chemistry Fundamentally, it must be a solvent which allows the chemist to accomplish his or her task, but in an environmentally conscious manner. The modem chemist is expected to consider toxicity as part of the key elements affecting choice of solvents, so that they are minimally toxic to human health and the environment, and disposed of in ways that do not contribute to pollution (DeVito, 1996). The considerations for what constitutes a safe solvent might contain some of the following considerations ... 

To determine how best to present green chemistry to students, it would be best to look at attitudes. A study reports on the relationship between attitudinal factors and student academic success in first-year chemistry courses. The study includes a comparison of attitudes toward chemistry of first-year medical students at two universities. Students from these two institutions differ considerably with respect to educational backgrounds. In the investigation, attitudes toward science (particularly chemistry) were correlated not only with students academic achievement, but also with personal demographic data, such as matriculation results, parents educational level, and location of high school. The students responses to an opinion survey suggest a substantial relationship between attitudes and academic achievement. The results also suggest that academic achievement in chemistry is more dependent on attitudes toward science than aptitudes of students (Cukrowska et al., 1999). 

It is important to reiterate that although minimization of human toxicity should be a major consideration in the design of any new chemical, it is by no means the only consideration. The ideal chemical should embody all aspects of green chemistry, not just reduced human toxicity. These other aspects are not discussed in this chapter, but are listed in Box 1.1. Other chapters in this book cover some of these other features, and other books in this Green Chemistry series cover many of the other features listed in Box 1.1. While developing that fully ideal chemical in many cases will be elusive, when designing new chemicals it is important that the chemist strive to incorporate all of the characteristics in Box 1.1. 

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