Environmental chemists toolbox

It is clear from the examples in this book that the use of biocatalysis can produce some very cost-effective and environmentally acceptable processes, and the authors anticipate that the use of this technology will increase as synthetic organic chemists realize its value and begin to look for strategic disconnections in the synthetic sequence of new target molecules where a biocatalytic step can be applied to utmost benefit. Thus, biocatalysis should be seen as a routine part of the synthetic toolbox and, in some cases, the reagent of choice for transformations such as the reduction of ketones to chiral alcohols, and not as a technology of last resort when all else has failed. 

Possibly the least explored and newest options available to the green chemist are liquid polymer solvents (Chapter 8) and switchable and tunable solvents (Chapter 9). Unreactive low molecular weight polymers or those with low glass transition temperatures can be used as non-volatile solvents. In particular, poly(ethyleneglycols) and poly(propyleneglycols) have been used recently in a range of applications. Probably the most important recent additions to our toolbox are switchable solvents. New molecular solvents have been discovered that can be switched from non-volatile to volatile or between polar and nonpolar environments by the application of an external stimulus. Gas-expanded liquids will also be discussed in Chapter 9, as carbon dioxide can be used as a solubility switch and to reduce the environmental burden of conventional solvents. 

Computational chemistry can play a key role in advancing the scientific enterprise. It can provide the data input for many larger, more complex models and provide us with unique insights into molecular behavior so that we can design and construct new molecules for specific tasks. Computational chemistry has become an established tool in the chemist s toolbox and is being used in broad areas of chemistry to replace experimental measurements and to provide us with improved understanding of molecular behavior. Computation will be the major tool that will enable us to cross the many temporal and spatial scales that characterize environmental science. 

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