Alternative reaction conditions, Green Chemistry

Alternative reaction conditions. Green Chemistry, 132-175 Alternative syntheses characterization, 223-227 computer generation of synthesis routes, 215-218... 

The Future of Glycerol New Uses of a Versatile Raw Material 2 Alternative Solvents for Green Chemistry 3 Eco-Friendly Synthesis of Fine Chemicals 4 Sustainable Solutions for Modern Economies 5 Chemical Reactions and Processes under Flow Conditions 6 Radical Reactions in Aqueous Media... 

Keywords Green chemistry alternative feedstocks benign reagents catalytic synthetic pathways natural processes biocatalysis alternative solvents safer chemicals alternative reaction conditions minimization of energy consumption... 

Alternative Reaction Conditions. The conditions that are used in synthesizing a chemical can have a significant effect on the pathway s overall environmental impact. Considerations of the amount of energy us by one process versus another is quite easily evaluated in economic terms but is not currently as easily evaluated in environmental terms. It appears that because of this difficulty in measurement, and not necessarily as a judgement on relative importance, that the majority of Green Chemistry research on reaction conditions has been centered around the substances utilized as part of those conditions. 

Biocatalysis has many advantages in the context of green chemistry, e.g. mild reaction conditions and often fewer steps than conventional chemical procedures because protection and deprotection of functional groups are often not required. Consequently, classical chemical procedures are increasingly being replaced by cleaner biocatalytic alternatives in the fine chemicals industry (see later). 

Many of the traditional solvents that are favoured by organic chemists have been blacklisted by international regulations, for instance chlorinated hydrocarbon solvents have been severely curtailed. Thus, the question of the solvent requires a major rethink in terms of green chemistry issues this need is driving the search for alternative reaction media. Such media are the basis of many of the cleaner chemical technologies that have reached commercial development. Typical non-conventional reaction media are supercritical carbon dioxide (31.1 °C, 73 atm)22 and supercritical water (374 °C, 218 atm), water under PjT standard conditions, " room-temperature ionic liquids,up to and including solvent-free conditions. ... 

A great deal of the environmental concern associated with chemical manufacture comes from not merely the chemicals that are made or the chemicals from which they are made, but from all of the substances associated with their manufacture. In the manufacture, processing, formulation and use of chemical products, there are a variety of associated substances that contribute to the environmental loading from chemical manufacture. The most visible of these associated substances are the solvents used in reaction media, separations and formulations. Many solvents, especially the widely used volatile organic solvents, have come under increased scrutiny and regulatory restriction based on concerns for their toxicity and their contributions to air and water pollution. It is for these economic and environmental reasons that much of the research and development in Green Chemistry reaction conditions is focussed on alternative solvents. 

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