To overcome health and environmental problems at the source, the chemical industry must develop cleaner chemical processes by the design of innovative and environmentally benign chemical reactions. Green chemistry offers the tools for this approach.1
Green organic syntheses must meet, if not all, at least some of the following requirements: avoid waste,2 be atom efficient,3 avoid the use and production of toxic and dangerous chemicals, produce compounds that perform better or as well as existing ones and are biodegradable, avoid auxiliary substances (e.g., solvents) or use eco-compatible solvents (water or dense CO2), reduce energy requirements, use renewable materials, and use catalysts rather than stoichiometric reagents.4
To focus on the more specific area of the replacement of harmful and undesirable compounds, a relevant case is given by methyl halides (CH3X, X = I, Br, Cl), dimethylsulfate (DMS), and phosgene (COCl2), which are reagents used for methylation and carbonylation reactions, respectively. For instance, Scheme 4.1 shows the methylation of phenol by CH3X and DMS to give anisole, and the alkoxycarbonylation of an alcohol by COCl2. These toxic and waste-producing reagents have a valuable green alternative in dimethylcarbonate (DMC).
Methods and Reagents for Green Chemistry: An Introduction, Edited by Pietro Tundo, Alvise Perosa, and Fulvio Zecchini
Copyright © 2007 John Wiley & Sons, Inc.
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