Using Green Star Metrics To Optimize the Greenness of Literature Protocols for Syntheses

摘要

A procedure to improve the greenness of a synthesis, without performing laboratory work, using alternative protocols available in the literature is presented. The greenness evaluation involves the separate assessment of the different steps described in the available protocols reaction, isolation, and purification as well as the global process, with the tool green star. This proved to be adequate to assess separately the microgreenness of the steps. Two case studies, the syntheses of ethyl acetate and manganese(III) acetylacetonate, are presented. The results show how the different steps limit the global greenness of the synthesis and suggest that the workup may be more problematic than the reaction itself. Moreover, the study showed that the green star can be used for comparing in detail the alternative protocols proposed for a synthesis, finding the best alternative for each step and allowing the design of a greener protocol by combining them.