Green Chemistry Metrics - Comparison of Metrics

Comparison of Metrics

A group of scientists at GSK attempted to compare the metrics currently available, with the goal of designing a metric set suitable for their business. Following lengthy comparisons of different metrics for twenty eight reaction types and comparing simple and complex costings for four different drug molecules, they came up with a number of conclusions. It was suggested that yield is still a very good metric especially for high value added chemistries such as those used in pharmaceutical synthesis, but conceded that yield does not encourage sustainable practices. Atom economy has its uses in conjunction with other metrics but is not suitable as a standalone green chemistry metric. Reaction mass efficiency combines both process and chemistry features and thereby has potential to be used optimally by chemists, process chemists and chemical engineers. The reaction mass efficiency is more likely to encourage sustainable practices as it focuses attention away from the waste and towards the use of materials. However, in terms of measuring the process and ease of use E-factors are the most effective calculation at the current time.