Developing environmentally-sound processes in the chemical industry: a case study on pharmaceutical intermediates

Life cycle assessment (LCA) is a widely accepted tool to quantitatively estimate environmental impacts of products or services. In this study, the LCA method has been applied to enantioselective reductions frequently used in synthetic chemistry. From these case studies three conclusions have been drawn. First, the environmental impacts as quantified by the method EcoIndicator 95 of biotechnology and metal catalysis are in the same order of magnitude. This is explained by the work-up procedures causing more environmental impact than the technology itself. Second, there are no a priori environmentally “unacceptable” catalytic methods. The environmental impact of a synthesis step depends rather on process parameters than on the technology employed. Finally, three parameters most important to an LCA of chemical reactions were identified: (1) the concentration of the reactants and, hence, the amount of solvent used, (2) all energy intensive steps such as distillations, and (3) the catalyst losses.