Catalytic aerobic epoxidation of bio-renewable alkenes using organic carbonates as green solvents

Abstract

Epoxides are important products in industry and organic synthesis. However, for large-scale applications, the methodologies are outdated due to the use of toxic reactants/solvents under non-safe conditions. In this work, we present a safer process for the epoxidation of alkenes which is aligned with green chemistry principles. A series of bio-renewable substrates was selectively epoxidized under mild conditions using environmentally friendly molecular oxygen as a final oxidant, isobutyraldehyde as a sacrificial reagent and a robust solid material based on a non-noble metal (cobalt) as a heterogeneous catalyst. Several organic carbonates, which are considered as sustainable solvents in modern ranks and are very scarcely exploited in epoxidation, have been studied as a reaction medium for this reaction. Dimethyl carbonate was proved to be an excellent green alternative to replace undesirable industrial solvents allowing to combine both high catalyst performance and high process sustainability.