Electrolytic Olefin Epoxidation for Sustainable Synthesis of Epoxy Compounds

Abstract

Electrolytic olefin epoxidation is regarded as a sustainable method for epoxy compounds synthesis with only oxygen or water as the oxygen atom source under mild conditions. After decades of slow development, this field is currently experiencing a renaissance and brought back to the spotlight with the emergence of novel electrode materials. Nowadays, various strategies have been developed for electrolytic olefin epoxidation, including olefin epoxidation initiated by O2 reduction at the cathode, direct/indirect olefin epoxidation promoted by water oxidation/redox mediators at the anode. Concurrently, a plethora of efficient and robust electrode materials such as PtPdOx, IrO2/TiO2, PdO and so on have been developed for olefin epoxidation via the direct oxygen atom transfer (OAT) mechanism or halide-mediated halohydrin formation and cyclization. As a result, the overoxidation of olefins to CO2 can be inhibited and high atom economy can be achieved. This review aims to provide an overview of the state of art on electrolytic olefin epoxidation and reflect the green advances in electrochemical epoxidation of olefins such as atom economy pathway with only oxygen or water as oxygen donor under mild conditions, avoiding overoxidation of olefins to CO2 in conventional processes and reducing the use of heavy metal reagents. Moreover, the perspectives are also presented to spur the further development in this field.