Alkene Epoxidation and Oxygen Evolution Reactions Compete for Reactive Surface Oxygen Atoms on Gold Anodes.

Rates and selectivities for the partial oxidation of organic molecules on reactive electrodes depend on the identity and prevalence of reactive and spectator species. Here, we investigate the mechanism for the epoxidation of 1-hexene (CH) with reactive oxygen species formed by electrochemical oxidation of water (HO) on gold (Au) in an aqueous acetonitrile (CHCN) electrolyte. Cyclic voltammetry measurements demonstrate that oxygen (O) evolution competes with CH epoxidation, and the Au surface must oxidize before either reaction occurs.