Scalable and efficient electrochemical bromination of arenes with Faradaic efficiencies surpassing 90%

Developing cost-effective and environmentally friendly approaches to synthesize brominated chemicals, which are important intermediates for the synthesis of various useful molecules such as pharmaceuticals, surfactants, pesticides, and biologically active heterocyclic compounds, is of great significance. Herein, we present a highly efficient electrochemical bromine evolution reaction over vacancy rich Co3O4 using cheap NaBr as the bromine source for the synthesis of valuable brominated fine chemicals and pharmaceuticals under ambient conditions. The introduction of oxygen vacancy onto Co3O4 can greatly enhance the activity and selectivity of bromine evolution reaction by optimizing Br* intermediate adsorption and desorption, enabling bromination of a series of bioactive molecules and pharmaceuticals at high yields. Traditional bromine chemistry uses Br2, which is environmentally unfriendly and wasteful. Here, the authors design a scalable electrochemical route to synthesize Br-substituted molecules using NaBr over Co3O4 under mild conditions and with high selectivity.