Bromine-mediated electrochemical refinery towards tartaric acid

Abstract

Tartaric acid is an important ingredient widely used in the food, pharmaceutical, and cosmetic sectors. Over recent years, its rising industrial significance and market demand have called for more efficient and sustainable production strategies than those traditionally available. Herein, we propose bromine-mediated conversion from maleic acid—a common biomass derivative to tartaric acid. To this end, hierarchical Mo₂C nanostructures are prepared as an efficient electrocatalyst for the bromine evolution reaction at close to the theoretical potential. Bromine generated at the anode then undergoes disproportionation to HOBr, and mediates the transformation of maleic acid to epoxysuccinic acid with high selectivity, which finally hydrolyzes to tartaric acid. Our demonstrated new approach circumvents the issue of product overoxidation usually encountered with direct electrochemical oxidation, and is thereby more energy efficient and atom economic.