In situ electrochemical regeneration of permanganate ion for sustainable oxidation reactions

Abstract

Numerous stoichiometric oxidants have been employed for the oxidative production of high-end fine chemicals. However, regeneration of these oxidants often suffers from high energy consumption and complex separation. Here, we report an in situ electrochemical approach for the regeneration of a widely used oxidant, permanganate (MnO₄⁻), by coupling electrochemical and chemical reactions in an integrated system. Using electrosynthesis of 1,3,2-dioxathiolane 2,2-dioxide (DTD), a commercial electrolyte additive in Li-ion batteries, as a representative example, the electrochemically generated MnO₄⁻ shows remarkable performance as a redox mediator for catalyzing ethylene sulfite oxidation to produce DTD. By employing pulsed voltammetry, electrosynthesis of DTD can be performed in a single-pass continuous flow electrolyzer with 85% yield and 72% Faradaic efficiency. The practicality of the developed method is demonstrated with a wide substrate scope, robust anode stability, and scaling capability to achieve a DTD production capacity of 500 g/h in a 1-m² electrolyzer.