Oxidation of ethylene glycol: Unity of chemical and electrochemical catalysis

Abstract

The catalytic oxidation of ethylene glycol, both chemically (reaction with oxygen) and electrochemically (application of potential), have been studied in a batch reactor on three different catalysts. The products have been identified and their concentrations measured. For experiments on chemical oxidation, in addition to the analysis of the products, the variation of the potential developed on the catalyst with time was measured. The electrochemical experiments were designed such that the potential of the catalyst-coated electrode varies with time in a manner identical to variation of the potential with time observed for chemical experiments. The products and their respective concentrations obtained for both the chemical oxidation of ethylene glycol with molecular oxygen as well as the electrochemical oxidation were found to be in excellent agreement. The data presented here suggest that at molecular level, catalytic chemical oxidation on heterogeneous catalyst involves transfer of electrons from ethylene glycol to oxygen via two or more electrochemical reactions through the catalyst.