Mechanism for the Electrocatalyzed Oxidation of Glycerol Deduced from an Analysis of Chemical Instabilities

Abstract

The electrocatalyzed oxidation of glycerol in alkaline solution is compared with the oxidations of ethylene glycol and methanol. An analysis of behaviors caused by instabilities provides strong evidence that the elementary reactions that dominate the oxidation of glycerol are the same as those that dominate the oxidation of methanol. These reactions include the formation of surface bonded CO and its reaction with surface bonded hydroxyl radicals. The reactions that precede the dominant reactions in the oxidation of glycerol are relatively fast and must involve cleavage of C−C bonds. Evidence from phase diagrams indicates that the most probable sequence for the fast reactions requires a sufficient number of neighboring vacant sites to produce three surface-bonded CO complexes for each glycerol molecule. Reaction sequences that lead to zero, one, or two CO complexes occur with small probability.