Reactivity of the Gold/Water Interface During Selective Oxidation Catalysis

Indirect Oxidation by Oxygen Partial oxidation of alcohols to aldehydes and ketones must avoid complete oxidation to carbon dioxide and water. Zope et al. (p. 74 ) examined the partial oxidation of ethanol and glycerol to acids in alkaline aqueous solvents over gold and platinum catalysts. Conversions were highest for gold supported on titania, but studies with isotopically labeled molecular oxygen showed that oxygen incorporated into the acid comes from hydroxide ions. Direct incorporation of oxygen did not occur even for the platinum catalysts, despite the fact that oxygen can dissociate on this metal. Instead, molecular oxygen appeared to regenerate hydroxide ions at the metal surface through the formation of peroxide intermediates.