Alumina and silica oxides as catalysts for the oxidation of benzoins to benzils under solvent-free conditions

Alumina or silica gel are used as catalysts for a solvent-free oxidation of benzoins to the corresponding benzils. These catalysts are easily recovered after completion of the reactions, which are carried out either by heating in a sand bath or using microwave irradiation. Comparison of the results obtained with both catalysts indicates that all the reactants examined were oxidized faster on alumina than on silica under these conditions.