Keggin-type heteropoly acids revealed high catalytic activity for swift and selective oxidation of various hydroxy functionalities to the corresponding carbonyl groups using ferric nitrate as an oxidant under mild and solvent-free conditions. We have found that the catalytic activities of the heteropoly acids were much higher than mineral or solid acids such as sulfuric acid, p-toluenesulfonic acid, triflic acid, acidic Amberlyst-15, Montmorillonite-K10 clay, and HY-zeolite.
