Studies On Selective Oxidation Of Alcohols With Hydrogen Peroxide

Selective oxidation of alcohols to aldehydes or ketones is an important organic transformation.Traditionally,the oxidation of alcohols generally requires stoichiometric amounts of inorganic oxidants such as chromium(VI)and manganese(VII)reagents.Hydrogen peroxide as a clean oxidant has attracted wide attention owing to its merits including mild and atom efficient.In order to improve the activity of selective oxidation of alcohol with hydrogen peroxide,exploring a facile and efficient catalytic system has important significance.Molybdenum trioxide was found to be an effective catalyst for selective oxidation of alcohols to the corresponding carbonyl compounds with hydrogen peroxide without solvent.The selectivity of cyclohexanone was 100%under this oxidation reaction.In addition to fatty alcohols,different aromatic alcohols could also be oxidized to aldehydes or ketones with high selectivity.The possible mechanism was found that molybdenum trioxide was oxidized by hydrogen peroxide to obtain a diperoxo active substance and then the corresponding alcohol was oxidized by the diperoxo active substance.Ammonium tungstate catalyst was found to be facile and efficient for selective oxidation of alcohols to aldehydes or ketones with hydrogen peroxide.Graphene oxide was obtained by modified Hummers method and characterized by SEM,FTIR,X-ray powder diffraction and differential scanning calorimetry.Graphene oxide could be readily separated from the mixtures by centrifugation.Graphene oxide could be recycled in the reaction.This method was found to be suitable for a range of fatty alcohols and aromatic alcohols.The yield of cyclohexanone was 93%and the yield of benzophenone was 98%.A plausible catalytic mechanism was proposed that a diperoxo active specie was generated from the action of ammonium tungstate and hydrogen peroxide.The diperoxo active specie was as active oxidant for alcohols in the reaction.