Solvent-free oxidation of alcohols catalyzed by an efficient and reusable heteropolyphosphatotungstate

With aqueous hydrogen peroxide as oxidant, secondary alcohols could be efficiently oxidized to ketones in the presence of hexadecyl trimethyl ammonium heteropolyphosphatotungstate ((n-C16H33N(CH3)3)3[PW4O16]) under solvent-free conditions. The oxidation of alcohol over 0.5 mol% (based on molar amount of hydrogen peroxide) catalyst occurred at 90 °C to give the corresponding ketones with above 92% yield and 97% selectivity. The catalyst could be reused without loss of selectivity.