A reusable and active lacunary derivative [PW11O39]7− as benzyl alcohol oxidation catalyst with hydrogen peroxide

With 35% aqueous hydrogen peroxide (H2O2) as oxidant, benzyl alcohol (BzOH) was efficiently oxidized to benzaldehyde (BzH) over reaction-controlled phase-transfer catalyst [C7H7N(CH3)3]7PW11O39. Under the optimal conditions, 95.8% conversion of BzOH and over 99% selectivity of BzH, respectively, were obtained within 0.5 h. In this system, when the H2O2 was consumed up, the catalyst could be easily recovered from the reaction system by centrifugation as deposit. The catalyst could be recycled three times without obviously decreasing the catalytic activity and the recovery ratio of catalyst. Its FT-IR and 31P NMR spectroscopy indicated that the structure of catalyst was maintained well after the reaction.