Heteropoly Tungstate Supported on Metal Oxide Catalysts for Liquid Phase Oxidation of Benzyl Alcohol with Hydrogen Peroxide

A series of metal oxide supported tungstophosphoric acid catalysts were prepared by impregnation.The physicochemical and acidic properties of these materials were characterized by a variety of different analytical and spectroscopic techniques, namely Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) method, and nuclear magnetic resonance (NMR), and exploited as heterogeneous catalysts for selective oxidation of benzyl alcohol (BzOH) with hydrogen peroxide (H 2 O 2 ).Among them, 20 wt.% H 3 PW 12 O 40 /CeO 2 catalyst exhibited the best oxidative activity.Further process optimization by response surface methodology (RSM) based on the Box-Behnken design model resulted in a benzyl alcohol conversion of 95.2% and a benzaldehyde yield of 94.2% with 98.9% selectivity, in good agreement with the experimental results.Kinetic studies based on an irreversible parallel reaction model led to an activation energy (E a ) of 44.73 kJ mol -1 .