An effective heterogeneous WO3/TiO2-SiO2 catalyst for selective oxidation of cyclopentene to glutaraldehyde by H2O2

TiO2-SiO2 mixed oxide with large pore size was synthesized by the xerogel m ethod and it was then used to prepare the WO3/TiO2-SiO2 catalyst by an inci pient wetness method. The as-prepared WO3/TiO2-SiO2 sample was employed as the first heterogeneous catalyst in the liquid-phase cyclopentene oxidation by aqueous H2O2, which exhibited higher selectivity (about 75%) to glutara ldehyde (GA) and, in turn, higher GA yield than the WO3/SiO2 heterogeneous catalyst and even the tungstic acid homogeneous catalyst under the same rea ction conditions. The amorphous WO3 phase was identified as the active site s and the loss of the active sites was proved to be not important. The life time of the catalyst was determined and its regeneration method was propose d. The effects of various factors on the catalytic behaviors, such as the W O3 loading, the calcination temperature, the surface acidity and the reacti on media, were investigated and discussed based on various characterization s including BET, XRD, XPS, FTIR, EXAFS and Raman spectra etc.