Catalytic Performances of Silicon Dioxide Supported Titania as Catalyst in Transesterification between Diethyl Oxalate and Phenol

A series of silicon dioxide supported titania by the impregnation method for transesterification of diethyl oxalate (DEO) and phenol was carried out under the facile catalytic condition in the liquid phase at 453 k in the atmospheric pressure. Within different TiO2 loadings ranging from 1% to 20%, 10% TiO2/SiO2 performed best, giving 49.5% conversion of DEO and the total 100% selectivity to ethyl phenyl oxalate (EPO) and diethyl oxalate (DPO). To further study the relationship between catalytic performances and the catalysts structure, several characterization methods, analysis of X-ray diffraction (XRD), Raman spectroscopy measurement and FTIR of adsorbed pyridine studies were utilized. The results of XRD and Raman, showed amorphous structure of TiO2 on SiO2 below the 10% loading and crystalline form of TiO2 phase on SiO2 above the 10% loading. In addition, FTFR of adsorbed pyridine studies illuminated the Lewis-type acid sites were responsible for transesterification between DEO and phenol.