Preparation and property of supported titania catalysts for transesterification of dimethyl oxalate with phenol

The transesterification of dimethyl oxalate (DMO) with phenol over TiO2/SiO2 catalysts was conducted to produce methyl phenyl oxalate (MPO) and diphenyl oxalate (DPO). The TiO2/SiO2 catalysts prepared by wet impregnation of anhydrous ethanol solutions of tetrabutyl titanate showed high activity and excellent selectivity for the transesterification and good separability for reclaim. Various factors affecting the transesterification of DMO with phenol, such as calcination temperature, particle size of support, catalyst amount, TiO2 loading amount, and reaction time, were investigated. The study showed that the optimum calcination temperature for TiO2/SiO2 was 550°C. 53.1% conversion of DMO, 72.1% and 27.3% selectivity to MPO and DPO respectively, were obtained after 2-hour reaction at 180°C with 13% TiO2 loading and in the presence of TiO2/SiO2 calcinated at the above optimum temperature.