Core-shell TiO2@SiO2 catalyst for transesterification of dimethyl carbonate and phenol to diphenyl carbonate

Abstract

Core-shell TiO2@SiO2 was prepared using a combination of reverse microemulsion and precipitation methods and used as a heterogeneous catalyst for the transesterification of dimethyl carbonate and phenol. TiO2@SiO2 calcined at 200 °C gave the best catalytic performance. When the amount of catalyst was 0.20 g, the phenol conversion and transesterification selectivity were 41.8% and 100%, respectively. Transmission electron microscopy was used to characterize the core-shell TiO2@SiO2 structure, and the results showed that TiO2@SiO2 is bilayer with a TiO2 core of diameter 220–300 nm and SiO2 shell of thickness 40–60 nm. The TiO2@SiO2 was reusable, and phenol conversion remained above 40% when the TiO2@SiO2 was used four times. The catalytic performance of TiO2@SiO2 in the transesterification of dimethyl carbonate and phenol was promoted by the formation of Ti–O–Si bonds.