Ti incorporation in MCM-41 mesoporous molecular sieves using hydrothermal synthesis

Abstract Titanium-containing mesoporous materials （Ti-MCM-41） were obtained by hydrothennal synthesis. Such materials are active catalysts for the transesterifica- tion of dimethyl oxalate and phenol to produce diphenyl oxalate. To understand the role of the Ti in the catalytic process, Ti-MCM-41 samples with different Si/Ti ratios （from 5 to 100） were prepared and the samples were analyzed by Fourier transform infrared spectroscopy, UV- visible spectroscopy, and ammonia temperature pro- grammed desorption. It was concluded that the Ti is incorporated into the framework of the MCM-41 and formed weak Lewis acid sites. In addition, the number of Ti（IV） sites increased as the amount of titanium increased. X-ray powder diffraction, N2 adsorpfion-desorption and transmission electron microscopy results showed that the Ti-MCM-41 samples have a hexagonal arrangement of mono-dimensional pores. A large number of Ti（IV） sites coupled with the mesoporous structure and large pore diameters are favorable for the transesterification catalytic properties of Ti-MCM-41.