Catalytic performance of surface-silylated and phenyl-bridged Ti-containing mesoporous silica for epoxidation of propylene

Abstract Titanium-doped phenyl-bridged ordered mesoporous organosilicon (Ti-PMO) was initially prepared by a one-step hydrothermal synthesis method under acidic conditions. Following silanization modification, a Ti-PMO-S sample was obtained with an improved surface hydrophobic characteristic. The environment of titanium within the samples was analyzed by Fourier-transform infrared spectroscopy (FT-IR), diffuse reflectance ultraviolet-visible spectroscopy (UV-Vis-DR), ammonia temperature programmed desorption (NH 3 -TPD), and Raman spectroscopy. Furthermore, the textural and structural properties of corresponding materials were characterized by X-ray diffraction (XRD), nitrogen adsorption-desorption isotherms and transmission electron microscopy (TEM). The results showed that Ti-PMO-S has more active Ti centers than Ti-SBA-15 and Ti-PMO on the basis of maintaining the mesoporous structure of ordered channels, despite the presence of few TiO 2 species. The catalytic performance of the synthesized samples was assessed in the epoxidation of propylene with tert-butyl hydroperoxide (TBHP) as an oxidant. The prepared Ti-PMO-S materials showed the best epoxidation performance under optimized conditions, with conversion of TBHP up to 95.8% and selectivity of propylene epoxide and tert butyl alcohol reaching 78.8% and 95.9%, respectively.