Catalytic performance of Ti-SBA-15 prepared by chemical vapor deposition for propylene epoxidation

Ti-SBA-15C catalysts were prepared by supporting Ti on SBA-15 with chemical vapor deposition (CVD) using TiCl₄ as titanium source, and were characterized by XRD, N₂ adsorption, FT-IR and ICP. The results show that SBA-15E prepared by ethanol solution extracting template has higher concentration of surface Si-OH groups than SBA-15 calcined at 550 °C, resulting in high Ti content on Ti-SBA-15EC prepared by CVD. The temperature and time of TiCl₄ deposition affect the Ti content and catalytic activity of Ti-SBA-15EC for the epoxidation of propylene with cumene hydroperoxide (CHP). Ti-SBA-15EC prepared by CVD at 700 °C for 1.5 h exhibits more excellent performance than Ti-SBA-15C, Ti-SBA-15 prepared hydrothermally and Ti/SBA-15 (impregnation method), and the 87.3% conversion of CHP and 96.4% selectivity to propylene oxide can be obtained at 80 °C for 4 h. The performance of Ti-SBA-15EC is decreased hardly for the epoxidation of propylene after used repeatedly 6 times.