Preparation of Titanium Modified TUD-1 Catalysts for Propylene Epoxidation

A three-dimensional sponge-like mesoporous, Ti-TUD-1 catalyst was synthesized by a direct hydrothermal treatment method. Its synthesis was modified to introduce more tetrahedral-coordinated Ti species into the framework of TUD-1 matrix, by controlling the hydrolysis of titanium and silicon sources. The TUD-1 catalyst was characterized by XRD, FT-IR, ICP-AES, UV-Raman, UV-vis DRS, BJH/BET and Si-29 MAS NMR analyses, indicating that addition orders of substrate played a crucial role during the Ti-TUD-1 catalyst preparation, indicating the amount of tetrahedral-coordinated Ti species was closely related to the addition order of substrate. The presence of Ti species affected the internal structure and connectivity of TUD-1 matrix. The Ti-TUD-1 catalyst exhibited high catalytic activity, especially good PO selectivity, due to the tetrahedral-coordinated Ti species into the framework of TUD-1 matrix. Furthermore, the effect of the TBOT/TEOS and TEA/TEOS molar ratios, on the catalytic activity was also studied, demonstrating that adequate molar ratios promoted an improvement the catalytic activity. Textural properties of Ti-TUD-1 were related to the addition order of substrate. Ti-TUD-1 catalyst was synthesized by controlling the hydrolysis of titanium and silicon sources. Amount of tetrahedral-coordinated Ti species also depend on the addition order of substrate.