Synthesis of Ti-containing extra-large-pore zeolites of Ti-CIT-5 and Ti-SSZ-53 and their catalytic applications

摘要

Introduction of titanium into the frameworks of 14-ring extra-large-pore zeolites with CIT-5 (CFI-type, 7.2 x 7.5 angstrom) and SSZ-53 (SFH-type, 6.4 x 8.7 angstrom) topology has successfully been conducted by a chemical vapor deposition (CVD) method. The prepared titanosilicate zeolites have been characterized by XRD, SEM, UV-vis spectroscopy, IR spectroscopy, N-2 adsorption, and elemental analysis. According to the characterization data, titanium is mostly incorporated into the framework of the zeolite in a tetrahedrally coordinated state. The catalytic epoxidation of cycloalkenes with H2O2 and tert-butyl hydroperoxide (TBHP) has been measured. The prepared titanosilicates with extra-large pores show superior performances for bulky molecule oxidation using TBHP as an oxidant compared to medium-pore TS-1 and large-pore Ti-beta.