Ti-Beta zeotypes with open Ti(OSi)3OH sites for the efficient epoxidation of cyclohexene with H2O2

Ti-Beta zeotypes, possessing three-dimensional 12-membered ring pore-opening channels, have shown some superior catalytic performance in the epoxidation of bulky cycloalkenes with hydrogen peroxide (H 2 O 2 ) in comparison with other titanosilicate zeotypes. However, some further improvement on the catalytic activity and selectivity of Ti-Beta zeotypes is still demanded for the industrialization of cycloalkenes epoxidation. In the present work, the catalytic performance of Ti-Beta in cyclohexene epoxidation was significantly improved via the transformation of their closed Ti(OSi) 4 sites into the open Ti(OSi) 3 OH ones by a simple NH 4 F treatment. Based on the extensive characterization results, it is found that the NH 4 F-treated Ti-Beta zeotypes with open Ti(OSi) 3 OH sites, named OH-Ti-Beta, possess a stronger Lewis acidity that is favorable to the production of cyclohexene oxide (CHO) from the epoxidation of cyclohexene with H 2 O 2 , compared to the parent Ti-Beta with closed Ti(OSi) 4 sites. Moreover, OH-Ti-Beta catalysts are reusable after the calcination of the deactivated zeotypes. Hence, it is expected that the current developed NH 4 F treatment can obtain efficient OH-Ti-Beta catalysts industrially applied in cyclohexene epoxidation.