Epoxidation over niobium and titanium grafted MCM-41 and MCM-48 mesoporous molecular sieves.

Abstract

Highly dispersed niobium or titanium containing molecular sieve catalysts were prepared by post synthesis modification of anchoring at surface silanol groups, using direct grafting of niobium and titanium compounds onto the totally accessible inner and outer surface of siliceous MCM-41 and MCM-48 mesoporous molecular sieves. Different niobium and titanium compounds are used to accomplish the grafting. Catalytic epoxidation activity of niobium or titanium grafted mesoporous molecular sieves were studied using H2O2 as an oxidant. These niobium and titanium containing mesoporous molecular sieves exhibit higher epoxidation activity and better H2O2 selectivity.