Controlled detitanation of ETS-10 materials through the post-synthetic treatment and their applications to the liquid-phase epoxidation of alkenes

Treatments of ETS-10 titanosilicates with HCl, NH4Cl or citric acid led to the change in the coordination environment of Ti. These treatments also led to the partial extraction of Ti from the framework of ETS-10. The local structural changes brought about the formation of the active sites for the epoxidation of cyclohexene with H2O2. The highest epoxidation activity and efficiency of H2O2 as an oxidant were achieved when the original [Na, K]-type ETS-10 was treated with 3.7 mol dm(-3) NH4Cl solution followed by the calcination at 723 K. (C) 2004 Elsevier Inc. All rights reserved.