Synthesis and properties of Ti-MOR molecular sieve on the oxidation of cyclohexene: Influence of the Ti source

The incorporation of Ti in a molecular sieve having a MFI structure has generated a new material, TS-1. This new material is very active for the oxidation of organic compounds in the liquid phase, using H2O2 as oxidizing agent. However, TS-1 has medium diameter micropores, which adversely affects the diffusion of molecules with kinetic diameters larger than 5.5 Å. This limitation has provided a challenge for researchers to develop titanium-silicates with larger pore diameter. The purpose of this study is to compare physical–chemical and catalytic properties of Ti-MOR synthesized through Ti(OC2H5)4 (TEOT) and H2TiF6 as Ti sources. The results showed the formation of a MOR structure using the H2TiF6 as the Ti source. The incorporation of Ti to Ti-MOR structure synthesized using H2TiF6 is lower than for TEOT, however with a larger formation of pentacoordinated Ti in the framework. The Ti species incorporated to the catalyst synthesized using H2TiF6 are more active for the oxidation of cyclohexene than TEOT. However a sample synthesized with TEOT provides a higher selectivity for the formation of cyclohexene oxide.