Titanium silicate molecular sieves catalytic properties

The main objective of this review is to summarize and critically analyze recent advances made in the characterization and catalytic properties of titanium silicate molecular sieves after the reviews of Notari (33) and Vayssilov (34) in 1996 and 1997, respectively. Of special interest are... 

Several preparation methods have been reported for the synthesis of TS-1. In this work, we have investigated the physicochemical properties of TS-1 samples synthesized by different preparation metiiods and tested these materials as catalysts for the oxidation of n-octane, 1-hexene and phenol using aqueous hydrogen peroxide (30 wt%) as oxidant at temperatures below 100 C. For comparison, Ti02 (anatase) and the octahedral titanium-containing silicate molecular sieve (ETS-10) (5) have been studied. The effect of the presence of aluminum and/or sodium on the catalytic activity of TS-1 is also discussed. 

In the present work the synthesis of highly dispersed niobium or titanium containing mesoporous molecular sieves catalyst by direct grafting of different niobium and titanium compounds is reported. Grafting is achieved by anchoring the desired compounds on the surface hydroxyl groups located on the inner and outer surface of siliceous MCM-41 and MCM-48 mesoporous molecular sieves. Catalytic activity was evaluated in the liquid phase epoxidation of a-pinene with hydrogen peroxide as oxidant and the results are compared with widely studied titanium silicalites. The emphasis is directed mainly on catalytic applications of niobium or titanium anchored material to add a more detailed view on their structural physicochemical properties. 

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