Titanium Silicalite-1 Catalyst Research Articles

Synthesis of propylene oxide from propylene and hydrogen peroxide catalyzed by titanium silicalite

The epoxidation of propylene with hydrogen peroxide in the liquid phase, in the presence of titanium silicalite catalyst (TS-1), is described. The best solvents are methanol and methanol/ water mixtures. The temperature is normally between room temperature and 60°C. Under these conditions, reaction rates are fast, yields on H 2O 2 are quantitative, and selectivity to propylene oxide is very high. Propylene glycol and its monomethyl ethers and trace amounts of formaldehyde are the only by-products formed. Selectivity is further improved and the hydrolysis of the epoxide is almost suppressed when the residual acidity of the catalyst is completely neutralized. The activity of spent catalyst is recovered by calcining at 550°C or, more simply, by washing with solvents. Complete activity recovery shows that Ti is not removed from the crystalline framework during the epoxidation reactions.

A test reaction for titanium silicalite catalysts

The catalytic hydroxylation of phenol to hydroquinone and catechol can be used for checking the quality of titanium silicate catalysts since the selectivity of these catalysts is strongly affected by the presence of small amounts of non-framework titania. Titanium silicates prepared by modification of [Al]ZSM-5 exhibits the same catalytic properties as hydrothermally synthesized TS-1 of high purity.