Epoxidation of allyl alcohol to glycidol using titanium silicalite TS-1: Effect of the reaction conditions and catalyst acidity

The epoxidation of allyl alcohol to glycidol using the titanium silicalite TS-1 with hydrogen peroxide as the oxidant is described and discussed in detail. The reaction conditions (alcohol, solvent, temperature) required to obtain 100% selectivity to glycidol are described and this selectivity has been observed at conversions of allyl alcohol of up to 20%. Addition of excess hydrogen peroxide enhances conversion but does not appear to affect selectivity to glycidol deleteriously, whereas addition of hydrogen peroxide over an extended time period is not particularly beneficial. The major side reactions are the oxidation of the alcohol solvent and the ring opening solvolysis of the glycidol that leads to the formation of alkoxy diols. Base treatment of the TS-1 using sodium azide enhances the glycidol selectivity, whereas the incorporation of Bronsted acid sites by addition of aluminium into the framework structure of TS-1 enhances the selectivity to the products of solvolysis ring opening reactions.