EPOXIDATION OF STYRENE OVER A TITANIUM SILICATE MOLECULAR-SIEVE TS-1 USING DILUTE H2O2 AS OXIDIZING-AGENT

The epoxidation of styrene was studied using a titanium silicate molec ular sieve TS-1 as catalyst and dilute (25%) H2O2 as oxidizing agent. Mainly two types of reactions were observed: The major reaction (simil ar to 75-85 mole%) was epoxidation and its further isomerization into phenylacetaldehyde. The other reaction was oxidative cleavage into ben zaldehyde (similar to 10-20 mole%). While generally the products were analyzed by capillary GC and GCMS, in certain cases, the products were separated and isolated by column chromatography and analyzed by H-1 a nd C-13 NMR spectroscopy. Polar and nonpolar solvents have marked infl uence on product distribution in styrene epoxidation. In methanol, a s ignificant part of styrene epoxide undergoes alcoholysis through the a ddition of methanol forming 2-methoxy-2-phenyl-ethanol. The influence of reaction time, temperature, and styrene/H2O2 molar ratio on the con version and product distribution was also studied. (C) 1995 Academic P ress, Inc.