Synthesis of Styrene Oxide with Hydrogen Peroxide Catalyzed by Heteropoly Acids Under PTC

Styrene was epoxidized with commercially available hydrogen peroxide (15% H_2O_2) by using a combination of Mo- and W-based heteropoly acids with an appropriate ammonium salt such as tert-butylammonium chloride,under two-phase conditions using 1,2-dichloroethane as the solvent.By this method,styrene was epoxidized in high yields under mild conditions and after relatively short reaction times.It was found that the optimum reaction time was 3 h,the reaction temperature was 60 ℃, pH was (2.00),and the best catalyst for the epoxidation of styrene was composed of 9 mol molybdic acid and 1 mol tungstic acid.Under these conditions, the yield of styrene oxide is 81.2%.Meanwhile,the fresh catalyst has been characterized by IR and UV.