SYNTHESIS OF BENZYL PROPIONATE BY THE COMPOSITE SOLID SUPERACID CATALYST S_2O_8~(2-)-/TiO_2-MoO_3

The novel composite solid superacid catalyst S2O2-8-/TiO2-MoO3 was prepared by TiCl4as the raw material with precipitation-impregnation method,and it was used in the synthesis of benzyl propionate.The optimum conditions of catalyst preparation were: calcination temperature 500 ℃,impregnation concentration of ammonium peroxodisulfate 0.5 mol/L,impregnation concentration of(NH4)6Mo7O24 0.1 mol/L,calcination time 2.5 h.Based on the orthogonal experiment,the optimum synthetic conditions of benzyl propionate were resulted as follows: the molar ratio of benzyl alcohol to propionic acid was 1.5∶1.0,mass of the catalyst was 0.6 g(when propionic acid was 0.2 mol),the volume of the water removing reagent cyclohexane was 12 mL,and the reaction time was 2.5 h.The yield of esterification was more than 96% under above conditions.The novel type of catalyst S2O2-8-/TiO2-MoO3 has the features of highly activated,non-polluting and reusable.