Preparation of S_2O_8~(2-)/ZrO_2-TiO_2 solid superacid catalyst and its catalytic activity for esterification

Solid superacid catalyst S2O82-/ZrO2-TiO2 was prepared by co-precipitation and low temperature aging method,and characterized by XRD,FT-IR and SEM.The effects of molar ratio of Zr to Ti in the catalyst,calcination temperature,the concentration of impregnating solution(NH4)2S2O8,and impregnating time,mole ratio of stearic acid to butanol and reaction temperature on catalytic activity of the catalyst were investigated using S2O82-/ZrO2-TiO2 solid superacid as the catalyst and the synthesis of butyl stearate as the probe reaction.The results showed that the esterification rate of 98.69% was attained under the optimum condition as follows:n(Zr)∶ n(Ti)=2∶ 2,the concentration of impregnating solution(NH4)2S2O8 0.5 mol·L-1,impregnating time 6 h,calcination temperature 500 ℃,n(stearic acid)∶n(butanol)=1∶ 3,catalyst dosage 0.2 g,reaction temperature 120 ℃ and reaction time 3 h.