Synthesis of di-n-butyl phthalate with SO_4~(2-)/ZrO_2-La_2O_3 solid superacid as catalyst

SO2-4/ZrO2-La2O3 solid superacid catalyst was prepared by coprecipitation in ammonia with ZrOCl2·8H2O and La(NO3)3·9H2O.Preparing conditions of the catalyst were molar ratio of ZrOCl2·8H2O to La(NO3)3·9H2O 6 ∶1,-15 ℃ ageing time 24 h,drying at 120 ℃ for 12 h,concentration of sulfuric acid 0.5 mol/L,impregnation time 4 h,drying at 120 ℃ for 1 h,calcination at 600 ℃ for 4 h.As concerning synthesis of di-n-butyl phthalate,effects of catalyst dosage,molar ratio of n-butyl alcohol to phthalic anhydride,reaction time,reaction temperature on esterification yield were studied.Under the optimal conditions of mole ratio of n-butyl alcohol to phthalic anhydride 3.5 ∶1,mass of catalyst for 2.7% of phthalic anhydride,reaction time 3 h and reaction temperature 160 ℃,esterification yield is 91.6%.