Synthesis of di-iso-octyl phthalate and di-n-octyl phthalate

Di-iso-octyl phthalate and di-n-octyl phthalate was synthesized by using p-toluene sulphonic acid as catalyst.The influence of raw material ratio,catalyst consumption,reaction time,choice of water removal agent on the esterification yield were investigated and optimum processing conditions were determined.The result of investigation indicates that,when the mole ratio of phthalic anhydride and 2-ethyl hexanol and p-toluene sulphonic acid is 1∶3∶0.125,water carrying reagent 10 ml,the reaction time-1.5 h,the yield rate of esterification amounts to 97.43%.When the mole ratio of phthalic anhydride and n-octanol and p-toluene sulphonic acid is 1∶2.5∶0.142,water carrying reagent 10 ml,reaction time-1.5 h,the yield rate amounts to 98.46%.