Catalytic synthesis of dibutyl phthalate catalyzed by copper p-toluene sulfonate

Copper p-toluene sulfonate was used as the catalyst for esterification of phthalic anhydride with n-butanol.The influence of alcohol-to-acid molar ratio,catalyst dosage and reaction time was investigated.The results showed that appropriate reaction condition was as follows:n-butanol-to-phthalic-anhydride molar ratio 2.0∶1,catalyst dosage=1.5% molar percentage of phthalic anhydride,reaction time 2.5 h at reflux temperature.Esterification rate of up to 98.5 % was obtained.Copper p-toluene sulfonate could be repeated used after simple phase-separation without need of regeneration.The catalyst had the merits of both homogeneous and heterogeneous catalyst.