Esterification of oleic acid and methanol catalyzed by solid acid alumina sulfuric acid and its kinetics

Alumina sulfuric acid(ASA) solid acid catalyst was synthesized by alumina and chlorosulfonic acid with chloroform as solvent.Using conversion rate of oleic acid as index,the effects of loading amount of chlorosulfonic acid,reaction time,molar ratio of methanol to oleic acid and catalyst dosage on the esterification of oleic acid and methanol with ASA as catalyst were discussed.The results showed that the optimal esterification conditions were obtained as follows:loading amount of chlorosulfonic acid 4.1mmol/g,catalyst dosage 5%(based on the mass of oleic acid),reaction time 6 h,reaction temperature68 ℃ and molar ratio of methanol to oleic acid 8∶ 1.Under these conditions,the conversion rate of oleic acid reached 93.1%,and it was still over 80% when ASA was reused for five times.The esterification was accord to pseudo-second kinetic model at 303-333 K,the apparent activation energy was 54.34 kJ/mol,and the pre-exponential factor was 2.91 × 109 L/(mol·h).