Catalytic activity of carbon-based solid acids in the esterification synthesis of 1,4-butanediol disuccinate diisooctyl

Carbon-based solid acids were prepared by coking mixtures of p-toluene sulfonic acid and soluble starch with different ratios at different temperatures. The effects of the p-toluene sulfonic acid/soluble starch mass ratio, coking temperature and time on their catalytic activities in the esterification reaction of maleic anhydride with ethylene glycol were investigated. Results indicated that the activity of the acid was the highest when amixture with the mass ratio of 0.5 was coked at 200℃ for 8 h. The activity remained high after the solid acid had been used 5 times.