ZHAO Dishun, GE Jingjing, ZHAI Jianhua, et al. Synthesis of succinic acid diisopropyl ester catalyzed by Lewis acid ionic liquids[J]. CIESC Journal, 2014, (2): 561-569.
Nine kinds of different Lewis acid ionic liquids were synthesized by two-step process and their structures were characterized with 1H NMR and FT-IR. Lewis acid ionic liquids prepared were used to catalyze the esterification reaction of succinic acid and isopropyl alcohol. With the increase of dosage of halide
the ionic liquids showed stronger acidity. [Bmim]Br-Fe2Cl6 had the best catalytic performance
and optimal conditions for the synthesis of succinic acid diisopropyl ester were obtained as follows
amount of catalyst 10.0%(g/g)of succinic acid
reaction temperature 100℃ and reaction time 4 h
succinic acid and isopropyl alcohol ratio 1:5. Under the optimal conditions
the yield of succinic acid diisopropyl ester was up to 88.9%
esterification rate was 92.7%.The catalyst was recycled 6 times
and the yield of succinic acid diisopropyl ester only decreased by 1.7%.