To decrease the usage of ionic liquid and facilitate the separation of catalyst from the product

a novel Brønsted acidic ionic liquid catalyst of 1-(3-sulfopropyl)caprolactam hydrogen sulfate ([C3SO3HCP]HSO4) supported on SBA-15 was prepared through covalent bond grafting method. In order to achieve structural information and stability of catalysts

the samples were characterized by FT-IR

TG

XRD

BET and TEM techniques. The catalytic activities of the immobilized ionic liquid for the esterification of succinic anhydride with ethanol were investigated. It showed that [C3SO3HCP]HSO4 has been successfully immobilized onto the SBA-15 with relatively good thermal stability and catalytic activity

which overcomes the drawbacks of low activity of heterogeneous catalyst

and difficult separation of homogeneous catalyst from the reaction system. Under the optimized conditions of 5%(mass) of catalyst dosage

n(C4H4O3):n(C2H5OH)=1:3

80℃ of reaction temperature

4 h of reaction time

and 30%(mass) of water carrying agent dosage

the yield of diethyl succinate was up to 93.7%. The SBA-15 immobilized ionic liquids remained satisfactory catalytic activity for the synthesis of diethyl succinate after 8 cycles. Moreover

the IL/SBA-15 exhibited relatively high yield of diethyl succinate for a series of esterification and the product could be separated easily from the reaction system.