关键词: SBA-15, 固定化, 离子液体, 酯化反应, 催化剂

Abstract:

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.

Key words: SBA-15, immobilization, ionic liquid, esterification, catalyst