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为了减少离子液体用量,缩短反应时间,提高酯化反应的催化效率,该文以硅胶为原料与-γ(2,3-环氧丙氧基)丙基三甲氧基硅烷(KH-560)反应,合成了环氧基硅烷化硅胶,再与1-甲基咪唑硫酸氢盐发生开环反应,制备了一种硅胶固定化1-甲基咪唑硫酸氢盐离子液体。探讨了该离子液体在无机酸促进下对合成乙酸乙酯反应中原料摩尔比、酸的用量及离子液体用量等因素对反应的影响。实验表明,当n(乙醇)∶n(乙酸)=1.5∶1,该固定化离子液体用量为1.00 g,盐酸用量为2.0 mL时,乙酸乙酯的最高产率可达90.0%。固定化离子液体重复使用5次,酯的产率由90.0%降至85.1%。将该固定化离子液体应用于催化乙酸异戊酯、苯甲酸乙酯、草酸二乙酯、乙酸正丁酯和马来酸二乙酯的合成,酯的产率比仅用盐酸单组分催化分别提高了20.4%、25.6%、28.2%、22.3%和16.1%。通过简单滤除就可实现离子液体与产物的分离。
In order to reduce the amount of ionic liquid, shorten the reaction time and improve the catalytic efficiency of esterification reaction, the reaction of -γ (2,3-epoxypropoxy) propyltrimethoxysilane (KH-560) with silica gel as raw material , An epoxy silylated silica gel was synthesized and then ring-opened with 1-methylimidazolium hydrogen sulfate to prepare a silica-based immobilized 1-methylimidazolium hydrogen sulfate ionic liquid. The effects of molar ratio of raw materials, the amount of acid and the amount of ionic liquid on the reaction of the synthesis of ethyl acetate in the presence of inorganic acid were discussed. Experiments show that the highest yield of ethyl acetate is up to 90.0% when the molar ratio of n (ethanol): n (acetic acid) is 1.5:1, the amount of immobilized ionic liquid is 1.00 g and the amount of hydrochloric acid is 2.0 mL. The immobilized ionic liquid was reused 5 times and the ester yield was reduced from 90.0% to 85.1%. The immobilized ionic liquid was used to catalyze the synthesis of isoamyl acetate, ethyl benzoate, diethyl oxalate, n-butyl acetate and diethyl maleate. The yield of ester was more than that of monocomponent hydrochloride Increased by 20.4%, 25.6%, 28.2%, 22.3% and 16.1% respectively. The separation of the ionic liquid from the product can be achieved by simple filtration.