【摘要】 首先在间歇反应条件下考察了基于吡咯烷酮/咪唑阳离子的5种硫酸氢盐离子液体作为催化剂用于乙酸和乙醇酯化反应的催化活性,并与浓硫酸进行了比较。然后选取成本最低和催化效果较佳的离子液体——2-吡咯烷酮硫酸氢盐离子液体([Hnhp]HSO4),采用反应精馏技术,进行了连续酯化制备乙酸乙酯的研究。结果表明,当釜液酸醇比为6∶1(均为摩尔比),[Hnhp]HSO4用量为乙酸物质的量的0.5%,釜温110℃,原料进料速度为40 m L/h,进料醇酸比为1.02∶1,回流比为1,回流酯流速为35 m L/h,反应48 h,塔顶粗酯的酯含量达94%~96%,过程可保持较好的连续性和稳定性。相比于传统的浓硫酸催化剂,离子液体[Hnhp]HSO4对设备腐蚀性小,对环境友好。更多还原

【Abstract】 The catalytic activities of a series of Brnsted acidic ionic liquids in the esterification of acetic acid with ethanol were investigated and compared with those of the catalyst H2SO4 under batch conditions. Among the five hydrogen sulfate ionic liquids with cations of pyrrolidonium and imidazolium,the pyrrolidonium ionic liquid [Hnhp]HSO4exhibited the best performance and was of the lowest cost. The distillation technology,combined with the ionic liquid [Hnhp]HSO4as a catalyst,was applied in continuous preparation of ethyl acetate. Under the optimum conditions of n( HOAc) ∶ n( Et OH) ∶n( [Hnhp]HSO4) = 6∶1∶0. 03( in reaction vessel),110 ℃,n( Et OH) ∶n( HOAc) = 1. 02∶1( feedstock),feeding rate 40 m L/h,reflux ratio 1,and ester reflux 35 m L/h,the Et OAc content in the coarse ester product taken from the top of tower reached 94% ~ 96%. The reactive distillation system maintained a good balance even after 48 h of reaction. Compared with sulfuric acid,the ionic liquid[Hnhp]HSO4as a catalyst for the esterification is reusable,less corrosive to equipment and friendly to environment.更多还原