硫酸氢根吡啶催化制备乙酸正丁酯的酯化反应精馏过程模拟

Computer simulation of the n-butyl acetate esterification process in a reactive distillation column with an ionic liquid as the catalyst

采用离子液体硫酸氢根吡啶([Hpy][HSO4])作为催化剂,对乙酸和正丁醇在反应精馏塔中进行酯化反应生成乙酸正丁酯的过程进行模拟研究。在缺乏实验数据的情况下,使用真实溶剂似导体屏蔽模型(COSMO-RS)方法预测了离子液体与其他物质的汽液相平衡,得到了离子液体与反应体系的二元交互参数。基于共沸精馏概念设计了带有分相器的反应精馏塔,实现了离子液体的循环利用。分析了反应精馏塔总塔板数、进料模式、进料塔板位置、再沸器热值和塔板持液量对于产品质量和乙酸转化率的影响,结果表明,当反应精馏塔塔板总数为28,反应物从第4块塔板同时进料,离子液体从第2块塔板进料,且塔板持液量为0.05 m3时,乙酸正丁酯纯度和乙酸转化率均可达99.9%。

The esterification reaction of acetic acid and n-butanol to produce n-butyl acetate has been simulated in a reactive distillation column by using the ionic liquid pyridinium hydrogen sulfate( [Hpy][HSO4]) as the catalyst. Due to the absence of experimental vapor-liquid equilibrium( VLE) data for mixtures of ionic liquids and other substances,the conductor-like screening model for real solvents( COSMO-RS) method was used to predict the phase equilibrium and to obtain the binary interaction parameters. Based on the concepts of azeotropic distillation,a phase splitter was used and recycling of the ionic liquid was achieved. The effects of varying the total number of trays,the feed mode,the position of the feed tray,the heat duty of the reboiler,and the liquid holdup on the product quality and acetic acid conversion rate was analyzed. Our results showed that for a total number of trays of 28,liquid holdup of 0. 05 m3,reactant feed location of the 4th tray and ionic liquid feed location of the 2nd tray,the purity of n-butyl acetate can reach 99. 9% and the acetic acid conversion rate is 99. 9%.