响应面分析法优化乙酸正辛酯制备工艺研究

Optimization of Process Variables in the Synthesis of Octyl Acetate by Response Surface Methodology

摘要: 采用响应面分析法优化酸性离子液体催化制备乙酸正辛酯的工艺条件。在单因素实验的基础上，选取反应时间、酸醇物质的量比、带水剂用量和催化剂用量4个因素进行Box–Behnken中心组合设计。实验结果表明，带水剂量与催化剂用量的相互作用和反应物物质的量比和离子液体剂量的相互作用最大；离子液体1-甲基-3-(丙基-3-磺酸基)咪唑硫酸氢盐([HSO3-pmim]HSO4)催化合成乙酸正辛酯的最佳反应条件为：反应时间1 h，n(乙酸):n (正辛醇) = 1:1.8，离子液体剂量5%，带水剂用量10 mL，在该条件下，乙酸正辛酯的酯化率为95.4%，与模型预测值基本相符。[HSO3-pmim]HSO4离子液体在催化乙酸正辛酯制备过程中具有良好的催化活性和稳定性。

Abstract: Response surface methodology (RSM) was applied to optimize the synthesis of octyl acetate from n-octanol catalyzed by acidic ionic liquid. Based on the single factor experiments, Box-Behnken central composite design was adopted to investigate the effects of various reaction conditions, including reaction time, alcohol/acid mole ratio, amount of water carrying agent, the amount of ionic liquid and their interactions on the esterification. The analysis from Design-Expert showed that the interactions between the amount of water carrying agent and the catalyst dosage, the molar ratio and the amount of ionic liquid were the strongest. The optimum conditions were as follows: reaction time 1 h, n(acetic acid):n(n-octanol) = 1:1.8, ionic liquid 5% of acid and the amount of water carrying agent 10 mL. Under the optimized conditions, the yield of octyl acetate reached 95.4%, in close agreement with values predicted by the mathe- matical model. [HSO3-pmim]HSO4 ionic liquid showed the good catalytic properties and stability on the esterification of n-octanol with acetic acid.