反应精馏法合成苯甲酸异丁酯的工艺研究

Study on synthesis of isobutyl benzoate by reactive distillation

用反应精馏法合成了苯甲酸异丁酯,研究了原料配比、反应精馏时间、回流比、催化剂用量及带水剂对酯化率的影响.结果表明,反应精馏法合成苯甲酸异丁酯,可以突破酯化过程中化学平衡的限制,提高酯化率;能综合利用反应热,克服共沸物实现产品的高精度分离提纯.最佳条件:苯甲酸30 g,异丁醇与苯甲酸的物质的量之比为5,回流比为3,催化剂用量为苯甲酸质量的8.33%,环己烷带水剂60 mL,反应精馏时间为2 h.最佳工艺条件下苯甲酸的酯化率可达82.7%,苯甲酸异丁酯的收率为75.9%.

Isobutyl benzoate was synthesized by reaction rectification.The effect of raw material ratio,reaction distillation time,reflux ratio,the quantity of the catalyst and water⁃taking agent on esterification rate were investigated.The results show that the synthesis of isobutyl benzoate by reactive distillation can break through the restriction of chemical equilibrium in esterification process and improve the esterification rate.Additionally,the heat of reaction can be used synthetically and the azeotrope can be overcome to realize high precision separation.The optimal conditions are as follows:The mass of benzoic acid is 30 g,the molar ratio of isobutanol to benzoic acid is 5,the reflux ratio is 3,the mass ratio of catalyst to benzoic acid is 8.33%,the dosage of cyclohexane is 60 mL,and the reaction rectification time is 2 h.Under these conditions mentioned above,the esterification rate of benzoic acid can reach 82.7%,and the yield of isobutyl benzoate is up to 75.9%.