CIESC Journal ›› 2020, Vol. 71 ›› Issue (11): 5178-5187.DOI: 10.11949/0438-1157.20200186

• Catalysis, kinetics and reactors • Previous Articles     Next Articles

Kinetics of esterification of glycerol with acetic acid catalyzed by pyridine bisulfate ionic liquid

Hao XU(),Yang LI,Chengkang XIA,Ruining HE,Yun ZOU,Zhangfa TONG()   

  1. Guangxi Key Laboratory of Petrochemical Resource Processing and Process Intensification Technology, School of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004, Guangxi, China
  • Received:2020-02-25 Revised:2020-05-24 Online:2020-11-05 Published:2020-11-05
  • Contact: Zhangfa TONG

吡啶硫酸氢盐离子液体催化甘油与乙酸酯化反应动力学

徐浩(),李洋,夏成康,何瑞宁,邹昀,童张法()   

  1. 广西石化资源加工及过程强化技术重点实验室,广西大学化学化工学院,广西 南宁 530004
  • 通讯作者: 童张法
  • 作者简介:徐浩(1993—),男,硕士研究生,2468444645@qq.com
  • 基金资助:
    广西自然科学基金重点项目(2017GXNSFDA198047);广西自然科学基金创新团队项目(2016GXNSFGA380003);广西石化资源加工及过程强化技术重点实验室主任基金(2019Z010)

Abstract:

Using pyridine bisulfate ionic liquid as a catalyst, the kinetic behavior of glycerol and acetate into triacetin was systematically studied. The effects of reaction temperature, molar ratio of acid to alcohol, and amount of catalyst on glycerol conversion and triacetin yield were investigated using single factor experiments. The reaction kinetic model was developed using the quasi-homogeneous first-order reaction theory. The pre-exponential factor and the reaction activation energy were obtained by fitting the kinetic experimental data. The results showed that the conversion of glycerol increased with increasing of reaction temperature and the molar ratio of acetic acid to glycerol. With the increase of the amount of catalyst, the reaction rate of glycerol increased gradually, but the equilibrium conversion remained essentially unchanged. Under the optimum reaction conditions of temperature at 110℃, the molar ratio of acetic acid to glycerol in 6∶1 and the catalyst dosage of 3%, the maximum conversion of glycerol and the maximum yield of glycerol triacetate were 98.5% and 40.4% respectively. The pre-exponential factors k10, k20 and k30 of glycerol with acetic acid gradually forming monoacetin, diacetin and triacetin were 7.17, 14.19 and 13.78 min-1 respectively. The corresponding reaction activation energies E1, E2 and E3 were 19.10, 21.58 and 23.25 kJ·mol-1 respectively. The calculated values by the kinetic model were agreed well with the experimental values. The catalyst has a better catalytic effect than that of the reported Amberlyst-15 and heteropoly acid catalyst with milder reaction conditions, higher selectivity, and lower activation energy.

Key words: ionic liquid catalyst, pyridine bisulfate, kinetic model, esterification, triacetin

摘要:

以吡啶硫酸氢盐离子液体为催化剂,系统研究其催化甘油和乙酸酯化反应生成三乙酸甘油酯的动力学行为。采用单因素实验考察反应温度、酸醇摩尔比、催化剂用量等因素对甘油转化率及产物三乙酸甘油酯收率的影响。根据拟均相一级反应机理建立微分方程组模型,通过动力学数据拟合获得指前因子和反应活化能。结果表明:甘油转化率随反应温度、酸醇摩尔比升高而增加;随着催化剂用量的增加,甘油的反应速率逐渐增大,但平衡转化率基本不变。当反应温度为110℃,乙酸/甘油摩尔比为6∶1,催化剂用量为甘油的3%(质量分数)时,甘油转化率最高为98.5%,三乙酸甘油酯收率最高为40.4%。甘油与乙酸反应逐步生成单乙酸甘油酯、二乙酸甘油酯、三乙酸甘油酯的指前因子k10k20k30分别为7.17、14.19、13.78 min-1,其相应的反应活化能E1、E2、E3分别为19.10、21.58、23.25 kJ·mol-1,该动力学模型计算值与实验值吻合较好。该催化剂相较于已报道的Amberlyst-15、杂多酸催化剂反应条件更温和、选择性更高、反应活化能更小,具有更好的催化效果。

关键词: 离子液体催化剂, 吡啶硫酸氢盐, 动力学模型, 酯化反应, 三乙酸甘油酯

CLC Number: