酶法制备一氯乙酸对硝基苄酯及催化反应动力学模型

研究了固定化脂肪酶Novozym 435催化对硝基苄醇和一氯乙酸制备一氯乙酸对硝基苄酯的过程,并对酶法合成反应条件进行优化,确定最佳反应条件为:甲苯作溶剂,对硝基苄醇与一氯乙酸摩尔比1:2,对硝基苄醇浓度5 g L 1,Novozym 435脂肪酶浓度为3.4 g L 1,反应温度50℃,反应时间10 h,对硝基苄醇转化率为76.7%。最后探索酶催化合成一氯乙酸对硝基苄酯动力学反应,得出该反应动力学模型符合双底物乒乓机理和一氯乙酸底物抑制动力学模型的结论并写出了其动力学方程。

Synthesis of 4-Nitrobenzyl 2-Chloroacetate by Enzymatic Method and its Lipase-Catalyzed Kinetic Model

The synthesis of 4-nitrobenzyl 2-chloroacetate by using the 4-nitrobenzyl alcohol and chloroacetic acid as raw materials and immobilized lipase Novozym 435 as catalyst was investigated.The reaction conditions of enzymatic synthesis were also optimized,and the optimum conditions found are as follows: mole ratio of 4-nitrobenzyl alcohol and chloroacetic acid is 1:2,concentration of 4-nitrobenzyl alcohol is 5 g L 1,Novozym 435 concentration is 3.4 g L 1,reaction temperature is 50℃ and reaction time is 10 h.Under above optimum conditions,the yield of 4-nitrobenzyl 2-chloroacetate can reach 76.7%.In addition,the kinetics of lipase catalytic synthesis of 4-nitrobenzyl 2-chloroacetate was explored,and it was found that the kinetics of the reaction agrees with the double-substrate ping-pong procedure mechanism and acid-substrate inhibition kinetic model.Finally,the kinetic equation of the model was given.