固定化酶催化制备乙酸正丁酯及动力学

酯交换反应可用南极假丝酵母脂肪酶B（CALB）作催化剂，采用溶胶-凝胶法固定脂肪酶CALB得到的催化剂颗粒可用于乙酸乙酯和正丁醇的酯交换反应。首先探究了固定化酶的稳定性和重复使用性，然后在间歇反应釜内进行反应动力学实验，考察了转速、催化剂用量、酯醇比、温度等因素对反应的影响，确定了适宜的操作条件。在328.15～343.15 K下，将实验数据拟合得到反应的动力学方程，通过实验值与计算值的比较，验证此宏观动力学方程合理，可用于模拟计算。

Kinetics of n-butyl acetate prepared by immobilized enzyme

Candida antarctica lipase B(CALB) is immobilized by entrapment in a hydrophobic silica xerogel. Firstly, the stability and reuse of immobilized enzymes are investigated and can be stored for at least 40 d at 25℃ without any significant loss of enzyme activity. Then, the transesterification of ethyl acetate with n-butanol in the presence of immobilized CALB is considered in a batch stirred tank reactor. The reaction kinetics is experimentally determined for different stirring rate, catalyst dosage, concentration and temperature. The suitable operating conditions are determined and a pseudo homogeneous kinetic model is established. The calculation data are in better agreement with the experimental data which shows that the kinetic equations are reasonable and suitable for simulation calculation.