强酸性离子交换树脂催化合成乙酸正丁酯动力学

Kinetics of Catalytic Synthesis of n-butyl Acetate Using Strong Acid Ion Exchange Resin as Catalyst

为了获得D072型强酸性离子交换树脂催化剂合成乙酸正丁酯反应动力学方程，在间歇釜式反应器中，消除内外扩散后，测定不同反应条件下乙酸浓度随时间的变化，反应体系按拟均相处理，用初始速率法回归估算动力学模型参数。在催化剂平均粒度小于0．074mm，搅拌速度大于150r．min^-1时，可基本消除内外扩散的影响。在常压，催化荆用量为0．01665-0．08333gcut.gA-1，温度为326．2-358．2K的条件范围，获得的动力学模型参数为：k0=8．86×10^4L·mool-1min-j·gul-1，E,=60728．86J．mol-1，平衡常数受温度的影响不大。在实验条件范围对获得的动力学方程进行了验证，最大相对偏差小于8．3％，计算值与实验值符合较好。

In order to investigate the kinetics of using the strong acid ion exchange resin （D072） to catalytically synthesize the n-butyl acetate, the dependence of the acetic acid concentration change on reaction time during the liquid phase synthesis of n-butyl acetate was experimentally determined in a stirred batch reactor in the reaction temperature range of 326.2-358.2 K and mass ratio （catalyst/acetic acid） range of 0.01665-0.08333 gcat.gA-1 at 101.3 kPa. After eliminating the internal and external diffusions, the catalytic reaction system was treated as pseudo homogeneous phase, and the reaction kinetic parameters were obtained by the regression with the initial reaction rate method. The results show that the effects of external diffusion and internal diffusion could be eliminated when the stirred speed is more than 150 r.min-1 and the particle average size of catalyst is less than 0.074 mm. In the range of the selected experiment conditions, the obtained pre-exponential factor k0 in the kinetic equation is 8.86×10^4 L.mol-1.min-gcat-1 and the activation energy Ea is 60728.86 J-mol-1 It was found that the reaction equilibrium constant K depends on temperature weakly. Comparing the calculated values obtained by using the obtained kinetic equation with the corresponding measured values, the maximum deviation is less than 8.3%.