催化剂填料催化乙酸甲酯水解的动力学研究

采用间歇搅拌釜反应器在40~55的温度范围内以强酸性催化剂填料为催化剂研究了乙酸甲酯的水解动力学规律。实验在原料水与乙酸甲酯的摩尔配比0.5:1~2:1范围内考察了低水浓度时的动力学结果,并采用了较小的粉状催化剂颗粒和较高的搅拌速度以消除内外扩散阻力。实验结果分别用均相动力学模型和基于Langmuir- Hinshelwood 理论的非均相动力学模型进行拟合,得到了两者的模型参数。统计检验发现在水浓度不太高的条件下基于单点吸附理论的表面反应是最关键的控制步骤,此时用非均相动力学方程来拟合实验数据比较准确,而传统上采用的均相动力学方程拟合精度较差,只有在水浓度很高的条件下才能适用。

Hydrolysis Kinetics of Methyl Acetate Catalyzed by Catalytic Packing

A stirred batch reactor was used to study the hydrolytic kinetics of methyl acetate by using a catalyst which was usually used as catalytic packing in the packing tower. In order to eliminate the diffusion resistances, the experiments were conducted at high stirring speed and the fine grained catalyst was used. At the low molar ratio of water to methy1 acetate (0.5:1~2:1) and under the temperature range of 40~55C, the effect of water on the hydrolytic reaction rate was investigated. The experimental results were respectively analyzed by using homogeneous kinetics and heterogeneous models based on Langmuir- Hinshelwood rate expressions, the model parameters were obtained. It is found that the surface reaction between methyl acetate and water in the adsorbed state(single site mechanism) is rate-controlling step when the water concentrations is low, which is quite different from the traditional models based on homogeneous kinetics used for the reactions in which the water concentrations is high. The calculated data from the presented heterogeneous model agree well with the experimental results.