高通量MOR型分子筛膜的制备及在乙酸酯化反应中的应用

采用含氟体系制备了高性能MOR型分子筛膜。采用XRD和SEM表征了MOR型分子筛膜及其参与8次酯化反应后膜层的微观结构。将高通量MOR型分子筛膜用于Zr(SO₄)₂/H-β催化的乙酸与乙醇酯化反应，基于2级动力学假设建立了膜反应器中进行的酯化反应动力学模型，考察了醇/酸摩尔比、催化剂用量和反应温度，以及MOR型分子筛膜的重复使用对乙酸转化率的影响。结果表明，含氟体系与无氟体系相比，所制备的MOR型分子筛膜的渗透通量可提高1.4倍。动力学模型模拟结果与实验数据吻合良好。MOR型分子筛膜反应器打破了乙酸酯化反应的化学平衡，由于生成的水可通过膜分离移出反应体系，反应12 h后乙酸几乎完全转化，同时分子筛膜重复使用8次对乙酸转化率无明显影响。

Preparation of High-Flux Mordenite Membranes and the Application to Esterification of Acetic Acid

Hig-performance mordenite membranes were prepared in the fluoride media. The microstructures of mordenite membranes before and after eight esterification runs were characterized by X-ray diffraction (XRD) and scanning electronic microscope (SEM). The high-flux mordenite membrane was applied to the esterification of acetic acid with ethanol over Zr(SO₄)₂/H-β heterogeneous catalyst. The esterification kinetics model in the membrane reactor was built up based on the assumption that the reaction obeyed second-order kinetics. Esterification conditions, such as molar ratio of ethanol to acetic acid, catalyst usage and reaction temperature were optimized. The effect of the reuse of mordenite membrane on the conversion of acetic acid was also investigated. The results showed that the flux of mordenite membrane prepared in fluoride media increased by 1.4 times comparing with that prepared in nonfluoride media. The kinetic model was in a good agreement with the experimental data. The convention of acetic acid esterified in mordenite membrane reactor arrived at almost 100% after 12 h by removing water from the reaction, and was not obviously changed after eight reaction runs of esterification with one membrane.