Preparation of high-flux mordenite membranes and the application to esterification of acetic acid

High-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.