Application of a mordenite membrane to the esterification of acetic acid and alcohol using sulfuric acid catalyst

Abstract

The well acid-stable and hydrophilic mordenite membrane is applied as a “membrane extractor reactor” for the esterification of acetic acid and alcohol with the H2SO4 as catalyst. The mordenite membrane reactors are placed into the reaction mixtures and continuously remove water from the esterification mixture by pervaporation, which could greatly improve the alcohol conversions of esterification. Besides, the effects of the reaction conditions (such as temperature, molar ratio of acetic acid/alcohol, and catalyst loading) on the ethanol conversion are investigated in details. As the reactional temperature, the molar ratio of acetic acid/alcohol, the catalyst loading, and the ratio of effective membrane surface area to esterification mixture volume are 85 °C, 1.5, 0.05 wt% (0.005 mol/L), and 0.31 cm2/cm3, the ethanol and n-butanol conversions of esterifications are up to 98.13% and 98.73%, respectively. Even if the mordenite membrane is applied to pervaporation-esterification for 8 times (96 h), the mordenite membranes are still kept the typical diffraction peaks and morphology by XRD and SEM characterization, and the dehydration performance of the membrane for 90 wt% HAc/H2O mixture at 75 °C is almost the same as the as-synthesized mordenite membranes, and the flux and separation factor of the mordenite membrane after 8 times PV-esterification are 0.44 kg m−2 h−1 and 627.