Esterification of Acetic Acid by Flow-Type Membrane Reactor with AEI Zeolite Membrane.

AEI-type zeolite membrane for dehydration was prepared, and a flow-type membrane reactor for the esterification of acetic acid and ethanol by AEI membrane was developed. A synthesized AEI membrane had suitable molecular sieving property for gas separation (H 2 / i -butane and CO 2 /CH 4 ) and pervaporation (H 2 O/acetic acid). AEI membrane showed H 2 O permeance of 6.2 × 10 -7 mol m -2 s -1 Pa -1 with a separation factor of 67 at 363 K for the equimolar mixture of H 2 O/acetic acid. AEI membrane maintained stable performance under acidic conditions. The yield of ethyl acetate at 363 K in a flow-type membrane reactor with AEI membrane successfully exceeded the equilibrium of 69.1%, reaching 89.0%. The flow rate of feed solution strongly affected the conversion of acetic acid and the space-time yield (STY) of ethyl acetate. Due to the more significant proportion of water selectively removed from the reaction system at a lower feed flow rate, the thermodynamic equilibrium shifted significantly, resulting in higher conversions. In contrast, STY increased with increasing feed flow rate. Our flow-type membrane reactor exhibited a relatively large STY of 430 kg m -3 h -1 compared with the batch-type membrane reactor previously reported.