Mixed matrix membranes (MMM) containing MOF Cu3(BTC)2 (HKUST-1) at 20–40 wt% loading have been prepared using commercial polyimide (PI) Matrimid® 5218 as polymer matrix. With the addition of this hydrophilic MOF, the water/ethanol separation via pervaporation was improved by increasing the water flux from 0.24 kg m−2 h−1 for bare PI up to 0.43 kg m−2 h−1 with 40 wt% Cu3(BTC)2 MMM without significant changes in the separation factor (>200). Due to their selective water permeation, these MMMs have been used to displace equilibrium in the esterification of acetic acid with ethanol. By coupling separation by membrane and the reaction in the same device, the conversion obtained at the same feed rate and catalyst loading was higher than that achieved without any membrane. At 70 °C the membrane reactor reached a conversion of 70%, higher than the equilibrium value (66%).