The aim of this research is to study the separation of a mixture with a methyl acetate synthesis reaction by pervaporation. The feed solutions that have compositions close to a chemical equilibrium are the main object of this work. The pervaporation of these solutions leads to the shifting of the composition from its chemical equilibrium. As a result, ester synthesis reaction coupled with pervaporation allows for more effective conversion of reagents. The hybrid process "reaction+pervaporation" was studied using membranes with a base of poly-(2,6-dimethyl-1,4-phenylene oxide) (PRO): a homogeneous PPO membrane and a composite membrane consisted of a PPO thin selective layer (similar to 5 mu m) on the surface of a ftuoroplastic composite hydrophobic membrane (MFFC). The transport properties of homogeneous and newly developed composite membranes based On the PRO were studied through the pervaporation of quaternary system acetic acid methanol and water methyl acetate. The sorption experiments were carried out to explain the pervaporation data. The possibility of using transformed composition variables for the analysis of pervaporation of mixtures in chemical equilibrium is demonstrated. It was shown that homogeneous and composite membranes are effective in shifting the esterification reaction equilibrium in pervaporation by the removal of methyl acetate or other esters from the reaction mixture. Composite membranes exhibited higher transport parameters (permeability and selectivity) than homogeneous membranes. (C) 2013 Elsevier Ltd. All rights reserved.