Pervaporation (PV) separation of ternary and quaternary mixtures of ethyl acetate (EAc), water, ethanol (EOH) and acetic acid (AsAc), which are present in the hydrolysis of ethyl acetate encountered in pharmaceutical industries was investigated. Water concentrations in the feed mixtures are in the range of 90-98 wt.%, while the concentrations of ethyl acetate, ethanol and acetic acid are much lower. Polydimethylsiloxane (PDMS) was used as membrane to separate organic compounds from aqueous streams. Pervaporation experiments were conducted at 30 degrees C. The effect of feed concentration on flux and selectivity was discussed. Experiments show that PDMS membrane is much more selective to ethyl acetate than other organic components. Increase in the ethyl acetate concentration in feed mixture yields higher total fluxes but lower selectivities of ethyl acetate. (c) 2006 Elsevier B.V. All rights reserved.