Pervaporative dehydration of acetic acid, ethyl alcohol, isopropyl alcohol, and acetone over the entire concentration range of 0-100 wt% is studied using acrylonitrile-maleic anhydride copolymer membrane. The membrane exhibits reasonable performance with respect to both separation factor and permeance (11.0 and 279.4 g/m(2).hr./bar, respectively, at 92 wt% feed conc. of water) for acetone dehydration. Dehydration performances of acetic acid and ethyl alcohol are comparable (permeance and separation factor of water for its mixture with acetic acid is 119.5 gm/m(2).hr./bar and 2.4, respectively, while the same for its mixture with ethyl alcohol is 125.4 gm/m(2).hr./bar and 2.5, respectively, at 50 wt% feed) over the whole concentration range. Isopropyl alcohol shows the best separation factor for water at very low alcohol concentration (8.7 at 2.5 wt% feed) with lowest permeance among the four systems of separations.