A pervaporation process for separating organic liquid mixtures of components
having
differing polarities, uses an ion exchange membrane which comprises a polymerized
alkene including pendant groups of formula SO2N(R)-A-QX where R is H
or alkyl, A is alkylene, Q is quaternary ammonium, and X is a negatively-charged
counter-ion, the sulfur content of the membrane being in the range 3-10 wt. %.
