Methanol selective membranes for separation of methanol-ethylene glycol mixtures by pervaporation

Abstract

Several copolymers of acrylonitrile were synthesized. Methanol selective membranes were prepared from these copolymers of acrylonitrile. The other monomers in the copolymers were selected on the basis of their solubility parameter values relative to those of methanol. These were hydroxy ethyl methacrylate, methacrylic acid and vinyl pyrrolidone. Thus, pervaporative separation of methanol from its mixture with ethylene glycol over the entire concentration range 0-100% methanol was studied using these copolymer membranes of acrylonitrile. For each copolymer of acrylonitrile three different membranes with different copolymer compositions were prepared. Copolymers of acrylonitrile with hydroxy ethyl methacrylate and methacrylic acid showed good selectivity and moderate flux for methanol (14.74, 11.3 and 0.108 kg/m² h, 0.0813 kg/m² h, respectively, with membrane of 50 μm thickness for feed mixture containing 50% methanol). Copolymer of acrylonitrile with vinyl pyrrolidone showed comparable flux but methanol selectivity of this membrane was poor.