Pervaporation method of selectively separating water from an organic material aqueous solution through aromatic imide polymer asymmetric membrane

摘要

A pervaporation separation method of water from an organic material aqueous solution at a high separating efficiency is effected by using a specific asymmetric separating membrane comprising a heat-resistant, solvent-soluble aromatic imide polymer prepared by the polymerization and imidization of an aromatic tetracarboxylic acid component comprising, as a principal ingredient, at least one biphenyl tetracarboxylic acid compound with an aromatic diamine component comprising a principal member selected from: <IMAGE> (I) and <IMAGE> (II) and an additional member selected from another aromatic diamine compounds having 2 to 5 benzene ring structures and different from the diamine compounds (I) and (II).