ENRICHING OR SEPARATING METHOD, COPOLYAMIDE AND COPOLYIMIDOAMIDE AND USE THEREOF

摘要

PURPOSE: To separate salts of organic carboxylic acids and organic compounds of non-salt character with good selectivity by using an aromatic copolyamide or copolyimide amide having introduced sulfonic acid groups as the material of a semipermeable membrane. CONSTITUTION: A non-substituted or 1-3C alkoxy substituted alkanol in which salts of organic carboxylic acids and organic compounds of non-salt character have been dissolved is brought into contact with one side of a semipermeable membrane of an aromatic copolyamide or copolyimide amide having introduced sulfonic acid groups. A pure solvent such as methanol is allowed to exist on the other side of the membrane. The copolyamide or copolyimide amide comprises a specified aromatic dicarboxylic acid radical and/or a specified aromatic tricarboxylic acid radical, a specified aromatic diamine radical and an aromatic diamine radical containing specified sulfonic acid groups. Each group of the copolymer is non-substituted or substituted by a halogen, nitro or the like.