| 摘要 |
PURPOSE:To increase current efficiency in the electrolysis of an aqueous solution to produce high concn. caustic soda, etc., by using a diaphragm consisting of an exchange membrane made from perfluorocarbon polymer with a side chain of a specified structure. CONSTITUTION:The titled catin exchange membrane contains a perfluorocarbon polymer with a side chain of the fomula (wherein M is H, metal or NH4 group; Y is F or trifluoromethyl group; n is 0-30). The side chain enables the membrane to check diffusion of OH<-> from a cathode chamber in the electrolysis of salt water and this makes it possible to perform electrolysis at a high current efficiency even when NaOH is produced in the cathode chamber in high concn. This is because a carboxylic acid group present in the membrane esp. in the surface layer facing the cathode chamber, is less hydrophilic than a sulfonic acid group and prevents diffusion of OH<->. The high density of the carboxylic acid group reduces electric resistance of the membrane leading to operation at a high current density and efficiency. |
