| 摘要 |
PURPOSE:To produce an aq. alkali hydroxide soln. having a high concn. with high current efficiency when an aq. alkali chloride soln. is electrolyzed in an electrolytic cell provided with an ion exchange membrane to produce an alkali hydroxide, by using a fluorine-contg. cation exchange membrane having a specified multilayered structure. CONSTITUTION:When an aq. soln. of an alkali chloride such as NaCl is electrolyzed in an electrolytic cell provided with a diaphragm, a fluorine-contg. cation exchange membrane consisting of a first layer of >=5mum thickness and a second layer of >=5mum thickness is used as the diaphragm to produce an aq. NaOH soln. having a high concn. of >=42%. The first layer is an alkali-proof cation exchanger made of a perfluorocarbon polymer having -SO3M or -OM groups (M is an alkali metal) and cotg. 20-60vol.% dispersed alkali-proof inorg. particles or short fibers of oxide, nitride, carbide, hydroxide or the like of a specified element. The second layer is an alkali-proof cation exchanger made of a perfluorocarbon polymer having -CO2M groups. The ion exchange capacity of the polymer of the second layer is 0.85-1.6 milliequiv. per 1g dry resin. The cation exchange membrane is stretched in the electrolytic cell so that the first layer confronts the cathode. |
