| 摘要 |
PURPOSE:To produce an alkali hydroxide soln. having a relatively high concn. with small consumption of energy by electrolyzing an alkali chloride under specified conditions with a fluorine-contg. cation exchange membrane composed of specified two kinds of perfluorocarbon polymers. CONSTITUTION:A fluorine-contg. cation exchange membrane consisting of a first layer of a perfluorocarbon polymer having -SO3M groups (M is an alkali metal) and a second layer of a perfluorocarbon polymer having -CO2M groups (M is an alkali metal) is stretched in an electrolytic cell so that the first layer confronts the cathode. The thickness of each of the layers is >=5mum, the hydration rate of the second layer in 45wt.% aq. NaOH soln. is 2-7wt.% and the hydration rate of the first layer is higher than that of the second layer by about 3-30%. About 2.5-5.0N alkali chloride soln. is fed to the anode chamber of the cell, water or a dil. aq. alkali hydroxide soln. to the cathode chamber and electrolysis is carried out preferably at about 50-120 deg.C and about 5-100A/dm<2> current density. Thus, an alkali hydroxide soln. having >=about 45wt.% concn. is produced with high current efficiency. |
