| 摘要 |
1522877 Producing chlor-alkali in diaphragm cell ASAHI GLASS CO Ltd 1 Oct 1976 [17 Oct 1975] 40976/76 Heading C7B Pure alkali metal hydroxide is produced by brine electrolysis in a chlor-alkali cell partitioned by a fluorinated copolymer cation exchange membrane having carboxylic acid (ion exchange) groups, the copolymer, e.g. produced by copolymerizing a fluorinated olefin monomer such as C 2 F 4 and a comonomer having carboxylic acid group (or functional group which can be converted thereto) such as CF 2 =CFO(CF 2 ) 3 COOCH 3 or CF 2 =CFOCF 2 CF(CF 3 ) OCF 2 CF 2 COOCH 3 in C 2 Cl 3 F 3 with catalyst of azobisisobutyronitrile, having an ion exchange capacity of 0À5 to 2À0 meq/g dry polymer, a concentration of carboxylic acid groups of 8 to 30 meq/g water absorbed in the membrane in the aqueous alkali metal hydroxide solution at the same concentration as that of catholyte, and preferably a glass transition temperature at least 20‹C lower than that of electrolysis. Acid is added to the anolyte to maintain it of acid condition higher than pH 1À3. |
