Asahi Kasei Kogyo Kabushiki Kaisha

Yasumichi Yamakoshi

Hirotsugu Miyauchi

Itaru Watanabe

Maomi Seko

Kyoji Kimoto

Mitsunobu Fukumoto

Sakae Tsushima

Toshioki Hane

Masato Hamada

Yoshinori Masuda

Fumihiko Yamamoto

Shigeo Yokoyama

Naomi Seko

An electrolytic cell having anode and cathode chambers separated by a cation exchange membrane comprising a fluorocarbon polymer containing pendant carboxylic acid or salt groups of the formula ##STR1## wherein R is a group containing perfluoroalkyl or perfluoroalkoxy having 1 to 5 carbon atoms and M is hydrogen, an alkali or alkaline earth metal or ammonium as a surface stratum on the cathode side of the membrane. The fluorocarbon polymer may also contain sulfonic acid groups of the formula ##STR2##

Electrolysis of aqueous alkali metal halide solution

Cation exchange membrane comprising a fluorocarbon polymer characterized by the presence of pendant carboxylic acid groups of the formula -- OCF.sub.2 COOH -- and derivatives thereof.

Cation exchange membrane preparation and use thereof

A fluorocarbon polymer membrane having pendant sulfonamide groups is first treated with anion radicals and then hydrolyzed for conversion into a cation exchange membrane having carboxylic groups and sulfonic acid groups.

Method for preparation of cation exchange membranes

An aqueous alkali metal halide solution is electrolyzed in an electrolytic cell using a cation exchange membrane which is a fluorocarbon polymer containing sulfonic acid groups and at least one cation exchange group which is less acidic than the sulfonic acid group with higher proportion of the latter in surface stratum on the cathode side of the membrane than in the entire membrane, while controling proton concentration in the anolyte at not higher than critical proton concentration at which no substantial amount of protons in the anolyte penetrate into the membrane.

Process for electrolysis of aqueous alkali metal halide solution

A perfluorocarbon type cation exchange membrane prepared by treatment with an oxidizing agent of a cation exchange membrane containing perfluorocarbon polymers having specific pendant N-sulfonamide groups has improved electrochemical characteristics when used as a membrane in electrolysis of aqueous alkali halide solution.

Process for production of perfluorocarbon type cation exchange membrane

A leno-woven fabric of a specific construction is found to effectively reinforce an ion-exchange membrane at a scarce density of reinforcing yarns to improve electrochemical property of the reinforced ion-exchange membrane.

Growing community of inventors

Tokyo, Japan

Yasumichi Yamakoshi