Cation exchange membrane and use thereof in the electrolysis of sodium chloride

A process for the electrolysis of an aqueous sodium chloride solution which comprises passing an electric current through said solution in an electrolytic cell separated into an anode chamber and a cathode chamber by a cation exchange membrane at a temperature of 0.degree. to 150.degree. C. while charging an aqueous sodium chloride solution which has been purified to a calcium content of less than 1 p.p.m. into the anode chamber and adding water or an aqueous dilute sodium hydroxide solution into the cathode chamber to adjust the concentration of sodium hydroxide therein to more than 20%, said membrane consisting essentially of perfluorocarbon polymer having pendant carboxylic acid and sulfonic acid groups, the ion exchange capacity of sulfonic and carboxylic acid groups being from 0.5 to 2.21 milliequivalents per gram of dry resin, the ratio of carboxylic acid groups to sulfonic acid groups being in the range of from 1:100 to 100:1.

A cation exchange membrane suitable for use in the electrolysis of an aqueous sodium chloride solution consisting essentially of perfluorocarbon polymer having pendant carboxylic acid and sulfonic acid groups, the ion exchange capacity of sulfonic and carboxylic acid groups being from 0.5 to 2.21 milliequivalents per gram of dry resin, the ratio of carboxylic acid groups to sulfonic acid groups being in the range of 1:100 to 100:1.

An electrolytic cell comprising an anode chamber and a cathode chamber separated by a cation exchange membrane which is suitable for the production of aqueous sodium hydroxide in the cathode chamber wherein an aqueous solution of sodium chloride is charged into the anode chamber, said membrane consisting essentially of perfluorocarbon polymer having pendant carboxylic acid and sulfonic acid groups, said membrane having an ion exchange capacity of sulfonic and carboxylic acid groups of from 0.5 to 2.21 milliequivalents per gram of dry resin, the ratio of carboxylic acid groups to sulfonic acid groups being in the range of 1:100 to 100:1.

A process for the electrolysis of an aqueous sodium chloride solution with high current efficiency at high concentrations of sodium hydroxide which comprises passing an electric current through said solution in an electrolytic cell separated into an anode chamber and a cathode chamber by a cation exchange membrane consisting essentially of perfluorocarbon polymer having pendant carboxylic acid and sulfonic acid groups, the ion exchange capacity of sulfonic and carboxylic acid groups being from 0.5 to 2.21 milliequivalents per gram of dry resin.

A cation exchange membrane suitable for use in the electrolysis of an aqueous sodium chloride solution consisting essentially of perfluorocarbon polymer having pendant carboxylic acid and sulfonic acid groups, the ion exchange capacity of sulfonic and carboxylic acid groups being from 0.5 to 2.21 milliequivalents per gram of dry resin, said membrane providing high current efficiency at high concentrations of sodium hydroxide.

An electrolytic cell comprising an anode chamber and a cathode chamber separated by a cation exchange membrane which is suitable for the production of aqueous sodium hydroxide in the cathode chamber wherein an aqueous solution of sodium chloride is charged into the anode chamber, said membrane consisting essentially of perfluorocarbon polymer having pendant carboxylic acid and sulfonic acid groups, said membrane having an ion exchange capacity of sulfonic and carboxylic acid groups of from 0.5 to 2.21 milliequivalents per gram of dry resin, said membrane providing high current efficiency at high concentrations of sodium hydroxide.