Electrolytic cell and method

Abstract

Chlorine and other halogens can be generated by electrolyzing an aqueous alkali metal halide or hydrogen halide between an anode and cathode in an electrolytic cell having a composite semipermeable membrane separating the said electrodes. This membrane is in sheet form and normally comprises a layer, coating or sheet of a fluorocarbon having cation exchange groups disposed on the anode side and a second layer, coating or sheet on the cathode side which is non-fluorinated or is less fluorinated and consequently more hydrophilic (less hydrophobic) than the first layer and which also has cation exchange groups i.e. acid groups or alkali metal salts thereof attached thereto. The less fluorinated cathodic side apparently releases evolved hydrogen more readily than does the more heavily fluorinated anode layer, particularly when the cathode is in contact with or bonded to and/or embedded in the membrane. The cathode is maintained close enough to the cathode side of the membrane to maintain the more hydrophilic second layer alkaline during the electrolysis and the two layers may be bonded together or may be installed together and in contact with each other without bonding.

Dependencies are inferred from the claim text.