Claims
- 1. In an ion exchange membrane cell which comprises an anode, a cathode, and an anode compartment and a cathode compartment partitioned by an ion exchange membrane, an improvement characterized in that said ion exchange membrane is a cation exchange membrane having a gas and liquid permeable porous non-electrode layer on at least one side thereof and said cation exchange membrane is a membrane of a fluorinated cation exchanger having carboxylic acid groups as its ion exchange groups and with its ion exchange capacity being varied in the direction of its thickness.
- 2. The ion exchange membrane cell according to claim 1 wherein the gas and liquid permeable porous layer is formed by an electrically conductive or non-conductive inorganic or organic material and applied in an amount of from 0.001 to 100 mg/cm.sup.2.
- 3. The ion exchange membrane cell according to claim 1 or 2 wherein the ion exchange capacity of the cation exchange membrane is continuously or stepwise decreased from the anode side toward the cathode side within a range of from 0.5 to 2.5 milliequivalent/gram dry polymer.
- 4. The ion exchange membrane cell according to claim 1, 2, or 3 wherein the ion exchange capacity of the cation exchange membrane is varied so that the maximum difference in the ion exchange capacity is from 0.1 to 1.0 milliequivalent/gram dry polymer.
- 5. The ion exchange membrane cell according to any one of claims 1 to 4 wherein said cation exchange membrane is formed by laminating at least two fluorinated polymer films having carboxylic acid groups having different ion exchange capacities so that the ion exchange capacity on the cathode side is smaller than that on the anode side.
- 6. The ion exchange membrane cell according to any one of claims 1 to 5 wherein said cation exchange membrane is made of a fluorinated polymer film having carboxylic acid groups and the ion exchange capacity on the cathode side is made smaller than that on the anode side.
- 7. In an electrolytic cation exchange membrane having a gas and liquid permeable porous non-electrode layer on at least one side thereof, an improvement characterized in that said cation exchange membrane is formed by a fluorinated cation exchanger having carboxylic acid groups as its ion exchange groups and with its ion exchange capacity being varied in the direction of its thickness.
- 8. The electrolytic cation exchange membrane according to claim 7 wherein the gas and liquid permeable porous layer is formed by an electrically conductive or non-conductive inorganic or organic material and applied in an amount of from 0.005 to 50 mg/cm.sup.2.
- 9. The electrolytic cation exchange membrane according to claim 8 wherein said inorganic material is composed of a single substance, an alloy, an oxide, a hydroxide, a nitride or a carbide of a metal of Group IV-A, VI-B or V-B of the Periodic Table, an iron group metal, chromium, manganese or boron.
- 10. The electrolytic cation exchange membrane according to claim 7 wherein the organic material is a fluorinated resin, a polyamide resin, a polysulfonic resin, a polyphenyleneoxide resin, a polyphenylenesulfide resin, a polypropylene resin, or a polyimide resin.
- 11. The electrolytic cation exchange membrane according to any one of claims 7 to 10 wherein the ion exchange capacity of the cation exchange membrane is continuously or stepwise decreased from the anode side toward the cathode side within a range of from 0.5 to 2.5 milliequivalent/gram dry polymer.
- 12. The electrolytic cation exchange membrane according to claim 7 or 11 wherein the ion exchange capacity of the cation exchange membrane is varied so that the maximum difference in the ion exchange capacity is from 0.1 to 1.0 milliequivalent/gram dry polymer.
- 13. The electrolytic cation exchange membrane according to claim 7, 11 or 12 wherein the fluorinated cation exchanger is formed by laminating at least two fluorinated polymer films having carboxylic acid groups having different ion exchange capacities.
- 14. The electrolytic cation exchange membrane according to claim 7, 11 or 12 wherein the fluorinated cation exchanger is made of a fluorinated polymer film having carboxylic acid groups and the ion exchange capacity on one side is smaller than that on the other side.
- 15. The ion exchange membrane according to any one of claims 7 to 14 wherein said fluorinated polymer has recurring units (a) and (b), ##STR3## wherein X represents a fluorine, chlorine or hydrogen atom or --CF.sub.3 ; X' represents X or CF.sub.3 (CF.sub.2).sub.m ; m represents an integer of 1 to 5; Y represents the following unit; ##STR4## x, y and z respectively represent an integer of 1 to 10; z and Rf represent --F or a C.sub.1 -C.sub.10 perfluoroalkyl group; and A represents --COOM or --SO.sub.3 M or a functional group which is convertible into --COOM or --SO.sub.3 M by hydrolysis or neutralization such as --CN, --COF, --COOR.sub.1 or --SO.sub.2 F and M represents hydrogen or an alkali metal atom.
- 16. In a process for electrolyzing an aqueous solution of an electrolyte in an electrolytic cell comprising, an anode, a cathode, and an anode compartment and a cathode compartment partitioned by an ion exchange membrane, an improvement characterized in that said ion exchange membrane is a cation exchange membrane having a gas and liquid peameable porous non-electrode layer on at least one side thereof and said cation exchange membrane is a membrane of a fluorinated cation exchanger having carboxylic acid groups as its ion exchange groups and with its ion exchange capacity being varied in the direction of its thickness.
- 17. The process according to claim 16 wherein said electrolyte is an alkali metal chloride.
- 18. The process according to claim 17 wherein said electrolysis is performed by feeding an aqueous solution of an alkali metal chloride having a concentration of 2.5 to 5.0N into said anode compartment at a temperature of 60.degree. to 120.degree. C. at a current density of 10 to 100 A/dm.sup.2.
- 19. The process according to claim 18 wherein water or a dilute aqueous solution of a base is fed into said cathode compartment to obtain an aqueous solution of an alkali metal hydroxide having a concentration of 20 to 50 wt.%.
- 20. The process according to claim 16 wherein electrolyte is water, an acid, a base or an alkali metal carbonate.
Parent Case Info
This application is a continuation in part of application Ser. No. 205,567, filed Nov. 10, 1980, and a continuation in part of Application Ser. No. 355,312 filed Mar. 5, 1982.
US Referenced Citations (6)
Foreign Referenced Citations (1)
Number |
Date |
Country |
1120003 |
Mar 1979 |
CAX |
Continuation in Parts (1)
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Number |
Date |
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Parent |
205567 |
Nov 1980 |
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