Claims
- 1. 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 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 4.0 milliequivalents per gram of dry resin, the ion exchange capacity of the carboxylic acid groups being from 0.05 to 1.5 milliequivalents per gram of dry resin.
- 2. The process of claim 1, wherein the perfluorocarbon polymer having pendant carboxylic acid groups is present on the surface of the membrane.
- 3. The process of claim 1, wherein a perfluorocarbon polymer having pendant carboxylic acid groups is present on one surface of the membrane.
- 4. The process of claim 1, wherein a perfluorocarbon polymer having pendant carboxylic acid groups is present, together with a perfluorocarbon polymer having pendant sulfonic acid groups, on one surface of the membrane.
- 5. The process of claim 4, wherein a perfluorocarbon polymer having pendant sulfonic acid groups is present on another surface of the membrane.
- 6. The process of claim 1, wherein the membrane in the sodium salt form has a water content of from 5 to 50% by weight.
- 7. The process of claim 1, wherein said membrane comprises a physical combination of perfluorocarbon polymer having pendant carboxylic acid groups with perfluorocarbon polymer having pendant sulfonic acid groups.
- 8. The process of claim 1, wherein the cation exchange membrane is fiber reinforced.
- 9. The process of claim 1, wherein said perfluorocarbon polymer is a copolymer of at least one of tetrafluoroethylene and CF.sub.2 .dbd.CF--O--R.sub.f wherein R.sub.f is a perfluorinated alkyl group containing 1 to 3 carbon atoms with perfluorocarbon vinyl monomers containing carboxylic acid groups and sulfonic acid groups or functional groups which can be converted to carboxylic acid or sulfonic acid groups.
- 10. The process of claim 1, wherein said perfluorocarbon polymer is a copolymer of a perfluorocarbon vinyl monomer having the general formula:
- CF.sub.2 .dbd.CF--O--(CF.sub.2).sub.n --X
- wherein n is an integer of 2 to 12, and X is CN, COF, COOH, COOR, COOM or CONR.sub.2 R.sub.3 where R is an alkyl group containing 1 to 10 carbon atoms, R.sub.2 and R.sub.3 are individually hydrogen or an alkyl group containing 1 to 10 carbon atoms, and M is sodium, potassium or cesium; and a perfluorocarbon sulfonyl fluoride having the general formula:
- F--SO.sub.2 --CFR.sub.g --CF.sub.2 --O(CFYCF.sub.2 O).sub.m --CF.dbd.CF.sub.2
- wherein R.sub.g is fluorine or a perfluoroalkyl group having 1 to 10 carbon atoms, Y is fluorine or a trifluoromethyl group, and m is an integer of 1 to 3, with at least one of tetrafluoroethylene and CF.sub.2 .dbd.CF--O--R.sub.f wherein R.sub.f is a perfluorinated alkyl group containing 1 to 3 carbon atoms, which copolymer is hydrolyzed, if necessary, to form said acid groups.
- 11. The process of claim 1, wherein said perfluorocarbon polymer is a copolymer of a perfluoroacrylic acid having the general formula:
- CF.sub.2 .dbd.CF--COZ
- wherein Z is fluorine, an alkoxy group containing 1 to 10 carbon atoms, amino or hydroxy; and a perfluorocarbon sulfonyl fluoride having the general formula:
- F--SO.sub.2 --CFR.sub.g --CF.sub.2 --O(CFYCF.sub.2 O).sub.m --CF.dbd.CF.sub.2
- wherein R.sub.g is fluorine or a perfluoroalkyl group having 1 to 10 carbon atoms, Y is fluorine or a trifluoromethyl group, and m is an integer of 1 to 3, with at least one of tetrafluoroethylene and CF.sub.2 .dbd.CF--O--R.sub.f wherein R.sub.f is a perfluorinated alkyl group containing 1 to 3 carbon atoms, which copolymer is hydrolyzed, if necessary, to form said acid groups.
- 12. The process of claim 1, wherein said cation exchange membrane is prepared by impregnating or coating a membrane of a copolymer of (A) a perfluorovinyl ether having the general formula:
- LSO.sub.2 CFR.sub.g CF.sub.2 O(CFYCF.sub.2 O).sub.m --CF.dbd.CF.sub.2
- wherein L is hydroxy, fluorine or OA, where A is a quaternary ammonium radical; R.sub.g is fluorine or a perfluoroalkyl group having 1 to 10 carbon atoms; Y is fluorine or a trifluoromethyl group; and m is an integer of 1 to 3, and (B) at least one of tetrafluoroethylene and CF.sub.2 .dbd.CFOR.sub.f wherein R.sub.f is a perfluorinated alkyl group containing 1 to 3 carbon atoms, with a perfluorovinyl compound having pendant carboxylic acid groups or derivatives thereof, polymerizing said impregnated or coated vinyl compound, and hydrolyzing, if necessary, to form said acid groups.
- 13. The process of claim 12, wherein said perfluorovinyl compound is at least one member selected from the group consisting of compounds having the formula:
- CF.sub.2 .dbd.CF--O--(CF.sub.2).sub.n --X
- wherein n is an integer of 2 to 12, and X is CN, COF, COOH, COOR, COOM or CONR.sub.2 R.sub.3, where R is an alkyl group containing 1 to 10 carbon atoms, R.sub.2 and R.sub.3 are individually hydrogen or an alkyl group containing 1 to 10 carbon atoms, and M is sodium, potassium or cesium, and compounds having the formula:
- CF.sub.2 .dbd.CF--COZ
- wherein Z is fluorine or an alkoxy group containing 1 to 10 carbon atoms.
- 14. The process of claim 1, wherein said cation exchange membrane is prepared by impregnating or coating a membrane of a copolymer of (A) a perfluorovinyl ether having the general formula:
- LSO.sub.2 CFR.sub.g CF.sub.2 O(CFYCF.sub.2 O).sub.m --CF.dbd.CF.sub.2
- wherein L is hydroxy, fluorine or OA, where A is a quaternary ammonium radical; R.sub.g is fluorine or a perfluoroalkyl group having 1 to 10 carbon atoms; Y is fluorine or a trifluoromethyl group; and m is an integer of 1 to 3, and (B) at least one of tetrafluoroethylene and CF.sub.2 .dbd.CFOR.sub.f wherein R.sub.f is a perfluorinated alkyl group containing 1 to 3 carbon atoms, with a solution of a perfluorocarbon polymer having pendant carboxylic acid groups or derivatives thereof, and hydrolyzing, if necessary, to form said acid groups.
- 15. A process according to claim 12, 13 or 14, wherein the impregnating or coating is conducted on one surface of the membrane.
- 16. The process of claim 3, wherein said carboxylic acid groups are contained predominantly on said one surface of the membrane and wherein the membrane is disposed in said electrolytic cell such that said surface having the pendant carboxylic acid groups faces the cathode side of the cell.
- 17. A process according to claim 9, 10, 11, 12, 13 or 14, wherein the cation exchange membrane is fiber reinforced.
- 18. The process of claim 1, wherein the thickness of the membrane is 0.05 to 1.5 mm.
- 19. The process of claim 1, wherein the electrolysis is conducted at a temperature of 0.degree. to 150.degree. C. while charging an aqueous sodium chloride solution 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 to more than 20%.
- 20. The process of claim 1, wherein the membrane has an ion exchange capacity of sulfonic and carboxylic acid groups of from about 0.88 to about 2.21 milliequivalents per gram of dry resin.
- 21. The process of claim 1, wherein the electrolysis is conducted with a current efficiency of greater than 90% at a concentration of sodium hydroxide of more than 20%.
- 22. 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, said membrane having an ion exchange capacity of sulfonic and carboxylic acid groups of from 0.5 to 4.0 milliequivalents per gram of dry resin, the ion exchange capacity of the carboxylic acid groups being from 0.05 to 1.5 milliequivalents per gram of dry resin.
- 23. The process of claim 22, wherein the electrolysis is conducted with a current efficiency of greater than 90% at a concentration of sodium hydroxide of more than 20%.
- 24. 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 4.0 milliequivalents per gram of dry resin, the ion exchange capacity of the carboxylic acid groups being from 0.05 to 1.5 milliequivalents per gram of dry resin.
- 25. The process of claim 24, wherein the aqueous sodium chloride solution charged into the anode chamber is purified by ion exchange.
- 26. The process of claim 24, wherein the membrane has an ion exchange capacity of sulfonic and carboxylic acid groups of from about 0.88 to about 2.21 milliequivalents per gram of dry resin.
- 27. A cation exchange membrane used in the electrolysis of an aqueous sodium chloride solution 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 4.0 milliequivalents per gram of dry resin, the ion exchange capacity of the carboxylic acid groups being from 0.05 to 1.5 milliequivalents per gram of dry resin.
- 28. A cation exchange membrane in accordance with claim 27, wherein a perfluorocarbon polymer having pendant carboxylic acid groups is present on the surface of the membrane.
- 29. A cation exchange membrane in accordance with claim 27, wherein a perfluorocarbon polymer having pendant carboxylic acid groups is present on one surface of the membrane.
- 30. A cation exchange membrane in accordance with claim 27, wherein a perfluorocarbon polymer having pendant carboxylic acid groups is present, together with a perfluorocarbon polymer having pendant sulfonic acid groups, on one surface of the membrane.
- 31. A cation exchange membrane in accordance with claim 30, wherein a perfluorocarbon polymer having pendant sulfonic acid groups is present on another surface of the membrane.
- 32. A cation exchange membrane in accordance with claim 27, which has a water content in the sodium salt form of from 5 to 50% by weight.
- 33. A cation exchange membrane in accordance with claim 27, which comprises a physical combination of perfluorocarbon polymer having pendant carboxylic acid groups with perfluorocarbon polymer having pendant sulfonic acid groups.
- 34. A cation exchange membrane in accordance with claim 27, which includes a fiber reinforcement.
- 35. A cation exchange membrane in accordance with claim 27, wherein said perfluorocarbon polymer is a copolymer of at least one of tetrafluoroethylene and CF.sub.2 .dbd.CF--O--R.sub.f wherein R.sub.f is a perfluorinated alkyl group containing 1 to 3 carbon atoms with perfluorocarbon vinyl monomers containing carboxylic acid groups and sulfonic acid groups or functional groups which can be converted to carboxylic acid or sulfonic acid groups.
- 36. A cation exchange membrane in accordance with claim 27, wherein said perfluorocarbon polymer is a copolymer of a perfluorocarbon vinyl monomer having the general formula:
- CF.sub.2 .dbd.CF--O--(CF.sub.2).sub.n --X
- wherein n is an integer of 2 to 12, and X is CN, COF, COOH, COOR, COOM or CONR.sub.2 R.sub.3, where R is an alkyl group containing 1 to 10 carbon atoms, R.sub.2 and R.sub.3 are individually hydrogen or an alkyl group containing 1 to 10 carbon atoms, and M is sodium, potassium or cesium; and a perfluorocarbon sulfonyl fluoride having the general formula:
- F--SO.sub.2 --CFR.sub.g --CF.sub.2 --O(CFYCF.sub.2 O).sub.m --CF.dbd.CF.sub.2
- wherein R.sub.g is fluorine or a perfluoroalkyl group having 1 to 10 carbon atoms, Y is fluorine or a trifluoromethyl group, and m is an integer of 1 to 3, with at least one of tetrafluoroethylene and CF.sub.2 .dbd.CF--O--R.sub.f wherein R.sub.f is a perfluorinated alkyl group containing 1 to 3 carbon atoms, which copolymer is hydrolyzed, if necessary, to form said acid groups.
- 37. A cation exchange membrane in accordance with claim 27, wherein said perfluorocarbon polymer is a copolymer of a perfluoroacrylic acid having the general formula:
- CF.sub.2 .dbd.CF--COZ
- wherein Z is fluorine, an alkoxy group containing 1 to 10 carbon atoms, amino or hydroxy; and a perfluorocarbon sulfonyl fluoride having the general formula:
- F--SO.sub.2 --CFR.sub.g --CF.sub.2 --O(CFYCF.sub.2 O).sub.m --CF.dbd.CF.sub.2
- wherein R.sub.g is fluorine or a perfluoroalkyl group having 1 to 10 carbon atoms, Y is fluorine or a trifluoromethyl group, and m is an integer of 1 to 3, with at least one of tetrafluoroethylene and CF.sub.2 .dbd.CF--O--R.sub.f wherein R.sub.f is a perfluorinated alkyl group containing 1 to 3 carbon atoms, which copolymer is hydrolyzed, if necessary, to form said acid groups.
- 38. A cation exchange membrane in accordance with claim 27, wherein said cation exchange membrane is prepared by impregnating or coating a membrane of a copolymer of (A) a perfluorovinyl ether having the general formula:
- LSO.sub.2 CFR.sub.g CF.sub.2 O(CFYCF.sub.2 O).sub.m --CF.dbd.CF.sub.2
- wherein L is hydroxy, fluorine or OA, where A is a quaternary ammonium radical; R.sub.g is fluorine or a perfluoroalkyl group having 1 to 10 carbon atoms; Y is fluorine or a trifluoromethyl group; and m is an integer of 1 to 3, and (B) at least one of tetrafluoroethylene and CF.sub.2 .dbd.CFOR.sub.f wherein R.sub.f is a perfluorinated alkyl group containing 1 to 3 carbon atoms, with a perfluorovinyl compound having pendant carboxylic acid groups or derivatives thereof, polymerizing said impregnated or coated vinyl compound, and hydrolyzing, if necessary, to form said acid groups.
- 39. A cation exchange membrane in accordance with claim 38, wherein said perfluorovinyl compound is at least one member selected from the group consisting of compounds having the formula:
- CF.sub.2 .dbd.CF--O--(CF.sub.2).sub.n --X
- wherein n is an integer of 2 to 12, and X is CN, COF, COOH, COOR, COOM or CONR.sub.2 R.sub.3, where R is an alkyl group containing 1 to 10 carbon atoms, R.sub.2 and R.sub.3 are individually hydrogen or an alkyl group containing 1 to 10 carbon atoms, and M is sodium, potassium or cesium, and compounds having the formula:
- CF.sub.2 .dbd.CF--COZ
- wherein Z is fluorine or an alkoxy group containing 1 to 10 carbon atoms.
- 40. A cation exchange membrane in accordance with claim 27, wherein said cation exchange membrane is prepared by impregnating or coating a membrane of a copolymer of (A) a perfluorovinyl ether having the general formula:
- LSO.sub.2 CFR.sub.g CF.sub.2 O(CFYCF.sub.2 O).sub.m --CF.dbd.CF.sub.2
- wherein L is hydroxy, fluorine or OA, where A is a quaternary ammonium radical; R.sub.g is fluorine or a perfluoroalkyl group having 1 to 10 carbon atoms; Y is fluorine or a trifluoromethyl group; and m is an integer of 1 to 3, and (B) at least one of tetrafluoroethylene and CF.sub.2 .dbd.CFOR.sub.f wherein R.sub.f is a perfluorinated alkyl group containing 1 to 3 carbon atoms, with a solution of a perfluorocarbon polymer having pendant carboxylic acid groups or derivatives thereof, and hydrolyzing, if necessary, to form said acid groups.
- 41. A cation exchange membrane in accordance with claim 38, 39 or 40, wherein the impregnating or coating is conducted on one surface of the membrane.
- 42. A cation exchange membrane in accordance with claim 27, wherein the thickness of the membrane is 0.05 to 1.5 mm.
- 43. A cation exchange membrane in accordance with claim 27, wherein the ion exchange capacity of sulfonic and carboxylic acid groups is from about 0.88 to about 2.21 milliequivalents per gram of dry resin.
- 44. A cation exchange membrane used in the electrolysis of an aqueous sodium chloride solution 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 4.0 milliequivalents per gram of dry resin, the ion exchange capacity of the carboxylic acid groups being from 0.05 to 1.5 milliequivalents per gram of dry resin, said membrane providing high current efficiency at high concentrations of sodium hydroxide.
- 45. A cation exchange membrane in accordance with claim 44, wherein said membrane is capable of providing a current efficiency of greater than 90% at a concentration of sodium hydroxide of more than 20%.
- 46. An electrolytic cell comprising an anode chamber and a cathode chamber separated by a cation exchange membrane which is used for the production of aqueous sodium hydroxide in the cathode chamber by electrolysis 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 4.0 milliequivalents per gram of dry resin, the ion exchange capacity of the carboxylic acid groups being from 0.05 to 1.5 milliequivalents per gram of dry resin.
- 47. An electrolytic cell in accordance with claim 46, wherein a perfluorocarbon polymer having pendant carboxylic acid groups is present on the surface of the membrane.
- 48. An electrolytic cell in accordance with claim 46, wherein a perfluorocarbon polymer having pendant carboxylic acid groups is present on one surface of the membrane.
- 49. An electrolytic cell in accordance with claim 46, wherein a perfluorocarbon polymer having pendant carboxylic acid groups is present, together with a perfluorocarbon polymer having pendant sulfonic acid groups, on one surface of the membrane.
- 50. An electrolytic cell in accordance with claim 49, wherein a perfluorocarbon polymer having pendant sulfonic acid groups is present on another surface of the membrane.
- 51. An electrolytic cell in accordance with claim 46, wherein the membrane in the sodium salt form has a water content of from 5 to 50% by weight.
- 52. An electrolytic cell in accordance with claim 46, wherein the membrane comprises a physical combination of perfluorocarbon polymer having pendant carboxylic acid groups with perfluorocarbon polymer having pendant sulfonic acid groups.
- 53. An electrolytic cell in accordance with claim 46, wherein the cation exchange membrane is fiber reinforced.
- 54. An electrolytic cell in accordance with claim 46, wherein said perfluorocarbon polymer is a copolymer of at least one of tetrafluoroethylene and CF.sub.2 .dbd.CF--O--R.sub.f wherein R.sub.f is a perfluorinated alkyl group containing 1 to 3 carbon atoms with perfluorocarbon vinyl monomers containing carboxylic acid groups and sulfonic acid groups or functional groups which can be converted to carboxylic acid or sulfonic acid groups.
- 55. An electrolytic cell in accordance with claim 46, wherein said perfluorocarbon polymer is a copolymer of a perfluorocarbon vinyl monomer having the general formula:
- CF.sub.2 .dbd.CF--O--(CF.sub.2).sub.n --X
- wherein n is an integer of 2 to 12, and X is CN, COF, COOH, COOR, COOM or CONR.sub.2 R.sub.3 where R is an alkyl group containing 1 to 10 carbon atoms, R.sub.2 and R.sub.3 are individually hydrogen or an alkyl group containing 1 to 10 carbon atoms, and M is sodium, potassium or cesium; and a perfluorocarbon sulfonyl fluoride having the general formula:
- F--SO.sub.2 --CFR.sub.g --CF.sub.2 --O(CFYCF.sub.2 O).sub.m --CF.dbd.CF.sub.2
- wherein R.sub.g is fluorine or a perfluoroalkyl group having 1 to 10 carbon atoms, Y is fluorine or a trifluoromethyl group, and m is an integer of 1 to 3, with at least one of tetrafluoroethylene and CF.sub.2 .dbd.CF--O--R.sub.f wherein R.sub.f is a perfluorinated alkyl group containing 1 to 3 carbon atoms, which copolymer is hydrolyzed, if necessary, to form said acid groups.
- 56. An electrolytic cell in accordance with claim 46, wherein said perfluorocarbon polymer is a copolymer of a perfluoroacrylic acid having the general formula:
- CF.sub.2 .dbd.CF--COZ
- wherein Z is fluorine, an alkoxy group containing 1 to 10 carbon atoms, amino or hydroxy; and a perfluorocarbon sulfonyl fluoride having the general formula:
- F--SO.sub.2 --CFR.sub.g --CF.sub.2 --O(CFYCF.sub.2 O).sub.m --CF.dbd.CF.sub.2
- wherein R.sub.g is fluorine or a perfluoroalkyl group having 1 to 10 carbon atoms, Y is fluorine or a trifluoromethyl group, and m is an integer of 1 to 3, with at least one of tetrafluoroethylene and CF.sub.2 .dbd.CF--O--R.sub.f wherein R.sub.f is a perfluorinated alkyl group containing 1 to 3 carbon atoms, and hydrolyzing, if necessary, to form said acid groups.
- 57. An electrolytic cell in accordance with claim 46, wherein said cation exchange membrane is prepared by impregnating or coating a membrane of a copolymer of (A) a perfluorovinyl ether having the general formula:
- LSO.sub.2 CFR.sub.g CF.sub.2 O(CFYCF.sub.2 O).sub.m --CF.dbd.CF.sub.2
- wherein L is hydroxy, fluorine or OA, where A is a quaternary ammonium radical; R.sub.g is fluorine or a perfluoroalkyl group having 1 to 10 carbon atoms; Y is fluorine or a trifluoromethyl group; and m is an integer of 1 to 3, and (B) at least one of tetrafluoroethylene and CF.sub.2 .dbd.CFOR.sub.f wherein R.sub.f is a perfluorinated alkyl group containing 1 to 3 carbon atoms, with a perfluorovinyl compound having pendant carboxylic acid groups or derivatives thereof, polymerizing said impregnated or coated vinyl compound, and hydrolyzing, if necessary, to form said acid groups.
- 58. An electrolytic cell in accordance with claim 57, wherein said perfluorovinyl compound is at least one member selected from the group consisting of compounds having the formula:
- CF.sub.2 .dbd.CF--O--(CF.sub.2).sub.n --X
- wherein n is an integer of 2 to 12, and X is CN, COF, COOH, COOR, COOM or CONR.sub.2 R.sub.3, where R is an alkyl group containing 1 to 10 carbon atoms, R.sub.2 and R.sub.3 are individually hydrogen or an alkyl group containing 1 to 10 carbon atoms, and M is sodium, potassium or cesium, and compounds having the formula:
- CF.sub.2 .dbd.CF--COZ
- wherein Z is fluorine or an alkoxy group containing 1 to 10 carbon atoms.
- 59. An electrolytic cell in accordance with claim 46, wherein said cation exchange membrane is prepared by impregnating or coating a membrane of a copolymer of (A) a perfluorovinyl ether having the general formula:
- LSO.sub.2 CFR.sub.g CF.sub.2 O(CFYCF.sub.2 O).sub.m --CF.dbd.CF.sub.2
- wherein L is hydroxy, fluorine or OA, where A is a quaternary ammonium radical; R.sub.g is fluorine or a perfluoroalkyl group having 1 to 10 carbon atoms; Y is fluorine or a trifluoromethyl group; and m is an integer of 1 to 3, and (B) at least one of tetrafluoroethylene and CF.sub.2 .dbd.CFOR.sub.f wherein R.sub.f is a perfluorinated alkyl group containing 1 to 3 carbon atoms, with a solution of a perfluorocarbon polymer having pendant carboxylic acid groups or derivatives thereof, and hydrolyzing, if necessary, to form said acid groups.
- 60. An electrolytic cell in accordance with claim 57, 58 or 59, wherein the impregnating or coating is conducted on one surface of the membrane.
- 61. An electrolytic cell in accordance with claim 48, wherein said carboxylic acid groups are contained predominantly on said one surface of the membrane and wherein the membrane is disposed in said electrolytic cell such that said surface having the pendant carboxylic acid groups faces the cathode side of the cell.
- 62. An electrolytic cell in accordance with claim 46, wherein the thickness of the membrane is 0.05 to 1.5 mm.
- 63. An electrolytic cell in accordance with claim 46, wherein the membrane has an ion exchange capacity of sulfonic and carboxylic acid groups of from about 0.88 to about 2.21 milliequivalents per gram of dry resin.
- 64. An electrolytic cell comprising an anode chamber and a cathode chamber separated by a cation exchange membrane which is used for the production of aqueous sodium hydroxide in the cathode chamber by electrolysis 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 4.0 milliequivalents per gram of dry resin, the ion exchange capacity of the carboxylic acid groups being from 0.05 to 1.5 milliequivalents per gram of dry resin, said membrane providing high current efficiency at high concentrations of sodium hydroxide.
- 65. An electrolytic cell in accordance with claim 64, wherein said membrane is capable of providing a current efficiency of greater than 90% at a concentration of sodium hydroxide of more than 20%.
Priority Claims (1)
Number |
Date |
Country |
Kind |
49-25718 |
Mar 1974 |
JPX |
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RELATED APPLICATIONS
This application is a divisional of copending application Ser. No. 836,417, filed on Sept. 26, 1977, now abandoned, which is a continuation-in-part of application Ser. No. 745,196, filed on Nov. 26, 1976, now abandoned, which is, in turn, a continuation of application Ser. No. 556,288, filed on Mar. 7, 1975, now abandoned. Application Ser. No. 959,312, a divisional of said application Ser. No. 836,417, issued as U.S. Pat. No. 4,178,218 on Dec. 11, 1979. This case is also related to application Ser. No. 214,876, filed on Dec. 10, 1980, (now U.S. Pat. No. 4,357,218) a divisional of Ser. No. 836,417.
US Referenced Citations (7)
Divisions (1)
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836417 |
Sep 1977 |
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Continuations (1)
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Number |
Date |
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556288 |
Mar 1975 |
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Continuation in Parts (1)
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745196 |
Nov 1976 |
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