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 a fluorocarbon polymer containing pendant carboxylic acid and sulfonic acid groups, the total ion exchange capacity of sulfonic and carboxylic acid groups being from 0.5 to 4.0 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.
- 2. The process of claim 1, wherein the ion exchange capacity of the carboxylic acid groups in said membrane is at least 0.005 milliequivalent per gram of dry resin.
- 3. The process of claim 1, wherein a fluorocarbon polymer containing pendant carboxylic acid groups is present on the surface of the membrane.
- 4. The process of claim 1, wherein a fluorocarbon polymer containing pendant carboxylic acid groups is present on one surface of the membrane.
- 5. The process of claim 1, wherein the membrane in the sodium salt form has a water content of from 5 to 50% by weight.
- 6. The process of claim 1, wherein said membrane comprises a combination of a fluorocarbon polymer having pendant carboxylic acid groups with a fluorocarbon polymer having pendant sulfonic acid groups.
- 7. The process of claim 1, wherein said fluorocarbon polymer comprises a perfluorocarbon polymer having carboxylic acid groups and 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 fluorocarbon polymer comprises 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 fluorocarbon 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 fluorocarbon polymer comprises a copolymer of a fluorocarbon vinyl monomer having the general formula:
- CF.sub.2 =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 fluorocarbon polymer comprises 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 comprising 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 trifluoroemethyl 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 vinyl compound having 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 vinyl 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 comprising 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 polymer having carboxylic acid groups or derivatives thereof, and hydrolyzing, if necessary, to form said acid groups.
- 15. A process according to claims 12, 13 or 14, wherein the impregnating or coating is conducted on one surface of the membrane.
- 16. The process of claim 15, 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 carboxylic acid groups faces the cathode side of the cell.
- 17. A process according to claims 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 aqueous sodium chloride solution charged to the anode compartment is purified with an ion exchange resin.
- 21. The process of claim 20, wherein the aqueous sodium chloride solution has a calcium content of less than 1 ppm.
- 22. A cation exchange membrane suitable for use in the electrolysis of an aqueous sodium chloride solution consisting essentially of a fluorocarbon polymer containing pendant carboxylic acid and sulfonic acid groups, the total ion exchange capacity of sulfonic and carboxylic acid groups being from 0.5 to 4.0 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.
- 23. A cation exchange membrane in accordance with claim 22, wherein the ion exchange capacity of the carboxylic acid groups in said membrane is at least 0.005 milliequivalent per gram of dry resin.
- 24. A cation exchange membrane in accordance with claim 22, wherein a fluorocarbon polymer containing pendant carboxylic acid groups is present on the surface of the membrane.
- 25. A cation exchange membrane in accordance with claim 22, wherein a fluorocarbon polymer containing pendant carboxylic acid groups is present on one surface of the membrane.
- 26. A cation exchange membrane in accordance with claim 22, which has a water content in the sodium salt form of from 5 to 50% by weight.
- 27. A cation exchange membrane in accordance with claim 22, which comprises a combination of a fluorocarbon polymer having pendant carboxylic acid groups with a fluorocarbon polymer having pendant sulfonic acid groups.
- 28. A cation exchange membrane in accordance with claim 22, wherein said fluorocarbon polymer comprises a perfluorocarbon polymer having carboxylic acid groups and sulfonic acid groups.
- 29. A cation exchange membrane in accordance with claim 22, which includes a fiber reinforcement.
- 30. A cation exchange membrane in accordance with claim 22, wherein said fluorocarbon polymer comprises 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 fluorocarbon vinyl monomers containing carboxylic acid groups and sulfonic acid groups or functional groups which can be converted to carboxylic acid or sulfonic acid groups.
- 31. A cation exchange membrane in accordance with claim 22, wherein said fluorocarbon polymer comprises a copolymer of a fluorocarbon 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.
- 32. A cation exchange membrane in accordance with claim 22, wherein said fluorocarbon polymer comprises 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.
- 33. A cation exchange membrane in accordance with claim 22, wherein said cation exchange membrane is prepared by impregnating or coating a membrane comprising 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 tetrafluoromethyl 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 vinyl compound having carboxylic acid groups or derivatives thereof, polymerizing said impregnated or coated vinyl compound, and hydrolyzing, if necessary, to form said acid groups.
- 34. A cation exchange membrane in accordance with claim 33, wherein said vinyl 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.
- 35. A cation exchange membrane in accordance with claim 22, wherein said cation exchange membrane is prepared by impregnating or coating a membrane comprising 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 polymer having carboxylic acid groups or derivatives thereof, and hydrolyzing, if necessary, to form said acid groups.
- 36. A cation exchange membrane in accordance with claims 33, 34 or 35, wherein the impregnating or coating is conducted on one surface of the membrane.
- 37. A cation exchange membrane in accordance with claim 22, wherein the thickness of the membrane is 0.05 to 1.5 mm.
- 38. 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 a fluorocarbon polymer containing pendant carboxylic acid and sulfonic acid groups, said membrane having a total ion exchange capacity of sulfonic and carboxylic acid groups of from 0.5 to 4.0 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.
- 39. An electrolytic cell in accordance with claim 38, wherein the ion exchange capacity of the carboxylic acid groups in said membrane is at least 0.005 milliequivalent per gram of dry resin.
- 40. An electrolytic cell in accordance with claim 38, wherein a fluorocarbon polymer containing pendant carboxylic acid groups is present on the surface of the membrane.
- 41. An electrolytic cell in accordance with claim 38, wherein a fluorocarbon polymer containing pendant carboxylic acid groups is present on one surface of the membrane.
- 42. An electrolytic cell in accordance with claim 38, wherein the membrane in the sodium salt form has a water content of from 5 to 50% by weight.
- 43. An electrolytic cell in accordance with claim 38, wherein the membrane comprises a combination of a fluorocarbon polymer having pendant carboxylic acid groups with a fluorocarbon polymer having pendant sulfonic acid groups.
- 44. An electrolytic cell in accordance with claim 38, wherein said fluorocarbon polymer comprises a perfluorocarbon polymer having carboxylic acid groups and sulfonic acid groups.
- 45. An electrolytic cell in accordance with claim 38, wherein the cation exchange membrane is fiber reinforced.
- 46. An electrolytic cell in accordance with claim 38, wherein said fluorocarbon polymer comprises 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 fluorocarbon vinyl monomers containing carboxylic acid groups and sulfonic acid groups or functional groups which can be converted to carboxylic acid or sulfonic acid groups.
- 47. An electrolytic cell in accordance with claim 38, wherein said fluorocarbon polymer comprises a copolymer of a fluorocarbon 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.
- 48. An electrolytic cell in accordance with claim 38, wherein said fluorocarbon polymer comprises 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.
- 49. An electrolytic cell in accordance with claim 38, wherein said cation exchange membrane is prepared by impregnating or coating a membrane comprising 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 vinyl compound having carboxylic acid groups or derivatives thereof, polymerizing said impregnated or coated vinyl compound, and hydrolyzing, if necessary, to form said acid groups.
- 50. An electrolytic cell in accordance with claim 49, wherein said vinyl 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.
- 51. An electrolytic cell in accordance with claim 38, wherein said cation exchange membrane is prepared by impregnating or coating a membrane comprising 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 polymer having carboxylic acid groups or derivatives thereof, and hydrolyzing, if necessary, to form said acid groups.
- 52. An electrolytic cell in accordance with claims 49, 50 or 51, wherein the impregnating or coating is conducted on one surface of the membrane.
- 53. An electrolytic cell in accordance with claim 38, 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 carboxylic acid groups faces the cathode side of the cell.
- 54. An electrolytic cell in accordance with claim 38, wherein the thickness of the membrane is 0.05 to 1.5 mm.
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, 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.
US Referenced Citations (7)
Divisions (1)
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Number |
Date |
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Parent |
836417 |
Sep 1977 |
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Continuations (1)
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Number |
Date |
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Parent |
556288 |
Mar 1975 |
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Continuation in Parts (1)
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Number |
Date |
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Parent |
745196 |
Nov 1976 |
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