US4357218A — Cation exchange membrane and use thereof in the e…

Claim 1

Independent Claim 91 words

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, 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.

Claim 2

Dependent Claim 91 words

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, 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.

Claim 3

Dependent Claim 28 words

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.

Claim 4

Dependent Claim 22 words

The process of claim 1, wherein the perfluorocarbon polymer having pendant carboxylic acid groups is present on the surface of the membrane.

Claim 5

Dependent Claim 22 words

The process of claim 1, wherein a perfluorocarbon polymer having pendant carboxylic acid groups is present on one surface of the membrane.

Claim 6

Dependent Claim 32 words

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.

Claim 7

Dependent Claim 22 words

The process of claim 5, wherein a perfluorocarbon polymer having pendant sulfonic acid groups is present on another surface of the membrane.

Claim 8

Dependent Claim 24 words

The process of claim 1, wherein the membrane in the sodium salt form has a water content of from 5 to 50% by weight.

Claim 9

Dependent Claim 28 words

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.

Claim 10

Dependent Claim 13 words

The process of claim 1, wherein the cation exchange membrane is fiber reinforced.

Claim 11

Dependent Claim 63 words

The process of claim 1, wherein said perfluorocarbon polymer is a copolymer of at least one of tetrafluoroethylene and CF 2 ═CF--O--R f wherein R 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.

Claim 12

Dependent Claim 165 words

The process of claim 1, wherein said perfluorocarbon polymer is a copolymer of a perfluorocarbon 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 2 R 3 where R is an alkyl group containing 1 to 10 carbon atoms, R 2 and R 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═CF.sub.2 wherein R 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 2 ═CF--O--R f wherein R f is a perfluorinated alkyl group containing 1 to 3 carbon atoms, which copolymer is hydrolyzed, if necessary, to form said acid groups.

Claim 13

Dependent Claim 119 words

The process of claim 1, wherein said perfluorocarbon polymer is a copolymer of a perfluoroacrylic acid having the general formula: CF.sub.2 ═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 --O(CFYCF.sub.2 O).sub.m --CF═CF.sub.2 wherein R 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 2 ═CF--O--R f wherein R f is a perfluorinated alkyl group containing 1 to 3 carbon atoms, which copolymer is hydrolyzed, if necessary, to form said acid groups.

Claim 14

Dependent Claim 134 words

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═CF.sub.2 wherein L is hydroxy, fluorine or OA, where A is a quaternary ammonium radical; R 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 2 ═CFOR f wherein R 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.

Claim 15

Dependent Claim 108 words

The process of claim 13, wherein said perfluorovinyl compound is at least one member selected from the group consisting of compounds having the 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 2 R 3 , where R is an alkyl group containing 1 to 10 carbon atoms, R 2 and R 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 ═CF--COZ wherein Z is fluorine or an alkoxy group containing 1 to 10 carbon atoms.

Claim 16

Dependent Claim 130 words

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═CF.sub.2 wherein L is hydroxy, fluorine or OA, where A is a quaternary ammonium radical; R 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 2 ═CFOR f wherein R 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.

Claim 17

Dependent Claim 22 words

A process according to claim 13, 14 or 15, wherein the impregnating or coating is conducted on one surface of the membrane.

Claim 18

Dependent Claim 47 words

The process of claim 4, 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.

Claim 19

Dependent Claim 20 words

A process according to claim 10, 11, 12, 13, 14 or 15, wherein the cation exchange membrane is fiber reinforced.

Claim 20

Dependent Claim 16 words

The process of claim 1, wherein the thickness of the membrane is 0.05 to 1.5 mm.

Claim 21

Dependent Claim 54 words

The process of claim 1, wherein the electrolysis is conducted at a temperature of 0° to 150° 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%.

Claim 22

Dependent Claim 32 words

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.

Claim 23

Dependent Claim 151 words

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° to 150° 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.

Claim 24

Dependent Claim 151 words

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° to 150° 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.

Claim 25

Dependent Claim 21 words

The process of claim 22, wherein the aqueous sodium chloride solution charged into the anode chamber is purified by ion exchange.

Claim 26

Dependent Claim 32 words

The process of claim 22, wherein the membrane has a ion exchange capacity of sulfonic and carboxylic acid groups of from about 0.88 to about 2.21 milliequivalents per gram of dry resin.

Claim 27

Dependent Claim 68 words

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.

Claim 28

Dependent Claim 68 words

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.

Claim 29

Dependent Claim 32 words

A cation exchange membrane in accordance with claim 25, wherein the ion exchange capacity of the carboxylic acid groups in said membrane is at least 0.005 milliequivalent per gram of dry resin.

Claim 30

Dependent Claim 26 words

A cation exchange membrane in accordance with claim 25, wherein a perfluorocarbon polymer having pendant carboxylic acid groups is present on the surface of the membrane.

Claim 31

Dependent Claim 26 words

A cation exchange membrane in accordance with claim 25, wherein a perfluorocarbon polymer having pendant carboxylic acid groups is present on one surface of the membrane.

Claim 32

Dependent Claim 36 words

A cation exchange membrane in accordance with claim 25, 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.

Claim 33

Dependent Claim 26 words

A cation exchange membrane in accordance with claim 29, wherein a perfluorocarbon polymer having pendant sulfonic acid groups is present on another surface of the membrane.

Claim 34

Dependent Claim 26 words

A cation exchange membrane in accordance with claim 25, which has a water content in the sodium salt form of from 5 to 50% by weight.

Claim 35

Dependent Claim 30 words

A cation exchange membrane in accordance with claim 25, which comprises a physical combination of perfluorocarbon polymer having pendant carboxylic acid groups with perfluorocarbon polymer having pendant sulfonic acid groups.

Claim 36

Dependent Claim 14 words

A cation exchange membrane in accordance with claim 25, which includes a fiber reinforcement.

Claim 37

Dependent Claim 67 words

A cation exchange membrane in accordance with claim 25, wherein said perfluorocarbon polymer is a copolymer of at least one of tetrafluoroethylene and CF 2 ═CF--O--R f wherein R 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.

Claim 38

Dependent Claim 170 words

A cation exchange membrane in accordance with claim 25, wherein said perfluorocarbon polymer is a copolymer of a perfluorocarbon 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 2 R 3 , where R is an alkyl group containing 1 to 10 carbon atoms, R 2 and R 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═CF.sub.2 wherein R 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 2 ═CF--O--R f wherein R f is a perfluorinated alkyl group containing 1 to 3 carbon atoms, which copolymer is hydrolyzed, if necessary, to form said acid groups.

Claim 39

Dependent Claim 123 words

A cation exchange membrane in accordance with claim 25, wherein said perfluorocarbon polymer is a copolymer of a perfluoroacrylic acid having the general formula: CF.sub.2 ═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═CF.sub.2 wherein R 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 tetrafluoroethylene and CF 2 ═CF--O--R f wherein R f is a perfluorinated alkyl group containing 1 to 3 carbon atoms, which copolymer is hydrolyzed, if necessary, to form said acid groups.

Claim 40

Dependent Claim 138 words

A cation exchange membrane in accordance with claim 25, 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═CF.sub.2 wherein L is hydroxy, fluorine or OA, where A is a quaternary ammonium radical; R 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 2 ═CFOR f wherein R 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.

Claim 41

Dependent Claim 112 words

A cation exchange membrane in accordance with claim 37, wherein said perfluorovinyl compound is at least one member selected from the group consisting of compounds having the 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 2 R 3 , where R is an alkyl group containing 1 to 10 carbon atoms, R 2 and R 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 ═CF--COZ wherein Z is fluorine or an alkoxy group containing 1 to 10 carbom atoms.

Claim 42

Dependent Claim 134 words

A cation exchange membrane in accordance with claim 25, 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═CF.sub.2 wherein L is hydroxy, fluorine or OA, where A is a quaternary ammonium radical; R 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 2 ═CFOR f wherein R 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.

Claim 43

Dependent Claim 25 words

A cation exchange membrane in accordance with claim 37, 38 or 39, wherein the impregnating or coating is conducted on one surface of the membrane.

Claim 44

Dependent Claim 20 words

A cation exchange membrane in accordance with claim 25, wherein the thickness of the membrane is 0.05 to 1.5 mm.

Claim 45

Dependent Claim 33 words

A cation exchange membrane in accordance with claim 25, 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.

Claim 46

Dependent Claim 101 words

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.

Claim 47

Dependent Claim 101 words

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.

Claim 48

Dependent Claim 31 words

An electrolytic cell in accordance with claim 43, wherein the ion exchange capacity of the carboxylic acid groups in said membrane is at least 0.005 milliequivalent per gram of dry resin.

Claim 49

Dependent Claim 25 words

An electrolytic cell in accordance with claim 43, wherein a perfluorocarbon polymer having pendant carboxylic acid groups is present on the surface of the membrane.

Claim 50

Dependent Claim 25 words

An electrolytic cell in accordance with claim 43, wherein a perfluorocarbon polymer having pendant carboxylic acid groups is present on one surface of the membrane.

Claim 51

Dependent Claim 35 words

An electrolytic cell in accordance with claim 43, 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.

Claim 52

Dependent Claim 25 words

An electrolytic cell in accordance with claim 47, wherein a perfluorocarbon polymer having pendant sulfonic acid groups is present on another surface of the membrane.

Claim 53

Dependent Claim 27 words

An electrolytic cell in accordance with claim 43, wherein the membrane in the sodium salt form has a water content of from 5 to 50% by weight.

Claim 54

Dependent Claim 31 words

An electrolytic cell in accordance with claim 43, wherein the membrane comprises a physical combination of perfluorocarbon polymer having pendant carboxylic acid groups with perfluorocarbon polymer having pendant sulfonic acid groups.

Claim 55

Dependent Claim 16 words

An electrolytic cell in accordance with claim 43, wherein the cation exchange membrane is fiber reinforced.

Claim 56

Dependent Claim 66 words

An electrolytic cell in accordance with claim 43, wherein said perfluorocarbon polymer is a copolymer of at least one of tetrafluoroethylene and CF 2 ═CF--O--R f wherein R 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.

Claim 57

Dependent Claim 167 words

An electrolytic cell in accordance with claim 43, wherein said perfluorocarbon polymer is a copolymer of perfluorocarbon 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 2 R 3 where R is an alkyl group containing 1 to 10 carbon atoms, R 2 and R 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═CF.sub.2 wherein R 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 2 ═CF--O--R f wherein R f is a perfluorinated alkyl group containing 1 to 3 carbon atoms, which copolymer is hydrolyzed, if necessary, to form said acid groups.

Claim 58

Dependent Claim 121 words

An electrolytic cell in accordance with claim 43, wherein said perfluorocarbon polymer is a copolymer of a perfluoroacrylic acid having the general formula: CF.sub.2 ═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═CF.sub.2 wherein R 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 2 ═CF--O--R f wherein R f is a perfluorinated alkyl group containing 1 to 3 carbon atoms, and hydrolyzing, if necessary, to form said acid groups.

Claim 59

Dependent Claim 137 words

An electrolytic cell in accordance with claim 43, 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═CF.sub.2 wherein L is hydroxy, fluorine or OA, where A is a quaternary ammonium radical; R 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 2 ═CFOR f wherein R 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.

Claim 60

Dependent Claim 111 words

An electrolytic cell in accordance with claim 55, wherein said perfluorovinyl compound is at least one member selected from the group consisting of compounds having the 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 2 R 3 , where R is an alkyl group containing 1 to 10 carbon atoms, R 2 and R 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 ═CF--COZ wherein Z is fluorine or an alkoxy group containing 1 to 10 carbon atoms.

Claim 61

Dependent Claim 133 words

An electrolytic cell in accordance with claim 43, 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═CF.sub.2 wherein L is hydroxy, fluorine or OA, where A is a quaternary ammonium radical; R 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 2 ═CFOR f wherein R 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.

Claim 62

Dependent Claim 24 words

An electrolytic cell in accordance with claim 55, 56 or 57, wherein the impregnating or coating is conducted on one surface of the membrane.

Claim 63

Dependent Claim 50 words

An electrolytic cell in accordance with claim 46, wherein said carboxylic acid groups are cotained 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.

Claim 64

Dependent Claim 19 words

An electrolytic cell in accordance with claim 43, wherein the thickness of the membrane is 0.05 to 1.5 mm.

Claim 65

Dependent Claim 35 words

An electrolytic cell in accordance with claim 43, 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.

Claim 66

Dependent Claim 28 words

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%.

Claim 67

Dependent Claim 82 words

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.

Claim 68

Dependent Claim 82 words

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.

Claim 69

Dependent Claim 28 words

The process of claim 63, wherein the electrolysis is conducted with a current efficiency of greater than 90% at a concentration of sodium hydroxide of more than 20%.

Claim 70

Dependent Claim 62 words

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.

Claim 71

Dependent Claim 62 words

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.

Claim 72

Dependent Claim 33 words

A cation exchange membrane in accordance with claim 65, wherein said membrane is capable of providing a current efficiency of greater than 90% at a concentration of sodium hydroxide of more than 20%.

Claim 73

Dependent Claim 95 words

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.

Claim 74

Dependent Claim 95 words

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.

Claim 75

Dependent Claim 32 words

An electrolytic cell in accordance with claim 67, wherein said membrane is capable of providing a current efficiency of greater than 90% at a concentration of sodium hydroxide of more than 20%.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1985-11-01	1986-05-03	1986-11-02	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1989-11-01	1990-05-03	1990-11-02	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1993-11-01	1994-05-03	1994-11-02	$7700.00	Window Closed / Lapsed

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

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