US3976549A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electrolysis method
Assignee: Oxytech Systems Inc
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Filing: 1973-02-26
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Granted: 1976-08-24
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Expires: 1993-02-26
Abstract
Abstract An improved method and apparatus for the electrolysis of ionizable chemical compounds is disclosed including specifically a process for the production of chlorine and caustic soda containing low concentrations of sodium chloride by the electrolysis of brine which comprises electrolyzing brine solutions in a two compartment cell equipped with a cathode and an anode separated by permselective barrier formed by sandwiching together two or more membranes consisting essentially of a hydrolyzed copolymer of tetrafluoroethylene and a sulfonated perfluorovinyl ether having the formula FSO2CF2CF2OCF(CF3)CF2OCF=CF2 said copolymer having an equivalent weight of from about 900 to about 1600. By the use of a multilayer membrane sandwich as the barrier the caustic current efficiency of the process is increased over that obtained when a single layer membrane is used as the barrier separating the cathode and anode.
Inventors
- 👤 Ralph Falvo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 05:18
CPC Classifications
C; C08; C08J; C08J5/00; C08J5/20; C08J5/22; C08J5/2206; C08J5/2218; C08J5/2231; C08J5/2237; C25; C25B; C25B1/00; C25B1/01; C25B1/34; C25B1/46; C08J2327/00; C08J2327/02; C08J2327/12; C08J2327/18
Claims Analysis
Total Claims: 29
Claim 1
Independent Claim
98 words
A process for the electrolytic decomposition of aqueous solutions of ionizable chemical compounds which comprises electrolyzing an aqueous solution of an ionizable chemical compound in an electrolytic cell having an anode compartment and a cathode compartment separated by a unitary barrier having at least two layers of a permselective membrane material which is impervious to liquids and gases and is a copolymer of tetrafluoroethylene and a sulfonated perfluorovinyl ether of the formula FSO 2 CF 2 CF 2 OCF (CF 3 ) CF 2 OCF=CF 2 said copolymer having an equivalent weight of from about 900 to 1600.
Claim 2
Dependent Claim
98 words
A process for the electrolytic decomposition of aqueous solutions of ionizable chemical compounds which comprises electrolyzing an aqueous solution of an ionizable chemical compound in an electrolytic cell having an anode compartment and a cathode compartment separated by a unitary barrier having at least two layers of a permselective membrane material which is impervious to liquids and gases and is a copolymer of tetrafluoroethylene and a sulfonated perfluorovinyl ether of the formula FSO 2 CF 2 CF 2 OCF (CF 3 ) CF 2 OCF=CF 2 said copolymer having an equivalent weight of from about 900 to 1600.
Claim 3
Dependent Claim
13 words
The process of claim 1 wherein said anode compartment contains a metallic anode.
Claim 4
Dependent Claim
27 words
The process of claim 2 wherein said metallic anode consists essentially of a valve metal having thereon a coating comprising a noble metal or an oxide thereof.
Claim 5
Dependent Claim
11 words
The process of claim 3 wherein said valve metal is titanium.
Claim 6
Dependent Claim
19 words
The process of claim 4 wherein said titanium is coated with a mixture of ruthenium oxide and titanium oxide.
Claim 7
Dependent Claim
26 words
The process of claim 1 wherein said barrier consists essentially of a sandwich of at least two layers of said co-polymer separated by a porous membrane.
Claim 8
Dependent Claim
14 words
The process of claim 6 wherein said porous membrane is composed of asbestos sheet.
Claim 9
Dependent Claim
26 words
The process of claim 7 wherein said barrier consists of a sandwich of two layers of said co-polymer separated by a porous membrane of asbestos sheet.
Claim 10
Dependent Claim
21 words
A process as claimed in claim 1 wherein the said copolymer has an equivalent weight of from about 1100 to 1400.
Claim 11
Dependent Claim
16 words
The process of claim 1 wherein said barrier consists of two layers of said membrane material.
Claim 12
Dependent Claim
82 words
A process for the production of chlorine and caustic containing low concentration of sodium chloride which comprises electrolyzing aqueous brine solutions in a cell equipped with an anode and a cathode separated by a unitary permselective barrier having at least two layers of a hydrolyzed copolymer of tetrafluoroethylene and a sulfonated perfluorovinyl ether of the formula FSO 2 CF 2 CF 2 OCF (CF 3 ) CF 2 OCF=CF 2 said copolymer having an equivalent weight of from about 900 to 1600.
Claim 13
Dependent Claim
82 words
A process for the production of chlorine and caustic containing low concentration of sodium chloride which comprises electrolyzing aqueous brine solutions in a cell equipped with an anode and a cathode separated by a unitary permselective barrier having at least two layers of a hydrolyzed copolymer of tetrafluoroethylene and a sulfonated perfluorovinyl ether of the formula FSO 2 CF 2 CF 2 OCF (CF 3 ) CF 2 OCF=CF 2 said copolymer having an equivalent weight of from about 900 to 1600.
Claim 14
Dependent Claim
20 words
A process as claimed in claim 11 wherein said copolymer has an equivalent weight of from about 1100 to 1400.
Claim 15
Dependent Claim
37 words
A process as claimed in claim 12 wherein said hydrolyzed copolymer is obtained by treating a copolymer containing sulfonyl fluoride groups with a member of the group selected from boiling water and hot dilute aqueous caustic alkali.
Claim 16
Dependent Claim
29 words
A process as claimed in claim 13 wherein the copolymer containing sulfonyl fluoride groups is treated with boiling water to hydrolyze the sulfonyl fluoride groups to sodium sulfonate groups.
Claim 17
Independent Claim
148 words
A method of electrolytically decomposing ionizable chemical compounds which comprises introducing an aqueous solution of said ionizable chemical compound into an electrolytic cell having an anode compartment and a cathode compartment, said compartments being separated by a unitary barrier having at least two layers of a homogeneous cation active membrane formed from hydrolyzed copolymer of tetrafluoroethylene and a sulfonated perfluorovinyl ether of the formula FSO 2 CF 2 CF 2 OCF (CF 3 ) CF 2 OCF=CF 2 said copolymer having an equivalent weight of from about 900 to 1600, impressing a decomposition voltage of from about 2.3 volts to 5 volts across the electrodes disposed in each of said compartments while maintaining an anode current density of from about 0.5 to 4 amperes per square inch and recovering from said cathode compartment a product containing less than about one percent by weight of said ionizable chemical compound.
Claim 18
Independent Claim
148 words
A method of electrolytically decomposing ionizable chemical compounds which comprises introducing an aqueous solution of said ionizable chemical compound into an electrolytic cell having an anode compartment and a cathode compartment, said compartments being separated by a unitary barrier having at least two layers of a homogeneous cation active membrane formed from hydrolyzed copolymer of tetrafluoroethylene and a sulfonated perfluorovinyl ether of the formula FSO 2 CF 2 CF 2 OCF (CF 3 ) CF 2 OCF=CF 2 said copolymer having an equivalent weight of from about 900 to 1600, impressing a decomposition voltage of from about 2.3 volts to 5 volts across the electrodes disposed in each of said compartments while maintaining an anode current density of from about 0.5 to 4 amperes per square inch and recovering from said cathode compartment a product containing less than about one percent by weight of said ionizable chemical compound.
Claim 19
Dependent Claim
39 words
The method as described in claim 15 wherein said ionizable chemical compound is an alkali metal chloride and the product recovered from said cathode compartment is an alkali metal hydroxide containing less than one percent of alkali metal chloride.
Claim 20
Dependent Claim
15 words
The method as described in claim 16 wherein the alkali metal chloride is sodium chloride.
Claim 21
Dependent Claim
39 words
The method as described in claim 17 wherein the sodium chloride solution contains from about 200 gpl to 320 gpl sodium chloride and the sodium hydroxide concentration in the cathode compartment is maintained above about 10 percent by weight.
Claim 22
Dependent Claim
28 words
The method as described in claim 11 wherein the sodium hydroxide concentration in the cathode compartment is maintained from about 24 percent to about 38 percent by weight.
Claim 23
Dependent Claim
22 words
The method as described in claim 17 wherein the sodium chloride solution has a pH of from about 1 to about 5.
Claim 24
Dependent Claim
21 words
The method as described in claim 20 wherein the sodium chloride solution has a pH of from about 3.0 to 4.5.
Claim 25
Dependent Claim
17 words
The process of claim 15 wherein said barrier consists of two layers of said cation active membrane.
Claim 26
Dependent Claim
104 words
A process for the electrolytic decomposition of aqueous solutions of ionizable chemical compounds which comprises electrolyzing an aqueous solution of an ionizable chemical compound in an electrolytic cell having at least one bipolar electrode, an anode compartment and a cathode compartment, said compartments being separated by a unitary barrier having two layers of a permselective membrane material which is impervious to liquids and gases and is a copolymer of tetrafluoroethylene and a sulfonated perfluorovinyl ether of the formula FSO 2 CF 2 CF 2 OCF (CF 3 ) CF 2 OCF=CF 2 said copolymer having an equivalent weight of from about 900 to 1600.
Claim 27
Dependent Claim
104 words
A process for the electrolytic decomposition of aqueous solutions of ionizable chemical compounds which comprises electrolyzing an aqueous solution of an ionizable chemical compound in an electrolytic cell having at least one bipolar electrode, an anode compartment and a cathode compartment, said compartments being separated by a unitary barrier having two layers of a permselective membrane material which is impervious to liquids and gases and is a copolymer of tetrafluoroethylene and a sulfonated perfluorovinyl ether of the formula FSO 2 CF 2 CF 2 OCF (CF 3 ) CF 2 OCF=CF 2 said copolymer having an equivalent weight of from about 900 to 1600.
Claim 28
Dependent Claim
43 words
The process of claim 23 wherein the cathode side of said bipolar electrode is formed of steel and the anode side of said bipolar electrode is formed of a valve metal having a coating thereon comprising a noble metal or noble metal oxide.
Claim 29
Dependent Claim
18 words
The process of claim 24 wherein said valve metal is titanium and the coating thereon comprises ruthenium oxide.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-08-24 | 1980-02-23 | 1980-08-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-08-24 | 1984-02-23 | 1984-08-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-08-24 | 1988-02-23 | 1988-08-24 | $7700.00 | Window Closed / Lapsed |