US4210501A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Generation of halogens by electrolysis of hydrogen halides in a cell having catalytic electrodes bonded to a solid polymer electrolyte
Assignee: De Nora SpA
•
Filing: 1978-07-06
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Granted: 1980-07-01
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Expires: 1998-07-06
Abstract
Abstract A halogen such as chlorine is produced by the electrolysis of an aqueous solution of a hydrogen halide such as hydrochloric acid in an electrolysis cell having anolyte and catholyte chambers separated by a solid polymer electrolyte in the form of a stable, selectively permeable, hydrated ion exchange membrane. Catalytic electrodes in the form of fluorocarbon bonded, thermally stabilized, reduced oxides of platinum group metals are bonded to at least one surface of the membrane and an aqueous hydrochloric acid solution is brought in contact with the bonded anode to generate chlorine at the anode and hydrogen at the cathode.
Inventors
- 👤 Russell M. Dempsey
- 👤 Thomas G. Coker
- 👤 Anthony B. La Conti
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 11:41
CPC Classifications
C; C25; C25B; C25B1/00; C25B1/01; C25B1/24; C25B1/26; C25B1/34; C25B1/46; C25B11/00; C25B11/04; C25B11/051; C25B11/073; C25B11/091; C25B11/095; C25B9/00; C25B9/17; C25B9/19; C25B9/23
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
196 words
A process for the continuous production of chlorine from hydrochloric acid which comprises: (a) continuously providing an aqueous solution of hydrochloric acid to the anode compartment of an electrolytic cell which is separated from the cathode compartment by a cation selective ion exchange membrane, bringing the solution into contact with a catalytic, bonded, graphite anode electrode activated with reduced platinum group metals and oxides thereof bonded to and embedded in the membrane on the side facing the anode compartment said anode being opposite to a catalytic cathode bonded to and embedded in the other side of the membrane forming a unitary electrode-membrane structure whereby catalytic sites in the electrodes are in contact with the ion exchanging sites of the membrane so that electrolysis takes place directly at the membrane-electrode interface, (b) applying a potential to the electrodes through separate electron conductive current collectors in physical contact with the bonded electromechanically active electrodes to electrolyze the aqueous hydrochloric acid solution to produce chlorine at the anode electrode and hydrogen ions which are transported across said membrane to produce hydrogen at the cathode electrode, (c) continuously removing chlorine from the anode compartment and hydrogen from the cathode department.
Claim 2
Dependent Claim
196 words
A process for the continuous production of chlorine from hydrochloric acid which comprises: (a) continuously providing an aqueous solution of hydrochloric acid to the anode compartment of an electrolytic cell which is separated from the cathode compartment by a cation selective ion exchange membrane, bringing the solution into contact with a catalytic, bonded, graphite anode electrode activated with reduced platinum group metals and oxides thereof bonded to and embedded in the membrane on the side facing the anode compartment said anode being opposite to a catalytic cathode bonded to and embedded in the other side of the membrane forming a unitary electrode-membrane structure whereby catalytic sites in the electrodes are in contact with the ion exchanging sites of the membrane so that electrolysis takes place directly at the membrane-electrode interface, (b) applying a potential to the electrodes through separate electron conductive current collectors in physical contact with the bonded electromechanically active electrodes to electrolyze the aqueous hydrochloric acid solution to produce chlorine at the anode electrode and hydrogen ions which are transported across said membrane to produce hydrogen at the cathode electrode, (c) continuously removing chlorine from the anode compartment and hydrogen from the cathode department.
Claim 3
Dependent Claim
33 words
The process of claim 1 wherein the aqueous hydrochloric acid solution is brought into contact with the electrode in which the reduced platinum group metal oxides are temperature stabilized, reduced oxides of ruthenium.
Claim 4
Dependent Claim
47 words
The process of claim 2 wherein the aqueous hydrochloric acid solution is brought into contact with the electrode which is further stabilized and includes reduced metallic oxides chosen from the group consisting of the reduced oxides of iridium, tantalum, titanium, and niobium to form a binary system.
Claim 5
Dependent Claim
30 words
The process of claim 3 wherein the aqueous hydrochloric acid solution is brought into contact with the electrode which is further stabilized by the inclusion of reduced oxides of iridium.
Claim 6
Dependent Claim
61 words
The process of claim 4 wherein the aqueous hydrochloric acid solution is brought into contact with the electrode and the reduced oxides of ruthenium and iridium are stabilized by the inclusion of reduced oxides chosen from the group consisting of the reduced oxides of titanium, the reduced oxides of niobium and the reduced oxides of tantalum to form a ternary system.
Claim 7
Dependent Claim
39 words
The process of claim 5 wherein the aqueous hydrochloric acid solution is brought into contact with the electrode which includes the reduced oxides of titanium to form the ternary system with the the reduced oxides of ruthenium and iridium.
Claim 8
Dependent Claim
89 words
A process for generating a halogen which comprises electrolyzing an aqueous solution of a hydrogen halide between a pair of electrodes separated by an ion permeable membrane, the improvement which comprises conducting the electrolysis with at least one of the electrodes including an electronconductive platinum group metal catalyst bonded to the membrane at a plurality of points forming a unitary electrode membrane structure exposed to an aqueous electrolyte wherein electrolysis of the aqueous solution is effected to keep oxygen evolution at the halogen evolving electrode below 5% by volume.
Claim 9
Dependent Claim
89 words
A process for generating a halogen which comprises electrolyzing an aqueous solution of a hydrogen halide between a pair of electrodes separated by an ion permeable membrane, the improvement which comprises conducting the electrolysis with at least one of the electrodes including an electronconductive platinum group metal catalyst bonded to the membrane at a plurality of points forming a unitary electrode membrane structure exposed to an aqueous electrolyte wherein electrolysis of the aqueous solution is effected to keep oxygen evolution at the halogen evolving electrode below 5% by volume.
Claim 10
Dependent Claim
19 words
The process according to claim 7 wherein the oxygen at the halogen evolving electrode is below 2% by volume.
Claim 11
Dependent Claim
27 words
The process according to claim 7 wherein the hydrogen halide concentration is maintained in excess of 7 N to maintain the oxygen concentration below 5% by volume.
Claim 12
Dependent Claim
27 words
The process according to claim 7 wherein the hydrogen halide concentration is maintained in the range 7-12 N to maintain the oxygen concentration below 2% by volume.
Claim 13
Dependent Claim
55 words
The process according to claim 7 wherein the ion permeable member is hydraulically impermeable and restrains flow of electrolyte from the anode side to the cathode side, and the plurality of electroconductive particles are bonded together by a fluorocarbon polymer to form a gas permeable layer bonded to one surface of the ion permeable membrane.
Claim 14
Dependent Claim
53 words
The process according to claim 4 wherein each of the electrodes comprises a thin layer of finely divided electroconductive catalytic particles bonded to opposite surfaces of the membrane to provide gas permeable anode and cathode electrodes whereby the catalytic sites in the electrodes are in contact with ion exchanging radicals in the membrane.
Claim 15
Dependent Claim
111 words
A process for generating a halogen which comprises electrolyzing an aqueous solution of a hydrogen halide between a pair of electrodes separated by an ion permeable membrane, the improvement which comprises conducting the electrolysis with at least one of the electrodes, including an electroconducting, thermally stabilized, reduced oxide of a platinum group metal bonded to the membrane at a plurality of points to form a unitary electrode-membrane structure, supplying potential to the electrodes by electron conductive current distributors the surface of which is in contact with the electrode and is exposed to the electrolyte, said electrodes having lower hydrogen or chlorine overvoltages than the electron current distributors in physical contact therewith.
Claim 16
Dependent Claim
111 words
A process for generating a halogen which comprises electrolyzing an aqueous solution of a hydrogen halide between a pair of electrodes separated by an ion permeable membrane, the improvement which comprises conducting the electrolysis with at least one of the electrodes, including an electroconducting, thermally stabilized, reduced oxide of a platinum group metal bonded to the membrane at a plurality of points to form a unitary electrode-membrane structure, supplying potential to the electrodes by electron conductive current distributors the surface of which is in contact with the electrode and is exposed to the electrolyte, said electrodes having lower hydrogen or chlorine overvoltages than the electron current distributors in physical contact therewith.
Claim 17
Dependent Claim
41 words
The process according to claim 13 wherein the other electrode includes electroconducting, catalytic particles bonded to the membrane at a plurality of points, said electrodes respectively having lower hydrogen and chlorine overvoltages than the electron current distributors in physical contact therewith.
Claim 18
Dependent Claim
34 words
The process according to claim 14 wherein the particles of the reduced oxides of ruthenium are activated by the inclusion of at least one thermally stabilized, reduced oxide of platinum group or transition metals.
Claim 19
Dependent Claim
41 words
The process according to claim 13 wherein each of the electrodes comprises a layer of electroconductive, thermally stabilized, reduced oxide particles of a platinum group metal bonded to opposite surfaces of the membrane to provide gas permeable anode and cathode electrodes.
Claim 20
Dependent Claim
30 words
The process according to claim 16 wherein the layers of particles forming include electroconductive graphite particles and particles of a material of the group consisting of electroconductive noble metal oxides.
Claim 21
Dependent Claim
23 words
The process according to claim 17 wherein the electroconductive graphite particles in the cathode and anode layers are activated by ruthenium oxide particles.
Claim 22
Dependent Claim
52 words
The process according to claim 18 wherein the electroconductive particles in each of the layers are activated by the inclusion of at least two kinds of particles of materials including noble metal oxides and transition metal oxides with at least one of the two kinds of particles being noble metal oxide particles.
Claim 23
Dependent Claim
48 words
The process according to claim 13 wherein the anode comprises a layer or particles of thermally stabilized, reduced oxides of a platinum group metal bonded to the membrane, and the electron conductive current distributor in contact with said anode has a higher chlorine overvoltage than the anode electrode.
Claim 24
Dependent Claim
39 words
The process according to claim 13 wherein the cathode includes a layer of electroconductive, catalytic particles bonded to the membrane and the electron conductive current distributor in physical contact therewith has a higher hydrogen overvoltage than said cathode electrode.
Claim 25
Dependent Claim
50 words
The process according to claim 13 wherein the anode and cathode electrodes are both bonded to the membrane and the electron conductive current distributors in contact with said anode and cathode electrodes have chlorine and hydrogen overvoltages which are higher than those of the bonded cathode and cathode electrodes respectively.
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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) | 1983-07-01 | 1983-12-31 | 1984-07-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-07-01 | 1987-12-31 | 1988-07-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-07-01 | 1991-12-31 | 1992-07-01 | $7700.00 | Window Closed / Lapsed |