US5084149A
Expired / Lapsed
US
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Electrolytic process for producing chlorine dioxide
Assignee: Olin Corp
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Filing: 1991-04-04
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Granted: 1992-01-28
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Expires: 2011-04-04
Abstract
Abstract An electrochemical process and electrolytic cell for manufacturing chlorine-free chlorine dioxide from a dilute alkali metal chlorite solution in a single step is disclosed. The electrolytic cell uses a porous flow-through anode and a cathode separated by a suitable separator. The alkali metal chlorite solution has a conductive salt additive.
Inventors
- 👤 Jerry J. Kaczur
- 👤 David W. Cawlfield
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 16:03
CPC Classifications
C; C25; C25B; C25B1/00; C25B1/01; C25B1/24; C25B1/26; C25B9/00; C25B9/13; C25B9/15; C25B9/17; C25B9/19; C25B9/70; C25B9/73; C25B9/75; C25B9/77
Claims Analysis
Total Claims: 28
Claim 1
Independent Claim
176 words
A continuous electrochemical process for producing chlorine dioxide solution from an aqueous alkali metal chlorite solution in an electrolytic cell having an aqueous catholyte solution in a catholyte compartment, an anolyte in an anolyte compartment, and a separator between the anolyte and catholyte compartments, comprising the steps of: (a) feeding an aqueous alkali metal chlorite solution having a conductive salt additive into the anolyte compartment of the electrolytic cell to form the anolyte; (b) feeding an aqueous solution into the catholyte compartment of the cell to form the aqueous catholyte solution; (c) electrolyzing the anolyte by directing the anolyte in a single pass through a porous, high surface area anode to oxidize chlorite ions on the high surface area anode having a surface area to volume ratio of at least about 50 cm 2 /cm 3 to produce a substantially chlorine-free solution of chlorine dioxide in the anolyte compartment and to cause the alkali metal ions to pass through the separator into the catholyte compartment; and (d) removing the chlorine dioxide solution from the anolyte compartment.
Claim 2
Dependent Claim
176 words
A continuous electrochemical process for producing chlorine dioxide solution from an aqueous alkali metal chlorite solution in an electrolytic cell having an aqueous catholyte solution in a catholyte compartment, an anolyte in an anolyte compartment, and a separator between the anolyte and catholyte compartments, comprising the steps of: (a) feeding an aqueous alkali metal chlorite solution having a conductive salt additive into the anolyte compartment of the electrolytic cell to form the anolyte; (b) feeding an aqueous solution into the catholyte compartment of the cell to form the aqueous catholyte solution; (c) electrolyzing the anolyte by directing the anolyte in a single pass through a porous, high surface area anode to oxidize chlorite ions on the high surface area anode having a surface area to volume ratio of at least about 50 cm 2 /cm 3 to produce a substantially chlorine-free solution of chlorine dioxide in the anolyte compartment and to cause the alkali metal ions to pass through the separator into the catholyte compartment; and (d) removing the chlorine dioxide solution from the anolyte compartment.
Claim 3
Dependent Claim
40 words
The process according to claim 1 wherein the conductive salt additive is selected from the group of alkali metal salts consisting of acetates, benzoates, borates, bromides, carbonates, citrates, chlorides, formates, gluconates, lactates, nitrates, oxalates, phthalates, phosphates, salicylates, sulfates and tartrates.
Claim 4
Dependent Claim
18 words
The process according to claim 2 wherein sodium chloride is present in the aqueous alkali metal chlorite solution.
Claim 5
Dependent Claim
33 words
The process according to claim 2 wherein the ratio of the concentration of the conductive salt additive to the chlorite in the chlorite solution is from about 0.1 to about 100 to 1.
Claim 6
Dependent Claim
15 words
The process according to claim 4 further comprising using sodium chlorite as the chlorite solution.
Claim 7
Dependent Claim
33 words
The process according to claim 2 wherein the ratio of the concentration of the conductive salt additive to the chlorite in the chlorite solution is from about 0.2 to about 20 to 1.
Claim 8
Dependent Claim
33 words
The process according to claim 2 wherein the ratio of the concentration of the conductive salt additive to the chlorite in the chlorite solution is from about 0.5 to about 10 to 1.
Claim 9
Dependent Claim
27 words
The process according to claim 1 further comprising maintaining the concentration of the aqueous alkali metal chlorite solution between about 0.1 to about 30 grams per liter.
Claim 10
Dependent Claim
32 words
The process according to claim 1 further comprising maintaining the temperature of the anolyte and the aqueous catholyte solution during cell operation between about 5 degrees centigrade to about 50 degrees centigrade.
Claim 11
Dependent Claim
26 words
The process according to claim 1 further comprising operating the cell with a current density of between about 0.1 to about 10 kiloamperes per square meter.
Claim 12
Dependent Claim
25 words
The process according to claim 1 further comprising maintaining the residence time of anolyte in the cell from between about 0.1 to about 10 minutes.
Claim 13
Dependent Claim
25 words
The process according to claim 11 further comprising using a porous high surface area anode having a void fraction of greater than about 40 percent.
Claim 14
Dependent Claim
23 words
The process according to claim 12 further comprising operating the cell with an operating voltage of between about 2.0 and about 5.0 volts.
Claim 15
Dependent Claim
18 words
The process according to claim 1 further comprising using a cation permselective ion exchange membrane as the separator.
Claim 16
Dependent Claim
20 words
The process according to claim 1 further comprising using a dilute alkali metal hydroxide solution as the aqueous catholyte solution.
Claim 17
Dependent Claim
25 words
The process according to claim 15 further comprising electrolyzing the aqueous catholyte solution to produce gaseous hydrogen and alkali metal hydroxide in the catholyte compartment.
Claim 18
Dependent Claim
20 words
The process according to claim 16 further comprising removing the gaseous hydrogen and alkali metal hydroxide from the catholyte compartment.
Claim 19
Dependent Claim
16 words
The process according to claim 17 further comprising using sodium or potassium as the alkali metal.
Claim 20
Dependent Claim
22 words
The process according to claim 1 further comprising operating the cell with an anolyte pH of between about 2.0 to about 10.0.
Claim 21
Dependent Claim
22 words
The process according to claim 1 further comprising operating the cell at a pressure of between about 1.2 and about 5 atmospheres.
Claim 22
Dependent Claim
17 words
The process according to claim 1 further comprising operating the cell with water s the aqueous solution.
Claim 23
Dependent Claim
104 words
In a continuous electrochemical process for producing a chlorine-free chlorine dioxide solution from an aqueous alkali metal chlorite anolyte solution in an electrolytic cell having an aqueous catholyte solution and a separator between anolyte and catholyte compartments, the aqueous alkali metal chlorite solution anolyte solution being electrolyzed in a single pass through a porous, high surface area anode having a surface area to volume ratio of at least about 50 cm 2 /cm 3 to produce the chlorine-free chlorine dioxide solution that is removed from the anolyte compartment, the improvement comprising using a conductive salt additive in the aqueous alkali metal chlorite anolyte solution.
Claim 24
Dependent Claim
104 words
In a continuous electrochemical process for producing a chlorine-free chlorine dioxide solution from an aqueous alkali metal chlorite anolyte solution in an electrolytic cell having an aqueous catholyte solution and a separator between anolyte and catholyte compartments, the aqueous alkali metal chlorite solution anolyte solution being electrolyzed in a single pass through a porous, high surface area anode having a surface area to volume ratio of at least about 50 cm 2 /cm 3 to produce the chlorine-free chlorine dioxide solution that is removed from the anolyte compartment, the improvement comprising using a conductive salt additive in the aqueous alkali metal chlorite anolyte solution.
Claim 25
Dependent Claim
19 words
The process according to claim 22 further comprising operating the cell with a cation permselective membrane as the separator.
Claim 26
Dependent Claim
36 words
The process according to claim 22 wherein the conductive salt additive is selected from the group consisting of acetates, benzoates, borates, bromides, carbonates, citrates, chlorides, formates, gluconates, lactates, nitrates, oxalates, phthalates, phosphates, salicylates, sulfates and tartrates.
Claim 27
Dependent Claim
18 words
The process according to claim 22 wherein sodium chloride is present in the aqueous alkali metal chlorite solution.
Claim 28
Dependent Claim
19 words
The process according to claim 22 further comprising using sodium chlorite as the aqueous alkali metal chlorite anolyte solution.
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| 3.5 Years (Year 4) | 1995-01-27 | 1995-07-29 | 1996-01-28 | $2000.00 | Window Closed / Lapsed |
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