Patent US5041196A successfully refreshed from Google Patents.
US5041196A
Expired / Lapsed
US
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Electrochemical method for producing chlorine dioxide solutions
Assignee: Arch Chemicals Inc
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Filing: 1989-12-26
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Granted: 1991-08-20
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Expires: 2009-12-26
Abstract
Abstract An electrochemical process and electrolytic cell for manufacturing chlorine-free chlorine dioxide from dilute alkali metal chlorite solutions in a single step is disclosed. The electrolytic cell uses a porous flow-through anode and a cathode separated by a suitable separator.
Inventors
- 👤 David W. Cawlfield
- 👤 Jerry J. Kaczur
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 14:26
CPC Classifications
C; C25; C25B; C25B1/00; C25B1/01; C25B1/24; C25B1/26; C25B9/00; C25B9/17; C25B9/19
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
160 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 and a separator between the anolyte and catholyte compartments, comprising the steps of: (a) feeding an aqueous alkali metal chlorite solution 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 having a surface area to volume ratio of at least about 50 cm 2 /cm 3 to convert chlorite ions on the high surface area anode to produce a 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
160 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 and a separator between the anolyte and catholyte compartments, comprising the steps of: (a) feeding an aqueous alkali metal chlorite solution 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 having a surface area to volume ratio of at least about 50 cm 2 /cm 3 to convert chlorite ions on the high surface area anode to produce a 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
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 4
Dependent Claim
31 words
The process according to claim 1 further comprising maintaining the temperature of the anolyte and the catholyte during cell operation between about qb 5 degrees centigrade to about 50 degrees centigrade.
Claim 5
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 6
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 7
Dependent Claim
25 words
The process according to claim 1 further comprising using a porous high surface areas anode having a void fraction of greater than about 40 percent.
Claim 8
Dependent Claim
23 words
The process according to claim 6 further comprising operating the cell with an operating voltage of between about 2.0 to about 5.0 volts.
Claim 9
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 10
Dependent Claim
23 words
The process according to claim 8 further comprising electrolyzing the catholyte to produce gaseous hydrogen and alkali metal hydroxide in the catholyte compartment.
Claim 11
Dependent Claim
20 words
The process according to claim 9 further comprising removing the gaseous hydrogen and alkali metal hydroxide from the catholyte compartment.
Claim 12
Dependent Claim
16 words
The process according to claim 10 further comprising using sodium or potassium as the alkali metal.
Claim 13
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 14
Dependent Claim
22 words
The process according to claim 1 further comprising operating the cell at a pressure of between about 1.2 to about 5 atmospheres.
Claim 15
Dependent Claim
19 words
The process according to claim 1 further comprising operating the cell with a cation permselective membrane as the separator.
Claim 16
Dependent Claim
18 words
The process according to claim 1 further comprising operating the cell with water as the aqueous catholyte solution.
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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) | 1994-08-19 | 1995-02-18 | 1995-08-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-08-19 | 1999-02-18 | 1999-08-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-08-19 | 2003-02-18 | 2003-08-20 | $7700.00 | Window Closed / Lapsed |