US3829557A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Production of chlorine dioxide
Assignee: Tenneco Canada Inc
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Filing: 1971-07-28
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Granted: 1974-08-13
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Expires: 1991-07-28
Abstract
Abstract Chlorine dioxide is produced in a two-stage operation. In the first stage sodium chlorate and hydrochloric acid are reacted in aqueous solution at elevated temperature to form a gaseous mixture of chlorine dioxide, chlorine and evaporated water vapor and to form sodium chloride in the reaction zone of the first stage. In the second stage, a second reaction solution is formed containing sodium chlorate, sodium chloride and sulphuric acid, the sodium chloride being constituted at least in part by the sodium chloride formed in the first stage. Sodium sulphate and a gaseous mixture of chlorine dioxide, chlorine and water vapor are formed upon heating the second reaction solution. Chlorine dioxide is recovered from the gaseous mixtures formed in the two stages.
Inventors
- 👤 J Winfield
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 00:18
CPC Classifications
C; C01; C01B; C01B11/00; C01B11/02; C01B11/022; C01B11/023; C01B11/025
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
33 words
The process of claim 1 wherein each of said first and second reaction zones is subjected to a reduced pressure and each of said reaction mediums is maintained substantially at its boiling temperature.
Claim 2
Dependent Claim
207 words
A process for the production of chlorine dioxide which comprises forming first aqueous reaction medium containing sodium chlorate and hydrochloric acid in a first reaction zone by feeding to said first reaction zone hydrochloric acid and an aqueous solution of said alkali metal chlorate, the quantity of hydrochloric acid being sufficient to establish an acidity of about 0.05 to about 1N in said first aqueous reaction medium, heating said aqueous reaction medium to effect reaction between said sodium chlorate and hydrochloric acid to generate thereby chlorine dioxide and chlorine and to evaporate water from said medium, removing said chlorine dioxide and chlorine from said first reaction zone as a gaseous mixturE consisting of said chlorine dioxide and chlorine and said evaporated water, recovering by-product sodium chloride from said reaction zone, forming a second aqueous reaction medium in a second reaction zone, said second reaction medium containing sodium chlorate, sodium chloride and sulphuric acid, at least part of said latter sodium chloride being provided by said recovered by-product sodium chloride, generating chlorine dioxide and chlorine from said second reaction medium, recovering said latter chlorine dioxide and chlorine from said second reaction zone, and recovering chlorine dioxide from the gaseous mixtures removed from said first and second reaction zones.
Claim 3
Dependent Claim
63 words
The process of claim 3 wherein said first aqueous reaction medium is heated to effect reaction between said sodium chlorate and hydrochloric acid to generate thereby chlorine dioxide and chlorine, to evaporate water from said medium and to deposit sodium chloride in said first reaction zone, and said deposited sodium chloride is recovered from said first reaction zone as said by-product sodium chloride.
Claim 4
Dependent Claim
27 words
The process of claim 3 wherein said chlorine dioxide and chlorine generated in said second reaction zone is removed therein in gaseous admixture with an inert gas.
Claim 5
Dependent Claim
25 words
The process of claim 4 wherein the aqueous reaction medium in said second reaction zone has an acidity of from about 2 to about 4.8N.
Claim 6
Dependent Claim
33 words
The process of claim 1 wherein all of said solid deposited sodium chloride is passed to said second reaction zone and constitutes all of the sodium chloride requirement of said second reaction medium.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-08-12 | 1978-02-11 | 1978-08-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-08-12 | 1982-02-11 | 1982-08-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-08-12 | 1986-02-11 | 1986-08-13 | $7700.00 | Window Closed / Lapsed |