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US3852033A
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Process for controlling chlorate and hydrogen ion content in the manufacture of chlorine dioxide from alkali metal chlorate and an inorganic acid
Assignee: Mo och Domsjo AB
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Filing: 1973-07-09
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Granted: 1974-12-03
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Expires: 1993-07-09
Abstract
Abstract A process for controlling the chlorate and hydrogen ion content of the reaction mixture in the manufacture of chlorine dioxide from alkali metal chlorate and inorganic acid, to improve the yield of chlorine dioxide and minimize side reactions. The concentration of chlorate ions and hydrogen ions in the reaction mixture is monitored calorimetrically, the addition to the system of chlorate, reducing agent and inorganic acid is controlled in a manner to maintain the chlorate and hydrogen ion concentrations thereof at a desired level.
Inventors
- 👤 B Hultman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 17:17
CPC Classifications
C; C01; C01B; C01B11/00; C01B11/02; C01B11/022; C01B11/023; C01B11/025; Y; Y10; Y10T; Y10T436/00; Y10T436/12
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
105 words
A PROCESS FOR MEASURING THE CHLORATE ION AND THE HYDROGEN ION CONCENTRATION OF CHLORINE DIOXIDE-PRODUCING REACTION MIXTURES COMPRISING ALKALI METAL CHLORATE, REDUCING AGENT, AND INORGANIC ACID BY A CALORIMETRIC DETERMINATION, WHICH COMPRISES WITHDRAWING A SAMPLE OF THE REACTION MIXTURE, COMBINING IT WITH LIBERATION OF HEAT, MEASURING THE HEAT LIBERATED, AND IONS WITH LIBERATION OF HEAT, MEASURING THE HEAT LIBERATED, AND FROM THIS HEAT DETERMINING THE CONCENTRATION OF CHLORATE ION, WITHDRAWING ANOTHER SAMPLE OF THE REACTION MIXTURE, COMBINING IT WITH A HYDROGEN ION REAGENT WHICH REACTS WITH HYDROGEN IONS WITH LIBERATION OF HEAT, MEASURING HEAT LIBERATED AND FROM THIS HEAT DETERMINING THE CONCENTRATION OF HYDROGEN ION.
Claim 2
Dependent Claim
105 words
A PROCESS FOR MEASURING THE CHLORATE ION AND THE HYDROGEN ION CONCENTRATION OF CHLORINE DIOXIDE-PRODUCING REACTION MIXTURES COMPRISING ALKALI METAL CHLORATE, REDUCING AGENT, AND INORGANIC ACID BY A CALORIMETRIC DETERMINATION, WHICH COMPRISES WITHDRAWING A SAMPLE OF THE REACTION MIXTURE, COMBINING IT WITH LIBERATION OF HEAT, MEASURING THE HEAT LIBERATED, AND IONS WITH LIBERATION OF HEAT, MEASURING THE HEAT LIBERATED, AND FROM THIS HEAT DETERMINING THE CONCENTRATION OF CHLORATE ION, WITHDRAWING ANOTHER SAMPLE OF THE REACTION MIXTURE, COMBINING IT WITH A HYDROGEN ION REAGENT WHICH REACTS WITH HYDROGEN IONS WITH LIBERATION OF HEAT, MEASURING HEAT LIBERATED AND FROM THIS HEAT DETERMINING THE CONCENTRATION OF HYDROGEN ION.
Claim 3
Dependent Claim
40 words
A process in accordance with claim 1, which comprises controlling the amount of alkali metal chlorate and/or reducing agent and/or acid to the reaction mixture to maintain chlorate and hydrogen ion concentration at a desired level in the reaction mixture.
Claim 4
Dependent Claim
23 words
A process in accordance with claim 1, in which the calorimetric determination is carried out with a calorimeter determining the heat liberated adiabatically.
Claim 5
Dependent Claim
23 words
A process in accordance with claim 1, in which the calorimetric determination is carried out with a calorimeter determining the heat liberated isothermally.
Claim 6
Dependent Claim
35 words
A process in accordance with claim 1, in which the calorimetric determination is carried out with a calorimeter which converts the heat liberated to an electric signal which is a function of the heat liberated.
Claim 7
Dependent Claim
33 words
A process in accordance with claim 1, in which the chlorate ion reagent is selected from the group consisting of sulfuric acid solutions of ferrous sulphate, hydrazine hydrogen sulphate, hydroxylamine, and mixtures thereof.
Claim 8
Dependent Claim
22 words
A process in accordance with claim 1, in which the hydrogen ion reagent is a strong base which reacts exothermically with acids.
Claim 9
Dependent Claim
30 words
A process in accordance with claim 7, in which the hydrogen ion reagent is a strong base selected from the group consisting of alkali metal and alkaline earth metal hydroxides.
Claim 10
Dependent Claim
33 words
A process in accordance with claim 1, in which the amount of chlorate ion reagent or hydrogen ion reagent added is in excess to ensure complete liberation of the stoichiometric amount of heat.
Claim 11
Dependent Claim
23 words
A process in accordance with claim 1, in which the sampling and measuring are applied to the reaction mixture from time to time.
Claim 12
Dependent Claim
20 words
A process in accordance with claim 1, in which the sampling and measuring are applied to the reaction mixture continuously.
Claim 13
Dependent Claim
27 words
A process in accordance with claim 1, in which the reducing agent is sodium chloride and/or sulphur dioxide or methanol, and the inorganic acid is sulphuric acid.
Claim 14
Dependent Claim
101 words
A process for control of a chlorine dioxide-producing reaction system comprising an alkali metal chlorate, inorganic acid and reducing agent, comprising determining calorimetrically the concentrations of chlorate and hydrogen ions in the reaction mixture, and according to the concentrations thus determined controlling the addition of alkali metal chlorate, reducing agent and acid to the system so as to maintain the chlorate ion and hydrogen ion concentrations thereof at a level to favor the reactions resulting in the production of chlorine dioxide, and minimize side reactions resulting in loss of chlorate, such as in the formation of chlorine and alkali metal chlorides.
Claim 15
Dependent Claim
101 words
A process for control of a chlorine dioxide-producing reaction system comprising an alkali metal chlorate, inorganic acid and reducing agent, comprising determining calorimetrically the concentrations of chlorate and hydrogen ions in the reaction mixture, and according to the concentrations thus determined controlling the addition of alkali metal chlorate, reducing agent and acid to the system so as to maintain the chlorate ion and hydrogen ion concentrations thereof at a level to favor the reactions resulting in the production of chlorine dioxide, and minimize side reactions resulting in loss of chlorate, such as in the formation of chlorine and alkali metal chlorides.
Claim 16
Dependent Claim
17 words
A process in accordance with claim 13, in which the reaction system is a batch reaction system.
Claim 17
Dependent Claim
18 words
A process in accordance with claim 13, in which the reaction system is a continuous flow reaction system.
Claim 18
Dependent Claim
32 words
A process in accordance with claim 13, wherein the chlorate ion reagent is selected from the Group consisting of sulphuric acid solution of ferrous sulphate, hydrazine hydrogen sulphate, hydroxylamine and mixtures thereof.
Claim 19
Dependent Claim
26 words
A process in accordance with claim 13, wherein the hydrogen ion reagent is selected from the group consisting of alkali metal and alkaline earth metal hydroxides.
Claim 20
Dependent Claim
23 words
A process in accordance with claim 13, in which the calorimetric determination is carried out with a calorimeter determining the heat liberated isothermally.
Claim 21
Dependent Claim
23 words
A process in accordance with claim 13, in which the calorimetric determination is carried out with a calorimeter determining the heat liberated adiabatically.
Claim 22
Independent Claim
186 words
An apparatus for continuously producing chlorine dioxide from alkali metal chlorate, inorganic acid and reducing agent, monitoring chlorate ion and hydrogen ion concentration in the reaction mixture, and controlling addition of alkali metal chlorate, inorganic acid, and reducing agent to maintain a predetermined chlorate ion and hydrogen ion concentration in the reaction mixture, comprising, in combination, at least one reactor having inlet lines for aqueous alkali metal chlorate solution, reducing agent, and inorganic acid, and discharge lines for chlorine dioxide and residual acid solution; at least one absorption tower for flow of water countercurrently to flow of chlorine dioxide gas in the tower, and an outlet for aqueous chlorine dioxide solution; and a calorimetric analysis system in continuous fluid flow connection with the reactor for monitoring by a calorimetric determination the hydrogen ion and chlorate ion concentrations in the reaction mixture in the reactor; and means for controlling the feed of alkali metal chlorate, inorganic acid and reducing agent to the reactor, so as to maintain an optimum chlorate and hydrogen ion concentration in the reactor, and a minimum chlorate ion in the exiting residual acid.
Claim 23
Independent Claim
186 words
An apparatus for continuously producing chlorine dioxide from alkali metal chlorate, inorganic acid and reducing agent, monitoring chlorate ion and hydrogen ion concentration in the reaction mixture, and controlling addition of alkali metal chlorate, inorganic acid, and reducing agent to maintain a predetermined chlorate ion and hydrogen ion concentration in the reaction mixture, comprising, in combination, at least one reactor having inlet lines for aqueous alkali metal chlorate solution, reducing agent, and inorganic acid, and discharge lines for chlorine dioxide and residual acid solution; at least one absorption tower for flow of water countercurrently to flow of chlorine dioxide gas in the tower, and an outlet for aqueous chlorine dioxide solution; and a calorimetric analysis system in continuous fluid flow connection with the reactor for monitoring by a calorimetric determination the hydrogen ion and chlorate ion concentrations in the reaction mixture in the reactor; and means for controlling the feed of alkali metal chlorate, inorganic acid and reducing agent to the reactor, so as to maintain an optimum chlorate and hydrogen ion concentration in the reactor, and a minimum chlorate ion in the exiting residual acid.
Claim 24
Dependent Claim
39 words
An apparatus in accordance with claim 20, in which the calorimetric analysis system measures the heat of reaction liberated by the reaction of chlorate ion with a chlorate ion reagent, and hydrogen ion with a hydrogen ion reagent, isothermically.
Claim 25
Dependent Claim
39 words
An apparatus in accordance with claim 20, in which the calorimetric analysis system measures the heat of reaction liberated by the reaction of chlorate ion with a chlorate ion reagent, and hydrogen ion with a hydrogen ion reagent, adiabatically.
Claim 26
Dependent Claim
75 words
An apparatus in accordance with claim 20, in which the calorimetric analysis system comprises a peristaltic pump for withdrawing an analysis sample from the reactor, and for withdrawing a like portion of chlorate ion reagent or hydrogen ion reagent for mixing therewith; means for bringing both sample and reagent to the same temperature; a mixing vessel where they are mixed together with liberation of heat; and a calorimeter for measuring the heat that is liberated.
Claim 27
Dependent Claim
30 words
An apparatus according to claim 23 comprising a thermopile to which the heat liberated is transferred and transmitted as a voltage pulse, and a voltmeter for measuring the voltage pulse.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-12-02 | 1978-06-03 | 1978-12-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-12-02 | 1982-06-03 | 1982-12-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-12-02 | 1986-06-03 | 1986-12-03 | $7700.00 | Window Closed / Lapsed |