WO1992017399A1 - Procede de production de boues d'hypochlorite de sodium - Google Patents

Procede de production de boues d'hypochlorite de sodium Download PDF

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Publication number
WO1992017399A1
WO1992017399A1 PCT/US1992/001041 US9201041W WO9217399A1 WO 1992017399 A1 WO1992017399 A1 WO 1992017399A1 US 9201041 W US9201041 W US 9201041W WO 9217399 A1 WO9217399 A1 WO 9217399A1
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WO
WIPO (PCT)
Prior art keywords
sodium hypochlorite
weight
sodium
percent
solution
Prior art date
Application number
PCT/US1992/001041
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English (en)
Inventor
Budd L. Duncan
Richard C. Ness
Original Assignee
Olin Corporation
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Olin Corporation filed Critical Olin Corporation
Publication of WO1992017399A1 publication Critical patent/WO1992017399A1/fr

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B11/00—Oxides or oxyacids of halogens; Salts thereof
    • C01B11/04—Hypochlorous acid
    • C01B11/06—Hypochlorites
    • C01B11/062—Hypochlorites of alkali metals

Definitions

  • This invention is related to the production of pure concentrated slurries of sodium hypochlorite. More particularly, this invention is related to the production of pure concentrated slurries of sodium hypochlorite from . pure concentrated solutions of hypochlorous acid.
  • sodium hypochlorite solutions are widely used in bleaching and disinfectant formulations for home and industry. In addition to laundry applications in households and commercial laundries, sodium hypochlorite solutions are employed in hard surface, dairy, and bottle cleansers and sanitizers. These solutions can also be used in treating potable and waste water as well as treating wastes from metal processing operations such as plating.
  • the reaction mixture contains equal amounts of sodium chloride.
  • a large number of processes have been developed to recover concentrated solutions of sodium hypochlorite by separating solid sodium chloride crystals from the reaction mixtures.
  • a typical process is that of U.S. Patent No. 4,780,303, issued October 25, 1988 to J. Dugua. In this process, chlorine is reacted with a solution of sodium hydroxide in which the concentration is from 20 to 50% by weight of NaOH.
  • the first stage of this process is carried out in an absorption column and the process produces a solution containing sodium hypochlorite in which the NaOCl is limited to 15% by weight and an excess of NaOH.
  • the sodium hypochlorite solution is fed to a crystallizer along with 48-50 weight percent NaOH and pure chlorine.
  • the solution of sodium hypochlorite formed contains large crystals of NaCl which are separated to provide a sodium hypochlorite solution containing 25% by weight of NaOCl.
  • crystals of sodium pentahydrate form and a slurry of sodium hypochlorite pentahydrate crystals in a solution of sodium hypochlorite results which contain about 23% by weight NaOCl and about 11% by weight of NaCl.
  • R.H. Walsh in U.S. Patent No. 3,498,924 prepared solid NaOCl compositions by reacting sodium hydroxide with hypochlorous acid.
  • hypochlorous acid solutions which are free of chloride ions, are reacted with concentrated sodium hydroxide at low temperatures such as 0°C to produce a solution of sodium hypochlorite.
  • the sodium hypochlorite solution is then vacuum-evaporated at temperatures below 45°C and low pressures of about 1mm Hg to prepare solid hydrated sodium hypochlorite.
  • the solid hydrated sodium hypochlorite for example, sodium hypochlorite dihydrate, is further dried to anhydrous sodium hypochlorite or mixed with solid sodium hydroxide to form a basic solid sodium hypochlorite.
  • the process of Walsh employs hypochlorous acid solutions having concentrations up to about 300 grams per liter of HOCl per liter, and commonly aqueous solutions containing 125 to 225 grams of hypochlorous acid per liter.
  • This process initially produces sodium hypochlorite solutions containing about 20-27 percent by weight of NaOCl when using an aqueous solution of sodium hydroxide containing 50% by weight of NaOH.
  • the process requires the separation of solid impurities and then the concentration of the solution by heating under vacuum to prepare the solid hydrated sodium hypochlorite.
  • sodium hypochlorite compositions having increased concentrations of NaOCl which can be readily produced, shipped and stored.
  • high strength sodium hypochlorite compositions having a solid form of sodium hypochlorite which have improved stability.
  • high strength sodium hypochlorite compositions having greatly reduced amounts of sodium chloride there is a need for a process for producing high strength sodium hypochlorite compositions having improved yields and reduced product decomposition.
  • a process for producing sodium hypochlorite slurries which comprises admixing at a temperature below about 25°C. a hypochlorite acid solution having a concentration of 35 percent or greater by weight of HOCl with sodium hydroxide to produce a slurry of sodium hypochlorite pentahydrate in an aqueous solution of sodium hypochlorite, the sodium hypochlorite being present in a concentration of at least 35 percent by weight of NaOCl and containing less than about 2 percent by weight of NaCl.
  • the novel process of the present invention employs as the starting material a concentrated solution of hypochlorous acid, HOCl.
  • the method for producing high purity concentrated HOCl solutions is that in which gaseous mixtures, having high concentrations of hypochlorous acid vapors and chlorine monoxide gas and controlled amounts of water vapor are produced, for example, by the process described by J. P. Brennan et al in U.S. Patent No. 4,147,761.
  • the concentrated hypochlorous acid solutions employed as one reactant have a concentration in the range of from about 35 to about 60, and preferably from about 40 to about 55 percent by weight of HOCl.
  • the solution is substantially free of ionic impurities such as chloride ions and alkali metal ions and has low concentrations of dissolved chlorine.
  • concentrations of the chloride ion are less than about 50 parts per million and the alkali metal ion concentration is less than about 50 parts per million.
  • the dissolved chlorine concentration in the hypochlorite acid solution is less than about 2 percent, and preferably less than about 1 percent by weight.
  • the second reactant in the novel process of the present invention is sodium hydroxide.
  • the sodium hydroxide is employed as an aqueous solution or slurry containing from about 40 to about 80 percent by weight of NaOH, and preferably form about 40 to about 60 percent by weight of NaOH.
  • the sodium hydroxide employed is, for example, an industrial grade having low concentrations of impurities such as sodium chloride.
  • This novel process of the present invention is operated continuously by admixing the hypochlorous acid solution, containing at least 35% by weight of HOCl, with the concentrated sodium hydroxide solution.
  • the reaction mixture formed is a slurry of sodium pentahydrate crystals in a saturated solution of sodium hypochlorite.
  • the reaction is carried out at temperatures below about 25°C, for example, in the range of from about 15°C to about 23°C, and preferably, at from about 18°C to about 23 ⁇ C. In this single step process the slurries are recovered directly without further processing.
  • Slurries of sodium hypochlorite pentahydrate having increased concentrations of solids can be produced by reacting the concentrated solution of hypochlorous acid with the sodium hydroxide at temperatures in the range of from about 25° to about 35°C, and preferably at temperatures of from about 26° to about 30 ⁇ C.
  • a saturated solution of sodium hypochlorite is formed containing at least 35% by weight of NaOCl. This solution is then cooled to a temperature below about 25°C. to produce a slurry of sodium pentahydrate crystals in a saturated solution of sodium hypochlorite having high concentrations of solids.
  • reaction of the hypochlorous acid solutions having concentrations of above 35% by weight of HOCl
  • concentrated solution of sodium hydroxide can result in the occurence of supersaturation in the solutions of sodium hypochlorite.
  • solid sodium hypochlorite particles are added to the initial reaction mixture to avoid or minimize the occurrence of supersaturation.
  • the seeding or the initial crystallization in a supersaturated solution results in the formation of agglomerates of sodium pentahydrate crystals which do not flow.
  • Suitable total solids concentrations include, for example, slurries having total solids concentrations in the range of from about 5 to about 80, and preferably, from about 10 to about 60, and more preferably from about 30 to about 50 percent.
  • the novel process of the present invention is operated to a residual alkalinity to minimize decomposition of the saturated solution of sodium hypochlorite.
  • the slurries contain a residual of hydroxide ions of from about 0.2 to about 1.5%, and preferably from about 0.2 to about 0.5% percent by weight.
  • the reaction can be controlled by the use of a pH probe which monitors the residual alkalinity of the reaction mixture.
  • a 37% solution of sodium hypochlorite (approximately 300 mis) was prepared in a 0.5 liter jacketed stirred reactor batchwise by admixing a 45% solution of hypochlorous acid (HOCl) and a 50% solution of NaOH at a temperature of 19°C. A small portion (approximately 5 mis) of this material was removed and frozen using liquid nitrogen. When this frozen material was returned to the reactor, the contents of the vessel were converted from a solution to a slurry containing 45% solids. The temperature in the reactor rose to 23°C. Controlled flows of both the HOCl and NaOH solutions were then continuously added to the reactor, a 34% to 37% NaOCl slurry overflowed into a collection vessel.
  • HOCl hypochlorous acid

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Geology (AREA)
  • Inorganic Chemistry (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

Abstract

Selon un procédé de production de boues d'hypochlorite de sodium, on mélange à de l'hydroxyde de sodium, à une température inférieure à environ 25 °C, une solution d'acide hypochloreux présentant une concentration de HOCl égale ou supérieure à 35 % en poids. La réaction produit une boue de pentahydrate d'hypochlorite de sodium dans une solution aqueuse d'hypochlorite de sodium dans laquelle la concentration d'hypochlorite de sodium est égale ou supérieure à 35 % en poids de NaOCl. Ces boues d'hypochlorite de sodium présentent une stabilité améliorée et contiennent des quantités fortement réduites de chlorure de sodium. Le procédé permet d'obtenir des compositions concentrées et de grande pureté d'hypochlorite de sodium présentant des rendements améliorés et une décomposition réduite du produit.
PCT/US1992/001041 1991-03-26 1992-02-10 Procede de production de boues d'hypochlorite de sodium WO1992017399A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US67537391A 1991-03-26 1991-03-26
US675,373 1991-03-26

Publications (1)

Publication Number Publication Date
WO1992017399A1 true WO1992017399A1 (fr) 1992-10-15

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Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US1992/001041 WO1992017399A1 (fr) 1991-03-26 1992-02-10 Procede de production de boues d'hypochlorite de sodium

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AU (1) AU1769492A (fr)
WO (1) WO1992017399A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2014070928A2 (fr) 2012-10-31 2014-05-08 Olin Corporation Composition d'hypochlorite de sodium et procédé de stockage et de transport d'hypochlorite de sodium
WO2016201397A1 (fr) * 2015-06-10 2016-12-15 Olin Corporation Compositions d'hypochlorite de sodium

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3498924A (en) * 1966-03-10 1970-03-03 Ppg Industries Inc Process for preparing stable sodium hypochlorites
US4147761A (en) * 1978-03-09 1979-04-03 Olin Corporation Hypochlorous acid process using sweep reactor
US4428918A (en) * 1980-12-22 1984-01-31 Solvay & Cie. Process and plant for the preparation of concentrated aqueous solutions of alkali metal hypochlorite
WO1990005111A1 (fr) * 1988-10-31 1990-05-17 Olin Corporation Procede ameliore de production d'acide hypochloreux
US5055285A (en) * 1990-02-01 1991-10-08 Olin Corporation Process for the production of highly pure concentrated solutions of potassium hypochlorite
US5102648A (en) * 1990-03-02 1992-04-07 Olin Corporation Process for the production of lithium hypochloride

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3498924A (en) * 1966-03-10 1970-03-03 Ppg Industries Inc Process for preparing stable sodium hypochlorites
US4147761A (en) * 1978-03-09 1979-04-03 Olin Corporation Hypochlorous acid process using sweep reactor
US4428918A (en) * 1980-12-22 1984-01-31 Solvay & Cie. Process and plant for the preparation of concentrated aqueous solutions of alkali metal hypochlorite
WO1990005111A1 (fr) * 1988-10-31 1990-05-17 Olin Corporation Procede ameliore de production d'acide hypochloreux
US5055285A (en) * 1990-02-01 1991-10-08 Olin Corporation Process for the production of highly pure concentrated solutions of potassium hypochlorite
US5102648A (en) * 1990-03-02 1992-04-07 Olin Corporation Process for the production of lithium hypochloride

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2014070928A2 (fr) 2012-10-31 2014-05-08 Olin Corporation Composition d'hypochlorite de sodium et procédé de stockage et de transport d'hypochlorite de sodium
EP2914545A4 (fr) * 2012-10-31 2016-06-08 Olin Corp Composition d'hypochlorite de sodium et procédé de stockage et de transport d'hypochlorite de sodium
US9434616B2 (en) 2012-10-31 2016-09-06 Olin Corporation Sodium hypochlorite composition and method of storing and transporting sodium hypochlorite
WO2016201397A1 (fr) * 2015-06-10 2016-12-15 Olin Corporation Compositions d'hypochlorite de sodium

Also Published As

Publication number Publication date
AU1769492A (en) 1992-11-02

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