Sodium chlorite

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Sodium chlorite
Na+.svg
Chlorition.png
The sodium cation Sodium-3D.png
The sodium cation
Space-filling model of the chlorite anion Chlorite-3D-vdW.png
Space-filling model of the chlorite anion
Sodium chlorite 450g.jpg
Names
IUPAC name
Sodium chlorite
Other names
Chlorous acid, sodium salt
Textone
Identifiers
3D model (JSmol)
ChEBI
ChemSpider
ECHA InfoCard 100.028.942 OOjs UI icon edit-ltr-progressive.svg
EC Number
  • 231-836-6
KEGG
PubChem CID
RTECS number
  • VZ4800000
UNII
UN number 1496
  • InChI=1S/ClHO2.Na/c2-1-3;/h(H,2,3);/q;+1/p-1 Yes check.svgY
    Key: UKLNMMHNWFDKNT-UHFFFAOYSA-M Yes check.svgY
  • InChI=1/ClHO2.Na/c2-1-3;/h(H,2,3);/q;+1/p-1
    Key: UKLNMMHNWFDKNT-REWHXWOFAT
  • [Na+].[O-]Cl=O
Properties
NaClO2
Molar mass 90.442 g/mol (anhydrous)
144.487 g/mol (trihydrate)
Appearancewhite solid
Odor odorless
Density 2.468 g/cm3, solid
Melting point anhydrous decomposes at 180–200 °C
trihydrate decomposes at 38 °C
75.8 g/100 mL (25 °C)
122 g/100 mL (60 °C)
Solubility slightly soluble in methanol, ethanol
Acidity (pKa)10-11
Structure
monoclinic
Thermochemistry
-307.0 kJ/mol
Pharmacology
D03AX11 ( WHO )
Hazards
Occupational safety and health (OHS/OSH):
Ingestion hazards
Category 3
Inhalation hazards
Category 2
Eye hazards
Category 1
Skin hazards
Category 1B
GHS labelling:
GHS-pictogram-rondflam.svg GHS-pictogram-acid.svg GHS-pictogram-skull.svg GHS-pictogram-pollu.svg
Danger
H272, H301, H310, H314, H330, H400
P210, P220, P221, P260, P262, P264, P270, P271, P273, P280, P284, P301+P330+P331, P303+P361+P353, P305+P351+P338, P310, P361, P363, P370+P378, P391, P403+P233, P405, P501
NFPA 704 (fire diamond)
NFPA 704.svgHealth 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g. chloroformFlammability 0: Will not burn. E.g. waterInstability 1: Normally stable, but can become unstable at elevated temperatures and pressures. E.g. calciumSpecial hazard OX: Oxidizer. E.g. potassium perchlorate
2
0
1
OX
Flash point Non-flammable
Lethal dose or concentration (LD, LC):
350 mg/kg (rat, oral)
Safety data sheet (SDS) SDS
Related compounds
Other anions
Sodium chloride
Sodium hypochlorite
Sodium chlorate
Sodium perchlorate
Other cations
Potassium chlorite
Barium chlorite
Related compounds
 Chlorine dioxide
Chlorous acid
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
X mark.svgN  verify  (what is  Yes check.svgYX mark.svgN ?)

Sodium chlorite (NaClO2) is a chemical compound used in the manufacturing of paper and as a disinfectant.

Use

The main application of sodium chlorite is the generation of chlorine dioxide for bleaching and stripping of textiles, pulp, and paper. It is also used for disinfection of municipal water treatment plants after conversion to chlorine dioxide. [1] : 2  An advantage in this application, as compared to the more commonly used chlorine, is that trihalomethanes (such as chloroform) are not produced from organic contaminants. [1] : 25, 33  Chlorine dioxide generated from sodium chlorite is approved by FDA under some conditions for disinfecting water used to wash fruits, vegetables, and poultry. [2] [ full citation needed ] [3]

Sodium chlorite, NaClO2, sometimes in combination with zinc chloride, also finds application as a component in therapeutic rinses, mouthwashes, [4] [5] toothpastes and gels, mouth sprays, as preservative in eye drops, [6] and in contact lens cleaning solution under the trade name Purite.

It is also used for sanitizing air ducts and HVAC/R systems and animal containment areas (walls, floors, and other surfaces).

Chemical reagent

In organic synthesis, sodium chlorite is frequently used as a reagent in the Pinnick oxidation for the oxidation of aldehydes to carboxylic acids. The reaction is usually performed in monosodium phosphate buffered solution in the presence of a chlorine scavenger (usually 2-methyl-2-butene). [7]

In 2005, sodium chlorite was used as an oxidizing agent to convert alkyl furans to the corresponding 4-oxo-2-alkenoic acids in a simple one pot synthesis. [8]

Acidified sodium chlorite

Mixing sodium chlorite solution with a weak food-grade acid solution (commonly citric acid), both stable, produces short-lived acidified sodium chlorite (ASC) which has potent decontaminating properties. Upon mixing the main active ingredient, chlorous acid is produced in equilibrium with chlorite anion. The proportion varies with pH, temperature, and other factors, ranging from approximately 5–35% chlorous acid with 65–95% chlorite; more acidic solutions result in a higher proportion of chlorous acid. Chlorous acid breaks down to chlorine dioxide which in turn breaks down to chlorite anion and ultimately chloride anion. ASC is used for sanitation of the hard surfaces which come in contact with food and as a wash or rinse for a variety of foods including red meat, poultry, seafood, fruits and vegetables. Because the oxo-chlorine compounds are unstable when properly prepared, there should be no measurable residue on food if treated appropriately. [9] [10] ASC also is used as a teat dip for control of mastitis in dairy cattle. [11]

Use in public crises

The U.S. Army Natick Soldier Research, Development, and Engineering Center produced a portable "no power required" method of generating chlorine dioxide, known as ClO2, gas, described as one of the best biocides available for combating contaminants, which range from benign microbes and food pathogens to Category A Bioterror agents. In the weeks after the 9/11 attacks when anthrax was sent in letters to public officials, hazardous materials teams used ClO2 to decontaminate the Hart Senate Office Building, and the Brentwood Postal Facility. [12]

In addressing the COVID-19 pandemic, the U.S. Environmental Protection Agency has posted a list of many disinfectants that meet its criteria for use in environmental measures against the causative coronavirus. [13] [14] Some are based on sodium chlorite that is activated into chlorine dioxide, though differing formulations are used in each product. Many other products on the EPA list contain sodium hypochlorite, which is similar in name but should not be confused with sodium chlorite because they have very different modes of chemical action.

Safety

Sodium chlorite, like many oxidizing agents, should be protected from inadvertent contamination by organic materials to avoid the formation of an explosive mixture. The chemical is stable in pure form and does not explode on percussive impact, unless organic contaminants are present, such as on a greasy hammer striking the chemical on an anvil. [15] It also easily ignites by friction if combined with a reducing agent like powdered sugar, sulfur or red phosphorus.

Toxicity

Sodium chlorite is a strong oxidant and can therefore be expected to cause clinical symptoms similar to the well known sodium chlorate: methemoglobinemia, hemolysis, kidney failure. [16] A dose of 10-15 grams of sodium chlorate can be lethal. [17] Methemoglobemia had been demonstrated in rats and cats, [18] and recent studies by the EMEA have confirmed that the clinical symptomatology is very similar to the one caused by sodium chlorate in rats, mice, rabbits, and green monkeys. [19]

There is only one human case in the medical literature of chlorite poisoning. [20] It seems to confirm that the toxicity is equal to sodium chlorate. From the analogy with sodium chlorate, even small amounts of about 1 gram can be expected to cause nausea, vomiting and even life-threatening hemolysis in glucose-6-phosphate dehydrogenase deficient persons.

The EPA has set a maximum contaminant level of 1 milligram of chlorite per liter (1 mg/L) in drinking water. [21]

Sellers of “Miracle Mineral Solution”, a mixture of sodium chlorite and citric acid also known as "MMS" that is promoted as a cure-all have been convicted, fined, or otherwise disciplined in multiple jurisdictions around the world. MMS products were variously referred to as snake oil and complete quackery. The U.S. Food and Drug Administration has issued multiple warnings against consuming MMS. [22] [23] [24] [25] [26] [27] [28] [29] [30]

Manufacture

The free acid, chlorous acid, HClO2, is only stable at low concentrations. Since it cannot be concentrated, it is not a commercial product. However, the corresponding sodium salt, sodium chlorite, NaClO2 is stable and inexpensive enough to be commercially available. The corresponding salts of heavy metals (Ag+, Hg+, Tl+, Pb2+, and also Cu2+ and NH4+) decompose explosively with heat or shock.

Sodium chlorite is derived indirectly from sodium chlorate, NaClO3. First, sodium chlorate is reduced to chlorine dioxide, typically in a strong acid solution using reducing agents such as sodium sulfite, sulfur dioxide, or hydrochloric acid. This intermediate is then absorbed into a solution of aqueous sodium hydroxide where another reducing agent converts it to sodium chlorite. Even hydrogen peroxide can be used as the reducing agent, giving oxygen gas as its byproduct rather than other inorganic salts or materials that could contaminate the desired product. [31]

General references

Related Research Articles

<span class="mw-page-title-main">Chlorine</span> Chemical element, symbol Cl and atomic number 17

Chlorine is a chemical element; it has symbol Cl and atomic number 17. The second-lightest of the halogens, it appears between fluorine and bromine in the periodic table and its properties are mostly intermediate between them. Chlorine is a yellow-green gas at room temperature. It is an extremely reactive element and a strong oxidising agent: among the elements, it has the highest electron affinity and the third-highest electronegativity on the revised Pauling scale, behind only oxygen and fluorine.

The chlorite ion, or chlorine dioxide anion, is the halite with the chemical formula of ClO−
2. A chlorite (compound) is a compound that contains this group, with chlorine in the oxidation state of +3. Chlorites are also known as salts of chlorous acid.

<span class="mw-page-title-main">Oxidizing agent</span> Chemical compound used to oxidize another substance in a chemical reaction

An oxidizing agent is a substance in a redox chemical reaction that gains or "accepts"/"receives" an electron from a reducing agent. In other words, an oxidizer is any substance that oxidizes another substance. The oxidation state, which describes the degree of loss of electrons, of the oxidizer decreases while that of the reductant increases; this is expressed by saying that oxidizers "undergo reduction" and "are reduced" while reducers "undergo oxidation" and "are oxidized". Common oxidizing agents are oxygen, hydrogen peroxide, and the halogens.

<span class="mw-page-title-main">Sodium hypochlorite</span> Chemical compound (known in solution as bleach)

Sodium hypochlorite, commonly known in a dilute solution as (chlorine) bleach, is an alkaline inorganic chemical compound with the formula NaOCl, consisting of a sodium cation and a hypochlorite anion. It may also be viewed as the sodium salt of hypochlorous acid. The anhydrous compound is unstable and may decompose explosively. It can be crystallized as a pentahydrate NaOCl·5H
2O, a pale greenish-yellow solid which is not explosive and is stable if kept refrigerated.

<span class="mw-page-title-main">Potassium chlorate</span> Chemical compound

Potassium chlorate is a compound containing potassium, chlorine and oxygen, with the molecular formula KClO3. In its pure form, it is a white crystalline substance. After sodium chlorate, it is the second most common chlorate in industrial use. It is a strong oxidizing agent and its most important application is in safety matches. In other applications it is mostly obsolete and has been replaced by safer alternatives in recent decades. It has been used

<span class="mw-page-title-main">Chlorine dioxide</span> Chemical compound

Chlorine dioxide is a chemical compound with the formula ClO2 that exists as yellowish-green gas above 11 °C, a reddish-brown liquid between 11 °C and −59 °C, and as bright orange crystals below −59 °C. It is usually handled as an aqueous solution. It is commonly used as a bleach. More recent developments have extended its applications in food processing and as a disinfectant.

<span class="mw-page-title-main">Hypochlorite</span> Ion

In chemistry, hypochlorite, or chloroxide is an anion with the chemical formula ClO−. It combines with a number of cations to form hypochlorite salts. Common examples include sodium hypochlorite and calcium hypochlorite. The Cl-O distance in ClO− is 1.69 Å.

<span class="mw-page-title-main">Sodium chlorate</span> Chemical compound

Sodium chlorate is an inorganic compound with the chemical formula NaClO3. It is a white crystalline powder that is readily soluble in water. It is hygroscopic. It decomposes above 300 °C to release oxygen and leaves sodium chloride. Several hundred million tons are produced annually, mainly for applications in bleaching pulp to produce high brightness paper.

<span class="mw-page-title-main">Permanganate</span> Chemical compound

A permanganate is a chemical compound with the manganate(VII) ion, MnO−
4, the conjugate base of permanganic acid. Because the manganese atom has a +7 oxidation state, the permanganate(VII) ion is a strong oxidising agent. The ion is a transition metal ion with a tetrahedral structure. Permanganate solutions are purple in colour and are stable in neutral or slightly alkaline media. The exact chemical reaction depends on the carbon-containing reactants present and the oxidant used. For example, trichloroethane (C2H3Cl3) is oxidised by permanganate ions to form carbon dioxide (CO2), manganese dioxide (MnO2), hydrogen ions (H+), and chloride ions (Cl−).

<span class="mw-page-title-main">Chlorous acid</span> Chemical compound

Chlorous acid is an inorganic compound with the formula HClO2. It is a weak acid. Chlorine has oxidation state +3 in this acid. The pure substance is unstable, disproportionating to hypochlorous acid (Cl oxidation state +1) and chloric acid (Cl oxidation state +5):

<span class="mw-page-title-main">Iodine clock reaction</span> Experiment to show chemical kinetics in action

The iodine clock reaction is a classical chemical clock demonstration experiment to display chemical kinetics in action; it was discovered by Hans Heinrich Landolt in 1886. The iodine clock reaction exists in several variations, which each involve iodine species and redox reagents in the presence of starch. Two colourless solutions are mixed and at first there is no visible reaction. After a short time delay, the liquid suddenly turns to a shade of dark blue due to the formation of a triiodide–starch complex. In some variations, the solution will repeatedly cycle from colorless to blue and back to colorless, until the reagents are depleted.

In chemical nomenclature, the IUPAC nomenclature of inorganic chemistry is a systematic method of naming inorganic chemical compounds, as recommended by the International Union of Pure and Applied Chemistry (IUPAC). It is published in Nomenclature of Inorganic Chemistry. Ideally, every inorganic compound should have a name from which an unambiguous formula can be determined. There is also an IUPAC nomenclature of organic chemistry.

<span class="mw-page-title-main">Barium chlorate</span> Chemical compound

Barium chlorate, Ba(ClO3)2, is the barium salt of chloric acid. It is a white crystalline solid, and like all soluble barium compounds, irritant and toxic. It is sometimes used in pyrotechnics to produce a green color. It also finds use in the production of chloric acid.

<span class="mw-page-title-main">Bleach</span> Chemicals used to whiten or disinfect

Bleach is the generic name for any chemical product that is used industrially or domestically to remove colour (whitening) from fabric or fiber or to disinfect after cleaning. It often refers specifically to a dilute solution of sodium hypochlorite, also called "liquid bleach".

Bleaching of wood pulp is the chemical processing of wood pulp to lighten its color and whiten the pulp. The primary product of wood pulp is paper, for which whiteness is an important characteristic. These processes and chemistry are also applicable to the bleaching of non-wood pulps, such as those made from bamboo or kenaf.

<span class="mw-page-title-main">Miracle Mineral Supplement</span> Industrial bleach illegally marketed as a cure for various illnesses

Miracle Mineral Supplement, often referred to as Miracle Mineral Solution, Master Mineral Solution, MMS or the CD protocol, is a branded name for an aqueous solution of chlorine dioxide, an industrial bleaching agent, that has been falsely promoted as a cure for illnesses including HIV, cancer and the common cold. It is made by mixing aqueous sodium chlorite with an acid. This produces chlorine dioxide, a toxic chemical that can cause nausea, vomiting, diarrhea, and life-threatening low blood pressure due to dehydration.

<span class="mw-page-title-main">Water chlorination</span> Chorination of water

Water chlorination is the process of adding chlorine or chlorine compounds such as sodium hypochlorite to water. This method is used to kill bacteria, viruses and other microbes in water. In particular, chlorination is used to prevent the spread of waterborne diseases such as cholera, dysentery, and typhoid.

Potassium hypochlorite is the potassium salt of hypochlorous acid. It is used in variable concentrations, often diluted in water solution. It has a light grey color and a strong chlorine smell. It can be used as a disinfectant.

<span class="mw-page-title-main">Chlorine-releasing compounds</span>

Chlorine-releasing compounds, also known as chlorine base compounds, is jargon to describe certain chlorine-containing substances that are used as disinfectants and bleaches. They include the following chemicals: sodium hypochlorite, chloramine, halazone, and sodium dichloroisocyanurate. They are widely used to disinfect water and medical equipment, and surface areas as well as bleaching materials such as cloth. The presence of organic matter can make them less effective as disinfectants. They come as a liquid solution, or as a powder that is mixed with water before use.

Silver chlorite is a chemical compound with the formula AgClO2. This slightly yellow solid is shock sensitive and has an orthorhombic crystal structure.

References

  1. 1 2 EPA Guidance Manual, chapter 4: Chlorine dioxide (PDF), US Environmental Protection Agency, archived (PDF) from the original on 2008-10-11, retrieved 2012-02-27
  2. ↑ "Chlorine dioxide" (PDF). Archived (PDF) from the original on 2012-03-30. Retrieved 2011-11-02.
  3. ↑ "CFR - Code of Federal Regulations Title 21". www.accessdata.fda.gov. Retrieved 2021-11-18.
  4. ↑ Cohen J (2008-05-13). "New mouthwashes may help take bad breath away". USA Today . Archived from the original on 2012-06-26.
  5. ↑ "SmartMouth 2 Step Mouth Rinse". dentist.net. Archived from the original on 29 October 2010. Retrieved 26 April 2018.
  6. ↑ Blink Tears
  7. ↑ Bal BS, Childers WE, Pinnick HW (1981). "Oxidation of α,β-unsaturated aldehydes". Tetrahedron (abstract). 37 (11): 2091–2096. doi:10.1016/S0040-4020(01)97963-3.
  8. ↑ Annangudi SP, Sun M, Salomon RG (2005). "An efficient synthesis of 4-oxo-2-alkenoic acids from 2-alkyl furans". Synlett (abstract). 9 (9): 1468–1470. doi:10.1055/s-2005-869833.
  9. ↑ Acidified sodium chlorite handling/processing (PDF), Agricultural Marketing Service (USDA), July 21, 2008, archived from the original on April 8, 2013, retrieved December 9, 2012
  10. ↑ Rao MV (2007), Acidified sodium chlorite (ACS), chemical and technical assessment (PDF), Food and Agricultural Organization of the United Nations, archived (PDF) from the original on December 3, 2012, retrieved December 9, 2012
  11. ↑ Hillerton J, Cooper J, Morelli J (2007). "Preventing Bovine Mastitis by a Postmilking Teat Disinfectant Containing Acidified Sodium Chlorite". Journal of Dairy Science . 90 (3): 1201–1208. doi: 10.3168/jds.S0022-0302(07)71607-7 . PMID   17297095.
  12. ↑ Natick plays key role in helping to fight spread of Ebola Archived 2015-06-24 at the Wayback Machine Retrieved: 23/01/2016
  13. ↑ US EPA O (2020-03-13). "List N: Disinfectants for Use Against SARS-CoV-2". US EPA. Retrieved 2020-03-28.
  14. ↑ "How we know disinfectants should kill the COVID-19 coronavirus". Chemical & Engineering News. Retrieved 2020-03-31.
  15. ↑ Taylor MC (1940). "Sodium Chlorite Properties and Reactions". Industrial & Engineering Chemistry. 32 (7): 899–903. doi:10.1021/ie50367a007. S2CID   96222235.
  16. ↑ Goldfrank's Toxicologic Emergencies, McGraw-Hill Professional; 8th edition (March 28, 2006), ISBN   978-0-07-143763-9
  17. ↑ "Chlorates". PoisonCentre.be (in French). Archived from the original on 2012-12-11. Retrieved 2012-12-11.
  18. ↑ Clinical Toxicology of Commercial Products. Robert E. Gosselin, Roger P. Smith, Harold C. Hodge, Jeannet Braddock. Uitgever: Williams & Wilkins; 5 edition (September 1984) ISBN   978-0-683-03632-9
  19. ↑ "Sodium Chlorite — Summary Report" (PDF). European Agency for the Evaluation of Medicinal Products — Veterinary Medicines Evaluation Unit. Archived from the original (PDF) on 2007-07-10. Retrieved 2007-07-10.
  20. ↑ Lin JL, Lim PS (1993). "Acute sodium chlorite poisoning associated with renal failure". Ren Fail. 15 (5): 645–8. doi:10.3109/08860229309069417. PMID   8290712.
  21. ↑ "ATSDR: ToxFAQs for Chlorine Dioxide and Chlorite". Archived from the original on 2012-07-02.
  22. ↑ "Seller of "Miracle Mineral Solution" Convicted for Marketing Toxic Chemical as a Miracle Cure". United States Department of Justice. 28 May 2015. Archived from the original on May 11, 2016. Retrieved May 11, 2016.
  23. ↑ "Assurance of Voluntary Compliance - Kerri Rivera" (PDF). NBC Chicago . Archived (PDF) from the original on 4 April 2016. Retrieved 24 September 2016.
  24. ↑ Australian Competition and Consumer Commission v Leanne Rita Vassallo and Aaron David Smith(FCA 954August 20, 2009), Text .
  25. ↑ Pulkkinen L (August 3, 2009). "Sexy stories, bogus cures lead to action by state AG". SeattlePI.com . seattlepi.com staff. OCLC   3734418. Archived from the original on November 2, 2013. Retrieved February 12, 2012.
  26. ↑ "Washington Attorney General reels in refunds for consumers hooked by Aussies' quack medicine web sites" (Press release). Washington State Office of the Attorney General. March 8, 2010. Archived from the original on December 7, 2011. Retrieved February 12, 2012.
  27. ↑ "Aussie net scammers stung after $1.2m haul". ITnews for Australian Business. Haymarket Media. Aug 26, 2009. Archived from the original on September 20, 2011. Retrieved February 12, 2012.
  28. ↑ "Woman told to stop selling cancer 'miracle drug'". ABC News. Australia. April 23, 2009. Archived from the original on June 14, 2013. Retrieved February 12, 2012.
  29. ↑ "Unregistered health provider ordered to stop misleading cancer patients" (Press release). Minister for Tourism and Fair Trading, The Honourable Peter Lawlor. April 23, 2009. Archived from the original on April 3, 2011. Retrieved February 12, 2012.
  30. ↑ Mole B (2019-08-14). "People are still drinking bleach—and vomiting and pooping their guts out". Ars Technica. Retrieved 2019-08-15.
  31. ↑ Qian Y, Chen Y, Jiang Y, Zhang L (2007). "A clean production process of sodium chlorite from sodium chlorate". Journal of Cleaner Production. 15 (10): 920–926. doi:10.1016/j.jclepro.2004.07.008.
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