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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]
CAS No.: 7758-19-2
EC No.: 231-836-6
Synonyms:
SODIUM CHLORITE; SODYUM KLORİT; sodium chlorite; sodyum klorit; SODIUM CHLORITE; 7758-19-2; Chlorous acid, sodium salt; Textone; Chlorite sodium; Textile; Alcide LD; Neo Silox D; Caswell No. 755; sodiumchlorite; UNII-G538EBV4VF; NaClO2; CCRIS 1426; HSDB 733; Chlorous acid, sodium salt (1:1); EINECS 231-836-6; UN1496; EPA Pesticide Chemical Code 020502; G538EBV4VF; SODIUM CHLORITE; SODYUM KLORİT; sodium chlorite; sodyum klorit; SODIUM CHLORITE; SODYUM KLORİT; sodium chlorite; sodyum klorit; CHEBI:78667; Sodium chlorite (water disinfection byproducts); Sodium chlorite, 80%, pure, unstabilized; Chlorite (sodium salt); NaO2Cl; ClO2.Na; DSSTox_CID_1272; EC 231-836-6; DSSTox_RID_76050; SODIUM CHLORITE; SODYUM KLORİT; sodium chlorite; sodyum klorit; SODIUM CHLORITE; SODYUM KLORİT; sodium chlorite; sodyum klorit; DSSTox_GSID_21272; KSC377K5L; CHEMBL1887585; DTXSID8021272; CTK2H7555; KS-00000VDV; Tox21_302800; 8421AF; ANW-37060; AKOS015843819; DB13210; LS-1723; Sodium chlorite [UN1496] [Oxidizer]; NCGC00091419-01; NCGC00256359-01; Sodium chlorite [UN1496] [Oxidizer]; SC-22967; SODIUM CHLORITE; SODYUM KLORİT; sodium chlorite; sodyum klorit; SODIUM CHLORITE; SODYUM KLORİT; sodium chlorite; sodyum klorit; CAS-7758-19-2; FT-0695293; C19523; Q411294; WATER DISINFECTION BYPRODUCTS(SODIUM CHLORITE); SodiuM chlorite, unstabilized, pure, 80% 500GR; Scentrex? DTS 1.05 sachet; Sodium chlorite puriss. p.a., 80% (RT); Sodium chlorite technical grade, 80%; Sodium chlorite, technical, 80%; SODIUM CHLORITE; SODYUM KLORİT; sodium chlorite; sodyum klorit; SODIUM CHLORITE; SODYUM KLORİT; sodium chlorite; sodyum klorit; Sodium chlorite, Unstabilized; Sodium Chlorite, Anhydrous; textile; CHLORINE DIOXIDE RELEASE MIXTURE; CHLORITE; CHLORITE ION; SCENTREX(TM) DTS 7.05 SACHET; SODIUM CHLORITE; TEXTONE; alcideld; chloritedesodium; chloritesolution; Chlorousacid,sodiumsalt; Chlorousacidsodiumsalt; neosiloxd; sodiumchlorite(sourceofchlorinedioxide); SODIUM CHLORITE; SODYUM KLORİT; sodium chlorite; sodyum klorit; SODIUM CHLORITE; SODYUM KLORİT; SODIUM CHLORITE; SODYUM KLORİT; sodium chlorite; sodyum klorit; SODIUM CHLORITE; SODYUM KLORİT; sodium chlorite; sodyum klorit; sodium chlorite; sodyum klorit; textile; (SODIUM CHLORITE)80 PCT; SODIUM CHLORITE, TECH., 80%; CHLORINE DIOXIDE RELEASE MIXTURE, SCENTR; CHLORINE DIOXIDE RELEASE MIXTURE, ASEPTR OL(TM) WTS 7.05 SACHET; Sodium Chlorite (Solid); Sodium Chlorite (Aqueous Solution); chlorite sodium; chlorous acid sodium salt (1:1); chlorous acid, sodium salt; chlorous acid, sodium salt (1:1); sodium chlorite [UN1496] [Oxidizer]; SODIUM CHLORITE; SODYUM KLORİT; sodium chlorite; sodyum klorit; SODIUM CHLORITE; SODYUM KLORİT; sodium chlorite; sodyum klorit; SODIUM CHLORITE; 7758-19-2; Chlorous acid, sodium salt; Textone; Chlorite sodium; Textile; Alcide LD; Neo Silox D; Caswell No. 755; sodiumchlorite; UNII-G538EBV4VF; NaClO2; CCRIS 1426; HSDB 733; Chlorous acid, sodium salt (1:1); EINECS 231-836-6; UN1496; EPA Pesticide Chemical Code 020502; G538EBV4VF; SODIUM CHLORITE; SODYUM KLORİT; sodium chlorite; sodyum klorit; SODIUM CHLORITE; SODYUM KLORİT; sodium chlorite; sodyum klorit; CHEBI:78667; Sodium chlorite (water disinfection byproducts); Sodium chlorite, 80%, pure, unstabilized; Chlorite (sodium salt); NaO2Cl; ClO2.Na; DSSTox_CID_1272; EC 231-836-6; DSSTox_RID_76050; SODIUM CHLORITE; SODYUM KLORİT; sodium chlorite; sodyum klorit; SODIUM CHLORITE; SODYUM KLORİT; sodium chlorite; sodyum klorit; DSSTox_GSID_21272; KSC377K5L; CHEMBL1887585; DTXSID8021272; CTK2H7555; KS-00000VDV; Tox21_302800; 8421AF; ANW-37060; AKOS015843819; DB13210; LS-1723; Sodium chlorite [UN1496] [Oxidizer]; NCGC00091419-01; NCGC00256359-01; Sodium chlorite [UN1496] [Oxidizer]; SC-22967; SODIUM CHLORITE; SODYUM KLORİT; sodium chlorite; sodyum klorit; SODIUM CHLORITE; SODYUM KLORİT; sodium chlorite; sodyum klorit; CAS-7758-19-2; FT-0695293; C19523; Q411294; WATER DISINFECTION BYPRODUCTS(SODIUM CHLORITE); SodiuM chlorite, unstabilized, pure, 80% 500GR; Scentrex? DTS 1.05 sachet; Sodium chlorite puriss. p.a., 80% (RT); Sodium chlorite technical grade, 80%; Sodium chlorite, technical, 80%; SODIUM CHLORITE; SODYUM KLORİT; sodium chlorite; sodyum klorit; SODIUM CHLORITE; SODYUM KLORİT; sodium chlorite; sodyum klorit; Sodium chlorite, Unstabilized; Sodium Chlorite, Anhydrous; textile; CHLORINE DIOXIDE RELEASE MIXTURE; CHLORITE; CHLORITE ION; SCENTREX(TM) DTS 7.05 SACHET; SODIUM CHLORITE; TEXTONE; alcideld; chloritedesodium; chloritesolution; Chlorousacid,sodiumsalt; Chlorousacidsodiumsalt; neosiloxd; sodiumchlorite(sourceofchlorinedioxide); SODIUM CHLORITE; SODYUM KLORİT; sodium chlorite; sodyum klorit; SODIUM CHLORITE; SODYUM KLORİT; SODIUM CHLORITE; SODYUM KLORİT; sodium chlorite; sodyum klorit; SODIUM CHLORITE; SODYUM KLORİT; sodium chlorite; sodyum klorit; sodium chlorite; sodyum klorit; textile; (SODIUM CHLORITE)80 PCT; SODIUM CHLORITE, TECH., 80%; CHLORINE DIOXIDE RELEASE MIXTURE, SCENTR; CHLORINE DIOXIDE RELEASE MIXTURE, ASEPTR OL(TM) WTS 7.05 SACHET; Sodium Chlorite (Solid); Sodium Chlorite (Aqueous Solution); chlorite sodium; chlorous acid sodium salt (1:1); chlorous acid, sodium salt; chlorous acid, sodium salt (1:1); sodium chlorite [UN1496] [Oxidizer]; SODIUM CHLORITE; SODYUM KLORİT; sodium chlorite; sodyum klorit
SODIUM CHLORITE
Sodium chlorite
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Sodium chlorite
Na+.svg
Chlorition.png
The sodium cation
Space-filling model of the chlorite anion
Sodium chlorite 450g.jpg
Names
IUPAC name
Sodium chlorite
Other names
Chlorous acid, sodium salt
Textone
Identifiers
CAS Number
7758-19-2 check
49658-21-1 (trihydrate) ☒
3D model (JSmol)
Interactive image
ChEBI
CHEBI:78667 ☒
ChemSpider
22860 check
ECHA InfoCard 100.028.942 Edit this at Wikidata
EC Number
231-836-6
KEGG
C19523 ☒
PubChem CID
23668197
RTECS number
VZ4800000
UNII
G538EBV4VF check
UN number 1496
CompTox Dashboard (EPA)
DTXSID8021272 Edit this at Wikidata
InChI[show]
SMILES[show]
Properties
Chemical formula NaClO2
Molar mass 90.442 g/mol (anhydrous)
144.487 g/mol (trihydrate)
Appearance white solid
Odor odorless
Density 2.468 g/cm3, solid
Melting point anhydrous decomposes at 180–200 °C
trihydrate decomposes at 38 °C
Solubility in water 75.8 g/100 mL (25 °C)
122 g/100 mL (60 °C)
Solubility slightly soluble in methanol, ethanol
Acidity (pKa) 10-11
Structure
Crystal structure monoclinic
Thermochemistry
Std enthalpy of
formation (ΔfH⦵298) -307.0 kJ/mol
Pharmacology
ATC code D03AX11 (WHO)
Hazards
Safety data sheet SDS
GHS pictograms GHS03: OxidizingGHS05: CorrosiveGHS06: ToxicGHS09: Environmental hazard
GHS Signal word Danger
GHS hazard statements H272, H301, H310, H330, H314, H318, H400
GHS precautionary statements P210, P220, P221, P260, P262, P264, P270, P271, P273, P280, P284, P301+330+331, P303+361+353, P305+351+338, P310, P361, P363, P370+378, P391, P403+233, P405, P501
Ingestion hazard Category 3
Inhalation hazard Category 2
Eye hazard Category 1
Skin hazard Category 1B
NFPA 704 (fire diamond)
NFPA 704 four-colored diamond
021OX
Flash point Non-flammable
Lethal dose or concentration (LD, LC):
LD50 (median dose) 350 mg/kg (rat, oral)
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).
☒ verify (what is check☒ ?)
Infobox references
Sodium chlorite (NaClO2) is a chemical compound used in the manufacturing of paper and as a disinfectant.
Contents
1 Use
1.1 Chemical reagent
1.2 Acidified sodium chlorite
1.3 Use in public crises
2 Safety
3 Toxicity
4 Manufacture
5 General references
6 References
7 External links
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]
Sodium chlorite, NaClO2, sometimes in combination with zinc chloride, also finds application as a component in therapeutic rinses, mouthwashes,[3][4] toothpastes and gels, mouth sprays, as preservative in eye drops,[5] 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).[6]
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.[7]
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.[8][9] ASC also is used as a teat dip for control of mastitis in dairy cattle.[10]
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.[11]
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.[12][13] 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.[14] 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.[15] A dose of 10-15 grams of sodium chlorate can be lethal.[16] Methemoglobemia had been demonstrated in rats and cats,[17] 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.[18]
There is only one human case in the medical literature of chlorite poisoning.[19] 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.[20]
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.[21] [22] [23][24] [25][26] [27][28][29]
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.[30]
Sodium Chlorite: Can It Be Used as Medicine?
Chlorite vs. chloride
Typical uses
Health claims
Alleged medical uses
Safety and side effects
Takeaway
What’s sodium chlorite?
Sodium chlorite — also referred to as chlorous acid, sodium salt textone, and Miracle Mineral Solution — is composed of sodium (Na), chlorine (Cl), and oxygen (O2).
Many claims have been made for its use as a health supplement. However, the U.S. Food and Drug Administration (FDA)Trusted Source warns that it’s a dangerous, potentially life threatening chemical that should never be swallowed.
It isn’t the same as sodium chloride
Don’t confuse sodium chlorite with sodium chloride.
Sodium chloride (NaCl) is also called table salt. Sodium chloride is used for many things, but it’s typically thought of as a seasoning and food preservative. Sodium chlorite (NaClO2) is typically found in an industrial setting as a bleach and a disinfectant.
How’s sodium chlorite used?
Sodium chlorite is marketed to both consumers and industries for various uses.
Some consumer uses of sodium chlorite include:
water treatment and purification
surface cleaner for areas of food preparation
antimicrobial treatment for food, especially seafood
Larger concentrations of sodium chlorite are commonly used for industrial purposes, such as:
bleaching and stripping of textiles, pulp, and paper
sterilizing agent used in water treatment plants
Are there any health benefits to sodium chlorite?
Sodium chlorite has been promoted as a health supplement and a treatment for various illnesses, such as:
common cold
arthritis
HIV
malaria
cancer
hepatitis
amyotrophic lateral sclerosis (ALS)
While there are anecdotal reports from people who claim to have experienced medical relief by ingesting sodium chlorite solutions, there’s no reliable scientific evidence showing a benefit.
The FDA issued a warning in 2019 to not drink sodium chlorite products, stating they are dangerous.Trusted Source
Promoted health benefits
Despite the lack of evidence supporting the use of sodium chlorite as a medication, some continue to support this chemical as a form of alternative medicine.
Of these supporters, people with ALS — also known as Lou Gehrig’s disease — report the most positive benefits from sodium chlorite.
ALS is a rare neurological disease that progressively leads to:
muscle weakness
impaired motor function
muscle cramps
slurred speech
Eventually this condition can shut down vital parts of the body. Only about 10 percent of people with this condition live for longer than 10 years following diagnosis.
People with ALS who use sodium chlorite report positive benefits, including:
increased muscle activity
clearer speech
slowed rate of ALS progression
improved flexibility
improved motor functions, balance, and speed of movement
Sodium chlorite received approval in the European Union as an “orphan drug” in the treatment of ALS. These drugs are usually used for rare conditions and don’t always require proven safety and effectiveness.
A small number of studies have evaluated sodium chlorite in people with ALS, but the results are too preliminary to know if it’s beneficial.
Is it safe to ingest sodium chlorite?
Ingesting sodium chlorite as a form of alternative medicine for extended periods of time or in larger dosages is unsafe and can cause a variety of symptoms, including:
fatigue
diarrhea
headache
nausea
excess saliva
insomnia
dehydration
lowered blood pressure
In addition to these symptoms, there are more serious health problems that healthcare providers warn may result from use of this chemical, such as:
worsening of ALS
skin burns
nosebleeds
hoarse throat
coughing
bronchitis
shortness of breath
In high concentrations, sodium chlorite is typically used as a bleach and a disinfectant.
Sodium chlorite can be supplied either as a solid or a solution. Both forms are potentially dangerous and require a high degree of safety and skill during storage and handling. Sodium chlorite is a white flaky salt prepared at a concentration of 80%. It is extremely reactive and will explode in a violent reaction on contact with organic substances including basic items such as gloves and clothing, spillage control materials such as sawdust and cotton waste, or even oil and grease. Heat, friction or just impact can lead to an explosion, so the solid should be dissolved in water to form a solution as quickly as possible. In practice the dry form is simply too dangerous to transport, store and handle for normal WTP use, so liquid sodium chlorite is normally employed.
Sodium chlorite is a highly corrosive liquid that requires careful handling to avoid damage to pipe work and equipment. Spillages of sodium chlorite must be washed away before they evaporate to leave the flammable dry residue. It has to be stored under temperature controlled conditions and is supplied at a concentration of 25–26% w/w, which gives the sodium chlorite optimum storage characteristics. At this concentration it still freezes at −15°C and is also explosive at relatively low temperatures and so should be maintained at below 40°C (Cowley, 1993). The solution is stable under neutral to slightly acidic conditions but will decay under more acidic conditions which can be prevented by adding a small amount of alkalinity (<10 mg CaCO3 L−1). However, it will also decay if the alkalinity buffers the solution above pH 8.0 (Eq. 32.6), so pH control during storage is an important consideration. Chlorate is present as an impurity in most sodium chlorite products with contamination levels usually 2–3% by weight of chlorite.
[32.6]
Chlorine dioxide has a relatively short half life and so is made up as required at a concentration of 1g L−1 if used in open systems or 10 g L−1 if used in enclosed pressurized systems. It is produced by reacting chlorine gas or a solution of chlorine with sodium chlorite in a glass mixing chamber which is filled with porcelain Raschig rings or Teflon® chips (Eq. 32.5). Stoichiometrically 0.5 kg of Cl2 and 1.34 kg NaClO2 are required to produce 1 kg of ClO2 (Fig. 32.1; Black and Veatch Corporation, 2010). Once prepared, ClO2 can be photo-chemically degraded in sunlight to form chlorate, chlorite, hydrogen peroxide, oxygen and chlorine, and so it must be stored and used in the dark. Similarly it is destroyed by UV light.
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Figure 32.1. Schematic diagram of the generation and use of chlorine dioxide using chlorine gas.
Alternatively chlorine dioxide can be produced by reacting the sodium chlorite with hydrochloric acid. However, this process uses 1.25 times more NaClO2 than the chlorine reaction to produce the same weight of ClO2 (Eq. 32.7). Stoichiometrically 0.54 kg of HCl and 1.67 kg NaClO2 are required to produce 1 kg of ClO2, although in practice 50% more NaClO2 is required and possibly up to three times the amount of HCl may be needed to lower the pH sufficiently for the reaction to occur at pH ≤0.5 (Twort et al., 2000).
[32.7]
Generators are normally rented so when this is added to the cost of sodium chlorite, then chlorine dioxide disinfection is expensive, even taking into consideration that smaller doses are required compared to either chlorine or chloramines. Contact tank designs and the use of either injectors or diffusers are very similar to those used for chlorination (see Ch. 31, p. 580). However, care must be taken not to allow chlorine dioxide to escape to the atmosphere, so open pipes or channels should not be used at high ClO2 concentrations. Further details on the generation and use of chlorine dioxide are given in Gates (1998).
General description
The acidified solution of sodium chlorite has been tested for the antimicrobial action on the broiler carcasses. It was found to be effective in the reduction of natural bioburden in a prechill procedure..[3]
Application
Sodium chlorite may be used in the synthesis of chlorine dioxide[1] and as a hydroxylating agent for the hydroxylation of androstenedione (steroid).[2]
Sodium chlorite
Jump to navigationJump to search
Sodium chlorite
Na+.svg
Chlorition.png
The sodium cation
Space-filling model of the chlorite anion
Sodium chlorite 450g.jpg
Names
IUPAC name
Sodium chlorite
Other names
Chlorous acid, sodium salt
Textone
Identifiers
CAS Number
7758-19-2 check
49658-21-1 (trihydrate) ☒
3D model (JSmol)
Interactive image
ChEBI
CHEBI:78667 ☒
ChemSpider
22860 check
ECHA InfoCard 100.028.942 Edit this at Wikidata
EC Number
231-836-6
KEGG
C19523 ☒
PubChem CID
23668197
RTECS number
VZ4800000
UNII
G538EBV4VF check
UN number 1496
CompTox Dashboard (EPA)
DTXSID8021272 Edit this at Wikidata
InChI[show]
SMILES[show]
Properties
Chemical formula NaClO2
Molar mass 90.442 g/mol (anhydrous)
144.487 g/mol (trihydrate)
Appearance white solid
Odor odorless
Density 2.468 g/cm3, solid
Melting point anhydrous decomposes at 180–200 °C
trihydrate decomposes at 38 °C
Solubility in water 75.8 g/100 mL (25 °C)
122 g/100 mL (60 °C)
Solubility slightly soluble in methanol, ethanol
Acidity (pKa) 10-11
Structure
Crystal structure monoclinic
Thermochemistry
Std enthalpy of
formation (ΔfH⦵298) -307.0 kJ/mol
Pharmacology
ATC code D03AX11 (WHO)
Hazards
Safety data sheet SDS
GHS pictograms GHS03: OxidizingGHS05: CorrosiveGHS06: ToxicGHS09: Environmental hazard
GHS Signal word Danger
GHS hazard statements H272, H301, H310, H330, H314, H318, H400
GHS precautionary statements P210, P220, P221, P260, P262, P264, P270, P271, P273, P280, P284, P301+330+331, P303+361+353, P305+351+338, P310, P361, P363, P370+378, P391, P403+233, P405, P501
Ingestion hazard Category 3
Inhalation hazard Category 2
Eye hazard Category 1
Skin hazard Category 1B
NFPA 704 (fire diamond)
NFPA 704 four-colored diamond
021OX
Flash point Non-flammable
Lethal dose or concentration (LD, LC):
LD50 (median dose) 350 mg/kg (rat, oral)
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).
☒ verify (what is check☒ ?)
Infobox references
Sodium chlorite (NaClO2) is a chemical compound used in the manufacturing of paper and as a disinfectant.
Contents
1 Use
1.1 Chemical reagent
1.2 Acidified sodium chlorite
1.3 Use in public crises
2 Safety
3 Toxicity
4 Manufacture
5 General references
6 References
7 External links
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]
Sodium chlorite, NaClO2, sometimes in combination with zinc chloride, also finds application as a component in therapeutic rinses, mouthwashes,[3][4] toothpastes and gels, mouth sprays, as preservative in eye drops,[5] 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).[6]
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.[7]
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.[8][9] ASC also is used as a teat dip for control of mastitis in dairy cattle.[10]
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.[11]
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.[12][13] 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.[14] 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.[15] A dose of 10-15 grams of sodium chlorate can be lethal.[16] Methemoglobemia had been demonstrated in rats and cats,[17] 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.[18]
There is only one human case in the medical literature of chlorite poisoning.[19] 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.[20]
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.[21] [22] [23][24] [25][26] [27][28][29]
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.[30]
Sodium Chlorite: Can It Be Used as Medicine?
Chlorite vs. chloride
Typical uses
Health claims
Alleged medical uses
Safety and side effects
Takeaway
What’s sodium chlorite?
Sodium chlorite — also referred to as chlorous acid, sodium salt textone, and Miracle Mineral Solution — is composed of sodium (Na), chlorine (Cl), and oxygen (O2).
Many claims have been made for its use as a health supplement. However, the U.S. Food and Drug Administration (FDA)Trusted Source warns that it’s a dangerous, potentially life threatening chemical that should never be swallowed.
It isn’t the same as sodium chloride
Don’t confuse sodium chlorite with sodium chloride.
Sodium chloride (NaCl) is also called table salt. Sodium chloride is used for many things, but it’s typically thought of as a seasoning and food preservative. Sodium chlorite (NaClO2) is typically found in an industrial setting as a bleach and a disinfectant.
How’s sodium chlorite used?
Sodium chlorite is marketed to both consumers and industries for various uses.
Some consumer uses of sodium chlorite include:
water treatment and purification
surface cleaner for areas of food preparation
antimicrobial treatment for food, especially seafood
Larger concentrations of sodium chlorite are commonly used for industrial purposes, such as:
bleaching and stripping of textiles, pulp, and paper
sterilizing agent used in water treatment plants
Are there any health benefits to sodium chlorite?
Sodium chlorite has been promoted as a health supplement and a treatment for various illnesses, such as:
common cold
arthritis
HIV
malaria
cancer
hepatitis
amyotrophic lateral sclerosis (ALS)
While there are anecdotal reports from people who claim to have experienced medical relief by ingesting sodium chlorite solutions, there’s no reliable scientific evidence showing a benefit.
The FDA issued a warning in 2019 to not drink sodium chlorite products, stating they are dangerous.Trusted Source
Promoted health benefits
Despite the lack of evidence supporting the use of sodium chlorite as a medication, some continue to support this chemical as a form of alternative medicine.
Of these supporters, people with ALS — also known as Lou Gehrig’s disease — report the most positive benefits from sodium chlorite.
ALS is a rare neurological disease that progressively leads to:
muscle weakness
impaired motor function
muscle cramps
slurred speech
Eventually this condition can shut down vital parts of the body. Only about 10 percent of people with this condition live for longer than 10 years following diagnosis.
People with ALS who use sodium chlorite report positive benefits, including:
increased muscle activity
clearer speech
slowed rate of ALS progression
improved flexibility
improved motor functions, balance, and speed of movement
Sodium chlorite received approval in the European Union as an “orphan drug” in the treatment of ALS. These drugs are usually used for rare conditions and don’t always require proven safety and effectiveness.
A small number of studies have evaluated sodium chlorite in people with ALS, but the results are too preliminary to know if it’s beneficial.
Is it safe to ingest sodium chlorite?
Ingesting sodium chlorite as a form of alternative medicine for extended periods of time or in larger dosages is unsafe and can cause a variety of symptoms, including:
fatigue
diarrhea
headache
nausea
excess saliva
insomnia
dehydration
lowered blood pressure
In addition to these symptoms, there are more serious health problems that healthcare providers warn may result from use of this chemical, such as:
worsening of ALS
skin burns
nosebleeds
hoarse throat
coughing
bronchitis
shortness of breath
In high concentrations, sodium chlorite is typically used as a bleach and a disinfectant.
Sodium chlorite can be supplied either as a solid or a solution. Both forms are potentially dangerous and require a high degree of safety and skill during storage and handling. Sodium chlorite is a white flaky salt prepared at a concentration of 80%. It is extremely reactive and will explode in a violent reaction on contact with organic substances including basic items such as gloves and clothing, spillage control materials such as sawdust and cotton waste, or even oil and grease. Heat, friction or just impact can lead to an explosion, so the solid should be dissolved in water to form a solution as quickly as possible. In practice the dry form is simply too dangerous to transport, store and handle for normal WTP use, so liquid sodium chlorite is normally employed.
Sodium chlorite is a highly corrosive liquid that requires careful handling to avoid damage to pipe work and equipment. Spillages of sodium chlorite must be washed away before they evaporate to leave the flammable dry residue. It has to be stored under temperature controlled conditions and is supplied at a concentration of 25–26% w/w, which gives the sodium chlorite optimum storage characteristics. At this concentration it still freezes at −15°C and is also explosive at relatively low temperatures and so should be maintained at below 40°C (Cowley, 1993). The solution is stable under neutral to slightly acidic conditions but will decay under more acidic conditions which can be prevented by adding a small amount of alkalinity (<10 mg CaCO3 L−1). However, it will also decay if the alkalinity buffers the solution above pH 8.0 (Eq. 32.6), so pH control during storage is an important consideration. Chlorate is present as an impurity in most sodium chlorite products with contamination levels usually 2–3% by weight of chlorite.
[32.6]
Chlorine dioxide has a relatively short half life and so is made up as required at a concentration of 1g L−1 if used in open systems or 10 g L−1 if used in enclosed pressurized systems. It is produced by reacting chlorine gas or a solution of chlorine with sodium chlorite in a glass mixing chamber which is filled with porcelain Raschig rings or Teflon® chips (Eq. 32.5). Stoichiometrically 0.5 kg of Cl2 and 1.34 kg NaClO2 are required to produce 1 kg of ClO2 (Fig. 32.1; Black and Veatch Corporation, 2010). Once prepared, ClO2 can be photo-chemically degraded in sunlight to form chlorate, chlorite, hydrogen peroxide, oxygen and chlorine, and so it must be stored and used in the dark. Similarly it is destroyed by UV light.
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Figure 32.1. Schematic diagram of the generation and use of chlorine dioxide using chlorine gas.
Alternatively chlorine dioxide can be produced by reacting the sodium chlorite with hydrochloric acid. However, this process uses 1.25 times more NaClO2 than the chlorine reaction to produce the same weight of ClO2 (Eq. 32.7). Stoichiometrically 0.54 kg of HCl and 1.67 kg NaClO2 are required to produce 1 kg of ClO2, although in practice 50% more NaClO2 is required and possibly up to three times the amount of HCl may be needed to lower the pH sufficiently for the reaction to occur at pH ≤0.5 (Twort et al., 2000).
[32.7]
Generators are normally rented so when this is added to the cost of sodium chlorite, then chlorine dioxide disinfection is expensive, even taking into consideration that smaller doses are required compared to either chlorine or chloramines. Contact tank designs and the use of either injectors or diffusers are very similar to those used for chlorination (see Ch. 31, p. 580). However, care must be taken not to allow chlorine dioxide to escape to the atmosphere, so open pipes or channels should not be used at high ClO2 concentrations. Further details on the generation and use of chlorine dioxide are given in Gates (1998).
General description
The acidified solution of sodium chlorite has been tested for the antimicrobial action on the broiler carcasses. It was found to be effective in the reduction of natural bioburden in a prechill procedure..[3]
Application
Sodium chlorite may be used in the synthesis of chlorine dioxide[1] and as a hydroxylating agent for the hydroxylation of androstenedione (steroid).[2]
