Sodium chlorite
Encyclopedia
Sodium chlorite is a chemical compound used in the manufacture of paper
.
. An advantage in this application, as compared to the more commonly used chlorine, is that trihalomethane
s (such as chloroform
) are not produced from organic contaminants. . Chlorine dioxide generated from sodium chlorite is approved by FDA under some conditions for disinfecting water used to wash fruits, vegetables, and poultry.
Sodium chlorite, NaClO2, sometimes in combination with zinc chloride
, also finds application as a component in therapeutic rinses, mouthwashes, toothpastes and gels, mouth sprays, as a teat dip for control of mastitis in dairy cattle
, as preservative in eye drops, and in contact lens cleaning solution under the trade name Purite.
Under the brand name Oxine it is used for sanitizing air ducts and HVAC/R systems and animal containment areas (walls, floors, and other surfaces).
, sodium chlorite is frequently used as a reagent in the Pinnick oxidation
for the oxidation of aldehyde
s to carboxylic acid
s. The reaction is usually performed in monosodium phosphate
buffered solution in the presence of a chlorine scavenger (usually 2-methyl-2-butene
).
Recently, sodium chlorite has been used as an oxidizing agent to convert alkyl furans to the corresponding 4-oxo-2-alkenoic acids in a simple one pot synthesis.
s, should be protected from inadvertent contamination by organic materials to avoid the formation of an explosive mixture. The chemical explodes on percussive impact, and will ignite if combined with a strong antioxidant
(reducing agent).
: methemoglobinemia
, hemolysis
, renal failure
. A dose of 10-15 grams of sodium chlorate
can be lethal. Methemoglobemia had been demonstrated in rats and cats and recent studies by the EMEA
have confirmed that the clinical symptomatology is very similar to the one caused by sodium chlorate
in the rat, mouse, rabbit, and the green monkey.
There is only one human case in the medical literature of chlorite
poisoning. 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.
, 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, the explosive (only at concentrations greater than 10% in atmosphere) chlorine dioxide
, ClO2 is produced by reducing sodium chlorate in a strong acid solution with a suitable reducing agent (for example, sodium sulfite
, sulfur dioxide
, or hydrochloric acid
). The chlorine dioxide
is then absorbed into an alkaline solution and reduced with hydrogen peroxide
, yielding sodium chlorite.
.
Paper
Paper is a thin material mainly used for writing upon, printing upon, drawing or for packaging. It is produced by pressing together moist fibers, typically cellulose pulp derived from wood, rags or grasses, and drying them into flexible sheets....
.
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 a few municipal water treatment plants after conversion to chlorine dioxideChlorine dioxide
Chlorine dioxide is a chemical compound with the formula ClO2. This yellowish-green gas crystallizes as bright orange crystals at −59 °C. As one of several oxides of chlorine, it is a potent and useful oxidizing agent used in water treatment and in bleaching....
. An advantage in this application, as compared to the more commonly used chlorine, is that trihalomethane
Trihalomethane
Trihalomethanes are chemical compounds in which three of the four hydrogen atoms of methane are replaced by halogen atoms. Many trihalomethanes find uses in industry as solvents or refrigerants. THMs are also environmental pollutants, and many are considered carcinogenic...
s (such as chloroform
Chloroform
Chloroform is an organic compound with formula CHCl3. It is one of the four chloromethanes. The colorless, sweet-smelling, dense liquid is a trihalomethane, and is considered somewhat hazardous...
) are not produced from organic contaminants. . Chlorine dioxide generated from sodium chlorite is approved by FDA under some conditions for disinfecting water used to wash fruits, vegetables, and poultry.
Sodium chlorite, NaClO2, sometimes in combination with zinc chloride
Zinc chloride
Zinc chloride is the name of chemical compound with the formula ZnCl2 and its hydrates. Zinc chlorides, of which nine crystalline forms are known, are colorless or white, and are highly soluble in water. ZnCl2 itself is hygroscopic and even deliquescent. Samples should therefore be protected from...
, also finds application as a component in therapeutic rinses, mouthwashes, toothpastes and gels, mouth sprays, as a teat dip for control of mastitis in dairy cattle
Mastitis in dairy cattle
Mastitis in dairy cattle is the persistent, inflammatory reaction of the udder tissue. This potentially fatal mammary gland infection is the most common disease in dairy cattle in the United States. It is also the most costly to the dairy industry...
, as preservative in eye drops, and in contact lens cleaning solution under the trade name Purite.
Under the brand name Oxine it is used for sanitizing air ducts and HVAC/R systems and animal containment areas (walls, floors, and other surfaces).
Chemical reagent
In organic synthesisOrganic synthesis
Organic synthesis is a special branch of chemical synthesis and is concerned with the construction of organic compounds via organic reactions. Organic molecules can often contain a higher level of complexity compared to purely inorganic compounds, so the synthesis of organic compounds has...
, sodium chlorite is frequently used as a reagent in the Pinnick oxidation
Pinnick oxidation
The Pinnick oxidation is also known as Lindgren oxidation. It is an organic reaction by which aldehydes can be oxidized into its corresponding carboxylic acid, originally developed by Lindgren and Nilsson. The typical reaction condition used today was modified by G. A. Kraus even before Pinnick. ...
for the oxidation of aldehyde
Aldehyde
An aldehyde is an organic compound containing a formyl group. This functional group, with the structure R-CHO, consists of a carbonyl center bonded to hydrogen and an R group....
s to carboxylic acid
Carboxylic acid
Carboxylic acids are organic acids characterized by the presence of at least one carboxyl group. The general formula of a carboxylic acid is R-COOH, where R is some monovalent functional group...
s. The reaction is usually performed in monosodium phosphate
Monosodium phosphate
Monosodium phosphate , also known as anhydrous monobasic sodium phosphate is a chemical compound of sodium with a phosphate counterion. It is used as a laxative and, in combination with other sodium phosphates, as a pH buffer....
buffered solution in the presence of a chlorine scavenger (usually 2-methyl-2-butene
Pentene
Pentene refers to all the alkenes with chemical formula . Each contains one double bond within its molecular structure. There are a total of five different compounds in this class, differing from each other by whether the carbon atoms are attached linearly or in a branched structure, and whether...
).
Recently, sodium chlorite has been used as an oxidizing agent to convert alkyl furans to the corresponding 4-oxo-2-alkenoic acids in a simple one pot synthesis.
Safety
Sodium chlorite, like many oxidizing agentOxidizing agent
An oxidizing agent can be defined as a substance that removes electrons from another reactant in a redox chemical reaction...
s, should be protected from inadvertent contamination by organic materials to avoid the formation of an explosive mixture. The chemical explodes on percussive impact, and will ignite if combined with a strong antioxidant
Antioxidant
An antioxidant is a molecule capable of inhibiting the oxidation of other molecules. Oxidation is a chemical reaction that transfers electrons or hydrogen from a substance to an oxidizing agent. Oxidation reactions can produce free radicals. In turn, these radicals can start chain reactions. When...
(reducing agent).
Toxicity
Sodium chlorite is a strong oxidant and can therefore be expected to cause clinical symptoms similar to the well known sodium chlorateSodium chlorate
Sodium chlorate is a chemical compound with the chemical formula . When pure, it is a white crystalline powder that is readily soluble in water. It is hygroscopic. It decomposes above 250 °C to release oxygen and leave sodium chloride...
: methemoglobinemia
Methemoglobinemia
Methemoglobinemia is a disorder characterized by the presence of a higher than normal level of methemoglobin in the blood. Methemoglobin is an oxidized form of hemoglobin that has an increased affinity for oxygen, resulting in a reduced ability to release oxygen to tissues. The oxygen–hemoglobin...
, hemolysis
Hemolysis
Hemolysis —from the Greek meaning "blood" and meaning a "loosing", "setting free" or "releasing"—is the rupturing of erythrocytes and the release of their contents into surrounding fluid...
, renal failure
Renal failure
Renal failure or kidney failure describes a medical condition in which the kidneys fail to adequately filter toxins and waste products from the blood...
. A dose of 10-15 grams of sodium chlorate
Sodium chlorate
Sodium chlorate is a chemical compound with the chemical formula . When pure, it is a white crystalline powder that is readily soluble in water. It is hygroscopic. It decomposes above 250 °C to release oxygen and leave sodium chloride...
can be lethal. Methemoglobemia had been demonstrated in rats and cats and recent studies by the EMEA
EMEA
EMEA may stand for:* the previous acronym of the European Medicines Agency, an EU regulatory agency for the evaluation of medicinal products* Europe, the Middle East and Africa...
have confirmed that the clinical symptomatology is very similar to the one caused by sodium chlorate
Sodium chlorate
Sodium chlorate is a chemical compound with the chemical formula . When pure, it is a white crystalline powder that is readily soluble in water. It is hygroscopic. It decomposes above 250 °C to release oxygen and leave sodium chloride...
in the rat, mouse, rabbit, and the green monkey.
Chlorocebus
Chlorocebus is a genus of medium-sized primates from the family of Old World monkeys. There are six species currently recognized, although some classify them all as a single species with numerous subspecies...
There is only one human case in the medical literature of chlorite
Chlorite
The chlorite ion is ClO2−. A chlorite is a compound that contains this group,with chlorine in oxidation state +3. Chlorites are also known as salts of chlorous acid.-Oxidation states:...
poisoning. It seems to confirm that the toxicity
Toxicity
Toxicity is the degree to which a substance can damage a living or non-living organisms. Toxicity can refer to the effect on a whole organism, such as an animal, bacterium, or plant, as well as the effect on a substructure of the organism, such as a cell or an organ , such as the liver...
is equal to sodium chlorate
Sodium chlorate
Sodium chlorate is a chemical compound with the chemical formula . When pure, it is a white crystalline powder that is readily soluble in water. It is hygroscopic. It decomposes above 250 °C to release oxygen and leave sodium chloride...
. From the analogy with sodium chlorate
Sodium chlorate
Sodium chlorate is a chemical compound with the chemical formula . When pure, it is a white crystalline powder that is readily soluble in water. It is hygroscopic. It decomposes above 250 °C to release oxygen and leave sodium chloride...
, even small amounts of about 1 gram can be expected to cause nausea
Nausea
Nausea , is a sensation of unease and discomfort in the upper stomach with an involuntary urge to vomit. It often, but not always, precedes vomiting...
, vomiting
Vomiting
Vomiting is the forceful expulsion of the contents of one's stomach through the mouth and sometimes the nose...
and even life-threatening hemolysis
Hemolysis
Hemolysis —from the Greek meaning "blood" and meaning a "loosing", "setting free" or "releasing"—is the rupturing of erythrocytes and the release of their contents into surrounding fluid...
in Glucose-6-Phosphate Dehydrogenase
Glucose-6-phosphate dehydrogenase
Glucose-6-phosphate dehydrogenase is a cytosolic enzyme in the pentose phosphate pathway , a metabolic pathway that supplies reducing energy to cells by maintaining the level of the co-enzyme nicotinamide adenine dinucleotide phosphate...
deficient persons.
Manufacture
The free acid, chlorous acidChlorous acid
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 and chloric acid :Although the acid is difficult to obtain in pure substance, the conjugate base,...
, 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
Sodium chlorate
Sodium chlorate is a chemical compound with the chemical formula . When pure, it is a white crystalline powder that is readily soluble in water. It is hygroscopic. It decomposes above 250 °C to release oxygen and leave sodium chloride...
, NaClO3. First, the explosive (only at concentrations greater than 10% in atmosphere) chlorine dioxide
Chlorine dioxide
Chlorine dioxide is a chemical compound with the formula ClO2. This yellowish-green gas crystallizes as bright orange crystals at −59 °C. As one of several oxides of chlorine, it is a potent and useful oxidizing agent used in water treatment and in bleaching....
, ClO2 is produced by reducing sodium chlorate in a strong acid solution with a suitable reducing agent (for example, sodium sulfite
Sodium sulfite
Sodium sulfite is a soluble sodium salt of sulfurous acid. It is a product of sulfur dioxide scrubbing, a part of the flue gas desulfurization process...
, sulfur dioxide
Sulfur dioxide
Sulfur dioxide is the chemical compound with the formula . It is released by volcanoes and in various industrial processes. Since coal and petroleum often contain sulfur compounds, their combustion generates sulfur dioxide unless the sulfur compounds are removed before burning the fuel...
, or hydrochloric acid
Hydrochloric acid
Hydrochloric acid is a solution of hydrogen chloride in water, that is a highly corrosive, strong mineral acid with many industrial uses. It is found naturally in gastric acid....
). The chlorine dioxide
Chlorine dioxide
Chlorine dioxide is a chemical compound with the formula ClO2. This yellowish-green gas crystallizes as bright orange crystals at −59 °C. As one of several oxides of chlorine, it is a potent and useful oxidizing agent used in water treatment and in bleaching....
is then absorbed into an alkaline solution and reduced with hydrogen peroxide
Hydrogen peroxide
Hydrogen peroxide is the simplest peroxide and an oxidizer. Hydrogen peroxide is a clear liquid, slightly more viscous than water. In dilute solution, it appears colorless. With its oxidizing properties, hydrogen peroxide is often used as a bleach or cleaning agent...
, yielding sodium chlorite.
Availability
In the United States sodium chlorite is available in industrial quantities from DuPontDuPont
E. I. du Pont de Nemours and Company , commonly referred to as DuPont, is an American chemical company that was founded in July 1802 as a gunpowder mill by Eleuthère Irénée du Pont. DuPont was the world's third largest chemical company based on market capitalization and ninth based on revenue in 2009...
.
General references
- "Chemistry of the Elements", N.N. Greenwood and A. Earnshaw, Pergamon Press, 1984.
- "Kirk-Othmer Concise Encyclopedia of Chemistry", Martin Grayson, Editor, John Wiley & Sons, Inc., 1985