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Wikipedia

Sodium hypochlorite

Sodium hypochlorite (commonly known in a dilute solution as bleach) is a chemical compound with the formula NaOCl or NaClO, comprising a sodium cation (Na+
) and a hypochlorite anion (OCl
orClO
). 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 pentahydrateNaOCl·5H
2
O
, a pale greenish-yellow solid which is not explosive and is stable if kept refrigerated.

Names
IUPAC name
Sodium hypochlorite
Other names
  • Antiformin
  • Bleach
  • Chloride of soda
In dilution:
  • Carrel-Dakin solution
  • Modified Dakin's solution
  • Surgical chlorinated soda solution
Identifiers
  • 7681-52-9 (anhydrous) Y
  • 10022-70-5 (pentahydrate) Y
3D model (JSmol)
ChEBI
ChemSpider
DrugBank
ECHA InfoCard 100.028.790
EC Number
  • 231-668-3
KEGG
RTECS number
  • NH3486300
UNII
UN number 1791
  • InChI=1S/ClO.Na/c1-2;/q-1;+1 Y
    Key: SUKJFIGYRHOWBL-UHFFFAOYSA-N Y
  • InChI=1/ClO.Na/c1-2;/q-1;+1
    Key: SUKJFIGYRHOWBL-UHFFFAOYAD
  • [Na+].[O-]Cl
Properties
NaOCl
Molar mass 74.442 g/mol
Appearance greenish-yellow solid (pentahydrate)
Odor chlorine-like and sweetish
Density 1.11 g/cm3
Melting point 18 °C (64 °F; 291 K) pentahydrate
Boiling point 101 °C (214 °F; 374 K) (decomposes)
29.3 g/100mL (0 °C)
Acidity (pKa) 7.5185
Basicity (pKb) 6.4815
Thermochemistry
-347.1 kJ/mol
Pharmacology
D08AX07 (WHO)
Hazards
Safety data sheet ICSC 1119 (solution, >10% active chlorine)
ICSC 0482 (solution, <10% active chlorine)
GHS pictograms
GHS Signal word Danger
H314, H410
P260, P264, P273, P280, P301+P330+P331, P303+P361+P353, P304+P340, P305+P351+P338, P310, P321, P363, P391, P405, P501
NFPA 704 (fire diamond)
Related compounds
Other anions
Sodium chloride
Sodium chlorite
Sodium chlorate
Sodium perchlorate
Other cations
Lithium hypochlorite
Calcium hypochlorite
Potassium hypochlorite
Related compounds
Hypochlorous acid
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Nverify (what is YN ?)
Infobox references

Sodium hypochlorite is most often encountered as a pale greenish-yellow dilute solution referred to as liquid bleach, which is a household chemical widely used (since the 18th century) as a disinfectant or a bleaching agent. In solution, the compound is unstable and easily decomposes, liberating chlorine, which is the active principle of such products. Sodium hypochlorite is the oldest and still most important chlorine-based bleach.

Its corrosive properties, common availability, and reaction products make it a significant safety risk. In particular, mixing liquid bleach with other cleaning products, such as acids found in limescale-removing products, will produce chlorine gas, which was used as a poison gas in World War I. A common urban legend states that mixing bleach with ammonia also releases chlorine, but in reality the two chemicals react differently, producing chloramines and/or nitrogen trichloride. With excess ammonia and sodium hydroxide, hydrazine may be generated.

Contents

Stability of the solid

Anhydrous sodium hypochlorite can be prepared but, like many hypochlorites, it is highly unstable and decomposes explosively on heating or friction. The decomposition is accelerated by carbon dioxide at atmospheric levels. It is a white solid with the orthorhombic crystal structure.

Sodium hypochlorite can also be obtained as a crystalline pentahydrateNaOCl·5H
2
O
, which is not explosive and is much more stable than the anhydrous compound. The formula is sometimes given as 2NaOCl·10H
2
O
.[citation needed] The transparent, light greenish-yellow, orthorhombic crystals contain 44% NaOCl by weight and melt at 25–27 °C. The compound decomposes rapidly at room temperature, so it must be kept under refrigeration. At lower temperatures, however, it is quite stable: reportedly only 1% decomposition after 360 days at 7 °C.

A 1966 US patent claims that stable solid sodium hypochlorite dihydrateNaOCl·2H
2
O
can be obtained by carefully excluding chloride ions (Cl
), which are present in the output of common manufacturing processes and are said to catalyze the decomposition of hypochlorite into chlorate (ClO
3
) and chloride. In one test, the dihydrate was claimed to show only 6% decomposition after 13.5 months storage at −25 °C. The patent also claims that the dihydrate can be reduced to the anhydrous form by vacuum drying at about 50 °C, yielding a solid that showed no decomposition after 64 hours at −25 °C.

Equilibria and stability of solutions

At typical ambient temperatures, sodium hypochlorite is more stable in dilute solutions that contain solvatedNa+
andOCl
ions. The density of the solution is 1.093 g/mL at 5% concentration, and 1.21 g/mL at 14%, 20 °C. Stoichiometric solutions are fairly alkaline, with pH 11 or higher since hypochlorous acid is a weak acid:

OCl
+H
2
O
⇌ HOCl +OH

The following species and equilibria are present in solutions ofNaOCl:

HOCl (aq) ⇌H+
+OCl
HOCl (aq) +Cl
+H+
Cl
2
(aq) +H
2
O
Cl
2
(aq) +Cl
Cl
3
Cl
2
(aq) ⇌Cl
2
(g)

The second equilibrium equation above will be shifted to the right if the chlorineCl
2
is allowed to escape as gas. The ratios ofCl
2
, HOCl, andOCl
in solution are also pH dependent. At pH below 2, the majority of the chlorine in the solution is in the form of dissolved elementalCl
2
. At pH greater than 7.4, the majority is in the form of hypochloriteClO
. The equilibrium can be shifted by adding acids (such as hydrochloric acid) or bases (such as sodium hydroxide) to the solution:

ClO
(aq) + 2 HCl (aq) →Cl
2
(g) +H
2
O
(aq) +Cl
(aq)
Cl
2
(g) + 2OH
ClO
(aq) +Cl
(aq) +H
2
O
(aq)

At a pH of about 4, such as obtained by the addition of strong acids like hydrochloric acid, the amount of undissociated (nonionized) HOCl is highest. The reaction can be written as:

ClO
+H+
⇌ HClO

Sodium hypochlorite solutions combined with acid evolve chlorine gas, particularly strongly at pH < 2, by the reactions:

HOCl (aq) +Cl
+H+
Cl
2
(aq) +H
2
O
Cl
2
(aq) ⇌Cl
2
(g)

At pH > 8, the chlorine is practically all in the form of hypochlorite anions (OCl
). The solutions are fairly stable at pH 11–12. Even so, one report claims that a conventional 13.6% NaOCl reagent solution lost 17% of its strength after being stored for 360 days at 7 °C. For this reason, in some applications one may use more stable chlorine-releasing compounds, such as calcium hypochloriteCa(ClO)
2
or trichloroisocyanuric acid(CNClO)
3
.

Anhydrous sodium hypochlorite is soluble in methanol, and solutions are stable.[citation needed]

Decomposition to chlorate or oxygen

In solution, under certain conditions, the hypochlorite anion may also disproportionate (autoxidize) to chloride and chlorate:

3ClO
+H+
HClO
3
+ 2Cl

In particular, this reaction occurs in sodium hypochlorite solutions at high temperatures, forming sodium chlorate and sodium chloride:

3NaOCl (aq) → 2NaCl (aq) +NaClO
3
(aq)

This reaction is exploited in the industrial production of sodium chlorate.

An alternative decomposition of hypochlorite produces oxygen instead:

2OCl
→ 2Cl
+O
2

In hot sodium hypochlorite solutions, this reaction competes with chlorate formation, yielding sodium chloride and oxygen gas:

2NaOCl (aq) → 2NaCl (aq) +O
2
(g)

These two decomposition reactions ofNaClO solutions are maximized at pH around 6. The chlorate-producing reaction predominates at pH above 6, while the oxygen one becomes significant below that. For example, at 80 °C, with NaOCl and NaCl concentrations of 80 mM, and pH 6–6.5, the chlorate is produced with ∼95% efficiency. The oxygen pathway predominates at pH 10. This decomposition is affected by light and metal ion catalysts such as copper, nickel, cobalt, and iridium. Catalysts like sodium dichromateNa
2
Cr
2
O
7
and sodium molybdateNa
2
MoO
4
may be added industrially to reduce the oxygen pathway, but a report claims that only the latter is effective.

Titration

Titration of hypochlorite solutions is often done by adding a measured sample to an excess amount of acidified solution of potassium iodide (KI) and then titrating the liberated iodine (I
2
) with a standard solution of sodium thiosulfate or phenyl arsine oxide, using starch as indicator, until the blue color disappears.

According to one US patent, the stability of sodium hypochlorite content of solids or solutions can be determined by monitoring the infrared absorption due to the O–Cl bond. The characteristic wavelength is given as 140.25 μm for water solutions, 140.05 μm for the solid dihydrate NaOCl·2H
2
O
, and 139.08 μm for the anhydrous mixed saltNa
2
(OCl)(OH)
.

Oxidation of organic compounds

Oxidation of starch by sodium hypochlorite, that adds carbonyl and carboxyl groups, is relevant to the production of modified starch products.

In the presence of a phase-transfer catalyst, alcohols are oxidized to the corresponding carbonyl compound (aldehyde or ketone). Sodium hypochlorite can also oxidize organic sulfides to sulfoxides or sulfones, disulfides or thiols to sulfonyl chlorides or bromides, imines to oxaziridines. It can also de-aromatize phenols.

Oxidation of metals and complexes

Heterogeneous reactions of sodium hypochlorite and metals such as zinc proceed slowly to give the metal oxide or hydroxide:

NaOCl + Zn → ZnO + NaCl

Homogeneous reactions with metal coordination complexes proceed somewhat faster. This has been exploited in the Jacobsen epoxidation.

Other reactions

If not properly stored in airtight containers, sodium hypochlorite reacts with carbon dioxide to form sodium carbonate:

2 NaOCl +CO2 + H2ONa
2
CO
3
+ 2 HOCl

Sodium hypochlorite reacts with most nitrogen compounds to form volatile monochloramine, dichloramines, and nitrogen trichloride:

NH
3
+ NaOCl →NH
2
Cl
+ NaOH
NH
2
Cl
+ NaOCl →NHCl
2
+ NaOH
NHCl
2
+ NaOCl →NCl
3
+ NaOH

Neutralization

Sodium thiosulfate is an effective chlorine neutralizer. Rinsing with a 5 mg/L solution, followed by washing with soap and water, will remove chlorine odor from the hands.

Chlorination of soda

Potassium hypochlorite was first produced in 1789 by Claude Louis Berthollet in his laboratory on the Quai de Javel in Paris, France, by passing chlorine gas through a solution of potash lye. The resulting liquid, known as "Eau de Javel" ("Javel water"), was a weak solution of potassium hypochlorite. Antoine Labarraque replaced potash lye by the cheaper soda lye, thus obtaining sodium hypochlorite (Eau de Labarraque).

Cl2 (g) + 2 NaOH (aq) → NaCl (aq) + NaClO (aq) + H2O (aq)

Hence, chlorine is simultaneously reduced and oxidized; this process is known as disproportionation.

The process is also used to prepare the pentahydrateNaOCl·5H
2
O
for industrial and laboratory use. In a typical process, chlorine gas is added to a 45–48% NaOH solution. Some of the sodium chloride precipitates and is removed by filtration, and the pentahydrate is then obtained by cooling the filtrate to 12 °C .

From calcium hypochlorite

Another method involved the reaction of sodium carbonate ("washing soda") with chlorinated lime ("bleaching powder"), a mixture of calcium hypochloriteCa(OCl)
2
, calcium chlorideCaCl
2
, and calcium hydroxideCa(OH)
2
:

Na
2
CO
3
(aq) +Ca(OCl)
2
(aq) →CaCO
3
(s) + 2NaOCl (aq)
Na
2
CO
3
(aq) +CaCl
2
(aq) →CaCO
3
(s) + 2NaCl (aq)
Na
2
CO
3
(aq) +Ca(OH)
2
(s) →CaCO
3
(s) + 2NaOH (aq)

This method was commonly used to produce hypochlorite solutions for use as a hospital antiseptic that was sold after World War I under the names "Eusol", an abbreviation for Edinburgh University Solution Of (chlorinated) Lime – a reference to the university's pathology department, where it was developed.

Electrolysis of brine

Near the end of the nineteenth century, E. S. Smith patented the chloralkali process: a method of producing sodium hypochlorite involving the electrolysis of brine to produce sodium hydroxide and chlorine gas, which then mixed to form sodium hypochlorite. The key reactions are:

2 Cl → Cl2 + 2 e (at the anode)
2H
2
O
+ 2 eH
2
+ 2HO
(at the cathode)

Both electric power and brine solution were in cheap supply at the time, and various enterprising marketers took advantage of the situation to satisfy the market's demand for sodium hypochlorite. Bottled solutions of sodium hypochlorite were sold under numerous trade names.

Today, an improved version of this method, known as the Hooker process (named after Hooker Chemicals, acquired by Occidental Petroleum), is the only large-scale industrial method of sodium hypochlorite production. In the process, sodium hypochlorite (NaClO) and sodium chloride (NaCl) are formed when chlorine is passed into cold dilute sodium hydroxide solution. The chlorine is prepared industrially by electrolysis with minimal separation between the anode and the cathode. The solution must be kept below 40 °C (by cooling coils) to prevent the undesired formation of sodium chlorate.

Commercial solutions always contain significant amounts of sodium chloride (common salt) as the main by-product, as seen in the equation above.

From hypochlorous acid and soda

A 1966 patent describes the production of solid stable dihydrateNaOCl·2H
2
O
by reacting a chloride-free solution of hypochlorous acidHClO (such as prepared from chlorine monoxideClO and water), with a concentrated solution of sodium hydroxide. In a typical preparation, 255 mL of a solution with 118 g/LHClO is slowly added with stirring to a solution of 40 g of NaOH in water 0 °C. Some sodium chloride precipitates and is removed by fitration. The solution is vacuum evaporated at 40–50 °C and 1–2 mmHg until the dihydrate crystallizes out. The crystals are vacuum-dried to produce a free-flowing crystalline powder.

The same principle was used in another 2050 patent to produce concentrated slurries of the pentahydrate NaClO·5H
2
O
. Typically, a 35% solution (by weight) of HClO is combined with sodium hydroxide at about or below 25 °C. The resulting slurry contains about 35% NaClO, and are relatively stable due to the low concentration of chloride.

From ozone and salt

Sodium hypochlorite can be easily produced for research purposes by reacting ozone with salt.

NaCl + O3 → NaClO + O2

This reaction happens at room temperature and can be helpful for oxidizing alcohols.

Main article: Bleach
Bleach packaged for household use, with 2.6% sodium hypochlorite

Household bleach sold for use in laundering clothes is a 3–8% solution of sodium hypochlorite at the time of manufacture. Strength varies from one formulation to another and gradually decreases with long storage. Sodium hydroxide is usually added in small amounts to household bleach to slow down the decomposition of NaClO.

Domestic use patio blackspot remover products are ~10% solutions of sodium hypochlorite.

A 10–25% solution of sodium hypochlorite is, according to Univar's safety sheet, supplied with synonyms or trade names bleach, Hypo, Everchlor, Chloros, Hispec, Bridos, Bleacol, or Vo-redox 9110.

A 12% solution is widely used in waterworks for the chlorination of water, and a 15% solution is more commonly used for disinfection of waste water in treatment plants. Sodium hypochlorite can also be used for point-of-use disinfection of drinking water, taking 0.2-2 mg of sodium hypochlorite per liter of water.

Dilute solutions (50 ppm to 1.5%) are found in disinfecting sprays and wipes used on hard surfaces.

Bleaching

Household bleach is, in general, a solution containing 3–8% sodium hypochlorite, by weight, and 0.01–0.05% sodium hydroxide; the sodium hydroxide is used to slow the decomposition of sodium hypochlorite into sodium chloride and sodium chlorate.

Cleaning

Sodium hypochlorite has destaining properties. Among other applications, it can be used to remove mold stains, dental stains caused by fluorosis, and stains on crockery, especially those caused by the tannins in tea. It has also been used in laundry detergents and as a surface cleaner. It is also used in Sodium hypochlorite washes.

Its bleaching, cleaning, deodorizing and caustic effects are due to oxidation and hydrolysis (saponification). Organic dirt exposed to hypochlorite becomes water-soluble and non-volatile, which reduces its odor and facilitates its removal.

Disinfection

Sodium hypochlorite in solution exhibits broad spectrum anti-microbial activity and is widely used in healthcare facilities in a variety of settings. It is usually diluted in water depending on its intended use. "Strong chlorine solution" is a 0.5% solution of hypochlorite (containing approximately 5000 ppm free chlorine) used for disinfecting areas contaminated with body fluids, including large blood spills (the area is first cleaned with detergent before being disinfected). It may be made by diluting household bleach as appropriate (normally 1 part bleach to 9 parts water). Such solutions have been demonstrated to inactivate both C. difficile and HPV. "Weak chlorine solution" is a 0.05% solution of hypochlorite used for washing hands, but is normally prepared with calcium hypochlorite granules.

"Dakin's Solution" is a disinfectant solution containing low concentration of sodium hypochlorite and some boric acid or sodium bicarbonate to stabilize the pH. It has been found to be effective with NaOCl concentrations as low as 0.025%.

US government regulations allow food processing equipment and food contact surfaces to be sanitized with solutions containing bleach, provided that the solution is allowed to drain adequately before contact with food, and that the solutions do not exceed 200 parts per million (ppm) available chlorine (for example, one tablespoon of typical household bleach containing 5.25% sodium hypochlorite, per gallon of water). If higher concentrations are used, the surface must be rinsed with potable water after sanitizing.

A similar concentration of bleach in warm water is used to sanitize surfaces prior to brewing of beer or wine. Surfaces must be rinsed with sterilized (boiled) water to avoid imparting flavors to the brew; the chlorinated byproducts of sanitizing surfaces are also harmful. The mode of disinfectant action of sodium hypochlorite is similar to that of hypochlorous acid.

Solutions containing more than 500 ppm available chlorine are corrosive to some metals, alloys and many thermoplastics (such as acetal resin) and need to be thoroughly removed afterwards, so the bleach disinfection is sometimes followed by an ethanol disinfection. Liquids containing sodium hypochlorite as the main active component are also used for household cleaning and disinfection, for example toilet cleaners. Some cleaners are formulated to be viscous so as not to drain quickly from vertical surfaces, such as the inside of a toilet bowl.

The undissociated (nonionized) hypochlorous acid is believed to react with and inactivate bacterial and viral enzymes.

Neutrophils of the human immune system produce small amounts of hypochlorite inside phagosomes, which digest bacteria and viruses.

Deodorizing

Sodium hypochlorite has deodorizing properties, which go hand in hand with its cleaning properties.

Waste water treatment

Sodium hypochlorite solutions have been used to treat dilute cyanide waste water, such as electroplating wastes. In batch treatment operations, sodium hypochlorite has been used to treat more concentrated cyanide wastes, such as silver cyanide plating solutions. Toxic cyanide is oxidized to cyanate (OCN) that is not toxic, idealized as follows:

CN + OCl → OCN + Cl

Sodium hypochlorite is commonly used as a biocide in industrial applications to control slime and bacteria formation in water systems used at power plants, pulp and paper mills, etc., in solutions typically of 10–15% by weight.

Endodontics

Sodium hypochlorite is the medicament of choice due to its efficacy against pathogenic organisms and pulp digestion in endodontic therapy. Its concentration for use varies from 0.5% to 5.25%. At low concentrations it dissolves mainly necrotic tissue; at higher concentrations it also dissolves vital tissue and additional bacterial species. One study has shown that Enterococcus faecalis was still present in the dentin after 40 minutes of exposure of 1.3% and 2.5% sodium hypochlorite, whereas 40 minutes at a concentration of 5.25% was effective in E. faecalis removal. In addition to higher concentrations of sodium hypochlorite, longer time exposure and warming the solution (60 °C) also increases its effectiveness in removing soft tissue and bacteria within the root canal chamber. 2% is a common concentration as there is less risk of an iatrogenic hypochlorite incident. A hypochlorite incident is an immediate reaction of severe pain, followed by edema, haematoma, and ecchymosis as a consequence of the solution escaping the confines of the tooth and entering the periapical space. This may be caused by binding or excessive pressure on the irrigant syringe, or it may occur if the tooth has an unusually large apical foramen.

Nerve agent neutralization

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At the various nerve agent (chemical warfare nerve gas) destruction facilities throughout the United States, 50% sodium hypochlorite is used to remove all traces of nerve agent or blister agent from Personal Protection Equipment after an entry is made by personnel into toxic areas. 50% sodium hypochlorite is also used to neutralize any accidental releases of nerve agent in the toxic areas. Lesser concentrations of sodium hypochlorite are used in similar fashion in the Pollution Abatement System to ensure that no nerve agent is released in furnace flue gas.

Reduction of skin damage

Dilute bleach baths have been used for decades to treat moderate to severe eczema in humans, but it has not been clear why they work. According to work published by researchers at the Stanford University School of Medicine in November 2013, a very dilute (0.005%) solution of sodium hypochlorite in water was successful in treating skin damage with an inflammatory component caused by radiation therapy, excess sun exposure or aging in laboratory mice. Mice with radiation dermatitis given daily 30-minute baths in bleach solution experienced less severe skin damage and better healing and hair regrowth than animals bathed in water. A molecule called nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) is known to play a critical role in inflammation, aging, and response to radiation. The researchers found that if NF-κB activity was blocked in elderly mice by bathing them in bleach solution, the animals' skin began to look younger, going from old and fragile to thicker, with increased cell proliferation. The effect diminished after the baths were stopped, indicating that regular exposure was necessary to maintain skin thickness.

It is estimated that there are about 3,300 accidents needing hospital treatment caused by sodium hypochlorite solutions each year in British homes (RoSPA, 2002).

Oxidation and corrosion

Sodium hypochlorite is a strong oxidizer. Oxidation reactions are corrosive. Solutions burn the skin and cause eye damage, especially when used in concentrated forms. As recognized by the NFPA, however, only solutions containing more than 40% sodium hypochlorite by weight are considered hazardous oxidizers. Solutions less than 40% are classified as a moderate oxidizing hazard (NFPA 430, 2000).

Household bleach and pool chlorinator solutions are typically stabilized by a significant concentration of lye (caustic soda, NaOH) as part of the manufacturing reaction. This additive will by itself cause caustic irritation or burns due to defatting and saponification of skin oils and destruction of tissue. The slippery feel of bleach on skin is due to this process.

Storage hazards

Contact of sodium hypochlorite solutions with metals may evolve flammable hydrogen gas. Containers may explode when heated due to release of chlorine gas.

Hypochlorite solutions are corrosive to common container materials such as stainless steel and aluminium. The few compatible metals include titanium (which however is not compatible with dry chlorine) and tantalum. Glass containers are safe. Some plastics and rubbers are affected too; safe choices include polyethylene (PE), high density polyethylene (HDPE, PE-HD), polypropylene (PP), some chlorinated and fluorinated polymers such as polyvinyl chloride (PVC), polytetrafluoroethylene (PTFE), and polyvinylidene fluoride (PVDF); as well as ethylene propylene rubber, and Viton.

Containers must allow venting of oxygen produced by decomposition over time, otherwise they may burst.

Reactions with other common products

Mixing bleach with some household cleaners can be hazardous.

Sodium hypochlorite solutions, such as liquid bleach, may release toxic chlorine gas when heated above 35 °C or mixed with an acid, such as hydrochloric acid or vinegar.

A 2008 study indicated that sodium hypochlorite and organic chemicals (e.g., surfactants, fragrances) contained in several household cleaning products can react to generate chlorinated volatile organic compounds (VOCs). These chlorinated compounds are emitted during cleaning applications, some of which are toxic and probable human carcinogens. The study showed that indoor air concentrations significantly increase (8–52 times for chloroform and 1–1170 times for carbon tetrachloride, respectively, above baseline quantities in the household) during the use of bleach containing products. The increase in chlorinated volatile organic compound concentrations was the lowest for plain bleach and the highest for the products in the form of "thick liquid and gel." The significant increases observed in indoor air concentrations of several chlorinated VOCs (especially carbon tetrachloride and chloroform) indicate that the bleach use may be a source that could be important in terms of inhalation exposure to these compounds. The authors suggested that using these cleaning products may significantly increase the cancer risk.

In particular, mixing hypochlorite bleaches with amines (for example, cleaning products that contain or release ammonia, ammonium salts, urea, or related compounds and biological materials such as urine) produces chloramines. These gaseous products can cause acute lung injury. Chronic exposure, for example, from the air at swimming pools where chlorine is used as the disinfectant, can lead to the development of atopic asthma.

Bleach can react violently with hydrogen peroxide and produce oxygen gas:

H2O2 (aq) + NaOCl (aq) → NaCl (aq) + H2O (aq) + O2 (g)

Explosive reactions or byproducts can also occur in industrial and laboratory settings when sodium hypochlorite is mixed with diverse organic compounds.

Limitations in health care

The UK's National Institute for Health and Care Excellence in October 2008 recommended that Dakin's solution should not be used in routine wound care.

In spite of its strong biocidal action, sodium hypochlorite per se has limited environmental impact, since the hypochlorite ion rapidly degrades before it can be absorbed by living beings.

However, one major concern arising from sodium hypochlorite use is that it tends to form persistent chlorinated organic compounds, including known carcinogens, that can be absorbed by organisms and enter the food chain. These compounds may be formed during household storage and use as well during industrial use. For example, when household bleach and wastewater were mixed, 1–2% of the available chlorine was observed to form organic compounds. As of 1994, not all the byproducts had been identified, but identified compounds include chloroform and carbon tetrachloride. The exposure to these chemicals from use is estimated to be within occupational exposure limits.

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Sodium hypochlorite
Sodium hypochlorite Article Talk Language Watch Edit Sodium hypochlorite commonly known in a dilute solution as bleach is a chemical compound with the formula NaOCl or NaClO comprising a sodium cation Na and a hypochlorite anion OCl or ClO It may also be viewed as the sodium salt of hypochlorous acid The anhydrous compound is unstable and may decompose explosively 2 3 It can be crystallized as a pentahydrate NaOCl 5H2 O a pale greenish yellow solid which is not explosive and is stable if kept refrigerated 4 5 NamesIUPAC name Sodium hypochloriteOther names AntiforminBleachChloride of sodaIn dilution Carrel Dakin solutionModified Dakin s solutionSurgical chlorinated soda solutionIdentifiersCAS Number 7681 52 9 anhydrous Y10022 70 5 pentahydrate Y3D model JSmol Interactive imageChEBI CHEBI 32146 YChemSpider 22756 YDrugBank DBSALT001517ECHA InfoCard 100 028 790EC Number 231 668 3KEGG D01711 YPubChem CID 23665760RTECS number NH3486300UNII DY38VHM5OD YUN number 1791CompTox Dashboard EPA DTXSID8021276InChI InChI 1S ClO Na c1 2 q 1 1 YKey SUKJFIGYRHOWBL UHFFFAOYSA N YInChI 1 ClO Na c1 2 q 1 1Key SUKJFIGYRHOWBL UHFFFAOYADSMILES Na O ClPropertiesChemical formula NaOClMolar mass 74 442 g molAppearance greenish yellow solid pentahydrate Odor chlorine like and sweetishDensity 1 11 g cm3Melting point 18 C 64 F 291 K pentahydrateBoiling point 101 C 214 F 374 K decomposes Solubility in water 29 3 g 100mL 0 C 1 Acidity pKa 7 5185Basicity pKb 6 4815ThermochemistryStd enthalpy of formation DfH 298 347 1 kJ molPharmacologyATC code D08AX07 WHO HazardsSafety data sheet ICSC 1119 solution gt 10 active chlorine ICSC 0482 solution lt 10 active chlorine GHS pictogramsGHS Signal word DangerGHS hazard statements H314 H410GHS precautionary statements P260 P264 P273 P280 P301 P330 P331 P303 P361 P353 P304 P340 P305 P351 P338 P310 P321 P363 P391 P405 P501NFPA 704 fire diamond 201OXRelated compoundsOther anions Sodium chloride Sodium chlorite Sodium chlorate Sodium perchlorateOther cations Lithium hypochlorite Calcium hypochlorite Potassium hypochloriteRelated compounds Hypochlorous acidExcept where otherwise noted data are given for materials in their standard state at 25 C 77 F 100 kPa N verify what is Y N Infobox references Sodium hypochlorite is most often encountered as a pale greenish yellow dilute solution referred to as liquid bleach which is a household chemical widely used since the 18th century as a disinfectant or a bleaching agent In solution the compound is unstable and easily decomposes liberating chlorine which is the active principle of such products Sodium hypochlorite is the oldest and still most important chlorine based bleach 6 7 Its corrosive properties common availability and reaction products make it a significant safety risk In particular mixing liquid bleach with other cleaning products such as acids found in limescale removing products will produce chlorine gas which was used as a poison gas in World War I 8 9 10 A common urban legend states that mixing bleach with ammonia also releases chlorine but in reality the two chemicals react differently producing chloramines and or nitrogen trichloride With excess ammonia and sodium hydroxide hydrazine may be generated Contents 1 Chemistry 1 1 Stability of the solid 1 2 Equilibria and stability of solutions 1 3 Decomposition to chlorate or oxygen 1 4 Titration 1 5 Oxidation of organic compounds 1 6 Oxidation of metals and complexes 1 7 Other reactions 1 8 Neutralization 2 Production 2 1 Chlorination of soda 2 2 From calcium hypochlorite 2 3 Electrolysis of brine 2 4 From hypochlorous acid and soda 2 5 From ozone and salt 3 Packaging and sale 4 Uses 4 1 Bleaching 4 2 Cleaning 4 3 Disinfection 4 4 Deodorizing 4 5 Waste water treatment 4 6 Endodontics 4 7 Nerve agent neutralization 4 8 Reduction of skin damage 5 Safety 5 1 Oxidation and corrosion 5 2 Storage hazards 5 3 Reactions with other common products 5 4 Limitations in health care 6 Environmental impact 7 See also 8 References 9 Bibliography 10 External linksChemistry EditStability of the solid Edit Anhydrous sodium hypochlorite can be prepared but like many hypochlorites it is highly unstable and decomposes explosively on heating or friction 2 The decomposition is accelerated by carbon dioxide at atmospheric levels 3 11 It is a white solid with the orthorhombic crystal structure 12 Sodium hypochlorite can also be obtained as a crystalline pentahydrate NaOCl 5H2 O which is not explosive and is much more stable than the anhydrous compound 3 4 The formula is sometimes given as 2NaOCl 10H2 O citation needed The transparent light greenish yellow orthorhombic 13 14 crystals contain 44 NaOCl by weight and melt at 25 27 C The compound decomposes rapidly at room temperature so it must be kept under refrigeration At lower temperatures however it is quite stable reportedly only 1 decomposition after 360 days at 7 C 5 15 A 1966 US patent claims that stable solid sodium hypochlorite dihydrate NaOCl 2H2 O can be obtained by carefully excluding chloride ions Cl which are present in the output of common manufacturing processes and are said to catalyze the decomposition of hypochlorite into chlorate ClO 3 and chloride In one test the dihydrate was claimed to show only 6 decomposition after 13 5 months storage at 25 C The patent also claims that the dihydrate can be reduced to the anhydrous form by vacuum drying at about 50 C yielding a solid that showed no decomposition after 64 hours at 25 C 16 Equilibria and stability of solutions Edit At typical ambient temperatures sodium hypochlorite is more stable in dilute solutions that contain solvated Na and OCl ions The density of the solution is 1 093 g mL at 5 concentration 17 and 1 21 g mL at 14 20 C 18 Stoichiometric solutions are fairly alkaline with pH 11 or higher 5 since hypochlorous acid is a weak acid OCl H2 O HOCl OH The following species and equilibria are present in solutions of NaOCl 19 HOCl aq H OCl HOCl aq Cl H Cl2 aq H2 O Cl2 aq Cl Cl 3 Cl2 aq Cl2 g The second equilibrium equation above will be shifted to the right if the chlorine Cl2 is allowed to escape as gas The ratios of Cl2 HOCl and OCl in solution are also pH dependent At pH below 2 the majority of the chlorine in the solution is in the form of dissolved elemental Cl2 At pH greater than 7 4 the majority is in the form of hypochlorite ClO 6 The equilibrium can be shifted by adding acids such as hydrochloric acid or bases such as sodium hydroxide to the solution ClO aq 2 HCl aq Cl2 g H2 O aq Cl aq Cl2 g 2 OH ClO aq Cl aq H2 O aq At a pH of about 4 such as obtained by the addition of strong acids like hydrochloric acid the amount of undissociated nonionized HOCl is highest The reaction can be written as ClO H HClO Sodium hypochlorite solutions combined with acid evolve chlorine gas particularly strongly at pH lt 2 by the reactions HOCl aq Cl H Cl2 aq H2 O Cl2 aq Cl2 g At pH gt 8 the chlorine is practically all in the form of hypochlorite anions OCl The solutions are fairly stable at pH 11 12 Even so one report claims that a conventional 13 6 NaOCl reagent solution lost 17 of its strength after being stored for 360 days at 7 C 5 For this reason in some applications one may use more stable chlorine releasing compounds such as calcium hypochlorite Ca ClO 2 or trichloroisocyanuric acid CNClO 3 Anhydrous sodium hypochlorite is soluble in methanol and solutions are stable citation needed Decomposition to chlorate or oxygen Edit In solution under certain conditions the hypochlorite anion may also disproportionate autoxidize to chloride and chlorate 20 3 ClO H HClO3 2 Cl In particular this reaction occurs in sodium hypochlorite solutions at high temperatures forming sodium chlorate and sodium chloride 20 21 3 NaOCl aq 2 NaCl aq NaClO3 aq This reaction is exploited in the industrial production of sodium chlorate An alternative decomposition of hypochlorite produces oxygen instead 2 OCl 2 Cl O2 In hot sodium hypochlorite solutions this reaction competes with chlorate formation yielding sodium chloride and oxygen gas 20 2 NaOCl aq 2 NaCl aq O2 g These two decomposition reactions of NaClO solutions are maximized at pH around 6 The chlorate producing reaction predominates at pH above 6 while the oxygen one becomes significant below that For example at 80 C with NaOCl and NaCl concentrations of 80 mM and pH 6 6 5 the chlorate is produced with 95 efficiency The oxygen pathway predominates at pH 10 20 This decomposition is affected by light 21 and metal ion catalysts such as copper nickel cobalt 20 and iridium 22 Catalysts like sodium dichromate Na2 Cr2 O7 and sodium molybdate Na2 MoO4 may be added industrially to reduce the oxygen pathway but a report claims that only the latter is effective 20 Titration Edit Titration of hypochlorite solutions is often done by adding a measured sample to an excess amount of acidified solution of potassium iodide KI and then titrating the liberated iodine I2 with a standard solution of sodium thiosulfate or phenyl arsine oxide using starch as indicator until the blue color disappears 14 According to one US patent the stability of sodium hypochlorite content of solids or solutions can be determined by monitoring the infrared absorption due to the O Cl bond The characteristic wavelength is given as 140 25 mm for water solutions 140 05 mm for the solid dihydrate NaOCl 2H2 O and 139 08 mm for the anhydrous mixed salt Na2 OCl OH 16 Oxidation of organic compounds Edit Oxidation of starch by sodium hypochlorite that adds carbonyl and carboxyl groups is relevant to the production of modified starch products 23 In the presence of a phase transfer catalyst alcohols are oxidized to the corresponding carbonyl compound aldehyde or ketone 24 5 Sodium hypochlorite can also oxidize organic sulfides to sulfoxides or sulfones disulfides or thiols to sulfonyl chlorides or bromides imines to oxaziridines 5 It can also de aromatize phenols 5 Oxidation of metals and complexes Edit Heterogeneous reactions of sodium hypochlorite and metals such as zinc proceed slowly to give the metal oxide or hydroxide NaOCl Zn ZnO NaCl Homogeneous reactions with metal coordination complexes proceed somewhat faster This has been exploited in the Jacobsen epoxidation Other reactions Edit If not properly stored in airtight containers sodium hypochlorite reacts with carbon dioxide to form sodium carbonate 2 NaOCl CO2 H2O Na2 CO3 2 HOCl Sodium hypochlorite reacts with most nitrogen compounds to form volatile monochloramine dichloramines and nitrogen trichloride NH3 NaOCl NH2 Cl NaOH NH2 Cl NaOCl NHCl2 NaOH NHCl2 NaOCl NCl3 NaOHNeutralization Edit Sodium thiosulfate is an effective chlorine neutralizer Rinsing with a 5 mg L solution followed by washing with soap and water will remove chlorine odor from the hands 25 Production EditChlorination of soda Edit Potassium hypochlorite was first produced in 1789 by Claude Louis Berthollet in his laboratory on the Quai de Javel in Paris France by passing chlorine gas through a solution of potash lye The resulting liquid known as Eau de Javel Javel water was a weak solution of potassium hypochlorite Antoine Labarraque replaced potash lye by the cheaper soda lye thus obtaining sodium hypochlorite Eau de Labarraque 26 27 Cl2 g 2 NaOH aq NaCl aq NaClO aq H2O aq Hence chlorine is simultaneously reduced and oxidized this process is known as disproportionation The process is also used to prepare the pentahydrate NaOCl 5H2 O for industrial and laboratory use In a typical process chlorine gas is added to a 45 48 NaOH solution Some of the sodium chloride precipitates and is removed by filtration and the pentahydrate is then obtained by cooling the filtrate to 12 C 5 From calcium hypochlorite Edit Another method involved the reaction of sodium carbonate washing soda with chlorinated lime bleaching powder a mixture of calcium hypochlorite Ca OCl 2 calcium chloride CaCl2 and calcium hydroxide Ca OH 2 Na2 CO3 aq Ca OCl 2 aq CaCO3 s 2 NaOCl aq Na2 CO3 aq CaCl2 aq CaCO3 s 2 NaCl aq Na2 CO3 aq Ca OH 2 s CaCO3 s 2 NaOH aq This method was commonly used to produce hypochlorite solutions for use as a hospital antiseptic that was sold after World War I under the names Eusol an abbreviation for Edinburgh University Solution Of chlorinated Lime a reference to the university s pathology department where it was developed 28 Electrolysis of brine Edit Near the end of the nineteenth century E S Smith patented the chloralkali process a method of producing sodium hypochlorite involving the electrolysis of brine to produce sodium hydroxide and chlorine gas which then mixed to form sodium hypochlorite 29 27 30 The key reactions are 2 Cl Cl2 2 e at the anode 2 H2 O 2 e H2 2 HO at the cathode Both electric power and brine solution were in cheap supply at the time and various enterprising marketers took advantage of the situation to satisfy the market s demand for sodium hypochlorite Bottled solutions of sodium hypochlorite were sold under numerous trade names Today an improved version of this method known as the Hooker process named after Hooker Chemicals acquired by Occidental Petroleum is the only large scale industrial method of sodium hypochlorite production In the process sodium hypochlorite NaClO and sodium chloride NaCl are formed when chlorine is passed into cold dilute sodium hydroxide solution The chlorine is prepared industrially by electrolysis with minimal separation between the anode and the cathode The solution must be kept below 40 C by cooling coils to prevent the undesired formation of sodium chlorate Commercial solutions always contain significant amounts of sodium chloride common salt as the main by product as seen in the equation above From hypochlorous acid and soda Edit A 1966 patent describes the production of solid stable dihydrate NaOCl 2H2 O by reacting a chloride free solution of hypochlorous acid HClO such as prepared from chlorine monoxide ClO and water with a concentrated solution of sodium hydroxide In a typical preparation 255 mL of a solution with 118 g L HClO is slowly added with stirring to a solution of 40 g of NaOH in water 0 C Some sodium chloride precipitates and is removed by fitration The solution is vacuum evaporated at 40 50 C and 1 2 mmHg until the dihydrate crystallizes out The crystals are vacuum dried to produce a free flowing crystalline powder 16 The same principle was used in another 2050 patent to produce concentrated slurries of the pentahydrate NaClO 5H2 O Typically a 35 solution by weight of HClO is combined with sodium hydroxide at about or below 25 C The resulting slurry contains about 35 NaClO and are relatively stable due to the low concentration of chloride 31 From ozone and salt Edit Sodium hypochlorite can be easily produced for research purposes by reacting ozone with salt NaCl O3 NaClO O2 This reaction happens at room temperature and can be helpful for oxidizing alcohols Packaging and sale EditMain article Bleach Bleach packaged for household use with 2 6 sodium hypochlorite Household bleach sold for use in laundering clothes is a 3 8 solution of sodium hypochlorite at the time of manufacture Strength varies from one formulation to another and gradually decreases with long storage Sodium hydroxide is usually added in small amounts to household bleach to slow down the decomposition of NaClO 6 Domestic use patio blackspot remover products are 10 solutions of sodium hypochlorite A 10 25 solution of sodium hypochlorite is according to Univar s safety sheet supplied with synonyms or trade names bleach Hypo Everchlor Chloros Hispec Bridos Bleacol or Vo redox 9110 32 A 12 solution is widely used in waterworks for the chlorination of water and a 15 solution is more commonly 33 used for disinfection of waste water in treatment plants Sodium hypochlorite can also be used for point of use disinfection of drinking water 34 taking 0 2 2 mg of sodium hypochlorite per liter of water 35 Dilute solutions 50 ppm to 1 5 are found in disinfecting sprays and wipes used on hard surfaces 36 37 Uses EditBleaching Edit Household bleach is in general a solution containing 3 8 sodium hypochlorite by weight and 0 01 0 05 sodium hydroxide the sodium hydroxide is used to slow the decomposition of sodium hypochlorite into sodium chloride and sodium chlorate 38 Cleaning Edit Sodium hypochlorite has destaining properties 39 Among other applications it can be used to remove mold stains dental stains caused by fluorosis 40 and stains on crockery especially those caused by the tannins in tea It has also been used in laundry detergents and as a surface cleaner It is also used in Sodium hypochlorite washes Its bleaching cleaning deodorizing and caustic effects are due to oxidation and hydrolysis saponification Organic dirt exposed to hypochlorite becomes water soluble and non volatile which reduces its odor and facilitates its removal Disinfection Edit See also Hypochlorous acid Sodium hypochlorite in solution exhibits broad spectrum anti microbial activity and is widely used in healthcare facilities in a variety of settings 41 It is usually diluted in water depending on its intended use Strong chlorine solution is a 0 5 solution of hypochlorite containing approximately 5000 ppm free chlorine used for disinfecting areas contaminated with body fluids including large blood spills the area is first cleaned with detergent before being disinfected 41 42 It may be made by diluting household bleach as appropriate normally 1 part bleach to 9 parts water 43 Such solutions have been demonstrated to inactivate both C difficile 41 and HPV 44 Weak chlorine solution is a 0 05 solution of hypochlorite used for washing hands but is normally prepared with calcium hypochlorite granules 42 Dakin s Solution is a disinfectant solution containing low concentration of sodium hypochlorite and some boric acid or sodium bicarbonate to stabilize the pH It has been found to be effective with NaOCl concentrations as low as 0 025 45 US government regulations allow food processing equipment and food contact surfaces to be sanitized with solutions containing bleach provided that the solution is allowed to drain adequately before contact with food and that the solutions do not exceed 200 parts per million ppm available chlorine for example one tablespoon of typical household bleach containing 5 25 sodium hypochlorite per gallon of water 46 If higher concentrations are used the surface must be rinsed with potable water after sanitizing A similar concentration of bleach in warm water is used to sanitize surfaces prior to brewing of beer or wine Surfaces must be rinsed with sterilized boiled water to avoid imparting flavors to the brew the chlorinated byproducts of sanitizing surfaces are also harmful The mode of disinfectant action of sodium hypochlorite is similar to that of hypochlorous acid Solutions containing more than 500 ppm available chlorine are corrosive to some metals alloys and many thermoplastics such as acetal resin and need to be thoroughly removed afterwards so the bleach disinfection is sometimes followed by an ethanol disinfection Liquids containing sodium hypochlorite as the main active component are also used for household cleaning and disinfection for example toilet cleaners 47 Some cleaners are formulated to be viscous so as not to drain quickly from vertical surfaces such as the inside of a toilet bowl The undissociated nonionized hypochlorous acid is believed to react with and inactivate bacterial and viral enzymes Neutrophils of the human immune system produce small amounts of hypochlorite inside phagosomes which digest bacteria and viruses Deodorizing Edit Sodium hypochlorite has deodorizing properties which go hand in hand with its cleaning properties 39 Waste water treatment Edit Sodium hypochlorite solutions have been used to treat dilute cyanide waste water such as electroplating wastes In batch treatment operations sodium hypochlorite has been used to treat more concentrated cyanide wastes such as silver cyanide plating solutions Toxic cyanide is oxidized to cyanate OCN that is not toxic idealized as follows CN OCl OCN Cl Sodium hypochlorite is commonly used as a biocide in industrial applications to control slime and bacteria formation in water systems used at power plants pulp and paper mills etc in solutions typically of 10 15 by weight Endodontics Edit Sodium hypochlorite is the medicament of choice due to its efficacy against pathogenic organisms and pulp digestion in endodontic therapy Its concentration for use varies from 0 5 to 5 25 At low concentrations it dissolves mainly necrotic tissue at higher concentrations it also dissolves vital tissue and additional bacterial species One study has shown that Enterococcus faecalis was still present in the dentin after 40 minutes of exposure of 1 3 and 2 5 sodium hypochlorite whereas 40 minutes at a concentration of 5 25 was effective in E faecalis removal 48 In addition to higher concentrations of sodium hypochlorite longer time exposure and warming the solution 60 C also increases its effectiveness in removing soft tissue and bacteria within the root canal chamber 48 2 is a common concentration as there is less risk of an iatrogenic hypochlorite incident 49 A hypochlorite incident is an immediate reaction of severe pain followed by edema haematoma and ecchymosis as a consequence of the solution escaping the confines of the tooth and entering the periapical space This may be caused by binding or excessive pressure on the irrigant syringe or it may occur if the tooth has an unusually large apical foramen 50 Nerve agent neutralization Edit This section does not cite any sources Please help improve this section by adding citations to reliable sources Unsourced material may be challenged and removed March 2020 Learn how and when to remove this template message At the various nerve agent chemical warfare nerve gas destruction facilities throughout the United States 50 sodium hypochlorite is used to remove all traces of nerve agent or blister agent from Personal Protection Equipment after an entry is made by personnel into toxic areas 50 sodium hypochlorite is also used to neutralize any accidental releases of nerve agent in the toxic areas Lesser concentrations of sodium hypochlorite are used in similar fashion in the Pollution Abatement System to ensure that no nerve agent is released in furnace flue gas Reduction of skin damage Edit Dilute bleach baths have been used for decades to treat moderate to severe eczema in humans 51 52 but it has not been clear why they work According to work published by researchers at the Stanford University School of Medicine in November 2013 a very dilute 0 005 solution of sodium hypochlorite in water was successful in treating skin damage with an inflammatory component caused by radiation therapy excess sun exposure or aging in laboratory mice Mice with radiation dermatitis given daily 30 minute baths in bleach solution experienced less severe skin damage and better healing and hair regrowth than animals bathed in water A molecule called nuclear factor kappa light chain enhancer of activated B cells NF kB is known to play a critical role in inflammation aging and response to radiation The researchers found that if NF kB activity was blocked in elderly mice by bathing them in bleach solution the animals skin began to look younger going from old and fragile to thicker with increased cell proliferation The effect diminished after the baths were stopped indicating that regular exposure was necessary to maintain skin thickness 51 53 Safety EditIt is estimated that there are about 3 300 accidents needing hospital treatment caused by sodium hypochlorite solutions each year in British homes RoSPA 2002 Oxidation and corrosion Edit Sodium hypochlorite is a strong oxidizer Oxidation reactions are corrosive Solutions burn the skin and cause eye damage especially when used in concentrated forms As recognized by the NFPA however only solutions containing more than 40 sodium hypochlorite by weight are considered hazardous oxidizers Solutions less than 40 are classified as a moderate oxidizing hazard NFPA 430 2000 Household bleach and pool chlorinator solutions are typically stabilized by a significant concentration of lye caustic soda NaOH as part of the manufacturing reaction This additive will by itself cause caustic irritation or burns due to defatting and saponification of skin oils and destruction of tissue The slippery feel of bleach on skin is due to this process Storage hazards Edit Contact of sodium hypochlorite solutions with metals may evolve flammable hydrogen gas Containers may explode when heated due to release of chlorine gas 11 Hypochlorite solutions are corrosive to common container materials such as stainless steel 5 and aluminium The few compatible metals include titanium which however is not compatible with dry chlorine and tantalum 6 Glass containers are safe 5 Some plastics and rubbers are affected too safe choices include polyethylene PE high density polyethylene HDPE PE HD polypropylene PP 5 some chlorinated and fluorinated polymers such as polyvinyl chloride PVC polytetrafluoroethylene PTFE and polyvinylidene fluoride PVDF as well as ethylene propylene rubber and Viton 6 Containers must allow venting of oxygen produced by decomposition over time otherwise they may burst 2 Reactions with other common products Edit Mixing bleach with some household cleaners can be hazardous Sodium hypochlorite solutions such as liquid bleach may release toxic chlorine gas when heated above 35 C 11 or mixed with an acid such as hydrochloric acid or vinegar A 2008 study indicated that sodium hypochlorite and organic chemicals e g surfactants fragrances contained in several household cleaning products can react to generate chlorinated volatile organic compounds VOCs 54 These chlorinated compounds are emitted during cleaning applications some of which are toxic and probable human carcinogens The study showed that indoor air concentrations significantly increase 8 52 times for chloroform and 1 1170 times for carbon tetrachloride respectively above baseline quantities in the household during the use of bleach containing products The increase in chlorinated volatile organic compound concentrations was the lowest for plain bleach and the highest for the products in the form of thick liquid and gel The significant increases observed in indoor air concentrations of several chlorinated VOCs especially carbon tetrachloride and chloroform indicate that the bleach use may be a source that could be important in terms of inhalation exposure to these compounds The authors suggested that using these cleaning products may significantly increase the cancer risk 54 In particular mixing hypochlorite bleaches with amines for example cleaning products that contain or release ammonia ammonium salts urea or related compounds and biological materials such as urine produces chloramines 55 11 These gaseous products can cause acute lung injury Chronic exposure for example from the air at swimming pools where chlorine is used as the disinfectant can lead to the development of atopic asthma 56 Bleach can react violently with hydrogen peroxide and produce oxygen gas H2O2 aq NaOCl aq NaCl aq H2O aq O2 g Explosive reactions or byproducts can also occur in industrial and laboratory settings when sodium hypochlorite is mixed with diverse organic compounds 11 Limitations in health care Edit The UK s National Institute for Health and Care Excellence in October 2008 recommended that Dakin s solution should not be used in routine wound care 57 Environmental impact EditIn spite of its strong biocidal action sodium hypochlorite per se has limited environmental impact since the hypochlorite ion rapidly degrades before it can be absorbed by living beings 58 However one major concern arising from sodium hypochlorite use is that it tends to form persistent chlorinated organic compounds including known carcinogens that can be absorbed by organisms and enter the food chain These compounds may be formed during household storage and use as well during industrial use 38 For example when household bleach and wastewater were mixed 1 2 of the available chlorine was observed to form organic compounds 38 As of 1994 not all the byproducts had been identified but identified compounds include chloroform and carbon tetrachloride 38 The exposure to these chemicals from use is estimated to be within occupational exposure limits 38 See also EditCalcium hypochlorite Ca OCl 2 bleaching powder Potassium hypochlorite KOCl the original Javel water Lithium hypochlorite LiOCl Sodium hypochlorite washes Mixed oxidantReferences Edit Budavari S O Neil M Smith A Heckelman P Obenchain J 1996 Sodium hypochlorite The Merck Index 12th ed p 1478 ISBN 978 0 911910 12 4 a b c Urben P 2006 Bretherick s Handbook of Reactive Chemical Hazards 1 7th ed p 1433 ISBN 978 0 08 052340 8 a b c Hamano A 1997 The formation and decomposition of sodium hypochlorite anhydrous salt and its pentahydrate Science and Technology of Energetic Materials 58 4 152 155 a b Applebey MP 1919 Sodium hypochlorite Journal of the Chemical Society Transactions 115 XCVI 1106 1109 doi 10 1039 CT9191501106 a b c d e f g h i j k Kirihara M Okada T Sugiyama Y Akiyoshi M Matsunaga T Kimura Y December 2017 Sodium Hypochlorite Pentahydrate Crystals NaOCl 5H2O A Convenient and Environmentally Benign Oxidant for Organic Synthesis Organic Process Research amp Development 21 12 1925 37 doi 10 1021 acs oprd 7b00288 a b c d e OxyChem Sodium Hypochlorite Handbook PDF oxy com OxyChem Pamphlet 96 The Sodium Hypochorite Manual www chlorineinstitute org The Chlorine Institute Faith Thomas 2014 Behind the gas mask the U S chemical warfare service in war and peace Champaign IL University of Illinois Press p 9 ISBN 978 0252080265 Retrieved 14 April 2017 April 22 1915 Germans introduce poison gas This Day In History Retrieved 14 April 2017 Gross Daniel A Spring 2015 Chemical Warfare From the European Battlefield to the American Laboratory Distillations 1 1 16 23 Retrieved 20 March 2018 a b c d e 2013 Sodium Hypochlorite Stanford Linear Accelerator Laboratory Safe Handling Guideline chapter 53 product 202 Accessed on 2018 06 12 Yaws CL 2015 The Yaws Handbook of Physical Properties for Hydrocarbons and Chemicals 2nd ed Gulf Professional Publishing p 734 ISBN 978 0 12 801146 1 Sodium Hypochlorite Pentahydrate NaOCl 5H2 O MatWeb Material Property Data website Retrieved 12 July 2018 a b Sodium Hypochlorite StudFiles Retrieved 14 June 2018 Okada T Asawa T Sugiyama Y Iwai T Kirihara M Kimura Y June 2016 Sodium hypochlorite pentahydrate NaOCl 5H2O crystals An effective re oxidant for TEMPO oxidation Tetrahedron 72 22 2818 27 doi 10 1016 j tet 2016 03 064 a b c US 3498924 Walsh RH Dietz A Process for preparing stable sodium hypochlorites issued 1966 Sodium hypochlorite PubChem U S National Library of Medicine Environment Canada 1985 Tech Info for Problem Spills Sodium Hypochlorite Draft Wang L Bassiri M Najafi R Najafi K Yang J Khosrovi B et al April 2007 Hypochlorous acid as a potential wound care agent part I Stabilized hypochlorous acid a component of the inorganic armamentarium of innate immunity Journal of Burns and Wounds 6 e5 PMC 1853323 PMID 17492050 a b c d e f Sandin S Karlsson RK Cornell A April 2015 Catalyzed and uncatalyzed decomposition of hypochlorite in dilute solutions Industrial amp Engineering Chemistry Research 54 15 3767 74 doi 10 1021 ie504890a a b Hamano A Ikeda A 1995 The pH effect on the photodecomposition of sodium hypochlorite solution Science and Technology of Energetic Materials 56 2 59 63 Ayres GH Booth MH 1955 Catalytic Decomposition of Hypochlorite Solution by Iridium Compounds I The pH Time Relationship Journal of the American Chemical Society 77 4 825 827 doi 10 1021 ja01609a001 ASC PT Asahimas Chemical 2009 Sodium hypochlorite Online product description Accessed on 2018 06 14 Mirafzal GA Lozeva AM 1998 Phase transfer catalyzed oxidation of alcohols with sodium hypochlorite Tetrahedron Letters 39 40 7263 7266 doi 10 1016 S0040 4039 98 01584 6 Standard Methods for the Examination of Water and Wastewater PDF www umass edu American Public Health Association American Water Works Association Water Environment Federation Retrieved 26 January 2017 Vogt H Balej J Bennett JE Wintzer P Sheikh SA Gallone P 2007 Chlorine Oxides and Chlorine Oxygen Acids Ullmann s Encyclopedia of Industrial Chemistry 7th ed Wiley p 2 a b Sodium hypochlorite as a disinfectant Lenntech com Retrieved 7 August 2011 eusol Oxford English Dictionary Retrieved 3 July 2014 May P Bleach Sodium Hypochlorite University of Bristol Archived from the original on 13 December 2016 Retrieved 13 December 2016 How Products Are Made Volume 2 May 2011 US 5194238 Duncan BL Ness RC Process for the production of highly pure concentrated slurries of sodium hypochlorite issued 1991 SAFETY DATA SHEET Sodium Hypochlorite PDF Univar 9 August 2007 Wastewater Engineering Treatment Disposal amp Reuse 3rd ed Metcalf amp Eddy Inc 1991 p 497 Lantagne DS 2018 Sodium hypochlorite dosage for household and emergency water treatment IWA Publishing 16 1 What is Chlorination Vieira ER 1999 Elementary Food Science Springer pp 381 382 ISBN 978 0 8342 1657 0 Wilhelm N Kaufmann A Blanton E Lantagne D February 2018 Sodium hypochlorite dosage for household and emergency water treatment updated recommendations Journal of Water and Health 16 1 112 125 doi 10 2166 wh 2017 012 PMID 29424725 a b c d e Smith WT 1994 Human and Environmental Safety of Hypochlorite In Proceedings of the 3rd World Conference on Detergents Global Perspectives pp 183 5 a b Benefits and Safety Aspects of Hypochlorite Formulated in Domestic Products PDF AISE International Association for Soaps Detergents and Maintenance Products March 1997 Archived from the original PDF on 30 March 2014 This Support Dossier deals with information on the environmental and human safety evaluation of hypochlorite and on its benefits as a disinfecting deodorising and stain removing agent Cardenas Flores A Flores Reyes H Gordillo Moscoso A Castanedo Cazares JP Pozos Guillen A 2009 Clinical efficacy of 5 sodium hypochlorite for removal of stains caused by dental fluorosis The Journal of Clinical Pediatric Dentistry 33 3 187 91 doi 10 17796 jcpd 33 3 c6282t1054584157 PMID 19476089 a b c Rutala WA Weber DJ 15 February 2017 2008 Guideline for Disinfection and Sterilization in Healthcare Facilities PDF www cdc gov Retrieved 29 August 2017 a b For General Healthcare Settings in West Africa How to Prepare and Use Chlorine Solutions Ebola Hemorrhagic Fever Centers for Disease Control and Prevention Retrieved 27 April 2016 How to Make Strong 0 5 Chlorine Solution from Liquid Bleach PDF Centers for Disease Control and Prevention Meyers J Ryndock E Conway MJ Meyers C Robison R June 2014 Susceptibility of high risk human papillomavirus type 16 to clinical disinfectants The Journal of Antimicrobial Chemotherapy 69 6 1546 50 doi 10 1093 jac dku006 PMC 4019329 PMID 24500190 Heggers JP Sazy JA Stenberg BD Strock LL McCauley RL Herndon DN Robson MC 1991 Bactericidal and wound healing properties of sodium hypochlorite solutions the 1991 Lindberg Award The Journal of Burn Care amp Rehabilitation 12 5 420 4 doi 10 1097 00004630 199109000 00005 PMID 1752875 21 CFR Part 178 Toilet Cleaners Learn About Chemicals Around Your House Pesticides US EPA United States Environmental Protection Agency 9 May 2012 a b Root Canal Irrigants and Disinfectants Endodontics Colleagues for Excellence Published for the Dental Professional Community by the American Association of Endodontists Winter 2011 Torabinejad M Walton R 2008 Endodontics VitalBook 4th ed W B Saunders Company p 265 Hulsmann M Hahn W May 2000 Complications during root canal irrigation literature review and case reports PDF International Endodontic Journal 33 3 186 93 doi 10 1046 j 1365 2591 2000 00303 x PMID 11307434 a b Conger K 15 November 2013 Inflammatory skin damage in mice blocked by bleach solution study finds Stanford School of Medicine Archived from the original on 7 December 2013 Pett K Batta K Vlachou C Nicholls G Bleach baths using Milton Sterilising Fluid for recurrent infected atopic eczema Archived from the original on 12 December 2013 Cite journal requires journal help Leung TH Zhang LF Wang J Ning S Knox SJ Kim SK December 2013 Topical hypochlorite ameliorates NF kB mediated skin diseases in mice The Journal of Clinical Investigation 123 12 5361 70 doi 10 1172 JCI70895 PMC 3859383 PMID 24231355 a b Odabasi M March 2008 Halogenated volatile organic compounds from the use of chlorine bleach containing household products Environmental Science amp Technology 42 5 1445 51 Bibcode 2008EnST 42 1445O doi 10 1021 es702355u PMID 18441786 Lay summary Krieger GR Sullivan Jr JB 2001 Clinical environmental health and toxic exposures 2 ed Philadelphia Pa u a Lippincott Williams amp Wilkins p 968 ISBN 9780683080278 Retrieved 30 August 2016 Nickmilder M Carbonnelle S Bernard A February 2007 House cleaning with chlorine bleach and the risks of allergic and respiratory diseases in children Pediatric Allergy and Immunology 18 1 27 35 doi 10 1111 j 1399 3038 2006 00487 x PMID 17295796 S2CID 24606118 Do not use Eusol and gauze to manage surgical wounds that are healing by secondary intention October 2008 NICE London Archived 14 July 2014 at the Wayback Machine Accessed 3 July 2014 ASC PT Asahimas Chemical 2009 Sodium hypochlorite 10 Online Material Safety Data Sheet MSDS Accessed on 2018 06 14 Bibliography EditJones FL December 1972 Chloride poisoning from mixing household cleaners JAMA 222 10 1312 doi 10 1001 jama 222 10 1312 PMID 4678160 Bonnard M Brondeau MT Falcy M Jargot D Miraval S Protois J Schneider O Eaux et extraits de Javel Hypochlorite de sodium en solution Fiche Toxicologique 157 External links EditInternational Chemical Safety Card 0482 solutions lt 10 active Cl International Chemical Safety Card 1119 solutions gt 10 active Cl Institut national de recherche et de securite in French Home and Leisure Accident Statistics 2002 UK RoSPA Emergency Disinfection of Drinking Water United States Environmental Protection Agency Chlorinated Drinking Water IARC Monograph NTP Study Report TR 392 Chlorinated amp Chloraminated Water US NIH Guidelines for the Use of Chlorine Bleach as a Sanitizer in Food Processing Operations Oklahoma State University Retrieved from https en wikipedia org w index php title Sodium hypochlorite amp oldid 1058896040, wikipedia, wiki, book,

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