| Revision as of 08:29, 2 February 2011 editBeetstra (talk | contribs)Edit filter managers, Administrators172,031 edits Script assisted update of identifiers from ChemSpider, CommonChemistry and FDA for the Chem/Drugbox validation project - Updated: ChEMBL. |
Latest revision as of 05:40, 1 December 2024 edit Citation bot (talk | contribs)Bots5,391,407 edits Add: newspaper, bibcode, authors 1-1. Removed parameters. Some additions/deletions were parameter name changes. | Use this bot. Report bugs. | Suggested by Abductive | Category:Misplaced Pages articles needing clarification from November 2024 | #UCB_Category 1/875 |
| Line 1: |
Line 1: |
|
|
{{Chembox |
|
{{expert-subject|Chemicals|date=January 2010}} |
|
|
|
| Verifiedfields = changed |
|
|
|
|
|
| Watchedfields = changed |
|
{{chembox |
|
|
| verifiedrevid = 399712814 |
|
| verifiedrevid = 411542258 |
|
| Name = Chloramine |
|
| Name = |
|
| ImageFile = Chloramine-2D.png |
|
| ImageFile = Chloramine-2D.png |
|
|
| ImageFile_Ref = {{chemboximage|correct|??}} |
|
| ImageSize = 140px |
|
|
|
| ImageSize = 100 |
|
| ImageName = Chloramine |
|
|
|
| ImageName = Stereo, skeletal formula of chloramine with all explicit hydrogens added |
|
| ImageFile1 = Chloramine-3D-vdW.png |
|
|
|
| ImageFile1 = Chloramine-3D-vdW.png |
|
| ImageSize1 = 140px |
|
|
|
| ImageFile1_Ref = {{chemboximage|correct|??}} |
|
| ImageName1 = Chloramine |
|
|
|
| ImageSize1 = 100 |
|
| OtherNames = Monochloramine<br />Chloramide<br />Chloroazane |
|
|
|
| ImageName1 = Spacefill model of chloramine |
|
|
| OtherNames = {{Unbulleted list |Chloramine |Chloramide<ref>{{cite web| url=https://cameochemicals.noaa.gov/chemical/19968| title= CHLORAMINE |website=CAMEO Chemicals |publisher=NOAA}}</ref>}} |
|
|
| IUPACName = |
|
|
| SystematicName = |
|
| Section1 = {{Chembox Identifiers |
|
| Section1 = {{Chembox Identifiers |
|
| PubChem = 25423 |
|
| CASNo = 10599-90-3 |
|
|
| CASNo_Ref = {{cascite|correct|CAS}} |
|
| InChI = 1/ClH2N/c1-2/h2H2 |
|
|
|
| ChEMBL_Ref = {{ebicite|correct|EBI}} |
|
| SMILES = ClN |
|
|
| InChIKey = QDHHCQZDFGDHMP-UHFFFAOYAS |
|
|
| ChEMBL = 1162370 |
|
| ChEMBL = 1162370 |
|
|
| ChEBI = 82415 |
|
| StdInChI_Ref = {{stdinchicite|correct|chemspider}} |
|
|
|
| PubChem = 25423 |
|
|
| ChemSpiderID = 23735 |
|
|
| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}} |
|
|
| EINECS = 234-217-9 |
|
|
| KEGG = C19359 |
|
|
| KEGG_Ref = {{keggcite|correct|kegg}} |
|
|
| MeSHName = chloramine |
|
|
| UNNumber = 3093 |
|
|
| UNII = KW8K411A1P |
|
|
| SMILES = NCl |
|
| StdInChI = 1S/ClH2N/c1-2/h2H2 |
|
| StdInChI = 1S/ClH2N/c1-2/h2H2 |
|
| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}} |
|
| StdInChI_Ref = {{stdinchicite|changed|chemspider}} |
|
| StdInChIKey = QDHHCQZDFGDHMP-UHFFFAOYSA-N |
|
| StdInChIKey = QDHHCQZDFGDHMP-UHFFFAOYSA-N |
|
|
| StdInChIKey_Ref = {{stdinchicite|changed|chemspider}} |
|
| CASNo = 10599-90-3 |
|
|
|
}} |
|
| CASNo_Ref = {{cascite|correct|CAS}} |
|
|
| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}} |
|
|
| ChemSpiderID = 23735 |
|
|
}} |
|
|
| Section2 = {{Chembox Properties |
|
| Section2 = {{Chembox Properties |
|
| Formula = NH<sub>2</sub>Cl |
|
| Formula = {{Chem|NH|2|Cl}} |
|
| MolarMass = 51.48 g/mol |
|
| MolarMass = 51.476 g mol<sup>−1</sup> |
|
| Appearance = colorless |
|
| Appearance = Colorless gas |
|
|
| MeltingPtC = −66 |
|
| Solvent = other solvents |
|
|
|
| pKa = 14 |
|
| SolubleOther = Soluble |
|
|
|
| pKb = 15 |
|
| MeltingPt = −66 °C |
|
|
|
}} |
|
| BoilingPt = |
|
|
|
| Section4 = |
|
}} |
|
|
|
| Section5 = |
|
| Section8 = {{Chembox Related |
|
|
|
| Section6 = |
|
| OtherCpds = ]<br/>]}} |
|
|
|
| Section7 = {{Chembox Hazards |
|
|
| ExternalSDS = |
|
|
| GHSPictograms = {{GHS07}} {{GHS08}} {{GHS05}} |
|
|
| GHSSignalWord = Danger |
|
|
| HPhrases = {{H-phrases|290|314|315|319|335|372|412}} |
|
|
| PPhrases = {{P-phrases|234|260|261|264|270|271|273|280|301+330+331|302+352|303+361+353|304+340|305+351+338|310|312|314|321|332+313|337+313|362|363|390|403+233|404|405|501}} |
|
|
| NFPA-F = 1 |
|
|
| NFPA-H = 3 |
|
|
| NFPA-R = 1 |
|
|
| NFPA-S = ACID |
|
|
| NFPA_ref = <ref name="SDS-Fisher">{{cite web |url=https://www.fishersci.com/shop/msdsproxy?storeId=10652&productName=O1779250 |title=Chloramine T Trihydrate SDS |website=Fisher}}{{Dead link|date=October 2023 |bot=InternetArchiveBot |fix-attempted=yes}}</ref> |
|
|
| LD50 = 935 mg/kg (rat, oral)<ref name="SDS-Fisher"/> |
|
|
| MainHazards = Corrosive acid |
|
|
| IngestionHazard = Corrosive; nausea and vomiting |
|
|
| InhalationHazard = Corrosive |
|
|
| EyeHazard = Irritation |
|
|
| SkinHazard = Irritation |
|
|
}} |
|
|
|Section8={{Chembox Related |
|
|
| OtherCompounds = {{ubl|]|]|]|]}} |
|
|
}} |
|
}} |
|
}} |
|
|
|
|
|
'''Chloramine''' (monochloramine) is an ] with the ] NH<sub>2</sub>Cl. It is a colourless liquid at room temperature, but it is usually handled as a dilute solution where it is used as a ]. The term chloramine also refers to a family of ]s with the formulas R<sub>2</sub>NCl and RNCl<sub>2</sub> (R is an organic group). ], NHCl<sub>2</sub>, and ], NCl<sub>3</sub>, are also well known. |
|
'''Monochloramine''', often called '''chloramine''', is the ] with the formula NH<sub>2</sub>Cl. Together with ] (NHCl<sub>2</sub>) and ] (NCl<sub>3</sub>), it is one of the three ] of ].<ref>{{Greenwood&Earnshaw2nd}}</ref> It is a colorless liquid at its ] of {{cvt|−66|°C}}, but it is usually handled as a dilute ], in which form it is sometimes used as a ]. Chloramine is too unstable to have its ] measured.<ref>{{cite book|last1=Lawrence|first1=Stephen A.|title=Amines: Synthesis, Properties and Applications|date=2004|publisher=Cambridge University Press|isbn=9780521782845|page=172|url=https://books.google.com/books?id=35xwBwjhe2MC&pg=PA172|language=en}}</ref> |
|
|
|
|
|
==Water treatment== |
|
|
{{See also|Chloramination}} |
|
|
Chloramine is used as a ] for water. It is less aggressive than ] and more stable against light than ]s.<ref name="eoic" /> |
|
|
|
|
|
===Drinking water disinfection=== |
|
|
Chloramine is commonly used in low ]s as a secondary ] in ] as an alternative to ]. This application is increasing. ] (referred to in ] as free chlorine) is being displaced by chloramine—to be specific, monochloramine—which is much less reactive and does not dissipate as rapidly as free chlorine. Chloramine also has a much lower, but still active, tendency than free chlorine to convert organic materials into ]s such as ] and ]. Such compounds have been identified as ]s and in 1979 the ] (EPA) began regulating their levels in US ].<ref>{{Cite web|url=http://www.epa.gov/fedrgstr/EPA-WATER/2006/January/Day-04/w03.pdf|title = Govinfo}}</ref> |
|
|
|
|
|
Some of the unregulated byproducts may possibly pose greater health risks than the regulated chemicals.<ref>{{cite journal|author=Stuart W. Krasner |title=The formation and control of emerging disinfection by-products of health concern |journal=Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences |publisher=Philosophical Transactions of the Royal Society |volume=367 |issue=1904 |pages=4077–95 |date=2009-10-13 |doi=10.1098/rsta.2009.0108|pmid=19736234 |bibcode=2009RSPTA.367.4077K |doi-access=free}}</ref>{{Clarification needed|date=November 2024|reason=How? Why is it not known?}} |
|
|
|
|
|
Due to its acidic nature, adding chloramine to the water supply may increase exposure to ], especially in areas with older housing; this exposure can result in increased ], which may pose a significant health risk. Fortunately, water treatment plants can add caustic chemicals at the plant which have the dual purpose of reducing the corrosivity of the water, and stabilizing the disinfectant.<ref>{{cite journal |author=Marie Lynn Miranda |title=Changes in Blood Lead Levels Associated with Use of Chloramines in Water Treatment Systems |journal=Environmental Health Perspectives |date=February 2007 |volume=115 |issue=2 |pages=221–5 |doi=10.1289/ehp.9432 |pmid=17384768 |pmc=1817676|bibcode=2007EnvHP.115..221M |display-authors=etal}}</ref> |
|
|
|
|
|
===Swimming pool disinfection=== |
|
|
|
|
|
In ]s, chloramines are formed by the reaction of free chlorine with ]s present in ]s, mainly those biological in origin (e.g., ] in ] and ]). Chloramines, compared to free chlorine, are both less effective as a ] and, if not managed correctly, more irritating to the eyes of swimmers. Chloramines are responsible for the distinctive "chlorine" smell of swimming pools, which is often misattributed to elemental chlorine by the public.<ref>{{cite book |last=Donegan |first=Fran J. |title=Pools and Spas |year=2011 |publisher=Creative Homeowner |location=Upper Saddle River, New Jersey |isbn=978-1-58011-533-9 |author2=David Short}}</ref><ref>{{cite web |title=Controlling Chloramines in Indoor Swimming Pools |url=http://www0.health.nsw.gov.au/factsheets/environmental/control_chloramines.html |publisher=NSW Government |accessdate=2013-02-15 |url-status=dead |archiveurl=https://web.archive.org/web/20110403074224/http://www.health.nsw.gov.au/factsheets/environmental/control_chloramines.html |archivedate=2011-04-03}}</ref> Some pool test kits designed for use by homeowners do not distinguish free chlorine and chloramines, which can be misleading and lead to non-optimal levels of chloramines in the pool water.<ref>{{cite web |url=http://intothebluesrq.com/newsletter/ |title=Pool Service Information |last=Hale|first=Chris |date=20 April 2016 |website=Into The Blue Pools |access-date=22 April 2016}}</ref> |
|
|
There is also evidence that exposure to chloramine can contribute to ]s, including ], among ].<ref>{{cite journal |first=Valérie |last=Bougault |title=The Respiratory Health of Swimmers |journal=Sports Medicine |volume=39 |issue=4 |pages=295–312 |date=2009 |doi=10.2165/00007256-200939040-00003|pmid=19317518 |s2cid=26017985 |display-authors=etal}}</ref> Respiratory problems related to chloramine exposure are common and prevalent among competitive swimmers.<ref>{{cite journal|title=The determinants of prevalence of health complaints among young competitive swimmers |journal=International Archives of Occupational and Environmental Health |volume=80 |issue=1 |pages=32–39 |date=2006-10-01 |doi=10.1007/s00420-006-0100-0|pmid=16586082 |last1=Lévesque |first1=Benoit |last2=Duchesne |first2=Jean-François |last3=Gingras |first3=Suzanne |last4=Lavoie |first4=Robert |last5=Prud'Homme |first5=Denis |last6=Bernard |first6=Emmanuelle |last7=Boulet |first7=Louis-Philippe |last8=Ernst |first8=Pierre |bibcode=2006IAOEH..80...32L |s2cid=21688495}}</ref> |
|
|
|
|
|
Though chloramine's distinctive smell has been described by some as pleasant and even nostalgic,<ref>{{Cite web|date=2016-08-22|title=The smell of chlorine: nostalgic or noxious?|url=https://rheemthermal.com.au/blog/health-and-safety/the-smell-of-chlorine-nostalgic-or-noxious/|access-date=2020-11-22|website=Rheem Thermal Swimming Pool Heating|language=en-US}}</ref> its formation in pool water as a result of bodily fluids being exposed to chlorine can be minimised by encouraging ]ing and other hygiene methods prior to entering the pool,<ref>{{Cite web|title=Chloramines: Understanding "Pool Smell"|url=https://chlorine.americanchemistry.com/Science-Center/Chlorine-Compound-of-the-Month-Library/Chloramines-Understanding-Pool-Smell/|access-date=2020-11-22|website=chlorine.americanchemistry.com}}</ref> as well as refraining from swimming while suffering from digestive illnesses and taking breaks to use the bathroom, instead of simply urinating in the pool.<ref>{{Cite web|title=The Chlorine Smell From Pools May Actually Indicate Bodily Fluids Mixed In The Water, According To The CDC|url=https://www.bustle.com/p/the-chlorine-smell-from-pools-may-actually-indicate-bodily-fluids-mixed-in-the-water-according-to-the-cdc-17989837|access-date=2020-11-22|website=Bustle|language=en}}</ref><ref>{{Cite web|date=2019-05-15|title=Chemical Irritation of the Eyes and Lungs {{!}} Healthy Swimming {{!}} Healthy Water {{!}} CDC|url=https://www.cdc.gov/healthywater/swimming/swimmers/rwi/chemical-irritants.html|access-date=2020-11-22|website=www.cdc.gov|language=en-us}}</ref> |
|
|
|
|
|
==Safety== |
|
|
US EPA ] limit chloramine concentration for public water systems to 4 ] (ppm) based on a running annual average of all samples in the distribution system. In order to meet EPA-regulated limits on halogenated ]s, many utilities are switching from ] to ]. While chloramination produces fewer regulated total halogenated disinfection by-products, it can produce greater concentrations of unregulated iodinated disinfection byproducts and ].<ref>{{cite journal |title=Occurrence of a New Generation of Disinfection Byproducts |year=2006 |last1=Krasner |first1= Stuart W. |last2=Weinberg |first2=Howard S. |last3=Richardson |first3=Susan D. |last4=Pastor |first4=Salvador J. |last5=Chinn |first5=Russell |last6=Sclimenti |first6=Michael J. |last7=Onstad |first7=Gretchen D. |last8=Thruston |first8=Alfred D. |journal= Environmental Science & Technology |volume=40 |issue=23 |pages=7175–7185 |doi=10.1021/es060353j|pmid=17180964 |s2cid=41960634}}</ref><ref name=Richardson07>{{cite journal |title=Occurrence, genotoxicity, and carcinogenicity of regulated and emerging disinfection by-products in drinking water: A review and roadmap for research |year=2007 |last1=Richardson |first1=Susan D. |last2=Plewa |first2=Michael J. |last3=Wagner |first3=Elizabeth D. |last4=Schoeny |first4=Rita |last5=DeMarini |first5=David M. |journal=Mutation Research/Reviews in Mutation Research |volume=636 |issue=1–3 |pages=178–242 |pmid=17980649 |doi=10.1016/j.mrrev.2007.09.001|bibcode=2007MRRMR.636..178R }}</ref> Both iodinated disinfection by-products and ''N''-nitrosodimethylamine have been shown to be ], causing damage to the genetic information within a cell resulting in ] which may lead to ].<ref name=Richardson07/> |
|
|
|
|
|
Another newly-identified byproduct of chloramine is ], whose toxicity has not yet been determined.<ref name=":1">{{Cite news |last1=Achenbach |first1=Joel |last2=Johnson |first2=Carolyn Y. |date=2024-11-21 |title=Mysterious chemical byproduct in U.S. tap water finally identified |url=https://www.washingtonpost.com/science/2024/11/21/tap-water-byproduct-chloronitramide-anion/ |access-date=2024-11-22 |newspaper=]}}</ref> |
|
|
|
|
|
===Lead poisoning incidents=== |
|
|
In the year 2000, ], switched from chlorine to monochloramine, causing lead to leach from unreplaced pipes. The number of babies with elevated blood lead levels rose about tenfold, and by one estimate fetal deaths rose between 32% and 63%.<ref name="find_them">{{cite news |title='Time bomb' lead pipes will be removed. But first water utilities have to find them |url=https://www.npr.org/sections/health-shots/2022/07/20/1112049811/lead-pipe-removal |date=July 20, 2022 |agency=Midwest Newsroom |author=Allison Kite |publisher=]}}</ref> |
|
|
|
|
|
] made the same switch, causing about one quarter of tested households to exceed EPA drinking water lead limits in the period from 2017 to 2019. 20 children tested positive for lead poisoning in 2016 alone.<ref name="find_them" /> In 2023, ] Professor Marc Edwards said lead spikes occur in several water utility system switchovers per year, due to lack of sufficient training and lack of removal of lead pipes.<ref name="find_them" /> Lack of utility awareness that lead pipes are still in use is also part of the problem; the EPA has required all water utilities in the United States to prepare a complete lead pipe inventory by October 16, 2024.<ref>{{Cite web|url=https://www.epa.gov/ground-water-and-drinking-water/lead-and-copper-rule-improvements|title=Lead and Copper Rule Improvements|date=4 May 2022 }}</ref> |
|
|
|
|
|
==Synthesis and chemical reactions== |
|
==Synthesis and chemical reactions== |
|
NH<sub>2</sub>Cl is a highly unstable compound in concentrated form. Pure NH<sub>2</sub>Cl decomposes violently above −40 °C.<ref>Holleman, A. F.; Wiberg, E. "Inorganic Chemistry" Academic Press: San Diego, 2001. ISBN 0-12-352651-5.</ref> NH<sub>2</sub>Cl is, however, quite stable in dilute solution, and this considerable stability is the basis of its applications. |
|
Chloramine is a highly unstable compound in concentrated form. Pure chloramine decomposes violently above {{cvt|−40|°C}}.<ref>Holleman, A. F.; Wiberg, E. "Inorganic Chemistry" Academic Press: San Diego, 2001. {{ISBN|0-12-352651-5}}.</ref> Gaseous chloramine at low pressures and low concentrations of chloramine in aqueous solution are thermally slightly more stable. Chloramine is readily soluble in water and ], but less soluble in ] and ].<ref name="eoic">{{citation | first1=Anton | last1=Hammerl | first2=Thomas M. | last2=Klapötke | contribution=Nitrogen: Inorganic Chemistry | title=Encyclopedia of Inorganic Chemistry | edition=2nd | publisher=Wiley | year=2005 | pages=55–58}}</ref> |
|
|
|
|
|
|
=== Production === |
|
NH<sub>2</sub>Cl is prepared by the ] between ] and ]<ref name=ref29>Fair, G. M., J. C. Morris, S. L. Chang, I. Weil, and R. P. Burden. 1948. The behavior of chlorine as a water disinfectant. J. Am. Water Works Assoc. 40:1051-1061.</ref> under mildly alkaline conditions: |
|
|
|
In dilute aqueous solution, chloramine is prepared by the reaction of ] with ]:<ref name="eoic" /> |
|
:NH<sub>3</sub> + HOCl → NH<sub>2</sub>Cl + H<sub>2</sub>O |
|
|
|
: NH<sub>3</sub> + NaOCl → NH<sub>2</sub>Cl + NaOH |
|
The synthesis is conducted in dilute solution. In this reaction HOCl undergoes attack by the ] NH<sub>3</sub>. At a lower pH, further chlorination occurs. |
|
|
|
|
|
|
|
This reaction is also the first step of the ] for ] synthesis. The reaction has to be carried out in a slightly alkaline medium (] 8.5–11). The acting chlorinating agent in this reaction is ] (HOCl), which has to be generated by ] of ], and then reacts in a ] of the ] against the ]. The reaction occurs quickest at around pH 8. At higher pH values the concentration of hypochlorous acid is lower, at lower pH values ammonia is protonated to form ]s ({{chem|NH|4|+}}), which do not react further. |
|
===Laboratory methods=== |
|
|
The above syntheses are useful but do not deliver NH<sub>2</sub>Cl in pure form. For research purposes, the pure compound can be prepared by contacting ] with ]: |
|
|
:NH<sub>2</sub>F + CaCl<sub>2</sub> → NH<sub>2</sub>Cl + CaClF |
|
|
|
|
|
|
|
The chloramine solution can be concentrated by ] and by passing the vapor through ] which absorbs the water. Chloramine can be extracted with ether. |
|
==Uses and chemical reactions== |
|
|
NH<sub>2</sub>Cl is a key intermediate in the traditional synthesis of ]. |
|
|
|
|
|
|
|
Gaseous chloramine can be obtained from the reaction of gaseous ammonia with ] gas (diluted with ] gas): |
|
Monochloramine oxidizes sulfhydryls and disulfides in the same manner as HClO,<ref name=ref46>Jacangelo, J. G., V. P. Olivieri, and K. Kawata. 1987. Oxidation of sulfhydryl groups by monochloramine. Water Res. 21:1339-1344.</ref> but only possesses 0.4% of the biocidal effect of HClO.<ref name=ref64>Morris, J. C. 1966. Future of chlorination. J. Am. Water Works Assoc. 58:1475-1482.</ref> |
|
|
|
: 2 NH<sub>3</sub> + Cl<sub>2</sub> {{eqm}} NH<sub>2</sub>Cl + ] |
|
|
|
|
|
|
Pure chloramine can be prepared by passing ] through ]: |
|
==Reduction of organic chloramines== |
|
|
|
: 2 NH<sub>2</sub>F + CaCl<sub>2</sub> → 2 NH<sub>2</sub>Cl + ] |
|
Chloramines are often an unwanted side product of oxidation reactions of organic compounds (with amino groups) with ]. The reduction of chloramines back into amines can be carried out through a mild hydride donor. ] will reduce chloramines, but this reaction is greatly sped up with acid catalysis. |
|
|
|
|
|
|
|
=== Decomposition === |
|
==Uses in water treatment== |
|
|
|
The ] N−Cl bonds of chloramines are readily ] with release of ]:<ref name="ueoic">{{Ullmann | first1=Yasukazu | last1=Ura | first2=Gozyo | last2=Sakata | title=Chloroamines | year=2007 | page=5}}</ref> |
|
NH<sub>2</sub>Cl is commonly used in low ]s as a secondary ] in ]s as an alternative to free chlorine ]. This application is increasing. ] (sometimes referred to as '''free chlorine''') is being displaced by chloramine, which is much more stable and does not dissipate from the ] before it reaches consumers. NH<sub>2</sub>Cl also has a very much lower, however still present, tendency than free chlorine to convert organic materials into ]s such as ] and ]. Such compounds have been identified as ]s and in 1979 the ] began regulating their levels in U.S. drinking water. Furthermore, water treated with chloramine lacks the distinct chlorine odour of the gaseous treatment and so has improved taste. In swimming pools, chloramines are formed by the reaction of free chlorine with organic substances. Chloramines, compared to free chlorine, are both less effective as a sanitizer and more irritating to the eyes of swimmers. When swimmers complain of eye irritation from "too much chlorine" in a pool, the problem is typically a high level of chloramines.{{fact|date=April 2009}} Pool test kits designed for use by homeowners are sensitive to both free chlorine and chloramines, which can be misleading.{{fact|date=April 2009}} |
|
|
|
: RR′NCl + H<sub>2</sub>O {{eqm}} RR′NH + HOCl |
|
|
|
|
|
|
The quantitative ] (''K'' value) is used to express the ] power of chloramines, which depends on their generating hypochlorous acid in water. It is expressed by the equation below, and is generally in the range 10<sup>−4</sup> to 10<sup>−10</sup> ({{val|2.8|e=-10}} for monochloramine): |
|
] Chloramine-treated water has a greenish cast, the source of the colour is uncertain. Pure water by contrast normally is clear. This greenish color may be observed by filling a white polyethylene bucket with chloraminated tap water and comparing it to chloramine-free water such as distilled water or a sample from a swimming pool. |
|
|
|
|
|
|
|
: <math>K = \frac{ c_{\text{RR}'\text{NH}} \cdot c_\text{HOCl} }{ c_{\text{RR}'\text{NCl}} }</math> |
|
===Health risks=== |
|
|
Adding chloramine to the water supply can increase exposure to lead in drinking water, especially in areas with older housing; this exposure can result in increased lead levels in the bloodstream and can pose a significant health risk.<ref></ref> |
|
|
|
|
|
|
|
In aqueous solution, chloramine slowly decomposes to ] and ] in a neutral or mildly alkaline (pH ≤ 11) medium: |
|
There is also evidence that exposure to chloramine can contribute to respiratory problems, including ], among ].<ref></ref> Respiratory problems related to chloramine exposure are common and prevalent among competitive swimmers.<ref></ref> |
|
|
|
|
|
|
|
: 3 NH<sub>2</sub>Cl → N<sub>2</sub> + NH<sub>4</sub>Cl + 2 HCl |
|
Chloramine use, together with ], ], and ], has been described as a public health concern and an example of the outcome of poorly implemented environmental regulation. These methods of disinfection decrease the formation of regulated byproducts, which has led to their widespread use. However, they can increase the formation of a number of unregulated cytotoxic and genotoxic byproducts, some of which pose greater health risks than the regulated chemicals,<ref></ref> causing such diseases as cancer, kidney disease, thyroid damage,<ref></ref>and birth defects.<ref></ref>. |
|
|
|
|
|
|
|
However, only a few percent of a 0.1 ] chloramine solution in water decomposes according to the formula in several weeks. At pH values above 11, the following reaction with ]s slowly occurs: |
|
===Removing chloramine from water=== |
|
|
|
|
|
|
|
: 3 NH<sub>2</sub>Cl + 3 OH<sup>−</sup> → NH<sub>3</sub> + N<sub>2</sub> + 3 Cl<sup>−</sup> + 3 H<sub>2</sub>O |
|
Chloramine can be removed from tap water by treatment with superchlorination (10 ppm or more of free chlorine, such as from a dose of sodium hypochlorite bleach or pool sanitizer) while maintaining a pH of about 7 (such as from a dose of hydrochloric acid). Hypochlorous acid from the free chlorine strips the ammonia from the chloramine, and the ammonia outgasses from the surface of the bulk water. This process takes about 24 hours for normal tap water concentrations of a few ppm of chloramine. Residual free chlorine can then be removed by exposure to bright sunlight for about 4 hours. |
|
|
|
|
|
|
|
In an acidic medium at pH values of around 4, chloramine ] to form ], which in turn disproportionates again at pH values below 3 to form ]: |
|
==Situations where NH<sub>2</sub>Cl is removed from water supplies== |
|
|
Many animals are sensitive to chloramine and it must be removed from water given to many animals in zoos. ] owners remove the chloramine from their ] because it is ] to ]. Aging the ] for a few days removes ] but not the more stable chloramine, which can be neutralised using products available at pet stores. |
|
|
|
|
|
|
|
: 2 NH<sub>2</sub>Cl + H<sup>+</sup> {{eqm}} NHCl<sub>2</sub> + {{chem|NH|4|+}} |
|
Chloramine must also be removed from the water prior to use in ] machines, as it would come in contact with the bloodstream across a permeable membrane. However, since chloramine is neutralized by the digestive process, kidney dialysis patients can still safely drink chloramine-treated water. |
|
|
|
: 3 NHCl<sub>2</sub> + H<sup>+</sup> {{eqm}} 2 NCl<sub>3</sub> + {{chem|NH|4|+}} |
|
|
|
|
|
|
At low pH values, nitrogen trichloride dominates and at pH 3–5 dichloramine dominates. These equilibria are disturbed by the irreversible decomposition of both compounds: |
|
] use reducing agents such as ] or ] to remove chloramine from brewing liquor as it, like ], it can be removed by boiling, however boil time to reduce chloramine to a terminal measurement is longer<ref></ref>. Residual sodium can cause off flavors in beer (See Brewing, Michael Lewis) so potassium metabisulfite is preferred. |
|
|
|
|
|
|
|
: NHCl<sub>2</sub> + NCl<sub>3</sub> + 2 H<sub>2</sub>O → N<sub>2</sub> + 3 HCl + 2 HOCl |
|
Chloramine can be removed from bathwater and birthing tubs by adding 1000 mg of vitamin C (as the ascorbic acid form) to a medium size bathtub (about 40 gallons of water).<ref></ref> |
|
|
|
|
|
|
==Organic chloramines== |
|
=== Reactions === |
|
|
In water, chloramine is pH-neutral. It is an ] (acidic solution: {{nowrap|1=] = +1.48 V}}, in basic solution {{nowrap|1=''E''° = +0.81 V}}):<ref name="eoic" /> |
|
A variety of organic chloramines are known and proven useful in ]. One example is ''N''-chloromorpholine ClN(CH<sub>2</sub>CH<sub>2</sub>)<sub>2</sub>O, ''N''-chloro], and ''N''-chloro] chloride.<ref>Lindsay Smith, J. R.; McKeer, L. C.; Taylor, J. M. "4-Chlorination of Electron-Rich Benzenoid Compounds: 2,4-Dichloromethoxybenzene" Organic Syntheses, CollectedVolume 8, p.167 (1993)..http://www.orgsyn.org/orgsyn/pdfs/CV8P0167.pdf describes several N-chloramines</ref> |
|
|
|
|
|
|
|
: NH<sub>2</sub>Cl + 2 H<sup>+</sup> + 2 ] → {{chem|NH|4|+}} + Cl<sup>−</sup> |
|
==Safety== |
|
|
|
|
|
NH<sub>2</sub>Cl is toxic in concentrated form.<ref></ref> US EPA regulations limit chloramine concentration to 4 ] (ppm). A typical target level in US public water supplies is 3 ppm. In order to meet EPA regulated limits on halogenated ], many utilities are switching from chlorination to chloramination. While chloramination produces fewer total halogenated ], it produces greater concentrations of unregulated iodinated ] and ].<ref>Occurrence of a New Generation of Disinfection Byproducts† Stuart W. Krasner,,, Howard S. Weinberg,, Susan D. Richardson,, Salvador J. Pastor,, Russell Chinn,, Michael J. Sclimenti,, Gretchen D. Onstad, and, Alfred D. Thruston, Jr. Environmental Science & Technology 2006 40 (23), 7175-7185 http://dx.doi.org/10.1021/es060353j </ref><ref>{{cite pmid|17980649}}</ref>. Both iodinated ] and ] have been shown to be genotoxic.<ref>{{cite pmid|17980649}}</ref> |
|
|
|
Reactions of chloramine include ], ], and ] of chlorine, electrophilic substitution of hydrogen, and ]s. |
|
|
|
|
|
Chloramine can, like hypochlorous acid, donate positively charged chlorine in reactions with ]s (Nu<sup>−</sup>): |
|
|
|
|
|
: Nu<sup>−</sup> + NH<sub>3</sub>Cl<sup>+</sup> → NuCl + NH<sub>3</sub> |
|
|
|
|
|
Examples of chlorination reactions include transformations to dichloramine and nitrogen trichloride in acidic medium, as described in the decomposition section. |
|
|
|
|
|
Chloramine may also aminate nucleophiles (]): |
|
|
|
|
|
: Nu<sup>−</sup> + NH<sub>2</sub>Cl → NuNH<sub>2</sub> + Cl<sup>−</sup> |
|
|
|
|
|
The amination of ammonia with chloramine to form hydrazine is an example of this mechanism seen in the Olin Raschig process: |
|
|
|
|
|
: NH<sub>2</sub>Cl + NH<sub>3</sub> + NaOH → N<sub>2</sub>H<sub>4</sub> + NaCl + H<sub>2</sub>O |
|
|
|
|
|
Chloramine electrophilically aminates itself in neutral and alkaline media to start its decomposition: |
|
|
|
|
|
: 2 NH<sub>2</sub>Cl → N<sub>2</sub>H<sub>3</sub>Cl + HCl |
|
|
|
|
|
The ] (N<sub>2</sub>H<sub>3</sub>Cl) formed during self-decomposition is unstable and decomposes itself, which leads to the net decomposition reaction: |
|
|
|
|
|
: 3 NH<sub>2</sub>Cl → N<sub>2</sub> + NH<sub>4</sub>Cl + 2 HCl |
|
|
|
|
|
Monochloramine oxidizes ]s and ] in the same manner as hypochlorous acid,<ref name=ref46>{{cite journal|last1=Jacangelo|first1=J. G.|first2=V. P.|last2=Olivieri|first3=K.|last3=Kawata|date=1987|title=Oxidation of sulfhydryl groups by monochloramine|journal=Water Res.|volume=21|issue=11|pages=1339–1344|doi=10.1016/0043-1354(87)90007-8|bibcode=1987WatRe..21.1339J }}</ref> but only possesses 0.4% of the biocidal effect of HClO.<ref name=ref64>{{cite journal|last=Morris|first=J. C.|date=1966|title=Future of chlorination|journal=J. Am. Water Works Assoc.|volume=58|issue=11|pages=1475–1482|doi=10.1002/j.1551-8833.1966.tb01719.x|bibcode=1966JAWWA..58k1475M }}</ref> |
|
|
|
|
|
==See also== |
|
|
* ] |
|
|
* ] |
|
|
* ] |
|
|
* ] |
|
|
* ] |
|
|
|
|
|
==References== |
|
==References== |
|
{{reflist}} |
|
{{Reflist|2}} |
|
|
|
|
|
==External links== |
|
==External links== |
|
|
* |
|
* |
|
|
|
* |
|
* |
|
|
|
* |
|
* |
|
|
|
* |
|
* |
|
|
* |
|
|
|
|
|
|
|
{{Nitrogen compounds}} |
|
|
|
|
|
] |
|
] |
|
] |
|
] |
|
|
] |
|
|
] |
|
|
] |
|
] |
|
|
] |
|
|
|
|
|
] |
|
] |
|
|
] |
|
|
] |
|
|
] |
|
|
] |
|
|
] |
|
|
] |
|
|
] |
|
|
] |
|
|
] |
|
|
] |
|
|
] |
|