:2,4-Dinitrochlorobenzene
{{Redirect|DNCB|the Bucharest Ring Road in Romania|Centura București}}
{{Chembox
| Verifiedfields = changed
| Watchedfields = changed
| verifiedrevid = 477211218
| ImageFile=2,4-Dinitrochlorobenzene.svg
| ImageSize=130px
| ImageFile1 = 1-chloro-2,4-dinitrobenzene.JPG
| PIN = 1-Chloro-2,4-dinitrobenzene
| OtherNames = Dinitrochlorobenzene
Chlorodinitrobenzene
2,4-Dinitrochlorobenzene
2,4-Dinitrophenyl chloride
4-Chloro-1,3-dinitrobenzene
|Section1={{Chembox Identifiers
| Abbreviations = CDNB; DNCB
| CASNo_Ref = {{cascite|correct|CAS}}
| CASNo = 97-00-7
| UNII_Ref = {{fdacite|correct|FDA}}
| UNII = GE3IBT7BMN
| PubChem = 6
| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
| ChemSpiderID = 5
| EINECS = 202-551-4
| ChEBI_Ref = {{ebicite|changed|EBI}}
| ChEBI = 34718
| SMILES = c1cc(c(cc1[N+](=O)[O-])[N+](=O)[O-])Cl
| InChI = 1S/C6H3ClN2O4/c7-5-2-1-4(8(10)11)3-6(5)9(12)13/h1-3H
| InChIKey = VYZAHLCBVHPDDF-UHFFFAOYSA-N
}}
|Section2={{Chembox Properties
| C=6 | H=3 | Cl=1 | N=2 | O=4
| Formula =
| MolarMass =
| Appearance = yellow crystals
| Odor = almond-like
| Density = 1.6867 g/cm3
| MeltingPtC = 54
| BoilingPtC = 315
| Solubility = Insoluble{{cite web|title=1-Chloro-2,4-dinitrobenzene|url=http://www.sigmaaldrich.com/catalog/product/aldrich/138630?lang=en®ion=US|website=Sigma-Aldrich|access-date=8 September 2014}}
| SolubleOther = soluble in ether, benzene, CS2
| RefractIndex = 1.5857 (60 °C)
}}
|Section4={{Chembox Hazards
| MainHazards =
| FlashPt =
| AutoignitionPt =
| ExploLimits = 2–22%
| NFPA-H = 3 | NFPA-F = 1 | NFPA-R = 4
| LD50 = 1.07 g/kg (rat, oral)
}}
}}
2,4-Dinitrochlorobenzene (DNCB) is an organic compound with the chemical formula (O2N)2C6H3Cl. It is a yellow solid that is soluble in organic solvents. It is an intermediate for the industrial production of other compounds.{{cite encyclopedia|author=Gerald Booth|title=Nitro Compounds, Aromatic|encyclopedia=Ullmann's Encyclopedia of Industrial Chemistry|year=2007|publisher=Wiley-VCH|location=Weinheim|doi=10.1002/14356007.a17_411|isbn=978-3527306732}}
Preparation and reactions
DNCB is produced commercially by the nitration of p-nitrochlorobenzene with a mixture of nitric and sulfuric acids. Other methods afford the compound less efficiently include the chlorination of 1,3-dinitrobenzene, nitration of o-nitrochlorobenzene and the dinitration of chlorobenzene.{{cite web|title=Synthesis of 1-chloro-2,4-dinitrobenzene - F. Ullmann, Verlag S. Hirzel Leipzig, 1908 |url=https://organic-btc-ilmenau.jimdo.com/app/download/8980039020/1-Chlor-2%2C4-dinitrobenzol.pdf |access-date=19 May 2020 }}
By virtue of the two nitro substituents, the chloride in DNCB is particularly susceptible to nucleophilic substitution, at least relative to simple chlorobenzene. In this way, the compound is a precursor to many other compounds.{{cite journal |author=J. F. Bunnett, R. M. Conner|doi=10.15227/orgsyn.040.0034|title=2,4-Dinitroiodobenzene |journal=Organic Syntheses |year=1960 |volume=40 |page=34 }}{{cite journal |doi=10.15227/orgsyn.015.0022|title=2,4-Dinitroaniline |author=F. B. Wells, C. F. H. Allen|journal=Organic Syntheses |year=1935 |volume=15 |page=22 }}{{cite journal |doi=10.15227/orgsyn.044.0047|title=2,4-Dinitrobenzenesulfenyl Chloride |author=Norman Kharasch, Robert B. Langford|journal=Organic Syntheses |year=1964 |volume=44 |page=47 }} In one example, DNCB is as a substrate in Glutathione S-Transferase, relevant to activity assays.{{cite journal |vauthors=Habig WH, Pabst MJ, Jakoby WB | year = 1974 | title = Glutathione S-transferases. The first enzymatic step in mercapturic acid formation | journal = J Biol Chem | volume = 249 | pages = 7130–7139 | pmid = 4436300 | issue = 22| doi = 10.1016/S0021-9258(19)42083-8 | doi-access = free }}
Safety
DNCB induces a type IV hypersensitivity reaction in almost all people exposed to it, so it is used medically to assess the T cell activity in patients. This is a useful diagnostic test for immunocompromised patients. It can also be used to treat warts.{{cite web |url=http://www.health.harvard.edu/fhg/updates/update0303d.shtml |title=Treating warts |publisher=Harvard Medical School |access-date=April 2, 2010 |archive-url=https://web.archive.org/web/20101103023520/http://www.health.harvard.edu/fhg/updates/update0303d.shtml |archive-date=2010-11-03 |url-status=dead }}
DNCB can cause contact dermatitis.{{cite journal |vauthors=White SI, Friedmann PS, Moss C, Simpson JM |title=The effect of altering area of application and dose per unit area on sensitization by DNCB |journal=Br. J. Dermatol. |volume=115 |issue=6 |pages=663–8 |year=1986 |pmid=3801307 |doi= 10.1111/j.1365-2133.1986.tb06646.x|s2cid=21476276 }}
References
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