2-Nitrochlorobenzene
{{Chembox
| ImageFile = 2-Chlornitrobenzol.svg
| ImageSize = 150px
| PIN = 1-Chloro-2-nitrobenzene
| OtherNames = 2-Chloronitrobenzene
|Section1={{Chembox Identifiers
| ChemSpiderID = 13853953
| SMILES = C1=CC=C(C(=C1)[N+](=O)[O-])Cl
| InChI = 1/C6H4ClNO2/c7-5-3-1-2-4-6(5)8(9)10/h1-4H
| InChIKey = BFCFYVKQTRLZHA-UHFFFAOYAA
| StdInChI = 1S/C6H4ClNO2/c7-5-3-1-2-4-6(5)8(9)10/h1-4H
| StdInChIKey = BFCFYVKQTRLZHA-UHFFFAOYSA-N
| CASNo = 88-73-3
| ChEBI = 34270
| PubChem = 6945
| EC_number = 201-854-9
| RTECS = CZ0875000
| UNNumber = 1578
| UNII = D1YI9R2K8O
| KEGG = C14407
| ChEMBL = 53330
}}
|Section2={{Chembox Properties
| Cl=1 | C=6 | H=4 | N=1 | O=2
| Appearance = Yellow crystals
| Density = 1.368 g/mL
| MeltingPtC = 33
| BoilingPtC = 245.5
| Solubility = Insoluble
| SolubleOther = Highly soluble in diethyl ether, benzene, and hot ethanol
| Solvent = other solvents
}}
|Section3={{Chembox Hazards
| GHSPictograms = {{GHS06}}{{GHS07}}{{GHS08}}{{GHS09}}
| GHSSignalWord = Danger
| HPhrases = {{H-phrases|301|302|311|312|317|331|332|350|351|361|372|411}}
| PPhrases = {{P-phrases|201|202|260|261|264|270|271|272|273|280|281|301+310|301+312|302+352|304+312|304+340|308+313|311|312|314|321|322|330|333+313|361|363|391|403+233|405|501}}
| MainHazards = Toxic, Irritant
| FlashPtC = 124
| AutoignitionPt = }}
}}
2-Nitrochlorobenzene is an organic compound with the formula ClC6H4NO2. It is one of three isomeric nitrochlorobenzenes.{{cite book|doi=10.1002/14356007.a17_411 |chapter=Nitro Compounds, Aromatic |title=Ullmann's Encyclopedia of Industrial Chemistry |date=2000 |last1=Booth |first1=Gerald |isbn=978-3-527-30385-4|publisher= Wiley-VCH|location=Weinheim}} It is a yellow crystalline solid that is important as a precursor to other compounds due to its two functional groups.
Synthesis
Nitrochlorobenzene is typically synthesized by nitration of chlorobenzene in the presence of sulfuric acid:
:C6H5Cl + HNO3 → O2NC6H4Cl + H2O
This reaction affords a mixture of isomers. Using an acid ratio of 30% nitric acid, 56% sulfuric acid and 14% water, the product mix is typically 34-36% 2-nitrochlorobenzene and 63-65% 4-nitrochlorobenzene, with only about 1% 3-nitrochlorobenzene.
Reactions
2-Nitrochlorobenzene can be reduced to the 2-chloroaniline with Fe/HCl mixture, the Bechamp reduction.
2-Nitrochlorobenzene, like its isomers, is reactive toward nucleophiles, resulting in chloride substitution. With polysulfide, it reacts to give di-orthonitrophenyl disulfide:{{cite journal |doi=10.15227/orgsyn.008.0064 |title=Di-o-Nitrophenyl Disulfide |journal=Organic Syntheses |year=1928 |volume=8 |page=64|first1= Marston T. |last1=Bogert|first2=Arthur|last2=Stull }}
:{{chem2|2 O2NC6H4Cl + Na2S2 -> (O2NC6H4S)2 + 2 NaCl}}
Similarly, it reacts with sodium methoxide to give 2-nitroanisole.
Substitution of chloride by fluoride is also practiced commercially to convert 2-nitrochlorobenzene to 2-fluoronitrobenzene. The Halex process uses potassium fluoride in polar solvents like sulfolane :
:{{chem2|O2NC6H4Cl + KF -> O2NC6H4F + KCl}}
Applications
2-Nitrochlorobenzene is useful because both of its reactive sites can be utilized to create further compounds that are mutually ortho. Its derivative 2-chloroaniline is a precursor to 3,3’-dichlorobenzidine, a precursor to dyes and pesticides.