4-Nitrochlorobenzene

4-nitrochlorobenzene
IUPAC name 1-Chloro-4-nitrobenzene
Other names 4-Chloro-1-nitrobenzene; 4-Chloronitrobenzene; p-Nitrochlorobenzene; PNCBO
Identifiers
CAS number	100-00-5 Y
ChemSpider	21106020 N
KEGG	C14456 N
Jmol-3D images	{{#if:C1=CC(=CC=C1[N+](=O)[O-])Cl|Image 1
SMILES C1=CC(=CC=C1[N+](=O)[O-])Cl
InChI InChI=1S/C6H4ClNO2/c7-5-1-3-6(4-2-5)8(9)10/h1-4H N Key: CZGCEKJOLUNIFY-UHFFFAOYSA-N N InChI=1/C6H4ClNO2/c7-5-1-3-6(4-2-5)8(9)10/h1-4H Key: CZGCEKJOLUNIFY-UHFFFAOYAO
Properties
Molecular formula	C6H4ClNO2
Molar mass	157.55 g mol−1
Appearance	Light yellow solid
Density	1.52 g/cm³ (20 °C)
Melting point	83.6 °C; 182.5 °F; 356.8 K
Boiling point	242.0 °C; 467.6 °F; 515.1 K
Solubility in water	Insoluble
Solubility in other solvents	Soluble in toluene, ether, acetone, hot ethanol
Hazards
MSDS	External MSDS
Flash point	12 °C; 54 °F; 285 K
N (verify) (what is: Y/N?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
Infobox references

4-Nitrochlorobenzene is the organic compound with the formula ClC₆H₄NO₂. It is a pale yellow solid. 4-Nitrochlorobenzene is a common intermediate in the production of a number of industrially useful compounds, including common antioxidants found in rubber. Other isomers with the formula ClC₆H₄NO₂ include 2-nitrochlorobenzene and 3-nitrochlorobenzene.

Preparation

4-Nitrochlorobenzene is prepared industrially by nitration of chlorobenzene:^[1]

ClC₆H₅ + HNO₃ → ClC₆H₄NO₂ + H₂O

This reaction affords both the 2- and the 4-nitro derivatives, in about a 1:2 ratio. These isomers are separated by distillation. 4-Nitrochlorobenzene was originally prepared by the nitration of 4-bromochlorobenzene by Holleman and coworkers.^[2]

Applications

4-Nitrochlorobenzene is an intermediate in the preparation of a variety of derivatives. Nitration gives 2,4-dinitrochlorobenzene, and 3,4-dichloronitrobenzene. Reduction with iron metal gives 4-chloroaniline. The electron-withdrawing nature of the appended nitro-group makes the benzene ring especially susceptible to nucleophilic aromatic substitution, unlike related chlorobenzene. Thus, the strong nucleophiles hydroxide, methoxide, and amide displace chloride to give respectively 4-nitrophenol, 4-nitroanisole, 4-nitroaniline. ^[1]

Another major use of 4-nitrochlorobenzene is its condensation with aniline to produce 4-nitrodiphenylamine. Reductive alkylation of the nitro group affords secondary aryl amines, which are useful antioxidants for rubber.

4-Nitrochlorobenzene is the precursor to the anti-leprosy drug Dapsone (4-[(4-aminobenzene)sulfonyl]aniline).^[1]

Safety

The National Institute for Occupational Safety and Health considers 4-nitrochlorobenzene as a potential occupational carcinogen that may be absorbed through the skin.^[3] The Occupational Safety and Health Administration set a permissible exposure limit of 1 mg/m³, while the American Conference of Governmental Industrial Hygienists recommends an airborne exposure limit of 0.64 mg/m³, over a time-weighted average of eight hours.^[4][5]

References