4-Nitrochlorobenzene

4-nitrochlorobenzene

Skeletal formula of 4-nitrochlorobenzene Ball-and-stick model of the 4-nitrochlorobenzene molecule
Names
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
Jmol 3D model	Interactive image
KEGG	C14456 N
PubChem	7474
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
SMILES C1=CC(=CC=C1[N+](=O)[O-])Cl
Properties
Chemical formula	C6H4ClNO2
Molar mass	157.55 g·mol−1
Appearance	Light yellow solid
Odor	sweet
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
Vapor pressure	0.2 mmHg (30°C)
Vapor pressure	{{{value}}}
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N verify (what is YN ?)
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:

$\mathrm{ClC_6H_5 + HNO_3 \rightarrow ClC_6H_4NO_2 + H_2O}$

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.

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.

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).

Safety

The National Institute for Occupational Safety and Health considers 4-nitrochlorobenzene as a potential occupational carcinogen that may be absorbed through the skin. 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.