4-Nitrochlorobenzene

4-nitrochlorobenzene

Names
Preferred IUPAC name 1-Chloro-4-nitrobenzene
Other names 4-Chloro-1-nitrobenzene 4-Chloronitrobenzene p-Nitrochlorobenzene PNCBO
Identifiers
CAS Number	100-00-5
3D model (Jmol)	Interactive image
ChemSpider	21106020
ECHA InfoCard	100.002.554
KEGG	C14456
PubChem	7474
UNII	CVL66U249D
InChI InChI=1S/C6H4ClNO2/c7-5-1-3-6(4-2-5)8(9)10/h1-4H Key: CZGCEKJOLUNIFY-UHFFFAOYSA-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[1]
Density	1.52 g/cm^3 (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)[1]
Hazards
Safety data sheet	External MSDS
Flash point	12 °C (54 °F; 285 K)
Lethal dose or concentration (LD, LC):
LD50 (median dose)	812 mg/kg (rat, oral) 1414 mg/kg (mouse, oral) 440 mg/kg (mouse, oral) 420 mg/kg (rat, oral)[1]
LC50 (median concentration)	164 mg/m^3 (cat, 7 hr)[1]
US health exposure limits (NIOSH):
PEL (Permissible)	TWA 1 mg/m^3 [skin][1]
REL (Recommended)	Ca[1]
IDLH (Immediate danger)	Ca [100 mg/m^3][1]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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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:^[2]

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

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.^[3]

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. ^[2]

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).^[2]

Safety

The National Institute for Occupational Safety and Health considers 4-nitrochlorobenzene as a potential occupational carcinogen that may be absorbed through the skin.^[4] 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.^[5][6]

References

1. "NIOSH Pocket Guide to Chemical Hazards #0452". National Institute for Occupational Safety and Health (NIOSH).
2. Gerald Booth "Nitro Compounds, Aromatic" in Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH: Weinheim, 2005. doi:10.1002/14356007.a17_411
3. "The nitration of mixed dihalogen benzenes" Recueil des Travaux Chimiques des Pays-Bas et de la Belgique. Amsterdam, 1915; pp. 204-235.
4. CDC - Immediately Dangerous to Life or Health Concentrations (IDLH): p-nitrochlorobenzene
5. CDC - NIOSH Pocket Guide to Chemical Hazards
6. New Jersey Department of Health and Senior Services - Hazardous Substance Fact Sheet