4-Nitrochlorobenzene

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4-nitrochlorobenzene
4-chloronitrobenzene.png
Identifiers
CAS number 100-00-5 YesY
ChemSpider 21106020 N
KEGG C14456 N
Jmol-3D images Image 1
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)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
 N (verify) (what is: YesY/N?)
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[edit]

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

 \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.[2]

Applications[edit]

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[edit]

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[edit]

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