Article · Wikipedia archive · Last revised Jul 17, 2026

2,4-Dinitrochlorobenzene

2,4-Dinitrochlorobenzene (DNCB) is an organic compound with the chemical formula (O2N)2C6H3Cl. It is a yellow solid that is soluble in organic solvents. It is an intermediate for the industrial production of other compounds.

Last revised
Jul 17, 2026
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Citations
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Wikipedia ↗
2,4-Dinitrochlorobenzene
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Names
Preferred IUPAC name
1-Chloro-2,4-dinitrobenzene
Other names
Dinitrochlorobenzene
Chlorodinitrobenzene
2,4-Dinitrochlorobenzene
2,4-Dinitrophenyl chloride
4-Chloro-1,3-dinitrobenzene
Identifiers
3D model (JSmol)
Abbreviations CDNB; DNCB
ChEBI
ChemSpider
ECHA InfoCard 100.002.321
EC Number
  • 202-551-4
UNII
  • InChI=1S/C6H3ClN2O4/c7-5-2-1-4(8(10)11)3-6(5)9(12)13/h1-3H
    Key: VYZAHLCBVHPDDF-UHFFFAOYSA-N
  • c1cc(c(cc1[N+](=O)[O-])[N+](=O)[O-])Cl
Properties
C6H3ClN2O4
Molar mass 202.55 g·mol−1
Appearance yellow crystals
Odor almond-like
Density 1.6867 g/cm3
Melting point 54 °C (129 °F; 327 K)
Boiling point 315 °C (599 °F; 588 K)
Insoluble1
Solubility soluble in ether, benzene, CS2
1.5857 (60 °C)
Hazards
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 3: Short exposure could cause serious temporary or residual injury. E.g. chlorine gasFlammability 1: Must be pre-heated before ignition can occur. Flash point over 93 °C (200 °F). E.g. canola oilInstability 4: Readily capable of detonation or explosive decomposition at normal temperatures and pressures. E.g. nitroglycerinSpecial hazards (white): no code
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3
1
4
Explosive limits 2–22%
Lethal dose or concentration (LD, LC):
1.07 g/kg (rat, oral)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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2,4-Dinitrochlorobenzene (DNCB) is an organic compound with the chemical formula (O2N)2C6H3Cl. It is a yellow solid that is soluble in organic solvents. It is an intermediate for the industrial production of other compounds.2

Preparation and reactions

DNCB is produced commercially by the nitration of p-nitrochlorobenzene with a mixture of nitric and sulfuric acids. Other methods afford the compound less efficiently include the chlorination of 1,3-dinitrobenzene, nitration of o-nitrochlorobenzene and the dinitration of chlorobenzene.3

By virtue of the two nitro substituents, the chloride in DNCB is particularly susceptible to nucleophilic substitution, at least relative to simple chlorobenzene. In this way, the compound is a precursor to many other compounds. For example, the chloride can be replaced by iodide easily.456

Reaction of DNCB with ammonia gives 2,4-dinitrochloroaniline, again a versatile precursor.2

DNCB is as a substrate in glutathione S-transferase, relevant to activity assays.7

Safety

DNCB induces a type IV hypersensitivity reaction in almost all people exposed to it, so it is used medically to assess the T cell activity in patients. This is a useful diagnostic test for immunocompromised patients. It can also be used to treat warts.8

DNCB can cause contact dermatitis.9

References

References

  1. "1-Chloro-2,4-dinitrobenzene". Sigma-Aldrich. Retrieved 8 September 2014.
  2. Gerald Booth (2007). "Nitro Compounds, Aromatic". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a17_411. ISBN 978-3527306732.
  3. "Synthesis of 1-chloro-2,4-dinitrobenzene - F. Ullmann, Verlag S. Hirzel Leipzig, 1908" (PDF). Retrieved 19 May 2020.
  4. J. F. Bunnett, R. M. Conner (1960). "2,4-Dinitroiodobenzene". Organic Syntheses. 40: 34. doi:10.15227/orgsyn.040.0034.
  5. F. B. Wells, C. F. H. Allen (1935). "2,4-Dinitroaniline". Organic Syntheses. 15: 22. doi:10.15227/orgsyn.015.0022.
  6. Norman Kharasch, Robert B. Langford (1964). "2,4-Dinitrobenzenesulfenyl Chloride". Organic Syntheses. 44: 47. doi:10.15227/orgsyn.044.0047.
  7. Habig WH, Pabst MJ, Jakoby WB (1974). "Glutathione S-transferases. The first enzymatic step in mercapturic acid formation". J Biol Chem. 249 (22): 7130–7139. doi:10.1016/S0021-9258(19)42083-8. PMID 4436300.
  8. "Treating warts". Harvard Medical School. Archived from the original on 2010-11-03. Retrieved April 2, 2010.
  9. White SI, Friedmann PS, Moss C, Simpson JM (1986). "The effect of altering area of application and dose per unit area on sensitization by DNCB". Br. J. Dermatol. 115 (6): 663–8. doi:10.1111/j.1365-2133.1986.tb06646.x. PMID 3801307. S2CID 21476276.