3,3'-Dichlorobenzidine

3,3'-Dichlorobenzidine^[1]
Names
	Preferred IUPAC name 3,3′-Dichloro[1,1′-biphenyl]-4,4′-diamine
	Other names 4-(4-Amino-3-chlorophenyl)-2-chloroaniline; 4,4′-Diamino-3,3′-dichlorobiphenyl; o,o'-Dichlorobenzidine; 3,3′-Dichlorobiphenyl-4,4′-diamine; 3,3′-Dichloro-4,4′-biphenyldiamine; 3,3′-Dichloro-4,4′-diaminobiphenyl
Identifiers
CAS Number	91-94-1 ;
3D model (JSmol)	Interactive image;
ChEMBL	ChEMBL314470 ;
ChemSpider	6803 ;
ECHA InfoCard	100.001.918
KEGG	C19225 ;
PubChem CID	7070;
UNII	1SDI2328UX ;
CompTox Dashboard (EPA)	DTXSID6020432 ;
	InChI InChI=1S/C12H10Cl2N2/c13-9-5-7(1-3-11(9)15)8-2-4-12(16)10(14)6-8/h1-6H,15-16H2 Key: HUWXDEQWWKGHRV-UHFFFAOYSA-N ; InChI=1/C12H10Cl2N2/c13-9-5-7(1-3-11(9)15)8-2-4-12(16)10(14)6-8/h1-6H,15-16H2 Key: HUWXDEQWWKGHRV-UHFFFAOYAF;
	SMILES Clc2cc(c1ccc(N)c(Cl)c1)ccc2N;
Properties
Chemical formula	C12H10Cl2N2
Molar mass	253.13 g/mol
Appearance	Gray or purple crystalline solid
Melting point	132 to 133 °C (270 to 271 °F; 405 to 406 K)
Boiling point	402 °C (756 °F; 675 K)
Solubility in water	0.07% (15°C)
Hazards
	Occupational safety and health (OHS/OSH):
Main hazards	Potential carcinogen
	NIOSH (US health exposure limits):
PEL (Permissible)	carcinogen
REL (Recommended)	Ca
IDLH (Immediate danger)	Ca [N.D.]
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). verify (what is ?) Infobox references

3,3'-Dichlorobenzidine is an organic compound with the formula (C₆H₃Cl(NH₂))₂. The pure compound is pale yellow, but commercial samples are often colored. It is barely soluble in water and is often supplied as a wet paste. It is widely used in the production of diarylide yellow pigments used in the production of printing inks.^[3] Its use in the production of dyes has been largely discontinued because of concerns about carcinogenicity.

Preparation and reactions

3,3'-Dichlorobenzidine is prepared in two steps from 2-nitrochlorobenzene. The first step involves reduction with zinc in base to afford 2,2'-dichlorodiphenylhydrazine. This intermediate undergoes the benzidine rearrangement to afford 3,3'-dichlorobenzidine.^[4]

Aqueous solutions of 3,3'-dichlorobenzidine degrade in light to monochloro derivative. It undergoes chlorination (for example in water treatment plants) to give the tetrachloro derivative.

The most widely practiced reaction of 3,3'-dichlorobenzidine is its double diazotization. This bis(diazo) intermediate is then coupled to derivatives of acetoacetylaminobenzene (CH₃C(O)CH₂C(O)NHAr). In this way, the following commercial yellow pigments are produced: pigment Yellow 12, pigment Yellow 13, pigment Yellow 14, pigment Yellow 17 and pigment Yellow 83.^[3]

C.I. Pigment Yellow 12, an industrially significant diarylide pigment, is produced via the diazonium derivative of 3,3'-dichlorobenzidine.

Safety

3,3'-Dichlorobenzidine is considered a carcinogen.^[1] This compound has been shown to increase the incidence of tumors in animals.^[5] Because it is structurally similar to benzidine, a known carcinogen, it is believed that it may share a similar mechanism in causing bladder cancer in humans.^[5]

References

^ ^a ^b Dichlorobenzidine - Compound Summary, PubChem.
^ ^a ^b ^c ^d ^e NIOSH Pocket Guide to Chemical Hazards. "#0191". National Institute for Occupational Safety and Health (NIOSH).
^ ^a ^b K. Hunger; W. Herbst (2012). "Pigments, Organic". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a20_371. ISBN 9783527303854.
^ Schwenecke, H.; Mayer, D. (2005). "Benzidine and Benzidine Derivatives". Ullmann’s Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a03_539. ISBN 9783527303854.
^ ^a ^b "3, 3'-Dichlorobenzidine". U.S. Environmental Protection Agency, Integrated Risk Information System. 7 March 2011. Accessed 3 May 2011.

External links

[pubchem-1] Dichlorobenzidine - Compound Summary, PubChem.

[PGCH-2] NIOSH Pocket Guide to Chemical Hazards. "#0191". National Institute for Occupational Safety and Health (NIOSH).

[Ullmann1-3] K. Hunger; W. Herbst (2012). "Pigments, Organic". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a20_371. ISBN 9783527303854.

[Ullmann-4] Schwenecke, H.; Mayer, D. (2005). "Benzidine and Benzidine Derivatives". Ullmann’s Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a03_539. ISBN 9783527303854.

[EPA-5] "3, 3'-Dichlorobenzidine". U.S. Environmental Protection Agency, Integrated Risk Information System. 7 March 2011. Accessed 3 May 2011.

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