Chloranil

Chloranil^[1]
Names
	IUPAC name 2,3,5,6-Tetrachlorocyclohexa-2,5-diene-1,4-dione
	Other names p-Chloranil; Tetrachloro-1,4-benzoquinone; Tetrachloro-p-benzoquinone
Identifiers
CAS Number	118-75-2 ;
3D model (JSmol)	Interactive image;
ChEBI	CHEBI:36703 ;
ChEMBL	ChEMBL192627 ;
ChemSpider	8068 ;
ECHA InfoCard	100.003.887
EC Number	204-274-4;
KEGG	C18933 ;
PubChem CID	8371;
RTECS number	DK6825000;
UNII	01W5X7N5XV ;
CompTox Dashboard (EPA)	DTXSID2020266 ;
	InChI InChI=1S/C6Cl4O2/c7-1-2(8)6(12)4(10)3(9)5(1)11 Key: UGNWTBMOAKPKBL-UHFFFAOYSA-N ; InChI=1/C6Cl4O2/c7-1-2(8)6(12)4(10)3(9)5(1)11 Key: UGNWTBMOAKPKBL-UHFFFAOYAV;
	SMILES ClC=1C(=O)C(\Cl)=C(\Cl)C(=O)C=1Cl;
Properties
Chemical formula	C6Cl4O2
Molar mass	245.86 g·mol−1
Appearance	Yellow solid
Melting point	295 to 296 °C (563 to 565 °F; 568 to 569 K)
Magnetic susceptibility (χ)	-112.6·10−6 cm3/mol
Hazards
	GHS labelling:
Pictograms
Signal word	Warning
Hazard statements	H315, H319, H410
Precautionary statements	P264, P273, P280, P302+P352, P305+P351+P338, P321, P332+P313, P337+P313, P362, P391, P501
	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

Chloranil is a quinone with the molecular formula C₆Cl₄O₂. Also known as tetrachloro-1,4-benzoquinone, it is a yellow solid. Like the parent benzoquinone, chloranil is a planar molecule^[2] that functions as a mild oxidant.

Synthesis and use as reagent

Chloranil is produced by chlorination of phenol to give hexachlorocyclohexa-2,5-dien-1-one ("hexachlorophenol"). Hydrolysis of the dichloromethylene group in this dienone gives chloranil:^[3]

C₆H₅OH + 6 Cl₂ → C₆Cl₆O + 6 HCl

C₆Cl₆O + H₂O → C₆Cl₄O₂ + 2 HCl

Chloroanil serves as a hydrogen acceptor. It is more electrophilic than quinone itself. It is used for the aromatization reactions, such as the conversion of cyclohexadienes to the benzene derivatives.^[4]

Chloranil is used to test for free secondary amines. This test is useful for checking for the presence of proline derivatives. It is also a good test for the successful deprotection of a secondary amine. Secondary amines react with chloranil to give a brown/red/orange derivative, the colour depending on the amine. In these reactions, the amine displaces chloride from the ring of the quinone.

Commercial applications

It is a precursor to many dyes, such as pigment violet 23 and diaziquone (AZQ), a cancer chemotherapeutic agent.

References

^ Chloranil at Sigma-Aldrich
^ J.-M. Lü, S. V. Rosokha, I. S. Neretin and J. K. Kochi, "Quinones as Electron Acceptors. X-Ray Structures, Spectral (EPR, UV-vis) Characteristics and Electron-Transfer Reactivities of Their Reduced Anion Radicals as Separated vs Contact Ion Pairs" Journal of the American Chemical Society 2006 128, 16708-16719.doi:10.1021/ja066471o
^ François Muller and Liliane Caillard "Chlorophenols" in Ullmann's Encyclopedia of Industrial Chemistry Wiley-VCH, Weinheim, 2011. doi:10.1002/14356007.a07_001.pub2
^ Derek R. Buckle "Chloranil" in Encyclopedia of Reagents for Organic Synthesis, 2001, John Wiley. doi:10.1002/047084289X.rc057

External links

Chloranil in the Pesticide Properties DataBase (PPDB)

[1] Chloranil at Sigma-Aldrich

[Kochi-2] J.-M. Lü, S. V. Rosokha, I. S. Neretin and J. K. Kochi, "Quinones as Electron Acceptors. X-Ray Structures, Spectral (EPR, UV-vis) Characteristics and Electron-Transfer Reactivities of Their Reduced Anion Radicals as Separated vs Contact Ion Pairs" Journal of the American Chemical Society 2006 128, 16708-16719.doi:10.1021/ja066471o

[3] François Muller and Liliane Caillard "Chlorophenols" in Ullmann's Encyclopedia of Industrial Chemistry Wiley-VCH, Weinheim, 2011. doi:10.1002/14356007.a07_001.pub2

[4] Derek R. Buckle "Chloranil" in Encyclopedia of Reagents for Organic Synthesis, 2001, John Wiley. doi:10.1002/047084289X.rc057

[1]

[2]

[3]

[4]

Synthesis and use as reagent

Commercial applications

See also

References

External links