Chloranil
Chemical compound
From Wikipedia, the free encyclopedia
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[5] that functions as a mild oxidant.
| Names | |
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| IUPAC name
2,3,5,6-Tetrachlorocyclohexa-2,5-diene-1,4-dione | |
Other names
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| Identifiers | |
3D model (JSmol) |
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| ChEBI | |
| ChEMBL | |
| ChemSpider | |
| ECHA InfoCard | 100.003.887 |
| EC Number |
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| KEGG | |
PubChem CID |
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| RTECS number |
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| UNII | |
| UN number | 3077 |
CompTox Dashboard (EPA) |
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| Properties[1] | |
| C6Cl4O2 | |
| Molar mass | 245.86 g·mol−1 |
| Appearance | Yellow solid |
| Density | 1.97 g⋅cm−3[2] |
| Melting point | 298.3 °C (568.9 °F; 571.5 K) |
| Boiling point | Sublimes |
| 0.25 g/kg (20 °C (68 °F)) | |
| Solubility in Ethanol | Slightly soluble |
| Solubility in Chloroform | Slightly soluble |
| Solubility in Diethyl ether | Soluble |
| log P | 2.3 (20 °C (68 °F))[3] |
| Vapor pressure | 1 hPa (71 °C (160 °F))[2] |
| −112.6×10−6 cm3/mol[citation needed] | |
| Structure[4] | |
| Monoclinic | |
| P21/c (C5 2h) | |
| 2/m | |
a = 8.86 Å, b = 5.83 Å, c = 8.76 Å α = 90°, β = 72.6°, γ = 90° | |
Formula units (Z) |
2 |
| Hazards[3] | |
| GHS labelling: | |
| Danger | |
| H315, H317, H318, H410 | |
| P261, P264, P272, P273, P280, P302+P352, P305+P351+P338+P310, P333+P313, P362, P391, P501 | |
| NFPA 704 (fire diamond) | |
| Flash point | >100 °C (212 °F)[2] |
| >400 °C (752 °F) | |
| Lethal dose or concentration (LD, LC): | |
LD50 (median dose) |
4000 mg/kg (rat, oral) |
LC50 (median concentration) |
24.85 mg/m3 (rat, inhalation, 4h) |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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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:[6]
- 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.[7]
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.[citation needed]
Commercial applications
It is a precursor to many dyes, such as pigment violet 23 and diaziquone (AZQ), a cancer chemotherapeutic agent.[citation needed]

