Chloranilic acid

Chloranilic acid ^[1]

Skeletal formula of chloranilic acid
Ball-and-stick model of chloranilic acid
Names
Preferred IUPAC name 2,5-Dichloro-3,6-dihydroxycyclohexa-2,5-diene-1,4-dione
Other names 2,5-Dichloro-3,6-dihydroxy-1,4-benzoquinone 2,5-Dichloro-3,6-dihydroxybenzoquinone
Identifiers
CAS Number	87-88-7
3D model (JSmol)	Interactive image
ChemSpider	59971
ECHA InfoCard	100.001.619
EC Number	201-780-7
PubChem CID	66604
UNII	YJ8L3BB7Y4
CompTox Dashboard (EPA)	DTXSID3058959
InChI InChI=1/C6H2Cl2O4/c7-1-3(9)5(11)2(8)6(12)4(1)10/h9,12H Key: IPPWILKGXFOXHO-UHFFFAOYAU
SMILES Cl\C1=C(/O)C(=O)C(\Cl)=C(\O)C1=O
Properties
Chemical formula	C6H2Cl2O4
Molar mass	208.98 g/mol
Appearance	orange or red crystals or powder
Density	1.96 g/cm3 [2]
Melting point	≥300 °C
Acidity (pKa)	2.95, 4.97 [3]
Hazards
GHS labelling:
Pictograms
Signal word	Warning
Hazard statements	H315, H319, H335
Precautionary statements	P261, P264, P271, P280, P302+P352, P304+P340, P305+P351+P338, P312, P321, P332+P313, P337+P313, P362, P403+P233, P405, P501
Flash point	135.4 °C (275.7 °F; 408.5 K)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Chloranilic acid is an organic compound with the chemical formula C₆Cl₂O₂(OH)₂. It is a red-orange solid. The compound is obtained by hydrolysis of chloranil:

C₆Cl₄O₂ + 2 H₂O → C₆Cl₂O₂(OH)₂ + 2 HCl

It is centrosymmetric, planar molecule. It also crystallizes as a dihydrate. ^[2]

Chloranilic acid is a noteworthy hydroxyquinone that is somewhat acidic owing to the presence of the two chloride substituents. The conjugate base, C₆H₂Cl₂O₄^2- readily forms coordination complexes often linking pairs of many metal ions. ^[3]

See also

• Chloranil

References

1. "Chloranilic acid". Sigma-Aldrich.
2. Andersen, E. K. (1967). "The Crystal and Molecular Structure of Hydroxyquinones and Salts of Hydroxyquinones. I. Chloranilic Acid". Acta Crystallographica. 22 (2): 188–191. doi: 10.1107/S0365110X67000325 .
3. Mostafa, S. I. (1999). "Complexes of 2,5-Dihydroxy-1,4-Benzoquinone and Chloranilic Acid with Second and Third Row Transition Elements". Transition Metal Chemistry. 24 (3): 306–310. doi:10.1023/A:1006944124791. S2CID   91429728.