CAS number 583-63-1
PubChem 11421
ChemSpider 10941 YesY
KEGG C02351 YesY
ChEBI CHEBI:17253 YesY
Jmol-3D images Image 1
Image 2
Molecular formula C6H4O2
Molar mass 108.0964 g/mol
Density 1.256 g/cm3
Boiling point

213.3 °C @760 mmHg

Flash point 76.4 °C
Related compounds
Related compounds 1,4-benzoquinone quinone
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Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

1,2-Benzoquinone, also called ortho-benzoquinone or cyclohexa-3,5-diene-1,2-dione, is a ketone, with formula C6H4O2. It is one of the two isomers of quinone, the other being 1,4-benzoquinone.

1,2-Benzoquinone is produced on oxidation of catechol exposed to air in aqueous solution[1][2] or by ortho oxidation of a phenol.[1] It is a precursor to melanin.[3] It is a red substance soluble in water and insoluble in ethyl ether.

A strain of the bacterium Pseudomonas mendocina metabolyzes benzoic acid yielding 1,2-benzoquinone (via cathecol) as the final product.[2]

See also

  • 1,4-Benzoquinone
  • Tetrabromo-1,2-benzoquinone (o-bromanil)
  • Tetrachloro-1,2-benzoquinone (o-chloranil)
  • Tetrahydroxy-1,2-benzoquinone
  • Hydroxybenzoquinone


  1. ^ a b Magdziak, D., Rodriguez, A. A.; Van De Water, R. W.; Pettus, T. R. R. (2002). "Regioselective oxidation of phenols to o-quinones with o-iodoxybenzoic acid (IBX)". Org. Lett. 4 (2): 285–288. doi:10.1021/ol017068j. PMC 1557836. PMID 11796071. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1557836. 
  2. ^ a b Chanda Parulekar and Suneela Mavinkurve (2006), Formation of ortho-benzoquinone from sodium benzoate by Pseudomonas mendocina P2d. Indian Journal of Experimental Biology, volume 44, pages 157--162. Online version accessed on 2010-02-04.
  3. ^ Enzymatic Browning in Fruits, Vegetables and Seafoods Section 2.3.2