2,3-Dichloro-5,6-dicyano-1,4-benzoquinone

2,3-Dichloro-5,6-dicyano-1,4-benzoquinone

Names
Preferred IUPAC name 4,5-Dichloro-3,6-dioxocyclohexa-1,4-diene-1,2-dicarbonitrile
Other names 2,3-Dichloro-5,6-dicyano-p-benzoquinone 4,5-Dichloro-3,6-dioxo-1,4-cyclohexadiene-1,2-dicarbonitrile Dichlorodicyanobenzoquinone
Identifiers
CAS Number	84-58-2 Y
3D model (JSmol)	Interactive image
Abbreviations	DDQ
ChemSpider	6517 Y
ECHA InfoCard	100.001.402
EC Number	201-542-2
PubChem CID	6775
RTECS number	GU4825000
InChI InChI=1S/C8Cl2N2O2/c9-5-6(10)8(14)4(2-12)3(1-11)7(5)13 Y Key: HZNVUJQVZSTENZ-UHFFFAOYSA-N Y InChI=1/C8Cl2N2O2/c9-5-6(10)8(14)4(2-12)3(1-11)7(5)13 Key: HZNVUJQVZSTENZ-UHFFFAOYAL
SMILES ClC=1C(=O)C(\C#N)=C(\C#N)C(=O)C=1Cl
Properties
Chemical formula	C8Cl2N2O2
Molar mass	227.00 g·mol−1
Appearance	yellow to orange powder
Density	1.7g/cm3
Melting point	210 to 215 °C (410 to 419 °F; 483 to 488 K) (decomposes)
Boiling point	301.8 °C (575.2 °F; 575.0 K) at 760mmHg
Solubility in water	reacts
Hazards
R-phrases (outdated)	R25 R29
S-phrases (outdated)	S22 S24/25 S37 S45
Flash point	136.3 °C (277.3 °F; 409.4 K)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Y  (what is YN ?)
Infobox references

2,3-Dichloro-5,6-dicyano-1,4-benzoquinone (or DDQ) is the chemical reagent with formula C₆Cl₂(CN)₂O₂. This oxidant is useful for the dehydrogenation of alcohols, phenols, and steroid ketones in organic chemistry. DDQ decomposes in water, but is stable in aqueous mineral acid.

Synthesis of DDQ involves cyanation of chloranil. Thiele and Günther first reported a 6-step preparation in 1906. The substance did not receive interest until its potential as a dehydrogenation agent was discovered. A single-step chlorination from 2,3-dicyanohydroquinone was reported in 1965.

The reagent removes pairs of H atoms from organic molecules. The stoichiometry of its action is illustrated by the conversion of tetralin to naphthalene:

The resulting hydroquinone is poorly soluble in typical reaction solvents (dioxane, alkanes), which facilitates workup.

DDQ reacts with water with release of hydrogen cyanide (HCN), which is highly toxic. A low-temperature and weakly acidic environment increases the stability of DDQ.