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

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"DDQ" redirects here. DDQ is also the former callsign of a TV station in Toowoomba, Australia.
2,3-Dichloro-5,6-dicyano-1,4-benzoquinone[1]
Structural formula of dichlorodicyanobenzoquinone
Space-filling model of the dichlorodicyanobenzoquinone molecule
Names
Other names
  • 2,3-Dichloro-5,6-dicyano-p-benzoquinone
  • 4,5-Dichloro-3,6-dioxo-1,4-cyclohexadiene-1,2-dicarbonitrile
  • Dichlorodicyanobenzoquinone
Identifiers
84-58-2 YesY
Abbreviations DDQ
ChemSpider 6517 YesY
EC Number 201-542-2
Jmol 3D model Interactive image
PubChem 6775
RTECS number GU4825000
  • InChI=1S/C8Cl2N2O2/c9-5-6(10)8(14)4(2-12)3(1-11)7(5)13 YesY
    Key: HZNVUJQVZSTENZ-UHFFFAOYSA-N YesY
  • InChI=1/C8Cl2N2O2/c9-5-6(10)8(14)4(2-12)3(1-11)7(5)13
    Key: HZNVUJQVZSTENZ-UHFFFAOYAL
  • ClC=1C(=O)C(\C#N)=C(\C#N)C(=O)C=1Cl
Properties
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
reacts
Vapor pressure {{{value}}}
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
YesY verify (what is YesYN ?)
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,[2] phenols,[3] and steroid ketones[4] in organic chemistry. DDQ decomposes in water, but is stable in aqueous mineral acid.[5]

Preparation

Synthesis of DDQ involves cyanation of chloranil. Thiele and Günther first reported a 6-step preparation in 1906.[6] 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.[7]

Reactions

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

2 C6Cl2(CN)2O2 + C10H12 → 2 C6Cl2(CN)2(OH)2 + C10H8

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

Dehydrogenation

400px

Aromatization

400px[8]

Oxidative coupling

400px
[9]

Safety

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.

References

  1. ↑ 2,3-Dichloro-5,6-dicyano-p-benzoquinone at Sigma-Aldrich
  2. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  3. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  4. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  5. ↑ Derek R. Buckle, Steven J. Collier, Mark D. McLaws "2,3-Dichloro-5,6-dicyano-1,4-benzoquinone" in E-EROS ENCYCLOPEDIA OF REAGENTS FOR ORGANIC SYNTHESIS, 2005. doi:10.1002/047084289X.rd114.pub2
  6. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  7. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  8. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  9. ↑ Lua error in package.lua at line 80: module 'strict' not found.

External links

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