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Skeletal formula with all implicit hydrogen shown, skeletal formula; stereo, skeletal formula with all explicit hydrogens added, all of 1,4-cyclohexadiene
1,4-Cyclohexadiene molecule 1,4-Cyclohexadiene molecule
Abbreviations 1,4-CHDN
CAS number 628-41-1 YesY
PubChem 12343
ChemSpider 11838 YesY
EC number 211-043-1
UN number 3295
MeSH 1,4-cyclohexadiene
ChEBI CHEBI:37611 YesY
Beilstein Reference 1900733
Gmelin Reference 1656
Jmol-3D images Image 1
Molecular formula C6H8
Molar mass 80.13 g mol−1
Appearance Colorless liquid
Density 0.847 g cm−3
Melting point −50 °C; −58 °F; 223 K
Boiling point 82 °C; 179 °F; 355 K
Refractive index (nD) 1.472
heat capacity
142.2 J K-1 mol-1
Std molar
189.37 J K-1 mol-1
Std enthalpy of
63.0-69.2 kJ mol-1
Std enthalpy of
-3573.5--3567.5 kJ mol-1
GHS pictograms The flame pictogram in the Globally Harmonized System of Classification and Labelling of Chemicals (GHS) The health hazard pictogram in the Globally Harmonized System of Classification and Labelling of Chemicals (GHS)
GHS signal word DANGER
GHS hazard statements H225, H340, H350, H373
GHS precautionary statements P201, P210, P308+313
EU classification Highly Flammable F Toxic T
R-phrases R45 R46 R11 R48/20/21/22
S-phrases S53 S45
NFPA 704
Flammability code 3: Liquids and solids that can be ignited under almost all ambient temperature conditions. Flash point between 23 and 38 °C (73 and 100 °F). E.g., gasoline) Health code 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g., chloroform Reactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g., liquid nitrogen Special hazards (white): no codeNFPA 704 four-colored diamond
Flash point −7 °C (19 °F; 266 K)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
 YesY (verify) (what is: YesY/N?)
Infobox references

1,4-Cyclohexadiene is an organic compound with the formula C6H8. It is a colourless, flammable liquid that is of academic interest as a prototype of a large class of related compounds called terpenoids, an examples being γ-terpinene. An isomer exists of this compound, 1,3-cyclohexadiene.

Synthesis and reactions[edit]

In the laboratory, substituted 1,4-cyclohexadienes are synthesized by Birch reduction of related aromatic compounds using an alkali metal and a proton donor such as ammonia. In this way, over reduction to the fully saturated ring is avoided.

1,4-Cyclohexadiene and its derivatives are easily aromatized, the driving force being the formation of an aromatic ring. The conversion to an aromatic system may be performed in the laboratory using an alkene such as styrene, along with a hydrogen transfer agent such as palladium metal supported on charcoal.


  1. ^ "1,4-cyclohexadiene - Compound Summary". PubChem Compound. USA: National Center for Biotechnology Information. 27 March 2005. Identification and Related Records. Retrieved 12 October 2011. 

External links[edit]