Cyclohexa-1,4-diene

Cyclohexa-1,4-diene
Names
	Systematic IUPAC name Cyclohexa-1,4-diene
	Other names 1,4-Cyclohexadiene; 1,4-Dihydrobenzene
Identifiers
CAS Number	628-41-1 ;
3D model (JSmol)	Interactive image;
Abbreviations	1,4-CHDN
Beilstein Reference	1900733
ChEBI	CHEBI:37611 ;
ChemSpider	11838 ;
ECHA InfoCard	100.010.040
EC Number	211-043-1;
Gmelin Reference	1656
MeSH	1,4-cyclohexadiene
PubChem CID	12343;
UNII	0F8Z5909QZ ;
UN number	3295
CompTox Dashboard (EPA)	DTXSID0060854 ;
	InChI InChI=1S/C6H8/c1-2-4-6-5-3-1/h1-2,5-6H,3-4H2 Key: UVJHQYIOXKWHFD-UHFFFAOYSA-N ; InChI=1/C6H8/c1-2-4-6-5-3-1/h1-2,5-6H,3-4H2 Key: UVJHQYIOXKWHFD-UHFFFAOYAM;
	SMILES C1C=CCC=C1;
Properties
Chemical formula	C6H8
Molar mass	80.130 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
Magnetic susceptibility (χ)	-48.7·10−6 cm3/mol
Refractive index (nD)	1.472
Thermochemistry
Heat capacity (C)	142.2 J K−1 mol−1
Std molar; entropy (So298)	189.37 J K−1 mol−1
Std enthalpy of; formation (ΔfH⦵298)	63.0-69.2 kJ mol−1
Std enthalpy of; combustion (ΔcH⦵298)	-3573.5--3567.5 kJ mol−1
Hazards
GHS pictograms
GHS Signal word	Danger
GHS hazard statements	H225, H340, H350, H373
GHS precautionary statements	P201, P210, P308+313
NFPA 704 (fire diamond)	3 2 0
Flash point	−7 °C (19 °F; 266 K)
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

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

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 used to trigger other reactions, such as the Bergman cyclization.^[2]

References

^ "1,4-cyclohexadiene - Compound Summary". PubChem Compound. USA: National Center for Biotechnology Information. 27 March 2005. Identification and Related Records. Retrieved 12 October 2011.
^ John C. Walton, Fernando Portela-Cubillo "1,4-Cyclohexadiene" Encyclopedia of Reagents for Organic Synthesis 2007 John Wiley & Sons. doi:10.1002/047084289X.rn00806

External links

The photochemistry of 1,4-cyclohexadiene in solution and in the gas phase
NIST Chemistry WebBook Reaction thermochemistry data

[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.

[2] John C. Walton, Fernando Portela-Cubillo "1,4-Cyclohexadiene" Encyclopedia of Reagents for Organic Synthesis 2007 John Wiley & Sons. doi:10.1002/047084289X.rn00806

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