1,4-Cyclohexadiene

1,4-Cyclohexadiene

Names
Systematic IUPAC name Cyclohexa-1,4-diene[1]
Other names 1,4-Cyclohexadiene 1,4-Dihydrobenzene
Identifiers
CAS Number	628-41-1 Y
3D model (Jmol)	Interactive image
Abbreviations	1,4-CHDN
Beilstein Reference	1900733
ChEBI	CHEBI:37611 Y
ChemSpider	11838 Y
ECHA InfoCard	100.010.040
EC Number	211-043-1
Gmelin Reference	1656
MeSH	1,4-cyclohexadiene
PubChem	12343
UN number	3295
InChI InChI=1S/C6H8/c1-2-4-6-5-3-1/h1-2,5-6H,3-4H2 Y Key: UVJHQYIOXKWHFD-UHFFFAOYSA-N Y 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	80.13 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
Thermochemistry
Specific 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 (ΔfHo298)	63.0-69.2 kJ mol−1
Std enthalpy of combustion (ΔcHo298)	-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
EU classification (DSD)	F T
R-phrases	R45 R46 R11 R48/20/21/22
S-phrases	S53 S45
NFPA 704	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).
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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

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.

References

External links

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