Cyclohexa-1,4-diene

Summary

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.

Cyclohexa-1,4-diene
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
Names
Preferred IUPAC name
Cyclohexa-1,4-diene[1]
Other names
1,4-Cyclohexadiene[citation needed]
1,4-Dihydrobenzene[citation needed]
Identifiers
  • 628-41-1 checkY
3D model (JSmol)
  • Interactive image
Abbreviations 1,4-CHDN
1900733
ChEBI
  • CHEBI:37611 checkY
ChemSpider
  • 11838 checkY
ECHA InfoCard 100.010.040 Edit this at Wikidata
EC Number
  • 211-043-1
1656
MeSH 1,4-cyclohexadiene
  • 12343
UNII
  • 0F8Z5909QZ checkY
UN number 3295
  • DTXSID0060854 Edit this at Wikidata
  • InChI=1S/C6H8/c1-2-4-6-5-3-1/h1-2,5-6H,3-4H2 checkY
    Key: UVJHQYIOXKWHFD-UHFFFAOYSA-N checkY
  • C1C=CCC=C1
Properties
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
-48.7·10−6 cm3/mol
1.472
Thermochemistry
142.2 J K−1 mol−1
189.37 J K−1 mol−1
63.0-69.2 kJ mol−1
-3573.5--3567.5 kJ mol−1
Hazards
GHS labelling:
GHS02: Flammable GHS08: Health hazard
Danger
H225, H340, H350, H373
P201, P210, P308+P313
NFPA 704 (fire diamond)
2
3
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

Synthesis and reactionsEdit

In the laboratory, substituted 1,4-cyclohexadienes are synthesized by Birch reduction of related aromatic compounds using an alkali metal dissolved in liquid ammonia and a proton donor such as an alcohol. 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]

ReferencesEdit

  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

External linksEdit

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