Cyclooctane

Cyclooctane is a cycloalkane with the molecular formula (CH₂)₈.^[2] It is a simple colourless hydrocarbon, but it is often a reference compound for saturated eight-membered ring compounds in general.

Cyclooctane

Names
Preferred IUPAC name Cyclooctane
Other names Cyclo-octane
Identifiers
CAS Number	292-64-8 Y
3D model (JSmol)	Interactive image
ChEMBL	ChEMBL452651 Y
ChemSpider	8909 Y
ECHA InfoCard	100.005.484
PubChem CID	9266
UNII	KKZ3KBS654 Y
CompTox Dashboard (EPA)	DTXSID9075377
InChI InChI=1S/C8H16/c1-2-4-6-8-7-5-3-1/h1-8H2 Y Key: WJTCGQSWYFHTAC-UHFFFAOYSA-N Y InChI=1/C8H16/c1-2-4-6-8-7-5-3-1/h1-8H2 Key: WJTCGQSWYFHTAC-UHFFFAOYAO
SMILES C1CCCCCCC1
Properties
Chemical formula	C8H16
Molar mass	112.216 g·mol−1
Density	0.840 g/cm3[1]
Melting point	14.5 °C (58.1 °F; 287.6 K)[1]
Boiling point	151.2 °C (304.2 °F; 424.3 K)[1]
Solubility in water	7.90 mg/L
Magnetic susceptibility (χ)	−91.4·10−6 cm3/mol
Related compounds
Related cycloalkanes	Cycloheptane
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Y verify (what is YN ?) Infobox references

Cyclooctane has a camphoraceous odor.^[3]

Conformations

Further information: Macrocyclic stereocontrol § Cyclooctane

The conformation of cyclooctane has been studied extensively using computational methods. Hendrickson noted that "cyclooctane is unquestionably the conformationally most complex cycloalkane owing to the existence of many conformers of comparable energy". The boat-chair conformation (below) is the most stable form.^[4] Allinger and co-workers confirmed this.^[5] The crown conformation (below)^[6] is slightly less stable. Among the many compounds exhibiting the crown conformation (structure II) is S₈, elemental sulfur.

Boat-chair[7]		Crown[7]
Tub[8]	Boat-boat[7]	Twist boat-chair[7]	Twist chair-chair[7]

Synthesis and reactions

The main route to cyclooctane derivatives involves the dimerization of butadiene, catalysed by nickel(0) complexes such as nickel bis(cyclooctadiene).^[9] This process affords, among other products, 1,5-cyclooctadiene (COD), which can be hydrogenated. COD is widely used for the preparation of precatalysts for homogeneous catalysis. The activation of these catalysts under H₂, produces cyclooctane, which is usually discarded or burnt:

C₈H₁₂ + 2 H₂ → C₈H₁₆

Cyclooctane participates in no reactions except those typical of other saturated hydrocarbons, combustion and free radical halogenation. Work in 2009 on alkane functionalisation, using peroxides such as dicumyl peroxide, has opened up the chemistry to some extent, allowing for example the introduction of a phenylamino group.^[10]

Amination of cyclooctane by nitrobenzene