Cyclooctane

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Cyclooctane
Regular octagon.svg
Names
Preferred IUPAC name
Cyclooctane
Other names
Cyclo-octane
Identifiers
3D model (JSmol)
ChEMBL
ChemSpider
ECHA InfoCard 100.005.484 OOjs UI icon edit-ltr-progressive.svg
PubChem CID
UNII
  • InChI=1S/C8H16/c1-2-4-6-8-7-5-3-1/h1-8H2 Yes check.svgY
    Key: WJTCGQSWYFHTAC-UHFFFAOYSA-N Yes check.svgY
  • InChI=1/C8H16/c1-2-4-6-8-7-5-3-1/h1-8H2
    Key: WJTCGQSWYFHTAC-UHFFFAOYAO
  • C1CCCCCCC1
Properties
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]
7.90 mg/L
−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).
Yes check.svgY  verify  (what is  Yes check.svgYX mark.svgN ?)

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.

Contents

Cyclooctane has a camphoraceous odor. [3]

Conformations

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.

Cyclooctane boat-chair conformation.svg Cyclooctane-boat-chair-3D-balls.png Cyclooctane crown conformation.svg Cyclooctane-crown-3D-balls.png
Boat-chair [7] Crown [7]
Cyclooctane tub conformation.svg Cyclooctane boat-boat conformation.svg Cyclooctane twist boat-chair conformation.svg Cyclooctane twist chair-chair conformation.svg
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 CyclooctaneAmination.png
Amination of cyclooctane by nitrobenzene

References

  1. 1 2 3 ECHA REACH
  2. ↑ Mackay, Donald (2006). Handbook of Physical-chemical Properties and Environmental Fate for Organic Chemicals. CRC Press. p. 258. ISBN   978-1-56670-687-2.
  3. ↑ Sell, C. S. (2006). "On the Unpredictability of Odor". Angew. Chem. Int. Ed. 45 (38): 6254–6261. doi:10.1002/anie.200600782. PMID   16983730.
  4. ↑ Hendrickson, James B. (1967). "Molecular Geometry V. Evaluation of Functions and Conformations of Medium Rings". Journal of the American Chemical Society . 89 (26): 7036–7043. doi:10.1021/ja01002a036.
  5. ↑ Dorofeeva, O. V.; Mastryukov, V. S.; Allinger, N. L.; Almenningen, A. (1985). "The molecular structure and conformation of cyclooctane as determined by electron diffraction and molecular mechanics calculations". The Journal of Physical Chemistry. 89 (2): 252–257. doi:10.1021/j100248a015.
  6. ↑ IUPAC, Compendium of Chemical Terminology , 2nd ed. (the "Gold Book") (1997). Online corrected version: (2006–) "crown conformation". doi:10.1351/goldbook.C01422
  7. 1 2 3 4 5 Pakes, P. W.; Rounds, T. C.; Strauss, H. L. (1981). "Conformations of cyclooctane and some related oxocanes". The Journal of Physical Chemistry. 85 (17): 2469–2475. doi:10.1021/j150617a013. ISSN   0022-3654.
  8. ↑ Moss, G. P. (1996). "Basic terminology of stereochemistry (IUPAC Recommendations 1996)". Pure and Applied Chemistry. 68 (12): 2193–2222. doi: 10.1351/pac199668122193 . ISSN   0033-4545. S2CID   98272391.
  9. ↑ Thomas Schiffer, Georg Oenbrink, “Cyclododecatriene, Cyclooctadiene, and 4-Vinylcyclohexene” in Ullmann’s Encyclopedia of Industrial Chemistry, 2005, Wiley-VCH, Weinheim. doi:10.1002/14356007.a08_205.
  10. ↑ Deng, Guojun; Wenwen Chen; Chao-Jun Li (February 2009). "An Unusual Peroxide-Mediated Amination of Cycloalkanes with Nitroarenes". Advanced Synthesis & Catalysis. 351 (3): 353–356. doi:10.1002/adsc.200800689.
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