Cyclooctane is a cycloalkane with the

molecular formula In chemistry, a chemical formula is a way of presenting information about the chemical proportions of atoms that constitute a particular chemical compound or molecule, using chemical element symbols, numbers, and sometimes also other symbols, ...

(CH₂)₈. It is a simple colourless

hydrocarbon In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons are examples of group 14 hydrides. Hydrocarbons are generally colourless and hydrophobic, and their odors are usually weak or ...

, but it is often a reference compound for saturated eight-membered ring compounds in general. Cyclooctane has a camphoraceous odor.

Conformations

The conformation of cyclooctane has been studied extensively using

computational Computation is any type of arithmetic or non-arithmetic calculation that follows a well-defined model (e.g., an algorithm). Mechanical or electronic devices (or, historically, people) that perform computations are known as ''computers''. An espe ...

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. This conformation was confirmed by Allinger and co-workers. The crown conformation (below) is slightly less stable. Among the many compounds exhibiting the crown conformation (structure II) is S₈, elemental sulfur. :

Synthesis and reactions

The main route to cyclooctane derivatives involves the dimerization of

butadiene 1,3-Butadiene () is the organic compound with the formula (CH2=CH)2. It is a colorless gas that is easily condensed to a liquid. It is important industrially as a precursor to synthetic rubber. The molecule can be viewed as the union of two vi ...

, catalysed by nickel(0) complexes such as

nickel bis(cyclooctadiene) Bis(cyclooctadiene)nickel(0) is the organonickel compound with the formula Ni(C8H12)2, also written Ni(cod)2. It is a diamagnetic coordination complex featuring tetrahedral nickel(0) bound to the alkene groups in two 1,5-cyclooctadiene ligands. Thi ...

. 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 In chemistry, homogeneous catalysis is catalysis by a soluble catalyst in a solution. Homogeneous catalysis refers to reactions where the catalyst is in the same phase as the reactants, principally in solution. In contrast, heterogeneous catalysi ...

. 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 Combustion, or burning, is a high-temperature exothermic redox chemical reaction between a fuel (the reductant) and an oxidant, usually atmospheric oxygen, that produces oxidized, often gaseous products, in a mixture termed as smoke. Combus ...

and

free radical halogenation In organic chemistry, free-radical halogenation is a type of halogenation. This chemical reaction is typical of alkanes and alkyl-substituted aromatics under application of UV light. The reaction is used for the industrial synthesis of chloroform ( ...

. 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. : CyclooctaneAmination

References

{{Authority control Cycloalkanes Hydrocarbon solvents Eight-membered rings