1,5-Cyclooctadiene

Chemical Properties

1,5-Cyclooctadiene is the organic compound with the chemical formula C8H12.It is a colorless liquid with a strong odor. COD has a boiling point of 151°C and a vapor pressure of 6.8mm at 25°C.

Uses

1,5-Cyclooctadiene is generally abbreviated COD, this diene is a useful precursor to other organic compounds and serves as a ligand in organometallic chemistry. 1,5-Cyclooctadiene can be prepared by dimerization of butadiene in the presence of a nickel catalyst, a coproduct being vinylcyclohexene. It is also a chemical intermediate in the production of Nylon.

Chemical Properties

colourless liquid

Uses

Cycloocta-1,5-diene is produced from petroleum distillation fractions and is used as an intermediate in the plastics industry, as a synthetic lubricant, and in numerous other applications.

Synthesis Reference(s)

Tetrahedron Letters, 24, p. 3913, 1983 DOI: 10.1016/S0040-4039(00)94312-0

Synthesis

Fifty mL of THF was added to a 150 mL flask containing (2.53 mmol) saturated methylsilanes.Ni(COD)2 (0.64 mmol) was dissolved in 25 mL of THF in a separate flask. The flasks were cooled to 0C. The flasks were combined through a cannula. The reaction mixture was heated to room temperature. The mixture was stirred for 1 hour. The flask was drained with a pump. The flask was heated to 70C under vacuum to remove the cyclooctadiene and unreacted methicone. Redissolve the residue in toluene. The residue was filtered. Cooling the saturated toluene solution gave the title compound 1,5-cyclooctadiene by evaporation.

Carcinogenicity

None of the components present in this material at concentrations of 0.1% are listed by IARC, NTP, or OSHA as a carcinogen.

Purification Methods

Purify it by GLC. It has been purified via the AgNO3 salt. This is prepared by shaking with a solution of 50% aqueous AgNO3 w/w several times (e.g. 3 x 50mLand4x50mL) at 70ofor ca 20minutes to get a good separation of layers. The upper layers are combined and further extracted with AgNO3 at 40o (2 x 20 mL). The upper layer (19 mL) of original hydrocarbon mixture gives colourless needles of the AgNO3 complex on cooling. The adduct is recrystallised from MeOH (and cooling to 0o). The hydrocarbon is recovered by steam distilling the salt. The distillate is extracted with Et2O, dried (MgSO4), filtered, evaporated and distilled. [Jones J Chem Soc 312 1954,[Beilstein 5 H 116, 5 IV 403.]