Octane
| General
|
| Molecular formula
| C8H18
|
| CAS number
| 111-65-9
|
| EC number
| 203-892-1
|
| Annex I Index number
| 601-009-00-8
|
| Physical characteristics
|
| Appearance
| Colourless liquid
|
| Melting point
| -57° Celsius
|
| Boiling point
| 126° Celsius
|
| Vapour density
| -
|
| Vapour pressure
| 11 mm Hg at 20° Celsius
|
| Specific gravity
| 0.703
|
| Flash point
| 15° Celsius (closed cup)
|
| Explosion limits
| 0.96 - 6.5 %
|
| Autoignition temperature
| 220° Celsius
|
| Critical temperature
| 295.7° Celsius
|
Octane is an alkane hydrocarbon with the chemical formula CH3(CH2)6CH3. It has many isomers.
One of the isomers, the iso-octane 2,2,4-trimethylpentane , is of major importance, as it has been selected as the 100 point on the octane rating scale, with n-heptane as the zero point. Octane ratings are ratings used to represent the anti-knock performance of petrol, given as the percentage of 2,2,4-trimethylpentane in an 2,2,4-trimethylpentane / n-heptane mixture that would have the same performance. It is an important constituent of gasoline.
See also
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