Octane

Octane has many structural isomers that differ by the location of branching in the carbon chain.

One of these isomers, 2,2,4-trimethylpentane (commonly called iso-octane), is used as one of the standard values in the octane rating scale.

Under standard temperature and pressure, octane is an odorless, colorless liquid.

Like other short-chained alkanes with a low molecular weight, it is volatile, flammable, and toxic.

[6] A common route to such fractions is the alkylation reaction between iso-butane and 1-butene, which forms iso-octane.

Skeletal formula of octane
Skeletal formula of octane with all implicit carbons shown, and all explicit hydrogens added
Ball-and-stick model of octane
Space-filling model of octane
NFPA 704 four-colored diamond Health 1: Exposure would cause irritation but only minor residual injury. E.g. turpentine Flammability 3: Liquids and solids that can be ignited under almost all ambient temperature conditions. Flash point between 23 and 38 °C (73 and 100 °F). E.g. gasoline Instability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogen Special hazards (white): no code
(3 S ,4 S )-3,4-Dimethylhexane (top left) and (3 R ,4 R )-3,4-Dimethylhexane (top right) are non-superimposable mirror images, so they are chiral enantiomers . ( meso )-3,4-Dimethylhexane (bottom) has a superimposable mirror image, so it is an achiral meso compound .
N-octane is the octane isomer that has the longest carbon skeleton. Unlike its constitutional isomers, it has a very low knock resistance.
The octane isomer, iso-octane , is used as one of the standards for octane ratings. It has a rating of 100 by definition.
The octane isomer 2,3,3-Trimethylpentane has an octane rating exceeding 100.