Isooctane

Isooctane, or 2,2,4-trimethylpentane, is an isomer of octane with the chemical formula C8H18. It is a highly branched saturated hydrocarbon that serves as the standard reference fuel for the octane rating scale. On the Research Octane Number (RON) scale, isooctane has a value of 100, making it the benchmark against which other fuels are evaluated for resistance to knocking in internal combustion engines.

Structure and properties: Isooctane features multiple methyl branches on a five-carbon backbone, which contributes to its high octane performance by reducing premature combustion. It is a colorless, flammable liquid with low water solubility and good miscibility with other hydrocarbons. Its boiling point is around 99 °C, typical of light petroleum distillates.

Production and use: In petroleum refining, isooctane is produced through processes such as catalytic reforming and isomerization of straight-chain alkanes, and it can also be formed via alkylation to yield high-octane components. It is widely used as a blending component in gasoline to raise octane ratings and improve anti-knock characteristics, allowing engines to operate efficiently at higher compression.

Safety and handling: Isooctane is a flammable liquid. It should be stored in a cool, well-ventilated area away from sources of ignition and oxidizers. Appropriate precautions include using containers designed for flammable liquids and employing standard personal protective equipment when handling large quantities.

See also: Octane rating, gasoline blending, branched alkanes.