ottano

Ottano is the Italian term for octane, a hydrocarbon with the formula C8H18 and a central component of gasoline. There are 18 structural isomers of octane, including n-octane (straight-chain) and iso-octane (2,2,4-trimethylpentane).

In fuel technology, octane refers to a fuel’s resistance to knocking in spark-ignition engines; higher octane allows higher compression without premature ignition. Octane ratings are commonly expressed as Research Octane Number (RON) and Motor Octane Number (MON). The average of the two, (RON + MON) / 2, is used in many markets as the posted anti-knock index (AKI). Iso-octane is a reference compound with an octane rating of 100 on the RON scale.

Octane content in fuels is increased by refining steps such as catalytic reforming, isomerization, and alkylation, and by blending with high-octane components like isooctane and aromatics. Branched isomers typically have higher octane numbers than straight-chain alkanes, so these processes boost the fuel’s octane rating while aiming to maintain energy content and emission targets.

Outside of technical contexts, ottano appears primarily in Italian-language chemistry and fuel literature. In English-language sources, the same concept is usually referred to as octane or octane rating.