Octane

CAS 111-65-9

n-Octane is a chemical substance, while an octane number is a fuel-performance rating. CAS 111-65-9 identifies the unbranched eight-carbon alkane, not the branched isooctane reference. Its defined structure makes it useful in combustion research and kinetic-model comparisons. Studies have examined normal-alkane reaction networks and compared n-octane with branched 2-methylheptane in a diffusion flame. Such comparisons help distinguish carbon count from carbon arrangement. The overall combustion equation and a detailed reaction mechanism answer different questions: atom balance versus pathways and rates. Its story shows why exact identity, experimental conditions, and model validation belong together. A familiar fuel label does not replace the evidence needed to explain how a particular molecule reacts under the actual conditions being investigated in a laboratory system.