What affects octane number?
The octane number is affected by two main features of alkane molecules. Higher octane numbers occur with: • more branching: 2-methylbutane is less likely to autoignite than pentane. • shorter chains: pentane is less likely to autoignite than heptane Isomerisation Isomerisation is a process by which straight chain alkanes are converted to branch chain alkanes that can be blended in petrol to improve its octane rating.
