Fractional Distillation: This involves the heating of crude oil, and separating the various mixtures in the basis of their boiling points.
The Octane Number of a fuel is a measure of the tendency of the fuel to resist knocking.
- Heptane = 0
- 2,2,4 Trimethylpentane = 100
- Shorter the alkane chain, higher the octane number.
- More branched the chain, higher the octane number.
- Cyclic compounds have higher octane numbers than straight chain compounds.
Increasing the Octane Number
- Isomerisation – Changing straight chain alkanes into their isomers.
- Catalytic Cracking is the breaking down of long-chain hydrocarbon molecules into short chain molecules for which there is greater demand.
- Adding oxegenates involves the adding of compounds containing oxygen in their molecules.