Gasoline is a complex mixture of hundreds of different hydrocarbons. Most are relatively small, with 4 to 12 carbon atoms per molecule. The primary components include:
Modern gasoline is rarely just "straight-run" from a distillation tower. To meet high demand and performance standards, refineries use several chemical processes:
The initial separation of crude oil into different "fractions" based on boiling points.
Breaking down large, heavy hydrocarbon molecules into the smaller ones that make up gasoline. This is often done using heat (thermal cracking) or catalytic cracking to improve yields.
), and particulate matter, contributing to global warming and smog.
This measures a fuel's resistance to "knocking" or "pinging" during combustion. Higher octane numbers indicate the fuel can withstand more compression before detonating.
Straight or branched chain hydrocarbons.