Gasoline - C&EN - American Chemical Society
Most people don't give car fuel much thought, but it is quite a complex mixture of hydrocarbons
cen.acs.orgGasoline doesn’t have a single chemical formula because it’s a complex blend of many hydrocarbons, but typical descriptions place its main components in the C4–C12 range, with an overall composition that varies by crude source and refinery blending. A commonly cited “average” idea is that gasoline is dominated by lightweight alkanes, branched alkanes, cycloalkanes, and aromatics, making up roughly 15–40% alkanes, 10–25% alkenes, 10–25% cycloalkanes, and a substantial fraction of aromatics, with benzene kept very low due to regulatory limits. Because it’s a mixture, there is no universal chemical formula like a pure compound; instead chemists often describe it by typical molecular ranges or representative compounds such as C8H18 as a simplified stand-in for an average hydrocarbon in gasoline.[1][4][6][7]
Latest high-level takeaways you might care about:
- Gasoline is a blend of roughly 150 chemicals refined from crude oil, not a single substance, which is why you’ll see ranges rather than one formula.[5]
- Common frameworks describe the bulk as C4–C12 hydrocarbons, with a typical mix that varies by gasoline grade and region, and additives further modify properties like octane and volatility.[4][6]
- Regulatory trends emphasize reducing benzene content and controlling toxic components, while oxygenates and detergents are used to improve performance and reduce emissions in certain blends.[6][7]
If you want, I can tailor a quick visual or a concise table comparing typical hydrocarbon fractions in gasoline (e.g., alkanes, cycloalkanes, aromatics) and show approximate ranges for each category. I can also pull the most current regional blending practices (US vs EU vs Asia) and summarize any notable regulatory limits for benzene or other key components.