Definition
An aromatic hydrocarbon liquid (chemical formula C6H5CH3) used as a solvent and as a high-octane blending component in aviation gasoline. It is clear, flammable, and has a strong sweet odor.
Plain English
A clear, flammable liquid chemical used as a solvent for cleaning and as an ingredient added to aviation fuel to help it burn smoothly without knocking.
Context Anchor
Seen in fuel chemistry, aviation gasoline discussions, maintenance references, and safety information for fuels or solvents.
Derivation
Named after tolu balsam, a resin from the South American tolu tree, from which toluene was first isolated in the 1830s. The '-ene' ending indicates it is a hydrocarbon containing a ring of carbon atoms.
Why Pilots Care
Toluene is one of the components that gives aviation gasoline its high octane rating, which allows engines to run at higher power settings without detonation. It is also a strong solvent, so spilled avgas can damage paint, plastics, and rubber seals.
Intuition Check
Do not treat toluene as just another name for gasoline. It is one specific chemical that may be present in or used with fuel.
Example Sentence 1
Toluene is added to aviation gasoline to raise its octane rating and prevent detonation in high-compression engines.
Example Sentence 2
Some experimental fuels include toluene to raise the octane level without lead.