Toluene, formerly known as toluol, is a colourless, water-insoluble liquid with the smell associated with paint thinners. It is a mono-substituted benzene derivative, consisting of a CH₃ group attached to a phenyl group.
Toluene is used as a solvent and to make aviation gasoline, spray and wall paints, paint thinner, medicine, dyes, explosives, detergents, fingernail polish, spot removers, lacquers, adhesives, rubber, and antifreeze. It is also used in some printing and leather tanning processes.
The largest industrial use of toluene is in the production of benzene, a chemical used to make plastics and synthetic fibers. Toluene is also used to boost the octane of gasoline. Toluene is a volatile organic compound (VOC).