Gasoline (gas), petroleum spirit (petrol) or petrogasoline is a petroleum-derived liquid mixture consisting mostly of aliphatic hydrocarbons, enhanced with iso-octane or the aromatic hydrocarbons toluene and benzene to increase its octane rating, and is primarily used as fuel in internal combustion engines.

Except for Canada, most current or former Commonwealth countries use the word "petrol", abbreviated from petroleum spirit. In North America, the word "gasoline" is commonly used, where it is often shortened in colloquial usage to "gas." It is not a genuinely gaseous fuel like liquefied petroleum gas, which is stored under pressure as a liquid but allowed to return to a gaseous state before combustion.

Mogas, short for motor gasoline, distinguishes automobile fuel from aviation gasoline, or avgas. In British English "gasoline" can refer to a different petroleum derivative historically used in lamps, but this is now uncommon.

History

Gasoline is a mixture of hydrocarbons, although some may contain significant quantities of ethanol and some may contain small quantities of additives such as methyl tert-butyl ether as anti-knock agents to increase the octane rating or as an oxygenate to reduce emissions. The hydrocarbons consist of a mixture of n-paraffins, naphthenes, olefins and aromatics. Naphthenes, olefins and aromatics increase the octane rating of the gasoline whereas the n-paraffins have the opposite effect.

Early uses

In the USA, gasoline was also sold as a cleaning fluid to remove grease stains from clothing. Before dedicated filling stations were established, early motorists bought gasoline in cans to fill their tanks.

The name gasoline is similar to that of other petroleum products of the day, most notably petroleum jelly, a highly purified heavy distillate, which was branded Vaseline. The trademark Gasoline was never registered, and thus became generic.

Gasoline was also used in kitchen ranges and for lighting, and is still available in a highly purified form, known as camping fuel or white gas, for use in lanterns and portable stoves.

During the Franco-Prussian War (1870–1871), pétrole was stockpiled in Paris for use against a possible German-Prussian attack on the city. Later in 1871, during the revolutionary Paris Commune, rumours spread around the city of pétroleuses, women using bottles of petrol to commit arson against city buildings.

Etymology

The word "gasolene" was coined in 1865 from the word gas and the chemical suffix -ine/-ene. The modern spelling was first used in 1871. The shortened form "gas" for gasoline was first recorded in American English in 1905 Online Etymology Dictionary and is often confused with the older words gas and gases that have been used since the early 1600s. Gasoline originally referred to any liquid used as the fuel for a gasoline-powered engine, other than diesel fuel or liquefied gas; methanol racing fuel would have been classed as a type of gasoline.