Gasoline
The word gasoline first appeared in English dictionaries during the late 19th century. It combines gas with chemical suffixes like -ole and -ine to describe a volatile liquid fuel. Petrol derives from Medieval Latin petroleum, which means rock oil. Interest in such fuels grew alongside the invention of internal combustion engines suitable for transportation applications. German engineers developed Otto engines during the last quarter of the 1800s. These early machines required a relatively volatile hydrocarbon obtained from coal gas. The boiling point of this fuel sat near that of n-octane. Such volatility made it well suited for early carburettors or evaporators. A spray nozzle carburettor later enabled the use of less volatile fuels. Engineers attempted further improvements at higher compression ratios. Early attempts were blocked by premature explosion of fuel known as knocking. In 1891, the Shukhov cracking process became the world's first commercial method to break down heavier hydrocarbons. This technique increased the percentage of lighter products compared to simple distillation.
Commercial gasoline is produced inside oil refineries around the globe. Roughly 45 percent of gasoline comes from each barrel of crude oil processed. Material separated via distillation called virgin or straight-run gasoline does not meet modern engine specifications. Straight run naphtha has a low octane rating requiring organometallic additives prior to their phaseout. The bulk of typical gasoline consists of a homogeneous mixture of hydrocarbons with four to twelve carbon atoms per molecule. It contains paraffins, olefins, naphthenes, and aromatics in varying proportions. Some important streams include reformate produced from straight run gasoline in a catalytic reformer. Reformate has a high octane rating with high aromatic content. Catalytic cracked gasoline has moderate octane ratings and high olefin content. Hydrocrackate possesses medium to low octane ratings and moderate aromatic levels. Alkylate contains no aromatics or olefins and has a high Motor Octane Number. Isomerate results from isomerizing low-octane straight-run gasoline into iso-paraffins. Butane usually blends into the gasoline pool though its quantity remains limited by Reid vapor pressure specifications. Oxygenates like ethanol appear frequently in the United States while MTBE and ETBE dominate elsewhere.
The ability of gasoline to resist premature ignition measures its octane rating. This number determines how well fuel performs inside reciprocating engines without causing knocking. Octane rating compares 2,2,4-trimethylpentane against n-heptane mixtures. In Finland, Sweden, and Norway, 95 RON serves as the standard for regular unleaded gasoline. The United Kingdom sells over 95 percent of gasoline at 95 RON labeled Unleaded or Premium Unleaded. Super Unleaded reaches 97 or 98 RON while racing fuels hit 102 RON. American markets vary between 85 and 87 AKI for regular grades up to 94 AKI for premium. South Africa's largest city Johannesburg sits on the Highveld at 1,753 meters above sea level. Automobile Association of South Africa recommends 95-octane gasoline at low altitude but 93-octane for use in Johannesburg. Higher altitude reduces air pressure and lowers the need for high octane fuel. Military interest drove octane ratings importance during the late 1920s and 1940s. A higher rating allows a higher compression ratio or supercharger boost translating to higher power output. Rolls-Royce Merlin aero engines produced 1,000 horsepower using 100 RON fuel from a modest displacement in 1943. Operation Overlord saw RAF and USAAF operations using 150 RON fuel obtained by adding 2.5 percent aniline to 100-octane avgas.
Tetraethyl lead was widely adopted as an additive for gasoline in the 1920s to address engine knocking. Growing awareness of environmental and health damage caused lead compounds to face government mandates. The U.S. Environmental Protection Agency issued regulations to reduce lead content over annual phases starting in 1973. Court appeals delayed implementation until 1976. By 1995, leaded fuel accounted for only 0.6 percent of total gasoline sales. The U.S. Clean Air Act banned sale of leaded fuel for on-road vehicles from the 1st of January 1996. European countries began replacing lead-containing additives by the end of the 1980s. Leaded gasoline was banned within the entire European Union by the end of the 1990s except for Avgas 100LL. Algeria depleted its last reserves in August 2021 making it the final country to stop production. UN Secretary-General António Guterres called the eradication an international success story. Lead replacement petrol contained potassium compounds or methylcyclopentadienyl manganese tricarbonyl instead of tetraethyllead. MMT remains used in Canada and the U.S. to boost octane rating though restricted by regulations. Ethanol blends appear frequently with E10 containing 10 percent ethanol mixed with gasoline. Brazil requires 27.5 percent ethanol added to automobile gasoline composition. India mandated blending of E20 in July 2025 despite facing backlash.
Gasoline prices fluctuate significantly across different regions and time periods. From 1998 to 2004, prices ranged between 1.00 and 3.00 dollars per gallon in the United States. Average gasoline price reached a high of 4.11 dollars in mid-2008 before receding to approximately 2.36 dollars by September 2009. California prices remain higher due to unique government mandates on formulas and taxes. The federal tax was 18.4 cents for gasoline and 24.4 cents for diesel excluding red diesel. Europe imposes substantially higher taxes on fuels compared to the U.S. resulting in typically higher prices. About nine percent of all gasoline sold in the U.S. in May 2009 was premium grade according to Energy Information Administration data. Worldwide seven liters of gasoline burn for every 100 kilometers driven by cars and vans. Oil products including gasoline were responsible for about 32 percent of carbon dioxide emissions worldwide in 2021. The International Energy Agency stated road fuels should be taxed at rates reflecting impact on health and climate. Gasoline production varies by country with the U.S., China, Japan, Russia, India, Canada, Brazil, Germany, Saudi Arabia, and Mexico leading global output. The cost imposed on society and planet estimates $3.80 per gallon beyond pump price.
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Common questions
When did the word gasoline first appear in English dictionaries?
The word gasoline first appeared in English dictionaries during the late 19th century. It combines gas with chemical suffixes like -ole and -ine to describe a volatile liquid fuel.
What percentage of crude oil becomes commercial gasoline in refineries?
Roughly 45 percent of gasoline comes from each barrel of crude oil processed inside oil refineries around the globe. Material separated via distillation called virgin or straight-run gasoline does not meet modern engine specifications.
Which country was the final nation to stop producing leaded gasoline in August 2021?
Algeria depleted its last reserves in August 2021 making it the final country to stop production. The U.S. Clean Air Act banned sale of leaded fuel for on-road vehicles from the 1st of January 1996.
How much ethanol is required in Brazil automobile gasoline composition?
Brazil requires 27.5 percent ethanol added to automobile gasoline composition. Ethanol blends appear frequently with E10 containing 10 percent ethanol mixed with gasoline.
When did the United States Environmental Protection Agency issue regulations to reduce lead content starting in 1973?
The U.S. Environmental Protection Agency issued regulations to reduce lead content over annual phases starting in 1973. Court appeals delayed implementation until 1976 and by 1995, leaded fuel accounted for only 0.6 percent of total gasoline sales.