Gasoline
Leaded gasoline hit the U.S. market in Dayton, OH, 1923, when Thomas Midgley, Jr., of General Motors Research labs added tetraethyllead to gasoline.
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In a nutshell, gasoline is a mixture of C4 to C12 hydrocarbons specially blended with a few additives to meet the performance needs of automobile engines.
That doesn’t sound too complicated, but in actuality gasoline is quite complex, consisting of several hundred compounds. The composition of gasoline can vary widely depending on the blending specifications required for different regions based on climate and environmental regulations. The trick, as one source puts it, is to formulate a gasoline that “does not cause engines to knock apart, does not cause vapor lock in summer but is easy to start in winter, does not form gums and deposits, burns cleanly without forming soot or residues, and does not dissolve or poison the car catalyst or owner.”
The raw material for gasoline, at least for now, is crude oil, which can contain as many as 100,000 compounds ranging from methane to those having 85 carbon atoms. In a refinery, some of the major crude oil fractions obtained upon initial distillation are “light ends,” such as propane and butane; “straight run” gasoline, which is mostly C5 and C6 alkanes, the higher boiling part of which is sometimes called naphtha; kerosene; diesel fuel; heating oil; and lubricating oils. There also are some nondistillable residues.
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Excerpted with permission, Chemical & Engineering News
Copyright © 2005 American Chemical Society