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a liquid alkane hydrocarbon found in petroleum and existing in 18 isomeric forms, esp the isomer n-octane. Formula: C8H18
Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.



n-octane, a saturated hydrocarbon, C6H18; a colorless liquid with a characteristic odor. Melting point, –56.8°C; boiling point, 125.67°C; density, 0.7025 g/cm3 at 20°C; octane number, 17–19. Along with isooctane and other isomers, octane is found in petroleum and straight-run gasoline (up to 10 percent); large quantities of octane are present in synthetic gasoline prepared from CO and H2.

Octane is extracted commercially by rectification, then refined with urea or by means of molecular sieves. At 500°C and a pressure of 1–2 meganewtons per sq m, or 10–20 kilograms-force per sq cm, octane converts into a mixture of aromatic hydrocarbons (o-xylene and ethylbenzene) when passed over an aluminum-molybdenum or aluminum-chromium catalyst in the presence of hydrogen. This dehydrocyclization reaction is one of the main processes used in catalytic reforming.

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.