Hexane

OVERVIEW

Hexane (HEX-ane) is a colorless flammable liquid with a faint petroleum-like odor. Chemically it is classified as a saturated hydrocarbon, which means that its molecules contain only carbon and hydrogen atoms joined only by single bonds. Saturated hydrocarbons are also known as alkanes. By far its most important use is as a solvent in a variety of industrial operations.

KEY FACTS

OTHER NAMES:

n-hexane

FORMULA:

C₆H₁₄

ELEMENTS:

Carbon, hydrogen

COMPOUND TYPE:

Alkane; saturated hydrocarbon (organic)

STATE:

Liquid

MOLECULAR WEIGHT:

86.18 g/mol

MELTING POINT:

−95.35°C (−139.6°F)

BOILING POINT:

68.73°C (155.7°F)

SOLUBILITY:

Insoluble in water; very soluble in ethyl alcohol; soluble in ether and chloroform

HOW IT IS MADE

Hexane is extracted from petroleum. Petroleum is a complex mixture of solid, liquid, and gaseous hydrocarbons that has virtually no use itself. However, the fractional distillation of petroleum produces hundreds of individual compounds, each of which has its own important commercial and industrial applications. Fractional distillation is the process by which petroleum is heated in tall towers. The components of petroleum boil off at different temperatures, rise to different heights in the tower, and are condensed at different levels above the base of the tower. As a liquid with a low boiling point, hexane boils off and rises to upper levels of the tower, where it condenses and is removed in a portion of the petroleum known as petroleum ether or ligroin. Hexane can then be separated from other constituents of petroleum ether by a second distillation, in which each component boils off and is condensed at its own distinctive boiling point.

COMMON USES AND POTENTIAL HAZARDS

By far the most important use of hexane is in solvents used for a variety of purposes, such as the extraction of oils from seeds and vegetables; as a degreaser and cleaning agent for printing equipment; as a solvent in glues such as rubber cement; as an ingredient in inks and varnishes; in the shoe and leather manufacturing industry; and in the roofing industry.

Hexane poses both safety and health risks for humans and other animals. The liquid vaporizes easily and the vapors formed ignite easily and may even explode under the proper conditions. The primary health hazard related to hexane occurs by breathing in the compound. When inhaled, it can cause numbness in the hands and feet, weakness in the feet and lower legs, paralysis of the arms and legs, muscle wasting, damage to nerves, nausea and vomiting, jaundice, skin rashes, irritation of the eyes and throat, blurred vision, mental confusion, and coma. There is no evidence, however, that hexane is carcinogenic.

Interesting Facts

• Hexane to which a red or blue dye has been added is sometimes used to make thermometers used for measuring low temperatures.

Words to Know

CARCINOGEN

A substance that causes cancer in humans or other animals.

DISTILLATION

A process of separating two or more substances by boiling the mixture of which they are composed and condensing the vapors produced at different temperatures.

SOLVENT

A liquid in which another substance is dissolved, to form a solution.

The health hazards posed by hexane are of concern in only two circumstances: among workers who handle the liquid on a regular basis; and among people who deliberately inhale the compound as part of a solvent for the purpose of getting "high." In both cases, a person is exposed to much higher concentrations of hexane that one would encounter in commercial or industrial products. The practice of glue-sniffing, which has become popular among some teenagers, can result in serious health problems, including dizziness, increased heart rate, high blood pressure, disorientation, confusion, and occasionally violent impulses or suicide attempts.

FOR FURTHER INFORMATION

"Hexane." U.S. Environmental Protection Agency Technology Transfer Network, Air Toxics Website. http://www.epa.gov/ttn/atw/hlthef/hexane.html (accessed on October 12, 2005).

Menhard, Francha Roffe. The Facts about Inhalants. New York: Benchmark Books, 2004.

"ToxFAQs for n-hexane." Agency for Toxic Substances and Disease Registry. http://www.atsdr.cdc.gov/tfacts113.html (accessed on October 12, 2005).