Isoamyl Acetate

OVERVIEW

Isoamyl acetate (EYE-so-A-mil AS-uh-tate) is a clear, colorless liquid with a pleasant fruity odor and taste reminiscent of pears or bananas. When prepared for industrial or commercial use, it is often known as pear oil or banana oil.

HOW IT IS MADE

Isoamyl acetate is made commercially by reacting acetic acid (CH₃COOH) with amyl alcohol (C₄H₉CH₂OH) to produce amyl acetate, of which there are eight isomers. The isomers are then separated from each other by fractional distillation to obtain the one desired form, isoamyl acetate.

KEY FACTS

OTHER NAMES:

Isopentyl acetate; isoamyl ethanoate; amylacetic ester

FORMULA:

CH₃COOCH₂CH₂CH (CH₃)₂

ELEMENTS:

Carbon, hydrogen, oxygen

COMPOUND TYPE:

Ester (organic)

STATE:

Liquid

MOLECULAR WEIGHT:

130.18 g/mol

MELTING POINT:

−78.5°C (−109°F)

BOILING POINT:

142.5°C (288.5°F)

SOLUBILITY:

Slightly soluble in water; soluble in most organic solvents

COMMON USES AND POTENTIAL HAZARDS

Isoamyl acetate is a very popular additive for imparting a pleasant odor or taste to commercial products. Since 1976, the U.S. Patent Office has issued 1,174 patents for inventions that contain the compound. Some of the products to which it is added include:

• Foods and drinks, such as gum, candy, mineral water, beer, and syrups used to make soft drinks;
• Personal care products, such as perfume, nail polish, leather polish, and shoe polish;
• Furniture polish, varnishes, and lacquers; and
• Dry cleaning preparation.

In addition to these applications, isoamyl acetate has a number of other uses, including

• The fermentation of grain to produce whiskey;
• To mask unpleasant odors;
• In the manufacture of a number of industrial and household products, including bath sponges, artificial leather, artificial silk, rayon, artificial pearls, artificial glass, bronzing fluid, metallic paint, fluorescent lamps, and photographic film;
• In the dyeing and finishing of textiles; and
• As a solvent for old oil paints.

Isoamyl acetate is flammable and is rated as a severe fire hazard. It is also explosive. The chemical should not be used around open flames or sparks. People should not smoke around isoamyl acetate.

Interesting Facts

• When a bee stings, it leaves behind traces of isoamyl acetate at the site of the sting. The isoamyl acetate then attracts other bees to the same site, accounting for the tendency for an individual to receive multiple stings at the same point on his or her body.
• One species of Japanese honeybees defends itself from attacks by hornet predators by surrounding the hornet with a ball that consists primarily of isoamyl acetate. The ball becomes so hot that the hornet dies.

Words to Know

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.

ISOMER

One of two or more forms of a chemical compound with the same molecular formula, but different structural formulas and different chemical and physical properties.

Isoamyl acetate is also an irritant to the skin, eyes, and respiratory and digestive systems. If swallowed it may cause sore throat, nausea, and abdominal pain. People who work with the pure compound are at greater risk for harm from the compound than are those who use it in commercial products.

FOR FURTHER INFORMATION

"Isoamyl Acetate." International Programme on Chemical Safety. http://www.inchem.org/documents/icsc/icsc/eics0356.htm (accessed on October 12, 2005).

"Occupational Safety and Health Guideline for Isoamyl Acetate." Occupational Safety & Health Administration. http://www.osha.gov/SLTC/healthguidelines/isoamylacetate/recognition.html (accessed on October 12, 2005).

Shukla, Nutan. "Honeybees Come to Know of Queen's Death through Smell." The Tribune Spectrum. http://www.tribuneindia.com/2003/20030601/spectrum/nature.htm (accessed on October 12, 2005).

"Unusual Thermal Defence by a Honeybee against Mass Attack by Hornets." Nature (September 28, 1995): 334-336.