Isoamyl acetate

Isoamyl acetate
IUPAC name	3-methyl-1-butyl acetate
Other names	isopentyl acetate banana oil isopentyl ethanoate pear essence 3-methylbutyl acetate 3-methylbutyl ethanoate
Identifiers
CAS number	123-92-2 Y
SMILES	CC(C)CCOC(C)=O
Properties
Molecular formula	C7H14O2
Molar mass	130.19 g/mol
Density	0.876 g/cm3
Melting point	−78 °C, 195 K, -108 °F
Boiling point	142 °C, 415 K, 288 °F
Hazards
NFPA 704	3 1 0
Flash point	25 °C
Y (what is this?)  (verify) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Isoamyl acetate, also known as isopentyl acetate, is an organic compound that is the ester formed from isoamyl alcohol and acetic acid. It is a clear colorless liquid that is only slightly soluble in water, but very soluble in most organic solvents.

Isoamyl acetate has a strong odor (similar to Juicy Fruit or a pear drop) which is also described as similar to both banana and pear. Banana oil is a term that is applied either to pure isoamyl acetate or to flavorings that are mixtures of isoamyl acetate, amyl acetate, nitrocellulose and other flavors. Pear oil commonly refers to a solution of isoamyl acetate in ethanol that is used as an artificial flavor.

Isoamyl acetate is also used to test the effectiveness of respirators or gas masks because it has a strong smell which is generally not experienced as unpleasant and that can be detected at low concentrations, and has low toxicity.

It is also used as a solvent for some varnishes and nitrocellulose lacquers, as well as being a honey bee pheromone and can be used to attract large groups of honeybees to a small area.

Isoamyl acetate is released by a honey bee's sting apparatus where it serves as a pheromone beacon to attract other bees and provoke them to sting. ^[1]

As a solvent and carrier for materials such as nitrocellulose, it was extensively used in the aircraft industry for stiffening and wind-proofing fabric flying surfaces, where it and its derivatives were generally known as 'dope'. Now that most aircraft are all-metal, such use is now limited to model aircraft, where it is still popularly used for strengthening tissue coverings and balsa wood.

Laboratory synthesis

Isoamyl acetate can be prepared in the laboratory by the acid catalyzed Fischer esterification reaction between isoamyl alcohol and glacial acetic acid as shown in the reaction equation below. Typically, concentrated sulfuric acid is used as the catalyst. The reactants are refluxed in order to promote the reaction, the acid is neutralized and extracted, and the product is dried, then distilled.

References