Geraniol


Geraniol is a monoterpenoid and an alcohol. It is the primary component of rose oil, palmarosa oil, and citronella oil. It is a colorless oil, although commercial samples can appear yellow. It has low solubility in water, but it is soluble in common organic solvents. The functional group derived from geraniol is called geranyl.

Uses and occurrence

In addition to rose oil, palmarosa oil, and citronella oil, it also occurs in small quantities in geranium, lemon, and many other essential oils. With a rose-like scent, it is commonly used in perfumes. It is used in flavors such as peach, raspberry, grapefruit, red apple, plum, lime, orange, lemon, watermelon, pineapple, and blueberry.
Geraniol is produced by the scent glands of honeybees to mark nectar-bearing flowers and locate the entrances to their hives. It is also commonly used as an insect repellent, especially for mosquitoes.
It is a byproduct of the metabolism of sorbate and, thus, is a very unpleasant contaminant of wine if bacteria are allowed to grow in it.

Biochemistry

Geraniol is important in biosynthesis of other terpenes. For example, myrcene and ocimene are formed by dehydration and isomerization of geraniol.

Reactions

In acidic solutions, geraniol is converted to the cyclic terpene α-terpineol. The alcohol group undergoes expected reactions. It can be converted to the chloride with thionyl chloride. It can be hydrogenated. It can be oxidized to the aldehyde geranial.

Health and safety

Geraniol is classified as D2B using the Workplace Hazardous Materials Information System.

Related compounds