Geraniol is a monoterpenoid and an alcohol. It is the primary part of rose oil, palmarosa oil, and citronella oil (Java type). It also occurs in small quantities in geranium, lemon, and many other essential oils. It appears as a clear to pale-yellow oil which is insoluble in water, but soluble in most common organic solvents. It has a rose-like odor, for which 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.

Use

Research has shown geraniol to be an effective plant-based insect repellent. On the other hand, it is also produced by the scent glands of honey bees to help them mark nectar-bearing flowers and locate the entrances to their hives.

Although geraniol and other flavor compounds are found naturally in well aged tobacco, geraniol is listed in a 1994 report from cigarette companies as one of the 599 additives to cigarettes to improve their flavor.

Biochemistry

The functional group based on geraniol (essentially geraniol lacking the terminal -OH) is called geranyl. It is important in biosynthesis of other terpenes. It is a by product of the metabolism of sorbate and thus is a very unpleasant contaminant of wine if bacteria are allowed to grow in wine.

Reactions

In acidic solutions, geraniol is converted to the cyclic terpene alpha-terpineol.

Health and safety

Geraniol should be avoided by people with perfume allergy.

References

See also

• Citral, the corresponding aldehyde;
• Nerol, the double bond isomer;
• Rhodinol, a related terpene alcohol.