|3D model (Jmol)||Interactive image|
|Molar mass||154.25 g/mol|
|Density||0.858 – 0.868 g/cm3|
|Melting point||< −20 °C (−4 °F; 253 K)|
|Boiling point||198 to 199 °C (388 to 390 °F; 471 to 472 K)|
|Flash point||55 °C (131 °F; 328 K)|
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
|what is ?)(|
Linalool (/, , , , / or //) refers to two enantiomers of a naturally occurring terpene alcohol found in many flowers and spice plants. These have multiple commercial applications, the majority of which are based on its pleasant scent (floral, with a touch of spiciness). It has other names such as β-linalool, linalyl alcohol, linaloyl oxide, p-linalool, allo-ocimenol, and 3,7-dimethyl-1,6-octadien-3-ol.
Over 200 species of plants produce linalool, mainly from the families Lamiaceae (mint and other herbs), Lauraceae (laurels, cinnamon, rosewood), and Rutaceae (citrus fruits), but also birch trees and other plants, from tropical to boreal climate zones. It has also been found in some fungi and cannabis.
Both enantiomeric forms are found in nature: (S)-linalool is found, for example, as a major constituent of the essential oils of coriander (Coriandrum sativum L. family Apiaceae) seed, palmarosa [Cymbopogon martinii var martinii (Roxb.) Wats., family Poaceae], and sweet orange (Citrus sinensis Osbeck, family Rutaceae) flowers. (R)-linalool is present in lavender (Lavandula officinalis Chaix, family Lamiaceae), bay laurel (Laurus nobilis, family Lauraceae), and sweet basil (Ocimum basilicum, family Lamiaceae), among others.
Each enantiomer evokes different neural responses in humans, and therefore are classified as possessing distinct scents. (S)-(+)-Linalool is perceived as sweet, floral, petitgrain-like (odor threshold 7.4 ppb) and the (R)-form as more woody and lavender-like (odor threshold 0.8 ppb).
In higher plants, linalool, as other monoterpenoids, is produced from isopentenyl pyrophosphate via the universal isoprenoid intermediate geranyl pyrophosphate, through a class of membrane-bound enzymes named monoterpene synthases. One of these, linalool synthase (LIS), has been reported to produce (S)-linalool in several floral tissues.
Linalool is used in some mosquito-repellent products; however, the EPA notes that "a preliminary screen of labels for products containing [l]inalool (as the sole active ingredient) indicates that efficacy data on file with the Agency may not support certain claims to repel mosquitos."
Plants that contain linalool
- Cinnamomum tamala
- Cannabis sativa
- Cannabis indica
- Ocimum basilicum
- Solidago Meyen, Solidago chilensis
- Artemisia vulgaris (mugwort)
- Humulus lupulus
Linalool gradually breaks down when in contact with oxygen, forming an oxidized by-product that may cause allergic reactions such as eczema in susceptible individuals. Between 5 and 7% of patients undergoing patch testing in Sweden were found to be allergic to the oxidized form of linalool.
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