Linalool

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Linalool
Skeletal formula
Ball-and-stick model
Names
Preferred IUPAC name
3,7-Dimethylocta-1,6-dien-3-ol
Identifiers
  • Compounds
  • (±)-linalool
  • (R): (−)-linalool
  • (S): (+)-linalool
3D model (JSmol)
ChEBI
ChemSpider
ECHA InfoCard 100.001.032
UNII
Properties
C10H18O
Molar mass 154.25 g/mol
Density 0.858 to 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)
1.589 g/l
Hazards
NFPA 704
Flammability code 2: Must be moderately heated or exposed to relatively high ambient temperature before ignition can occur. Flash point between 38 and 93 °C (100 and 200 °F). E.g., diesel fuel Health code 1: Exposure would cause irritation but only minor residual injury. E.g., turpentine Reactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g., liquid nitrogen Special hazards (white): no codeNFPA 704 four-colored diamond
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).
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Infobox references

Linalool (/lɪˈnælˌɒl, l-, -lˌɔːl, -ləˌwɒl, -ləˌwl/ or /ˌlɪnəˈll/[1][2]) 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.

Nature[edit]

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, including fungi.[3]

Enantiomers[edit]

(S)-(+)-linalool (left) and (R)-(–)-linalool (right)

Linalool has a stereogenic center at C3 and therefore there are two stereoisomers: (R)-(–)-linalool is also known as licareol and (S)-(+)-linalool is also known as coriandrol.

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).

Biosynthesis[edit]

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.

Uses[edit]

Linalool is used as a scent in 60% to 80% of perfumed hygiene products and cleaning agents including soaps, detergents, shampoos, and lotions.[4]

It is also used as a chemical intermediate. One common downstream product of linalool is vitamin E.

In addition, linalool is used by pest professionals as a flea, fruit fly and cockroach insecticide. It can also be used a method of pest control for codling moths. Linalool create a synergistic effect with the codling moth's phermone called codlemone, which increases attraction of males.[5]

Linalool is used in some mosquito-repellent products;[6] 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."[7]

Plants that contain linalool[edit]

Safety and potential toxicity[edit]

Linalool can be absorbed by inhalation of its aerosol and by oral intake or skin absorption, potentially causing irritation, pain and allergic reactions.[3] Between 5% and 7% of patients undergoing patch testing in Sweden were found to be allergic to the oxidized form of linalool.[4] Upon inhalation, it may also cause drowsiness or dizziness.[3]

See also[edit]

References[edit]

  1. ^ "Linalool". Dictionary.com Unabridged. Random House. Retrieved 2016-01-22. 
  2. ^ "Linalool". Merriam-Webster Dictionary. Retrieved 2016-01-22. 
  3. ^ a b c "Linalool". PubChem, US National Library of Medicine. 12 February 2017. Retrieved 14 February 2017. 
  4. ^ a b "Widely Used Fragrance Ingredients In Shampoos And Conditioners Are Frequent Causes Of Eczema". MedicalNewsToday. March 28, 2009. 
  5. ^ Yang, Zhihua; Bengtsson, Marie; Witzgall, Peter (2004-03-01). "Host Plant Volatiles Synergize Response to Sex Pheromone in Codling Moth, Cydia pomonella". Journal of Chemical Ecology. 30 (3): 619–629. doi:10.1023/b:joec.0000018633.94002.af. ISSN 0098-0331. 
  6. ^ "What to look for when you're buying mosquito repellent". South China Morning Post. September 6, 2015. Retrieved December 30, 2015. 
  7. ^ EPA Linalool Summary Document Registration Review: Initial Docket (PDF) April 2007
  8. ^ Kasper, S.; Gastpar, M.; Muller, W. E.; Volz, H. P.; Moller, H. J.; Dienel, A. Hüsnü; et al. (2010). "Silexan, an orally administered Lavandula oil preparation, is effective in the treament of 'sybsyndromal' anxiety disorder: a randomized, double-blind, placebo controlled trail". International clinical psychopharmacology. 25 (5): 277–87. doi:10.1097/YIC.0b013e32833b3242. PMID 20512042. 
  9. ^ Ahmed, Aftab; Choudhary, M. Iqbal; Farooq, Afgan; Demirci, Betül; Demirci, Fatih; Can Başer, K. Hüsnü; et al. (2000). "Essential oil constituents of the spice Cinnamomum tamala (Ham.) Nees & Eberm". Flavour and Fragrance Journal. 15 (6): 388–390. doi:10.1002/1099-1026(200011/12)15:6<388::AID-FFJ928>3.0.CO;2-F. 
  10. ^ Klimánková, Eva; Holadová, Kateřina; Hajšlová, Jana; Čajka, Tomáš; Poustka, Jan; Koudela, Martin; et al. (2008). "Aroma profiles of five basil (Ocimum basilicum L.) cultivars grown under conventional and organic conditions". Food Chemistry. 107 (1): 464–472. doi:10.1016/j.foodchem.2007.07.062. 
  11. ^ Vila, R.; Mundina, M.; Tomi, F. L.; Furlán, R.; Zacchino, S.; Casanova, J.; Cañigueral, S. (2002). "Composition and Antifungal Activity of the Essential Oil of Solidago chilensis". Planta Medica. 68 (2): 164–167. doi:10.1055/s-2002-20253. PMID 11859470. 

External links[edit]