Geraniol
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IUPAC name
(2E)-3,7-Dimethyl-2,6-octadien-1-ol
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3D model (JSmol)
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ChEBI | |
ChEMBL | |
ChemSpider | |
ECHA InfoCard | 100.003.071 |
EC Number |
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KEGG | |
PubChem CID
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UNII | |
CompTox Dashboard (EPA)
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Properties | |
C10H18O | |
Molar mass | 154.253 g·mol−1 |
Density | 0.889 g/cm3 |
Melting point | −15 °C (5 °F; 258 K)[2] |
Boiling point | 230 °C (446 °F; 503 K)[2] |
686 mg/L (20 °C)[2] | |
log P | 3.28[3] |
Hazards | |
NFPA 704 (fire diamond) | |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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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 (in essence, geraniol lacking the terminal −OH) 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.[4] It is also commonly used as an insect repellent, especially for mosquitoes.[5]
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.[further explanation needed]
Biochemistry
Geraniol is important in biosynthesis of other terpenes. For example, myrcene and ocimene are formed by dehydration and isomerization of geraniol.[6]
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 tosylate, which is a precursor to the chloride. Geranyl chloride also arises by the Appel reaction by treating geraniol with triphenylphosphine and carbon tetrachloride.[7][8] It can be hydrogenated.[9] It can be oxidized to the aldehyde geranial.[10]
Health and safety
Geraniol is classified as D2B (Toxic materials causing other effects) using the Workplace Hazardous Materials Information System (WHMIS).[11]
Related compounds
- Citral, the corresponding aldehyde
- Nerol, the double-bond isomer
- Rhodinol, a related terpene alcohol
- Geranyl pyrophosphate
- Geranylgeranyl pyrophosphate
- Linalool, the isomer derived from transposition of the allylic alcohol
- 8-Hydroxygeraniol, produced by action of geraniol 8-hydroxylase
See also
References
- ^ "Geraniol". The Merck Index (12th ed.).
- ^ a b c Record in the GESTIS Substance Database of the Institute for Occupational Safety and Health
- ^ "Geraniol_msds".
- ^ Danka, R. G.; Williams, J. L.; Rinderer, T. E. (1990). "A bait station for survey and detection of honey bees" (PDF). Apidologie. 21 (4): 287–292. doi:10.1051/apido:19900403.
- ^ Müller, Günter C.; Junnila, Amy; Kravchenko, Vasiliy D.; Revay, Edita E.; Butler, Jerry; Orlova, Olga B.; Weiss, Robert W.; Schlein, Yosef (March 2008). "Ability of essential oil candles to repel biting insects in high and low biting pressure environments". Journal of the American Mosquito Control Association. 24 (1): 154–160. doi:10.2987/8756-971X(2008)24[154:AOEOCT]2.0.CO;2. ISSN 8756-971X. PMID 18437832.
- ^ Eggersdorfer, M. "Terpenes". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a26_205. ISBN 978-3527306732.
- ^ Stork, Gilbert; Grieco, Paul A.; Gregson, Michael (1974). "Allylic Chlorides from Allylic Alcohols: Geranyl Chloride". Organic Syntheses. 54: 68. doi:10.15227/orgsyn.054.0068.
- ^ Jose G. Calzada and John Hooz (1974). "Geranyl chloride". Organic Syntheses. 54: 63. doi:10.15227/orgsyn.054.0063.
- ^ Takaya, Hidemasa; Ohta, Tetsuo; Inoue, Shin-ichi; Tokunaga, Makoto; Kitamura, Masato; Noyori, Ryoji (1995). "Asymmetric Hydrogenation of Allylic Alcohols Using Binap-Ruthenium Complexes: (S)-(−)-citronellol". Organic Syntheses. 72: 74. doi:10.15227/orgsyn.072.0074; Collected Volumes, vol. 9, p. 169.
- ^ Piancatelli, Giovanni; Leonelli, Francesca (2006). "Oxidation Of Nerol To Neral With Iodosobenzene and TEMPO". Organic Syntheses. 83: 18. doi:10.15227/orgsyn.083.0018.
- ^ "MSDS – Geraniol". Sigma-Aldrich. Retrieved June 24, 2014.