Geraniol

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Geraniol [1]
Geraniol Geraniol structure.png
Geraniol
Geraniol-3D-balls-B.png
Names
Preferred IUPAC name
(2E)-3,7-Dimethylocta-2,6-dien-1-ol
Identifiers
3D model (JSmol)
ChEBI
ChEMBL
ChemSpider
DrugBank
ECHA InfoCard 100.003.071 OOjs UI icon edit-ltr-progressive.svg
EC Number
  • 203-377-1
KEGG
PubChem CID
UNII
  • InChI=1S/C10H18O/c1-9(2)5-4-6-10(3)7-8-11/h5,7,11H,4,6,8H2,1-3H3/b10-7+ Yes check.svgY
    Key: GLZPCOQZEFWAFX-JXMROGBWSA-N Yes check.svgY
  • InChI=1/C10H18O/c1-9(2)5-4-6-10(3)7-8-11/h5,7,11H,4,6,8H2,1-3H3/b10-7+
    Key: GLZPCOQZEFWAFX-JXMROGBWBZ
  • CC(=CCC/C(=C/CO)/C)C
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)
NFPA 704.svgHealth 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g. chloroformFlammability 1: Must be pre-heated before ignition can occur. Flash point over 93 °C (200 °F). E.g. canola oilInstability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
2
1
0
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
X mark.svgN  verify  (what is  Yes check.svgYX mark.svgN ?)

Geraniol is a monoterpenoid and an alcohol. It is the primary component of citronella oil and is a primary component of rose oil and palmarosa 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.

Contents

Uses and occurrence

In addition to being found in 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 and in scents 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. [5] It is also commonly used as an insect repellent, especially for mosquitoes. [6]

The scent of geraniol is reminiscent of, but chemically unrelated to, 2-ethoxy-3,5-hexadiene, also known as geranium taint, a wine fault resulting from fermentation of sorbic acid by lactic acid bacteria. [7]

Geranyl pyrophosphate is important in biosynthesis of other terpenes such as myrcene and ocimene. [8] It is also used in the biosynthesis pathway of many cannabinoids in the form of CBGA. [9]

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. [10] [11] It can be oxidized to the aldehyde geranial. [12] Hydrogenation of the two C=C bonds over a nickel catalyst gives tetrahydrogeraniol. [13] [14]

Health and safety

Geraniol is classified as D2B (Toxic materials causing other effects) using the Workplace Hazardous Materials Information System (WHMIS). [15]

History

Geraniol was first isolated in pure form in 1871 by the German chemist Oscar Jacobsen (1840–1889). [16] [17] Using distillation, Jacobsen obtained geraniol from an essential oil produced in India which was obtained from the so-called geranium grass. [18] This essence, after which the compound was named, was a 50% cheaper substitute for the essence of the proper geranium flower with a similar, although less delicate, odor. [19]

The chemical structure of geraniol was determined in 1919 by the French chemist Albert Verley (1867–1959). [20]

See also

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<span class="mw-page-title-main">Linalool</span> Chemical compound with a floral aroma

Linalool refers to two enantiomers of a naturally occurring terpene alcohol found in many flowers and spice plants. Together with geraniol, nerol, citronellol, linalool is one of the rose alcohols. Linalool has multiple commercial applications, the majority of which are based on its pleasant scent.

<span class="mw-page-title-main">Appel reaction</span> Organic reaction in chemistry

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<span class="mw-page-title-main">Rose oil</span> Essential oil extracted from rose petals

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<span class="mw-page-title-main">Pinene</span> Oily organic chemical found in plants

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<span class="mw-page-title-main">Myrcene</span> Chemical compound

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<span class="mw-page-title-main">Citronellol</span> Pair of enantiomers

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<span class="mw-page-title-main">Nerol</span> Chemical compound

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<span class="mw-page-title-main">Farnesol</span> Chemical compound

Farnesol is a natural 15-carbon organic compound which is an acyclic sesquiterpene alcohol. Under standard conditions, it is a colorless liquid. It is hydrophobic, and thus insoluble in water, but miscible with oils. As the pyrophosphate ester, farnesol is a precursor to many terpenes and terpenoids.

<span class="mw-page-title-main">Geranyl pyrophosphate</span> Chemical compound

Geranyl pyrophosphate (GPP), also known as geranyl diphosphate (GDP), is the pyrophosphate ester of the terpenoid geraniol. Its salts are colorless. It is a precursor to many thousands of natural products.

α-Pinene Chemical compound

α-Pinene is an organic compound of the terpene class. It is one of the two isomers of pinene, the other being β-pinene. An alkene, it contains a reactive four-membered ring. It is found in the oils of many species of coniferous trees, notably Pinus and Picea species. It is also found in the essential oil of rosemary and Satureja myrtifolia. Both enantiomers are known in nature; (1S,5S)- or (−)-α-pinene is more common in European pines, whereas the (1R,5R)- or (+)-α-isomer is more common in North America. The enantiomers' racemic mixture is present in some oils such as eucalyptus oil and orange peel oil.

<span class="mw-page-title-main">Geranyl acetate</span> Chemical compound

Geranyl acetate is a terpenoid. It is a colorless liquid with a pleasant floral or fruity rose aroma. It is a colorless liquid but commercial samples can appear yellowish. Geranyl acetate is insoluble in water but soluble in organic solvents. Several hundred tons are produced annually.

Monoterpenes are a class of terpenes that consist of two isoprene units and have the molecular formula C10H16. Monoterpenes may be linear (acyclic) or contain rings (monocyclic and bicyclic). Modified terpenes, such as those containing oxygen functionality or missing a methyl group, are called monoterpenoids. Monoterpenes and monoterpenoids are diverse. They have relevance to the pharmaceutical, cosmetic, agricultural, and food industries.

<span class="mw-page-title-main">Terpineol</span> Chemical compound

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Terpene alcohol may refer to a variety of terpenoids, i.e. terpenes modified with one or more hydroxy groups:

References

  1. ↑ "Geraniol". The Merck Index (12th ed.).
  2. 1 2 3 Record in the GESTIS Substance Database of the Institute for Occupational Safety and Health
  3. ↑ "Geraniol_msds".
  4. "GERANIOL - Cameo Chemicals - NOAA" . Retrieved 26 June 2021.
  5. ↑ 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 .
  6. ↑ 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. S2CID   41927381.
  7. ↑ Holcombe, Luke (9 January 2018) "Wine faults" Archived 2021-09-16 at the Wayback Machine , p. 11.
  8. ↑ Eggersdorfer, M. "Terpenes". Ullmann's Encyclopedia of Industrial Chemistry . Weinheim: Wiley-VCH. doi:10.1002/14356007.a26_205. ISBN   978-3-527-30673-2.
  9. ↑ Fellermeier M, Zenk MH (May 1998). "Prenylation of olivetolate by a hemp transferase yields cannabigerolic acid, the precursor of tetrahydrocannabinol". FEBS Letters. 427 (2): 283–85. Bibcode:1998FEBSL.427..283F. doi: 10.1016/S0014-5793(98)00450-5 . PMID   9607329.
  10. ↑ 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 .
  11. ↑ Jose G. Calzada and John Hooz (1974). "Geranyl chloride". Organic Syntheses . 54: 63. doi:10.15227/orgsyn.054.0063 .
  12. ↑ Piancatelli, Giovanni; Leonelli, Francesca (2006). "Oxidation of Nerol to Neral With Iodosobenzene and TEMPO". Organic Syntheses . 83: 18. doi:10.15227/orgsyn.083.0018 .
  13. ↑ 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.
  14. ↑ Panten, Johannes; Surburg, Horst (2015). "Flavors and Fragrances, 2. Aliphatic Compounds". Ullmann's Encyclopedia of Industrial Chemistry. pp. 1–55. doi:10.1002/14356007.t11_t01. ISBN   978-3-527-30673-2.
  15. ↑ "MSDS – Geraniol". Sigma-Aldrich. Retrieved Feb 15, 2022.
  16. ↑ Jacobsen, Oscar (1871). "Untersuchung der indischen Geraniumöls" [InvestIgation of Indian oil from geranium [grass]]. Annalen der Chemie und Pharmacie (in German). 157: 232–239. Jacobsen named geraniol on p. 234: "Danach ist dieser Körper, das Geraniol, isomer mit dem Borneol … " (Accordingly this body [i.e., substance], geraniol, is isomeric with borneol … )
  17. ↑ Semmler, F.W. (1906). Die ätherischen Öle [The Volatile Oils] (in German). Vol. 1. Leipzig, Germany: Von Veit & Co. p. 292. From p. 292: "Von dem Geraniol ist zu erwähnen, daß … erst Jacobsen (A. 157, 232) brachte im Jahre 1870 über den Alkohol, den er Geraniol nannte, nähere Angaben, er stellte die Formel C10H18O auf, ohne weitere Konstitionsangaben zu machen." (It should be mentioned about geraniol that … Jacobsen (A. 157, 232) first gathered in 1870 more detailed data about the alcohol, which he named geraniol ; he established its [empirical] formula C10H18O, without providing further data about its chemical structure.) See also: § 49. Geraniol C10H18O, pp. 439-493. On p. 439, two hypothetical structures of geraniol are proposed.
  18. ↑ (Semmler, 1906), p. 491.
  19. ↑ Askinson, George William (1892). Perfumes and Their Preparation. N.W. Henley. pp. 123–124, 154.
  20. ↑ Verley, Albert (1919). "Sur la constitution du géraniol, du linalool et du nérol" [On the chemical structure of geraniol, linalool, and nerol]. Bulletin de la Société Chimique de France. 4th series (in French). 25: 68–80. The chemical structure of geraniol appears on p. 70.
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