Geraniol: Difference between revisions

{{Short description|Monoterpenoid and alcohol that is the primary component of citronella oil}}

{{dist|Geranial}}

|Verifiedfields = changed

|Watchedfields = changed

|verifiedrevid = 443834400

|Reference = <ref>{{cite book|entry=Geraniol|title=The Merck Index|edition=12th|title-link=The Merck Index}}</ref>

|Name = Geraniol

|ImageFile = Geraniol structure.png

|ImageSize = 200px

|ImageName = Geraniol

|ImageFile2 = Geraniol-3D-balls-B.png

|ImageSize2 = 200px

|PIN = (2''E'')-3,7-Dimethylocta-2,6-dien-1-ol

|OtherNames =

|Section1 = {{Chembox Identifiers

|IUPHAR_ligand = 2467

|ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}

|ChemSpiderID = 13849989

|InChI = 1/C10H18O/c1-9(2)5-4-6-10(3)7-8-11/h5,7,11H,4,6,8H2,1-3H3/b10-7+

|InChIKey = GLZPCOQZEFWAFX-JXMROGBWBZ

|StdInChI_Ref = {{stdinchicite|correct|chemspider}}

|StdInChI = 1S/C10H18O/c1-9(2)5-4-6-10(3)7-8-11/h5,7,11H,4,6,8H2,1-3H3/b10-7+

|StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}

|StdInChIKey = GLZPCOQZEFWAFX-JXMROGBWSA-N

|CASNo_Ref = {{cascite|correct|CAS}}

|PubChem = 637566

|ChEMBL_Ref = {{ebicite|correct|EBI}}

|ChEMBL = 25719

|CASNo = 106-24-1

|EINECS = 203-377-1

|UNII_Ref = {{fdacite|correct|FDA}}

|UNII = L837108USY

|ChEBI_Ref = {{ebicite|correct|EBI}}

|ChEBI = 17447

|KEGG = C01500

|DrugBank = DB14183

|SMILES = CC(=CCC/C(=C/CO)/C)C

}}

|Section2 = {{Chembox Properties

|C=10 |H=18 |O=1

|Density = 0.889 g/cm³

|MeltingPtC = -15

|MeltingPt_ref = <ref name=GESTIS>{{GESTIS|ZVG = 491258}}</ref>

|BoilingPtC = 230

|BoilingPt_ref = <ref name=GESTIS/>

|Solubility = 686 mg/L (20&nbsp;°C)<ref name=GESTIS/>

|LogP =3.28<ref name="chemsrc">{{Cite web|url=https://www.chemsrc.com/en/cas/106-24-1_125147.html|title=Geraniol_msds}}</ref>

}}

|Section3 = {{Chembox Hazards

|NFPA-H = 2

|NFPA-F = 1

|NFPA-R = 0

}}<ref>{{cite web|url=https://cameochemicals.noaa.gov/chemical/20432|title= GERANIOL - Cameo Chemicals - NOAA |access-date=26 June 2021}}</ref>

|Section4 =

|Section5 =

|Section6 =

'''Geraniol''' is a [[monoterpenoid]] and an [[Alcohol (chemistry)|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 [[hydroxyl|−OH]]) is called '''geranyl'''.

==Uses and occurrence==

In addition to [[rose oil]], [[palmarosa]] oil, and [[citronella oil]], it also occurs in small quantities in [[Pelargonium|geranium]], [[lemon]], and many other [[essential oil]]s. With a [[rose]]-like scent, it is commonly used in [[perfume]]s and in scents such as [[peach]], [[raspberry]], [[grapefruit]], [[apple|red apple]], [[plum]], [[lime (fruit)|lime]], [[Orange (fruit)|orange]], [[lemon]], [[watermelon]], [[pineapple]], and [[blueberry]].

Geraniol is produced by the [[Nasonov's gland|scent glands]] of [[honeybee]]s to mark nectar-bearing flowers and locate the entrances to their hives.<ref>{{cite journal |first1=R. G. |last1=Danka |first2=J. L. |last2=Williams |first3=T. E. |last3=Rinderer | title = A bait station for survey and detection of honey bees | journal = Apidologie | volume = 21 | issue = 4 | pages = 287–292 | year = 1990 | doi = 10.1051/apido:19900403| url = https://hal.archives-ouvertes.fr/hal-00890837/file/hal-00890837.pdf | doi-access = free }}</ref> It is also commonly used as an insect repellent, especially for mosquitoes.<ref>{{Cite journal|last1=Müller|first1=Günter C.|last2=Junnila|first2=Amy|last3=Kravchenko|first3=Vasiliy D.|last4=Revay|first4=Edita E.|last5=Butler|first5=Jerry|last6=Orlova|first6=Olga B.|last7=Weiss|first7=Robert W.|last8=Schlein|first8=Yosef|date=March 2008|title=Ability of essential oil candles to repel biting insects in high and low biting pressure environments|url=https://pubmed.ncbi.nlm.nih.gov/18437832/|journal=Journal of the American Mosquito Control Association|volume=24|issue=1|pages=154–160|doi=10.2987/8756-971X(2008)24[154:AOEOCT]2.0.CO;2|issn=8756-971X|pmid=18437832|s2cid=41927381 }}</ref>

The scent of geraniol is reminiscent of, but chemically unrelated to, 2-ethoxy-3,5-hexadiene, also known as [[Wine fault#Geranium taint|geranium taint]], a wine fault resulting from fermentation of [[sorbic acid]] by [[lactic acid bacteria]].<ref>Holcombe, Luke (9 January 2018) [https://aggie-horticulture.tamu.edu/vitwine/files/2018/03/Wine-Faults.pdf "Wine faults"] {{Webarchive|url=https://web.archive.org/web/20210916114943/https://aggie-horticulture.tamu.edu/vitwine/files/2018/03/Wine-Faults.pdf |date=2021-09-16 }}, p. 11.</ref>

[[Geranyl pyrophosphate]] is important in [[biosynthesis]] of other [[terpene]]s such as [[myrcene]] and [[ocimene]].<ref name=UllmannEgg>{{Ullmann|first=M.|last=Eggersdorfer|title=Terpenes|doi=10.1002/14356007.a26_205}}</ref> It is also used in the [[biosynthesis]] pathway of many [[cannabinoids]] in the form of [[Cannabigerolic acid|CBGA]].<ref name="pmid9607329">{{cite journal | vauthors = Fellermeier M, Zenk MH | title = Prenylation of olivetolate by a hemp transferase yields cannabigerolic acid, the precursor of tetrahydrocannabinol | journal = FEBS Letters | volume = 427 | issue = 2 | pages = 283–85 | date = May 1998 | pmid = 9607329 | doi = 10.1016/S0014-5793(98)00450-5 | doi-access = free }}</ref>

In [[acidic]] solutions, geraniol is converted to the cyclic terpene [[terpineol|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.<ref>{{OrgSynth|title=Allylic Chlorides from Allylic Alcohols: Geranyl Chloride|first1=Gilbert |last1=Stork |first2=Paul A. |last2=Grieco |first3=Michael |last3=Gregson |year=1974|volume=54|page=68|doi=10.15227/orgsyn.054.0068}}</ref><ref>{{OrgSynth | author = Jose G. Calzada and John Hooz | title = Geranyl chloride| volume = 54 | pages = 63 | year=1974|doi = 10.15227/orgsyn.054.0063}}</ref> It can be hydrogenated.<ref>{{OrgSynth|title=Asymmetric Hydrogenation of Allylic Alcohols Using BINAP–Ruthenium Complexes: (''S'')-(−)-citronellol|first1=Hidemasa |last1=Takaya |first2=Tetsuo |last2=Ohta |first3=Shin-ichi |last3=Inoue |first4=Makoto |last4=Tokunaga |first5=Masato |last5=Kitamura |author6-link=Ryoji Noyori |first6=Ryoji |last6=Noyori |year=1995|volume=72|page=74|collvol=9|collvolpages=169|doi=10.15227/orgsyn.072.0074}}</ref> It can be oxidized to the aldehyde [[Citral|geranial]].<ref>{{OrgSynth|title=Oxidation of Nerol to Neral With Iodosobenzene and TEMPO |first1=Giovanni |last1=Piancatelli |first2=Francesca |last2=Leonelli |year=2006|volume=83|page=18|doi=10.15227/orgsyn.083.0018}}</ref>

==Health and safety==

Geraniol is classified as D2B (Toxic materials causing other effects) using the [[Workplace Hazardous Materials Information System]] (WHMIS).<ref>{{cite web|url=https://www.sigmaaldrich.com/US/en/product/aldrich/163333 |title=MSDS – Geraniol |publisher=Sigma-Aldrich |access-date= Feb 15, 2022}}</ref>

== History ==

Geraniol was first isolated in pure form in 1871 by the German chemist [[:de:Oscar Jacobsen|Oscar Jacobsen]] (1840–1889).<ref>{{cite journal |last1=Jacobsen |first1=Oscar |title=Untersuchung der indischen Geraniumöls |journal=Annalen der Chemie und Pharmacie |date=1871 |volume=157 |pages=232–239 |url=https://babel.hathitrust.org/cgi/pt?id=uva.x002457983&view=1up&seq=244 |trans-title=InvestIgation of Indian oil from geranium [grass] |language=German}} 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 … )</ref><ref>{{cite book |last1=Semmler |first1=F.W. |title=Die ätherischen Öle |trans-title=The Volatile Oils |date=1906 |publisher=Von Veit & Co. |location=Leipzig, Germany |volume=1 |page=292 |url=https://archive.org/details/b28089595_0001/page/292/mode/2up |language=German}} 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.</ref> Using [[distillation]], Jacobsen obtained geraniol from an essential oil which was obtained from geranium grass (''[[Cymbopogon schoenanthus|Andropogon schoenanthus]]'') and which was produced in India.<ref>(Semmler, 1906), p. 491.</ref> The chemical structure of geraniol was determined in 1919 by the French chemist Albert Verley (1867–1959).<ref>{{cite journal |last1=Verley |first1=Albert |title=Sur la constitution du géraniol, du linalool et du nérol |journal=Bulletin de la Société Chimique de France |date=1919 |volume=25 |pages=68–80 |url=https://babel.hathitrust.org/cgi/pt?id=iau.31858002467680&view=1up&seq=78 |series=4th series |trans-title=On the chemical structure of geraniol, linalool, and nerol |language=French}} The chemical structure of geraniol appears on p. 70.</ref>

==See also==

*[[Citronellol]]

*[[Citral]]

*[[Nerol]]

*[[Rhodinol]]

*[[Geranyl pyrophosphate]]

*[[Geranylgeranyl pyrophosphate]]

*[[Linalool]]

*[[8-Hydroxygeraniol]]

*[[Geraniol 8-hydroxylase]]

*[[Bergamottin]]

*[[Perfume allergy]]

*[http://gmd.mpimp-golm.mpg.de/Spectrums/3a24b562-4124-4405-af12-a5ab43c97740.aspx Geraniol MS Spectrum]

*[http://www.thegoodscentscompany.com/data/rw1006991.html Geraniol properties, animations, links]

{{Transient receptor potential channel modulators}}

{{Authority control}}

[[Category:Primary alcohols]]

[[Category:Alkene derivatives]]

[[Category:Flavors]]

[[Category:Insect repellents]]