Terpineol

*alpha*-Terpineol
Skeletal formula	Ball-and-stick model
Names
	IUPAC name 2-(4-Methyl-1-cyclohex-3-enyl)propan-2-ol
	Other names alpha-Terpineol ; α-Terpineol ; p-Menth-1-en-8-ol ; α,α,4-Trimethylcyclohex-3-ene-1-methanol ; Terpene alcohol
Identifiers
CAS Number	98-55-5 ;
3D model (JSmol)	Interactive image;
ChEBI	CHEBI:22469 ;
ChEMBL	ChEMBL507795 ;
ChemSpider	13850142 ;
UNII	21334LVV8W ;
	InChI InChI=1S/C10H18O/c1-8-4-6-9(7-5-8)10(2,3)11/h4,9,11H,5-7H2,1-3H3 Key: WUOACPNHFRMFPN-UHFFFAOYSA-N ; InChI=1/C10H18O/c1-8-4-6-9(7-5-8)10(2,3)11/h4,9,11H,5-7H2,1-3H3 Key: WUOACPNHFRMFPN-UHFFFAOYAL;
	SMILES C\C1=C\CC(CC1)C(O)(C)C;
Properties
Chemical formula	C10H18O
Molar mass	154.253 g·mol−1
Appearance	Colorless liquid
Density	0.93 g/cm3
Melting point	−35.9 to −28.2 °C (−32.6 to −18.8 °F; 237.2 to 245.0 K) (mixture of isomers)
Boiling point	214–217 °C (417–423 °F; 487–490 K) (mixture of isomers)
Solubility in water	2.42 g/L
Hazards
NFPA 704 (fire diamond)	2 1 0
Flash point	88 °C (190 °F; 361 K)
Safety data sheet (SDS)	External MSDS
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). verify (what is ?) Infobox references

Terpineol is a naturally occurring monoterpene alcohol that has been isolated from a variety of sources such as cajuput oil, pine oil, and petitgrain oil.^[2] There are four isomers, alpha-, beta-, gamma-terpineol, and terpinen-4-ol. beta- and gamma-terpineol differ only by the location of the double bond. Terpineol is usually a mixture of these isomers with alpha-terpineol as the major constituent.

Terpineols: alpha-, beta-, gamma-, and the 4-terpineol isomer

Terpineol has a pleasant odor similar to lilac and is a common ingredient in perfumes, cosmetics, and flavors. α-Terpineol is one of the two most abundant aroma constituents of lapsang souchong tea; the α-terpineol originates in the pine smoke used to dry the tea.^[3] (+)-α-Terpineol is a chemical constituent of skullcap.

Synthesis

Although it is naturally occurring, terpineol is commonly manufactured from the more readily available alpha-pinene.

In one study, an alternative route starting from d-limonene was demonstrated:^[4]

Limonene is reacted with trifluoroacetic acid in a Markovnikov addition to a trifluoroacetate intermediate, which is easily hydrolyzed with sodium hydroxide to α-terpineol with 76% selectivity. Side-products are the β-terpineol in a mixture of the cis-isomer, the trans-isomer, and 4-terpineol.

References

^ ^a ^b ^c ^d ^e ^f Record in the GESTIS Substance Database of the Institute for Occupational Safety and Health
^ Merck Index, 11th Edition, 9103
^ Shan-Shan Yao; Wen-Fei Guo; Yi Lu; Yuan-Xun Jiang (2005). "Flavor Characteristics of Lapsang Souchong and Smoked Lapsang Souchong, a Special Chinese Black Tea with Pine Smoking Process". Journal of Agricultural and Food Chemistry. 53 (22): 8688–93. doi:10.1021/jf058059i. PMID 16248572.
^ Yuasa, Yoshifumi; Yuasa, Yoko (2006). "A Practical Synthesis ofd-α-Terpineol via Markovnikov Addition ofd-Limonene Using Trifluoroacetic Acid". Organic Process Research & Development. 10 (6): 1231–1232. doi:10.1021/op068012d.

External links

MSDS for alpha-terpineol
Media related to Terpineols at Wikimedia Commons

[GESTIS-1] ^ ^a ^b ^c ^d ^e ^f Record in the GESTIS Substance Database of the Institute for Occupational Safety and Health

[2] Merck Index, 11th Edition, 9103

[3] Shan-Shan Yao; Wen-Fei Guo; Yi Lu; Yuan-Xun Jiang (2005). "Flavor Characteristics of Lapsang Souchong and Smoked Lapsang Souchong, a Special Chinese Black Tea with Pine Smoking Process". Journal of Agricultural and Food Chemistry. 53 (22): 8688–93. doi:10.1021/jf058059i. PMID 16248572.

[4] Yuasa, Yoshifumi; Yuasa, Yoko (2006). "A Practical Synthesis ofd-α-Terpineol via Markovnikov Addition ofd-Limonene Using Trifluoroacetic Acid". Organic Process Research & Development. 10 (6): 1231–1232. doi:10.1021/op068012d.

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