Title: a-Terpineol
CAS Registry Number: 98-55-5
CAS Name: a,a,4-Trimethyl-3-cyclohexene-1-methanol
Additional Names: p-menth-1-en-8-ol
Molecular Formula: C10H18O
Molecular Weight: 154.25
Percent Composition: C 77.87%, H 11.76%, O 10.37%
Literature References: Terpineol exists as three isomers, a-, b-, and g-terpineol: J. L. Simonsen, The Terpenes vol. I (University Press, Cambridge, 2nd ed., 1947) pp 256-274. Isoln of d-a-terpineol from petitgrain oil: Walbaum, Hüthig, J. Prakt. Chem. 67, 322 (1903). Isoln from l-a-terpineol from long leaf pine oil: Teeple, J. Am. Chem. Soc. 30, 412 (1908). Isoln of dl-a-terpineol from cajeput oil: Voiry, Compt. Rend. 106, 1540 (1888). Synthesis of d-a-terpineol: Cologne, Crabalona, Bull. Soc. Chim. Fr. 1960, 102. Synthesis of l-a-terpineol: eidem, ibid. 1959, 1505. Stereochemistry: Henbest, McElkinney, J. Chem. Soc. 1959, 1834. Review: Wagner, Manuf. Chem. 22, 98, 153 (1951).
Derivative Type: d-Form
Properties: Liquid. bp4.5 81-82°; bp731 206-207°. d420 0.9338. nD20 1.4818. [a]D20 +92.45°. Solidifies at 31°.
Boiling point: bp4.5 81-82°; bp731 206-207°
Optical Rotation: [a]D20 +92.45°
Index of refraction: nD20 1.4818
Density: d420 0.9338
Derivative Type: Phenylurethan
Molecular Formula: C17H23NO2
Molecular Weight: 273.37
Percent Composition: C 74.69%, H 8.48%, N 5.12%, O 11.71%
Properties: Crystals from petr ether, mp 111°. [a]D20 +30.50° (benzene).
Melting point: mp 111°
Optical Rotation: [a]D20 +30.50° (benzene)
Derivative Type: l-Form
Properties: Liquid. bp5 80-81.5°. d420 0.935. nD20 1.4820. [a]D20 -100° (c = 20 in alc). Solidifies at 36.4°.
Boiling point: bp5 80-81.5°
Optical Rotation: [a]D20 -100° (c = 20 in alc)
Index of refraction: nD20 1.4820
Density: d420 0.935
Derivative Type: Dinitrobenzoate
Molecular Formula: C17H20N2O6
Molecular Weight: 348.35
Percent Composition: C 58.61%, H 5.79%, N 8.04%, O 27.56%
Properties: Crystals from alcohol, mp 101.5°. [a]D20 -31° (c = 9.5 in carbon tetrachloride).
Melting point: mp 101.5°
Optical Rotation: [a]D20 -31° (c = 9.5 in carbon tetrachloride)
Derivative Type: dl-Form
Properties: Liquid. bp3 85°; bp752 218.8-219.4°, d15 0.9386. nD20 1.4831.
Boiling point: bp3 85°; bp752 218.8-219.4°
Index of refraction: nD20 1.4831
Density: d15 0.9386
Derivative Type: Phenylurethan
Molecular Formula: C17H23NO2
Molecular Weight: 273.37
Percent Composition: C 74.69%, H 8.48%, N 5.12%, O 11.71%
Properties: Crystals, mp 113°.
Melting point: mp 113°
Use: Perfumes; denaturing fats for soap manufacture.
Therap-Cat: Antiseptic.
Keywords: Antiseptic/Disinfectant.
alpha-Terthienyl alpha-Tocotrienol alpha-Yohimbine Alpidem Alpiropride

Skeletal formula Ball-and-stick model
CAS number 98-55-5 YesY
ChemSpider 13850142 YesY
UNII 21334LVV8W YesY
ChEBI CHEBI:22469 YesY
Jmol-3D images Image 1
Molecular formula C10H18O
Molar mass 154.25 g/mol
Density 0.9338 g/cm3
Melting point 18 °C
Boiling point 219 °C
81-82 °C at 4.5 mmHg
MSDS External MSDS
NFPA 704
NFPA 704.svg
 N (verify) (what is: YesY/N?)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
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.[1] 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.[2]

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:[3]

Terpineol synthesisfrom limonene

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