Terpineol

alpha-Terpineol
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
98-55-5 Yes
ChEBI CHEBI:22469 Yes
ChEMBL ChEMBL507795 
ChemSpider 13850142 Yes
Jmol-3D images Image
UNII 21334LVV8W Yes
Properties
Molecular formula
 C10H18O
Molar mass 154.25 g·mol−1
Density 0.9338 g/cm3
Melting point 18 °C (64 °F; 291 K)
Boiling point 219 °C (426 °F; 492 K) (81 to 82 °C at 4.5 mmHg)
Hazards
MSDS External MSDS
NFPA 704
Flammability code 1: Must be pre-heated before ignition can occur. Flash point over 93 °C (200 °F). E.g., canola oil Health code 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g., chloroform Reactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g., liquid nitrogen Special hazards (white): no codeNFPA 704 four-colored diamond
1
2
0
Except where noted otherwise, data is given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
  verify (what is: Yes/?)
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] (+)-α-Terpineol is a chemical constituent of scullcap.

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:[3]

Terpineol synthesisfrom limonene

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

  1. ↑ Merck Index, 11th Edition, 9103
  2. ↑ 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.
  3. ↑ 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