Terpineol
Encyclopedia
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. There are three isomer
s, alpha-, beta-, and gamma-terpineol, the last two differing only by the location of the double bond
. Terpineol is usually a mixture of these isomers with alpha-terpineol as the major constituent.
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.
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:
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.
Monoterpene
Monoterpenes are a class of terpenes that consist of two isoprene units and have the molecular formula C10H16. Monoterpenes may be linear or contain rings...
alcohol
Alcohol
In chemistry, an alcohol is an organic compound in which the hydroxy functional group is bound to a carbon atom. In particular, this carbon center should be saturated, having single bonds to three other atoms....
that has been isolated from a variety of sources such as cajuput oil
Cajuput oil
Cajeput oil is a volatile oil obtained by distillation from the leaves of the myrtaceous tree Melaleuca leucadendra, and probably other Melaleuca species. The trees yielding the oil are found throughout the Malay archipelago, the Malay Peninsula and over the hotter parts of the Australian...
, pine oil
Pine oil
Pine oil is an essential oil obtained by the steam distillation of needles, twigs and cones from a variety of species of pine, particularly Pinus sylvestris....
, and petitgrain
Petitgrain
Petitgrain is an essential oil that is extracted from the green twigs of the bitter orange plant via steam distillation.-Production:...
oil. There are three isomer
Isomer
In chemistry, isomers are compounds with the same molecular formula but different structural formulas. Isomers do not necessarily share similar properties, unless they also have the same functional groups. There are many different classes of isomers, like stereoisomers, enantiomers, geometrical...
s, alpha-, beta-, and gamma-terpineol, the last two differing only by the location of the double bond
Double bond
A double bond in chemistry is a chemical bond between two chemical elements involving four bonding electrons instead of the usual two. The most common double bond, that between two carbon atoms, can be found in alkenes. Many types of double bonds between two different elements exist, for example in...
. Terpineol is usually a mixture of these isomers with alpha-terpineol as the major constituent.
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
Lapsang souchong
Lapsang souchong is a black tea originally from the Wuyi region of the Chinese province of Fujian. It is sometimes referred to as smoked tea...
tea; the α-terpineol originates in the pine smoke used to dry the tea.
Although it is naturally occurring, terpineol is commonly manufactured from the more readily available alpha-pinene
Alpha-Pinene
α-Pinene is an organic compound of the terpene class, one of two isomers of pinene. It is an alkene and it contains a reactive four-membered ring. It is found in the oils of many species of many coniferous trees, notably the pine. It is also found in the essential oil of rosemary...
.
In one study, an alternative route starting from d-limonene
Limonene
Limonene is a colourless liquid hydrocarbon classified as a cyclic terpene. The more common D isomer possesses a strong smell of oranges. It is used in chemical synthesis as a precursor to carvone and as a renewably-based solvent in cleaning products....
was demonstrated:
Limonene is reacted with trifluoroacetic acid
Trifluoroacetic acid
Trifluoroacetic acid is the simplest stable perfluorinated carboxylic acid chemical compound, with the formula CF3CO2H. It is a strong carboxylic acid due to the influence of the electronegative trifluoromethyl group. TFA is almost 100,000-fold more acidic than acetic acid...
in a Markovnikov addition
Markovnikov's rule
In organic chemistry, Markovnikov's rule or Markownikoff's rule is an observation based on Zaitsev's rule. It was formulated by the Russian chemist Vladimir Vasilevich Markovnikov in 1870....
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.
External links
- MSDS for alpha-terpineol
- http://commons.wikimedia.org/wiki/Gallery_Terpenes