Terpineol is a naturally occurring
monoterpeneMonoterpenes are a class of terpenes that consist of two isoprene units and have the molecular formula C10H16. Monoterpenes may be linear or contain rings...
alcoholIn 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 oilCajeput 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 oilPine 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
petitgrainPetitgrain is an essential oil that is extracted from the green twigs of the bitter orange plant via steam distillation.-Production:...
oil. There are three
isomerIn 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 bondA 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 souchongLapsang 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-pineneα-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-limoneneLimonene 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 acidTrifluoroacetic 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 additionIn 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.
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