Pinene


Pinene is a bicyclic monoterpene chemical compound. There are two structural isomers of pinene found in nature: α-pinene and β-pinene. As the name suggests, both forms are important constituents of pine resin; they are also found in the resins of many other conifers, as well as in non-coniferous plants such as camphorweed and big sagebrush. Both isomers are used by many insects in their chemical communication system. The two isomers of pinene constitute the major component of turpentine.

Isomers


skeletal formula
perspective view
X
X
ball-and-stick model
X
X
name
--α-pinene
--α-pinene
--β-pinene
--β-pinene
CAS number
7785-70-8
7785-26-4
19902-08-0
18172-67-3

Biosynthesis

α-Pinene and β-pinene are both produced from geranyl pyrophosphate, via cyclisation of linaloyl pyrophosphate followed by loss of a proton from the carbocation equivalent. Researchers at the Georgia Institute of Technology and the Joint BioEnergy Institute have been able to synthetically produce pinene with a bacterium.

Plants

is the most widely encountered terpenoid in nature and is highly repellant to insects.
Alpha-pinene appears in conifers and numerous other plants. Pinene is a major component of the essential oils of Sideritis spp. and
Salvia spp.. Cannabis also contains alpha-pinene and beta-pinene. Resin from Pistacia terebinthus is rich in pinene. Pine nuts produced by pine trees contain pinene.
Makrut lime fruit peel contains an essential oil comparable to lime fruit peel oil; its main components are limonene and β-pinene.
The racemic mixture of the two forms of pinene is found in some oils like eucalyptus oil.

Usage

In chemical industry, selective oxidation of pinene with some catalysts gives many compounds for perfumery, such as artificial odorants. An important oxidation product is verbenone, along with pinene oxide, verbenol, and verbenyl hydroperoxide.
Pinenes are the primary constituents of turpentine.
The use of pinene as a biofuel in spark ignition engines has been explored. Pinene dimers have been shown to have heating values comparable to the jet fuel JP-10.