5. Turpentine
Synonyms Gum turpentine; Gum thus.
Biological Source Turpentine is the oleoresin obtained from pinus palustris Miller and from other species of Pinus, belonging to the natural order Pinaceae.
Preparation Turpentine is usually collected from the slash pine i.e., Pinus elliottii Engelmann var. eliotti, and Pinus palustris Miller, which grow in abundance in the Northern Florida, Georgia, and North and South Carolina. However, the yield of turpentine exclusively depends on the treatment and the size of the tree. If proper skill and expertise are practiced the pine trees may yield turpentine for 15 to 20 years at a stretch.
The oleoresin is normally secreted in the ducts that are situated almost beneath the cambium in the sapwood. In spring the bark is neatly cut from the tree with the help of a long-handled cutting knife known as the “bark-hack”. After the removal of the chipped bark, the freshly exposed surface is quickly sprayed with a solution of 50% (w/w) sulphuric acid.* The flowing oleoresin is guided by galvanized metal gutters right into the various containers tied close to the tree-trunk. The thickliquid thus collected is removed as turpentine by pot-still distillation periodically.
Characteristic Features The gum turpentine is an yellowish, opaque, sticky mass having a characteristic odour and taste. It is almost insoluble in water, but soluble in ether, ethanol, chloroform and glacial acetic acid.
Chemical Constituents The gum-turpentine when subjected to steam-distillation yields 15 to 30% of a volatile oil known in the trade as “turpentine oil”. It contains mainly the terpenes, such as: dextro- and laevo-α-pinene, β-pinene and camphene.
Uses
1. It is employed externally as a counterirritant.
2. It is also used as a rubefacient.
3. It is used as a constituent of stimulating ointments.
4. It is employed industrially as an insecticide.
5. It is used as a solvent for waxes.
6. It is utilized extensively in the production of synthetic comphor.
7. It is used in making various types of polishes, such as: shoe polish, furniture polish and stove polish.
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* Acid treatment collapses the thin-walled parenchymal cells which line the resin ducts. Thus, the duct channels get enlarged thereby allowing a faster uninterrupted flow of oleoresin and minimising the chances of hardened secretions blocking the outlets.
