Turpentine

Turpentine (which is also called spirit of turpentine, oil of turpentine, terebenthine, terebenthene, terebinthine and, colloquially, turps) is a fluid obtainable by the distillation of resin harvested from living trees, mainly pines. Principally used as a specialized solvent, it is also a source of material for organic syntheses.

Turpentine is composed of terpenes, primarily the monoterpenes α-pinene and β-pinene, with lesser amounts of carene, camphene, limonene, and terpinolene. Nowadays, turpentine is rarely the product of distillation of pine resin, but is a byproduct of pulping. Pulping is achieved by two processes, the Kraft process and the sulfite process. The turpentines obtained from these two processes differ in their chemical compositions. The sulfite process gives a product that is rich in cymene, whereas the Kraft process gives a pinene-rich product.

Substitutes include white spirit or other petroleum distillates, although the constituent chemicals are very different.

The word turpentine derives (via French and Latin) from the Greek word τερεβινθίνη, terebinthine in English, in turn the feminine form (to conform to the feminine gender of the Greek word, which means 'resin') of an adjective (τερεβίνθινος) derived from the Greek noun τερέβινθος for the terebinth tree.

Although the word originally referred to the resinous exudate of terebinth trees (e.g. Chios turpentine, Cyprus turpentine, and Persian turpentine), it now refers to that of coniferous trees, namely crude turpentine (e.g. Venice turpentine is the oleoresin of larch), or the volatile oil part thereof, namely oil (spirit) of turpentine; the latter usage is much more common today.

Important pines for turpentine production include maritime pine (Pinus pinaster), Aleppo pine (Pinus halepensis), Masson's pine (Pinus massoniana), Sumatran pine (Pinus merkusii), longleaf pine (Pinus palustris), loblolly pine (Pinus taeda), slash pine (Pinus elliottii), and ponderosa pine (Pinus ponderosa).

Crude turpentine collected from the trees may be evaporated by steam distillation in a copper still. Molten rosin remains in the still bottoms after turpentine has been distilled out. Such turpentine is called gum turpentine. The term gum turpentine may also refer to crude turpentine, which may cause some confusion.

Turpentine may alternatively be extracted from destructive distillation of pine wood, such as shredded pine stumps, roots, and slash, using the light end of the heavy naphtha fraction (boiling between 90 and 115 °C or 195 and 240 °F) from a crude-oil refinery. Such turpentine is called wood turpentine. Multi-stage counter-current extraction is commonly used so that fresh naphtha first contacts wood leached in previous stages and naphtha laden with turpentine from previous stages contacts fresh wood before vacuum distillation to recover naphtha from the turpentine. Leached wood is steamed for additional naphtha recovery prior to burning for energy recovery.