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.
Etymology 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.
Source trees
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).
Converting crude turpentine to oil of turpentine
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.
Sulfate turpentine When producing chemical wood pulp from pines or other coniferous trees, sulfate turpentine may be condensed from the gas generated in kraft process pulp digesters. The average yield of crude sulfate turpentine is 5–10 kg/t pulp. Unless burned at the mill for energy production, sulfate turpentine may require additional treatment measures to remove traces of sulfur compounds.
Uses
Solvent As a solvent, turpentine is used for thinning oil-based paints, for producing varnishes, and as a raw material for the chemical industry. Its use as a solvent in industrialized nations has largely been replaced by the much cheaper turpentine substitutes obtained from petroleum such as white spirit. A solution of turpentine and beeswax or carnauba wax has long been used as a furniture wax.
Lighting Spirits of turpentine, called camphine, were burned in lamps with glass chimneys in the 1830s through the 1860s. It produced a bright light but had a strong odour. Turpentine was also blended with grain alcohol to create burning fluid. Both were used as domestic lamp fuels, replacing whale oil as the dominant lamp fuel until the advent of kerosene, gas lighting, and electric lights.
Source of organic compounds Turpentine is also used as a source of raw materials in the synthesis of fragrant chemical compounds. Commercially used camphor, linalool, alpha-terpineol, and geraniol are all usually produced from alpha-pinene and beta-pinene, which are two of the chief chemical components of turpentine. These pinenes are separated and purified by distillation. The mixture of diterpenes and triterpenes that is left as residue after turpentine distillation is sold as rosin.
Niche uses Because it is naturally a pine pitch thinner, it will remove pitch from clothing while other common solvents may not do as well. Turpentine is also added to many cleaning and sanitary products due to its antiseptic properties and its "clean scent". Honda motorcycles, first manufactured in 1946, ran on a blend of gasoline and turpentine, due to the scarcity of gasoline in Japan following World War II. The French Emeraude rocket uses a similar fuel mixture. Turpentine has also been researched as a potential biofuel for mixing into gasoline. In his book If Only They Could Talk, veterinarian and author James Herriot describes the use of the reaction of turpentine with resublimed iodine to "drive the iodine into the tissue", or perhaps just impress the watching customer with a spectacular treatment (a dense cloud of purple smoke).
Safety and health considerations
… excerpt ends here. Continue reading the full article.
