Turpentine is a volatile liquid derived from the resinous exudate of certain trees, primarily those belonging to the Pinus genus. It is a complex mixture of organic compounds, historically used as a foundational raw material in early industrial chemistry. Today, turpentine remains a notable commercial product, recognized for its strong solvent capabilities.
Natural Origin and Extraction
The source material for commercial turpentine is oleoresin, a sticky substance naturally produced by coniferous trees, most often various species of pine. Historically, the liquid was obtained by tapping a living tree, similar to maple syrup production. V-shaped incisions were cut into the bark, allowing the resin to flow into collecting cups.
This crude oleoresin is processed through steam distillation to separate the components. The volatile fraction that vaporizes and is condensed is known as gum turpentine, while the non-volatile solid residue left behind is rosin. Another major source today is sulfate turpentine, a byproduct recovered during the Kraft process of wood pulping.
Key Chemical Components
Turpentine is defined by its composition as a mixture of hydrocarbons known as terpenes. It is dominated by monoterpenes, which are organic compounds with the chemical formula C10H16. These molecules are classified as volatile organic compounds (VOCs), which accounts for the liquid’s low boiling point and rapid evaporation.
The two most abundant components are alpha-pinene and beta-pinene, which together can constitute over 90% of a high-quality sample. Alpha-pinene is typically the most prevalent, often making up 60% to 80% of the total composition, and gives turpentine its characteristic pine-like aroma. Other terpenes found in smaller amounts include camphene, limonene, and 3-carene, with the exact ratios varying based on the source tree species and the extraction method used.
Historical and Modern Applications
Turpentine has a long history of use, stretching back to ancient civilizations that utilized pine resin for medicinal purposes. In folk medicine, it was applied topically to treat wounds. Early artists also relied on the liquid as the traditional solvent for thinning oil-based paints and cleaning brushes.
Today, its primary purpose is industrial, where it remains a powerful solvent and paint thinner for varnishes and oil-based coatings. Beyond direct solvent use, it is a feedstock for synthesizing other valuable chemicals. Turpentine’s components, particularly the pinenes, are processed to create synthetic camphor and aromatic compounds used in fragrances, flavors, and cleaning products.
Safety Profile and Toxicity
Despite its natural origin, turpentine is a hazardous substance that requires careful handling. Ingestion is particularly dangerous because the liquid is an aspiration hazard; if swallowed, it can easily enter the lungs and cause severe irritation, known as chemical pneumonitis. Ingestion can also lead to gastrointestinal distress and systemic effects, including damage to the central nervous system and kidneys.
Inhalation of its vapors can cause immediate irritation to the eyes, nose, throat, and respiratory tract, potentially leading to headaches or dizziness. Repeated skin contact may result in localized irritation, redness, and allergic contact dermatitis. Safe storage requires keeping the liquid in a well-ventilated area away from heat sources and ignition to mitigate flammability and vapor hazards.