Tall oil
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Tall oil, also called liquid rosin or tallol, is a viscous yellow-black odorous liquid obtained as a byproduct of the Kraft process of wood pulp manufacture. The name originated as anglicization of Swedish "tallolja" ("pine oil").
Crude tall oil contains rosins, unsaponifiable sterols (5-10%), resin acids (mainly abietic acid and its isomers), fatty acids (mainly palmitic acid, oleic acid and linoleic acid), fatty alcohols, some sterols, and other alkyl hydrocarbon derivates. By fractional distillation tall oil rosin is obtained, with rosin content reduced to 10-35%. By further reduction of the rosin content to 1-10%, tall oil fatty acid (TOFA) can be obtained, which is cheap, consists mostly of oleic acid, and is a source of volatile fatty acids. The rosin finds use as a component of adhesives, rubbers, and inks, and as an emulsifier. The pitch is used as a binder in cement, an adhesive, and an emulsifier for asphalt.
TOFA is a low-cost alternative to tallow fatty acids for production of soaps and lubricants. When esterified with pentaerythritol, it is used as a compound of adhesives and oil-based varnishes.
Tall oil is also used in oil drills as a component of drilling fluids.