Conifer resin, rosin acids from

More than 200 diterpenes with an abietane skeleton are reported to exist naturally Numerous representatives oeeur in conifers. Selected examples include palustra-diene, also referred to as (-)-8,13-abietadiene, from the pine tree Pintds palustris, from the so-called berries of the sade tree Juniperus sabina (Cupressaceae) and other species of juniper trees, (-)-abietenol from the pine Pinus silvestris and the fir Abies sibirica, (-)-abietic aeid belonging to the resin acids of turpentine and wide-spread in conifers such as various pines Pinus), larch trees Larix) and firs Abies), as well as (+)-palustric acid from the balm and the roots of Pinus palustris, isolated from gum rosin. 

Diterpenes usually are components of plant resins and sometimes are encountered as by-products from the isolation of essential oils (e.g., rosin or naval stores from turpentine production). The most commonly encountered diterpenes are nonvolatile acids from conifers and legumes (Croteau and Johnson, 1985 Langenheim, 1990). 

Solvent drying of conifer woods with water-miscible solvents such as acetone, however, remains economically unfavorable because of solvent losses and energy requirements. A limited quantity of perfumery-grade pine needle oil can be obtained from a few Pinus species, but the needle oils from most species too closely resemble turpentines to command the premium prices that would justify the production costs. Although the rosins that could be derived from needles of many pines are essentially similar to the xylem rosins, the needle rosins from other species are of unusual composition. Such rosins could be the source of specialty fine chemicals but would not have any significant impact on rosin as a commodity material. The composition of the resin acids in pine needles may be an important characteristic in chemoteixonomic and genetic studies (18). 

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