Terpenes, trees

Chemical iajections iato piae trees have been reported to have stimulatory effects on the natural production of resias and terpenes and may result ia high yields of these valuable chemicals. Combiaed oleoresin—timber production ia mixed stands of piae and timber trees is under development, and it appears that when short-rotation forestry is used, the yields of energy products and timber can be substantially higher than the yields from separate operations. 

Gum Elemi. This resin, tapped from trees in the Philippines, contains a higher concentration of essential oils than other natural resins. It is a soft, sticky, plastic material that can be deformed manually. Gum elemi [9000-75-3] contains 20—25% essential oils, 13—19% acids, 30—35% resenes (condensed decarboxylated resin acids), and 20—25% terpenic resinols (condensed terpene alcohols). It has an acid number of 20—35 and a saponification number of 20—40. Gum elemi is a film-forming plasticizing resin used in lacquers. 

Trees, especially conifers, contain tall oils. Tall oil is not isolated dkecfly tall oil fatty acids are isolated from the soaps generated as a by-product of the sulfate pulping process for making paper. Refined tall oil fatty acids are obtained by acidification of the soaps, followed by fractional distillation to separate the fatty acids from the rosin acids and terpene hydrocarbons that also are present in the cmde tall oil fatty acids (see Carboxylic acids Fatty ACIDS FROMTALL OIL). 

Camphor [126-04-5] (11), menthol [89-78-1] (12), and thymol [89-83-8] (13) ate used in topical over-the-counter cough and cold preparations. Camphor is isolated from the camphor tree, Cinnomomum camphora T. Nees Eherneier, or prepared synthetically from a-pinene or isobomeol. About 75% of the camphor sold in the United States is synthetic. Menthol, commercially the most important terpene alcohol, is obtained by crysta11i2ation from... 

The other class of acrylic compatible tackifiers includes those based on ter-penes. Terpenes are monomers obtained by wood extraction or directly from pine tree sap. To make the polyterpene tackifiers, the monomers have to be polymerized under cationic conditions, typically with Lewis acid catalysis. To adjust properties such as solubility parameter and softening point, other materials such as styrene, phenol, limonene (derived from citrus peels), and others may be copolymerized with the terpenes. 

I.4. Polyterpene resins. Terpene resins are obtained from natural terpene monomers obtained from naval stores, paper pulp production, and citrus juice production. Terpenes are found in almost all living plants, and the turpentine oil from pine trees is the most important source. 

Gum turpentine is obtained from wounding living trees to get an exudate containing turpentine and rosin. Turpentine is separated from the rosin by continuous steam distillation and further fractionation. Wood turpentine comes from the extraction of stumps of pine trees using naphtha, and subsequent separation of rosin and turpentine by fractional distillation. Tail-oil turpentine is a byproduct of the Kraft sulphate paper manufacture. Terpenes are isolated from the sulphate terpentine and separated from the black digestion liquor. The composition of turpentine oils depends on its source, although a-pinene and p-pinene are the major components. 

Polyterpenes. Polyterpenes is one of the first classes of non-polar tack-ifiers to be developed. Terpene monomers are a by-product in the extraction of rosin from wood stumps or tree sap, and from the extraction of oils from citrus fruits. The latter is the dominant source. As such, polyterpene prices generally mirror those of citrus fruits, which fluctuate substantially from one growing season to the next. Terpenes like rosin are cyclic, see Fig. 6, which is partly responsible for their excellent solvent properties. 

It is the determination of volatile organic compounds produced from natural products that requires separation techniques that allow isolation of stereoisomers. The most commonly determined groups are the terpene and sesquiterpene species present in essential oils, which are used as key indicators of biological factors such as the growth season, geographic location, climate, etc. These species are also released directly into the atmosphere by very many plants and trees, and make a substantial contribution to global biogeochemical cycles. 

The first type is representative of those eucalyptus trees whose oils contain the terpene pinene in marked quantity, cineol either not at all or only in small amount, and from which phellandrene is absent. 

The wonderful fragrance of leaves from the California bay tree is due primarily to myrcene, a simple terpene. 

Trees and shrubs contain a group of fragrant compounds called terpenes. The simplest terpene is isoprene. All other terpenes are built around carbon skeletons constructed from one or more isoprene units. Plants emit terpenes into the atmosphere, as anyone who has walked in a pine or eucalyptus forest will have noticed. The possible effect of terpenes on the concentration of ozone in the troposphere has been the subject of much debate and has led to careful measurements of rates of reaction with ozone. 

No geographic structure was revealed by this analysis, with trees from Arch Cape, Oregon, Whitetish, Montana, and sites from northern British Columbia, including Queen Charlotte Islands, being closely associated. The authors remarked on the lack of differentiation between coastal and interior populations. A reinvestigation of red cedar from 55 sites (3-6 trees per site) provided a new data set that was analyzed by numerical and discriminant-function analyses (von Rudloff et al., 1988). These analyses confirmed the low intra- and interpopulational variation seen in the earlier study, but did reveal small differences between coastal and interior populations. No correlations between northern and southern populations emerged from the analyses likewise, elevation had no effect on terpene composition. 

The value of spruce-oil chemistry in sorting out problems of hybridization and introgression—major factors in Picea taxonomy—was succinctly summarized by von Rudloff who defined three situations (1) Terpene variation is limited such that it is not possible to use these characters in studies of introgression this is the case in eastern North America where the ranges of black spruce and red spruce overlap. (2) Sufficient variation in terpene profiles exists for the compounds to be useful markers in systematic studies as seen in white spruce. Brewer s spruce, and Sitka spruce. (3) Tree-to-tree variation in terpene content is so variable that use in che-mosystematic studies is precluded, or at least requires very large sample sizes for statistical reliability, as seen with Engelmann s spruce. 

Baradat, P., Michelozzi, R., Tognetti, M. L. and Khaldi, A. 1995. Geographical variation in the terpene composition of Pinus halepensis Mhl. Pages 141-158 in P. Baradat, W. T. Adams, and G. Miiller-Stark (eds.) Population Genetics and Genetic Conservation of Forest Trees, SPB Academic Press, Amsterdam. 

Whereas some species oxidize host terpenes more randomly, producing an array of rather unspecific volatiles with little information, others use highly selective enzyme systems for the production of unique olfactory signals. However, apart from transformations of monoterpene hydrocarbons of host trees, oxygenated monoterpenes may well be biosynthesized de novo by the beetles (see below). 

Oxygenated monoterpenes which are found in almost every bark beetle species attacking coniferous trees, include czs-verbenol 246, frans-verbenol 247, and myrtenol 248, representing primary products of allylic oxidation of the host terpene a-pinene 45. Further oxidation of 247 or 248 leads to the... 

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