Pine tall oil

The neutral or unsaponifiable materials present in tall oil include anhydrides, pheno-lics, diterpene aldehydes and alcohols, stil-benes, and steroids. In the neutral fraction of southern pine tall oil soap, 80 compounds have been identified. They include 25.1 percent sistosterol and a total of 32.4 percent steroids. The sistosterol content of crude tall oil is 2-3 percent and is the main component of the neutral fraction. 

Production. Rosin is isolated from pine trees, principally from longleaf Pinuspalustris slash Pinus ellioti and lobloUy pine Pinus taeda. The products are known as gum, wood, or tall oil rosin, based on the method of isolation and the source. 

Wood is the raw material of the naval stores iadustry (77). Naval stores, so named because of their importance to the wooden ships of past centuries, consist of rosin (diterpene resin acids), turpentine (monoterpene hydrocarbons), and associated chemicals derived from pine (see Terpenoids). These were obtained by wounding the tree to yield pine gum, but the high labor costs have substantially reduced this production in the United States. Another source of rosin and turpentine is through extraction of old pine stumps, but this is a nonrenewable resource and this iadustry is in decline. The most important source of naval stores is spent sulfate pulpiag Hquors from kraft pulpiag of pine. In 1995, U.S. production of rosin from all sources was estimated at under 300,000 metric tons and of turpentine at 70,000 metric tons. Distillation of tall oil provides, in addition to rosin, nearly 128,000 metric tons of tall oil fatty acids annually (78). 

A rather impressive Hst of materials and products are made from renewable resources. For example, per capita consumption of wood is twice that of all metals combined. The ceUulosic fibers, rayon and cellulose acetate, are among the oldest and stiU relatively popular textile fibers and plastics. Soy and other oilseeds, including the cereals, are refined into important commodities such as starch, protein, oil, and their derivatives. The naval stores, turpentine, pine oil, and resin, are stiU important although their sources are changing from the traditional gum and pine stumps to tall oil recovered from pulping. 

The resin acids found in rosins are generally of the abietic- and pimaric-type. Rosins of various pine species differ in their content of abietic vs. pimaric-type acids. Rosins from species exhibiting high abietic-type acid compositions are preferred for production of rosin derivatives. However, the differences in properties of rosins are often associated with their non-resin acid content instead of their chemical compositions. On the other hand, the compositions of rosins from different sources greatly differ [22]. Table 8 shows a typical distribution of resin acids in rosins obtained from gum, tall oil and wood sources. 

Some useful by-products of pulping are derived from these extractives, the most important of which are turpentine and tall oil. Turpentine is a mixture of bicyclic hydrocarbons with the empirical formula C10H16, the dominant components of which are a- and /J-pinene (Figure 2.8). They are produced as volatile by-products at a yield of around 4-5 litres per tonne of wood (for pine) and are used as a solvent and as a chemical feedstock. 

Sources 1 D.H. Bennett, C.M. Falter and A.F. Campbell, Prediction of Effluent Characteristics, Use of Lime Treatments and Toxicity of the Proposed Ponderay Mill , Appendix in engineer s report on Effluent Characteristics for Washington State Department of Ecology, 1987. 2 D.F. Zinkel, Tall Oil Precursors of Loblolly Pine , Tappi, 1975, 58, 2, pp. 118-121. 3 R.W. Hemingway, P.J. Nelson and W.E. Hillis, Rapid Oxidation of the Fats and Resins in Pinus Radiata Chips for Pitch Control , Tappi, 1971, 54, 1, pp. 95-98. 4 D.O. Foster, D.F. Zinkel and A.H. Conner, Tall Oil Precursors of Douglas Fir , Tappi, 1980, 63, 12, pp. 103-105. 

In Chemical Manufacturing there is a subsector entitled Gum and Wood Chemicals (NAICS 3251911) that covers many of the miscellaneous chemicals that we have discussed here, including charcoal, tall oil, rosin, turpentine, and pine oil. The value of shipments is 960 million. The pulp... 

There are several materials that make up this category, including wood-derived tall oil rosins and pine stump extracts sold under the well known VinsoH trade mark. They consist of complicated mixtures containing greater or lesser amounts of abietic acid (Fig 3.2) together with pimaric acid, and phenolic compounds such as phlobaphenes. 

Tall oil is a byproduct obtained from the manufacture of paper pulp from pine trees. It is separated by vacuum distillation (50 mm Hg) in the presence of steam into four primary products. In the order of decreasing volatility these are unsaponifiables (US), fatty acid (FA), rosin acids (RA), and pitch (P). Heat exchangers and rcboilers are heated with Dowtherm condensing vapors. Some coolers operate with water and others generate steam. Live steam is charged to the inlet of every reboiler along with the process material. Trays are numbered from the bottom of each tower. 

The oleoresinous exudate or "pitch of many conifers, but mainly pines, is the raw material for the major products of the naval stores industry. The oleoresin is produced in the epithelial cells which surround the resin canals. When the tree is wounded the resin canals are cut. The pressure of the epithelial cells forces die oleoresin to the surface of die wound where it is collected. The oleoresin is separated into two fractions by steam distillation. The volatile fraction is called gum turpentine and contains chiefly a mixture of monoterpenes but a smaller amount of sesquiterpenes is present also. The nonvolatile gum rosin 5 consists mainly of llie dilerpenuid resin acids and smaller amounts of esters, alcohols and steroids. Wood turpentine, wood rosin and a fraction of intermediate volatility, pine oil are obtained together by gasoline extrachon of the chipped wood of old pine stumps. Pine oil is largely a mixture of the monoterpenoids terpineol. borneol and fenchyl alcohol. Sulfate turpentine and its nonvolatile counterpart, tall oil, 5 are isolated as by-products of the kraft pulping process. Tall oil consists of nearly equal amounts of saponified fatty acid esters and resin acids. 

Several companies, in cooperation with the U.S. Forest Service, have been studying the effectiveness of paraquat in enhancing the quantity of chemicals produced in slash and loblolly pine trees. Results over the last 6 years show that there can be a positive effect and that beta-pinene is preferentially produced in slash pines by treatment with paraquat. Results reported on loblolly pine show an increase of 50% in tall oil content when correctly applied. The expected increase... 

Turpentine and Rosin The major naval stores products are turpentine, primarily composed of volatile terpenes, and rosin, mainly a mixture of resin acids. Principally the same products, but in different proportions, can be recovered by tapping resin-rich trees or by steam distillation or solvent extraction of wood residues and especially stumps. Today, however, the most important source for turpentine and rosin is the tall oil recovered after pulping of pine wood (see Section 10.3.1). 

The name "tall oil" originates from the Swedish word "tall" which means pine. 

In Scandinavia where Scots pine is the principal wood material in the kraft pulp industry, a normal yield of tall oil in the northern regions is at least 50 kg/ton of pulp but it is considerably lower in the middle or southern regions. In the United States, southern pines also give a tall oil yield of about 50 kg/ton of pulp whereas only about 30 kg/ton can be recovered from Douglas fir in the industry at the Pacific coast. 

The spent black liquor from the kraft pulping of pines contains the less volatile products of the wood resin in the form of sodium salts or soaps. The liquor first is concentrated in multiple-effect evaporators, and then the concentrate is sent to settling tanks. The soaps rise to the surface, are skimmed off, and then are acidified with sulfurous or sulfuric acid. The crude tall oil rises to the top and is mechanically separated. Crude tall oil from southern pines contains 40-60 percent resin acids and 40-55 percent fatty acids with 5-10 percent neutral substances. These components are separated by fractional distillation under vacuum. 

One metric ton of crude tall oil yields about 350 kg of rosin, 300 kg of fatty acids, and 300 kg of head and pitch fractions. For each metric ton of pulp produced, northern pines yield about 50 kg of tall oil, and the southern pines yield about 125 kg. The U.S. capacity for fractional distillation of tall oil is nearly one million metric tons per year. 

Fatty Acids. Of the total fatty acids produced annually in the United States, amounting to more than 450,000 tons, 35 percent come from tall oil. The solvent extraction of pine wood yields only 1 percent fatty acids and their esters. The yield is not increased, however, by paraquat (dipyridyl herbicides) treatment. Hence, the kraft-pulping industry will continue to be the major source of fatty acids from wood. The approximate distribution of uses of the fatty acids are ... 

Pine-Based Chemicals Crude Tall Oil Fractionation... 

There are three kinds at present. One is called gum rosin, which is obtained as the residue of the distillation of turpentine oil from pine resin, which is collected from pine woods. The second is called "wood rosin", which is obtained by extraction from chips of old pine stamps using a solvent. The third is the "tall oil rosin", which is obtained from the digester waste in the manufacture of kraft pulp. Rosin is produced in large amounts in America, Russia and China. At present wood rosin is mostly produced, and the tall oil rosin will gradually increase, but the production of gum rosin is decreasing. The most popular use of rosin is as size in paper production. 

---