Sulfate Kraft Naval Stores

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). 

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. 

Increases in yield of naval stores are brought about by chemical treatment of the exposed wood, especially with paraquat herbicides (dipyridyl compounds). This treatment stimulates extensive oleoresin formation and diffusion into the wood, extending to the pith of the tree and several feet above the treatment level. As much as 40 percent oleoresin content in the wood has been produced. Such treatment could double naval stores production, for both gum and sulfate processes. It also has the potential of providing a new type of wood naval stores by solvent extraction prior to kraft pulping, or a combination of both methods. 

Turpentine and rosin are also produced by solvent extraction of heartwood chips of pine stumps, which are by-products of the lumber industry, and as by-products of the paper (sulfate or kraft pulping) industry. The last source is reported to account for the largest volumes of turpentine and rosin produced in the United States. These products derived from pines and other resinous conifers are commonly called naval stores. 

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