Stump

Natural resins were probably known to early people, who recognized them as exudates from trees. Collection and use of these resins have been recorded by early Roman and Greek historians. Many products have been collected by the same methods throughout history to the present time. However, increased labor costs and competition from synthetic resins have reduced the demand for some natural resins, so they have become less available. In other cases, such as that of rosin, the traditional collection of gum from trees has been supplemented or replaced by isolation from other sources, such as paper pulping and tree stumps. 

In the wood rosin process, rosin is isolated from aged pine stumps that have been left in fields cleared for farming or lumbering operations. The stumps are cut and shredded to pieces the size of matchsticks. The wood chips are then extracted with an appropriate solvent, eg, aUphatic or aromatic petroleum hydrocarbons or ketones. The extract is fractionally separated into nonvolatile cmde rosin, volatile extractibles, and recovered solvent. The dark rosin is usually refined further to lighter-colored products using selective solvents or absorption. 

Ammonium sulfamate is highly effective in nonselective herbicides to control weeds, bmsh, stumps, and trees (58) (see Herbicides). 

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. 

Rosin and tall oil-based tackifiers are derived from feedstock, which is typically obtained by extraction and distillation of the materials from shredded tree stumps or wood chips. A typical structure of one of the different products obtained through this process is this abietic acid structure shown in Fig. 14 as a representative of the rosin acid family. 

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. 

Klotz, m, block, log, stump, -artikel, m, (Calico) padded style, -bad, n, slop-pad liquor, padding liquor, -druck, m. slop-pad printing, klotzen, v.t. (Calico) slop-pad, pad,... 

Stock, n. stick, staff stock rod, pole block trunk, butt, stump main part, body story, floor (of a building) mold (SricA ) clamp (Brewing, etc.) vat, back, stock-, utterly, entirely. -bHnd, a. stone-blind, stocken, v.i. stop, slacken, stagnate curdle ... 

Strunk, m. stump, trunk, stalk, stock, stem, struppig, a. bristly, shaggy, rough. 

Stumpf, OT. stump stub ((jeom.) frustum, stum -eckig, a. blunt-comered. -kantig, a. 

Wischer, m. wiper rubber, duster, swab, sponge, (drawing) stump. 

According to U.S. Patent 3,002,891, the following describes pilot plant production of bromelain. Stripped pineapple stumps were passed four times through a three roll sugar mill press. 

As you study organic chemistry, take the time to work the problems. Do the ones you can, and ask for help on the ones you can t. If you re stumped by a particular problem, check the accompanying Study Guide and Solutions Manual for an explanation that will help clarify the difficulty. Working problems takes effort, but the payoff in knowledge and understanding is immense. 

Galison, Peter, Stump, David, (eds.), The Disunity of Science. Stanford University Press Stanford, California, 1996. 

Responding to a comment about die weight of the tree-stump stools in die lounge, Mr. Hunter explained that they were cut down and polished from a butternut tree in Mr. Wilson s father s backyard in Massachusetts. I pushed on mine heavily to face die bar and give my neighbors more privacy. 

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