American rosin

Molnar, E. J. Skinner, E. W. (1942). A study of zinc oxide-rosin cements. I. Some variables which affect hardening time. Journal of the American Dental Association, 29, 744-51. 

The German example was followed by the French and British and later by the Americans A 2Q lb bomb developed by the French was called Chenard" and was considered to be successful. It contained a mixture of rosin and celluloid as the principal incendiary material. 

The tissues of wood, bark, and the leaves of trees contain a great variety of chemical substances of considerable scientific interest and some of practical value. Turpentine, pine oil, and rosin from the resins of pines are the most important commercial extractives from American woods. 

There are a few minor wood-based chemical industries. After chestnut blight wiped out the American chestnut, U.S. tannin production essentially ceased. The main natural tannins, watde and quebracho, are now imported. High U.S. labor costs and the advent of synthetic tannins make re-establishment of a U.S. tannin industry unlikely. Tannins are used in oil-weU drilling muds. Tree exudates are a continuing wood-based chemical industry. Tree exudates include mbber, tme carbohydrate gums (eg, acacia gum), kinos (eg, the phenolic exudates from eucalyptus), balsams (eg, Storax from l iquidambar spp.), and many different types of oleoresins (mixtures of a soHd resin and a liquid essential oil). The most important oleoresin stiU collected in the United States is pine gum (rosin plus turpentine). 

Figure 16.57. Positions of tryptophan probes in the lactate dehydrogenase subunit from B. stearothermophilus. The badcbone of the protein is shown as a ribbon, and the positions of each single change of rosine to tryptophan are indicated by the residue number. Reprinted, permission, from Ref. I25, Copyright O t9l9t. American Chemical Socie. ...

Isolated from American colophony, (rosin). Plates. M.p. 170-4°. [a]n — 102° in EtOH. Sol. MeOH, EtOH, Et,0, AcOH, Me CO, CHClj, CfHg. Insol. HgO. Forms additive compound with maleic anhydride. Dehydrogenation with selenium —>> retene. Absorption maximum at 237-5 mu. 

Tall oil fatty acids n. Class of products generally containing 90% or more fatty acid obtained by ffactionization of crude tall oil The fatty acids are a mixture of oleic and linoleic acids with lesser amounts of saturated and other unsaturated fatty acids. The remainder consists of rosin and neutral materials. Paint pigment, drying oils, polymers, resins, naval stores, cellulo-sics esters, and ink vehicles, vol 3. American Society for Testing and Material, 2001. 

Colophony (rosin) is a resin obtained from different species of coniferous trees. There are three types of colophony, depending on the method of recovery gum rosin, wood rosin and tail-oil rosin. Gum rosin is obtained from various species of living pine trees. The trees are tapped for oleoresin, which is then distilled to obtain turpentine as the distillate and gum rosin as the distillation residue. Wood rosin is produced from old pine stumps. Tail-oil rosin is obtained as a by-product in the sulphate pulping of coniferous wood. The supply of pine stumps for the production of wood rosin is decreasing and, today, the major types produced are gum rosin and tail-oil rosin. In technical literature, the term colophony corresponds to gum rosin. In dermatological literature, tail-oil rosin and wood rosin are also included in the term colophony , since the resins contain the same major chemical components and allergens and are used in various technical products, regardless of the source. In American literature, the term rosin is more frequently used. 

China, Latin American countries and Portugal are great producers of gum rosin. USA, Finland, Sweden and the countries of the former USSR are great producers of tail-oil rosin. Approximately i.i million tons of colophony are produced annually, and the absolute majority is chemically modified to various derivatives. 

Reagent Chemicals, American Chemical Society Specifications," Am. Chemical Soc., Washington, DC. For suggestions on the testing of reagents not listed by the American Chemical Society, see Reagent Chemicals and Standards, by Joseph Rosin, D. Van Nostrand Co., Inc., New York, NY, and the United States Pharmacopeia."... 

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