Production of wood

Wood Delignijication. The production of wood pulp (qv) for the paper (qv) industry consists of removing lignin (qv) from wood chips, thus freeing the ceUulose fibers. An aqueous solution containing 30—70 wt % sulfolane efficiently extracts the lignin from aspen. Western hemlock, and Southern pine wood chips. Pulp yields are from 50—75% (43,44). 

J. F. Saeman, E. G. Locke, and G. K. Dickerman, Production of Wood Sugar in Germany and its Conversion to Yeast and Mlcohol, U.S. Department of Commerce Office Technical Service PB Report 7736, U.S. Department of Commerce, Washington, D.C., 1945. 

Both the wood-based panel industry and the adhesive industry show a high commitment to and great capability towards innovation. The best evidence for this is the considerable diversity of types of adhesives used for the production of wood-based panels. Well-known basic chemicals have been used for a long time for the production of the adhesives and their resins, the most important ones being formaldehyde, urea, melamine, phenol, resorcinol and isocyanate. The greater portion of the currently used adhesive resins and adhesives for wood-based panels is produced with these few raw materials. The how to cook the resins and the how to formulate the adhesive become more and more complicated and sophisticated and are key factors to meet today s requirements of the wood-based panel industry. 

For the production of wood-based panels various adhesives are in use like aminoplastic resins (UF, MU(P)F), phenolic resins (PF) or isocyanate (PMDI). The proper choice of the adhesive depends on the required properties of the wood-based panels, on the working conditions during the production as well as often on the costs for the adhesive system this not only means the net price of the adhesive but the overall costs of the gluing system including glue spread factor. 

During the production of wood-based panels, part of the adhesive penetrates into the wood surface. An overpenetration causes starved glue lines, whereas a low penetration limits the contact surface between wood and the adhesive low penetration often is the consequence of bad wetting behavior. 

Kharazipour, A., Hiitterman, A., Biotechnological production of wood composites. In Bruce, A. and Palfreyman, J.W. (Eds.), Forest Products Biotechnology, Ch. 9. Taylor and Francis, London, 1998, pp. 141-150. 

Chlorinated phenols have been traditionally applied in the production of wood preservatives, insecticides and disinfectants. Common chlorinated phenols found in wood preservatives are 2,3,4,6-tetrachlorophenol (TeCP), 2,4,6-trichlorophenol... 

Suida An extractive distillation process for concentrating the dilute acetic acid obtained from the manufacture of cellulose acetate. It was originally used for separating the products of wood pyrolysis. Invented in 1926 by H. Suida in Vienna and operated in the 1930s. 

The process of tree growth utilizes atmospheric carbon in the production of wood biomass. Furthermore, this sequestered carbon can continue to be held in products that are manufactured from wood. Although much research has been done in investigating forests as actual or potential carbon sinks, there has been rather less work looking at the implications of the use of wood products as a medium-term carbon store. 

Kharazipour, A., Hiittermann, A. and Luedemann, H.D. (1997). Enzymatic activation of wood fibres as a means of the production of wood composites. Journal of Adhesion Science and Technology, 11(3), 419-4 27. 

Xyloisosaccharinic acid [2,4-dihydroxy-2-(hydroxymethyl)butanoic acid] is one of the major, alkaline-degradation products of wood xylan, in particular, that of birch. The disaccharide, 2-O-D-xylopyranosyl-L-arabinose, which was isolated as a hydrolysis product of corn-cob hemicellulose, is readily degraded at 100° in 15 mM Ca(OH)2 to acidic products, primarily saccharinic acids. Xylan oligosaccharides from corn-cob hemicellulose produced 2,4-dihydroxy-2-(hydroxymethyl)buta-noic acid when exposed to 0.02 M Ca(OH)2 at 25°. However, it was noted that the xylan, itself, was stable at 100° in Af NaOH. The major acidic component of the hemicellulose fraction of slash pine Pinus el-liotti) after acid hydrolysis was identified as 4-O-methyl-D-glucuronic... 

Hexanone, also known as methyl n-butyl ketone or MBK, is a clear, colorless liquid with a somewhat sharp odor. The liquid form can easily evaporate into the air as a vapor. It is a waste product of wood pulping, coal gasification, and oil shale operations. 2-Hexanone was formerly used in paint and paint thinner and in various chemical substances. However, since it was found to have harmful health effects, it is no longer made in the United States, and its uses have been restricted. There are no known major natural sources of 2-hexanone in the environment. When 2-hexanone is released to rivers or lakes, it dissolves very easily, and it may evaporate into the air in a few days. We do not know if 2-hexanone binds to soil. When 2-hexanone is released to the water, air, or soil, it is probably broken down into smaller products, possibly within a few days. 

Composites Both UV and EB cures are employed for the production of wood composite materials and in fiber-reinforced composites for aircraft and aerospace applications. The EB technology has been successful in the manufacture of large structures that exceed the size of autoclaves, and in curing adhesive joints in cases where uniform radiation can be provided more easily than uniform heat. In industrial and consumer applications, multiple combinations of different reinforcing fibers can be co-cured in one cycle by EB with considerably lower residual stresses than those introduced by thermal cure.16... 

The gas is used in various chemical industries. For example, it forms an intermediate stage in the production of sulphuric acid and of sulphites it is also applied in the preparation of chemical substances such as selenium, tellurium, quinol, etc. To some extent sulphur dioxide finds application for fire-prevention and -extinguishing, and much is used in the form of alkali sulphite in the production of wood pulp for paper and artificial silk manufacture. 

On a heavy tonnage basis, cellulose is important as a raw material in the production of wood pulp and paper. See also Papermaking and Finishing. 

The pyrolysis products of wood can be broadly grouped into three categories as shown in Scheme 3, i,e., the combustible... 

TABLE VII. PYROLYSIS PRODUCTS OF WOOD AND TREATED WOOD AT 600°... 

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