Preservatives in wood

Initially used as a preservative in wood paints and metalworking fluids, iodopropynylbutylcarbamate is being increasingly used in cosmetics (1). 

Preservatives. Although not classified generally as wood finishes, preservatives in wood do protect against weathering and decay, and a great quantity of preservative-treated wood is exposed without any additional finish (2). There are three main types of preservative ... 

Hexafluorosilicates are mainly used as preservatives in wood protection (particularly magnesium hexafluorosilicate). Sodium hexafluorosilicate is used in water fluoridation. 

Ibach RE (1999) Wood preservation. In Wood handbook - wood as an engineering material. 

Humar M, Petrie M, Pohleven F, Sentjurc M. 2002. Consumption of O2, evolution of CO2 and reduction of Cr(VI) during fixation of chromium based wood preservatives in wood. Wood Sci Technol 36(4) 309-318. 

Other apphcations of sodium bromide iaclude use ia the photographic iadustry both to make light-sensitive silver bromide [7785-23-1] emulsions and to lower the solubiUty of silver bromides during the developing process use as a wood (qv) preservative in conjunction with hydrogen peroxide (14) as a cocatalyst along with cobalt acetate [917-69-1] for the partial oxidation of alkyl side chains on polystyrene polymers (15) and as a sedative, hypnotic, and anticonvulsant. The FDA has, however, indicated that sodium bromide is ineffective as an over-the-counter sleeping aid for which it has been utilized (16). 

In the case of low temperature tar, the aqueous Hquor that accompanies the cmde tar contains between 1 and 1.5% by weight of soluble tar acids, eg, phenol, cresols, and dihydroxybenzenes. Both for the sake of economics and effluent purification, it is necessary to recover these, usually by the Lurgi Phenosolvan process based on the selective extraction of the tar acids with butyl or isobutyl acetate. The recovered phenols are separated by fractional distillation into monohydroxybenzenes, mainly phenol and cresols, and dihydroxybenzenes, mainly (9-dihydroxybenzene (catechol), methyl (9-dihydtoxybenzene, (methyl catechol), and y -dihydroxybenzene (resorcinol). The monohydric phenol fraction is added to the cmde tar acids extracted from the tar for further refining, whereas the dihydric phenol fraction is incorporated in wood-preservation creosote or sold to adhesive manufacturers. Naphthalene Oils. Naphthalene is the principal component of coke-oven tats and the only component that can be concentrated to a reasonably high content on primary distillation. Naphthalene oils from coke-oven tars distilled in a modem pipe stiU generally contain 60—65% of naphthalene. They are further upgraded by a number of methods. 

L. E. Gjovik and H. L. Davidson, Comparison of Wood Preservatives in Stake Pests, Research Note EPL 02, U.S. Department of Agriculture, Eorest Service, Eorest Products Laboratory, Madison, Wise., 1979. 

The largest use of zinc chloride in the United States is in wood preservation, fluxes, and batteries (see Batteries). Zinc chloride solution dissolves vegetable fiber and is widely used in mercerizing cotton (qv), swelling fibers, as a mordant in dyeing, parchmentizing paper, etc (see Fibers, vegetable ... 

Disodium Oetaborate Tetrahydrate, Commercially available products, having the approximate composition of a hypothetical disodium octaborate tetrahydrate, have found apphcation in wood (qv) preservatives, fertilizer sprays, insecticides, herbicides, and fire retardants. In many apphcations the large water solubihty of these products is an asset. 

Salts of neodecanoic acid have been used in the preparation of supported catalysts, such as silver neodecanoate for the preparation of ethylene oxide catalysts (119), and the nickel soap in the preparation of a hydrogenation catalyst (120). Metal neodecanoates, such as magnesium, lead, calcium, and zinc, are used to improve the adherence of plasticized poly(vinyl butyral) sheet to safety glass in car windshields (121). Platinum complexes using neodecanoic acid have been studied for antitumor activity (122). Neodecanoic acid and its esters are used in cosmetics as emoUients, emulsifiers, and solubilizers (77,123,124). Zinc or copper salts of neoacids are used as preservatives for wood (125). 

A few acid woods, such as oak, chestnut and Western red cedar, accelerate surface weathering of aluminium, but do not usually give rise to serious attack . Timber preservatives containing soluble copper compounds should be avoided creosote and zinc napthenate are satisfactory preservatives for wood in contact with aluminium. 

Ross, F. F. and Wood, M. J., The Preservation of Wood in Water Cooling Towers. BWPA Annual Convention Record, pp. 171-197 (1957)... 

Henningsson, B. and Jermer, J., Studies on Corrosion of Metallic Obiects in Contact with Preservative-Treated Wood in the Open, Report No. 144, Swedish Wood Preservation Institute, Stockholm (1982)... 

FIGURE 79 Bone carving. A seventh-century b.c.e. decorative carving on bone that was inlayed in wood, Tel Malhata, Israel. Bone has been crafted into practical and decorative objects since the dawn of time. Bone carvings hold great detail, and the surface polish that can be achieved is high. Many bone-made objects have survived, partly because it was widely used, but also because buried bone is generally well preserved in many types of soil. 

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... 

Copper compounds are used in agriculture to treat mildew and other plant diseases in the food industry as preservatives, additives, or coloring agents in preservatives of wood, leather, and fabrics in coin manufacture and in water treatment (ATSDR1990 Roncero et al. 1992). The use of copper-containing pesticides is traditional along the Mediterranean Coast, especially the use of Bordeaux mixture, a copper sulfate-based fungicide that has been widely used for more than a century to... 

Analyses of the quantities of various treated timbers used in various countries have been performed and some examples are given herein to illustrate the scale involved. In 1990, 1967 600 m of preservative-treated wood and 327 000 m of anti-sapstain treated wood was used in the UK (Jermer, 1990). Of this total, 68 900 m was composed of poles and sleepers, sawn/other wood products comprised 1484 600 m (75%) and fencing... 

Due to environmental concerns regarding the use of certain classes of preservatives, there has recently been a renewed interest in wood modification. Wood modification represents a process that is used to improve the material properties of wood, but produces a material that be disposed of at the end of a product life cycle without presenting an environmental hazard any greater than that associated with the disposal of unmodified wood. Although wood modification has been the subject of a great deal of study at an academic level for over 50 years, it is only comparatively recently that there has been significant commercial development. 

---