Structures pentachlorophenol

Hodson, P.V., R. Parisella, B. Blunt, B. Gray, and K.L.E. Kaiser. 1991. Quantitative structure-activity relationships for chronic toxicity of phenol, p-chlorophcnol, 2,4-dichlorophenol, pentachlorophenol, p-nitro-phenol and 1,2,4-trichlorobenzene to early life stages of the rainbow trout (Oncorhynchus mykiss). Canad. Tech. Rep. Fish. Aquat. Sci. 1784. 56 pp. 

Then there are a number of pesticides, e.g. the phenolic herbicide dinoseb and the fungicide pentachlorophenol, whose speciation varies strongly in the environmental pH-range. For this reason, one has to consider the pwhen estimating their environmental fate. Structures of the compounds discussed in this section are depicted in Table 1, together with a listing of their pand octanol-water partition coefficients, Kow, of the neutral species (unless otherwise indicated). Typical basic pollutants include the industrial chemicals aniline and jV.jV-dimethylaniline. 

The fungal enzyme from R. praticola was able to catalyze the oxidative coupling of pentachlorophenol (PCP) and syringic acid, a representative of phenol carboxylic acids from lignin occurring in HS structures. 

Chemically, creosote is a mixture of a great number of compounds, almost exclusively of cyclic structure. Individual compounds present in creosote in concentrations of 2-4% are acenaphthene, fluorene, diphenylene oxide, anthracene, and carbazole. Only one compound, phenanthrene, is present in a larger concentration (12-14%). For many years, chemists in many countries have tried tu isolate individual compounds and to find profitable uses for them. Most of these attempts have failed with exception of those involving anthracene. See also Anthracene. The principal use of creosote is for preservation of wood. Railroad lies, poles, fence posts, marine pilings, and lumber for outdoor use are impregnated with creosote in large cylindrical vessels. If properly treated, the life of the wood is greatly extended. Materials that are competitive with creosote for wood-preservation purposes include various petroleum oils, and pentachlorophenol. Pentachlorophenol is used in solutions of creosote or of petroleum oils. Blends of creosote with petroleum oils also are used for economic reasons. 

Figure 16.7 Structural formulas of Alachlor, pentachlorophenol, and microcidal hexachlorophene and triclosan.

This paper will consider the efficacy or horse-radish peroxidase (HPR) for the removal of 2-chlorophenol — a taste and odor compound, and pentachlorophenol — a wood preservative sometimes found as a contaminant in drinking-water. These compounds were evaluated at low as well as high concentrations, and in the presence of potential competing compounds. Competing compounds may be innocuous aromatic compounds or other specific micro pollutants. Humic substances are organic compounds composed mainly of aromatic structures [ 14 ] which account for up to 90% of the background total organic carbon (TOC) in natural waters [15 ]. Recent studies have indicated th t the presence of humic acids may deactivate horse-radish peroxidase [16 ]. 

In the 1960s, paneling and other interior wood structures were treated with pentachlorophenol and gamma-hexachlorohexane for preservation purposes. Those preservatives contain trace quantities of polychlorinated diben-zo-p-dioxins and -furans that can volatilize into indoor air and impact the human immune system, particularly when the treated woods are being sanded and refinished, even many years after they were initially applied. 35 ... 

P NMR has been used to examine the effect of pentachlorophenol on the energy metabolism of abalone (Haliotis rufescens) (Tjeerdema et al. 1991), and the structures of the compounds formed by reaction of 1 2 and l 4benzoquinones with trimethylphosphite (Argyropou-los and Zhang 1998). 

The occurrence of the wood preservative pentachlorophenol (PCP), in groundwater is thought to arise from the manufacturing process involving treatment of poles. The chemical structure is shown below... 

Generally a quality problem is created when heavy chlorophenols (trichlorophenols, tetrachlorophenols and pentachlorophenols) are processed. Impurities such as polychlorophenoxyphenols, polychlorodibenzodioxins, polychlorodibenzofurans and polychlorodihydroxybiphenyls, are quite often found in some industrial products. Table 3 below shows the influence of the structure of the series of dibenzodioxins on the DL 50 (refs. 2, 3) (number and position of the chlorine atoms). 

Figure 14. Structure of pentachlorophenol. Positions 2 and 6 are the ortho-positions, 3 and 5, the meta-positions, and 4, the para-position (Diehl and Borazjani, 1999).

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