Tetra-chlorophenol

A difference is observed in the pattern of PCDDs and PCDFs in the blood between the workers exposed to 2,3,, 6-tetra-chlorophenol or pentachlorophenol. This difference parallels the difference in contaminants in these two products. 

Dichlorophenol and 2,4,5-trichlorophenol have been used in the synthesis of phenoxy acid herbicides, including 2,4-dichlorophenoxyacetic acid (2,4-D) and 2,4,5-tri-chlorophenoxyacetic acid (2,4,5-T). 2,4,5-Trichlorophenol has also been used as a fungicide and a bactericide. 2,4,6-Trichlorophenol has been used as a pesticide. 2,3,4,6-Tetra-chlorophenol has been used as a fungicide (Lewis, 1993 Verschueren, 1996). Chlorophenols have also been formulated and used as salts in some applications. 

Fig. 4.30. Effect of desorption time on signal height. Sample spiked with chlorophenols and narrow-bore liner. ( ) 3-chlorophenol, ( ) 2,5-dichlorophenol, (A) 2,3,5-trichlorophenol, (-(-) 2,3,4,6-tetra-chlorophenol. (Reproduced with permission of Elsevier.)...

Tetra- chlorophenol 100 23 28 7 Very slight clouding/discoloration expected life months to years Tyril Dow Chemical Specimen In accordance with ASTM D543-84... 

Determination of C -C cai bonyl compounds, phthalic acid alkyl esters, mutagen MX and its geometric isomer E-MX, chlorophenols, organochlorine pesticides (OCPs) - a-, P-, J-, 5-HCH, DDE, DDD, DDT, total isomeric-specific content of polychlorinated byphenyls (PCBs) (tri-, tetra-, penta-, hexa-, hepta-, octachloroisomers) in SCAN and SIM mode was canned out. MDE of procedure for OCPs makes up 0.01-0.1 and PCBs - 0.17-0.38 ng/1 at enrichment factor K = (1.50-4.00)T0. ... 

Dichlorodibenzo-p-dioxin was prepared from isotopic potassium 2,4-dichlorophenate uniformly labeled with Ullman conditions gave a 20.5% yield. Small amounts of dichlorophenoxy chlorophenol were removed from the product by extraction with sodium hydroxide before purification by fractional sublimation and recrystallization from anisole. Chlorination of 2,7-dichlorodibenzo-p-dioxin in chloroform solution containing trace amounts of FeCls and 12 yielded a mixture of tri-, tetra-, and pentachloro substitution products. Purification by digestion in boiling chloroform, fractional sublimation, and recrystallization from anisole was effective in refining this product to 92% 2,3,7,8-tetrachloro isomer, which also contained 7% of the tri- and 1% of the penta-substituted dibenzo-p-dioxin. Mass spectroscopy was used exclusively to monitor the quality of the products during the synthesis. 

PCP presents a different picture from that of the lower chlorophenols and their derivatives. The corresponding dioxin shows much more stability to light than does TCDD, enough to permit its prolonged existence at low concentrations in a photoreactor. As a phenol it can directly yield dioxins, a process favored by its normal mode of application as the sodium salt. Although octachlorodibenzo-p-dioxin has much lower mammalian toxicity than TCDD (6), its formation, properties, and effects demand additional investigation. Technical preparations of PCP are frequently mixtures of tetra- and pentachlorophenols consequently, hepta-and possibly hexachlorodibenzo-p-dioxins might be expected as photolysis products in addition to the octachloro derivative. 

This voluntary risk assessment programme started in 1995 and concerned a list of 25 chemicals dichloromethane, chloroform, tetrachloromethane, 1,2-dichloroethane, 1,1,1-trichloroethane, 1,1,2-trichloroethane, vinyl chloride, trichloroethene, tetra-chloroethene, hexachlorobutadiene, monochlorobenzene, 1,4-dichlorobenzene, 1,2-dichlorobenzene, 1,2,4-trichlorobenzene, tetrachlorobenzene, hexachlorobenzene, 2-chlorophenol, 3-chlorophenol, 4-chlorophenol, pentachlorophenol, hexachloro-cyclohexane, dioxins, PCB, DDT, and elemental mercury. 

Soil Under anaerobic conditions, pentachlorophenol may undergo sequential dehalogenation to produce /n-chlorophenol, tetra-, tri-, and dichlorophenols (Kobayashi and Rittman, 1982). In aerobic and anaerobic soils, pentachloroanisole was the major metabolite, with minor quantities of... 

C. Chlorophenols. Chlorophenols have been extensively used since the 1930 s as insecticides, fungicides, mould inhibitors, antiseptics and disinfectants. The annual production volume is estimated to be in the order of 150 000 tons. In the US penta-chlorophenol is the second heaviest in use of all pesticides (38). The most important use of 2,U,6-tri, 2,3,, 6-tetra- and pentachlorophenol (or their salts) is for wood protection. Penta-chlorophenol is also used as a fungicide for slime control in the manufacture of paper pulp and for a variety of other purposes such as in the tanning process of leather and an additive in cutting oils and fluids, paint, glues and out-door textiles. 

Levin et al. (52) have studied the levels of chlorophenols and dibenzofurans in wood dust samples and sludge from two Swedish sawmills. Both plants were using the Finnish 2,3,, 6-tetra-chlorophenate, see Table III for the levels of impurities. The results from this study are collected in Table VI. 

Because Fenton oxidation of chlorophenols should follow the same mechanism, the activated complex in the transition state should have a similar structure. Therefore, Equation (6.64) can be applied to mono-, di-, and trichlo-rophenols. It is not certain, however, that it can be applied to tetra- and penta-chlorophenols due to steric hindrance therefore, when the above general equation is applied to chlorophenols, the equation becomes ... 

Properties of PCDEs, including physicochemical ones, are not well known as the literature reviews of PCDEs have shown [4, 11,40,46]. PCDEs resemble PCBs structurally and in their chemical and physical properties, which, like PCDDs, PCDFs, and related compounds, are known to be stable and resistant to breakdown by heat, hydrolysis, bases, and acids. PCBs are also quite stable to oxidation under moderate conditions [3], but there is not much data about PCDEs concerning their stability. There is some evidence that PCDEs are resistant to bases and acids and the occurrence of PCDEs in the environment indicates that PCDEs are persistent and bioaccumulating compounds. The study of Firestone et al. [37] already showed that PCDEs are quite stable, since PCDEs could be measured in chlorophenol extracts after sulfuric acid treatment. Tetra- and octachlorinated PCDE congeners were later proven resistant in treatment with... 

In terrestrial ecosystems, there is extensive data suggesting that some agrochemicals are more toxic to birds than to mammals. In addition, terrestrial worms may accumulate xenobiotics or their metabolites and thereby transfer these compounds to birds. For example, the concentration in earthworms has been demonstrated both of chlorophenols (van Gestel and Ma 1988) and of their microbial transformation products pentachloroanisole and 2,3,4,6-tetra-chloroanisole (Palm et al. 1991). The consumption of these compounds by predators such as birds is an obvious possibility for their further dissemination. 

Presence of dioxins in pesticides in general Woolson et al. (1972) examined 129 samples of 17 different pesticides derived from chlorophenols for polychlorinated dibenzo-p-dioxins. The tetra derivatives were found primarily in 2,4,5-T samples. Twenty of 42 samples contained more than 0.5 ppm. The presence of TCDD in some pesticides is easy to understand due to the chemical reactions used for its synthesis. The herbicide 2,4,5-T is produced by condensing 2,4,5-trichlorophenol with chlo-roacetic acid in the presence of NaOH at 105°C to yield the sodium salt of 2,4,5-T. Trichlorophenol may be made by the action of alkali on 1,2,4,5-tet-rachlorobenzene produced by chlorination of the trichlorobenzenes resulting from dehydrochlorination of benzene hexachloride (BHC). Today most countries will not approve a pesticide without data on dioxin content. 

When performed under similar conditions, gaseous hydrochloric acid formed during the chlorination process hardly creates any isomerization of polychlorinated gem-dichlorocyclohexadienones to chlorophenols. This difference in reactivity explains why it is necessary to use either a strong acid or a Lewis acid to reach the tetra or penta stage. 

F027 - Discarded unused formulations containing tri-, tetra-, or pentachlorophenol or discarded unused formulations containing compounds derived from these chlorophenols. (This listing does not include formulations containing hexachlorophene synthesized from prepurified 2,4,5-TCP as the sole component.)... 

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