Phenols pentachlorophenol

Alkylphenols, ammonia, asbestos, chlorinated paraffins, 4-chloroaniline, cyanide, detergents, di- -butyl phthalate, polyaromatic hydrocarbons (PAHs e.g. anthracene, benzopyrene, methylcholanthrene, /i-naphthoflavone), nitrate, nitrite, petroleum oil, phenol, pentachlorophenol, 4-nitrophenol, dinitro-o-cresol, polychlorinated biphenyls (PCBs especially coplanar), polychlorinated dioxins, polybrominated naphthalenes, /i-sitosterol, sulfide, thiourea, urea, acid water, coal dust... 

Gupta, P.K. and P.S. Rao. 1982. Toxicity of phenol, pentachlorophenol and sodium pentachlorophenate to a freshwater pulmonate snail Lymnaea acuminata (Lamarck). Arch. Hydrobiol. 94 210-217. 

According to the vendor, the CAV-OX technology treats contaminants such as halogenated solvents, phenol, pentachlorophenol (PCP) pesticides trichloroethene (TCE) polychlorinated biphenyls (PCBs) explosives benzene, toluene, ethylbenzene, and xylene (BTEiX) methyl tertiary butyl ether bacteria and virus strains and cyanide. 

Samples are transferred to a separatory funnel, surrogates are added, and an immiscible solvent (dichloromethane, hexane, etc.) is added. The liquids are shaken vigorously for a few minutes and then allowed to rest until a separation between the two phases occurs. The solvent is removed and the extraction process is repeated twice more. The extracts are combined, dried over anhydrous sodium sulphate, and processed further (cleanup) as required. Some laboratories have automated this tedious procedure by performing extractions in bottles. In this case, solvent and water are placed in a bottle and rotated (windmill rotators) or shaken (platform shakers) for 1—2 h. The lack of vigorous shaking is replaced by an extended time for extraction. Liquiddiquid extraction is used for all semivolatile analysis (hydrocarbons >C12, PAH, pesticides, PCB, dioxins). By lowering the pH, extraction of phenols (pentachlorophenol) and acidic compounds (2,4-dichlorophenoxyacetic acid—2,4-D) will be enhanced. Increasing the pH will increase extractability of basic (aromatic amines) and neutral compounds (PAH). 

Their adsorptive capacity for phenol, pentachlorophenol, dodecylbenzenesulphonate, and p-toluenesulphonate were measured [9 ] From these results the carbons J23 and J32 and the reference carbon F 400 (Calgon corporation) were selected to study the adsorption of humic substances. 

Table 5 shows the excellent adsorption characteristics of the home prepared carbons, in comparison with 3 of the 10 commercial carbons tested. The results obtained in the equilibrium adsorption study of phenol, pentachlorophenol, dodecylbenzenesulphonate, and p-toluenesulphonate were discussed in a previous paper [9 ]. Also this study showed a very good performance of the home produced carbons. Based on these results carbon J 23 and J 32 were selected for further research. 

Phenols (pentachlorophenol) 63-pm fraction of dust from bags of vacuum cleaners GC-ECD (derivatization) 0.1 Butte and Walker (1994)... 

Phenols (pentachlorophenol) Passively deposited suspended particulate GC-ECD (derivatization) 1 MeiBner and Schweinsberg (1996)... 

Chlorophenols (2-chlorophenol,2,4-dichloro-phenol, pentachlorophenol) Chlorophenylphenyl ether DDT and metabolites... 

Dinitro phenol Pentachlorophenol Resorcinol, Hydro-quinone, Pyrogallol Picric acid Aminoacids Buffer pH 4.6-4,8 HCOOH, CHsCOOH, C H COOH, C HgCOOH, Pivalic acid,... 

Like other phenols, pentachlorophenol Is a direct irritant, especially to the skin and upper respiratory tract. 

The synthesis of chlorarul [118-75-2] (20) has been improved. The old processes starting from phenol or 2,4,6-trichlorophenol have been replaced by new ones involving hydroquinone chlorination. These processes allow the preparation of chlorarul of higher purity, avoiding traces of pentachlorophenol. Different types of chlorination conditions have been disclosed. The reaction can be performed according to the following stoichiometry, operating with chlorine in aqueous acetic acid (86,87), biphasic medium (88), or in the presence of surfactants (89). 

Phenolics. Phenol (qv) and the chlotinated phenoHcs formerly comprised the largest class of iadustrial antimicrobials (see Chlorophenols). Table 5 shows the remaining phenoHcs of importance. Use of pentachlorophenol has been severely restricted only one manufacturer suppHes product for the wood preservation market. 

Important chemicals derived from phenol are salicylic acid acetylsali-cyclic acid (aspirin) 2,4-dichlorophenoxy acetic acid (2,4-D), and 2,4,5-triphenoxy acetic acid (2,4,5-T), which are selective herbicides and pentachlorophenol, a wood preservative ... 

Phenol 2,4,6-trichlorophenol p-chloro-m-cresol 2-chlorophe-nol 2,4-dichlorophenol 2,4,-dimethylphenol 2-nitrophenol 4-nitrophenol 2,4-dinitrophenol and pentachlorophenol... 

This fluorescent acid chloride can be used to form derivatives of alcohols, amines, and phenols. Using these fluorescent derivatives, an analysis of a series of n-alcohols from Ci to C4 was developed. A chromatogram produced by this technique is shown in Figure 3. Derivatives were also formed from ammonia, dimethylamine, and phenol. A derivative was formed from pentachlorophenol but was not fully characterized. The quantum yields of fluorescence of the alcohol derivatives of V were lower than those of the alkyl halide derivatives of III. 

In summary thermal decomposition of chlorinated phenols does not generally lead to dioxins. There are, however, several conditions which by themselves or combined would favor dioxin formation. First, of all chlorinated phenols either in bulk or in solution, only pentachlorophenol produced measurable amounts of dioxin. Secondly (Table II), only sodium salts in salid state reactions produced dioxins in reasonable yields. In contrast, the silver salt of pentachlorophenol (Figure 8) undergoes an exothermic decomposition at considerably lower temperatures and produced only higher condensed materials. No dioxin was detected. 

Chlorinated dibenzo ip-dioxins are contaminants of phenol-based pesticides and may enter the environment where they are subject to the action of sunlight. Rate measurements showed that 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is more rapidly photolyzed in methanol than octachlorodi-benzo-p-dioxin. Initially TCDD yields 2,3,7-trichlorodiben-zo-p-dioxin, and subsequent reductive dechlorination is accompanied by ring fission. Pure dibenzo-p-dioxin gave polymeric material and some 2,2 -dihydroxybiphenyl on irradiation. Riboflavin-sensitized photolysis of the potential precursors of dioxins, 2,4-dichlorophenol and 2,4,5-trichloro-phenol, in water gave no detectable dioxins. The products identified were chlorinated phenoxyphenols and dihydroxy-biphenyls. In contrast, aqueous alkaline solutions of purified pentachlorophenol gave traces of octachlorodibenzo-p-dioxin on irradiation. 

TJesticides derived from chlorinated phenols (Table I) are among the most prominent of those currently in worldwide use. Several major herbicides have been applied in large quantities in subtropical locations. Cahfornia used more than 1,200,000 pounds of 2,4-dichlorophenoxyacetic acid (2,4-D) and its derivatives in 1970 (I) Hawaii consumed some 465,000 pounds of pentachlorophenol (PCP) in 1968 (2), and the amount of combined butyl esters of 2,4-D and 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) released in one area of Cambodia during two months of 1969 was estimated to exceed 77,000 pounds (3). 

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. 

The most convenient and successful synthetic preparation of octa-chlorodibenzo-p-dioxin has been described by Kulka (13). The procedure involves chlorination of pentachlorophenol in refluxing trichlorobenzene to give octachlorodibenzo-p-dioxin in 80% yield. Kulka has explained the reaction as coupling between two pentachlorophenoxy radicals. Large amounts (5—15%) of heptachlorodibenzo-p-dioxin were observed in the unpurified product. Since the pentachlorophenol used in this study contained 0.07% tetrachlorophenol, we feel that tetrachloro-phenol may be produced in situ (Reaction 4). Such a scheme would be analogous to the formation of 2,4-dichlorophenol and 3-chlorophenol produced from 2,4,4 -trichloro-2 -hydroxydiphenyl ether (Reaction 2). The solubility of octachlorodibenzo-p-dioxin was determined in various solvents data are presented in Table II. 

Reagents. Substituted phenols, obtained commercially, were used unless otherwise noted phenols were analyzed by GLC to ensure 99+% purity. 2,4,5-Trichlorophenol and pentachlorophenol were purified by sublimation and recrystallization to yield product of 99+% purity. 

Initially formed polar metabolites such as phenols and amines may be conjugated to water-soluble terminal metabolites that are excreted into the medium and function as an effective mechanism of detoxification. For example, pentachlorophenol and pentachlorothiophenol produced from pentachloronitrobenzene conjugated represented the major metabolites. Although the naphthalene dihydrodiol was the major metabolite produced from naphthalene, the further transformation... 

Although the results of experiments on the dechlorination of pentachlorophenol (Bryant et al. 1991) enabled elucidation of the pathways to be elucidated, this study also revealed one of the limitations in the use of such procedures. Detailed interpretation of the kinetics of pentachlorophenol degradation using dichlorophenol-adapted cultures was equivocal due to carryover of phenol from the sediment slurries. 

Organic carboxylic acids are commonly found in foods, in the adipate process stream, and as pollutants. Fatty acids are the lipophilic portion of glycerides and a major component of the cell membrane. Phenols are widely used in polymers, as wood preservatives, and as disinfectants. Chloro-phenols such as 4-chlorophenol, two isomeric dichlorophenols, 2,4,6-tri-chlorophenol, three isomeric tetrachlorophenols, and pentachlorophenol were separated on a Dowex (The Dow Chemical Co. Midland, MI) 2-X8 anion exchange resin using an acetic acid-methanol gradient.138... 

The trend from heavy metal and phenolic based biocides, e.g. mercury and pentachlorophenol types, to more environmentally acceptable but less persistent organic types, requires more attention to plant hygiene (Figure 6, Briggs, 1980). 

Dinitrophenol 4,6 -Dinitro-o -cresol V-Nitrosodimethylamine V-Nitrosodiphenylamine V-Nitrosodi-n-propylamine Pentachlorophenol Phenol... 

---