Chlorinated phenolics

Hypochlorite readily chlorinates phenols to mono-, di-, and tri-substituted compounds (163). In wastewater treatment chlotophenols ate degraded by excess hypochlorite to eliminate off-flavor (164). Hypochlorite converts btomoben2ene to cb1oroben2ene in a biphasic system at pH 7.5—9 using phase-transfer catalysts (165). 

Dichlorophenols. Among all the dichlorophenols, C H Cl O, it is 2,4-dichlorophenol that is produced in greatest quantity. 2,4-Dichlorophenol is used in manufacturing 2,4-dichlorophenoxyacetic acid [94-75-7] (2,4-D) and 2-(2,4-dichlorophenoxy)propionic acid [720-36-5] (2,4-DP). Industrially, 2,4-dichlorophenol can be obtained by chlorinating phenol, -chlorophenol, o-chlorophenol, or a mixture of these compounds in cast-iron reactors. The chlorinating agent may be chlorine or sulfuryl chloride in combination with a Lewis acid. For example ... 

Authors are designed row sensitive and selective test-systems for analysis of heavy metals, active chlorine, phenols, nitrates, nitrites, phosphate etc. for analysis of objects of an environment and for control of ions Ee contents in the technological solutions of KH PO, as well as for testing some of pharmacological psychotropic daigs alkaloids (including opiates), cannabis as well as pharmaceutical preparations of phenothiazines, barbiturates and 1,4-benzodiazepines series too. 

M. H. Liu, S. Kapila, K. S. Nam and A. A. Elseewi, Tandem supera itical fluid extr action and liquid cliromatogr aphy system for determination of chlorinated phenols in solid matrices , 7. Chromatogr. 639 151-157 (1993). 

A biopolymer produced by a particular strain of bacteria is becoming widely used as a substitute for clay in low-solids muds. Since the polymer is attacked readily by bacteria, a bactericide such as paraformaldehyde or a chlorinated phenol also must be used with the biopolymer. The system has more stable properties than the extended bentonite system, because biopolymer exhibits good rheological properties in its own right, and has a better tolerance to salt and calcium. The system can be formulated to include salt, such as potassium chloride. Such a system, however, would then be classed as a nondispersed inhibitive fluid. 

To select a microbiocide one should consider its compatibility with the system. Some chemicals may affect the performance of the drilling fluids and lead to other problems. For example, quats, amines, and chlorinated phenols may cause clay flocculation of the drilling fluid if present in sufficient quantities. Therefore, the effect of the microbiocide on the drilling fluid properties must be thoroughly tested and understood before the chemical is used. 

In addition lo its use in making resins and adhesives, phenol is also the starting material for the synthesis of chlorinated phenols and the food preservatives BHT (butylated hvdroxytoiuene) and BHA (butylated bydroxyanisole). Penta-chlorophenol, a widely used wood preservative, is prepared by reaction of phenol with excess CI2- The herbicide 2,4-D (2,4-dichlorophenoxyacetjc acid) is prepared from 2,4-dichlorophenol, and the hospital antiseptic agent hexa-chlorophene is prepared from 2,4,5-trichlorophenol. 

Veningerova M, Prachar V, Kovacicova J, et al. 1998. Levels of chlorinated phenols in Danube river water. Fresenius Environ Bull 7 224-231. 

PCDFs are similar in many respects to PCDDs but have been less well studied, and will be mentioned only briefly here. Their chemical structure is shown in Figure 7.1. Like PCDDs, they can be formed by the interaction of chlorophenols, and are found in commercial preparations of chlorinated phenols and in products derived from phenols (e.g., 2,4,5-T and related phenoxyalkanoic herbicides). They are also present in commercial polychlorinated biphenyl (PCB) mixtures, and can be formed... 

Thermal properties of several chlorinated phenols and derivatives were studied by differential thermal analysis and mass spectrometry and in bulk reactions. Conditions which might facilitate the formation of stable dioxins were emphasized. No two chlorinated phenols behaved alike. For a given compound the decomposition temperature and rate as well as the product distribution varied considerably with reaction conditions. The phenols themselves seem to pyro-lyze under equilibrium conditions slowly above 250°C. For their alkali salts the onset of decomposition is sharp and around 350°C. The reaction itself is exothermic. Preliminary results indicate that heavy ions such as cupric ion may decrease the decomposition temperature. 

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. 

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). 

Fig. 10.7 Structural formulae of phenolic disinfectants A, clear soluble fluids B, black and white fluids C, chlorinated phenols D, bisphenols.

Haggblom M, D Janke, PJM Middeldorp, M Salkinoja-Salonen (1988) O-Methylation of chlorinated phenols in the genus Rhodococcus. Arch Microbiol 152 6-9. 

Neilson AH, A-S Allard, P-A Hynning, M Remberger, L Landner (1983) Bacterial methylation of chlorinated phenols and guiaiacols formation of veratroles from gnaiacols and high molecular weight chlorinated lignin. Appl Environ Microbiol 45 774-7S3. 

Campbell LM, DCG Muir, DM Whittle, S Backus, RJ Nostrum, AT Fisk (2003) Hydroxylated PCBs and other chlorinated phenolic compounds in lake trout (Salvelinus namaycush) blood plasma from the Great Lakes region. Environ Sci Technol 37 1720-1725. 

Chlorinated phenols are used for the impregnation of timber and the production of phenoxyalkano-ate herbicides that are degraded by dioxygenation to chlorophenols. 

The degradation of chlorinated phenols has been examined with the white-rot basidiomy-cete Phanerochaete chrysosporium under conditions of nitrogen limitation, and apparently involves both lignin peroxidase and manganese-dependent peroxidase activities (Valli and Gold 1991). 

A facultatively anaerobic organism designated Anaeromyxobacter dehalogenans (Sanford et al. 2002) was capable of dechlorinating ortho-chlorinated phenols using acetate as electron donor—2-chlorophenol was reduced to phenol and 2,6-dichlorophenol to 2-chloro-phenol (Cole et al. 1994). A strain of Desulfovibrio dechloracetivorans was also able to couple the dechlorination of ortho-substituted chlorophenols to the oxidation of acetate, fumarate, lactate, and propionate (Sun et al. 2000). 

Ahlborg UG, TM Thunberg (1980) Chlorinated phenols occurrence, toxicity, metabolism, and environmental impact. CRC CritRev Toxicol 1 1-35. 

Dec J, J-M Bollag, (1994) Dehalogenation of chlorinated phenols during oxidative coupling. Environ Sci Technol 28 484-490. 

With suitable adjustments to the temperature, also subcritical water extraction (SWE) or pressurised hot water extraction (PHWE) allows selective extraction of polar (chlorinated phenols), low-polarity (PCBs and PAHs) and nonpolar (alkanes) organic compounds from industrial soils [418]. 

Analytical methods for 12 chlorinated phenolics and adsorbable organic halides (AOXs). Samples of air emissions and water discharges from each mill must be tested using the laboratory methods included in the rule. The new methods will enable more timely and accurate measurements of releases of these pollutants to the environment and will be used to ensure compliance with air emission and water discharge permit limits... 

For kraft pulp mills, the Cluster Rules add toxic and nonconventional pollutants to the list of regulated pollutants only for bleached papergrade kraft mills. Effluent limitations guidelines and standards were added for the following BAT and PSES pollutants (and NSPS/PSNS for new sources) chloroform, 2,3,7,8-TCDD, 2,3,7,8-TCDF, 12 chlorinated phenolic compounds, and AOX. All of the... 

Chlorinated phenolic compounds. Chlorinated phenolic compounds include phenols, guaiacols, catechols, and vanillins substituted with from one to five chlorine atoms per molecule. Typically, bleaching processes that result in the formation of 2,3,7,8-TCDD and... 

Sharma H, Barber JT, Ensley HE, Polito MA (1997) A comparison of the toxicity of phenol and chlorinated phenols by Lemna gibba with reference to 2,4,5-trichloorophenol. Environ Toxicol Chem 16 346—350... 

The photocatalytic activity of ZnO nanomaterials for the degradation of some organic pollutants in water [173] (e.g., dyes [174]) was explored by several groups to achieve environmental benefits. Recent studies have indicated that ZnO can be used under acidic or alkaline conditions with the proper treatment [175,176]. ZnO nanomaterials were used as photocatalysts for the degradation of phenol [177] and chlorinated phenols such as 2,4,6-trichlorophenol [178]. ZnO nanomaterials were also used for the degradation of Methylene Blue [179], direct dyes [180], Acid Red [181], and Ethyl Violet [182],... 

When chlorinated phenols are heated for analytical purposes with calcium hydroxide-potassium nitrate mixtures, chlorinated benzodioxins analogous to the extremely toxic tetrachlorodibenzodioxin may be formed. 

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