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By chlorination phenol

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 ... [Pg.79]

Bro-Rasmussen F, Lokke H. 1984. Ecoepidemiology a casuistic discipline describing ecological disturbances and damages in relation to their specific causes exemplified by chlorinated phenols and chlorophenoxy acids. Reg Toxicol Pharmacol 4 391-399. [Pg.329]

Chlorinated phenols, such as 2,4-D, are formed by chlorinating phenol. [Pg.404]

The diazonium salts usually decompose when warmed with water to give a phenol and nitrogen. When treated with CuCl, CuBr, KI, the diazo group is replaced by chlorine, bromine or iodine respectively (Sandmeyer reaction). A diazonium sulphate and hydroxyl-amine give an azoimide. The diazonium salt of anthranilic acid (2-aminobenzoic acid) decomposes to give benzyne. ... [Pg.133]

DicblorobenzotnfIuoride. This compound is produced by chlorination of 4-chloroben2otrifluoride and exhibits sufficient activation to undergo nucleophilic displacement with phenols to form diaryl ether herbicides, eg, acifluorofen sodium [62476-59-9]. [Pg.331]

Trilialophenols can be converted to poly(dihaloph.enylene oxide)s by a reaction that resembles radical-initiated displacement polymerization. In one procedure, either a copper or silver complex of the phenol is heated to produce a branched product (50). In another procedure, a catalytic quantity of an oxidizing agent and the dry sodium salt in dimethyl sulfoxide produces linear poly(2,6-dichloro-l,4-polyphenylene oxide) (51). The polymer can also be prepared by direct oxidation with a copper—amine catalyst, although branching in the ortho positions is indicated by chlorine analyses (52). [Pg.330]

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). [Pg.469]

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. [Pg.674]

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. [Pg.629]

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... [Pg.152]

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. [Pg.26]

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. [Pg.32]

Chlorinated phenols are used for the impregnation of timber and the production of phenoxyalkano-ate herbicides that are degraded by dioxygenation to chlorophenols. [Pg.482]

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... [Pg.309]

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],... [Pg.232]

Schellenberg, K., Leuenberger, C., Schwarzenbach, R. P. (1984) Sorption of chlorinated phenols by natural sediments and aquifer materials. Environ. Sci. Technol. 18, 652-657. [Pg.56]

Physical state White solid with needle-like crystals. Produced by chlorination of molten phenol. Technical-grade material is dark gray to brown... [Pg.1196]

Steiert, J.G., J.J. Pignatello, and R.L. Crawford. 1987. Degradation of chlorinated phenols by a pentachlo-rophenol-degrading bacterium. Appl. Environ. Microbiol. 53 907-910. [Pg.1233]

Tee et al. [15] described an acetone-hexane extraction procedure followed by electron capture gas chromatography for the determination of down to lpg kg-1 chlorinated phenols in sediments. [Pg.161]

Phenol and substituted phenol compounds (Fig. 19) are known to be widespread as components of industrial wastes. These compounds are made worldwide in the course of many industrial processes, as for example in the manufacture of plastics, dyes, drugs, and antioxidants, and in the pulp and paper industry. Organophosphorus and chlorinated phenoxyacids also yield chlorinated and nitrophenols as major degradation products. 4-Nitrophenol was reported as a breakdown product after the hydrolysis and photolysis of Parathion in water and chlorinated phenols are formed by the hydrolysis and photolysis of chlorinated phenoxyacid herbicides [251-253]. [Pg.41]

Wajon JE, Rosenblatt DH, Burrows EP. 1982. Oxidation of phenol and hydroquinone by chlorine dioxide. Environ Sci Technol 16 396-402. [Pg.230]

They are attacked by chlorine water, oxidizing agents, concentrated sulfuric and nitric acids, halogens, and phenols. [Pg.563]

Figure 4. Separation of twelve different chlorinated phenols by conventional HPLC. The solutes are listed in Table I. Figure 4. Separation of twelve different chlorinated phenols by conventional HPLC. The solutes are listed in Table I.
Molds and other plant diseases are controlled by fungicides, which act to affect the growth or metabolism of fungal pests. Many different fungicides exist, including sulfur, aryl- and alkyl-mercurial compounds, Aw-dithiocarbamates, and chlorinated phenols. [Pg.256]


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See also in sourсe #XX -- [ Pg.261 ]




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By chlorination

Chlorinated phenolics

Chlorine phenols

Phenols, chlorinated

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