1- Chloro-dibenzo dioxin

Table lll-G-IOO. Rate coefficients (fc, cm molecule s ) for reaction of O3 with 1 -chloro-dibenzo-/>-dioxin... 

The 1-chloro- and 2-chlorodibenzo-p-dioxins, which readily dissolved in TFMS acid, formed cation radicals without UV irradiation or the addition of oxidizing agents. With the exception of broader resonance lines. Figure 3 shows that the five-line pattern observed with 1-chloro-dibenzo-p-dioxin is similar to that of the unsubstituted dibenzo-p-dioxin. Apparently, protons at the 2, 3, 7, and 8 positions became less equivalent... 

Hewitt LM, JH Carey, KR Munkittrick, JL Parrott, KR Solomon, MR Servos (1998) Identification of chloro-nitro-trifluoromethyl-substituted dibenzo-/ -dioxins in lampricide formulations of 3-trifluoromethyl-4-nitrophenol assessment to induce mixed function oxidase activity. Environ Toxicol Chem 17 941-950. 

Tong et al. [227] have described a high-resolution gas chromatographic mass spectrometric method for the determination of monobromopoly-chloro-dibenzo-p-dioxin in soils and incinerator wastes. 

Harless RL, Lewis RG. 1989. Identification of bromo/chloro dibenzo-p-dioxins and dibenzofurans in ash samples. Chemosphere 18 201-208. 

Childers JW, Wilson NK, Harless RL, Barbour RK (1992), Chemosphere 25 1285-1290. Cha-racterization of brominated and bromo/chloro dibenzo-p-dioxins and dibenzofurans by gas chromatography/matrix isolation-infrared spectrometry"... 

Clement RE, Tosine HM (1988), Mass Spectrometry Reviews 7 593-636. The gas chromatogra-phy/mass spectrometry determination of chloro-dibenzo-p-dioxins and dibenzofurans" Donnelly JR, Munslow WD, Vonnahme TL, Nunn NJ, Hedin CM, Sovocool GW, Mitchum RK (1987), Biomed. Environ. Mass Spectrom. 14 465-472. The chemistry and mass spectrometry of brominated dibenzo-p-dioxins and dibenzofurans"... 

Chlorinated dioxins and dibenzofurans are not easily biodegraded in soils. Only a few of the microorganisms have shown some ability to degrade 2,3,7,8- TCDD (Matsumura and Benezet 1973). This isomer can accumulate in plants and animals, and its uptake by maize and bean plants from soil has been studied by Facchetti et al. (1985). The molecule does not appear to break down. Removal of dibenzofuran, dibenzo-p-dioxin and 2-chloro-p-dioxin at a concentration of 10 ppm each from the soil was achieved by... 

Nolan et al. [107] reported the adsorption of chloro dibenzo-p-dioxins on polyhydroxoaluminum montmorillonite. High distribution coefficients (ATp(ml/g) = amount X adsorbed per g solid (mg/g)/amount X in solution (mg/ml)) are obtained (octachloro dibenzodioxin on montmorillonite 2800 ml/g, on polyhydroxoaluminum montmorillonite 94000 ml/g). The distribution coefficient decreases sharply when the interlamellar polyhydroxoaluminum complexes are dehydrated to polyoxoaluminum pillars Kq = 1100 and 1800 ml/g for polyhydroxoaluminum montmorillonite heated to 170° and 550°C). 

Peldova, D., Navratil, T, Fenclova, Z., et al., 2011. Increased oxidative stress markers measured non-invasively in patients with long-lasting high 2A7,8-tetra-chloro-dibenzo-p-dioxin plasma level. Interdisciplinary Toxicology Conference TOXCON 2011, Prague, May 17-20, 2011. Interdisc. Toxicol. 4, A54. 

Kwok et al. (1995) measured an upper limit for the reaction of O3 with 1-chloro-dibenzo-p-dioxin, k <1 y. 10 cm molecule... 

This color transformation has been observed in dibenzo-p-dioxin (Structure I) and in its bromo, chloro, nitro, methyl, and ethyl derivatives in addition, the observed electron spin resonance (ESR) signals indicated the presence of paramagnetic species (2, 3). This phenomenon has been attributed to the formation of cation radicals in acid solution. 

The toxicity of chlorodibenzodioxins other than those evaluated in this study has not been reported. Purified samples of trichloro-, penta-chloro-, and heptachlorodibenzo-p-dioxin which are free of tetrachloro-and hexachlorodibenzo-p-dioxin need to be synthesized for study. However, heptachlorodibenzo-p-dioxin cannot be highly toxic since studies on octachlorodibenzo-p-dioxin containing several percent of heptachloro-dibenzo-p-dioxin have tested the same as the pure product. 

Chemical/Physical. TCDD was dehalogenated by a solution of poly (ethylene glycol), potassium carbonate, and sodium peroxide. After 2 h at 85 °C, >99.9% of the applied TCDD decomposed. Chemical intermediates identified include tri-, di-, and chloro[Ae]dibenzo[l,4]dioxin, di-benzodioxin, hydrogen, carbon monoxide, methane, ethylene, and acetylene (Tundo et al., 1985). TCDD will not hydrolyze to any reasonable extent (Kollig, 1993). 

Chloro[6,e]dibenzo[l,4]dioxin, see TCDD Chlorodibenzofuran, see Dibenzofuran 2-Chlorodibenzo[6,e][l,4]dioxin, see TCDD Chlorodibromonaphthalene, see Naphthalene 2-Chloro-2, 6 -diethylacetanilide, see Alachlor... 

A study of the soil of a Douglas fir forest in The Netherlands spiked with 37CI -chloride demonstrated that chlorinated phenols, dibenzo-p-dioxins, and dibenzo-furans are produced naturally in the humic soil layer probably via chloroperoxidase chemistry (Scheme 3.5) (1712). Twenty polychlorinated dioxins and furans were found to be produced naturally in this study, including the highly toxic 2,3,7,8-tetra- (2246), 1,2,3,7,8-penta- (2247), and 1,2,3,7,8,9-hexachlorodibenzo-p-dioxin (2248). The major congeners found are 4-chloro- (2249), 1,7-dichloro-... 

As discussed in the earlier survey (1), a biogenic source of polychlorinated dibenzo-p-dioxins and dibenzofurans is peroxidase-catalyzed transformation of chlorophenols as first reported by Oberg and Rappe (2041-2044). More recent studies confirm these observations (2045-2048). In addition to lactoperoxidase and horseradish peroxidase, human leukocyte myeloperoxidase catalyzes in vitro formation of dioxins and dibenzofurans from chlorophenols (2046, 2047). Formation rates are in the pmol/mol range (Scheme 3.6) demonstrating that a human biosynthesis of dioxins and furans is not only possible but also likely. These observations are reinforced by the reported in vivo (rats) conversion of the pre-dioxin nona-chloro-2-phenoxyphenol to octachlorodibenzo-p-dioxin (OCDD) (2049), and the production of hepta- and octachlorodibenzo-p-dioxin in the feces of cows fed pentachlorophenol-treated wood (Scheme 3.7) (2050, 2051). 

Buser HR (1976), J. Chromat. 129 303-307.. .Preparation of qualitative standard mixtures of polychlorinated dibenzo-p-dioxins and dibenzofurans by ultraviolet irradiation of the octa-chloro compounds"... 

A series of dibenzo[l,4]dioxins bearing nitro and trifluoromethyl substituents in one ring and chloro in the other was synthesized for comparison with impurities in commercial samples of the lampricide 3-trifluoromethyl-4-nitrophenol, and to assess their ability to induce MFO activity (Hewitt et al. 1998). 

R)-Spirobi-1,4-dioxan (212) has been prepared from 2-chloro-ethyl 3-D-fructopyranoside.220 A study of the half-chair conformations of compounds (213 X and Y = or S or S02 R1, R2=a variety of substituents or benzo) has been made using H n.m.r. spectros-copy,221 and the conformation of dibenzo-1,4-dioxin is folded about the 0-0 axis at an angle of 16S3 according to an n.m.r. study.222 Tetrachlorodibenzodioxin is a very stable compound but electrolysis in the presence of other oxidizable compounds breaks down the molecule.22 3... 

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