Chlorinated dibenzo-p-dioxins

Figure 5. Carbon-chlorine bond lengths (A) of chlorinated dibenzo-p-dioxins as a function of the number of chlorine substituents.

Studies were made on a series of chlorinated dibenzo-p-dioxin cation radicals in trifluoromethanesulfonic acid (TFMS acid). TFMS acid was... 

The visible absorption maxima for a series of chlorinated dibenzo-p-dioxins in TFMS acid are tabulated in Table I. The visible absorption spectra of these compounds vary with the position and number of chlorine atoms. In general, a bathochromic shift was observed as more chlorine atoms were attached to the dibenzo-p-dioxin nucleus. 

Variations in the manufacturing process of 2,4,5-trichloro- and pentachlorophenol (but not 2,4-dichlorophenol) have sometimes resulted in contamination of the product by small amounts of heterocyclic impurities (4,5). Of these, the chlorinated dibenzo-p-dioxins such as TCDD (2,3,7,8-tetrachlorodibenzo-p-dioxin) have received much scientific and public attention because of their real or potential toxicity 6, 7), [Chick edema factor, a curious toxicological problem to poultry producers for several years, has been shown to be composed of chlorodibenzo-p-dioxins (8).]... 

Figure 1. Photolysis rates of chlorinated dibenzo-p-dioxins in methanol under ultraviolet light 2J-dichlorodibenzo-p-dioxin (III) (5 mg/liter), 2,3,7,8-tetrachlorodiben-zo-p-dioxin (I) (5 mg/liter), 1,2,3,4,6,7,8,9-octachlorodibenzo-p-dioxin (IV) (2.2 mg/ liter) (20), 1971 by AAAS...

This paper discusses the effects of the pyrolysis of wood and paper treated with pentachlorophenol or sodium pentachlorophenate along with the exposure of sodium pentachlorophenate to ultraviolet light. The effect of heat, light, and air with respect to some of the chlorinated dibenzo-p-dioxins will be considered. 

Light Stability of Chlorinated Dibenzo-l -dioxins. A known concentration of chlorinated dibenzo-p-dioxin was placed in a quartz 1-cm path length cell. A General Electric R.S. sunlamp was placed either 0.5 or 1.0 meters from the face of the cell. The stability of the chlorinated dibenzo-p-dioxin was monitored using ultraviolet spectroscopy. 

In addition to its extremely high oral toxicity, skin contact with substances containing 2,3,7,8-tetrachlorodibenzo-p-dioxin may allow toxicity in the form of chloracne, a condition characterized by eruptions of the skin on the face, neck, and back. Also, chlorinated dibenzo-p-dioxins have been associated with the chick edema factor, a disease of chicks associated with contaminated fats or oils used in the manufacture of their feed. 

Higher chlorinated dibenzo-p-dioxins, such as the octachloro derivative, can be formed in manufacturing pentachlorophenol from hexachloro-... 

This volume should do much to advance the knowledge of these types of molecules, and additional research should be stimulated to explain further the chemical, physical, and biological properties of the chlorinated dibenzo-p-dioxins. 

Adriaens P, Q Fu, D Grbic-Galic (1995) Bioavailability and transformation of highly chlorinated dibenzo-p-dioxins and dibenzofurans in anaerobic soils and sediments. Environ Sci Technol 29 2252-2260. 

Shiu, W.-Y., Doucette, W., Gobas, F. A. P. C., Mackay, D., Andren, A. W. (1988) Physical-chemical properties of chlorinated dibenzo-p-dioxins. Environ. Sci. Technol. 22, 651-658. 

U.S. Public Health Service (USPHS). 1998. Toxicological profile for chlorinated dibenzo-p-dioxins (update). U.S. Dept. Health Human Serv., Agen. Toxic Subst. Dis. Regis. 709 pp. 

Lamparski, L.L., R.H. Stehl, and R.L. Johnson. 1980. Photolysis of pentachlorophenol-treated wood. Chlorinated dibenzo-p-dioxin formation. Environ. Sci. Technol. 14 196-200. 

Ryan, J.J., R. Lizotte, T. Sakuma, and B. Mori. 1985. Chlorinated dibenzo-p-dioxins, chlorinated dibenzo-furans, and pentachlorophenol in Canadian chicken and pork samples. Jour. Agric. Food Chem. 33 1021-1026. 

One approach, which has been used extensively in pharmacological areas [27], is to look for characteristic patterns of positive and negative regions that may enhance or inhibit a certain type of activity. The early stages of chug-receptor and enzyme-substrate interactions, in which the participants recognize each other through their outer electrostatic potentials, can be analyzed in this manner [28]. We were able, on this basis, to find qualitative trends in the toxicities of chlorinated dibenzo-p-dioxins and related systems [29]. 

Chlorinated dibenzo-p-dioxins and dibenzofurans are among the most toxic substances known, especially 2,3,7,8-tetrachloro-p-dibenzodioxin (TCDD). These extremely hazardous compounds can be produced from 3,4,5- and 2,4,5-trichlorophenols by peroxidases [207]. However, the biological formation of such toxicants in nature or by microorganisms has not been described. 

When exposed to fire, black soot containing PCBs, polychlorinated dibenzofurans, and chlorinated dibenzo-p-dioxins is formed (NIOSH, 1997). 

Chlordene chlorohydrin, see Chlordane Chlordene epoxide, see Heptachlor Chlorinated dibenzo-p-dioxin, see Pentachlorophenol Chlorinated dibenzo-p-dioxins, see PCB-1242, PCB-1254... 

Crummett, W.B. and Stehl, R.H. Determination of chlorinated dibenzo-p-dioxins and dibenzofurans in various materials. Environ. HealthPerspect, 5 15-25, 1973. 

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