Hexachlorobutadiene, oxidation

The model compound, frans-4-chloro-4-octene, was chosen because it possessed the —C1C=CH— group of polychloroprene, but without the repeating 1,5-diene structure of the polymer. The autoxidation was similar to that observed for polychloroprene, although no induction period was observed (cf. hexachlorobutadiene oxidation above). The evolution of HC1 was proportional to the square of the time, but the oxidation kinetics were approximated more closely by the equation... 

Hexachlorobutadiene L,G Biooxidation after reductive or oxidative biodechlorination... 

A very small portion of the absorbed hexachlorobutadiene is oxidized to carbon dioxide. This pathway can be saturated since an increase in the hexachlorobutadiene dose does not cause a corresponding increase in excretion of labeled carbon dioxide (Dekant et al. 1988b Payan et al. 1991 Reichert et al. 1985). 

Hexachlorobutadiene was first prepared in 1877 by the chlorination of hexyl oxide (lARC 1979). Commercial quantities of hexachlorobutadiene have never been produced in the United States. The primary source of hexachlorobutadiene found in the United States is inadvertent production as a waste by-product of the manufacture of certain chlorinated hydrocarbons, such as tetrachloroethylene, trichloroethylene, and carbon tetrachloride (ERA 1980 Yang 1988). In 1982, ERA reported an annual volume of about 28 million pounds of hexachlorobutadiene inadvertently produced as a waste by- product from this source (ERA 1982b HSDB 1993). Table 4-1 summarizes information on U.S. companies that reported the production, import, or use of hexachlorobutadiene in 1990 based on the Toxics Release Inventory TRI90 (1992). The TRI data should be used with caution since only certain types of facilities are required to report. This is not an exhaustive list. 

No data were located regarding the transformation and degradation of hexachlorobutadiene in air. Based on the monitoring data, the tropospheric half-life of hexachlorobutadiene was estimated by one author to be 1.6 years in the northern hemisphere (Class and Ballschmiter 1987). However, analogy to structurally similar compounds such as tetrachloroethylene indicates that the half-life of hexachlorobutadiene may be as short as 60 days, predominantly due to reactions with photochemically produced hydroxyl radicals and ozone (Atkinson 1987 Atkinson and Carter 1984). Oxidation constants of <10 and 6 (m hr) were estimated for reactions with singlet oxygen and peroxy radicals, respectively (Mabey et al. 1982). 

Metabolic activation. Although the kidney does not contain as much cytochromes P-450 as the liver, there is sufficient activity to be responsible for metabolic activation, and other oxidative enzymes such as those of the prostaglandin synthetase system are also present. Such metabolic activation may underlie the renal toxicity of chloroform and paracetamol (see chap. 7). Other enzymes such as C-S lyase and GSH transferase may also be involved in the activation of compounds such as hexachlorobutadiene (see chap. 7). In some cases, hepatic metabolism may be involved followed by transport to the kidney and subsequent toxicity. 

HEXACHLOROBUTADIENE or HEXACHLORO-l,3-BUTADIENE (87-68-3) C4C1 CliC=CClCCl=CCIj Combustible liquid (flash point 195°F/90°C autoignition temp 1125°F/607°C Fire Rating 1). Unless inhibited, may form unstable peroxides in storage. Reacts strongly with oxidizers, aliuninum powder may cause fire and explosion. Mixtures with bromine perchlorate forms heat-, friction-, and shock-sensitive explosive compound. Attacks aluminum, and some plastics and coatings decomposes rubber. Thermal decomposition releases toxic and irritating chloride fumes. On small fires, use dry... 

Detailed studies of the kinetics and mechanism of the oxidation of hexachlorobutadiene have been reported by Poluetov and Ageev [167,... 

Oxidation of the hexachlorobutadiene is interesting in that the halogen is involved in conjugation and can supply electrons to the pi system of the diene. Chlorine atoms are apparently not involved in the free radical chain and a peroxide-based reaction scheme has been proposed, viz. 

Hexachlorobutadiene added with stirring during 4 hrs. to a refluxing suspension of Zn-dust, Nal, and cupric chloride dideuteriate in deuterium oxide hexa-deuterio-1,3-butadiene. Y 80-85%. F. e. by catalytic replacement s. R.M. Warner and L. G. Leitch, J. Labelled Gompounds 1, 42 (1965). 

Chlorine is readily soluble in sulfiir-chlorine compounds, which can be used as industrial solvents for chlorine. Disulfiir dichloride U0025-67-9], S2CI2, is converted to sulfur dichloride (SCI2) and sulfiir tetrachloride (SCI4). Some metallic chlorides and oxide chlorides, such as vanadium oxide chloride, chromyl chloride, titanium tetrachloride, and tin(IV) chloride, are good solvents for chlorine. Many other chlorine-containing compounds dissolve chlorine readily. Examples are phosphoryl chloride, carbon tetrachloride (Fig. 7), tetrachloroethane, pentachloroethane, hexachlorobutadiene... 

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