Tetrachloroethylene oxide

Yoshioka T, JA Krauser, FP Guengerich (2002) Tetrachloroethylene oxide hydrolytic products and reactions with phosphate and lysine. Chem Res Toxicol 15 1096-1105. 

Two further compounds are briefly discussed here. Tetrachloroethylene administered to animals yielded 2,2,2-trichloroacetic acid (10.95, Fig. 10.23) as the only chlorinated metabolite [13]. These findings provided the first evidence that tetrachloroethylene is oxidized by cytochrome P450 to its epoxide (10.94), which rearranges by Cl migration to 2,2,2-trichloroacetyl chloride (Fig. 10.23). The latter hydrolyzes to 2,2,2-trichloroacetic acid (10.95), but also acylates tissue proteins, a reaction of unclear toxicological significance. In vitro investigations of tetrachloroethylene oxide (2,2,3,3-tetrachlo-rooxirane, 10.94) further showed that it hydrolyzes to the vicinal diol (10.96... 

Fig. 10.23. Simplified reactivity and metabolism of tetrachloroethylene oxide (10.94) and 1,3-dichloropropene oxide (10.97). In both cases, the conditions dictate the relative contributions of heterolytic oxirane opening with Cl migration and oxirane hydration followed by loss of...

Chloroacetyl chloride is manufactured by reaction of chloroacetic acid with chlorinating agents such as phosphoms oxychloride, phosphoms trichloride, sulfuryl chloride, or phosgene (42—44). Various catalysts have been used to promote the reaction. Chloroacetyl chloride is also produced by chlorination of acetyl chloride (45—47), the oxidation of 1,1-dichloroethene (48,49), and the addition of chlorine to ketene (50,51). Dichloroacetyl and trichloroacetyl chloride are produced by oxidation of trichloroethylene or tetrachloroethylene, respectively. 

Aerobic, Anaerobic, and Combined Systems. The vast majority of in situ bioremediations ate conducted under aerobic conditions because most organics can be degraded aerobically and more rapidly than under anaerobic conditions. Some synthetic chemicals are highly resistant to aerobic biodegradation, such as highly oxidized, chlorinated hydrocarbons and polynuclear aromatic hydrocarbons (PAHs). Examples of such compounds are tetrachloroethylene, TCE, benzo(a)pyrene [50-32-8] PCBs, and pesticides. 

The properties of 1,1-dichloroethane are Hsted ia Table 1. 1,1-Dichloroethane decomposes at 356—453°C by a homogeneous first-order dehydrochlofination, giving vinyl chloride and hydrogen chloride (1,2). Dehydrochlofination can also occur on activated alumina (3,4), magnesium sulfate, or potassium carbonate (5). Dehydrochlofination ia the presence of anhydrous aluminum chloride (6) proceeds readily. The 48-h accelerated oxidation test with 1,1-dichloroethane at reflux temperatures gives a 0.025% yield of hydrogen chloride as compared to 0.4% HCl for trichloroethylene and 0.6% HCl for tetrachloroethylene. Reaction with an amine gives low yields of chloride ion and the dimer 2,3-dichlorobutane, CH CHCICHCICH. 2-Methyl-l,3-dioxaindan [14046-39-0] can be prepared by a reaction of catechol [120-80-9] with 1,1-dichloroethane (7). 

Oxidation. 1,1,1-Trichloroethane is stable to oxidation when compared to olefinic chlorinated solvents like trichloroethylene and tetrachloroethylene. Use of a 48-h accelerated oxidation test gave no hydrogen chloride, whereas trichloroethylene gave 0.4 wt % HCl and tetrachloroethylene gave 0.6 wt % HCl (22). 

Physical properties of hexachloroethane are Hsted in Table 11. Hexachloroethane is thermally cracked in the gaseous phase at 400—500°C to give tetrachloroethylene, carbon tetrachloride, and chlorine (140). The thermal decomposition may occur by means of radical-chain mechanism involving -C,C1 -C1, or CCl radicals. The decomposition is inhibited by traces of nitric oxide. Powdered 2inc reacts violentiy with hexachloroethane in alcohoHc solutions to give the metal chloride and tetrachloroethylene aluminum gives a less violent reaction (141). Hexachloroethane is unreactive with aqueous alkali and acid at moderate temperatures. However, when heated with soHd caustic above 200°C or with alcohoHc alkaHs at 100°C, decomposition to oxaHc acid takes place. 

Exposure to tetrachloroethylene as a result of vapor inhalation is foUowed by absorption into the bloodstream. It is partly excreted unchanged by the lungs (17,18). Approximately 20% of the absorbed material is subsequently metabolized and eliminated through the kidneys (27—29). MetaboHc breakdown occurs by oxidation to trichloroacetic acid and oxaHc acid. 

Ethoxylation of the base alcohol always improves the solubility of the sulfate. As an example, sodium hexadecyl ether (2 EO) sulfate gives a clear 10% solution in water at 40°C, which becomes a viscous gel at 30°C [59]. Alcohol ether sulfates are also more soluble in organic solvents than the corresponding alcohol sulfates. Sodium hexadecyl and octadecyl ether (2 EO) sulfates are soluble at 1% concentration in lubricating oil, at 2.5% in benzene and chloroform, and at 5% in tetrachloroethylene, whereas alcohol-ethoxylated sulfates with 10 mol of ethylene oxide are soluble at 5% in lubricating oil [59]. 

Krumholz LR, R Sharp, SS Fishbain (1996) A freshwater anaerobe coupling acetate oxidation to tetrachloroethylene dehalogenation. Appl Environ Microbiol 62 4108-4113. 

The tetrachloroethylene/aluminium/zinc oxide mixture was used as a military flare . 

Oxidation of benzene to phenol. This was attempted in the former U.S.S.R. and Japan on a pilot-plant scale. High yields were reported, but full-scale operation apparently was discontinued because of destruction of product by irradiation and the possibility of explosion in the reaction vessel. The latter danger can be controlled in the oxidation of halo-genated hydrocarbons such as trichloro- or tetrachloroethylenes, where a chain reaction leads to the formation of dichloro- or trichloro-acetic acid chlorides through the respective oxides. 

For the decabromodiphenyl oxide (DBDPO) pyrolysis reactions, two different procedures were used to synthesize the series of brominated diphenyl oxides and dibenozofurans employed as the relative retention time standards AlBr3/Br2 in ethylene dibromide and Fe° (metal)/Br2 in tetrachloroethylene. The rate of the initial bromination steps in the former reaction was so rapid that only the higher degree of bromination adducts could be isolated. The rate of the Fe°/Br2 reaction was found to be much slower, especially during the initial stages, and these reactions yielded a broader range of relative retention time reference peaks. 

In batch kinetic tests, Yan and Schwartz (1999) investigated the oxidative treatment of chlorinated ethylenes in groundwater using potassium permanganate. 1,1-Dichloroethylene reacted more quickly than cis- and /ra/ 5-l, 2-dichloroethylene, trichloroethylene, and tetrachloroethylene. The reaction rate decreased with an increasing number of chlorine substituents. The pseudo-first-order rate constant and half-life for oxidative degradation (mineralization) of 1,1-dichloroethyene were 2.38 x 10 Vsec and 4.9 min, respectively. 

Note May contain acetone, aniline, 2-methylphenol, or ethyl acetate to prevent corrosion with aluminum, iron, and zinc. To prevent acid formation, stabilizers added to tetrachloroethylene may include tert-butylglycidyl ether, diallylamine, 2,3-epoxypropyl isopropyl ether, diisopropylamine, 4-methylmorpholine, diallylamine, tripropylene, cyclohexene oxide, and benzotriazole. 

Cyclohexene. 1 -Octene, Pentachlorophenol Cyclohexene, see Cyclohexanol, Methylene chloride 4 Cyclohexene-1,2-dicarboximide, see Captan Cyclohexene oxide, see Tetrachloroethylene... 

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). 

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