Hexachloroethane, removal from

Hexachloroethane, removal from zirconium (IV) chloride, 4 124 Hexachloroplumbic(IV) acid, 1 48 Hexaguanidonium tetraphosphate 1-hydrate, 5 97, 100 Hexahalogenoplumbic acids, 1 48 Hexahalogenotellurates(IV), 2 188 Hexaiodostannates(IV), formation of, by tin(IV) iodide, 4 121 Hexametaphosphates (see Metaphosphates)... 

The primary metabolites of hexachloroethane are eventually oxidized to form trichloroethanol and trichloroacetic acid. These ultimate metabolites are excreted along with unchanged hexachloroethane, tetrachloroethene, and pentachloroethane. A small amount of the absorbed hexachloroethane is oxidized completely to carbon dioxide. Hexachloroethane and its metabolites are removed from the body in exhaled... 

Hexachloroethane released to water or soil may volatilize into air or adsorb onto soil and sediments. Volatilization appears to be the major removal mechanism for hexachloroethane in surface waters (Howard 1989). The volatilization rate from aquatic systems depends on specific conditions, including adsorption to sediments, temperature, agitation, and air flow rate. Volatilization is expected to be rapid from turbulent shallow water, with a half-life of about 70 hours in a 2 m deep water body (Spanggord et al. 1985). A volatilization half-life of 15 hours for hexachloroethane in a model river 1 m deep, flowing 1 m/sec with a wind speed of 3 m/sec was calculated (Howard 1989). Measured half-lives of 40.7 and 45 minutes for hexachloroethane volatilization from dilute solutions at 25 C in a beaker 6.5 cm deep, stirred at 200 rpm, were reported (Dilling 1977 Dilling et al. 1975). Removal of 90% of the hexachloroethane required more than 120 minutes (Dilling et al. 1975). The relationship of these laboratory data to volatilization rates from natural waters is not clear (Callahan et al. 1979). 

Two impurities are apparent in the product, iron (III) chloride and hexachloroethane. Both are more volatile than zirconium tetrachloride. Nevertheless, if both are to be removed from the product, considerable product inevitably sublimes beyond K. The amount of hexachloroethane impurity is roughly a function of temperature, since runs made at 450° yield virtually none, whereas if the furnace is allowed to go much above 500°, appreciable quantities are formed. The amount of iron (III) chloride impurity depends on the purity of starting materials. ... 

Hexachloroethane [67-72-1] has, like carbon tetrachloride [56-23-5], been used to remove Hver flukes from mminants. Also used are alben2adole, previously mentioned as a ben2imida2ole, and cHoxanide [144327-41-3], oxycho2anide [2277-92-1], or rafoxanide [22662-39-1]. Ciba s Ivomect is used for fluke control in Europe. 

Depending on the desired application, additional refining may be necessary. For demagging (removal of magnesium from the melt), hazardous substances such as chlorine and hexachloroethane are often used, which may produce dioxins and dibenzofurans. Other, less hazardous methods, such as adding chlorine salts, are available. 

The catalytic activity of cytochrome P450 is not restricted to oxidation. Under certain conditions, especially anaerobic conditions or with certain substrates, it can function as a reductase. For example, P450 can catalyze the reductive removal of halide from polyhalo-genated alkanes such as hexachloroethane or halothane (8,9). 

Amino-l-0 -o-ribofuranosyl)imidazole-4-carboxamide (5.16 g, 20 mmol) and hexachloroethane (40 g, 100 mmol) were added to a solution of raethanolic NaOMe (prepared from 7.8 g of metallic Na and 150 mL of MeOH), and the solution was heated to reflux for 3 h with stirring. Paper chromatography of this solution showed two spots which, on elution, corresponded spectrophotometrically to the starting AICA-riboside and inosine (I). HjO (100 mL) was added, the hexachloroethane was removed by filtration and the filtrate was neutralized to pH 7 by adding portionwise Amberlite IR-120 (IH form). The resin was removed by filtration and washed with ILO. The combined filtrate and washings were concentrated in vacuo to give a crystalline mass, which was rccrystallizcd (HjO) to afford a pure sample yield 3 g (51 %). 

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