Hexachloroethane physical properties

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. 

Despite wearing protective equipment that included disposable overalls and compressed-air-fed visors or full-facepiece masks with filters for dusts and vapors, hexachloroethane was detected in the plasma of exposed workers (Selden et al. 1993). After 5 weeks of exposure, plasma levels of hexachloroethane in 12 workers were 7.3 + 6 pg/L. Mild dermal irritation was also noted. If the skin irritation was a response to hexachloroethane rather than trauma from the protective clothing, the irritation suggests that the principal exposure route may have been dermal. Absorption of a saturated hexachloroethane solution across human skin was estimated to be 0.0230 mg/cm2/hour based on the physical properties of hexachloroethane (Fiserova-Bergerova et al. 1990). 

This suggests poor dermal absorption of hexachloroethane and agrees with a calculated low dermal absorption rate of 0.023 mg/cm2/hr based on physical properties (Fiserova-Bergerova et al. 1990). 

Hexachloroethane caused reversible corneal injury in rabbits following ocular contact, but contact with the skin for 24 hours resulted in no dermal effects (Weeks et al. 1979). The physical properties of hexachloroethane suggest that absorption across human skin would be limited (Fiserova-Bergerova et al. 1990). Therefore, unless dermal absorption studies indicate that this prediction is incorrect, there is no need for additional studies of acute dermal toxicity. 

Hexachlorocyclotriphosphazene, 19 55 Hexachloroethane, 6 269 Hexachloromelamine, 23 111 Hexachlorophene, bioremediation substrate, 3 773-776 Hexachlorotitanates, 25 53 Hexacosanoic acid, physical properties, 5 30t... 

These experts collectively have knowledge of hexachloroethane s physical and chemical properties, toxicokinetics, key health end points, mechanisms of action, human and animal exposure, and quantification of risk to humans. All reviewers were selected in conformity with the conditions for peer review specified in Section 104(I)(13) of the Comprehensive Environmental Response, Compensation, and Liability Act, as amended. 

Table 3-2 lists important physical and chemical properties of hexachloroethane. 

Physical and Chemical Properties. The physical and chemical properties of hexachloroethane are sufficiently well characterized to allow estimation of its environmental fate (see Table 3-2) (EPA 1991a Spanggord et al. 1985 Verschueren 1983 Weast 1986). On this basis, it does not appear that further research in this area is required at this time. 

The physical integrity of a pyrotechnic formulation may, exceptionally, be threatened by evaporation. This can occur when a rather volatile compound is a necessary component because of unique properties that make it difficult or impossible to replace it with a more stable ingredient. Two such compounds have been described earlier One is metaldehyde of a sublimation point of about 112 C and found only in novelty items such as repeatedly ignitible matches, hence of little concern in commercial practice the other is the HC smoke ingredient hexachloroethane. Its vapor pressure, as eviden d by the odor at room temperature, is sufficient to cause concern. In practice, however, with tightly compressed and sealed mixtures in substantial units, the volatility of HC seems to cause no trouble. 

---