ABSTRACT
Cl CASRN: 76-01-7; DOT: 1669; DOT label: Poison; molecular formula: C2HCl5; FW: 202.28; RTECS: KI6300000; Merck Index: 12, 7241 Physical state, color, and odor: Clear, colorless liquid with a sweetish, chloroform-like odor Melting point (°C): -29.0 (quoted, Horvath, 1982) Boiling point (°C): 159.72 (Boublik et al., 1973) 160.5 (Dean, 1987) Density (g/cm3): 1.6796 at 20 °C (Weast, 1986) 1.6808 at 20 °C, 1.6732 at 25 °C (quoted, Riddick et al., 1986) Diffusivity in water (x 10-5 cm2/sec): 0.79 at 20 °C using method of Hayduk and Laudie (1974) Heat of fusion (kcal/mol): 2.7 (Dean, 1987) Henry’s law constant (x 10-3 atm⋅m3/mol): 2.11 at 30 °C (headspace-GC, Sanz et al., 1997) Ionization potential (eV): 11.0, 11.28 (Lias et al., 1998) Bioconcentration factor, log BCF: 1.83 (bluegill sunfish, Veith et al., 1980) Soil organic carbon/water partition coefficient, log Koc: 3.28 (quoted, Mercer et al., 1990) Octanol/water partition coefficient, log Kow: 2.89 (Veith et al., 1980) Solubility in organics: Miscible with alcohol and ether (Windholz et al., 1983) Solubility in water: 3.8 mM at 20 °C (Veith et al., 1980)
2 500 mg/kg at 25 °C (McGovern, 1943) 500 and 769 mg/L at 20 and 25 °C, respectively (shake flask-fluorescence, Mackay and Shiu,
1981) Vapor density: 8.27 g/L at 25 °C, 6.98 (air = 1) Vapor pressure (mmHg): 3.4 at 20 °C, 6 at 30 °C (quoted, Verschueren, 1983) 4.5 at 25 °C (Mackay and Shiu, 1981) Environmental fate: Chemical/Physical. At various pHs, pentachloroethane hydrolyzed to tetrachloroethylene (Jeffers et al., 1989; Roberts and Gschwend, 1991). Dichloroacetic acid was also reported as a hydrolysis product. Reacts with alkalies and metals producing explosive chloroacetylenes (NIOSH, 1997). The reported hydrolysis half-life at 25 °C and pH 7 is 3.6 d (Jeffers et al., 1989). In anoxic hypolimnion samples collected from Lower Mystic Lake, MA, pentachloroethane was abiotically transformed within days to tetrachloroethylene via dehydrohalogenation pathway and to trichloroethylene via reductive elimination. After 10 d, mass balances of 91 and 86% were reported for unaltered and filter-sterilized samples, respectively. A disappearance rate constant of 0.26/d was reported for pentachloroethane for both the unaltered and filter-sterilized samples. The disappearance of pentachloroethane was abiotic in origin due to the reactions with naturally occurring aqueous polysulfides, H2S and Sn-2 (Miller et al., 1998a). The evaporation half-life of pentachloroethane (1 mg/L) from water at 25 °C using a shallowpitch propeller stirrer at 200 rpm at an average depth of 6.5 cm was 46.5 min (Dilling, 1977). Toxicity: EC50 (48-h) for Pseudokirchneriella subcapitata 7.22 mg/L (Hsieh et al., 2006). LC50 (7-d) for Poecilia reticulata 15 mg/L (Könemann, 1981). LC50 (96-h) for fathead minnows 7.3 mg/L (Veith et al., 1983), bluegill sunfish 7.2 mg/L (Spehar et al., 1982). LC50 (48 and 24-h) for Daphnia magna 63 mg/L (LeBlanc, 1980). Drinking water standard: No MCLGs or MCLs have been proposed (U.S. EPA, 1996). Uses: Solvent for chemicals, resins, gums; removing oil and grease from metal parts; dry cleaning agent; timber drying agent; fumigant.
