1,1-DICHLOROETHYLENE

Cl Note: Hydroquinone monomethyl ether (0.02 wt %) is added to prevent polymerization (Gillette et al., 1952). CASRN: 75-35-4; DOT: 1303; DOT label: Combustible liquid; molecular formula: C2H2Cl2; FW: 96.94; RTECS: KV9275000; Merck Index: 12, 10134 Physical state, color, and odor: Colorless liquid or gas with a mild, sweet, chloroform-like odor. The average least detectable odor threshold concentration in water at 60 °C and in air at 40 °C was 1.6 mg/L (Alexander et al., 1982). Melting point (°C): -122.1 (Weast, 1986) Boiling point (°C): 31.56 (Boublik et al., 1986) Density (g/cm3 at 20 °C): 1.218 (Weast, 1986) 1.2132 (quoted, Riddick et al., 1986) Diffusivity in water (x 10-5 cm2/sec): 1.01 at 20 °C using method of Hayduk and Laudie (1974) Flash point (°C): -19 (NIOSH, 1997) Lower explosive limit (%): 6.5 (NFPA, 1984) Upper explosive limit (%): 15.5 (NFPA, 1984) Heat of fusion (kcal/mol): 1.557 (quoted, Riddick et al., 1986) Henry’s law constant (x 10-2 atm⋅m3/mol): 1.5 at 25 °C (gas stripping-GC, Warner et al., 1987) 19 (Pankow and Rosen, 1988) 2.56 at 25 °C (EPICS, Gossett, 1987) 1.54, 2.03, 2.18, 2.59, and 3.18 at 10, 15, 20, 25, and 30 °C, respectively (EPICS, Ashworth et al.,

1988) 2.29, 3.37, and 4.75 at 20, 30, and 40 °C, respectively (Tse et al., 1992)

0.86, 1.00, 1.27, 1.97, and 2.66 at 2.0, 6.0, 10.0, 18.0, and 25.0 °C, respectively (EPICS-SPME,

Dewulf et al., 1999) Ionization potential (eV): 9.81 ± 0.35 (Franklin et al., 1969) 9.46 (quoted, Horvath, 1982) 10.00 (NIOSH, 1997) Soil organic carbon/water partition coefficient, log Koc: 1.79 (Ellington et al., 1993) 2.47 (sewage solids, Dobbs et al., 1989) Octanol/water partition coefficient, log Kow: 2.13 (Mabey et al., 1982) Solubility in organics: Slightly soluble in ethanol, acetone, benzene, and chloroform (U.S. EPA, 1985) Solubility in water: 400 mg/L at 20 °C (Pearson and McConnell, 1975) In wt % (°C): 0.24 (15), 0.255 (17), 0.25 (20), 0.225 (25), 0.24 (28.5), 0.255 (29.5), 0.22 (38.5),

0.21 (45), 0.23 (51), 0.24 (60), 0.225 (65), 0.295 (71), 0.25 (74.5), 0.295 (81), 0.37 (85.5), 0.35 (90.5) (DeLassus and Schmidt, 1981)

2,232 mg/L at 30 °C (vapor equilibrium-GC, McNally and Grob, 1984) In mg/kg: 630 at 10 °C, 750 at 20 °C, 656 at 30 °C (shake flask-GC, Howe et al., 1987) Vapor density: 3.96 g/L at 25 °C, 3.35 (air = 1) Vapor pressure (mmHg): 591 at 25 °C, 720 at 30 °C (quoted, Verschueren, 1983) 495 at 20 °C, 760 at 31.8 °C (quoted, Standen, 1964) Environmental fate: Biological. 1,1-Dichloroethylene significantly degraded with rapid adaptation in a static-culture flask-screening test (settled domestic wastewater inoculum) conducted at 25 °C. Complete degradation was observed after 14 d. At concentrations of 5 and 10 mg/L, the amount lost due to volatilization at the end of 10 d was 24 and 15%, respectively (Tabak et al., 1981). Soil. In a methanogenic aquifer material, 1,1-dichloroethylene biodegraded to vinyl chloride (Wilson et al., 1986). Under anoxic conditions, indigenous microbes in uncontaminated sediments degraded 1,1-dichloroethylene to vinyl chloride (Barrio-Lage et al., 1986). Photolytic. Photooxidation of 1,1-dichloroethylene in the presence of nitrogen dioxide and air yielded phosgene, chloroacetyl chloride, formic acid, HCl, carbon monoxide, formaldehyde, and ozone (Gay et al., 1976). At 298 K, 1,1-dichloroethylene reacts with ozone at a rate of 3.7 x 10-21 cm3/molecule⋅sec (Hull et al., 1973). Chemical/Physical. At temperatures exceeding 0 °C in the presence of oxygen or other catalysts, 1,1-dichloroethylene will polymerize to a plastic (Windholz et al., 1983). The alkaline hydrolysis of 1,1-dichloroethylene yielded chloroacetylene. The reported hydrolysis half-life at 25 °C and pH 7 is 1.2 x 108 yr (Jeffers et al., 1989). The evaporation half-life of 1,1-dichloroethylene (1 mg/L) from water at 25 °C using a shallow-

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 trans-1,2-dichloroethylene, trichloroethylene, and tetrachloroethylene. The reaction rate decreased with an increasing number of chlorine substituents. The pseudo-firstorder rate constant and half-life for oxidative degradation (mineralization) of 1,1-dichloroethyene were 2.38 x 10-3/sec and 4.9 min, respectively. 1,1-Dichloroethylene reacts with OH radicals in the gas-phase. At 740 mmHg, the following rate constants were determined: 1.001 x 10-11 cm3/molecule·sec at 291 K, 9.84 x 10-12 cm3/molecule·sec at 292 K, and 8.71 x 10-12 cm3/molecule·sec at 340 K (Yamada et al., 2001). At influent concentrations of 1.0, 0.1, 0.01, and 0.001 mg/L, the GAC adsorption capacities at pH 5.3 were 4.9, 1.4, 0.41, and 0.12 mg/g, respectively (Dobbs and Cohen, 1980). Exposure limits: Potential occupational carcinogen. ACGIH TLV: TWA 5 ppm (adopted). Symptoms of exposure: Irritation of mucous membranes. Narcotic at high concentrations (Patnaik, 1992). Toxicity: EC10 and EC50 concentrations inhibiting the growth of alga Scenedesmus subspicatus in 96 h were 240 and 410 mg/L, respectively (Geyer et al., 1985). LC50 (96-h) for bluegill sunfish 74 mg/L, fathead minnows 108 mg/L (Spehar et al., 1982), Menidia beryllina 250 mg/L (quoted, Verschueren, 1983), Cyprinodon variegatus 250 ppm using natural seawater (Heitmuller et al., 1981). LC50 (72-h) for Cyprinodon variegatus 250 ppm (Heitmuller et al., 1981). LC50 (48-h) for Daphnia magna 79 mg/L (LeBlanc, 1980), Cyprinodon variegatus 250 ppm (Heitmuller et al., 1981). LC50 (24-h) for Daphnia magna 98 mg/L (LeBlanc, 1980), Cyprinodon variegatus 250 ppm (Heitmuller et al., 1981). LC50 (inhalation) for rats 6,350 ppm/4-h, mice 98 ppm/22-h (quoted, RTECS, 1985). Acute oral LD50 for rats 1,550 mg/kg, male mice 194 mg/kg, female mice 217 mg/kg (Jones and Hathway, 1978); dogs 5,750 mg/kg (Tierney et al., 1979). Heitmuller et al. (1981) reported a NOEC of 80 ppm. Drinking water standard (final): MCLG: 7 µg/L; MCL: 7 µg/L. In addition, a DWEL of 400 µg/L was recommended (U.S. EPA, 2000). Uses: Synthetic fibers and adhesives; chemical intermediate in vinylidene fluoride synthesis; production of poly(vinyl dichloroethylene) and 1,1,1-trichloroethane; comonomer for food packaging, coating resins, and modacrylic fibers.