ABSTRACT
CASRN: 540-84-1; DOT: 1262; DOT label: Flammable liquid; molecular formula: C8H18; FW: 114.23; RTECS: SA3320000; Merck Index: 12, 5210 Physical state, color, and odor: Colorless, flammable liquid with a gasoline-like odor. An odor threshold concentration of 670 ppbv was reported by Nagata and Takeuchi (1990). Melting point (°C): -107.4 (Weast, 1986) -116 (Sax and Lewis, 1987) Boiling point (°C): 99.35 (Martínez-Soria et al., 1999) Density (g/cm3): 0.68777 at 25 °C (Dreisbach, 1959) 0.69192 at 20.00 °C, 0.67538 at 30.00 °C (Hahn and Svejda, 1996) 0.6879 at 25.00 °C (Aralaguppi et al., 1999) 0.68762 at 25.00 °C (Bouzas et al., 2000) 0.67537 at 40.00 °C (Kalali et al., 1992) Diffusivity in water (x 10-5 cm2/sec): 0.66 at 20 °C using method of Hayduk and Laudie (1974) Dissociation constant, pKa: >14 (Schwarzenbach et al., 1993) Flash point (°C): -12 (Windholz et al., 1983) Lower explosive limit (%): 1.1 (Sax and Lewis, 1987) Upper explosive limit (%): 6.0 (Sax and Lewis, 1987) Entropy of fusion (cal/mol⋅K): 13.07 (Parks et al., 1930) Heat of fusion (kcal/mol): 2.161 (Parks et al., 1930) Henry’s law constant (atm⋅m3/mol): 3.23 at 25 °C (Mackay and Shiu, 1981)
50.1 at 25 °C (Demond and Lindner, 1993) Ionization potential (eV): 9.89 (Lias, 1998) Soil organic carbon/water partition coefficient, log Koc: Unavailable because experimental methods for estimation of this parameter for aliphatic hydrocarbons are lacking in the documented literature Octanol/water partition coefficient, log Kow: 5.83 (estimated using HPLC-MS, Burkhard et al., 1985a) Solubility in organics: In methanol, g/L: 249 at 5 °C, 279 at 10 °C, 314 at 15 °C, 353 at 20 °C, 402 at 25 °C, 460 at 30 °C, 560 at 35 °C, 760 at 40 °C (Kiser et al., 1961) Solubility in water: 1.14 mg/kg at 25 °C (shake flask-GLC, Price, 1976) 2.46 mg/kg at 0 °C, 2.05 mg/kg at 25 °C (shake flask-GC, Polak and Lu, 1973) 2.44 mg/kg at 25 °C (shake flask-GC, McAuliffe, 1963, 1966) 0.900 mL/L; 1.296 mL/L 0.1 wt % aqueous sodium naphthenate (Baker, 1980) Vapor density: 4.67 g/L at 25 °C, 3.94 (air = 1) Vapor pressure (mmHg): 47.8 at 24.4 °C (Willingham et al., 1945) 49.3 at 25 °C (Wilhoit and Zwolinski, 1971) 62.5 at 30.00 °C, 147.3 at 50 °C (Kalali et al., 1992) Environmental fate: Surface Water. Mackay and Wolkoff (1973) estimated an evaporation half-life of 4.1 sec from a surface water body that is 25 °C and 1 m deep. Photolytic. The following rate constants were reported for the reaction of 2,2,4-trimethylpentane and OH radicals in the atmosphere: 2.3 x 10-12 cm3/molecule⋅sec at 300 K (Hendry and Kenley, 1979); 2.83 x 10-12 cm3/molecule⋅sec at 298 K (Greiner, 1970); 3.73 x 10-12 cm3/molecule⋅sec at 298-305 K (Darnall et al., 1978); 3.7 x 10-12 cm3/molecule⋅sec (Atkinson et al., 1979); 3.90 x 10-12 cm3/molecule⋅sec at 298 K (Atkinson, 1985). Based on a photooxidation rate constant of 3.68 x 10-12 cm3/molecule⋅sec for the reaction of 2,2,4-trimethylpentane and OH radicals in summer sunlight, the lifetime is 16 h (Altshuller, 1991). Products identified from the reaction of 2,2,4-trimethylpentane with OH radicals in the presence of nitric oxide included acetone, 2-methypropanal, 4-hydroxy-4-methyl-2-pentanone, and hydroxy nitrates (Tuazon et al., 2002). Chemical/Physical. Complete combustion in air produces carbon dioxide and water vapor. 2,2,4-Trimethylpentane will not hydrolyze in water. Exposure limits: ACGIH TLV: TWA for all isomers 300 ppm (adopted). Symptoms of exposure: High concentrations may cause irritation of respiratory tract (Patnaik, 1992).
