ABSTRACT
CASRN: 463-82-1; DOT: 2044; molecular formula: C5H12; FW: 72.15; RTECS: TY1190000; Merck Index: 12, 6545 Physical state: Colorless, extremely flammable gas which may have a faint, pleasant odor similar to butane. Usually present as a compressed gas or liquid. Melting point (°C): -16.5 (Weast, 1986) -19.8 (Windholz et al., 1983) Boiling point (°C): 9.5 (Weast, 1986) Density (g/cm3): 0.591 at 20 °C, 0.5852 at 25 °C (Dreisbach, 1959) Diffusivity in water (x 10-5 cm2/sec): 0.80 at 20 °C using method of Hayduk and Laudie (1974) Dissociation constant, pKa: >14 (Schwarzenbach et al., 1993) Flash point (°C): -65.0 (Hawley, 1981) Lower explosive limit (%): 1.4 (NFPA, 1984) Upper explosive limit (%): 7.5 (NFPA, 1984) Heat of fusion (kcal/mol): 0.752 (Dean, 1987) Henry’s law constant (atm⋅m3/mol): 3.70 at 25 °C (Mackay and Shiu, 1981) Ionization potential (eV): 10.35 (Franklin et al., 1969) 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
ow 3.11 (Hansch and Leo, 1979) Solubility in organics: Soluble in alcohol and ether (Weast, 1986). Solubility in water: 33.2 mg/kg at 25 °C (shake flask-GC, McAuliffe, 1966) Vapor density: 2.95 g/L at 25 °C, 2.49 (air = 1) Vapor pressure (mmHg): 1,287 at 25 °C (Wilhoit and Zwolinski, 1971) 1,074.43 at 19.492 °C, 1,267.75 at 24.560 °C (ebulliometry, Osborn and Douslin, 1974) Environmental fate: Photolytic. A rate constant of 6.50 x 10-11 cm3/molecule⋅sec was reported for the reaction of 2,2dimethylpropane with OH radicals in air at 298 (Greiner, 1970). Rate constants of 9.0 x 10-13 and 8.49 x 10-13 cm3/molecule⋅sec were reported for the reaction of 2,2-dimethylpropane with OH in air (Atkinson et al., 1979; Winer et al., 1979). Chemical/Physical. Complete combustion in air yields carbon dioxide and water vapor. 2,2Dimethylpropane will not hydrolyze because it has no hydrolyzable functional group. Exposure limits: ACGIH TLV: TWA 600 ppm (adopted). Toxicity: Acute oral LD50 (intraperitoneal) for mice 100 mg/kg (quoted, RTECS, 1985). Source: California Phase II reformulated gasoline contained 2,2-dimethylpropane at a concentration of 110 µg/kg (Schauer et al., 2002). Uses: Butyl rubber; organic synthesis.
