ABSTRACT
CASRN: 589-81-1; molecular formula: C8H18; FW: 114.23 Physical state, color, and odor: Colorless, flammable liquid with an odor resembling hexane. An odor threshold concentration of 1.5 ppmv was reported by Nagata and Takeuchi (1990). Melting point (°C): -120.5 (Weast, 1986) Boiling point (°C): 118.00 (Cherqaoui and Villemin, 1994) 119 (Weast, 1986) Density (g/cm3): 0.70582 at 20 °C, 0.70175 at 25 °C (Dreisbach, 1959) Diffusivity in water (x 10-5 cm2/sec): 0.67 at 20 °C using method of Hayduk and Laudie (1974) Dissociation constant, pKa: >14 (Schwarzenbach et al., 1993) Heat of fusion (kcal/mol): 2.779 (Dean, 1987) Henry’s law constant (atm⋅m3/mol): 3.70 at 25 °C (approximate - calculated from water solubility and vapor pressure) 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: 3.97 using method of Hansch et al. (1968) Solubility in organics: In methanol, g/L: 154 at 5 °C, 170 at 10 °C, 190 at 15 °C, 212 at 20 °C, 242 at 25 °C, 274 at 30 °C, 314 at 35 °C, 365 at 40 °C (Kiser et al., 1961); miscible in many liquid hydrocarbons, particularly saturated hydrocarbons. Solubility in water: 792 µg/kg at 25 °C (shake flask-GLC, Price, 1976) Vapor density: 4.67 g/L at 25 °C, 3.94 (air = 1)
19.5 at 25 °C (Wilhoit and Zwolinski, 1971) 8.260 at 10.000 °C, 11.146 at 15.000 °C (inclined-piston, Osborn and Douslin, 1974) Environmental fate: Photolytic. Based on a photooxidation rate constant of 8.90 x 10-12 cm3/molecule⋅sec for the reaction of 3-methylheptane and OH radicals, the estimated lifetime is 16 h during summer sunlight (Altshuller, 1991). Chemical/Physical. Complete combustion in air produces carbon dioxide and water vapor. 3Methylheptane will not hydrolyze because it does not contain a hydrolyzable functional group. Uses: Calibration; gasoline component; organic synthesis.
