ABSTRACT

CASRN: 3522-94-9; molecular formula: C9H20; FW: 128.26 Physical state, color, and odor: Clear, colorless, flammable liquid with a faint aliphatic hydrocarbon odor. An odor threshold concentration of 900 ppbv was reported by Nagata and Takeuchi (1990). Melting point (°C): -105.8 (Weast, 1986) Boiling point (°C): 124 (Weast, 1986) Density (g/cm3): 0.70721 at 20 °C, 0.70322 at 25 °C (Dreisbach, 1959) Diffusivity in water (x 10-5 cm2/sec): 0.62 at 20 °C using method of Hayduk and Laudie (1974) Dissociation constant, pKa: >14 (Schwarzenbach et al., 1993) Flash point (°C): 12.7 (Hawley, 1981) Heat of fusion (kcal/mol): 1.48 (quoted, Riddick et al., 1986) Henry’s law constant (atm⋅m3/mol): 3.45 at 25 °C (Mackay and Shiu, 1981) 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: 3.88 using method of Hansch et al. (1968) Solubility in organics: In methanol, g/L: 162 at 5 °C, 179 at 10 °C, 200 at 15 °C, 221 at 20 °C, 247 at 25 °C, 280 at 30 °C, 316 at 35 °C, 360 at 40 °C (Kiser et al., 1961); miscible with hexane and pentane. Solubility in water (mg/kg): 0.79 at 0 °C, 0.54 at 25 °C (shake flask-GC, Polak and Lu, 1973) 1.15 at 25 °C (shake flask-GC, McAuliffe, 1966)

5.24 g/L at 25 °C, 4.43 (air = 1) Vapor pressure (mmHg): 3.647 at 0.000 °C, 5.072 at 5.000 °C, 6.958 at 10.000 °C, 9.418 at 15.000 °C, 12.583 at 20.000 °C, 16.625 at 25.000 °C, 21.719 at 30.000 °C (inclined-piston, Osborn and Douslin, 1974) Environmental fate: Chemical/Physical. Complete combustion in air produces carbon dioxide and water vapor. 2,2,5-Trimethylhexane will not hydrolyze because it does not contain a hydrolyzable functional group. Exposure limits: ACGIH TLV: TWA for all isomers 200 ppm (adopted). Uses: Motor fuel additive; organic synthesis.