ABSTRACT
CASRN: 565-75-3; molecular formula: C8H18; FW: 114.23 Physical state, color, and odor: Clear, colorless, flammable, watery liquid with a mild aliphatic hydrocarbon odor resembling hexane. Melting point (°C): -109.2 (Weast, 1986) Boiling point (°C): 113.4 (Weast, 1986) Density (g/cm3): 0.71906 at 20 °C, 0.71503 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) Entropy of fusion (cal/mol⋅K): 13.54 (Pitzer and Scott, 1941) Heat of fusion (kcal/mol): 2.215 (Pitzer and Scott, 1941) Henry’s law constant (atm⋅m3/mol): 1.89 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: 3.78 using method of Hansch et al. (1968) Solubility in organics: Soluble in acetone, alcohol, benzene, chloroform, ether (Weast, 1986); miscible with many aliphatic hydrocarbons Solubility in water (mg/kg): 1.36 at 25 °C (shake flask-GLC, Price, 1976) 2.34 at 0 °C, 2.30 at 25 °C (shake flask-GC, Polak and Lu, 1973)
4.67 g/L at 25 °C, 3.94 (air = 1) Vapor pressure (mmHg): 27.0 at 25 °C (Wilhoit and Zwolinski, 1971) Environmental fate: Photolytic. Atkinson (1990) reported a rate constant of 7.0 x 10-12 cm3/molecule⋅sec for the reaction of 2,3,4-trimethylpentane and OH radicals in the atmosphere at 298 K. Based on this reaction rate constant, the estimated lifetime is 20 h (Altshuller, 1991). Chemical/Physical. Complete combustion in air produces carbon dioxide and water vapor. 2,3,4-Trimethylpentane will not hydrolyze because it does not contain a hydrolyzable functional group. Exposure limits: ACGIH TLV: TWA for all isomers 300 ppm (adopted). Source: Schauer et al. (1999) reported 2,3,4-trimethylpentane in a diesel-powered medium-duty truck exhaust at an emission rate of 310 µg/km. California Phase II reformulated gasoline contained 2,3,4-trimethylpentane at a concentration of 13.0 g/kg. Gas-phase tailpipe emission rates from gasoline-powered automobiles with and without catalytic converters were 2.51 and 412 mg/km, respectively (Schauer et al., 2002). Uses: Organic synthesis.
