ABSTRACT

CASRN: 96-37-7; DOT: 2298; DOT label: Combustible liquid; molecular formula: C6H12; FW: 84.16; RTECS: GY4640000 Physical state, color, and odor: Colorless liquid with a sweetish odor. An odor threshold concentration of 1.7 ppmv was reported by Nagata and Takeuchi (1990). Melting point (°C): -142.4 (Weast, 1986) Boiling point (°C): 71.8 (Sinor and Weber, 1960) Density (g/cm3): 0.7486 at 20 °C (Kay, 1947) 0.7443 at 25 °C (Ehrett and Weber, 1959; Sinor and Weber, 1960) Diffusivity in water (x 10-5 cm2/sec): 0.85 at 20 °C (Witherspoon and Bonoli, 1969) 0.90 at 25 °C (Bonoli and Witherspoon, 1968) Dissociation constant, pKa: >14 (Schwarzenbach et al., 1993) Flash point (°C): <-7 (NFPA, 1984) Lower explosive limit (%): 1.0 (NFPA, 1984) Upper explosive limit (%): 8.35 (NFPA, 1984) Entropy of fusion (cal/mol⋅K): 12.67 (Domalski and Hearing, 1998) Heat of fusion (kcal/mol): 1.656 (quoted, Riddick et al., 1986) Henry’s law constant (atm⋅m3/mol): 0.362 at 25 °C (Hine and Mookerjee, 1975) Ionization potential (eV): 9.7 (Lias, 1998)

oc Unavailable because experimental methods for estimation of this parameter for alicyclic hydrocarbons are lacking in the documented literature Octanol/water partition coefficient, log Kow: 2.84 at 25.0 °C (shake flask-GLC, Park and Park, 2000) Solubility in organics: In methanol, g/L: 380 at 5 °C, 415 at 10 °C, 500 at 15 °C, 595 at 20 °C, 740 at 25 °C, 1,100 at 30 °C. Miscible at higher temperatures (Kiser et al., 1961). Solubility in water (mg/kg): 41.8 at 25 °C, 18.0 at 40.1 °C, 18.9 at 55.7 °C, 33.8 at 99.1 °C, 79.5 at 120.0 °C, 139.0 at 137.3 °C, 244.0 at 149.5 °C. In NaCl solution at 25 °C (salinity, g/kg): 38 (1.002), 36.3 (10.000), 29.2 (34.472), 27.0 (50.030), 12.7 (125.100), 5.72 (199.900), 3.36 (279.800), 1.89 (358.700) (shake flask-GLC, Price, 1976)

42 at 25 °C (shake flask-GC, McAuliffe, 1966) 42.6 at 25 °C (shake flask-GC, McAuliffe, 1963) Vapor density: 3.44 g/L at 25 °C, 2.91 (air = 1) Vapor pressure (mmHg): 125.1 at 24.75 °C (Willingham et al., 1945) 200 at 39.92 °C (Braun still-refractometry, Ehrett and Weber, 1959) Environmental fate: Photolytic. A photooxidation rate constant of 7.0 x 10-12 cm3/molecule⋅sec was reported for the reaction of methylcyclopentane and OH radicals in the atmosphere (Atkinson, 1990). Chemical/Physical. Complete combustion in air produces carbon dioxide and water vapor. Methylcyclopentane will not hydrolyze because it does not contain a hydrolyzable functional group. At elevated temperatures, rupture of the ring occurs and 1-propene is produced in a 40% yield. Other products include hydrogen and cyclic mono-and diolefins (Rice and Murphy, 1942). Symptoms of exposure: Vapors may irritate respiratory tract (Patnaik, 1992). Source: A constituent in gasoline. Harley et al. (2000) analyzed the headspace vapors of three grades of unleaded gasoline where ethanol was added to replace methyl tert-butyl ether. The gasoline vapor concentrations of methylcyclopentane in the headspace were 2.7 wt % for regular grade, 2.6 wt % for mid-grade, and 2.6 wt % for premium grade. California Phase II reformulated gasoline contained methylcyclopentane at a concentration of 26.2 g/kg. Gas-phase tailpipe emission rates from gasoline-powered automobiles with and without catalytic converters were 4.32 and 604 mg/km, respectively (Schauer et al., 2002). Uses: Extractive solvent; azeotropic distillation agent; organic synthesis.