ABSTRACT
CASRN: 91-57-6; molecular formula: C11H10; FW: 142.20; RTECS: QJ9635000 Physical state: Solid Melting point (°C): 34.6 (Weast, 1986) Boiling point (°C): 241.052 (Wilhoit and Zwolinski, 1971) Density (g/cm3): 1.0058 at 20 °C (Weast, 1986) Diffusivity in water (x 10-5 cm2/sec): 0.72 at 20 °C using method of Hayduk and Laudie (1974) Dissociation constant, pKa: >15 (Christensen et al., 1975) Flash point (°C): 97 (Aldrich, 1990) Entropy of fusion (cal/mol⋅K): 9.38 (Tsonopoulos and Prausnitz, 1971) Heat of fusion (kcal/mol): 2.808 (Dean, 1987) 2.85 (Tsonopoulos and Prausnitz, 1971) Henry’s law constant (x 10-4 atm⋅m3/mol): 3.18 at 25 °C (wetted-wall column, Fendinger and Glotfelty, 1990) 4.54 at 25 °C (de Maagd et al., 1998) 2,000, 2,260, and 2,590 at 26.0, 35.8, and 46.0 °C, respectively (dynamic headspace, Hansen et al.,
1995) 1.28, 2.07, 3.28, 5.06, and 7.23 at 4.1, 11.0, 18.0, 25.0, and 31.0 °C, respectively (Bamford et al.,
1998) 6.13 at 25 °C (thermodynamic method-GC/UV spectrophotometry, Altschuh et al., 1999) Ionization potential (eV): 7.91 (Lias, 1998) Bioconcentration factor, log BCF: 3.79 (Davies and Dobbs, 1984)
oc 3.93 (Abdul et al., 1987) 3.40 (estuarine sediment, Vowles and Mantoura, 1987) 3.66 (Tinker), 3.23 (Carswell), 2.96 (Barksdale), 3.29 (Blytheville), 3.83 (Traverse City), 3.51
(Borden), 3.40 (Lula) (Stauffer et al., 1989) 3.00-5.96 based on 75 sediment determinations; average value = 4.56 (Hawthorne et al., 2006) Octanol/water partition coefficient, log Kow: 4.11 (Abdul et al., 1987) 3.86 (Hansch and Leo, 1979) 3.864 at 23 °C (shake flask-fluorometric, Krishnamurthy and Wasik, 1978) Solubility in organics: Soluble in most solvents (U.S. EPA, 1985). Solubility in water: 24.6 mg/kg at 25 °C (shake flask-GC, Eganhouse and Calder, 1976) 25.4 mg/L at 25 °C (shake flask-fluorescence, Mackay and Shiu, 1977) 1.53 mg/L (water soluble fraction of a 15-component simulated jet fuel mixture (JP-8) containing
6.3 wt % 2-methylnaphthalene (MacIntyre and deFur, 1985) 27.3 mg/L at 25 °C (generator column-HPLC, Vadas et al., 1991) Approximately 20.0 mg/L at 20 °C (air stripping-GC, Vozňáková et al., 1978) Vapor pressure (x 10-2 mmHg at 25 °C): 5.1 (calculated, Gherini et al., 1988) 5.4 (extrapolated, Mackay et al., 1982) Environmental fate: Biological. 2-Naphthoic acid was reported as the biooxidation product of 2-methylnaphthalene by Nocardia sp. in soil using n-hexadecane as the substrate (Keck et al., 1989). Dutta et al. (1998) investigated the degradation of 2-methylnaphthalene using a bacterial strain of Sphingomonas paucimobilis grown on phenanthrene. Degradation products identified using GC-MS were 4methylsalicylate, 2-methylnaphthoate, and 1-hydroxy-2-methylnaphthoate. Estimated half-lives of 2-methylnaphthalene (0.6 µg/L) from an experimental marine mesocosm during the spring (8-16 °C), summer (20-22 °C), and winter (3-7 °C) were 11, 1.0, and 13 d, respectively (Wakeham et al., 1983). Photolytic. Fukuda et al. (1988) studied the photodegradation of 2-methylnaphthalene and other alkylated naphthalenes in distilled water and artificial seawater using a high-pressure mercury lamp. Based upon an experimentally rate constant of 0.042/h, the photolytic half-life of 2methylnaphthalene in water is 16.4 h. Phousongphouang and Arey (2002) investigated gas-phase reaction of naphthalene with OH radicals in a 7-L Teflon chamber at 25 °C and 740 mmHg containing 5% humidity. The rate constant for this reaction was 4.86 x 10-11 cm3/molecule⋅sec. Chemical/Physical. An aqueous solution containing chlorine dioxide in the dark for 3.5 d at room temperature oxidized 2-methylnaphthalene into the following: 1-chloro-2-methylnaphthalene, 3-chloro-2-methylnaphthalene, 1,3-dichloro-2-methylnaphthalene, 3-hydroxymethylnaphthalene, 2-naphthaldehyde, 2-naphthoic acid, and 2-methyl-1,4-naphthoquinone (Taymaz et al., 1979). Toxicity: Acute oral LD50 for rats 1,630 mg/kg (quoted, RTECS, 1985).
