ABSTRACT
CH3 CASRN: 105-67-9; DOT: 2261; molecular formula: C8H10O; FW: 122.17; RTECS: ZE5600000; Merck Index: 12, 10215 Physical state and color: Colorless solid, slowly turning brown on exposure to air Melting point (°C): 24.5 (Andon et al., 1960) 27 (Dean, 1987) Boiling point (°C): 210 (Weast, 1986) 210-212 (Dean, 1987) Density (g/cm3 at 20 °C): 0.9650 (Weast, 1986) 1.02017 (Andon et al., 1960) Diffusivity in water (x 10-5 cm2/sec): 0.77 at 20 °C using method of Hayduk and Laudie (1974) Dissociation constant, pKa: 10.49 at 25 °C (Sprengling and Lewis, 1953) Flash point (°C): >110 (Aldrich, 1990) Henry’s law constant (x 10-6 atm⋅m3/mol): 8.29, 6.74, 10.1, 4.93, and 3.75 at 10, 15, 20, 25, and 30 °C, respectively (EPICS, Ashworth et al.,
1988) 1.50 at 20 °C (Sheikheldin et al., 2001) 42.8 at 75.9 °C, 74.0 at 88.7 °C, 113.0 at 98.5 °C (VLE circulation still-UV spectrophotometry,
Dohnal and Fenclová, 1995) Ionization potential (eV): 8.18 (Lias et al., 1998) Bioconcentration factor, log BCF: 1.18 (bluegill sunfish, Barrows et al., 1980) 2.18 (bluegill sunfish, Veith et al., 1980)
oc 2.08 (river sediment), 2.02 (coal wastewater sediment) (Kopinke et al., 1995) 2.19 (activated carbon, Blum et al., 1994) Octanol/water partition coefficient, log Kow: 2.54 at 35 °C (shake flask-UV spectrophotometry, Rogers and Wong, 1980) 2.42 at 23 °C (shake flask-LSC, Banerjee et al., 1980; Veith et al., 1980) 2.30 (Mabey et al., 1982) 2.42 (RP-HPLC, Garst and Wilson, 1984) 2.34 (generator column-HPLC/GC, Wasik et al., 1981) Solubility in organics: Freely soluble in ethanol, chloroform, ether, and benzene (U.S. EPA, 1985) Solubility in water: 7,868 mg/L at 25 °C (shake flask-LSC, Banerjee et al., 1980) 7,819 mg/L at 25.0 °C (generator column-HPLC/GC, Wasik et al., 1981) 8,795 mg/L at 25 °C and pH 5.1 (Blackman, 1955) 7,888 mg/L at 25 °C (Veith et al., 1980) In mg/kg: 34,786 at 10 °C, 35,648 at 20 °C, 37,549 at 30 °C (shake flask-nephelometry, Howe et
al., 1987) 8,200 mg/L at 25 °C (shake flask-HPLC/UV spectrophotometry, Varhaníčková et al., 1995a) Vapor pressure (x 10-2 mmHg): 6.21 at 20 °C (supercooled liquid, Andon et al., 1960) 9.8 at 25.0 °C (quoted, Leuenberger et al., 1985a) Environmental fate: Biological. When 2,4-dimethylphenol was statically incubated in the dark at 25 °C with yeast extract and settled domestic wastewater inoculum, significant biodegradation with rapid adaptation was observed. At concentrations of 5 and 10 mg/L, 100 and 99% biodegradation, respectively, were observed after 7 d (Tabak et al., 1981). Heukelekian and Rand (1955) reported a 5-d BOD value of 1.50 g/g which is 57.2% of the ThOD value of 2.62 g/g. In activated sludge inoculum, 94.5% COD removal was achieved in 5 d. The average rate of biodegradation was 28.2 mg COD/g⋅h (Pitter, 1976). Photolytic. 2,4-Dimethylphenol absorbs UV light at a maximum wavelength of 277 nm (Dohnal and Fenclová, 1995). Chemical/Physical. Wet oxidation of 2,4-dimethylphenol at 320 °C yielded formic and acetic acids (Randall and Knopp, 1980). 2,4-Dimethylphenol will not hydrolyze because there is no hydrolyzable functional group (Kollig, 1993). Toxicity: LC50 (contact) for earthworm (Eisenia fetida) 2.2 g/cm2 (Neuhauser et al., 1985). LC50 (8-d) for fathead minnows 13 to 14 mg/L (Spehar et al., 1982). LC50 (96-h) for bluegill sunfish 7.8 mg/L, fathead minnows 17 mg/L (Spehar et al., 1982). LC50 (48-h) for fathead minnows 9.5 mg/L (Spehar et al., 1982), Daphnia magna 2.1 mg/L (LeBlanc, 1980). LC50 (24-h) for Daphnia magna 8.3 mg/L (LeBlanc, 1980). Acute oral LD50 for mice 809 mg/kg, rats 3,200 mg/kg (quoted, RTECS, 1985). Source: Thomas and Delfino (1991) equilibrated contaminant-free groundwater collected from
24 h. The aqueous phase was analyzed for organic compounds via U.S. EPA approved test method 625. Average 2,4-dimethylphenol concentrations reported in water-soluble fractions of unleaded gasoline, kerosene, and diesel fuel were 50, 99, and 108 µg/L, respectively. 2,4-Dichlorophenol may also enter groundwater by leaching from coal tar, asphalt runoff, plastics, and pesticides (quoted, Verschueren, 1983). Uses: Wetting agent; dyestuffs; preparation of phenolic antioxidants; plastics, resins, solvent, disinfectant, pharmaceuticals, insecticides, fungicides, and rubber chemicals manufacturing; lubricant and gasoline additive; possibly used as a pesticide; plasticizers.
