ABSTRACT
CASRN: 98-01-1; DOT: 1199; molecular formula: C5H4O2; FW: 96.09; RTECS: LT7000000; Merck Index: 12, 4324 Physical state, color, odor, and taste: Colorless to yellow liquid with an almond-like odor. Turns reddish brown on exposure to light and air. Odor and taste thresholds are 0.4 and 4 ppm, respectively (quoted, Keith and Walters, 1992). Shaw et al. (1970) reported a taste threshold in water of 80 ppm. Melting point (°C): -38.7 (Weast, 1986) Boiling point (°C): 161.7 (Weast, 1986) Density (g/cm3): 1.1594 at 20 °C (Weast, 1986) 1.1563 at 25 °C (Windholz et al., 1983) Diffusivity in water (x 10-5 cm2/sec): 1.12 at 25 °C (quoted, Hayduk and Laudie, 1974) Flash point (°C): 61 (NIOSH, 1997) 68 (open cup, Windholz et al., 1983) Lower explosive limit (%): 2.1 (NIOSH, 1997) Upper explosive limit (%): 19.3 (NIOSH, 1997) Henry’s law constant (x 10-6 atm⋅m3/mol): 1.52 at 20 °C (approximate - calculated from water solubility and vapor pressure) Interfacial tension with water (dyn/cm): 4.7 at 25 °C (Murphy et al., 1957; Demond and Lindner, 1993) Ionization potential (eV): 9.21 ± 0.01 (Franklin et al., 1969) Soil organic carbon/water partition coefficient, log Koc: Unavailable because experimental methods for estimation of this parameter for aldehydes are
to soil will be nominal (Lyman et al., 1982). Octanol/water partition coefficient, log Kow: 0.34 at 20.0 °C (shake flask, Korenman and Klyukvina, 1972) 0.41 (shake flask, Hansch and Leo, 1985) 0.52 at 25.0 °C (Tewari et al., 1981, 1982) Solubility in organics: Soluble in acetone, alcohol, benzene, chloroform, and ether (Weast, 1986) Solubility in water: 77.83 g/L at 25.0 °C (generator column-HPLC, Tewari et al., 1982; generator column-HPLC/GC,
Wasik et al., 1981) 92.9 g/L at 26.7 °C (Skrzec and Murphy, 1954) 82.0 g/L at 40 °C (Jones, 1929) In wt %: 8.22 at 0 °C, 7.86 at 10.0 °C, 7.94 at 20.0 °C, 8.40 at 30 °C, 8.94 at 40.0 °C, 9.50 at 50
°C, 10.28 at 60 °C, 10.97 at 70 °C, 12.56 at 80 °C, 14.74 at 90 °C (shake flask-GC, Stephenson, 1993c)
8.3 and 8.8 wt % at 25 and 35 °C, respectively (Heric et al., 1965) Vapor density: 3.93 g/L at 25 °C, 3.32 (air = 1) Vapor pressure (mmHg): 3 at 20.0 °C, 4 at 25.6 °C, 5 at 30.0 °C (Holdren and Hixon, 1946) Environmental fate: Biological. Under nitrate-reducing and methanogenic conditions, furfural biodegraded to methane and carbon dioxide (Knight et al., 1990). In activated sludge inoculum, following a 20-d adaptation period, 96.3% COD removal was achieved. The average rate of biodegradation was 37.0 mg COD/g⋅h (Pitter, 1976). Photolytic. Atkinson (1985) reported an estimated photooxidation half-life of 10.5 h for the reaction of furfural with OH radicals in the atmosphere. Chemical/Physical. Slowly resinifies at room temperature (Windholz et al., 1983). May polymerize on contact with strong acids or strong alkalies (NIOSH, 1997). Exposure limits: NIOSH REL: IDLH 100 ppm; OSHA PEL: TWA 5 ppm (20 mg/m3); ACGIH TLV: TWA 2 ppm (adopted). Toxicity: The acute inhalation LC50 dose reported for rats is approximately 182 ppm (Gupta et al., 1991). Acute oral LD50 for dogs 950 mg/kg, guinea pigs 541 mg/kg, mice 400 mg/kg, rats 65 mg/kg (quoted, RTECS, 1985). Source: Furfural occurs naturally in many plants including rice (90,000-100,000 ppm), lovage roots (2 to 20 ppm), caraway, strawberry leaves, cilantro, java cintronella, cassia, ylang-ylang, sweetflag, Japanese mint, oat husks (100,000 ppm), anise, broad-leaved lavender, myrtle flowers (0-1 ppm), lemon verbena, Karaya gum (123,000 ppm), nutmeg seeds (15,000 ppm), West Indian lemongrass, licorice roots (2 ppm), cinnamon bark (3 to 12 ppm), Hyssop shoots (1-2 ppm), periwinkle leaves, rockrose leaves, and garden dill (Duke, 1992).
