ABSTRACT
Note: Propylene oxide solutions may contain chloroacetone, 2,3-dichloro-1-propanol, and 1,2dichloropropane as impurities. CASRN: 75-56-9; DOT: 1280; DOT label: Flammable liquid; molecular formula: C3H6O; FW: 58.08; RTECS: TZ2975000; Merck Index: 12, 8041 Physical state, color, and odor: Clear, colorless liquid with an agreeable, ether-like odor. Experimentally determined detection and recognition odor threshold concentrations were 24 mg/m3 (10 ppmv) and 84 µg/m3 (35 ppmv), respectively (Hellman and Small, 1974). Melting point (°C): -113 (NIOSH, 1997) -104.4 (quoted, Verschueren, 1983) Boiling point (°C): 34.3 (Weast, 1986) Density (g/cm3): 0.859 at 0 °C (Weast, 1986) Flash point (°C): -35 (Windholz et al., 1983) Lower explosive limit (%): 2.8 (Sax and Lewis, 1987) 2.3 (NFPA, 1984) Upper explosive limit (%): 36 (NFPA, 1984) Entropy of fusion (cal/mol⋅K): 9.685 (Oetting, 1964) 9.737 (Beaumont et al., 1966) Heat of fusion (kcal/mol): 1.561 (Oetting, 1964) 1.570 (Beaumont et al., 1966) Henry’s law constant (atm⋅m3/mol): Not an environmentally important parameter because propylene oxide reacts rapidly with water Ionization potential (eV): 10.22 (Lias, 1998)
oc Not applicable - reacts with water Octanol/water partition coefficient, log Kow: 0.08 (Deneer et al., 1988) 0.03 (Hansch and Leo, 1987) Solubility in organics: Miscible with ether (Weast, 1986) and many alcohols including methanol, ethanol, propanol, and butanol. Solubility in water: 405,000 mg/L at 20 °C, 650,000 mg/L at 30 °C (quoted, Verschueren, 1983) 40 wt % at 20 °C (Gunther et al., 1968) Vapor density: 2.37 g/L at 25 °C, 2.01 (air = 1) Vapor pressure (mmHg): 416 at 19.0 °C, 574 at 27.0 °C, 806 at 36.3 °C, 950 at 40.8 °C, 1,157 at 46.8 °C, 1,265 at 50.2 °C,
1,452 at 54.0 °C, 1,694 at 59.2 °C, 1,994 at 64.7 °C, 2,403 at 71.8 °C (Bott and Sadler, 1966) Environmental fate: Biological. Bridié et al. (1979) reported BOD and COD values of 0.17 and 1.77 g/g using filtered effluent from a biological sanitary waste treatment plant. These values were determined using a standard dilution method at 20 °C for a 5 d period. When a sewage seed was used in a separate screening test, a BOD value of 0.20 g/g was obtained. The ThOD for propylene oxide is 2.21 g/g. Photolytic. Anticipated products from the reaction of propylene oxide with ozone or OH radicals in the atmosphere are formaldehyde, pyruvic acid, CH3C(O)OCHO, and HC(O)OCHO (Cupitt, 1980). An experimentally determined reaction rate constant of 5.2 x 10-13 cm3/molecule⋅sec was reported for the gas phase reaction of propylene oxide with OH radicals (Güsten et al., 1981). Chemical/Physical. The reported hydrolysis half-life for the conversion of propylene oxide to 1,2-propanediol in water at 25 °C and pH 7 is 14.6 d (Mabey and Mill, 1978). The second-order hydrolysis rate constant of propylene oxide in 3.98 mM perchloric acid and 36.3 °C is 0.124/M⋅sec (Kirkovsky et al., 1998). May polymerize at high temperatures or on contact with alkalies, aqueous acids, amines, and acid alcohols (NIOSH, 1997). At an influent concentration of 1.0 g/L, treatment with GAC resulted in an effluent concentration of 739 mg/L. The adsorbability of the GAC used was 52 mg/g carbon (Guisti et al., 1974). Exposure limits: Potential occupational carcinogen. NIOSH REL: IDLH 400 yes, mucous membranes, and skin. Inhalation may cause weakness and drowsiness (Patnaik, 1992). May cause blisters or burns (NIOSH, 1997). An irritation concentration of 1,125.00 mg/m3 in air was reported by Ruth (1986). Toxicity: LC50 (48-h) for Poecilia reticulata 32 mg/L (Deneer et al., 1988). LC50 (inhalation) for mice 1,740 ppm/4-h (quoted, RTECS, 1985).
