2-Pentanone

CAS RN:107-87-9

Environmental Fate

TERRESTRIAL FATE: Based on a classification scheme(1), an estimated Koc value of 75(SRC), determined from a log Kow of 0.91(2) and a regression-derived equation(3), indicates that 2-pentanone is expected to have high mobility in soil(SRC). Volatilization of 2-pentanone from moist soil surfaces is expected to be an important fate process(SRC) given a Henry's Law constant of 8.36X10-5 atm-cu m/mole(4). 2-Pentanone is expected to volatilize from dry soil surfaces(SRC) based upon a vapor pressure of 35.4 mm Hg(5). 2-Pentanone has been shown to biodegrade under aerobic conditions(6-8).

AQUATIC FATE: Based on a classification scheme(1), an estimated Koc value of 75(SRC), determined from a log Kow of 0.91(2) and a regression-derived equation(3), indicates that 2-pentanone is not expected to adsorb to suspended solids and sediment(SRC). Volatilization from water surfaces is expected(3) based upon a Henry's Law constant of 8.36X10-5 atm-cu m/mole(4). Using this Henry's Law constant and an estimation method(3), volatilization half-lives for a model river and model lake are 12 hours and 6.6 days, respectively(SRC). According to a classification scheme(5), an estimated BCF of 3(SRC), from its log Kow(2) and a regression-derived equation(6), suggests the potential for bioconcentration in aquatic organisms is low(SRC). 2-Pentanone is expected to biodegrade in water based on a screening test designed to simulate a polluted river, where the 5 day theoretical BOD for 2-pentanone was 43%(7).

ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), 2-pentanone, which has a vapor pressure of 35.4 mm Hg at 25 deg C(2), is expected to exist solely as a vapor in the ambient atmosphere. Vapor-phase 2-pentanone is degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals(SRC); the half-life for this reaction in air is estimated to be 3.5 days(SRC), calculated from its rate constant of 4.56X10-12 cu cm/molecule-sec at 25 deg C(3). 2-Pentanone contains chromophores that absorb at wavelengths >290 nm and therefore may be susceptible to direct photolysis by sunlight(4).

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