Methyl isobutyl ketone

CAS RN: 108-10-1

Environmental Fate

TERRESTRIAL FATE: Based on a classification scheme(1), an estimated Koc value of 70(SRC), determined from a log Kow of 1.31(2) and a regression-derived equation(3), indicates that methyl isobutyl ketone is expected to have high mobility in soil(SRC). Volatilization of methyl isobutyl ketone from moist soil surfaces is expected to be an important fate process(SRC) given an estimated Henry's Law constant of 1.4X10-4 atm-cu m/mole(SRC) derived from its vapor pressure, 19.9 mm Hg(4), and water solubility, 19,000 mg/L(5). Methyl isobutyl ketone is expected to volatilize from dry soil surfaces(SRC) based upon its vapor pressure(4). An 84% of theoretical BOD using activated sludge in the Japanese MITI test(6) suggests that biodegradation is an important environmental fate process in soil(SRC).
AQUATIC FATE: Based on a classification scheme(1), an estimated Koc value of 70(SRC), determined from a log Kow of 1.31(2) and a regression-derived equation(3), indicates that methyl isobutyl ketone is not expected to adsorb to suspended solids and sediment(SRC). Volatilization from water surfaces is expected(3) based upon an estimated Henry's Law constant of 1.4X10-4 atm-cu m/mole(SRC), derived from its vapor pressure, 19.9 mm Hg(4), and water solubility, 19,000 mg/L(5). Using this Henry's Law constant and an estimation method(3), volatilization half-lives for a model river and model lake are 9 hours and 6 days, respectively(SRC). According to a classification scheme(6), an estimated BCF of 3(SRC), from its log Kow(2) and a regression-derived equation(7), suggests the potential for bioconcentration in aquatic organisms is low(SRC). An 84% of theoretical BOD using activated sludge in the Japanese MITI test(8) suggests that biodegradation is an important environmental fate process in water(SRC).
ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), methyl isobutyl ketone, which has a vapor pressure of 19.9 mm Hg at 25 deg C(2), is expected to exist solely as a vapor in the ambient atmosphere. Vapor-phase methyl isobutyl ketone 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 30(SRC), calculated from its rate constant of 1.3X10-11 cu cm/molecule-sec at 25 deg C(3). Methyl isobutyl ketone absorbs UV at wavelengths >290 nm(3) and, therefore, may be susceptible to direct photolysis by sunlight(SRC).
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