Propionitrile

CAS RN:107-12-0

Environmental Fate

TERRESTRIAL FATE: Based on a classification scheme(1), an estimated Koc value of 29(SRC), determined from an measured log Kow of 0.16(2) and a regression-derived equation(3), indicates that propionitrile is expected to have very high mobility in soil(SRC). Volatilization of propionitrile from moist soil surfaces is expected to be an important fate process(SRC) given a Henry's Law constant of 3.70X10-5 atm-cu m/mole(4). The potential for volatilization of propionitrile from dry soil surfaces may exist(SRC) based upon a vapor pressure of 47.4 mm Hg(5). Microorganisms hydrolyze nitriles predominately to carboxylic acids plus ammonium ions(6,7). A mixed microbial culture, isolated from an environment contaminated with organic cyanides and PCBs, utilized propionitrile as the sole source of carbon and nitrogen(8). Thus propionitrile may potentially biodegrade in soil(SRC).
AQUATIC FATE: Based on a classification scheme(1), an estimated Koc value of 29(SRC), determined from an measured log Kow of 0.16(2) and a regression-derived equation(3), indicates that propionitrile 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 3.70x10-5 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 13 hrs and 8 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). Microorganisms hydrolyze nitriles predominately to carboxylic acids plus ammonium ions(7,8). A variant of a yeast strain (Candiada famata) isolated from gold mine effluent was able to grow on propionitrile as the sole nitrogen source after acclimatization(9). In another study, a mixed microbial culture, isolated from an environment contaminated with organic cyanides and PCBs, utilized propionitrile as the sole source of carbon and nitrogen(10). The mixed microbial culture was grown for 48 hrs at pH 7 with 1 g/l of propionitrile; the final pH and ammonia concn were determined to be 8.66 and 75.9 umol/ml, respectively(10). Propionitrile was rapidly metabolized by activated sewage sludge to the amide(11).
ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), propionitrile, which has a vapor pressure of 47.4 mm Hg at 25 deg C(2), is expected to exist solely as a vapor in the ambient atmosphere(SRC). Vapor-phase propionitrile 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 83 days(SRC), calculated from its rate constant of 1.94X10-13 cu cm/molecule-sec at 25 deg C(3).
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