Propionic Anhydride

CAS RN: 123-62-6

Environmental Fate

TERRESTRIAL FATE: Hydrolysis half-lives of 10 and 1.0 minutes at pH values of 7 and 8, respectively, were estimated for propionic anhydride(1). Because of this rapid hydrolysis rate, biodegradation and volatilization from moist soil surfaces are not expected to be important terrestrial fate processes(SRC). Propionic anhydride is expected to volatilize from dry soil surfaces(SRC) based upon a vapor pressure of 1.36 mm Hg at 25 deg C(2).
AQUATIC FATE: Hydrolysis half-lives of 10 and 1.0 minutes at pH values of 7 and 8, respectively, were estimated for propionic anhydride(1). Because of this rapid hydrolysis rate, biodegradation, bioconcentration and volatilization from water surfaces are not expected to be important aquatic fate processes(SRC).
ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), propionic anhydride, which has a vapor pressure of 1.36 mm Hg at 25 deg C(2), is expected to exist solely as a vapor in the ambient atmosphere. Vapor-phase propionic anhydride 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 18 days(SRC), calculated from its rate constant of 9.1X10-13 cu cm/molecule-sec at 25 deg C(SRC) that was derived using a structure estimation method(3). Photolysis of propionic anhydride is not expected to be an important environmetnal fate process due to the rapid hydrolysis rate(SRC).
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