Toluene

CAS RN:108-88-3

Volatilization

The Henry's Law constant for toluene is 6.64X10-3 atm-cu m/mole(1). This Henry's Law constant indicates that toluene is expected to volatilize from water surfaces(2). Based on this Henry's Law constant, the volatilization half-life from a model river (1 m deep, flowing 1 m/sec, wind velocity of 3 m/sec)(2) is estimated as 2.9 hours(SRC). The volatilization half-life from a model lake (1 m deep, flowing 0.05 m/sec, wind velocity of 0.5 m/sec)(2) is estimated as 3.8 days(SRC). Toluene's Henry's Law constant indicates that volatilization from moist soil surfaces may occur(SRC). Toluene is expected to volatilize from dry soil surfaces(SRC) based upon a vapor pressure of 28.4 mm Hg(3). The air-water interface equilibrium partitioning coefficient for toluene, at a concentration of 0.47 mg/L, has been reported to be 0.223, 0.226, 0.273, and 0.336 at 26.9, 31.9, 36.9, and 41.9 deg C, respectively(4). A first-order volatilization rate calculated for toluene from water using an inverse reactive simulation was reported as 6.62X10-6/sec(5). The volatilization half-life of toluene from a water column of one meter depth was estimated to be 5.18 hours(6). Toluene was reported to have a disappearance half-life of <2 days due to volatilization in two different soil types, a Captina silt loam and a McLaurin sandy loam(7).
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