Pentadecylbenzene

The log Koc of n-pentadecylbenzene is estimated as 6.5(SRC), using an estimated log Kow of 9.42(1,SRC) and a regression-derived equation(2). According to a classification scheme(3), this estimated log Koc value suggests that n-pentadecylbenzene is expected to be immobile in soil.

The BCF of n-pentyldecylbenzene was estimated as 3(SRC) from an estimated log Kow of 9.42(1,SRC) and a regression derived equation(2). The BCF value of bluegill sunfish exposed to dodecylbenzene in a flowing aquarium was 35(3). By analogy, the BCF value for n-pentadecylbenzene is expected to be similar(SRC). According to a classification scheme(4), these BCF vales suggest bioconcentration in aquatic organisms is moderate.

The Henry's Law constant for n-pentadecylbenzene is estimated as 0.79 atm-cu m/mole(SRC) using a fragment constant estimation method(1). This Henry's Law constant indicates that n-pentadecylbenzene is expected to volatilize rapidly from water surfaces(2), however adsorption may severely attenuate this process(SRC). 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 5 hours if adsorption is neglected(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 7 days if adsorption is neglected(SRC). The estimated volatilization half-life from a model pond is 70 years if adsorption is considered(3). n-Pentadecylbenzene's Henry's Law constant(1) indicates that volatilization from moist soil surfaces may occur, however adsorption may attenuate this process(SRC). n-Pentadecylbenzene is not expected to volatilize from dry soil surfaces(SRC) based upon a vapor pressure of 7.2X10-6 mm Hg at 25 °C(4).

The rate constant for the vapor-phase reaction of n-pentadecylbenzene with photochemically-produced hydroxyl radicals has been estimated as 2.4X10-11 cu cm/molecule-sec at 25 °C(SRC) using a structure estimation method(1). This corresponds to an atmospheric half-life of about 16 hours at an atmospheric concentration of 5X10+5 hydroxyl radicals per cu cm(1). n-Pentadecylbenzene is not expected to undergo hydrolysis in the environment due to the lack of hydrolyzable functional groups(2).

Occupational exposure to n-pentadecylbenzene may occur through inhalation and dermal contact with this compound at workplaces where n-pentadecylbenzene is produced or used. The general population may be exposed to n-pentadecylbenzene via dermal contact with this compound and consumer products containing n-pentadecylbenzene. (SRC)

n-Pentadecylbenzene's production and use as a component for detergents and a starting material for linear alkylsulfonates may result in its release to the environment through various waste streams. If released to air, a vapor pressure of 7.2X10-6 mm Hg at 25 °C indicates n-pentadecylbenzene will exist in both the vapor and particulate phases in the ambient atmosphere. Vapor-phase n-pentadecylbenzene will be degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals; the half-life for this reaction in air is estimated to be 16 hours. Particulate-phase n-pentadecylbenzene will be removed from the atmosphere by wet and dry deposition. If released to soil, n-pentadecylbenzene is expected to have no mobility based upon an estimated log Koc of 6.5. Volatilization from moist soil surfaces is expected to be an important fate process based upon an estimated Henry's Law constant of 0.79 atm-cu m/mole, but adsorption may severely attenuate this process. n-Pentadecylbenzene is not expected to volatilize from dry soil surfaces based on its vapor pressure. If released into water, n-pentadecylbenzene is expected to adsorb to suspended solids and sediment in the water column based upon the estimated log Koc. River die-away tests have shown that alkylbenzenes are readily biodegradable, with half-lives of 1.7 to 11.4 days for C-10 to C-13 isomers in river water. Volatilization from water surfaces is expected to be an important fate process based upon this compound's estimated Henry's Law constant, but adsorption may severely attenuate this process. Estimated volatilization half-lives for a model river and model lake are 5 hours and 7 days, respectively if adsorption is neglected. The estimated volatilization half-life from a model pond is 70 years if adsorption is considered. A BCF of 35 for dodecylbenzene measured in fish suggests that bioconcentration of n-pentadecylbenzene in aquatic organisms is moderate. Occupational exposure to n-pentadecylbenzene may occur through inhalation and dermal contact with this compound at workplaces where n-pentadecylbenzene is produced or used. The general population may be exposed to n-pentadecylbenzene via dermal contact with this compound and consumer products containing n-pentadecylbenzene. (SRC)