Vinyl sulfoxide

Using a structure estimation method based on molecular connectivity indices(1), the Koc for vinyl sulfoxide can be estimated to be 16(SRC). According to a classification scheme(2), this estimated Koc value suggests that vinyl sulfoxide is expected to have very high mobility in soil.

The oxidation of mustard gas can result in the formation of mustard sulfoxide; the sulfoxide can further react forming vinyl sulfoxide(1). Therefore, vinyl sulfoxide may be formed during the chemical decontamination of mustard gas(1) and released during this process to the environment through various waste streams(SRC).

An estimated BCF of 3 was calculated for vinyl sulfoxide(SRC), using an estimated log Kow of -0.5(1) and a regression-derived equation(2). According to a classification scheme(3), this BCF suggests the potential for bioconcentration in aquatic organisms is low.

The Henry's Law constant for vinyl sulfoxide is estimated as 3.9X10-7 atm-cu m/mole(SRC) using a fragment constant estimation method(1). This Henry's Law constant indicates that vinyl sulfoxide is expected to be essentially nonvolatile from water surfaces(2). Vinyl sulfoxide's Henry's Law constant(1) indicates that volatilization from moist soil surfaces is not expected(SRC). The potential for volatilization of vinyl sulfoxide from dry soil surfaces may exist(SRC) based upon an estimated vapor pressure of 1.6 mm Hg(SRC), determined from a fragment constant method(3).

The rate constant for the vapor-phase reaction of vinyl sulfoxide with photochemically-produced hydroxyl radicals has been estimated as 1.1X10-10 cu cm/molecule-sec at 25 °C(SRC) using a structure estimation method(1). This corresponds to an atmospheric half-life of about 3 hours at an atmospheric concentration of 5X10+5 hydroxyl radicals per cu cm(1). Vinyl sulfoxide may also react with atmospheric ozone with an estimated rate constant for this reaction of 3.5X10-18 cu cm/molecule-sec at 25 °C(SRC) using a structure estimation method(1). This corresponds to an atmospheric half-life of about 3 days at an atmospheric concentration of 7X10+11 ozone molecules per cu cm(1). Vinyl sulfoxide is not expected to undergo hydrolysis in the environment due to the lack of hydrolyzable functional groups(2).

Vinyl sulfoxide may be formed during the chemical decontamination of mustard gas and released during this process to the environment through various waste streams. If released to air, an estimated vapor pressure of 1.6 mm Hg at 25 °C indicates vinyl sulfoxide will exist solely as a vapor in the ambient atmosphere. Vapor-phase vinyl sulfoxide will be degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals and ozone molecules; the half-lives for these reactions in air are estimated to be 3 hours and 3 days, respectively. If released to soil, vinyl sulfoxide is expected to have very high mobility based upon an estimated Koc of 16. Volatilization from moist soil surfaces is not expected to be an important fate process based upon an estimated Henry's Law constant of 3.9X10-7 atm-cu m/mole. Vinyl sulfoxide may volatilize from dry soil surfaces based upon its estimated vapor pressure. Under anaerobic conditions in soil or sediment, vinyl sulfoxide may be microbially reduced to the sulfide. If released into water, vinyl sulfoxide is not expected to adsorb to suspended solids and sediment based upon the estimated Koc. Volatilization from water surfaces is not expected to be an important fate process based upon this compound's estimated Henry's Law constant. An estimated BCF of 3 suggests the potential for bioconcentration in aquatic organisms is low. Occupational exposure to vinyl sulfoxide may occur through inhalation and dermal contact with this compound at locations where mustard gas is decontaminated. (SRC)