alpha-Methylstyrene dimer

TERRESTRIAL FATE: Based on a classification scheme(1), an estimated Koc value of 160,000(SRC), determined from a structure estimation method(2), indicates that alpha-methylstyrene dimer is expected to be immobile in soil(SRC). Volatilization of alpha-methylstyrene dimer from moist soil surfaces is expected to be an important fate process(SRC) given an estimated Henry's Law constant of 9.2X10-4 atm-cu m/mole(SRC), using a fragment constant estimation method(3). alpha-Methylstyrene dimer is not expected to volatilize from dry soil surfaces(SRC) based upon an estimated vapor pressure of 2.3X10-4 mm Hg(SRC), determined from a fragment constant method(4).

AQUATIC FATE: Based on a classification scheme(1), an estimated Koc value of 160,000(SRC), determined from a structure estimation method(2), indicates that alpha-methylstyrene dimer is expected to adsorb to suspended solids and sediment(SRC). Volatilization from water surfaces is expected(3) based upon an estimated Henry's Law constant of 9.2X10-4 atm-cu m/mole(SRC), developed using a fragment constant estimation method(4). Using this Henry's Law constant and an estimation method(3), volatilization half-lives for a model river and model lake are 3 hrs and 7 days, respectively(SRC). According to a classification scheme(5), an estimated BCF of 21,000(SRC), from an estimated log Kow of 6.5 and a regression-derived equation(6), suggests the potential for bioconcentration in aquatic organisms is very high(SRC).

ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), alpha-methylstyrene dimer, which has an estimated vapor pressure of 2.3X10-4 mm Hg at 25 °C(SRC), determined from a fragment constant method(2), is expected to exist solely as a vapor in the ambient atmosphere. Vapor-phase alpha-methylstyrene dimer is degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals and ozone(SRC); the half-lives for these reactions in air are estimated to be 7 and 2 hrs, respectively(SRC), calculated from its rate constants of 5.9X10-11 cu cm/molecule-sec and 1.4X10-16 cu cm/molecule-sec at 25 °C, respectively(SRC), derived using a structure estimation method(4).

Using a structure estimation method based on molecular connectivity indices(1), the Koc for alpha-methylstyrene dimer can be estimated to be 160,000(SRC). According to a classification scheme(2), this estimated Koc value suggests that alpha-methylstyrene dimer is expected to be immobile in soil(SRC).

alpha-Methylstyrene dimer's production and use as a chain transfer agent(1) may result in its release to the environment through various waste streams(SRC). alpha-Methylstyrene dimer is also a by-product of alpha-methylstyrene polymerization(1). Hence alpha-methylstyrene dimer may be released to the environment via effluents from alpha-methylstyrene polymerization(SRC).

An estimated BCF of 21,000 was calculated for alpha-methylstyrene dimer(SRC), using an estimated log Kow of 6.5 and a regression-derived equation(1). According to a classification scheme(2), this BCF suggests the potential for bioconcentration in aquatic organisms is very high(SRC).

The Henry's Law constant for alpha-methylstyrene dimer is estimated as 9.2X10-4 atm-cu m/mole(SRC) using a fragment constant estimation method(1). This Henry's Law constant indicates that alpha-methylstyrene dimer 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 3 hrs(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 6 days(SRC). alpha-Methylstyrene dimer's Henry's Law constant indicates that volatilization from moist soil surfaces may occur(SRC). alpha-Methylstyrene dimer is not expected to volatilize from dry soil surfaces(SRC) based upon an estimated vapor pressure of 2.3X10-4 mm Hg(SRC), determined from a fragment constant method(3).

The rate constant for the vapor-phase reaction of alpha- methylstyrene dimer with photochemically-produced hydroxyl radicals has been estimated as 5.9X10-11 cu cm/molecule-sec at 25 °C(SRC) using a structure estimation method(1). This corresponds to an atmospheric half-life of about 6 hours at an atmospheric concentration of 5X10+5 hydroxyl radicals per cu cm(1). The rate constant for the vapor-phase reaction of alpha-methylstyrene dimer with ozone has been estimated as 1.4X10-16 cu cm/molecule-sec at 25 °C(SRC) derived using a structure estimation method(1). This corresponds to an atmospheric half-life of about 2 hrs at an atmospheric concentration of 7X10+11 ozone molecules per cu cm(2). alpha-Methylstyrene dimer is not expected to undergo hydrolysis in the environment due to the lack of hydrolyzable functional groups(3).

alpha-Methylstyrene dimer's production and use as a chain transfer agent may result in its release to the environment through various waste streams. If released to air, an estimated vapor pressure of 2.3X10-4 mm Hg at 25 °C indicates alpha-methylstyrene dimer will exist solely as a vapor in the ambient atmosphere. Vapor-phase alpha-methylstyrene dimer will be degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals and ozone; the half-lives for these reactions in air are estimated to be 7 and 2 hrs, respectively. If released to soil, alpha-methylstyrene dimer is expected to have no mobility based upon an estimated Koc of 160,000. Volatilization from moist soil surfaces is expected to be an important fate process based upon an estimated Henry's Law constant of 9.2X10-4 atm-cu m/mole. If released into water, alpha-methylstyrene dimer is expected to adsorb to suspended solids and sediment based upon the estimated Koc. Volatilization from water surfaces is expected to be an important fate process based upon this compound's estimated Henry's Law constant. Estimated volatilization half-lives for a model river and model lake are 3 hrs and 7 days, respectively. An estimated BCF of 21,000 suggests the potential for bioconcentration in aquatic organisms is very high. Hydrolysis is not expected to occur due to the lack of hydrolyzable functional groups. Occupational exposure to alpha-methylstyrene dimer may occur through dermal contact with this compound at workplaces where alpha-methylstyrene dimer is produced or used. (SRC)

Basic treatment: Establish a patent airway. Suction if necessary. Watch for signs of respiratory insufficiency and assist ventilations if needed. Administer oxygen by nonrebreather mask at 10 to 15 L/min. Monitor for pulmonary edema and treat if necessary ... . Monitor for shock and treat if necessary ... . Anticipate seizures and treat if necessary ... . For eye contamination, flush eyes immediately with water. Irrigate each eye continuously with normal saline during transport ... . Do not use emetics. For ingestion, rinse mouth and administer 5 ml/kg up to 200 ml of water for dilution if the patient can swallow, has a strong gag reflex, and does not drool ... . Cover skin burns with dry sterile dressings after decontamination ... . /Poison A and B/

Advanced treatment: Consider orotracheal or nasotracheal intubation for airway control in the patient who is unconscious, has severe pulmonary edema, or is in respiratory arrest. Positive pressure ventilation techniques with a bag valve mask device may be beneficial. Monitor cardiac rhythm and treat arrhythmias as necessary ... . Start an IV with D5W /SRP: "To keep open", minimal flow rate/. Use lactated Ringer's if signs of hypovolemia are present. Watch for signs of fluid overload. Consider drug therapy for pulmonary edema ... . For hypotension with signs of hypovolemia, administer fluid cautiously. Watch for signs of fluid overload ... . Treat seizures with diazepam (Valium) ... . Use proparacaine hydrochloride to assist eye irrigation ... . /Poison A and B/