2-Nitropropane

2-Nitropropane's production and use as a solvent in inks, paints, adhesives, varnishes, and polymers, a solvent for vinyl and epoxy coatings, an ingredient in rocket propellent, and a gasoline additive may result in its release to the environment through various waste streams. If released to air, an estimated vapor pressure of 17.2 mm Hg at 25 deg C indicates 2-nitropropane will exist solely as a vapor in the atmosphere. Vapor-phase 2-nitropropane 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 95 days. 2-Nitropropane is expected to undergo direct photolysis in the atmosphere based on 95% degradation after 24 hours and a half-life of 9.8 days measured during tests for photodegradation. If released to soil, 2-nitropropane is expected to have very high mobility based upon Koc values of 0.11 and 3.8. Volatilization from moist soil surfaces is expected to be an important fate process based upon an estimated Henry's Law constant of 1.19X10-4 atm-cu m/mole. The pKa of 2-nitropropane is 7.68, indicating that this compound will partially exist in anion form in the environment and anions generally do not adsorb more strongly to organic carbon and clay than their neutral counterparts. 2-Nitropropane may volatilize from dry soil surfaces based upon its vapor pressure. Biodegradation in soil is expected to be slow based on 3.0 and 1.2% conversion to CO2 in aerobic and anaerobic soil, respectively after 35 days. If released into water, 2-nitropropane is not expected to adsorb to suspended solids and sediment based upon the Koc values. Biodegradation in water is expected to be slow based on 0.8% mineralization after 5 days using activated sludge and 0.1-14% degradation in 28 day closed bottle tests. Volatilization from water surfaces is expected to be an important fate process based upon this compound's estimated Henry's Law constant. A pKa of 7.68 indicates 2-nitropropane will exist partially in the anion form at neutral and basic pH and therefore volatilization from water surfaces may be hindered under these conditions. Estimated volatilization half-lives for a model river and model lake are 6 hours and 6 days, respectively. Hydrolysis is not expected to be an important environmental fate process since this compound lacks functional groups that hydrolyze under environmental conditions. Occupational exposure to 2-nitropropane may occur through inhalation and dermal contact with this compound at workplaces where 2-nitropropane is produced or used. The general population may be exposed to 2-nitropropane via inhalation of ambient air and dermal contact with this compound and other products containing 2-nitropropane. (SRC)