Mesityl Oxide

CAS RN:141-79-7

Exposure Summary

Mesityl oxide's production and use in manufacturing methyl isobutyl ketone, and its use as an intermediate, solvent for nitrocellulose and vinyl chloride-vinyl acetate resins, additive, or mineral extractant may result in its release to the environment through various waste streams. Mesityl oxide's use as an insect repellent will result in its direct release to the environment. If released to air, a vapor pressure of 8.21 mm Hg at 25 deg C indicates mesityl oxide will exist solely as a vapor in the atmosphere. Vapor-phase mesityl oxide will be degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals and ozone; the half-life for these reactions in air are estimated to be 4.9 hours and 1.4 hours, respectively. Mesityl oxide will also react with atmospheric nitrate with a half-life of 3.9 hours. Vapor-phase mesityl oxide undergoes direct photolysis with an experimental half-life and rate constant of 76.8 hrs and 8.75X10-3/hr, respectively. If released to soil, mesityl oxide is expected to have very high mobility based upon an estimated Koc of 15. Volatilization from moist soil surfaces is expected to be an important fate process based upon an estimated Henry's Law constant of 3.67X10-5 atm-cu m/mole. Mesityl oxide may volatilize from dry soil surfaces based upon its vapor pressure. Theoretical %BOD values of 74 and 30 from studies done with sewage inoculum suggest that biodegradation may be an important environmental fate process. If released into water, mesityl oxide is not 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 17 hours and 11 days, respectively. An estimated BCF of 1.9 suggests the potential for bioconcentration in aquatic organisms is low. 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 mesityl oxide may occur through inhalation and dermal contact with this compound at workplaces where mesityl oxide is produced or used. Monitoring data indicate that the general population may be exposed to mesityl oxide via inhalation of ambient air, ingestion of food and drinking water, and dermal contact with insect repellents and other products containing mesityl oxide. (SRC)
Find more information on this substance at: Hazardous Substances Data Bank , TOXNET , PubMed