Experimental Investigations of Oxygenated Gasoline Dissolution

Oxygenated compounds such as ethanol and MTBE are added to gasoline in many countries to increase the octane rating and to reduce the carbon monoxide and ozone levels in the air. In Brazil, due to economic reasons, gasoline has had up to 26% ethanol added. The leakage or spillage of such gasolines, referred to as oxygenated gasolines, could induce a cosolvent flushing effect in the contaminated soil as a result of the high solubility of oxygenated compounds in water. This paper focuses on the experimental measurements of the enhanced concentration and the dissolution of 12 organic compounds with increasing percentages of ethanol in the gasoline phase. The validity of Raoult's law and the log-linear cosolvency model to estimate the aqueous concentration of the hydrocarbons from unamended and from oxygenated gasolines is verified. Column tests showed that ethanol is leached out of residual gasoline after a short time, leaving an ethanol-free residual phase.