Toluene Solubility in Water and Organic Partitioning from Gasoline and Diesel Fuel into Water at Elevated Temperatures and Pressures

A simple and reliable system for determining the solubility and partitioning behavior of liquid fuel components in liquid water up to 250 °C has been developed. The system shows good agreement with literature values at ambient temperature for the solubility of toluene and for fuel/water partitioning coefficients (Kfw). Toluene solubility increased ∼23-fold by raising the temperature from ambient to 200 °C but was not affected at ambient temperature by changing the pressure from 1 to 50 bar. The increases in partitioning of benzene, toluene, ethylbenzene, xylenes, and naphthalene from gasoline into liquid water with increasing temperature ranged from 10-fold for benzene to 60-fold for naphthalene when the temperature was raised from ambient to 200 °C. Similarly, the increases in partitioning of polycyclic aromatic hydrocarbons from diesel fuel into liquid water ranged from ∼130-fold for naphthalene to 470-fold for methylnaphthalene when the temperature was raised from ambient to 250 °C. The effect of temperature on the partitioning of naphthalene into water from gasoline and from diesel fuel was similar, indicating that the fuel composition had little effect on the fuel/water partitioning behavior.