An apparatus has been designed and constructed to measure liquid hydrocarbon solubility in water. On-line analysis coupled with gas chromatography has been applied to the determination of binary mixtures of water with benzene and cyclohexane for the temperature range (70 to 150) °C. Measurements obtained for benzene show good agreement with literature values and allow us to validate this new method. Increasing the temperature from 70 °C to 150 °C increases the mole fraction solubility of cyclohexane in water from (19.7 ± 0.02) × 10-6 to (131 ± 3) × 10-6.

A solid-phase extraction method has been developed for measuring low solubilities of hydrocarbon in water. The solubilities of hexane, heptane, and octane in water were determined at temperatures ranging from (30 to 180) °C. The solubilities of alkanes in water at 30 °C decrease with increasing carbon number. At 30 °C, the mole fraction solubility is (2.06 ± 0.01) × 10-6 for hexane and (0.120 ± 0.002) × 10-6 for octane. The temperature effect on solubility in water is much more important for octane than for hexane. Increasing the temperature from (30 to 180) °C increases the solubilities by a factor of 23 for hexane and 110 for octane.