Gas solubilities in a three-phase oil—water—surfactant system

Abstract

One-atmosphere solubilities of three gases, argon, methane, and ethane, have been measured at 25°C in the oil-rich (O), water-rich (W), and middle phases of a Winsor type III three phase system composed of n-octane, an aqueous solution of sodium bromide, and a surfactant/cosurfactant blend of cetyltrimethylammonium bromide (CTAB) and n-butanol. The solubilities measured in the (O) and (W) phases are substantially the same as those found for pure n-octane and dilute aqueous solutions of CTAB, while those determined for the middle phase are found to vary with n-octane content in a systematic manner. The middle-phase solubilities measured for these gases agree reasonably well with values calculated assuming that each of the liquid components present in the middle phase acts independently and contributes to the overall solubility as if it were present as a pure liquid.