Abstract
Phase behavior of three coexisting phases, i.e., surfactant, water and oil phases has been studied in pseudo four-component system of C8H17SO3Na/octanol/brine/2, 2, 4 trimethylpentane. Assuming that 1) most of surfactant is dissolved in a surfactant phase, 2) cosurfactant (octanol) is distributed among surfactant and oil phases, 3) brine is regarded as one component, a simple method to determine the plane of the three-phase triangle in a composition tetrahedron of the pseudo four-component system was obtained. By this method, it was found that the solubility of octanol in the surfactant phase is increased with increasing salinity, whereas that in the oil phase is decreased.
