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The partition behaviors of some dyes, anthraquinones, and tanshiones in two kinds of aqueous two-phase systems (ATPSs) have been investigated. The partition constants (K) of ionic dyes and rhein in the first kind of ATPSs are dependent on hydrophobic and electrostatic interactions. A correlation forKas a function of the concentration ratio of total surfactant ions and surface net charge ratio of aggregates between the two coexisting phases has been proposed. Almost 100% of water-insoluble electroneutral extract accumulates in surfactant-rich phase of the first kind of ATPS due to hydrophobic interaction.Kof emodin in the second kind of ATPSs is correlated by the same model regardless of electrostatic interaction. [ABSTRACT FROM PUBLISHER]

Phase behavior of aqueous mixed surfactants, 1,3‐propanediyl bis(dodecyl dimethylammonium bromide) and sodium dodecyl sulfonate, has been studied at 318.15 K. The influence of added sodium halides (NaF, NaCl, and NaBr) has been investigated. For those systems studied, only one aqueous two‐phase region is formed in which cationic gemini surfactant is in excess. Different salt effects on the densities of the concentrated phases in aqueous two‐phase systems were observed for the three sodium halides. Density experiments indicate that contributions of various ions and water to the density of the solutions are near additive. Whether the concentrated phases in aqueous two‐phase systems are the bottom phases with higher densities or not are dependent on the different counterion binding ability and on the different contribution to the density of the three halides. [ABSTRACT FROM AUTHOR]