3-PHASE BEHAVIOR IN A MIXED SUCROSE ALKANOATE AND POLYETHYLENEGLYCOL ALKYL ETHER SYSTEM

Interesting three-phase behavior was investigated in water/sucrose monolaurate/tetraethyleneglycol dodecyl ether/heptane and water/sucrose dilaurate/octaethyleneglycol dodecyl ether/heptane systems. The three-phase region is largely skewed to a higher temperature in a dilute region, and phase inversion in emulsion type is observed twice at a fixed composition in the former system. In contrast, the three-phase body is shifted toward lower temperatures with decreasing surfactant concentration in the latter system. Although a sucrose ester is a mixture of isomers, it can be treated as a pseudo-single component because its monodisperse solubilities in water and oil are very small. These phenomena were analyzed by an equation that describes a particular three-phase triangle in a space of compositions. The difference in monodisperse solubilities of each surfactant in oil causes the interesting three-phase behavior in the mixed surfactant system. The Hydrophile-Lipophile Balances (HLBs) of sucrose alkanoates were also evaluated from the three-phase behavior using the same equation. © 1993 Academic Press, Inc.