PHASE-EQUILIBRIA IN THE SYSTEMS OF ACETIC AND GLYCOLIC ACID WITH WATER AND LAURETH-4

The effect of alpha-hydroxy group on the phase behavior in a skin loti on model system was studied by determining the phase diagrams for the two systems acetic acid/Laureth 4/white oil/water and glycolic acid/La ureth 4/white oil/water using visual observation by optical microscopy . The two acids when combined with surfactant and water gave an isotro pic liquid solution, and a lamellar liquid crystal with different amou nts of solubilization showing both acids to act as hydrotropes. The re sult provided essential information about the differences in the phase behavior which can attribute to the presence of alpha-hydroxy group i n the glycolic acid. Small angle x-ray diffraction was used to determi ne the boundaries of the lamellar liquid crystal phases in the two sys tems, both acids were found to be located in the water region in the l iquid crystal.