Abstract: The properties of microemulsion formed by three alkyl aryl sulfonates(synthesized in the laboratory) in the multi-component systems were investigated by Winsor phase diagram and pseudo-ternary phase diagram methods. The influences of molecular structure, inorganic salt and short chain alcohol on these microemulsion properties were discussed, respectively. The results show that as the concentration of inorganic salt increases, the surfactants/n-butanol/n-octane/NaCl/water microemulsion systems transform from WinsorⅠ to Winsor Ⅲ and then to WinsorⅡ at certain temperature. With the increase of the number of long alkyl carbon atoms in alkyl aryl sulfonate molecule, the salt-toleran ability decreases but the solubilization capacity increases. With the increase of carbon atom number of the alcohol, the area of microemulsion region increases first and then decreases. When molecular structure of alkyl aryl sulfonate is fixed, the choice of alcohol is based on Bansal theory for the biggest microemulsion region. When the chain length of alcohol is determined, with the increase of the number of long alkyl carbon atoms in alkyl aryl sulfonate molecule, the area of microemulsion region will decrease.

Key words: Alkyl aryl sulfonate, Microemulsion, Winsor phase diagram, Pseudo-ternary phase diagram