Abstract: The complex system of six kinds of different structure of alkyl aryl sulfonates(synthesized in the laboratory)/different alchol/n-decane/NaCl water microemulsions were investigated by Winsor phase diagram. The effects of molecular structure, temperature and alcohol were invetigated. The results showed that as the number of long alkyl carbon atoms in alkyl aryl sulfonate molecule increase, the values of S1, S2(the salt concentrations of middle-phase microemulsion appears or disappears), ΔS(salt concentration width) and S*(optimal concentration of salt) decrease, while the values of V*M(optimal volume of middle-phase microemulsion) and σ*(σ* means optimal solubilization) increase. Similar trends were also observed with the increase of temperature and carbon atom numbers of the alcohols and no middle phase microemulsion could be formed at 25 ℃. However, as the aromatic rings shift from the edge to the middle of the long carbonic chains, the values of S1, S2 and ΔS, S* decrease and those of V*M and σ* increase.

Key words: Alkyl Aryl Sulfonate, Microemulsion, Phase behavior, Winsor phase diagram