Dodecanesulfonates (isomer mixtures) have been synthesized by the process developed in our laboratory. First, pseudoternary phase diagrams of water or (brine) decane/dodecanesulfonates-butan-1-ol systems were drawn and compared with those of a commercial sample (Hostapur 60). In the presence of NaCl, a three-phase region (Winsor III) appears for the two systems, and is larger with the home-made surfactants. This region is interesting in enhanced oil recovery because it leads to very low interfacial tensions. Then, the behavior of the Winsor III region was investigated as a function of the alcohol/surfactant mass ratio (C/T). At a constant salinity (2.5 mass% NaCl) a value of 2 for C/T gives the best compromise for a larger WIII region with both systems. For this ratio, optimal salinity values of 1.55 and 1.65 mass% for our sample and Hostapur 60, were found, respectively.