Determination of the partition constant of aniline between aqueous and micellar phases in solutions of sodium dodecylsulfate and dodecyltrimethylammonium bromide by a potentiometric method and by measurement of density

We have determined the partition constants of aniline between aqueous and micellar phases in solutions of sodium dodecylsulfate (NaDDS) and dodecyltrimethylammonium bromide (DDTABr). We used two different methods: the first determination was based on measurements of density of the solutions consisting of microadditions of the solute A (aniline) to several samples of water, surfactant and background electrolyte. The second was based on measurements of pH of buffer solutions made by mixing aniline, and anilinium cation in solutions of positive micelles. Using the pseudophase model, the results obtained are in good agreement for the different methods.