Role of surfactants on the mutual solubility of phenol-water system

The effect of addition of surfartants, namely sodium dodecyl sulfate (anion ic), cetylpyridinium chloride (cationic) and Triton X-100 (nonionic) on the critical solution temperature (CST) of phenol-water system has been studie d. The CST of the system which increases initially, decreases with further addition of ionic surfactants, whereas the nonionic surfactant continuously increases the CST. The composition of phenol at CST increases with the inc rease in concentration of ionic surfactant.;in attempt has been made to exp lain the decrease/increase in CST in terms of micellar interaction.