A study of interactions in mixtures of sodium dodecylsulphate and tris(1,10-phenanthroline) iron(II)

Abstract

The nature of the species and phases formed by interaction of tris(1,10-phenanthroline) iron(II) cation (Fe(ph)3,++) with dodecylsulfate anion (DS-) in aqueous media (Na2S04 = 0.05 mol. 1-1, pH=3) have been elucidated by means of microscopic observation and spectrophotometric measurements. For (ph)3,++ is shown to form a neutral ion pair with DS- in dilute solutions, and a 1:2 water-insoluble salt at higher concentrations of the two ions. This salt is solubilized by sodium dodecylsulphate micelles when surfactant is added in excess. Conditions leading to liquid-liquid phase separation and micellar solubilization are reported in a phase diagram.