Interactions between large organic ions of opposite charge. I. Stoichiometry of the interactions of sodium dodecyl sulfate with benzyltriphenylphosphonium chloride

Abstract

The interaction between sodium dodecyl sulfate (SDDS) and benzyltriphenyl phosphonium chloride (BTPC) is characterized by three separate regions. Region I, where ion-pair association occurs and the species (BTP+DDS−) exists in equilibrium with the homogeneous solution of the ions. Region II, where complexation occurs as governed by the 1:1 solubility product, produces a heterogeneous phase separation and equilibrium solution that contains the free ions and the ion-pair (BTP+DDS−). Region III, where micelle formation by excess DDS− in the presence of BTP+, ion pairs, separated complex and inorganic counter ions, results in the solubilization of the complex and brings about a homogeneous clear solution.