Surface Activity, Adsorption, and Micellization Parameters of Ammonium Surfactants Containing a Hydroxyethyl and Hydroxyisopropyl Head Group

On the basis of measurements of conductivity and surface activity, adsorption and micellization parameters such as critical micellization concentration (CMC), adsorption efficiency, effectiveness of surface tension reduction, and a degree of counterion dissociation (α) for four new ammonium surfactants, octyl-N-(2-hydroxyethyl)-N-(2-hydroxypropyl) ammonium chloride, nonyl-N-(2-hydroxyethyl)-N-(2-hydroxypropyl) ammonium chloride, dodecyl-N-(2-hydroxyethyl)-N-(2-hydroxypropyl) ammonium chloride, and hexadecyl-N-(2-hydroxyethyl)-N-(2-hydroxypropyl) ammonium chloride in aqueous solutions have been determined. The values of CMC determined by two different methods are compared, and they show reasonable agreement. Using the results of electroconductometric and tensiometric measurements, enthalpy (ΔH), the Gibbs free energy (ΔG), and entropy (ΔS) for processes of adsorption and micellization have been computed. The influence of the length of the alkyl chain in the synthesized salts on surface activity and thermodynamic parameters has been clarified. The petrocollecting capacity of the obtained surfactants has been studied on the surface of waters having various mineralization degrees. It has been revealed that the surfactant containing C12 chain is the most effective petrocollecting reagent among the synthesized salts. © 2017 American Chemical Society.