The boundary of the two-phase liquid equilibrium area in an aqueous self-stratifying and protolytically interacting system based on alkyl benzene sulfonic acid (ABSA) and antipyrine (Ant) was determined by isothermal titration at 23±2°C. The potentiometric method was used to determine the dissociation constant of alkyl benzene sulfonic acid. The optimum concentration parameters of the extraction process in the system under investigation were determined. The aliquation stability and the phase volume ratio as dependent on inorganic acids (hydrochloric, sulfuric) and ammonium thiocyanate were studied. With addition of up to 2.5 mol/l of HCl, 2.0 mol/l of H₂SO₄ and 0.3 mol/l of NH₄SCN, the two-phase liquid equilibrium area is maintained. Interfacial distribution of Sc(III), La(III), Ga(III), Fe(III), Tl(III) and Cu(I) in the H₂O – Ant – ABSA system from hydrochloric solutions was studied. Conditions for quantitative extraction of iron, scandium and thallium are found. Exploration of extraction of Fe(III), Zn(II), Co(II), Cu(II) and Cd(II) from thiocyanate solutions enable ascertaining optimal conditions for quantitative extraction of zinc, copper and iron.