Ion-exchange extraction of proline with liquid sulfo cation exchanger

The extraction of proline with a solution of dinonylnaphthalenesulfonic aci d in octane, a liquid cation exchanger, from aqueous and aqueous salt-conta ining solutions was investigated. It was shown that the dependence of the s electivity coefficient on the equivalent fraction of proline in the liquid cation exchanger phase is adequately described by a mathematical model prop osed previously under the assumption that at least four nearest neighboring ions affect the interaction energy of the cation and the anion of proline on a given exchange site.