Abstract: The molecular dipole moment, as a very useful parameter for structural studies, has been applied to study the intermolecular interaction, such as association reaction, etc., between two extractants or extractant and extraction complex.The molar polarizabilities Pand dipole moments μ of some important extractants containing phosphorus TBP, TOPO, TBPO, P₂₀₄, DBP, HDiAP, DiAEPin benzene were determined by use of dielectric measurements. These results are summarized in Table 1.Molecular-interaction between acidic and neutral extractants containing phosphorus has been studied by the same method. These formation constants K_c, molar polarizabilities Pand dipole moments μ of complexes are shown in Table 2.Dielectric property of mixed solution can be applied to the study of synergistic extraction systems.

Key words: Extraction, Molar polarizability, Dipole mement, Synergistic extraction