Abstract: Extraction of HPdCl₄^- and PtCl₆^2- with trialkyl benzyl ammonium chloride(7407)from hydrochloric acid medium has been studied. On the basis of the influences of tempera-ture and concentration of 7407 upon the distribution ratio D_pd and D_pt, the extraction equi-librium constants and some thermodynamic functions at 30℃ were obtained:K_pd=2.92×10⁴, K_pt=1.44×10⁶;△H_pd=-8.37kJ/mol, △H_pt=-24.5kJ/mol;△G_pd=-25.9kJ/mol, AG_pt=-35.7kJ/mol;△S_pd=57.8J/mol.K, △S_pt=37.0J/mol.K.

Key words: extraction, palladium, platinum, trialkyl benzyl ammonium chloride, thermodynamics