Solvent extraction of palladium (II) and platinum (IV) from aqueous chloride media with N,N-dioctylglycine

Solvent extraction of palladium(II) and platinum(IV) from acidic aqueous chloride media with N,N-dioctylglycine in toulene was investigated. The experimental results of the distribution equilibria suggested that palladium(II) is extracted as a 1 : 2 metal : reagent chelate according to the reaction: PdCL24−+H2R2⇋PdR2+2H++4Cl− The data indicated that platinum(IV) was extracted as a 1 : 4 : 2 metal : chloride ion : reagent complex according to the solvating reaction: PtCL26−+H2R2⇋Pt·2HR·Cl4+2Cl− The equilibrium constants for these extraction reactions were evaluated as Ke = 2.2 × 102 (mol/dm3)5 for palladium(II) and Ke = 6.3 × 102 (mol/dm3). Infrared spectra of the free reagent and the glycino complexes of these metals were studied to obtain some information on the interaction between metal ions and the reagent molecules.