INVESTIGATIONS ON THE SEPARATION OF PD(II)-PT(IV) PAIR BY EXTRACTION CHROMATOGRAPHY IN THE SYSTEM - LIQUID ANION EXCHANGER-ARSENAZO-III OR CHROMOTROP-2B

The possibility of separation of the pair Pd(II)-Pt(IV) in the form of their complexes Arsenazo III or Choromotrop 2B was investigated using chromatographic columns packed with silica gel impregnated with Aliquat 336. Arsenazo III forms complexes with both metals at room temperature; however their affinities to liquid anion exchanger are similar and the separation of both metals using perchloric acid solutions or mixtures of hydrochloric and nitric acid as eluents was found to be impossible. Chromotrop 2B, depending on the reaction conditions forms with palladium and platinum a few complexes. During 30 minutes heating of the solutions of H2PtCl6 with an excess of the chelating reagent (the concentration of Chromotrop 2B was 9-fold higher than the concentration of platinum) on the boiling water bath, 70% of platinum formed blue-green complex of the type PtL2. The relative affinities of palladium and platinum complexes to Aliquat 336 increase in the following order PtCl62- < < PdL(n)<PtL2 what makes possible the separation of both metals by column extraction chromatography.