Abstract
The equilibrium distribution of platinum (IV) between hydrochloric acid and the neutral phosphine oxide extractants Cyanex 921 as well as Cyanex 925 in toluene are examined. From the concentration dependencies of the distribution ratio, it was determined that Pt(IV) is extracted as (H+·2R)2PtCl62- via ion-pair mechanism with both the extractants. The temperature dependence of the extraction equilibriums are examined by temperature variation method to estimate apparent thermodynamic function ΔH.
