Collection of Czechoslovak Chemical Communications - digital archive 

Abstract

The extraction of hafnium(IV) with N-benzoyl-N-phenylhydroxylamine solutions in chloroform or toluene from strongly acid (HClO₄) solutions of dimethyl sulfoxide or hexamethylphosphor triamide has been studied. These substances were found to suppress the conversion of the extraction mechanism from ion exchange to solvation: while in solutions free of these substances this conversion takes place at HClO₄ concentrations of about 4 mol l^-1, in the mixed aqueous-organic (polar) phase the requisite acid concentrations are considerably higher. The possible causes of this effect are discussed.