Synergism in the Extraction of Ru(III) by a Tri-n-Octylamine–Di-n-Hexylsulfide System

Abstract

We have found that a mixture of tri-n-octylamine (TOA) and di-n-hexylsulfide (DHS) in CHCl₃ displays synergistic extraction of Ru(III) from aqueous HCl. Approximately 55% of Ru(III) was extracted by a 0.25 M TOA–0.25 M DHS system, whereas a single extractant, 0.25 M TOA or 0.25 M DHS, achieves hardly any Ru(III) extraction. Job plots of the extraction of Ru(III) from 5 M HCl aqueous solution indicate formation of a complex with 1:2:1 Ru(III):TOA:DHS stoichiometry. UV-Vis absorption spectra of the extracted Ru(III) complexes suggest that a DHS molecule is bound to the Ru(III) ion in the inner coordination sphere.