SYNERGISTIC SOLVENT-EXTRACTION OF CERIUM(III) WITH MIXTURES OF THENOYLTRIFLUOROACETONE AND DIALKYL SULFOXIDES

Synergism in the extraction of Ce(III) from thiocyanate solutions has been investigated using mixtures of 2-thenoyltrifluoroacetone (HTTA) a nd bis-2-ethylhexyl sulfoxide (B2EHSO) or di-n-octyl sulfoxide (DOSO) in benzene. A very high synergistic enhancement of the order of 10(5) has been observed. If a mixture of both dialkyl sulfoxides (B2EHSO + D OSO) is used, an additional synergistic effect is found due to the for mation of a mixed, solvated complex when both reagents are added to th e metal chelate. These extraction data have been analyzed theoreticall y with the aid of a computer by taking into account complexation of th e metal in the aqueous phase by inorganic ligands and plausible comple xation in the organic phase. The equilibrium constants of the various product species have been deduced by non-linear regression analysis.