Synergic extraction of rare earths with 2-thenoyltrifluoroacetone and phophoryl-type bidentate ligands such as tetraphenyldiphosphine dioxide or bis(diphenylphosphinyl) methane

Abstract

The synergic extraction of rare earth(III) ions (RE; La, Sm, Tb and Lu) using 2-thenoyltrifluoroacetone (Htta) and phosphoryl-type uncharged bidentate ligands, such as tetraphenyldiphosphine dioxide (tpdpo) or bis(diphenyl-phosphinyl)methane (bdppm), was investigated in benzene. The synergic enhancement was attributed to the formation of the adduct RE(tta) 3S n ( n=1 or 2 for tpdpo and n=1 for bdppm) in benzene, where S denotes the uncharged ligand. The adduct formation constants (β S) and the synergic extraction constants were determined. For each RE(III), the β S,1 value for bdppm is larger than the β S,1 and β S,2 values for tpdpo and the β S values for both ligands decrease with increasing atomic number of RE(III).