Synergic Extraction of Rare Earths(III) with 4,4,4-Trifluoro-1-(2-thienyl)-1,3-butanedione and Nitrogen-Involving Polydentate Ligands as Diethylenetriamine and Triethylenetetramine

Abstract

Abstract The synergic extraction of rare earths(III), i.e. La, Sm, Tb, and Lu, using 4,4,4-trifluoro-1-(2-thienyl)-1,3-butanedione (Htta) and a nitrogen-involving neutral polydentate ligand, such as diethylenetriamine (dien) or triethylenetetramine (trien), was studied between benzene and aqueous phases. The synergic enhancement of this extraction system was attributed to the formation of an adduct, RE(tta)3dien or RE(tta)3trien. The adduct formation constants (βS,1) were determined. Although βS,1 decreases with the atomic number of RE(III), the detailed tendency of βS,1 depends on the number of nitrogen atoms of the polydentate ligands.