Extraction of Gallium(III) from Hydrochloric Acid Solutions by Bis(dioctylphosphinyl)alkanes

Abstract

A series of bis(dioctylphosphinyl)alkanes (DOPO)₂R, where R can bep-xylydyl and (CH₂)_n(n=2, 3, 4, 5, 8 and 10), has been applied as extractants for gallium(III) ions from aqueous solutions of hydrochloric acid. These bis-type ligands have been found to be superior to the monodentate ligands such as trioctylphosphine oxide (TOPO) and benzyl dioctylphosphine oxide (Bz)DOPO. The extractability of the bis-type ligands, (DOPO)₂(CH₂)_n, depends on the methylene length (n) and decreases in the order of 5_??_10>3_??_4_??_8>2. The complexation of the gallium(III) ion with phosphoryl groups of the ligand has been confirmed by UV, IR and NMR spectroscopy.