Complex Formation and Liquid-Liquid Extraction in the Niobium(V) – 2,4-Dihydroxythiophenol– Hydrophobic Amines System

Abstract

The formation and solvent extraction of new ion-association comple- xes between anionic chelat of niobium(V) with 2,4-dihydroxythiophenol (DHTP) and hydrophobic amines (HAs). The HAs were aniline (An), N-methylaniline (MAn), N,N-dimethylaniline (DAn). The optimum conditions for the extraction of mixed ligand complexes (MLC) (organic solvent, extraction time, acidity of the aqueous phase, concentration of reagents), some key constants {association constant (β), extraction constant (Kex)} and analytical characteristics were determined. The molar absorptivities of MLC were calculated ε =(3.5-3.9) × 10⁴ L mol^–1 cm^–1 . The Beer’s law was applicable in the range of 2.2-100 μg/mL.