FTIR spectroscopic investigations on the aggregation behaviour of N,N,N′,N′-tetraoctyldiglycolamide and N,N-dioctylhydroxyacetamide in n-dodecane during the extraction of Nd(III) from nitric acid medium

Abstract

Fourier Transform Infra Red (FTIR) spectroscopy is an excellent tool for probing the co-ordination chemistry of the solvent extracted metal complexes in organic phase. The organic phase containing tetraoctyldiglycolamide (TODGA) and N,N-dioctylhydroxyacetamide (DOHyA) ligands dissolved n-dodecane was employed for the extraction of Nd(III) from nitric acid medium. The extracted organic phase was probed by FTIR spectroscopy to understand the coordination chemistry and aggregation behaviour of Nd(III)-ligand complex in the binary solution. The results were compared with those obtained in the individual solvent system. The extraction of Nd(III) and nitric acid in organic phase was accompanied by shifting and broadening of amidic carbonyl stretching bands of TODGA and DOHyA, and the degree of shift or broadening was dependent on the amount of Nd(III) or nitric acid loaded in organic phase. Near complete shift of amidic carbonyl transmittance bands from 1660 cm−1 to 1610 cm−1 was observed prior to the undesirable event known as organic phase splitting. The results showed the possibility of employing the FTIR spectroscopic technique for understanding the extraction and for the prevention of organic phase splitting during the course of solvent extraction.