Comprehensive extraction study using N,N-dioctylthiodiglycolamic acid: effect of S donor on metal extraction.

Extraction ability of N,N-dioctylthiodiglycolamic acid (T-DODGAA), a soft-base sulfur donor ligand with an amide group and a carboxylic acid connected by a thioether chain, for 56 metal ions have been comprehensively investigated and compared with that of N,N-dioctyldiglycolamic acid (DODGAA) with an etheric oxygen atom, a hard-base donor. The acid dissociation constant (pK) of the thiodiglycolamic acid framework was determined to be 3.71 ± 0.

Lanthanide extraction using a thiodiglycolamic acid extractant: effect of S-donor on lanthanide separation.

Liquid-liquid extraction of lanthanide (Ln) ions was investigated using N,N-dioctylthiodiglycolamic acid (DOTDGAA), which is a sulfur donor ligand with an amide group and a carboxyl group connected by a thioether chain. The extraction performance and selectivity of DOTDGAA for Ln ions were compared with those of N,N-dioctyldiglycolamic acid (DODGAA), which is also an oxygen donor ligand with a similar chemical structure, to assess the effect of the soft/hard donor atom on Ln separation. DOTDGAA quantitatively extracted all Ln ions while being selective toward the light and middle Ln ions, in contrast to the selectivity of DODGAA for heavier Ln ions.