Effect of structure on extraction behavior of praseodymium with a series of unsymmetrical diglycolamides from hydrochloric acid

The extraction behavior of Pr(III) has been investigated using four kinds of unsymmetrical diglycolamide (DGA) extractants having different alkyl chain lengths, namely N,N'-dimethyl-N,N'-didodecyldiglycolamide (DMDDdDGA), N,N'-diethyl-N,N'-didodecyldiglycolamide (DEDDdDGA), N,N'-dipropyl-N,N'-didodecyldiglycolamide (DPDDdDGA) and N,N'-dibutyl-N,N'-didodecyldiglycolamide (DBDDdDGA). The effect of the alkyl chain of amidic N atoms in DGAs on the extraction ability of Pr(III) is discussed. The extraction of hydrochloric acid and Pr(III) from hydrochloric acid medium by DGAs in sulfonated kerosene, toluene and octanol was studied. The effect of extractant concentration and diluents on the distribution ratio (D) of Pr(III) was investigated to understand the extraction mechanism. Pr(III) and Fe(III) can be separated very well by DMDDdDGA and DBDDdDGA diluted by toluene in hydrochloric acid solution. IR spectra of extracted species of DGA-HCl and DGA-Pr(III) were recorded to study the structure of the extracted species.