Stereochemically enriched extractants for the extraction of actinides

Abstract

Numerous studies on the understanding of extraction mechanisms and complex structures have been done for hydrometallurgical processes. However, investigations on the influence of extractants stereochemistry on extraction performances has not...

Synthesis and evaluation of new modified diglycolamides with different stereochemistry for extraction of tri- and tetravalent metal ions

“…Even higher distribution ratios are expected for the syn-Et-Me-TODGA 4A diastereomer as the syn-diastereomers of these diglycolamide extractants usually give higher distribution ratios than the antidiastereomer. 23,30 However, the syn-Et-Me-TODGA 4A diastereomer was synthetically unavailable and could not be tested in the current study. The differences in extraction by the different diastereomers was explained by the steric hindrance and orientation created by the alkyl groups of the ligand backbone hindering the nitrate ion complexation in the outer sphere of the complexes influencing their selectivity for Am(III) over Cm(III).…”

“…The differences in extraction by the different diastereomers was explained by the steric hindrance and orientation created by the alkyl groups of the ligand backbone hindering the nitrate ion complexation in the outer sphere of the complexes influencing their selectivity for Am(III) over Cm(III). 23,[28][29][30] The dipropyl substituted DGAs with the same orientation in both analogues showed similar behaviour. Anti-Orientation gave very low D values in a close range (0.005-0.009) slightly above the lower detection limit, without major differences among the HNO 3 concentration.…”

“…The differences in extraction by the different diastereomers was explained by the steric hindrance and orientation created by the alkyl groups of the ligand backbone hindering the nitrate ion complexation in the outer sphere of the complexes influencing their selectivity for Am( iii ) over Cm( iii ). 23,28–30…”

“…23 Generally, the influence of the stereochemistry of extractants has yet only received little attention in the field of spent nuclear fuel treatment, despite the evidence on extraction differences caused by the orientation in ligands. 23,[26][27][28][29][30][31] Based on these results, n-octyl and n-decyl DGAs were synthesised with dipropyl and ethyl-methyl substituents in the backbone of the molecules and their respective syn-and anti-isomers were isolated (Fig. 1), and their extraction behaviour and selectivity for An(III) and Ln(III), and specifically for Am(III) and Cm(III) was studied.…”

Stereo‐ and Regiochemical Effect of N,N‐Dialkylamide Extractants on the Speciation of Pu Complexes

“…In a previous work, we studied the effect of stereochemistry of some monoamide ligands on the complexation of plutonium in extraction conditions (see Felines et al [33] ). Optically pure diastereoisomers of the N,N-di(2-ethylhexyl)butyramide (DEHBA) extractant were synthesized and the effect of their stereoisomerism on uranium and plutonium coextraction were investigated at two different acidities.…”