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The extraction of americium and lanthanides by diamides of 2,2′-dipyridyl-6,6′-dicarboxilic acid solutions in polar diluents was investigated. The dependence of extraction properties of the diamides on their structure was studied and the distribution ratios of americium and lanthanides from nitric acid solutions were determined. The highest extraction was found for the compounds with the ethyl-group and the alkyl-substituted aryl-group on the amidic nitrogen. The Am/Ln separation factors higher than 10 were achieved for extraction from high acidity media. [ABSTRACT FROM AUTHOR]

New ethyltolyl-substituted derivatives of dipicolinic acid,N,N-diethyl-N',N'-ditolyl diamides (DPA) have been synthesized and evaluated for their extraction capability toward americium and lanthanides. These diamides were studied as a stand-alone extractant in conjunction with a polar solvent FS-13 (trifluoromethylphenyl sulfone) as well as in an extraction mixture in conjunction with the synergistic extractant chlorinated cobalt dicarbollide and FS-13. The effect of the ortho-, meta-, and para position of the methyl group on the tolyl ring of theN,N'-diethyl-N,N'-ditolyl-diamide (EtTDPA) was investigated. Data on the extraction ability of different diamides of dipicolinic acid show that the Et(o)TDPA has the most promising properties because it has the best balanced selectivity between the heavy and light lanthanoids. [ABSTRACT FROM AUTHOR]

Abstract: New ligands for complexing of the post-transition metals – diamides of 2,2′-bipyridyl-6,6′-dicarboxylic acid were developed, synthesised and characterised. They were proposed to be effective extractants towards americium. The structures of the amides were studied in solid as well as in solution. Theextraction of Am and lanthanides depending on diamide structure, chlorinated cobalt dicarbollide (CCD) – diamide ratio, type of diluent was studied. The optimal conditions for Am/REE separation were determined. The properties of new potentiometric sensors on the base of 2,2′-dipyridyl-6,6′-dicarboxylic acid diamides were studied. The correlation structure vs. properties of ionophores (i.e. extractants), their sensitivity and selectivity in sensor analysis and extraction are discussed. [Copyright &y& Elsevier]

Extraction of microamounts of europium and americium by a phenyltrifluoromethyl sulfone (FS 13) solution of hydrogen dicarbollylcobaltate (H+B−) in the presence of N, N′-diethyl- N, N′-diphenyl-2,6-dipicolinamide (EtPhDPA, L) has been investigated. The equilibrium data have been explained assuming that the species HL+, HL2 +, ML2 3+, ML3 3+ and ML4 3+ (M3+ = Eu3+, Am3+) are extracted into the organic phase. The values of extraction and stability constants of the cationic complexes in FS 13 saturated with water have been determined. It was found that the stability constants of the corresponding complexes EuL and AmL, where n = 2, 3, 4 and L is EtPhDPA, in water-saturated FS 13 are comparable. [ABSTRACT FROM AUTHOR]

Extraction of microamounts of europium and americium by a nitrobenzene solution of hydrogen dicarbollylcobaltate (H+B−) in the presence of N,N,N′,N′-tetraethyl-2,6-dipicolinamide (TEtDPA, L) has been investigated. The equilibrium data have been explained assuming that the cations HL+, HL, ML and ML (M3+ = Eu3+, Am3+) are extracted into the organic phase. The values of extraction and stability constants of the species in nitrobenzene saturated with water have been determined. It has been found that the stability constants of the corresponding complexes EuL and AmL, where n = 2, 3 and L is TEtDPA, in the mentioned medium are comparable. [ABSTRACT FROM AUTHOR]

Three ortho-, meta-, and para-derivates of ethyl(tolyl)diamides of dipicolinic acid were synthesized and tested on their extraction performance from nitric acids solutions. Extraction of americium and lanthanides (Ln) by these compounds as a function of nitric acid concentration was studied. Distribution ratios of studied metals were determined using ICP-OES method and radiotracer 241Am. Am/Ln separation differs among studied diamides, and the best separation was found for N,N'-diethyl-N,N'-di(ortho)tolyl-diamide. [ABSTRACT FROM AUTHOR]

Extraction of Am and Eu with N,N′-substituted pyridine-2,6-dicarboxamides in fluorinated diluents was studied. N,N′-Diethyl- N,N′-di( p-tolyl)pyridine-2,6-dicarboxamide (EtTPDA) is readily soluble in fluorinated diluents, and its solutions allow the extraction of TPE and REE from nitric acid solutions. The extraction ability of EtTPDA in fluorinated polar diluents is higher than in CHCl3. In the extraction with EtTPDA, the Am/Eu selectivity is independent of the extractant concentration and decreases with an increase in the acidity of the medium. Americium is extracted with EtTPDA better than Eu, which allows selective recovery of Am at moderate HNO3 concentrations. [ABSTRACT FROM AUTHOR]

Extraction of Am and Eu using mixtures of diphosphinc dioxides (DPDO, e.g., (R1)2P(O)(CH2)nP(O)(R2)2 where R1, R2 = Ph, Bu; n = 1,2), with and without chlorinated cobalt dicarbollide (CCD) in the polar diluents 1,2-dichloroethane (DCE)+ meta-nitrobenzotrifluoride (F-3), bis-tetrafluoropropyl ether of diethylene glycol (F-8) and phenyltrifluoromethyl sulfone (FS-13) from HNO3, HClO4, LiNO3 and LiClO4 solutions has been investigated. The anomalous aryl strengthening (AAS) effect, i.e. the anomalous increase of extraction ability of methylene bridged diphosphine dioxides due to substitution of aromatic (i.e., phenyl) for alkyl (e.g., butyl or octyl) moieties (DAm increases by three to lour orders of magnitude), is only observed during the extraction of Am and Eu from acidic media. In salt media the AAS effect is weakly observed, and is practically absent in such diluents as F-3 and FS-13. The extraction isotherm in the case of DPDO with an observed AAS effect indicates the distribution coefficients of Eu decrease by a factor of two to three, even at the concentration ratio of DPDO:Eu = 50:1; however, these values decrease only by L0% for the DPDO that do not indicate an observed AAS effect. It is proposed that the presence of water in the diluent is necessary for manifestation of the AAS effect. The synergistic effects of adding chlorinated cobalt dicarbollide (CCD) with the DPDO that has been reported for other systems was also found to prevail in several of the systems investigated in this study. On addition of CCD with the DPDO, a considerable synergistic effect is observed (DAm increases by three to four orders of magnitude) during Am and Eu extraction from nitrate media, in perchlorate media the synergistic effect is absent. The most probable reason for synergism in the presence of CCD is the higher... [ABSTRACT FROM AUTHOR]

Extraction of Cs, Sr, Eu, U, Np, and Am with mixtures of dipicolinic acid diamides with chlorinated cobalt dicarbollide was studied. A synergistic effect was revealed. [ABSTRACT FROM AUTHOR]