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- Author or Editor: Xu-Fang Tan x
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Abstract
N,N,N′,N′-tetrabutylmalonamide (TBMA) was used for extraction of uranyl(II) ion from nitric acid media into n-dodecane. The effects of nitric acid concentration, extractant concentration, temperature and back extraction on distribution coefficients of uranyl(II) ion have been studied. The extraction of nitric acid is also studied. The main adduct of TBMA and HNO3 is (TBMA)2·HNO3 in 1.0 mol/l nitric acid solution. The 1:2:2 complex of uranyl(II) ion, nitrate ion and TBMA as extracted species is further confirmed by IR spectra of the extraction of uranyl(II) ion with TBMA. The values of thermodynamic parameters have also been calculated.
Abstract
N,N,N′,N′-tetrahexylsuccinylamide (THSA) was used for the extraction of U(VI) and Th(IV) ions from nitric acid media into n-dodecane. Extraction distribution ratios of U(VI) and Th(IV) as a function of nitric acid concentration, extractant concentration and temperature have been studied. It was found that THSA as a new extractant is superior in some aspects to TBP for extraction of U(VI) and Th(IV). The extraction of nitric acid was also investigated. At low acidity, the main adduct of THSA and HNO3 is THSA·HNO3. THSA·(HNO3)2 and THSA·(HNO3)3 also formed at high acidity. The composition of the species, equilibrium constants and enthalpies of the extraction reactions have also been calculated. The suggested formation of the 1:2:1 ratio of uranyl(VI) ion and the 1:4:2 ratio of thorium(IV) ion, nitrate ion and THSA as the extracted species was further confirmed by the IR spectra of U(VI) and Th(IV) extracts.
Abstract
Five kinds of solid coordination complexes of uranium(VI) and thorium(IV) with the diamide (N,N,N
,N-tetrabutylmalon-amide (TBMA), N,N,N,N-tetrabutylsuccinylamide (TBSA), N,N,N,N-tetrabutylglutaramide (TBGA), N,N,N,N-tetrabutyl-adipicamide (TBAA)) were synthesized. All these complexes of UO2(NO3)2·TBMA, UO2(NO3)2· TBSA, [UO2(NO3)2·(TBGA1/2)2]
x
, UO2(NO3)2·TBAA and Th(NO3)4·2TBMA were characterized by elemental analysis, UV spectra, IR spectra and 13C NMR spectra. The coordination form and proposed structures of the complexes are also discussed.
