Extraction and separation of Am(III) and Sr(II) by N,N,N´,N´-tetraoctyl-3-oxapentanediamide (TODGA)

Suzuki, H.; Sasaki, Yoshiyuki; Sugo, Yumi; Apichaibukol, A.; Kimura, Takaumi

doi:10.1524/ract.92.8.463.39276

Cited by 92 publications

(63 citation statements)

References 7 publications

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“…The temperature of the titration cell was maintained at 25.0 ± 0.1°C by an external circulating water bath. An inert atmosphere, Ar, was used to prevent the sorption of CO 2 electrode junction potential. Prior to each titration, an acid/base titration with standard HCl and NaOH was performed to calibrate the electrode, so that the EMF readings could be converted into the concentrations of the hydrogen ion in the subsequent titration.…”

Section: Methodsmentioning

confidence: 99%

Structural and Thermodynamic Study of the Complexes of Nd(III) with N,N,N′,N′-Tetramethyl-3-oxa-glutaramide and the Acid Analogues

2014

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The thermodynamics of Nd(III) complexes with N,N,N',N'-tetramethyl-3-oxa-glutaramide (TMOGA, L(I)), N,N-dimethyl-3-oxa-glutaramic acid (DMOGA, HL(II)), and oxydiacetic acid (ODA, H2L(III)) in aqueous solutions was studied. Stability constants, enthalpies, and entropies of complexation were determined by spectrophotometry, potentiometry, and calorimetry. The stability constants of corresponding Nd(III) complexes decrease in the following order: Nd(III)/L(III) > Nd(III)/L(II) > Nd(III)/L(I). For all complexes, the enthalpies of complexation are negative and the entropies of complexation are positive, indicating that the complexation is driven by both enthalpy and entropy. Furthermore, from L(III) to L(II), and to L(I), the enthalpy of complexation becomes more exothermic and the entropy of complexation less positive, suggesting that the substitution of a carboxylate group with an amide group on the ligands enhances the enthalpy-driven force but weakens the entropy-driven force of the complexation with Nd(III). Crystal structures of three 1:3 Nd(III) complexes, Nd(L(I))3(ClO4)3 (I), Nd(L(I))3(NO3)3(H2O)2 (II), and Nd(L(II))3(H2O)7.5 (III), were determined by single-crystal X-ray diffraction and compared with the structure of a 1:3 Nd(III)/L(III) complex in the literature, Na3NdL(III)3(NaClO4)2(H2O)6 (IV). In all four structures, the ligands are tridentate and Nd(III) is nine-coordinated with similar distorted tricapped trigonal prism geometry by three ether oxygen atoms capped on the three faces of the prism, and six oxygen atoms from the ketone group or carboxyl group at the corners. The absorption spectra of Nd(III) in solutions showed very similar patterns as Nd(III) formed successive 1:1, 1:2, and 1:3 complexes with L(I), L(II), and L(III), respectively, implying that the Nd(III) complexes with the three ligands have similar coordination geometries in aqueous solutions, as observed in the solids.

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Section: Methodsmentioning

confidence: 99%

Structural and Thermodynamic Study of the Complexes of Nd(III) with N,N,N′,N′-Tetramethyl-3-oxa-glutaramide and the Acid Analogues

2014

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“…[4][5][6][7][8][9][10] The amide ligands consist of only C, H, O and N atoms so that they are completely incinerable. As a result, the amount of solid radioactive wastes generated in the amide-based processes could be significantly reduced.…”

Section: Introductionmentioning

confidence: 99%

Thermodynamics, Optical Properties, and Coordination Modes of Np(V) with Dipicolinic Acid

2009

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Complexation of NpO 2+ with dipicolinic acid (DPA) has been investigated in 1 M NaClO 4 at 25ºC. Two complexes, NpO 2 (DPA) -and NpO 2 (DPA) 2 3-, were identified and the stability constants (logβ 1 and logβ 2 ) were determined to be 8.68 and 12.31 by spectrophotometry. The enthalpies of the complexation (ΔH 1 and ΔH 2 ) were measured to be -25.2 and -45.9 kJ/mol by microcalorimetry. The entropies (ΔS 1 and ΔS 2 ) were calculated to be 81.6 and 81.8 J/(K⋅mol) accordingly. The strong complexation of NpO 2 + with DPA is driven by both positive entropies and highly exothermic enthalpies.The crystal structure of Na 3 NpO 2 (DPA) 2 (H 2 O) 6 (s) shows that, in the NpO 2 (DPA) 2 3-complex, the Np atom sits at a center of inversion and the two DPA ligands symmetrically coordinate to Np in a tridentate mode. Due to the centrosymmetric structure of the NpO 2 (DPA) 2 3-complex, the f→f transitions of Np(V) are forbidden, and the sharp bands originating from the f→f transitions either 1 disappear or become very weak in the optical absorption or diffuse reflectance spectra of the NpO 2 (DPA) 2 3-complex.

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“…This can possibly lead to the contamination of the product and may require additional decontamination steps. Separation of trivalent actinides from Sr(II) using TODGA has been reported by Suzuki et al [13], who have used higher concentration of nitric acid for the decontamination of the extracted Am 3+ . However, use of higher concentration of nitric acid can lead to formation of certain undesirable nitro compounds.…”

Section: Introductionmentioning

confidence: 93%

Supported liquid membrane transport studies on Am(III), Pu(IV), U(VI) and Sr(II) using irradiated TODGA

Panja

Mohapatra

Tripathi

et al. 2012

Journal of Hazardous Materials

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Extraction and separation of Am(III) and Sr(II) by N,N,N´,N´-tetraoctyl-3-oxapentanediamide (TODGA)

Cited by 92 publications

References 7 publications

Structural and Thermodynamic Study of the Complexes of Nd(III) with N,N,N′,N′-Tetramethyl-3-oxa-glutaramide and the Acid Analogues

Structural and Thermodynamic Study of the Complexes of Nd(III) with N,N,N′,N′-Tetramethyl-3-oxa-glutaramide and the Acid Analogues

Thermodynamics, Optical Properties, and Coordination Modes of Np(V) with Dipicolinic Acid

Supported liquid membrane transport studies on Am(III), Pu(IV), U(VI) and Sr(II) using irradiated TODGA

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