Extraction of Various Metal Ions from Nitric Acid to<i>n</i>-dodecanen by Diglycolamide (DGA) Compounds

Sasaki, Yoshiyuki; Zhixuan, Zhu; Sugo, Yumi; Kimura, Takaumi

doi:10.1080/18811248.2007.9711301

Cited by 63 publications

(11 citation statements)

References 9 publications

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“…On the basis of the N,N,N′,N ′-tetraoctyl diglycolamide (TODGA) aggregate formation being the sole reason for the reversal in the extraction trend, it is clear that three to four TODGA molecules are associated in the formation of a reverse micelle in nonpolar diluents such as n -dodecane when contacted with dilute nitric acid. The core of such a reverse micelle shows preferential affinity for trivalent actinides (also for lanthanides) in a size-selective manner . Taking the clue from this, it was predicted that preorganization of 3–4 DGA molecules on a molecular platform would enhance the affinity of these ligands for trivalent f-cations.…”

Section: Introductionmentioning

confidence: 99%

Highly Efficient N-Pivot Tripodal Diglycolamide Ligands for Trivalent f-Cations: Synthesis, Extraction, Spectroscopy, and Density Functional Theory Studies

et al. 2019

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A series of four N-pivot tripodal diglycolamide (DGA) ligands, where three DGA moieties are attached to the central N atom via spacers of different lengths and with varying alkyl substituents on the amidic nitrogen of DGA (L I −L IV ), were studied for their extraction and complexation ability toward trivalent lanthanide/actinide ions, including solvent extraction, complexation using spectrophotometric titrations, and luminescence spectroscopic studies. Introduction of a methyl group on the amidic nitrogen atom gives rise to a 400 fold increase of the Eu distribution (D) value [L III (NMe) vs L II (NH)] at 1 M HNO 3 . Enlargement of the spacer length between the pivotal N atom and the DGA moieties with one carbon atom results in a 14 times higher D Eu value [L I (C3) vs L II (C2)]. Slope analyses showed that Eu 3+ was extracted as a bis-solvated species with all four ligands. The compositions of the Eu 3+ /L complexes were further confirmed by spectroscopic measurements, its formation constants following the order: L III > L IV > L I > L II . Luminescence spectroscopy and electrospray ionization mass spectrometry revealed that all four ligands form [Eu(L) 2 (NO 3 ) 3 ] complexes. Density functional theory and thermodynamic parameters corroborated the existence of [Eu(L) 2 (NO 3 ) 3 ] complexes.

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Section: Introductionmentioning

confidence: 99%

Highly Efficient N-Pivot Tripodal Diglycolamide Ligands for Trivalent f-Cations: Synthesis, Extraction, Spectroscopy, and Density Functional Theory Studies

et al. 2019

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“…Suzuki and co-workers applied the difference in the metal ion recognition capabilities of the reagents to separate Am(III) from Cm(III) The combination of two different diamide-type reagents, namely, alkyl diamide amine (ADAAM) and diglycolamide (DGA), shown in Figure , allowed for Am(III) selectivity over Cm(III) with high separation factor of 41 . Sasaki et al achieved high selectivity for f-block metal ions compared to the other softer metal ions, indicating that DGA reagents work as hard-donor ligands . The previous study also implied that ADAAM reagent works as soft-donor ligand owing to its Am(III) selectivity over Eu(III) with a separation factor of 25 .…”

Section: Introductionmentioning

confidence: 95%

Theoretical Elucidation of Am(III)/Cm(III) Separation Mechanism with Diamide-type Ligands Using Relativistic Density Functional Theory Calculation

2018

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We elucidated the separation mechanism between Am(III) and Cm(III) ions by using two different types of diamide ligands, diglycolamide (DGA) and alkylated diamide amine (ADAAM), by means of the density functional theory technique and electron density analysis. The molecular geometries and formation reactions of the metal–ligand complexes were modeled by using [M(DGA)3]3+ and [M(ADAAM)(NO3)3(H2O)]. We successfully reproduced Cm(III) selectivity over Am(III) with DGA and Am(III) selectivity over Cm(III) with ADAAM. Furthermore, we analyzed the bonding properties between the metal ion and the diamide-type ligands by using model complexes, [M(DGA)3]3+ and [M(ADAAM)(NO3)3(H2O)], and revealed the differences in terms of the bond dissociation energy and the metal 5f orbital participation in the covalency between the Am(III) and the Cm(III) complexes. It was suggested that the differences were key factors to understand the Am(III)/Cm(III) selectivity.

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“…Various modifiers have been tried (e.g. tri-butyl phosphate [ [23][24], lipophilic alcohols [ [25][26], monoamides [27][28][29], DMDOHEMA (N,N'-dimethyl-N,N'-dioctyl-2-(2-hexyloxy-ethyl)malonamide) [ [30][31]). A solvent comprising 0.2 mol/L TODGA with 5 v/v% octanol in an inert diluent such as odourless kerosene or hydrogenated tetra propylene (TPH) has been developed [ 32 ] and used [ 14 ] in recent European research programmes.…”

Section: Figure 1: Nnn'n'-tetra-n-octyl Diglycolamide (Todga)mentioning

confidence: 99%

Nitric Acid Extraction into a TODGA Solvent Modified with 1-Octanol

Woodhead

McLachlan

Taylor

et al. 2019

Solvent Extraction and Ion Exchange

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Distribution data for the partition of nitric acid between nitric acid solution and a solvent phase comprising various combinations of TODGA, octanol and inert kerosene diluent have been generated, covering a range of conditions from 0-9 mol/L HNO3(aq), 0-100% octanol, 0-0.4 mol/L TODGA over a temperature range from 10-50 °C. The data have been used to derive a model describing the nitric acid equilibrium between the phases suitable for incorporation in process models of e.g. the innovative SANEX process. For the nitric acid / octanol / diluent system it was found that an accurate prediction of nitric acid distribution could be achieved using a model allowing 1:1, 1:2 and 1:3 nitric acid / octanol adducts. For the nitric acid / TODGA / diluent system the best models were found to be those allowing 4:1, 3:1, 2:1, 1:1 and 2:2 nitric acid / TODGA adducts. Superimposing the models for nitric acid distribution into the individual extractants and comparing with experimental results for the nitric acid / octanol / TODGA system showed systematic differences indicative of antagonistic and synergistic effects applying in the ranges 0.5-1.5 mol/L HNO3 and > 1.5 mol/L HNO3 respectively. These effects were modelled by the inclusion of 0:1:2, 1:1:1, 2:1:3 and 3:1:2 nitric acid / TODGA / octanol adducts. The effect of temperature on nitric acid extraction was well described by an Arrhenius type expression with an activation energy of −25.7 kJ/mol. No diluent dependence was found for nitric acid extraction.

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Extraction of Various Metal Ions from Nitric Acid ton-dodecanen by Diglycolamide (DGA) Compounds

Cited by 63 publications

References 9 publications

Highly Efficient N-Pivot Tripodal Diglycolamide Ligands for Trivalent f-Cations: Synthesis, Extraction, Spectroscopy, and Density Functional Theory Studies

Highly Efficient N-Pivot Tripodal Diglycolamide Ligands for Trivalent f-Cations: Synthesis, Extraction, Spectroscopy, and Density Functional Theory Studies

Theoretical Elucidation of Am(III)/Cm(III) Separation Mechanism with Diamide-type Ligands Using Relativistic Density Functional Theory Calculation

Nitric Acid Extraction into a TODGA Solvent Modified with 1-Octanol

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