N-oxide ligands for selective separations of lanthanides: insights from computation

Liu, Tongyu; Ivanov, Alexander S.; Popovs, Ilja; Jansone‐Popova, Santa; Jiang, De‐en

doi:10.1039/d2ra07029d

Cited by 5 publications

(22 citation statements)

References 37 publications

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“…The FTIR spectra of neat and regenerated IL are almost identical (Figure S5). In the 13 C and 1 H NMR spectra (Figure 2), no residual acetic acid and acetonitrile was found in the regenerated IL. Generally, the proton signal of acetic acid lies between 10 and 15 ppm, and that of acetonitrile near 2 ppm [52,53].…”

Section: Regeneration Of the Reacted Ionic Liquidmentioning

confidence: 99%

“…The samples were dissolved in deuterated DMSO-d6 and filled in an NMR tube. Measurements were performed on a Bruker Avance (Leipzig, Germany) Neo WB 300 MHz NMR spectrometer at resonance frequencies of 300 MHz for 1 H and 75.5 MHz for 13 C spectra. The chemical shifts were referenced externally according to tetramethylsilane (TMS) and were calibrated with 10% ethylbenzene in CDCl 3 as external reference.…”

Section: Synthesis Of [Bdmim][oac]mentioning

confidence: 99%

“…No solid residue remained after combustion of the regenerated IL in air. The 13 C NMR spectra of regenerated and neat IL showed no difference as long as the freshly regenerated IL was stored under inert conditions (sample A). After some time in air (sample B), the 1 H NMR spectrum of the regenerated IL showed a broad resonance signal at 5 ppm, which can be attributed to H2O, and also an up-field shift of the protons at C 2 , C 4 , and C 5 .…”

Section: Regeneration Of the Reacted Ionic Liquidmentioning

confidence: 99%

“…Super-acidic ILs combined with a stream of chlorine gas also dissolve rare-earth oxides [11]; however, using a highly toxic gas does not achieve the aim of green chemistry. Nevertheless, there are also some existing reports on the direct dissolution of rare-earth oxides in ILs [12][13][14][15][16][17]. Water-stable ILs containing Brønsted acidic groups, in particular the very effective IL [Hbet][NTf 2 ] ([Hbet] + = betainium, [NTf 2 ] − = bis(trifluoromethylsulfonyl)imide), are much more suitable.…”

Section: Introductionmentioning

confidence: 99%

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Reactivity of Rare-Earth Oxides in Anhydrous Imidazolium Acetate Ionic Liquids

et al. 2023

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Rare-earth metal sesquioxides (RE2O3) are stable compounds that require high activation energies in solid-state reactions or strong acids for dissolution in aqueous media. Alternatively, dissolution and downstream chemistry of RE2O3 have been achieved with ionic liquids (ILs), but typically with additional water. In contrast, the anhydrous IL 1-butyl-3-methylimidazolium acetate [BMIm][OAc] dissolves RE2O3 for RE = La–Ho and forms homoleptic dinuclear metal complexes that crystallize as [BMIm]2[RE2(OAc)8] salts. Chloride ions promote the dissolution without being included in the compounds. Since the lattice energy of RE2O3 increases with decreasing size of the RE3+ cation, Ho2O3 dissolves very slowly, while the sesquioxides with even smaller cations appear to be inert under the applied conditions. The Sm and Eu complex salts show blue and red photoluminescence and Van Vleck paramagnetism. The proton source for the dissolution is the imidazolium cation. Abstraction of the acidic proton at the C2-atom yields an N-heterocyclic carbene (imidazole-2-ylidene). The IL can be regenerated by subsequent reaction with acetic acid. In the overall process, RE2O3 is dissolved by anhydrous acetic acid, a reaction that does not proceed directly.

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Section: Regeneration Of the Reacted Ionic Liquidmentioning

confidence: 99%

Section: Synthesis Of [Bdmim][oac]mentioning

confidence: 99%

Section: Regeneration Of the Reacted Ionic Liquidmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Reactivity of Rare-Earth Oxides in Anhydrous Imidazolium Acetate Ionic Liquids

et al. 2023

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“…In contrast to a large number of reports available in the literature, which target the selective separation of trivalent actinides over lanthanides utilizing several N donor or S donor ligands, − attempts have been made to use mixed donor ligands containing O and N atoms for enhanced selectivity of actinides over lanthanides. − It is anticipated that the cooperative complexation of multifunctional ligands can be far more efficient than the ligands containing one ligating site. In this context, nitrilotriacetamide (NTAamide, Figure ) ligands, having both >CO oxygen atoms and a central nitrogen atom, have been investigated for their selective complexation and extraction of trivalent actinides over lanthanides. , Initial studies with N,N,N′,N′,N″,N″ -hexa- n -octyl nitrilotriacetamide (HONTA) as the extractant have shown that Am 3+ is 23.6 times more extracted than the lanthanides .…”

Section: Introductionmentioning

confidence: 99%

Understanding the Complexation of Alkyl-Substituted Nitrilotriacetamides with Uranium: A Study by Absorption Spectroscopy and Microcalorimetry

Ansari,

Bhattacharyya,

Mohapatra

et al. 2024

Inorg. Chem.

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Complexation thermodynamics of UO 2 2+ ions with a series of alkyl-substituted nitrilotriacetamides (NTA) was investigated by absorption spectroscopy and microcalorimetry. The hexamethyl derivative of NTA (HMNTA) forms the weakest two successive complexes with UO 2 2+ ions with stability constants of log β 11 = 3.5 ± 0.1 and log β 12 = 6.1 ± 0.1. The formation constant values increased linearly with increasing alkyl chain length of the substituents from hexamethyl NTA to hexabutyl NTA (HBNTA) and to hexahexyl NTA (HHNTA). The complexation with each ligand was both enthalpy and entropy driven with exothermic enthalpy changes of ΔH 11 = −14.7 ± 1.0 kJ/mol, ΔH 12 = −10.2 ± 0.8 kJ/mol for HMNTA, ΔH 11 = −19.2 ± 1.2 kJ/mol, ΔH 12 = −16.4 ± 1.1 kJ/mol for HBNTA, and ΔH 11 = −21.3 ± 1.4 kJ/mol, ΔH 12 = −19.4 ± 2.3 kJ/mol for HHNTA. Similarly, the positive entropy changes with each ligand were ΔS 11 = 18.1 ± 2.7 J/mol/K, ΔS 12 = 82.9 ± 3.8 J/mol/K for HMNTA, ΔS 11 = 14.4 ± 1.2 J/mol/K, ΔS 12 = 87.2 ± 4.2 J/mol/K for HBNTA, and ΔS 11 = 16.1 ± 2.4 J/mol/K, ΔS 12 = 92.6 ± 3.1 J/mol/K for HHNTA. Structural features of the complex suggest the participation of two ligands coordinating in a bidentate mode via the carbonyl oxygens. The [UO 2 L 2 ] 2+ complexes appear to be noncentrosymmetric with two ligands and one water molecule occupying the equatorial plane of the dioxo uranyl cation. The structure of the complex was confirmed by 1 H NMR titration, EXAFS measurements, and DFT calculations.

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Artificial Intelligence Models for Efficiency Estimation of Adsorbents in Rare-Earth Element Recovery Based on Feature Engineering

Bashiri,

Habibi,

Sufali

et al. 2024

Ind. Eng. Chem. Res.

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Efficiently separating rare-earth elements (REEs) remains a significant challenge due to selectivity, costs, and potential environmental pollution. This research presents an innovative approach to the efficiency of adsorbents in REE recovery from contaminated water based on feature engineering using machine-learning algorithms and the RDKit toolkit. By analyzing a comprehensive data set from experimental articles, the influential features of promising adsorbents were optimized. The importance of each input feature on the target label (Q ad ) reveals that the molecular weight of the first functional group significantly impacts adsorption efficiency. The study delves into electron configurations, atomic properties, and thermodynamics, emphasizing the need for balanced energy states, binding affinities, and various bonding mechanisms at play. This accurate model (R 2 values of 0.928 for both training and testing) provides valuable insights into estimating adsorbent efficiency for REE recovery, paving the way for sustainable materials and promoting novel adsorbent practices in the industry.

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N-oxide ligands for selective separations of lanthanides: insights from computation

Abstract: N-oxide ligands, combined with pyridinic N groups, are predicted to offer attractive La(iii)/Ln(iii) selectivities for rare-earth separations.

Cited by 5 publications

References 37 publications

Reactivity of Rare-Earth Oxides in Anhydrous Imidazolium Acetate Ionic Liquids

Reactivity of Rare-Earth Oxides in Anhydrous Imidazolium Acetate Ionic Liquids

Understanding the Complexation of Alkyl-Substituted Nitrilotriacetamides with Uranium: A Study by Absorption Spectroscopy and Microcalorimetry

Artificial Intelligence Models for Efficiency Estimation of Adsorbents in Rare-Earth Element Recovery Based on Feature Engineering

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