Determination of Successive Complexation Constants in an Ionic Liquid: Complexation of UO22+ with NO3− in C4-mimTf2N Studied by UV−Vis Spectroscopy

Georg, Sylvia; Billard, Isabelle; Ouadi, Ali; Gaillard, C.; Petitjean, Laetitia; Picquet, Michel; Соловьев, В.П.

doi:10.1021/jp9107624

Cited by 59 publications

(58 citation statements)

References 43 publications

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“…[34] Under these chemical conditions, the transfer of C 5 mim + into the aqueous acidic phase rises by af actor of about three for TBP concentrations between 0.25 and 1.1 m. [30] It is, thus, important to quantify the IL solubility in the aqueous phase during the extraction process, as we have done in this paper.W ea lso present new experiments to characterize the extracted species in situ by combining UV/Vis and X-ray absorption (EXAFS) spectroscopy.T hese data allow us to refine our chemical model explainingt he mechanism of extraction of uranyl by the TBP/[C 4 3 ]h ave been reported in Ref. [35]]. T he other chemical reagents used, tri-n-butyl phosphate, concentrated nitric acid, sodium trifluoroacetate, sodium citrate, deuterated nitric acid, and deuterium oxide were of analytical grade.…”

Section: Introductionmentioning

confidence: 82%

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Insights into the Mechanism of Extraction of Uranium (VI) from Nitric Acid Solution into an Ionic Liquid by using Tri‐n‐butyl phosphate

et al. 2015

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We present new results on the liquid-liquid extraction of uranium (VI) from a nitric acid aqueous phase into a tri-n-butyl phosphate/1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (TBP/[C4 mim][Tf2 N]) phase. The individual solubilities of the ionic-liquid ions in the upper part of the biphasic system are measured over the whole acidic range and as a function of the TBP concentration. New insights into the extraction mechanism are obtained through the in situ characterization of the extracted uranyl complexes by coupling UV/Vis and extended X-ray absorption fine structure (EXAFS) spectroscopy. We propose a chemical model to explain uranium (VI) extraction that describes the data through a fit of the uranyl distribution ratio DU . In this model, at low acid concentrations uranium (VI) is extracted as the cationic complex [UO2 (TBP)2 ](2+) , by an exchange with one proton and one C4 mim(+) . At high acid concentrations, the extraction proceeds through a cationic exchange between [UO2 (NO3 )(HNO3 )(TBP)2 ](+) and one C4 mim(+) . As a consequence of this mechanism, the variation of DU as a function of TBP concentration depends on the C4 mim(+) concentration in the aqueous phase. This explains why noninteger values are often derived by analysis of DU versus [TBP] plots to determine the number of TBP molecules involved in the extraction of uranyl in an ionic-liquid phase.

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Section: Introductionmentioning

confidence: 82%

“…[35] Mixing the initial acidic aqueous phases with the chosen RTIL phases always led to biphasic systems (i.e. the meniscus is clearly visible).…”

Section: Sample Preparationmentioning

confidence: 99%

Insights into the Mechanism of Extraction of Uranium (VI) from Nitric Acid Solution into an Ionic Liquid by using Tri‐n‐butyl phosphate

et al. 2015

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“…All chemical reagents were used as received without any further purication. 35 N,N 0 -Dimethyl-N,N 0 -dibutylmalonamide (DMDBMA) was prepared and characterized according to the published method. 34 The other chemical reagents used, 1,2-dichloroethane, concentrated nitric acid, sodium triuoroacetate, sodium citrate, deuterated nitric acid and deuterium oxide were of analytical grade.…”

Section: Chemicalsmentioning

confidence: 99%

Ionic liquid-based uranium(vi) extraction with malonamide extractant: cation exchange vs. neutral extraction

et al. 2016

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“…12,33 Formation of uranyl speciations (coordinated anions) in such IL systems appeared to be controlled. The results from experiments 26,40,41 and calculations 42,43 (6), 3TT, and 3TG, as observed in interionic interactions, are discussed in relation to the different cations and temperatures. Additionally, novel transformations were observed with multiple characterizations of compounds 2, 3TT, 3TG, and 6.…”

Section: ■ Introductionmentioning

confidence: 91%

Crystallization in Ionic Liquids: Synthesis, Properties, and Polymorphs of Uranyl Salts

Liu

2014

Crystal Growth & Design

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Crystallizations in uranyl-containing ionic liquids yielding crystals {X} a {[UO 2 ] b [Y] c } with selected anions and cations (X = [Bmim] + for Y = Cl − , NO 3 − , and SCN − ; Y = Cl − for X = [Emim] + , [Emmim] + , [Bmim] + , and [Bmmim] + ;Emim = l-ethyl-3-methyl-imidazolium, Emmim = l-ethyl-2,3-dimethylimidazolium, Bmim = l-butyl-3-methylimidazolium, and Bmmim = l-butyl-2,3-dimethylimidazolium) were performed herein. Through standard crystallographic analyses, Hirshfeld surface analyses, and multiple characterization techniques, compounds with common cations/anions were investigated. For compounds [Bmim] 2 [(UO 2 ) 2 (μ-OH) 2 (NO 3 ) 4 ] (1), [Bmim] 3 [UO 2 (NCS) 5 ] (2), and [Bmim] 2 [UO 2 Cl 4 ] (3TT and 3TG), common [Bmim] + cations with different conformations were studied with respect to packing and interactions (for 1). The coordinated [(UO 2 ) 2 (μ-OH) 2 (NO 3 ) 4 ] 2− , [UO 2 (NCS) 5 ] 3− , and [UO 2 Cl 4 ] 2− anions that have historically been related to nuclear fuel cycles were demonstrated with respect to geometry and distortion. For compounds with common [UO 2 Cl 4 ] 2− anions [Emim] 2 [UO 2 Cl 4 ] (4), [Emmim] 2 [UO 2 Cl 4 ] (5), [Bmmim] 2 [UO 2 Cl 4 ] (6), 3TT, and 3TG, observed interionic interactions that have been previously impeded by limited structural information were discussed fully in relation to different cations and temperatures. Moreover, multistep phase transformations of 2, which have been undefined in solution studies, have been identified through differential scanning calorimetry analyses and polarizing optical microscopy. The polymorph transformations between 3TT and 3TG in solution, as controlled by uranyl concentration, were studied using optical microscopy and powder X-ray diffraction. The thermal stability, IR/Raman, and UV−vis/luminescence spectra of these compounds were also investigated. ■ INTRODUCTIONIonic liquids (ILs) are attractive to investigators due to their unique physical and chemical properties and have thus been widely examined in many areas. 1,2 Among their usages, crystallization in ILs is a complex and fascinating field of research. 3−5 Both the unique coordination features that cannot generally be observed using molecular solvents and the interaction specifics that are difficult to obtain in the liquid state of ILs can be investigated. 6,7 However, the crystallography data that have immensely promoted our understanding of intermolecular interactions 8 have not been fully explored regarding the crystallographic potential in IL systems.A special interest in f metal-containing ILs has recently arisen in various fields, resulting in many high-quality investigations involving crystallographic studies. 9−12 Specifically, promising applications of ILs in nuclear fuel cycles 13−17 have encouraged extensive studies on uranium-based IL systems, including the relatively common crystallization of uranium salts in ILs and novel explorations of crystallization methods in such complex systems. [3][4][5][6]13,18,19 Using the widely studied uranyl-imidazolium structures as...

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Determination of Successive Complexation Constants in an Ionic Liquid: Complexation of UO₂²⁺ with NO₃⁻ in C₄-mimTf₂N Studied by UV−Vis Spectroscopy

Cited by 59 publications

References 43 publications

Insights into the Mechanism of Extraction of Uranium (VI) from Nitric Acid Solution into an Ionic Liquid by using Tri‐n‐butyl phosphate

Insights into the Mechanism of Extraction of Uranium (VI) from Nitric Acid Solution into an Ionic Liquid by using Tri‐n‐butyl phosphate

Ionic liquid-based uranium(vi) extraction with malonamide extractant: cation exchange vs. neutral extraction

Crystallization in Ionic Liquids: Synthesis, Properties, and Polymorphs of Uranyl Salts

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