The extraction of lanthanides(III) from aqueous nitric acid solutions with tetra(n-octyl)diglycolamide into trioctylammonium di-2-ethylhexylsulfosuccinate ([N888H][SSu]) ionic liquid and its mixtures with molecular organic diluents is studied. It is showed that the efficiency and selectivity of the Ln(III) extraction from nitric acid solutions with TODGA into [N888H][SSu] is significantly higher than when using 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide IL [C4mim][Tf2N] as a diluent. Additionally, in the system with [N888H][SSu], the transfer of SSu- ions into the aqueous phase occurs to a much lesser extent than the transfer of Tf2N- in systems with [C4mim][Tf2N]. It is established that the efficiency of extraction of Ln(III) ions with TODGA increases significantly when [N888H][SSu] is added to the organic phase. The synergistic effect arises due to the higher hydrophobicity of the extractable Ln(III) complexes formed by the TODGA ligand and di-2-ethylhexylsulfosuccinate anions compared to those containing NO3- ions as counterions. The stoichiometry of the extracted complexes is determined, and the influence of the composition of the aqueous phase, and the nature of the organic solvent on the efficiency of the Ln(III) extraction into the organic phase is considered.

The efficiency of the extraction of lanthanide(III), americium(III), and thorium(IV) ions from nitric acid solutions with tetraoctyldiglycolamide significantly increases in the presence of an ionic liquid, didecylammonium di-2-ethylhexyl sulfosuccinate, in the organic phase. The effect of the aqueous phase acidity on the distribution ratios of the extracted elements was considered, and the stoichiometry of the extractable complexes was determined.

The extraction of U(VI), Th(IV), Am(III), and Eu(III) with solutions of phosphorylated pyridines from nitric acid solutions has been studied. The stoichiometry of the extractable complexes was established. In terms of their extraction ability, these compounds are inferior to bis(diphenylphosphinyl)methane, but they are significantly superior to carbamoylmethylphosphine oxides. An increase in the number of phosphine oxide groups in the molecules of phosphorylated pyridines leads to a significant decrease in their extraction ability and selectivity in the extraction of Am(III) and Eu(III) from nitric acid solutions.

The extraction of lanthanides(III) from aqueous nitric acid solutions with novel unsymmetrical diglycolamide extactant, N,N′-dimethyl-N,N′-dicyclohexyldiglycolamide (DMDCHDGA) into bis(trifluoromethylsulfoyl)imide-based ionic liquids (ILs), namely 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([C4mim][Tf2N]), 1-octyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([C8mim][Tf2N]), benzyltriethylammonium bis(trifluoromethylsulfonyl)imide ([N222Bn][Tf2N]) methyltrioctylammonium bis(trifluoromethylsulfonyl)imide ([N1888][Tf2N]), and their mixtures with molecular organic diluent 1,2-dichloroethane (DCE), is studied. DMDCHDGA has been shown to interact with components of the IL [C4mim][Tf2N]. The effect of HNO3 concentration in the aqueous phase on the extraction of Ln(III) ions is studied. The stoichiometry of the extracted complexes is determined, and the mechanism of Ln(III) extraction in a system with [C4mim][Tf2N] is discussed. It is shown that the efficiency and intragroup selectivity of the extraction of Ln(III) ions with DMDCHDGA into [C4mim][Tf2N] is significantly higher than when using its symmetric analog TODGA.

It was found that the extraction of lanthanides(III) from nitric acid solutions with solutions of carbamoylmethylphosphine oxides increases significantly in the presence of dinonylnaphthalene sulfonic acid. The stoichiometry of the extracted complexes was determined, and the influence of the composition of the aqueous phase, the nature of the organic solvent, and the structure of carbamoylmethylphosphine oxides on the efficiency of extraction of metal ions into the organic phase was considered.

The coordination and extraction properties of two related tripodal ligands differed by types of addition of the triazole fragment and linker length in the 2-[(4-Ph-1,2,3-triazol-1-yl)CH2CH2O]C6H43P(O) (L1) and 2-[(1-Ph-1,2,3-triazol-4-yl)CH2O]C6H43P(O) (L2) are compared. The structures of the complexes [Lа(NO3)3L1] (I) and [Lu(NO3)3L1] (II) are studied in the solid phase (elemental analysis, IR and Raman spectroscopy) and in solutions (IR and multinuclear 1H, 13C, and 31P NMR spectroscopy). A normal coordinate analysis at the TPSS-D4/Def2-SVP level is performed for an isolated molecule of the model complex [LaP(O),N3,N2-L3(O,O-NO3)3] (L3 = 2-[(4-Me-1,2,3-triazol-1-yl)CH2CH2O]C6H43-P(O)). According to the set of spectral and quantum chemical data, ligand L1 exhibits the tridentate P(O),N2,N2 coordination in lanthanide complexes I and II. These are neutral complexes in the solid state and in CD3CN solutions, and the dynamic equilibrium of the neutral and ionic complexes is observed in CDCl3. Unlike ligand L1, ligand L2 exhibits the tetradentate P(O),N3,N3,N3 coordination in the [Ln(NO3)3L2] complexes with the same metals (Ln = La3+, Lu3+) in solutions. The efficiency of extraction of microquantities of f elements from the aqueous phase to 1,2-dichloroethane by compounds L1 and L2 is discussed in comparison with the structures of the complexes of both ligands in solutions.

The effect of the ionic liquid, 1-butyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide, on the extraction of lanthanides(III) from nitric acid solutions with phosphoryl-containing podands (2-(2-diphenylphosphoryl)-4-ethylphenoxy)methyl)diphenylphosphine oxide (1), (2-(2-diphenylphosphoryl)-4-ethylphenoxy)ethyl)diphenylphosphine oxide (2), and 2-[2-(diphenylphosphoryl)-4-ethylphenoxy]-N,N-dioctylacetamide (3) was studied. The stoichiometry of the extracted complexes was determined. The efficiency of extraction of lanthanides(III) with solutions of compounds 1–3 in dichloroethane from nitric acid solutions increases in the order 3 < 2 < 1. It has been established that, when replacing dichloroethane with an ionic liquid as a diluent, the extraction efficiency enhances. The magnitude of this effect decreases in the series of compounds 3 > 2 > 1. In the case of compound 1, the replacement of dichloroethane with an ionic liquid as a solvent is accompanied by a decrease in the extraction of lanthanides(III) at [HNO3] > 1.5 M.

The interphase distribution of lanthanide(III) ions between aqueous solutions of HNO3 and solutions of tetrabutyldiglicolamide Bu2C(O)CH2OCH2C(O)NBu2 (1), compounds R2P(O)CH2OCH2C(O)NBu2, where R = Bu (2), R = Ph (3) and phosphoryl-containing podands R2P(O)CH2OCH2P(O)R-2(1), where R = R-1 = Bu (4); R = Bu, R-1 = Ph (5); R = R-1 = Ph (6) in 1,2-dichloroethane and ionic liquid-1-butyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide-has been studied. Extraction of metal ions has been found to increase considerably in the presence of ionic liquid in organic phase. The stoichiometry of the extracted complexes has been determined and the influence of HNO3 concentration in aqueous phase and the structure of the extractant on the efficiency of metal ions extraction into organic phase has been considered.

Effect of ionic liquid 1-butyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide on the extraction of U(VI), Th(IV), and lanthanides(III) from nitric acid solutions with phosphorylureas RR'P(O)NHC(O)NHC8H17-n that differ in the nature of substituents at the phosphorus atom has been studied. A considerable synergistic effect has been revealed on the extraction of metal ions in the presence of the ionic liquid in organic phase. The stoichiometry of extracted complexes has been determined. The influence of extractant structure, organic diluent nature, and HNO3 concentration in aqueous phase on the efficiency of metal ions extraction into organic phase has been considered.

A new dicationic ionic liquid 1-methyl-3-(4-(tributylphosphonio)butyl)-1H-imidazol-3-ium di[bis(trifluoromethanesulfonul)imide] [ImP][Tf2N]2, characterized by high hydrophobicity (solubility in water 9.2 × 10-4 mol/l) was synthesized. The extraction of U(VI), Th(IV), and lanthanides(III) from nitric acid solutions with mixtures of 1,5-N,N’-bis[(diphenylphosphoryl)acety(hexyl)amino]pentane (L), containing two bidentate fragments Ph2P(O)CH2C(O)N(Hex)- interconnected by pentamethylene spacer through amide nitrogen atoms, and [ImP][Tf2N]2 in 1,2-dichloroethane (DCE) was studied. During the extraction of metal ions in this system, a significant synergistic effect is observed. The influence of the composition of the aqueous and organic phases on the efficiency of the extraction of metal ions into the organic phase is considered, and the stoichiometry of the extracted complexes is determined. The synergistic effect at the extraction of Ln(III) from 3 M HNO3 solutions with a mixture of L and [ImP][Tf2N]2 in DCE is an order of magnitude higher than in the L–[C8mim][Tf2N]–DCE system.

The interphase distribution of microquantities of ReO4– between aqueous solutions of mineral acids and solutions of oligodentate β-aminophosphoryl compounds in organic solvents was studied. The stoichiometry of the extracted complexes was determined, the influence of the concentration of HClO4, HNO3, HCl and H2SO4 in the aqueous phase, the structure of the extractant and the nature of the organic solvent on the efficiency of the transition of ReO4– ions into the organic phase was considered. The possibility of selective extraction and concentration of Re(VII) with a complexing sorbent obtained by non-covalent attachment of tris[bis(2-diphenylphosphorylethyl)aminoethyl]amine on the surface of the macroporous polymer Amberlite XAD7HP was demonstrated.

The extraction of U(VI), Th(IV), Am(III), and lanthanides(III) from nitric acid solutions with solutions of phosphorylated pyrazines in organic solvents was studied. The stoichiometry of the extracted complexes was determined, and the influence of the structure of the extractant and an HNO3 concentration in the aqueous phase on the efficiency of the extraction of metal ions into the organic phase was considered. It was established that among the studied compounds, bis(diphenylphosphine)quinoxaline dioxide has the highest extraction ability with respect to actinides and lanthanides in nitric acid media.

The extraction of lanthanides(III) from aqueous nitric acid solutions with mixtures of bis(diphenylcarbamoylmethylphosphine oxides) (L) and dinonylnaphthalene sulfonic acid (HDNNS) in organic diluents is studied. It is established that the efficiency of extraction of Ln(III) ions increases significantly when HDNNS is added to the organic phase containing L. The synergistic effect arises due to the higher hydrophobicity of the extractable Ln(III) complexes formed by the L ligand and DNNS- anions compared to those containing NO3- ions as counteranions. The stoichiometry of the extracted complexes is determined, and the influence of the composition of the aqueous phase, the nature of the organic solvent, and the structure of the bis-CMPO ligands on the efficiency of the extraction of metal ions into the organic phase is considered. The synergistic effect during the extraction of Ln(III) from aqueous nitric acid solutions with mixtures of L and HDNNS weakens with increasing the acidity of the aqueous phase; however, it also holds in acidic media.

Extraction of U(VI), Th(IV), REE(III), and Sc(III) from nitrate and perchlorate solutions with solutions of phosphorylpodand 1,5-bis[di( p -tolyl)phosphoryl]-3-oxapentane (L) in 1,2-dichloroethane depending on the concentration of acids in the aqueous phase was studied. The stoichiometry of the extractable complexes was determined. The magnitude of the “perchlorate” effect was shown to diminish upon an increase in the acid concentration, and REE(III) ions, to be extracted by podand L from HClO 4 solutions less efficiently than from HNO 3 solutions at acid concentrations above 0.3 M. During the extraction of Sc(III) the “perchlorate” effect also manifests itself in the region of high acid concentration, which leads to an increase in the separation factors of Sc(III) and REE(III), U(VI), and Th(IV) during extraction with podand L from HClO 4 solutions.

The effect of the ionic liquid—1-butyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide—on the extraction of lanthanides(III), U(VI) and Th(IV) from nitric acid solutions with 1,2-bis(diphenylphosphinyl)-ethane I and 1,2-bis(diphenylphosphinyl)benzene II was studied. The stoichiometry of the extracted complexes was determined. A solution of dioxide II in dichloroethane extracts metal ions much more efficiently than a solution of dioxide I . It was established that in the presence of an ionic liquid in the organic phase, the efficiency of extraction of metal ions from nitrate solutions with solutions of dioxide I increases significantly, and that of dioxide II decreases. Thus, in the presence of an ionic liquid in the organic phase, dioxide II is significantly inferior to dioxide I in terms of the efficiency of Ln(III), U(VI) and Th(IV) extraction from nitric acid solutions, which is attributed to a significantly greater ability of dioxide II to extract HTf 2 N.

It has been found that the efficiency of extraction of lanthanide(III) ions from nitric acid solutions with 1,3-bis[(diphenylphosphorylacetamido)methyl]benzene significantly increases in the presence of ionic liquids, i.e., 1-alkyl-3-methylimidazolium di-2-ethylhexylsulfosuccinates, in an organic phase. The dependence of the partition of ionic liquids between the organic and aqueous phases has been studied on the ionic liquid and nitric acid concentrations. The stoichiometry of the extractable lanthanide(III) complexes has been evaluated by the equilibrium shift method. We have considered the influence of the length of alkyl radicals in the cationic part of the ionic liquid and the HNO 3 concentration in the aqueous phase on the efficiency of the extraction of metal ions into the ionic liquid-containing organic phase.

A method for the synthesis of 2-(3,4-diphenylphosphinylpyrrolidin-1-yl)ethanol and 3-(3,4-diphenylphosphinylpyrrolidin-1-yl)propanol was developed, and extraction of U(VI), Th(IV), and lanthanides(III) from nitric acid solutions was studied. The stoichiometry of the extracted complexes was determined, and the influence of the extractant structure and the HNO(3)concentration in the aqueous phase on the efficiency of extraction of the metal ions into the organic phase was evaluated. It was found that 2-(3,4-diphenylphosphinylpyrrolidin-1-yl)ethanol exhibits high extraction ability with respect to actinides and lanthanides in nitrate media.

The extraction of lanthanides(III) from aqueous nitric acid solutions with tetra(n-octyl)diglycolamide into methyltrioctylammonium bis(trifluoromethanesulfonul)imide ([N1888][Tf2N]) ionic liquid and its mixtures with molecular organic diluents is investigated in this study. This study also investigates the effect of HNO3 concentration in the aqueous phase on the extraction of Ln(III) ions. Subsequently, the stoichiometry of the extracted complexes is determined, and the mechanism of Ln(III) extraction in a system with [N1888][Tf2N] is discussed. It is shown that the intragroup selectivity of the extraction of Ln(III) ions is significantly higher when using [N1888][Tf2N] than when using the imidazolium-based ionic liquid [C4mim][Tf2N].

Congruent and stoichiometric ferroelectric lithium niobate-tantalate crystals LiNb(1-x)TaxO3 of different compositions were grown by the Czochralski method. The stoichiometric crystals were grown using the top seeded solution growth method using LiWO4, which increases the Li content in the melt and in the grown crystal. Also, the use of a solvent can significantly reduce the temperature of the melt. The composition of the crystals was studied by inductively coupled plasma mass spectrometry using laser ablation, which allow studying the change in the composition of the grown crystals along the length and diameter. It is demonstrated that the content of Ta in the crystals exceeds the content of Ta in the initial charge, i.e., in the process of crystal growth, the melt becomes depleted in Ta. It is shown that the Ta content decreases along the crystal length due to the decrease in the Ta content in the melt. In the LiNb0.88Ta0.12O3 crystals, the piezoelectric moduli d22 and d33, and the velocities of bulk and surface acoustic waves were measured. The values of piezoelectric moduli and acoustic wave velocities are shown to occupy an intermediate position between LiNbO3 and LiTaO3 crystals.

Considerable synergetic effect has been revealed on extraction of REE(III) ions from chloride solutions with mixtures of picrolonic acid and tris(diarylphosphoryl)-1,3,5-triazines in 1,2-dichloroethane due to formation of hydrophobic mixed-ligand REE(III) complexes. Parameters of extraction equilibrium and stoichiometry of resulting complexes have been determined. Effect of aqueous phase composition, organic solvent nature, and extractant structure has been studied. The largest synergetic effect has been observed in the system with tris(ditolylphosphoryl)-1,3,5-triazine.