Extraction properties of polyfunctional P,N-containing podands with diphenylphosphorylacetamide terminal groups in nitric acid solutions

The extraction of HNO₃ and microamounts of U(VI), Th(IV), Sc(III), and REE(III) nitrates from HNO₃ solutions with dichloroethane solutions of phosphorus-containing podands containing two terminal Ph₂P(O)CH₂C(O)NH groups linked by a di-or triethylene glycol chain was studied, and the stoichiometry of the extractable metal complexes was determined. The compounds extract the metal ions from nitric acid solutions more efficiently than does (dibutylcarbamoylmethyl)diphenylphosphine oxide. With increasing length of the polyethylene glycol chain, the extraction of HNO₃ increases, but the degree of recovery of REE(III) ions from HNO₃ solutions of the concentration exceeding 3 M decreases.     

Extraction of Rare-Earth Elements and Americium from Nitric Acid Solutions with Polyphosphine Oxides

Extraction of HNO₃ and microamounts of Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Am from solutions of NH₄NO₃ and HNO₃ with solutions of polyphosphine oxides containing o-oxyphenylenemethylene fragments in dichloroethane was studied. The stoichiometry of the extractable complexes was determined, and the apparent extraction constants were calculated. As the number of phosphoryl groups in the extractant molecule is increased, the extraction of cerium-group lanthanides increases and that of yttrium-group lanthanides decreases.     

Selectivity of extraction of U(VI), Th(IV), and REE(III) from perchloric acid solutions with bidentate phosphoryl-substituted butyl phenylphosphinates

Extraction of microamounts of U(VI), Th(IV), and REE(III) from HClO₄ solutions with solutions of bidentate phosphoryl-substituted butyl phenylphosphinates R₂P(O)CH₂P(O)Ph(OBu) [R = phenyl (I), octyl (II)] in dichloroethane was studied. The effect of substituents at the phosphorus atom in the phosphine oxide moiety of these compounds on their extraction ability and selectivity was examined, and the stoichiometry of the extractable complexes was determined. In going from nitric to perchloric acid solutions, the efficiency of the extraction of U(VI) and REE(III) considerably increases, the U/REE separation factors increase, but the Th/U separation factors decrease.     

Extraction of Am and Rare-Earth Elements from Nitric Acid Solutions with Ethyl Bis(diphenylphosphinylmethyl)phosphinate

Extraction of HNO₃ and microamounts of Am, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Y from HNO₃ solutions with solutions of ethyl bis(diphenylphosphinylmethyl)phosphinate in dichloroethane was studied. The stoichiometry of the extractable complexes was determined, and the effective extraction constants of HNO₃ and Am were calculated. With increasing number of phosphoryl groups in the extractant molecule, the extraction of Am(III) and rare-earth elements from HNO₃ solutions increases.     

Extraction of Am(III) and Rare-Earth Elements from Nitric Acid Solutions with Dibutyl Diphenylphosphinylmethylphosphonate

Extraction of HNO₃ and trace amounts of Am, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu nitrates from aqueous HNO₃ with solutions of dibutyl diphenylphosphinylmethylphosphonate in dichloroethane was studied. The stoichiometry of the extractable solvates was determined, and the apparent extraction constants were calculated.     

Extraction Properties of Trioxides of Pentasubstituted Diethylenetriphosphines in Nitric Acid Solutions

Extraction of HNO₃ and microamounts of U(VI), Th(IV), Sc(III), and REEs(III) from HNO₃ solutions with solutions of trioxides of symmetrical dioctyltriphenyldiethylenetriphosphine and pentaphenyl-diethylenetriphosphine in dichloroethane was studied. The stoichiometry of the extractable complexes was determined, and the effective extraction constants of HNO₃ and REEs were calculated. As the number of phosphoryl groups in the extractant molecule increases, the extraction of metal ions from nitric acid solutions is enhanced. Replacement of the octyl radicals at the terminal phosphorus atoms by the phenyl radicals is accom-panied by an increase in extraction of metal ions from solutions with the HNO₃ concentration exceeding 3 M.__________Translated from Radiokhimiya, Vol. 47, No. 1, 2005, pp. 72–76.Original Russian Text Copyright © 2005 by Turanov, Karandashev, Bondarenko.     

Inner-sphere condensation of EtNCO and MeCN through coinsertion into the Re-Cl bond

Reactions of rhenium pentachloride with ethyl isocyanate in dichloroethane and acetonitrile are the first to demonstrate the feasibility of inserting organic isocyanates and nitriles into a rhenium-halogen bond. IR spectroscopy and elemental analysis data show that the addition of one to three ethyl isocyanate molecules in dichloroethane yields ReCl₄[N(Et)C(O) _n ]Cl with n = 1−3, depending on the relationship between the reactants. The reaction in acetonitrile yields a heteromolecular insertion product containing a chain of two isocyanate groups and one nitrile group attached to the same rhenium-chlorine bond: ReCl₄[{N(Et)C(O)}₂N=C(Me)Cl]. When EtNCS is used instead of EtNCO, the reaction is reversible.     

Extraction of Am(III) from Nitric Acid Solutions with Bis(diphenylphosphinylmethyl)phosphinic Acid

Extraction of trace quantities of Am(III) from aqueous HNO₃ solutions with solutions of bis(diphenylphosphinylmethyl)phosphinic acid (I), bis[2-(diphenylphosphinyl)phenoxymethyl]phosphinic acid (II), and bis[2-(diphenylphosphinylmethyl)phenoxymethyl]phosphinic acid (III) in dichloroethane was studied. The stoichiometry of the extractable complexes was determined; the effect of organic diluent on the extraction was considered. The extractive power of the reagents toward Am(III) grows in the order III < II < I. Acid I surpasses in the extractive power a neutral bidentate extractant, tetraphenylmethylenediphosphine dioxide (TPMDPD), by three orders of magnitude. A synergistic effect in extraction of Am with mixtures of TPMDPD and acid I was revealed.     

Extraction of Am(III) and Rare-Earth Elements from Nitric Acid Solutions with (Diphenylphosphinylmethyl)phenylphosphinic Acid

Extraction of microamounts of Am, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu nitrates from aqueous HNO₃ with solutions of (diphenylphosphinylmethyl)phenylphosphinic acid in dichloroethane was studied. The stoichiometry of the extractable complexes was determined. Synergistic enhancement of the extraction of rare-earth elements in the presence of tetraphenylmethylenediphosphine dioxide was revealed.     

Effect of Fe(III) on the extraction of U(VI), Th(IV), and REE(III) from HCl solutions with diphenyl(dibutylcarbamoylmethyl)phosphine oxide

The extraction of U(VI), Th(IV), and REE(III) from HCl solutions with solutions of diphenyl(dibutylcarbamoylmethyl)phosphine oxide in dichloroethane in the presence of Fe(III) was studied. An increase in the Fe concentration in the organic phase leads to a considerable increase in the distribution ratios of U(VI), Th(IV), and REE(III), which is caused by transfer into the organic phase of mixed complexes MCl _m?n (FeCl₄) _n solvated by the extractant molecules. A macroporous styrene-divinylbenzene copolymer impregnated with diphenyl(dibutylcarbamoylmethyl)phosphine oxide can be used for concentrating U(VI), Th(IV), and REE(III) from HCl solutions in the presence of Fe(III).     

Anomalous effects in extraction of lanthanides and actinides with bidentate neutral organophosphorus extractants. Role of proton hydrate solvates

Extraction of europium, lithium, and acids from nitric acid and perchloric acid media with solutions of bidentate neutral organophosphorus compounds (BNOPCs) in polar diluents (dichloroethane, meta-nitrobenzotrifluoride, and trifluoromethyl phenyl sulfone) was studied. It was found that cationic complexes of BNOPCs with proton hydrates or lithium cation are formed in the organic phase. BNOPC hydrate solvates H⁺ · nH₂O · mBNOPC extract europium substantially better than do free BNOPCs. The main differences of BNOPCs from monodentate extractants are anomalous aryl effect (AAE) and perchlorate and synergic (the latter is observed in the presence of chlorinated cobalt dicarbollide) effects, which are connected with specific properties of proton hydrate solvates with BNOPC. The existence of BNOPC cationic complexes found by IR spectroscopy in polar diluents was confirmed by ESI-MS. The effect of preorganization of the extractant molecule and the change from the solvate mechanism of the metal ion extraction to the cation-exchange mechanism are apparently responsible for the high extraction ability of proton hydrate solvates with BNOPCs.     

Extraction of REE(III), U(VI), and Th(IV) from HNO<Subscript>3</Subscript> and HClO<Subscript>4</Subscript> solutions with (α-pyridyl)tetraphenylmethylenediphosphine <Emphasis Type="Italic">N,P,P</Emphasis>'-trioxide

Extraction of microamounts of U(VI), Th(IV), and REE(III) from HNO₃ and HClO₄ solutions with solutions of (α-pyridyl)tetraphenylmethylenediphosphine N,P,P'-trioxide in dichloroethane was studied. The stoichiometry of the extractable complexes was determined, and the influence of the extraction structure and aqueous phase composition on the efficiency and selectivity of the extraction of U(VI), Th(IV), and REE(III) into the organic phase was studied. Introduction of the pyridine N-oxide fragment into the methylene bridge of the tetraphenylmethylenediphosphine dioxide molecule to obtain (α-pyridyl)tetraphenylmethylenediphosphine N,P,P'-trioxide leads to a decrease in its ability to extract U(VI), Th(IV), and REE(III) from nitric acid solutions, whereas the U/REE separation factors increase. The REE(III) extraction efficiency considerably increases in going from nitric acid to perchloric acid solutions.     

Extraction of f Elements and Technetium from HNO3 Solutions with Solutions of Alkyl (N,N-Diethylcarbamoylmethyl)phenylphosphinates

Phosphinic acid derivatives, alkyl (N,N-diethylcarbamoylmethyl)phenylphosphinates (ADPs) were synthesized, studied, and tested as extractants for f elements and technetium at the Mayak Production Association. The distribution factors of these elements D were studied in relation to the ADP and HNO₃ concentrations. The influence exerted by the structure of the alkoxy group at the P atom on DAm and DEu in extraction of Am(III) and Eu(III) (chosen as examples) from nitric acid solutions with solutions of ADPs in dichloroethane was examined. The differences between the distribution factors of Am(III), Pu(IV), U(VI), and Tc(VII) are sufficiently high for complete separation of these elements with a high degree of purification in one step of extraction with ADP solutions. The changes observed in the IR spectrum of the 2-ethylhexyl ADP upon complexation with Pr(III) suggest high complexing power of this reagent toward lanthanide ions. The spectrometric data suggest bidentate coordination of the metal with the chelating groups of the reagent.     

Extraction Properties of Bis(diphenylphosphinylethyl)phosphinic Acid in Nitric Acid Solutions

Extraction of microamounts of U(VI), Th(IV), Sc(III), and Ln(III) from HNO₃ solutions with solutions of bis(diphenylphosphinylethyl)phosphinic acid in dichloroethane was studied. The stoichiometry of the extractable complexes was determined, and the effect of the inorganic anion and organic diluent on the extraction of rare-earth elements was examined. An increase in the number of phosphoryl groups in the extractant molecule and replacement of ethylene bridges between the phosphorus atoms by methylene bridges enhance the extraction of metal ions from nitric acid solutions.__________Translated from Radiokhimiya, Vol. 47, No. 3, 2005, pp. 252–256.Original Russian Text Copyright © 2005 by Turanov, Karandashev, Ragulin.     

Complexation of polyethylene glycol with Sr<Superscript>2+</Superscript> and Ba<Superscript>2+</Superscript> cations in extracts containing chlorinated cobalt dicarbollide

The composition and structure of complexes that are formed in the system consisting of chlorinated cobalt dicarbollide (CCD), polyethylene glycol (PEG), and Sr²⁺ or Ba²⁺ in a polar diluent, dichloroethane or phenyl trifluoromethyl sulfone, were studied by IR and NMR spectroscopy. In extraction of Sr²⁺ and Ba²⁺ with solutions of [H₅O ₂ ⁺ PEG]CCD^–, the organic phase contains the ionic associates [M²⁺PEG]CCD ₂ ^– . The Sr²⁺ and Ba²⁺ complexes have similar composition and structure: The oxygen atoms of two OH groups and six COC groups of a PEG molecule fill the first coordination sphere of the metal ions. Also, no more than two water molecules can be coordinated in the second sphere, forming hydrogen bonds with the hydrogen atoms of two OH groups of PEG. The coordination of the OH groups of PEG with the Sr²⁺ and Ba²⁺ ions is preferable over the coordination of the COC groups, as follows from the fact that the extraction of Sr²⁺ and Ba²⁺ with CCD-PEG mixtures gets worse on replacement of the OH groups of PEG by other substituents. A considerable increase in the efficiency of Sr²⁺ and Ba²⁺ extraction with H-CCD solutions in the presence of PEG is due to the fact that all the H₂O molecules in the first coordination spheres of the M²⁺ ions are replaced by the COC and OH groups of PEG with the formation of a hydrophobic complex [M²⁺PEG](H₂O)₂.Translated from Radiokhimiya, Vol. 46, No. 6, 2004, pp. 540–545.Original Russian Text Copyright © 2004 by Stoyanov, Smirnov, Babain, Antonov, Peterman, Herbst, Todd, Luther.     

Synthesis and IR spectroscopic characterization of fluorinated graphite intercalation compounds with chlorinated derivatives of methane and ethane

We have synthesized (C₂F _x Br_0.01 · yG) _n intercalation compounds with (C₂F _x Br_0.01) _n as a host and G (dichloromethane, chloroform, carbon tetrachloride, and dichloroethane) as a guest (x and y are stoichiometric coefficients). The behavior of the functional groups in the guest and host subsystems has been studied by IR spectroscopy. We have examined the influence of the degree of fluorination of the polymer host (0.5 < x < 1.0) and the nature of the guest on the vibrational frequencies of the C-F and C-Cl bonds.     

Extraction of Actinides from HNO3 Solutions with Solutions of Dialkyl Methylphosphonates

Extraction of actinides with dialkyl methylphosphonates was studied with the aim to find a compromise between the use of highly effective but expensive chemicals, on the one hand, and weakly effective but cheap and readily available chemicals, on the other hand, and also to find possible ways of utilization of methylphosphonic dichloride, which is the starting substance in syntheses not only of dialkyl methylphosphonates, but also of chemical weapons. In systems with 3 M HNO₃ as the aqueous phase and a solution of tributyl phosphate (TBP), diisoamyl methylphosphonate (DIAMP), or bidentate diphenyl(carbamoylmethyl)phosphine oxide (Ph₂Bu₂) in dichloroethane as organic phase, at equal concentrations of the organophosphorus compounds, the distribution coefficients of Am(III) increase in the order TBP <; DIAMP < Ph₂Bu₂ in a proportion of 1 : 50 : 5 × 10⁴. Mixtures of dialkyl methylphosphonates and acidic phosphonates show a synergistic effect, which, however, can be utilized only at [HNO₃] > 0.1 M and [HIAMP] < 1.5 M (HIAMP is isoamyl hydrogen methylphosphonate).     

Extraction of Mo from solutions in HNO<Subscript>3</Subscript> and other mineral acids with solutions of dibutyl hydrogen phosphate in a diluent

Extraction of Mo from HNO₃ solutions with solutions of HDBP in xylene and CCl₄ in a wide range of Mo concentrations was studied. The Mo distribution ratios are considerably higher with CCl₄ diluent compared to xylene, but the extractant capacity in both cases is the same and corresponds to the ratio HDBP: Mo = 2. The active species in the Mo extraction is the HDBP dimer. In the first step, an acidic molybdenyl salt with HDBP of the composition MoO₂(DBP)₂(HDBP)₂, exhibiting certain secondary extraction properties toward rare-earth elements, is formed in all the cases. The dependence of the Mo extraction on the aqueous solution acidity passes through a minimum at 3–4 M HNO₃. The subsequent increase in the Mo distribution ratios is associated with the simultaneous extraction of HNO₃ (or nitrate ion) whose concentration in the extract is considerably lower than the Mo concentration. With an increase in the loading of the extract with molybdenum, the acidic molybdenum salt of HDBP undergoes restructurization, probably associated with additional coordination of H₂MoO₄ to it. The dependence of the Mo distribution ratio on the acid concentration in the extraction from sulfuric acid solutions passes through a minimum at 3–4 M H₂SO₄, which correlates with the first step of the acid dissociation, and in the extraction from HClO₄ the dependence passes through a minimum and a maximum. In the extraction from hydrochloric acid solutions, the Mo extractability decreases with an increase in the acid concentration, owing to complexation in the aqueous phase. The nature of processes occurring at various loadings of the extract with molybdenum are discussed.     

Extraction of lanthanide nitrates with trioctylmethylammonium di(2,4,4-trimethylpentyl)phosphinate

A binary extractant based on trioctylmethylammonium di(2,4,4-trimethylpentyl)phosphinate R₄NA was prepared. The extraction of lanthanide (Gd-Lu) nitrates from aqueous solutions with 0.6 M toluene solutions of R₄NA and trioctylmethylammonium nitrate was studied. The extraction isotherms of lanthanide nitrates with these extractants were obtained and physicochemical and mathematical models of extraction of lanthanides were developed. The extraction isotherms with the binary extractant were analyzed assuming that the Ln(III) extractable complexes LnA₃, (R₄N)₂[Ln(NO₃)₅], (R₄N)₃[Ln(NO₃)₆], (R₄N)₂[Ln(NO₃)₃A₂], and (R₄N)[Ln(NO₃)₃A] [A is di(2,4,4-trimethylpentyl)phosphinate anion] are formed in the organic phase. The extraction constants were calculated.     

Extraction of uranyl nitrate with a binary extractant based on trialkylbenzylammonium and higher isomeric α,α′-branched carboxylic acids

A binary extractant based on trialkylbenzylammonium and higher isomeric α,α′-branched carboxylic acids (R₄NA) was synthesized. The extraction of uranyl nitrate with 0.52 M solutions of R₄NA and R₄NNO₃ in toluene was studied. The extraction isotherms were constructed. The physicochemical and mathematical models of the extraction of uranyl nitrate were developed. The following extractable species were shown to be formed in the organic phase: (R₄N)₂[UO₂(NO₃)₄], R₄N[UO₂A(NO₃)₂], and (R₄N)₂[UO₂A₂(NO₃)₂] The extraction constants were calculated. The organic phase was examined by IR spectroscopy.