Solvent Extraction of Alkaline Earths with 1-Phenyl -3-Methyl 4 Stearoylpyrazol - 5 - One and Topo

Abstract

The synergic extraction of Ca, Sr, and Ba ions from aqueous solutions into cyclohexane or benzene containing 1- pheny 1 - 3 - methyl - 4 - stearoylpyrazol - 5 - one (HPMSP) and TOPO has been studied. Quantitative extraction (log D>2) was attained at pH>5.4 for Ca, pH>6.5 for Sr, and pH>7.3 for Ba when cyclohexane containing 0.05 M HPMSP and 0.01 M TOPO was used, and the corresoponding values for benzene were 6.5, 7.8, and 8.4. Extracted species were M(PMSP)₂(TOPO)₃ (M=Ca, Sr, Ba) for cyclohexane and Ca(PMSP)₂(TOPO)₃ and Sr (or Ba) (PMSP)₂(TOPO)₂ for benzene.     

Synergistic extraction of uranium(VI) and thorium(IV) with mixtures of Cyanex272 and other organophosphorus ligands

The extraction of thorium(IV) and uranium(VI) from nitric acid solutions has been studied using mixtures of bis(2,4,4-trimethylpentyl)phosphinic acid (Cyanex272 or HA), and synergistic extractants (S) such as tri-butylphosphate (TBP), tri-octylphosphine oxide (TOPO) or bis(2,4,4-trimethylpentyl)thiophosphinic acid (Cyanex301). The results showed that these metallic ions are extracted into kerosene as Th(OH)₂(NO₃)A·HA and UO₂(NO₃)A·HA with Cyanex272 alone. In the presence of neutral organophosphorus ligands TBP and TOPO, they are found to be extracted as Th(OH)₂(NO₃)A·HA·S and UO₂(NO₃)A·HA·S. On the other hand, Th(IV), U(VI) are extracted as Th(OH)₂(NO₃)A·HA·2S and UO₂(NO₃)A·HA·S in the presence of Cyanex301. The addition of neutral extractants such as TOPO and TBP to the extraction system enhanced the extraction efficiency of both elements while Cyanex301 as an acidic extractant has improved the selectivity between uranium and thorium. The effect of TOPO on the extraction was higher than other extractants. The equilibrium constants of above species have been estimated by non-linear regression method. The extraction amounts were determined and the results were compared with those of TBP. Also, it was found that the binding to the neutral ligands by the thorium–Cyanex272 complexes follows the neutral ligand basicity sequence.     

The extraction of uranium(VI), americium and europium by LIX 64 and by a mixture of LIX 64 and tri-n-octylphosphine oxide

The extraction of U(VI), Eu and Am by the aromatic main component (HA) of LIX 64N dissolved in toluene was studied at pH 3–9. The values of pH_1/2 for the extraction with 0.146 M HA are 4.0, 5.5 and 5.2, and the pH's of maximum extraction are 6.0, 6.8, and 7.0 for U(VI), Eu and Am, respectively. The stoichiometry of the extracted chelates determined by the slope analysis is UO₂A₂ and MA_3–nY_n (n=1,2) for Eu and Am, the ligand Y being probably the nitrate anion. The addition of tri-n-octylphosphine oxide (TOPO) enhances the extraction of U(VI) and especially of Eu at pH<6. An Eu chelate species solvated by 2 TOPO molecules is extracted at pH 4 by the mixture of HA+TOPO, whereas the species extracted at pH 6.5 is not solvated by TOPO.     

Synergistic extraction of copper(II) from sulfate medium with capric acid and tri-n-octylphosphine oxide in chloroform

The synergistic solvent extraction of copper(II) from 0.33?mol?dm^?3 Na₂SO₄ aqueous solutions with capric acid (HL) in the absence and presence of tri-n-octylphosphine oxide (TOPO) in chloroform at 25°C has been studied. The extracted species when capric acid was used alone is CuL₂(HL)₂. In the presence of TOPO, the extracted complex is CuL₂(HL)₂(TOPO). The TOPO–HL interaction strongly influences the synergistic extraction efficiency. The extraction constants were calculated.     

Extraction of thorium(IV) by a mixture of 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone and tri-n-octyl phosphine oxide

The extraction behavior of Th(IV) from dilute nitric as well as perchloric acid medium using 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone (PMBP) and its mixture with tri-n-octyl phosphine oxide (TOPO) was investigated. The species of the type Th(X)(PMBP)₃·(HPMBP) and Th(X)(PMBP)₃·(TOPO) were extracted for the binary and ternary extraction systems, respectively, where X=NO₃− or ClO₄−. The presence of 1.25·10⁻⁵M Th carrier in the aqueous phase resulted in the extracted species of the type of Th(PMBP)₄ and Th(PMBP)₄·(TOPO), respectively. The extraction constant (logk _ex ) for the binary species Th(PMBP)₄ was found to be 6.89±0.01 while the overall extraction constant (logK) for the ternary species Th(PMBP)₄·(TOPO) was calculated to be 13.17±0.06.     

Studies on mixed ligand complexes of samarium(III), europium(III) and dysprosium(III) with 1-nitroso-2-naphthol and trioctylphosphine oxide

The extraction behavior of Sm(III), Eu(III) and Dy(III) with 1-nitroso-2-naphthol (HA) and trioctylphosphine oxide (TOPO) in methyl isobutyl ketone (MIBK) from aqueous NaClO₄ solutions in the pH range 4–9 at 0.1M ionic strength has been studied. The equilibrium concentrations of Sm and Dy were measured using their short-lived neutron activation products,¹⁵⁵Sm and^165mDy, respectively. In the case of Eu, the concentrations were assayed through the^152,154Eu radiotracer. The distribution ratios of these elements were determined as a function of pH, 1-nitroso-2-naphthol and TOPO concentrations. The extractions of Sm, Eu and Dy were found to be quantitative with MIBK solutions in the pH range 5.9–7.5, 5.6–7.5 and 5.8–7.5, respectively. Quantitative extraction of Eu was also obtained between pH 5.8 and 8.8 with chloroform solutions. The results show that these lanthanides (Ln) are extracted as LnA₃ chelates with 1-nitroso-2-naphthol alone, and in the presence of TOPO as LnA₃(TOPO) and LnA₃(TOPO)₂ adducts. The extraction constants and the adduct formation constants of these complexes have been calculated.     

Studies on extraction of copper(II) with 1-phenyl-3-methyl-4-acyl-5-pyrazolone

The extraction of Cu(II) with 1-phenyl-3-methyl-4-acyl-5-pyrazolone (HA), in different organic solvents has been studied. The extraction mechanism of Cu(II) and the composition of the extracted species has been determined. Cu(II) was extracted as CuA₂, or in the presence of TOPO, as CuA₂TOPO. The extraction constants do not change regularly with increasing the length of acyl chain in the 1-phenyl-3-methyl-4-acyl-5-pyrazolone derivatives. The effect of the temperature on the extraction of Cu(II) has also been investigated.     

Synergistic extraction of U(VI) and Th(IV) from nitric acid with 4-benzoyl-2,4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-thione (HBMPPT) and tri-n-octylphosphine oxide (TOPO) in toluene

The extractant HBMPPT (4-benzoyl-2,4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-thione) was synthesized from HBMPP. Its m.p. was 106–108°C. The synergistic extraction of U(VI) and Th(IV) from nitric acid solution by HBMPPT and TOPO in toluene was studied. The extraction ability of HBMPPT was not so high as that of its parent (HBMPP), but when a little tri-n-octylphosphine oxide (TOPO) was added the ability to extract U(VI) and Th(IV) was seriously improved. The synergistic extracted complexes may be presented as UO₂NO₃·BMPPT·TOPO and UO₂(BMPPT)₂·TOPO for U(VI), and Th(NO₃)₃·BMPPT·TOPO and Th(NO₃)₂(BMPPT)₂·TOPO for Th(IV) respectively.     

Solvent extraction of americium by imidodiphosphates and diimidotriphosphates

Solvent extraction was described for determining of the americium content in the liquid samples. Arylesters of imidodiphosphoric, imidothiodiphosphoric, imidodithiodiphosphoric acids and tetraphenylimidodithiodiphosphine are used as representatives of bidentate organophosphoric extractants. From the group of tridentate agents, pentaphenyldiimidotriphosphate, was used. The extraction properties of tetraphenyl imidodiphosphates and their sulphur analogues for trivalent americium in 0.1 mol L⁻¹ HNO₃ into toluene also in the presence of tri-n-octylphosphine oxide (TOPO) were investigated. The dependences of equilibrium ratios of the americium on analytical or equilibrium concentration of chelating agents, pH, initial concentration of nitric acid and initial concentration of TOPO were studied. The structures of the complexes in the organic phase were determined and the values of extraction constants were calculated. The extracted species were AmA₃, AmA₃ (HA), the addition of TOPO induced synergistic extraction of AmA₃ TOPO. The utilization of sulphur analogues was marginal.     

Adduct formation properties of mono- and bidentate phosphine oxide compounds in the liquid—liquid extraction of some divalent metals with 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone

The bidentate phosphine oxide compounds bis(diphenylphosphinyl)methane (BDPPM) and bis(diphenylphosphinyl)ethane (BDPPE) were synthesized and the liquid—liquid extraction equilibria of some divalent metal ions such as Co(II), Ni(II), Zn(II) and Cd(II) with 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone (HPMBP) and the neutral phosphine oxide compounds were investigated. BDPPM was found to be much more powerful than BDPPE and the monodentate neutral ligand trioctylphosphine oxide (TOPO). The composition of the extracted species were determined by a graphical method to be M(PMBP)₂(TOPO)_s (s = 2 for Co, Ni, Cd and s = 1 for Zn), M(PMBP)₂(BDPPM) and M(PMBP)₂(BDPPE). The adduct formation constants between the acylpyrazolone chelates and the neutral ligands were determined and are discussed in terms of the molecular structure.     

Substoichiometric liquid-liquid extraction and determination of vanadium based on the synergic effect of thenolytrifluoroacetone and trioctylphosphine oxide

Vanadium(IV) is extracted synergically with thenoyltrifluoroacetone (HTTA) and trioctylphosphine oxide (TOPO) in cyclohexane as the mixed ligand complex, VO(TTA)₂TOPO. The synergic extraction constant is 10^5.06. The system can be used for the substoichiometric extraction of vanadium(IV); vanadium(IV) is extracted at pH 4.0–5.0 with a substoichiometric amount of HTTA in the presence of an excess of TOPO. The substoichiometric process combined with isotope dilution was successfully applied to the determination of vanadium(IV) in NBS-1633 coal fly ash; the value found was 222.5 ± 3.5 μg g^?1. The method is shown to be accurate and precise.     

Synergism in the solvent extraction of samarium by thenoyltrifluoroacetone and triphenyl or trioctyl phosphine oxide mixture

Synergistic extraction of samarium with TTA(HA) and TPPO or TOPO (B) mixtures were investigated. The extracted complex was proved to have the general formula SmA₃ · 2B. A graphical determination for the formation constants of these complexes gave the values 3.9 × 10¹³ and 8.2 × 10¹⁰ for SmA₃ · 2TOPO and SmA₃ · 2TPPO in benzene, respectively.     

Behavior of nitrite forms of nitrosylruthenium on extraction and back extraction of heterometalic Ru/Zn complexes with trioctylphosphine oxide

The state of ruthenium in conjugated phases upon extraction of trans-[Ru(¹⁵NO)(¹⁵NO₂)₄(OH)]^2? complex with tri-n-octylphosphine oxide (TOPO) in the presence of Zn²⁺ and subsequent back extraction with H¹⁵NO₃ and NH₃(concd.) solutions was studied by ¹⁵N NMR. Binuclear complexes [Ru(NO)(NO₂)_5?n (μ-NO₂) _n?1(μ-OH)Zn(TOPO) _n ] and [Ru(NO)(NO₂)_4?n (ONO)(μ-NO₂) _n?1(μ-OH)Zn(TOPO) _n ], where n = 2, 3, are predominant forms in extract. Kinetic restrictions for ruthenium extraction with TOPO solution in hexane and its back extraction with aqueous solutions of nitric acid and ammonia are eliminated in the absence of direct coordination of extractant to ruthenium. fac-Dinitronitrosyl forms [Ru(NO)(H₂O)₃(NO₂)₂]⁺, [Ru(NO)(H₂O)₂(NO₂)₂(NO₃)]⁰ (3 and 6 M HNO₃) and [Ru(NO)(H₂O)(NO₂)₂(NO₃)₂]^? (6 M HNO₃) prevail in nitric acid back extracts. Equilibrium constant at ambient temperature (0.05 ± 0.01) was assessed for the coordination of second nitrate ion to nitrosylruthenium dinitronitrato complex. Complex species [Ru(NO)(NO₂)₄(OH)]^2? and [Ru(NO)(NO₂)₃(ONO)(OH)]^2? prevail in ammonia back extract.     

Solvent extraction of Np(IV) and Pu(IV) with mixtures of TOPO and HTTA

Solutions of HTTA are known to extract tetravalent actinides as M(TTA)₄ species. When TOPO is added to HTTA solutions, the extracting of Np(IV) and Pu(IV) from aqueous perchloric acid was enhanced enormously. The species responsible for the enhanced extraction were identified from the extraction data by the slope ratio method and JOB's method. It was found that the predominant species responsible for enhancement in the extraction, when [HTTA]≫[TOPO], was M(TTA)₄. TOPO for both Np(IV) and Pu(IV). Furthermore, it was established that depending on the relative concentrations of HTTA and TOPO, a number of species with the composition M(TTA)_a(ClO₄)_4-a·b TOPO, with a ranging from 1 to 4 and b having values of 1 or 2, are involved in the extraction. Several equilibrium constant values are given. Fuel Reprocessing Division.     

Formation of coordination compounds in gadolinium-loaded liquid organic scintillators (GdLS): Use of mixed-ligand gadolinium complexes in GdLS preparation

The formation of coordination compounds between gadolinium 2-methylvalerate (Gd(2MVA)₃) and trioctylphosphine oxide (TOPO) in a gadolinium-loaded liquid scintillator (GdLS) solution was studied by MALDI-TOF MS. The most abundant gadolinium-containing compound in the GdLS solution in the presence of TOPO is the monomer complex Gd(2MVA)₃ · (TOPO)₂. In the absence of TOPO, the solution contains only Gd _n (2MVA)_3n (n = 2–5) association species. Therefore, TOPO prevents carboxylate polymerization in the solution and can be used as a stabilizer of the gadolinium compounds in GdLS. The existence of the Gd(2MVA)₃ · TOPO complex is confirmed by IR spectroscopy. The possibility of coordination between Gd(2MVA)₃ and 2,5-diphenyloxazole (PPO), the most common scintillation admixture, has been investigated. No complexes between Gd(2MVA)₃ and PPO have been detected by MALDI-TOF MS in the scintillator solution. IR spectroscopic data also do not provide any unambiguous indication of coordination between Gd(2MVA)₃ and PPO.     

Steric effect of ortho-substituents of 1-phenyl-3-methyl-4-aroyl-5-pyrazolones on the synergic extraction of lutetium with trioctylphosphine oxide

The substituent effect of ortho-substituted 4-aroyl derivatives of 1-phenyl-3-methyl-5-pyrazolones (HA) on the adduct formation reaction between their lutetium chelates and a neutral ligand, trioctylphosphine oxide (TOPO, L), in benzene was studied using a liquid-liquid extraction system. The lutetium 4-aroyl-5-pyrazolonates react with TOPO to form LuA₃L and LuA₃L₂ types of adducts. An obvious steric hindrance of the terminal group on the adduct formation reaction was observed. Linear relationships between the acid dissociation constant of the ortho-substituted 4-aroyl-5-pyrazolone derivatives and those of the corresponding benzoic acids, between the extraction constants of lutetium and the acid dissociation constants of pyrazolones and between the adduct formation constants of TOPO and the acid dissociation constants of pyrazolones could be obtained.     

Some studies on synergic extraction of mixed ligand species of uranium(VI)

The extraction of U(VI) by mixtures of HTTA and TBP from aqueous thiocyanate medium has been studied. From the data obtained it was observed that the predominant uranium species extracted, causing synergic enhancement in the extraction of U(VI), is UO₂(SCN)TTA · 2TBP when benzene and cyclohexane are used as diluents, and that at a very low concentration of TBP the contribution of additional species, viz. UO₂(TTA)₂ · TBP becomes significant. With chloroform as diluent, however, both of these species are contributing to the synergic enhancement. The extraction of a quaternary uranium species, UO₂(SCN)TTA · 2TBP, involving the participation of the aqueous anion is thus established. Equilibrium constants for the various extraction equilibria involved are calculated.     

Extraction of uranium (VI) from sulfuric acid solution with TOPO

The extraction of uranium(VI) from sulfuric acid medium with tri-octylphosphine oxide (TOPO) in n-heptane was studied. Accompanied with the increase in the concentration of H₂SO₄, the distribution coefficient of uranium(VI) increased in the region of dilute sulfuric acid. When the concentration of H₂SO₄ surpassed 3.5 mol·dm⁻³, the distribution coefficient of uranium(VI) was at maximum. This result was due to the competition extraction between uranium(VI) and H₂SO₄. From the data, the composition of extracted species and the equilibrium constant of extraction reaction have been evaluated, which were (TOPOH)₂UO₂(SO₄)₂ (TOPO) and 10^7.6±0.15, respectively.     

Synergic solvent extraction studies of gadolinium using a combination of the di(2-ethylhexyl)phosphoric acid and three adductants into kerosine/chloroform

The equilibrium extraction behaviour of Gd(III) using a chloroform/kerosine solution containing di(2-ethylhexyl)phosphoric acid (HDEHP), either alone or combined with one of three adductants, 1,10-phenanthroline monohydrate (phen), alpha,alpha'-dipyridyl(2,2'-bipyridine) (bipy) or trioctylphosphine oxide (TOPO) is described. The enhancement of the extraction by addition of such neutral adductants is explained in terms of adduct formation of the metal chelate in the organic phase. Among the three synergistic mixtures, 1,10-phenanthroline is the most promising for the extraction of the last member of light lanthanoids, gadolinium. Gadolinium ions are found to be extracted in the absence of phen, bipy or TOPO; the species was M(HA(2))(3) but M(HA(2))(3))(phen)(2) was found when phen was added and M(HA(2))(3)(bipy), M(HA(2))(3)(bipy)(2) was found when bipy was added and M(HA(2))(3)(TOPO) was found when TOPO was added. The compositions of the extracted species are obtained from the slope analysis method. pH (1 2 ) values were also obtained. The stoichiometry, extraction constants and stability constants of these systems were determined. Synergistic extraction can be carried out at lower pH.