New Ionic Liquid Based on the CMPO Pattern for the Sequential Extraction of U(VI), Am(III) and Eu(III)

Extraction of U(VI), Eu(III) and Am(III) has been performed from acidic aqueous solutions (HNO₃, HClO₄) into the ionic liquid [C₄mim][Tf₂N] in which a new extracting task-specific ionic liquid, based on the CMPO unit {namely 1-[3-[2-(octylphenylphosphoryl)acetamido]propyl]-3-methyl-1H-imidazol-3-ium bis(trifluoromethane)sulfonamide, hereafter noted OctPh-CMPO-IL}, was dissolved at low concentration (0.01 mol·L^?1). EXAFS and UV–Vis spectroscopy measurements were performed to characterize the extracted species. The extraction of U(VI) is more efficient than the extraction of trivalent Am and Eu using this TSIL, for both acids and their concentration range. We obtained evidence that the metal ions are extracted as a solvate (UO₂(OctPh-CMPO-IL)₃) by a cation exchange mechanism. Nitrate or perchlorate ions do not play a direct role in the extraction by being part of the extracted complexes, but the replacement of nitric acid for perchloric acid entails a drop in the selectivity between U and Eu. However, our TSIL allows a sequential separation of U(VI) and Eu/Am(III) using the same HNO₃ concentration and same nature of the organic phase, just by changing the ligand concentration.     

Solvent extraction of alkaline earth metals,and lithium with 1-phenyl-3-methyl-4-acylpyrazol-5-ones and trioctylphosphine oxide

The synergic extraction of magnesium, calcium, strongium, barium and lithium into cyclohexane or benzene containing 1-phenyl-3-methyl-4-acyl-pyrazol-5-one (HA) and tri-n-octylphosphine oxide (TOPO) was investigated as a function of pH, HA and TOPO concentration. The extracted species when the 4-benzoyl compound was used, were MA₂(TOPO)₂ (M = Mg, Ca, Sr), BaA₂(TOPO)₃ and LiA(TOPO)₂. When the 4-trifluoro-acetyl derivatives was used, the extracted species were the same except for SrA₂(TOPO)₃. Extraction constants for the synergic extractions were calculated.     

Mixed ligand complexes of europium,dialkylphosphoric acids and perchlorate anion

The solvent extraction of europium(III) with di-n-butylphosphoric {HDBP} and di-(2-ethylhexyl)phosphoric {HDEHP} acids in 3-methyl-1-butanol from 0.1 and 1.0M perchlorate medium {Na(H)ClO₄} was studied at pH 1–3. It was found that the composition of the species extracted into the organic phase depended on the concentration of perchlorate anion. In 0.1M Na(H)ClO₄ solutions, simple chelates Eu(DBP)₃ or Eu(DEHP)₃ are extracted while mixed ligand complexes Eu(DBP)₂ClO₄ or Eu(DEHP)₂ClO₄ are also extracted from 1.0M Na(H)ClO₄ solutions. Compared to the extractions from perchlorate solutions, no such change in the extraction mechanism has been observed in chloride solutions containing up to 1.0M Cl^–. The extraction of europium(III) with these extractants into toluene from 0.1M perchlorate or chloride media was studied as well. The extraction species found were identical with those reported in the literature, i.e. {Eu[H(DBP)₂]₃, Eu[H(DEHP)₂]₃}. The extraction equilibrium constants were calculated for all complexes.     

Indirect Determination of Lidocaine by Atomic Absorption Spectrophotometry

Abstract

A new procedure for determining lidocaine chlorhydrate is described. The method consists of extracting an ion pair composed of Lidocaine and the inorganic complex Co(SCN)₄ ^2- into an organic solvent (1, 2 dichloroethane), then measure the Co in the organic phase by A.A.S. at 240.7 mm. Optimal experimental conditions concerning pH, Co(SCN)₄ ^?2 concentration, shaking time, phase ratio, number of extractions and linear range for calibration are studied. The method has a standard deviation of 10^?2. Two pharmaceutical preparations containing lidocaine, have been analyzed with very good results.     

Solvent extraction of uranium(VI) by p-tert-butylcalix[n]-arene acetate

The solvent extraction of U(VI) by p-tert-butylcalix[n]-arene acetate (H _n L) (n=4, 6, 8) has been studied. The effects of acidity in aqueous phase and concentration of extractant in organic phase on the distribution ratio were examined. It has been found that the distribution ratio is proportional to [H⁺]⁻² and [H _n L]_(O) and the extracted complex species is UO₂H _n ⁻²L. The equilibrium constants of the extraction reactions have been determined. The reaction mechanism is discussed.     

Solvent extraction of cobalt(II), zinc(II) and europium(III) with 4-thiobenzoyl-2,4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-one (SBMPP)

Solvent extraction of⁶⁵zinc,⁶⁰cobalt and^152+154europium from aqueous buffers into benzene containing 4-thiobenzoyl-2,4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-one (SBMPP) has been investigated in detail (μ=0.1, T=26±1°C). The species extracted and the values of log K_ex, where K_ex refers to the extraction equilibrium, are ZnL₂ (−2.68) CoL₂(−3.08) and EuL₃(−7.08), where L is the anion of the ligand. The sulfur analog appears to be more effective than the parent ligand 4-benzoyl-2,4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-one in the extraction of zinc(II) and cobalt(II), whereas the reverse is true with europium(III).     

The Comprehensive Nuclear Test-Ban-Treaty and the radiological risk to on-site inspection teams

The solvent extraction behavior of thorium traces from the hydrochloric acid media with 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone (PMBP) is described using ²³⁴Th as a tracer. The influence of certain variables such as extractant concentration, acidity, equilibrium time as well as UO₂ ²⁺ ions on the extraction of thorium has been investigated systematically. The back-extraction behavior of thorium from the organic phase has also been tested. The results reveal that the percent extraction of ²³⁴Th decreases with increasing hydrochloric acid concentration and thorium is easily back-extracted with an 4-6 mol/l aqueous HCl solution. At the same time, the effect of thorium extraction with PMBP was tested employing radioisotopes as multi-tracers in the irradiation of natural uranium with 14-15 MeV neutrons. The results show that thorium can be completely separated from a large amount of uranium and most of the other main reaction products.     

Extraction of sulfuric acid with TOPO

A study on solvent extraction of sulfuric acid by tri-octylphosphine oxide (TOPO) in n-heptane has been made. Extraction coefficients of H₂SO₄ as a function of H₂SO₄ concentration in aqueous phase, and extractant concentrations in organic phase have been studied. The composition of extracted species, equilibrium constants of extraction reaction have been evaluated. These results are important for interpreting extraction equilibrium data of uranium(VI) or other metal ions with TOPO in sulfuric acid media.     

Extraction study of uranium(VI) and thorium(IV) salicylates with triphenylarsine oxide

Triphenylarsine oxide is proposed as an extractant for the solvent extraction of uranium and thorium salicylates. The optimum extraction conditions are established by studying the various parameters such as pH, sodium salicylate concentration, triphenylarsine oxide concentration, diluents and shaking time. The probable extracted species as ascertained by logD-logC plots are UO₂(Hsal)₂·2TPAsO and Th(Hsal)₄·2TPAsO. The method is simple, fast, precise and permits the determination of uranium and thorium in monazite sand samples.     

Solvent Extraction Behavior of Astatine and Radioiodine at Tracer Concentrations

The solvent extraction behavior of radioioine and astatine has been investigated under various conditions in order to compare the extraction behavior of astatine with radioiodine at tracer concentration. In this study, basic tracer solutions of astatine and radioiodine were extracted into the CS₂ solution under various conditions. Astatine existed as a pure species in the tracer solution and formed cationic compound in the acidic solution which was also extracted into the organic solvent instantaneously. On the other hand, radioiodine existed as a complex in the tracer solution and was partly extracted into the organic solvent at tracer concentration. The observed different extraction behavior of astatine and radioiodine were consistently explained by the respective proposed extraction reaction schemes.     

Extraction equilibria for the 4-(2-Pyridylazo)-Resorcinol-Nickel(II)-Quaternary-Ammonium salt system

The extraction equilibria of nickel(II)-PAR complexes with tetradecyldimethylbenzylammonium chloride(Q⁺Cl^?) are investigated. Two kinds of nickel complex are extracted by chloroform: Ni(HR)₂,nQ⁺Cl^?₍₀₎(?⁵⁰⁰ = 3.73·10⁴l mol^?1cm^?1) at about pH 5 and 2Q⁺ NiR^2-_2(o)(?⁵⁰⁰ = 8.08·10⁴ l mol^?1 cm^?1) at above pH 8.5. The extraction constant for 2Q⁺ NiR^2-_2(o) was evaluated as [2Q⁺ NiR^2-₂]₀/[NiR^2-₂] [Q⁺]² = 10^11.16 at μ = 0.1 (Na₂SO₄. Synergic extraction studies of the Ni(HR)₂ species under slightly acidic conditions show that the species is Ni(HR)₂(H₂O)₂in auqeous solution and is extracted into chloroform as the adduct Ni(HR)₂(TBP)₂ (?⁵³⁵ = 3.57·10⁴ l mol^?1 cm^?1. Based on the extraction behavior of these complexes, the structures of the Ni²⁺—PAR complexes are discussed.     

Solvent polarity indicators: Extraction of some coumarin indicator dyes

Study of the extraction of ten different coumarins (unsubstituted, 6-methyl-, 7-methyl-, 4-hydroxy-, 7-hydroxy-, 7-hydroxy-4-methyl-, 7-methoxy-, 7-amino-4-methyl-, 7-diethyl-amino-4-methyl-, and 3-carboxy-) with nine organic solvents shows that the percentage extraction is generally high. Cyclohexanone and heptane were found to be, respectively, the most and least effective extracting solvents for the compounds under study. The results are discussed in terms of the effect of different solvent polarity parameters on the extraction process.     

Solvent Extraction of Pb(II) with AGDOMD

Abstract

The distribution of Pb(II) between an aqueous phase and a toluene phase containing dehydrated fatty acids found in distilled castor oil (AGDOMD) has been studied. Using the slope technique the conditional equilibrium constant of extraction was determined (kext = 1.02 × 10^?7) and the main species present in the organic phase was identified as (PbNO₃R. 2HR)_(o), where HR represents the fatty acid used.     

Extraction of Ni(II) from nitrate media by Di-n-octylphosphinic acid dissolved in toluene

The extraction of Ni(II) from nitrate media of ionic strength 1.0 mol dm⁻³ by di-n-octylphosphinic acid (HR) in toluene solution has been studied over a range of pH and reagent concentrations. The data have been analysed both graphically and numerically to determine the stoichiometry of the extracted complexes and their extraction constants. Evidence was found for the formation of both NiR₂(HR)₄ (log K₂₄ = −9.14±0.06) and NiR₂(HR)₂ (logK₂₂ = −7.35±0.10), the former being the predominant species although the latter is important at low reagent concentrations and high pH values.     

Extraction of technetium by DB18C6 and 18C6 into nitrobenzene and acetylacetone from an aqueous phase containing NaBH4

The extraction of technetium by DB18C6 and 18C6 into nitrobenzene and different solvents from aqueous phase containing NaBH₄ was investigated. The experimental data indicate that the main extracted species have the formulas TcO/OH/₂.CE or 2TcO/OH/₂.3CE, where CE refers to the crown ethers. The effects of crown ether concentration, pH and organic solvent on the distribution ratio are discussed. The extent of extraction from different solvents decreases in the order nitrobenzene >acetylacetone>1-butanol>toluene> benzene.     

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.     

Extraction of rare-earth,yttrium, and scandium perchlorates by podands bearing diphenylphosphorylacetamide terminal groups

Partition of trace amounts of metal (La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Y, and Sc) perchlorates was studied between aqueous HClO₄ solutions and dichloroethane solutions of phosphorus podands bearing two Ph₂P(O)CH₂C(O)NH-terminal groups linked via di-and triethylene glycol spacers. The stoichiometry of extracted complexes was determined. The efficiency of metal ion recovery to the organic phase was studied as a function of aqueous HClO₄ concentration and nature of the organic solvent. The compounds synthesized have higher metal extraction capacities in HClO₄ solutions than (dibutylcarbamoyl)diphenylphoshine oxide. The utility of macroporous polymer sorbents impregnated by these podands for extracting and concentrating rare earth(III) and scandium(III) ions from aqueous perchlorate solutions was demonstrated.     

Heavy-metal extraction capability of chalcogenoic aminophosphines derived from 1-amino-4-methylpiperazine

Aminophosphine of the type (Ph₂PNHR) derived from 1-amino-4-methylpiperazine and its chalcogen derivatives (Ph₂P(X)NHR X = S, Se) were used as ligands in solvent extraction of metal picrates such as Cu²⁺, Ni²⁺, and Pb²⁺ from the aqueous to the organic phase. Influence of parameters such as pH of the aqueous phase, ligand concentration in the organic phase, and concentration of the extractant extracted from the aqueous to the organic phase was investigated to determine the ligands’ ability to extract metal ions. Metal picrate extraction was investigated at 25°C using UV-VIS spectrophotometry in dichloromethane in the absence and in the presence of Ph₂PNHR and chalcogenides. The extraction results revealed that the extraction percentage of Cu²⁺, Ni²⁺, and Pb²⁺ metals was much higher at lower pH values, indicating an acidity dependent complexation equilibrium.     

Extraction of polyvanadates by means of amines

The present paper is aimed at obtaining quantitative information on the extraction of polyvanadates from aqueous solutions with benzene solutions of tri-n-octylamine and Primene JMT with respect to initial pH value of aqueous solution and the ratio of volumes of the organic and aqueous phase. The predominant species in acidic solutions at concentrations in excess of 0.01 M are decavanadates. The extraction equilibria were studied within the range of pH 2–4. At this concentration of sulfuric acid the species V₁₀O₂₆(OH)^4– and V₁₀O₂₇(OH)^5– prevail. Supposing that the nonideality of the aqueous phase does not play an important role and that the activity coefficient of the amine sulfate remains constant, the nonideal behavior of the extraction system can be explained by the hydration of complexes in the organic phase. On the basis of suggested reactions and mass balance equations the comparison of experimental and calculated equilibrium data was done.