EXTRACTION AND SEPARATION OF ZIRCONIUM(IV) WITH 3-HYDROXY-2-METHYL-1-PHENYL-4-PYRIDONE

ABSTRACT The extraction of zirconium(IV) from aqueous hydrochloric, sulphuric and perchloric acid solutions with 3-hydroxy-2-methyl--1-phenyl-4-pyridone (HX) dissolved in chloroform is described. Perchlorate and thiocyanate ions show a synergistic effect on zirconium extraction with HX. The synergistic effect of thiocyanate is stronger than the effect of perchlorate.

The composition of the extracted zirconium(IV) complexes is studied and a simple and rapid method for the separation of zirconium from niobium is described.     

SYNERGISTIC SOLVENT EXTRACTION OF TRIVALENT LANTHANIDES AND ACTINIDE BY MIXTURES OF 1-PHENYL-3-METHYL-4-BENZOYL-PYRA2ALONE-5 AND NEUTRAL OXO-DONORS

ABSTRACT

The synergistic solvent extraction of trivalent lanthanides such as La, Eu and Lu and a trivalent actinide, Am, has been studied with mixtures of 1-phenyl-3-methyl-4-benzoyl-pyrazalone-5 (HPMBP) and bis(2-ethylhexyl) sulphoxide (B2EHSO) or octyl(phenyl)-N,N-di isobutylcarbamoylmethylphosphine oxide (CMPO) in xylene. The extraction data have been analysed by both graphical and theoretical methods by taking into account aqueous phase speciation and all plausible complexes extracted into the organic phase. With HPMBP alone all the trivalent metal ions form M(PMBP)₃.HPMBP type self adducts. With B2EHSO as a neutral donor, the synergistic adduct species are M(PMBP)₃.B2EHSO and M(PMBP)₃.2 B2EHSO (where M = La, Eu, Lu and Am), whereas with CMPO as a neutral donor the only complex extracted into the organic phase is M(PMBP)₃.CMPO. The synergistic extraction constants of the above species which were deduced by non-linear regression analysis are found to increase monotonically with decreasing ionic radii of these metal ions.     

EXTRACTION AND COMPLEX FORMATION OF PLUTONIUM(IV) WITH 1-PHENYL-2-METHYL-3-HYDROXY-4-PYRIDONE

Abstract

At a ionic strength of 1.0 and mineral acid concentrations of 0.1 to 1M, l-phenyl-2-methyl-3-hydroxy-4-pyridone (HX, 0.001 to 0.01M in chloroform) extracts plutonium(IV) effectively from nitrate solutions, somewhat less effectively from perchlorate solutions and markedly less effectively from chloride solutions. The extractant distributes between the phases in a monomeric form, as an undisso-ciated molecule and a cationic species. The stoichiometries of the complexes extracted from the respective ionic media are PuX₂(NO₃)₂, PuX₃(Clo₄)₂HX and PuX₂(Clo₄)₂.HX, and PuX₂Cl₂.     

SYNERGISTIC SOLVENT EXTRACTION OF LANTHANIDES WITH MIXTURES OF 1-PHENYL-3-METHYL-4-BENZOYL-PYRAZOL-5-ONE AND ALIQUAT 336

The solvent extraction of Pr(III),Gd(III) and Yb(III) With 1-phenyl-3-methyl-4-benzoyl-pyrazol-5-one (HP) and Aliquat 336(QCl) in CCl₄.C₆H₆ and CHCl₃, has been studied.The composition of the extracted species has been determined as LnP₄ ^?.Q⁺ (Ln=Pr,Gd and Yb).The values of the equilibrium constants have been calculated. The extraction mechanism has been discussed.     

SOLVENT EXTRACTION OF HAFNIUM( IV) WITH 3-HYDR0XY-2-METHYL-1-PHENYL-4-PYRIDONE

The extraction of hafnium(IV ) from aqueous hydrochloric, sulphuric and perchloric acid solutions with 3-hydroxy-2-methyl--1-phenyl-4-pyridone(HX) dissolved in chloroform is described. Perchlorate and thiocyanate ions show a synergistic effect on hafnium extraction with HX. Hafnium can be quantitatively extracted with HX from more acidic solutions and with less excess of HX if the extraction is carried out from a hydrochloric, sulphuric or perchloric acid solution containing an excess of perchlorate or thiocyanate ions. A mixed Hf-NCS-HX complex is more stable than a mixed Hf-ClO₄-HX complex and thiocyanate ions show a stronger synergistic effect than perchlorate ions.     

SOLVENT EXTRACTION OF METALS WITH 4-DINITROBENZOYL-2, 4-DIHYDRO-5-METHYL-2-PHENYL-3H-PYRAZOL-3-ONE (DMPP)

ABSTRACT

The mechanism of the extraction of copper (II), nickel (II), cobalt (II) and thorium (IV) from aqueous buffer media with 4-dinitrobenzoyl1-2, 4-dihydro-5-methyl-2-phenyl-311-pyrazol-3-one (DMPP) in benzene has been investigated. The values of log K^*where K^*refers to the extraction equilibrium Mn⁺+-nHL ? MD_n+ nH⁺are Cu(II)& lpar; + 0.3), Co(II) (?6.65), Ni(II) (?5.04) and Th(IV) ( + 6.1). Solid complexes synthesized have the composition CuL₂· 2H₂O, NiL₂· 2H₂O and ThL₄respectively (L = anion of the ligand). DMPP seems to be superior to the corresponding 4-benzoyland 4-nitrobenzoyl derivatives of 2,4-dihydro-5-methyl-2-phenyl1-3 H-pyrazol1-3-one (MPP) and also better than thenoyltrifluoroacetone, the popularly employed fluorinated β-dike tone in the system investigated.     

SYNERGISTIC EXTRACTION OF CADMIUM AND ZINC WITH 1-PHENYL-3-METHYL-4-BENZOYLPYRAZOL-5-OL AND n-DODBCYLAMINE MIXTURES,EMULSION FORMATION.

The synergistic extraction of zinc and cadmium (M^2*) from sulphate, nitrate and perchlorate media with mixtures of 1-phenyl-3-methyl-4-benzoylpyra2ol-5-ol (HL) and n-dodecylammoniura salts (DDAH^*,X^?) in toluene has been studied. In sulphate medium, the lipophilic ammonium pyrazololate (DDAK^*L^?) is the predominating ammonium species : the synergy observed can be considered as the addition of (DDAH^*,L^?) on HL₂ perchlorate and nitrate media, the amphiphilic ammonium salts {DDAH^*, CIO₄?) and (DDAH⁺N0₃ ^?) predominate, leading to the formation of an aqueous emulsion in equilibrium with a clear organic phase. Metal distribution curves show that the formation of the lipophilic synergistic species (DDAH⁺ML₂ ^?) results from a X^?/ML₃ ^? exchange in the interfacial region between the aqueous and the organic phase. The addition of n-octanol or 4-nonylphenol in the organic phase turns the emulsion into a micro-emulsion whereas the substitution of toluene by chloroform largely decreases the emulsion stability.     

EXTRACTION OF TITANIUM(IV) BY MIXTURES OF MONO- AND DH(2-ETHYLHEXYL) PHOSPHORIC ACID ESTERS

ABSTRACT

Solvent extraction of titanium(IV) from hydrochloric acid solutions by mixtures of mono- and di-2-ethylhexyl phosphoric acid esters (MEHPA and DEHPA) has been investigated as a function of HC1 concentration in the aqueous phase and extractants concentration in the organic phase

It was found that MEHPA extracts Ti, 3 orders of magnitude more efficiently than DEHPA. Efficiency of extraction by MEHPA does not depend on acid concentration in the aqueous phase in the range of 0·1 – 8·8 mole/Kg. As a rule Ti/MEHPA ratio in the complex is 1/2. At low aqueous phase acidities (0·1–1·0 mole/Kg HCl) formation of six- (or eight-) coordinate bidentate hydrated Ti(IV)-2MEHPA complexes is suggested. At acidities above 7·0 mole/Kg HC1 titanium forms tridentate six- (or eight-) coordinate complexes. At medium acidities (2·0–6·0 mole/Kg HCl) mixtures of these complexes are formed. Prolonged mixing of the phases or aging of the organic phase leads to dehydration and to transformation of bidentate to tridentate Ti-2MEHPA complexes. Ti-2MEHPA complexes are colorless

At ratios Ti/MEHPA<0·5 formation of Ti-MEHPA hydrated or solvated complex ions is suggested which form emulsion in the aqueous phase. These species slowly react with DEHPA and formation of Ti:MEHPA:DEHPA=1:1:2 complex is realized. This complex is yellow.     

SYNERGIC EXTRACTIONS OF INDIUM(III) FROM CHLORIDE AND PERCHLORATE MEDIA WITH 1-PHENYL-3-METHYL-4-ACYLPYRAZOL-5-0NES AND TRI-n-OCTYLPHOSPHINE OXIDE MIXTURES IN TOLUENE

ABSTRACT

The synergic mixtures of extractants HL + TOPO where HL = l-phenyl-3-methyl-4-acylpyrazol-5-one, acyl = benzoyl (HPMBP), thenoyl (HPHTP), lauroyl (HPMLP) and with TOPO = tri-n-octylphos-phine oxide, are studied by IR, PMR and 31P NMR spectroscopies and by liquid-liquid distribution analysis. In toluene solutions, the “acylpyrazolones” are, in fact, chelated 4-acyl-5-hydroxy-pyrazoles ; addition of TOPO weakens this intramolecular H-bond by formation of H-bonded (TOPO.HL) complexes (log Kc -?, 1.1) ; the chelate ring may be broken (HPHTP) or subsist (HPMBP, HPMLP) in these complexes. Solid HPMBP exists either as chelated 4-acyl-5-hydroxypyrazole (yellow solid, F = 92°C) or as “open” 4-acyl-5-hydroxypyrazole with strong intermolecular H-bonds (white solid, F = 1150C).

Extraction of indium with the extraction solvents studied, from CI /C10₄aqueous solutions.takes place according to the four-equilibria (x = 0 to 3) :

The constants K_xare determined : K_O? K₁> K₂> K₃; HPMBP is the best extractant in all cases. The HL - TOPO association has no influence upon these extractions     

EXTRACTION OF URANIUM(VI) AND VANADIUM(V) WITH 4-ADIPOYL AND 4-SEBACOYL DERIVATIVES OF BIS(1-PHENYL-3-METHYL-PYRAZOLONE-5) AND EFFECT OF DECANOL ON THE DISTRIBUTION BEHAVIOUR OF THESE METAL IONS

ABSTRACT

The liquid-liquid extraction of U(VI) and V(V) with 4-adipoylbis(l-phenyl-3-methyl-pyrazolone-5) (H₂AdP)′ and 4-sebacoylbis(l-phenyl-3-methyl-pyrazolone-5) (H₂SP) was studied in the presence and absence of decanol (DOH). The studies show that in the absence of DOH the extracted species were (U0₂) ₂(AdP) ₂ U0₂(HSP) ₂, V0₂(HAdP) and V0₂(HSP). Addition of DOH to the organic phase resulted in enhancement of the extraction of V(V) at high HCI concentrations but reduced the extraction of U(VI) due to a change in extraction mechanism. Subsequently, ion-pair complex species VO₂(HAdP)DOH₂ ⁺)₂CI_- and V0₂(HSP)(DOH₂ ⁺)₂.2CI^- were extracted. The extraction constants K_cx and pH_1/2 for the various extraction systems were determined and used for explaining the various extraction mechanisms observed.     

SPECTROSCOPY OF INDIUM(III) LIPOPHILIC SPECIES EXTRACTABLE FROM PERCHLORATE MEDIUM BY TWO 1-PHENYL-3-METHYL-4-ACYL-PYRAZOL-5-OLS AND TRI-N-OCTYLPHOSPHINE OXIDE*

ABSTRACT

With the aim of improving our knowledge about the extraction of indium from perchlorate media, by 1-phenyl-3-methyl-4-acyl-pyrazol-5-ols, “HL” ( acyl = benzoyl or thenoyl) and their mixtures with tri-n-octylphosphine oxide, “TOPO”, in toluene, synthetic and extraction organic phases, and extractable conplexes, have been studied by phosphorus-31 and proton NMR, and by IR spectroscopy.

As expected from the extraction equilibria, only one species is extracted by HL. It is identified as a tris-chelate by comparison with the synthesized complexes InL₃(H₂O)_z (z = 0, 2). The synergistic mixtures HL + x TOPO extract several species InL₃(TOPO)_n ( n.≥. 0, depending upon x). A coordination number of In higher than 6 is suggested.

The only way to obtain strong In ? O = PR₃ bonds is the extraction of indium, therefore, the reaction:     

EXTRACTION OF INDIUM( III) FROM BROMIDE AND THIOCYANATE MEDIA WITH 1-PHENYL-3-HETHYL-1-BENZOYLPYRAZOL-5-ONE; EFFECT OF LIPOPHILIC AMMONIUM SALTS

1-phenyl-3-methyl-4-benzoylpyrazol-5-one (HL) in toluene extracts In(III) from ClO₄ ^?, (Br^?, CIO ClO₄ ^?, ) and Br^? media according to the extraction equilibria (1) and (2). Tri-n-octylmethylammonium bromide (B⁺Br^?) induces a medium synergic effect for Br^? and (Br^?,NO₃ ^?) media, which is cancelled in ClO₄ ^?medium. It corresponds to the extraction of (B⁺InBr_xL_4-x) ion pairs. On the contrary, from SCN^? or (SCN^?,ClO₄ ^?) media, In is extracted by HL according to only (1) and no synergism is obtained with tri-n-octylammonium salt.

These results are compared with those obtained with Cl^? and (C1^?,ClO₄ ^?) aqueous media. They are to a great extent explained by taking into account the complexing of In³⁺ by aqueous inorganic anions, the lipophilicity of the diverse species and the anionic exchanges in the B⁺X^? ion pairs.     

SYNERGIC EXTRACTION OF DIVALENT TRANSITION METALS WITH MIXTURES OF 1-PHENYL-3-METHYL-4 BENZOYL- PYRAZOL-5-ONE AND CROWN ETHERS IN PRESENCE OF ALKALI OR ALKALINE EARTH IONS

The extraction of divalent transition metals (M = Cu, Zn, Co, Cd) with mixtures of 1-phenyl-3-methyl-4-benzoylpyrazol-5-one (HL) and crown-ethers (E = B15C5, 18C6, DC18C6, DB18C6, DC24C8, DB24C8 with B = benzo, DB = dibenzo, DC = dicyclohexyl) in chloroform has been studied. From 1.0 M K aqueous solutions, EK.ML₃ ion pairs have been extracted with 18C6 - type crown ethers that have a good correspondence between their cavity size and the K⁺ diameter, _and with M = Co and Cd, metals with a higher stability of the ML- anion. With B15C5, which has a cavity size too small to accomodate K⁺, the synergic extraction of Co is explained by the formation of E₂.K.CoL₃. Both CoL₂E and EBa(CoL₃.) ₂ (E = DBl8C6)were extracted from 0.33M Ba(No₃ ) ₂. In all otHer experiments - extractions from 1.0M LiCl, NaCl, NaNO with B15C5     

THE EXTRACTION OF Eu(III) FROM ACIDIC MEDIA BY OCTYL(PHENYL)-N,N-DIISOBUTYL CARBAMOYLMETHYLPHOSPHINE OXIDE.

The extraction behavior of Eu(III) from nitric and hydrochloric acid By solutions of CMPO with and without TBP has been studied using mesitylene and dodecane as diluents. Compared to CMPO alone, the CMPO-TBP mixture shows a slight enhancement in the extraction of Eu(III) from nitric acid above 2M and lower DEu’ s from low acidity. The distribution ratios measured for Eu(III) between HN03 and CMPO-TBP in dodecane are higher than the corresponding values in mesitylene.Extractant dependency studies in the presence and absence of TBP show that at low HN03 concentrations, the extractant dependency curve obtained in the presence of TBP lies below the curve obtained in the absence of TBP. At high acidity, the opposite is observed. The extraction of Eu(III) from hydrochloric acid by CMPO-TBP in dodecane is much lower than from nitric acid. A comparison between CMPO and D2EHPA for Eu(III) extraction has been carried out.     

THE SOLVENT EXTRACTION OF ZINC FROM LITHIUM CHLORIDE BY ALIQUAT 336 CHLORIDE,BROMIDE AND IODIDE IN CHLOROFORM: AN ANALYTICAL INVESTIGATION

ABSTRACT

The extraction of zinc by Aliquat CI in chloroform is studied as a function of LiCl concentration. A plot of log D versus total [Cl] shows that log D increases sharply from 0-2 M LiCl, then remains constant over a considerable range of concentrations ( 2-8 M ), before shooting up again from 8-14 M. Further work is carried out at 4 M LiCl to determine the extraction equation, and quantitative aspects determined such as a plot of log D versus log [Aliquat Cl]_free, giving a ratio of 2:1 for extractant: metal, and the ratio [Cl / Zn]_extracted, which is 2.

In order to follow the exchange of halides across the interface, Aliquat Br and Aliquat I are used as extractants in chloroform to study the extraction of zinc chloride from 4 M LiCL Organic and aqueous phases are analysed for halides and zinc, and the ratio [ΔCl] / [Zn] in the organic phase determined to be 3 for both Aliquat Br and I at 4M LiCl, indicating extraction of ZnCl₃,' and not ZnCl₄ ² at this concentration. Further work with these extractants based on plots of log D versus log [Aliquat X]_free ( X = Br, I ) is presented and extraction equations are proposed for these extractants, which fit the data.

Extraction of zinc at 4 M LiCl by Aliquat Cl is then considered in terms of the extraction of the trichlorozincate (II) species, ZnCl₃,“, and the extraction constant determined.     

SOLVENT EXTRACTION OF COPPER(II) FROM CHLORIDE SOLUTIONS BY SOME PYRIDINE CARBOXYLATE ESTERS

n-octyl-3-pyridine carboxylate (NOPC), an analogue of the commercial reagent DS5443, was synthesized, and the stoichiometry of its reaction with copper(II) in chloride media was determined. At low metal loadings, copper(II) was extracted by the solvation reaction:

The factors affecting the separation of iron and copper from solutions containing copper(II),iron(II), and zinc(II)chlorides were determined in countercurrent extraction tests using DS5443.     

THE USE OF SOFT DONOR LIGANDS, 4-BENZOYL-2,4-DIHYDRO-5- METHYL-2-PHENYL-3H-PYRAZOL-3-THIONE AND 4,7-DIPHENYL-UO- PHENANTHROLINE,FOR IMPROVED SEPARATION OF TRIVALENT AMERICIUM AND EUROPIUM

The extraction of Am(ITI) and Eu(III) from aqueous 0.1?M NaClO4 using a mixture of 4-benzoyl-2,4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-thione (HBMPPT) and 4,7-diphenyl-l,10-phenanthroline (DPPHEN) was studied. Individually, neither the HBMPPT nor the DPPHEN in toluene showed any extraction capabilities for Am(III) or Eu(III) under the experimental conditions used in this study. Combination of the two ligands, however, yielded a synergistic system which showed a strong preference for Am(III) over Eu(III). Slope analysis indicated that the extracted species took the form M(BMPPT)3(DPPHEN) for both metal ions studied. The separation factor DAm/DEu was 190 at pH = 3.7, [HBMPPT] = 3.0 x 10-2, and [DPPHEN] = 2.7 x 10-3.     

LIQUID-LIQUID EXTRACTION OF METAL IONS BY NEUTRAL PHOSPHOR- AMIDES. PART I,EXTRACTION OF URANYL IONS FROM NITRATE AND SULPHATE MEDIA. EXAMINATION OF EXTRACTED SPECIES BY UV/V1S AND sip NMR SPECTROSCOPY.

ABSTRACT

The extraction of uranyl nitrate and uranyl sulphate from aqueous media by the neutral chelating diphosphoramides CH₃-N[P(OKNMe₂)₂] (NIPA) and its less hydrophilic homologues R-N[P(O)(NMe₂)₂]₂ (R = -C₁₂H₂₅ (OD1PA) or -C₁₆H₃₃ (OHDIPA)), diluted in CH₃NO₂ or toluene, has been studied. In the presei ce of HNO₃, NaNO₃, NaCl, and Na₂SO₄ as salting-out agents, extraction is generally excellent. Some of the extracted complex species have been identified by comparing their ³¹P NMR and UV/vis spectra with those of pure complexes of known structure. The results are compared with extractions using tri-n-butyl phosphate (TBP) as complexing agent.     

SOLVENT EXTRACTION OF ZINC(II) BY ORGANOPHOSPHORUS ACIDS COMPOUNDS FROM PERCHLORATE SOLUTIONS.

ABSTRACT

The extraction of zinc from perchlorate solutions at 0.1 mol.dm^?3 of ionic strength by di(2-ethylhexyl)phosphoric acid (HDEHP), 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester (HEH[EHP]) and di(n-octyl)phosphinic acid (H[DOP]) dissolved in toluene has been studied at 25 ° C.

The distribution coefficient was determined as a function of pH and HA concentrations and the data were analyzed both graphically and numerically using the computer program LETAGROP-DISTR.

The results showed that the data can be explained assuming the formation of ZnA₂(HA)₂ and ZnA₂HA in organic phase for all the extractants used. A correlation between extracted species and concentration of the various extractants has been found.

The predominance of the different species into the organic phase has been correlated with the difference between their extraction constants.

The anion of the ionic medium is not extracted into the organic phase.     

SOLVENT EXTRACTION OF URANIUM( VI) AND THORIUM( IV) FROM NITRATE MEDIA BY CARBOXYLIC ACID AMIDES

ABSTRACT

A series of nineteen N-alkyl carboxylic acid amides (R.CO.NHR') has been prepared, in which the alkyl groups R and R' have been varied in order to introduce different degrees of steric complexity into the compounds. A smaller number of N,N-dialkyl amides (R.CO.NR₂) and non-substituted amides (R.CO.NH₂) has also been prepared for comparison purposes. These amides were characterized by measurement of their boiling points, melting points, refractive indices and densities.|The solvent extraction of uranium(VI) and thorium(IV) from sodium nitrate media by solutions of the amides in toluene was studied. Increasing steric bulk of the alkyl groups R and R' was found to cause a marked decrease in the extraction of thorium, with a much smaller effect on the extraction of uranium, thus considerably enhancing the separation between these metals. Vapour pressure osmometry studies indicate that the N,N-alkyl amides are self-associated in toluene solution, with aggregation numbers up to about 2.5 for 0.6 M solutions at 35°C. In contrast, the N,N-dialkylamides behave as monomers under these conditions. The distribution ratios for the extraction of uranium and thorium show second- and third-order dependences, respectively, on the extractant concentration for both the N-alkyl and N,N-dialkyl amides.