Solvent extraction of yttrium(III) by TBP from acidic organic-aqueous solutions

Extraction by benzene solutions of TBP of carrier-free⁹⁰Y(III) from mixed aqueous-organic nitrate and perchlorate solutions was studied with special respect to the S-shaped D_Y versus acid concentration plots observed in aqueous systems. The presence of organic solvents in the aqueous phase enhanced the extraction of Y(III) and also influenced the shape of the D_Y vs. acid concentration plots in that the minimum was shifted towards lower acid concentration, became less pronounced, and eventually vanished completely.     

Solvent extraction of Cobalt/II/ from thiocyanate solutions by sulphoxides

The extraction of cobalt/II/ from ammonium thiocyanate solutions by di-n-pentyl sulphoxide /DPSO/, di-n-octyl sulphoxide /DOSO/ and their mixtures in carbon tetrachloride has been studied. The species extracted were found to be Co/SCN/₂. 4S /where S=DOSO or DOSO/. Synergic effects have been observed which are ascribed to the formation of mixed ligand metal complexes. The influence of the metal concentration, temperature and the diluent on the extraction of cobalt/II/has been investigated.     

Solvent extraction of lanthanum(III) from sulphuric acid solutions by Primene JMT

The distribution of lanthanum(III) between aqueous H₂SO₄ solutions and Primene JMT in the organic phase is described. The dependence of the extraction on acidity, extractant concentration and type of diluent was investigated. Aggregation numbers are calculated and a mechanism for the extraction is suggested. The separation of thorium(IV) from lanthanum(III), cerium(III) and cerium(IV) is outlined.     

Solvent extraction of lanthanoid/III/ with 18-crown-6 from aqueous trichloroacetate solutions to 1,2-dichloroethane

Extraction behaviour of lanthanoid/III/ has been investigated by using 18-crown-6/CR/ as a neutral microcyclic ligand, trichloroacetate/TCA^–/ as an anionic counter ion, and 1,2-dichloroethane as an organic solvent. From the equilibrium studies, the extractable complex such as LnCR³⁺ was found for La/III/, Ce/III/, Pr/III/, Nd/III/, Sm/III/, and Eu/III/ and also the formation of Ln/CR/ ₂ ³⁺ complexes was suggested for Tb/III/, Tm/III/, and Lu/III/. The extractability of lanthanoid/III/ steeply decreased with increase in the atomic number. This order of extractability was a reverse trend compared with that in many other extraction systems reported so far. Very high separation factors especially among light lanthanoid/III/ were observed.     

Solvent extraction of Co/III/ with 1, 2, 3-benzotriazole into n-butanol

A new and rapid method has been developed for the quantitative extraction of Co/III/ with 1, 2, 3-benzotriazole into n-butanol. The extraction coefficient value of Co/III/ between n-butanol and an aqueous 5% solution of 1, 2, 3-BT in 2M sodium acetate-acetic acid buffer showed a maximum value of E=280 at pH 8.5. The effect of various other parameters on the extraction coefficient of Co/III/ such as solvents, anions, cations etc. has also been studied. The stoichiometry of the metal: reagent determined by the method of substoichiometric extraction and slope-ratio method was found to be 12. The separation factors studied for most of the elements were found to be better than 10³.     

Solvent extraction of europium from aqueous-organic solutions by solvating extractants

The partition of Eu(III) between benzene containing solvating extractants (TBP, TOPO, dioctylsulfoxide) and aqueous nitrate, perchlorate and thiocyanate solutions containing various organic solvents miscible with water (alcohols, acetone, acetonitrile, ethylene glycol, dimethyl sulfoxide and dimethylformamide) was investigated. Depending on the specific extraction system, the presence of organic solvents in the mixed phase showed various effects on the distribution ratio of Eu(III). These were discussed in terms of solute-solvent interactions. The results in the systems containing dimethylformamide and dimethyl sulfoxide indicated complexation of Eu(III) with these solvents in the polar phase.     

Solvent extraction of some metals from aqueous solutions

The results for the extractions of divalent (manganese, cobalt, zinc and cadmium) and trivalent (gallium and indium) metals and hexavalent uranium from aqueous solutions by various extractants such as organophosphorus compounds (tributyl phosphate, trioctylphosphine oxide, di-(2-ethylhexyl)phosphoric acid and 2-ethylhexyl 2-ethylhexylphosphonic acid), sulfur-containing compound (dihexyl sulfoxide), high-molecular weight amines (trioctylamine and trioctylmethylammonium chloride) and 7-alkylated hydroxyquinoline (7-(5,5,7,7-tetramethyl-1-octen-3-yl)-8-hydroxyquinoline are discussed in the viewpoint of separation chemistry.     

Solvent extraction of Co/II/ with isonitrosobenzoylacetone into chloroform

A rapid and selective method has been developed for the extraction of Co/II/ with isonitrosobenzoylacetone into chloroform. The effect of various parameters on the extraction coefficient value such as effect of pH, time of equilibration, effect of various cations and anions have been evaluated. The stoichiometry of metal to reagent determined by the method of substoichiometric extraction was found to be 12. It was further supported by the slope ratio method.     

Solvent extraction of reduced technetium from mineral acid solutions

The extraction of reduced^99mTc with 5,7-dichloroxine, tributyl phosphate (TBP) and 1-phenyl-3-methyl-4-benzoyl-pyrazolone-5 (PMBP) from HCl−LiCl mixtures has been studied. A mechanism of extraction is proposed and the stability of the chlorocomplexes of technetium (V) in a hydrochloric and—lithium chlorid—perchloric acid mixture has been established using extraction data of^99mTc and spectrophotometric measurements with⁹⁹Tc.     

Solvent extraction of Fe(III) by di-(2-ethylhexyl)phosphoric acid from phosphoric acid solutions

The extraction of iron(III) from aqueous phosphoric acid was studied using di-(2-ethylhexyl)phosphoric acid and trioctylphosphine oxide in nonaromatic hydrocarbon diluent. Distribution ratios have been investigated as a function of concentration of iron(III), phosphoric acid concentration, extractant concentration and extraction temperature. The apparent enthalpy change for the extraction reaction has been calculated from the temperature dependence data. It was found that the extractant dependency for iron(III) is first power indicating hydrolysis of iron(III) in the aqueous phase.     

Solvent extraction of silver/I/ from dilute cyanide solutions with 2,4-dihydroxyacetophenone thiosemicarbazone

The solvent extraction of silver/I/ has been carried out in 0.5M nitric acid in presence of cyanide by 2,4-dihydroxyacetophenone thiosemicarbazone /DATS/. Ethyl acetate has been used as a solvent and quantitative recovery is made possible with 12.5-fold excess of the reagent in a single extraction. In this medium silver/I/ forms a 22 complex /metal:ligand/ with DATS. The effect of diverse ions on the extraction of silver/I/ has been investigated.     

Solvent extraction separation of T1/I/ from T1/III/ with sulphoxides

A method for the separation of microgram quantities of T1/I/ and T1/III/ from hydrochloric acid solutions has been developed. T1/III/ was extracted as HTlCl₄ into benzene by di-n-pentyl sulphoxide /DPSO/ and di-n-octyl sulphoxide /DOSO/. Conditions for the effective extraction of T1/III/, free from T1/I/, have been worked out.     

Solvent extraction of zirconium from hydrochloric acid solutions by sulphoxides and their mixtures

The solvent extraction of zirconium from HCl solutions by dipentyl sulphoxide (DPSO), dioctyl sulphoxide (DOSO), tributyl phosphate (TBP), and their mixtures in various solvents has been studied. At a given H⁺ strength, the extraction coefficient η of the metal increases with an increase in Cl⁻ activity whereas it is almost independent of H⁺ at constant Cl⁻. Under otherwise identical conditions, η increases with an increase in the extractant concentration but is virtually independent of the metal ion concentration over a wide range. The species extracted are ZrCl₄·DPSO, ZrCl₄·DOSO, and ZrCl₄·2TBP. In the case of mixtures, the slope of the log η−log M extractant plot for one component decreases with an increase in the concentration of the second component, the lines crossing at a common point. Extraction is favoured by solvents of low dielectric constant. It is possible to separate zirconium from thorium and uranium by solvent extraction with sulphoxides.     

Solvent extraction of tetraphenylarsonium ion pairs from mixed aqueous-organic solutions

Ion pairs of tetraphenylarsonium cation with iodide, bromide, and perrhenate anions were extracted into chloroform from mixed aqueous-organic solutions. The extraction of these ion pairs was found to increase in the presence of polar aprotic solvents in the mixed aqueous-organic phase. This effect was correlated with literature data on free energy of transfer of the Ph₄As⁺ ion, and ascribed to ion pair/solvent and/or ion/solvent interactions in the organic phase.     

Solvent extraction of Au/III/ with 1,2,3-benzotriazole into n-butanol

Aqueous 1,2,3-benzotriazole/1,2,3-BT/ has been used for the extraction of Au/III/ from acidic medium into n-butanol. The extraction of Au/III/ was found to be better than 98% over the pH range 2.0–7.0 and an equilibration time of 2.0 min. The effect of anions and cations on the extraction coefficient has been studied. The stoichiometry of metal: reagent determined by the slope ratio method was found to be 13. Separation factor for many elements in the extraction of Au/III/ has been evaluated.     

Solvent extraction of In/III/ with 1,2,3-bezotriazole into n-heptanol

Aqueous 1,2,3-benzotriazole has been used for the extraction of In/III/ in alkaline medium. The extraction of In/III/ was found to be better than 99% over the pH range 5.0–10.0 and an equilibration time of 2.0 min. The effect of anions and cations on the extraction coefficient has been studied. The stoichiometry of metal: reagent determined by the slope-ratio method was found to be 13. Separation factors for around 20 elements were better than 10³.     

Solvent extraction of Fe/III/ with 1,2,3-benzotriazole into n-heptanol

A new and rapid method has been developed for the quantitative extraction of Fe/III/ with 1,2,3-benzotriazole /1,2,3-BT/ into n-heptanol. The extaction coefficient value of Fe/III/ between n-heptanol and an aqueous 1% solution of 1,2,3-BT was found to be better than 99% over the pH range of 7.3 to 8.0 for an equilibration time of 2.0 min. The effect of various other parameters on the extraction coefficient value of Fe/III/ such as solvents, anions and cations etc. has also been studied. The stoichiometry of the metal: reagent determined by the method of substoichiometric extraction and slope-ratio method was found to be 13. Separation factors for most of the elements studied were better than 10³.     

Solvent extraction of alkali metal ion-pairs into nitrobenzene from aqueous-organic solutions

Solvent extraction of¹³⁷Cs,⁸⁶Rb and⁴²K by dipicrylaminate and tetraphenyl borate into nitrobenzene was studied from solutions containing various solvents miscible with water. In all cases the distribution ratios of alkali metals were lower in mixed solutions than in water. In discussing the results, water structure, ion-association, solubility of Cs(I) ionpairs, ionic strength, and organic phase effects were taken into account. Part III in the series Solvent Extraction of Ion-pairs. Part II. Ref.⁸     

Oxidation of hydroxynaphthalenes by means of Co(III) acetate

1,4-Dihydroxynaphthalene can be quantitatively oxidized to 1,4-naphthoquinone with Co(III) acetate in glacial acetic acid. Analytical determination can be carried out both directly potentiometrically, as well as indirectly using excess of the oxidant and back titrating the unconsumed amount of the reagent with Fe(II) sulfate.