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 of silver/I/ with 2,4-dihydroxy-acetophenone thiosemicarbazone

The solvent extraction of silver/I/ is carried out in acetic acid-sodium acetate buffer solution at pH 5.0 by 2,4-dihydroxyacetophenone thiosemicarbazone /DATS/. Ethyl acetate has been used as a solvent and is found that single extraction is sufficient to remove silver/I/ completely from the aqueous phase. Silver/I/ forms 11 complex /metalreagent/ with DATS. The effect of diverse ions on the extraction of silver/I/ has been investigated.     

Solvent extraction of Cu/II/ with 1,2,3-benzotriazole into chloroform

1,2,3-Benzotriazole/1,2,3-BT/ has been used for the extraction of Cu/II/ into chloroform. The effect of various parameters on the extraction coefficient of Cu/II/ was evaluated. The stoichiometry of metal:reagent, determined by the method of substoichiometric extraction and slope ratio was found to be 12. Separation factor for a number of elements in the extraction of Cu/II/ has been evaluated.     

Extractive separation of Cu<Superscript>2+</Superscript>–Co<Superscript>2+</Superscript> and Ni<Superscript>2+</Superscript>–Co<Superscript>2+</Superscript> mixtures using <Emphasis Type="Italic">N</Emphasis>-salicylideneaniline

A study on the extraction of copper(II), cobalt(II), and nickel(II) from solutions containing ions of both metals with N-salicylideneaniline(SAN) in chloroform has been realized. Distribution of the metal ions in wide range of pH has been studied. Extraction of copper(II) was always favored over that of cobalt(II). Extraction of copper(II) from binary metal solution is selective and it can be quantitatively separated from cobalt(II). The equilibrium constant of the extraction of cobalt and nickel from an aqueous solution containing both metals using SAN were evaluated. The separation factors for cobalt and nickel were expressed as a function of the distribution of nickel and cobalt. From these results, salicylideneaniline is an adequate extractant for extractive separation of such mixtures.     

Solvent extraction of Ni/II/ with isonitrosobenzoylacetone into chloroform

A method has been developed for the quantitative extraction of Ni/II/ with isonitrosobenzoylacetone /HINBA/ into chloroform. The effect of various parameters on the extraction coefficient value such as pH, time of equilibration, effect of solvents, anions, cations etc. have been studied. The stoichiometry of the metal: reagent determined by the method of substoichiometric extraction and slope ratio method was found to be 12. Decontamination factors for many elements in the substoichiometric extraction of Ni/II/ were also evaluated.     

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 Zn/II/ with 1,2,3-benzotriazole into n-hepatanol

A method based on solvent extraction has been developed for the radiochemical separation of Zn/II/ from other elements employing 1,2,3-benzotriazole as a complexing agent and n-heptanol as an extractant. Optimum conditions for the extraction have been established. The effect of various anions and cations on the extraction coefficient value of Zn/II/ has been studied. The stoichiometry of the metal to reagent determined by the method of substoichiometric extraction and slope-ratio method was found to be 12.     

Synergistic extraction of cobalt(II) with resacetophenone oxime in the presence of heterocyclic nitrogen and organophosphorous compunds

Equilibrium distribution coefficients have been determined, for the extraction of cobalt(II) with resacetophenone oxime as a function of pH and reagent concentration at ambient temperature. RAPOX forms simple 12 chelate with cobalt(II). Synergistic extraction was observed with pyridine and its methyl derivatives and some organophosphorous compounds. From the extraction equilibrium data, the adduct formation constants of 12 chelate to adducting ligand adducts were evaluated.     

Radiochemical separation of Pd/II/ with isonitrosobenzoylacetone in benzene

The reagent isonitrosobenzoylacetone /HINBA/ was used for the radiochemical separation of Pd/II/ employing solvent extraction. Based on various parameters such as effect of molarity of the acid, time of equilibration and effect of various solvents; the extraction coefficient value of Pd/II/ has been evaluated. The stoichiometry of the metal to reagent was determined by the substoichiometric extraction and slope-ratio method and was found to be 12.     

High performance liquid chromatographic separation and UV determination of cobalt, copper iron and platinum in pharmaceutical preparations using bis(isovalerylacetone)ethylenediimine as complexing reagent

The reagent bis(isovalerylacetone)ethylenediimine(H₂IVA₂en) has been examined for HPLC separation and UV determination of cobalt, copper, iron and platinum using off-line precolumn derivatization and extraction in chloroform. The complexes of cobalt(II), cobalt(III), iron(II), iron(III) and the reagent have been subsequently separated on a Microsorb C-18 column. The complexes were eluted isocratically using ternary mixtures of methanol/water/acetonitrile. Detection was achieved by UV monitoring. Detection limits for Co(II), Co(III), Fe(II) and Fe(III) were 2.5–5.0 ng/injection, based on 0.5–1.0 g/ml with 5 l/injection. The concentration of cobalt(II) and cobalt(III) in aqueous solution have been determined. The presence of oxovanadium(IV), platinum(II), and nickel(II) did not affect the determinations. The HPLC method developed has been applied to the determination of cobalt, copper, iron and platinum in pharmaceutical preparations at the 30 g/g to 15 mg/g level and the obtained results were compared to those of atomic absorption spectrometry.     

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 Mn/II/ with 2-propionyl, 1-naphthol oxime/2-PRONAPOX/ into chloroform

A rapid method has been described for the quantitative extraction of milligram amounts of Mn/II/ with 2-PRONAPOX into CHCl₃. The extraction coefficient /E/ of Mn/II/ between CHCl₃ and aqueous solution containing 0.2M NH₄Cl shows a maximum value of E=143 at pH 10.5. The percentage extraction is better than 98% in the pH range from 9 to 11 and an equilibration time of 6 min. The effects of anions and cations have been studied. The stoichiometry of metal: reagent determined by substoichiometric extraction and slope ratio method is found to be 12. The decontamination factors for most of the elements are better than 10⁴ in the substoichiometric extraction of Mn/II/.     

Radiochemical separation of Mn/II/ with 1,2,3-benzotriazole into 1-octanol employing solvent extraction technique

1,2,3-Benzotriazole /1,2,3-BT/ has been used for the radiochemical separation of Mn/II/ employing solvent extraction technique. Based on various parameters such as pH effect, time of equilibration and effect of various solvents, etc. the ideal conditions for the extraction of Mn/II/ was evaluated. The stoichiometry of the metal to reagent was determined by the substoichiometric extraction and slope-ratio method and found to be 12. The effect of anions on the extraction value of Mn/II/ revealed that a large number of anions do not interfere. Separation factors for various elements were also studied and the extraction found to be selective.     

Solvent extraction study of cobalt(II) with 8-mercaptoquinoline

Equilibrium distribution coefficients have been determined for the extraction of cobalt(II) with 8-mercaptoquinoline as a function of pH and reagent concentraton at ambient temperature. The extractable complex is a diadduct, i. e. two molecules of the reagent are coordinated to the cobalt(II) chelate. The adduct formation constant in chloroform and the overall formation constant in the aqueous phase have been determined. Pyridine and its methyl derivatives were found to enhance the extraction of Co(II) into chloroform in the presence of 8-mercaptoquinoline. From the extraction equilibrium data, the adduct formation constants of 12 chelate to nitrogen base adducts were evaluated. The special role of steric factors is discussed.     

Transition metal complexes with 2-methyl-, 3-methyl-, and 4-methyl-piperidine dithiocarbamate as ligands

Summary A new series of manganese(III), cobalt(II), nickel(II), zinc(II), cadmium(II) and mercury(II) complexes with monomethylsubstituted dithiocarbamates as ligands has been synthesized and studied. Their structures are discussed in relation to their spectroscopic, magnetic and thermal properties. The dithio-ligands exhibit bidentate behaviour acting as S,Sdonors in all the complexes. In the far i.r. region particular attention is paid to a comparison of the spectra of the octahedral complexes with those of the other metal derivatives (12 metal to ligand molar ratio). The e.s.r. spectra are indicative of aD _2h symmetry in the cobalt(II) complexes.     

Liquid�Cliquid extraction studies with 4,4��-biphenylene-spaced bis-��-diketones

4,4??-biphenylene spaced lipophilic bis-??-diketone ligands of the type 4,4??-bis(RC(O)CH₂C(O))C₁₂H₈ (R = Pr, Ph, hexyl, octyl, nonyl) have been prepared and used for the liquid?Cliquid extraction of d-block metal ions. These ligands are expected to interact with divalent metal ions to form charge-neutral trinuclear metallocycles of type [M₃(L ³ )₃(solvent)] as has been demonstrated with the previously reported derivative of H₂ L ³ (R =  ^t Bu), the X-ray structure of which is reported. Liquid?Cliquid extraction studies were performed in a two-phase water/chloroform system employing a radiotracer technique for cobalt(II) and zinc(II). These experiments involved the systematic variation of ligand, metal and 4-ethylpyridine concentrations to probe the stoichiometries of the species extracted. Synergistic extraction was observed when 4-ethylpyridine was present with the ligand in the organic phase. Competitive extraction studies demonstrated the ligands are highly selective for copper(II) over cobalt(II), nickel(II), zinc(II) and cadmium(II).     

Reversed phase partition chromatographic separation of divalent copper with N-n-octylaniline on silica gel

A novel separation method was developed for the extraction and chromatographic separation of copper(II). The quantative extraction of 25.0–125.0 μg copper(II) has been observed from 0.05 to 0.25 mol/L of ascorbic acid at pH 9.0–12.0 with 0.087 mol/L N-n-octylaniline (liquid anion exchanger) coated on silica gel at a flow rate of 1.0 ml/min. The extracted metal ion has been recovered by eluting with 25.0 ml of 1.0 mol/L hydrochloric acid and determined spectrophotometrically by rubeanic acid method. The various influencing parameters viz. acid concentrations, reagent concentration, eluates effect of pH, and effect of flow rate on extraction were studied. The method is free from large number of interferences from cations and anions. A scheme for mutual separation of copper(II), gold(III) and bismuth(III) has been developed. Copper(II) has been separated from ayurvedic (Herbal) medicine and synthetic mixtures corresponding to alloy. The log–log plot of N-n-octylaniline concentration versus the distribution coefficient indicates that the probable extracted species is [.     

Metal complexes of sulphur-nitrogen chelating agents. Part 14. Nickel(II), palladium(II), copper(II), cobalt(II), and cobalt(III) complexes of the tetradentate schiff bases having ONNS donor sites

Summary Complexes of nickel(II), palladium(II), copper(II), cobalt(II), and cobalt(III) with methyl-2-(-salicylaldiminoethyl)-cyclopent-1-en-dithiocarboxylate (H₂L¹) and methyl-2-(-salicylaldiminoisopropyl)cyclopent-1-en-dithiocarboxylate (H₂L²) have been prepared. They contain the donor sites ONNS. The metal(II) ions from neutral, monomeric square planar chelate complexes. The cobalt(III) complexes [CoL¹-(H₂O)₂]X (X=Cl or ClO₄) appear to betrans-diaqua-species. All compounds have been characterized by a number of physico-chemical methods.     

Simultaneous determination of iron(III) and cobalt(II) withN-phenylcinnamohydroxamic acid and thiocyanate by extraction and spectrophotometry

Simple, precise, sensitive, and highly selective methods for the separate determination of iron(III) and cobalt(II) and for the simultaneous determination of both metal ions are described. Iron(III) and cobalt(II) react with thiocyanate in the presence ofN-phenylcinnamohydroxamic acid (PCHA) to form pinkish red and blue coloured complexes, respectively. Both the iron(III) and cobalt(II) complexes having stoichiometric composition of 122 (FeSCN^–PCHA) and 14 (CoSCN^–), respectively, are quantitatively extractable into ethylacetate from 0.5–1.5 M hydrochloric acid solutions. The spectra of iron(III) and cobalt(II) complexes in the visible region exhibit absorption maxima at 495 and 625 nm, respectively. The coloured systems obey Beer's law in the concentration range of 0.2–4.0g/ml of iron and 2–40g/ml of cobalt. The effects of foreign ions and of various experimental parameters were studied to establish the optimum conditions for the extraction and determination of iron and cobalt. The methods have been applied successfully to the analysis of blood, vitamin B₁₂, and standard steels for iron and cobalt.     

Solvent extraction of zinc/II/ with sulphoxides: Theoretical analysis of extraction behaviour

This paper describes a theoretical method for analyzing the behaviour of⁶⁵Zn during solvent extraction from ammonium thiocyanate solutions with dialkyl sulphoxides. The mechanism of extraction of Zn/II/ from thiocyanate medium by sulphoxides may be represented by the following general equation: $$xM_{aq}^{m + } + ySCN_{aq}^ - + zS_{org} \rightleftharpoons [M_x /SCN/_y ]^{mx - y} .zS_{org} $$ where M^m+ is the metal ion and S is the extractant. Expressions for the distribution coefficients were derived taking into account complexation of the metal in the aqueous phase by inorganic ligands and also the dissociation of the extracted ion-pairs in the organic phase. Using these expressions, the values of the extraction constants were determined by a least-squares fit with the experimental extraction data. From these extraction constants, the various species extracted into the organic phase were resolved. The influence of the metal concentration, temperature and the diluent on the extraction of Zn/II/ has been investigated.