Extraktion von 3d-Metallionen mit zweizähligen Sulfonamiden. I. Liganden mit Schwefel bzw. heterocyclisch gebundenem Stickstoff als zweitem Haftatom

Extraction of 3d-Metal Ions by Bidendate Sulfonamides. I. Ligands with Sulfur or Heterocyclic Nitrogen as a Second Donor Atom The properties of 2-acetylpyridine-p-toluensulfonylhydrazone (APSH - H), arensulfonylthioureas (I), and the esters of arensulfonylmonothiocarbamic acid (II) or arensulfonyldithiocarbamic acid (III) as extractants for the late 3d-metal ions are proved. APSH-H is comparable to the proprietary extractant LIX 34. But, because of the special structure of the corresponding 1,2-chelates, the pH_1/2-values of nickel(II) and cobalt(II) are ≈2 units lower. The pK_s-values, measured in dioxane-water mixtures (75 per cent v/v), increase in the order III < II < I. In aqueous solutions compounds of type III are acids of medium strength. In the case of compounds of type I the substituents of the non-sulfonated nitrogen have a strong influence on the pK_s-values (ΔpK_s = 4.6). Among the late 3d-elements, the ligands II and III extract only copper(II) (pH_1/2 ～2.7 or ～1.6), the ligands I extract zinc(II), cobalt(II), and nickel(II) as well, but not iron(II) and iron(III). The reasons of this unique behaviour are discussed.     

Solvent extraction of metals with commercial oxime extractant (LIX 622)

The extraction characteristics of some selected metals from an aqueous buffered solution by LIX 622, a commercial oxime extractant have been studied. The pH_1/2 values for extracting different metals with 5 v/v% LIX 622 extractant in methyl isobutyl ketone (MIBK) have been obtained. The order of extraction of metals with LIX 622 extractant as a function of pH_1/2 value is determined and results agree well with the order obtained using salicylaldoxime as chelating ligand for the extraction of these metals.     

Solvent extraction of metals using LIX26 extractant

Solvent extraction of some selected metals from an aqueous buffered solution by LIX26 extractant has been studied. The pH_1/2 values (at which 50% of metal ion is extracted) for extracting different metals by 1 v/v% LIX26 extractant in methyl isobutyl ketone have been obtained. The order of extraction of metals by LIX26 extractant as a function of pH_1/2 value is Pd(II)<Cu(II)<Sb(III)<Fe(II)<Co(II)<Zn(II)<Ni(II) <Pb(II)<Mn(II)<Cd(II).     

Identification of Components of Commercial Alkylsalicylaldoxime Based Reagents by GC–MS

A simple gas chromatographic-mass spectrometric (GC–MS) method for the identification of components present in alkylsalicylaldoximes based metal extractants LIX860, LIX622, LIX622N, Acorga PT5050 and Acorga P5100 is described. These reagents have been developed for removing copper in hydrometallurgical processes. The extractants were analyzed by GC–MS in the Full Scan mode without any derivatization step. 5-Nonylsalicylaldoxime in the extractants LIX622N, Acorga PT5050 and Acorga P5100 and 5-dodecylsalicylaldoxime in the extractants LIX622 and LIX860 were found to be present as a mixture of alkyl isomeric compounds. The extractant Acorga P5100 also contains a large amount of p-nonylphenol isomers whereas LIX622, LIX622N and Acorga PT5050 contain tridecyl alcohol isomers. In addition, the presence of small amounts of alkylphenol isomers was detected in all LIX reagents. The GC–MS study has revealed that the major fragmentation ions of the alkylsalicylaldoximes can be classified into two types: the molecular ion less C _n H_2n+1 and the molecular ion less C _n H_2n+1 and water. Cleavage of the benzylic bond predominates, resulting in the base peak. The identified compounds have been classified in different types that show different base peaks and the possible structures of the alkyl groups based on the substitution of the alpha-carbon are proposed.     

LIX 84 as an extractant for throium(IV), uranium(VI) and molybdenum(VI)

The extraction order of Th(IV), U(VI) and Mo(VI) based on pH_0.5 values is Mo(VI)>U(VI)>Th(IV). Quantitative extraction has been observed for U(VI) by mixture of 10% (v/v) LIX 84 and 0.1M dibenzoylmethane at pH 4.2 and by mixture of 10% LIX 84 and 0.05M HTTA in the pH range 5.5–7.3 and for Mo(VI) by 10% LIX 84 from chloride media at pH 1.5. The order of extraction of Mo(VI) from 1N acid solutions is HCl>H₂SO₄>HNO₃>HClO₄ and extraction decreases very rapidly with increase in the concentration of HCl as compared to that from H₂SO₄, HNO₃ and HClO₄ acid solutions. The diluents C₆H₆, CCl₄ and CHCl₂ are found to be superior ton-butyl alcohol and isoamyl alcohol for extraction of Mo(VI). Influence of concentration of different anions on the extraction of U(VI) and Mo(VI) has been studied. Very little extraction has been observed in case of Th(IV) by LIX 84 or its mixtures with other chelating extractants or neutral donors.     

Solvent extraction of Ni(II) from sulfate solutions with LIX 84I: flow-sheet for the separation of Cu(II), Ni(II) and Zn(II).

This paper reports on solvent-extraction studies of Ni(II) from sulfate solutions with LIX 84I (2-hydroxy-5-nonylacetophenoneoxime) as the extractant. The extraction of metal depends on the equilibrium pH of the aqueous phase and the extractant concentration. The transfer of metal follows a cation exchange-type mechanism: Ni2+ + 2HA --> NiA2 + 2H+. Extraction varies with the nature of the diluents. Temperature has no effect on the extraction of metal. The extraction behavior of associated metals clearly demonstrates the application of LIX 84I as the extractant for the separation of Cu(II), Ni(II) and Zn(II). Based on the results, a flow sheet of the process was developed.     

Komplexbildung und extraktion von kupfer und eisen sowie gallium mit isomeren langkettigen alkylchinolin-8-olenComplex formation and liquid-liquid extraction of copper,iron and gallium with isomeric long-chain alkylquinolin-8-ols

The extraction of copper(II) and iron(III) with the 5-nonyl-, 5- and 7-decyl- and 5-chloro-7-decyl derivatives of quinolin-8-ol was studied with chloroform, benzene or toluene as the organic solvent. Isomeric extractants show only small differences and are very suitable for the extraction of copper and its separation from iron, similarly to Kelex 100 (7-dodecenylquinolin-8-ol). With these derivatives log K_ex values are ?5.18 to ?6.08 for iron(III) with pH_0,5 = 4.5 to 5, whereas log K_ex values are 1.54 to 1.82 for copper(II) with pH_0,5 ≈ 1.35. The chelates of copper, iron and gallium with isomeric ligands, isolated as the solids, have characteristic differences in melting points and solubilities. To extract gallium from alkalin solution, only 7-alkyl-8-quinolinols proved as favourable.     

Neue Redoxserien auf der Basis von Übergangsmetallkomplexen heterocyclischer Arensulfonylhydrazone

New Redox Series Based on Transition Metal Complexes of Heterocyclic Arenesulfonylhydrazones Heterocyclic bidentate arenesulfonylhydrazones (2-acetylpyridine-p-toluenesulfonylhydrazone ? APSH? H, 2-acetylquinoline-p-toluenesulfonylhydrazone ? ACSH? H) with transition metal ions afford tetrahedral 1,2-complexes M^II(APSH)₂ and M^II(ACSH)₂. In most cases the E-isomers of APSH^? and ACSH^? are coordinated, five-membered chelate rings are formed with the pyridine and hydrazone nitrogen atoms as donor atoms. In the complexes Zn(APSH)₂ and Cu(APSH)₂ probably the Z-isomer of APSH^? is present with the pyridine and the sulfonylamide nitrogen atoms as a donor set, yielding a six-membered chelate ring. These proposals are based on the magnetic moments, the ligand field spectra, and the binding energies (ESCA). Normally the complexes M^II(APSH)₂ and M^II(ACSH)₂ are reduced in two reversible steps. For Fe(APSH)₂ and Fe(ACSH)₂ a third anodic wave, but for Cu(APSH)₂ only one wave is observed. Relations between redox properties and structure of the new complexes are discussed, and the redox series are compared with that of the M(dipy)₃ⁿ⁺-type complexes.     

Extraction of mercury(II) ions with antipyrine and its derivatives from chloride solutions to chloroform

The extraction of 0.01 mol/L mercury(II) ions from chloride solutions to chloroform is studied in the presence of antipyrine (AP) and its condensed derivatives (diantipyrylmethane (DAM), propyldiantipyrylmethane (PDAM), and hexyldiantipyrylmethane (HDAM)). The optimal mercury extraction conditions are determined for AP and its derivatives. The composition of the extracted complexes is determined. With respect to their pH_1/2 and extraction capacities, the extractants are arranged in the following order: AP < DAM < PDAM < HDAM. The calculation of partial equilibrium constants and approximate partition constants is proposed.     

Extraction of copper(II) ions from ammonia solutions with a β-diketone extractant

The extraction of copper(II) ions from ammonia solutions with a new β-diketone extractant, DX-510A, has been studied. Kinetic features of the copper(II) extraction and back extraction have been established: the reaction orders have been determined, and extraction and stripping rate constants have been calculated to be k_e1 = 4.14 × 10^–2 s^–1 and k_be1 = 3.20 × 10^–2 s^–1, respectively. It has been demonstrated that the extraction of copper(II) ions is not accompanied by the coextraction of ammonia. The type of extracted complex has been determined and its formula has been suggested.     

The role of the solvent in equilibrium and kinetic aspects of metal chelate extractions

Equilibria and kinetics for the extraction of nickel(II) and copper(II) by 2-hydroxy-5-nonylbenzophenone oxime (LIX 65N) in seven organic solvent systems were studied in order to test the validity of several hypotheses related to the role of the solvent in equilibrium and kinetic aspects of metal chelate extraction. For the nickel—LIX 65N system, the extraction constant is essentially independent of the solvent system, whereas for the copper—LIX 65N system, the extraction constant is not independent of solvent; this indicates that while the stoichiometry of the nickel chelate remains the same in all solvents, that of copper does not. The observed rate constant for the nickel—LIX 65N extraction was found to vary inversely with the LIX 65N distribution constant as predicted from a mechanism involving slow formation of the 1:1 complex. The observed reaction rate constant for the copper—LIX 65N varied inversely with the square of the distribution constant, also in accordance with the previously postulated mechanism of the slow formation of the 2:1 copper complex. This study, therefore, unequivocally eliminates the interfacial mechanism in favor of the homogeneous chemical reaction mechanism for the extraction of metal ions by LIX 65N, as well as by other similar high-molecular-weight extractants.     

Zum Einfluß von Benzylsubstituenten auf Basizität und Komplexbildungsvermögen von Aminocarbonsäuren – Kupferextraktion mit N,N-Dibenzylglycin

The Influence of Benzylsubstituents on the Basicity and the Coordination Behavior of Amino Acids – Copper(II) Extraction by N,N-Dibenzyl-glycine In amino acids the benzyl group is a strongly electron withdrawing ligand. This is demonstrated both by the pk_a values of N,N-dibenzyl-glycine ( II ), N-benzylalanine ( III ), and N,N′-dibenzylethylenediamine-N,N′-diacetic acid ( IV ) and by the stability of the corresponding transition metal complexes. Thus, compared to N,N-diethyl-glycine or N-methyl-alanine the pk_a values of II and III are lowered by 2.5 or 1.2 units. On account of the low pk_a2 value, in aqueous solutions of IV a bonding of the first proton to a nitrogen atom, but that of the second one to a carboxylate group is discussed. The transition metal complexes of II and III are considerably more instable than that of N,N-diethyl-glycine or N-methyl-alanine. With the anion of II , both in solution and in the solid state, the formation of copper(II) chelates, but not of the corresponding nickel(II) and cobalt(II) compounds was proved. Because of the solubility of II and its copper(II) chelate in chloroform, this amino acid may be used as a copper extractant (pH_1/2 = 3.5).     

Zum Verhalten von Cobalt(II) und Eisen(III) bei der Flüssig-Flüssig-Extraktion mit pyridylsubstituierten Benzensulfonamiden

On the Behaviour of Cobalt(II) and Iron(III) in Case of Liquid-liquid Extraction by Pyridyl Substituted Benzene Sulfonamides Pyridyl substituted benzene sulfonamides N 3 NHSO₂R and N 2 NHSO₂R which may be used as models of sulfonamide based metal extractants (LIX 34 et. al.) were studied as to their coordinative behaviour towards cobalt(II) and iron(III). The structure of Co(N 3 NSO₂R)₂ is distorted tetrahedral. Considering bond lengths and angles π-backdonation between cobalt and the nitrogen atoms is indicated which creates a higher effective charge on the central atom than in normal cobalt(II) complexes. Therefore, when observing normal conditions, Co(N 3 NSO₂R)₂ is not oxidized but reduced. Co(N 2 NSO₂R)₂ is a sulfonamide bridged tetramer with pentacoordinate cobalt(II). Iron(III) forms the low-spin complex salts [Fe(N 3 NHSO₂R)₂ (N 3 NSO₂R)](NO₃)₂ · xH₂O and [Fe(N 2 NHSO₂R)₂(N 2 NSO₂R)](NO₃)₂ · xH₂O which are insoluble in organic solvents. This is the reason why the copper(II)-iron(III) separation by sulfonamide based metal extractants proceeds without problems.     

Extraction and complexation of Cu(II) with undecanoic acid <Emphasis Type="Italic">N,N</Emphasis>-diethylhydrazide

A new reagent, undecanoic acid N,N-diethylhydrazide, was synthesized, and its pK _a1 was determined. The reagent recovers Cu(II) to 99–100% from solutions whose acidity ranges from pH 6 to 1 M NH₃. Copper(II) is extracted in the form of a neutral complex of the composition Cu(II):reagent = 1:2. The reagent is incorporated in the complex in the deprotonated form. An equation for the extraction of Cu(II) from ammonia solutions was suggested. The extraction isotherm was constructred. Ammonium salts, when present in solution, considerably decrease the degree of copper extraction. The reagent is less efficient extractant of copper than N,N-diethylbenzhydrazide.     

Spectroscopic and Electrochemical Studies of Transition Metal Complexes with N,N′-Bis(2-aminothiophenol)-1,7-bis(2-formylphenyl)-1,4,7-trioxaheptane and Structure Effects on Extractability of Ligand towards some Divalent Cations

Summary. La(III), Cu(II), Ni(II), and Zn(II) metal complexes with a novel quadridentate Schiff base derived from 1,7-bis(2-formylphenyl)-1,4,7-trioxaheptane and 2-aminothiophenol were synthesized and characterized by microanalytical data, elemental analysis, magnetic measurements, ¹H NMR, ¹³C NMR, UV-Vis, IR, mass spectra, cyclic voltammetric and conductance measurements. The extractability of divalent cations was evaluated as a function of relationship between distribution ratio of the metal and pH or ligand concentration. The highest extraction percentage of Cu²⁺ and Ni²⁺ showed pH 7.0 and 6.4. It was concluded that the ligand can effectively be used in solvent extraction of copper(II) and nickel(II) from the aqueous phase to the organic phase.     

Influence of Alkyl Chain Length and Structure on the Extraction of Copper(II) from Aqueous Acid by 5-Alkyl-2-hydroxybenzaldoximes in Hydrocarbon Solvents: Diffusion Coefficients of Extractants and Their Complexes

Measurement of the kinetics of extraction of copper(II) by 19 different 5-alkyl-2-hydroxybenzaldoximes (alkyl is C7H15 and C9H19) from acidic (hydrogen sulfate buffer) aqueous solution in the range pH 3.4-2.0, into 20% v/v toluene in n-hexane is reported. The lowering of the interfacial tension has been measured in some cases. The solubility of the extractants in water has been measured spectrophotometrically. A modified Taylor-Aris dispersion technique has been used to measure the diffusion coefficients in n-hexane and Orfom SX7 of some of the extractants and of the copper(II) complexes which they form. At low initial bulk concentrations (<10 mol m-3) of the extractants, the rate of extraction is controlled by the rate of diffusion of the extractant from the bulk to the organic-aqueous interface. The diffusion coefficient is related to the steric bulk of the alkyl substituent. At higher initial bulk concentrations (200 mol m-3) of the extractants, when the interface is saturated, the rate of extraction is inversely related to the apparent steric bulk of the alkyl substituent. Copyright 1999 Academic Press.     

Performance Evaluation of Nickel Separation and Extraction Process from Simulated Spent Cr/Ni Electroplating Bath Solutions by ELM Process Using LIX63 and PC88A

The study was conducted to investigate synergistic extraction of nickel from simulated spent Cr–Ni electroplating bath solutions by emulsion liquid membrane (ELM) process using 5,8-diethyl-7-hydroxydodecan-6-one oxime (LIX 63) and 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester (PC88A) as carriers. The importance of ELM composition and the properties of simulated spent electroplating bath solution have been optimized to synergistically extract nickel. The important parameters affecting the nickel extraction efficiency and ELM stability, such as acid concentration, stripping solution type and concentration, extractant concentration, surfactant concentration, and phase ratio, were experimentally studied. Along with obtained results, higher than 99% of nickel was selectively extracted within 30 minutes from simulated electroplating bath solutions that their metal concentrations was in the range of 100–500 mg/L. in the optimum conditions. The higher separation factor value of nickel over chromium (β_Ni/Cr) was obtained as 898. As a result, the nickel extraction kinetic was found to depend on PC88A, since extraction mechanism of PC88A is slower than that of LIX63. So, the combined use of LIX63 and PC88A improved the selective extraction of nickel in that process.     

Selective separation of copper with Lix 864 in a hollow fiber module

The transfer and separation of Cu(II), Co(II), Ni(II) and Zn(II) ions across a hollow fiber supported liquid membrane containing LIX 864 as the mobile carrier dissolved in kerosene solvent has been investigated. The flux and selectivity for copper has been studied as a function of the feed flow, the carrier concentration in the liquid membrane and the extraction solution acidity. A maximum copper recovery at 30% of LIX (v/v) in the diluent was obtained. The permeation experiments showed that at pH 2 in the extraction solution a highly selective separation of Cu over the other cations can be achieved. Increasing the acidity of the extraction solution copper selectivity decrease and the grade of recuperation sequence is Cu>Co>Ni>Zn. These results suggest that in selected situations, this membrane system can be competitive with the conventional liquid-liquid extraction process, in particular in leaching solutions with low metal concentration.     

A Study on the extraction of uranium(VI) from sulphate leach liquor using LIX63

The sulphate leach liquor obtained from the sulphuric acid leaching process of Egyptian monazite was treated using solvent extraction to recover U(VI) by LIX63. The influence of various basic variables such as pH, concentration of LIX63, temperature, different stripping agent, phase ratio and diluents was examined. Using 10% LIX63 with the aqueous solution at equilibrium pH 5.5 and a phase ratio A/O?=?1/1, a four-stage McCabe-Thiele plot was constructed, which showed 85.57% of U(VI) extraction. The thermodynamic data showed that the extraction process is exothermic with enthalpy change ΔH?=???43.866?kJ/mol, the stripping of U(VI) was quantitative using 4?M HNO₃. The stable complex UO₂(HSO₄)R_org formed during extraction which supports the cation exchange mechanism was confirmed by FTIR spectral analysis. Uranium cake was finally obtained from the strip solution by the addition of hydrogen peroxide and ammonium hydroxide as precipitating agents, and a workable flowsheet was then formulated.