The extraction of various metals as their anionic complexes with edta by solutions of aliquat-336 chloride in 1.2-dichloroethane

The extraction of anionic complexes of EDTA with Ca. Mg, V(IV), V(V), Cr(III), Mn(II), Mn(III), Fe(III), Co(II), Co(III), Ni, Cu(II), Zn, Cd, Hg(II), Pd(II), Pb and Bi by solutions of Aliquat-336 chloride in 1,2-dichloroethane has been studied as a function of the pH of the aqueous phase. The order and extent of the extractability varies greatly with the pH and provides a number of new possibilities for separation procedures. Thus iron(III) can be separated from many other metals in strongly alkaline solution while the extraction of V(V), V(IV), Hg(II) and Pd(II) exceeds 99% over wide pH ranges. The complex of Mn(III) with EDTA which is very unstable in aqueous solution can be preserved for up to 5 h when extracted by Aliquat-336.One of us (R. H. A1-J.) wishes to thank the Ministry of Oil of the Republic of Iraq for financial support.     

Chloroform extraction of ethyl xanthate complexes from sulphuric acid media

The chloroform extraction of 30 elements (Fe, Co, Ni, Zn, Cd, Ge, Sn, V, As, Sb, Bi, Cu, Ag, Au, Mn, Re, Ga, In, Tl, Se, Te, Cr, Mo, U, Pt, Pd, Rh, Ir, Ru and Ce) from 0.1-8M sulphuric acid in the presence of potassium ethyl xanthate has been studied. Pd(II), Bi, As(III), Sb(III), Se(IV) and Te(IV) are completely extracted and Au(III) is largely extracted over the range of acid concentration investigated. Fe(II), Tl(I), Rh(III) and Cr(VI) are only slightly extracted and Se(VI), Te(VI), Ru(III), Cr(III), Mn(II), Zn, Ce(IV), Ir(IV) and Ge(IV) are not extracted at all. Depending on the acid concentration, the remaining elements are all partly extracted. Results are compared with those obtained in an earlier study of the extraction of xanthate complexes from hydrochloric acid media. The processes involved in the formation of some xanthate complexes and potential analytical separations are discussed.     

Chloroform extraction of metal ethyl xanthates from hydrochloric acid media

The chloroform extraction of 32 elements (Fe, Co, Ni, Zn, Cd, Ge, Sn, Pb, V, As, Sb, Bi, Cu, Ag, Au, Mn, Re, Ga, In, Tl, Ce, Se, Te, Cr, Mo, U, Pt, Pd, Rh, Ir, Ru and Os) from O.1-10M hydrochloric acid media in the presence of potassium ethyl xanthate has been studied. The oxidation states in which some elements react, and potential analytical separations, are discussed. Pd(II), As(III) and Se(IV) are completely extracted as ethyl xanthate complexes, Te(IV) is almost completely extracted, and Au(III) is largely extracted over the range of acid concentration investigated. Mn(II), Zn, Rh(III), Ir(IV), Ru(III), Os(IV), Cr(III), Cr(VI), Ce(III) and Ce(IV) are not extracted. Ge is partly extracted from 6-10M media as the chloro-complex. Depending on the acid concentration, the remaining elements are all partially extracted as xanthate complexes.     

Development of liquid-liquid extraction and separation method for ruthenium(III) with 2-octylaminopyridine from succinate media: Analysis of catalysts

Ruthenium(III) has been efficiently extracted from 0.05 M sodium succinate at pH 9.5 by 2-octylaminopyridine in xylene and stripped with aqueous 10% (w/v) thiourea solution and determined spectrophotometrically. Various parameters viz., pH, weak acid concentration, reagent concentration, stripping agents, contact time, loading capacity, aq.: org. volume ratio, solvent has been thoroughly investigated for quantitative extraction of ruthenium(III). The utility of method was analyzed by separating the ruthenium(III) from binary mixture along with the base metals like Cu(II), Ag(I), Fe(II), Co(II), Bi(III), Zn(II), Ni(II), Se(IV), Te(IV), Al(III) and Hg(II) as well as platinum group metals (PGMs). Ruthenium(III) was also separated from ternary mixtures like Os(VIII), Pd(II); Pd(II), Pt(IV); Pd(II), Au(III); Pd(II), Cu(II); Fe(II), Cu(II); Ni(II), Cu(II); Co(II), Ni(II); Se(IV), Te(IV); Rh(III), Pd(II); Fe(III), Os(VIII). The stoichiometry 1: 2: 1 (metal: succinate: extractant) of the proposed complex was determined by slope analysis method by plotting graph of logD _[Ru(III)] versus logC _[2-OAP] and logD _[Ru(III)] versus logC _[succinate]. The interference of various cations and anions has been studied in detail and the statistical evaluations of the experimental results are reported. The method was successfully applied for the analysis of ruthenium in various catalysts, synthetic mixtures corresponding to the composition of alloys and minerals.     

Determination of Nb(V), V(V), Co(II), Fe(III), Ni(II), Ru(III) and Pd(II) as their 4-(5-nitro-2-pyridylazo) resorcinol chelates by reversed-phase high performance liquid chromatography

This paper reports the separation and determination of Nb(V), V(V), Co(II), Fe(III), Ni(II), Ru(III) and Pd(II) by reversed-phase HPLC using the new reagent, 4-(5-nitro-2-pyridylazo) resorcinol (5-NO₂-PAR) as a precolumn derivatization reagent. On a C₁₈ column, the seven metal chelates can be separated quantitatively with methanol/water (5248, v/v) containing 15 mmol/l pH 5.0 acetate buffer and 10 mmol/l tetrabutylammonium bromide (TBA·Br). The detection limits for Nb(V), V(V), Co(II), Fe(III), Ni(II), Ru(III) and Pd(II) are 0.65 ppb, 0.94 ppb, 0.10 ppb, 0.15 ppb, 0.18 ppb, 3.02 ppb and 2.35 ppb, respectively when the ratio of signal to noise (S/N) is 3. This method is simple and rapid, and has been used in the analysis of rain and liquor with satisfactory results.     

Extraction of Fe(III), Cu(II), Co(II), Ni(II) and Pb(II) with thenoyltrifluoroacetone using the ternary solvent system water/ethanol/methylisobutylketone

Single-phase solutions (1.72 x 10(-2)M in TTA) of water/ethanol/MIBK, when added to an excess of water, break down into two immiscible liquid layers and TTA complexes of Fe(III), Co(II), Ni(II), Cu(II) and PB(II) are extracted into the organic layer. Quantitative extractions were obtained for the five metals and separations of Fe(III) from a 1000-fold excess of Co(II), NI(II) or PB(II) are obtained. The reactions of the metal ions with TTA were studied in the single-phase solutions before the extraction step, giving useful information as to their complexation behavior.     

Analytical possibilities of pyridine-2-acetaldehyde benzoylhydrazone as a chromogenic reagent

With a view to the use of pyridine-2-acetaldehyde benzoylhydrazone is an analytical reagent, a study of the physical properties and fundamental solution chemistry of the complexes formed by PABH with Fe(II), Fe(III), Ni(II), Pd(II), V(V), Ti(IV), Hg(II), Mn(II), Zn(II), Bi(III), Co(II), Cu(II), Pb(II), and Ga(III) metal ions has been carried out. A critical comparison of pyridine-2-carbaldehyde and pyridine-2-acetaldehyde salicyloylhydrazones and pyridine-2-acetaldehyde benzoylhydrazone as analytical reagents is given.     

Synthesis and spectral studies of transition metal complexes with 1,5:11,15-dimetheno-2,4,10,12-tetramethyl-[1,5,9,13]-tetraazahexadeca-1,3,5,6,10,11,13,15,16,20-decene a sixteen-membered tetradentate macrocyclic ligand

Complexes of Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Pd(II), Pt(II), Ru(III) and Ir(III) with a sixteen-membered 1,5:11,15-dimetheno-2,4,10,12-tetramethyl-[1,5,9,13]-tetraazahexadeca-1,3,5,6,10,11,13,15,16,20-decene macrocyclic ligand have been synthesized. These complexes are characterized by magnetic moment, infrared, electronic, EPR and mössbauer spectral studies. All of complexes were found to have six-coordinated octahedral geometry and are of the high spin type except for the Pd(II) and Pt(II) complexes which are four coordinate, square planar and diamagnetic.     

Spectrophotometric study of Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and Pb(II) complexes with some crown ethers in dimethylsulphoxide solution using murexide as a metallochromic indicator

The complexation reactions between Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and Pb(II) ions and benzo-15-crown-5, dicyclohexyl-18-crown-6, dibenzo-18-crown-6 and 1,10-diaza-18-crown-6 have been studied in dimethylsulphoxide solution at 25 degrees by means of a competitive spectrophotometric method using murexide as a metallochromic indicator. With the exception of Pb(II)(benzo-15-croqn-5)(2) the stoichiometry of the resulting complexes was found to be 1:1. The formation constants of the complexes were determined, and found to follow the Irving-Williams rule for the cations of the first transition series. It was found that the metal ion-18-crown interactions are strongly dependent on the nature of the substituents on the ring.     

Mononuclear and polynuclear chelates of picolinoyldithiocarbazate

Mononuclear and polynuclear chelates of potassium picolinoyldithiocarbazate (KHPcDC) with Mn(II), Fe(ll1), Fe(II), Co(Il), Ni(II), Cu(II), Zn(II), Cd(II), Hg(II), Pd(II) and U(VI)O2 have been prepared and characterized by chemical and thermal (TG, DTG, DTA) analyses, molar conductivities, spectral (UV-Visible, IR, NMR, ESR) and magnetic moment measurements. The molar conductivities of the complexes lie in the non-electrolyte range whilst KHPcDC is a 1:1 electrolyte. Changes in selected vibrational absorption of the ligand upon coordination indicate that KHPcDC behaves as monoanionic and coordinates in a bidentate, tridentate and/or bridging tetradentate manner. Trans-form structure is proposed for [Pd(HPcDC)2] x 2H20 and [Cd(HPcDC)2] complexes on the basis of NMR data. An octahedral structure is proposed for Fe(III), Fe(II) and Ni(II) complexes, a square-planar structure for Co(II) and Pd(II) complexes and a tetragonally distorted octahedral structure for the Cu(II) chelate on the basis of spectroscopic and magnetic data. The ligand field parameters (B, Dq, beta) for the Fe(III) and Ni(II) chelates were calculated. TG, DTG and DTA studies support the different modes of chelation of KHPcDC. The solid metal acetate chelates have a unique decomposition exotherm profile which can be used as a rapid and sensitive tool for the detection of acetate-containing complexes.     

Extraction of group VIII elements with 1-phenyl-3-methyl-4-trifluoroacetyl-pyrazolone-5

The extraction of group VIII elements with 1-phenyl-3-methyl-4-trifluoracetyl-pyrazolone-5 from aqueous solutions in chloroform has been studied as a function of pH. Fe(III), Ni(II), Pd(II) and Rh(III) show partial extraction whereas Co(II) is extracted quantitatively. The effect of citrate, cyanide, fluoride, iodide, thiosulphate and thiourea on the extraction of metal ions has been investigated. Back-extraction studies were carried out to strip metal ions from organic phase into appropriate aqueous solutions. Based on these findings some useful analytical separations have been proposed and a few of their possible applications have been discussed.     

Inorganic polarography in organic solvents-I Some metal-pyridine-thiocyanate complexes in toluene

Results are reported for the direct application of polarography to the examination of organic phases following solvent extraction. Experimental factors such as suitable solvents, supporting electrolytes and electrode parameters have been studied and the method is tested for the extraction of the Cd, Co(II), Cu(II), Fe(II), Mn(II), Ni and Zn pyridine/thiocyanate complexes into toluene. The results show that the sensitivity is increased by the concentrating effect of the extraction system and better selectivity is achieved without searching for a suitable supporting electrolyte.     

Determination of gold by substoichiometric extraction with N-thioacetyl benzamide

Estimation of gold has been successfully carried out by substoichiometric radiochemical solvent extraction method using a newly designed organic moiety, N-thioacetyl benzamide as extractant and chloroform as solvent at aqueous pH 4. The interference effects of different closely related diverse ions like Fe(III), Cu(II), Co(II), Zn(II), Ni(II) etc. were also critically studied. The validity of this method has been verified by the study of recovery of gold in mud samples.     

Organic acid solutions in the chromatography of inorganic ions VIII. Cation-exchange of Mn(II), Cd(II), Co(II), Ni(II), Zn(II), Cu(II), Fe(III), Sc(III), Y(III), Eu(III), Dy(III), Ho(III), Yb(III), Ti(IV) and Nb(V) in malate media

Summary The cation-exchange behaviour of Mn(II), Cd(II), Co(II), Ni(II), Zn(II), Cu(II), Fe(III), Sc(III), Y(III), Eu(III), Dy(III), Ho(III), Yb(III), Ti(IV) and Nb(V) in malate media at various concentrations and pH, was studied with Dowex 50 WX8 resin (200–400 mesh) in the ammonium form. Separation of Fe(III)/Cu(II), Fe(III)/Cu(II)/Zn(II), Fe(III)/Co(II)/Mn(II), Cu(II)/Ni(II)/Mn(II), Fe(III)/Cu(II)/Co(II)/Mn(II), Fe(III)/Cu(II)/Ni(II)/Cd(II), Yb(III)/Eu(III), Sc(III)/Y(III),Sc(III)/Yb(III)/Dy(III) and Nb(V)/Yb(III)/Ho(III) has been achieved, among others.This work was supported by C.N.R. of Italy.     

Extraction of copper(II) with 1,2-diacylhydrazines in the presence of associated metals

Conditions of Cu(II), Zn(II), Ni(II), Co(II), and Fe(III) ions extraction (pH values, effect of reagent amount) with symmetrical 1,2-diacylhydrazines derived from straight-chain aliphatic carboxylic acids and α-branched higher carboxylic acids Versatic-10 were studied. The separation coefficients of element pairs and pH of half extraction were calculated. The values of [Cu(II)]: [reagent] ratios in extracted complexes were determined. 1,2-Diacylhydrazines were shown to be more selective extractants toward nonferrous metal ions as compared with carboxylic acids, while the branching and elongation of alkyl chain in the reagents enhances their extraction properties and compatibility with hydrocarbon solvents.     

Extractive concentration of platinum-group elements and their determination by atomic-absorption spectrophotometry

The extraction of Pt, Pd, Ir, Rh, Ru, Ag, Au, Co, Cu, Ni and Fe with n-octylaniline has been investigated. Noble metals are extracted 10(3)-10(4) times better than Cu, Ni, Co and Fe. A method of determination of Pt, Pd, Ir, Rh and Ru is proposed. They are first separated from Cu, Ni, Co and Fe by means of extraction (and then determined, in either the aqueous or organic phase, by atomic-absorption spectrophotometry. The atomic absorption of platinum metals (with the exception of Pd) is affected by other elements of the platinum group and by non-noble metals. La(NO(3))(3) and Nd(NO(3))(3) lower the limit of detection for Pt, Rh, Ir and Ru and inhibit the effect of Co, Cu, Ni, Fe, Bi, Zn, Na, etc. on their determination. Lanthanum and neodymium chlorides and sulphates produce a similar effect but only on the determination of Pt and Rh. The coefficient of variation of the determination, in both phases, is within 2-6.8%.     

Alpha-benzoinomixe: Extracting agent for uranium(VI), tungsten(VI), molybdenum(VI) and some transition metals of the iron family

The effect of pH on the percent extraction of vanadium(V), iron(II), cobalt(II), nickel(II), copper(II), molybdenum(VI), tungsten(VI) and uranium(VI) by -benzoinoxime in different solvents has been studied. The maximum recovery is not appreciably affected by the nature of the solvent, but occurs at different pH values for different metals. The pH corresponding to maximum extraction increases with increasing hydrolysis pK of the species in aqueous solution, and decreases with increasing stability constant of the complexes formed. Alpha-benzoinoxime allows the separation of these metal ions into three groups: V(V), Mo(VI) and W(VI) are extracted at pH=2, U(VI) at pH=5, Fe(II), Cu(II), Co(II) and Ni(II) at around pH=10.     

Schiff-Basen aus 1,3-Dicarbonylverbindungen und Triaminen und ihre Fe (III)-, Co (III)-, Ni(II)- und Cu(II)-Komplexe

Schiff bases of 1,3-dicarbonyl compounds with triamines and their Fe(III), Co(III), Ni(II) and Cu(II) complexes The preparation of new hexadentate ligands obtained by the reaction of cis, cis-1,3,5-triaminocyclohexane (tach) or 1,1,1-tris (aminomethyl)ethane (tame) with an 2-ethoxymethylidene-1,3-dicarbonyl compound as well as their Fe(III), Co(III), Ni(II) and Cu(II) complexes is reported. Fe(III) and Co(III) yield neutral complexes with an octahedral N₃O₃-coordination sphere, Ni(II) and Cu(II) complexes with a square-planar coordination-sphere. In the later complexes one of the bidentate branches of the ligand is not deprotonated and stays uncoordinated.     

the extraction of some metallic bromides from aqueous solutions with methyl ethyl ketone and methyl iso-butyl ketone

The extraction of the following metals from aqueous solutions containing excess bromide with methyl ethyl ketone (MEK), and methyl isobutyl ketone MIBK has been investigated:—Cu(I), Cu(II), Zn(II), Ni(II), Co(II), Fe(II), Fe(III), Al(III), Mn(II), Sn(II) and Sn(IV). The use of MEK was found to be strictly limited by its solubility in acidic aqueous solutions. Determinations of the formulae of the extracted compounds were attempted in two cases but were found to be not wholly satisfactory and were discontinued. An interesting reaction between the cupric bromide complex and the solvents was noticed. Separations of Fe(IIl) from Mn(II), Fe(III) from Al(III), Fe(III) from Co(Il) and Fe(III) from Ni(II) could be achieved under suitable conditions.     

Simultaneous determination of metal ions. Catalytic oxidation of cobalt by metal ions when extracted with quinolin-8-ol

The catalytic effect of various ions on the aerial oxidation of Co(II) when extracted from weakly acidic solutions with quinolin-8-ol in chlorofom was studied. Oxidation is complete only in the presence of Fe(III) or V(V). Mixtures of Al(III), Cu(II), Fe(III) and Ni(II) with Co(II) at concentrations in the range 1–8 μg ml^?1 were analysed by using a multi-component analysis program involving first-order derivative spectra. Because of the metal ion interaction, a multivariate calibration process is required. The recovery factors achieved ranged from 93 to 111%.