Investigation of the use of diphenyl-2-pyridylmethane in benzene as an extractant for palladium from aqueous thiocyanate-nitrate solutions

The extraction of palladium/II/ with diphenyl-2-pyridylmethane /DPPM/ in benzene has been investigated from thiocyanate-nitrate media and optimized. Thiosulphate ions showed strong interference and reduced the extraction below 1%. Separation factors determined for most of the elements were better than 10³. This extraction method affords palladium preconcentration and its separation from Sc/III/, Co/II/, Cu/II/, Zn/II/, Se/IV/, Sr/II/, Ru/III/, Cd/II/, Cs/I/ and Eu/III/. Few possible applications of such separations have been cited.     

Speciation of Pu ions by differential pulse polarography

By means of differential pulse polarography, Pu ions of different oxidation states have been investigated in 1M Na₂CO₃ solution. Redox reactions of Pu/III/, Pu/IV/, Pu/V/ and Pu/VI/, which are mostly of irreversible nature, have been observed within the potential range of the dropping mercury electrode /DME/, from 0 to –1.5 V, against a Ag/AgCl/NaCl (3M) reference electrode. Based on the peak potential observed for each reaction, the stability of a given oxidation state in the solution could be ascertained. The redox potential of the Pu/IV/–Pu/III/ pair, which was found to be –1.0 V, indicated that the Pu/IV/ carbonate complex was of high stability. The detection sensitivity of the Pu/IV/ ion was found to be 1×10^–6M.     

Solvent extraction separation of In/III/-Tl/III/ and Hg/II/-Cd/II/-Co/II/ with sulphoxides

Solvent extraction studies have been made on some metals: In/III/-Tl/III/ and Hg/II/-Cd/II/-Co/II/, from ammonium thiocyanate solutions by dialkyl sulphoxides. Separation of these metals from one another can be achieved by suitable choice of the extracted conditions. The nature of the extractable metal species has been elucidated.     

Tri-n-octylphosphine sulfide: : A selective organic extractant

Tri-n-octylphosphine sulfide (TOPS) has been investigated as the stationary phase in reversed-phase partition paper Chromatographie separations using nitric or hydrochloric acids as the mobile phase. TOPS has also been studied as an extractant for metal ions. Silver, mercury (II), and palladium (II) were found to have RF values of zero when nitric acid was used as the mobile phase. These same ions were also selectively extracted from aqueous nitric acid solutions. Gold(III), mercury(II), palladium (II), and platinum (IV) were found to have RF values of zero when hydrochloric acid was used as the mobile phase. However, only gold(III) and mercury(II) were extracted from aqueous hydrochloric acid solutions in liquid-liquid extraction systems. Several separations were successfully performed from 1 M nitric acid.     

Radiation decomposition of metal acetyl acetonates

Studies on the thermal decomposition of the acetyl acetonate complexes of transitional metal ions Cu/II/, Cr/III/, Mn/II/, Co/II/, Fe/III/, Vo/II/, Zn/II/, and Cd/II/ have been performed by thermogravimetric method. Taking the initial decomposition temperature as a measure of thermal stability, the relative order of the thermal stability of these complexes shows the following order: Zn/II/<Cd/II/< VO/II/<Fe/III/<Cr/III/<Cu/II/Co/II/< Mn/II/. The nature of decomposition of Cu/II/ and Cr/III/ complexes is similar, a sigmoid curve exists. In other cases a long linear decomposition follows the sigmoid pattern. The linear decomposition is a function of final decomposition temperature and percentage of decomposition. The kinetics of the decomposition is analyzed according to the Coats-Redfern equation. The results are discussed on the basis of structural and other aspects leading to the decomposition.     

Extraction of Th,Pa, U,and Np by PMBP from aqueous solutions at short phase contact times

The extraction properties of Th/IV/, Pa/V/, U/VI/ and Np from nitric acid solutions into 1-phenyl-3-methyl-4-benzoylpyrazolone-5 /PMBP/ in toluene were studied, using singlestep batch and continuous H-centrifuge methods. The effects of acid and extractant concentration, temperature and phase contact time on the extraction were 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.     

Catalytic method for determination of micro amounts of gold in iron ores

Summary Gold in iron ores has been determined by means of its catalytic action on the oxidation of mercury(I) by cerium(IV). The calibration curve is linear over the range 3–30 ng/ml. Only iridium(IV), platinum(IV), palladium(II), ruthenium(III) and gallium(III) interfere seriously, though some interference is experienced from lead(II), iron(III), osmium(VIII) and indium(III).

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Zusammenfassung Gold wurde in Eisenerzen auf Grund seiner katalytischen Wirkung auf die Oxydation von Quecksilber(II) durch Cer(IV) bestimmt. Die Eichkurve verläuft von 2 bis 30 ng/ml linear. Nur Iridium(IV), Platin(IV), Palladium(II), Ruthenium(III) und Gallium(III) stören ernstlich, während eine geringfügige Störung auch durch Blei(II), Eisen(III), Osmium(VIII) und Indium(III) beobachtet wurde.

     

Extraction of U/VI/ and U/IV/ with some 1-phenyl-3-methyl-4-acylated-pyrazolone-5 compounds

A series of novel chelating reagents 1-phenyl-3-Methyl-4-p-Nitro-Benzoyl-Pyrazolone-5 /PMNBP/, 1-Phenyl-3-Methyl-4-o-Chlor-Benzoyl-Pyrazolone-5 /PMCBP/, 1-Phenyl-3-Methyl-4-Acyl-Pyrazolone-5 /PMAP/ have been synthesized. The extraction of U/VI/ and U/IV/ from hydrochloric acid in chloroform with these reagents as well as 1-Phenyl-3-Methyl-4-Benzoyl-Pyrazolone-5 /PMBP/ has been studied. The influence of the concentration of the reagents in organic phase, on the distrubtion ratio /D/, has been measured. The coordination of the compounds has been determined with the slope method, and the equilibrium constants k_ex, were measured.     

The stability constants of some metal chelates of triethylenetetraminehexaacetic acid (ttha)

Stability constants for Al(III), Cd(II), Co(II), Cu(II), Fe(III), Hg(II), La(III), Nd(III), Er(III), Mg(II). Mn(II), Ni(II), Pb(II), Th(IV) and Zn(II) complexes of triethylenetetraminehexaacetic acid (TTHA) have been evaluated from data obtained by pH and pM measurements. The pM method based on measurements with the mercury electrode and the redox system Fe(III)/Fe(II) proved to be very useful when binuclear complexes are formed.     

Preconcentration and separation of iron, zinc, cadmium and mercury, from waste water using Nile blue a grafted polyurethane foam

The present work describes a novel method for the incorporation of Nile blue A into polyurethane foam matrix. This foam material was found to be very suitable for the extraction of metal ions from aqueous solutions. The characterization of Nile blue A grafted foam and the effect of halide concentration, pH, shaking time, extraction isotherm and capacity have been investigated. This foam material was found to be suitable for the separation and preconcentration of iron (III), zinc (II), cadmium (II) and mercury (II) from waste water. The extraction was accomplished in (15-20) minutes. Iron was separated from acid medium (2-4 M HCl), zinc from (3-5 M HCl), cadmium from (4-6 M HCl) as thiocyanate complexes and mercury was separated from (1-2 M HCl) as chloride.     

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.     

Metal complexes of isonicotinic acid hydrazide

Complexes of platinum(IV), ruthenium(III), rhodium(III), iridium(III), gold(III), dioxouranium(II), zinc(II), cadmium(II), mercury(II) and manganese(II) with isonicotinic acid hydrazide were prepared and characterized on the basis of analytical, conductometric, magnetic susceptibility and spectral data. Platinum(IV) ruthenium(III), rhodium(III), iridium(III), dioxouranium(II) and manganese(II) form six-coordinate complexes while gold(III), zinc(II), cadmium(II) and mercury(II) form four coordinate complexes.     

Extraction of actinides and fission products by octyl(phenyl)-N,N-diisobutylcarbamoylmethyl-phosphine oxide from nitric acid media

Extraction of promethium(III), uranium(VI), plutonium(IV), americium(III), zirconium(IV), ruthenium(III), iron(III) and palladium(II) has been carried out with a mixture of octyl(phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide (CMPO) and tributyl phosphate (TBP) in dodecane. The effects of nitric acid, TBP and CMPO concentrations on the extraction of these metal ions have been studied. The nature of the species of the above metal ions extracted into the organic phase has been suggested.     

Disodium-1,8-dihydroxy-naphthalene-3,6-disulphonate (chromotropic salt) as a reagent in inorganic analysis

Summary The compound disodium-1,8-dihydroxy-naphthalene-3,6-disulphonate (sodium salt of chromotropic acid) is employed as a colorimetric reagent for titanium. It is also known to produce coloured complexes with chromium(VI), vanadium and uranium. In the present paper the formation of colour with forty metallic ions has been studied qualitatively, in neutral as well as in alkaline and acidic media. It has been found that the reagent yields coloured complexes with mercury(I), tin(IV), platinum(IV), gold(III), tellurium(VI), molybdenum(VI), iron(III), aluminium(III), chromium(III), and uranyl(II) besides those recorded above.The colour reactions are particularly sensitive to uranyl(II), iron(III), mercury(I), tin(IV), gold(III) und molybdenum(VI).     

Separation of gold from Cu, Pt, Pd, Ni, Zn, Cd and Hg using triphenylarsine oxide as an extractant

A method is developed for extraction of gold(III) (75–300 g) from hydrochloric acid solution with triphenylarsine oxide dissolved in toluene as extradant. Gold(III) is determined spectrophotometrically with stannous chloride. The extraction is quantitative from 1.5–1.9M hydrochloric acid with 0.25% triphenylarsine oxide and an equilibration period of 30s. The method permits separation of gold(III) from Cu(II), Pt(IV), Pd(II), Ni(II), Zn(II), Cd(II) and Hg(II) and its spectrophotometric determination in ayurvedic medicines. The recovery and relative standard deviation obtained are >99.0% and <1.0%.     

Promoting effect of iodide on the hexacyanomanganate(IV)-arsenic(III) redox reaction, for kinetic determination of iodide

The rate of the reaction between hexacyanomanganate(IV) and arsenic(III) in an acid medium is strongly accelerated by iodide. The reaction kinetics indicates that the iodide activity decreases throughout the reaction, probably because manganese(IV) oxidizes iodide to iodate (an inactive form). This behaviour is defined as promotion, rather than catalysis, and this rate-modifying effect has been used to determine iodide by a kinetic method. A linear calibration plot was obtained by a two-point fixed-time procedure. A detection limit of 0.2 ng/ml, a quantification limit of 0.6 ng/ml and relative standard deviations of 5.5 and 13% for the 6.7 and 0.6 ng/ml levels respectively have been found. Positive kinetic interferences from osmium(VIII) and iodate have been observed, and copper(II), silver(I) and mercury(II) inhibit the iodide activity by precipitaton. The method has been applied to determination of iodide in sodium arsenite (reagent grade) and table salt. The method has been validated by recovery experiments.     

Metal chelate exchange in the organic phase-II Extraction and exchange constants of dithizonates and diethyldithiocarbamates

Dithizonates and diethyldithiocarbamates of Ag, Tl(I), Cu(II), Zn, Cd, Hg(II), Pb, Fe(II), Co(II), Ni, Pd(II), In(III), As(III), Sb(III), Bi, Se(IV) and Te(IV) have been prepared and their reactions in carbon tetrachloride have been studied spectrophotometrically. From the exchange constants determined, the extraction constants of metal diethyldithiocarbamates have been calculated. Where formation of mixed chelates has been observed, corresponding exchange constants have been determined. Finally, the influence of organic solvents (CCl(4), CHCl(3), C(6)H(6) and C(6)H(5)Cl) on the exchange reaction of zinc diethyldithiocarbamate with dithizone has been investigated.     

TRENDS IN THE OPTICAL ROTATORY DISPERSION SPECTRA OF R-(−)-1,2-PROPYLENEDIAMINETETRAACETATO COMPLEXES OF GROUPS IIA,IIB,IIIA,IIIB,IVB AND SOME HEAVY METALS

Abstract

A general periodic trend was observed in the optical rotatory dispersion spectra of the R-(?)-1,2-propylenediamine-tetraacetato (R(?)PDTA) complexes of Group IIA metals: magnesium(II), calcium(II), strontium(II), and barium(II); Group IIIB metals: scandium(III), yttrium(III), and lanthanum(III); Group IVB metals: titanium(IV), zirconium(IV), and thorium(IV); Group IIB metals: zinc(II), cadmium(II), and mercury(II); Group IIIA metals: aluminum(III), indium(III), and thallium(III); and the heavy metals: mercury(II), thallium(III), lead(II), and bismuth(III). The periodic trend was related to the ionic potential of the metals within each group, in that as the ionic potential increases within a group, the molecular rotations decrease from a positive to a negative value at any given wavelength outside of a region of anomalous optical rotatory dispersion. Comparing the heavy metal, mercury(II), lead(II), thallium(III), and bismuth(III), complexes of R(?)PDTA, outside of the region of anomalous rotatory dispersion, the metal with the same charge but smaller ionic potential has the greater positive molecular rotation at any given wavelength.     

Studies on the liquid-liquid extraction of iron(III) and titanium(IV) with 3-phenyl-4-benzoyl-5-isoxazolone

The extraction behaviour of iron(III) and titanium(IV) from acidic chloride solutions has been investigated using 3-phenyl-4-benzoyl-5-isoxazolone (HPBI) in xylene as an extractant. The results demonstrate that these metal ions are extracted into xylene as Fe(PBI)(3) and TiO(PBI)(2). The equilibrium constants of the extracted complexes have been deduced by non-linear regression analysis by taking into account complexation of metal ion with inorganic ligands in the aqueous phase and all plausible complexes extracted into the organic phase. IR and proton NMR ((1)H NMR) spectra were used to further clarify the nature of complexes extracted into organic phase. The effect of the nature of the diluent on the extraction of iron(III) and titanium(IV) has been studied and correlated with dielectric constants. The extraction behaviour of titanium(IV) has also been compared with that of other metal ions, viz. magnesium(II), vanadium(V), chromium(VI), iron(III), manganese(II), zinc(II) and zirconium(IV), which are associated with the titanium in waste chloride liquors of the titanium-mineral-processing industry.