Studies on the liquid-liquid extraction and ion and precipitate flotation of Co(II) with decanoic acid

The liquid-liquid extraction, ion and precipitate flotation of Co(II) from chloride media of 1·10^–4M initial Co(II) concentration and =0.1 have been investigated using decanoic acid and the results are compared. Organic solvents used were chloroform in the case of liquid-liquid extraction and ethanol (used as a solvent for the collector and a frother) in the case of flotation. From the results it appears that liquid-liquid extraction takes place through the formation of the complex: (CoR₂)₂(HR)₂ but flotation occurs through the formation of a surface active product which has the empirical formula CoR₂. The effects of pH and of decanoic acid concentration on the three separation processes were also investigated and the results discussed. Good agreement was observed between the experimental precipitate flotation curves and the theoretical curve calculated from the data published for Co(II) hydrolysis.     

Separation of Co(II) from dilute aqueous solutions by precipitate and adsorbing colloid flotation

Ion, precipitate and adsorbing colloid flotation of cobalt(II) have been investigated at different pH values, using N-dodecylpyridinium chloride (DPCl), A strong cationic surfactant, and sodium lauryl sulfate (NaLS), a strong anionic surfactant, as collectors. In case of adsorbing colloid flotation, hydrous manganese dioxide was used as an adsorbent. The precipitate flotation curves experimentally obtained with the two tested collectors were compared with the corresponding theoretical one calculated from the data published for Co(II) hydrolysis. The effects of the collector concentration, ageing of the water-MnO₂–Co(II) system, bubbling time period, cobalt(II) concentration and foreign salts on the percent removal of Co(II) by adsorbing colloid flotation using DPCl as collector were determined. Removals approaching 100% could be achieved under the optimum conditions.     

Kinetic studies on the foam separation of thorium (IV) with sodium lauryl sulphate

Summary The effects of pH, gas flow rate and collector concentration on the rate of thorium removal by foaming with sodium lauryl sulphate have been investigated. The obtained data indicate that only aged hydrated thorium oxide is removed by a flotation mechanism. All the other colloidal and condensed thorium species as well as the colloidal sublates which are formed between the dissolved thorium species and the collector anions appear to be removed by partition and their removal rates could be described by a reversible first-order rate equation. The obtained results are discussed in terms of thorium hydrolysis.

---

Zusammenfassung Der Einfluß der pH-Werte, Gasdurchflußmengen und Kollektor-Konzentration auf die Geschwindigkeit der Entfernung des Thoriums durch Schaumbildung mit Natrium-Lauryl-Sulfat wurde untersucht. Die Ergebnisse zeigen, daß das gealterte, wässerige Thoriumoxid durch Flotations-Mechanismen entfernt wird. Die anderen kolloidalen und kondensierten Thorium-Spezien und auch die Kolloidalprodukte, die durch Reaktionen zwischen den gelösten Thoriumspezien und den Kollektor-Anionen formiert sind, sind durch die Verteilung entfernt worden. Die Entfernungsgeschwindigkeit kann beschrieben werden durch eine reversible 1. Ordnungs-Gleichung. Die Ergebnisse werden in Abhängigkeit einer ThoriumHydrolyse diskutiert.

---

---

With 7 figures     

3,4-Dicyano-5-aminopyrazole complexes of anhydrous divalent transition metal chlorides and their triphenylphosphine derivatives

Summary 3,4-Dicyano-5-aminopyrazole, H3,4(CN)₂5NH₂pz (L) reacts either with anhydrous MCl₂ or with [M(PPh₃)₂Cl₂] to yield ML₄Cl₂ complexes (M = Cr, Mn, Fe, Co, Ni, Cu, Zn, Cd or Hg), whose monomeric and covalent natures have been confirmed by their solubility in most non-polar solvents and their low electrical conductivities. The bonding mode of substituted pyrazole is inferred from the position of the (C-N) band in the i.r. spectra. The electronic spectra and the magnetic moments of these compounds were recorded.     

Synthesis and characterization of adducts of dichlorosulphato bis(1,3-propylenediamine)metal(II) complexes with dialkyltin dichlorides

Summary Adducts of dichlorosulphato bis(1,3-propylenediamine)-metal(II) complexes with dialkyltin dichlorides, [R₂Sn(MeCN) ₂]₂[M(NH(CH₂)₃NH)₂(SO₃Cl)₂] (M = Cr, Fe, Co, Ni or Cu; R = Me or n-Bu) have been prepared. The positive shift in the symmetric SO₃ stretch and splitting of the doubly degenerate (E) modes in their i.r. spectra suggest a covalent linkage for the SO₃Cl^– group. The adducts are non-electrolytes; magnetic moments and ligand field data suggest that each SO₃Cl^– group is monodentate, generating an octahedral geometry around the metal ions, except for Ni^II where tetragonal distortion is observed.Author to whom all correspondence should be directed.     

Ethylenediamine complexes of transition metalbis(chlorosulphates)

Summary The number and positions of the i.r. active modes in ethylenediamine complexes of M(SO₃Cl)₂ (M = Mn, Fe, Co, Ni or Cu) suggest that the SO₃Cl^– anion is covalently bound in these non-electrolytic complexes. Magnetic moments and ligand field data suggest that each SO₃Cl^– group is monodentate, giving an octahedral geometry around the metal ions.     

Removal of Co(II) from dilute aqueous solutions by adsorption on charcoal and subsequent macroflotation of the sorbent

As a part of a research program on the treatment of radioactive process waste waters, sorbent macroflotation was tested to remove Co(II) from dilute aqueous solutions. Activated charcoal was used as the sorbent, and gelatin, cetylpyridinium chloride, dodecylamine or N-dodecylpyridinium chloride (NDPC) as the collector. In addition to the effect of the collector type on the percent removal, the effects of the pH, the charcoal and collector doses, the metal ion concentration, the ionic strength and the use of combinations of NDPC with other reagents have been investigated. At the optimum conditions removals better then 97% could be achieved in the pH range of 7.5–10.0 with NDPC plus a low concentration of a low-molecular-weight polyacrylamide. The results obtained are discussed in terms of hydrolysis of the metal ion and the electric state of both the charcoal and collector.     

Six-coordinate dinuclear hexaazamacrocyclic complexes of nickel(II), copper(II) and zinc(II) with tetraamide group ligands

Summary A series of 20–24 membered macrocyclic dinuclear transition metal complexes [M₂L¹X₄]-[M₂L⁴X₄] (M = Ni^II, Cu^II or Zn^II; X = Cl or NO₃) have been synthesized by template condensation of diethylenetriamine with dicarboxylic acids. The bonding and stereochemistry of the complexes have been characterized by i.r.,¹H-n.m.r., e.p.r. and electronic spectral studies, magnetic susceptibility and conductivity measurements. The Ni and Zn complexes exhibit octahedral geometry around the metal ion, whereas the Cu complexes possess a distorted octahedral geometry. Each metal ion is coordinated by two amide nitrogens and two secondary nitrogens of the diethylenetriamine moiety; the fifth and sixth coordination sites are occupied by the anions.     

Extraction of uranium(VI) with non-plasticized and TBP-plasticized polyurethane foam sorbents loaded with dibenzoylmethane

Studies have shown that plots of the log of the distribution ratio versus pH for the distribution of uranium(VI) between non-plasticized and TBP-plasticized dibenzoylmethane-loaded polyurethane foams and dilute aqueous uranium(VI) solutions have a limiting slope of 0.6 at equilibrium pH values 4 and reach a maximum distribution constant at about pH 6.0. The results indicate that the extracted complex is a simple chelate, UO₂Me₂, where HMe denotes dibenzoylmethane. Plasticization of the foam with TBP has been found to significantly enhance the rate of extraction.     

Absorption, fluorescence, and semiempirical ASED-MO studies on a typical Brooker''s merocyanine dye

Solvatochromism and Solvatofluorchromism of Brooker's merocyanine 1-methyl-4- (4′-hydroxystyryl) pyridinium betaine, M, were studied in twelve polar protic and aprotic solvents. Moderate hypsochromic fluorescence energy shifts are 4.57 kcal mole⁻¹ while strong hypsochromic absorption energy shifts are 16.63 kcal mole⁻¹. Decreasing of the dipole moment of M upon excitation is the factor, which is responsible for the difference between the two energy shifts. The change of both energies rectilinearly with solvent acidity scale shows the importance of oxygen atom of M as a strong basic center. The application of the atom superposition and electron delocalization molecular orbital (ASED-MO) theory reproduces geometrical and electronic structures for M, which agree well with the experimental observations. The calculations suggest strongly that the dye has a benzenoid valence structure in the ground state and shifts towards a quinonoid one upon excitation with an observed decreasing of the dipole moment. The changing of the dipole moment is explained clearly depending upon the calculated charge distribution over the whole skeleton of the molecule. The formation of a H-bond between the water molecule and the highly negative oxycyclic oxygen atom of M has slightly effect on its dipole moment in the ground state. This leads to suggest that this kind of interaction could be represented as attacking of water with acidic character on the basic site of M. Also, the calculations predict that the formation of monohydrated complex is an exothermic, down hill reaction, which is confirmed from the stabilization of the frontier molecular orbitals, oxygen lone-pair and the HOMO levels.