A new solvent system for the separation of Th4+, UO 2 2+ and Zr4+ in the presence of common anions by thin-layer chromatography

Summary A TLC method has been developed for separating Th⁴⁺, UO₂ ²⁺ and Zr⁴⁺ in the presence of some common anions using a dimethylamine/acetone/formic acid mobile phase. Capacity factors, separation factors and resolution for the separation of Th⁴⁺ from UO₂ ²⁺ have been evaluated. The effect of the pH of the sample on R_F values of Th⁴⁺, UO₂ ²⁺, Ni²⁺ and Cu²⁺ has also been examined.     

Extraction of microamounts of europium and americium into nitrobenzene by using hydrogen dicarbollylcobaltate in the presence of diphenyl-N-butylcarbamoylmethyl phosphine oxide

Extraction of microamounts of europium and americium by a nitrobenzene solution of hydrogen dicarbollylcobaltate (H⁺B⁻) in the presence of diphenyl-N-butylcarbamoylmethyl phosphine oxide (DPBCMPO, L) has been investigated. The equilibrium data have been explained assuming that the complexes HL⁺, HL₂⁺, ML₂³⁺, ML₃³⁺ and ML₄³⁺ (M³⁺ = Eu³⁺, Am³⁺) are extracted into the organic phase. The values of extraction and stability constants of the species in nitrobenzene saturated with water have been determined. It has been found that the stability constants of the corresponding complexes EuL _n ³⁺ and AmL _n ³⁺, where n = 2, 3, 4 and L is DPBCMPO, in water saturated nitrobenzene are comparable.     

Extraction of calcium into nitrobenzene by using hydrogen dicarbollylcobaltate in the presence of 12-crown-4

Extraction of microamounts of calcium by a nitrobenzene solution of hydrogen dicarbollylcobaltate (H⁺B^-) in the presence of 12-crown-4 (12C4,L) has been investigated. The equilibrium data have been explained assuming that the complexes HL⁺, HL₂ ⁺, CaL²⁺ and CaL₂ ²⁺ are extracted into the organic phase. The values of extraction and stability constants of the species in nitrobenzene saturated with water have been determined.     

Preconcentration and recovery of uranium and thorium from Indian monazite sand by using a modified fly ash bed

Adsorption of uranium, as UO₂ ²⁺, and thorium, as Th⁴⁺, has been studied using a modified fly ash bed. Effects of pH and various ions like La³⁺, Fe³⁺, Ce⁴⁺, SiO₃ ^2- etc., have been examined. Synthetic mixtures of UO₂ ²⁺ and Th⁴⁺ in different concentrations were passed through the bed and eluted separately with various selective reagents viz. ammonium carbonate, sodium carbonate and acetic acid-sodium hydroxide buffer. Separations of these elements at ppm level are shown to be very effective. The separation of uranium and thorium in the presence of lanthanides in monazite sand has been studied successfully. In the analysis of monazite sand, the oxalate precipitation has been avoided. The method is simple and of very low cost. The modified fly ash bed can also be used to remove uranium from contaminated water.     

Kinetics of the Formation of Goethite in the Presence of Sulfates and Chlorides of Monovalent Cations

The synthesis of goethite by oxidation of Fe²⁺in presence of metallic iron was undertaken in an aqueous medium containing indifferent salts such as Na₂SO₄, (NH₄)₂SO₄, NaCl, and NH₄Cl. Temperature and bubbling air rate were maintained, respectively, at 70°C and 1 L/min. The influence of anions and cations on the kinetics of each step of the process has been followed distinctly, the iron dissolution rate has been determined by the variation of the medium acidity, and the precipitation of goethite has been determined by gravimetric measurements. With respect to Cl⁻, the SO₄²⁻anion decreases the rate of the two reactions. NH₄⁺acts as an inhibitor when it is present at low concentrations and as an accelerator for higher concentrations; the limit corresponding to the change of NH₄⁺behavior depends on the nature of the counter ion. The reaction product is composed of pure goethite in the presence of sulfate salts, whereas a mixture of goethite and lepidocrocite, respectively, 60–70 and 40–30%, was observed in the presence of chloride salts.     

Effect of p-tert-butylcalix[4]arene fitted with phosphinoyl pendant arms as synergistic agent in the solvent extraction of trivalent lanthanoids with 4,4,4-trifluoro-1-(2-thienyl)-1,3-butanedione and structural study of solid complexes by IR,NMR and X-ray

The synergistic solvent extraction of five selected lanthanoid ions (La³⁺, Nd³⁺, Eu³⁺, Ho³⁺ and Lu³⁺) with 4,4,4-trifluoro-1-(2-thienyl)-1,3-butanedione (HL) and 5,11,17,23-tetra-tert-butyl-25,26,27,28-tetrakis-(dimethylphosphinoylmethoxy)calix[4]arene, (S) in CHCl₃ has been studied. It was found that in presence of this phosphorus-containing calix[4]arene the lanthanoid ions have been extracted as [LnL₃S₂]. The values of the equilibrium constants and the separation factor have been calculated. The influence of the synergistic agent on the extraction process has been discussed.     

Effects of iron(III) chloro complexes on the polymerization of styrene

The polymerization of styrene initiated by 2,2′-azobisisobutyronitrile has been studied in N,N-dimethylformamide solution at 60°C in the presence of hexakis(N,N-dimethylformamide) iron(III) tetrafluoroborate alone, and also in the presence of added lithium chloride. The presence of Fe(DMF)₆³⁺ ions in the polymerizing systems caused retardation, but iron(III) chloro complexes produced well defined inhibition periods. Velocity constants at 60°C for polystyryl radicals towards Fe(DMF)₆³⁺, Fe(DMF)₅Cl²⁺, Fe(DMF)₄Cl₂⁺, and FeCl₄^? ions were calculated to be 847, 4.15 × 10⁴, 6.55 × 10⁴, and 3.14 × 10⁴ l./mole-sec, respectively. Values of the initiator efficiency f for most systems investigated ranged from 0.59 to 0.62.     

1-(d-Glucopyranosyl-2′-deoxy-2′-iminomethyl)-2-hydroxynaphthalene as chemo-sensor for Fe in aqueous HEPES buffer based on colour changes observable with the naked eye

A new glucose-based C2-derivatized colorimetric chemo-sensor (L₁) has been synthesized by a one-step condensation of glucosamine and 2-hydroxy-1-naphthaldehyde for the recognition of transition metal ions. Among the eleven metal ions studied, viz., Mg²⁺, Ca²⁺, Mn²⁺, Fe²⁺, Fe³⁺, Co²⁺, Ni²⁺, Cu²⁺, Zn²⁺, Cd²⁺ and Hg²⁺, L₁ results in visual colour change only in the presence of Fe²⁺, Fe³⁺and Cu²⁺ in methanol. However, in an aqueous HEPES buffer (pH 7.2) it is only the Fe³⁺ that gives a distinct visual colour change even in the presence of other metal ions, up to a concentration of 280 ppb. The changes have been explained based on the complex formed, and the composition has been determined to be 2:1 between L₁ and Fe³⁺ based on Job’s plot as well as ESI MS. The structure of the proposed complex has been derived based on HF/6-31G calculations.     

Extraction of microamounts of europium and americium by using hydrogen dicarbollylcobaltate in the presence of dibutyl diethylcarbamoylmethylene phosphonate

Extraction of microamounts of europium and americium by a nitrobenzene solution of hydrogen dicarbollylcobaltate (H⁺B⁻) in the presence of dibutyl diethylcarbamoylmethylene phosphonate (DBDECMP, L) has been investigated. The equilibrium data have been explained assuming that the complexes HL⁺, HL₂²⁺ ML₃³⁺ and ML₄³⁺ (M³⁺ = Eu³⁺, Am³⁺) are extracted into the organic phase. The values of extraction and stability constants of the species in nitrobenzene saturated with water have been determined.     

Solvent extraction of strontium into nitrobenzene using hydrogen dicarbollylcobaltate in the presence of 12-crown-4

Extraction of microamounts of strontium by a nitrobenzene solution of hydrogen dicarbollylcobaltate (H⁺B^-) in the presence of 12-crown-4 (12C4,L) has been investigated. The equilibrium data have been explained assuming that the complexes HL⁺, HL₂ ⁺, SrL²⁺ and SrL₂ ^+2- are extracted into the organic phase. The values of extraction and stability constants of the species in nitrobenzene saturated with water have been determined.     

Beam studies of energy and lifetime dependence of unimolecular decay: the extent of internal equilibration

The reaction C₂H₄⁺ + C₂H₄ → CH₃ + C₃H₅⁺, known to pass through a persistent C₄H₈⁺ complex, has been used to test accepted models of unimolecular decay. Experimental product translational energy spectra are interpreted using an expression derived from RRKM theory. Data and calculations agree well, but only if the assumption of complete energy equilibration prior to decay is discarded.     

A new chelating resin containing 2-aminothiophenol: Synthesis characterization and determination of mercury in waste water using <Superscript>203</Superscript>Hg radiotracer

A new stable chelating resin was synthesized by incorporating 2-aminothiophenol into Merrifield polymer through C-N covalent bond and characterized by elemental analysis, IR and thermal study. The sorption capacity of the newly formed resin for Hg²⁺ as a function of pH has been studied using ²⁰³Hg radioisotope. The resin exhibits no affinity to alkali or alkaline earth metal ions and common anions. The separation of mercury(II) in presence of different alkali and alkaline earth metal ions (Na⁺, K⁺, Mg²⁺, Ca²⁺, Sr²⁺, Ba²⁺), common anions (ClO₄ ⁻, SO₄ ²⁻) and other diverse ions (Ag⁺, Cu²⁺, Pb²⁺, Fe³⁺, Ni²⁺ and Zn²⁺) has been checked. In column operation it has been observed that Hg²⁺ content of the waste water can be removed at usual pH of natural water. Mercury was determined by isotope dilution method and the concentration of Hg²⁺ in the waste water spiked with ²⁰³Hg was found to be 0.05 to 0.09 μg/ml.     

Extraction of microamounts of calcium,strontium and barium into nitrobenzene by using hydrogen dicarbollylcobaltate in the presence of dibenzo-18-crown-6

Extraction of microamounts of calcium, strontium and barium by a nitrobenzene solution of hydrogen dicarbollylcobaltate (H⁺B⁻) in the presence of dibenzo-18-crown-6 (DB18C6, L) has been investigated. The equilibrium data have been explained assuming that the complexes HL⁺, ML²⁺, ML₂²⁺ and MHL₂³⁺ (M²⁺ = Ca²⁺, Sr²⁺, Ba²⁺) are extracted into the organic phase. The values of extraction and stability constants of the species in nitrobenzene saturated with water have been determined.     

Prediction of KSP from Rf Values: Thin Layer Chromatography of 47 Metal Ions on Stannic Arsenate in Aqueous Hydrochloric Acid Systems

Abstract

The adsorption behaviour of 47 metal ions has been studied in aqueous HCl systems using stannic ersenate layers. The effect of solvent pH on R_f alongwith the complexation effect of HCl has been investigated. On the basis of R_f values the K_SP of some metel arsenates have been predicted. HCl has been utilized to resolve some binary and ternary mixtures such as Be²⁺ - Mg²⁺, Zr⁴⁺ - La³⁺, Th⁴⁺ - Ce⁴⁺, Th⁴⁺ - UO²⁺ ₂, Cr³⁺ - Mo⁶⁺ or W⁶⁺, Sb³⁺ - Bi³⁺ - Cd²⁺ and Ag⁺ - Cu²⁺ - Cd²⁺.     

Extraction distributions of microamounts of strontium and barium in the two-phase water-HCl-nitrobenzene-dibenzo-21-crown-7-hydrogen dicarbollylcobaltate system

Extraction of microamounts of strontium and barium by a nitrobenzene solution of hydrogen dicarbollylcobaltate (H⁺B⁻) in the presence of dibenzo-21-crown-7 (DB21C7, L) has been investigated. The equilibrium data have been explained assuming that the complexes HL⁺, ML²⁺, ML₂²⁺ and MHL₂³⁺ (M²⁺ = Sr²⁺, Ba²⁺) are extracted into the organic phase. The values of extraction and stability constants of the species in nitrobenzene saturated with water have been determined.     

Extraction of calcium and strontium into nitrobenzene by using hydrogen dicarbollylcobaltate in the presence of 1,2-(diphenylphosphino)ethylene dioxide

Extraction of microamounts of calcium and strontium by a nitrobenzene solution of hydrogen dicarbollylcobaltate (H⁺B⁻) in the presence of 1,2-(diphenylphosphino)ethylene dioxide (DPPEDO, L) has been investigated. The equilibrium data have been explained assuming that the species HL⁺, HL₂ ⁺, CaL₂ ²⁺, CaL₃ ²⁺, CaL₄ ²⁺, SrL₂ ²⁺ and SrL₃ ²⁺ are extracted into the organic phase. The values of extraction and stability constants of the cationic complexes in nitrobenzene saturated with water have been determined. In the considered nitrobenzene medium, it was found that the stability constants of the CaL _n ²⁺ complexes, where n = 2, 3 and L is DPPEDO, are somewhat higher than those of the corresponding complex species SrL _n ²⁺.     

Spectrophotometric determination of molybdenum(vi) with benzoylacetanilide

Abstract

The complex formed between molybdenum(VI) and benzoylacetanilide in the pH range 0.6 and 1.9 has been extracted into methyl isobutyl ketone and the absorbance has been measured at 410 mμ. Quantities of 0.15 to 2.10 mg of molybdenum have been determined with a standard deviation of 0.6%. The color is stable up to 2 hours. The presence of Co²⁺, Ni²⁺, Zn²⁺, Mn²⁺, Be²⁺, Al³⁺, Cr³⁺, Ce⁴⁺, Th⁴⁺ or UO²⁺ ₂ up to 100 μg causes no interference. Ordinarily, Fe³⁺ interferes with the determination, but when masked with 1 ml of 0.5% solution of ascorbic acid the tolerance limit is 10 mg. Thus, molybdenum can be determined in steel when present in amounts as low as 0.26%.     

Analytical aspects of some organic acids

Summary o-Phenylenedioxydiacetic acid has been found to be a selective reagent for the estimation of zirconium. As little as 2.1 mg of zirconium can be easily estimated. The composition of the precipitate varies somewhat and therefore, direct weighing is not possible. This difficulty is overcome by igniting as oxide. Be²⁺, Ca²⁺, Ba²⁺, Zn²⁺, Hg²⁺, Al³⁺, Ce³⁺, Ti⁴⁺, Th⁴⁺, UO²⁺, Mn²⁺, Fe³⁺, Co²⁺, and Ni²⁺, ions do not interfere. Although V₂O₂ ⁴⁺ and Cr³⁺ ions are not precipitated in neutral or slightly acidic solutions they contaminate the zirconium precipitate, at about 0.30 N HCl concentration. The amount of contamination is so small that it is removed by double precipitation. This method gives satisfactory results even in the presence of small amounts of SO₄ ^2–ions.     

Extraction of85Sr by the nitrobenzene solution of bis-1,2-dicarbollylcobaltate in the presence of dibenzo-18-crown-6

Extraction of strontium by the nitrobenzene solution of bis-1,2-dicarbollylcobaltate in the presence of dibenzo-18-crown-6 (DB18C6, L) has been investigated. the equilibrium data and the typical maxima concerning the dependencies of the Sr distribution ratios on the total analytical concentration of DB18C6 in the system under study can be explained assuming that the particles Sr²⁺, SrL²⁺, SrL₂ ²⁺, SrHL³⁺ and SrHL₂ ³⁺ are extracted into the nitrobenzene phase. The values of the corresponding extraction and stability constants of the extracted species in nitrobenzene saturated with water have been determined.     

Solvent extraction of microamounts of strontium and barium from water into nitrobenzene using hydrogen dicarbollylcobaltate in the presence of benzo-18-crown-6

Extraction of microamounts of strontium and barium by a nitrobenzene solution of hydrogen dicarbollylcobaltate (H⁺B⁻¹) in the presence of benzo-18-crown-6 (B18C6, L) has been investigated. The equilibrium data been explained assuming that the complexes HL⁺, ML²⁺, ML₂²⁺ and MHL₂³⁺ (M²⁺ = Sr²⁺, Ba²⁺) are extracted into the organic phase. The values of extraction and stability constants of the species in nitrobenzene saturated with water have been determined.