An extraction study of gallium, indium and thallium using TPASO as an extractant

A method is proposed for the extraction and individual separation of trivalent gallium, indium and thallium from salicylate media using triphenylarsine oxide dissolved in toluene as an extractant. The optimum extraction conditions are evaluated and described. The extracted metal ions are stripped and estimated spectrophotometrically following complexation with 4-(2-pyridylazo) resorcinol. A possible mechanism of the extraction is discussed. The method permits rapid and precise individual separation of gallium (III), indium (III) and thallium (III) and is applicable to the analysis of alloy samples.     

Tris(2-ethylhexyl)phosphate as an extractant for quadrivalent tin,with subsequent determination with pyrocatechol violet in alloy samples

The solvent extraction of tin(IV) from chloride media withtris(2-ethylhexyl)phosphate is presented. Tin(IV) is extracted quantitatively from 2.75–3.20 mol dm^–3 hydrochloric acid using 6.38–6.91 mol dm^–3 tris(2-ethyl-hexyl)phosphate dissolved in toluene as an extractant. After back-extraction of tin(IV) with water from thetris(2-ethylhexyl)phosphate phase, it is estimated spectrophotometrically following complexation with pyrocatechol violet. The recommended range for determination of tin(IV) is 10–100 g. The probable extracted species is SnCl₄·2TEHP. The method is applicable to the analysis of alloy samples with a detection limit of 0.4 g/ml (for 10 g of tin) and a relative standard deviation between 0.21–0.32%.     

Photometric determination of trivalent gallium,indium and thallium with Xylenol orange

Summary Xylenol orange reacts very sensitively with gallium(III), indium (III) and thallium(III) to form reddish violet colored chelates having _max 560 nm in case of Ga and In and _max 590 nm in case of Ti at P_H 4.0. The molar ratio for all the chelates is 1 1 (metal reagent). Optimum conditions including the range for adherence to Beer's law, effect of P_H on the color intensity, effect of excess reagent, and sensitivity are reported for the photometric determination of these metal ions using Xylenol orange.

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Zusammenfassung Xylenolorange reagiert sehr empfindlich mit Gallium(III), Indium(III) und Thallium(III) unter Bildung rötlich-violetter Chelate mit einem Absorptionsmaximum bei 560 nm im Falle von Ga und In bzw. 590 nm für Tl bei p_H 4,0. Das Molverhältnis ist in jedem Fall 11. Die besten Arbeitsbedingungen, der Gültigkeitsbereich des Beerschen Gesetzes, der Einfluß des P_H auf die Farbintensität und des Reagensüberschusses sowie die Empfindlichkeit werden für die photometrische Bestimmung der genannten Ionen angegeben.

     

Separation of uranium and thorium using tris(2-ethylhexyl) phosphate as extractant

The distribution behavior of uranium and thorium has been investigated in a biphasic system of different aqueous nitric acid concentrations and a solution of tris(2-ethylhexyl) phosphate (TEHP) inn-dodecane at 25°C. The effect of different uranium and thorium concentrations in the aqueous phase on the extraction of these metal ions is evaluated. These results indicate that TEHP is a better choice than tri-n-butyl phosphate (TBP) for the separation of²³³U from the irradiated thorium matrix.     

Di(2-ethylhexyl)sulfoxide as an extractant for plutonium(IV) from nitric acid medium

The liquid-liquid extraction behavior of plutonium(IV) from aqueous nitric acid media into n-dodecane by di(2-ethylhexyl)sulfoxide (DEHSO) was investigated over a wide range of conditions. Optimum-parameters such as the aqueous phase acidity, reagent and metal concentrations, etc., were established for efficient extraction-separation of tracer as well as macro levels of plutonium. It was found that the extraction increased with increasing nitric acid concentration up to 6M HNO₃ and then decreased. Extraction also increased with increasing extractant concentration. After loading of the organic phase with 2 to 50 mg/ml of U(VI), extractability of Pu(IV) became considerably lower. Recovery of Pu(IV) from the organic phase was accomplished using dilute uranium(IV) nitrate as the strippant.     

Bis(2-ethylhexyl)sulfoxide as an extractant for americium(III) from aqueous nitrate media

Solven extraction separation of americium(III) from dilute aqueous nitrate media into n-dodecane by bis(2-ethylhexyl)sulfoxide (BESO) has been investigated over a wide range of experimentgal conditioins. Very poor extractablity of Am(III), necessitated the use of calcium nitrate as the salting-out agent. Effects of certain variables such as acidity, extractant concentration, salting-out agent concentration, organic diluents on the metal extraction by BESO have been examined in detail. By increasing the concentration of BESO in organic phase or calcium nitrate in aqueous phase, nearly quantitative extraction of americium even from moderate acidity is accomplished. Slope analyses applied to Am(III) distribution experiments from acidic nitrate solutions indicate predominant formation of the risolvated organic phase complex, Am(NO₃)₃)·3BESO for which equilibrium constant is found to be, log K_x=1.99. Extraction behavior of Am(III) has also been evlauated in the presence of several water-miscible polar organic solvents to stuy their possible synergistic effects on its extraction. Extractability of americium increased 5 to 10-fold withi increasing conentration of some of these additives, with maximum enhancement being observed in the presence of acetone or acetonitrile. Recovery of BESO from loaded americium is easily obtained using dilute nitric acid as the strippant.     

Column chromatographic separation of gallium, indium and thallium

Distribution ratios are given for the extraction of gallium-(III), indium(III) and thallium(III) from aqueous solutions of hydrobromic acid into di-isopropy ether and isobutyl methyl ketone. Based on the results obtained, a scheme is presented for the quantitative separation of these elements from each other by liquid-liquid partition chromatography. The effect of a number of other metal ions upon the separation is also studied. The separation method has been applied to the analysis of a series of lead-indium alloys.     

Complexometric titration of gallium, indium and thallium(III) using sodium azide as a metal indicator

Summary Thallium(III) has been determined between pH 4.0 and 6.0 by titration against EDTA using sodium azide as indicator. The metal ion gives a bright yellow colour which is discharged at the equivalence point. Micro-quantities upto about 1 mg of the metal have been determined with accuracy. The end-point has also been determined photometrically. Gallium(III) and indium(III) can also be determined by back-titration of the excess of EDTA added to each of these ions against a standard ferric chloride solution using sodium azide as indicator.

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Zusammenfassung Thallium(III) wird durch Titration mit ÄDTA-Lösung bei pH 4,0–6,0 gegen Natriumazid als Indicator bestimmt. Der Umschlag am Endpunkt erfolgt von Gelb nach Farblos. Mikromengen bis zu 1 mg können mit guter Genauigkeit erfa\t werden. Die Bestimmung kann auch photometrisch durchgeführt werden. Gallium(III) und Indium(III) können durch Rücktitration von überschüssigem ÄDTA mit Eisen(III)-chloridlösung bestimmt werden, wobei ebenfalls Natriumazid als Indicator dient.

     

Separation studies of uranium and thorium using tetra(2-ethylhexyl) diglycolamide (TEHDGA) as an extractant

The extraction behavior of uranium, thorium and nitric acid has been investigated for the TEHDGA/isodecyl alcohol/n-dodecane solvent system. Conditional acid uptake constant (K _H) of TEHDGA/n-dodecane and the ratio of TEHDGA to nitric acid were obtained as 1.72 and 1:0.96, respectively. The extracted species of uranium and thorium in the organic phase were found to be UO₂(NO₃)₂·2TEHDGA and Th(NO₃)₄·2TEHDGA. A workable separation factor (D _Th/D _U) of the order of 300 was observed between thorium and uranium in the nitric acid range of 0.5M to 1.5M. Similar separation factor was also achieved at higher acidity when thorium was present in large concentration compared to uranium. These results indicate that TEHDGA solvent system could be a potential candidate for separation of thorium from uranium.     

Thermal decomposition of the solvent-extracted chloro complexes of trivalent gallium,indium and thallium with trioctylamine and trioctylmethylammonium chloride

The complexes of trivalent gallium, indium and thallium with trioctylamine (TOA, R₃N) and trioctylmethylammonium chloride (TOMAC, R₃RNCl) were prepared by drying in vacuo the organic extracts from aqueous solutions containing the chlorides of their metals with TOA and TOMAC in benzene: R₃NHGaCl₄, (R₃NH)₂InCl₅, R₃NHTlCl₄, R₃R'NGaCl₄, R₃R'NInCl₄ and R₃RTlCl₄. The prepared complexes were examined by TG and DTA under an atmosphere of nitrogen, and the products of their thermal decompositions, such as volatile matter and residues, were examined by gas chromatography, X-ay diffraction study and infrared spectrophotometry. It was found that the complexes of these trivalent metals with TOA and TOMAC decompose thermally to the chlorides (GaCl₃, InCl₃ and TlCl) through the cracking of alkyl groups.

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Zusammenfassung Komplexe von dreiwertigem Gallium, Indium und Thallium mit Trioctylamin (TOA, R₃N) und Trioctylmcthylarnmonium-Hydrochlorid (TOMAC, R₃R'NCl) wurden durch Trocknung der benzolischen Extrakte der die Metallchloride mit TOA bzw. TOMAC enthaltenden wässrigen Lösungen im Vakuum dargestellt: R₃NHGaCl₄, (R₃NH)₂InCl₅, R₃NHTlCl₄, R₃R'NGaCl₄, R₃R'NInCl₄ und R₃R'TlCl₄. Die dargestellten Komplexe wurden durch TG und DTA in Stickstoffatmosphäre untersucht. Die Produkte der thermischen Zersetzung, flüchtige Substanzen und Rückstände, wurden gas-chromatographisch, röntgendiffraktometrisch und 1R-spektrophotometrisch untersucht. Es wurde festgestellt, daß die Komplexe dieser dreiwertigen Metalle sich thermisch durch Krackung der Alkylgruppen zu den Chloriden (GaCl₃, InCl₃ und TlCl₃) zersetzen.

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, (, R₃N) ( , R₃RNCl) R₃NHGaCl₄, (R₃NH)₂InCl₅, R₃NHTlCl₄, R₃RNGaCl₄, R₃RNInCl₄ R₃RNTlCl₄ , . , , - . , (GaCl₃, InCl₃ TlCl) c .

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Paper presented at the 1985 World Conference on Thermal Analysis, Bad Hofgastein, Austria.

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We wish to thank the Research and Development Laboratory, Swiss Aluminium Ltd., Neuhausen, Switzerland, for the gift of gallium metal, and the Koei Chemical Co. Ltd. for samples of TOA and TOMAC.     

Tris(difluoro and trifluorobutane-2,4-dionato) gallium(III) and indium(III) complexes

Eight tris(β-diketonate)gallium(III) and seven tris(β-diketonate)-indium(III) complexes M(RCOCH-COR′)₃, with R′being difluoromethyl and trifluoromethyl substituents and R′ being methyl, phenyl, aryl, 2′-naphthyl and 2′-thienyl substituents have been studied by nuclear magnetic resonance spectroscopy. The complexes are all nonrigid (fluxional) and their ¹⁹F NMR spectra show four resonances in the nonexchanging regions due to cis and trans isomers. A variable low temperature study of these complexes was done for the gallium chelates and activation parameters are calculated. The indium complexes all have nonexchanging regions below ?100°C. The ¹³C NMR data on the complexes are also reported.     

Tris(2-ethylhexyl)phosphine oxide as an effective solvent mediator for constructing a serotonin-selective membrane electrode

A series of solvent mediators containing a phosphoryl (PO) group, such as tris(2-ethylhexyl)phosphate, bis(2-ethylhexyl) 2-ethylhexylphosphonate, 2-ethylhexyl bis(2-ethylhexyl)phosphinate, and tris(2-ethylhexyl)phosphine oxide, were used to construct serotonin-selective membrane electrodes. We found that replacing the alkoxy groups attached to phosphorus atoms in PO groups with alkyl groups strengthened the response of the electrode to serotonin, suppressing remarkably interference from inorganic cations, such as Na⁺. Thus, an electrode combining tris(2-ethylhexyl)phosphine oxide with an ion-exchanger, sodium tetrakis[3,5-bis(2-methoxyhexafluoro-2-propyl)phenyl]borate, gave a detection limit of 9 × 10⁻⁶ M with a slope of 55.2 mV per concentration decade in physiological saline containing 150 mM NaCl and 10 mM NaH₂PO₄/Na₂HPO₄ (pH 7.4). This is the best detection limit of any serotonin-selective electrode developed to date. The selectivity of this electrode for serotonin was over 10³ times that for inorganic cations, such as Na⁺ and K⁺, and lipophilic quaternary ammonium ions, such as acetylcholine and (C₂H₅)₄N⁺. Using the electrode, we measured the amount of serotonin released from platelets and found that the results agreed well with those obtained by a conventional fluorimetric assay of serotonin.     

Synthesis and Structure of Tris(8-mercaptoquinolinato)thallium and Tris(8-hydroxyquinolinato)thallium Monohydrate

Tris(8-mercaptoquinolinato)thallium Tl(C₉H₆NS)₃ and tris(8-hydroxyquinolinato)thallium monohydrate Tl(C₉H₆NO)₃·H₂O have been synthesized. Their structures have been confirmed by X-ray crystallographic analysis.     

Solvent extraction and separation of gallium, indium and thallium with N-benzylaniline

A simple and rapid method is proposed for the separation of tervalent gallium, indium and thallium by solvent extraction with N-benzylaniline in chloroform from different concentrations of hydrochloric acid. Thallium and gallium are extracted from 1M and 7.0-7.5M hydrochloric acid respectively. Indium is finally extracted from hydriodic acid. These metals in the final extracts are determined complexometrically. Interference from some cations can easily be eliminated by reduction with sulphite, followed by selective oxidation of thallium(I) to thallium(III) with saturated bromine water, and from others by the use of thioglycollic acid as a masking agent in the extraction of gallium and indium. Most common anions cause no interference. Log-log plots of distribution coefficients vs. concentration of amine for gallium, indium and thallium indicate a 2:1 limiting mole ratio of amine to these metals.     

n-octylphenyl hydrogen phosphate as an extractant for some lanthanides

n-Octylphenyl hydrogen phosphate (OPHP) is examined for the extraction of neodynium, gadolinium and terbium. The effects of pH and metal ion and extractant concentrations are reported. The extraction constants are 39.5, 40.7 and 43.4 for Nd, Gd and Tb, respectively. The extraction efficiency of OPHP for these lanthanides is bettter than that of commoner alkylphosphorus acids.     

Separation of gallium, indium and thallium by extraction with n-octylaniline in chloroform

Extraction of gallium(III), indium(III) and thallium(III) with n-octylaniline in chloroform at various concentrations of hydrogen halide acids (HCl, HBr, HI) has been studied and a scheme for their separation proposed. The procedure can be successfully applied to the separation and determination of gallium in presence of mercury, bismuth, manganese, zinc and lead; indium in presence of bismuth, antimony, lead, mercury, cadmium and zinc; and thallium in presence of mercury, cadmium, manganese, aluminium, tin and antimony. The advantage of the method is that the reagent can be recovered for reuse. The method is simple, rapid, and effects clear-cut separation.     

3,5,7,4'-Tetrahydroxyflavone (kaempferol) as a chromogenic reagent for gallium and indium

3,5,7,4'-Tetrahydroxyflavone (kaempferol) forms yellow chelates with indium and gallium. Based on this reaction, a sensitive spectrophotometric method for the determination of gallium and indium alone and in presence of other metals and alloys has been developed. Beer's law is obeyed up to 2.8 and 1.44 ppm for indium and gallium respectively.