Tris(2-ethylhexyl)phosphate as an extractant for trivalent gallium, indium and thallium

A systematic study of solvent extraction behaviour of gallium(III), indium(III) and thallium(III) with tris(2-ethylhexyl)phosphate from salicylate media has been undertaken and a scheme for their separation is proposed. The optimum extraction conditions are evaluated and described. The method is applicable to the analysis of standard aluminium and aluminium alloys samples. The results obtained are reproducible and accurate.     

Design of amphoteric mixed oxides of zinc and Group 3 elements (Al, Ga, In): migration effects on basic features

The design of new amphoteric catalysts is of great interest for several industrial processes, especially those covering dehydration and dehydrogenation phenomena. Adsorption microcalorimetry was used to monitor the design of mixed oxides of zinc with Group 3 elements (aluminium, gallium, indium) with amphoteric character and enhanced specific surface area. Acid-base features were found to evolve non-linearly with the relative amounts of metal, and the strengths of the created acidic or basic sites were measured by adsorption microcalorimetry. A panel of bifunctional catalysts of various acid-base (amounts, strengths) and redox character was obtained. Besides, special interest was given to In-Zn mixed oxides for their enhanced basicity: this series of catalysts displays important basic features of high strength (q(diff) (SO? ads.) > 200 kJ mol(SO?)?1 in substantial amounts (1 - 2 μmol m(catalyst)?2), whose impact on efficiency or selectivity in catalytic dehydration/dehydrogenation can be valuable.     

The fluorescence properties of metal complexes of alkyl derivatives of aromatic schiff bases

Seventeen alkylated salicylidene-o-aminophenol derivatives were tested as fluorimetric reagents for aluminium, gallium, indium, scandium and beryllium. The aluminium, gallium and beryllium complexes are intensely fluorescent, and the scandium and indium complexes weakly fluorescent. The fluorescence properties of the aluminium, gallium and beryllium complexes were studied and conditions for the fluorimetric determination of these metals were established. 2-Hydroxy-4-methylaniline-N-2-hydroxy-4-methyl-benzylidene is a good reagent because of the reproducibility and sensitivity of the fluorescence. The optimal ranges for determination are 0.005–3 mg Al/25 ml, 0.1–7 μg Ga/25 ml and 0.02–7 μg Be/25 ml. In all cases, 1:1 metal—ligand complexes are formed. Optimal reaction conditions and interference studies are reported.     

Simultaneous Determination of Gallium(III) and Indium(III) in Urine and Water Samples with Cloud Point Extraction and by Inductively Coupled Plasma Optical Emission Spectrometry

A simple, sensitive, and selective method for the determination of gallium and indium in different samples at trace levels is presented. This method was based on complexation of analyzes with 2-(5-bromo-2- pyridylazo)-5-diethylaminophenol (5-Br-PADAP) in the presence of t-octylphenoxy-polyethoxyethanol (Triton X-100). After phase separation, the analyzed concentrations were determined by inductively coupled plasma optical emission spectrometry. Quantitative extraction of gallium and indium was performed at pH 7.0, 1.7 mmol L^?1, 5-Br-PADAP, 1.3% (w/v) Triton X-100 and at 75°C. The relative standard deviations (RSD) of this method were between 0.3% and 1.6% (C = 20 ng mL^?1, n = 9). The calibration curve is linear over the concentration range 6–200 ng mL^?1 for gallium and 2–200 ng mL^?1 for indium, respectively. The limits of detection (LOD) for gallium and indium were 0.72 and 0.28 ng mL^?1, respectively. The results showed the developed method was not susceptible to matrix effects, providing recoveries between 98% and 102%. The accuracy of the developed method was evaluated by the analysis of spiked certified reference materials. The developed method was successfully applied to gallium and indium determination in urine and lake water with satisfactory results.     

Studies on derivatives of 8-hydroxyquinoline (oxine). the sensitivity and selectivity of 5-nitroso-oxine and 2-methyl-5-nitroso-oxine towards the group IIIB metals

2-Methyl-5-nitroso-8-hydroxyquinoline (2-methyl-5-nitroso-oxine), hitherto undescribed, has been prepared. The sensitivity and selectivity of this oxine derivative, together with 5-nitroso oxine, and 2-methyl-oxine towards aluminium, yttrium, gallium, indium and thallium(III) have been investigated. A gradation in selectivity is found. With oxine, precipitation occurs with all the above metals under the conditions of the test. With 2-methyl-oxine, precipitation occurs with all metals with the exception of aluminium. With 5-nitroso-oxine, no precipitation occurs with aluminium, yttrium, gallium and indium, and with 2-methyl-5-mtroso-oxine, no precipitation occurs with any metal in Group III B. A possible explanation for this behaviour is advanced.     

Simultaneous determination of gallium(III) and indium(III) by derivative spectrophotometry

A simple, selective and sensitive derivative spectrophotometric method is proposed for the simultaneous determination of gallium(III) and indium(III) in mixtures using 1-(2-pyridylazo)-2-naphthol in cationic micellar medium, without any prior separation. Beer's law is obeyed between 2.80x10(-1)-3.63 and 4.60x10(-1)-9.20 mug ml(-1) concentration of Ga(III) and In(III) at 550 and 542 nm, the isodifferential points of indium and gallium complexes in the first-order derivative mode, respectively. The proposed method is successfully applied for the determination of gallium and indium in standard reference materials and synthetic binary mixtures with a relative error of +/-2.07 and +/-2.55%, respectively.     

Determination of traces of gallium and indium in ores by electrothermal-atomization atomic absorption spectrometry with matrix modifications

Methods were developed for the determination of gallium and indium in complex ores by electrothermal-atomization atomic absorption Spectrometry using matrix modifications. Nickel and nickel-ammonium sulfate as matrix modifier has enhanced the absorption signals for gallium and indium, respectively, eliminating the matrix interferences to allow their solutions in nitric acid to be used as calibration standards. No matrix separations are necessary. Results are quoted for a variety of black ore samples (Kuroko). The RSDs are 7.0% for gallium and 5.3% for indium at their 10 g/g levels, and the inverse sensitivities are 20 pg of gallium and 38 pg of indium for respective 1% absorption.     

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.     

Chlorometallate(III) ionic liquids as Lewis acidic catalysts--a quantitative study of acceptor properties

The Gutmann Acceptor Number (AN), which is a quantitative measure of Lewis acidity, has been estimated using the (31)P NMR chemical shift of a probe molecule, triethylphosphine oxide, for a range of chlorometallate(III) ionic liquids, based on Group 13 metals (aluminium(III), gallium(III) and indium(III)) and the 1-octyl-3-methylimidazolium cation, at different compositions. The results were interpreted in terms of extant speciation studies of chlorometallate(III) ionic liquids, and compared with a range of standard molecular solvents and acids. The value of these data were illustrated in terms of the selection of appropriate ionic liquids for specific applications.     

Cation Exchange Separation of Thallium (I) From Other Elements In Mixed Solvents

Abstract

The cation exchange chromatographic behaviour of thallium (I) on Dowex 50W-X8 was carried out in mixed solvents. Nitric, sulphuric, perchloric acid and their salts, as well as in mixtures of 2 M nitric acid with methanol, ethanol, acetone, dioxane and titrahydrofuran, were studied as the eluants. In comparison with other elements, since thallium was weakly sorbed, it was first eluted, while strongly bound elements like manganese, magnesium, cobalt, indium, gallium, zinc, iron, scandium, yttrium, aluminium, calcium, strontium, and barium were subsequently eluted. The best separations were possible from nitric acid in the presence of non-aqueous solvents such as methanol and ethanol.     

Metal and metalloid indicator electrodes for the non-aqueous potentiometric titration of weak acids: comparative evaluation of group III, IV and V main-group elements

Indicator electrodes constructed from aluminium, gallium, indium, thallium, carbon, silicon, germanium, tin, lead, arsenic, antimony and bismuth have been evaluated for the potentiometric titration of solutions of benzoic acid in dimethylformamide and 4-methyl-2-pentanone. The aluminium, gallium, silicon and arsenic electrodes have also been evaluated for the determination of 3,5-xylenol in the same two solvents. Aluminium, gallium, indium, silicon, germanium, antimony and bismuth electrodes are superior to, or compare favourably with, a glass electrode for the determination of benzoic acid, when the criterion of efficiency is the sharpness of the end-point inflexion. In non-aqueous titrations of 3,5-xylenol, aluminium and gallium electrodes are similar in efficiency to the glass electrode for determinations in dimethylformamide solution, while the gallium electrode is superior to the glass electrode when 4-methyl-2-pentanone is the solvent. Possible relationships between the properties of the electrode element and the end-point sharpness when it is used as an indicator electrode are briefly considered.     

Spectrophotometric determination of traces of gallium and indium with 1-(2-pyridylazo)-2-naphthol

1-(2-Pyridylazo)-2-naphthol (PAN) reacts with either gallium or indium at pH 5–6 giving a red complex in an aqueous medium in the presence of N.N-dimethyl-formamide. The maximum absorption of both PAN complexes of gallium and indium in an aqueous solution is at 545 mμ. The gallium-PAN complex shows a characteristic enhancement of color by addition of small amounts of ethers. Based on this selective enhancement reaction, gallium can be determined in the presence of other metals without separation. The results of determining gallium and indium in the presence of each other are reported. Both gallium and indium form M₂(PAN)₃; but in the presence of certain organic solvents, a different gallium complex, Ga(PAN)₅, and the same indium complex, In₂(PAN)₃, are formed. The reaction of PAN with cadmium can be masked by iodide; an example of determining indium in the presence of cadmium is given. The PAN method has a sensitivity of 0.003 μg/cm² for gallium and 0.005μg/cm² for indium and an absorptivity of 24,900 for the Ga-PAN complex and of 24,500 for the In-PAN complex, respectively. The methods have been successfully applied to the determination of both gallium and indium in germanium thin films.     

Direct titrimetric microdetermination of thallium(I), indium,and gallium(III) separately. I. Microdetermination of indium-thallium(I) and indium-gallium(III) in one solution without separation

Thallium, indium, and gallium are determined in micro amounts quantitatively by direct titrations against hippuric acid separately and in the presence of each other in different sets without separation. Thallium, indium, and gallium form complexes with hippuric acid in the ratio of 1:1 and 1:3. Maximum error in determination of thallium, indium, and gallium is 1.0 and 1.2%, respectively. In separate titrations of the three metals ions interference by different metals ions has also been observed; and the order of interference by metals ions on Tl, In, and Ga is Tl > In > Ga.     

Kinetic spectrophotometric determination of indium/gallium mixtures

A kinetic method is presented for the determination of 0.5–5 μg ml^?1 gallium based on its activating effect on the copper(II)-catalyzed oxidation of 4,4′-dihydroxybenzophenone thiosemicarbazone by hydrogen peroxide. The reaction is monitored spectrophotometrically at 415 nm. Two sets of reaction conditions are established; one for the direct determination of gallium, and another, in which indium affects the gallium response, for determination of indium. Mixtures of these cations can be determined at μg ml^?1 levels and in gallium/indium ratios from 7.5:1 to 1:1.6, with an accuracy and precision of ca. 4.5%.     

Propriétés des oxinates d'aluminium,de gallium et d'Indium.: Séparation du gallium par extraction par le chloroforme

A study has been made of the solubility in water as a function of pH of oxine and of the oxinatus of aluminium, gallium and indium, as well as their solubility in chloroform.The curves showing the partition between chloroform and water as a function of pu have been established.Gallium can be separated, from aluminium by extraction of the oxinate al pH₂O. It is possible by this means to separate one part of gallium from 10¹ parts of aluminium. The formation of the oxinates serves as a basis of an acidimetric determination of the ions Al⁺³, Ga⁺³ and In⁺³.     

Utility of 1-octanol/octane mixed solvents for the solvent extraction of aluminum(III), gallium(III), and indium(III) with 8-quinolinol.

Using 1-octanol/octane mixed solvents, the extraction of aluminum(III), gallium(III) and indium(III) with 8-quinolinol was carried out at 25 degrees C. The formation constants of the respective metal(III) 8-quinolinolates in the aqueous phase and their partition constants between the mixed solvents and water were determined based on an analysis of the extraction equilibria. The relationship between the partition constants of 8-quinolinol and its complexes was analyzed by the regular solution theory. The molar volumes of aluminum(III), gallium(III) and indium(III) 8-quinolinolates, calculated from the present results, suggest that the electrostriction effect functions in complex forming. It has been found that octane/1-octanol mixed solvents were available not only for the extraction of metal ions, but also for determining the formation constants of these metal 8-quinolinolates in the aqueous phase and their partition constants.     

Photometric determination of gallium with rhodamine b

Gallium is extractable as rhodamine B chlorogallate with benzene from 6M hydrochloric acid, and can be determined absorptiometrically or fluorimetrically in the extract. The interference of iron(III) is avoided by first separating gallium by extraction with isopropyl ether from hydrochloric acid solution containing titanous chloride. Traces of gallium can be determined in the presence of aluminium, indium, zinc, antimony, thallium, tungsten and other elements.     

Neutral carbene analogues of the heaviest Group 13 elements: consideration of electronic and steric effects on structure and stability

The neutral monovalent Group 13 beta-diketiminato complexes [CH{(CF3)2CN-2,6-iPr2C6H3}2In] and [CH{(Me)2CN-2,6-iPr2C6H3}2Tl] have been synthesised by analogous 'one-pot' procedures involving reaction of [KN(SiMe3)2] with the appropriate beta-imino-enamine and Group 13 iodide. The structure of the indium complex reveals that replacement of the ligand backbone methyl groups of the previously reported complex [CH{(Me)2CN-2,6-iPr2C6H3}2In] with trifluoromethyl substituents results in only minor modifications to the dimensions of the NCCCNIn metallacycle. The electronic structures of both indium species were interrogated by DFT calculations to reveal similar frontier molecular orbital schemes. In agreement with calculations performed previously on the aluminium and gallium complexes, [CH{(Me)2CN-2,6-iPr2C6H3}2Al] and [CH{(Me)2CN-2,6-iPr2C6H3}2Ga], the HOMO in both indium species comprises a metal-based sp-hybrid while the LUMO is a ligand-based orbital of pi symmetry. The vacant indium p-orbital is represented by the LUMO + 1. Although incorporation of the fluorinated substituents results in a stabilisation of the system overall, the stabilities and observed structural features of the complexes are reasoned to be primarily a result of the steric profile of the very bulky ligands and not through any redistribution of the electron density within the cyclic species. The thallium complex is isostructural to the analogous and previously reported aluminium, gallium and indium species. The greater stability of the monovalent state however is reflected in a reordering of the orbital energies and a stabilisation of the metal-based orbitals in the frontier region of the MO scheme.     

A simple oxidation procedure for biological material prior to analysis for mercury

The stability constants of aluminium(III), gallium(III), indium(III) and scandium(III) with 8-hydroxyquinoline and its 2-methyl derivative have been determined by potentiometric titration, with computation by the SCOGS program. In contrast to previous work, the results show that protonated species occur in several of the equilibria. The constants are discussed in terms of the nature of metal-to-ligand bonding in the complexes. X-ray photoelectron spectroscopy of the ligand coordinating atoms in the solid complexes confirms the significantly increased covalency of the gallium—oxygen bond compared to the same bond in the aluminium complex.     

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.