Gravimetric determination of uranium(vi) with n-benzoylphenylhydroxylamine

Uranium(VI) can be quantitatively precipitated by N-benzoylphenylhydroxylamine at pH 5.4. The precipitate is weighed after ignition to U₃O₈, or directly as U0₂(C₁₃H₁₀O₂N)₂. Cerium(III). thorium, lead and bismuth can be masked with magnesium-EDTA complex. Iron(IlI), titanium (IV) zirconium and molybdenum(Vl) and small amounts of aluminium can be precipitated with the reagent and filtered before uranium(Vl) is determined in the filtrate by proper adjustment of acidity. Fluoride, carbonate and organic acids interfere.     

Complexometric determination of aluminium in iron ore,sinter, concentrates and agglomerates

A method for the complexometric determination of aluminium in iron ore, sinter, concentrates and agglomerates encountered in international trade is described. The sample is fused in a zirconium crucible with a mixed flux of sodium carbonate and sodium peroxide. The fused mass is completely soluble in hydrochloric acid. The R₂O₃ oxides are then precipitated with ammonia and redissolved in hydrochloric acid. Elements such as iron, titanium and zirconium are separated from aluminium by solvent extraction with cupferron and chloroform. After removal of traces of organic matter from the aqueous phase, the solution is treated with an excess of EDTA, which is then back-titrated with zinc solution (Xylenol Orange as indicator). Addition of ammonium fluoride then releases EDTA equivalent to the aluminium and this is titrated with zinc solution. The method is rapid. The precision and accuracy are excellent, and the results comparable with those obtained by the referee method.     

Gravimetric determination of beryllium with acetoacetanilide

Summary An organic reagent viz. acetoacetanilide has been found out which precipitates beryllium quantitiatively aboveph 5.5. The complex, Be(C₁₂H₁₀O₂N)₂, containing 2.49% Be can be weighed directly after drying. Beryllium can be precipitated from solutions containing aluminium and iron by masking these foreign elements with EDTA. A method has also been described for the determination of beryllium content in beryl.

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Zusammenfassung Beryllium kann oberhalbph 5,5 mit Acetoacetanilid quantitativ gefällt werden. Der gebildete Komplex, Be(C₁₀H₁₀O₂N)₂, der 2,49% Be enthält, kann gleich nach dem Trocknen gewogen werden. Die Gegenwart von Aluminium und Eisen stört nicht, wenn äDTA als Maskierungsmittel zugegeben wird. Die Bestimmung von Beryllium in Beryll wird ebenfalls beschrieben.

     

Estimation of palladium

Summary In presence of tartaric acid and ammonium chloride, quinaldinic acid quantitively precipitates palladium from a hot solution at a p_H range 3 to 7 whereas other ions such as arsenic (As³⁺ and As⁵⁺), mercury (Hg²⁺), cadmium, bismuth, antimony, iron, chromium, aluminium, beryllium, thorium, cerium (Ce³⁺), titanium, zirconium, uranium (UO₂ ²⁺), vanadate, molybdate, tungstate, cobalt, nickel, manganese, magnesium, calcium, barium and strontium remain in solution. The palladium complex is quite insoluble in hot water and can be dried at any temperature up to a maximum of 353° C when it decomposes.     

Analytical application of embelin

Summary Embelin is employed as a analytical reagent for the estimation of (a) aluminium in solutions of p_H 4.0–4.5 and (b) beryllium in solutions of p_H 6.5–7.0. While aluminium could be estimated both as its complex or as oxide, Al₂O₃, beryllium could be estimated only as oxide, BeO. The reagent is also employed for the separation of beryllium from aluminium.Part I: See Z. analyt. Chem. 175, 114 (1960).     

Compleximetric titrations of iron(III) and iron(II) with triethylenetetraminehexaacetic acid

The stability constants of the iron(II) complexes of TTHA (triethylenetetraminehexaacetic acid) were calculated from measured pH and redox potentials. The values of the cumulative constants obtained were: log β_FeL= 15.37, log β_FeHL = 23.83, log β_FeH2L = 28.0, log β_Fe2L = 24.73. On the basis of these values and the previously determined constants ofiron(III) complexes, the possibilities of titrating iron(III) and iron(II) with TTHA were investigated. Depending on the experimental conditions, either FeL or Fe₂L formed. Actual titrations were in agreement with the developed theory. The influence of aluminium and titanium on titrations of iron(III) solutions was elucidated.     

The determination of beryllium in geological and industrial materials by atomic-absorption spectrometry after cation-exchange separation

A method is described for the determination of beryllium in geological and industrial samples. After dissolution of the sample in mineral acids, beryllium is separated from the matrix elements by chloroform extraction of its acetylacetonate from a solution of pH 7 containing ascorbic acid and EDTA. Beryllium is separated from the organic extract and from co-extracted aluminium by means of a column of the strongly acidic cation-exchanger Dowex 50; beryllium is adsorbed from a medium consisting of 60 % (v/v) tetrahydrofuran, 30 % (v/v) chloroform and 10 % (v/v) methanol containing hydrochloric acid, aluminium is removed with 0.4 M oxalic acid and after elution with 6 M hydrochloric acid, beryllium is determined by atomic-absorption spectrometry with a nitrous oxide-acetylene flame. The method was used to determine p.p.m. and sub-p.p.m. quantities of beryllium in geochemical reference materials, U₃O₃ and yellow cake samples, and manganese nodules.     

Analytical applications of condensed phosphoric acid-II: determination of aluminium, iron and titanium in bauxites after decomposition with condensed phosphoric acid

Bauxites can be decomposed by condensed phosphoric acid (CPA) very rapidly without the need for subsequent manipulations such as elimination of silica, digestion of fused products and filtration. It is best to heat the samples at about 700 degrees prior to the decomposition, to prevent them from floating on the surface of the CPA. Under the proposed conditions (100 mg of sample, 10 g of CPA, heating at 300 degrees for 30 min), aluminium, iron and titanium are dissolved quantitatively. Iron is determined by photometry with 1,10-phenanthroline after solvent extraction with MIBK, while titanium is determined with N-benzoyl-N-phenylhydroxylamine (BPHA). The effect of phosphate on the determination of titanium is reduced to a minimum at a BPHA concentration of 0.3% and a hydrochloric acid concentration of 7.2M. Aluminium and iron are precipitated quantitatively as the oxinates at pH 5.5 in the presence of orthophosphoric acid or hydrolysed CPA, while the precipitation of titanium oxinate is completely suppressed by the addition of hydrogen peroxide. The total amount of aluminium and iron is obtained by determining the amount of oxine by bromination method. The amount of aluminium is obtained by subtracting the amount of iron from the sum of the two.     

Influence of aluminium precursor on physico-chemical properties of aluminium hydroxides and oxides

An attempt to obtain aluminium hydroxide that could give aluminium oxides of increased thermal stability was made. Aluminium hydroxide was precipitated during a hydrolysis of aluminium chloride in ammonia medium. The influence of preparative conditions, such as a dosing rate of aluminium precursor, pH, duration of the precipitate refluxing and temperature of calcination, on the properties of obtained hydroxides and oxides was investigated. The materials were studied with the following methods: thermal analysis, IR spectroscopy, low-temperature nitrogen adsorption and adsorption–desorption of benzene vapours. Precipitated boehmites had high values of S _BET determined from nitrogen adsorption (220–300 m²g^–1), good sorption capacity for benzene vapours, developed mesoporous structure and hydrophilic character. It has been proved that a high pH value during the precipitation of aluminium hydroxide favoured better crystallisation of boehmite structure, higher temperature of its dehydroxylation into γ-Al₂O₃, and delayed transformation of γ phase into α-Al₂O₃. Aluminium oxides derived from the hydroxides precipitated at a high pH were the most stable at high temperatures, and were characterised with the best surface properties. The online version of the original article can be found at     

Die D-Weinsäure als Reagens für quantitative Bestimmungen auf polarimetrischem Weg

Zusammenfassung Neue, quantitative Bestimmungsmöglichkeiten von Beryllium und Titan werden beschrieben, die auf dem linearen Drehwertanstieg der D-Weinsäure nach Zugabe steigender Ionenmengen beruhen. Treten Störungen durch andere Elemente auf, so werden Beryllium und Titan als Hydroxid gefällt, in Salzsäure gelöst und auf polarimetrischem Weg bestimmt. Es gelingt so die Bestimmung der beiden Elemente neben Magnesium, Aluminium, Eisen, Nickel, Kobalt und Kupfer. Die Methode ist rasch und einfach. Auf eine Möglichkeit, Beryllium neben Titan und Uran zu bestimmen, wird hingewiesen. Ferner wird die Titanbestimmung in einer Aluminiumlegierung beschrieben.

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Summary New quantitative possibilities of determining beryllium and titanium are described; they are based on the linear rotational rise of D-tartaric acid after addition of increasing quantities of these ions. If interferences arise because of other elements, beryllium and titanium are precipitated as hydroxide, dissolved in hydrochloric acid, and determined polarimetrically. The two elements were successfully determined in this way in the presence of magnesium, aluminium, iron, nickel, cobalt and copper. The method is rapid and simple. A possibility of determining beryllium in the presence of titanium and uranium was noted. In addition, the determination of titanium in an aluminium alloy is described.

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Résumé On décrit de nouvelles possibilités de dosage quantitatif du béryllium et du titane, reposant sur l'augmentation linéaire du pouvoir rotatoire de l'acide tartriqued après addition de quantités d'ions croissantes. D'autres éléments gênent, aussi on précipite le béryllium et le titane à l'état d'hydroxydes, on dissout dans l'acide chlorhydrique et l'on dose par voie polarimétrique. De cette manière, le dosage des deux éléments est correct en présence de magnésium, aluminium, fer, nickel, cobalt et cuivre. La méthode est rapide et simple. On indique une possibilité de doser le béryllium en présence de titane et d'uranium. On décrit, de plus, le dosage du titane dans un alliage d'aluminium.

     

Gravimetric determination of tungsten(vi) with n-benzoyl-n-phenylhydroxylamine

Tungsten can be quantitatively precipitated with N-benzoylphenyl-N-hydroxylamine in presence of hydrochloric acid (0.5–1 N). The precipitate can be weighted as WO₂(C₁₃H₁₀O₂N)₂ or WO₃. Molybdenum, vanadium, titanium, and iron can be separated by prior precipitation of these mutais with the above reagent in presence of tartrate ions; tungsten is then determined in tlie filtrate. L'ranium does not interfere, but chromium (VI), fluoride and phosphate do.     

1-(o-Carboxyphenyl)-3-hydroxy-3-phenyltriazene,a new reagent for the direct gravimetric determination of titanium(IV)

A direct gravimetric method for the determination of titanium with a new reagent, 1-(o-carboxyphenyl)-3-hydroxy-3-phenyltriazene, is proposed. The titanium is precipitated at the pH range 2.0–5.0 and weighed as TiO(C₁₃H₁₀N₃O₃)₂ after drying at 115–120°. In the presence of EDTA, only niobium and tantalum interfere.     

Strukturbestimmung eines aluminium- und berylliumhaltigen tetragonalen Bors der Formel AIBe0,8B24,2

Structural determination of tetragonal boron containing aluminium and beryllium with the formula AlBe_0.8B_24.2 The boron atoms in the lattice of AlBe_0.8B_24.2 (～AlBeB₂₄) are found on the same places as in the lattice of tetragonal boron-I, with only small changes of the parameters. Obviously the beryllium atoms are distributed statistically on such boron places, which belong to the B₁₂-icosahedrons. The aluminium atoms are in holes, which are surrounded by a tetrahedron of four icosahedrons, with small displacements from the hole center towards increased or decreased z-parameter.     

Polyethylene powder as an absorbent for preconcentration of aluminium, beryllium and thallium

Polyethylene powder has been shown to function effectively as an adsorbent for the preconcentration of complexing agents and their metal complexes. The adsorbed trace compound can easily be eluted from the polyethylene by use of polar organic solvents and subsequently be determined by AAS or spectrophotometry. In this paper, the adsorptivity of chrome azurol S and rhodamine B and their complexes with aluminium, beryllium and thallium (as [Tl Br₄]^–) on polyethylene was investigated. The influence of the pH and the effect of the saline concentration of the solution were studied. From the preconcentration of aluminium and beryllium with chrome azurol S, enrichment factors up to 10 and 20, respectively, could be achieved. For thallium with rhodamine B the factor was 50. With this analytical procedure, recoveries of 92–110%, 94–103% and 96–104% with relative standard deviations of 3.4–5.4%, 2.6–5.3 and 1.6–7.2% for aluminium, beryllium and thallium respectively, were achieved. The method was used for the preconcentration of trace amounts of the metals from tap water, dialysis solutions and solid salts.     

Simultaneous determination of aluminium,aluminium fluoride complexes and iron in groundwater samples by new HPLC–UVVIS method

The paper presents the application of the new HPLC–UVVIS method used in speciation analysis of aluminium form Al³⁺, aluminium complexes with fluorides and iron in groundwater samples. Based on the obtained results of groundwater samples analysis, the separation of iron in the retention time ≈ 3.7, was obtained. The conditions of the occurrence of particular aluminium forms based on the speciation analysis and modeling in the Mineql program were presented and confirmed. The influence of pH and ligand concentration on forming complexes was shown. The preliminary study of aluminium complexes with sulfates based on model solutions did not allow for the separation of the above complexes in presented analytical system. The paper presents the possible types of transformation of aluminium hydroxy forms and aluminium sulfate complexes by the reaction of the sample with mobile phase. An indirect method for the determination of aluminium in the form of aluminium sulfate was proposed. The new method was successfully applied in the determination of the following aluminium forms: Al³⁺, AlF₂⁺, AlF₃⁰, AlF₄^?, AlF²⁺ and Fe³⁺.     

Anion exchange studies of aluminium and iron(III) in malonate solutions: Separation from mixtures

Summary Systematic anion exchange studies of aluminium and iron(III) in malonate solutions were carried out. Aluminium and iron form negatively charged complexes with malonic acid at pH 4.5. The malonate complexes can be adsorbed on a column (1.4×20 cm) of Dowex 21K. Various reagents (hydrochloric, sulfuric and nitric acids; ammonium chloride, bromide, sulfate and nitrate; and sodium chloride and nitrate) were tested as eluants. The efficiency of the eluants was evaluated in terms of elution constant, volume distribution coefficient and peak elution volume. Methods were developed for the separation of aluminium or iron from a large number of elements by taking advantage of the fact that certain elements form weaker or stronger malonate complexes as compared to those of aluminium or iron. The method was applied to the analysis of aluminiumbased alloy.

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Zusammenfassung Systematische Untersuchungen des Verhaltens von Al(III) und Eisen(III) in Malonatlösungen gegenüber Anionenaustauschern wurden durchgeführt. Beide Metalle bilden mit Malonsäure negativ geladene Komplexe bei pH 4,5. Diese werden in einer Säule (1,4×20 cm) von Dowex 21K adsorbiert. Verschiedene Reagenzien (HCl, H₂SO₄, HNO₃; NH₄Cl, NH₄Br, (NH₄)₂SO₄, NH₄NO₃; NaCl und NaNO₃) wurden als Elutionsmittel geprüft. Deren Wirksamkeit wurde mit der Elutionskonstante, dem Verteilungskoeffizienten und der Peakhöhe des Elutionsvolumens gekennzeichnet. Trennungsmethoden für Al oder Fe von vielen anderen Elementen ergaben sich daraus, daß manche Elemente vergleichsweise schwächere bzw. stärkere Malonatkomplexe bilden. Die Methode wurde zur Analyse von Aluminiumlegierungen verwendet.

     

Photochemistry of iron pentacarbonyl adsorbed on titanium dioxide

The photolysis of iron carbonyl (Fe(CO)₅) adsorbed on titanium dioxide (TiO₂, anatase) was studied by FT-IR spectroscopy. When adsorbed Fe(CO)₅ is illuminated by visible and near-UV light, the IR spectrum of its photolysis products is hardly observed, indicating that most of the Fe(CO)₅ is photodecomposed to iron(0) or iron oxides on TiO₂. The carbon monoxide (CO) evolution rate upon illumination depends on the wavelength of light; 433 nm light is more effective for CO evolution than 366 nm light. This result implies that the band-gap excitation of TiO₂ has little effect on the photolysis of adsorbed Fe(CO)₅, since the absorption edge of TiO₂ (anatase) lies at around 400 nm. The effects of substrates on the photolysis of adsorbed Fe(CO)₅ are discussed with reference to previous results obtained for aluminium oxide (Al₂O₃) and silicon dioxide (SiO₂), on which the photolysis leads to the formation of Fe₂(CO)₉ or Fe₃(CO)₁₂.     

The separation of beryllium from polyvalent cations with a diallyl phosphate complexing resin

The complexing polymer sodium diallyl phosphate (NaDAP) when used in conjunction with disodium ethylene diamine tetraacetate (Na₂EDTA) separates beryllium quantitatively from alkaline earths (Ca and Sr), ferric and divalent cations of the first transitional period, aluminium and lanthanides, cadmium and mercury(II), bismuth and polonium(IV). The high affinity of NaDAP for beryllium should permit its concentration by several orders of magnitude, when present as a minor or trace component in a mixture of polyvalent cations. The results are compared with those obtained using sulphonated resin.