Solvent extraction of phosphonium salts and their analytical applications : Separation and spectrophotometric determination of hexacyanoferrate(III)

The potentiometric determination of zinc in chloride solutions with a coated wire electrode is described. The electroactive membrane contains the chlorozincate(II) salt of Aliquat 336S in poly (vinyl chloride). The electrode shows a useful response over the range 10^-5 M–10^-1 M zinc(II) in 3 M total chloride solutions in the pH range 1.5–6. The electrode is more responsive to the divalent tetrachlorozincate(II) than to the monovalent trichlorozincate(II) species. Applications in compleximetric titrations, and to the analysis of zinc oxide and zinc concentrates are reported.     

Solvent extraction studies of phosphonium salts and their analytical applications : Detection of gold. identification of gold and minor constituents in gold alloys

Gold is very efficiently extracted with benzene or toluene after precipitation in acidic solution by excess thiocyanate and triphenylisopropyl phosphonium ions. An almost specific test for gold is thus possible and large amounts of gold can be separated from other elements. A scheme of separation is described for the identification of gold and other metal components in gold alloys, based on selective extraction of the triphenylisopropyl phosphonium salts of the corresponding thiocyanato complexes.     

A spot test for the detection of periodate

Perrhenate is quantitatively extracted into methyl isobutyl ketone from aqueous solutions containing copper(II), azide and an excess of 2,2'-bipyridine. Measurement of the extracted copper either by spectrophotometry or by atomic absorption spectrometry, allows the determination of perrhenate in the ranges 16–40 μg ml⁻¹ or 3–16 μg ml⁻¹ in the final dilution, respectively. The procedure is highly selective, being applicable in the presence of a large concentration of molybdate and a considerable number of foreign ions. The extracted species corresponds to the formula CuN₃(bipy)₂ ReO₄.     

Solvent extraction studies of phosphonium salts and their analytical applications : Differentiation of n- and isopropyl halides

A test is described for identification and differentiation of n-propyl and isopropyl halides. The halide is reacted with triphenylphosphine to form the phosphoniun salt, and thiocyanate and copper or cobalt solutions are added, Extraction of the colored precipitate into a suitable solvent indicates n-propyl halide whereas isopropyl halides yield unextractable products. The test is applicable to solutions of each halide in the corresponding alcohol as well as to mixtures of both halides.     

Determination of germanium after extraction by methyl isobutyl ketone. II

Summary Germanium extracted by methyl isobutyl ketone from 7.5N hydrochloric acid solutions is made to react directly in the organic phase with phenylfluorone. Very stable colored solutions are obtained. The reaction is instantaneous and twice as sensitive as when carried out in aqueous medium with the same reagent. Optimum range of concentration for absorptiometric measurements was found to be 0.08 to 0.30g Ge/ml. Most of the interfering ions are separated by preliminary extraction of the cupferrates with the same ketone. W(VI) and Nb(V) are removed by previous extraction with excess thiocyanate in reducing medium making use of the same solvent. The procedure is applicable to the determination of germanium in coals.

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Zusammenfassung Germanium wird aus 7,5-n Salzsäure mit Methylisobutylketon extrahiert und unmittelbar in der organischen Phase mit Phenylfluoron umgesetzt. Die Reaktion erfolgt sofort, ist doppelt so empfindlich als in wäßriger Phase und führt zu sehr stabil gefärbten Lösungen. Die für Absorptionsmessungen am besten geeignete Konzentration liegt zwischen 0,08 und 0,30g Ge/ml. Die meisten störenden Ionen werden durch vorhergehende Extraktion ihrer Cupferonate mit demselben Keton entfernt. Wolfram(VI) und Niob(V) werden mit demselben Lösungsmittel in Gegenwart überschüssigen Rhodanids in reduzierendem Milieu abgetrennt. Das Verfahren eignet sich für die Bestimmung von Germanium in Kohle.

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Résumé On fait réagir directement le germanium avec la phénylfluorone, dans la phase organique, après son extraction par la méthylisobutylcétone de sa solution 7,5N chlorhydrique. On obtient ainsi des solutions colorées très stables. La réaction est instantanée et deux fois plus sensible que lorsqu'elle est effectuée en milieu aqueux avec le même réactif. Le domaine de concentration optimum pour les mesures absorptiométriques est situé entre 0,08 et 0,30g Ge/ml. La plupart des ions gênants sont séparés par une extraction préalable des cupferrates par la cétone. W(VI) et Nb(V) sont éliminés au cours d'une extraction préalable en présence d'un excès de thiocyanate en milieu réducteur et dans le même solvant. La technique est applicable à la détermination du germanium dans les charbons.

     

Solvent extraction studies of addition compounds of metal halides and triphenylphosphine, -arsine and -stibine : Part II. Spectrophotometric determination of palladium

Palladium extracted with a cyclohexane solution of triphenylarsine from weakly acidie medium containing excess iodide and sulfite, can be determined spectrophotometrically by measuring the; absorbance of the organic extract at 325 mμ. The optimum range of concentration was found to be 1 to 4 p.p.m. of palladium in the final dilution, Except for cyanide and large amounts of titanium(IV) and zirconium(IV), which inhibited the reaction, no other ion among the 41 tested interfered under the given conditions.     

A new analytical reaction for the determination of perrhenate

Perrhenate is quantitatively extracted into methyl isobutyl ketone from aqueous solutions containing copper(II), azide and an excess of 2,2'-bipyridine. Measurement of the extracted copper either by spectrophotometry or by atomic absorption spectrometry, allows the determination of perrhenate in the ranges 16–40 μg ml^?1 or 3–16 μg ml^?1 in the final dilution, respectively. The procedure is highly selective, being applicable in the presence of a large concentration of molybdate and a considerable number of foreign ions. The extracted species corresponds to the formula CuN₃(bipy)₂ ReO₄.     

A new reaction for the identification and determination of perchlorate : Part I. Detection of perchlorate

Perchlorate is extracted into methyl isobutyl ketone from aqueous solutions of copper(II) ions containing azide ions and an excess of 2,2'-dipyridyl. The yellow color of the organic phase can be used for the detection of perchlorate. A procedure is given which allows the identification of 3 μg of perchlorate. Considerably larger amounts of nitrate, chlorate, chloride and several other anions can be tolerated. By performing the test with the help of the Weisz ring oven technique, a limit of identification of 0.15 μg of perchlorate can be attained.     

Determination of germanium after extraction by Methyl Isobutyl Ketone. I

Summary The extractability of germanium from 7.5 N hydrochloric acid solutions by methyl isobutyl ketone has been studied and applied to the separation of small amounts of this element. The extracted germanium tetrachloride reacts with ammonium molybdate. The germanomolybdic acid formed dissolves in the organic phase where it is directly reduced with ascorbic acid. Very stable blue solutions are obtained. A number of interfering ions are separated by preliminary extraction of the cupferrates with the same solvent. Phosphate ions are removed by previous precipitation with zirconyl nitrate. Arsenate is reduced to arsenite and indirect interference of fluoride is avoided by addition of aluminum chloride. The extraction technique employed is very simple and the method is applicable to the determination of germanium in flue dusts and other complex silicon materials without previous separation of silicon.

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Zusammenfassung Die Extrahierbarkeit von Germanium aus 7,5-n Salzsäure mit Methylisobutylketon wurde untersucht und auf die Abtrennung kleiner Mengen dieses Elementes angewendet. Das extrahierte Germaniumtetrachlorid reagiert mit Ammoniummolybdat. Die entstehende Germaniummolybdänsäure löst sich in der organischen Phase und wird dort unmittelbar mit Ascorbinsäure reduziert. Man erhält hierbei sehr stabile blaue Lösungen. Eine Reihe störender Ionen wird durch vorhergehende Extraktion der Cupferronate mit dem gleichen Lösungsmittel entfernt. Phosphationen werden vorher mit Zirkonylnitrat ausgefällt. Arsenat wird zu Arsenit reduziert. Indirekte Störung durch Fluorid vermeidet man durch Zugabe von Aluminiumchlorid. Das angegebene Extraktionsverfahren ist sehr einfach und die Methode zur Bestimmung von Germanium in Flugstaub und anderen komplexen Siliciummaterialien ohne vorherige Abtrennung des Siliciums verwendbar.

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Résumé Etude de la possibilité d'extraction du germanium de solutions chlorhydriques acides 7,5 N par la méthylisobutylcétone et application à la séparation de petites quantités de cet élément. Le tétrachlorure de germanium ainsi extrait réagit sur le molybdate d'ammonium. L'acide germanomolybdique formé se dissout dans la phase organique dans laquelle il est directement réduit par l'acide ascorbique. On obtient des solutions bleues très stables. Un certain nombre d'ions gênants sont séparés par une extraction préalable de cupferronates dans le même solvant. Les ions phosphoriques sont éliminés par précipitation préalable par le nitrate de zirconyle. Les arséniates sont réduits en arsénites. La perturbation indirecte des fluorures est évitée par addition de chlorure d'aluminium. La technique d'extraction utilisée est très simple et la méthode est applicable à la détermination du germanium dans les poussières de foyers ou autres substances siliciées complexes sans séparation préalable du silicium.

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Presented in part at the national meeting of the Sociedade Brasileira para o Progresso da Ciência held in Curitiba, Brazil, November 1953.