Paper chromatography in the separation of ions : Separation of silver,copper and arsenic group elements

A paper Chromatographic study ot the separability of ions of elements of the silver, copper and arsenic groups, using different solvents and a number of complexing agents, reveals that the solvents consisting of (1) acetone, hydrochloric or acetic acid (with or without ammonium iodide) and (2) tert. -butyl alcohol, hydrochloric or acetic acid, promote the complete separation of at ; least five elements present in microgram amounts in a mixture. Other complexing agents, such as thiourea, bismuthiol I, bismuthiol II and 2-mercaptobenzothiazole are not very useful in the separation of the ions. The R_I., R_T values and the sequences of separation are tabulated to show their behaviour.     

Spectrophotometric determination of nickel(II), palladium(II) and copper(II) in presence of each other and other ions with 1-(o-carboxyphenyl)-3-hydroxy-3-phenyltriazene

Summary 1-(o-Carboxyphenyl)-3-hydroxy-3-phenyltriazene was found to be an excellent spectrophotometric reagent for the determination of nickel(II), palladium(II) and copper(II). At pH 6.8–8.3, 2.4–3.5 and 2.2–3.8, nickel, palladium and copper form greenish yellow, yellowish orange and light green complexes with maximum absorption at 410, 410, 400 nm, respectively. The systems obey Beer's law with optimum ranges from 0.25 to 2.0 ppm for Ni(II), 0.5–4.0 for Pd(II) and 0.5–4.0 for Cu(II); the elements form 11 complexes with the instability constants 2.1×10^–5, 1.5×10^–5 and 2.0×10^–5, resepctively. Effects of other anions and cations on the colour systems have been studied and procedures for the determination of Ni(II), Pd(II) and Cu(II) in presence of each other are described.

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Spektrophotometrische Bestimmung von Nickel(II), Palladium(II) und Kupfer(II) nebeneinander und in Gegenwart anderer Ionen mit Hilfe von 1-(o-Carboxyphenyl)-3-hydroxy-3-phenyltriazen

Zusammenfassung Ni, Pd und Cu bilden mit dem Reagens bei pH 6,8–8,3, 2,4–3,5 bzw. 2,2–3,8 grünlich-gelbe, gelblich-orange bzw. hellgrüne Komplexe mit Absorptionsmaxima bei 410, 410 bzw. 400 nm. Das Beersche Gesetz wird in den Bereichen 0,25–2,0, 0,5–4,0 bzw. 0,5–4,0 ppm befolgt. Die Elemente bilden 11-Komplexe mit den Instabilitätskonstanten 2,1 · 10^–5, 1,5 · 10^–5 bzw. 2,0 · 10^–5. Der Einfluß anderer Kationen und Anionen wurde untersucht und Arbeitsvorschriften werden angegeben.

     

Spectrophotometric determination of iron with quinolinic acid

Quinolinic acid forms two complexes with ferrous ion. One is formed at pH 5.9 and has maximum absorption at 420 mμ; the metal to reagent ratio is 1:2 and the instability constant is about 7.10^-9. The other complex is formed with an excess of potassium cyanide and shows maximum absorption at 440 mμ; the metal to reagent ratio is 1:1 the instability constant is only 2.73?10^-5. The latter complex adheres to Beer's law from 1 to 16 p.p.m. of iron, and its optimum concentration range is 4^-16 p.p.m. of iron, where the percent relative error per 1% absolute photometric error is only 2.94.The reagent is highly specific and can be used spectrophotometrically for the determination of very small quantities of iron in presence of many cations.     

Tiron as a spectrophotometric reagent for the estimation of osmium

A method for the spectrophotometric determination of osmium with tiron as a reagent has been described. The reagent forms a soluble and stable coloured complex on heating with osmium in the presence of sodium acetate. The regions of maximum and minimum absorptions are at 470 mμ and 410 mμ, respectively, and the system obeys Beer's law from 2 to 32 p.p.m. of osmium. But the optimum range, with the relative analysis error of 2.878% per 1% absolute photometric error, is from 8 to 24 p.p.m. of osmium. The sensitivity of the reaction is 0.033 μg/cm² (SANDELL) and the molar extinction coefficient is 5706. In solution, the complex is formed when the osmium and the reagent are in a ratio of l : 1 ; it has an instability constant equal to approximately 5.57? 10^-5.     

Cation exchange behaviour of mercury (II) on Dowex 50W-X8

Summary Quantitative studies are reported on the behaviour of mercury at milligram level, using cation exchange resin Dowex 50W-X8. Various eluants such as nitric acid, hydrochloric acid, sulphuric acid, ammonium acetate, sodium nitrate solutions, sodium nitrate-nitric acid mixtures, ammonium acetate-acetic acid mixture are used for column operation. The elution constants are evaluated. Mercury(II) is separated from different cations, i.e., Ca²⁺, Ba²⁺, Sr²⁺, Mg²⁺, Fe³⁺, Al³⁺, Co²⁺, Ni²⁺, Zn²⁺, Cu²⁺ by selective elution.

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Zusammenfassung Das Verhalten von mg-Mengen Quecksilber am Kationenaustauscher Dowex 50W-X8 wird quantitativ untersucht. Dabei werden folgende Eluierungsmittel benutzt: Salpetersäure, Salzsäure, Schwefelsäure, Lösungen von Ammoniumacetat und Natriumnitrat sowie die Gemische Salpetersäure-Natriumnitrat und Essigsäure-Ammoniumacetat. Die Elutionskonstanten werden berechnet. Durch selektive Eluierung kann Quecksilber von mehreren Kationen (Ca²⁺, Ba²⁺, Sr²⁺, Mg²⁺, Fe³⁺, Al³⁺, Co²⁺, Ni²⁺, Zn²⁺, Cu²⁺) getrennt werden.

     

Synthesis of Pyrimidine Annelated Heterocycles [1]. Regioselective Heterocyclization of 6-Cyclopent-2-enyl-5-hydroxy-1,3-dimethyl-pyrimidine-2,4( 1H, 3H)-dione and 5-Cyclopent-2-enyl-6-hydroxy-1,3-dimethylpyrimidine-2,4( 1H, 3H)-dione

Two hitherto unreported pyrimidine annelated heterocycles were synthesized from 6-cyclopent-2-enyl-5-hydroxy-1,3-dimethylpyrimidine-2,4(1H,3H)-dione and 5-cyclopent-2-enyl-6-hydroxy-1,3-dimethylpyrimidine-2,4(1H,3H)-dione by reaction with pyridine hydrotribromide or hexamethylenetetramine hydrotribromide. The first one was also obtained by reaction with concentrated sulfuric acid.     

Paper chromatography in the separation of ions

A study has been made of the separation of ions of the alkali metals, alkaline earth metals, elements of groups IIIA and B and of anions, such as arscnate, phosphate, vanadate, molybdate, tungstate and chromate, with solvent mixtures of tert.-butyl alcohol, water and hydrochloric or acetic acid in the ratio of 7:2 1, and with 01 without tartaric, citric or malonic acid. The solvent mixture with hydrochloric acid as one of the components was found to be most effective for the separation of six cations or three anions from their mixtures. The rl and R1 values and the sequences of separations have been recorded     

Extraction and spectrophotometric determination of cobalt(ii) with 2-thenoyltrifluoroacetone

The rapid extraction and simultaneous spectrophotometric determination of mg amounts of cobalt(II) by means of 2-thenoyltrifluoroacetone is described. The yellow cobalt(II)-TTA chelate solution in acetone-benzene obeys Beer's law at 430 mμ over the range 12 to 51 μg of cobalt(II) per ml. At pH 5.1–6.8 a single extraction with 0.15 M TTA in acetone is satisfactory. The system is stable for 96 h. Silver, zirconium, strontium, thorium, zinc, lead(II) and mercury(II) do not interfere.