Saswati P. Bag

Solvent extraction and photometric determination of molybdenum (VI) with 2-aminobenzenethiol.

A new extractive photometric method is described for estimation of molybdenum with 2-aminobenzenethiol. The green complex in chloroform has its absorbance maximum at 700 nm and is stable for 2 hr when extracted from a solution of optimum pH range 1.4-2.8. The extraction is quantitative. The sensitivity is 0.0075 microg cm (2). Beers law is obeyed over the range 0.25-10 ppm with optimum range 0.5-4.5 ppm. The molar absorptivity is 7.08 x 10(4) 1.mole(-1). cm(-1). The overall stability constant is 2.0 x 10(8) at 25 +/- 0.1 degrees.

Extraction of vanadium(V) chelates with N-benzohydroxamic acid (BHA) and ammonium thiocyanate and its application in steel and rock analyses

A mixed-ligand complex of vanadium(V) with N-benzohydroxamic acid and thiocyanate formed at various acidities can be extracted into methyl isobutyl ketone, and used for photometric determination of trace amounts of vanadium in materials such as alloy steels and rocks. The absorption maximum of the violet mixed-ligand complex is at 535 nm. The values for the simple complex are 505 nm and molar absorptivity 7.4 x 10(3)l.mole(-1).cm(-1).

Determination of trace organic dicarboxylic acids and amines by ion-chromatography.

Retention times for various species in separator columns packed with Zipax SAX, Vydac SC, and MicroPak AX-10 anion-exchange resins were compared with those obtained with Dionex separator column for anions. The MicroPak column was found to separate organic dicarboxylic acids, and the logarithm of the retention time of the acids of a homologous series was found to bear a simple relationship to the number of methylene groups between the carboxylic groups. A modified column system, consisting of a post-separator column packed with Vydac CX cation-exchange resin placed between a Dionex separator column for cations and a suppressor column, was able to separate a nine-component mixture of Na(+), K(+), NH(4)(+), methylamine, ethylamine, propylamine, butylamine, dimethylamine and trimethylamine, a separation that is not possible with any other current column system.

Spectrophotometric estimation of molybdenum with disodiom cis-1,2-dicyanoetfaylene-1,2-dithiolate

A rapid spectrophotometnc method is described for estimation of molybdenum by use of the molybdenum-dicyanoethytene dithiolate complex. The bright green complex has its absorption maximum at 665 nm and in 50% aqueous acetonitrilc is stable for several days at 3M hydrochloric add concentration, The estimation is more sélective if longer wavelengths and high acidity are used. Beers law is obeyed over the range 1-16 ppm molybdenum, optimum range 4-16 ppm. The overall formation constant Of the complex with metal to ligand ratio of 1:4 is 5 +/- 2 x 10(18). The molar absorptivity is 5.05 x 10(3) l.mole(-1).cm(-1).

Determination of trace amounts of vanadium: A ternary extraction and photometric method using N-salicylhydroxamic acid and thiocyanate

SummaryA new extractive photometric method has been developed for a binary complex of vanadium(V) with salicylhydroxamic acid, a bluish-violet complex at pH 3.0 and a violet ternary complex system with ammonium thiocyanate at pH 0.95, both complex species being extractable into methylisobutylketone. The violet complex absorbs at 540 nm and is stable up to 48 hr at 23–25°. The sensitivity is 0.0061μg V(V) cm−2. The method has been applied for the analysis of ores and alloy steels containing vanadium.ZusammenfassungVanadin (V) bildet mit Salicylhydroxamsäure einen binären, blauvioletten Komplex bei pH 3,0 und einen ternären, violetten Komplex mit Ammoniumrhodanid bei pH 0,95. Beide Komplexverbindungen sind mit Methylisobutylketon extrahierbar. Die violette Komplexverbindung hat bei 540 nm ihr Absorptionsmaximum und ist bei 23–25° C bis zu 48 Stunden stabil. Die Empfindlichkeit der Reaktion beträgt 0,0061μg V(V)·cm−2. Die Reaktion wurde für die Analyse von Erzen und Stahllegierungen verwendet.

Spectrophotometric determination of iron with chelidamic acid

SummaryChelidamic acid forms with iron a complex at pH 5.8 to 8.5 having the maximum absorption at 460 nm. The metal to reagent ratio is 1∶3 and the instability constant is about 8.21 · 10−15. The complex obeys Beers law from 0.4 to 16 ppm of iron and the optimum concentration range is 1 to 8 ppm, with a relative analysis error of 2.3% per 1% absolute photometric error.ZusammenfassungChelidamsäure bildet mit Eisen beiph 5,8–8,5 einen Komplex, der bei 460 nm ein Absorptionsmaximum aufweist. Das Verhältnis Metall: Reagens beträgt 1∶3, die Instabilitätskonstante etwa 8,21 · 10−15 Das Beersche Gesetz wird im Bereich von 0,4–16 ppm befolgt, der optimale Konzentrationsbereich liegt bei 1–8 ppm. Der relative Fehler beträgt 2,3% je 1% absoluten photometrischen Fehler.

Spectrophotometric investigation of Ti(IV) complexes of N-phenylacetylphenylhydroxylamine☆

Abstract N-Phenylacetylphenylhydroxylamine complexes of titanium(IV), yellow in color and extractable into chloroform, with metal:ligand ratios 1:2, 1:3, and 1:4, exist in the acidity ranges of 1–3, 4–7, and 7.5–9.0 N HCl, respectively. The compositions of the complexes were found out by Jobs and molar ratio methods. The stepwise and overall formation constants were evaluated following extensions of Yatsimirskiis, Ledens and Harvey and Mannings methods. A computer was used for evaluation of the formation constants of the 1:3 system following the first method. A spectrophotometric method based on solvent extraction technique, for determination of trace amounts of titanium in the presence of diverse ions, has also been described.

Gravimetric determination of palladium with quinolinimide as a reagent

SummaryQuinolinimide which is found to be a selective reagent for palladium forms a complex of the composition Pd(C7H3O2N2)2. The reagent quantitatively precipitates palladium from solutions of pH 0.5 to 2.5 in presence of common ions as well as platinium metals, except tin which, however, can be kept in solution by complexing with citric acid. The palladium complex being stable up to 307° C can be directly weighed.ZusammenfassungChinolinimid wird als selektives Reagens für Palladium vorgeschlagen. Bei pH-Werten zwischen 0,5 und 2,5 kann Palladium quantitativ in Form des Komplexes Pd(C7H3O2N2)2 gefällt werden, wobei die meisten anderen Ionen, auch die der Platinmetalle, in Lösung bleiben. Zinn stört, kann aber mit Citronensäure maskiert werden. Der Palladiumkomplex ist bis 307° C stabil und kann direkt ausgewogen werden.

Quinolinic acid as a reagent for the gravimetric and volumetric estimation of palladium

Summaryβ-Aminopicolinic acid has been used successfully as a very selective reagent for the precipitation of palladium as Pd(C6H5O2N2)2 from solutions 1.0 normal with respect to hydrochloric acid as well from solutions where the pH is 12.5, covering almost the whole pH range. Ions of all the common elements and the platinum metals, except copper, do not interfere. The influence of copper is easily eliminated by masking it with EDTA.A useful and rapid method for the estimation of palladium volumetrically based on the solubility of palladium aminopicolinate complex in potassium cyanide solution has been described.

Hydroxamic acid dinuclear complexes of molybdenum(V) and molybdenum(III)

SummaryMolybdenum(V) and molybdenum(III) complexes [Mo2O3L4] and [Mo2L6] derived from hydroxamic acids (HL) were prepared and identified by Raman, i.r., e.s.r., electronic spectra and analytical data. The low magnetic moments of the dinuclear complexes are due to in part to intramolecular interactions. Electronic spectra and vibrational studies indicate the presence of a Mo2O3 core in the molybdenum(V) complexes. The relative intensities of the, main and satellite peaks in e.s.r. spectra indicate the dinulcear nature of molybdenum(III) hydroxamates.