2,3-Pyridinediol as a specific reagent for the detection of iron

Summary Iron complexation with 2,3-pyridinediol is used to detect iron specifically in presence of common ions present in the scheme of qualitative analysis. The method finds use in detection of iron in alloys, salts and medicinal preparations.

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Zusammenfassung Die Komplexbildung des Eisens mit 2,3-Pyridindiol wurde für den spezifischen Nachweis dieses Elements in Gegenwart üblicher Ionen im Analysengang verwendet. Dieser Nachweis wurde in Legierungen, in Salzen und in pharmazeutischen Präparaten durchgeführt.

     

Uniqueness of maximum pressure for the cubic form-function in the general theory of composite charges

In the present paper we have established uniqueness of maximum pressure for composite charges, when each component charge has the cubic form-function. The conditions for the occurrence of maximum pressure in or at the end of any stage have been explicitly obtained.     

A tracer study of the Liesegang rings

Summary The formation ofLiesegang rings in strontium phosphate precipitating in agar-agar gel medium was studied employing Sr⁹⁰ and P³² as tracers. Results show a periodic variation in the concentrations of the reacting ions, while the maxima of Sr⁺⁺ coincide with the precipitate bands and its minima with the interband clear spaces, it is the reverse for the PO₄ ^–––. A mechanism is proposed for the periodic precipitation based on the difference in the diffusion rates of the two reacting ions which makes the precipitate selectively permeable to the faster ion.

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Zusammenfassung Die Bildung vonLiesegang-Hingen bei Fällung von Strontiumphosphat in Agar-Agar wurde unter Verwendung von Strontium 90 und Strontium 32 als Tracer durchgeführt. Es zeigt sich eine periodische Variation der Konzentration der reagierenden Ionen. Die Maxima für Strontium fallen zusammen mit den Ringen, während die Minima im ungefähren Zwischenraum liegen. Das Umgekehrte ist für PO₄ ^––– der Fall. Als Mechanismus für die periodische Ausfällung ergibt sich eine Differenz in den Diffusionsgeschwindigkeiten der zwei reagierenden Ionen, derart, daß das Fällprodukt selektiv permeabler für das raschere Ion wird.

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This work was carried out in the Chemical Laboratories of the Banares University.     

Highly Productive Oxidative Biocatalysis in Continuous Flow by Enhancing the Aqueous Equilibrium Solubility of Oxygen

We report a simple, mild, and synthetically clean approach to accelerate the rate of enzymatic oxidation reactions by a factor of up to 100 when compared to conventional batch gas/liquid systems. Biocatalytic decomposition of H₂O₂ is used to produce a soluble source of O₂ directly in reaction media, thereby enabling the concentration of aqueous O₂ to be increased beyond equilibrium solubility under safe and practical conditions. To best exploit this method, a novel flow reactor was developed to maximize productivity (g product L^?1 h^?1). This scalable benchtop method provides a distinct advantage over conventional bio‐oxidation in that no pressurized gas or specialist equipment is employed. The method is general across different oxidase enzymes and compatible with a variety of functional groups. These results culminate in record space‐time yields for bio‐oxidation.     

N-benzamidosalicylaldimine complexes of copper(II), nickel(II), cobalt(II), iron(II), manganese(II), oxyvanadium(IV) and oxytitanium(IV)

Summary N-benzamidosalicylaldimine (H₂L) complexes of Cu^II, Ni^II, Co^II, Fe^II, Mn^II. VO_IV and TiO_IV have been prepared. The ligand probably coordinates to the metal from the hydroxyl, carbonyl and imino groups.     

Phase-Transfer Catalysis: Acylation of β-Dicarbonyl Compounds

The alkylation of β-dicarbonyl compounds under phase-transfer conditions has been studied in detail and, in virtually all of the reported examples, the C-alkylation products have been found to predominate.^1–6 Only when the reaction rate is slow is there any evidence for O-alkylation as, for example, when there is steric hindrance to the approach of the alkylating agent to the carbanionic centre.^1,7 There is no record, however, of the corresponding acylation reactions.     

THE MEDIUM EFFECTS IN THE SULPHONATION OF POLYCYCLIC AROMATIC HYDROCARBONS

Abstract

Both the relative reactivities and the initial isomer distributions in the sulphonation of polycyclic hydrocarbons were found to be strongly dependent on the composition of reaction medium.