Laws of complex formation in a series of azo-substituted pyrocatechol derivatives and their tin(II) complexes

Physicochemical properties of new reagents, azo-substituted pyrocatechol derivatives and their tin(II) complexes, are studied. The acid-base properties of the hydroxy groups (pK′_i, pK″_i), parameters of complex formation reactions (pH, temperature, time), and instability constants of the complexes formed (pK _i) are determined. Quantitative correlations between the dissociation constants (pK′_a) of the functional analytical group, and the electronic Hammett constant σ for a substituent (pK′_a-pH₅₀ of the complex formation reaction), as well as between pK′_a and instability constants of the complexes (pK _a), are established. The quantitative correlations established allow the prediction of the physicochemical properties of the reagents and tin(II) complexes with new reagents of this class with the same functional analytical group (FAG) but other substituents.     

Beryllium(II) sorption from aqueous solutions by polystyrene-based chelating polymer sorbents

Optimal parameters of beryllium(II) sorption from aqueous solutions by polystyrene-based sorbents have been studied, namely: optimal sorption acidity (pH_opt), pH providing 50% sorption (pH₅₀), optimal time (τ, min) and temperature of quantitative sorption. The sorption capacities of the sorbents under study (SCSs) for beryllium(II) have also been determined; sorption isotherms have been constructed. The parameters determined for beryllium(II) sorption by chelating polymer sorbents (CPSs) make it possible to select the most efficient sorbent for practical use.     

A new procedure for determining copper in igneous rock and alloys

The influence of cationic surfactants, cetylpyridinium chloride (CPC), cetylpyridinium bromide (CPB), and cetyltrimethylammonium bromide (CTMAB), on the complexation of copper(II) with thenoyl-(2-oxopropyl)-N-(2-sulfo-4-nitro-5-oxyphenyl) azomethine (R) has been investigated. It has been found that monoligand compounds are formed at pH 4, while at pH 3 the formation of mixed-ligand compounds is observed. The detection limit for copper decreases and the stability constants of the complexes increase in the row Cu-R-CPC > Cu-R-CPB > Cu-R-CTMAB, with AN increase in the stability of the associates (Rh-CPC > R-CPB > R-CTMAB) in the complexation reaction. The ratio of components in monoligand (1: 1) and mixed-ligand (1: 1: 1) compounds has been determined. The limits of obedience to the Beer law have been found. A procedure has been developed for the photometric determination of copper in igneous rock and alloys.     

Sorption of phosphorus(V) by polymeric sorbents based on aminopolystyrene and 4-amino-<Emphasis Type="Italic">N</Emphasis>-azobenzenesulfamide

Phosphorus(V) sorption on sorbents based on aminopolystyrene and 4-amino-N-azobenzenesfulamide from aqueous solutions is studied. The following sorption parameters are determined: the optimum acidity, pH_opt; 50% sorption pH, pH₅₀; optimal time τ, min; quantitative-sorption temperature; and phosphorus(V) sorption capacity of the sorbent (SCS). Sorption isotherms are plotted.     

New correlation between metal-hydrolysis p<Emphasis Type="Italic">K</Emphasis> and sorbent-ionization p<Emphasis Type="Italic">K</Emphasis> for prediction of the pH of 50% metal-cation sorption on a chelating polymer sorbent

Metal sorption on chelating polymer sorbents (CPSs) is studied. A correlation is found between the 50%-sorption pH and the metal-hydrolysis pK, and pH₅₀ is predicted.     

Formation of mixed-ligand complexes in the complexing polymer sorbent-Pb<Superscript>2+</Superscript>-dinitrophenol systems

The complexation of lead(II) with a group of synthesized sorbents based on aminopolystyrene and substituted phenols having structurally different substituents of various electronic natures in the para position with respect to phenolic hydroxyl was studied. As third components, α-dinitrophenol and γ-dinitrophenol were examined. The following most important parameters of sorption were determined: the optimum pH value of quantitative sorption (pH_opt), the recovery (R, %), the sorption capacity of the sorbent (SCS_Pb, mg/g), the half-sorption pH value (pH₅₀), and the temperature and time (τ) of sorption in the presence of a third component. The structure of the mixed-ligand complex was determined.     

Change in the Space Potential in Glow Discharge Plasma during the Motion of the Shock Wave

Technical Physics - It has been established in experiments on the interaction of a shock wave with a glow discharge that the motion of the shock wave is accompanied by an increase in the potential...