General Base Catalysis by Organic Bases of the Reaction of Diphenylphosphinic Hydrazide with Phenyl Isocyanate in Benzene

The kinetics of the reaction of diphenylphosphinic hydrazide with phenyl isocyanate in the presence of organic bases in benzene at 25°C were studied. The catalytic activity of the bases correlates with spectroscopic and thermodynamic Taft (pK _{H B}), Koppel-Palm (B), and Gutmann (DN) parameters. A common general base mechanism of the catalysis of semicarbazide formation by bases belonging to different classes of organic compounds is offered and discussed.     

Sorption behavior of 85Sr onto manganese oxides with tunnel structure

Journal of Radioanalytical and Nuclear Chemistry - Sorption behavior of strontium ions on manganese oxides obtained by sol–gel technique reduction of KMnO4 by different reagents (H2O2, MnCl2...     

Sorption of stable and radioactive Cs(I), Sr(II), Co(II) ions on Ti–Ca–Mg phosphates

Journal of Radioanalytical and Nuclear Chemistry - In this paper, we studied the features of stable and radioactive Cs(I), Sr(II) and Co(II) ions sorption on Ti–Ca–Mg phosphates. The...     

Adsorption properties of manganese oxides prepared in aqueous-ethanol medium toward Sr(II) ions

Journal of Radioanalytical and Nuclear Chemistry - In this study, nanostructured manganese oxides were synthesized using sol–gel method by reduction of KMnO4 with ethyl alcohol. Firstly, the...     

Effect of quartz substrate on adsorption and texture properties of titanium-containing silica membranes

Sol-gel method with joint hydrolysis of silicon and titanium alkoxides were used to synthesize titanium-containing silica membranes on a macroporous quartz substrate. Isotherms of low-temperature adsorption-desorption of nitrogen by the samples obtained were measured. Characteristic features inherent in mesoporous samples were found in the isotherms. A change in the adsorption properties of the membranes was observed upon a preliminary treatment of the substrate with a mixture of hydrogen peroxide and concentrated sulfuric acid.     

Physicochemical properties of manganese oxides obtained via the sol–gel method: The reduction of potassium permanganate by polyvinyl alcohol

Experimental data on the sol–gel synthesis of manganese oxides formed during the reduction of potassium permanganate by polyvinyl alcohol in an aqueous medium are presented. The physicochemical properties of the obtained manganese oxide systems that depend on the conditions of the synthesis are studied by means of DTA, XRD, SEM, and the low temperature adsorption–desorption of nitrogen. It is found that the obtained samples have a mesoporous structure and predominantly consist of double potassium–manganese oxide K₂Mn₄O₈ with a tunnel structure and impurities of oxides such as α-MnO₂, MnO, α-Mn₂O₃, and Mn₅O₈. It is shown that the proposed method of synthesis allows us to regulate the size and volume of mesopores and, to a lesser extent, the texture of the obtained oxides, which can be considered promising sorbents for the selective extraction of strontium and cesium ions from multicomponent aqueous solutions.     

Copper-magnesium oxide catalyst based on modified dolomite

Novel highly active copper-magnesium oxide catalysts based on modified dolomite were synthesized. They are of superior performance in comparison with catalyst materials (MTM, Birm, Pyrolox, MZHF) which are widely used currently in purification of water from iron. The influence of the nature of the copper precursor and concentration of impregnation solutions on the activity and phase composition of catalysts was found.