Physicochemical properties of precursors of Al<Subscript>2</Subscript>O<Subscript>3</Subscript>–ZrO<Subscript>2</Subscript> oxide ceramics prepared by electrochemical method

Scanning electron microscopy, X-ray, and thermal analysis are used to examine the structure and properties of dispersive systems based on aluminum and zirconium oxides prepared electrochemically. The effect the conditions of synthesis have on the structure and morphology of Al₂O₃–ZrO₂ particles is studied. It is shown that the effect of an electric field on the reaction medium allows us to adjust the physicоchemical properties and morphology.     

Sorbents based on asbestos with a layer of an hydroxyethylcyclam derivative of PVC containing aquacomplexes of sulfuric acid or sodium hydroxide with aza-crown groups

Aquacomplexes of sulfuric acid and sodium hydroxide with aza-crown groups are synthesized in cavities of a sorbent from the porous layer of a PVC cyclam-derivative grafted onto fibers of asbestos fabric. The structure of sorbents with complexes is studied and their adsorption characteristics are determined. It is shown that the affinity of the developed surface toward ethanol, benzene, and hexane depends on the nature of complexes in the pore walls, and the volume of cavities formed as a result of the pores on the developed asbestos surface being coated with networks of aza-crown groups is larger than that of cavities with walls of aza-crown groups in the layers of a PVC cyclam derivative. Indicators of H⁺- and OH^–-conductivity of sorbents with complexes as electrochemical bridges are determined. It is shown that the major part of H⁺- and OH^–-ions moves through complexes with aza-crown groups in the region of cavities formed of pores on the surface of asbestos.     

Materials based on carbon-filled porous layers of PVC cyclam derivatives cross-linked with the surfaces of asbestos fabric fibers

The synthesis of bilayer materials with porous upper layers composed of PVC hydroxyethylcyclam derivatives filled with carbon and a layer consisting of hydroxyethylcyclam, cross-linked via Si–O–C groups with the silica chains of a developed surface of asbestos fabric, is described. The aza-crown groups in these materials are bound with aqua complexes of H₂SO₄ or NaOH. The structure of the materials is examined, their adsorption characteristics are determined, and the rate of motion of H⁺ or OH^– ions in electrochemical bridges is measured, while the formation of H₂ and O₂ in their cathodic and anodic polarization is determined as a function of voltage. It is shown that the upper layer of these materials is adsorption-active and electronand H⁺- or OH^–- conductive, while the bottom layer is only H⁺- or OH^–- conductive; through it, the upper layer is supplied with the H⁺ or OH^– ions needed for the regeneration of the aqua complexes broken down to H₂ and O₂ on carbon particles.     

The <Superscript>57</Superscript>Fe hyperfine interactions in the iron-bearing phases in some LL ordinary chondrites

The study of several LL ordinary chondrites such as NWA 6286 LL6, NWA 7857 LL6 and Chelyabinsk LL5 fragments with different lithology was carried out using scanning electron microscopy with energy dispersion spectroscopy, X-ray diffraction and ⁵⁷Fe Mössbauer spectroscopy with a high velocity resolution at 295 K. Small variations in the ⁵⁷Fe hyperfine parameters were revealed for the M1 and M2 sites in olivine, orthopyroxene and clinopyroxene as well as for α-Fe(Ni, Co), α ₂-Fe(Ni, Co) and γ-Fe(Ni, Co) phases, and for troilite in different samples of studied LL ordinary chondrites.     

A new triterpenic alcohol from Fomitopsis pinicola

From a biologically active fraction of extract from the fungus Fomitopsis pinicola, a new lanostane triterpene was isolated, 3alpha-acetyloxylanosta-8,24-diene-21-ol (1), along with two known triterpenic acids, (2) and (3). The structures of the compounds were elucidated based on their spectral properties. [structure: see text]     

Hydrolysis of magnesium hydride in the presence of ammonium salts

The influence of the nature of ammonium salts (NH₄Cl, (NH₄)₂SO₄, (NH₄)HSO₄, [(CH₃)NH₃]Cl) and their concentration in aqueous solutions on the hydrolysis of magnesium hydride has been studied. The highest degree and fastest rate of hydrolysis are observed at an ammonium salt concentration of ～7.5%. The most efficient activator among the ammonium salts under consideration is (NH₄)HSO₄.     

Atomic-absorption spectrometric determination of catalytic components (Pd,Ti, and Cu) in mixtures based on phenol

Procedures for the determination of palladium, titanium, and copper in organic reaction mixtures based on phenol were developed with the use of atomic absorption spectrometry and various sample preparation techniques: quantitative back extraction of the metals with a 2 M HCl solution; autoclave digestion in an acid mixture of HClO₄, HF, and HNO₃; and decomposition in a muffle furnace. The accuracy of analysis was demonstrated by a comparison between the results of the atomic-absorption spectrometric determination of the elements obtained with the use of all of the sample preparation techniques proposed and the standard addition method. The relative standard deviation in the determination of palladium, copper, and titanium was 7–10%.     

Reaction of indoles with ethyl bromopropynoate over Al<Subscript>2</Subscript>O<Subscript>3</Subscript> surface

1H-Indole and 2-methyl-1H-indole reacted with ethyl 3-bromopropynoate over aluminum oxide to give mixtures of the corresponding ethyl 3-(1H-indol-3-yl)propynoates and ethyl 3,3-bis(1H-indol-3-yl)-acrylates, the latter prevailing.