Vol 92, No 10 (2019)

Along with large-scale studies of promising electrode materials for lithium-ion and sodium-ion batteries, in the past 10–15 years there has been interest in rechargeable batteries with magnesium anode and in magnesium-ion batteries. Bismuth shows promise as a material for the negative electrode of magnesium-ion batteries. The review summarizes the data on the thermodynamic properties of magnesium-bismuth alloys and on possible use of bismuth or bismuth alloys in magnesium-ion batteries.

Water-soluble polymeric complexones, N-vinylpyrrolidone-N-allyl-p-aminosalicylic acid copolymers with low content of chelating units, were synthesized. The formation of Eu³⁺ heteroligand complexes containing these complexones was studied. The complexation of Eu³⁺ with the polymeric complexone and low-molecular-mass organic coligand, thenoyltrifluoroacetone (TTA), ensures efficient energy transfer from molecular orbitals of the polymeric ligand to Eu³⁺, allowing the Eu³⁺ luminescence intensity in aqueous solutions to be enhanced by more than 1–1.5 orders of magnitude. The maximal intensity of the Eu³⁺ luminescence in the heteroligand complex is observed at the [Eu³⁺]:[COO⁻] ratio of ∼1 and [Eu³⁺]/[TTA] = 1.2−1.5. In the presence of univalent metal salts, the Eu³⁺ luminescence intensity does not noticeably change up to their concentration of 0.4 M. Addition of Ca²⁺ or Mg²⁺ salts leads to a drastic decrease in the Eu³⁺ luminescence intensity in the solution.

Methods of X-ray diffraction analysis, impedance spectroscopy, and scanning electron microscopy were used to examine how thermal treatment modes affect the transport properties and microstructure of a lithium-conducting oxide ceramic of composition Li_0.33La_0.56TiO₃, produced from powders synthesized by the sol-gel method. It was found that the cubic structure of Li_0.33La_0.56TiO₃ can be stabilized as a result of quenching after the high-temperature of sintering at 1150°C. The conditions were determined in which Li_0.33La_0.56TiO₃ ceramic samples can be obtained with bulk ion conductivity of ∼1 × 10⁻³ S cm⁻¹ at 20°C, which corresponds to the maximum values for the ceramic based on lithium-lanthanum titanate.

The charge for the iron-potassium oxide system containing powdered cellulose was prepared by the sol-gel procedure and coprecipitation of salts. The influence of the charge preparation procedure, introduction of powdered cellulose, and its amount on the phase formation in the system [Fe₂O₃: K₂O: MoO₃: CeO₂: CaO: TiO₂: MgO: SiO₂]: powdered cellulose = (100 − x) [56.71: 20.88: 11.55: 6.38: 3.68: 0.58: 0.11: 0.11]: x, where x = 0–3 wt %, on the phase formation in the system in the temperature interval 25–1200°C was studied by differential calorimetry and by thermal and X-ray diffraction analysis. The influence of the sintering conditions, introduction of powdered cellulose, and its amount on the textural characteristics of the iron-potassium oxide material was examined. The activation energies of the transformation of maghemite to hematite in the samples were calculated. The contribution of the energy released in thermal degradation of powdered cellulose to the total amount of energy was estimated. Samples of the iron-potassium oxide material with the preset phase composition and textural characteristics required for further studies of the catalytic activity were prepared.

Effect of mixed Mg–Al oxides contained in catalysts on the distribution of target products formed in cracking of a mixture of vacuum gas oil with sunflower oil was examined. It was found that the process of deoxygenation of oxygen-containing compounds can be controlled by varying the molar ratio between magnesium and aluminum in the mixed oxides. For catalyst samples containing mixed oxides with large Mg: Al molar ratios, the content of carbon dioxide in inorganic products grows, which is indicative of the increased activity of the decarboxylation reaction. In addition, the results of catalytic tests demonstrate that the highest conversion and yield of the benzine fraction are observed for catalyst samples containing mixed oxides with small magnesium-to-aluminum ratios of 0.32: 1 and 0.49: 1. A high activity of hydrogen-transfer reactions is observed for these samples, which leads to a decrease in the yield of light olefins. Thus, it is advisable, for obtaining an increased yield of C₃ and C₄ olefins, to include into the composition of the catalysts mixed oxides with increased content of magnesium, with Mg: Al ratios of 1.90: 1 and more.

The intensification of mixing processes is considered when dissolving solid granular alkali (caustic soda) in hydrazine hydrate by applying the method of resonance-pulsating action to mix the reacting mass. The results of experimental studies are described, on the basis of which a method for calculating the process of dissolution of alkali in hydrazine hydrate is developed. The method allows estimating the mass transfer coefficient. The obtained results are consistent with published data. The design of a pulsating reactor for carrying out the dissolution process was proposed based on the analysis of the results of experimental and industrial tests. The described method can significantly reduce the cost of energy for mixing, in addition ensuring almost complete tightness of the reactor, and, hence, its reliability when working with potentially dangerous reagents and products.

Porosity of eight samples of natural coals was measured in which, with increasing degree of metamorphism, the content of carbon in the organic mass grows from 80 to 93%, and that of oxygen decreases from 14 to 2%. The methods of low-temperature sorption of nitrogen and mercury porosimetry were used, and the isotherm of water sorption was examined (+27°C). Each method was used to calculate the pore volume and the monolayer capacity in sorption of water and sorption of nitrogen, and the pore surface area. The Dent sorption equation was used to calculate the amounts of firmly and weakly bound water in each sample. It was shown that that the amount of strongly bound water monotonically depends on the amount of oxygen in the organic mass. For the natural coal samples under study, the volume of sorbed water is close to the total pore volume determined by the method of mercury porosimetry and is an order of magnitude larger than the pore volume measured by the method of low-temperature nitrogen sorption. Reasons for this discrepancy are discussed.

A process was developed for chromate-free passivation of zinc-plated surfaces via formation of conversion silicon-containing coatings on these surfaces. The passivation performed in a solution containing 20–35 g L⁻¹ sodium metasilicate, 0.2–0.5 g L⁻¹ phosphonic acid, 20–30 mL L⁻¹ H₂O₂, 200–500 mg L⁻¹ saccharine, and 4–10 mg L⁻¹ potassium pyrophosphate at pH 2.0–2.5 and temperature of 18–25°C in the course of 4 min. A warming-up of the solution to 40°C is allowed. The developed silicon-containing passivating coatings on zinc-plated steel details are comparable in corrosion resistance and protective capacity with iridescent chromate coatings, but, in contrast to the latter, sustain a thermal shock without deterioration of their protective characteristics and are more wear resistant.

The possibility of directional modification of the operation properties of epoxy composites by using small additions of finely dispersed electrochemically oxidized graphite was demonstrated. The optimum content of oxidized graphite as a structuring additive is 0.1 wt % relative to the epoxy compound. It ensures an 18% increase in the bending stress, a 31% increase in the bending elastic modulus, a 31% increase in the compression strength, a 53% increase in the tensile strength, a 15% increase in the tensile elastic modulus, and a 56% increase in the impact strength. Introduction of oxidized graphite influences the sample self-heating in the course of curing, Namely, the time before the onset of self-heating increases from 104 to 146 min, and the time in which the maximal self-heating temperature is reached, from 146 to 192–195 min, with the maximal self-heating temperature remaining virtually unchanged. Introduction of oxidized graphite increases the heat resistance, softening point, and thermal conductivity coefficient of the epoxy composite.

A temperature-controlled viscous acid thickener was obtained by copolymerizing acrylamide, 2-acrylamido-2-methylpropane sulfonic acid, diallyl dimethyl ammonium chloride, and N-vinyl-2-pyrrolidinone, four monomers by aqueous solution polymerization, the mass ratio of the four monomers was 6: 2: 1: 1, the reaction temperature was 45°C and the reaction time was 6 h. The total mass concentration of the monomer was 25% and the oxidation-reduction system of ammonium persulphate and sodium hydrogen sulfite (mass ratio 1: 1) was used as the initiator, the amount was 0.9% of the total mass of the monomer, and the pH of the reaction solution was 6–8. Selecting glutaric dialdehyde and zirconium(IV) acetylacetonate as cross-linking agents, and compounding the synthesized quaternary copolymer after the mass ratio of the two reagents was 1: 1 to achieve acid temperature control viscous properties, were carried out. At 90°C, the quadripolymer and the cross-linking agent were mixed at a mass ratio of 5: 3, and then cross-linked at 60, 80, and 90°C, respectively, as time increased. The apparent viscosity increased sharply, and the apparent viscosity reached a maximum after 20, 15, and 10 min, and the maximum values were 680, 690, and 750 mPa s, respectively. The reaction of marble with thickening acid (20% hydrochloric acid + 1% thickener) and temperature-controlled viscous acid (20% hydrochloric acid + 1% thickener + 0.6 cross-linking agent) was performed at 90°C. The mass loss of marble was 58 and 42% of that of 20% pure hydrochloric acid, respectively. The performance evaluation results show that the temperature-controlled viscous acid has a good compatibility, and the retarding performance is greatly improved compared with the conventional thickened acid. It has good cross-linking and gel breaking performance under high temperature conditions and is suitable for high temperature formations with temperatures above 90°C. Between its excellent compatibility, it can be selected according to the corresponding formation conditions and construction purposes, and other types of acid working fluid or oilfield additives can be used together to achieve better construction results.

The article is retracted by the Editor-in-Chief since it was submitted to two different journals with the copyright transfer agreements signed by the authors on the same day for both journals. The authors did not explain why this happened. Eventually the article was published in two journals: Russian Journal of Applied Chemistry, 2018, Volume 91, Issue 6, pp. 1002–1008 with DOI https://doi.org/10.1134/S1070427218060198 and Russian Journal of Physical Chemistry A, 2019, Volume 93, Issue 3, pp. 431–436 with DOI https://doi.org/10.1134/S0036024419030269.