卷 91, 编号 4 (2018)

Papers published in the past decade on oxidative desulfurization of hydrocarbon raw materials using hydrogen peroxide, oxygen, and ozone as oxidants, and also using ultrasonic treatment and adsorption and extraction methods for separating the oxidized sulfur-containing compounds are summarized and systematized.

Methods for obtaining aluminum materials modified with silicon carbide particles were studied. The oxidation resistance of silicon carbide in an aluminum matrix was examined under microarc oxidation in an electrolyte based on boric acid. A protective composite-based silicon-containing oxide coating was obtained with low porosity and microhardness of up to 9.0 GPa.

Formation of the metal is observed under irradiation of methanol-containing aqueous solutions of cadmium salts with accelerated electrons. The process of precipitation of the metal and its properties was examined. The radiation-chemical yield is (1.7 ± 0.2) × 10^–2 g kGy. The efficiency of the radiation-induced reduction of a number of other metals in aqueous media: copper, lead, and thallium, was substantiated. The method may be promising for obtaining deposits of pure and amorphous metals from aqueous solutions of their salts and for purification of aqueous effluents containing these toxic metals.

Microcrystalline metallic bismuth powders of varied morphology were obtained by reduction of bismuth precursors, basic bismuth formate and bismuth(III) formate in benzyl alcohol, hydrazine hydrate, and sodium borohydride. The methods of X-ray diffraction analysis, scanning electron microscopy, thermogravimetry, and differential scanning calorimetry were used to examine the phase composition and the morphology of the resulting metallic bismuth powders. A dispersion analysis of bismuth samples was made by the method of small-angle scattering of light for a proximate monitoring of the particle size in powders of different fractions. The specific surface area of the metallic bismuth sample was determined by the thermal desorption of argon.

Nine heterocyclic and aromatic azo derivatives of phenol and 1-naphthol were studied as flotation collectors of sulfide ores of non-ferrous metals. The constants of acid dissociation of compounds in aqueous solutions and their solubility in alkaline media are determined. It has been established that the adsorption of reagents on the surface of sulfide copper-nickel ore has a physical character. The adsorption constants are calculated. It is shown that the reagents under study exhibit collective properties with respect to the sulfide minerals of copper, cobalt and nickel. The use of mixtures of azo compounds with potassium butyl xanthate leads to an increase in both the recovery degree and the quality of the concentrate for nickel and copper in comparison with a single butyl xanthate.

Results obtained in synthesis and certification of new materials based on Ba-doped Ln₂NiO_4+δ as possible electrode candidates for electrochemical devices with solid-oxide proton-conducting electrolytes are presented. Single-phase materials of composition Ln_1.95Ba_0.05NiO_4+δ (Ln = La, Nd, and Pr) were obtained by using the citrate-nitrate synthesis method, and their thermomechanical, electrical, and electrochemical functionality was examined with the use of the dilatometric method, four-probe dc measurements, and electrochemical impedance spectroscopy, respectively. An integrated analysis of the data obtained shows that the highest electrical transport properties, which compare well with modern results, were reached for the Pr-containing nickelite. At the same time, this nickelite has an increased thermal expansion coefficient, which exceeds by ~20% that for the electrolyte material. These characteristics can be optimized by creating composite materials based on Pr_1.95Ba_0.05NiO_4+δ with a small fraction of the electrolyte component.

Bubbling in the liquid phase simulating the reaction medium consisting of molten paraffin and iron-containing nanosized catalyst was studied. An aerator (disperser) for a model bubbling installation with the design and process parameters maximally similar to those of an intended slurry reactor with nanosized iron-containing catalytic suspension for performing Fischer–Tropsch synthesis was chosen.

A new procedure for gasification of powdered solid fuel in a flow of a gaseous oxidant in the course of filtration of the mixture through an inert packing was suggested and tested. This procedure allows the productive capacity of a single reactor to be increased owing to acceleration of the reactions, i.e., to an increase in the reaction surface area with a decrease in the fuel particle size. As shown in cold (without ignition) experiments, the powdered fuel was partially accumulated in the inert porous packing, which led to the pressure buildup in the reactor. In gasification experiments with ignition, the powdered fuel was not accumulated in the reactor if the temperature in the fuel feeding zone was no less than 500°С. In this case, the linear velocity of the gas increased owing to thermal expansion, and this velocity was sufficient for the coal particles fed to the reactor to be entrained by the flow.

The morphology, structure, phase composition, and properties of composite materials based on polytetrafluoroethylene and oxyfluoride glass–ceramic of the composition 18LiF–31SiO₂–19B₂O₃–24BaO–8TiO₂ were studied.

Highly hydrophobic epoxy coatings with the surface energy as low as 14.5 mJ m^–2 and contact angles with water of 120°–150° were prepared from powdered compounds modified with less than 2 wt % finely dispersed polytetrafluoroethylene particles by dry mixing. As shown by scanning electron microscopy, EDX microanalysis, and atomic-force microscopy, the film formation at 180°С and formation of a polymer network matrix are accompanied by predominant migration of polytetrafluoroethylene particles to the air/coating interface, leading to gradient distribution of fluorine across the film and significant enrichment of the coating surface with fluorine. By varying the polytetrafluoroethylene content, it is possible to obtain hydrophobic coatings with satisfactory physicomechanical properties, smooth or rough surface, including micrometric and nanometric roughness, and different surface energy.

Possibility of using a low-temperature magnesium-potassium phosphate matrix to solve the problem of immobilizing the radioactive wastes containing radioactive carbon (¹⁴C) in the form of calcium carbonate was examined. The physicochemical characteristics of the compounds obtained were determined. Large values of the ultimate compression strength (22 ± 5 MPa), which satisfy the technical requirements for cemented radioactive wastes (no less than 4.9 MPa), were obtained. The minimum carryover of carbon dioxide into the atmosphere in the course of synthesis and in keeping of samples for 14 days was noted: not more than 3 wt % relative to the starting CaCO₃. The leaching rate of carbonate ions from magnesium-potassium compounds by 28th day of contact with air does not exceed 10‒9 g cm^‒2 day^‒1, with this value for the rest of the compound components not exceeding 10^‒4 g cm^‒2 day^‒1. Thus, it was found that the magnesium‒potassium phosphate matrix is an alternative to the cementation for solidification of radioactive wastes containing ¹⁴C.

Thermobaric conditions of gas hydrate formation in the presence of the carboxymethylcellulose sodium salt were studied under conditions of a quasi-equilibrium thermodynamic experiment. It is established that this polysaccharide slows down the rate and changes the conditions of gas hydrate formation, showing the properties of the thermodynamic and kinetic inhibitor with an efficiency exceeding 300 times the methanol when used in the same dosages.

It is suggested to use a binary solvent, 1-butyl-3-methylimidazolium acetate + dimethyl sulfoxide, for full dissolution of wood, followed by its separation into the polysaccharide and lignin components. The optimal conditions of the wood treatment process were determined (temperature 120°C, processing duration 6 h). A scheme is suggested for double-stage fractionation of the lignin‒cellulose biomass. The scheme is based on the successive precipitation of the dissolved components with acetone and water. The isolated polysaccharide and lignin fractions constituting, combined, 70% of the initial mass of wood were characterized by IR and NMR spectroscopy, exclusion chromatography, electron microscopy, and functional analysis. It was found that the polysaccharide fraction has the form of amorphous cellulose (2% degree of crystallinity) containing about 15% lignin. The isolated lignin contains no significant admixtures of polysaccharides, has a mass-average molecular mass of about 5 kDa, and is close to organosolvent lignins. It was found that the lignin fraction contains up to 35% residual ionic fluid. A suggestion is made about the possibility of chemical binding between lignin and butyl-3-methylimidazolium cations.

A novel phosphorous containing flame retardant epoxy resin is synthesized by modifying the epoxy resin initially with phosphoric acid and further with aluminum hydroxide (ATH) to enhance the fire retardancy of the modified epoxy resin. The several phosphorous modified epoxy resin to ATH mass ratios were used to study the effect of ATH addition on epoxy. Thermal and mechanical properties. The structure of the modified flame retardant epoxy resin was characterized using Fourier-transform infrared spectroscopy (FTIR) while thermal degradation behavior and flame retardant properties were examined using thermo-gravimetric analysis (TGA) and UL-94 testing. Furthermore, ultimate tensile strength and young modulus were analyzed to study the effect of ATH addition on mechanical properties. The findings indicated that fire retardancy of ATH reinforced modified ep oxy resin is higher than virgin and phosphorous modified epoxy resin and depicted eminent flame retardant properties with suitable mechanical properties.

Methods for the synthesis of 4-chlorophenylsulfonylacetic acid and its tris(2-hydroxyethyl)ammonium salt (“sulfacetamine”) were studied. The results of in vitro and in vivo experiments showed that sulfacetamine possesses high antithrombotic, antioxidant, hypocholesterolemic, immunostimulating, and protective-adaptive activities.