Vol 92, No 5 (2019)

The review deals with extraction refining of straight-run diesel fractions, atmospheric gasoil, gasoils from secondary oil refining processes (decelerated coking, visbreaking, catalytic cracking), and light and heavy vacuum gasoils to remove heteroatomic sulfur- and nitrogen-containing compounds, polycyclic arenes, and resins using selective organic solvents and extraction systems with a nonpolar solvent. Possible methods for extraction regeneration and extract application fields are considered.

The method of deposition from the gas phase is applied to the synthesis of thin films of molybdenum disulfide. It was established that varying the rate of temperature rise in the course of the synthesis affects the character of growth and the structure of the layers formed. With a decrease in the rate of temperature rise, a transition from standard two-dimensional to screw growth of MoS₂ films is observed. MoS₂ films produced as a result of screw growth have a high density of edge states, which makes them promising for use in catalysis.

The features of burning of solid propellant with a high metal content (over 40%) under conditions of a separately located gas generator of an air-jet engine were investigated. It was shown that solid propellant with a high metal content burns in the mode of dominant heat release in the condensed phase. It was found that metal propellant under conditions of the condensed phase is not a simple heat sink, but plays an active role in burning. The oxidation of the metal under the conditions of the condensed phase maintains the thermal balance of the condensed phase during burning of solid propellant.

Nickel-based composite electrochemical coatings modified with graphite bisulfate were obtained. The functional properties (sliding friction coefficient, protective capacity) of these coatings as compared with nickel coatings without a dispersed phase were examined. It was found that, when graphite bisulfate particles are incorporated in nickel deposits, the coefficient of sliding friction becomes 2.30–2.40 smaller and the range of passive-state potentials increases by a factor of 1.32–1.40.

The physicochemical and sorption properties of hydroxyapatite synthesized in the presence of oxyethylidenediphosphonic acid, as crystallization inhibitor, were studied. The effect of acid concentration and calcium phosphate reagents was established on the sorption properties of hydroxyapatite with respect to ions Co²⁺, Pb²⁺, and Sr²⁺. It was shown that the sorption capacity of amorphous hydroxyapatite obtained in the presence of 1.0 mol % oxyethylidenediphosphonic acid, for Co²⁺ and Sr²⁺ ions, increases by 2–2.5 times, and for Pb2+ ions, by 4–5 times compared to crystalline hydroxyapatite obtained without acid additives. It was revealed that the observed differences in the sorption capacity of amorphous and crystalline hydroxyapatite with respect to the studied metal ions are due to different mechanisms of their adsorption.

Effects are compared of various surfactants on the properties of an impregnating solution of nickel and aluminum nitrates in the condensate, used in manufacture of supported catalysts for conversion of methane. It was shown that use of synthanols (oxyethylated alcohols, which are nonionogenic surfactants) makes it possible to significantly (by three orders of magnitude) reduce the necessary content of surfactants in solution, which is confirmed by many years of industrial experience. Results are presented of quantum-chemical calculations of the interaction of synthanol molecules with nickel ions. The use of synthanol can substantially reduce the probability of carbonization of the catalyst surface and the possible carryover of a part of metal ions with the impregnating solution and also diminish the toxicity and the explosion hazard in the production area.

Method of coprecipitation with a subsequent thermal treatment was used to synthesize highly dispersed Mn₂O₃-Bi₂O₃-ZrO₂-CeO₂ solid solutions. The elemental and phase compositions, texture characteristics, dispersity, and morphology were examined. The thus synthesized samples exhibit a high activity in the reaction of CO oxidation. It was shown that the nature of doping ions (Bi³⁺, Nd³⁺, Sn³⁺, Gd³⁺) affects the catalytic activity of the materials. The highest catalytic activity was observed for the Gd_0.05Bi_0.05Zr_0.18Ce_0.72O₂ sample.

The radical copolymerization of norbornene with norbornenyl acrylate or bornyl acrylate has been studied. New copolymers containing norbornane moieties in the side chain were produced. The influence of the reaction conditions on the composition, molecular weight characteristics, and glass transition temperature of the copolymers was studied. It was established that copolymers of norbornene with norbornenyl acrylate or bornyl acrylate have high transparency (95–97%) in the visible region (400–800 nm) and glass transition temperature. They effectively stabilize semiconductor nanoparticles, which allows these new copolymers to be considered as promising materials for optoelectronics.

Polyisoprenes synthesized on titanium–magnesium catalysts were studied by ¹H and ¹³C NMR spectroscopy (Larmor’s frequency for protons 700 MHz). The problems concerning the accuracy of determining the microstructure of polyisoprenes with high content of trans units are discussed. As demonstrated for a series of samples with varied configurational and isomeric composition, the cis and trans units are distributed in the macromolecules in the block (continuous) fashion, whereas the 3,4-units are distributed randomly.

The effect of direct gas fluorination on the surface properties of a nonwoven polypropylene material was studied. Direct gas fluorination with mixtures of different compositions allows directional variation of the surface properties of the nonwoven polypropylene material. The surface becomes more hydrophobic when using a mixture of fluorine and nitrogen but less hydrophobic when using a mixture of fluorine, oxygen, and nitrogen. The modification leads to changes in the chemical composition of the surface and in the roughness of the material. The nonwoven polypropylene materials thus obtained exhibit increased sorption capacity for spent oil or water, respectively. Variation of the properties of the nonwoven polypropylene material allows expansion of its applications.