Showing papers in "Russian Journal of Applied Chemistry in 2018"
TL;DR: In this article, a catalyst based on zeolite was synthesized using the hydrothermal method, and alumina phosphate was embedded in its structure, which was evaluated in the process of converting methanol to dimethyl ether in a fixed-bed reactor under operating conditions of 300°C, 1 atm and 0.5 mL min'1 of feed.
Abstract: A catalyst based on zeolite was synthesized using the hydrothermal method, and alumina phosphate was embedded in its structure. The correspondent reactor tests were carried out to assess the synthesized catalyst where methanol with a purity of 99.9% was used. The results indicated that alumina phosphate is considerably effective on catalyst functionality. Given the results, the best performance was obtained when the ratio of alumina phosphate to alumina is 0.7 weighted in catalyst and fixed-bed reactor serves in a temperature of 300°C and WHSV of 0.8 h‒1. Structure and morphology of synthesized catalyst were characterized by BET, XRF, SEM, and XRD. The catalyst was evaluated in the process of converting methanol to dimethyl ether in a fixed-bed reactor under operating conditions of 300°C, 1 atm and 0.5 mL min‒1 of feed (pure methanol). The results of test indicated by increasing the amount of alumina phosphate to alumina, the conversion rate of methanol was increased to a constant value and does not change in ratios higher than 0.7. Moreover, the methanol conversion rate will reach temperature 300°C at 84%.
44 citations
TL;DR: In this article, a review of the past decade's work on 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 is presented.
Abstract: 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.
26 citations
TL;DR: In this paper, Urea-formaldehyde (UF) microcapsules loaded with linseed oil (LO) and benzotriazole (BTA) as core materials have been synthesized by in situ emulsion polymerization.
Abstract: Urea-formaldehyde (UF) microcapsules loaded with linseed oil (LO) and benzotriazole (BTA) as core materials have been synthesized by in situ emulsion polymerization. The capsules were characterized by FTIR spectroscopy and particle size analysis. Surface morphology of the microcapsules was analyzed using scanning electron microscopy (SEM). The microcapsules were incorporated into epoxy resin and coated on a mild steel substrate to form a corrosion resistant organic coating. The self-healing property of coatings loaded with different weight % of microcapsules containing LO + BTA was tested by immersion of the UF coated mild steel specimens in 3.5 wt % NaCl solution. It was analyzed through visual inspection, weight loss measurements, and SEM of the scribed region of coating. It was observed that the addition of microcapsules enhances the corrosion resistance of the scratched samples.
23 citations
TL;DR: Fylolflex oligo(resorsinol phenyl phosphate) with terminal phenyl groups is an effective plasticizer for an epoxy polymer, allowing the development of compounds with enhanced levels of physicomechanical properties, heat resistance, softening point, an flame resistance as mentioned in this paper.
Abstract: Fylolflex oligo(resorsinol phenyl phosphate) with terminal phenyl groups is an effective plasticizer for an epoxy polymer, allowing the development of compounds with enhanced levels of physicomechanical properties, heat resistance, softening point, an flame resistance. Introduction of chromite, a cheap and active filler, into the epoxy polymer in amounts of 0.1 and 100 wt parts enhances the physicochemical and mechanical properties of the composite. Namely, the Vicat softening point increases from 132 to 140–250°С, the degradation onset temperature increases, and the yield of carbonized structures increases from 54 to 68–86 wt %, which leads to a decrease in the release of volatile pyrolysis products into the gas phase and in the combustibility of the epoxy composite.
20 citations
TL;DR: In this paper, the microhole machining is performed on the copper inorganic work piece and the electrolyte has been heated using ultraviolet (UV) rays during the machining.
Abstract: The need for micro components/devices in the field of aerospace, automobile and medical is increasing day by day. There are various methods are available for manufacturing of such components/devices. Among the various non-traditional machining techniques, electrochemical micromachining is found to be more suitable due to the reason for its higher material removal rate, good surface quality and accuracy. In this research the microhole machining is performed on the copper inorganic work piece. During the machining, electrolyte has been heated using ultraviolet (UV) rays. L18 orthogonal array (OA) is planned using electrolyte concentration (Ce), machining voltage (Vm), duty cycle (Cd) and electrolyte temperature (Te). The process parameters are optimized using technique for order of preference by similarity to ideal solution (TOPSIS) and grey relational analysis (GRA). Two optimal parametric combinations are obtained, such as 30 g L–1, 7 V, 65% and 34°C using TOPSIS and 30 g L–1, 9 V, 55% and 36°C using GRA. Based on ANOVA the electrolyte concentration shows nearly 65% contributions among the other process parameters. Additionally Scanning electron microscope (SEM) images have been used for the better understanding of roundness of micro-hole.
19 citations
TL;DR: In this article, sulfuric and nitric acids were used to functionalize asphaltenes isolated from heavy crude oil by treatment with heptane or hexamethyldisiloxane.
Abstract: Sulfuric and nitric acids were used to functionalize asphaltenes isolated from heavy crude oil by treatment with heptane or hexamethyldisiloxane. The elemental composition of the asphaltenes was analyzed and their functional groups before and after the modification were identified. It was shown that the content of heteroatoms in the modified asphaltenes increases. Carbonyl, carboxyl, sulfonic, and nitro groups appear in the asphaltenes with the content dependent on the type of a modifier used and on the prehistory of how they were obtained.
17 citations
TL;DR: In this paper, the results obtained in synthesis and certification of new materials based on Ba-doped Ln2NiO4+δ as possible electrode candidates for electrochemical devices with solid-oxide proton-conducting electrolytes are presented.
Abstract: Results obtained in synthesis and certification of new materials based on Ba-doped Ln2NiO4+δ as possible electrode candidates for electrochemical devices with solid-oxide proton-conducting electrolytes are presented. Single-phase materials of composition Ln1.95Ba0.05NiO4+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 Pr1.95Ba0.05NiO4+δ with a small fraction of the electrolyte component.
17 citations
TL;DR: In this article, the authors studied the effect of the textural characteristics of the support and acidity of the materials on the catalyst activity in isomerization of o- and m-xylenes and of ethylbenzene with the aim of obtaining p-xylene.
Abstract: Pt-containing catalysts based on halloysite aluminosilicate nanotubes and ZSM-5 zeolite were synthesized. The structure of the materials was confirmed by low-temperature nitrogen adsorption/desorption and by transmission electron microscopy. The activity and selectivity of the synthesized catalysts based on micromesoporous supports in isomerization of the xylene reforming fraction was studied on a flow-through laboratory installation with a fixed catalyst bed in the temperature interval 360–440°С at elevated hydrogen pressure. The influence exerted by the textural characteristics of the support and acidity of the materials on the catalyst activity in isomerization of o- and m-xylenes and of ethylbenzene with the aim of obtaining p-xylene was studied.
17 citations
TL;DR: In this article, the influence of the base oil viscosity and/or thickener structure on the physicochemical properties of greases based on poly-α-olefin oils of various viscosities, thickened with diureas of various structures, was demonstrated.
Abstract: Greases based on poly-α-olefin oils of various viscosities, thickened with diureas of various structures, were studied systematically. The influence of the base oil viscosity and/or thickener structure on the physicochemical properties of lubricants was demonstrated. Diurea thickeners differing in the length of the hydrocarbon substituent influence the properties of lubricants prepared with base oils of similar chemical nature but different viscosity in different fashion. The revealed trends were confirmed by rheological studies in a wide range of shear rates. Tribological measurements at loads in the interval 20–80 kgf demonstrated significant dependence of the antiwear properties of ureate lubricants based on low-viscosity poly-α-olefin oils on the thickener structure. This dependence becomes less pronounced in going to higher-molecular-mass oils.
15 citations
TL;DR: The main applications and ways of utilization of industrial lignins, which are a large-tonnage waste from pulp and hydrolysis plants, are considered in this paper.
Abstract: The main applications and ways of utilization of industrial lignins, which are a large-tonnage waste from pulp and hydrolysis plants, are considered. The first group of methods includes nonthermal methods of lignin processing with preservation of the natural polymeric structure of lignin. The second group of methods includes thermal methods for lignin processing with the formation of low- and high-molecular-mass compounds and combustible gas. The largest-tonnage application fields of lignins are building, mining, metallurgical, oil-extracting, and agro industries, and also water treatment.
15 citations
TL;DR: In this article, a method of scientific experiment design based on the Taguchi matrix technique was used to rank basic technological parameters (bias voltage applied to the substrate holder, output power of the high-frequency generator, oxygen flow rate, and position of substrate holder relative to the lower edge of the discharge chamber) as regards their influence on the etching rate.
Abstract: Process for deep plasma-chemical etching of single-crystal quartz plates in a SF6/O2 gas mixture was developed. The method of scientific experiment design based on the Taguchi matrix technique was used to rank basic technological parameters (bias voltage applied to the substrate holder, output power of the high-frequency generator, oxygen flow rate, and position of the substrate holder relative to the lower edge of the discharge chamber) as regards their influence on the etching rate. The ranking results were used to optimize the plasma-chemical etching process and perform a control experiment on through etching of windows with large linear dimensions (3 × 10 mm) in a single-crystal quartz plate (z-cut) with thickness of 369 μm.
TL;DR: In this article, specific features of composite materials based on polyethylene, multi-walled carbon nanotubes, and cobalt nanoparticles (MWCNT-PE) by in situ polymerization were revealed.
Abstract: Specific features of formation of composite materials based on polyethylene, multi-walled carbon nanotubes, and cobalt nanoparticles (MWCNT–PE and Co/MWCNT–PE) by in situ polymerization were revealed. The in situ polymerization technique is based on ethylene polymerization on a highly dispersed Ti-containing catalyst supported on the surface of MWCNT and Со/MWCNT. This method ensures uniform distribution of MWCNT and Co/MWCNT in the polyethylene matrix. The effect of MWCNT and Со/MWCNT on the final properties of the composite materials was determined. Introduction of MWCNT into the polyethylene matrix increases the specific electrical conductivity of the material. Such composite materials can be used for preparing concentrates with preset composition for the subsequent preparation of antistatic coatings. Introduction of the Со/MWCNT filler into the polyethylene matrix makes the material paramagnetic owing to Co nanoparticles and allows its use for preparing coatings that efficiently protect from electromagnetic radiation.
TL;DR: In this paper, a novel nanostructured hydrotalcite-supported alkali-doped ruthenium-based catalyst is introduced for the direct gas-phase conversion of ethylene to propylene at 70°C and 1 atm.
Abstract: A novel nanostructured hydrotalcite-supported alkali-doped ruthenium-based catalyst is introduced for the direct gas-phase conversion of ethylene to propylene at 70°C and 1 atm. The maximum conversion of ca. 87% was obtained at the initial time on stream with a 65% selectivity to propylene and a 6% selectivity to butenes via consecutive reactions. Both conversion and selectivity to olefinic products decreased after 24 min of operation, however.
TL;DR: In this article, the melting point of polyhydroxybutyrate and polylactide in the blends changes insignificantly, by 1-2°C, and physicomechanical properties of the samples are determined by the major phase.
Abstract: Blends of polylactide with low-density polyethylene and of poly-3-hydroxybutyrate with synthetic ethylene–propylene rubber with the component weight ratios of 30 : 70, 50 : 50, and 70 : 30 were prepared and studied in comparison with the pure components. The thermal characteristics of these blends were determined by differential scanning calorimetry. The melting point of polyhydroxybutyrate and polylactide in the blends changes insignificantly, by 1–2°C. The dependence of the morphology on the composition for both polymer systems was examined by scanning electron microscopy. The physicomechanical properties of the samples are determined by the major phase. The blends undergo biodegradation in soil at 20 ± 3°С. The process occurs faster for blends of polyhydroxybutyrate with ethylene–propylene rubber of all the compositions studied.
TL;DR: In this paper, the physicochemical characteristics and hydrocarbon composition of highly aromatic wastes (light gas oil from catalytic cracking, pyrolysis tar, coal tar and coal gasification tar) as a feedstock for producing high-density jet fuels are considered.
Abstract: Physicochemical characteristics and hydrocarbon composition of highly aromatic wastes (light gas oil from catalytic cracking, pyrolysis tar, coal tar, coal gasification tar) as a feedstock for producing high-density jet fuels are considered. The hydrogenation reactions of polycyclic aromatic hydrocarbons, including mixtures of hydrocarbons with different numbers of rings, are described. Catalysts for hydrogenation of highly aromatic waste to obtain fuel fractions are considered. Particular attention is paid to catalyst deactivation in the course of processing of this feedstock. A separate section deals with the choice and implementation of procedures for processing highly aromatic feedstock to obtain jet and diesel fuels.
TL;DR: The state of the art in production and consumption of carbon sorbents and the main directions of research in this field are considered in this paper, where the advantages and drawbacks of lignin as a raw material are discussed.
Abstract: The state of the art in production and consumption of carbon sorbents and the main directions of research in this field are considered. Approaches to preparing sorbents derived from lignin are summarized. The advantages and drawbacks of lignin as a raw material and prospects for the progress in this field are discussed.
TL;DR: The possibility of using crude glycerol as a feedstock for preparing solketal is demonstrated and the specific features of thesolketal synthesis from crude glycersol and of separation of the reaction products are described.
Abstract: Information on the volume of production of biodiesel and crude glycerol from it is analyzed. The possibility of using crude glycerol as a feedstock for preparing solketal is demonstrated. The specific features of the solketal synthesis from crude glycerol and of separation of the reaction products are described. A catalytic process is suggested for selective decomposition of solketal to glycerol to obtain purified glycerol of any required concentration up to 99.8 wt %. A flowsheet is suggested for processing of crude glycerol to obtain solketal and subsequently converting it to obtain pure glycerol.
TL;DR: In this article, the efficiency and feasibility of two main synthetic routes to 2-vinylnorbornane, heterocodimerization of ethylene with norbornene, and selective hydrogenation of 5vinyl-norborn-2-ene, were compared on the basis of the available papers and patent data.
Abstract: The existing methods for synthesizing 2-vinylnorbornane were considered comprehensively. The efficiency and feasibility of two main synthetic routes to 2-vinylnorbornane, heterocodimerization of ethylene with norbornene and selective hydrogenation of 5-vinylnorborn-2-ene, were compared on the basis of the available papers and patent data.
TL;DR: The main procedures for producing terephthalic acid from p-xylene (primarily the Amoco process with the participation of Co, Mn, and Br salts), the oxidation mechanisms, alternative processes, and perspectives are discussed in this paper.
Abstract: The review discusses the main procedures for producing terephthalic acid from p-xylene (primarily the Amoco process with the participation of Co, Mn, and Br salts), the oxidation mechanisms, alternative processes, and perspectives
TL;DR: In this article, a 15 μg of ZnO nanoparticles liquefied in 1 mL of dimethyl sulfoxide revealed outstanding 95.04 ± 1.37 % inhibition activities against growth of C. coli.
Abstract: Zinc oxide (ZnO) nanoparticles have been synthesized by co-precipitation method. The structural properties like average crystallite size, lattice parameters, volume of unit cell, and X-ray density were studied by XRD. The crystallite size was measured by using Scherrer formula. It was observed that the average crystallite size increased with the increase of annealing temperature. Morphology of the synthesized oxides was investigated by SEM. The harmful constituents like organic compounds have been removed from waste water that is toxicant. Metal oxide semiconductors had shown good photocatalytic activity to degrade harmful organics into less harmful molecules under light-illumination. In this regard the dye (Rhodamine B) was degraded with increasing exposure time of UV radiations. Almost 60% dye degradation was observed in 150 min. The ZnO was also employed as an active anti-microbial nanomaterial on the growth of C. coli. A 15 μg of ZnO nanoparticles liquefied in 1 mL of dimethyl sulfoxide revealed outstanding 95.04 ± 1.37 % inhibition activities against growth of C. coli.
TL;DR: In this article, a review of greases in which organic ureas of various compositions and structures are used as thickeners is presented. And the physicochemical, tribological, and operation properties of plastic polyurea lubricants are discussed.
Abstract: The review deals with greases in which organic ureas of various compositions and structures are used as thickeners. The nature of compounds participating in the synthesis of organic ureas and the main types of polyurea thickeners are considered. The physicochemical, tribological, and operation properties of plastic polyurea lubricants are discussed.
TL;DR: In this article, the influence of forming conditions on the structure and properties of Aquivion® perfluorinated proton-conducting membranes prepared by casting from a dimethylformamide solution was studied.
Abstract: The influence of the forming conditions on the structure and properties of Aquivion® perfluorinated proton-conducting membranes prepared by casting from a dimethylformamide solution was studied. At properly chosen and controlled conditions of solvent evaporation and subsequent heat treatment, membranes with more ordered morphology and structure, high level of mechanical properties, and high proton conductivity can be obtained. These results are attributed to the structural self-organization of the polymer base of the membranes in the course of nanofilm formation. The properties of Aquivion® type membranes prepared by casting and pressing were compared. The possibility of improving the strength properties of the membranes to the level close to that of the membranes prepared by extrusion was demonstrated.
TL;DR: In this article, an experimental study on the pyrolysis of scrap tires under different operating conditions such as feedstock size and pyrolyssis temperature was conducted, highlighting the properties of the whole liquid products generated during each thermal degradation process.
Abstract: This investigation involves an experimental study on the pyrolysis of scrap tires under different operating conditions such as feedstock size and pyrolysis temperature by highlighting the properties of the whole liquid products generated during each thermal degradation process. The complete conversion temperature for the pyrolysis of used tires was close to 500‒550°C. The characteristics of liquid fraction were determined by elemental analysis, chromatographic and spectroscopic techniques and distillation data. All the obtained atomic ratios are around 1,4 which is significant that such pyrolytic liquids are a mixture of aliphatic and aromatic compounds derived from polymeric materials. Analysis of the pyrolytic oil (pyro-oil) by chromatographic analysis showed that it was a complex mixture of organic compounds C5‒C26, aromatics and a large proportion of light hydrocarbons that can be used as liquid fuels. Furthermore, the comparison distillation data indicates that more than 40% of such pyrolytic oil fraction with the boiling point range between 180‒360°C is specified for diesel. It is noted that the viscosity decreases obviously from 4.87 to 1.79 with the increase in temperature.
TL;DR: The main problems of the development of heavy oil fields and the ways of their solution are considered in this article, where modern nontraditional methods for extracting heavy crude oils, ensuring their in situ upgrading, such as aquathermolysis, combination of catalytic upgrading and in situ combustion, and in- situ electric heating, are analyzed.
Abstract: The main problems of the development of heavy oil fields and the ways of their solution are considered. The modern nontraditional methods for extracting heavy crude oils, ensuring their in situ upgrading, such as aquathermolysis, combination of catalytic upgrading and in situ combustion, and in situ electric heating, are analyzed. Research fields that could bring the technologies for heavy crude oil extraction closer to the ready-touse level are outlined. The main processes allowing heavy crude oil to be involved in processing at the existing oil refineries are considered, and the Russian experience in this field is demonstrated.
TL;DR: In this article, a polytetraurethane diepoxides was prepared from oligo(tetramethylene oxide)diols of various molecular masses, various diisocyanates, and glycidol.
Abstract: New polytetraurethane diepoxides were prepared from oligo(tetramethylene oxide)diols of various molecular masses, various diisocyanates, and glycidol. High-strength frost-resistant cold-curable elastic compounds were prepared on their basis. The use of aminoethylpiperazine as a curing agent allows the cured materials to be prepared in 24 h at room temperature. The elastomers based on isophorone diisocyanate exhibit higher mechanical and thermal characteristics than those based on 2,4-toluene diisocyanate, which is due to higher degree of microphase segregation of soft and hard blocks of elastomers based in isophorone diisocyanate.
TL;DR: Magnesium and calcium coordination compounds were studied as L-lactide ring-opening polymerization catalysts in this paper, and the solvent effect on polymerization rate and molecular-mass characteristics of the polymers obtained was demonstrated.
Abstract: Magnesium and calcium coordination compounds (dpp-bian)Ca(thf)4 (1), (dpp-bian)2Mg (2), and (dpp-bian)2Ca (3), containing a chelating redox-active acenaphthenediimine ligand, dpp-bian {1,2-bis-[(2,6-diisopropyl)phenylimino]acenaphthene}, were studied as L-lactide ring-opening polymerization catalysts. The interaction of complex 1 with L-lactide in solution was studied by ESR spectroscopy. The solvent effect on the polymerization rate and molecular-mass characteristics of the polymers obtained was demonstrated.
TL;DR: In this article, the deposition of chromium coatings from an electrolyte based on a deep eutectic solvent (new type of ionic fluids) was studied and the manner in which the electrolysis conditions affect the current efficiency for chromium deposition was determined.
Abstract: Deposition of chromium coatings from an electrolyte based on a deep eutectic solvent (new type of ionic fluids) was studied. The electrolyte used to deposit the coatings contained choline chloride, chromium(III) chloride, and addition of water. It was found that introduction of a certain amount of water makes it possible to raise the electrical conductivity and reduce the viscosity of the electrolyte to values acceptable for its practical application. The manner in which the electrolysis conditions affect the current efficiency for chromium deposition was determined. It was shown that uniform hard chromium coatings with good adhesion to the substrate can be deposited.
TL;DR: In this paper, a two-step electrodialysis treatment scheme was proposed to remove heat stable salts from aqueous solutions of alkanolamine absorbents, with monoethanolamine as example.
Abstract: Electrodialysis technology was adapted to removal of heat stable salts from aqueous solutions of alkanolamine absorbents, with monoethanolamine as example. Removal of anions of heat stable salts by electrodialysis from a 30 wt % aqueous solution of monoethanolamine with the degree of carbonation of 0.2 mol of CO2 per mole of monoethanolamine was studied. The two-step removal of heat stable salts by electrodialysis allows the monoethanolamine loss to be reduced and the concentration of residual CO2 in the absorbent solution to be decreased. The suggested two-step electrodialysis treatment scheme allows the concentration of heat stable salts to be maintained on the required level from the viewpoint of their corrosion activity, the total volume of the concentrate to be decreased by 50%, and the monoethanolamine loss to be decreased by 30%. The treatment unit with the circulation volume of the monoethanol absorbent of 100 m3 h–1 was calculated for confirming the efficiency of the two-step electrodialysis treatment scheme. As compared to the one-step electrodialysis treatment scheme, the two-step scheme ensures recovery of 50% of monoethanolamine at the same efficiency of the removal of heat stable salts.
TL;DR: In this paper, the degree of immobilization of montmorillonite on flax fiber was determined experimentally, and the effect of nonadditive increase in the sorption capacity of the biocomponent material was evaluated.
Abstract: The degree of immobilization of montmorillonite on flax fiber was determined experimentally, and the effect of the nonadditive increase in the sorption capacity of the biocomponent material was evaluated. Studies of pectin–montmorillonite model systems using methods of laser diffraction, X-ray diffraction, and gas adsorption revealed the formation of associate pairs with an equivalent increase in the pectin particle size, a threefold increase in the interlayer distance in the mineral structure, and a superadditive increase in the pore structure parameters. These effects prove formation of hybrid composites with limited intercalation of pectin polymer chains.
TL;DR: In this article, chemical modification of the surface of noble metal nanoparticles and their use in analytical and bio-analytical chemistry, pharmacology, etc., are analyzed, and the results show the potential for using the modified nanoparticles in various branches of science and engineering, primary in chemical and biochemical analysis and also in pharmacology.
Abstract: Papers dealing with chemical modification of the surface of noble metal nanoparticles and their use in analytical and bioanalytical chemistry, pharmacology, etc., are analyzed. Grafting of a layer of preset chemical composition on the nanoparticle surface allows preparation of functional materials combining the properties of the metal core (surface plasmon resonance, enhancement of fluorescence and nonelastic scattering) and shell (selective interaction with components of the surrounding medium). Combination of these properties opens wide prospects for using the modified nanoparticles in various branches of science and engineering, primary in chemical and biochemical analysis, and also in pharmacology.