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Abstract: The conversion of methane–ethane, methane–ethylene, hydrogen–ethane, and hydrogen–ethylene mixtures on an electrically heated resistive fechral catalyst is studied. In the course of conversion, the catalyst surface is covered with graphite-like carbon deposits that have an additional catalytic effect resulting in the formation of C3 and C4 hydrocarbons. The latter are apparently formed with participation of ethylene formed from ethane. Hydrogen suppresses coking on the catalyst’s surface and reduces the yield of C3 and C4 hydrocarbons. PubDate: 2021-07-01
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Abstract: A study on the synthesis of nitrous oxide via the selective oxidation of ammonia in a microreactor in the form of a metallic disk with cylindrical channels filled with a manganese–bismuth oxide catalyst has been. A 3D mathematical model is presented for this microreactor that considers the transfer of mass and axial and radial heat, the catalytic reactions, the change they produce in the volume of the reaction mixture, the transfer of heat between the disk and the channels, and the heat conductivity of the disk. Parameters are determined that ensure the maximum nitrous oxide production with allowance for the limitations of temperature in the microreactor channels. The highest efficiency of nitrous oxide production is attained at an outer reactor edge temperature of 370°C and an inlet ammonia concentration of 20 vol %. The production capacity per unit catalyst volume in the microreactor is nearly 1.5 times higher than in a tubular reactor, and the maximum temperature corresponds to the level that provides the best process selectivity toward nitrous oxide. PubDate: 2021-07-01
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Abstract: The catalytic hydrogenation of a carbon–carbon triple bond in acetylene compounds is an important industrial process in which high selectivity toward olefin compounds must be ensured. This work considers the effect of treating palladium catalysts based on hyper-cross-linked polystyrene (HPS) with sodium carbonate on the activity and selectivity in the hydrogenation of 2-methyl-3-butyn-2-ol and phenylacetylene is considered. The effect of such treatment depends on the palladium precursor and the polymer support (HPS non-functionalized or HPS containing tertiary amino groups). Selectivity in the hydrogenation of 2-methyl-3-butyn-2-ol (95% conversion of the substrate) is 98% at ambient hydrogen pressure and 90°C in toluene for 1%-Pd/HPS catalysts treated with Na2CO3 and 99.5% in the hydrogenation of phenylacetylene. PubDate: 2021-07-01
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Abstract: This review is the first part of a series of reviews devoted to the direct synthesis of organotin compounds. The conditions for and results from the reaction between tin alloys and organohalides are considered. The efficiency of catalysts and the prospects for using tin alloys in the synthesis of organotin compounds are analyzed, and some possible mechanisms of these processes are discussed. PubDate: 2021-07-01
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Abstract: The deep oxidation of hydrocarbons on platinum catalysts underlies most processes for cleaning gas emissions from industrial enterprises. Since carbon monoxide is usually present in exhaust gases, it is important to study its effect on the kinetics of hydrocarbon oxidation. This work presents results from studying the kinetics of propane oxidation on a platinum glass fiber catalyst with and without CO in the reaction mixture. It is found that CO strongly inhibits the oxidation of propane at low temperatures. The effect of CO changes from negative to positive as the temperature rises. Numerical modeling shows the multidirectionality of the effect can be explained by competition between the adsorption of oxygen, propane, and CO on the active sites of the catalyst. PubDate: 2021-07-01
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Abstract: γ-Valerolactone (GVL) is a valuable chemical compound known as a platform molecule. It is considered as an intermediate product for the synthesis of chemical compounds with high added value, components of motor fuels, and biopolymers. GVL is well established as an environmentally safe solvent, fuel additive, flavoring, and nutritional supplement. This review summarizes the latest advances in the development of catalytic ways of GVL synthesis from levulinic acid (LA), alkyl levulinates (ALs), and carbohydrates and plant polymers. Special attention is given to heterogeneous catalysts based on metals and metal oxides, which are more promising for practical application. Proposed mechanisms of the processes are considered in detail, and the prospect of using hydrogen-donor solvents in the processes of GVL production is discussed. Catalysts demonstrating the best catalytic properties are compared from the viewpoint of their productivity, an important parameter for industrial catalysis. PubDate: 2021-07-01
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Abstract: It is important today to find ways for the synthesis of hydrogen such as to avoid emissions of carbon oxides into the atmosphere and ensure the use of so-called low-carbon energy. Producing hydrogen through the thermocatalytic methane decomposition (CMD) on carbon catalysts yields not only a valuable, environmentally friendly fuel in the form of hydrogen, but also a wide range of carbon materials that can be used in a number of industries. The use of carbon catalysts is essential for the economic efficiency of methane decomposition. This paper describes the CMD fundamentals and summarizes results from studying the catalytic activity in this process for carbon materials (activated carbon, carbon black, nanotubes, nanofibers) that differ in structure and physical and chemical properties. The main problems and prospects of using this technology are identified. PubDate: 2021-07-01
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Abstract: Some specific features in the liquid-phase oxidation of alkenes to ketones or aldehydes in the presence of palladium compounds (Wacker oxidation) are discussed. It is shown that selecting the appropriate conditions of the reaction (the effective compositions of the catalyst, the oxidizing agent, and solvent) allows the selective synthesis of either ketones or aldehydes from terminal alkenes and ketones from internal alkenes. PubDate: 2021-07-01
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Abstract: The effect of the quality of Russian commercial zeolites HZSM-5 of various grades on the properties of a bifunctional cobalt catalyst in the form of a composite mixture used in the Fischer–Tropsch synthesis was studied. The activities and selectivities of the catalyst samples were compared. The fractional and hydrocarbon composition of the synthesis products was investigated. The viscosity and temperature characteristics of the diesel fraction of fuel were determined. A promising sample of zeolite HZSM-5 was chosen for practical implementation of the catalytic technology. PubDate: 2021-07-01
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Abstract: This review continues Part 1, which considered current trends in the processing of linear alpha olefins to ethylene copolymers, and anionic and nonionic surfactants. This review also briefly outlines such importnant trends in the processing of LAOs as alkylation to linear alkylbenzenes, the oligomerization of alpha olefins into poly alpha olefins, sulfonation to alpha olefin sulfonates, and other large-scale processes. PubDate: 2021-07-01
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Abstract: A study on the effect of high-temperature treatment has on the thermal stability of Sibunit, a graphite-like carbon material, under the conditions of an oxidative environment depending on the presence of the active component (Pt, Pd or Ru) has been performed. Thermal analysis results show that preliminary high-temperature treatment of Sibunit raises the temperature of the onset of carbon oxidation. It is found that keeping Ru/Sibunit samples in a nitrogen–air mixture (1 : 1) for 4 h at a temperature of 400°C results in partial destruction of Sibunit’s pyrocarbon framework and an increase in the average size of Ru particles. Using Ru as an example, it is shown that ruthenium catalysts can effectively oxidize CO at temperatures no higher than 200°C and withstand overheating up to 400°C with no appreciable loss of activity. PubDate: 2021-07-01
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Abstract: Promoters and their loading amount have crucial roles in cobalt Fischer-Tropsch catalysts. In this regard, the effects of vanadium oxide (V2O5) as a proposed promoter for Co catalyst supported on TiO2 have been investigated. Three catalysts with 0, 1, and 3 wt % of V2O5 promoter loading are prepared by the incipient wetness impregnation method, and characterized by the BET surface area analyzer, XRD, H2-TPR, and TEM techniques. The fixed-bed reactor was employed for their evaluations. It was found that the catalyst containing 1 wt % V2O5 has the best performance among the evaluated catalysts, demonstrating remarkable selectivity: 92% C5+ and 5.7% CH4, together with preserving the amount of CO conversion compared to the unpromoted catalyst. Furthermore, it is reported that the excess addition of V2O5 promoter (>1 wt %) in the introduced catalyst leads to the detrimental effect on the CO conversion and C5+ selectivity, mainly owing to diminished active sites by V2O5 loading. PubDate: 2021-04-01
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Abstract: The review presents an analysis of the scientific and technical level and tendencies in the development of modern imported and Russian catalysts for the main hydroprocesses of oil refining—hydrocracking of vacuum gas oil and hydrotreatment of various distillates (catcracked gasoline, diesel fuel, vacuum gas oil). Forecasts were made on prospects for the industrial production and mass use of Russian catalysts for hydroprocesses. PubDate: 2021-04-01
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Abstract: The literature on the existing processes for the preparation of an important organic product, methacrylic acid and its ester, methyl methacrylate is analyzed. It is shown that the main method of their industrial production are synthesis from acetone and hydrocyanic acid (acetonecyanohydrin) and catalytic syntheses from petrochemical feedstocks (ethylene, propylene and isobutylene). PubDate: 2021-04-01
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Abstract: Linear alpha olefins (LAO) are a class of chemical compounds used in the production of such high-demand products as plasticizers, synthetic lubricants, surfactants, and co-polymers with improved performance. The world consumption of LAO derivatives grows annually, as does the role of LAO processing by scientific institutions, universities, and research departments of commercial companies. Analysis of the scientific literature of the last ten years revealed no general reviews of LAO processing. This work describes recent trends in the processing of LAOs that contain four or more carbon atoms into technologically important derivatives. It lists the main products obtained via LAO processing, along with the means of their production and applications. Existing technological processes for the production of LAO derivatives and the catalysts that are used are considered briefly. Current trends in LAO processing and promising ways to improve existing technologies are described, including the development of new types of catalysts. This review does not claim to be exhaustive, since its main purpose is to give a general idea of the major trends in LAO processing, the catalysts used in these processes, and current ways of improving them. PubDate: 2021-04-01
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Abstract: New Cd–Zn/TiO2 and Cu–Zn/TiO2 catalysts based on nanodispersed titanium(IV) oxide are synthesized and characterized via X-ray diffraction analysis, low-temperature nitrogen adsorption, and temperature-programmed reduction with hydrogen. The activity of the synthesized catalysts in methanol steam reforming is studied under conditions of a microchannel reactor. It is shown that the highest activity is exhibited by Cd-containing catalysts, which are also characterized by the lowest carbon monoxide selectivity. The catalytic and physicochemical properties of the studied catalysts are compared. A correlation between the catalyst activity and the ability of Ti4+ cations in a TiO2 support to undergo partial hydrogen reduction to Ti3+ is shown. It is speculated that the reducibility of titanium cations depends on the semiconductor properties of the oxides in the catalyst. PubDate: 2021-04-01
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Abstract: A brief review is given for the results obtained by the authors at the Boreskov Institute of Catalysis when studying the processes of hydrogen peroxide oxidation for different organic compounds. Some basic catalytic systems for the synthesis of carboxylic acids as products in high demand by different branches of industry and fine organic synthesis are considered under conditions of phase-transfer catalysis. It is shown that the use of preliminarily synthesized catalytic complexes with general formula Q3{PO4[WO(O2)2]4} improves the process parameters, e.g., to increase the product yield, reduce the period of the reaction, reduce catalyst concentrations, compared to processes in which catalyst precursors are introduced into the reaction medium simultaneously with other reagents, and the active complex forms in situ. PubDate: 2021-04-01
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Abstract: A promising procedure is developed for preparing powder ZSM-5 zeolite with a high degree of crystallinity. The procedure is based on using a natural aluminosilicate as the main source of silicon and aluminum, and butanol as a template. It is shown that the porous structure of the synthesized zeolite not only has micropores, but mesopores as well. PubDate: 2021-04-01
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Abstract: This review considers the current situation in the market of phenol-formaldehyde resins, which serve as a basis for a wide range of binders, whose properties can be varied to obtain different materials for certain technological problems. The properties, types, and application fields of phenol-formaldehyde resins are characterized, and their advantages, disadvantages, and more promising potential analogues are discussed. The relevance and prospects of studies on the development of new processes and the upgrading of existing ones for the production of phenol-formaldehyde resins by both varying the process conditions and selecting the best catalyst are shown. PubDate: 2021-04-01
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Abstract: This review is the third part of a series devoted to the use of organotin compounds as catalysts in a number of important industrial processes, such as (trans)esterification and polyurethane production. The third part covers the use of organotin compounds as catalysts for the vulcanization of blocked isocyanates and silicones. PubDate: 2021-04-01
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