Dimethyl ether (DME) is a promising multisource and multipurpose clean fuel and value-added chemical synthesized from syngas. This process can be either performed in a single stage (direct process) using a dual catalysis system or a two stage (indirect process) where syngas is first converted into methanol and then dehydrated to produce DME. While the dehydration reaction has been studied extensively over multiple decades, to date no review has been conducted on the catalysts involved in the methanol dehydration reaction. This work demonstrates the state of the art in catalyst preparation and analysis for this application. The dominant catalysts are studied extensively in this work, including γ-Al₂O₃ and various zeolites, such as ZSM-5, Y, beta and mordenite as well as their relevant modifications. Additionally, silicaalumina, mesoporous silicates, aluminum phosphate, silicoaluminophosphates, heteropoly acids (HPAs), metal oxides, ion exchange resins and quasicrystals are discussed in this work, owing to the wide variety of catalysts available and studied for the purposes of methanol dehydration to DME.

The influence of modifying HZSM-5 zeolite as a component of a bizeolite catalyst in transformations of hydrotreated vacuum gasoil, plant oil, and a mixture of vacuum gasoil and plant oil was studied. The modification with phosphorus was established to decrease the specific surface area and meso- and macropore volumes in HZSM-5 zeolite; the higher phosphorus content, the lower main characteristics of the zeolite porous structure. A decrease in the total acidity of P/HZSM-5 and quantitative redistribution between weak and moderate acid sites also was observed. Testing of the zeolites in catalytic cracking revealed that the phosphorus modification favored an increase in the total yield of propane-propylene and butane-butylene fractions containing olefins in high proportions. Alkali treatment of HZSM-4 zeolite with a high silicate module resulted in a higher silicon extraction and in a considerable increase in the specific surface area of mesopores. In addition, strong acid sites of the zeolite were transformed to weaker ones and/or their exposure changed due to partial silicon removal.

Catalytic hydrogenation of nitrobenzene (NB) is an important technological stage in the production of aniline (AN). The catalytic behavior of hypercrosslinked polystyrene based ruthenium catalyst 3%Ru/MN270 in three-phase hydrogenation of NB to AN is discussed in the paper. The following parameters were varied during the studies: 0.12 to 0.24 mol/L NB, 1.11·10^–4 to 11.12·10^–4 mol/L catalyst, 160 to 190 °C, partial hydrogen pressure of 0.113 to 1.013 MPa. The optimal process parameters were determined to provide 98 % selectivity to aniline at 97 % conversion of nitrobenzene.

The paper deals with the possibility of preparing a mixture of 1,3-dialkylimidazole salts from commercially available reagents via multicomponent condensation. Main factors affecting the yield of the target product, as well as the obtained experimental data needed for scaling-up the process are discussed. It is shown that the prepared mixtures are close in some key properties (viscosity at different temperatures, heat capacity etc.) to the pure salts. The possibility of the application of the prepared salts as solvents for catalytic hydrodechlorination and catalyst components for alkylation of aromatic compounds is demonstrated.

The results of comparative studies of CO₂ hydrogenation over 15% Fe/SiO₂ catalyst under sub- and supercritical conditions are presented for the first time. The reaction was studied at 300–500 °C and atmospheric pressure in gas phase and at 95 atm under supercritical conditions. The molar H₂ : CO₂ ratio was 2 : 1. Under supercritical conditions, the selectivity to CO₂ decreased from 90–95 to 30–50 % at all temperatures, while the selectivity to hydrocarbons increased up to 60 %. The reaction under supercritical conditions, unlike gas-phase hydrogenation, produced alcohols. TG-DTG-DTA techniques were used to demonstrate 2.2-fold decrease in the quantity of carbon-like deposits in comparison to that in the gas-phase reaction. XRD studies revealed the formation of graphite-like species on the catalyst surface under gas-phase but not supercritical conditions. The developed process and catalyst for hydrogenation of CO₂ can be recommended to be further modified in order to improve the catalyst based on iron nanoparticles that is as expensive as 0.1–0.01 of the known catalysts for CO₂ hydrogenation.

Oxidation of diesel fuel was studied using vibro-liquefied and fluidized beds of disperse bank sand in the presence of iron-containing microspheres isolated from flue ash of coal-fired boilers: ferrospheres and cenospheres activated with iron oxide. The obtained results are compared to the available data on oxidation of diesel fuel using microspheres of commercial catalysts for complete oxidation of organic compounds. Deeper oxidation of diesel fuel was observed at 500–600 °C in the presence of ferrospheres and cenospheres bearing iron oxide than in the vibro-liquefied bed of the inert material (bank sand). The most complete oxidation (84.3 %) was observed with ferrospheres at 700 °C. The ferrospheres were used for oxidation of diesel fuel in the fluidized bed of the inert material and they seemed less active under these conditions than the commercial catalysts based on СuСr₂О₄/Аl₂О₃ and disperse Fe₂O₃. Nevertheless, the oxidation rate as high as 97.8 % can be achieved in the presence of ferrospheres by arranging jet fire above the bed. If so, the flame length decreases by half in comparison to the flame above the bed of the inert material. These observations, as well as a decrease in the proportion of CO and unburned carbon in combustion products indicate the catalytic activity of ferrospheres fed to the flame.

The composition and properties of a wide range of domestic and foreign enzyme preparations (EP), used as additives to feeds of farm animals and poultry, are analyzed. The content of the main active enzymes – endoglucanases (beta-glucanases), cellobiohydrolases and xylanases, leading to biocatalytic destruction of non-starch polysaccharides, which are anti-nutritional factors of feeds and causing their incomplete digestion, is determined. It is shown that, based on the data on the component composition and the level of different types of activity, the studied enzyme preparations can be divided into three groups: a) with high xylanase and low cellulase (endoglucanase and cellobiohydrolase) content, b) high cellulase and low xylanase content, c) containing cellobiohydrolases, endoglucanases and xylanases in a different ratio, but without significant predominant of any of these enzymes. The ability of EP to reduce the viscosity of water-soluble non-starch polysaccharides – xylans and beta-glucans- has been studied. Among the enzyme preparations that have xylanase in their composition and belong to groups b) and c), a number of preparations have been determined which, at the same dosage according to xylanase activity, most effectively reduced the viscosity of the aqueous extract of rye containing xylans (Econase XT 25, Agroxyl Plus, Agroxyl Premium, Rovabio Max AP, Sunzyme). It was shown that the xylanase of precisely these EP is not inhibited by protein inhibitors of rye. At the same dosage for beta-glucanase activity, the viscosity of water-soluble beta-glucans of barley was most effectively reduced by the EP Xybeten CELL, Cellulase, Agroxyl, Agrocell, Axtra XB 201, Rovabio Max AP and Vilzyme. For all studied EP, no inhibitory effect of the barley extract on beta-glucanase activity was found.