The effect of water-soluble polymers with different structure on the sorption properties of nonregenerable lime sorbents of carbon dioxide was studied. It was found that the introduction of water-soluble polymers into the sorbents could either decrease or increase the protective power time of the sorbents. To explain the revealed regularities, pore structure of the sorbents was investigated, molecular-dynamic modeling of the carbon dioxide transport was performed, and CO₂ diffusion coefficients in water-polymer solutions were calculated. The results of the modeling correlate with the sorption experiment data: a high dynamic sorption capacity of the sorbent is reached after adding a water-polymer medium with a high CO₂ diffusion coefficient. The results obtained can be used both to optimize the systems for the recovery of carbon dioxide from gas mixtures and to intensify mass transfer in the systems intended for photo- and electrocatalytic conversion of CO₂ to useful products.

The effect exerted by the content of metallic (Co-Al₂O₃/SiO₂ catalyst) and acidic (ZSM-5 zeolite in the H-form) components on the properties of bifunctional catalyst for the integrated synthesis of waxy diesel fuel by the Fischer–Tropsch method was studied. Catalysts represented by a composite mixture with a boehmite binder were characterized by XRD, BET and TPR methods. The testing was performed in a flow reactor with a fixed catalyst bed at a pressure of 2.0 MPa, temperature 240 °С and gas hourly space velocity 1000 h^–1. Activity and selectivity of the catalysts as well as the fractional and hydrocarbon composition of the products were investigated in dependence on the ratio of components. It was found that productivity of the synthesis for С₅₊ hydrocarbons and selectivity for the С₁₁–С₁₈ diesel fraction products with a high content of isomeric products correlated with the ratio of metallic and acidic components in the catalysts. The composition of the catalyst recommended for the diesel fuel production has the 1.17 ratio of metallic and acidic components.

Properties of supported Pt-containing granular (Pt/Ce_0.75Zr_0.25O_2–δ) and monolithic structured (Pt/Ce_0.75Zr_0.25O_2–δ /η-Al₂O₃ /FeCrAl) catalysts were studied in the methanol decomposition to syngas for feeding solid oxide fuel cells (SOFC). The application of the monolithic structured catalyst in the methanol decomposition reaction was shown to be promising. The addition of a small oxygen amount to the initial mixture was found to prevent the formation of carbon, thus enhancing the stability of catalyst operation. The proposed monolithic structured catalyst 0.15 wt.% Pt/8 wt.% Ce_0.75Zr_0.25O_2–δ /6 wt.% η-Al₂O₃ /FeCrAl at atmospheric pressure, temperature of ca. 400 °C, feed rate of the reaction mixture 5.6 L/(g_cat·h) and volumetric ratio СН₃ОН/air = 1 can provide the complete conversion of methanol to syngas with the total content of H₂ and СО of ca. 64 vol.% and the syngas output of ca. 6.7 L(Н₂ + СО)/(g_cat· h).

Samples of the powdered catalysts Pd/C and Pd/Ox, which were synthesized by depositing 0.5 and 1.0 wt.% Pd on carbon materials (Sibunit 159k, thermal black Т-900, Vulcan XC-72R) and oxide supports (Ox: γ-Al₂O₃, Cr₂O₃, Ga₂O₃, TiO₂, Ta₂O₅ and V₂O₅, and kieselguhr FW-70), were studied. Their catalytic properties were investigated in the partial hydrogenation of sunflower oil. Comparative testing of the catalysts was performed in the kinetic mode using a static Parr reactor to estimate their activity and trans-isomerization selectivity. The effect of the average size of supported palladium particles (d_CO) on the indicated characteristics in a wide range of d_CO values was discussed.

A wide application of aluminum oxides in the synthesis of heterogeneous catalysts for petrochemistry and oil refining makes it necessary to reveal factors determining the efficiency of the catalytic systems. However, the literature provides no data concerning the effect produced by the amorphous phase in aluminum oxide catalysts on characteristics of the catalytic reaction. Usually the content of amorphous phase is not categorized; however, its presence may significantly deteriorate the catalyst efficiency. X-ray diffraction analysis, low-temperature nitrogen adsorption, electron microscopy and temperature-programmed desorption of ammonia were used in this work to examine samples of the amorphous aluminum oxide obtained from two different precursors. Catalytic properties of the samples were investigated during the vaporphase dehydration of 1-phenylethanol to styrene. It was shown for the first time that the transformation of amorphous aluminum oxide in the catalytic reaction decreased the conversion of alcohol from 84 (for the fresh catalyst) to 64 % (for the regenerated sample). Crystallization of amorphous aluminum oxide by the high-temperature treatment enhanced the catalytic performance, but it did not reach the desired values due to a considerable deterioration of the textural characteristics and acidic properties of the aluminum oxide surface.

The paper is devoted to investigation of the catalytic pyrolysis of high-density polyethylene (PE) in the presence of HBEA, HZSM-5 and HFER catalysts and natural clay. Catalytic pyrolysis of plastic materials is a promising method for treatment of secondary raw materials because it allows converting polymers into chemical compounds, which further serve as a source for chemical industry. Physicochemical parameters of the catalysts were estimated using various methods: IR Fourier spectroscopy, X-ray diffraction analysis, physical adsorption of N₂, thermogravimetric analysis, and pyrolytic gas chromatography. Temperature dependences of PE destruction were obtained as well as the dependence of chemical composition of the catalytic pyrolysis products on the catalyst type. Two main factors were shown to determine the efficiency of cracking and the qualitative composition of products – structural and acidic parameters of the catalyst. The presence of Broensted acid sites in zeolites promoted the cracking and aromatization reactions. The possibility of using the clay sample for thermal decomposition of PE was estimated.

A study on the Pd-catalyzed hydrodebromination of 2,3,4,5-tetrabromothiophene (1) to 3,4-dibromothiophene (2) is reported. The effect of the solvent nature, main agent, temperature and concentration of 1 on the yield of 2 was studied. Optimal conditions of the process were found: a 5 % Pd/Sibunit catalyst constituting 10 % of the substrate weight, a temperature of 80 °С, a pressure of 0.7 MPa, dimethyl formamide with the addition of triethylamine as the main agent in the amount of 2.2 equiv per 1 equiv of the initial substance 1, and the yield of 2 constituting up to 97.5 %. It was shown that the catalyst could be reused with the preservation of the high yield of 2. In comparison with the conventional method of chemical reduction of 1 under the action of zinc in acetic acid, the novel method ensures high output and low wastes.

Catalysts for the second hydrocracking step were tested under different conditions in order to reduce the time of establishing their steadystate activity. The tests were carried out at a laboratory bench under the conditions close to industrial operation and typical of the second hydrocracking step. The introduction of an additional step at the onset of testing with the increased temperature and feed space velocity as well as the use of a dimethyl disulfide solution in decane as a sulfurization mixture were shown to considerably reduce the duration of experiment. Conditions of the preliminary step were selected so as to preserve the catalyst selectivity toward the diesel fraction.