The review paper deals with analysis of general features of exothermic catalytic reactions over heterogeneous catalysts. Data on studying and arrangement of a number of practically important catalytic reactions are discussed: partial oxidation of hydrocarbons and CO, syntheses of alcohols and hydrocarbons from CO and H₂, hydrocarbon hydrogenation, preferable oxidation of CO. Variations in temperature or concentration of materials fed to the catalyst may result the system in passing through ignition and fading of the catalyst surface by transiting from the low active state to the high active state (external diffusion control regime) and back so that a temperature or concentration hysteresis is observed. The Semenov criterion is used for considering possible temperature profiles established in the catalytic tube reactor during stationary exothermic reaction. The reactors can be classified into isothermic, polytropic, adiabatic depending on the ratio of heat supply and sink rates. The presence of the hot zone shifted to the inlet to the catalyst bed is characteristic of the polytropic reactors. It is emphasized that the temperature profile is influenced by: occurrence of an endothermic reaction along with the exothermic reaction; strong adsorption of one of the reactants; catalyst deactivation. Specific aspects of the reaction transition to the regime of non-isothermic oscillations are considered.

Chemical recycling of polyethylene terephthalate (PET) to produce terephthalic acid (TPA) was studied using in situ hydrolysis with sodium methoxide in methanol and dimethyl sulfoxide (DMSO) as solvent under microwave irradiation. The microwave-assisted reaction was carried out at different temperatures, and reaction time between 5 to 30 min. High degrees of depolymerization were examined at temperature near 70 °C at microwave power 300 W. The reaction was carried out in a sealed microwave reactor in which the time and temperature were controlled and recorded. The products were mainly monomers such as TPA and ethylene glycol (EG) which were isolated and purified for further analysis. Monomethyl terephthalate, dimethyl terephthalate, and terephthalic acid were formed initially then converted to TPA as a single monomer product. Purified, TPA was analyzed and identified by NMR, TGA, DSC and FTIR. It was observed that the reaction greatly depends on the amount of sodium methoxide, the volume of methanol and DMSO used, the reaction time, and temperature. Compared to conventional heating methods, the time needed to achieve complete degradation of PET was significantly reduced to 5 min by using microwave irradiation and sodium methoxide catalyst. This has led to substantial saving in energy and cost supporting thus the conclusion that this proposed recycling process is very beneficial for the recycling of PET wastes.

Theoretical Optimization of the shape of adsorbent granules used for drying hydrocarbon gas streams at a low hydrolytic resistance of the bed was fulfilled. The calculations were based on a two-rate model of gas motion through fixed beds built-up by through-flow particles of various shapes using process parameters typical of drying the associated petroleum gas. A four-spoke ring was shown to be the optimal granule shape, such a granule being 6.154 × 6.154 mm in size at the equivalent size of 3 mm with walls and partitions of 1.026 mm in thickness.

Two types of fine particles of the Geldart class A with different bulk density, ρ_n = 1200 kg/m3 and ρ_n = 1300 kg/m3, were used for experimental studies of the circulating fluidized bed. A bench (0.7 m in diameter and 5.75 m in height) was used for the studies at room temperature with air as the fluidizing gas. The fluidization speed ranged from 0.1 to 0.75 m/s. The bed was sectioned in height using a set of horizontal diffuser grids. Fluctuations in average pressure drops and pressure distribution among the height of the fluidized bed were measured to determine the influence of the particle density on the operating modes of the fluidized bed. The transition rate, U_c, was determined from mean square deviations of pressure drop fluctuations to equal U_c = 0.40 m/s for lighter particles and Uc = 0.35 m/s for heavier particles. The transition rate, Uc, determined from the power energy spectrum of pressure fluctuations was 0.45 and 0.40 m/s for the lighter and heavier particles, respectively. The results of pressure measurements along the bed height showed that the pressure decreased linearly upward the bed, the decrease being faster for the heavier particles than for the lighter particles.

Part 3 of the studies dealt with catalytic properties of the new catalysts based on molylbdenum carbides, resistant to sulfur compounds and providing manufacturing of low pour point diesel fuel with the quality indices identical to those obtained with platinum-containing catalysts. Catalytic properties of bifunctional catalysts 7%Mo2C/SAPO-31 (LCCH-2) and 7%Mo2C/SAPO-11 (LCCH-2-2) for hydroisomerization of diesel fractions were compared at the temperature range between 320 and 400 °C. It was shown that at above 320 °C the catalyst LCCH-2, against LCCCH-2-2, provided the formation of the hydroisomerized diesel fraction at a higher yield and freezing at a lower temperature. Inspection of the data on the ratio of total quantities of monomers and diisomers in the reaction products led to conclude that the former catalyst is more selective than the latter to the formation of terminal monosubstituted alkanes. Studies of the stability of both catalysts to deactivation with coke deposits (100 hour testing at 320 and 360 °C during hydroisomerization) revealed that LCCH-2-2 is less stable to deactivation than LCCH-2. The observed regularities were accounted for by differences in the acidities, degree of homogeneity of distribution of acid and hydrating-dehydrating centers through the catalysts under study, and types of structures of the acid support.

A series of platinum-zeolite based catalysts were prepared by reduction of Pt-salt with a methanol-water mixture using individual HY-zeolite or its modified composites both as protective agents and catalyst supports. The prepared composites have been tested as catalysts in n-C10-hydroconversion reaction in the range of temperature 180–270 °C and at atmospheric pressure. Different parallel and consecutive isomerization and cracking reactions take place in hydroconversion of n-decane over prepared catalysts producing different mono- and multi-isomers and cracked products. The impact of the temperature and conversion degree to the distribution of hydroconversion products has been studied. Special attention was paid to synthesis of high-octane fuel components from n-decane.

The studies were aimed at developing a less expensive and environmentally friendly catalyst than the currently used industrial catalyst CuCr₂O₄/Al₂O₃. CuO-Fe₂O₃-Al₂O₃ systems prepared by fusing the nitrate salts were examined. The mixed oxides were characterized using a set of physicochemical techniques (XRD, XPS, TPR, low-temperature nitrogen adsorption). The catalysts were tested in the reactions of deep oxidationof CO and CH₄ in a flow and circulating flow reactors. The dependence of the activity of Fe₂O₃-Al₂O₃ to oxidation of CO and methane was shown to go through maximum at ca. 18 % of the alumina content. With CuO-Fe₂O₃-Al₂O₃ catalysts, an increase in the copper oxide proportion led to an increase in the catalyst activity to oxidation of CO, there being correlation between the activity and the surface copper concentration. Calcination of CuO-Fe₂O₃-Al₂O₃ at 800 °C for 5 hours resulted in a decrease in the catalytic activity to oxidation of CO due to a decrease in the total specific surface area of the catalyst and to the formation of the phases which are less active to the deep oxidation. Nevertheless, the calcined catalyst CuO-Fe₂O₃-Al₂O₃ competes well with the industrial chromium-containing catalyst CuCr₂O₄/Al₂O₃.

A method of drop molding was suggested for preparation of spherical granules of CuO-Fe₂O₃-Al₂O₃ catalysts. The catalysts were characterized using a set of physicochemical methods and tested for fluidized bed burning of brown coal. The influence of thermal treatment (700 and 800 °C) on the activity, strength and physicochemical properties of the spherical CuO-Fe₂O₃-Al₂O₃ catalyst were studied. The prepared catalyst was shown highly active to oxidation of CO (competitive to that of the currently used industrial catalyst), high crushing and attrition mechanical strength (ca. 10–14 MPa of the minimal crushing strength and 15–23 MPa in average; attrition loss 0.8 % according to ASTM D-4058). Testing of the CuO-Fe₂O₃-Al₂O₃ catalyst for the fluidized bed burning of brown coal demonstrated the attainability of high coal burnout (95 %) characteristic of the industrial catalysts (Shchkz-1, IC-12-73, IC-12-74A), the CO content in flue gas being 600 ppm that was lower of that observed with the industrial iron-containing catalyst IC-12-74A 3,000 ppm) and comparable with the catalyst IC-12-73 (700 ppm).

Recombinant strains Penicillium verruculosum were created which produce homologous endoglucanase 2 (Er2) and heterologous xylanase E (XylE) P. canescens. The recombinant strains were used for preparing new biocatalysts which are enzyme preparations (EP) enriched considerably with Er2 and XylE; the biocatalysts are highly active to plant non-starch polysaccharides (NPS) such as cellulose, β-glucan, xylan. Proteic chromatography was used for determining the qualitative and quantitative composition of the new EP to show that they contain (expressed as proportions of the total protein content) ca. 16–17 % Er2, 48–63 % XylE, 17–30 % cellobiohydrolase, while EP prepared with the recipient strain contained 1.4 % Er2, ca. 60 % cellobiohydrolase and no XylE. pH equal to 4.0 and 5.5 were optimal for the activity to cellulose (with respect to carboxymethylcellulose, CMC) and to xylanase, respectively, EP being active over a wide range of pH from 3 to 7. EP were active to CMC and xylanase at the temperature range from 20 to 80 °C with maxima at 60 and 70 °C. The activity of new EP to xylanase was practically not inhibited by protein inhibitors of rye.