Catalysis and petrochemistry

SnO2-containing catalysts for conversion of monosaccharides to value-added chemical products

2025-12-09T09:12:37+00:00

The article is devoted to the review of scientific works on the use of SnO2-containing mixed oxides as catalysts for the conversion of monosaccharides into value-added chemical products. Fossil feedstocks such as oil, coal, and natural gas, once the dominant sources for fuels and petrochemicals, are being gradually replaced by biomass and waste-derived alternatives. In particular, the study highlights the potential of sugar-based biomass as key renewable feedstocks for the synthesis of high-value-added chemicals. A detailed review is provided on catalytic strategies for biomass conversion, with a focus on heterogeneous acid and bifunctional oxide catalysts containing tin ions. These catalysts demonstrate significant promise due to their thermal stability, reusability, and reduced environmental footprint compared to traditional homogeneous acid systems. The article explores the structural, acidic, and redox properties of tin-containing mixed oxides such as ZrO₂–SiO₂–SnO₂, SnO₂/Al₂O₃, ZnO–SnO₂/Al₂O₃, and CeO₂–SnO₂/Al₂O₃, obtained via sol–gel synthesis or impregnation techniques. Special emphasis is placed on the catalytic role of Lewis and Brønsted acid sites formed by Sn⁴⁺ ions in tetrahedral and octahedral coordination. These active sites enable a variety of key biomass-derived transformations, including dihydroxyacetone conversion to methyl lactate, and selective production of levulinic and formic acids, esters of lactic and glycolic acids from fructose and xylose. Experimental results show high selectivity and yields under mild conditions, confirming the industrial potential of such catalysts. For example, superacid ZrO₂–SiO₂–SnO₂ allow complete fructose conversion to levulinic and formic acids with high yields (at 80÷90 mol. %). The SnO2/Al2O3 catalyst (5 wt. % tin dioxide) in a flow regime converts dihydroxyacetone, the simplest monosaccharide, to methyl lactate (selectivity 90 mol. %). ZnO–SnO₂/Al₂O₃ catalyst with basic and acid centers promotes complete transformation of fructose to alkyl lactates (yields of ethyl and methyl lactates 56 % and 70 % respectively), while bifunctional CeO₂–SnO₂/Al₂O₃ catalyst enable direct transformation of xylose (100 % conversion) with yield of methyl lactate and methyl glycolate in 42 % and 24 % respectively. The multifunctional properties of Sn-containing mixed oxide catalysts - combining acidic, basic, and redox sites - open pathways for cascade reactions and integrated biomass valorization.

Development of a catalyst for the synthesis of motor fuel components from carbon-containing feedstock

2025-12-09T09:12:37+00:00

The article is devoted to the development of an iron-containing catalyst for the synthesis of liquid hydrocarbons over modular units (Fischer-Tropsch process) from synthesis gas obtained by gasification of carbon-containing feedstock. Based on literature data, nine laboratory catalyst samples were synthesized; they differed in both qualitative and quantitative chemical composition as well as in the preparation method. Experimental investigation of the catalytic properties of the synthesized iron-containing catalysts in the Fischer–Tropsch reaction made it possible to select the catalytic composite C3, which served as the basis for designing an original technology for industrial production of an efficient catalyst for the synthesis of liquid hydrocarbons from carbon-containing feedstock, and for producing a pilot batch. The developed industrial catalyst had the following composition: 67.6 % Fe₂O₃, 20.0 % CuO, 2.5 % K₂O, 9.9 % Al₂O₃; the specific surface area of the non-activated catalyst was 24.42 m²/g. This catalyst was characterized using various physicochemical methods, and its catalytic performance was studied in a laboratory unit using a model synthesis-gas mixture. It was shown that, during the Fischer–Tropsch synthesis in the presence of the developed catalyst, iron carbides Fe_xC are formed, with their content ranging from 2.0 to 31 % of the total amount of components. Optimal process conditions were determined, and liquid hydrocarbons were synthesized from synthesis gas using the developed catalyst. It was demonstrated that, under standard conditions (CO:H₂ = 1:3, gas hourly space velocity 2400 h⁻¹, pressure 5 atm, temperature 280 °C), the CO conversion reached 49.8 %, while the yield of liquid hydrocarbons was 0.153 g/(gcat·h), corresponding to a selectivity of 42 % toward liquid hydrocarbons. Successful tests of the developed catalyst were carried out in a pilot unit using synthesis gas produced by wood gasification.

Conversion of glucose into 5-hydroxymethylfurfural on Ukrainian natural zeolites

2025-12-09T09:12:38+00:00

An important product of biomass carbohydrate conversion is 5-hydroxymethylfurfural as a potential raw material component of a wide range of important chemicals. The aim of the work was to study the conversion of glucose into 5-hydroxymethylfurfural in the presence of modified clinoptilolite and mordenite-clinoptilolite zeolite rocks from Transcarpathia. A number of acid catalysts have been synthesized by liquid-phase ion exchange of native cations with calcium, lanthanum, and ammonium cations, as well as by dealumination with hydrochloric and ethylenediaminetetraacetic acid. Their properties were characterized using XRD and XRF analysis, low-temperature nitrogen adsorption/desorption, and FTIR spectroscopy. The acidity of the samples was determined by reverse n-butylamine titration. Acid treatment of the samples contributed to an increase in the specific surface area of the samples by an order of magnitude. The samples were tested in the conversion of 9% aqueous glucose solution into 5-hydroxymethylfurfural. The composition of the reaction products was analyzed by gas chromatography. The glucose conversions and the yields of 5-hydroxymethylfurfural, levulinic acid, and fructose were calculated. The glucose conversions ranged from 30 to 70 %. The results were analyzed in accordance with the characteristics of the nature of the active sites of the catalysts and the porous structure of the latter. It was found that the samples with the presence of Lewis acid sites in the form of extra-framework aluminum and multiply charged cations are characterized by the highest 5-hydroxymethylfurfural yields. Due to glucose conversion occurs mainly on the outer surface of zeolite crystals and at the entrances to the cavities, the polycationic form of clinoptilolite, despite its low porous characteristics, demonstrates the highest yield of 5-hydroxymethylfurfural.

Two component oxide compositions based on TiO2 rutile: ultrasonic treatment, their physicochemical and photocatalytic properties

2025-12-09T09:12:38+00:00

The creation of oxide two-component systems based on TiO₂ rutile was studied. Influence of ultrasound treatment (UST) of these mixtures on their properties was established. The mixtures treatment less influences on the ratio of intensity of (110)/(101) reflexes of TiO₂ what testify any structural change of this oxide but in same time little increase of its particles size was observed. The little increase of the dimension particles for second oxide after UST for the studied mixtures excluding TiO₂/MgO and TiO₂/ZnO was observed. The partial transformation of MgO to Mg(OH)₂ as result of TiO₂/MgO composition treatment was shown which accompanied by decrease of MgO particles size. In the case of TiO₂/ZnO composition the partial destruction of ZnO was observed. The increase of the pores radius after UST with the change of surface element ratio determined by EDX method can testify that strong interaction between oxides takes place. This fact leads to an increase the band gap for the mixture in comparison with initial TiO₂ with its average value between characteristic for TiO₂ and other oxide in mixture. The study of photocatalytic properties of the samples in metronidazole (MN) oxidative decomposition in water shows that for all compositions, excluding TiO₂/ZnO where the activity is connected with more active ZnO in this reaction but not TiO₂, a decrease of initial rate constant K_d was observed. The reduction of rate constant was connected with a decrease of TiO₂ content in the mixtures and introduced value of rate constant determined to quantity of TiO₂ demonstrate its increase in comparison to individual TiO₂.This fact testify the strong interaction in complexes systems between two oxides. Obtained result permits to realize the MN photocatalytic degradation in water with an increase of the complexes catalyst content in reaction mixture what leads to an increase both rate constant and degree of antibiotic transformation. It was established that UST increased the stability of the samples in MN transformation and as result the conversion of MN has more value than in initial mixtures. An increase of degradation degree after UST of the samples correlates with the growth of medium pore radius in result of this treatment what can be connected with an increase of sample surface accessible to UV irradiation. It was shown that obtained composites demonstrate better properties in MN destruction in water in comparison with data known from the literature.

Catalytic properties of reduced graphene oxide deposited on aluminum and magnesium oxides in acetylene hydrogenation

2025-12-09T09:12:39+00:00

The catalytic properties of reduced graphene oxide (rGO) deposited on aluminum and magnesium oxides were investigated in acetylene hydrogenation. Catalysts with different rGO loadings were prepared by impregnating γ-Al₂O₃ and MgO with aqueous graphene oxide suspensions, followed by reduction in hydrogen at 400 °C. The materials were characterized by FTIR, Raman spectroscopy, and SEM. FTIR spectra confirmed the successful deposition of rGO on both supports, and for MgO-based samples, FTIR also revealed partial hydration of surface Mg–O groups, forming Mg(OH)₂ and a hydroxide–graphene interfacial layer that improves anchoring and stabilizes the structure. Raman spectroscopy verified the formation of a graphene-based phase on both oxides and showed that the defect level of the deposited graphene remains constant with varying rGO loading. SEM analysis indicated that on MgO, rGO forms thin film-like structures and irregular folds that create partially covered regions, while on γ-Al₂O₃ it forms continuous films in some areas and isolated folds in others. Modification of γ-Al₂O₃ and MgO with rGO enhanced catalytic activity in acetylene hydrogenation, with the highest rates observed for samples with low rGO content. Both rGO/Al₂O₃ and rGO/MgO exhibited full (100 %) selectivity to ethylene in the 250–400 °C range. The improved performance is attributed to rGO-derived surface structures that ensure effective contact between carbon and oxide phases and facilitate activation of acetylene and hydrogen. Overall, the catalytic behavior of rGO-modified oxides is governed by the acid–base properties of the support and the structural features of the deposited graphene layer, which determine the activation temperature and thermal stability of the system.

Catalytic polymerization of propylene oxide

2025-12-09T09:12:39+00:00

Polyoxypropylene with a molecular weight of one to several thousand is one of the key starting components in the production of polyurethane foams, coatings and adhesives. In industry, polyoxypropylene is traditionally produced by polymerization of propylene oxide (PO) using potassium or sodium hydroxides and low molecular weight hydroxyl initiators, such as glycerol and propylene glycol. The significant number of side processes is the main disadvantage of using alkaline catalysts, which leads to a decrease in the molecular weight of polyoxypropylene. Modern double metal cyanide (DMC) catalysts allow the production of polyols with much higher molecular weights and much lower polydispersity, but they are easily deactivated in the presence of low molecular weight hetero-organic compounds. This paper presents the results of research related to the polymerization process of propylene oxide in the presence of potassium glycerate and subsequent polymerization of PO using the resulting oligomers and DMC catalyst (Arcol® Catalyst 3). The synthesized polyols were analysed by gel permeation chromatography and 13C NMR spectroscopy. For successful initiation of the polymerization process, the optimal molar ratio of the first portion of OP to glycerol initiator is approximately 3:1, and the optimal feed rate of OP per 1 mol of initiator is about 1.5 mol OP per hour. A procedure for obtaining propylene oxide oligomers using potassium glycerate with a given molecular weight in the range Mn = 500-1300 was developed. The synthesis of polyols with Mn > 3000 was carried out using the effective zinc hexacyanocobaltate DMC catalyst Arcol® Catalyst 3. According to 13C NMR spectra of polyols, the two terminal OH groups of glycerol form two polymer chains, the middle OH group of the secondary carbon atom of glycerol does not participate in polymerization.

Conversion of ethanol to n-butanol over copper-containing catalysts with separating product mixture

2025-12-09T09:12:40+00:00

Article presents the results on vapor-phase condensation of ethanol to n-butanol 2СН5ОН = С4Н9ОН + Н2О on the copper-containing catalysts. A sequential two-reactor scheme was applied using the developed supported catalyst for Guerbet reaction in first reactor (245 °C/0.6 MPa) and an industrial Cu-containing catalyst for hydration of the product mixture in second reactor (160 °C/0.6 MPa). Previously, in 2014, the process was tested by us on a pilot instalation with processing of 4 kg of bioethanol per hour. Now we have developed a new Guerbet-supported catalyst and replaced the hydrogenation catalyst.

The main product is n-butanol, the content of which in the hydrogenated product mixture reaches 19 wt. % at ethanol conversion of 30 % in one pass at a catalyst loading of 12 mmol С2Н5ОН/gcat/h. When the catalyst load is doubled, the butanol content decreases to 11 %, but less impurities are formed.

The process of separating the product mixture was simulated using the Aspen HYSYS v12 program and the material and heat balances of the proposed ethanol → butanol process were calculated. The process flow chart includes a reactor unit and 4 separation sections: preliminary separation, separation of light products (ethyl acetate, methyl ethyl ketone), dehydration of recycled ethanol, and a heavy products separation section operating under vacuum. A total the separation scheme includes 15 distillation columns, which can provide the separation of such commercial products as butanol-1, butanol-2, ethyl acetate, butyl acetate, methyl ethyl ketone, butyl butyrate and 2-ethylhexanol with a purity of 99.9 wt. %. A butanol production installation requires a total steam consumption of 8.4 t/t of ethanol, which is equivalent to 630 Nm3/t of natural gas, and electricity of 171 kWh/t of ethanol.

On the mechanism of influence of carbon nanoparticle additives on high-temperature oxidation of diesel fuels

2025-12-09T09:12:40+00:00

The problem of increasing the energy efficiency of liquid motor fuels due to ultra-small amounts of nanoparticles is considered. The relationship between the completeness of fuel combustion in engines and the preliminary liquid-phase oxidation of hydrocarbons in atomized droplets is discussed. High-temperature oxidation at 150 °С with air oxygen of model diesel fuel components in a bubble-type reactor was carried out. The effect of carbon spheroidal nanoclusters on the dynamics of changes in the composition of the liquid phase during oxidation under the same conditions of n-decane and n-dodecane was studied by gas-liquid chromatography. It is shown that the effect of nanoparticles on the conversion of hydrocarbons in a liquid oxidate can vary depending on the proximity of the oxidation process temperature and the boiling point of the liquid. For high-boiling n-dodecane (216 °C) under oxidation conditions at 150 °C, the presence of nanoparticles in the solution slows down the change in the composition of the liquid oxidate. When oxidizing a more low-boiling n-decane (174 °C), nanocluster additives accelerate the reduction of the initial hydrocarbon content in the liquid mass. The obtained results are explained by the simultaneous interaction of hydrocarbon molecules with oxygen in the liquid-phase and gas-phase reaction regions. Carbon nanoclusters inhibit chain reactions of liquid-phase oxidation in the kinetic mode, but activate gas-phase oxidation by accelerating the diffusion stage. Acceleration of diffusion and evaporation of hydrocarbons from the liquid phase is explained by a change in the supramolecular structure of the solution under the influence of nanoparticles with a decrease in viscosity. It is shown that the non-monotonic nature of the change in the viscosity of n-decane from the content of nanoclusters in the solution correlates with the extreme non-monotonic dependence of the energy efficiency of diesel fuel on the concentration of such additives. A possible dependence between the duration of the stages of evaporation of low-boiling components from sprayed droplets and the completeness of combustion of mixed motor fuels is considered.

Chelate complexes of Cu(II) with fluorine-containing ligands: synthesis, structure, antioxidant and antiwear properties

2025-12-09T09:12:41+00:00

Improving the antioxidant and antiwear properties of alternative ethanol-based motor fuels is a pressing problem in petrochemistry. The most rational way to solve this problem is currently considered to be the addition of metal complex compounds in small concentrations to the composition of such fuels. Copper(II) chelates with fluorinated 1,3-diketones, hexafluoroacetylacetone, etc., due to their high volatility and stability, are used in many application areas. However, the use of copper(II) chelate with hexafluoroacetylacetone as an additive to high-tonnage petroleum products (motor fuels and oils) is hindered by the high price of fluorinated 1,3-diketones. The use of fluorinated 1,3-ketoaldehydes, trifluoroacetylacetaldehyde, etc. can solve this problem and increase the stability of such copper(II) chelates. A series of copper(II) chelates with fluorine-containing ligands of different structures was synthesized, their structure and influence on the chemical properties of alternative ethanol-containing motor fuels were investigated. The antioxidant activity of copper(II) chelates was determined by the volumetric method (gasometric setup) on a model reaction of initiated radical-chain oxidation of benzyl alcohol (thermal initiator – 2,2΄-azo-bis-isobutyronitrile, free radical generation rate Wi = 2.98 10–8 М·s–1, temperature – 50±0.2 °C, partial oxygen pressure – 0.02-0.1 MPa). The dependence of the antiwear properties of ethanol solutions on the concentration of copper(II) chelates was evaluated by the change in the bearing capacity (dynamic strength) of the solution according to the ASTM D2783 method on a four-ball tribometer at the critical load value. It was established that the synthesized fluorine-containing copper(II) chelates are inhibitors of the catalytic action of chain breakage in the oxidation of benzyl alcohol, which leads to a long-term inhibition of its oxidation process. The fact of a significant (by 40-65 %) increase in the antiwear properties of ethanol solutions when copper(II) chelates are introduced into their composition in low concentrations of 0.001-0.01 wt. % was revealed. The prospects of using ultra-low concentrations of synthesized metal complexes for improving the chemical properties of alcohol-containing motor fuels were shown.

Lubricants based on synthesised emulsifier-stabilizer

2025-12-09T09:12:41+00:00

Hydroxylated fatty acids were synthesized by epoxidation of unsaturated fatty acids of waste food oil followed by hydrolysis by acylglycerol grouping and oxirane rings. The fatty acid aminoamides of the oils were synthesized by epoxidation of used fooding oil, followed by opening of the oxirane cycle and transamidation of acylglycerols with diethanolamine. The use of lithium soaps of hydroxyacids from waste food oil as an emulsifier-stabilizer, which acts as a lubricant thickener, and the introduction of fatty acid aminoamides of oils as an antioxidant additive into the composition of lubricants made it possible to obtain a plastic (lithium) lubricant. The physicochemical properties of lubricant were investigated and their quality indicators were compared with lubricant based on 12-hydroxystearic acid. The developed lithium lubricant is characterized by improved protective and tribological characteristics, increased stability to oxidation and mechanical stress, does not cause corrosion of non-ferrous metals, and is not inferior to lithium lubricant based on an industrial analog of 12-hydroxystearic acid. The lubricant is intended for friction units of machines and mechanisms. The properties of the resulting lubricant make it possible to predict its long service life in components and mechanisms and the prospects for using the components used in lubricant formulations. On the one hand, these studies make it possible to replace imported components for the production of lubricant thickeners, and on the other hand, to solve the problem of utilization of by-products of oil and fat production.

Microstructure of complex lithium lubricants

2025-12-09T09:12:42+00:00

This work presents the results of studies of the microstructure and properties of lubricant samples based on synthesized complex lithium soaps of hydroxylated fatty acids from of waste food oil as a lubricant thickener. The results of scanning electron microscopy confirmed the differences in the peculiarities of the formation of the structural framework of lubricants depending on their composition, thickener concentration, complexing agents, and heat treatment temperature. It was determined that it is the lubricant thickener that binds the dispersion medium through intermolecular interaction, forms a three-dimensional interwoven microstructure, and gives the lubricant improved rheological and volumetric-mechanical properties. Complex lithium soap is more structured than simple lithium soap, although both are formed by a connected three-dimensional mesh microstructure. It has been shown that the rheological and operational properties of lubricant can be improved by using various complexing agents. The lithium complex lubricant samples are characterized by the maximum thickening effect and have lower effective viscosity values at minus 30 °C. With an increase in the concentration of the thickener, the effective viscosity of lithium complex lubricants increased, but the indicators of mechanical stability and drop point remained almost unchanged. It was found that the optimum heat treatment temperature for complex lithium lubricant is 220 °C. If the heat treatment temperature of the lubricant was exceeded, for example, at 240 °C, the microstructure of the complex lithium soap was destroyed, which led to a deterioration in viscosity and colloidal stability. The established rheological, volume-mechanical, and temperature regularities of the structure formation of the dispersed phase of lubricants can be used to select rational modes of obtaining complex lithium lubricant compositions intended for use in friction units of modern machines and mechanisms.