Key words: hydrargillite, boehmite, transformation in an aqueous medium, solid-phase mobility of the structure, quasi-equilibrium, nucleation, self-adsorbed layer, self-organization
The kinetics of the isothermal transformation of hydrargyllite with a 3.5 microns average particle size into boehmite in the course of autoclave treatment at 160—180 °C has been studied in a liquid water and steam media. Samples of hydrargillite were used with and without the addition of boehmite previously obtained at 200 °C. It was found that when boehmite is added to hydrargillite, the induction period decreases, and the rate of boehmite formation does not change. In a water vapor medium, the induction period is sharply reduced and the rate of boehmite formation increases compared to the process in liquid water. A study of the morphology of the transformation products has shown that the formation and growth of boehmite crystals occurs on the surface of hydrargillite particles. The values of the activation energy 89.3±11.2 kJ/mol and 147.6±11.4 kJ/mol were determined by the temperature dependence of the constants of the isothermal rate of boehmite formation in liquid water and steam, respectively. The mechanism of transformation of hydrargillite into boehmite is discussed.
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ГОСТ
7.0.100-2018
Kinetics of Hydragylite to Boehmite Transformation in Water and Water Vapor / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2025. – Т. 20. – № 4. – С. 79-101. - DOI: 10.34984/SCFTP.2025.20.4.008
TRANSLIT
Inducirovannoe prevrashchenie gidrargillita v byomit v vode i vodyanom pare / – Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2025. – Т. 20. – № 4. – S. 79-101. - DOI: 10.34984/SCFTP.2025.20.4.008
En
Kinetics of Hydragylite to Boehmite Transformation in Water and Water Vapor. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 4, 79-101 (2025). https://doi.org/10.34984/SCFTP.2025.20.4.008
Key words: CaSn(OH)6, CaSnO3, solid-phase mobility, supercritical water fluid, molecular dynamic simulation, DFT
Unlike the traditional hydrothermal method, when the components interact in a solution, under processing a mixture of oxide powders in water vapor or supercritical fluid, the products are formed by solid-phase interaction of the reagents. Treatment of tin and calcium oxides in an autoclave under subcritical water vapour (270 °C) leads to the formation of CaSn(OH)6 crystals, and under supercritical water (400 °C) — to the formation of CaSnO3 crystals. The mechanism of solid-phase mobility during the formation of new phases in water fluid medium is discussed. The interaction of CaSn(OH)6 with water at 25 and 270 °C was simulated by molecular dynamics using DFT calculated potential function.
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ГОСТ
7.0.100-2018
Mechanism of Calcium Stannates Crystallization in Sub- and Supercritical Water Fluid / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2025. – Т. 20. – № 4. – С. 68-78. - DOI: 10.34984/SCFTP.2025.20.4.007
TRANSLIT
Mekhanizm kristallizacii stannata kal'ciya v sub- i sverhkriticheskom vodnom flyuide / – Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2025. – Т. 20. – № 4. – S. 68-78. - DOI: 10.34984/SCFTP.2025.20.4.007
En
Mechanism of Calcium Stannates Crystallization in Sub- and Supercritical Water Fluid. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 4, 68-78 (2025). https://doi.org/10.34984/SCFTP.2025.20.4.007
Key words: supercritical CO2, hydrothermal fractionation, lignin, coconut fiber, extraction
A new approach to fractionation of coconut fiber by the hydrothermal method using ethanol and supercritical (SC) CO2 as co-solvents is proposed. The efficiency of the method for isolating valuable components due to the synergistic effect of hydrothermal treatment and increased solubility of biomass in the ethanol—water—SC CO2 system is demonstrated. During the 15 minute treatment at 110 °C, 12 MPa, and a fiber-to-ethanol mass ratio of 1 : 20, the maximum lignin yield (65 %) was reached, which is more than 2 times higher than during hydrothermal extraction with ethanol addition (26 %). The conservation of carbonyl groups and the native ratio of G (guaiacil) and S (syringyl) structural units in isolated lignin in accordance with the literature data has been shown by IR- and NMRspectroscopy.
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ГОСТ
7.0.100-2018
Hydrothermal Extraction of Coconut Fiber Components in the Presence of Ethanol and Supercritical Carbon Dioxide / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2025. – Т. 20. – № 4. – С. 57-67. - DOI: 10.34984/SCFTP.2025.20.4.006
TRANSLIT
Gidrotermal'naya ekstrakciya komponentov kokosovogo volokna v prisutstvii etanola i sverhkriticheskogo dioksida ugleroda / – Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2025. – Т. 20. – № 4. – S. 57-67. - DOI: 10.34984/SCFTP.2025.20.4.006
En
Hydrothermal Extraction of Coconut Fiber Components in the Presence of Ethanol and Supercritical Carbon Dioxide. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 4, 57-67 (2025). https://doi.org/10.34984/SCFTP.2025.20.4.006
Key words: supercritical fluid, solubility of supercritical fluid in hydrocarbons, empirical dependence, equation of state
A method is proposed for describing the solubility of supercritical fluids in hydrocarbons using empirical parameters determined by the error function minimization method. The solubility of supercritical CO2 in cyclohexane and kerosene at 313 K at various pressures is calculated. The standard deviation of the calculated data from the experimental ones according to the proposed method was no more than 8.2%.
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ГОСТ
7.0.100-2018
Description of the Solubility of Supercritical Fluid in Hydrocarbons over a Wide Range of Pressures and Temperatures / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2025. – Т. 20. – № 4. – С. 50-56. - DOI: 10.34984/SCFTP.2025.20.4.005
TRANSLIT
Opisanie rastvorimosti sverhkriticheskogo flyuida v uglevodorodah v shirokom intervale davlenij i temperatur / – Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2025. – Т. 20. – № 4. – S. 50-56. - DOI: 10.34984/SCFTP.2025.20.4.005
En
Description of the Solubility of Supercritical Fluid in Hydrocarbons over a Wide Range of Pressures and Temperatures. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 4, 50-56 (2025). https://doi.org/10.34984/SCFTP.2025.20.4.005
Key words: palladium, hexafluoroacetylacetonate, supercritical carbon dioxide, transition metals, catalysts, silica gel, acetylene, hydrogenation, selectivity
The kinetics of acetylene hydrogenation in the presence of supported catalysts containing transition metals (Fe, Co, Ni, Cu, Ag) and palladium was studied. The catalysts were prepared by deposition of palladium hexafluoroacetylacetonate from its solution in supercritical carbon dioxide onto a silica-based support, followed by heat treatment and reduction in a hydrogen flow at 500 °C. The support was pre-impregnated with solutions of transition metal nitrates. The catalytic properties of the bimetallic systems were compared with monometallic systems containing the same components. The mutual influence of palladium and the transition metal on their catalytic properties was demonstrated. A change in the kinetics of the formation of acetylene hydrogenation products (ethylene and methane) with increasing temperature was revealed, manifesting itself differently on bimetallic catalysts containing Cu and Ag and on Fe-, Co-, and Ni-containing catalysts. In the second case, a minimum acetylene conversion rate is observed at temperatures around 100 °C, while the selectivity for ethylene formation increases sharply at further temperature rise. The observed patterns are interpreted from the point of view of the existence on the surface of complex multicomponent catalytic systems of various forms of adsorption of reactants (hydrogen and unsaturated hydrocarbons), differing in adsorption strength and reactivity.
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ГОСТ
7.0.100-2018
Catalytic Properties of Silica-Supported Monometallic and Palladium-Containing Bimetallic Catalysts in Selective Hydrogenation of Acetylene / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2025. – Т. 20. – № 4. – С. 34-49. - DOI: 10.34984/SCFTP.2025.20.4.004
TRANSLIT
Kataliticheskie svojstva nanesennyh na oksid kremniya monometallicheskih i soderzhashchih palladij bimetallicheskih katalizatorov v reakcii selektivnogo gidrirovaniya acetilena / – Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2025. – Т. 20. – № 4. – S. 34-49. - DOI: 10.34984/SCFTP.2025.20.4.004
En
Catalytic Properties of Silica-Supported Monometallic and Palladium-Containing Bimetallic Catalysts in Selective Hydrogenation of Acetylene. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 4, 34-49 (2025). https://doi.org/10.34984/SCFTP.2025.20.4.004
Key words: carbon dioxide, hydrogenation, hydrocarbons, olefins, CO2 reduction, ironcontaining catalyst, potassium, Fischer—Tropsch synthesis
The regularities of carbon dioxide hydrogenation on a Fe-containing catalyst supported on a carbon carrier was studied in the temperature range of 250—400 °C at a pressure of 0.1 and 8.5 MPa. During the CO2 hydrogenation at 0.1 MPa, only CO is formed. At 8.5 MPa, a deeper hydrogenation of CO2 occurs with hydrocarbons formation (the value of the chain growth probability coefficient α = 0.54—0.65), the selectivity to which increases with increasing temperature. The best results for hydrocarbon formation were obtained at 8.5 MPa and 400 °C, with the C2—C4 olefin-to-alkane ratio reaching 1.6.
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ГОСТ
7.0.100-2018
Effect of Pressure on CO2 Hydrogenation on a Catalyst Containing Iron on a Carbon Support / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2025. – Т. 20. – № 4. – С. 26-33. - DOI: 10.34984/SCFTP.2025.20.4.003
TRANSLIT
Vliyanie davleniya na gidrirovanie CO2 na katalizatore, soderzhashchem zhelezo na uglerodnom nositele / – Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2025. – Т. 20. – № 4. – S. 26-33. - DOI: 10.34984/SCFTP.2025.20.4.003
En
Effect of Pressure on CO2 Hydrogenation on a Catalyst Containing Iron on a Carbon Support. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 4, 26-33 (2025). https://doi.org/10.34984/SCFTP.2025.20.4.003
Key words: supercritical fluid chromatography, enantiomers, chiral separation, semipreparative separation methods, analytical separation methods, ibuprofen, ketoprofen
Highly efficient analytical methods for separating racemic mixtures of ibuprofen and ketoprofen with supercritical fluid chromatography (SFC) have been developed using a chiral stationary phase based on amylose and supercritical carbon dioxide in combination with a co-solvent as a mobile phase. Optimum values of the resolution and selectivity for each pair of enantiomers have been achieved both in the isocratic and gradient modes. It has been revealed that the separation efficiency significantly depends on the co-solvent content in the mobile phase. The possibility of scaling the developed methods for semipreparative analysis has been assessed.
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ГОСТ
7.0.100-2018
Development of a Semi-Preparative Method for Chiral Separation of Ibuprofen and Ketoprofen Racemic Mixtures by Supercritical Fluid Chromatography / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2025. – Т. 20. – № 4. – С. 20-25. - DOI: 10.34984/SCFTP.2025.20.4.002
TRANSLIT
Razrabotka polupreparativnogo sposoba hiral'nogo razdeleniya racemicheskih smesej ibuprofena i ketoprofena metodom sverhkriticheskoj flyuidnoj hromatografii / – Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2025. – Т. 20. – № 4. – S. 20-25. - DOI: 10.34984/SCFTP.2025.20.4.002
En
Development of a Semi-Preparative Method for Chiral Separation of Ibuprofen and Ketoprofen Racemic Mixtures by Supercritical Fluid Chromatography. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 4, 20-25 (2025). https://doi.org/10.34984/SCFTP.2025.20.4.002
Key words: aerogel, germanium oxide, doping, praseodymium, co-gelation, luminescence
A straightforward method for creating crystalline GeO2: Pr3+ aerogels is introduced. By adapting an existing epoxide-induced synthesis process, we successfully performed cogelation of GeCl4 and Pr(NO3)3 · 5H2O. It was shown show that the concentration of the dopant ion in the aerogel increases in direct proportion to its initial share in the mixture, with a uniform distribution throughout the material. The dependence of the photoluminescence of GeO2: Pr3+ aerogels on the excitation wavelength is established. At high excitation energies, the luminescence is completely determined by the germanium oxide matrix, while when excited by green light, the characteristic orange-red emission bands of Pr3+ ions become the dominant.
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ГОСТ
7.0.100-2018
Co-Hydrolysis of GeCl4 and Pr(NO3)3 · 5H2O in an Aprotic Solvent — a Way to Create Aerogels with Target Luminescent Characteristics / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2025. – Т. 20. – № 4. – С. 3-19. - DOI: 10.34984/SCFTP.2025.20.4.001
TRANSLIT
Sovmestnyj gidroliz GeCl4 i Pr(NO3)3 · 5H2O v aprotonnom rastvoritele — put' k sozdaniyu aerogelej s zadannymi lyuminescentnymi harakteristikami / – Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2025. – Т. 20. – № 4. – S. 3-19. - DOI: 10.34984/SCFTP.2025.20.4.001
En
Co-Hydrolysis of GeCl4 and Pr(NO3)3 · 5H2O in an Aprotic Solvent — a Way to Create Aerogels with Target Luminescent Characteristics. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 4, 3-19 (2025). https://doi.org/10.34984/SCFTP.2025.20.4.001
Key words: supercritical fluid extraction, moss, Polytrichum commune, biologically active substances
The leafy moss Common Haircap (Polytrichum commune) is widespread in nature, actively used in folk medicine and is a promising renewable raw material for obtaining valuable biologically active substances. In this study, a method for extracting lipophilic secondary metabolites from P. commune biomass using supercritical fluid extraction with a mixture of carbon dioxide and acetone (9 : 1) is proposed. The implementation of an experimental design with varying temperature, pressure and duration of extraction made it possible to establish optimal process conditions to achieve maximum values of the yield of extractive substances (> 1.5 %), the total polyphenolics content and antioxidant activity. According to a high-performance liquid chromatography — high-resolution mass spectrometry analysis, the main constituents of the obtained extracts were stilbene flavonone communin A, diterpenoids and pentacyclic triterpenoids, polyunsaturated fatty acids and pheophytin A, which possess high antioxidant and biological activity.
doi:10.34984/SCFTP.2025.20.2.007
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ГОСТ
7.0.100-2018
Supercritical Fluid Extraction of Bioactive Ccompounds from Polytrichum commune moss Biomass / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2025. – Т. 20. – № 2. – С. 71-89. - DOI: 10.34984/SCFTP.2025.20.2.007
TRANSLIT
Sverhkriticheskaya flyuidnaya ekstrakciya biologicheski aktivnyh veshchestv iz biomassy mha Polytrichum commune / – Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2025. – Т. 20. – № 2. – S. 71-89. - DOI: 10.34984/SCFTP.2025.20.2.007
En
Supercritical Fluid Extraction of Bioactive Ccompounds from Polytrichum Commune moss Biomass. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 2, 71-89 (2025). https://doi.org/10.34984/SCFTP.2025.20.2.007
Key words: supercritical carbon dioxide, polymer modification, urethane formation reaction
In a supercritical carbon dioxide (SC-CO2), methacrylate derivatives of methoxypolyethyleneglycol (mPEG, 5 kDa) were synthesized via the urethane formation reaction. It was shown that the use of SC-CO2 allows to effectively carry out the reaction both in two stages (the first stage is to obtain the isocyanate derivative, the second stage is to obtain the methacrylate derivative of mPEG) and to combine the two stages into one. The effect of the reagent ratio and reaction conditions on the composition of the reaction products was studied. It was shown that carrying out the reaction in two stages allowed to obtain the methacrylate derivative of mPEG with a yield of up to 80 %. In this case, the production of the isocyanate derivative of polyester and the addition of methacrylate fragments were carried out at different parameters of the SC-CO2: the isocyanate group was introduced under «harsh conditions» (65 °C, 20—24 MPa), and the introduction of the methacrylate group occurred under «soft conditions» (40 °C, 12—13 MPa). Polymerization of the obtained monomers was carried out with the production of spatially cross-linked systems based on both individual modified mPEG and its compositions with metaclylated polylactide (PLA). Such systems can be further used as matrices for cell immobilization and the creation of implants.
doi:10.34984/SCFTP.2025.20.2.006
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ГОСТ
7.0.100-2018
Aliphatic Polyesters Modified in Supercritical Carbon Dioxide as Polymerizable Materials for Implants / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2025. – Т. 20. – № 2. – С. 59-70. - DOI: 10.34984/SCFTP.2025.20.2.006
TRANSLIT
Modificirovannye v srede sverhkriticheskogo dioksida ugleroda alifaticheskie poliefiry kak polimerizacionno-sposobnye materialy dlya polucheniya implantatov / – Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2025. – Т. 20. – № 2. – S. 59-70. - DOI: 10.34984/SCFTP.2025.20.2.006
En
Aliphatic Polyesters Modified in Supercritical Carbon Dioxide as Polymerizable Materials for Implants. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 2, 59-70 (2025). https://doi.org/10.34984/SCFTP.2025.20.2.006
Key words: supercritical antisolvent, crystallization, morphology
The study investigates the dependence of the size and morphology of salbutamol sulfate particles preci pitated by supercritical antisolvent preci pitation (SAS) on the pressure and concentration of the micronized substance in solution. It is shown that micronization by the SAS method from single-phase and two-phase methanol—CO2—salbutamol sulfate systems results in the production of amorphous spherical particles and crystalline particles elongated in one direction, respectively. When the process is carried out from a singlephase system, particles of significantly smaller size are observed compared to those obtained from the two-phase region. Additionally, during micronization from both two-phase and single-phase systems, different dependences of particle size on the concentration of salbutamol in the solution are observed using the SAS method. The main reason for these differences is related to the mechanisms of mixing of the solvent with the solution. In the case of a two-phase system, crystallization occurs in droplets, which have a significantly higher proportion of solvent compared to a single-phase system. This leads to a lower local degree of supersaturation.
doi:10.34984/SCFTP.2025.20.2.004
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ГОСТ
7.0.100-2018
Micronization of Salbutamol Sulfate by Supercritical Antisolvent Precipitation from Single-phase and Two-phase CO2—Metanol Mixtures / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2025. – Т. 20. – № 2. – С. 35-44. - DOI: 10.34984/SCFTP.2025.20.2.004
TRANSLIT
Mikronizaciya sul'fata sal'butamola metodom sverhkriticheskogo antisol'ventnogo osazhdeniya iz odnofaznoj i dvuhfaznoj smesej CO2—metanol / – Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2025. – Т. 20. – № 2. – S. 35-44. - DOI: 10.34984/SCFTP.2025.20.2.004
En
Micronization of Salbutamol Sulfate by Supercritical Antisolvent Precipitation from Single-phase and Two-phase CO2—Metanol Mixtures. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 2, 35-44 (2025). https://doi.org/10.34984/SCFTP.2025.20.2.004
Key words: supercritical antisolvent, morphology, crystallization, solubility
A new method for measuring the solubility of multicomponent fluids, based on a combination of supercritical antisolvent preci pitation and UV-spectroscopy (SAS—UFS), was proposed. Using acetylsalicylic acid as an example, the results of the solubility measurements obtained using this method were compared with literature data. The data on the solubility of acetylsalicylic acid obtained using the SAS—UFS technique are generally consistent with literature values: the order of values is the same under all conditions. In most cases, the values obtained using the SAS—UFS technique fall within the range of values obtained using other methods, such as the dynamic method and SAS—SFC (combination of supercritical antisolvent precipitation and supercritical fluid chromatography). These results indirectly indicate the accuracy of the data obtained.
doi:10.34984/SCFTP.2025.20.2.003
Key words: photocatalysis, oxidation, sulfides, quinones, supercritical carbon dioxide
Quinizarin was first used as a photocatalyst for the oxidation of organic compounds with molecular oxygen in a supercritical carbon dioxide (SC-CO2) medium under the visible light irradiation. The choice of the catalyst was justified by the availability and high efficiency of quinizarin in comparison with structurally similar derivatives of anthraquinone: 2-nitro-1,4-dihydroxyanthraquinone and 2,3-diamino-1,4-dihydroxyanthraquinone. Carrying out photocatalytic synthesis of sulfoxides and sulfones via oxidation of organic sulfides with molecular oxygen in a SC-CO2 medium allows to reduce its fire hazard and make it environmentally benign.
doi:10.34984/SCFTP.2025.20.2.002
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ГОСТ
7.0.100-2018
Quinizarin – an Effective Photocatalyst for Oxidation of Organic Sulfides in a Supercritical Carbon Dioxide Medium / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2025. – Т. 20. – № 2. – С. 45-58. - DOI: 10.34984/SCFTP.2025.20.2.002
TRANSLIT
Hinizarin – effektivnyj fotokatalizator okisleniya organicheskih sul'fidov v srede sverhkriticheskogo dioksida ugleroda / – Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2025. – Т. 20. – № 2. – S. 45-58. - DOI: 10.34984/SCFTP.2025.20.2.002
En
Quinizarin – an Effective Photocatalyst for Oxidation of Organic Sulfides in a Supercritical Carbon Dioxide Medium. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 2, 45-58 (2025). https://doi.org/10.34984/SCFTP.2025.20.2.002
Key words: supercritical drying, aerogel, gel formation, stepwise solvent replacement, conceptual design, mathematical modeling
A software package has been developed in the Python programming language for the conceptual design of a process flow diagram for producing chitosan aerogel particles. The software package covers the calculation of the entire production chain, including the stages of solution preparation, gelation, solvent replacement in the gel pores, and supercritical drying. The structure of the package includes a mathematical model of flow hydrodynamics in a receiving tank, a model of diffusion mass transfer in the porous structure of chitosan gel particles, a material balance calculation, an equipment parameter calculation unit, and a technical and economic assessment subsystem. Using the software package, the user can determine the optimal parameters for the process of producing chitosan aerogel particles and create a preliminary process flow diagram for the production process adapted to the specified constraints. The software package is designed to scale the technology for producing chitosan aerogel particles and calculate the cost of production at various productivity levels.
doi:10.34984/SCFTP.2025.20.2.002
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ГОСТ
7.0.100-2018
Software Package for Conceptual Design of Processes for Obtaining Chitosan Aerogels Particles / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2025. – Т. 20. – № 2. – С. 14-23. - DOI: 10.34984/SCFTP.2025.20.2.002
TRANSLIT
Programmnyj kompleks dlya konceptual'nogo dizajna processov polucheniya chastic hitozanovyh aerogelej / – Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2025. – Т. 20. – № 2. – S. 14-23. - DOI: 10.34984/SCFTP.2025.20.2.002
En
Software Package for Conceptual Design of Processes for Obtaining Chitosan Aerogels Particles. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 2, 14-23 (2025). https://doi.org/10.34984/SCFTP.2025.20.2.002
Key words: supercritical water oxidation, aluminum oxide, structural changes
The results of an experimental study of aluminum oxidation with sub- and supercritical water in the range of 350—410 °C for 60—300 min are presented. It is shown that aluminum hydroxides and oxides with a developed surface are formed as a result of oxidation. A non-monotonic dependence of the specific surface area of the oxidation products on the process temperature is revealed, caused by the formation of various compounds and phases of aluminum oxide. Calcination of the oxidation products at 550 °C leads to the formation of γ-, χ- and α-phases of Al2O3 in a ratio determined by the temperature and time of oxidation in a water fluid.
doi:10.34984/SCFTP.2025.20.2.001
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ГОСТ
7.0.100-2018
Effect of Temperature and Time of Aluminum Oxidation in Sub- and Supercritical Water on Composition and Textural Characteristics of Solid Oxidation Products / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2025. – Т. 20. – № 2. – С. 4-13. - DOI: 10.34984/SCFTP.2025.20.2.001
TRANSLIT
Vliyanie temperatury i vremeni okisleniya alyuminiya v srede subi sverhkriticheskoj vody na sostav i teksturnye harakteristiki tverdyh produktov okisleniya / – Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2025. – Т. 20. – № 2. – S. 4-13. - DOI: 10.34984/SCFTP.2025.20.2.001
En
Effect of Temperature and Time of Aluminum Oxidation in Sub- and Supercritical Water on Composition and Textural Characteristics of Solid Oxidation Products. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 2, 4-13 (2025). https://doi.org/10.34984/SCFTP.2025.20.2.001
Key words: polymeric membranes, gas separation, 1,2-disubstituted polyacetylenes, CO2 capture, chemical modification of polymers, ionic liquids
This study focuses on the chemical modification of a polymer promising for gas separation membranes to enhance its CO2 selectivity. The possibility of introducing butylimidazolium bromide (BIm+Br-) into the structure of poly(1-trimethylsilyl-1-propyne) (PTMSP) via a two-step process was demonstrated: bromination of the initial polymer with N-bromosuccinimide followed by reaction with a tertiary amine—N-butylimidazole. Supercritical CO2 and CHF3 were used as reaction media, offering advantages over organic solvents, such as non-toxicity, non-flammability, and environmental safety. Depending on the process conditions, the proposed method allows for tuning the BIm+Br- content in the polymer structure. The obtained modified polymers exhibit good film-forming properties, thermal stability, and enhanced resistance to aliphatic, alicyclic, halogenated, and aromatic hydrocarbons. It was found that increasing the BIm+Br- content in the polymer improves the selectivity of CO2/N2 and CO2/CH4 separation while maintaining high gas permeability. These results open new possibilities for designing efficient membrane materials for industrial gas separation applications.
doi:10.34984/SCFTP.2025.20.1.007
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ГОСТ
7.0.100-2018
Chemical Modification of Poly(1-Trimethylsilyl-1-Propyne) in Supercritical Fluid Media for the Development of High-Performance Membrane Materials / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2025. – Т. 20. – № 1. – С. 81-94. - DOI: 10.34984/SCFTP.2025.20.1.007
TRANSLIT
Himicheskaya modifikaciya poli(1-trimetilsilil-1-propina) v srede sverhkriticheskih flyuidov dlya sozdaniya vysokoeffektivnyh membrannyh materialov / – Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2025. – Т. 20. – № 1. – S. 81-94. - DOI: 10.34984/SCFTP.2025.20.1.007
En
Chemical Modification of Poly(1-Trimethylsilyl-1-Propyne) in Supercritical Fluid Media for the Development of High-Performance Membrane Materials. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 1, 81-94 (2025). https://doi.org/10.34984/SCFTP.2025.20.1.007
Key words: molecular descri ptor, supercritical carbon dioxide, solubility, method QSPR, software and analytical complex, database
Mathematical models of the solubility of various groups of organic substances in supercritical carbon dioxide are proposed. The developed models are based on the quantitative structure-property ratio method. The key feature of the method is to obtain the relationship between the predicted property and the structure of the substance molecule (molecular descri ptors). As part of the work, molecular descri ptors affecting solubility were selected and dependences of the solubility of organic substances in supercritical carbon dioxide were obtained using the multiple linear regression method. The models were developed using a developed software and analytical complex and an original database containing information on the solubility of substances in supercritical carbon dioxide and information on the molecular descri ptors of soluble substances. The predictive ability of the developed models was evaluated using training and test samples of experimental data on the solubility of substances in supercritical carbon dioxide at various pressure and temperature parameters. Based on the results obtained, it was concluded that the developed models are promising for predicting the solubility of substances in supercritical carbon dioxide.
doi:10.34984/SCFTP.2025.20.1.006
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ГОСТ
7.0.100-2018
Modeling of Solubility of Organic Substances in Supercritical Carbon Dioxide / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2025. – Т. 20. – № 1. – С. 66-80. - DOI: 10.34984/SCFTP.2025.20.1.006
TRANSLIT
Modelirovanie rastvorimosti organicheskih veshchestv v sverhkriticheskom diokside ugleroda / – Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2025. – Т. 20. – № 1. – S. 66-80. - DOI: 10.34984/SCFTP.2025.20.1.006
En
Modeling of Solubility of Organic Substances in Supercritical Carbon Dioxide. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 1, 66-80 (2025). https://doi.org/10.34984/SCFTP.2025.20.1.006
Key words: aerogels, silica, dimethyl sulfoxide, transparency, modification
Dimethyl sulfoxide (DMSO) is proposed as a solvent at the gelation stage during the synthesis of transparent aerogels based on tetramethyl orthosilicate and 3-aminopropyltrimethoxysilane (APTMS). The transparency of the aerogels varied depending on the content of the aminopropyl fragment. The textural characteristics of the aerogels were studied. It was shown that the use of DMSO instead of isopropanol, a standard solvent for the synthesis of gels, allows one to significantly increase the specific surface area of the aerogels. Using DMSO as a solvent, transparent aerogels based on APTMS and modified with fragments of perfluorononanoic acid and L-phenylalanine were obtained. The possibility of obtaining transparent aerogels containing amino complexes of transition metals, namely copper and palladium, was demonstrated.
doi:10.34984/SCFTP.2025.20.1.005
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ГОСТ
7.0.100-2018
Synthesis of Transparent Amino-Modified SiO2 Aerogels and their Derivatives / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2025. – Т. 20. – № 1. – С. 55-65. - DOI: 10.34984/SCFTP.2025.20.1.005
TRANSLIT
Sintez prozrachnyh amino-modificirovannyh SiO2 aerogelej i ih proizvodnyh / – Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2025. – Т. 20. – № 1. – S. 55-65. - DOI: 10.34984/SCFTP.2025.20.1.005
En
Synthesis of Transparent Amino-Modified SiO2 Aerogels and their Derivatives. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 1, 55-65 (2025). https://doi.org/10.34984/SCFTP.2025.20.1.005
Key words: supercritical lower alcohols, methanol, bornyl acetate, borneol, fir needle oil, transesterification reaction
A non-catalytic transesterification (alcoholysis) reaction of bornyl acetate in commercial fir needle oil has been carried out for the first time using supercritical lower alcohols - methanol, ethanol and isopropanol. Only the use of methanol is shown to provide high conversion and selectivity of the reaction. Thus, at 350 °C for 1 hour of reaction in autoclave-type reactor 93 % selectivity on borneol with 90 % conversion of bornyl acetate was achieved. A further increase in reaction time leads to a decrease in borneol selectivity, accompanied by an unexpected increase in camphor concentration.
doi:10.34984/SCFTP.2025.20.1.004
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ГОСТ
7.0.100-2018
Supercritical Alcoholysis of Bornyl Acetate in Fir Needle Oil for the Production of Borneol / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2025. – Т. 20. – № 1. – С. 42-54. - DOI: 10.34984/SCFTP.2025.20.1.004
TRANSLIT
Alkogoliz bornilacetata pihtovogo masla v sverhkriticheskih usloviyah dlya polucheniya borneola / – Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2025. – Т. 20. – № 1. – S. 42-54. - DOI: 10.34984/SCFTP.2025.20.1.004
En
Supercritical Alcoholysis of Bornyl Acetate in Fir Needle Oil for the Production of Borneol. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 1, 42-54 (2025). https://doi.org/10.34984/SCFTP.2025.20.1.004
Key words: supercritical fluids, density, fibre-optic densitometer, CO2 hydrogenation, phenol conversion
The dependences of the reaction mixture density on temperature are analyzed for the following processes: 1) catalytic hydrogenation of CO2; 2) conversion of phenol and cyclohexanol in sub- and supercritical water. The density measurements were performed using «Lazerokhim» fiber-optic densitometer. The state of the waveguide end face surface after measurements at elevated temperature was analyzed using scanning electron microscopy (SEM). It was found that for non-aqueous reaction mixtures, the laser-optical method of density monitoring is applicable in a wide range of temperatures and pressures. In the case of water and water-organic mixtures, correct determination of the densities is possible only at temperatures of 25—190°C, since an increase in temperature above 200°C leads to irreversible etching of the silicate optical waveguide end face surface by water-containing fluid.
doi:10.34984/SCFTP.2025.20.1.003
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ГОСТ
7.0.100-2018
Experience of Using the «Lazerochim» Densitometer to Determine the Densities of Water-Organic Reaction Media / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2025. – Т. 20. – № 1. – С. 27-41. - DOI: 10.34984/SCFTP.2025.20.1.003
TRANSLIT
Opyt ispol'zovaniya densitometra «Lazerohim» dlya opredeleniya plotnostej vodno-organicheskih reakcionnyh sred / – Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2025. – Т. 20. – № 1. – S. 27-41. - DOI: 10.34984/SCFTP.2025.20.1.003
En
Experience of Using the «Lazerochim» Densitometer to Determine the Densities of Water-Organic Reaction Media. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 1, 27-41 (2025). https://doi.org/10.34984/SCFTP.2025.20.1.003