Key words: supercritical fluid extraction; shrinking core model; multicomponent extract; Maxwell—Stefan approach
The paper presents a model of supercritical fluid extraction of plant triglycerides from seeds of high-oil raw material. Oil is considered in a two-component approximation. A three-component solution with CO2 is described within the framework of the theory of regular solutions. The sign of the interaction energy of the molecules of the oil components makes it possible to distinguish between two thermodynamic equilibrium modes. Mass transfer through the transport channels of an individual particle is described within the framework of the shrinking core model. Constitutive relations between diffusion fluxes and gradients of chemical potentials are formulated within the framework of the Maxwell— Stefan approach. Each component of the oil has its own front and a pair of shrinking core/transport zone. It is shown that the concentration profiles of the oil components are determined not only by diffusion processes, as is typical in the framework of the one-component approximation, but also by the material two-phase equilibrium of individual components.
doi:10.34984/SCFTP.2023.19.1.001
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ГОСТ
7.0.100-2018
Model of supercritical fluid extraction of vegetable oil in two-component approximation / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2024. – Т. 19. – № 1. – С. 3-16. - DOI: 10.34984/SCFTP.2023.19.1.001
TRANSLIT
Model sverhkriticheskoj flyuidnoj ekstrakcii rastitelnogo masla v dvuhkomponentnom priblizhenii / – Tekst : neposredstvennyj // Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2024. – Т. 19. – № 1. – S. 3-16. - DOI: 10.34984/SCFTP.2023.19.1.001
En
Model of supercritical fluid extraction of vegetable oil in two-component approximation. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 1, 3-16 (2024). https://doi.org/10.34984/SCFTP.2023.19.1.001
Key words: saturation line, density, sulfur hexafluoride, order parameter, rectilinear diameter
Information on the behavior of the SF6 density on the binodal in the asymptotic vicinity of the critical point 3·10-6 < τ < 2 · 10 -4, where τ = (Tc - T)/Tc , — relative temperature is presented. The densities of the liquid (ρl) and vapor (ρg) phases were calculated based on the experimental data of Garrabos et al. (2018) about the height h at which the meniscus is located separating the two phases of the sample in a horizontal cell with a diameter d at a temperature T under conditions of Earth gravity. As the second component of the method, the order parameter fs(τ) is considered in analytical form, which corresponds to the scale theory (ST) of critical phenomena and is based on (ρl, ρg,T -data from Funke et al. (1998) for SF6 in the range 10-3 < τ <0,3. Several problems are formulated, including the construction of dependencies ρl(τ) и ρg(τ), corresponding to ST and correlating with (h,T)-data for 10-6 < τ < 10-3. The relationship between (h,T) data and the functions fs(τ) и fd(τ) (where fd is the average or rectilinear diameter) is investigated. The dependences of ρl(τ) and ρg(τ) on temperature in the range 10-6 < τ < 10-3 were calculated. The dependences ρl(τ) and ρg(τ) that correspond to ST and working satisfactorily in the range 10-6< τ < 10-3 were constructed.
doi:10.34984/SCFTP.2023.19.1.002
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ГОСТ
7.0.100-2018
Adaptation of (<i>h,T</i>)-data to calculate some</span> thermodynamic properties of SF<sub>6</sub> on saturation curve / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2024. – Т. 19. – № 1. – С. 17-29. - DOI: 10.34984/SCFTP.2023.19.1.002
TRANSLIT
Adaptaciya (<i>h,T</i>)-dannyh dlya rascheta nekotoryh termodinamicheskih svojstv SF<sub>6</sub> na krivoj nasyshcheniya / – Tekst : neposredstvennyj // Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2024. – Т. 19. – № 1. – S. 17-29. - DOI: 10.34984/SCFTP.2023.19.1.002
En
Adaptation of (<i>h,T</i>)-data to calculate some</span> thermodynamic properties of SF<sub>6</sub> on saturation curve. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 1, 17-29 (2024). https://doi.org/10.34984/SCFTP.2023.19.1.002
Key words: supercritical carbon dioxide, molecular dynamics, Raman spectroscopy, Widom delta
An approach to modeling the Raman spectra of supercritical carbon dioxide based on Fourier analysis of the autocorrelation function of the dipole moment calculated by the molecular dynamics method is demonstrated. On its basis, Raman spectra of carbon dioxide were simulated along the 310 K isotherm in the pressure range 0.1–15 MPa. It has been established that in the Widom delta there is a broadening of spectral lines, as well as extrema in the dependences of Raman shifts on pressure. The results obtained are in good agreement with known experimental data and indicate a significant influence of cluster formation on the macroscopic properties of carbon dioxide in the vicinity of the critical point.
doi:10.34984/SCFTP.2024.19.1.003
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ГОСТ
7.0.100-2018
Simulation of raman spectra of supercritical carbon dioxide using the molecular dynamics method / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2024. – Т. 19. – № 1. – С. 30-43. - DOI: 10.34984/SCFTP.2024.19.1.003
TRANSLIT
Modelirovanie Ramanovskih spektrov sverhkriticheskogo dioksida ugleroda metodom molekulyarnoj dinamiki / – Tekst : neposredstvennyj // Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2024. – Т. 19. – № 1. – S. 30-43. - DOI: 10.34984/SCFTP.2024.19.1.003
En
Simulation of raman spectra of supercritical carbon dioxide using the molecular dynamics method. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 1, 30-43 (2024). https://doi.org/10.34984/SCFTP.2024.19.1.003
Key words: avermectin, yield, Streptomyces avermitilis, supercritical fluid extraction, carbon dioxide, rotatable uniform plan, optimization.
The process of supercritical fluid extraction of avermectin from the bacterial biomass of Streptomyces avermitilis with carbon dioxide was optimized by the method of a full factorial experiment using a second-order rotatable uniform plan. When planning, the main levels chosen were a pressure of 25 MPa, a temperature of 60°C, and an extraction duration of 100 min. The analysis of the regression equation made it possible to establish the optimal process parameters: 30 MPa, 85°C, and 133 min. In the control experiment, an extract was obtained with a yield of 13 %, containing 41 % avermectin. The yield of avermectin was 5.36 % of absolutely dry biomass, which exceeds the extraction yields obtained using organic solvents.
doi:10.34984/SCFTP.2024.19.1.004
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ГОСТ
7.0.100-2018
Supercritical fluid extraction of avermectin from <i>Streptomyces avermitilis</i> using carbon dioxide / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2024. – Т. 19. – № 1. – С. 44-55. - DOI: 10.34984/SCFTP.2024.19.1.004
TRANSLIT
Izvlechenie avermektina iz <i>Streptomyces avermitilis</i> sverhkriticheskim dioksidom ugleroda / – Tekst : neposredstvennyj // Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2024. – Т. 19. – № 1. – S. 44-55. - DOI: 10.34984/SCFTP.2024.19.1.004
En
Supercritical fluid extraction of avermectin from <i>Streptomyces avermitilis</i> using carbon dioxide. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 1, 44-55 (2024). https://doi.org/10.34984/SCFTP.2024.19.1.004
Key words: supercritical carbon dioxide, siloxane aerogels, ferrocene
An effective method for the synthesis of hybrid structure siloxane aerogels with ferrocene fragments built into polymer structure has been developed. At the initial stage, a gel was obtained by polycondensation of tetraethoxysilane and ferrocene-containing alkoxysilanes, catalyzed by BF3 · Et2O in acetone. The transformation of gels into aerogels was carried out using SC-CO2. The aerogel samples were characterized in detail by Mossbauer spectroscopy and nitrogen adsorption methods, and the density of the materials was determined. The iron content in the resulting aerogels varies in the range of 3.6—8.7 % by weight of iron (or 11.9—28.7 % by weight of ferrocene units).
doi:10.34984/SCFTP.2024.19.1.005
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ГОСТ
7.0.100-2018
Ferrocene-modified siloxane aerogels / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2024. – Т. 19. – № 1. – С. 56-67. - DOI: 10.34984/SCFTP.2024.19.1.005
TRANSLIT
Modificirovannye ferrocenom siloksanovye aerogeli / – Tekst : neposredstvennyj // Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2024. – Т. 19. – № 1. – S. 56-67. - DOI: 10.34984/SCFTP.2024.19.1.005
En
Ferrocene-modified siloxane aerogels. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 1, 56-67 (2024). https://doi.org/10.34984/SCFTP.2024.19.1.005
Key words: Hypogymnia physodes, supercritical fluid extraction, low molecular weight phenols, flavonoids, atranorine, antibacterial activity
The process of supercritical fluid extraction of the thallus of the lichen species Hypogymnia physodes with carbon dioxide in the presence of acetone as a co-solvent has been studied. An assessment of extraction conditions (temperature, pressure and duration) on the yields of extract, phenolic compounds, including low molecular weight phenols, atranorine and flavonoids was carried out. It has been shown that the main amount of extractives (up to 90 %) is extracted within 40 minutes of extraction. The extract yield reaches 156.5 mg/g, with a content of phenolic compounds up to 87.3 %. The extracts obtained have high antiradical activity (up to 225 rmol Trolox-equiv/g). A positive correlation has been established between the antiradical activity of extracts and the content of phenolic compounds in them, including atranorine. Antibacterial activity of the extracts was revealed against gram-positive (Bacillus subtilis) and gram-negative (Escherichia coli, Proteus mirabilis) strains of microorganisms.
doi:10.34984/SCFTP.2024.19.1.006
Cite
ГОСТ
7.0.100-2018
Supercritical fluid extraction of the lichen thallus <i>Hypogymnia physodes</i> / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2024. – Т. 19. – № 1. – С. 68-82. - DOI: 10.34984/SCFTP.2024.19.1.006
TRANSLIT
Sverhkriticheskaya flyuidnaya ekstrakciya talloma lishajnika <i>Hypogymnia physodes</i> / – Tekst : neposredstvennyj // Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2024. – Т. 19. – № 1. – S. 68-82. - DOI: 10.34984/SCFTP.2024.19.1.006
En
Supercritical fluid extraction of the lichen thallus <i>Hypogymnia physodes</i>. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 1, 68-82 (2024). https://doi.org/10.34984/SCFTP.2024.19.1.006
Key words: carbon nanotubes, rapid expansion of supercritical suspensions, dispersion
The dependence of the degree of CNT deagglomeration on the multiplicity of their treatment by the method of rapid expansion of supercritical suspensions (RESS) under various conditions has been studied. It was shown that double treatment by the RESS method makes it possible to increase the degree of CNT deagglomeration more effectively than a single one. Three-fold treatment in the case of nitrogen leads to a slight increase in the degree of dispersion compared to two-fold. In the case of CO2, three-fold treatment can lead to both an increase and a decrease in the degree of dispersion compared to twofold. When nitrogen is used as a dispersion medium, changes in temperature and pressure do not lead to a change in the degree of dispersion of CNTs. When using CO2, a decrease in fluid density ensures greater efficiency of CNT processing.
doi:10.34984/SCFTP.2023.19.2.002
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ГОСТ
7.0.100-2018
Dispersion of carbon nanotubes using multiple rapid expansion of supercritical suspensions / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2024. – Т. 19. – № 2. – С. 16-26. - DOI: 10.34984/SCFTP.2023.19.2.002
TRANSLIT
Dispergirovanie uglerodnyh nanotrubok metodom mnogokratnogo bystrogo rasshireniya sverhkriticheskih suspenzij / – Tekst : neposredstvennyj // Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2024. – Т. 19. – № 2. – S. 16-26. - DOI: 10.34984/SCFTP.2023.19.2.002
En
Dispersion of carbon nanotubes using multiple rapid expansion of supercritical suspensions. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 2, 16-26 (2024). https://doi.org/10.34984/SCFTP.2023.19.2.002
Key words: supercritical carbon dioxide, betulin, solubility, co-solvent, equation of state
The results of experimental investigation of betulin solubility in pure and modified supercritical carbon dioxide in the range of temperature (313.15 -333.15 K) and pressure (8.00-30.00 MPa) using the dynamic method are presented. It was found that in pure supercritical carbon dioxide betulin does not dissolve but only swells. The addition of 5 %
ethanol as a co-solvent increases the solubility. The pressures corresponding to the first
and second crossover points of - (7.7-8.3) MPa and -(27.1-27.6) MPa, respectively,
are established in this work. The results of the descri ption of the experimental data using
a model based on the Peng-Robinson equation of state are presented.
doi:10.34984/SCFTP.2023.19.2.001
Cite
ГОСТ
7.0.100-2018
Solubility of betulin in supercritical CO<sub>2</sub><br> and CO<sub>2</sub> + ethanol mixture / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2024. – Т. 19. – № 2. – С. 6-15. - DOI: 10.34984/SCFTP.2023.19.2.001
TRANSLIT
Rastvorimost' betulina v sverhkriticheskom CO<sub>2</sub> i v smesi CO<sub>2</sub> + etanol / – Tekst : neposredstvennyj // Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2024. – Т. 19. – № 2. – S. 6-15. - DOI: 10.34984/SCFTP.2023.19.2.001
En
Solubility of betulin in supercritical CO<sub>2</sub><br> and CO<sub>2</sub> + ethanol mixture. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 2, 6-15 (2024). https://doi.org/10.34984/SCFTP.2023.19.2.001
Key words: adsorption, palladium hexafluoroacetylacetonate, hypercrosslinked polystyrene, aluminum oxide, supercritical fluid
The paper discusses the adsorption of palladium hexafluoroacetylacetonate (Pd(hfa)2) onto porous carriers (γ-Al2O3 and hypercrosslinked polystyrene) in supercritical CO2 to obtain supported palladium catalysts. The transition conditions of the Pd(hfa 2/CO2 system into the single-phase region have been studied. It is shown that due to the sufficiently high solubility of the palladium precursor in CO2, its deposition can be carried out at relatively low pressures in the system (- 8,5 MPa). The adsorption of Pd(hfa)2 on chosen carriers can be well characterized by the Langmuir equation. The system pressure increase under isothermal conditions negatively affects the amount of adsorbed precursor, due to the competitive CO2 adsorption and the distribution shift in the system. The system temperature increase under isochoric conditions leads to an increase in the adsorption limit.
doi:10.34984/SCFTP.2023.19.2.003
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ГОСТ
7.0.100-2018
Deposition of palladium hexafluoroacetylacetonate on porous matrices by adsorption in a supercritical CO<sub>2</sub> / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2024. – Т. 19. – № 2. – С. 27-43. - DOI: 10.34984/SCFTP.2023.19.2.003
TRANSLIT
Adsorbcionnoe nanesenie geksaftoracetilacetonata palladiya na poristye matricy v srede sverhkriticheskogo CO<sub>2</sub> / – Tekst : neposredstvennyj // Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2024. – Т. 19. – № 2. – S. 27-43. - DOI: 10.34984/SCFTP.2023.19.2.003
En
Deposition of palladium hexafluoroacetylacetonate on porous matrices by adsorption in a supercritical CO<sub>2</sub>. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 2, 27-43 (2024). https://doi.org/10.34984/SCFTP.2023.19.2.003
Key words: aerogel, germanium oxide, praseodymium, soakage, impregnation, luminescence
An easy-to-implement technique for obtaining REE-doped GeO2 aerogels is proposed. Optimal synthesis conditions have been determined to achieve a uniform distribution of the ion-dopant in the matrix. The effect of praseodymium on the luminescent characteristics of GeO2 aerogels when excited by radiation with wavelengths of 240, 255 and 390 nm has been established.
doi:10.34984/SCFTP.2023.19.2.004
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ГОСТ
7.0.100-2018
Synthesis of pr-doped GeO<sub>2</sub> aerogels by impregnation method / – Текст : // Сверхкритические Флюиды: Теория и Практика.. – 2024. – Т. 19. – № 2. – С. 44-58. - DOI: 10.34984/SCFTP.2023.19.2.004
TRANSLIT
Sintez GeO<sub>2</sub>-aerogelej, legirovannyh prazeodimom, metodom propitki / – Tekst : // Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2024. – Т. 19. – № 2. – S. 44-58. - DOI: 10.34984/SCFTP.2023.19.2.004
En
Synthesis of pr-doped GeO<sub>2</sub> aerogels by impregnation method. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 2, 44-58 (2024). https://doi.org/10.34984/SCFTP.2023.19.2.004
Key words: critical phenomena, paired correlation function, scale transformations, scale invariance, optical diagnostics of the critical state of fluids
In this paper we have solved the «fluctuation theorem» on the mesoscopic length scale for the first time in a direct way. An analytical expression for the pair correlation function of the critical state of fluid was obtained, where the density variance is the parameter that could be easily defined by optical measurements. By comparison of our result with the Ornstein—Zernike pair correlation function we have got the Fisher index η= 0.25 to increase the convergence. It was shown that the obtained results provide a reliable theoretical basis for optical diagnostics of the critical state of fluids.
doi:10.34984/SCFTP.2023.19.2.005
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ГОСТ
7.0.100-2018
Pair correlation function for equilibrium critical state of fluids on the mesoscopic space scale / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2024. – Т. 19. – № 2. – С. 59-81. - DOI: 10.34984/SCFTP.2023.19.2.005
TRANSLIT
Parnaya korrelyacionnaya funkciya ravnovesnogo kriticheskogo sostoyaniya flyuidov v mezoskopicheskom masshtabe dlin / – Tekst : neposredstvennyj // Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2024. – Т. 19. – № 2. – S. 59-81. - DOI: 10.34984/SCFTP.2023.19.2.005
En
Pair correlation function for equilibrium critical state of fluids on the mesoscopic space scale. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 2, 59-81 (2024). https://doi.org/10.34984/SCFTP.2023.19.2.005
Key words: hydrolysis lignin, depolymerization, n-hexane, supercritical conditions, hydrogenation, Ru/C
Depolymerization of hydrolysis lignin in supercritical n-hexane medium was carried out in two stages: 1) lignin treatment in an autoclave at 250°C and 15 MPa; 2) hydrogenation of the solution obtained in the first stage at 250°C and 9 MPa on a Ru/C catalyst. The products of the first and second stages were analyzed by HPLC, GPC, gas chromatography, chromatography-mass spectrometry, and elemental analysis. At the first stage, the degree of depolymerization was 17 %, the mono- and oligomeric fragments of lignin that passed into solution as a result of depolymerization have an MMD from 65 Da to 270 kDa. Monomer composition of the solution: mono-, di-, tri- and tetraalkyl derivatives of benzene (2.8 wt. %), guaiacol and its alkyl derivatives (0.6 wt. %), including coniferyl alcohol (0.06 wt. %). At the second stage of transformation the following processes occur: 1) depolymerization of oligomers to monomers; 2) hydrogenation of monomeric phenols to derivatives of cyclohexane and its oxo derivatives; 3) formation of gas products, mainly methane (95 vol. %), as a result of hydrocracking of the solvent.
doi:10.34984/SCFTP.2023.19.2.006
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ГОСТ
7.0.100-2018
Two-stage thermal and heterogeneous catalytic transformation of hydrolysis lignin in supercritical <i>n</i>-hexane / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2024. – Т. 19. – № 2. – С. 82-94. - DOI: 10.34984/SCFTP.2023.19.2.006
TRANSLIT
/ – Tekst : neposredstvennyj // Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2024. – Т. 19. – № 2. – S. 82-94. - DOI: 10.34984/SCFTP.2023.19.2.006
En
Two-stage thermal and heterogeneous catalytic transformation of hydrolysis lignin in supercritical <i>n</i>-hexane. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 2, 82-94 (2024). https://doi.org/10.34984/SCFTP.2023.19.2.006
Key words: supercritical fluid, solubility, prediction, machine learning
A review of researches devoted to the application of machine learning methods and neural network technologies in the prediction of solubility of various substances in supercritical (SC) fluids. Using a simple neural network of three layers a prototype of a solubility prediction system was developed based on the example of an existing data set on the solubility of aromatic hydrocarbons in SC carbon dioxide. Its efficiency has been shown and further directions of research in this field have been identified.
doi:10.34984/SCFTP.2024.19.3.001
Cite
ГОСТ
7.0.100-2018
Сapabilities of machine learning methods in prediction of solubility of substances in supercritical carbon dioxide / – Текст : // Сверхкритические Флюиды: Теория и Практика.. – 2024. – Т. 19. – № 3. – С. 4-12. - DOI: 10.34984/SCFTP.2024.19.3.001
TRANSLIT
Vozmozhnosti metodov mashinnogo obucheniya v zadachah prognozirovaniya rastvorimosti veshchestv v sverhkriticheskom diokside ugleroda / – Tekst : // Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2024. – Т. 19. – № 3. – S. 4-12. - DOI: 10.34984/SCFTP.2024.19.3.001
En
Сapabilities of machine learning methods in prediction of solubility of substances in supercritical carbon dioxide. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 3, 4-12 (2024). https://doi.org/10.34984/SCFTP.2024.19.3.001
Key words: chitosan, alginate, magnetite, aerogel, supercritical fluid technologies.
Composite aerogels were obtained based on two-component sodium alginate—chitosan hydrogels with the inclusion of magnetite and subsequent drying in supercritical carbon dioxide. The optimal concentration of magnetite introduced into the sodium alginate— chitosan system and the mode of supercritical drying of composite hydrogels in the carbon dioxide were experimentally established, making it possible to obtain the aerogel with a maximally developed porous structure. Using the method of low-temperature nitrogen adsorption, it was shown that the resulting aerogels are characterized by a developed mesoporous structure with open cylindrical pores, the maximum specific surface is 300 m2/g. Experimental studies have shown that the developed composite magnetite-containing aerogels have high bactericidal activity against S. aureus, E. coli and B. subtilis, due to which they have great potential for creating various medical products based on them, including wound dressings, carriers active medicinal substances, hemostatic or sorption materials.
doi:10.34984/SCFTP.2024.19.3.002
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ГОСТ
7.0.100-2018
Preparation magnetite-containing composite aerogels based on alginate-chitosan complex / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2024. – Т. 19. – № 3. – С. 13-29. - DOI: 10.34984/SCFTP.2024.19.3.002
TRANSLIT
Poluchenie magnetitsoderzhashchih kompozitnyh aerogelej na osnove kompleksa al'ginat- hitozan / – Tekst : neposredstvennyj // Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2024. – Т. 19. – № 3. – S. 13-29. - DOI: 10.34984/SCFTP.2024.19.3.002
En
Preparation magnetite-containing composite aerogels based on alginate-chitosan complex. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 3, 13-29 (2024). https://doi.org/10.34984/SCFTP.2024.19.3.002
Key words: aerogels, gC3N4, sulfides, photocatalysis, oxidation
Composites of gC3N4 particles immobilized in monolithic silica aerogel have been obtained and their physicochemical photocatalytic properties have been studied. Their manifold recyclability and higher, compared to the gC3N4 in its free form, photocatalytic activity in reactions of alkyl aryl sulfides oxidation by molecular oxygen in SC-CO2 medium have been shown. The results presented in this work can serve as a basis for the development of sustainable and efficient processes of organic compounds oxidation.
doi:10.34984/SCFTP.2024.19.3.003
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ГОСТ
7.0.100-2018
Composites of graphitic carbon nitride with silica aerogel – recyclable immobilized photocatalysts for sulfides oxidation by oxygen in SC-CO<sub>2</sub> / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2024. – Т. 19. – № 3. – С. 30-46. - DOI: 10.34984/SCFTP.2024.19.3.003
TRANSLIT
Kompozity grafitopodobnogo nitrida ugleroda s silikatnym aerogelem – recikliziruemye immobilizovannye fotokatalizatory reakcii okisleniya sulfidov kislorodom v srede SC-CO<sub>2</sub> / – Tekst : neposredstvennyj // Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2024. – Т. 19. – № 3. – S. 30-46. - DOI: 10.34984/SCFTP.2024.19.3.003
En
Composites of graphitic carbon nitride with silica aerogel – recyclable immobilized photocatalysts for sulfides oxidation by oxygen in SC-CO<sub>2</sub>. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 3, 30-46 (2024). https://doi.org/10.34984/SCFTP.2024.19.3.003
Key words: polylactide, foaming, supercritical carbon dioxide, laser radiation, dynamic scattering, mobility of interphase boundaries
Multiple scattering of laser radiation on the structure of forming porous matrices results in spatiotemporal fluctuations of intensity in the scattered radiation field (dynamic speckle modulation). Using the effect of dynamic scattering of laser radiation in the volume of evolving foams, the process of formation of highly porous polylactide matrices during their synthesis by the supercritical (SC) fluid foaming method in a carbon dioxide medium is analyzed. The average lifetime of dynamic speckles, τlt, which are recorded using a high-speed CMOS camera, is considered as a parameter carrying information on the ensemble-averaged mobility of scattering centers (boundaries of developing pores). A phenomenological model has been developed that establishes the relationship between the current values of τlt, macroscopic parameters of the foam (volume and rate of its change) and the ensemble-averaged microscopic mobility of interphase boundaries (the first derivative of the average pore size over time). The experimental data interpretation using the developed model on the dynamics of polylactide foam expansion during rapid (0.03 MPa/s) and slow (0.006 MPa/s) pressure release of SC-CO2 in the reactor are presented. It is established that in the case of rapid pressure release, structural
rearrangements in the foam volume continue even after it reaches the maximum value of
the expansion factor. A qualitative interpretation of this feature is given based on the
concepts of thermodynamic nonequilibrium of porous matrices during their formation.
doi:10.34984/SCFTP.2024.19.3.004
Cite
ГОСТ
7.0.100-2018
Dynamic scattering of laser radiation by polylactide foams in the course of their synthesis using the supercritical fluid foaming method: analysis of the interphase boundary mobility / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2024. – Т. 19. – № 3. – С. 47-65. - DOI: 10.34984/SCFTP.2024.19.3.004
TRANSLIT
Dinamicheskoe rasseyanie lazernogo izlucheniya polilaktidnymi penami v processe sinteza metodom sverkriticheskogo flyuidnogo vspenivaniya: analiz podvizhnosti mezhfaznyh granic / – Tekst : neposredstvennyj // Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2024. – Т. 19. – № 3. – S. 47-65. - DOI: 10.34984/SCFTP.2024.19.3.004
En
Dynamic scattering of laser radiation by polylactide foams in the course of their synthesis using the supercritical fluid foaming method: analysis of the interphase boundary mobility. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 3, 47-65 (2024). https://doi.org/10.34984/SCFTP.2024.19.3.004
Key words: mixed oxides, synthesis, water fluid, lanthanum, group IIA elements, aluminates, catalytic oxidation, oxidative coupling of methane
The formation of mixed oxides in La2O3/MO—Al2O3 systems (M is a group IIA element: Mg, Ca, Sr or Ba) during high-temperature treatment and treatment with water fluids (WF) has been studied. It has been shown that high-temperature treatment of the corresponding group IIA metal aluminate with supported lanthanum nitrate leads to the formation of LaAlO3 only in the case of the Mg-containing system. In other cases, there is no transformation of the initial aluminates, and lanthanum oxide is formed. When treating La/M—Al ternary systems with WF, the formation of LaAlO3 is observed in all cases. Also, in all samples, except for Ba-containing, phases of free metal oxides of group IIA elements appear. The increase in activity and selectivity in the OCM process in La/M—Al ternary oxide systems compared to double M—Al systems is associated with the presence of a separate La2O3 oxide phase.
doi:10.34984/SCFTP.2024.19.3.005
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ГОСТ
7.0.100-2018
Formation of compounds and phases in oxide systems La-M-Al (M – Ca, Mg, Sr, Ba) during treatment with water fluid and their catalytic properties in oxidative coupling of methane / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2024. – Т. 19. – № 3. – С. 66-78. - DOI: 10.34984/SCFTP.2024.19.3.005
TRANSLIT
Sistemah La-M-Al (M – Ca, Mg, Sr, Ba) pri obrabotke vodnym flyuidom i ih kataliticheskie svojstva v processe okislitelnoj kondensacii metana / – Tekst : neposredstvennyj // Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2024. – Т. 19. – № 3. – S. 66-78. - DOI: 10.34984/SCFTP.2024.19.3.005
En
Formation of compounds and phases in oxide systems La-M-Al (M – Ca, Mg, Sr, Ba) during treatment with water fluid and their catalytic properties in oxidative coupling of methane. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 3, 66-78 (2024). https://doi.org/10.34984/SCFTP.2024.19.3.005
Key words: subcritical water, agro-industrial complex wastes, buckwheat husk, polyphenols, anti-acetylcholinesterase activity
The effect of the extraction method and conditions on polyphenol composition of buckwheat (Fagopyrum esculentum) husk extracts and their acetylcholinesterase (AChE) inhibition activity was studied. The extracts were obtained both by the traditional method of water-ethanol extraction and in a subcritical water (SBW) medium at 120—220 °C. A direct correlation was found between anticholinesterase activity and the content of polyphenols in the extracts. The highest activity in inhibiting AChE was demonstrated by the extract obtained in the SBW medium at 220 °C, which contains the maximum amounts of the sum of polyphenols and flavonoids. This indicates the decisive role of these compounds in AChE inhibition. The obtained data allow us to consider such extracts as inexpensive and renewable sources of polyphenolic compounds and flavonoids with P-vitamin and neuroprotective activity.
doi:10.34984/SCFTP.2024.19.3.006
Cite
ГОСТ
7.0.100-2018
Effect of extraction method and conditions on the polyphenol content in buckwheat husk (<i>Fagopyrum esculentum</i>) extracts and their activity in acetylcholinesterase inhibition / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2024. – Т. 19. – № 3. – С. 79-92. - DOI: 10.34984/SCFTP.2024.19.3.006
TRANSLIT
Vliyanie metoda i uslovij ekstrakcii na soderzhanie polifenolov v ekstraktah luzgi grechihi (<i>Fagopyrum esculentum</i>) i ih aktivnost v ingibirovanii acetilholinesterazy / – Tekst : neposredstvennyj // Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2024. – Т. 19. – № 3. – S. 79-92. - DOI: 10.34984/SCFTP.2024.19.3.006
En
Effect of extraction method and conditions on the polyphenol content in buckwheat husk (<i>Fagopyrum esculentum</i>) extracts and their activity in acetylcholinesterase inhibition. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 3, 79-92 (2024). https://doi.org/10.34984/SCFTP.2024.19.3.006
Key words: carbon dioxide, N-isopropylacrilamide, solubility, solubility isotherms, phase equilibrium, Chrastil’s model.
Solubility isotherms of N-isopropylacrylamide (NIPAM), obtained via visual synthetic method at temperatures 304.8—353.0 K and pressures 0.1—40.0 MPa, are reported in the current paper. The maximal solubility of NIPAM within this range of parameters is determined as well. The crossover region in regards to the P mix = ƒ (x, mol. %) isotherms is located and the nature of the phenomenon is discussed further. Predictive ability of the Chrastil’s model is evaluated in relation to the NIPAM-CO2 system.
doi:10.34984/SCFTP.2024.19.3.007
Cite
ГОСТ
7.0.100-2018
Solubility of N-isopropylacrylamide in carbon dioxide / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2024. – Т. 19. – № 3. – С. 93-106. - DOI: 10.34984/SCFTP.2024.19.3.007
TRANSLIT
Rastvorimost N-izopropilakrilamida v diokside ugleroda / – Tekst : neposredstvennyj // Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2024. – Т. 19. – № 3. – S. 93-106. - DOI: 10.34984/SCFTP.2024.19.3.007
En
Solubility of n-isopropylacrylamide in carbon dioxide. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 3, 93-106 (2024). https://doi.org/10.34984/SCFTP.2024.19.3.007
Application of Supercritical Fluids for Separation of Group Components of Petroleum Systems (Review)
Key words: supercritical fluids, group composition, asphaltenes, supercritical fluid extraction, carbon dioxide, anti-solvent, fractionation
The review article examines information on modern methods of separating oils and oil residues in the analysis of group composition using supercritical fluids. The features of the influence of the composition and properties of individual group components of oil samples on further processing has been shown. Traditional methods of separating petroleum feedstock into group components has been briefly reviewed. The results of modern studies of extraction methods for separating oil samples using supercritical fluids has been shown. Information is presented on new methods for the extraction of asphaltenes and fractionation of heavy oils and oil residues using СО2.
doi:10.34984/SCFTP.2024.19.4.001
Cite
ГОСТ
7.0.100-2018
Application of Supercritical Fluids for Separation of Group Components of Petroleum Systems (Review) / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2024. – Т. 19. – № 4. – С. 3-24. - DOI: 10.34984/SCFTP.2024.19.4.001
TRANSLIT
Primenenie sverhkriticheskih flyuidov dlia razdeleniia gruppovyh komponentov neftianyh sistem / – Tekst : neposredstvennyj // Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2024. – Т. 19. – № 4. – S. 3-24. - DOI: 10.34984/SCFTP.2024.19.4.001
En
Application of Supercritical Fluids for Separation of Group Components of Petroleum Systems (Review). Sverhkriticheskie Flyuidy: Teoriya i Praktika, 4, 3-24 (2024). https://doi.org/10.34984/SCFTP.2024.19.4.001