Key words: carbamide, ammonia, water-oxygen fluid, oxidation, hydrolysis
The transformations of carbamide in a water-oxygen fluid (at a carbamide concentration of 0.29—0.39 mol/l, oxygen excess coefficient OR = 0.98—1.25, mole fraction of water 70.0—91.3 %) was studied in a reactor periodic type when heated to 873 K at a rate of 1 K/min. It has been shown that the transformations proceed via the mechanism of parallel and sequential reactions, including carbamide hydrolysis, formation and decomposition of cyanuric acid, oxidation of ammonia and products of cyanuric acid decomposition. From the analysis of the time dependences of temperature and pressure, it follows that the oxidation of carbamide occurs predominantly heterogeneously on the surfaces of the reactor wall and the Pt—Rh/Pt-thermocouple inserted into the center of the reaction volume. It has been established that excess oxygen (OR = 1.25) or the addition of NaOH leads to an increase in the fraction of nitrogen converted into N2 and prevents the formation of cyanuric acid. The influence of the concentration of reagents on the ratio of carbamide conversion pathways and the dynamics of heat release is discussed.
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ГОСТ
7.0.100-2018
Peculiarities of carbamide hydrolysis and oxidation in water-oxygen fluid / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2023. – Т. 18. – № 4. – С. 85-96. - DOI: 10.34984/SCFTP.2023.18.4.003
TRANSLIT
Osobennosti gidroliza i okisleniya karbamida v vodokislorodnom flyuide / – Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2023. – Т. 18. – № 4. – S. 85-96. - DOI: 10.34984/SCFTP.2023.18.4.003
En
. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 4, 85-96 (2023). https://doi.org/10.34984/SCFTP.2023.18.4.003
Key words: isopropanol, water, oxides, dehydration, dehydrogenation, reduction.
Transformations of a series of simple oxides (Al2O3, SiO2, La2O3, CeO2, PrO2) during their treatment in an autoclave with isopropanol (i-C3H7OH) under supercritical (SC) conditions and subcritical water vapor were studied. It has been shown that at 350 °C in the presence of water vapor, a more intense decrease of specific surface areas and the transition of some of them (oxides of aluminum, lanthanum and praseodymium) into hydroxides occur. Under the influence of i C3H7OH for 6 hours at 350 °C almost complete conversion of PrO2 occurs, accompanied by its reduction and partial transition to hydroxide. In the case of CeO2, no transformations in both media (i C3H7OH, water vapor), including a decrease in specific surface area, hydration and reduction, were observed. The differences in the behavior of CeO2 and PrO2 are explained by the difference in the values of the 4th ionization potential of the Ce and Pr atoms and, as a consequence, in the binding energies of oxygen in higher oxides. The formation of products of various reactions of i-C3H7OH was detected, the composition of which depends on the type of oxide being processed. The most intense transformation of i-C3H7OH occurs in the presence of Al2O3; in this case, dehydration products (propylene, diisopropyl ether) are formed predominantly. In the presence of La, Ce and Pr oxides, the dehydrogenation process is more intense with the formation of acetone and hydrogen (maximum in the presence of La2O3). The catalytic nature of the isopropanol decomposition in the presence of the studied simple oxides has been established. SiO2, which does not have pronoun- ced acid-base and redox properties, exhibits the least activity in the decomposition of i- C3H7OH. It has been suggested that when oxides are treated with SC isopropanol, their structuring occurs under the action of water vapor, which is a product of the transformation of i-C3H7OH. The catalytic activity of the autoclave material (stainless steel) in the decomposition of i C3H7OH along both routes — dehydration and dehydrogenation — was noted.
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7.0.100-2018
Transformations of simple oxides and reactions of isopropanol during their interaction under supercritical conditions / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2023. – Т. 18. – № 4. – С. 68-84. - DOI: 10.34984/SCFTP.2023.18.4.002
TRANSLIT
Vzaimodejstvie prostyh oksidov s izopropanolom pri temperature vyshe kriticheskoj / – Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2023. – Т. 18. – № 4. – S. 68-84. - DOI: 10.34984/SCFTP.2023.18.4.002
En
Transformations of simple oxides and reactions of isopropanol during their interaction under supercritical conditions. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 4, 68-84 (2023). https://doi.org/10.34984/SCFTP.2023.18.4.002
Key words: critical point, crossover theory, supercritical fluids, scaling, equation of state, Widom lines
This review provides a detailed description of the main provisions of the modern non-classical theory of critical phenomena in pure fluids, based on the hypothesis of scale invariance (scaling). The main types (parametric and six-term or renormalized Landau expansion), theoretically based, crossover equations of state (EoS) of pure fluids and their application to describe the anomalous behavior of thermodynamic properties near and supercritical fluids are described in detail. It is shown that the crossover model of EoS covers all the characteristic features of the scaling behavior of the thermodynamic properties of pure fluids in the asymptotic region of the critical point (CP) in the form of simple power laws with universal critical exponents and transforms into the classical EoS (in particular, the Landau expansion) far from the critical (fluctuation) region. A detailed comparison of the predictions of the crossover model of EoS with experimental data on thermodynamic properties for a wide class of supercritical fluids in a wide range of temperatures and pressures is presented. Crossover EoS of pure fluids were used to quantify the boundary of the region ofinfluence of critical fluctuations on thermodynamic properties, i.e., to estimate the contribution of the fluctuation component to the experimentally observed anomalous of the thermodynamic properties of supercritical fluids. An interpretation of supercritical phase transitions (Widom lines) is given on the basis of the concept of large-scale critical fluctuations and the crossover theory. The review also considers dynamic crossover phenomena to describe the effect of fluctuations on the critical increase in transport properties (thermal conductivity, conductivity temperature, and viscosity) near and in supercritical fluids.
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ГОСТ
7.0.100-2018
Influence of critical fluctuations on the thermodynamic and transport properties of supercritical fluids. Non-classical crossover equations of state / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2023. – Т. 18. – № 4. – С. 3-67. - DOI: 10.34984/SCFTP.2023.18.4.001
TRANSLIT
Vliyanie kriticheskih fluktuacij na termodinamicheskie i transportnye svojstva sverhkriticheskih flyuidov. neklassicheskie krossovernye uravneniya sostoyaniya / – Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2023. – Т. 18. – № 4. – S. 3-67. - DOI: 10.34984/SCFTP.2023.18.4.001
En
. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 4, 3-67 (2023). https://doi.org/10.34984/SCFTP.2023.18.4.001
Key words: extraction, neodymium, carbon dioxide, TODGA, nitric acid, phase equilibrium
Some equilibria in the system Nd3+ —water—nitric acid—TODGA—CO2 (TODGA — N,N,N′,N′-tetraoctyl diglycolamide) and the efficiency of extraction of Nd3+ ions from aqueous solutions into the supercritical (SC) CO2-based phase at 313—353 K and 180—400 bar were studied. It has been shown that in the absence of TODGA, the transfer of Nd3 ions to the SC-phase does not occur. The extraction efficiency increases with decreasing temperature and with increasing concentration of nitric acid (CNA) in the aqueous solution. At 313 K, CNA ≥ 1.5 mol/l, TODGA content not less than 100 mol/g-at. Nd and CO2 pressure ensuring complete dissolution of TODGA (>19 MPa), a complete transfer of Nd3+ to the SC-phase is observed. As the content of neodymium ions in the system increases, the pressure and amount of CO2 required for complete dissolution of TODGA increases too. This is apparently due to a decrease in the intensity of intermolecular interactions in the SC-phase at increasing concentration in it of large and polar Nd complexes with TODGA and nitrate ions
doi:10.34984/SCFTP.2023.18.3.006
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ГОСТ
7.0.100-2018
Phase equilibria in the system nd3+–water–nitric acid—TODGA–CO2 and the efficiency of supercritical fluid extraction of neodymium ions / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2023. – Т. 18. – № 3. – С. 69-83. - DOI: 10.34984/SCFTP.2023.18.3.006
TRANSLIT
Fazovye ravnovesiya v sisteme Nd3+—voda—azotnaya kislota—TODGA—SO2 i effektivnost' sverhkriticheskoj flyuidnoj ekstrakcii ionov neodima / – Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2023. – Т. 18. – № 3. – S. 69-83. - DOI: 10.34984/SCFTP.2023.18.3.006
En
Phase equilibria in the system nd3+–water–nitric acid—TODGA–CO2 and the efficiency of supercritical fluid extraction of neodymium ions. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 3, 69-83 (2023). https://doi.org/10.34984/SCFTP.2023.18.3.006
Key words: mixed La—Al-oxides, lanthanum aluminate, lanthanum oxide, structure, water fluid, catalysts, stability, oxidative coupling of methane
The catalytic properties in the oxidative coupling of methane (OCM) and the structural features of a series of mixed lanthanum-aluminum oxides with a constant atomic ratio La : Al = 1 : 1 were studied. The samples were prepared from precursors containing La and Al nitrates and organic component — filter paper or starch. After drying and burning the organic component, the samples were subjected to additional heat treatment and exposure to water fluid (WF) with a density of 0.2 g cm-3 at 415 °C. After calcination at 900°C, all the samples contain a phase of lanthanum aluminate LaAlO3 with a cubic perovskite structure. Varying the type of organic component, as well as the sequence of procedures and processing conditions leads to the production of samples with different morphologies and catalytic properties. The minimum activity, selectivity for OCM products and stability over time is demonstrated by the sample obtained under conditions conducive to the formation of the most ordered structure — successively calcined at 900 °C, treated in a WF medium and re-calcined at 900 °C. The most efficient and stable turned out to be the sample whose crystal structure was formed mainly in the WF medium. It was noted that there is no correlation between the morphology of particles and the specific surface area of the samples, on the one hand, and their catalytic properties, on the other. It was assumed that the catalytic properties are determined by the type and number of point defects in the crystal structure — primarily cation vacancies and, as a consequence, hole centers of the [O–] type in the anion sublattice.
doi:10.34984/SCFTP.2023.18.3.005
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ГОСТ
7.0.100-2018
Structural features of mixed La—Al-oxides and stability of their catalytic properties in oxidative coupling of methane / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2023. – Т. 18. – № 3. – С. 51-68. - DOI: 10.34984/SCFTP.2023.18.3.005
TRANSLIT
Strukturnye osobennosti smeshennyh La-Al-oksidov i stabil'nost ih kataliticheskih svojstv v processe okislitelnoj kondensacii metana / – Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2023. – Т. 18. – № 3. – S. 51-68. - DOI: 10.34984/SCFTP.2023.18.3.005
En
Structural features of mixed La—Al-oxides and stability of their catalytic properties in oxidative coupling of methane. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 3, 51-68 (2023). https://doi.org/10.34984/SCFTP.2023.18.3.005
Key words: supercritical antisolvent precipitation, morphology, crystallization, phase equilibria
The effect of pressure on the size and morphology of levofloxacin hydrochloride particles precipitated by supercritical antisolvent precipitation (SAS) was investigated. It is shown that the crystallization of levofloxacin from the two-phase CO2—dimethylforamide—levofloxacin hydrochloride system leads to the production of particles with a bimodal size distribution. Crystallization from a single-phase system leads to a change in the mixing mode of CO2 and solution, and as a result, preci pitation of particles with a monomodal size distribution is observed. Liquid—gas equilibrium curves were obtained for the CO2— dimethylforamide—levofloxacin hydrochloride system at a temperature of 40°C.
doi:10.34984/SCFTP.2023.18.3.004
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7.0.100-2018
Supercritical antisolvent precipitation of levofloxacin hydrochloride from single-phase and two-phase mixtures of CO2—dimethylformamide / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2023. – Т. 18. – № 3. – С. 39-50. - DOI: 10.34984/SCFTP.2023.18.3.004
TRANSLIT
Sverhkriticheskoe antisolventnoe osazhdenie gidrohlorida levofloksacina iz odnofaznoj i dvuhfaznoj smesej SO2—dimetilformamid / – Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2023. – Т. 18. – № 3. – S. 39-50. - DOI: 10.34984/SCFTP.2023.18.3.004
En
Supercritical antisolvent precipitation of levofloxacin hydrochloride from single-phase and two-phase mixtures of CO2—dimethylformamide. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 3, 39-50 (2023). https://doi.org/10.34984/SCFTP.2023.18.3.004
Key words: laminariya japanese Saccharina japonica, iodine, alginic acid, subcritical water, extraction, functional nutrition.
Within the framework of this work, the efficiency of extracting iodine and alginic acids from dry thalli of laminariya japanese (Saccharina japonica) with subcritical water at temperatures of 130, 150 and 170 °C in the dynamic extraction mode was evaluated. It has been established that during extraction, iodine is completely extracted from the thallus of laminariya japanese, however, in the dynamic extraction mode, only about 45 % of iodine-containing compounds pass into the extract, the rest remains in the mucus that forms around the particles of laminariya during the extraction process. The obtained extracts of laminariya japanese contain fatty and phenolic acids, alcohols, carbohydrates. Marmalade, made on the basis of a subcritical water extract of kelp weighing about 6 g, contains about 20 daily doses of iodine, can be used as a functional food product.
doi:10.34984/SCFTP.2023.18.3.003
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ГОСТ
7.0.100-2018
Subcritical water extracts of laminariya japanese as a potential basis for functional nutrition / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2023. – Т. 18. – № 3. – С. 29-38. - DOI: 10.34984/SCFTP.2023.18.3.003
TRANSLIT
Subkriticheskie vodnye ekstrakty laminarii yaponskoj kak potencialnaya osnova funkcional'nogo pitaniya / – Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2023. – Т. 18. – № 3. – S. 29-38. - DOI: 10.34984/SCFTP.2023.18.3.003
En
Subcritical water extracts of laminariya japanese as a potential basis for functional nutrition. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 3, 29-38 (2023). https://doi.org/10.34984/SCFTP.2023.18.3.003
Key words: svinec, okislenie, vodokislorodnyj flyuid, peroksid vodoroda
The paper presents the research results of the oxidation of bulk lead samples with oxygen, water vapor, water-oxygen mixture, and hydrogen peroxide solution during heating of the reactor at a rate of 1 K/min up to 873 K under the conditions of high reactant density (ρН2О ≤ 4,58 и ρO2 ≤ 0,58 моль/дм3). The smallest gain in the weight of the samples was detected during the oxidation of lead with water vapor and oxygen, and the largest one, with the H2O/O2 mixture. It follows from the time dependences of the temperature and pressure of the reaction mixture that oxidation of lead by the H2O/O2 mixture noticeably accelerates at T > 425 K. An increase in the O2 content in the mixture and a decrease in the water vapor density intensify the oxidation. According to the X-ray diffraction analysis data, Pb3O4 (minium) predominates in the composition of lead oxidation products formed in the H2O/O2 mixture. It has been revealed that the size and morphology of oxidized lead particles depend on the composition of the reaction mixture. The mechanisms of lead oxidation are discussed.
doi:10.34984/SCFTP.2023.18.3.002
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ГОСТ
7.0.100-2018
Peculiarities of bulk lead sample oxidation in water-oxygen fluid / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2023. – Т. 18. – № 3. – С. 15-28. - DOI: 10.34984/SCFTP.2023.18.3.002
TRANSLIT
Osobennosti okisleniya massivnyh obrazcov svinca v vodokislorodnom flyuide / – Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2023. – Т. 18. – № 3. – S. 15-28. - DOI: 10.34984/SCFTP.2023.18.3.002
En
Peculiarities of bulk lead sample oxidation in water-oxygen fluid. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 3, 15-28 (2023). https://doi.org/10.34984/SCFTP.2023.18.3.002
Key words: supercritical extraction, wild carrots, HCMS, ecology, sterols, fatty acids
To study the influence of ecological growing conditions on the chemical composition of plants, supercritical carbon dioxide extraction of wild carrot samples, widespread in all regions of the world with a temperate climate (Daucus carota subsp. maritimus). Using the methods of gas-liquid chromatography and mass spectral analysis, volatile organic compounds, fatty acids and phytosterols in the studied objects were determined in the extracts obtained. The dependence of the chemical composition of wild carrots on its growing conditions (temperature, precipitation, solar radiation, etc.) is shown.
doi:10.34984/SCFTP.2023.18.3.001
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ГОСТ
7.0.100-2018
Relationship of component composition of supercritical СО2 extracts of wild carrots with growing conditions / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2023. – Т. 18. – № 3. – С. 3-14. - DOI: 10.34984/SCFTP.2023.18.3.001
TRANSLIT
Zavisimost komponentnogo sostava sverhkriticheskogo SO2-ekstrakta morkovi dikoj ot uslovij proizrastaniya / – Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2023. – Т. 18. – № 3. – S. 3-14. - DOI: 10.34984/SCFTP.2023.18.3.001
En
Relationship of component composition of supercritical СО2 extracts of wild carrots with growing conditions. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 3, 3-14 (2023). https://doi.org/10.34984/SCFTP.2023.18.3.001
Key words: mixed oxides, synthesis, lanthanum aluminate, lanthanum oxide, structure, water fluid, catalysts, methane oxidation
The synthesis of mixed La—Al-oxide systems with the atomic ratio La : Al 1 : 1 was studied. At the first stage, the dried mass containing La and Al nitrates and starch was burned. Heat treatment of the resulting amorphous product at a temperature of 700°C leads to the formation of LaAlO3 aluminate with a cubic perovskite structure. The composition and morphology of the product formed during subsequent processing in a water fluid (WF, density 0.2 g/cm3, 415°C) medium depends on the degree of ordering of the precursor. Crystalline LaAlO3 (cubic) in a WF medium undergoes additional ordering with a decrease in the specific surface area (Ssp.) while maintaining the crystalline structure; further calcination at 900°C does not lead to a change in the value of Ssp. and structure. When processing an amorphous precursor in a WF medium, the value of Ssp. increases and a mixture of LaAlO3 aluminates of cubic and orthorhombic structure and La and Al hydroxides is formed. Further calcination at 900°C leads to the formation of a mixture of LaAlO3 (cub.), La2O3 (hex.) and, possibly, X-ray amorphous Al2O3. The synthesized systems were studied as catalysts for methane oxidation. There was no correlation between activity and selectivity for oxidative coupling products (ethane ethylene) with the value of Ssp., but their dependence on the phase composition of the mixed La—Al-oxide was established. The systems that underwent intermediate treatment in a WF environment and contained the LaAlO3 (cub.) and La2O3 (hex.) phases turned out to be the most efficient. The results obtained indicate the high structural sensitivity of the catalytic process parameters.
doi:10.34984/SCFTP.2023.18.2.006
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7.0.100-2018
Synthesis of mixed La—Al-oxides using treatment in water fluid and their catalytic properties in methane oxidation / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2023. – Т. 19. – № 2. – С. 87-102. - DOI: 10.34984/SCFTP.2023.18.2.006
TRANSLIT
Sintez smeshannyh La—Al-oksidov s ispol'zovaniem obrabotki v srede vodnogo flyuida i ih kataliticheskie svojstva v processe okisleniya metana / – Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2023. – Т. 19. – № 2. – S. 87-102. - DOI: 10.34984/SCFTP.2023.18.2.006
En
Synthesis of mixed La—Al-oxides using treatment in water fluid and their catalytic properties in methane oxidation. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 2, 87-102 (2023). https://doi.org/10.34984/SCFTP.2023.18.2.006
Key words: adsorption, impregnation, supercritical fluid, N,N,NАК,NАК-tetraoctyl diglycolamide, solid phase extraction
In this study, the adsorption isotherms of N,N,N’,N’-tetraoctyl diglycolamide (TODGA) on three types of hypercrosslinked polystyrene (HCP) in supercritical CO2 were measured by gravimetric analysis. It is shown that under equal conditions (T = 313.15 K, P = 20 MPa), MN200 and MN202 HCPs adsorb up to 0.55 mmol/g and 0.59 mmol/g TODGA respectively, which allows them to be applied as the ligand carrier. The adsorption of TODGA on MN270 under the same conditions did not exceed 0.07 mmol/g. Also the temperature and medium density effect on the TODGA adsorption on MN200 was evaluated. It is shown that isothermal decreasing of the CO2 density can increase the saturated adsorption of TODGA. The solid phase extractant (SPE) based on MN202 and TODGA did not show extraction properties towards Nd3+, which is probably due to the matrix insufficient pore size for the formation of comparatively large complex compound. At the same time, SPE based on MN200 showed a potential feasibility of its use.
doi:10.34984/SCFTP.2023.18.2.005
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ГОСТ
7.0.100-2018
Solid phase extractants based on tetraoctyl diglycolamide and hypercrosslinked polystyrene: formation in supercritical carbon dioxide media / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2023. – Т. 19. – № 2. – С. 74-86. - DOI: 10.34984/SCFTP.2023.18.2.005
TRANSLIT
Tverdye ekstragenty na osnove tetraoktildiglikolamida i sverhsshitogo polistirola: poluchenie v srede sverhkriticheskogo dioksida ugleroda / – Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2023. – Т. 19. – № 2. – S. 74-86. - DOI: 10.34984/SCFTP.2023.18.2.005
En
Solid phase extractants based on tetraoctyl diglycolamide and hypercrosslinked polystyrene: formation in supercritical carbon dioxide media. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 2, 74-86 (2023). https://doi.org/10.34984/SCFTP.2023.18.2.005
Key words: thermodynamic modelling, Peng-Robinson and CPA (Cubic Plus Association) equation of state, acetylsalicylic acid, salbutamol sulfate, ethanol, dimethylsulfoxide
Thermodynamic modeling of pharmaceutical drugs solubility in supercritical fluids is necessary of optimization of extraction, purification, micronization and other processes. The CO2-ethanol-aspirin and CO2—dimethylsulfoxide (DMSO)—salbutamol sulfate ternary systems were used to show possibility of application of simplified models based on Peng—Robinson cubic equation of state. They were used for descri ption of phase equilibria in the CO2—ethanol binary subsystem at p=0.1—12 MPa and T = 290—345 K and in the CO2—DMSO binary subsystem at p = 0.5—18 MPa and T = 275—350 K. In the case of ternary systems, the data on the pharmaceuticals solubility in the mixed solvents were successfully approximated. Existing data at p = 7.5—35 MPa, T = 298—328 K, x(C2H5OH) = 0 and 3 mol. % were used for aspirin. Salbutamol sulfate solubility in the CO2—DMSO mixture was measures in this work at p = 8.6—21.7 MPa and T = 313—323 K by means of visual method in the thermostatic cell of constant volume. Although the obtained models describe phase equilibria, they disagree with fluid density data, especially for composition that are rich with polar components. Nevertheless, it doesn’t cause problems with usage of cubic equations of state for description of pharmaceuticals solubility in the fluid-based systems.
doi:10.34984/SCFTP.2023.18.2.004
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7.0.100-2018
Some methodological aspects of solid phase–supercritical fluid equilibria modeling / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2023. – Т. 19. – № 2. – С. 61-73. - DOI: 10.34984/SCFTP.2023.18.2.004
TRANSLIT
Nekotorye metodologicheskie aspekty modelirovaniya ravnovesij tverdaya faza— sverhkriticheskij flyuid / – Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2023. – Т. 19. – № 2. – S. 61-73. - DOI: 10.34984/SCFTP.2023.18.2.004
En
Some methodological aspects of solid phase–supercritical fluid equilibria modeling. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 2, 61-73 (2023). https://doi.org/10.34984/SCFTP.2023.18.2.004
Key words: SCF-micronization, RESS, levofloxacin hemihydrate, levofloxacin monohydrate, trifluoromethane
Micronization of levofloxacin hemihydate drug substance (LFC) by RESS using trifluoromethane (CHF3) as a polar supercritical solvent was investigated. By scanning electron microscopy, it was shown that at CHF3 temperature of 50°C, micronized LFC particles have the form of submicron-sized microbeads. At a temperature of 100°C, the particles take the form of thin (less than 0.1 microns) elongated plates with rounded edges. At this temperature, an increase in CHF3 pressure from 20 MPa to 35 MPa increases the average particle size of these particles from 1 to 2 um, respectively. X-ray phase analysis of samples obtained at 50 °C showed the identity of the original and micronized LFC substance corresponding to the structure of levofloxacin hemihydrate — С36Н40F2N6O8⋅H2O. At the same time, it was shown that an increase in the process temperature to 100°C leads to the appearance of one of its polymorphic forms, levofloxacin monohydrate С18Н20F2N3O4⋅H2O in the micronized LFC.
doi:10.34984/SCFTP.2023.18.2.003
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7.0.100-2018
Micronization of levofloxacin hemihydrate using supercritical trifluoromethane / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2023. – Т. 19. – № 2. – С. 52-60. - DOI: 10.34984/SCFTP.2023.18.2.003
TRANSLIT
Mikronizaciya levofloksacina polugidrata s ispol'zovaniem sverhkriticheskogo triftormetana / – Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2023. – Т. 19. – № 2. – S. 52-60. - DOI: 10.34984/SCFTP.2023.18.2.003
En
Micronization of levofloxacin hemihydrate using supercritical trifluoromethane. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 2, 52-60 (2023). https://doi.org/10.34984/SCFTP.2023.18.2.003
Key words: supercritical conditions, сверхкритические условия, imperfect reaction systems, theory of absolute reaction rates, lattice-gas model
The review of the works devoted to modeling of the processes and physical — chemical properties is given. Specificity SCF and their role in technologies is discussed. The list of nonequilibrium and equilibrium processes in which methods of mathematical modeling have been involved is resulted. Nonequilibrium processes are grouped as the equation of chemical kinetics, hydrodynamic models and the diffusion equations,and also the description of distributions nanoparticles and phenomenological models. Equilibrium models cover an existing spectrum of treatments of experimental data from thermodynamic to the microscopic models providing the account of nonideal reactionary systems, and also with attraction of a method of molecular dynamics and energy calculations methods of quantum chemistry. The greatest attention in works is given to the equations of states for SCF and their modeling at the molecular level taking into account a presence of multicomponent mixes and specificity of interaction of components, including them asymmetry. As a whole, two areas of appendices of the equations of states concerning extensive area of thermodynamic parameters in a wide range of change of pressure and temperatures out of area of rarefied gas, and, actually, nearby-critical area are allocated. Real processes are realised out of nearby-critical area in which they are braked, in systems with the raised density of components. For modelling of processes in SCF the common approach providing self-agreement descriptions of equilibrium and kinetics of studied processes on the basis of the molecular description by means of the lattice-gas model is offered.
doi:10.34984/SCFTP.2023.18.2.002
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ГОСТ
7.0.100-2018
Modeling of Processes and Physico-Chemical Properties of Fluids in Near- and Supercritical Regions of State Parameters / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2023. – Т. 18. – № 2. – С. 9-51. - DOI: 10.34984/SCFTP.2023.18.2.002
TRANSLIT
Modelirovanie processov i fiziko-himicheskih svojstv flyuidov v okolo- i sverhkriticheskoj oblastyah parametrov sostoyaniya / – Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2023. – Т. 18. – № 2. – S. 9-51. - DOI: 10.34984/SCFTP.2023.18.2.002
En
Modeling of Processes and Physico- Chemical Properties of Fluids in Near- and Supercritical Regions of State Parameters. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 2, 9-51 (2023). https://doi.org/10.34984/SCFTP.2023.18.2.002
Key words: supercritical carbon dioxide, subcritical carbon dioxide, poly-D,L-lactide, polymethylmethacrylate, electron spin resonance spectroscopy, 2,2,6,6-tetramethyl-piperidine-1-oxyl, spin probe, diffusion coefficient, spin-spin exchange interactions, distribution constant, supercritical fluid chromatography
The rotational and translational coefficients of the TEMPONE spin probe mobility were studied by ESR spectroscopy in the PLA and PMMA-based polymers plasticized with supercritical as well as subcritical carbon dioxide. Translational diffusion coefficients of TEMPONE in the PMMA-SC-CO2, system are 3 times inferior in comparison to PLA-SC-CO2 and the corresponding values are of 10-14 and 10-11 m2/s order of magnitude. The rotation activation energy of a value 22±5 kJ/mole was determined for the TEMPONE rotation in PLA-SC-CO2. It was found out that desorption of the radical exceeds TEMPONE diffusion into bulk PLA under subcritical conditions during the experimental period. Spectra of TEMPONE in PLA-SUB-CO2 turned out to be a superposition of two signals: a narrow one, which is similar to that of TEMPONE in PLA-SC-CO2, and a broad isotropic one caused by the TEMPONE paramagnetic particles accumulation in a polymer volume proximate to the surface. As local concentration decreases with time, the rotational anisotropy is exposed in the latter signal. The study gives an outlook on the SC-CO2 use as promising media to the polymer impregnation primarily taking into consideration both it’s and solutes’ higher mass diffusivity.
doi:10.34984/SCFTP.2023.18.1.005
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ГОСТ
7.0.100-2018
The diffusion of tempone spin probe in poly-D,L-lactide and polymethylmethacrylate plasticized with sub- and supercritical carbon dioxide / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2023. – Т. 1. – № 1. – С. 63-86. - DOI: 10.34984/SCFTP.2023.18.1.005
TRANSLIT
Diffuziya spinovogo zonda TEMPON v plastificirovannyh sub- i sverhkriticheskim CO2 polimetilmetakrilate i poli-D, L-laktide / – Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2023. – Т. 1. – № 1. – S. 63-86. - DOI: 10.34984/SCFTP.2023.18.1.005
En
The diffusion of tempone spin probe in poly-D,L-lactide and polymethylmethacrylate plasticized with sub- and supercritical carbon dioxide. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 1, 63-86 (2023). https://doi.org/10.34984/SCFTP.2023.18.1.005
Key words: subcritical water, extraction, Japanese sophora buds, polyphenols, inhibition of acetylcholinesterase
The extraction of Japanese sophora buds (Sophora japonica) (BS) was carried out using a subcritical water medium (SBW) within a temperature of 120—220°C, as well as by the traditional water-ethanol method. Evaluation of the polyphenolic composition of extracts and the activity of acetylcholinesterase (AChE) inhibition for products isolated by various methods showed that the SBW extract obtained at a temperature of 220°C demonstrates the highest values in terms of the sum of polyphenols and the sum of flavonoids, both in comparison with the extract obtained by the traditional method and with SBW extracts, isolated at lower temperatures. At the same time, among the studied products, SBW extract (temperature 220°C) shows the highest activity in inhibiting AHE, which indicates the determining role of the sum of polyphenols in the composition of BS extracts.
doi:10.34984/SCFTP.2023.18.1.004
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ГОСТ
7.0.100-2018
Evaluation of the dependence of the polyphenolic composition and the activity of acetylcholinesterase inhibition of extracts of japanese sophora buds (SOPHORA JAPONICA) on the extraction method / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2023. – Т. 1. – № 1. – С. 52-61. - DOI: 10.34984/SCFTP.2023.18.1.004
TRANSLIT
Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2023. – Т. 1. – № 1. – S. 52-61. - DOI: 10.34984/SCFTP.2023.18.1.004
/ –En
Evaluation of the dependence of the polyphenolic composition and the activity of acetylcholinesterase inhibition of extracts of japanese sophora buds (SOPHORA JAPONICA) on the extraction method. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 1, 52-61 (2023). https://doi.org/10.34984/SCFTP.2023.18.1.004
Key words: supercritical carbon dioxide, resorcinol-formaldehyde aerogels, ferrocene
An efficient method for the synthesis of hybrid resorcinol-formaldehyde aerogels with ferrocene subunit fragments embedded in their polymer structure has been developed. In the process of gel formation preceding the production of aerogels, dioxane was used for the first time as the main reaction solvent. The conversion of gels into aerogels was carried out using SC-CO2). Aerogel samples were characterized in detail by Mossbauer spectroscopy, nitrogen adsorption, and atomic absorption spectroscopy, and the density of materials was determined. The iron content in the resulting aerogels varies in the range of 1.5—11 % by weight of iron (or 5.3—35 % by weight of ferrocene units). Metallocene subunits are present in aerogels in two valence-oxidative states: ferrocene and ferrocenium.
doi:10.34984/SCFTP.2023.18.1.003
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ГОСТ
7.0.100-2018
Ferrocene-modified resorcinol-formaldehyde aerogels / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2023. – Т. 1. – № 1. – С. 38-51. - DOI: 10.34984/SCFTP.2023.18.1.003
TRANSLIT
Modificirovannye ferrocenom rezorcin-formal'degidnye aerogeli / – Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2023. – Т. 1. – № 1. – S. 38-51. - DOI: 10.34984/SCFTP.2023.18.1.003
En
Ferrocene-modified resorcinol-formaldehyde aerogels. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 1, 38-51 (2023). https://doi.org/10.34984/SCFTP.2023.18.1.003
Key words: sub- and supercritical fluid extraction, ethanol, tinder fungus, fomes fomentarius, chitin-containing complex.
Chitin-containing complexes were obtained from the fruiting body of the tinder fungus Fomes fomentarius using sub- and supercritical fluid extraction with ethanol with a yield of 57—88 % and a chitin content of up to 18.7 %. The influence of the duration, temperature, and pressure of extraction on the yield and properties of the resulting chitin containing complexes has been evaluated. Chitin-containing complexes were characterized by elemental and functional (by IR spectroscopy) composition. The high sorption capacity of the obtained complexes in relation to the basic — methylene blue (up to 312 mg/g) and acid — congo red (up to 170 mg/g) dyes is shown. Sorption activity relative to both basic and acid dyes indicates the polyampholytic nature of the resulting complexes-biosorbents.
doi:10.34984/SCFTP.2023.18.1.002
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ГОСТ
7.0.100-2018
Obtaining chitin-containing complexes from the fruit body of the FOMES FOMENTARIUS fungus using sub- and supercritical extraction methods / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2023. – Т. 1. – № 1. – С. 24-37. - DOI: 10.34984/SCFTP.2023.18.1.002
TRANSLIT
Poluchenie hitinsoderzhashchih kompleksov iz plodovogo tela griba FOMES FOMENTARIUS metodami sub- i sverhkriticheskoj ekstrakcii / – Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2023. – Т. 1. – № 1. – S. 24-37. - DOI: 10.34984/SCFTP.2023.18.1.002
En
Obtaining chitin-containing complexes from the fruit body of the fomes fomentarius fungus using sub- and supercritical extraction methods. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 1, 24-37 (2023). https://doi.org/10.34984/SCFTP.2023.18.1.002
Key words: supercritical drying, aerogel, chitosan, protein, pharmaceutical compositions, drug delivery systems
Protein (egg white) and chitosan aerogel microparticles characterized by low density, developed morphology and high specific surface area, high porosity, large volume and small pore diameter, were obtained. Using the laser diffraction method, particle size distribution curves were obtained, from which the average number and aerodynamic diameters were calculated. The aerodynamic diameter of all obtained biopolymer aerogels lies in the range required for targeted delivery of active pharmaceutical ingredients (APIs) to the olfactory region of the nasal cavity. Experimental studies have been carried out on the introduction of API «melatonin» into the pores of biopolymer aerogels at the stages of solvent replacement and supercritical adsorption. Mass fractions of API in the resulting pharmaceutical compositions «biopolymer aerogel — API» were determined by high-performance liquid chromatography. X-ray powder diffraction showed that API in pharmaceutical compositions is present mainly in the amorphous state. The results of in vivo experimental studies showed that in the case of intranasal administration of both «biopolymer aerogel — API» compositions, the maximum concentration of API in brainтtissues is reached after 30 minutes. This proves that the resulting biopolymer aerogels based on protein (egg white) and chitosan are promising for use as API carrier matrices in the development of nasal drug delivery systems.
doi:10.34984/SCFTP.2023.18.1.001
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ГОСТ
7.0.100-2018
Biopolymer aerogels as nasal drug delivery systems / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2023. – Т. 1. – № 1. – С. 2-23. - DOI: 10.34984/SCFTP.2023.18.1.001
TRANSLIT
Biopolimernye aerogeli kak nazalnye sistemy dostavki lekarstv / – Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2023. – Т. 1. – № 1. – S. 2-23. - DOI: 10.34984/SCFTP.2023.18.1.001
En
Biopolymer aerogels as nasal drug delivery systems. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 1, 2-23 (2023). https://doi.org/10.34984/SCFTP.2023.18.1.001