Key words: fine-crystalline corundum, sub- and supercritical water, solid phase mobility, crystal formation, microcrystal size distribution, lognormal function, coalescence, surface spreading, recrystallization
A mechanism of the fine-crystalline corundum synthesis from aluminum hydroxide in the conditions of induced nucleation in the supercritical water fluid at 400°C, an initial pressure of 26.4 MPa, and subsequent exposure in a synthesis medium is considered. The size distribution of the crystals was based on the analysis of electron microscopic images. The use of the lognormal function to describe the crystal size distribution of the synthesized corundum particles is substantiated. The possibility of using the lognormal particle size distribution function and the time dependence of its parameters to reveal the formation routes of the product crystals is analyzed. It is found that the dimensional spectrum of microcrystals has four components, the appearance of which is associated with different routes of the product formation. The number of distribution components remains unchanged during the prolonged exposure, but their average characteristics have different time dependences. The redistribution of the mass during recrystallization, which leads, on the whole, to a decrease in the average crystal size, is explained by differences in the mobility of the crystal structure of different components. It is concluded that the states of corundum in the newly formed crystals and in the buildup layer on the particles of the inducing additive are different.
doi:10.34984/SCFTP.2018.13.1.001
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ГОСТ
7.0.100-2018
Analysis of a Fine-Crystalline Corundum Recrystallization in Supercritical Water Medium Using the Lognormal Particle Size Distribution Function / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2018. – Т. 13. – № 1. – С. 4-15. - DOI: 10.34984/SCFTP.2018.13.1.001
TRANSLIT
Analiz rekristallizacii melkokristallicheskogo korunda v sverhkriticheskoj vodnoj srede s pomoshch'yu lognormal'noj funkcii raspredeleniya chastic po razmeram / – Tekst : neposredstvennyj // Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2018. – Т. 13. – № 1. – S. 4-15. - DOI: 10.34984/SCFTP.2018.13.1.001
En
Analysis of a Fine-Crystalline Corundum Recrystallization in Supercritical Water Medium Using the Lognormal Particle Size Distribution Function. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 1, 4-15 (2018). https://doi.org/10.34984/SCFTP.2018.13.1.001
Key words: chamomile flowers, extraction, subcritical water, 7-methoxycoumarin, luteolin, apigenin, derivatization
UV-spectroscopy, gas chromatography / mass spectrometry, high efficiency liquid chromatography and gravimetry methods were employed to study the extracts of biologically active substances (BAS) from the flowers of chamomile growing in the Samara region. The extracts were obtained using the subcritical water and aqueous solutions of ethanol at 150 and 200 °C and 5 MPa. The BAS in the extracts were identified using a reactive gas chromatography.
doi:10.34984/SCFTP.2018.13.1.002
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ГОСТ
7.0.100-2018
Evaluation of Efficiency of Biologically Active Compounds Subcritical Extraction from the Chamomile Flowers (<i>Chamomilla recutita</i> R.) Growing in the Samara Region / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2018. – Т. 13. – № 1. – С. 16-33. - DOI: 10.34984/SCFTP.2018.13.1.002
TRANSLIT
Ocenka effektivnosti izvlecheniya biologicheski aktivnyh soedinenij ekstragentami v subkriticheskom sostoyanii iz cvetkov romashki aptechnoj (Chamomilla recutita R.), proizrastayushchej v Samarskoj oblasti / – Tekst : neposredstvennyj // Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2018. – Т. 13. – № 1. – S. 16-33. - DOI: 10.34984/SCFTP.2018.13.1.002
En
Evaluation of Efficiency of Biologically Active Compounds Subcritical Extraction from the Chamomile Flowers (<i>Chamomilla recutita</i> R.) Growing in the Samara Region. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 1, 16-33 (2018). https://doi.org/10.34984/SCFTP.2018.13.1.002
Key words: 1,4-dioxane, thermal stability
Thermal stability of 1,4-dioxane below and above its critical temperature (at 300— 500 °C) and at different fluid densities is studied. In the temperature range of 300— 350 °C dioxane is thermally stable during 80—100 minutes; at higher temperatures during the same time the uncontrolled pressure growth starts due to the thermal cracking of dioxane. The analysis of liquid and gas phases after the dioxane thermal treatment shows the formation of a wide range of products.
doi:10.34984/SCFTP.2018.13.1.003
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ГОСТ
7.0.100-2018
Thermal Stability of 1,4-Dioxane at Sub- and Supercritical Temperatures / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2018. – Т. 13. – № 1. – С. 34-39. - DOI: 10.34984/SCFTP.2018.13.1.003
TRANSLIT
Termicheskaya ustojchivost' 1,4-dioksana pri do- i sverhkriticheskih temperaturah / – Tekst : neposredstvennyj // Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2018. – Т. 13. – № 1. – S. 34-39. - DOI: 10.34984/SCFTP.2018.13.1.003
En
Thermal Stability of 1,4-Dioxane at Sub- and Supercritical Temperatures. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 1, 34-39 (2018). https://doi.org/10.34984/SCFTP.2018.13.1.003
Key words: supercritical carbon dioxide, diphenylamine, solubility, dynamic mode, SC-CO2-extraction
The results of experimental studies of solubility of diphenylamine in supercritical carbon dioxide (SC-CO2) are presented. Research was carried out at temperature 323.15 K in the pressure range from 10 to 35 MPa on the experimental plant implementing a dynamic research method, produced by «Reaction Engineering, Ink.» (South Korea). Experimental solubility data are described using the Peng — Robinson equation of state. The results of SC-CO2-extraction process of ether-ethanol mixture from the samples of «Sunar 308WIN» brand gunpowder are presented, and process parameters corresponding to the maximum preservation of diphenylamine in the powder are defined, the efficiency of this process is shown.
doi:10.34984/SCFTP.2018.13.1.004
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ГОСТ
7.0.100-2018
Extraction of Ether-Ethonol Mixture from Powders by the Example of Gunpowder Brand «Sunar 308WIN» Using Supercritical CO<sub>2</sub> / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2018. – Т. 13. – № 1. – С. 40-50. - DOI: 10.34984/SCFTP.2018.13.1.004
TRANSLIT
Ekstrakciya spirto-efirnoj smesi iz ohotnich'ih porohov s ispol'zovaniem sverhkriticheskogo SO2 na primere poroha «Sunar 308WIN» / – Tekst : neposredstvennyj // Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2018. – Т. 13. – № 1. – S. 40-50. - DOI: 10.34984/SCFTP.2018.13.1.004
En
Extraction of Ether-Ethonol Mixture from Powders by the Example of Gunpowder Brand «Sunar 308WIN» Using Supercritical CO<sub>2</sub>. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 1, 40-50 (2018). https://doi.org/10.34984/SCFTP.2018.13.1.004
Key words: ethylene-vinyl acetate copolymer, supercritical CO2, phase equilibrium, solubility, dispersing, SEDS method, crystallization
The results of an experimental study of the characteristics of phase equilibria for the systems consisting of toluene, supercritical carbon dioxide and ethylene-vinyl acetate copolymers (EVAC) are presented. The joint dispersing of different EVAC's and polyethylene using the SEDS method is performed at 8.0—25 MPa and 313, 323 and 333 K. A comparison of melting and crystallization processes in the mixtures of copolymers shows that those obtained by the SEDS method have higher degree of crystallinity as compared with the mixtures of the same compositions, but obtained by melt mixing.
doi:10.34984/SCFTP.2018.13.1.005
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ГОСТ
7.0.100-2018
Crystallization of Polymer Mixtures in the Course of their Dispersing Using the SEDS Method / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2018. – Т. 13. – № 1. – С. 51-63. - DOI: 10.34984/SCFTP.2018.13.1.005
TRANSLIT
Kristallizaciya polimernyh smesej v processe dispergirovaniya po metodu SEDS / – Tekst : neposredstvennyj // Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2018. – Т. 13. – № 1. – S. 51-63. - DOI: 10.34984/SCFTP.2018.13.1.005
En
Crystallization of Polymer Mixtures in the Course of their Dispersing Using the SEDS Method. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 1, 51-63 (2018). https://doi.org/10.34984/SCFTP.2018.13.1.005
Key words: supercritical antisolvent preci pitation, salbutamol, micronization, morphology, supersaturation degree
The applicability of the method of supercritical antisolvent preci pitation (SAS) to obtain microparticles of an anti-asthmatic salbutamol sulfate preparation suitable for the production of an inhalable dosage form is studied. Depending on the concentration of salbutamol in the starting solution, its flow rate and the pressure, spherical or needle shaped particles of 0.7 to 8.5 microns can be obtained. The dependence of the average particle size on the concentration of salbutamol in the initial solution is nonmonotonic. The conditions for the production of particles suitable in shape and size for the inhalation dosage form are determined.
doi:10.34984/SCFTP.2018.13.1.006
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ГОСТ
7.0.100-2018
Micronization of Salbutamol Sulfate by Supercritical Antisolvent Preci pitation: Effect of Process Parameters on Size and Morphology of Obtained Particles / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2018. – Т. 13. – № 1. – С. 64-76. - DOI: 10.34984/SCFTP.2018.13.1.006
TRANSLIT
Mikronizaciya sul'fata sal'butamola metodom sverhkriticheskogo antisol'ventnogo osazhdeniya: vliyanie parametrov processa na razmer i morfologiyu chastic / – Tekst : neposredstvennyj // Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2018. – Т. 13. – № 1. – S. 64-76. - DOI: 10.34984/SCFTP.2018.13.1.006
En
Micronization of Salbutamol Sulfate by Supercritical Antisolvent Preci pitation: Effect of Process Parameters on Size and Morphology of Obtained Particles. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 1, 64-76 (2018). https://doi.org/10.34984/SCFTP.2018.13.1.006
Key words: supercritical carbon dioxide, microencapsulation, pulsed supersonic jet, TiO2 nanoparticles
The process of microencapsulation of titanium dioxide nanoparticles in polyethylene glycol PEG 8000 at pulse expanding of the jets of polymer solution in supercritical carbon dioxide in vacuum and in a background gas (helium) is experimentally studied. In both cases, at given initial temperature and cosolvent (ethanol) concentration the distance from the nozzle exit to the point of «coil—globule» transition on the jet axis is determined using the electron microscopy data. The dependence of the transition point position on the initial temperature and the concentration of ethanol in the reactor is obtained.
doi:10.34984/SCFTP.2018.13.1.007
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ГОСТ
7.0.100-2018
«Coil—Globule» Transition During the Microencapsulation of TiO<sub>2</sub> Nanoparticles in the Jet of Supercritical CO<sub>2</sub> / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2018. – Т. 13. – № 1. – С. 77-85. - DOI: 10.34984/SCFTP.2018.13.1.007
TRANSLIT
Perekhod «klubok—globula» pri mikrokapsulirovanii nanochastic TiO2 v strue sverhkriticheskogo CO2 / – Tekst : neposredstvennyj // Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2018. – Т. 13. – № 1. – S. 77-85. - DOI: 10.34984/SCFTP.2018.13.1.007
En
«Coil—Globule» Transition During the Microencapsulation of TiO<sub>2</sub> Nanoparticles in the Jet of Supercritical CO<sub>2</sub>. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 1, 77-85 (2018). https://doi.org/10.34984/SCFTP.2018.13.1.007
Key words: impregnation, supercritical carbon dioxide, EPR, spin probe method, matrixes for tissue engineering.
The spin probe technique as a version of the electron paramagnetic resonance (EPR) spectroscopy was used to reveal the regularities of the formation of porous matrixes based on D,L-polylactide in a supercritical CO2 medium with the simultaneous impregnation by paramagnetic biologically active test molecule 4-Hydroxy-2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPOL). The dependences of the average and local dopant concentration on impregnation conditions were estimated. It was concluded that EPR spectroscopy is a promising method for studying porous polymeric materials formed in supercritical conditions. Impregnation of the polymer with a paramagnetic compound allows one to estimate the uniformity of the dopant distribution in a sample on both macroscopic and microscopic levels, and also to judge the structure of the polymer matrix. The data obtained by EPR and optical spectroscopy showed that the resulting matrixes meet the important requirements for porous materials for tissue engineering.
doi:10.34984/SCFTP.2018.13.1.008
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ГОСТ
7.0.100-2018
EPR Diagnostics of Porous Matrixes on the Basis of D,L-Polylactide, Generated in the Medium of Supercritical CO<sub>2</sub> / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2018. – Т. 13. – № 1. – С. 86-93. - DOI: 10.34984/SCFTP.2018.13.1.008
TRANSLIT
EPR diagnostika poristyh matriksov na osnove D,L-polilaktida, sformirovannyh v srede sverhkriticheskogo SO2 / – Tekst : neposredstvennyj // Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2018. – Т. 13. – № 1. – S. 86-93. - DOI: 10.34984/SCFTP.2018.13.1.008
En
EPR Diagnostics of Porous Matrixes on the Basis of D,L-Polylactide, Generated in the Medium of Supercritical CO<sub>2</sub>. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 1, 86-93 (2018). https://doi.org/10.34984/SCFTP.2018.13.1.008