Key words: polymer films, biodegradation, subcritical Freon R22, ecology, microorganisms
For the first time method of increasing the biodegradability of polymer films (LDPE) by the impregnation of polymer with the olive oil (model of food waste, so called “cooking oil”) has been proposed. For polymer modification subcritical (temperature 90 °C, pressure 280 bar) Freon R22 (difluorochloromethane) was used.Testing of polymers during 6 months under abnormally high temperature and humidity (Hoa Lack, Vietnam) demonstrated that biodegradation ratio of oil impregnated films was 3 times higher that of control samples. Identification of destructing microorganisms from testing films has been realized. Investigations show that proposed method may be perspective for solving the problem of polymer waste degradation in nature.
doi:10.34984/SCFTP.2019.14.2.001
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ГОСТ
7.0.100-2018
Development of Polymer Waste Impregnation Method in Subcritical Freon R22 Media with Substances Promoting their Biodegradation in Nature / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2019. – Т. 14. – № 2. – С. 4-13. - DOI: 10.34984/SCFTP.2019.14.2.001
TRANSLIT
Razrabotka metoda impregnacii polimernyh othodov v subkriticheskom freone R22 veshchestvami, sposobstvuyushchimi ih biorazlozheniyu v estestvennoj srede / – Tekst : neposredstvennyj // Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2019. – Т. 14. – № 2. – S. 4-13. - DOI: 10.34984/SCFTP.2019.14.2.001
En
Development of Polymer Waste Impregnation Method in Subcritical Freon R22 Media with Substances Promoting their Biodegradation in Nature. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 2, 4-13 (2019). https://doi.org/10.34984/SCFTP.2019.14.2.001
Key words: «one-pot», roots of Aralia mandshurica, oleanolic acid, HPLC, subcritical water
The presented work is aimed at the development a «one-pot»-technique for production oleanolic acid (OA) from the roots of Aralia mandshurica Aralia mandshurica Rupr. using the subcritical water (SBW). For the first time SBW that serves as a reactant and a solvent has been used to obtain OA in good yields starting from the roots of of Aralia mandshurica. This method of preparation of OA allows one to avoid the use of toxic organic solvents. The good yields of the targeted OA can be obtained for the period of time which is 16 times shorter than needed by the traditional procedures.
doi:10.34984/SCFTP.2019.14.2.002
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ГОСТ
7.0.100-2018
«One-pot»-Technique for Production of Oleanolic Acid from the Roots of <i>Aralia mandshurica</i> by Subcritical Water / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2019. – Т. 14. – № 2. – С. 14-22. - DOI: 10.34984/SCFTP.2019.14.2.002
TRANSLIT
«One-pot»-metodika polucheniya oleanolovoj kisloty iz kornej aralii man'chzhurskoj v srede subkriticheskoj vody / – Tekst : neposredstvennyj // Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2019. – Т. 14. – № 2. – S. 14-22. - DOI: 10.34984/SCFTP.2019.14.2.002
En
«One-pot»-Technique for Production of Oleanolic Acid from the Roots of <i>Aralia mandshurica</i> by Subcritical Water. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 2, 14-22 (2019). https://doi.org/10.34984/SCFTP.2019.14.2.002
Key words: hydrogen, self-ignition, saturated water vapor, carbon dioxide
The peculiarities of hydrogen combustion in its stoichiometric mixtures with oxygen diluted with water vapor, carbon dioxide, and nitrogen at ∼2.6 MPa is investigated for the first time. The experiments were carried out at slow uniform heating (1 K/min) in a tubular stainless steel reactor in which the process occurs via the conjugate heterogeneous (over the reactor wall) and homogeneous (in the volume of the reaction mixture) oxidation reactions. Heterogeneous oxidation of H2 prevailed in the N2 and CO2 media, while homogeneous oxidation was predominant in the H2O medium. Based on time dependencies of temperature rise caused by the exothermic oxidation of hydrogen, it is found that the self-ignition temperature of H2/O2/N2 and H2/O2/H2O mixtures is by about 30 K lower than that of the H2/O2/CO2 mixture. It is shown that a small addition of water to the H2/O2/N2 and H2/O2/CO2 mixtures leads to a decrease in the self-ignition temperature.
doi:10.34984/SCFTP.2019.14.2.003
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ГОСТ
7.0.100-2018
Conjugated Processes of Heterogeneous-Homogeneous Oxidation of Hydrogen in High-Density H<sub>2</sub>/O<sub>2</sub>/H<sub>2</sub>O, H<sub>2</sub>/O<sub>2</sub>/CO<sub>2</sub> and H<sub>2</sub>/O<sub>2</sub>/N<sub>2</sub> Mixtures / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2019. – Т. 14. – № 2. – С. 23-30. - DOI: 10.34984/SCFTP.2019.14.2.003
TRANSLIT
Sopryazhennye processy geterogenno-gomogennogo okisleniya vodoroda v vysokoplotnyh smesyah H2/O2/H2O, H2/O2/CO2 i H2/O2/N2 / – Tekst : neposredstvennyj // Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2019. – Т. 14. – № 2. – S. 23-30. - DOI: 10.34984/SCFTP.2019.14.2.003
En
Conjugated Processes of Heterogeneous-Homogeneous Oxidation of Hydrogen in High-Density H<sub>2</sub>/O<sub>2</sub>/H<sub>2</sub>O, H<sub>2</sub>/O<sub>2</sub>/CO<sub>2</sub> and H<sub>2</sub>/O<sub>2</sub>/N<sub>2</sub> Mixtures. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 2, 23-30 (2019). https://doi.org/10.34984/SCFTP.2019.14.2.003
Key words: supercritical carbon dioxide, cyclization, benz-1,3-azol-2-ones, tin(II) derivatives
It was demonstrated that tin(II) 2-ethylhexanoate and tin(II) oxide are effective catalysts for the reaction of cyclization of model arylamines o-NH2(C6H4)XH (X = NH, O, S, CH2NH) in supercritical carbon dioxide with the formation of benzo-1,3-azol-2- ones and 3,4-dihydroquinazolin-2-one. Optimal conditions for these reactions were found. Possible mechanisms for these processes are proposed depending on the used catalyst.
doi:10.34984/SCFTP.2019.14.2.004
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ГОСТ
7.0.100-2018
Cyclization of <i>o</i>-phenylenediamine and <i>o</i>-substituted Anilines with Carbon Dioxide in Supercritical State / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2019. – Т. 14. – № 2. – С. 31-39. - DOI: 10.34984/SCFTP.2019.14.2.004
TRANSLIT
Ciklizaciya o-fenilendiamina i o-zameshchennyh anilinov s dioksidom ugleroda v sverhkriticheskom sostoyanii / – Tekst : neposredstvennyj // Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2019. – Т. 14. – № 2. – S. 31-39. - DOI: 10.34984/SCFTP.2019.14.2.004
En
Cyclization of <i>o</i>-phenylenediamine and <i>o</i>-substituted Anilines with Carbon Dioxide in Supercritical State. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 2, 31-39 (2019). https://doi.org/10.34984/SCFTP.2019.14.2.004
Key words: supercritical carbon dioxide, solubility, Peng-Robinson equation, saturated vapor pressure
The influence of the method of determining the vapor pressure of various substances on the accuracy of the descri ption of their solubilities in supercritical carbon dioxide is studied. It is shown that in most cases the computational methods of Clapeyron, Lee—Kesler, Riedel, Frost—Kolkuorf—Todos and Riedel—Plank—Miller do not allow the experimental data to be described with acceptable (up to 10—12 %) accuracy. The accuracy of the solubility descri ption is significantly increased by using the saturated vapor pressure as the second fitting parameter in addition to the coefficient of binary interaction. It is suggested to use the described approach to indirectly determine the saturated vapor pressure of substances through the descri ption of their solubilities. It is shown that the results obtained using this approach are much better consistent with the experimental data than those obtained by the above mentioned calculation methods.
doi:10.34984/SCFTP.2019.14.2.005
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ГОСТ
7.0.100-2018
Description of Solubility in Supercritical Carbon Dioxide as a Method to Determine Saturated Vapor Pressure of Desolved Substances / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2019. – Т. 14. – № 2. – С. 40-66. - DOI: 10.34984/SCFTP.2019.14.2.005
TRANSLIT
Opredelenie davleniya nasyshchennyh parov veshchestv na osnove opisaniya ih rastvorimosti v sverhkriticheskom diokside ugleroda / – Tekst : neposredstvennyj // Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2019. – Т. 14. – № 2. – S. 40-66. - DOI: 10.34984/SCFTP.2019.14.2.005
En
Description of Solubility in Supercritical Carbon Dioxide as a Method to Determine Saturated Vapor Pressure of Desolved Substances. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 2, 40-66 (2019). https://doi.org/10.34984/SCFTP.2019.14.2.005
Key words: iodine, solubility, carbon dioxide, subcritical conditions, supercritical conditions, iodometric analysis
The solubility of iodine in sub- and supercritical carbon dioxide was studied using a flow-type extraction setup. It is shown that at 20—80 °C and 60—350 atm, the solubility of iodine increases at rising temperature and CO2 pressure and the mole fraction of iodine in its saturated solution ranges from 0,12 · 10-3 to 1,42 · 10-3.
doi:10.34984/SCFTP.2019.14.2.006
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ГОСТ
7.0.100-2018
Solubility of malonic and succinic acids in CO2-solvent mixtures and micronization via supercritical antisolvent precipitation / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2019. – Т. 14. – № 2. – С. 67-72. - DOI: 10.34984/SCFTP.2019.14.2.006
TRANSLIT
Issledovanie rastvorimosti ioda v sub- i sverhkriticheskom diokside ugleroda / – Tekst : neposredstvennyj // Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2019. – Т. 14. – № 2. – S. 67-72. - DOI: 10.34984/SCFTP.2019.14.2.006
En
Solubility of Iodine in Sub/Supercritical Carbon Dioxide. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 2, 67-72 (2019). https://doi.org/10.34984/SCFTP.2019.14.2.006
Key words: adiabatic calorimeter, asymmetryparameter, benzene, critical amplitude, critical point, isochoric heat capacity, Yang—Yang anomaly parameter
Single- (\(C_{V_1}\)) and two-phase (\(C_{V_2}\)) isochoric heat capacities, densities (\(\rho_S\)), and phasetransition temperatures (\(T_S\)) of benzene were measured in the critical and supercritical regions. Measurements were made in the immediate vicinity of the liquid—gas phase transition and the critical point in order to accurately determine the phase transition properties (\(T_S\), \(\rho_S\), \(C_{V_1}\) and \(C_{V_2}\)). The measurements have been made over the temperature range from 347 to 616 K for 6 liquid and 5 vapor isochores between 265 and 653 kg · m-3 at pressures up to 7,5 MPa. The measurements were performed using a high-temperature, high-pressure, nearly constant-volume adiabatic calorimeter. The combined expanded uncertainty of the measurements of density, temperature, and isochoric heat capacity, \(C_{V}\), at the 95 % confidence level with a coverage factor of k = 2 is estimated to be 0,15%, 15 mK, and 3,0 %, respectively. The measured single- (\(C_{V_1}\)) and two-phase (\(C_{V_2}\)) isochoric heat capacities along the critical isochore and the saturated liquid (\(\rho'_S\)) and vapor (\(\rho''_S\)) densities near the critical point were used to accurately estimate the theoretically meaningful asymptotic critical amplitudes (\(A^+_0\) and \(B_0\)) and related amplitudes for other properties (\(\Gamma^+_0\), \(D_0\), \(\xi_0\)) as well as their universal relations, \(A^+_0/A^-_0\), \(A^+_0\Gamma^+_0B^2_0\), \(\alpha A^+_0\Gamma^+_0B^{-2}_0\), \(\xi_0\left(\frac{\alpha A^+_0}{\nu_C}\right)^{1/3}\). Saturated liquid and vapor densities together with measured two-phase \(C_{V_2}\) data were used to estimate the values of asymmetric parameters a3 («complete» scaling parameter) and b2 of the coexistence curve singular diameter. The experimentally determined asymptotical critical amplitudes \(A^+_0\) and \(B_0\) (fluid-specific parameters) were used to check and confirm the predictive capability of the universal correlation in terms of their dependence on the acentric factor ω, based on \(C_{V_2}\) as a function of the specific volume Valong various isotherms were used to calculate second temperature derivatives of the vapor-pressure \(\frac{d^2P_S}{dT^2}\) and chemical potential \(\frac{d^2\mu}{dT^2}\) and to estimate the value of Yang—Yang anomaly strength parameter \(R_\mu\) for benzene. The contributions of the vapor-pressure, \(C_{VP} = V_CT\frac{d^2P_S}{dT^2}\), and chemical potential, \(C_{V_\mu} = -T\frac{d^2\mu}{dT^2}\), to the measured total two-phase \(C_{V_2}\) were estimated.
doi:10.34984/SCFTP.2019.14.2.007
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ГОСТ
7.0.100-2018
Critical and Supercritical Phenomena in Benzene / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2019. – Т. 14. – № 2. – С. 73-104. - DOI: 10.34984/SCFTP.2019.14.2.007
TRANSLIT
Kriticheskie i sverhkriticheskie yavleniya v benzole / – Tekst : neposredstvennyj // Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2019. – Т. 14. – № 2. – S. 73-104. - DOI: 10.34984/SCFTP.2019.14.2.007
En
Critical and Supercritical Phenomena in Benzene. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 2, 73-104 (2019). https://doi.org/10.34984/SCFTP.2019.14.2.007
Key words: supercritical carbon dioxide, dispersed tungsten oxides, platinum nanoparticles, organometallic precursors, electron microscopy
A one-pot synthesis of dispersed platinum-tungsten composites was developed. Initially, using tungsten hexacarbonyl as a precursor in solution in supercritical CO2 in the presence of oxygen as an oxidizer promoting thermal decomposition of the precursor, dispersed particles of tungsten oxide with a grain size of about 100 nm and an aggregate size of 200–500 nm were synthesized. Then, these dispersed particles were used as a substrate for the subsequent deposition of platinum nanoparticles, which included two stages: 1) forming a film of an organometallic precursor by deposition from a solution in supercritical CO2 and 2) thermal decomposition of the precursor. As the two types of platinum precursors, the dimethyl(1,5-cyclooctadiene)platinum and platinum hexafluoroacetylacetonate, which both are soluble in sc CO2, were used as the typical ones in the practice of similar studies. The size of the formed platinum nanoparticles was 2.3 ± 0,7 nm using the former precursor and 3.5 ± 0,8 nm using the latter. The obtained composites are characterized by a relatively narrow size distribution of the noble metal nanoparticles and their uniform distribution over the surface of the particles of the dispersed carrier. Such materials may be of interest for (electro)catalysis tasks.
doi:10.34984/SCFTP.2019.14.2.008
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ГОСТ
7.0.100-2018
Formation of Dispersed Particles of Tungsten Oxide and Deposition of Platinum Nanoparticles on Them Using Organometallic Precursors From Solutions in Supercritical Carbon Dioxide / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2019. – Т. 14. – № 2. – С. 105-115. - DOI: 10.34984/SCFTP.2019.14.2.008
TRANSLIT
Formirovanie dispersnyh chastic oksida vol'frama i osazhdenie na nih platinovyh nanochastic s ispol'zovaniem metalloorganicheskih prekursorov iz rastvorov v sverhkriticheskom diokside ugleroda / – Tekst : neposredstvennyj // Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2019. – Т. 14. – № 2. – S. 105-115. - DOI: 10.34984/SCFTP.2019.14.2.008
En
Formation of Dispersed Particles of Tungsten Oxide and Deposition of Platinum Nanoparticles on Them Using Organometallic Precursors From Solutions in Supercritical Carbon Dioxide. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 2, 105-115 (2019). https://doi.org/10.34984/SCFTP.2019.14.2.008
Key words: water fluid, supercritical water, evaporation, condensation, hydrogen oxidation, kinetics, mechanism, catalysis
Some aspects of the experimental study of processes involving water fluids at temperatures approaching the critical (647 K) and above it in a static mode are considered. Particular attention is paid to the possible occurrence of artifacts and misinterpretations of the results associated with temperature gradients and uncontrolled effects of evaporation-condensation of water. The role of the walls of metal structural elements of the reactor (autoclave) as a catalyst for reactions involving water fluids and heat transfer processes on the measurements of thermal effects is analyzed. It is shown that a thermometric study of the dynamics of gas-phase reactions involving water vapor and supercritical fluid without measuring the pressure in the system and its chemical composition leads to uncertainty of the results and the inability to identify the most important kinetic features and mechanism of the process.
doi:10.34984/SCFTP.2019.14.2.009
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ГОСТ
7.0.100-2018
Some Methodological Aspects of the Study of Chemical Processes in Water Fluid Media / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2019. – Т. 14. – № 2. – С. 116-134. - DOI: 10.34984/SCFTP.2019.14.2.009
TRANSLIT
Nekotorye metodicheskie aspekty issledovaniya himicheskih processov v srede vodnyh flyuidov / – Tekst : neposredstvennyj // Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2019. – Т. 14. – № 2. – S. 116-134. - DOI: 10.34984/SCFTP.2019.14.2.009
En
Some Methodological Aspects of the Study of Chemical Processes in Water Fluid Media. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 2, 116-134 (2019). https://doi.org/10.34984/SCFTP.2019.14.2.009