Key words: light alkanes, methane, ethane, propane, conversion, oxidation, critical point, supercritical water
The features of light alkanes (LA) as prospective raw materials for production of bulk chemicals from natural gas are analyzed. The literature data on methane, ethane, and propane reactions in supercritical (SC) conditions are reviewed. It is demonstrated that both experimental studies of LA transformations under high temperatures and pressures (in supercritical water in particular) and description of their kinetics face serious difficulties. However, SC conditions provide with new opportunities due to specific trends in thermodynamic properties of substances in the nearest neighborhood of their critical point and in supercritical region.
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ГОСТ
7.0.100-2018
Oxidative Conversion of Light Alkanes in Supercritical Conditions: First Achievements, Problems, and Prospects / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2007. – Т. 2. – № 4. – С. 5-29. - DOI:
TRANSLIT
Okislitel'naya konversiya nizshih alkanov v sverhkriticheskih usloviyah: pervye rezul'taty, problemy, perspektivy / – Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2007. – Т. 2. – № 4. – S. 5-29. - DOI:
En
Oxidative Conversion of Light Alkanes in Supercritical Conditions: First Achievements, Problems, and Prospects. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 4, 5-29 (2007). https://doi.org/
Key words: ozone, ozonation of organic substances, supercritical carbon dioxide (SC-CO2), dicyclopentadiene
The new original procedure for preparative reactions of ozone with organic substrates in supercritical (SC) fluids as solvents is proposed. Reactions of ozone with o-isopropenylaniline and dicyclopentadiene as model substrates are investigated, and their products are identified using GC-MS, IR- and NMR-spectroscopies. It is demonstrated that in the case of reaction of ozone with o-isopropenylaniline SC-CO2 not only plays the role of efficient solvent for both ozone and organic substrate, but also stabilizes ozone (prevents its decomposition) and participates in the process as a co-reactant.
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ГОСТ
7.0.100-2018
Reactions of Ozone with Organic Substrates in Supercritical Carbon Dioxide / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2007. – Т. 2. – № 4. – С. 30-42. - DOI:
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Reakcii ozona s organicheskimi substratami v sverhkriticheskom diokside ugleroda / – Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2007. – Т. 2. – № 4. – S. 30-42. - DOI:
En
Reactions of Ozone with Organic Substrates in Supercritical Carbon Dioxide. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 4, 30-42 (2007). https://doi.org/
Key words: ZnO nanoparticles, synthesis, organic compounds, syngas, H2O and CO2 supercritical fluids
When studying oxidation of solid and liquid zinc (Zn)S,L by sub- and supercritical water, supercritical CO2 and mixture of H2O/CO2, formation of (ZnO)n nanoparticles was found out. We have called this process chemical re-condensation (ChR). According to our investigations, nanoparticles of 2÷100 nm, nanoneedles and nanorods with 10÷100-nm diameter and up to 50-µm length, and mechanically strong nanostructured ceramics are formed, depending on the conditions of ChR. The cluster mechanism of ChR triggering was suggested. Kinetic parameters of ChR of (Zn)S,L in H2O were determined. The higher rate of ChR in H2O in comparison with CO2 is probably caused by orientation of dipole molecules of H2O in the field of contact voltage at (Zn)S,L/(ZnO)n boundary and prolongation of the molecule life time at the absorbed state. At ChR of zinc in CO2 carbon is formed together with CO, and in H2O/CO2 mixtures paraffin and aromatic hydrocarbons, alcohols and formaldehyde are formed together with H2 and CO.
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7.0.100-2018
Formation of Nanostructured ZnO and Combustible Compounds at Reactions of Zinc with H2O and CO2 under Sub- and Supercritical Conditions / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2007. – Т. 2. – № 4. – С. 43-59. - DOI:
TRANSLIT
Obrazovanie nanostrukturirovannogo ZnO i goryuchih veshchestv pri reakciyah cinka s N2O i SO2 v sub- i sverhkriticheskih usloviyah / – Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2007. – Т. 2. – № 4. – S. 43-59. - DOI:
En
Formation of Nanostructured ZnO and Combustible Compounds at Reactions of Zinc with H2O and CO2 under Sub- and Supercritical Conditions. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 4, 43-59 (2007). https://doi.org/
Key words: supercritical n-pentane, catalytical isomerization, zeolite catalysts
The study of n-pentane isomerization under supercritical conditions over unmodified and Pt-modified acid catalysts (WO3- and H4[Si(W3O10)4]-loaded TiO2, different types of zeolites) was carried out in continuous flow reactor in the range of temperature 220÷350 °С and pressure 50÷130 atm, liquid hourly space velocity was varied between 6 and 30 h-1. Base acid catalysts were either not active (WO3/TiO2), or subjected to quick deactivation (H4[Si(W3O10)4]/TiO2). Their platinum modification leads to dramatic increase of total conversion up to 50% and to decrease of poison rate during 3÷5 hours. The most active and selective catalyst for n-pentane isomerization under supercritical conditions among examined zeolites systems was H-form of mordenite, but platinum modification decreases the catalyst activity. Process of cracking was prevailing over H-ZSM-5, but its modification with platinum leads to gain of iso-pentane yield.
Key words: supercritical n-pentane, catalytical isomerization, zeolite catalysts.
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7.0.100-2018
n-Pentane Isomerization under Supercritical Conditions over Pt-Modified Solid Acid Catalysts / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2007. – Т. 2. – № 4. – С. 60-69. - DOI:
TRANSLIT
Izomerizaciya n-pentana v sverhkriticheskih usloviyah na modificirovannyh platinoj tverdokislotnyh katalizatorah / – Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2007. – Т. 2. – № 4. – S. 60-69. - DOI:
En
n-Pentane Isomerization under Supercritical Conditions over Pt-Modified Solid Acid Catalysts. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 4, 60-69 (2007). https://doi.org/
Key words: supercritical supercritical water, brown coal, dynamic and static conversion
Conversion of brown coal was studied in supercritical water (SCW) at pressure P = 30 MPa and temperature T ≤ 760 °C at continuous supply of coal-water slurry (CWS) from above into a vertical tube reactor. It is shown that at coal particle fall into the reactor via a conic channel under the conditions of a continuous temperature increase (the stage of dynamic conversion (DC)) from 44 (at temperature in the reactor top TtR = 400°C) to 63 % (at TtR = 750°C) of organic matter of coal (OMC) are extracted from coal in the form of liquid and gaseous products with 71÷100 % of OMC oxygen. It is shown that DC of coal is resulted from conversion product drain under the action of excessive pressure of fluid in particles, caused by a rise of particle temperature at their fall into the reactor. It is determined that the main products of DC at TtR = 400°C are the high-molecular organic substances with prevalence of resins, and at 750°C they are alkanes, aromatic hydrocarbons, H2 and CO. It is important that after DC the coal particles have filled uniformly the reactor and they did not sinter at following static conversion (SC) of coal: at SCW pumping through the layer of coal particles in the reactor. The composition of products and rate of SC depends on the temperature of the process, in particular, due to the fact that water becomes the source of hydrogen even at T > 600°C.
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7.0.100-2018
Dynamic and Static Conversion of Brown Coal in Water under Supercritical Conditions / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2007. – Т. 2. – № 4. – С. 70-84. - DOI:
TRANSLIT
Dinamicheskaya i staticheskaya konversiya burogo uglya v vode pri sverhkriticheskih parametrah / – Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2007. – Т. 2. – № 4. – S. 70-84. - DOI:
En
Dynamic and Static Conversion of Brown Coal in Water under Supercritical Conditions. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 4, 70-84 (2007). https://doi.org/
Key words: biodiesel, bioethanol, supercritical media
Economical and technical aspects of liquid motor fuel production from renewable raw materials and its prospects for such technologies in Russia and worldwide are reviewed. The data on economical efficiency of bioethanol and biodiesel production in supercritical (SC) media are analyzed. Trans-esterification of vegetable and seed oils using SC methanol (ethanol) is compared with "conventional" catalytic process, and possible ways of cutting the production costs and rising the profitability of the process in SC media are discussed.
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ГОСТ
7.0.100-2018
Biofuel Production Using Supercritical Media as a Topical Problem of Present-Day Energetics / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2007. – Т. 2. – № 4. – С. 85-95. - DOI:
TRANSLIT
Proizvodstvo biotopliva s ispol'zovaniem sverhkriticheskih sred kak aktual'naya problema sovremennoj energetiki / – Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2007. – Т. 2. – № 4. – S. 85-95. - DOI:
En
Biofuel Production Using Supercritical Media as a Topical Problem of Present-Day Energetics. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 4, 85-95 (2007). https://doi.org/