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2017, №2

pp. 4-18

Articles

Compositions of Products of High-Sulfur Oil Shale Transformation in Supercritical Benzene

E.Yu. Kovalenko, Ya.Yu. Mel’nikov, T.A. Sagachenko, R.S. Min, Yu.F. Patrakov.

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Key words: oil shales, supercritical fluid extraction, pyrolysates, components, structure, composition

The conversion of high-sulfur oil shale in a supercritical benzene stream at 10 MPa and temperatures up to 400 °C is studied. The composition of the resulting liquid products was characterized by IR and 1H NMR spectroscopy, the structural group analysis and gas chromatography-mass-spectrometry. The content of resin-asphaltene substances in pyrolysates decreases, the content of aromatic fragments in their structure increases, while that of aliphatic fragments decreases at increasing temperature along with a decrease in the content of polar components in the oily fraction. The compounds identified in the oils are represented by normal and branched alkanes, alkenes, saturated or unsaturated naphthenes, mono-, bi-, tri-, tetra- and pentacyclic aromatic hydrocarbons, as well as by the thiophene, benzo-, dibenzo- and naphthobenzothiophene derivatives, ali phatic ethers and ketones.

2017, №2

pp. 19-25

Articles

Synthesis of Seco-Glaucine as a Model Study for Synthesis of Phenanthridone Alkaloids from Herbal Aporphine Alkaloids

E.V. Vetrova, S.V. Kurbatov, S.N. Borisenko, A.V. Lekar, S.S. Khizrieva, N.I. Borisenko, V.I. Minkin.

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Key words: subcritical water, aporphine alkaloids, glaucine, phenanthrene alkaloids, seco-glaucine, HPLC

The synthesis of phenanthrene alkaloid seco-glaucine from herbal aporphine alkaloid glaucine in subcritical water is studied at 100—250 °C with no catalytic additived. The maximum product yield (∼ 80 %) that is reached at 250 °C is virtually independent on the amount of the initial compound. The product can be directly preci pitated from the reaction mixture if its concentration is sufficiently high. No use of constly and toxic organic solvents is required.

2017, №2

pp. 26-34

Articles

Key words: Pelargonium graveolens, essential oil, supercritical fluid extraction

Optimal conditions (40 °C, 16 MPa, process duration 30 min) for the extraction of Pelargonium graveolens L’Her essential oil using supercritical (SC) carbon dioxide are determined. GC-MS analysis of the obtained product shows higher concentration of target components (e.g., citronellol, geraniol) in it compared to the oil obtained using a traditional method (steam distillation). Additional components, such as camphene, sabinene, etc., are also present in the product obtained via the extraction with SC-CO2.

2017, №2

pp. 35-48

Articles

Key words: supercritical fluids, aerogel, supercritical drying, homogenization, spraying

A complex study of the production of sodium alginate aerogel particles by emulsion gelation and dripping methods followed by drying in supercritical carbon dioxide. The factors that affect the characteristics of the obtained materials are determined. The above mentioned methods are tested on a semi-industrial level using high pressure homogenization and spraying through pneumatic nozzles. The resulting gel particles were dried in a supercritical carbon dioxide medium using the equipment of 0.25 and 2 L volume of drying vessels. The necessary characteristics and quality of the obtained aerogels do not decline at production scaling-up.

2017, №2

pp. 49-59

Articles

Modification of Poly(4-Methyl-2-Pentyne) in Supercritical Fluid Media for the Preparation of CO2-Selective Gas Separation Membranes

V.G. Polevaya, A.M. Vorobei, O.I. Pokrovskiy, G.A. Shandryuk, O.O. Parenago, V.V. Lunin, V.S. Khotimskiy.

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Key words: polymer membranes, gas separation, 1,2-disubstituted polyacetylenes, polymer chemical modification, СО2 separation, permeability, selectivity, quaternization

This work is devoted to the investigation of supercritical fluid media applicability for the modification of a promising gas-separating polymer in order to improve CO2-selectivity. The possibility to introduce a quaternary ammonium salt functional group into poly(4-methyl-2-pentyne) structure via two-stage process was demonstrated: bromination with N-bromosuccinimide and its subsequent addition to a tertiary amine (quaternization) in supercritical fluid media. Using trifluoromethane as a reaction media leads to the highest polymer modification degree. The best achieved result gave a three-fold increase in CO2/N2 selectivity in comparison with initial poly(4-methyl-2-pentyne).

2017, №2

pp. 60-67

Articles

Key words: osteoplastic material, bone block, supercritical carbon dioxide, deli pidization, bone, implants

An environmentally benign method for production of osteoplastic materials for reconstructive surgery based on the supercritical fluid extract with carbon dioxide is developed. The method ensures an efficient removal of li pids and li poids with minimal consumption of carbon dioxide and processing time at reduced production costs. It is optimized for the production of osteoplasty matrixes of xenogenic bone origin. The advantages of the obtained material in comparison with existing commercial analog in in vitro experiments are demonstrated.

2017, №2

pp. 68-80

Articles

Etching of Sapphire in Supercritical Water at Ultrahigh Temperatures and Pressures under the Conditions of Pulsed Laser Thermoplasmonics

M.Yu. Tsvetkov, N.V. Minaev, A.A. Akovantseva, G.I. Pudovkina, P.S. Timashev, S.I. Tsypina, V.I. Yusupov, A.E. Muslimov, A.V. Butashin, V.M. Kanevsky, V.N. Bagratashvili.

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Key words: sapphire, laser backside wet etching, microstructuring, thermoplasmonic, supercritical water, ultrahigh pressures and temperatures

For effective and well-controlled microstructuring of sapphire, the method of thermoplasmonic laser-induced backside wet etching (TPLIBWE) was applied. The method is based on the generation of highly absorbing silver nanoparticles generated in the course of the pulsed-periodic laser irradiation, which are formed as a result of laser destruction of AgNO3, a silver precursor dissolved in water. The process of sapphire etching is carried out by supercritical water at ultrahigh temperatures and pressures substantially exceeding the critical values for water and formed at the sapphire/water interface as a result of the absorption of laser pulses by silver nanoparticles. The mechanism of TPLIBWE is considered, the etching rates reaching ∼100 nm/pulse are determined. The formation of aluminum nanoparticles is revealed, which indicates the deep destruction of Al2O3 as a result of TPLIBWE.