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2016, №1

сс. 5-15

Editorial note

M.Yu. Sinev.

2016, №1

сс. 16-24

Articles

Synthesis of Carbon Nanotubes/Alumina Composites in Supercritical Media

R.Yu. Novotortsev, S.A. Chernyak, S.V. Savilov, V.V. Lunin.

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Key words: supercritical water, supercritical hexane, carbon nanotubes, alumina, nanomaterials, composite materials

Nanosized composites based on multiwall carbon nanotubes (CNT) and Al2O3 are
obtained in the supercritical (SC) media (water, hexane, and their mixture). Materials
of the same net composition are obtained by hydrothermal synthesis and sol-gel method
for comparison. The composites were characterized by electron microscopy, X-ray
diffraction and thermal analysis. The structure of materials synthesized in SC media
depends on the fluid composition. The most uniform composite containing the alumina
particles with the size comparable to the diameter of the CNT and stabilized on the
carbon surface can be obtained using a SC mixture of hexane and water as a medium. If
water and hexane are used separately, the formation of large alumina crystals on the
CNT surface, or the contamination of the composite by the products of hexane pyrolysis
and carbonization are respectively observed.

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2016, №1

сс. 25-31

Articles

Application of Sub- and Supercritical Freons in Xenogenic Bone Matrix Processing

D.Yu. Zalepugin, N.A. Tilkunova, I.V. Chernyshova, M.I. Vlasov.

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Key words: supercritical extraction, freons, carbon dioxide, xenogenic matrix

Sub- and supercritical freons can be successfully used in the bone matrix cleaning
process. In the case of freon R22 the duration of the bone matrix cleaning significantly
decreases as compared to the same procedure with supercritical carbon dioxide. Freons
R23, R134а and R407c which do not contain chlorine atoms, are practically ineffective
in this process.

doi:

2016, №1

сс. 32-42

Articles

Impregnation of Polymers with 2,2,6,6-Tetramethyl-4-Oxo-Piperidin-1-Oxyl (TEMPONE) Paramagnetic Probe in Sub- and Supercritical СО2

E.N. Golubeva, O.I. Gromov, N.A. Chumakova, E.D. Feklichev, M.Ya. Mel’nikov, V.N. Bagratashvili.

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Key words: supercritical СО2, polymers, impregnation, spin probes

Spin probe method is used to investigate the impregnation of polycarbonate (PC),
poly(ethylene oxide) (PEO) and cross-linked co-polymer of acrylamide and acrylic
acid (PAA) with organic molecules from sub- and supercritical CO2 media. The data
of the electron paramagnetic resonance (EPR) spectroscopy show that paramagnetic
molecules of 2,2,6,6-tetramethyl-4-oxo-pi peridin-1-oxyl (TEMPONE) at 196 bar and
307 K penetrate into polymers, which are in glassy (PC) and elastic (PEO) states. In
the same conditions impregnation of PAA with TEMPONE is negligible. Unlike in
PEO, local concentrations of TEMPON in PC are higher than average values, thus
demonstrating a much less uniform distribution of the probe in the latter polymer.
Temperature variations of EPR spectra indicate that rotational mobility of probe
molecules in PEO is higher than in PC. The obtained results demonstrate that the spin
probe method is a promising approach to study the features of the processes on microand
macro-levels in «polymer — supercritical solvent — organic additive» systems.

doi:

2016, №1

сс. 43-52

Articles

Key words: supercritical water; desulfurization; deasphaltization

The conversion of tar (gross-formula CH1.47N0.01S0.007) at its continuous supply into a
counter flow of supercritical water (SCW) at the gradient temperature variation
along the vertical axis of the tubular reactor (450 °С at the top, 650 °С at the bottom) at
30 MPa is studied. The yields of liquid products (LP) and volatile С1—С9 hydrocarbons
are 41.4 and 28.4 %, respectively, relative to the weight of tar supplied into the reactor.
Methane is the major component (40.5% mol.) of the volatile products; in LP oils
are prevailed (74.4% wt.). Deasphaltization and desulfurization of tar conversion
products are observed. The average rate of water decomposition calculated on the
basis of the O-atoms content in conversion products is 0.24 g/min. It is shown that the
combinations of counter flows of reagents with a temperature gradient along the reactor
axis provides with a higher yield of low-boiling products as compared to that obtained
at SCW pumping through the tar layer.

doi:

2016, №1

сс. 53-58

Articles

Key words: chlorophyll, carotenoids, supercritical fluid extraction, Fucus vesiculosus, Laminaria digitata, plant raw materials

The supercritical fluid extraction of chlorophyll and carotenoids from marine algae
Fucus Vesiculosus and Laminaria Digitata with carbon dioxide is studied. Carotenoids
can be completely extracted by pure CO2 during 20 min at 250 atm and 80 °C. To obtain
extracts with high content of chlorophylls, the addition of 10—15% vol. ethanol (polar
co-solvent), or prolonged extraction (50—90 min) at ethanol concentration < 5% vol.
are required.

doi:

2016, №1

сс. 59-71

Articles

Key words: supercritical carbon dioxide, pulse supersonic jet, van der Waals gas, isentropic expansion

Non-stationary isentropic expansion into the vacuum of the initially homogeneous
spherical cloud of van der Waals gas is considered as a dynamic part of the problem of
modeling the real gas pulse jet. A self-similar solution of gas dynamic equations is
obtained. The parameters of the pulse jet (density and temperature) that simulate the
conditions of a real experiment are calculated.

doi:

2016, №1

сс. 72-83

Articles

Key words: brown coal, coal-water slurry, supercritical water-oxygen fluid, combustion, gasification

The oxidation of brown coal continuously supplied as a coal-water slurry into a counter
flow of supercritical water-oxygen fluid at 30 MPa and the temperature difference in
the reactor along its axis (673—873 K) is studied. If a part of coal is burnt in the conditions
of O2 deficiency, the yield of products enriched with hydrogen is increased at the
expense of the producing heat of oxidation reactions. In excess of O2 the complete
oxidation of coal occurs; in this case the heat generation per unit volume of furnace
space about 1.0 MW/m3 is reached. It is shown that the heat expenditures from external
sources required to carry out the process can be partially or completely compensated
by the heat generated during homogeneous and heterogeneous combustion coupled
with the coal pyrolysis.

doi:

2016, №1

сс. 84-91

Articles

Sterilization of Ultra High Density Polyethylene in Subcritical Freons

D.Yu. Zalepugin, A.V. Maksimkin, M.V. Kiselevsky, N.A. Tilkunova, N.Yu. Anisimova, I.V. Chernyshova, F.S. Senatov, M.I. Vlasov.

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Key words: subcritical freons, sterilization, «press-depress» regime, ultra high density polyethylene

For the first time the ability of ultra high density polyethylene (UHDPE) sterilization
with subcritical freons R22 and R410a without any modificators is demonstrated. The
maximum sterilization effect is achieved when freon R410a is used in a static regime at
50 °C and 250 bar during 30 min and with freon R22 during 60 min at 70 °C at a cyclic
pressure variation between 100 and 290 bar («press-depress» mode).

doi:

2016, №2

сс. 4-13

Articles

Formation of Injection Form Components of Prolonged Action Acetilsalicylic Acid Using Supercritical Carbon Dioxide

E.N. Antonov, S.E. Bogorodski, L.I. Krotova, V.K. Popov, V.Yu. Belov, S.V. Kursakov, V.I. Sevastyanov.

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Key words: dosage forms of the prolonged action, polymeric microparticles, encapsulation of bioactive components, supercritical carbon dioxide, acetilsalicylic acid, kinetics of release, HPLC

The formation of fine-dispersed (10—100 μm) forms of bioresorbable ali phatic
polyesters containing acetilsalicylic acid (ASA) in therapeutic concentrations (up to
10 % wt.) from the supercritical carbon dioxide medium is studied. The procedure for
the production of the prolonged action injection forms of ASA is developed. The in
vitro kinetics of the ASA release from polylactide microparticles into the saline is
studied.

doi:

2016, №2

сс. 14-27

Articles

On the Role of Supercritical Water in Laser-Induced Backside Glass Wet Etching

M.Yu. Tsvetkov, V.I. Yusupov, P.S. Timashev, K.M. Golant, N.V. Minaev, S.I. Tsypina, V.N. Bagratashvili.

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Key words: laser-induced liquid etching, supercritical water, cavitation, microstructuring

The features and mechanisms of microcrater formation in optical silicate glass by
laser-induced backside wet etching (LIBWE) are determined in a wide range of energy
density (F) from 4 to 103 J/cm2 for laser pulses of 5 ns length and 1 kHz repetition rate.
The existence of two different mechanisms of laser-induced microcrater formation is
revealed: (i) chemical etching in supercritical water (SCW), and (ii) cavitation. At
Φ > 102 J/cm2 irregular craters of 1—20 microns in depth with rough walls and distinct
cracks around microcrater are formed testifying that in such mode («hard») laser
induced cavitation plays a dominant role in glass removal. At Φ < J/cm2 neat glass craters
with smooth walls are formed, their size and shape are well reproducible, cracks are not
formed, and processing area is limited to the laser spot area. In this mode («soft mode
with active cavitation»), a microcirculation of water is stimulated by cavitation without
causing undesirable shock breakage. The latter is achieved thanks to the fast removal of
glass etching products by microcirculation, and the inflow of «fresh» etchant (SCW) to
the glass surface in the vicinity of the formed microcraters. Such mode is optimal for
highly controlled laser microstructuring of glass and other optically transparent materials.

doi:

2016, №2

сс. 28-38

Articles

Key words: pyrite, pyrrhotite, supercritical water, hydrogen sulphide, sulfur

The interaction of pyrite (FeS2) with water at programmed heating (1.5 K/min) to
923 K and subsequent cooling (∼3 K/min) of the reactants to 423 K is studied. Reaction
products are analyzed by means of mass-spectrometry, scanning electron microscopy,
elemental and X-ray diffraction analyses. In the course of heating, H2S, SO2, rhombic
and hexagonal pyrrhotite (FeS) are formed. The subsequent cooling of the reaction
system results in the formation of monoclinic pyrrhotite with ferromagnetic properties,
cubic pyrite, H2S, and H2. It is shown that the FeS2 → FeS → FeSx
(1 < x ≤ 2) transformations are accompanied by changes in the morphology and the size of particles.

doi:

2016, №2

сс. 39-52

Articles

Treatment of Cotton Fabrics by Ammonium Palmitate in Supercritical CO2 Medium

A.A. Zakharov, Ameer Abed Jaddoa, T.R. Bilalov, F.M. Gumerov.

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Key words: ammonium palmitate, supercritical carbon dioxide, solubility, cotton fabric, impregnation, wetting angle, hydrophobicity

Experimental results on the solubility of ammonium palmitate as a potential fabric
water-repellent agent in supercritical carbon dioxide (SC-CO2) — pure and modified
with acetone and dimethyl sulfoxide — are presented. The measurements are performed
at temperatures 318.2 and 328.2 K in the pressure range from 10.0 to 32.5 MPa in a
dynamic regime. The experimental solubility data are described using the Peng —
Robinson equation of state. The results of treatment of various types of cotton fabrics
by ammonium palmitate in SC-CO2 are presented. The contact (wetting) angle of the
treated samples is determined and the increase in their hydrophobicity is demonstrated.

doi:

2016, №2

сс. 53-62

Articles

Supercritical Fluid Extraction as a Method of Thermochemical Activation of Wood Cell Walls

K.G. Bogolitsyn, M.A. Gusakova, A.A. Krasikova, A.D. Ivakhnov, S.S. Khviuzov, D.G. Chukhchin, I.N. Zubov.

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Key words: thermodynamic compatibility, cell wall, supercritical fluid extraction, lignin-carbohydrate matrix, wood substance, thermochemical activation

Thermochemical activation of lignocellulose matrix in the course of supercritical fluid
(SC) extraction is studied and changes of chemical composition and morphology of
the wood substance determined. A high heterogeneity of the wood substance structure
is demonstrated that is revealed in the presence of labile and stable regions of lignincarbohydrate
formations distributed in the cell wall and the middle lamellae. A new data
about chemical composition and morphological features of the wood substance and
its components can be obtained via the directed impact onto weak H-bonds of lignincarbohydrate
complex in the SC-CO2 medium.

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2016, №2

сс. 63-74

Articles

Biocompatibility and Degradation of Porous Matrixes from Lactide and ε-Caprolactone Copolymers Formed in Supercritical Carbon Dioxide Medium

P.S. Timashev, N.N. Vorobieva, A.A. Akovantseva, N.V. Minaev, Yu.A. Piskun, S.V. Kostjuk, I.I. Selezneva, I.V. Vasilenko, O.L. Zakharkina, N.Yu. Ignatieva, R.K. Chailakhyan, V.V. Lunin, V.N. Bagratashvili.

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Key words: porous materials, foaming, biodegradable polymers, degradation rate

Cytotoxicity and in vitro degradation rate of porous matrixes based on lactide and
ε-caprolactone copolymers formed via supercritical foaming are determined. A high
biocompatibility of materials obtained by the above method is demonstrated.

doi:

2016, №2

сс. 75-83

Articles

Supercritical Fluid Propane-Butane Extraction Treament of Oil Sludge

F.M. Gumerov, V.F. Khairutdinov, T.R. Akhmetzyanov, F.R. Gabitov, Z.I. Zaripov, M.I. Farakhov, A.V. Mukhutdinov.

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Key words: extraction, propane, butane, oil sludge, supercritical fluid, kinetics

The extraction by the mixture of propane and butane (3 : 1 by weight) in liquid and
supercritical fluid state at 85—160 °C and 5—50 MPa is used to obtain an oil-like product
from dehydrated oil sludge containing 12.05% wt. of solid particulates. The extracted
product contains 2.8% wt. sulfur; at 20 °C its kinematic viscosity is 73.75 mm2/s,
density — 80 kg/m3; the initial and final boiling temperatures are 43.6 and 325 °C,
respectively. The data on the kinetics of the extractant desorption from the extract are
presented.

doi:

2016, №2

сс. 84-85

Information

2016, №3

сс. 3-9

Articles

Key words: inactivation, Escherichia coli, supercritical gases, CO2, O2, N2

The kinetics of inactivation of Escherichia coli under the action of pressurized gases
(CO2, O2 and N2) is studied. It is demonstrated that the concentration of survived cells
decreases by 7 orders in the case of CO2 and less than by one order in the case of O2
and N2. An assumption about the major mechanism of bacterial cells inactivation in
the presence of CO2 is proposed.

doi:

2016, №3

сс. 10-16

Articles

Catalytic Hydrogenation of Nitrobenzene in Supercritical Carbon Dioxide Using Ruthenium Catalyst

M.Yu. Rakitin, V.Yu. Doluda, A.A. Tyanina, A.I. Petrova, E.M. Sulman, V.G. Matveeva.

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Key words: nitrobenzene, aniline, supercritical carbon dioxide, hydrogenation, ruthenium, hypercrosslinked polystyrene

Catalytic hydrogenation of nitrobenzene in isopropanol and supercritical (SC) carbon
dioxide media using ruthenium catalysts supported on hypercrosslinked polystyrene is
studied. Both reaction rate and selectivity to aniline are higher in SC-CO2.

doi:

2016, №3

сс. 17-33

Articles

The Role of Supercritical Water and Pyrite in the Transformations of Propylene

O.N. Fedyaeva, A.A. Vostrikov, V.R. Antipenko, A.V. Shishkin, V.I. Kolobov, M.Ya. Sokol.

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Key words: propylene, supercritical water, pyrite, oligomerization, sulfidation, synergetic effect

The effect of supercritical water and pyrite on the transformations of propylene at
programmed heating (1.5 K/min) of the reagents to 718 K is studied. The products are
analyzed by IR and 1H NMR spectroscopy, mass-spectrometry and gas chromatography/mass-spectrometry.
Based on the temperature dependences of pressure of the reagents
it is stated that in the absence of water, the addition of pyrite reduces the initial
temperature of propylene oligomerization. In the absence of pyrite, the addition of
water suppresses the propylene oligomerization. A synergetic effect of supercritical
water and pyrite on the degree of propylene conversion is revealed. It is shown that in
the presence of pyrite, hydrogen sulfide, thiols and methyl-derivatives of thiophene are
formed and the yield of aromatic and polyaromatic hydrocarbons is increased. The
mechanisms of the observed processes are discussed.

doi: