Key words: импрегнация, СВМПЭ, амоксициллин, субкритический фреон R22
Because of investigation the method of impregnation of ultra high density polyethylene
(UHDPE) with amoxicillin in subcritical freon R22 was developed. For the first time
a possibility of polymer, impregnation with polar substance in the absence of modifier
was demonstrated. Usually removal of modifiers from polymer matrix is a serious problem.
Amoxicillin desorption curves (drug release) were calculated using HPLC method.
Polymer samples impregnated with amoxicillin manifested antibacterial activities in
relation to gram-positive and gram-negative microorganisms <i>S. aureus</i>, <i>S. epidermidis</i>,
<i>E. faecalis</i>, <i>B. subtilis</i>, <i>E. coli</i>, that provides a perspective for using them as real models of
implants for bone replacement.
Key words: синтез в сверхкритических условиях, ацетилацетон, смешанные Ce-Zr оксиды, углекислотная конверсия метана
The paper considers the effect of zirconium starting compounds on the properties of
mixed Ce-Zr oxides synthesized by solvothermal method in a flow reactor using ethanol
and isopropanol as a supercritical media. Phase composition and structural properties
of synthesized samples were investigated by X-ray diffraction and Raman spectroscopy.
The morphology and textural properties were studied by transmission electron
microscopy and thermal desorption of nitrogen. If zirconium oxychloride or acetate
are used, the formation of mixtures of phases enriched in cerium or zirconium is
observed, whereas in the case of zirconium butoxide added with a complexing agent
(acetylacetone) a homogeneous solid solution is formed. The comparison of catalytic
properties of synthesized oxides with supported Ni in the reaction of methane dry
reforming demonstrated that the catalyst based on the single-phase mixed ceria-zirconia
oxide is significantly more active, selective and stable to coking.
Key words: пропиконазол, сверхкритический СО<sub>2</sub>, растворимость, древесина, сушка, импрегнация
Drying of wood in the supercritical (SC) CO<sub>2</sub> and SC-CO<sub>2</sub> added with ethanol (5%)
media at 323, 343 and 353 K and 10, 20 and 30 MPa is studied. During the first drying
cycle 40—87% of the initial moisture can be removed from the material. The number
of cracks in the wood can be reduced by prolongation of the decompression stage of
the drying process. Solubility of propiconazole in SC-CO<sub>2</sub> is studied using a dynamic
method. Its high saturation concentrations — (3—5)⋅10<sup>-3</sup> mole per mole of СО<sub>2</sub> —
indicate that potentially SC-CO<sub>2</sub> can be considered as a candidate solvent for
impregnation of wood with propiconazole. It is demonstrated that through impregnation
of wood samples can be achieved, and the efficiency of impregnation increases at
increased duration of the process.
Key words: сверхкритическая флюидная экстракция, вторичные лишайниковые метаболиты, усниновая кислота, лишайник рода <i>Cladonia</i>, параметры процесса экстракции
The process of supercritical fluid extraction (SFE) of secondary metabolites from
<i>Cladonia</i> genus lichen with carbon dioxide is studied. The solid extract yield obtained
via carbon dioxide extraction exceeds by far that obtained via acetone extraction in a
Soxhlet apparatus. The maximum content of the target component — usnic acid — in
the extract (91 %, yield — 2.5% of absolutely dry material) is obtained at 35 MPa, 40 °C
and the SFE process duration 40 minutes. The product yield can be increased to 3% by
the addition of co-solvents (acetone, ethanol, methylene chloride) to carbon dioxide.
Key words: парацетамол, сверхкритический CO<sub>2</sub>, фазовое равновесие, растворимость, теплоемкость, диспергирование по методу SEDS
Solubility of paracetamol in supercritical carbon dioxide and its mixtures with acetone
is experimentally studied. Isobaric heat capacities of paracetamol and «paracetamol —
SC—CO<sub>2</sub>», «paracetamol — acetone — SC—CO<sub>2</sub>» systems at 303—523 K and 7—29 MPa
are measured. The results of paracetamol dispersing using the SEDS (Solution Enhanced
Dispersion by Supercritical Fluids) method are presented.
Key words: тройные водно-солевые системы, сверхкритические фазовые равновесия, диаграммы состояния
Supercritical phase equilibria in ternary system K<sub>2</sub>SO<sub>4</sub>—KOH—H<sub>2</sub>O at 420—500 °C
and up to 130 MPa pressure with binary boundary subsystems of different types are
studied. The binary subsystem of type 1 do not have any critical phenomena in saturated
(l = g — s) aqueous solution as well as the immiscibility equilibrium (l<sub>1</sub>—l<sub>2</sub>) (КОН—Н<sub>2</sub>O),
the second binary subsystem of type 2 (K<sub>2</sub>SO<sub>4</sub>—H<sub>2</sub>O) has two critical end-points
<b>p</b> (g = l — s<sub>K<sub>2</sub>SO<sub>4</sub></sub>) and <b>Q</b> (l<sub>1</sub> = l<sub>2</sub>—s<sub>K<sub>2</sub>SO<sub>4</sub></sub>)
with saturated aqueous solution and the liquid-liquid
immiscibility equilibria. The ternary system has two three-phase equilibria
(g — l — s<sub>K<sub>2</sub>SO<sub>4</sub></sub>) and (l<sub>1</sub> — l<sub>2</sub> — s<sub>Na<sub>2</sub>SO<sub>4</sub></sub>),
separated by a two-phase supercritical fluid region
(fl—s<sub>K<sub>2</sub>SO<sub>4</sub></sub>) and two types of monovariant critical curves
(g = l — s<sub>K<sub>2</sub>SO<sub>4</sub></sub>) and (l<sub>1</sub> = l<sub>2</sub> — s<sub>K<sub>2</sub>SO<sub>4</sub></sub>).
The three?phase regions approach each other at temperature increased up to the
point where the two-phase supercritical equilibrium disappeares, and the two mentioned
monovariant critical curves are joined into a double homogeneous critical point
(g = l — s ↔ l<sub>1</sub> = l<sub>2</sub> — s)
at maximum temperature ∼ 445 °C and 51—52 MPa.
Key words: горючий сланец, сверхкритическая вода, отношение четные/нечетные, алканы, алкены, полиароматические углеводороды, бензо- и дибензотиофены
The composition of oily fractions (OFs) formed by the Kashpir oil shale conversion
in a flow of water vapor and supercritical water under uniform heating from 300 to
550 °C is studied by means of gas-chromatography/mass-spectrometry, IR and <sup>1</sup>H NMR
spectroscopy. A maximum yield of oil fraction is observed at 360–390 °C. Alkanes, alkenes,
alkyl-derivatives of naphthalene and benzothiophene are the major components of
OFs formed below 440 °C. A significant predominance of even alkanes and alkenes
over their odd homologies is detected above 440 °C. The peculiarities in the varying
of the content of specific groups and individual polyaromatic substances are discussed.
Key words: горючие сланцы, сверхкритическая флюидная экстракция, пиролизаты, компоненты, структура, состав
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 <sup>1</sup>H 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.
Key words: субкритическая вода, апорфиновые алкалоиды, глауцин, фенантреновые алкалоиды, секо-глауцин, высокоэффективная жидкостная хроматография
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.
Key words: герань душистая, эфирное масло, сверхкритическая флюидная экстракция
Optimal conditions (40 °C, 16 MPa, process duration 30 min) for the extraction of
<i>Pelargonium graveolens</i> 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-CO<sub>2</sub>.
Key words: сверхкритические флюиды, аэрогель, сверхкритическая сушка, гомогенизация, распыление
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.
Key words: полимерные мембраны, газоразделение, 1,2-дизамещенные полиацетилены, химическая модификация полимеров, выделение СО<sub>2</sub>, проницаемость, селективность, кватернизация
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 CO<sub>2</sub>-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 CO<sub>2</sub>/N<sub>2</sub> selectivity in comparison with initial
poly(4-methyl-2-pentyne).
Key words: остеопластический матрикс, костный блок, сверхкритический диоксид углерода, делипидизация, кость, имплантаты
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 <sub>in vitro</sub> experiments are demonstrated.
Key words: сапфир, лазерное жидкостное травление, микроструктурирование, термоплазмоника, сверхкритическая вода, ультравысокие давления и температуры
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 AgNO<sub>3</sub>, 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 Al<sub>2</sub>O<sub>3</sub> as a result of TPLIBWE.
Key words: тяжелая нефть, сверхкритический водокислородный флюид, активированный уголь, окисление, тепловыделение
The composition of oily fractions (OFs) obtained at the heavy sulfur-rich oil conversion
is studied by means of physical and chemical methods of analysis. The oil was supplied
from the top into the vertical tubular reactor packed with activated carbon (AC),
where supercritical water-oxygen fluid was pumped from the bottom through the AC
bed. The experiment was performed at 30 MPa, temperature of upper, middle and
bottom parts of the reactor equal to 673, 723 and 723 K, variable flow rate of oxygen
(0—3.5 g/min) and constant flow rate of oil and water (4 and 6 g/min, respectively).
Based on the temporal trends in the reactor wall temperature and the power of
resistance heaters it is revealed that due to heat generation during the combustion of
oil high-molecular components, accumulated in the AC bed, the conversion process
occurs in autothermal mode. The movement of the combustion front along the reactor
axis is detected. It is shown that isoprenoids and normal alkanes, 1-alkyl-2,3,6-
trimethylbenzenes, alkyl-derivatives of benzo- and dibenzothiophenes are the main
components of the crude oil OF. The yield of OFs, whose portion in the liquid products
exceeds 90 %, has an extreme dependence on the oxygen flow rate. As the latter increases
and the temperature of the reaction mixture rises due to a heat generation upon
combustion, the relative content of bi- and tricyclic aromatic hydrocarbons alkylderivatives,
as well as benzo- and dibenzothiophenes in the OFs of conversion products
increases too. The content of fractions boiling at T < 493 K in the OFs of the conversion
product increases by 2—3 times compared to the crude oil OF.
Key words: пленочный композит, селенид кадмия, нанокристаллический кремний, диффузионное внедрение, люминесцентные свойства, волокнистая матрица
A method to produce film composites based on the tetrafluoroethylene-vinylidene
fluoride fiber copolymer using diffusion implantation of nanoparticles dispersed in a
supercritical (SC) carbon dioxide CO<sub>2</sub> medium has been developed. At the final stage
of the formation of such materials, a cold or hot pressing of impregnated porous films
is applied. The effect of treatment in SC-CO<sub>2</sub> on the surface structure of pressed films
is discussed. The materials containing nanoparticles of semiconductors (cadmium
selenide and nanocrystalline silicon) whose radiation covers a range of 500—1000 nm
are obtained. Their luminescent characteristics under the laser excitation (irradiation
wavelength 405 nm) are presented.
Key words: аэросиликагель, адсорбция диоксида углерода, аминофункционализация
Mesoporous silica gel samples, including those functionalized with amino groups, were
prepared using sol-gel synthesis followed by drying in supercritical carbon dioxide.
Relationshi ps between the conditions of preparation and modification of the silica
sample and their textural and adsorptive properties are established. The obtained porous
materials are considered as promising adsorbents for the recovery of carbon dioxide
from gas media.
Key words: полимеры, пористость, сверхкритические флюиды, субкритические фреоны, диоксид углерода
For the first time the treatment of polystyrene in sub- and supercritical freon media
in comparison with supercritical carbon dioxide was studied. Subcritical freon R22
can more efficiently saturate polystyrene than subcritical freon R410а and supercritical
freon R23 and carbon dioxide. The subsequent heating of polystyrene samples saturated
with R22 freon leads to the formation of the polymer with connected porous structure
and average pore size up to 250 μm. The results obtained can be used in the development
of technologies for porous polystyrene production.
Key words: сверхкритические флюиды, микронизация, полимеризация, полимерные микрочастицы, функциональные порошковые покрытия, развитие рынка
This review analyzes the studies and developments of technologies based on the use of
supercritical fluids for micronization of polymer particles and formation of efficient
powder polymer coatings. Potential advantages of supercritical fluid technologies that
combine different stages of powder coating formation in a unified flowsheet are
considered. Possible further trends in the scientific and engineering research are
identified. The growth of powder coatings global market in perspective to the year
2020 is forecasted.
Key words: структурированные гидрогели, матриксы, лазерная стереолитография, сверхкритические флюиды
Hydrogel matrix structures (matrixes) based on the allyl-substituted chitosan derivatives
are formed using the laser stereolithography. The effects of their processing in the
supercritical carbon dioxide (SC-CO<sub>2</sub>) onto the surface polarity and mechanical
characteristics are studied. It is found that such treatment of matrixes in the flow
regime increases the mechanical strength due to an efficient extraction of low molecular
weight components and oligomers from the material. In addition, the processing in the
SC-CO<sub>2</sub> decreases the surface polarity and, as a result, improves the biocompatibility of
the material. The hydrogel matrixes treated in the SC-CO<sub>2</sub> have no cytotoxic effect and
are prospective materials for tissue engineering.