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2019, №1

сс. 6-10

IN MEMORIAM

Victor Bagratashvili and the Renaissance of Supercritical Fluid Research in Russia

Martyn Poliakoff.

2019, №1

сс. 11-13

IN MEMORIAM

Comet «Burned» in the Day of Cosmonautics (Memories of Victor N. Bagratashvili)

O.O. Parenago.

2019, №1

сс. 14-31

Articles

Quas-Adiabatic Expansion of the Polylactide Foam: Features of the Porous Matrices Formation in the Region of Transition Between Sub- and Supercritical States of Plasticizing Carbon Dioxide

D.A. Zimnyakov, V.N. Bagratashvili, S.A. Yuvchenko, I.O. Slavnetskov, A.V. Kalacheva, O.V. Ushakova.

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Abstract

Key words: adiabatic expansion, foam, polylactide, carbon dioxide, equation of state, low-coherence reflectometry

Experimental data on the dynamics of quasi-adiabatic expansion of the foam, which is
formed on the base of carbon-dioxide-plasticized polylactide in the course of fast
depressurization, are presented. It is shown that, in the range of initial pressure, which
corresponds to the region of transition between the subcritical and supercritical states of
plasticizing agent, the substantial increase in the resulting volume of the formed porous
matrices takes place. Study of the structure of synthesized matrices at the mesoscopic level
provided using the low-coherence reflectometry showed the dramatic difference in
comparison with the synthesis conditions far from the transition region. The observed
features are interpreted in the framework of a qualitative model based on the equation of
foam state proposed by Ross. The considered model takes into account the sign of increment
of the internal energy of a plasticizing and foaming agent in the course of transition
between the initial and final thermodynamics states of the foamed polymer.

doi:10.34984/SCFTP.2019.14.1.003

2019, №1

сс. 32-46

Articles

Effect of Water in the Process of Chitosan Impregnation in SC-CO2 by Hydrophobic Diarylimidazoles and in the Kinetics of their Subsequent Release in the Model Biological Medium

V.N. Bagratashvili, A.V. Cherkasova, N.N. Glagolev, A.I. Shienok, V.A. Timofeeva, A.B. Solovieva.

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Abstract

Key words: supercriticalcarbondioxide, biodegradablepolymers, substituteddiarylimidazoles, compositions with a slow release of the active substance, solubilization.

Compositions based on chitosan and substituted diarylimidazoles (DAI), which have
an antitumor effect, with a slow release of active substances have been obtained in the
SC-CO2 medium. It has been established that the use of water (0.17% by volume) as
a co-solvent during SCF-impregnation of chitosan with diarylimidazoles leads to an
increase in the content of DAI in the polymer matrices. Obviously, it is due to an
increase in the degree of chitosan swelling in the SC-CO2 medium in the presence of water.

It is interesting to note that the effect of water on the release rateof diarylimidazoles
from the polymer matrices into the model medium with pH 1.6 was determined by
the structure of diarylimidazoles. For the first time it has been shown that the
solubilization of DAI molecules by Pluronic F-127 before their SC-introduction into
the matrices of chitosan can be used as an additional effective method of prolonging
the action of matrix preparations.

doi:10.34984/SCFTP.2019.14.1.004

2019, №1

сс. 47-66

Articles

Laser Formation of Nanoparticles and Plasmon Structures in Porous Materials Using SCF-Technologies

A.O. Rybaltovskii, V.G. Arakcheev, N.V. Minaev, V.I. Yusupov, S.I. Tsypina.

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Abstract

Key words: supercritical fluid, nanoparticles, polymers, porous glasses, structures, selfassembly, carbon dioxide, laser formation

It was presented the review of our research on the processes of metal nanoparticles
formation (silver and gold), as well as various types of structures of them in polymeric
and porous materials, which are based on the effects of self-assembly and selforganization
in the field of continuous laser radiation. Most of the experiments were
carried out either on samples impregnated with metal precursors in a supercritical
carbon dioxide (SC-CO2) medium or at the time they were in that medium. Various
types of metal nanoparticles structures in polymers and porous glasses were synthesized:
periodic structures of micron and submillimeter scales, layered structures of nanoparticles
with an unusually small period (about 90 nm), filamentous, ring structures
and islet films of nanoparticles. Some regularities and mechanisms of formation of
nanoparticles and their structures depending on the wavelength of laser radiation are
established. In addition, new original results are presented on the method of obtaining
of composite porous foam-like materials based on silver nanoparticles and polymer
matrices, which combines laser-induced «drawing» of porous structures, their
impregnation by precursor molecules using SCF technologies and subsequent recovery
of nanoparticles.

doi:10.34984/SCFTP.2019.14.1.005

2019, №1

сс. 67-70

Articles

Release Kinetics of the Nitroxyl Radicaltempone from D,L-Polylactide Foamed in the Environment of Supercritical Carbon Dioxide

T.A. Ivanova, N.A. Chumakova, E.N. Golubeva, V.V. Lunin.

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Abstract

Key words: supercritical carbon dioxide, electron paramagnetic resonance spectroscopy, polylactide, spin probe

For the first time, the EPR-method was used to quantitatively describe the process of
releasing a paramagnetic biologically active substance from a polymer biodegradable
matrix. A standard TEMPONE spin probe was chosen as the paramagnetic compound,
and D, L-polylactide foamed in supercritical carbon dioxide was used as the polymer.
It is shown that the release of TEMPONE from porous D, L-polylactide into phosphate
buffer with pH 7,4 occurs gradually, without periods of burst and stagnation, which
indicates that it is possible in principle to use the used technology of impregnation
and foaming of the polymer to create materials for medicalpurposes.

doi:10.34984/SCFTP.2019.14.1.006

2019, №1

сс. 71-88

Articles

Laser-Induced Formation of Supercritical Water

V.I. Yusupov.

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Abstract

Key words: supercritical water, laser-induced production, spectroscopy, laser technology, mechanism of SCW formation

The paper presents a review of publications that describe the laser-induced formation
of supercritical water (SCW) and discusses methods for monitoring these fast
processes. The formation of SCW can occur as a result of both pulsed and continuous
laser irradiation. The primary act in this process is the absorption of laser energy with
the transition to heat and/or pressure impulse. Such absorption can occur in pure
water, in some targets or in various absorbers in water, for example, metal or carbon
nanoparticles. It is shown that laser methods are effective for forming SCW, and its
contribution to the mechanism of action under various laser technologies should be
taken into account, since its influence on the processes taking place is often prevalent.

doi:10.34984/SCFTP.2019.14.1.007

2019, №1

сс. 89-93

Articles

Molecular Refraction and Nonlinear Refractive Index of Supercritical Carbon Dioxide under Clustering Conditions

E.I. Mareev, V.A. Aleshkevich, F.V. Potemkin, N.V. Minaev, V.M. Gordienko.

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Abstract

Key words: nonlinear refractive index, molecular refraction, Lorentz—Lorentz function, molecular dynamics, nonlinear optiсs, Widom line

A model of clustered binary medium is proposed. It describes the anomalous behavior
of the linear (Lorentz—Lorentz function) and the nonlinear (nonlinear refractive
index) optical properties of supercritical CO2. Using computer simulation based on
the molecular dynamics, we verified the validity of this model, that describes the
anomalous behavior of the nonlinear refractive index of supercritical CO2 in the
vicinity of the Widom line, due to clustering.

doi:10.34984/SCFTP.2019.14.1.008

2019, №1

сс. 94-107

Articles

Single-Stage Formation of Film Polymer Composites in the Environment of Supercretical Colloidal Solutions of Nanoparticles Obtained by Laser Ablation

S.I. Tsypina, E.O. Epifanov, A.G. Shubny, V.G. Arakcheev, N.V. Minaev, A.O. Rybaltovskii.

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Abstract

Key words: supercritical carbon dioxide, nanocolloid, bimetallic nanoparticles, porous polymers, film nanocomposites

We present a review of previous studies, as well as new results on the creation of highly
concentrated colloidal solutions with nanoparticles of noble metals (gold and silver)
in the medium of supercritical carbon dioxide and the development of a single-stage
method for the production of polymer nanocomposites. The effect of the density of
supercritical carbon dioxide on the dynamics of the formation and decomposition of
supercritical fluids of silver and gold nanocolloids in the process of pulsed laser
ablation and after its termination has been studied. The possibility of obtaining colloids
of bimetallic nanoparticles is considered. Using the method of numerical simulation of
the extinction spectra in the dipole approximation, we calculated the effective dielectric
constant of a colloidal solution of Ag nanoparticles in supercritical CO2 at various
densities, taking into account the size and degree of asphericity of the nanoparticles.
The processes of formation in one SCF reactor and in a single technological process of
various film nanocomposites are considered: based on a porous polytetrafluoroethylene
copolymer - vinylidene fluoride with ruby glass nanoparticles and on the basis of two
modifications of pure porous polytetrafluoroethylene with silver nanoparticles.

doi:10.34984/SCFTP.2019.14.1.009

2019, №2

сс. 4-13

Articles

Development of Polymer Waste Impregnation Method in Subcritical Freon R22 Media with Substances Promoting their Biodegradation in Nature

D.Yu. Zalepugin, V.A. Karpov, N.A. Tilkunova, Yu.L. Kovalchuk, I.V. Chernyshova, T.A. Semenova.

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Abstract

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

2019, №2

сс. 14-22

Articles

«One-pot»-Technique for Production of Oleanolic Acid from the Roots of Aralia mandshurica by Subcritical Water

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

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Abstract

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

2019, №2

сс. 23-30

Articles

Conjugated Processes of Heterogeneous-Homogeneous Oxidation of Hydrogen in High-Density H2/O2/H2O, H2/O2/CO2 and H2/O2/N2 Mixtures

A.A. Vostrikov, O.N. Fedyaeva, A.V. Shishkin, M.Ya. Sokol.

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Abstract

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

2019, №2

сс. 31-39

Articles

Cyclization of o-phenylenediamine and o-substituted Anilines with Carbon Dioxide in Supercritical State

Yu.M. Panov, L.V. Erkhova, A.G. Balybin, D.P. Krut'ko, D.A. Lemenovskii.

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Abstract

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

2019, №2

сс. 40-66

Articles

Description of Solubility in Supercritical Carbon Dioxide as a Method to Determine Saturated Vapor Pressure of Desolved Substances

T.R. Bilalov, F.M. Gumerov.

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Abstract

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

2019, №2

сс. 67-72

Articles

Solubility of malonic and succinic acids in CO2-solvent mixtures and micronization via supercritical antisolvent precipitation

A.D. Ivakhnov, T.E. Skrebets.

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Abstract

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

2019, №2

сс. 73-104

Articles

Critical and Supercritical Phenomena in Benzene

N.G. Polikhronidi, R.G. Batyrova, I.M. Abdulagatov.

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Abstract

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.

2019, №2

сс. 105-115

Articles

Formation of Dispersed Particles of Tungsten Oxide and Deposition of Platinum Nanoparticles on Them Using Organometallic Precursors From Solutions in Supercritical Carbon Dioxide

A.Yu. Nikolaev, V.E. Sizov, S.S. Abramchuk, M.O. Gallyamov.

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Abstract

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

2019, №2

сс. 116-134

Articles

Some Methodological Aspects of the Study of Chemical Processes in Water Fluid Media

M.Yu. Sinev, Yu.A. Gordienko, E.A. Ponomareva, Yu.D. Ivakin.

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Abstract

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

2019, №3

сс. 4-10

Current Events

The 10th Scientific and Engineering Conference with International Participation
«Supercritical Fluids: Fundamentals, Technologies, Innovations»,
Rostov-on-Don, September 30—October 6, 2019

2019, №3

сс. 11-25

Reviews

Impregnation of Polymer Materials in Supercritical Media

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

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Abstract

Key words: polymer, impregnation, supercritical fluids, carbon dioxide

The review summarizes the achievements in the field of polymer impregnation during
latest years. In particular, new methods of impregnation process and application of
some new fluids are demonstrated. Concrete examples and conditions of impregnation
processes and new areas of method applications are discussed.

doi:10.34984/SCFTP.2019.14.3.002

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