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Vol 99, No 8 (2025)
- Year: 2025
- Published: 15.08.2025
- Articles: 20
- URL: https://bakhtiniada.ru/0044-4537/issue/view/23765
CHALLENGES, DEVELOPMENT TRENDS, AND CURRENT PROBLEMS OF PHYSICAL CHEMISTRY
Casimir polarization of the electromagnetic field vacuum in the vicinity of particles as a determinant of their interactions: phenomenology
Abstract
It is shown that the introduction of non-zero volume of particles, as well as the notion of kasimirov polarization of electromagnetic field vacuum – EM-vacuum in the vicinity of atoms, atomic nuclei and elementary particles with formation of corresponding EM-polarons, allows to understand the physical essence of quantum phenomena and processes determined by “overlapping” (interaction) of kasimirov polarization regions in the vicinity of particles. The physical essence of the effect of “entanglement” (“entanglement”) is discussed; the variety of processes of Bose-Einstein condensation of particles and formed condensates, the genesis of inertia forces arising in accordance with the 3rd law of Newton’s mechanics at all levels of spatial and temporal organization of the universe; the key role of virtual photons in all the above processes. It is shown that within the framework of the previously proposed model of the dynamics of the universe as an integral open system the connections establishing the nature of irreversibility of the dynamics of all processes, up to the processes of energy transmission to electron subsystems of atoms and nuclear matter of nuclei, which is necessary for stabilization of functional activity of these systems, can be revealed. In particular, within the framework of the presented understanding of the physical essence of the phenomena of superconductivity and superfluidity, one of the key epistemological problems is solved – understanding of the physical basis of the manifestations of “nondissipativity” of these phenomena.
Russian Journal of Physical Chemistry. 2025;99(8):1125-1138
1125-1138
CHEMICAL THERMODYNAMICS AND THERMOCHEMISTRY
Thermodynamics of irreversible processes in an isothermal catalyst grain
Abstract
Numerical analysis of local and total entropy production in the simplest linear and nonlinear reaction-diffusion systems depending on boundary conditions and initial conditions has been carried out. It is shown that the results of calculations for linear and nonlinear differential equations at large values of the equilibrium constant do not differ practically. It is found that the total entropy production in the system is not a functional of the solution of the problem possessing extreme properties. As a selective potential possessing extreme properties, one can use the entropy production in the system only due to one of the irreversible processes – diffusion or reaction.
Russian Journal of Physical Chemistry. 2025;99(8):1139-1146
1139-1146
Thermodynamics of stepwise dissociation glycyl-l-aspartic acid and glycyl-l-glutamic acid
Abstract
Thermal effects of protolytic equilibria of glycyl-L-aspartic and glycyl-L-glutamic acids at 298.15 K and ionic strength values of 0.1, 0.3, 0.5, 1.0, 1.5 (KNO3) were determined by direct calorimetric method. Using the results of thermochemical and potentiometric research carried out under identical experimental conditions, the standard thermodynamic characteristics (pK°, ∆disG°, ∆disH°, ∆disS°) of the stepwise dissociation reactions of these dipeptides were calculated. The results obtained were compared with the corresponding data on related compounds.
Russian Journal of Physical Chemistry. 2025;99(8):1147-1153
1147-1153
Heat Capacity and Thermodynamic Properties of Mometasone Furoate
Abstract
The temperature dependence of the heat capacity of mometasone furoate in the range from 6 to 500 K was determined by adiabatic vacuum calorimetry and differential scanning calorimetry for the first time. Standard thermodynamic functions of crystalline mometasone furoate were determined: heat capacity Cp°(T), enthalpy [H°(T) – H°(0)], enthalpy S°(T) Gibbs function [G°(T) – H°(0)] for the temperature range from T → 0 to 490 K. A regularity between the Debye temperature and the composition of steroid hormones was revealed.
Russian Journal of Physical Chemistry. 2025;99(8):1154-1162
1154-1162
HEAT CAPACITY AND THERMODYNAMIC PROPERTIES OF LA3TAO7
Abstract
By relaxation, adiabatic and differential scanning calorimetry methods the molar heat capacity of lanthanum tantalate La3TaO7 of the structural type of weberite has been measured in the temperature range 0–1760 K and the thermodynamic properties have been calculated from the smoothed values of heat capacity: entropy and enthalpy increment, the Gibbs energy of lanthanum tantalate formation from binary oxides in the region of high temperatures was estimated and high stability of La3TaO7 was shown.
Russian Journal of Physical Chemistry. 2025;99(8):1163-1169
1163-1169
CHEMICAL KINETICS AND CATALYSIS
Evolution of Macroscopic Properties of the System During Sol-Gel Synthesis of Lead Zirconate Titanate Ceramics Precursor
Abstract
The influence of the amount of hydrolyzing agent on the kinetics of hydrolysis of lead zirconate-titanate precursor solution is considered from the point of view of the rate of change of hydrodynamic diameters of primary particles of the sol formed at the first stage, evolution of particle size distributions, rheological and optical properties of the colloidal systems. It is shown that changing the ratio of hydrolyzing agent: organometallic compounds is an effective controlling factor at the early stage of sol-gel-synthesis of piezoceramics of lead zirconate-titanate system and allows to obtain gel with controlled speed and necessary particle sizes.
Russian Journal of Physical Chemistry. 2025;99(8):1170-1178
1170-1178
PHYSICAL CHEMISTRY OF SOLUTIONS
The Effect of Acidity of the Medium on the Structure Nile Red
Abstract
The change in the structure of Nile red when treated with acids of different strength: acetic, formic and hydrochloric acids was studied by IR spectroscopy. In the IR spectra of the dye dried after treatment with formic and hydrochloric acids, the appearance of absorption spectra corresponding to shaft vibrations of N–H+-bonds of tertiary amines and O–H-bonds of hydroxyl groups was recorded. In the IR spectra of the dye dissolved in acetic and formic acids, the appearance of the absorption spectra of O–H-bonds of hydroxyl groups is predominantly traced. Thus, it was found that the most probably protonation centers in the molecule of Nile red are the amino group and carbonyl group. Analysis of UV-visible spectra of the dye in acetic and formic acid and in DMSO showed that in acetic acid Nile red probably exists mainly in the non-protonated form, and in stronger formic acid a significant part of its molecules is protonated, which is accompanied by a complication of the form of the spectrum.
Russian Journal of Physical Chemistry. 2025;99(8):1179-1190
1179-1190
Physicochemical properties of lithium perchlorate solutions in mixtures of sulfolane with alkyl acetates
Abstract
The physicochemical properties of 1.0 M solutions of lithium perchlorate in mixtures of sulfolane with methyl-, ethyl-, and butyl acetate have been studied and it has been found that the introduction of alkyl acetates leads to a decrease in the toughness of electrolyte solutions and an expansion of the temperature range of the liquid-phase state. The isotherms (30°C) of the specific ion conductivity of 1.0 M solutions of lithium perchlorate in sulfolane-alkyl acetate mixtures show maxima, the position of which is determined by the molecular weight of alkyl acetate. The electrochemical stability window of 1.0 M solutions of LiClO4 in sulfolane-alkyl acetate mixtures is 5.7–5.8 V vs. Li/Li+.
Russian Journal of Physical Chemistry. 2025;99(8):1191-1197
1191-1197
On the transition temperature of liquid supercooled aqueous solution into ferroelectric state
Abstract
The temperature of the ferroelectric transition of a liquid solution of a polar substance in water is calculated. An experiment is proposed to test the assumption about the ferroelectric nature of the known anomalous properties of water.
Russian Journal of Physical Chemistry. 2025;99(8):1198-1200
1198-1200
PHYSICAL CHEMISTRY OF NANOCLUSTERS, SUPRAMOLECULAR STRUCTURES, AND NANOMATERIALS
Hydrate Formation in Gas-Saturated Layers of Amorphous Ice with Crystalline Nuclei
Abstract
The formation of propane hydrate in gas-saturated condensates of amorphous ice in the presence of nucleated crystals has been studied. Amorphous gas-saturated layers were obtained by condensation of supersonic flows of rarefied vapor and gas on a liquid nitrogen cooled substrate. Samples were prepared using both parallel flows with orientation normal to the substrate and at an angle to it towards each other. The formation of ice nanocrystals during adiabatic expansion of the vapor flow at the supersonic nozzle exit ensured their presence in the condensates. Changes in the specific surface density (porosity) of amorphous gas-saturated condensates at changing the orientation of flows with respect to the substrate and the presence of nucleated crystals in nonequilibrium condensates affect their stability and crystallization kinetics. Under conditions of deep metastability, a spontaneous crystallization mode with the capture of adsorbed gas molecules and the formation of gas hydrate is realized. The crystallized condensates contained high gas content exceeding its value for hydrate in the equilibrium state. Excessive gas content indicates the presence of gas in the intergranular space and porous medium of the sample.
Russian Journal of Physical Chemistry. 2025;99(8):1201-1206
1201-1206
Effect of nanoparticle stabilization of suspension of micro-sized particles of doped cerium dioxide for electrophoresis
Abstract
The results of research on zeta potential, pH and electrophoretic precipitation characteristics (EPO) of Ce0.8Sm0.2O1.9 (SDC-m) microsize powder suspensions upon addition of different fraction of SDC-n nanoparticles are presented. The effect of stabilization of the suspension of microsized particles due to the introduction of highly charged nanoparticles is shown. The non-monotonic character of the coating thickness change at EFO from SDC-m/SDC-n suspension with the increase of SDC-n nanoparticles content with the tendency of zeta-potential and resistance of the suspension to increase has been established. It is shown that the greatest thickness of a continuous and homogeneous SDC coating is achieved at a fraction of SDC-n nanoparticles of 5 wt. %.
Russian Journal of Physical Chemistry. 2025;99(8):1207-1213
1207-1213
Peculiarities of electrokinetic properties of suspensions of nano- and microsized particles
Abstract
The features of electrokinetic properties of suspensions of nano- and micro-sized Ce0.8Sm0.2O1.9 (SDC) particles obtained by laser evaporation and condensation (LIC) and solution combustion methods are presented. The influence of surface nitro groups in the composition of LIC nanoparticles on suspension stabilization and zeta potential value was revealed. The influence of updating the dispersion medium on the properties of suspensions was studied, as well as the addition of cerium nitrate on the electrokinetic properties of suspensions of nano- and micro-sized particles and the character of electrophoretic deposition. The irreversible nature of the loss of stability of the suspension of LIC nanoparticles was established. The influence of the porous character of microsized particles on the electrophoresis process was shown.
Russian Journal of Physical Chemistry. 2025;99(8):1214-1223
1214-1223
ХЕМОИНФОРМАТИКА И КОМПЬЮТЕРНОЕ МОДЕЛИРОВАНИЕ
On the possibility of estimating the constant of dissociation of lithium salts in sulfolane by molecular dynamics method
Abstract
Electrical conductivity of lithium shafts (LiClO₄, LiCF₃SO₃, LiBF₄) in sulfolane solutions was studied by conductometry and molecular dynamics methods. The values of the dissociation constants of lithium salts in sulfolane solutions, the limiting molar electrical conductivities and the lithium cation transfer numbers were calculated based on the data obtained. The values of dissociation constants and limiting molar electrical conductivities calculated from calculated and measured data are in good agreement. Thus, the molecular dynamics method can be used to evaluate the physicochemical properties of electrolyte systems.
Russian Journal of Physical Chemistry. 2025;99(8):1224-1227
1224-1227
PHYSICAL CHEMISTRY OF DISPERSED SYSTEMS AND SURFACE PHENOMENA
Research of surface segregation of components in hard splashes of the Sn-Pb system
Abstract
The processes of surface segregation of components in hard Sn-Pb alloys by electron Auger spectroscopy have been studied. The amplitudes of Sn and Pb Auger peaks in the spectra of solid alloys were measured. Calculations of the surface composition of lead at different volume concentrations and temperatures have been carried out using the experimental data, which made it possible to study the segregation of lead due to changes in these parameters. It was determined that in solid β-solutions surface activity of tin is observed, while in α-solutions significant lead segregation was established. Thus, for solid solutions of 0.12 and 0.22 at. % Pb, a surface concentration of Pb more than 100 times higher than its bulk content is observed.
Russian Journal of Physical Chemistry. 2025;99(8):1228-1232
1228-1232
Effect of hydration on the structure and conductivity of sodium sulfate and potassium chloride matrix electrolytes in a hybrid material of cellulose fabric, macromolecular cyclic aminoacetate and aerosil
Abstract
Electron micrographs were obtained and the conductivity of hydrated and anhydrous matrix electrolytes of sodium sulfate and potassium chloride was measured in a hybrid organo-inorganic material of cellulose tissue and macromolecular cyclic aminoacetates grafted onto aerosil microparticles. The ionic conductivity of anhydrous electrolytes is less than 1×10–7 Cm, and of hydrated ones –1.3×10–3 and 2.3×10–3 cm for Na2SO4 and KCl, respectively. Placers of KCl crystals and Na2SO4 druses are visible on the surface of the structural elements of the material in anhydrous electrolytes. In hydrated electrolytes with KCl, the surfaces are covered with delicate films, and with Na2SO4, they are covered with films of the spread droplet type. These films form solvatocomplex associates involving ligand groups from pore walls and water molecules.
Russian Journal of Physical Chemistry. 2025;99(8):1233-1237
1233-1237
Setting the oxidation state of 99Tc adsorbed on Pt, by X-ray photoelectron spectroscopy
Abstract
An electrochemical method for the concentration of technetium 99mTc ions formed by neutron irradiation of a molybdenum target and required for visualization of internal organs in radiopharmaceutical diagnostics has been proposed. Technetium extraction was carried out by electrochemical method. It was found by X-ray photoelectron spectroscopy that the release of technetium at the cathode, due to electrochemical reduction of pertechnetate ions, occurs in the form of TcO2⋅xH2O. Due to oxidation of surface layers by air oxygen, some amount of Tc(VII) is formed in them: the ratio of Tc(IV): Tc(VII) amounts to 3:7. Under optimal conditions of the process, the efficiency of technetium extraction from the solution containing excess molybdate ions reached 90% during 0.5 h. Since the concentration of molybdenum compounds is small, the reduction of pertechnetate ions occurs with diffusion limitations. The diffusion coefficient of TcO4– ions determined by the rotating disk electrode method was 2.14×10–5 cm2 s–1.
Russian Journal of Physical Chemistry. 2025;99(8):1238-1247
1238-1247
PHYSICAL CHEMISTRY OF SEPARATION PROCESSES. CHROMATOGRAPHY
Physico-Chemical Methods for Analyzing the Content of Trace Impurities in Hydrogen Peroxide
Abstract
For the development of a series of knowledge-intensive areas of industry in the Russian Federation there is a need for hydrogen peroxide with a low content of impurities (up to 1×10–8%). The experience of production and quality control of such hydrogen peroxide at domestic enterprises is currently absent, in this connection the issues of assessment of the possibility of application and adaptation of existing methods of determining the content of microimpurities in hydrogen peroxide and introduction of modern analytical equipment are relevant. Commercially available on the territory of the Russian Federation brands of hydrogen peroxide have been studied.
Russian Journal of Physical Chemistry. 2025;99(8):1248-1257
1248-1257
ELECTROCHEMISTRY. GENERATION AND STORAGE OF ENERGY FROM RENEWABLE SOURCES
Experimental study of electrical conductivity of displacements of MPO3(M2WO4)–V2O5(M-Na, K)
Abstract
The electrical conductivity of eutectic two-component oxide-salt compositions has been studied: KPO3–V2O5; NaPO3 is V2O5; Na2WO4 is V2O5 and K2WO4 is V2O5. The patterns of changes in the logarithm of conductivity and specific conductivity from the inverse value of temperature are revealed. It was revealed that the oxide-salt composition 38 mol % NaPO3–62 mol % V2O5 has the highest electrical conductivity, which is a promising electrolyte for the production of refractory metals, as well as as electrolytes in chemical current sources.
Russian Journal of Physical Chemistry. 2025;99(8):1258-1262
1258-1262
PHOTOCHEMISTRY, MAGNETOCHEMISTRY, MECHANOCHEMISTRY
Studying the photochemical reaction of thiomethylpropyl ketone using the effects of CIDNP
Abstract
This article presents the results of a study of the mechanisms of thiomethylpropyl ketone CH3CSCH2CH2CH3 (1) photoreactions. The main research method was the effect of chemical nuclear polarization (CIDNP), which manifests itself in NMR spectra. If pulsed and laser photolysis makes it possible to study the kinetics of death and accumulation of intermediate products released from the solvent cell, then the use of CIDNP makes it possible to study cellular processes in detail. Elementary reaction acts have been established.
Russian Journal of Physical Chemistry. 2025;99(8):1263-1271
1263-1271
Hydrogen Production from Oxalic Acid on Tantalum-Containing Composites under Irradiation UV and Visible Light
Abstract
The photocatalytic activity of iron-containing composites based on silicon nitride, obtained in the combustion mode of ferrosilicon aluminum (FSA) with various Ta additives (5, 10, 15%), was investigated for hydrogen production from aqueous solutions of H2C2O4 under UV and visible light irradiation. X-ray diffraction method revealed that the main phases of the ceramic matrix of the composites are β-Si3N4 and α-Fe, along with the presence of the semiconductor phase TaON. The morphological features of the samples were studied using electron microscopy. The composite synthesized from FSA with 10% Ta exhibited the highest photocatalytic activity, attributed to its optimal composite structure of Si3N4-TaON-Fe. The mechanisms of H2C2O4 adsorption and photocatalytic generation of H2 from H2C2O4 were investigated on Ta-containing composites synthesized from FSA and a mixture of elemental powders (silicon, aluminum) with 10% Ta in the absence and with the addition of H2O2. It was established that the dependence of photocatalytic H2 evolution on the concentration of H2C2O4 allows the use of the Langmuir-Hinshelwood model. The highest H2 generation rate (6.34 μmol∙min–1) from H2C2O4 is achieved in the presence of H2O2 on the iron-containing composite, which is due to the participation of both heterogeneous and homogeneous photocatalytic processes.
Russian Journal of Physical Chemistry. 2025;99(8):1272-1282
1272-1282