Russian Journal of Physical Chemistry B最新文献

{"title":"Influence of Critical Fluctuations on the Thermodynamic and Transport Properties of Supercritical Fluids: Nonclassical Crossover Equations of State: A Review","authors":"I. M. Abdulagatov,&nbsp;I. Sh. Khabriev,&nbsp;V. F. Khairutdinov,&nbsp;S. M. Rasulov","doi":"10.1134/S1990793124700970","DOIUrl":"10.1134/S1990793124700970","url":null,"abstract":"<p>Based on the hypothesis of scale invariance (scaling), the review describes the main provisions of the modern nonclassical theory of critical phenomena in pure fluids. A detailed description is given to the main types (parametric and six-term or renormalized Landau expansion) of theoretically substantiated crossover equations of state (EoSs) of pure fluids and their application to describe the anomalous behavior of thermodynamic properties in sub- and supercritical fluids. It is shown that the crossover EoS model covers all the characteristic features of the scaling behavior of the thermodynamic properties of pure fluids in the asymptotic region of the critical point in the form of simple power laws with universal critical exponents and transforms into the classical EoSs (in particular, the Landau expansion) with distance from the critical (fluctuation) region. A detailed comparison is made between the predictions of the crossover EoS model and experimental data on the thermodynamic properties for a representative set of supercritical fluids in a wide range of temperatures and pressures. The crossover EoSs of pure fluids are used to quantitatively estimate the boundary of the region of influence of critical fluctuations on the thermodynamic properties, i.e., to evaluate the contribution of the fluctuation component to the experimentally observed anomalous enhancement of the thermodynamic properties of supercritical fluids. An interpretation of supercritical phase transitions (Widom lines) is given based on the concept of large-scale critical fluctuations and crossover theory. Dynamic crossover phenomena are also considered to describe the influence of fluctuations on the critical enhancement of transport properties (thermal conductivity, thermal diffusivity, and viscosity) in sub- and supercritical fluids.</p>","PeriodicalId":768,"journal":{"name":"Russian Journal of Physical Chemistry B","volume":"18 7","pages":"1655 - 1693"},"PeriodicalIF":1.4,"publicationDate":"2025-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143109718","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Peculiarities of Carbamide Hydrolysis and Oxidation in a Water–Oxygen Fluid","authors":"A. V. Shishkin,&nbsp;S. A. Alekhin,&nbsp;M. Ya. Sokol,&nbsp;A. A. Vostrikov,&nbsp;O. N. Fedyaeva","doi":"10.1134/S1990793124700994","DOIUrl":"10.1134/S1990793124700994","url":null,"abstract":"<p>The transformations of carbamide in a water–oxygen fluid (at a carbamide concentration of 0.29–0.39 mol/L, oxygen excess coefficient OR = 0.98–1.25, mole fraction of water 70.0–91.3%) are studied in a batch reactor when heated to 873 K at a rate of 1 K/min. It is shown that the transformations proceed via the mechanism of parallel and sequential reactions, including carbamide hydrolysis, formation and decomposition of cyanuric acid, oxidation of ammonia and products of the decomposition of cyanuric acid. From the analysis of the time dependencies of temperature and pressure, it follows that the oxidation of carbamide occurs predominantly heterogeneously on the surfaces of the reactor wall and the Pt–Rh/Pt-thermocouple inserted into the center of the reaction volume. It is established that excess oxygen (OR = 1.25) or the addition of NaOH leads to an increase in the fraction of nitrogen converted into N₂ and prevents the formation of cyanuric acid. The influence of the concentration of reagents on the ratio of carbamide conversion pathways and the dynamics of heat release is discussed.</p>","PeriodicalId":768,"journal":{"name":"Russian Journal of Physical Chemistry B","volume":"18 7","pages":"1705 - 1712"},"PeriodicalIF":1.4,"publicationDate":"2025-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143109441","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Supercritical Fluid Extraction of Avermectin from Streptomyces avermitilis Using Carbon Dioxide","authors":"A. D. Ivakhnov,&nbsp;T. E. Skrebets","doi":"10.1134/S1990793124701033","DOIUrl":"10.1134/S1990793124701033","url":null,"abstract":"<p>The process of supercritical fluid extraction (SCFE) of avermectin from the bacterial biomass of <i>Streptomyces avermitilis</i> with carbon dioxide is optimized by the method of a full factorial experiment using a second-order rotatable uniform plan. In the planning, the main levels chosen are a pressure of 25 MPa, a temperature of 60°C, and an extraction duration of 100 min. The analysis of the regression equation makes it possible to establish the optimal process parameters: 30 MPa, 85°C, and 133 min. In the control experiment, an extract is obtained with a yield of 13%, containing 41% avermectin. The yield of avermectin of an absolutely dry (a.d.) biomass is 5.36%, which exceeds the extraction yields obtained using organic solvents.</p>","PeriodicalId":768,"journal":{"name":"Russian Journal of Physical Chemistry B","volume":"18 7","pages":"1737 - 1744"},"PeriodicalIF":1.4,"publicationDate":"2025-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143109481","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Adaptation of (h, T) Data To Calculate Some Thermodynamic Properties of SF6 on the Saturation Curve","authors":"E. E. Ustyuzhanin,&nbsp;V. F. Ochkov,&nbsp;S. V. Rykov,&nbsp;I. V. Kudryavtseva,&nbsp;V. A. Rykov","doi":"10.1134/S199079312470101X","DOIUrl":"10.1134/S199079312470101X","url":null,"abstract":"<p>Information is presented on the behavior of the SF₆ density on the binodal in the asymptotic vicinity of the critical point 3 × 10^–6 &lt; τ &lt; 2 × 10^–4, where τ = (<i>T</i>_<i>c</i> – <i>T</i>)/<i>T</i>_<i>c</i> is the relative temperature, and <i>T</i>_<i>c</i> is the critical temperature. The densities of the liquid (ρ_<i>l</i>) and vapor (ρ_<i>g</i>) phases were calculated based on the experimental data of Garrabos et al. (2018) on the height <i>h</i> at which the meniscus is located separating the two phases of the sample in a horizontal cell of diameter <i>d</i> at a temperature <i>T</i> under the terrestrial gravity. The second component of the method was the order parameter <i>f</i>_<i>s</i>(τ) in an analytical form, which meets conditions of the scaling theory (ST) of critical phenomena and is based on the (ρ_<i>l</i>, ρ_<i>g</i>, <i>T</i>) data of Funke et al. (1998) on SF₆ in the range of 10^–3 &lt; τ &lt; 0.3. A number of problems were formulated, including the construction of the dependences ρ_<i>l</i>(τ) and ρ_<i>g</i>(τ) those are consistent with ST and correlate with the (<i>h</i>, <i>T</i>) data at 10^–6 &lt; τ &lt; 10^–3. The relationship was studied between the (<i>h</i>, <i>T</i>) data and the functions  <i>f</i>_<i>s</i>(τ) and <i>f</i>_<i>d</i>(τ) (<i>f</i>_<i>d</i> is the average or rectilinear diameter). The temperatures dependences of ρ_<i>l</i> and ρ_<i>g</i> were constructed in the range of 10^–6 &lt; τ &lt; 10^–3 .</p>","PeriodicalId":768,"journal":{"name":"Russian Journal of Physical Chemistry B","volume":"18 7","pages":"1721 - 1728"},"PeriodicalIF":1.4,"publicationDate":"2025-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143109478","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Supercritical Fluid Extraction of the Lichen Thallus Hypogymnia physodes","authors":"O. S. Brovko,&nbsp;A. D. Ivakhnov,&nbsp;D. V. Zhiltsov,&nbsp;T. A. Boitsova,&nbsp;A. A. Sloboda","doi":"10.1134/S1990793124701057","DOIUrl":"10.1134/S1990793124701057","url":null,"abstract":"<p>The process of supercritical fluid extraction (SCFE) of the thallus of the lichen species <i>Hypogymnia physodes</i> with carbon dioxide in the presence of acetone as a cosolvent is studied. The extraction conditions (temperature, pressure, and duration) on the yields of the extract (EX), phenolic compounds, including low molecular weight phenols (LPs), atranorin (AT), and flavonoids (FVs) are assessed. It is shown that the main amount of extractives (up to 90%) is extracted within 40 min of extraction. The EX yield reaches 156.5 mg/g with a phenolic compound (PC) content of up to 87.3%. The obtained EXs have high antiradical activity (ARA) (up to 225 μmol Trolox-equiv/g). A positive correlation is established between the ARA of the EXs and the content of PCs in them, including AT. The antibacterial activity of the EXs against the gram-positive (<i>Bacillus subtilis</i>) and gram-negative (<i>Escherichia coli</i>, <i>Proteus mirabilis</i>) strains of microorganisms is revealed.</p>","PeriodicalId":768,"journal":{"name":"Russian Journal of Physical Chemistry B","volume":"18 7","pages":"1752 - 1760"},"PeriodicalIF":1.4,"publicationDate":"2025-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143109483","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Transformations of Simple Oxides and Reactions of Isopropanol during Their Interactions under Supercritical Conditions","authors":"Yu. A. Gordienko,&nbsp;M. Yu. Sinev,&nbsp;P. R. Vasyutin","doi":"10.1134/S1990793124700982","DOIUrl":"10.1134/S1990793124700982","url":null,"abstract":"<p>The transformations of a series of simple oxides (Al₂O₃, SiO₂, La₂O₃, CeO₂, PrO₂) during their treatment with isopropanol (<i>i</i>-C₃H₇OH) in an autoclave under supercritical (SC) conditions and with subcritical water vapor were studied. In the presence of water vapor at 350°C, the specific surface areas of oxides decrease most significantly, and some of them (aluminum, lanthanum, and praseodymium oxides) are converted into hydroxides. Praseodymium oxide PrO₂ is almost completely converted within 6 h under the action of <i>i</i>-C₃H₇OH at 350°C, which is accompanied by its reduction and partial conversion into hydroxide. In the case of CeO₂, there were no transformations (including hydration and reduction) in <i>i</i>-C₃H₇OH or water vapor, and the specific surface area did not change. The differences in the behavior of CeO₂ and PrO₂ are explained by the difference in the values of the fourth ionization potential of the Ce and Pr atoms and, as a consequence, in the binding energies of oxygen in higher oxides. The products of conversion of <i>i</i>-C₃H₇OH were detected, whose composition depends on the type of the oxide being treated. The transformation of <i>i</i>-C₃H₇OH is dominant in the presence of Al₂O₃ and mostly gives dehydration products (propylene, diisopropyl ether). In the presence of La, Ce, and Pr oxides, dehydrogenation is dominant, forming acetone and hydrogen (mostly in the presence of La₂O₃). The catalytic nature of isopropanol decomposition in the presence of the given simple oxides was established. Silica SiO₂, which has no pronounced acid-base and redox properties, showed the least activity in the decomposition of <i>i</i>-C₃H₇OH. It was assumed that when treated with SC isopropanol, the oxides are structured under the action of water vapor, which is the product of the transformation of <i>i</i>-C₃H₇OH. The catalytic activity of the autoclave material (stainless steel 12Kh18N10T) in the decomposition of <i>i</i>-C₃H₇OH along both routes—dehydration and dehydrogenation—was noted.</p>","PeriodicalId":768,"journal":{"name":"Russian Journal of Physical Chemistry B","volume":"18 7","pages":"1694 - 1704"},"PeriodicalIF":1.4,"publicationDate":"2025-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143109717","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Molecular Dynamics Simulation of the Raman Spectra of Supercritical Carbon Dioxide","authors":"N. M. Asharchuk,&nbsp;E. I. Mareev","doi":"10.1134/S1990793124701021","DOIUrl":"10.1134/S1990793124701021","url":null,"abstract":"<p>An approach to simulating the Raman spectra of supercritical carbon dioxide was demonstrated. The approach is based on the Fourier analysis of the autocorrelation function of the dipole moment calculated by molecular dynamics. Based on these data, the Raman spectra of carbon dioxide were calculated along the isotherm at 310 K in the pressure range of 0.1–15 MPa. It was determined that, in the Widom delta, the spectral lines are broadened and the pressure dependences of the Raman shifts have extrema. The results obtained agree well with the known experimental data and indicate a significant effect of cluster formation on the macroscopic properties of carbon dioxide in the vicinity of the critical point.</p>","PeriodicalId":768,"journal":{"name":"Russian Journal of Physical Chemistry B","volume":"18 7","pages":"1729 - 1736"},"PeriodicalIF":1.4,"publicationDate":"2025-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143109480","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ferrocene-Modified Siloxane Aerogels","authors":"L. V. Panova,&nbsp;D. A. Lemenovskii,&nbsp;M. I. Afanasov,&nbsp;M. A. Popkov,&nbsp;R. O. Burlutsky,&nbsp;M. M. Brusova,&nbsp;V. N. Talanova,&nbsp;D. N. Kholodkov","doi":"10.1134/S1990793124701045","DOIUrl":"10.1134/S1990793124701045","url":null,"abstract":"<p>An efficient method has been developed for the synthesis of siloxane aerogels with a hybrid structure built into the polymer structure. At the initial stage, a gel was obtained by polycondensation of tetraethoxysilane and ferrocene-containing alkoxysilanes, catalyzed by BF₃ ⋅ Et₂O in acetone. The transformation of gels into aerogels was performed using supercritical carbon dioxide (SC-CO₂). The aerogel samples were characterized in detail by Mössbauer spectroscopy and nitrogen adsorption methods, and the density of the materials was determined. The iron content in the resulting aerogels varied from 3.6 to 8.7 wt % (or 11.9–28.7 wt % ferrocene units).</p>","PeriodicalId":768,"journal":{"name":"Russian Journal of Physical Chemistry B","volume":"18 7","pages":"1745 - 1751"},"PeriodicalIF":1.4,"publicationDate":"2025-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143109482","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Model of Supercritical Fluid Extraction of Vegetable Oil in a Two-Component Approximation","authors":"A. A. Salamatin,&nbsp;A. S. Khaliullina,&nbsp;M. V. Kalinina","doi":"10.1134/S1990793124701008","DOIUrl":"10.1134/S1990793124701008","url":null,"abstract":"<p>This paper presents a model of supercritical fluid extraction of plant triacylglycerides from seeds of high-oil raw material. Oil is considered in a two-component approximation. A three-component solution with CO₂ is described within the framework of the theory of regular solutions. The sign of the interaction energy of the molecules of the oil components makes it possible to distinguish between two thermodynamic equilibrium modes. Mass transfer through the transport channels of an individual particle is described within the framework of the shrinking core model. Constitutive relations between diffusion fluxes and gradients of chemical potentials are formulated within the framework of the Maxwell–Stefan approach. Each component of the oil has its own front and a pair of shrinking core/transport zone. It is shown that the concentration profiles of the oil components are determined not only by diffusion processes, as is typical in the framework of the one-component approximation, but also by the material two-phase equilibrium of individual components.</p>","PeriodicalId":768,"journal":{"name":"Russian Journal of Physical Chemistry B","volume":"18 7","pages":"1713 - 1720"},"PeriodicalIF":1.4,"publicationDate":"2025-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143109479","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Structural and Thermodynamic Parameters of a Biopolymeric Oral Delivery System for a Liposomal Form of a Combination of Nutraceuticals","authors":"M. G. Semenova,&nbsp;A. S. Antipova,&nbsp;E. I. Martirosova,&nbsp;M. S. Anokhina,&nbsp;D. V. Zelikina,&nbsp;N. G. Bogdanova,&nbsp;N. P. Palmina","doi":"10.1134/S1990793124701240","DOIUrl":"10.1134/S1990793124701240","url":null,"abstract":"<p>A liposomal formulation comprising a combination of hydrophobic nutraceuticals (omega-3 docosahexaenoic polyunsaturated fatty acid (DHA) and one of the most active plant antioxidants, namely clove essential oil (CEO)) was prepared using soy phosphatidylcholine (PC). The impact of DHA and CEO on the microviscosity of the bilayer of PC liposomes was investigated through the use of EPR-spectroscopy. Furthermore, the impact of DHA and CEO on the phase state of the bilayer of model liposomes of dipalmitoylphosphatidylcholine was investigated through differential scanning calorimetry. A combination of EPR-spectroscopy and differential scanning calorimetry, was employed to investigate the impact of the encapsulation of liposomes PC−DHA−CEO with a covalent conjugate (C) of sodium caseinate and maltodextrin on the structural state of the bilayer. The structural parameters of a water-soluble supramolecular complex, PC−DHA−CEO−C, formed as a result of the encapsulation process, were also investigated using laser light scattering. These included the molar mass, size, density, architecture and zeta potential of the complex. In addition, the thermodynamic parameters, specifically the osmotic second virial coefficient, were examined. The key structural parameters of this complex have been identified as providing effective protection of PUFAs included in its composition from oxidation by air oxygen.</p>","PeriodicalId":768,"journal":{"name":"Russian Journal of Physical Chemistry B","volume":"18 6","pages":"1572 - 1578"},"PeriodicalIF":1.4,"publicationDate":"2025-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142994661","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}