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Thermodynamic Properties of Betamethasone Dipropionate
IF 0.7 4区 化学
Russian Journal of Physical Chemistry A Pub Date : 2025-02-11 DOI: 10.1134/S0036024424702911
Yu. A. Sarmini, S. S. Sologubov, N. N. Smirnova, O. V. Stepanova, A.V. Markin
{"title":"Thermodynamic Properties of Betamethasone Dipropionate","authors":"Yu. A. Sarmini,&nbsp;S. S. Sologubov,&nbsp;N. N. Smirnova,&nbsp;O. V. Stepanova,&nbsp;A.V. Markin","doi":"10.1134/S0036024424702911","DOIUrl":"10.1134/S0036024424702911","url":null,"abstract":"<p>Precision adiabatic vacuum and high-precision differential scanning calorimetry (DSC) are used to study the temperature dependence of the heat capacity of betamethasone dipropionate in the range of 6–520 K for the first time. A phase transition of betamethasone dipropionate (melting) is detected in the above range of temperatures, and its thermodynamic characteristics are calculated. The low temperature heat capacity (20 ≤ <i>T</i> ≤ 50 K) is processed on the basis of a multifractal model, and the chain-layered topology of the structure is established. The thermal stability of the steroid hormone is studied via thermogravimetric analysis (TGA). It is found that the temperature at which the substance begins to decompose is 480 K. The experimental data are used to calculate standard thermodynamic functions in the region <i>T</i> → 0 to 480 K for the crystalline and liquid states of betamethasone dipropionate.</p>","PeriodicalId":767,"journal":{"name":"Russian Journal of Physical Chemistry A","volume":"98 14","pages":"3372 - 3378"},"PeriodicalIF":0.7,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143388781","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}
引用次数: 0
Thermodynamic Barriers to the Formation of Critical-Sized Crystalline Embryos in Silicate Glasses 硅酸盐玻璃中临界尺寸晶胚形成的热力学障碍
IF 0.7 4区 化学
Russian Journal of Physical Chemistry A Pub Date : 2025-02-11 DOI: 10.1134/S0036024424702960
G. A. Sycheva
{"title":"Thermodynamic Barriers to the Formation of Critical-Sized Crystalline Embryos in Silicate Glasses","authors":"G. A. Sycheva","doi":"10.1134/S0036024424702960","DOIUrl":"10.1134/S0036024424702960","url":null,"abstract":"<p>The author proposes and describes a way of estimating the magnitude of the thermodynamic barrier to the formation of a critical-sized crystalline nucleus. The frequency of the formation of such nuclei that are stable and capable of further growth determines the rate of nucleation. For nucleation to occur, the nucleus must overcome the thermodynamic barrier. The measure of the magnitude of this barrier is the work needed to create the surface of a nucleus <i>W</i>*, determined from the values of surface energy σ and size <i>r</i>* of the critical nucleus for different temperatures of the preliminary heat treatment of glasses and their subsequent manifestation (crystal growth). The values of σ and <i>r*</i> are obtained from experimentally determined rates <i>I</i><sub>st</sub> of steady-state crystal nucleation; periods τ of non-stationary crystal nucleation, the measure of which is time <i>t</i><sub>ind</sub> of the induction period; and difference Δφ between the specific free energies of the glass and crystal. Values of <i>W</i>* are obtained for a series of silicate glass compositions for promoting crystal nucleation in these glasses.</p>","PeriodicalId":767,"journal":{"name":"Russian Journal of Physical Chemistry A","volume":"98 14","pages":"3404 - 3410"},"PeriodicalIF":0.7,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143388807","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}
引用次数: 0
Non-Monotonic Relaxation Processes in Ga95Nd5 and Ga97Sm3 Melts Ga95Nd5 和 Ga97Sm3 熔体中的非单调弛豫过程
IF 0.7 4区 化学
Russian Journal of Physical Chemistry A Pub Date : 2025-02-11 DOI: 10.1134/S0036024424703023
A. I. Rusanova, L. D. Son, B. A. Rusanov, V. E. Sidorov, A. L. Beltyukov
{"title":"Non-Monotonic Relaxation Processes in Ga95Nd5 and Ga97Sm3 Melts","authors":"A. I. Rusanova,&nbsp;L. D. Son,&nbsp;B. A. Rusanov,&nbsp;V. E. Sidorov,&nbsp;A. L. Beltyukov","doi":"10.1134/S0036024424703023","DOIUrl":"10.1134/S0036024424703023","url":null,"abstract":"<p>Experimental studies of density and viscosity of gallium-rare-earth metal composition alloys with light lanthanides (neodymium and samarium) are investigated for the first time. It is established that these compositions are characterized by long-term non-monotonic changes of properties (relaxation processes) in liquid state. The coefficients of temperature expansion of Ga<sub>95</sub>Nd<sub>5</sub> and Ga<sub>97</sub>Sm<sub>3</sub> alloys and activation energy of viscous flows of their melts are calculated based on experimental data.</p>","PeriodicalId":767,"journal":{"name":"Russian Journal of Physical Chemistry A","volume":"98 14","pages":"3449 - 3453"},"PeriodicalIF":0.7,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143388924","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}
引用次数: 0
Using a Thermodynamic Model of Adsorption to Describe the Behavior of Salts of Modified Humic Acid in Surface Layers
IF 0.7 4区 化学
Russian Journal of Physical Chemistry A Pub Date : 2025-02-11 DOI: 10.1134/S003602442470290X
M. I. Rogatko, S. L. Khil’ko
{"title":"Using a Thermodynamic Model of Adsorption to Describe the Behavior of Salts of Modified Humic Acid in Surface Layers","authors":"M. I. Rogatko,&nbsp;S. L. Khil’ko","doi":"10.1134/S003602442470290X","DOIUrl":"10.1134/S003602442470290X","url":null,"abstract":"<p>A mathematical model of polymolecular adsorption developed for protein solutions at liquid–gas interfaces (V.B. Fainerman, R. Miller, et al.) is used to describe experimental concentration dependences of the change in the equilibrium surface tension and viscoelastic modulus of aqueous solutions of salts of modified humic acids and hymatomelanic acids. It is shown that experimental data are in satisfactory agreement with theoretical estimates. The polymolecular adsorption model of natural polyelectrolytes for solutions of salts of modified humic acids is used to identify correspondence between experimental data and theoretical calculations for bimolecular adsorption, and for the trimolecular adsorption of macromolecules from solutions of salts of hymatomelanic acids at interfaces with air.</p>","PeriodicalId":767,"journal":{"name":"Russian Journal of Physical Chemistry A","volume":"98 14","pages":"3365 - 3371"},"PeriodicalIF":0.7,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143388805","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}
引用次数: 0
Electrochemical Characteristics of LiAsF6 Solutions in Mixed Solvents Based on Dimethyl Sulfoxide
IF 0.7 4区 化学
Russian Journal of Physical Chemistry A Pub Date : 2025-02-11 DOI: 10.1134/S0036024424702972
E. Yu. Tyunina, M. D. Chekunova
{"title":"Electrochemical Characteristics of LiAsF6 Solutions in Mixed Solvents Based on Dimethyl Sulfoxide","authors":"E. Yu. Tyunina,&nbsp;M. D. Chekunova","doi":"10.1134/S0036024424702972","DOIUrl":"10.1134/S0036024424702972","url":null,"abstract":"<p>The electrochemical behaviors of lithium hexafluoroarsenate-based systems in the acetonitrile (AN)–dimethyl sulfoxide (DMSO) and propylene carbonate (PC)–DMSO binary mixtures were compared. The specific electric conductivity of LiAsF<sub>6</sub> solutions in the AN–DMSO mixed solvent with a molal concentration of ionophore of 0.2–1.8 mol/kg and DMSO contents of 0.24–0.68 mole fractions at temperatures of 253.15, 263.15, 273.15, 283.15, 293.15, 303.15, 313.15, 323.15, and 333.15 K was determined for the first time. The concentration dependence of the specific conductivity of the test solutions obeys the Castell–Amis equation. The solvent and ionophore contributions to the activation energy of ionic conductivity were determined based on the application of the transition state theory. In the PC–DMSO and AN–DMSO mixed solvents, LiAsF<sub>6</sub> solutions have a narrower electrochemical window compared to that in solutions of this ionophore in the individual solvents.</p>","PeriodicalId":767,"journal":{"name":"Russian Journal of Physical Chemistry A","volume":"98 14","pages":"3411 - 3420"},"PeriodicalIF":0.7,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143388915","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}
引用次数: 0
Retention Characteristics and Enthalpy of Sorption of Esters of 2,2-Dimethylbutury Acid and Aliphatic Alcohols with Linear Structure C1–C10
IF 0.7 4区 化学
Russian Journal of Physical Chemistry A Pub Date : 2025-02-11 DOI: 10.1134/S0036024424703011
Ya. V. Nikolskiy, V. V. Emelyanov, E. L. Krasnykh, Yu. F. Ivanova, A. A. Ruslyakov
{"title":"Retention Characteristics and Enthalpy of Sorption of Esters of 2,2-Dimethylbutury Acid and Aliphatic Alcohols with Linear Structure C1–C10","authors":"Ya. V. Nikolskiy,&nbsp;V. V. Emelyanov,&nbsp;E. L. Krasnykh,&nbsp;Yu. F. Ivanova,&nbsp;A. A. Ruslyakov","doi":"10.1134/S0036024424703011","DOIUrl":"10.1134/S0036024424703011","url":null,"abstract":"<p>Gas–liquid chromatography on a non-polar phase is used in the 393.2–473.2 K range of temperatures to determine the retention characteristics and enthalpies of sorption for 10 esters of 2,2-dimethylbutyric acid and linear alcohols C<sub>1</sub>–C<sub>10</sub>. A linear dependence of the indices of retention on temperature and the number of carbon atoms in the alcohol molecule is shown for all studied ethers. Enthalpies of evaporation are calculated, and the excess enthalpies of the mixing of ethers are determined.</p>","PeriodicalId":767,"journal":{"name":"Russian Journal of Physical Chemistry A","volume":"98 14","pages":"3444 - 3448"},"PeriodicalIF":0.7,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143388787","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}
引用次数: 0
Ambivalent Thermodynamic States of Water in Solid γ-Cyclodextrin Hydrates
IF 0.7 4区 化学
Russian Journal of Physical Chemistry A Pub Date : 2025-02-11 DOI: 10.1134/S0036024424702807
A. K. Gatiatulin, A. R. Italmasov, M. A. Ziganshin, V. V. Gorbatchuk
{"title":"Ambivalent Thermodynamic States of Water in Solid γ-Cyclodextrin Hydrates","authors":"A. K. Gatiatulin,&nbsp;A. R. Italmasov,&nbsp;M. A. Ziganshin,&nbsp;V. V. Gorbatchuk","doi":"10.1134/S0036024424702807","DOIUrl":"10.1134/S0036024424702807","url":null,"abstract":"<p>The thermodynamics of γ-cyclodextrin hydration was studied using methods of thermal analysis and solution calorimetry. The enthalpy and entropy changes are in a good agreement with two steps of γ‑cyclodextrin hydration isotherm and changes of unit cell volume. The first step of γ-cyclodextrin hydration is more exothermic and has more negative change of entropy while as the second step is less exothermic providing more disorder of water molecules in the hydrate crystal. The kinetic study of γ-cyclodextrin dehydration process revealed the activation energy of this process.</p>","PeriodicalId":767,"journal":{"name":"Russian Journal of Physical Chemistry A","volume":"98 14","pages":"3297 - 3303"},"PeriodicalIF":0.7,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143388794","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}
引用次数: 0
Retraction Note: Effect of Acidity on the Morphology, Structure, and Composition of Ni Nanotubes
IF 0.7 4区 化学
Russian Journal of Physical Chemistry A Pub Date : 2025-02-11 DOI: 10.1134/S0036024424140012
D. B. Borgekov, M. V. Zdorovets, A. L. Kozlovskiy, M. D. Kutuzau, E. E. Shumskaya, E. Yu. Kaniukov
{"title":"Retraction Note: Effect of Acidity on the Morphology, Structure, and Composition of Ni Nanotubes","authors":"D. B. Borgekov,&nbsp;M. V. Zdorovets,&nbsp;A. L. Kozlovskiy,&nbsp;M. D. Kutuzau,&nbsp;E. E. Shumskaya,&nbsp;E. Yu. Kaniukov","doi":"10.1134/S0036024424140012","DOIUrl":"10.1134/S0036024424140012","url":null,"abstract":"","PeriodicalId":767,"journal":{"name":"Russian Journal of Physical Chemistry A","volume":"98 14","pages":"3547 - 3547"},"PeriodicalIF":0.7,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143388929","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}
引用次数: 0
Study of Phase Behavior of Aqueous Nano-Sized Dispersion of n-Eicosane (n-C20H42) 正二十烷（n-C20H42）纳米级水分散体的相态研究
IF 0.7 4区 化学
Russian Journal of Physical Chemistry A Pub Date : 2025-02-11 DOI: 10.1134/S0036024424702856
V. N. Kuryakov, D. A. Mrachkovskaya, E. G. Gudkova
{"title":"Study of Phase Behavior of Aqueous Nano-Sized Dispersion of n-Eicosane (n-C20H42)","authors":"V. N. Kuryakov,&nbsp;D. A. Mrachkovskaya,&nbsp;E. G. Gudkova","doi":"10.1134/S0036024424702856","DOIUrl":"10.1134/S0036024424702856","url":null,"abstract":"<p>Every year, the interest in obtaining new forms of phase change materials (PCM) and studying their physicochemical properties is growing. A topical task is to develop new experimental methods for studying the phase behavior of PCM. The paper presents the results of a study of the phase behavior of a nanosized aqueous dispersion of <i>n</i>-eicosane (C<sub>20</sub>H<sub>42</sub>) using an optical method. Samples of an aqueous dispersion of the studied paraffin were obtained using ultrasonic dispersion without adding surfactants. For the studied sample, the temperatures of phase transitions (melting, crystallization, rotator phases) were determined during heating and cooling. Phase transitions not observed in a bulk sample of the studied paraffin were discovered.</p>","PeriodicalId":767,"journal":{"name":"Russian Journal of Physical Chemistry A","volume":"98 14","pages":"3327 - 3331"},"PeriodicalIF":0.7,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143388785","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}
引用次数: 0
Calorimetric Determination of the Enthalpy of the Reaction of Formation of a Silver(I) Monocomplex with 1-Methyl-2-Mercaptoimidazole
IF 0.7 4区 化学
Russian Journal of Physical Chemistry A Pub Date : 2025-02-11 DOI: 10.1134/S0036024424702947
A. S. Sodatdinova, T. R. Usacheva, D. N. Kabirzoda, S. M. Safarmamadzoda
{"title":"Calorimetric Determination of the Enthalpy of the Reaction of Formation of a Silver(I) Monocomplex with 1-Methyl-2-Mercaptoimidazole","authors":"A. S. Sodatdinova,&nbsp;T. R. Usacheva,&nbsp;D. N. Kabirzoda,&nbsp;S. M. Safarmamadzoda","doi":"10.1134/S0036024424702947","DOIUrl":"10.1134/S0036024424702947","url":null,"abstract":"<p>The study of the reactivity of heterocyclic thioamides exhibiting antithyroid activity is of scientific and practical interest. For objective evaluation of the reactivity of thioamides with biologically active and biogenic metal ions, reliable thermodynamic parameters of complexation are of great importance. The thermodynamic parameters of complexation can be determined by various complementary methods, which increases the reliability of results. The thermodynamic parameters of the reaction of formation of a silver(I) monocomplex with 1-methyl-2-mercaptoimidazole (log<i>K</i>°, ∆<sub>r</sub><i>G</i>°, ∆<sub>r</sub><i>H</i>°, ∆<sub>r</sub><i>S</i>°) were determined by isothermal titration calorimetry in water at <i>T</i> = 298.15 K. The results were compared with the thermodynamic parameters obtained previously by potentiometric titration using the temperature coefficient method to determine the enthalpy of complexation.</p>","PeriodicalId":767,"journal":{"name":"Russian Journal of Physical Chemistry A","volume":"98 14","pages":"3389 - 3393"},"PeriodicalIF":0.7,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143388780","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}
引用次数: 0
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