Thermodynamic Properties Of Solutions Research Articles

Wagner interaction coefficients of nitrogen with chromium and molibdenum in liquid nickel-based alloys

The authors propose a simple theory of thermodynamic properties of liquid nitrogen solutions in alloys of the Fe – Ni – Cr and Fe – Ni – Mo systems. This theory is analogous to the theory for liquid nitrogen solutions in binary alloys of the Fe – Cr and Fe – Ni systems proposed previously by the authors in 2019 and 2021. The theory is based on lattice model of ternary liquid solutions of the Fe – Ni – Cr and Fe – Ni – Mo systems. The model assumes a FCC lattice. Atoms of Fe, Ni, Cr and Mo are deposed in the sites of the lattice. Nitrogen atoms are located in octahedral interstices. The nitrogen atom interacts only with the metal atoms located in the lattice sites neighboring to it. This interaction is pairwise. It is assumed that the energy of this interaction depends neither on composition nor on temperature. It is supposed that the liquid solutions in the Fe – Ni – Cr and Fe – Ni – Mo systems are perfect. Within the framework of the proposed theory, the relation is obtained that expresses the Wagner interaction coefficient between nitrogen and chromium in liquid nickel-based alloys \(\varepsilon _{\rm{N}}^{{\rm{Cr}}}\)(Ni). The right-hand part of the appropriate formula is a function of the Wagner interaction coefficients between nitrogen and chromium \(\varepsilon _{\rm{N}}^{{\rm{Cr}}}\)(Fe) and between nitrogen and nickel \(\varepsilon _{\rm{N}}^{{\rm{Ni}}}\)(Fe) in liquid iron-based alloys. A similar relation is obtained for the Wagner interaction coefficient between nitrogen and molybdenum in liquid nickel-based alloys \(\varepsilon _{\rm{N}}^{{\rm{Mo}}}\)(Ni). According to the first of these formulas, the value \(\varepsilon _{\rm{N}}^{{\rm{Cr}}}\)(Ni) = –21,9 at a temperature of 1873 K is calculated. This corresponds to the value of the Langenberg interaction coefficient \(e _{\rm{N}}^{{\rm{Cr}}}\)(Ni) = –0,108, which coincides with experimental estimate. According to the second formula, the value \(\varepsilon _{\rm{N}}^{{\rm{Mo}}}\)(Ni) = –14,3 is calculated at a temperature 1873 K. This corresponds to the value of the Langenberg interaction coefficient \(e _{\rm{N}}^{{\rm{Cr}}}\)(Ni) = –0,036, which is in satisfactory agreement with the experimental estimate \(\varepsilon _{\rm{N}}^{{\rm{Mo}}}\)(Ni) = –15,1; \(e _{\rm{N}}^{{\rm{Cr}}}\)(Ni) = –0,038.

Fundamental investigations on the ionic transport and thermodynamic properties of non-aqueous potassium-ion electrolytes

Non-aqueous potassium-ion batteries (KIBs) represent a promising complementary technology to lithium-ion batteries due to the availability and low cost of potassium. Moreover, the lower charge density of K+ compared to Li+ favours the ion-transport properties in liquid electrolyte solutions, thus, making KIBs potentially capable of improved rate capability and low-temperature performance. However, a comprehensive study of the ionic transport and thermodynamic properties of non-aqueous K-ion electrolyte solutions is not available. Here we report the full characterisation of the ionic transport and thermodynamic properties of a model non-aqueous K-ion electrolyte solution system comprising potassium bis(fluorosulfonyl)imide (KFSI) salt and 1,2-dimethoxyethane (DME) solvent and compare it with its Li-ion equivalent (i.e., LiFSI:DME), over the concentration range 0.25–2 molal. Using tailored K metal electrodes, we demonstrate that KFSI:DME electrolyte solutions show higher salt diffusion coefficients and cation transference numbers than LiFSI:DME solutions. Finally, via Doyle-Fuller-Newman (DFN) simulations, we investigate the K-ion and Li-ion storage properties for K∣∣graphite and Li∣∣graphite cells.

Determination and Simulation of the Solubility of Bifonazole in 14 Pure Solvents at 283.15–323.15 K

Bifonazole is a derivative of imidazoles with a wide antibacterial spectrum and is widely used for treating various fungi infections. However, in the open literature, the solubility data of bifonazole are rarely reported. Considering the importance of the solubility of bifonazole in its manufacture and applications, the solubility of bifonazole in 8 alcohols and 4 n-alkyl acetates as well as acetonitrile and N, N-dimethylformamide in the temperatures ranging from 283.15 to 323.15 K has been measured with the assistance of a dynamic laser solubility monitoring device in this paper. The measured solubility of bifonazole follows the order of DMF > alcohols > esters > acetonitrile. The relationship between the solubility of bifonazole and temperature was correlated using three semi-empirical and two activity coefficient solubility models. In addition, the thermodynamic mixing properties (ΔmixG, ΔmixH, ΔmixS, γ1∞, and H1E, ∞) of the bifonazole solutions were evaluated in terms of experimental data and Wilson model parameters.

Use of Pitzer’s model to calculate thermodynamic properties of aqueous electrolyte solutions of sulfuric acid

Over this study we calculated the coefficients of activity of different species and the concentration in the presence of H+ ion when H2SO4 is alone in solution. The coefficient of average activity was calculated using the model of Pitzer. The constants of dissociation of these reactions were calculated from the values of the free standard energies. The reaction reaches a balance while producing H+, HSO4- and SO42-. The research reported here concentrated on the effect of some important operational parameters on dissolution process. The parameters were investigated and their ranges are as follows: initial molality ranging from 0.001 to 5 mol.kg-1 and temperatures between 25 and 200°C. Fortran 90 (Mathematical formula translating system) was used to perform all mathematical calculations. The numerical code can be used to calculate the molarity of ion H+ of an aqueous solution of sulfuric acid. The objective of the present work is to optimize the parameters of leaching such as activity of sulfuric acid on the dissociation phenomena.

Thermodynamic properties of aqueous lanthanum sulfate solutions taking into account the association

Thermodynamic properties (the mean activity coefficients, γ±, and the relative apparent molar enthalpies, φL) of lanthanum sulfate aqueous solutions, strongly deviating from the Debye-Hückel limiting law even at lowest experimentally accessible concentrations, can easily and quantitatively be reproduced assuming the formation of two sulfate complexes, LaSO4+ and LaSO42-, whose existence was established in numerous complex formation studies. The analysis was carried out using a simple SIT model for the activity coefficients of ions with only the electrostatic Debye-Hückel terms. Excellent agreement between measured values of γ± and φL and the values of equilibrium constants was obtained by using the following values of equilibrium constants and enthalpy changes of reactions of formation of LaSO4+ (La3++SO42-⇄ LaSO4+) and La(SO4)2- (La3++2SO42-⇄ La(SO4)2-): log10K1o = 3.65 ± 0.05; log10K2o = 5.63 ± 0.2, ΔrH1o = 17.6 ± 1.0 kJ mol−1; ΔrH20 = 28.1 ± 4.0 kJ mol−1. The agreement with literature data is excellent for log10K1o and ΔrH1o and satisfactory for log10K2o and ΔrH2o. With these log10K1o, log10K2o, ΔrH1o and ΔrH2o results the experimental γ± and φL values are reproduced quantitatively.

High-temperature and high-pressure thermodynamic properties of aqueous zinc sulfate solutions

A new method has been proposed to estimate the osmotic and activity coefficients of aqueous electrolyte solutions under non-ambient conditions on the basis of the Pitzer ion-interaction approach using the volumetric data. Following this method, a compact set of Pitzer ion-interaction parameters, valid within the temperature range 293.15 - 373.15 K, and pressure range 0.1 - 10 MPa have been obtained for aqueous ZnSO4 solutions. These parameters helped evaluate the osmotic and activity coefficients of this system to 3.0 mol∙kg−1. The pressure dependences of osmotic and activity coefficients have also been estimated using the equations derived by Rogers and Pitzer (1982). The results obtained by the method proposed in this research agree very well with those calculated using Rogers and Pitzer approach. The advantage of the method proposed here is that it directly provides a compact set of Pitzer ion-interaction parameters required for describing the osmotic and activity coefficients, in contrast to the other method. This study also provided important insight into the ion-association behavior of aqueous ZnSO4 solution with respect to temperature and pressure. Further, the apparent molar enthalpies have been estimated using appropriate temperature derivatives of the Pitzer ion-interaction parameters obtained in this study.

Solubility and Thermodynamics Profile of Benzethonium Chloride in Pure and Binary Solvents at Different Temperatures.

Benzethonium chloride (BTC) has various applications in several industries. The solubility and solution thermodynamic properties of BTC were measured. The solubility of BTC in methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, water, dimethyl sulfoxide, acetic acid, and dimethyl formamide neat solvents and methanol + water and ethanol + water binary solvents at 298.15-318.15 K over an atmospheric pressure was measured. The solubility data of BTC is positively related to the temperature in all selected solvents. The solubility data was fitted by the Apelblat model, λh model, Yaws model, Van't Hoff equation, CNIBS/R-K model, and modified Jouyban-Acree equation. The RMSD and ARD were chosen to evaluate the fitting of each model. The dissolution thermodynamic parameters, enthalpy of the solution, entropy of the solution, and Gibbs energy of the solution were calculated. The solubility data and dissolution thermodynamic parameters of BTC will provide significant guidance for purification, crystallization, and separation in various areas.

Research progress in thermodynamic properties of polyelectrolyte solutions at surfaces and interfaces

聚电解质的表界面行为调控(如表面吸附和粘附)在粘合剂设计、胶体稳定/聚沉、海水淡化和生物医药材 料研发等多个领域发挥着举足轻重的作用. 聚电解质的浓度、刚性、序列结构、盐浓度和表面性质等可设计参 数显著影响着聚电解质的表界面微观结构, 进而决定聚电解质溶液的表界面热力学性质. 为了加速高性能聚电解 质材料的发展, 利用理论方法(如自洽场理论和密度泛函理论等)和计算机模拟(如蒙特卡洛模拟和分子动力学模 拟等)等手段开展高通量、系统性的研究是非常必要的. 本文总结了近年来聚电解质溶液的表界面热力学性质的 相关理论和模拟研究进展, 同时也对该领域未来的发展趋势进行了总结与展望.

Thermodynamic Properties of Solutions in the H2O–Na2SO4–Al2(SO4)3 System

Thermodynamic Properties of Solutions in the H2O–Na2SO4–Al2(SO4)3 System

Thermodynamic Properties of Solutions in the H2O–Na2SO4–Al2(SO4)3 System

The vapor pressure in the H2O–Na2SO4–Al2(SO4)3 system at 15, 25, and 35°C was measured by a static method. The vapor pressure in the H2O–Al2(SO4)3 and H2O–Na2SO4–Al2(SO4)3 systems at 25 and 50°C was measured by the dew point method. A set of parameters of the Pitzer–Simonson–Clegg (PSC) model was determined to describe adequately vapor– liquid equilibria in the H2O–Al2(SO4)3 and H2O–Na2SO4–Al2(SO4)3 systems in the temperature range from 15 to 50°С.

Excess Thermodynamic Properties of Solutions in Ln-Ru (Ln = Nd, Gd, Dy) Binary Systems Based on Quadratic, Exponential and Combined Models Supported by Ab-Initio Calculations

Excess Thermodynamic Properties of Solutions in Ln-Ru (Ln = Nd, Gd, Dy) Binary Systems Based on Quadratic, Exponential and Combined Models Supported by Ab-Initio Calculations

Structure, energetics and dynamics in crowded amino acid solutions: a molecular dynamics study.

A comprehensive understanding of crowding effects on biomolecular processes necessitates investigating the bulk thermodynamic and kinetic properties of the solutions with an accurate molecular representation of the crowded milieu. Recent studies have reparameterized the non-bonded dispersion interaction of solutes to precisely model intermolecular interactions, which would circumvent artificial aggregation as shown by the original force-fields. However, the performance of this reparameterization is yet to be assessed for concentrated crowded solutions in terms of investigating the hydration shell structure, energetics and dynamics. In this study, we perform molecular dynamics simulations of crowded aqueous solutions of five zwitterionic neutral amino acids (Gly, Ala, Thr, Pro, and Ser), mimicking the molecular crowding environment, using a modified AMBER ff99SB-ILDN force-field. We systematically examine and show that the reproducibility of the osmotic coefficients, density, viscosity and self-diffusivity of amino acids improves using the modified force-field in crowded concentrations. The modified force-field also improves the structuring of the solute solvation shells, solute interaction energy and convergence of tails of radial distribution functions, indicating reduction in the artificial aggregation. Our results also indicate that the hydrogen bonding network of water weakens and water molecules anomalously diffuse at small time scales in the crowded solutions. These results underscore the significance of examining the solution properties and anomalous hydration behaviour of water in crowded solutions, which have implications in shaping the structure and dynamics of biomolecules. The findings also illustrate the improvement in predicting bulk solution properties using the modified force-field, thereby providing an approach towards accurate modeling of crowded molecular solutions.

Фазовые состояния твердого раствора (1-x)PbFe-=SUB=-0.5-=/SUB=-Nb-=SUB=-0.5-=/SUB=-O-=SUB=-3-=/SUB=--xPbTiO-=SUB=-3-=/SUB=-. Описание на основе многоминимумных моделей

Based on the composition of two multiminimum models, a statistical model has been developed on the basis of which the formation of tetragonal and monoclinic ferroelectric phases in a solid solution (1-x)PbFe0.5Nb0.5O3-xPbTiO3 has been investigated and described. By selecting the parameters of the model, it was possible to reproduce the diagram T(x) of this solid solution. The peculiarity of the diagram is that when approaching the concentration of x~0.1, the temperatures of the phase transitions between the tetragonal and monoclinic phases decrease sharply, turning to zero. It is shown that the disappearance of the monoclinic phase is due to the specifics of the statistical properties of the eight-minimum model describing the subsystem of octahedra with eight minima. The features of the thermodynamic properties of a solid solution in the vicinity of the morphotropic boundary between the tetragonal and monoclinic phases are also investigated

A QSPR study for predicting θ(LCST) and θ(UCST) in binary polymer solutions

Lower critical solution temperature (LCST) and upper critical solution temperature (UCST) are key thermodynamic properties of binary polymer solutions. In this work, quantitative structure property relationship (QSPR) modeling was employed to predict θ(LCST) and θ(UCST) (LCST and UCST at the limit of infinite molar mass). Based on a series of topological norm descriptors and quantum chemical norm descriptors derived exclusively from the chemical structures of polymers and solvents, four linear topological and spatial LCST-QSPR and UCST-QSPR models were developed. The accuracy, robustness, and predictability of the proposed models were evaluated in detail by various statistical parameters (e.g., R2, MAE, MRE, and RMSE) and validation approaches (e.g., leave-one-out cross validation and Y-randomized validation). Various validation techniques and statistical indicators reveal that the spatial LCST-QSPR and UCST-QSPR models established by adding quantum chemical norm descriptors show better performances. Desirable agreements (Rtraining2 = 0.9423) between calculated and experimental θ(LCST) of 118 training set polymer solutions can be found in the spatial LCST-QSPR model as demonstrated by MRE of 2.65 %. Meanwhile, the spatial UCST-QSPR model shows the performances with MRE of 8.03 % and Rtraining2 of 0.8826 of 87 training set polymer solutions. The comparative results with those of different models from literatures further confirm the advantages of the as-developed models. The presented QSPR models are expected for rapid and accurate prediction of the θ(LCST) and θ(UCST) values of various binary polymer solutions.

Influence of ice formation on the dynamic and thermodynamic properties of aqueous solutions

Influence of ice formation on the dynamic and thermodynamic properties of aqueous solutions

Ultrasonic Investigation of Thermodynamic and Electrochemical Properties of Aqueous Solutions of Ammonium Salts and Comparative Study Among the Chosen Salts

Ultrasonic Investigation of Thermodynamic and Electrochemical Properties of Aqueous Solutions of Ammonium Salts and Comparative Study Among the Chosen Salts

Quasinormal modes, shadow and thermodynamics of black holes coupled with nonlinear electrodynamics and cloud of strings

We construct an exact black hole solution for the Einstein gravity coupled with the nonlinear electrodynamics (which corresponds to the Maxwell electrodynamics in the weak field limit) in the presence of a cloud of strings as the source. We study the thermodynamical properties of the black hole solutions and derive the corrected first-law of thermodynamics. The presence of a cloud of strings does not affect the stability of the present black hole. However, a second-order phase transition exists for this system at a critical horizon radius. Furthermore, we study the quasinormal modes and their shadow radius. In addition, we find that, upon variation, the parameters of the theory show different aspects of the optical characteristics of the black hole solutions.

Solubility parameter and solution thermodynamic properties of Form I Trimebutine maleate in six mono-solvents and three binary mixed solvents at different temperatures

The solubility information of drugs in solution is of great significance in the fields of chemistry and pharmacy. Trimebutine maleate is a commonly used drug for treating gastrointestinal disorders, and its solid–liquid balance data are critical for a preliminary study of industrial application. This study investigated the solubility of medicinal crystal form (Form Ⅰ) of Trimebutine maleate at T = 283.15–328.15 K. The molar fraction solubility of Form Ⅰ in six mono-solvents and three binary mixtures were studied. The modified Apelblat equation, the general Buchowski-Ksiazaczak λh model and the new correlative model were used for correlation analysis of the solubility of Form Ⅰ in mono-solvents. The general cosolvency model and Jouyban-Acree-van't Hoff model were used for correlation analysis of the solubility of Form Ⅰ in binary mixed solvents. By comparing the models, the modified Apelblat equation and the general cosolvency model provided more accurate experimental data for predicting the solubility of Form Ⅰ in mono-solvents and binary mixed solvents, respectively. Finally, the apparent thermodynamic properties were calculated by the van't Hoff analysis.

A Benchmark Database for Mixed-Solvent Electrolyte Solutions: Consistency Analysis Using E-NRTL

Modeling of thermodynamic properties of mixed-solvent electrolyte solutions is challenging. Reliable experimental data are essential for any model development and parametrization. In this work, a benchmark database for (water + methanol/ethanol + alkali halide) mixed-solvent electrolyte solutions is presented. The available experimental data of mean ionic activity coefficient (MIAC) and vapor–liquid equilibrium (VLE) are comprehensively collected and critically evaluated for 61 data sets of 23 solutions. The resulting benchmark database includes 1413 data records from 32 data sets for 13 solutions. The evaluated data sets of the relevant aqueous electrolyte solutions are also presented. A consistent E-NRTL model that satisfies the Gibbs–Duhem equation is utilized for analyzing the data, reconciling the MIAC and VLE data. Based on the database, recommended parameters are obtained for the E-NRTL model.

Tuning the thermodynamic, optical, and rheological properties of thermoresponsive polymer solutions via silica nanoparticle shape and concentration

HypothesisThe shape and quantity of hydrophilic silica nanoparticles (NPs) can be used to tune the microstructure, rheology, and stability of phase-separating polymer solutions. In thermoresponsive polymer systems, silica nanospheres are well-studied whereas anisotropic NPs have little literature precedent. Here, we hypothesize that NP shape and concentration lower the onset of rheological and turbidimetric transitions of aqueous poly(N-isopropyl acrylamide) (PNIPAM) solutions. ExperimentsDifferential scanning calorimetry (DSC), Fourier-transform infrared spectroscopy (FTIR), turbidimetry, and oscillatory rheology are utilized to examine interactions between NPs, PNIPAM, and water and to track changes in phase separation and rheological properties due to NP concentration and shape. FindingsNP addition reduces phase separation enthalpy due to PNIPAM-NP hydrogen bonding interactions, the degree to which depends on polymer content. While NP addition minorly impacts thermodynamic and optical properties, rheological transitions and associated rheological properties are dramatically altered with increasing temperature, and depend on NP quantity, shape, and polymer molecular weight. Thus NP content and shape can be used to finely tune transition temperatures and mechanical properties for applications in stimuli-responsive materials.