Thermodynamic Properties Of Solutions Research Articles

Correlation and prediction of thermodynamic properties of dilute solutes in water up to high T and P. II. Normal fluids CO2, C2H4, C2H6, C3H8, n-C4H10, i-C4H10, functional groups CH3 and CH2

Fugacity coefficients of dilute aqueous solutions of six species belonging to normal fluids (CO2, C2H4, C2H6, C3H8, n-C4H10, i-C4H10) as well as functional groups CH3 and CH2 have been evaluated from ambient conditions (298 K, 0.1 MPa) to high temperatures (up to 2000 K) and water densities (up to 1500 kg m−3). The basis of the approach is a correlation developed for the function, A12∞=V2∞/κTRT, that includes known constraints: second virial coefficients at low water densities, hard sphere behavior at high water densities, near-critical principles, and corresponding-states relations. A comparison with literature data at subcritical (Henry's and vapor-liquid distribution constants) and supercritical temperatures (fugacity coefficients) is made. For aqueous CO2, the agreement with literature data is generally satisfactory. It is shown that for other solutes existing disagreements can be traced mostly to the values of the second cross virial coefficients employed in the literature models, suggesting the room for improvement of existing recommendations.

The thermodynamic properties of disorder CuZn solid solution and nonstoichiometric Cu-Zn alloy: Pseudo-atomic lattice inversion potential method

In the process of heating, atomic thermal motion causes an increase in Cu or Zn anti-sites and the degree to which atoms randomly occupy sublattices. The disordered solid solution can be separated into partially disordered and fully disordered solid solutions, and the transition from a fully ordered structure to a fully disordered structure of the solid solution should occur as an evolutionary process of atoms that randomly occupy sublattices to different degrees. In this paper, the concept of “disorder degree” is proposed, and a pseudo-atomic lattice inversion potential method is used to simulate the order to disorder transition of CuZn solid solution. The potential parameters can be obtained using density functional theory (DFT) calculation and Chen’s lattice inversion method. The results indicate that the lattice distortion exhibits a quadratic relationship in which the disorder degree weakens the cohesive energy in the order-disorder transition process. The calculated vibrational entropy difference between the fully ordered B2 and fully disordered A2 CuZn solid solution is 0.24 kB/atom. Furthermore, a new pseudo-atom γ-(Zn or Cu) system is built to calculate the thermodynamic properties of a non-stoichiometry Cu-Zn alloy system, and the results show that the vibrational entropy, specific heat capacity, and bulk modulus exhibit an approximately linear change with Zn concentration. The vibrational entropy and bulk modulus are sensitive to the phase transition, and the slope mutation facilitates the determination of the phase boundary.

Apixaban (I) in several aqueous co-solvent mixtures: Solubility, solvent effect and preferential solvation

Equilibrium apixaban (I) solubility in isopropanol (1) + water (2), ethanol (1) + water (2), acetone (1) + water (2) and methanol (1) + water (2) mixtures was acquired by a shake-flask method from 288.15 K to 328.15 K under atmospheric pressure of 101.2 kPa. At a certain temperature, the highest apixaban (I) solubility in mole fraction scale was observed in neat solvents of acetone/methanol for the acetone/methanol (1) + water (2) solutions; while for the ethanol/isopropanol (1) + water (2) solutions, the solubility data presented a maximum value with the ethanol/isopropanol mass fraction of about 0.8. The determined solubility values were treated by linear solvation energy relationships in order to explain the solvent effect and find its major descriptors. The preferential solvation was studied by the method of inverse Kirkwood–Buff integrals based on some thermodynamic solution properties. In the methanol (1) + water (2) mixture with compositions 0.31 < x1 < 1, ethanol (1) + water (2) mixture with compositions 0.25 < x1 < 0.58, isopropanol (1) + water (2) mixture with compositions 0.25 < x1 < 0.53, acetone (1) + water (2) mixture with compositions 0.20 < x1 < 1 and 1,4-dioxane (1) + water (2) mixture with compositions 0.175 < x1 < 0.570, the preferential solvation parameters for methanol/ethanol/isopropanol/acetone/1,4-dioxane were positive values, indicating that apixaban (I) was preferentially solvated by the co-solvents. It is conjecturable that in these regions apixaban (I) serves as a Lewis acid with the molecules of organic solvents. Moreover, the drug solubility was correlated through the Jouyban-Acree and van’t Hoff-Jouyban-Acree models attaining average relative deviations less than 9.64%.

Solubility measurement, model evaluation and molecular simulations of (R)-(-)-phenylephrine hydrochloride in three binary solvents

In this research work, laser monitoring method was employed to investigate the mole-fraction solubility data of α adrenergic receptor agonists (R)-(-)-phenylephrine hydrochloride (R-PEHC) in three binary solvents namely “methanol (MtOH) + ethanol (EtOH), MtOH + isopropanol (IPOH) and EtOH + IPOH” over the temperature of (278.15–323.15) K with temperature range of 5 K under 0.1 MPa. The results demonstrated that experimental solubility was positively related with temperature while inversely associated with mass fraction of anti-solvents. At the same temperature and mass fraction of anti-solvent, the general solubility order of R-PEHC in binary solvents was MtOH + EtOH > MtOH + IPOH > EtOH + IPOH. Meanwhile, Hansen solubility parameter (HSP) was employed to investigate the solubility order, and the results showed solubility behavior could be analyzed well by selected four solubility parameters (Δδp, Δδh, Δδt and Δδ). Besides, the molecular simulation technology was conducted to investigate solvation free energy (Esol) between R-PEHC and selected solvents. The results showed that experimental solubility differences in various solvents were attributed to the differences in solvation free energy. Moreover, mathcad software (Version: 15) was applied to correlate experimental solubility with respect of temperatures by using five thermodynamic models (UNIQUAC, Wilson, Three-Suffix Margules, Jouyban-Acree-modified Apelblat (J-A-A) and NRTL model). All selected models provided satisfactory goodness-of-fit with R-PEHC solubility data. Furthermore, apparent thermodynamic properties of solutions were calculated based on van’t Hoff equation as well as experimental solubility, the results indicated that dissolution process was always endothermic and entropy-driven.

Equilibrium solubility determination and thermodynamic aspects of aprepitant (form I) in four binary aqueous mixtures of methanol, ethanol, acetone and 1,4-dioxane

This contribution reported the equilibrium solubility of aprepitant (form I) in four binary aqueous mixtures of methanol, ethanol, acetone and 1,4-dioxane acquired through a shake-flask method from 283.15 K to 323.15 K under local atmospheric pressure of 101.2 kPa. At the same mass fraction compositions of methanol/ethanol/acetone/1,4-dioxane and temperature, the mole fraction solubility of aprepitant was greater in (1,4-dioxane + water) mixture than in ethanol/acetone/methanol (1) + water (2) mixtures. The relative importance of solute-solvent and solvent-solvent interactions upon the solubility variation was studied by using the linear solvation energy relationships of solvent effect. The Hildebrand solubility parameter and dipolarity-polarizability of the solvents had the main contributions to the solubility variation in methanol/ethanol/1,4-dioxane + water mixtures; while merely dipolarity-polarizability, in (acetone + water) mixture. The preferential solvation was studied by using the method of inverse Kirkwood-Buff integrals in terms of thermodynamic solution properties. The preferential solvation parameters for methanol, ethanol, acetone and 1,4-dioxane presented positive values in methanol/ethanol/acetone/1,4-dioxane-rich and intermediate compositions in the four mixtures, indicating that aprepitant (I) was solvated preferentially by the methanol/ethanol/acetone/1,4-dioxane. It is conjecturable that in these regions aprepitant (I) acts as a Lewis acid with methanol/ethanol/acetone/1,4-dioxane molecules. Moreover, the drug’s solubility was mathematically represented via the Jouyban-Acree model obtaining the average relative deviations less than 6.21%. Finally, the standard dissolution enthalpies (ΔHsolo) for aprepitant (I) dissolved in solvent mixtures were obtained from the van’t Hoff analysis.

Molecular Mean-Field Theory of Ionic Solutions: A Poisson-Nernst-Planck-Bikerman Model.

We have developed a molecular mean-field theory—fourth-order Poisson–Nernst–Planck–Bikerman theory—for modeling ionic and water flows in biological ion channels by treating ions and water molecules of any volume and shape with interstitial voids, polarization of water, and ion-ion and ion-water correlations. The theory can also be used to study thermodynamic and electrokinetic properties of electrolyte solutions in batteries, fuel cells, nanopores, porous media including cement, geothermal brines, the oceanic system, etc. The theory can compute electric and steric energies from all atoms in a protein and all ions and water molecules in a channel pore while keeping electrolyte solutions in the extra- and intracellular baths as a continuum dielectric medium with complex properties that mimic experimental data. The theory has been verified with experiments and molecular dynamics data from the gramicidin A channel, L-type calcium channel, potassium channel, and sodium/calcium exchanger with real structures from the Protein Data Bank. It was also verified with the experimental or Monte Carlo data of electric double-layer differential capacitance and ion activities in aqueous electrolyte solutions. We give an in-depth review of the literature about the most novel properties of the theory, namely Fermi distributions of water and ions as classical particles with excluded volumes and dynamic correlations that depend on salt concentration, composition, temperature, pressure, far-field boundary conditions etc. in a complex and complicated way as reported in a wide range of experiments. The dynamic correlations are self-consistent output functions from a fourth-order differential operator that describes ion-ion and ion-water correlations, the dielectric response (permittivity) of ionic solutions, and the polarization of water molecules with a single correlation length parameter.

Molecular Force Field Development for Aqueous Electrolytes: 2. Polarizable Models Incorporating Crystalline Chemical Potential and Their Accurate Simulations of Halite, Hydrohalite, Aqueous Solutions of NaCl, and Solubility.

The current state-of-the-art force fields (FFs) for Na+ and Cl- ions are not capable of simultaneously predicting the thermodynamic properties of the aqueous solution and the crystalline phase. This is primarily due to an oversimplification of the interaction models used but partially also due to the insufficient parametrization of the FFs. We have devised a straightforward and simple parametrization procedure for determining the ion-ion interaction parameters in complex molecular models of NaCl electrolytes which involves fitting the density, lattice energy, and chemical potential of crystalline NaCl at ambient conditions. Starting from the AH/BK3 and MAH/BK3 FFs, the parametrization approach is employed to develop a complex and accurate polarizable molecular model for the NaCl electrolyte by parametrizing the ion-ion interactions. The performance of the refined polarizable NaCl FF is assessed by evaluating the different thermodynamic and mechanical properties of the crystal, density of crystalline and molten NaCl, along with the melting temperature, properties of aqueous solutions, and the structure and stability of hydrohalite. The simulation results confirm the superiority of the refined FF in comparison with the existing state-of-the-art FFs to accurately predict a wide range of system properties in different NaCl phases, including NaCl aqueous solubility. The refined FF may find applications in the accurate simulations of NaCl electrolytes including inhomogeneous environment, phase equilibria and interfaces, and metastable states. Finally, the parametrization strategy is robust and general and can be used to devise molecular models for other electrolytes.

Thermodynamic Properties of Phases and Phase Equilibria in the H2O–HNO3–UO2(NO3)2–Th(NO3)4 System

A set of Pitzer parameters was obtained to accurately describe the thermodynamic properties of solutions in the H2O–UO2(NO3)2–Th(NO3)4–HNO3 system at 25°С and represent the thermodynamic properties of liquid phases in the H2O–Th(NO3)4–HNO3 subsystem in the temperature range 25–50°С. Solubility products were calculated for crystal hydrates Th(NO3)4 · 6H2O and UO2(NO3)2 · 3H2O to predict the solubilities of these compounds in those solutions over a wide concentration range.

The thermodynamic properties of lithium carbonate aqueous solution studied by the potentiometric method

The electromotive forces (EMF) of the electrochemical cell of the form CO32– -ISE | Li2CO3 (m) + H2O + CO2↑ | Li+- ISE were measured at temperatures (283, 298, 313) K and solution concentrations from (0.01 to 0.16) mol∙kg−1 by the potentiometric method with ion-selective electrodes (ISE). The EMF measurements were carried out at a fixed partial pressure of CO2 (10−4 ÷ 10−1 MPa). It was demonstrated that the extended Debye – Hückel model for the mean ionic activity coefficients (γ±) of Li2CO3 in solution allows adequate description the measured EMF.

Screen the elastic and thermodynamic properties of MAX solid solution using DFT procedue: Case study on (Ti1-xVx)2AlC

As one of Mn+1AXn (MAX) family, where M is an early transition metal, A is an A-group element, and X is either C or N and n = 1, 2, and 3, Ti2AlC is a promising candidate material for nuclear energy industry due to its unique features such as elastically stiff, good electrical conductivity, high thermal conductivity and excellent resistance to high temperature oxidation and corrosion. However, the mechanical and thermal properties of Ti2AlC compound are expected to be improved. For the first time, the effect of V content on the structural, elastic, electronic and thermodynamic properties of the (Ti1-xVx)2AlC (x = 0, 0.25, 0.50, 0.75 and 1.00) solid solutions was examined systematically and their compression behavior under 50 GPa was studied using density functional theory (DFT). The optimized lattice constants agree well with the experimental values and decrease with the increase of V content. The (Ti1-xVx)2AlC solid solutions are compressible along both a and c directions in the pressure range of 0–50 GPa. Calculated elastic constants verified mechanical stability under 50 GPa. The constant C44, directly related to the valence electron concentration, is found to increase with increasing V content. The bulk modulus, shear modulus, Young's modulus and Vickers hardness are found to reach a significant maximum value respectively when V content is 75%, and the reason is studied. The shear anisotropy factors show that (Ti1-xVx)2AlC compounds containing Ti and V are more anisotropic than Ti2AlC, and they have a tendency towards improved ductility. The metallic behaviors of (Ti1-xVx)2AlC solid solutions are confirmed by analyzing the electronic band structures and density of states. The thermal properties imply that the (Ti0.25V0.75)2AlC is expected to be more thermally conductive due to its highest Debye temperature of 771K of the five compounds. In addition, the bulk modulus, shear modulus, Young's modulus and Debye temperature increase with the increase of pressure under 50 GPa. The results reveal that the mechanical properties of Ti2AlC are improved much better than the thermal properties by the inclusion of V. Especially, the (Ti0.25V0.75)2AlC MAX phase in (Ti1-xVx)2AlC solid solutions is probably the most suitable candidate material for mechanical and thermal applications at high temperature.

Thermodynamic properties of solid solutions in the PbSe—AgSbSe2 system

The results of the study of the PbSe—AgSbSe2 system by measuring the emf of concentration chains with respect to PbSe in a temperature range of 300–450 K are presented. The formation in the system of a wide (37–100 mol.% AgSbSe2) region of solid solutions based on AgSbSe2 is shown. The partial thermodynamic functions of PbSe and lead in the alloys are calculated from the equations of the temperature dependences of the emf. The standard thermodynamic functions of formation and standard entropies of solid solutions (2PbSe)x(AgSbSe2)1−x (x = 0.4, 0.6, 0.8, and 0.9) are calculated by the integration of the Gibbs—Duhem equation over the PbSe—AgSbSe2 section using the literature data on the corresponding thermodynamic data for compounds PbSe and AgSbSe2.

Development of a solvent-polarizable three-dimensional reference interaction-site model theory.

Solvent polarization around a polar solute molecule plays an essential role in determining the electronic and thermodynamic properties of solutions. In this study, a solvent-polarizable model in response to solute polarization is proposed, which is coupled with a three-dimensional reference interaction-site model theory. The charge-response kernel is used to describe solvent polarizability, and four different coupling schemes are assessed. The most feasible behavior scheme among them is the one that incorporates responses not only to solute polarization but also to solute-induced solvent polarization. The numerical results indicated that solvent molecules near the polar solute show significant polarization, and therefore, the model proposed here is useful for considering the solvation process and thermodynamics of polar solute molecules.

Solubility of sinapic acid in various (Carbitol + water) systems: computational modeling and solution thermodynamics

The solubility and solution thermodynamic properties of a “bioactive nutraceutical” sinapic acid (SA) in different “2-(2-ethoxyethoxy)ethanol (Carbitol®) + water” mixtures were investigated. The “mole fraction solubilities (xe)” of SA in various “Carbitol + water” systems were determined at “T = 298.15–318.15 K” and “p = 0.1 MPa.” The measured xe values of SA were found well regressed by “Apelblat, van’t Hoff, Yalkowsky, Jouyban–Acree and Jouyban–Acree–van’t Hoff” models with mean percent deviations of < 4.0%. The maximum xe value of SA was recorded in pure Carbitol (4.15 × 10−2 at T = 318.15 K), and the minimum one was estimated in neat water (6.28 × 10−5 at T = 298.15 K). The regressed results were found to be in accordance with experimental results of SA. Using activity coefficients, mixing thermodynamic parameters of SA were determined. The results showed spontaneous dissolution of SA in most of the cosolvent mixtures.

Measurement and modelling of water activities of the {CuSO4 + poly(ethylene glycol) + H2O} system in the temperature range from 303.15 to 333.15 K

In this work, thermodynamic properties of unsaturated solutions of (CuSO4 + PEG 2000 + H2O) system at (303.15, 313.15, 323.15 and 333.15) K were studied. The concentration range of the solutions was from 0.01 to 0.05 mass fraction of CuSO4 and from 0.15 to 0.3 mass fraction of poly(ethylene glycol) with an average molar mass of 2000 g/mol. Water activities were correlated with the modified Pitzer model, obtaining a good agreement between the experimental and correlated data.In addition, water activities predictions for the (CuSO4 + PEG 4000 + H2O) and (CuSO4 + PEG 2000 + H2O) systems were performed with the modified Pitzer and extended UNIQUAC models, respectively, showing that both thermodynamic models operate independently of the molar mass of the polymer used.The effect of the cations on the water activities of different (salt + PEG 4000) systems was evaluated, showing a close relation with the Molar Gibbs Energies of Hydration of the respective cations.The salting effect and Gibbs Energy change (ΔG) of different ternary systems showed that a salting-out effect occurs in all the studied systems.

Selective Lanthanide Sensing with Gold Nanoparticles and Hydroxypyridinone Chelators.

The octadentate hydroxypyridinone chelator 3,4,3-LI(1,2-HOPO) is a promising therapeutic agent because of its high affinity for f-block elements and noncytotoxicity at medical dosages. The interaction between 3,4,3-LI(1,2-HOPO) and other biomedically relevant metals such as gold, however, has not been explored. Gold nanoparticles functionalized with chelators have demonstrated great potential in theranostics, yet thus far, no protocol that combines 3,4,3-LI(1,2-HOPO) and colloidal gold has been developed. Here, we characterize the solution thermodynamic properties of the complexes formed between 3,4,3-LI(1,2-HOPO) and Au3+ ions and demonstrate how under specific pH conditions the chelator promotes the growth of gold nanoparticles, acting as both reducing and stabilizing agent. 3,4,3-LI(1,2-HOPO) ligands on the nanoparticle surface remain active and selective toward f-block elements, as evidenced by gold nanoparticle selective aggregation. Finally, a new colorimetric assay capable of reaching the detection levels necessary for the quantification of lanthanides in waste from industrial processes is developed based on the inhibition of particle growth by lanthanides.

Measurement and Modeling of the Solubility of N,N-Dibenzylhydroxylamine in 17 Solvents from T = 273.15 to 323.35 K and Thermodynamic Properties of Solution

In this work, the solubility of N,N-dibenzylhydroxylamine (DBHA) in 17 pure solvents, including methanol, ethanol, n-propanol, n-butanol, acetone, ethyl acetate, dichloromethane, acetonitrile, isopropanol, n-octanol, cyclohexanone, 1,2-dichlorobenzene, toluene, isobutanol, n-pentanol, 1,2,4-trichlorobenzene, and tetrahydrofuran, was determined by a static gravimetric method with the temperature ranging from 273.15 to 323.35 K under atmospheric pressure. The solubility of DBHA was positively related to temperature in all selected solvents. Besides, the experimental solubility data were correlated with four thermodynamic models, i.e., the modified Apelblat equation, λh equation, nonrandom two-liquid (NRTL) equation, and the Wilson equation. The results indicated that all of the models could give satisfactory results and the NRTL equation provided the best fitting result. Furthermore, the dissolution thermodynamic parameters in the used solvents, including the Gibbs energy (ΔdisG), molar enthalpy (ΔdisH), and molar entropy (ΔdisS), were calculated according to the Wilson model, and it turned out that the dissolution process of DBHA was endothermic.

Kerr–Newman–NUT–Kiselev black holes in Rastall theory of gravity and Kerr/CFT correspondence

We present a new twisted rotating black hole solution by performing Demiański–Newman–Janis algorithm to the electrically and dyonically charged black hole with quintessence in Rastall theory of gravity. Using our black hole solution, we argue that Rastall gravity is not equivalent with Einstein gravity. For further explanation, the black hole properties such as the horizon and ergosphere are studied for which there are some different properties for those theories. Some thermodynamic properties of the black hole solution are also discussed. At the end, considering the Kerr/CFT correspondence is valid for our black hole solution, the central charge from the CFT of this extremal solution is derived.

Thermodynamic and Acoustical Properties of Solutions of Tetra Butyl Ammonium Iodide in Various Alcohols at Different Temperatures

Thermodynamic and Acoustical Properties of Solutions of Tetra Butyl Ammonium Iodide in Various Alcohols at Different Temperatures

Measurement, Correlation and DFT study for Solubility of Glutaric acid in Water + Ethanol binary solvents at T = (293.15 to 313.15) K

The solubility of Glutaric acid in water, ethanol and water + ethanol binary solvent was determined over the entire composition range between 0 to 1 weight fraction of ethanol at (293.15, 295.15, 298.15, 300.15, 303.15, 305.15, 308.15, and 313.15) K. The Apelblat and van't Hoff equation was used to correlate the experimental solubility data and the equations provide better correlation in this study. The activity coefficients were calculated to evaluate molecular solute-solvent interaction. DFT was carried out to correlate solubility in various solvents system. Thermodynamic properties (%ζH, %ζTS) of solution were calculated using van't Hoff equation.

Thermal analysis of water confined in fully and partially saturated cement paste

The main object of the presented research is to apply thermal analysis in order to investigate microstructure of hardened cement paste. The test is conducted by means of differential scanning calorimetry on samples stored in various relative humidity levels as well as the fully saturated ones. The obtained results describe water solidification beginning at several different temperatures, which implies complex nature of cement paste microstructure. The recorded thermograms consist of two main peaks, which clearly indicate the division into capillary and gel pores. Additionally, the thermodynamic properties of actual pore solution confined in cement matrix are investigated. The obtained results indicate ions present in the liquid strongly affects its phase transition temperature as well as amount of ice formed during such the phase change.