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Densities of urea (U) and tetramethylurea (TMU) solutions in formamide (FA) and water with a solute molality of up to ∼2 mol kg–1 were measured at T = 288.15, 298.15, 308.15, 318.15, and 328.15 K a...

The densities of urea (U) and tetramethylurea (TMU) solutions in ethylene glycol (EG) at the solute molality range up to 1.5 mol·kg−1 were measured with the uncertainty of 0.03 kg·m−3 at T = (288.15, 298.15, 308.15, 318.15 and 328.15) K and p = 99.6 kPa using a vibrating-tube densimeter. The standard partial molar volumes and isobaric expansibilities as well as parameters of the solvent-induced solute–solute pair interactions for both ureas were calculated. The results were discussed in terms of hydrophilic and hydrophobic nature of U and TMU, respectively, and also on the background of the suggestion that EG, like liquid water, forms the hydrogen bond spatial network.

The solubility of hydrogen sulfide (H2S) in N-methylimidazole (NMI) and gamma-butyrolactone (GBL) were experimentally measured. Gas concentrations were systematically measured by isochoric saturation method at temperatures from (303.15 to 353.15) K and pressure from vapour pressure of solvent up to about 1.2 MPa, in all experiments mole fraction of dissolved gas has been measured with uncertainty order of 10−3. In order to construct a GA-artificial neural network (ANN)-based model, the H2S solubility, molality and total pressure were selected for the output. The precision of the GA is compared with experimental data and also with thermodynamic modelling approach in which Peng-Robinson-Stryjek-Vera (PRSV) cubic equation of state with Panagiotopoulos-Reid combining rule has been chosen for this purpose.

The purpose of this paper is to determine the amount of water in ionic liquid aqueous solutions that does not form hydrogen bonds (that is to say, free water). Here, the amount of free water was determined in mixtures of water and four ionic liquids based on the imidazolium cation: 1-Butyl-3methylimidazolium acetate, 1-Butyl-3methylimidazolium bromide, 1-Butyl-3methylimidazolium chloride, and 1–3, dimethyl-imidazolium chloride. Their ionic liquid mass fraction was between 0% and 80%. The amount of free water in the mixtures was determined from the concentration profiles obtained by analysing the near infrared spectra of the mixtures between 800 and 1070 nm using multivariate curve resolution-alternating least squares. The absorption band characteristic of the OH- group in the water is present in the spectral region considered. The analysis was done at three temperatures: 298.15, 313.15 and 333.15 K. The major conclusions obtained from a comparative analysis of the results are these: a) the length of the alkyl chain significantly affects the hydrophobicity of the cations when the molality of the ionic liquid in the solutions is higher than 1.435 mol/kg. b) for the solutions with the same cation, the amount of free water in the chloride solutions is lower than in the acetate and bromide solutions when the temperature is lower than 333.15 K. At this temperature, the capacity of acetate and bromide solutions to interact with water is the same. Between 298.15 and 333.15 K, the ionic liquid concentration at which there is no free water in the solutions ranges between 62.70% and 59.59% for the 1–3, dimethylimidazolium chloride, 66.72% and 87.75% for the 1-Butyl-3methylimidazolium chloride, 69.76% and 78.36% for the - 1-Butyl-3methylimidazolium bromide and between 69.77% and 78.26% for the 1-Butyl-3methylimidazolium acetate. So, the ionic liquid with the greatest capacity to retain water is the 1–3, dimethylimidazolium chloride.

In this study, we present the modeling of the hydrate dissociation pressures for methane, ethane, and propane in the presence of NaCl, KCl, and CaCl2 aqueous solutions using a modified equation of state for aqueous electrolyte solutions with partial ionization (AES-PI) coupled with the van der Waals–Platteeuw theory. The proposed thermodynamic model includes a linear correlation for describing the ionic hydration process as a function of the pressure and molality. The proposed approach is capable of representing the inhibition effect at different salt concentrations. The results showed an excellent agreement between the experimental data and the calculated values at different conditions typical of the deepwater environment.

Industrialization and modernization have led to an increasing trend of greenhouse gas emissions entering the atmosphere. Consequently, many countries are imposing strict environmental regulations due to increasing concern on the climate change, and a significant amount of research is being conducted to tackle this problem. Carbon capture and sequestration are one of the major methods, which can remarkably contribute to this issue since a major greenhouse gas in Earth's atmosphere is carbon dioxide (CO2). The general objective of this work was to investigate the significance of potential use of aqueous salt solutions for capturing CO2 by developing an accurate model for estimation of this phenomenon. In particular, 608 experimental data of CO2 solubility in aqueous solutions of salts as a function of temperature, pressure, salt solution concentration (molality), hydrogen bond acceptor count of salts, molecular weight of salts, and complexity value of the salts were collected from the literature. Four state-of-the-art computational methods (LSSVM, ANN, PSO-ANFIS and GA-ANFIS) were employed to examine their predictive capability for the problem. The results reveal that the LSSVM offers the highest accuracy with R2 = 0.9927 and %AARD = 5.37. Although the neural network and fuzzy interface systems are more complex approaches, the superiority of the LSSVM method for the problem under study demonstrates the easy nature of this phenomenon. Thus, the LSSVM model is recommended for estimating the CO2 solubility in aqueous salt solutions because not only it has more accuracy, but also it is easy to apply, has less mathematically complicated and less time-consuming.

Densities ρ, have been measured for l -Proline in aqueous Metformin Hydrochloride solutions of (0.05, 0.10, 0.15 and 0.20 M) mol kg−1 at T = 298.15–318.15 K. Apparent molal volumes Vφ have been determined from the experimental densities. These data have been used to calculate several thermodynamical parameters such as standard partial molal volume Vφ0, transfer volume ΔtrVφ0, hydration number nH, the second derivative of infinite dilution of partial molal volume with respect to temperature, viz., ∂2Vφ0/∂T2. Furthermore apparent molar expansibility E0, thermal expansion coefficient, α2 and the pair and triplet interaction coefficient have been calculated and reported. These results interpreted through a co-sphere overlap model indicate the presence of strong solute-co-solute interactions in the reported systems.

The relative humidities on ternary NaCl-sucrose-H2O solution of 0.5, 1.0, 2.0, 4.0 and 5.5 mol·kg−1 of sucrose have been determined by the hygrometric method at 298.15 K in the molality range from 0.5 to 6.0 mol·kg−1 of NaCl. The obtained data allow the deduction of the water activities and osmotic coefficients. The experimental results are compared with the predictions of the extended composed additivity (ECA) rule, the Lin et al. equation, and Lietzke and Stoughton (LS II) models. The obtained results were interpreted by using Pitzer-Simonson-Clegg model. The four mixture parameters are determined and used to predict the activity coefficients of NaCl and sucrose in the mixed solution. The solubility, excess Gibbs energy and The Gibbs energies of transfer of sodium chloride are also calculated for this system.

A phenomenological model is developed to take into account the effect of hydration complexes on the properties of electrolytes. The results of validation of the model are demonstrated for experimental pH values of aqueous solutions of sodium metaborate within a molal concentration range of 10−3–4.0 mol kg−1 at the temperatures 20, 25, and 50 °C.

This paper focuses on the thermochemical behavior of two derivatives of 1,2,4-triazole which is often considered as a potential synthetic platform to develop novel antitumor or antimicrobial drugs, i.e., 3,5-diamino-1,2,4-triazole (compound 1) and 3,5-diamino-1-phenyl-1,2,4-triazole (compound 2). Experimental enthalpies of solution in water have been determined calorimetrically over the physiological temperature range. These quantities are used to compute standard enthalpies and heat capacities of solution. Standard partial molal heat capacities of solution are calculated from the heat capacities of solution and experimentally determined heat capacities of solid heterocycles. The results obtained are compared with those for hydrophilic urea and hydrophobic benzene and briefly discussed.

Experimental results of the osmotic coefficients of aqueous solutions of 1-ethyl-3-methylimidazolium ethylsulfate [EMIM][EtSO4], 1-ethyl-3-methylimidazolium methylsulfate [EMIM][MeSO4], 1-ethyl-3-methylimidazolium tosylate [EMIM][Tos], 1,3-dimethylimidazolium methylsulfate [MMIM][MeSO4], tributylmethylphosphonium methylsulfate [TBMP][MeSO4] and triisobutylmethylphosphonium tosylate [(iBu)3MP][Tos] obtained by vapor pressure osmometry (VPO) at 298.15 K and at atmospheric pressure are reported in this work. From this data water activity (aw), vapor pressure (p), mean molal activity coefficients (γ±), Gibbs free energy due to mixing (ΔGmix) and excess Gibbs free energy change (ΔGE) are calculated. The activity coefficient data obtained are correlated with McMillan-Mayer theory and Pitzer model. The results obtained are elucidated in terms of ion association and structural characteristics of ILs.

The absorption capacity of the ionic liquid 1-ethyl-3-methylimidazolium tetrafluoroborate ([C2mim][BF4]) for the single gases carbon dioxide and hydrogen sulfide was measured at temperatures from (298 to 353) K and pressures up to about 2.0 MPa. The corresponding molar volumes of CO2/H2S-saturated liquid phase were also measured in the above temperature and pressure ranges. At the same temperature and pressure, the solubility of hydrogen sulfide in [C2mim][BF4], expressed on the molality scale, is more than three times that of CO2. The Henry’s law constants were determined from the new experimental data, which in turn were used to derive the change of some thermodynamic functions for dissolution of the gases in that particular ionic liquid. The partial molar volume at infinite dilution for CO2/H2S + [C2mim][BF4] mixtures was estimated from the measured molar volumes. The new experimental data were correlated by using two models: (a) a model comprised of the extended Henry’s law and Pitzer’s virial expansion for the excess Gibbs energy, and (b) a generic Redlich-Kwong (GRK) type of cubic equation of state. Both models adequately good correlate the experimental data; however, the first model shows a slightly higher correlative accuracy than the second one. The selectivity of [C2mim][BF4] to separate CO2 and H2S is also discussed on the basis of correlation results.

The emf of the cell is measured to investigate the HCl + NaCl + H2O + CH3OH mixed electrolyte systems. The experimental data are obtained over the electrolyte molality ranging from 0.005 mol kg–1 up to about 3.5 mol kg–1, at 298.15 ± 0.01 K, by using a cell containing a pH and a silver chloride electrode in different alcohol mass fractions x(CH3OH) in H2O (where x = 0.10, 0.20, 0.30, 0.40, and 0.50). The mean activity coefficients of HCl in the mixtures are computed. Modeling is implemented by the classical Pitzer (CP) equation and original Pitzer (OP) equation that are included by the additional terms which are arising from interactions of neutral species and finally the modified Pitzer equation by Merida et al. (MP). The different aspects of proper parameter choosing in fitting processes especially for pure and mixed electrolytes in mixed solvent systems are signified in the results.

This paper deals with liquid-liquid equilibrium of binary {1-butanol + water} and ternary {1-butanol + aqueous sugar solutions} systems in both water-rich and butanol-rich environments. Immiscibility region of 1-butanol-water system is expanded by addition of sugars, and this effect becomes stronger by increasing hydrophilicity and molality of sugars. The soluting-out ability of sugars follows the order maltitol ≈ maltose > sucrose > D-(+)-glucose > D-(−)-fructose > xylitol > D-(+)-xylose. The experimental cloud point data were successfully correlated by Setschenow's equation. Thermodynamic functions and relative contributions of entropy and enthalpy to Gibbs free energy of clouding were calculated. From the obtained results, the clouding process of 1-butanol in water mixtures is more spontaneous than that of water in 1-butanol ones. The presence of sugars, in both water-rich and alcohol-rich environments, leads to a more spontaneous liquid-liquid demixing process. The clouding process in the water-rich region is entropy-driven, while in the butanol-rich region is enthalpy-driven.

A simple equation is derived for the prediction of the water activity as a function of the molal concentrations of a multicomponent mixture, a1(m2 , m3 ,.., mn+1). It consists basically of a series expansion whose coefficients are determined from the limiting behavior imposed by the thermodynamics of solutions. The validity of this equation was verified on 96 binary, ternary and quaternary systems involving electrolytic and molecular solutes as well as solutions containing both electrolytes and nonelectrolytes. The error was always lower than 1% for solutions with a 1 ≥ 0.90. For electrolytic solutions its applicability range is moderately concentrated and dilute solutions (maximum molality m max ≤ 1 mol·kg−1), while for the case of molecular solutes it extends to significantly more concentrated mixtures (3 ≤ m max /mol·kg−1 ≤ 6). Moreover, it also allowed the derivation of a generalized form of Zdanovskii's rule for multicomponent systems involving both electrolytic and molecular solutes as well as the verification of the Frolov?Rard hypothesis. Finally, the equation was used for the estimation of the vapor pressure of ternary solutions of non-volatile solutes, showing better descriptive capabilities than those calculated by the application of the perturbed-chain statistical associated fluid theory (PC-SAFT). Fil: Gennero, Maria Rosa. Universidad Nacional del Litoral. Instituto de Química Aplicada del Litoral. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Química Aplicada del Litoral.; Argentina Fil: Chialvo, Abel Cesar. Universidad Nacional del Litoral. Instituto de Química Aplicada del Litoral. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Química Aplicada del Litoral.; Argentina

Thermodynamic properties of aqueous species are essential for modeling of fluid-rock interaction processes. The Helgeson-Kirkham-Flowers (HKF) model is widely used for calculating standard state thermodynamic properties of ions and complexes over a wide range of temperatures and pressures. To do this, the HKF model requires thermodynamic and electrostatic models of water solvent. In this study, we investigate and quantify the impact of choosing different models for calculating water solvent volumetric and dielectric properties, on the properties of aqueous species calculated using the HKF model. We identify temperature and pressure conditions at which the choice of different models can have a considerable effect on the properties of aqueous species and on fluid mineral equilibrium calculations. The investigated temperature and pressure intervals are 25–1000°C and 1–5 kbar, representative of upper to middle crustal levels, and of interest for modeling ore-forming processes. The thermodynamic and electrostatic models for water solvent considered are: Haar, Gallagher and Kell (1984), Wagner and Pruß (2002), and Zhang and Duan (2005), to calculate water volumetric properties, and Johnson and Norton (1991), Fernandez and others (1997), and Sverjensky and others (2014), to calculate water dielectric properties. We observe only small discrepancies in the calculated standard partial molal properties of aqueous species resulting from using different water thermodynamic models. However, large differences in the properties of charged species can be observed at higher temperatures (above 500°C) as a result of using different electrostatic models. Depending on the aqueous speciation and the reactions that control the chemical composition, the observed differences can vary. The discrepancy between various electrostatic models is attributed to the scarcity of experimental data at high temperatures. These discrepancies restrict the reliability of the geochemical modeling of hydrothermal and ore formation processes, and the retrieval of thermodynamic parameters from experimental data at elevated temperatures and pressures. ISSN:1468-8115 ISSN:1468-8123

The osmotic and activity coefficients of aqueous solutions of diethylammonium based protic ionic liquids (PILs) were determined experimentally using vapor pressure osmometry in the concentration range of (~0.02 to ~0.5) mol·kg−1 at 298.15 K. Osmotic coefficient data show positive deviation from Debye-Huckel limiting law for all the studied PILs. Also a minimum in osmotic coefficient data was observed at higher concentrations and is explained in terms of ion-pair formation. Data of experimental osmotic coefficient were used to obtain activities (aw) and activity coefficients (γ1) of water, mean molal activity coefficient (γ±) of PILs and excess Gibbs free energy change (ΔGE) due to mixing. Observed variations in osmotic coefficients data were explained in terms of hydrophobicity as well as H-bonding. The data of osmotic and activity coefficients were further subjected to analysis through Pitzer ion-interaction model to get an information of ion-ion and ion-solvent interaction to understand ion-pairing, ion hydration and hydrophobic effects in aqueous solutions of PILs. For this, Pitzer ion interaction parameters β(0) and β(1) were estimated and compared with literature data available for other relevant systems. Finally, the results are interpreted in terms ion-ion, ion-solvent interaction along with effect of hydrophobicity on ion-pairing and further discussed the effect of alkyl chain length of anions on solvation behavior of protic ionic liquids in aqueous solutions.

Present paper reports the results of densimetry and ultrasonic velocimetry studies of solutions of glycine, l ‑serine, l ‑proline, l ‑asparagine monohydrate and l ‑arginine in aqueous non-steroidal anti-inflammatory acetylsalicylic acid as a function of its molality. For this purpose, density and ultrasonic velocimetry data were obtained at atmospheric pressure as a function of amino acid concentration at fixed acetylsalicylic acid concentration (m = 0.001, 0.005 or 0.010 mol·kg−1) and temperature (T = 303.15, 308.15 or 313.15 K). The density and ultrasonic velocity data have been used to calculated the apparent molar volume (V2, ϕ) and apparent molar isentropic compressibility (κS, 2, ϕ) of studied solutions. The standard molar volume (V2, ϕo) and compressibility (κS, 2, ϕ0) were determined by least least-squre fitting of respective apparent properties to the amino acid molality. Further, these data were used to calculate standard transfer volume (ΔtV2, ϕo) and compressibility (ΔtκS, 2, ϕ0) of the studied solutions. The results have been interpreted in terms of different solute-solvent interactions and effect of acetylsalicylic acid on hydration of amino acids. Significant effect of added acidic cosolute drug on solute-solvent interactions including hydration of amino acids has been observed. Negative standard transfer volumes in the case of l ‑arginine in presence of drug validate the charge transfer to l ‑arginine from drug and hence enhanced electrostriction of the solvent.

Saline aquifer storage is considered to be a promising method of carbon dioxide (CO2) mitigation. The CO2–brine interfacial tension (IFT) and the caprock wettability under reservoir temperature and pressure conditions are essential for storage capacity estimation. In this study, the CO2–brine (NaCl + KCl) IFTs were obtained by using the pendant drop method under 298–373 K temperature, 3–15 MPa pressure, and 1.0–4.9 mol·kg−1 salinity. A detailed analysis of the relationship of IFT with temperature, pressure, and salinity was conducted. In addition, an empirical equation was developed to estimate the CO2–brine IFTs in a wide range of temperatures, pressures, and salt molality. The contact angles (CAs) of brine on quartz, Berea Sandstone, and limestone surfaces in the presence of supercritical, liquid, and gaseous CO2 were measured by using the sessile drop method, and the wettability alteration of the rock surfaces in the presence of supercritical CO2 was systematically investigated. According to the results, the CO2–brine IFTs increased with salinity and temperature and decreased with pressure until reaching a plateau. For a CO2–mixed brine system, a linear relationship between the IFT increase ( Δ γ ) and molality was observed. The CAs of the different rock samples varied with temperature and pressure. However, all the three rock samples became less water-wet when the CO2 phase state changed from subcritical to supercritical.

In the current work, the hyperalkaline complexation processes in the Ca2+/ d -gluconate (Gluc−) system have been studied under hypersaline conditions (I = 4 M NaCl on the molar and Im = 4.38 mol kg−1 on the molal scale, respectively) and over the temperature range of 25–75 °C by pH potentiometry using H2/Pt electrode and 13C NMR spectroscopy. The potentiometric method was validated at 75 °C. The deprotonation of the alcoholic OH− group(s) of the ligand was also investigated. Finally, the temperature dependence of the stability constants of the mono- and polynuclear complexes forming in the Ca2+/Gluc−/OH− system was determined as well. At this high ionic strength, the formation of anionic complexes seems to be facilitated by ion pair formation.

Ultrasonic is an effective tool for studying the nature and strength of molecular interactions of binary mixtures. In this present work, molecular interactions of Ammonium dihydrogen orthophosphate (ADP)electrolyte were studied using Ultrasonic method. The sound velocity is one of those physical properties that helps in understanding the nature of liquid state. Ultrasound velocity, density and viscosity of ammonium dihydrogen orthophosphate electrolyte were measured at 303 K, 308 K, 313 K,318 K and 323 K. The data obtained during the study is used for determining the various acoustical parameters like acoustic impedance, adiabatic compressibility, Rao’s constant, Wada’s constant, molar and molal salvation number, molar and molal volume, molar and molal solvated volume. Thermodynamical parameters such as internal pressure, free volume and relaxation time are also calculated. Thermodynamic properties of liquid mixtures have been extensively used to study the departure of a real liquid mixture behavior from ideality. The ultrasonic study of liquids is of immense important in understanding the biological activity of drug molecules and the activation energy of the metabolic process basically depend on the type and strength of the intermolecular interactions. Ammonium dihydrogen phosphate (ADP), also known as mono ammonium phosphate (MAP), NH4H2PO4 is often used in the blending of dry agricultural fertilizers, fire retardant for wood, paper, fabric, dispersant for fiber processing and dyeing industry, glaze for enamel, cooperating agent for fire retardant coating, decontamination agent for match stalk and candle core.

Electrolytes are the subject of a vast number of theoretical and experimental investigations concerned with a variety of modern applications. The modeling of thermodynamic properties of ionic solutions is thus a fundamental research topic that has been supported in many ways for many decades. There is however still a lack of models that are truly predictive over wide ranges of concentration, temperature and pressure conditions. In this article, the Quasi-Random Lattice (QRL) model is presented in a generalized form that allows for evaluating relevant thermodynamic properties of binary electrolyte solutions. The semi-predictive character of the model yields a powerful and competitive representation of electrolyte data over well defined concentration ranges. The additional experimental information to support the generalized version of QRL is very modest compared to the number of data points typically used in regression techniques for best-fit purposes. The thermodynamic consistency of the improved QRL model is demonstrated by the level of agreement with experimental data concerning mean activity and osmotic coefficients, apparent and partial molal volumes and enthalpies, for a variety of aqueous 1:1, 2:1, and 3:1 electrolytes.

We present fully traceable two-parameter Huckel equations with parameters B and b1 for the activity coefficient of sodium chloride and for the osmotic coefficient of water in aqueous NaCl solutions at temperatures from (353.15 to 383.15) K. In our most successful parametrization of these equations, parameter B is treated as a constant whereas b1 is a quadratic function of the temperature. The new calculations extend the tables presented up to 353.15 K in our previous study (Partanen, J. I.; Partanen, L. J.; Vahteristo, K. P. J. Chem. Eng. Data 2017, 62, 2617–2632), showing that our Huckel equations apply up to 383.15 K. We also present fully traceable activity quantities from (273.15 to 383.15) K for dilute KCl solutions. Our equations apply to these solutions at least up to a molality of 0.2 mol·kg–1. This article contains the most important new test results of the Huckel equations, where the literature data have been obtained by direct and isopiestic vapor measurements and boiling-point determinations a...

Sodium chloride (NaCl) is one of the key components of atmospheric aerosols. The surface tension of aqueous NaCl solution (σNaCl,sol) and its concentration dependence are essential to determine the equilibrium water vapor pressure of aqueous NaCl droplets. Supersaturated NaCl solution droplets are observed in laboratory experiments and under atmospheric conditions, but the experimental data for σNaCl,sol are mostly limited up to subsaturated solutions. In this study, the surface tension of aqueous NaCl is investigated by molecular dynamics (MD) simulations and the pressure tensor method from dilute to highly supersaturated solutions. We show that the linear approximation of concentration dependence of σNaCl,sol at molality scale can be extended to the supersaturated NaCl solution until a molality of ∼10.7 mol kg−1 (i.e., solute mass fraction (xNaCl) of ∼0.39). Energetic analyses show that this monotonic increase in surface tension is driven by the increase in excess surface enthalpy (ΔH) as the solution becomes concentrated. After that, the simulated σNaCl,sol remains almost unchanged until xNaCl of ∼0.47 (near the concentration upon efflorescence). The existence of the “inflection point” at xNaCl of ∼0.39 and the stable surface tension of xNaCl between ∼0.39 and ∼0.47 can be attributed to the nearly unchanged excess surface entropy term (T⋅ΔS) and the excess surface enthalpy term (ΔH). After a “second inflection point” at xNaCl of ∼0.47, the simulated σNaCl,sol gradually regains the growing momentum with a tendency to approach the surface tension of molten NaCl (∼175.58 mN m−1 at 298.15 K, MD simulation-based extrapolation). This fast increase in σNaCl,sol at xNaCl>0.47 is a process driven by excess surface enthalpy and excess surface entropy. Our results reveal different regimes of concentration dependence of the surface tension of aqueous NaCl at 298.15 K: a water-dominated regime (xNaCl from 0 to ∼0.39), a transition regime (xNaCl from ∼0.39 to ∼0.47) and a molten NaCl-dominated regime (xNaCl from ∼0.47 to 1).

The values of density and surface tension for aqueous solution of ionic liquids (ILs) 1-alkyl-3-methylimidazolium acetate [Cnmim][OAc](n = 3, 5) with various molarities were measured at 288.15–318.15 K with interval 5 K. Li’s model was improved and based on this, a new function – the molar surface Gibbs energy, gs, was derived. The gs values of the aqueous solution for ILs [Cnmim][OAc](n = 3, 5) were calculated so that a linear empirical equation between the molar surface Gibbs energy and the molality of the solution was established. Using the empirical equation, the surface tension of the solution was predicted, and the predicted values and the corresponding experimental one are highly correlated and extremely similar. Thus, the molar surface Gibbs energy may become a semi-empirical method to predict the properties of ILs and theirs solution like parachor. In terms of the molar Gibbs energy, a new Eotvos equation is obtained in which each parameter has the clearer physical meaning. According to the new Eotvos equation, the molar surface entropy is the main factor that determines the polarity of the liquid and the larger the value, the smaller the polarity of the liquid.

International audience; Binary data for the ruthenium(III) nitrosylnitrate obtained on a molality range from 0 to 18 mol kg−1 are reported. Due to the complex chemistry of this electrolyte, a combination of methods such as the simple solution concept and the Kusik-Meissner-Tester (KMT) method has been used. The necessity to use a ternary solution with the addition of nitric acid has also led to the determination of the deviation from the simple behavior of the RuNO(NO3)3/HNO3/H2O mixture. As no methodology existed prior this work to determine the binary data of an electrolyte presenting a deviation from the simple behavior when using the simple solution concept, this work brings improvements to this concept to adapt to such cases. Thus, the deviation has been estimated thanks to a mathematical approach and the Vdovenko and Ryazanov equation used for the computation of the density has been corrected to allow its use for mixtures with deviation from the simple behavior. Finally, the KMT method has been used to check if the results obtained are in accordance with what is usually observed in the literature for electrolytes.

A subduction zone plays a critical role in forging continental crust via formation of arc magmas, which are characteristically enriched in large ion lithophile elements (LILEs) and depleted in high field strength elements (HFSEs). This trace element pattern results from the different mobilities of LILEs and HFSEs during slab-to-wedge mass transfer, but the mechanisms of trace element transfer from subducting crusts are not fully understood. In this study, thermodynamic simulations are carried out to evaluate the mobilities of K and Zr, as representative cases of LILE and HFSE, respectively, in slab fluids. The fluids buffered by basaltic eclogite can dissolve &gt, 0.1 molal of K at sub-arc depths (~3 to 5.5 GPa). However, only minor amounts of K can be liberated by direct devolatilization of altered oceanic basalt, because sub-arc dehydration mainly takes place at temperatures &lt, 600 °C (talc-out), wherein the fluid solubility of K is very limited (&lt, 0.01 molal). Therefore, serpentinite-derived fluids are required to flush K from the eclogite. The solubility of K can be enhanced by the addition of NaCl to the fluid, because fluid Na+ can unlock phengite-bonded K via a complex ion exchange. Finally, it is further confirmed that Zr and other HFSEs are immobile in slab fluids.

Different metal ions as well as carbohydrates play vital role in human metabolism. The present investigation emphasizes on zinc sulphate (ZnSO4) in galactose and its comparative study with lactose in aqueous medium at 303.15, 308.15, 313.15K temperature and at 1.0 atmospheric pressure. Different physical quantities such as density, viscosity and speed of sound have been measured as function of concentrations and temperatures for these multi-component solutions. These quantities were further used to evaluate various thermo-acoustic parameters like acoustic impedance, isentropic compressibility, partial molal compressibility, partial molal volume, internal pressure etc,. The results were analyzed to assess the type and extent of association among the components. Moreover, both Zn2+ and SO42- are in the Hofmeister series and there is a possibility of ion-macro molecule interactions in aqueous solution. The breaking of the structure and the solvation of the solute by changing the temperature in mixed solvents are the point of discussion in the present study. Interestingly, the ion-solvation of zinc ion is comparatively more favorable in galactose than in lactose-water mixed solvent systems. Resumen. Diferentes iones metálicos, así como carbohidratos juegan un papel vital en el metabolismo humano. La presente investigación centra su atención sobre el sulfato de zinc (ZnSO4) en galactosa y un estudio comparativo con lactosa en soluciones acuosas a las temperaturas 303.15, 308.15, 313.15K y 1 atm de presión. Se midieron diferentes cantidades físicas como densidad, viscosidad y velocidad del sonido como función de la concentración y la temperatura de las soluciones. Posteriormente, estas cantidades se utilizaron para evaluar distintos parámetros termoacústicos como impedancia acústica, compresibilidad isoentrópica, compresibilidad molal parcial, volumen molal parcial, presión interna, etc. Los resultados se analizaron para evaluar el tipo y grado de la asociación entre los componentes. Mas aún, tanto Zn2+ como SO42- están en las series de Hofmeister y hay una posibilidad de presencia de interacciones ión-macromolécula en la solución acuosa. Un punto de discusión en el presente estudio es el rompimiento de la estructura y la solvatación del soluto debidos al cambio de la temperatura de las soluciones. Es interesante hacer notar que la solvatación de los iones de zinc es comparativamente mas favorable en las soluciones acuosas de galactosa que de lactosa.

This work is aimed at improving a mathematical multiphase flow model in the antroduodenum, developed previously. Based on the experimental data found in the literature, several main theses concerning viscosity of monosaccharides and disaccharides are formulated: the concentration dependence of the viscosity can be considered linear at low carbohydrates concentrations (

The pH of CO2-saturated brines is of importance in geological carbon storage utilizing saline aquifers as it is a key variable controlling fluid-mineral chemical reactions that affect CO2 storage capacity and security. In this paper, we report experimental measurements of the pH of CO2-saturated aqueous KCl solutions carried out using high-pressure glass and ZrO2 pH electrodes, coupled with a Ag/AgCl reference electrode, at a temperatures from (298 to 423 K) and at pressure between (0.2 and 13.5) MPa. The results are in good agreement with values predicted using the Pitzer model with the McInnes convention as implemented in the PHREEQC geochemical simulator software. The pH of CO2-saturated KCl solutions decreases with increasing partial pressure of CO2 and increases with increasing temperature. Increasing the molality of the KCl solutions tends to lower the pH but not as rapidly as is the case the NaCl.

Densities the ternary system (CaCl2-SrCl2-H2O) and its binary sub-systems (CaCl2-H2O and SrCl2-H2O) were elaborately measured with an Anton Paar Digital vibrating-tube densimeter at temperature intervals of 5 K from 278.15 K to 323.15 K. The coefficient of thermal expansion (α) and apparent mole volume ( φ V ) for the binary systems were obtained based on the experimental density results. Apparent mole volumes of CaCl2 and SrCl2 varied smoothly with solute molality and could be fitted using an extended RRM equation. Based on the PK method, the density for the ternary system was predicted by the density of the two binary sub-systems, and there is a good consistency between the results of predicted and experimental. On the basis of volumetric property data for the binary and ternary systems, the Pitzer single-salt parameters ( β MX ( 0 ) V , β MX ( 1 ) V and C MX V , MX = CaCl2 and SrCl2) and mixing ion-interaction parameters θ Ca,Sr V , ψ Ca,Sr,Cl V ) were parameterized according to Pitzer ion-interaction theory of single salt electrolyte and mixture electrolytes, respectively. Volumetric property was analysed using the Pitzer model and the predicted values were comparable with experimental values. The simulation results indicate that the Pitzer model parameters can reliably represent the properties of the systems. The temperature-dependence equations and the temperature correlation coefficients for those parameters were also obtained. The volume properties of three systems can be quantitatively obtained according to the electrolyte parameterization model within the experimental temperature range.

In this work, for further study on solubility behaviors of calcium sulfate dihydrate (DH) in different organic aqueous solutions, solubility of calcium sulfate dihydrate (DH) in three binary solvents (water + ethylene glycol, acetic acid, dimethyl sulfoxide) was experimentally investigated by the dissolution equilibrium method at (303.15 to 348.15) K under 88.35 kPa. Solubility data of DH first increased and then decreased with the temperature increased while reduced with the increasing molality of organic solvents. Experimental solubility data was correlated by four thermodynamic models including Wilson, modified Apelblat-Jouyban-Acree, UNIQUAC and NRTL model, all of them can well correlate the solubility of DH. Besides, thermodynamic properties of mixing process (ΔmixG, ΔmixS, ΔmixH, H1E,∞ and lnγ1∞) were investigated based on solubility data and the Wilson equation.