Excess molar volumes of formic acid + water acetic acid + water and propionic acid + water systems at 288.15, 298.15 and 308.15 K

Densities and excess molar volumes were determined in the formic acid + water, acetic acid + water and propionic acid + water systems at 288.15, 298.15 and 308.15 K. The results are satisfactorily described using the ideal association model of the type A + B + A₂ for the system with formic acid. The Mecke—Kempter model is adequate for the acetic acid + water and propionic acid + water systems. In both models the formation of open dimers and open higher associates is postulated for the self-association of carboxylic acids in water.     

Excess molar volumes for ternary mixture (N,N-dimethylformamide+1-propanol+water) at the temperature 298.15 K

The results of excess molar volumes for ternary mixture N,N-dimethylformamide (DMF)+1-propanol+water and for binary constituents, DMF+water, DMF+1-propanol and 1-propanol+water at 298.15 K are reported. Several empirical expressions were used to predict and correlate the ternary excess molar volumes from experimental results on the constituent binaries. A pseudo-binary mixture approach (PBMA) was used to analyze the system studied. The partial molar volumes of 1-propanol at infinite dilution in [f_mDMF+(1−f_m)water] mixed solvents at their several fixed composition f_m were evaluated and correlated with the composition f_m.     

Measurement and correlation of excess molar enthalpies for the partially miscible systems 2-butanone+water and methanol+hexane

The excess molar enthalpies of the systems 2-butanone+water and methanol+hexane which show limited miscibility were measured at 283.15–298.15 K using a flow microcalorimeter. The experimental data were correlated using three local-composition (LC) models (NRTL, modified Wilson and modified EBLCM). These models were also used to predict the liquid–liquid equilibria for both systems with the parameters obtained from the excess enthalpy data.     

Thermodynamic properties of the ethylammonium nitrate + water system: Partial molar volumes,heat capacities,and expansivities

Partial molar volumes at 15, 25, and 45°C and partial molar heat capacities and expansivities at 25°C for ethylammonium nitrate + water mixtures are reported. The results are compared with those for other aqueous cosolvents, particularly hydrazine and ammonium nitrate.     

Apparent molar volumes of lithium nitrate in 1-propanol + water in the temperature range from 288.15 to 318.15 K

Densities of 1-propanol+water+lithium nitrate mixtures have been measured with an oscillating-tube densimeter over a large range of concentrations of the salt and 1-propanol, at 288.15, 298.15, 308.15, and 318.15 K. From these densities, apparent molar volumes of lithium nitrate in 1-propanol+water mixtures have been calculated for each temperature, and apparent molar volumes at infinite dilution have been evaluated. An empirical correlation for partial molar volumes of lithium nitrate in 1-propanol+water mixtures with solvent composition and temperature has been derived.     

Excess molar volumes and molar refraction of 1,3-dimethyl-3,4,5,6-tetrahydro-2(1H)-pyrimidinone+water water from 5 to 45°C

The excess molar volumes and molar refractionsR ₁₂ of 1,3-dimethyl-3,4,5,6-tetrahydro-2(1H)-pyrimidinone (DMPU)+water have been determined over the entire mole fraction range at 10° intervals from 5 to 45°C and at atmosphere pressure. The excess volumes are all negative and they become more positive with increase of temperature. Limiting partial molar volumes for DMPU in water and water in DMPU are also reported.     

Partial molar volumes of monovalent ions in ethanolamine and water + ethanolamine mixtures at 25°C

Precise densities for sodium of chloride, bromide and iodide and potassium iodide in ethanolamine and water+ethanolamine mixtures (15, 30, 50, 60, 70, 80 and 90 mass% ethanolamine) up to a maximum salt molality of 0.15 mol-kg⁻¹ are reported from measurements at 25°C using a vibrating tube densimeter. The electrolyte apparent molar volumes were calculated and extrapolated to infinite dilution using the Masson equation to yield the limiting electrolyte partial molar volumes. The limiting ionic partial molar volumes V _ion ^o were estimated using Mukerjee's method. A correspondence principle proposed earlier for predicting ionic entropies could be used for the estimation of V _ion ^o for rubidium and cesium salts. The estimates of the contributions from geometric and the electrostrictive effects to V _ion ^o are also reported. The variations in these contributions with the change in solvent composition are discussed in terms of the changes in the solvent structure.     

Dew points of binary carbon dioxide + water and ternary carbon dioxide + water + methanol mixtures: Measurement and modelling

Dew points for four carbon dioxide + water mixtures between 1.2×10⁵ and 41.1×10⁵ Pa in the temperature range from 251.9 to 288.2 K, and eight carbon dioxide + water + methanol mixtures between 1.2×10⁵ and 43.5×10⁵ Pa and temperatures from 246.0 to 289.0 K were experimentally determined. The experimental results obtained on the binary and ternary systems were analysed in terms of a predictive excess function–equation of state (EF–EOS) method, which reproduced the experimental dew point temperature data with absolute average deviation (AAD) between 0.8 and 1.8 K for the systems with water, and from 0.0 to 2.7 K for the systems with water and methanol. The experimental results obtained for carbon dioxide + water mixtures, with molar fraction of water lower than 0.00174, at pressure values higher than 5×10⁵ Pa were also compared to a predictive equation of state model. It reproduced experimental dew point temperature data with AAD between 0.2 and 0.6 K.     

Thermodynamics of silver salicylate in water and water + 10, + 20, and + 40 mass percent of dioxane at different temperatures

The solubility studies on silver salicylate at different temperatures were made to derive (a) the standard electrode potential of the silver—silver salicylate electrode, (b) the mean activity coefficient of silver salicylate, (c) the dissociation constant of salicylic acid, and (d) the standard thermodynamic quantities, ΔG⁰_t, ΔH⁰_t, ΔS⁰_t, and δC⁰_pt, for the transfer of silver salicylate from the standard state in water to the standard state in water + 10, + 20, and + 40 mass percent of dioxane. The results are discussed in terms of the preferential solvation of the ions.     

Viscosity Arrhenius activation energy and derived partial molar properties in N,N-Dimethylacetamide + water binary mixtures at temperatures from 298.15 to 318.15 K

Calculation of excess properties in N,N-dimethylacetamide + water binary mixtures at (298.15, 308.15 and 318.15) K from experimental density, viscosity and sound velocity values were presented in previous work. Applications of these experimental values to test different correlation equations as well as their corresponding relative functions were also reported. Considering the quasi-equality between the Arrhenius activation energy Ea and the enthalpy of activation of viscous flow ΔH*, here we can define partial molar activation energy Ea ₁ and Ea ₂ for N,N-dimethylacetamide and water respectively along with their individual contribution separately. Correlation between the two Arrhenius parameters of viscosity in all the domains of composition shows the existence of two main distinct behaviours separated by a stabilised structure in a short range of mole fraction in N,N-dimethylacetamide from 0.2 to 0.3. We add that correlation reveals interesting Arrhenius temperature which is closely related to the vapourisation temperature in the liquid vapour equilibrium.     

Gamma irradiation-induced Cd2+ and Pb2+ removal from different kinds of water

Gamma irradiation-induced removal of cadmium ion (Cd²⁺) and lead ion (Pb²⁺) in different kinds of water was investigated. It is observed that solution pH, dissolved oxygen (DO) concentration, sodium carbonate and EDTA played an important effect on Cd²⁺ and Pb²⁺ removal. Low solution pH, low DO concentration and sodium carbonate were favorable for removal of Cd²⁺ and Pb²⁺ by reducing species, while the presence of EDTA in solution restrained Cd²⁺ and Pb²⁺ reduction. Pb²⁺ removal percentage was higher compared to that of Cd²⁺ at the same experimental conditions. Cd²⁺ and Pb²⁺ removal under different conditions was well described by the pseudo-first-order kinetics model. Cd²⁺ and Pb²⁺ removal in different water followed an increasing order: water inflow<surface water<effluent<ground water. In addition, gamma irradiation resulted in a slight decrease in pH and TOC values of water inflow of municipal sewage treatment plant.     

Partial molar volumes of amino acid derivatives in water

The partial molar volumes at infinite dilution for a number of hydrochlorides and sodium salts of N-methyl derivatives of , -aminocarboxylic acids in water at 25°C are measured and related to their van der Waals volumes. Results indicate that 4.96±0.48 water molecules hydrate a betaine hydrochloride. Volumes of proton ionization and interaction terms are evaluated. Group contributions to the partial molar volumes are also reported.     

Binodal curve of two liquid phases and solid-liquid equilibrium for water + fatty acid + ethanol systems and water + fatty acid + acetone systems

To determine the liquid-liquid-solid three-phase equilibrium (LLSE), binodal data of the liquid-liquid equilibrium (LLE) and the solid-liquid equilibrium (SLE) have been measured for the ternary water + acetone or ethanol + lauric acid, myristic acid or palmitic acid systems. The binodal region for two liquid phases increases successively in the following order of the third component: lauric acid < myristic acid < palmitic acid. The binodal regions of the ternary systems with acetone as the second component are larger than those for ethanol. These binodal curves are not highly sensitive to temperature. The isothermal solubility of these fatty acids is considerably reduced when the water content in the aqueous phase increases. The solubility of fatty acids is successively reduced in the following order: lauric acid > myristic acid > palmitic acid. The solubility of fatty acids in aqueous solutions containing acetone is smaller than in those containing ethanol. Predictions of both the binodal curve for LLE and the SLE curve by the UNIFAC method and the NRTL equation do not represent the experimental data. However, data of the binodal curve and solubility are well correlated by the NRTL equation, and also the LLSE relationship could be represented.     

Fabrication of high Li:water molar ratio electrolytes for lithium-ion batteries

Hydrous electrolytes with high electrochemical potentials were obtained by hydrating water molecules into solutes to form high Li:water molar ratio electrolytes(HMRE).Solid polyethylene glycol(PEG) were e mployed to enha nce the molar ratio of Li+to water in the electrolytes while reducing the consumption of Li-salt.The obtained mole ratio of Li~+ to wa ter molecules in the hydrous electrolytes was greater than 1:1;however,the mass fraction of Li-salt was reduced to 61%(approximately 5.5 mol/kg,based on water and PEG).Compared with that of water-in-salt electrolytes,the mass fraction of Li-salt could be remarkably reduced by adding solid PEG.The electrochemical stability of the electrolytes improved considerably because of the strong hydration of Li~+ by the water molecules.A beneficial passivation effect,arising from the decomposition of the electrolyte,at a wide potential window was observed.     

Luminescence properties and water coordination of Eu3+ in the binary solvent mixture water/1-butyl-3-methylimidazolium chloride

The effect of relative water content on the luminescence properties and speciation of Eu3+ ions in solutions of EuCl3 in the binary solvent mixture water/[BMI]Cl is presented, where [BMI]Cl is the ionic liquid (IL) 1-butyl-3-methylimidazolium chloride. Using luminescence techniques, the binding properties of water to Eu3+ are determined for samples with mole ratios of water-to-IL ranging from 0 to 5. Very little water binds to Eu3+ at mole ratios of water-to-IL less than 1, above which binding increases rapidly with increasing water concentration. It is shown that only certain hydration numbers for Eu3+ complexes are stable in the water/IL solutions. The data presented suggest that the Eu3+ species present are [EuClx]3-x, [EuCly(H2O)3-4]3-y, [EuClz(H2O)6]3-z, and [Eu(H2O)8-9]3+ (where x > y > z). Comparison of the positions of the 5D0<--7F0 transitions of the Eu3+ complexes in IL solution with those of model crystal systems provides insight into the extent of Cl- complexation. This study suggests that [BMI]Cl is a promising medium for luminescent lanthanide (Ln) compounds due to the low-energy phonon environment of the [LnClx]3-x complex and to the fact that moderate water contamination does not result in direct binding of water to Ln3+, which would result in luminescence quenching.     

Volumetric properties of the (tetrahydrofuran + water) and (tetra-n-butyl ammonium bromide + water) systems: Experimental measurements and correlations

In this communication, we report experimental density data for the binary mixtures of (water + tetrahydrofuran) and (water + tetra-n-butyl ammonium bromide) at atmospheric pressure and various temperatures. The densities were measured using an Anton Paar™ digital vibrating-tube densimeter. For the (tetrahydrofuran + water) system, excess molar volumes have been calculated using the experimental densities and correlated using the Redlich–Kister equation. The Redlich–Kister equation parameters have been adjusted on experimental results. The partial molar volumes and partial excess molar volumes at infinite dilution have also been calculated for each component. A simple density equation was finally applied to correlate the measured density of the (tetra-n-butyl ammonium bromide + water) system.     

Phase behaviour of ethanol + water + ethyl acetate at 101.3 kPa

Must distillation processes simulation is a challenging task, due to the lack of thermodynamic interaction parameters and accurate studies of phase equilibria. The presence of polar substances, those different from ethanol and water, and their low concentrations make it very difficult to model industrial distillation. Several of the congeners are essential enological components of the organoleptic matrix. In this work, we are concerned with the study of phase behaviour of ethanol + water + ethyl acetate at 101.3 kPa, this being the third compound, the legal congener of the highest composition in common alcoholic distillation. The experimental results showed partial miscibility and four azeotropes into a complex medium. Group contribution models yield poor results. Disposable literature was compared and commented upon. The lack of experimental data in multicomponent alcoholic distillation mixtures and the low reliability of the group contribution methods suggest a prudent application to process simulation.     

Excess molar volumes of methylcyclohexane+benzene, +methylbenzene, +1,4-dioxane,and +tetrahydrofuran at 303.15 K

Excess molar volumes V_m^E as function of mole fraction x for methylcyclohexane + benzene, + methylbenzene, + 1,4-dioxane, and + tetrahydrofuran are reported at 303.15 K. The excess molar volumes are positive and indicate the presence of weak interactions.     

Liquid—liquid equilibria for the system water + acetic acid + methyl isoamyl ketone

Liquid—liquid equilibrium data obtained over the temperature range 10–60°C for the binary system water + methyl isoamyl ketone (MIAK) are presented together with ternary data for the system water + acetic acid + MIAK at 15, 25 and 40°C. The latter system may be of particular interest for solvent extraction studies, in that MIAK has a flash point much higher than that of methyl isobutyl ketone (MIBK). The new data presented in this paper are correlated in terms of the well-known NRTL and UNIQUAC models. Using the UNIFAC model and the parameter table published recently, experimental results are compared with the predicted values.