Study of densities,viscosities, and speeds of sound of binary liquid mixtures of butan-1-ol with n-alkanes (C6, C8, and C10) at T = (298.15, 303.15, and 308.15) K

The densities (ρ) and speeds of sound (u) have been measured over the whole composition range for (butan-1-ol with hexane, or octane, or decane) at T = (298.15, 303.15, and 308.15) K and atmospheric pressure along with the properties of the pure components. Viscosities (η) of these binary mixtures have also been measured over the entire composition range at T = 298.15 K. Experimental values of density, viscosity and speed of sound have been used to evaluate excess properties viz. excess molar volumes (V^E), deviation in viscosity (Δη), deviation in speeds of sound (Δu), deviation in isentropic compressibility (Δκ_s) and excess Gibbs free energy of activation of viscous flow (ΔG^1E). The excess properties have been correlated using the Redlich–Kister polynomial equation. The sign and magnitude of these excess properties have been used to interpret the results in terms of intermolecular interactions and structural effects. The viscosity data have also been correlated by Grunberg and Nissan, Tamura–Kurata, and Hind correlation equations.     

Solubility of gallic acid in liquid mixtures of (ethanol + water) from (293.15 to 318.15) K

The solubility of gallic acid in (water + ethanol) binary solvents was determined from (293.15 to 318.15) K at atmospheric pressure using a thermostatted reactor and UV/vis spectrophotometer analysis. The effects of binary solvents composition and temperature on the solubility were discussed. It was found that gallic acid solubility in (water + ethanol) mixed solvents presents a maximum-solubility effect. Two empirical equations were proposed to correlate the solubility data. The calculated solubilities show good agreement with the experimental data within the studied temperature range. Using the experimentally measured solubilities, the thermodynamic properties of dissolution of the gallic acid such as Gibbs energy (Δ_solG°), molar enthalpy of dissolution (Δ_solH°), and molar entropy of dissolution (Δ_solS°) were calculated.     

Experimental excess molar properties of binary mixtures of (3-amino-1-propanol + isobutanol, 2-propanol) at T = (293.15 to 333.15) K and modelling the excess molar volume by Prigogine–Flory–Patterson theory

Density and viscosity of binary mixtures of (x₁3-amino-1-propanol + x₂isobutanol) and (x₁3-amino-1-propanol + x₂2-propanol) were measured over the entire composition range and from temperatures (293.15 to 333.15) K at ambient pressure. The excess molar volumes and viscosity deviations were calculated and correlated by the Redlich–Kister (RK) equation. The thermal expansion coefficient and its excess value, isothermal coefficient of excess molar enthalpy, and excess partial molar volumes were determined by using the experimental values of density and are described as a function of composition and temperature. The excess molar volumes are negative over the entire mole fraction range for both mixtures and increase with increasing temperature. The excess molar volumes obtained were correlated by the Prigogine–Flory–Patterson (PFP) model. The viscosity deviations of the binary mixtures are negative over the entire composition range and decrease with increasing temperature.     

(Vapor + liquid) phase equilibrium measurements for {trifluoroiodomethane (R13I1) + propane (R290)} from T = (258.150 to 283.150) K

In this paper, the (vapor + liquid) equilibrium data for (R13I1 + R290) were measured by a vapor-recirculation apparatus at temperatures from (258.150 to 283.150) K. The VLE data were correlated by the Peng–Robinson equation of state with two different models, the van der Waals mixing rule, and the Huron–Vidal mixing rule involving the NRTL activity coefficient model. Good agreements were found between the calculated data and the experimental data. The maximum average absolute relative deviation of pressure (AARD p) was 0.48%, while the maximum average absolute deviation of composition (AAD y) was 0.0040. Meanwhile, zeotropic behavior can be found for the measured system in this study. The total combined standard uncertainties for temperature, pressure and composition measurements were ±5 mK, ±0.0005 MPa and ±0.005, respectively.     

Isothermal compressibility and internal pressure studies of some non-electrolytes in aqueous solutions at low temperatures

The experimental data of density (ρ) and sound velocity (u) in the temperature range (275.15 to 293.15) K have been obtained for the systems (dioxane + water), (dimethylformamide + water), (tetrahydrofuran + water), and (acetonitrile + water). The specific heat (C_p) data for the above systems have been obtained at T = 279.15 K. The data obtained are used to calculate the derived parameters of adiabatic compressibility (β_S), at T = 275.15 K to T = 283.15 K, isothermal compressibility (β_T), and internal pressure (P_i) at T = 279.15 K for different concentrations. The solute properties: apparent molar volume (ϕ_V), apparent molar expansivity (ϕ_E), and apparent molar compressibility (ϕ_KS) have been studied and the limiting values for these properties are reported. The variation in apparent molar properties with concentration and the corresponding temperature and pressure effects are discussed in terms of hydrophobic hydration (–H bonding interaction) and hydrophobic interaction (non-polar group solute–solute association in water). It is noted that the internal pressure of solutions is quite insensitive in the region of solute–solute association, while its variation with concentration in the dilute region is sensitive in contrast to the aqueous alcohol solutions. The molecular interactions also exhibit individualistic behaviour and are much dependent on structural alterations in water structure.     

Effect of the temperature on the physical properties of pure 1-propyl 3-methylimidazolium bis(trifluoromethylsulfonyl)imide and characterization of its binary mixtures with alcohols

In this paper, physical properties of a high purity sample of the ionic liquid 1-propyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [PMim][NTf₂], and its binary mixtures with methanol, ethanol, 1-propanol, and 2-propanol were measured at atmospheric pressure. The temperature dependence of density, refractive index and speed of sound (293.15 to 343.15) K and dynamic viscosity (298.15 to 343.15) K were studied at atmospheric pressure by conventional techniques for the pure ionic liquid. For its mixtures with alcohols, density, speed of sound, and refractive index were measured at T = 298.15 K over the whole composition range. The thermal expansion coefficient of the [PMim][NTf₂] was calculated from the experimental results using an empirical equation, and values of the excess molar volume, excess refractive index, and excess molar isentropic compressibility for the binary systems at the above mentioned temperature, were calculated and fitted to the Redlich–Kister equation. The heat capacity of the pure ionic liquid at T = 298.15 K was determined using DSC.     

Solubility of perfumery and fragrance raw materials based on cyclohexane in 1-octanol under ambient and high pressures up to 900 MPa

The (solid + liquid) phase equilibria (SLE) of binary mixtures containing 1-octanol and fragrance raw materials based on cyclohexane were investigated. The systems {1-octanol (1) + cyclohexyl carboxylic acid (CCA), or cyclohexyl acetic acid (CAA), or cyclohexyl acetate (CA), or 2-cyclohexyl ethyl acetate (2CEA), or 2-cyclohexyl ethanol (2CE)(2)} have been measured by a dynamic method in wide range of temperatures from (220 to 320) K and ambient pressure. For all systems SLE diagrams were detected as eutectic mixtures with complete miscibility in the liquid phase. The experimental data were correlated by means of the Wilson and NRTL equations, utilizing parameters derived from the (solid + liquid) equilibrium. The root-mean-square deviations of the solubility temperatures for all calculated data are dependent upon the particular system and the particular equation used.Additionally, the SLE in binary mixture that contain {1-octanol (1) + CCA (2)} has been measured under very high pressures up to about 900 MPa at the temperature range from T = (303.15 to 353.15) K. The thermostatted apparatus for the measurements of transition pressures from the (liquid + solid) state was used. The freezing and melting temperatures at a constant composition increase monotonously with pressure. The high pressure experimental results obtained at isothermal conditions (p–x) were interpolated to more convenient T–x diagram. Data of the (pressure + temperature) composition relation at the high pressure (solid + liquid) phase equilibria was correlated by the polynomial based on the Yang model.The basic thermodynamic properties of pure substances viz. the melting point, enthalpy of fusion, enthalpy of solid–solid phase transition, and glass transition, have been determined by the differential scanning calorimetry (DSC).     

Volumetric and viscosimetric properties of N-methyl-2-pyrrolidone with γ-butyrolactone and propylene carbonate

Volumetric properties of N-methyl-2-pyrrolidone (NMP) binary mixtures with γ-butyrolactone (GBL) and propylene carbonate (PC) are calculated from the experimental densities and reported in the temperature range from (293.15 to 323.15) K and at atmospheric pressure (0.1 MPa) over the whole composition range. The excess molar volumes have positive values in the whole concentration range in the case of (NMP + PC) binary mixture, with maximum value at equimolar composition, indicating weaker interactions between the components after the mixing. Two extreme V^E values are observed in (NMP + GBL) system: maximum at x(NMP) = 0.4 and minimum at x(NMP) = 0.9. Negative V^E values in NMP-rich region are the consequence of the better geometrical fit of the molecules. The excess properties of (NMP + GBL) and (NMP + PC) binaries are analyzed using Prigogine–Flory–Paterson theoretical model. An excellent agreement between experimental and theoretical values at equimolar composition is observed. Apparent molar volumes and thermal expansion coefficients are also calculated. Viscosity measurements of the pure components and NMP binary mixtures with GBL and PC were performed in the temperature range from (298.15 to 323.15) K. Using obtained experimental viscosities several semi-empirical equations and models were tested.     

Effect of temperature on the physical properties of 1-butyl-3-methylimidazolium based ionic liquids with thiocyanate and tetrafluoroborate anions,and 1-hexyl-3-methylimidazolium with tetrafluoroborate and hexafluorophosphate anions

The effect of temperature on the physical properties of some ionic liquids was investigated. Density, refractive index, surface tension, dynamic and kinematic viscosities of 1-butyl-3-methylimidazolium based ionic liquids with thiocyanate and tetrafluoroborate, and 1-hexyl-3-methylimidazolium with tetrafluoroborate and hexafluorophosphate anions were measured at various temperatures (density from T = (278.15 to 363.15) K, refractive index from (293.15 to 343.15) K, surface tension from (283.15 to 333.15) K, dynamic viscosity from (283.15 to 368.15) K, and kinematic viscosity from (298.15 to 363.15) K). The volumetric properties for the ionic liquids were also calculated from the experimental values of the density at T = 298.15 K. The Vogel–Fulcher–Tammann (VFT) equation was applied to correlate experimental values of dynamic and kinematic viscosities as a function of temperature. As well, the relation between density and refractive index was correlated satisfactorily with several empirical equations such as Lorentz–Lorenz, Dale–Gladstone, Eykman, Oster, Arago–Biot, Newton and Modified–Eykman. Finally, the relation between surface tension and viscosity was investigated and the parachor method was used to predict density, refractive index and surface tension of the ionic liquids.     

Experimental measurement and modelling of KBr solubility in water,methanol, ethanol,and its binary mixed solvents at different temperatures

A simple and accurate apparatus has been designed to measure the solubilities of potassium bromide by an analytical method. Salt solubility data have been measured in water, methanol, ethanol, (water  +  methanol), (water  +  ethanol), and (methanol  +  ethanol) solvents in the temperature range between 298.15 K and 353.15 K.A new formulation is presented for the calculation of salt solubility in pure and mixed solvents as a function of the temperature and solvent composition. This formulation is based on the symmetric convention for the normalization of the activity coefficients for all species in solution, and makes possible direct access to the solubility product of the salt in terms of its thermodynamic properties. The new solubility data measured in this work, as well as experimental information from the open literature, are used to estimate the interaction parameters of the two models proposed here. One model combines the original Universal Quasi Chemical (UNIQUAC) equation with a Pitzer–Debye–Hückel expression to take into account the long-range interaction forces; the other model only considers the short-range forces through the UNIQUAC equation with linear temperature dependent salt/solvent interaction parameters. Both models correlate satisfactorily the solubility data, although temperature and electrostatic effects are both very important in this type of equilibrium. Finally, some conclusions are drawn concerning the models versatility to represent other type of equilibrium data and prediction capabilities.     

Novel 1D coordination polymer {Tm(Piv)3}n: Synthesis,structure, magnetic properties and thermal behavior

The new 1D coordination polymer {Tm(Piv)₃}_n (1), where Piv=OOCBu^t?, was synthesized in high yield (>95%) by the reaction of thulium acetate with pivalic acid in air at 100 °С. According to the X-ray diffraction data, the metal atoms in compound 1 are in an octahedral ligand environment unusual for lanthanides. The magnetic and luminescence properties of polymer 1, it’s the solid-phase thermal decomposition in air and under argon, and the thermal behavior in the temperature range of ?50…+50 °С were investigated. The vaporization process of complex 1 was studied by the Knudsen effusion method combined with mass-spectrometric analysis of the gas-phase composition in the temperature range of 570–680 K.     

Effect of alkyl chain length and temperature on the thermodynamic properties of ionic liquids 1-alkyl-3-methylimidazolium bromide in aqueous and non-aqueous solutions at different temperatures

The alkyl chain length of 1-alkyl-3-methylimidazolium bromide ([Rmim][Br], R = propyl (C₃), hexyl (C₆), heptyl (C₇), and octyl (C₈)) was varied to prepare a series of room-temperature ionic liquids (RTILs), and experimental measurements of density and speed of sound at different temperatures ranging from (288.15 to 308.15) K for their aqueous and methanolic solutions in the dilute concentration region (0.01 to 0.30) mol · kg^?1 were taken. The values of the compressibilities, expansivity and apparent molar properties for [C_nmim][Br] in aqueous and methanolic solutions were determined at the investigated temperatures. The obtained apparent molar volumes and apparent molar isentropic compressibilities were fitted to the Redlich–Mayer and the Pitzer’s equations from which the corresponding infinite dilution molar properties were obtained. The values of the infinite dilution molar properties were used to obtain some information about solute–solvent and solute–solute interactions. The thermodynamic properties of investigated ionic liquids in aqueous solutions have been compared with those in methanolic solutions. Also, the comparison between thermodynamic properties of investigated solutions and those of electrolyte solutions, polymer solutions, cationic surfactant solutions and tetraalkylammonium salt solutions have been made.     

Viscosities and refractive indices of binary mixtures of 1-butyl-3-methylimidazolium tetrafluoroborate and 1-butyl-2,3-dimethylimidazolium tetrafluoroborate with water at 298 K

Viscosities and refractive indices have been determined for (water + 1-butyl-3-methylimidazolium tetrafluoroborate) and (water + 1-butyl-2,3-dimethylimidazolium tetrafluoroborate) mixtures at 298.15 K, over the whole composition range. The refractive indices were compared with the predictions of the Lorentz–Lorenz, Wiener, and Gladstone–Dale equations. Viscosity deviations (Δη) and refractive index deviations (Δn_D) have been calculated and fitted to the Redlich–Kister polynomial equations. Δn_D are positive whereas Δη are negative over the entire mixture composition for the two salts. The influence of the structure of imidazolium cation on the above physicochemical properties was discussed.     

Physical properties of 3-methyl-N-butylpyridinium tetracyanoborate and 1-butyl-1-methylpyrrolidinium tetracyanoborate and ternary LLE data of [3-mebupy]B(CN)4 with an aromatic and an aliphatic hydrocarbon at T = 303.2 K and 328.2 K and p = 0.1 MPa

Several physical properties were determined for the ionic liquids 3-methyl-N-butylpyridinium tetracyanoborate ([3-mebupy]B(CN)₄) and 1-butyl-1-methylpyrrolidinium tetracyanoborate ([1-mebupyr]B(CN)₄), viz. liquid density, viscosity, surface tension, thermal stability, and heat capacity over the temperature range from 283.2 K to 475.2 K and at 0.1 MPa. The density and the surface tension were well correlated with linear equations and the viscosity with a Vogel–Fulcher–Tamman equation. The IL [3-mebupy]B(CN)₄ is stable up to a temperature of 480 K and the IL [1-mebupyr]B(CN)₄ up to a temperature of 548 K.Ternary data for the systems {(benzene + n-hexane), or (toluene + n-heptane), or (p-xylene + n-octane + [3-mebupy]B(CN)₄)} were determined at T = 303.2 K and 328.2 K and p = 0.1 MPa. All experimental data were well correlated with the NRTL model. The values of the experimental and calculated aromatic/aliphatic selectivity are in good agreement with each other. The LLE data of [1-mebupyr]B(CN)₄ were only measured in a 10 vol% aromatic feed for the three systems.     

Temperature and pressure dependences of volumetric properties of two poly(propylene glycol) dimethyl ether lubricants

The densities at high pressures of two dimethoxy end-capped poly(propylene glycols), CH₃–O–[CH₂–CH(CH₃)–O]_m–CH₃, with average molar masses higher than 1300 g · mol^?1, were measured in the range (0.1 to 60) MPa at five different temperatures from (298.15 to 398.15) K. The measurements were performed in a high-pressure vibrating tube densimeter. A correction factor, due to the viscosity of the sample, was applied to the experimental density values. The pressure–volume–temperature behavior of these lubricants was evaluated accurately over wide temperature and pressure ranges and correlated successfully with the empirical Tammann–Tait equation. The experimental data and the correlations were used to study the behavior and the influence of temperature and pressure on the isothermal compressibility, the isobaric thermal expansivity, and the internal pressure, as well as the effect of the polyether molecular structure on these properties.     

Molar heat capacities of some aqueous (2-amino-2-hydroxymethyl-1,3-propanediol + glycol) systems

A new set of molar heat capacity data for aqueous {2-amino-2-hydroxymethyl-1,3-propanediol (TRIS) + glycol} at (30 to 80) °C and different concentrations (4% to 16% by weight TRIS or 56% to 44% by weight water, in a fixed amount of glycol – 40% by weight) were gathered via reliable measurement method and are presented in this report. The glycols considered were diethylene glycol (DEG), triethylene glycol (TEG), tetraethylene glycol (T₄EG), propylene glycol (PG), dipropylene glycol (DPG), and tripropylene glycol (TPG). The 198 data points gathered fit the equation, C_p = C_p,a + B₁m + B₂m² + B₃m³, where C_p and C_p,a are the molar heat capacities of the (TRIS + glycol + water) and (water + glycol) systems, respectively, B_i the temperature-dependent parameters, and m the mole TRIS per kilogram (glycol + water). The overall average absolute deviation (AAD) of the experimental data from the corresponding values calculated from the correlation equation was 0.07%.     

Liquid–liquid equilibrium data of water with neohexane,methylcyclohexane, tert-butyl methyl ether,n-heptane and vapor–liquid–liquid equilibrium with methane

Liquid–liquid equilibrium (LLE) data for non-aqueous liquid (neohexane [NH], tert-butyl methyl ether [TBME], methylcyclohexane [MCH], or n-heptane [nC₇]) and water have been measured under atmospheric pressure at 275.5, 283.15, and 298.15 K. It was found that TBME is the most water soluble followed by NH, MCH, and nC₇. As the temperature increased, the solubility of the non-aqueous liquids (NALs) in water decreased. The solubility of water in the non-aqueous liquid was found to increase in the following order: MCH < nC₇ < NH < TBME. It was found to increase with increasing temperature. In addition, vapour–liquid–liquid equilibrium (VLLE) data for the above binary systems with methane were measured at 275.5 K and at 120, 1000, and 2000 kPa. It was found that the vapour composition of water and NALs decreased as the pressure increased. The water content in the non-aqueous phase was not a strong function of pressure. The concentration of methane in the non-aqueous phase increased as the pressure increased. Furthermore, the concentration of the methane and NALs in the water phase increased proportionally with pressure. The solubility of methane in water followed Henry's law. It is noted that the measurements were completed prior to the onset of hydrate nucleation.     

(Vapour + liquid) equilibrium data for the azeotropic {1,1-difluoroethane (R152a) + 1,1,2,2-Tetrafluoroethane (R134)} system at various temperatures from (258.150 to 288.150) K

(Vapour + liquid) equilibrium (VLE) data for the {1,1-difluoroethane (R152a) + 1,1,2,2-Tetrafluoroethane (R134)} system were measured at T = (258.150 to 288.150) K. The experiment is based on a static–analytic method. Experimental data were correlated with the Peng–Robinson equation of state (PR EoS) and the Huron–Vidal (HV) mixing rule involving the NRTL activity coefficient model. The results show good agreement with experimental results for the binary system at each temperature. It was found that the system has a negative azeotropic behaviour within the temperature range measured here.     

Phase diagrams of binary systems containing n-alkanes,or cyclohexane,or 1-alkanols and 2,3-pentanedione at atmospheric and high pressure

Phase equilibria, for the binary systems {n-alkanes (tridecane, octadecane, or eicosane), or cyclohexane, or 1-alkanol (1-hexadecanol, or 1-octadecanol, or 1-eicosanol) + 2,3-pentanedione} have been determined using a cryometric dynamic method at atmospheric pressure. The influence of pressure on liquidus curve up to 800 MPa was determined for (tridecane, or cyclohexane + 2,3-pentanedione) systems. A thermostated apparatus for the measurements of transition pressures from the liquid to the solid state in two component isothermal solutions (pressometry) was used. The freezing and melting temperatures at a constant composition increase monotonously with pressure. The high-pressure experimental results obtained at isothermal conditions (p–x) were interpolated to well known T–x diagrams.Immiscibility in the liquid phase was observed only for the n-alkanes mixtures. The solubility decreases with an increase of the number of carbon atoms in the n-alkane, or 1-alkanol chain. The higher intermolecular solute–solvent interaction was observed for the 1-alkanols.Experimental solubility results are compared with values calculated by means of the NRTL equation (n-alkanes) and the NRTL and UNIQUAC ASM equations utilizing parameters derived from SLE and LLE results. The existence of a solid–solid first-order phase transition in tridecane, eicosane and 1-alkanols has been taken into consideration in the calculations. The correlation of the solubility data has been obtained with the average root-mean-square deviation of temperature σ < 1.0 K with both equations. The pressure–temperature–composition relation of the high-pressure (solid + liquid) phase equilibria, was satisfactorily presented by the polynomial.     

Densities,refractive indices,and viscosities of N,N-diethylethanol ammonium chloride–glycerol or –ethylene glycol deep eutectic solvents and their aqueous solutions

In this work, we report new experimental data on density, ρ, refractive index, n_D, and viscosity, η, of two deep eutectic solvents, N,N-diethylethanol ammonium chloride–glycerol (DEACG) and N,N-diethylethanol ammonium chloride–ethylene glycol (DEACEG), and their aqueous solutions, over the complete composition range, at temperatures from (298.15 to 343.15) K. Densities and viscosities were measured using the vibrating tube and the falling ball techniques, respectively, while the refractive index at the sodium D line was measured using an automatic refractometer. We aimed to represent the measured properties as a function of temperature and composition, and correlated them using the Redlich–Kister-type equation, for density, a polynomial function, for refractive index, and the Vogel–Fulcher–Tammann (VFT) equation, for viscosity.