Density,relative permittivity,viscosity and speed of sound for 2-methoxyethanol + isobutylamine mixtures

Densities (ρ), relative permittivities (ε), viscosities (η), and speeds of sound (u) at 298.15?K of binary mixtures of 2-methoxyethanol (1)?+?isobutylamine (2), are reported. From all those data, the excess molar volumes, and deviations from mole fraction additivity of the relative permittivity (Δε), viscosity (Δη), speed of sound (Δu), and isentropic compressibility (Δκ) have been calculated. The results for V ^E, Δε, Δln?η, Δu, and Δκ are discussed on the basis of intermolecular interactions between the components of the analysed mixtures.     

Determination of the conditional dimerization constants from the sound velocity data in binary liquid mixtures containing an associating solute and a nonassociating solvent

A new model of calculating the self-association constants in mixtures of two liquids, an associating solute and a nonassociating solvent, is proposed and analyzed. The model assumes additivity of the time of transmission of the acoustic signal with the volume fractions of the components of the mixture. The model was tested for different systems, showing that the results are reliable and close to expectations. The presented attempt seems to be an interesting alternative in interpreting the experimental results of sound velocity measurements in liquid mixtures.     

Thermodynamics of mixtures containing alkoxyethanols. Part xxiii. Speed of sound predictions and ultrasonic studies of hydroxyether + organic solvent mixtures

The ability of different models to predict speeds of sound, u, of binary mixtures formed by alkoxyethanol and octane, oxaalkane or propylamine has been examined. The models applied are: the free length theory (LFT), the collision factor theory (CFT), and equations such as those proposed by Nomoto, Junjie or Van Dael. Collision factor theory, Nomoto's and Junjie's equations provide similar deviations between experimental and calculated u, which is represented quite accurately by these three models. Poorer predictions are obtained when applying the Junjie's equation to propylamine systems, probably due to the existence of strong interactions between unlike molecules in such mixtures. In contrast, slightly better u predictions from CFT are obtained for the systems 2-methoxyethanol + polyether, or hydroxyether + propylamine. The good u predictions obtained using Nomoto's equation remark the validity of Rao's assumption on additivity of molar sound velocity contributions from atoms, atom groups and chemical bonds of the constituent molecules. Discrepancies between experimental and calculated u are larger when using FLT than those obtained from CFT, Nomoto's or Junjie's equations. This has been ascribed to association and size or shape effects. The linear dependence on the molar fractions of the component liquids of the Rao's and Wada's constants suggests that there is no complex formation in the investigated mixtures, and that the interactions present in such systems are of dipolar type.     

Volumetric,viscometric and acoustic properties of binary mixtures of 2-propanol with n -alkanes (C6, C8, C10) at 298.15 and 308.15 K

Densities (ρ), viscosities (η), and speeds of sound, (u) of the binary mixtures of 2-propanol with n-alkanes (n-hexane, n-octane, and n-decane) were measured over the entire composition range at 298.15 and 308.15 K and at atmospheric pressure. Using the experimental values of density, viscosity and speed of sound, the excess molar volumes (V ^E), viscosity deviations (Δη), deviations in speed of sound (Δu), isentropic compressibility (κ _s), deviations in isentropic compressibility (Δκ _s), and excess Gibbs energies of activation of viscous flow (ΔG* ^E) were calculated. These results were fitted to the Redlich–Kister type polynomial equation. The variations of these excess parameters with composition were discussed from the viewpoint of intermolecular interactions in these mixtures. The excess properties are found to be either positive or negative depending on the molecular interactions and the nature of liquid mixtures.     

Binary mixtures containing OMIM PF6: density,speed of sound,refractive index and LLE with hexane,heptane and 2-propanol at several temperatures

Experimental densities, speeds of sound and refractive indices of the binary mixtures OMIM PF₆ (1-methyl-3-octylimidazolium hexafluorophosphate) with hexane, heptane, and 2-propanol were determined at T = 293.15, 298.15, and 303.15 K. Excess molar volumes, changes of refractive index on mixing and deviations in isentropic compressibility for the above systems were performed. The liquid–liquid equilibrium data of these binary mixtures were carried out experimentally and the NRTL and UNIQUAC correlative equations were applied.     

Densities,speeds of sound and refractive indices for binary and ternary mixtures of {diethylcarbonate (1) + p-chloroacetophenone (2) + 1-hexanol (3)} at 303.15 K for the liquid region and at ambient pressure

Densities (ρ), speeds of sound (u) and refractive indices (n_D ), of the ternary mixture (diethylcarbonate + p-chloroacetophenone + 1-hexanol) and the involved binary mixtures (diethylcarbonate + p-chloroacetophenone, diethylcarbonate + 1-hexanol, and p-chloroacetophenone + 1-hexanol) have been measured over the whole composition range at 303.15 K for the liquid region and at ambient pressure. The data obtained are used to calculate isentropic compressibilities k_s , isentropic compressibility deviations Δk_s and refractive index deviations Δn_D , of the binary and ternary mixtures. The data of isentropic compressibility deviations and refractive index deviations of the binary systems were fitted to the Redlich–Kister equation while the best correlation method for the ternary system was found using the Cibulka equation. The experimental data of the constitute binaries and ternaries are analysed to discuss the nature and strength of intermolecular interactions in these mixtures.     

Ultrasonic velocities and isentropic compressibilities of N-methyl-2-pyrrolidone with ketones and branched alcohols at 303.15 K

The ultrasonic sound velocities and densities are measured for the binary mixtures of N-methyl-2-pyrrolidone (NMP) with ketones and branched alcohols at 303.15?K. The ketones include methyl ethyl ketone, methyl propyl ketone, diethyl ketone, methyl isobutyl ketone and cyclohexanone. The branched alcohols include 2-propanol, 2-methyl-1-propanol, 3-methyl-1-butanol, 2-butanol and 2-methyl-2-propanol. The ultrasonic sound velocity data were used to compute isentropic compressibilities (k _s). The deviations in the value of k _s from ideal value were computed. Except cyclohexanone all the binary mixtures formed by NMP with ketones at 303.15?K exhibit negative deviation from ideal behaviour over the entire range of composition. Cyclohexanone with NMP exhibit positive deviation over the entire range of composition. An inversion in the sign of Δk _s from positive to negative was observed for 2-propanol system and negative deviation was observed in four binary mixtures formed by NMP with other branched alcohols at 303.15?K. The ultrasonic sound velocities of these mixtures have been analysed is terms of Free Length Theory (FLT), Collision Factor Theory (CFT) and Nomoto's relation.     

Ultrasonic investigation of effective Debye temperature in multi-component liquid systems at 298.15 K

Assuming the quasi-crystalline model for the multi-component liquid systems, the effective Debye temperature has been investigated from the density and sound velocity measurements of three ternary and three quaternary liquid systems containing n-alkanes over the entire range of mole fractions at 298.15?K. The results obtained have been interpreted in terms of intermolecular interactions and modifications of the internal structure of the mixtures.     

Some Features of the Energetics of Structure Formation in Mixtures of Solvents Differing in Nature and Polarity

Some regularities of the energetics of structure formation in mixtures of polar organic solvents not forming layered structures with liquid hydrocarbons and in mixtures of inert and low-polar diluents at 20 were established. In most cases, the deviation of the methylene group increments from additivity, defining the energy stability of a liquid structure, was distinctly negative. In particular, the increment decreases dramatically from individual higher alcohols to mixtures of propanol and n-octane which model the former in the concentration of functional groups per unit volume, and the structure of mixture is weakened. Solvents of close polarity, in turn, form mixtures whose methylene group increments are well approximated by the additivity law.     

Maximum acceptable deviations from additivity in the photometric analysis of two-component mixtures by Firordt’s method

Photometric analysis of mixtures by Firordt’s method yields relative errors that do not exceed the specified limits only if the deviations from additivity at the analytical wavelengths do not exceed (in their numerical value) their own critical values (δA _crit). These deviations depend on the ratio of component concentrations. By virtue of the analytical geometry technique, we derived equations for the evaluation of δA _crit. These equations allow one to predict the possibility of the precise determination of two components in a mixture under investigation at one and the same set of wavelengths. The developed algorithm was verified on 40 model mixtures of organic compounds.     

A new cubic equation of state for simple fluids: pure and mixture

A two-parameter cubic equation of state is developed. Both parameters are taken temperature dependent. Methods are also suggested to calculate the attraction parameter and the co-volume parameter of this new equation of state. For calculating the thermodynamic properties of a pure compound, this equation of state requires the critical temperature, the critical pressure and the Pitzer’s acentric factor of the component. Using this equation of state, the vapor pressure of pure compounds, especially near the critical point, and the bubble point pressure of binary mixtures are calculated accurately. The saturated liquid density of pure compounds and binary mixtures are also calculated quite accurately. The average of absolute deviations of the predicted vapor pressure, vapor volume and saturated liquid density of pure compounds are 1.18, 1.77 and 2.42%, respectively. Comparisons with other cubic equations of state for predicting some thermodynamic properties including second virial coefficients and thermal properties are given. Moreover, the capability of this equation of state for predicting the molar heat capacity of gases at constant pressure and the sound velocity in gases are also illustrated.     

Studies on solution properties of ternary mixture of acetophenone + n-amyl alcohol + dichloromethane and its corresponding binaries at 298.15 K

The excess values of molar volume (V ^E), viscosity deviation (Δη), deviation in isentropic compressibility (ΔK_S ), excess molar refraction (ΔR) and excess Gibbs energy of activation (ΔG^*E ) of viscous flow have been investigated from the experimentally measured densities, viscosities, sound speeds and refractive indices for three binary mixtures of acetophenone?+?n-amyl alcohol, acetophenone?+?dichloromethane and n-amyl alcohol?+?dichloromethane and their corresponding ternary mixtures at 298.15?K over the entire composition range. The calculated quantities are further fitted to the Redlich–Kister equation to estimate the binary fitting parameters and standard deviations from the regression lines. The excess or deviation properties were found to be either negative or positive depending on the molecular interactions and the nature of liquid mixtures and have been discussed in terms of molecular interactions and structural changes.     

Methodology of the spectrophotometric analysis of organic mixtures: Application of statistical models

Deviations of the absorbance of mixtures from additivity can be detected and predicted using statistical models obtained in the complete factorial experiment. The models correlate the deviations with the composition of a mixture; this allows the optimization of the procedures of spectrophotometric analysis. The advantages and limitations of this approach are demonstrated on an example of the analysis of pharmaceutical preparations and antioxidant mixtures.     

The sound velocity in ideal liquid mixtures from thermal volume fluctuations.

The selection of the correct mixing rule for sound velocity in ideal liquid mixtures determines the interpretation of the sound velocity in real mixtures. This is especially important for the determination of apparent properties of solutes, such as their apparent compressibility. There are different approaches reported in the literature, and this article presents a new derivation of the mixing rule based on statistical mechanics. It is shown that the correlation of volume fluctuations between adjacent components has a crucial influence on the ideal mixing rule.     

The speed of sound in mixtures of the major sea salts. A test of Young's rule for adiabatic PVT properties

The relative sound speed of mixtures of aqueous solutions of NaCl–MgSO₄ and MgCl₂–Na₂SO₄ at I=0.1 and 0.5m have been determined at 5, 15, and 25°C and pressures to 1000 bars. The resulting sound speeds, adiabatic and apparent molal compressibilities have been compared to results estimated from binary solutions using an additivity principle — Young's rule. The estimated sound speeds agree with the measured values for the NaCl–MgSO₄ system to ±0.15 m-sec^–1 and for the Na₂SO₄–MgCL₂ system to ±0.20 m-sec^–1. The deviations increase with increasing ionic strength (±0.08 m-sec^–1 at I=0.1 and ±0.25 m-sec^–1 at I=0.5 m).The sound speed of seawater have also been estimated from 0 to 40°C, 0.1 to 0.7 ionic strength and 0 to 1000 bars. The estimates were found to be in good agreement (±0.4 m-sec^–1) with the measured values.These results indicate that reasonable estimates of the adiabatic PVT properties of dilute mixtures of electrolyte solutions can be made using the additivity principle, without excess mixing terms.     

Physico-chemical properties of binary mixtures of 1-butanol with chloroethanes or chloroethenes at 298.15 K

The densities ρ, speeds of sound u, and viscosities η, of pure 1-butanol, 1,2-dichloroethane, 1,1,1-trichloroethane, 1,1,2,2-tetrachloroethane, trichloroethylene, and tetrachloroethylene and those of their binary mixtures have been measured at 298.15 K and atmospheric pressure over the entire range of compositions. Excess molar volumes V ^E, viscosity deviations Δη, deviation in compressibilities Δκ_s and excess Gibbs energy of activation G*^E, were obtained from the experimental results and those were fitted to Redlich–Kister's type function in terms of mole fractions. Viscosities, speeds of sound and isentropic compressibilities of the binary mixtures have been correlated by means of several empirical and semi-empirical equations. The experimental data are analysed to discuss the nature and strength of intermolecular interactions in these mixtures.     

Thermodynamic study of binary mixtures containing 1-butylpyridinium tetrafluoroborate and methanol, or ethanol

Densities and speeds of sound have been determined for the binary mixture (1-butylpyridinium tetrafluoroborate + methanol, or ethanol) over the temperature range 293.15 K to 323.15 K. From experimental values, excess volume and excess isentropic compressibility have been calculated. The mixtures give negative values for the excess properties. Besides, (vapour + liquid) equilibrium in isothermal conditions has been obtained for these systems at T = 303.15 K and T = 323.15 K, which has allowed us to derive activity coefficients and excess Gibbs functions. Positive deviations from Raoult’s law have been found. A detailed analysis and interpretation of results have been carried out in structural and energetic terms using thermodynamic information of the pure compounds.     

Thermodynamic Investigation of Dimethyl Sulfoxide Binary Mixtures at 293.15 and 313.15 K

Densities (ρ), speeds of sound (u), and isentropic compressibilities (k _S) of binary mixtures of dimethyl sulfoxide (DMSO) with water, methanol, ethanol, 1-propanol, 2-propanol, acetone and cyclohexanone have been measured over the entire composition range at 293.15 and 313.15 K. The excess molar volumes (V ^E), the deviations in speed of sound (u ^E) and the deviations in isentropic compressibility (k _S ^E) have been determined. The V ^E, u ^E and k _S ^E values were fitted by the Redlich-Kister polynomial equation and the A _k coefficients as well as the standard deviations (d) between the calculated and experimental values have been derived. The results obtained are discussed from the viewpoint of the existence of interactions between the components of the binary mixtures.     

Excess molar volumes and ultrasonic studies of dimethylsulphoxide with ketones at T = 303.15 K

Excess molar volumes (V^E) and ultrasonic sound velocities at T = 303.15 K and ambient pressure have been measured as a function of composition for the binary liquid mixtures of dimethylsulphoxide (DMSO) with ketones. The ketones studied in the present investigation include ethyl methyl ketone (EMK), diethylketone (DEK), methyl propyl ketone (MPK), methyl isobutyl ketone (MIBK), and cyclohexanone (CH). The V^E values were measured using a dilatometer and were positive over the entire mole fraction range for all systems except in the binary system DMSO with EMK where the V^E exhibits an inversion in sign. The experimental V^E values have been correlated using Redlich–Kister and Hwang et al. equations. The ultrasonic sound velocities for the above systems have been measured with a single crystal interferometer at a frequency of 3 MHz. The sound velocity (u) data have been used to calculate isentropic compressibility (K_s) and deviation in isentropic compressibility (ΔK_s) over the entire range of volume fraction. The sound velocity data have been predicted in terms of free length theory (FLT), collision factor theory (CFT), and Nomoto relation. The results reveal that all the theories gave a satisfactory estimate of the sound velocity. The deviations in values of isentropic compressibility (ΔK_s) were negative over the entire range of volume fraction in all the binary liquid mixtures. The results are interpreted with respect to possible molecular interactions between components.