Analysis of volumes of mixing for propyl and butyl formate withn-alkanes in terms of the Nitta model

The excess molar volumes of eight binary systems formed of propyl or butyl formate with four n-alkanes (from C₆ to C₉) have been determined at 25°C and atmospheric pressure. The data were obtained indirectly from densities measured experimentally with a vibrating-tube densimeter and then compared with those estimated using the Nitta model. This method yields good predictions of the symmetry of the v ^E curves given an average overall error for all the systems analyzed here smaller than 6 percent.     

Excess molar volumes of diethyl carbonate with hydrocarbons or tetrachloromethane at 25°C

The excess molar volumes V _m ^E at atmospheric pressure and at 25°C for binary mixtures of diethyl carbonate with n-heptane, n-decane, n-tetradecane, 2,2,4-trimethylpentane, cyclohexane, benzene, toluene, or tetrachloromethane have been obtained over the whole mole-fraction range from densities measured with a vibrating-tube densimeter. The V _m ^E are positive for all the systems investigated, except for the mixture with toluene which is negative. The results for V _m ^E together with data previously published on excess molar enthalpies H _m ^E and excess molar Gibbs energies G _m ^E , suggest interactions between carbonate and hydrocarbons which are stronger with aromatic than with aliphatic hydrocarbons.Thermodynamics of binary mixtures containing organic carbonates, Part 10.     

Excess Molar Volumes and Excess Partial Molar Volumes of Triethylene Glycol Monoethyl Ether–n-Alcohol Mixtures at 25°C

We have measured excess molar volumes V^E _m of binary mixtures of triethylene glycol monoethyl ether with methanol, ethanol, 1-propanol, 1-pentanol, and 1-hexanol over the full range of compositions at 25°C. The measurements were carried out with a continuous-dilution dilatometer. The excess molar volumes V^E _m are negative over the entire range of composition for the systems triethylene glycol monoethyl ether + methanol, + ethanol, and + 1-propanol and positive for the remaining systems, triethylene glycol monoethyl ether + 1-pentanol, and + 1-hexanol. The excess V^E _m increases in the positive direction with increasing chain length of the n-alcohol. The measured excess volumes have been compared to our previous published data with an effort to assess the effects of replacing methyl by ethyl groups and of inserting oxyethylene groups. The results have been used to estimate the excess partial molar volumes V^E _m,i of the components. The behavior of V^E _m and V^E _m,i with composition and the number of carbon atoms in the alcohol molecule is discussed.     

Thermodynamic Properties of Binary Mixtures of Cyclohexanone with n-Alkanols (C1–C5) at 293.15 K

The excess molar volumes (V^E), excess surface tensions (σ^E), and deviations in molar refraction (R^E) and isentropic compressibility (k_s^E) of binary mixtures of cyclohexanone with methanol, ethanol, 1-propanol, 1-butanol, and 1-pentanol have been determined over the entire composition range at 293.15 K. The results were fitted by the Redlich–Kister polynomial equation and the corresponding binary coefficients A_k have been derived. The standard deviations between the calculated and the experimental excess properties have been determined. The results provide information on the interactions of the molecules in the pure liquids as well as in the binary mixtures.     

Isothermal vapor–liquid equilibrium at 333.15 K and excess molar volumes at 298.15 K for the ternary system di-isopropyl ether + n-propyl alcohol + toluene and its binary subsystems

Isothermal vapor–liquid equilibrium data at 333.15 K are reported for the ternary system di-isopropyl ether (DIPE) + n-propyl alcohol + toluene and the binary subsystems DIPE + n-propyl alcohol, DIPE + toluene and n-propyl alcohol + toluene by using headspace gas chromatography. The excess molar volumes at 298.15 K for the same binary and ternary systems were also determined by directly measured densities. The experimental binary and ternary vapor–liquid equilibrium data were correlated with different G^E models and the excess molar volumes were correlated with the Redlich–Kister equation for the binary systems and the Cibulka equation for the ternary system, respectively.     

Thermodynamische Untersuchungen ann-Alkan/n-Alkin-Systemen

The vapour-liquid equilibrium data obtained from isobarict-x-measurements have been used for calculation of the group UNIFAC parameters and excess free enthalpyG ^E of binary mixturesn-alkanes with isomericn-alkynes. The UNIFAC model gives satisfactory predictions for the systems studied. The temperature dependence ofG ^E was estimated on the basis of the heats of mixing measured earlier. The influence of the position of triple bond in the molecules ofn-alkynes on the excess thermodynamic functions is considered.

     

Thermodynamics of liquid mixtures containing a very strongly polar compound: Part 6. DISQUAC characterization of N,N-dialkylamides

Systems of N,N di(n-alkylamides) (hereafter, N,N-dialkylamides) with alkane, benzene, toluene, 1-alkanol or 1-alkyne have been investigated in the framework of the DISQUAC model. The corresponding interaction parameters are reported. They change regularly with the molecular structure of the mixture components. This variation is similar to those encountered when treating other systems in terms of DISQUAC. The model describes consistently a whole set of thermodynamic properties: liquid–liquid equilibria (LLE), vapor–liquid equilibria (VLE), solid–liquid equilibria (SLE), molar excess Gibbs energies (G^E), molar excess enthalpies (H^E), molar excess heat capacities at constant pressure (C_P^E), partial molar excess properties at infinite dilution, enthalpies and heat capacities. The model also provides good results for the Kirkwood–Buff integrals and for the linear coefficients of preferential solvation. For ternary systems, DISQUAC predictions on VLE and H^E, obtained using binary parameters only, are in good agreement with the experimental data. A short comparison between DISQUAC and Dortmund UNIFAC results is shown. DISQUAC improves UNIFAC results on H^E and C_P^E, magnitudes which strongly depend on the molecular structure. The investigated mixtures behave similarly to those characterized by thermodynamic properties which arise from dipolar interactions. Association/solvation effects do not play, as a whole, an important role in the studied systems. This may explain that the ERAS model fails when representing the thermodynamic properties of dimethylformamide + 1-alkanol mixtures.     

Volumetric properties of ternary (IL + 2-propanol or 1-butanol or 2-butanol + ethyl acetate) systems and binary (IL + 2-propanol or 1-butanol or 2-butanol) and (1-butanol or 2-butanol + ethyl acetate) systems

The experimental densities for the binary or ternary systems were determined at T = (298.15, 303.15, and 313.15) K. The ionic liquid methyl trioctylammonium bis(trifluoromethylsulfonyl)imide ([MOA]⁺[Tf₂N]⁻) was used for three of the five binary systems studied. The binary systems were ([MOA]⁺[Tf₂N]⁻ + 2-propanol or 1-butanol or 2-butanol) and (1-butanol or 2-butanol + ethyl acetate). The ternary systems were {methyl trioctylammonium bis(trifluoromethylsulfonyl)imide + 2-propanol or 1-butanol or 2-butanol + ethyl acetate}. The binary and ternary excess molar volumes for the above systems were calculated from the experimental density values for each temperature. The Redlich–Kister smoothing polynomial was fitted to the binary excess molar volume data. Virial-Based Mixing Rules were used to correlate the binary excess molar volume data. The binary excess molar volume results showed both negative and positive values over the entire composition range for all the temperatures.The ternary excess molar volume data were successfully correlated with the Cibulka equation using the Redlich–Kister binary parameters.     

Ionic interactions in solution: VI. The activity expansion and the association concept

The activity expansion equation which expresses the solute concentration as a series expansion of the activities of the solute species is used to reach a reformulation of the mean activity coefficient of a binary symmetrical electrolyte in solution. The result is displayed as the product of a shortrange term and a long-range term f_±=f _± ^S ·f^L _±, from which a straightforward derivation of the Bjerrum treatment is obtained. The analogy with an equivalent formulation for the molar conductance coefficient which results from the application of the echo-effect is emphasized. A simple formulation of the ion pair distribution function is proposed which is particularly powerful for ionic systems involving strong interactions. It is shown that the variable which controls the excess transport and thermodynamic quantities is not so much the stoichiometric concentration but rather the product of the concentration with the short-range factor f _± ^S of the activity coefficient product derived in the present work. In dilute solutions this factor becomes the so-called fraction of free ions originally introduced somewhat empirically by Bjerrum by means of a chemical model.Dedicated to Johannes Coetzee on the occasion of his 65th Birthday.     

Excess Molar Volumes and Excess Partial Molar Volumes of Triethylene Glycol Monomethyl Ether–n-Alcohol Mixtures at 25°C

The excess molar volumes V ^E have been measured for binary mixtures of triethylene glycol monomethyl ether with methanol, ethanol, 1-propanol, 1-pentanol, and 1-hexanol as a function of composition using a continuous–dilution dilatometer at 25°C at atmosphere pressure. V ^E are negative over the entire range of composition for the systems triethylene glycol monomethyl ether + methanol, + ethanol, and + 1-propanol, and positive for the remaining systems, containing 1-pentanol and + 1-hexanol. V ^E increases in a positive direction with increasing carbon chain length of the n-alcohol. The excess partial molar volumes V _i ^E of the components were evaluated from the V ^E results. The behavior of V ^E and V _i ^E with composition and the number of carbon atoms in the alcohol molecule is discussed.     

Effect of Temperature on the Volumetric Properties of [Difurylmethane+(C<Subscript>2</Subscript>–C<Subscript>6</Subscript>) Alkan-1-ol] Binary Systems: Analyses of New and Literature Density Data in the Temperature Range 288.15–308.15 K

Densities, ρ, of the binary systems {difurylmethane + (ethanol or propan-1-ol or butan-1-ol or pentan-1-ol or hexan-1-ol)} have been measured with an Anton Paar DMA 4500 vibrating-tube densimeter over the entire composition range at 288.15 and 308.15 K and atmospheric pressure. The measured and literature densities of [difurylmethane + n-alkanol] binary systems have been used to check the validity of the relationship describing the dependence of density on composition. This relation is useful for obtaining interpolated ρ values corresponding to the experimental data. Excess molar volumes (V _m^E) of each mixture, limiting (V _m,i ^E,∞) and excess partial (V _m,i ^E) molar volumes and the limiting partial molar expansion (E _p,i ^∞) of both components of each binary system have been examined to provide insight into the temperature variations of the intermolecular interactions and molecular packing efficiencies. The results have been discussed in terms of specific intermolecular interactions and structural effects.     

Physical Properties of Binary Liquid Systems: Ethanoic Acid/Propanoic Acid/Butanoic Acid with Cresols

Density, viscosity and surface tension of nine binary liquid systems: ethanoic acid, propanoic acid and butanoic acid with o-cresol, m-cresol and p-cresol have been determined at 298.15, 308.15 and 318.15 K over the complete compositional range. From the experimental results the excess values of molar volume (V ^E), viscosity (η ^E), Gibbs free energy for the activation of flow (ΔG ^E) and surface tension (σ ^E) were evaluated. The excess values were fitted to the Redlich–Kister type equation using a nonlinear regression technique. The Grunberg–Nissan parameter, d, was also calculated. From the sign and magnitude of the V ^E, η ^E, ΔG ^E, σ ^E, and d values, it is concluded that specific interactions are present in all of the nine binary mixtures under study. V ^E is negative for carboxylic acid–cresol mixtures at all temperatures and over the entire composition range. The values of η ^E, ΔG ^E and σ ^E are positive over the whole range of composition and increase with increasing temperature at a constant mole fraction of the carboxylic acid, confirming the existence of specific interactions in these binary mixtures. Further, the viscosity data of the binary systems were fitted to various theoretical/empirical models. The binary viscosity data is well represented by the Auslander model. Surface tension data were fitted to various theoretical/empirical models. The binary mixture surface tension data are well represented by the model given by Zihao and Jufu.     

Thermodynamics of Mixtures with Strongly Negative Deviations from Raoult's Law. VII. Excess Molar Volumes at 25°C for 1-Alkanol + N-Methylbutylamine Systems—Characterization in Terms of the ERAS Model

Excess molar volumes, V ^E _m, at 25^°C and atmospheric pressure, over the entire composition range for binary mixtures of methanol, ethanol, 1-propanol, 1-butanol, 1-pentanol, 1-hexanol, 1-heptanol, and 1-octanol with-methylbutylamine are reported. They are calculated from densities measured with a vibrating-tube densimeter. All the excess volumes are large and negative over the entire composition range. This indicates strong interactions between unlike molecules, which are greatest for the system involving methanol, characterized by the most negative V ^E _m. For the other solutions, V ^E _m at equimolar composition, is approximately the same. The V ^E _m curves vs. mole fraction are nearly symmetrical. The ERAS model is applied to 1-alkanol + N-methylbutylamine, and 1-alkanol + diethylamine systems. The ERAS parameters confirm that the strongest interactions between unlike molecules are encountered in solutions with methanol. The model consistently describes V ^E _m and excess molar enthalpies H ^E _m of the mixtures studied.     

Ternary excess molar enthalpies for the mixtures of methanol and ethanol with tetrahydropyran or 1,4-dioxane at 298.15 K

Ternary excess molar enthalpies, H_m^E, at 298.15 K and atmospheric pressure measured by using a flow microcalorimeter are reported for the (methanol+ethanol+tetrahydropyran) and (methanol+ethanol+1,4-dioxane) mixtures. The pseudobinary excess molar enthalpies for all the systems are found to be positive over the entire range of compositions. The experimental results are correlated with a polynomial equation to estimate the coefficients and standard errors. The results have been compared with those calculated from a UNIQUAC associated solution model in terms of the self-association of alcohols as well as solvation between unlike alcohols and alcohols with tetrahydropyran or 1,4-dioxane. The association constants, solvation constants and optimally fitted binary parameters obtained solely from the pertinent binary correlation predict the ternary excess molar enthalpies with an excellent accuracy.     

Investigation of ultrasonic speeds of sound and excess parameters in binary liquid mixtures of N-alkanes with octan-2-ol using different empirical theories at 298.15 K

Ultrasonic velocity, density and percentage deviation in velocity were measured for mixtures of n-alkanes, namely, n-octane, n-decane, n-dodecane and n-tetradecane with octan-2-ol at 298 K. The experimental sound velocity data were compared by using three theoretical relations, namely, Nomoto relation, Vandael ideal mixing relation and Schaaffs collision factor theory to predict which one of them agrees the experimental data. It was observed that Nomoto relation was the best suited method in all the four binary systems. Hence, in the real time applications which are using the above said components can be handled without experimental expenses. The experimental data were used to calculate the interaction parameter (α), adiabatic compressibility (β), intermolecular free length (L_f), excess velocity (U^E), excess impedance (Z^E) and excess volume (V^E) which were discussed to identify the molecular interactions in terms of non-ideality in the binary liquid mixtures. It was observed that the increase of mole fraction of octan-2-ol with different n-alkanes dipole–induced dipole interactions were supported.     

Dielectric Relaxation Studies of Binary Mixture of α‐Picoline and Methanol Using Time Domain Reflectometry at Different Temperatures

Complex permittivity spectra of binary mixtures of varying concentrations of α‐picoline and methanol (MeOH) were obtained using time domain reflectometry (TDR) technique over frequency range 10 MHz to 25 GHz at 283.15 K, 288.15 K, 293.15 K and 298.15 K temperatures. The dielectric relaxation parame‐ ters namely static permittivity (σ₀), high frequency limit permittivity (σ_oo1) and the relaxation time (ρ) were determined by fitting complex permittivity data to the single Debye/Cole‐Davidson model. Complex non linear least square (CNLS) fitting procedure was carried out using LEVMW software. The excess static permittivity (σ₀^E) and the excess inverse relaxation time (1/ρ)^E which contains information regarding mo‐ lecular structure and interaction between polar — polar liquids, were also determined. From the experimental data, effective Kirkwood correlation factor (g^eff) and Bruggeman factor (f_B) were calculated. Excess parameters were fitted to the Redlich‐Kister polynomial equation. The values of static permittivity and relaxation time increase non‐linearly with increase in the mol fraction of MeOH at all temperatures. The values of excess static permittivity (σ₀^E) and the excess inverse relaxation time (1/ρ)^E are negative for the studied α‐picoline — MeOH system at all temperatures.     

Isothermal vapor–liquid equilibria and excess molar volumes for the ternary mixtures containing 2-methyl pyrazine

Isothermal vapor–liquid equilibrium (VLE) data at 353.15 K and excess molar volumes (V^E) at 298.15 K are reported for the binary systems of ethyl acetate (EA)+cyclohexane and EA+n-hexane and also for the ternary systems of EA+cyclohexane+2-methyl pyrazine (2MP) and EA+n-hexane+2MP. The experimental binary VLE data were correlated with common g^E model equations. The correlated Wilson parameters of the constituent binary systems were used to calculate the phase behavior of the ternary mixtures. The calculated ternary VLE data using Wilson parameters were compared with experimental ternary data. The experimental excess molar volumes were correlated with the Redlich–Kister equation for the binary mixtures, and Cibulka’s equation for the ternary mixtures.     

Vapor–liquid equilibria of 2-butanol + aromatic hydrocarbons at 308.15 k

Vapor–liquid equilibria (VLE) data of 2-butanol?+?benzene or toluene or o- or m- or p-xylene measured by static method at 308.15?±?0.01?K over the entire composition range are reported. The excess molar Gibbs free energies of mixing (G ^E) for these binary systems have been calculated from total vapor pressure data using Barker's method. The G ^E for these binary systems are also analyzed in terms of the Mecke–Kempter type of association model with a Flory contribution term using two interaction parameters and it has been found that this model describes well the G ^E values of binary systems benzene or toluene.     

Excess volumes of the binary mixtures 1,2-dichloroethane ? n -alkanols [C2?C6]

Volume changes on mixing of binary systems formed by 1,2-dichloroethane andn-alcohols, namely, ethanol,n-propanol,n-butanol,n-pentanol andn-hexanol were measured as a function of composition at 30, 35, 40 and 45 °C. At all compositions theV ^E values are all positive for all systems. The molar excess volumes of mixing for equimolar mixtures increase as the length of carbon chain increases.V ^E becomes more positive on increasing temperature. The positive value of the excess volume has been attributed to breaking of hydrogen bonds of associated species of alcohol by dilution with 1,2-dichloroethane.     

Densities, Viscosities, Speeds of Sound, FT-IR and 1H-NMR Studies of Binary Mixtures of n-Butyl Acetate with Ethanol, Propan-1-ol, Butan-1-ol and Pentan-1-ol at?298.15, 303.15, 308.15 and 313.15?K

Densities, viscosities and speeds of sound of binary mixtures of ethanol, propan-1-ol, butan-1-ol and pentane-1-ol with n-butyl acetate have been measured over the entire range of composition at temperatures of 298.15, 303.15, 308.15 and 313.15 K and atmospheric pressure. From the experimental densities, viscosities and speeds of sound, the excess molar volumes V ^E, deviations in viscosity ????, and deviations in isentropic compressibility ???? _S have been calculated. The excess molar volumes and deviations in isentropic compressibility are positive for all the binary systems studied over the whole composition, while deviations in viscosities are negative for all of the binary mixtures. The excess molar volumes, deviations in viscosity, and deviations in isentropic compressibility have been fitted to a Redlich?CKister type polynomial equation. FTIR and ¹H-NMR studies of these mixtures are also reported.