Thermophysical properties of dimethyl sulfoxide + cyclic and linear ethers at 308.15 K: Application of an extended cell model

Excess molar enthalpies and heat capacities of dimethyl sulfoxide + 1,4-dioxane, dimethyl sulfoxide + 1,3-dioxolane, dimethyl sulfoxide + tetrahydropyran, dimethyl sulfoxide + tetrahydrofuran, dimethyl sulfoxide + 1,2-dimethoxyethane, and dimethyl sulfoxide + 1,2-diethoxyethane have been measured at 308.15 K and at atmospheric pressure using an LKB micro-calorimeter and a Perkin-Elmer differential scanning calorimeter. Heat capacities of pure components were determined in the range (293.15 < T/K < 423.15). The results of excess molar enthalpies were fitted to the Redlich-Kister polynomial equation to derive the adjustable parameters and standard deviations, and were used to study the nature of the molecular interactions in the mixtures. Results of excess molar enthalpy were interpreted by an extended modified cell model.     

Molar heat capacities for (1-butanol + 1,4-butanediol, 2,3-butanediol, 1,2-butanediol, and 2-methyl-2,4-pentanediol) as function of temperature

The isobaric molar heat capacities for the binary mixtures (1-butanol + 1,4-butanediol) were determined in the temperature range from (293 to 353) K from measurements of isobaric specific heat capacity in a differential scanning calorimeter. The composition dependencies of the excess molar isobaric heat capacities obtained from the experimental results were fitted by the Redlich-Kister polynomials. Above T = 303.15 K, the excess isobaric molar heat capacities are negative over the whole composition range and absolute values increase with temperature. For temperatures (293.15 and 298.15) K, the excess values show S-shaped character. These excesses are however in general very small; at the temperature 298.15 K smaller than 0.1 J · K⁻¹ · mol⁻¹.Additionally, the isobaric molar heat capacities of 2,3-butanediol, 1,2-butanediol, and 2-methyl-2,4-pentanediol were determined over a similar temperature range. The experimental data for all diols are compared with available literature data and values estimated from group additivity.     

Thermodynamic study of heptane + secondary, tertiary and cyclic amines mixtures. Part IV. Excess and solvation enthalpies at 298.15 K

Partial molar enthalpies and excess enthalpies H^E of binary mixtures of heptane + secondary and tertiary n-alkyl, primary cycloalkyl, and secondary (hetero)cyclic amines have been determined at 298.15 K by isothermal titration calorimetry in the whole composition range. All mixtures showed positive H^E values which decrease with increasing amine size in each category, and decrease in the order cyclic primary > cyclic secondary > linear primary [1] > secondary > tertiary when comparing amines of similar size in different categories. From partial molar enthalpies at infinite dilution and known enthalpies of vaporization, the solvation enthalpies have been calculated either for heptane in amines and for amines in heptane. These quantities, together with their cavitational and interactional terms obtained applying the scaled particle theory, are discussed to get insight into the types and relative strength of solute-solvent interactions and into their effects on molecular structure features such as branching and cyclization.     

Molar excess enthalpies of ethyl acetate + alkanols at T = 298.15 K, p = 10.0 MPa

A commercial flow-mixing isothermal calorimeter was tested by measuring heat of mixing curves for exothermic, endothermic, S-shaped and double minimum molar excess enthalpy mixtures at high pressure. The results show this calorimeter is able to produce good quality data. Molar excess enthalpies for ethyl acetate mixed with a series of simple alkanols were measured at T = 298.15 K and p = 10 MPa.     

Experimental and predicted excess molar enthalpies of binary mixtures containing 2,2′-oxybis[propane], benzene,butan-1-ol, 2-methylpropan-1-ol, 2-methyl-2-ene-1-propanol at 303.15 K

Excess molar enthalpies H^E have been measured for liquid binary mixtures of 2,2′-oxybis[propane] (diisopropylether ‘DIPE’), or, benzene + butan-1-ol, +2-methylpropan-1-ol (isobutanol), +2-methyl-2-ene-1-propanol (isobutenol), +n-heptane at 303.15 K and constant pressure using a C80, Setaram calorimeter. A Redlich–Kister type equation was used to correlate experimental results.     

Experimental (solid + liquid) phase equilibria of (alkan-1-ol + benzonitrile), (amine + benzonitrile) binary mixtures,and (decan-1-ol + decylamine + benzonitrile) ternary mixtures

(Solid + liquid) phase diagrams, SLE have been determined for (octan-1-ol, or nonan-1-ol, or decan-1-ol, or undecan-1-ol + benzonitrile) and for (hexylamine, or octylamine, or decylamine, or 1,3-diaminopropane + benzonitrile) using a cryometric dynamic method at atmospheric pressure. Simple eutectic systems with complete immiscibility in the solid phase and complete miscibility on the liquid phase have been observed. The solubility decreases with an increase of the number of carbon atoms in the alkan-1-ol, or amine chain. The temperature of the eutectic points increases and shifts to lower alkan-1-ol, or amine mole fractions as the alkyl chain length of the alkan-1-ol, or amine increases. The higher intermolecular interaction was observed for the (alkan-1-ol + benzonitrile) systems.     

Excess molar enthalpies of methylformate + (1-propanol, 2-propanol, 1-butanol, 2-butanol and 1-pentanol) at T = 298.15 K, p = (5.0, 10.0) MPa, and methylformate + 1-propanol at T = 333.15 K, p = 10.0 MPa

A high pressure flow-mixing isothermal calorimeter is used to determine the excess molar enthalpies of methylformate + (1-propanol, 2-propanol, 1-butanol, 2-butanol and 1-pentanol) at T = 298.15 K and p = (5.0, 10.0) MPa, and methylformate + 1-propanol at T = 333.15 K and p = 10.0 MPa. The Redlich-Kister equation is fit to the experimental results.     

Densities, viscosities, and ultrasonic velocity studies of binary mixtures of trichloromethane with methanol, ethanol, propan-1-ol, and butan-1-ol at T = (298.15 and 308.15) K

Densities, viscosities, and ultrasonic velocities of binary mixtures of trichloromethane with methanol, ethanol, propan-1-ol, and butan-1-ol have been measured over the entire range of composition, at (298.15 and 308.15) K and at atmospheric pressure. From the experimental values of density, viscosity, and ultrasonic velocity, the excess molar volumes (V^E), deviations in viscosity (Δη), and deviations in isentropic compressibility (Δκ_s) have been calculated. The excess molar volumes, deviations in viscosity and deviations in isentropic compressibility have been fitted to the Redlich-Kister polynomial equation. The Jouyban-Acree model is used to correlate the experimental values of density, viscosity, and ultrasonic velocity.     

Thermodynamic interactions in binary mixtures of anisole with ethanol, propan-1-ol, propan-2-ol, butan-1-ol, pentan-1-ol, and 3-methylbutan-1-ol at T = (298.15, 303.15, and 308.15) K

In this paper, excess thermodynamic functions have been computed from the measured values of density, viscosity, and refractive index at T = (298.15, 303.15, and 308.15) K, ultrasonic velocity at T = 298.15 K over the entire mixture composition range of (anisole with ethanol, propan-1-ol, propan-2-ol, butan-1-ol, pentan-1-ol, or 3-methyl butan-1-ol). Excess molar volume, V^E has been calculated from densities, whereas deviations in viscosity, Δη, were computed from the measured viscosities. From ultrasonic velocities, isentropic compressibilities were calculated, from which deviations in isentropic compressibility, Δk_s have been computed. Lorenz-Lorentz mixture rule was used to compute molar refractivity, R from refractivity index data and from these data, deviations in molar refractivity, ΔR have been computed. Computed thermodynamic quantities have been fitted to Redlich and Kister polynomial equation to derive the coefficients and standard errors between experimental and predicted quantities. Intermolecular interactions between anisole and alkanols have been studied based on the computed excess thermodynamic quantities.     

Excess molar enthalpies of the ternary mixtures (1-hexene + tetrahydrofuran or 2-methyltetrahydrofuran + methyl tert-butyl ether) at the temperature 298.15 K

Microcalorimetric measurements of excess enthalpies at the temperature T = 298.15 K are reported for the binary mixture, (x₁C₆H₁₂ + x₂C₄H₈O) and the two ternary mixtures {x₁C₆H₁₂ + x₂(C₄H₈O or C₅H₁₀O) + x₃(C₅H₁₂O)}. Smooth representations of the results are presented and used to construct constant excess molar enthalpy contours on Roozeboom diagrams. It is shown that good estimates of the ternary enthalpies can be obtained from the Liebermann and Fried model, using only the physical properties of the components and their binary mixtures.     

Excess molar volumes of N,N-dimethylformamide + 2-pentanone + alkan-1-ols mixed solvent systems at 303.15 K

Accurate excess molar volumes (V^E), at ambient pressure and 303.15 K, have been determined in the ternary liquid mixtures of N,N-dimethylformamide (DMF) + 2-pentanone (PE) + 1-alkan-1-ols (C₃-C₆) and in the binary mixtures of PE + alkan-1-ols (C₃-C₆) as a function of composition. The alkanols include 1-propanol, 1-butanol, 1-pentanol and 1-hexanol. The intermolecular interactions and structural effects were analyzed on the basis of the measured and derived properties. Excess molar volumes increase in magnitude with increase in chain length of alcohol. Valuable information on the behavior and governing factors of the liquid structure of the strongly associated solvents studied were inferred from the parameters deduced. The V^E results were correlated and fitted by the Redlich-Kister equation for binary mixtures and by the Cibulka equation for ternary mixtures, as a function of mole fraction. Several predictive empirical relations were applied to predict the excess volumes of ternary mixtures from the binary mixing data. An analysis of the data indicates a good agreement between experimental results and predicted values in all ternary systems. A discussion is presented and deviations are interpreted in terms of size, shape, the position of ketone group, the chain length of alkanol and hydrogen bond effects in the liquid mixtures studied to explain chemical and thermophysical behavior.     

Excess molar enthalpies of formamide + some alkan-1-ols (C1-C6) and their correlations at 298.15 K

Excess molar enthalpies, H^E for the binary systems formamide+methanol, + ethanol, + propan-1-ol, + butan-1-ol, + pentan-1-ol, and + hexan-1-ol have been measured at 298.15 K and atmospheric pressure with a Paar 1455 solution calorimeter. All the system present endothermic events and showed maximum positive H^E values around 0.40-0.50 mole fraction of formamide. The H^E values increases in the order: methanol<ethanol<propan-1-ol<butan-1-ol<pentan-1-ol<hexan-1-ol. Experimental showed insolubility of hexan-1-ol in formamide around x≅0.5 mole fraction of formamide. The excess enthalpies of the above mentioned binary systems, were used to discuss interaction between the alkan-1-ols and formamide molecules. The results are interpreted to gain insight into the changes in molecular association equilibria and structural effects in these systems through O···HO hydrogen bonding. The experimental data have been correlated using Redlich-Kister polynomials. In this research work, the thermodynamics models were also tested: NRTL, Wilson models and their parameters were calculated. The correlation of excess enthalpy data in the systems using NRTL model provides good results.     

Excess Gibbs energies and volumes of the ternary system chloroform + tetrahydrofuran + cyclohexane at 298.15 K

Vapour–liquid equilibria and densities for the ternary system chloroform + tetrahydrofuran + cyclohexane and for the binary mixtures containing chloroform have been determined at 298.15 K. Vapour–liquid equilibrium data have been collected by head-space gas-chromatographic analysis of the vapour phase directly withdrawn from an equilibration apparatus. Density measurements have been carried out by means of a vibrating tube densimeter. Molar excess Gibbs energies G^E and volumes V^E, as well as activity coefficients and apparent molar volumes of the components, have been obtained from the measured quantities and discussed. The binary chloroform + tetrahydrofuran displays negative deviations from ideality, while chloroform + cyclohexane positive deviations, for both volume and Gibbs energy. The G^E's and V^E's for the ternary system are positive in the region rich in cyclohexane while negative in the region rich in chloroform + tetrahydrofuran. This indicates that hydrogen bonding between chloroform and tetrahydrofuran molecules produces negative values of G^E and V^E and strongly influences the behaviour of the ternary system.     

Apparent molar volumes and apparent molar heat capacities of aqueous N-acetyl-d-glucosamine at temperatures from 278.15 K to 368.15 K and of aqueous N-methylacetamide at temperatures from 278.15 K to 393.15 K at the pressure 0.35 MPa

We determined apparent molar volumes V_? from densities measured with a vibrating-tube densimeter at 278.15 ? (T/K) ? 368.15 and apparent molar heat capacities C_p,? with a twin fixed-cell, differential, temperature-scanning calorimeter at 278.15 ? (T/K) ? 363.15 for aqueous solutions of N-acetyl-d-glucosamine at m from (0.01 to 1.0) mol · kg⁻¹ and at p = 0.35 MPa. We also determined V_? at 278.15 ? (T/K) ? 368.15 and C_p,? at 278.15 ? (T/K) ? 393.15 for aqueous solutions of N-methylacetamide at m from (0.015 to 1.0) mol · kg⁻¹ and at p = 0.35 MPa. Empirical functions of m and T for each compound were fitted to our results, which are then compared to those for N,N-dimethylacetamide. Estimated values of Δ_rV_m(m, T) and Δ_rC_p,m(m, T) for formation of aqueous N-acetyl-d-glucosamine from aqueous d-glucose and aqueous acetamide are calculated and discussed.     

Physical properties and their corresponding changes of mixing for the ternary mixture acetone + n-hexane + water at 298.15 K

Experimental density and the refractive index of the ternary mixture acetone + n-hexane + water, and their binary systems were experimentally measured and correlated at 298.15 K and atmospheric pressure. A maximum in refractive indices has been observed for the acetone + water system while the excess molar volume and the molar refraction change are all negative. For the mixture acetone + n-hexane, the excess molar volume is always positive and the molar refraction change of mixing showed a S-shaped dependence on acetone composition. The excess molar volumes and molar refraction changes of mixing were correlated using the Redlich-Kister expression and Cibulka equation. The coefficients and standard deviation between the experimental and fitted values were estimated. Good agreement between both results was obtained.     

Vapour pressure and excess Gibbs energy of binary 1,2-dichloroethane + cyclohexanone,chloroform + cyclopentanone and chloroform + cyclohexanone mixtures at temperatures from 298.15 to 318.15 K

The vapour pressures of the binary systems 1,2-dichloroethane + cyclohexanone, chloroform + cyclopentanone and chloroform + cyclohexanone mixtures were measured at temperatures between 298.15 and 318.15 K. The vapour pressures vs. liquid phase composition data for three isotherms have been used to calculate the activity coefficients of the two components and the excess molar Gibbs energies, G^E, for these mixtures, using Barker's method. Redlich–Kister, Wilson, NRTL and UNIQUAC equations, taking into account the vapour phase imperfection in terms of the 2-nd virial coefficient, have represented the G^E values. No significant difference between G^E values obtained with these equations has been observed. Our data on vapour–liquid equilibria (VLE) and excess properties of the studied systems are examined in terms of the DISQUAC and modified UNIFAC (Dortmund) predictive group contributions models.     

Partial molar volumes of (acetonitrile + water) mixtures over the temperature range (273.15 to 318.15) K

Isothermal molar volume data of (acetonitrile + water) mixtures, between T = 273.15 K and T = 318.15 K, extracted from different sources are combined and treated as a single set to even out minor differences between sources and to increase the number of data points for each temperature. Tikhonov regularization is applied to compute the isothermal first and second derivatives of these data with respect to molar composition. For the reference temperature of 298.15 K, this computation is extended to the third derivative. Generalized Cross Validation is used to guide the selection of the regularization parameter that keeps noise amplification under control. The resulting first derivatives are used to construct the partial molar volume curves which are then checked against published results. Properties of the partial molar volumes are analysed by examining their derivatives. Finally the general shape of the second derivative curve of molar volume is explained qualitatively in terms of tripartite segmentation of the molar composition interval but quantitative comparisons are required to confirm this explanation.     

Excess Thermodynamic Properties of Binary Liquid Mixtures Containing N,N -Dimethylacetamide with Some Alkan-1-Ols (C 1 -C 6 ) At 298.15 K

Excess molar enthalpies, $ H_m^E $ of N , N -dimethylacetamide + methanol, + ethanol, + propan-1-ol, + butan-1-ol, + pentan-1-ol, and + hexane-1-ol have been determined at 298.15 K and atmospheric pressure using a Parr 1455 solution calorimeter. While the excess molar enthalpies are negative for methanol and ethanol mixtures, those for propan-1-ol, butan-1-o1, pentane-1-ol, and hexan-1-ol mixtures are positive over the entire range of composition of N , N -dimethylacetamide. The $ H_m^E $ at around x , 0.5 follow the order: methanol<ethanol<propan-1-ol<butan-1-ol<pentan-1-ol<hexan-1-ol. The results are explained in terms of the self-association exhibited by the alkan-1-ols and the formation of aggregates between unlike molecules through OHO hydrogen bonding. The experimental results for mixtures are well represented by the Redlich - Kister equation.     

Excess enthalpies and (vapour + liquid) equilibrium data for the binary mixtures of dimethylsulphoxide with ketones

Excess enthalpies (H^E), at ambient pressure and T = 298.15 K, have been measured by using a solution calorimeter for the binary liquid mixtures of dimethyl sulphoxide (DMSO) with ketones, as a function of composition. The ketones chosen in the present investigation were methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), and cyclohexanone (CH). The H^E values are positive over the entire composition range for the three binary mixtures. Furthermore, the (vapour + liquid) equilibrium (VLE) was measured at 715 Torr for these mixtures, of different compositions, with the help of Swietoslawski-ebulliometer. The experimental temperature-mole fraction (t-x) data were used to compute Wilson parameters and then used to calculate the equilibrium vapour-phase compositions as well as the theoretical points for these binary mixtures. These Wilson parameters are used to calculate activity coefficients (γ) and these in turn to calculate excess Gibbs free energy (G^E). The intermolecular interactions and structural effects were analyzed on the basis of the measured and derived properties.     

Excess molar enthalpies of R-fenchone + propan-1-ol or +propan-2-ol. Modeling with COSMO-RS and UNIFAC

In this paper, experimental excess molar enthalpies for the binary mixtures of R-fenchone with propan-1-ol or propan-2-ol, at four temperatures (283.15, 298.15, 313.15 and 328.15) K and atmospheric pressure are reported over the entire composition range. They have been fitted to the Redlich–Kister equation at each temperature. Excess molar enthalpies are positive in all cases, being greater for the mixture with propan-2-ol than for the mixture with propan-1-ol. These positive values of the excess enthalpy suggest the predominance of the effect due to hydrogen bond breaking over the interaction between dissimilar molecules in the mixture. Finally UNIFAC (Dortmund) method and the Quantum Continuum Method COSMO-RS have been used to predict the excess molar enthalpies. Better predictions are obtained in the case of UNIFAC model.