Ternary Excess Molar Enthalpies Research Articles

Excess molar enthalpies of ternary and constituent binary systems {1,2-dichloropropane+2-propanol+2-butanol} at T=298.15 K

Ternary excess molar enthalpies at T=298.15 K and P=101.3 kPa for the system of {1,2-dichloropropane+2-propanol+2-butanol} and their constituent binary systems {1,2-DCP+2-propanol}, {1,2-DCP+2-butanol}, and {2-propanol+2-butanol} have been measured over the whole composition range using an isothermal micro-calorimeter with flow-mixing cell. All of the binary and ternary systems, including three pseudobinary systems, show endothermic behavior except for the binary mixture {2-propanol+2-butanol}, which shows small exothermicity. The Redlich-Kister equation was used to correlate the binary Hm, ijE data, and the Morris equation to correlate the ternary Hm, 123E data. Comparisons between the Morris and Radojkovi equations for the prediction of Hm,123E have been also made. The experimental results have been qualitatively discussed in terms of self-association, isomeric effect and chain length among molecules.

Calorimetric study of the mutual effect in binary and pseudobinary mixtures of some aliphatic alcohols and some cyclic ethers

Excess molar enthalpies, for (methanol+ethanol+oxane) and (methanol+ethanol+1, 4-dioxane) mixtures at 298.15K and atmospheric pressure were measured experimentally. The experimental results were correlated with a polynomial equation to estimate the coefficients. The pseudobinary excess molar enthalpies for all systems under investigation are found to be positive over the entire range of compositions. The experimental results were explained according to the UNIQUAC associated solution model. The ternary excess molar enthalpies, Hm,123E for {methanol (1)+ethanol (2)+1, 4-dioxane (3)} system are higher than that of {methanol (1)+ethanol (2)+oxane (3)} system. Also the ternary excess molar enthalpies Hm,123E in the different methanol compositions are in the order: 25% methanol>that 50% methanol>75% methanol.

Ternary excess molar enthalpies of (1-propanol + 2-propanol + 1,4-dioxane) mixture at 298.15 K

Ternary excess molar enthalpies for (1-propanol + 2-propanol + 1,4-dioxane) mixture have been measured with a flow calorimeter at T = 298.15 K and atmospheric pressure. Constant contours for the ternary experimental results were calculated by a polynomial equation. Further, the results have been compared with those calculated from a UNIQUAC formalism taking into consideration the molecular self- and cross-association of two alcohols and the solvation among the alcohols and 1,4-dioxane. The results predicted by using binary parameters obtained from the corresponding binary results alone are in good agreement with the experimental values.

Excess Molar Enthalpies of Ternary Mixtures of Ethanol + 1-Propanol + Tetrahydropyran or 1,4-Dioxane at 298.15 K

Excess molar enthalpies for the (ethanol + 1-propanol + tetrahydropyran) and (ethanol + 1-propanol + 1,4-dioxane) ternary mixtures and their binaries (ethanol + tetrahydropyran) have been measured by a flow microcalorimeter at 298.15 K and ambient pressure. The experimental results are correlated with a polynomial equation. The results have been compared with those calculated from a UNIQUAC associated-solution model. This model considers the self-association of like alcohols, cross-association of unlike alcohols, and solvation between alcohols and tetrahydropyran or 1,4-dioxane. The model with the association constants, solvation constants, and binary information alone could satisfactorily represent the ternary excess molar enthalpies.

Excess molar enthalpies of ternary mixtures of (methanol, ethanol + 2-propanol + 1,4-dioxane) at T=298.15 K

Ternary excess molar enthalpies for the { x 1CH 3OH + x 2 i-C 3H 7OH + (1− x 1− x 2) c-C 4H 8O 2} and { x 1C 2H 5OH + x 2 i-C 3H 7OH + (1− x 1− x 2) c-C 4H 8O 2} mixtures have been measured by a flow microcalorimeter at T=298.15 K and ambient pressure. The experimental results are correlated with a polynomial equation and used to construct constant excess enthalpy contours. Furthermore, the results have been compared with those calculated from a UNIQUAC associated-solution model. This model considers the self-association of like alcohols, multicross-association of unlike alcohols, and solvation between alcohols and 1,4-dioxane. The model with the association constants, solvation constants, and binary information alone predict the ternary excess molar enthalpies satisfactorily.

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.

Excess Molar Enthalpies of Propyl Propanoate + 1-Hexanol + Benzene at the Temperatures 25 °C and 35 °C

As a part of our calorimetric studies, we have measured the excess molar enthalpies of the ternary system {(x1)propyl propanoate + (x2)1-hexanol + (1 − x1 − x2)benzene} and of their corresponding binary mixtures at 25 °C and 35 °C and atmospheric pressure, over the whole composition range. The excess molar enthalpies were obtained by means of a Calvet microcalorimeter. The excess molar enthalpies for the binary mixtures were fitted to a Redlich−Kister variable-degree polynomial, and the ternary excess molar enthalpies were adequately correlated by the Cibulka equation. The results obtained for the ternary mixture were used to test the empirical methods of Kohler; Jacob and Fitzner; Colinet; Tsao and Smith; Toop; Scatchard et al.; and Hillert. These methods predict excess properties of the ternary mixtures from those of the involved binary mixtures.

Excess Molar Enthalpies for Ethanol + 2-Propanol + Methyl tert-Butyl Ether and 1-Propanol + 2-Propanol + Methyl tert-Butyl Ether at the Temperature of 298.15 K

Ternary excess molar enthalpies for the ethanol + 2-propanol + methyl tert-butyl ether (MTBE) and 1-propanol + 2-propanol + MTBE systems have been measured by a flow microcalorimeter at 298.15 K and ambient pressure. The pseudobinary excess molar enthalpies are positive over the whole range of composition. The ternary experimental results are correlated with a polynomial equation. The results have been compared with those calculated from a UNIQUAC associated-solution model taking into account the self-association of alcohols as well as the solvation between unlike alcohols and alcohols with MTBE using only binary parameters.

Excess molar enthalpies of ternary mixtures formed by methanol and methyl tert-butyl ether with ethanol or 1-propanol at 298.15 K

Ternary excess molar enthalpies for (methanol+ethanol+methyl tert-butyl ether (MTBE)) and (methanol+1-propanol+MTBE) mixtures have been measured with a flow microcalorimeter at T=298.15 K and atmospheric pressure. Constant contours for the ternary experimental results were calculated by a polynomial equation. Further, the results have been compared with those calculated from a UNIQUAC associated-solution model taking into account the molecular self- and cross-association of two alcohols and the solvation among the alcohols and MTBE. The results predicted by using binary parameters obtained from the corresponding experimental binary results alone are in good agreement with the experimental values.

Ternary excess molar enthalpies of alcohols with methyl t-butyl ether at T = 298.15 K

Ternary excess molar enthalpies HEm at 298.15 K and atmospheric pressure measured in a flow microcalorimeter are reported for the methanol+2-propanol+methyl t-butyl ether (MTBE) and ethanol+1-propanol+MTBE systems. The ternary results have been correlated by means of a polynomial equation and used to construct constant excess enthalpy contours. Furthermore, the results have been compared with those calculated from a UNIQUAC associated-solution model taking into account molecular association of alcohols and solvation between unlike alcohols and alcohols with MTBE using only binary information.

Association model of fluids. Phase equilibria and excess enthalpies in acid mixtures

The binary vapor-liquid and liquid-liquid equilibria and molar excess enthalpies of alkanoic acid mixtures are correlated well using a new associated-solution model whose equilibrium constants are defined in terms of the volume fractions of chemical species and using association parameters for dimerization of acid molecules calculated from the vapor pressures of the pure acids. The model shows a good performance in predicting ternary vapor-liquid equilibria of the acetic acid + toluene + n-heptane system, ternary liquid-liquid equilibria of alkanoic acid mixtures including water and a non-associated component, and ternary excess molar enthalpies of the acetic acid + methanol + tetrachloromethane system from only binary parameters.

Correlation of ternary excess molar enthalpies for mixtures containing an alkanol and two active non-associated components using a mole-fraction association model

Excess molar enthalpies are reported for methanol + toluene + cyclohexane, measured with an isothermal dilution calorimeter at 25°C. The experimental results have been correlated with a mole-fraction association model having binary and ternary parameters. The workability of the proposed model has been confirmed satisfactorily for many ternary alcohol mixtures.

Application of the uniquac associated-solution model to alkanoic acid + alkanol and ifalkanol + hydrocarbon mixtures

The UNIQUAC associated-solution model has been applied to reproduce vapour-liquid equilibria and excess molar enthalpies for binary mixtures containing one alkanoic acid and one alkanol and then to predict ternary excess molar enthalpies for acetic acid + methanol + tetrachloromethane. Furthermore, the model has been modified to include additional parameters in order to obtain a better correlation of vapour-liquid equilibria of strongly non-ideal mixtures involving at least one alkanol. The calculated results agree well with the experimental values for many systems studied.

Experimental and predicted excess enthalpies of the 2,2,2-trifluoroethanol–water–tetraethylene glycol dimethyl ether ternary system using binary mixing data

Excess enthalpies of the ternary mixture 2,2,2-trifluoroethanol–water–tetraethylene glycol dimethyl ether and the corresponding binary mixtures at 298.15 K have been measured using a standard Calvet microcalorimeter. Wilson, NRTL, UNIQUAC and Wang et al. models have been used to correlate the binary excess enthalpies and, using the parameters obtained, to predict ternary excess molar enthalpies, HE. Several empirical equations predicting ternary-mixture properties from the binary-mixing data have been also examined.

Thermodynamics of associated solutions. Correlation of ternary excess molar enthalpies for aniline + alkanol + benzene or acetone mixtures using the UNIQUAC associated-solution model

Ternary excess molar enthalpies are reported for 1-propanol + aniline + acetone at 25°C. The UNIQUAC associated-solution model with ternary parameters is used to correlate ternary excess molar enthalpies for aniline + alkanol + benzene or acetone mixtures. The model gives appreciably smaller deviations between the calculated and experimental results than those obtained using polynomial equations.

Enthalpies of mixing for the n-pentane + methylacetate + dichloromethane system at 298.15 K and their prediction with the UNIFAC model

New experimental data of the excess molar enthalpies at 298.15 K for the ternary system n-pentane+methylacetate+dichloromethane, together with corresponding data for the constituent binary mixtures, are presented. Different expressions from the literature are used to predict excess enthalpies from the corresponding binary data. The empirical correlation of Nagata and Tamura (J. Chem. Eng. Data, 33 (1988) 283) gives the best results for this system. The UNIFAC group contribution is applied to predict ternary excess molar enthalpies which are compared with the experimental data.

Thermodynamics of associated solutions. Prediction of excess molar enthalpies of acetone + bromoform + saturated hydrocarbon mixtures using a chemical model

A chemical model based on mole-fraction statistics is used to predict ternary excess molar enthalpies for acetone + bromoform + saturated hydrocarbon mixtures, in which the hydrocarbon is cyclohexane, n-hexane, n-heptane, or n-decane, from binary information alone. The model used gives significantly smaller deviations between the calculated and experimental results than the chemical models proposed by Singh et al.

Prediction of ternary excess molar enthalpies for n-butylamine + 1,4-dioxane + acetonitrile from binary data alone

A chemical association model based on mole fraction statistics is used to predict the ternary excess molar enthalpies of the n-butylamine + 1,4-dioxane + acetonitrile system using only binary parameters derived from excess molar enthalpy data for its three constituent binary systems. The model assumes that the self-association of n-butylamine and acetonitrile, the solvation between unlike molecules and the binary non-specific molecular interactions between the components are given by the nrtl equation.

Thermodynamics of liquid mixtures of acids. Vapour- liquid equilibria and excess molar enthalpies of alkanoic acid mixtures with alcohols

Vapour-liquid equilibria and excess molar enthalpies of binary solutions of methanoic acid, ethanoic acid, propanoic acid, and butanoic acid with methanol, ethanol, propanols, and 1-butanol were calculated using the uniquac associated-solution model, which takes into account the homo-association of like molecules and the hetero-association of unlike molecules. Ternary excess molar enthalpies of ethanoic acid + methanol + tetrachloromethane were predicted from the same model with binary parameters. The calculated results agree well with the experimental values.

Thermodynamics of associated solutions: Prediction of ternary excess molar enthalpies of alcohol mixtures containing an active non-associating component

Ternary excess molar enthalpies of 1-propanol+triethylamine + n-heptane, 1-propanol + 1-hexanol + 3-pentanone and 1-propanol + 1-heptanol + 3-pentanone have been predicted using the uniquac associated-solution model with binary parameters alone. For 1-propanol + triethylamine + n-heptane, the uniquac associated-solution model gives better predicted results than those obtained from the eras model of Heintz and the nrtl equation. For the two other ternary systems, the uniquac associated-solution model is superior to the group-contribution model of Nitta-Chao.