Volumes of mixing ofn-alkanenitriles withn-alkanes: Interpretation through the Prigogine-Flory-Patterson theory

We present in this work the results of measurements of excess volumes of mixing V ^E at 30°C over the whole composition range for sixteen mixtures of n-hexanenitrile, n-octanenitrile, n-decanenitrile, and n-dodecanenitrile mixed individually with n-heptane, n-decane, n-tridecane, and n-hexadecane. The experimental values of V ^E show a regular pattern of behavior for the four sets of binary systems. In each group of mixtures for a given n-alkanenitrile, the magnitude of V ^E decreases as the n-alkane chain-length decreases. For mixtures containing a common n-alkane, V ^E decreases with increasing n-alkanenitrile chain-length. In order to explain the observed behavior, we have used the Prigogine-Flory-Patterson theory, which divides V ^E into three different contributions. The agreement between the theoretical and experimental V ^E is reasonable for the systems studied.     

Volumes of mixing of pyridine bases withn-alkanes: Comparison with the prigogine-flory-patterson theory

The excess molar volumes of binary mixtures pyridine and -picoline + C₆–C₁₀ n-alkanes have been measured at 25°C over the whole composition range. For pyridine + n-hexane and + n-heptane and also -picoline + n-hexane and n-heptane V ^E has an S-shaped behavior and is positive at low concentrations of the base. For the systems pyridine + n-octane + n-nonane + n-decane and -picoline + n-octane, n-nonane, and n-decane V ^E is positive. The Prigogine-Flory-Patterson theory has been fitted to our results.     

Excess molar volumes of 2-methylethylbenzene with benzene,methylbenzene or ethylbenzene at various temperatures

Excess molar volumes of benzene or methylbenzene + 2-methylethylbenzene at 25, 35 and 45°C and of ethylbenzene + 2-methylethylbenzene at 25°C have been determined from density measurements using a vibrating tube densimeter. Experimental V _m ^E values have been compared with calculated values based on the Flory theory.List of Symbols p _i characteristic pressure of pure component - reduced temperature of pure component - V ^E excess molar volume - V _i ^* characteristic volume of pure component - reduced volume of mixture - reduced volume of pure component i - X ₁₂ interaction parameter in Flory's theory - site fraction of component 2 - segment fraction of component 2     

Topological investigations of molar excess volumes of quinoline with alkanols

Excess volumes V ^E of binary liquid mixtures of quinoline with alkanols have been determined from densities at 30°C as a function of composition. The excess volumes are negative over the whole mole fraction range for all the mixtures and decrease with increasing length of alkanol (C₁–C₁₀). The V^E data have been analyzed in terms of an approach which uses graph theoretical connectivity parameters of the third degrees for two components. The analysis gives information regarding associated species in the pure state and in the mixture. It is suggested that, in the mixture state, no change occurs in the association of alkanols.     

Molecular interaction study through experimental and theoretical volumetric,transport and refractive properties of N-ethylaniline with aryl and alkyl ethers at several temperatures

To investigate the molecular interaction study between secondary amine with aryl and alkyl ether, we report densities, speeds of sound, viscosities and refractive indices of N-ethylaniline (NEA) with aryl (anisole, phenetole) and alkyl (tert-butyl methyl ether) ether over the entire composition regime and in the temperature range of 293.15–323.15 K at 5 K intervals. Various excess and transport properties were derived from the experimental data and the excess parameters were fitted to the Redlich–Kister polynomial equation using multiparametric non-linear regression analysis to derive the binary coefficients and to estimate the standard deviation. Molecular interactions between the unlike molecules were analysed through dipole–dipole interactions, cross-association between the components of the mixtures and H-bond formation. Viscosity and refractive index of the mixtures were predicted through several empirical equations and compared with the experimental results. Prigogine–Flory–Patterson statistical theory was used to predict the excess molar volume results.     

Excess molar volumes ofn-alkanes-thiophene mixtures at 25°C

The excess molar volumes of binary mixtures of n-hexane, n-octane, n-decane, n-dodecane, and n-hexadecane with thiophene have been measured at 25°C over the whole mole fraction range. All the experimental values, except those for n-hexane-thiophene in the thiophene rich region, are positive. The Flory theory was used to determine the influence of molecular contact sites on the excess volumes. A new calculation procedure has been suggested by introducing a new parameter S. This method greatly improved the theoretical results.     

Excess volumes of isomeric butanols with di-n-butyl ether

The excess volumes of four isomeric butanols with di-n-butyl ether were determined at 30°C. The isomeric effect was distinctly observed in the excess volume profiles. 1-Butanol and 2-methyl-l-propanol systems exhibited negative excess volumes throughout the concentration range. The 2-butanol system had positive excess volumes up to 0.9 mol fraction of alcohol after which it became negative, while the 2-methyl-2-propanol system exhibited positive excess volumes throughout the concentration range. NCL Communication No. 4678     

Volumes of mixing and theP * effect: Part I. Hexane isomers with normal and branched hexadecane

The Prigogine-Flory theory of solution thermodynamics has been used to interpret molar excess volume data, V ^E , for two series of alkane mixtures: the five isomers of hexane mixed with normal hexadecane (Data from Reeder, et al.) and the five hexane isomers mixed with a highly branched hexadecane isomer, 2,2,4,4,6,8,8-heptamethylnonane (this work). Values of V ^E are negative and similar for both series, but vary considerably with the hexane within a series. According to the theory, V ^E contains a P^* contribution not found in the excess enthalpy and entropy, which depends strongly on the internal pressures and the derived P^* parameters of the components. Values of V ^E are well predicted for both series, the variation of V ^E corresponding to the different internal pressures or P^* parameters of the hexanes.     

Volumes of mixing and theP * effect: Part II. Mixtures of alkanes with liquids of different internal pressures

The Flory theory of solution thermodynamics is used to predict exess volumes for systems containing a series of n-alkanes mixed with liquids of higher P^* parameter and internal pressure, i.e., cyclopentane, cyclohexane, carbon tetrachloride, benzene and dioxane as well as of lower P^*, i.e., decamethyltetrasiloxane. Trends of V ^E , e.g. changes of sign with alkane carbon number are well predicted and indicate the importance of the P^* contribution in V ^E . Mixtures of hexane isomers with liquids of much higher P^* typically have large excess enthalpies through zero as an S-shaped curve against composition which is negative on the side of the high P^* component. This behaviour is interpreted as arising from increasingly large negative P^* contributions in V ^E .     

Study of the binary mixtures of {monoglyme + (hexane,cyclohexane, octane,dodecane)} by ECM-average and PFP models

Excess molar volumes and excess permittivity of binary mixtures involving monoglyme and alkanes, such as n-hexane, cyclohexane, n-octane and n-dodecane, were calculated from density and relative permittivity measurements for the entire composition range at several temperatures (288.15, 298.15 and 308.15) K and atmospheric pressure. The excess permittivity was calculated on the basis of a recent definition considering the ideal volume fraction. Empirical equations for describing the experimental data in terms of temperature and concentration are given. The experimental values of permittivity have been compared with those estimated by well-known models from literature. The results have indicated that better predictions are obtained when the volume change on mixing is incorporated in these calculations. The contribution of interactions to the excess permittivity was analysed by means of the ECM-average model. The Prigogine–Flory–Patterson (PFP) theory of the thermodynamics of solutions was used to shed light on the contribution of interactions to the excess molar volume. The work concludes with an interpretation of the information given by the theoretical models and the behaviour of both excess magnitudes.     

Excess molar volumes of 1-nonanol withn-heptane at 25, 35 and 45°C1

The excess molar volumes V _m ^E at atmospheric pressure and at 25, 35 and 45°C for binary mixtures of 1-nonanol, with n-heptane have been obtained over the whole mole fraction range from densities measured with a vibrating-tube densimeter. The measurements at 25°C were extended to high dilution of 1-nonanol. The V _m ^E are sigmoid for the three temperatures, with a small maximum at low mole fractions of the alkanol. The absolute values of V _m ^E increase with temperature from 25 to 45°C.Communicated in part at the 4^th International Conference on Thermodynamics of Solution of Non-Electrolytes, Santiago de Compostela, Spain (1989).     

Molar and Partial Molar Excess Volumes of Benzene in Methyl Ester Solutions at 25°C

Molar and partial molar excess volumes of mixtures of benzene with several methyl esters (from methanoate to decanoate) were determined, over the whole concentration range, at 25°C and atmospheric pressure from experimental densities and correlated by a suitable equation. The applicability of the Flory and Priggogine–Flory–Pattersort models for predicting molar excess volumes is tested. The calculated values with Flory and Priggogine–Flory–Patterson are similar and agree poorly with the experimental data.     

Excess volumes and viscosities of mixtures of dimethylsulfoxide with normal alcohols at 40°C

Excess volumes and viscosities have been determined for DMSO + n-hexanol, + n-heptanol, + n-octanol, and + n-decanol at 40°C. The excess partial molar volumes V ₁ ^E , changes in viscosities , the parameter d of the Grunberg and Nissan expression, and excess Gibbs free energies of activation of flow G _* ^E have been calculated from the experimental data. All the excess volumes are positive over the whole composition range, with V ^E increasing with the length of the alkanol chain. V ^E results are discussed in terms of disruption of alkanol multimers, weakening of interactions between DMSO molecules, influence of interactions between components, and structural effects. The V ^E data have also been analyzed using the Prigogine-Flory-Patterson expression which separates V ^E into three contributions. Correlation is also observed between the sign of and V ^E for all the mixtures studied.     

Excess molar volumes and enthalpies for the binary systems propyl propanoate + o-xylene, m-xylene, and p-xylene at 298.15 K

This paper reports excess molar enthalpies, H_m^E, and excess molar volumes, V_m^E, of the binary systems {propyl propanoate + o-xylene}, {propyl propanoate + m-xylene} and {propyl propanoate + p-xylene} at the temperature 298.15 K and atmospheric pressure, over the whole composition range. V_m^E was calculated from the experimental measurement of the corresponding densities, while H_m^E was measured directly. The excess magnitudes were correlated to a Redlich-Kister type equation. Finally, we will discuss the results of the three mixtures studied here and by comparison with other binary systems containing propyl propanoate and a benzene-based compound previously published.     

Excess volumes of the binary mixtures of trichloroethylene withn-alcohols at 30 and 40°C

Volumes of mixing binary systems formed by trichloroethylene with n-alcohols (1-propanol, 1-butanol, 1-pentanol, 1-hexanol, 1-heptanol, and 1-octanol) were measured as a function of composition at 30 and 40°C, by dilatometric measurements. All the systems show a change of sign for V ^E from negative to positive as the mole fraction trichloroethylene increases at both temperatures The positive value of the excess volumes increase as carbon chain length increases. The results are explained in terms of depolymerization of hydrogen bonded alcohol aggregates and weak hydrogen-bonding interaction of the type Cl-H–O between unlike molecules.     

Excess molar volumes of methyl tert-butyl ether with chloroalkanes at 30°C

Excess molar volumes are reported for binary mixtures of methyl tert-butyl ether with trichloromethane, tetrachloromethane, 1,2-dichloroethane, 1,1,2-trichloroethane, 1,1,2,2-tetrachloroethane, or 1,1,1,2,2-pentachloroethane at 30°C over the entire composition range of the mixtures. Excess volumes for all the mixtures are found to be negative. A qualitative interpretation of the results in terms of O–H–C and Cl–O interactions is presented. The Prigogine-Flory-Patterson theory has been used to analyze the results.     

Excess enthalpies and apparent molar volumes of aqueous solutions of crown ethers and cryptand(222) at 25°C

The enthalpies of dilution and densities of aqueous solutions of 12-crown-4, 15-crown-5, 18-crown-6, 1,10-diaza-18-crown-6 and cryptand (222) were measured at 25°C. The excess enthalpies and enthalpic coefficients of solute-solute interactions were calculated by the McMillan-Mayer theory formalism. Values for the apparent molar volumes at infinite dilution were determined by extrapolation. The contributions of the-CH₂CH₂O-group to values of h₂ and to the limiting partial molar volume were calculated for the series of crown ethers studied. It is concluded that the hydrophobic hydration and the hydrophobic solute-solute interaction are predominant in the solutions investigated.