Estimation of Thermodynamic Properties of Binary Liquid Mixtures on the Basis of Statistical Mechanical Theories (original) (raw)
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Thermodynamic Study of Binary Liquid Mixtures of Benzene and 1,2- dichloroethane at T = 303.15 K
International Journal of Thermodynamics, 2013
Thermodynamic studies like density (ρ), specific gravity, ultrasonic speed (u) and excess molar volume () and excess enthalpy () of binary liquid mixtures of benzene + 1,2-dichloroethane have been carried out over the different range of composition at 303.15 K. Thermodynamic parameters like isentropic compressibility (k s) intermolecular free length (L f) and relative association (R A) have been calculated from density and ultrasonic speed measurement. The excess thermodynamic functions have been fitted to the Redlich-Kister polynomial equation. The experimental ultrasonic speeds have been analyzed in terms of Jacobson Free Length Theory (FLT), Schaaff's Collision Factor Theory (CFT), Nomoto's relation, and Van Dael's ideal mixture relation. Intermolecular Free Length (L f) and available volume (V a) have been calculated from FLT, CFT and thermoacoustic approach. It is observed that density and specific gravity increases and ultrasonic speed, isentropic compressibility and intermolecular free length decreases with the mole fraction of 1,2-dichloroethane. It is found that intermolecular interaction present between binary liquid mixtures were stronger than pure solvent-solvent interactions. Observed negative values of excess molar volume and positive value of molar excess enthalpy confirm the presence of specific chemical attractive force of interactions between the two binary liquid mixtures.
Acta Physica Polonica A, 2010
Seven hard-sphere models and Flory's statistical mechanical theory have been applied to evaluate thermal expansion coefficient of ternary liquid systems involving dimethyl sulfoxide with phenol/o-cresol in carbon tetrachloride at 293.15, 303.15 and 313.15 K. The results thus obtained are compared with the experimental values of thermal expansivity. The relative applicability of all these approaches to the present investigation has been checked and discussed. The excess values of thermal expansivity have also been calculated and utilized to study the presence and strength of intermolecular interactions in the ternary liquid systems under investigation.
2015
The observed experimental parameters such as density (ρ), and ultrasonic velocity (U) of butanol, toluene and pyridine were measured over the entire range of composition at different temperatures 303,313,323 K. The observed experimental data have been utilized to evaluate some of the excess thermo-acoustical parameters such as excess volume (V E ), excess adiabatic compressibility (βa E ) and excesses free length (L f E ). Thermo-acoustic parameters are also calculated theoretically by applying Jacobson's free length theory and Kalidoss revised free length theory, statistical Chi-square (χ 2 ) test applied to both the theories, applicability of liquid theories
The thermophysical properties such as density and viscosity of binary liquid mixtures were determined experimentally over the entire composition range at 303.15K, 308.15K and 313.15K. The experimentally determined thermophysical properties of the binary liquid mixtures were used to calculate the excess molar volume V E and viscosity deviations Δη with two hydrocarbons bromobenzene and ethylbenzene. The excess thermophysical properties of liquid mixtures provide additional information regarding molecular interactions. The calculated excess volumes, V E and deviations in viscosities, Δη exhibited positive and negative values respectively over the whole range of composition in both binary systems. The Krishnan-Laddha and Jouyban-Acree Models were used to correlate deviations in viscosities, Δη, to derive the binary coefficients and standard deviations of these systems. The fitted outcomes and the calculated data clearly indicated that weak interactions present in two mixtures. It is mainly because of the number and position of methyl groups existing in these aromatic hydrocarbons. It can be concluded that the data found with the values fitted by the corresponding Krishnan-Laddha and Jouyban-Acree models gives high degree of precision.
International Journal of Engineering Science, 1977
A Hard Sphere Expansion (HSE) conformal solution theory, which is a result of the application of statistical mechanics, is-developed in order to predict the vapor-liquid equilibria properties of multicomponent mixtures. The HSE mixing rules are derived with consideration of the Kihara spherical-core function as the pair potential together with the 3-body potential function. Based on this HSE conformal solution theory, an equation of state for multi-component fluid is developed. In this conformal solution theory perturbation equation of state of pure fluids is used as the reference equation of state. The vapor-liquid equilibria properties of several properly chosen binary and ternary non-polar mixtures are predicted. These mixtures include: argon-krypton, argon-methane, methane-krypton, nitrogen-methane, nitrogen-argon, argon-neopentane, methane-neopentane, methane-perfluoromethane, carbon dioxide-ethylene, carbon dioxide-ethane, nitrogen-argon-0xygen, and nitrogen-argon-methane. The predicted results obtained in the present investigation compare quite favorably with the experimental vapor-liquid equilibria values, Furthermore, the present approach, being a purely molecular theory of fluid mixtures, provides detailed insight into the peculiar behavior of the azeotropic fluid mixture. It is shown that the vapor-liquid equilibria properties of multicomponent fluid systems may be predicted correctly through the present statistical mechanic approach provided that like-and unlike-interaction parameters of the species of the mixtures are known a priori. Generally, the present investigation shows that the use of the molecular theory of fluid mixtures in predicting the mixture properties is very promising. INTRODUCT ION FoR OPTIMUM design of the equipment used in the separation processes, it is necessary to know the phase equilibria and other thermodynamic properties of the mixtures which are to be separated. Until quite recently, there has been little use for the fundamental molecular theories of fluids and fluid mixtures for predicting thermodynamic properties of real fluids, particularly at high pressures and in condensed states[l,2}. This has resulted from two factors; (i) complexity of the fundamental theories of fluids and (ii) the non-convergence of most of these theories in the case of condensed states. As a result, the general practice in phase equilibria and other thermodynamic property predictions has been the use of empirical methods. The basic approach of empirical techniques has been the development of correlations for thermodynamic properties of pure fluids. By the use of empirical mixing rules for the coefficients of pure fluid correlations, with respect to mole fractions, similar correlations for mixtures are developed. S ince the mid-sixties, there has been considerable development in the application of statistical thermodynamics in the predictions of thermodynamic properties of pure fluids and fluid mixtures. These methods, which are collectively termed as perturbation methods, yield excellent results when predicting thermodynamic properties of simple fluids and simple binary fluid mixtures [3-5]. While the perturbation equations of state for pure fluid possess simple forms, the perturbation relations for binary mixtures are rather complex, involving elaborate calculations. The use of the perturbation equations of state for the prediction of properties of multicomponent systems consisting of three components or more is extremely complicated at the present time. As far as the practical applications are concerned, the most successful theories in predicting the equilibrium thermodynamic properties of multicomponent mixtures have been the corresponding states, or conformal solution theories of mixtures [6, 7]. In the development of a conformal solution theory for mixtures, two principles are considered. One is the choice of an accurate equation of state for the reference pure system. The second is the choice of mixing
International Journal of Thermophysics, 2006
Self-consistent calculations of interaction pVT-virial coefficients B 12 (T ), viscosities η mix (T ), and diffusion coefficients D 12 (T ) of binary mixtures of the alkanes C n H 2n+2 (n < 6) are presented. This study is based on the recently developed model of the (n-6) Lennard-Jones temperature-dependent potential (LJTDP) and uses already obtained potential parameters of the pure alkanes as input data. The well-known and simple Lorentz-Berthelot (LB) and the more elaborate Tang-Toennies (TT) mixing rules are applied to the potential parameters of the pure alkanes in order to determine those of the mixtures. The new Hohm-Zarkova-Damyanova (HZD) mixing rule, which is an extension of the TT-mixing rule, is also considered. The HZD takes into account that for the LJTDP model, in general, the repulsive parameter is an independent variable whose value n = 12. As in a recent examination of binary mixtures of globular molecules, the LB-mixing rule is superior to TT-and HZD-mixing rules when calculating equilibrium properties such as B 12 (T ). For the transport properties η mix (T ) and D 12 (T ), the new mixing rule performs slightly better.
International Journal of Thermophysics, 2005
This paper discusses a mathematical model for computing the thermodynamic properties of propane, n-butane, isobutane, and their mixtures, in the fluid phase using a method based upon statistical chain theory. The constants necessary for computations such as the characteristic temperatures of rotation, electronic state, etc. and the moments of inertia are obtained analytically applying a knowledge of the atomic structure of the molecule. The paper presents a procedure for calculating thermodynamic properties such as pressure, speed of sound, the Joule-Thomson coefficient, compressibility, enthalpy, and thermal expansion coefficient. This paper will discuss, for the first time, the application of statistical chain theory for accurate properties of binary and ternary mixtures including propane, n-butane, and isobutane, in their entire fluid phases. To calculate the thermodynamic properties of Lennard-Jones chains, the Liu-Li-Lu model has been used. The thermodynamic properties of the hydrocarbon mixtures are obtained using the one-fluid theory.
International Journal of Engineering Research and Technology (IJERT), 2012
https://www.ijert.org/thermodynamic-properties-of-organic-liquid-mixtures-related-to-molecular-interactions-between-the-components https://www.ijert.org/research/thermodynamic-properties-of-organic-liquid-mixtures-related-to-molecular-interactions-between-the-components-IJERTV1IS8352.pdf In the present paper, thermodynamic properties of organic liquid mixtures related to molecular interactions between the components have been analysed intensively. In addition to that, the present paper also includes a brief discussion on comparative study between the experimental and theoretically calculated values of refractive indices at three temperatures 293, 303 and 313K. The results have been discussed in terms of average percentage deviation (APD).
The Journal of …, 2007
The predictions from a recently reported (J. Chem. Phys. 2004, 120, 6648) two-state association model (TSAM) have been tested against experimental data. The temperature, T, and pressure, p, dependence of the isobaric heat capacity, C p , for three pure alcohols and the temperature dependence at atmospheric pressure of the excess heat capacity, C p E , for four alcohol + ester mixtures have been measured. The branched alcohols were 3-pentanol, 3-methyl-3-pentanol, and 3-ethyl-3-pentanol, and the mixtures were 1-butanol and 3-methyl-3pentanol mixed with propyl acetate and with butyl formate. These data, together with literature data for alcohol + n-alkane and alcohol + toluene mixtures, have been analyzed using the TSAM. The model, originally formulated for the C p of pure liquids, has been extended here to account for the C p E of mixtures. To evaluate its performance, quantum mechanical ab initio calculations for the H-bond energy, which is one of the model parameters, were performed. The effect of pressure on C p for pure liquids was elucidated, and the variety of C p E (T) behaviors was rationalized. Furthermore, from the C p data at various pressures, the behavior of the volume temperature derivative, (∂V/∂T) p , was inferred, with the existence of a (∂V/∂T) p versus T maximum for pure associated liquids such as the branched alcohols being predicted. It is concluded that the TSAM captures the essential elements determining the behavior of the heat capacity for pure liquids and mixtures, providing insight into the macroscopic manifestation of the association phenomena occurring at the molecular level. * Corresponding authors. Phone: (34) (988) 387217 (C.A.C.); (52) (55) 56223520 (M.C.). Fax: (34) (988) 387001 (C.A.C.); (52) (55) 56223521 (M.C.).
Excess thermodynamic properties in liquid binary mixtures
Journal of Raman Spectroscopy, 2008
Excess volumes and adiabatic compressibility have been measured in several binary liquid mixtures to answer the question whether structural information can be gained through the analysis of the concentration dependence of the excess quantities. The obtained results are compared with independent indications from Raman spectroscopy, which is able to probe directly the occurrence and the nature of effective intermolecular interactions. Some doubts have arisen against the usual approach adopted for estimating the excess quantities and about the adequacy of the usual assumptions for the reference ideal behaviours. In particular, it is shown how excess compressibility can result just from statistical effects also in absence of any excess volume contribution. The leading idea is supported by the comparison of the experimental data with the results from a naive model for binary mixtures of hard spheres. The model turns out to be able to produce a very wide spectrum of structural and thermodynamic behaviours depending on the values of its parameters and on the nature (additive or non-additive) of the hard-sphere potential. A discussion is proposed on the re-evaluation of excess thermodynamic data and on their ability in providing direct information on intermolecular interactions.