Speeds of sound, isentropic compressibilities, viscosities, and excess molar volumes of binary mixtures of alkanoates with tetra- and trichloromethanes at 303.15 K
Introduction
As a part of our systematic studies on the thermodynamic, transport, and acoustic properties of liquid mixtures containing alkyl alkanoates, in the previous papers [1], [2], [3], [4], the speeds of sound, isentropic compressibilities, viscosities and excess molar volumes for binary mixtures of methyl acetate, ethyl acetate, pentyl acetate and iso-pentyl acetate with chloroalkanes have been reported. The results were explained by considering specific interactions between acetate and chloroalkane. As an extension of our studies, in this paper we report speeds of sound, isentropic compressibilities, viscosities, and excess molar volumes for binary mixtures of diethyl malonate (DEM), diethyl bromomalonate (DEBrM), and ethyl chloroacetate (EClA) with tetrachloromethane (CCl4) and trichloromethane (CHCl3). The viscosity measurements will also provide a test of various empirical equations to correlate viscosity data of binary mixtures in terms of pure component properties.
Section snippets
Experimental
The speeds of sound u in pure liquids and in binary mixtures were measured with multi-frequency ultrasonic interferometer supplied by Mittal Enterprise, New Delhi. In the present work, a steel cell fitted with a quartz crystal of 2 MHz-frequency was employed. The viscosities η were measured with a modified suspended-level Ubbelohde viscometer [5]. The viscometer was designed so as to reduce surface tension effects to negligible value [6]. A water-circulating thermostat with an accuracy of ±0.02 K
Results
The results for the speeds of sound u, densities ρ, isentropic compressibilities κS, and viscosities η are given in Table 2. VE for each mixture was calculated from equationκSE was calculated from the relation recommended by Benson and Kiyohara [17] and Douheret et al. [18]in which the Vi, αi and Cp,i are respectively, the molar volume, isobaric thermal expansion coefficient and molar isobaric heat capacity of pure component i and ϕ
Correlating equations
Apart from expressing η as a polynomial fit, several semi-empirical relations have been proposed to estimate the dynamic viscosity η of liquid mixtures in terms of pure-component data [14], [21]. We have examined equations proposed by Grunberg and Nissan [22], Tamura and Kurata [23], Hind, McLaughlin, and Ubbelohde [24], Katti and Chaudhri [25], McAllister [26], Heric and Brewer [27] and Auslaender [28].The Grunberg-Nissan phenomenological equation [22] reads
Alkanoate + tetrachloromethane
The dependence of VE, κSE, Δη and ΔG*E on composition x1, is shown in Fig. 1, Fig. 2, Fig. 3, Fig. 4. Previously published results of ethyl acetate (EA) + CCl4 [1], [2], [29] are also included in Fig. 1, Fig. 2, Fig. 3, Fig. 4 for the purpose of comparison with EClA + CCl4. It can be seen from Fig. 1, Fig. 2, Fig. 3, Fig. 4 that the values of VE, κSE, Δη, and ΔG*E for alkanoate + CCl4 mixtures are highly dependent on the type of components involved and curves are unsymmetrical. The values of VE
Application of CFT and FLT
The speed of sound u from the Schaaffs’ collision factor theory (CFT) [36] and the Jacobson's intermolecular free length theory (FLT) [37] have also been estimated for the present binary mixtures. The pertinent relations in these calculations and their theoretical basis have been outlined several times [36], [37], [38], [39], [40], [41]. Only brief mention will be made here. In terms of the CFT [38], [39] the speed of sound u in pure liquid and mixture is related towhere u∞ = 1600 m s−1, S
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