Thermodynamic properties of liquid mixtures containing 1,3-dioxolane and anilines: Excess molar volumes, excess molar enthalpies, excess Gibb's free energy and isentropic compressibilities changes of mixing
Introduction
Non-ideality of liquid mixtures has been attributed [1] to either physical intermolecular force or to chemical reaction occurring between the components of liquid mixtures. The process of mixture formation may trigger inter and intramolecular changes in either one or all the components in liquid mixtures which in turn be reflected in their thermodynamic properties like excess molar volumes, excess molar enthalpies, excess Gibb's free energy, etc. In recent studies [2], [3], [4], [5], [6] topology of the constituents of binary or ternary mixtures has been employed to predict excess molar volumes, excess molar enthalpies and isentropic compressibility changes of mixing. An attempt has also been made to employ topology of a molecule to predict excess Gibb's free energy of binary mixture. In continuation of our studies [7], [8] on mixtures containing 1,3-dioxolane, we report here excess molar volumes, excess molar enthalpies, isentropic compressibilities changes of mixing and excess Gibb's free energy of 1,3-dioxolane (i) + aniline or N-methyl aniline or o-toluidine (j) binary mixtures.
Section snippets
Experimental
1,3-Dioxolane (D) (Fluka, 99 mol.%), aniline (A) (Fluka, 99 mol.%), N-methyl aniline (MA) (Fluka, 98 mol.%), o-toluidine (OT) (Fluka, 99 mol.%) were purified by standard methods [9]. The purities of the purified liquids were checked by measuring their densities [recorded in Table 1] using bicapillary pycnometer at 298.15 ± 0.01 K and these agreed to within ±0.05 kg m−3 with their literature values [9], [10]. Excess molar volumes, VE for the binary mixture were measured dilatometrically as described
Results
Excess molar volumes, VE, excess molar enthalpies, HE, and speeds of sound, u data of D (i) + A or MA or OT (j) binary mixtures measured as a function of composition at 308.15 K are recorded in Table 2, Table 3, Table 4 respectively. The isentropic compressibilities, κS for various (i + j) mixtures were determined from their speeds of sound data using relation:
The densities, ρij of binary mixtures were evaluated from their excess molar volumes data by employing Eq. (2)
Discussion
We are unaware of any VE, HE, and GE data of the studied (i + j) mixtures with which to compare our results. VE, HE, and GE data of D (i) + A or MA or OT (j) mixtures are negative over entire composition range. While HE and data for an equimolar mixture vary in the order: MA > OT > A; VE data vary as MA > A ≅ OT. However GE data for the investigated mixtures at an equimolar composition vary in the order: A > OT > MA respectively.
At the simplest qualitative level, HE data of these mixtures can be
Excess molar volumes
According to Graph theory [26], excess molar volumes, VE for a binary (i + j) mixture is given bywhere xi is the mole fraction of component (i).(3ξi), (3ξi)m (i = i or j), etc. are the connectivity parameters of the third degree of a molecule in pure and mixed state and are defined by Eq. (8)where , etc. have the same significance as described elsewhere [27]. (3ξi) or (3ξi) m (i = i or j) for the various of constituents, etc.
Acknowledgements
The authors are thankful to the Head, Department of Chemistry and authorities of Maharshi Dayanand University, Rohtak, for providing research facilities.
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