Studies of Associated Solutions: Evaluation of Thermodynamic Parameters of Blends of 2-Methylaniline and Substituted Ethanols at Various Temperatures

Abstract

Densities (ρ), speeds of sound (u), and viscosities (η) are reported for binary mixtures of 2-methylaniline with substituted ethanols (2-phenylethanol, 2-chloroethanol and 2-aminoethanol) over the entire composition range of mole fraction at T = (303.15–318.15) K and at atmospheric pressure, 0.1 MPa. The excess molar volume, excess isentropic compressibility and deviation in viscosity are calculated from the corresponding experimental densities, speeds of sound and viscosities. The excess properties are correlated using the Redlich–Kister polynomial smoothing equation. Excess partial molar volumes and excess partial molar isentropic compressibilities were calculated for all the binary systems throughout the composition range and also at infinite dilution. The variations in these properties with composition, for all the binary mixtures, suggest that loss of dipolar association, difference in size and shape of the component molecules, dipole–dipole interaction and hydrogen bonding between molecules of 2-methylaniline with 2-phenylethanol, 2-chloroethanol and 2-aminoethanol are involved.

1 Introduction

The study of molecular interactions in mixed solvent systems is of great significance owing to the practical applications of these systems in various technologies, as they provide a wide choice of solutions with appropriate properties. The excess thermodynamic properties of binary liquid mixtures have been very useful for obtaining information on the intermolecular interactions in the systems. The negative or positive deviations from the ideal value depend on the type and extent of the interactions between unlike molecules, as well as on the composition and the temperature [1].

Knowledge of the physico-chemical properties of non-aqueous binary liquid mixtures has relevance in theoretical and applied areas of research and such results are frequently used in the design process (flow, mass transfer or heat transfer calculations) in many chemical and industrial processes. The excess properties derived from these physical property data reflect the physico-chemical behavior of the liquid mixtures with respect to the solution structure and intermolecular interactions between the component molecules of the mixture [2].

This work is part of our program to give information/data for the characterization of molecular interactions between solvents in binary systems [3]. The liquids were chosen for the present study on the basis of their industrial importance. 2-Methylaniline is an important compound used in the manufacturing of dyes and of rubber vulcanization accelerators. It is also used in the fabrication of hypnotic and anesthetic pharmaceuticals and pesticides. On the other hand, 2-chloroethanol is a polar, bi-functional compound, consisting of both a hydroxyl group as a proton donor and halogen atom as a proton acceptor. It is a versatile solvent used in many industrial areas and is also a mutagenic chemical. 2-Aminoethanol is a widely used agent in the carbon dioxide and hydrogen sulfide removal processes. 2-Phenylethanol has found usage in artificial essences and as a base solvent for some flavor compounds.

In the present study, our focus is on the study of liquid mixtures of substituted ethanols with 2-methylaniline because there have been a few studies on these mixtures [4, 5]. It is expected that there will be a significant degree of H-bonding in these binary mixtures because 2-methylaniline and substituted ethanols both have a proton donor and a proton acceptor group [6]. To understand the possible associations between 2-methylaniline and substituted ethanols through –OH···NH and –NH···OH bonds, we report the densities, speeds of sound and viscosities for three binary systems (2-methylaniline with 2-phenylethanol, with 2-chloroethanol, and with 2-aminoethanol) at T = (303.15–318.15) K and under 0.1 MPa pressure. The experimental data has been used to compute the excess volumes (V^E), excess isentropic compressibilities ($\kappa_{S}^{\text{E}}$) and deviations in viscosity (∆η). The results are used to qualitatively discuss specific interactions between unlike molecules.

2 Experimental Methods

2.1 Materials

Chemicals used in the present study are 2-methylaniline (Sigma–Aldrich), 2-phenylethanol (Sigma–Aldrich), 2-chloroethanol and 2-aminoethanol. These chemicals were purchased from S.D. Fine Chemicals Ltd. 2-chloroethanol and 2-aminoethanol chemicals were further purified by standard methods [7, 8] like distillation and fractional distillation under reduced pressure, and only the middle fractions were collected. Before use, the chemicals were stored over 0.4 nm molecular sieves for about 72 h to remove water and gas. The purity of the liquid samples was checked by gas chromatography. The water contents were determined by the Karl–Fischer method. The details of the chemicals and purification methods are presented in Table 1.

Table 1 List of chemicals with details of source, CAS number, purity and water content

2.2 Apparatus and Procedure

All the binary liquid mixtures were prepared by weighing appropriate amounts of the pure liquids on an Afcoset-ER-120A electric balance, using a syringe, in a narrow mouth stoppered bottle. The resolution of electronic balance was ± 0.01 mg while the accuracy of the mole fraction was ± 1 × 10⁻⁴.

Densities and speeds of sound were measured with a digital oscillating Density and Sound Analyzer (DSA 5000 M, Anton Parr, Austria) with a reproducibility of ± 1 × 10⁻⁶ g·cm⁻³ for the density and ± 1 × 10⁻² m·s⁻¹ for the speed of sound. The speed of sound was measured using a propagation time technique at the frequency 3 MHz. The densimeter was calibrated randomly with dry air at atmospheric pressure and doubly-distilled, freshly degassed and deionized water (ρ = 997.075 kg·m⁻³ at 298.15 K) supplied by Anton-Paar as described elsewhere. After each measurement, distilled water and anhydrous ethanol were used to clean the vibrating tube. The combined expanded uncertainties associated with the measurements for temperature, density and speed of sound are estimated to be within 0.01 K, 0.8 × 10⁻³ g·cm⁻³ and 0.5 m·s⁻¹, respectively, at the 95% confidence level.

The viscosities of the pure liquids and their mixtures were determined at atmospheric pressure at T = (303.15–318.15) K by using an Ubbelohde viscometer, which was calibrated with benzene, carbon tetrachloride, acetonitrile and doubly distilled water. The Ubbelohde viscometer bulb capacity was 15 mL and the capillary tube had a length of about 90 mm with 0.5 mm internal diameter. The viscometer was thoroughly cleaned and perfectly dried, filled with the sample liquid by fitting the viscometer to about 30° from the vertical, and its limbs were closed with Teflon caps to avoid evaporation. The viscometer was kept in a transparent walled bath with a thermal stability of ± 0.01 K for about 20 min to obtain thermal equilibrium before making the measurement. An electronic digital stopwatch with an uncertainty of ± 0.01 s was used for flow time measurements. The experimental uncertainty of viscosity of pure liquids was estimated at 0.17 mPa·s and the uncertainty of temperature ± 0.01 K. The combined expanded uncertainty of viscosity was estimated as 0.2 mPa·s. The purities of all these solvents were compared with the measured densities, speeds of sound and viscosities of the pure liquids with literature [9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28] and these comparisons are listed in Table 2 and graphically compared with the average absolute deviation (AAD) with literature values in Supplementary Material as Fig. 1S–9S. Density, speed of sound and viscosity values of 2-methylaniline were taken from our previous papers [29, 30].

Table 2 Densities, viscosities and speeds of sounds data of pure components at different temperatures and 0.1 MPa pressure

3 Results and Discussion

The experimental densities and sound velocities for all the binary systems at various compositions were used to calculate the excess thermodynamic functions, using the following equations:

$$ V^{{\text{E}}} \left( {{\text{m}}^{{\text{3}}} \cdot {\text{mol}}^{{ - 1}} } \right) = [x_{1} M_{1} + x_{2} M_{2} ]/\rho - [x_{1} M_{1} /\rho _{1} + x_{2} M_{2} /\rho _{2} ] $$

(1)

Deviation in viscosity were be calculated by following equation,

$$ \Delta \eta \left({\text{mPa}} \cdot {\text{s}} \right) = \eta {-}(x_{ 1} \eta_{ 1} + x_{ 2} \eta_{ 2} ) $$

(2)

where ρ, η and V are the density, viscosity and molar volume of the binary mixture. Also x₁, M₁, ρ₁, η₁, V₁ and x₂, M₂, ρ₂, η₂, and V₂ are the mole fraction, molar mass, density, viscosity and molar volume of pure components 1 and 2, respectively.

The experimental data were used to compute the isentropic compressibility (κ _S ) by using the following relation:

$$ \kappa_{S} = \, \left( {u^{ 2} \rho } \right)^{ - 1} $$

(3)

The method used for calculating $\kappa_{S}^{\text{E}}$ (Benson–Kiyohara approach) was outlined previously [31]:

$$ \kappa_{S}^{\text{E}} = \kappa_{S} - \, \kappa_{S}^{\text{id}} $$

(4)

where $\kappa_{S}$ is the isentropic compression and $\kappa_{S}^{\text{id}}$ is the isentropic compression of the ideal mixture,

$$ \kappa_{S}^{{\text{id}}} = \sum\limits_{{\text{i} = \text{1}}}^{\text{2}} {\phi_{i} \left[ {\kappa_{{S\text{.}{\text{i}}}} + TV_{i} \left( {\alpha_{i}^{\text{2}} } \right) / C_{p.i} } \right] - \left\{ {T\left( {\sum\limits_{{i = \text{1}}}^{\text{2}} {x_{i} V_{i} } } \right)\left( {\sum\limits_{{i = \text{1}}}^{\text{2}} {\phi_{i} \alpha_{i} } } \right)^{\text{2}} / \sum\limits_{{i = \text{1}}}^{\text{2}} {x_{i} C_{p.i} } } \right\}} $$

(5)

where ϕ _i is the volume fraction of component i, and $\kappa_{S}$, $V_{\text{m}}$, $\alpha_{p}$ and $C_{p}$ are the isentropic compressibility, molar volume, coefficient of isobaric thermal expansion and molar heat capacity, respectively, and R is the gas constant and T is the absolute temperature. The values of ϕ _i , $V_{\text{m}}^{\text{id}}$, $\alpha_{p}^{\text{id}}$ and $C_{p}^{\text{id}}$ were calculated using the following relations:

$$ \phi_{i} = \frac{{x_{i} V_{{{\text{m}},i}} }}{{\sum_{i = 1}^{2} x_{i} V_{{{\text{m}},i}} }} $$

$$ V_{\text{m}}^{\text{id}} = x_{1} V_{{{\text{m}},1}} + x_{2} V_{{{\text{m}},2}} $$

and

$$ C_{p}^{\text{id}} = x_{1} C_{p,1} + x_{2} C_{p,2} $$

Values of C _p were obtained from the literature [32]. α _p was calculated from measured densities by the relation,

$$ \alpha_{p} = \frac{1}{{V_{\text{m}} }}\left( {\frac{{\partial V_{\text{m}} }}{\partial T}} \right)_{p} = - \frac{1}{\rho }\left( {\frac{\partial \rho }{\partial T}} \right)_{p} = - \left( {\frac{\partial \ln \rho }{\partial T}} \right)_{p} $$

(6)

The V^E, $\kappa_{S}^{\text{E}}$ and ∆η values were fitted with a Redlich–Kister [33] polynomial equation,

$$ Y^{\text{E}} = x_{1} x_{2} \sum\limits_{i = 0}^{j} {A_{i} \left( {1 - 2x_{1} } \right)^{i} } $$

(7)

where Y^E represents V^E, $\kappa_{S}^{\text{E}}$ and ∆η. Values of the coefficients A _i have been determined by using the method of least squares. The standard deviations σ(Y^E) have been calculated by using the formula

$$ \sigma (Y^{\text{E}} ) = \left[ {\sum\limits_{m} {\left( {Y_{exp}^{\text{E}} - Y_{\text{calc}}^{\text{E}} } \right)/(m - n)^{1/2} } } \right] $$

(8)

where m is the total number of experimental points and n is the number of parameters. The coefficients, A _i and corresponding standard deviation values (σ) are presented in Table 6.

The observed V^E values can be discussed in terms of several effects, which are (i) physical, (ii) chemical and (iii) geometrical contributions [34]. (i) The physical interactions involve expansion due to mutual breaking of OH···O and N–H···N bonds present in the self-associated substituted ethanol and the amine; (ii) the chemical or specific interactions involves contraction due to complex formation between unlike molecules, which include hydrogen bond (HNH···OH and OH···N); and (iii) structural contributions resulting from geometrical fitting of one component into other, due to the difference in the free volumes between components, resulting in negative contributions to V^E.

The excess volume data reported in Tables 3, 4, and 5 at T = 303.15 K are graphically represented in Fig. 1 and in Fig. 10S at 313.15 K. The excess volume has negative values for all the studied systems over the whole composition range and at all experimental temperatures. The negative value of V^E may be due to the predominance of chemical or specific interactions and structural contributions dominating over physical contributions. Hence, the OH···N bond is stronger than the OH···O and N–H···N bonds in the mixtures [35]. The existence of strong O–H···N bond was also confirmed through NMR, IR and UV studies [36]. The same trend is observed for the system water + 2-aminoethanol [37].

Table 3 Density ($\rho$), excess molar volumes (V^E), speed of sound (u), excess isentropic compressibility ($\kappa_{S}^{\text{E}}$), viscosity (η) and deviation in viscosity (Δη) of binary liquid mixtures of 2-methylaniline with 2-phenylethanol at T = (303.15–318.15) K and 0.1 MPa pressure

Table 4 Density ($\rho$), excess molar volumes (V^E), speed of sound (u), excess isentropic compressibility ($\kappa_{S}^{\text{E}}$), viscosity (η), and deviation in viscosity (Δη) of binary liquid mixtures of 2-methylaniline with 2-chloroethanol at T = (303.15–318.15) K and 0.1 MPa pressure

Table 5 Density ($\rho$), excess molar volumes (V^E), speed of sound (u), excess isentropic compressibility ($\kappa_{S}^{\text{E}}$), viscosity (η) and deviation in viscosity (Δη) of binary liquid mixtures of 2-methylaniline with 2-aminoethanol at T = (303.15–318.15) K and 0.1 MPa pressure

Fig. 1

Variation of excess molar volume (V^E) with mole fraction (x₁) of 2-methylaniline for the binary liquid mixtures of 2-methylaniline with 2-aminoethanol (filled triangle), 2-chloroethanol (filled circle), and 2-phenylethanol (filled square) at 303.15 K

The values of V^E for the binary mixtures of 2-methylaniline with the substituted ethanols are in the following order:

$$ 2{\text{-aminoethanol }} < {2} {\text{-chloroethanol }} < {2}{\text{-phenylethanol}} $$

The more negative excess volume in the system 2-methylaniline + 2-aminoethanol reveals that more efficient packing and/or attractive interactions occur between these two components when mixed together. Consequently, its structure and smaller size lead to easier interstitial accommodation with 2-methylanilinemolecules compared to 2-methylaniline with 2-chloroethanol or with 2-phenylethanol. Similar results have been reported earlier [38, 39]. Hence the above order is justified.

Further, inspection of Tables 3, 4, 5 and Fig. 1 indicates that as the temperature increases from 303.15 to 318.15 K, the values of V^E for all these binary systems decrease. An increase in temperature increases the kinetic energy and therefore the breaking up of associate species present in the pure liquids, releasing more free dipoles of unlike molecules into the mixture, which results in interactions with each other and the formation of greater numbers of H-bonds between 2-methylaniline and the substituted ethanol’s monomer. This has already been described in the literature for 1-alkanol + hexane systems [40], alcohol + triethylene glycol systems [41] and 1-hexanol + ether systems [42].

Excess isentropic compressibility ($\kappa_{S}^{\text{E}}$) data for the mixtures of 2-methylaniline with substituted ethanols are graphically depicted in Fig. 2 at 303.15 K and Fig. 11S at 313.15 K and the data are given in Tables 3, 4, 5, and they show that the $\kappa_{S}^{\text{E}}$ values are negative over the entire mole fraction range at T = (303.15–318.15) K and become more negative with increasing temperature for all three binary mixtures. Thus, the mixtures are less compressible than the pure components, i.e., a greater resistance to compression (enhanced rigidity) is observed. The three systems show both enhanced rigidity ($\kappa_{S}^{\text{E}}$ < 0) and contraction (V^E < 0) over the entire composition range. In other words, the volume decreases (more compact packing of molecules), and simultaneously the whole system becomes more rigid (less compressible) [43]. As shown in Fig. 2, in the mixtures of 2-methylaniline and 2-phenylethanol, the trend of $\kappa_{S}^{\text{E}}$ is identical to that of the excess molar volumes. The same trend can be observed for other two systems. Interpretation of the $\kappa_{S}^{\text{E}}$ data is generally not simple because the $\kappa_{S}^{\text{E}}$ < 0 values are affected by both the molecular packing and the patterns of molecular aggregation induced by the molecular interactions. However, in these three binary systems it seems that the interpretation of negative $\kappa_{S}^{\text{E}}$ values will be the same as for the negative V^E values.

Fig. 2

Excess isentropic compressibility ($\kappa_{S}^{\text{E}}$) with mole fraction (x₁) of 2-methoxyanilinein the binary liquid mixtures of 2-methylaniline with 2-aminoethanol (filled triangle), 2-chloroethanol (filled circle), and 2-phenylethanol (filled square) at 303.15 K

The values of $\kappa_{S}^{\text{E}}$ for the binary mixtures of 2-methylaniline with substituted ethanols are in the following order:

$$ 2{\text{-aminoethanol }} < { 2}{\text{-chloroethanol }} < { 2}{\text{-phenylethanol}} $$

An examination of the curves in Fig. 3 at 303.15 K and Fig. 12S at 313.15 K indicates that the negative values for binary mixture containing 2-methylaniline and 2-phenylethanol are smaller than those of the other binary systems, because the phenyl group (–C₆H₅) has steric hindrence with the –NH₂ group. 2-Methylaniline has a free NH₂ group and easily interacts with the neighboring molecules [44,45,46]. Hence the above order is justified. The negative values of $\kappa_{S}^{\text{E}}$ increase with increasing temperature, which suggests that specific interactions increase due to the enhanced thermal energy. Comelli et al. [47] have also reported similar behavior for $\kappa_{S}^{\text{E}}$.

Fig. 3

Variation of the deviation in viscosity (Δη) from a linear mixing rule with mole fraction (x₁) of 2-methoxyaniline in the binary liquid mixtures of 2-methoxyaniline with 2-aminoethanol (filled triangle), 2-chloroethanol (filled circle), and 2-phenylethanol (filled square) at 303.15 K

A correlation between the signs of Δη and V^E has been observed for a number of binary solvent systems [48, 49], i.e., Δη is positive when V^E is negative and vice versa. In general, for systems where dispersion and dipolar interactions are operating, the Δη values are found to be negative, whereas donor–acceptor and hydrogen-bonding interactions lead to the formation of complex species between unlike molecules and thereby result in positive Δη values [50]. The viscosity deviation data of the liquid mixtures are graphically given in Fig. 3 and viscosity deviation data are given in Tables 3, 4, 5. The positive values of viscosity deviation for the binary systems investigated suggest that the hetero-molecular complexes between unlike molecules are relatively more numerous than those present in the pure components [51]. The effect of temperature increase is to disrupt hetero and homo association of the molecules resulting in an increase in fluidity of the liquids, giving higher Δη values at higher temperatures. The viscosity deviation values are found to be opposite to the sign of excess molar volumes for all binary mixtures, which is in agreement with the view proposed by Brocos et al. [52, 53].

As Tables 3, 4 and 5 show, the excess properties obtained are negative over the entire composition range and absolute values of V^E, $\kappa_{S}^{\text{E}}$, and $\Delta \eta$ increase (become more negative) with increasing temperature from T = (303.15–318.15) K. This effect can be attributed to the fact that the attractive interactions between like molecules become weaker with increasing temperature. Also, increasing temperature expands the volume of the mixture so that more space occurs between larger molecules that will become available for the smaller molecules to fill upon mixing. This packing effect will decrease the mixture volume.

4 Partial Molar Properties

The interpretations of excess partial molar properties ($\overline{V}_{\text{m,1}}^{\text{E}}$, $\overline{V}_{\text{m,2}}^{\text{E}}$, $\overline{K}_{\text{s,m,1}}^{\text{E}}$ and $\overline{K}_{\text{s,m,2}}^{\text{E}}$) and excess partial molar properties at infinite dilution ($\overline{V}_{\text{m,1}}^{{^\circ {\text{E}}}}$, $\overline{V}_{\text{m,2}}^{{^\circ {\text{E}}}}$ $\overline{K}_{\text{s,m,1}}^{{^\circ {\text{E}}}}$ and $\overline{K}_{\text{s,m,2}}^{{^\circ {\text{E}}}}$) of components 2 have previously been described [54].

In general, negative values of excess partial molar volume of component 1 and excess partial molar volumes of component 2 ($\mathop {\bar{V}_{{_{\text{m,1}} }}^{\text{E}} }\limits^{{}}$,$\bar{V}_{\text{m,2}}^{\text{E}}$, $\overline{K}_{\text{s,m,1}}^{\text{E}}$ and $\overline{K}_{\text{s,m,2}}^{\text{E}}$) indicate the presence of significant solute–solvent interactions between unlike molecules, whereas a positive excess partial molar volume of component 1 and excess partial molar volume component 2 data indicate the presence of solute–solute/solvent–solvent interactions between like molecules in the mixtures [55, 56].

A close perusal of Supplementary Table 1S and Fig. 4 indicates that the values of $\overline{V}_{\text{m,1}}^{\text{E}}$ and $\overline{V}_{\text{m,2}}^{\text{E}}$ are negative for all the binary mixtures over the whole composition range. Negative values may be attributed to hydrogen bonded complex formation between the components of the mixtures (Table 6).

Fig. 4

Variation of excess partial molar volumes, $\overline{V}_{\text{m,1}}^{\text{E}}$ and $\overline{V}_{\text{m,2}}^{\text{E}}$, of 2-methoxyaniline with 2-aminoethanol (filled triangle), 2-chloroethanol (filled circle), and 2-phenylethanol (filled square) at 303.15 K

Table 6 Coefficients of Redlich–Kister equation and standard deviation (σ) values for liquid mixtures of 2-methylaniline binary mixtures with substituted ethanols at T = (303.15–18.15) K

From the Supplementary Table 2S and Fig. 5 it may be inferred that the values of $\overline{K}_{\text{s,m,1}}^{\text{E}}$ and $\overline{K}_{\text{s,m,2}}^{\text{E}}$ are negative for all the binary mixtures over the whole composition range. The negative values indicate donor–acceptor interactions between the components of the mixtures.

Fig. 5

Variation of excess partial molar isentropic compressibilities, $\overline{K}_{\text{s,m,1}}^{\text{E}}$ and $\overline{K}_{\text{s,m,2}}^{\text{E}}$, of 2-methoxyaniline with 2-aminoethanol (filled triangle), 2-chloroethanol (filled circle), and 2-phenylethanol (filled square) at 303.15 K

From Table 7, it can be seen that the values of $\overline{V}_{\text{m,1}}^{{^\circ {\text{E}}}}$ and $\overline{V}_{\text{m,2}}^{{^\circ {\text{E}}}}$ are negative for all the binary mixtures over the whole composition range. The negative $\overline{V}_{\text{m,1}}^{{^\circ {\text{E}}}}$ and $\overline{V}_{\text{m,2}}^{{^\circ {\text{E}}}}$ values indicate strong specific interactions through a hetero association complex formation between 2-methylaniline and a substituted ethanol molecule.

Table 7 The values of $V_{\text{m,1}}^{^\circ }$, $V_{\text{m,1}}^{ *}$, $V_{\text{m,1}}^{{^\circ {\text{E}}}}$, $V_{\text{m,2}}^{^\circ }$, $V_{\text{m,2}}^{ *}$ and $V_{\text{m,2}}^{{^\circ {\text{E}}}}$ of the components for 2-methylaniline binary mixtures with substituted ethanols at T = (303.15–18.15) K

It is seen from Table 8 that the values of $\overline{K}_{\text{s,m,1}}^{{^\circ {\text{E}}}}$ and $\overline{K}_{\text{s,m,2}}^{{^\circ {\text{E}}}}$ are negative for all the binary systems at each investigated temperature. The negative values may be due to the strong chemical and specific interactions through charge transfer complex formation between the components of the binary mixtures.

Table 8 The values of $\overline{K}_{\text{s,m,1}}^{^\circ }$, $K_{\text{s,m,1}}^{ *}$, $\overline{K}_{\text{s,m,1}}^{{^\circ {\text{E}}}}$, $\overline{K}_{\text{s,m,2}}^{^\circ }$, $K_{\text{s,m,2}}^{ *}$ and $\overline{K}_{\text{s,m,2}}^{{^\circ {\text{E}}}}$ of the components for 2-methylaniline binary mixtures with substituted ethanols at T = (303.15–18.15) K

5 Conclusion

This paper reports experimental data of densities, speeds of sound and viscosities of binary blends of 2-methylaniline with substituted ethanol (2-phenylethanol, 2-chloroethanol and 2-aminoethanol) binary mixtures over the entire composition range at T = (303.15–318.15) K with 5 K interval. From the experimental data, various physicochemical parameters, viz., $V_{\text{m}}^{\text{E}}$, $\kappa_{S}^{\text{E}}$ and Δη of the mixtures, the excess partial molar properties ($\overline{V}_{\text{m,1}}^{\text{E}}$, $\overline{V}_{\text{m,2}}^{\text{E}}$, $\overline{K}_{\text{s,m,1}}^{\text{E}}$ and $\overline{K}_{\text{s,m,2}}^{\text{E}}$) and excess partial molar properties at infinite dilution ($\overline{V}_{\text{m,1}}^{{^\circ {\text{E}}}}$, $\overline{V}_{\text{m,2}}^{{^\circ {\text{E}}}}$ $\overline{K}_{\text{s,m,1}}^{{^\circ {\text{E}}}}$ and $\overline{K}_{\text{s,m,2}}^{{^\circ {\text{E}}}}$) of the components have been calculated.