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Nagarjun B.,P.A. College | Sarma A.V.,Andhra University | Rao G.V.R.,DAR College | Rambabu C.,Acharya Nagarjuna University
Journal of Thermodynamics | Year: 2013

Speeds of sound and density for binary mixtures of ethyl benzoate (EB) with N,N-dimethylformamide (NNDMF), N,N-dimethyl acetamide (NNDMAc), and N,N-dimethylaniline (NNDMA) were measured as a function of mole fraction at temperatures 303.15, 308.15 K, 313.15 K, and 318.15 K and atmospheric pressure. From the experimental data, adiabatic compressibility (β ad), intermolecular free length (L f), and molar volume (V) have been computed. The excess values of the above parameters were also evaluated and discussed in light of molecular interactions. Deviation in adiabatic compressibilities and excess intermolecular free length (L f E) are found to be negative over the molefraction of ethyl benzoate indicating the presence of strong interactions between the molecules. The negative excess molar volume V E values are attributed to strong dipole-dipole interactions between unlike molecules in the mixtures. The binary data of Δβ ad, V E, and L f E were correlated as a function of molefraction by using the Redlich-Kister equation. © 2013 B. Nagarjun et al. Source


Kumar D.B.K.,Acharya Nagarjuna University | Reddy K.R.,Acharya Nagarjuna University | Rao G.S.,Andhra Loyala College | Sandhyasri P.B.,DAR College | And 2 more authors.
Journal of Molecular Liquids | Year: 2013

The ultrasonic speed (U) studies are carried out using single crystal variable path fixed frequency (2 MHz) ultrasonic interferometer on some aliphatic esters in N-methyl-2-pyrrolidone (NMP) at temperatures of 303.15, 308.15, 313.15 and 318.15 K. Excess molar volume, excess isobaric thermal expansion coefficient, excess isentropic compressibility and excess ultrasonic speed are computed from the experimentally measured ultrasonic speeds and densities of pure liquids NMP, methyl acetate (MA), ethyl acetate (EA), butyl acetate (BA) and their binary mixtures over the entire range of composition of NMP. The variation of these properties with composition and temperature of the binary mixtures is discussed in terms of molecular interactions of component molecules. The excess parameters are fitted to a Redlich-Kister type polynomial and the corresponding standard deviations are calculated. Thermodynamic parameters under study suggest the existence of strong interactions between NMP and aliphatic esters. The experimental data of viscosity is used to test the applicability of empirical relations of Grunberg-Nissan, Katti-Chaudhri, Heric-Brewer and McAllister for the systems studied. Also, ultrasonic speeds are theoretically evaluated based on scaled particle theory and compared with the experimentally measured values. The study reveals a close agreement between experimental and theoretical values of ultrasonic speed of these mixtures at all the temperatures under study. An attempt is made to study the temperature effect on the shapes of the interacting molecules in the binary liquid mixture using scaled particle theory in the temperature range 303.15-318.15 K. © 2013 Elsevier B.V. Source


Bala Karuna Kumar D.,Acharya Nagarjuna University | Rayapa Reddy K.,Acharya Nagarjuna University | Rama Rao G.V.,DAR College | Rambabu C.,Acharya Nagarjuna University
Asian Journal of Chemistry | Year: 2012

Theoretical velocities of binary liquid mixtures of N-methyl-2-pyrrolidone (NMP) with aniline (AB), bromobenzene (BB) and chlorobenzene (CB) at temperature = (303.15, 308.15, 313.15, 318.15) K and atmospheric pressure have been evaluated by using theoretical models such as Nomoto, Van Dael-Vangeel ideal mixing, impedance dependence, Rao's specific velocity method and Junjie's relations. Ultrasonic velocities and densities of these mixtures have also been measured experimentally as a function of composition of N-methyl-2-pyrrolidone and temperature. A good agreement is found between experimental and theoretical values. U 2 exp/U 2 imx has also been evaluated for nonideality in the mixtures. Chi-square test for the goodness of the fit is applied to investigate the relative applicability of these theories to the present systems. The results are discussed in terms of intermolecular interactions between the component molecules in these binary liquid mixtures. Source


Reddy K.R.,Acharya Nagarjuna University | Kumar D.B.K.,Acharya Nagarjuna University | Rao G.S.,Andhra Loyala College | Sri P.B.S.,DAR College | Rambabu C.,Acharya Nagarjuna University
Fluid Phase Equilibria | Year: 2012

Consistent vapor-liquid equilibria (VLE) data at 95.3. kPa have been determined for the binary mixtures of N-methyl-2-pyrrolidone (NMP) +2-methoxyethanol (2-ME), +2-ethoxyethanol (2-EE), +2-butoxyethanol (2-BE) over the entire composition range using a Swietoslawski ebulliometer. The VLE data have been correlated by the Wilson model. The investigated binary systems show negative deviation from Raoult's law. None of the binary systems form maximum or minimum boiling point azeotropic mixtures. Also, densities of all three binary liquid mixtures over the entire mole fraction range are measured at 303.15, 308.15, 313.15, and 318.15. K using densimeter. Excess molar volumes are computed with variation in composition and temperature, and are correlated by the Redlich-Kister polynomial equation. The results of activity coefficients, excess Gibb's energies and excess molar volumes are correlated, and are discussed in terms of molecular interactions. Also, the effects of temperature and chain length of alkoxyethanols are studied and are discussed in terms of molecular interactions. © 2012 Elsevier B.V. Source


Karuna Kumar D.B.,Acharya Nagarjuna University | Reddy K.R.,Acharya Nagarjuna University | Rao G.S.,Andhra Loyala College | Rao G.V.R.,DAR College | Rambabu C.,Acharya Nagarjuna University
Journal of Molecular Liquids | Year: 2012

The densities and viscosities for pure liquids N-methyl-2-pyrrolidone (NMP), aniline (AB), bromobenzene (BB), chlorobenzene (CB) and their binary mixtures containing NMP as a common component have been measured at 303.15, 308.15, 313.15 and 318.15 K as a function of composition of NMP. From these results, excess molar volumes, excess Gibb's free energy of activation of viscous flow and deviations in viscosity are computed. Excess properties are fitted to a Redlich-Kister type equation and the corresponding standard deviations are calculated. The experimental data of viscosity is used to test the applicability of empirical relations of Grunberg-Nissan, Katti-Chaudhri, Heric-Brewer and Hind et al. for the systems studied. The excess molar volumes are found to be negative whereas the deviations in viscosity and excess Gibb's free energy of activation of viscous flow values are found to be positive for all the mixtures, over the entire composition range. Partial molar volumes and apparent molar volumes at infinite dilution have been calculated. The variation of these properties with composition of NMP and temperature is discussed in terms of molecular interactions between component molecules. The strength of interaction of AB, BB, CB with NMP is found to obey the order AB > CB > BB. The IR, spectral studies of these binary mixtures also suggest specific interaction between the unlike molecules of the components and supported thermodynamic findings. © 2012 Elsevier B.V. Source

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