Entity

Time filter

Source Type

Telangana, India

Nayeem S.M.,KRK Government Degree College | Kondaiah M.,NM Government Degree College | Sreekanth K.,PBN College | Srinivasa Reddy M.,KRK Government Degree College | Krishna Rao D.,Acharya Nagarjuna University
Journal of Thermal Analysis and Calorimetry | Year: 2016

Ultrasonic velocity, u, density, ρ, and viscosity, η, have been measured in the binary liquid mixture of 1,4-dioxane with n-hexane or n-heptane or n-octane at 308.15, 313.15, and 318.15 K over the entire composition range. Properties such as molar volume, V m, intermolecular free length, L f, acoustic impedance, Z, internal pressure, π i, enthalpy, ΔH, Gibb's free energy of activation of viscous flow, Δ G ∗, and their excess/deviation properties such as deviations in ultrasonic speed, Δu, viscosity, Δ η, excess molar volume, V m E, excess intermolecular free length, L f E, excess acoustic impedance, Z E, excess internal pressure, π i E, excess enthalpy, Δ H E, and excess Gibb's free energy of activation of viscous flow, Δ G ∗ E, have been calculated from the experimental data. The calculated deviation/excess properties have been fitted to the Redlich-Kister-type polynomial equation. Partial molar volumes, (V ¯ m,1, V ¯ m,2), and excess partial molar volumes, (V ¯ m,1 E, V ¯ m,2 E), have also been evaluated. The observed positive and negative values of the relevant deviation/excess properties are attributed to the dominance of weak interactions (physical interactions) between the unlike molecules in the mixtures, and the strength of weak interactions follows the order: (1,4-dioxane + n-octane) > (1,4-dioxane + n-heptane) > (1,4-dioxane + n-hexane). The prevailing physical interactions are found to increase with the increase in temperature. The experimental data of ultrasonic velocity and viscosity have been used to check the applicability of various velocity and viscosity theory models at all temperatures under investigation. © 2015 Akadémiai Kiadó, Budapest, Hungary.


Kondaiah M.,NM Government Degree College | Sreekanth K.,PBN College | Sravana Kumar D.,SVLNS Government Degree College | Krishna Rao D.,Acharya Nagarjuna University
Journal of Thermodynamics | Year: 2014

Densities, ρ, and ultrasonic speeds, u of mixtures of 1-butanol or iso-butanol or t-butanol with equimolar mixture of (N,N-dimethylacetamide + Ethyl acrylate) over the entire composition range have been measured at T=308.15 K. Using the experimental results, deviation in ultrasonic speed, Δu, deviation in isentropic compressibility, Δks, excess molar volume, VmE, excess intermolecular free length, LfE, and excess acoustic impedance, ZE, have been calculated. The variation of these properties with composition of the mixtures has been discussed in terms of molecular interactions in these mixtures. The deviation/excess properties have been fitted to Redlich-Kister type polynomial and the corresponding standard deviations have been calculated. Negative values of VmE, Δks, and LfE and positive values of Δu, and ZE are observed over the entire composition range. The observed negative and positive values of deviation/excess properties are attributed to the strong interactions between the unlike molecules of the mixtures. Further theoretical values of sound velocity in the mixtures have been evaluated using various theories and compared with experimental sound velocities to verify the applicability of such theories to the systems studied. Theoretical ultrasonic velocity data has been used to study molecular interactions in the systems investigated. © 2014 M. Kondaiah et al.


Md Nayeem S.,KRK Government Degree College | Kondaiah M.,NM Government Degree College | Sreekanth K.,PBN College | Krishna Rao D.,Acharya Nagarjuna University
Journal of Thermodynamics | Year: 2014

Ultrasonic velocities (u), densities (ρ), and viscosities (η) of binary liquid mixtures of cyclohexanone with benzyl benzoate, including pure liquids, over the entire composition range have been measured at 308.15 K, 313.15 K, and 318.15 K. Using the experimental results, parameters such as molar volume (V m), isentropic compressibility (k s), intermolecular free length (L f), acoustic impedance (Z), internal pressure (π i), enthalpy (H), Gibbs free energy of activation of viscous flow (G E), and excess/deviation properties of these including partial molar volumes (V - m, 1 and V - m, 2), excess partial molar volumes (V - m, 1 E and V - m, 2 E), partial molar volume of the components at infinite dilution (V - m, 1 ∞, V - m, 2 ∞), and excess partial molar volume at infinite dilution (V - m, 1 E, ∞ and V - m, 2 E, ∞) have been computed. The observed negative values of V m E, Δ k s, L f E, and π i E and positive values of z E, H E, Δ G E, Δ η, and Δ u for all the liquid mixtures studied clearly indicate the presence of strong dipole-dipole-type interactions, fitting of smaller molecules into bigger molecules. Further theoretical values of sound velocity and viscosity in the mixtures have been evaluated using various theories and have been compared with experimental values to verify the applicability of such theories to the systems studied. © 2014 Sk. Md Nayeem et al.


Nayeem S.M.,P.A. College | Kondaiah M.,NM Government Degree College | Sreekanth K.,P.A. College | Rao D.K.,Acharya Nagarjuna University
Journal of Molecular Liquids | Year: 2015

Ultrasonic velocities, u, densities, ρ, of binary liquid mixtures of 1-octanol with acetophenone (AP), cyclopentanone (CP), and 3-Pentanone (3P), including pure liquids, over the entire composition range have been measured at 308.15 K. Using the experimental results, parameters such as molar volume (Vm), isentropic compressibility (ks), acoustic impedance (z) and their excess/deviation properties have been calculated. The calculated deviation/excess properties have been fitted to the Redlich-Kister type polynomial equation. Partial molar volumes, excess partial molar volumes and partial molar compressibilities, excess partial molar compressibilities have also been calculated. The observed positive values of VmE, δks, and negative values of zE for all the liquid mixtures indicate the domination of rupture of existing H-bond or reduction in H-bond strength between the carbonyl group (-CO) of ketones and the hydroxyl group (-OH) of 1-octanol. The strength of weak interactions follows the order: (1-octanol + 3P) > (1-octanol + CP) > (1-octanol + AP). Further, FTIR spectra also support the conclusions drawn from excess/deviation properties. Moreover, theoretical values of sound velocity in the mixtures have been evaluated using various theories and compared with experimental sound velocities to verify the applicability of such theories to the systems studied. © 2015 Elsevier B.V.


Nayeem S.,P.A. College | Kondaiah M.,NM Government Degree College | Sreekanth K.,P.A. College | Krishna Rao D.,Acharya Nagarjuna University
Arabian Journal of Chemistry | Year: 2015

Ultrasonic velocities, u, and densities, ρ, of binary liquid mixtures of dimethyl sulphoxide (DMSO) with ketones such as acetophenone (AP), cyclohexanone (CH), and 3-pentanone (3P), including pure liquids, over the entire composition range have been measured at 308.15. K. Using the experimental data, deviation in ultrasonic velocity, δ. u, deviation in isentropic compressibility, δ. ks , excess molar volume, VmE, excess intermolecular free length, LfE and excess acoustic impedance, ZE , partial molar volumes, V[U+203E]m,1, V[U+203E]m,2, and excess partial molar volumes, V[U+203E]m,1E, V[U+203E]m,2E have been calculated. Molecular interactions in the systems have been studied in the light of variation of excess/deviation values of calculated properties and these properties have been fitted to Redlich-Kister type polynomial equation. The observed positive values of VmE, δ. ks , LfE and negative values of δ. u, ZE for all the binary liquid mixtures studied clearly indicate the presence of the dominance of weak physical interactions between the components of molecules. Further, FTIR spectra support the conclusions drawn from deviation/excess properties. Moreover, theoretical values of ultrasonic velocity in the mixtures have been evaluated using various theories and such values were compared with experimental velocities to verify the applicability of such theories to the systems investigated. © 2015 The Authors.

Discover hidden collaborations