Search

The transport behavior of copper(I) nitrate electrolytes has been evaluated in the concentration range (4.0–100) × 10–4 mol·dm−3 in dimethylsulfoxide (DMSO), pyridine (Py) and nitromethane (NM) and their binary solvent mixtures containing 0, 0.20, 0.40, 0.60, 0.80, and 1.00 mol fraction of Py and NM at 298 K by conductance measurements. Parameters like limiting molar conductance (Ʌ0), association distance (R), Stokes radii (ri), and Walden product have been calculated using the molar conductance data. It is evident from the Stokes radii values that the ion solvation increases in the order Py > DMSO > NM indicating stronger solvation in the case of Py than for DMSO and than for NM. The above trend was further supported by Walden product values indicating more extensive solvation in Py. [ABSTRACT FROM AUTHOR]

The dielectric complex spectra of 2-nitrotoluene with primary or secondary alcohol binary mixtures were studied over the frequency range of 10 MHz to 20 GHz for the whole solute mole fraction range at four different temperatures. An unusual suppression phenomenon was observed in the real and imaginary parts of the mixture complex spectrum, which are smaller than those for the pure alcohols, at low solute concentrations. The dielectric constant and dielectric relaxation time values were obtained by fitting the complex dielectric spectrum data to the single Debye model using a non-linear least squares method. The dielectric constant of mixtures decrease with the increasing mole fraction of 2NT in both the primary alcohols and secondary alcohols; the dielectric relaxation time decreases for all the five binary systems. Using the dielectric data, derived dielectric parameters, namely: the excess dielectric constant, excess inverse relaxation time, effective Kirkwood correlation factor, molar activation enthalpy and molar activation entropy, were calculated. The non-linear variation of permittivity (ɛ0) reveals the change in size and shape of hetero-molecular complex due to intermolecular H-bond interaction. The negative variation of the excess permittivity constant confirms that the dipoles form multimer structures with anti-parallel ordering of unlike dipoles. The molar activation enthalpy was found to be higher at 0.2 mol fraction of 2NT for primary alcohol binary system. To confirm the molecular function group interaction, a FT-IR spectroscopy study was carried out at 298 K. The FT-IR analysis confirmed the formation of hydrogen bonds between the hydrogen atom of hydroxyl groups of the alcohols and the oxygen atom of nitro groups of 2NT in the binary mixtures. [ABSTRACT FROM AUTHOR]

The complex dielectric spectra of nitrobenzene, 2-butanol and their binary mixtures were measured in the frequency range of 10 MHz-20 GHz at different temperatures using Time Domain Reflectometry. The static permittivities and relaxation times were extracted from the complex dielectric spectra of the pure compounds and binary mixtures by fitting to the Debye model using the least-squares fitting method. The derived static permittivity ( ε) and dielectric relaxation time ( τ) values were used to calculate various dielectric parameters including the excess dielectric constant, effective Kirkwood correlation factor, excess inverse relaxation time and thermodynamic parameters. Excess dielectric parameters were fitted with the Redlich-Kister type polynomial equation. The result from dielectric analyses confirms the formation of a heterogeneous complex structure by association of unlike molecules. This hetero-molecule interactions produce a electric field in the mixtures and, as a result, the effective dipoles rotate faster. Molecular rotation and dipole reorientation motions in these complex system are discussed in terms of the molar activation entropy and enthalpy. Additionally, the hydrogen bond interaction between solute and solvent were confirmed by FT-IR spectral analysis. [ABSTRACT FROM AUTHOR]

Apparent molar volumes ( V) and apparent molar isentropic compressions ( K) for saccharides d(+)-glucose and d(−)-fructose have been determined in water and (0.2, 0.4, and 0.6) mol·kg aqueous solutions of trisodium citrate at T = (288.15, 298.15, 308.15 and 318.15) K and atmospheric pressure from density and speed of sound data. The partial molar volumes ( $$ V_{\phi }^{0} $$ ) and the standard partial molar volumes of transfer ( $$ \Delta V_{\phi }^{0} $$ ) from water to aqueous trisodium citrate solutions have been calculated. The partial molar expansion coefficients $$ (\partial V_{\phi }^{0} /\partial T)_{p} $$ and their second derivative $$ (\partial^{2} V_{\phi }^{0} /\partial T^{2} )_{p} $$ have also been estimated. The partial molar isentropic compression ( $$ K_{\phi ,S}^{0} $$ ) and partial molar isentropic compression of transfer ( $$ \Delta K_{\phi ,S}^{0} $$ ) have been calculated from the speed of sound data. Pair and triplet interaction parameters ( V, V) and ( K and K) from volumetric and speed of sound data, respectively, have been calculated using the McMillan-Mayer theory The results are discussed in terms of stereochemistry of the solutes and prevailing interaction in the mixtures. [ABSTRACT FROM AUTHOR]

Density ( ρ), speed of sound ( u) and viscosity ( η) have been measured for the binary mixtures of N-ethylaniline with 1-hexanol, 1-heptanol, 1-octanol, and 1-decanol over the entire composition range at 303.15, 308.15, and 313.15 K. By using this data, the excess volume ( V), excess isentropic compressibility $$ \left( {\kappa_{S}^{\text{E}} } \right) $$ , excess viscosity ( η) and excess Gibbs energy of activation of viscous flow ( G) have been calculated and fitted to the Redlich-Kister polynomial equation. The excess molar volumes, excess isentropic compressibility, excess viscosity and excess Gibbs energy of activation of viscous flow have been analyzed in terms of declustering and breaking of hydrogen bonds in alkanols in the presence of the solute, repulsive forces due to the electric charge of components, size and shape of both component molecules, along with effect of the alkyl chain of the 1-alkanols. The experimental viscosity data of all the binary mixtures were used to test the semi-empirical relations of Grunberg-Nissan, Katti-Chaudhri, and Hind. [ABSTRACT FROM AUTHOR]

In this paper density, sound velocity, and refractive index for the binary system (butyric acid + hexanoic acid) were measured over the entire composition range and at 5 K intervals in the temperature range 293.15-313.15 K. The excess molar volumes, isentropic compressibilities, excess isentropic compressibilities, deviation in refractive indices, molar refractions, and deviation in molar refractions were calculated by using the experimental densities, sound velocities, and refractive indices, respectively. The Redlich-Kister equation was used to fit the excess molar volume, excess isentropic compressibility, deviation in refractive index and deviation in molar refraction data. The Lorentz-Lorenz approximation was used to correlate the excess molar volume from the deviation in refractive index and also to predict the density from refractive index or the refractive index from density of the binary mixtures. Four sound velocity mixing rules were tested and the best model for the systems studied in this work was the Berryman mixing rule. The thermodynamic properties are discussed in terms of intermolecular interactions between the components of the mixtures. [ABSTRACT FROM AUTHOR]

Experimental densities ( ρ), viscosities ( η), and speeds of sound ( u) of the binary mixtures of n-dodecane with an alkan-1-ol (hexan-1-ol, heptan-1-ol, octan-1-ol) or an alkan-2-ol (hexan-2-ol, heptan-2-ol and octan-2-ol) were measured over the whole mixture composition range at T = 298.15 K. From these data, the excess molar volume ( $$ V_{\text{m}}^{\text{E}} $$ ), deviations in viscosity (Δ η), and excess isentropic compressibility ( $$ \kappa_{S}^{\text{E}} $$ ) have been calculated. The results were fitted by means of the Redlich-Kister equation, in order to estimate the binary coefficients and standard errors. Differences among these binary systems are ascribed to the different association abilities of the alkan-1-ols and alkan-2-ols. Experimental data on the constituted binaries were analyzed using McAllister's multi-body interaction model, the Jouyban-Acree model, the Prigogine-Flory-Patterson theory, and the Bloomfield and Dewan model. The experimental and calculated quantities are used to study the nature of mixing behavior among the mixtures. [ABSTRACT FROM AUTHOR]

Conductivities of symmetrical and unsymmetrical electrolytes of 2:2, 3:3, 1:2, 2:1 and 1:3 types in ethanol-water and the 1,4-dioxane-water mixtures were analyzed using the Quint-Viallard conductivity equation and taking into account the ion association effect. The molar limiting conductances and the ion association constants were reexamined for various multivalent electrolytes. One non-aqueous system, methanol-ethylene glycol mixtures, was also considered. The limiting conductances were also examined in the framework of universal curves of limiting conductances and the excess Walden products introduced by the author. These new concepts in the analysis of conductance data allow the estimation of values of limiting conductances of electrolytes or ions, to give an indication about the quality of the conductivity measurements and the type of interactions expected in the systems. It was found that for any type of electrolyte only one universal curve of limiting conductances exists. In the water-rich mixtures, attractive interactions (structure-making effects) are expected when electrolytes are added to mixtures with ethanol or with 1,4-dioxane. In contrast, in ethylene glycol-methanol-rich mixtures repulsive interactions (structure-breaking effects) are more likely. [ABSTRACT FROM AUTHOR]