Ramamurthy Palepu

Viscosities and densities of 2,2,2-trifluoroethanol + water at various temperatures

Abstract The densities and viscosities at 298, 303, 308 and 313 K for 2,2,2-trifluoroethanol + water were determined. From experimental results, the excess viscosity and excess molar free energy of activation of flow were computed and are presented as a function of the mole fraction of 2,2,2-trifluoroethanol. The deviation from additivity in the values of the excess parameters is discussed in terms of the strength of the interaction between the components of the mixture.

Effect of microheterogeneity on bulk and surface properties of binary mixtures of polyoxyethene glycol monobutyl ethers with water

Solution properties of aqueous mixtures of the homologous series of polyoxyethene glycol mono-n-butyl ethers C4H9O(CH2CH2O)m H (where m=1 to 3) have been investigated using surface tension, density, viscosity and13C NMR techniques. From the experimental data, excess volume and deviation of viscosity and free energy of activation of flow were evaluated and discussed in terms of the molecular interactions between the components. Surface activity of polyoxyethene glycol mono ethers in aqueous dilute solutions was evident from surface tension measurements. Thermodynamic properties of adsorption and apparent micellization or critical aggregation concentration (CAC) in these systems were evaluated and discussed. The CAC values and the aggregation numbers obtained from13C NMR chemical shift data indicate an increase in hydrophobicity with an increase in the value of m, in the polyoxyethene glycol mono-n-butyl ethers, and also agrees with the results obtained from surface tension measurements.

Viscosities and densities of binary liquid mixtures of 2-butoxyethanol with aniline and N-alkylaniline

Abstract Viscosities and densities of binary liquid mixtures containing 2-butoxyethanol as one component and aniline or N -alkylaniline as the other component have been measured over the whole composition range at five different temperatures. McAllisters approach correlates the viscosity data with a significantly high degree of accuracy for all these systems. From the experimental results, the excess volume, excess viscosity and excess molar free energy of activation of flow have been evaluated and the departure from ideal behaviour is explained on the basis of specific interactions between the components in these mixtures.

Thermodynamic and transport properties of binary liquid acid—base mixtures. Part 1

Abstract Densities and viscosities were determined at five different temperatures for the systems quinoline (Q) with: phenol (P); ortho-chlorophenol (CP); and meta-cresol (MC). From the experimental results the excess volumes, excess viscosities, partial molar excess volumes and the partial molar volumes were calculated. From the dependency of viscosity on temperature, the thermodynamic parameters of activation of flow were also calculated and these results were discussed in terms of the type of interaction between the two components in solution.

Counterion binding by surfactant/β-cyclodextrin inclusion complexes

Sodium ion activities were determined potentiometrically in sodium dodecylsulfate and sodium dodecanoate solutions containingβ-cyclodextrin. Whereas sodium ion did not bind withβ-cyclodextrin, its activity decreased noticeably when the 1:1β-cyclodextrin/surfactant inclusion complex was formed in solution. When the anionic guest was methyl red or methyl orange, no sodium ion binding occurred. When the guest was the cationic dodecylammonium ion in chloride solutions containingβ-cyclodextrin, pronounced chloride ion binding to the 1:1 inclusion complex occurred.

Viscosity and densities of binary mixtures of acetonitrile with substituted anilines. Part 4

Abstract Viscosity and density data are presented for five binary liquid mixtures of acetonitrile with aniline and substituted anilines at five different temperatures. The experimental data are fitted to semitheoretical equations proposed by McAllister and Heric. Excess viscosity, excess volume and the excess Gibbs energy of activation of flow have been calculated from the experimental data. Various thermodynamic parameters of activation of flow are calculated from the dependence of viscosity on temperature. The deviations from ideality of thermodynamic and transport functions are explained on the basis of molecular interactions between the components of the mixture.

Dielectric and Index of Refraction Properties of Binary Mixtures of Polyoxyethene Glycol Monobutyl Ethers with Water

Dielectric constants and indices of refraction of aqueous mixtures of the homologous series of polyoxyethene glycol mono-n-butyl ethers C 4 H 9 O(CH 2 CH 2 O) m H (where m = 1 to 3) were measured. From the experimental data, excess dielectric permittivities, dielectric molar susceptibilities, molar and molar orientational polarizabilities were evaluated. Also excess Lorentz-Lorentz molar refractions were evaluated and the results were discussed in terms of departure from ideality and intermolecular interactions in the mixtures

Physicochemical properties of concentrated solutions of some alkali metal halides in aqueous thiourea solutions

Abstract Viscosity, density and ultrasonic velocity measurements of some alkali metal halides in 1 M thiourea solution at four different temperatures have been determined. The viscosity data are analysed in terms of various viscosity equations to obtain B coefficients. Ionic viscosity coefficients, hydration numbers, apparent partial molar volumes and free volumes are calculated and discussed in terms of solute-solvent interactions. Activation parameters of viscous flow are calculated and discussed in terms of structure-breaking or making properties of the electrolyte solutions.

Solid—liquid phase diagrams and X-ray diffraction studies on mixtures. I.

Present emphasis on energy research has led to increased interest in the nature of coal-derived asphaltenes which are constituents of coal liquefaction products’. Asphaltenes essentially possess an acid-base structure’ and recent spectroscopic3 and calorimetric4 studies involving model compounds have shown that the separate acid and base components can interact with each other through the formation of hydrogen bonded complexes. As part of a program dealing with solid-liquid equilibria studies involving model compounds of asphaltenes, we report here the preliminary investigations dealing with the phase diagrams of simple phenols (acid) with wide variety of basic compounds.

Thermodynamics and free volume of various alkali halides in aqueous d-mannitol solution

Abstract Ultrasonic, density and viscometric investigations have been conducted on several alkali halides in 0.4 M aqueous d -mannitol solution at four different temperatures: 25, 30, 35 and 40°C. Free volumes, internal pressures, ionic viscosity coefficients, and hydration numbers have been calculated. Activation parameters of viscous flow were also calculated and all these properties were discussed in terms of structure-making or -breaking properties of electrolytes in aqueous d -mannitol solutions. Results show that in addition to viscometric properties, the temperature dependency of free volumes and internal pressures is found to be a powerful tool in elucidating the structure-making or -breaking properties of the electrolyte solutions.