S. K. Dash

Ultrasonic investigation in a polar-polar system—metyl isobutyl ketone (MIBK) and aliphatic alcohols

Abstract The ultrasonic velocity in binary mixtures of MIBK with eight aliphatic alcohols viz. 1-propanol, 1-butanol, 1-pentanol, 1-hexanol, 1-heptanol, 1-octanol and 1-decanol is measured at frequency 2MHz and temperature 303.16 K for entire range of concentration using an ultrasonic interferometer. The measured data are used to compute isentropic compressibility, molar compressibility, inter molecular free length, available volume and acoustic impedance. The excess properties are also evaluated. The trends of variation of these parameters indicate that the nature of interaction is dependent upon chain-length of alcohols. The findings are compared with the results obtained from dielectric studies undertaken earlier.

Dielectric investigation on a nuclear extractant-acetylacetone (HAA) in nonpolar solvents

Abstract The relative permittivity of binary mixtures of acetylacetone (HAA) a nuclear extractant with six nonpolar solvents is measured at frequency 455 kHz and temperature 303.16K. The dielectric constant data are used to compute the linear correlation factor, excess molar polarization and excess Gibbs free energy in the binary mixtures. The molecular interaction is found to be dependent upon concentration of HAA as well as the nature of the solvent.

Dielectric Studies on Binary Mixtures of Tri-n-butyl Phosphate (TBP) and Long-Chain Primary Alcohols (Modifiers)

Dielectric constant (e) of Tri-n-butyl phosphate (TBP), in binary mixtures with five long-chain primary alcohols viz; 1-butanol, 1-pentanol, 1-hexanol, 1-heptanol and 1-octanol has been measured at ν=455 kHz and at temperature 302 K. The data is used to evaluate mutual correlation factor gab, excess molar polarization ΔP and excess free energy of mixing ΔFab by using Winkelmann-Quitzsch eqn. for binary mixtures to assess the suitability of the alcohols as modifiers. The trend of variation of these parameters exhibit marked dependence on chain-length of the alcohols indicating 1-heptanol to be an efficient modifier.

Molecular Interaction in Binary Mixtures of Tri-N-Butyl Phosphate (TBP) and Aliphatic Alcohols-Effect of Free Volume and Internal Pressure

Abstract The ultrasonic velocity, density and viscosity in binary mixtures of TBP with a number of aliphatic primary alcohols viz. methanol, ethanol, 1-hexanol, 1-heptanol, 1-octanol and 1-decanol have been measured at frequency 3 MHz and at temperature 303.16 K. The data are used to compute excess internal pressure and excess enthalpy in these mixtures. The results corroborate the findings of these authors from dielectric studies that the interaction is maximum in 1 heptanol-TBP system and microheterogeneous β-clusters with antiparaliel orientation of dissimilar molecules predominate in it.

Dipolar Interaction in Binary Polar Systems-a Dielectric Study of Acetyl Acetone (HAA) and DI-ISO Butyl Ketone (DIBK) with Some Monosubstituted Benzenes

Abstract Experimentally measured values of dielectric constant (∊) at a frequency of 455 kHz and temperature 303.16K in binary polar mixture of acetyl acetone and of di-iso-butyl ketone in chlorobenzene, bromobenzene and toluene have been used to compute the mutual correlation factor (gab ), the excess molar polarization (ΔP) and the Gibbs free energy of mixing (ΔGab ) using Winkelmann-Quitzsch equations. The results are utilised in interpreting the molecular association and hence the nature of clusters involving unlike molecules.

Dipolar Association in Binary System: MIBK in Carboxylic Acids

The dielectric constant (e) of the binary mixtures of MIBK with some carboxylic acids viz. acetic acid, propanoic acid and butyric acid is measured at 303.16 K at 455 kHz. The experimental data are used to compute the excess dielectric constant (Δe), mutual correlation factor (g ab), excess molar polarization (ΔP) and excess free energy of mixing (ΔG ab) in these mixtures.

Evaluation of linear correlation factor in dilute binary mixtures: Alcohols and amines with non-polar solvents

Linear correlation factor in very dilute solutions (mole fraction < 0.1) of binary mixtures of alcohols and some amines in three nonpolar solvents, i.e. benzene, carbon tetrachloride and p-xylene is estimated at 301 K and extrapolated to zero concentration of the solute. It is found to increase in the mixtures containing alcohol while it decreases to a low positive value in the mixtures containing amines.

Dielectric studies of hydrogen bonded complexes of butanols with aniline and pyridine

Abstract The results of dielectric polarization study at radio freqency of 455 kHz at 303.16K on 1:1 H-bonded molecular complexes of i-butanol + aniline/pyridine, n-butanol+aniline/pyridine and t-butanol+aniline/pyridine have been reported. The dipole moment of the complex ( μ ab ), interaction dipole moment (Δμ) and induced polarization P ab for thermodynamically the most favoured geometry of 1:1 complexes in these systems were evaluated from bond angle data. The result shows that the polarization effect dominates in all the complexes studied and that the higher order complexation is not observed.

Dipole moment studies of n-butanol, i-butanol and t-butanol with chlorobenzene complexes

Abstract The dipole moments of H-bonded complexes of n-butanol, i-butanol and t-butanol with chlorobenzene in benzene were investigated from dielectric measurements at 455 kHz and at temperature 303.16 K. The dipole moment of the complex (μab), interaction dipole moment (Δμ) and induced polarization (Pab) for thermodynamically most favoured geometry of 1:1 complexes in these systems were determined. The results shows that the complexation is due to charge redistribution effect in all cases studied and the tendency of complex formation is maximum in n-butanol system.

Thermally Activated Flux Creep and Percolative Conduction in YBa2Cu3O7-y/Ag Composite Thick Films

Temperature-dependent electrical resistivity of a set of YBa2Cu3O7/Ag composite thick films prepared by a reaction diffusion technique was analyzed to determine activation energy. Both measurement current and magnetic field were varied to study ρ vs T characteristics. The applied magnetic field and the measurement current tilt the potential profile that reduces the potential barrier and enhances the vortex motion in the system. The power dependence of activation energy, U0(H) and U0(I) was predicted to obey the power law. From the exponents of the above form, it is observed that the effect of current is dominant over that of the applied magnetic field in reducing the activation energy. A percolative nature of current conduction is explained through the current-controlled tailing of the resistivity transition near Tc0.