Abstract

ACOUSTICAL AND THERMODYNAMIC STUDIES OF TERNARY LIQUID MIXTURES OF PRIMARY ALKANOLS IN MIXED BINARY SOLVENT AT VARYING TEMPERATURES

Dr. A. Suryanarayana Reddy and M. Satyanarayana*

ABSTRACT

Densities (ρ), viscosities (η) and speeds of sound (U) of ternary liquid mixtures of primary alkanols such as 1-pentanol and 1-hexanol, 1-heptanol and 1- octonal with the fixed binary solvent mixtures of N-N dimethylacetamide (DMA) and diethyl ketone (DEK) (ratio 4:2 respectively) were measured over the entire composition range at 303.15, 308.15 and 313.15K and at normal atmospheric pressure. The observed experimental data have been utilized to evaluate some of the thermo dynamical parameters such as adiabatic compressibility (β), intermolecular free length (Lf ), free volume (Vf ), internal pressure (πi), viscous relaxation time (τ ) and Gibb’s energy (ΔG). The variation of these parameter with composition were discussed from the view point of intermolecular interactions in these mixtures. It was observed that the interaction between DMA (proton acceptor) and 1-alkanols is due to hydrogen bonding. The present study observes that there was a dissociation in the associated structure of 1-alkanols when they are further added with binary solvent mixture (DMA + DEK).

Keywords: Adiabatic compressibility, free length, internal pressure, hydrogen bonding, dipole-dipole interactions, molecular interaction.