Volumetric, isentropic compressibility and viscosity coefficient studies of binary solutions involving amides as a solute in aqueous and CCl4 solvent systems at 298.15 K

The experimental measurements of the density, speed of sound and viscosity coefficient in binary solutions involving water and CCl4 as solvents and formamide, N-methylformamide, N, N-dimethylformamide, N-methylacetamide and N, N-dimethylacetamide as solute in the concentration range (0.00992 mol.kg(-1) to 1.07890 mol.kg(-1)) at 298.15 K are reported. The data are used to obtain the isentropic compressibility (beta(s)) of solutions and Jones-Dole viscosity B and D coefficients for solutes. The derived properties like apparent molar volume (V-phi) and apparent molar isentropic compressibility (K-phi) of amides at different concentrations are evaluated. The data of limiting apparent molar volume (V-phi(0)) and apparent molar isentropic compressibility (K-phi(0)) for amides in both solvent systems (H2O and CCl4) and their concentration variation are examined to study the effect of intermolecular H-bond formation (for the amide molecules), hydrophobic interaction effect in water and amide-CCl4 interactions. It has been observed that there is loss of volume and compressibility of amide molecules in transferring them from pure liquid state to water and gain in transferring to CCl4 solutions (non-aqueous solvent) except for dimethylacetamide. The transfer volumes and compressibilities from CCl4 to water are negative and are attributed to H bond formation between solute molecules. The viscosity B coefficients for the amides are found to be high positive in water while they are of small magnitude in CCl4 medium. All these results are discussed on the basis of solute-solvent interaction, hydrophobic interaction in water and H-bond formation possibilities in CCl4. It is proposed that, the dissolution of dimethylformamide in water takes place substitutionally in water cavities with very little volume change. (C) 2018 Elsevier B.V. All rights reserved.