Ultrasonic and volumetric study of binary mixtures of benzyl alcohol with Amides

The density (rho) and ultrasonic speed (u) in binary mixtures of benzyl alcohol (BA) with formamide (FA), N-methylacetamide (NMA), N,N-dimethylformamide (DMF), and N,N-dimethylacetamide (DMA), including those of pure liquids, were measured at 35 degreesC over the entire composition range. The isentropic compressibility (k(s)), deviations in isentropic compressibility (DeltaK(s)) and ultrasonic speed (Deltau) from linear dependence on the composition, excess volume (V-E), apparent molar isentropic compressibility (K-phi,K-s) and apparent molar volume (V-phi) of an-tides in benzyl alcohol were calculated. The variation of these parameters with composition of the mixtures suggests that the strength of interaction (BA-FA) < (BA-BA) or (FA-FA), whereas the interaction (BA-substituted amide (NMA, DMF, and DMA)) > (BA-BA) or (amide-amide). Moreover, the values of Deltak(s) are found to depend on the positions of the methyl groups, while those of V-E seem to depend on the number of such groups in the amide molecule.