Excess volumes and ultrasonic velocities of some amide +water systems at 298.15 K

Abstract

Excess volumes (<i>V</i>^E) and isentropic compressibilities (<i>K</i>_s) have been determined at 298.15 K for the systems water + N-methylformamide, + N,N-dimethylformamide, + N-methyl-2-pyrrolidinone and + N,N-dirnethylacetamide. Excess volumes have been measured directly by means of a successive-dilution dilatometer and isentropic compressibilities have been computed from experimentally determined densities and velocities of sound. The speed of sound u has been obtained at 4 MHz in the whole composition range at 298.15K, using sing-around technique. Excess volumes and deviation in isentropic compressibility are all negative over the whole composition range. The values of both <i>V</i>^E and <img src='/image/spc_char/delta.gif' border=0><i>K</i>_s have been discussed in terms of intermolecular interactions between the mixing component of the binary mixture.