Ultrasonic velocities and isentropic compressibilities of some symmetrical tetraalkylammonium salts in N,N-dimethylacetamide at 298.15 K

Ultrasonic velocities of tetrapropylammonium bromide (Pr4NBr), tetrabutylammonium bromide (Bu4NBr), tetrapentylammonium bromide (Pen(4)NBr), tetrahexylammonium bromide (Hex(4)NBr), tetraheptylammonium bromide (Hep(4)NBr), and tetraoctylarnmonium bromide (Oct(4)NBr) in N,N-dimethylacetamide have been measured at 298.15 K. Apparent molar isentropic compressibilities kappa(phi) of these electrolytes were derived from these data supplemented with their densities. The limiting apparent molar isentropic compressibilities kappa(phi)degrees were obtained by extrapolation from the plot of kappa(phi) vs. the square root of the molality. The kappa(phi)degrees values of the electrolytes were split into approximate limiting ionic compressibilities kappa(phi+/-)degrees on the basis of the assumption that kappa(phi)degrees(Br-) = 0. The results have been interpreted in terms of specific constitutional and structural factors of the solvent molecules and of sPlute ions. (C) 2003 Elsevier B.V. All rights reserved.