Baljeet Singh Patial, Study of Acoustic Nature of Tetrapentylammonium Bromide in N,N-Dimethyl-Ethylmethyl Ketone Systems at Different Temperatures, ILCPA Volume 48, International Letters of Chemistry, Physics and Astronomy (Volume 48)
https://www.scipress.com/ILCPA.48.103
Abstract:
    Ultrasonic velocity, viscosity and density studies on solution of tetrapentylammonium bromide (Pen<sub>4</sub>NBr) in N,N-dimethylformamide, ethylmethylketone (EMK) and DMF-EMK solvent mixtures containing 0, 20, 40, 60, 80 and 100 mol % of DMF at 298, 308 and 318K have been reported. From the velocity, viscosity and density data values, various parameters namely, the adiabatic compressibility (β), Intermolecular free length (L<sub>f</sub>), specific acoustic impedance (Z), free volume (V<sub>f</sub>), internal pressure (π<sub>i</sub>) and relaxation time (τ) have been calculated. All these parameters have been discussed separately to throw light on the solute-solvent and solvent-solvent interactions.
Keywords:
    Adiabatic Compressibility, Free Volume, Intermolecular Free Length, Internal Pressure, Relaxation Time, Specific Acoustic Impedance