ACOUSTIC AND EXCESS THERMODYNAMICAL STUDIES ON 1-ALKANOLS WITH DMA IN CYCLOHEXANONE AT DIFFERENT TEMPERATURES

Authors: S.Thirumaran* and J. Ramesh

*Department of Physics, (D.D.E.), Annamalai University, Annamalainagar – 608 002, India; E-mail: thirumaran64@gmail.com

The ultrasonic velocity, density and viscosity have been measured for the mixtures of 1–alkanols, namely, 1–propanol,1–butanol, and 1–pentanol with N,N-dimethyl acetamide (DMA) in cyclohexanone at 303, 308 and 313K. The experimental data have been used to calculate the acoustical parameters, namely excess adiabatic compressibility (b^E), excess free length (L_f^E), excess free volume (V_f^E) and excess internal pressure (p_i^E). These excess values predict the dissociation of hydrogen bonded structure of 1- alkanols and also the rupture of hydrogen bonds in the associated structure of 1-alkanols when it is mixed with DMA. It is also interesting to note that the elevation of temperature too induces the rupture of hydrogen bonds of unlike molecules.

Keywords : rupture of hydrogen bonds, dipole-dipole interactions, excess free volume, polar liquids, aprotic