Ultrasonic absorption in n-alcohol + organic solvent mixtures

Abstract

Ultrasonic absorption measurements have been carried out in organic solvent + alcohol mixtures. For all of the systems studied the plots α/f² against x(mol fraction) display a sharp maximum for x < 0.1 except when solvent molecules associate with each other and with alcohol molecules through H-bonds. The influence of the alcohol chain length and of the solvent nature on the amplitude and position of the absorption peak has been studied. The results suggest that the excess absorption is due to an aggregation equilibrium (e.g., trimerization) between alcohol molecules. The expressions for the relaxation frequency f_R and for the excess absorption α/f² obtained following a classical procedure for the trimerization equilibrium account qualitatively for all of the experimental results obtained in this work and by others workers.