Ultrasonic Study in Aqueous Solutions of Alcohols with Methoxyl and Propoxyl Groups

Ultrasonic absorption, velocity and density measurements were carried out in aqueous solutions of 1-methoxy-2-propanol and 3-(3-methoxypropoxy)propanol as a function of their concentrations at 25°C. A single ultrasonic relaxational phenomenon was observed in both solutions in the frequency range from 6.5 to 220 MHz. The cause was attributed to a perturbation of an equilibrium associated with the solute solvent interaction, AB(Remark: Graphics omitted.)A+B, from the concentration dependences of the relaxation frequency and the amplitude of the relaxational absorption. The rate and thermodynamic parameters were determined for the above process. It was found that the methoxyl group introduced in alcohol molecule acted as a water structure breaker while the propoxyl group promoted the water structure. Speculation of excess ultrasonic absorption in various monohydroxy alcohol aqueous solutions was carried out from the present data. In order to further confirm the participation of the solvent water molecule in ...