Ultrasonic investigation in the eutectic mixture acetamide + sodium thiocyanate

Abstract

The attenuation of ultrasonic longitudinal waves in the eutectic mixture CH₃CONH₂+ NaCNS has been measured in the temperature range 255.2–303.2 K and frequency range 5–105 MHz, and the velocities of propagation at 298.4 K for 5 and 15 MHz have been obtained. A distinct structural relaxation process was found in the measured area. Comparing these results with previously reported shear results (G. Berchiesi, G. Vitali, P. Passamonti and R. Płowiec, J. Chem. Soc., Faraday Trans. 2, 1983, 79, 1257), the variation of the loss modulus, M″, as a function of frequency was determined. Agreement was found with theoretical expectations; however, the influence of the eutectic relaxation process, which takes place in the same area, is evident. Additional shear measurements performed at 10 MHz showed this influence to be stronger than at the higher frequencies reported previously.