Effect of Pressure and Temperature on Rotational Isomeric Relaxation in Ethyl Acetate

Abstract

Ultrasonic absorption measurements have been made in liquid ethyl acetate over a temperature range from 10° to 80°C and up to a pressure of 1000 atm. Evidences of a rotational isomeric relaxation were observed, and the relaxation frequency fr was calculated as a function of temperature and pressure. The relaxation frequency was found to be independent of pressure (within experimental error) up to 1000 atm and to increase exponentially with increasing temperature. The activation enthalpy was found to be in good agreement with that found previously by Pinkerton. The calculated values of fr at 40°C are also in good agreement with Pinkerton and those of Kal'yanov and Nozdrev. However, the data taken at constant density as a function of temperature are in complete disagreement with the conclusions of Kal'yanov and Nozdrev who find that at constant density fr is independent of density but dependent on temperature.