Ultrasonic relaxation studies of solutions of triethylamine and 3,3-diethylpentane in 2-propanol as a function of temperature

Ultrasonic absorption data obtained over the frequency range 5–95 MHz by the pulse method are reported for 3,3-diethylpentane and triethylamine in 2-propanol in the temperature range 0–25°C. Data are also reported for triethylamine as a function of concentration. A relaxation is observed under all experimental conditions and is associated with the equilibrium between rotational isomers as previously proposed by other workers. The energy parameters associated with a two-state model for the isomers are evaluated and compared with previous results for the pure liquids. The difference in these parameters for the compounds dissolved in 2-propanol is partly attributed to the difference in the dynamics of rotation of an ethyl group about a carbon-carbon and carbon-nitrogen bond.