Proton transfer in some model equilibria studied by the ultrasonic method

Abstract

The rate constants in the equilibria involving proton transfer between heterocyclic amines and water and also some amines and organic acids in aqueous solution have been studied using the ultrasonic relaxation method. The dynamics of proton transfer do not appear to depend on the conformational properties of the amines. The well established relationship between the rate constants and the difference in pK between the proton acceptor and donor molecule are obeyed. Other aspects studied include the determination of the activation energy of a diffusion controlled step in one of the equilibria and the isotope effect. Finally attempts were made to calculate some of the rate constants.