Abstract
The dissolution rates of benzoic acid derivatives in water and in urea solution were measured by rotating disk method. The data of the dissolution in urea solution showed a good agreement qualitatively with the process in which there exist some reaction and the equilibrium is reached rather slowly in the diffusion layer and the solutes are transferred into the bulk solution under non-equilibrium state. That is, the dissolution rate constant, KT, and the saturated concentration, CO, showed the dependence on the lapse of time, and the initial dissolution rate constant, KT(t→o), was almost the same as the value of KT observed on the dissolution in water.
