Abstract
In order to clarify the mode of degradation of ascorbyl monolaurate, kinetic study was made on its decomposition in aqueous solution under aerobic conditions. Thin-layer chromatography (TLC) of its degradation products indicated the presence of lauric acid, that results from hydrolytic cleavage of the ester bond, and other unidentified degradation products. The rate of degradation of ascerbyl monolaurate in aqueous solution was determined at 45°, 60°, and 80° in the pH range of 3.10-10.12 and at the ionic strength of 0.1. The pH-rate profile of the rate of disappearance of ascorbyl monolaurate from an aqueous solution and that of ascorbic acid was determined at 80°. The profiles showed that ascorbic acid is more susceptible to degradation than its monolaurate in the alkaline region. This phenomenon is probably due to either a micelle formation of the latter or a difference in the steric hindrance of molecular structure. The results of kinetic experiment or ascorbyl monolaurate in ethanol-water mixtures indicated that the logarithm of the rate constant varies linealy with the reciprocal of the dielectric constant.
