Oxidation of Ascorbic Acid by Oxygen with Cupric Ion as Catalyst

The experiments described in the present paper were carried out for the purpose of obtaining more specific information concerning the nature of the copper-catalyzed oxidation of ascorbic acid. All of the experiments reported here were carried out under such conditions that steps involving oxygen as a reactant were not rate determining. Furthermore, in order to avoid the possibility of cupric ion complexing with buffers no buffers were used, but instead the hydrogen-ion concentration was maintained at an effectively constant value throughout the course of the reaction by the addition of a comparatively large amount of acid at the start.