Kinetic studies on carbohydrates in alkaline conditions. - I. The kinetics of the autoxidation of glucose

Abstract

The autoxidation of glucose and fructose in alkaline solution has been shown to result in the almost quantitative formation of formic and arabonic acids at high oxygen pressures. Under these conditions, the degradation and interconversion reactions are suppressed and the autoxidation reaction reaches a limiting rate. From a general kinetic examination of the autoxidation reaction, evidence is obtained in support of the idea that, at high oxygen pressures, the rate-determining step is that of the parallel formation of two ionic intermediates. The kinetics of the autoxidation can be completely explained in terms of simple reactions of these intermediates. The absolute velocity constants for the formation of the intermediates have been determined from steady-state experiments. Experiments in the non-steady state have enabled the calculation of the concentrations of the intermediates to be made, and thus the velocity constants for their reaction with oxygen can be estimated.