Determination of the side-products formed during the nitroxide-mediated bleach oxidation of glucose to glucaric acid

The side products formed in the TEMPO-mediated oxidation of glucose to glucaric acid were determined by GC. Next to glucaric acid, gluconic acid, the intermediate in the oxidation, the degradation products, oxalic acid, tartronic acid, meso(erythraric) and DL-threaric (tartaric) acid were detected. Chiral GC determined the DL-tartaric acid to be non-racemic mixtures of L- and D-tartaric acids, with inverse D/L-ratios depending on the oxidation of D- or L-glucose. The origin of all degradation products is rationalized. This study details a fast screening method to optimize the reaction conditions toward minimal degradation. (C) 2002 Published by Elsevier Science Ltd.