Mechanistic Insights into Sugar Racemization and Oxidative Degradation via Fenton and Alkaline Peroxide Systems

This study explores the oxidation and racemization of selected C5 and C6 sugars using hydrogen peroxide (H2O2) in alkaline and Fenton reaction conditions. The sugars studied include D-Glucose, D-Fructose, D-Mannose, D-Xylose, D-Lactose, D-Arabinose, D-Cellobiose, Sucrose, and D-Galactose. Oxidation reactions were conducted using both Fenton’s reagent and NaOH/H2O2 to examine product formation, yield distribution, and stereochemical transformations. Under alkaline conditions, sugars primarily oxidized to yield sodium formate and hydrogen, with the minimal formation of intermediate sugar acids. Excess alkaline conditions further promoted the rapid degradation of sugars to sodium formate and hydrogen as primary products, indicating the strong influence of reaction conditions on oxidation pathways. A significant observation was that both alkaline and Fenton oxidation led to racemization, converting optically pure sugars into a racemic mixture of D- and L-enantiomers, thus producing products with zero optical rotation. The generation of L-enantiomers, metabolically inactive in biological systems, has implications for energy yield and biochemical efficiency.