Kinetics of oxidation of reducing sugars by catalytic amount of osmium(VIII) in presence of periodate

The kinetics of oxidation of some reducing sugars viz. glucose, galactose, fructose, maltose, and lactose by osmium(VIII) in presence of sodium metaperiodate in alkaline medium have been investigated. The reactions are zero order in periodate. The order of reaction in substrate and OH − decreases from unity to zero at higher [substrate] or [OH − ], respectively. Rate of oxidation is proportional to [Osmium(VIII)]. Osmium(VIII) serves as an effective oxidant which oxidizes reducing sugars and itself reduces to osmium(VI). Role of IO 4 − is to regenerate osmium(VIII) from osmium(VI). An evidence for the complex formation between osmium(VIII) and reducing sugar has also been obtained.