Autocatalyzed oxidation of d-glucitol by alkaline copper (III) periodate complex: A kinetic and mechanistic approach

An autocatalyzed oxidation of d-glucitol (DG) by diperiodatocuprate (III) (DPC) in aqueous alkaline medium at a constant ionic strength of 0.06 mol dm(-3) was studied spectrophotometrically. An autocatalysis was observed by one of the products formed, that is, Cu (II). A 1:2 stoichiometry (DG : DPC) exhibited reaction between the DG and DPC in an aqueous alkaline medium. The reaction was of first order in [DPC] when [DPC] < < [DG], while the order with respect to [DG] and [OH-] was less than unity, whereas periodate had retarding effect on the rate of reaction. Ionic strength had a negligible effect on the rate of reaction. The main reaction products were identified by the spot tests and spectroscopic analysis. The product, Cu (II), catalyzed the reaction with a fractional order. A composite mechanism involving uncatalyzed and autocatalyzed reaction paths was proposed. The activation parameters with respect to slow step of the mechanism and also the thermodynamic quantities were determined and discussed.

Automated summary

The autocatalyzed oxidation of d-glucitol by diperiodatocuprate (III) in aqueous alkaline medium was studied, with Cu (II) observed as a product exhibiting catalytic effect. The reaction exhibited first order kinetics with respect to diperiodatocuprate (III) concentration, while the orders with respect to d-glucitol and hydroxide ion concentrations were less than unity. Periodate ions had a retarding effect on the reaction rate.