Scientific Research and Essays

  • Abbreviation: Sci. Res. Essays
  • Language: English
  • ISSN: 1992-2248
  • DOI: 10.5897/SRE
  • Start Year: 2006
  • Published Articles: 2754

Full Length Research Paper

Kinetics and mechanism of oxidation of sugar and sugar alcohols by vanadium pentoxide

H. K. Okoro1,2* and E. O. Odebunmi2
1Department of Chemistry, Faculty of Applied Sciences, Cape Peninsula University of Technology,  P. O. Box 1906, 7535 Cape Town, South Africa. 2Department of Chemistry, Faculty of science, University of Ilorin, Ilorin, Nigeria.
Email: [email protected]

  •  Accepted: 29 August 2010
  •  Published: 04 September 2010

Abstract

The kinetics of oxidation of sugars and sugar alcohols by vanadium pentoxide (V2O5) in acidic medium have been investigated spectrophotometrically under pseudo-first order conditions and over a wide range of experimental conditions. Each reaction was first order with respect to the substrate and oxidant. The kinetic data for the oxidation by V2O5 solution showed that increase in temperature and sugar concentration increased the rate of the reactions. It was also observed that with increase in pH and KNO3 concentration, the reaction rate decreased with increase in V2O5  concentration with the exception of fructose which showed significant increase in reaction rates .The mechanism of these reactions involved the formation of a 1:1 intermediate complex. The order of reactivities of the sugars was Maltose > Fructose > Sucrose > Glucose > Sorbitol >Mannitol.

 

Key words: Oxidation, sugar and sugar alcohols, kinetics, vanadium pentoxide, activation parameter, intermediate complex, substrate, oxidants, mechanism.