Issue 10, 2000

Kinetics and mechanism of the chromium(VI) oxidation of methyl α-D-glucopyranoside and methyl α-D-mannopyranoside

Abstract

The oxidation of methyl α-D-glucopyranoside (Glc1Me) and methyl α-D-mannopyranoside (Man1Me) by CrVI yielded Cr3+ and methyl α-D-glycofuranurono-6,3-lactone as final products when an excess of the methyl glycoside over CrVI was used. The redox reaction occurs through CrVI → CrIV → CrIII and CrVI → CrV → CrIII paths, the CrVI/CrIV reduction being the slow redox step. The complete rate laws for the redox reactions are expressed by: −d[CrVI]/dt = kGH[H+]2[Glc1Me][CrVI], where kGH = (6.75 ± 0.05) × 10−3 M−3 s−1; and −d[CrVI]/dt = (kM0 + kMH [H+]2)[Man1Me][CrVI], where kM0 = (5 ± 1) × 10−4 M−1 s−1 and kMH = (6.5 ± 0.2) × 10−3 M−3 s−1, at 40 °C. In acid medium, intermediate CrV reacts with the substrate faster than CrVI does. Chromium(V) mono- and bis-chelates were detected by EPR spectroscopy, and the EPR spectra show that the distribution of these species essentially depends on the solution acidity.

Supplementary files

Article information

Article type
Paper
Submitted
21 Oct 1999
Accepted
22 Feb 2000
First published
20 Apr 2000

J. Chem. Soc., Dalton Trans., 2000, 1617-1623

Kinetics and mechanism of the chromium(VI) oxidation of methyl α-D-glucopyranoside and methyl α-D-mannopyranoside

S. Signorella, M. I. Frascaroli, S. García, M. Santoro, J. C. González, C. Palopoli, V. Daier, N. Casado and L. F. Sala, J. Chem. Soc., Dalton Trans., 2000, 1617 DOI: 10.1039/A908410J

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Spotlight

Advertisements