Jump to main content
Jump to site search

Issue 6, 2016
Previous Article Next Article

Oxidative coupling of anilines to azobenzenes using heterogeneous manganese oxide catalysts

Author affiliations

Abstract

We herein report the transition metal oxide-catalyzed synthesis of azobenzenes through the oxidative coupling of anilines. An octahedral molecular sieve of manganese oxide, OMS-2, exhibited the best activity and selectivity. Nine examples of symmetric azobenzenes and twenty unsymmetric ones were synthesized with 62–99% conversion and 64–99% selectivity. In the aniline cross-coupling reactions, the difference of the Hammett constants of two substituted groups (Δσ) determines the selectivity to unsymmetric azobenzenes, which are the major products at Δσ < 0.32. In-depth studies reveal that the surface defect sites of the mixed-valence manganese oxide play a key role in facilitating electron transfer and activating molecular oxygen. The single-electron transfer (SET) reaction mechanism is proposed based on electron paramagnetic resonance and X-ray powder diffraction characterization.

Graphical abstract: Oxidative coupling of anilines to azobenzenes using heterogeneous manganese oxide catalysts

Back to tab navigation

Supplementary files

Article information


Submitted
06 Jul 2015
Accepted
27 Oct 2015
First published
30 Oct 2015

Catal. Sci. Technol., 2016,6, 1940-1945
Article type
Paper

Oxidative coupling of anilines to azobenzenes using heterogeneous manganese oxide catalysts

M. Wang, J. Ma, M. Yu, Z. Zhang and F. Wang, Catal. Sci. Technol., 2016, 6, 1940
DOI: 10.1039/C5CY01015B

Social activity

Search articles by author

Spotlight

Advertisements