Aerobic diol lactonization by Au-nanoparticles supported onto an anion-exchange resin

Authors:  Werner Oberhauser, Alessandro Lavacchi, Francesco Vizza, Laura Capozzoli, Hon Man Lee

Abstract:
Different amounts of AuC_l4 − (i.e. 3.0, 0.5 and 0.1 wt% of Au) were supported onto the anion-exchange resin Dowex Marathon MSA in its chloride form. A successive rapid reduction of the latter anchored Aucompound with NaBH4 combined with anion exchange reactions (i.e. replacement of chloride by acetate or carbonate) gave resin-stabilized Au-nanoparticles (NPs) of comparable size and size distribution. A screening of the catalytic performance of the obtained heterogenous catalysts in the aerobic oxidation reaction of selected diols to lactones in toluene revealed the carbonate form of the resin bearing 0.1 wt% of Au to be the most active catalytic system. The aerobic oxidation of aliphatic diols led to the formation of the corresponding dicarboxylic acid as side-product, which deactivates the catalyst. By washing the deactivated catalyst after each cycle with a solution of Na₂CO₃ in water restored the initial catalyst performance for at least four consecutive catalytic cycles.

Keywords:
Au-nanoparticles
Anion-exchange resin
Aerobic diol lactonization

Published in: Applied catalysis A: General  (Volume 451, Pages 1-288, 31 January 2013)

Publisher: Elsevier

ISSN Information: 0926-860X

Aerobic diol lactonization by Au-nanoparticles supported onto an anion-exchange resin

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