Gallium-containing polymer brush film as efficient supported Lewis acid catalyst in a glass microreactor.
Polystyrene sulfonate polymer brushes, grown on the interior of the microchannels in a microreactor, have been used for the anchoring of gallium as a Lewis acid catalyst. Initially, gallium-containing polymer brushes were grown on a flat silicon oxide surface and were characterized by FTIR, ellipsometry, and X-ray photoelectron spectroscopy (XPS). XPS revealed the presence of one gallium per 2-3 styrene sulfonate groups of the polymer brushes. The catalytic activity of the Lewis acid-functionalized brushes in a microreactor was demonstrated for the dehydration of oximes, using cinnamaldehyde oxime as a model substrate, and for the formation of oxazoles by ring closure of ortho-hydroxy oximes. The catalytic activity of the microreactor could be maintained by periodic reactivation by treatment with GaCl3.
Laboratory of Molecular Nanofabrication, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands.
Rajesh
R
Munirathinam
Roberto
R
Ricciardi
Richard J M
RJ
Egberink
Jurriaan
J
Huskens
Michael
M
Holtkamp
Herbert
H
Wormeester
Uwe
U
Karst
Willem
W
Verboom
Lewis acid catalysis; dehydration of oximes; flow chemistry; gallium; microreactors; polymer brushes