Laboratory of Molecular Nanofabrication, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands.
Beilstein J Org Chem. 2013 Aug 16;9:1698-704. doi: 10.3762/bjoc.9.194. eCollection 2013.
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.
聚苯乙烯磺酸盐聚合物刷，生长在微反应器中的微通道内部，已被用于固定镓作为路易斯酸催化剂。最初，含镓的聚合物刷在氧化硅平面上生长，并通过傅里叶变换红外光谱（FTIR）、椭圆光度法和 X 射线光电子能谱（XPS）进行了表征。XPS 表明聚合物刷中的每个镓原子与 2-3 个苯乙烯磺酸盐基团结合。路易斯酸功能化刷在微反应器中的催化活性已通过肉桂醛肟作为模型底物的肟脱水反应和邻羟基肟的闭环形成唑反应得到证明。通过用 GaCl3 周期性地再激活，可以维持微反应器的催化活性。
