Zhejiang Key Laboratory of Alternative Technologies for Fine Chemicals Process, Shaoxing University, Shaoxing 312000, China.
Zhejiang Key Laboratory of Alternative Technologies for Fine Chemicals Process, Shaoxing University, Shaoxing 312000, China.
Int J Biol Macromol. 2014 Jul;68:189-97. doi: 10.1016/j.ijbiomac.2014.04.035. Epub 2014 Apr 24.
A novel palladium supported on chitosan porous membrane heterogeneous catalyst has been prepared by freeze-drying of Pd(2+)-crosslinked chitosan gel solution. The prepared membrane catalyst has three-dimensional porous structure (porosity: >70%). The crosslinking effects of Pd(2+) to chitosan were good for the improvement of the mechanical properties and thermal stabilities. Pd(2+) cations have been shown not only as the crosslinker, but also as the catalytic active sites. The reductive palladium species of the recycled membrane catalysts was found in the nanometer scale (20-40nm). Excellent cross-coupling yields were achieved using as low as 0.12mol% palladium catalyst loading for the Heck-type reaction of aromatic halides with acrylates. The catalyst could be recycled six times without obvious decreased conversion.
一种新型的壳聚糖负载钯多孔膜非均相催化剂通过冷冻干燥交联的壳聚糖凝胶溶液制得。所制备的膜催化剂具有三维多孔结构（孔隙率：>70%）。Pd(2+)对壳聚糖的交联作用有利于提高其力学性能和热稳定性。Pd(2+)阳离子不仅作为交联剂，而且作为催化活性中心。发现回收膜催化剂中的还原钯物种在纳米尺度（20-40nm）。在芳基卤化物与丙烯酸酯的 Heck 型反应中，使用低至 0.12mol%的钯催化剂负载量即可获得优异的偶联产率。该催化剂可循环使用六次，转化率没有明显下降。
