Synthesis of short-channeled amino-functionalized SBA-15 and its beneficial applications in base-catalyzed reactions
Amino-functionalized-SBA-15 catalysts with nanostructured hexagonal platelet morphologies were synthesized directly by using microwave synthesis from the hydrolysis and co-condensation of aminopropyltriethoxysilane (APTES) and sodium metasilicate under a strong acidic condition with the Pluronic P123 triblock copolymer as a structure-directing agent. The amino-functionalized-SBA-15 catalysts were proven by SEM and TEM techniques to have very short channels in the range of 200–300 nm perpendicular to the hexagonal platelet morphologies. These short-channeled catalysts were proven to be effective heterogeneous catalysts in liquid-phase reactions such as Knoevenagel and Claisen-Schmidt condensations as well as in Henry reaction. They exhibited greatly improved catalytic activities over the typical fibrous type SBA-15 catalyst having long channels. Obviously, the easy diffusion and rapid mass transfer of substrate into the short channel mesopores played important roles in the significant improvement in the catalytic activities.
Graphical abstractShort-channeled amino-functionalized-SBA-15 catalysts, NH2pr(x)-SBA-15, were synthesized. Their beneficial effects on base-catalyzed reactions were studied. The catalytic results showed that short-channeled catalysts showed much higher catalytic activity as well as higher selectivity to bulky product as compared to the corresponding amino-functionalized-SBA-15 catalysts having long channels.Figure optionsDownload full-size imageDownload as PowerPoint slide
Journal: Applied Catalysis A: General - Volume 350, Issue 2, 30 November 2008, Pages 244–251