Synthesis of short-channeled amino-functionalized SBA-15 and its beneficial applications in base-catalyzed reactions

Short-channeled amino-functionalized-SBA-15 catalysts, NH 2pr( 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. ▪ 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.