Tuning the Design of Aminosilica Materials for Enhancing Acid-Base Cooperative Interactions for the Aldol Reaction and Condensation

Cooperative interactions have the potential to enhance the catalytic performance for aminosilica materials. The key challenge is identifying how to design the cooperative interactions. Previous work has demonstrated that cooperative interactions between amines and silanols can be designed on materials such as SBA-15. Our recent work has demonstrated that the conventional method to produce SBA-15 does benefit from cooperative interactions amine-silanol interactions, but the typical synthesis methods for these materials result in only 30% of the sites being active. In this work, we will describe how the fraction of catalytic sites can be increased to over 70% through reducing the micropore volume of SBA-15 and limiting amine-silanol interactions during grafting. The resultant materials have catalytic activities that are more than double the activities of conventional materials. We extend these methods to produce materials with different pore sizes that are tested for catalytic activity in the nitroaldol reaction, revealing important new insights on the effect of the pore size. Through these investigations, we will establish a better understanding of the cooperative interactions occurring in aminosilica catalytic materials.