Preparation Of Mesoporous Solid Catalyst And Study On Their Properties Of Acid-base Collaborative Catalysis, Asymmetric Hydrogenation Reaction

Traditional homogeneous catalysts have lots of disadvantages due to their difficulty in separation and recovery, which maybe bring about environmental pollution. However, heterogeneous catalysts can solve these problems easily. Mosoporous SBA-15 as a new type of supported materials is widely used in organic ligands modified catalyst and supported metal catalyst. Besides general advantages of reuse, they also possess large surface area and regular pore structure. In particular, mesoporous silica prepared by co-condensation method allows to load uniform distribution on pore surfaces, and to improve catalytic domain of catalysts in the micro-environment because of limiting space of the channels. Therefore, we developed two kinds of mesoporous silica-supported catalysts and studied their detailed catalytic properties.In the first part, a controllable acid-base bifunctionalized mesoporous catalyst was prepared via a co-condensation method and its application in the microwave-promoted Knoevenagel condensation reaction in solid media was investigated. The key feature is that organic silica resource, arylsulfonated amide containing potential acid and base groups, is splitted in an in situ synthetic process to keep acid and base groups in adjacent arrangement and with 1:1 mole ratio on the mesoporous materials. Moreover, a question whether bifunctionalities in adjacent arrangement and match equivalent mole relationship are helpful to elucidate the nature of acid-base cooperativity was investigated.In the second part, a kind of heterogeneous chiral N-sulfonylated diamine-basedη5-Cp*-Ir catalysts with highly ordered dimensional-hexagonal mesostructures were prepared through complexation of [Cp*IrCl2]2 with mesoporous SBA-15 type materials containing chiral (S,S)-TsDPEN groups. During asymmetric hydrogenation of various aromatic ketones, the end-capping mesoporous catalyst exhibited high catalytic activity and enantioselectivity. Furthermore, such a catalyst could be recovered easily and used repetitively seven times without significantly affecting its catalytic activity and enantioselectivity.