Amine-bridged periodic mesoporous organosilica nanospheres as an active and reusable solid base-catalyst for water-medium and solvent-free organic reactions

作者：Zhu, Fengxia; Yang, Didi; Zhang, Fang; Li, Hexing^*

来源：Journal of Molecular Catalysis A: Chemical , 2012, 363: 387-397.

DOI：10.1016/j.molcata.2012.07.015

• Amine-bridged PMO nanospheres
• Short and straight mesoporous channels
• Solid base-catalyst
• Water-medium and solvent-free organic reactions
• Green chemistry

An amine-bridged periodic mesoporous organosilica catalyst in uniform nanospheres (similar to 85 nm) (NH-PMO-NS) was synthesized by surfactant-directed co-condensation between amine-bridged silane and tetraethoxysilane (TEOS). As-prepared NH-PMO-NS contained short and straight mesoporous channels with amine-groups integrally incorporated into silica walls. In water-medium Knoevenagel condensation and solvent-free Henry reactions, this catalyst exhibited much higher activity and selectivity than both the common amine-bridged PMO (NH-PMO-com) with irregular shape synthesized by traditional method and the amine-functionalized MCM-41 in nanospheres (NH-MCM-NS) prepared by grafting amine-groups onto the pore surface. In addition, it displayed comparable catalytic efficiencies with the homogeneous base-catalyst (diethylamine), and could also be easily recovered and used repetitively. Based on the structural characterizations and kinetic studies, the high catalytic activity and selectivity were ascribed to the short and straight mesoporous channels in nanospheres with amine-groups incorporated into silica walls. The accessible basic catalytic sites may facilitate the diffusion and thus, promoted the adsorption of organic reactant molecules, leading to the enhanced activity and selectivity.

• 出版日期2012-11
• 单位淮阴师范学院; 上海电力大学