Bio-inspired immobilization of metal oxides on monolithic microreactor for continuous Knoevenagel reaction

Abstract A facile method is reported to construct monolithic microreactor with high catalytic performance for Knoevenagel reaction. The microreactor is based on hierarchically porous silica (HPS) which has interconnected macro- and mesopores. Then the HPS is surface modified by pyrogallol (PG) polymer. Al(NO 3 ) 3 and Mg(NO 3 ) 2 are loaded on the surface of HPS through coordination with –OH groups of PG. After thermal treatment, Al(NO 3 ) 3 and Mg(NO 3 ) 2 are converted Al 2 O 3 and MgO. The as-synthesized catalytic microreactor shows a high and stable performance in Knoevenagel reaction. The microreactor possess large surface area and interconnected pore structures which are beneficial for reactions. Moreover, this economic, facile and eco-friendly surface modification method can be used in loading more metal oxides for more reactions.