Novel composites of ZSM-5 and MOF as potent acidic catalysts: Study of the role of zeolite characteristics in the catalytic activity

With the aim of benefiting from the catalytic activity of metal organic frameworks and zeolites and the possible synergistic effect between them, two novel composites, composed of MIL-101 and ZSM-5 zeolites with different SiO2/Al2O3 ratios were synthesized via surface functionalization of ZSM-5 zeolites and their hydrothermal treatment with MIL-101 precursors. Characterization of the composites confirmed formation of MIL-101 in the presence of ZSM-5 zeolite. Moreover, it was revealed that the textural properties and acidity of the composite were influenced by SiO2/Al2O3 ratio and the one with lower SiO2/Al2O3 ratio showed higher acidity. The catalytic activity of the composites was then appraised for Knoevenagel condensation reaction under mild reaction conditions. Gratifying, the composites showed high catalytic activity, higher than their individual components, indicating the synergism between ZSM-5 and MIL-101. Broad substrate scope, facile recovery of the catalyst and its high recyclability were other merits of the present protocol.