in situ polymerization of poly(vinylimidazole) into the pores of hierarchical zsm-5 zeolite as an acid–base bifunctional catalyst for cascade reaction

Poly(vinylimidazole)/hierarchical zsm-5 has been prepared as a novel and efficient acid–base bifunctional catalyst by a simple method. first, the hierarchical zsm-5 zeolite was synthesized by an indirect method from kit-6 as a silica source. by this method, control of the zeolite crystallization was achieved due to the adjustment transformation processing of amorphous mesoporous silica to zeolite crystal. then, vinylimidazole as a basic part was polymerized by an in situ method into the zeolite’s pores. this acid–base bifunctional heterogeneous catalyst was characterized by ft-ir, tg-dtg, n2 adsorption–desorption, tem, sem, nh3- tpd, and xrd. the catalyst has been applied to one-pot c–c bond formation tandem cascade reactions condensation by the simple method at low temperature. due to the uniform distribution of poly(vinylimidazole) in the micro-meso pores of the hierarchical zeolite reactants, the products easily pass through the catalytic active sites. the co-existence of acidic and basic sites in the structure of the catalyst has a crucial role in the superior activity of this catalyst. moreover, the catalyst showed excellent recyclability and high activity even after 7 runs with only a 10% reduction in activity being detected.