Synthesis, characterization of hierarchical ZSM-5 zeolite catalyst and its catalytic performance for phenol tert-butylation reaction

A hierarchical ZSM-5 zeolite was prepared under hydrothermal conditions through polystyrene (PS) colloidal spheres and tetrapropylammonium hydroxide (TPAOH) dual templates method. The physical and acid properties of the hierarchical ZSM-5 zeolite were characterized by XRD, SEM, N2 adsorption, 27Al-MAS NMR and NH3-TPD techniques. Catalytic tests show that the hierarchical ZSM-5 zeolite catalyst exhibits high catalytic activity for alkylation of phenol with tert-butanol. The high phenol conversion and 2,4-di-TBP selectivity are mainly assigned to the presence of the hierarchical porosity and strong acidity of the pore walls. The macropores offer easier transport and access to the active sites and the macroporous walls built by nano-ZSM-5 crystals provide the acidic sites for reaction.