Two-stage glucose-assisted crystallization of ZSM-5 to improve methanol to propylene (MTP)

Improving propylene selectivity and the lifetime of ZSM-5 catalyst is of great significance for methanol to propylene (MTP) reaction. Hierarchical ZSM-5 zeolites were synthesized by a two-stage crystallization method using glucose as a second template. The structural and surface properties and the morphologies of the prepared samples were characterized by low-temperature N-2 sorption, XRD, Al-27 and Si-29 NMR, FTIR using pyridine probe molecule, NH3-TPD, SEM, and TEM analysis. The two-stage glucose-assisted crystallized ZSM-5 zeolites exhibited large prismatic crystallites, increased intracrystalline mesopores, and reduced acid amount and acid strength, compared with the conventional one-stage crystallized ZSM-5. Methanol to propylene (MTP) reaction at 450 degrees C and methanol WHSV of 3.8 h(-1) revealed that the newly prepared ZSM-5 catalyst, such as ZSM-5-T3, exhibited highest propylene selectivity of 45.2%, propylene to ethylene ratio of 8.4, and C-2(-)center dot C-4(-) selectivity of 63.9%.