Preparation, surface acidity and catalytic performance of Beta/ZSM-5 composite molecular sieve

Abstract

• Beta/ZSM-5 was synthesized by seeding method. • The crystal structure and surface acidity of the composites were adjusted by changing the secondary crystallization time. • The propylene oxide rearrangement over composite molecular sieve was affected by acid type and acid amount. Beta/ZSM-5 composite molecular sieves were successfully prepared by seeding method and characterized by XRD, FTIR, BET, NH 3 -TPD, Py-FTIR. The crystal structure and surface acidity of the samples can be adjusted by changing the crystallization time. Beta/ZSM-5 shows good catalytic performance for the rearrangement of propylene oxide. The results show that when the crystallization time is 24 h, the proportion of BEA type and MFI type structure in the sample reaches equal, and the amount of Lewis acid is 18.1 mmol/g, while that of B acid is only 6.48 mmol/g, which is more conducive to the rearrangement of epoxy propane to produce propionaldehyde.