An integrated approach to the key parameters in methanol-to-olefins reaction catalyzed by MFI/MEL zeolite materials

Identification of the catalyst characteristics correlating with the key performance parameters including selectivity and stability is key to the rational catalyst design. Herein we focused on the identification of property-performance relationships in the methanol-to-olefin (MTO) process by studying in detail the catalytic behaviour of MFI, MEL and their respective intergrowth zeolites. The detailed material characterization reveals that both the high production of propylene and butylenes and the large MeOH conversion capacity correlate with the enrichment of lattice Al sites in the channels of the pentasil structure as identified by 27Al MAS NMR and 3-methylpentane cracking results. The lack of correlation between MTO performance and other catalyst characteristics, such as crystal size, presence of external Bronsted acid sites and Al pairing suggests their less pronounced role in defining the propylene selectivity. Our analysis reveals that catalyst deactivation is rather complex and is strongly affected by the enrichment of lattice Al in the intersections, the overall Al-content, and crystal size. The intergrowth of MFI and MEL phases accelerates the catalyst deactivation rate. (C) 2022, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.

Automated summary

Identification of catalyst characteristics correlating with key performance parameters is crucial for rational catalyst design. This study focused on the methanol-to-olefin process and identified that enrichment of lattice Al sites in the channels of the pentasil structure is associated with high propylene and butylenes production as well as large MeOH conversion capacity. Other catalyst characteristics, such as crystal size and presence of external Bronsted acid sites, were found to have less pronounced role in defining propylene selectivity. Catalyst deactivation was found to be complex and strongly influenced by the enrichment of lattice Al in the intersections, overall Al-content, and crystal size. The intergrowth of MFI and MEL phases accelerated catalyst deactivation rate.