Multilamellar MFI-Type Zeolites: The Effect Silica Sources and of Heteroatoms on Their Properties

Hierarchical zeolites do not only offer the possibility of reducing mass transfer limitations, but they also allow the catalytic conversion of large molecules over zeolites. However, the extra porosity in hierarchical zeolites often leads to low selectivity of the product. Thus, introducing the mesopores with optimum size is very crucial in the synthesis of hierarchical zeolites, because this will minimize the mass transport limitations and simultaneously prevent the formation of unwanted bulky products. Therefore, novel synthesis routes are required to prepare hierarchical zeolites with tunable porosity, e.g., the preparation of multilamellar MFI-type zeolites [1]. In this contribution, recent advances in the synthesis of MFI nanosheets under different experimental conditions will be discussed. In addition, the influence of silica and aluminium source as well as the kind and the content of heteroatoms like aluminium in tuning the textural and the catalytic properties of this material will be in the focus of this work.

Nanosheets of MFI zeolite with Si/Al of 25, 100 and infinity were synthesized under static conditions and tumbling conditions. The influence of different synthesis parameters like content of the heteroatoms, alkalinity and aluminium source were studied. The catalytic cracking of cumene and di-isopropylbenzene were chosen as test reactions to characterize the effect of the incorporation of the heteroatoms.

 

References:

[1] M. Choi, K. Na, J. Kim, Y. Sakamoto, O. Terasaki, R. Ryoo, Nature, 461 (2009) 246.