Design and Synthesis of IFR-Type Zeolites with Controlled Locations of Framework Aluminum with the Aid of Theoretical Calculation

The location of Al in zeolites, a class of crystalline microporous aluminosilicates widely utilized in several applications, is one of the key factors determining their physicochemical properties [1, 2]. Rationally designed synthesis of zeolites with controlled Al locations is one of the ultimate goals in the zeolite syntheses, but is very challenging due to the limitation of analytical techniques and unclarified crystallization mechanisms. In this work, synthesis of zeolite with controlled Al locations has been attempted by selecting an IFR topology as a model zeolite. The computational investigation suggested that its organic structure-directing agents (OSDAs) are likely to be fitted inside the zeolite and slightly change the relative stability of Al sites. IFR-type zeolites synthesized with different OSDAs under an identical condition were characterized by ²⁷Al NMR with the aid of DFT calculations. The results showed that Al locations of IFR-type zeolites can be tuned in accordance with energies derived from zeolite-OSDA complexes. This combined experimental and computational approach would lead to rational synthesis of zeolites with controlled Al locations.

[1] Davis, M. E. Chem. Mater. 2014, 26 (1), 239–245.

[2] K. Muraoka, W. Chaikittisilp, T. Okubo, J. Am. Chem. Soc., doi: 10.1021/jacs.6b01341.