Abstract: Aluminosilicate zeolites EU-1 and ZSM-50 both possess the EUO framework topology which consists of 10-membered ring(MR) channels with deep side-pockets circumscribed 12-MRs. These two compounds can be synthesized in the presence of hexamethonium(HM) and diphenyldimethylammonium ions(DBDMA) as the templates, respectively. Due to the different locations of the Al sites in the frameworks of the two materials, they exhibit different molecular shape selectivity in decane isomerization. In this paper, the structures of EU-1 and ZSM-50 with EUO zeo-type are studied by using molecular dynamics simulation. Based on the calculated interaction energies of host-guest, we can successfully simulate the locations and the numbers of organic molecules in the frameworks of EU-1 and ZSM-50, the possible Si/Al ratios and the energetically favored Al sites in these two compounds. The simulated results are in good agreement with the experimental or reported data. This study also demonstrates that the importance of host-guest charge-density matching principle in the determination of structure.

Key words: Molecular simulation, EUO, High-silica zeolite, Host-guest interaction