Sn-Beta was post-synthetically modified with various cations such as Li⁺, Na⁺, K⁺, Cs⁺, and NH₄ ⁺. During the modification process, the ion-exchange of the cations with silanol groups occurred along with a reversible change between “closed” and “open” Sn sites through hydrolysis of the Si–O–Sn bonds. The IR study showed that Sn-Beta had weak Brønsted acid sites, which were passivated by the ion-exchange, in addition to the Lewis acid sites and that surprisingly, basic sites were formed on the modified zeolites. The ion-exchange with a small amount of Li⁺, Na⁺ and NH₄ ⁺ was effective for suppressing side-reactions, leading to an improvement in selectivity to caprolactone in the Baeyer–Villiger oxidation of cyclohexanone with H₂O₂. The modification of Sn-Beta with such cations also effectively enhanced the catalytic activity in the Baeyer–Villiger oxidation of 2-adamantanone.

Selective oxidation of methane to methanol with H₂O₂ over an Fe-MFI zeolite catalyst using a sulfolane–water mixture solvent achieved a high productivity of liquid products and a high methanol selectivity.

In addition to the original preparation route of the RTH-type zeolites using 1,2,2,6,6-pentamethylpiperidine (PMP) as an organic structure directing agent (OSDA), we have found that simpler organic amines such as N-methylpiperidine and pyridine can be used as alternative OSDAs in place of PMP. Furthermore, we have established a synthesis method for preparing the RTH-type zeolites without using any OSDAs. In this study, RTH-type aluminosilicates were synthesized with different types of OSDA or without using any OSDAs. The obtained zeolites synthesized with different preparation methods were characterized by using various techniques, especially high-resolution ²⁷Al MAS NMR and in situ FT-IR techniques using CO adsorption. The relationship between the preparation method and the catalytic performance in the methanol to olefins (MTO) reaction was discussed. Finally, the distribution of Al species in the RTH-framework was clarified.