日本ゼオライト学会　刊行物 Publication of Japan Zeolite Association

Structure-directing agent such as organic amines is used to synthesize the high-silica zeolite. To clarify the properties of the H⁺-zeolite, it is necessary to understand the structure of as-synthesized zeolites, that is, it is essential to understand the functions in a template and the stabilizing role of the SDA. Solid-state NMR is well suited for investigating the local structure of a particular zeolite with an SDA because these spectra are sensitive to the local structure of the sample.

In this study, we mainly conducted solid-state NMR analysis on high-silica FER with different SDAs, pyridine, and piperidine, and have quantitatively analyzed the SDA that interacts with aluminosilicate. Relaxation experiments show the results correlate with the bonding property in terms of the distance between the zeolite framework and the SDA.

While pyridine mainly acts as a pore filler in FER, piperidine, which is adjacent to the aluminosilicate framework and framework defects, acts as a counter cation to balance the charge. The H⁺-FER synthesized with piperidine shows low hydrothermal stability as compared to that synthesized with pyridine. This can be explained as being a result of the formation of framework defects during the synthesis of the FER with piperidine.