Influence of Silica Source on Zeolite Synthesis in the Presence of 1-Butanol
Toshikazu KUBOTA, Yasunori OUMI, Toshiya UOZUMI and Tsuneji SANO*
School of Materials Science, Japan Advanced Institute of Science and Technology; Tatsunokuchi, Ishikawa 923-1292 Japan
Synthesis of high-silica zeolites in the presence of 1-butanol (n-BuOH) was conducted under various conditions to explore the role of silica source, aging time, and n-BuOH.
It was found that the solubility of the silica source in the aqueous phase was a critical factor for the formation of zeolite precursor when KOH was employed as an alkali source. MFI (ZSM-5) type zeolites were obtained when fumed silica with small BET specific surface area was employed, whereas TON (Theta-1) type zeolites were formed when fumed silica with large BET specific surface area was employed. It was also found that the addition of n-BuOH suppressed the formation of cristobalite. This is probably due to the reduction of the Si concentration in the aqueous phase of the synthesis gel. FT-IR and 13C CP MAS NMR measurements of as-made zeolites suggested that n-BuOH molecules were occluded in the zeolitic pores of TON and MFI type zeolites at the initial stage of crystallization.
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