Publication Date:
2011-09-28
Description:
Mordenite framework inverted (MFI)-structure catalysts with framework trivalent metal cations and extra-framework metal cations were prepared by the sublimation method to synthesize pyridine and picolines. The results show that the sublimation treatment of volatile metal halides, i.e., GaCl 3 and FeCl 3 , consumes the silanol groups of the parent sample. Most of the Ga cations are incorporated into the zeolite framework, which produces hydroxyl groups and dramatically enhances the proportion of Brönsted acid sites. At the same time, a large number of Fe cations exist in the extra-framework, causing an increase in the proportion of Lewis acid sites. The increased acid amount and strength effectively improve the activity and stability of the catalyst. Moreover, the generated stronger acid sites increase the selectivity of pyridine. The Ga cations of the modified zeolite can promote the dehydrogenation step for pyridine synthesis, which markedly increases the pyridine selectivity. The sublimation of volatile metal halides was employed for tailoring a high-Si/Al MFI-structure zeolite to produce a catalyst for the gas phase synthesis of pyridine and 3-picoline. After sublimation treatment, the metal cations were incorporated into the framework and extra-framework of the zeolite. The modification effectively improved the activity and stability of the catalyst.
Print ISSN:
0930-7516
Electronic ISSN:
1521-4125
Topics:
Chemistry and Pharmacology
,
Process Engineering, Biotechnology, Nutrition Technology
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