Samenvatting
A novel method to remove aluminium from the framework of as-synthesized zeolite crystals is presented. Hydrothermal treatment in an aqueous ammonium fluoride solution leads to selective dealumination of ZSM-5–TPA zeolite crystals. The optimized dealumination procedure results in 30–50% removal of Al atoms without significant structural degradation. It is also shown that template stabilization by tetrapropylammonium cations or pentaerythritol plays a key role in the developed method, as template-free ZSM-5 crystals, treated under similar conditions, lose their crystallinity and microporosity. The mild dealumination was applied to as-synthesized hierarchical mordenite zeolite to obtain a much more effective catalyst in hydroconversion of heavy paraffins. The optimized Pd/MOR catalyst showed a low selectivity to cracked products up to 60% of n-hexadecane conversion with product distribution close to the ideal hydrocracking regime.
Originele taal-2 | Engels |
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Pagina's (van-tot) | 4239-4247 |
Aantal pagina's | 9 |
Tijdschrift | Catalysis Science & Technology |
Volume | 9 |
Nummer van het tijdschrift | 16 |
DOI's | |
Status | Gepubliceerd - 21 aug. 2019 |