Mesoporous beta zeolite obtained by desilication

Groen, Johan C.; Abelló, Sònia; Villaescusa, Luis A.; Pérez‐Ramírez, Javier

doi:10.1016/j.micromeso.2007.12.025

Cited by 234 publications

(167 citation statements)

References 42 publications

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“…indicates that the desilication with pure NaOH leads to partial amorphisation of Beta zeolite as has been observed previously [19,20]. Low stability of Beta zeolite under NaOH treatment is in a line with previous studies [19] that reported complete amorphisation upon NaOH treatments.…”

Section: Xrd Resultssupporting

confidence: 91%

“…0.7 nm in diameter). The remarkably lower stability of zeolite Beta structure during desilication in comparison to ZSM-5 and mordenite has been reported [20]. Also, the influence of framework aluminum content for controlled desilication was shown [8].…”

Section: Introductionmentioning

confidence: 90%

“…Nevertheless, most of these extracted Al species are able to realuminate on the mesopore surface, resulting in the lowering the Si/Al ratio of the hierarchical [9,10]. Zeolite desilication has been successfully applied to produce a large number of hierarchically structured zeolites MFI [11,12]MTW [13], MOR [14,15], FER [16,17], FAU [18], and Beta [19,20]. Nevertheless, the benefits of desilicated zeolite Beta for catalytic cracking reaction have not been shown in previous studies.…”

Section: Introductionmentioning

confidence: 99%

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Catalytic cracking performance of alkaline-treated zeolite Beta in the terms of acid sites properties and their accessibility

Tarach

Góra‐Marek

Tekla

et al. 2014

Journal of Catalysis

161

111

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The zeolite Beta is considered as a promising additive for FCC catalyst in diesel oil production. In this article, it is shown that hierarchical zeolite Beta obtained by an optimized desilication procedure increases Diesel and propylene yields during gas-oil cracking reaction.The alkaline treatment of zeolite Beta (Si/Al = 22) by desilication with NaOH and NaOH&TBAOH was investigated. The catalytic performance improvement of desilicated zeolite Beta has been rationalized by deep characterization of the samples including X-ray diffraction, low temperature adsorption of nitrogen, solid-state 29 Si MAS NMR and IR studies of acidity. Finally, the catalytic performance of the zeolites Beta was evaluated in the cracking of n-decane, 1,3,5-tri-iso-propylbenzene and vacuum gas oil. It was found that desilication with NaOH&TBAOH ensures the more uniform intracrystalline mesoporosity with the formation of narrower mesopores, while preserving full crystallinity resulting in catalysts with the most appropriated acidity and then, with better catalytic performance.

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Section: Xrd Resultssupporting

confidence: 91%

Section: Introductionmentioning

confidence: 90%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Catalytic cracking performance of alkaline-treated zeolite Beta in the terms of acid sites properties and their accessibility

Tarach

Góra‐Marek

Tekla

et al. 2014

Journal of Catalysis

161

111

View full text Add to dashboard Cite

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“…This should be attributed to the higher stability of framework Al in these materials. 58 The generation of mesoporosity improves the efficiency of Al extraction. 73% and 62% of lattice Al can be removed from the nano-structured MWW-delam and MFI-NS zeolites.…”

Section: Synthesis and Characterizationmentioning

confidence: 99%

Influence of pore topology on synthesis and reactivity of Sn-modified zeolite catalysts for carbohydrate conversions

Graaff

Tempelman

Pidko

et al. 2017

Catal. Sci. Technol.

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A range of Sn-modified MWW, MFI, MOR and Beta zeolites were prepared by a post-synthetic Sn functionalization method and their catalytic properties for sugar conversions were evaluated. The focus of this work was to understand the effect of micropore dimensions and additional mesoporosity on the Sn incorporation and on the catalytic properties. The post-synthetic approach, which involves aciddealumination of the parent zeolite followed by SnCl 4 grafting, is highly efficient for the selective incorporation of lattice Sn sites in wide-pore Beta and MOR zeolites. The modification of the medium-pore MWW and MFI is impaired by the more difficult dealumination and hence the lower efficiency of the Sn incorporation. Hierarchical structuring of the zeolites allows the increase of the Sn loading in the final zeolites. The catalytic properties were assessed in the isomerization and retro-aldolization reactions of glucose and the conversion of 1,3-dihydroxyacetone to methyl lactate. The catalytic results depend strongly on the structural and topological properties of the catalysts as well as on the reactant. Glucose isomerization carried out at a relatively low temperature is mainly limited by strong adsorption of carbohydrates to the active sites. This explains why zeolite nanostructuring had little effect on the catalyst activity, which instead depends mainly on the zeolite topology and the nature of the reactive Sn centers. The influence of pore size is most pronounced for Sn-MWW and Sn-MFI zeolites which are inactive in glucose-to-fructose isomerization, but perform in the higher-temperature retro-aldolization of carbohydrates with an activity similar to that of Sn-Beta. Because of the limited accessibility of the Sn sites inside the 1D MOR pore system, Sn-MOR catalysts were only moderately active in all probe reactions considered.

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“…Desilication has been proven to be effective method to introduce mesoporosity in different types of zeolite structures [5][6][7][8][9][10][11][12][13][14][15][16]. Till now the majority of desilication studies has been done with zeolites of medium Si/Al ratio where aluminium acts as the pore directing agent regulating the extent of the Si extraction.…”

Section: Introductionmentioning

confidence: 99%

Desilication of highly siliceous zeolite ZSM-5 with NaOH and NaOH/tetrabutylamine hydroxide

Sadowska

Góra‐Marek

Drozdek

et al. 2013

Microporous and Mesoporous Materials

127

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Elsevier Sadowska, K.; Góra-Marek, K.; Drozdek, M.; Kustrowski, P.; Datka, J.; Martínez-Triguero, J.; Rey Garcia, F. (2013). Desilication of highly siliceous zeolite ZSM-5 with NaOH and NaOH/tetrabutylamine hydroxide. ABSTRACTThe results of both chemical and XPS analysis pointed out that desilication of highly siliceous ZSM-5 of Si/Al = 164 was more effective in the surface zone than in the bulk, contrary to zeolite ZSM-5 of Si/Al = 31.6. According to the IR studies in parent zeolite the concentration of protonic sites was very close to the concentration of Al indicating that all Al atoms can form Si-OH-Al. The results of our quantitative IR studies strongly support the realumination thesis, i.e. some Al atoms extracted in basic solutions are subsequently reinserted forming new acidic hydroxyls. In desilicated zeolites all Al atoms were able to form protonic sites, however part of them dehydroxylated during the activation of zeolite producing Lewis acid sites according to the stoichiometry: one protonic site was transformed into one Lewis site. Low temperature nitrogen adsorption revealed that the treatment of highly siliceous zeolite with 0.2 M NaOH/TBAOH mixture produced mesopores of smaller diameter and narrower pore size distribution than in the case of zeolite of medium Si/Al ratio. This result can be explained by low concentration of Al which similarly as TBA + cations plays the role of pore directing agents (PDA). Contrary to TBA + , the presence of Al in desilication mixture, led to the formation of larger pores. Therefore, in highly siliceous zeolite TBA + played dominant role as PDA producing narrower pores. Highly siliceous zeolite with uniform distribution of relatively narrow pores may be useful catalyst or catalyst support. The influence of desilication temperature on porosity development was also investigated. The increase of desilication temperature from 338 K to 353 K resulted in both more extensive demetalation (more Si and Al is extracted) and the distinct increase of the volume and surface of mesopores. Both lower concentration of protonic sites and higher concentration of Lewis 2 sites confirmed partial zeolite destruction upon desilication at elevated temperature. The experiments of pivalonitrile sorption followed by IR spectroscopy showed a significant increase of accessibility of acid sites to bulky pivalonitrile molecules.

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Mesoporous beta zeolite obtained by desilication

Cited by 234 publications

References 42 publications

Catalytic cracking performance of alkaline-treated zeolite Beta in the terms of acid sites properties and their accessibility

Catalytic cracking performance of alkaline-treated zeolite Beta in the terms of acid sites properties and their accessibility

Influence of pore topology on synthesis and reactivity of Sn-modified zeolite catalysts for carbohydrate conversions

Desilication of highly siliceous zeolite ZSM-5 with NaOH and NaOH/tetrabutylamine hydroxide

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