Desilication and silylation of Mo/HZSM-5 for methane dehydroaromatization

Tempelman, Chl Christiaan; Rodrigues, Victor de O.; Eck, van Ehr; Magusin, Pieter C. M. M.; Hensen, Emiel Emiel

doi:10.1016/j.micromeso.2014.10.020

Cited by 70 publications

(70 citation statements)

References 59 publications

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“…The decrease in acidity is due to exchange of the protons associated to the BAS with Mo-oxo species. Silylation led to further decrease of the acidity in agreement with an earlier report for Mo/ZSM-5 [73]. The acidity decrease in this case can be attributed to the improved spreading of Mo over the zeolite and to the deactivation of the external acid sites by the silylation treatment.…”

Section: Characterization Of Bifunctional Mo/zeolites Catalystssupporting

confidence: 91%

“…Several reports have discussed the formation of coke at the external surface BAS as the most likely reason for MDA catalyst deactivation [74][75][76][77]. Deactivation of these external surface BAS by the addition of a small amount of silica has been shown to improve benzene selectivity [73].…”

Section: Catalytic Activity Measurements: Methane Dehydroaromatizationmentioning

confidence: 99%

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One-pot synthesis of nano-crystalline MCM-22

Tempelman

Portilla

Martínez-Armero

et al. 2016

Microporous and Mesoporous Materials

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Nano-crystalline MCM-22 zeolite was synthesized in a one-pot procedure by the use of an organosilane (dimethyl-octadecyl-(3-trimethoxysilylpropyl)-ammonium chloride, TPOAC) in the zeolite synthesis gel. This crystal growth inhibition procedure introduced mesopores in the MCM-22 crystallites. The lower mechanical stability of the nano-crystalline MCM-22 zeolite compared with bulk MCM-22 can be countered to some extent by pillaring. The increased external surface of the microporous zeolite domains resulted in increased accessibility of the Brønsted acid sites, as followed from the better performance in liquidphase benzene alkylation with propylene as compared with bulk MCM-22. The increased accessibility of the internal acid sites in Mo-loaded hierarchical MCM-22 was also evident from the improved benzene selectivity during methane aromatization. Silylation of hierarchical Mo/MCM-22 was detrimental for the catalytic performance in MDA. The nano-crystalline MCM-22 has physico-chemical and catalytic properties intermediate between those of MCM-22 and ITQ-2 with the benefit over ITQ-2 that it can be synthesized in a single step.

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Section: Characterization Of Bifunctional Mo/zeolites Catalystssupporting

confidence: 91%

Section: Catalytic Activity Measurements: Methane Dehydroaromatizationmentioning

confidence: 99%

One-pot synthesis of nano-crystalline MCM-22

Tempelman

Portilla

Martínez-Armero

et al. 2016

Microporous and Mesoporous Materials

Self Cite

View full text Add to dashboard Cite

show abstract

“…Several studies have attempted to elucidate the reasons for the rapid deactivation of Mo/HZSM-5 catalysts during the MDA reaction [7][8][9][10][11][12][13][14][15][16][17]. Extensive formation of polyaromatics hydrocarbon carbon deposits was identified as the main reason for catalyst deactivation.…”

Section: Introductionmentioning

confidence: 99%

“…Some authors suggested that such carbon species may eventually block the micropore apertures [7,8]; this would explain the increased formation of ethylene at the expense of benzene [9]. Deactivation of the external surface BAS by silylation has been shown to decrease to some extent the formation rate of such unwanted carbon species, but catalyst deactivation cannot be completely prevented in this way [15][16][17]. Therefore, the coverage of the BAS inside the micropores by carbonaceous species is also considered to contribute to catalyst deactivation [10].…”

Section: Introductionmentioning

confidence: 99%