Hybrid mesoporous aluminosilicate catalysts obtained by non-hydrolytic sol-gel for ethanol dehydration
The result's identifiers
Result code in IS VaVaI
<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216224%3A14310%2F20%3A00114627" target="_blank" >RIV/00216224:14310/20:00114627 - isvavai.cz</a>
Result on the web
<a href="https://doi.org/10.1039/D0TA07016E" target="_blank" >https://doi.org/10.1039/D0TA07016E</a>
DOI - Digital Object Identifier
<a href="http://dx.doi.org/10.1039/d0ta07016e" target="_blank" >10.1039/d0ta07016e</a>
Alternative languages
Result language
angličtina
Original language name
Hybrid mesoporous aluminosilicate catalysts obtained by non-hydrolytic sol-gel for ethanol dehydration
Original language description
Ethanol dehydration is effectively catalyzed by solid acids, such as HZSM-5, alumina, or silica-alumina. In these catalysts, the amount, nature, and strength of acid sites is believed to determine catalyst activity and stability. However, surface hydrophilicity or hydrophobicity can be suggested as another decisive materials property that can directly influence performance. For example, a more hydrophobic surface might be beneficial in repelling the co-product of the reaction, water. However, these aspects have been studied only scarcely in the context of alcohol dehydration. Here, a series of mesoporous hybrid aluminosilicate materials containing CH3Si groups was prepared in one pot by non-hydrolytic sol-gel (NHSG). The presence of the methyl groups was verified by IR, solid-state NMR, and ToF-SIMS. Aluminum is mostly incorporated in tetrahedral coordination in the hybrid silica matrix. Two parameters were varied: (i) the aluminum loading (Si : Al ratio) and (ii) the degree of methylation (Si : MeSi ratio). On the one hand, changing the Si : Al ratio had a marked and expected impact on acidity. On the other hand, unexpectedly, the introduction of methyl groups had no clear influence on sample hydrophobicity. Nevertheless, some of the methylated aluminosilicate catalysts markedly outperformed the purely inorganic catalysts and a commercial silica-alumina benchmark. While a direct influence of surface hydrophilicity or hydrophobicity is unlikely, characterization of acidity (IR-pyridine) revealed that the improved performance for hybrid catalysts is correlated with a modification of the acidic properties (higher proportion of Lewis acid sites) caused by the introduction of methyl groups during the sol-gel process. A decisive role of acidity in ethanol dehydration was confirmed by an experiment with delayed addition of the Al precursor in the NHSG synthesis of the hybrid aluminosilicate. This led to a higher Al surface concentration, marked acid sites number increase, and better catalytic performance, even competing with the state of the art HZSM-5 in terms of ethylene yield.
Czech name
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Czech description
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Classification
Type
J<sub>imp</sub> - Article in a specialist periodical, which is included in the Web of Science database
CEP classification
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OECD FORD branch
10403 - Physical chemistry
Result continuities
Project
<a href="/en/project/GJ20-03636Y" target="_blank" >GJ20-03636Y: New Catalysts for Ethanol to 1,3-Butadiene Conversion</a><br>
Continuities
P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)
Others
Publication year
2020
Confidentiality
S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů
Data specific for result type
Name of the periodical
Journal of Materials Chemistry A
ISSN
2050-7488
e-ISSN
2050-7496
Volume of the periodical
8
Issue of the periodical within the volume
44
Country of publishing house
GB - UNITED KINGDOM
Number of pages
17
Pages from-to
23526-23542
UT code for WoS article
000590158400034
EID of the result in the Scopus database
2-s2.0-85096420424