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Diethyl Ether Conversion to Ethene and Ethanol Catalyzed by Heteropoly Acids
Rawan Al-Faze1,2, Elena F Kozhevnikova1, Ivan V Kozhevnikov1
1Department of Chemistry, University of Liverpool, Liverpool L69 7ZD, U.K.
ACS Omega
|April 12, 2021
Summary
Tungsten Keggin heteropoly acids efficiently convert diethyl ether (DEE) to ethene and ethanol at high temperatures. These solid acid catalysts show high activity and selectivity for ethene production.
Area of Science:
- Catalysis
- Materials Science
- Chemical Engineering
Background:
- Diethyl ether (DEE) conversion is crucial for producing valuable chemicals like ethene.
- Brønsted solid acid catalysts, particularly heteropoly acids (HPAs), are promising for gas-solid interface reactions.
- Understanding reaction mechanisms and catalyst performance is key to optimizing DEE conversion.
Purpose of the Study:
- To investigate the catalytic performance of bulk and supported tungsten Keggin heteropoly acids (HPAs) for DEE conversion.
- To determine the optimal reaction conditions for ethene and ethanol production.
- To elucidate the reaction mechanism and the role of acid sites in DEE elimination.
Main Methods:
- Gas-solid phase reaction studies using various HPA catalysts (bulk and silica-supported).
- Temperature range: 130-250 °C at ambient pressure.
- Analysis of product yields (ethene, ethanol) and correlation with catalyst properties (acid strength).
Main Results:
- High ethene yields (up to 98%) achieved at 220-250 °C.
- Silica-supported H₃PW₁₂O₄₀ and H₄SiW₁₂O₄₀, and bulk Cs₂.₅H₀.₅PW₁₂O₄₀ demonstrated superior activity compared to zeolites.
- A strong correlation between catalyst activity and acid strength confirmed the importance of Brønsted acid sites.
- Identified a consecutive reaction pathway: DEE → C₂H₄ + EtOH, followed by EtOH → C₂H₄ + H₂O.
Conclusions:
- Tungsten Keggin HPAs are highly effective catalysts for DEE conversion to ethene.
- Brønsted acid strength is a critical factor for catalyst performance in this reaction.
- The reaction proceeds via a surface-type mechanism over bulk and high-loaded HPA/SiO₂ catalysts.
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