Diethyl Ether Conversion to Ethene and Ethanol Catalyzed by Heteropoly Acids

Rawan Al-Faze; Elena F Kozhevnikova; Ivan V Kozhevnikov

doi:10.1021/acsomega.1c00958

Diethyl Ether Conversion to Ethene and Ethanol Catalyzed by Heteropoly Acids

ACS Omega. 2021 Mar 23;6(13):9310-9318. doi: 10.1021/acsomega.1c00958. eCollection 2021 Apr 6.

Authors

Rawan Al-Faze^{1

2}, Elena F Kozhevnikova¹, Ivan V Kozhevnikov¹

Affiliations

¹ Department of Chemistry, University of Liverpool, Liverpool L69 7ZD, U.K.
² Department of Chemistry, Taibah University, P.O. Box 30002, Al-Madinah Al-Munawarah 41147, Saudi Arabia.

Abstract

The conversion of diethyl ether (DEE) to ethene and ethanol was studied at a gas-solid interface over bulk and supported Brønsted solid acid catalysts based on tungsten Keggin heteropoly acids (HPAs) at 130-250 °C and ambient pressure. The yield of ethene increased with increasing reaction temperature and reached 98% at 220-250 °C (WHSV = 2.2 h^-1). The most active HPA catalysts were silica-supported H₃PW₁₂O₄₀ and H₄SiW₁₂O₄₀ and the bulk heteropoly salt Cs₂.₅H₀.₅PW₁₂O₄₀. The HPA catalysts outperformed zeolites HZSM-5 and USY reported elsewhere. A correlation between catalyst activity and catalyst acid strength was established, which indicates that Brønsted acid sites play an important role in DEE elimination over HPA catalysts. The results point to the reaction occurring through the consecutive reaction pathway: DEE → C₂H₄ + EtOH followed by EtOH → C₂H₄ + H₂O, where ethene is both a primary product of DEE elimination and a secondary product via dehydration of the primary product EtOH. Evidence is provided that DEE elimination over bulk HPA and high-loaded HPA/SiO₂ catalysts proceeds via the surface-type mechanism.