Diethyl Ether Conversion to Ethene and Ethanol Catalyzed by Heteropoly Acids

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 H 3 PW 12 O 40 and H 4 SiW 12 O 40 and the bulk heteropoly salt Cs 2 . 5 H 0 . 5 PW 12 O 40 . 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 → C 2 H 4 + EtOH followed by EtOH → C 2 H 4 + H 2 O, 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/SiO 2 catalysts proceeds via the surface-type mechanism.

A General Strategy for Efficient Upgrading of Biomass-Derived Rice Husk Vinegar with ZrO2 Supported HSiW Catalyst: Extractive Coupling Esterification

“…It was discovered that the catalyst's surface area decreased by a factor of 5 as the loading capacity increased from 10% to 75%, while the pore size remained relatively unchanged. 36 This finding aligns with our analysis, indicating that HSiW coated the surface of ZrO 2 without infiltrating the internal pore structure. Consequently, the surface area and pore structure did not serve as the primary factors influencing the catalytic activity.…”

“…The Keggin-type heteropolyacid (HPA) represented a pure Brønsted acid, whereas ZrO 2 demonstrated Lewis acid properties attributed to the presence of Zr 4+ ions on its surface. 36 As the HPAs loading increased, a notable enhancement in the number of Brønsted acid sites on the HPAs/ZrO 2 catalyst was observed. 35 Therefore, strong and weak acids were considered to represent Brønsted and Lewis acids, respectively, in this study.…”

Phosphomolybdic acid hydrate encapsulated in MIL-53 (Fe): a novel heterogeneous heteropoly acid catalyst for ultrasound-assisted regioselective nitration of phenols

“…[69][70][71][72] Therefore, researchers have focused on the synthesis of heterogenized heteropoly acids. [73][74][75] Accordingly, we would introduce a novel phosphomolybdic acid hydrate (PMA) encapsulated @MIL-53 (Fe) MOF using the co-synthesis method as a novel functionalized MOF catalyst.…”

Combining Theoretical and Experimental Methods to Probe Confinement within Microporous Solid Acid Catalysts for Alcohol Dehydration

“…The ethanol conversion for SAPO-34 remains constant, despite changes in operating parameters, suggesting that this is not a kinetic effect. Recent works suggest that this could be due to our conditions, where SAPO-34 only is approaching equilibrium conversion for ethanol dehydration, 113 and agree with our findings that lower temperature favors diethyl ether formation, before this subsequently forms ethene, and this may also be due to nonoptimized reactor design or catalyst packing within the fixed bed. 114 In our previous works, the activation energies of three possible reaction steps were found to be between 66 and 143 kJ/mol, under similar conditions, as those employed here.…”