Characterization of Different Si- and Al-based Catalysts with Pd Modification and Their Use for Catalytic Dehydration of Ethanol

Abstract

This study aims to investigate the production of ethylene and diethyl ether from ethanol via catalytic dehydration using Si- and Al-based catalysts with Pd modification. First, six catalysts including H-beta zeolite (HBZ), mixed phases of γ-χ-Al₂O₃ (M-Al) and γ-Al₂O₃ (G-Al) with and without Pd modification (0.5 wt%) were prepared. The catalytic dehydration of vaporized ethanol at temperature ranging from 200 to 400°C was performed over the catalysts. For ethylene production, the most promising catalyst is HBZ (giving ethylene yield of ca. 99% at 400°C), whereas Pd modification has no significant effect on ethylene production. Considering the production of diethyl ether, it is produced at lower temperature (ca. 250°C) than that of ethylene. The most active catalyst to produce diethyl ether is HBZ with Pd modification (giving diethyl ether yield of ca. 48% at 250°C). Thus, increased diethyl ether yield can be achieved with Pd modification at low temperature for the HBZ catalyst. Other catalysts such as M-Al and G-Al can also produce significant amounts of ethylene. To elucidate the effect of Pd modification on these catalysts, different characterization techniques such as nitrogen physisorption (BET and BJH methods), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS) and ammonia temperature-programmed desorption were performed and further discussed in more detail.