Ethylene chain growth in catalytic dehydration of Bio-ethanol using various groups of metal catalysts

Abstract

Metal catalysts that have been widely used to produce aliphatic long-chain hydrocarbons were selected based on two group of reactions; that are Fischer-Tropsch synthesis (FT) and Olefin polymerization (OPR) for the catalytic dehydration of bio-ethanol. Moreover, γ-AI2O3 has been found as the simple, but suitable support for ethylene production in ethanol dehydration because of its acidity and physical property, Therefore, the effect of metal-promoted catalysts were examined in the catalytic dehydration of bioethanol, aiming to investigate the possibility of ethylene oligomerization and chain growth form the product. The change of oxidation state of metals was also investigated for its effect on bio-ethanol dehydration products. As a result, all metal-promoted catalysts tended to have possibility to promote ethylene oligomerization, but they had different ability. Fischer-Tropsch-type catalysts; that are, Co and Fe catalysts, promoted similar pathways of ethylene chain growth through ethylene aromatization. Consequently, the hydrocarbon products were all aromatics. On the other hand, the growth of ethylene by using olefin polymerization-type catalysts can be divided into two different pathways. Ni, Cu, and Pd catalysts tend to promote ethylene chain growth via cyclization and dehydrogenation. However, Cr catalysts seem to promote the growth of ethylene through oligomerization, cyclization, and dehydrogenation. In addition, the hydrocarbons obtained from using FT-type catalysts were all aromatics. However, the hydrocarbons obtained from using the OPR-type catalysts were composed of non-aromatics and aromatics.