3-6-3 流通式反応器とNi Sn/-TiO₂触媒を用いた酢酸水溶液の水素化によるバイオエタノール生産－副反応とその影響－

抄録

A novel bioethanol production process from lignocellulosics via acetic acid fermentation has been proposed in our laboratory. The hydrogenation reaction of acetic acid into ethanol was slowed down, when the reaction temperature reached 280-300°C in a flow-type reactor at 10 MPa. In the present paper, the slowdown mechanism was studied by investigating the reactivity of acetaldehyde as the intermediate. As a result, the Cannizzaro-type reaction, oxidation, and gasification were found to occur as the competitive side reactions along with the desired hydrogenation into ethanol. In addition all these three side-reactions were found to be catalyzed by this Ni-Sn/TiO₂ catalyst. The selectivities of these reactions at each temperature were determined, and the careful comparison with the data of acetic acid hydrogenation revealed that the oxidation of acetaldehyde into acetic acid that becomes significant at >300°C plays the most important role in the slow-down mechanism.