Kinetic Modeling of Erythritol Deoxydehydration and Consecutive Hydrogenation over the ReO<sub><i>x</i></sub>-Pd/CeO<sub>2</sub> Catalyst
Ji Cao, Savitri Larasati, Mizuho Yabushita, Yoshinao Nakagawa, Johan Wärnå, Dmitry Yu. Murzin, Daiki Asada, Akira Nakayama, Keiichi Tomishige
Abstract
The reaction kinetics of deoxydehydration + hydrogenation (DODH + HG; didehydroxylation) of erythritol to butanediols and n -butane over the ReO x -Pd/CeO 2 catalyst was investigated. Competitive adsorption of polyols and catalyst deactivation during the DODH + HG reaction were necessary to be considered in the kinetics. The order of the adsorption strength on the catalyst surface was erythritol >1,2-butanediol > water >1,4-butanediol and monoalcohols. The deactivation during the reaction was investigated with two models: time-dependent and conversion-dependent ones. The conversion-dependent model better fitted both the activities of reused catalysts and the time-course data. The deactivated catalysts were characterized with TG-DTA and Raman spectroscopy. The weight loss and the temperature for the combustion of deposited organic species in TG-DTA did not correlate with the deactivation degree. On the other hand, a growing signal at around 910 cm –1 was observed in Raman spectroscopy in line with deactivation, which can be explained by the formation of aggregated ReO x species. The low activity of aggregated ReO x species was supported by DFT calculations showing that the activation energy of dimeric Re 2 O x H y /CeO 2 catalyst species for the cleavage of two C–O bonds is higher than that of monomeric ReO x H y /CeO 2 species.