Synergistic effect of highly dispersed Ru and moderate acid site on the hydrodeoxygenation of phenolic compounds and raw bio-oil

Competitive Hydrogenation and Hydrodeoxygenation of Oxygen-Substituted Aromatics over Rh/Silica: Catechol, Resorcinol and Hydroquinone

“…These comparisons suggest that the presence of the second reactant has no significant effect on the HDO reaction and that the only effect of the second component is to reduce the rate of hydrogenation. This is in keeping with the literature where the hydrogenation functionality was significantly reduced in a competitive environment [14,15].…”

“…This was surprising because individually resorcinol had displayed an iKIE [6]. The change to a normal KIE for resorcinol implies a significant change in surface energetics for resorcinol ring hydrogenation, which is consistent with hydrogenation being affected by the presence of a second reactant [14,15]. The iKIE was explained by the change from sp 2 hybridized carbon to sp 3 hydridized carbon being the rate determining step [16], however the normal KIE suggests that hydrogen bond breaking or making is involved in the rate determining step.…”

“…To enable this, we must understand how reactions in a competitive environment affect each other. In recent studies of bio-oil HDO [14,15] it was found that although the HDO reaction was still effective, there was a significant change in behaviour relative to single model compounds.…”

“…For example, with guaiacol as a single reactant the products were, with most catalysts, cyclohexane derivatives, whereas for guaiacol in bio-oil HDO the product was mostly aromatic in nature. Indeed, in general the hydrogenation functionality was significantly reduced in a competitive environment [14,15]. Therefore, having already thoroughly studied the single hydrogenation/HDO of the dihydroxybenzene isomers [6] we undertook to examine the competitive reactions in pairs and with all three isomers using hydrogen and deuterium to aid mechanistic understanding.…”

Dynamics of carbon formation during the catalytic hydrodeoxygenation of raw bio-oil

“…31 This difference is explained by the higher capacity of noble metal-based catalysts for C-O bond cleavage and demethoxylation of alkyl(methoxy)phenols, hence leading to a heavily hydrogenated end liquid product. 39,40 All in all, when bio-oil HDO is intended for the production of certain platform chemicals, the pore blockage and masking of acidic sites caused by coke deposits results benecial in order to limit the hydrogenation capability of the catalyst, resulting in higher yields of unsaturated compounds. The acidic and structural properties of the used catalysts are reported in Table S1.…”