Chlorine-Modified Ru/TiO₂ Catalyst for Selective Guaiacol Hydrodeoxygenation

Abstract

The selective hydrodeoxygenation of lignin-derived guaiacol to value-added products, especially phenol, under relatively mild reaction conditions remains an important challenge. A Cl-modified Ru/TiO 2 catalyst exhibited higher phenol selectivity compared with an unmodified one in the conversion of guaiacol in 1,4-dioxane at 240 °C and 1 MPa H 2 . Unlike Ru/TiO 2 , the modified catalyst exhibited a modest activity of demethoxylation producing phenol but an inferior ability of hydrogenation of its aromatic ring, resulting in much slower consumption of phenol. The Cl species were likely localized at the metal−support interface and on the surface of metal particles, and these modified both Ru and Ti species electronically. It is presumed that electron-enriched Ru inhibits the ring hydrogenation reaction, and the defects on the TiO 2 surface promote the deoxygenation reaction.

Influence of Brønsted acid sites on the product distribution in the hydrodeoxygenation of methyl laurate over supported Ru catalysts

“…As reported in the literature, the binding energies of Ru 0 are located at 279.5-280.9 eV and those of Ru n+ are at 281.0-282 eV. 31,32 It is worth noting that as the Brønsted acid sites increased, the binding energy of Ru 0 gradually shifted to a higher value, indicating the Ru species on the surface became more electron-deficient (Fig. S4 †).…”

Higher loadings of Pt single atoms and clusters over reducible metal oxides: application to C–O bond activation

“…They interact strongly with unsaturated rings to induce hydrogenolysis and hydrogenation of unsaturated CC and CO bonds. [5][6][7] Our group has found that the redox sites of reducible metal oxides enable HDO reactions of the side groups of furans without ring-hydrogenation and ringopening. 8 The rate depends on the catalyst's ability to form oxygen vacancies while remaining stable under reaction conditions.…”

Selective Demethoxylation of Guaiacols to Phenols using Supported MoO3 Catalysts

“…[14,15] Several exploratory catalyst studies for the selective conversion of guaiacol to demethoxylated phenolics have been reported in the literature. Examples are precious metal catalysts like PtÀ Sn/CNF/Inconel, [16] Pd/C, [17] TiO 2 supported Au, Ag, and Ru catalysts [18][19][20][21][22] but also cheaper Fe-based catalysts such as FeO x /CeO 2 , [23] supported Ni catalysts, [24,25] and Mo oxide catalysts [14,[26][27][28][29][30] , as shown in Table 1. Both batch set-up and fixed-bed reactors were used in previous studies.…”