Deoxydehydration of Biomass‐Derived Polyols Over Silver‐Modified Ceria‐Supported Rhenium Catalyst with Molecular Hydrogen

Abstract

Olefin production from polyols via deoxydehydration (DODH) was carried out over Ag-modified CeO 2 -supported heterogeneous Re catalysts with H 2 as a reducing agent. Both high DODH activity and low hydrogenation ability for C=C bonds were observed in the reaction of erythritol, giving a 1,3butadiene yield of up to 90 % under "solvent-free" conditions. This catalyst is applicable to other substrates such as methyl glycosides (methyl α-fucopyranoside: 91 % yield of DODH product; methyl β-ribofuranoside: 88 % yield), which were difficult to be converted to the DODH products over the DODH catalysts reported previously. ReO x -Ag/CeO 2 was reused 3 times without a decrease of activity or selectivity after calcination as regeneration. Although the transmission electron microscopy energy-dispersive X-ray spectroscopy and X-ray absorption fine structure analyses showed that Re species were highly dispersed and Ag was present as metal particles with various sizes from well-dispersed species (< 1 nm) to around 5 nm particles, the catalysts prepared from size-controlled Ag nanoparticles showed similar performance, indicating that the catalytic performance is insensitive to the Ag particle size.

Hydrodeoxygenation of potential platform chemicals derived from biomass to fuels and chemicals

“…144,145 ReO x -Ag/CeO 2 catalyzed the DODH of 1,4-AHERY with H 2 to produce 2,5-dihydrofuran in high yield (∼88%) with 5% yield of 2,3-dihydrofuran. 147 It was also reported recently that MoO x -Au/ TiO 2 and MoO x -Pd/TiO 2 emerged as good catalysts for the DODH of 1,4-AHERY with H 2 to form 2,5-dihydrofuran (77% yield) 148 and tetrahydrofuran, 148,244 respectively. Although high selectivity was reported, the activity of the MoO x -M/TiO 2 -catalyzed system was significantly lower than that of the ReO x -M/ CeO 2 -catalyzed systems (higher reaction temperature or lower initial reaction rate), because of the intrinsic lower activity of Mo species in DODH than that of Re.…”

“…In the case of Au-and Ag-added catalysts, DODH products (alkenes) become major products since the consecutive hydrogenation of CvC in DODH products does not proceed over Au [144][145][146] or Ag. 147 In contrast, ReO x -Pd/CeO 2 catalysts, in which Pd species have the same role as Au and Ag to reduce Re, gave the saturated products through the high hydrogenation activity of Pd. [151][152][153][154] This reaction system is called "DODH + hydrogenation", and the reaction scheme is shown in Fig.…”

“…In contrast, the DODH of alkyl glycosides with cis-vicinal OH groups is possible. In particular, the combination of ReO x -M/CeO 2 (M = Pd, Ag, and Au) catalysts with H 2 reductant enhances the DODH activity and decreases the reaction temperature, which allows the application of ReO x -M/CeO 2 (M = Pd, 156,157 Ag, 147 and Au 146 ) to the DODH of methyl glycosides with cis-vicinal OH groups.…”

“…144,145 It has been recently reported that ReO x -Ag/ CeO 2 exhibited a higher activity than ReO x -Au/CeO 2 and a comparably high yield of 1,3-butadiene. 147 Furthermore, the application of "solventless" conditions further increased the yield of 1,3-butadiene, probably due to the efficient transfer of 1,3-butadiene from the liquid phase (erythritol and butenediols for the "solventless" conditions) to the gas phase. In addition, the "solventless" conditions greatly improved the E-factor.…”

“…DODH (+hydrogenation) of methyl glycosides with cis-vicinal OH groups using ReO x -M/CeO 2 catalysts and H 2 reductant147,152,156 …”