Utilization of Ni as a Non-Noble-Metal Co-catalyst for Ceria-Supported Rhenium Oxide in Combination of Deoxydehydration and Hydrogenation of Vicinal Diols

Abstract

Removal of vicinal diols by combination of deoxydehydration and hydrogenation (DODH + HG) was carried out over the mixture of ReO x /CeO 2 and CeO 2 -supported base metals with H 2 as the reducing agent, in order to replace expensive Pd in the ReO x −Pd/CeO 2 catalyst used in previous studies for the same reaction. Similar high activity and selectivity of the mixture catalysts of ReO x /CeO 2 and pre-reduced Ni/CeO 2 were observed for DODH + HG as those of Pd-based catalysts (co-loaded ReO x −Pd/CeO 2 or mixture catalysts of ReO x /CeO 2 + Pd/CeO 2 ), while coloaded ReO x −Ni/CeO 2 catalyst showed almost no activity. The ReO x /CeO 2 + Ni/CeO 2 catalyst system gave 99% yield of tetrahydrofuran from 1,4anhydroerythritol and could be applied to DODH + HG of other diols and polyols such as glycerol, erythritol, and xylitol. Unlike ReO x −Pd/CeO 2 , the activity of the ReO x /CeO 2 + Ni/CeO 2 catalyst decreased in the reuse test, especially before second or later reuses, even when the recovered catalyst was calcined as regeneration. The catalysts were characterized by various methods such as thermal gravimetry−differential thermal analysis, temperatureprogrammed reduction with H 2 , and X-ray absorption fine structure spectroscopy. The deactivated ReO x /CeO 2 + Ni/CeO 2 catalyst after use and the inactive ReO x −Ni/CeO 2 catalyst after reduction had Re−Ni direct bonds, suggesting that the strong interaction between Re and Ni species decreased the activity of ReO x /CeO 2 in the DODH reaction.

Kinetic Modeling of Erythritol Deoxydehydration and Consecutive Hydrogenation over the ReOx-Pd/CeO2 Catalyst

“…When the erythritol conversion was below 80%, the selectivity to 1,2-butanediol and 1,4-butanediol was above 85% and below 15%, respectively, indicating that the DODH + HG of the primary-secondary vicinal OH groups in erythritol to form 1,2-butanediol proceeds more preferentially than that of the secondary-secondary vicinal OH groups to provide 1,4-butanediol. A similar 1,2-diol/1,4-diol ratio has been reported for ReO x /CeO 2 + Ni/CeO 2 mixture catalyst for DODH + HG and homogeneous Cp*ReO 3 catalyst for DODH . On the other hand, this 1,2-butanediol/1,4-butanediol ratio was smaller than the expected one from thermodynamics: Δ H f,liq difference is 16.1 kJ/mol, which corresponds to the equilibrium ratio of 110:1 at 413 K, with the assumption that the entropic term is negligible.…”

“…In the case of the ReO x -Pd/CeO 2 catalyst, the hydrogenation activity of Pd is very high, and the DODH products are readily hydrogenated to saturated ones (DODH + HG). The development of less expensive catalysts for DODH + HG has been recently carried out, such as ReO x /CeO 2 + Ni/CeO 2 and MoO x -Pd/TiO 2 ; however, the performance (activity or stability) is lower than that of ReO x -Pd/CeO 2 . Owing to the basic nature of the CeO 2 support, the ReO x -Pd/CeO 2 catalyst has almost no activity in acid-catalyzed reactions such as ether formation.…”

A perspective on catalytic production of olefinic compounds from biomass

“…There are several methods to synthesize propylene from biomass-derived compounds (Scheme 11). Propanols can be synthesized from glycerol relatively easily, by dehydration (to acrolein) + hydrogenation, 118,119 deoxydehydration (to allyl alcohol) + hydrogenation, [120][121][122] and metal-catalyzed hydrodeoxygenation. [123][124][125] Heterogeneous hydrodeoxygenation catalysts can adsorb polyols more strongly than mono-alcohols, and such preferential adsorption can suppress successive hydrodeoxygenation of propanols until complete consumption of glycerol and propanediols.…”

“…Other production methods of renewable tetrahydrofuran include furfural decarbonylation to furan followed by hydrogenation 173 and 1,4anhydroerythritol didehydroxylation (one-step deoxydehydration + hydrogenation). [120][121][122] Dehydration of tetrahydrofuran to butadiene is possible with strong acids but very difficult. The ring-opening of tetrahydrofurans involves carbocation intermediates; however, from tetrahydrofuran the intermediates are unstable primary carbocation species.…”

Highly Efficient Iridium–Iron–Molybdenum Catalysts Condensed on Boron Nitride for Biomass-Derived Diols’ Hydrogenolysis to Secondary Monoalcohols

“…Simultaneous removal of vicinal OH groups of 1,2-diols, for example, erythritol to 1,2-butanediol, was achieved over ReO x –Pd/CeO 2 catalyst in 2015, where the possible reaction route was proposed as a combination of deoxydehydration and hydrogenation . Recently, MoO x –Pd/TiO 2 and a mixture of ReO x /CeO 2 and Ni/CeO 2 catalysts were also reported as efficient catalysts with the same regioselectivity pattern as ReO x –Pd/CeO 2 . Primary C–O hydrogenolysis seems like a missing piece of united system of hydrodeoxygenation, where any corresponding alcohols can be selectively synthesized from biomass-derived platforms, for example, erythritol hydrogenolysis to C4 alcohols (Figure ).…”