Tandem Hydrogenation/Hydrogenolysis of Furfural to 2-Methylfuran over a Fe/Mg/O Catalyst: Structure–Activity Relationship (original) (raw)
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ChemSusChem, 2016
Iron-based heterogeneous catalysts, which were generally prepared by pyrolysis of iron complexes on supports at elevated temperature, were found to be capable of catalyzing the transfer hydrogenation of furfural (FF) to furfuryl alcohol (FFA). The effects of metal precursor, nitrogen precursor, pyrolysis temperature, and support on catalytic performance were examined thoroughly, and a comprehensive study of the reaction parameters was also performed. The highest selectivity of FFA reached 83.0 % with a FF conversion of 91.6 % under the optimal reaction condition. Catalyst characterization suggested that iron cations coordinated by pyridinic nitrogen functionalities were responsible for the enhanced catalytic activity. The iron catalyst could be recycled without significant loss of catalytic activity for five runs, and the destruction of the nitrogen-iron species, the presence of crystallized Fe2 O3 phase, and the pore structure change were the main reasons for catalyst deactivation.
Selective conversion of furfural to methylfuran over silica-supported NiFe bimetallic catalysts
Journal of Catalysis, 2011
The conversion of furfural in H 2 over SiO 2 -supported Ni and NiAFe bimetallic catalysts has been investigated at 1 bar in the 210-250°C temperature range. Over the monometallic Ni catalyst, furfuryl alcohol and furan are primary products resulting from hydrogenation and decarbonylation, respectively. These primary products are further converted in secondary reactions. Furan yields C 4 products (butanal, butanol, and butane) via ring opening, while furfuryl alcohol produces 2-methylfuran via CAO hydrogenolysis. By contrast, 2-methylfuran is not produced to a great extent on pure Ni at any level of overall conversion. But, on FeANi bimetallic catalysts, the yield of 2-methylfuran greatly increases while the yields of furan and C 4 products decrease. That is, the addition of Fe suppresses the decarbonylation activity of Ni while promoting the C@O hydrogenation (at low temperatures) and the CAO hydrogenolysis (at high temperatures). DFT analysis of the possible surface species on the mono-and bimetallic surfaces suggests that the differences in selectivity displayed by these catalysts can be attributed to the stability of the g 2 -(C,O) surface species, which is higher on the NiAFe than on pure Ni. As a result, this g 2 -(C,O) species can be readily hydrogenated to furfuryl alcohol and subsequently hydrogenolyzed to 2-methylfuran on the bimetallic alloy due to a strong interaction between the carbonyl O and the oxyphilic Fe atoms. Without Fe, on the pure Ni surface, the g 2 -(C,O) species can be converted into a surface acyl species, which can be decomposed to produce furan and CO. Detailed XRD and TPR characterization indicate the formation of FeANi alloys in all the bimetallic catalysts.
The liquid phase catalytic hydrogenation of furfural to furfuryl alcohol
Catalysis Today, 2018
The results of the study of palladium catalysts in the selective hydrogenation of furfural to furfural alcohol are presented. A comparison of the properties of palladium catalytic systems prepared on different supports (aluminium oxide, hypercrosslinked polystyrene and magnetite/hypercrosslinked polystyrene) is carried out. It is shown that the nature of the support has a significant impact on both the morphology of the catalyst and its activity in the selective hydrogenation of furfural. The most effective catalyst was magnetically recoverable 3 % Pd/Fe3O4/HPS, in the presence of which the conversion of furfural was> 95% with selectivity for furfuryl alcohol> 94 %.
ACS Catalysis
Biomass conversion to fuels and chemicals provides sustainability, but the highly oxygenated nature of a large fraction of biomass-derived molecules requires removal of the excess oxygen and partial hydrogenation in the upgrade, typically met by hydrodeoxygenation processes. Catalytic transfer hydrogenation is a general approach in accomplishing this with renewable organic hydrogen donors, but mechanistic understanding is currently lacking. Here, we elucidate the molecular level reaction pathway of converting hemicellulose-derived furfural to 2-methylfuran on a bifunctional Ru/RuO x /C catalyst using isopropyl alcohol as the hydrogen donor via a combination of isotopic labeling and kinetic studies. Hydrogenation of the carbonyl group of furfural to furfuryl alcohol proceeds through a Lewis acid-mediated intermolecular hydride transfer and hydrogenolysis of furfuryl alcohol occurs mainly via ring-activation involving both metal and Lewis acid sites. Our results show that the bifunctional nature of the catalyst is critical in the efficient hydrodeoxygenation of furanics and provides insights toward the rational design of such catalysts.
Molecules, 2021
Heterogeneous catalysis, which has served well the petrochemical industry, may valuably contribute towards a bio-based economy by sustainably enabling selective reactions to renewable chemicals. Carbohydrate-containing matter may be obtained from various widespread sources and selectively converted to furanic platform chemicals: furfural (Fur) and 5-(hydroxymethyl)furfural (Hmf). Valuable bioproducts may be obtained from these aldehydes via catalytic transfer hydrogenation (CTH) using alcohols as H-donors under relatively moderate reaction conditions. Hafnium-containing TUD-1 type catalysts were the first of ordered mesoporous silicates explored for the conversion of Fur and Hmf via CTH/alcohol strategies. The materials promoted CTH and acid reactions leading to the furanic ethers. The bioproducts spectrum was broader for the reaction of Fur than of Hmf. A Fur reaction mechanism based on literature data was discussed and supported by kinetic modelling. The influence of the Hf loadin...
Catalysts, 2015
The one-pot catalytic reductive etherification of furfural to 2-methoxymethylfuran (furfuryl methyl ether, FME), a valuable bio-based chemical or fuel, is reported. A large number of commercially available hydrogenation heterogeneous catalysts based on nickel, copper, cobalt, iridium, palladium and platinum catalysts on various support were evaluated by a high-throughput screening approach. The reaction was carried out in liquid phase with a 10% w/w furfural in methanol solution at 50 bar of hydrogen. Among all the samples tested, carbon-supported noble metal catalysts were found to be the most promising in terms of productivity and selectivity. In particular, palladium on charcoal catalysts show high selectivity (up to 77%) to FME. Significant amounts of furfuryl alcohol (FA) and 2-methylfuran (2-MF) are observed as the major by-products.
Journal of the Brazilian Chemical Society, 2020
This work presents the results obtained for the gas chromatography-mass spectrometry (GC-MS) monitoring of the liquid-phase hydrodeoxygenation (HDO) reaction of furfural (FFR) to 2-methylfuran (MF) over a bifunctional Ru/RuO x /C catalyst in the presence of a direct source of H 2. Hydrogenation and hydrogenolysis reactions of FFR and of the intermediate furfuryl alcohol (FA), respectively, were independently studied to provide insights on the HDO mechanism. The mass spectra monitoring of the kinetic isotope effect indicated the HDO reaction occurs through a twostep mechanism comprising of an initial ruthenium-mediated hydrogenation reaction of FFR to FA. In the second step, the FA thus formed experiences a hydrogenolysis reaction via ring activation where the hydrogen atoms are firstly attached to the C3 carbon generating a ring activated structure and removing the OH group. The observation of the peaks at m/z 85 and 84 in the mass spectrum of the MF product confirms this reaction pathway.