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Dionisios G Vlachos - One of the best experts on this subject based on the ideXlab platform.
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mechanistic insights into metal lewis acid mediated catalytic transfer hydrogenation of Furfural to 2 methylfuran
ACS Catalysis, 2015Co-Authors: Matthew J Gilkey, Paraskevi Panagiotopoulou, Alexander V Mironenko, Glen R Jenness, Dionisios G VlachosAbstract: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/RuOx/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 cataly...
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coverage induced conformational effects on activity and selectivity hydrogenation and decarbonylation of Furfural on pd 111
ACS Catalysis, 2015Co-Authors: Shengguang Wang, Vassili Vorotnikov, Dionisios G VlachosAbstract:Adsorption, hydrogenation, and decarbonylation of Furfural on hydrogen-covered Pd(111) was investigated using density functional theory calculations. It was found that both the energy and the conformation of adsorbed Furfural vary with increasing coverage of hydrogen or Furfural. Furfural lies flat at low coverage but becomes tilted on crowded surfaces. The energy profiles of hydrogenation and decarbonylation reactions on a hydrogen-covered Pd(111) change profoundly compared to those on bare Pd(111). The energy span theory shows that the Furfural hydrogenation and decarbonylation effective barriers exhibit a maximum with increasing hydrogen coverage. In contrast, the selectivity to hydrogenation toward furfuryl alcohol over decarbonylation is favored with increasing hydrogen coverage. Microkinetic modeling suggests that the conformation change with increasing H coverage has a significant effect on reaction rates (up to orders of magnitude) and induces a selectivity reversal from furan as the main product ...
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effect of hydrogen donor on liquid phase catalytic transfer hydrogenation of Furfural over a ru ruo2 c catalyst
Journal of Molecular Catalysis A-chemical, 2014Co-Authors: Paraskevi Panagiotopoulou, Nickolas Martin, Dionisios G VlachosAbstract:Abstract The effect of alcohol hydrogen donor on methyl furan production through catalytic transfer hydrogenation of Furfural in the liquid phase has been investigated over a mildly calcined Ru/C catalyst in the temperature range of 110–200 °C. It has been found that several parameters contribute to Furfural hydrogenolysis, including alcohol dehydrogenation activity, solvent properties, as well as side reactions such as etherification between the intermediate, furfuryl alcohol, and the hydrogen donor. Methyl furan yield increases from 0 to 68% at 180 °C following the order of 2-methyl-2-butanol
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liquid phase catalytic transfer hydrogenation of Furfural over a ru c catalyst
Applied Catalysis A-general, 2014Co-Authors: Paraskevi Panagiotopoulou, Dionisios G VlachosAbstract:Abstract Methyl furan production through catalytic transfer hydrogenation of Furfural in the liquid phase has been investigated over a Ru/C catalyst in the temperature range of 120–200 °C using 2-propanol as a solvent. It has been found that Furfural hydrogenation produces furfuryl alcohol, which undergoes hydrogenolysis to methyl furan. Small amounts of furan and traces of tetrahydrofurfuryl alcohol are also produced via Furfural decarbonylation and furfuryl alcohol ring hydrogenation, respectively. Furfuryl alcohol can dimerize or produce ether with 2-propanol. The yield of methyl furan is enhanced with increasing reaction temperature and/or reaction time. Optimum results are attained after 10 h of reaction at 180 °C, where Furfural conversion and methyl furan yield reach 95% and 61%, respectively, which is the highest reported yield in the liquid phase at temperatures lower than 200 °C. The reaction network has been investigated by analysing the evolution of reaction intermediates and products and by starting from furfuryl alcohol, methyl furan, and furan hydrogenation. Intermediates, as well as methyl furan, are produced faster when starting with furfuryl alcohol as the reactant, rather than Furfural, indicating that initial hydrogenation of Furfural to furfuryl alcohol is slow. Catalyst recycling experiments over spent Ru/C catalyst show that, although Furfural conversion does not decrease significantly, furfuryl alcohol yield increases at the expense of methyl furan. The initial catalytic activity and selectivity are regained completely after catalyst regeneration. We show evidence that the active phase of the catalyst involves Ru and RuO x .
Keiichi Tomishige - One of the best experts on this subject based on the ideXlab platform.
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total hydrogenation of Furfural and 5 hydroxymethylFurfural over supported pd ir alloy catalyst
ACS Catalysis, 2014Co-Authors: Yoshinao Nakagawa, Kana Takada, Masazumi Tamura, Keiichi TomishigeAbstract:Hydrogenation of aqueous Furfural was conducted with SiO2-suported palladium-based bimetallic catalysts. The combination of palladium and iridium gave the best performance for the total hydrogenation to tetrahydrofurfuryl alcohol. Higher H2 pressure and lower reaction temperature were advantageous to suppress side reactions. The synergy between Pd and Ir in the hydrogenation catalysis is most remarkable for substituted furans as substrates. Furfural was first converted into furfuryl alcohol, which was further converted to tetrahydrofurfuryl alcohol. A small amount of tetrahydroFurfural was formed in the first step (∼20% selectivity), and the subsequent hydrogenation of tetrahydroFurfural was much slower. The combined yield of tetrahydrofurfuryl alcohol and tetrahydroFurfural reached 98%. The yield of tetrahydrofurfuryl alcohol reached 94% with larger amount of catalyst. Total hydrogenation of 5-hydroxymethylFurfural was also possible using Pd–Ir/SiO2 catalyst. The performance of Pd–Ir/SiO2 catalyst was sl...
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catalytic reduction of biomass derived furanic compounds with hydrogen
ACS Catalysis, 2013Co-Authors: Yoshinao Nakagawa, Masazumi Tamura, Keiichi TomishigeAbstract:Furfural and 5-hydroxymethylFurfural (HMF) are important platform chemicals in biorefinery. Reduction of Furfural or HMF with H2 over heterogeneous catalysts is the simplest way to convert the oxygen-rich compounds. However, the process can involve many types of reactions such as hydrogenation of the C═O bond, hydrogenation of the furan ring, C–O hydrogenolysis, rearrangement, C–C dissociation, and polymerization. Hydrogenation reactions are most studied in line with hydrogenations of other α,β-unsaturated aldehydes, and it becomes possible to produce each product selectively: furfuryl alcohol, tetrahydrofurfuryl alcohol, 2,5-bis(hydroxymethyl)furan, or 2,5-bis(hydroxymethyl)tetrahydrofuran. Total reduction of side substituents to give 2-methylfuran or 2,5-dimethylfuran is another well-known reaction. Rearrangement and C–O hydrogenolysis reactions have been recently investigated, and they can give useful products such as cyclopentanone, 1,5-pentanediol, and 1,6-hexanediol. Ongoing studies of the reaction ...
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total hydrogenation of Furfural over a silica supported nickel catalyst prepared by the reduction of a nickel nitrate precursor
Chemcatchem, 2012Co-Authors: Yoshinao Nakagawa, Hiroya Nakazawa, Hideo Watanabe, Keiichi TomishigeAbstract:Gas-phase hydrogenation of Furfural to tetrahydrofurfuryl alcohol is catalyzed by Ni/SiO2 with <4 nm Ni particle size, which is prepared by the reduction of supported nickel nitrate. The maximum yield is 94 %. The conversion of Furfural to the furfuryl alcohol intermediate is less structure-sensitive. The subsequent step in which furfuryl alcohol is converted to tetrahydrofurfuryl alcohol is inhibited by the presence of Furfural because Furfural is more strongly adsorbed onto the catalyst surface than furfuryl alcohol. This step is strongly structure-sensitive and smaller turnover frequency (TOF) values are observed over Ni/SiO2 catalysts with a larger particle size.
Daniel E Resasco - One of the best experts on this subject based on the ideXlab platform.
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selective conversion of Furfural to methylfuran over silica supported nife bimetallic catalysts
Journal of Catalysis, 2011Co-Authors: Surapas Sitthisa, Daniel E ResascoAbstract:Abstract The conversion of Furfural in H 2 over SiO 2 -supported Ni and Ni Fe 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 C O hydrogenolysis. By contrast, 2-methylfuran is not produced to a great extent on pure Ni at any level of overall conversion. But, on Fe Ni 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 C O 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 η 2 -(C,O) surface species, which is higher on the Ni Fe than on pure Ni. As a result, this η 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 η 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 Fe Ni alloys in all the bimetallic catalysts.
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hydrodeoxygenation of Furfural over supported metal catalysts a comparative study of cu pd and ni
Catalysis Letters, 2011Co-Authors: Surapas Sitthisa, Daniel E ResascoAbstract:The hydrodeoxygenation of Furfural has been investigated over three different metal catalysts, Cu, Pd and Ni supported on SiO2, on a continuous-flow reactor under atmospheric pressure of hydrogen in the 210–290 °C temperature range. The distribution of products is a strong function of the metal catalyst used. High selectivity to furfuryl alcohol is obtained over Cu/SiO2, with the formation of only small amounts of 2-methyl furan at the highest reaction temperature studied. In contrast to Cu catalyst, the conversion of Furfural over Pd/SiO2 mainly produces furan by decarbonylation. Furan can further react with hydrogen to form tetrahydrofuran (THF). Finally, on Ni/SiO2 catalysts ring opening products (butanal, butanol and butane) can be obtained in significant amounts. The different product distributions are explained in terms of the strength of interaction of the furan ring with the metal surface and the type of surface intermediates that each metal is able to stabilize.
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kinetics and mechanism of hydrogenation of Furfural on cu sio2 catalysts
Journal of Catalysis, 2011Co-Authors: Surapas Sitthisa, Tawan Sooknoi, Perla B Balbuena, Daniel E ResascoAbstract:Abstract The hydrogenation/hydrodeoxygenation of Furfural was studied on a Cu/SiO 2 catalyst at 230–290 °C. Detailed kinetics, density function (DFT) calculations, and spectroscopic studies were combined to investigate this reaction. A Langmuir–Hinshelwood model was found to fit the kinetic data well and provided the parameters of physical significance. The heat of adsorption (Δ H ads ) of Furfural, derived from the fitting, was found to be significantly higher than those of furfuryl alcohol and 2-methyl furan. Activation energies for the conversion of Furfural and furfuryl alcohol were both about 12 kcal/mol. DFT calculations and DRIFTS provided guidance about the nature of the surface species. Accordingly, the most likely species adsorbed on the Cu surface is suggested to be a top η 1 (O)-aldehyde. DFT calculations of the reaction path show that the predicted energy barriers are of the same order as the experimental values and suggest that the hydrogenation of Furfural can occur via either an alkoxide or ahydroxyalkyl intermediate.
Yoshinao Nakagawa - One of the best experts on this subject based on the ideXlab platform.
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total hydrogenation of Furfural and 5 hydroxymethylFurfural over supported pd ir alloy catalyst
ACS Catalysis, 2014Co-Authors: Yoshinao Nakagawa, Kana Takada, Masazumi Tamura, Keiichi TomishigeAbstract:Hydrogenation of aqueous Furfural was conducted with SiO2-suported palladium-based bimetallic catalysts. The combination of palladium and iridium gave the best performance for the total hydrogenation to tetrahydrofurfuryl alcohol. Higher H2 pressure and lower reaction temperature were advantageous to suppress side reactions. The synergy between Pd and Ir in the hydrogenation catalysis is most remarkable for substituted furans as substrates. Furfural was first converted into furfuryl alcohol, which was further converted to tetrahydrofurfuryl alcohol. A small amount of tetrahydroFurfural was formed in the first step (∼20% selectivity), and the subsequent hydrogenation of tetrahydroFurfural was much slower. The combined yield of tetrahydrofurfuryl alcohol and tetrahydroFurfural reached 98%. The yield of tetrahydrofurfuryl alcohol reached 94% with larger amount of catalyst. Total hydrogenation of 5-hydroxymethylFurfural was also possible using Pd–Ir/SiO2 catalyst. The performance of Pd–Ir/SiO2 catalyst was sl...
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catalytic reduction of biomass derived furanic compounds with hydrogen
ACS Catalysis, 2013Co-Authors: Yoshinao Nakagawa, Masazumi Tamura, Keiichi TomishigeAbstract:Furfural and 5-hydroxymethylFurfural (HMF) are important platform chemicals in biorefinery. Reduction of Furfural or HMF with H2 over heterogeneous catalysts is the simplest way to convert the oxygen-rich compounds. However, the process can involve many types of reactions such as hydrogenation of the C═O bond, hydrogenation of the furan ring, C–O hydrogenolysis, rearrangement, C–C dissociation, and polymerization. Hydrogenation reactions are most studied in line with hydrogenations of other α,β-unsaturated aldehydes, and it becomes possible to produce each product selectively: furfuryl alcohol, tetrahydrofurfuryl alcohol, 2,5-bis(hydroxymethyl)furan, or 2,5-bis(hydroxymethyl)tetrahydrofuran. Total reduction of side substituents to give 2-methylfuran or 2,5-dimethylfuran is another well-known reaction. Rearrangement and C–O hydrogenolysis reactions have been recently investigated, and they can give useful products such as cyclopentanone, 1,5-pentanediol, and 1,6-hexanediol. Ongoing studies of the reaction ...
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total hydrogenation of Furfural over a silica supported nickel catalyst prepared by the reduction of a nickel nitrate precursor
Chemcatchem, 2012Co-Authors: Yoshinao Nakagawa, Hiroya Nakazawa, Hideo Watanabe, Keiichi TomishigeAbstract:Gas-phase hydrogenation of Furfural to tetrahydrofurfuryl alcohol is catalyzed by Ni/SiO2 with <4 nm Ni particle size, which is prepared by the reduction of supported nickel nitrate. The maximum yield is 94 %. The conversion of Furfural to the furfuryl alcohol intermediate is less structure-sensitive. The subsequent step in which furfuryl alcohol is converted to tetrahydrofurfuryl alcohol is inhibited by the presence of Furfural because Furfural is more strongly adsorbed onto the catalyst surface than furfuryl alcohol. This step is strongly structure-sensitive and smaller turnover frequency (TOF) values are observed over Ni/SiO2 catalysts with a larger particle size.
Milan Hronec - One of the best experts on this subject based on the ideXlab platform.
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A facile conversion of Furfural to novel tetrahydrofurfuryl hemiacetals
Applied Catalysis A: General, 2020Co-Authors: Milan Hronec, Katarína Fulajtárová, Blažej Horváth, Tibor Liptaj, Edmund DobročkaAbstract:Abstract An entirely new and highly selective method for preparation of novel tetrahydrofurfuryl hemiacetals is described. The process is based on the catalytic hydrogenation of Furfural in an alcohol under mild reaction conditions and at very short reaction times. As a highly active and selective catalyst palladium supported on calcium carbonate is used. Basic sites of the catalyst support enhance the formation of furfuryl hemiacetal as the intermediate which is instantaneously hydrogenated into stable tetrahydrofurfuryl hemiacetal. About 85–90 % yields of tetrahydrofurfuryl hemialkylacetals can be achieved within 20 min by reaction of Furfural in alcoholic solutions at 60 °C and 0.3 MPa of hydrogen. The mechanism of reductive acetalization of Furfural into tetrahydrofurfuryl hemialkylacetals is proposed.
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carbon supported pd cu catalysts for highly selective rearrangement of Furfural to cyclopentanone
Applied Catalysis B-environmental, 2016Co-Authors: Milan Hronec, Katarína Fulajtárová, Edmund Dobročka, Tomas Sotak, I Vavra, Matej MicusikAbstract:Abstract The aqueous phase hydrogenation of Furfural to cyclopentanone was investigated using carbon supported Pd–Cu catalysts prepared by various methods. The most active and selective Pd–Cu catalysts were obtained using electroless plating procedure of deposition of copper in the presence of tartrate carboxylate ligands. It is an alternative and promising way to deposit metal nanoparticles onto the surfaces of porous solid supports. As the XRD data revealed in these catalysts beside metallic palladium with the particle sizes 6.8 nm the copper exist mainly in Cu+ oxidation state as Cu2O and the metallic copper is practically absent. The selectivity to cyclopentanone was enhanced gradually by the addition of 3, 5 and 10 wt% of copper precursor on the pre-reduced 5%Pd/C catalyst. An appropriate Pd0 and Cu+ distribution is presumed to be a key in gaining excellent catalytic activity. Under reaction conditions where mass-transfer effects were eliminated the Furfural conversion about 98% and cyclopentanone yield 92.1 mol% were achieved using only 1 wt% concentration of 5%Pd–10%Cu/C catalyst and reaction time 1 h. According to the proposed mechanism the dominant parameters responsible for reaching very high selectivity of cyclopentanone are (i) very high yield of primary formed furfuryl alcohol and (ii) higher rate of its subsequent conversion to cyclopentanone via the pathway not involving 4-hydroxy-2-cyclopentenone as the main intermediate.
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aqueous phase hydrogenation of Furfural to furfuryl alcohol over pd cu catalysts
Applied Catalysis A-general, 2015Co-Authors: Katarína Fulajtárová, Milan Hronec, Edmund Dobročka, Tomas Sotak, I Vavra, Maria OmastovaAbstract:Abstract A series of Pd, Cu and bimetallic Pd–Cu catalysts with different metals loadings on various supports were prepared for the selective hydrogenation of Furfural to furfuryl alcohol in water as a solvent. In the literature are almost missing the data about the selective hydrogenation of Furfural in water. Among the catalysts screened, bimetallic Pd–Cu catalysts supported on MgO and Mg(OH) 2 prepared by electroless plating method showed the highest conversion and selectivity to furfuryl alcohol. The catalysts 5% Pd–5% Cu supported on MgO or Mg(OH) 2 exhibited at 110 °C and 0.6 MPa of hydrogen complete conversion of Furfural and higher than 98% selectivity toward furfuryl alcohol after 80 min of reaction. The complete conversion of Furfural and the same selectivity could be achieved after five catalytic cycles without extra catalyst treatment or reactivation. Based on physico-chemical characterization the role of Cu loading on the performance of bimetallic Pd–Cu catalysts was discussed. We assume that over Pd–Cu catalyst prepared by electroless plating method on the surface are present monometallic Pd 0 sites and closely interacting bimetallic Pd 0 –Cu 2 O catalytic sites. The Cu + sites participate on activation of C O group in Furfural. The interaction between active metal species and the support also influence the performance of catalyst.
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selective transformation of Furfural to cyclopentanone
Catalysis Communications, 2012Co-Authors: Milan Hronec, Katarína FulajtárováAbstract:Abstract An entirely new route for highly selective preparation of cyclopentanone from Furfural is described. It has been found that Furfural dissolved in water is converted to cyclopentanone with very high selectivity at temperatures above 140 °C and hydrogen pressures > 30 bar. The selectivity of this reaction is strongly influenced by the heterogeneous catalyst and depends on the reaction conditions. Prolongation of the reaction time leads to the hydrogenation of cyclopentanone to cyclopentanol. If instead of water other solvents are used, the main products of reaction are well known hydrogenated derivatives of Furfural, i.e. furfuryl alcohol, tetrahydrofurfuryl alcohol, 2-methylfuran and 2-methyltetrahydrofuran. In the presence of 5% Pt/C catalyst, 76.50 mol% yield of cyclopentanone (81.32 mol% comprehensive yield of cyclopentanone and cyclopentanol) is obtained after 30 min of reaction at 160 °C and a hydrogen pressure of 80 bar.
