Catalytic Transfer Hydrogenation Of Furfural Research Articles

Highly active, ultra-low loading single-atom iron catalysts for catalytic transfer hydrogenation

Highly effective and selective noble metal-free catalysts attract significant attention. Here, a single-atom iron catalyst is fabricated by saturated adsorption of trace iron onto zeolitic imidazolate framework-8 (ZIF-8) followed by pyrolysis. Its performance toward catalytic transfer hydrogenation of furfural is comparable to state-of-the-art catalysts and up to four orders higher than other Fe catalysts. Isotopic labeling experiments demonstrate an intermolecular hydride transfer mechanism. First principles simulations, spectroscopic calculations and experiments, and kinetic correlations reveal that the synthesis creates pyrrolic Fe(II)-plN3 as the active center whose flexibility manifested by being pulled out of the plane, enabled by defects, is crucial for collocating the reagents and allowing the chemistry to proceed. The catalyst catalyzes chemoselectively several substrates and possesses a unique trait whereby the chemistry is hindered for more acidic substrates than the hydrogen donors. This work paves the way toward noble-metal free single-atom catalysts for important chemical reactions.

Efficient Cu/FeOx catalyst with developed structure for catalytic transfer hydrogenation of furfural

Design of efficient and easy-recycling copper catalysts for furfural hydrogenation provides alternative approaches for high-value added chemicals and fuel. In this work, the catalytic transfer hydrogenation of furfural was catalyzed by magnetic Cu/FeOx catalysts via sol–gel method to produce 2-methylfuran with high yield. Homogeneous Cu-Fe-Ox composition could be constructed in the calcined precursor. The growth and evolution of metal centers were modulated and monitored during thermal treatments. The synergy between CuO and FeOx rationally affected the reducibility of the catalyst precursors. After the deliberate two-step-thermal activation, CuO was readily reduced and extruded from FeOx host matrix via phase segregation to give fine Cu particles fastened by FeOx supporting layers. Both experiments and simulation explicitly confirmed the facile isopropanol dehydrogenation to donate hydrogen via small Cu clusters. The dehydroxylation pathway was preferentially happened on furfuryl alcohol with lower activation energy.

Efficient Cu/Feox Catalyst with Developed Structure for Catalytic Transfer Hydrogenation of Furfural

Efficient Cu/Feox Catalyst with Developed Structure for Catalytic Transfer Hydrogenation of Furfural

Defect-Engineered Mof-808 with Highly Exposed Zr Sites as Highly Efficient Catalysts for Catalytic Transfer Hydrogenation of Furfural

Defect-Engineered Mof-808 with Highly Exposed Zr Sites as Highly Efficient Catalysts for Catalytic Transfer Hydrogenation of Furfural

Facile Preparation of Oxygen-Vacancy-Mediated Mn3O4 for Catalytic Transfer Hydrogenation of Furfural

The conversion of biobased furfural (FF) into furfuryl alcohol (FA) has immense industrial significance; however, the catalyst preparation methods for the conversion of FF to FA are demanding. We d...

Highly efficient catalytic transfer hydrogenation of furfural over defect-rich amphoteric ZrO2 with abundant surface acid-base sites.

Currently, the catalytic transformation and utilization of biomass-derived compounds are of great importance to the alleviation of environmental problems and sustainable development. Among them, furfural alcohol derived from biomass resources has been found to be one of the most prospective biomass platforms for high-value chemicals and biofuels. Herein, high-surface-area ZrO2 with abundant oxygen defects and surface acid-base sites was synthesized and used as a heterogeneous catalyst for the catalytic transfer hydrogenation of furfural into furfural alcohol using alcohol as a hydrogen donor. The as-synthesized ZrO2 exhibited excellent catalytic performance with 98.2% FA conversion and 97.1% FOL selectivity, even comparable with that of a homogeneous Lewis acid catalyst. A series of characterization studies and experimental results revealed that acid sites on the surface of ZrO2 could adsorb and activate the C[double bond, length as m-dash]O bond in furfural and base sites could facilitate the formation of alkoxide species. The synergistic effect of surface acid-base sites affords a harmonious environment for the reaction, which is crucial for catalytic transfer hydrogenation of furfural with high efficiency. Furthermore, the as-prepared ZrO2 catalyst also exhibited a potential application for the efficient catalytic transfer hydrogenation of a series of biomass-derived carbonyl compounds.

Catalytic Transfer Hydrogenation of Furfural over CuNi@C Catalyst Prepared from Cu–Ni Metal-Organic Frameworks

Cu/Ni-based metal-organic frameworks (CuNi@BTC) were prepared with benzene-1,3,5-tricarboxylate (H3BTC) as the organic ligand via the solvothermal method, and were then calcinated under N2 atmosphere to form C-coated CuNi catalysts (CuNi@C). TEM showed that carbon material on the surface of CuNi@C was a graphene-like structure. Then transfer hydrogenation of furfural catalyzed by CuNi@C was tested with alcohols as the hydrogen donor to optimize the Cu : Ni ratio, metal : organic ligand ratio, solvothermal synthesis, and calcination conditions. It was found that strong synergistic effect between Cu and Ni in the CuNi@C significantly enhanced the furfural transfer hydrogenation activity and raised the furfural selectivity. The reaction conditions of furfural transfer hydrogenation such as catalyst dosage, hydrogen donor, reaction temperature, and reaction time were studied. The catalytic mechanism for CTH of FF over CuNi@C catalyst was discussed.

One-Pot Cascade Conversion of Renewable Furfural to Levulinic Acid over a Bifunctional H3PW12O40/SiO2 Catalyst in the Absence of External H2

The conversion of biomass-derived furfural (FUR) to levulinic acid (LA), a versatile platform chemical, involves catalytic hydrogenation of FUR followed by acid hydrolysis to LA. However, this two-step process demands expensive separation and purification of the furfuryl alcohol (FAL) intermediate. Herein, we demonstrate an ingenious catalytic strategy for the one-pot cascade conversion of FUR to LA over a bifunctional catalyst without using pure external H2. Isopropyl alcohol (IPA) served a dual role as a hydrogen donor and solvent while inhibiting the side reactions. Catalysts with a tunable surface area and acidity were synthesized by impregnating different percentages of H3PW12O40 (heteropolyacid) over a SiO2 support. The bifunctionality of the H3PW12O40/SiO2 catalyst is ascribed to the mutual coexistence of Lewis and Bro̷nsted acid sites. The Lewis acid sites imparted by active W metal sites adsorb hydrogen proton for catalytic transfer hydrogenation of FUR to FAL, while the predominant Bro̷nsted acid sites catalyze the hydrolysis of FAL to LA. Consequently, H3PW12O40/SiO2 revealed to be a potential catalyst producing an ∼51% LA yield under optimized reaction conditions. Moreover, the catalyst was found to be reusable for three catalytic cycles. This study paves the way to develop future biorefinery, particularly direct conversion of FUR to LA over a bifunctional catalyst with a liquid H-donor, in an environmentally benign manner and comply with the green chemistry principles.

High Performance and Sustainable Copper-Modified Hydroxyapatite Catalysts for Catalytic Transfer Hydrogenation of Furfural

Designing and developing non-noble metal-based heterogeneous catalysts have a substantial importance in biomass conversion. Meerwein-Ponndorf-Verley (MPV) reaction is a significant pathway for eco-friendly catalytic transfer hydrogenation (CTH) of biomass derived furfural into furfuryl alcohol. In this work, a series of copper-supported hydroxyapatite (HAp) catalysts with different copper loadings (2–20 wt.%) were prepared by a facile impregnation method and tested in the reduction of furfural to furfuryl alcohol using 2-propanol as a hydrogen donor. The structural and chemical properties of the synthesised catalysts were analysed by using various techniques (XRD, N2 sorption, SEM, TEM, UV-DRS, ICP, FTIR, TPR, TPD-CO2 and N2O titration). The effect of copper loading was found to be significant on the total performance of the catalysts. The results demonstrate that 5CuHAp catalyst possess highly dispersed copper particles and high basicity compared to all other catalysts. Overall, 5CuHAp exhibited highest conversion (96%) and selectivity (100%) at 140 °C at 4 h time on stream. The optimised reaction conditions were also determined to gain the high activity.

Highly efficient catalytic transfer hydrogenation of biomass-derived furfural to furfuryl alcohol using UiO-66 without metal catalysts

In this paper, the as-prepared metal-organic frameworks material UiO-66 and other Zr-MOFs were directly used as catalytic transfer hydrogenation (CTH) catalysts to catalyze furfural (FF) to furfuryl alcohol (FAL) with 2-propanol (IPA) acted as both solvent and hydrogen donor. The results showed that the as-prepared UiO-66 had satisfactory catalytic activity and selectivity in yielding FAL (97 %) from the CTH of FF at 140 °C within 5 h. Moreover, the as-prepared UiO-66 exhibited relatively stable catalytic activity over five cycles and easy regeneration. Interestingly, UiO-66 was also applicable for the CTH of the other aldehydes such as 5-hydroxymethyfurfural, 5-methylfurfural, 4-methoxybenzaldehyde, and n-hexanal to the corresponding alcohols, affording high product yields up to 98 %. This work provides a green, simple and sustainable process for the catalytic production of FAL from biomass-based furfural, which has certain significance for the sustainable utilization of biomass.

Catalytic transfer hydrogenation of furfural to furfuryl alcohol over Fe3O4 modified Ru/Carbon nanotubes catalysts

In this study, magnetic Fe3O4 modified Ru/Carbon nanotubes (CNTs) catalysts were used to achieve the catalytic transfer hydrogenation of furfural (FF) to furfuryl alcohol (FFA), with alcohols as the solvent and hydrogen donors. According to the result of the catalyst characterization, Fe3O4 promoted the formation of Ru0 species. The effects of Fe3O4 loading and different hydrogen donors on the catalytic transfer hydrogenation of FF were tested, and the reaction parameters and catalyst stability were also analyzed. It is found that Fe3O4 effectively enhanced the activity of Ru/CNTs in catalytic transfer hydrogenation of FF, the catalytic activity was optimized at the Fe3O4 loading of 5 wt%, and the optimal hydrogen donor was i-propanol. Moreover, the Ru–Fe3O4/CNTs could be easily collected for further use and possessed excellent stability. The mechanism of the catalytic transfer hydrogenation of FF using Ru–Fe3O4/CNTs was discussed, and the corresponding catalyst activity groups included metal Ru sites and RuOx-Fe3O4 Lewis acid sites, which account for the excellent catalytic activity of transfer hydrogenation.

Porous Zirconium Hydroxyphosphonoacetate: Catalyst for Conversion of Furfural into Furfuryl Alcohol

AbstractCatalytic transfer hydrogenation (CTH) of the C=O bond has been considered to be one of the most important processes for the synthesis of fuels and chemicals. In this study, zirconium hydroxyphosphonoacetate (Zr‐HPAA) was synthesized by solvent‐thermal method for the transfer hydrogenation of furfural (FF) to furfuryl alcohol. As expected, the Zr‐HPAA, which comprises P−O‐Zr and C−O‐Zr linkages, shows high activity for catalytic transfer hydrogenation of FF to FA. Besides, the effects of time, temperature, catalyst dosage and solvent on the reaction were investigated in detail, with FF conversion (98%) and FA yield (96%) at 150 °C in 1.5 h. The activation energy (Ea) of the reaction was calculated as 47.04 kJ/mol and the lower activation energy was associated to the high catalytic activity of Zr‐HPAA. It is easy to separate catalyst after the reaction and the catalyst exhibits high activity for at least five reaction cycles.

Porous Zr–Thiophenedicarboxylate Hybrid for Catalytic Transfer Hydrogenation of Bio-Based Furfural to Furfuryl Alcohol

Furfural (FAL) is one of the most important biomass-derived platform compounds. The catalytic transformation of FAL was investigated with three porous Zr–thiophenedicarboxylate hybrids for the production of furfuryl alcohol (FOL). Three Zr-based catalysts, including DUT-67(Zr), DUT-68(Zr) and DUT-69(Zr) were synthesized through a facile assembly of 2,5-thiophenedicarboxylate acid with ZrCl4 using the acetic acid as a modulator under hydrothermal conditions. These catalysts were also characterized using FT-IR, XRD, SEM, TEM, N2 adsorption–desorption, XPS and TG. The specific surface area of the DUT-69(Zr) is smaller than that of the DUT-68(Zr) and slightly larger than that of the DUT-67(Zr), but it has a relatively large pore volume and pore diameter. Although all three catalysts showed excellent catalytic activity towards the catalytic transfer hydrogenation of FAL into FOL, the DUT-69(Zr) material has slightly higher catalytic activity than the other two catalysts. Besides, considering the cost of catalyst preparation, the DUT-69(Zr) material was used as the optimal catalyst and studied in detail. A high FOL yield of 92.2% at 95.9% FAL conversion was achieved at 120 °C for 4 h over DUT-69(Zr). Meanwhile, the DUT-69(Zr) could be reused more than six times with a minor decrease in catalytic activity. Finally, a plausible mechanism for catalytic transfer hydrogenation of carbonyl compounds to produce corresponding alcohols was presented based on the results of the experiments and previous reports.

Catalytic Transfer Hydrogenation of Furfural for the Production of Ethyl Levulinate: Interplay of Lewis and Brønsted Acidities

AbstractEthyl levulinate is sought after due to its applications as a fuel additive in biodiesel fuels. Currently it's industrially produced using harmful, highly reactive acids like H2SO4 and HCl, which are used to produce levulinic acid, the common precursor used for EL production. Herein, ethyl levulinate is produced from the synergistic effect of Brønsted and Lewis acids, which catalyze the hydrogenation of furfural leading to the alternative precursor for EL production, furfuryl alcohol. The subsequent ethanolysis reaction of furfuryl alcohol to produce EL, is also enhanced by using an optimal ratio of Brønsted to Lewis acids. Ethanol is chosen as the sacrificial hydrogen donor for proton transfer hydrogenation since it is environmentally friendly, more abundant and affordable than other alcohols that are commonly used for large‐scale production processes. The tandem catalytic reaction can be effectively used to sustainably and responsibly produce ethyl levulinate in relatively short reaction times.

Catalytic transfer hydrogenation of bio-based furfural by palladium supported on nitrogen-doped porous carbon

Highly porous carbon was prepared via a zeolite hard templating route. Subsequent melamine treatment produced nitrogen-functionalized carbon (NPC), which was used as a support to anchor Pd nanoparticles (Pd/NPC) of sizes 2–4 nm using the chemical reduction method. Various analytical techniques were used to characterize the textural properties, structure, and chemical nature of the catalyst. Pd/NPC was then employed as a catalyst for the transfer hydrogenation of biomass-derived furfural (FF) to furfuryl alcohol (FFA) with alcohol as a hydrogen donor, and the effect of temperature, hydrogen donor species, reaction time, and catalysts loading were investigated. The Pd/NPC catalyst was reusable up to five times without any apparent loss of its activity and selectivity. A possible mechanistic pathway for the catalytic transfer hydrogenation of FF over Pd/NPC catalyst was proposed.

Batch versus Continuous Flow Performance of Supported Mono‐ and Bimetallic Nickel Catalysts for Catalytic Transfer Hydrogenation of Furfural in Isopropanol

AbstractFurfural takes an important position in hemicelluloses biorefinery platforms. It can be converted into a wide range of chemicals. One important valorization route is the catalytic hydrogenation. Whereas molecular hydrogen is mostly used in industrial hydrogenation processes, recent studies also showed that alcohols can be used as reductants from which hydrides can be transferred catalytically to furfural. This process is often assisted by the formation of significant amounts of side products, in despite of high yields to the hydrogenolysis product 2‐methylfuran. The present work explores the catalytic behavior in batch and continuous flow of mono‐ and bimetallic nickel catalysts supported on activated carbon for the catalytic transfer hydrogenation of furfural in isopropanol.

Catalytic Transfer Hydrogenation of Furfural to 2-Methylfuran and 2-Methyltetrahydrofuran over Bimetallic Copper-Palladium Catalysts.

The catalytic transfer hydrogenation of furfural to the fuel additives 2-methylfuran (2-MF) and 2-methyltetrahydrofuran (2-MTHF) was investigated over various bimetallic catalysts in the presence of the hydrogen donor 2-propanol. Of all the as-prepared catalysts, bimetallic Cu-Pd catalysts showed the highest catalytic activities towards the formation of 2-MF and 2-MTHF with a total yield of up to 83.9 % yield at 220 °C in 4 h. By modifying the Pd ratios in the Cu-Pd catalyst, 2-MF or 2-MTHF could be obtained selectively as the prevailing product. The other reaction conditions also had a great influence on the product distribution. Mechanistic studies by reaction monitoring and intermediate conversion revealed that the reaction proceeded mainly through the hydrogenation of furfural to furfuryl alcohol, which was followed by deoxygenation to 2-MF in parallel to deoxygenation/ring hydrogenation to 2-MTHF. Finally, the catalyst showed a high reactivity and stability in five catalyst recycling runs, which represents a significant step forward toward the catalytic transfer hydrogenation of furfural.

Liquid-Phase Catalytic Transfer Hydrogenation of Furfural over Homogeneous Lewis Acid-Ru/C Catalysts.

The catalytic performance of homogeneous Lewis acid catalysts and their interaction with Ru/C catalyst are studied in the catalytic transfer hydrogenation of furfural by using 2-propanol as a solvent and hydrogen donor. We find that Lewis acid catalysts hydrogenate the furfural to furfuryl alcohol, which is then etherified with 2-propanol. The catalytic activity is correlated with an empirical scale of Lewis acid strength and exhibits a volcano behavior. Lanthanides are the most active, with DyCl3 giving complete furfural conversion and a 97 % yield of furfuryl alcohol at 180 °C after 3 h. The combination of Lewis acid and Ru/C catalysts results in synergy for the stronger Lewis acid catalysts, with a significant increase in the furfural conversion and methyl furan yield. Optimum results are obtained by using Ru/C combined with VCl3 , AlCl3 , SnCl4 , YbCl3 , and RuCl3 . Our results indicate that the combination of Lewis acid/metal catalysts is a general strategy for performing tandem reactions in the upgrade of furans.