Hydrogenation Of Furfural Research Articles

Enhanced Cyclopentanone Yield from Furfural Hydrogenation: Promotional Effect of Surface Silanols on Ni-Cu/m-Silica Catalyst

A direct alkaline hydrothermal method was used to synthesize mono- and bimetallic Ni and Cu on mesoporous silica (m-SiO2) as catalysts for the hydrogenation of furfural (FAL) to cyclopentanone (CPO). The catalysts were characterized by XRD, FTIR, H2-TPR, SEM, TEM, HR-TEM, XPS, ICP, BET, and CHN analysis. The results demonstrate that the addition of Cu metal improved the reducibility of Ni catalysts and revealed Ni-Cu alloy formation over m-SiO2. Furthermore, XPS and FTIR results reveal that the silanol groups on the catalyst surface play an important role in the ring rearrangement of furfuryl alcohol. Hence, the effect of silanol groups in the FOL rearrangement was studied in detail. Among the catalysts at fixed metal loading of 20 wt.%, Ni5Cu15/m-SiO2 catalyzed the formation of CPO as the main product due to the synergy of Ni-Cu alloy and surface silanol groups. Ni5Cu15 supported on a commercial mesoporous silica (Ni5Cu15/C-SiO2) showed inferior performance compared with the Ni5Cu15/m-SiO2 catalyst for the FAL hydrogenation. Reaction temperature and time were also optimized for the enhanced CPO yield over Ni5Cu15/m-SiO2. The Ni5Cu15/m-SiO2 catalyst is durable, as demonstrated by stability tests over multiple reuses. This effective and flexible NixCuy on m-SiO2 catalyst provides an effective candidate for efficient upgrading of furanics in selective hydrogenation reactions.

Time and Potential‐Resolved Comparison of Copper Disc and Copper Nanoparticles for Electrocatalytic Hydrogenation of Furfural

Herein, a comparative analysis of two case example catalysts for electrocatalytic hydrogenation (ECH) of furfural under acidic conditions, namely a copper polycrystalline disc and copper nanoparticles dispersed on carbon support, is performed. To gain a detailed insight on ECH trends, a task‐specific methodology is employed based on electrochemistry–mass spectrometry coupling, which enabled time‐ and potential‐resolved detection of volatile ECH products, i.e., 2‐methylfurane (2‐MF) and H2. In this way, the ability to elucidate potential‐dependent product distribution for the two catalysts, namely faradaic efficiency, is achieved. Accordingly, the nanoparticulate analog is significantly more active toward competitive hydrogen evolution reaction and 2‐MF production, whereas the polycrystalline sample is more selective toward furfuryl alcohol. The observed differences in ECH are ascribed to alterations in surface domains, which is supported by surface‐sensitive lead underpotential deposition characterization.

Understanding hydrogen pressure control of furfural hydrogenation selectivity on a Pd(1 1 1) model catalyst

We investigate the postulate that hydrogen pressure influences the furfural hydrogenation selectivity on palladium to form decarbonylation products at low hydrogen pressures, but 2-methyl furan at higher pressures. This change is caused by co-adsorbed hydrogen changing the orientation of adsorbed furfural; low hydrogen coverages favor flat-lying furfural, higher coverages form tilted species. This was tested for hydrogenation of furfural on a Pd(111) single crystal. The product distribution agreed with the postulate, with 100% selectivity to furan and tetrahydrofuran for low hydrogen pressures, with 2-methyl furan increasing with hydrogen pressure. The origin of the effect is explored using reflection–absorption infrared spectroscopy. This showed that co-adsorbed hydrogen influenced the orientation in a way predicted by theory. It was also found that other co-adsorbates displayed similar effects implying that a range of molecules in the reaction mixture could have significant effects on the furfural selectivity.

AQUEOUS-PHASE HYDROGENATION OF FURFURAL IN THE PRESENCE OF SUPPORTED METALLIC CATALYSTS OF DIFFERENT TYPES. A REVIEW

Hydrogenation of furfural in the presence of heterogeneous catalysts has recently attracted increased interest as a method for the synthesis of oxygen-containing compounds of various classes based on renewable raw materials. The composition of the catalyst and the conditions of its preparation essentially determine which of the routes of reductive conversions during the hydrogenation of furfural will be predominant. The present review summarizes and analyzes methods for controlling the physicochemical and functional properties of various metal catalysts with an emphasis on Pd-, Ni-, Co, and Cu-containing catalytic compositions, as the most common and practically significant in the hydrogenation of furfural. Many examples show the influence of the nature of the support, the composition of the active metal precursor, and the conditions for the formation of metal nanoparticles on the activity and selectivity of supported catalysts in the reductive conversions of furfural under aqueous-phase hydrogenation conditions. Promising directions of research on the development of methods for the synthesis of efficient catalysts with controlled functional properties in the hydrogenation of furfural are considered. The bibliography includes 127 references.

Aqueous-Phase Hydrogenation of Furfural in the Presence of Supported Metal Catalysts of Different Types. A Review

Aqueous-Phase Hydrogenation of Furfural in the Presence of Supported Metal Catalysts of Different Types. A Review

Catalysts Based on Ni(Mg)Al-Layered Hydroxides Prepared by Mechanical Activation for Furfural Hydrogenation

Ni(Mg)Al-layered hydroxides with molar ratios of (Ni + Mg)/Al = 2, 3, 4 and Ni/(Ni + Mg) = 0.1, 0.3, 0.5, 0.7 were synthesized by mechanochemical activation. It has been proven that the phase composition of the samples was presented by a single hydrotalcite phase up to Ni/(Ni + Mg) = 0.5. For the first time, catalysts based on Ni(Mg)Al-layered hydroxides prepared by a mechanochemical route have been studied in the reaction of furfural hydrogenation. The correlation between furfural conversion, the selectivity of the products, and the composition of the catalysts was established. The effect of phase composition, surface morphology, and microstructure on the activity of the catalysts was shown by XRD, SEM, and TEM. It was found that catalysts with Ni/(Ni + Mg) = 0.5 have the highest furfural conversion. Herewith, the product selectivity can be regulated by the (Ni + Mg)/Al ratio.

Porous Hollow Nanostructure Promoting the Catalytic Performance and Stability of Ni3P in Furfural Hydrogenation

In the processes of hydrogenation, the accurate control of product distribution is crucial to the high-value conversion of furfural. Herein, Ni3P catalysts were prepared by phase separation synthesis with porous hollow nanospheres and employed as catalysts for the hydrogenation of furfural. Over the Ni3P-400 catalyst, furfural could be transformed completely with 95.6% selectivity toward furfuryl alcohol under 120 °C and 1.6 MPa for 4 h. The deactivation of the Ni3P-400 catalyst was not observed during 8-run recycling tests. Moreover, using other carbonyl compounds derived from biomass as substrates, excellent catalytic performance was also obtained. Such exceptional features make the Ni3P-400 catalyst promising for industrial applications not only in hydrogenation of furfural but also in hydrogenation of other carbonyl substrates.

Furfural hydrogenation into tetrahydrofurfuryl alcohol under ambient conditions: Role of Ni-supported catalysts and hydrogen source

Herein hydrogenation of biomass-derived furfural (FAL) catalyzed by Ni-supported catalysts and NaBH4 into tetrahydrofurfuryl alcohol (THFA) demonstrated in aqueous media under ambient reaction conditions. The activity of various Ni-supported catalysts (Ni/active carbon (Ni/AC); Ni/carbon black (Ni/CB); Ni/bone char (Ni/BC); Ni/C (derived from Ni-MOF)) compared for FAL hydrogenation. Ni/AC exhibited a high activity towards FAL hydrogenation into THFA (99% yield) compared to all other Ni-supported catalysts tested in this study. The results showed that hydrophobic nature of the AC support in Ni/AC, higher specific BET surface area, and smaller Ni particle size enhance the FAL hydrogenation proficiency towards THFA in aqueous media under milder reaction conditions. The FAL is efficiently hydrogenated with NaBH4 (hydrogen source). On the contrary, FAL is not hydrogenated in pure H2, suggesting a crucial role of NaBH4 in FAL hydrogenation. For the first time, the role of NaBH4 is investigated in detail for the hydrogenation of biomass-derived furans. The interaction of NaBO2 produced from NaBH4 with furfuryl alcohol (FOL) enhances the adsorption of the furan ring of FOL on the Ni surface via parallel geometry, resulting in efficient furan ring hydrogenation of FOL into THFA.

Synthesis of Alumina Supported Pt-SnO2 Hybrid Nanostructures by In Situ Transformation of PtSn Alloy Nanoparticles and Their Application as Highly Efficient Catalysts for Selective Hydrogenation of Furfural

In this work, PtSn alloy nanoparticles were synthesized by coreduction of Pt and Sn precursors by ethylene glycol in the presence of stabilizing agents and then were in situ transformed into Pt-SnO2 hybrid nanostructures on alumina supports by calcination. Relative to Pt/Al2O3, Pt1-(SnO2)0.3/Al2O3 demonstrates improved catalytic efficiency for furfuryl alcohol production by furfural hydrogenation. Under the H2 pressure of 1.0 MPa, 100 °C, 3.0 h, and furfural/Pt molar ratio of 1435/1, the furfuryl alcohol yields could approach 98.2%. The enhancement of catalytic performance of the Pt-SnO2/Al2O3 could be ascribed to the formation of the close contact Pt-SnO2 interfaces, which is highly active for furfural hydrogenation due to the synergistic effect between Pt and SnO2.

Highly dispersed Pt on partial deligandation of Ce-MOFs for furfural selective hydrogenation

Metal-organic frameworks (MOFs) have been extensively investigated as noble metal nanoparticle supports for selective hydrogenations. However, because of small-sized micropores and organic ligands present in MOFs, interactions between inorganic nodes and noble metals are normally weak and the accessibility of active sites is seriously limited. To address these problems, in this study, a partial deligandation strategy is proposed where Pt/CeO2-270 is obtained by a partial decomposition of Ce-MOFs at 270 °C, then the Pt nanoparticles are deposited by atomic layer deposition (ALD) method. In comparison with the full deligandation of Ce-MOFs at 600 °C (CeO2-600), the CeO2-270 catalyst with residual organic ligands exhibits larger surface area, extensive porous structure, abundant Ce3+ and oxygen vacancy, which stabilize the highly dispersed small Pt nanopartciles. These unique structural features enable the Pt/CeO2-270 catalyst to display different furfural (FAL) adsorption configuration, and show excellent FAL conversion (100%) and high selectivity (97.3%) for furfuryl alcohol (FOL). This work provides a strategy to support highly dispersed Pt nanoparticles on MOFs-derived porous materials prepared by partial deligandation strategy, achieving excellent catalytic performance and chemoselectivity for selective hydrogenation reactions.

The structure-sensitive of Cu catalyst for furfural conversion to furfuryl alcohol: A theoretical study

The structure-sensitive of Cu catalyst for furfural hydrogenation to furfuryl alcohol was explored by employing Cu(111) and Cu(211) model systems. Herein, the adsorption behavior of reactants and intermediates, and the possible reaction mechanism of furfuryl alcohol formation were investigated. For furfuryl alcohol formation, the preferred pathway is F-CHO + 2H→F-CH2O + H→F-CH2OH, in which the second H addition is the rate-determining step. Meanwhile, Cu(211) surface exhibits higher activity to furfuryl alcohol formation than that on Cu(111) surface. According to our analysis, the undercoordinated sites on the Cu(211) surface could facilitate H2 dissociation and stabilize the adsorbed furfural, thereby promoting the furfural hydrogenation and the furfuryl alcohol formation. This work provides a feasible approach for regulating the catalytic activity and selectivity in furfural conversion.

The Role of Copper in the Hydrogenation of Furfural and Levulinic Acid.

Currently, there is a great interest in the development of sustainable and green technologies for production of biofuels and chemicals. In this sense, much attention is being paid to lignocellulosic biomass as feedstock, as alternative to fossil-based resources, inasmuch as its fractions can be transformed into value-added chemicals. Two important platform molecules derived from lignocellulosic sugars are furfural and levulinic acid, which can be transformed into a large spectrum of chemicals, by hydrogenation, oxidation, or condensation, with applications as solvents, agrochemicals, fragrances, pharmaceuticals, among others. However, in many cases, noble metal-based catalysts, scarce and expensive, are used. Therefore, an important effort is performed to search the most abundant, readily available, and cheap transition-metal-based catalysts. Among these, copper-based catalysts have been proposed, and the present review deals with the hydrogenation of furfural and levulinic acid, with Cu-based catalysts, into several relevant chemicals: furfuryl alcohol, 2-methylfuran, and cyclopentanone from FUR, and γ-valerolactone and 2-methyltetrahydrofuran from LA. Special emphasis has been placed on catalytic processes used (gas- and liquid-phase, catalytic transfer hydrogenation), under heterogeneous catalysis. Moreover, the effect of addition of other metal to Cu-based catalysts has been considered, as well as the issue related to catalyst stability in reusing studies.

Reticular Coordination Induced Interfacial Interstitial Carbon Atoms on Ni Nanocatalysts for Highly Selective Hydrogenation of Bio-Based Furfural under Facile Conditions.

A rational design of transition metal catalysts to achieve selective hydrogenation of furfural (FFR) to tetrahydrofurfuryl alcohol (THFA) under facile conditions is a promising option. In this work, a series of Ni catalysts were synthesized by controlled thermal treatment of Ni-based metal-organic frameworks (MOFs), with the purpose of modulating the interface of nickel nanoparticles by the reticular coordination in MOF precursors. The catalytic performance indicates that Ni/C catalyst obtained at 400 °C exhibits efficient conversion of FFR (>99%) and high selectivity to THFA (96.1%), under facile conditions (80 °C, 3 MPa H2, 4.0 h). The decomposition of MOF at low temperatures results in highly dispersed Ni0 particles and interfacial charge transfer from metal to interstitial carbon atoms induced by coordination in MOF. The electron-deficient Ni species on the Ni surface results in an electropositive surface of Ni nanoparticles in Ni/C-400, which ameliorates furfural adsorption and enhances the hydrogen heterolysis process, finally achieving facile hydrogenation of FFR to THFA.

Aqueous phase hydrogenation of furfural on Ni/TiO2 catalysts: nature of the support phase steers the product selectivity

Titania crystal phases were able to tune the nature of metal through metal–support interaction and acidic sites for surface rearrangement and hydrogenation of furfural.

Efficient and continuous furfural hydrogenation to furfuryl alcohol in a micropacked bed reactor

In this work, continuous furfural hydrogenation to furfuryl alcohol in micropacked bed reactors (μPBRs) is investigated.

Facile synthesis of a high-efficiency NiFe bimetallic catalyst without pre-reduction for the selective hydrogenation reaction of furfural

A high-efficiency nickel–iron bimetallic catalyst (Ni3Fe1 alloy) was synthesized by a facile solvothermal reaction and directly used in furfural hydrogenation without pre-reduction.

Enhancing the catalytic performance of Co-N-C derived from ZIF-67 by mesoporous silica encapsulation for chemoselective hydrogenation of furfural.

Developing Cr-free and non-noble metal catalysts with high activity, selectivity and durability for chemoselective hydrogenation of furfural to furfuryl alcohol is highly desirable yet challenging. In this study, we design a hollow mesoporous Co-N-C@mSiO2 nanostructure derived from ZIF-67 via the encapsulation-pyrolysis strategy. The Co-N-C@mSiO2 catalyst exhibits excellent catalytic performance in the furfural hydrogenation towards furfuryl alcohol with good stability, and is much better than the Co-N-C catalyst originating from plain ZIF-67 and other reported transition metal catalysts. Characterization methods and control experiments show that Co-Nx species rather than Co metal should be catalytically active sites for the above reaction. The enhanced performance is associated with abundant Co-Nx active sites, good mass transport, and the SiO2 shell protection. This work provides a novel and facile strategy for preparing highly efficient non-precious metal catalysts to replace Cr-based and noble metal catalysts for furfural hydrogenation.

Cu/SiO2 synthesized with HKUST-1 as precursor: high ratio of Cu+/(Cu+ + Cu0) and rich oxygen defects for efficient catalytic hydrogenation of furfural to 2-methyl furan.

Cu/SiO2 is one of the most promising catalysts for the furfural (FF) hydrogenation reaction but suffers from the difficulty of tailoring the microstructure and surface properties. Herein, we developed a MOF-derived Cu/SiO2 catalyst (Cu/SiO2-MOF) for FF hydrogenation to 2-methyl furan (2-MF). In comparison with Cu/SiO2 catalysts prepared from ammonia evaporation (Cu/SiO2-AE) and traditional impregnation (Cu/SiO2-TI), the copper species in Cu/SiO2-MOF could not only be anchored on the silica surface via forming Cu-O-Si bonds but also exposed many more active sites. In this way, a higher ratio of Cu+/(Cu+ + Cu0) and richer oxygen defects were constructed via strong metal-support interactions, which were responsible for the superior catalytic performance. In addition, it was found that the solvent effect on product distribution played an important role in adjusting the selectivity to 2-MF and cyclopentanone (CPO). The present work not only provides a deep insight into the catalytic mechanism of Cu/SiO2-MOF for the FF hydrogenation reaction but also sheds light on the design and synthesis of highly efficient catalysts for other heterogeneous catalysis fields.

Continuous conversion of furfural to furfuryl alcohol by transfer hydrogenation catalyzed by copper deposited in a monolith reactor

A polymer monolith catalytic reactor, which is fabricated by anchoring –SO3H groups on the surface of the fibers and by depositing Cu species, exhibits outstanding performance and high stability in continuous transfer hydrogenation of furfural.

Role of lattice strain in bifunctional catalysts for tandem furfural hydrogenation–esterification

This research represents that the bifunctional catalyst (Cu/RHSiO2–Al–Mg) which has the lowest lattice strain can significantly enhance catalytic reactivity such as the furfural conversion into furfural acetate.