Iron oxide encapsulated by ruthenium hydroxyapatite as heterogeneous catalyst for the synthesis of 2,5-diformylfuran

Hydrocarbon Formation from Syngas with In-Operando Monitoring of Cobalt- and Manganese-Based (pre)Catalysts Using X-ray Diffraction

Two-layered metal oxides (LiCoO2 and cobalt-doped K n MnO2, n < 1) were explored as precatalysts for nanoconfined cobalt-based Fischer-Tropsch catalysts for conversion of syngas (CO and H2) to hydrocarbons. Ex situ, in situ, and PDF XRD analyses are presented. Based on in situ XRD analysis, LiCoO2 underwent reduction to predominantly cubic and hexagonal phases of cobalt metal. Reaction with syngas resulted in the generation of carbon, cobalt carbide, and lithium carbonate, in addition to the metallic cobalt phases. In the case of cobalt-doped birnessite, catalyst activation converted the birnessite phase to manganite and the cobalt to elemental cobalt, along with similar lithium and carbon phases. Conversion of syngas to C1 through C7 products was observed. The best conversions were observed for the LiCoO2 precursor catalyst, with generally a low olefin-to-paraffin ratio. While the conversions for the cobalt-doped birnessite precatalyst were generally lower, with lower chain lengths (up to C5), these catalysts gave a strikingly high olefin-to-paraffin ratio: in the best case, greater than 20:1.

Cobalt phthalocyanine (CoPc) anchored on Ti3C2 MXene nanosheets for highly efficient selective catalytic oxidation

Quinclorac is an important precursor for pharmaceutical, agricultural, and synthetic chemistry. The state-of-the-art synthesis of quinclorac via condensation, chlorination and oxidative hydrolysis often uses homogeneous catalysts and strong acid oxidant agents to promote the catalytic oxidation, which requires huge manpower input for the late-stage purification process and is usually environmentally unfriendly. In this work, we successfully fabricated a stable cobalt phthalocyanine (CoPc) Co-based composite (CoPc/Ti3C2) by anchoring CoPc on the surface of Ti3C2 nanosheets for the selective oxidation of 3,7-dichloro-8-dichloro methyl quinoline (3,7-D-8-DMQ) into quinclorac. More impressively, CoPc/Ti3C2-4.5%-Mn-Br exhibits a high selectivity of 91.8% for the catalytic oxidation of 3,7-D-8-DMQ to quinclorac in acetic acid, with a quinclorac yield of 87.5%, which is approximately 2.46 times higher than that of pristine CoPc-Mn-Br. The obtained heterogeneous catalytic system shows good reusability. Detailed mechanistic investigations reveal that the system works through the free radical mechanism via the formation of Co2+/Co3+ redox cycles. This work provides a new understanding for the stabilization of reaction intermediates and facilitates the design of catalysts for selective catalytic oxidation.

Enhanced catalysis of a vanadium-substituted Keggin-type polyoxomolybdate supported on the M3O4/C (M = Fe or Co) surface enables efficient and recyclable oxidation of HMF to DFF

In the reaction of oxidizing 5-hydroxymethylfurfural (HMF), attaining high efficiency and selectivity in the conversion of HMF into DFF presents a challenge due to the possibility of forming multiple products. Polyoxometalates are considered highly active catalysts for HMF oxidation. However, the over-oxidation of products poses a challenge, leading to decreased purity and yield. In this work, metal-organic framework-derived Fe3O4/C and Co3O4/C were designed as carriers for the vanadium-substituted Keggin-type polyoxomolybdate H5PMo10V2O40·35H2O (PMo10V2). In this complex system, spinel oxides can effectively adsorb HMF molecules and cooperate with PMo10V2 to catalyze the aerobic oxidation of HMF. As a result, the as-prepared PMo10V2@Fe3O4/C and PMo10V2@Co3O4/C catalysts can achieve efficient conversion of HMF into DFF with almost 100% selectivity. Among them, PMo10V2@Fe3O4/C exhibits a higher conversion rate (99.1%) under milder reaction conditions (oxygen pressure of 0.8 MPa). Both catalysts exhibited exceptional stability and retained their activity and selectivity even after undergoing multiple cycles. Studies on mechanisms by in situ diffuse reflectance infrared Fourier transform spectroscopy and X-ray photoelectron spectroscopy revealed that the V5+ and Mo6+ in PMo10V2, together with the metal ions in the spinel oxides, act as active centers for the catalytic conversion of HMF. Therefore, it is proposed that PMo10V2 and M3O4/C (M = Fe, Co) cooperatively catalyze the transformation of HMF into DFF via a proton-coupled electron transfer mechanism. This study offers an innovative approach for designing highly selective and recyclable biomass oxidation catalysts.

Immobilization of a trimeric ruthenium cluster in mesoporous chromium terephthalate and its catalytic application

Molecular trimeric ruthenium carboxylate clusters (Ru₃ clusters) have been introduced into the pore channels of mesoporous metal-organic framework chromium terephthalate [MIL-101(Cr)] by employing a facile two-step post-synthetic strategy in which diamine hooks anchored on the framework metal nodes of the MOF are used to covalently immobilize the Ru₃ clusters. The catalytic activity of the isolated Ru₃ clusters in the pore channels of the MOF was significantly improved compared to the bulk counterpart.

Effective Oxidation of 5-Hydroxymethylfurfural to 2,5-Diformylfuran by an Acetal Protection Strategy

An acetal protection strategy for 5-hydroxymethylfurfural (HMF) was used to obtain 2,5-diformyfuran (DFF) using concentrated HMF solutions and a γ-Al₂ O₃ -supported Ru catalyst (Ru/γ-Al₂ O₃ ). The HMF-acetal with 1,3-propanediol can be oxidized to DFF-acetal with a yield of 84.0 % at an HMF conversion of 94.2 % from a 50 wt % solution. In contrast, aerobic oxidation of nonprotected HMF using a 10 wt % solution afforded DFF only in a moderate yield (52.3 %). Kinetic studies indicated that the six-membered ring acetal group not only prevents side reactions but also accelerates aerobic oxidation of the -CH₂ OH moiety to -CHO under retention of the acetal functionality. Organic deposits formed during the reaction explained the significant decrease in the activity of the Ru/γ-Al₂ O₃ catalyst, which could be recovered neither by washing in water or organic solvents, nor by a calcination-reduction treatment. Sonication of the used Ru/γ-Al₂ O₃ catalyst in an aqueous NaOH solution successfully removed the deposits and allowed reuse of the catalyst for at least four times without activity loss.

High-efficiency synthesis of 5-hydroxymethylfurfural and 2,5-diformylfuran from fructose over magnetic separable catalysts

In this work, a sulfonic acid-functionalized magnetic separable solid acid (Fe₃O₄@SiO₂-SO₃H) was synthesized, characterized, and tested for fructose conversion to 5-hydroxymethylfurfural (HMF). Results indicated that the prepared catalyst had a good efficacy for fructose dehydration to HMF due to its larger specific surface area, appropriate acid amount and homogeneous acid distribution. The maximum HMF yield of this work was 96.1 mol%. It was obtained at 120 °C for 1.5 h with 100 mol% fructose conversion. More importantly, the produced HMF could be further in-situ oxidized into 2,5-diformylfuran (DFF) after the replacing of the Fe₃O₄@SiO₂-SO₃H with a ZnFeRuO₄ catalyst, and the highest DFF yield of 90.2 mol% (based on initial fructose) was obtained after reaction another 8.5 h. The production of DFF from fructose through the above two consecutive steps avoids the intermediate HMF separation, which saves time and energy. In addition, both Fe₃O₄@SiO₂-SO₃H and ZnFeRuO₄ catalysts exhibited satisfied stability in the recycling experiments, which can be reused at least for five times with the HMF and DFF yield loss<5.3% and 3.3%, respectively. Finally, the plausible reaction mechanisms for fructose conversion to HMF or DFF over Fe₃O₄@SiO₂-SO₃H or/and ZnFeRuO₄ catalysts were also proposed in this work.

Support-Activity Relationship in Heterogeneous Catalysis for Biomass Valorization and Fine-Chemicals Production

Heterogeneous catalysts are progressively expanding their field of application, from high-throughput reactions for traditional industrial chemistry with production volumes reaching millions of tons per year, a sector in which they are key players, to more niche applications for the production of fine chemicals. These novel applications require a progressive utilization reduction of fossil feedstocks, in favor of renewable ones. Biomasses are the most accessible source of organic precursors, having as advantage their low cost and even distribution across the globe. Unfortunately, they are intrinsically inhomogeneous in nature and their efficient exploitation requires novel catalysts. In this process, an accurate design of the active phase performing the reaction is important; nevertheless, we are often neglecting the importance of the support in guaranteeing stable performances and improving catalytic activity. This review has the goal of gathering and highlighting the cases in which the supports (either derived or not from biomass wastes) share the worth of performing the catalysis with the active phase, for those reactions involving the synthesis of fine chemicals starting from biomasses as feedstocks.

Hydroxyapatite-Supported Polyoxometalates for the Highly Selective Aerobic Oxidation of 5-Hydroxymethylfurfural or Glucose to 2,5-Diformylfuran under Atmospheric Pressure

(NH4 )5 H6 PV8 Mo4 O40 supported on hydroxyapatite (HAP) (PMo4 V8 /HAP (n)) was prepared through the ion exchange of hydroxy groups. This ion exchange favored the oxidative conversion of 5-hydroxymethylfurfural (5-HMF) to 2,5-diformylfuran (DFF) in a one-pot cascade reaction with 96.0 % conversion and 83.8 % yield under 10 mL/min of O2 flow. PMo4 V8 /HAP (31) was used to explore the production of DFF directly from glucose with the highest yield of 47.9 % so far under atmospheric oxygen, whereas the yield of DFF increased to 54.7 % in a one-pot and two-step reaction. These results indicated that the active sites in PMo4 V8 /HAP (31) retained their activities without any interference toward one another, which enabled the production of DFF in a more cost-saving way by only using oxygen and one catalyst in a one-step reaction. Meanwhile, the rigid structure of HAP and strong interaction in PMo4 V8 /HAP (31) allowed this catalyst to be reused for at least six times with high stability and duration.

Imidazole-Functionalized Polyoxometalate Catalysts for the Oxidation of 5-Hydroxymethylfurfural to 2,5-Diformylfuran Using Atmospheric O2

Biomass as a sustainable and abundant carbon source has attracted considerable attention as a potential alternative to petroleum resources. The selective oxidation of 5-hydroxymethylfurfural (HMF), a versatile platform molecule, to value-added 2,5-diformylfuran (DFF) provides an efficient pathway for biomass valorization. Herein, three discrete imidazole-functionalized polyoxometalates (POMs), HPMo₈V^VI₄O₄₀(V^VO)₂[(V^IVO)(IM)₄]₂·nH₂O·(IM)_m (IM = 1-methylimidazole, n = 4, m = 8 for 1; IM = 1-ethylimidazole, n = 4, m = 9 for 2; IM = 1-propylimidazole, n = 0, m = 4 for 3), have been successfully synthesized by a facile solvothermal method and thoroughly characterized by routine techniques. Compounds 1-3 contain a bi-capped pseudo-Keggin {HPMo₈V₄O₄₀(VO)₂} and two imidazole-functionalized {(VO)(IM)₄} groups, which, to our knowledge, represent the first examples of organic-functionalized Mo-V clusters. Compounds 1-3 as heterogeneous catalysts can effectively promote the transformation of HMF to DFF using atmospheric O₂ as oxidant. Under minimally optimized conditions, 95% of HMF was converted by 1 with 95% selectivity for DFF and its catalytic activity was basically maintained after five cycles. Moreover, the important roles of the bi-capped pseudo-Keggin cluster and the functionalized V groups in the selective oxidation of HMF have been explored. According to experimental and spectroscopic results, a three-step oxidation mechanism of HMF to DFF has been proposed.

Work-hardening Photopolymer from Renewable Photoactive 3,3'-(2,5-Furandiyl)bisacrylic Acid

The design of a photopolymer around a renewable furan-derived chromophore is presented herein. An optimised semi-continuous oxidation method using MnO2 affords 2,5-diformylfuran from 5-(hydroxymethyl)furfural in gram quantities, allowing the subsequent synthesis of 3,3'-(2,5-furandiyl)bisacrylic acid in good yield and excellent stereoselectivity. The photoactivity of the diester of this monomer is confirmed by reaction under UV irradiation, and the proposed [2+2] cycloaddition mechanism supported further by TD-DFT calculations. Oligoesters of the photoreactive furan diacid with various aliphatic diols are prepared via chemo- and enzyme-catalysed polycondensation. The latter enzyme-catalysed (Candida antarctica lipase B) method results in the highest Mn (3.6 kDa), suggesting milder conditions employed with this protocol minimised unwanted side reactions, including untimely [2+2] cycloadditions, whilst preserving the monomer's photoactivity and stereoisomerism. The photoreactive polyester is solvent cast into a film where subsequent initiator-free UV curing leads to an impressive increase in the material stiffness, with work-hardening characteristics observed during tensile strength testing.

Oxidation of lignocellulosic platform molecules to value-added chemicals using heterogeneous catalytic technologies

This minireview gives an overview about heterogeneous catalytic technologies for the oxidation of key platform molecules (glucose, 5-hydroxymethylfurfural, furfural and levulinic acid) into valuable chemicals.

Magnetically separable Ru-containing catalysts in supercritical deoxygenation of fatty acids

In the current paper, the possibility of the use of magnetically separable catalysts containing ruthenium oxide species in the supercritical deoxygenation of stearic acid for producing of the second generation of biodiesel is reported. Three different supports (silica, ceria, and hypercrosslinked polystyrene) were used for the stabilization of magnetic nanoparticles (MNPs) and Ru-containing particles. The effect of support on the magnetic properties as well as the catalytic activity of the obtained systems was studied. All synthesized catalysts were shown to provide high stearic acid conversion (up to 95 %). The highest yield of C17+ hydrocarbons (up to 86 %) was observed while using the Ru–Fe3O4-HPS system. Ru–Fe3O4-HPS was characterized by the high values of the specific surface area (364 m2/g) and saturation magnetization (4.5 emu/g). The chosen catalytic system was found to maintain its catalytic activity for a minimum of 10 consecutive cycles.

Highly Efficient Oxidation of 5-Hydroxymethylfurfural to 2,5-Furandicarboxylic Acid with Heteropoly Acids and Ionic Liquids

2,5-Furandicarboxylic acid (FDCA) is regarded as an important bioderived substitute for petrochemically derived terephthalic acid (PTA), which is widely applied in the polymer industry. This work delineates the base-free oxidation of 5-hydroxymethylfurfural (HMF) to FDCA in an ionic liquid/heteropoly acid (IL-HPA) catalytic system. HPAs displayed high activity for selective oxidation; their active center (Mo/V) was activated by O₂ and transformed from oxygen single and double bonds to epoxy groups, resulting in an FDCA yield of 89 % for HPMV₆ (HPM=H₃ PMo₁₂ O₄₀ ) in the presence of [Bmim]Cl (1-butyl-3-methylimidazolium chloride) under optimized reaction conditions. The high solubility of imidazole ILs for FDCA improved the affinity of HMF and the active centers of the catalyst and protected the furan ring from oxidative cleavage. Furthermore, multiple hydrogen bonds simultaneously formed between the electronegative anions and hydroxy protons of HMF, as well as the hydrogen atoms of the imidazole rings and hydroxy groups, promoting the transformation to aldehyde groups. Various starting materials were studied, and a moderate FDCA yield was obtained from glucose. This work provides an interesting IL-HPA catalytic system for the base-free synthesis of FDCA from accessible monosaccharides and illustrates the great potential of FDCA production from renewable carbohydrates.

One-Pot Synthesis of 2,5-Diformylfuran from Fructose by Bifunctional Polyaniline-Supported Heteropolyacid Hybrid Catalysts

We report the preparation of bifunctional hybrid catalysts by supporting H3PMo12O40 (PMo12) heteropolyacid (HPA) on polyaniline (PAN) or formyl-functionalized PAN (F-PAN) for the “one-pot” and “one-step” synthesis of 2,5-diformylfuran (DFF) from fructose via 5-hydroxymethylfurfural (HMF) intermediate. We show that the PMo12 HPA is the main active species for both fructose dehydration and HMF oxidation owing to its Brønsted acidic and redox characters. However, the anchoring of PMo12 on PAN reduces the Brønsted acidity by acid–base interaction between protons in HPA and quinoid diimine structure in PAN, thereby reducing the dehydration performance. We demonstrate that the catalytic dehydration performance of the hybrid catalyst could be strengthened by grafting formyl groups on PAN before HPA anchoring. The highest DFF yield of 76.7% is obtained by conducting the “one-pot” reaction over the 40-PMo12/F3-PAN catalyst at 413 K for 7 h in air, wherein the side-reactions of fructose or HMF degradation and HMF rehydration have been significantly reduced. This hybrid catalyst is reusable without significant activity loss, highlighting the designing of stable inorganic–organic hybrid catalysts for producing valuable hexose-derived platform chemicals.

β-Cyclodextrin engineered γ-Fe2O3@ hydroxyapatite nanocomposite as a novel scaffold for the synthesis of phenacyl derivatives

Magnetic hydroxyapatite (HAp) is being widely investigated for various applications in medical engineering and nanocomposite for transformation reaction. The present work describes an efficient procedure for the synthesis of phenacyl derivatives employing a novel, green and magnetically retrievable nanocomposite via the grafting of β-cyclodextrin moieties on the magnetic hydroxyapatite surface, γ-Fe₂O₃@HAp-CD. The structure and composition of the nanocomposite was performed by different methods and analyzed by Infrared Spectroscopy (FT-IR), Field Emission Scanning Electron Microscopy (FE-SEM), transmission electron microscopy (TEM), Thermo-Gravimetric Analysis (TGA), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS) and Brunauer Emmett Teller (BET) and vibrating sample magnetometry (VSM). Our results indicate that conjugation with β-CD improves the catalytic activity in the reaction.

Selective Oxidation of HMF via Catalytic and Photocatalytic Processes Using Metal-Supported Catalysts

In this study, 5-hydroxymethylfurfural (HMF) oxidation was carried out via both the catalytic and the photocatalytic approach. Special attention was devoted to the preparation of the TiO₂-based catalysts, since this oxide has been widely used for catalytic and photocatalytic application in alcohol oxidation reactions. Thus, in the catalytic process, the colloidal heterocoagulation of very stable sols, followed by the spray-freeze-drying (SFD) approach, was successfully applied for the preparation of nanostructured porous TiO₂-SiO₂ mixed-oxides with high surface areas. The versatility of the process made it possible to encapsulate Pt particles and use this material in the liquid-phase oxidation of HMF. The photocatalytic activity of a commercial titania and a homemade oxide prepared with the microemulsion technique was then compared. The influence of gold, base addition, and oxygen content on product distribution in the photocatalytic process was evaluated.

Selective Oxidation of Biomass-Derived Alcohols and Aromatic and Aliphatic Alcohols to Aldehydes with O2/Air Using a RuO2-Supported Mn3O4 Catalyst

Selective catalytic oxidation of carbohydrate-derived 5-hydroxymethylfurfural, furfuryl alcohol, and various aromatic and aliphatic compounds to the corresponding aldehyde is a challenging task. The development of a sustainable heterogeneous catalyst is crucial in achieving high selectivity for the desired aldehyde, especially using O2 or air. In this study, a RuO2-supported Mn3O4 catalyst is reported for the selective oxidation reaction. Treatment of MnO2 molecular sieves with RuCl3 in aqueous formaldehyde solution gives a new type of RuO2-supported Mn3O4 catalyst. Detailed catalyst characterization using powder X-ray diffraction, N2 adsorption, scanning and transmission electron microscopes, diffuse reflectance UV-visible spectrometer, and X-ray photoelectron spectroscopy proves that the RuO2 species are dispersed on the highly crystalline Mn3O4 surface. This catalytic conversion process involves molecular oxygen or air (flow, 10 mL/min) as an oxidant. No external oxidizing reagent, additive, or cocatalyst is required to carry out this transformation. This oxidation protocol affords 2,5-diformylfuran, 2-formylfuran, and other aromatic and aliphatic aldehydes in good to excellent yield (70-99%). Moreover, the catalyst is easily recycled and reused without any loss in the catalytic activity.

Alkaline Ionic Liquid Modified Pd/C Catalyst as an Efficient Catalyst for Oxidation of 5-Hydroxymethylfurfural

Conversion of HMF into FDCA was carried out by a simple and green process based on alkaline ionic liquid (IL) modified Pd/C catalyst (Pd/C-OH−). Alkaline ionic liquids were chosen to optimize Pd/C catalyst for special hydrophilicity and hydrophobicity, redox stability, and unique dissolving abilities for polar compounds. The Pd/C-OH− catalyst was successfully prepared and characterized by SEM, XRD, TG, FT-IR, and CO2-TPD technologies. Loading of alkaline ionic liquid on the surface of Pd/C was 2.54 mmol·g−1. The catalyst showed excellent catalytic activity in the HMF oxidation after optimization of reaction temperature, reaction time, catalyst amount, and solvent. Supported alkaline ionic liquid (IL) could be a substitute and promotion for homogeneous base (NaOH). Under optimal reaction conditions, high HMF conversion of 100% and FDCA yield of 82.39% were achieved over Pd/C-OH− catalyst in water at 373 K for 24 h.

One-pot tandem conversion of monosaccharides and disaccharides to 2,5-diformylfuran using a Ru nanoparticle-supported H-beta catalyst

Using a one-pot tandem approach, 2,5-diformylfuran is successfully synthesized in high yields from fructose, glucose and sucrose.

Catalytic oxidation of carbohydrates into organic acids and furan chemicals

A review on the development of new routes for the production of organic acids and furan compoundsviacatalytic oxidation reactions.

Functionalised heterogeneous catalysts for sustainable biomass valorisation

Functionalised heterogeneous catalysts show great potentials for efficient valorisation of renewable biomass to value-added chemicals and high-energy density fuels.

Oxidation of 5-Chloromethylfurfural (CMF) to 2,5-Diformylfuran (DFF)

2,5-Diformylfuran (DFF) is an important biorenewable building block, namely for the manufacture of new polymers that may replace existing materials derived from limited fossil fuel resources. The current reported methods for the preparation of DFF are mainly derived from the oxidation of 5-hydroxymethylfurfural (HMF) and, to a lesser extent, directly from fructose. 5-Chloromethylfurfural (CMF) has been considered an alternative to HMF as an intermediate building block due to its advantages regarding stability, polarity, and availability from glucose and cellulose. The only reported method for the transformation of CMF to DFF is restricted to the use of DMSO as the solvent and oxidant. We envisioned that the transformation could be performed using more attractive conditions. To that end, we explored the oxidation of CMF to DFF by screening several oxidants such as H₂O₂, oxone, and pyridine N-oxide (PNO); different heating methods, namely thermal and microwave irradiation (MWI); and also flow conditions. The combination of PNO (4 equiv.) and Cu(OTf)₂ (0.5 equiv.) in acetonitrile was identified as the best system, which lead to the formation of DFF in 54% yield under MWI for 5 min at 160 °C. Consequently, a range of different heterogeneous copper catalysts were tested, which allowed for catalyst reuse. Similar results were also observed under flow conditions using copper immobilized on silica under thermal heating at 160 °C for a residence time of 2.7 min. Finally, HMF and 5,5'-oxybis(5-methylene-2-furaldehyde) (OBMF) were the only byproducts identified under the reaction conditions studied.

Direct Transformation of HMF into 2,5-Diformylfuran and 2,5-Dihydroxymethylfuran without an External Oxidant or Reductant

The selective transformation of 5-hydroxymethylfurfural (HMF) to valuable 2,5-diformylfuran (DFF) and 2,5-dihydroxymethylfuran (DHMF) is highly desirable but remains a great challenge owing to its tendency to over-oxidation and over-reduction. In this work, HMF is directly converted into DFF and DHMF without external oxidant or reductant through a Meerwein-Ponndorf-Verley-Oppenauer (MPVO) reaction. In such a MPVO process, HMF is used as both oxidant and reductant and DFF and DHMF are simultaneously produced with a 1:1 molar ratio in the presence of a Lewis acid catalyst. Under high initial HMF concentration, a HMF conversion of up to 44.7 % can be reached within 1 h. Moreover, this atom-efficient transformation route for HMF also provides a promising protocol for the crude separation of DHMF products from DFF products, owing to the lower solubility of DHMF compared to DFF in acetonitrile.

Direct synthesis of V-containing all-silica beta-zeolite for efficient one-pot, one-step conversion of carbohydrates into 2,5-diformylfuran

V-containing all silica beta-zeolite exhibited high atom-efficiency in the direct synthesis of 2,5-diformylfuran from carbohydrates.

Nanobelt α-CuV2O6 with hydrophilic mesoporous poly(ionic liquid): a binary catalyst for synthesis of 2,5-diformylfuran from fructose

The task-specific binary catalyst composed of nanobelt α-CuV₂O₆ and hydrophilic mesoporous poly(ionic liquid) exhibited high efficiency and stable activity in the direct synthesis of 2,5-diformylfuran (DFF) from fructose.

One-Pot Template-Free Synthesis of Cu-MOR Zeolite toward Efficient Catalyst Support for Aerobic Oxidation of 5-Hydroxymethylfurfural under Ambient Pressure

Supported catalysts are widely studied, and exploring new promising supports is significant to access more applications. In this work, novel copper-containing MOR-type zeolites Cu-MOR were synthesized in a one-pot template-free route and served as efficient supports for vanadium oxide. In the heterogeneous oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-diformylfuran (DFF) with molecular oxygen (O2) under ambient pressure, the obtained catalyst demonstrated high yield (91.5%) and good reusability. Even under the ambient air pressure, it gave a DFF yield of 72.1%. Structure-activity relationship analysis indicated that the strong interaction between the framework Cu species and the guest V sites accounted for the remarkable performance. This work reveals that the Cu-MOR zeolite uniquely acts as the robust support toward well-performed non-noble metal heterogeneous catalyst for biomass conversion.

One-Pot Conversion of Carbohydrates into Furan Derivatives via Furfural and 5-Hydroxylmethylfurfural as Intermediates

Recently, there has been growing interest in the transformation of renewable biomass into value-added fuels and chemicals. The catalytic conversion of naturally abundant carbohydrates can generate two-important furan chemicals: 5-hydroxymethylfurfural (HMF) from C6 carbohydrates and furfural from C5 carbohydrates. Both HMF and furfural have received great interest as precursors in the synthesis of commodity chemicals and liquid fuels. In recent years, a trend has emerged to integrate sequential catalytic processes involving multistep reactions for the direct one-pot transformation of carbohydrates into the aimed fuels and chemicals. One-pot reactions have remarkably unique and environmentally friendly benefits, including the fact that isolation and purification of intermediate compounds can be avoided. Herein, the present article aims to review recent advances in the one-pot conversion of carbohydrates into furan derivatives via furfural and HMF as intermediates. Special attention will be paid to the catalytic systems, mechanistic insight, reaction pathways, and catalyst stability. It is expected that this review will guide researchers to develop effective catalytic systems for the one-pot transformation of carbohydrates into furan derivatives.