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Electrocatalytic conversion of biomass‐derived 5‐hydroxymethylfurfural (HMF) to value‐added 2,5‐furandicarboxylic acid (FDCA) is of great significance in compensating for the rapid consumption of fossil resources. However, it is a challenge to further improve the performance of HMF electrocatalytic oxidation (HMFOR) by synergistic kinetics (active sites) and thermodynamics (adsorption sites). In this work, Al(OH)3/Co(OH)2 is successfully fabricated as an efficient catalyst, and its catalytic mechanism for HMF oxidation is clarified. Extended X‐ray absorption fine structure (EXAFS) analysis demonstrate that electrochemically generated Co3+ is the main catalytic site for HMF oxidation. The HMF equilibrium adsorption capacity of Al(OH)3 reach 57.0 mg g−1, which effectively increase the initial concentration of substrate and promoted the reaction rate. The combined results, based on 24 stable cycles and an FDCA yield retention rate of 98.6% after 180 days, are the highest ever achieved. Additionally, it is shown that this system can oxidize four other biomass‐derived substrates. Therefore, this work provides insight into a hydroxide catalyst that owes its efficiency to synergy between active and adsorption sites. [ABSTRACT FROM AUTHOR]

2,5‐Furandicarboxylic acid (FDCA) is a biomass‐derived monomer for the production of poly(ethylene 2,5‐furandicarboxylate) (PEF), which is a novel polyester that can serve as a sustainable alternative to traditional petroleum‐based poly(ethylene terephthalate) (PET). Currently, the industrial production of FDCA depends on the thermo catalytic aerobic oxidation of 5‐hydroxymethylfurfural (HMF) using heterogeneous catalysts in aqueous solution, in which process equivalent homogeneous bases are usually needed to promote the oxidation of hydroxymethyl and aldehyde groups and simultaneously improve the solubility of oxidative products via forming carboxylate. The involvement of massive base causes risks of equipment corrosion and necessitates subsequent product separation and purification with a large amount acid. In this context, the base‐free aerobic oxidation of HMF to FDCA has attracted much concern. Nowadays, by developing supported catalysts with multiple catalytic sites, using diluted substrate and finding good solvent for FDCA, much progress has been achieved in this field. This review provides the state of the art of the heterogeneous catalysis for aerobic oxidation of HMF to FDCA under base‐free conditions, highlighting the catalytic mechanism to shed light on the catalyst design principles. [ABSTRACT FROM AUTHOR]

A series of CuCo bimetallic catalysts were prepared via the co‐precipitation method for the catalytic transformation of biomass‐derived 5‐hydroxymethylfurfural (HMF) into 2,5‐furandicarboxylic acid (FDCA). FDCA acts as a precursor for biodegradable biopolymer polyethylene furanoate production, thereby achieving a carbon‐neutral approach. Out of all the synthesized catalysts, CuCo(1 : 1) showed remarkable catalytic activity and yielded 70.67 % FDCA while achieving 100 % HMF conversion in 5 minutes at 50 °C temperature in the presence of tert‐butyl hydroperoxide as an oxidant. Synergistic effects of the catalyst, such as adsorbed oxygen, relative oxygen vacancy, lesser pore size, and pore volume, were key factors attributed to the catalyst's excellent activity. The synthesized catalyst showed good recyclability with a minimal decrease in FDCA yield up to 5 cycles. Pre and post‐characterization of catalysts such as BET, TEM, FE‐SEM, XRD, H2‐TPR, CO2 TPD, ICP‐OES, and XPS were done to correlate the catalyst's properties with its activity. In addition, the effect of reaction parameters such as stirring speed, temperature reaction time, catalyst weight, base, and oxidant were studied to achieve optimum reaction conditions. The reaction products were analyzed quantitatively and qualitatively using HPLC and HR‐MS. [ABSTRACT FROM AUTHOR]

The present study reports the synthesis, characterization, and application of NiCo bimetallic catalysts to produce 2,5‐furandicarboxylic acid (FDCA) via the oxidation of bio‐renewable 5‐hydroxymethylfurfural (HMF). FDCA is a biopolymer precursor and a potential replacement for terephthalic acid (TPA). The catalysts were synthesized via the co‐precipitation method in different molar ratios of NiCo, followed by calcination in a muffle furnace. As a result, the complete conversion of HMF and a maximum 84.89 % FDCA yield was measured at 50 °C in 50 minutes in the presence of NiCo(3 : 1) catalyst. In addition, effect reaction parameters, including catalyst amount, temperature, time, base, and oxidant amount on the FDCA yield, were studied, and the process was optimized. The NiCo(3 : 1) catalyst showed a negligible loss in activity for at least five cycles. The higher catalytic activity and stability are attributed to the synergistic effect of bimetallic catalysts, such as higher lattice oxygen. Accordingly, the catalyst was characterized using BET, XRD, H2‐TPR, CO2‐TPD, HR‐TEM, and XPS to correlate their properties and activity. The reaction products were analyzed quantitatively using HPLC and qualitatively using HR‐MS. [ABSTRACT FROM AUTHOR]

The utilization of biomass-derived compounds to produce abundant renewable bio-based chemicals has attract intense interest. The catalyzed oxidation of 5-hydroxymethylfurfural (HMF) is an useful strategy to produce value-added compounds, such as 2, 5-diformylfuran (DFF) and 2,5-furandicarboxylic acid (FDCA). The Co-MnO2 was developed as an efficient catalyst in HMF conversion under mild conditions. Solvents were investigated and play a vital role on the products distribution. The formation of DFF is facilitated in the organic solvent and 2,5-furandicarboxylic acid (FDCA) is favored to generate in H2O. As a result, a 87% conversion of HMF with 87% selectivity of DFF was detected in isopropanol, while a 95% FDCA selectivity at 93% HMF conversion was measured in H2O. Besides, organic solvents were found to affect the HMF selective oxidation reaction and base additives effect on the promotion of C-H and O–H bones activation in HMF molecule was also discussed. This work provide a tunable oxidation process in the transformation of HMF. The tunable oxidation of 5-hydroxymethylfurfural to 2,5-diformylfuran (DFF) and 2,5-furandicarboxylicacid (FDCA) has been successfully performed with Co-MnO2 catalyst. [ABSTRACT FROM AUTHOR]

Furanoate polyesters are an extremely promising new class of materials for packaging applications, particularly furanoate-based nanocomposites, which have gained a high interest level in research and development in both academia and industries. The monomers utilised for the synthesis of furanoate-based polyesters were derived from lignocellulosic biomass, which is essential for both eco-friendliness and sustainability. Also, these polyesters have a lower carbon footprint compared to fossil-based plastics, contributing to greenhouse gas reduction. The furanoate-based nanocomposites exhibit enhanced performance characteristics, such as high thermal stability, excellent mechanical strength, superior barrier resistance, and good bacteriostatic rate, making them suitable for a wide range of industrial applications, especially for food-packaging applications. This paper reviews the recent trends in the synthesis routes of monomers, such as the various catalytic activities involved in the oxidation of 5(hydroxymethyl)furfural (HMF) into 2,5-furandicarboxylic acid (FDCA) and its ester, dimethyl furan-2,5-dicarboxylate (DMFD). In addition, this review explores the fabrication of different furanoate-based nanocomposites prepared by in situ polymerization, by melt mixing or solvent evaporation methods, and by using different types of nanoparticles to enhance the overall material properties of the resulting nanocomposites. Emphasis was given to presenting the effect of these nanoparticles on the furanoate polyester's properties. [ABSTRACT FROM AUTHOR]

The exploitation of bio‐based materials derived from renewable resources represents a pivotal strategic approach in addressing environmental pollution and alleviating the scarcity of fossil resources. 2,5‐Furandicarboxylic acid (FDCA) is the most potential substitute for terephthalic acid. Lignin is the most abundant aromatic biomass resource. However, the preparation of high‐performance lignin/FDCA‐based bio‐polyesters remains a formidable challenge. Herein, a multifunctional lignin‐modified polyester elastomer (LFPEe) is designed using FDCA‐based polyester oligomer (PPeF) and lignin (AOH) as building blocks. The LFPEe exhibits superior mechanical properties with the optimum tensile strength, fracture strain, and elastic recovery ratio up to 58.9 MPa, 610% and 88.9%, respectively, attributing to the formation of dual cross‐linking network with nanophase separation structure. Furthermore, leveraging the inherent characteristics of lignin, the LFPEe demonstrates excellent light‐controlled shape memory and excellent UV shielding performance. This innovative work not only breaks the performance dependence of FDCA‐based polyester on high molecular weight but also highlights a novel paradigm for value‐added utilization of lignin in sustainable bio‐polyesters. [ABSTRACT FROM AUTHOR]

As a result of hydrothermal synthesis of 2,5-furandicarboxylate (fdc2−), Cd(II) ion and bis(imidazole) derivative 1,4-bis(1H-imidazole-1-yl)butane (bib) ligand, a novel two-dimensional Cd(II) coordination polymer {[Cd(µ-fdc)(H2O)(µ-bib)]·H2O}n (1) was synthesized. According to the results of single crystal X-ray diffraction analysis, the complex was crystallized in the monoclinic system and in the P21/n space group. In addition, the thermal, luminescence and optical properties of the complex were investigated. The complex emits a maximum at 509 nm and also shows semi-conductor properties according to the solid-state UV–Vis diffuse reflection spectra results. To determine chemical structure, vibrational properties and some chemical properties of complex, theoretical calculations were carried out. All theoretical computations were performed using the DFT method at the B3LYP/LanL2DZ level of theory. The obtained experimental results were in good agreement with theoretical results. To calculate HOMO–LUMO energy values, which provided insights into the material's electronic properties, DFT calculations were used. Detailed information about the local and global chemical activity, as well as the electrophilic and nucleophilic nature of the complex, were also obtained. [ABSTRACT FROM AUTHOR]

FDCA (2,5-furandicarboxylic acid), produced by oxidizing carbohydrate-derived HMF (5-hydroxymethylfurfural), is a valuable monomer for biopolymers. The difference in the solvent system between the dehydration reaction and oxidation reactions seriously affects the process continuity and production efficiency. Herein, we reported a cascade process for FDCA production from carbohydrates in a single acetic acid system. The fructose conversion was complete and total furan compounds yield reached nearly 90%, which contained 42.8% HMF and 47.1% 5-acetoxymethylfurfural (AMF) in the acetic acid system with NaBr addition. After the azeotropic distillation and vacuum distillation in situ, AMF, a more stable intermediate than HMF, could be easily collected with 90.5% recovery and 99.9% purity. AMF was also oxidized into FDCA with 91.1% yield by Co/Mn/Br catalysts in the acetic acid system. Finally, the cascade process, including fructose dehydration–esterification and HMF/AMF mixture oxidation, was successfully realized in a single acetic acid system. This process is simple to operate, easy to implement, eliminates the use of extra acid or self-made catalysts and expensive solvents, and has the potential for continuous preparation from carbohydrates to FDCA. [ABSTRACT FROM AUTHOR]

In this work, a simple hydrothermal synthesis method is used to prepare photocatalytic NiO/WO 3 -biochar composite material, which is applied to catalyze the one-step conversion of 5-hydroxymethylfurfural to 2,5-furandicarboxylic acid with synergistic hydrogen production. The optoelectronic properties of NiO/WO 3 -biochar composite material are characterized. The results indicate that the p-n heterojunction-coupled biochar structure between NiO and WO 3 in the NiO/WO 3 -biochar composite is an important prerequisite for ensuring the one-step oxidation reaction of 5-hydroxymethylfurfural. The experimental results reveal the possible reaction pathways. Under the optimal ratio of NiO/WO 3 -biochar composite material, the 5-hydroxymethylfurfural conversion rate reaches 100%, the 2,5-furandicarboxylic acid yield reaches 99.6%, and the Faraday efficiency of hydrogen evolution is 98%. This study provides a new approach for the one-step photocatalytic synthesis of 2,5-furandicarboxylic acid from 5-hydroxymethylfurfural, as well as a novel and efficient catalyst for photocatalytic oxidation technology. [Display omitted] • NiO/WO 3 -biochar composite is successfully prepared. • Mechanism of hydrogen production by photocatalytic reaction of straw is analyzed. • HMF undergoes photocatalytic one-step oxidation to FDCA with 99.6% efficiency. [ABSTRACT FROM AUTHOR]

The catalytic oxidation of 5‐hydroxymethylfurfural (HMF) is an important process for producing a renewable furan‐2,5‐dicarboxylic acid (FDCA). Although several Pt‐based catalysts have been reported to efficiently catalyze the oxidation of HMF, the functional roles of catalyst supports, as corroborated by spectroscopic techniques, have not been fully described. Here, we report on Pt nanoparticles supported on metal‐organic frameworks (MOFs) that catalyze the oxidation of HMF to FDCA in the absence of base. Several catalysts are prepared by immobilizing pre‐synthesized Pt nanoparticles on supports, allowing for the investigation of the role of the supports without the influence of the size of Pt nanoparticles (Pt NPs). By analyzing the catalytic performances along with the electronic properties using X‐ray photoelectron spectroscopy and surface properties of the catalysts using in situ infrared spectroscopy of adsorbed CO2, we find that the presence of Pt NPs in the metallic phase and basic hydroxyl groups on the support promote the HMF oxidation. [ABSTRACT FROM AUTHOR]

Noble metal‐free catalyst or catalytic oxidation of 5‐hydroxymethylfurfural into 2,5‐furandicarboxylic acid are proposed in this study as a proposal to solve one of the great disadvantages of this reaction of using preferably noble metal‐based catalysts. The catalytic activity of six MnO2 crystal structures is studied as alternative. The obtained results showed a strong connection between catalytic activity the type of MnO2 structure organization and redox behavior. Among all tested catalysts, ϵ‐MnO2 showed the best performance with an excellent yield of 74 % of 2,5‐furandicarboxylic acid at full ‐hydroxymethylfurfural conversion. [ABSTRACT FROM AUTHOR]

Effective structural design can make the catalyst have higher specific surface area and dispersed active sites, thus endowing the catalyst higher catalytic efficiency. In this work, magnetic nitrogen-doped carbon nanotube (CNT) was introduced as the support to immobilize the zirconium-based biomass-derived hybrid (Zr-FDCA) through solvothermal method, in which specific surface area had significantly increased to improve the dispersibility of zirconium, thus improving the adsorption over the catalyst to ethyl levulinate (EL). In addition, the introduced nitrogen served as the basic sites to boost the proton transfer in catalytic transfer hydrogenation (CTH) reaction. As a result, the prepared Zr-FDCA@CNT exhibited an ideal catalytic performance in CTH of EL into γ-valerolactone. Gratifyingly, Zr-FDCA@CNT also showed magnetism and good reusability, which could be easily separated from the reaction mixture and no significant loss in the activity after reuse for four runs. [ABSTRACT FROM AUTHOR]

The production of 2,5-furandicarboxylic acid (FDCA) through green reaction routes is of crucial scientific value for the production of sustainable polymers. This study explores the active centers in cobalt-nitrogen-doped carbon (Co-N/C) for FDCA production. It was established that Co-Nx synergistically along with the nitrogen-doped carbon acted as centers for 5-hydroxymethylfurfural (HMF) oxidation. This study demonstrates a sustainable method for FDCA production from HMF without using precious metals, organic solvents, and harsh basic environments. Co-N/C catalyst displayed a high FDCA yield of ∼90% in an aqueous medium under mildly basic conditions in 34 h with 100% HMF conversion. An innovative strategy of stepwise base addition has been proposed to effectively accelerate the generation reaction of FDCA. The detrimental effects of high heating rate and calcination temperature on the active centers were also thoroughly investigated. Through DFT simulations it was established that Co-Nx aided in the activation of oxygen for HMF oxidation.

The selective electrooxidation of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA) is of great significance in replacing terephthalic acid for the production of high-performance polymeric materials. This necessitates the development of advanced electrocatalysts. Ni-based nanomaterials, known for their unique electronic structure and high intrinsic activity, show great promise for the selective electrooxidation of HMF to FDCA. To provide guidance for the further development of advanced HMF electrocatalysts, we present a comprehensive review of recent progress in this field, focusing on HMFOR mechanisms, effective engineering strategies (e.g., morphology design, defect engineering, interface engineering, and strain engineering) for improving electrocatalytic performance, and representative Ni-based catalysts used for HMFOR. Finally, we offer a conclusion and highlight the challenging issues that need to be addressed, providing researchers with direction for future endeavors. • A review on the oxidation of HMF into FDCA catalyzed by Ni-based materials is summarized. • The mechanisms of HMF electrooxidation are described thoroughly. • Strategies for optimizing the catalytic performance of Ni-based materials for HMFOR are mentioned. • Recent progresses, challenges, and perspectives are highlighted. [ABSTRACT FROM AUTHOR]

A green and sustainable --COOH & --OH condensation solution polymerization method was hereby reported for FDCA-based polyesters to avoid discoloration and toxic solvents. First, taking poly(ethylene 2,5-furandicarboxylate) (PEF) as the representative of FDCA-based polyester, enabling good white appearance PEF with Mn=6.51x10³ gmol-1 from FDCA and ethylene glycol in green solvent γ-valerolactone (GVL), catalyzed by 4-dimethylaminopyridine (DMAP) and N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride (EDC). Additionally, the molecular weight of PEF was rapidly improved (Mn >2.5x104 gmol-1) via remelting polycondensation within minutes, with the dispersity still kept relatively low dispersity (Đ<1.40). Importantly, the --COOH & --OH condensation solution polymerization method was successfully applied for the synthesis of various FDCA-based polyesters, including diols with varying carbon chain lengths (3 to 11 carbons) and cycloalkyl diols, especially the applicability of this method to diols containing C=C double bonds, which was found to exhibit low heat resistance. Lastly, assisting with 13C labeled 1,4-succinic acid and in-situ 13C-NMR, an in-depth study of the possible catalytic mechanism was proposed, by which, EDC activated FDCA, and then DMAP catalyzed it with diol to yield macromolecular chain of polyester. Overall, the results provided a green and sustainable strategy for the synthesis of FDCA-based polyesters. [ABSTRACT FROM AUTHOR]

5‐(Hydroxymethyl)furfural (HMF) is a key platform chemical derived from renewable biomass sources, holding great potential as starting material for the synthesis of valuable compounds, thereby replacing petrochemical‐derived counterparts. Among these valorised compounds, 2,5‐furandicarboxylic acid (FDCA) has emerged as a versatile building block. Here we demonstrate the biocatalytic synthesis of FDCA from HMF via a one‐pot three‐step oxidative cascade performed via two operative steps under mild reaction conditions employing two unspecific peroxygenases (UPOs) using hydrogen peroxide as the only oxidant. The challenge of HMF oxidation by UPOs is the chemoselectivity of the first step, as one of the two possible oxidation products is only a poor substrate for further oxidation. The unspecific peroxygenase from Marasmius oreades (MorUPO) was found to oxidize 100 mM of HMF to 5‐formyl‐2‐furoic acid (FFCA) with 95 % chemoselectivity. In the sequential one‐pot cascade employing MorUPO (TON up to 13535) and the UPO from Agrocybe aegerita (AaeUPO, TON up to 7079), 100 mM of HMF were oxidized to FDCA reaching up to 99 % conversion and yielding 861 mg isolated pure crystalline FDCA, presenting the first example of a gram scale biocatalytic synthesis of FDCA involving UPOs. [ABSTRACT FROM AUTHOR]

A Ni(II) complex, [Ni2(FDC)2(4,4′-BMIBP)2(H2O)2·3H2O]n (1) (4,4′-BMIBP = 4,4'-bis(2-methyl-imidazolyl)biphenyl, H2FDC = 2,5-furandicarboxylic acid) was hydrothermally synthesized and structurally characterized. Complex 1 possesses a polycatenated architecture based on an undulated (4,4)-sql layer. Complex 1 can be used for the selective detection of nitrofurantoin (NFT) in aqueous solutions. The luminescence quenching mechanism of complex 1 is attributed to the competitive absorption. [ABSTRACT FROM AUTHOR]

Poly[(3‐hydroxybutyrate)‐co‐(4‐hydroxybutyrate)] (P34HB), poly[(butylene succinate)‐co‐(butylene furandicarboxylate)] (PBSF) and poly(vinyl acetate) (PVAc) were melt‐blended to prepare P34HB/PBSF/PVAc blends with improved ductility. The thermal properties, mechanical properties, rheological properties and morphology of the blends were systematically studied. The addition of PBSF promoted the melt crystallization of P34HB. The temperatures at 5% weight loss of the blends were higher than that of P34HB. The surface of the blends was investigated using scanning electron microscopy. The surface of P34HB was very smooth, but the surfaces of the blends were rough. PVAc can increase the compatibility between P34HB and PBSF. Compared with P34HB, the elongation at break of the blends was increased to 219.1%. © 2024 Society of Industrial Chemistry. [ABSTRACT FROM AUTHOR]

The design of high activity catalyst for the efficiently conversion of 5‐hydroxymethylfurfural (HMF) to 2,5‐furandicarboxylic acid (FDCA) gains great interest. The rationally tailoring of electronic structure directly affects the interaction between catalysts and organic substrates, especially molecular oxygen as the oxidant. This work, the bimetallic catalysts AuPd/CeO2 were prepared by the combining method of chemical reduction and photo‐deposition, effectively concerting charge between Au and Pd and forming the electron‐rich state of Au. The increasing of oxygen vacancy concentration of CeO2 by acidic treatment can facilitate the adsorption of HMF for catalysts and enhance the yield of FDCA (99.0 %). Moreover, a series of experiment results combining with density functional theory calculation illustrated that the oxidation performance of catalyst in HMF conversion was strongly related to the electronic state of interfacial Au−Pd−CeO2. Furthermore, the electron‐rich state sites strengthen the adsorption and activation of molecular oxygen, greatly promoting the elimination of β‐hydride for the selective oxidation of 5‐hydroxymethyl‐2‐furancarboxylic acid (HMFCA) to FDCA, accompanied with an outgoing FDCA formation rate of 13.21 mmol ⋅ g−1 ⋅ min−1 at 80 °C. The perception exhibited in this research could be benefit to understanding the effects of electronic state for interfacial sites and designing excellent catalysts for the oxidation of HMF. [ABSTRACT FROM AUTHOR]

This article presents partially bio‐based unsaturated polyester resins (UPR) based on 2,5‐furandicarboxylic acid (FDCA). Three different FDCA‐based resins are prepared, which are potentially suited as i) general purpose resin (composed of 1,2‐propylene glycol), ii) resin for pultrusion (composed of diethylene glycol and 1,2‐propylene glycol), and iii) resin for pipe liners (composed of neopentyl glycol and 1,2‐propylene glycol). The mechanical and thermal properties of the bio‐based UPR are systematically investigated and compared with analogous fossil‐based UPR composed of phthalic and isophthalic acid, signaling comparable or even better properties for the bio‐based resins depending on the application targeted. [ABSTRACT FROM AUTHOR]

Unsaturated polyester resins, one of the most important thermosets, are invariably produced from oil-based monomers. Their application is limited in areas where high thermal stability is required due to their low Tg. Besides, these resins contain 30–40% hazardous styrene as a reactive solvent. Therefore, developing bio-based solventless unsaturated polyester resin with medium to high thermomechanical properties compared to petrochemical-based counterparts is important. In order to achieve this, a series of branched bio-based unsaturated polyester resins were synthesized using bulk polymerization method in two steps. In the first step, four different intermediates were prepared by reacting glycerol (as a core molecule) with either isosorbide (diol), 1,3-propanediol (diol), 2,5-furandicarboxylic acid (saturated diacid), or adipic acid (saturated diacid). In the second step, the branched intermediate was end capped with methacrylic anhydride to introduce reactive sites for cross-linking on the branch ends. The chemical structure of the resins was characterized by 13C-NMR. FT-IR confirmed the polycondensation reaction in the first step and the end functionalization of the resins with methacrylic anhydride in the second step. The effect of 2,5-furandicarboxylic acid and isosorbide on thermomechanical and thermal properties was investigated using dynamic mechanical analysis, differential scanning calorimetry, and thermo-gravimetric analysis. Results indicated that 2,5-furandicarboxylic acid based resins had superior thermomechanical properties compared to a commercial reference unsaturated polyester resin, making them promising resins for high-temperature composite applications. For example, the resin based on 2,5-furandicarboxylic acid and isosorbide and the resin based on 2,5-furandicarboxylic acid and 1,3-propanediol gave glass transition temperatures of 173 °C and 148 °C, respectively. Although the synthesized 2,5-furandicarboxylic acid based resins had higher viscosity (22.7 Pas) than conventional unsaturated polyester (0.4–0.5 Pas) at room temperature, preheated resins can be used for making high-temperature-tolerance fiber-reinforced composite. [ABSTRACT FROM AUTHOR]

The electrooxidation of 5-hydroxymethylfurfural (HMF) provides a prospective method to produce high-value 2,5-furandicarboxylic acid (FDCA). Since this multistep process includes the oxidation of aldehyde and hydroxyl groups, a deep understanding of the mechanism of HMF oxidation reaction (HMFOR) is crucial. Herein, the surface reconstruction of the nickel-based catalyst is regulated by Co and V2O3 modifications to reveal the relationship between the reconstructed surface and the HMFOR performance. The introduction of the V2O3 nanosheet facilitates the in situ reconstruction of the nickel-based nanocatalyst by enhancing the adsorption of OH*. The incorporation of Co adjusts the electronic structure of nickel, contributing to a decrease in the formation potential of NiOOH. Moreover, the insitugenerated NiOOH promotes the adsorption and activation of aldehyde and hydroxyl groups, providing beneficial effects for HMFOR. Impressively, Co–Ni/V2O3/NF needs only 1.29 VRHE to achieve 10 mA cm–2 for HMFOR and maintains high FDCA selectivity for 10 cycles. This work explains the regulations of V2O3 and Co on NiOOH species formation, which is conducive to designing an efficient nickel-based catalyst for HMF oxidation. [ABSTRACT FROM AUTHOR]

BACKGROUND: Photothermal catalytic oxidation technology for synthesis of high value‐added chemicals has become a hot topic of research at home and abroad. As a special structure, titania (TiO2) nanotubes (Ti‐NTs) possess larger specific surface area and adsorption capacity, which have shown great application prospects in photothermal catalytic oxidation. RESULTS: In this work, high‐performance palladium (Pd‐Ti‐NTs catalyst were prepared and applied to the photothermal catalytic oxidation of 5‐hydroxymethyl (HMF) and benzyl alcohol. The photothermal dependence on catalytic activity and selectivity of HMF and benzyl alcohol oxidation was studied in detail. The results revealed that compared with thermal catalytic oxidation, the catalysts showed significantly higher conversions of both benzyl alcohol and HMF under light. in particular, HMF conversion increase from 55.6% to 99.7%. Aldehyde oxidation is inhibited by alcohol and can be dramatically promoted by light radiation. This is probably because alcohol can inhibit the adsorption of aldehyde, and this inhibiting effect is weakened through light radiation, thus promoting the oxidation of aldehydes. Therefore, the selectivity of the final products 2,5‐furandicarboxylic acid (FDCA) and benzoic acid were dramatically increased in both systems under light radiation, and the selectivity for FDCA was obviously increased from 5.8% to 61.3%, and the yield reached 61.0%, which is higher than that of most of the reported Pd‐TiO2‐based catalysts for FDCA. CONCLUSIONS: In this paper, we verify that Pd‐Ti‐NTs could preferentially promote the conversion of aldehydes to acids in the presence of light, and obtained catalysts with high catalytic performance and high stability for benzyl alcohol and HMF oxidation. © 2024 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

The platform molecule 2,5-furandicarboxylic acid (FDCA) has potential applications. FDCA can be synthesized through the oxidation of 5-hydroxymethylfurfural (HMF). In this study, HMF oxidation to FDCA was conducted over ZSM-5-based catalysts from natural sources. ZSM-5 was impregnated with CuO and NiO oxide metals to increase their acidity and oxidizing ability. Characterization of the catalyst utilizing x-ray diffraction (XRD), infrared spectrophotometer (FT-IR), scanning electron microscopy-energy dispersive x-ray (SEM-EDX), Brunauer-Emmet-Teller (BET) surface area analysis, and temperature-programmed desorption of ammonia (NH3-TPD) led to the discovery of its physicochemical characteristics. The results showed that synthesized ZSM-5 had hierarchical pores with a surface area of 123.58 m2/g. Impregnation with CuO and NiO increased the acidity by 22.5 and 3.04 % for CuO/ZSM-5 and NiO/ZSM-5, respectively. In a small glass batch reactor, HMF was converted to FDCA, and the products were analyzed using High-Performance Liquid Chromatography (HPLC) to determine the yield of FDCA and the intermediate compounds, such as 5-hydroxymethylfuroic acid (HMFCA), 5-formylfuroic acid (FFCA), and 2,5-diformylfuran (DFF). HPLC results showed no DFF signal, indicating the formation of FDCA from HMF through HMFCA and FFCA. The highest conversion (99.2 %) was obtained using a NiO/ZSM-5 catalyst at a temperature of 130 °C for 4 h, with FDCA yield of 88.9 %.

Bio-based and biodegradable materials have received special interests in recent years as a replacement for petroleum-based plastics. Poly(vinyl alcohol) (PVA), cellulose nanofiber (CNF), and 2,5-furandicarboxylic acid (FDCA) are typical examples among these environmentally friendly molecules. In this study, we investigated the synergistic effects of CNF reinforcement and crosslinking with FDCA on the properties of PVA. The composite films were prepared via a straightforward mechanical-dispersion method, wherein CNF was incorporated into a PVA solution and subsequently crosslinked with FDCA. Comprehensive characterizations, including Attenuated Total Reflection-Fourier Transform Infrared Spectroscopy (ATR-IR), X-ray diffraction (XRD), Thermal Gravimetric Analysis/Differential Thermal Gravimetric Analysis (TGA/DTGA), Differential Scanning Calorimetry (DSC), tensile testing, and morphological studies, were performed to assess the impact of these modifications. Our findings revealed significant enhancements in the mechanical and thermal properties of the composites. Notably, the tensile strength of the PVA-c-FDCA/CNF composite with 2% CNF reached 37.08 MPa, representing a twofold increase compared to both crosslinked PVA (16.84 MPa) and unmodified PVA (14.57 MPa). TGA/DTGA analysis demonstrated improved thermal stability, with the degradation temperature reaching 371°C, compared to the 298°C observed for PVA. DSC and XRD results indicated a reduction in PVA crystallinity after crosslinking and blending with CNF. Scanning electron microscopy (SEM) images showed good compatibility between PVA and CNF. This study underscores the potential of CNF reinforcement and FDCA crosslinking as a viable strategy to enhance the mechanical properties of PVA-based materials. [ABSTRACT FROM AUTHOR]

Cutin, one of the main structural components of tomato peels, is a waxy biopolymer rich in hydroxylated fatty acids. In this study, 10,16-dihydroxyhexadecanoic acid (10,16-diHHDA) was extracted and isolated from tomato peels and exploited to develop fully crosslinked polyesters as potential candidates for replacing fossil-based metal protective coatings. A preliminary screening was conducted to select the base formulation, and then a design of experiments (DoE) was used as a methodology to identify the optimal composition to develop a suitable coating material. Different formulations containing 10,16-diHHDA and other biorefinery monomers, including 2,5-furandicarboxylic acid, were considered. To this end, all polyesters were characterized through differential scanning calorimetry (DSC) and gel content measurements to determine their Tg value and crosslinking efficiency. Compositions exhibiting the best trade-off between Tg value, chemical resistance, and sufficiently high 10,16-diHHDA content between 39 and 48 wt.% were used to prepare model coatings that were characterized for assessing their wettability, scratch hardness, chemical resistance, and adhesion to metal substrates. These polyester coatings showed a Tg in the range of 45–55 °C, a hydrophobic behavior with a water contact angle of around 100°, a good solvent resistance (>100 MEK double rubs), and an adhesion strength to steel higher than 2 MPa. The results obtained confirmed the potential of cutin-based resins as coatings for metal protection, meeting the requirements for ensuring physicochemical properties of the final product, as well as for optimizing the valorization of such an abundant agri-food waste as tomato peels. [ABSTRACT FROM AUTHOR]

An efficient solvent mediated & use of metal-free catalyst strategy was developed for synthesis of FDCA over two steps. A simple & economical glucose-hydrothermally carbonized (Glu-HTC) catalyst was prepared and evaluated for synthesis of 2,5-Diformyl furan (DFF) from fructose & 5-hydroxymethylfurfural (HMF) in the 1st step. DFF was then converted to FDCA using Pinnick oxidation in the 2nd step. DFF was obtained in 82% & 86% yields from fructose & HMF respectively whereas FDCA was obtained in 94–95% yield from DFF. FDCA was thus formed in an overall yield of 78% and 81% from fructose & HMF respectively. This strategy eliminated use of expensive noble metals for FDCA synthesis and also intermediates such as HMFCA & FFCA were not observed after the reaction as DFF was completely oxidized to FDCA. [ABSTRACT FROM AUTHOR]

5‐hydroxymethylfurfural (HMF) was selectively oxidized to 2,5‐furandicarboxylic acid (FDCA) using an effective catalytic system made of Au particles supported on Ce‐modified MgFe layered double hydroxide. The structural features and performance of the as‐prepared catalysts were examined using a range of characterizations, and the impact of altering reaction parameters was explored. It was demonstrated that the presence and quantity of Ce and Mg species in the catalyst formulation were the primary determinants of the activity of the Au@Mg−N−M−LDH catalysts (M=Ce, Cu, Mn, Zr, and N=Fe, Al). The catalyst Au@MgFeCe−LDH, loaded with 1 wt % Au, exhibited outstanding catalytic activity in the production of FDCA, achieving complete HMF conversion and 90 % FDCA selectivity. This was accomplished through a two‐step heating procedure, involving initial heating of the reaction medium at 40 °C for 2 hours followed by a subsequent heating at 100 °C for 6 hours, conducted under an oxygen pressure of 5 bar. [ABSTRACT FROM AUTHOR]

Methods for the preparation of fluorine-containing polyhydrazides and poly-1,3,4-oxadiazoles based on 2,5-furandicarboxylic acid have been developed. Properties of the resulting polymers were evaluated using GPC, TMA, TGA, and NMR spectroscopy. [ABSTRACT FROM AUTHOR]

Platform chemical 2,5-furandicarboxylic acid (FDCA) has potential applications to replace petroleum-based chemicals. Metal Organic Framework (MOF) can be used as a catalyst to oxidize 5-hydroxymethylfurfural (HMF), producing FDCA. MOF-199 and Ni-BTC were synthesized using solvothermal method with trimesic acid (benzene 1,3,5-tricarboxylic acid/H3BTC) as a linker and Cu or Ni as a metal nod. The physical and chemical properties of catalysts were discovered through characterization using X-ray Diffraction (XRD), Fourier Transform Infra Red (FT-IR), Thermogravimetric Analysis (TGA), Scanning Electron Microscopy - Energy Dispersive X-ray (SEM-EDX), and Ammonia Temperature-programmed Desorption (NH3-TPD). FDCA and its intermediate compounds were produced by converting HMF to FDCA in a small glass batch reactor. The yields of products were then determined by High-Performance Liquid Chromatography (HPLC). HPLC results indicated that there was no DFF (2,5-diformylfuran) signal, indicating that FDCA was formed by FFCA (5-formylfuroic acid) and HMFCA (5-hydroxymethylfuroic acid) formation reaction pathway. The maximum conversion (71%) was obtained using Ni-BTC as a catalyst at 130 °C for 5 h, with FDCA yield of 61.8%. Copyright © 2023 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Abstract Background As a cost-effective and eco-friendly approach, biocatalysis has great potential for the transformation of 5-hydroxymethylfurfural (HMF) into 2,5-furandicarboxylic acid (FDCA). However, the compatibility of each enzyme in the cascade reaction limits the transformation efficiency of HMF to FDCA. Results Coupled with an alcohol oxidase from Colletotrichum gloeosporioides (CglAlcOx), this study aims to study the potential of bacterial laccase from Bacillus pumilus (BpLac) in an enzymatic cascade for 2,5-furandicarboxylic acid (FDCA) biosynthesis from 5-hydroxymethylfurfural (HMF). BpLac showed 100% selectivity for HMF oxidation and generated 5-hydroxymethyl-2-furancarboxylic acid (HMFCA). CglAlcOx was capable of oxidizing HMFCA to 2-formyl-5-furancarboxylic acid (FFCA). Both BpLac and CglAlcOx could oxidize FFCA to FDCA. At the 5 mM scale, a complete transformation of HMF with a 97.5% yield of FDCA was achieved by coupling BpLac with CglAlcOx in the cascade reaction. The FDCA productivity in the reaction was 5.3 mg/L/h. Notably, BpLac could alleviate the inhibitory effect of FFCA on CglAlcOx activity and boost the transformation efficiency of HMF to FDCA. Moreover, the reaction was scaled up to 40 times the volume, and FDCA titer reached 2.6 mM with a yield of 58.77% at 168 h. Conclusions This work provides a candidate and novel insight for better design of an enzymatic cascade in FDCA production.

2,5-Furandicarboxylic acid (FDCA), an eco-friendly biomass resource capable of replacing petroleum-based fuels, is gaining increasing popularity. In this article, 2,5-FDCA was prepared by liquid-phase oxidation of the sustainable precursor 5-hydroxymethylfurfural using the Co–Mn–Br catalyst system. The effects of catalyst concentration, catalyst ratio, reaction temperature, reaction time, reaction pressure, and solvent ratio on the reaction of FDCA were investigated. The products are subjected to qualitative and quantitative analyses using high-performance liquid chromatography, infrared spectroscopy, and hydrogen nuclear magnetic spectroscopy. Moreover, considering the loss of catalytic liquid, the suitable reaction conditions were determined as follows: n(Co)/n(Mn)/n(Br) = 1/0.04/0.5, n(HMF)/n(HAC) = 0.05, reaction temperature of 170°C, reaction pressure of 2 MPa, reaction time 40 min, and airflow rate 1.0 L·min−1. Under these conditions, the yield of the product is 86.01%, the purity is 97.53%, and the loss of the catalytic liquid is about 5.63%, which is at an ideal level and provides a good basis for the recovery of the subsequent catalytic liquid and multiple cycle reactions. Through the optimization of the existing process, the use of noble metal catalysts has been reduced, and the recycling of catalytic liquid has also reduced the consumption of catalysts. This advancement marks a significant stride toward sustainable development in the green chemical industry.

The biomass electrochemical oxidation has attracted worldwide attention owning to its carbon-neutral and sustainable nature. Here, different morphologies of CoCu-carbonate hydroxides (CH) electrodes are prepared through one-step hydrothermal method for 5-hydroxymethylfurfural electrocatalytic oxidation (HMF-ECO) to high-valued 2,5-furandicarboxylic acid (FDCA) for the first time. The results illustrate that Cu can regulate CoCu–CH morphologies from 1D nanorods to 2D ultra-thin nanosheets besides modulating the catalytic compositions. The optimal Co 1 Cu 1 –CH exhibits hybrid nanostructures containing the 1D nanorods and 2D ultra-thin nanosheets, which has the largest ECSA and specific surface area, as well as the smallest Tafel slope and impedance. The oxidation potential of HMF-ECO is 1.42 V vs RHE with the conversion of HMF 99.57%, the selectivity for FDCA 99.91%, and the FE 98.88%. In addition, Cu can promote the conversion of Co2+ to the favorable Co3+ for HMF-ECO on the catalyst surface. Density functional theory calculation indicates that Cu can improve charges transfer to HMF and lower its adsorption energy. In situ Raman spectra tests indicate that cobalt species is the active site for HMF-ECO. Furthermore, at 1.42 V vs RHE, the coupling of HMF-ECO and hydrogen evolution reaction shows that the cathodic hydrogen evolution rate is 92.33 L h−1 m−2, which is 3.69 times more than water splitting. This work provides a special structures material to process intensification of HMF electrooxidation coupling hydrogen production. [Display omitted] • Cu can regulate Co–CH forming different morphologies and nanostructures. • CoCu–CH catalysts exhibit highly efficient for HMF-ECO to FDCA. • HMF-ECO boosts H 2 evolution rate at 92.33 L h−1 m−2, 3.69 times than water splitting. • DFT illustrates Cu can improve charge transfer to HMF and lower its adsorption energy. • In situ Raman shows the cobalt species is the active site. [ABSTRACT FROM AUTHOR]

Platform chemical 2,5-furandicarboxylic acid (FDCA) has potential applications to replace petroleum-based chemicals. Metal Organic Framework (MOF) can be used as a catalyst to oxidize 5-hydroxymethylfurfural (HMF), producing FDCA. MOF-199 and Ni-BTC were synthesized using solvothermal method with trimesic acid (benzene 1,3,5-tricarboxylic acid/H3BTC) as a linker and Cu or Ni as a metal nod. The physical and chemical properties of catalysts were discovered through characterization using X-ray Diffraction (XRD), Fourier Transform Infra Red (FT-IR), Thermogravimetric Analysis (TGA), Scanning Electron Microscopy - Energy Dispersive X-ray (SEM-EDX), and Ammonia Temperature-programmed Desorption (NH3-TPD). FDCA and its intermediate compounds were produced by converting HMF to FDCA in a small glass batch reactor. The yields of products were then determined by High-Performance Liquid Chromatography (HPLC). HPLC results indicated that there was no DFF (2,5-diformylfuran) signal, indicating that FDCA was formed by FFCA (5-formylfuroic acid) and HMFCA (5-hydroxymethylfuroic acid) formation reaction pathway. The maximum conversion (71%) was obtained using Ni-BTC as a catalyst at 130 °C for 5 h, with FDCA yield of 61.8%. [ABSTRACT FROM AUTHOR]

The electrochemical catalytic oxidation of 5-hydroxymethylfurfural (HMF) derived from biomass to produce 2,5-furandicarboxylic acid (FDCA) has attracted significant attention. Herein, the catalyst NiO-N/C composite was prepared and showed high activity for the electrochemical oxidation of HMF. The optimized NiO-N/C composite electrode supported by foamed nickel exhibits 99% conversion of HMF, 84% yield of FDCA, and 96% faradic efficiency. The NiO-N/C composite electrode is stable and remains active after six consecutive measurements. This work provides an effective method for the design and preparation of biomass energy electrocatalysts based on nitrogen-modulated NiO materials. [ABSTRACT FROM AUTHOR]

Spinel copper–manganese oxide catalysts were prepared via the co-precipitation method to be used for the catalytic selective oxidation of 5-hydroxymethylfurfural (HMF) into 2,5-furandicarboxylic acid (FDCA). Morphological characterization revealed that the primary particles of the as-synthesized catalysts were irregular nanoparticles aggregated with each other. The effects of reaction conditions such as time, temperature, and the dosage of oxidant on the catalytic activity were investigated. The experimental results show that the CuMn2O4 showed superior catalytic performance in HMF selective oxidation reaction. In the presence of acetonitrile and tert-butyl hydroperoxide as oxidant, the catalytic reaction can achieve complete conversion of HMF, and the FDCA selectivity reached to 96.4%. The catalyst exhibited good recyclability and recoverability in a three-run recycling test. Mechanism studies reveal that Mn3+ has a significant influence on the catalytic oxidation and the synergistic interaction between Mn and Cu can facilitate the mobility of oxygen thus improving the catalytic activity. [ABSTRACT FROM AUTHOR]

Background: As a cost-effective and eco-friendly approach, biocatalysis has great potential for the transformation of 5-hydroxymethylfurfural (HMF) into 2,5-furandicarboxylic acid (FDCA). However, the compatibility of each enzyme in the cascade reaction limits the transformation efficiency of HMF to FDCA. Results: Coupled with an alcohol oxidase from Colletotrichum gloeosporioides (CglAlcOx), this study aims to study the potential of bacterial laccase from Bacillus pumilus (BpLac) in an enzymatic cascade for 2,5-furandicarboxylic acid (FDCA) biosynthesis from 5-hydroxymethylfurfural (HMF). BpLac showed 100% selectivity for HMF oxidation and generated 5-hydroxymethyl-2-furancarboxylic acid (HMFCA). CglAlcOx was capable of oxidizing HMFCA to 2-formyl-5-furancarboxylic acid (FFCA). Both BpLac and CglAlcOx could oxidize FFCA to FDCA. At the 5 mM scale, a complete transformation of HMF with a 97.5% yield of FDCA was achieved by coupling BpLac with CglAlcOx in the cascade reaction. The FDCA productivity in the reaction was 5.3 mg/L/h. Notably, BpLac could alleviate the inhibitory effect of FFCA on CglAlcOx activity and boost the transformation efficiency of HMF to FDCA. Moreover, the reaction was scaled up to 40 times the volume, and FDCA titer reached 2.6 mM with a yield of 58.77% at 168 h. Conclusions: This work provides a candidate and novel insight for better design of an enzymatic cascade in FDCA production. [ABSTRACT FROM AUTHOR]

Polyethylenefuranoate, a suitable alternative for polyethylene terephthalate, can be synthesized from biomass‐derived 2,5‐furandicarboxylic acid (FDCA), which is obtained via the selective oxidation of 5‐hydroxymethylfurfural (HMF) over noble or non‐noble metal oxide catalysts. However, the FDCA yields using non‐noble metal catalysts can be improved. Hence, in this study, we developed a series of Co‐ and Cu‐embedded melamine sponge (MS)‐derived carbon catalysts (xCo‐Cu/MS) for HMF oxidation, wherein Co and Cu oxides with different Co : Cu ratios were embedded in carbonized MS. The metals were adsorbed on the MS, followed by carbonization. This strategy allowed the uniform distribution of metal clusters in the carbon texture, which enhanced the catalytic activity for HMF conversion and improved the FDCA yield. The good distribution and small crystal size of Co3O4 significantly increased the active surface area, enhancing the catalytic activity. Compared to Co‐Cu/MS catalysts, the 4Co‐Cu/activated carbon catalyst synthesized via impregnation afforded the maximum FDCA yield (93 %) with 100 % HMF conversion at 170 °C and 7 h. Moreover, oxidative regeneration using H2O2 proved to be the best regeneration method for the MS catalysts, with only a 5 % decrease in the FDCA yield after three cycles. [ABSTRACT FROM AUTHOR]

In this work, we prepared a series of bio‐based poly(butylene adipate‐co‐furandicarboxylate) (PBAF) copolyesters with BF segments ranging from 20 to 80 mol% through a two‐step polycondensation. Then, their thermal, mechanical, gas barrier, and degradable properties were investigated. With the increase of BF content, the glass transition temperatures (Tg) and melting temperatures (Tm) of PBAFs increase constantly. Besides, PBAF copolyesters exhibit excellent mechanical performance with elongation at break in the range of 140% to 870%. The elastic modulus and tensile strength of PBAF60 are 138 and 17 MPa respectively, which are comparable to those of commercial poly(butylene adipate‐co‐terephthalate) (PBAT). Moreover, thanks to the structural characteristics of the furan ring, the barrier performances against CO2, O2, and H2O of PBAFs are 4.6–147.5 folds, 4.0–76.0 folds, and 0.8–8.7 folds of PBAT, respectively. Finally, the degradation tests reveal that the weight losses of PBAFs increase with decreasing BF contents. It is worth emphasizing that although the compost degradation rate of PBAF60 is slightly lower than that of PBAT, it is still a prospective alternative to PBAT due to its improved barrier properties. And it provides a possibility for applications in food packaging, mulch films, and structural elements. [ABSTRACT FROM AUTHOR]

The synergistic catalysis of dual metal sites is vital for selective activation of complicated chemical bonds in biomass compounds. The base-free selective oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA) using air as oxidant and water as solvent is a highly sustainable upgrading process for cellulosic carbohydrates. In this work, a series of PtxRu-MgAlO (x = 0.5, 1, 2 and 3, in mole) nanocatalysts with controlled particle sizes (ca. 2 nm) were synthesized by a PVP-assisted adsorption method. The Pt2Ru-MgAlO catalyst showed 99% selectivity of FDCA with full conversion of HMF at only 100 °C under 0.2 MPa of air. In the meantime, an initial reaction rate of HMF of 2.8 mmol molM−1 s−1 and an intrinsic turnover frequency of 61.5 h−1 were attained, respectively. Besides, this catalyst exhibited superior stability during five consecutive reuses without metal leaching. It was disclosed that the Pt-Ru interaction played critical roles in determining the intrinsic activity and the CO bond activation of the prepared PtxRu-MgAlO catalysts. Kinetic experiments combined with in situ chemisorption techniques clearly unraveled adsorption and activation processes of CO bond on Pt0-Ru0 sites. To the best of our knowledge, this work firstly reported a PtRu bimetallic catalyst for aerobic oxidation of HMF and provided insight into synergistic catalysis.

The electrocatalytic conversion of biomass into high-value-added chemicals is one of the effective methods of green chemistry. Conventional metal catalysts have disadvantages, such as low atomic utilization and small surface areas. Catalyst materials derived from metal–organic frameworks (MOFs) have received much attention due to their unique physicochemical properties. Here, an MOF-derived non-precious metal CoxNiyS electrocatalyst was applied to the oxidation of biomass-derivative 5-hydroxymethylfurfural (HMF). The HMF oxidation reaction activities were modulated by regulating the content of Co and Ni bimetals, showing a volcano curve with an increasing proportion of Co. When the Co:Ni ratio was 2:1, the HMF conversion rate reached 84.5%, and the yield of the main product, 2,5-furandicarboxylic acid (FDCA), was 54%. The XPS results showed that the presence of high-valent nickel species after electrolysis, which further proved the existence and reactivity of NiOOH, as well as the synergistic effect of Co and Ni promoted the conversion of HMF. Increasing the content of Ni could increase the activity of HMF electrochemical oxidation, and increasing the content of Co could reduce the increase in the anodic current. This study has important significance for designing better HMF electrochemical catalysts in the future. [ABSTRACT FROM AUTHOR]

Films of poly(ethylene furanoate) (PEF) and poly(neopentyl furanoate) (PNF) of different molecular weights were artificially weathered in a Q‐SUN test chamber for up to 500 h. The chemical and physical changes of the films have been evaluated with a wide range of techniques. All films, independent of molecular weight or crystallinity, show evidence of partial cross‐linking and the formation of new carbonyl species. Furthermore, all irradiated films show changes in thermal properties and crystallization behavior. The extent of degradation was higher for the amorphous films as compared to their semi‐crystalline counterparts, suggesting that UV degradation predominantly occurs in the amorphous phase. The apparent higher UV‐sensitivity of PNF, as compared to PEF, suggests that the nature of the diol, and the resulting polymer properties, affects the UV‐stability of the polymer. Nevertheless, comparison with poly(ethylene terephthalate) (PET) shows that the different electronic structure and properties of the furan ring are the most likely cause of the observed UV‐instability. [ABSTRACT FROM AUTHOR]

The results of a study of Pd/TiO2 and Pd/ZrO2 catalysts prepared by impregnation using different heat treatment conditions in the oxidation reaction of 5-hydroxymethylfurfural (5-HMF) are presented. The catalysts were characterized using XRD analysis, X-ray fluorescence spectroscopy (XFS), low-temperature nitrogen adsorption, and pulse CO adsorption. Catalytic studies were carried out under mild conditions of 5-HMF oxidation at a temperature of 80°C and an oxygen pressure of 5 atm with the use of NaHCO3 as an alkaline agent. It was found that the conditions of thermal treatment significantly affected the formation of an active component in the Pd/TiO2 and Pd/ZrO2 catalysts and determined the dispersity of the active component, its interaction with the support, and, as a consequence, the catalytic properties of the resulting materials. [ABSTRACT FROM AUTHOR]

The present study investigated the preparation of 2,5‐furandicarboxylic acid (FDCA) via the Henkel reaction between furoic acid alkali metal salts and zinc chloride under a continuous CO2 flow at atmospheric pressure. The results obtained were compared with those of previous studies that used high‐pressure conditions or toxic cadmium catalysts. The pathways and rate‐determining steps of the reaction are revealed for the first time. Furthermore, the enhanced formation of FDCA through the promotion of carboxyl exchange and rearrangement during the reaction under a CO2 flow was examined. The CO2‐rich environment afforded a high FDCA yield of 86.30 %, which is the highest yield obtained to date using the Henkel reaction. The findings of this study offer economically improved conditions for large‐scale FDCA production. [ABSTRACT FROM AUTHOR]

2,5-Furandicarboxylic acid (FDCA) is non-toxic, biodegradable, and structurally similar to aromatic di-acids derived from petroleum (petroleum-based aromatic di-acids). In this paper, the polyamide (POF) of FDCA and 4,4′-diaminodiphenyl ether was synthesized in presence of LiCl and N,N-dimethylformamide, and then the new POF membrane was prepared from POF polymer by non-solvent-induced phase separation (NIPS) method. The surface morphology, roughness, contact angle, and zeta potential of the POF membrane surface were well investigated. The results showed that the POF membrane was a hydrophilic, negatively charged, and hard brittle material with high tensile strength. The effects of different POF concentrations in membrane casting solution on the performance of POF membrane were studied through the characterization of flux and interception. When POF concentration was 20 wt%, the prepared membrane exhibited the best performance in long-term stability test, and the flux was 43.9 L m−2 h−1 bar−1, and the rejection rates of the POF membrane for Evans blue, Congo red, and naphthol green B were 95.6%, 93.7%, and 89%, respectively. [ABSTRACT FROM AUTHOR]

Electrooxidation of 5‐hydroxymethylfurfural (HMF) into 2,5‐furandicarboxylic acid (FDCA) is a highly promising approach for producing value‐added chemicals from biomass. However, developing highly efficient electrocatalysts for HMF oxidation (HMFOR) with high current density in large‐scale productions remains a challenge. Herein, it is demonstrated that the Mn‐doped NiS nanosheet electrocatalysts grown directly on 3D graphite felt (GF) substrates can efficiently perform electrooxidation of HMF into FDCA at industrial‐level current density (500 mA cm−2) in the H‐cell. The Mn0.2NiS/GF exhibits excellent HMFOR performance with high selectivity (98.3%), yield (97.6%), faradaic efficiency (94.2%), and robust stability (10 cycles). Especially, FDCA production rate up to 4.56 g h−1 can be achieved, superior to those reported in HMFOR literatures. Furthermore, by scaling up the Mn0.2NiS/GF electrode area and assembling it in a continuous‐flow electrolyzer, high FDCA production rate of 44.32 g h−1 is achieved. The high activity of Mn0.2NiS/GF for HMFOR can be attributed to incorporation of Mn into NiS material, theoretical calculation results indicate that the Mn and Ni as both the adsorption sites for HMF oxidation, thereby effectively facilitate the HMF electro‐oxidation performance. This work provides a strategy for developing potential industrial‐grade electrocatalysts at a large current density. [ABSTRACT FROM AUTHOR]