Highly Efficient Two-Step Synthesis of 2,5-Furandicarboxylic Acid from Fructose without 5-Hydroxymethylfurfural (HMF) Separation: In Situ Oxidation of HMF in Alkaline Aqueous H2O/DMSO Mixed Solvent under Mild Conditions

One-Pot, Solvent Free Synthesis of 2,5-Furandicarboxylic Acid from Deep Eutectic Mixtures of Sugars as Mediated by Bifunctional Catalyst

Currently one-pot conversion of sugars to 2,5-furandicarboxylic acid (FDCA) is of significant interest due to the attainability of sugars as a feedstock and the enormous potential of FDCA as a bioplastic monomer. However, it remains challenging to construct efficient catalysts for this process. In this study, Co3O4 species were anchored to a sulfonated covalent organic framework thus affording a bifunctional catalyst (Co3O4@COF-SO3H). The sulfonic acid sites dehydrate sugars to 5-hydroxymethylfurfural (HMF), which is next oxidized to FDCA as catalyzed by the Co3O4 species. Such a process was applied in the conversion of various binary and ternary deep eutectic mixtures involving choline chloride and sugars without additional solvent. The maximum FDCA yield of 84 % was obtained using glucose-fructose eutectic mixture as the substrates. Moreover, the catalyst was recyclable and stable under the applied reaction conditions. Our process eliminates the employment of organic solvents and expensive noble metal catalysts, resulting in green and economic biomass conversions.

In Situ Electrochemical Conversion of Biomass-Derived 5-Hydroxymethylfurfural into 2,5-Furandicarboxylic Acid by Time-Controlled Aerosol-Assisted Chemical Vapor Deposited FeNi Catalyst

The conversion of 5-hydroxymethylfurfural (HMF) into valuable chemicals, such as 2,5-furandicarboxylic acid (FDCA), is pivotal for sustainable chemical production, offering a renewable pathway to biodegradable plastics and high-value organic compounds. This pioneering study explores the synthesis of FeNi nanostructures via aerosol-assisted chemical vapor deposition (AACVD) for the electrochemical oxidation of HMF to FDCA. By adjusting the deposition time, we developed two distinct nanostructures: FeNi-40, which features nanowires with spherical terminations, and FeNi-80, which features aggregated spherical structures. X-ray diffraction (XRD) confirmed that both nanostructures possess a phase-pure face-centered cubic (FCC) crystal structure. Electrochemical tests conducted using FeNi nanocatalysts on Ni foam revealed that FeNi-40 requires a significantly lower onset potential for HMF oxidation (1.32 V vs RHE) compared to FeNi-80 (1.40 V vs RHE). This difference is attributed to the unique nanowire morphology of FeNi-40, which provides a higher density of active sites and a larger electrochemically active surface area, thereby enhancing the efficiency of the electrochemical process. When tested in an H-type electrolyzer with a Nafion membrane, FeNi-40 demonstrated a remarkable Faradaic efficiency of 96.42% and a high product yield, underscoring the potential of morphology-controlled FeNi nanostructures to enhance the efficiency of sustainable electrochemical processes significantly.

Furandicarboxylate Polyesters: A Comprehensive ADMET Study of a Novel Class of Furan-Based α,ω-Diene Monomers

The present research article delves into the preparation of a new class of bio-based polyesters from α,ω-diene furandicarboxylate monomers. In particular, it exploits the use of acyclic diene metathesis polymerisation (ADMET) on 2,5-furandicarboxylic acid (FDCA)-derived compounds. First, a library of furan-based α,ω-diene monomers was prepared via acid- or base-catalyzed transesterification of 2,5-furandicarboxylic acid dimethyl ester (FDME) with commercially available alcohols incorporating terminal olefins, i. e., allyl alcohol, but-3-en-1-ol, hex-5-en-1-ol and dec-9-en-1-ol. Then, the novel monomers were subjected to ADMET polymerisation employing different catalysts and reaction conditions. Interestingly, first-generation Grubbs catalyst was found to be the best promoter for ADMET polymerisation. This catalyst allowed the preparation of a new family of bio-based polyesters with molecular weights up to 26.4 kDa, with good thermal stability, and adaptable cis-trans conformations. Results also revealed that the monomer structure had a direct impact on the polymerisation efficiency and the resulting thermal properties. The effect of green bio-based solvents such as Cyrene™, dimethyl isosorbide (DMI) and γ-valerolactone (GVL) on the polymerisation process was also studied. Data collected showed that the solvent concentration influenced both the yield and length of polymers formed. Furthermore, some co-polymerisation experiments were conducted; the successful integration of different monomers in the resulting copolymer was shown to affect the glass transition temperature (Tg) of the resulting materials.

Synergistic Interaction between Ruthenium Catalysts and Grafted Niobium on SBA-15 for 2,5-Furandicarboxylic Acid Production Using 5-Hydroxymethylfurfural

This study entailed the synthesis of Ru nanocatalyst decorated on Nb-grafted SBA-15. A Nb-grafted SBA-15 support with varying Nb contents was utilized as a support for the Ru nanoparticles. The effect of Nb grafting on the immobilized Ru nanoparticle catalyst was systematically investigated, and its catalytic performance in the synthesis of furandicarboxylic acid using 5-hydroxymethylfurfural under base-free reaction conditions was evaluated. The results indicate the increased productivity of the Ru@Nb-grafted SBA-15 catalyst with a yield exceeding 95%, representing a significant advancement in catalysis. This study also affords insights into the complex relationship between the catalytic activity and selectivity and its unique surface attributes. Moreover, acidic sites were created, and the electron density within the active sites was modulated by monomeric Nb oxide species on the SBA-15. Additionally, the role of high-electron-density Ru atoms in facilitating the efficient adsorption and activation of the reactant, resulting in enhanced catalytic efficacy, was highlighted.

A Facile Synthesis Route to AuPd Alloys for the Selective Oxidation of 5-Hydroxymethylfurfural to 2,5-Furandicarboxylic Acid

Synthesis of 2,5-furandicarboxylic acid (FDCA) can be achieved via catalytic oxidation of 5-hydroxymethylfurfural (5-HMF), in which both base and catalyst play important roles. This work presents the development of a simple synthesis method (based on a commercial parent 10 wt.% Pd/C catalyst) to prepare the bimetallic AuPd alloy catalysts (i. e., AuPd/C) for selective 5-HMF oxidation to FDCA. When using the strong base of NaOH, Pd and Au cooperate to promote FDCA formation when deployed either separately (as a physical mixture of the monometallic Au/C and Pd/C catalysts) or ideally alloyed (AuPd/C), with complete 5-HMF conversion and FDCA yields of 66 % vs 77 %, respectively. However, NaOH also promoted the formation of undesired by-products, leading to poor mass balances (<81 %). Comparatively, under weak base conditions (using NaHCO3 ), an increase in Au loading in the AuPd/C catalysts enhances 5-HMF conversion and FDCA productivity (due to the enhanced carbonyl oxidation capacity) which coincides with a superior mass balances of >97 %. Yet, the excessive Pd content in the AuPd/C catalysts was not beneficial in promoting FDCA formation.

Marine plant-based biorefinery for sustainable 2,5-furandicarboxylic acid production: A review

Marine plants, including macroalgae and seagrass, show promise as biorenewable feedstocks for sustainable chemical manufacturing. This study explores their potential in producing 2,5-furandicarboxylic acid (FDCA), a versatile platform chemical for commodity polymers. FDCA-based polyethylene 2,5-furandicarboxylate offers a sustainable alternative to petroleum-derived polyethylene terephthalate, commonly used in plastic bottles. Our research pioneers the concept of a marine plant-based FDCA biorefinery, introducing innovative approaches for sustainability and cost-effectiveness. This review outlines the use of ionic liquid-based solvents (ILS) and deep eutectic solvent (DES) systems in FDCA production. Additionally, we propose biomodification strategies involving target enzyme-encoding genes to enhance the depolymerization of non-structural storage glucans in marine plants. Our findings pave the way for eco-friendly biorefineries and biorenewable plastics.

Catalytic conversion of cellulosic biomass to harvest high-valued organic acids

Catalytic conversion of biomass provides an alternative way for the production of organic acids from renewable feedstocks. The emerging process contains complex reactions and strategies to cut down those complex biogenic materials into target molecules. Here, we review the catalytic conversion of cellulosic biomass toward high-valued organic acids. This work has summarized the key controlling reactions which lead toward formic acid, glycolic acid, or sugar acids in oxidative conditions and the main pathways for lactic acid or levulinic acid in the anaerobic environment from cellulosic biomass and its derivatives. We evaluate and compare different strategies and methods such as one-pot and two-step conversion. Additionally, the optimization of catalytic reactions has been discussed to realize the design of C-C coupling reactions, the development of multifunctional materials, and new efficient system. In all, this article gives an insight guide to precisely convert cellulosic biomass into target organic acids.

Segmental mobility in sustainable copolymers based on poly(lactic acid) blocks built onto poly(butylene succinate) in situ

Two series of newly synthesized sustainable block copolymers based on poly(butylene succinate) (PBSu) and polylactide (PLA) were studied. The copolymers were synthesized by a ring-opening polymerization of PLA in the presence of two initial PBSu of low molar mass. We focused on the effects of the PBSu/PLA ratio (1/99 up to 15/85), chain length and initial PBSu length on the final thermal transitions in the copolymers with an emphasis on molecular mobility/dynamics and subsequently on crystallization. Both aspects are considered relevant to the final materials performance, as well as facilitation of polymer renewability. Calorimetry and dielectric spectroscopy were the main investigation tools. In the amorphous state (i.e., in which the direct effects of copolymer structure are assessable), the segmental mobility of neat PLA was significantly faster in the copolymers. Segmental mobility was monitored via the decrease in the calorimetric and dielectric (α relaxation) glass-transition temperatures, Tg and Tg,diel, respectively. The effect was systematic with an increase in the PBSu/PLA ratio, and was rationalized through the plasticizing role of PBSu (low-Tg component) and facilitated also by the simultaneous lowering of the chain length in the copolymers. Dielectric spectroscopy allowed evaluation of the dynamical fragility (cooperativity) of chains, which was strongly suppressed in the copolymers. This finding suggested an increase in free volume or a gradual increase of interchain distances. This phenomenon could favor the natural enzymatic degradation of the systems (compostability), which is limited in neat PLA. We recorded enhancement of nucleation and the crystalline fraction in the copolymers that was likely connected with faster chain diffusion. Further lowering of the Tg with the implementation of crystallization was noted (which seemed a controversial effect) but which indicated crystallization-induced phase separation.

Catalytic Hydroconversion of 5-HMF to Value-Added Chemicals: Insights into the Role of Catalyst Properties and Feedstock Purity

5-hydroxymethylfurfural (HMF) is an important bio-derived platform molecule that is generally obtained from hexoses via acid-catalyzed dehydration. It can be effectively transformed into a variety of value-added derivatives, thus being an ideal candidate for fossil replacement. Both HMF oxidation and hydrogenation processes enable the synthesis of numerous chemicals, monomers for polymerization, and biofuel precursors. This Review summarizes the most recent advances in heterogeneous catalytic hydroconversion of HMF into valuable chemicals with strong focus on 2,5-bishydroxymethyl furan (BHMF), 2,5-bishydroxymethyltetrahydrofuran (BHMTHF), and 2,5-dimethyltetrahydrofuran (DMTHF). In addition, multifunctional catalytic systems that enable a tunable production of various HMF derived intermediates are discussed. Within this chemistry, the surprising impact of HMF purity on the catalytic performance, such as selectivity and activity, during its upgrading is highlighted. Lastly, the remaining challenges in the field of HMF hydroconversion to the mentioned chemicals are summarized and discussed, taking into account the knowledge gain of catalyst properties and feedstock purity.

One-Pot Synthesis of 2,5-Furandicarboxylic Acid from 2-Furoic Acid by a Pd-catalyzed Bromination-Hydroxycarbonylation Tandem Reaction in Acetate Buffer

The one-pot synthesis of 2,5-furandicarboxylic acid from 2-furoic acid with a yield of 57 % was achieved for the first time using a Pd-catalyzed bromination-hydroxycarbonylation tandem reaction in HOAc-NaOAc buffer. This synthetic protocol shows major improvements compared to previously reported methods, such as using biomass-based 2-furoic acid as low-cost raw material, one-pot synthesis without isolation of intermediate products, and no need for an acidification procedure. Experiments indicate that the involved Xantphos-modified Pd-catalyst and the buffer solution play significant promoting roles for each individual reaction whereas Br2 (as the brominating reagent) had a negative effect on the second hydroxycarbonylation step, while CO was deleterious for the first bromination step. Hence, in this practical one-pot synthesis, Br2 should be consumed in the first bromination step as fully as possible, and CO is introduced after the first bromination step has been completed.

Conversion of inulin-rich raw plant biomass to 2,5-furandicarboxylic acid (FDCA): Progress and challenge towards biorenewable plastics

The current commercial plastic manufactures have been produced using petroleum-based resource. However, due to concerns over the resource depletion and the environmental sustainability, bioresource-based manufacturing processes have been developed to cope against these concerns. Bioresource-derived 2,5-furandicarboxylic acid (FDCA) can be utilized as a building block material for plastic manufactures. To date, numerous technologies have been developed for the production of FDCA using various types of bio-based feedstocks such as hydroxymethylfurfural (HMF), 6-C sugars, and polysaccharides. The commercial companies produce FDCA using HMF-based production processes due to their high production efficiency, but the high price of HMF is a problem bottleneck. Our review affords important information on breakthrough approaches for the cost-efficient and sustainable production of FDCA using raw plant feedstocks rich in inulin. These approaches include bioprocessing technology based on the direct use of raw plant feedstocks and biomodification of the target plant sources. For the former, an ionic liquid-based processing system is proposed for efficient pretreatment of raw plant feedstocks. For the latter, the genes encoding the key enzymes; sucrose:sucrose 1-fructoyltransferase (1-SST), fructan:fructan 1-fryuctosyltransferase (1-FFT), fructan 1-exohydrolase (1-FEH), and microbe-derived endoinulinase, are introduced for biomodification conducive to facilitating bioprocess and improving inulin content. These approaches would contribute to cost-efficiently and sustainably producing bio-based FDCA.

2,5-Furandicarboxylic acid production from furfural by sequential biocatalytic reactions

2,5-Furandicarboxylic acid (FDCA) is a valuable compound that can be synthesized from biomass-derived hydroxymethylfurfural (HMF), and holds great potential as a promising replacement for petroleum-based terephthalic acid in the production of polyamides, polyesters, and polyurethanes used universally. However, an economical large-scale production strategy for HMF from lignocellulosic biomass is yet to be established. This study aimed to design a synthetic pathway that can yield FDCA from furfural, whose industrial production from lignocellulosic biomass has already been established. This artificial pathway consists of an oxidase and a prenylated flavin mononucleotide (prFMN)-dependent reversible decarboxylase, catalyzing furfural oxidation and carboxylation of 2-furoic acid, respectively. The prFMN-dependent reversible decarboxylase was identified in an isolated strain, Paraburkholderia fungorum KK1, whereas an HMF oxidase from Methylovorus sp. MP688 exhibited furfural oxidation activity and was used as a furfural oxidase. Using Escherichia coli cells coexpressing these proteins, as well as a flavin prenyltransferase, FDCA could be produced from furfural via 2-furoic acid in one pot.

Heterogeneous Catalytic Conversion of Sugars Into 2,5-Furandicarboxylic Acid

Achieving the goal of living in a sustainable and greener society, will need the chemical industry to move away from petroleum-based refineries to bio-refineries. This aim can be achieved by using biomass as the feedstock to produce platform chemicals. A platform chemical, 2,5-furandicarboxylic acid (FDCA) has gained much attention in recent years because of its chemical attributes as it can be used to produce green polymers such polyethylene 2,5-furandicarboxylate (PEF) that is an alternative to polyethylene terephthalate (PET) produced from fossil fuel. Typically, 5-(hydroxymethyl)furfural (HMF), an intermediate product of the acid dehydration of sugars, can be used as a precursor for the production of FDCA, and this transformation reaction has been extensively studied using both homogeneous and heterogeneous catalysts in different reaction media such as basic, neutral, and acidic media. In addition to the use of catalysts, conversion of HMF to FDCA occurs in the presence of oxidants such as air, O2, H2O2, and t-BuOOH. Among them, O2 has been the preferred oxidant due to its low cost and availability. However, due to the low stability of HMF and high processing cost to convert HMF to FDCA, researchers are studying the direct conversion of carbohydrates and biomass using both a single- and multi-phase approach for FDCA production. As there are issues arising from FDCA purification, much attention is now being paid to produce FDCA derivatives such as 2, 5-furandicarboxylic acid dimethyl ester (FDCDM) to circumvent these problems. Despite these technical barriers, what is pivotal to achieve in a cost-effective manner high yields of FDCA and derivatives, is the design of highly efficient, stable, and selective multi-functional catalysts. In this review, we summarize in detail the advances in the reaction chemistry, catalysts, and operating conditions for FDCA production from sugars and carbohydrates.

Biocatalytic production of 2,5-furandicarboxylic acid: recent advances and future perspectives

2,5-Furandicarboxylic acid (FDCA) is attracting increasing attention because of its potential applications as a sustainable substitute to petroleum-derived terephthalic acid for the production of bio-based polymers, such as poly(ethylene 2,5-furandicarboxylate) (PEF). Many catalytic methods have been developed for the synthesis of FDCA, including chemocatalysis, biocatalysis, photocatalysis, and electrocatalysis. Biocatalysis is a promising approach with advantages that include mild reaction condition, lower cost, higher selectivity, and environment amity. However, the biocatalytic production of FDCA has hardly been reviewed. To fully understand the current research developments, this review comprehensively considers the research progress on toxic effects and biodegradation of furan aldehydes, and then summarizes the latest achievements concerning the synthesis of FDCA from 5-hydroxymethylfurfural and other chemicals, such as 2-furoic acid and 5-methoxymethylfurfural. Our primary focus is on biocatalytic methods, including enzymatic catalysis (in vitro) and whole-cell catalysis (in vivo). Furthermore, future research directions and general developmental trends for more efficient biocatalytic production of FDCA are also proposed.

Direct Catalytic Route to Biomass-Derived 2,5-Furandicarboxylic Acid and Its Use as Monomer in a Multicomponent Polymerization

Efficient synthesis of valuable platform chemicals from renewable feedstock is a challenging, yet essential strategy for developing technologies that are both economical and sustainable. In the present study, we investigated the synthesis of 2,5-furandicarboxylic acid (FDCA) in a two-step catalytic process starting from sucrose as largely available biomass feedstock. In the first step, 5-(hydroxymethyl)furfural (HMF) was synthesized by hydrolysis and dehydration of sucrose using sulfuric acid in a continuous reactor in 34% yield. In a second step, the resulting reaction solution was directly oxidized to FDCA without further purification over a Au/ZrO₂ catalyst with 84% yield (87% selectivity, batch process), corresponding to 29% overall yield with respect to sucrose. This two-step process could afford the production of pure FDCA after the respective extraction/crystallization despite the impure intermediate HMF solution. To demonstrate the direct application of the biomass-derived FDCA as monomer, the isolated product was used for Ugi-multicomponent polymerizations, establishing a new application possibility for FDCA. In the future, this efficient two-step process strategy toward FDCA should be extended to further renewable feedstock.