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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 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]

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]

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]

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]

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]

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]

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]

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 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]

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]

Bio‐based 2,5‐furandicarboxylic acid (FDCA) can be used to produce poly(ethylene 2,5‐furandicarboxylate) (PEF), which has a great potential for barrier packaging, and so forth. Herein, the first two steps of the esterification reaction of FDCA with ethylene glycol (EG) were investigated. The dissolution rate of FDCA in EG is fast, the solubility of FDCA in EG and monohydroxyethyl 2,5‐furandicarboxylate (MHEF) reaches 159.12 and 489.84 g kg−1 at 180 °C, respectively. The initial esterification of FDCA with EG to form MHEF is a zero‐order reaction (k1 = 266.77 × 10−3 mol kg−1 min−1) with an activation energy of 114.52 kJ mol−1; the esterification of MHEF with EG to form bis(hydroxyethyl) 2,5‐furandicarboxylate (BHEF) is a first‐order reaction (k2 = 9.72 × 10−3 min−1) with an activation energy of 86.12 kJ mol−1. These results identified accurate parameters for the dissolution and esterification processes of FDCA in EG, which provide important guidance for the polymerization of FDCA polyesters. [ABSTRACT FROM AUTHOR]

The electrochemical transformation of biomass to high value‐added products is attractive. Herein, Cu sulfide‐mediated in‐situ synthesis of Cu oxide was achieved for efficient electro‐oxidation of biomass derived 5‐hydroxymethylfurfural (HMF) to 2,5‐furandicarboxylic acid (FDCA). The copper foam‐supported Cu sulfide (Cu−S/CF) was in‐situ converted to Cu oxide during the electro‐oxidation process. The in‐situ formed Cu oxide presented high HMF conversion, FDCA yield, and faradaic efficiency in 1 m KOH with HMF concentration up to 100 mm. The oxidation of HMF on Cu oxide started with the formation of high‐valence Cu species with the assistance of OH−, which then oxidized HMF spontaneously. An anion exchange membrane (AEM) electrolyzer with Cu−S/CF as the anode was assembled to continuously produce FDCA with H2 generation at the cathode. The AEM electrolyzer ran stably for 60 h with FDCA content higher than 85 % at a cell voltage between 1.50 and 1.60 V. [ABSTRACT FROM AUTHOR]

A resource‐efficient and facile method of synthesizing 2,5‐furandicarboxylic acid (FDCA) from biomass‐derived platform chemical 5‐hydroxymethylfurfural (HMF) was explored using cobalt and nitrogen‐doped carbon catalysts (Co/N−C). A molten salts‐assisted method proved to be effective in improving the surface area of the catalysts as well as uniformity and dispersibility of the Co species. Detailed investigation of different combinations of precursors revealed that the formation of Co−Nx species was imperative for high FDCA selectivity, and the nitrogen‐doped carbon matrix enhanced the catalytic activity by providing good electron mobility. A significant observation was made regarding the change in reaction mechanism with the heating rate of Co/N−C. High HMF conversion of 99 % with 68 % FDCA yield was achieved at 120 °C in water at 24 h. This study shows an eco‐friendly and cost‐effective method of FDCA production with high yield that overcomes the use of precious metal‐based catalysts, organic solvents, and severe reaction conditions. [ABSTRACT FROM AUTHOR]

The selective photo‐oxidation of biomass‐derived 5‐hydroxymethylfurfural (HMF) to 2,5‐furandicarboxylic acid (FDCA) is important due to its substitute‐role in polyester‐fabrication. Here, a titanium‐cluster based metal‐covalent organic framework nanosheet has been synthesized through the covalent‐coupling between Ti6‐NH2 and benzotrithiophene tricarbaldehyde (BTT). The integration of them endows the nanosheet with a visible‐light‐adsorption region, effective electron‐hole separation‐efficiency and suitable photo‐oxidation ability. Specifically, its photo‐selectivity for HMF‐to‐FDCA can be >95 % with ≈100 % conversion, which is more than 2, 5, and 10 times higher than MOF‐901 (43 %), Ti6‐NH2 (19 %) and under‐darkness (9 %), respectively. Notably, an O2‐based mechanism is proposed and the vital roles of Ti6‐NH2 and BTT are verified by DFT calculations. This work might facilitate the exploration of porous‐crystalline‐catalysts for selective biomass‐valorization. [ABSTRACT FROM AUTHOR]

The present study focused on developing a stable basic MnOx support for Ru (RuMn) for the efficient oxidation of 5‐hydroxymethylfurfural (HMF) to 2,5‐furandicarboxylic acid (FDCA) in water in the absence of an external base. A series of MnOx supports, synthesized via hydrothermal approach using urea as precipitant, was prepared by thermal treatment at various temperatures (300–800 °C) before doping with Ru. The RuMn‐2 (1 wt % Ru, MnOx calcined at 400 °C) possessed a large number of basic sites (1.72 mmol g−1) based on CO2 temperature‐programmed desorption analysis, affording an FDCA yield of 87 % with a turnover frequency of 22 h−1. Transmission electron microscopy energy‐dispersive X‐ray spectroscopy elemental mapping of RuMn‐2 showed a high dispersion of Ru over the surface of MnOx, contributing to the efficient HMF oxidation. Moreover, X‐ray diffraction, X‐ray photoelectron spectroscopy, and H2 temperature‐programmed reduction indicated that the predominant MnO2 phase (ϵ‐MnO2) played a vital role in HMF oxidation. RuMn‐2 was recyclable for up to four runs without significant loss in the activity and retained its structural integrity. [ABSTRACT FROM AUTHOR]

We report the phosphorylation‐assisted polymerization and characterization of 2,5‐furandicarboxylic acid (FDCA)‐based wholly aromatic polyamide. For this purpose, poly(3,4′‐oxydiphenylene furanamide) (PODFA) was synthesized via solution polymerization of FDCA with 3,4′‐oxydiphenylamine (ODPA) in the presence of triphenyl phosphite and pyridine. The spectroscopic analyses and solution viscosity measurement revealed the successful synthesis of a relatively high molecular weight PODFA with good solubility in a variety of polar aprotic solvents without inorganic salts. PODFA could be thus processed into purely amorphous films with high flexibility in bending and folding deformation. The 39 μm thick PODFA film exhibited optical transparency, and the 65–100 μm thick films showed a transparent yellow or light brown color. The amorphous PODFA films were characterized to have excellent thermal and static mechanical properties in terms of a glass transition temperature of ~260°C, a thermal decomposition peak temperature of ~450°C, a residue of ~50% at 800°C under nitrogen gas condition, an initial modulus of 12.98 ± 1.84 GPa, a tensile strength of 84.6 ± 17.3 MPa, and a strain at break of 2.3 ± 1.5% at room temperature. [ABSTRACT FROM AUTHOR]

2,5‐Furandicarboxylic acid (FDCA) is a green and renewable substitute to terephthalic acid (TPA), the fundamental monomer of polyethylene terephthalate (PET) plastic. This work investigated novel supported Keggin phosphormolybdic acids (HPMs) for the synthesis of FDCA from 5‐hydroxymethylfurfural (HMF) in imidazole ionic liquids. Among four supporters, Al2O3, SiO2, ZSM‐5 and SBA‐15, SBA‐15 exhibited highest stability and specific surface area 507 m2/g. FDCA yield achieved 76 % by using HPM/SBA‐15, and maintained 60 % after 5 runs. Particularly, [Bmim]Cl ionic liquid was stable both in thermal and chemical properties by confirmation of FTIR and NMR. HPM/SBA‐15 was also employed in different monosaccharides to FDCA, and led to acceptable yields. A moderate FDCA yield of 34 % from glucose was obtained, revealing a great potential of one‐pot synthesis of FDCA from renewable and accessible carbohydrates. [ABSTRACT FROM AUTHOR]

2,5‐Furandicarboxylic acid (FDCA) is one of the promising renewable plastic monomers enabling to address several environmental issues, instead of petroleum‐based terephthalic acid (TPA). In this study, an integrative process for the co‐production of FDCA and furfural as well as activated carbon was developed, and the economic feasibility and environmental sustainability for the proposed process were evaluated. In the proposed process, there were major four catalytic conversion reactions: (1) hydrolysis of biomass to its derivatives (cellulose, hemicellulose, and lignin), (2) dehydration of hemicellulose to furfural, (3) dehydration of cellulose to 5‐hydroxymethylfurfural (HMF), and (4) successive oxidation of HMF to FDCA. Particularly, a heat exchanger network coupled with a heat pump was established to minimize the utility consumption, thereby reducing 72 % of the heating requirement. Techno‐economic analysis revealed that the minimum selling price of FDCA was $1380 ton−1, which is comparable to that of petroleum‐based TPA ($1445 ton−1). Uncertainty analysis using the Monte Carlo simulation method was employed to quantify the risk associated with the unforeseen market condition. From the life‐cycle assessment, we observed that the proposed process is more environmentally sustainable than conventional TPA production in terms of climate change and fossil depletion metrics. [ABSTRACT FROM AUTHOR]

A great deal of attention has been directed toward studying the electrochemical oxidation of 5‐hydroxymethylfurfural (HMF), a molecule that can be obtained from biomass‐derived cellulose and hemicellulose, to 2,5‐furandicarboxylic acid (FDCA), a molecule that can replace the petroleum‐derived terephthalic acid in the production of widely used polymers such as polyethylene terephthalate. NiOOH is one of the best and most well studied electrocatalysts for achieving this transformation; however, the mechanism by which it does so is still poorly understood. This study quantitatively examines how two different dehydrogenation mechanisms on NiOOH impact the oxidation of HMF and its oxidation intermediates on the way to FDCA. The first mechanism is a well‐established indirect oxidation mechanism featuring chemical hydrogen atom transfer to Ni3+ sites while the second mechanism is a newly discovered potential‐dependent (PD) oxidation mechanism involving electrochemically induced hydride transfer to Ni4+ sites. The composition of NiOOH was also tuned to shift the potential of the Ni(OH)2/NiOOH redox couple and to investigate how this affects the rates of indirect and PD oxidation as well as intermediate accumulation during a constant potential electrolysis. The new insights gained by this study will allow for the rational design of more efficient electrochemical dehydrogenation catalysts. [ABSTRACT FROM AUTHOR]

2,5‐Furandicarboxylic acid (FDCA) is currently considered one of the most relevant bio‐sourced building blocks, representing a fully sustainable competitor for terephthalic acid as well as the main component in green polymers such as poly(ethylene 2,5‐furandicarboxylate) (PEF). The oxidation of biobased 5‐hydroxymethylfurfural (HMF) represents the most straightforward approach to obtain FDCA, thus attracting the attention of both academia and industries, as testified by Avantium with the creation of a new plant expected to produce 5000 tons per year. Several approaches allow the oxidation of HMF to FDCA. Metal‐mediated homogeneous and heterogeneous catalysis, metal‐free catalysis, electrochemical approaches, light‐mediated procedures, as well as biocatalytic processes share the target to achieve FDCA in high yield and mild conditions. This Review aims to give an up‐to‐date overview of the current developments in the main synthetic pathways to obtain FDCA from HMF, with a specific focus on process sustainability. [ABSTRACT FROM AUTHOR]

Conversion of biomass into biofuels and high value‐added chemicals is a promising strategy to solve the increasingly deteriorating environmental problems caused by fossil energy consumption. The development of efficient technologies and methods is the premise and guarantee to realize the high‐value conversion of biomass. 5‐Hydroxymethylfurfural (HMF), as a versatile biomass platform compound, is generated via dehydration of hexoses (e. g., fructose and glucose) derived from cellulosic biomass. This Review gives an overview of the advances and challenges of electro‐ and photocatalytic oxidation of biomass‐derived HMF to high‐value chemicals such as 2,5‐formylfuran (DFF) and 2,5‐furandicarboxylic acid (FDCA). These strategies and methods for the preparation of high‐value chemicals by electro‐ and photocatalytic oxidation of HMF, coupled with, for example, hydrogen evolution reaction, organic substrate reduction, CO2 reduction reaction, or N2 reduction reaction, were summarized and discussed. Moreover, the catalytic efficiency and mechanism of different types of catalysts were also introduced in these conversion systems. [ABSTRACT FROM AUTHOR]

The oxidation of 5‐hydroxymethylfurfural (HMF) produces value‐added chemicals such as 2,5‐diformylfuran (DFF) and 2,5‐furandicarboxylic acid (FDCA). In this work, FDCA production was achieved by oxidation of crude HMF solution containing around 45 % HMF and unwanted byproducts such as 5,5′‐[oxy‐bis(methylene)]bis‐2‐furfural (HMF dimer) and polymers. At optimized reaction conditions similar to the Mid‐Century process, homogeneous oxidation of the crude HMF (up to 20 wt% in the feed) by Co/Mn/Br catalyst in acetic acid solution produced FDCA at >95 % yield. The solid FDCA product contained <4000 ppm 5‐formyl‐2‐furancarboxylic acid (FFCA). Such high yields were observed because the impurities in crude HMF were also converted to FDCA, as confirmed by the facile oxidation of HMF dimer to FDCA under reaction conditions. The successful demonstration of crude HMF as feed, obviating the need for HMF purification, suggests potential for cost‐effectively producing FDCA in existing terephthalic plants. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

The supported bimetallic AuPd nanoparticles hold great promise for the selective oxidation of 5‐hydroxymethylfurfural (HMF) to 2, 5‐furan dicarboxylic acid (FDCA), a substitute for petroleum derivative terephthalic acid (TPA). Herein, by combining a versatile Pickering high internal phase emulsions (HIPEs) template with subsequent carbonization process, cobalt‐based hierarchical porous carbon (CoOx−HPC) support was obtained. After loading bimetallic AuPd nanoparticles through the sol‐gel method, AuPd/CoOx−HPC catalyst was successfully synthesized. By changing the Pickering HIPEs parameters, carbonization temperature, the porous structure and cobalt valence of as‐synthesized catalyst can be adjusted. The obtained catalysts were systematically characterized by SEM, TEM, N2 adsorption‐desorption, XRD, XPS, and TGA. Benefiting from the synergistic effects of the high porosity of CoOx−HPC support and efficient AuPd nanoparticles, tandem oxidation of HMF to FDCA can be carried out in the water. We have clarified that the catalysts with various cobalt valence states showed superior performance, and the highest FDCA yield of 97.2 % will be obtained under the optimal reaction conditions. Meanwhile, the kinetics study indicated that the oxidation of FFCA to FDCA was the rate‐determining step. Moreover, the AuPd/CoOx−HPC catalyst revealed excellent stability in HMF oxidation during four cycles. The experimental results demonstrated that as‐prepared AuPd/CoOx−HPC catalysts are efficient towards FDCA production from the selective oxidation of HMF. [ABSTRACT FROM AUTHOR]

The current trend of developing novel biobased polymeric materials is focused more on utilizing the unique structural/physical properties of renewable building blocks towards niche market applications. In this work, with the aim of developing low‐crystallinity to amorphous polyesters with enhanced thermal properties, a series of copolyesters based on rigid and structurally asymmetric carbohydrate‐derived building blocks, namely furan‐2,5‐dicarboxylic acid and isosorbide, and 1,4‐butanediol were successfully synthesized using melt polycondensation. The copolyesters were obtained with varied chemical compositions and rather high molecular weights (Mn = 24 000–31 000 g mol−1) and intrinsic viscosities ([η] = 0.56–0.72 dL g−1). Incorporation of both building blocks significantly enhances the glass transition temperatures (Tg = 38–107 °C) of polyesters, and also efficiently inhibits the crystallization of the copolyesters. A low content of isosorbide (ca 10 mol%) leads to complete transition of the homopolyester to nearly fully amorphous materials. Detailed characterizations of the chemical structures and thermal properties of the synthesized copolyesters were conducted using various analytical techniques. In addition, hydrolytic and enzymatic degradations of the copolymers in the presence of porcine pancreatic lipase and cutinase were also investigated. © 2020 Society of Industrial Chemistry [ABSTRACT FROM AUTHOR]

5‐Hydroxymethylfurfural (HMF) has been identified as one of the most promising biomass‐based multi‐purpose platform molecules. Innovative protocols, namely electrocatalysis, photocatalysis, and microwave (MW)‐assisted chemistry, as well as continuous‐flow systems, add a new dimension and another promising toolbox for the oxidation of HMF in recent years. This Minireview deals with recent progress in the catalytic oxidation of HMF to 2,5‐furandicarboxylic acid (FDCA) and other intermediates using noble, non‐noble, and metal‐free systems deploying emerging protocols. Selective HMF downstream oxidation products could be obtained not only via common catalyst modifications, namely nature of the metal, preparative method, and the property of deployed support, but also by using innovative processes. [ABSTRACT FROM AUTHOR]

The electrochemical conversion of 5‐hydroxymethylfurfural (HMF) to 2,5‐furandicarboxylic acid (FDCA) is an attractive strategy for producing sustainable substitutes for petroleum‐derived polymers. Developing acidic electrocatalysis system is of great significance for the separation of FDCA and improves the efficiency of the whole electrolyzer, which is limited by the availability of effective catalysts. Here, we report a TiOx@MnOx electrocatalyst, which can obtain FDCA precipitation in one‐step in acidic media. The TiOx@MnOx catalyst with the active MnOx species confined in the acid‐resistant TiOx nanowires, and obtained a consistent yield of FDCA precipitation in the continuous conversion of 100 mM HMF (∼24 % under the stoichiometric charge). Electrochemical impedance analyses and electrolysis experiments revealed that the catalytic performance of TiOx@MnOx is related to the concentration of HMF. Further research found that the electrolyzer, electrolysis potential, reaction temperature, and HMF concentration affect the yield and FE of FDCA. This work demonstrates TiOx@MnOx is a practical and inexpensive catalyst for the sustainable synthesis of FDCA in an acidic electrocatalysis system. [ABSTRACT FROM AUTHOR]

In the present study, amino‐functionalised mesoporous silica microspheres were utilised as support for the covalent immobilisation of Candida antarctica lipase B (CaLB) for the subsequent production of 2,5‐furandicarboxylic acid (FDCA) from 2,5‐diformylfuran (DFF). Under the optimised operating conditions of pH 6.5, particle/enzyme ratio of 1.25:1.0 and glutaraldehyde concentration of 4 mM, a maximum CaLB immobilisation yield of 82.4% on silica microspheres was obtained in 12.25 h. The immobilised CaLB was used for the synthesis of alkyl esters, which were utilised along with hydrogen peroxide for FDCA synthesis. The biocatalytic conversion of 30 mM DFF dictated a 77–79% FDCA in 48 h at 30°C; where the turnover number and turnover frequency of immobilised CaLB were 6220.73 mol mol−1 and 129.59 h−1, respectively, for ethyl acetate, against 6297.65 mol mol−1 and 131.2 h−1, respectively, for ethyl butyrate. Upon examining the operational stability, the immobilised CaLB exhibited high stability till five cycles of FDCA production. [ABSTRACT FROM AUTHOR]

Selective aerobic oxidation of biomass‐derived 5‐hydroxymethylfurfural (HMF) into high value‐added 2,5‐furandicarboxylic acid (FDCA) is regarded as one of the most attractive biomass transformations due to a wide range of its application prospects, particularly as an important renewable alternative to petroleum‐derived terephthalic acid in the synthesis of useful polymers. Herein, a novel MnOx−CeO2 (MC) supported palladium catalyst was synthesized and applied for the aerobic oxidation of HMF into FDCA in KHCO3 aqueous solution. The physical and chemical properties of the obtained catalysts were systematically characterized by TEM, N2 adsorption and desorption, XRD, TG, XPS, and H2‐TPR characterization methods. And the highest yield of FDCA at 92.5 % was achieved under the optimal reaction conditions. Moreover, regeneration tests revealed the synthesized Pd/MC catalyst can be recovered and reused at least five times without significant loss of catalytic activity. The developed facile reaction system with Pd/MC catalysts offers a new route to large‐scale and economically viable processes for the oxidation of HMF into FDCA. [ABSTRACT FROM AUTHOR]

A series of gold nanoparticles in the 4–40 nm range were prepared, immobilized on activated carbon and further tested, at low base concentration, in the catalytic oxidation of 5‐hydroxymethyl furfural (HMF) to 2,5‐furandicarboxylic acid (FDCA). Gold particles size variation has no influence on HMF conversion but significantly affects product selectivity and carbon balance. This behavior is ascribed to the thermodynamically favorable oxygen reduction reaction on Au(100) faces. As the gold particle size decreases the Au(100)/Au(111) exposure ratio, estimated by using the van Hardeveld‐Hartog model, increases as well as the FDCA selectivity. The smaller the gold particle size the smaller the 5‐hydroxymethyl‐2‐furancarboxylic acid (HMFCA) to FDCA ratio pointing to the gold size dependent behavior of the oxidation of the alcohol function of the HMF molecule. [ABSTRACT FROM AUTHOR]

2,5‐furandicarboxylic acid (2,5‐FDCA) produced from 5‐hydroxymethylfurfural (5‐HMF) is a promising renewable alternative to terephthalic acid. In this work, we prepared a Cu−Ni bimetallic catalyst with a CuNi(OH)2 structure by incipient wetness impregnation. This catalyst gave a 9.2 mA cm−2 current density for 5‐HMF oxidation at 1.45 V vs RHE. Finally, 100 % conversion of HMF with 93.3 % yield of 2,5‐FDCA was obtained. [ABSTRACT FROM AUTHOR]

The oxidation reaction of 5‐hydroxymethylfurfural to the bioplastic monomer 2,5‐furandicarboxylic acid over heterogenous resin‐supported Pt catalysts was investigated in detail, under continuous flow, base‐free conditions, and in neat water. The product was continuously obtained in 99 % yield by running the reaction at 120 °C, 303 s residence time, 1.2 mL min−1 O2 flow rate, and 7.7 bar O2 pressure. The product was isolated with a high space‐time‐yield of 46.0 g L−1 h−1 without purifications or acid/base treatments. [ABSTRACT FROM AUTHOR]

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=H3PMo12O40) 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. [ABSTRACT FROM AUTHOR]

Abstract: A highly active and inexpensive Co–Mn mixed‐oxide catalyst was prepared and used for selective oxidation of 5‐hydroxymethylfurfural (HMF) into 2, 5‐furandicarboxylic acid (FDCA). Co–Mn mixed‐oxide catalysts with different Co/Mn molar ratios were prepared through a simple solid‐state grinding method—a low‐cost and green catalyst preparation method. The activity of these catalysts was evaluated for selective aerobic oxidation of HMF into FDCA in water. Excellent HMF conversion (99 %) and FDCA yield (95 % ) were obtained under the best reaction conditions (i.e., 120 °C, 5 h, Co–Mn mixed‐oxide catalyst with a Co/Mn molar ratio of 0.25 calcined at 300 °C (Co‐Mn‐0.25) and 1 MPa O2). The catalyst could be reused five times without a significant decrease in activity. The results demonstrated that the catalytic activity and selectivity of the Co–Mn mixed‐oxide catalysts prepared through solid‐state grinding were superior to the same Co–Mn catalyst prepared through a conventional coprecipitation method. The high catalytic activity of the Co‐Mn‐0.25 catalyst was attributed to its high lattice oxygen mobility and the presence of different valence states of manganese. The high activity and low cost of the Co–Mn mixed‐oxide catalysts prepared by solid‐state grinding make it promising for industrial application for the manufacturing of polyethylene furanoate, a bioreplacement for polyethylene terephthalate, from sustainable bioresources. [ABSTRACT FROM AUTHOR]

Abstract: Several ZrO2‐supported ruthenium catalysts were prepared and utilized in the oxidation of 5‐hydroxymethylfurfural (HMF) to 2,5‐furandicarboxylic acid (FDCA) under base‐free conditions. Full conversion of HMF and almost perfect selectivity towards FDCA (97 %) were achieved after 16 h by using pure O2 as an oxidant and water as a solvent. The catalytic tests show that the size of the Ru particles is crucial for the catalytic performance and that the utilization of high‐surface‐area ZrO2 leads to formation of very small Ru particles. Superior activity was obtained for catalysts based on ZrO2 that had been synthesized by a surface‐casting method and has high surface areas up to 256 m2 g−1. In addition to good activity and selectivity, these catalysts show also high stability and constant activity upon recycling, confirming the suitability of Ru/ZrO2 in the base‐free oxidation of HMF. [ABSTRACT FROM AUTHOR]

ABSTRACT: Two novel bio‐based diamines are synthesized through introduction of renewable 2,5‐furandicarboxylic acid (2,5‐FDCA), and the corresponding aromatic polyimides (PIs) are then prepared by these diamines with commercially available aromatic dianhydrides via two‐step polycondensation. The partially bio‐based PIs possess high glass transition temperatures (Tgs) in the range from 266 to 364 °C, high thermal stability of 5% weight loss temperatures (T5%s) over 420 °C in nitrogen and outstanding mechanical properties with tensile strengths of 79–138 MPa, tensile moduli of 2.5–5.4 GPa, and elongations at break of 3.0–12.3%. Some colorless PI films (PI‐1‐b and PI‐1‐c) with the transmittances at 450 nm over 85% are prepared. The overall properties of 2,5‐FDCA‐based PIs are comparable with petroleum‐based PI derived from isophthalic acid, displaying the potential for development of innovative bio‐based materials. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018, 56, 1058–1066 [ABSTRACT FROM AUTHOR]

ABSTRACT The aim of this study is to investigate the synthesis of 2,5-furandicarboxylic acid (FDCA)-based copolyamides. Indeed, FDCA monomer may be a potential bio-based alternative to phthalic acids. A series of polyamides and copolyamides, PA 6-I( x)/6-F( y), are synthesized in a pilot scale reactor by melt polycondensation of salts based on FDCA, isophthalic acid (IPA), and 1,6-hexamethylenediamine. The chemical structure and composition of the resulting copolymers are extensively characterized by NMR (1H, 13C, and 2D), MALDI-TOF as well as size exclusion chromatography and solution viscosimetry. Their thermal properties are studied by differential scanning calorimetry and TGA and also by a molecular modeling technique. It is pointed out that, during the synthesis, FDCA-rich polymers overcome a massive decarboxylation of FDCA, preventing the production of high molar mass polymers. It is also found that all polymers are amorphous and that the glass transition temperatures decrease as the amount of FDCA in the polymer increases. This is confirmed by the results from molecular dynamics. In addition, it is observed that the copolymers become more hygroscopic when the amount of FDCA in the copolyamides increases. However, the water uptake of PA 6-I( x)/6-F( y) with 90 > x > 50 is lower than those of PA6 and PA 66 polyamides. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45901. [ABSTRACT FROM AUTHOR]

ABSTRACT Cyclic oligo(butylene 2,5-furandicarboxylate) and ɛ-caprolactone were copolymerized in bulk at 130-150 °C by enzymatic ring opening polymerization using CALB as catalyst. Copolyesters within a wide range of compositions were thus synthesized with weight-average molecular weights between 20,000 and 50,000, the highest values being obtained for equimolar or nearly equimolar contents in the two components. The copolyesters consisted of a blocky distribution of the ɛ-oxycaproate (CL) and butylene furanoate (BF) units that could be further randomized by heating treatment. The thermal stability of these copolyesters was comparable to those of the parent homopolyesters (PBF and PCL), and they all showed crystallinity in more or less degree depending on composition. Their melting and glass-transition temperatures were ranging between those of PBF and PCL with values increasing almost linearly with the content in BF units. The ability of these copolyesters for crystallizing from the melt was evaluated by comparative isothermal crystallization and found to be favored by the presence of flexible ɛ-oxycaproate blocks. These copolyesters are essentially insensitive to hydrolysis in neutral aqueous medium but they became noticeably degraded by lipases in an extend that increased with the content in CL units. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018, 56, 290-299 [ABSTRACT FROM AUTHOR]

Abstract: An effective and selective method for the oxidation of 5‐hydroxymethylfurfural (HMF) by using hydrogen peroxide (H2O2) as the liquid oxygen source and activated‐carbon‐supported ruthenium (Ru/AC) as the catalyst was developed. This reaction system allowed HMF to be oxidized in water under mild reaction conditions efficiently, as it was shown to have lower mass‐transfer resistance than gaseous oxygen‐assisted oxidation systems. In addition, we could selectively control the components of the oxidation products by adjusting the reaction conditions. We optimized several reaction parameters such as the reaction temperature (75 °C), time (t=1 or 6 h), base additive (sodium carbonate), and the HMF/catalyst ratio (50 or 10) to attain the desired products in maximum yields. Thus, 5‐formyl‐2‐furoic acid was obtained in a high yield up to 92 % with a HMF/catalyst ratio of 50 and a reaction time of 1 h, whereas 2,5‐furandicarboxylic acid was obtained in a maximum yield of 91.3 % with a HMF/catalyst ratio of 10 and a reaction time of 6 h. A possible mechanism for the selective oxidation of HMF was also discussed. We envision that the H2O2‐mediated oxidation systems proposed in this study would be of great benefit to other organic oxidation systems. [ABSTRACT FROM AUTHOR]

ABSTRACT The bio-based polyester, poly(ethylene 2,5-furandicarboxylate) (PEF), was modified by 2,2,4,4-tetramethyl-1,3-cyclobutanediol (CBDO) via copolymerization and a series of copolyesters poly(ethylene-co-2,2,4,4-tetramethyl-1,3-cyclobutanediol 2,5-furandicarboxylate)s (PETFs) were prepared. After their chemical structures and sequence distribution were confirmed by nuclear magnetic resonance (1H-NMR and 13C-NMR), their thermal, mechanical, and gas barrier properties were investigated in detail. Results showed that when the content of CBDO unit in the copolyesters was increased up to 10 mol%, the completely amorphous copolyesters with good transparency could be obtained. In addition, with the increasing content of CBDO units in the copolyesters, the glass transition temperature was increased from 88.9 °C for PET to 94.3 °C for PETF-23 and the tensile modulus was increased from 3000 MPa for PEF to 3500 MPa for PETF-23. The barrier properties study demonstrated that although the introduction of CBDO units would increase the O2 and CO2 permeability of PEF slightly, PECF-10 still showed better or similar barrier properties compared with those of PEN and PEI. In one word, the modified PEF copolyesters exhibited better mechanical properties, higher glass transition temperature, good barrier properties, and better clarity. They have great potential to be the bio-based alternative to the popular petroleum-based poly(ethylene terephthalate) (PET) when used as the beverage packaging materials. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017, 55, 3298-3307 [ABSTRACT FROM AUTHOR]

The search for new polymers from renewable origin is a sparkling field in polymer chemistry, especially those having promising properties, for example, in terms of their thermal performance. In this vein, in this study, an original renewable 2,5-furandicarboxylic acid-based cycloaliphatic homopolyester, poly(1,4-cyclohexylene 2,5-furandicarboxylate) (PCdF), is synthesized from dimethyl-2,5-furandicarboxylate and 1,4-cyclohexanediol. Poly(1,4-cyclohexanedimethylene 2,5-furandicarboxylate) is also prepared for comparison purposes, since it is the direct renewable substitute of poly(1,4-cyclohexanedimethylene terephthalate) and they are structurally related. The resulting homopolyesters are characterized in detail by using attenuated total reflectance Fourier transform infrared, 1H, 13C and 2D NMR, X-ray and elemental analysis, and thermal properties are assessed by thermogravimetric analysis, differential scanning calorimetry, and dynamic mechanical thermal analysis. PCdF shows to have a semicrystalline character, exhibiting an extremely high glass transition temperature around 175 °C. Moreover, this polyester also shows to be a high thermally stable material with a degradation temperature of 380.0 °C. [ABSTRACT FROM AUTHOR]