HMF Production Research Articles

Defective MIL-53(Al)-NH2: A bifunctional Lewis-Brønsted acid catalyst for efficient 5-HMF production from glucose

Developing functional catalysts with both Lewis and Brønsted acid sites is an essential task for achieving the direct conversion of glucose to 5-hydroxymethylfurfural (5-HMF), a process that is crucial for the sustainable production of renewable fuels and chemicals. In this work, a mixed-linker strategy is proposed to prepare defective MIL-53(Al)-NH2 by introducing trifluoroacetic acid into the MIL-53(Al)-NH2 synthesis process. The creation of defects facilitates the exposure and accessibility of Al3+ centers, as well as changes the coordination environment within the MIL-53(Al)-NH2 skeleton. Both the number of Lewis and Brønsted acid sites are boosted, which is beneficial for glucose activation and 5-HMF generation. Through optimizing the reaction conditions, a glucose conversion of 98.3 % with a 5-HMF yield of 59.3 % was achieved by using defective 6d-MIL-53(Al)-NH2 in a biphasic tetrahydrofuran/H2ONaCl system. Moreover, the 6d-MIL-53(Al)-NH2 catalyst showed excellent recyclability and reusability, with its catalytic efficiency maintained almost unchanged for consecutive 10 cycles. The catalytic mechanism was elucidated and the acidity of the Lewis and Brønsted acid was modulated by defect engineering to achieve exceptional performance.

Silicotungstic acid catalyst supported onto functionalized halloysite nanotubes (HNTs) utilized for the production of 5-hydroxymethylfurfural (5-HMF) from fructose

5-Hydroxymethylfurfural (5-HMF) is a valuable organic compound commonly derived from sugars such as fructose and glucose. Silicotungstic acid (HSiW), a unique Keggin-type heteropolyacid, is a typical catalyst for organic compound production. To synthesize 5-HMF from fructose, we developed a novel catalyst, HSiW@F-HNTs, by combining HSiW and functionalized halloysite nanotubes (F-HNTs) modified with (3-amino-propyl) triethoxysilane (APTES), 2,4,6-trichloro-1,3,5-triazine (TCT), and l-arginine. We analyzed the physicochemical properties of HSiW@F-HNTs using the FT-IR, XRD, BET, FESEM, EDS, and XPS characterization techniques, confirming their suitability for fructose-to-5-HMF conversion. Through response surface methodology (RSM), we investigated and optimized the effects of reaction conditions on 5-HMF production yield. Optimal conditions were found to be a 102 °C reaction temperature, a 65 min reaction time, and an 8.5 wt.% catalyst loading, resulting in a 95 % yield of fructose-to-5-HMF conversion. We also conducted the kinetic and thermodynamic analyses to determine the reaction rate and activation energy (Ea) and estimate the changes in Gibbs free energy (ΔG), enthalpy (ΔH), and entropy (ΔS) of the catalytic conversion reaction. Additionally, the prepared HSiW@F-HNTs catalyst could be recycled up to 9 times without a significant loss in activity, demonstrating its high stability for real-world applications.

One-pot direct conversion of passion fruit hull into 5‑hydroxymethylfurfural catalysed by halogenated metal ionic liquids and organic acids

Biomass serves as a crucial source of renewable energy and potential raw materials for synthesizing various value-added chemicals. This study explored the direct conversion of the cellulose of passion fruit shells into 5-hydroxymethylfurfural (5-HMF), a promising substitute for fossil-derived compounds, by combining halogenated metal ionic liquids (ILs) and organic acids through one-pot hydrothermal reaction. Factors such as the type of ILs and organic acids, reaction time and temperature, as well as the quantity of dimethyl sulfoxide (DMSO) in the solvent, and the loading of substrate, IL, and organic acid were investigated for their impact on 5-HMF yield. Optimization of reaction conditions led to the attainment of the highest 5-HMF yield, reaching 33.1 ± 0.34 % based on the cellulose content within the passion fruit shell. Furthermore, the structural and morphological changes of the solid residues were analysed through techniques such as Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). These analyses revealed the progressive conversion of cellulose, hemicellulose, and lignin, accompanied by the formation of humin by-products. This integrated approach for 5-HMF production from agricultural waste introduced novel possibilities for transforming sustainable biomass resources into valuable chemical products.

Reactor development for a one‐step hybrid catalytic conversion of D‐glucose to HMF

AbstractThe design of an “H”‐shaped reactor has been studied to satisfy the possibility of using a triphasic medium to transform d‐glucose into 5‐hydroxymethylfurfural (HMF) by a hybrid catalytic process using an immobilized glucose isomerase, allowing the isomerization of D‐glucose to d‐fructose, and a heterogeneous chemical catalyst to catalyze the dehydration of d‐fructose to HMF. The various parameters influencing the transport of d‐fructose within the reactor were studied, namely the difference in pH between the two aqueous phases, the agitation and the quantity of 3,4‐DCPBA/Aliquat336® used to extract and transport continuously the d‐fructose. The pH discrepancy, which must be between 5.0 and 5.5, turns out to be the real driving force behind the extraction of D‐fructose. The D‐Fru/3,4‐DCPBA molar ratio of 1/0.25 allowed the transport of more than 80 % of the D‐fructose initially present and shows that the same molecule of 3,4‐DCPBA is involved at least twice in the transport of D‐fructose and that the 3,4‐DCPBA/Aliquat336® couple performs a turnover within the organic phase. Finally, a HMF production yield of 30.9 % and an isomerization yield of 79.1 % were obtained, illustrating the shift in the isomerization equilibrium made possible by a D‐fructose extraction yield of 96.8 %.

Environmental impact of 5-hydroxymethylfurfural production from cellulosic sugars using biochar-based acid catalyst

In this study, HMF was successfully synthesized from a range of cellulosic sugars, utilizing sustainable acidic biochar derived from cassava rhizome (CR). Various acid precursors such as sulfuric acid (H2SO4),p-toluenesulfonic acid (TsOH), and ferric chloride (FeCl3) were chosen. Acids grafted biochar were carried out through a facile hydrothermal method. HMF production was performed at 175 °C for 0.5 h using 10 % of the acidic biochar catalyst in water to isopropanol (i-PrOH) mixture ratio of 1:4. The maximum HMF yields of fructose (53.29 wt%), glucose (2.94 wt%), and cellulose (0.38 wt%) could be achieved over 600-H2SO4, 700-FeCl3, and 400-H2SO4catalysts, respectively. Moreover, the recyclability of the acidic biochar catalysts could distinguish more than five times without significant loss of activity. Remarkably, the life cycle assessment (LCA) and cost analysis of the HMF production process indicated that the future sustainable industrial production of HMF could be realizedinvolving the 600-TsOH catalyst.

The possibility of chemical transformation of glucose in choline chloride/glucose deep eutectic solvent with thermal instability.

Deep eutectic solvents (DESs), characterized by their low volatility, non-toxicity, and biodegradability, have gained attention as green solvents due to their minimal environmental impact and sustainability. The choline chloride/glucose DES, composed solely of biomass, is notable for its high biocompatibility and ability to be prepared at low cost. However, it is also known for its low thermal stability and tendency to denature when heated. In this study, we approached the choline chloride/glucose DES, with its thermal denaturation properties, as a unique chemical conversion medium entirely constituted from biomass. We investigated the thermal denaturation and reaction behaviors of the DES when subjected to prolonged heating. It was found that the choline chloride/glucose DES was relatively thermally stable at around 100 °C, but underwent thermal denaturation at 130 °C, enabling the production of 5-HMF and seven types of rare sugars derived from glucose. The yield of disaccharides containing seven types of rare sugars and 5-HMF relative to the weight of glucose was as high as approximately 70% and 5%, respectively. This study thus reveals that simply heating a liquid composed exclusively of biomass under mild conditions can generate a range of high-value compounds.

Computational insights into selective glucose to 5-hydroxymethylfurfural (HMF) conversion by reducing humins formation in aqueous media under Brønsted acid-catalyzed conditions.

5-Hydroxymethylfurfural (HMF) is known for its potential in biofuel production and as a platform chemical for many commercially important molecules. The cost-effective large-scale production of HMF from glucose is hampered by its poor yield in aqueous media due to the formation of polymeric side products known as humins. Thus, reducing humins formation is a strategy for the efficient conversion of glucose to HMF. However, the origin of humins formation and their structures are elusive. In this regard, we investigated the polymerization mechanism and the structure of humins formed during the Brønsted-acid-catalyzed dehydration of glucose to HMF in an aqueous medium by employing density functional theory-based calculations and microkinetic analyses. Notably, the results of this work indicate that humins formation occurs only after the formation of HMF in the reaction mixture and the major part of the humins structure (about 60%) is composed of furanic rings. Furthermore, based on the knowledge gained from in-depth mechanistic and microkinetic studies, potential strategies to reduce humins formation and thereby enhance HMF selectivity are proposed here.

Economic and environmental sustainability of bio-based HMF production and recovery from lignocellulosic biomass

Transforming waste stream of biorefinery into high-value bioproducts.

Designed synthesis N-doped sulfonated bifunctional catalyst for efficient 5-hydroxymethylfurfural production: A pyridinic N-triggered proton-shift mechanism at basic sites

Considering the essential role of acidic/basic sites in efficient 5-hydroxymentylfurfural (5-HMF) production from cellulose, the superiority of acid-base bifunctional catalysts was unfolded. However, the lack of in-depth research on catalytic mechanism of active sites, especially the basic sites, greatly hinders its chemical utilization. Herein, N-doped sulfonated bifunctional catalysts were rationally designed. The synthesized NCS-1H catalyst exhibited outstanding activity and recyclability. Favorable 5-HMF yield of 50.0 % with 62.9 % of selectivity was obtained. Spin polarized density function theory (DFT) analysis revealed a pyridinic N-triggered proton-shift mechanism of glucose isomerization. Catalyzed by pyridinic N, the proton of glucose on C2 was shifted to O5, leading to the cleavage of C1-O1 bond. As a result, an enol intermediate was formed and converted to fructose. Compared to pyrrolic N and graphitic N, pyridinic N significantly reduced the reaction energy barrier of rate-determining step to 0.79 eV, i.e., C1-O1 bond cleavage.

Valorization of beverage waste as a sugar source for 5-hydroxymethylfurfural production

This study highlights the valorization of beverage waste as a promising sugar-based raw material for 5-hydroxymethylfurfural (5-HMF) production. In this work, both beverage waste purification and 5-HMF production were experimentally demonstrated through the practicality and effectiveness of continuous-flow processes. In the purification process, solid and liquid impurities were wholly eliminated through membrane filtration and a two-stage adsorption process using activated carbon. The purified beverage waste primarily consisted of fructose, glucose, and sucrose, offering a plentiful source of sugar. A mini fixed-bed reactor was employed to thoroughly investigate the impact of various operating variables on continuous 5-HMF production from synthetic beverage waste. The variables considered included residence time, reaction temperature, catalyst type, solvent type, water content, and sugar concentration. The optimization analysis was conducted to achieve both high 5-HMF yield and productivity. The optimal condition, which resulted in the 5-HMF yield of 42.6% and productivity of 3.3e−3 kg5-HMF/kgcat-h, was obtained with a residence time of 15 min, sugar feed concentration of 10 g/L, reaction temperature of 120 °C, and water content of 10 g/L. Dimethyl sulfoxide (DMSO) and Amberlyst 15 were the selected solvent and catalyst, respectively. The feasibility of producing 5-HMF from actual beverage waste was validated under optimal conditions. Furthermore, the stability of the catalyst was demonstrated over 24 h of time-on-stream. The proposed processes offer the potential for continuous purification of beverage waste and the efficient production of 5-HMF.

Enhanced 5-hydroxymethylfurfural production from cellulose in monophasic molten salt hydrate: Insights into the effect of catalyst acidity on conversion

Production of 5-HMF from cellulose is a promising approach for advanced bio-fuels preparation, but the degradation of active 5-hydroxymethylfurfural (5-HMF) is a critical challenge affecting 5-HMF selectivity. To address this issue, biphasic reaction system consisting of water and organic solvent is generally used to in-situ extract 5-HMF into organic phase to inhibit product degradation. Despite the high 5-HMF selectivity achieved in biphasic system, low product concentration and difficulty in separation restrict its industrial applications. Molten salt hydrate (MSH) is unique in cellulose conversion and 5-HMF preservation. In this work, MSH of LiBr was used as monophasic solvent for cellulose conversion and an acidity tunable solid acid AlSiO-x was used as the catalyst. It was found that a relatively high 5-HMF yield of 44.5% together with carbon balance of 75.0% were obtained at 170 °C for 20 min, which is higher than the results ever reported. Importantly, this work proved that the ratio of total Brønsted to Lewis acid sites on solid acid is the key issue affected 5-HMF yield. After reaction, solid acid can be recycled for more than 5 times without catalytic performance decline, and the dissolved 5-HMF can be sufficiently separated from MSH via hyper cross-linked polymer (HCP) adsorption.

Two birds with one stone: A magneto-optical dual-stimuli-responsive intelligent Pickering emulsion for efficient conversion of glucose to 5-hydroxymethylfurfural

The efficient conversion of glucose to 5-hydroxymethylfurfural (HMF) is a critical process for maximizing the value of lignocellulosic biomass. However, the existing systems of binary solvent and ionic liquids (ILs) commonly employed for this conversion often encounter significant interphase mass transfer resistance and exhibit lower utilization efficiency of ILs. Herein, the study presents the precise fabrication of a novel Pickering interfacial catalyst, P(0.8[CL8]-[ILs]2-[SP])@SiO2@Fe3O4 with immobilized magneto-optical bi-sensitizer and Brønsted&di-superimposed-Lewis acid functionalized ILs (B-L-ILs), realized through surface-initiated reversible addition-fragmentation chain transfer polymerization. The construction of an intelligent Pickering emulsion with dual-stimuli-responsive properties was effectively accomplished by accurate manipulation under Vis-light radiation, utilizing P(0.8[CL8]-[ILs]2-[SP])@SiO2@Fe3O4. The presence of this emulsion significantly enhances interphase mass transfer in a binary solvent system, while the incorporation of B-L-ILs at interphase interfaces in Pickering emulsion greatly facilitates the efficient conversion of glucose to HMF. The Pickering interfacial catalyst demonstrates exceptional and unprecedented performance, as evidenced by its ability to achieve a glucose conversion rate of 96.3% and HMF yield of 86.7%. Various characterizations, experimental analyses, and kinetic studies synergistically confirm the efficient conversion of glucose to HMF in the Pickering emulsion. The effective control of Pickering demulsification can be intelligently achieved by simultaneously applying magnetic stimulation and UV-light irradiation, while its catalytic activity remains unaltered even after undergoing five consecutive cycles. This study presents a novel approach to enhance the efficiency of HMF production by combining a cutting-edge Pickering emulsion with B-L-ILs, thereby accomplishing two objectives simultaneously.

Recent Advances in Zeolites-Catalyzed Biomass Conversion to Hydroxymethylfurfural: The Role of Porosity and Acidity.

Biomass is an attractive raw material for the production of fuel oil and chemical intermediates due to its abundant reserves, low price, easy biodegradability, and renewable use. Hydroxymethylfurfural (5-HMF) is a valuable platform chemically derived from biomass that has gained significant research interest owing to its economic and environmental benefits. In this review, recent advances in biomass catalytic conversion systems for 5-HMF production were examined with a focus on the catalysts selection and feedstocks' impact on the 5-HMF selectivity and yield. Specifically, the potential of zeolite-based catalysts for efficient biomass catalysis was evaluated given their unique pore structure and tunable (Lewis and Brønsted) acidity. The benefits of hierarchical modifications and the interactions between porosity and acidity in zeolites, which are critical factors for the development of green catalytic systems to convert biomass to 5-HMF efficiently, were summarized and assessed. This Review suggests that zeolite-based catalysts hold significant promise in facilitating the sustainable utilization of biomass resources.

Formic acid as a sacrificial agent for byproduct suppression in glucose dehydration to 5-hydroxymethylfurfural using NaY zeolite catalyst

Biomass-derived 5-hydroxymethylfurfural (HMF) holds potential for applications in green materials, but its conventional synthesis is hindered by undesired side reactions. This study presents a catalytic system that effectively suppresses the formation of byproducts, thus enhancing HMF yield. The system demonstrated synergistic effects between Lewis acid NaY zeolite and formic acid sacrificial agent for the production of HMF from glucose. The results indicate that formic acid reacts with reactive intermediates from glucose decomposition, preventing their interactions with other sugar-derived species in the dehydration path to HMF. Such effect originates from the neutral formic acid species rather than the dissociated acidic proton normally observed in Brønsted acid-catalyzed reactions. The NaY/formic acid catalysts in isopropanol/water achieved a 57% HMF yield, a significant improvement over 31% and 27% yields with NaY or formic acid alone, respectively. Moreover, performance of the spent catalysts was easily restored to the original state via a simple NaCl wash.

Current Status and Challenges for Metal-Organic-Framework-Assisted Conversion of Biomass into Value-Added Chemicals.

Owing to the abundance of availability, low cost, and environmental-friendliness, biomass waste could serve as a prospective renewable source for value-added chemicals. Nevertheless, biomass conversion into chemicals is quite challenging due to the heterogeneous nature of biomass waste. Biomass-derived chemicals are appealing sustainable solutions that can reduce the dependency on existing petroleum-based production. Metal-organic frameworks (MOFs)-based catalysts and their composite materials have attracted considerable amounts of interest in biomass conversion applications recently because of their interesting physical and chemical characteristics. Due to their tunability, the catalytic activity and selectivity of MOF-based catalyst/composite materials can be tailored by functionalizing them with a variety of functional groups to enhance biomass conversion efficiency. This review focuses on the catalytic transformation of lignocellulosic biomass into value-added chemicals by employing MOF-based catalyst/composite materials. The main focus is given to the production of the platform chemicals HMF and Furfural from the corresponding (hemi)cellulosic biomass, due to their versatility as intermediates for the production of various biobased chemicals and fuels. The effects of different experimental parameters on the conversion of biomass by MOF-based catalysts are also included. Finally, current challenges and perspectives of biomass conversion into chemicals by MOF-based catalysts are highlighted.

Integrated process towards sustainable renewable plastics: Production of 2,5-furandicarboxylic acid from fructose in a base-free environment

We report an integrated approach to produce 2,5-furandicarboxylic acid (FDCA) using fructose as a feedstock in a base-free environment, thus providing a promising alternative to the current protocol. FDCA, an alternative molecule to terephthalic acid (obtained from the petroleum route), is used to synthesize poly(ethylene-2,5-furanoate) (PEF), a renewable plastic. In our approach, we produced 5-hydroxymethylfurfural (HMF; 84% yield) by fructose dehydration in an acetone (Ace)/H2O solvent system. The obtained HMF feed was subsequently oxidized over Ru/MnO2, producing FDCA in 92% yield under base-free conditions. The Ru/MnO2 catalyst outperformed conventional Pt/C and Ru/C catalysts under identical reaction conditions. Our novel approach for FDCA production via an integrated process using an Ace/H2O solvent mixture under base-free conditions is economically feasible and environmentally friendly. To the best of our knowledge, this work is the first to report the production of FDCA via this route. We postulate that the high catalytic efficiency of the sulfonated porous organic polymer and Ru/MnO2 in an Ace/H2O system renders them superior to existing homogeneous catalytic routes for HMF production and conversion into FDCA via a scalable process.

One-pot conversion of cellulose to HMF under mild conditions through decrystallization and dehydration in dimethyl sulfoxide/tetraethylammonium chloride

As a crucial bio-based platform chemical, the production of 5-hydroxymethylfurfural (HMF) from the abundant substrate cellulose has garnered significant attention. However, tedious reaction steps are inevitable because of the complex tandem conversions of dissolution, hydrolysis, and dehydration. Furthermore, due to the ultralow solubility of cellulose, harsh reaction conditions are inevitable, which can exacerbate HMF degradation. To this end, we investigated the structural changes in microcrystalline cellulose (MCC) after its dissolution and regeneration in various dimethyl sulfoxide (DMSO)/deep eutectic solvents (DESs) to clarify the mechanisms underlying its dissolution. The results revealed that the highly crystalline cellulose I in MCC was converted into amorphous cellulose II after treatment with DMSO/tetraethylammonium chloride (TEAC), which led to the complete dissolution of MCC. Accordingly, a dissolution-catalysis coupling reaction strategy was proposed for converting MCC to HMF via a one-pot method in DMSO/TEAC, simultaneously reducing the number of steps necessary for the reaction and achieving mild reaction conditions. In addition, the pathway for the one-pot reaction was clarified by analyzing the intermediate yields. The combination of AlCl3 as a catalyst and DMSO/TEAC resulted in a notable MCC conversion of 93.3 wt% and a high HMF yield of 53.1%. Remarkably, the reaction conditions employed in this study (130 °C, 1 h) were milder in terms of shorter reaction times and lower temperatures than those reported in most current literature. This was attributed to the complete dissolution of MCC resulting from decrystallization. Therefore, the proposed reaction strategy enabled the efficient production of HMF from cellulose.

Production of 5-hydroxymethylfurfural from apple pomace in deep eutectic solvent

Apple pomace is a waste stream produced by fruit processing industry millions of tons annually. It is rich in carbohydrates making it a potential feedstock for the production of 5-hydroxymethylfurfural (HMF), one of the most valuable platform chemicals. In this work, the conversion of apple pomace carbohydrates to HMF was studied in a choline chloride:glycolic acid (1:3) deep eutectic solvent. To prevent undesired side reactions of HMF methyl isobutyl ketone was added to the reaction system as an extractive phase. The effect of reaction conditions, i.e., the amount of water added to the reaction system, the presence of Lewis acid co-catalyst, as well as the reaction temperature and time, on HMF yield were studied. The highest total HMF yield (44.5%) was achieved at 110 °C in 10 min with 15 wt% H2O, and 0.01 g CrCl3 as co-catalyst. Without the co-catalyst, the highest achieved HMF yield was 37.3% (120 °C, 20 min, 15 m% H2O). The results indicated that apple pomace can be used as the feedstock for HMF production but the reaction procedure, especially the extraction process of HMF from deep eutectic solvent needs to be studied further.Graphical abstract

Catalytic Conversion of Cellulose to 5‐Hydroxymethylfurfural: Advancements in Heterogeneous Catalysts and Cutting‐Edge Hydrolysis Strategies

AbstractThe catalytic conversion of lignocellulose‐derived carbohydrates, particularly cellulose, into 5‐hydroxymethylfurfural (HMF), holds significant potential as a crucial step in the sustainable production of valuable platform chemicals. This review presents the remarkable progress made in the field, with a specific emphasis on the role of heterogeneous catalysts, innovative methods for accelerating cellulose hydrolysis, and the design of flow reactor technologies. The distinctive properties and surface functionalities of catalysts facilitate the efficient breakdown of cellulose's intricate structure, thereby promoting selective hydrolysis leading to HMF formation. Therefore, this review comprehensively examines various categories of heterogeneous catalysts, including metal oxides/phosphates, zeolites, functionalized silica/carbon‐based materials, heteropolyacids (HPAs), and metal‐organic frameworks (MOFs), highlighting their unique mechanisms and performance in cellulose conversion. Furthermore, the review describes the intriguing progress in hydrolysis strategies (pretreatment techniques and advanced heating systems) that have been crucially involved in overcoming the challenges associated with cellulose recalcitrance and achieving enhanced HMF yields. The synergistic interactions between catalysts and innovative hydrolysis methods have played a central role in the breakthroughs within cellulose conversion technology. Another aspect covered in this work is the advancement in using fixed‐/fluidized‐bed reactors and slug microreactors for the continuous production of HMF. Lastly, the current challenges and future perspectives are presented to propose the dilemma and development direction for efficient cellulose‐to‐HMF conversion.

Highly efficient, rapid, and practical conversion of carbohydrate into 5-hydroxymethylfurfural using a continuous-flow reactor with 1-(4-sulfobutyl)-3-methylimidazolium bromide ionic liquid as a catalyst

The application of continuous flow reactors for sustainable chemical research and production has attracted much attention. 5-Hydroxymethylfurfural (5-HMF) has been considered high potential for the production of chemicals and fuels. This work demonstrated the promise of synthesizing 5-HMF with high yield and selectivity using ionic liquids under continuous flow. The effects of temperature, solvent, catalyst activity, catalyst loading, substrate, and large-scale synthesis were investigated to choose the optimal reaction condition. As a result, 1-(4-sulfobutyl)-3-methylimidazolium bromide afforded 5-HMF in the good yield, about 68% in DMSO at 140 °C for 5 min. This approach is not only an eco-friendly pathway but also saves time, which can obtain high efficiency and apply in the large-scale production of 5-HMF from fructose.