Production Of 5-hydroxymethylfurfural Research Articles

Unveiling the Gold Facet Effect in Selective Oxidation of 5-Hydroxymethylfurfural and Hydrogen Production.

Direct oxidation of 5-hydroxymethylfurfural (HMF) to 5-hydroxymethyl-2-furancarboxylic acid (HMFCA), crucial for medical supply production, is hindered by overoxidation. We synthesized gold nanomaterials with distinct single-crystal facets, {111} in octahedra (OC), {100} in nanocubes (NCs), and {110} in rhombic dodecahedra (RD), to investigate the facet-dependent HMF oxidation. The Au RD achieved the spontaneous oxidation of HMF to HMFCA with stoichiometric hydrogen production, maintaining 95% carbon balance, 91% yield, and 98% selectivity. In contrast, Au OC and NCs were inert. The superior performance is due to the absence of a C-H activation energy barrier on the Au(110) facet. Furthermore, gas chromatography and isotope experiments supported that the intermediate is oxidized to produce H2 via H- transfer, rather than H2O via H+ transfer. Oxygen was essential for scavenging electrons, thereby closing the reaction loop. The Au RD exhibited remarkable stability, operating for 240 h without performance degradation, indicating its potential for efficient HMFCA production.

Phase Effects in Zirconia Catalysed Glucose Conversion to 5-(Hydroxymethyl)furfural.

5-(hydroxymethyl)furfural (HMF) is a key biomass derived platform chemical used to produce fuel precursors or additives and value-added chemicals, synthesised by the cascade isomerisation of glucose and subsequent dehydration of reactively formed fructose to HMF over Lewis and Bronsted acid catalysts, respectively. Zirconia is a promising catalyst for such reactions; however, the impact of acid properties of different zirconia phases is poorly understood. In this work, we unravel the role of the zirconia crystalline phase in glucose isomerisation and fructose dehydration to HMF. The Lewis acidic monoclinic phase of zirconia is revealed to preferentially facilitate glucose isomerisation, while the nanoparticulate tetragonal phase possesses Brønsted acid sites which favour fructose dehydration. Synergy between both zirconia phases facilitates cascade HMF production, with both catalysts investigated as physical mixtures in batch and flow reactor configurations. Using a physical mixture of only 15 wt % m-ZrO2 with 85 wt % t-ZrO2 in either batch or packed bed reactor configuration is sufficient to reach equilibrium conversion of glucose for subsequent dehydration by the t-ZrO2 component. Under continuous flow, a six-fold increase in HMF production was obtained when operating with a physical mixture of m- and t-ZrO2 compared to that from a single bed of t-ZrO2.

Valorization of White Lupin Straw Through Mild Dilute Acid Hydrothermal Treatment: A Sustainable Route for Monosaccharide and 5-Hydroxymethylfurfural Production

This study investigates the potential use of white lupine straw (WLS), an underutilized agricultural by-product, as a raw material to produce valuable biochemicals such as monosaccharides and 5-hydroxymethylfurfural (5-HMF) through hydrothermal pretreatment. The aim was to optimize mild reaction conditions to maximize the recovery of these products while minimizing degradation. The hydrothermal treatment of WLS in subcritical water with trace amounts of sulfuric acid was performed, followed by a two-step approach to evaluate the yields of hemicellulose and 5-HMF. The highest monosaccharide yield (163 g/kg) was achieved at temperatures between 174 and 181 °C and a holding time of 7–14 min, while the 5-HMF production was 139.9 g/kg at 199–203 °C and after 0.5–4.5 min. These results suggest that optimal 5-HMF production also increases the remaining solid residue. This study highlights the feasibility of WLS as a sustainable, low-cost biomass resource. It highlights the balance between temperature and time to maximize valuable product yields. The results contribute to advancing biorefinery processes by demonstrating that WLS can be effectively converted into bioethanol precursors and industrial chemicals, supporting circular bioeconomy principles and providing an environmentally friendly alternative to burning crop residues.

Hydroxymethylfurfural(HMF): Exploring its potential as a wood resin derived from cellulose

As the demand for sustainable materials continues to rise, the development of innovative and renewable resins has become a central area of research. This study explores the creation of hydroxymethylfurfural (HMF) resin derived from cellulosic glucose extracted from finely powdered greens and fruit peels. Characterization of HMF was performed using NMR and FTIR-ATR, confirming the presence of HMF. The crude HMF resin underwent purification through crystallization, resulting in an increased conversion efficiency from 51 % to 92 %. The resin displayed high moisture resistance and enhanced bond strength in HMF/wood composites when subjected to boiling water. Morphological analysis revealed an absence of voids, and the HMF/wood composite exhibited a notable tensile strength of 21.5 MPa, comparable to other phenolic composites. The novelty of this work lies in the use of sustainable, powdered waste greens and fruit peels low-cost biomass sources for HMF production, offering a promising renewable alternative to traditional synthetic resins with improved performance characteristics.

Hydrolysis of Babool wood biomass using carbocation scavengers assisted ionic liquid pretreatment for the production of sugars and furfurals

The present study highlights the performance of carbocation scavengers for the pretreatment of hardwood biomass followed by the production of bio-based products. The behaviour of different carbocation scavengers namely; 2-Napthol, 4 Hydroxybenzoic acid, Vanillic acid, Catechol, Hydroquinone, Resorcinol and Phenol and their mitigating effect on the rate of hydrolysis was explored under different operating conditions. All the carbocation scavengers show significant changes in the crystallinity index leading to distinct morphological and physiochemical changes in the biomass structure. Results revealed that the addition of carbocation scavengers not only reduces the inhibitory effect of structured lignin but also enhances the accessibility of cellulose and hemicellulose and facilitates the production of sugars and 5-Hydroxymethyl Furfural. Maximum 5-HMF yield was observed using 2-Napthol at an optimised concentration of 2 wt% (1.5 mL) at 190 °C in 60 min. Further, to evaluate the effect of acetyl groups, biomass deacetylation was also performed. The highest deacetylation effect was observed at 170 °C and showed ∼73% and ∼94% reduction in the holocellulosic content in 60 min. The proposed study develops a sustainable and viable route to suppress the inhibitory effect of lignin with the utilization of carbocation scavengers and enhances biomass digestibility that favours the production of bio-based chemicals.

Unveiling kinetics post rate-determining step in Brønsted acid-catalyzed reactions of fructose: A strategy for 5-hydroxymethylfurfural production from concentrated feedstock

The development of high-yielding catalytic systems is pivotal in biomass upgrading. However, the investigation of kinetics in these complex reaction systems is often highly challenging, especially when reactions leading to byproduct formation are obscured by a preceding, slow rate-determining step. In this work, we introduce a unique approach to kinetic analysis that enables the investigation of reactions occurring post rate-determining step. The technique was applied to the conversion of sugars to 5-hydroxymethylfurfural (HMF), an important platform molecule for sustainable chemical production. First, screening experiments were carried out to identify a catalytic solvent system that achieves a balance between solvent stability, HMF yield, and cost-effectiveness. Our kinetic analysis on the identified system reveals that the fructose reactant undergoes a rate-determining dehydration step to form an unstable reactive intermediate. This intermediate further reacts competitively with other reactive species, such as the hexose reactants or the HMF product, ultimately lowering the HMF selectivity. The calculated relative activation energies of these reactions post rate-determining step provide intuitive insights into the effects of temperature, co-existing reactive species, as well as the previously unexplained effect of feed concentration on HMF selectivity. Additionally, we propose a novel reaction strategy that significantly enhances HMF yield when compared to a traditional batch synthesis. Notably, a high HMF yield of 74 % was achieved with an extreme 55 wt% fructose loading on an aqueous basis (20 wt% loading on a total weight basis) in a low-boiling 80 wt% dioxane/water mixture using an HCl catalyst at 393 K.

Sn-modified SBA-15 with tailored acid properties for efficient 5-hydroxymethylfurfural production from glucose

Interest in production and utilization of 5-hydroxymethylfurfural (5-HMF) has risen greatly as 5-HMF is considered as an extremely important platform compound. It remains a huge challenge to develop efficient and low-cost solid catalysts with suitable acid properties for sustainable production of 5-HMF from glucose. Herein, a bifunctional Sn-modified SBA-15 (Sn–OH/SBA-15) catalyst containing both Lewis and Brønsted acid sites was fabricated. Dimethyldichlorostannane was grafted onto mesoporous SBA-15, and the methyl groups were then converted to hydroxyl groups by calcination. The synergistic effects of Lewis and Brønsted acid significantly boosted the synthesis of 5-HMF from glucose adopting the one-pot method. By optimizing the reaction conditions, the Sn–OH/SBA-15 sample was able to achieve a glucose conversion of 96.9% with a 5-HMF yield of 70.6% (180 °C, 5 h). Moreover, the catalyst demonstrated superior recyclability and reusability. This work would enlighten the exploitation and preparation of highly efficient catalysts for the transformation of carbohydrates into value-added chemicals.

Regioselectivity and confinement effects for catalytic conversion of carbohydrates within zeolite H-BEA

Zeolites have established the importance during biomass conversion, and H-form zeolites, although extensively used, produce hydroxymethylfurfural (HMF) with low yields. Herein, dispersion-corrected density functional calculations are employed with aim to comprehensively understand glucose conversion to HMF within zeolite H-BEA and unravel the role of confinement effects. The low HMF yields originate from regioselectivity: The preferentially activated O3 and O6 sites are significantly driven to humin precursors, while less reactive O1 and O2 sites lead favorably to HMF. Glucose-to-fructose isomerization occurs only at O5 site, while seems unnecessary for HMF production. Owing to the peculiar confinement effects, HMF precursors are prone to emerge within H-BEA, both upon dehydration and during catalysis, while may turn to be acyclic within aqueous solutions. Direct conversion to levulinic acid without HMF as intermediate thus becomes difficult within acidic zeolites. Results facilitate catalyst design for biomass conversion, and further understanding of regioselective catalysis and confinement effects.

A Closed-Loop Biorefinery Approach for the Valorization of Winery Waste: The Production of Iron-Sulfonated Magnetic Biochar Catalysts and 5-Hydroxymethyl Furfural from Grape Pomace and Stalks

In this work, a closed-loop strategy for the management and valorization of winery waste was proposed. The exhausted pomace and grape stalks that are typically obtained from white wine industries were used as a source of simple sugars, namely, glucose and fructose, and of lignocellulosic feedstock for the preparation of selective catalysts for the 5-hydroxymethylfurfural (5-HMF) production from fructose. A novel synthetic procedure was developed for the synthesis of iron-sulfonated magnetic biochar catalysts (Fe-SMBCs). Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), BET surface area, porous structure analysis and determination of total amount of acid sites were performed in order to characterize the physico-chemical properties of the synthesized systems. Then, these heterogeneous catalysts were successfully tested via the dehydration of simple sugars into 5-HMF by using methyl isobutyl ketone (MIBK) and gamma valerolactone (GVL) as co-solvents. The optimum 5-HMF yield of 40.9 ± 1.1%mol with a selectivity of 59.8 ± 2.6%mol was achieved by adopting the following optimized conditions: 0.1 g of catalyst, volume ratio of GVL to H2O = 2 to 1, 403 K, 6 h. In addition, the catalyst was easily recycled using an external magnetic field and used for at least five reaction cycles without significant loss of catalytic activity.

An innovative phosphated Zr[sbnd]Si Laponite as a solid acid catalyst for 5-hydroxymethylfurfural production from fructose

The dehydration of fructose is a crucial chemical process for synthesizing valuable chemicals and biofuels. This work explored an attractive strategy for harnessing lignocellulosic biomass through the catalytic conversion of fructose, yielding valuable 5–hydroxymethylfurfural (HMF) chemicals and biofuels. Sustainable and cost–effective methodologies for crafting catalysts via Laponite (Lap) modification to facilitate fructose transformation into HMF within a biphasic system comprising aqueous NaCl and tetrahydrofuran (THF) were examined. The phosphated Zr–grafted Si–enriched Lap (P/Zr–SiLap), as a solid acid catalyst, was synthesized through multiple straightforward steps involving mesoporous silica formation, Zr atom incorporation, and phosphation of pristine Lap. The P/Zr–SiLap catalyst proved to be a most promising catalyst, achieving an optimized HMF yield of 78.4% at 150 °C with a turnover frequency (TOF) for HMF production of 2.8 × 10−5 h−1. Evaluation of the P/Zr–SiLap demonstrated the catalyst's robust endurance, ensuring its high potential for efficient recyclability. The enhanced HMF yield (%) attributable to the P/Zr–SiLap catalyst was systematically correlated with its structure–activity relationship, which was elucidated through various advanced analytical techniques.

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.

Optimizing 5-hydroxymethylfurfural production from biomass carbohydrates: ionic liquid-catalyzed pathways in deep eutectic solvents under sonication and thermal conditions

The synthesis of ionic liquid (IL)-based mesopore SBA-16 catalyst for the conversion of biomass-derived carbohydrates into 5-hydroxymethylfurfural (5-HMF) in the presence of 15 deep eutectic solvents (DESs) under sonication and thermal conditions.

Polystyrene-based catalysts with simultaneous Brønsted and Lewis acidity for hydroxymethylfurfural production from starch: molecular weight and solvent effects

Soluble and reusable polystyrene-based catalysts with Brønsted and Lewis acidity allowed the one-pot synthesis of hydroxymethylfurfural (HMF) from potato starch.

Diastase Enzyme activity and Hydroxymethylfurfural production during thermal processing of honey

The thermal treatment of honey is used to prevent honey crystallization which is one of the main problems that face beekeepers. In this study three samples of honey were heated at 40, 60, 80 and 100 °C, as a function of time in hours (h). Heating the samples at 40 °C did not show any significant effect on hydroxymethylfurfural (HMF) production or diastase enzyme activity up to 95 hours. Heating to higher temperatures 60, 80 and 100 °C resulted in a regular increase in HMF content and drop-off in diastase activity as a function of time. The HMF content reached 40 mg/kg after 80, 12.5 and 6 hours. For the three samples at 60, 80 and 100 °C respectively. Conversely, diastase enzyme activity reached close to 8 IU after 96, 12.5 and 5 hours. For the following temperatures 60, 80 and 100 °C respectively. The results showed that heating temperatures up to 40 °C is safe for long-term storage, while heating at 60 °C could be used but for a shorter treatment time. Results showed that the must temperature does not exceed 60 °C for 5 hours or 80 °C for one hour to preserve the honey's quality. The reaction rate constants and activation energy Ea of HMF formation in three samples were found 83.07, 91.79 and 89.57 kJ.mol-1 respectively. Therefore, honey can be preserved in this way, while at the same time the HMF remains below the permissible values, and the enzymatic activity remains at its highest level.

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.

One-pot Conversion of Sago Pith Waste (SPW) into 5-Hydroxymethyl Furfural (HMF)

Hydroxymethyl furfural (HMF) is widely understood to be a robust substitute feedstock for a wide array of petroleum-derived products such as plastic and fuel. Previous research delved into the use of waste (i.e., biomass) to produce HMF. These waste products stemmed from sugarcane bagasse, algae, bread, and banana. Our study is the first to report the use of sago pith waste (SPW), a by-product of the sago starch industry, for HMF production via simultaneous conversion in one pot. The production of HMF in such a manner not only yields an industrially important product (i.e., HMF) but also confers a sustainable waste management solution to the sago starch industry. SPW primarily consists of starch and fiber, and since the density of SPW affects the feed rate of the reactor, it is necessary to optimize the reaction temperature, sample volume, and amount of activated carbon to elucidate reaction conditions with a high HMF yield. By adding activated carbon and sodium chloride into the reaction mixture with a Bronsted-Lewis acid, we obtained 50-60% mole of HMF from SPW in a simultaneous reactor system at 160°C for 8 minutes.

Impact of Porous Silica Nanosphere Architectures on the Catalytic Performance of Supported Sulphonic Acid Sites for Fructose Dehydration to 5-Hydroxymethylfurfural.

5-hydroxymethylfurfural represents a key chemical in the drive towards a sustainable circular economy within the chemical industry. The final step in 5-hydroxymethylfurfural production is the acid catalysed dehydration of fructose, for which supported organoacids are excellent potential catalyst candidates. Here we report a range of solid acid catalysis based on sulphonic acid grafted onto different porous silica nanosphere architectures, as confirmed by TEM, N2 porosimetry, XPS and ATR-IR. All four catalysts display enhanced active site normalised activity and productivity, relative to alternative silica supported equivalent systems in the literature, with in-pore diffusion of both substrate and product key to both performance and humin formation pathway. An increase in-pore diffusion coefficient of 5-hydroxymethylfurfural within wormlike and stellate structures results in optimal productivity. In contrast, poor diffusion within a raspberry-like morphology decreases rates of 5-hydroxymethylfurfural production and increases its consumption within humin formation.

Kinetic Modeling of Cornstalk Cellulose Hydrolysis in Supercritical Water: A Comparative Study of the Effects of Temperature and Residence Time on Derivative Production

Kinetic modeling is essential in understanding and controlling the process of cellulose hydrolysis for producing value-added cellulose derivatives. This study aims to adopt a set of dominate kinetic ordinary differential equations of cornstalk cellulose hydrolysis in supercritical water for mechanism-based prediction of the production of cellulose, glucose, fructose, glyceraldehyde, erythrose, 5-hydroxymethyl furfural, glycolaldehyde, threose, aldose, and other cellulose derivatives from cornstalks under processing conditions with a pressure of 89 MPa and a temperature of 378 °C, as considered in a recent experimental study in the literature. The yield rates of several cellulose derivatives, e.g., glucose, fructose, 5-HMF, and erythrose as predicted by the present model, are close to those of experimental measurements. The model is further used to predict the yield rates of a few new cellulose derivatives, e.g., glycolaldehyde, threose, and aldose, that are potentially generated in cornstalk cellulose hydrolysis in supercritical water. The present model and computational simulations can be utilized as a rational tool to predict, control, and optimize the derivative yields in cellulose hydrolysis in supercritical water via tuning the process parameters, and, therefore, are useful for the optimal production of targeted bio-based fuels and chemicals from cornstalks and other agricultural and municipal wastes.