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Changes in the amount of 5-hydroxymethylfurfural (5-HMF), a harmful substance, in dried Ganoderma lucidum extract mixtures were investigated in order to find the most suitable drying method. The G. lucidum extract mixtures were processed using the following drying methods: spray, vacuum, infrared, heat pump, hot air, and vacuum freeze-drying. The 5-HMF content under different process parameters was measured. In the case of the spray drying method, the 5-HMF content increased initially and then decreased when the feed rate and air flow were gradually increased. In the vacuum drying method, the increase of drying temperature or material thickness led to an increase in 5-HMF content, and the 5-HMF and moisture content decreased as the vacuum degree increased (P<0.05). The 5-HMF content increased with the increase of temperature in the infrared, heat pump and hot air drying methods. The 5-HMF content of the samples after vacuum freeze-drying was 779.29 mg/kg, and the processing time, 50 h, was the longest of all the drying methods. The 5-HMF and moisture content of the sample obtained by vacuum drying under each optimal scheme were 774.32 mg/kg and 4.97%, respectively, and the processing time, 17 h, was the shortest of all the methods. However, the sample obtained from vacuum drying was dark brown, brittle, and hard, and was not easily redissolved. Considering the content of 5-HMF and drying time, as well as other factors, the vacuum drying method should be preferred, but further measures should be taken to improve the appearance and re-solubility of the product. [ABSTRACT FROM AUTHOR]

BACKGROUND: The conversion of glucose into 5‐hydroxymethylfurfural (5‐HMF) involves the isomerization of glucose to fructose catalyzed by Lewis acid and subsequent dehydration of fructose catalyzed by Brönsted acid. In this work, in order to obtain a high yield of 5‐HMF, a series of Sn‐Al‐Beta catalysts containing both Lewis and Brönsted acid sites were prepared by a convenient solid state ion exchange (SSIE) method using partially dealuminated Beta zeolite and tin(II) acetate. RESULTS: The obtained bifunctional catalysts were investigated for one‐pot production of 5‐HMF from glucose in the ionic liquid (IL) [C4mim]Cl. Among various catalysts, Sn‐Al‐Beta‐4‐8 exhibited the best catalytic performance, giving a 5‐HMF yield of 54% under optimal reaction conditions (393 K, 2 h), along with a glucose conversion of 81%. The Sn‐Al‐Beta‐4‐8 catalyst and IL were regenerated by the extraction of 5‐HMF, and the reactivity was reserved after five runs of recycling. In addition to glucose, the Sn‐Al‐Beta‐4‐8/[C4mim]Cl system was also proven to have the potential to effectively convert other carbohydrates into 5‐HMF. CONCLUSION: The results suggested that the catalyst is convenient to prepare and has preferable efficiency and stability in the conversion of carbohydrates into 5‐HMF. © 2022 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Bioprocess Engineering is the property of Chinese Journal of Bioprocess Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

5-hydroxymethylfurfural (HMF) oxidation in aqueous media using visible photocatalysis is a green and sustainable route for the valorization of lignocellulosic biomass derivatives. Several semiconductors have already been applied for this purpose; however, the use of Poly(heptazine imides), which has high crystallinity and a special cation exchange property that allows the replacement of the cation held between the layers of C3N4 structure by transition metal ions (TM), remains scarce. In this study, PHI(Na) was synthesized using a melamine/NaCl method and used as precursor to prepare metal (Fe, Co, Ni, or Cu)-doped PHI catalysts. The catalysts were tested for selective oxidation of HMF to 2,5-diformylfuran (DFF) in water and O2 atmosphere under blue LED radiation. The catalytic results revealed that the 0.1 wt% PHI(Fe) catalyst is the most efficient photocatalyst while higher Fe loading (1 and 2 wt%) favors the formation of Fe3+ clusters, which are responsible for the drop in HMF oxidation. Moreover, the 0.1 wt% PHI(Fe) photocatalyst has strong oxidative power due to its efficiency in H2O2 production, thus boosting the generation of nonselective hydroxyl radicals (●OH) via different pathways that can destroy HMF. We found that using 50 mM, the highest DFF production rate (393 μmol·h−1·g−1) was obtained in an aqueous medium under visible light radiation.

Objective: This study aimed to establish a new method for detecting furfurals in tea. Methods: A gas chromatography tandem mass spectrometry (GC-MS/MS) method was established for the simultaneous determination of furfural, 5-methylfurfural, 5-hydroxymethylfurfural and 2-Acetylfuran in tea. The sample pretreatment method and GC-MS/MS method were optimized. Furfural-D4 was used as the internal standard. The sample was extracted by acetonitrile, treated and purified by QuEChERS method, and determined by GC-MS/MS multi reaction monitoring (MRM). Results: The four furfurals showed good linear relationship in the mass concentration range of 1.25~200.00 μg/L, with the correlation coefficient ≥0.999 0, and the detection limit (S/N=3) was 1 μg/kg, with the recovery range of standard addition of 89.10%~113.02%. Most of the commercially available tea samples were found to contain furfural. Conclusion: This method in the present study is simple, rapid and can eliminate the interference of complex matrix in tea. The result is accurate, reliable and sensitive. It is suitable for the simultaneous determination of four furfurals in tea.

Maillard reaction (MR) is widely found in food heat processing, can not only give food color and flavor, but also produce harmful or odorous substances. 2,3-dihydro-3,5-dihydroxy-6-methyl-4(H)-pyran-4-one (DDMP), 5-hydroxymethylfurfural (HMF) and furfural are important products of MR. In this paper, three kinds of caramelization and three kinds of Maillard reaction models were established to study the formation of DDMP, HMF and furfural. Results indicated that HMF and furfural were easily generated in fructose and xylose caramelization models, respectively. In Maillard reaction model, the participation of lysine inhibited the production of HMF and furfural, and promoted the production of DDMP. Combined with the characterization of the intermediate product and the final product, the structural difference of monosaccharides was the main factor affecting the production of the three compounds. Lysine competitively inhibited the caramelization pathway of monosaccharide degradation, thereby inhibiting the production of HMF and furfural. The present paper would provide guidance on the production, control and oriented synthesis of DDMP, HMF and furfural in food thermal processing industry.

Electrocatalytic upgrading of 5-hydroxymethylfurfural (HMF) provides a promising way to obtain both high-value-added biomass-derived chemicals and clean energy. However, development of efficient electrocatalysts for oxidizing HMF with depressed side reactions remains a challenge. Herein, we report a nickel-phytic acid hybrid (Ni-PA) using natural phytic acid as building block for highly efficient electrocatalytic oxidation of HMF to 2, 5-furandicarboxylic acid (FDCA). Due to the coordination of nickel ion and phosphate groups of phytic acid molecule, high selectivity and yield of FDCA were achieved at 1.6 V vs. RHE. Besides, Ni-PA has a higher electrochemical surface area and lower charge-transfer resistance than Cu/Fe-PA, which significantly promotes the oxidation of HMF to FDCA. This work demonstrates the potential of metal-phytic acid hybrids as effective electrocatalysts for biomass valorization.

Camel milk has unique compositional, functional and therapeutic properties compared to cow's milk and also contains many protective proteins with anti-cancer, anti-diabetic and anti-bacterial properties. In this experiment, fresh camel milk was heat-treated at different temperatures and times, and the changes in Millard reaction products were analyzed. Meanwhile, headspace-gas chromatography-ion migration spectrometry (HS-GC-IMS), electronic nose and electronic tongue were used to analyze the changes of volatile components in camel milk after different heat treatments. The results showed that the Maillard reaction was more severe with the increase of heat treatment, and the contents of furosine and 5-hydroxymethylfurfural increased significantly when the heat treatment temperature was higher than 120°C. HS-GC-IMS results showed that the contents of aldehydes and ketones increased obviously with the increase of heat treatment degree. The study clarifies the effects of different heat treatment degrees on Maillard reaction degree and flavor of camel milk, which has practical production guidance significance for the research and industrialization of liquid camel milk products.

[Display omitted] Electrocatalytic oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA) was examined as an alternative to thermocatalytic methods in which two-dimensional (2D) cobalt-metal–organic framework (Co-MOF, ZIF-L-Co) nanoplate arrays were prepared on nickel foam (NF) and then transformed into hierarchical porous Co 3 O 4 nanostructures by chemical etching and low temperature annealing to form electrode materials. Hierarchical porous nanoarrays formed during synthesis enlarged the surface area of the as-prepared catalysts introduced a large number of defects and exposed active sites leading to reduced charge diffusion, improved mass transfer and efficient HMF oxidation. Co 3 O 4 /NF electrode materials were able to achieve a current density of 10 mA·cm−2 at an overpotential of 105 mV in 1 M KOH with 10 mM HMF, which was reduced by 175 mV compared with water oxidation. Electrocatalytic oxidation experiments afforded 100 % HMF conversion and 96.7 % FDCA yields with a minimum 96.5 % faradaic efficiency at 1.43 V vs RHE. The proposed MOF-structured synthesis method fundamentally reduces charge diffusion, improves mass transfer of electrodes and is generally applicable to fabrication of hierarchical porous nanostructured materials. [ABSTRACT FROM AUTHOR]

In this study, an efficient method for the separation of 5‐hydroxymethylfurfural by the specific adsorption of dimethyl sulfoxide (DMSO) with cellulose microgels fabricated by electron beam irradiation was developed. The cellulose microgel was recovered and reused although this was accompanied by a decrease in the separation efficiency. A series of characterizations, including ultraviolet and infrared spectroscopy, scanning electron microscopy, differential scanning calorimetry, thermogravimetric analysis, and swelling ability tests, were performed to determine the adsorption behavior of the chemical structures of the microgel toward DMSO. The results showed that after the first run, the chemical structure of the recovered microgel did not change significantly. Electron‐beam etching played a pivotal role in conferring a special capacity for enriching DMSO in its matrix on the microgel. [ABSTRACT FROM AUTHOR]

In recent years, active research has been carried out in the field of catalysts for the electrooxidation of water-soluble products of biomass processing on the anodes of electrolysers, coupled with the process of producing hydrogen at the cathodes of these devices. Biomass processing products that are promising for electrooxidation are glycerol, glucose, furfural and 5-hydroxymethylfurfural. The review examines studies of catalysts for the electrooxidation of glycerol, glucose, furfural, and 5-hydroxymethylfurfural based on metals of various groups. Electrooxidation of these organic compounds on catalysts based on noble metals (platinum group metals and gold) and their alloys begins in the potential range from 0.3 to 0.7 V [reversible hydrogen electrode (RHE)], reaching a maximum at ~1 V (RHE). The main disadvantage of catalysts based on noble metals is their high cost. Nickel and сobalt are considered promising among the non-noble metals studied as components of catalysts for these reactions. But in the presence of catalysts based on these metals, the electrooxidation reactions of the noted organic compounds begin at potentials above 1 V (RHE). Glyceraldehyde, dihydroxyacetone, glyceric, tartronic, glycolic, oxalic, glyoxalic and mesoxalic acids can be obtained from the electrooxidation of glycerol. Valuable products of the electrooxidation of glucose, furfural, and 5-hydroxymethylfurfural are gluconic, 2-furancarboxylic, and 2,5-furandicarboxylic acids, respectively. [ABSTRACT FROM AUTHOR]

Copyright of Chemistry & Industry of Forest Products is the property of Chemistry & Industry of Forest Products Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The conversion of macromolecular saccharides (fructose, glucose, sucrose, and inulin) to 5‐hydroxymethylfurfural (HMF) is often limited by the mass transfer resistance of existing catalysts. Herein, a two‐dimensional metal–organic framework (NUS‐8‐PhSO3H) containing high densities of dual acidic sites (Lewis and Brønsted acid sites) was developed for the first time by diazo grafting. Characterization results and reaction kinetics showed that the rapid molecular diffusion leads to an unusual pseudozeroth reaction order and a considerably lower apparent activation energy for the fructose reaction over NUS‐8‐PhSO3H in contrast to the first order and higher activation energy over three‐dimensional counterpart (NUS‐16‐PhSO3H) and reported catalysts. In addition, NUS‐8‐PhSO3H can also produce substantially high HMF yields and has a low activation energy for other saccharides (glucose, sucrose, and inulin) by powerful tandem steps, including polysaccharide hydrolysis, glucose isomerization, and fructose dehydration. The preparation of hydrophobic acidic NUS‐8‐PhSO3H provides an efficient means of synthesizing HMF from various saccharides. [ABSTRACT FROM AUTHOR]

The biomass‐derived platform compound 5‐hydroxymethylfurfural (HMF) has been hailed as the "Sleeping Giant" due to its promising applications, and it occupies a critical spot in the biomass upgrading roadmap. HMF is typically produced from cellulose and its monosaccharides via a complex tandem conversion with multiple steps (i. e. cellulose depolymerization, glucose isomerization, fructose dehydration, etc.). Previous investigations have confirmed the irreplaceable contribution of solvents in regulating the tandem conversion of cellulose and its monosaccharides to HMF. However, the potential effects of solvents in contributing to this multi‐step tandem process have not yet been clearly elucidated. In this context, this Review aims to provide in‐depth insights into the intrinsic interactions between solvent system and substrate conversion (cellulose and its monosaccharides conversion), reaction regulation (reaction activity and selectivity regulation), as well as product acquisition (humins formation inhibition and product purification). It attempts to elucidate specific solvent effects to promote a more efficient tandem conversion of cellulose and its monosaccharides towards HMF. The insights provided in this Review may contribute to a more sustainable HMF production from biomass feedstocks and a further development of greener solvent systems. [ABSTRACT FROM AUTHOR]

The metallic cobalt supported on nitrogen dopped carbon material was employed as an efficient catalyst in the oxidative esterification of 5-hydroxymethylfurfural (HMF) to furan-2,5-dimethylcarboxylate (FDMC). The carbonization temperature has a significant effect on the morphology and structure of Co/N-C samples. The Co/N-C calcined at 900 °C exhibits the best catalytic performance and a 73.8% FDMC yield at 91.7% HMF conversion is measured at 130 °C for 20 h with K 2 CO 3 under 1 MPa O 2. The catalytic activity of Co/N-C was benefited by the synergistic effect between the metallic cobalt and nitrogen-doped carbon material. The reaction mechanism of FDMC formation was proposed. [Display omitted] • The effect of carbonization temperature on metal-lignin coordination complexes has been investigated. • The Co species improved the activity of N-doped carbon catalyst in oxidative esterification of HMF to FDMC. • The synergistic effect between metallic Co and N-dopped carbon boost the reactivity of Co/N-C catalyst. [ABSTRACT FROM AUTHOR]

Molten salt hydrate (MSH) is a good solvent for cellulose dissolution and an effective catalyst for cellulose conversion. In this work, a series of MSH was evaluated in terms of cellulose dissolvability, regeneration performance, and catalytic activity in cellulose conversion into 5-hydroxymethylfurfural (HMF). ZnBr2·3H2O–LiCl·3H2O showed good performance on cellulose dissolution and conversion. The effects of ZnBr2·3H2O concentration, reaction temperature, and time on cellulose conversion into HMF in ZnBr2·3H2O–LiCl·3H2O were optimized, and 48.7% HMF yield was reached at 60 wt.% ZnBr2·3H2O. The species of ZnBr2·3H2O–LiCl·3H2O were analyzed, and the function of species concentration was correlated with the product yield from the conversion of fructose. It was found that Br− and H+ were the active species for fructose dehydration into HMF. ZnBr3− and H+ catalyzed the conversion of fructose into furfural, which competed with the production of HMF. The reaction mechanism was proposed to understand the cooperate of species in MSH for cellulose conversion. [ABSTRACT FROM AUTHOR]

Thermally processed food always contains various types of harmful substances. Control of their levels in food is important for human health. This work used the extracts from green tea dust, old green tea, yellow tea, white tea, oolong tea, and black tea to simultaneously mitigate diverse harmful substances in fried potato chips. The six tea extracts (30 g/L) all showed considerable inhibitory effects on the formation of 5-hydroxymethylfurfural (reduced by 19.8%–53.2%), glyoxal (26.9%–36.6%), and methylglyoxal (16.1%–75.1%). Green tea and black tea extracts exhibited better inhibitory abilities than the other three teas and were further investigated for other harmful compounds by various concentration treatments. Finally, pre-soaking of fresh potato slices in 50 g/L extracts of green tea dust displayed, overall, the most promising inhibitory capacity of HMF (decreased by 73.3%), glyoxal (20.3%), methylglyoxal (69.7%), acrylamide (21.8%), and fluorescent AGEs (42.9%) in fried potato chips, while it exhibited the least impact on the color and texture. The high level of catechins in green tea dust may contribute most to its outstanding inhibitory effect, whereas the distinguished inhibitory effect of black tea extract was speculated to be attributable to the high levels of theaflavins and amino acids in the fully fermented tea. This study indicated that green tea dust, a predominant waste of the tea industry, had great potential to be exploited to improve food quality and safety. [ABSTRACT FROM AUTHOR]

5‐Hydroxymethylfurfural (5‐HMF) represents a well‐known class of lignocellulosic biomass‐derived platform molecules. With the presence of many reactive functional groups in the structure, this versatile building block could be valorized into many value‐added products. Among well‐established catalytic transformations in biorefinery, the reductive amination is of particular interest to provide valuable N‐containing compounds. Specifically, the reductive amination of 5‐HMF with ammonia (NH3) and molecular hydrogen (H2) offers a straightforward and sustainable access to primary furanic amines [i. e. 5‐hydroxymethyl‐2‐furfuryl amine (HMFA) and 2,5‐bis(aminomethyl)furan (BAMF)], which display far‐reaching utilities in pharmaceutical, chemical, and polymer industries. In the presence of heterogeneous catalysts contanining monometals (Ni, Co, Ru, Pd, Pt, and Rh) or bimetals (Ni−Cu and Ni−Mn), this elegant pathway enables a high‐yielding and chemoselective production of HMFA/BAMF compared to other synthetic routes. This Review aims to present an up‐to‐date highlight on the supported metal‐catalyzed reductive amination of 5‐HMF with elaborate studies on the role of metal, solid support, and reaction parameters. Besides, the recyclability/adaptability of catalysts as well as the reaction mechanism are also provided to give valuable insights into this potential 5‐HMF valorization strategy. [ABSTRACT FROM AUTHOR]

[Display omitted] • Selective transformation of HMF to DFF and H 2 is appealing yet still challenging. • Pt/CdS was efficient for dehydrogenation of HMF to DFF under visible light. • Strong interaction between furan ring in HMF with Pt NPs promotes this reaction. The selective transformation of 5-hydroxymethylfurfural (HMF) to 2,5-diformylfuran (DFF) with coproduction of hydrogen under visible light is appealing yet still challenging. In this manuscript, Pt/CdS nanocomposites obtained via photoreduction of [PtCl 6 ]2- over CdS were found to be an efficient and chemoselective photocatalyst for dehydrogenation of HMF to produce DFF under visible light, with simultaneously generation of stoichiometric hydrogen. An optimum performance was observed over 1.0 wt% Pt/CdS nanocomposite, with a complete conversion of HMF to DFF and stoichiometric hydrogen generated in 14 h. By comparison with the performance over MoS 2 /CdS, it is revealed that the superior performance for photocatalytic dehydrogenation of HMF over Pt/CdS should be ascribed to the strong interaction between the furan ring in HMF with Pt nanoparticles (NPs), which enables the protons released from HMF to fast transfer to Pt NPs in close vicinity for further reduction to generate hydrogen. This study provides an efficient and green strategy for the simultaneous transformation of biomass-derived HMF to DFF and the production of clean energy hydrogen. This work also highlights the great potential of photocatalysis in biomass valorization. [ABSTRACT FROM AUTHOR]

Electrochemical induced CuOOH/NiOOH active species performs the desirable activity for HMF oxidation. Nearly 100% FE (FDCA) was achieved in the paired-electrocatalytic system. Therefore, this work provides a new perspective for in-depth dissection of the reconstructed species. [Display omitted] • In-situ electrochemical reconstitution was proposed for CuO/Ni-BTC MOF. • Catalytic sites for HMF oxidation were determined as CuOOH/NiOOH species. • Close 100 % HMF conversion and 91.0 % FE FDCA were obtained at 0.55 V vs Ag/AgCl. • Paired electrocatalytic system exhibits superior performance for HMF oxidation. The biomass-derived 5-hydroxymethylfurfural (HMF) oxidation holds great significance for the sustainable production of value-added chemicals. However, the construction of active species with efficient oxidative-activity of alcohol/aldehyde still faces a great challenge. In this work, the reconstruction of CuO/Ni MOF successfully implanted CuOOH/NiOOH and deeply clarified their catalytic mechanism for HMF oxidation. It is worth noting that CuOOH/NiOOH exhibited an excellent self-healing ability during HMF oxidation, further realizing the reproducibility and long-term stability of catalyst. Moreover, a two-chamber electrocatalytic system combining HMF oxidation with 4-nitrophenol hydrogenation was established based on the activated CuO/Ni MOF. As a result, the overall reaction achieved a current density of 47.6 mA/cm2 at 0.55 V vs Ag/AgCl (3.0 h), and the corresponding conversion rate and Faraday efficiency reached nearly 100 %. This study provides new insight into the electrocatalytic-reconstruction strategy to implant active species for alcohol/aldehyde oxidation. [ABSTRACT FROM AUTHOR]

Oxygen vacancies (Vo) present in CeO2 nanoparticles (NPs) can effectively boost their photocatalytic activity under ultraviolet (UV) light. To improve photocatalytic performance, Cr- and Fe-doped CeO2 NPs with increased Vo were prepared using a simple method of doping Cr and Fe ions into CeO2 NPs, which was confirmed by an in-depth analysis of the structural and electronic changes. Through photocatalytic degradation (PCD) experiments with 5-hydroxymethylfurfural (HMF), we found that the PCD rates of the two doped CeO2 NPs were faster than that of the CeO2 NPs. In addition, the conversion of HMF to 2,5-furandicarboxylic acid (FDCA) using the doped CeO2 NPs occurred only through the mechanism of the selective oxidation to 5-hydroxymethyl-2-furancarboxylic acid (HMFCA), exhibiting better efficiency than using CeO2 NPs. [ABSTRACT FROM AUTHOR]

Hydroxymethylfurfural esters (HMF-esters) have great potential for additive development; for this reason, the goal of this work was to study the optimization of the esterification conversion of HFM and lauric acid using two lipases: the Novozym 435® biocatalyst and immobilized lipase from Thermomyces lanuginosus (TL). For the optimization of conversion, a three-level three-factorial Box–Behnken experimental design was used. The models achieved a good fit (R2 over 90%) for reactions catalyzed with Novozym 435® and immobilized TL lipase. The best conversion, 78.4%, was achieved with immobilized TL lipase using 30 mM HMF, 16 U of biocatalytic activity, and 50 °C. The kinetic parameters without inhibition by the substrate were determined using the Michaelis–Menten mechanism, whereby V Max   for both biocatalysts reached the highest values at 50 °C, and the highest enzyme–substrate affinities (low K m ) were reached at temperatures of 30 °C and 40 °C. It can be concluded that immobilized TL lipase has the potential to catalyze this reaction since, under optimal reaction conditions, an 80.6% conversion (value predicted) could be achieved. [ABSTRACT FROM AUTHOR]

The Maillard reaction products (MRPs) 3-deoxyglucosone (3-DG) and 5-hydroxymethylfurfural (HMF), which are formed during the thermal processing and storage of food, come into contact with technologically used yeasts during the fermentation of beer and wine. In order for the yeast cells to work efficiently, handling of the stress-inducing carbonyl compounds is essential. In the present study, the utilization of 3-DG and HMF by 13 Saccharomyces yeast strains (7 brewer's yeast strains, 1 wine yeast strain, 6 yeast strains isolated from natural habitats) was investigated. All yeast strains studied were able to metabolize 3-DG and HMF. 3-DG is mainly reduced to 3-deoxyfructose (3-DF) and HMF is completely converted to 2,5-bishydroxymethylfuran (BHMF) and 5-formyl-2-furancarboxylic acid (FFCA). The ratio of conversion of HMF to BHMF and FFCA was found to be yeast strain-specific and no differences in the HMF stress tolerance of the yeast strains and species were observed. After incubation with 3-DG, varying amounts of intra- and extracellular 3-DF were found, pointing to a faster transport of 3-DG into the cells in the case of brewer's yeast strains. Furthermore, the brewer's yeast strains showed a significantly higher 3-DG stress resistance than the investigated yeast strains isolated from natural habitats. Thus, it can be shown for the first time that Saccharomyces yeast strains differ in their interaction of 3-DG induced carbonyl stress. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Dalian Polytechnic University is the property of Journal of Dalian Polytechnic University Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Baking goods are an essential part of the diet worldwide and are consumed daily, so they represent ideal foods for vehicle health- and unhealth-promoting substances. This work aimed to study the influence of sugars and baking conditions of cookies on the final levels of the main reported hazardous chemical compounds such as 5-hydroxymethylfurfural (HMF), 3-deoxyglucosone (3-DG), glyoxal (GO) and methylglyoxal (MGO). The replacement of sucrose with fructose or glucose in the cookies recipe deeply modifies the levels of α-dicarbonyl compounds (DCs), particularly 3-DG, independently of the baking temperature used. A longer baking time, even a few minutes, can drastically modify the HMF level in cookies and the use of fructose or glucose in the recipe seems to ensure the optimal conditions for generating this compound. The use of sucrose is required to keep levels of the hazardous compounds below a few mg/kg. Additionally, the ability to retain water, the titratable acidity and/or the pH of the final products were influenced by the used sugars with effects on the final levels of DCs and HMF. The highest Ea values determined for DCs and HMF formation in the cookies with sucrose suggest that this system requires very high temperatures to increase meaningful levels of these molecules, limiting their accumulation. [ABSTRACT FROM AUTHOR]

In this work, a series of (x)Hf-β zeolite catalysts were prepared by a simple wet impregnation method and used as bifunctional catalysts with Lewis and Brønsted acid sites for synthesizing 5-hydroxymethylfurfural (5-HMF) from cellulose in H 2 O (NaCl) -THF biphasic system. Characterization analysis of (x)Hf-β zeolite catalysts with ICP-OES, N 2 adsorption-desorption isotherm, XRD, FTIR, SEM, NH 3 -TPD and Py-FTIR indicated that the catalysts possessed favorable pore structure, appropriate acid strength and acidity. A superior 86.3 % cellulose conversion and 53.4 % 5-HMF yield could be obtained at 200 °C for 4 h by using (5 %)Hf-β zeolite as the catalyst. In addition, the catalytic system provided a favorable 5-HMF yield from other carbohydrates, including glucose (85.1 %), sucrose (80.6 %), starch (65.1 %), maltose (65.0 %), dextran (59.9 %), and Moso bamboo (21.9 %). Nevertheless, the recyclability of (5 %)Hf-β zeolite catalyst was unsatisfactory and the 5-HMF yield showed a downtrend from 53.4 % to 24.4 % after 5 cycles. The catalyst has promising potential for converting biomass materials into high-value platform compounds. [ABSTRACT FROM AUTHOR]

Well‐ordered cubic mesoporous silicas KIT‐6 functionalized with sulfonic acid moiety (−SO3H) (up to 30 mol% based on silica) are synthesized via co‐condensation of tetraethoxysilane (TEOS) and mercaptopropyltrimethoxysilane (MPTMS) under acidic conditions using Pluronic P123 as the structure directing agent and H2O2 as the oxidant. The materials are used as heterogeneous catalysts for the dehydration of fructose to 5‐hydroxymethylfurfural (HMF), and the HMF yield as high as 88 % is achieved at 135 °C within 40 min in the presence of dimethyl sulfoxide (DMSO) as solvent. The effects of various experimental parameters, such as reaction temperature, time, solvent, and the mass ratio of fructose to catalyst, on the HMF yield are also systematically investigated. The catalyst could be easily recovered from the reaction and reused, and 83 % HMF yield could be retained after used for three cycles, which demonstrated the remarkable stability of the catalyst. [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]

The depletion of fossil resources makes the transition towards renewable ones more urgent. For this purpose, the synthesis of strategic platform-chemicals, such as 5-hydroxymethylfurfural (HMF), represents a fundamental challenge for the development of a feasible bio-refinery. HMF perfectly deals with this necessity, because it can be obtained from the hexose fraction of biomass. Thanks to its high reactivity, it can be exploited for the synthesis of renewable monomers, solvents, and bio-fuels. Sustainable HMF synthesis requires the use of waste biomasses, rather than model compounds such as monosaccharides or polysaccharides, making its production more economically advantageous from an industrial perspective. However, the production of HMF from real feedstocks generally suffers from scarce selectivity, due to their complex chemical composition and HMF instability. On this basis, different strategies have been adopted to maximize the HMF yield. Under this perspective, the properties of the catalytic system, as well as the choice of a suitable solvent and the addition of an eventual pretreatment of the biomass, represent key aspects of the optimization of HMF synthesis. On this basis, the present review summarizes and critically discusses the most recent and attractive strategies for HMF production from real feedstocks, focusing on the smartest catalytic systems and the overall sustainability of the adopted reaction conditions. [ABSTRACT FROM AUTHOR]

Glucose conversion to 5-hydroxymethylfurfural (HMF) is important to the success of a biorefinery. Herein, metal–organic frameworks (MOFs) with the UiO-66 structure were synthesised with decanoic acid as the modulator and used as the catalyst to optimise HMF yield. PXRD, FTIR, and TGA/DSC techniques were applied to characterise the materials. The analysis results show that the materials assembled from the ligand 2-nitroterephthalic acid and hexameric Zr-oxo clusters contain decanoic acid chemically bound in the framework that influences porosity, Lewis acidity, and hydrophobicity. The materials exhibit excellent catalytic performance for HMF production from glucose in DMSO as solvent, attributed to their abundant defects and high hydrophobicity due to the addition of the decanoic acid modulator. Influences of catalyst dosages, reaction duration, and temperature were comprehensively investigated, leading to 98.1% conversion of glucose and 54.5% HMF yield under optimised reaction conditions. The catalytic conversion shows some deterioration after four cycles, yet the reaction selectivity displays no significant decline. [ABSTRACT FROM AUTHOR]

A series of hydroxyapatite (HAP) supports with different Ca/P ratios were synthesized to prepare the MnOx/HAP catalysts. A MnOx/HAP catalyst showed highly efficient conversion of 5-hydroxymethylfurfural (HMF) into 2, 5-diformylfuran (DFF) in toluene solvent under no-alkali condition. 86.4% conversion of HMF with 90.9% selectivity of DFF at 120 °C for 12 h under 1.0 MPa O2 over the MnOx/HAP-10.0-400 were obtained. The redox of Mn4+/Mn3+ improved the oxidation of 5-HMF to DFF by the lattice oxygen, and the lattice oxygen was replenished by adsorbing O2 molecules. The reusability tests were found the catalyst could be reused up to four cycles without notable loss of catalytic activity. The MnOx/HAP-10.0-400 was a stable and reusable material for further industrial exploration of DFF in an environmentally friendly way. [ABSTRACT FROM AUTHOR]

Accumulation of chicken manure with litter (sawdust or fragmented straw) that is produced in large quantities at poultry farms (in producing 1 kg of poultry, 1–3 kg of manure with litter is obtained) poses a serious problem for the environment. Poultry farms are among the largest consumers of electricity, which can be generated by combusting manure with litter, also jointly with coal, in bubbling or circulating fluidized bed furnaces. For making the combustion more efficient and environmentally friendly (reducing carbon oxide emissions) the manure wetness and the content of volatiles in it should be decreased, and its heating value should be increased. To this end, manure with litter can be subjected, prior to its combustion, to pretreatment using the hydrothermal carbonization or torrefaction method. The article presents a comparison of the results obtained from studies of methods for processing a mixture of chicken manure and sawdust into biofuel in superheated steam. Chicken manure and its mixture with sawdust in the ratios 1 : 1, 1 : 2, and 2 : 1 were subjected to thermochemical treatment. Hydrothermal carbonization was carried out in a batch laboratory autoclave at a temperature of 220°С for 1 and 4 h. Biomass torrefaction was carried out in a fluidized bed reactor with the bed formed by biochar particles that were preliminarily obtained in superheated steam at temperatures of 300 and 350°С. It has been found that by applying the hydrothermal carbonization method, the carbon content in manure with litter can be increased from 42 to 63%, and the higher heating value from 16.7 to 17.8 MJ/kg. In turn, by applying the method of fluidized bed torrefaction in superheated steam, these indicators can be increased to 75% and 18.8 MJ/kg, respectively. The hydrothermal carbonization and torrefaction processes require significant energy expenditures. For making both processes more economically efficient, the possibility of extracting, from the spent water (or condensate), 5-hydroxymethylfurfural, which is regarded as a key reagent, a so-called platform chemical, for producing various practically important substances, including polymers, pharmaceutical drugs, solvents, and fuels, is being researched. It has been determined that the content of 5-hydroxymethylfurfural in these aqueous media makes 0.02–0.80 g/dm3 and depends on the biomass thermochemical treatment method and temperature at which the process was performed. [ABSTRACT FROM AUTHOR]

A reduction reaction of 5-hydroxymethylfurfural to 2,5-dimethylfuran (2,5-DMF) has been previously performed in an organic solvent under high-temperature conditions. For the relaxation of such reaction conditions, conventional palladium on carbon (Pd/C) was combined with vesicles composed of phospholipids or surfactants. Pd/C combined with 1,2-dioleoyl-sn-glycero-3-phosphocholine indicated a yield (25%) at 60 °C compared with Pd/C (17%). Vesicles at the liquid crystalline phase were advantageous for the reduction reaction of HMF. The yield of 2,5-DMF catalyzed by Pd/C combined with the vesicles depended on the lipid composition of the vesicles. It was clarified that the yield of 2,5-DMF could be controlled by the hydration property of the vesicles. Compared with conventional 2,5-DMF synthesis in an organic solvent, the use of vesicles made it possible to reduce the burden of using organic solvents in high-temperature conditions, although limitedly. [ABSTRACT FROM AUTHOR]

In this study, dried kumquat slices by different drying methods were stored at room conditions for 4 months and the product quality and stability were investigated during storage. For this purpose, the kumquat slices were dried by four drying methods including hot air, vacuum, ultrasound assisted osmotic pre-drying with hot air, and microwave assisted hot air drying with pretreatment by water blanching and without pretreatment. The moisture content and water activity values of dried kumquat slices increased during storage, and the lowest increase was determined in samples dried by hot air drying method without pretreatment. In general, L*, b*, chroma, hue angle values decreased, while a* and TRD values increased in all dried samples at the end of the storage. HMF values were ranged from 0.39 to 46.79 mg/kg during storage. It was observed that the ascorbic acid content of dried samples lost 28.36-75.61% during storage period. As a result of the study, it has been determined that drying of kumquat slices by without pretreatment is more suitable in terms of the examined quality properties during storage for 4 months.

A new acid catalyst derived from renewable sources was developed using an ultrasound-assisted approach. This involved the formation of a metal-organic framework called MIL-88(Fe) in the presence of carboxymethylated-cellulose (CMC). Subsequently, the catalyst underwent a post-synthetic modification to introduce further acidic –SO 3 H groups into the structure of the CMC/MIL-88(Fe) composite. Various examinations were carried out that validated the successful creation of the CMC/MIL-88(Fe)-SO 3 H catalyst. The effectiveness of the catalyst was assessed in the process of solid acid catalysis, specifically in the dehydration of fructose to produce 5-hydroxymethylfurfural (HMF). Through the employment of Response Surface Method (RSM) optimization, it was determined that utilizing 34 wt% of the catalyst at a temperature of 90 °C for 30 min resulted in a remarkable 98 % HMF yield. The catalyst exhibited good reusability, as it retained its catalytic effectiveness throughout four consecutive cycles. Comparative catalytic investigations involving CMC and CMC/MIL-88(Fe) composite without sulfonation revealed the superior activity of CMC/MIL-88(Fe)-SO 3 H catalyst, emphasizing the collaborative effect of CMC, MIL-88(Fe), and the impact of post-functionalization with -SO 3 H on the performance of the catalyst. [Display omitted] • A novel acidic biocomposite of MIL-88(Fe) and CMC was synthesized and characterized. • Acidic feature of bio-composite was enhanced by post-functionalizing with sulfonic acid. • The catalytic bio-composite was utilized for promoting rapid dehydration of fructose to HMF. • According RSM results, reaction in the presence of 34 wt% catalyst at 90 °C for 30 min yielded 98 % HMF. • The catalyst was efficient and recyclable for four consecutive runs. [ABSTRACT FROM AUTHOR]

Perylene diimide/Carbon nitride (PDI/CN) is an excellent photocatalyst consisting of self-assembled PDI with a π-π stacking structure, and has wide applications. But the effect of PDI morphology over their photocatalytic performance has been scarcely investigated. Herein, we successfully synthesized three different morphologies of PDI, inducement formed by different organic solvents, and coupled them with CN, respectively. For simultaneous production of H 2 O 2 and DFF, their photocatalytic activity has the order of PDI-F/CN > PDI-S/CN > PDI-B/CN. H-stacked PDI-F/CN exhibits good crystallinity, larger specific surface area, higher π-conjugation and large dipole moment, which could improve charge-carrier separation, and its activity was 4.2-fold higher than that of CN. Theoretical calculation results indicated that the PDI-F/CN heterojunction could benefit the adsorption of O 2 and 5-HMF and lower the energy barrier, which is an important factor for the enhanced photocatalytic activity. This work provides a new and excellent photocatalyst for biomass oxidation. [Display omitted] • We successfully synthesized three different morphologies of PDI, inducement formed by different organic solvents. • Photocatalytic activity has the order of PDI-F/CN > PDI-S/CN > PDI-B/CN for simultaneous production of H 2 O 2 and DFF. • H-stacked PDI-F/CN exhibits larger specific surface area, higher π-conjugation and large dipole moment. • PDI-F/CN heterojunction could benefit the adsorption of O 2 and 5-HMF. [ABSTRACT FROM AUTHOR]

• Sugar-based polymers are a green substitute for existing petroleum-based polymers. • FDCA derived from sugar can be a monomer for polyethylene furandicarboxylate (PEF) • 5-HMF route is a promising for the production of FDCA. • Catalyst development and the process optimization are the main challenges. • Despite success in batch production of FDCA continuous processes are under research. Sugar platform biorefinery has shown promise for production of value-added chemicals such as 5-Hydroxymethylfurfural (5-HMF) and 2,5-furandicarboylic acid (FDCA). FDCA is a monomeric platform used in manufacturing of polymers such as polyethylene 2,5-furandicarboxylate (PEF), which is a green replacement for petroleum-based polyethylene terephthalate (PET). Various routes have been developed for FDCA synthesis, in which the 5-HMF route has shown a great potential for commercialization. In this 5-HMF route, 5-HMF that is generated by catalytic dehydration of carbohydrates, is further oxidized selectively to produce FDCA over either homogeneous or heterogeneous catalysts. Heterogeneous solid acid catalysts are more advantageous owing to ease of recovery and reuse. Different types of reactors, batch or continuous-flow were employed in the HMF oxidation to produce FDCA, while continuous-flow reactors show more promise with respect to future upscaling for industrial applications as well as their effectiveness (owing to enhanced mass transfer and increased product yield). Continuous conversion of 5-HMF to FDCA was mostly carried out in fixed bed reactors using heterogeneous catalysts. FDCA was also produced electrochemically where anode and cathode electrodes act as catalysts facilitating the oxidation process. As a new development, crude 5-HMF generated from the dehydration of glucose was used as a feed for the oxidation reactor without any separation/purification, enabling direct conversion of glucose to FDCA. In addition, this work also provides a brief review on the most recent patents related to developing new processes, catalysts, and reactors for FDCA production, etc. [ABSTRACT FROM AUTHOR]

• Microwave-assisted synthesis with DES solvents achieved a high yield of 5-HMF (73.4%) in a short time. • Continuous flow synthesis of 5-HMF provided a promising yield of 40.5% from glucose. • Molecular dynamic simulations were used to explain the underlying mechanisms of glucose conversion. The conversion of glucose into 5-hydroxymethylfurfural (5-HMF), a crucial precursor for bio-based polymers, is an important area of research considering its potential for renewable materials. Current approaches frequently pose efficiency and cost difficulties. Herein we devise an optimal, efficient, and cost-effective technique for converting D-(+)-glucose monohydrate to 5-HMF using tetrabutylammonium bromide (TBAB) and two innovative synthesis methods: microwave-assisted and continuous flow reactors. We used a TBAB-based deep eutectic solvent (DES) system that incorporated microwave irradiation and an isopropanol/water solvent matrix. Crucial variables such as reaction time, temperature, solvent ratio, reactant and catalyst concentration were optimized. Surpassing the existing literature, we obtained 5-HMF yield of 73.4 %, at 110 °C in 1 min. In addition, synthesis was also carried in an innovative continuous flow reactor system to compare with microwave synthesis, which gave a yield of 40.55 % at 170 °C with a residence time of 20 min under optimized conditions, demonstrating scalability. The extraction of 5-HMF from the reaction matrix was carried with ethyl acetate with an efficiency of 92 %. Molecular dynamics simulations were implemented to analyze the initial mechanism of conversion of D-glucose monohydrate. Simulations revealed that the solvent composition, specifically the presence of Br- and Cl– ions, significantly influences hydrogen bond formation and catalytic performance, enhancing the conversion efficiency. Our novel approaches, which use microwave-assisted and continuous flow reactors, greatly enhance 5-HMF yield and efficiency while minimizing reaction time and energy consumption. The continuous flow system is essential for scaling up production since it provides a sustainable and energy-efficient solution for industrial applications. [ABSTRACT FROM AUTHOR]

Synopsis. The use of sustainable and environmentally friendly microbial resources as sulfur sources to replace potentially harmful sulfur-containing reagents. [Display omitted] • The Ni 3 S 2 @NC/NF electrocatalyst is synthesized via in situ derivation of S. cerevisiae utilizing a gas-phase route. • The Ni 3 S 2 @NC/NF electrocatalyst achieves 100 % HMF conversion, 95.6 % FDCA selectivity and 88.9 % FE. • Pathway of HMF oxidation to FDCA is verified by HPLC results and DFT calculations. The design and development of an efficient catalyst for the electrocatalytic oxidation reaction of 5-hydroxymethylfurfural (HMF) require a novel, cost-effective, environmentally friendly, and safe preparation method. In this study, we synthesized nickel sulfide nanorods encapsulated by nitrogen-doped carbon on a nickel foam substrate (Ni 3 S 2 @NC/NF), derived in situ from Saccharomyces cerevisiae. The utilization of a gas-phase route facilitated the binding of C, N and S elements to the NF substrate. The resulting Ni 3 S 2 @NC/NF catalyst exhibited excellent electrocatalytic performance in the HMF oxidation reaction (HMFOR), achieving a complete conversion of HMF, a selectivity of 95.6 % for 2,5-furandicarboxylic acid, and a Faraday efficiency of 88.9 % at a potential of 1.45 V. Moreover, in situ electrochemical impedance spectroscopy revealed an enhanced charge transfer rate for the Ni 3 S 2 @NC/NF catalyst during the interfacial HMFOR. Additionally, the catalyst demonstrated outstanding stability after five cycles of electrolysis. Therefore, this work provides a valuable guide for using microorganisms as sources of C, N, and S in the targeted synthesis of metallic electrocatalysts. [ABSTRACT FROM AUTHOR]

[Display omitted] • MAX phase with single-atom cobalt layer was constructed via A-site alloying strategy. • The Co-Sn synergy facilitated the adsorption and electrocatalytic conversion of HMF. • The suppressive effect of HMF on electrode reconstruction and OER. MAX phases have attracted considerable interest due to their structural diversities and potential applications. More than 150 MAX phases have been synthesized, especially expanding the range of A-site atoms from traditional main group elements to subgroup elements with outer layer d electronic structure. However, the functional applications for MAX phases remain somewhat limited. The A-site elements in MAX phases can amplify their inherent properties, transforming primary structural materials into multifunctional materials. As highly catalytic elements, introducing cobalt into the A-site of MAX phases can reveal surprising catalytic activities. Hence, the MAX phase with single-atom-thick cobalt layers was synthesized via an A-site alloying strategy in this work. The obtained V 2 (Sn 2/3 Co 1/3)C MAX phase demonstrates efficient electrocatalysis in 5-hydroxymethylfurfural (HMF) oxidation reaction along with hydrogen evolution reaction (HER). In-situ electrochemical studies discover that HMF can prevent the self-reconstruction of MAX phase and oxygen evolution reaction (OER). The overall reaction reaches 94.4% yield to 2,5-furandicarboxylic acid (FDCA) at 1.60 V. Density functional theory calculations suggest that the Co-Sn bimetallic synergy in the A-site promotes the reaction. This groundbreaking investigation into using MAX phases for biomass upgrading highlights their potential in green chemistry and beyond. [ABSTRACT FROM AUTHOR]

[Display omitted] • The formic acid/ZnCl 2 DESs facilitates the dissolution of cellulose. • 63.9 % yield of 5-hydroxymethylfurfural was obatined from cellulose. • The pathways through the conversion process are clearly revealed. • DESs/DMSO system can converts various carbohydrates into 5-hydroxymethylfurfural. The production of 5-hydroxymethylfurfural (HMF) from cellulose reserves is gaining attention as a value-added platform chemical, while achieving the desired HMF yield remains a formidable challenge. The present study proposed a novel coupled dissolution-decrystallization-conversion strategy for the efficient production of cellulose into HMF in formic acid/ZnCl 2 deep eutectic solvents (DESs)/dimethyl sulfoxide (DMSO) using AlCl 3 as a catalyst. The catalytic strategy involves a simple pre-hydrolysis of microcrystalline cellulose (MCC) followed by subsequent catalytic conversion and achieved a desired HMF yield of 63.9 % in 30 min at 170 °C. The characterization of regenerated MCC demonstrated a significant enhancement in the reactivity of MCC, achieved through the synergistic disruption of intra- and inter-molecular hydrogen bonds by formic acid/ZnCl 2 DESs. The isomerization of depolymerized glucose units to fructose via 1,2-hydride transfer and proton transfer of the enediol intermediate was proposed based on analysis of the reaction intermediates. The DESs/DMSO system is capable of full component recovery, while maintaining 50.8 % HMF yield after undergoing three cycles. The reaction system is well-suited for hydrolyzing a range of carbohydrates and resulting in outstanding yields of HMF. This study offers novel insights for advancing sustainable utilization of biomass resources. [ABSTRACT FROM AUTHOR]

Direct production of 2,5-dimethylfuran (DMF) from fructose is crucial for developing biomass-derived fuels, yet it presents significant challenges due to the need for multifunctional active sites for dehydration and hydrodeoxygenation. Meanwhile, the disposal of wine lees, a major winemaking by-product, incurs substantial costs. Herein, a hybrid catalyst system of sulfonated wine lees carbon (WLC-SO 3 H) and PtFe/C was introduced, achieving a DMF yield of 66.4 % directly from fructose. WLC-SO 3 H, with enhanced Brønsted acidity, demonstrated high activity in dehydrating fructose to 5-hydroxymethylfurfural (HMF) with a 98.2 % yield. PtFe/C effectively catalyzed the hydrodeoxygenation of HMF to DMF, driven by the strong interaction between Pt and Fe species. This interaction was confirmed through in situ DRIFTS and theoretical calculations, highlighting the system's superior catalytic performance. [Display omitted] • A hybrid catalyst of sulfonated wine lees carbon and PtFe/C was developed. • The hybrid catalyst catalyzed fructose to a yield of 66.4 % 2,5-dimethylfuran. • Sulfonated wine lees carbon dehydrated fructose to 98.2 % 5-hydroxymethylfurfural. • Strong interaction in PtFe/C promoted hydrodeoxygenation of 5-hydroxymethylfurfural. • Utilized wine lees waste for sustainable waste valorization and biofuel production. [ABSTRACT FROM AUTHOR]

• 5-HMF production from chitosan catalysed by DES were explored. • High efficiency was obtained under the optimized conditions. • The interactions between the HBA and HBD of DES were confirmed. • The solid residuals were characterized to reveal the conversion mechanism. This study explores an efficient catalytic system for the conversion of chitosan into 5-hydroxymethylfurfural (5-HMF) under hydrothermal conditions. The catalysts used are deep eutectic solvents (DESs) comprising choline chloride (ChCl) as the hydrogen bond acceptor (HBA) and various organic acids as the hydrogen bond donor (HBD). Among the DESs tested, the ChCl: oxalic acid (OA) combination exhibits the highest catalytic activity, resulting in a yield of 27.5% 5-HMF employed the optimized conditions. To elucidate the interaction between ChCl and OA, various analytical techniques were employed, including quantum chemical calculations, nuclear magnetic resonance (NMR), and Fourier transform infrared spectroscopy (FTIR). These investigations confirmed the formation of strong hydrogen-bonds between ChCl and OA. Furthermore, the solid residues obtained during the conversion process were characterized using FTIR, X-ray diffraction (XRD), and scanning electron microscopy (SEM). These analyses provide insights into the chemical structures and morphologies of the residues, revealing the gradual conversion of chitosan, along with the formation of humin by-products. [ABSTRACT FROM AUTHOR]

Corn-based snacks are important contributors to acrylamide daily exposure in European countries. Therefore, snacks (industrially produced) representing different product groups (corn chips, corn flakes, corn flips, popcorn, corn nut, corn cracker and corn cracker-bread) marketed in Serbia have been analyzed for acrylamide and color. Considering the addition of honey in some foodstuffs, the content of 5-hydroxymethylfurfural (HMF) in corn snacks has been determined and correlated with acrylamide content. Considerable variation in content of acrylamide between single foodstuffs (different brands) within food categories was found, which also applies to levels in different corn-based snack categories. The acrylamide content ranged from 1.9 to 799 ng/g in corn cracker-bread sample and corn nut bulk sample, respectively. With a mean value of 397 ng/g, popcorn samples exhibited the highest acrylamide content. These investigations showed that the content of acrylamide in about 37 % of the examined products was above the benchmark levels for whole-grain cereal-based food products defined in Regulation of the European Commission 2017/2158/EC. The results also showed that the color was not an indicator of acrylamide present in corn-based snacks, as well as that the content of HMF in the products was not correlated with the content of acrylamide (r = 0.019). The HMF content was highest in corn-based products with added sugars, honey, malt and molasses, such as corn flakes. • Corn-based snacks are important contributors to acrylamide human daily exposure. • The acrylamide content ranged from 1.9 to 799 ng/g in corn-based snacks. • Popcorn samples exhibited the highest acrylamide content. • About 37 % of the examined products was above the benchmark levels of 300 ng/g. [ABSTRACT FROM AUTHOR]

[Display omitted] • Various feedstocks, catalysts, solvents and subsequent value-added routes for the production of HMF are summarized. • Factors affecting hydrothermal liquefaction are discussed. • The reaction mechanism of HMF synthesis and subsequent value addition of HMF is discussed in detail. • Research trends and problems faced in the future industrial production of HMF are proposed. 5-Hydroxymethylfurfural (HMF) is a high value-added biomass-derived chemical and one of the important biomass platform compounds. Currently, we mainly rely on the hydrolysis of saccharides to produce HMF. HMF has fewer applications on its own, but it can be transformed into other more useful compounds. Although a large number of papers have been published on the preparation and catalytic conversion of HMF, there are fewer comprehensive reviews of the whole process from the preparation of HMF based on biomass (reaction mechanism, influencing factors, catalysts, solvent systems) to the potential applications of HMF derivatives. Therefore, this paper reviews the recent advances in the preparation of HMF using saccharides as precursors by hydrothermal liquefaction, and systematically discusses the influencing factors affecting the yield of HMF under this technique, including the reaction temperature, pressure, the reaction residence time, the addition of additives, and the catalyst and solvent system of the reaction. In addition, we thoroughly discussed the value-added routes of HMF and their respective corresponding reaction mechanisms, and classified the value-added routes of HMF from the perspective of reaction mechanisms: hydrogenation, oxidation and hydrolysis. Finally, this paper summarizes the bottlenecks faced in terms of synthesis technology and value-added routes of HMF, and also looks forward to the future development direction of HMF. [ABSTRACT FROM AUTHOR]

Developing methods to transform industrial biomass waste into platform chemicals and materials is an important part of the EU circular bio-based economy. Thus, the present work focuses on the valorisation of crude sugarcane molasses (SCM) to 5-hydroxymethylfurfural (HMF) over starch-derived catalysts in water. A series of monofunctional catalysts having sulfonic, phosphate, or oxygen functionalities as Brönsted acid (BA) sites and a bifunctional catalyst containing phosphate groups as BA and SnO 2 as Lewis acid (LA) sites was prepared via one-pot hydrothermal carbonisation of starch. The effect of the varied active sites on these catalysts was tested in the cascade conversion of SCM to HMF in water using a microwave reactor. The results revealed that the maximum yield of HMF obtained from SCM depends solely on the chemistry of the catalyst's surface. It is independent of the catalyst's texture and is not proportional to the total acidity (A tot). A promising HMF yield of around 30 % was obtained from crude SCM in pure water over sulfonated hydrochar catalyst containing –SO 3 H, along with –OH and –COOH functionalities. The sulfonic groups were found to be the most selective towards fructose dehydration to HMF out of all of the BA sites tested here. On the other hand, introducing LA sites to the catalyst increased the conversion of glucose and selectivity to HMF compared to the monofunctional counterpart. However, the sugar conversion rate was lower over the bifunctional catalyst than that using sulfonated hydrochar. The catalytic system studied here was found to be suitable for high loadings of SCM. However, the best catalyst suffered a drop in activity after the first re-use. In general, obtaining high yields of HMF from SCM in water was hindered by a lack of effective isomerization of glucose to fructose and a high rate of side reactions producing humin, which were catalysed by impurities present in SCM. The transformation of SCM to HMF with sulfonated hydrochar occurred at a far slower rate than that of a solution of synthetic SCM (neat mixture of sugars) under similar conditions, which pointed to the negative effect of the impurities in the SCM matrix. Thus, it was shown that even though SCM is an interesting alternative feedstock for biorefineries, its purification prior to catalytic valorization might be necessary. • Sugarcane molasses is a suitable feedstock for HMF production in water. • Cheap mono and bifunctional sugar catalysts were prepared via the HTC. • 30 % HMF yield was obtained from molasses in water using sulfonated hydrochar. • Centrifuging of molasses removes metal impurities, increasing HMF yield. • The activity of Brönsted acid sites was in order sulfonic > oxygen > phosphorus. [ABSTRACT FROM AUTHOR]

The selective transformation of biomass-derived 5-hydroxymethylfurfural (5-HMF) into value-added chemicals is of significant interest to both academia and industry. In this study, we report on the direct hydrogenation of 5-HMF to 2,5-bis(hydroxymethyl)tetrahydrofuran (BHMTHF) instead of 2,5-dimethylfuran, achieving an impressive yield of 90.4% in 7 runs using a nickel phyllosilicate catalyst (Ni-PSL) under optimized conditions. The choice of solvent is crucial for minimizing side reactions, with tetrahydrofuran identified as an optimal solvent for reducing the formation of acetal by-products, which are typically promoted by protic organic solvents such as methanol or n -butanol. Pyridine–FTIR results reveal that the surface of Ni-PSL is enriched with Lewis acid sites, originating from coordinatively unsaturated Ni species, which are effectively generated through proper thermal treatment. Moreover, the total amount of acid sites in Ni-PSL can be modulated by adjusting the calcination temperature, without affecting the size of the Ni nanoparticles. These Lewis acid sites play pivotal roles in promoting the adsorption of the furan ring, thereby favoring the formation of BHMTHF under mild reaction conditions. However, an excess of Lewis acid sites promotes the cleavage of the C−OH bond, reducing the selectivity towards DMTHF. [Display omitted] • Ni-PSL is selected as ideal catalyst in 5-HMF hydrogenation yielding DHMTHF up to 90.4% in 7 runs. • The aprotic solvent like THF is beneficial to minimize by-products. • The surface acid of Ni-PSL can be regulated by thermal treatment. • Lewis acid sites enhance the adsorption of furan ring to produce DHMTHF as major product. [ABSTRACT FROM AUTHOR]

A novel bimetallic sulfide catalyst, Zn x Cd (1-x) S, synthesized via a one-step hydrothermal process, has demonstrated exceptional efficiency in the efficient oxidation of 5-hydroxymethylfurfural (HMF) to 2, 5-dimethylacylfuran (DFF). This transformation is achieved under environmentally benign conditions: without any external oxidant at room temperature and atmospheric pressure, with water as the solvent and visible light. The unique 3D flower-like nanosphere structure of Zn 0.4 Cd 0.6 S, characterized by a synergistic composition of ZnS and CdS, facilitates the simultaneous photocatalytic oxidation of water and HMF. The synergistic action of superoxide (∙O 2 -) and single-linear state oxygen (1O 2) served as the main active radicals generated in situ from water photolysis. Remarkably, Zn 0.4 Cd 0.6 S exhibited an excellent performance, achieving a remarkable product yield over 50 % and 75 % selectivity after only 3 h. This work presents a sustainable approach to the valorization of HMF and advances the field of photocatalysis without reliance on additional oxidants. • 3D flower-like Zn x Cd (1-x) S architecture catalysts were fabricated by one-step hydrothermal method. • Zn x Cd (1-x) S shows enhanced visible-light photocatalytic activity without any oxidant. • Zn x Cd (1-x) S can achieve high conversion and DFF yield at room temperature and atmospheric pressure. • The synergistic action of superoxide (•O 2 -) and single-linear state oxygen (1O 2) served as the main active radicals. [ABSTRACT FROM AUTHOR]

• Continuous production of HMF from fructose in μPBRs with solid acid catalyst. • Liquid-liquid two phase RTD in μPBRs is obtained. • It takes only 26.3 s to obtain 90.2 % HMF yield. • k L a is 1–3 orders of magnitude larger than conventional reactors. • The kinetic model is established and product yields are predicted. The efficient synthesis of the platform chemical 5-hydroxymethylfurfural (HMF) is of great significance for the production of downstream value-added bio-based chemicals. Herein, the highly-efficient and continuous synthesis of HMF is demonstrated in micropacked bed reactors (μPBRs) with HND-580. 95.3 % fructose conversion, 90.2 % HMF yield, and 99.3 % HMF extraction efficiency can be achieved within 26.3 s in μPBRs. The space–time yield (STY) of μPBRs is more than two times of magnitude greater than conventional fixed bed reactors (FBRs) and stirred tank reactors (STRs). The organic phase liquid holdup of liquid–liquid system is obtained at the range of 0.82–0.90, which is measured for the first time in μPBRs. The liquid–liquid mass transfer coefficient of μPBRs is 1.68 × 10-2 to 1.68 × 10-1 s−1, which is 1–3 orders of magnitude larger than STRs and packed columns. In addition, a heterogeneous kinetic model for the synthesis of HMF in water-MIBK biphasic system is established in μPBRs. The fructose conversion and HMF yield were predicted and the error was within ± 20 %. [ABSTRACT FROM AUTHOR]