Conversion Of Fructose Research Articles

Expanding the high-pH range of the sucrose synthase reaction by enzyme immobilization

The glycosylation of an alcohol group from a sugar nucleotide substrate involves proton release, so the reaction is favored thermodynamically at high pH. Here, we explored expansion of the alkaline pH range of sucrose synthase (SuSy; EC 2.4.1.13) to facilitate enzymatic glycosylation from uridine 5’-diphosphate (UDP)-glucose. The apparent equilibrium constant of the SuSy reaction (UDP-glucose + fructose ↔ sucrose + UDP) at 30 °C increases by ∼4 orders of magnitude as the pH is raised from 5.5 to 9.0. However, the SuSy in solution loses ≥80% of its maximum productivity at pH ∼7 when alkaline reaction conditions (pH 9.0) are used. We therefore immobilized the SuSy on nanocellulose-based biocomposite carriers (∼48 U/g carrier; ≥ 50% effectiveness) and reveal in the carrier-bound enzyme a substantial broadening of the pH-productivity profile to high pH, with up to 80% of maximum capacity retained at pH 9.5. Using reaction by the immobilized SuSy with automated pH control at pH ∼9.0, we demonstrate near-complete conversion (≥ 96%) of UDP-glucose and fructose (each 100mM) into sucrose, as expected from the equilibrium constant (Keq = ∼7 × 102) under these conditions. Collectively, our results support the idea of glycosyltransferase-catalyzed synthetic glycosylation from sugar nucleotide donor driven by high pH; and they showcase a marked adaptation to high pH of the operational activity of the soybean SuSy by immobilization.

Iron-Modified Acid Carbons for the Conversion of Fructose to 5-Hydroxymethylfurfural under Microwave Heating

Iron-Modified Acid Carbons for the Conversion of Fructose to 5-Hydroxymethylfurfural under Microwave Heating

Process Intensification and Reaction Kinetics for Synthesis of 5‐Hydroxymethyl Furfural Using DICAT‐1 Solid Acid Catalyst in a Batch Reactor

Abstract5‐HMF is a potential platform multifaceted molecule for various industrial applications and can be produced from biomass‐based hexose sugars. In the present study, the indigenously prepared catalyst DICAT‐1 (an acronym derived from DBT‐ICT Center for Energy Biosciences Catalyst #1) has been explored for fructose dehydration, using isopropyl alcohol (IPA) as a green and low boiling point (LBP) organic solvent. The exploration of heterogeneous DICAT‐1 adds specific advantages for 5‐HMF synthesis in terms of high yield, conversion, selectivity, catalyst separation, recycle, reuse, and so forth. Different variants of DICAT‐1, such as DICAT‐1A, DICAT‐1B, DICAT‐1C, and DICAT‐1D, having variable surface acidity were tested for fructose dehydration in the presence of IPA. Of the tested variants, DICAT‐1C provides good yield and selectivity of 5‐HMF. Thus, further process optimization study was conducted to obtain maximum yield, conversion, and selectivity using DICAT‐1C. The intensified process provides maximum 78% yield of 5‐HMF with 83% fructose conversion and 94% selectivity. The catalyst recyclability study showed the consistency in 5‐HMF yield, conversion, and selectivity for five consecutive recycle runs. The study of reaction kinetics showed the first‐order kinetics with an activation energy of 13.16 kJ/mole by using DICAT‐1C catalyst. Thus, the use of easily recyclable and robust catalyst provides an efficient route for production of 5‐HMF in presence of green solvent.

Acid and magnetic modifications of gum arabic as a dual approach for preparation of an efficient heterogeneous catalyst for conversion of fructose to value-added furanic compound

Acid and magnetic modifications of gum arabic as a dual approach for preparation of an efficient heterogeneous catalyst for conversion of fructose to value-added furanic compound

Green heterogeneous catalyst based on cross-linked carrageenans for direct conversion of fructose to ethyl levulinate

Ethyl levulinate (EL) is a biomass-derived compound, capable of being converted to an array of costly compounds and therefore is attracted by many researchers. In the present study, κ and ι-carrageenan grafted methylenebisacrylamide (MBA) catalysts (κC-g-MBA and ιC-g-MBA) were prepared and applied to convert fructose to EL. FT-IR spectroscopy, XRD of both low-angle and wide-angle, N2 adsorption-and-desorption, FESEM, and TGA were used to identify the catalysts. From the catalysts, κC-g-MBA and ιC-g-MBA revealed the desirable results for EL with 80 and 82 % yields, respectively. The various parameters like reaction temperature, time, catalyst quantity, and the original fructose quantity were studied. Furthermore, experimental design was employed to create the ideal conditions for the reaction temperature 180 °C for the reaction, 5 h for the duration of the reaction, and 50 mg of catalyst for EL chosen. In addition, the catalyst's capability for reuse was explored and the catalyst was used repeatedly without a significant change in the catalyst activity.

A sustainable one-pot synthesis of 2,5-diformylfuran from carbohydrates using tetracationic ionic liquid

A plausible solution to the current energy crisis is the development of cost-effective and inherently secure methods for accelerating the sustainable production of value-added compounds from biomass. In this study, we have developed a highly efficient catalytic system for the conversion of fructose into 2,5-diformylfuran (DFF) using tetracationic ionic liquids with dual Brønsted acid sites and four bromide ion sites. The presence of Brønsted acid sites promotes the production of 5-hydroxymethylfurfural (HMF), while the bromide anions react to form a DFF, which undergoes further transformation via the Kornblum mechanism. Under optimized conditions, a remarkable DFF yield of 99.6 % was attained in dimethyl sulfoxide (DMSO) at 140 °C for 6 h. Moreover, the catalyst exhibited excellent stability and reusability, indicating its potential for industrial application in the synthesis of DFF from fructose. With the help of this effort, Br- anion may be able to throw some light on the oxidation of HMF to DFF. Overall, this study highlights the promising application of tetracationic ionic liquid catalyst systems, showcasing the potential for the efficient utilization of renewable biomass resources and the synthesis of high-value-added compounds.

Halloysite functionalized with dendritic moiety containing vitamin B1 hydrochloride as a bio-based catalyst for the synthesis of 5-hydroxymthylfurfural

Using halloysite clay and vitamin B1 hydrochloride, a novel acidic halloysite-dendrimer catalytic composite has been developed for conversion of fructose to 5-hydroxymthylfurfural. To grow the dendritic moiety on halloysite, it was first functionalized and then reacted with melamine, epichlorohydrin and vitamin B1 hydrochloride respectively. Then, the resulting composite was treated with ZnCl2 to furnish Lewis acid sites. Use of vitamin B1 as the cationic moiety of ionic liquid obviated use of toxic chemicals and resulted in more environmentally friendly composite. Similarly, dendritic moiety of generation 2 was also grafted on halloysite and the activity of both catalysts for conversion of fructose to 5-hydroxymthylfurfural was investigated to disclose the role of dendrimer generation. For the best catalytic composite, the reaction variables were optimized via RSM and it was revealed that use of 0.035 g catalyst per 0.1 g fructose at 95 °C furnished HMF in 96% yield in 105 min. Turnover numbers (TONs) and frequencies (TOFs) were estimated to be 10,130 and 5788 h−1, respectively. Kinetic studies also underlined that Ea was 22.85 kJ/mol. The thermodynamic parameters of ΔH≠\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\Delta {\ ext{H}}^{ \ e }$$\\end{document}, ΔS≠\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\Delta {\ ext{S}}^{ \ e }$$\\end{document} and ΔG≠\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\Delta {\ ext{G}}^{ \ e }$$\\end{document}, were calculated to be 23 kJ/mol, − 129.2 J/mol and 72.14 kJ/mol, respectively. Notably, the catalyst exhibited good recyclability and hot filtration approved heterogeneous nature of catalysis.

Highly-efficient synthesis of 5-Hydroxymethylfurfural from fructose in micropacked bed Reactors: Multiphase Transport, reaction Optimization, and heterogeneous kinetic study

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 %.

New halloysite-supported bio-based acidic ionic liquid as an efficient catalyst for conversion of fructose to 5-hydroxymethylfurfural: A combined experimental and computational studies

In an effort to design a bio-based catalyst with enough acidic strength to promote the conversion of fructose to 5-hydroxymethylfurfural, a series of halloysite clay-supported acidic ionic liquids were considered as potential candidates. The catalysts could be synthesized from reaction of Cl-functionalized halloysite with histidine, histamine, adenine and tryptophan, followed by treatment with chlorosulfuric acid. Predictive computational studies were performed and approved the superior activity of the histidine-based catalyst. In addition, the computational studies aimed to identify the optimal catalyst using Density Functional Theory (DFT) calculations and other characterization techniques, particularly non covalent interactions plots. Aknowledged by computational results, histidine based catalyst was prepared, characterized and its catalytic activity and recyclability were appraised for the synthesis of 5-hydroxymethylfurfural from fructose as a bio-based starting material. The reaction conditions were optimized and it was revealed that using 30 wt% catalyst, the desired product could be achieved at 100 °C within 1 h. Notably, the catalyst exhibited high recyclability and efficiently promoted the reaction of other mono-saccharides as well.

Tandem catalytic conversion of glucose and cellobiose to 5-ethoxymethylfurfural with record yields

The conversion of biomass-derived carbohydrates to 5-ethoxymethylfurfural (EMF) is a fascinating reaction with 100% carbon atom utilization. Although effective conversion of 5-hydroxymethylfurfural (HMF) and fructose to EMF have been achieved, the direct conversion of glucose only gave low EMF yields. Herein, we reveal that the combinations of common Lewis acid with Brønsted acid in ethanol universally catalyze rapid etherification of glucose to intractable ethyl glucoside (EGL), as impedes the further conversion toward the desired products. The synergy of large-pore tin phosphate (SnPO) bearing strong Lewis acidic sites with acidic ionic liquid 1-(4-sulfobutyl)-3-methylimidazolium chloride (BSO3HMIMCl) enable tandem catalytic conversion of glucose, cellobiose and starch to EMF with record yields (61.7%, 61.8% and 55.7%, respectively), far exceeding previous reports. This transformation probably occurs via multiple parallel pathways, where water molecules generated by dehydration cooperate with acid and Cl- to hydrolyze EGL back to glucose, thus forming a positive feedback on EMF production.

Sulfonated graphitic carbon catalyst derived from coffee waste: A sustainable valorization approach for highly efficient production of 5-hydroxymethylfurfural (5-HMF) from fructose

According to recent research, a sulfonated 2D graphitic carbon catalyst for the dehydration of fructose to the platform chemical 5-Hydroxymethylfurfural (5-HMF) can be made from used ground coffee. By carbonizing and activating at different temperatures, sulfonated graphitic carbon (SC) catalysts with varied chemical compositions and textural characteristics were obtained. The physical and chemical characteristics of the SC catalysts were assessed using XRD, Raman, SEM-EDX, HR-TEM, BET analysis, and XPS. Due to its microporous structure, SC-900 exhibited a high specific area and demonstrated selective and efficient production of 5-HMF from fructose. All in all, the surface acidity of catalysts was measured by NH3-TPD, and acid-base titration methods. The SC-900 catalyst, designed through carbonization at 900 ℃, achieved a fructose conversion rate of 100 % and a 5-HMF yield of 97.91 % without generating any by-products. This indicates the catalyst essentially produces 5-HMF under the specified optimal conditions (140 ℃, 90 min) observed in this study. To determine the origins of the highly efficient and highly selective conversion of fructose to 5-HMF, the performance of the SC catalysts was systematically investigated vi-a-vis their physical and chemical properties. The development of microporous SC catalysts and their application as catalysts not only enhances the value of waste coffee but also provides an environmentally friendly approach for converting carbohydrates into 5-HMF.

Intensification of fructose dehydration into 5‐HMF and subsequent oxidation to 2,5‐FDCA using ultrasound

AbstractUltrasound‐assisted dehydration of fructose into 5‐hydroxymethylfurfural (5‐HMF) and subsequent oxidation to furandicarboxylic acid (2, 5‐FDCA) is studied in the current work with the main objective being to elucidate the effectiveness of ultrasound for intensified synthesis. The effect of reaction parameters like ultrasound power, duty cycle, reaction time, reaction temperature, solid to solvent ratio, and fructose concentration on the dehydration of fructose into 5‐HMF has been studied. Optimized conditions established were ultrasonic power of 140 W, duty cycle of 60%, reaction time of 60 min, temperature of 100°C, and fructose:dimethylsulfoxide (DMSO) ratio of 3:100 (g/mL), which resulted in the highest 5‐HMF yield of 96% and fructose conversion of 100%. The conventional method carried out at optimized conditions resulted in only 13.5% as 5‐HMF yield. The obtained 5‐HMF was further oxidized to FDCA using Pd/C as the catalyst, H2O/DMSO as solvent, and K2CO3 as a base also using ultrasonic irradiation at 140 W power and 22 kHz frequency in the presence and absence of O2 as oxidant. 100% conversion of 5‐ HMF was obtained in 30 min and 4 h using ultrasound in the presence of O2 and in absence of O2, respectively. 75% conversion of 5‐HMF was observed using the conventional method in 5 h in the presence of O2. Overall, the intensification benefits of using ultrasound at both steps of synthesis has been successfully elucidated.

Boosting catalytic performance of Amberlyst‐15 by modulating surface properties for synthesis of 5-hydroxymethylfurfural from high-concentration fructose

The large-scale production of 5-hydroxymethylfurfural (HMF), a “sleeping giant” in sustainable chemistry, is frequently hampered by the severe formation of humins during the acid-catalyzed dehydration of high-concentration fructose. In this work, we demonstrate that the HMF yield could be remarkably enhanced by boosting the catalytic performance of a commercially used Amberlyst-15 solid acid organocatalyst, wherein the formation of humins could be effectively inhibited. We show that the modification of Amberlyst-15 with a typical cationic surfactant (i.e., cetyltrimethylammonium bromide (CTAB)) via charge interaction between sulfonic acid groups and quaternary ammonium cations led to an improved surface hydrophobicity and a reduced Brønsted acid density on the modified catalyst, thereby contributing to a complete suppression of HMF rehydration and remarkable suppression of humin formation via paths of both etherification-dehydration-condensation and degradative-condensation of fructose and/or HMF. As a result, the catalytic conversion of fructose over the CTAB-modified Amberlyst-15 catalyst in a low-boiling mixed solvent composed of 1,4-dioxane and H2O at 140 °C within 2 h led to high HMF yields in range of 53.3 ∼ 63.1 mol% in converting high-concentration fructose (10.0 ∼ 50.0 wt%), wherein an average enhancement of 20 mol% in product yield was achieved when compared with that over un-modified Amberlyst-15. Moreover, the adsorption of humins on solid catalyst was significantly reduced due to the enhanced surface hydrophobicity and alleviated formation of humins, which accounted for a stable catalytic performance of the modified Amberlyst-15 catalyst for at least five runs. This work highlights the rational adjustment of the surface wettability of a commercial solid acid catalyst to suppress the undesired humin formation for future HMF biorefinery.

Conversion of sugars into methyl lactate over poly (ionic liquid)s functionalized Sn/beta zeolites

Methyl lactate (MLA) is a versatile high value platform chemical prepared from biomass carbohydrates, with widely application in the pharmaceutical, food, pesticide, and cosmetics. The current study presented a one-pot catalytic conversion of sugars to MLA over poly (ionic liquid)s functionalized Sn/Beta zeolites under mild conditions. The Sn/Beta zeolites were prepared by an impregnation method, followed by modification with poly (vinyl imidazole) ([PVIM]) via an in-situ free radical polymerization method. Dosages of polymer and Sn, calcination temperature, reaction temperature, catalyst amount, substrate concentration, and reaction times were optimized. Results showed that an MLA yield of 61.4 % was obtained over 3[PVIM]-Sn/Beta with complete conversion of fructose at 140 °C for 8 h. The physicochemical properties were characterized by XRD, BET, FTIR, CO-DRIFTS, NH3-TPD and pyridine-FTIR analysis, indicating the coexistence of Lewis and Brønsted acid sites. Finally, a possible reaction mechanism was proposed that the weak Lewis acidity of imidazole rings of [PVIM] effectively regulated the local microenvironment of active sites, thus promoting the interaction of the active sites with electronegative oxygens of sugars. This study can provide as a reference for the development of solid acid catalysts for the catalytic conversion of biomass to platform chemicals.

Highly efficient and recyclable chromium/nitrogen-doped carbon nanotube catalysts with unexpected active sites for conversion of fructose into 5-hydroxymethylfurfural

5-Hydroxymethylfurfural (HMF) has great promise as a versatile platform chemical for the synthesis of a wide range of other chemical compounds. The preparation of HMF from carbohydrates for industrial applications, especially fuels and fine chemicals, has received much more attention. In the present study, metal/nitrogen-doped carbon nanotubes (M/N-CNTs) were produced using a one-step carbonization method and used as an exceptional catalyst for converting fructose to HMF. The catalyst structure was determined using Energy-dispersive X-ray Spectroscopy (EDX), X-ray Diffraction (XRD), Scanning Electron Microscope (SEM), High-resolution X-ray Photoelectron Spectrometer (HRXPS), Transmission Electron Microscopy (TEM), Brunauer-Emmett-Teller (BET), and Fourier-transform Infrared Spectroscopy (FT-IR) techniques. The effects of temperature, catalytic loading, substrate feed concentrations, solvents, reusability, and scalability were carried out. This work achieved an excellent yield of HMF (91 % ± 2) utilizing Cr/N-CNTs as a catalyst for producing HMF at 120 °C for 180 min. Furthermore, the Cr/N-CNTs could be recovered and reused in industrial applications without significant loss of the catalytic activity.

High-efficient microwave-assisted conversion of fructose to 5-hydroxymethylfurfural over rice straw-derived sulfonated porous carbonaceous catalyst

5-Hydroxymethylfurfural (HMF) has emerged as a pivotal platform chemical derived from biomass, attracting considerable attention for its renewable applications. In this study, sulfonated rice straw biochar (RSBC-SA) catalysts were developed and employed for microwave-assisted catalytic conversion of fructose to HMF. The RSBC-SA catalysts, synthesized by pyrolyzing rice straw biomass at different temperatures and subsequent functionalization with sulfonic acid groups, were characterized using X-ray photoelectron spectroscopy (XPS), elemental analysis, temperature programmed desorption (TPD) and Fourier-transform infrared spectroscopy (FT-IR). A comparative analysis of catalytic performance between microwave irradiation and conventional oil bath heating revealed a substantial enhancement in efficiency with the former. Notably, the 700 ℃ pyrolyzed RSBC-SA catalyst demonstrated the highest HMF yield of 92.6 % within just 5 min of reaction time under a microwavehydrothermal condition, surpassing the conventional oil bath heating method. In addition, moderate to high yields of HMF were achieved from different carbohydrates in our developed microwave reaction system, demonstrating significant catalytic activity. This superior catalytic effect under microwave irradiation can be attributed to the responsive dipole polarization of sulfonic acid groups, selective heating of the RSBC carrier via microwave absorption, and synergistic interactions among these factors. Overall, this study highlights the innovative use of agricultural waste and introduces a new method for creating microwave-responsive catalysts with biochar. This strategy enables efficient fructose conversion to HMF, promotes sustainable biomass transformation, and offers value-added uses for agricultural residues in chemical production.

Short-term adaptation as a tool to improve bioethanol production using grass press-juice as fermentation medium

Grass raw materials collected from grasslands cover more than 30% of Europe’s agricultural area. They are considered very attractive for the production of different biochemicals and biofuels due to their high availability and renewability. In this study, a perennial ryegrass (Lolium perenne) was exploited for second-generation bioethanol production. Grass press–cake and grass press-juice were separated using mechanical pretreatment, and the obtained juice was used as a fermentation medium. In this work, Saccharomyces cerevisiae was utilized for bioethanol production using the grass press-juice as the sole fermentation medium. The yeast was able to release about 11 g/L of ethanol in 72 h, with a total production yield of 0.38 ± 0.2 gEthanol/gsugars. It was assessed to improve the fermentation ability of Saccharomyces cerevisiae by using the short-term adaptation. For this purpose, the yeast was initially propagated in increasing the concentration of press-juice. Then, the yeast cells were re-cultivated in 100%(v/v) fresh juice to verify if it had improved the fermentation efficiency. The fructose conversion increased from 79 to 90%, and the ethanol titers reached 18 g/L resulting in a final yield of 0.50 ± 0.06 gEthanol/gsugars with a volumetric productivity of 0.44 ± 0.00 g/Lh. The overall results proved that short-term adaptation was successfully used to improve bioethanol production with S. cerevisiae using grass press-juice as fermentation medium.Key points• Mechanical pretreatment of grass raw materials• Production of bioethanol using grass press-juice as fermentation medium• Short-term adaptation as a tool to improve the bioethanol production

Fabrication of Keggin heteropolyacid modified macroporous covalent triazine frameworks with cyano group-rich defects for high-value utilization of carbohydrates

Designing an efficient, stable and recyclable solid acid for catalytic conversion of biomass and its derived compounds to synthesize high value-added organic chemicals could effectively alleviate the environmental problems caused by the energy crisis and carbon dioxide emissions. We prepared a Keggin heteropolyacid modified macroporous covalent triazine frameworks (PW12-MCTF) catalyst using a simple template method and post-impregnation technology for efficient conversion of carbohydrates to produce 5-hydroxymethylfurfural (HMF). Abundant structural defects of MCTF can be constructed in situ through incomplete polymerization, which can firmly bind H3PW12O40 through physical confinement effect and bonding interactions. Under optimized conditions, PW12-MCTF exhibited high HMF yield (79.4 % or 44.4 %) and the highest turnover frequency (4.39 min−1 or 1.86 min−1) in microwave-assisted catalytic conversion of fructose or inulin, respectively. Its catalytic activity surpassed that of bulk PW12-CTF and commercial acid zeolite and resin catalysts, due to its appropriate acid properties, well-dispersed nature in DMSO, inter-connected pore structure and outstanding nucleophilic effect of N-rich units. Density Functional Theory (DFT) study provides a plausible mechanism in PW12-CTF-catalyzed fructose dehydration. The catalytic performance of PW12-MCTF remained unchanged after three cycles due to strong bonding interaction between the Keggin units and framework of MCTF. This study will provide a new strategy for the fabrication of heteropolyacid modified covalent organic frameworks with structural defects to achieve the high-value utilization of carbohydrates.

Agro-waste derived sulfonated biochar material as a sustainable heterogeneous catalyst for conversion of fructose to 5-hydroxymethylfurfural

BackgroundDevelopment of biomass derived solid acid catalysts has the advantage to conform the green chemistry protocol for production of 5-hydroxymethylfurfural (HMF) by dehydration of fructose. MethodWe have reported waste cashew nut shell produced char as a biochar to prepare sulfonated biochar (SBC) catalyst by incorporating –SO3H group through treatment of concentrated sulfuric acid. Significant findingsDifferent methods of characterization including XRD, FT-IR, XPS, FESEM-EDS, TEM, TPD and BET analysis, were used to study the structure, morphology, chemical compositions, acidity and porosity of the produced SBC catalysts. The mesoporous nature of the material was confirmed by the powder X-ray diffraction patterns (PXRD), type IV isotherm (BET), and flakes-like structure was observed in TEM analysis. The catalyst showed high yield of HMF (92%) under optimum conditions of 120 °C in 60 min under biphasic solvent mixture of water and toluene (1:2). High yield could be explained by high acid strength of catalyst as observed by NH3-TPD analysis. Leaching test by Sheldon's method and recyclability experiment proved the need and heterogeneity of the present catalyst.

A binary catalytic system of sulfonated metal–organic frameworks and deep eutectic solvents towards highly efficient synthesis of 5-hydroxymethylfurfural from fructose

The green synthesis of 5-hydroxymethylfurfural (HMF) from biomass feedstocks is a crucial step for the development of sustainable fuels, resins and plastics. Here, a novel binary catalytic system was developed with metal–organic frameworks (MOFs) and deep eutectic solvents (DESs), which synergically exhibited a superior fructose dehydration efficiency with a HMF yield of 98.5% within 40 min. The replacement from terephthalic acid to 2,5-furandicarboxylic acid as the organic ligand in MOFs catalysts altered the coordination microenvironment of metal nodes, resulting in remarkably enhanced fructose conversion rates. The formation of hierarchical porous structures and moderated Brønsted acid sites in sulfonated MOFs further promoted the HMF production. Notably, HMF could be readily separated from the MOFs-DESs system and the MOF catalyst maintained stable performance after six recycles. Theoretical calculations clarified a positive correlation between the hydrogen bond interaction (between fructose and DESs components) energy and reaction efficiency. This study provided a new strategy to couple hierarchical solid acid catalysts with functional solvents binary towards effective and sustainable upgrading of biomass-derived molecules.