Dehydration Of Fructose Research Articles

Investigation on the preparation of 5-Hydroxymethylfurfural through fructose dehydration using in-line FTIR and in-situ 13C NMR

The formation mechanism and pathway of HMF from fructose dehydration were investigated using in-line FTIR monitoring and in-situ 13C NMR in this study. The results of the infrared absorption spectrum obtained at different time intervals during the reaction process showed significant inconsistencies with the acyclic pathway. However, the in-situ NMR analysis revealed the direct observation of two intermediates, fructose furan and (4R-5R)-4-hydroxy-5-hydroxymethyl-4,5-dihydrofuran-2-formaldehyde, providing direct evidence to support the cyclic carbocation pathway. This study also included theoretical analysis of the intermediates involved in the key steps of various reaction pathways using density functional theory (DFT) calculations. The key steps in the cyclic pathway were found to have lower activation energy compared to the acyclic pathway, while exhibiting significant differences in electronegativity at the reaction sites. The computational results not only reveal but also provide support for the rationality of the cyclic formation mechanism. The response surface methodology (RSM) was utilized to optimize the preparation process of HMF through fructose dehydration. It enabled determination of the significance order for each factor (reaction temperature > reaction time > mass percentage of water in the solvent) and identification of the optimal process conditions (reaction time of 3.5 h, reaction temperature of 143.5 °C, mass percentage of water in the solvent of 5.0 %, and maximum yield of 5-HMF reaching 82.4 %).

Sulfonic acid-functionalized chitosan–metal–organic framework composite for efficient and rapid conversion of fructose to 5-hydroxymethylfurfural

In pursuit of designing a bio-based catalyst for the dehydration of biomass (i.e., fructose) to 5-hydroxymethylfurfural, a novel catalytic composite was prepared by in-situ formation of an Al-based metal–organic framework in the presence of chitosan. To enhance the acidity of the as-prepared catalyst, it was sulfonated with chlorosulfonic acid. Various characterization techniques, including XRD, XPS, FTIR, SEM/EDX, TGA, and elemental mapping analysis were applied to validate the formation of the acidic composite. Fructose dehydration conditions were also optimized using Response Surface Method (RSM) and it was found that reaction in the presence of catalyst (23 wt%) in DMSO, at 110 °C for 40 min led to the formation of HMF in 97.1%. Noteworthy, the catalyst was recyclable and stable up to five runs with a minor reduction in its activity.

Phosphazene-Based Covalent Organic Framework as an Efficient Catalyst (COF-1) for the Dehydration of Fructose to 5-HMF.

5-Hydroxymethylfurfural (HMF) is a promising organic platform for producing value-added chemicals. In this work, we focused on using a covalent organic framework (COF-1) as a heterogeneous catalyst for the dehydration of fructose to 5-HMF. The unique phosphazene unit-functionalized pores of COF-1 are essential active sites for catalytic performance. The results show that under the optimized reaction conditions, a maximum yield of 90% was obtained within 1.5 h at 120 °C. Furthermore, the effects of the catalyst load, reaction temperature, and usage of solvents for the improvement of reaction yield were investigated. The catalyst recyclability results showed that the yield of HMF did not change appreciably (90-82%) over five consecutive recycling runs. This work provides a viable strategy by applying phosphazene-based COF-1 for the efficient synthesis of HMF from renewable biomass. The synthesized HMF was further used for the synthesis of the biopolymer monomer furan-2,5-dimethylcarboxylate (FDMC) through N-heterocyclic carbene (NHC)-catalyzed oxidative esterification.

A Network of Processes for Biorefining Burdock Seeds and Roots.

In this work, a novel sustainable approach was proposed for the integral valorisation of Arctium lappa (burdock) seeds and roots. Firstly, a preliminary recovery of bioactive compounds, including unsaturated fatty acids, was performed. Then, simple sugars (i.e., fructose and sucrose) and phenolic compounds were extracted by using compressed fluids (supercritical CO2 and propane). Consequently, a complete characterisation of raw biomass and extraction residues was carried out to determine the starting chemical composition in terms of residual lipids, proteins, hemicellulose, cellulose, lignin, and ash content. Subsequently, three alternative ways to utilise extraction residues were proposed and successfully tested: (i) enzymatic hydrolysis operated by Cellulases (Thricoderma resei) of raw and residual biomass to glucose, (ii) direct ethanolysis to produce ethyl levulinate; and (iii) pyrolysis to obtain biochar to be used as supports for the synthesis of sulfonated magnetic iron-carbon catalysts (Fe-SMCC) to be applied in the dehydration of fructose for the synthesis of 5-hydroxymethylfurfural (5-HMF). The development of these advanced approaches enabled the full utilisation of this resource through the production of fine chemicals and value-added compounds in line with the principles of the circular economy.

Synthesis/separation of 5-hydroxymethylfurfural converted from fructose promoted by H2O–CO2 biphasic system with solid catalysts: Experimental and kinetic modeling approaches

5-Hydroxymethylfurfural (5-HMF) is an industrially valuable compound typically produced by dehydration of fructose converted from cellulosic biomass. However, the formation of 5-HMF is accompanied by its conversion into by-products, such as levulinic and formic acids, decreasing its yield. Therefore, biphasic processes are attracting much attention allowing the efficient simultaneous synthesis and separation of 5-HMF. In this study, a biphasic system using water with high-pressure carbon dioxide, the most environmentally friendly solvents, combining with a solid catalyst is used to achieve 5-HMF synthesis and separation at lower temperatures and shorter duration than previous studies. The main experiment was operated by a semibatch reactor with a continuous flow of CO2. Additionally, three experiments, i) measurement of the partition coefficient of 5-HMF between the two phases, ii) 5-HMF synthesis in H2O–CO2 biphasic batch system, and iii) 5-HMF extraction in H2O–CO2 biphasic semibatch system, were conducted to complement the main experiment. All results from complement experiments were used as parameters in the kinetic modeling. As the result, the maximum yield of 5-HMF (36.6 %) was achieved at a temperature of 403 K, a pressure of 25 MPa, and a reaction time of 180 min. Finally, the optimal conditions for the semibatch experiment for 5-HMF synthesis and separation could be estimated from the kinetic models with parameters determined in this work. The obtained results suggested that this yield can be further improved by increasing the reaction time, which should be confirmed by further experimental studies.

Microwave-Assisted Production of 5-Hydroxymethylfurfural from Fructose Using Sulfamic Acid as a Green Catalyst

The development of safe-by-design synthesis of valuable chemicals from biomass derivatives is a key step towards sustainable chemical transformations in both academia and industry. 5-Hydroxymethylfurfural (5-HMF) is a biomass derivative chemical of high commercial interest due to its wide range of chemical and biofuel applications. In this scenario, the present work contributes to a methodology for producing 5-hydroxymethylfurfural (5-HMF) through fructose dehydration reaction under microwave irradiation. The proposed protocol uses a simple sodium chloride–saturated aqueous-i-PrOH biphasic system and catalysis of sulfamic acid, a low-cost solid Brønsted–Lowry inorganic acid, which presents pivotal features of a sustainable catalyst. A 23 full factorial design was applied to achieve the highest conversion and 5-HMF yield, allowing the identification of the main factors involved in the process. Under the optimized conditions, fructose at the concentration of 120 g L−1 was converted with 91.15 ± 6.98% after 20 min at 180 °C, using 10 mol% of catalyst. 5-HMF was produced in 80.34 ± 8.41% yield and 73.20 ± 8.23% selectivity. Thus, the present contribution discloses a new optimized methodology for converting the biomass derivative fructose to 5-hydroxymethylfurfural (5-HMF).

Clay-supported bio-based Lewis acid ionic liquid as a potent catalyst for the dehydration of fructose to 5-hydroxymthylfurfural

Caffeine and halloysite nanoclay mineral that are bio-based compounds were utilized to synthesize a novel Lewis acid heterogeneous catalyst. To this aim, halloysite was functionalized with 2,4,6-trichloro-1,3,5-triazine and reacted with caffeine, which was then converted to ionic liquid via a reaction with ZnCl2. The catalyst was applied for promoting the dehydration of fructose to 5-hydroxymethylfurfural. To investigate the effects of the reaction variables, response surface methodology was used. The product was achieved in 98.5% in 100 min using a catalyst loading of 30 wt% at 100 °C. Moreover, the catalyst was recyclable up to six runs with slight zinc leaching. Comparison of the catalytic activity of the catalyst with that of halloysite and a control catalyst with one caffeine-based Lewis acid ionic liquid confirmed the superior activity of the former and the important role of 2,4,6-trichloro-1,3,5-triazine for increasing the number of the grafted caffeine and thus the acidic sites of the catalyst. A plausible reaction mechanism was proposed, and the activity of the catalyst for other carbohydrates was also studied. According to the results, this catalyst catalyzed the reaction of other substrates to furnish 5-hydroxymethylfurfural in low to moderate yields. According to the kinetic studies, the activation energy was estimated to be 22.85 kJ/mol.

Aluminum ion intercalation in mesoporous multilayer carbocatalysts promotes the conversion of glucose to 5-hydroxymethylfurfural.

In this study, an efficient modification strategy was proposed by facile loading of trace aluminum ions and p-toluene sulfonic acid (p-TSA) in carbon materials to improve their catalytic activity. p-TSA is then proven to regulate the carbonization process and promote the formation of mesoporous and multilayer structures. The hexa-coordinated aluminum structure is characterized by 1H-27Al solid-state nuclear magnetic resonance (SSNMR) and X-ray photoelectron spectroscopy, which serves as the Lewis-Brønsted acid site in carbocatalysts. Accordingly, the resulting catalyst facilitates a yield of ∼70% for converting glucose to 5-hydroxymethylfurfural (HMF) with a maximum carbon balance of around 91.4% at 150 °C in 6 h. In situ NMR, electrospray ionization mass spectrometry and isotope labeling analysis reveal that the hexa-coordinated aluminum sites promote the isomerization of glucose, and the sulfonic groups facilitate the subsequent dehydration and rehydration of fructose and levoglucosan intermediates. Kinetic models further indicate the decreased energy barrier for glucose conversion over the Al3+/p-TSA intercalated carbocatalyst. This work provides a promising strategy for engineering waste-derived carbocatalysts toward effectively converting carbohydrates to precursors of biofuels and bioplastics.

Intramolecular interaction induced C-C cleavages in fructose conversion in polar aprotic solvents-origin of the formation of excess formic acid and oligomers.

Understanding the mechanism of excess formic acid formation in the dehydration of fructose to HMF would be beneficial to improve HMF selectivity and carbon efficiency. The production of formic acid from keto-D-fructose in polar aprotic solvents, such as THF, DIO, and MTHF, and MIBK solvents without a catalyst was investigated via DFT calculations. It was found that in THF, DIO and MTHF solvents, fructose tended to generate formic acid directly with the catalysis of the intramolecular hydroxyls, especially C6-OH (terminal hydroxyl), while in MIBK, the solvent molecule could react with the intermediates produced in the process, making the barrier of production of acetic acid lower than that of formic acid. Molecular dynamics simulations showed that the lower dielectric polar aprotic solvents (THF, DIO and MTHF) could not destroy the intramolecular H-bonds of hydroxyls in fructose, which could promote the keto-enol tautomerization and hydration steps, facilitating the formation of six-member-ring transition states, which reduced the ring tension and decreased the activation energy greatly, leading to the overproduction of formic acid and oligomers. ETS-NOCV analysis further indicated that the donated electrons from C-O σ-bonds on the carbon chain of fructose made the intramolecular hydroxyls more basic, which could catalyse keto-enol tautomerization with a lower energy barrier than water molecules. To obtain more target products, such as HMF, suitable reaction environments, such as a higher polar aprotic solvent with a low boiling point or restriction of the activity of hydroxyls of fructose, might be selected to destroy the intramolecular interaction and then reduce the overproduction of formic acid and the formation of oligomers.

A simple and efficient synthesis of 5-hydroxymethylfurfural from carbohydrates using acidic ionic liquid grafted on silica gel.

The catalytic application of 3-(4-sulfobutyl)-1H-imidazole-3-ium chloride immobilized on activated silica gel (SiO2-Imi-SO3H) for the production of 5-hydroxymethylfurfural is described here for the first time. This material was synthesized using a three-step method involving the grafting of chloropropyl groups onto activated silica gel, the substitution of zwitterions, and the acidification of zwitterions to form silica-supported ionic liquid. The successful immobilization of the IL on silica gel was confirmed through energy-dispersive X-ray (EDX) spectroscopy, Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and elemental mapping. SiO2-Imi-SO3H-2 demonstrated good catalytic activity and recycling ability in fructose dehydration to 5-HMF. Several conditions for reaction were investigated, and an excellent 5-HMF yield (94.1%) was obtained after 4 h at 160 °C in dimethyl sulfoxide (DMSO) from fructose. Furthermore, a mechanism was proposed, the catalyst's reusability was investigated, and the catalyst was applied for the conversion of glucose to 5-HMF with other metal salts.

Tailored sulfonated carbons: unraveling enhanced catalytic dynamics for fructose dehydration under conventional and microwave heating

Cooperation among active sites within a strongly acidic carbon allowed 80% conversion at 120 °C within a 5-minute reaction period.

One-pot aerobic conversion of fructose to 2,5-diformylfuran using silver-decorated carbon materials

The synthesis of 2,5-diformylfuran (DFF) from fructose is a simultaneous process using two distinct catalysts, including fructose dehydration to 5-hydroxymethylfurfural (5-HMF) accelerated by an acid catalyst, followed by 5-HMF oxidation to DFF mediated by a redox catalyst. In this study, various catalysts with Ag metal decorated on sulfonated amorphous carbon supports (AC-SO3H@Ag) were performed, and their structures were characterized via different characterization techniques such as X-ray diffraction, scanning electron microscopy, X-ray fluorescence spectroscopy, thermogravimetric analysis, Boehm's titration, inductively coupled plasma mass spectroscopy, energy-dispersive X-ray spectroscopy, elemental mapping analysis and Fourier-transform infrared spectroscopy. The catalytic performance of the prepared AC-SO3H@Ag bifunctional catalysts with various wt% of Ag/AC-SO3H was determined for the one-pot transformation of fructose into DFF. The influence of solvent, substrates, reaction time, and catalyst loading were also examined thoroughly to optimize the reaction, and a mechanism was proposed. 5-HMF formed by the dehydration of fructose was converted entirely to DFF, and the highest DFF yield of 77.9 % was obtained after 18 h of reaction time at 150 °C in dimethyl sulfoxide with 3 wt% of the AC-SO3H@Ag catalyst and without the use of any additives, traditional hydrogen acceptors, or oxidants. The reusability of the catalysts was also tested.

Catalytic valorization of biomass carbohydrates into levulinic acid/ester by using bifunctional catalysts

Methyl levulinate (ML) and levulinic acid (LA), important platform chemicals derived from biomass carbohydrates, are potential candidates for use as fuel additives and chemicals. In this work, bifunctional solid acid catalysts were prepared by impregnation via an environmentally friendly method and used for the conversion of glucose to ML and LA. In the conversion of glucose to levulinate, the isomeric conversion of glucose into fructose mainly utilized the Lewis acid sites properties exhibited by chromium, and the dehydration of fructose to 5-hydroxymethylfurfural and its degradation to levulinate mainly exploited the Brønsted acid sites properties exhibited by A15. The yield of ML and LA was 43.1 % and 1.2 %, respectively, and glucose was completely transformed into methanol within 2.0 h at 200 °C. The excellent activity of the best catalyst may be due to the sufficient total acidity and suitable ratio of the number of Lewis acid sites to that of Brønsted acid sites. The results for five catalysis cycles proved that the catalyst has good stability and reusability. In addition, the catalyst prepared was effective for the conversion of other carbohydrates, namely, sucrose, cellobiose, and 5-hydroxymethylfurfural to ML with yields of 83.3 %, 77.7 %, and 57.4 %, respectively.

Organically Functionalized Porous Aluminum Phosphonate for Efficient Synthesis of 5-Hydroxymethylfurfural from Carbohydrates

Naturally occurring fossil fuels are the major resource of energy in our everyday life, but with the huge technological development over the years and subsequent energy demand, the reserve of this energy resource is depleting at an alarming rate, which will challenge our net energy resources in the near future. Thus, an alternative sustainable energy resource involving biomass and bio-refinery has become the most emerging and demanding approach, where biofuels can be derived effectively from abundant biomass via valuable chemical intermediates like 5-hydroxymethylfurfural (5-HMF). 5-HMF is a valuable platform chemical for the synthesis of fuel and fine chemicals. Herein, we report the synthesis of the organically functionalized porous aluminum phosphonate materials: Ph-ALPO-1 in the absence of any template and Ph-ALPO-2 by using 1,3-diaminopropane-N,N,N′,N′-tetraacetic acid as a small organic molecule template and phenylphosphonic acid as a phosphate source. These hybrid phosphonates are used as acid catalysts for the synthesis of 5-HMF from carbohydrates derived from biomass resources. These Ph-ALPO-1 and Ph-ALPO-2 materials catalyzed the dehydration of fructose to 5-HMF with total yields of 74.6% and 90.7%, respectively, in the presence of microwave-assisted optimized reaction conditions.

Mo-based bio-derived carbon catalyst enables a tandem dehydration reaction for the direct synthesis of fuel precursors from fructose

In the pursuit of sustainable alternatives for petroleum fuels, bio-based hydrocarbons emerge as a promising choice. To explore this, a molybdenum catalyst supported on bio-derived carbon was developed, enabling the direct synthesis of fuel precursors from fructose. The catalyst was synthesized by varying the wt.% of molybdenum loading through hydrothermal treatment and carbonization. The NH3-TPD analysis revealed the presence of 1 mmol/g of acidic sites on best the catalyst. HRTEM and XPS analysis reveals that the majority of molybdenum is present as Mo6+. The synthesized catalyst effectively facilitated the dehydration of fructose to 5-hydroxymethylfurfural (5-HMF), followed by hydroxyalkylation/alkylation (DHAA) of 5-HMF with 2-methylfuran. Furthermore, compared to commercial Brønsted acid catalysts, the synthesized catalyst demonstrated remarkable performance, achieving complete fructose conversion with 36% selectivity towards the DHAA product. Moreover, an innovative approach was developed for the separation of 5,5′-((5-((5-methylfuran-2-yl)methyl)furan-2-yl)methylene)bis(2-methylfuran) and 5-HMF from dimethyl sulphoxide (DMSO) using a saturated aqueous sodium chloride (NaCl) solution in tetrahydrofuran (THF). This developed method, utilizing the bio-derived catalyst with efficient catalytic performance and effective product separation from DMSO, shows great promise for directly synthesizing fuel precursors from fructose and advancing sustainable fuel production.

High-yield synthesis of 2,5-Furandicarboxylic acid from fructose via a two-step strategy without 5-Hydroxymethylfurfural isolation using dioxane as a bridging solvent

2,5-Furandicarboxylic acid (FDCA) is a crucial bio-platform molecule for renewable polymers and fine chemicals. Here, a two-step method including fructose dehydration and 5-hydroxymethylfurfural (HMF) oxidation has been reported as an effective strategy to produce FDCA with high yield from fructose directly. In this method, for fructose dehydration over CH3SO3H, tetramethylammonium chloride (TmaCl) was first used as phase modifier and co-solvent in a H2O-dioxane biphasic-solvent system, affording HMF yield up to 90.6 % under mild condition (383 K) with relatively high fructose concentration (e.g. 5–10 wt %). Detailed 13C NMR studies verified the interaction between TmaCl and fructose, which significantly promoted the proportion of fructofuranoses and helped to improve the fructose dehydration activity and HMF yield. After dehydration step, more than 97.8 % of CH3SO3H were recovered in reaction phase for catalyst reuse, while the dioxane solution of extracted HMF was separated via simple phase separation. Followed by water commixing, this HMF dioxane solution (with the HMF concentration of 6.3 wt %) was directly oxidized over Ru/C (393 K, 1 MPa O2) to produce FDCA without HMF isolation and alkali addition, affording FDCA yield near 90 %. This study integrates the fructose dehydration and HMF oxidation rationally via dioxane as the bridging solvent to achieve high FDCA yield without complex HMF purification steps, and thus proposes an applicable model for high-efficient production of FDCA in practice.

Composite of gum arabic and halloysite as a bio-based acidic catalyst for efficient synthesis of 5-hydroxymthylfurfural

A novel acidic bio-based composite has been synthesized via covalent conjugation of two acidic natural compounds, i.e. halloysite clay mineral and Gum Arabic. Measurement of the acidity of the composite confirmed that its acidity was higher than that of individual components. Halloysite-Gum Arabic composite was successfully applied as a biocompatible catalyst for the dehydration of fructose to 5-hydroxymthylfurfural. The reaction conditions were also optimized via Response Surface Method (RSM) and it was found that using 30 mg catalyst per 0.1 mmol fructose led to 99.2% product yield at 100 °C in 105 min. Gratifyingly, the as-prepared composite was recyclable for seven consecutive runs and only insignificant loss of activity was observed after each run. Notably, the recycled catalyst was structurally and morphologically stable.

Synergistic effect of silanols in mesopores leading to unexpected catalysis of dendritic mesoporous silica particles in the aqueous-phase synthesis of 5-hydroxymethylfurfural from fructose

Synthesis of 5-hydroxymethylfurfural (5-HMF) from fructose in water over acids catalysts usually produces unsatisfactorily low yield and selectivity due to inevitable side reactions, i.e., rehydration and condensation. Unprecedentedly, these complications in the aqueous phase synthesis of 5-HMF could be overcome by dendritic mesoporous silica particles (DMSNs). In the hydrothermal reactions of fructose, it was discovered that the synergy of silanols and mesopores transformed seemingly inert DMSNs into active catalysts, leading to a fructose conversion and 5-HMF yield of over 90%. The silanols on DMSNs offered weak Brønsted acid sites for catalyzing the dehydration of fructose to 5-HMF, while undesired reactions were substantially prohibited. The presence of glucose in the reaction suggests that fructose converts to 5-HMF via the acyclic route, and the competing reaction is indeed the isomerization. As revealed experimentally, mesopores full of silanols promoted the conversion of fructose to 5-HMF, but mesopores with a few silanols were relatively hydrophobic, offering a preferential partitioning of 5-HMF in mesopores of DMSNs. DFT analysis theoretically supported that in the presence of silanols, transforming fructose to 5-HMF is thermodynamically more favorable than the isomerization of fructose to glucose.

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

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

Unraveling Structural and Acidic Properties of Al-SBA-15-supported Metal Phosphates: Assessment for Glucose Dehydration.

5-Hydroxymethylfurfural (5-HMF) synthesized through glucose conversion requires Lewis acid (L) site for isomerization and Brønsted acid (B) site for dehydration. The objective of this work is to investigate the influence of the metal type of Al-SBA-15-supported phosphates of Cr, Zr, Nb, Sr, and Sn on glucose conversion to 5-HMF in a NaCl-H2 O/n-butanol biphasic solvent system. The structural and acid property of all supported metal phosphate samples were fully verified by several spectroscopic methods. Among those catalysts, CrPO/Al-SBA-15 provided the best performance with the highest glucose conversion and 5-HMF yield, corresponding to the highest total acidity of 0.65 mmol/g and optimal L/B ratio of 1.88. For CrPO/Al-SBA-15, another critical parameter is the phosphate-to-chromium ratio. Moreover, DFT simulation of glucose conversion to 5-HMF on the surface of the optimized chromium phosphate structure reveals three steps of fructose dehydration on the Brønsted acid site. Finally, the optimum reaction condition, reusability, and leaching test of the best catalyst were determined. CrPO/Al-SBA-15 is a promising catalyst for glucose conversion to high-value-added chemicals in future biorefinery production.