HMF Yield Research Articles

Conversion of cellulose into 5-hydroxymethylfurfural in an H2O/tetrahydrofuran/cyclohexane biphasic system with Al2(SO4)3 as the catalyst

A simple and efficient biphasic system comprising H2O, tetrahydrofuran (THF), cyclohexane (CHX) and Al2(SO4)3 was employed to convert cellulose into 5-hydroxymethylfurfural (HMF). The volume ratio of the organic phase to the aqueous phase (Vorg/Vaque), concentration of Al2(SO4)3 in the aqueous phase (C[Al2(SO4)3]aque) and concentration of Al2(SO4)3 in the organic phase (C[Al2(SO4)3]org) of the biphasic system played critical roles in the conversion of cellulose into HMF. In the biphasic systems with H2O/THF/Al2(SO4)3 of 4/18/0.4 and H2O/THF/CHX/Al2(SO4)3 of 3/16/3/0.4, > 80% of the added H2O was dissolved in the organic phase, whereas most of the added Al2(SO4)3 remained in the aqueous phase under the reaction temperature, jointly leading to high Vorg/Vaque, high C[Al2(SO4)3]aque and low C[Al2(SO4)3]org in the biphasic system. All of these results yield the excellent performance of these biphasic systems in the conversion of cellulose into HMF. The addition of CHX into the biphasic system can decrease the solubility of Al2(SO4)3 in the organic phase, thus improving the stability of HMF in the reaction system. The influences of catalyst usage, reaction temperature and time, and cellulose/solvent ratio were all explored, and a high HMF yield of 71.2% was obtained in the H2O–THF–CHX biphasic system with an H2O/THF/CHX volume ratio of 3/16/3 under optimized conditions.

Synergistic catalysis of species in molten salt hydrate for conversion of cellulose to 5-hydroxymethylfurfural

The one-pot approach was developed by using molten salt hydrate consisting of ZnCl2·4H2O and LiCl·3H2O to produce 5-hydroxymethylfurfural (5-HMF) from cellulose. Cellulose was dissolved and regenerated to study the interaction of cellulose and molten salt hydrate. The effects of ZnCl2·4H2O concentration, reaction time, and temperature on the conversion of cellulose to 5-HMF were investigated. 5-HMF yield increased when ZnCl2·4H2O was mixed with LiCl·3H2O, and the maximum value (44.1%) was reached at 160 °C and 90 min when ZnCl2·4H2O concentration was 64.9 mol%. The species of ZnCl2·4H2O–LiCl·3H2O were analyzed, and the function of species concentration was correlated with the 5-HMF yield from the conversion of glucose and fructose. It was found that the synergistic catalysis of ZnCl3−, Zn2+, Zn(OH)+, H+ as well as Li+ promoted the efficiently cellulose conversion to 5-HMF.

Glucose Conversion to 5-(Hydroxymethyl)furfural (5-HMF) using Microwave Radiation and Titanium Dioxide

In this project, the focus is placed on the reaction optimizations to produce 5-hydroxymethylfurfural (5-HMF), a common chemical building block to other industrially useful derivatives. The main objective of this study is to determine the feasibility of using different forms of TiO2 as a catalyst to acquire 5-HMF from monosaccharides by an effi cient, economical, and environment-friendly process. The use of three different forms of TiO2 (anatase, rutile, and P-25) as a catalyst, for the glucose dehydration process in this study, has never been reported in past literature. The heating by microwave radiation is introduced to the reaction, which requires elevated temperature, to reduce both the required reaction time and temperature. TiO2, the heterogeneous catalyst for the dehydration mechanism, was fi ltered off, while the 5-HMF dissolved and stayed in the aqueous solution. The three TiO2 catalyst forms are separately utilized to optimize reaction conditions. Anatase form is shown to be the most effective at catalyzing the dehydration process. The reaction temperature of 187 ºC; anatase as a catalyst; and reaction time of 5 minutes led to the optimal outcome in this project. The maximum 5-HMF yield obtained in this study is 12.84%, which is in-between the 6.10-18.60% 5-HMF yield range acquired by Qi et al., 2008. Moreover, a catalyst/substrate weight ratio of 1:10 was used in this study, compared to the 1:2 ratio used by Qi et al., 2008. Hence, this project reduced the amount of catalyst required to obtain a signifi cant 5-HMF yield, and successfully demonstrated that the anatase form of TiO2 is a viable catalyst for the dehydration of monosaccharides to 5-HMF.

Efficient dehydration of fructose into 5-HMF using a weakly-acidic catalyst prepared from a lignin-derived mesoporous carbon

A lignin-derived mesoporous carbon solid acid catalyst (LDMCC) was prepared using alkali lignin as a carbon source and KCl as a salt template to generate a carbon support that was carboxylated with acrylic acid. The prepared LDMCCs were characterized by various spectroscopies (FTIR, XPS, XRD, Raman), porosity determinations (BET), microscopies (SEM, TEM), thermogravimetric analysis, and acid-base titration. The LDMCC produced at the highest carbonization temperature (900 °C) possesses a rich porous structure, high specific surface area (1197.1 m2·g−1), large pore volume (0.63 cm3·g−1), and abundant –COOH groups (2.4 mmol·g−1). This weakly acidic catalyst exhibits excellent synergistic catalytic performance with DMSO in the catalytic dehydration of fructose to prepare 5-hydroxymethylfurfural (5-HMF); the yield of 5-HMF was 96.0% using dimethyl sulfoxide as the solvent, reaction conditions of 180 °C for 2.0 h, and a catalyst loading of 0.1 mg·mg−1. In addition, the prepared LDMCC exhibits excellent reusability over five cycles of use without significant loss in its catalytic activity. This study provides a novel green route for the preparation of a weakly acidic catalyst which may be useful for a variety of biomass conversion processes.

Efficient formation of 5-hydroxymethylfurfural from glucose through H-β zeolite catalyst in the recyclable water-tetrahydrofuran biphasic system

A catalytic system that is both efficient and recyclable is desirable for production 5-hydroxymethylfurfural (HMF) from glucose. In this study, the catalytic system composed of H2O(NaCl)-tetrahydrofuran (THF) biphasic system and H-β zeolite was found to have excellent performance for the glucose conversion into HMF. The physicochemical properties of the H-β zeolite catalyst, the dosage of the system components, and the reaction parameters were investigated in detail to optimize the production efficiency of HMF. Under optimal reaction conditions, an advanced level of 84% HMF yield was obtained from glucose. After the reaction was completed, all components of the catalytic system can be recovered, realizing no waste of reagents. Moreover, the recycled H-β(30) zeolite catalyst maintained considerable catalytic stability after five consecutive cycles. Therefore, it is reasonable to believe that the efficient, inexpensive, and recyclable H2O(NaCl)-THF catalytic system containing H-β(30) zeolite is capable of showing promising application potential in the future.

Production of crude 5-hydroxymethylfurfural from glucose by dual catalysts with functional promoters in low-boiling hybrid solvent

5-Hydroxymethylfurfural (5-HMF) is a value-added versatile platform chemical from renewable biomass resources. In addition to improving the efficiency of catalysts for glucose conversion in reaction media, the product separation and purification represent another significant barrier in large scale production of 5-HMF. In this work, 5-HMF production from carbohydrates using a combination of Lewis and Brønsted acid catalysts was investigated in a low boiling point solvent consisting of ethylene glycol dimethyl ether (GDE) and water, allowing for feasible recycling of catalysts and product separation. High yield (70%) of 5-HMF from glucose is achieved in the presence of reaction additives, isopropanol (IPA) and NaCl, that help to stabilize 5-HMF and promote fructose dehydration, respectively. The results are validated in larger scale (glucose 140 g, reaction volume 2.2 L). To recover product free of the catalysts, the low-boiling polar solvents are evaporated and the crude product containing 80% 5-HMF is recovered by dissolution in a small amount of ethyl acetate (EA) followed by evaporation of EA. This 5-HMF production system offers the advantage of high 5-HMF yield from glucose and the feasibility of product separation.

Roles of Ball Milling Pretreatment and Titanyl Sulfate in the Synthesis of 5-Hydroxymethylfurfural from Cellulose

Production of 5-hydroxymethylfurfural (HMF) from cellulose has been expected for a long time, but most catalytic systems generally give low yield and selectivity due to the difficulty of balancing cellulose deconstruction with the uncontrollable degradation of the target product under harsh conditions. Here we show that the ball milling pretreatment could markedly facilitate the conversion of microcrystalline cellulose to HMF by titanyl sulfate (TiOSO4). The ball milling pretreatment remarkably decreases the degree of crystallinity of microcrystalline cellulose with a reduction of molecular weight via disrupting the hydrogen bond and partially breaking the β-1,4-glycosidic bond. TiOSO4 functions as both Lewis and Brønsted acid to catalyze the efficient conversion of cellulose with high HMF yield (45.4%), far exceeding that (14.1%) from untreated cellulose. The reaction pathway was revealed by liquid chromatograph–mass spectra analysis. In addition, phosphorylated titanium dioxide also afforded a notable HMF yield (21.8%), showcasing the great potential of Ti-based heterogeneous catalyst.

Mechanistic investigation of cellulose formate to 5-hydroxymethylfurfural conversion in DMSO-H2O

5-hydroxymethylfurfural (HMF) primary can be synthesized from monosaccharides including glucose and fructose, cost is one of barriers to realize HMF large-scale production. In this study, a high HMF yield of 69.6 mol% was obtained at 180℃ for 5 min using biomass derived cellulose formate as reactant, which was prepared by formylation of cellulose using recyclable formic acid, and sequentially catalyzed by hydrochloric acid (HCl) and aluminum chloride (AlCl3) in dimethyl sulfoxide (DMSO) and H2O system. To investigate the effect of cosolvents and formyl groups on the cellulose formate conversion, kinetics analysis and molecular dynamics simulations were conducted. Reaction kinetics study shows that the rate constant of hydrolysis of cellulose formate to glucose increased by almost three times in DMSO-H2O and the reaction rates’ constants of glucose, fructose and HMF to humins decreased with the presence of DMSO. Molecular dynamics simulations show that formyl group and DMSO increased its hydrophilicity around the reactive hydroxyl group on the carbon ring and steric hindrance of formyl group affect the distribution of water molecular and DMSO molecular around formylated glucose, resulting in facilitating the formation of a precursor to fructose and inhibiting the formation of humins during formylated glucose conversion.

Numerical Studies on Cellulose Hydrolysis in Organic-Liquid-Solid Phase Systems with a Liquid Membrane Catalysis Model.

The catalytic hydrolysis of cellulose to produce 5-hydroxymethylfurfural (HMF) is a powerful means of biomass resources. The current efficient hydrolysis of cellulose to obtain HMF is dominated by multiphase reaction systems. However, there is still a lack of studies on the synergistic mechanisms and component transport between the various processes of cellulose hydrolysis in a complex multiphase system. In this paper, a liquid membrane catalytic model was developed to simulate the hydrolysis of cellulose and its further reactions, including the adsorption of the liquid membrane on cellulose particles, the consumption of cellulose solid particles, the complex chemical reactions in the liquid membrane, and the transfer of HMF at the phase interface. The simulations show the synergistic effect between cellulose hydrolysis and multiphase mass transfer. We defined an indicator () to characterize the sensitivity of HMF yield to the initial liquid membrane thickness at different reaction stages. decreased gradually when the glucose conversion increased from 0 to 80%, and increased with the thickening of the initial liquid membrane thickness. It was shown that the thickening of the initial liquid membrane thickness promoted the HMF yield under the same glucose conversion. In summary, our results reveal the mechanism of the interaction between multiple physicochemical processes of the cellulose liquid membrane reaction system.

Synthesis of 5-hydroxymethylfurfural from glucose and fructose using a Brønsted acid-linked amorphous carbon catalyst

In recent years, carbon-based solid acid catalysts have attracted a lot of attention because they meet the environmentally friendly and sustainability criteria of "green chemistry". Following that trend, in this work, the carbon-based solid acid catalyst (BM-pTSA) was successfully prepared via two-step process: bagasse pre-treatment followed by hydrothermal carbonization using as-activated carbon and p-toluenesulfonic acid. The morphology and structure of the catalyst were determined based on FT-IR, TGA, XRD and EDX spectroscopy results. The investigation of BM-pTSA activity was carried out on the synthesis of 5-hydroxymethylfurfural (5-HMF) from glucose and fructose using DMSO as solvent. The yield of 5-HMF was monitored for 16 h of reaction with temperature variationat at 80ºC, 100ºC, 120ºC for fructose and at 100ºC, 120ºC and 140ºC for glucose. Catalyst dosage investigation was also performed with 1 mg, 5 mg, 10 mg, 15 mg and 20 mg of BM-pTSA. The results show that the catalyst has a low efficiency for glucose conversion (below 13% 5-HMF) because it contains only Brønsted acid sites. The highest 5-HMF yield achieved in this study was 88,50% in the transformation of fructose with 1 mg catalyst at 120ºC, 12 h. Even so, from an economic point of view, we estimate that the most optimal reaction conditions are at 120ºC with 1 mmol fructose, 1 g DMSO and 5 mg BM-pTSA which generates a yield of 5-HMF was 67,91% after only 4 h of reaction.

Conversion of bio-carbohydrates to 5-hydroxymethylfurfural in three-component deep eutectic solvent.

5-Hydroxymethylfurfural (HMF) is a valuable platform chemical derived from biomass and lots of research focuses on the synthesis of HMF from fructose and glucose. Herein, conversion of bio-carbohydrates to 5-hydroxymethylfurfural (HMF) was studied in the three-component deep eutectic solvent (DES) system, which was composed of choline chloride (ChCl), boric acid and substrates such as fructose, glucose and sucrose. Bio-carbohydrates handled under typical reaction conditions gave satisfactory conversion (44% for fructose and 31% for glucose) and yield of HMF (35% for fructose and 21% for glucose) in 1 h. Moreover, owing to the benefits of DES, the initial substrate content could be higher and the reaction temperature could be reduced, thus side reactions were effectively avoided and the selectivity of HMF was better (ranging from 79% to 100% for fructose and from 65% to 100% for glucose). We believe this method could provide a promising alternative for conversion of bio-carbohydrates to HMF and a better utilization of biomass.

Advance of glucose conversion to 5-hydroxymethylfurfural using ionic liquid: mini review

Biomass has been used as a raw material to replace fossil fuel due to its abundance and renewability in recent years. The majority of biomass consists of carbohydrates such as glucose and fructose. The conversion of glucose into its derivative (i.e., 5-hydroxymethylfurfural (HMF)) opens several spaces to be studied. However, the yield of HMF is still low due to its ease of degradation into by-products and the difficulty of product separation. Therefore, ionic liquid (IL) is used as a solvent or media to avoid HMF degradation, which has high thermal stability, low toxicity, an un-flammable, wide range of solubility, physical and chemical stability. In addition, IL is recyclable, has good performance at dissolving biomass, and can act as a catalyst. Many important aspects of glucose conversion into HMF in IL as a media and catalyst can be deeply developed and investigated regarding conversion yield, which is affected by different ILs used, and conversion time. This review paper will discuss a detailed summary of the development of glucose conversion into HMF using IL.

Preparation of 5-hydroxymethylfurfural using magnetic Fe3O4@SiO2@mSiO2-TaOPO4 catalyst in 2-pentanol.

5-Hydroxymethylfurfural (HMF) is one of the most important platform molecules and could be transformed into a variety of fuel additives and high value-added chemicals. Multiple catalyst systems have been developed for the conversion of carbohydrates to HMF, but there are still unavoidable problems, including high temperature and pressure, difficult recovery of solvent, corrosion of equipment, poor catalyst circulation, etc. Herein, a new magnetic Fe3O4@SiO2@mSiO2-TaOPO4 catalyst for the preparation of HMF from fructose in 2-pentanol was developed. The structures of the catalysts were characterized by FT-IR, TSM, EDS, SEM, XRD and VSM. The 2-pentanol solvent is not only conducive to the production of HMF, but also enables the reaction to be carried out at a lower pressure. The highest yield of HMF (85.4%) was obtained using 20 wt% catalyst under 10% substrate concentration (0.5 g of fructose) at 120 °C for 3 h. The catalysts can be easily separated by magnetism. The slight decrease in catalyst activity after 7 cycles was mainly due to the loss of catalyst during the cycle operation. Simultaneously, the total yield of HMF was 51.3% after scale-up to 15 g of fructose, showing the possible industrial application potential of this catalyst system.

Ultrasound Assisted Pretreatments Applied to Cupuaçu Husk (Theobroma grandiflorum) from Brazilian Legal Amazon for Biorefinery Concept

Cupuaçu husk (CH) is the waste of a common fruit from a native species of the Brazilian Legal Amazon. The current study investigated the influence of ultrasound (US) combined with aqueous, acid, alkaline, and ionic liquid (IL) pretreatments on the chemical and physical aspects of CH and the yield of chemical platforms production, 5-hydroxymethylfurfural (HMF) and furfural (FF), using IL. Scanning electron microscopy, X-ray diffraction (XRD) and Fourier transform infrared spectroscopy were used to feature the raw and pretreated biomass. The highest levels of glucose (9.90 g L-1) were observed in the liquid fraction resulting from the acid + US pretreatment followed by acid hydrolysis. The IL + US pretreatment recorded the best performance in removing lignin. Based on XRD analyses, ultrasound increased crystallinity of all pretreated samples as a result of the removal of cellulose’s amorphous fraction. However, it promoted accessibility to adopted reagents by increasing biomass exposure due to cavitation. The best yields of HMF and FF were recorded from hydrolysis of the solid fraction resulting from the acid + US (12.94%) and alkaline + US (48.84%) pretreatment, respectively. These results indicate satisfactory performance of ultrasound assisted pretreatments to the simplified and economic conversion of biomass into value-added products.

Ag substituted Au clusters supported on Mg-Al-hydrotalcite for highly efficient base-free aerobic oxidation of 5-hydroxymethylfurfural to 2,5-furandicarboxylic acid

A highly active and selective Au20Ag/MgAl-300 catalyst was developed for HMF oxidation to FDCA under base-free reaction conditions using molecular oxygen as the oxidant, with high conversion of HMF (100%) and high yield of FDCA (>95%).

Insight into the dehydration of high-concentration fructose to 5-hydroxymethylfurfural in oxygen-containing polar aprotic solvents

A high 5-HMF yield of 85.4% was achieved in polar aprotic oxygen-containing solvent with strong electrophilic maleic acid by quenching DHH.

Green synthesis of 5-hydroxymethylfurfural through non-catalytic conversion of glucose in a microreactor

• Green continuous 5-HMF synthesis from glucose was proposed. • 5-HMF yield of 69.5% and selectivity of 77.9% were achieved. • The optimization models on yield and selectivity were determined. • High performance of our process was reported when compared to other processes. • Kinetic mechanism of our process was proposed and evaluated. 5-hydroxymethylfurfural (HMF) is an essential platform chemical that can be transformed into various high-value-added products. Most of the 5-HMF production nowadays involves the use of catalyst, which significantly contributes to the production cost as well as the environmental problem concerning highly acidic compounds. Moreover, the low 5-HMF yield has been recognized as a bottleneck, reducing its attractiveness. In this work, the enhancement of continuous green synthesis of 5-HMF from glucose in a biphasic microreactor was proposed. Methyl isobutyl ketone (MIBK) was used as an organic solvent to prevent further reactions of 5-HMF into undesired products. The main and interaction effects of reaction temperature, residence time, and organic-to-aqueous volumetric ratio on 5-HMF yield were studied. The 5-HMF yield of 69.5% and 5-HMF selectivity of 77.9% were achieved at the reaction temperature of 190 °C, residence time of 134 mins, and organic-to-aqueous volumetric ratio of 0.5:1. The kinetic parameters were estimated to predict the concentration profiles. It was found that our environmentally-friendly process provided a similar yield of 5-HMF compared to those of the conventional techniques (literature data).

Sulfated zirconia catalysts supported on mesoporous Mg-SBA-15 with different morphologies for highly efficient conversion of fructose to 5-hydroxymethylfurfural

In this work, the novel acid-base bi-functional mesoporous SBA-15 catalysts with four kinds of morphologies were synthesized by Mg incorporated and sulfated zirconia (SZ) grafted. The introduction of Mg to mesoporous SBA-15 materials significantly improves the strength of the base. And the supported SZ group exhibit effective Brønsted/Lewis acid strength. The physical and chemical properties of the prepared materials were systematically analyzed by the characterization tests of SEM, TEM, XRD, N 2 adsorption-desorption of, FT-IR, TGA, XPS, NH 3 /CO 2 -TPD and in-suit PY-IR. The obtained catalysts of SZ@Mg-SBA-15 could be applied to the fructose conversion into 5-hydroxymethylfurfural (5-HMF) with the co-solvent system of iPrOH/DMSO ( v / v = 9:1). 5-HMF was achieved under the optimal reaction condition with the highest yield of 98.6%. The result shows that the reaction of fructose dehydration into 5-HMF could be caused by the combination of Brønsted acid site and basic site. This work developed reaction system could avoid the large use of environmentally dangerous solvents, and provides a new economical and feasible method for the large-scale conversion of fructose biomass. • Mesoporous SZ@Mg-SBA-15 catalysts were successfully synthesized. • The acid-base bifunctional sites showed synergistic effects in catalytic activity. • The highest 5-HMF yields of 98.6% can be obtained from fructose. • The developed iPrOH/DMSO co-solvent has a minimal environmental impact. • The prepared catalyst can be reused without significant loss of activity.

Preparation of functionalized diallylimidazole ionic liquid and its application in conversion of D-fructose into HMF

A kind of functionalized diallylimidazole ionic liquids (CnDAIMF) was synthesized and applied in the dehydration of D-fructose to produce 5-HMF under the microwave radiation. The results showed that X-ray, 1H NMR and FT-IR confirmed the production. The target ILs existed in a highly centrally symmetric, and crystalline state at room temperature, with a good thermal stability up to 300 °C (HTD ≥ 340 °C). In the experiments of conversion D-fructose to 5-HMF, 5-HMF could be obtained via the catalysis of diallylimidazole IL whether in water or DMSO. The catalytic performance of these ILs was not much different from that of solid acid (like camphor sulfonic acid or solid carbon sulfonic acid), and which was higher than that of the monoimidazole hexafluorophosphate or imidazole class bromine salt, but there were no obvious changes can be found with the variation of carbon chain length between imidazole rings in diallylimidazole IL. The effects of temperature and solvent on the reaction were more significant. The optimized yield of 5-HMF was 52.59% at 185 °C in a water-C2DAIMF solvent (t = 10 min), while 73.71% at 195 °C in DMSO-C2DAIMF solvent. Furthermore, six CnDAIMF have a considerable effect on the conversion in water and 5-HMF yield of about 50% could be obtained, which is satisfactory compared with other similar processes, especially in the microwave system of aqueous solution. Therefore, this process may be benefit for many researches and applications related to functionalized ionic liquid research and biomass conversion applications.

Reaction Mechanism of the Microwave-Assisted Synthesis of 5-Hydroxymethylfurfural from Sucrose in Sugar Beet Molasses

5-hydroxymethylfurfural (HMF) stands out among the chemical products derived from biomass as a building block in the chemical industry. The conventional production of HMF is usually carried out from fructose, glucose, or other monosaccharides as feedstock, but sugar beet molasses, a by-product of the sugar industry containing sucrose (45–55%), is promising. This exploratory study used three aqueous stock solutions and one biphasic system as the sources of sucrose. The dehydration of sucrose to 5-hydroxymethylfurfural was assisted by microwave heating and subcritical water conditions. The maximum yield of HMF was 27.8 mol % for the aqueous solution of synthetic sucrose at 80 min of treatment. Although HMF yield was 7.1 mol % in the aqueous sugar beet molasses solution, it increased 2-fold after clarification (15.1 mol %) and 1.6-fold in the biphasic system (11.4 mol %). These are favorable outcomes since this is an exploratory investigation. The pseudo-first-order model fitted experimental data from the conversion of the sucrose from the stock solutions, and kinetic parameters were estimated and compared. The estimated reaction rate constant showed that inversion of sucrose is faster than fructose dehydration to HMF, but the latter reaction was the rate-determining step only for the biphasic system. The maximum partition coefficient value was four between 40 min and 60 min of reaction, calculated at room temperature. These predictions help investigators to estimate conversions and selectivity when pilot plants need to be simulated.