Synthesis Of HMF Research Articles

A highly selective and efficient method for the production of 5-hydroxymethylfurfural from dehydration of fructose using SACS/DES catalytic system

Our findings could have an impact on the synthesis of HMF and the rational design of deep eutectic solvents (DES) for liquid‐phase separations of HMF in biomass processing. Brønsted acidic sites in the case of sulfonated amorphous carbon–silica (SACS) led to excellent selectivity in the dehydration of fructose in deep eutectic solvents. The deep eutectic solvents were found to play a crucial role to suppress the formation of undesired products and make the work-up separation of HMF easier. The combination of amorphous carbon with deep eutectic solvent allowed to conduct a transformation of fructose to HMF with 67% yield and 100% selectivity towards HMF at 110 °C in 4 h. The excellent selectivity, work-up simplification, and recyclable catalytic system provide a cost-effective strategy for the synthesis of HMF.

Synergistic effect of hetero- and homo-catalysts on the ‘green’ synthesis of 5-hydroxymethylfurfural from chitosan biomass

5-Hydroxymethylfurfural (5-HMF) is an important platform chemical and a sustainable choice in the field of biofuels and bioplastics. The past decade has witnessed significant advancements in the production of 5-HMF using edible feedstocks, like glucose and fructose, with good success. In this investigation, we discuss ‘green’ synthesis of 5-HMF from chitosan using a combination of homogenous and heterogeneous catalyses. Catalysts were screened and the effect of various parameters such as concentrations of chitosan and the catalysts, concentration of acetic acid, reaction temperature and reaction time were studied to identify the process conditions giving maximum yield of 5-HMF. It was found that H-β-zeolite in combination with a minimal concentration of acetic acid resulted in maximum yield, which ranges from 15.27 to 28.22% of 5-HMF, depending on the molecular weight of the parent polymer. Our investigation involves usage of solid acid catalysts, environmentally benign solvents and crustacean waste as the starting material making the process ‘green’ and sustainable.

SYNTHESIS OF 5-HYDROXYMETHYLFURFURAL USING IONIC LIQUID [BMIM][BR] FROM RESIDUAL SOYBEAN AND RICE BIOMASSES

In contrast to the major environmental impacts of the petrochemical activity, renewable energy sources have been developing, and among this, biomass has stood out. Among the derivatives obtained from biomass, 5-hydroxymethylfurfural (HMF) is considered a key piece in this process. This work aims at the use of rice and soybean hulls for the synthesis of HMF using the ionic liquid [BMIM][Br], aiming the sustainability of this process. Initially the physical pretreatment of biomass followed by acid hydrolysis was carried out. For the synthesis of HMF, 5ml of the hydrolyzate, 2g of ionic liquid at 120ºC, were used in different reaction times. The results were analyzed by infrared spectrophotometry and by high performance liquid chromatography. The best results in both biomasses were after 2h of reaction reaching a concentration of up to 25 times greater when compared to the hydrolyzate, showing the high potential of ionic liquid [BMIM] [Br] in the synthesis of furanic compounds.
 Keywords: Furanic compounds, raw biomass, ionic liquids.

Selective Dehydration of Glucose into 5-Hydroxymethylfurfural by Ionic Liquid-ZrOCl2 in Isopropanol

In this work, a heterogeneous catalytic system consisting of [HO2CMMIm]Cl and ZrOCl2 in isopropanol is demonstrated to be effective for 5-hydroxymethylfurfural (HMF) synthesis with glucose as the feedstock. Various reaction conditions for HMF synthesis by glucose dehydration were investigated systematically. Under optimized reaction conditions, as high as 43 mol% HMF yield could be achieved. Increasing the water content to a level below 3.17% led to the production of HMF with a higher yield, while a lower HMF yield was observed when the water content was increased above 3.17%. In addition, the data also showed that ZrOCl2 could not only effectively convert glucose into intermediate species (which were not fructose, in contrast to the literature) but also catalyze the intermediate species’ in situ dehydration into HMF. [HO2CMMIm]Cl was used to catalyze the intermediate species’ in situ conversion to HMF. The kinetics data showed that a temperature increase accelerated the intermediate species’ dehydration reaction rate. The reaction of glucose dehydration was a strong endothermal reaction.

Environmental sustainability assessment of HMF and FDCA production from lignocellulosic biomass through life cycle assessment (LCA)

Abstract 2,5-Furandicarboxylic acid (FDCA) and 5-hydroxymethylfurfural (HMF) are top biomass-based platform chemicals with promising potential and an essential part of the future of green chemistry. HMF can be obtained mainly from fructose or glucose. Lignocellulosic glucose has a high production potential from not edible biomass. In the present paper life cycle assessment (LCA) was performed aiming at a better understanding of the environmental performance of the production of FDCA and HMF from lignocellulosic feedstock. Two case studies from the literature were modeled to obtain the life cycle inventory data. The production routes to FDCA comprise seven different process sections: hydrolysis, HMF synthesis, HMF recovery, FDCA synthesis, FDCA flash separation, FDCA purification and HMF boiler. By means of the LCA methodology, solvents such as dimethyl sulfoxide (DMSO) and dichloromethane (DCM), together with the energy demand, were found to be clear critical points in the process. Two scenarios were in focus: Scenario 1 considered the purification of FDCA through crystallization, whereas in Scenario 2 purification was performed through distillation.

Selective hydrodeoxygenation of biomass derived 5-hydroxymethylfurfural over silica supported iridium catalysts

Catalytic performance of iridium supported on SiO2 was investigated for 5-hydroxymethylfurfural (HMF) transformation. Ir/SiO2 catalysts exhibiting different metal loading (1, 3, and 5 wt.%) were tested in the preliminary experiments in the hydrogenation of two probe molecules, e.g. ethyl pyruvate (EP) and ketopantolactone (KP) to evaluate the Ir dispersion on the catalyst activity in CO hydrogenation. In the transformation of HMF the influence of metal dispersion, iridium precursor and addition of H2SO4 were studied revealing that 2,5-bis-(hydroxymethyl)furan (BHMF) was the main product with 83% selectivity at 70% conversion of HMF over chlorine free Ir/SiO2 together with H2SO4 at 333 K in THF under 10 bar H2 pressure. On the other hand, one-pot synthesis of HMF to 2,5-dimethylfuran (DMF) was promoted in the presence of chlorine containing 1%Ir/SiO2(Cl) and H2SO4. Both of these products are considered high value-added chemicals from biomass-derived 5-hydroxymethylfurfural. The exposed iridium atoms together with the total acid sites are an important catalytic descriptor for hydrogenation of HMF to BHMF.

Protonic acid catalysis of sulfonated carbon material: Tunable and selective conversion of fructose in low-boiling point solvent

Catalytic conversion of various carbohydrates into 5-hydroxymethylfurfural (HMF) and 5-ethoxymethylfurfural (EMF) was efficiently conducted by sulfonated carbon material (polyurethane based catalyst, abbreviated as PU-Cat). In the preparation process of catalyst, the tetrahydrofuran was reclaimed. PU-Cat exhibited excellent performance in the synthesis of HMF and EMF from fructose-based carbohydrates. Firstly, the dehydration of fructose into HMF was smoothly carried out in the low-boiling solvent (1, 4-dioxane), which was catalyzed by PU-Cat at 140 °C. The highest yield of HMF was up to 70.1% with full conversion of fructose in 1, 4-dioxane for 2 h. Then, the one-pot conversion of fructose into EMF was also successfully performed in the ethanol/1, 4-dioxane (V/V=70:30) at 140 °C for 2 h, and 66.0% yield of EMF was obtained. Finally, PU-Cat can be recycled five times without significant reduction in catalytic activity.

High Yield Production of 5-Hydroxymethylfurfural from Carbohydrates Over Phosphated TiO2-SiO2 Heterogeneous Catalyst

An efficient and selective process for the conversion of carbohydrates to 5-hydroxymethylfurfural (HMF) was applied over a novel phosphated TiO2-SiO2 (P-TiO2-SiO2) catalyst. The catalyst, synthesized by a facile sol-gel technique, was characterized by X-ray diffraction (XRD), N2 sorption, NH3 temperature-programmed-desorption, and Fourier transform infrared spectroscopy (FT-IR) study of the pyridine adsorbed. The highest HMF yield of 63.0 mol% was achieved at 170 °C for 90 min over P-TiO2-SiO2 catalyst in a tetrahydrofuran (THF)/H2O-NaCl system. The P-TiO2-SiO2 catalyst showed a predominant catalytic performance in the synthesis of HMF, a result of its moderate acid density and suitable Bronsted/Lewis (B/L) acid ratio. Additionally, the catalyst was shown to be efficient in the conversion of more complex cellulose with the high HMF yield of 56.0 mol%. More importantly, this mesoporous catalyst exhibited high stability and recyclability, making it a promising choice for the future production of HMF.

Catalytic Dehydration of Fructose to 5-Hydroxymethylfurfural (HMF) in Low-Boiling Solvent Hexafluoroisopropanol (HFIP).

A mixture of hexafluoroisopropanol (HFIP) and water was used as a new and unknown monophasic reaction solvent for fructose dehydration in order to produce HMF. HFIP is a low-boiling fluorous alcohol (b.p. 58 °C). Hence, HFIP can be recovered cost efficiently by distillation. Different ion-exchange resins were screened for the HFIP/water system in batch experiments. The best results were obtained for acidic macroporous ion-exchange resins, and high HMF yields up to 70% were achieved. The effects of various reaction conditions like initial fructose concentration, catalyst concentration, water content in HFIP, temperature and influence of the catalyst particle size were evaluated. Up to 76% HMF yield was attained at optimized reaction conditions for high initial fructose concentration of 0.5 M (90 g/L). The ion-exchange resin can simply be recovered by filtration and reused several times. This reaction system with HFIP/water as solvent and the ion-exchange resin Lewatit K2420 as catalyst shows excellent performance for HMF synthesis.

Conversion of Fructose to HMF in a Continuous Fixed Bed Reactor with Outstanding Selectivity.

5-Hydroxymethylfurfural (HMF) is a very promising component for bio-based plastics. Efficient synthesis of HMF from biomass is still challenging because of fast degradation of HMF to by-products under formation conditions. Therefore, different studies, conducted mainly in monophasic and biphasic batch systems with and without water addition have been published and are still under investigation. However, to produce HMF at a large scale, a continuous process is preferable. Until now, only a few studies have been published in this context. In this work, it is shown that fluorous alcohol hexafluoroisopropanol (HFIP) can act as superior reaction solvent for HMF synthesis from fructose in a fixed bed reactor. Very high yields of 76% HMF can be achieved in this system under optimized conditions, whilst the catalyst is very stable over several days. Such high yields are only described elsewhere with high boiling reaction solvents like dimethylsulfoxide (DMSO), whereas HFIP with a boiling point of 58 °C is very easy to separate from HMF.

Simple and selective conversion of fructose into HMF using extractive-reaction process in microreactor

An extractive-reaction process for the synthesis of HMF from fructose was implemented in microreactor. Experimental conditions were 10 wt.% fructose in water, MIBK as extracting solvent and HCl as catalyst in a temperature window of 120–160 °C, a MIBK/H2O ratio 1 to 9 and an HCl concentration of 0.25–2 M. The dehydration of fructose to HMF is achieved in less than 40s with a total HMF yield higher than 90% at 150 °C. Aqueous and organic phase spontaneously separate at the outlet of the reactor and HMF is obtained in MIBK with a yield of 80% and a purity of 92%.

One-pot Synthesis of 5-Hydroxymethylfurfural Using a Homogeneous Aqueous Solution of Cellulose (Cellulose-LiBr-H2O) and Combined Metal (II)- Surfactant Catalyst

One-pot synthesis of 5-hydroxymethylfurfural (HMF) from cellulose or glucose through employing a concentrated solution of LiBr as solvent together with a combined metal (II) and surfactant catalyst was studied. First, cellulose was dissolved in the solvent, and then it was hydrolyzed with hydrogen bromide (HBr) under moderate conditions before the solution was neutralized. The next step toward HMF synthesis was performed at 140 °C for 3 h with the addition of the abovementioned catalyst at a 10 mol% level of the substrate. Metal (II) chlorides that could serve as a Lewis acid (i.e., catalysts), or combined metal (II) and surfactant catalysts, were adopted for converting glucose to HMF. The yield of HMF reached 30.5% from glucose, and 33.8% from cellulose when tin (II) dodecylsulfate was used as a Lewis acid catalyst. The catalyst containing tin (II) yielded better results than those that contained zinc (II) or copper (II).

Synthesis of HMF from fructose using Purolite® strong acid catalyst: Comparison between BTR and PBR reactor type for kinetics data acquisition

5-hydroxymethyl-2-furfural (HMF) is an important furanic compound that can be obtained from renewable raw materials. HMF has wide application in the industry, acting as an intermediate in the production of fine chemicals, polymer, biofuels, and pharmaceuticals. In this research, HMF was obtained from the catalytic fructose dehydration. Purolite® SGC650H, a gel-type strongly acidic resin, was applied as a catalyst using dimethylsulfoxide (DMSO) as a solvent. All experiments were carried out in a batch reactor (BTR) and a continuous packed bed reactor (PBR). The reactor performance data showed that increase in temperature resulted in higher HMF yield. In contrast, the higher the fructose concentration, the lower the HMF conversion. The HMF production rates in the PBR were higher because of the concentration of the catalyst. The rate constants were calculated by means of a pseudo-first-order reaction model, and the Arrhenius kinetic parameters obtained changed with regards to the reactants concentrations. The kinetic parameters displayed linear correlation in the Cremer-Constable diagram, which means that the system was under a kinetic compensation effect (KCE); therefore, the model was not suitable to represent the reaction. Langmuir-Hinshelwood (LHHW) models for rate equation were also tested. However all of them failed to adjust to the data, and thus a rate law was not determined. Due to the observed KCE, it was believed that there is at least a set of parallel dehydration reactions initiated from the different fructose isomers which has an influence on kinetic parameters.

Lewis Acid Catalyzed Conversion of 5-Hydroxymethylfurfural to 1,2,4-Benzenetriol, an Overlooked Biobased Compound.

5-Hydroxymethylfurfural (HMF) is a platform chemical that can be produced from renewable carbohydrate sources. HMF can be converted to 1,2,4-benzenetriol (BTO) which after catalytic hydrodeoxygenation provides a route to cyclohexanone and cyclohexanol. This mixture, known as KA oil, is an important feedstock for polymeric products such as nylons which use benzene as feedstock that is obtained from the BTX fraction produced in oil refineries. Therefore, the conversion of HMF to BTO provides a renewable, alternative route toward products such as nylons. However, BTO is usually considered an undesired byproduct in HMF synthesis and is only obtained in small amounts. Here, we show that Lewis acid catalysts can be utilized for the selective conversion of HMF to BTO in subsuper critical water. Overall, up to 54 mol % yield of BTO was achieved at 89% HMF conversion using ZnCl2. ZnCl2 and similarly effective Zn(OTf)2 and Fe(OTf)2 are known as relatively soft Lewis acids. Other Lewis acid like Hf(OTf)4 and Sc(OTf)3 gave increased selectivity toward levulinic acid (up to 33 mol %) instead of BTO, a well-known HMF derivative typically obtained by acid catalysis. Catalytic hydrodeoxygenation of BTO toward cyclohexanone in water was achieved in up to 45% yield using 5 wt % Pd on Al2O3 combined with AlCl3 or Al(OTf)3 as catalysts. Additionally, a mild selective oxygen induced dimerization pathway of BTO to 2,2′,4,4′,5,5′-hexahydroxybiphenyl (5,5′-BTO dimer) was identified.

Microwave-assisted dehydration of fructose and inulin to HMF catalyzed by niobium and zirconium phosphate catalysts

5-Hydroxymethyl-2-furaldehyde (HMF) is a key bio-based platform for the production of renewable monomers and bio-fuels. However, most of its syntheses are carried out under not sustainable conditions. In this work, the production of HMF from fructose and inulin was investigated following the Green Chemistry principles, adopting aqueous medium, appreciable substrate concentration (10wt%), low loading of heterogeneous acid catalyst (niobium or zirconium phosphate) and microwave heating. Both the catalysts resulted very active and promising, in particular zirconium phosphate and the performances were related to their different acid characteristics. The optimization of HMF synthesis with zirconium phosphate was also supported by a statistical modelling, which shows that the highest yield to HMF (about 40mol%) is ascertained at high temperature (190°C) and short reaction time (8min). The catalysts resulted recyclable maintaining their starting activity almost unchanged.

Microwave Assisted Synthesis of 5-Hydroxymethylfurfural from Starch in AlCl3·6H2O/DMSO/[BMIM]Cl System

A successful protocol has been developed for the microwave assisted conversion of corn starch into 5-hydroxymethylfurfural (HMF) utilizing aluminum chloride hexahydrate (AlCl3·6H2O) and 1-butyl-3-methylimidazolium chloride ([BMIM]Cl) ionic liquid. HMF yield as high as 59.8 wt % was achieved at 150 °C within a short reaction time of 20 min. The dimethyl sulfoxide (DMSO)/[BMIM]Cl system was found to be tolerant to optimal water content which influenced the product distribution. Levulinic acid was detected in negligible quantities, and humin content could be controlled by varying different process parameters. Satisfactory results were achieved when waxy corn starch (HMF yield 64.9 wt %) and high amylose corn starch (HMF yield 51.1 wt %) were compared as potential feedstock alternatives to fructose and glucose. The work provided significant insight into the synthesis of HMF in a microwave environment from sustainably sourced biomass such as starch having high amylopectin content.

HMF synthesis in aqueous and organic media under ultrasonication, microwave irradiation and conventional heating

5-Hydroxymethyl furfural (HMF) is known as a noteworthy platform in a biorefinery concept. HMF was prepared via fructose dehydration in aqueous and organic media, using three methods, i.e., conventional heating, ultrasonication and microwave irradiation. Water, methyl isobutyl ketone (MIBK), methyl ethyl ketone and ethyl acetate were used as media for HCl-catalyzed synthesis of HMF. FTIR and 1H-NMR spectroscopies were used for analysis. The synthesis yield and selectivity were investigated to optimize variables such as fructose concentration, catalyst dosage, temperature, irradiation power, solvent, and the reaction atmosphere. It was found that the yield in the organic media was superior to that of the aqueous ones. In addition, nitrogen atmosphere favored higher yield than air, due to lack of HMF oxidation. As conclusion, the highest yields of the conventional, ultrasonicated and microwave-assisted reactions were 87, 53, and 38%, respectively. In the reactions ultrasonically promoted, the reaction time scale was highly reduced from hours to minutes. The yield was varied with treatment times, so that ultrasonication was recognized to be the best approach in terms of yield, while the microwave method was the fastest one. Selectivity varied from 60 to 90% depending the reaction media and promotion method.

Synthesis of 5-hydroxymethylfurfural from fructose catalyzed by phosphotungstic acid

The dehydration of fructose to 5-hydroxymethylfurfural (HMF) is a way to produce a very versatile intermediate of the green chemistry. Heteropolyacid compounds are acid catalysts with singular properties (strong acidity and well-defined structure). This paper aims to analyze the activity of phosphotungstic acid (HPW) and Cs-exchanged phosphotungstic acid (HCsPW) in HMF synthesis, as well as HPW supported on MCM-41. The reactions were conducted in a batch reactor, using dimethyl sulfoxide (DMSO) as solvent, for 2h. The initial tests indicated that HMF is formed in the absence of catalyst, but in presence of the catalysts, the maximum yield to HMF is higher and achieved in less time. The HPW showed promising results, reaching 100% of fructose conversion and 92% of HMF yield, after 30min of reaction at 120°C, with a catalyst:fructose mass ratio of 1:10. However, this heteropolyacid is soluble in DMSO. Besides, the Cs-exchanged HPW resulted in a reduction in HMF yield, because of the reduction in solid acidity. HPW supported in MCM-41 (HPW/MCM) showed to be a good solid acid catalyst for the production of HMF from fructose; moreover, it can be recovered and reused. The variables evaluated for this catalyst were the reaction temperature (100, 120 and 140°C) and the catalyst:fructose mass ratio (1:10; 1:30 and 1:50). The best results obtained for HPW/MCM were 100% of fructose conversion and 80% of HMF yield in 60min, at 120°C.

Organic Carbonates: Efficient Extraction Solvents for the Synthesis of HMF in Aqueous Media with Cerium Phosphates as Catalysts.

We describe a process for the selective conversion of C6 -polyols into 5-hydroxymethylfurfural (5-HMF) in biphasic systems of organic carbonate/water (OC/W), with cerium(IV) phosphates as catalysts. Different reaction parameters such as the OC/W ratio, catalyst loading, reaction time, and temperature, were investigated for the dehydration of fructose. Under the best reaction conditions, a yield of 67.7 % with a selectivity of 93.2 % was achieved at 423 K after 6 h of reaction using [(Ce(PO4)1.5 (H2 O)(H3 O)0.5 (H2 O)0.5)] as the catalyst. A maximum yield of 70 % with the same selectivity was achieved after 12 h. At the end of the reaction, the catalyst was removed by centrifugation, the organic phase was separated from water and evaporated in vacuo (with solvent recovery), and solid 5-HMF was isolated (purity >99 %). The recovery and reuse of the catalyst and the relationship between the structure of the OC and the efficiency of the extraction are discussed. The OC/W system influences the lifetime of the catalysts positively compared to only water.

Experimental and modelling studies on the uncatalysed thermal conversion of inulin to 5-hydroxymethylfurfural and levulinic acid

5-Hydroxymethylfurfural (HMF), an important biobased platform chemical, is accessible by the acid catalysed conversion of biopolymers containing hexoses (cellulose, starch, inulin) and monomeric sugars derived thereof. We here report an experimental study on the uncatalysed, thermal conversion of inulin to HMF in aqueous solutions in a batch set-up. The reactions were conducted in a temperature range of 153–187°C, an inulin loading between 0.03 and 0.12 g/mL and batch times between 18 and 74 min using a central composite experimental design. The highest experimental HMF yield in the process window was 35 wt% (45 mol%), which is 45% of the theoretical maximum (78 wt%). The HMF yields were modeled using a statistical approach and good agreement between experiment data and model was obtained. The possible autocatalytic role of formic acid (FA) and levulinic acid, two main byproducts, was probed by performing reactions in the presence of these acids and it was shown that particularly FA acts as a catalyst. Inulin is an interesting feed for the synthesis of HMF in water. A catalyst is not required, though autocatalytic effects of FA play a major role and also affect reaction rates and product yields.