HMF Yield Research Articles

Efficient conversion of corn stover to 5-hydroxymethylfurfural and furfural using a novel acidic resin catalyst in water-1, 4-dioxane system

A route of corn stover conversion was developed for 5-hydroxymethylfurfural (5-HMF) and furfural production by a novel Cl-containing resin-based solid acid catalyst (Cl0.3-S-R), which was synthetized by a simple hydrothermal method through polymerization reaction of o-chlorophenol and p-hydroxybenzenesulfonic with formaldehyde. The effects of catalyst types, reaction time, substrate types, solvent types, additional water concentrations and corn stover concentrations were investigated in detail. The high 5-HMF yield of 43.8% and furfural yield of 38.1% (based on the xylose and glucose units) could be achieved from corn stover simultaneously in water/1,4-dioxane at 190 °C in 80 min, with Cl0.3-S-R as catalyst. Furthermore, the catalysts were characterized by SEM, elemental analysis, FTIR, XPS and N2 adsorption-desorption to reveal its physical and chemical properties.

Intensified reactive extraction for the acid-catalyzed conversion of fructose to 5-hydroxymethyl furfural

We conduct an experimental study of fructose dehydration to 5-hydroxymethyl furfural (HMF) in a biphasic microreactor as a function of residence time, temperature, and sugar loading using methyl butyl iso-ketone (MIBK) and 2-pentanol as extracting solvents. We demonstrate stable operation with maximum HMF yields of 93% and 87% in the two solvents, respectively, at 200 °C and a residence time of 2 s for a 5 wt% fructose aqueous feed. We report the highest optimal HMF space–time yield of 60 kg/L-hr at 200 °C (10 – 2,500-fold higher than published reports). Unexpectedly, an optimum organic-to-water ratio exists that depends on the solvent. Notably, we observe experimentally an increased fructose rate and HMF yield well above the extraction thermodynamic limit and hypothesize that the solvent plays a dual role, that of an extractant to protect HMF from degradation and a modifier of the fundamental chemistry. We expose mass transfer limitations of microreactors at longer residence times and higher temperatures and provide reactivity maps for their design. We show that batch reactors are unfit for high throughput and distributed manufacturing where small, farm-based systems are necessary.

Microporous and mesoporous structure catalysts for the production of 5‐hydroxymethylfurfural (5‐HMF)

In recent years, researchers have gained attention in finding new strategies for alternative renewable energy resources in reducing the dependency on fossil fuel in providing energy to the world. 5-Hydroxymethylfurfural (HMF) is one of the most promising chemicals as it is a multi-functional compound and an intermediate compound that is beneficial in numerous chemical and fuel applications. This study provides recent progress on developing high yield and selectivity of HMF using hydrothermal reaction, emphasizing the catalytic performance efficiency of the developing structured catalysts from a technical perspective. We highlighted a few critical factors and parameters in maximizing the synthesis of HMF by selectively optimizing the desired kinetic reactions, which are hydrolysis, isomerization, and dehydration of sugars, and limiting the undesired side reactions, including HMF rehydration and depolymerization. The use of different types of microporous and mesoporous catalysts provides different HMF conversion results, and by applying few parameters, including catalyst: substrate ratio, Lewis: Brønsted acid ratio, reaction temperature, and duration of reaction, can be tunable in achieving maximum HMF yield and selectivity.

Synthesis of bifunctional tin-based silica–carbon catalysts, Sn/KIT-1/C, with tunable acid sites for the catalytic transformation of glucose into 5-hydroxymethylfurfural

Catalytic transformation of carbohydrates to bio-chemicals such as 5-Hydroxymethylfurfural (HMF) has become a hot research topic, but development of cost-effective/efficient catalysts and processes remains a challenge for industrial application. In this study, efficient bifunctional Sn/KIT-1/C catalysts with controllable acid sites were synthesized and applied for glucose-to-HMF conversion. Strong Lewis acid sites were introduced into the framework of disordered mesoporous silica by liquid-phase grafting of tin chloride, and Bronsted acid sites were generated by inserting carbon into the mesopores, followed by controlled oxidation of the carbon. Characterizations revealed that optimizing the amount of carbon source, and carbonization and oxidation temperature provided a proper amount and strength of acidity that could significantly catalyze glucose dehydration reaction to HMF with suppressed byproducts formation. The best catalyst Sn/KIT-1/C(75–400-300) demonstrated superior catalytic performance at 175 °C for 2 h under THF/H2O biphasic system, obtaining 78.4 ± 2.1% and 82.9 ± 2.4% HMF yield and selectivity, respectively. The high activity may be attributed to catalyst high surface area/porosity, and the presence of well-balanced amounts and strength of Lewis/Bronsted acid sites. The catalyst could maintain its excellent catalytic activity for five consecutive runs, suggesting the high physical–chemical stability of the catalyst. The results obtained in this work demonstrated that bifunctional metal-supported silica–carbon composites can be a promising catalyst for simple/complex carbohydrates conversion to HMF/bio-based chemicals.

Effect of mechano-chemical pretreatment on valorizing plant waste for 5-hydroxymethylfurfural under microwave hydrothermal treatment

Plant waste (PW) is a common and abundant renewable biomass resource whose total amount is constantly increasing and accounts for up to 50% of municipal solid waste. This study aims to develop a valorization method for PW. A two-stage treatment method combining mechanical ball milling (BM) and microwave hydrothermal treatment (MHT) was investigated. BM can effectively destroy the crystallization of cellulose and reduce the particle size to increase the specific surface area and improve the MHT efficiency. The BM-MHT process could improve the 5-hydroxymethylfurfural (HMF), which is significantly higher than physical methods like grinding, ultrasonic and liquid nitrogen treatment. The BM conditions were further optimized by using a Box-Behnken Design with response surface methodology. The model showed that the highest HMF yield could reach 1.8% at 150 °C in MHT process after BM. An economic analysis indicated that BM-MHT offers a green treatment method with great economic benefits. It provides a novel valorization strategy for organic waste like PW.

Evaluating the potential of the microwave hydrothermal method for valorizing food waste by producing 5-hydroxymethylfurfural

5-Hydroxymethylfurfural (HMF) is a platform compound with a high added value derived from biomass. In this study, microwave hydrothermal treatment (MHT) was used to produce HMF from food waste (FW). By optimizing the holding temperature (230 °C) and the holding time (15 min), an HMF yield of 4.61 wt% was obtained, the highest value yet achieved. The main HMF precursors exhibited different phenomena: the fructose content decreased as the holding temperature and holding time increased, while the glucose content first increased then decreased. It was proved that the potential profit of HMF production from FW by MHT was 10,674 USD/tonne, and the resource productivity was 60 to 1000 times that of other valorization methods. MHT is a feasible strategy for valorizing FW by producing the high added value product, HMF.

Synthesis, characterization and catalytic activity estimation of WO3/MeO2 (Me: Zr, Ti, Si) oxides for fructose conversion reaction into 5-hydroxymethylfurfural

Series of WO3/MeO2(Me: Zr, Ti, Si) oxides were synthesized by impregnationmethod with 1:9 atomic ration of W:Me.The oxides were characterized by various techniques such as XRD, IR. The XRD patterns showed the crystalline structure of ZrO2, TiO2,WO3 and amorphous of SiO2. They were formed in tetragonal, anatase, monoclinic phase structure. All oxide and mixed oxides were estimated its catalytic activity through fructose conversion into 5-hydroxymethylfurfural in DMSO solvent. The results indicated that all mixed oxides owned good catalytic activity for the reaction in comparison with case of only presence DMSO solvent. Especially, The oxide WO3/ZrO2 showed the best HMF yield, 81,6%, at experimental conditions. This property could be due to the well dispersionand acidity of nano cluster WO3 on the surface s of oxides MeO2.

Catalytic dehydration of fructose into 5-hydroxymethylfurfural by propyl sulfonic acid functionalized magnetic graphene oxide nanocomposite

Covalent immobilization of propyl sulfonic acid groups on the surface of magnetic graphene oxide is reported as an efficient magnetically recoverable solid acid catalyst for the conversion of fructose into 5-hydroxymethylfurfural (5-HMF). The obtained nanocomposite has advantages of both graphene oxide (high surface area) and magnetic nanoparticles (fast and facile separation by a magnet). The numerous reaction parameters including solvent, reaction time, temperature, and amount of catalyst were optimized to attain maximum yield of 5-HMF. The results revealed that fructose could be effectively transformed into 5-HMF with a yield of 87% under the optimized reaction conditions. The catalyst could be magnetically separated from the reaction mixture. Moreover, the catalyst exhibited high stability and could be reused for at least five times without a discernible loss of catalytic performance.

Catalytic conversion of whey permeate into 5-hydroxymethylfurfural: Optimization and kinetic modeling approach

This work presents an efficient catalytic system for the valorization of whey permeate into 5-hydroxymethylfurfural (HMF). Lactose was studied as the model carbohydrate. The side products formed during the reaction were levulinic acid (LA), formic acid (FA), and humins. It was found that 0.25 mol/L of acetic acid and 0.21 mol/L of AlCl3·6H2O showed a synergistic effect on the HMF yield in γ-valerolactone and water as the binary solvent system. Three independent reaction parameters (reaction temperature, time, and AlCl3·6H2O concentration) were investigated to understand their effects on the formation of HMF, LA, and FA. The maximum HMF yield (59 mol%) for lactose was obtained at the optimum conditions (135 °C, 100 min, and 0.21 mol/L AlCl3·6H2O). The developed catalytic system was applied on different concentrations of whey permeates namely, whey permeate, ultrafiltered whey permeate, combined reverse osmosis-nanofiltered whey permeate after 30% evaporation, and whey permeate powder. Amongst all, the application of the developed catalytic system on whey permeate powder showed promising results, where 74 mol% HMF yield was obtained in a shorter reaction time (40 min) than lactose. The kinetic study demonstrated all the possible reaction pathways occurring during HMF formation for lactose and whey permeate powder. Key findingThe reaction kinetics for whey permeate powder discloses various possible reaction pathways for lactose to HMF conversion.

Solid acid catalyst prepared via one-step microwave-assisted hydrothermal carbonization: Enhanced stability towards intensified production of 5-hydroxymethylfurfural in water/γ-valerolactone/NaCl

• C-SO 3 H was effectively prepared by MW assisted one-step hydrothermal process. • The catalyst promoted the reactivity of glucose dehydration to HMF. • HMF yield was further enhanced by use of a benign water/GVL/NaCl biphasic system. • The catalyst possessed excellent reusability for glucose dehydration. In this study, carbon-based catalysts prepared via one-step microwave (MW)-assisted hydrothermal carbonization, functionalized with 2-hydroxyethylsulfonic acid (HESA) and hydrochloric acid (HCl), were tested on the intensified production of HMF from dehydration of glucose in biphasic system, consisting of water/γ-valerolactone/NaCl. The highest HMF yield (51.61%) was obtained when using 40/60 %v/v of water/ γ-valerolactone (GVL), C-SO 3 H catalyst loading at 0.5% by weight (%wt) of glucose, at 180°C for 45 min. In addition, the one-step preparation applying MW irradiation provided the catalyst with excellent reusability up to at least five times.

5-HMF production from industrial grade sugar syrups derived from corn and wood using niobium phosphate catalyst in a biphasic continuous-flow tubular reactor

This work demonstrated the promise of using industrial-grade sugar syrups derived from corn and wood, i.e., high fructose corn syrup (HFCS), glucose corn syrup (GCS) and wood-based sugar (TMP-Bio Sugar), as cheaper and competitive feedstocks for 5-HMF production using niobium phosphate as a heterogeneous solid acid catalyst in a biphasic continuous-flow tubular reactor. 5-HMF yield as high as 53.1% with 100% sugar (glucose and fructose) conversion was obtained from catalytic dehydration of HFCS-90 (containing 90 wt% fructose) at 150 °C, with feed concentration of 200 mg/ml (glucose and fructose) and aqueous to organic phase ratio of 1:5 (v/v). Catalyst stability with time was tested over 20 h of continuous-time on stream, and the reusability of the catalyst was studied after in-situ regeneration of the used catalyst by calcination in the air for removing the deposited humins and coke on the surface of the catalyst particles. The regenerated catalyst showed good activity with almost constant selectivity, although at lower glucose conversion and reduced 5-HMF yield compared to the fresh catalyst, indicating that the in-situ regeneration process could recover a part of the acid sites on the catalyst surface. The produced humins during the reaction were characterized by Fourier transform infrared spectrometry (FT-IR), thermogravimetric analysis (TGA) and elemental analysis (CHNS). The results showed high aromaticity and the presence of a high degree of unsaturated compounds in the structure of humins.

Glucose Conversion into 5-Hydroxymethylfurfural over Niobium Oxides Supported on Natural Rubber-Derived Carbon/Silica Nanocomposite

5-Hydroxymethylfurfural (HMF) is one of the most important lignocellulosic biomass-derived platform molecules for production of renewable fuel additives, liquid hydrocarbon fuels, and value-added chemicals. The present work developed niobium oxides (Nb2O5) supported on mesoporous carbon/silica nanocomposite (MCS), as novel solid base catalyst for synthesis of HMF via one-pot glucose conversion in a biphasic solvent. The MCS material was prepared via carbonization using natural rubber dispersed in hexagonal mesoporous silica (HMS) as a precursor. The Nb2O5 supported on MCS (Nb/MCS) catalyst with an niobium (Nb) loading amount of 10 wt.% (10-Nb/MCS) was characterized by high dispersion, and so tiny crystallites of Nb2O5, on the MCS surface, good textural properties, and the presence of Bronsted and Lewis acid sites with weak-to-medium strength. By varying the Nb loading amount, the crystallite size of Nb2O5 and molar ratio of Bronsted/Lewis acidity could be tuned. When compared to the pure silica HMS-supported Nb catalyst, the Nb/MCS material showed a superior glucose conversion and HMF yield. The highest HMF yield of 57.5% was achieved at 93.2% glucose conversion when using 10-Nb/MCS as catalyst (5 wt.% loading with respect to the mass of glucose) at 190 °C for 1 h. Furthermore, 10-Nb/MCS had excellent catalytic stability, being reused in the reaction for five consecutive cycles during which both the glucose conversion and HMF yield were insignificantly changed. Its superior performance was ascribed to the suitable ratio of Brønsted/Lewis acid sites, and the hydrophobic properties generated from the carbon moieties dispersed in the MCS nanocomposite.

Directional synthesis of furfural compounds from holocellulose catalyzed by sulfamic acid

The coproduction of 5-hydroxymethylfurfural (5-HMF) and furfural (FUR) via the direct hydrolysis of holocellulose analogue composed of cellulose and hemicellulose was investigated. The effects of catalyst amount, solvent type and amount, reaction temperature and time using sulfamic acid with dual active sites as catalyst were also studied. The yields of 5-HMF and FUR at 37.2% and 62.0% were obtained with the volume ratio of γ-valerolactone to water of 25:1 at 180 °C for 3 h. The conversion of corn cob holocellulose and wheat straw holocellulose to furfural compounds was then carried out under the identical conditions. Yields of 5-HMF at 26.6% and 28.5%, and yields of FUR at 34.5% and 26.1% were obtained, respectively. A possible mechanism for the coproduction of 5-HMF and FUR from holocellulose was proposed. It is believed that there is a synergistic effect between the hydrolysis of cellulose and hemicellulose during the conversion of holocellulose.Graphic abstract

Catalytic Dehydration of Fructose to 5-Hydroxymethylfurfural in Aqueous Medium over Nb2O5-Based Catalysts.

The catalytic dehydration of fructose to 5-hydroxymethylfurfural (HMF) in water was performed in the presence of pristine Nb2O5 and composites containing Nb and Ti, Ce or Zr oxides. In all experiments, fructose was converted to HMF using water as the solvent. The catalysts were characterized by powder X-ray diffraction, scanning electron microscopy, N2 physical adsorption, infrared and Raman spectroscopy and temperature-programmed desorption of NH3. Experimental parameters such as fructose initial concentration, volume of the reacting suspension, operation temperature, reaction time and amount of catalyst were tuned in order to optimize the catalytic reaction process. The highest selectivity to HMF was ca. 80% in the presence of 0.5 g·L−1 of bare Nb2O5, Nb2O5-TiO2 or Nb2O5-CeO2 with a maximum fructose conversion of ca. 70%. However, the best compromise between high conversion and high selectivity was reached by using 1 g·L−1 of pristine Nb2O5. Indeed, the best result was obtained in the presence of Nb2O5, with a fructose conversion of 76% and a selectivity to HMF of 75%, corresponding to the highest HMF yield (57%). This result was obtained at a temperature of 165° in an autoclave after three hours of reaction by using 6 mL of 1 M fructose suspension with a catalyst amount equal to 1 g·L−1.

Pressure Reduction Enhancing the Production of 5-Hydroxymethylfurfural from Glucose in Aqueous Phase Catalysis System.

5-hydroxymethylfurfural (HMF) obtained from biomass is an important platform chemical for the next generation of plastics and biofuel production. Although industrialized, the high yield of HMF in aqueous systems was rarely achieved. The main problem is that HMF tends to form byproducts when co-adsorbed with water at acid sites. In this study, the pressure was reduced to improve the maximum yield of HMF from 9.3 to 35.2% (at 190 °C in 60 min) in a glucose aqueous solution. The mechanism here involved water boiling as caused by pressure reduction, which in turn promoted the desorption of HMF from the solid catalyst, thereby inhibiting the side reaction of HMF. Furthermore, the solid catalysts could be reused three times without a significant loss of their catalytic activity. Overall, this work provides an effective strategy to improve the yield of HMF in water over heterogeneous catalysts in practice.

Catalytic coupling boosting efficient production of 5‐hydroxymethylfurfural from glucose

AbstractAs a novel green chemical building block, it is of significance to increase the productivity of 5‐hydroxymethylfurfural (HMF) derived from hexoses. In our work, a catalytic system efficiently converting glucose to HMF was designed, which is guided by catalytic coupling at multiple length scales. A catalyst from the sulfonated and carbonized glucose with aluminum loading containing Lewis and Brønsted acidic sites, along with tetrahydrofuran/H2O‐NaCl featuring low boiling point and biphasic solvent, was introduced to the catalytic conversion of glucose. Not only the HMF yield of 75% from glucose was achieved at 140°C for 8 h but also the purity of HMF went up to 93% by facile separation and evaporation. In the reuse of the catalysts, the selectivity of HMF was basically maintained at 81% with the conversion of glucose decreasing by ca. 20% after five runs.

Catalytic dehydration of glucose to 5-HMF using heterogeneous solid catalysts in a biphasic continuous-flow tubular reactor

This work aimed to produce 5-hydroxymethylfurfural (5-HMF) from glucose in a biphasic continuous-flow tubular reactor with various heterogeneous solid acid catalysts or combined solid acid-base catalysts. Among the catalysts tested, niobium phosphate (NbP) was found to be the most active catalyst for glucose dehydration with a maximum 5-HMF yield of 45% at 150 °C. The higher activity of NbP was attributed to its higher total number of acid sites and BET surface area, as well as the presence of both Lewis acid and Brønsted acid sites. The effects of different operating conditions such as aqueous to organic (A/O) phase ratio, reaction temperature and feeding flow rate on the activity of some selected catalysts were studied. Reducing A/O ratio by increasing the extracting organic phase flow rate and increasing the reaction temperature (up to 150 °C) were found to positively affect 5-HMF production from glucose in the presence of NbP. Kinetics study demonstrated that the overall reaction of glucose dehydration to 5-HMF over the NbP catalyst is a first-order reaction with the reaction rate constants (k) determined as 0.06, 0.21 and 0.6 min−1 at 110, 130 and 150 °C, respectively, and the apparent activation energy (Ea) calculated to be 77 kJ/mol.

Sulfuric Acid-Catalyzed Dehydratization of Carbohydrates for the Production of Adhesive Precursors.

Carbohydrates and hexose-derived 5-hydroxymethylfurfural (5-HMF) are platform chemicals for the synthesis of sustainable binders. New, greener approaches aim at the development of production systems, which minimize process steps and avoid organic solvents or other auxiliaries that could interfere with subsequent resin synthesis. In our work, carbohydrate solutions rich in 5-hydroxymethylfurfural (5-HMF) were produced using a continuous-flow microreactor and diluted H2SO4 as the catalyst. After optimization of the process conditions (temperature, reaction time, catalyst content), a 5-HMF yield of 49% was obtained at a low reaction time of 0.6 min and a catalyst concentration of 1% at 175 °C and 17 bar pressure. Extensive rehydration of the product was avoided by efficient immediate cooling of the reaction solution. The stability of the reaction system was improved by increasing the inner diameter of the capillary in the flow reactor to 2 mm. Advantageously, the obtained reaction mixtures are used directly as precursors in the development of sustainable binder systems, without the need of additional purification, filtration, or extraction steps.

Microwave mediated enhanced production of 5-hydroxymethylfurfural using choline chloride-based eutectic mixture as sustainable catalyst

The present work is a significant contribution to the production of 5-hydroxymethylfurfural (5-HMF) from carbohydrates-based feedstocks using environmentally benign choline chloride (ChCl)-based deep eutectic solvents (DESs) as catalyst in the presence of an inexpensive acetone/water solvent system. Under microwave irradiations, the acidity of organic acids in DESs can be a key criterion in screening out different eutectic mixtures. Among others, the ChCl: Lactic acid (LA) mixture was found to be the most efficient DES giving a 5-HMF yield of 30.12% on fructose dehydration. Optimization of different reaction parameters resulted in an enhanced 5-HMF yield of 87.2% in 30 min at 140 °C using ChCl: LA DES. The synergistic effect between LA and ChCl is also highlighted in boosting the 5-HMF yield. As compared to conventional oil bath heating, microwave heating resulted in significantly higher 5-HMF yield at a lower reaction time. The catalytic system ChCl: LA showed an appreciable yield of 5-HMF ranging from 83.1 to 71.2% for 5 recycle runs. Overall, we have developed a low cost, easy, energy-effective, green, and sustainable process ensuring high 5-HMF production.

Valorization of microalgae into 5-hydroxymethylfurfural by two-step conversion with ferric sulfate

Microalgae are known as renewable, potential, and sustainable feedstocks for biofuel production. The present work investigated the efficient valorization of green microalgae Chlorella sp. to produce sugars and 5-hydroxymethylfurfural (5-HMF) using thermochemical conversion with a metal-salt (ferric sulfate) as catalyst using a statistical approach and two-step conversion. A statistical approach with a Box–Behnken design was introduced to optimize the conversion for producing sugars. As a result of optimization, 86.46% sugar yield (68.32% glucose yield) was achieved under the condition of 5% biomass and 0.6 g-catalyst/g-biomass at 155 °C and 40 min. Two-step thermochemical conversion was introduced to produce 5-HMF from microalgae. In the first step, sugars were produced from the above optimum condition; in the second step, sugar hydrolysates were converted into 5-HMF by thermochemical conversion without an additional catalyst. In two-step conversion, the maximum 5-HMF yield (37.23%) was achieved at 170 °C and 60 min from the sugar hydrolysate of microalgae obtained from the first-step thermochemical conversion with ferric sulfate. In conclusion, the microalgae as biomass and ferric sulfate as catalyst have availability and the potential to produce biosugars and platform chemicals.