Furan Products Research Articles

Catalytic Pyrolysis of Waste Achyranthes Root Over Al-MCM-41.

This study examined the thermal and catalytic pyrolysis of waste Achyranthes Root (AR) using pyrolyzer-gas chromatography/mass spectrometry (Py-GC/MS). The non-catalytic pyrolysis of waste AR produced various kinds of oxygenates, such as acetic acid, hydroxy propanone, furfural, phenol, cresol, guaiacols, syringols, and so on. By applying nanoporous Al-MCM-41 with acidic properties and mesopores to the pyrolysis of waste AR, the levels of furan and aromatic hydrocarbons production increased with a concomitant decrease in the other oxygenates. The formation efficiency of furans was improved further by increasing the amount of Al-MCM-41 applied to the catalytic pyrolysis of waste AR.

On the Role of Protonic Acid Sites in Cu Loaded FAU31 Zeolite as a Catalyst for the Catalytic Transformation of Furfural to Furan.

The aim of the present paper is to study the speciation and the role of different active site types (copper species and Brønsted acid sites) in the direct synthesis of furan from furfural catalyzed by copper-exchanged FAU31 zeolite. Four series of samples were prepared by using different conditions of post-synthesis treatment, which exhibit none, one or two types of active sites. The catalysts were characterized by XRD, low-temperature sorption of nitrogen, SEM, H2-TPR, NMR and by means of IR spectroscopy with ammonia and CO sorption as probe molecules to assess the types of active sites. All catalyst underwent catalytic tests. The performed experiments allowed to propose the relation between the kind of active centers (Cu or Brønsted acid sites) and the type of detected products (2-metylfuran and furan) obtained in the studied reaction. It was found that the production of 2-methylfuran (in trace amounts) is determined by the presence of the redox-type centers, while the protonic acid sites are mainly responsible for the furan production and catalytic activity in the whole temperature range. All studied catalysts revealed very high susceptibility to coking due to polymerization of furfural.

Pyrolysis of sugarcane bagasse for bio-chemicals production catalyzed by micro-mesoporous composite molecular sieves

The main objective of this work was to investigate the effects of metal modified micro-mesoporous composite molecular sieves ZSM-5/Al-SBA-15 on the production of valuable chemicals from the pyrolysis of sugarcane bagasse. Metal (Cu, Mg, Ga, Ni, Pd, Ce, Co, Zn) modified ZSM-5/Al-SBA-15 catalysts were prepared by two-step crystallization method and characterized by N2 adsorption–desorption, X-ray diffraction and temperature-programmed desorption of ammonia. The product distribution and composition of liquid product were also analyzed. Results showed that Ni-ZSM-5/Al-SBA-15 catalysts yielded a higher amount of liquid. The chemical compounds of liquid products contained furans, aliphatics, organic acids, phenols, aromatics and esters. Among the Me-ZSM-5/Al-SBA-15 catalysts, Ce-ZSM-5/Al-SBA-15 promoted the production of furans. The production of the main furans was 44.04 area%. Meanwhile, Pd-ZSM-5/Al-SBA-15 had the advantage of improving phenols production, followed by Ce-ZSM-5/Al-SBA-15. The productions of main phenols were 45.13 area% and 41.69 area% obtained with Pd-ZSM-5/Al-SBA-15 and Ce-ZSM-5/Al-SBA-15, respectively. Furthermore, Ce-ZSM-5/Al-SBA-15 exhibited high selectivity for light phenols. The introduction of metal for ZSM-5/Al-SBA-15 had a positive effect on enhancing valuable chemical products, such as furans and phenols.

Techno-Economic Assessment of Mixed-Furan Production from Diverse Biomass Hydrolysates

We present techno-economic analyses of high-yield production of furans [5-hydroxymethylfurfural (HMF) and furfural] from mixed-sugar hydrolysates via a novel hybrid enzyme-chemo-catalytic process. In this process, glucose and xylose in biomass hydrolysates are first isomerized to corresponding ketoses (i.e., fructose and xylulose) using immobilized glucose–xylose isomerase. This enzymatic step is closely integrated with selective extraction of the keto-sugars into a water–immiscible octanol phase containing aryl boronic acids that have a selective affinity for keto-sugars. As a result, isomerization and extraction occur simultaneously and drive the isomerization equilibrium toward the formation of the ketose isomers—a process termed simultaneous isomerization and reactive extraction (SIRE). Then, the keto-sugars in the octanol phase are back-extracted into an acidic ionic liquid (IL) that is uniquely suited for sugar dehydration reactions—a process step termed back extraction (BE). Thereafter, the ketose-rich sugar mixture undergoes dehydration to furans in the IL, which is part of a biphasic reaction medium with tetrahydrofuran (THF) that facilitates extraction and stabilization of the furans as they are formed. Finally, the furans are recovered from THF. Overall, the SIRE–BE–dehydration process provides a pathway for high-yield conversion of lignocellulosic mixed-sugar hydrolysates to HMF and furfural. We performed the chemical process design for a furan production facility operating at a feed rate of 1000 MT/day of biomass hydrolysate sugars (dry basis) via the SIRE–BE–dehydration pathway. The process design corresponded closely with experiments and included integration of novel and energy-efficient product and chemical recovery methods. We estimated the minimum furan selling price (MFSP) to be $1.42/kg—a promising price point for industrially important chemical products. Sensitivity analyses identified feedstock sugar cost and overall furan yield as the dominant contributors to the selling price, and modest improvements of 10% in both parameters could reduce the MFSP to $1.23/kg, a price which is competitive for fuel and polymer precursor applications.

Ti(OiPr)4-Facilitated Formal Deoxygenative Annulation of Alkynyl 1,2-Diketones for the Synthesis of Highly Functionalized Furans.

A unique deoxygenative cyclodimerization of alkynyl 1,2-diketones facilitated by Ti(OiPr)4 is achieved, affording a series of highly functionalized furan products. An unusual C-C bond and C═O bond cleavage of the substrates is observed, and Ti(OiPr)4 plays triplicate roles in the reaction. Furthermore, the products show uncommon fluorescent emission in the solid state, indicating the potential practical applications of this work.

Mechanistic Studies on the Photooxidation of 5‐Hydroxymethylfurfural by Polyoxometalate Catalysts and Atmospheric Oxygen

AbstractEfficient oxidation of 5‐hydroxymethylfurfural (HMF) to corresponding furanic products represents an important research focus of biomass valorization, recent research on polyoxometalates (POMs)‐catalyzed aerobic oxidation of HMF usually requires high temperature and sometimes high O2/air pressure. In this work, we report a mild and green approach to photocatalytically transform HMF into various furanic products using atmospheric oxygen as oxidant and POMs as photocatalysts. The influence of different POMs, light sources, and additives were systematically investigated by various experimental and spectroscopic results. Under minimally optimized conditions, 88.0 % HMF can be efficiently photooxidized with as high as 70.2 % furanic yield by TBA‐W10 catalyst after 2 h irradiation of 365 nm UV light when coupling with TEMPO and Na2CO3 as additives. Finally, detailed mechanistic pathways of HMF photooxidation have been proposed to illustrate the transformation of HMF to various furanic products. This work provides some insightful guidelines for photooxidation of biomass‐derived platform chemicals to value‐added products under efficient, mild, and green conditions, exhibiting potential practical applications in the future.

Rhodium(iii)-catalyzed synthesis of trisubstituted furans via vinylic C-H bond activation.

We report an Rh(iii)-catalyzed one-pot synthesis of trisubstituted furan derivatives through Cvinyl-H activation of α,β-unsaturated ketones with acrylates. The control study revealed that the Heck-type product obtained undergoes Paal-Knorr type cyclization in the presence of an Ag salt. Hence, the Ag salt plays a dual role of a halide scavenger and a Lewis acid catalyst for Paal-Knorr type cyclization. The furan product can be transferred into the respective alcohol and acid derivatives which are useful intermediates in synthesizing biologically active molecules.

High-performance and stable Ru-Pd nanosphere catalyst supported on two-dimensional boron nitride nanosheets for the hydrogenation of furfural via water-mediated protonation

Bimetallic Ru-Pd catalysts are increasingly being investigated for applications in the upgrading of bio-oils to biofuels, owing to their high catalytic activities. Similarly, the recent development of Ru-Pd alloyed nanoparticle (NP) incorporated into hexagonal boron nitride (h-BN) catalysts that can be utilized for tuning the selectivity of desired products has also received considerable attention. In the present study, nanoclusters of Ru0-Pd0 that self-assemble into spherical-like Ru-Pd bimetallic catalytic sites were successfully grown on the surfaces of BN nanosheets (Ru-Pd/BN NCs) via microwave irradiation for 30 s. HR-TEM investigations revealed the formation of 25 nm sized Ru-Pd nanoparticles comprising ≤ 2 nm hexagonal closed-pack (hcp) Ru-Pd clusters with Ru crystallites on the BN nanosheets. Further, furfural was effectively converted into furfural alcohol at a lower temperature (150 °C) and valuable cyclopentanone was obtained at a higher temperature (>250 °C) over the Ru-Pd/BN catalyst through the protonation of water molecules. Furthermore, various solvents namely 2-propanol, toluene, and cyclohexane were also used to achieve the production of furan and tetrahydrofuran over the Ru-Pd/BN catalyst via the decarbonylation of furfural under mild reaction conditions. Moreover, for real-time upgrading, furfural-rich bio-oil produced by the pyrolysis of date-tree biomass was processed over the Ru-Pd/BN catalyst to obtain a maximum of 97% furfural conversion with a 71% FFA yield at 150 °C. The stability and reusability of the catalyst were also determined. The results demonstrated that the Ru-Pd/BN catalyst is highly active and chemically stable, and is therefore suitable for industrial applications.

Conversion of Unprotected Aldose Sugars to Polyhydroxyalkyl and C-Glycosyl Furans via Zirconium Catalysis.

An efficient, zirconium-catalyzed conversion of unprotected aldose sugars with acetylacetone to polyhydroxyalkyl furans or C-glycosylfurans is reported. The furan products are formed in up to 93% yield using 5-10 mol % ZrCl4. Pentoses are readily converted at room temperature, while hexoses and their oligosaccharides require mild heating (i.e., 50 °C). Efficient conversions of glycolaldehyde, glyceraldehyde, erythrose, a heptose, and glucosamine are also demonstrated. This approach outpaces each of the previous Lewis acid-catalyzed methods in at least one the following ways: (i) lower catalyst loadings; (ii) reduced reaction temperatures; (iii) shorter reaction times; (iv) equimolar substrate stoichiometry; (v) expanded sugar scope; (vi) higher selectivities; and (vii) the use of an Earth-abundant Zr catalyst.

Turnover Rate of Metal-Catalyzed Hydroconversion of 2,5-Dimethylfuran: Gas-Phase Versus Liquid-Phase

Hydroconversion (hydrogenation and hydrogenolysis) of biomass-derived furanic compounds giving furan ring-hydrogenation and ring-cleavage products attracts interest for sustainable production of chemicals and fuels. Here, the hydroconversion of 2,5-dimethylfuran (DMF), chosen as a model furanic compound, was investigated at a gas-solid interface over carbon-supported Pt, Pd, Rh and Ru metal catalysts in a fixed-bed reactor at 70–90 °C and ambient pressure. Pt/C was mainly active in ring cleavage of DMF to produce 2-hexanone as the primary product, followed by its hydrogenation to 2-hexanol and hexane. In contrast, Pd/C, Rh/C and Ru/C selectively hydrogenated the furan ring to 2,5-dimethyltetrahydrofuran (DMTHF). The turnover frequency (TOF) of metal sites in the gas-phase DMF hydroconversion was determined from zero-order kinetics in the absence of diffusion limitations. The TOF values decreased in the sequence Pt > Rh > Pd >> Ru, similar to the liquid-phase reaction. The TOF values for the gas-phase reaction were found to be one order of magnitude greater than those for the liquid-phase reaction. This indicates that the gas-phase process is potentially more efficient than the liquid-phase process. TOF values for hydroconversion of ring-saturated furan derivatives, tetrahydrofuran and DMTHF, on Pt/C, were much lower than those for DMF.

Efficient ex-situ catalytic upgrading of biomass pyrolysis vapors to produce methylfurans and phenol over bio-based activated carbon

Analytical pyrolysis-comprehensive two-dimensional gas chromatography/mass spectrometry (Py-GC × GC/MS) was used for the on-line analysis of pyrolysis vapors. Bio-based activated carbon (B-AC) catalysts were used to produce highly selectivity valuable chemicals such as furans and phenols. B-AC catalyst was subjected to several characterizations to investigate the physicochemical properties of the catalyst and its relationship with products distribution. The results showed that B-AC catalyst showed high catalytic activity and selectivity for the production of furans and phenols under mild catalytic temperature (350 °C). Furans are mainly from pyrolysis of cellulose and hemicellulose, while phenols are mainly from pyrolysis of lignin. Methylfurans and phenol were dominated compounds. With the use of B-AC, the relative peak area of methylfurans increased from 6.58% to 39.35% (cellulose), 0%–27.79% (xylan), 0.54%–26.82% (corncob); the relative peak area of phenol increased from 6.31% to 53.83% (lignin) and 2.77%–12.34% (corncob). A significant reduction of aldehydes, ketones, and sugars was also observed over B-AC catalyst. The higher total acidity (weak acidity and Lewis acidity) of B-AC favored the formation of 2-methylfuran and phenol.

Effective selectivity conversion of glucose to furan chemicals in the aqueous deep eutectic solvent

This work demonstrated a smart route of biomass-derived glucose conversion in a biphasic aqueous deep eutectic solvent (DES), which was formed by glucose, ChCl, water, and co-solvent EtAc. Four kinds of value-added furan chemicals, including 5-Hydroxymethylfurfural (HMF), 5-(Acetyloxy) methyl furfural (AMF), 5-Chloromethylfurfural (CMF) and 5-Ethoxymethylfurfural (EMF) were successfully synthesized through a single-step reaction by monitoring the reaction conditions. High yield to 73.2% furan products, including 52.9% of HMF and 17.5% of AMF was obtained from a high concentration of glucose under mild conditions. Moreover, the produced furan mixture could further be converted into other useful chemicals, 2,5-furan dicarboxylic acid (FDCA) and 2,5-dimethyl furan (DMF), directly through simple oxidation and hydrogenation methods, respectively. This study suggested a sustainable synthetic pathway from abundant biomass glucose to furan products and value-added chemicals in the presence of completely green material and catalysts, which showed advantages for the industrial application.

Isolation, identification, and characterization of potential impurities of doramectin and evaluation of their insecticidal activity

Seven impurities were detected in doramectin bulk drug by HPLC analysis. These impurities were named as Imp-I, Imp-II, Imp-III, Imp-IV, Imp-V, Imp-VI, and Imp-VII. All impurities were isolated from doramectin bulk drug by means of preparative HPLC. Among impurities, Imp-IV and Imp-V were unknown and have not been reported previously. Based on the complete spectral analysis, including 1D (1H, 13C, H-D, DEPT 90 and 135), 2D (COSY, HSQC, HMBC, and NOESY) NMR, IR, and ESI-HRMS, the structure of Imp-IV and Imp-V were elucidated. Imp-IV was found to be a furan ring-opening product, while Imp-V lacked a methyl group at the C-14 in doramectin. Identification, isolation, structural characterization, probable formation mechanism, and insecticidal activity of impurities of doramectin were also discussed.

Synthesis, In Vitro Antitumor Activity and Molecular Mechanism of Novel Furan Derivatives and their Precursors.

Compounds featuring furan nucleus exhibit diverse biological properties. Lots of furan derivatives have been explored as pharmaceutical compounds. Hence it is of great interest to explore furan derivatives and their precursors as antitumor agents. A series of novel furan derivatives and their precursors (1-36) were synthesized from α-haloketones and β-dicarbonyl compounds. The reactions between β-dicarbonyl compounds and α-haloketones under basic conditions produced tricarbonyls or dihydrofurans, which were then condensed into their corresponding furan products. Their potential antiproliferative activity in vitro against two human tumor cell lines-cervical (HeLa) and colorectal (SW620) was evaluated using CCK-8 assay. Compounds 1 and 24 were selected for Western blot analysis. Pronounced anti-proliferative effect in the micromolar level was observed for compounds (1, 4, 17, 20, 21, 24, 27, 31 and 32) in HeLa cells, with their IC50 values ranging from 0.08 to 8.79μM. Additionally, furan compounds (24, 26, 32 and 35) had moderate to potent anti-proliferative activity against the SW620 cell line. Furthermore, the possible targets of these compounds were explored by Western blot analysis. The results indicated that the candidates (compounds 1 and 24) exhibited excellent antiproliferative activity, which may be mediated by promoting the activity of PTEN to suppress PI3K/Akt and Wnt/β-catenin signaling. Most of the furan derivatives and their precursors reported herein exhibited moderate to excellent anti-proliferative activity against HeLa cell line and/or SW620 cell line. Compounds 1 and 24, as well as their analogues may be developed as promising anti-cancer agents.

Synthesis of furfural from Acacia mangium wood sawdust‐derived xylose by continuous distillation method using sulfonated carbonaceous catalyst from the same source

AbstractIn this study, the hydrolysate containing ~15 g/L of xylose, which was obtained from Acacia mangium wood sawdust was used for the synthesis of xylose by a continuous distillation method. The synthesis was conducted at 150 °C for 7 h using a carbon‐based sulfonated catalyst (CBSC) from the same biomass source with an acid density of about 4.0 mmol/g. The CBSC showed its efficient catalytic activity in the dehydration of xylose to furfural. Under the optimal catalyst dosage of 20 wt% over xylose, the yield of furfural was 20.4 mol% and 34 wt% of xylose was transformed to furfural. The results presented a successful utilization of a wood‐derived solid acid catalyst for production of furfural from the same biomass source as a sustainable production of furans for biofuel additives.

Selective conversion of lignocellulosic biomass into furan compounds using bimetal-modified bio-based activated carbon: Analytical Py-GC×GC/MS

Bio-based activated carbon supported Cu, Al, Sn and their bimetals were devised to serve as solid acid catalysts for the pyrolysis of xylan to generate furan compounds, and their catalytic activity was evaluated by Py-GC × GC/MS. The Cu–Al/C catalysts with diverse Cu to Al ratios exhibited better performance in enhancing the content of furans and the selectivity of 2-MF compared with other catalysts. Among the series of Cu–Al/C catalysts, 4Cu–2Al/C achieved a content of furan compounds as high as 80.6%, and 2-MF, FF and furan were the major furan products with selectivity values of 44.0%, 30.0% and 15.8%, respectively. Furthermore, the catalyst also worked well in promoting the pyrolysis of xylose, glucose, cellulose and pine to produce furans, and the highest and lowest contents of furans were obtained from glucose (87.8%) and pine (70.1%), respectively. These results suggest the 4Cu–2Al/C obviously promotes the formation of furans, which is comparable to those of recently reported solid acid catalysts. Characterization with XRD, XPS, NH3-TPD, N2 adsorption-desorption, and SEM, demonstrated that the effective interactions between Cu species and Al species facilitated the dehydration of saccharides and the dehydrogenation of cyclopentanones to increase furan compounds. Al species, mainly Al2O3 were the major contributor to the Lewis acid sites, and Cu specie played an essential role in regulating the acidity and enhancing the selectivity of 2-MF. In addition to furans, 4Cu–2Al/C was found to have positive effects on hindering the formation of acids in the pyrolysis products.

Catalytic effects of ammonium dihydrogen phosphate on the pyrolysis of lignocellulosic biomass: Selective production of furfural and levoglucosenone

The catalytic effects of ammonium dihydrogen phosphate (ADP) on the biomass pyrolysis and its mechanism for the selective production of furfural (FF) and levoglucosenone (LGO) were investigated in this study. Samples were prepared with rice husk and ADP solutions with gradient-concentration and pyrolyzed via TG-FTIR and Py-GC/MS. Results showed that ADP made the decomposition of cellulose occur at a lower temperature and greatly enhanced the release of CO groups and carbohydrates below 300 °C, indicating the breakage of glycosidic bond and dehydration reaction during pyrolysis were promoted by ADP. In the pyrolysis volatiles, the production of anhydrosugars and furans was promoted significantly. Due to the rearrangement of the methoxy group, the production of methoxy phenols and CH4 was decreased simultaneously. ADP showed good selectivity for both FF and LGO. With the increased ADP dose, the yield and relative content of FF and LGO increased firstly and then kept stable. 400 °C was found the optimal temperature for the production of FF and LGO, where the sum of the relative peak area of LGO and FF could reach 52.23%. Finally, a possible formation pathway of LGO and FF under the catalysis of ADP was speculated.

Novel Routes in Transformation of Lignocellulosic Biomass to Furan Platform Chemicals: From Pretreatment to Enzyme Catalysis

The constant depletion of fossil fuels along with the increasing need for novel materials, necessitate the development of alternative routes for polymer synthesis. Lignocellulosic biomass, the most abundant carbon source on the planet, can serve as a renewable starting material for the design of environmentally-friendly processes for the synthesis of polyesters, polyamides and other polymers with significant value. The present review provides an overview of the main processes that have been reported throughout the literature for the production of bio-based monomers from lignocellulose, focusing on physicochemical procedures and biocatalysis. An extensive description of all different stages for the production of furans is presented, starting from physicochemical pretreatment of biomass and biocatalytic decomposition to monomeric sugars, coupled with isomerization by enzymes prior to chemical dehydration by acid Lewis catalysts. A summary of all biotransformations of furans carried out by enzymes is also described, focusing on galactose, glyoxal and aryl-alcohol oxidases, monooxygenases and transaminases for the production of oxidized derivatives and amines. The increased interest in these products in polymer chemistry can lead to a redirection of biomass valorization from second generation biofuels to chemical synthesis, by creating novel pathways to produce bio-based polymers.

Catalytic pyrolysis of cellulose over solid acidic catalysts: an environment-friendly method for furan production

The production of high-valuable chemicals, such as furans, from biomass is a hot topic in the past decade. It used to be abstracted from fossil resources. This paper presents a study on the production of furan compounds via catalytic pyrolysis of cellulose on a two-staged fixed-bed reactor. Four solid acidic catalysts including Nb2O5, γ-Al2O3, ZSM-5, and TS-1, were used for the catalytic cracking. The selectivity of furans is 9.6% in a blank test and increased to 43.9% and 20.7% over TS-1 and Nb2O5, respectively. Nevertheless, ZSM-5 and γ-Al2O3 lowered the furan selectivity to 6.8% and 8.8%, respectively. The relationship between the physicochemical properties of different catalysts and their catalytic selectivity towards furan compounds were discussed based on characterization results of N2 physisorption, XRD, NH3-TPD, Py-IR, and TG/DTG.

Effect of roasting conditions on the formation and kinetics of furan in various nuts.

In this study, the effect of roasting on the formation of furan in nuts was investigated. Nut samples were roasted at 150-200°C for 5-25min. As the roasting temperature and roasting time increased, the levels of furan in the nuts increased up to 348ng/g. The concentration of furan was 2.76-224, 0.71-69.0, 1.46-348, 2.68-87.0, and 3.70-94.4ng/g in almonds, peanuts, cashew nuts, hazelnuts, and sacha inchi, respectively. In kinetics analysis, the chemical reaction responsible for the production of furan in nuts followed the zero-order kinetic model, with reaction constants of 3.26×10-9 to 16.5×10-9mol/L.h at 200°C. The apparent activation energy (Ea) was 125.0, 93.6, 86.5, 62.0, and 70.1kJ/mol for almonds, peanuts, cashew nuts, hazelnuts, and sacha inchi, respectively. These results can be used to predict or to calculate furan formation in roasted nuts.