Search

5-Hydroxymethylfurfural (HMF) and furfural, both of which can be derived from renewable sources, are key components for the production of different chemicals and fuels. In this study, rice straw, a cheap, abundant, and mainly unused agricultural waste, is converted to furans by a dilute acid hydrolysis process. The highest yield of HMF in a single-phase hydrolysis was 15.3 g/kg straw, attained at 180°C during 3 h with 0.5% sulfuric acid, while the maximum yield of furfural, 59 g/kg straw, was obtained at 150°C during 5 h. Different extracting solvents, including 2-PrOH, 1-BuOH, methyl isobutyl ketone (MIBK), and acetone at 180°C for 3 h as well as tetrahydrofuran (THF) at 150°C for 5 h were examined in biphasic systems. Use of the solvents generally improved the production of HMF compared to the single aqueous phase process. The best results of HMF production, more than 59 g/kg straw, were obtained in the systems containing either 2-PrOH or 1-BuOH. Using THF as an extracting solvent, a relatively high furfural yield, 118.2 g/kg straw, was obtained, and 96% of furfural produced in this system was extracted into THF during the process., (Copyright © 2010 Elsevier Ltd. All rights reserved.)

We have produced fully biomass-based poly(butylene succinate) (PBS) from furfural produced from inedible agricultural cellulosic waste. Furfural was oxidized to give fumaric acid. Fumaric acid was hydrogenated under high pressure with a palladium-rhenium/carbon catalyst to give 1,4-butanediol, and with a palladium/carbon catalyst to give succinic acid. Dimethyl succinate was synthesized from fumaric acid by esterification and hydrogenation under normal pressure. Fully biomass-based PBS was obtained by polycondensation of biomass-based 1,4-butanediol and biomass-based succinic acid or dimethyl succinate. The biomass carbon ratio calculated from (14)C concentrations measured by accelerator mass spectroscopy (AMS) verified that the PBS obtained in this study contained only biomass carbon. The polycondensation of biomass-based 1,4-butanediol and petroleum-based terephthalic acid or dimethyl terephthalate gave partially biomass-based poly(butylene terephthalate), which is an engineering plastic.

Methanol, acetone and diethyl ether extracts of Alpinia galanga have been evaluated against pathogens viz. Bacillus subtilis MTCC 2391, Enterobacter aerogene, Enterobacter cloacae, Enterococcus faecalis, Escherichia coli MTCC 1563, Klebsiella pneumoniae, Pseudomonas aeruginosa MTCC 6642, Salmonella typhimurium, Staphylococcus aureus and Streptococcus epidermis using Agar well diffusion method. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of all the extracts were determined using the macrodilution method. Methanol extracts have shown excellent activity towards all the pathogens with MIC and MBC values ranging from 0.04-1.28 mg/ml and 0.08-2.56 mg/ml, respectively. The GC-MS analysis of methanol extracts have yielded compounds like 5-hydroxymethyl furfural (59.9%), benzyl alcohol (57.6%), 1,8 cineole (15.65%), methylcinnamate (9.4%), 3-phenyl-2-butanone (8.5%) and 1,2 benzenedicarboxylic acid (8.9%), which could be responsible for its broad spectrum activity. So, A. galanga can be quite resourceful for the development of new generation drugs.

To establish HPLC chromatographic fingerprints to control the quality of Chinese herbal medicine. In this study, fingerprints were established based on HPLC-DAD chromatographs. And with these fingerprints, content variations of three important active components catalpol, 5-hydroxymethylfurfural and acteoside in Rehmannia rhizome were analyzed during processing, as well as changes of the fingerprints. Fingerprints comparing with the standard prepared Rehmannia fingerprints which came from the mean of prepared ones randomly chosen for standard was done to seek optimal processing time. The results indicated that catalpol decreased quickly as braising prolonged and almost vanished in the end. While the active component of 5-HMF increased linearly throughout the process of braising. And the content of acteoside did not show obvious change. Similarity to standard prepared Rehmannia reached summit after braising for 26 hours. So 26 hours could be considered to be the optimum time for braising prepared Rehmannia. Chromatographic fingerprint is convenient for revealing changes of constituents and for accurately controlling quality during processing prepared Rahmannia.

A generic hapten of nitrofurans was synthesized by derivatization of 5-nitrofurfural with diamine, and the hapten was coupled to carrier protein to prepare different immunogens and coating antigens by using diazotization method and glutaraldehyde method. The obtained novel polyclonal antibodies from immunized rabbits showed broad cross reactivity among seven nitrofurans. After assessment of four coating antigen/antibody combinations, an indirect competitive immunoassay was developed to simultaneously detect the seven nitrofurans in animal feeds. The limits of detection for these analytes were in the range of 5-16 μg kg(-1) depending on the compound. Recoveries from nitrofurans fortified blank feeds at levels of 30 and 100 ng g(-1) were in a range of 82.6-108.4% with coefficients of variation lower than 11.4%. The immunoassay was further validated by a HPLC method and the two methods showed good correlation (r=0.9924). Therefore, the proposed immunoassay could be used as a practical method to monitor the illicit use of nitrofurans in animal feeds., (Copyright © 2010 Elsevier B.V. All rights reserved.)

An interaction product of aminotadalafil was isolated from an illegal health food product. The structure of the interaction product was elucidated by means of IR, NMR, and mass spectroscopy. The hitherto unknown compound was characterized as condensation product of aminotadalafil and hydroxymethylfuraldehyde and is probably the result of a drug-excipient incompatibility., (Copyright 2010. Published by Elsevier B.V.)

Acid-promoted, selective production of 5-hydroxymethylfurfural (HMF) under high fructose concentration conditions was achieved in ionic liquids (ILs) at 80 degrees C. A HMF yield up to 97% was obtained in 8min using 1-butyl-3-methylimidazolium chloride ([C(4)mim]Cl) catalyzed with 9mol% hydrochloric acid. More significantly, an HMF yield of 51% was observed when fructose was loaded at a high concentration of 67wt% in [C(4)mim]Cl. Water content below 15.4% in the system had little effect on HMF yield, whereas a higher water content was detrimental to both reaction rate and HMF yield. In situ NMR analysis suggested that the transformation of fructose to HMF was a highly selective reaction that proceeded through the cyclic fructofuranosyl intermediate pathway. This work increased our capacity to produce HMF, and should be valuable to facilitate cost-efficient conversion of biomass into biofuels and bio-based products.

The renewable furan-based platform chemical, 5-hydroxymethylfurfural (HMF), has been efficiently synthesized from d-fructose and sucrose in the presence of a catalytic amount of protic ionic liquids. The 1-methylimidazolium-based and N-methylmorpholinium-based ionic liquids are employed. As a result, 74.8% and 47.5% yields of HMF are obtained from d-fructose and sucrose, respectively, at 90 degrees C for 2h under nitrogen atmosphere when N-methylmorpholinium methyl sulfonate ([NMM](+)[CH(3)SO(3)](-)) is used as the catalyst in an N,N-dimethylformamide-lithium bromide (DMF-LiBr) system. The acidities of ionic liquids are determined by the Hammett method, and the correlation between acidity and catalytic activity is discussed. Moreover, the effects of reaction temperature and time are investigated, and a plausible reaction mechanism for the dehydration of d-fructose is proposed., (Copyright 2010 Elsevier Ltd. All rights reserved.)

The thermochemistry of the conversion of glucose to levulinic acid through fructofuranosyl intermediates is investigated using the high-level ab initio methods G4 and G4MP2. The calculated gas phase reaction enthalpies indicate that the first two steps involving water molecule elimination are highly endothermic, while the other steps, including additional water elimination and rehydration to form levulinic acid, are exothermic. The calculated gas phase free energies indicate that inclusion of entropic effects makes the dehydration steps more favorable, although the elimination of the first water is still endothermic. Elevated temperatures and aqueous reaction environments are also predicted to make the dehydration reaction steps thermodynamically more favorable. On the basis of these enthalpy and free energy calculations, the first dehydration step in conversion of glucose to levulinic acid is likely a key step in controlling the overall progress of the reaction. An assessment of density functional theories and other theoretical methods for the calculation of the dehydration and hydration reactions in the decomposition of glucose is also presented.

Lignocellulosic biomass is considered as the future feedstock for ethanol production because of its low cost and its huge availability. One of the major lignocellulosic materials found in great quantities to be considered, especially in tropical countries, is sugarcane bagasse (SCB). This work deals with its current and potential transformation to sugars and ethanol, considering pretreatment technologies, detoxification methods and biological transformation. Some modeling aspects are exposed briefly. Finally stability is discussed for considering the high nonlinear phenomena such as multiplicity and oscillations, which make more complex the control as a result of the inhibition problems during fermentation when furfural and formic acid from SCB hydrolysis are not absent., (Copyright 2009 Elsevier Ltd. All rights reserved.)

In this work, a recently developed extraction technique for sample preparation aiming the analysis of volatile and semi-volatile compounds named gas-diffusion microextraction (GDME) is applied in the chromatographic analysis of aldehydes in beer. Aldehydes-namely acetaldehyde (AA), methylpropanal (MA) and furfural (FA)-were simultaneously extracted and derivatized with 2,4-dinitrophenylhydrazine (DNPH), then the derivatives were separated and analyzed by high-performance liquid chromatography with spectrophotometric detection (HPLC-UV). The identity of the eluted compounds was confirmed by high-performance liquid chromatography-atmospheric pressure chemical ionization-mass-spectrometry detection in the negative ion mode (HPLC-APCI-MS). The developed methodology showed good repeatability (ca. 5%) and linearity as well as good limits of detection (AA-12.3, FA-1.5 and MA 5.4microgL(-1)) and quantification (AA-41, FA-4.9 and MA 18microgL(-1)); it also appears to be competitive in terms of speed and cost of analysis., (Copyright 2010 Elsevier B.V. All rights reserved.)

Low catalyst loading of a cationic oxorhenium(V) oxazoline complex, [2-(2'-hydroxyphenyl)-2-oxazolinato(-2)]oxorhenium(v), condenses diols and aldehydes to give 1,3-dioxolanes in excellent yields under neat conditions and reasonably mild temperatures. The reaction is applicable to biomass-derived furfural and glycerol. The resulting cyclic acetals may find use as value-added chemicals and/or oxygenate fuel additives. Differences in the stereoselectivity of the reaction for epoxides versus diols provide insight into the reaction mechanism.

The one-pot acid-catalysed conversion of mono/di/polysaccharides (inulin, xylan, cellobiose, sucrose, glucose, fructose, xylose) into 2-furfuraldehyde (FUR) or 5-hydroxymethylfurfural (HMF) in the presence of aluminium-containing mesoporous TUD-1 (denoted as Al-TUD-1, Si/Al = 21), at 170 degrees C was investigated. Xylose gave 60% FUR yield after 6 h reaction; hexose-based mono/disaccharides gave less than 20% HMF yield; polysaccharides gave less than 20 wt % FUR or HMF yields after 6 h. For four consecutive 6 h batches of the xylose reaction in the presence of Al-TUD-1, the FUR yields achieved were similar, without significant changes in Si/Al ratio.

A new pretreatment technology using dilute ammonium hydroxide was evaluated for ethanol production on sorghum. Sorghum fibers, ammonia, and water at a ratio of 1:0.14:8 were heated to 160 degrees C and held for 1 h under 140-160 psi pressure. Approximately, 44% lignin and 35% hemicellulose were removed during the process. Hydrolysis of untreated and dilute ammonia pretreated fibers was carried out at 10% dry solids at an enzyme concentration of 60 FPU Spezyme CP and 64 CBU Novozyme 188/g glucan. Cellulose digestibility was higher (84%) for ammonia pretreated sorghum as compared to untreated sorghum (38%). Fermentations with Saccharomyces cerevisiae D(5)A resulted in 24 g ethanol /100 g dry biomass for dilute ammonia pretreated sorghum and 9 g ethanol /100 g dry biomass for untreated sorghum.

Objective: To study the chemical constituents from Radix Ranunculi Ternate., Methods: The compounds were isolated by silica gel, Sephadex LH-20, and ODS column chromatography, and their structures were elucidated by means of spectral analysis., Results: Eight compounds were isolated and identified as phillygenin (I), bis-(2-ethylhexyl) phthalate (DEHP, II), henicosanoic acid methyl ester (III), 5-hydroxymethyl-furfural (IV), mixture of stigmasterol and sitosterol (V and VI), daucosterol (VII)., Conclusion: Compounds I-III are isolated from the genus for the first time.

Three different ionic liquids, 1-ethyl-3-methylimidazolium tetrafluoroborate, [EMIM][BF(4)]; 1-butyl-3-methylimidazolium trifluoromethanesulfonate, [BMIM][OTf]; and 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide [bmpyrr][NTf(2)] were studied as electrolytes in the electroanalytical quantification of 2-furaldehyde using square wave and differential pulse voltammetries. On applying a cathodic scan, a well-defined 2-electron wave was observed corresponding to the reduction of 2-furaldehyde to furfuryl alcohol. The electrochemical stability of the ionic liquids as electrolytes for analytical aspects and electrokinetic studies was investigated using a glassy carbon electrode (GCE). The measurements were carried out in a designed double-wall three-electrode cell, using two platinum wires as the quasi-reference and counter electrodes. Differential pulse voltammetry was found to be the most sensitive method at GCE. The detection limits of 1.4, 19.0 and 2.5 microg g(-1) were obtained for the determination of 2-furaldehyde in [EMIM][BF(4)], [BMIM][OTf] and [BMPyrr][NTf(2)], respectively. At a concentration of 50 microg g(-1), the maximum relative standard deviation (n=3) was 4.9%. The effect of water content of the ionic liquids on their potential windows and waveforms was also investigated. The proposed method was successfully applied to the determination of 2-furaldehyde in real samples, especially in oil matrices., ((c) 2009 Elsevier B.V. All rights reserved.)

Objective: To study the chemical constituents of Rhizoma of Coniogramme japonica., Methods: The Rhizome of C. japonica were extracted with ethanol and the chemical constituents were separated by chromatography technique, and their structures were determined by spectral analysis., Results: Six compounds were isolated and identified as butyl 2-formyl-5-butoxymethyl-1 H-pyrrole-1-butanoate (1), pterolactam (2), 5-hydroxymethylfurfural (3), methyl linoleate (4), trilinolein (5), dehydrovomifoliol (6)., Conclusion: All compounds are isolated from the genus for the first time, and the compound 1 is a new compound.

The kinetics of 5-hydroxymethylfurfural (HMF) formation in Chinese rice wine was investigated under different treatment conditions. Samples I and II were the rough rice wine and outflow fraction of the rice wine from the macroporous resin, respectively. Sample III was the fraction derived from sample II loaded through ion-exchange resin. The HMF content of the different samples under a range of temperature values from 323.15 to 363.15 K was measured by high-performance liquid chromatography. The results demonstrated that the kinetics of HMF formation in sample I was determined as first-order [C(t) = C(0) exp(kt)], but those for samples II and III were found to be the zero-order reaction [C(t) = C(0) + kt]. For all three samples, the relationships of reaction rates (k) and temperature (T) were computed as follows: k(1) = 2.81 x 10(5) exp(-43.01/RT), k(2) = 2.33 x 10(18) exp(-123.90/RT), and k(3) = 1.79 x 10(13) exp(-89.16/RT). By applying the Arrhenius equation k = k(f) exp(-E(a)/RT), the activation energy was 43.01, 123.90, and 89.16 kJ mol(-1), respectively. On the basis of these kinetics equations, weak polar components such as phenolic groups may be involved in HMF formation.

The dehydration of D-fructose and glucose has been studied with acidic ionic liquids as catalysts. A series of Brønsted-acidic ionic liquids has been synthesized and tested in the dehydration of D-fructose. The results showed that N-methyl-2-pyrrolidonium methyl sulfonate [NMP](+)[CH(3)SO(3)](-) and N-methyl-2-pyrrolidonium hydrogen sulfate [NMP](+)[HSO(4)](-) have high catalytic activity. Highly efficient and selective dehydration of D-fructose to 5-hydroxymethylfurfural (HMF) was achieved in dimethyl sulfoxide (DMSO) under mild conditions. For example, a 72.3 % yield of HMF with 87.2 % selectivity were obtained for 2 h at 90 degrees C in the presence of 7.5 mol % [NMP](+)[CH(3)SO(3)](-). The effects of the reaction temperature, time, and solvent were investigated in detail. The catalyst and solvent can be recycled for the dehydration of D-fructose. The Hammett method was used to determine the acidities of these ionic liquids, which indicated that the acidity and molecular structure have strong effects on the catalytic activity of ionic liquids. Based on the experimental results, a possible reaction mechanism for the dehydration of D-fructose is proposed.

5-Substituted-2-furan methanols 1a-c are subject to enantioselective carbonyl allylation, crotylation and tert-prenylation upon exposure to allyl acetate, alpha-methyl allyl acetate, or 1,1-dimethylallene in the presence of an ortho-cyclometalated iridium catalyst modified by (R)-Cl,MeO-BIPHEP, (R)-C3-TUNEPHOS, and (R)-C3-SEGPHOS, respectively. In the presence of 2-propanol, but under otherwise identical conditions, the corresponding substituted furfurals 2a-c are converted to identical products of allylation, crotylation, and tert-prenylation. Optically enriched products of carbonyl allylation, crotylation, and reverse prenylation 3b, 4b, and 5b were subjected to Achmatowicz rearrangement to furnish the corresponding gamma-hydroxy-beta-pyrones 6a-c, respectively, with negligible erosion of enantiomeric excess.

A convenient and cost-efficient method featuring the integration of enzymatic and acid catalysis has been developed for the selective conversion of glucose into HMF, which provides a new strategy for HMF production from glucose.

Production of 5-hydroxymethylfurfural (HMF) and furfural from lignocellulosic biomass was studied in ionic liquid in the presence of CrCl(3) under microwave irradiation. Corn stalk, rice straw and pine wood treated under typical reaction conditions produced HMF and furfural in yields of 45-52% and 23-31%, respectively, within 3 min. This method should be valuable to facilitate energy-efficient and cost-effective conversion of biomass into biofuels and platform chemicals.

5-Hydroxymethylfurfural (5-HMF) is known as an indicator of quality deterioration in a wide range of foods. 5-HMF is formed as an intermediate in the Maillard reaction and has been identified in a wide variety of heat-processed foods. In recent years, the presence of 5-HMF in foods has raised toxicological concerns: data have shown cytotoxic, genotoxic and tumoral effects but further studies suggest that 5-HMF does not pose a serious health risk. However the subject is still a matter of debate. We investigated the genotoxicity of the food-borne contaminant 5-HMF using the Ames test, the micronucleus (MN) and the single-cell gel electrophoresis (SCGE) assays in the human metabolically active HepG2 cell line. Cytotoxic effect of 5-HMF was first assessed using Alamar Blue as a sensitive sub-lethal assay. 5-HMF did not induce any genic mutation in bacteria whatever the concentration in the Ames test. Furthermore, it does not induce clastogenic or aneugenic effects in the HepG2 cells. In contrast, 5-HMF induced HepG2 DNA damage at concentrations from 7.87 to 25 mM in the comet assay suggesting a weak genotoxic effect of 5-HMF in the HepG2 cells probably repaired., (2009 Elsevier Ireland Ltd. All rights reserved.)

Present communication elicits an interesting interaction between 2H-azirine and a number of electron rich and electron deficient dienes. A series of substituted 2H-azirine 1-10, and three dienes namely cyclopentadiene D-1, furfural D-2, and dinitrofuran D-3 were chosen to investigate and critically review the reactivity and selectivity of Diels-Alder cycloaddition strategy. The global and local electrophilicity patterns have been evaluated to interpret the electrophilic/nucleophilic behavior of dienes D-1 to D-3 and dienophiles 1-10, in polar Diels-Alder cycloaddition, using the DFT method at the B3LYP/6-31G* level of theory. Regional nucleophilicity have been evaluated using local nucleophilicity descriptor N(k) (Perez, P.; Domingo, L. R.; Duque-Norena, M.; Chamorro, E. J. Mol. Struct. THEOCHEM 2009, 895, 86-91), and regional electrophilicity at the active sites of the interactive species involved in Diels-Alder processes have been described on a quantitative basis using local electrophilicity index omega(k).

In this work, mediated amperometry was used to evaluate whether differences in intracellular nicotinamide adenine dinucleotide (phosphate) (NAD(P)H) level could be observed between a genetically modified Saccharomyces cerevisiae strain, engineered for NADPH dependent 5-hydroxymethyl-2-furaldehyde (HMF) reduction, and its control strain. Cells overexpressing the alcohol dehydrogenase 6 gene (ADH6 strain) and cells carrying the corresponding control plasmid (control strain) were each immobilized on Au-microelectrodes. The real-time dynamics of NAD(P)H availability in the two strains, preincubated with HMF, was probed using the menadione-ferricyanide double mediator system. A lower intracellular NADPH level as the consequence of more effective HMF reduction was observed for the ADH6 strain both with and without added glucose, which increases the overall cellular NADPH level. The mediated amperometric signal during real-time monitoring of the concentration dependent HMF reduction in living cells could be translated into the cellular enzyme kinetic parameters: K(M,cell)(app), V(MAX), k(cat,cell), and k(cat,cell)/K)M,cell)(app). The results indicated that the overexpression of the ADH6 gene gave a 68% decrease in K(M,cell)(app) and 42% increase in V(MAX), resulting in a 4-fold increase in k(cat,cell)/K(M,cell)(app). These results demonstrate that the mediated amperometric method is useful for monitoring the short-term dynamics of NAD(P)H variations and determining cellular enzyme kinetic parameters in S. cerevisiae cells.

Untreated and hydrothermally treated sorghum bagasse (SB) was hydrolyzed to simple sugars by the synergistic action of cellulases and hemicellulases produced by the fungi Fusarium oxysporum and Neurospora crassa. Synergism between the two lignocellulolytic systems was maximized with the application of higher fraction of N. crassa enzymes. Hydrothermolysis of SB was studied at a wide range of treatment times and temperatures. At intense pretreatment conditions (210 degrees C for 20 min; logR(0)=4.54), the residual hemicellulose percentage was 17.45%, while formation of inhibitory products, 5-hydromethyl-furfural (HMF), furfural, acetic and formic acid, (0.21, 0.51, 3.36 and 1.80 g/l, respectively) remained in acceptable levels. Maximum conversion of cellulose and total polysaccharides of the untreated SB were 23.18% and 18.79%, respectively. Combining hydrothermal treatment and enzymatic hydrolysis of released oligosaccharides and insoluble solids resulted in improvement of cellulose (approximately 15% increase) and total polysaccharides (two fold) hydrolysis compared to that of untreated SB.

Experiment is performed to investigate the mechanism of the cellulose pyrolysis and the formation of the main products. The evolution of the gaseous products is examined by the 3-D FTIR spectrogram at the heating rate of 5-60 K/min. A pyrolysis unit, composed of fluidized bed reactor, carbon filter, vapour condensing system and gas storage, is employed to investigate the products of the cellulose pyrolysis under different temperatures (430-730 degrees C) and residence time (0.44-1.32 s). The composition in the bio-oil is characterized by GC-MS while the gases sample is analyzed by GC. The effects of temperature and residence time on the main products in bio-oil (LG, 5-HMF, FF, HAA, HA and PA) are examined thoroughly. Furthermore the possible routes for the formation of the products are developed from the direct conversion of cellulose molecules and the secondary reactions of the fragments. It is found that the formation of CO is enhanced with elevated temperature and residence time, while slight change is observed for the yield of CO(2).

Marine red algae of genus Laurencia are becoming the most important resources to produce unique natural metabolites with wide bioactivities. However, reports related to Laurencia undulata, an edible species used as folk herb, are rarely found to date. In this research, 5-hydroxymethyl- 2-furfural (5-HMF) was isolated and characterized by nuclear magnetic resonance (NMR) from Laurencia undulata as well as other marine algae. The following characteristics of 5-HMF were systematically evaluated: its antioxidant activities, such as typical free-radicals scavenging in vitro by electron spin resonance spectrometry (ESR) and intracellular reactive oxygen species (ROS) scavenging; membrane protein oxidation; oxidative enzyme myeloperoxidase (MPO) inhibition; as well as expressions of antioxidative enzymes glutathione (GSH) and superoxide dismutase (SOD) on the gene level, using the polymerase chain reaction (PCR) method. The results demonstrated that 5-HMF could be developed as a novel marine natural antioxidant or potential precursor for practical applications in the food, cosmetic, and pharmaceutical fields.

Pyrolysis-gas chromatography/mass-spectrometry (Py-GC/MS) was employed to achieve fast pyrolysis of cellulose and on-line analysis of the pyrolysis vapors. Three sulfated metal oxides (SO(4)(2-)/TiO(2), SO(4)(2-)/ZrO(2) and SO(4)(2-)/SnO(2)) were prepared and used for catalytic cracking of the pyrolysis vapors. The distribution of the pyrolytic products was significantly altered by the catalysts. Those important primary pyrolytic products, such as levoglucosan and hydroxyacetaldehyde, were significantly decreased or even completely eliminated. Meanwhile, the catalysis increased three light furan compounds (5-methyl furfural, furfural and furan) greatly. In regard to the selectivity of the three catalysts, the SO(4)(2-)/SnO(2) was the most effective catalyst for obtaining 5-methyl furfural, while the SO(4)(2-)/TiO(2) favored the formation of furfural and the SO(4)(2-)/ZrO(2) favored the formation of furan.

In the United States, high-fructose corn syrup (HFCS) has become a sucrose replacement for honey bees and has widespread use as a sweetener in many processed foods and beverages for human consumption. It is utilized by commercial beekeepers as a food for honey bees for several reasons: to promote brood production, after bees have been moved for commercial pollination, and when field-gathered nectar sources are scarce. Hydroxymethylfurfural (HMF) is a heat-formed contaminant and is the most noted toxin to honey bees. Currently, there are no rapid field tests that would alert beekeepers of dangerous levels of HMF in HFCS or honey. In this study, the initial levels and the rates of formation of HMF at four temperatures were evaluated in U.S.-available HFCS samples. Different HFCS brands were analyzed and compared for acidity and metal ions by inductively coupled plasma mass spectroscopy. Levels of HMF in eight HFCS products were evaluated over 35 days, and the data were fit to polynomial and exponential equations, with excellent correlations. The data can be used by beekeepers to predict HMF formation on storage. Caged bee studies were conducted to evaluate the HMF dose-response effect on bee mortality. Finally, commercial bases such as lime, potash, and caustic soda were added to neutralize hydronium ion in HMF samples, and the rates of HMF formation were compared at 45 degrees C.

A 2-furaldehyde-selective PVC-membrane electrode is designed based on the host-guest interaction between tetrabenzyl ether Calix[4]arene, as an ionophore, and a lipophilic hydrazone derivative generated in situ from reaction of 2-furaldehyde and Girard's reagent T. At a pH of 9.2, the electrode exhibits a Nernstian response over the 2-furaldehyde concentration range of (5.0 x 10(-5))-(1.0 x 10(-1)) M. The electrode has found to be chemically inert and of adequate stability with a response time of 15 s with a good reproducibility (+/-0.2 mV) and can be used for a long working lifetime. In order to improve the minimum detectable concentration of 2-furaldehyde, further studies have been performed using a coated graphite electrode and coated platinum and gold disks. Some analytical aspects of adsorptive square wave voltammetry have also been presented in order to elucidate the adduct formation between 2-furaldehyde and Girard's reagent T. The interfering effects of some Na(+), K(+), NH(4)(+), formaldehyde, 5-hydroxymethyl 2-furaldehyde (HMF), excess of Girard's reagent T and organic solvents such as isopropyl alcohol and N,N-dimethylformamide on the sensor's response have been studied. The viability of using the electrode for the trace determination of 2-furaldehyde in several Iranian oil refinery wastewater samples is also demonstrated. The results obtained from the developed method for real samples are compared with those from UV-spectrophotometric and high-performance liquid chromatographic experiments.

Hemoglobin (Hb) adducts are used to measure reactive compounds/metabolites in vivo. Schiff base adducts from aldehydes to N-termini in Hb have been measured by GC-MS/MS after stabilisation through reduction, and detachment by a modified Edman procedure. This paper describes a further development using 5-hydroxymethylfurfural (HMF) and its probable metabolite, 2,5-furandialdehyde (FDA), as model compounds. Reference compounds were synthesized and characterized. The conditions for the reduction of the Schiff bases were optimized using NaBH(3)CN as a mild reducing agent, and steps used in the earlier method could be deleted. The adduct from FDA could not be specifically analysed, as selective reduction of the imine could not be achieved. In a few samples of human blood, background levels of 10-35 pmol/g globin of the HMF adduct were observed. Half-lifes of the reversible Schiff base adduct from HMF were determined to 3.4h at 37 degrees C and 10.9h at 25 degrees C. The developed method showed good sensitivity and reproducibility for the analysis of the Schiff base from HMF, with improvements regarding simplicity of work-up procedures due to mild conditions. The developed method could be explored for application to adducts from other aldehydes bound as Schiff bases to N-termini in Hb.

The aerobic oxidation of 5-hydroxymethylfurfural, a versatile biomass-derived chemical, is examined in water with a titania-supported gold-nanoparticle catalyst at ambient temperature (30 °C). The selectivity of the reaction towards 2,5-furandicarboxylic acid and the intermediate oxidation product 5-hydroxymethyl-2-furancarboxylic acid is found to depend on the amount of added base and the oxygen pressure, suggesting that the reaction proceeds via initial oxidation of the aldehyde moiety followed by oxidation of the hydroxymethyl group of 5-hydroxymethylfurfural. Under optimized reaction conditions, a 71% yield of 2,5-furandicarboxylic acid is obtained at full 5-hydroxymethylfurfural conversion in the presence of excess base., (Copyright © 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The effects of surfactants addition on enzymatic hydrolysis and subsequent fermentation of steam exploded lodgepole pine (SELP) and ethanol pretreated lodgepole pine (EPLP) were investigated in this study. Supplementing Tween 80 during cellulase hydrolysis of SELP resulted in a 32% increase in the cellulose-to-glucose yield. However, little improvement was obtained from hydrolyzing EPLP in the presence of the same amount of surfactant. The positive effect of surfactants on SELP hydrolysis led to an increase in final ethanol yield after the fermentation. It was found that the addition of surfactant led to a substantial increase in the amount of free enzymes in the 48 h hydrolysates derived from both substrates. The effect of surfactant addition on final ethanol yield of simultaneous saccharification and fermentation (SSF) was also investigated by using SELP in the presence of additional furfural and hydroxymethylfurfural (HMF). The results showed that the surfactants slightly increased the conversion rates of furfural and HMF during SSF process by Saccharomyces cerevisiae. The presence of furfural and HMF at the experimental concentrations did not affect the final ethanol concentration either. The strategy of applying surfactants in cellulase recycling to reduce enzyme cost is presented., ((c) 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009.)

Enantioenriched pyranones are important intermediates in the synthesis of natural products and the generation of compound libraries. A one-pot method for their synthesis is outlined. Catalytic asymmetric alkylation of 2-furfurals in the presence of catalytic (-)-MIB generates enantioenriched furyl zinc alkoxides. Addition of water/THF followed by NBS results in formation of pyranones with ee's >90% and yields between 46-77%.

The ethyl 5-(2'-alkoxycarbonyl-substituted phenoxy)furan-2-carboxylates (1C-13C) showed good anti-platelet aggregation,(1)) anti-allergic(2)) and anti-inflammatory activities.(2)) A series of 5-(2'-alkoxycarbonyl-substituted phenoxy)furfurals (1F-13F) were prepared for comparing the above activities. The objectives of this research are the synthesis and structural pattern recognition of compounds 1F-13F. The Silica Gel 60 column chromatography method was employed to separate and purify pure compounds 1F-13F by three solvent systems. For the structure elucidation of compounds 1F-13F, four spectroscopic methods were used: electron impact mass (EI-MS), UV-VIS, IR and NMR spectrometers. With the help of spectrometers, investigations can be performed on spectroscopic data. A simple methodology for recognizing structural patterns was carried out with the aid of statistical analysis designed to establish the classification model of the structural skeleton in this research. It was found that compounds 1C-13C and 1F-13F have similar chemical profiles and are clustered into one group. The pattern plots revealed valuable information and showed good correlation between compounds 1C-13C and 1F-13F. These findings correlate directly with the resulting spectroscopic data. These results with those obtained by EI-MS and NMR patterns give insight into a reliable pattern recognition for determining both 1C-13C and 1F-13F skeletons.

A simple and sensitive method for the determination of 5-hydroxymethylfurfural (HMF) in coffee, honey, beer, Coke, and urine by high-performance liquid chromatography (HPLC) is presented. This method is based on the formation of the 2,4-dinitrophenylhydrazone of HMF and subsequent polymer monolith microextraction (PMME) of this derivative. A poly(methacrylic acid-co-ethylene glycol dimethacrylate) (MAA-co-EGDMA) monolithic capillary column was selected as the extraction medium. Several parameters affecting the derivatization of HMF with 2,4-dinitrophenylhydrazine (DNPH) followed by extraction of the derivative were optimized. The procedure is simple and offers high sensitivity and specificity since the derivative of HMF is well preconcentrated by PMME with poly(MAA-co-EGDMA) monolith and well separated from the other components of the samples under examination. The recoveries in coffee, honey, beer, Coke, and urine samples were in the range of 83.9-110.8% spiked at different levels with HMF. The inter- and intraday precisions were less than 10%. The LOD (S/N = 3) and LOQ (S/N = 10) for HMF were 1.0 ng/mL and 3.4 ng/mL, respectively.

A remarkable example of inverse-temperature-dependent diastereoselectivity was uncovered while investigating the addition of Grignard reagents to a 3-hydroxytetrahydrofurfural. The free hydroxyl group in the tetrahydrofurfural was found to play a key role in these processes, a result corroborated through a series of DFT calculations that also highlighted an entropic preference for the formation of one diastereomer.

An interfering substance that is not 5-hydroxymethylfurfural appears in some apple juices during high-performance liquid chromatography (HPLC) analysis of patulin based on the AOAC 995.10 method. Because this interfering substance could cause the overestimation of patulin in the apple juices, we tried to identify the substance and to develop an improved method of analyzing patulin free from the influence of this substance. We isolated the substance from the apple juice and identified it as adenosine based on its mass spectrometry, proton nuclear magnetic resonance, and photo diode array spectra. Because of the chemical properties of adenosine, changes in the extraction method under acidic conditions and the HPLC conditions (wavelength and analytical column) were effective for avoiding the influence of adenosine and more specifically for analyzing the patulin. The most effective and simple improvement of the official method was the use of column in-point carbon contents greater than 15.5%.

The key tricyclic intermediate 3a, for the total synthesis of the C(20)-nor analogue of salvinorin A, was prepared in seven steps from 3-furaldehyde. Key steps involved a highly regio- and diastereoselective Lewis acid assisted Diels-Alder reaction followed by base-promoted epimerization and a completely stereoselective conjugate reduction.

The inhibitory effects of furfural and acetic acid on the fermentation of xylose and glucose to ethanol in YEPDX medium by a recombinant Saccharomyces cerevisiae strain (LNH-ST 424A) were investigated. Initial furfural concentrations below 5 g/L caused negligible inhibition to glucose and xylose consumption rates in batch fermentations with high inoculum (4.5-6.0 g/L). At higher initial furfural concentrations (10-15 g/L) the inhibition became significant with xylose consumption rates especially affected. Interactive inhibition between acetic acid and pH were observed and quantified, and the results suggested the importance of conditioning the pH of hydrolysates for optimal fermentation performance. Poplar biomass pretreated by various CAFI processes (dilute acid, AFEX, ARP, SO(2)-catalyzed steam explosion, and controlled-pH) under respective optimal conditions was enzymatically hydrolyzed, and the mixed sugar streams in the hydrolysates were fermented. The 5-hydroxymethyl furfural (HMF) and furfural concentrations were low in all hydrolysates and did not pose negative effects on fermentation. Maximum ethanol productivity showed that 0-6.2 g/L initial acetic acid does not substantially affect the ethanol fermentation with proper pH adjustment, confirming the results from rich media fermentations with reagent grade sugars., ((c) 2009 American Institute of Chemical Engineers Biotechnol.)

Lignocellulosic biomass is a plentiful and renewable resource for fuels and chemicals. Despite this potential, nearly all renewable fuels and chemicals are now produced from edible resources, such as starch, sugars, and oils; the challenges imposed by notoriously recalcitrant and heterogeneous lignocellulosic feedstocks have made their production from nonfood biomass inefficient and uneconomical. Here, we report that N,N-dimethylacetamide (DMA) containing lithium chloride (LiCl) is a privileged solvent that enables the synthesis of the renewable platform chemical 5-hydroxymethylfurfural (HMF) in a single step and unprecedented yield from untreated lignocellulosic biomass, as well as from purified cellulose, glucose, and fructose. The conversion of cellulose into HMF is unabated by the presence of other biomass components, such as lignin and protein. Mechanistic analyses reveal that loosely ion-paired halide ions in DMA-LiCl are critical for the remarkable rapidity (1-5 h) and yield (up to 92%) of this low-temperature (

Objective: To study the chemical constituents of involatile moiety of Pogostemon cablin., Method: Compounds were isolated and purified by repeated column chromatography, and their structures were elucidated by spectroscopic analysis., Result: Nine compounds have been isolated and identified: epifriedelinol (1), 5-hydroxymethol-2-furfural (2), succinic acid (3), beta-sitosterol (4), daucosterol (5), crenatoside (6), 3'''-O-methylcrenatoside (7), isocrenatoside (8), and apigenin-7-O-beta-D-(6"-p-coumaryl)-glucoside (9)., Conclusion: Compounds 2, 3, 6-8 were isolated from Pogostemon genus for the first time.

5-hydroxymethyl-2-furfural is selectively converted into 2,5-furandicarboxylic acid (99 mol % yield) in water, under mild conditions (65-130 degrees C, 10 bar air) with gold nanoparticles supported on nanoparticulate ceria (Au-CeO(2)) and on titania (Au-TiO(2)); the former being more active and selective. A reaction mechanism is established and the rate-limiting step of the reaction is the alcohol oxidation of 5-hydroxymethyl-2-furancarboxylic acid into 2,5-furandicarboxylic acid. The effects of pressure, temperature, substrate-to-catalyst ratio, and amount of base are studied to find the most suitable reaction conditions. The absence of metal leaching is verified by chemical analysis of the reaction solution and by confirming that the reaction does not occur after catalyst removal by filtration in hot water. Substrate degradation is strongly diminished and the catalyst life increased by performing the reaction in two temperature steps.

Three alternative synthetic routes for the synthesis of naturally occurring n-butyl (5-formylfuran-2-yl)methyl succinate (1) are described. One of them started from furfuryl alcohol (4), and the other two synthetic strategies started from 5-(hydroxymethyl)furfural (6), which could be readily obtained from D-fructose. One of the latter involved a two-step reaction sequence: esterification of 6 with succinic anhydride (5) and esterification of the resultant mono-succinate 2 with n-butyl bromide, to give 1 in 85% overall yield. The second, a one-pot two-step synthesis, consisted of treating 6 with 5 followed by the addition of n-butyl bromide to afford the desired natural product 1 in 85% yield.