Formation and reduction of furan in a soy sauce model system.

PubMed

Kim, Min Yeop; Her, Jae-Young; Kim, Mina K; Lee, Kwang-Geun

2015-12-15

The formation and reduction of furan using a soy sauce model system were investigated in the present study. The concentration of furan fermented up to 30 days increased by 211% after sterilization compared to without sterilization. Regarding fermentation temperature, furan level after 30 days' fermentation was the highest at 30°C (86.21 ng/mL). The furan levels in the soy sauce fermentation at 20°C and 40°C were reduced by 45% and 88%, respectively compared to 30°C fermentation. Five metal ions (iron sulfate, zinc sulfate, manganese sulfate, magnesium sulfate, and calcium sulfate), sodium sulfite, ascorbic acid, dibutyl hydroxyl toluene (BHT), and butylated hydroxyanisole (BHA) were added in a soy sauce model system. The addition of metal ions such as magnesium sulfate and calcium sulfate reduced the furan concentration significantly by 36-90% and 27-91%, respectively in comparison to furan level in the control sample (p<0.05). Iron sulfate and ascorbic acid increased the furan level at 30 days' fermentation in the soy sauce model system by 278% and 87%, respectively. In the case of the BHT and BHA, furan formation generally was reduced in the soy sauce model system by 84%, 56%, respectively. Copyright © 2015 Elsevier Ltd. All rights reserved.

Trapping of cis-2-butene-1,4-dial to measure furan metabolism in human liver microsomes by cytochrome P450 enzymes.

PubMed

Gates, Leah A; Lu, Ding; Peterson, Lisa A

2012-03-01

Furan is a liver toxicant and carcinogen in rodents. It is classified as a possible human carcinogen, but the human health effects of furan exposure remain unknown. The oxidation of furan by cytochrome P450 (P450) enzymes is necessary for furan toxicity. The product of this reaction is the reactive α,β-unsaturated dialdehyde, cis-2-butene-1,4-dial (BDA). To determine whether human liver microsomes metabolize furan to BDA, a liquid chromatography/tandem mass spectrometry method was developed to detect and quantify BDA by trapping this reactive metabolite with N-acetyl-l-cysteine (NAC) and N-acetyl-l-lysine (NAL). Reaction of NAC and NAL with BDA generates N-acetyl-S-[1-(5-acetylamino-5-carboxypentyl)-1H-pyrrol-3-yl]-l-cysteine (NAC-BDA-NAL). Formation of NAC-BDA-NAL was quantified in 21 different human liver microsomal preparations. The levels of metabolism were comparable to that observed in F-344 rat and B6C3F1 mouse liver microsomes, two species known to be sensitive to furan-induced toxicity. Studies with recombinant human liver P450s indicated that CYP2E1 is the most active human liver furan oxidase. The activity of CYP2E1 as measured by p-nitrophenol hydroxylase activity was correlated to the extent of NAC-BDA-NAL formation in human liver microsomes. The formation of NAC-BDA-NAL was blocked by CYP2E1 inhibitors but not other P450 inhibitors. These results suggest that humans are capable of oxidizing furan to its toxic metabolite, BDA, at rates comparable to those of species sensitive to furan exposure. Therefore, humans may be susceptible to furan's toxic effects.

Trapping of cis-2-Butene-1,4-dial to Measure Furan Metabolism in Human Liver Microsomes by Cytochrome P450 Enzymes

PubMed Central

Gates, Leah A.; Lu, Ding

2012-01-01

Furan is a liver toxicant and carcinogen in rodents. It is classified as a possible human carcinogen, but the human health effects of furan exposure remain unknown. The oxidation of furan by cytochrome P450 (P450) enzymes is necessary for furan toxicity. The product of this reaction is the reactive α,β-unsaturated dialdehyde, cis-2-butene-1,4-dial (BDA). To determine whether human liver microsomes metabolize furan to BDA, a liquid chromatography/tandem mass spectrometry method was developed to detect and quantify BDA by trapping this reactive metabolite with N-acetyl-l-cysteine (NAC) and N-acetyl-l-lysine (NAL). Reaction of NAC and NAL with BDA generates N-acetyl-S-[1-(5-acetylamino-5-carboxypentyl)-1H-pyrrol-3-yl]-l-cysteine (NAC-BDA-NAL). Formation of NAC-BDA-NAL was quantified in 21 different human liver microsomal preparations. The levels of metabolism were comparable to that observed in F-344 rat and B6C3F1 mouse liver microsomes, two species known to be sensitive to furan-induced toxicity. Studies with recombinant human liver P450s indicated that CYP2E1 is the most active human liver furan oxidase. The activity of CYP2E1 as measured by p-nitrophenol hydroxylase activity was correlated to the extent of NAC-BDA-NAL formation in human liver microsomes. The formation of NAC-BDA-NAL was blocked by CYP2E1 inhibitors but not other P450 inhibitors. These results suggest that humans are capable of oxidizing furan to its toxic metabolite, BDA, at rates comparable to those of species sensitive to furan exposure. Therefore, humans may be susceptible to furan's toxic effects. PMID:22187484

Furan in roasted, ground and brewed coffee

PubMed

Gruczyńska, Eliza; Kowalska, Dorota; Kozłowska, Mariola; Majewska, Ewa; Tarnowska, Katarzyna

2018-01-01

Coffee is the most popular hot beverage in the world. The annual coffee production in 2010, 2014 and 2016 was 8.1, 9.0 and 9.3 million tons respectively. There are more than 100 coffee species, but only two of them: Arabica (Coffea arabica) and Robusta (Coffea canephora) have gained commercial importance. During roasting of green coffee beans not only desirable compounds are formed, that exert positive influence on the taste and flavour of coffee, but also small quantities of undesirable ones. Furan (C4H4O) is one of the latter. Furan is a volatile compound (boiling temp. of 31.4 oC) formed during thermal processing of food. The toxicity of furan has been well documented and it is classified as “possible human carcinogen” (Group 2B) by the International Agency for Research on Cancer. Various pathways have been reported for furan formation during food processing. It can be formed from carbohydrates, amino acids by their thermal degradation or thermal re-arrangement and by oxidation of ascorbic acid and polyunsaturated acids and carotenoids. High concentrations of furan have been reported in coffee, baked and roasted food and in food subjected to preserving in cans and jars. Furan levels in brewed coffee are typically near or below 120 μg/L, but it can approach thousands μg/kg in roasted whole beans or ground coffee. The highest concentration of furan in roasted coffee reaches the level of 7000 μg/kg. Taking into account that coffee is the most popular hot drink, it becomes the main contributor to furan exposure from dietary sources for adults. In this article the published scientific papers concerned with the presence of furan in roasted non-brewed and brewed coffee have been reviewed. The formation mechanisms and occurrence of furan in coffee and the harmful influence of furan on the consumer health have been discussed.

In vivo genotoxicity of furan in F344 rats at cancer bioassay doses

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ding, Wei, E-mail: Wei.Ding@fda.hhs.gov; Petibone, Dayton M.; Latendresse, John R.

2012-06-01

Furan, a potent rodent liver carcinogen, is found in many cooked food items and thus represents a human cancer risk. Mechanisms for furan carcinogenicity were investigated in male F344 rats using the in vivo Comet and micronucleus assays, combined with analysis of histopathological and gene expression changes. In addition, formamidopyrimidine DNA glycosylase (Fpg) and endonuclease III (EndoIII)-sensitive DNA damage was monitored as a measure of oxidative DNA damage. Rats were treated by gavage on four consecutive days with 2, 4, and 8 mg/kg bw furan, doses that were tumorigenic in 2-year cancer bioassays, and with two higher doses, 12 andmore » 16 mg/kg. Rats were killed 3 h after the last dose, a time established as producing maximum levels of DNA damage in livers of furan-treated rats. Liver Comet assays indicated that both DNA strand breaks and oxidized purines and pyrimidines increased in a near-linear dose-responsive fashion, with statistically significant increases detected at cancer bioassay doses. No DNA damage was detected in bone marrow, a non-target tissue for cancer, and peripheral blood micronucleus assays were negative. Histopathological evaluation of liver from furan-exposed animals produced evidence of inflammation, single-cell necrosis, apoptosis, and cell proliferation. In addition, genes related to apoptosis, cell-cycle checkpoints, and DNA-repair were expressed at a slightly lower level in the furan-treated livers. Although a mixed mode of action involving direct DNA binding cannot be ruled out, the data suggest that furan induces cancer in rat livers mainly through a secondary genotoxic mechanism involving oxidative stress, accompanied by inflammation, cell proliferation, and toxicity. -- Highlights: ► Furan is a potent rodent liver carcinogen and represents a human cancer risk. ► Furan induces DNA damage in rat liver at cancer bioassay doses. ► Furan induces oxidative stress, inflammation and cell proliferation in rat liver. ► Expression of DNA damage repair-related genes is reduced in furan-treated rat livers. ► Furan induces rat liver cancer mainly through a secondary genotoxic mechanism.« less

Formation of furan and methylfuran by maillard-type reactions in model systems and food.

PubMed

Limacher, Anita; Kerler, Josef; Davidek, Tomas; Schmalzried, Frank; Blank, Imre

2008-05-28

The formation of furan and 2-methylfuran was studied in model systems based on sugars and selected amino acids. Both compounds were preferably formed under roasting conditions in closed systems yielding up to 330 micromol of furan and 260 micromol of 2-methylfuran per mol of precursor. The amounts obtained under pressure cooking conditions were much lower, usually below 20 micromol/mol, except for 2-furaldehyde, which yielded 70-100 micromol/mol of furan. Labeling studies indicated two major formation pathways for both furans: (i) from the intact sugar skeleton and (ii) by recombination of reactive C(2) and/or C(3) fragments. Under roasting conditions in the absence of amino acids, furan was mainly formed from the intact sugar skeleton. Formic and acetic acid were identified as byproducts of sugar degradation, indicating the split off of C(1) and/or C(2) units from hexoses. The presence of alanine, threonine, or serine promoted furan formation by the recombination of C(2) fragments, such as acetaldehyde and glycolaldehyde, which may originate from both sugars and amino acids. In aqueous solution, about half of furan was generated by the recombination of sugar fragments. 2-Methylfuran was preferably formed in the presence of amino acids by aldol-type reactions of C(2) and C(3) fragments with lactaldehyde as a key intermediate, the Strecker aldehyde of threonine. The total furan levels in cooked vegetables were increased by spiking with hexoses. However, in pumpkin puree, only about 20% of furan was formed from sugars, preferably from the intact carbon skeleton.

Furan Decorated Nucleoside Analogues as Fluorescent Probes: synthesis, photophysical evaluation and site-specific incorporation

PubMed Central

Greco, Nicholas J.; Tor, Yitzhak

2007-01-01

The synthesis and photophysical evaluation of modified nucleoside analogues in which a five-membered heterocycle (furan, thiophene, oxazole and thiazole) is attached to the 5 position of 2′-deoxyuridine are reported. The furan containing derivative is identified as the most promising responsive nucleoside of this family due to its emission quantum efficiency and degree of sensitivity to its microenvironment. The furan moiety was then attached to the 5 position of 2′-deoxycytidine as well as the 8 position of adenosine and guanosine. Photophysical evaluation of these four furan containing nucleoside analogues reveal distinct differences in the absorption, emission and quantum efficiency depending upon the class of nucleoside (pyrimidine or purine). Comparing the photophysical properties of all furan containing nucleosides, identifies the furan thymidine analogue, 5-(fur-2-yl)-2′-deoxyuridine, as the best candidate for use as a responsive fluorescent probe in nucleic acids. 5-(fur-2-yl)-2′-deoxyuridine was then converted to the corresponding phosphoramidite and site specifically incorporated into DNA oligonucleotides with greater than 88% coupling efficiency. Such furan-modified oligonucleotides form stable duplexes upon hybridization to their complementary DNA strands and display favorable fluorescent features. PMID:18431439

[Studies on the occurrence of furan in food for infants by gas chromatography with mass spectrometry method].

PubMed

Minorczyk, Maria; Starski, Andrzej; Jedra, Małgorzata; Gawarska, Halina; Sawilska-Rautenstrauch, Dorota

2011-01-01

Furan is an organic compound formed during heat treatment. It has been shown to be carcinogenic in animal laboratory studies. The aim of this study was to determine the content of furan in vegetables and vegetable-meat products intended for infants. The testing system used during this study was gas chromatography coupled with mass spectrometry (GC/MS). The content of furan in 48 samples of processed food ready to eat has been determined. In all samples furan was detected within the range from 13.2 to 91.1 microg/kg, and its average value was 43.3 microg/kg. The paper estimate the exposure assessment of infants to furan found in food. The calculated exposure ranged from 0.23 to 1.77 microg/kg bw/day with the average content of furan in ready to eat products ranged from 35.3 to 52.2 microg/kg. Exposure did not exceed the ADI value 2 microg/kg bw/day.

A new approach to the synthesis of monomers and polymers incorporating furan/maleimide Diels-Alder adducts

NASA Astrophysics Data System (ADS)

Banella, Maria Barbara; Gioia, Claudio; Vannini, Micaela; Colonna, Martino; Celli, Annamaria; Gandini, Alessandro

2016-05-01

The Diels-Alder reaction between furan and maleimide moieties is a well-known and widely used strategy to build bio-based macromolecular structures with peculiar properties. The furan-maleimide adducts are thermally reversible because they can be broken above about 120°C and recombined at lower temperatures. At the moment only the monomers exhibiting the furan or the maleimide moieties on their extremity are used in order to get linear or cross-linked polymeric structures. The innovative idea described here consists in using a monomer bearing two carboxylic acidic groups on its extremities and a furan-maleimide Diels-Alder adduct within its structure. This monomer can give rise to classical polycondensation reactions leading to polymers. These polymers (which are polyesters in the present case) can be broken at high temperatures in correspondence of the furane-maleimide Diels-Alder adduct leading to segments exhibiting furan or maleimide moieties at their extremities, which at lower temperature recombine leading to random or block copolymers.

Formation and reduction of carcinogenic furan in various model systems containing food additives.

PubMed

Kim, Jin-Sil; Her, Jae-Young; Lee, Kwang-Geun

2015-12-15

The aim of this study was to analyse and reduce furan in various model systems. Furan model systems consisting of monosaccharides (0.5M glucose and ribose), amino acids (0.5M alanine and serine) and/or 1.0M ascorbic acid were heated at 121°C for 25 min. The effects of food additives (each 0.1M) such as metal ions (iron sulphate, magnesium sulphate, zinc sulphate and calcium sulphate), antioxidants (BHT and BHA), and sodium sulphite on the formation of furan were measured. The level of furan formed in the model systems was 6.8-527.3 ng/ml. The level of furan in the model systems of glucose/serine and glucose/alanine increased 7-674% when food additives were added. In contrast, the level of furan decreased by 18-51% in the Maillard reaction model systems that included ribose and alanine/serine with food additives except zinc sulphate. Copyright © 2014 Elsevier Ltd. All rights reserved.

Potential protective effect of L-cysteine against the toxicity of acrylamide and furan in exposed Xenopus laevis embryos: an interaction study.

PubMed

Williams, John Russell; Rayburn, James R; Cline, George R; Sauterer, Roger; Friedman, Mendel

2014-08-06

The embryo toxicities of two food-processing-induced toxic compounds, acrylamide and furan, with and without added L-cysteine were examined individually and in mixtures using the frog embryo teratogenesis assay-Xenopus (FETAX). The following measures of developmental toxicity were used: (a) 96 h LC50, the median concentration causing 50% embryo lethality; (b) 96 h EC50, the median concentration causing 50% malformations of the surviving embryos; and (c) teratogenic index (96 h LC50/96 h EC50), an estimate of teratogenic risk. Calculations of toxic units (TU) were used to assess possible antagonism, synergism, or response addition of several mixtures. The evaluated compounds demonstrated counterintuitive effects. Furan had lower than expected toxicity in Xenopus embryos and, unlike acrylamide, does not seem to be teratogenic. However, the short duration of the tests may not show the full effects of furan if it is truly primarily genotoxic and carcinogenic. L-Cysteine showed unexpected properties in the delay of hatching of the embryos. The results from the interaction studies between combination of two or three components (acrylamide plus L-cysteine; furan plus L-cysteine; acrylamide plus furan; acrylamide plus furan and L-cysteine) show that furan and acrylamide seem to have less than response addition at 1:1 toxic unit ratio in lethality. Acrylamide and L-cysteine show severe antagonism even at low 19 acrylamide/1 L-cysteine TU ratios. Data from the mixture of acrylamide, furan, and L-cysteine show a slight antagonism, less than would have been expected from binary mixture exposures. Bioalkylation mechanisms and their prevention are discussed. There is a need to study the toxicological properties of mixtures of acrylamide and furan concurrently formed in heat-processed food.

Synthesis of 2-aryl and 3-aryl benzo[b]furan thioethers using aryl sulfonyl hydrazides as sulfenylation reagents.

PubMed

Zhao, Xia; Zhang, Lipeng; Lu, Xiaoyu; Li, Tianjiao; Lu, Kui

2015-03-06

An efficient, metal-free protocol used to synthesize aryl benzo[b]furan thioethers based on the I2-catalyzed cross-coupling of benzo[b]furans as well as the electrophilic cyclization of 2-alkynylphenol derivatives with aryl sulfonyl hydrazides was developed. Various 2-aryl and 3-aryl benzo[b]furan thioethers were obtained in moderate to good yields.

Occurrence of furan in coffee from Spanish market: Contribution of brewing and roasting.

PubMed

Altaki, M S; Santos, F J; Galceran, M T

2011-06-15

In this work, we evaluated the occurrence of furan in brews obtained from regular, decaffeinated, and instant coffee and commercial packed capsules. For this purpose, a previously developed automated headspace solid-phase microextraction method coupled to gas chromatography-mass spectrometry (HS-SPME-GC-MS) was used. Initially, the influence of HS-SPME conditions on furan formation was evaluated. In addition, the effect of roasting conditions (temperature and time) used for coffee beans on furan formation was also studied. We found that low temperature and long roasting time (140°C and 20min) decreases the final furan content. Furan concentrations in regular ground coffee brews from an espresso coffee machine were higher (43-146ng/ml) than those obtained from a home drip coffee maker (20 and 78ng/ml), while decaffeinated coffee brews from a home drip coffee maker (14-65ng/ml) showed a furan concentration similar to that obtained from regular coffee. Relatively low concentrations of this compound (12-35ng/ml) were found in instant coffee brews, while commercial packed coffee capsules showed the highest concentrations (117-244ng/ml). Finally, the daily intake of furan through coffee consumption in Barcelona (Spain) (0.03-0.38μg/kg of body weight) was estimated. Copyright © 2010 Elsevier Ltd. All rights reserved.

Process for producing furan from furfural aldehyde

DOEpatents

Diebold, James P.; Evans, Robert J.

1988-01-01

A process of producing furan and derivatives thereof is disclosed. The process includes generating furfural aldehyde vapors and then passing those vapors over a zeolite catalyst at a temperature and for a residence time effective to decarbonylate the furfural aldehydes to form furans and derivatives thereof. The resultant furan vapors and derivatives are then separated. In a preferred form, the furfural aldehyde vapors are generated during the process of converting biomass materials to liquid and gaseous fuels.

Process for producing furan from furfural aldehyde

DOEpatents

Diebold, J.P.; Evans, R.J.

1987-04-06

A process of producing furan and derivatives thereof as disclosed. The process includes generating furfural aldehyde vapors and then passing those vapors over a zeolite catalyst at a temperature and for a residence time effective to decarbonylate the furfural aldehydes to form furans and derivatives thereof. The resultant furan vapors and derivatives are then separated. In a preferred form, the furfural aldehyde vapors are generated during the process of converting biomass materials to liquid and gaseous fuels.

Evaluation of serum and liver toxicokinetics for furan and liver DNA adduct formation in male Fischer 344 rats.

PubMed

Churchwell, M I; Scheri, R C; Von Tungeln, L S; Gamboa da Costa, G; Beland, F A; Doerge, D R

2015-12-01

Furan is a food processing contaminant found in many common cooked foods that induces liver toxicity and liver cancer in animal models treated with sufficient doses. The metabolism of furan occurs primarily in the liver where CYP 2E1 produces a highly reactive bis-electrophile, cis-2-butene-1,4-dial (BDA). BDA reacts with nucleophilic groups in amino acids and DNA in vitro to form covalent adducts. Evidence for BDA-nucleoside adduct formation in vivo is limited but important for assessing the carcinogenic hazard of dietary furan. This study used controlled dosing with furan in Fischer 344 rats to measure serum and liver toxicokinetics and the possible formation of BDA-nucleoside adducts in vivo. After gavage exposure, furan concentrations in the liver were consistently higher than those in whole blood (∼6-fold), which is consistent with portal vein delivery of a lipophilic compound into the liver. Formation of BDA-2'-deoxycytidine in furan-treated rat liver DNA was not observed using LC/MS/MS after single doses as high as 9.2 mg/kg bw or repeated dosing for up to 360 days above a consistent background level (1-2 adducts per 10(8) nucleotides). This absence of BDA-nucleoside adduct formation is consistent with the general lack of evidence for genotoxicity of furan in vivo. Published by Elsevier Ltd.

Mutagenicity of furan in female Big Blue B6C3F1 mice

PubMed Central

Terrell, Ashley N.; Huynh, Mailee; Grill, Alex E.; Kovi, Ramesh C.; O’Sullivan, M. Gerard; Guttenplan, Joseph B.; Ho, Yen-Yi; Peterson, Lisa A.

2014-01-01

Furan is an abundant food and environmental contaminant that is a potent liver carcinogen in rodent models. To determine if furan is genotoxic in vivo, female B6C3F1 Big Blue transgenic mice were treated with 15 mg/kg bw furan by gavage 5 days a week for 6 weeks, or once weekly for 3 weeks. Liver cII trans-gene mutation-frequency and mutation spectra were determined. Furan did not increase the mutation frequency under either treatment condition. In the 6-week treatment regimen, there was a change in the cII transgene mutation-spectrum, with the fraction of GC to AT transitions significantly reduced. The only other significant change was an increase in GC to CG transversions; these represented a minor contribution to the overall mutation spectrum. A much larger furan-dependent shift was observed in the 3-week study. There was a significant increase in transversion mutations, predominantly GC to TA transversions as well as smaller non-significant changes in GC to CG and AT to TA transversions. To determine if these mutations were caused by cis-2-butene-1,4-dial (BDA), a reactive metabolite of furan, the mutagenic activity and the mutation spectrum of BDA was determined in vitro, in Big Blue mouse embryonic fibroblasts. This compound did not increase the cII gene mutation-frequency but caused a substantial increase in AT to CG transversions. This increase, however, lost statistical significance when adjusted for multiple comparisons. Together, these findings suggest that BDA may not be directly responsible for the in-vivo effects of furan on mutational spectra. Histopathological analysis of livers from furan-treated mice revealed that furan induced multifocal, hepatocellular necrosis admixed with reactive leukocytes and pigment-laden Kupffer cells, enhanced oval-cell hyperplasia, and increased hepatocyte mitoses, some of which were atypical. An indirect mechanism of genotoxicity is proposed in which chronic toxicity followed by inflammation and secondary cell proliferation triggers cancer development in furan-exposed rodents. PMID:25344163

Furan Levels and Sensory Profiles of Commercial Coffee Products Under Various Handling Conditions.

PubMed

Han, Jeesoo; Kim, Mina K; Lee, Kwang-Geun

2017-11-01

In this study, the levels of furan in coffee with consideration towards common coffee consumption was investigated. The concentration of furan in brewed coffee was the highest among the coffee types studied, with an average of 110.73 ng/mL, followed by canned coffee (28.08 ng/mL) and instant coffee (8.55 ng/mL). In instant and brewed coffee, the furan levels decreased by up to an average of 20% and 22%, after 5 min of pouring in a cup without a lid. The degree of reduction was greater when coffee was served without a lid, regardless of coffee type (P < 0.05). In canned coffee, the level of furan decreased by an average of 14% after storage at 60 °C without a lid, and the degree of furan reduction in coffee was greater in coffee served warm (60 °C) than in coffee served cold (4 °C). A time-dependent intensities of sensory attributes in commercial coffees with various handling condition were different (P < 0.05), suggesting that coffee kept in a cup with lid closed, holds the aroma of coffee longer than coffee in a cup without a lid. Consumption of coffee has increased rapidly in Korea over the past few years. Consequently, the probability of exposure to chemical hazards presence in coffee products increases. Furan is a heterocyclic compound, formed mainly from Maillard reaction, therefore present in coffee products. This work demonstrated the strategy to reduce the levels of furan in coffee products at individual consumer level, by investigating the levels of furan served in common handling scenarios of coffee in Korea: canned coffee, instant coffee, and brewed coffee. Findings of this study can practically guide industry, government, and consumer agencies to reduce the risk exposure to furan during coffee consumptions. © 2017 Institute of Food Technologists®.

Thermodynamic properties of 5(nitrophenyl) furan-2-carbaldehyde isomers.

PubMed

Dibrivnyi, Volodymyr; Sobechko, Iryna; Puniak, Marian; Horak, Yuriy; Obushak, Mykola; Van-Chin-Syan, Yuriy; Andriy, Marshalek; Velychkivska, Nadiia

2015-01-01

The aim of the current work was to determine thermo dynamical properties of 5(2-nitro phenyl)-furan-2-carbaldehyde, 5(3-nitro phenyl)-furan-2-carbaldehyde and 5(4-nitro phenyl)-furan-2-carbaldehyde. The temperature dependence of saturated vapor pressure of 5(2-nitro phenyl)-furan-2-carbaldehyde, 5(3-nitro phenyl)-furan-2-carbaldehyde and 5(4-nitro phenyl)-furan-2-carbaldehyde was determined by Knudsen's effusion method. The results are presented by the Clapeyron-Clausius equation in linear form, and via this form, the standard enthalpies, entropies and Gibbs energies of sublimation and evaporation of compounds were calculated at 298.15 K. The standard molar formation enthalpies of compounds in crystalline state at 298.15 K were determined indirectly by the corresponding standard molar combustion enthalpy, obtained using bomb calorimetry combustion. Determination of the thermodynamic properties for these compounds may contribute to solving practical problems pertaining optimization processes of their synthesis, purification and application and it will also provide a more thorough insight regarding the theoretical knowledge of their nature.Graphical abstract:Generalized structural formula of investigated compounds and their formation enthalpy determination scheme in the gaseous state.

Alkanes from Bioderived Furans by using Metal Triflates and Palladium-Catalyzed Hydrodeoxygenation of Cyclic Ethers.

PubMed

Song, Hai-Jie; Deng, Jin; Cui, Min-Shu; Li, Xing-Long; Liu, Xin-Xin; Zhu, Rui; Wu, Wei-Peng; Fu, Yao

2015-12-21

Using a metal triflate and Pd/C as catalysts, alkanes were prepared from bioderived furans in a one-pot hydrodeoxygenation (HDO) process. During the reaction, the metal triflate plays a crucial role in the ring-opening HDO of furan compounds. The entire reaction process has goes through two major phases: at low temperatures, saturation of the exocyclic double bond and furan ring are catalyzed by Pd/C; at high temperatures, the HDO of saturated furan compounds is catalyzed by the metal triflate. The reaction mechanism was verified by analyzing the changes of the intermediates during the reaction. In addition, different metal triflates, solvents, and catalyst recycling were also investigated. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Abundant Rodent Furan-Derived Urinary Metabolites Are Associated with Tobacco Smoke Exposure in Humans.

PubMed

Grill, Alex E; Schmitt, Thaddeus; Gates, Leah A; Lu, Ding; Bandyopadhyay, Dipankar; Yuan, Jian-Min; Murphy, Sharon E; Peterson, Lisa A

2015-07-20

Furan, a possible human carcinogen, is found in heat treated foods and tobacco smoke. Previous studies have shown that humans are capable of converting furan to its reactive metabolite, cis-2-butene-1,4-dial (BDA), and therefore may be susceptible to furan toxicity. Human risk assessment of furan exposure has been stymied because of the lack of mechanism-based exposure biomarkers. Therefore, a sensitive LC-MS/MS assay for six furan metabolites was applied to measure their levels in urine from furan-exposed rodents as well as in human urine from smokers and nonsmokers. The metabolites that result from direct reaction of BDA with lysine (BDA-N(α)-acetyllysine) and from cysteine-BDA-lysine cross-links (N-acetylcysteine-BDA-lysine, N-acetylcysteine-BDA-N(α)-acetyllysine, and their sulfoxides) were targeted in this study. Five of the six metabolites were identified in urine from rodents treated with furan by gavage. BDA-N(α)-acetyllysine, N-acetylcysteine-BDA-lysine, and its sulfoxide were detected in most human urine samples from three different groups. The levels of N-acetylcysteine-BDA-lysine sulfoxide were more than 10 times higher than that of the corresponding sulfide in many samples. The amount of this metabolite was higher in smokers relative to that in nonsmokers and was significantly reduced following smoking cessation. Our results indicate a strong relationship between BDA-derived metabolites and smoking. Future studies will determine if levels of these biomarkers are associated with adverse health effects in humans.

40 CFR 60.59b - Reporting and recordkeeping requirements.

Code of Federal Regulations, 2010 CFR

2010-07-01

... monitor mercury or dioxin/furan instead of conducting performance testing using EPA manual test methods, all integrated 24-hour mercury concentrations or all integrated 2-week dioxin/furan concentrations as... actions taken. (4) For affected facilities that apply activated carbon for mercury or dioxin/furan control...

40 CFR 60.1900 - What must I include in the semiannual out-of-compliance reports?

Code of Federal Regulations, 2010 CFR

2010-07-01

... for dioxins/furans, cadmium, lead, mercury, particulate matter, opacity, hydrogen chloride, and... actions. (c) For municipal waste combustion units that apply activated carbon to control dioxins/furans or... carbon feed rate established during the most recent mercury and dioxins/furans stack test (as specified...

40 CFR 62.15250 - May I conduct stack testing less often?

Code of Federal Regulations, 2010 CFR

2010-07-01

... pollutants subject to stack testing requirements: dioxins/furans, cadmium, lead, mercury, particulate matter, opacity, hydrogen chloride, and fugitive ash. (b) You can test less often for dioxins/furans emissions if... municipal waste combustion units have demonstrated levels of dioxins/furans emissions less than or equal to...

Reactive Metabolites in the Biotransformation of Molecules Containing a Furan Ring

PubMed Central

Peterson, Lisa A.

2012-01-01

Many xenobiotics containing a furan ring are toxic and/or carcinogenic. The harmful effects of these compounds require furan ring oxidation. This reaction generates an electrophilic intermediate. Depending on the furan ring substituents, the intermediate is either an epoxide or a cis-enedione with more ring substitution favoring epoxide formation. Either intermediate reacts with cellular nucleophiles such as protein or DNA to trigger toxicities. The reactivity of the metabolite determines which cellular nucleophiles are targeted. The toxicity of a particular furan is also influenced by the presence of competing metabolic pathways or efficient detoxification routes. GSH plays an important role in modulating the harmful effects of this class of compound by reacting with the reactive metabolite. However, this may not represent a detoxification step in all cases. PMID:23061605

Combustion chemistry and flame structure of furan group biofuels using molecular-beam mass spectrometry and gas chromatography – Part I: Furan

PubMed Central

Liu, Dong; Togbé, Casimir; Tran, Luc-Sy; Felsmann, Daniel; Oßwald, Patrick; Nau, Patrick; Koppmann, Julia; Lackner, Alexander; Glaude, Pierre-Alexandre; Sirjean, Baptiste; Fournet, René; Battin-Leclerc, Frédérique; Kohse-Höinghaus, Katharina

2013-01-01

Fuels of the furan family, i.e. furan itself, 2-methylfuran (MF), and 2,5-dimethylfuran (DMF) are being proposed as alternatives to hydrocarbon fuels and are potentially accessible from cellulosic biomass. While some experiments and modeling results are becoming available for each of these fuels, a comprehensive experimental and modeling analysis of the three fuels under the same conditions, simulated using the same chemical reaction model, has – to the best of our knowledge – not been attempted before. The present series of three papers, detailing the results obtained in flat flames for each of the three fuels separately, reports experimental data and explores their combustion chemistry using kinetic modeling. The first part of this series focuses on the chemistry of low-pressure furan flames. Two laminar premixed low-pressure (20 and 40 mbar) flat argon-diluted (50%) flames of furan were studied at two equivalence ratios (φ=1.0 and 1.7) using an analytical combination of high-resolution electron-ionization molecular-beam mass spectrometry (EI-MBMS) in Bielefeld and gas chromatography (GC) in Nancy. The time-of-flight MBMS with its high mass resolution enables the detection of both stable and reactive species, while the gas chromatograph permits the separation of isomers. Mole fractions of reactants, products, and stable and radical intermediates were measured as a function of the distance to the burner. A single kinetic model was used to predict the flame structure of the three fuels: furan (in this paper), 2-methylfuran (in Part II), and 2,5-dimethylfuran (in Part III). A refined sub-mechanism for furan combustion, based on the work of Tian et al. [Combustion and Flame 158 (2011) 756-773] was developed which was then compared to the present experimental results. Overall, the agreement is encouraging. The main reaction pathways involved in furan combustion were delineated computing the rates of formation and consumption of all species. It is seen that the predominant furan consumption pathway is initiated by H-addition on the carbon atom neighboring the O-atom with acetylene as one of the dominant products. PMID:24518999

Combustion chemistry and flame structure of furan group biofuels using molecular-beam mass spectrometry and gas chromatography - Part I: Furan.

PubMed

Liu, Dong; Togbé, Casimir; Tran, Luc-Sy; Felsmann, Daniel; Oßwald, Patrick; Nau, Patrick; Koppmann, Julia; Lackner, Alexander; Glaude, Pierre-Alexandre; Sirjean, Baptiste; Fournet, René; Battin-Leclerc, Frédérique; Kohse-Höinghaus, Katharina

2014-03-01

Fuels of the furan family, i.e. furan itself, 2-methylfuran (MF), and 2,5-dimethylfuran (DMF) are being proposed as alternatives to hydrocarbon fuels and are potentially accessible from cellulosic biomass. While some experiments and modeling results are becoming available for each of these fuels, a comprehensive experimental and modeling analysis of the three fuels under the same conditions, simulated using the same chemical reaction model, has - to the best of our knowledge - not been attempted before. The present series of three papers, detailing the results obtained in flat flames for each of the three fuels separately, reports experimental data and explores their combustion chemistry using kinetic modeling. The first part of this series focuses on the chemistry of low-pressure furan flames. Two laminar premixed low-pressure (20 and 40 mbar) flat argon-diluted (50%) flames of furan were studied at two equivalence ratios (φ=1.0 and 1.7) using an analytical combination of high-resolution electron-ionization molecular-beam mass spectrometry (EI-MBMS) in Bielefeld and gas chromatography (GC) in Nancy. The time-of-flight MBMS with its high mass resolution enables the detection of both stable and reactive species, while the gas chromatograph permits the separation of isomers. Mole fractions of reactants, products, and stable and radical intermediates were measured as a function of the distance to the burner. A single kinetic model was used to predict the flame structure of the three fuels: furan (in this paper), 2-methylfuran (in Part II), and 2,5-dimethylfuran (in Part III). A refined sub-mechanism for furan combustion, based on the work of Tian et al. [Combustion and Flame 158 (2011) 756-773] was developed which was then compared to the present experimental results. Overall, the agreement is encouraging. The main reaction pathways involved in furan combustion were delineated computing the rates of formation and consumption of all species. It is seen that the predominant furan consumption pathway is initiated by H-addition on the carbon atom neighboring the O-atom with acetylene as one of the dominant products.

Experimental and theoretical study of oxidative stability of alkylated furans used as gasoline blend components

DOE PAGES

Christensen, Earl; Fioroni, Gina M.; Kim, Seonah; ...

2017-11-06

Alkylated furans such as 2,5-dimethylfuran and 2-methylfuran can be produced from biomass and have very attractive properties for use as spark-ignition fuel blendstocks. Their high octane numbers, relatively high energy density, low water solubility, and minimal effect on gasoline blend volatility are potentially significant advantages over alcohol-based fuels. However, prior studies have reported poor oxidative stability for furanic compound-gasoline blends, as well as the potential for the formation of dangerous organic peroxides. We show that alkylated furans have very low oxidative stability compared to conventional gasoline. Upon oxidation they form highly polar ring-opening products that can react with the startingmore » furanic compound to form dimers, trimers, and higher polymers with intact furan rings. Dimers of the starting furan compounds were also observed. These gasoline-insoluble gums can be problematic for fuel storage or in vehicle fuel systems. Evaporation to dryness under ambient conditions also produced gum with similar composition. Gums produced via evaporation were found to contain peroxides; however, whether these pose a threat of shock initiated explosion has not been determined. We also propose a density functional theory-based analysis of possible reaction pathways, showing that OH radicals can form by reaction of the alkyl group and that addition of OH radicals to the furan ring is energetically favored and leads to ring opening products. As a result, antioxidant additives can be effective at limiting the oxidation reaction in gasoline, but require much higher concentrations than are commonly used in commercial gasolines.« less

Experimental and theoretical study of oxidative stability of alkylated furans used as gasoline blend components

DOE Office of Scientific and Technical Information (OSTI.GOV)

Christensen, Earl; Fioroni, Gina M.; Kim, Seonah

Alkylated furans such as 2,5-dimethylfuran and 2-methylfuran can be produced from biomass and have very attractive properties for use as spark-ignition fuel blendstocks. Their high octane numbers, relatively high energy density, low water solubility, and minimal effect on gasoline blend volatility are potentially significant advantages over alcohol-based fuels. However, prior studies have reported poor oxidative stability for furanic compound-gasoline blends, as well as the potential for the formation of dangerous organic peroxides. We show that alkylated furans have very low oxidative stability compared to conventional gasoline. Upon oxidation they form highly polar ring-opening products that can react with the startingmore » furanic compound to form dimers, trimers, and higher polymers with intact furan rings. Dimers of the starting furan compounds were also observed. These gasoline-insoluble gums can be problematic for fuel storage or in vehicle fuel systems. Evaporation to dryness under ambient conditions also produced gum with similar composition. Gums produced via evaporation were found to contain peroxides; however, whether these pose a threat of shock initiated explosion has not been determined. We also propose a density functional theory-based analysis of possible reaction pathways, showing that OH radicals can form by reaction of the alkyl group and that addition of OH radicals to the furan ring is energetically favored and leads to ring opening products. As a result, antioxidant additives can be effective at limiting the oxidation reaction in gasoline, but require much higher concentrations than are commonly used in commercial gasolines.« less

Same-sample determination of ultratrace levels of polybromodiphenylethers, polybromodibenzo-p-dioxins/furans, and polychlorodibenzo-p-dioxins/furans from combustion flue gas

EPA Science Inventory

The analytical method used for determination of polychlorinated dibenzo-p-dioxins and -furans (PCDDs/Fs) emissions from municipal waste combustors and other stationary sources was modified and validated to enable simultaneous analysis of ultra trace levels of polybrominated diphe...

40 CFR 62.14109 - Reporting and recordkeeping and compliance and performance testing.

Code of Federal Regulations, 2010 CFR

2010-07-01

... dioxin/furan emissions specified in paragraph (d)(1) of this section. (1) If all performance tests for all affected facilities at the MWC plant over a 2-year period indicate that dioxin/furan emissions are... test for dioxin/furan emissions shall be conducted annually (no more than 12 months following the...

40 CFR 60.1875 - What must I include in my initial report?

Code of Federal Regulations, 2010 CFR

2010-07-01

... in table 2 or 4 of this subpart): (1) Dioxins/furans. (2) Cadmium. (3) Lead. (4) Mercury. (5) Opacity... particulate matter control device. Use values established during your initial stack test for dioxins/furans... carbon to control dioxins/furans or mercury emissions, the average carbon feed rates that you recorded...

40 CFR 60.1885 - What must I include in my annual report?

Code of Federal Regulations, 2010 CFR

2010-07-01

...) Dioxins/furans. (2) Cadmium. (3) Lead (4) Mercury. (5) Opacity. (6) Particulate matter. (7) Hydrogen... controlling dioxins/furans or mercury emissions, include four records: (1) The average carbon feed rates recorded during the most recent dioxins/furans and mercury stack tests. (2) The lowest 8-hour block average...

40 CFR 60.1410 - What must I include in my annual report?

Code of Federal Regulations, 2010 CFR

2010-07-01

... units, for eight pollutants, as recorded under § 60.1360(a): (1) Dioxins/furans. (2) Cadmium. (3) Lead...) For municipal waste combustion units that use activated carbon for controlling dioxins/furans or... dioxins/furans and mercury stack tests. (2) The lowest 8-hour block average carbon feed rate recorded...

40 CFR 62.14452 - What test methods and procedures must I use?

Code of Federal Regulations, 2010 CFR

2010-07-01

... total dioxin/furan emissions. The minimum sample time must be 4 hours per test run. If you have selected the toxic equivalency standards for dioxin/furans under § 62.14411, you must use the following procedures to determine compliance: (1) Measure the concentration of each dioxin/furan tetra-through octa...

40 CFR 60.1400 - What must I include in my initial report?

Code of Federal Regulations, 2010 CFR

2010-07-01

... parameters (use appropriate units as specified in table 2 of this subpart): (1) Dioxins/furans. (2) Cadmium... stack test for dioxins/furans emissions and include supporting calculations. (f) If your municipal waste combustion unit uses activated carbon to control dioxins/furans or mercury emissions, the average carbon feed...

40 CFR 62.14455 - What if my HMIWI goes outside of a parameter limit?

Code of Federal Regulations, 2010 CFR

2010-07-01

... temperature (3-hour rolling average) simultaneously The PM, CO, and dioxin/furan emission limits. (c) Except..., daily average for batch HMIWI), and below the minimum dioxin/furan sorbent flow rate (3-hour rolling average) simultaneously The dioxin/furan emission limit. (3) Operates above the maximum charge rate (3...

40 CFR 62.15330 - What must I include in the initial report?

Code of Federal Regulations, 2010 CFR

2010-07-01

... appropriate units as specified in tables 2 or 4 of this subpart): (1) Dioxins/furans. (2) Cadmium. (3) Lead... for dioxins/furans emissions and include supporting calculations. (f) If your municipal waste combustion unit uses activated carbon to control dioxins/furans or mercury emissions, the average carbon feed...

40 CFR 62.15340 - What must I include in the annual report?

Code of Federal Regulations, 2010 CFR

2010-07-01

... § 62.15300(a): (1) Dioxins/furans. (2) Cadmium. (3) Lead. (4) Mercury. (5) Opacity. (6) Particulate... combustion units that use activated carbon for controlling dioxins/furans or mercury emissions, include four records: (1) The average carbon feed rates recorded during the most recent dioxins/furans and mercury...

40 CFR 60.1305 - May I conduct stack testing less often?

Code of Federal Regulations, 2010 CFR

2010-07-01

...: dioxins/furans, cadmium, lead, mercury, particulate matter, opacity, hydrogen chloride, and fugitive ash. (b) You can test less often for dioxins/furans emissions if you own or operate a municipal waste... levels of dioxins/furans emissions less than or equal to 7 nanograms per dry standard cubic meter (total...

Effects of certain polyphenols and extracts on furans and acrylamide formation in model system, and total furans during storage.

PubMed

Oral, Rasim Alper; Dogan, Mahmut; Sarioglu, Kemal

2014-01-01

Using a glucose-glycine and asparagine-fructose system as a Maillard reaction model, the effects of seven polyphenols and solid phase extracts of three plants on the formation of furans and acrylamide were investigated. The polyphenols and extracts were used in biscuit formulation and acrylamide formation was observed. They were used for the storage of the glycine-glucose model system at three different temperatures. The addition of some of the extracts and polyphenols significantly decreased furan formation to different extents. All phenolic compounds and plant extracts decreased in the range of 30.8-85% in the model system except for oleuropein, and all of them decreased in the range of 10.3-19.2% in biscuit. Total furan formation was inhibited by caffeic acid, punicalagin, epicatechin, ECE and PPE during storage. This study evaluated and found the inhibitory effect on the formation of furans and acrylamide in Maillard reactions by the use of some plant extracts and polyphenols. Copyright © 2013 Elsevier Ltd. All rights reserved.

Risk assessment for infants exposed to furan from ready-to-eat thermally processed food products in Poland.

PubMed

Minorczyk, Maria; Góralczyk, Katarzyna; Struciński, Paweł; Hernik, Agnieszka; Czaja, Katarzyna; Łyczewska, Monika; Korcz, Wojciech; Starski, Andrzej; Ludwicki, Jan K

2012-01-01

Thermal processes and long storage of food lead to reactions between reducing sugars and amino acids, or with ascorbic acid, carbohydrates or polyunsaturated fatty acids. As a result of these reactions, new compounds are created. One of these compounds having an adverse effect on human health is furan. The aim of this paper was to estimate the infants exposure to furan found in thermally processed jarred food products, as well as characterizing the risk by comparing the exposure to the reference dose (RfD) and calculating margins of exposure. The material consisted of 301 samples of thermally processed food for infants taken from the Polish market in years 2008 - 2010. The samples included vegetable-meat, vegetables and fruit jarred meals for infants and young children in which the furan levels were analyzed by GC/MS technique. The exposure to furan has been assessed for the 3, 4, 6, 9,12 months old infants using different consumption scenarios. The levels of furan ranged from <1 microg/kg (LOQ) to 166.9 microg/kg. The average furan concentration in all samples was 40.2 microg/kg. The estimated exposures, calculated with different nutrition scenarios, were in the range from 0.03 to 3.56 microg/kg bw/day and exceeded in some cases RfD set at level of 1 microg/kg bw/day. Margins of exposure (MOE) achieved values even below 300 for scenarios assuming higher consumption of vegetable and vegetable-meat products. The magnitude of exposure to furan present in ready-to-eat meals among Polish infants is similar to data reported previously in other European countries but slightly higher than indicated in the recent EFSA report. As for some cases the estimated intake exceeds the RfD, and MOE) values are much lower than 10000 indicating a potential health concern, it is necessary to continue monitoring of furan in jarred food and estimate of its intake by infants.

Multivariate optimization of headspace trap for furan and furfural simultaneous determination in sponge cake.

PubMed

Cepeda-Vázquez, Mayela; Blumenthal, David; Camel, Valérie; Rega, Barbara

2017-03-01

Furan, a possibly carcinogenic compound to humans, and furfural, a naturally occurring volatile contributing to aroma, can be both found in thermally treated foods. These process-induced compounds, formed by close reaction pathways, play an important role as markers of food safety and quality. A method capable of simultaneously quantifying both molecules is thus highly relevant for developing mitigation strategies and preserving the sensory properties of food at the same time. We have developed a unique reliable and sensitive headspace trap (HS trap) extraction method coupled to GC-MS for the simultaneous quantification of furan and furfural in a solid processed food (sponge cake). HS Trap extraction has been optimized using an optimal design of experiments (O-DOE) approach, considering four instrumental and two sample preparation variables, as well as a blocking factor identified during preliminary assays. Multicriteria and multiple response optimization was performed based on a desirability function, yielding the following conditions: thermostatting temperature, 65°C; thermostatting time, 15min; number of pressurization cycles, 4; dry purge time, 0.9min; water / sample amount ratio (dry basis), 16; and total amount (water + sample amount, dry basis), 10g. The performances of the optimized method were also assessed: repeatability (RSD: ≤3.3% for furan and ≤2.6% for furfural), intermediate precision (RSD: 4.0% for furan and 4.3% for furfural), linearity (R 2 : 0.9957 for furan and 0.9996 for furfural), LOD (0.50ng furan g sample dry basis -1 and 10.2ng furfural g sample dry basis -1 ), LOQ (0.99ng furan g sample dry basis -1 and 41.1ng furfural g sample dry basis -1 ). Matrix effect was observed mainly for furan. Finally, the optimized method was applied to other sponge cakes with different matrix characteristics and levels of analytes. Copyright © 2016. Published by Elsevier B.V.

40 CFR 60.1425 - What must I include in the semiannual out-of-compliance reports?

Code of Federal Regulations, 2010 CFR

2010-07-01

...)) show emissions above the limits specified in table 1 of this subpart for dioxins/furans, cadmium, lead... units that apply activated carbon to control dioxins/furans or mercury emissions, include two items: (1... mercury and dioxins/furans stack test (as specified in § 60.1370(a)(1)). Include four items: (i) Eight...

Healable Composites

DTIC Science & Technology

2012-03-28

composites: determine mechanical and crack healing properties (4, 5) Composite (3) Prepreg (2) Polymer (1) Furan (1) Maleimide Healable Composites...5. Characterize the composites: determine mechanical and crack healing properties (4, 5) Composite (3) Prepreg (1) Furan (1) Maleimide (2...Furan (1) Maleimide (4, 5) Composite (3) Prepreg Healable Composites AFOSR FA9550-08-1-0314 Christian Nielsen Challenges • At room temperature

ACB-PCR measurement of spontaneous and furan-induced H-ras codon 61 CAA to CTA and CAA to AAA mutation in B6C3F1 mouse liver.

PubMed

Banda, Malathi; Recio, Leslie; Parsons, Barbara L

2013-10-01

Furan is a rodent liver carcinogen, but the mode of action for furan hepatocarcinogenicity is unclear. H-ras codon 61 mutations have been detected in spontaneous liver tumors of B6C3F1 mice, and the fraction of liver tumors carrying H-ras codon 61 CAA to AAA mutation increased in furan-treated mice. Allele-specific competitive blocker PCR (ACB-PCR) has been used previously to quantify early, carcinogen-induced increases in tumor-associated mutations. The present pilot study investigated whether furan drives clonal expansion of pre-existing H-ras mutant cells in B6C3F1 mouse liver. H-ras codon 61 CAA to CTA and CAA to AAA mutations were measured in DNA isolated from liver tissue of female mice treated with 0, 1, 2, 4, or 8 mg furan/kg body weight, five days per week for three weeks, using five mice per treatment group. Spontaneous levels of mutation were low, with two of five control mice having an H-ras codon 61 CTA or AAA mutant fraction (MF) greater than 10(-5) . Several furan-treated mice had H-ras codon 61 AAA or CTA MFs greater than those measured in control mice and lower bound estimates of induced MF were calculated. However, no statistically-significant differences were observed between treatment groups. Therefore, while sustained exposure to furan is carcinogenic, at the early stage of carcinogenesis examined in this study (three weeks), there was not a significant expansion of H-ras mutant cells. Copyright © 2013 Wiley Periodicals, Inc.

Catalytic Upgrading of Biomass-Derived Compounds via C-C Coupling Reactions. Computational and Experimental Studies of Acetaldehyde and Furan Reactions in HZSM-5

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Cong; Evans, Tabitha J.; Cheng, Lei

2015-10-02

These catalytic C–C coupling and deoxygenation reactions are essential for upgrading of biomass-derived oxygenates to fuel-range hydrocarbons. Detailed understanding of mechanistic and energetic aspects of these reactions is crucial to enabling and improving the catalytic upgrading of small oxygenates to useful chemicals and fuels. Using periodic density functional theory (DFT) calculations, we have investigated the reactions of furan and acetaldehyde in an HZSM-5 zeolite catalyst, a representative system associated with the catalytic upgrading of pyrolysis vapors. Comprehensive energy profiles were computed for self-reactions (i.e., acetaldehyde coupling and furan coupling) and cross-reactions (i.e., acetaldehyde + furan) of this representative mixture. Majormore » products proposed from the computations are further confirmed using temperature controlled mass spectra measurements. Moreover, the computational results show that furan interacts with acetaldehyde in HZSM-5 via an alkylation mechanism, which is more favorable than the self-reactions, indicating that mixing furans with aldehydes could be a promising approach to maximize effective C–C coupling and dehydration while reducing the catalyst deactivation (e.g., coke formation) from aldehyde condensation.« less

An experimental study of furan adsorption and decomposition on vicinal palladium surfaces using scanning tunneling microscopy

NASA Astrophysics Data System (ADS)

Loui, A.; Chiang, S.

2018-04-01

The intact adsorption and decomposition of furan (C4H4O) on vicinal palladium surfaces with (111)-oriented terraces has been studied by scanning tunneling microscopy (STM) over a range of temperatures. STM images at 225 K show that furan molecules lie flat and prefer to adsorb at upper step edges. At 225 K, furan molecules adsorbed on "narrow" terraces of 20 to 45 Å in width appear to diffuse more readily than those adsorbed on "wide" terraces of 160 to 220 Å. A distinct population of smaller features appears in STM images on "narrow" terraces at 288 K and on "wide" terraces at 415 K and is identified with the C3H3 decomposition product, agreeing with prior studies which demonstrated that furan dissociates on Pd(111) to yield carbon monoxide (CO) and a C3H3 moiety in the 280 to 320 K range. Based on our direct visualization of this reaction using STM, we propose a spatial mechanism in which adsorption of furan at upper step edges allows catalysis of the dissociation, followed by diffusion of the product to lower step edges.

Identification of Furan Metabolites Derived from Cysteine-cis-2-Butene-1,4-Dial-Lysine Crosslinks

PubMed Central

Lu, Ding; Peterson, Lisa A.

2010-01-01

Furan is a rodent hepatotoxicant and carcinogen. Since this compound is an important industrial intermediate and has been detected in heat-processed foods and smoke, humans are likely exposed to this toxic compound. Characterization of urinary metabolites of furan will lead to the development of biomarkers to assess human health risks associated with furan exposure. Previous studies indicate that furan is oxidized to a reactive α, β-unsaturated dialdehyde, cis-2-butene-1,4-dial (BDA), in a reaction catalyzed by cytochrome P450. Five previously characterized metabolites are derived from the reaction of BDA with cellular nucleophiles such as glutathione and protein. They include the mono-glutathione reaction product, N-[4-carboxy-4-(3-mercapto-1H-pyrrol-1-yl)-1-oxobutyl]-L-cysteinylglycine cyclic sulfide and its downstream metabolite, S-[1-(1,3-dicarboxypropyl)-1H-pyrrol-3-yl]methylthiol as well as R-2-acetylamino-6-(2,5-dihydro-2-oxo-1H-pyrrol-1-yl)-1-hexanoic acid and N-acetyl-S-[1-(5-acetylamino-5-carboxypentyl)-1H-pyrrol-3-yl]-L-cysteine and its sulfoxide. The last two compounds are downstream metabolites of a BDA-derived cysteine-lysine crosslink, S-[1-(5-amino-5-carboxypentyl)-1H-pyrrol-3-yl]-L-cysteine. In this report, we present the characterization of seven additional urinary furan metabolites, all of which are derived from this crosslink. The cysteinyl residue is subject to several biotransformation reactions, including N-acetylation and S-oxidation. Alternatively, it can undergo β-elimination followed by S-methylation to a methylthiol intermediate that is further oxidized to a sulfoxide. The lysine portion of the crosslink is either N-acetylated or undergoes an oxidative transamination reaction to generate an α-ketoacid metabolite that undergoes oxidative decarboxylation. Some of these metabolites are among the most abundant furan metabolites present in urine as judged by LC-MS/MS analysis, indicating that the oxidation of furan to BDA and BDA’s subsequent reaction with cellular cysteine and lysine residues may represent a significant in vivo pathway of furan biotransformation. Since they are derived from cellular BDA reaction products, these metabolites are markers of furan exposure and bioactivation and could be explored as potential biomarkers in human studies. PMID:20043645

Degraded protein adducts of cis-2-butene-1,4-dial are urinary and hepatocyte metabolites of furan.

PubMed

Lu, Ding; Sullivan, Mathilde M; Phillips, Martin B; Peterson, Lisa A

2009-06-01

Furan is a liver toxicant and carcinogen in rodents. On the basis of these observations and the large potential for human exposure, furan has been classified as a possible human carcinogen. The mechanism of tumor induction by furan is unknown. However, the toxicity requires cytochrome P450-catalyzed oxidation of furan. The product of this oxidation, cis-2-butene-1,4-dial (BDA), reacts readily with glutathione, amino acids, and DNA and is a bacterial mutagen in Ames assay strain TA104. Characterization of the urinary metabolites of furan is expected to provide information regarding the structure(s) of the reactive metabolite(s). Recently, several urinary metabolites have been identified. We reported the presence of a monoglutathione-BDA reaction product, N-[4-carboxy-4-(3-mercapto-1H-pyrrol-1-yl)-1-oxobutyl]-l-cysteinylglycine cyclic sulfide. Three additional urinary metabolites of furan were also characterized as follows: R-2-acetylamino-6-(2,5-dihydro-2-oxo-1H-pyrrol-1-yl)-1-hexanoic acid, N-acetyl-S-[1-(5-acetylamino-5-carboxypentyl)-1H-pyrrol-3-yl]-l-cysteine, and its sulfoxide. It was postulated that these three metabolites are derived from degraded protein adducts. However, the possibility that these metabolites result from the reaction of BDA with free lysine and/or cysteine was not ruled out. In this latter case, one might predict that the reaction of thiol-BDA with free lysine would not occur exclusively on the epsilon-amino group. Reaction of BDA with N-acetylcysteine or GSH in the presence of lysine indicated that both the alpha- and the epsilon-amino groups of lysine can be modified by thiol-BDA. The N-acetylcysteine-BDA-N-acetyllysine urinary metabolites were solely linked through the epsilon-amino group of lysine. A GSH-BDA-lysine cross-link was a significant hepatocyte metabolite of furan. In this case, the major product resulted from reaction with the epsilon-amino group of lysine; however, small amounts of the alpha-amino reaction product were also observed. Western analysis of liver and hepatocyte protein extracts using anti-GSH antibody indicated that GSH was covalently linked to proteins in tissues or cells exposed to furan. Our data support the hypothesis that GSH-BDA can react with either free lysine or protein lysine groups. These data suggest that there are multiple pathways by which furan can modify cellular nucleophiles. In one pathway, BDA reacts directly with proteins to form cysteine-lysine reaction products. In another, BDA reacts with GSH to form GSH-BDA conjugates, which then react with cellular nucleophiles like free lysine or lysine moieties in proteins. Both pathways will give rise to N-acetyl-S-[1-(5-acetylamino-5-carboxypentyl)-1H-pyrrol-3-yl]-l-cysteine. Given the abundance of these metabolites in urine of furan-treated rats, these pathways appear to be major pathways of furan biotransformation in vivo.

Degraded protein adducts of cis-2-butene-1,4-dial are urinary and hepatocyte metabolites of furan

PubMed Central

Lu, Ding; Sullivan, Mathilde M.; Phillips, Martin B.; Peterson, Lisa A.

2009-01-01

Furan is a liver toxicant and carcinogen in rodents. Based on these observations and the large potential for human exposure, furan has been classified as a possible human carcinogen. The mechanism of tumor induction by furan is unknown. However, the toxicity requires cytochrome P450 catalyzed oxidation of furan. The product of this oxidation, cis-2-butene-1,4-dial (BDA), reacts readily with glutathione, amino acids and DNA and is a bacterial mutagen in Ames assay strain TA104. Characterization of the urinary metabolites of furan is expected to provide information regarding the structure(s) of the reactive metabolite(s). Recently, several urinary metabolites have been identified. We reported the presence of a mono-glutathione-BDA reaction product, N-[4-carboxy-4-(3-mercapto-1H-pyrrol-1-yl)-1-oxobutyl]-L-cysteinylglycine cyclic sulfide. Three additional urinary metabolites of furan were also characterized: R-2-acetylamino-6-(2,5-dihydro-2-oxo-1H-pyrrol-1-yl)-1-hexanoic acid, N-acetyl-S-[1-(5-acetylamino-5-carboxypentyl)-1H-pyrrol-3-yl]-L-cysteine and its sulfoxide. It was postulated that these three metabolites are derived from degraded protein adducts. However, the possibility that these metabolites result from reaction of BDA with free lysine and/or cysteine was not ruled out. In this latter case, one might predict that the reaction of thiol-BDA with free lysine would not occur exclusively on the ε-amino group. Reaction of BDA with N-acetylcysteine or GSH in the presence of lysine indicated that both the α- and ε-amino groups of lysine can be modified by thiol-BDA. The N-acetylcysteine-BDA-N-acetyllysine urinary metabolites were solely linked through the ε-amino group of lysine. A GSH-BDA-lysine crosslink was a significant hepatocyte metabolite of furan. In this case, the major product resulted from reaction with the ε-amino group of lysine, however, small amounts of the α-amino reaction product were also observed. Western analysis of liver and hepatocyte protein extracts using anti-GSH antibody indicated that GSH was covalently linked to proteins in tissues or cells exposed to furan. Our data support the hypothesis that GSH-BDA can react with either free lysine or protein lysine groups. These data suggest that there are multiple pathways by which furan can modify cellular nucleophiles. In one pathway, BDA reacts directly with proteins to form cysteine-lysine reaction products. In another, BDA reacts with GSH to form GSH-BDA conjugates which then reacts with cellular nucleophiles like free lysine or lysine moieties in proteins. Both pathways will give rise to N-acetyl-S-[1-(5-acetylamino-5-carboxypentyl)-1H-pyrrol-3-yl]-L-cysteine. Given the abundance of these metabolites in urine of furan-treated rats, these pathways appear to be major pathways of furan biotransformation in vivo. PMID:19441776

Determination of furan levels in commercial samples of baby food from Brazil and preliminary risk assessment.

PubMed

Pavesi Arisseto, A; Vicente, E; De Figueiredo Toledo, M C

2010-08-01

Commercial baby food samples available on the Brazilian market (n = 31) were analysed for furan content using a gas chromatography-mass spectrometry method preceded by solid-phase microextraction. A limit of detection of 0.7 microg kg(-1), a limit of quantitation of 2.4 microg kg(-1), mean recoveries varying from 80% to 107%, and coefficients of variation ranging from 5.6% to 9.4% for repeatability and from 7.4% to 12.4% for within-laboratory reproducibility were obtained during an in-house validation. The levels of furan found in the samples were from not detected to 95.5 microg kg(-1). Samples containing vegetables and meat showed higher furan levels as compared with those containing only fruits. An exposure assessment showed furan intakes up to 2.4 microg kg(-1) body weight day(-1) (99th percentile) for babies fed exclusively with commercial baby foods. Margins of exposure obtained from intakes estimated in this work indicated a potential public health concern.

The application of headspace gas chromatography coupled to tandem quadrupole mass spectrometry for the analysis of furan in baby food samples.

PubMed

Pugajeva, Iveta; Rozentale, Irina; Viksna, Arturs; Bartkiene, Elena; Bartkevics, Vadims

2016-12-01

Selective methodology employing a tandem quadrupole mass spectrometer coupled to a gas chromatograph with headspace autosampler (HS-GC-MS/MS) was elaborated in this study. Application of the elaborated procedure resulted in a limit of detection of 0.021μgkg(-1) and a limit of quantification of 0.071μgkg(-1). The mean recoveries during in-house validation ranged from 89% to 109%, and coefficients of variation for repeatability ranged from 4% to 11%. The proposed analytical method was applied for monitoring the furan content of 30 commercial baby food samples available on the Latvian retail market. The level of furan found in these samples varied from 0.45 to 81.9μgkg(-1), indicating that infants whose sole diet comprises baby food sold in jars and cans are exposed constantly to furan. Samples containing vegetables and meat had higher levels of furan than those containing only fruits. Copyright © 2016 Elsevier Ltd. All rights reserved.

Isomerization of sugars

DOEpatents

Moliner-Marin, Manuel; Roman-Leshkov, Yuriy; Davis, Mark E; Nikolla, Eranda

2014-05-20

Disclosed are processes for isomerizing saccharides. Also disclosed are processes for converting saccharides to furan derivatives. Also disclosed are processes for converting starch to furan derivatives.

Increased Furan Tolerance in Escherichia coli Due to a Cryptic ucpA Gene

PubMed Central

Wang, Xuan; Miller, Elliot N.; Yomano, Lorraine P.; Shanmugam, K. T.

2012-01-01

Expression arrays were used to identify 4 putative oxidoreductases that were upregulated (>3-fold) by furfural (15 mM, 15 min). Plasmid expression of one (ucpA) increased furan tolerance in ethanologenic strain LY180 and wild-type strain W. Deleting ucpA decreased furfural tolerance. Although the mechanism remains unknown, the cryptic ucpA gene is now associated with a phenotype: furan resistance. PMID:22267665

Formation and emission of large furans and oxygenated hydrocarbons from flames

PubMed Central

Johansson, K. Olof; Dillstrom, Tyler; Monti, Matteo; El Gabaly, Farid; Campbell, Matthew F.; Schrader, Paul E.; Popolan-Vaida, Denisia M.; Richards-Henderson, Nicole K.; Wilson, Kevin R.; Violi, Angela; Michelsen, Hope A.

2016-01-01

Many oxygenated hydrocarbon species formed during combustion, such as furans, are highly toxic and detrimental to human health and the environment. These species may also increase the hygroscopicity of soot and strongly influence the effects of soot on regional and global climate. However, large furans and associated oxygenated species have not previously been observed in flames, and their formation mechanism and interplay with polycyclic aromatic hydrocarbons (PAHs) are poorly understood. We report on a synergistic computational and experimental effort that elucidates the formation of oxygen-embedded compounds, such as furans and other oxygenated hydrocarbons, during the combustion of hydrocarbon fuels. We used ab initio and probabilistic computational techniques to identify low-barrier reaction mechanisms for the formation of large furans and other oxygenated hydrocarbons. We used vacuum-UV photoionization aerosol mass spectrometry and X-ray photoelectron spectroscopy to confirm these predictions. We show that furans are produced in the high-temperature regions of hydrocarbon flames, where they remarkably survive and become the main functional group of oxygenates that incorporate into incipient soot. In controlled flame studies, we discovered ∼100 oxygenated species previously unaccounted for. We found that large alcohols and enols act as precursors to furans, leading to incorporation of oxygen into the carbon skeletons of PAHs. Our results depart dramatically from the crude chemistry of carbon- and oxygen-containing molecules previously considered in hydrocarbon formation and oxidation models and spearhead the emerging understanding of the oxidation chemistry that is critical, for example, to control emissions of toxic and carcinogenic combustion by-products, which also greatly affect global warming. PMID:27410045

Formation and emission of large furans and oxygenated hydrocarbons from flames.

PubMed

Johansson, K Olof; Dillstrom, Tyler; Monti, Matteo; El Gabaly, Farid; Campbell, Matthew F; Schrader, Paul E; Popolan-Vaida, Denisia M; Richards-Henderson, Nicole K; Wilson, Kevin R; Violi, Angela; Michelsen, Hope A

2016-07-26

Many oxygenated hydrocarbon species formed during combustion, such as furans, are highly toxic and detrimental to human health and the environment. These species may also increase the hygroscopicity of soot and strongly influence the effects of soot on regional and global climate. However, large furans and associated oxygenated species have not previously been observed in flames, and their formation mechanism and interplay with polycyclic aromatic hydrocarbons (PAHs) are poorly understood. We report on a synergistic computational and experimental effort that elucidates the formation of oxygen-embedded compounds, such as furans and other oxygenated hydrocarbons, during the combustion of hydrocarbon fuels. We used ab initio and probabilistic computational techniques to identify low-barrier reaction mechanisms for the formation of large furans and other oxygenated hydrocarbons. We used vacuum-UV photoionization aerosol mass spectrometry and X-ray photoelectron spectroscopy to confirm these predictions. We show that furans are produced in the high-temperature regions of hydrocarbon flames, where they remarkably survive and become the main functional group of oxygenates that incorporate into incipient soot. In controlled flame studies, we discovered ∼100 oxygenated species previously unaccounted for. We found that large alcohols and enols act as precursors to furans, leading to incorporation of oxygen into the carbon skeletons of PAHs. Our results depart dramatically from the crude chemistry of carbon- and oxygen-containing molecules previously considered in hydrocarbon formation and oxidation models and spearhead the emerging understanding of the oxidation chemistry that is critical, for example, to control emissions of toxic and carcinogenic combustion by-products, which also greatly affect global warming.

Copper-Catalyzed Coupling of 2-Siloxy-1-alkenes and Diazocarbonyl Compounds: Approach to Multisubstituted Furans, Pyrroles, and Thiophenes.

PubMed

Tan, Wei Wen; Yoshikai, Naohiko

2016-07-01

We report herein copper(II)-catalyzed cyclization reactions of silyl enol ethers derived from methyl ketones with α-diazo-β-ketoesters or α-diazoketones to afford 2-siloxy-2,3-dihydrofuran derivatives or 2,3,5-trisubstituted furans, respectively, under mild conditions. The former cyclization products serve as versatile 1,4-diketone surrogates, allowing facile preparation of 2,3,5-trisubstituted furans, pyrroles, and thiophenes.

Irreversible endo-Selective Diels–Alder Reactions of Substituted Alkoxyfurans: A General Synthesis of endo-Cantharimides

PubMed Central

Foster, Robert W; Benhamou, Laure; Porter, Michael J; Bučar, Dejan-Krešimir; Hailes, Helen C; Tame, Christopher J; Sheppard, Tom D

2015-01-01

The [4+2] cycloaddition of 3-alkoxyfurans with N-substituted maleimides provides the first general route for preparing endo-cantharimides. Unlike the corresponding reaction with 3H furans, the reaction can tolerate a broad range of 2-substitued furans including alkyl, aromatic, and heteroaromatic groups. The cycloaddition products were converted into a range of cantharimide products with promising lead-like properties for medicinal chemistry programs. Furthermore, the electron-rich furans are shown to react with a variety of alternative dienophiles to generate 7-oxabicyclo[2.2.1]heptane derivatives under mild conditions. DFT calculations have been performed to rationalize the activation effect of the 3-alkoxy group on a furan Diels–Alder reaction. PMID:25756502

Pyrolysis of furan in a microreactor

NASA Astrophysics Data System (ADS)

Urness, Kimberly N.; Guan, Qi; Golan, Amir; Daily, John W.; Nimlos, Mark R.; Stanton, John F.; Ahmed, Musahid; Ellison, G. Barney

2013-09-01

A silicon carbide microtubular reactor has been used to measure branching ratios in the thermal decomposition of furan, C4H4O. The pyrolysis experiments are carried out by passing a dilute mixture of furan (approximately 0.01%) entrained in a stream of helium through the heated reactor. The SiC reactor (0.66 mm i.d., 2 mm o.d., 2.5 cm long) operates with continuous flow. Experiments were performed with a reactor inlet pressure of 100-300 Torr and a wall temperature between 1200 and 1600 K; characteristic residence times in the reactor are 60-150 μs. The unimolecular decomposition pathway of furan is confirmed to be: furan (+ M) rightleftharpoons α-carbene or β-carbene. The α-carbene fragments to CH2=C=O + HC≡CH while the β-carbene isomerizes to CH2=C=CHCHO. The formyl allene can isomerize to CO + CH3C≡CH or it can fragment to H + CO + HCCCH2. Tunable synchrotron radiation photoionization mass spectrometry is used to monitor the products and to measure the branching ratio of the two carbenes as well as the ratio of [HCCCH2]/[CH3C≡CH]. The results of these pyrolysis experiments demonstrate a preference for 80%-90% of furan decomposition to occur via the β-carbene. For reactor temperatures of 1200-1400 K, no propargyl radicals are formed. As the temperature rises to 1500-1600 K, at most 10% of the decomposition of CH2=C=CHCHO produces H + CO + HCCCH2 radicals. Thermodynamic conditions in the reactor have been modeled by computational fluid dynamics and the experimental results are compared to the predictions of three furan pyrolysis mechanisms. Uncertainty in the pressure-dependency of the initiation reaction rates is a possible a source of discrepancy between experimental results and theoretical predictions.

On the Brønsted acid-catalyzed homogeneous hydrolysis of furans.

PubMed

Nikbin, Nima; Caratzoulas, Stavros; Vlachos, Dionisios G

2013-11-01

Furan affairs: Electronic structure calculations of the homogeneous Brønsted acid-catalyzed hydrolysis of 2,5-dimethylfuran show that proton transfer to the β-position is rate-limiting and provides support that the hydrolysis follows general acid catalysis. By means of projected Fukui indices, we show this to be the case for unsubstituted, 2-, and 2,5-substituted furans with electron-donating groups. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Case study on the utility of hepatic global gene expression profiling in the risk assessment of the carcinogen furan

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jackson, Anna Francina, E-mail: Francina.Jackson@hc-sc.gc.ca; Department of Biology, Carleton University, 1125 Colonel By Drive, Ottawa K1S 5B6; Williams, Andrew, E-mail: Andrew.Williams@hc-sc.gc.ca

2014-01-01

Furan is a chemical hepatocarcinogen in mice and rats. Its previously postulated cancer mode of action (MOA) is chronic cytotoxicity followed by sustained regenerative proliferation; however, its molecular basis is unknown. To this end, we conducted toxicogenomic analysis of B3C6F1 mouse livers following three week exposures to non-carcinogenic (0, 1, 2 mg/kg bw) or carcinogenic (4 and 8 mg/kg bw) doses of furan. We saw enrichment for pathways responsible for cytotoxicity: stress-activated protein kinase (SAPK) and death receptor (DR5 and TNF-alpha) signaling, and proliferation: extracellular signal-regulated kinases (ERKs) and TNF-alpha. We also noted the involvement of NF-kappaB and c-Jun inmore » response to furan, which are genes that are known to be required for liver regeneration. Furan metabolism by CYP2E1 produces cis-2-butene-1,4-dial (BDA), which is required for ensuing cytotoxicity and oxidative stress. NRF2 is a master regulator of gene expression during oxidative stress and we suggest that chronic NFR2 activity and chronic inflammation may represent critical transition events between the adaptive (regeneration) and adverse (cancer) outcomes. Another objective of this study was to demonstrate the applicability of toxicogenomics data in quantitative risk assessment. We modeled benchmark doses for our transcriptional data and previously published cancer data, and observed consistency between the two. Margin of exposure values for both transcriptional and cancer endpoints were also similar. In conclusion, using furan as a case study we have demonstrated the value of toxicogenomics data in elucidating dose-dependent MOA transitions and in quantitative risk assessment. - Highlights: • Global gene expression changes in furan-exposed mouse livers were analyzed. • A molecular mode of action for furan-induced hepatocarcinogenesis is proposed. • Key pathways include NRF2, SAPK, ERK and death receptor signaling. • Important roles for TNF-alpha, c-Jun, and NF-κB in tumorigenesis are proposed. • BMD and MoE values from transcriptional and apical data are compared.« less

Raman and surface enhanced Raman scattering study of the orientation of cruciform 9,10-anthracene thiophene and furan derivatives deposited on a gold colloidal surface

NASA Astrophysics Data System (ADS)

Muñoz-Pérez, J.; Leyton, P.; Paipa, C.; Soto, J. P.; Brunet, J.; Gómez-Jeria, J. S.; Campos-Vallette, M. M.

2016-10-01

The 9,10-di(thiophen-2-yl)anthracene (TAT), 9,10-di(furan-2-yl)anthracene (FAF) and 2-[(10-(thiophen-2-yl)anthracen-9-yl)]furan (TAF) cruciform molecular systems were synthesized using one-step coupling reactions and structurally characterized via Raman, infrared, 1H NMR, 13C NMR and mass spectroscopies. The orientation of the analytes on a gold colloidal surface was inferred from a surface-enhanced Raman scattering (SERS) study. The metal surface interaction was driven by the S and O atoms of the thiophene and furan α-substituents, and the plane of the anthracene fragment remained parallel to the surface. Theoretical calculations based on a simplified molecular model for the analyte-surface interaction provide a good representation of the experimental data.

Combustion chemistry and flame structure of furan group biofuels using molecular-beam mass spectrometry and gas chromatography – Part II: 2-Methylfuran

PubMed Central

Tran, Luc-Sy; Togbé, Casimir; Liu, Dong; Felsmann, Daniel; Oßwald, Patrick; Glaude, Pierre-Alexandre; Fournet, René; Sirjean, Baptiste; Battin-Leclerc, Frédérique; Kohse-Höinghaus, Katharina

2013-01-01

This is Part II of a series of three papers which jointly address the combustion chemistry of furan and its alkylated derivatives 2-methylfuran (MF) and 2,5-dimethylfuran (DMF) under premixed low-pressure flame conditions. Some of them are considered to be promising biofuels. With furan as a common basis studied in Part I of this series, the present paper addresses two laminar premixed low-pressure (20 and 40 mbar) flat argon-diluted (50%) flames of MF which were studied with electron-ionization molecular-beam mass spectrometry (EI-MBMS) and gas chromatography (GC) for equivalence ratios φ=1.0 and 1.7, identical conditions to those for the previously reported furan flames. Mole fractions of reactants, products as well as stable and reactive intermediates were measured as a function of the distance above the burner. Kinetic modeling was performed using a comprehensive reaction mechanism for all three fuels given in Part I and described in the three parts of this series. A comparison of the experimental results and the simulation shows reasonable agreement, as also seen for the furan flames in Part I before. This set of experiments is thus considered to be a valuable additional basis for the validation of the model. The main reaction pathways of MF consumption have been derived from reaction flow analyses, and differences to furan combustion chemistry under the same conditions are discussed. PMID:24518895

Combustion chemistry and flame structure of furan group biofuels using molecular-beam mass spectrometry and gas chromatography - Part II: 2-Methylfuran.

PubMed

Tran, Luc-Sy; Togbé, Casimir; Liu, Dong; Felsmann, Daniel; Oßwald, Patrick; Glaude, Pierre-Alexandre; Fournet, René; Sirjean, Baptiste; Battin-Leclerc, Frédérique; Kohse-Höinghaus, Katharina

2014-03-01

This is Part II of a series of three papers which jointly address the combustion chemistry of furan and its alkylated derivatives 2-methylfuran (MF) and 2,5-dimethylfuran (DMF) under premixed low-pressure flame conditions. Some of them are considered to be promising biofuels. With furan as a common basis studied in Part I of this series, the present paper addresses two laminar premixed low-pressure (20 and 40 mbar) flat argon-diluted (50%) flames of MF which were studied with electron-ionization molecular-beam mass spectrometry (EI-MBMS) and gas chromatography (GC) for equivalence ratios φ=1.0 and 1.7, identical conditions to those for the previously reported furan flames. Mole fractions of reactants, products as well as stable and reactive intermediates were measured as a function of the distance above the burner. Kinetic modeling was performed using a comprehensive reaction mechanism for all three fuels given in Part I and described in the three parts of this series. A comparison of the experimental results and the simulation shows reasonable agreement, as also seen for the furan flames in Part I before. This set of experiments is thus considered to be a valuable additional basis for the validation of the model. The main reaction pathways of MF consumption have been derived from reaction flow analyses, and differences to furan combustion chemistry under the same conditions are discussed.

Body burden levels of dioxin, furans, and PCBs among frequent consumers of Great Lakes sport fish

DOE Office of Scientific and Technical Information (OSTI.GOV)

Falk, C.; Hanrahan, L.; Anderson, H.A.

1999-02-01

Dioxins, furans, and polychlorinated biphenyls (PCBs) are toxic, persist in the environment, and bioaccumulate to concentrations that can be harmful to humans. The Health Departments of five GL states, Wisconsin, Michigan, Ohio, Illinois, and Indiana, formed a consortium to study body burden levels of chemical residues in fish consumers of Lakes Michigan, Huron, and Erie. In Fall 1993, a telephone survey was administered to sport angler households to obtain fish consumption habits and demographics. A blood sample was obtained from a portion of the study subjects. One hundred serum samples were analyzed for 8 dioxin, 10 furan, and 4 coplanarmore » PCB congeners. Multiple linear regression was conducted to assess the predictability of the following covariates: GL sport fish species, age, BMI, gender, years sport fish consumed, and lake. Median total dioxin toxic equivalents (TEq), total furan TEq, and total coplanar PCB TEq were higher among all men than all women (P = 0.0001). Lake trout, salmon, age, BMI, and gender were significant regression predictors of log (total coplanar PCBs). Lake trout, age, gender, and lake were significant regression predictors of log (total furans). Age was the only significant predictor of total dioxin levels.« less

Furan production from glycoaldehyde over HZSM-5

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, Seonah; Evans, Tabitha J.; Mukarakate, Calvin

Catalytic fast pyrolysis of biomass over zeolite catalysts results primarily in aromatic (e.g. benzene, toluene, xylene) and olefin products. However, furans are a higher value intermediate for their ability to be readily transformed into gasoline, diesel, and chemicals. Here we investigate possible mechanisms for the coupling of glycoaldehyde, a common product of cellulose pyrolysis, over HZSM-5 for the formation of furans. Experimental measurements of neat glycoaldehyde over a fixed bed of HZSM-5 confirm furans (e.g. furanone) are products of this reaction at temperatures below 300 degrees C with several aldol condensation products as co-products (e.g. benzoquinone). However, under typical catalyticmore » fast pyrolysis conditions (>400 degrees C), further reactions occur that lead to the usual aromatic product slate. ONIOM calculations were utilized to identify the pathway for glycoaldehyde coupling toward furanone and hydroxyfuranone products with dehydration reactions serving as the rate determining steps with typical intrinsic reaction barriers of 40 kcal mol-1. The reaction mechanisms for glycoaldehyde will likely be similar to that of other small oxygenates such as acetaldehyde, lactaldehyde, and hydroxyacetone and this study provides a generalizable mechanism of oxygenate coupling and furan formation over zeolite catalysts.« less

How ingredients influence furan and aroma generation in sponge cake.

PubMed

Cepeda-Vázquez, Mayela; Rega, Barbara; Descharles, Nicolas; Camel, Valérie

2018-04-15

A wide range of compounds can be formed during thermal processing of food, some of which are relevant for aroma (e.g., furfural), while others are of great health concern (e.g., furan). This paper presents the study of formulation as affecting the simultaneous generation of furan and furfural, along with other aroma quality markers, in sponge cake by means of headspace trap/GC-MS. Ingredients were screened according to their category (fat, salt, sugar, egg-based). Glucose-containing formulation resulted in the highest content of furan and furfural (12.5 ± 0.5 ng g -1 and 9.2 ± 0.2 μg g -1 , dry basis, respectively), while their lowest amount was found in the egg-white recipe (3.1 ± 0.1 ng g -1 for furan and 0.287 ± 0.078 µg g -1 for furfural, dry basis). The latter also related negatively to all studied compounds. This work will be useful for developing novel strategies to deliver safe foods with appealing organoleptic attributes. Copyright © 2017 Elsevier Ltd. All rights reserved.

Isolation of a furan fatty acid from Hevea brasiliensis latex employing the combined use of pH-zone-refining and conventional countercurrent chromatography.

PubMed

Englert, Michael; Ulms, Kerstin; Wendlinger, Christine; Vetter, Walter

2016-02-01

Furan fatty acids are valuable and bioactive minor fatty acids that usually contribute <0.1% to the fatty acid content of food samples. Their biological role still remains unclear as authentic furan fatty acid standards are not readily available and thorough experimental studies verifying the relevance of furan fatty acids are thus virtually impossible. An efficient protocol for the isolation of the furan fatty acid 9-(3-methyl-5-pentylfuran-2-yl)-nonanoic acid from hydrolyzed and centrifuged latex of Hevea brasiliensis was developed using countercurrent chromatography. A first run using pH-zone-refining countercurrent chromatography provided 48.4 mg of 9-(3-methyl-5-pentylfuran-2-yl)-nonanoic acid from 210 mg latex extract in a purity of 95%. The purity was increased to 99% by means of one second run in conventional countercurrent chromatography mode. The Structure and purity of 9-(3-methyl-5-pentylfuran-2-yl)-nonanoic acid were determined by gas chromatography coupled to mass spectrometry and (1)H and (13)C NMR spectroscopy. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Furan production from glycoaldehyde over HZSM-5

DOE PAGES

Kim, Seonah; Evans, Tabitha J.; Mukarakate, Calvin; ...

2016-04-03

Catalytic fast pyrolysis of biomass over zeolite catalysts results primarily in aromatic (e.g. benzene, toluene, xylene) and olefin products. However, furans are a higher value intermediate for their ability to be readily transformed into gasoline, diesel, and chemicals. Here we investigate possible mechanisms for the coupling of glycoaldehyde, a common product of cellulose pyrolysis, over HZSM-5 for the formation of furans. Experimental measurements of neat glycoaldehyde over a fixed bed of HZSM-5 confirm furans (e.g. furanone) are products of this reaction at temperatures below 300 degrees C with several aldol condensation products as co-products (e.g. benzoquinone). However, under typical catalyticmore » fast pyrolysis conditions (>400 degrees C), further reactions occur that lead to the usual aromatic product slate. ONIOM calculations were utilized to identify the pathway for glycoaldehyde coupling toward furanone and hydroxyfuranone products with dehydration reactions serving as the rate determining steps with typical intrinsic reaction barriers of 40 kcal mol-1. The reaction mechanisms for glycoaldehyde will likely be similar to that of other small oxygenates such as acetaldehyde, lactaldehyde, and hydroxyacetone and this study provides a generalizable mechanism of oxygenate coupling and furan formation over zeolite catalysts.« less

40 CFR 62.15160 - What emission limits must I meet?

Code of Federal Regulations, 2010 CFR

2010-07-01

... modification after June 26, 1987, then you must comply with the dioxins/furans and mercury emission limits... operating permit, if a permit modification is required. Final compliance with the dioxins/furans limits must...

Polyamide copolymers having 2,5-furan dicarboxamide units

DOEpatents

Chisholm, Bret Ja; Samanta, Satyabrata

2017-09-19

Polyamide copolymers, and methods of making and using polyamide copolymers, having 2,5-furan dicarboxamide units are disclosed herein. Such polymers can be useful for engineering thermoplastics having advantageous physical and/or chemical properties.

Electron-impact vibrational excitation of furan

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hargreaves, L. R.; Albaridy, R.; Serna, G.

2011-12-15

We report measurements of differential cross sections for the vibrational excitation of furan (C{sub 4}H{sub 4}O), obtaining results for nine features spanning the electron energy loss range from 0 to 0.8 eV, at electron-impact energies of 5, 6, 7.5, 10, and 15 eV and for scattering angles ranging from 10{sup o} to 130{sup o}. The normalization of the differential cross sections was done using elastic differential cross sections for furan determined earlier by our group [Khakoo et al., Phys. Rev A 81, 062716 (2010)].

Designed synthesis and supramolecular architectures of furan-substituted perylene diimide.

PubMed

Yu, Yanwen; Li, Yongjun; Qin, Zhihong; Jiang, Runsheng; Liu, Huibiao; Li, Yuliang

2013-06-01

Novel furan-substituted perylene diimides are successfully synthesized and an efficient supramolecular architecture approach to construct zero/one-dimensional nano- and micro-structures by controlling solvents has been demonstrated. The aggregate structure conversion in different molecular structures can be controlled in the form of sphere-like, rod-like, and vesicle-like structures. As expected, these solid supramolecular rod-like architectures displayed interesting optical waveguide behavior, which indicates the aggregate structure materials of furan-substituted perylene diimides have the potential application as micro-scale photonic elements. Copyright © 2013 Elsevier Inc. All rights reserved.

Structure-Odor Correlations in Homologous Series of Mercapto Furans and Mercapto Thiophenes Synthesized by Changing the Structural Motifs of the Key Coffee Odorant Furan-2-ylmethanethiol.

PubMed

Schoenauer, Sebastian; Schieberle, Peter

2018-04-25

Furan-2-ylmethanethiol (2-furfurylthiol; 2-FFT, 1) is long-known as a key odorant in roast and ground coffee and was also previously identified in a wide range of thermally treated foods such as meat, bread, and roasted sesame seeds. Its unique coffee-like odor quality elicited at very low concentrations, and the fact that only a very few compounds showing a similar structure have previously been described in foods make 1 a suitable candidate for structure-odor activity studies. To gain insight into the structural features needed to evoke a coffee-like odor at low concentrations, 46 heterocyclic mercaptans and thio ethers were synthesized, 32 of them for the first time, and their odor qualities and odor thresholds were determined. A movement of the mercapto group to the 3-position kept the coffee-like aroma but led to an increase in odor threshold. A separation of the thiol group from the furan ring by an elongation of the carbon side chain caused a loss of the coffee-like odor and also led to an increase in odor thresholds, especially for ω-(furan-2-yl)alkane-1-thiols with six or seven carbon atoms in the side chain. A displacement of the furan ring by a thiophene ring had no significant influence on the odor properties of most of the compounds studied, but the newly synthesized longer-chain 1-(furan-2-yl)- and 1-(thiophene-2-yl)alkane-1-thiols elicited interesting passion fruit-like scents. In total, only 4 out of the 46 compounds also showed a coffee-like odor quality like 1, but none showed a lower odor threshold. Besides the odor attributes, also retention indices, mass spectra, and NMR data of the synthesized compounds were elaborated, which are helpful in possible future identification of these compounds in trace levels in foods or other materials.

Furan

Integrated Risk Information System (IRIS)

Furan ; CASRN 110 - 00 - 9 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic Effects ) a

Effect of high hydrostatic pressure on background microflora and furan formation in fruit purée based baby foods.

PubMed

Kultur, Gulcin; Misra, N N; Barba, Francisco J; Koubaa, Mohamed; Gökmen, Vural; Alpas, Hami

2018-03-01

The baby foods industry is currently seeking technologies to pasteurize products without formation of processing contaminants such as furan. This work demonstrates the applicability of high hydrostatic pressure (HHP) as a non-thermal decontamination intervention for fruit purée based baby foods. HHP processing was evaluated at 200, 300, and 400 MPa pressures, for 5, 10 and 15 min of treatment times at 25, 35 and 45 °C. HHP application at 400 MPa, 45 °C for 15 min ensured complete inactivation (about 6 log 10 ) of total mesophilic aerophiles, as well as yeasts and molds. No furan was detected in HHP processed products. Thus, the key advantage of HHP over thermal processing is the ability to achieve commercially acceptable microbiological inactivation while avoiding the formation of processing contaminants such as furan.

Broadband Microwave Study of Reaction Intermediates and Products Through the Pyrolysis of Oxygenated Biofuels

NASA Astrophysics Data System (ADS)

Abeysekera, Chamara; Hernandez-Castillo, Alicia O.; Fritz, Sean; Zwier, Timothy S.

2017-06-01

The rapidly growing list of potential plant-derived biofuels creates a challenge for the scientific community to provide a molecular-scale understanding of their combustion. Development of accurate combustion models rests on a foundation of experimental data on the kinetics and product branching ratios of their individual reaction steps. Therefore, new spectroscopic tools are necessary to selectively detect and characterize fuel components and reactive intermediates generated by pyrolysis and combustion. Substituted furans, including furanic ethers, are considered second-generation biofuel candidates. Following the work of the Ellison group, an 8-18 GHz microwave study was carried out on the unimolecular and bimolecular decomposition of the smallest furanic ether, 2-methoxy furan, and it`s pyrolysis intermediate, the 2-furanyloxy radical, formed in a high-temperature pyrolysis source coupled to a supersonic expansion. Details of the experimental setup and analysis of the spectrum of the radical will be discussed.

Metabolomic approach for determination of key volatile compounds related to beef flavor in glutathione-Maillard reaction products.

PubMed

Lee, Sang Mi; Kwon, Goo Young; Kim, Kwang-Ok; Kim, Young-Suk

2011-10-10

The non-targeted analysis, combining gas chromatography coupled with time-of-flight mass spectrometry (GC-TOF/MS) and sensory evaluation, was applied to investigate the relationship between volatile compounds and the sensory attributes of glutathione-Maillard reaction products (GSH-MRPs) prepared under different reaction conditions. Volatile compounds in GSH-MRPs correlating to the sensory attributes were determined using partial least-squares (PLS) regression. Volatile compounds such as 2-methylfuran-3-thiol, 3-sulfanylpentan-2-one, furan-2-ylmethanethiol, 2-propylpyrazine, 1-furan-2-ylpropan-2-one, 1H-pyrrole, 2-methylthiophene, and 2-(furan-2-ylmethyldisulfanylmethyl)furan could be identified as possible key contributors to the beef-related attributes of GSH-MRPs. In this study, we demonstrated that the unbiased non-targeted analysis based on metabolomic approach allows the identification of key volatile compounds related to beef flavor in GSH-MRPs. Copyright © 2011 Elsevier B.V. All rights reserved.

Changes in chemical composition of frozen coated fish products during deep-frying.

PubMed

Pérez-Palacios, Trinidad; Petisca, Catarina; Casal, Susana; Ferreira, Isabel M P L V O

2014-03-01

This work evaluates the influence of deep-frying coated fish products on total fat, fatty acid (FA) and amino acid profile, and on the formation of volatile compounds, with special attention on furan and its derivatives due to their potential harmful characteristics. As expected, deep-frying in sunflower oil increased linoleic acid content, but total fat amount increased only by 2% on a dry basis. Eicosapentanoic and docosahexanoic acids were preserved while γ- and α-linoleic acids were oxidised. Deep-frying also induces proteolysis, releasing free AA, and the formation of volatile compounds, particularly aldehydes and ketones arising from polyunsaturated FA. In addition, high quantities of furanic compounds, particularly furan and furfuryl alcohol, are generated during deep-frying coated fish. The breaded crust formed could contribute simultaneously for the low uptake of fat, preservation of long chain n-3 FA, and for the high amounts of furanic compounds formed during the deep-frying process.

Investigation of Thermochemistry Associated with the Carbon–Carbon Coupling Reactions of Furan and Furfural Using ab Initio Methods

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Cong; Assary, Rajeev S.; Curtiss, Larry A.

2014-06-26

Upgrading of furan and small oxygenates obtained from the decomposition of cellulosic materials via formation of carbon-carbon bonds is critical to effective conversion of biomass to liquid transportation fuels. Simulation-driven molecular level understanding of carbon-carbon bond formation is required to design efficient catalysts and processes. Accurate quantum chemical methods are utilized here to predict the reaction energetics for conversion of furan (C4H4O) to C5-C8 ethers and the transformation of furfural (C5H6O2) to C13-C26 alkanes. Furan, can be coupled with various C1 to C4 lower molecular weight carbohydrates obtained from the pyrolysis via Diels-Alder type reactions in the gas phase tomore » produce C5-C8 cyclic ethers. The computed reaction barriers for these reactions (~25 kcal/mol) are lower than the cellulose activation or decomposition reactions (~50 kcal/mol). Cycloaddition of C5-C8 cyclo-ethers with furans can also occur in the gas phase, and the computed activation energy is similar to that of the first Diels-Alder reaction. Furfural, obtained from biomass, can be coupled with aldehydes or ketones with α-hydrogen atoms to form longer chain aldol products and these aldol products can undergo vapor phase hydrocycloaddition (activation barrier of ~20 kcal/mol) to form the precursors of C26 cyclic hydrocarbons. These thermochemical studies provide the basis for further vapor phase catalytic studies required for upgrading of furans/furfurals to longer chain hydrocarbons.« less

Formation and emission of large furans and oxygenated hydrocarbons from flames

DOE PAGES

Johansson, K. Olof; Dillstrom, Tyler; Monti, Matteo; ...

2016-07-07

Many oxygenated hydrocarbon species formed during combustion, such as furans, are highly toxic and detrimental to human health and the environment. These species may also increase the hygroscopicity of soot and strongly influence the effects of soot on regional and global climate. However, large furans and associated oxygenated species have not previously been observed in flames, and their formation mechanism and interplay with polycyclic aromatic hydrocarbons (PAHs) are poorly understood. We report on a synergistic computational and experimental effort that elucidates the formation of oxygen-embedded compounds, such as furans and other oxygenated hydrocarbons, during the combustion of hydrocarbon fuels. Wemore » used ab initio and probabilistic computational techniques to identify low-barrier reaction mechanisms for the formation of large furans and other oxygenated hydrocarbons. We used vacuum-UV photoionization aerosol mass spectrometry and X-ray photoelectron spectroscopy to confirm these predictions. We show that fura ns are produced in the high- Temperature regions of hydrocarbon flames, where they remarkably survive and become the main functional group of oxygenates that incorporate into incipient soot. In controlled flame studies, we discovered ~100 oxygenated species previously unaccounted for. We found that large alcohols and enols act as precursors to furans, leading to incorporation of oxygen into the carbon skeletons of PAHs. Our results depart dramatically from the crude chemistry of carbonand oxygen-containing molecules previously considered in hydrocarbon formation and oxidation models and spearhead the emerging understanding of the oxidation chemistry that is critical, for example, to control emissions of toxic and carcinogenic combustion by-products, which also greatly affect global warming.« less

40 CFR 60.1820 - How do I monitor the injection rate of activated carbon?

Code of Federal Regulations, 2010 CFR

2010-07-01

... activated carbon? If your municipal waste combustion unit uses activated carbon to control dioxins/furans or... dioxins/furans and mercury stack test, determine the average carbon feed rate in kilograms (or pounds) per...

40 CFR 62.15275 - How do I monitor the injection rate of activated carbon?

Code of Federal Regulations, 2010 CFR

2010-07-01

... carbon? If your municipal waste combustion unit uses activated carbon to control dioxins/furans or... dioxins/furans and mercury stack test, determine the average carbon feed rate in kilograms (or pounds) per...

40 CFR 60.1330 - How do I monitor the injection rate of activated carbon?

Code of Federal Regulations, 2010 CFR

2010-07-01

... combustion unit uses activated carbon to control dioxins/furans or mercury emissions, you must meet three... feed rate (for example, screw feeder speed). (b) During each dioxins/furans and mercury stack test...

40 CFR 60.1360 - What records must I keep for stack tests?

Code of Federal Regulations, 2010 CFR

2010-07-01

... measure specified in table 1 of this subpart: (1) Dioxins/furans. (2) Cadmium. (3) Lead. (4) Mercury. (5... control device during all stack tests for dioxins/furans emissions. (d) The calendar date of each record. ...

Dioxins, Furans, PCBs, and Congeners Analytical Service within the Superfund Contract Laboratory Program

EPA Pesticide Factsheets

This page contains information about the DLM02.2 analytical service for the analysis of dioxins and furans at hazardous waste sites. The SOW contains the analytical method and contractual requirements for laboratories.

40 CFR 60.38b - Compliance and performance testing.

Code of Federal Regulations, 2010 CFR

2010-07-01

... dioxins/furans specified in § 60.58b(g)(5)(iii) of subpart Eb of this part, as applicable, for those designated facilities that achieve a dioxin/furan emission level less than or equal to 15 nanograms per dry...

40 CFR 60.1845 - What records must I keep for stack tests?

Code of Federal Regulations, 2010 CFR

2010-07-01

... recorded in the appropriate units of measure specified in table 2 or 4 of this subpart: (1) Dioxins/furans... temperature at the inlet of your particulate matter control device during all stack tests for dioxins/furans...

ETV TEST OF PCDD/F EMISSIONS MONITORING SYSTEMS

EPA Science Inventory

Four polychlorinated dibenzodioxin and furan (PCDD/F) emission monitors were tested under the EPA Environmental Technology and Verification (ETV) program. Two long-term sampling devices, the DioxinMonitoringSystem and Adsorption Method for Sampling Dioxins and Furans, and two sem...

40 CFR 60.2125 - How do I conduct the initial and annual performance test?

Code of Federal Regulations, 2011 CFR

2011-07-01

... the concentration of each dioxin/furan tetra-through octa-chlorinated isomer emitted using EPA Method 23 at 40 CFR part 60, appendix A-7. (2) For each dioxin/furan (tetra-through octa-chlorinated) isomer...

Synthesis and structure-activity relationship studies of furan-ring fused chalcones as antiproliferative agents.

PubMed

Saito, Yusuke; Kishimoto, Maho; Yoshizawa, Yuko; Kawaii, Satoru

2015-02-01

As part of our continuing investigation of flavonoid derivatives as potential anticancer substances, the synthesis of 25 cinnamoyl derivatives of benzofuran as furan-fused chalcones was carried-out and these compounds were further evaluated for their antiproliferative activity towards HL60 promyelocytic leukemia cells. In comparison with 2',4'-dihydroxychalcone, attachment of a furan moiety on the A-ring enhanced activity by more than twofold. Benzofurans may be useful in the design of biologically active flavonoids. Copyright© 2015 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

Furan fatty acids - Beneficial or harmful to health?

PubMed

Xu, Long; Sinclair, Andrew J; Faiza, Muniba; Li, Daoming; Han, Xianlin; Yin, Huiyong; Wang, Yonghua

2017-10-01

Furan fatty acids are found in plants, algae, and fish, and reported to have some positive health benefits, including anti-oxidant and anti-inflammatory activities, and inhibition of non-enzymatic lipid peroxidation. A major metabolite of furan fatty acids, 3-carboxy-4-methyl-5-propyl-2-furanpropanoic acid (CMPF), has been reported to be increased in patients who progress from prediabetes to type 2 diabetes, although CMPF is not necessarily associated with impaired glucose metabolism. Other studies report that CMPF levels are lower in subjects with diabetes than control subjects. Plasma CMPF levels increase in subjects who consume fish or fish oil, and in patients with renal failure. It is not known where furan fatty acids are converted to CMPF and it is speculated that this might be a result of microbiome activity. The plasma levels reported for CMPF in healthy, diabetic and patients with renal disease vary by factors of more than 100-fold within each of these three groups, so measurement error appears to be limiting the ability to interpret studies. This review explores these controversies and raises questions about whether CMPF is a marker for healthy diets or indeed associated with diabetes and renal health. The review concludes that, on balance, furan fatty acids are beneficial for health. Copyright © 2017 Elsevier Ltd. All rights reserved.

40 CFR 60.4885 - How and when do I demonstrate continuous compliance with the emission limits and standards?

Code of Federal Regulations, 2011 CFR

2011-07-01

... concentration of each dioxin/furan tetra- through octa-chlorinated isomer emitted using EPA Method 23. (2) For each dioxin/furan (tetra- through octa-chlorinated) isomer measured in accordance with paragraph (c)(1...

Sustainable pathway to furanics from biomass via heterogeneous organo-catalysis

EPA Science Inventory

An organic sulfonated graphitic carbon nitride is synthesized and its application has been demonstrated inthe conversion of carbohydrates into furanics and related value-added products. The most importantfeature of the material is the stability and acidity, which could be utilize...

Hydrogen bond docking preference in furans: Osbnd H ⋯ π vs. Osbnd H ⋯ O

NASA Astrophysics Data System (ADS)

Jiang, Xiaotong; Tsona, Narcisse T.; Tang, Shanshan; Du, Lin

2018-02-01

The docking sites of hydrogen bonds in complexes formed between 2,2,2-trifluoroethanol (TFE), furan (Fu), and 2-methyl furan (MF) have been investigated. Using density functional theory (DFT) calculations, gas phase and matrix isolation FTIR spectroscopies, the strengths of Osbnd H ⋯ O and Osbnd H ⋯ π hydrogen bonds in the complexes were compared to find the docking preference. Calculations suggest that the hydrogen bond donor, TFE, is more likely to dock onto the oxygen atom of the aromatic furans ring, and consequently, the Osbnd H ⋯ O type hydrogen bond is relatively stronger than the Osbnd H ⋯ π type. The FTIR spectrum in the OH-stretching fundamental range obtained at room temperatures has been compared with that obtained at extremely low temperatures in the matrix. The fundamental and the red shifts of OH-stretching vibrations were observed in both FTIR spectra, confirming the formation of hydrogen bonded complexes. By assessing the ability of furan and MF to participate in the formation of Osbnd H ⋯ O hydrogen bond, the effect of ring methylation has been highlighted. From the calculated geometric and thermodynamic parameters as well as the frequency shift of the OH-stretching vibrations in complexes, TFE-MF is found to be more stable than TFE-Fu, which suggests that the strength of the Osbnd H ⋯ O hydrogen bond in TFE-MF originates from the high activity of the furan molecule caused by the methylation of the aromatic ring. The present study furthers the knowledge of docking preference in heteroaromatic molecules and is helpful to understand the nature of intermolecular interactions between hydrogen bond donors and acceptors, including both electron-deficient atoms and π cloud.

40 CFR 60.1535 - What compliance schedule must I include in my State plan?

Code of Federal Regulations, 2010 CFR

2010-07-01

.... (2) For Class I units (see definition in § 60.1940), dioxins/furans stack test results for at least... comply with the dioxins/furans and mercury limits specified in tables 2 and 3 of this subpart by the...

DISTRIBUTION OF DIOXINS, FURANS, AND COPLANAR PCBS IN DIFFERENT FAT MATRICES IN CATTLE

EPA Science Inventory

The United States Environmental Protection Agency (EPA) and the United States Department of Agriculture (USDA) recently collaborated on a statistically-based, national survey of dioxin-like compounds, including dioxins, furans, and coplanar PCBs, in the back fat from slaughtered ...

Sustainable pathway to furanics from biomass via heterogeneous organo-catalysis

EPA Science Inventory

An organic sulfonated graphitic carbon nitride is synthesized and its application has been demonstrated in the conversion of carbohydrates into furanics and related value-added products. The most important feature of the material is the stability and acidity, which could be utili...

Effects of furan derivatives on biohydrogen fermentation from wet steam-exploded cornstalk and its microbial community.

PubMed

Liu, Zhidan; Zhang, Chong; Wang, Linjun; He, Jianwei; Li, Baoming; Zhang, Yuanhui; Xing, Xin-Hui

2015-01-01

Understanding the role of furan derivatives, furfural (FUR) and 5-hydroxymethyl furfural (HMF), is important for biofuel production from lignocellulosic biomass. In this study, the effects of furan derivatives on hydrogen fermentation from wet steam-exploded cornstalk were investigated. The control experiments with only seed sludge indicated that HMF addition of up to 1g/L stimulated hydrogen production. Similar results were obtained using steam-exploded cornstalk as the feedstock. Hydrogen productivity was increased by up to 40% with the addition of HMF. In addition, over 90% of furan derivatives with an initial concentration below 1g/L were degraded. Pyosequencing showed that the addition of HMF and FUR resulted in different microbial communities. HMF led to a higher proportion of the genera Clostridium and Ruminococcaceae, supporting the increased hydrogen production. This study suggested that hydrogen fermentation could be a detoxifying step for steam-exploded cornstalk, and HMF and FUR exhibited different functions for hydrogen fermentation. Copyright © 2014 Elsevier Ltd. All rights reserved.

Occurrence of furan in commercial processed foods in Brazil.

PubMed

Arisseto, A P; Vicente, E; Furlani, R P Z; Ueno, M S; Pereira, A L D; Toledo, M C F

2012-01-01

Selected commercial processed foods available in the Brazilian market (306 samples) were analysed for furan content using a validated gas chromatography-mass spectrometry method preceded by headspace solid phase micro-extraction (HS-SPME-GC/MS). Canned and jarred foods, including vegetable, meat, fruit and sweet products, showed levels up to 32.8 µg kg⁻¹, with the highest concentrations observed in vegetables and meats. For coffee, furan content ranged from 253.0 to 5021.4 µg kg⁻¹ in the roasted ground coffee and from not detected to 156.6 µg kg⁻¹ in the beverage. For sauces, levels up to 138.1 µg kg⁻¹ were found. In cereal-based products, the highest concentrations (up to 191.3 µg kg⁻¹) were observed in breakfast cereal (corn flakes), cracker (cream crackers) and biscuit (wafer). In general, these results are comparable with those reported in other countries and will be useful for a preliminary estimate of the furan dietary intake in Brazil.

Irreversible endo-selective diels-alder reactions of substituted alkoxyfurans: a general synthesis of endo-cantharimides.

PubMed

Foster, Robert W; Benhamou, Laure; Porter, Michael J; Bučar, Dejan-Krešimir; Hailes, Helen C; Tame, Christopher J; Sheppard, Tom D

2015-04-13

The [4+2] cycloaddition of 3-alkoxyfurans with N-substituted maleimides provides the first general route for preparing endo-cantharimides. Unlike the corresponding reaction with 3H furans, the reaction can tolerate a broad range of 2-substitued furans including alkyl, aromatic, and heteroaromatic groups. The cycloaddition products were converted into a range of cantharimide products with promising lead-like properties for medicinal chemistry programs. Furthermore, the electron-rich furans are shown to react with a variety of alternative dienophiles to generate 7-oxabicyclo[2.2.1]heptane derivatives under mild conditions. DFT calculations have been performed to rationalize the activation effect of the 3-alkoxy group on a furan Diels-Alder reaction. © 2015 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

An interpenetrating HA/G/CS biomimic hydrogel via Diels-Alder click chemistry for cartilage tissue engineering.

PubMed

Yu, Feng; Cao, Xiaodong; Zeng, Lei; Zhang, Qing; Chen, Xiaofeng

2013-08-14

In order to mimic the natural cartilage extracellular matrix, a novel biological degradable interpenetrating network hydrogel was synthesized from the gelatin (G), hyaluronic acid (HA) and chondroitin sulfate (CS) by Diels-Alder "click" chemistry. HA was modified with furylamine and G was modified with furancarboxylic acid respectively. (1)H NMR spectra and elemental analysis showed that the substitution degrees of HA-furan and G-furan were 71.5% and 44.5%. Then the hydrogels were finally synthesized by cross-linking furan-modified HA and G derivatives with dimaleimide poly(ethylene glycol) (MAL-PEG-MAL). The mechanical and degradation properties of the hydrogels could be tuned simply through varying the molar ratio between furan and maleimide. Rheological, mechanical and degradation studies demonstrated that the Diels-Alder "click" chemistry is an efficient method for preparing high performance biological interpenetrating hydrogels. This biomimic hydrogel with improved mechanical properties could have great potential applications in cartilage tissue engineering. Copyright © 2013 Elsevier Ltd. All rights reserved.

Removal of furan and phenolic compounds from simulated biomass hydrolysates by batch adsorption and continuous fixed-bed column adsorption methods.

PubMed

Lee, Sang Cheol; Park, Sunkyu

2016-09-01

It has been proposed to remove all potential inhibitors and sulfuric acid in biomass hydrolysates generated from dilute-acid pretreatment of biomass, based on three steps of sugar purification process. This study focused on its first step in which furan and phenolic compounds were selectively removed from the simulated hydrolysates using activated charcoal. Batch adsorption experiments demonstrated that the affinity of activated charcoal for each component was highest in the order of vanillic acid, 4-hydroxybenzoic acid, furfural, acetic acid, sulfuric acid, and xylose. The affinity of activated charcoal for furan and phenolic compounds proved to be significantly higher than that of the other three components. Four separation strategies were conducted with a combination of batch adsorption and continuous fixed-bed column adsorption methods. It was observed that xylose loss was negligible with near complete removal of furan and phenolic compounds, when at least one fixed-bed column adsorption was implemented in the strategy. Copyright © 2016 Elsevier Ltd. All rights reserved.

Substituent effects on furan-phenylene copolymer for photovoltaic improvement: A density functional study

NASA Astrophysics Data System (ADS)

Janprapa, Nuttaporn; Vchirawongkwin, Viwat; Kritayakornupong, Chinapong

2018-06-01

The structural, electronic and photovoltaic properties of furan-phenylene copolymer ((Fu-co-Ph)4) and its derivatives were evaluated using density functional theory (DFT) and time-dependent density functional theory (TD-DFT). The calculated band gaps of pristine furan and phenylene are in good agreement with the available experimental data. The lower band gap value of 2.72 eV was obtained from -NO2 and -NHCH3 substituents, leading to broader solar absorption range. With respected to the reorganization energy, -OCH3, -NHCH3, -OH, -SCH3, -CH3, -CF3, -NO2, and -F substituted (Fu-co-Ph)4 structures were classified as better electron donor materials. For combination with PC61BM, -NO2, -CN, -CF3 and -F functionalized copolymers demonstrated significantly higher open circuit voltage (Voc) values ranging from 1.07 to 2.10 eV. Our results revealed that electron withdrawing group substitution on furan-phenylene copolymers was an effective way for improving electronic and optical properties of donor materials used in photovoltaic applications.

2-Arylbenzo[b]furan derivatives as potent human lipoxygenase inhibitors.

PubMed

Lang, Li; Dong, Ningning; Wu, Deyan; Yao, Xue; Lu, Weiqiang; Zhang, Chen; Ouyang, Ping; Zhu, Jin; Tang, Yun; Wang, Wei; Li, Jian; Huang, Jin

2016-01-01

Human lipoxygenases (LOXs) have been emerging as effective therapeutic targets for inflammatory diseases. In this study, we found that four natural 2-arylbenzo[b]furan derivatives isolated from Artocarpus heterophyllus exhibited potent inhibitory activities against human LOXs, including moracin C (1), artoindonesianin B-1 (2), moracin D (3), moracin M (4). In our in vitro experiments, compound 1 was identified as the most potent LOX inhibitor and the moderate subtype selective inhibitor of 12-LOX. Compounds 1 and 2 act as competitive inhibitors of LOXs. Moreover, 1 significantly inhibits LTB4 production and chemotactic capacity of neutrophils, and is capable of protecting vascular barrier from plasma leakage in vivo. In addition, the preliminary structure-activity relationship analysis was performed based on the above four naturally occurring (1-4) and six additional synthetic 2-arylbenzo[b]furan derivatives. Taken together, these 2-arylbenzo[b]furan derivatives, as LOXs inhibitors, could represent valuable leads for the future development of therapeutic agents for inflammatory diseases.

40 CFR Table 1 to Subpart Bbbb of... - Model Rule-Compliance Schedules and Increments of Progress

Code of Federal Regulations, 2010 CFR

2010-07-01

... modification after June 26, 1987, comply with the dioxins/furans and mercury limits by the later of two dates... the dioxins/furans limits must be achieved no later than December 6, 2005, even if the date one year...

Combustion chemistry and flame structure of furan group biofuels using molecular-beam mass spectrometry and gas chromatography – Part III: 2,5-Dimethylfuran

PubMed Central

Togbé, Casimir; Tran, Luc-Sy; Liu, Dong; Felsmann, Daniel; Oßwald, Patrick; Glaude, Pierre-Alexandre; Sirjean, Baptiste; Fournet, René; Battin-Leclerc, Frédérique; Kohse-Höinghaus, Katharina

2013-01-01

This work is the third part of a study focusing on the combustion chemistry and flame structure of furan and selected alkylated derivatives, i.e. furan in Part I, 2-methylfuran (MF) in Part II, and 2,5-dimethylfuran (DMF) in the present work. Two premixed low-pressure (20 and 40 mbar) flat argon-diluted (50%) flames of DMF were studied with electron-ionization molecular-beam mass spectrometry (EI-MBMS) and gas chromatography (GC) under two equivalence ratios (φ=1.0 and 1.7). Mole fractions of reactants, products, and stable and radical intermediates were measured as a function of the distance to the burner. Kinetic modeling was performed using a reaction mechanism that was further developed in the present series, including Part I and Part II. A reasonable agreement between the present experimental results and the simulation is observed. The main reaction pathways of DMF consumption were derived from a reaction flow analysis. Also, a comparison of the key features for the three flames is presented, as well as a comparison between these flames of furanic compounds and those of other fuels. An a priori surprising ability of DMF to form soot precursors (e.g. 1,3-cyclopentadiene or benzene) compared to less substituted furans and to other fuels has been experimentally observed and is well explained in the model. PMID:24518851

Combustion chemistry and flame structure of furan group biofuels using molecular-beam mass spectrometry and gas chromatography - Part III: 2,5-Dimethylfuran.

PubMed

Togbé, Casimir; Tran, Luc-Sy; Liu, Dong; Felsmann, Daniel; Oßwald, Patrick; Glaude, Pierre-Alexandre; Sirjean, Baptiste; Fournet, René; Battin-Leclerc, Frédérique; Kohse-Höinghaus, Katharina

2014-03-01

This work is the third part of a study focusing on the combustion chemistry and flame structure of furan and selected alkylated derivatives, i.e. furan in Part I, 2-methylfuran (MF) in Part II, and 2,5-dimethylfuran (DMF) in the present work. Two premixed low-pressure (20 and 40 mbar) flat argon-diluted (50%) flames of DMF were studied with electron-ionization molecular-beam mass spectrometry (EI-MBMS) and gas chromatography (GC) under two equivalence ratios (φ=1.0 and 1.7). Mole fractions of reactants, products, and stable and radical intermediates were measured as a function of the distance to the burner. Kinetic modeling was performed using a reaction mechanism that was further developed in the present series, including Part I and Part II. A reasonable agreement between the present experimental results and the simulation is observed. The main reaction pathways of DMF consumption were derived from a reaction flow analysis. Also, a comparison of the key features for the three flames is presented, as well as a comparison between these flames of furanic compounds and those of other fuels. An a priori surprising ability of DMF to form soot precursors (e.g. 1,3-cyclopentadiene or benzene) compared to less substituted furans and to other fuels has been experimentally observed and is well explained in the model.

CHLOROBENZENES, CHLOROPHENOLS, PHAS AND LOW CHLORINATED DIOXIN/FURAN POST-BOILER TOXICITY INDICATORS IN MUNICIPAL SOLID WASTE INCINERATORS

EPA Science Inventory

Research has sought indicator compounds for fast and less costly predictive monitoring of polychlorinated dibenzo-p-dioxin and furans, PCDD/F, toxic equivalent concentrations or TEQs. Studies have shown chlorobenzenes and chlorophenols had a good correlation with TEQ, suggesting ...

CHLOROBENZENES, CHLOROPHENOLS, PAHS AND LOW CHLORINATED DIOXIN/FURAN AS POST-BOILER TOXICITY INDICATORS IN MUNICIPAL SOLID WASTE INCINERATORS

EPA Science Inventory

Numerous research studies have been conducted to establish indicator compounds for fast and less costly predictive monitoring of polychlorinated dibenzo-p-dioxin and furan (PCDD/F) toxic equivalent concentrations (TEQs). Many studies have shown that chlorobenzenes and chlorophen...

Novel biobased photo-crosslinked polymer networks prepared from vegetable oil and 2,5-furan diacrylate

USDA-ARS?s Scientific Manuscript database

Novel biobased crosslinked polymer networks were prepared from vegetable oil with 2,5-furan diacrylate as a difunctional stiffener through UV photopolymerization, and the mechanical properties of the resulting films were evaluated. The vegetable oil raw materials used were acrylated epoxidized soybe...

Formation of furan fatty alkyl esters from their bis-epoxide fatty esters

USDA-ARS?s Scientific Manuscript database

Reactions of epoxidized alkyl soyate with four different alcohols: ethanol, isopropyl alcohol, 2-ethylhexanol, and benzyl alcohol were investigated in the presence of Bronsted acid catalyst. Products not reported in prior studies of similar reactions were found. These were furan fatty acid alkyl est...

Formation of furan fatty alkyl esters from their bis-epoxide fatty esters

USDA-ARS?s Scientific Manuscript database

Reactions of epoxidized alkyl soyate with four different alcohols: ethanol, isopropyl alcohol, 2-ethylhexanol, benzyl alcohol, in the presence of Bronsted acid catalyst, were investigated. Products that were not reported in prior studies of similar reactions were found. These were furan fatty acid a...

Synthesis and PGE(2) production inhibition of 1H-furan-2,5-dione and 1H-pyrrole-2,5-dione derivatives.

PubMed

Moon, Jong Taik; Jeon, Ji Young; Park, Hang Ah; Noh, Young-Soo; Lee, Kyung-Tae; Kim, Jungahn; Choo, Dong Joon; Lee, Jae Yeol

2010-01-15

3,4-Diphenyl-substituted 1H-furan-2,5-dione and 1H-pyrrole-2,5-dione derivatives were synthesized and evaluated for the inhibitory activities on LPS-induced PGE(2) production in RAW 264.7 macrophage cells. Both 1H-furan-2,5-dione and 1H-pyrrole-2,5-dione rings as main scaffolds were easily obtained using one of three synthetic methods. Among the compounds investigated, 1H-3-(4-sulfamoylphenyl)-4-phenyl-pyrrole-2,5-dione (6l) showed a strong inhibitory activity (IC(50)=0.61microM) of PGE(2) production. Copyright 2009 Elsevier Ltd. All rights reserved.

Production of a novel antioxidant furan fatty acid from 7,10-dihydroxy-8(E)-octadecenoic acid

USDA-ARS?s Scientific Manuscript database

Furan fatty acids (F-acids) have gained attention since they are known to play important roles in a variety of biological systems. Specifically F-acids are known to have strong antioxidant activity. Although widely distributed in most biological systems, F-acids are trace components and their biosyn...

40 CFR 62.15355 - What must I include in the semiannual out-of-compliance reports?

Code of Federal Regulations, 2010 CFR

2010-07-01

... this subpart as applicable for dioxins/furans, cadmium, lead, mercury, particulate matter, opacity... control dioxins/furans or mercury emissions, include two items: (1) Documentation of all dates when the 8...) is less than the highest carbon feed rate established during the most recent mercury and dioxins...

One-step production of a biologically active novel furan fatty acid from 7,10-dihydroxy-8(E)-octadecenoic acid

USDA-ARS?s Scientific Manuscript database

Furan fatty acids (F-acids) gain special attentions since they are known to play important roles in biological systems including humans. Specifically F-acids are known to have strong antioxidant activity like radical scavenging activity. Although widely distributed in most biological systems, F-ac...

Toxicity comparison of chlorinated and brominated dibenzo-p-dioxins and dibenzofurans in industrial source samples by HRGC/HRMS and enzyme immunoassay

EPA Science Inventory

Limited information is available on the applicability of polychlorinated dibenzo-p-dioxin/furan (PCDD/F) toxicity assays to their brominated counterparts: polybrominated dibenzo-p-dixoins/furans (PBDDs/Fs). We estimated the toxicity of mixtures of chlorinated, brominated, and mi...

Synchrotron Photoionization Study of Furan and 2-Methylfuran Reactions with Methylidyne Radical (CH) at 298 K.

PubMed

Carrasco, Erica; Smith, Kenneth J; Meloni, Giovanni

2018-01-11

The reactions of furan and 2-methylfuran with methylidyne CH (X 2 Π) radical were investigated at 298 K using synchrotron radiation produced at the Advanced Light Source of the Lawrence Berkeley National Laboratory. Reaction products were observed by multiplexed photoionization mass spectrometry and characterized based on their photoionization spectra and kinetic time traces. Primary products observed in furan + CH are 2,4-cyclopentadien-1-one (m/z = 80), 2-penten-4-ynal (m/z = 80), and vinylacetylene (m/z = 52). From 2-methylfuran + CH, 2-4-cyclopentadien-1-carbaldehyde (m/z = 94), 2,3,4-hexatrienal (m/z = 94), 1,3 cyclopentadiene (m/z = 66), 3-penten-1-yne (Z) (m/z = 66), and vinylacetylene (m/z = 52) are the primary products observed. Using potential energy surface scans, thermodynamically favorable reaction pathways are proposed. CH addition to the π-bonds in furan and 2-methylfuran rings was found to be the entrance channel that led to formation of all identified primary products. Both reactions follow patterns of H loss and CHO loss, as well as formation of cyclic and acyclic isomers.

Wildlife in a chemical world

USGS Publications Warehouse

Melancon, M.J.; Russell, J.S.; Estenik, J.F.; Fisher, S.W.; Dabrowska, H.

2000-01-01

Snapping turtles were collected by the Ohio State EPA from six locations in Ohio believed to have different contaminant concentrations. Previously we reported significant correlations among four hepatic microsomal dealkylases and CYP1A in these turtles. Herein we compare ethoxyresorufin-O-dealkylase (EROD) and methoxyROD (MROD) to tissue contaminant concentrations. For Fifty-four of these turtles, muscle, fat body and liver tissues were assessed for PCBs and 20 organochlorine analytes and hepatic microsomal dealkylases. Of the contaminants analyzed, only DDE, dieldrin, oxychlordane, trans-nonachlor and PCB 1260 were detected in >25% of each sample type. When EROD and MROD activities were compared to tissue values for these contaminants, they were found to correlate significantly only to DDE, dieldrin and trans-nonachlor. For an 18 female subset of these turtles, serum PCBs and organochlorine pesticides, egg, fat body and liver dioxins and furans, and hepatic microsomal dealkylases were assessed. EROD and MROD both correlated significantly to serum PCB 105, PCB 138 and DDE, and to egg total PCBs. EROD and MROD did not correlate significantly with liver dioxins and furans, but there were significant correlations between EROD and egg and fat body dioxins and furans, and MROD and fat body dioxins and furans. It is expected that CYP1A-type inducers such as certain PCBs, and halogenated dioxins and furans, but not organochlorine pesticides, would be inducers in turtles. Presumably the correlation of monooxygenase with organochlorine pesticides is fortuitous, and toxic equivalencies are being calculated using a number of systems.

Preliminary assessment of the risk linked to furan ingestion by babies consuming only ready-to-eat food.

PubMed

Scholl, Georges; Humblet, Marie-France; Scippo, Marie-Louise; De Pauw, Edwin; Eppe, Gauthier; Saegerman, Claude

2013-01-01

The risk linked to furan ingestion has been assessed in previous papers for Belgian adults and children. The present paper focuses on infants consuming only ready-to-eat baby food. As there is no Belgian baby dietary database, the furan exposure assessment was carried out by using an Italian infant consumption database and Belgian contamination data. The estimated daily intake (EDI) was calculated according to a deterministic methodology. It involved 42 commercially available ready-to-eat baby food and 36 baby consumption records. The mean EDI was 1460 ng*(kg(bw)*day)⁻¹ which is 3.8 times higher than the 381 ng*(kg(bw)*day)⁻¹ reported for Belgian adults, and 3.5 times higher than the 419 ng*(kg(bw)*day)⁻¹ measured for Belgian children. To assess and characterise the risk for babies' exposure, the margin of exposure (MoE) was calculated. It highlighted that 74% of infants have a MoE < 1000, with a minimum of 140. However, these are only preliminary results as they were calculated from a very small dataset and the infant cytochrome P450 activity is significantly different compared with the adult's. Therefore, the risk linked to furan ingestion by babies should be assessed in a different manner. To this end, additional data regarding a baby diet as well as a better understanding of furan toxicity for babies are needed to characterise more accurately the risk for infants.

Detailed exposure assessment of dietary furan for infants consuming commercially jarred complementary food based on data from the DONALD study.

PubMed

Lachenmeier, Dirk W; Maser, Elena; Kuballa, Thomas; Reusch, Helmut; Kersting, Mathilde; Alexy, Ute

2012-07-01

Furan is a possible human carcinogen regularly occurring in commercially jarred complementary foods. This paper will provide a detailed exposure assessment for babies consuming these foods considering different intake scenarios. The occurrence data on furan in complementary foods were based on our own headspace-gas chromatography/mass spectrometry (HS-GC/MS) analytical results (n = 286). The average furan content in meals and menus was between 20 and 30 µg kg(-1), which is in excellent agreement with results from other European countries. Using measured food consumption data from the Dortmund Nutritional and Anthropometric Longitudinally Designed (DONALD) study, the average exposures for consumers of commercially jarred foods ranged between 182 and 688 ng kg(-1) bw day(-1), with a worst case scenario for P95 consumers ranging between 351 and 1066 ng kg(-1) bw day(-1). The exposure data were then used to characterize risk using the margin of exposure method based on a benchmark dose lower confidence limit for a 10% response (BMDL10) of 1.28 mg kg(-1) bw day(-1) for hepatocellular tumours in rats. The margin of exposures (MOEs) were below the threshold of 10 000, which is often used to define public health risks, in all scenarios, ranging between 7022 and 1861 for average consumers and between 3642 and 1200 for the P95 consumers. Mitigative measures to avoid furan in complementary foods should be of high priority for risk management. © 2010 Blackwell Publishing Ltd.

Gold(III) chloride catalyzed synthesis of chiral substituted 3-formyl furans from carbohydrates: application in the synthesis of 1,5-dicarbonyl derivatives and furo[3,2-c]pyridine.

PubMed

Mal, Kanchan; Sharma, Abhinandan; Das, Indrajit

2014-09-08

This report describes a gold(III)-catalyzed efficient general route to densely substituted chiral 3-formyl furans under extremely mild conditions from suitably protected 5-(1-alkynyl)-2,3-dihydropyran-4-one using H2 O as a nucleophile. The reaction proceeds through the initial formation of an activated alkyne-gold(III) complex intermediate, followed by either a domino nucleophilic attack/anti-endo-dig cyclization, or the formation of a cyclic oxonium ion with subsequent attack by H2 O. To confirm the proposed mechanistic pathway, we employed MeOH as a nucleophile instead of H2 O to result in a substituted furo[3,2-c]pyran derivative, as anticipated. The similar furo[3,2-c]pyran skeleton with a hybrid carbohydrate-furan derivative has also been achieved through pyridinium dichromate (PDC) oxidation of a substituted chiral 3-formyl furan. The corresponding protected 5-(1-alkynyl)-2,3-dihydropyran-4-one can be synthesized from the monosaccharides (both hexoses and pentose) following oxidation, iodination, and Sonogashira coupling sequences. Furthermore, to demonstrate the potentiality of chiral 3-formyl furan derivatives, a TiBr4 -catalyzed reaction of these derivatives has been shown to offer efficient access to 1,5-dicarbonyl compounds, which on treatment with NH4 OAc in slightly acidic conditions afforded substituted furo[3,2-c]pyridine. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A review of dioxins/furans and methyl mercury in fish from the Penobscot river, located near Lincoln, Maine.

PubMed

Williams, Robert L; Cseh, Larry

2007-04-01

The Agency for Toxic Substances and Disease Registry (ATSDR) was requested to review the analytical results of tissue samples from fish caught in the Penobscot river in Maine, calculate fish consumption limits and provide a public health opinion regarding the health implications associated with eating the contaminated fish. Fish consumption limits were calculated to provide guidance on the amount of fish that a person may eat monthly that would probably not pose a public health threat. Earlier, in 1987, the Maine Bureau of Health (BOH) issued a fish consumption advisory for portions of the Penobscot river to protect the public from exposures to dioxins/furans and methyl mercury-contaminated fish. From 1988 to 2003 the state of Maine conducted fish surveys at four locations along the Penobscot river to monitor the levels of dioxins/furans and methyl mercury contamination. In 2005, ATSDR reviewed the sampling results for two fish species (i.e., bottom feeders and predators) collected from the Penobscot river that revealed various levels of dioxins/furans and methyl mercury. The United States Environmental Protection Agency's (US EPA) guidance for evaluating potential health threats associated with contaminated fish recommends that a minimum of two target species be sampled including one predatory and one bottom feeding species. Target species are chosen to meet the following criteria: (1) known to accumulate high concentrations of target contaminants in their tissues; (2) normally populate the freshwater system being studied; (3) are routinely caught and consumed by anglers; (4) nonmigratory; (5) pollutant-tolerant; (6) easily identified; (7) abundant and easy to collect and (8) of sufficient size to provide adequate tissue samples for analyses of contaminants (US EPA, 2000). The analytical results of these fish tissue samples appear to indicate that toxic equivalency quotients concentrations of dioxins/furans have slightly decreased since 1988. In contrast, fish tissue levels of methyl mercury appear to have increased slightly since 1988. Dioxins/furans and methyl mercury levels detected in fish tissue samples caught in the Penobscot river located near Lincoln, Maine, may continue to pose a public health hazard to persons who consume the fish daily, depending on the amount consumed. The ATSDR concurred with Maine BOH's fish advisory for dioxins/furans and methyl mercury, that is, currently in place for portions of the Penobscot river near Lincoln.

THE CONCENTRATION AND DISTRIBUTION OF 2,3,7,8-DIBENZO-P-DIOXINS / - FURANS IN CHICKENS

EPA Science Inventory

The concentrations of 2,3,7,8-Cl substituted dibenzo-p-dioxins/-furans (PCDDs/PCDFs) were determined in the edible tissues of whole chicken fryers and compared with the values found in their abdominal fat. The values are presented both on a whole weight basis and on a lipid-adju...

A high temperature and atmospheric pressure experimental and detailed chemical kinetic modelling study of 2-methyl furan oxidation

PubMed Central

Somers, Kieran P.; Simmie, John M.; Gillespie, Fiona; Burke, Ultan; Connolly, Jessica; Metcalfe, Wayne K.; Battin-Leclerc, Frédérique; Dirrenberger, Patricia; Herbinet, Olivier; Glaude, Pierre-Alexandre; Curran, Henry J.

2013-01-01

An experimental ignition delay time study for the promising biofuel 2-methyl furan (2MF) was performed at equivalence ratios of 0.5, 1.0 and 2.0 for mixtures of 1% fuel in argon in the temperature range 1200–1800 K at atmospheric pressure. Laminar burning velocities were determined using the heat-flux method for mixtures of 2MF in air at equivalence ratios of 0.55–1.65, initial temperatures of 298–398 K and atmospheric pressure. A detailed chemical kinetic mechanism consisting of 2059 reactions and 391 species has been constructed to describe the oxidation of 2MF and is used to simulate experiment. Accurate reproduction of the experimental data has been obtained over all conditions with the developed mechanism. Rate of production and sensitivity analyses have been carried out to identify important consumption pathways of the fuel and key kinetic parameters under these conditions. The reactions of hydrogen atom with the fuel are highlighted as important under all experimental conditions studied, with abstraction by the hydrogen atom promoting reactivity and hydrogen atom addition to the furan ring inhibiting reactivity. This work, to the authors knowledge, is the first to combine theoretical and experimental work to describe the oxidation of any of the alkylated furans. The mechanism developed herein to describe 2MF combustion should also function as a sub-mechanism to describe the oxidation of 2,5-dimethyl furan whilst also providing key insights into the oxidation of this similar biofuel candidate. PMID:23814505

Dioxin inhalation doses from wood combustion in indoor cookfires

NASA Astrophysics Data System (ADS)

Northcross, Amanda L.; Katharine Hammond, S.; Canuz, Eduardo; Smith, Kirk R.

2012-03-01

Approximately 3 billion people worldwide rely on solid biomass fuels for household cooking and space heating, and approximately 50-60% use wood, often indoors in poorly ventilated situations. Daily exposures to high concentrations of smoke from cookstoves inside kitchens create large smoke exposures for women cooks and their small children. The smoke from burning the wood fuel contains hundred of toxic compounds, including dioxins and furans some of the most toxic compounds known to science. Health effects from exposure to dioxins include reproductive and developmental problems, damage the immune system, interference with hormones and also cause cancer. This study measured concentrations of dioxins and furans in a typical Guatemalan village home during open cookfires. Measured concentrations averaged 0.32 ± 0.07 ng m-3 over 31 fires. A Monte Carlo simulation was conducted using parameter estimates based on 8 years of research experience in the study area. The estimated total daily intake of 17 particle phase dioxin and furans for women, a 5-year-old child and a 6-month-old infant were 1.2 (S.D. = 0.4), 1.7 (S.D. = 0.7) and 2.0 (S.D. = 0.5) respectively. The 46% of babies have and estimated total daily intake (TDI) which exceed the WHO TDI guideline for dioxins and furans, 3% of women and 26% of 5-year-old children based solely inhalation of particle phase dioxins in woodsmoke from an open cooking fire. These values maybe underestimates, as they did not include gas phase concentrations or ingestion of dioxins and furans through food, which is the largest route of exposure in the developed world.

Determination of relative assay response factors for toxic chlorinated and bromiated dioxins/furans using an enyme immunoassay (EIA) and a chemically-activated luciferase gene expression cell bioassay (CALUX)

EPA Science Inventory

Determination of dioxin-like activity requires knowledge of both the concentration and toxicity to evaluate the risk of adverse human health and environmental effects. The dioxin-like response of several polybrominated dibenzo-p-dioxins/furans (PBDDs/Fs) and polybrominated/chlori...

Green oxidations of furans--initiated by molecular oxygen--that give key natural product motifs.

PubMed

Montagnon, Tamsyn; Noutsias, Dimitris; Alexopoulou, Ioanna; Tofi, Maria; Vassilikogiannakis, Georgios

2011-04-07

In this article, we explore how changes in the positioning of pendant hydroxyl functionalities in the photooxygenation substrate dramatically alter the course of furan oxidations that are initiated by singlet oxygen; and, how these different reactivities can be harnessed through cascade reaction sequences to access, rapidly and effectively, a broad range of important natural product motifs.

A Furan-Thiophene-Based Quinoidal Compound: A New Class of Solution-Processable High-Performance n-Type Organic Semiconductor.

PubMed

Xiong, Yu; Tao, Jingwei; Wang, Ruihao; Qiao, Xiaolan; Yang, Xiaodi; Wang, Deliang; Wu, Hongzhuo; Li, Hongxiang

2016-07-01

The furan-thiophene-based quinoidal organic semiconductor, TFT-CN, is designed and synthesized. TFT-CN displays a high electron mobility of 7.7 cm(2) V(-1) s(-1) , two orders of magnitude higher than the corresponding thiophene-based derivative. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

40 CFR 63.9915 - What test methods and other procedures must I use to demonstrate initial compliance with dioxin...

Code of Federal Regulations, 2010 CFR

2010-07-01

... must I use to demonstrate initial compliance with dioxin/furan emission limits? 63.9915 Section 63.9915....9915 What test methods and other procedures must I use to demonstrate initial compliance with dioxin... limit for dioxins/furans in Table 1 to this subpart, you must follow the test methods and procedures...

40 CFR Table 2b to Subpart Ce of... - Emissions Limits for Small HMIWI Which Meet the Criteria Under § 60.33e(b)(2)

Code of Federal Regulations, 2010 CFR

2010-07-01

... sample time per run) EPA Reference Method 10 or 10B of appendix A-4 of part 60. Dioxins/furans ng/dscm total dioxins/furans (gr/109 dscf) or ng/dscm TEQ (gr/109 dscf) 240 (100) or 5.1 (2.2) 3-run average (4...

40 CFR Table 2a to Subpart Ce of... - Emissions Limits for Small HMIWI Which Meet the Criteria Under § 60.33e(b)(1)

Code of Federal Regulations, 2010 CFR

2010-07-01

... sample time per run) EPA Reference Method 10 or 10B of appendix A-4 of part 60. Dioxins/furans ng/dscm total dioxins/furans (gr/109 dscf) or ng/dscm TEQ (gr/109 dscf) 800 (350) or 15 (6.6) 3-run average (4...

One-Pot Conversion of Carbohydrates into Furan Derivatives via Furfural and 5-Hydroxylmethylfurfural as Intermediates.

PubMed

Liu, Bing; Zhang, Zehui

2016-08-23

Recently, there has been growing interest in the transformation of renewable biomass into value-added fuels and chemicals. The catalytic conversion of naturally abundant carbohydrates can generate two-important furan chemicals: 5-hydroxymethylfurfural (HMF) from C6 carbohydrates and furfural from C5 carbohydrates. Both HMF and furfural have received great interest as precursors in the synthesis of commodity chemicals and liquid fuels. In recent years, a trend has emerged to integrate sequential catalytic processes involving multistep reactions for the direct one-pot transformation of carbohydrates into the aimed fuels and chemicals. One-pot reactions have remarkably unique and environmentally friendly benefits, including the fact that isolation and purification of intermediate compounds can be avoided. Herein, the present article aims to review recent advances in the one-pot conversion of carbohydrates into furan derivatives via furfural and HMF as intermediates. Special attention will be paid to the catalytic systems, mechanistic insight, reaction pathways, and catalyst stability. It is expected that this review will guide researchers to develop effective catalytic systems for the one-pot transformation of carbohydrates into furan derivatives. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Estimation of furan contamination across the Belgian food chain.

PubMed

Scholl, G; Scippo, M-L; De Pauw, E; Eppe, G; Saegerman, C

2012-01-01

This paper provides an estimate of the furan content of Belgian foods. The objective of the study was to achieve the best food chain coverage with a restricted number of samples (n = 496). The geographic distribution, different market chains and labels, and consumption frequencies were taken into account in the construction of the sampling plan. Weighting factors such as contamination levels, consumption frequency and the diversity of food items were applied to set up the model. The very low detection capabilities (CC(β)) of the analytical methods used (sub-ppb) allowed reporting of 78.2% of the overall dataset above CC(β) and, in particular, 96.7% for the baby food category. The highest furan levels were found in powdered roasted bean coffee (1912 µg kg(-1)) with a mean of 756 µg kg(-1) for this category. Prepared meat, pasta and rice, breakfast cereals, soups, and baby food also showed high mean furan contents ranging from 16 to 43 µg kg(-1). Comparisons with contamination surveys carried out in other countries pointed out differences for the same food group and therefore contamination levels are related to the geographical origin of food items.

Predictors of Serum Dioxin, Furan and PCB Concentrations among Women from Chapaevsk, Russia

PubMed Central

Humblet, Olivier; Williams, Paige L.; Korrick, Susan A.; Sergeyev, Oleg; Emond, Claude; Birnbaum, Linda S.; Burns, Jane S.; Altshul, Larisa; Patterson, Donald G.; Turner, Wayman E.; Lee, Mary M.; Revich, Boris; Hauser, Russ

2011-01-01

INTRODUCTION Dioxins, furans and polychlorinated biphenyls (PCBs) are persistent and bioaccumulative toxic chemicals that are ubiquitous in the environment. We assessed predictors of their serum concentrations among women living in a Russian town contaminated by past industrial activity. METHODS Blood samples from 446 mothers aged 23–52 years were collected between 2003–2005 as part of the Russian Children’s Study. Serum dioxin, furan and PCB concentrations were quantified using high-resolution gas chromatography-mass spectrometry. Potential determinants of exposure were collected through interviews. Multivariate linear regression models were used to identify predictors of serum concentrations and toxic equivalencies (TEQs). RESULTS AND DISCUSSION The median total PCB concentrations and total TEQs were 260 ng/g lipid and 25 pg TEQ/g lipid, respectively. In multivariate analyses, both total PCB concentrations and total TEQs increased significantly with age, residential proximity to a local chemical plant, duration of local farming, and consumption of local beef. Both decreased with longer breastfeeding, recent increases in body mass index, and later blood draw date. These demographic and lifestyle predictors showed generally similar associations with the various measures of serum dioxins, furans, and PCBs. PMID:20578718

Covalent modification of cytochrome c by reactive metabolites of furan.

PubMed

Phillips, Martin B; Sullivan, Mathilde M; Villalta, Peter W; Peterson, Lisa A

2014-01-21

Metabolism of the hepatotoxicant furan leads to protein adduct formation in the target organ. The initial bioactivation step involves cytochrome P450-catalyzed oxidation of furan, generating cis-2-butene-1,4-dial (BDA). BDA reacts with lysine to form pyrrolin-2-one adducts. Metabolic studies indicate that BDA also reacts with glutathione (GSH) to generate 2-(S-glutathionyl)butanedial (GSH-BDA), which then reacts with lysine to form GSH-BDA-lysine cross-links. To explore the relative reactivity of these two reactive intermediates, cytochrome c was reacted with BDA in the presence and absence of GSH. As judged by MALDI-TOF mass spectrometry, BDA reacts extensively with cytochrome c to form adducts that add 66 Da to the protein, consistent with the formation of pyrrolinone adducts. Addition of GSH to the reaction mixture reduced the overall extent of adduct formation. The mass of the adducted protein was shifted by 355 Da as expected for GSH-BDA-protein cross-link formation. LC-MS/MS analysis of the tryptic digests of the alkylated protein indicated that the majority of adducts occurred on lysine residues, with BDA reacting less selectively than GSH-BDA. Both types of adducts may contribute to the toxic effects of furan.

Covalent Modification of Cytochrome C by Reactive Metabolites of Furan

PubMed Central

Phillips, Martin B.; Sullivan, Mathilde M.; Villalta, Peter W.; Peterson, Lisa A.

2014-01-01

Metabolism of the hepatotoxicant furan leads to protein adduct formation in the target organ. The initial bioactivation step involves cytochrome P450-catalyzed oxidation of furan, generating cis-2-butene-1,4-dial (BDA). BDA reacts with lysine to form pyrrolin-2-one adducts. Metabolic studies indicate that BDA also reacts with glutathione (GSH) to generate 2-(S-glutathionyl)butanedial (GSH-BDA), which then reacts with lysine to form GSH-BDA-lysine cross-links. To explore the relative reactivity of these two reactive intermediates, cytochrome c was reacted with BDA in the presence and absence of GSH. As judged by MALDI-TOF mass spectrometry, BDA reacts extensively with cytochrome c to form adducts that add 66 Da to the protein, consistent with the formation of pyrrolinone adducts. Addition of GSH to the reaction mixture reduced the overall extent of adduct formation. The mass of the adducted protein was shifted by 355 Da as expected for GSH-BDA-protein cross-link formation. LC-MS/MS analysis of the tryptic digests of the alkylated protein indicated that the majority of adducts occurred on lysine residues, with BDA reacting less selectively than GSH-BDA. Both types of adducts may contribute to the toxic effects of furan. PMID:24364757

Electrically conductive alternating copolymers

DOEpatents

Aldissi, M.; Jorgensen, B.S.

1987-08-31

Polymers which are soluble in common organic solvents and are electrically conductive, but which also may be synthesized in such a manner that they become nonconductive. Negative ions from the electrolyte used in the electrochemical synthesis of a polymer are incorporated into the polymer during the synthesis and serve as a dopant. A further electrochemical step may be utilized to cause the polymer to be conductive. The monomer repeat unit is comprised of two rings, a pyrrole molecule joined to a thienyl group, or a furyl group, or a phenyl group. The individual groups of the polymers are arranged in an alternating manner. For example, the backbone arrangement of poly(furylpyrrole) is -furan-pyrrole-furan-pyrrole- furan-pyrrole. An alkyl group or phenyl group may be substituted for either or both of the hydrogen atoms of the pyrrole ring.

Tunable Oleo-Furan Surfactants by Acylation of Renewable Furans

DOE PAGES

Park, Dae Sung; Joseph, Kristeen E.; Koehle, Maura; ...

2016-10-19

One important advance in fluid surface control was the amphiphilic surfactant composed of coupled molecular structures (i.e., hydrophilic and hydrophobic) to reduce surface tension between two distinct fluid phases. However, implementation of simple surfactants has been hindered by the broad range of applications in water containing alkaline earth metals (i.e., hard water). This disrupts surfactant function and requires extensive use of undesirable and expensive chelating additives. We show that sugar-derived furans can be linked with triglyceride-derived fatty acid chains via Friedel–Crafts acylation within single layer (SPP) zeolite catalysts. Finally, these alkylfuran surfactants independently suppress the effects of hard water whilemore » simultaneously permitting broad tunability of size, structure, and function, which can be optimized for superior capability for forming micelles and solubilizing in water.« less

Tunable Oleo-Furan Surfactants by Acylation of Renewable Furans

DOE Office of Scientific and Technical Information (OSTI.GOV)

Park, Dae Sung; Joseph, Kristeen E.; Koehle, Maura

2016-11-23

An important advance in fluid surface control was the amphiphilic surfactant comprised of coupled molecular structures (i.e. hydrophilic and hydrophobic) to reduce surface tension between two distinct fluid phases. However, implementation of simple surfactants has been hindered by the broad range of applications in water containing alkaline earth metals (i.e. hard water), which disrupt surfactant function and require extensive use of undesirable and expensive chelating additives. Here we show that sugar-derived furans can be linked with triglyceride-derived fatty acid chains via Friedel-Crafts acylation within single layer (SPP) zeolite catalysts. These alkylfuran surfactants independently suppress the effects of hard water whilemore » simultaneously permitting broad tunability of size, structure, and function, which can be optimized for superior capability for forming micelles and solubilizing in water.« less

Indole synthesis by palladium-catalyzed tandem allylic isomerization - furan Diels-Alder reaction.

PubMed

Xu, Jie; Wipf, Peter

2017-08-30

A Pd(0)-catalyzed elimination of an allylic acetate generates a π-allyl complex that is postulated to initiate a novel intramolecular Diels-Alder cycloaddition to a tethered furan (IMDAF). Under the reaction conditions, this convergent, microwave-accelerated cascade process provides substituted indoles in moderate to good yields after Pd-hydride elimination, aromatization by dehydration, and in situ N-Boc cleavage.

Sustainable pathway to furanics from biomass via ...

EPA Pesticide Factsheets

An organic sulfonated graphitic carbon nitride is synthesized and its application has been demonstrated inthe conversion of carbohydrates into furanics and related value-added products. The most importantfeature of the material is the stability and acidity, which could be utilized at elevated temperatures forcleaving carbohydrates and converting them into biologically important scaffolds and platform chemicals. Prepared for submission to the Royal Society of Chemistry (RSC) Journal, Green Chemistry.

Reaction Paths and Chemical Activation Reactions of 2-Methyl-5-Furanyl Radical with 3O2.

PubMed

Hudzik, Jason M; Bozzelli, Joseph W

2017-10-05

Interest in high-energy substituted furans has been increasing due to their occurrence in biofuel production and their versatility in conversion to other useful products. Methylfurans are the simplest substituted furans and understanding their reaction pathways, thermochemical properties, including intermediate species stability, and chemical kinetics would aid in the study of larger furans. Furan ring C-H bonds have been shown to be extremely strong, approximately 120 kcal mol -1 , due in part to the placement of the oxygen atom and aromatic-like resonance, both within the ring. The thermochemistry and kinetics of the oxidation of 2-methyfuran radical at position 5 of the furan ring, 2-methyl-5-furanyl radical (2MF5j), is analyzed. The resulting chemically activated species, 2MF5OOj radical, has a well depth of 51 kcal mol -1 below the 2MF5j + O 2 reactants; this is 4-5 kcal mol -1 deeper than that of phenyl and vinyl radical plus O 2 , with both of these reactions known to undergo chain branching. Important, low-energy reaction pathways include chain branching dissociations, intramolecular abstractions, group transfers, and radical oxygen additions. Enthalpies of formation, entropies, and heat capacities for the stable molecules, radicals, and transition-state species are analyzed using computational methods. Calculated ΔH ° f 298 values were determined using an isodesmic work reaction from the CBS-QB3 composite method. Elementary rate parameters are from saddle point transition-state structures and compared to variational transition-state analysis for the barrierless reactions. Temperature- and pressure-dependent rate constants which are calculated using QRRK and master equation analysis is used for falloff and stabilization.

Potential State-selective Hydrogen Bond Formation Can Modulate Activation and Desensitization of the α7 Nicotinic Acetylcholine Receptor*

PubMed Central

Wang, Jingyi; Papke, Roger L.; Stokes, Clare; Horenstein, Nicole A.

2012-01-01

A series of arylidene anabaseines were synthesized to probe the functional impact of hydrogen bonding on human α7 nicotinic acetylcholine receptor (nAChR) activation and desensitization. The aryl groups were either hydrogen bond acceptors (furans), donors (pyrroles), or neither (thiophenes). These compounds were tested against a series of point mutants of the ligand-binding domain residue Gln-57, a residue hypothesized to be proximate to the aryl group of the bound agonist and a putative hydrogen bonding partner. Q57K, Q57D, Q57E, and Q57L were chosen to remove the dual hydrogen bonding donor/acceptor ability of Gln-57 and replace it with hydrogen bond donating, hydrogen bond accepting, or nonhydrogen bonding ability. Activation of the receptor was compromised with hydrogen bonding mismatches, for example, pairing a pyrrole with Q57K or Q57L, or a furan anabaseine with Q57D or Q57E. Ligand co-applications with the positive allosteric modulator PNU-120596 produced significantly enhanced currents whose degree of enhancement was greater for 2-furans or -pyrroles than for their 3-substituted isomers, whereas the nonhydrogen bonding thiophenes failed to show this correlation. Interestingly, the PNU-120596 agonist co-application data revealed that for wild-type α7 nAChR, the 3-furan desensitized state was relatively stabilized compared with that of 2-furan, a reversal of the relationship observed with respect to the barrier for entry into the desensitized state. These data highlight the importance of hydrogen bonding on the receptor-ligand state, and suggest that it may be possible to fine-tune features of agonists that mediate state selection in the nAChR. PMID:22556416

Synthesis of fused tricyclic systems by thermal Cope rearrangement of furan-substituted vinyl cyclopropanes.

PubMed

Klaus, Verena; Wittmann, Stéphane; Senn, Hans M; Clark, J Stephen

2018-05-15

A novel method for the stereoselective construction of hexahydroazuleno[4,5-b]furans from simple precursors has been developed. The route involves the use of our recently developed Brønsted acid catalysed cyclisation reaction of acyclic ynenones to prepare fused 1-furanyl-2-alkenylcyclopropanes that undergo highly stereoselective thermal Cope rearrangement to produce fused tricyclic products. Substrates possessing an E-alkene undergo smooth Cope rearrangement at 40 °C, whereas the corresponding Z-isomers do not react at this temperature. Computational studies have been performed to explain the difference in behaviour of the E- and Z-isomers in the Cope rearrangement reaction. The hexahydroazuleno[4,5-b]furans produced by Cope rearrangement have potential as advanced intermediates for the synthesis of members of the guaianolide family of natural products.

Divergent Total Syntheses of Rhodomyrtosones A and B

PubMed Central

Gervais, Anais; Lazarski, Kiel E.; Porco, John A.

2015-01-01

Herein, we report total syntheses of the tetramethyldihydroxanthene natural product rhodomyrtosone B and the related bis-furan β-triketone natural product rhodomyrtosone A. Nickel-(II)-catalyzed 1,4-conjugate addition of an α-alkylidene-β-dicarbonyl substrate was developed to access the congener rhodomyrtosone B, and oxygenation of the same monoalkylidene derivative followed by cyclization was employed to obtain the bis-furan natural product rhodomyrtosone A. PMID:26351970

Synthesis of the Insecticide Prothrin and Its Analogues from Biomass-Derived 5-(Cloromethyl)furfural

DTIC Science & Technology

2013-12-19

the same synthetic approach. Preliminary testing of these furan-based pyrethroids against the yellow fever mosquito Aedes aegypti indicates promising...approach. Preliminary testing of these furan-based pyrethroids against the yellow fever mosquito Aedes aegypti indicates promising insecticidal... Aedes aegypti (established 1952) was reared in the insectary of the Mosquito and Fly Research Unit at the Center for Medical, Agricultural, and Veterinary

Development of a Passive Multisampling Method to Measure Dioxins/Furans and Other Contaminant Bioavailability in Aquatic Sediments

DTIC Science & Technology

2016-11-01

A.; Weinstein, M. P.; Lohmann, R. Trophodynamic behavior of hydrophobic organic contaminants in the aquatic food web of a tidal river. Environ. Sci...FINAL REPORT Development of a Passive Multisampling Method to Measure Dioxins/Furans and Other Contaminant Bioavailability in Aquatic...trade name, trademark, manufacturer , or otherwise, does not necessarily constitute or imply its endorsement, recommendation, or favoring by the

Qualitative and quantitative analysis of Dibenzofuran, Alkyldibenzofurans, and Benzo[b]naphthofurans in crude oils and source rock extracts

USGS Publications Warehouse

Meijun Li,; Ellis, Geoffrey S.

2015-01-01

Dibenzofuran (DBF), its alkylated homologues, and benzo[b]naphthofurans (BNFs) are common oxygen-heterocyclic aromatic compounds in crude oils and source rock extracts. A series of positional isomers of alkyldibenzofuran and benzo[b]naphthofuran were identified in mass chromatograms by comparison with internal standards and standard retention indices. The response factors of dibenzofuran in relation to internal standards were obtained by gas chromatography-mass spectrometry analyses of a set of mixed solutions with different concentration ratios. Perdeuterated dibenzofuran and dibenzothiophene are optimal internal standards for quantitative analyses of furan compounds in crude oils and source rock extracts. The average concentration of the total DBFs in oils derived from siliciclastic lacustrine rock extracts from the Beibuwan Basin, South China Sea, was 518 μg/g, which is about 5 times that observed in the oils from carbonate source rocks in the Tarim Basin, Northwest China. The BNFs occur ubiquitously in source rock extracts and related oils of various origins. The results of this work suggest that the relative abundance of benzo[b]naphthofuran isomers, that is, the benzo[b]naphtho[2,1-d]furan/{benzo[b]naphtho[2,1-d]furan + benzo[b]naphtho[1,2-d]furan} ratio, may be a potential molecular geochemical parameter to indicate oil migration pathways and distances.

Exposure and effects of chemical contaminants on tree swallows nesting along the Housatonic River, Berkshire County, Massachusetts, USA, 1998-2000

USGS Publications Warehouse

Custer, Christine M.; Custer, T.W.; Dummer, P.M.; Munney, K.L.

2003-01-01

Hatching success of tree swallows (Tachycineta bicolor) was assessed for three years in relation to chemical contamination along the Housatonic River, Berkshire County (MA, USA), in 1998, 1999, and 2000. Nest boxes were erected at five sites along the Housatonic River and its tributaries and at one reference location. Concentrations of total polychlorinated biphenyls (PCBs) were some of the highest ever reported in bird eggs. Mean concentrations at sites along the Housatonic River ranged between 32 and 101 I?g/g wet weight. A significant negative relationship was observed between concentrations of total PCBs in clutches and hatching success. A significant negative relationship was also observed between hatching success and the sum of the total dioxins and furans and the associated toxic equivalents (TEQs) for dioxins and furans. In a combined model with PCB TEQs and dioxin/furan TEQs, PCB TEQs were not significantly correlated to hatching success, whereas dioxin/furan TEQs were. Contamination of tree swallows was from local food sources. Accumulation rates of total PCBs in 12-d-old nestlings averaged between 34 and 76 I?g/d at the sites along the main stem of the Housatonic River compared to <1 I?g/d at the reference location.

An Asymmetric Furan/Thieno[3,2-b]Thiophene Diketopyrrolopyrrole Building Block for Annealing-Free Green-Solvent Processable Organic Thin-Film Transistors.

PubMed

Ding, Shang; Ni, Zhenjie; Hu, Mengxiao; Qiu, Gege; Li, Jie; Ye, Jun; Zhang, Xiaotao; Liu, Feng; Dong, Huanli; Hu, Wenping

2018-06-21

A new asymmetric furan and thieno[3,2-b]thiophene flanked diketopyrrolopyrrole (TTFDPP) building block for conjugated polymers is designed and used to generate a donor-acceptor semiconducting polymer, poly[3-(furan-2-yl)-2,5-bis(2-octyldodecyl)-6-(thieno[3,2-b]thiophen-2-yl)pyrrolo[3,4-c]pyrrole-1,4(2H,5H)-dione-alt-thieno[3,2-b]thiophene] (abbreviated to PTTFDPP-TT), consisting of TTFDPP unit copolymerized with thieno[3,2-b]thiophene comonomer (TT), which is further synthesized. Results demonstrate that PTTFDPP-TT-based thin-film transistors in a bottom-gate bottom-contact device configuration exhibit typical hole-transporting property, with weak temperature dependence for charge carrier mobility from room temperature to 200 °C. In addition, the good solubility of PTTFDPP-TT due to the incorporation of a polar furan unit and an asymmetric conjugated structure makes it able to be solution processed with a less toxic nonchlorinated solvent such as toluene, demonstrating comparable performance with that prepared from chlorinated solution. These results suggest PTTFDPP-TT as a promising organic semiconductor candidate for annealing-free, environmentally benign, and less energy-consuming applications in large-area flexible organic electronic devices. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Palladium-Catalyzed Indole, Pyrrole, and Furan Arylation by Aryl Chlorides

PubMed Central

Nadres, Enrico T.; Lazareva, Anna; Daugulis, Olafs

2011-01-01

The palladium-catalyzed direct arylation of indoles, pyrroles, and furans by aryl chlorides has been demonstrated. The method employs a palladium acetate catalyst, 2-(dicyclohexylphosphino)-biphenyl ligand, and an inorganic base. Electron-rich and electron-poor aryl chlorides as well as chloropyridine coupling partners can be used and arylated heterocycles are obtained in moderate to good yields. Optimization of base, ligand, and solvent is required for achieving best results. PMID:21192652

DETERMINATION OF 2,3,7,8 CHLORINE-SUBSTITUTED DIBENZO-P-DIOXINS AND FURANS AT THE PART PER TRILLION LEVEL IN UNITED STATES BEEF FAT USING HIGH-RESOLUTION GAS CHROMATOGRAPHY/HIGH-RESOLUTION MASS SPECTROMETRY

EPA Science Inventory

As part of the U.S. EPA Dioxin Reassessment Program, the 2,3,7,8-chlorine-substituted dibenzo-p-dioxins and furans were measured at part per trillion (ppt) levels in beef fat collected from slaughter facilities in the United States. This is the first statistically designed natio...

Method of making a composite refractory material

DOEpatents

Morrow, Marvin S.; Holcombe, Cressie E.

1995-01-01

A composite refractory material is prepared by combining boron carbide with furan resin to form a mixture containing about 8 wt. % furan resin. The mixture is formed into a pellet which is placed into a grit pack comprising an oxide of an element such as yttrium to form a sinterable body. The sinterable body is sintered under vacuum with microwave energy at a temperature no greater than 2000.degree. C. to form a composite refractory material.

Method of making a composite refractory material

DOEpatents

Morrow, M.S.; Holcombe, C.E.

1995-09-26

A composite refractory material is prepared by combining boron carbide with furan resin to form a mixture containing about 8 wt. % furan resin. The mixture is formed into a pellet which is placed into a grit pack comprising an oxide of an element such as yttrium to form a sinterable body. The sinterable body is sintered under vacuum with microwave energy at a temperature no greater than 2000 C to form a composite refractory material.

From Biomass-Derived Furans to Aromatics with Ethanol over Zeolite.

PubMed

Teixeira, Ivo F; Lo, Benedict T W; Kostetskyy, Pavlo; Stamatakis, Michail; Ye, Lin; Tang, Chiu C; Mpourmpakis, Giannis; Tsang, Shik Chi Edman

2016-10-10

We report a novel catalytic conversion of biomass-derived furans and alcohols to aromatics over zeolite catalysts. Aromatics are formed via Diels-Alder cycloaddition with ethylene, which is produced in situ from ethanol dehydration. The use of liquid ethanol instead of gaseous ethylene, as the source of dienophile in this one-pot synthesis, makes the aromatics production much simpler and renewable, circumventing the use of ethylene at high pressure. More importantly, both our experiments and theoretical studies demonstrate that the use of ethanol instead of ethylene, results in significantly higher rates and higher selectivity to aromatics, due to lower activation barriers over the solid acid sites. Synchrotron-diffraction experiments and proton-affinity calculations clearly suggest that a preferred protonation of ethanol over the furan is a key step facilitating the Diels-Alder and dehydration reactions in the acid sites of the zeolite. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Synthesis of furan-3-carboxylic and 4-methylene-4,5-dihydrofuran-3-carboxylic esters by direct palladium iodide catalyzed oxidative carbonylation of 3-yne-1,2-diol derivatives.

PubMed

Gabriele, Bartolo; Mancuso, Raffaella; Maltese, Vito; Veltri, Lucia; Salerno, Giuseppe

2012-10-05

A variety of 3-yne-1,2-diol derivatives 1, bearing a primary or secondary alcoholic group at C-1, have been efficiently converted into high value added furan-3-carboxylic esters 2 in one step by PdI(2)/KI-catalyzed direct oxidative carbonylation, carried out in alcoholic media under relatively mild conditions (100 °C under 40 atm of a 4/1 mixture of CO and air). Carbonylated furans 2 were obtained in fair to excellent isolated yields (56-93%) through a sequential 5-endo-dig heterocyclization-alkoxycarbonylation-dehydration process, using only oxygen as the external oxidant. Under similar conditions, 2-methyl-3-yne-1,2-diols 3, bearing a tertiary alcoholic group, afforded 4-methylene-4,5-dihydrofuran-3-carboxylates 4 in satisfactory yields (58-70%).

Opening Furan for Tailoring Properties of Bio-based Poly(Furfuryl Alcohol) Thermoset.

PubMed

Falco, Guillaume; Guigo, Nathanael; Vincent, Luc; Sbirrazzuoli, Nicolas

2018-06-11

This work shows how furan ring-opening reactions were controlled by polymerization conditions to tune the cross-link density in bio-based poly(furfuryl alcohol) (PFA). The influence of water and isopropyl alcohol (IPA) on the polymerization of furfuryl alcohol, and particularly on furan ring-opening, was investigated by means of 13 C NMR and FT-IR spectroscopy. Results indicated that formation of open structures were favored in the presence of solvents, thus leading to modification of the thermo-mechanical properties compared to PFA cross-linked without solvent. Dynamic mechanical analyses showed that when slightly more open structures were present in PFA it resulted in an important decrease of the cross-link density. Despite lower glass-transition temperature and lower elastic modulus for PFA polymerized with solvent, the thermal stability remains very high (>350 °C) even with more open structures in PFA. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Synthesis, anticancer activity, and iron affinity of the Actinoplanes metabolite 7,8-dihydroxy-1-methylnaphtho[2,3-c]furan-4,9-dione.

PubMed

Breyer, Sandra; Effenberger-Neidnicht, Katharina; Knauer, Sebastian; Schobert, Rainer

2011-02-01

The first synthesis of 7,8-dihydroxy-1-methylnaphtho[2,3-c]furan-4,9-dione (1), an isofuranonaphthoquinone produced by an Actinoplanes strain is described. Lactone ring opening of 6-methylfuro[3,4-c]furan-1(3H)-one (4) with ortho-lithiated veratrole (3), oxidation of product alcohol 5, and Friedel-Crafts acylation of the resulting aroylcarboxylic acid 7 afforded the mono methyl ether 2 of the target compound. The latter was obtained by demethylation of 2 with BBr(3) in 14% overall yield. While mono ether 2 was distinctly more cytotoxic than catechol 1 against a panel of five cancer cell lines, only the latter showed a siderophore-like binding affinity for Fe(III) with a complex dissociation constant K(D) of approximately 10(-29) M(3) (pM = 25.9). Copyright © 2010 Elsevier Ltd. All rights reserved.

Exploring green catalysts for production of biofuels and value added chemicals for renewable and sustainable energy future

NASA Astrophysics Data System (ADS)

Budhi, Sridhar

Porous silica have attracted significant attention in the past few decades due to their unique textural properties. They were extensively investigated for applications in catalysis, separation, environmental remediation and drug delivery. We have investigated the porous metal incorporated silica in the synthetic as well as catalytic perspectives. The synthesis of metal incorporated mesoporous silica via co-condensation such as SBA-15, KIT-5 are still challenging as it involves acidic synthetic route. Synthesis in high acidity conditions affects the incorporation of metal in silica due to high dissolution of metal precursors and breaking of metal oxygen and silica bond. The research presented here demonstrates an efficient way to incorporate metals by addition of diammonium hydrogen phosphate along with metal precursor during the synthesis. The incorporation efficiency has increased 2-3 times with this approach. Catalytic studies were performed to support our hypothesis. Such synthesized molybdenum incorporated mesoporous silica were investigated as catalyst for fast pyrolysis. When molydenum incorporated in silica was used as catalyst for fast pyrolysis of pine, it selectively produced furans (furan, methylfuran and dimethylfuran). Furans are considered value-added chemicals and can be used as a blendstock for diesel/jet grade fuel. The catalyst was very stable to harsh pyrolysis conditions and had a longer life before deactivation when compared with traditional zeolites. Further, this catalyst did not produce aromatic hydrocarbons in significant yields unlike zeolites. The origin of the furans was determined to be biopolymer cellulose and the selectivity for furans are attributed to low catalyst acidity. The effect of silica to alumina ratio (SAR) of beta-zeolite was investigated ranging to elucidate the relationship between the of number of acid sites on product speciation and catalyst deactivation on catalysts supplied by Johnson Matthey. The catalyst with low SAR (more acid sites) produced predominantly aromatic hydrocarbons and olefins with no detectable oxygen containing species. In contrary, the catalyst with high SAR (fewer acid sites) produced a suite of oxygenated products such as furans, phenols and cresols. The coke deposited on each catalyst and the yield of aromatic hydrocarbons were in direct proportion to the number of acid sites. When catalysts were active, the biomass selectivity towards hydrocarbons and amount of coke were constant regardless of SAR.

Tests for genotoxicity and mutagenicity of furan and its metabolite cis-2-butene-1,4-dial in L5178Y tk+/- mouse lymphoma cells.

PubMed

Kellert, Marco; Brink, Andreas; Richter, Ingrid; Schlatter, Josef; Lutz, Werner K

2008-12-08

Furan is found in various food items and is cytotoxic and carcinogenic in the liver of rats and mice. Metabolism of furan includes the formation of an unsaturated dialdehyde, cis-2-butene-1,4-dial (BDA). In view of the multifunctional electrophilic reactivity of BDA, adduct formation with protein and DNA may explain some of the toxic effects. Short-term tests for genotoxicity of furan in mammalian cells are inconclusive, little is known for BDA. We investigated BDA generated by hydrolysis of 2,5-diacetoxy-2,5-dihydrofuran for genotoxicity in L5178Y tk+/- mouse lymphoma cells using standard procedures for the comet assay, the micronucleus test, and the mouse lymphoma thymidine kinase gene mutation assay, using 4-h incubation periods. Cytotoxicity was remarkable: cell viability at concentrations>or=50 microM was reduced to <50%. In the dose range up to 25 microM, viability was >90%. Measures of comet-tail length and thymidine-kinase mutant frequency were increased 1.6- and 2.4-fold above control, respectively. Analysis of three fully independent replicates with a linear mixed-effects model showed a highly significant increase with concentration for both endpoints. Compared to methyl methanesulfonate used as a positive control, BDA was of similar potency with respect to genotoxicity, but it was much more cytotoxic. Furan added to cell cultures at doses that resulted in time-averaged effective concentrations of up to 3100 microM was neither cytotoxic nor genotoxic. A potential cross-linking activity of BDA was investigated by checking whether gamma radiation-induced DNA migration in the comet assay could be reduced by pre-treatment with BDA. In contrast to the effect of the positive control glutaraldehyde, BDA treatment did not reduce the comet tail length. On the contrary, an increase was observed at >or=100 microM BDA, which was attributable to early apoptotic cells. Although BDA was found to be a relatively potent genotoxic agent in terms of the concentration necessary to double the background measures, cytotoxicity strongly limited the concentration range that produced interpretable results. This may explain some of the inconclusive results and indicates that non-genotoxic effects must be taken into account in the discussion of the modes of toxic and carcinogenic action of furan.

Technical Requirements for On-Site Thermal Desorption of Solid Media Contaminated with Hazardous Chlorinated Organics

DTIC Science & Technology

1997-09-18

scrubbers , detectable dioxin/furans may occur, since dioxin/furans are much more soluble in organics than in water. Carbon adsorption is frequently...air pollution control device is required. Acid gases may be controlled by using a wet or dry scrubber or by using a coated baghouse. Operating...unit: 1. exit treated waste temperature; 2. baghouse pressure drop, venturi pressure drop, or drop in liquid/gas ratio; 3. waste feed rate; 4

Environmental Compliance Assessment System (USA ECAS)

DTIC Science & Technology

1991-09-01

Fuberidazole 100/10,000 3878-19-1 Fulminic acid , mercu- 10 P065 628-86-4 ry(I1) salt Fumaric acid 5000 110-17-8 Furan, tetrahydro- 1000 LT213 109-99-9 Furan...etc.)? S. Does the installation have any bulk acid storage? 6. Does the installation store batteries and/or have a battery reclamation point? I...gas turbines (greater than 1 MBtuhr) - bulk gasoline terminals - municipal waste combustors - sulfuric and nitric acid plants - rotogravure printers

5-Hydroxyindoles by intramolecular alkynol-furan diels-alder cycloaddition.

PubMed

LaPorte, Matthew; Hong, Ki Bum; Xu, Jie; Wipf, Peter

2013-01-04

A convergent approach provides a convenient access to synthetically and biologically useful 3,4-disubstituted 5-hydroxyindoles. The one-pot procedure uses microwave heating to initiate an intramolecular [4 + 2]-cycloaddition of an alkynol segment onto a furan followed by a fragmentation, aromatization, and N-Boc deprotection cascade. Yields range from 15 to 74%, with aromatic substituents providing better conversions. 4-Trimethylsilylated analogues undergo a 1,3-silatropic rearrangement to give the O-TMS ethers.

Catalytic conversion of cellulose to fuels and chemicals using boronic acids

DOEpatents

Raines, Ronald; Caes, Benjamin; Palte, Michael

2015-10-20

Methods and catalyst compositions for formation of furans from carbohydrates. A carbohydrate substrate is heating in the presence of a 2-substituted phenylboronic acid (or salt or hydrate thereof) and optionally a magnesium or calcium halide salt. The reaction is carried out in a polar aprotic solvent other than an ionic liquid, an ionic liquid or a mixture thereof. Additional of a selected amount of water to the reaction can enhance the yield of furans.

Separation of chemical groups from bio-oil aqueous phase via sequential organic solvent extraction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ren, Shoujie; Ye, Philip; Borole, Abhijeet P

Bio-oil aqueous phase contains a considerable amount of furans, alcohols, ketones, aldehydes and phenolics besides the major components of organic acids and anhydrosugars. The complexity of bio-oil aqueous phase limits its efficient utilization. To improve the efficiency of bio-oil biorefinery, this study focused on the separation of chemical groups from bio-oil aqueous phase via sequential organic solvent extractions. Due to their high recoverability and low solubility in water, four solvents (hexane, petroleum ether, chloroform, and ethyl acetate) with different polarities were evaluated, and the optimum process conditions for chemical extraction were determined. Chloroform had high extraction efficiency for furans, phenolics,more » and ketones. In addition to these chemical groups, ethyl acetate had high extraction efficiency for organic acids. The sequential extraction by using chloroform followed by ethyl acetate rendered that 62.2 wt.% of original furans, ketones, alcohols, and phenolics were extracted to chloroform, over 62 wt.% acetic acid was extracted to ethyl acetate, resulting in a high concentration of levoglucosan (~53.0 wt.%) in the final aqueous phase. Chemicals separated via the sequential extraction could be used as feedstocks in biorefinery using processes such as catalytic upgrading of furans and phenolics to hydrocarbons, fermentation of levoglucosan to produce alcohols and diols, and hydrogen production from organic acids via microbial electrolysis.« less

Separation of chemical groups from bio-oil aqueous phase via sequential organic solvent extraction

DOE PAGES

Ren, Shoujie; Ye, Philip; Borole, Abhijeet P

2017-01-05

Bio-oil aqueous phase contains a considerable amount of furans, alcohols, ketones, aldehydes and phenolics besides the major components of organic acids and anhydrosugars. The complexity of bio-oil aqueous phase limits its efficient utilization. To improve the efficiency of bio-oil biorefinery, this study focused on the separation of chemical groups from bio-oil aqueous phase via sequential organic solvent extractions. Due to their high recoverability and low solubility in water, four solvents (hexane, petroleum ether, chloroform, and ethyl acetate) with different polarities were evaluated, and the optimum process conditions for chemical extraction were determined. Chloroform had high extraction efficiency for furans, phenolics,more » and ketones. In addition to these chemical groups, ethyl acetate had high extraction efficiency for organic acids. The sequential extraction by using chloroform followed by ethyl acetate rendered that 62.2 wt.% of original furans, ketones, alcohols, and phenolics were extracted to chloroform, over 62 wt.% acetic acid was extracted to ethyl acetate, resulting in a high concentration of levoglucosan (~53.0 wt.%) in the final aqueous phase. Chemicals separated via the sequential extraction could be used as feedstocks in biorefinery using processes such as catalytic upgrading of furans and phenolics to hydrocarbons, fermentation of levoglucosan to produce alcohols and diols, and hydrogen production from organic acids via microbial electrolysis.« less

Biomarkers of furan exposure by metabolic profiling of rat urine with liquid chromatography-tandem mass spectrometry and principal component analysis.

PubMed

Kellert, Marco; Wagner, Silvia; Lutz, Ursula; Lutz, Werner K

2008-03-01

Furan has been found in a number of heated food items and is carcinogenic in the liver of rats and mice. Estimates of human exposure on the basis of concentrations measured in food are not reliable because of the volatility of furan. A biomarker approach is therefore indicated. We searched for metabolites excreted in the urine of male Fischer 344 rats treated by oral gavage with 40 mg of furan per kg of body weight. A control group received the vehicle oil only. Urine collected over two 24-h periods both before and after treatment was analyzed by a column-switching LC-MS/MS method. Data were acquired by a full scan survey scan in combination with information dependent acquisition of fragmentation spectra by the use of a linear ion trap. Areas of 449 peaks were extracted from the chromatograms and used for principal component analysis (PCA). The first principal component fully separated the samples of treated rats from the controls in the first post-treatment sampling period. Thirteen potential biomarkers selected from the corresponding loadings plot were reanalyzed using specific transitions in the MRM mode. Seven peaks that increased significantly upon treatment were further investigated as biomarkers of exposure. MS/MS information indicated conjugation with glutathione on the basis of the characteristic neutral loss of 129 for mercapturates. Adducts with the side chain amino group of lysine were characterized by a neutral loss of 171 for N-acetyl- l-lysine. Analysis of products of in vitro incubations of the reactive furan metabolite cis-2-butene-1,4-dial with the respective amino acid derivatives supported five structures, including a new 3-methylthio-pyrrole metabolite probably formed by beta-lyase reaction on a glutathione conjugate, followed by methylation of the thiol group. Our results demonstrate the potential of comprehensive mass spectrometric analysis of urine combined with multivariate analyses for metabolic profiling in search of biomarkers of exposure.

Thermochemistry of Hydroxyl and Hydroperoxide Substituted Furan, Methylfuran, and Methoxyfuran.

PubMed

Hudzik, Jason M; Bozzelli, Joseph W

2017-06-15

Reaction pathways are influenced by thermochemical properties, species stability, and chemical kinetics. Understanding these factors allows for an understanding of the reaction paths and formation of intermediate species. Enthalpies of formation (ΔH f,298 ° ), entropies (S 298 ° ), heat capacities (C p (T)), oxygen-hydrogen (O-H), oxygen-oxygen (O-O), and (R-O) bond dissociation energies (BDEs) are reported for hydroxyl and hydroperoxide substituted furan, methylfuran, and methoxyfuran species. Standard enthalpies of formation for parent and radical species have been determined using density functional theory B3LYP/6-31G(d,p), B3LYP/6-311G(2d,2p), and M06-2X/6-31G(d,p) along with higher-level CBS-QB3 and CBS-APNO composite methods. Isodesmic work reactions were employed to improve accuracy by canceling error and show consistency between the levels of theory. Corresponding O-H and O-O BDEs are determined and compared to other similar structures. The stability of the furan moiety coupled with the double-bond-forming capability of the oxygen moiety results in a number of bond energies significantly lower than one might have expected. Substituted hydroperoxides are calculated to have ROO-H BDEs between 86.9 and 94.2 kcal mol -1 , and their RO-OH BDEs show a large 49 kcal mol -1 range of -2.3-46.8 kcal mol -1 . Substituted alcohols also show a wide 48 kcal mol -1 range with RO-H BDEs, ranging from 59.3 to 106.9 kcal mol -1 . Bond lengths of parent and radical species are presented to highlight potential bonds of interest leading to furan ring opening. Group additivity is discussed, and groups for substituted furan, methylfuran, and methoxyfuran species are derived. Structures, moments of inertia, vibrational frequencies, and internal rotor potentials are calculated at the B3LYP/6-31G(d,p) density functional level and are used to determine the S 298 ° and C p (T) values.

Furan Fragmentation in the Gas Phase: New Insights from Statistical and Molecular Dynamics Calculations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Erdmann, Ewa; Labuda, Marta; Aguirre, Nestor F.

We present a complete exploration of the different fragmentation mechanisms of furan (C 4H 4O) operating at low and high energies. Three different theoretical approaches are combined to determine the structure of all possible reaction intermediates, many of them not described in previous studies, and a large number of pathways involving three types of fundamental elementary mechanisms: isomerization, fragmentation, and H/H 2 loss processes (this last one was not yet explored). Our results are compared with the existing experimental and theoretical investigations for furan fragmentation. At low energies the first processes to appear are isomerization, which always implies the breakingmore » of one C–O bond and one or several hydrogen transfers; at intermediate energies the fragmentation of the molecular skeleton becomes the most relevant mechanism; and H/H 2 loss is the dominant processes at high energy. However, the three mechanisms are active in very wide energy ranges and, therefore, at most energies there is a competition among them.« less

Furan Fragmentation in the Gas Phase: New Insights from Statistical and Molecular Dynamics Calculations

DOE PAGES

Erdmann, Ewa; Labuda, Marta; Aguirre, Nestor F.; ...

2018-03-15

We present a complete exploration of the different fragmentation mechanisms of furan (C 4H 4O) operating at low and high energies. Three different theoretical approaches are combined to determine the structure of all possible reaction intermediates, many of them not described in previous studies, and a large number of pathways involving three types of fundamental elementary mechanisms: isomerization, fragmentation, and H/H 2 loss processes (this last one was not yet explored). Our results are compared with the existing experimental and theoretical investigations for furan fragmentation. At low energies the first processes to appear are isomerization, which always implies the breakingmore » of one C–O bond and one or several hydrogen transfers; at intermediate energies the fragmentation of the molecular skeleton becomes the most relevant mechanism; and H/H 2 loss is the dominant processes at high energy. However, the three mechanisms are active in very wide energy ranges and, therefore, at most energies there is a competition among them.« less

High-level ab initio enthalpies of formation of 2,5-dimethylfuran, 2-methylfuran, and furan.

PubMed

Feller, David; Simmie, John M

2012-11-29

A high-level ab initio thermochemical technique, known as the Feller-Petersen-Dixon method, is used to calculate the total atomization energies and hence the enthalpies of formation of 2,5-dimethylfuran, 2-methylfuran, and furan itself as a means of rationalizing significant discrepancies in the literature. In order to avoid extremely large standard coupled cluster theory calculations, the explicitly correlated CCSD(T)-F12b variation was used with basis sets up to cc-pVQZ-F12. After extrapolating to the complete basis set limit and applying corrections for core/valence, scalar relativistic, and higher order effects, the final Δ(f)H° (298.15 K) values, with the available experimental values in parentheses are furan -34.8 ± 3 (-34.7 ± 0.8), 2-methylfuran -80.3 ± 5 (-76.4 ± 1.2), and 2,5-dimethylfuran -124.6 ± 6 (-128.1 ± 1.1) kJ mol(-1). The theoretical results exhibit a compelling internal consistency.

Pd/NbOPO₄ multifunctional catalyst for the direct production of liquid alkanes from aldol adducts of furans.

PubMed

Xia, Qi-Neng; Cuan, Qian; Liu, Xiao-Hui; Gong, Xue-Qing; Lu, Guan-Zhong; Wang, Yan-Qin

2014-09-08

Great efforts have been made to convert renewable biomass into transportation fuels. Herein, we report the novel properties of NbO(x)-based catalysts in the hydrodeoxygenation of furan-derived adducts to liquid alkanes. Excellent activity and stability were observed with almost no decrease in octane yield (>90% throughout) in a 256 h time-on-stream test. Experimental and theoretical studies showed that NbO(x) species play the key role in C-O bond cleavage. As a multifunctional catalyst, Pd/NbOPO4 plays three roles in the conversion of aldol adducts into alkanes: 1) The noble metal (in this case Pd) is the active center for hydrogenation; 2) NbO(x) species help to cleave the C-O bond, especially of the tetrahydrofuran ring; and 3) a niobium-based solid acid catalyzes the dehydration, thus enabling the quantitative conversion of furan-derived adducts into alkanes under mild conditions. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Butanol production from lignocellulose by simultaneous fermentation, saccharification, and pervaporation or vacuum evaporation.

PubMed

Díaz, Víctor Hugo Grisales; Tost, Gerard Olivar

2016-10-01

Techno-economic study of acetone, butanol and ethanol (ABE) fermentation from lignocellulose was performed. Simultaneous saccharification, fermentation and vacuum evaporation (SFS-V) or pervaporation (SFS-P) were proposed. A kinetic model of metabolic pathways for ABE fermentation with the effect of phenolics and furans in the growth was proposed based on published laboratory results. The processes were optimized in Matlab®. The end ABE purification was carried out by heat-integrated distillation. The objective function of the minimization was the total annualized cost (TAC). Fuel consumption of SFS-P using poly[1-(trimethylsilyl)-1-propyne] membrane was between 13.8 and 19.6% lower than SFS-V. Recovery of furans and phenolics for the hybrid reactors was difficult for its high boiling point. TAC of SFS-P was increased 1.9 times with supplementation of phenolics and furans to 3g/l each one for its high toxicity. Therefore, an additional detoxification method or an efficient pretreatment process will be necessary. Copyright © 2016 Elsevier Ltd. All rights reserved.

High concentrations of furan fatty acids in organic butter samples from the German market.

PubMed

Wendlinger, Christine; Vetter, Walter

2014-08-27

Furan fatty acids (F-acids) are valuable antioxidants containing a furan moiety in the central part of the molecule. They occur in the lipids of different foodstuffs and plants, with grass being the main source for their presence in milk fat and butter. Because cows from organic farming receive higher portions of grass-based feed, it was tested whether organic butter samples (n = 26) contain more F-acids than conventional ones (n = 25) in Germany. For this purpose, samples were melted, and the lipid phase was separated and transesterified into methyl esters, which were enriched using silver ion chromatography and analyzed by GC-EI/MS in the selected ion monitoring (SIM) mode. Levels of F-acids in butter were higher in summer than in winter, and in both seasons, organic samples contained significantly higher levels of F-acids than conventional ones (one-way ANOVA: p < 0.001). Furthermore, the daily intake of F-acids via milk fat and other foodstuffs was calculated.

Effects of furan derivatives and phenolic compounds on electricity generation in microbial fuel cells

NASA Astrophysics Data System (ADS)

Catal, Tunc; Fan, Yanzhen; Li, Kaichang; Bermek, Hakan; Liu, Hong

Lignocellulosic biomass is an attractive fuel source for MFCs due to its renewable nature and ready availability. Furan derivatives and phenolic compounds could be potentially formed during the pre-treatment process of lignocellulosic biomass. In this study, voltage generation from these compounds and the effects of these compounds on voltage generation from glucose in air-cathode microbial fuel cells (MFCs) were examined. Except for 5-hydroxymethyl furfural (5-HMF), all the other compounds tested were unable to be utilized directly for electricity production in MFCs in the absence of other electron donors. One furan derivate, 5-HMF and two phenolic compounds, trans-cinnamic acid and 3,5-dimethoxy-4-hydroxy-cinnamic acid did not affect electricity generation from glucose at a concentration up to 10 mM. Four phenolic compounds, including syringaldeyhde, vanillin, trans-4-hydroxy-3-methoxy, and 4-hydroxy cinnamic acids inhibited electricity generation at concentrations above 5 mM. Other compounds, including 2-furaldehyde, benzyl alcohol and acetophenone, inhibited the electricity generation even at concentrations less than 0.2 mM. This study suggests that effective electricity generation from the hydrolysates of lignocellulosic biomass in MFCs may require the employment of the hydrolysis methods with low furan derivatives and phenolic compounds production, or the removal of some strong inhibitors prior to the MFC operation, or the improvement of bacterial tolerance against these compounds through the enrichment of new bacterial cultures or genetic modification of the bacterial strains.

Temperature and electrolyte optimization of the α-hemolysin latch sensing zone for detection of base modification in double-stranded DNA.

PubMed

Johnson, Robert P; Fleming, Aaron M; Jin, Qian; Burrows, Cynthia J; White, Henry S

2014-08-19

The latch region of the wild-type protein pore α-hemolysin (α-HL) constitutes a sensing zone for individual abasic sites (and furan analogs) in double-stranded DNA (dsDNA). The presence of an abasic site or furan within a DNA duplex, electrophoretically captured in the α-HL vestibule and positioned at the latch region, can be detected based on the current blockage prior to duplex unzipping. We investigated variations in blockage current as a function of temperature (12-35°C) and KCl concentration (0.15-1.0 M) to understand the origin of the current signature and to optimize conditions for identifying the base modification. In 1 M KCl solution, substitution of a furan for a cytosine base in the latch region results in an ∼ 8 kJ mol(-1) decrease in the activation energy for ion transport through the protein pore. This corresponds to a readily measured ∼ 2 pA increase in current at room temperature. Optimal resolution for detecting the presence of a furan in the latch region is achieved at lower KCl concentrations, where the noise in the measured blockage current is significantly lower. The noise associated with the blockage current also depends on the stability of the duplex (as measured from the melting temperature), where a greater noise in the measured blockage current is observed for less stable duplexes. Copyright © 2014 Biophysical Society. Published by Elsevier Inc. All rights reserved.

Contaminant trends in sport fish from Lake Roosevelt and the upper Columbia River, Washington, 1994-1998

USGS Publications Warehouse

Munn, Mark D.

2000-01-01

Fish from Lake Roosevelt were first reported to contain elevated concentrations of contaminants in the early 1980?s, with mercury, dioxins and furans, and polychlorinated biphenyls (PCBs) identified as being of most concern to human health. Over the following years there were a series of studies by United States and Canadian agencies addressing contaminants in fish from both a human and environmental perspective. In the early 1990?s, industrial discharges to the Columbia River above the international boundary decreased. The dominant changes in industrial practices included a reduction in slag and effluent discharges from a lead-zinc smelter, and a reduction in dioxins and furans due to processing changes at a Canadian pulp mill. It is believed that these two alterations in industrial practices may have greatly reduced the loading of selected contaminants to the Columbia River system. In response to these recent changes, the U.S. Geological Survey initiated this present study for the purpose of determining the present concentrations of mercury, dioxins and furans, and PCBs in fish, and, if possible, to determine if concentrations have changed since the 1994 studies. All contaminant analysis was done on fish fillets in order to address human health concerns. Our study concluded that the concentrations of contaminants in fish that were identified as a potential threat to human health have either not changed since the 1994 studies, or have decreased. PCBs, as determined by Aroclor 1254, do not appear to have changed between 1994 and 1998; sources of PCBs are presently unknown. In contrast, dioxins and furans, as indicated by 2,3,7,8-TCDF, did show a significant decrease in rainbow trout fillets from 1994 to 1998. However, there was no apparent change in the average 2,3,7,8-TCDF concentrations in mountain whitefish, with the reason uncertain at this time. Average concentrations of 2,3,7,8-TCDF were higher in mountain whitefish than in rainbow trout. Toxicity equivalence concentrations (TEC) are determined by summing the relative toxicity of individual congeners of dioxins, furans, and toxic ?dioxin-like? PCB congeners in individual fish. Rainbow trout from the upper reach have higher TECs than rainbow trout from the lower reach, with trout from the upper reach having a higher percentage of the toxicity from toxic ?dioxin-like? PCBs than dioxin and furan compounds. In relation to mercury, the concentrations of total mercury in walleye have significantly decreased by about 50 percent from 1994 to 1998.

Ethyl 4-(2-fur-yl)-2-oxochroman-3-carboxyl-ate.

PubMed

Prabhakar, Maddela; Reddy, J S N; Kumar, N Ravi; Ganesh, S Viswanadha; Solomon, K Anand

2010-05-12

The title compound, C(16)H(14)O(5), was prepared from the reaction of 3-carbethoxy-coumarin with furan in the presence of AlCl(3) as catalyst. In the crystal, inter-molecular C-H⋯O hydrogen-bonding inter-actions between four mol-ecules lead to a tetra-mer in the unit cell. The furan ring is anti-periplanar [C-C-C-O = 167.9 (13)°] and the ethoxy-carbonyl group is (-)anti-clinal [C-C-C-O = -128.6 (14)°] to the lactone ring.

Heteroaromatic-based electrolytes for lithium and lithium-ion batteries

DOEpatents

Cheng, Gang; Abraham, Daniel P.

2017-04-18

The present invention provides an electrolyte for lithium and/or lithium-ion batteries comprising a lithium salt in a liquid carrier comprising heteroaromatic compound including a five-membered or six-membered heteroaromatic ring moiety selected from the group consisting of a furan, a pyrazine, a triazine, a pyrrole, and a thiophene, the heteroaromatic ring moiety bearing least one carboxylic ester or carboxylic anhydride substituent bound to at least one carbon atom of the heteroaromatic ring. Preferred heteroaromatic ring moieties include pyridine compounds, pyrazine compounds, pyrrole compounds, furan compounds, and thiophene compounds.

Gold-catalyzed sequential annulations towards 3,4-fused bi/tri-cyclic furans involving a [3+2+2]-cycloaddition.

PubMed

Liu, Suna; Yang, Pu; Peng, Shiyong; Zhu, Chenghao; Cao, Shengyu; Li, Jian; Sun, Jiangtao

2017-01-17

A gold-catalyzed sequential annulation reaction to prepare 3,4-fused bicyclic furan compounds has been realized by employing 2-(1-alkynyl)-2-alken-1-ones and 1,3,5-triazines as the starting materials under mild reaction conditions. This protocol features multiple bond formation in a single operation with the incorporation of two nitrogen and two carbon atoms into the final products. A mechanistic investigation reveals that the sequential annulations involved an unprecedented stepwise [3+2+2]-cycloaddition.

An easily accessible sulfated saccharide mimetic inhibits in vitro human tumor cell adhesion and angiogenesis of vascular endothelial cells

PubMed Central

Marano, Grazia; Gronewold, Claas; Frank, Martin; Merling, Anette; Kliem, Christian; Sauer, Sandra; Wiessler, Manfred; Frei, Eva

2012-01-01

Summary Oligosaccharides aberrantly expressed on tumor cells influence processes such as cell adhesion and modulation of the cell’s microenvironment resulting in an increased malignancy. Schmidt’s imidate strategy offers an effective method to synthesize libraries of various oligosaccharide mimetics. With the aim to perturb interactions of tumor cells with extracellular matrix proteins and host cells, molecules with 3,4-bis(hydroxymethyl)furan as core structure were synthesized and screened in biological assays for their abilities to interfere in cell adhesion and other steps of the metastatic cascade, such as tumor-induced angiogenesis. The most active compound, (4-{[(β-D-galactopyranosyl)oxy]methyl}furan-3-yl)methyl hydrogen sulfate (GSF), inhibited the activation of matrix-metalloproteinase-2 (MMP-2) as well as migration of the human melanoma cells of the lines WM-115 and WM-266-4 in a two-dimensional migration assay. GSF inhibited completely the adhesion of WM-115 cells to the extracellular matrix (ECM) proteins, fibrinogen and fibronectin. In an in vitro angiogenesis assay with human endothelial cells, GSF very effectively inhibited endothelial tubule formation and sprouting of blood vessels, as well as the adhesion of endothelial cells to ECM proteins. GSF was not cytotoxic at biologically active concentrations; neither were 3,4-bis{[(β-D-galactopyranosyl)oxy]methyl}furan (BGF) nor methyl β-D-galactopyranoside nor 3,4-bis(hydroxymethyl)furan, which were used as controls, eliciting comparable biological activity. In silico modeling experiments, in which binding of GSF to the extracellular domain of the integrin αvβ3 was determined, revealed specific docking of GSF to the same binding site as the natural peptidic ligands of this integrin. The sulfate in the molecule coordinated with one manganese ion in the binding site. These studies show that this chemically easily accessible molecule GSF, synthesized in three steps from 3,4-bis(hydroxymethyl)furan and benzoylated galactose imidate, is nontoxic and antagonizes cell physiological processes in vitro that are important for the dissemination and growth of tumor cells in vivo. PMID:23015827

Direct carbon-carbon coupling of furanics with acetic acid over Brønsted zeolites

PubMed Central

Gumidyala, Abhishek; Wang, Bin; Crossley, Steven

2016-01-01

Effective carbon-carbon coupling of acetic acid to form larger products while minimizing CO2 emissions is critical to achieving a step change in efficiency for the production of transportation fuels from sustainable biomass. We report the direct acylation of methylfuran with acetic acid in the presence of water, all of which can be readily produced from biomass. This direct coupling limits unwanted polymerization of furanics while producing acetyl methylfuran. Reaction kinetics and density functional theory calculations illustrate that the calculated apparent barrier for the dehydration of the acid to form surface acyl species is similar to the experimentally measured barrier, implying that this step plays a significant role in determining the net reaction rate. Water inhibits the overall rate, but selectivity to acylated products is not affected. We show that furanic species effectively stabilize the charge of the transition state, therefore lowering the overall activation barrier. These results demonstrate a promising new route to C–C bond–forming reactions for the production of higher-value products from biomass. PMID:27652345

Peniciadametizine A, a Dithiodiketopiperazine with a Unique Spiro[furan-2,7'-pyrazino[1,2-b][1,2]oxazine] Skeleton, and a Related Analogue, Peniciadametizine B, from the Marine Sponge-Derived Fungus Penicillium adametzioides.

PubMed

Liu, Yang; Mándi, Attila; Li, Xiao-Ming; Meng, Ling-Hong; Kurtán, Tibor; Wang, Bin-Gui

2015-06-05

Peniciadametizine A (1); a new dithiodiketopiperazine derivative possessing a unique spiro[furan-2,7'-pyrazino[1,2-b][1,2]oxazine] skeleton, together with a highly oxygenated new analogue, peniciadametizine B (2); as well as two known compounds, brasiliamide A (3); and viridicatumtoxin (4), were isolated and identified from Penicillium adametzioides AS-53, a fungus obtained from an unidentified marine sponge. The unambiguous assignment of the relative and absolute configuration for the spiro center C-2 of compound 1 was solved by the combination of NMR and ECD measurements with Density-Functional Theory (DFT) conformational analysis and Time-Dependent Density-Functional Theory-Electronic Circular Dichroism (TDDFT-ECD) calculations. The spiro[furan-2,7'-pyrazino[1,2-b][1,2]oxazine] skeleton of 1 has not been reported yet among natural products and the biosynthetic pathway for 1 and 2 was discussed. Compounds 1 and 2 showed inhibitory activity against the pathogenic fungus Alternaria brassicae.

Sesquiterpene furan compound CJ-01, a novel chitin synthase 2 inhibitor from Chloranthus japonicus SIEB.

PubMed

Yim, Nam Hui; Hwang, Eui Il; Yun, Bong Sik; Park, Ki Duk; Moon, Jae Sun; Lee, Sang Han; Sung, Nack Do; Kim, Sung Uk

2008-05-01

A novel sesquiterpene furan compound CJ-01 was isolated from the methanol extract of the whole plant of Chloranthus japonicus SIEB. by monitoring the inhibitory activity of chitin synthase 2 from Saccharomyces cerevisiae. Based on spectroscopic analysis, the structure of compound CJ-01 was determined as 3,4,8a-trimethyl-4a,7,8,8a-tetrahydro-4a-naphto[2,3-b]furan-9-one. The compound inhibited chitin synthase 2 of Saccharomyces cerevisiae in a dose-dependent manner with an IC50 of 39.6 microg/ml, whereas it exhibited no inhibitory activities against chitin synthase 1 and 3 of S. cerevisiae up to 280 microg/ml. CJ-01 has 1.7-fold stronger inhibitory activity than polyoxin D (IC50=70 microg/ml), a well-known chitin synthase inhibitor. These results indicate that the compound is a specific inhibitor of chitin synthase 2 from S. cerevisiae. In addition, CJ-01 showed antifungal activities against various human and phytopathogenic fungi. Therefore, the compound might be an interesting lead to develop effective antifungal agents.

Supercritical water oxidation of dioxins and furans in waste incinerator fly ash, sewage sludge and industrial soil.

PubMed

Zainal, Safari; Onwudili, Jude A; Williams, Paul T

2014-08-01

Three environmental samples containing dioxins and furans have been oxidized in the presence of hydrogen peroxide under supercritical water oxidation conditions. The samples consisted of a waste incinerator fly ash, sewage sludge and contaminated industrial soil. The reactor system was a batch, autoclave reactor operated at temperatures between 350 degrees C and 450degrees C, corresponding to pressures of approximately 20-33.5 MPa and with hydrogen peroxide concentrations from 0.0 to 11.25 vol%. Hydrogen peroxide concentration and temperature/pressure had a strong positive effect on the oxidation of dioxins and furans. At the highest temperatures and pressure of supercritical water oxidation of 4500C and 33.5 MPa and with 11.25 vol% of hydrogen peroxide, the destruction efficiencies of the individual polychlorinated dibenzo-p-dioxins/polychlorinated dibenzofurans (PCDD/PCDF) isomers were between 90% and 99%. There did not appear to be any significant differences in the PCDD/PCDF destruction efficiencies in relation to the different sample matrices of the waste incinerator fly ash, sewage sludge and contaminated industrial soil.

Simultaneous detoxification and bioethanol fermentation of furans-rich synthetic hydrolysate by digestate-based pyrochar.

PubMed

Sambusiti, C; Monlau, F; Antoniou, N; Zabaniotou, A; Barakat, A

2016-12-01

Pyrolysis is a sustainable pathway to transform renewable biomasses into both biofuels and advanced carbonaceous materials (i.e. pyrochar) which can be used as adsorbent of furan compounds. In particular, the aim of this study was to: i) evaluate the effect of vibro-ball milling on physical characteristics of pyrochar and its consequent performance on solely detoxification of a synthetic medium, containing furans and soluble sugars; ii) study the simultaneous detoxification and bioethanol fermentation, by adding activated pyrochar into fermentation medium. Results demonstrated that, compared to untreated pyrochar, the use of milled pyrochar increased by 52% furfural removal from the synthetic medium. Furfural removal rate was also increased (adsorption kinetic constant increased from 0.015 min -1 up to 0.215 min -1 ), at a pyrochar loading of 40 g L -1 . Although, the simultaneous addition of pyrochar into the fermentation medium did not improve the bioethanol yield of the synthetic medium, it has significantly increased the bioethanol production rate. Copyright © 2016 Elsevier Ltd. All rights reserved.

Furan-2-ylmethylene thiazolidinediones as novel, potent, and selective inhibitors of phosphoinositide 3-kinase gamma.

PubMed

Pomel, Vincent; Klicic, Jasna; Covini, David; Church, Dennis D; Shaw, Jeffrey P; Roulin, Karen; Burgat-Charvillon, Fabienne; Valognes, Delphine; Camps, Montserrat; Chabert, Christian; Gillieron, Corinne; Françon, Bernard; Perrin, Dominique; Leroy, Didier; Gretener, Denise; Nichols, Anthony; Vitte, Pierre Alain; Carboni, Susanna; Rommel, Christian; Schwarz, Matthias K; Rückle, Thomas

2006-06-29

Class I phosphoinositide 3-kinases (PI3Ks), in particular PI3Kgamma, have become attractive drug targets for inflammatory and autoimmune diseases. Here, we disclose a novel series of furan-2-ylmethylene thiazolidinediones as selective, ATP-competitive PI3Kgamma inhibitors. Structure-based design and X-ray crystallography of complexes formed by inhibitors bound to PI3Kgamma identified key pharmacophore features for potency and selectivity. An acidic NH group on the thiazolidinedione moiety and a hydroxy group on the furan-2-yl-phenyl part of the molecule play crucial roles in binding to PI3K and contribute to class IB PI3K selectivity. Compound 26 (AS-252424), a potent and selective small-molecule PI3Kgamma inhibitor emerging from these efforts, was further profiled in three different cellular PI3K assays and shown to be selective for class IB PI3K-mediated cellular effects. Oral administration of 26 in a mouse model of acute peritonitis led to a significant reduction of leukocyte recruitment.

Direct carbon-carbon coupling of furanics with acetic acid over Bronsted zeolites

DOE PAGES

Gumidyala, Abhishek; Wang, Bin; Crossley, Steven

2016-09-16

Effective carbon-carbon coupling of acetic acid to form larger products while minimizing CO 2 emissions is critical to achieving a step change in efficiency for the production of transportation fuels from sustainable biomass. Here, we report the direct acylation of methylfuran with acetic acid in the presence ofwater, all ofwhich can be readily produced from biomass. This direct coupling limits unwanted polymerization of furanics while producing acetyl methylfuran. Reaction kinetics and density functional theory calculations illustrate that the calculated apparent barrier for the dehydration of the acid to form surface acyl species is similar to the experimentally measured barrier, implyingmore » that this step plays a significant role in determining the net reaction rate. Water inhibits the overall rate, but selectivity to acylated products is not affected.We show that furanic species effectively stabilize the charge of the transition state, therefore lowering the overall activation barrier. These results demonstrate a promising new route to C–C bond–forming reactions for the production of higher-value products from biomass.« less

Effect of Furan Fatty Acids and 3-Methyl-2,4-nonanedione on Light-Induced Off-Odor in Soybean Oil.

PubMed

Sano, Takashi; Okabe, Ryo; Iwahashi, Maiko; Imagi, Jun; Sato, Toshiro; Yamashita, Toshiyuki; Fukusaki, Eiichiro; Bamba, Takeshi

2017-03-15

Soybean oil is one of the most widely consumed vegetable oils. However, under photooxidative conditions, this oil develops a beany and green off-odor through a mechanism that has not yet been elucidated. Upon photooxidation, 3-methyl-2,4-nonanedione (3-MND) produces a strong aroma. In this study, the effect of furan fatty acids and 3-MND on odor reversion in soybean oil was investigated. Our findings suggest that the observed light-induced off-odor was likely attributable to the furan fatty acids present in the oil through the generation of 3-MND. While 3-MND may not be directly responsible for the development of light-induced off-odor, this compound appears to be involved because off-odor was detected in canola oil samples containing added 3-MND. In addition, in the present work, 3-hydroxy-3-methyl-2,4-nonanedione, which is derived from 3-MND, was identified for the first time in light-exposed soybean oil and shown to be one of the compounds responsible for odor reversion.

Quantification of furanic compounds in coated deep-fried products simulating normal preparation and consumption: optimisation of HS-SPME analytical conditions by response surface methodology.

PubMed

Pérez-Palacios, T; Petisca, C; Melo, A; Ferreira, I M P L V O

2012-12-01

The validation of a method for the simultaneous quantification of furanic compounds in coated deep-fried samples processed and handled as usually consumed is presented. The deep-fried food was grinded using a device that simulates the mastication, and immediately analysed by headspace solid phase microextraction coupled to gas chromatography-mass spectrometry. Parameters affecting the efficiency of HS-SPME procedure were selected by response surface methodology, using a 2(3) full-factorial central composite design. Optimal conditions were achieved using 2g of sample, 3g of NaCl and 40min of absorption time at 37°C. Consistency between predicted and experimented values was observed and quality parameters of the method were established. As a result, furan, 2-furfural, furfuryl alcohol and 2-pentylfuran were, for the first time, simultaneously detected and quantified (5.59, 0.27, 10.48 and 1.77μgg(-1) sample, respectively) in coated deep-fried fish, contributing to a better understanding of the amounts of these compounds in food. Copyright © 2012 Elsevier Ltd. All rights reserved.

Ecotoxicology of organic contaminants to amphibians

USGS Publications Warehouse

Sparling, D.W.; Sparling, Donald W.; Linder, Greg L.; Bishop, Christine A.

2000-01-01

The effects of organic contaminants on amphibians are poorly known but of considerable interest. These contaminants include the highly toxic dioxins and furans as well as PCBs, PAHs and organochlorine pesticides. Although these compounds may have lower acute toxicity than dioxins and furans, they have been implicated in several problems associated with genotoxicity, endocrine disruption, malformations and reduced growth. There is evidence that amphibian tadpoles bioaccumulate these organic compounds and may have biological concentrating factors ranging in the hundreds. This chapter reviews what is known about the effects and concentrations of organic contaminants in amphibians and provides recommendations for further research

One-step catalytic conversion of biomass-derived carbohydrates to liquid fuels

DOEpatents

Sen, Ayusman; Yang, Weiran

2014-03-18

The invention relates to a method for manufacture of hydrocarbon fuels and oxygenated hydrocarbon fuels such as alkyl substituted tetrahydrofurans such as 2,5-dimethyltetrahydrofuran, 2-methyltetrahydrofuran, 5-methylfurfural and mixtures thereof. The method generally entails forming a mixture of reactants that includes carbonaceous material, water, a metal catalyst and an acid reacting that mixture in the presence of hydrogen. The reaction is performed at a temperature and for a time sufficient to produce a furan type hydrocarbon fuel. The process may be adapted to provide continuous manufacture of hydrocarbon fuels such as a furan type fuel.

1,3-Bis[(5-amino-furan-2-yl)meth-yl]-3,4,5,6-tetra-hydro-pyrimidin-1-ium hexa-fluoro-phosphate.

PubMed

Akkurt, Mehmet; Akkoç, Senem; Gök, Yetkin; Tahir, Muhammad Nawaz

2013-01-01

The asymmetric unit of the title salt, C16H21N2O2 (+)·PF6 (-), contains half of the whole ion pair, which has crystallographic mirror symmetry. Two F atoms related by the mirror plane are disordered over two sites of equal occupancy. The dihedral angle between the central ring and the furan ring is 59.3 ()°. In the crystal, the anions and cations are linked through C-H⋯F inter-actions, forming a three-dimensional network.

Brönsted Acid-Catalyzed One-Pot Synthesis of Indoles from o-Aminobenzyl Alcohols and Furans

PubMed Central

Kuznetsov, Alexey; Makarov, Anton; Rubtsov, Alexandr E.; Butin, Alexander V.; Gevorgyan, Vladimir

2013-01-01

Brönsted acid-catalyzed one-pot synthesis of indoles from o-aminobenzyl alcohols and furans has been developed. This method operates via the in situ formation of aminobenzylfuran, followed by its recyclization into the indole core. The method proved to be efficient for substrates possessing different functional groups, including -OMe, -CO2Cy, and -Br. The resulting indoles can easily be transformed into diverse scaffolds, including 2,3- and 1,2-fused indoles, and indole possessing an α,β-unsaturated ketone moiety at the C-2 position. PMID:24255969

Removal of dioxins and furans from flue gases by non-flammable adsorbents in a fixed bed.

PubMed

Fell, H J; Tuczek, M

1998-01-01

The presented adsorption--process KOMBISORBON is applied for high efficient off-gas purification, preferably of polychlorinated dioxins and furans from off-gas of incineration plants, which are generated, when these are operated under unfavourable conditions [2]. This off-gas purification process complies with german laws, which limit the concentration of these substances to less than 0.1 ng toxicity equivalents (TE) per cubic metre of gas [1]. The adsorbent, the adsorption process and its plant concept (fixed bed) is described in detail including economics and obtained operation results. Alternative removal technologies are briefly outlined.

Expression of an Intestine-Specific Transcription Factor (CDX1) in Intestinal Metaplasia and in Subsequently Developed Intestinal Type of Cholangiocarcinoma in Rat Liver

PubMed Central

Ren, Ping; Silberg, Debra G.; Sirica, Alphonse E.

2000-01-01

CDX1 is a caudal-type homeobox intestine-specific transcription factor that has been shown to be selectively expressed in epithelial cells in intestinal metaplasia of the human stomach and esophagus and variably expressed in human gastric and esophageal adenocarcinomas (Silberg DG, Furth EE, Taylor JK, Schuck T, Chiou T, Traber PG: Gastroenterology 1997, 113: 478–486). Through the use of immunohistochemistry and Western blotting, we investigated whether CDX1 is also uniquely associated with the intestinal metaplasia associated with putative precancerous cholangiofibrosis induced in rat liver during furan cholangiocarcinogenesis, as well as expressed in neoplastic glands in a subsequently developed intestinal type of cholangiocarcinoma. In normal, control adult rat small intestine, specific nuclear immunoreactivity for CDX1 was most prominent in enterocytes lining the crypts. In comparison, epithelium from intestinal metaplastic glands within furan-induced hepatic cholangiofibrosis and neoplastic epithelium from later developed primary intestinal-type cholangiocarcinoma each demonstrated strong nuclear immunoreactivity for CDX1. CDX1-positive cells were detected in hepatic cholangiofibrotic tissue as early as 3 weeks after the start of chronic furan treatment. We further determined that the percentages of CDX1-positive neoplastic glands and glandular nuclei are significantly higher in primary tumors than in a derived, transplantable cholangiocarcinoma serially-propagated in vivo. Western blotting confirmed our immunohistochemical results, and no CDX1 immunoreactivity was detected in normal adult rat liver or in hyperplastic biliary epithelial cells. These findings indicate that CDX1 is specifically associated with early intestinal metaplasia and a later developed intestinal-type of cholangiocarcinoma induced in the liver of furan-treated rats. PMID:10666391

Expression of an intestine-specific transcription factor (CDX1) in intestinal metaplasia and in subsequently developed intestinal type of cholangiocarcinoma in rat liver.

PubMed

Ren, P; Silberg, D G; Sirica, A E

2000-02-01

CDX1 is a caudal-type homeobox intestine-specific transcription factor that has been shown to be selectively expressed in epithelial cells in intestinal metaplasia of the human stomach and esophagus and variably expressed in human gastric and esophageal adenocarcinomas (Silberg DG, Furth EE, Taylor JK, Schuck T, Chiou T, Traber PG: Gastroenterology 1997, 113: 478-486). Through the use of immunohistochemistry and Western blotting, we investigated whether CDX1 is also uniquely associated with the intestinal metaplasia associated with putative precancerous cholangiofibrosis induced in rat liver during furan cholangiocarcinogenesis, as well as expressed in neoplastic glands in a subsequently developed intestinal type of cholangiocarcinoma. In normal, control adult rat small intestine, specific nuclear immunoreactivity for CDX1 was most prominent in enterocytes lining the crypts. In comparison, epithelium from intestinal metaplastic glands within furan-induced hepatic cholangiofibrosis and neoplastic epithelium from later developed primary intestinal-type cholangiocarcinoma each demonstrated strong nuclear immunoreactivity for CDX1. CDX1-positive cells were detected in hepatic cholangiofibrotic tissue as early as 3 weeks after the start of chronic furan treatment. We further determined that the percentages of CDX1-positive neoplastic glands and glandular nuclei are significantly higher in primary tumors than in a derived, transplantable cholangiocarcinoma serially-propagated in vivo. Western blotting confirmed our immunohistochemical results, and no CDX1 immunoreactivity was detected in normal adult rat liver or in hyperplastic biliary epithelial cells. These findings indicate that CDX1 is specifically associated with early intestinal metaplasia and a later developed intestinal-type of cholangiocarcinoma induced in the liver of furan-treated rats.

Detection of 5-hydroxymethylfurfural and furfural in the aerosol of electronic cigarettes.

PubMed

Soussy, Sarah; El-Hellani, Ahmad; Baalbaki, Rima; Salman, Rola; Shihadeh, Alan; Saliba, Najat A

2016-11-01

The wide availability of sweet flavours has been hypothesised as a factor in the popularity of electronic cigarette (ECIG), especially among youth. Saccharides, which are commonly used to impart a sweet flavour to ECIG liquids, thermally degrade to produce toxic compounds, like aldehydes and furans. This study investigates the formation of furanic compounds in aerosols when ECIG liquid solutions of varying sweetener concentrations are vaped under different power and puff duration. Liquids are prepared by mixing aqueous sucrose, glucose or sorbitol solutions to a 70/30 propylene glycol/glycerin solution. Aerosols are generated and trapped on filter pads using a commercially available ECIG operating at 4.3 and 10.8 W and 4 and 8 s puff duration. Extraction, elimination of matrix interference and quantification are achieved using novel solid phase extraction and gas chromatography tandem mass spectrometry methods (GC-MS). Well-resolved GC peaks of 5-hydroxymethylfurfural (HMF) and furfural (FA) are detected. Both HMF and FA are quantified in the aerosols of sweet-flavoured e-liquids under various vaping conditions. Levels of furan emissions are significantly correlated with electric power and sweetener concentration and not with puff duration. Unlike saccharides, the formation of HMF and FA from a sugar alcohol is negligible. The addition of sweeteners to ECIG liquids exposes ECIG user to furans, a toxic class of compounds. Under certain conditions, the per-puff yield of HMF and FA in ECIG emissions is comparable to values reported for combustible cigarettes. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Method of making thermally removable adhesives

DOEpatents

Aubert, James H.

2004-11-30

A method of making a thermally-removable adhesive is provided where a bismaleimide compound, a monomeric furan compound, containing an oxirane group an amine curative are mixed together at an elevated temperature of greater than approximately 90.degree. C. to form a homogeneous solution, which, when cooled to less than approximately 70.degree. C., simultaneously initiates a Diels-Alder reaction between the furan and the bismaleimide and a epoxy curing reaction between the amine curative and the oxirane group to form a thermally-removable adhesive. Subsequent heating to a temperature greater than approximately 100.degree. C. causes the adhesive to melt and allows separation of adhered pieces.

Alternating phenylene and furan/pyrrole/thiophene units-based oligomers: A computational study of the structures and optoelectronic properties

NASA Astrophysics Data System (ADS)

Sahu, Harikrishna; Shukla, Rishabh; Goswami, Juri; Gaur, Priyank; Panda, Aditya N.

2018-01-01

Structural and optoelectronic properties of phenylene-furan, phenylene-pyrrole and phenylene-thiophene oligomers are reported using density functional theory methods. Studies reveal that stabilities of conformers change with increasing chain length, and helical conformers are energetically feasible for large oligomers of the studied systems, due to stacking interactions between adjacent helical turns. Absorption spectra of helices are dominated by multiple number of electronic transitions other than the S0 →S1 , involving orbitals other than the HOMO/LUMO. All studied helices are optically active having similar pattern of negative and positive peaks in the CD spectra.

Characterization of Emissions Produced by the Open Burning/Open Detonation of Complex Munitions

DTIC Science & Technology

1996-09-01

Picoline I ,4-Naphthoquinone N-Nitrosomethylethylamnine 1.3 -Dinitrobenzene Methyl methanesulfonate Pentachi orobenzene N-Nitrosodi ethyl amine 1... Chromium Zinc Copper 3.2.6 Particulate Matter Less Than Ten Microns in Diameter (PM10) 3.2.7 Dioxins and Furans The analysis for dioxins and furans...6.24e-04 2.09e-03 Chromium 5.69e-06 4.19e-06 3.2 1e-06 4.36e-06 1.25e-06 -5.06e-06 Copper 1.74e-04 1.03e-04 7.16e-05 1. 16e-04 5.23e-05 1.95e-04 Lead

Method of making thermally removable polymeric encapsulants

DOEpatents

Small, James H.; Loy, Douglas A.; Wheeler, David R.; McElhanon, James R.; Saunders, Randall S.

2001-01-01

A method of making a thermally-removable encapsulant by heating a mixture of at least one bis(maleimide) compound and at least one monomeric tris(furan) or tetrakis(furan) compound at temperatures from above room temperature to less than approximately 90.degree. C. to form a gel and cooling the gel to form the thermally-removable encapsulant. The encapsulant can be easily removed within approximately an hour by heating to temperatures greater than approximately 90.degree. C., preferably in a polar solvent. The encapsulant can be used in protecting electronic components that may require subsequent removal of the encapsulant for component repair, modification or quality control.

2,3,5-Substituted tetrahydrofurans: COX-2 inhibitory activities of 5-hydroxymethyl-/carboxyl-2,3-diaryl-tetrahydro-furan-3-ols.

PubMed

Singh, Palwinder; Mittal, Anu; Kaur, Satwinderjeet; Kumar, Subodh

2008-12-01

5-Hydroxymethyl-/carboxyl-2,3-diaryl-tetrahydro-furan-3-ols have been investigated for their COX-1 and COX-2 inhibitory activities. Compounds 17, 18 and 20 have been identified as showing appreciable COX-2 inhibition and selectivity. The group present at C-5 of tetrahydrofuran and the substituents at the two phenyl rings, through their interactions with active site amino acid residues, significantly affect the activities of these molecules. The quantitative structure-activity relationship studies indicate the role of logP, TPSA, molecular connectivity and valence connectivity towards the activities of these molecules.

An experimental and kinetic investigation of premixed furan/oxygen/argon flames

PubMed Central

Tian, Zhenyu; Yuan, Tao; Fournet, Rene; Glaude, Pierre-Alexandre; Sirjean, Baptiste; Battin-Leclerc, Frédérique; Zhang, Kuiwen; Qi, Fei

2013-01-01

The detailed chemical structures of three low-pressure (35 Torr) premixed laminar furan/oxygen/argon flames with equivalence ratios of 1.4, 1.8 and 2.2 have been investigated by using tunable synchrotron vacuum ultraviolet (VUV) photoionization and molecular-beam mass spectrometry. About 40 combustion species including hydrocarbons and oxygenated intermediates have been identified by measurements of photoionization efficiency spectra. Mole fraction profiles of the flame species including reactants, intermediates and products have been determined by scanning burner position with some selected photon energies near ionization thresholds. Flame temperatures have been measured by a Pt-6%Rh/Pt-30%Rh thermocouple. A new mechanism involving 206 species and 1368 reactions has been proposed whose predictions are in reasonable agreement with measured species profiles for the three investigated flames. Rate-of-production and sensitivity analyses have been performed to track the key reaction paths governing furan consumption for different equivalence ratios. Both experimental and modeling results indicate that few aromatics could be formed in these flames. Furthermore, the current model has been validated against previous pyrolysis results of the literature obtained behind shock waves and the agreement is reasonable as well. PMID:23814311

An experimental and kinetic investigation of premixed furan/oxygen/argon flames.

PubMed

Tian, Zhenyu; Yuan, Tao; Fournet, Rene; Glaude, Pierre-Alexandre; Sirjean, Baptiste; Battin-Leclerc, Frédérique; Zhang, Kuiwen; Qi, Fei

2011-04-01

The detailed chemical structures of three low-pressure (35 Torr) premixed laminar furan/oxygen/argon flames with equivalence ratios of 1.4, 1.8 and 2.2 have been investigated by using tunable synchrotron vacuum ultraviolet (VUV) photoionization and molecular-beam mass spectrometry. About 40 combustion species including hydrocarbons and oxygenated intermediates have been identified by measurements of photoionization efficiency spectra. Mole fraction profiles of the flame species including reactants, intermediates and products have been determined by scanning burner position with some selected photon energies near ionization thresholds. Flame temperatures have been measured by a Pt-6%Rh/Pt-30%Rh thermocouple. A new mechanism involving 206 species and 1368 reactions has been proposed whose predictions are in reasonable agreement with measured species profiles for the three investigated flames. Rate-of-production and sensitivity analyses have been performed to track the key reaction paths governing furan consumption for different equivalence ratios. Both experimental and modeling results indicate that few aromatics could be formed in these flames. Furthermore, the current model has been validated against previous pyrolysis results of the literature obtained behind shock waves and the agreement is reasonable as well.

Thermoreversibly Cross-Linked EPM Rubber Nanocomposites with Carbon Nanotubes

PubMed Central

Criscitiello, Francesco; van Essen, Machiel; Araya-Hermosilla, Rodrigo; Migliore, Nicola; Lenti, Mattia; Raffa, Patrizio

2018-01-01

Conductive rubber nanocomposites were prepared by dispersing conductive nanotubes (CNT) in thermoreversibly cross-linked ethylene propylene rubbers grafted with furan groups (EPM-g-furan) rubbers. Their features were studied with a strong focus on conductive and mechanical properties relevant for strain-sensor applications. The Diels-Alder chemistry used for thermoreversible cross-linking allows for the preparation of fully recyclable, homogeneous, and conductive nanocomposites. CNT modified with compatible furan groups provided nanocomposites with a relatively large tensile strength and small elongation at break. High and low sensitivity deformation experiments of nanocomposites with 5 wt % CNT (at the percolation threshold) displayed an initially linear sensitivity to deformation. Notably, only fresh samples displayed a linear response of their electrical resistivity to deformations as the resistance variation collapsed already after one cycle of elongation. Notwithstanding this mediocre performance as a strain sensor, the advantages of using thermoreversible chemistry in a conductive rubber nanocomposite were highlighted by demonstrating crack-healing by welding due to the joule effect on the surface and the bulk of the material. This will open up new technological opportunities for the design of novel strain-sensors based on recyclable rubbers. PMID:29360772

Substituent effects on the relaxation dynamics of furan, furfural and β-furfural: a combined theoretical and experimental approach.

PubMed

Oesterling, Sven; Schalk, Oliver; Geng, Ting; Thomas, Richard D; Hansson, Tony; de Vivie-Riedle, Regina

2017-01-18

For the series furan, furfural and β-furfural we investigated the effect of substituents and their positioning on the photoinduced relaxation dynamics in a combined theoretical and experimental approach. Using time resolved photoelectron spectroscopy with a high intensity probe pulse, we can, for the first time, follow the whole deactivation process of furan through a two photon probe signal. Using the extended 2-electron 2-orbital model [Nenov et al., J. Chem. Phys., 2011, 135, 034304] we explain the formation of one central conical intersection and predict the influence of the aldehyde group of the derivatives on its geometry. This, as well as the relaxation mechanisms from photoexcitation to the final outcome was investigated using a variety of theoretical methods. Complete active space self consistent field was used for on-the-fly calculations while complete active space perturbation theory and coupled cluster theory were used to accurately describe critical configurations. Experiment and theory show the relaxation dynamics of furfural and β-furfural to be slowed down, and together they disclose an additional deactivation pathway, which is attributed to the n O lonepair state introduced with the aldehyde group.

Naphtho[1,2-b]furan-4,5-dione is a potent anti-MRSA agent against planktonic, biofilm and intracellular bacteria.

PubMed

Yang, Shih-Chun; Yen, Feng-Lin; Wang, Pei-Wen; Aljuffali, Ibrahim A; Weng, Yi-Han; Tseng, Chih-Hua; Fang, Jia-You

2017-09-01

Naphtho[1,2-b]furan-4,5-dione (N12D) and naphtho[2,3-b]furan-4,9-dione (N23D) are furanonaphthoquinone derivatives from natural resources. We examined the antimicrobial activity of N12D and N23D against drug-resistant Staphylococcus aureus. Minimum inhibitory concentration, minimum bactericidal concentration, bacterial viability and agar diffusion assay were conducted against methicillin-resistant S. aureus (MRSA) and clinical isolates of vancomycin-resistant S. aureus. The minimum inhibitory concentration of N12D and N23D against MRSA was 4.9-9.8 and 39 μM, respectively. With regard to the agar diffusion test, the inhibition zone of the quinone compounds was threefold larger than that of oxacillin. N12D was found to inhibit MRSA biofilm thickness from 24 to 16 μm as observed by confocal microscopy. N12D showed a significant reduction of the intracellular MRSA burden without decreasing the macrophage viability. The antibacterial mechanisms of N12D may be bacterial wall/membrane damage and disturbance of gluconeogenesis and the tricarboxylic acid cycle.

An efficient method for the simultaneous determination of furan, 2-methylfuran and 2-pentylfuran in fruit juices by headspace solid phase microextraction and gas chromatography-flame ionisation detector.

PubMed

Hu, Gaofei; Zhu, Yan; Hernandez, Marta; Koutchma, Tatiana; Shao, Suqin

2016-02-01

A headspace solid phase microextraction (HS-SPME) procedure followed by gas chromatography-flame ionisation detector (GC-FID) analysis was developed and validated for the simultaneous analysis of furan, 2-methylfuran and 2-pentylfuran from juice samples. Extraction at 32 °C for 20 min with stirring at 600 rpm and NaCl concentration 15% (W/V) was the optimal HS-SPME condition for all the three compounds by using a carboxen/polydimethylsiloxane fused silica fibre (75 μm). The extracted compounds were base line separated on a SPB-1 GC column within 12 min. The relative standard deviations of all analytes were less than 6.7%. The recovery rates were between 90.2% and 110.1%. The limits of detection and limits of quantification were 0.056-0.23 ng/mL and 0.14-0.76 ng/mL, respectively. The results showed that the developed method was sensitive, precise, accurate and robust for the determination of furan, 2-methylfuran and 2-pentylfuran in complex matrices without interferences from other components. Crown Copyright © 2015. Published by Elsevier Ltd. All rights reserved.

Catalytic Hydrodeoxygenation of High Carbon Furylmethanes to Renewable Jet-fuel Ranged Alkanes over a Rhenium-Modified Iridium Catalyst.

PubMed

Liu, Sibao; Dutta, Saikat; Zheng, Weiqing; Gould, Nicholas S; Cheng, Ziwei; Xu, Bingjun; Saha, Basudeb; Vlachos, Dionisios G

2017-08-24

Renewable jet-fuel-range alkanes are synthesized by hydrodeoxygenation of lignocellulose-derived high-carbon furylmethanes over ReO x -modified Ir/SiO 2 catalysts under mild reaction conditions. Ir-ReO x /SiO 2 with a Re/Ir molar ratio of 2:1 exhibits the best performance, achieving a combined alkanes yield of 82-99 % from C 12 -C 15 furylmethanes. The catalyst can be regenerated in three consecutive cycles with only about 12 % loss in the combined alkanes yield. Mechanistically, the furan moieties of furylmethanes undergo simultaneous ring saturation and ring opening to form a mixture of complex oxygenates consisting of saturated furan rings, mono-keto groups, and mono-hydroxy groups. Then, these oxygenates undergo a cascade of hydrogenolysis reactions to alkanes. The high activity of Ir-ReO x /SiO 2 arises from a synergy between Ir and ReO x , whereby the acidic sites of partially reduced ReO x activate the C-O bonds of the saturated furans and alcoholic groups while the Ir sites are responsible for hydrogenation with H 2 . © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Impact of furan derivatives and phenolic compounds on hydrogen production from organic fraction of municipal solid waste using co-culture of Enterobacter aerogenes and E. coli.

PubMed

Sharma, Preeti; Melkania, Uma

2017-09-01

In the present study, the effect of furan derivatives (furfural and 5-hydroxymethylfurfural) and phenolic compounds (vanillin and syringaldehyde) on hydrogen production from organic fraction of municipal solid waste (OFMSW) was investigated using co-culture of facultative anaerobes Enterobacter aerogenes and E. coli. The inhibitors were applied in the concentration ranges of 0.25, 0.5, 1, 2 and 5g/L each. Inhibition coefficients of phenolic compounds were higher than those of furan derivatives and vanillin exhibited maximum inhibition coefficients correspondingly lowest hydrogen yield among all inhibitors. Furfural and 5-hydroxymethylfurfural addition resulted in an average decrease of 26.99% and 37.16% in hydrogen yield respectively, while vanillin and syringaldehyde resulted in 49.40% and 42.26% average decrease in hydrogen yield respectively. Further analysis revealed that Furfural and 5-hydroxymethylfurfural were completely degraded up to concentrations of 1g/L, while vanillin and syringaldehyde were degraded completely up to the concentration of 0.5g/L. Volatile fatty acid generation decreased with inhibitors addition. Copyright © 2017 Elsevier Ltd. All rights reserved.

Crystal structures of fac-tri-carbonyl-chlorido-(6,6'-dihy-droxy-2,2'-bi-pyridine)-rhenium(I) tetra-hydro-furan monosolvate and fac-bromido-tricarbon-yl(6,6'-dihy-droxy-2,2'-bi-pyridine)-manganese(I) tetra-hydro-furan monosolvate.

PubMed

Lense, Sheri; Piro, Nicholas A; Kassel, Scott W; Wildish, Andrew; Jeffery, Brent

2016-08-01

The structures of two facially coordinated Group VII metal complexes, fac-[ReCl(C10H8N2O2)(CO)3]·C4H8O (I·THF) and fac-[MnBr(C10H8N2O2)(CO)3]·C4H8O (II·THF), are reported. In both complexes, the metal ion is coordinated by three carbonyl ligands, a halide ligand, and a 6,6'-dihy-droxy-2,2'-bi-pyridine ligand in a distorted octa-hedral geometry. Both complexes co-crystallize with a non-coordinating tetra-hydro-furan (THF) solvent mol-ecule and exhibit inter-molecular but not intra-molecular hydrogen bonding. In both crystal structures, chains of complexes are formed due to inter-molecular hydrogen bonding between a hy-droxy group from the 6,6'-dihy-droxy-2,2'-bi-pyridine ligand and the halide ligand from a neighboring complex. The THF mol-ecule is hydrogen bonded to the remaining hy-droxy group.

Template engineered biopotent macrocyclic complexes involving furan moiety: Molecular modeling and molecular docking

NASA Astrophysics Data System (ADS)

Rathi, Parveen; Singh, D. P.

2015-08-01

Bioactive cobalt(II), nickel(II), copper(II) and zinc(II) complexes of octaazamacrocycle, 19, 20-dioxa-2,3,5,6,11,12,14,15-octaazatricyclo[14.2.1.1]icosa-1,6,8,10,15,17-hexaene-4,13-dithione, derived from furan-2,5-dione and thiocarbonohydrazide in the mole ratio 2:2:1 have been engineered via template methodology. The synthesized metal complexes have also been structurally characterized in the light of various physicochemical techniques and evaluated for antimicrobial and antioxidant activities. All these studies point toward the formation of divalent macrocyclic complexes possessing distorted octahedral geometry and having significant antimicrobial and antioxidant properties as compared to the starting precursors. Virtual screening of a representative complex was done through docking to the binding site of COX-2 to evaluate the anti-inflammatory activity of the series. Non-electrolytic nature of the complexes has been predicted on the basis of low value of molar conductivity in DMSO. All the complexes were having notable activities against pathogenic microbes as compared to precursors-thiocarbonohydrazide and furan-2,5-dione however, the complex 5, [Ni (C10H8N8O2S2) (NO3)2], shows the best antimicrobial activity.

Pulsed addition of HMF and furfural to batch-grown xylose-utilizing Saccharomyces cerevisiae results in different physiological responses in glucose and xylose consumption phase

PubMed Central

2013-01-01

Background Pretreatment of lignocellulosic biomass generates a number of undesired degradation products that can inhibit microbial metabolism. Two of these compounds, the furan aldehydes 5-hydroxymethylfurfural (HMF) and 2-furaldehyde (furfural), have been shown to be an impediment for viable ethanol production. In the present study, HMF and furfural were pulse-added during either the glucose or the xylose consumption phase in order to dissect the effects of these inhibitors on energy state, redox metabolism, and gene expression of xylose-consuming Saccharomyces cerevisiae. Results Pulsed addition of 3.9 g L-1 HMF and 1.2 g L-1 furfural during either the glucose or the xylose consumption phase resulted in distinct physiological responses. Addition of furan aldehydes in the glucose consumption phase was followed by a decrease in the specific growth rate and the glycerol yield, whereas the acetate yield increased 7.3-fold, suggesting that NAD(P)H for furan aldehyde conversion was generated by acetate synthesis. No change in the intracellular levels of NAD(P)H was observed 1 hour after pulsing, whereas the intracellular concentration of ATP increased by 58%. An investigation of the response at transcriptional level revealed changes known to be correlated with perturbations in the specific growth rate, such as protein and nucleotide biosynthesis. Addition of furan aldehydes during the xylose consumption phase brought about an increase in the glycerol and acetate yields, whereas the xylitol yield was severely reduced. The intracellular concentrations of NADH and NADPH decreased by 58 and 85%, respectively, hence suggesting that HMF and furfural drained the cells of reducing power. The intracellular concentration of ATP was reduced by 42% 1 hour after pulsing of inhibitors, suggesting that energy-requiring repair or maintenance processes were activated. Transcriptome profiling showed that NADPH-requiring processes such as amino acid biosynthesis and sulfate and nitrogen assimilation were induced 1 hour after pulsing. Conclusions The redox and energy metabolism were found to be more severely affected after pulsing of furan aldehydes during the xylose consumption phase than during glucose consumption. Conceivably, this discrepancy resulted from the low xylose utilization rate, hence suggesting that xylose metabolism is a feasible target for metabolic engineering of more robust xylose-utilizing yeast strains. PMID:24341320

Production of dioxins and furans for various solid fuels burnt in 25 kW automatic boiler

NASA Astrophysics Data System (ADS)

Hopan, František; Horák, Jiří; Krpec, Kamil; Kubesa, Petr; Dej, Milan; Laciok, Vendula

2016-06-01

There has been brown coal, black coal and maize straw in a pellet form burnt in an automatic boiler. Production of dibenzodioxins and dibenzofuranes, recomputated through toxicity equivalents, expressed as the emission factor relative to the fuel unit, has differentiated in a range of ca. three orders (0.05 up to 78.9 ng/kg) in dependence on a sort of the used fuel. The measured values have been compared with emission factors used for the emission inventory in the Czech Republic and Poland and with the emission limit applicable for waste incineration plants. The study has proven the influence of chlorine content in fuel on production of dioxins and furanes.

Crystal structure of 1,2,3,5-di-O-methyl­ene-α-d-xylo­furan­ose

PubMed Central

Tiritiris, Ioannis; Tussetschläger, Stefan; Kantlehner, Willi

2015-01-01

The title compound, C7H10O5, was synthesized by reaction of d-xylose with paraformaldehyde. In the crystal, the central part of the mol­ecule consists of a five-membered C4O ring with an envelope conformation, with the methine C atom adjacent to the O atom being the flap. The protected O atoms of both cyclic acetal groups are oriented so that the four chiral C atoms of the furan­ose part show an R configuration. C—H⋯O hydrogen bonds are present between adjacent mol­ecules, generating a three-dimensional network. PMID:26594582

Vortex- and CO2 -gas-assisted liquid-liquid microextraction with salt addition for the high-performance liquid chromatographic determination of furanic compounds in concentrated juices and dried fruits.

PubMed

Abu-Bakar, Nur-Bahiyah; Makahleh, Ahmad; Saad, Bahruddin

2016-03-01

A novel microextraction method based on vortex- and CO2 -assisted liquid-liquid microextraction with salt addition for the isolation of furanic compounds (5-hydroxymethyl-2-furaldehyde, 5-methyl-2-furaldehyde, 2-furaldehyde, 3-furaldehyde, 2-furoic and 3-furoic acids) was developed. Purging the sample with CO2 was applied after vortexing to enhance the phase separation and mass transfer of the analytes. The optimum extraction conditions were: extraction solvent (volume), propyl acetate (125 μL); sample pH, 2.4; vortexing time, 45 s; salt concentration, 25% w/v and purging time, 5 min. The analytes were separated using an ODS Hypersil C18 column (250×4.6 mm i.d, 5 μm) under gradient flow. The proposed method showed good linearities (r(2) >0.999), low detection limits (0.08-1.9 μg/L) and good recoveries (80.7-122%). The validated method was successfully applied for the determination of the furanic compounds in concentrated juice (mango, date, orange, pomegranate, roselle, mangosteen and soursop) and dried fruit (prune, date and apricot paste) samples. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Emissions of PCDD/Fs, PCBs, and PAHs from a modern diesel engine equipped with catalyzed emission control systems.

PubMed

Laroo, Christopher A; Schenk, Charles R; Sanchez, L James; McDonald, Joseph

2011-08-01

Exhaust emissions of 17 2,3,7,8-substituted chlorinated dibenzo-p-dioxin/furan (CDD/F) congeners, tetra-octa CDD/F homologues, 12 2005 WHO chlorinated biphenyls (CB) congeners, mono-nona CB homologues, and 19 polycyclic aromatic hydrocarbons (PAHs) from a model year 2008 Cummins ISB engine were investigated. Testing included configurations composed of different combinations of aftertreatment including a diesel oxidation catalyst (DOC), catalyzed diesel particulate filter (CDPF), copper zeolite urea selective catalytic reduction (SCR), iron zeolite SCR, and ammonia slip catalyst. Results were compared to a baseline engine out configuration. Testing included the use of fuel that contained the maximum expected chlorine (Cl) concentration of U.S. highway diesel fuel and a Cl level 1.5 orders of magnitude above. Results indicate there is no risk for an increase in polychlorinated dibenzo-p-dioxin/furan and polychlorinated biphenyl emissions from modern diesel engines with catalyzed aftertreatment when compared to engine out emissions for configurations tested in this program. These results, along with PAH results, compare well with similar results from modern diesel engines in the literature. The results further indicate that polychlorinated dibenzo-p-dioxin/furan emissions from modern diesel engines both with and without aftertreatment are below historical values reported in the literature as well as the current inventory value.

Kinetic study of the thermal hydrolysis of Agave salmiana for mezcal production.

PubMed

Garcia-Soto, M J; Jimenez-Islas, H; Navarrete-Bolanos, J L; Rico-Martinez, R; Miranda-Lopez, R; Botello-Alvarez, J E

2011-07-13

The kinetics of the thermal hydrolysis of the fructans of Agave salmiana were determined during the cooking step of mezcal production in a pilot autoclave. Thermal hydrolysis was achieved at different temperatures and cooking times, ranging from 96 to 116 °C and from 20 to 80 h. A simple kinetic model of the depolymerization of fructans to monomers and other reducing sugars and of the degradation of reducing sugars to furans [principally 5-(hydroxymethyl)furfural, HMF] was developed. From this model, the rate constants of the reactions were calculated, as well as the pre-exponential factors and activation energies of the Arrhenius equation. The model was found to fit the experimental data well. The tradeoff between a maximum fructan hydrolysis and a critical furan concentration in allowing for the best ethanol yield during fermentation was investigated. The results indicated that the thermal hydrolysis of agave was optimal, from the point of view of ethanol yield in the ensuing fermentation, in the temperature range of 106-116 °C and the cooking range time of 6-14 h. The optimal conditions corresponded to a fructan hydrolysis of 80%, producing syrups with furan and reducing sugar concentrations of 1 ± 0.1 and 110 ± 10 g/L, respectively.

Influence of heteroatoms on photovoltaic performance of donor–acceptor copolymers based on 2,6-di(thiophen-2-yl)benzo[1,2-b:4,5-b']difurans and diketopyrrolopyrrole

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kobilka, Brandon M.; Hale, Benjamin J.; Ewan, Monique D.

2013-01-01

Donor–acceptor conjugated polymers based on the novel donor 3,7-didodecyl-2,6-di(thiophen-2-yl)benzo[1,2-b:4,5-b']difuran, and 1,4-diketopyrrolo[3,4-c]pyrrole as the acceptor were synthesized via the Stille cross-coupling reaction. The alkyl chains on the diketopyrrolopyrrole monomers were varied to engineer the solubility and morphology of the materials. Thiophene and furan moieties were used to flank the DPP group and the impact of these heterocycles on the polymers' properties evaluated. All of the polymers have similar optoelectronic properties with optical band-gaps of 1.3–1.4 eV, LUMO levels of -3.7 to -3.8 eV and HOMO levels of -5.5 to -5.6 eV. The furan-containing polymers have better solubility than the all-thiophene polymers,more » as significantly higher molecular weight materials of the former were readily dissolved. When the polymers were used as donor materials along with PC71BM as the electron-acceptor in bulk-heterojunction photovoltaic cells, power conversion efficiencies of up to 2.9% were obtained, with the furan-containing polymers giving the best results.« less

Medical surveillance of exposed persons after exposure to PCBs, chlorinated dibenzodioxins and dibenzofurans after PCB transformer or capacitor incidents.

PubMed Central

Schecter, A

1985-01-01

The panel discussion from the perspective of occupational medicine regarding appropriate medical surveillance after a PCB transformer or capacitor incident is reviewed. A thorough occupational medicine history and physical examination is stressed for any worker or other patient who may have been exposed. Appropriate laboratory tests, including complete blood count with differential, serum chemistries, serial blood PCB determinations, fat biopsy to estimate furan and dioxin levels, if indicated, pulmonary function tests, chest X-rays, urinalysis including porphyrin measurement, nerve conduction velocity testing and other tests are discussed. No consensus was reached on recommended length of medical followup. Because the field is rapidly changing, yearly updates of medical protocols are warranted. In addition, the need for surveillance to be conducted by specialists with training and experience in the fields of occupational medicine and nursing was emphasized. It was stressed that measuring the chemicals and their levels in soot and air and then comparing these with the patient's blood or fat levels, in the case of PCBs, furans and dioxins, is vital. It was noted that at present no modality of treatment is known to be clinically efficacious in removing PCBs, furans and dioxins from tissues or blood. PMID:3928362

2-Heteroarylidene-1-indanone derivatives as inhibitors of monoamine oxidase.

PubMed

Nel, Magdalena S; Petzer, Anél; Petzer, Jacobus P; Legoabe, Lesetja J

2016-12-01

In the present study a series of fifteen 2-heteroarylidene-1-indanone derivatives were synthesised and evaluated as inhibitors of recombinant human monoamine oxidase (MAO) A and B. These compounds are structurally related to series of heterocyclic chalcone derivatives which have previously been shown to act as MAO-B specific inhibitors. The results document that the 2-heteroarylidene-1-indanones are in vitro inhibitors of MAO-B, displaying IC 50 values of 0.0044-1.53μM. Although with lower potencies, the derivatives also inhibit the MAO-A isoform with IC 50 values as low as 0.061μM. An analysis of the structure-activity relationships for MAO-B inhibition indicates that substitution with the methoxy group on the A-ring leads to a significant enhancement in MAO-B inhibition compared to the unsubstituted homologues while the effect of the heteroaromatic substituent on activity, in decreasing order is: 5-bromo-2-furan>5-methyl-2-furan>2-pyridine≈2-thiophene>cyclohexyl>3-pyridine≈2-furan. It may therefore be concluded that 2-heteroarylidene-1-indanone derivatives are promising leads for the design of MAO inhibitors for the treatment of Parkinson's disease and possibly other neurodegenerative disorders. Copyright © 2016 Elsevier Inc. All rights reserved.

Cascade Reductive Etherification of Bioderived Aldehydes over Zr-Based Catalysts.

PubMed

Shinde, Suhas; Rode, Chandrashekhar

2017-10-23

An efficient one-pot catalytic cascade sequence has been developed for the production of value-added ethers from bioderived aldehydes. Etherification of 5-(hydroxymethyl)furfural with different aliphatic alcohols over acidic Zr-montmorillonite (Zr-Mont) catalyst produced a mixture of 5-(alkoxymethyl)furfural and 2-(dialkoxymethyl)-5-(alkoxymethyl)furan. The latter was selectively converted back into 5-(alkoxymethyl)furfural by treating it with water over the same catalyst. The synthesis of 2,5-bis(alkoxymethyl)furan was achieved through a cascade sequence involving etherification, transfer hydrogenation, and re-etherification over a combination of acidic Zr-Mont and the charge-transfer hydrogenation catalyst [ZrO(OH) 2 ]. This catalyst combination was further explored for the cascade conversion of 2-furfuraldehyde into 2-(alkoxymethyl)furan. The scope of this strategy was then extended for the reductive etherification of lignin-derived arylaldehydes to obtain the respective benzyl ethers in >80 % yield. Additionally, the mixture of Zr-Mont and ZrO(OH) 2 does not undergo mutual destruction, which was proved by recycling experiments and XRD analysis. Both the catalysts were thoroughly characterized using BET, temperature-programmed desorption of NH 3 and CO 2 , pyridine-FTIR, XRD, inductively coupled plasma optical emission spectroscopy, and X-ray photoelectron spectroscopy techniques. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Inhibitory Effect of Furanic and Phenolic Compounds on Exoelectrogenesis in a Microbial Electrolysis Cell Bioanode

DOE PAGES

Zeng, Xiaofei; Borole, Abhijeet P.; Pavlostathis, Spyros G.

2016-09-09

Furanic and phenolic compounds are 20 lignocellulose-derived compounds known to inhibit to H2- and ethanol- producing microorganisms in dark fermentation. Bioelectrochemical conversion of furanic and phenolic compounds to electricity or H2 has recently been demonstrated as a productive method to use these compounds. However, potential inhibitory effect of furanic and phenolic compounds on exoelectrogenesis in bioelectrochemical systems is not well understood. This study systematically investigated the inhibitory effect of furfural (FF), 5-hydroxymethylfurfural (HMF), syringic acid (SA), vanillic acid (VA), and 4-hydroxybenzoic acid (HBA) on exoelectrogenesis in the bioanode of a microbial electrolysis cell. A mixture of these five compounds atmore » an increasing initial total concentration from 0.8 to 8.0 g/L resulted in current decrease up to 91%. The observed inhibition primarily affected exoelectrogenesis, instead of non-exoelectrogenic biotransformation pathways (e.g., fermentation) of the five compounds. Furthermore, the parent compounds at a high concentration, as opposed to their biotransformation products, were responsible for the observed inhibition. Tests with individual compounds show that all five parent compounds contributed to the observed inhibition by the mixture. The IC50 (concentration resulting in 50% current decrease) was estimated as 2.7 g/L for FF, 3.0 g/L for HMF, 1.9 g/L for SA, 2.1 g/L for VA and 2.0 g/L for HBA. Nevertheless, these compounds below their non-inhibitory concentrations jointly resulted in significant inhibition as a mixture. Catechol and phenol, which were persistent biotransformation products of the mixture, inhibited exoelectrogens at high concentrations, but to a lesser extent than the parent compounds. Recovery of exoelectrogenesis from inhibition by all compounds was observed, except for catechol, which resulted in irreversible inhibition. The reversibility of inhibition, as well as the observed difference in recovery rates, suggest different modes of exoelectrogenesis inhibition, related to the hydrophobicity of the inhibiting compounds.« less

Performance evaluation of a continuous-flow bioanode microbial electrolysis cell fed with furanic and phenolic compounds

DOE PAGES

Zeng, Xiaofei; Borole, Abhijeet P.; Pavlostathis, Spyros G.

2016-07-04

Furanic and phenolic compounds, formed during the pretreatment of lignocellulosic biomass, are problematic byproducts in down-stream biofuel processes. A microbial electrolysis cell (MEC) is an alternative technology to handle furanic and phenolic compounds and produce renewable hydrogen (H 2). In this study, we evaluated the performance of a continuous-flow bioanode MEC fed with furanic and phenolic compounds at different operating conditions. All hydraulic retention times (HRTs) tested (6-24 h) resulted in complete transformation of the parent compounds at an organic loading rate (OLR) of 0.2g L -1 per d and applied voltage of 0.6 V. Increasing the OLR to 0.8more » g L -1 per d at an HRT of 6h resulted in an increased H 2 production rate from 0.07 to 0.14 L L anode 1 per d, but an OLR of 3.2 g L -1 per d did not lead to a higher H 2 production rate. Significant methane production was observed at an OLR of 3.2 g L -1 per d. The lack of increased H 2 production at the highest OLR tested was due to a limited rate of exoelectrogenesis but not fermentation, evidenced by the accumulation of high acetate levels and higher growth of fermenters and methanogens over exoelectrogens. Increasing applied voltage from 0.6 to 1.0V at an OLR of 3.2 g L -1 per d and HRT of 6h enhanced exoelectrogenesis and resulted in a 1.7-fold increase of H 2 production. Under all operating conditions, more than 90% of the biomass was biofilm-associated. Lastly, the present study provides new insights into the performance of continuous-flow bioelectrochemical systems fed with complex waste streams resulting from the pretreatment of lignocellulosic biomass.« less

Synthesis and characterization of poly (benzyl trimethyl ammonium chloride) ionic polymer

NASA Astrophysics Data System (ADS)

Mathew, Manjusha Elizabeth; Ahmad, Ishak; Thomas, Sabu; Daik, Rusli; Kassim, Muhammad

2018-04-01

Poly vinyl benzyl chloride (PVBC) was synthesized by free radical polymerization of 4-vinyl benzyl chloride (VBC) using benzoyl peroxide initiator at 80°C. Amine functionalised polymer prepared by treatment of PVBC with trimethyl amine in different solvents such as water, ethanol, tetra hydro furan(THF) and dimethyl formamide(DMF). The polymers characterized structurally by nuclear magnetic resonance and infrared spectroscopic techniques. The thermal decomposition of the polymer is studied by Thermo Gravimetric Analysis(TGA) and found that the polymer has stability up to 230°C. The nitrogen content of the aminated polymer determined by elemental analysis. The nitrogen content obtained from tetra hydro furan and dimethyl formamide solvents are 20.1% and 19.9% respectively.

Expression of a heat-stable NADPH-dependent alcohol dehydrogenase in Caldicellulosiruptor bescii results in furan aldehyde detoxification

DOE PAGES

Chung, Daehwan; Verbeke, Tobin J.; Cross, Karissa L.; ...

2015-07-22

Compounds such as furfural and 5-hydroxymethylfurfural (5-HMF) are generated through the dehydration of xylose and glucose, respectively, during dilute-acid pretreatment of lignocellulosic biomass and are also potent microbial growth and fermentation inhibitors. The enzymatic reduction of these furan aldehydes to their corresponding, and less toxic, alcohols is an engineering approach that has been successfully implemented in both Saccharomyces cerevisiae and ethanologenicEscherichia coli, but has not yet been investigated in thermophiles relevant to biofuel production through consolidated bioprocessing (CBP). Developing CBP-relevant biocatalysts that are either naturally resistant to such inhibitors, or are amenable to engineered resistance, is therefore, an important componentmore » in making biofuels production from lignocellulosic biomass feasible.« less

Investigation into novel thiophene- and furan-based 4-amino-7-chloroquinolines afforded antimalarials that cure mice.

PubMed

Opsenica, Igor M; Verbić, Tatjana Ž; Tot, Mikloš; Sciotti, Richard J; Pybus, Brandon S; Djurković-Djaković, Olgica; Slavić, Ksenija; Šolaja, Bogdan A

2015-05-01

We herein report the design and synthesis of a novel series of thiophene- and furan-based aminoquinoline derivatives which were found to be potent antimalarials and inhibitors of β-hematin polymerization. Tested compounds were 3-71 times more potent in vitro than CQ against chloroquine-resistant (CQR) W2 strain with benzonitrile 30 being as active as mefloquine (MFQ), and almost all synthesized aminoquinolines (22/27) were more potent than MFQ against multidrug-resistant (MDR) strain C235. In vivo experiments revealed that compound 28 showed clearance with recrudescence at 40 mg/kg/day, while 5/5 mice survived in Thompson test at 160 mg/kg/day. Copyright © 2015 Elsevier Ltd. All rights reserved.

NMR and X-ray structural characterization and conformational aspects of fluorinated (5Z)-3-benzil-5-arylidenofuran-2(5H)-ones

NASA Astrophysics Data System (ADS)

Teixeira, R. R.; Barbosa, L. C. A.; Kabeshov, M. A.; Maltha, C. R. A.; Corrêa, R. S.; Doriguetto, A. C.

2014-10-01

Herein we describe structural insights of (5Z)-3-benzyl-5-(2-fluorobenzylidene)furan-2(5H)-one (6) and (5Z)-3-benzyl-5-(pentafluorobenzylidene)furan-2(5H)-one (7), γ-alkylidenebutenolides analogues of the natural products nostoclides. Their structures were investigated by NMR spectroscopy and X-ray crystallography. The stereochemistry of the exocyclic double bond of these fluorinated compounds was determined to be Z by NMR analysis and confirmed by X-ray data. Compounds 6 and 7 crystallized in the monoclinic crystal system P21/c group. A comparison between structural features of (6) and (7) and nostoclide derivatives previously published by us is described.

Synthesis and film formation of furfuryl- and maleimido carbonic acid derivatives of dextran.

PubMed

Elschner, Thomas; Obst, Franziska; Stana-Kleinschek, Karin; Kargl, Rupert; Heinze, Thomas

2017-04-01

Carbonic acid derivatives of dextran possessing furfuryl- and maleimido moieties were synthesized and processed into thin films by spin coating. First, products with different degrees of substitution (DS) of up to 3.0 and substitution patterns were obtained and characterized by NMR- and FTIR spectroscopy, as well as elemental analysis. Thin films possessing maleimide groups were obtained by spin coating of maleimido dextran (furan-protected) and dextran furfuryl carbamate that was converted with bismaleimide. The removal of the protecting group (furan) on the thin film was monitored by QCM-D and compared with gravimetric analysis of the bulk material. Film morphology and wettability were determined by means of AFM and contact angle measurements. Copyright © 2016 Elsevier Ltd. All rights reserved.

Aerobic Oxidation of 5-(Hydroxymethyl)furfural Cyclic Acetal Enables Selective Furan-2,5-dicarboxylic Acid Formation with CeO2 -Supported Gold Catalyst.

PubMed

Kim, Minjune; Su, Yaqiong; Fukuoka, Atsushi; Hensen, Emiel J M; Nakajima, Kiyotaka

2018-05-14

The utilization of 5-(hydroxymethyl)furfural (HMF) for the large-scale production of essential chemicals has been largely limited by the formation of solid humin as a byproduct, which prevents the operation of stepwise batch-type and continuous flow-type processes. The reaction of HMF with 1,3-propanediol produces an HMF acetal derivative that exhibits excellent thermal stability. Aerobic oxidation of the HMF acetal with a CeO 2 -supported Au catalyst and Na 2 CO 3 in water gives a 90-95 % yield of furan 2,5-dicarboxylic acid, an increasingly important commodity chemical for the biorenewables industry, from concentrated solutions (10-20 wt %) without humin formation. The six-membered acetal ring suppresses thermal decomposition and self-polymerization of HMF in concentrated solutions. Kinetic studies supported by DFT calculations identify two crucial steps in the reaction mechanism, that is, the partial hydrolysis of the acetal into 5-formyl-2-furan carboxylic acid involving OH - and Lewis acid sites on CeO 2 , and subsequent oxidative dehydrogenation of the in situ generated hemiacetal involving Au nanoparticles. These results represent a significant advance over the current state of the art, overcoming an inherent limitation of the oxidation of HMF to an important monomer for biopolymer production. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Organochlorine pesticides, PCBs, dibenzodioxin, and furan concentrations in common snapping turtle eggs (Chelydra serpentina serpentina) in Akwesasne, Mohawk Territory, Ontario, Canada.

PubMed

de Solla, S R; Bishop, C A; Lickers, H; Jock, K

2001-04-01

Subsamples of eight clutches of common snapping turtle eggs (Chelydra serpentina serpentina) were collected from four sites from the territory of the Mohawk Nation, Akwesasne, on the shore of the St. Lawrence River. Egg contents were analyzed for organochlorine pesticides, polychlorinated biphenyls (PCBs), dibenzodioxins, and furans. The sites were 2 to 13 km downstream from PCB-contaminated landfill sites. Maximum concentrations of total PCBs in snapping turtle clutches were extremely high, and ranged from 2 378.2 ng/g to 737 683 ng/g (wet weight) and are among the highest recorded in any tissue of a free-ranging animal. Similarly, in a pooled sample of eggs from all four sites, the summed concentrations of non-ortho PCBs (n = 6 congeners) was also very high at 54.54 ng/g and the summed dioxin and furan concentrations (n = 11 congeners) was 85.8 ng/g. Sum organochlorine pesticide levels varied from 28 to 2,264 ng/g among the four sites. The levels of PCBs found in turtle eggs exceed concentrations associated with developmental problems and reduced hatching success in snapping turtles and other species and also exceed the Canadian tissue residue guidelines for toxic equivalency concentrations. The extremely high levels of organochlorine contaminants demonstrate the high degree of contamination in the environment in the Akwesasne area.

Dioxins, furans, biphenyls, arsenic, thorium and uranium in natural and anthropogenic sources of phosphorus and calcium used in agriculture.

PubMed

Avelar, A C; Ferreira, W M; Pemberthy, D; Abad, E; Amaral, M A

2016-05-01

The aim of this study was to assess the presence of dioxins, furans and biphenyls, and the inorganic contaminants such as arsenic (As), thorium (Th) and uranium (U) in three main products used in Agriculture in Brazil: feed grade dicalcium phosphate, calcined bovine bone meal and calcitic limestone. The first two are anthropogenic sources of phosphorus and calcium, while calcitic limestone is a natural unprocessed mineral. Regarding to dioxin-like substances, all samples analyzed exhibited dioxins (PCDD) and furans (PCDF) and dioxin-like polychlorinated biphenyls (dl-PCBs) concentrations below limit of detection (LOD). In general, achieved is in accordance with regulation in Brazil where is established a maximum limit in limestone used in the citric pulp production (0.50pg WHO-TEQ g(-1)). In addition, reported data revealed very low levels for limestone in comparison with similar materials reported by European legislation. As result for toxic metals, achieved data were obtained using Instrumental Neutron Activation Analysis (INAA). On one hand, limestone sample exhibits the largest arsenic concentration. On another hand, dicalcium phosphate exhibited the largest uranium concentration, which represents a standard in animal nutrition. Therefore, it is phosphorus source in the animal feed industry can be a goal of concern in the feed field. Copyright © 2016 Elsevier B.V. All rights reserved.

Poly(Neopentyl Glycol Furanoate): A Member of the Furan-Based Polyester Family with Smart Barrier Performances for Sustainable Food Packaging Applications

PubMed Central

Munari, Andrea

2017-01-01

In the last decade, there has been an increased interest from the food packaging industry toward the development and application of bioplastics, to contribute to the sustainable economy and to reduce the huge environmental problem afflicting the planet. In the present work, we focus on a new furan-based polyester, poly(neopentyl glycol 2,5-furanoate) (PNF) to be used for sustainable food packaging applications. The aromatic polyester was successfully synthesized with high molecular weight, through a solvent-free process, starting directly from 2,5-furandicarboxylic acid. PNF was revealed to be a material with good thermal stability, characterized by a higher Tg and Tm and a lower RAF fraction compared to poly(propylene 2,5-furanoate) (PPF), ascribable to the two methyl side groups present in PNF glycol-sub-unit. PNF’s mechanical characteristics, i.e., very high elastic modulus and brittle fracture, were found to be similar to those of PPF and PEF. Barrier properties to different gases, temperatures and relative humidity were evaluated. From the results obtained, PNF was showed to be a material with very smart barrier performances, significantly superior with respect to PEF’s ones. Lastly, PNF’s permeability behavior did not appreciably change after contact with food simulants, whereas it got worse with increasing RH, due to the polar nature of furan ring. PMID:28869555

Poly(Neopentyl Glycol Furanoate): A Member of the Furan-Based Polyester Family with Smart Barrier Performances for Sustainable Food Packaging Applications.

PubMed

Genovese, Laura; Lotti, Nadia; Siracusa, Valentina; Munari, Andrea

2017-09-04

In the last decade, there has been an increased interest from the food packaging industry toward the development and application of bioplastics, to contribute to the sustainable economy and to reduce the huge environmental problem afflicting the planet. In the present work, we focus on a new furan-based polyester, poly(neopentyl glycol 2,5-furanoate) (PNF) to be used for sustainable food packaging applications. The aromatic polyester was successfully synthesized with high molecular weight, through a solvent-free process, starting directly from 2,5-furandicarboxylic acid. PNF was revealed to be a material with good thermal stability, characterized by a higher T g and T m and a lower RAF fraction compared to poly(propylene 2,5-furanoate) (PPF), ascribable to the two methyl side groups present in PNF glycol-sub-unit. PNF's mechanical characteristics, i.e., very high elastic modulus and brittle fracture, were found to be similar to those of PPF and PEF. Barrier properties to different gases, temperatures and relative humidity were evaluated. From the results obtained, PNF was showed to be a material with very smart barrier performances, significantly superior with respect to PEF's ones. Lastly, PNF's permeability behavior did not appreciably change after contact with food simulants, whereas it got worse with increasing RH, due to the polar nature of furan ring.

Recycling steel-manufacturing slag and harbor sediment into construction materials.

PubMed

Wei, Yu-Ling; Lin, Chang-Yuan; Cheng, Shao-Hsiang; Wang, H Paul

2014-01-30

Mixtures consisting of harbor sediment and slag waste from steel industry containing toxic components are fired to produce non-hazardous construction materials. The fired pellets become lighter as firing temperature increases. At a sintering temperature of ≦1050°C, the fired pellets are in a form of brick-like product, while at 1100°C, they become lightweight aggregates. Calcium silicate, kyanite, and cristobalite are newly formed in the pellets after firing, demonstrating that calcium oxide acts as a flux component and chemically reacted with Si- and/or Al-containing components to promote sintering. Dioxin/furan content present in the pure slag is 0.003ng I-TEQg(-1) and, for the fired pellet consisting of slag and sediment, the content appears to be destructed and diminishes to 0.0003ng I-TEQg(-1) after 950°C-firing; while it is 0.002ng I-TEQg(-1) after firing at 1100°C, suggesting that dioxins/furans in the 950°C-fired pellets have a greater chance to escape to atmosphere due to a slower sintering reaction and/or that construction of dioxins/furans from molten chloride salts co-exists with their destruction. Multiple toxicity characteristic leaching procedure extracts Cu, Cr, Zn, Se, Cd, Pb, Ba, As, and Hg from all fired products at negligible levels. Copyright © 2013 Elsevier B.V. All rights reserved.

Optimizing removal of arsenic, chromium, copper, pentachlorophenol and polychlorodibenzo-dioxins/furans from the 1-4 mm fraction of polluted soil using an attrition process.

PubMed

Guemiza, Karima; Coudert, Lucie; Tran, Lan Huong; Metahni, Sabrine; Blais, Jean-François; Besner, Simon; Mercier, Guy

2017-08-01

The objective of this study was to evaluate, at a pilot scale, the performance of an attrition process for removing As, Cr, Cu, pentachlorophenol (PCP) and polychlorodibenzodioxins and furans (PCDDF) from a 1-4 mm soil fraction. A Box-Behnken experimental design was utilized to evaluate the influence of several parameters (temperature, surfactant concentration and pulp density) and to optimize the main operating parameters of this attrition process. According to the results, the concentration of surfactant (cocamidopropylbetaine-BW) was the main parameter influencing both PCP and PCDDF removal from the 1-4 mm soil fraction by attrition. The behavior of each 2,3,7,8-PCDD/F congener during the attrition process was studied. The results indicated that the concentration of surfactant had a significant and positive effect on the removal of almost all of the dioxin and furan. The removal of 56%, 55%, 50%, 67% and 62% of the contaminants were obtained for As, Cr, Cu, PCP and PCDDF, respectively, using the optimized conditions ([BW]= 2% (w.w-1), T = 25°C and PD = 40% (w.w-1)). These results showed that attrition in the presence of a surfactant can be efficiently used to remediate the coarse fractions of soil contaminated by As, Cr, Cu, PCP and PCDDF.

Deactivation via ring opening: A quantum chemical study of the excited states of furan and comparison to thiophene

NASA Astrophysics Data System (ADS)

Gavrilov, Nemanja; Salzmann, Susanne; Marian, Christel M.

2008-06-01

Minimum nuclear arrangements of the ground and low-lying excited electronic states of furan were obtained by means of (time dependent) Kohn-Sham density functional theory. A combined density functional/multi-reference configuration interaction method (DFT/MRCI) was employed to compute the spectral properties at these points. Multiple minima were found on the first excited singlet (S 1) potential energy hypersurface with electronic structures S1, S2, S3 corresponding to the 1 1A 2 (π → 3s-Ryd), 1 1B 2 (π → π ∗), and 2 1A 1 (π → π ∗) states in the vertical absorption spectrum, respectively. In analogy to recently published studies in thiophene [S. Salzmann, M. Kleinschmidt, J. Tatchen, R. Weinkauf, C.M. Marian, Phys. Chem. Chem. Phys. 10 (2008) 380] a deactivation mechanism for electronically excited furan was detected that involves the opening of the pentacyclic ring. We found a nearly barrierless relaxation pathway from the Franck-Condon region along a C-O bond-breaking coordinate. Hereby the initially excited 1B 2 (π → π ∗) state undergoes a conical intersection with a 1B 1 (π → σ ∗) state. The system can return to the electronic ground state through a second conical intersection of the 1(π → σ ∗) state before the minimum of that B 1 state is reached.

Volatile Compounds Produced by Lactobacillus paracasei During Oat Fermentation.

PubMed

Lee, Sang Mi; Oh, Jieun; Hurh, Byung-Serk; Jeong, Gwi-Hwa; Shin, Young-Keum; Kim, Young-Suk

2016-12-01

This study investigated the profiles of volatile compounds produced by Lactobacillus paracasei during oat fermentation using gas chromatography-mass spectrometry coupled with headspace solid-phase microextraction method. A total of 60 compounds, including acids, alcohols, aldehydes, esters, furan derivatives, hydrocarbons, ketones, sulfur-containing compounds, terpenes, and other compounds, were identified in fermented oat. Lipid oxidation products such as 2-pentylfuran, 1-octen-3-ol, hexanal, and nonanal were found to be the main contributors to oat samples fermented by L. paracasei with the level of 2-pentylfuran being the highest. In addition, the contents of ketones, alcohols, acids, and furan derivatives in the oat samples consistently increased with the fermentation time. On the other hand, the contents of degradation products of amino acids, such as 3-methylbutanal, benzaldehyde, acetophenone, dimethyl sulfide, and dimethyl disulfide, decreased in oat samples during fermentation. Principal component analysis (PCA) was applied to discriminate the fermented oat samples according to different fermentation times. The fermented oats were clearly differentiated on PCA plots. The initial fermentation stage was mainly affected by aldehydes, whereas the later samples of fermented oats were strongly associated with acids, alcohols, furan derivatives, and ketones. The application of PCA to data of the volatile profiles revealed that the oat samples fermented by L. paracasei could be distinguished according to fermentation time. © 2016 Institute of Food Technologists®.

Cross sections for electron scattering from furan molecules: Measurements and calculations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Szmytkowski, Czeslaw; Mozejko, Pawel; Ptasinska-Denga, Elzbieta

Electron-scattering cross sections have been determined for the furan (C{sub 4}H{sub 4}O) molecule, both experimentally and theoretically. An absolute total cross section (TCS) has been measured over energies from 0.6 to 400 eV using a linear electron-transmission method. The TCS energy function is dominated with a very broad enhancement, between 1.2 and 9 eV; on the low-energy side, some resonant structures are visible. Integral elastic (ECS) and ionization (ICS) cross sections have been also calculated up to 4 keV in the additivity rule approximation and the binary-encounter-Bethe approach, respectively. Their sum, ECS+ICS, is in a very good agreement with themore » measured TCS above 70 eV.« less

2H-pyran-2-one and 2H-furan-2-one derivatives from the plant endophytic fungus Pestalotiopsis fici.

PubMed

Liu, Shuchun; Liu, Xiangyu; Guo, Liangdong; Che, Yongsheng; Liu, Ling

2013-11-01

Two new α-pyrones (=2H-pyran-2-ones), ficipyrones A and B (1 and 2, resp.), and two new α-furanones (=2H-furan-2-ones), ficifuranones A and B (3 and 4, resp.), together with three known metabolites, antibiotic F 0368 (5), hydroxyseiridin (6), and hydroxyisoseiridin (7), were isolated from solid cultures of the plant endophytic fungus Pestalotiopsis fici. Their structures were elucidated primarily by NMR spectroscopy, and the absolute configuration of 1 was deduced from the circular-dichroism (CD) data. Compound 1 showed antifungal activity against the plant pathogen Gibberella zeae (CGMCC 3.2873) with an IC50 value of 15.9 μM. Copyright © 2013 Verlag Helvetica Chimica Acta AG, Zürich.

From indole to pyrrole, furan, thiophene and pyridine: Search for novel small molecule inhibitors of bacterial transcription initiation complex formation.

PubMed

Thach, Oscar; Mielczarek, Marcin; Ma, Cong; Kutty, Samuel K; Yang, Xiao; Black, David StC; Griffith, Renate; Lewis, Peter J; Kumar, Naresh

2016-03-15

The search for small molecules capable of inhibiting transcription initiation in bacteria has resulted in the synthesis of N,N'-disubstituted hydrazines and imine-carbohydrazides comprised of indole, pyridine, pyrrole, furan and thiophene using the respective trichloroacetyl derivatives, carbohydrazides and aldehydes. Replacement of the indole moiety by smaller heterocycles linked by CONHNC linkers afforded a broad variety of compounds efficiently targeting the RNA polymerase-σ(70)/σ(A) interaction as determined by ELISA and exhibiting increased inhibition of the growth of Escherichia coli compared to Bacillus subtilis in culture. The structural features of the synthesized transcription initiation inhibitors needed for antibacterial activity were identified employing molecular modelling and structure-activity relationship (SAR) studies. Copyright © 2016 Elsevier Ltd. All rights reserved.

Synthetic Studies Towards the Core Structure of Nakadomarin A by a Thioamide-Based Strategy

PubMed Central

Chavda, Jai K; Procopiou, Panayiotis A; Horton, Peter N; Coles, Simon J; Porter, Michael J

2014-01-01

The tricyclic BCD substructure of the marine natural product nakadomarin A has been synthesised. The strategy utilised a key carbon–carbon bond-forming reaction between a furan and an N-acyliminium ion derived from a secondary thiolactam. In addition, a novel three-component coupling reaction between a thioamide, an allylic bromide and an isocyanate, leading to the establishment of two new stereogenic centres, is reported. Two key steps in a projected total synthesis of nakadomarin A have been realised by using the unique chemistry of thioamides. Formation of the carbocyclic B ring can be effected by nucleophilic attack of a furan on a thiolactam-derived iminium ion, and the key quaternary centre can be established by a novel three-component coupling reaction. PMID:24829538

Simultaneous grouping and ranking with combination of SOM and TOPSIS for selection of preferable analytical procedure for furan determination in food.

PubMed

Jędrkiewicz, Renata; Tsakovski, Stefan; Lavenu, Aurore; Namieśnik, Jacek; Tobiszewski, Marek

2018-02-01

Novel methodology for grouping and ranking with application of self-organizing maps and multicriteria decision analysis is presented. The dataset consists of 22 objects that are analytical procedures applied to furan determination in food samples. They are described by 10 variables, referred to their analytical performance, environmental and economic aspects. Multivariate statistics analysis allows to limit the amount of input data for ranking analysis. Assessment results show that the most beneficial procedures are based on microextraction techniques with GC-MS final determination. It is presented how the information obtained from both tools complement each other. The applicability of combination of grouping and ranking is also discussed. Copyright © 2017 Elsevier B.V. All rights reserved.

Electronic Excitation of Furan by Low Energy Electrons

NASA Astrophysics Data System (ADS)

Hargreaves, Leigh R.; Khakoo, Murtadha A.; Lopes, Maria Cristina A.; da Costa, Romarly; Bettega, Marcio H. F.; Lima, Marco A. P.

2011-10-01

We present absolute differential cross section (DCS) measurements and calculations of electron impact excitation of the lowest lying triplet 3B2 and 3A1 electronic states of furan. The incident electron energy range of the present study was 5-15eV. The experimental data were normalized to the elastic DCS data of. The cross sections were determined by unfolding electron energy loss spectra, using an open source data analysis package and the spectroscopic assignments of. The calculations employ a Multichannel Schwinger method with a 9-state closed coupling CI configuration including polarized pseudo-potentials. The preliminary theoretical results show reasonable agreement with experiment below 10eV, but differ at higher energies. Funded by the US NSF and the Brazilian funding agencies CNPq, CAPES and FAPESP.

Biomass pre-treatment for co-production of high-concentration C5- and C6-carbohydrates and their derivatives

DOEpatents

Dumesic, James A.; Martin Alonso, David; Luterbacher, Jeremy Scott

2016-06-07

Described is a method of processing biomass to separate it into a liquid fraction enriched in solubilized C5-sugar-containing oligomers and C-5 sugar monomers and a solid fraction enriched in substantially insoluble cellulose and C6-sugar-containing oligomers. The method includes the steps of reacting biomass with a solvent system comprising water, at least one lactone, or at least one furan, or at least one cyclic ether, and at least one acid, for a time and at a temperature to yield the liquid and solid fractions. The liquid and solid fractions may then be separated. Gamma-valeroloactone is a preferred lactone for use in the solvent system. Tetrahydrofuran is a preferred furan species for use in the solvent system.

Theoretical investigation of the dipole polarisability and second hyperpolarisability of cyclopentadiene homologues C 4H 4XH 2 (X=C, Si, Ge, Sn)

NASA Astrophysics Data System (ADS)

Alparone, A.; Millefiori, A.; Millefiori, S.

2004-03-01

Static and frequency-dependent electronic dipole polarisability, α, and second hyperpolarisability, γ, of the cyclopentadiene homologues C 4H 4XH 2 (X=C, Si, Ge, Sn) were calculated by ab initio HF, MP2 and DFT-B3LYP methods using Sadlej POL basis sets, including vibrational and relativistic effects. The latter calculations were extended also to the furan homologues for comparison. The results show that both α and γ values increase monotonically as the heteroatom size increases. The energy values of the electronic transitions to the two lowest singlet 1 1B2 and 2 1A1 excited states decrease not uniformly as the heteroatom becomes heavier and the two-state model approximation is not adequate to explain the evolution of the (hyper)polarisability along the series, which indeed is essentially determined by the heteroatom property. Frequency dispersion correction on α increases down the group, by contrast γ dispersion is highest in cyclopentadiene and almost constant, at a lower value, in the heavier homologues. Electron correlation correction on the calculated properties is positive and rather large on γ. HF relativistic effects on < α> and < γ> are of little importance for both stannole and tellurophene and cannot account for the observed large discrepancy between the experimental and theoretical < γe>(- ω; ω, ω,- ω) value in the latter compound. Vibrational contributions are calculated for the optically-heterodyned optical Kerr process (OHD-OKE). They are non negligible and show a clear heavy atom dependence. In the cyclopentadiene series they amount to 4-10% of < αe> and to 8-16% of < γe>(- ω; ω, ω,- ω), while they are somewhat lower in the furan series. The transversal γxxxx value is higher in the cyclopentadiene than in the furan series by ca. 30-40%, suggesting that α- α'-linked cyclopentadiene homologues can be considered as valid alternatives to the corresponding furan homologues in projecting π-conjugated oligomers and polymers for NLO applications.

Limited mobility of dioxins near San Jacinto super fund site (waste pit) in the Houston Ship Channel, Texas due to strong sediment sorption.

PubMed

Louchouarn, Patrick; Seward, Shaya M; Cornelissen, Gerard; Arp, Hans Peter H; Yeager, Kevin M; Brinkmeyer, Robin; Santschi, Peter H

2018-07-01

Sediments from a waste pit in Houston Ship Channel (HSC) were characterized using a number of molecular markers of natural organic matter fractions (e.g., pyrogenic carbon residues, PAHs, lignins), in addition to dioxins, in order to test the hypothesis that the dispersal and mobility of dioxins from the waste pit in the San Jacinto River is minimal. Station SG-6, sampled at the site of the submerged waste pit, had the highest dioxin/furan concentrations reported for the Houston Ship Channel/Galveston Bay (HSC/GB) system (10,000-46,000 pg/g), which translated into some of the highest reported World Health Organization Toxic Equivalents (TEQs: 2000-11,000 pg/g) in HSC sediments. Using a multi-tracer approach, this study confirmed our hypothesis that sludges from chlorinated pulps are a very likely source of dioxins/furans to this pit. However, this material also contained large quantities of additional hydrophobic organic contaminants (PAHs) and pyrogenic markers (soot-BC, levoglucosan), pointing to the co-occurrence of petroleum hydrocarbons and combustion byproducts. Comparison of dioxin/furan signatures in the waste pit with those from sediments of the HSC and a control site suggests that the remobilization of contaminated particles did not occur beyond the close vicinity of the pit itself. The dioxins/furans in sediments outside the waste pit within the HSC are rather from other diffuse inputs, entering the sedimentary environment through the air and water, and which are comprised of a mixture of industrial and municipal sources. Fingerprinting of waste pit dioxins indicates that their composition is typical of pulp and paper sources. Measured pore water concentrations were 1 order of magnitude lower than estimated values, calculated from a multiphase sorption model, indicating low mobility of dioxins within the waste pit. This is likely accomplished by co-occurring and strong sorbing pyrogenic and petrogenic residues in the waste pit, which tend to keep dioxins strongly sorbed to particles. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

77 FR 3389 - Approval and Promulgation of State Air Quality Plans for Designated Facilities and Pollutants...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-01-24

... regulates a mixture of air pollutants including organics (dioxins/furans), carbon monoxide, metals (cadmium... procedure, Air pollution control, Aluminum, Fertilizers, Fluoride, Intergovernmental relations, Paper and...

Summary of information on aquatic biota and their habitats in the Willamette Basin, Oregon, through 1995

USGS Publications Warehouse

Altman, Bob; Henson, C.M.; Waite, I.R.

1997-01-01

Aquatic toxicological investigations in the basin have focused primarily on fish. These studies have addressed chlorinated pesticides, polychlorinated biphenyls (PCBs), dioxins and furans, polycyclic aromatic hydrocarbons (PAHs), and trace elements in aquatic tissue, as well as fish health assessments, skeletal abnormalities, and aquatic toxicological responses. Several pesticides exceeded U.S. Environmental Protection Agency and State water-quality criteria for the protection of aquatic life. Elevated PCB, dioxin, and furan concentrations were associated with point sources, such as pulp and paper mills. Elevated concentrations of mercury in aquatic tissue were associated with several reservoirs. Fish health assessments and skeletal abnormality studies detected high levels of abnormalities in fish from the main stem Willamette River. Few investigations have examined aquatic toxicological responses, such as enzyme induction assays, growth assays, and biomarker studies.

Activation of cryptic metabolite production through gene disruption: Dimethyl furan-2,4-dicarboxylate produced by Streptomyces sahachiroi.

PubMed

Simkhada, Dinesh; Zhang, Huitu; Mori, Shogo; Williams, Howard; Watanabe, Coran M H

2013-01-01

At least 65% of all small molecule drugs on the market today are natural products, however, re-isolation of previously identified and characterized compounds has become a serious impediment to the discovery of new bioactive natural products. Here, genetic knockout of an unusual non-ribosomal peptide synthetase (NRPS) C-PCP-C module, aziA2, is performed resulting in the accumulation of the secondary metabolite, dimethyl furan-2,4-dicarboxylate. The cryptic metabolite represents the first non-azinomycin related compound to be isolated and characterized from the soil bacterium, S. sahachiroi. The results from this study suggest that abolishing production of otherwise predominant natural products through genetic knockout may constitute a means to "activate" the production of novel secondary metabolites that would otherwise lay dormant within microbial genome sequences.

Palladium-Copper Catalyzed Alkyne Activation as an Entry to Multicomponent Syntheses of Heterocycles

NASA Astrophysics Data System (ADS)

Müller, Thomas J. J.

Alkynones and chalcones are of paramount importance in heterocyclic chemistry as three-carbon building blocks. In a very efficient manner, they can be easily generated by palladium-copper catalyzed reactions: ynones are formed from acid chlorides and terminal alkynes, and chalcones are synthesized in the sense of a coupling-isomerization (CI) sequence from (hetero)aryl halides and propargyl alcohols. Mild reaction conditions now open entries to sequential and consecutive transformations to heterocycles, such as furans, 3-halo furans, pyrroles, pyrazoles, substituted and annelated pyridines, annelated thiopyranones, pyridimines, meridianins, benzoheteroazepines and tetrahydro-β-carbolines, by consecutive coupling-cyclocondensation or CI-cyclocondensation sequences, as new diversity oriented routes to heterocycles. Domino reactions based upon the coupling-isomerization reaction (CIR) have been probed in the synthesis of antiparasital 2-substituted quinoline derivatives and highly luminescent spiro-benzofuranones and spiro-indolones.

Method of making thermally removable polyurethanes

DOEpatents

Loy, Douglas A.; Wheeler, David R.; McElhanon, James R.; Saunders, Randall S.; Durbin-Voss, Marvie Lou

2002-01-01

A method of making a thermally-removable polyurethane material by heating a mixture of a maleimide compound and a furan compound, and introducing alcohol and isocyanate functional groups, where the alcohol group and the isocyanate group reacts to form the urethane linkages and the furan compound and the maleimide compound react to form the thermally weak Diels-Alder adducts that are incorporated into the backbone of the urethane linkages during the formation of the polyurethane material at temperatures from above room temperature to less than approximately 90.degree. C. The polyurethane material can be easily removed within approximately an hour by heating to temperatures greater than approximately 90.degree. C. in a polar solvent. The polyurethane material can be used in protecting electronic components that may require subsequent removal of the solid material for component repair, modification or quality control.

2-(Hetero(aryl)methylene)hydrazine-1-carbothioamides as potent urease inhibitors.

PubMed

Saeed, Aamer; Imran, Aqeel; Channar, Pervaiz A; Shahid, Mohammad; Mahmood, Wajahat; Iqbal, Jamshed

2015-02-01

A small series of 2-(hetero(aryl)methylene) hydrazine-1-carbothioamides including two aryl derivatives was synthesized and tested for their inhibitory activity against urease. Compound (E)-2-(Furan-2-ylmethylene) hydrazine-1-carbothioamide (3f), having a furan ring, was the most potent inhibitor of urease with an IC50 value of 0.58 μM. Molecular modeling was carried out through docking the designed compounds into the urease binding site to predict whether these derivatives have analogous binding mode to the urease inhibitors. The study revealed that all of the tested compounds bind with both metal atoms at the active site of the enzyme. The aromatic ring of the compounds forms ionic interactions with the residues, Ala(440), Asp(494), Ala(636), and Met(637). © 2014 John Wiley & Sons A/S.

The concentration and distribution of 2,3,7,8-dibenzo-p-dioxins/-furans in chickens

NASA Technical Reports Server (NTRS)

Ferrario, J.; Byrne, C.

2000-01-01

The concentrations of the 2,3,7,8-Cl substituted dibenzo-p-dioxins/-furans (PCDDs/PCDFs) were determined in the edible tissues of whole chicken fryers and compared with the values found in their abdominal fat. The values are presented both on a whole weight basis and on a lipid adjusted basis for each tissue. While there is a marked difference in the concentration of the 2,3,7,8-dibenzo-p-dioxins in the edible tissues expressed on a whole weight basis, the lipid-adjusted concentrations of the individual dioxins were not statistically different in the various tissues. This validates the use of lipid adjusted concentrations of 2,3,7,8-PCDDs/PCDFs in abdominal fat for the determination of the presence of these compounds in different tissues.

Rational Topological Design for Fluorescence Enhancement upon Aggregation of Distyrylfuran Derivatives.

PubMed

Mallet, Charlotte; Moussallem, Chady; Faurie, Alexandre; Allain, Magali; Gohier, Frédéric; Skene, William G; Frère, Pierre

2015-05-18

A series of 2,5-distyrylfuran derivatives bearing pentafluorophenyl- and cyanovinyl units have been synthesized for aggregation-induced emission (AIE). The effect of the type and extent of the supramolecular connections on the AIE of the furan derivatives were examined and correlated with their X-ray crystal structures. It was found that the simultaneous presence of cyano and perfluorophenyl units strongly enhances the fluorescence upon aggregation. Single-crystal X-ray diffraction analysis confirmed that CH⋅⋅⋅F, F⋅⋅⋅F, CH⋅⋅⋅nitrile, Ar⋅⋅⋅ArF (Ar=aryl, ArF =fluoroaryl), and nitrile⋅⋅⋅ArF intra- and intermolecular interactions drive the topology of the molecule and that solid-state supramolecular contacts favor AIE of the furan derivatives. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

D-Galacturonic acid as a highly reactive compound in nonenzymatic browning. 1. Formation of browning active degradation products.

PubMed

Bornik, Maria-Anna; Kroh, Lothar W

2013-04-10

Thermal treatment of an aqueous solution of D-galacturonic acid at pH 3, 5, and 8 led to rapid browning of the solution and to the formation of carbocyclic compounds such as reductic acid (2,3-dihydroxy-2-cyclopenten-1-one), DHCP (4,5-dihydroxy-2-cyclopenten-1-one), and furan-2-carbaldehyde, as degradation products in weak acidic solution. Studies on their formation revealed 2-ketoglutaraldehyde as their common key intermediate. Norfuraneol (4-hydroxy-5-methyl-3-(2H)-furanone) is a typical alkaline degradation product and formed after isomerization. Further model studies revealed reductic acid as an important and more browning active compound than furan-2-carbaldehyde, which led to a red color of the model solution. This red-brown color is also characteristic of thermally treated uronic acid solutions.

The PCDD/PCDF Dioxin releases in the climate of environment of Jordan in the period (2000-2008)

NASA Astrophysics Data System (ADS)

Al-Dabbas, Mohammed Awwad

2010-04-01

Many environment problems of the full using of several categories of processing include mining, heat generators, direct combustion of forest fires, cement production, power plant, transport, medical waste. Dioxin/furan releases from these categories are one of these environment problems. Possible lines of reducing the PCDD/PCDF (Polychlorinated dibenzo-para-dioxins/Polychlorinated dibenzofurans) releases from these categories are elucidated. The contribution of this paper is present the identification and estimation of the latest figure of dioxin/furan releases in the climate of environment of Jordan in the period 2000-2008 from the following categories (cement, aluminum, ceramic, medical waste, power plant, land fill, ferrous and non-ferrous metals, uncontrolled combustion process (biomass burning, waste burning, accidental fires in house, transport). These finding shows the sign of growth of estimated PCDD/PCDF releases from categories which did not calculated and followed after 2003. The result shows the highest PCDD/PCDF release from landfill fires (62.75 g TEQ/year), medical waste (8.8264 g TEQ/year), and transport (3.0145 g TEQ/year). Jordan seeks by next years, a reduction in total releases of dioxins and furans from sources resulting from human activity. This challenge will apply to the aggregate of releases to the air nationwide and of releases to the water within the Jordan area. Jordan should conduct air monitoring for dioxin in order to track fluctuations in atmospheric deposition levels.

Influence of electron delocalization in heterocyclic core systems on the electrochemical communication in 2,5-di- and 2,3,4,5-tetraferrocenyl thiophenes, furans, and pyrroles.

PubMed

Hildebrandt, Alexander; Schaarschmidt, Dieter; Claus, Ron; Lang, Heinrich

2011-11-07

A series of 2,5-di- and 2,3,4,5-tetraferrocenyl-substituted thiophenes, furans, and pyrroles were synthesized using the Negishi C,C cross-coupling protocol. The electronic and electrochemical properties of these compounds were investigated by cyclic voltammetry (CV), square wave voltammetry (SWV), and in situ UV-vis/NIR spectroscopy. The molecular structures of 2,5-diferrocenyl furan and 2,3,4,5-tetraferrocenyl-1-methyl-1H-pyrrole in the solid state are discussed. The ferrocenyls could sequentially be oxidized giving two or four reversible responses for the appropriate di- or tetraferrocenyl-substituted heterocyclic molecules. The observed ΔE°' values range between 186 and 450 mV. The NIR measurements confirm electronic communication as intervalence charge transfer (IVCT) absorptions were found in the corresponding mono- and in case of the tetraferrocenyl compounds also in the dicationic species. All compounds, except tetraferrocenyl thiophene (a class I system), were classified as class II systems according to Robin and Day. They show a linear relationship between ΔE°' and the IVCT oscillator strength f which could be shown for the first time in organometallic chemistry. This was possible because the series of molecules exhibit analogous geometries and hence, similar electrostatic properties. This correlation was confirmed by electro- and spectro-electrochemical measurements. Within these studies a new approach for the estimation of the effective electron transfer distances r(ab) is discussed. © 2011 American Chemical Society

A DFT study of volatile organic compounds adsorption on transition metal deposited graphene

NASA Astrophysics Data System (ADS)

Kunaseth, Manaschai; Poldorn, Preeyaporn; Junkeaw, Anchalee; Meeprasert, Jittima; Rungnim, Chompoonut; Namuangruk, Supawadee; Kungwan, Nawee; Inntam, Chan; Jungsuttiwong, Siriporn

2017-02-01

Recently, elevated global emission of volatile organic compounds (VOCs) was associated to the acceleration and increasing severity of climate change worldwide. In this work, we investigated the performance of VOCs removal via modified carbon-based adsorbent using density functional theory. Here, four transition metals (TMs) including Pd, Pt, Ag, and Au were deposited onto single-vacancy defective graphene (SDG) surface to increase the adsorption efficiency. Five prototypical VOCs including benzene, furan, pyrrole, pyridine, and thiophene were used to study the adsorption capability of metal-deposited graphene adsorbent. Calculation results revealed that Pd, Pt, Au, and Ag atoms and nanoclusters bind strongly onto the SDG surface. In this study, benzene, furan and pyrrole bind in the π-interaction mode using delocalized π-electron in aromatic ring, while pyridine and thiophene favor X- interaction mode, donating lone pair electron from heteroatom. In terms of adsorption, pyridine VOC adsorption strengths to the TM-cluster doped SDG surfaces are Pt4 (-2.11 eV) > Pd4 (-2.05 eV) > Ag4 (-1.53 eV) > Au4 (-1.87 eV). Our findings indicate that TM-doped SDG is a suitable adsorbent material for VOC removal. In addition, partial density of states analysis suggests that benzene, furan, and pyrrole interactions with TM cluster are based on p-orbitals of carbon atoms, while pyridine and thiophene interactions are facilitated by hybridized sp2-orbitals of heteroatoms. This work provides a key insight into the fundamentals of VOCs adsorption on carbon-based adsorbent.

Determination of 2,3,7,8-chlorine-substituted dibenzo-p-dioxins and -furans at the part per trillion level in United States beef fat using high-resolution gas chromatography/high-resolution mass spectrometry

NASA Technical Reports Server (NTRS)

Ferrario, J.; Byrne, C.; McDaniel, D.; Dupuy, A. Jr; Harless, R.

1996-01-01

As part of the U.S. EPA Dioxin Reassessment Program, the 2,3,7,8-chlorine-substituted dibenzo-p-dioxins and furans were measured at part per trillion (ppt) levels in beef fat collected from slaughter facilities in the United States. This is the first statistically designed national survey of these compounds in the U.S. beef supply. Analyte concentrations were determined by high-resolution gas chromatography/high-resolution mass spectrometry, using isotope dilution methodology. Method limits of detection on a whole weight basis were 0.05 ppt for TCDD and 0.10 ppt for TCDF, 0.50 ppt for the pentas (PeCDDs/PeCDFs)/hexas (HxCDDs/HxCDFs)/heptas (HpCDDs/HpCDFs), and 3.00 ppt for the octas (OCDD/OCDF). Method detection and quantitation limits were established on the basis of demonstrated performance criteria utilizing fortified samples rather than by conventional signal-to-noise or variability of response methods. The background subtraction procedures developed for this study minimized the likelihood of false positives and increased the confidence associated with reported values near the detection limits. Mean and median values for each of the 2,3,7,8-Cl-substituted dioxins and furans are reported, along with the supporting information required for their interpretation. The mean toxic equivalence values for the samples are 0.35 ppt (nondetects = 0) and 0.89 ppt (nondetects = 1/2 LOD).

Trace contaminant concentrations in the Kara Sea and its adjacent rivers, Russia.

PubMed

Sericano, J L; Brooks, J M; Champ, M A; Kennicutt, M C; Makeyev, V V

2001-11-01

Trace organic (chlorinated pesticides, PCBs, PAHs and dioxins/furans) and trace metal concentrations were measured in surficial sediment and biological tissues (i.e., worms, crustaceans, bivalve molluscs, and fish livers) collected from the Russian Arctic. Total DDT, chlordane, PCB and PAH concentrations ranged from ND to 1.2, ND to <0.1, ND to 1.5 and <20-810 ng g(-1), respectively, in a suite of 40 surficial sediment samples from the Kara Sea and the adjacent Ob and Yenisey Rivers. High sedimentary concentrations of contaminants were found in the lower part of the Yenisey River below the salt wedge. Total dioxins/furans were analysed in a subset of 20 sediment samples and ranged from 1.4 to 410 pg g(-1). The highest trace organic contaminant concentrations were found in organisms, particularly fish livers. Concentrations as high as 89 ng g(-1) chlordane; 1010 ng g(-1) total DDTs; 460 ng g(-1) total PCBs; and 1110 ng g(-1) total PAH, were detected. A subset of 11 tissue samples was analysed for dioxins and furans with total concentrations ranging from 12 to 61 pg g(-1). Concentrations of many trace organic and metal contaminants in the Kara Sea appear to originate from riverine sources and atmospheric transport from more temperate areas. Most organic contaminant concentrations in sediments were low; however, contaminants are being concentrated in organisms and may pose a health hazard for inhabitants of coastal villages.

Interplay of metals and bromine with dioxin-related compounds concentrated in e-waste open burning soil from Agbogbloshie in Accra, Ghana.

PubMed

Fujimori, Takashi; Itai, Takaaki; Goto, Akitoshi; Asante, Kwadwo A; Otsuka, Masanari; Takahashi, Shin; Tanabe, Shinsuke

2016-02-01

Open burning of electronic waste (e-waste) releases various metals and organohalogen compounds in the environment. Here we investigated the interplay of metals (Cu, Pb, Zn, Fe, Co, and Sr) and bromine (Br) in the formation of dioxin-related compounds (DRCs), including polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (DL-PCBs), as well as non-regulated DRCs such as polybrominated dibenzo-p-dioxins/furans (PBDD/Fs) and their monobrominated PCDD/Fs in soils sampled from open burning e-waste sites at Agbogbloshie in Accra, Ghana. The predominant DRCs were PBDFs, PCDFs, PCDDs, and DL-PCBs. Statistical analyzes, X-ray absorption spectroscopy, and the PCDF/PCDD ratio suggested possible formation paths of PCDD/Fs and DL-PCBs by catalytic behaviors of copper chlorides (CuCl, CuCl2, and Cu2(OH)3Cl) and thermal breakdown of polyvinyl chloride. Predominant formation of brominated furans may be derived from electron transfer from intermediates of PBDE to copper, Cu(II) → Cu(I). Lead chloride also contributed to generate DRCs and may become highly bioaccessible through the open burning of e-waste. The main zinc species (ZnCl2 and ZnS) suggested a possible relationship to generate DRCs and specific zinc source such as tire burning. Cu, Pb, Zn, and Br contained in various e-wastes, wires/cables, plastics, and tires strongly influenced generation of many DRCs. Copyright © 2015 Elsevier Ltd. All rights reserved.

A novel difunctional acylhydrazone with isoxazole and furan heterocycles: Syntheses, structure, spectroscopic properties, antibacterial activities and theoretical studies of (E)-N‧-(furan-2-ylmethylene)-5-methylisoxazole-4-carbohydrazide

NASA Astrophysics Data System (ADS)

Jin, Yan-Xian; Zhong, Ai-Guo; Ge, Chang-Hua; Pan, Fu-You; Yang, Jian-Guo; Wu, Ying; Xie, Min; Feng, Hai-Wan

2012-02-01

In order to explore new functional materials, a novel acylhydrazone with isoxazole and furan heterocycles was synthesized and thoroughly investigated by X-ray crystallography, UV and fluorescence spectroscopy, cyclic voltammetry, thermoanalysis, density functional theory (DFT) and time-dependent density functional theory (TDDFT). The molecule has been demonstrated to crystallize in the monoclinic space group P21/c, with the unit cell parameters of (a = 11.3522(19) Å, b = 8.0700(14) Å, c = 12.872(2) Å; α = 90°, β = 106.969(12)°, γ = 90°). In addition, this compound shows characteristic UV absorption peaks at 205, 222 and 308 nm, and fluorescence emission peak at 486.1 nm, which according to our theoretic calculation can all be attributed to (p, π) → π∗ and π → π∗ intraligand charge-transfer transition (ILCT) respectively. According to our cyclic voltammetry result, an oxidation peak of the compound can be observed with onset oxidation potential (Eox) of 0.44 V. Furthermore, the results of antibacterial activities indicate the compound has broad-spectrum against Bacillus subtilis, Pseudomonas aeruginosa, Escherichia coli and Staphylococcus aureus, which can be supported by the molecular electrostatic potential (MEP). Therefore, this compound exhibits both antibacterial activity and photoluminescent property, namely difunctionality, suggesting that it has potential applications in many fields such as material science and photodynamic therapy.

Biologically active Schiff bases containing thiophene/furan ring and their copper(II) complexes: Synthesis, spectral, nonlinear optical and density functional studies

NASA Astrophysics Data System (ADS)

Gündüzalp, Ayla Balaban; Özsen, İffet; Alyar, Hamit; Alyar, Saliha; Özbek, Neslihan

2016-09-01

Schiff bases; 1,8-bis(thiophene-2-carboxaldimine)-p-menthane (L1) and 1,8-bis(furan-2-carboxaldimine)-p-menthane (L2) have been synthesized and characterized by elemental analysis, 1Hsbnd 13C NMR, UV-vis, FT-IR and LC-MS methods. 1H and 13C shielding tensors for L1 and L2 were calculated with GIAO/DFT/B3LYP/6-311++G(d,p) methods in CDCl3. The vibrational band assignments, nonlinear optical (NLO) activities, frontier molecular orbitals (FMOs) and absorption spectrum have been investigated by the same basis set. Schiff base-copper(II) complexes have been synthesized and structurally characterized with spectroscopic methods, magnetic and conductivity measurements. The spectroscopic data suggest that Schiff base ligands coordinate through azomethine-N and thiophene-S/furan-O donors (as SNNS and ONNO chelating systems) to give a tetragonal geometry around the copper(II) ions. Schiff bases and Cu(II) complexes have been screened for their biological activities on different species of pathogenic bacteria, those are, Gram positive bacteria: Bacillus subtitilus, Yersinia enterotica, Bacillus cereus, Listeria monocytogenes, Micrococcus luteus and Gram negative bacteria: Escherichia coli, Pseudomonas aeroginosa, Shigella dysenteriae, Salmonella typhi, Klebsiella pseudomonas by using microdilution technique (MIC values in mM). Biological activity results show that Cu(II) complexes have higher activities than parent ligands and metal chelation may affect significantly the antibacterial behavior of the organic ligands.

Difference analysis of the enzymatic hydrolysis performance of acid-catalyzed steam-exploded corn stover before and after washing with water.

PubMed

Zhu, Junjun; Shi, Linli; Zhang, Lingling; Xu, Yong; Yong, Qiang; Ouyang, Jia; Yu, Shiyuan

2016-10-01

The difference in the enzymatic hydrolysis yield of acid-catalyzed steam-exploded corn stover (ASC) before and after washing with water reached approximately 15 % under the same conditions. The reasons for the difference in the yield between ASC and washed ASC (wASC) were determined through the analysis of the composition of ASC prehydrolyzate and sugar concentration of enzymatic hydrolyzate. Salts produced by neutralization (CaSO4, Na2SO4, K2SO4, and (NH4)2SO4), sugars (polysaccharides, oligosaccharides, and monosaccharides), sugar-degradation products (weak acids and furans), and lignin-degradation products (ethyl acetate extracts and nine main lignin-degradation products) were back-added to wASC. Results showed that these products, except furans, exerted negative effect on enzymatic hydrolysis. According to the characteristics of acid-catalyzed steam explosion pretreatment, the five sugar-degradation products' mixture and salts [Na2SO4, (NH4)2SO4] showed minimal negative inhibition effect on enzymatic hydrolysis. By contrast, furans demonstrated a promotion effect. Moreover, soluble sugars, such as 13 g/L xylose (decreased by 6.38 %), 5 g/L cellobiose (5.36 %), 10 g/L glucose (3.67 %), as well as lignin-degradation products, and ethyl acetate extracts (4.87 %), exhibited evident inhibition effect on enzymatic hydrolysis. Therefore, removal of soluble sugars and lignin-degradation products could effectively promote the enzymatic hydrolysis performance.

Far-Infrared Synchrotron-Based Spectroscopy of Furan: Analysis of the ν14-ν11 Perturbation and the ν18 and ν19 Levels

NASA Astrophysics Data System (ADS)

Tokaryk, D. W.; Culligan, S. D.; Billinghurst, B. E.; van Wijngaarden, J. A.

2011-06-01

The ν14 vibrational level of furan lies 603 Cm-1 above the ground vibrational state. It is the lowest lying vibrational level for which a transition from the ground state is allowed. Other groups have conducted rotational analyses on fundamental bands of furan at 745 Cm-1 (ν13), 995 Cm-1 (ν7) and at 1067 Cm-1 (ν6). We have taken the rotationally resolved spectrum of the c-type ν14 band at the Canadian Light Source synchrotron with a Bruker IFS125HR Fourier transform spectrometer operating at 0.00096 Cm-1 resolution, and have found it to be perturbed by the ν11 band at 600 Cm-1, for which transitions from the ground vibrational state are forbidden. By taking the spectra of the b-type ν18 fundamental band and of the very weak c-type ν18- ν11 band we have been able to analyze the ν14- ν11 perturbation. We have also analyzed the spectrum of the b-type ν19 fundamental band. [2]{B. Pankoke, K. M. T. Yamada, G. Winnewisser, Z. Naturforsch. A 48 (1993) 1193-1202. [3]A. Mellouki, M. Herman, J. Demaison, B. Lemoine, L. Margulès, J. Mol. Spectrosc. 198 (1999) 348-357. [4]A. Mellouki, J. Vander Auwera, J. Demaison, M. Herman, J. Mol. Spectrosc. 209 (2001) 136-138.

40 CFR 62.15155 - What pollutants are regulated by this subpart?

Code of Federal Regulations, 2010 CFR

2010-07-01

... pollutants, in four groupings, are regulated: (a) Organics. Dioxins/furans. (b) Metals. (1) Cadmium. (2) Lead. (3) Mercury. (4) Opacity. (5) Particulate matter. (c) Acid gases. (1) Hydrogen chloride. (2) Nitrogen...

40 CFR 60.1705 - What emission limits must I meet? By when?

Code of Federal Regulations, 2010 CFR

2010-07-01

... modification after June 26, 1987, then you must comply with the dioxins/furans and mercury emission limits... construction or operating permit, if a permit modification is required. Final compliance with the dioxins...

EVALUATION OF DIOXIN EMISSIONS MONITORING SYSTEMS

EPA Science Inventory

Continuous samplers and real or semi-real-time continuous monitors for polychlorinated dibenzodioxins and furans provide significant advantages relative to conventional methods of extractive sampling. Continuous samplers collect long term samples over a time period of days to wee...

Crystal structures of hibiscus acid and hibiscus acid dimethyl ester isolated from Hibiscus sabdariffa (Malvaceae).

PubMed

Zheoat, Ahmed M; Gray, Alexander I; Igoli, John O; Kennedy, Alan R; Ferro, Valerie A

2017-09-01

The biologically active title compounds have been isolated from Hibiscus sabdariffa plants, hibiscus acid as a dimethyl sulfoxide monosolvate [systematic name: (2 S ,3 R )-3-hy-droxy-5-oxo-2,3,4,5-tetra-hydro-furan-2,3-di-carb-oxy-lic acid dimethyl sulfoxide monosolvate], C 6 H 6 O 7 ·C 2 H 6 OS, (I), and hibiscus acid dimethyl ester [systematic name: dimethyl (2 S ,3 R )-3-hy-droxy-5-oxo-2,3,4,5-tetra-hydro-furan-2,3-di-carboxyl-ate], C 8 H 10 O 7 , (II). Compound (I) forms a layered structure with alternating layers of lactone and solvent mol-ecules, that include a two-dimensional hydrogen-bonding construct. Compound (II) has two crystallographically independent and conformationally similar mol-ecules per asymmetric unit and forms a one-dimensional hydrogen-bonding construct. The known absolute configuration for both compounds has been confirmed.

Mitigation strategies of acrylamide, furans, heterocyclic amines and browning during the Maillard reaction in foods.

PubMed

Rannou, Cécile; Laroque, Delphine; Renault, Emilie; Prost, Carole; Sérot, Thierry

2016-12-01

The Maillard reaction (MR) occurs widely during food manufacture and storage, through controlled or uncontrolled pathways. Its consequences are ambiguous depending on the nature and processing of the food products. The MR is often used by food manufacturer to develop appealing aromas, colour or texture in food products (cereal based food, coffee, meat…). However, despite some positive aspects, the MR could decrease the nutritional value of food, generate potentially harmful compounds (e.g. acrylamide, furans, heterocyclic amines) or modify aroma or colour although it is not desired (milk, fruit juice). This paper presents a review of the different solutions available to control or moderate the MR in various food products from preventive to removal methods. A brief reminder of the role and influence of the MR on food quality and safety is also provided. Copyright © 2016 Elsevier Ltd. All rights reserved.

Acidic resin-catalysed conversion of fructose into furan derivatives in low boiling point solvents.

PubMed

Zhu, Hong; Cao, Quan; Li, Chunhu; Mu, Xindong

2011-09-27

Conversion of fructose into furan derivatives 5-hydroxymethylfurfural (HMF) and 5-methoxymethylfurfural (MMF) is performed in tetrahydrofuran (THF) and methanol-organic solvent systems, catalysed by an acidic resin Amberlyst-15. The melted fructose can be converted into HMF on the surface of the solid resin catalyst in the presence of THF as an extracting phase, which is a good solvent for HMF and other by-products. The solid resin catalyst can be reused eleven times without losing its catalytic ability, with an average HMF yield of approximately 50%. Upon the addition of methanol, the generated HMF can further react with methanol to form MMF, and the total yield of HMF and MMF could be promoted to 65%. GC-MS analysis confirms the formation of a small amount of methyl levulinate in methanolorganic solvent system. Copyright © 2011 Elsevier Ltd. All rights reserved.

A dihydro-β-agarofuran sesquiterpene from Maytenus boaria.

PubMed

Paz, Cristian; von Dossow, Daniela; Tiznado, Victor; Suarez, Sebastián; Cukiernik, Fabio D; Baggio, Ricardo

2017-06-01

The natural compound (1S,4S,5S,6R,7R,8R,9R,10S)-6-acetoxy-4,9,10-trihydroxy-2,2,5a,9-tetramethyloctahydro-2H-3,9a-methanobenzo[b]oxepin-5-yl furan-3-carboxylate, C 22 H 30 O 9 , (I), is a β-agarofuran sesquiterpene isolated from the seeds of Maytenus boaria as part of a study of the secondary metabolites from Chilean flora. The compound presents a central structure formed by a decalin system esterified with acetate at site 1 and furan-3-carboxylate at site 9. The chirality of the skeleton can be described as 1S,4S,5S,6R,7R,8R,9R,10S, which is consistent with that suggested by NMR studies. Unlike previously reported structures of sesquiterpenes containing a pure dihydro-β-agarofuran skeleton, (I) exhibits a three-dimensional hydrogen-bonded network.

The hydrodeoxygenation of bioderived furans into alkanes.

PubMed

Sutton, Andrew D; Waldie, Fraser D; Wu, Ruilian; Schlaf, Marcel; Silks, Louis A Pete; Gordon, John C

2013-05-01

The conversion of biomass into fuels and chemical feedstocks is one part of a drive to reduce the world's dependence on crude oil. For transportation fuels in particular, wholesale replacement of a fuel is logistically problematic, not least because of the infrastructure that is already in place. Here, we describe the catalytic defunctionalization of a series of biomass-derived molecules to provide linear alkanes suitable for use as transportation fuels. These biomass-derived molecules contain a variety of functional groups, including olefins, furan rings and carbonyl groups. We describe the removal of these in either a stepwise process or a one-pot process using common reagents and catalysts under mild reaction conditions to provide n-alkanes in good yields and with high selectivities. Our general synthetic approach is applicable to a range of precursors with different carbon content (chain length). This allows the selective generation of linear alkanes with carbon chain lengths between eight and sixteen carbons.

The hydrodeoxygenation of bioderived furans into alkanes

NASA Astrophysics Data System (ADS)

Sutton, Andrew D.; Waldie, Fraser D.; Wu, Ruilian; Schlaf, Marcel; ‘Pete' Silks, Louis A.; Gordon, John C.

2013-05-01

The conversion of biomass into fuels and chemical feedstocks is one part of a drive to reduce the world's dependence on crude oil. For transportation fuels in particular, wholesale replacement of a fuel is logistically problematic, not least because of the infrastructure that is already in place. Here, we describe the catalytic defunctionalization of a series of biomass-derived molecules to provide linear alkanes suitable for use as transportation fuels. These biomass-derived molecules contain a variety of functional groups, including olefins, furan rings and carbonyl groups. We describe the removal of these in either a stepwise process or a one-pot process using common reagents and catalysts under mild reaction conditions to provide n-alkanes in good yields and with high selectivities. Our general synthetic approach is applicable to a range of precursors with different carbon content (chain length). This allows the selective generation of linear alkanes with carbon chain lengths between eight and sixteen carbons.

Electron-ion dissociative recombination rate constants relevant to the Titan atmosphere and the Interstellar Medium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Osborne, David; Lawson, Patrick; Adams, Nigel, E-mail: ngadams@uga.edu

Following the arrival of Cassini at Titan in 2004, the Titan atmosphere has been shown to contain large complex polycyclic-aromatic hydrocarbons. Since Cassini has provided a great deal of data, there exists a need for kinetic rate data to help with modeling this atmosphere. One type of kinetic data needed is electron-ion dissociative recombination (e-IDR) rate constants. These data are not readily available for larger compounds, such as naphthalene, or oxygen containing compounds, such as 1,4 dioxane or furan. Here, the rate constants for naphthalene, 1,4 dioxane, and furan have been measured and their temperature dependencies are determined when possible,more » using the University of Georgia's Variable Temperature Flowing Afterglow. The rate constants are compared with those previously published for other compounds; these show trends which illustrate the effects which multi-rings and oxygen heteroatoms substitutions have upon e-IDR rate constants.« less

Reproduction of European eel jeopardised by high levels of dioxins and dioxin-like PCBs?

PubMed

Geeraerts, C; Focant, J-F; Eppe, G; De Pauw, E; Belpaire, C

2011-09-01

Dioxins, furans and dioxin-like polychlorinated biphenyls (PCBs) were analysed in muscle tissue from yellow phased European eel (Anguilla anguilla) from 38 sites in Belgium. Dioxin concentrations in eel vary considerably between sampling locations, indicating that yellow eel is a good indicator of local pollution levels. Measured levels of dioxin-like PCBs are much higher than those of the dioxins and furans. In the majority of the sites, eel has levels considered to be detrimental for their reproduction. Field levels of dioxin and dioxin-like PCBs are therefore suggested as an additional causal factor contributing to the decline of the European eel. 42% of the sampling sites show especially dioxin-like PCB levels exceeding the European consumption level (with a factor 3 on average). Human consumption of eel, especially in these highly contaminated sites, seems unjustified. Copyright © 2011 Elsevier B.V. All rights reserved.

Poly(2-vinyl pyridine)-block-poly(ethylene oxide) featuring a furan group at the block junction-synthesis and functionalization.

PubMed

Rudolph, Tobias; Barthel, Markus J; Kretschmer, Florian; Mansfeld, Ulrich; Hoeppener, Stephanie; Hager, Martin D; Schubert, Ulrich S; Schacher, Felix H

2014-05-01

Furfuryl glycidyl ether (FGE) represents a highly versatile monomer for the preparation of reversibly cross-linkable nanostructured materials via Diels-Alder reactions. Here, the use of FGE for the mid-chain functionalization of a P2VP-b-PEO diblock copolymer is reported. The material features one furan moiety at the block junction, P2VP68 -FGE-b-PEO390 , which can be subsequently addressed in Diels-Alder reactions using maleimide-functionalized counterparts. The presence of the FGE moiety enables the introduction of dyes as model labels or the formation of hetero-grafted brushes as shell on hybrid Au@Polymer nanoparticles. This renders P2VP68 -FGE-b-PEO390 , a powerful tool for selective functionalization reactions, including the modification of surfaces. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Atomic layer deposition overcoating: tuning catalyst selectivity for biomass conversion.

PubMed

Zhang, Hongbo; Gu, Xiang-Kui; Canlas, Christian; Kropf, A Jeremy; Aich, Payoli; Greeley, Jeffrey P; Elam, Jeffrey W; Meyers, Randall J; Dumesic, James A; Stair, Peter C; Marshall, Christopher L

2014-11-03

The terraces, edges, and facets of nanoparticles are all active sites for heterogeneous catalysis. These different active sites may cause the formation of various products during the catalytic reaction. Here we report that the step sites of Pd nanoparticles (NPs) can be covered precisely by the atomic layer deposition (ALD) method, whereas the terrace sites remain as active component for the hydrogenation of furfural. Increasing the thickness of the ALD-generated overcoats restricts the adsorption of furfural onto the step sites of Pd NPs and increases the selectivity to furan. Furan selectivities and furfural conversions are linearly correlated for samples with or without an overcoating, though the slopes differ. The ALD technique can tune the selectivity of furfural hydrogenation over Pd NPs and has improved our understanding of the reaction mechanism. The above conclusions are further supported by density functional theory (DFT) calculations. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Simultaneous concentration and detoxification of lignocellulosic hydrolyzates by vacuum membrane distillation coupled with adsorption.

PubMed

Zhang, Yaqin; Li, Ming; Wang, Yafei; Ji, Xiaosheng; Zhang, Lin; Hou, Lian

2015-12-01

Low sugar concentration and the presence of various inhibitors are the major challenges associated with lignocellulosic hydrolyzates as a fermentation broth. Vacuum membrane distillation (VMD) process can be used to concentrate sugars and remove inhibitors (furans) efficiently, but it's not desirable for the removal of less volatile inhibitors such as acetic acid. In this study, a VMD-adsorption process was proposed to improve the removal of acetic acid, achieving simultaneous concentration and detoxification of lignocellulosic hydrolyzates by one step process. Results showed that sugars were concentrated with high rejections (>98%) and little sugar loss (<2%), with the significant reduction in nearly total furans (99.7%) and acetic acid (83.5%) under optimal operation conditions. Fermentation results showed the ethanol production of hydrolyzates concentrated and detoxified using the VMD-adsorption method were approximately 10-fold greater than from untreated hydrolyzates. Copyright © 2015 Elsevier Ltd. All rights reserved.

Electron-ion dissociative recombination rate constants relevant to the Titan atmosphere and the Interstellar Medium

NASA Astrophysics Data System (ADS)

Osborne, David; Lawson, Patrick; Adams, Nigel

2014-01-01

Following the arrival of Cassini at Titan in 2004, the Titan atmosphere has been shown to contain large complex polycyclic-aromatic hydrocarbons. Since Cassini has provided a great deal of data, there exists a need for kinetic rate data to help with modeling this atmosphere. One type of kinetic data needed is electron-ion dissociative recombination (e-IDR) rate constants. These data are not readily available for larger compounds, such as naphthalene, or oxygen containing compounds, such as 1,4 dioxane or furan. Here, the rate constants for naphthalene, 1,4 dioxane, and furan have been measured and their temperature dependencies are determined when possible, using the University of Georgia's Variable Temperature Flowing Afterglow. The rate constants are compared with those previously published for other compounds; these show trends which illustrate the effects which multi-rings and oxygen heteroatoms substitutions have upon e-IDR rate constants.

The Piancatelli reaction and its variants: recent applications to high added-value chemicals and biomass valorization.

PubMed

Verrier, Charlie; Moebs-Sanchez, Sylvie; Queneau, Yves; Popowycz, Florence

2018-01-31

The Piancatelli reaction, also called the Piancatelli rearrangement, consists in the direct conversion of furfuryl alcohols to cyclopentenone derivatives through a furan ring opening-electrocyclization process. Discovered in the late 70's, this reaction has been scarcely used for more than 40 years but recently has been the focus of particular interest from the scientific community and an increasing number of publications on the topic have emerged in the last few years. The first part of this review provides an overview of the recent achievements in classical Piancatelli reactions, discussing reaction conditions and catalytic systems, whereas the second part focuses on the variants recently developed, including the use of new nucleophiles in the process. Finally, the third part of this review deals with the recent application of this transformation to the production of commodity chemicals from renewable carbon feedstocks based on sugar-derived furanic platforms.

Structure and diffusion of furans and other cellulose-derived compounds in solvents via MD simulation

NASA Astrophysics Data System (ADS)

Rabideau, Brooks; Ismail, Ahmed

2011-03-01

There is now a large push towards the development of energy sources that are both environmentally friendly and sustainable; with the conversion of cellulose derived from biomass into biofuels being one promising route. In this conversion, a variety of intermediary compounds have been identified, which appear critical to successful expansion of the process to an industrial scale. Here we examine the structure and diffusion of these furans and acids derived from cellulose within ionic liquids via molecular dynamic simulation. Ionic liquids have shown the ability to dissolve cellulose with certain `green' benefits over existing, conventional solvents. Specifically, we study the solvation properties of these chemicals by examining the pair correlation functions of solute with solvent, and by exploring the agglomeration and separation of these chemicals from the solvent as well as the hydrogen bonding between species. Additionally, we determine the diffusion constant of these compounds in ionic liquid and aqueous solvents.

Effect of Reclamation on the Skin Layer of Ductile Iron Cast in Furan Molds

NASA Astrophysics Data System (ADS)

Dańko, R.; Holtzer, M.; Górny, M.; Żymankowska-Kumon, S.

2013-11-01

The paper presents the results of investigations of the influence of the quality of molding sand with furan resin hardened by paratoluenesulfonic acid, on the formation of microstructure and surface quality of ductile iron castings. Within the studies different molding sands were used: molding sand prepared with fresh sand and molding sands prepared with reclaimed sands of a different purification degree, determined by the ignition loss value. Various concentrations of sulfur and nitrogen in the sand molds as a function of the ignition loss were shown in the paper. A series of experimental melts of ductile iron in molds made of molding sand characterized by different levels of surface-active elements (e.g., sulfur) and different gas evolution rates were performed. It was shown that there exists a significant effect of the quality of the sand on the formation of the graphite degeneration layer.

Construction of Eu(III)- and Tb(III)-MOFs with photoluminescence for sensing small molecules based on furan-2,5-dicarboxylic acid

NASA Astrophysics Data System (ADS)

Zhao, Shuai; Hao, Xue-Min; Liu, Jia-Lin; Wu, Lin-Wei; Wang, Hao; Wu, Yi-Bo; Yang, Dan; Guo, Wen-Li

2017-11-01

Two isostructural lanthanide MOFs, [Ln3K2(FDA)4(NO3)3(MeCN)2]n (Ln = Eu 1, Tb 2) (H2FDA= furan-2,5-dicarboxylic acid), have been constructed under solvothermal conditions. Structures analyses demonstrate two complexes possess three-dimensional network with monoclinic space group C2/c. The topology analysis shows that the whole framework can be simplified to a 3,8T24 topology constructed from trinuclear {Ln3} as secondary building units (SBUs) without considering K+ ions. Solid state luminescent studies indicate that 1 and 2 show the characteristic red and green emissions of the corresponding Ln3+ ions, respectively. The luminescence lifetimes of 1 and 2 are approximately 1.04 ms and 0.41 ms. In addition, activated 1 exhibits excellent fluorescence sensing for small molecules, especially for nitrobenzene.

Synchrotron-based far-infrared spectroscopy of furan: Rotational analysis of the ν 14 , ν 11 , ν 18 and ν 19 vibrational levels

NASA Astrophysics Data System (ADS)

Tokaryk, D. W.; Culligan, S. D.; Billinghurst, B. E.; van Wijngaarden, J. A.

2011-11-01

Four vibrational levels of the five-membered ring molecule furan (C 4H 4O) have been rotationally analyzed from far-infrared Fourier transform spectra obtained at the Canadian Light Source synchrotron. We found that the low-lying ν14 and ν11 levels at 602.9 and 599.6 cm -1 interact through a second-order Coriolis resonance. This perturbation was characterized through a coupled analysis of the ν14 and ν18 fundamental spectra and the ν18- ν11 band. The ν19 fundamental spectrum was analyzed as well, and the data for all observed bands were combined with previously reported microwave transitions to produce the final fit. The spectra are an excellent demonstration of the high quality of data that can be obtained when far-infrared synchrotron radiation is used as the radiation source in Fourier transform spectroscopy experiments.

Synthesis, anti-inflammatory evaluation in vivo and docking studies of some new 5-(benzo[b]furan-2-ylmethyl)-6-methyl-pyridazin-3(2H)-one derivatives

NASA Astrophysics Data System (ADS)

Boukharsa, Youness; Lakhlili, Wiame; El harti, Jaouad; Meddah, Bouchra; Tiendrebeogo, Ramata Yvette; Taoufik, Jamal; El Abbes Faouzi, My; Ibrahimi, Azeddine; Ansar, M'hammed

2018-02-01

Seven novel 5-(benzo[b]furan-2-ylmethyl)-6-methyl-pyridazin-3(2H)-one derivatives (6a to 6g) have been synthesized by the condensation of appropriate 3-(benzofuran-2-ylmethylene)-4-oxopentanoic acid and hydrazine hydrate in ethanol. Structures of all compounds were elucidated by elemental analysis, IR, 1H NMR and 13C NMR. These compounds were tested for their anti-inflammatory activity in carrageenan-induced rat paw edema model. In silico molecular docking study has been executed to study the binding interactions of the synthesized compounds with COX-2 protein. Compounds 6a, 6b, 6e and 6g showed a good anti-inflammatory activity at 50 mg/kg compared with the indometacin at 10 mg/kg and the aspirin at 150 mg/kg and good binding affinity with COX-2.

Role of the ribose-specific marker furfuryl-amine in the formation of aroma active 1-(furan-2-ylmethyl)-1H-pyrrole (or furfuryl-pyrrole) derivatives.

PubMed

Nikolov, Plamen Y; Yaylayan, Varoujan A

2012-10-10

Furfuryl-pyrroles possess a diverse range of organoleptic properties described as roasted, chocolaty, green, horseradish-like, and mushroom-like and are detected in various foods such as coffee, chocolate, popcorn, and roasted chicken. Although their origin in food was attributed to furfuryl-amine, the latter has not been detected so far in Maillard model systems or in foods. In this study, furfuryl-amine was shown to be formed specifically from ribose through nitrogen atom transfer from the α-amino group of any amino acid. Such a transfer can be achieved through decarboxylation of the Schiff base adduct and isomerization followed by hydrolysis. Through the use of (15)Nα-lysine it was revealed that only the (15)Nα nitrogen atom was incorporated into its structure, indicating a specific role for the carboxylate moiety in the mechanism of its formation. Furthermore, isotope labeling studies have indicated that furfuryl-pyrrole derivatives can be formed by the interaction of 2 mol of furfuryl-amine with 3-deoxyribosone followed by dehydration and cyclization to form 1-(furan-2-yl)-N-{[1-(furan-2-ylmethyl)-1H-pyrrol-2-yl]methylidene}methanamine. After hydrolysis, this intermediate can generate furfuryl-formyl-pyrrole, furfuryl-pyrrole carboxylic acid, and furfuryl-pyrrole. In this study, the furfuryl-amine derivatives were also detected in different coffee beans after pyrolysis and analysis by GC-MS. The potential of these compounds to form in aqueous model systems at a temperature of 120 °C was also demonstrated.

Coordination behavior of new bis Schiff base ligand derived from 2-furan carboxaldehyde and propane-1,3-diamine. Spectroscopic, thermal, anticancer and antibacterial activity studies

NASA Astrophysics Data System (ADS)

Mohamed, Gehad G.; Zayed, Ehab M.; Hindy, Ahmed M. M.

2015-06-01

Novel bis Schiff base ligand, [N1,N3-bis(furan-2-ylmethylene)propane-1,3-diamine], was prepared by the condensation of furan-2-carboxaldehyde with propane-1,3-diamine. Its conformational changes on complexation with transition metal ions [Co(II), Ni(II), Cu(II), Mn(II), Cd(II), Zn(II) and Fe(III)] have been studied on the basis of elemental analysis, conductivity measurements, spectral (infrared, 1H NMR, electronic), magnetic and thermogravimetric studies. The conductance data of the complexes revealed their electrolytic nature suggesting them as 1:2 (for bivalent metal ions) and 1:3 (for Fe(III) ion) electrolytes. The complexes were found to have octahedral geometry based on magnetic moment and solid reflectance measurements. Thermal analysis data revealed the decomposition of the complexes in successive steps with the removal of anions, coordinated water and bis Schiff base ligand. The thermodynamic parameters were calculated using Coats-Redfern equation. The Anticancer screening studies were performed on human colorectal cancer (HCT), hepatic cancer (HepG2) and breast cancer (MCF-7) cell lines. The antimicrobial activity of all the compounds was studied against Gram negative (Escherichia coli and Proteus vulgaris) and Gram positive (Bacillus vulgaris and Staphylococcus pyogones) bacteria. It was observed that the coordination of metal ion has a pronounced effect on the microbial activities of the bis Schiff base ligand. All the metal complexes have shown higher antimicrobial effect than the free bis Schiff base ligand.

Trace Amounts of Furan-2-Carboxylic Acids Determine the Quality of Solid Agar Plates for Bacterial Culture

PubMed Central

Hara, Shintaro; Isoda, Reika; Tahvanainen, Teemu; Hashidoko, Yasuyuki

2012-01-01

Background Many investigators have recognised that a significant proportion of environmental bacteria exist in a viable but non-culturable state on agar plates, and some researchers have also noticed that some of such bacteria clearly recover their growth on matrices other than agar. However, the reason why agar is unsuitable for the growth of some bacteria has not been addressed. Methodology/Principal Findings According to the guide of a bioassay for swarming inhibition, we identified 5-hydroxymethylfuran-2-carboxylic acid (5-HMFA) and furan-2-carboxylic acid (FA) as factors that inhibit bacterial swarming and likely inhibit extracellular polysaccharide production on agar. The furan-2-carboxylic acids 5-HMFA and FA effectively inhibited the swarming and swimming of several environmental bacteria at concentrations of 1.8 and 2.3 µg L−1 (13 and 21 nmol L−1), respectively, which are equivalent to the concentrations of these compounds in 0.3% agar. On Luria-Bertani (LB) plates containing 1.0% agar that had been previously washed with MeOH, a mixture of 5-HMFA and FA in amounts equivalent to their original concentrations in the unwashed agar repressed the swarming of Escherichia coli K12 strain W3110, a representative swarming bacterium. Conclusions/Significance Agar that contains trace amounts of 5-HMFA and FA inhibits the proliferation of some slow-growing or difficult-to-culture bacteria on the plates, but it is useful for single colony isolation due to the ease of identification of swarmable bacteria as the non-swarmed colonies. PMID:22848437

Synthesis and solar-cell applications of novel furanyl-substituted anthracene derivatives

NASA Astrophysics Data System (ADS)

Kivrak, Arif; Er, Ömer Faruk; Kivrak, Hilal; Topal, Yasemin; Kuş, Mahmut; Çamlısoy, Yesim

2017-11-01

At present, novel furanyl-substituted anthracene derivatives; namely 9,10-di(furan-2-yl)anthracene (DFA), 5,5‧-(anthracene-9,10-diyl)bis(furan-2-carbaldehyde) (DAFA) and 2,2‧-((5,5‧-(anthracene-9,10-diyl)bis(furan-5,2-diyl))bis(methanylylidene))dimalononitrile (DCNFA) were designed and synthesized successfully by employing Stille Cross-Coupling, Vilsmeier-Haack and Knoevenagel condensation reactions, respectively. This methodology provides a practical new route for the synthesis of furanyl-substituted anthracene derivatives bearing strong electron-withdrawing groups. The electrochemical and electro-optical properties of these novel furanyl-substituted anthracene derivatives were also examined with strong acceptor-π-donor-π-acceptor interactions. Furthermore, Highest occupied molecular orbital (HOMO), Lowest Unoccupied molecular orbital (LUMO), and band gap (Eg) values were investigated by using spectroscopic methods. Electrochemical and electro-optical properties were calculated and compared to DFA, DAFA and DCNFA. Eg was found as 2.85, 2.71, and 2.33 eV, respectively. Consequently, Organic Solar Cells (OSC) were fabricated to investigate their solar cell performances. The strong electron withdrawing groups did not increase the solar cell performance of furanyl-anthracenes. Surprisingly, DFA was found to exhibit the best OSCs performance (Efficiency = 3.36). As a result, one could note that these novel furanyl-substituted anthracene derivatives are good candidate for the applications of the OSCs. Our results might help in the development of new materials with important electrochemical functions by giving the advantage of designing and further derivatization of new generation small organic molecules for photovoltaic device applications.

Determination of furan precursors and some thermal damage markers in baby foods: ascorbic acid, dehydroascorbic acid, hydroxymethylfurfural and furfural.

PubMed

Mesías-García, Marta; Guerra-Hernández, Eduardo; García-Villanova, Belén

2010-05-26

The presence of ascorbic acid (AA), vitamin C (AA + dehydroascorbic acid (DHAA)) and furfural as potential precursors of furan in commercial fruit and vegetable jarred baby food was studied. Hydroxymethylfurfural (HMF) was also determined and used, together with furfural levels, as markers of thermal damage. AA, calculated DHAA and vitamin C values ranged between 22.4 and 103, 2.9 and 13.8, and 32.1 and 113.2 mg/100 g, respectively, in fruit-based baby food. However, no trace of AA was found in the vegetable-based baby food samples tested, probably because these samples are not enriched in vitamin C and the content of this vitamin in fresh vegetables is destroyed during processing. Furfural values ranged from not detected to 236 microg/100 g, being higher in vegetable samples than in fruit samples possibly because of greater AA degradation favored by a higher pH in the vegetable samples. HMF values (range: not detected-959 microg/100 g), however, were higher in the fruit samples, probably due to greater carbohydrate content degradation and as a consequence of the Maillard reaction, favored by a lower pH in these samples. According to these results, HMF would be the optimum indicator of thermal treatment for fruits, and furfural for vegetables. The higher furfural content of vegetable baby food could be considered an index of greater AA degradation and, therefore, the furan content might be higher in this kind of sample than in fruit-based baby food.

Morbidity study of extruder personnel with potential exposure to brominated dioxins and furans. II. Results of clinical laboratory studies.

PubMed

Ott, M G; Zober, A

1996-12-01

To test whether dioxins affect liver and thyroid function, lipid metabolism and glucose or immunological variables, in workers exposed to brominated dioxins and furans. 34 male production employees (29 were extruder operators) and eight technical support personnel were studied, all of whom were potentially exposed to polybrominated dibenzo-p-dioxins (PBDDs) and furans (PBDFs) during production of resins containing polybrominated diphenyl ethers (PBDEs). Controls were from a similar resin producing plant that did not use PBDEs. Blood samples were analysed for tetra, penta, and hexabrominated congeners, but 2,3,7,8-TBDD was the only exposure measure used in the regression analyses. Seven liver function indicators, five measures of blood lipids and glucose, four haematology and blood coagulation measures, and three measures of thyroid function were examined. None of the variables was statistically related to concentration of 2,3,7,8-TBDD in the regression analyses. Cigarette smoking was related to several outcomes at the 0.05 level: aspartate aminotransferase, alanine aminotransferase, glutamate dehydrogenase (GLDH), erythrocyte sedimentation rate, and white blood cell count. Body mass index was also related to alanine aminotransferase, gamma-glutamyltranspeptidase, cholinesterase, GLDH, cholesterol, triglycerides, high density lipoprotein, low density lipoprotein, and glucose concentrations. No definitive associations between liver, blood lipid, thyroid, or immunological variables and exposure to brominated dioxins or blood lipid concentration of 2,3,7,8-TBDD were found. The study population was small and hence the findings must be interpreted with caution. Nevertheless, these results provide a base for interpreting the results of clinical studies in similarly exposed populations.

Structural analysis of two tetraketones and theoretical investigation of the reactions involved in their preparation

NASA Astrophysics Data System (ADS)

da Silva, Milene Lopes; Teixeira, Róbson Ricardo; de Azevedo Santos, Lucas; Martins, Felipe Terra; Ramalho, Teodorico Castro

2018-03-01

The 2,2'-((5-(4-bromophenyl)furan-2-yl)methylene) bis (5,5-dimethylcyclohexane-1,3-dione) (3) and 2,2'-((5-(4-chlorophenyl)furan-2-yl)methylene) bis (5,5-dimethylcyclohexane-1,3-dione) (4) were prepared in, respectively, 63% and 59% yield, via ZrOCl2ṡ8H2O catalyzed condensation reactions between dimedone and appropriate aldehydes. Their structures were investigated by IR, NMR, and X-ray spectroscopy techniques. The asymmetric unit of tetraketone 3 is composed of just one molecule, while two almost identical crystallographically independent molecules of compound 4 are present there. Compound 3 is conformationally similar to both molecules of 4. The diketone rings assume a half-chair conformation with the flaps oriented toward the same side of the substituent at C1. Each diketone ring is featured by an electronic delocalization path encompassed through the keto-enol moiety. All bond lengths inside this conjugated system are intermediate between those of pure double and single bonds. Furthermore, the furan plane of the substituent at C1 is almost parallel to the bond axes bridging the diketone rings as a consequence of steric hindrance effects between the heterocycle moiety and two hydrogen bonded oxygens. The enol forms of compounds 3 and 4 were noticed via IR and NMR spectroscopies. Furthermore, thermodynamics parameters were calculated in order to interpret the experimental results. In this line, theoretical findings reveal that electronic and solvent effects play an important role in the chemical reactions involved in the preparation of tetraketones.

Electrochemical and photoelectrochemical reduction of furfurals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Choi, Kyoung-Shin; Roylance, John James; Kubota, Stephen R.

Electrochemical cells and photoelectrochemical cells for the reduction of furfurals are provided. Also provided are methods of using the cells to carry out the reduction reactions. Using the cells and methods, furfurals can be converted into furan alcohols or linear ketones.

EMISSIONS OF METALS, CHROMIUM AND NICKEL SPECIES, AND ORGANICS FROM MUNICIPAL WASTEWATER SLUDGE INCINERATORS

EPA Science Inventory

In order to provide data to support regulations on municipal wastewater sludge incineration, emissions of metals, hexavalent chromium, nickel subsulfide, polychlorinated dibenzo-dioxins and furans (PCDD/PCDFs), semivolatile and volatile organic compounds, carbon monoxide (CO)...

PCDD/F TEQ INDICATORS AND THEIR MECHANISTIC IMPLICATIONS

EPA Science Inventory

Stack gas samples from two incinerator facilities with different operating conditions were investigated to find polychlorinated dibenzo-p-dioxin/furan (PCDD/F) toxic equivalent quantity (TEQ) indicators from amongst the 210 PCDD/F isomers. Similarities in isomer patterns were als...

MECHANISTIC RELATIONSHIPS AMONG PCDDS/FS, PCNS, PAHS, CLPHS, AND CLBZS IN MUNICIPAL WASTE INCINERATION

EPA Science Inventory

An extensive investigation was done to understand polychlorinated dibenzo-p-dioxin and furan (PCDD/F) formation mechanisms and their relationship with other organic compounds. PCDD/F, chlorophenols, chlorobenzenes, polyaromatic hydrocarbons and polychlorinated naphthalenes were ...

RISK CHARACTERIZATION OF DIOXINS

EPA Science Inventory

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD; "Dioxin") is the most toxic member of a family of structurally related compounds which are ubiquitous environmental pollutants. The most potent of these, the polyhalogenated dibenzo-p-dioxins and furans, were never produced int...

COMBUSTION CONTROL OF TRACE ORGANIC AIR POLLUTANTS FROM MUNICIPAL WASTE COMBUSTORS

EPA Science Inventory

The US Environmental Protection Agency (EPA) is considering the use of combustion techniques for controlling air emissions of chlorinated dioxins, chlorinated furans, and other trace organics from municipal waste combustion (MWC) facilities. Recommendations for good combustion pr...

RISK CHARACTERIZATION OF DIOXINS FOR EUROTOX 2005

EPA Science Inventory

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD or Dioxin) is the most toxic member of a family of structurally related compounds which are ubiquitous environmental pollutants. The most potent of these classes, the polyhalogenated dibenzo-p-dioxins and furans, were never produced in...

CONTROL OF DIOXIN, FURAN, AND MERCURY EMISSIONS FROM MUNICIPAL WASTE COMBUSTORS

EPA Science Inventory

There is a significant public and scientific concern over the potential risks of air pollution emissions from municipal waste combustors (MWCs). The primary pollutants of concern are polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDDs/PCDFs), and mercury (Hg). Depending on...

Production of xylitol from biomass using an inhibitor-tolerant fungal strain

USDA-ARS?s Scientific Manuscript database

Inhibitory compounds arising from physical–chemical pretreatment of biomass feedstock can interfere with fermentation of biomass sugars to product. A fungus, Coniochaeta ligniaria NRRL30616 improves fermentability of biomass sugars by metabolizing a variety of microbial inhibitors including furan al...

U.S. EPA's National Dioxin Air Monitoring Network: Analytical Issues

EPA Science Inventory

The U.S. EPA has established a National Dioxin Air Monitoring Network (NDAMN) to determine the temporal and geographical variability of atmospheric chlorinated dibenzo-p-dioxins (CDDs), furans (CDFs), and coplanar polychlorinated biphenyls (PCBs) at rural and non-impacted locatio...

ENVIRONMENTAL TECHNOLOGY VERIFICATION (ETV) TEST OF DIOXIN EMISSION MONITORS

EPA Science Inventory

The performance of four dioxin emission monitors including two long-term sampling devices, the DMS (DioxinMonitoringSystem) and AMESA (Adsorption Method for Sampling Dioxins and Furans), and two semi-real-time continuous monitors, RIMMPA-TOFMS (Resonance Ionization with Multi-Mir...

DIOXIN AND FURAN FORMATION ON FLY ASH FROM A MIXTURE OF CHLOROPHENOLS

EPA Science Inventory

To establish the relationship between specific chlorophenol (CP) congener distributions and polychlorinated dibenzo-p-dioxin and dibenzofuran (PCDD/F) products this work investigated the formation of PCDDs/Fs from different CP mixtures passed over fly ash under selected reaction ...

Heterogeneous Organo-Catalysis: Sustainable Pathways to Furanics from Biomass

EPA Science Inventory

Glucose and fructose are among the most abundant plant-derived materials1 and have been converted into useful building units often used in the drug discovery and polymer architecture.2 Unfortunately, most of these conversions require mineral acids and complex heterogeneous cataly...

40 CFR 63.7744 - How do I demonstrate continuous compliance with the work practice standards that apply to me?

Code of Federal Regulations, 2011 CFR

2011-07-01

... procedures used by the scrap supplier for either removing accessible mercury switches or for purchasing... chemical composition of all catalyst binder formulations applied in each furan warm box mold or core making...

40 CFR 63.7744 - How do I demonstrate continuous compliance with the work practice standards that apply to me?

Code of Federal Regulations, 2012 CFR

2012-07-01

... procedures used by the scrap supplier for either removing accessible mercury switches or for purchasing... chemical composition of all catalyst binder formulations applied in each furan warm box mold or core making...

40 CFR 63.7744 - How do I demonstrate continuous compliance with the work practice standards that apply to me?

Code of Federal Regulations, 2014 CFR

2014-07-01

... procedures used by the scrap supplier for either removing accessible mercury switches or for purchasing... chemical composition of all catalyst binder formulations applied in each furan warm box mold or core making...

40 CFR 63.7744 - How do I demonstrate continuous compliance with the work practice standards that apply to me?

Code of Federal Regulations, 2013 CFR

2013-07-01

... procedures used by the scrap supplier for either removing accessible mercury switches or for purchasing... chemical composition of all catalyst binder formulations applied in each furan warm box mold or core making...

Fundamental studies of catalytic processing of synthetic liquids. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Watson, P.R.

1994-06-15

Liquids derived from coal contain relatively high amounts of oxygenated organic compounds, mainly in the form of phenols and furans that are deleterious to the stability and quality of these liquids as fuels. Hydrodeoxygenation (HDO) using Mo/W sulfide catalysts is a promising method to accomplish this removal, but our understanding of the reactions occurring on the catalyst surface during HDO is very limited. Rather than attempting to examine the complexities of real liquids and catalysts we have adopted an approach here using model systems amenable to surface-sensitive techniques that enable us to probe in detail the fundamental processes occurring duringmore » HDO at the surfaces of well-defined model catalysts. The results of this work may lead to the development of more efficient, selective and stable catalysts. Above a S/Mo ratio of about 0.5 ML, furan does not adsorb on sulfided Mo surfaces; as the sulfur coverage is lowered increasing amounts of furan can be adsorbed. Temperature-programmed reaction spectroscopy (TPRS) reveals that C-H, C-C and C-O bond scission occurs on these surfaces. Auger spectra show characteristic changes in the nature and amount of surface carbon. Comparisons with experiments carried out with CO, H{sub 2} and alkenes show that reaction pathways include -- direct abstraction of CO at low temperatures; cracking and release of hydrogen below its normal desorption temperature; dehydrogenatin of adsorbed hydrocarbon fragments; recombination of C and O atoms and dissolution of carbon into the bulk at high temperatures. Performing the adsorption or thermal reaction in 10{sup {minus}5} torr of hydrogen does not change the mode of reaction significantly.« less

Furan-based benzene mono- and dicarboxylic acid derivatives as multiple inhibitors of the bacterial Mur ligases (MurC-MurF): experimental and computational characterization.

PubMed

Perdih, Andrej; Hrast, Martina; Pureber, Kaja; Barreteau, Hélène; Grdadolnik, Simona Golič; Kocjan, Darko; Gobec, Stanislav; Solmajer, Tom; Wolber, Gerhard

2015-06-01

Bacterial resistance to the available antibiotic agents underlines an urgent need for the discovery of novel antibacterial agents. Members of the bacterial Mur ligase family MurC-MurF involved in the intracellular stages of the bacterial peptidoglycan biosynthesis have recently emerged as a collection of attractive targets for novel antibacterial drug design. In this study, we have first extended the knowledge of the class of furan-based benzene-1,3-dicarboxylic acid derivatives by first showing a multiple MurC-MurF ligase inhibition for representatives of the extended series of this class. Steady-state kinetics studies on the MurD enzyme were performed for compound 1, suggesting a competitive inhibition with respect to ATP. To the best of our knowledge, compound 1 represents the first ATP-competitive MurD inhibitor reported to date with concurrent multiple inhibition of all four Mur ligases (MurC-MurF). Subsequent molecular dynamic (MD) simulations coupled with interaction energy calculations were performed for two alternative in silico models of compound 1 in the UMA/D-Glu- and ATP-binding sites of MurD, identifying binding in the ATP-binding site as energetically more favorable in comparison to the UMA/D-Glu-binding site, which was in agreement with steady-state kinetic data. In the final stage, based on the obtained MD data novel furan-based benzene monocarboxylic acid derivatives 8-11, exhibiting multiple Mur ligase (MurC-MurF) inhibition with predominantly superior ligase inhibition over the original series, were discovered and for compound 10 it was shown to possess promising antibacterial activity against S. aureus. These compounds represent novel leads that could by further optimization pave the way to novel antibacterial agents.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zeng, Xiaofei; Borole, Abhijeet P.; Pavlostathis, Spyros G.

Furanic and phenolic compounds, formed during the pretreatment of lignocellulosic biomass, are problematic byproducts in down-stream biofuel processes. A microbial electrolysis cell (MEC) is an alternative technology to handle furanic and phenolic compounds and produce renewable hydrogen (H 2). In this study, we evaluated the performance of a continuous-flow bioanode MEC fed with furanic and phenolic compounds at different operating conditions. All hydraulic retention times (HRTs) tested (6-24 h) resulted in complete transformation of the parent compounds at an organic loading rate (OLR) of 0.2g L -1 per d and applied voltage of 0.6 V. Increasing the OLR to 0.8more » g L -1 per d at an HRT of 6h resulted in an increased H 2 production rate from 0.07 to 0.14 L L anode 1 per d, but an OLR of 3.2 g L -1 per d did not lead to a higher H 2 production rate. Significant methane production was observed at an OLR of 3.2 g L -1 per d. The lack of increased H 2 production at the highest OLR tested was due to a limited rate of exoelectrogenesis but not fermentation, evidenced by the accumulation of high acetate levels and higher growth of fermenters and methanogens over exoelectrogens. Increasing applied voltage from 0.6 to 1.0V at an OLR of 3.2 g L -1 per d and HRT of 6h enhanced exoelectrogenesis and resulted in a 1.7-fold increase of H 2 production. Under all operating conditions, more than 90% of the biomass was biofilm-associated. Lastly, the present study provides new insights into the performance of continuous-flow bioelectrochemical systems fed with complex waste streams resulting from the pretreatment of lignocellulosic biomass.« less

Morbidity study of extruder personnel with potential exposure to brominated dioxins and furans. II. Results of clinical laboratory studies.

PubMed Central

Ott, M G; Zober, A

1996-01-01

OBJECTIVE: To test whether dioxins affect liver and thyroid function, lipid metabolism and glucose or immunological variables, in workers exposed to brominated dioxins and furans. METHODS: 34 male production employees (29 were extruder operators) and eight technical support personnel were studied, all of whom were potentially exposed to polybrominated dibenzo-p-dioxins (PBDDs) and furans (PBDFs) during production of resins containing polybrominated diphenyl ethers (PBDEs). Controls were from a similar resin producing plant that did not use PBDEs. Blood samples were analysed for tetra, penta, and hexabrominated congeners, but 2,3,7,8-TBDD was the only exposure measure used in the regression analyses. Seven liver function indicators, five measures of blood lipids and glucose, four haematology and blood coagulation measures, and three measures of thyroid function were examined. RESULTS: None of the variables was statistically related to concentration of 2,3,7,8-TBDD in the regression analyses. Cigarette smoking was related to several outcomes at the 0.05 level: aspartate aminotransferase, alanine aminotransferase, glutamate dehydrogenase (GLDH), erythrocyte sedimentation rate, and white blood cell count. Body mass index was also related to alanine aminotransferase, gamma-glutamyltranspeptidase, cholinesterase, GLDH, cholesterol, triglycerides, high density lipoprotein, low density lipoprotein, and glucose concentrations. No definitive associations between liver, blood lipid, thyroid, or immunological variables and exposure to brominated dioxins or blood lipid concentration of 2,3,7,8-TBDD were found. CONCLUSIONS: The study population was small and hence the findings must be interpreted with caution. Nevertheless, these results provide a base for interpreting the results of clinical studies in similarly exposed populations. PMID:8994404

Final Technical Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Resasco, Daniel; Lobban, Lance; Crossley, Steven

The goal was to develop a biomass conversion process that optimizes fractionation and conversion to maximize Carbon efficiency and Hydrogen consumption to obtain drop-in fuels. Selective fractionation of raw biomass was obtained via multi-stage thermal fractionation to produce different streams that are enriched in a particular chemical family (acids, furanics or phenolics). These streams were later catalytically upgraded in both liquid and vapor phase to perform C-C bond formation and hydrodeoxygenation. Among various upgrading strategies investigated we have identified an effective path in which cyclopentanone is a crucial intermediate that can be derived from furfural and other furanics obtained inmore » high concentrations from this thermal staged process. Cyclopentanone is a very versatile molecule, which can couple with itself to product high quality jet-fuel, or couple with phenolic or furanics to create long chain molecules. These (mono-oxygenated) compounds in the correct molecular weight fuel range can be hydrotreated to direct drop-in fuels. Interestingly, we have found that the conversion of furfural to cyclopentanone is not affected by the presence of acetic acid, and, more interestingly, it is enhanced by the presence of water. These are very significant findings, since water and acetic acid are always present in all streams from the primary conversion stage. These results have allowed to complete detailed life-cycle assessment and techno-economic analysis that have been back-fed to the experimentalists to refine the catalyst selection and process operations with the objective of maximizing C efficiency at minimum H utilization. These combined investigations have opened the possibility of an economically and technologically effective process that could result in commercial fuels produced from renewable sources at a cost that might be competitive with fossil fuels.« less

Reproductive success and contaminant associations in tree swallows (Tachycineta bicolor) used to assess a Beneficial Use Impairment in U.S. and Binational Great Lakes’ Areas of Concern

USGS Publications Warehouse

Custer, Christine M.; Custer, Thomas W.; Etterson, Matthew A.; Dummer, Paul; Goldberg, Diana R.; Franson, J. Christian

2018-01-01

During 2010-2014, tree swallow (Tachycineta bicolor) reproductive success was monitored at 68 sites across all 5 Great Lakes, including 58 sites located within Great Lakes Areas of Concern (AOCs) and 10 non-AOCs. Sample eggs were collected from tree swallow clutches and analyzed for contaminants including polychlorinated biphenyls (PCBs), dioxins and furans, polybrominated diphenyl ethers, and 34 other organic compounds. Contaminant data were available for 360 of the clutches monitored. Markov chain multistate modeling was used to assess the importance of 5 ecological variables and 11 of the dominant contaminants in explaining the pattern of egg and nestling failure rates. Four of 5 ecological variables (Female Age, Date within season, Year, and Site) were important explanatory variables. Of the 11 contaminants, only total dioxin and furan toxic equivalents (TEQs) explained a significant amount of the egg failure probabilities. Neither total PCBs nor PCB TEQs explained the variation in egg failure rates. In a separate analysis, polycyclic aromatic hydrocarbon exposure in nestling diet, used as a proxy for female diet during egg laying, was significantly correlated with the daily probability of egg failure. The 8 sites within AOCs which had poorer reproduction when compared to 10 non-AOC sites, the measure of impaired reproduction as defined by the Great Lakes Restoration Initiative, were associated with exposure to dioxins and furan TEQs, PAHs, or depredation. Only 2 sites had poorer reproduction than the poorest performing non-AOC. Using a classic (non-modeling) approach to estimating reproductive success, 82% of nests hatched at least 1 egg, and 75% of eggs laid, excluding those collected for contaminant analyses, hatched.

Reproductive success and contaminant associations in tree swallows (Tachycineta bicolor) used to assess a Beneficial Use Impairment in U.S. and Binational Great Lakes' Areas of Concern.

PubMed

Custer, Christine M; Custer, Thomas W; Etterson, Matthew A; Dummer, Paul M; Goldberg, Diana; Franson, J Christian

2018-05-01

During 2010-2014, tree swallow (Tachycineta bicolor) reproductive success was monitored at 68 sites across all 5 Great Lakes, including 58 sites located within Great Lakes Areas of Concern (AOCs) and 10 non-AOCs. Sample eggs were collected from tree swallow clutches and analyzed for contaminants including polychlorinated biphenyls (PCBs), dioxins and furans, polybrominated diphenyl ethers, and 34 other organic compounds. Contaminant data were available for 360 of the clutches monitored. Markov chain multistate modeling was used to assess the importance of 5 ecological variables and 11 of the dominant contaminants in explaining the pattern of egg and nestling failure rates. Four of 5 ecological variables (Female Age, Date within season, Year, and Site) were important explanatory variables. Of the 11 contaminants, only total dioxin and furan toxic equivalents (TEQs) explained a significant amount of the egg failure probabilities. Neither total PCBs nor PCB TEQs explained the variation in egg failure rates. In a separate analysis, polycyclic aromatic hydrocarbon exposure in nestling diet, used as a proxy for female diet during egg laying, was significantly correlated with the daily probability of egg failure. The 8 sites within AOCs which had poorer reproduction when compared to 10 non-AOC sites, the measure of impaired reproduction as defined by the Great Lakes Restoration Initiative, were associated with exposure to dioxins and furan TEQs, PAHs, or depredation. Only 2 sites had poorer reproduction than the poorest performing non-AOC. Using a classic (non-modeling) approach to estimating reproductive success, 82% of nests hatched at least 1 egg, and 75% of eggs laid, excluding those collected for contaminant analyses, hatched.

Furan-based benzene mono- and dicarboxylic acid derivatives as multiple inhibitors of the bacterial Mur ligases (MurC-MurF): experimental and computational characterization

NASA Astrophysics Data System (ADS)

Perdih, Andrej; Hrast, Martina; Pureber, Kaja; Barreteau, Hélène; Grdadolnik, Simona Golič; Kocjan, Darko; Gobec, Stanislav; Solmajer, Tom; Wolber, Gerhard

2015-06-01

Bacterial resistance to the available antibiotic agents underlines an urgent need for the discovery of novel antibacterial agents. Members of the bacterial Mur ligase family MurC-MurF involved in the intracellular stages of the bacterial peptidoglycan biosynthesis have recently emerged as a collection of attractive targets for novel antibacterial drug design. In this study, we have first extended the knowledge of the class of furan-based benzene-1,3-dicarboxylic acid derivatives by first showing a multiple MurC-MurF ligase inhibition for representatives of the extended series of this class. Steady-state kinetics studies on the MurD enzyme were performed for compound 1, suggesting a competitive inhibition with respect to ATP. To the best of our knowledge, compound 1 represents the first ATP-competitive MurD inhibitor reported to date with concurrent multiple inhibition of all four Mur ligases (MurC-MurF). Subsequent molecular dynamic (MD) simulations coupled with interaction energy calculations were performed for two alternative in silico models of compound 1 in the UMA/ d-Glu- and ATP-binding sites of MurD, identifying binding in the ATP-binding site as energetically more favorable in comparison to the UMA/ d-Glu-binding site, which was in agreement with steady-state kinetic data. In the final stage, based on the obtained MD data novel furan-based benzene monocarboxylic acid derivatives 8- 11, exhibiting multiple Mur ligase (MurC-MurF) inhibition with predominantly superior ligase inhibition over the original series, were discovered and for compound 10 it was shown to possess promising antibacterial activity against S. aureus. These compounds represent novel leads that could by further optimization pave the way to novel antibacterial agents.

COMBUSTION CONTROL OF ORGANIC EMISSIONS FROM MUNICIPAL WASTE COMBUSTORS

EPA Science Inventory

More than two decades ago, researchers identified benzo(a)pyrene and other organic species in the emissions from incineration of solid waste. Chlorinated dibenzo-p-dioxins and-furans (CDD/CDF) were first detected in municipal waste combustor (MWC) emissions in 1977. Since then, C...

PREDICTION OF DIOXIN/FURAN INCINERATOR EMISSIONS USING LOW-MOLECULAR-WEIGHT VOLATILE PRODUCTS OF INCOMPLETE COMBUSTION

EPA Science Inventory

Emissions of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDDs/PCDFs) from incinerators and other stationary combustion sources are of environmental concern because of the toxicity of certain PCDD/PCDF congeners. Measurement of trace levels of PCDDs/PCDFs...

ORIGIN OF CARBON IN POLYCHLORINATED DIOXINS AND FURANS FORMED DURING SOOTING COMBUSTION

EPA Science Inventory

The paper discusses results of an investigation on the importance of solid- and gas-phase carbon precursors for the formation of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDDs/Fs) during sooting combustion. Experiments were performed in an entrained flow reactor (EFR)...

40 CFR 721.3815 - Furan, 2-(ethoxymethyl)- tetrahydro-.

Code of Federal Regulations, 2010 CFR

2010-07-01

... new information, and any information on methods for protecting against such risk, into a Material...-. 721.3815 Section 721.3815 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC... substance is any manner or method of manufacture, import, or processing associated with any use of this...

Synthesis and Characterization of Partial Biobased Furan Polyamides

DTIC Science & Technology

2014-02-01

Approved for public release; distribution is unlimited. NOTICES Disclaimers The...Weapons and Materials Research Directorate, ARL Approved for public release; distribution is unlimited...ii REPORT DOCUMENTATION PAGE Form Approved OMB No. 0704-0188 Public reporting burden for this collection of information is estimated to average

Catalysis in the Diels-Alder Cycloaddition of Biomass-Derived Furan and Methyl Acrylate by Transition Metal Oxide Surfaces.

NASA Astrophysics Data System (ADS)

Salavati-Fard, Taha; Jenness, Glen; Caratzoulas, Stavros; Doren, Douglas

Using computational methods, the catalytic effects of oxide surfaces on the Diels-Alder reaction between biomass-derived furan and methyl acrylate are investigated. The cycloadduct can be dehydrated later to produce methyl benzoic which is an important step toward benzoic acid production. Different systems such as clean, partially hydroxylated and fully hydroxylated ZrO2 are considered. The Langmuir and Eley-Rideal mechanisms are studied, as well. Our calculations show that the oxide surfaces catalyze the reaction significantly through the interaction of metal sites with the electron-poor reactant. The calculations are interpreted by making use of the total and projected electronic density of states and band structure of the catalyst. This material is based on work supported as part of the Catalysis Center for Energy Innovation, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Award Number DE-SC0001004.

Chlorinated Dioxins and Furans from Kelp and Copper Sulfate ...

EPA Pesticide Factsheets

In 2002, dioxins were discovered in animal feed ingredients during a random sampling by Irish officials and subsequently traced to particular mineral supplements produced at a Minnesota plant in the United States. These products sold under the names of SQM Mineral Products and Carbosan Mineral Products provide trace minerals complexed to polysaccharides for delivery of trace minerals. The products were voluntarily recalled by the company until the source of the dioxins could be identified and the dioxins eliminated from the supplements. Preliminary investigations by the company and federal agencies indicated that the dioxins were apparently produced during the manufacturing process of supplements containing copper, zinc, manganese, magnesium and iron. Additional studies were initiated to identify the specific ingredients required for dioxin formation and to provide further insight into the conditions necessary for their production. Citation: Ferrario, J.; Byrne, C.; Winters, D.; Boone, T.; Vigo, C.; Dupuy, A.; 2003. Chlorinated Dioxins and Furans from Kelp and Copper Sulfate: Initial Investigations of Dioxin Formation in Mineral Feed Supplements. Organohalogen Compounds 63, 183-186.

Preparation and Characterization of a Small Library of Thermally-Labile End-Caps for Variable-Temperature Triggering of Self-Immolative Polymers.

PubMed

Taimoory, S Maryamdokht; Sadraei, S Iraj; Fayoumi, Rose Anne; Nasri, Sarah; Revington, Matthew; Trant, John F

2018-04-20

The reaction between furans and maleimides has increasingly become a method of interest as its reversibility makes it a useful tool for applications ranging from self-healing materials, to self-immolative polymers, to hydrogels for cell culture and for the preparation of bone repair. However, most of these applications have relied on simple monosubstituted furans and simple maleimides and have not extensively evaluated the potential thermal variability inherent in the process that is achievable through simple substrate modification. A small library of cycloadducts suitable for the above applications was prepared, and the temperature dependence of the retro-Diels-Alder processes was determined through in situ 1 H NMR analyses complemented by computational calculations. The practical range of the reported systems ranges from 40 to >110 °C. The cycloreversion reactions are more complex than would be expected based on simple trends expected based on frontier molecular orbital analyses of the materials.

A new β-glucosidase producing yeast for lower-cost cellulosic ethanol production from xylose-extracted corncob residues by simultaneous saccharification and fermentation.

PubMed

Liu, Z Lewis; Weber, Scott A; Cotta, Michael A; Li, Shi-Zhong

2012-01-01

This study reports a new yeast strain of Clavispora NRRL Y-50464 that is able to utilize cellobiose as sole source of carbon and produce sufficient native β-glucosidase enzyme activity for cellulosic ethanol production using SSF. In addition, this yeast is tolerant to the major inhibitors derived from lignocellulosic biomass pre-treatment such as 2-furaldehyde (furfural) and 5-(hydroxymethyl)-2-furaldehyde (HMF), and converted furfural into furan methanol in less than 12h and HMF into furan-2,5-dimethanol within 24h in the presence of 15 mM each of furfural and HMF. Using xylose-extracted corncob residue as cellulosic feedstock, an ethanol production of 23 g/l was obtained using 25% solids loading at 37 °C by SSF without addition of exogenous β-glucosidase. Development of this yeast aids renewable biofuels development efforts for economic consolidated SSF bio-processing. Published by Elsevier Ltd.

Analysis of by-product formation and sugar monomerization in sugarcane bagasse pretreated at pilot plant scale: differences between autohydrolysis, alkaline and acid pretreatment.

PubMed

van der Pol, Edwin; Bakker, Rob; van Zeeland, Alniek; Sanchez Garcia, David; Punt, Arjen; Eggink, Gerrit

2015-04-01

Sugarcane bagasse is an interesting feedstock for the biobased economy since a large fraction is polymerized sugars. Autohydrolysis, alkaline and acid pretreatment conditions combined with enzyme hydrolysis were used on lignocellulose rich bagasse to acquire monomeric. By-products found after pretreatment included acetic, glycolic and coumaric acid in concentrations up to 40, 21 and 2.5 g/kg dry weight bagasse respectively. Alkaline pretreated material contained up to 45 g/kg bagasse DW of sodium. Acid and autohydrolysis pretreatment results in a furan formation of 14 g/kg and 25 g/kg DW bagasse respectively. Enzyme monomerization efficiencies of pretreated solid material after 72 h were 81% for acid pretreatment, 77% for autohydrolysis and 57% for alkaline pretreatment. Solid material was washed with superheated water to decrease the amount of by-products. Washing decreased organic acid, phenol and furan concentrations in solid material by at least 60%, without a major sugar loss. Copyright © 2015 Elsevier Ltd. All rights reserved.

Opioid receptor probes derived from cycloaddition of the hallucinogen natural product salvinorin A.

PubMed

Lozama, Anthony; Cunningham, Christopher W; Caspers, Michael J; Douglas, Justin T; Dersch, Christina M; Rothman, Richard B; Prisinzano, Thomas E

2011-04-25

As part of our continuing efforts toward more fully understanding the structure-activity relationships of the neoclerodane diterpene salvinorin A, we report the synthesis and biological characterization of unique cycloadducts through [4+2] Diels-Alder cycloaddition. Microwave-assisted methods were developed and successfully employed, aiding in functionalizing the chemically sensitive salvinorin A scaffold. This demonstrates the first reported results for both cycloaddition of the furan ring and functionalization via microwave-assisted methodology of the salvinorin A skeleton. The cycloadducts yielded herein introduce electron-withdrawing substituents and bulky aromatic groups into the C-12 position. Kappa opioid (KOP) receptor space was explored through aromatization of the bent oxanorbornadiene system possessed by the cycloadducts to a planar phenyl ring system. Although dimethyl- and diethylcarboxylate analogues 5 and 6 retain some affinity and selectivity for KOP receptors and are full agonists, their aromatized counterparts 13 and 14 have reduced affinity for KOP receptors. The methods developed herein signify a novel approach toward rapidly probing the structure-activity relationships of furan-containing natural products.

Reforming and decomposition of glucose in an aqueous phase

NASA Technical Reports Server (NTRS)

Amin, S.; Reid, R. C.; Modell, M.

1975-01-01

Exploratory experiments have been carried out to study the decomposition of glucose, a typical carbohydrate, in a high temperature-high pressure water reactor. The objective of the study was to examine the feasibility of such a process to decompose cellulosic waste materials in long-term space missions. At temperatures below the critical point of water, glucose decomposed to form liquid products and char. Little gas was noted with or without reforming catalysts present. The rate of the primary glucose reaction increased significantly with temperature. Partial identification of the liquid phase was made and the C:H:O ratios determined for both the liquid and solid products. One of the more interesting results from this study was the finding that when glucose was injected into a reactor held at the critical temperature (and pressure) of water, no solid products formed. Gas production increased, but the majority of the carbon was found in soluble furans (and furan derivatives). This significant result is now being investigated further.

Alternative fuel production by catalytic hydroliquefaction of solid municipal wastes, primary sludges and microalgae.

PubMed

Lemoine, F; Maupin, I; Lemée, L; Lavoie, J-M; Lemberton, J-L; Pouilloux, Y; Pinard, L

2013-08-01

An alternative fuel production was investigated through catalytic hydroliquefaction of three different carbonaceous sources: solid municipal wastes (MW), primary sludges (PS), and microalgae (MA). The reaction was carried out under hydrogen pressure, at different temperatures (330, 380 and 450°C), with a Raney nickel catalyst and two different hydrogen donor solvents: a "fossil solvent" (tetralin) and a "green solvent" (2-methyl-hydro-furan). The feeds analyses (TDA-TGA, ICP-AES, lipids quantification) showed that MW and PS had similar characteristics and physico-chemical properties, but different from those of MA. The hydroliquefaction of these feeds allowed to obtain high oil yields, with a significant energetic value, similar to that of a bio-petroleum. 2-methyl-hydro-furan was more efficient than tetralin for the treatment of the strongly bio-degraded biomasses MW and PS, while better results were obtained with tetralin in the case of MA. Copyright © 2013 Elsevier Ltd. All rights reserved.

Catalytic hydrolysis of cellulose into furans

NASA Astrophysics Data System (ADS)

Shi, Chengmei; Tao, Furong; Cui, Yuezhi

2016-12-01

Chromium chloride in 4-(3-methylimidazolium-1-yl)butane-1-sulfonic acid hydrogen sulfate (IL-1) was found to effectively catalyze the hydrolysis of microcrystalline cellulose (MCC) at 150°C for 300 min to achieve 87.8% conversion to a slate of products. With a catalytic amount of CrCl3, the yields of 5-hydroxymethyl furfural (HMF) and furfural were up to 32.4 and 15.2%, respectively, small molecules levulinic acid (LA, 10.8%) and the total reducing sugars (TRS, 10.7%) were also generated. Through LC-MSD analysis and mass spectra, dimer of furan compounds as the main by-products were speculated, and the components of gas products were methane, ethane, CO, CO2, and H2. We suggested that IL-1 and CrCl3 exhibited a coordination interaction; the formation of the intermediate via the hydride shift played a key role in the formation of HMF. The catalyst was recycled and exhibited constant activity for five successive trials.

ENHANCED FORMATION OF DIOXINS AND FURANS FROM COMBUSTION DEVICES BY ADDITION OF TRACE QUANTITIES OF BROMINE

EPA Science Inventory

Past pilot-scale experimental studies have shown a dramatic increase in the formation of certain chlorinated products of incomplete combustion (PICs) caused by the addition of trace amounts of bromine (Br). Emissions of trichloroethylene and tetrachloorethylene, generated as PICs...

MODELLING OF POLYCHLORINATED-DIOXIN AND -FURAN CONGENER PROFILES FROM MUNICIPAL WASTE COMBUSTION

EPA Science Inventory

The paper discusses a model, based on experimental data, that was developed to describe the profile of polychlorinated dibenzo-p-dioxin (PCDD) and polychlorinated dibenzofuran (PCDF) congeners formed in the duct region of a pilot-scale combustor simulating large-scale municipal w...

A microwave assisted intramolecular-furan-Diels-Alder approach to 4-substituted indoles.

PubMed

Petronijevic, Filip; Timmons, Cody; Cuzzupe, Anthony; Wipf, Peter

2009-01-07

The key steps of a versatile new protocol for the convergent synthesis of 3,4-disubstituted indoles are the addition of an alpha-lithiated alkylaminofuran to a carbonyl compound, a microwave-accelerated intramolecular Diels-Alder cycloaddition and an in situ double aromatization reaction.

40 CFR 63.1207 - What are the performance testing requirements?

Code of Federal Regulations, 2010 CFR

2010-07-01

... operating conditions that are most likely to reflect daily maximum operating variability, similar to a... operating variability, similar to a dioxin/furan compliance test; (B) You have not changed the design or... document the temperature location measurement in the comprehensive performance test plan, as required by...

Framework for Application of the Toxicity Equivalence Methodology for Polychlorinated Dioxins, Furans, and Biphenyls in Ecological Risk Assessment (Final)

EPA Science Inventory

Polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), and biphenyls (PCBs) are persistent contaminants found widely in the environment. Several of these compounds bioaccumulate in the tissues of fish, birds, and mammals and have been shown to cause mortality and adver...

Synthesis of the insecticide prothrin and its analogues from biomass-derived 5-(Chloromethyl) furfural

USDA-ARS?s Scientific Manuscript database

Prothrin, a synthetic pyrethroid insecticide, was synthesized from the biomass-derived platform chemical 5 (chloromethyl)furfural in six steps and overall 65% yield. Two structural analogues of prothrin were also prepared following the same synthetic approach. Preliminary testing of these furan-base...

NORTH AMERICA'S SOUND MANAGEMENT OF CHEMICALS INITIATIVE: APPLICATION OF SELECTION CRITERIA TO DIOXINS/FURANS, HEXACHLOROBENZENE, AND HEXACHLOROCYCLOHEXANES

EPA Science Inventory

In October 1997, the North American Commission for Environmental Cooperation finalized its process for identifying candidate substances for regional action under the Sound Management of Chemicals Initiative. Regional action plans will be prepared if substantive risk to human he...

The cost-effective synthesis of furan- and thienyl-based microporous polyaminals for adsorption of gases and organic vapors.

PubMed

Li, Guiyang; Zhang, Biao; Yan, Jun; Wang, Zhonggang

2016-01-21

This work reveals that furfural and 2-thenaldehyde can readily react with melamine via "one-step" polycondensation to yield hyper-cross-linked sulfur-, nitrogen- and oxygen-rich microporous polyaminals with promising applications in adsorption of gases and toxic organic vapors.

PAPER FIBERS AS A CARBON SOURCE FOR THE DE NOVO FORMATION OF POLYCHLORINATED DIOXINS AND FURANS

EPA Science Inventory

Formation of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzefurans (PCDDs/Fs) from carbons that were produced from pyrolysis of paper fibers and from a wood charcoal was investigated experimentally. Fibers obtained from a filter paper were pyrolyzed at 300 and 800 d...

A REGIONAL MODEL FOR PCDD/F'S BASED ON A PHOTOCHEMICAL MODEL FOR AIR QUALITY AND PARTICULATE MATTER

EPA Science Inventory

How important is gas to particle partitioning in predicting air concentrations and deposition of Poly-Chlorinated Dibenzo-p-Dioxins and Furans (PCDD/F's)? Literature indicates that the fate of emissions changes because the summation of atmospheric processes has a different balanc...

Formation of furan fatty alkyl esters from their bis-epoxide fatty esters

USDA-ARS?s Scientific Manuscript database

Epoxidation of vegetable oils and consecutive epoxide ring-opening reaction is a widely investigated path for producing biobased lubricants and polymers. The reaction mechanism and products are considered well-studied and known. In the current study, the reactions of epoxidized alkyl soyate with fou...

Synthesis and Characterization of Furanic Compounds

DTIC Science & Technology

2013-09-01

trifluoroacetic acid, 1.6-M solution of BuLi in hexane, dichloromethane, sodium bicarbonate, pyridinium chlorochromate, potassium permanganate , sodium...intermediate, 2,5-diformylfuran (2.29 g, 18.47 mmol), was oxidized in a 100-mL round-bottom flask with potassium permanganate (4.47 g, 153.1 mmol) in a NaOH

40 CFR 60.1885 - What must I include in my annual report?

Code of Federal Regulations, 2011 CFR

2011-07-01

... monitoring system (§ 60.1850(a)(1)). (d) For municipal waste combustion units that use activated carbon for controlling dioxins/furans or mercury emissions, include four records: (1) The average carbon feed rates... municipal waste combustion units only, nitrogen oxides emissions. (3) Carbon monoxide emissions. (4) Load...

40 CFR 60.1410 - What must I include in my annual report?

Code of Federal Regulations, 2011 CFR

2011-07-01

...) For municipal waste combustion units that use activated carbon for controlling dioxins/furans or mercury emissions, include four records: (1) The average carbon feed rates recorded during the most recent..., nitrogen oxides emissions. (3) Carbon monoxide emissions. (4) Load level of the municipal waste combustion...

A microwave assisted intramolecular-furan-Diels–Alder approach to 4-substituted indoles†

PubMed Central

Petronijevic, Filip; Timmons, Cody; Cuzzupe, Anthony; Wipf, Peter

2009-01-01

The key steps of a versatile new protocol for the convergent synthesis of 3,4-disubstituted indoles are the addition of an α-lithiated alkylaminofuran to a carbonyl compound, a microwave-accelerated intramolecular Diels–Alder cycloaddition and an in situ double aromatization reaction. PMID:19082013

AN EVALUATION OF THREE EMPIRICAL AIR-TO-LEAF MODELS FOR POLYCHLORINATED DIBENZO-P-DIOXINS AND DIBENZOFURANS

EPA Science Inventory

Three empirical air-to-leaf models for estimating grass concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans (abbreviated dioxins and furans) from air concentrations of these compounds are described and tested against two field data sets. All are empirical in th...

Gold catalysed synthesis of 3-alkoxyfurans at room temperature.

PubMed

Pennell, Matthew N; Foster, Robert W; Turner, Peter G; Hailes, Helen C; Tame, Christopher J; Sheppard, Tom D

2014-02-09

Synthetically important 3-alkoxyfurans can be prepared efficiently via treatment of acetal-containing propargylic alcohols (obtained from the addition of 3,3-diethoxypropyne to aldehydes) with 2 mol% gold catalyst in an alcohol solvent at room temperature. The resulting furans show useful reactivity in a variety of subsequent transformations.

The Crystal and Molecular Structure of Dianhydrogossypol

USDA-ARS?s Scientific Manuscript database

Dianhydrogossypol (4,4'-dihydroxy-5,5'-diisopropyl-7,7'-dimethyl-bis(3H-naphtho[1,8-bc]furan-3-one)) was made by refluxing gossypol in m-xylene. Proton NMR confirmed that complete conversion was achieved over several hours. Single crystals were obtained by slow evaporation of the product from dichl...

PERFORMANCE OF THE CAPE TECHNOLOGIES DF1 DIOXIN/FURAN IMMUNOASSAY KIT FOR SOIL AND SEDIMENT SAMPLES

EPA Science Inventory

A demonstration of screening technologies for determining the presence of dioxin and dioxin-like compounds in soil and sediment was conducted under the U.S. Environmental Protection Agency’s (EPA’s) Superfund Innovative Technology Evaluation Program in Saginaw, Michigan in 2004. ...

40 CFR 60.1805 - Must I meet other requirements for continuous monitoring?

Code of Federal Regulations, 2010 CFR

2010-07-01

... continuous monitoring? 60.1805 Section 60.1805 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY..., 1999 Model Rule-Other Monitoring Requirements § 60.1805 Must I meet other requirements for continuous... device. (c) Carbon feed rate if activated carbon is used to control dioxins/furans or mercury emissions. ...

40 CFR 60.1805 - Must I meet other requirements for continuous monitoring?

Code of Federal Regulations, 2014 CFR

2014-07-01

... continuous monitoring? 60.1805 Section 60.1805 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY..., 1999 Model Rule-Other Monitoring Requirements § 60.1805 Must I meet other requirements for continuous... device. (c) Carbon feed rate if activated carbon is used to control dioxins/furans or mercury emissions. ...

40 CFR 60.1805 - Must I meet other requirements for continuous monitoring?

Code of Federal Regulations, 2012 CFR

2012-07-01

... continuous monitoring? 60.1805 Section 60.1805 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY..., 1999 Model Rule-Other Monitoring Requirements § 60.1805 Must I meet other requirements for continuous... device. (c) Carbon feed rate if activated carbon is used to control dioxins/furans or mercury emissions. ...

40 CFR 60.1805 - Must I meet other requirements for continuous monitoring?

Code of Federal Regulations, 2013 CFR

2013-07-01

... continuous monitoring? 60.1805 Section 60.1805 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY..., 1999 Model Rule-Other Monitoring Requirements § 60.1805 Must I meet other requirements for continuous... device. (c) Carbon feed rate if activated carbon is used to control dioxins/furans or mercury emissions. ...

40 CFR 60.1805 - Must I meet other requirements for continuous monitoring?

Code of Federal Regulations, 2011 CFR

2011-07-01

... continuous monitoring? 60.1805 Section 60.1805 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY..., 1999 Model Rule-Other Monitoring Requirements § 60.1805 Must I meet other requirements for continuous... device. (c) Carbon feed rate if activated carbon is used to control dioxins/furans or mercury emissions. ...

OBSERVATIONS ON THE EFFECT OF PROCESS PARAMETERS ON DIOXIN/FURAN YIELD IN MUNICIPAL WASTE AND COAL SYSTEMS

EPA Science Inventory

Effects of fly ash loading; ash-borne, extractable organics; sulfur dioxide (SO2) and hydrogen chloride concentration; and combustion quality on the formation of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) were evaluated in pilot scale tests simu...

Production of xylitol by a Coniochaeta ligniaria strain tolerant of inhibitors and defective in xylose metabolism

USDA-ARS?s Scientific Manuscript database

In conversion of biomass to fuels or chemicals, inhibitory compounds arising from physical-chemical pretreatment of the feedstock can interfere with fermentation of the sugars to product. Fungal strain Coniochaeta ligniaria NRRL30616, metabolizes the furan aldehydes furfural and 5-hydroxymethylfurfu...

Biological abatement of inhibitors in rice hull hydrolyzate and fermentation to ethanol using conventional and engineered microbes

USDA-ARS?s Scientific Manuscript database

Microbial inhibitors arise from lignin, hemicellulose, and degraded sugar during pretreatment of lignocellulosic biomass. The fungus Coniochaeta ligniaria NRRL30616 has native ability to metabolize a number of these compounds, including furan and aromatic aldehydes known to act as inhibitors toward...

Kinetic mechanism of an aldehyde reductase of Saccharomyces cerevisiae that relieves toxicity of furfural and 5-hydroxymethylfurfural

USDA-ARS?s Scientific Manuscript database

An effective means of relieving the toxicity of furan aldehydes, furfural (FFA) and 5-hydroxymethylfurfural (HMF), on fermenting organisms is essential for achieving efficient fermentation of lignocellulosic biomass to ethanol and other products. Ari1p, an aldehyde reductase from Saccharomyces cerev...

40 CFR 60.2720 - May I conduct performance testing less often?

Code of Federal Regulations, 2011 CFR

2011-07-01

... pollutant. For cadmium and lead, both cadmium and lead must be emitted at emission levels no greater than their respective emission levels specified in paragraph (a)(3)(i) of this section for you to qualify for..., carbon monoxide, nitrogen oxides, sulfur dioxide, cadmium, lead, and dioxins/furans, the emission level...

Antiprion activity of DB772 and related monothiophene-and furan-based analogs in a persistently infected ovine microglia culture system

USDA-ARS?s Scientific Manuscript database

The transmissible spongiform encephalopathies are fatal neurodegenerative disorders characterized by the misfolding of the native cellular prion protein (PrP-C) into the accumulating, disease-associated isoform (PrP-Sc). Despite extensive research into the inhibition of prion accumulation, no effect...

INVESTIGATION OF THE POTENTIAL RELEASE OF POLYCHLORINATED DIOXINS AND FURANS FROM PCP-TREATED UTILITY POLES

EPA Science Inventory

The United States (US) Environmental Protection Agency (EPA) estimated that the use of technical grade pentachlorophenol (PCP) between 1970 and 1995 to treat wood was approximately 400,000 metric tons in the US, and that between 4,800 and 36,000 grams of 2,3,7,8-tetrachlorodiben...

40 CFR 60.53b - Standards for municipal waste combustor operating practices.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Circulating fluidized bed combustor 100 4 Pulverized coal/refuse-derived fuel mixed fuel-fired combustor 150 4 Spreader stoker coal/refuse-derived fuel mixed fuel-fired combustor 150 24 a Measured at the combustor... activated carbon injection rate during dioxin/furan or mercury testing. [60 FR 65419, Dec. 19, 1995, as...

40 CFR 60.1285 - What types of stack tests must I conduct?

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 6 2010-07-01 2010-07-01 false What types of stack tests must I... Modification or Reconstruction is Commenced After June 6, 2001 Stack Testing § 60.1285 What types of stack.../furans, cadmium, lead, mercury, particulate matter, opacity, hydrogen chloride, and fugitive ash. ...

40 CFR 60.1285 - What types of stack tests must I conduct?

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 6 2011-07-01 2011-07-01 false What types of stack tests must I... Modification or Reconstruction is Commenced After June 6, 2001 Stack Testing § 60.1285 What types of stack.../furans, cadmium, lead, mercury, particulate matter, opacity, hydrogen chloride, and fugitive ash. ...

Investigation of Resin Systems for Improved Ablative Materials

DTIC Science & Technology

1966-04-01

condensed rings, Boron linear chain of rings Carboranes B-P Resins Polymers Containing Si-O Silicon Si -C Si -N Furan Derivatives Furfural Base Furfural ...8217 Adsorption Theory of Adhesion’ presented at the 144th American Chemical Society Meeting, held in Los Angeles, April 1963. 15. Freeman, J. H. , L. W

A PILOT-SCALE STUDY OF THE PRECURSORS LEADING TO THE FORMATION OF MIXED BROMO-CHLORO DIOXINS AND FURANS

EPA Science Inventory

The paper gives results of experiments in a pilot-scale rotary kiln incinerator simulator where a mixture of chlorinated and brominated surrogate waste was burned in the presence of injected fly-ash from a coal-fired utility boiler. Measurements were made of semivolatile products...

FORMATION OF CHLORINATED DIOXINS AND FURANS IN A HAZARDOUS-WASTE-FIRING INDUSTRIAL BOILER

EPA Science Inventory

This research examined the potential for emissions of polychlorinated diebnzodioxin and dibenzofuran (PCDD/F) from industrial boilers that cofire hazardous waste. PCDD/F emissions were sampled from a 732 kW (2.5 x 106 Btu/h), 3-pass, firetube boiler using #2 fuel oil cofired wit...

A STUDY OF THE MASS BALANCE OF DIOXINS AND FURANS IN LACTATING COWS IN BACKGROUND CONDITIONS

EPA Science Inventory

Consumption of animal fats account for as much as 95% of the human background exposure to compounds with dioxin-like activity. Although it is generally believed that most domestic meat and dairy animals receive most of their exposure from their feed, there is limited data availa...

Data Validation Standard Operating Procedure for EPA Method 1613 Revision B, Tetra-through Octa-chlorinated Dioxins and Furans by Isotope Dillution (High Resolution Gas Chromatography/High Resolution Mass Spectrometry)

EPA Pesticide Factsheets

Method used for isomer specific determination todetect the Tetra- through octa- chlorinated dibenzo-p-dioxins and dibenzofurans associatedwith the CWA, RCRA, Comprehensive Environmental Response, Compensation and Liability Act and the SDWA

40 CFR 60.1410 - What must I include in my annual report?

Code of Federal Regulations, 2014 CFR

2014-07-01

...? 60.1410 Section 60.1410 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... Modification or Reconstruction is Commenced After June 6, 2001 Reporting § 60.1410 What must I include in my... units, for eight pollutants, as recorded under § 60.1360(a): (1) Dioxins/furans. (2) Cadmium. (3) Lead...

40 CFR 62.15330 - What must I include in the initial report?

Code of Federal Regulations, 2014 CFR

2014-07-01

... emissions. (3) The 4-hour block or 24-hour daily arithmetic average concentration of carbon monoxide... specifications in appendix B of 40 CFR part 60 in conducting the evaluation. (e) The maximum demonstrated load of... combustion unit uses activated carbon to control dioxins/furans or mercury emissions, the average carbon feed...

40 CFR 60.1410 - What must I include in my annual report?

Code of Federal Regulations, 2012 CFR

2012-07-01

...? 60.1410 Section 60.1410 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... Modification or Reconstruction is Commenced After June 6, 2001 Reporting § 60.1410 What must I include in my... units, for eight pollutants, as recorded under § 60.1360(a): (1) Dioxins/furans. (2) Cadmium. (3) Lead...

40 CFR 60.1410 - What must I include in my annual report?

Code of Federal Regulations, 2013 CFR

2013-07-01

...? 60.1410 Section 60.1410 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... Modification or Reconstruction is Commenced After June 6, 2001 Reporting § 60.1410 What must I include in my... units, for eight pollutants, as recorded under § 60.1360(a): (1) Dioxins/furans. (2) Cadmium. (3) Lead...

40 CFR Table 3 to Subpart X of... - Toxic Equivalency Factors

Code of Federal Regulations, 2012 CFR

2012-07-01

... Subpart X of Part 63 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS... Standards For Hazardous Air Pollutants From Secondary Lead Smelting Pt. 63, Subpt. X, Table 3 Table 3 to Subpart X of Part 63—Toxic Equivalency Factors Dioxin/furan congener Toxic equivalency factor 2,3,7,8...

40 CFR Table 3 to Subpart X of... - Toxic Equivalency Factors

Code of Federal Regulations, 2013 CFR

2013-07-01

... Subpart X of Part 63 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS... Standards For Hazardous Air Pollutants From Secondary Lead Smelting Pt. 63, Subpt. X, Table 3 Table 3 to Subpart X of Part 63—Toxic Equivalency Factors Dioxin/furan congener Toxic equivalency factor 2,3,7,8...

40 CFR Table 3 to Subpart X of... - Toxic Equivalency Factors

Code of Federal Regulations, 2014 CFR

2014-07-01

... Subpart X of Part 63 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS... Standards For Hazardous Air Pollutants From Secondary Lead Smelting Pt. 63, Subpt. X, Table 3 Table 3 to Subpart X of Part 63—Toxic Equivalency Factors Dioxin/furan congener Toxicequivalency factor 2,3,7,8...

A MIXTURE OF DIOXINS, FURANS, AND NON-ORTHO PCBS BASED UPON CONCENSUS TOXIC EQUIVLENCY FACTORS PRODUCES DIOXIN-LIKE REPRODUCTIVE EFFECTS

EPA Science Inventory

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD; dioxin) and related polyhalogenated aromatic hydrocarbons (PHAHs) alter the reproductive development of laboratory animals. Therefore, we exposed animals to a mixture of dioxin and dioxin-like compounds including TCDD, 1,2,3,7,8-pentachl...

Phthalic anhydride production from hemicellulose solutions: Technoeconomic analysis and life cycle assessment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lin, Zhaojia; Ierapetritou, Marianthi; Nikolakis, Vladimiros

2015-07-14

The process synthesis, technoeconomic analysis, and life cycle assessment (LCA) of a novel route for phthalic anhydride (PAN) production from hemicellulose solutions are presented. The production contains six steps including dehydration of xylose to furfural, reductive decarbonylation of furfural to furan, oxidation of furfural to maleic anhydride (MA), Diels-Alder cycloaddition of furan, and MA to exo-4,10-dioxa-tricyclo[5.2.1.0]dec-8-ene-3,5-dione followed by dehydration to PAN in the presence of mixture of methanesulfonic acid and acetic anhydride (AAN) which is converted to acetyl methanesulfonate and acetic acid (AAD), and dehydration of AAD to AAN. The minimum selling price of PAN is determined to be $810/metricmore » ton about half of oil-based PAN. The coproduction of high-value products is essential to improve the economics. Biomass feedstock contributes to the majority of cost. LCA results shows that biomass-based PAN has advantages over oil-based PAN to reduce climate change and fossil depletion however requires more water usage.« less

Development of Remendable Polymer Composites using a Thermoreversible Reaction

NASA Astrophysics Data System (ADS)

Peterson, Amy Michelle

2011-12-01

Materials that can repair cracks and recover from mechanical failure are desirable. Because remendable materials both repair and prevent the propagation of cracks on the micro scale, they offer the potential for increased durability, safety, and cost efficiency for many applications. The focus of this work was to understand the kinetic and physical parameters that control thermoreversible Diels-Alder bond formation in different types of healable polymeric systems. Three healing systems were developed based on the thermoreversible Diets-Alder reaction of furan and maleimide. In one, crack healing of a thermoset was induced by thermally reversible cross-linking of a secondary phase. In another, a furan-functionalized epoxy-amine thermoset were healed with a bismaleimide solution at room temperature and minimal pressure, with significant load recovery possible multiple times. The third system allowed for interfacial healing of glass fiber-reinforced epoxy-amine composites via compatible functionalization of glass fibers and the polymer network. The Diels-Alder reaction was characterized in all systems as well as highly mobile small molecule solutions. It was found that mobility, coupled with kinetics, dictate the extent of reaction and consequent strength recovery.

Identification of furan fatty acids in the lipids of common carp (Cyprinus carpio L.).

PubMed

Chvalová, Daniela; Špička, Jiří

2016-06-01

Fatty acid (FA) composition was analyzed in muscle and gonad tissues of marketed common carp (Cyprinus carpio). The extracted lipids were separated into four fractions: polar lipids (PL), diacylglycerols, free fatty acids and triacylglycerols (TAG) using thin layer chromatography. FA content within the lipid fractions was determined by gas chromatography with flame ionization detector (GC/FID). The muscle lipids consisted primarily of TAG (96.9% of total FA), while PL were the major component of both male (67.6%) and female gonad (58.6%) lipids. Polyunsaturated fatty acids predominated in PL of all tissues (52.2-55.8% of total FA); monounsaturated fatty acids were the most abundant FA group in TAG of muscle (51.8%) and female gonads (47.8%) whereas high proportion of furan fatty acids (F-acids) (38.2%) was detected in TAG of male gonads. Eight F-acids were identified by gas chromatography-mass spectrometry (GC/MS) in male gonad samples, including less common 12,15-epoxy-13,14-dimethylnonadeca-12,14-dienoic acid with even-numbered alkyl moiety. Copyright © 2016 Elsevier Ltd. All rights reserved.

Optimization of furfural and 5-hydroxymethylfurfural production from wheat straw by a microwave-assisted process.

PubMed

Yemiş, Oktay; Mazza, Giuseppe

2012-04-01

Optimization of acid-catalyzed conversion conditions of wheat straw into furfural, 5-hydroxymethylfurfural (HMF), glucose, and xylose was studied by response surface methodology (RSM). A central composite design (CCD) was used to determine the effects of independent variables, including reaction temperature (140-200 °C), residence time (1-41 min), pH (0.1-2.1), and liquid:solid ratio (15-195 mL/g) on furan and sugar production. The surface response analysis revealed that temperature, time and pH had a strong influence on the furfural, HMF, xylose and glucose yield, whereas liquid to solid ratio was found not to be significant. The initial pH of solution was the most important variable in acid-catalyzed conversion of wheat straw to furans. The maximum predicted furfural, HMF, xylose and glucose yields were 66%, 3.4%, 100%, and 65%, respectively. This study demonstrated that the microwave-assisted process was a very effective method for the xylose production from wheat straw by diluted acid catalysis. Crown Copyright © 2012. Published by Elsevier Ltd. All rights reserved.

Mechanism of Microwave-Assisted Pyrolysis of Glucose to Furfural Revealed by Isotopic Tracer and Quantum Chemical Calculations.

PubMed

Bao, Liwei; Shi, Lei; Luo, Hu; Kong, Lingzhao; Li, Shenggang; Wei, Wei; Sun, Yuhan

2017-08-10

Glucose labeled with 13 C or 18 O was used to investigate the mechanism of its conversion into furfural by microwaveassisted pyrolysis. The isotopic content and location in furfural were determined from GC-MS and 13 C NMR spectroscopic measurements and data analysis. The results suggest that the carbon skeleton in furfural is mainly derived from C1 to C5 of glucose, whereas the C of the aldehyde group and the O of the furan ring in furfural primarily originate from C1 and O5 of glucose, respectively. For the first time, the source of O in the furan ring of furfural was elucidated directly by experiment, providing results that are consistent with predictions from recent quantum chemical calculations. Moreover, further theoretical calculations indicate substantially lower energy barriers than previous predictions by considering the potential catalytic effect of formic acid, which is one of the pyrolysis products. The catalytic role of formic acid is further confirmed by experimental evidence. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Biodegradable hyaluronic acid hydrogels to control release of dexamethasone through aqueous Diels-Alder chemistry for adipose tissue engineering.

PubMed

Fan, Ming; Ma, Ye; Zhang, Ziwei; Mao, Jiahui; Tan, Huaping; Hu, Xiaohong

2015-11-01

A robust synthetic strategy of biopolymer-based hydrogels has been developed where hyaluronic acid derivatives reacted through aqueous Diels-Alder chemistry without the involvement of chemical catalysts, allowing for control and sustain release of dexamethasone. To conjugate the hydrogel, furan and maleimide functionalized hyaluronic acid were synthesized, respectively, as well as furan functionalized dexamethasone, for the covalent immobilization. Chemical structure, gelation time, morphologies, swelling kinetics, weight loss, compressive modulus and dexamethasone release of the hydrogel system in PBS at 37°C were studied. The results demonstrated that the aqueous Diels-Alder chemistry provides an extremely selective reaction and proceeds with high efficiency for hydrogel conjugation and covalent immobilization of dexamethasone. Cell culture results showed that the dexamethasone immobilized hydrogel was noncytotoxic and preserved proliferation of entrapped human adipose-derived stem cells. This synthetic approach uniquely allows for the direct fabrication of biologically functionalized gel scaffolds with ideal structures for adipose tissue engineering, which provides a competitive alternative to conventional conjugation techniques such as copper mediated click chemistry. Copyright © 2015. Published by Elsevier B.V.

Phthalic anhydride production from hemicellulose solutions: Technoeconomic analysis and life cycle assessment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lin, Zhaojia; Ierapetritou, Marianthi; Nikolakis, Vladimiros

The process synthesis, technoeconomic analysis, and life cycle assessment (LCA) of a novel route for phthalic anhydride (PAN) production from hemicellulose solutions are presented. The production contains six steps including dehydration of xylose to furfural, reductive decarbonylation of furfural to furan, oxidation of furfural to maleic anhydride (MA), Diels-Alder cycloaddition of furan, and MA to exo-4,10-dioxa-tricyclo[5.2.1.0]dec-8-ene-3,5-dione followed by dehydration to PAN in the presence of mixture of methanesulfonic acid and acetic anhydride (AAN) which is converted to acetyl methanesulfonate and acetic acid (AAD), and dehydration of AAD to AAN. The minimum selling price of PAN is determined to be $810/metricmore » ton about half of oil-based PAN. The coproduction of high-value products is essential to improve the economics. Biomass feedstock contributes to the majority of cost. LCA results shows that biomass-based PAN has advantages over oil-based PAN to reduce climate change and fossil depletion however requires more water usage.« less

Biotransformation of furfural and 5-hydroxymethyl furfural (HMF) by Clostridium acetobutylicum ATCC 824 during butanol fermentation.

PubMed

Zhang, Yan; Han, Bei; Ezeji, Thaddeus Chukwuemeka

2012-02-15

The ability of fermenting microorganisms to tolerate furan aldehyde inhibitors (furfural and 5-hydroxymethyl furfural (HMF)) will enhance efficient bioconversion of lignocellulosic biomass hydrolysates to fuels and chemicals. The effect of furfural and HMF on butanol production by Clostridium acetobutylicum 824 was investigated. Whereas specific growth rates, μ, of C. acetobutylicum in the presence of furfural and HMF were in the range of 15-85% and 23-78%, respectively, of the uninhibited Control, μ increased by 8-15% and 23-38% following exhaustion of furfural and HMF in the bioreactor. Using high performance liquid chromatography and spectrophotometric assays, batch fermentations revealed that furfural and HMF were converted to furfuryl alcohol and 2,5-bis-hydroxymethylfuran, respectively, with specific conversion rates of 2.13g furfural and 0.50g HMF per g (biomass) per hour, by exponentially growing C. acetobutylicum. Biotransformation of these furans to lesser inhibitory compounds by C. acetobutylicum will probably enhance overall fermentation of lignocellulosic hydrolysates to butanol. Copyright © 2011 Elsevier B.V. All rights reserved.

Emissions from open burning of simulated military waste from forward operating bases.

PubMed

Aurell, Johanna; Gullett, Brian K; Yamamoto, Dirk

2012-10-16

Emissions from open burning of simulated military waste from forward operating bases (FOBs) were extensively characterized as an initial step in assessing potential inhalation exposure of FOB personnel and future disposal alternatives. Emissions from two different burning scenarios, so-called "burn piles/pits" and an air curtain burner/"burn box", were compared using simulated FOB waste from municipal and commercial sources. A comprehensive array of emissions was quantified, including CO(2), PM(2.5), volatile organic compounds (VOCs), polyaromatic hydrocarbons (PAHs), polychlorinated dibenzodioxins and -furans (PCDDs/PCDFs), polybrominated dibenzodioxins and -furans (PBDDs/PBDFs), and metals. In general, smoldering conditions in the burn box and the burn pile led to similar emissions. However, when the burn box underwent periodic waste charging to maintain sustained combustion, PM(2.5), VOCs, and PAH emissions dropped considerably compared to smoldering conditions and the overall burn pile results. The PCDD/PCDF and PBDD/PBDF emission factors for the burn piles were 50 times higher than those from the burn box likely due to the dominance of smoldering combustion in the burn piles.

Synthesis and antimalarial activity study of some new Mannich bases of 7-chloro-4-aminoquinoline.

PubMed

Roy, Susanta; Chetia, Dipak; Rudrapal, Mithun; Prakash, Anil

2013-05-01

New derivatives of 7-chloro-4-aminoquinoline Mannich base were prepared by selectively modifying the aliphatic diethyl amino function of isoquine with different aliphatic/aromatic heterocyclic primary amino moieties at Mannich side chain. The synthesized compounds were characterized by their analytical and spectral data, and screened for in-vitro antimalarial activity against a chloroquine-sensitive 3D7 strain of Plasmodium falciparum. All the compounds showed in-vitro antimalarial activity at the tested dose; which, however, was considerably less than that of the standard reference drug, chloroquine. Among synthesized compounds, compounds with cyclohexyl (2f), methyl (2c) substitutions showed better activity than compounds substituted with n-octyl (2a), propyl (2b), 3-aminopropyl (2d) and furan-2- ylmethyl (2e) moieties at aminomethyl side chain. The results clearly demonstrate that the compound substituted with saturated cycloalkyl moiety (cyclohexyl) exhibited to some extent increased activity as compared to the compound containing heterocyclic moiety (furan-2-ylmethyl), and compounds with short chain alkyl substitutions (methyl, propyl) were found to be more active than that of compounds with long chain alkyl substitution (n-octyl).

Chemical Conversion Pathways and Kinetic Modeling for the OH-Initiated Reaction of Triclosan in Gas-Phase

PubMed Central

Zhang, Xue; Zhang, Chenxi; Sun, Xiaomin; Kang, Lingyan; Zhao, Yan

2015-01-01

As a widely used antimicrobial additive in daily consumption, attention has been paid to the degradation and conversion of triclosan for a long time. The quantum chemistry calculation and the canonical variational transition state theory are employed to investigate the mechanism and kinetic property. Besides addition and abstraction, oxidation pathways and further conversion pathways are also considered. The OH radicals could degrade triclosan to phenols, aldehydes, and other easily degradable substances. The conversion mechanisms of triclosan to the polychlorinated dibenzopdioxin and furan (PCDD/Fs) and polychlorinated biphenyls (PCBs) are clearly illustrated and the toxicity would be strengthened in such pathways. Single radical and diradical pathways are compared to study the conversion mechanism of dichlorodibenzo dioxin (DCDD). Furthermore, thermochemistry is discussed in detail. Kinetic property is calculated and the consequent ratio of kadd/ktotal and kabs/ktotal at 298.15 K are 0.955 and 0.045, respectively. Thus, the OH radical addition reactions are predominant, the substitute position of OH radical on triclosan is very important to generate PCDD and furan, and biradical is also a vital intermediate to produce dioxin. PMID:25867482

Improving hydrocarbon yield from catalytic fast co-pyrolysis of hemicellulose and plastic in the dual-catalyst bed of CaO and HZSM-5.

PubMed

Ding, Kuan; Zhong, Zhaoping; Wang, Jia; Zhang, Bo; Fan, Liangliang; Liu, Shiyu; Wang, Yunpu; Liu, Yuhuan; Zhong, Daoxu; Chen, Paul; Ruan, Roger

2018-08-01

The high concentration of oxygenated compounds in pyrolytic products prohibits the conversion of hemicellulose to important biofuels and chemicals via fast pyrolysis. Herein a dual-catalyst bed of CaO and HZSM-5 was developed to convert acids in the pyrolytic products of xylan to valuable hydrocarbons. Meanwhile, LLDPE was co-pyrolyzed with xylan to supplement hydrogen during the catalysis of HZSM-5. The results showed that CaO could effectively transform acids into ketones. A minimum yield of acids (2.74%) and a maximum yield of ketones (42.93%) were obtained at a catalyst to feedstock ratio of 2:1. The dual-catalyst bed dramatically increased the yield of aromatics. Moreover, hydrogen-rich fragments derived from LLDPE promoted the Diels-Alder reactions of furans and participated in the hydrocarbon pool reactions of non-furanic compounds. As a result, a higher yield of hydrocarbons was achieved. This study provides a fundamental for recovering energy and chemicals from pyrolysis of hemicellulose. Copyright © 2018 Elsevier Ltd. All rights reserved.

High-pressure thermal sterilization: food safety and food quality of baby food puree.

PubMed

Sevenich, Robert; Kleinstueck, Elke; Crews, Colin; Anderson, Warwick; Pye, Celine; Riddellova, Katerina; Hradecky, Jaromir; Moravcova, Eliska; Reineke, Kai; Knorr, Dietrich

2014-02-01

The benefits that high-pressure thermal sterilization offers as an emerging technology could be used to produce a better overall food quality. Due to shorter dwell times and lower thermal load applied to the product in comparison to the thermal retorting, lower numbers and quantities of unwanted food processing contaminants (FPCs), for example, furan, acrylamide, HMF, and MCPD-esters could be formed. Two spore strains were used to test the technique; Geobacillus stearothermophilus and Bacillus amyloliquefaciens, over the temperature range 90 to 121 °C at 600 MPa. The treatments were carried out in baby food puree and ACES-buffer. The treatments at 90 and 105 °C showed that G. stearothermophilus is more pressure-sensitive than B. amyloliquefaciens. The formation of FPCs was monitored during the sterilization process and compared to the amounts found in retorted samples of the same food. The amounts of furan could be reduced between 81% to 96% in comparison to retorting for the tested temperature pressure combination even at sterilization conditions of F₀-value in 7 min. © 2014 Institute of Food Technologists®

Opioid Receptor Probes Derived from Cycloaddition of the Hallucinogen Natural Product Salvinorin A†

PubMed Central

Lozama, Anthony; Cunningham, Christopher W.; Caspers, Michael J.; Douglas, Justin T.; Dersch, Christina M.; Rothman, Richard B.; Prisinzano, Thomas E.

2011-01-01

As part of our continuing efforts toward more fully understanding the structure-activity relationships of the neoclerodane diterpene salvinorin A, we report the synthesis and biological characterization of unique cycloadducts through [4+2] Diels-Alder cycloaddition. Microwave-assisted methods were developed and successfully employed, aiding in functionalizing the chemically sensitive salvinorin A scaffold. This demonstrates the first reported results for both cycloaddition of the furan ring and functionalization via microwave-assisted methodology of the salvinorin A skeleton. The cycloadducts yielded herein introduce electron-withdrawing substituents and bulky aromatic groups into the C-12 position. Kappa opioid (KOP) receptor space was explored through aromatization of the bent oxanorbornadiene system possessed by the cycloadducts to a planar phenyl ring system. Although dimethyl- and diethylcarboxylate analogues 5 and 6 retain some affinity and selectivity for KOP receptors and are full agonists, their aromatized counterparts 13 and 14 have reduced affinity for KOP receptors. The methods developed herein signify a novel approach toward rapidly probing the structure-activity relationships of furan containing natural products. PMID:21338114

Zinc Chloride Influence on The Resins Furan Polymerization to Foundry Moulds

NASA Astrophysics Data System (ADS)

de Miranda, Leila Figueiredo; Vale, Marcus; Júnior, Antonio Hortêncio Munhoz; Masson, Terezinha Jocelen; de Andrade e Silva, Leonardo Gondin

The resins used in foundry molds developed for the automotive market has led to major changes in the manufacturing method of foundry molds. The polymerization of these resins and a subsequent curing are used to connect to the foundry sand in a rigid structure capable of receiving and holding liquid metal. It is essential to know the process of polymerization of these resins and their impact on the final properties of the obtained molds, especially in the mechanical characteristics. In this work it was studied the influence of the addition of zinc chloride (in solution) in the sand-furan resin mixture, with the aim of reducing the relation between the extraction time intervals and time bench life. The results showed that addition of percentages of the order of 5.0wt% to 7.5wt% zinc chloride solution reduces this ratio between 10% and 17%; this means that the casting model may be extracted from the sand mass in a smaller time interval increasing the productivity of manufacturing molds. It was also observed that there was also an increase of 9% to 18% in bench life intervals.

Isolation of a dihydrobenzofuran lignan from South American dragon's blood (Croton spp.) as an inhibitor of cell proliferation.

PubMed

Pieters, L; de Bruyne, T; Claeys, M; Vlietinck, A; Calomme, M; vanden Berghe, D

1993-06-01

Dragon's blood is a red viscous latex extracted from the cortex of various Croton spp. (Euphorbiaceae), most commonly Croton lechleri, Croton draconoides (or Croton palanostigma), and Croton erythrochilus. It is used in South American popular medicine for several purposes, including wound healing. Bioassay-guided fractionation of dragon's blood, using an in vitro test system for the stimulation of human umbilical vein endothelial cells, has resulted in the isolation of a dihydrobenzofuran lignan, 3',4-O-dimethylcedrusin or 4-O-methyldihydrodehydrodiconiferyl alcohol [2-(3',4'-dimethoxyphenyl)-3-hydroxymethyl-2,3-dihydro-7-methoxybenzo furan-5- propan-1-ol] [1] as the biologically active principle. A related compound, 4-O-methylcedrusin [2-(3',4'-dimethoxyphenyl)-3-hydroxymethyl-2,3-dihydro-7-hydroxybenzo furan-5- propan-1-ol] [2], and the alkaloid taspine [3], also isolated from dragon's blood, were not active in the same assay. A cell proliferation assay, measuring the incorporation of tritiated thymidine in endothelial cells, showed that compound 1 did not stimulate cell proliferation, but rather inhibited thymidine incorporation, while protecting cells against degradation in a starvation medium.

Estimation of dioxin and furan elimination rates with a pharmacokinetic model.

PubMed

Van der Molen, G W; Kooijman, B A; Wittsiepe, J; Schrey, P; Flesch-Janys, D; Slob, W

2000-01-01

Quantitative description of the pharmacokinetics of dioxins and furans in humans can be of great help for the assessment of health risks posed by these compounds. To that the elimination rates of sixteen 2,3,7,8-chlorinated dibenzodioxins and dibenzofurans are estimated from both a longitudinal and a cross-sectional data set using the model of Van der Molen et al. [Van der Molen G.W., Kooijman S.A.L.M., and Slob W. A generic toxicokinetic model for persistent lipophilic compounds in humans: an application to TCDD. Fundam Appl Toxicol 1996: 31: 83-94]. In this model the elimination rate is given by the (constant) specific elimination rate multiplied with the ratio between the lipid weight of the liver and total body lipid weight. Body composition, body weight and intake are assumed to depend on age. The elimination rate is, therefore, not constant. For 49-year-old males, the elimination rate estimates range between 0.03 per year for 1,2,3,6,7,8-hexaCDF to 1.0 per year for octaCDF. The elimination rates of the most toxic congeners, 2,3,7,8-tetraCDD, 1,2,3,7,8-pentaCDD, and 2,3,4,7,8-pentaCDF, were estimated at 0.09, 0.06, and 0.07, respectively, based on the cross-sectional data, and 0.11, 0.09, and 0.09 based on the longitudinal data. The elimination rates of dioxins decrease with age between 0.0011 per year for 1,2,3,6,7,8-hexaCDD and 0.0035 per year for 1,2,3,4,6,7,8-heptaCDD. For furans the average decrease is 0.0033 per year. The elimination rates were estimated both from a longitudinal and a cross-sectional data set, and agreed quite well with each other, after taking account of historical changes in average intake levels.

A survey of chemical constituents in National Fish Hatchery fish feed

USGS Publications Warehouse

Maule, Alec G.; Gannam, Ann; Davis, Jay

2006-01-01

Recent studies have demonstrated that various fish feeds contain significant concentrations of contaminants, many of which can bioaccumulate and bioconcentrate in fish. It appears that numerous organochlorine (OC) contaminants are present in the fish oils and fish meals used in feed manufacture, and some researchers speculate that all fish feeds contain measurable levels of some contaminants. To determine the presence and concentration of contaminants in feeds used in National Fish Hatcheries managed by the U.S. Fish & Wildlife Service, we systematically collected samples of feed from 11 hatcheries that raise cold-water species, and analyzed them for a suite of chemical contaminants. All of the samples (collected from October 2001 to October 2003) contained measurable concentrations of at least one dioxin, furan, polychlorinated biphenyl (PCB) congener, or dichlorodiphenyltrichloroethane (DDT) metabolite. All samples which were assayed for all contaminants contained one or more of those classes of compounds and most contained more than one; dioxin was detected in 39 of the 55 samples for which it was assayed, 24 of 55 contained furans and 24 of 55 samples contained DDT or its metabolites. There with 10- to 150-fold differences in the range in concentrations of the additive totals for PCBs, dioxins, furans and DDT. Although PCBs were the most commonly detected contaminant in our study (all samples in which it was assayed), the concentrations (range: 0.07 to 10.46 ng g·1 wet weight) were low compared to those reported previously. In general, we also found lower levels of organochlorine contaminants than have been reported previously in fish feed. Perhaps most notable is the near absence of OC pesticides~xcept for DDT (and its metabolites) and just two samples containing benzene hexachloride (Lindane). While contaminant concentrations were generally low, the ecological impacts can not be determined without a measure of the bioaccumulation of these compounds in the fish and the fate of these compounds after the fish are released from the hatcheries.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zeng, Xiaofei; Borole, Abhijeet P.; Pavlostathis, Spyros G.

Furanic and phenolic compounds are 20 lignocellulose-derived compounds known to inhibit to H2- and ethanol- producing microorganisms in dark fermentation. Bioelectrochemical conversion of furanic and phenolic compounds to electricity or H2 has recently been demonstrated as a productive method to use these compounds. However, potential inhibitory effect of furanic and phenolic compounds on exoelectrogenesis in bioelectrochemical systems is not well understood. This study systematically investigated the inhibitory effect of furfural (FF), 5-hydroxymethylfurfural (HMF), syringic acid (SA), vanillic acid (VA), and 4-hydroxybenzoic acid (HBA) on exoelectrogenesis in the bioanode of a microbial electrolysis cell. A mixture of these five compounds atmore » an increasing initial total concentration from 0.8 to 8.0 g/L resulted in current decrease up to 91%. The observed inhibition primarily affected exoelectrogenesis, instead of non-exoelectrogenic biotransformation pathways (e.g., fermentation) of the five compounds. Furthermore, the parent compounds at a high concentration, as opposed to their biotransformation products, were responsible for the observed inhibition. Tests with individual compounds show that all five parent compounds contributed to the observed inhibition by the mixture. The IC50 (concentration resulting in 50% current decrease) was estimated as 2.7 g/L for FF, 3.0 g/L for HMF, 1.9 g/L for SA, 2.1 g/L for VA and 2.0 g/L for HBA. Nevertheless, these compounds below their non-inhibitory concentrations jointly resulted in significant inhibition as a mixture. Catechol and phenol, which were persistent biotransformation products of the mixture, inhibited exoelectrogens at high concentrations, but to a lesser extent than the parent compounds. Recovery of exoelectrogenesis from inhibition by all compounds was observed, except for catechol, which resulted in irreversible inhibition. The reversibility of inhibition, as well as the observed difference in recovery rates, suggest different modes of exoelectrogenesis inhibition, related to the hydrophobicity of the inhibiting compounds.« less

Biotransformation of furanic and phenolic compounds with hydrogen gas production in a microbial electrolysis cell

DOE PAGES

Zeng, Xiaofei; Borole, Abhijeet P.; Pavlostathis, Spyros G.

2015-10-27

In this study, furanic and phenolic compounds are problematic byproducts resulting from the decomposition of lignocellulosic biomass during biofuel production. This study assessed the capacity of a microbial electrolysis cell (MEC) to produce hydrogen gas (H 2) using a mixture of two furanic (furfural, FF; 5-hydroxymethyl furfural, HMF) and three phenolic (syringic acid, SA; vanillic acid, VA; and 4-hydroxybenzoic acid, HBA) compounds as the sole carbon and energy source in the bioanode. The rate and extent of biotransformation of the five compounds, efficiency of H 2 production, as well as the anode microbial community structure were investigated. The five compoundsmore » were completely transformed within 7-day batch runs and their biotransformation rate increased with increasing initial concentration. At an initial concentration of 1,200 mg/L (8.7 mM) of the mixture of the five compounds, their biotransformation rate ranged from 0.85 to 2.34 mM/d. The anode coulombic efficiency was 44-69%, which is comparable to wastewater-fed MECs. The H 2 yield varied from 0.26 to 0.42 g H 2-COD/g COD removed in the anode, and the bioanode volume-normalized H 2 production rate was 0.07-0.1 L/L-d. The major identified fermentation products that did not transform further were catechol and phenol. Acetate was the direct substrate for exoelectrogenesis. Current and H 2 production were inhibited at an initial substrate concentration of 1,200 mg/L, resulting in acetate accumulation at a much higher level than that measured in other batch runs conducted with a lower initial concentration of the five compounds. The anode microbial community consisted of exoelectrogens, putative degraders of the five compounds, and syntrophic partners of exoelectrogens. The H 2 production route demonstrated in this study has proven to be an alternative to the currently used process of reforming natural gas to supply H 2 needed to upgrade bio-oils to stable hydrocarbon fuels.« less

Biotransformation of Furanic and Phenolic Compounds with Hydrogen Gas Production in a Microbial Electrolysis Cell.

PubMed

Zeng, Xiaofei; Borole, Abhijeet P; Pavlostathis, Spyros G

2015-11-17

Furanic and phenolic compounds are problematic byproducts resulting from the breakdown of lignocellulosic biomass during biofuel production. The capacity of a microbial electrolysis cell (MEC) to produce hydrogen gas (H2) using a mixture of two furanic (furfural, FF; 5-hydroxymethyl furfural, HMF) and three phenolic (syringic acid, SA; vanillic acid, VA; and 4-hydroxybenzoic acid, HBA) compounds as the substrate in the bioanode was assessed. The rate and extent of biotransformation of the five compounds and efficiency of H2 production, as well as the structure of the anode microbial community, were investigated. The five compounds were completely transformed within 7-day batch runs and their biotransformation rate increased with increasing initial concentration. At an initial concentration of 1200 mg/L (8.7 mM) of the mixture of the five compounds, their biotransformation rate ranged from 0.85 to 2.34 mM/d. The anode Coulombic efficiency was 44-69%, which is comparable to that of wastewater-fed MECs. The H2 yield varied from 0.26 to 0.42 g H2-COD/g COD removed in the anode, and the bioanode volume-normalized H2 production rate was 0.07-0.1 L/L-d. The biotransformation of the five compounds took place via fermentation followed by exoelectrogenesis. The major identified fermentation products that did not transform further were catechol and phenol. Acetate was the direct substrate for exoelectrogenesis. Current and H2 production were inhibited at an initial substrate concentration of 1200 mg/L, resulting in acetate accumulation at a much higher level than that measured in other batch runs conducted with a lower initial concentration of the five compounds. The anode microbial community consisted of exoelectrogens, putative degraders of the five compounds, and syntrophic partners of exoelectrogens. The MEC H2 production demonstrated in this study is an alternative to the currently used process of reforming natural gas to supply H2 needed to upgrade bio-oils to stable hydrocarbon fuels.

Pathway and Surface Mechanism Studies of 1,3-butadiene Selective Oxidation Over Vanadium-Molybdenum-Oxygen Catalysts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schroeder, William David

2001-01-01

The partial oxidation of 1,3-butadiene has been investigated over VMoO catalysts synthesized by sol-gel techniques. Surface areas were 9-14 m 2/g, and compositions were within the solid solution regime, i.e. below 15.0 mol % MoO 3/(MoO 3 + V 2O 5). Laser Raman Spectroscopy and XRD data indicated that solid solutions were formed, and pre- and post-reaction XPS data indicated that catalyst surfaces contained some V +4 and were further reduced in 1,3-butadiene oxidation. A reaction pathway for 1,3-butadiene partial oxidation to maleic anhydride was shown to involve intermediates such as 3,4-epoxy-1-butene, crotonaldehyde, furan, and 2-butene-1,4-dial. The addition of watermore » to the reaction stream substantially increased catalyst activity and improved selectivity to crotonaldehyde and furan at specific reaction temperatures. At higher water addition concentrations, furan selectivity increased from 12% to over 25%. The catalytic effects of water addition were related to competitive adsorption with various V 2O 5-based surface sites, including the vanadyl V=O, corner sharing V-O-V and edge sharing V-O oxygen. Higher levels of water addition were proposed to impose acidic character by dissociative adsorption. In addition, a novel combinatorial synthesis technique for VMoO was used to investigate the phase transitions of V 2O 5, solid solutions of Mo in V 2O 5, V 9Mo 6O 40, and other reduced VMoO compounds, characterized by laser Raman spectroscopy. The natural composition gradient imposed by the sputter deposition apparatus was used to create VMoO arrays containing 225 samples ranging from 7.0-42 mol% MoO 3/(V 2O 5 + MoO 3), determined by EDS analysis.« less

Draft genome sequence of Coniochaeta ligniaria NRRL 30616, a lignocellulolytic fungus for bioabatement of inhibitors in plant biomass hydrolysates

USDA-ARS?s Scientific Manuscript database

Here, we report the first draft genome sequence (42.38 Mb that contains 13,657 genes) of Coniochaeta ligniaria NRRL30616, an ascomycete with high biotechnological relevance in the bioenergy field given its high potential for bioabatement of toxic furanic compounds in plant biomass hydrolysates and i...

Pre-treatment step with Leuconostoc mesenteroides or L. pseudomesenteroides strains removes furfural from Zymomonas mobilis ethanolic fermentation broth

USDA-ARS?s Scientific Manuscript database

Furfural (furan-2-carboxaldehyde), formed during dilute acid hydrolysis of biomass, is an inhibitor of growth and ethanol production by Zymomonas mobilis. The present study used a biological pre-treatment to reduce that amount of furfural in a model biofuel fermentation broth. The pre-treatment in...

Annulation of β-naphthols and 4-hydroxycoumarins with vinylsulfonium salts: synthesis of dihydrofuran derivatives.

PubMed

Chen, Zi-Cong; Tong, Lang; Du, Zhi-Bo; Mao, Zhi-Feng; Zhang, Xue-Jing; Zou, Yong; Yan, Ming

2018-04-18

A new synthetic approach to dihydrofuran derivatives via the annulation reaction of β-naphthols and 4-hydroxycoumarins with vinylsulfonium salts has been developed. A variety of dihydrofuran derivatives were prepared in moderate to good yields under mild conditions. The products could be readily transformed to the corresponding furans via the dehydrogenation with DDQ.

Background Contamination by Coplanar Polychlorinated Biphenyls (PCBS) in Trace Level High Resolution Gas Chromatography/High Resolution Mass Spectrometry (HRGC/HRMS) Analytical Procedures

EPA Science Inventory

The addition of the "dioxin-like" polychlorinated biphenyl (PCB) congeners to the assessment of risk associated with the 2,3,7,8-chlorine substituted dioxins and furans has dramatically increased the number of laboratories worldwide that are developing analytical procedures for t...

Assessment of PCDD/F and PBDD/F Emissions from Coal-fired Power Plants during Injection of Brominated Activated Carbon for Mercury Control

EPA Science Inventory

The effect of the injection of brominated powdered activated carbon (Br-PAC) on the emission of brominated and chlorinated dioxins and furans in coal combustion flue gas has been evaluated. The tests were performed at two U.S. Department of Energy (DOE) demonstration sites where ...

Passive Sampling Provides Evidence for Neward Bay as a Source of Polychlorinated Dibenzo-p-Dioxins and Furans to the New York/New Jersey, USA, Atmosphere

EPA Science Inventory

Freely dissolved and gas phase polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) were measured in the water column and atmosphere at five locations within Newark Bay (New Jersey, USA) from May 2008 to August 2009 with polyethylene (PE) passive ...

INSIGHTS FROM AHR AND ARNT GENE KNOCKOUT STUDIES REGARDING RESPONSES TO TCDD AND REGULATION OF NORMAL EMBRYONIC DEVELOPMENT

EPA Science Inventory

The aryl hydrocarbon receptor (AhR) and the AhR nuclear translocator (ARNT) are members of the Per-ARNT-Sim (PAS) family of proteins. The AhR binds members of the chemical family that includes dioxins, furans and coplanar polychlorinated biphenyls (PCBs). A ligand-AhR-ARNT comp...

Dioxin, furan, PCB, and PBDE levels in U.S. foods: Survey trends and consumer exposure

USDA-ARS?s Scientific Manuscript database

The U.S. Department of Agriculture, Agricultural Research Service (USDA-ARS) and Food Safety and Inspection Service (USDA-FSIS) have conducted statistical surveys for dioxins (PCDDs, PCDFs, and PCBs) and polybrominated diphenyl ethers every 5 years since the mid-1990s (mid-1990s, 2002-3, 2007-8). I...

Unexpected Catalytic Reactions of Silyl-protected Enoldiazoacetates With Nitrile Oxides That Form 5- Arylaminofuran-2(3H)-one-4-carboxylates

PubMed Central

Xu, Xinfang; Shabashov, Dmitry; Zavalij, Peter Y.; Doyle, Michael P.

2012-01-01

Silyl-protected enoldiazoacetates undergo dirhodium(II) catalyzed reactions with nitrile oxides to form acid-labile ketenimines via dipolar cycloaddition of nitrile oxides to a donor/acceptor cyclopropene and Lossen rearrangement of the dipolar adduct; acid catalysis converts the ketenimine to the furan product. PMID:22272728

40 CFR 60.1775 - What types of stack tests must I conduct?

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 6 2011-07-01 2011-07-01 false What types of stack tests must I...-Stack Testing § 60.1775 What types of stack tests must I conduct? Conduct initial and annual stack tests to measure the emission levels of dioxins/furans, cadmium, lead, mercury, particulate matter, opacity...

40 CFR 60.1775 - What types of stack tests must I conduct?

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 6 2010-07-01 2010-07-01 false What types of stack tests must I...-Stack Testing § 60.1775 What types of stack tests must I conduct? Conduct initial and annual stack tests to measure the emission levels of dioxins/furans, cadmium, lead, mercury, particulate matter, opacity...

Role of potassium exchange in catalytic pyrolysis of biomass over ZSM-5: Formation of alkyl phenols and furans

USDA-ARS?s Scientific Manuscript database

Catalytic fast pyrolysis of biomass with ZSM-5 type zeolites is a commonly considered in situ upgrading technique for the production of partially deoxygenated bio-oils. The acidity and structure of ZSM-5 catalysts favor the production of aromatic hydrocarbons from oxygenates present in the pyrolysis...

Understanding decay resistance, dimensional stability and strength changes in heat treated and acetylated wood

Treesearch

Roger M. Rowell; Rebecca E. Ibach; James McSweeny; Thomas Nilsson

2009-01-01

Reductions in hygroscopicity, increased dimensional stability and decay resistance of heat-treated wood depend on decomposition of a large portion of the hemicelluloses in the wood cell wall. In theory, these hemicelluloses are converted to small organic molecules, water and volatile furan-type intermediates that can polymerize in the cell wall. Reductions in...

Using low temperature to balance enzymatic saccharification and furan formation during SPORL pretreatment of Douglas-fir

Treesearch

C. Zhang; C.J. Houtman; J.Y. Zhu

2014-01-01

tComparing analytical results for Sulfite Pretreatment to Overcome the Recalcitrance of Lignocelluloses(SPORL) of Douglas-fir (Pseudotsuga menziesii) at two different temperatures shows that the apparentactivation energy of sugar degradation is higher than that of hemicellulose hydrolysis, approximately161 kJ/mole versus 100 kJ/mole. Thus, one can...

A Computational Experiment of the Endo versus Exo Preference in a Diels-Alder Reaction

ERIC Educational Resources Information Center

Rowley, Christopher N.; Woo, Tom K.

2009-01-01

We have developed and tested a computational laboratory that investigates an endo versus exo Diels-Alder cycloaddition. This laboratory employed density functional theory (DFT) calculations to study the cycloaddition of N-phenylmaleimide to furan. The endo and exo stereoisomers of the product were distinguished by building the two isomers in a…

Chlorinated Dioxins and Furans from Kelp and Copper Sulfate: Initial Investigations of Dioxin Formation in Mineral Feed Supplements (Journal Article)

EPA Science Inventory

In 2002, dioxins were discovered in animal feed ingredients during a random sampling by Irish officials and subsequently traced to particular mineral supplements produced at a Minnesota plant in the United States. These products sold under the names of SQM Mineral Products and C...

77 FR 58315 - Hazardous Waste Management System; Identification and Listing of Hazardous Waste; Final Exclusion

Federal Register 2010, 2011, 2012, 2013, 2014

2012-09-20

... E (Phosphorus), and 1613B (Dioxins and Furans). The laboratory Quality Assurance Plan (Attachment 2... fine sand layer that underlies the North Landfarm but overlies a clay liner. Within said sand layer are... Quality Objectives are to demonstrate that samples of the ExxonMobil North Landfarm underflow water are...

DIBENZO-P-DIOXINS IN THE ENVIRONMENT FROM CERAMICS AND POTTERY PRODUCED FROM BALL CLAY MINED IN THE U.S.

EPA Science Inventory

Processed ball clay samples used in the production of ceramics and samples of the ceramic products were collected and analyzed for the presence and concentration of the 2,3,7,8-Cl substituted polychlorinated dibenzo-p-dioxins and furans (PCDDs/PCDFs). The processed ball clay had...

One-pot conversion of biomass-derived xylose and furfural into levulinate esters via acid catalysis.

PubMed

Hu, Xun; Jiang, Shengjuan; Wu, Liping; Wang, Shuai; Li, Chun-Zhu

2017-03-07

Direct conversion of biomass-derived xylose and furfural into levulinic acid, a platform molecule, via acid-catalysis has been accomplished for the first time in dimethoxymethane/methanol. Dimethoxymethane acted as an electrophile to transform furfural into 5-hydroxymethylfurfural (HMF). Methanol suppressed both the polymerisation of the sugars/furans and the Aldol condensation of levulinic acid/ester.

Unexpected catalytic reactions of silyl-protected enol diazoacetates with nitrile oxides that form 5-arylaminofuran-2(3H)-one-4-carboxylates.

PubMed

Xu, Xinfang; Shabashov, Dmitry; Zavalij, Peter Y; Doyle, Michael P

2012-02-03

Silyl-protected enol diazoacetates undergo dirhodium(II)-catalyzed reactions with nitrile oxides to form acid-labile ketenimines via dipolar cycloaddition of nitrile oxides to a donor/acceptor cyclopropene and Lossen rearrangement of the dipolar adduct; acid catalysis converts the ketenimine to the furan product. © 2012 American Chemical Society

40 CFR Table 2 to Subpart Dddd of... - Model Rule-Emission Limitations

Code of Federal Regulations, 2010 CFR

2010-07-01

... meter 3-run average (1 hour minimum sample time per run) Performance test (Method 29 of appendix A of this part) Carbon monoxide 157 parts per million by dry volume 3-run average (1 hour minimum sample time per run) Performance test (Method 10, 10A, or 10B, of appendix A of this part) Dioxins/furans...

Differential sensitivity of polyhydroxyalkanoate producing bacteria to fermentation inhibitors and comparison of polyhydroxybutyrate production from Burkholderia cepacia and Pseudomonas pseudoflava

Treesearch

Diane Dietrich; Barbara Illman; Casey Crooks

2013-01-01

The aim of this study is determine the relative sensitivity of a panel of seven polyhydroxyalkanoate producing bacteria to a panel of seven lignocellulosic-derived fermentation inhibitors representing aliphatic acids, furans and phenolics. A further aim was to measure the polyhydroxybutyrate production of select organisms on lignocellulosic-derived monosaccharides...

The furan microsolvation blind challenge for quantum chemical methods: First steps

NASA Astrophysics Data System (ADS)

Gottschalk, Hannes C.; Poblotzki, Anja; Suhm, Martin A.; Al-Mogren, Muneerah M.; Antony, Jens; Auer, Alexander A.; Baptista, Leonardo; Benoit, David M.; Bistoni, Giovanni; Bohle, Fabian; Dahmani, Rahma; Firaha, Dzmitry; Grimme, Stefan; Hansen, Andreas; Harding, Michael E.; Hochlaf, Majdi; Holzer, Christof; Jansen, Georg; Klopper, Wim; Kopp, Wassja A.; Kröger, Leif C.; Leonhard, Kai; Mouhib, Halima; Neese, Frank; Pereira, Max N.; Ulusoy, Inga S.; Wuttke, Axel; Mata, Ricardo A.

2018-01-01

Herein we present the results of a blind challenge to quantum chemical methods in the calculation of dimerization preferences in the low temperature gas phase. The target of study was the first step of the microsolvation of furan, 2-methylfuran and 2,5-dimethylfuran with methanol. The dimers were investigated through IR spectroscopy of a supersonic jet expansion. From the measured bands, it was possible to identify a persistent hydrogen bonding OH-O motif in the predominant species. From the presence of another band, which can be attributed to an OH-π interaction, we were able to assert that the energy gap between the two types of dimers should be less than or close to 1 kJ/mol across the series. These values served as a first evaluation ruler for the 12 entries featured in the challenge. A tentative stricter evaluation of the challenge results is also carried out, combining theoretical and experimental results in order to define a smaller error bar. The process was carried out in a double-blind fashion, with both theory and experimental groups unaware of the results on the other side, with the exception of the 2,5-dimethylfuran system which was featured in an earlier publication.

C–H arylation of unsubstituted furan and thiophene with acceptor bromides: access to donor–acceptor–donor-type building blocks for organic electronics.

PubMed

Matsidik, Rukiya; Martin, Johannes; Schmidt, Simon; Obermayer, Johannes; Lombeck, Florian; Nübling, Fritz; Komber, Hartmut; Fazzi, Daniele; Sommer, Michael

2015-01-16

Pd-catalyzed direct arylation (DA) reaction conditions have been established for unsubstituted furan (Fu) and thiophene (Th) with three popular acceptor building blocks to be used in materials for organic electronics, namely 4,7-dibromo-2,1,3-benzothiadiazole (BTBr2), N,N′-dialkylated 2,6-dibromonaphthalene-1,4,5,8-bis(dicarboximide) (NDIBr2), and 1,4-dibromotetrafluorobenzene (F4Br2). Reactions with BTBr2, F4Br2, and NDIBr2 require different solvents to obtain high yields. The use of dimethylacetamide (DMAc) is essential for the successful coupling of BTBr2 and F4Br2, but detrimental for NDIBr2, as the electron-deficient NDI core is prone to nucleophilic core substitution in DMAc as solvent but not in toluene. NDIFu2 is much more planar compared to NDITh2, resulting in an enhanced charge-transfer character, which makes it an interesting building block for conjugated systems designed for organic electronics. This study highlights direct arylation as a simple and inexpensive method to construct a series of important donor–acceptor–donor building blocks to be further used for the preparation of a variety of conjugated materials.

Dioxin analysis by gas chromatography-Fourier transform ion cyclotron resonance mass spectrometry (GC-FTICRMS).

PubMed

Taguchi, Vince Y; Nieckarz, Robert J; Clement, Ray E; Krolik, Stefan; Williams, Robert

2010-11-01

The feasibility of utilizing a gas chromatograph-tandem quadrupole-Fourier transform ion cyclotron resonance mass spectrometer (GC-MS/MS-FTICRMS) to analyze chlorinated-dioxins/furans (CDDs/CDFs) and mixed halogenated dioxins/furans (HDDs/HDFs) was investigated by operating the system in the GC-FTICRMS mode. CDDs/CDFs and mixed HDDs/HDFs could be analyzed at 50,000 to 100,000 resolving power (RP) on the capillary gas chromatographic time scale. Initial experiments demonstrated that 1 pg of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and 5 pg of 2-bromo-3,7,8-trichlorodibenzo-p-dioxin (BTrCDD) could be detected. The feasibility of utilizing an FTICRMS for screening of CDDs/CDFs, HDDs/HDFs and related compounds was also investigated by analyzing an extract from vegetation exposed to fall-out from an industrial fire. CDDs/CDFs, chlorinated pyrenes and chlorinated tetracenes could be detected from a Kendrick plot analysis of the ultrahigh resolution mass spectra. Mass accuracies were of the order of 0.5 ppm on standards with external mass calibration and 1 ppm on a sample with internal mass calibration. Copyright © 2010 American Society for Mass Spectrometry. Published by Elsevier Inc. All rights reserved.

Photoionization of furan from the ground and excited electronic states.

PubMed

Ponzi, Aurora; Sapunar, Marin; Angeli, Celestino; Cimiraglia, Renzo; Došlić, Nađa; Decleva, Piero

2016-02-28

Here we present a comparative computational study of the photoionization of furan from the ground and the two lowest-lying excited electronic states. The study aims to assess the quality of the computational methods currently employed for treating bound and continuum states in photoionization. For the ionization from the ground electronic state, we show that the Dyson orbital approach combined with an accurate solution of the continuum one particle wave functions in a multicenter B-spline basis, at the density functional theory (DFT) level, provides cross sections and asymmetry parameters in excellent agreement with experimental data. On the contrary, when the Dyson orbitals approach is combined with the Coulomb and orthogonalized Coulomb treatments of the continuum, the results are qualitatively different. In excited electronic states, three electronic structure methods, TDDFT, ADC(2), and CASSCF, have been used for the computation of the Dyson orbitals, while the continuum was treated at the B-spline/DFT level. We show that photoionization observables are sensitive probes of the nature of the excited states as well as of the quality of excited state wave functions. This paves the way for applications in more complex situations such as time resolved photoionization spectroscopy.

Crystal structure of an unknown tetra­hydro­furan solvate of tetra­kis­(μ 3-cyanato-κ3 N:N:N)tetra­kis­[(triphenyl­phosphane-κP)­silver(I)

PubMed Central

Frenzel, Peter; Schaarschmidt, Dieter; Jakob, Alexander; Lang, Heinrich

2015-01-01

In the title compound, [{[(C6H5)3P]Ag}4{NCO}4], a distorted Ag4N4-heterocubane core is set up by four AgI ions being coordinated by the N atoms of the cyanato anions in a μ 3-bridging mode. In addition, a tri­phenyl­phosphine ligand is datively bonded to each of the AgI ions. Intra­molecular Ag⋯Ag distances as short as 3.133 (9) Å suggest the presence of argentophilic (d 10⋯d 10) inter­actions. Five moderate-to-weak C—H⋯O hydrogen-bonding inter­actions are observed in the crystal structure, spanning a three-dimensional network. A region of electron density was treated with the SQUEEZE procedure in PLATON [Spek (2015). Acta Cryst. C71, 9–18] following unsuccessful attempts to model it as being part of disordered tetra­hydro­furan solvent mol­ecules. The given chemical formula and other crystal data do not take into account these solvent mol­ecules. PMID:26594421

Co(II) and Cd(II) Complexes Derived from Heterocyclic Schiff-Bases: Synthesis, Structural Characterisation, and Biological Activity

PubMed Central

Ahmed, Riyadh M.; Yousif, Enaam I.; Al-Jeboori, Mohamad J.

2013-01-01

New monomeric cobalt and cadmium complexes with Schiff-bases, namely, N′-[(E)-(3-hydroxy-4-methoxyphenyl)methylidene]furan-2-carbohydrazide (L1) and N′-[(E)-(3-hydroxy-4-methoxyphenyl)methylidene]thiophene-2-carbohydrazide (L2) are reported. Schiff-base ligands L1 and L2 were derived from condensation of 3-hydroxy-4-methoxybenzaldehyde (iso-vanillin) with furan-2-carboxylic acid hydrazide and thiophene-2-carboxylic acid hydrazide, respectively. Complexes of the general formula [M(L)2]Cl2 (where M = Co(II) or Cd(II), L = L1 or L2) have been obtained from the reaction of the corresponding metal chloride with the ligands. The ligands and their metal complexes were characterised by spectroscopic methods (FTIR, UV-Vis, 1H, and 13C NMR spectra), elemental analysis, metal content, magnetic measurement, and conductance. These studies revealed the formation of four-coordinate complexes in which the geometry about metal ion is tetrahedral. Biological activity of the ligands and their metal complexes against gram positive bacterial strain Bacillus (G+) and gram negative bacteria Pseudomonas (G−) revealed that the metal complexes become less resistive to the microbial activities as compared to the free ligands. PMID:24027449

Magnetic hyaluronic acid nanospheres via aqueous Diels-Alder chemistry to deliver dexamethasone for adipose tissue engineering.

PubMed

Jia, Yang; Fan, Ming; Chen, Huinan; Miao, Yuting; Xing, Lian; Jiang, Bohong; Cheng, Qifan; Liu, Dongwei; Bao, Weikang; Qian, Bin; Wang, Jionglu; Xing, Xiaodong; Tan, Huaping; Ling, Zhonghua; Chen, Yong

2015-11-15

Biopolymer-based nanospheres have great potential in the field of drug delivery and tissue regenerative medicine. In this work, we present a flexible way to conjugate a magnetic hyaluronic acid (HA) nanosphere system that are capable of vectoring delivery of adipogenic factor, e.g. dexamethasone, for adipose tissue engineering. Conjugation of nanospheres was established by aqueous Diels-Alder chemistry between furan and maleimide of HA derivatives. Simultaneously, a furan functionalized dexamethasone peptide, GQPGK, was synthesized and covalently immobilized into the nanospheres. The magnetic HA nanospheres were fabricated by encapsulating super-paramagnetic iron oxide nanoparticles, which exhibited quick magnetic sensitivity. The aqueous Diels-Alder chemistry made nanospheres high binding efficiency of dexamethasone, and the vectoring delivery of dexamethasone could be easily controlled by a external magnetic field. The potential application of the magnetic HA nanospheres on vectoring delivery of adipogenic factor was confirmed by co-culture of human adipose-derived stem cells (ASCs). In vitro cytotoxicity tests demonstrated that incorporation of dexamethasone into magnetic HA nanospheres showed high efficiency to promote ASCs viabilities, in particular under a magnetic field, which suggested a promising future for adipose regeneration applications. Copyright © 2015 Elsevier Inc. All rights reserved.

Liquid-Phase Catalytic Transfer Hydrogenation of Furfural over Homogeneous Lewis Acid-Ru/C Catalysts.

PubMed

Panagiotopoulou, Paraskevi; Martin, Nickolas; Vlachos, Dionisios G

2015-06-22

The catalytic performance of homogeneous Lewis acid catalysts and their interaction with Ru/C catalyst are studied in the catalytic transfer hydrogenation of furfural by using 2-propanol as a solvent and hydrogen donor. We find that Lewis acid catalysts hydrogenate the furfural to furfuryl alcohol, which is then etherified with 2-propanol. The catalytic activity is correlated with an empirical scale of Lewis acid strength and exhibits a volcano behavior. Lanthanides are the most active, with DyCl3 giving complete furfural conversion and a 97 % yield of furfuryl alcohol at 180 °C after 3 h. The combination of Lewis acid and Ru/C catalysts results in synergy for the stronger Lewis acid catalysts, with a significant increase in the furfural conversion and methyl furan yield. Optimum results are obtained by using Ru/C combined with VCl3 , AlCl3 , SnCl4 , YbCl3 , and RuCl3 . Our results indicate that the combination of Lewis acid/metal catalysts is a general strategy for performing tandem reactions in the upgrade of furans. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Phosphoric acid based pretreatment of switchgrass and fermentation of entire slurry to ethanol using a simplified process.

PubMed

Wu, Wei; Rondon, Vanessa; Weeks, Kalvin; Pullammanappallil, Pratap; Ingram, Lonnie O; Shanmugam, K T

2018-03-01

Switchgrass (Alamo) was pretreated with phosphoric acid (0.75 and 1%, w/w) at three temperatures (160, 175 and 190 °C) and time (5, 7.5 and 10 min) using a steam gun. The slurry after pretreatment was liquefied by enzymes and the released sugars were fermented in a simultaneous saccharification and co-fermentation process to ethanol using ethanologenic Escherichia coli strain SL100. Among the three variables in pretreatment, temperature and time were critical in supporting ethanol titer and yield. Enzyme hydrolysis significantly increased the concentration of furans in slurries, apparently due to release of furans bound to the solids. The highest ethanol titer of 21.2 ± 0.3 g/L ethanol obtained at the pretreatment condition of 190-1-7.5 (temperature-acid concentration-time) and 10% solids loading accounted for 190 ± 2.9 g ethanol/kg of raw switch grass. This converts to 61.7 gallons of ethanol per ton of dry switchgrass, a value that is comparable to other published pretreatment conditions. Copyright © 2017 Elsevier Ltd. All rights reserved.

Biotransformation of 5-hydroxy-methylfurfural into 2,5-furan-dicarboxylic acid by bacterial isolate using thermal acid algal hydrolysate.

PubMed

Yang, Chu-Fang; Huang, Ci-Ruei

2016-08-01

Thermal acid hydrolysis is often used to deal with lignocellulosic biomasses, but 5-hydroxy-methylfurfural (5-HMF) formed during hydrolysis deeply influences downstream fermentation. 2,5-Furan-dicarboxylic acid (FDCA), which is in the list of future important biomass platform molecules can be obtained using 5-HMF biotransformation. Based on the connection between 5-HMF removal in acid hydrolysate and FDCA production, the optimum thermal acid hydrolysis condition for macroalgae Chaetomorpha linum was established. Potential microbes capable of transforming 5-HMF into FDCA were isolated and characterized under various parameters and inoculated into algal hydrolysate to perform 5-HMF biotransformation. The optimum hydrolysis condition was to apply 0.5M HCl to treat 3% algal biomass under 121°C for 15min. Isolated Burkholderia cepacia H-2 could transform 2000mg/L 5-HMF at the initial pH of 7 at 28°C and 1276mg/L FDCA was received. Strain B. cepacia H-2 was suitable for treating the algal hydrolysate without dilution, receiving 989.5mg/L FDCA. Copyright © 2016 Elsevier Ltd. All rights reserved.

A new reaction pathway other than the Criegee mechanism for the ozonolysis of a cyclic unsaturated ether

NASA Astrophysics Data System (ADS)

Tang, Shanshan; Du, Lin; Tsona, Narcisse T.; Zhao, Hailiang; Wang, Wenxing

2017-08-01

Biofuels are considered to be an environmental friendly alternative to fossil fuels. Furanic compounds have been considered as second generation biofuels as they can be produced from non-food biomass. However, the atmospheric behavior of such compounds is required to evaluate their potential to be used as biofuels. The matrix isolation technique combined with infrared spectroscopy has been used to study the ozonolysis mechanism of 2,5-dihydrofuran. A new reaction pathway that is different from the widely accepted Criegee mechanism has been found. Experimental and theoretical results show the evidence of the formation of a furan-H2O3 complex through a dehydrogenation process. The complex is trapped in the argon matrix and stabilized through hydrogen bonding interaction. Meanwhile, the conventional ozonolysis intermediates were also observed, including the primary ozonide, the Criegee intermediate and the secondary ozonide. The present study highlights the cases in which the Criegee mechanism is not the dominant pathway for the reactions of cyclic alkenes with ozone. The cyclic alkenes that can form an aromatic conjugated system by the dehydrogenation process may follow the new mechanism when react with ozone in the atmosphere.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kang, Beom-Goo; Pramanik, Nabendu B.; Singha, Nikhil K.

The anionic block copolymerization of 4,4' -vinylphenyl-N,N-bis(4-tert-butylphenyl)benzenamine (A) with furfuryl isocyanate (B) was carried out using potassium naphthalenide (K-Naph) in tetrahydrofuran at -78 and -98 °C to prepare well-defined block copolymers containing furan groups for the formation of thermoreversible networks via a Diels Alder (DA) reaction. While no block copolymerization was observed in the absence of sodium tetraphenylborate (NaBPh 4) due to side reactions, well-defined poly-(B-b-A-b-B) (PBAB) copolymers with controlled molecular weights (M n = 18 700 19 500 g mol -1) and narrow molecular weight distributions (M w/M n = 1.08 -1.17) were successfully synthesized in the presence ofmore » excess NaBPh 4. We prevented the occurrence of the undesirable side reactions during polymerization of B of NaBPh 4, which results in the change in the countercation from K + to Na + for further polymerization of B. Moreover, the cross-linking via the DA reaction between the furan groups of PBAB and bismaleimide was proved by FT-IR and differential scanning calorimetry (DSC), and the thermoreversible properties of the cross-linked polymer were subsequently investigated using DSC and solubility testing.« less

Demethylation of 5,n-di-tert-butyl-8,n-dimethoxy[2.n]metacyclophane-1-ynes with BBr3 to afford novel [n]benzofuranophanes

NASA Astrophysics Data System (ADS)

Akther, Thamina; Islam, Md Monarul; Matsumoto, Taisuke; Tanaka, Junji; Feng, Xing; Redshaw, Carl; Yamato, Takehiko

2016-10-01

Novel [n]benzofuranophanes (n = 8 & 10) 2a-b have been prepared by successive intramolecular cyclization from 5,19-di-tert-butyl-8,22-dimethoxy[n]metacyclophane-1-yne (syn-1a-b) by treatment with BBr3 in CH2Cl2 at room temperature for 8h. [2.n]Benzofuranophanes 2a-b were also obtained by treatment of 1,2-di-endo-bromo-5,19-di-tert-butyl-8,22-dimethoxy[n]metacyclophane (meso-3a-b) with BBr3 in CH2Cl2 by using the same reaction conditions. 1H NMR spectra of 2a-b reveals the formation of intramolecular hydrogen bonding between hydroxyl proton with the oxygen of the furan moiety and X-ray analysis shows that the lengths between H (OH) and O (furan) are 1.981 and 1.823 Å̊, respectively. The conformation of [8]benzofuranophane 2a in solution is rigid with restricted rotation around the diaryl linkage rather than [10]benzofuranophane 2b because of weak intramolecular hydrogen bonding and the short length of the cross-linking chain.

Chemical conversion pathways and kinetic modeling for the OH-initiated reaction of triclosan in gas-phase.

PubMed

Zhang, Xue; Zhang, Chenxi; Sun, Xiaomin; Kang, Lingyan; Zhao, Yan

2015-04-10

As a widely used antimicrobial additive in daily consumption, attention has been paid to the degradation and conversion of triclosan for a long time. The quantum chemistry calculation and the canonical variational transition state theory are employed to investigate the mechanism and kinetic property. Besides addition and abstraction, oxidation pathways and further conversion pathways are also considered. The OH radicals could degrade triclosan to phenols, aldehydes, and other easily degradable substances. The conversion mechanisms of triclosan to the polychlorinated dibenzopdioxin and furan (PCDD/Fs) and polychlorinated biphenyls (PCBs) are clearly illustrated and the toxicity would be strengthened in such pathways. Single radical and diradical pathways are compared to study the conversion mechanism of dichlorodibenzo dioxin (DCDD). Furthermore, thermochemistry is discussed in detail. Kinetic property is calculated and the consequent ratio of k add/k total and k abs/k total at 298.15 K are 0.955 and 0.045, respectively. Thus, the OH radical addition reactions are predominant, the substitute position of OH radical on triclosan is very important to generate PCDD and furan, and biradical is also a vital intermediate to produce dioxin.

Co-combustion of E+E waste plastics in the TAMARA test plant

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vehlow, J.; Wanke, T.; Bergfeldt, B.

1997-12-01

The co-combustion of different amounts of various plastic fractions of electrical and electronic (E+E) waste together with municipal solid waste has been tested in the Karlsruhe test incinerator TAMARA. The tests revealed no negative influences upon the combustion process. In general the increased heating value of the fuel causes an improved burnout in all residue streams. The halogens Cl and Br added with the plastics are mainly transferred as HCl or HBr into the flue gas. An influence upon the formation of chlorinated dioxins and furans could not be observed. With increasing Br feed bromine containing homologues were detected inmore » the raw gas. The furans formed easier than the dioxins and those homologues carrying one Br atom were by far prevailing. Even at high Br input the total amount of mixed halogenated species was limited to approximately 30% of the total load of such compounds which did not leave the typical operation window for PCDD/PCDF in TAMARA. The co-combustion tests demonstrated that MSW combustion is an ecologically acceptable and economically sound disposal route for limited amounts of specific E+E waste.« less

Impact of forest fires on the concentrations of polychlorinated dibenzo-p-dioxin and dibenzofurans in coastal waters of central Chile.

PubMed

Salamanca, Marco; Chandía, Cristian; Hernández, Aldo

2016-12-15

The relationship between the occurrence of forest fires in central Chile and the total concentration of dioxins and furans (PCDD/F) in nearby coastal waters was analyzed. The data for this analysis was obtained from a long-term environmental monitoring program (PROMNA) in the Bio-Bio Region. Quantification of PCDD/F was performed using HRGC/HRMS at the MSS laboratory in England. Between 2006 and 2014, peaks were observed in February 2007 and 2012. These concentration maxima coincided with major forest fires in the Bio-Bio Region and particularly with those in the Itata River Basin. The January 2012 fires generated an intense short-term response that was associated with atmospheric transport which increases medium toxicity furan-type congeners concentrations (TCDF, PCDF and HxCDF) and six months later a concentration increase of low toxicity dioxin-type congeners was observed (OCDD, HpCDD and HxCDD) coinciding with maximum winter river flow. These results suggest that forest fires near the coastal zone are responsible for increases in PCDD/F concentration observed in the study area. Copyright © 2016 Elsevier B.V. All rights reserved.

Crystal structure of bis-[tetra-kis-(tetra-hydro-furan-κO)lithium] bis[μ-2,2',2''-methanetriyltris(4,6-di-tert-butylphenolato)-κ4O,O':O',O'']-dimagnesiate.

PubMed

Zhou, Hongyan; Wang, Lei

2017-07-01

The title ion-association metal complex, [Li(C 4 H 8 O) 4 ] 2 [Mg 2 (C 43 H 61 O 3 ) 2 ], has been synthesized from the tridentate phenolic ligand tris-(3,5-di- tert -butyl-2-hy-droxy-phen-yl)methane in tetra-hydro-furan (THF). The aryl-oxo magnesiate complex anion is binuclear with each Mg 2 O 4 complex unit inversion-related and bridged through the two tridentate chelating phenolate O-donors of the ligand. The complex centres have a distorted tetra-hedral stereochemistry [Mg-O range 1.8796 (17)-2.0005 (16) Å] and an Mg⋯Mg separation of 2.9430 (14) Å]. The LiO 4 coodination sphere of the cation comprises four THF O-donor atoms and has a slightly distorted tetra-hedral conformation [Li-O range 1.899 (5)- 1.953 (5) Å]. In the crystal, a number of stabilizing intra-anion C-H⋯O hydrogen-bonding inter-actions are present but no inter-species associations are found.

Design, structural and spectroscopic elucidation of new nitroaromatic carboxylic acids and semicarbazones for the in vitro screening of anti-leishmanial activity

NASA Astrophysics Data System (ADS)

Dias, L. C.; de Lima, G. M.; Pinheiro, C. B.; Rodrigues, B. L.; Donnici, C. L.; Fujiwara, R. T.; Bartholomeu, D. C.; Ferreira, R. A.; Ferreira, S. R.; Mendes, T. A. O.; da Silva, J. G.; Alves, M. R. A.

2015-01-01

In this paper we report the synthesis and characterization of four new nitroaromatic compounds, 2-{6-nitrobenzo[1,3]dioxol-5-(methyleneamino)}benzoic acid (1), 2-{[5-(2-nitrophenyl)furan-2-yl]methylene-amino}benzoic acid (2), 2-{(6-nitrobenzo[1,3]dioxol-5-yl)methylene}hydrazinecarboxamide (3) and 2-{[5-(2-nitrophenyl)furan-2-yl]methylene}hydrazinecarboxamide (4). Compounds (1)-(4) have been authenticated by infrared and NMR spectroscopy, and the structure of (1), (2) and (4) have been determined by X-ray diffraction. In addition, the in vitro ability of compounds (1)-(4) to inhibit the growth of Leishmania infantum has been evaluated. Comparisons of the redox potential of the compounds and leishmanicidal activity indicate that the presence of the electroactive nitro group is important for the biological activity. The inhibition activity of compound (3) is comparable to that of the reference drug, SbCl3. Considering the important side effects and the low efficiency of SbCl3 in the case of resistance, compound (3) deserves further attention as a promising anti-leishmanicidal drug for veterinary use.

40 CFR Table 2 to Subpart Hhh of... - Toxic Equivalency Factors

Code of Federal Regulations, 2010 CFR

2010-07-01

..., Subpt. HHH, Table 2 Table 2 to Subpart HHH of Part 62—Toxic Equivalency Factors Dioxin/furan congener Toxic equivalency factor 2,3,7,8-tetrachlorinated dibenzo-p-dioxin 1 1,2,3,7,8-pentachlorinated dibenzo-p-dioxin 0.5 1,2,3,4,7,8-hexachlorinated dibenzo-p-dioxin 0.1 1,2,3,7,8,9-hexachlorinated dibenzo-p...

40 CFR Table 2 to Subpart Ttttt of... - Toxic Equivalency Factors

Code of Federal Regulations, 2010 CFR

2010-07-01

..., Subpt. TTTTT, Table 2 Table 2 to Subpart TTTTT of Part 63—Toxic Equivalency Factors Dioxin/furan congener Toxic equivalency factor 2,3,7,8-tetrachlorinated dibenzo-p-dioxin 1 1,2,3,7,8-pentachlorinated dibenzo-p-dioxin 1 1,2,3,4,7,8-hexachlorinated dibenzo-p-dioxin 0.1 1,2,3,7,8,9-hexachlorinated dibenzo-p...

Recycling tires? Reversible crosslinking of poly(butadiene).

PubMed

Trovatti, Eliane; Lacerda, Talita M; Carvalho, Antonio J F; Gandini, Alessandro

2015-04-01

Furan-modified poly(butadiene) prepared by the thiol-ene click reaction is crosslinked with bismaleimides through the Diels-Alder reaction, giving rise to a novel recyclable elastomer. This is possible because of the thermal reversibility of the adducts responsible for the formation of the network. The use of this strategy provides the possibility to produce recyclable tires. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Heat treatment of wet wood fiber: A study of the effect of reaction conditions on the formation of furfurals

Treesearch

Mandla A. Tshabalala; James D. McSweeny; Roger M. Rowell

2012-01-01

Furan monomers are produced when wood is heated at high temperatures. To understand the process conditions for production of furfural (FF) and hydroxymethylfurfural (HMF) from wood, samples of milled aspen wood were subjected to autohydrolyzis by microwave heating in a sealed Teflon reactor. The experiments were designed to simulate temperature and pressure variables...

Lipotoxicity, β cell dysfunction, and gestational diabetes.

PubMed

Nolan, Christopher J

2014-04-01

Gestational diabetes (GDM) is caused by failure of islet β cells to meet the increased insulin requirements of pregnancy. Recently, Prentice et al. (2014) discovered a 7-fold elevation of the furan fatty acid metabolite 3-carboxy-4-methyl-5-propyl-2-furanopropanoic acid (CMPF) in plasma of women with GDM and showed that CMPF directly induces β cell dysfunction. Copyright © 2014 Elsevier Inc. All rights reserved.

40 CFR Appendix - Tables to Subpart DDDDD of Part 63

Code of Federal Regulations, 2012 CFR

2012-07-01

.... Mercury 2.1E-07 lb per MMBtu of heat input 0.2E-06 Collect enough volume to meet an in-stack detection... time, use a span value of 20 ppmv. e. Dioxins/Furans 4 ng/dscm (TEQ) corrected to 7 percent oxygen 9.2E....2E-09 (TEQ) Collect a minimum of 1 dscm per run. 12. Units designed to burn gas 2 (other) gases a...

40 CFR Appendix - Tables to Subpart DDDDD of Part 63

Code of Federal Regulations, 2011 CFR

2011-07-01

.... Mercury 2.1E-07 lb per MMBtu of heat input 0.2E-06 Collect enough volume to meet an in-stack detection... time, use a span value of 20 ppmv. e. Dioxins/Furans 4 ng/dscm (TEQ) corrected to 7 percent oxygen 9.2E....2E-09 (TEQ) Collect a minimum of 1 dscm per run. 12. Units designed to burn gas 2 (other) gases a...

40 CFR Table 1a to Subpart Ec of... - Emissions Limits for Small, Medium, and Large HMIWI at Affected Facilities as Defined in § 60.50c...

Code of Federal Regulations, 2011 CFR

2011-07-01

... limits HMIWI size Small Medium Large Averaging time 1 Methodfor demonstrating compliance 2 Particulate matter Milligrams per dry standard cubic meter (grains per dry standard cubic foot) 69 (0.03) 34 (0.015.../furans (grains per billion dry standard cubic feet) or nanograms per dry standard cubic meter TEQ (grains...

40 CFR Table 1b to Subpart Ec of... - Emissions Limits for Small, Medium, and Large HMIWI at Affected Facilities as Defined in § 60.50c...

Code of Federal Regulations, 2011 CFR

2011-07-01

... HMIWI size Small Medium Large Averaging time 1 Method fordemonstrating compliance 2 Particulate matter Milligrams per dry standard cubic meter (grains per dry standard cubic foot) 66 (0.029) 22 (0.0095) 18 (0.../furans (grains per billion dry standard cubic feet) or nanograms per dry standard cubic meter TEQ (grains...

40 CFR Table 3 to Subpart Cccc of... - Toxic Equivalency Factors

Code of Federal Regulations, 2010 CFR

2010-07-01

... Table 3 to Subpart CCCC of Part 60—Toxic Equivalency Factors Dioxin/furan congener Toxic equivalency factor 2,3,7,8-tetrachlorinated dibenzo-p-dioxin 1 1,2,3,7,8-pentachlorinated dibenzo-p-dioxin 0.5 1,2,3,4,7,8-hexachlorinated dibenzo-p-dioxin 0.1 1,2,3,7,8,9-hexachlorinated dibenzo-p-dioxin 0.1 1,2,3,6...

40 CFR Table 4 to Subpart Dddd of... - Model Rule-Toxic Equivalency Factors

Code of Federal Regulations, 2010 CFR

2010-07-01

... Rule—Toxic Equivalency Factors Dioxin/furan congener Toxic equivalency factor 2,3,7,8-tetrachlorinated dibenzo-p-dioxin 1 1,2,3,7,8-pentachlorinated dibenzo-p-dioxin 0.5 1,2,3,4,7,8-hexachlorinated dibenzo-p-dioxin 0.1 1,2,3,7,8,9-hexachlorinated dibenzo-p-dioxin 0.1 1,2,3,6,7,8-hexachlorinated dibenzo-p-dioxin...

40 CFR Table 2 of Subpart Ec to... - Toxic Equivalency Factors

Code of Federal Regulations, 2010 CFR

2010-07-01

... Ec to Part 60—Toxic Equivalency Factors Dioxin/furan congener Toxic equivalency factor 2,3,7,8-tetrachlorinated dibenzo-p-dioxin 1 1,2,3,7,8-pentachlorinated dibenzo-p-dioxin 0.5 1,2,3,4,7,8-hexachlorinated dibenzo-p-dioxin 0.1 1,2,3,7,8,9-hexachlorinated dibenzo-p-dioxin 0.1 1,2,3,6,7,8-hexachlorinated dibenzo...

Fire Safety Aspects of Polymeric Materials. Volume 10. Mines and Bunkers

DTIC Science & Technology

1980-01-01

Formaldehyde and Melamine / Formaldehyde Resins The basic chemistry, properties, and applications of urea / formaldehyde and melamine / formaldehyde resins ... Formaldehyde and Melamine Formaldehyde Rosins 71 4.2.3.3 Unsaturated Polyester Resins 71 4.2.3.4 Epoxy Resins 72 4.2.3.5 Furan Resins 72 4.2.3.6 Amine...aldehyde — most frequently formaldehyde . Urea is often used as a modifying agent. The

Persistent Organic Pollutants in Serum and Several Different Fat Compartments in Humans

DTIC Science & Technology

2011-01-01

vena cava; A: aorta; P: pancreas; K: kidney; L: liver; S: stomach and spleen; C: colon; U: uterus; B: bladder; P: prostate. flame retardants , and...such as dioxins/furans, polychlori- nated biphenyls (PCBs), chlorinated pesticides, brominated Report Documentation Page Form ApprovedOMB No. 0704...perfluorinated compounds. Because of chlorine, bromine , or fluoride groups on the hydrocarbon rings or chains, these substances are resistant to degradation

New Concept Study for Repair of Bomb-Damaged Runways. Volume I. Concept Identification.

DTIC Science & Technology

1979-09-01

Expanded polystyrene beads would be pneumatically mixed with the cement to form a low density material. Initially, the ratio of foam to cement would...the combinations are presented with this concept. PRIMARY MATERIALS 0 Expanded polystyrene foam beads * Graded aggregate * Quick setting cement 61 E-4...probability of success - high ALTERNATE MATERIALS * Expanded polystyrene foam beads * Organic binders Furan Methyl Methacrylate Epoxy Aminos * Graded

The Fracture of Thermosetting Resins after Exposure to Water.

DTIC Science & Technology

1980-09-01

formaldehyde , urea - formaldehyde and melamine - formaldehyde resins , epoxides, unsaturated polyesters, diallyl phthalate resins , furanes and certain kinds...linked phenol- formaldehyde (27) and epoxy resins (22), but some work on the fracture surfaces of polyesters with varying flexibiliser additions has been...AO0-A099 975 KINGSTON POLYTECHNIC KINGSTON UPON THAMES (ENGLAND) F/G 11/9 THE FRACTURE OF THERMOSETTING RESINS AFTER EXPOSURE TO WATER.(U) SEP 80 6

40 CFR Table 7 to Subpart Dddd of... - Model Rule-Emission Limitations That Apply to Energy Recovery Units After May 20, 2011

Code of Federal Regulations, 2012 CFR

2012-07-01

... 36 parts per million dry volume Biomass—490 parts per million dry volumeCoal—59 parts per million dry... boilers. Use a span gas with a concentration of 1000 ppm or less for biomass-fed boilers. Dioxins/furans... nitrogen 76 parts per million dry volume Biomass—290 parts per million dry volumeCoal—340 parts per million...

40 CFR Table 6 to Subpart Cccc of... - Emission Limitations for Energy Recovery Units That Commenced Construction After June 4, 2010, or...

Code of Federal Regulations, 2012 CFR

2012-07-01

... parts per million dry volume Biomass—160 parts per million dry volume 30 day rolling average Carbon... concentration of 300 ppm or less for a biomass-fed boiler. Dioxins/furans (Total Mass Basis) No Total Mass Basis... Biomass—290 parts per million dry volumeCoal—340 parts per million dry volume 3-run average (1 hour...

40 CFR Table 6 to Subpart Cccc of... - Emission Limitations for Energy Recovery Units That Commenced Construction After June 4, 2010, or...

Code of Federal Regulations, 2011 CFR

2011-07-01

... parts per million dry volume Biomass—160 parts per million dry volume 30 day rolling average Carbon... concentration of 300 ppm or less for a biomass-fed boiler. Dioxins/furans (Total Mass Basis) No Total Mass Basis... Biomass—290 parts per million dry volumeCoal—340 parts per million dry volume 3-run average (1 hour...

New Drugs for CML

DTIC Science & Technology

2007-02-01

collection of information, including suggestions for reducing this burden to Department of Defense, Washington Headquarters Services , Directorate...AC22, K1P and AC19 as well as the Furans A103 and A105 have qualities which distinguish them from previously reported CML cell inhibitory drugs and...cost in the quality of life for those individuals so treated (3). Imatinib, a specific inhibitor of the Bcr-Abl tyrosine protein kinase, has

JBIR-23 and -24, novel anticancer agents from Streptomyces sp. AK-AB27.

PubMed

Motohashi, Keiichiro; Hwang, Ji-Hwan; Sekido, Yoshitaka; Takagi, Motoki; Shin-ya, Kazuo

2009-01-15

The screening for active compounds against malignant pleural mesothelioma (MPM) cells produced by Streptomyces sp. AK-AB27 resulted in the isolation of two compounds with a dodecahydrodibenzo[b,d]furan skeleton named JBIR-23 (1) and -24 (2). Their structures were established on the basis of extensive NMR and MS analyses. Compounds 1 and 2 exhibited cytotoxic effects against several MPM cell lines.

Determination of relative assay response factors for toxic chlorinated and brominated dioxins/furans using an enzyme immunoassay (EIA) and a chemically-activated luciferase gene expression cell bioassay (CALUX).

PubMed

Samara, Fatin; Gullett, Brian K; Harrison, Robert O; Chu, Andrew; Clark, George C

2009-04-01

Determination of toxic activity requires knowledge of both the concentration and toxicity to evaluate the risk for adverse human health and environmental effects. A chemically-activated luciferase gene expression cell bioassay system (CALUX) and an antibody-based method enzyme immunoassay (EIA) were used to detect the dioxin-like response of several polybrominated, polychlorinated, and polybrominated/chlorinated dibenzo-p-dioxins/furans (PBDDs/Fs, PCDDs/Fs, and PBCDDs/Fs, respectively). It has been suggested that the biological activity of the brominated and mixed bromo/chloro compounds is similar to their chlorinated analogues (measured by binding to the Ah receptor). PBDD/F, PCDD/F, and PBCDD/F laboratory standards exhibited biological activity ranging over three orders of magnitude. The highest relative potency (REP) values from CALUX analysis, when compared to 2,3,7,8-TCDD, were 2,3,7,8-TBDD at 0.99 (+/-0.07), 1,2,3,7,8-PeCDD at 0.69, and 2-Br-3,7,8-TriCDD at 0.72 (+/-0.02). Cross-reactivities were calculated using EIA for several PBDDs/Fs and PBCDDs. The highest percent cross-reactivity was found for 2,3,7,8-TBDD at 138 (+/-34%), and 2,3,7-TriBDD at 84 (+/-36%).

The Preparation and Properties of Thermo-reversibly Cross-linked Rubber Via Diels-Alder Chemistry.

PubMed

Polgar, Lorenzo Massimo; van Duin, Martin; Picchioni, Francesco

2016-08-25

A method for using Diels Alder thermo-reversible chemistry as cross-linking tool for rubber products is demonstrated. In this work, a commercial ethylene-propylene rubber, grafted with maleic anhydride, is thermo-reversibly cross-linked in two steps. The pending anhydride moieties are first modified with furfurylamine to graft furan groups to the rubber backbone. These pendant furan groups are then cross-linked with a bis-maleimide via a Diels-Alder coupling reaction. Both reactions can be performed under a broad range of experimental conditions and can easily be applied on a large scale. The material properties of the resulting Diels-Alder cross-linked rubbers are similar to a peroxide-cured ethylene/propylene/diene rubber (EPDM) reference. The cross-links break at elevated temperatures (> 150 °C) via the retro-Diels-Alder reaction and can be reformed by thermal annealing at lower temperatures (50-70 °C). Reversibility of the system was proven with infrared spectroscopy, solubility tests and mechanical properties. Recyclability of the material was also shown in a practical way, i.e., by cutting a cross-linked sample into small parts and compression molding them into new samples displaying comparable mechanical properties, which is not possible for conventionally cross-linked rubbers.

2-(Alkylamino)-3-aryl-6,7-dihydrobenzofuran-4(5H)-ones: Improved Synthesis and their Photophysical Properties

PubMed Central

Kumar, Manoj; Kumawat, Lokesh Kumar; Gupta, Vinod Kumar; Sharma, Anuj

2015-01-01

Furans are an important class of compounds and exhibit a diverse range of activities and properties. As such, improved synthetic access to furans is an important research goal. In the present report, a solvent- and catalyst-free reaction between 5,5-dimethyl-1,3-cyclohexanedione (dimedone), an aryl aldehyde and an isocyanide under microwave irradiation is presented. This method is significantly improved from previously described protocols in terms of applicability of wide ranging aryl aldehydes, better yields, shorter reaction times, facile work up and essentially no need of column chromatography. The photophysical properties of this series of compounds were studied for their possible applicability in the field of metal ion sensors. In solution, two compounds, 2-(cyclohexylamino)-3-(1H-indol-3-yl)-6,6-dimethyl-6,7-dihydrobenzofuran-4(5H)-one (1 i) and 2-(tert-butylamino)-3-(1H-indol-3-yl)-6,6-dimethyl-6,7-dihydrobenzofuran-4(5H)-one (1 j), underwent an observable color change from yellow to colorless in the presence of aluminum(III) ions. Further studies to investigate the UV absorption and luminescence behavior of these compounds revealed their utility as “naked-eye sensors” for aluminum detection. PMID:26491643

Declining Dioxin concentrations in the Rhone River, France, attest to the effectiveness of emissions controls

USGS Publications Warehouse

Van Metre, Peter C.; Babut, Marc; Mourier, Brice; Mahler, Barbara J.; Roux, Gwenaelle; Desmet, Marc

2015-01-01

Emission-control policies have been implemented in Europe and North America since the 1990s for polychlorodibenzodioxins (PCDDs) and furans (PCDFs). To assess the effect of these policies on temporal trends and spatial patterns for these compounds in a large European river system, sediment cores were collected in seven depositional areas along the Rhone River in France, dated, and analyzed for PCDDs and PCDFs. Results show concentrations increase in the downstream direction and have decreased temporally at all sites during the last two decades, with an average decrease of 83% from 1992 to 2010. The time for a 50% decrease in concentrations (t1/2) averaged 6.9 ± 2.6 and 9.1 ± 2.9 years for the sum of measured PCDDs and PCDFs, respectively. Congener patterns are similar among cores and indicate dominance of regional atmospheric deposition and possibly weathered local sources. Local sources are clearly indicated at the most downstream site, where concentrations of the most toxic dioxin, TCDD, are about 2 orders of magnitude higher than at the other six sites. The relatively steep downward trends attest to the effects of the dioxin emissions reduction policy in Europe and suggest that risks posed to aquatic life in the Rhone River basin from dioxins and furans have been greatly reduced.

Catalytic Hydrogenation and Hydrodeoxygenation of Furfural over Pt(111): A Model System for the Rational Design and Operation of Practical Biomass Conversion Catalysts.

PubMed

Taylor, Martin J; Jiang, Li; Reichert, Joachim; Papageorgiou, Anthoula C; Beaumont, Simon K; Wilson, Karen; Lee, Adam F; Barth, Johannes V; Kyriakou, Georgios

2017-04-20

Furfural is a key bioderived platform chemical whose reactivity under hydrogen atmospheres affords diverse chemical intermediates. Here, temperature-programmed reaction spectrometry and complementary scanning tunneling microscopy (STM) are employed to investigate furfural adsorption and reactivity over a Pt(111) model catalyst. Furfural decarbonylation to furan is highly sensitive to reaction conditions, in particular, surface crowding and associated changes in the adsorption geometry: furfural adopts a planar geometry on clean Pt(111) at low coverage, tilting at higher coverage to form a densely packed furfural adlayer. This switch in adsorption geometry strongly influences product selectivity. STM reveals the formation of hydrogen-bonded networks for planar furfural, which favor decarbonylation on clean Pt(111) and hydrogenolysis in the presence of coadsorbed hydrogen. Preadsorbed hydrogen promotes furfural hydrogenation to furfuryl alcohol and its subsequent hydrogenolysis to methyl furan, while suppressing residual surface carbon. Furfural chemistry over Pt is markedly different from that over Pd, with weaker adsorption over the former affording a simpler product distribution than the latter; Pd catalyzes a wider range of chemistry, including ring-opening to form propene. Insight into the role of molecular orientation in controlling product selectivity will guide the design and operation of more selective and stable Pt catalysts for furfural hydrogenation.

Self-healable interfaces based on thermo-reversible Diels-Alder reactions in carbon fiber reinforced composites.

PubMed

Zhang, W; Duchet, J; Gérard, J F

2014-09-15

Thermo-reversible Diels-Alder (DA) bonds formed between maleimide and furan groups have been used to generate an interphase between carbon fiber surface and an epoxy matrix leading to the ability of interfacial self-healing in carbon:epoxy composite materials. The maleimide groups were grafted on an untreated T700 carbon fiber from a three step surface treatment: (i) nitric acid oxidization, (ii) tetraethylenepentamine amination, and (iii) bismaleimide grafting. The furan groups were introduced in the reactive epoxy system from furfuryl glycidyl ether. The interface between untreated carbon fiber and epoxy matrix was considered as a reference. The interfacial shear strength (IFSS) was evaluated by single fiber micro-debonding test. The debonding force was shown to have a linear dependence with embedded length. The highest healing efficiency calculated from the debonding force was found to be about 82% more compared to the value for the reference interface. All the interphases designed with reversible DA bonds have a repeatable self-healing ability. As after the fourth healing, they can recover a relatively high healing efficiency (58% for the interphase formed by T700-BMI which is oxidized for 60 min during the first treatment step). Copyright © 2014 Elsevier Inc. All rights reserved.

Direct and simultaneous determination of representative byproducts in a lignocellulosic hydrolysate of corn stover via gas chromatography-mass spectrometry with a Deans switch.

PubMed

Zheng, Rongping; Zhang, Hongman; Zhao, Jing; Lei, Mingliu; Huang, He

2011-08-05

Pretreatment is one of the most important steps in producing fuel ethanol from lignocellulosic biomass. Simple, fast and accurate quantification of byproducts in lignocellulosic hydrolysates is critical to optimize the pretreatment procedures, but still a challenge. In this paper, a new GC-MS (SIM) method based on a Deans switch has been developed for the determination of byproducts in a corn stover hydrolysate. The Deans switch was incorporated into a hardware system that facilitated the direct aqueous injection (DAI) on GC-MS system. Simultaneous chromatographic separation and quantification of 18 byproducts including four aliphatic acids, five furan derivatives, four phenolic compounds and five others were achieved within 45 min. The detection limits of the presented method for various byproducts were in the range of 0.007-0.832 mg/L. The within-day and between-day precisions of the method were less than 6.0% (RSD, n=6). The accuracy of the method was confirmed with recoveries of 86-128%. A lignocellulosic hydrolysate sample of corn stover was successfully analyzed using this method, with aliphatic acids and furan derivatives accounting for 89.15% of the selected total byproducts. Copyright © 2011 Elsevier B.V. All rights reserved.

Multivariate Analysis and Prediction of Dioxin-Furan ...

EPA Pesticide Factsheets

Peer Review Draft of Regional Methods Initiative Final Report Dioxins, which are bioaccumulative and environmentally persistent, pose an ongoing risk to human and ecosystem health. Fish constitute a significant source of dioxin exposure for humans and fish-eating wildlife. Current dioxin analytical methods are costly, time-consuming, and produce hazardous by-products. A Danish team developed a novel, multivariate statistical methodology based on the covariance of dioxin-furan congener Toxic Equivalences (TEQs) and fatty acid methyl esters (FAMEs) and applied it to North Atlantic Ocean fishmeal samples. The goal of the current study was to attempt to extend this Danish methodology to 77 whole and composite fish samples from three trophic groups: predator (whole largemouth bass), benthic (whole flathead and channel catfish) and forage fish (composite bluegill, pumpkinseed and green sunfish) from two dioxin contaminated rivers (Pocatalico R. and Kanawha R.) in West Virginia, USA. Multivariate statistical analyses, including, Principal Components Analysis (PCA), Hierarchical Clustering, and Partial Least Squares Regression (PLS), were used to assess the relationship between the FAMEs and TEQs in these dioxin contaminated freshwater fish from the Kanawha and Pocatalico Rivers. These three multivariate statistical methods all confirm that the pattern of Fatty Acid Methyl Esters (FAMEs) in these freshwater fish covaries with and is predictive of the WHO TE

Copper-catalyzed synthesis of substituted furans and pyrroles by heterocyclodehydration and tandem heterocyclodehydration-hydration of 3-yne-1,2-diols and 1-amino-3-yn-2-ol derivatives.

PubMed

Gabriele, Bartolo; Veltri, Lucia; Plastina, Pierluigi; Mancuso, Raffaella; Vetere, Mabel V; Maltese, Vito

2013-05-17

CuCl2-catalyzed heterocyclodehydration of readily available 3-yne-1,2-diols and 1-amino-3-yn-2-ol derivatives afforded substituted furans and pyrroles, respectively, in good to high yields (53-99%) under mild conditions (MeOH as the solvent, 80-100 °C, 1-24 h). In the case of 2,2-dialkynyl-1,2-diols, bearing an additional alkynyl substituent at C-2, a cascade process, corresponding to copper-catalyzed heterocyclodehydration followed by acid-catalyzed hydration of the triple bond, was realized when the reaction was carried out in the presence of both CuCl2 and TsOH, leading to 3-acylfurans in one step and high yields (75-84%). Under the same conditions, N-Boc-2-alkynyl-1-amino-3-yn-2-ols were converted into the corresponding N-unsubstituted 3-acylpyrroles in low to fair yields (19-59%). However, working in the presence of added water and a large excess of CO2 (40 atm), in addition to CuCl2 and TsOH, caused a significant improvement of the yields of 3-acylpyrroles (68-87%), thus making the method of general synthetic applicability.

TECHNOLOGIES FOR MONITORING AND MEASUREMENT ...

EPA Pesticide Factsheets

A demonstration of technologies for determining the presence of dioxin and dioxin-like compounds in soil and sediment was conducted under EPA's Superfund Innovative Technology Evaluation Program in Saginaw, Michigan in April 2004. This report describes the performance evaluation of CAPE Technologies DF-1 Dioxin/Furan and PCB TEQ Immunoassay Kits. The kits are immunoassay techniques that report the total toxicity equivalents (TEQ) of dioxin/furans and polychlorinated biphenyls (PCBs. The technology results were compared to high resolution mass spectrometry TEQ results generated using EPA Methods 1613B and 1668A.The CAPE Technologies kits generally reported data higher than the certified PE and reference laboratory values. The technologys estimated MDL was 12 to 33 pg/g TEQ. Results from this demonstration suggest that the CAPE Technologies kits could be an effective screening tool for determining sample results above and below 20 pg/g TEQ and even more effective as a screen for sample above and below 50 pg/g TEQ, particularly considering that both the cost ($59,234 vs. $398,029) and the time (3 weeks vs. 8 months) to analyze the 209 demonstration samples were significantly less than those of the reference laboratory. The objective of this program is to promote the acceptance and use of innovative field technologies by providing well-documented performance and cost data obtained from field demonstrations.

Dihedral angle control to improve the charge transport properties of conjugated polymers in organic field effect transistors

NASA Astrophysics Data System (ADS)

Dharmapurikar, Satej S.; Chithiravel, Sundaresan; Mane, Manoj V.; Deshmukh, Gunvant; Krishnamoorthy, Kothandam

2018-03-01

Diketopyrrolopyrrole (DPP) and i-Indigo (i-Ind) are two monomers that are widely explored as active materials in organic field effect transistor and solar cells. These two molecules showed impressive charge carrier mobility due to better packing that are facilitated by quadrupoles. We hypothesized that the copolymers of these monomers would also exhibit high charge carrier mobility. However, we envisioned that the dihedral angle at the connecting point between the monomers will play a crucial role in packing as well as charge transport. To understand the impact of dihedral angle on charge transport, we synthesized three copolymers, wherein the DPP was sandwiched between benzenes, thiophenes and furans. The copolymer of i-Indigo and furan comprising DPP showed a band gap of 1.4 eV with a very high dihedral angle of 179°. The polymer was found to pack better and the coherence length was found to be 112 Å. The hole carrier mobility of these polymer was found to be highest among the synthesized polymer i.e. 0.01 cm2/vs. The copolymer comprising benzene did not transport hole and electrons. The dihedral angle at the connecting point between i and Indigo and benzene DPP was 143 Å, which the packing and consequently charge transport properties.

Catalytic Hydrogenation and Hydrodeoxygenation of Furfural over Pt(111): A Model System for the Rational Design and Operation of Practical Biomass Conversion Catalysts

PubMed Central

2017-01-01

Furfural is a key bioderived platform chemical whose reactivity under hydrogen atmospheres affords diverse chemical intermediates. Here, temperature-programmed reaction spectrometry and complementary scanning tunneling microscopy (STM) are employed to investigate furfural adsorption and reactivity over a Pt(111) model catalyst. Furfural decarbonylation to furan is highly sensitive to reaction conditions, in particular, surface crowding and associated changes in the adsorption geometry: furfural adopts a planar geometry on clean Pt(111) at low coverage, tilting at higher coverage to form a densely packed furfural adlayer. This switch in adsorption geometry strongly influences product selectivity. STM reveals the formation of hydrogen-bonded networks for planar furfural, which favor decarbonylation on clean Pt(111) and hydrogenolysis in the presence of coadsorbed hydrogen. Preadsorbed hydrogen promotes furfural hydrogenation to furfuryl alcohol and its subsequent hydrogenolysis to methyl furan, while suppressing residual surface carbon. Furfural chemistry over Pt is markedly different from that over Pd, with weaker adsorption over the former affording a simpler product distribution than the latter; Pd catalyzes a wider range of chemistry, including ring-opening to form propene. Insight into the role of molecular orientation in controlling product selectivity will guide the design and operation of more selective and stable Pt catalysts for furfural hydrogenation. PMID:29225721

Effect of lignocellulose-derived inhibitors on the growth and D-lactic acid production of Sporolactobacillus inulinus YBS1-5.

PubMed

Bai, Zhongzhong; Gao, Zhen; He, Bingfang; Wu, Bin

2015-10-01

The impact of lignocellulose-derived inhibitors on the cell growth and D-lactic production of Sporolactobacillus inulinus YBS1-5 was investigated. At high concentrations, both furans and phenolics, such as furfural, HMF, syringaldehyde and vanillin, affected cell growth and D-lactic acid production and syringaldehyde exhibited the highest. Further experiments showed that only vanillin caused cellular membrane damage. Based on the Biolog approach, in vivo studies on intact S. inulinus cells indicated that phenolics had a stronger inhibitory effect than furan derivatives on the metabolic activity of the concerned substrates related with the key enzymes of D-lactic acid fermentation. The direct in vitro inhibitory effect of the model compounds on the four key enzymes displayed similar patterns. Syringaldehyde was the strongest inhibitor. In general, comparison with published results for other microorganisms indicated that strain YBS1-5 was a robust microorganism against inhibitors of lignocellulose hydrolysate. Notably, in concentrated corn stover hydrolysate, S. inulinus YBS1-5 produced 70.7 g/L D-lactic acid, which was 87.7 % of the yield from the control experiment. However, the fermentation time was prolonged 36 h. In order to improve fermentation rate, a detoxification technology or more robust mutant to phenolics especially syringaldehyde should be developed.