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Sample records for du methyl tert-butyl

  1. Degradation of a recalcitrant xenobiotic compound: methyl tert-butyl ether (MTBE) metabolism by mycobacterium austroafricanum; Degradation d'un compose xenobiotique recalcitrant: metabolisme du methyl tert-butyl ether (MTBE) par mycobacterium austroafricanum IFP 2012

    Energy Technology Data Exchange (ETDEWEB)

    Francois, A.

    2002-11-01

    Methyl tert-butyl ether (MTBE) is introduced up to 15% (vol/vol) in gasoline in order to obtain a good octane number and to prevent carbon monoxide emissions. However, as a consequence of storage tanks leakage, MTBE became one of the major pollutants of aquifers because of its very low biodegradability. The present study aimed at investigating the biodegradation of MTBE by Mycobacterium austroafricanum IFP 2012. The MTBE metabolic pathway was partially elucidated owing to the identification of some intermediates (tert-butyl formate (TBF), tert-butyl alcohol (TBA), a-hydroxy-isobutyric acid and acetone) and some enzymatic activities (MTBE/TBA monooxygenase (non hemic and inducible), TBF esterase, 2-propanol: NDMA oxidoreductase and another monooxygenase involved in acetone degradation). The involvement of TBF and the requirement of cobalt could be explanations for the low natural attenuation of MTBE; whereas the methoxy group does not seem to be implicated. (author)

  2. An efficient and highly selective ortho-tert-butylation of p-cresol with methyl tert-butyl ether catalyzed by sulfonated ionic liquids

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    Alamdari Reza Fareghi

    2014-01-01

    Full Text Available A novel series of sulfonic acid-functionalized ionic liquids (SFILs was found to act as efficient catalysts for ortho-tert-butylation of p-cresol with methyl tert-butyl ether (MTBE as the tert-butylating agent without an added solvent. The mono o-tert-butylated product was obtained in up to 80.4% isolated yield and 95.2% selectivity under such green conditions. No O-tert-butylated byproducts were formed.

  3. Microbial degradation of methyl tert-butyl ether and tert-butyl alcohol in the subsurface

    Science.gov (United States)

    Schmidt, Torsten C.; Schirmer, Mario; Weiß, Holger; Haderlein, Stefan B.

    2004-06-01

    The fate of fuel oxygenates such as methyl tert-butyl ether (MTBE) in the subsurface is governed by their degradability under various redox conditions. The key intermediate in degradation of MTBE and ethyl tert-butyl ether (ETBE) is tert-butyl alcohol (TBA) which was often found as accumulating intermediate or dead-end product in lab studies using microcosms or isolated cell suspensions. This review discusses in detail the thermodynamics of the degradation processes utilizing various terminal electron acceptors, and the aerobic degradation pathways of MTBE and TBA. It summarizes the present knowledge on MTBE and TBA degradation gained from either microcosm or pure culture studies and emphasizes the potential of compound-specific isotope analysis (CSIA) for identification and quantification of degradation processes of slowly biodegradable pollutants such as MTBE and TBA. Microcosm studies demonstrated that MTBE and TBA may be biodegradable under oxic and nearly all anoxic conditions, although results of various studies are often contradictory, which suggests that site-specific conditions are important parameters. So far, TBA degradation has not been shown under methanogenic conditions and it is currently widely accepted that TBA is a recalcitrant dead-end product of MTBE under these conditions. Reliable in situ degradation rates for MTBE and TBA under various geochemical conditions are not yet available. Furthermore, degradation pathways under anoxic conditions have not yet been elucidated. All pure cultures capable of MTBE or TBA degradation isolated so far use oxygen as terminal electron acceptor. In general, compared with hydrocarbons present in gasoline, fuel oxygenates biodegrade much slower, if at all. The presence of MTBE and related compounds in groundwater therefore frequently limits the use of in situ biodegradation as remediation option at gasoline-contaminated sites. Though degradation of MTBE and TBA in field studies has been reported under oxic

  4. Biodegradation of methyl tert-butyl ether by Kocuria sp.

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    Kiković Dragan D.

    2012-01-01

    Full Text Available Methyl tert-butyl ether (MTBE has been used to replace the toxic compounds from gasoline and to reduce emission of air pollutants. Due to its intensive use, MTBE has become one of the most important environment pollutants. The aim of this paper is isolation and identification of the bacteria from wastewater sample of “HIP Petrohemija” Pančevo (Serbia, capable of MTBE biodegradation. The results of the investigation showed that only the bacterial isolate 27/1 was capable of growth on MTBE. The result of sequence analyzes of 16S rDNA showed that this bacterial isolate belongs to the Kocuria sp. After the incubation period of 86 days, the degradation rates of initial MTBE concentration of 25 and 125 μg/ml were 55 and 36%, respectively. These results indicated that bacteria Kocuria sp. is successfully adapted on MTBE and can be potentially used in bioremediation of soils and waters contaminated with MTBE.

  5. Toxicity of methyl-tert-butyl ether to freshwater organisms.

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    Werner, I; Koger, C S; Deanovic, L A; Hinton, D E

    2001-01-01

    Increased input of the fuel oxygenate methyl-tert-butyl ether (MTBE) into aquatic systems has led to concerns about its effect(s) on aquatic life. As part of a study conducted by University of California scientists for the State of California, the Aquatic Toxicology Laboratory, UC Davis, reviewed existing literature on toxicity of MTBE to freshwater organisms, and new information was generated on chronic, developmental toxicity in fish, and potential toxicity of MTBE to California resident species. Depending on time of exposure and endpoint measured, MTBE is toxic to various aquatic organisms at concentrations of 57-> 1000 mg/l (invertebrates), and 388-2600 mg/l (vertebrates). Developmental effects in medaka (Oryzias latipes) were not observed at concentrations up to 480 mg/l, and all fish hatched and performed feeding and swimming in a normal manner. Bacterial assays proved most sensitive with toxicity to Salmonella typhimurium measured at 7.4 mg/l within 48 h. In microalgae, decreased growth was observed at 2400 and 4800 mg/l within 5 days. MTBE does not appear to bioaccumulate in fish and is rapidly excreted or metabolized. Collectively, the available data suggests that at environmental MTBE exposure levels found in surface waters (toxic to aquatic life. However, more information is needed on chronic and sublethal effects before we can eliminate the possibility of risk to aquatic communities at currently detected concentrations.

  6. APPLICATION OF PHOTOCATALYTIC PROCESS FOR REMOVAL OF METHYL TERT-BUTYL ETHER FROM HIGHLYCONTAMINATED WATER

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    A. Mesdaghinia

    2007-09-01

    Full Text Available The oxygenate methyl tert-butyl ether is added to gasoline to increase the octane level and to reduce carbon monoxide and hydrocarbon emissions by vehicles. The high mobility, water solubility, and resistance to natural attenuation associated with methyl tert-butyl ether may result in contamination of ground and surface waters. In this research the degradation of aqueous methyl tert-butyl ether at relatively high concentrations was investigated by UV-vis/TiO2/H2O2 photocatalytic process. The effect of important operational parameters such as pH, amount of H2O2, catalyst loading, and irradiation time were also studied. Concentrations of methyl tert-butyl ether and intermediates such as tert-butyl formate and tert-butyl alcohol were measured over a 180 min period using a gas chromatograph equipped with flame ionization detector and combined with headspace sampler. Results showed that the time required for complete degradation increased from 30 to 180min, when the initial concentration was increased from 10 to 500mg/L. The first order rate constant for degradation of methyl tert-butyl ether from the hydroxyl radical was estimated to be 0.177 to 0.022 1/min as the concentration increased from 10 to 500mg/L. Study on the overall mineralization monitored by total organic carbon (TOC analysis showed that in the initial concentration of 100mg/L methyl tert-butyl ether, complete mineralization was obtained after 110min under UV-vis/TiO2/H2O2 photocatalytic process.

  7. Hydrolysis of tert-butyl formate: Kinetics, products, and implications for the environmental impact of methyl tert-butyl ether

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    Church, Clinton D.; Pankow, James F.; Tratnyek, Paul G.

    1999-01-01

    Asessing the environmental fate of methyl tert-butyl ether (MTBE) has become a subject of renewed interest because of the large quantities of this compound that are being used as an oxygenated additive in gasoline. Various studies on the fate of MTBE have shown that it can be degraded to tert-butyl formate (TBF), particularly in the atmosphere. Although it is generally recognized that TBF is subject to hydrolysis, the kinetics and products of this reaction under environmentally relevant conditions have not been described previously. In this study, we determined the kinetics of TBF hydrolysis as a function of pH and temperature. Over the pH range of 5 to 7, the neutral hydrolysis pathway predominates, with kN = (1.0 ± 0.2) × 10−6/s. Outside this range, strong pH effects were observed because of acidic and basic hydrolyses, from which we determined that kA = (2.7 ± 0.5) × 10−3/(M·s) and kB = 1.7 ± 0.3/(M·s). Buffered and unbuffered systems gave the same hydrolysis rates for a given pH, indicating that buffer catalysis was not significant under the conditions tested. The activation energies corresponding to kN, kA, and kBwere determined to be 78 ± 5, 59 ± 4, and 88 ±11 kJ/mol, respectively. In all experiments, tert-butyl alcohol was found at concentrations corresponding to stoichiometric formation from TBF. Based on our kinetics data, the expected half-life for hydrolysis of TBF at pH = 2 and 4°C (as per some standard preservation protocols for water sampling) is 6 h. At neutral pH and 22°C, the estimated half-life is 5 d, and at pH = 11 and 22°C, the value is only 8 min.

  8. Human gallbladder morphology after gallstone dissolution with methyl tert-butyl ether.

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    vanSonnenberg, E; Zakko, S; Hofmann, A F; D'Agostino, H B; Jinich, H; Hoyt, D B; Miyai, K; Ramsby, G; Moossa, A R

    1991-06-01

    The effects of methyl tert-butyl ether exposure on the human gallbladder in five patients who were treated for gallstones by contact dissolution is described. Two patients underwent cholecystectomy within 1 week of methyl tert-butyl ether treatment, one patient 2 weeks after, another 10 weeks after, and one 12 weeks after. Indications for cholecystectomy were bilirubinate stones (resistant to methyl tert-butyl ether), catheter dislodgement, bile leakage, and gallstone recurrence (2 patients). Gallstones were dissolved completely in three patients, there was approximately 50% stone reduction in one patient, and no dissolution occurred in the fifth patient. Each gallbladder was examined grossly and histologically. Electron microscopic evaluation was performed in one cases. Typical inflammatory findings of chronic cholecystitis were observed in each gallbladder and were most conspicuous in the submucosa; the mucosal and serosal surfaces were intact. Mild acute inflammatory changes were noted in the submucosa in the two patients with the shortest interval between methyl tert-butyl ether administration and cholecystectomy. There were no ulcerations in the mucosa and no unusual wall thickening or fibrosis in any patient. These observations support the safety of methyl tert-butyl ether perfusion in the human gallbladder; the mild acute changes may be a transient and reversible phenomenon.

  9. Estimation of the fraction of biologically active methyl tert-butyl ether degraders in a heterogeneous biomass sample

    DEFF Research Database (Denmark)

    Waul, Christopher Kevin; Arvin, Erik; Schmidt, Jens Ejbye

    2008-01-01

    The fraction of biologically active methyl tert-butyl ether degraders in reactors is just as important for prediction of removal rates as knowledge of the kinetic parameters. The fraction of biologically active methyl tert-butyl ether degraders in a heterogeneous biomass sample, taken from a packed...

  10. PHOTOCATALYTIC OXIDATION OF METHYL-TERT-BUTYL ETHER FOR DRINKING WATER TREATMENT

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    The photo-oxidation of methyl tert-butyl ether (MTBE) in water was investigated to determine the feasibility of using photocatalysis for the treatment of MTBE-contaminated drinking water. The feasibility assessment was conducted using slurries of titanium dioxide in both a photo-...

  11. TREATMENT OF METHYL TERT-BUTYL ETHER CONTAMINATED WATER USING PHOTOCATALYSIS

    Science.gov (United States)

    The feasibility of photo-oxidation treatment of methyl tert-butyl ether (MTBE) in water was investigated in three ways, 1) using a slurry falling film photo-reactor, 2) a batch solar reactor system, and 3) a combination of air-stripping and gas phase photooxidation system. MTBE-c...

  12. tert-Butyl 2-methyl-2-(4-methylbenzoylpropanoate

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    Graham B. Gould

    2010-02-01

    Full Text Available The title compound, C16H22O3, is bent with a dihedral angle of 75.3 (1° between the mean planes of the benzene ring and a group encompassing the ester functionality (O=C—O—C. In the crystal, the molecules are linked into infinite chains held together by weak C—H...O hydrogen-bonded interactions between an H atom on the benzene ring of one molecule and an O atom on the ketone functionality of an adjacent molecule. The chains are arranged with neighbouring tert-butyl and dimethyl groups on adjacent chains exhibiting hydrophobic stacking, with short C—H...H—C contacts (2.37 Å between adjacent chains

  13. Biodegradation of the gasoline oxygenates methyl tert-butyl ether, ethyl tert-butyl ether, and tert-amyl methyl ether by propane-oxidizing bacteria.

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    Steffan, R J; McClay, K; Vainberg, S; Condee, C W; Zhang, D

    1997-11-01

    Several propane-oxidizing bacteria were tested for their ability to degrade gasoline oxygenates, including methyl tert-butyl ether (MTBE), ethyl tert-butyl ether (ETBE), and tert-amyl methyl ether (TAME). Both a laboratory strain and natural isolates were able to degrade each compound after growth on propane. When propane-grown strain ENV425 was incubated with 20 mg of uniformly labeled [14C]MTBE per liter, the strain converted > 60% of the added MTBE to 14CO2 in production of nearly stoichiometric amounts of tert-butyl alcohol (TBA), while the initial oxidation of TAME resulted in the production of tert-amyl alcohol. The methoxy methyl group of MTBE was oxidized to formaldehyde and ultimately to CO2. TBA was further oxidized to 2-methyl-2-hydroxy-1-propanol and then 2-hydroxy isobutyric acid; however, neither of these degradation products was an effective growth substrate for the propane oxidizers. Analysis of cell extracts of ENV425 and experiments with enzyme inhibitors implicated a soluble P-450 enzyme in the oxidation of both MTBE and TBA. MTBE was oxidized to TBA by camphor-grown Pseudomonas putida CAM, which produces the well-characterized P-450cam, but not by Rhodococcus rhodochrous 116, which produces two P-450 enzymes. Rates of MTBE degradation by propane-oxidizing strains ranged from 3.9 to 9.2 nmol/min/mg of cell protein at 28 degrees C, whereas TBA was oxidized at a rate of only 1.8 to 2.4 nmol/min/mg of cell protein at the same temperature.

  14. Selection and identification of bacterial strains with methyl-tert-butyl ether, ethyl-tert-butyl ether, and tert-amyl methyl ether degrading capacities.

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    Purswani, Jessica; Pozo, Clementina; Rodríguez-Díaz, Marina; González-López, Jesús

    2008-11-01

    Nine bacterial strains isolated from two hydrocarbon-contaminated soils were selected because of their capacity for growth in culture media amended with 200 mg/L of one of the following gasoline oxygenates: Methyl-tert-butyl ether (MTBE), ethyl-tert-butyl ether (ETBE), and tert-amyl methyl ether (TAME). These strains were identified by amplification of their 16S rRNA gene, using fDl and rD1 primers, and were tested for their capacity to grow and biotransform these oxygenates in both mineral and cometabolic media. The isolates were classified as Bacillus simplex, Bacillus drentensis, Arthrobacter sp., Acinetobacter calcoaceticus, Acinetobacter sp., Gordonia amicalis (two strains), Nocardioides sp., and Rhodococcus ruber. Arthrobacter sp. (strain MG) and A. calcoaceticus (strain M10) consumed 100 (cometabolic medium) and 82 mg/L (mineral medium) of oxygenate TAME in 21 d, respectively, under aerobic conditions. Rhodococcus ruber (strain E10) was observed to use MTBE and ETBE as the sole carbon and energy source, whereas G. amicalis (strain T3) used TAME as the sole carbon and energy source for growth. All the bacterial strains transformed oxygenates better in the presence of an alternative carbon source (ethanol) with the exception of A. calcoaceticus (strain M10). The capacity of the selected strains to remove MTBE, ETBE, and TAME looks promising for application in bioremediation technologies.

  15. Photo catalytic degradation of methyl tert-Butyl Ether (MTBE) from contaminated water: complete mineralization

    Energy Technology Data Exchange (ETDEWEB)

    Eslami, A.; Nasseri, S.; Maleki, A.; Aghvami, T.

    2009-07-01

    Methyl tert-butyl ether (MTBE) has been commercially used as an octane enhancer to replace tetraethyl lead in gasoline since 1979. The high mobility, water solubility, and resistance to natural attenuation associated with MTBE may result in contamination of ground and surface waters. In this investigation the degradation of aqueous MTBE at relatively high concentrations was studied by UV-vis/TiO{sub 2}/O{sub 2} photo catalytic process. The effect of important operational parameters such as ph, oxygen flow, catalyst loading, and irradiation time were also studied. (Author)

  16. Removal of Methyl Tert-Butyl Ether (MTBE from Contaminated Water by Photocatalytic Process

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    A Eslami

    2009-06-01

    Full Text Available "nBackground: Methyl tert-butyl ether (MTBE has been commercially used as an octane enhancer to replace tetraethyl lead in gasoline since 1979. The high mobility, water solubility, and resistance to natural attenuation associated with MTBE may re­sult in contamination of ground and surface waters. In this investigation the degradation of aqueous MTBE at relatively high concentrations was studied by UV-vis/TiO2/O2 photocatalytic process. The effect of important operational parameters such as pH, oxygen flow, catalyst loading, and irradiation time were also studied."nMethods:Concentration of MTBE and intermediates such as tert-butyl formate (TBF and tert-butyl alcohol (TBA were meas­ured using a gas chromatograph equipped with flam ionization detector and combined with headspace sampler."nResults: The time required for complete degradation increased from 15 to 150 min, when the initial concentration was in­creased from 10 to 500 mg/L. The first order rate constant for degradation of MTBE from the hydroxyl radical was esti­mated to be 0.266 to 0.033 min-1 as the concentration increased from 10 to 500 mg/L. Study on the overall mineralization moni­tored by total organic carbon (TOC analysis showed that in the initial concentration of 100 mg/L MTBE, complete min­eralization was obtained after 110 min under UV-vis/TiO2/O2 photocatalytic process."nConclusion: The data presented in this paper clearly indicate that UV/TiO2/O2 advanced oxidation process provides an effi­cient treatment alternative for the remediation of MTBE contaminated water.  

  17. Gall stone dissolution with methyl tert-butyl ether: how to avoid complications.

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    Hellstern, A; Leuschner, M; Frenk, H; Dillinger, H W; Caspary, W; Leuschner, U

    1990-01-01

    Fifty of 52 patients with cholesterol gall bladder stones were treated with methyl tert-butyl ether. In 48 of 50 (96%) patients the stones dissolved after an average interval of 9.5 hours. Mean stone size was 1.7 cm (0.5-3.3 cm), mean stone number was 14.6 (1-70). Twelve patients (24%) complained of nausea, a burning sensation, or vomiting. In one patient bile leakage occurred and another suffered haematobilia (4%). The puncture set was improved, and a special basket was developed to extract stones that had escaped into the cystic duct. To prevent bile leakage or haemorrhage from the incision channel, a tissue adhesive was injected into the channel or ceruletid was administered subcutaneously before removing the catheter to induce contraction of the gall bladder. Thus we were able to treat 44 patients without any complications. Nausea and vomiting could be reduced if the treatment time was kept short and the perfusion volume was as low as possible. Methyl tert-butyl ether treatment is a successful treatment of gall bladder stones with few complications. Images Figure 1 Figure 2 Figure 3 Figure 4 PMID:2387519

  18. Method for determination of methyl tert-butyl ether in gasoline by gas chromatography.

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    Achten, C; Püttmann, W

    2001-03-02

    A simple method for the determination of methyl tert-butyl ether (MTBE) in gasoline has been developed. The separation of MTBE from other analytes was controlled by the use of gas chromatography-mass spectrometry in the full scan mode using the characteristic primary, secondary and tertiary ions m/z 73, 57 and 43. The sample mass spectrum did not show any superimposition of other analytes. The separation from the common gasoline component 2-methylpentane was sufficient for reliable quantitation. An application of the developed conditions using gas chromatography with flame ionization detection was performed by the analysis of regular, euro super, super premium unleaded and 'Optimax' gasoline from petrol stations in the area of Frankfurt/Main, Germany. Regular unleaded gasoline shows an average MTBE content of 0.4% (w/w), whereas the MTBE content in euro super gasoline varies between 0.4 and 4.2% (w/w). The blending of MTBE to super premium has increased from 8.2% (w/w) in 1998 to 9.8% (w/w) on average in 1999. The recently introduced gasoline 'Optimax' shows an average MTBE content of 11.9% (w/w). The presented method might also be used for the analysis of other ethers, such as ethyl tert-butyl ether, which requires the use of another internal standard.

  19. Biodegradation of Methyl tert-Butyl Ether by Co-Metabolism with a Pseudomonas sp. Strain

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    Shanshan Li

    2016-09-01

    Full Text Available Co-metabolic bioremediation is supposed to be an impressive and promising approach in the elimination technology of methyl tert-butyl ether (MTBE, which was found to be a common pollutant worldwide in the ground or underground water in recent years. In this paper, bacterial strain DZ13 (which can co-metabolically degrade MTBE was isolated and named as Pseudomonas sp. DZ13 based on the result of 16S rRNA gene sequencing analysis. Strain DZ13 could grow on n-alkanes (C5-C8, accompanied with the co-metabolic degradation of MTBE. Diverse n-alkanes with different carbon number showed a significant influence on the degradation rate of MTBE and accumulation of tert-butyl alcohol (TBA. When Pseudomonas sp. DZ13 co-metabolically degraded MTBE with n-pentane as the growth substrate, a higher MTBE-degrading rate (Vmax = 38.1 nmol/min/mgprotein, Ks = 6.8 mmol/L and lower TBA-accumulation was observed. In the continuous degradation experiment, the removal efficiency of MTBE by Pseudomonas sp. Strain DZ13 did not show an obvious decrease after five times of continuous addition.

  20. The mechanism of catalytic methylation of 2-phenylpyridine using di-tert-butyl peroxide.

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    Sharma, Akhilesh K; Roy, Dipankar; Sunoj, Raghavan B

    2014-07-14

    The mechanism of palladium chloride-catalyzed direct methylation of arenes with peroxides is elucidated by using the energetics computed at the M06 density functional theory. The introduction of a methyl group by tert-butyl peroxides at the ortho-position of a prototypical 2-phenyl pyridine, a commonly used substrate in directed C-H functionalization reactions, is examined in detail by identifying the key intermediates and transition states involved in the reaction sequence. Different possibilities that differ in terms of the site of catalyst coordination with the substrate and the ensuing mechanism are presented. The important mechanistic events involved are (a) an oxidative or a homolytic cleavage of the peroxide O-O bond, (b) C-H bond activation, (c) C-C bond activation, and (d) reductive elimination involving methyl transfer to the aromatic ring. We have examined both radical and non-radical pathways. In the non-radical pathway, the lowest energy pathway involves C-H bond activation prior to the coordination of the peroxide to palladium, which is subsequently followed by the O-O bond cleavage of the peroxide and the C-C bond activation. Reductive elimination in the resulting intermediate leads to the vital C-C bond formation between methyl and aryl carbon atoms. In the non-radical pathway, the C-C bond activation is higher in energy and has been identified as the rate-limiting step of this reaction. In the radical pathway, however, the activation barrier for the C-C bond cleavage is lower than for the peroxide O-O bond cleavage. A combination of a radical pathway up to the formation of a palladium methyl intermediate and a subsequent non-radical pathway has been identified as the most favored pathway for the title reaction. The predicted mechanism is in good agreement with the experimental observations on PdCl2 catalyzed methylation of 2-phenyl pyridine using tert-butyl peroxide.

  1. SYNTHESIS OF METHYL TERT-BUTYL ETHER CATALYZED BY ACIDIC ION-EXCHANGE RESINS - INFLUENCE OF THE PROTON ACTIVITY

    NARCIS (Netherlands)

    PANNEMAN, HJ; BEENACKERS, AACM

    1995-01-01

    The catalytic activity of various strong acid ion-exchange resins on the synthesis of methyl tert-butyl ether (MtBE) from methanol and isobutene has been investigated. Relative to Amberlyst 15, Kastel CS 381 and Amberlyst CSP have similar rate constants, whereas Duolite ES 276 and Amberlyst XE 307 h

  2. INTERACTION OF METHYL-TERT BUTYL ETHER AND WATER STRESS ON SEED GERMINATION AND SEEDLING GROWTH IN SOIL MICROCOSMS

    Science.gov (United States)

    Methyl tert-butyl ether (MTBE) is a widespread contaminant in surface and ground water in the United States. Frequently irrigation is used to water fields to germinate planted seeds and sustain plant growth. A likely possibility exists that water used may have some MTBE. Our s...

  3. INTERACTION OF METHYL-TERT BUTYL ETHER AND WATER STRESS ON SEED GERMINATION AND SEEDLING GROWTH IN SOIL MICROCOSMS

    Science.gov (United States)

    Methyl tert-butyl ether (MTBE) is a widespread contaminant in surface and ground water in the United States. Frequently irrigation is used to water fields to germinate planted seeds and sustain plant growth. A likely possibility exists that water used may have some MTBE. Our s...

  4. Isolation and Initial Characterization of A Pure Cultures Capable to Degradation Methyl tert- Butyl Ether (MTBE

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    A Nikpey

    2006-07-01

    Full Text Available Methyl tert-butyl ether (MTBE, a gasoline octane enhancer, was introduced as a substitute for lead tetraethyl over 30 years ago. Widespread use of MTBE in gasoline, has introduced MTBE into the environment compartments, mostly into the under ground and surface water and water as a second most frequently detected contaminant. In this study, we have isolated pure cultures from bacterial consortium capable to use MTBE as a sole carbon and energy source. MTBE biodegradation rate was measured in headspace by gas chromatography. Initial liner rates of biodegradation by Pinpoint and white strains were found 2.9 mg and 3 mg MTBE hˉ1 gˉ1 wet biomass, respectively. The results of 16S rDNA PCR disclosed similarities in the banding patterns between the cultures, and the known degrading strain PM1. The results of this study suggest promising perspectives for engineering the in situ bioremediation of MTBE.

  5. Degradation of aqueous methyl tert-butyl ether by photochemical, biological, and their combined processes

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    Azadeh Asadi

    2006-01-01

    Full Text Available The degradation of aqueous methyl tert-butyl ether (MTBE at relatively high concentrations was investigated by various photo-induced oxidation processes such as UV/H2O2 and UV/TiO2 as well as biological processes and their combination. It was shown that the degradation of MTBE by UV/H2O2 and TiO2 photocatalytic followed a first-order model with apparent rate constant of 1.31×10−1 and 1.21×10−2 min-1, respectively. It was observed that UV/H2O2/TiO2 process did not have any advantages over each of the other processes alone. The biodegradation of methyl tert-butyl ether (MTBE was evaluated using aerobic mixed culture with three different approaches, including ultimate biological oxygen demand (BODU assessment, nonacclimated, and acclimated mixed cultures. The apparent rate constant for the biodegradation of MTBE by nonacclimated mixed culture was 4.36×10−2 day-1. It was shown that the acclimatization of the mixed cultures enhanced the rate of biodegradation of MTBE to 3.24×10−1mg L-1h-1. Finally, the effects of the photocatalytic pretreatment of aqueous MTBE on its subsequent biological treatment were studied. It was observed that the rate of bioreaction was not enhanced and the photocatalytic pretreatment had adverse effects on its biological treatment so that the apparent rate constant decreased to 2.83×10−1 mg L-1h-1.

  6. Biological Activity of Methyl tert-butyl Ether in Relation to Soil Microorganisms has a Negative Environmental Impact

    OpenAIRE

    Gholam H.S. Bonjar

    2005-01-01

    Fuel oxygenates are added to gasoline to enhance combustion efficiency of automobiles and reduce air pollution. Methyl tert-butyl ether (MTBE) is the most commonly used oxygenate because of its low cost, high-octane level and ease of blending with gasoline. However, due to its water solubility, high mobility and low biodegradability it leaches in soil subsurface at the speed of groundwater. Amending gasoline with MTBE has made a widespread contamination of groundwater, surface waters in coast...

  7. Artificial Neural Network Approach to Predict Biodiesel Production in Supercritical tert-Butyl Methyl Ether

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    Obie Farobie

    2016-05-01

    Full Text Available In this study, for the first time artificial neural network was used to predict biodiesel yield in supercritical tert-butyl methyl ether (MTBE. The experimental data of biodiesel yield conducted by varying four input factors (i.e. temperature, pressure, oil-to-MTBE molar ratio, and reaction time were used to elucidate artificial neural network model in order to predict biodiesel yield. The main goal of this study was to assess how accurately this artificial neural network model to predict biodiesel yield conducted under supercritical MTBE condition. The result shows that artificial neural network is a powerful tool for modeling and predicting biodiesel yield conducted under supercritical MTBE condition that was proven by a high value of coefficient of determination (R of 0.9969, 0.9899, and 0.9658 for training, validation, and testing, respectively. Using this approach, the highest biodiesel yield was determined of 0.93 mol/mol (corresponding to the actual biodiesel yield of 0.94 mol/mol that was achieved at 400 °C, under the reactor pressure of 10 MPa, oil-to-MTBE molar ratio of 1:40 within 15 min of reaction time.

  8. Biomarkers of exposure to aromatic hydrocarbons and methyl tert-butyl ether in petrol station workers.

    Science.gov (United States)

    De Palma, Giuseppe; Poli, Diana; Manini, Paola; Andreoli, Roberta; Mozzoni, Paola; Apostoli, Pietro; Mutti, Antonio

    2012-06-01

    This cross-sectional study was aimed at reconstructing the exposure to gasoline in 102 petrol station attendants by environmental and biological monitoring of benzene, toluene, ethylbenzene and xylene (BTEX) and biomonitoring of methyl tert-butyl ether (MTBE). Airborne BTEX were higher for manual refuelers than self-service assistants and were highly correlated with each other. Significant relationships were found between airborne BTX and the corresponding urinary solvents (U-BTX) and beween airborne B and urinary MTBE (U-MTBE). Smokers eliminated higher values of U-B, trans,trans-muconic (t,t-MA) and S-phenylmercapturic (S-PMA) acids but not U-MTBE. All these biomarkers were, however, significantly raised during the shift, independently from smoking. Linear regression confirmed that occupational exposure was a main predictor of U-MTBE, U-B and S-PMA values, both the latter confounded by smoking habits. The study supports the usefulness of biomonitoring even at low exposure levels.

  9. Biofiltration of methyl tert-butyl ether vapors by cometabolism with pentane: modeling and experimental approach.

    Science.gov (United States)

    Dupasquier, David; Revah, Sergio; Auria, Richard

    2002-01-15

    Degradation of methyl tert-butyl ether (MTBE) vapors by cometabolism with pentane using a culture of pentane-oxidizing bacteria (Pseudomonas aeruginosa) was studied in a 2.4-L biofilter packed with vermiculite, an inert mineral support. Experimental pentane elimination capacity (EC) of approximately 12 g m(-3) h(-1) was obtained for an empty bed residence time (EBRT) of 1.1 h and inlet concentration of 18.6 g m(-3). For these experimental conditions, EC of MTBE between 0.3 and 1.8 g m(-3) h(-1) were measured with inlet MTBE concentration ranging from 1.1 to 12.3 g m(-3). The process was modeled with general mass balance equations that consider a kinetic model describing cross-competitive inhibition between MTBE (cosubstrate) and pentane (substrate). The experimental data of pentane and MTBE removal efficiencies were compared to the theoretical predictions of the model. The predicted pentane and MTBE concentration profiles agreed with the experimental data for steady-state operation. Inhibition by MTBE of the pentane EC was demonstrated. Increasing the inlet pentane concentration improved the EC of MTBE but did not significantly change the EC of pentane. MTBE degradation rates obtained in this study were much lower than those using consortia or pure strains that can mineralize MTBE. Nevertheless, the system can be improved by increasing the active biomass.

  10. Biodegradation of methyl tert-butyl ether and other fuel oxygenates by a new strain, Mycobacterium austroafricanum IFP 2012.

    Science.gov (United States)

    François, Alan; Mathis, Hugues; Godefroy, Davy; Piveteau, Pascal; Fayolle, Françoise; Monot, Frédéric

    2002-06-01

    A strain that efficiently degraded methyl tert-butyl ether (MTBE) was obtained by initial selection on the recalcitrant compound tert-butyl alcohol (TBA). This strain, a gram-positive methylotrophic bacterium identified as Mycobacterium austroafricanum IFP 2012, was also able to degrade tert-amyl methyl ether and tert-amyl alcohol. Ethyl tert-butyl ether was weakly degraded. tert-Butyl formate and 2-hydroxy isobutyrate (HIBA), two intermediates in the MTBE catabolism pathway, were detected during growth on MTBE. A positive effect of Co2+ during growth of M. austroafricanum IFP 2012 on HIBA was demonstrated. The specific rate of MTBE degradation was 0.6 mmol/h/g (dry weight) of cells, and the biomass yield on MTBE was 0.44 g (dry weight) per g of MTBE. MTBE, TBA, and HIBA degradation activities were induced by MTBE and TBA, and TBA was a good inducer. Involvement of at least one monooxygenase during degradation of MTBE and TBA was shown by (i) the requirement for oxygen, (ii) the production of propylene epoxide from propylene by MTBE- or TBA- grown cells, and (iii) the inhibition of MTBE or TBA degradation and of propylene epoxide production by acetylene. No cytochrome P-450 was detected in MTBE- or TBA-grown cells. Similar protein profiles were obtained after sodium dodecyl sulfate-polyacrylamide gel electrophoresis of crude extracts from MTBE- and TBA-grown cells. Among the polypeptides induced by these substrates, two polypeptides (66 and 27 kDa) exhibited strong similarities with known oxidoreductases.

  11. Aerobic degradation of methyl tert-butyl ether by a Proteobacteria strain in a closed culture system

    Institute of Scientific and Technical Information of China (English)

    ZHONG Wei-hong; CHEN Jian-meng; LU Zheng; CHEN Dong-zhi; CHEN Xiao

    2007-01-01

    The contamination of methyl tert-butyl ether (MTBE) in underground waters has become a widely concerned problem all over the world. In this study, a novel closed culture system with oxygen supplied by H2O2 was introduced for MTBE aerobic biodegradation. After 7 d, almost all MTBE was degraded by a pure culture, a member of β-Proteobacteria named as PM1, in a closed system with oxygen supply, while only 40% MTBE was degraded in one without oxygen supply. Dissolved oxygen (DO) levels of the broth in closed systems respectively with and without H2O2 were about 5-6 and 4 mg/L. Higher DO may improve the activity of monooxygemase, which is the key enzyme of metabolic pathway from MTBE to tert-butyl alcohol and finally to CO2, and may result in the increase of the degrading activity of PM1 cell. The purge and trap GC-MS result of the broth in closed systems showed that tert-butyl alcohol,isopronol and acetone were the main intermediate products.

  12. Urinary methyl tert-butyl ether and benzene as biomarkers of exposure to urban traffic.

    Science.gov (United States)

    Campo, Laura; Cattaneo, Andrea; Consonni, Dario; Scibetta, Licia; Costamagna, Paolo; Cavallo, Domenico M; Bertazzi, Pier Alberto; Fustinoni, Silvia

    2011-02-01

    Methyl tert-butyl ether (MTBE) and benzene are added to gasoline to improve the combustion process and are found in the urban environment as a consequence of vehicular traffic. Herein we evaluate urinary MTBE (MTBE-U) and benzene (BEN-U) as biomarkers of exposure to urban traffic. Milan urban policemen (130 total) were investigated in May, July, October, and December for a total of 171 work shifts. Personal exposure to airborne benzene and carbon monoxide (CO), and atmospheric data, were measured during the work shift, while personal characteristics were collected by a questionnaire. A time/activity diary was completed by each subject during the work shift. Spot urine samples were obtained for the determination of MTBE-U and BEN-U. Median personal exposure to CO and airborne benzene were 3.3 mg/m(3) and 9.6 μg/m(3), respectively; median urinary levels in end-of-shift (ES) samples were 147 ng/L (MTBE-U) and 207 ng/L (BEN-U). The time spent on traffic duty at crossing was about 40% of work time. Multiple linear regression models, taking into account within-subject correlations, were applied to investigate the role of urban pollution, atmospheric conditions, job variables and personal characteristics on the level of biomarkers. MTBE-U was influenced by the month of sampling and positively correlated to the time spent in traffic guarding, CO exposure and atmospheric pressure, while negatively correlated to wind speed (R(2) for total model 0.63, P<0.001). BEN-U was influenced by the month and smoking habit, and positively correlated to urinary creatinine; moreover, an interaction between CO and smoking was found (R(2)=0.62, P<0.001). These results suggest that MTBE-U is a reliable marker for assessing urban traffic exposure, while BEN-U is determined mainly by personal characteristics.

  13. LIDEM unit for the production of methyl tert-butyl ether from butanes

    Energy Technology Data Exchange (ETDEWEB)

    Rudin, M.G.; Zadvornov, M.A.

    1994-09-01

    One of the basic problems in the production of motor fuels is how to obtain high-octane unleaded gasolines that will meet today`s ecological requirements. The term {open_quotes}reformulated gasolines{close_quotes} has come into general use throughout the world to denote fuels with a certain chemical composition. These gasolines consist of preselected components; as shown by worldwide experience, they must include oxygen-containing compounds that are distinguished by high octane numbers and low reactivities. Standards in effect in the United States, Japan, and certain Western European countries require that automotive gasolines must contain at least 2-4% by weight of oxygen-containing compounds (calculated as oxygen). In the last 15 years, in order to meet these requirements, production has been set up in various countries for the manufacture of high-octane oxygen-containing components known as oxygenates. The most common of these is methyl tert-butyl ether (MTBE), obtained by etherification of isobutene by methanol. Process technology developed by this last organization was used as the basis for constructing a unit in the Nizhnekamskneftekhim Production Association and at the Mazheikyai Petroleum Refinery in Lithuania. MTBE production has been held back mainly by a shortage of isobutene, which is obtained mainly from butane-butene cuts produced in cat crackers. In order to alleviate this shortage, it has been proposed that MTBE should be obtained from saturated C{sub 4} hydrocarbons that are recovered in processing oilfield associated gas, and also in the refinery from primary distillation units, catalytic reformers, and hydrocrackers. A working design was developed in 1991-1992 by Lengiproneftekhim for a basically new combination unit designed for the processing of saturated C{sub 4} hydrocarbons, which has been termed the LIDEM unit (Leningrad - isomerization - dehydrogenation - MTBE).

  14. Methyl tert-Butyl Ether (MTBE) in Ground Water, Air, and Precipitation at North Windham, Maine

    Science.gov (United States)

    Nielsen, Martha G.; Peckenham, John M.

    2000-01-01

    Thirty-one monitoring wells in the Windham aquifer in North Windham, Maine, were sampled for methyl tert-butyl ether (MTBE) from July 1998 to May 1999. MTBE was detected in 35 percent of the wells sampled in the Windham aquifer. MTBE was detected in 64 percent of wells in the high-yielding part of the aquifer; these wells account for 82 percent of all wells with detectable MTBE. Land cover also was found to be associated with MTBE in the wells in the study area, with the urban and low-density residential areas having more MTBE than undeveloped areas. The median concentration in wells with detectable MTBE was 1.13 micrograms per liter. Air and precipitation samples were collected in North Windham along with ground-water samples. Air samples were collected every 10 days from December 1998 to July 1999 (20 samples). MTBE was present in all 20 air samples collected, at concentrations ranging from 0.03 ppbv (parts per billion by volume) to 1.0 ppbv. Before Maine opted out of the reformulated gasoline (RFG) program in the spring of 1999, median concentrations in air at the North Windham site were 0.25 ppbv. After Maine stopped using RFG, the median concentration in air dropped to 0.09 ppbv. No MTBE was detected in four samples of precipitation at North Windham. The lack of rainfall during the study period prevented the collection of an adequate number of samples, and technical difficulties negated the results of some of the analyses of the samples that were collected. Based on the equilibrium partitioning of MTBE from the air into rain, the hypothetical average concentration of MTBE in rainfall during months when recharge typically occurs (March-April and October-December) would be approximately 0.3 to 0.4 micrograms per liter during the time that RFG was being used in Maine. After the phaseout of RFG, the maximum average concentration of MTBE in rainfall during these months would be approximately 0.1 micrograms per liter. The distribution and concentrations of MTBE that

  15. Vapor intrusion risk of fuel ether oxygenates methyl tert-butyl ether (MTBE), tert-amyl methyl ether (TAME) and ethyl tert-butyl ether (ETBE): A modeling study.

    Science.gov (United States)

    Ma, Jie; Xiong, Desen; Li, Haiyan; Ding, Yi; Xia, Xiangcheng; Yang, Yongqi

    2017-06-15

    Vapor intrusion of synthetic fuel additives represents a critical yet still neglected problem at sites contaminated by petroleum fuel releases. This study used an advanced numerical model to investigate the vapor intrusion potential of fuel ether oxygenates methyl tert-butyl ether (MTBE), tert-amyl methyl ether (TAME), and ethyl tert-butyl ether (ETBE). Simulated indoor air concentration of these compounds can exceed USEPA indoor air screening level for MTBE (110μg/m(3)). Our results also reveal that MTBE has much higher chance to cause vapor intrusion problems than TAME and ETBE. This study supports the statements made by USEPA in the Petroleum Vapor Intrusion (PVI) Guidance that the vertical screening criteria for petroleum hydrocarbons may not provide sufficient protectiveness for fuel additives, and ether oxygenates in particular. In addition to adverse impacts on human health, ether oxygenate vapor intrusion may also cause aesthetic problems (i.e., odour and flavour). Overall, this study points out that ether oxygenates can cause vapor intrusion problems. We recommend that USEPA consider including the field measurement data of synthetic fuel additives in the existing PVI database and possibly revising the PVI Guidance as necessary.

  16. Determination of low level methyl tert-butyl ether, ethyl tert-butyl ether and methyl tert-amyl ether in human urine by HS-SPME gas chromatography/mass spectrometry.

    Science.gov (United States)

    Scibetta, Licia; Campo, Laura; Mercadante, Rosa; Foà, Vito; Fustinoni, Silvia

    2007-01-02

    Methyl tert-butyl ether (MTBE), ethyl tert-butyl ether (ETBE) and tert-amyl methyl ether (TAME) are oxygenated compounds added to gasoline to enhance octane rating and to improve combustion. They may be found as pollutants of living and working environments. In this work a robotized method for the quantification of low level MTBE, ETBE and TAME in human urine was developed and validated. The analytes were sampled in the headspace of urine by SPME in the presence of MTBE-d12 as internal standard. Different fibers were compared for their linearity and extraction efficiency: carboxen/polydimethylsiloxane, polydimethylsiloxane/divinylbenzene, and polydimethylsiloxane. The first, although highly efficient, was discarded due to deviation of linearity for competitive displacement, and the polydimethylsiloxane/divinylbenzene fiber was chosen instead. The analysis was performed by GC/MS operating in the electron impact mode. The method is very specific, with range of linearity 30-4600 ng L(-1), within- and between-run precision, as coefficient of variation, ethers was evaluated analysing the specimens of seven traffic policemen exposed to autovehicular emissions: using the calibration curve and the method of standard additions comparable levels of MTBE (68-528 ng L(-1)), ETBE (<6 ng L(-1)), and TAME (<6 ng L(-1)) were obtained.

  17. Single-walled carbon nanotubes as an effective adsorbent in solid-phase microextraction of low level methyl tert-butyl ether, ethyl tert-butyl ether and methyl tert-amyl ether from human urine.

    Science.gov (United States)

    Rastkari, Noushin; Ahmadkhaniha, Reza; Yunesian, Masud

    2009-05-15

    Carbon nanotubes (CNTs) are a kind of new carbon-based nano-materials which have drawn great attention in many application fields. The potential single-walled carbon nanotubes (SWCNTs) as solid-phase microextraction (SPME) adsorbents for the preconcentration of environmental pollutants have been investigated in recent years. The goal of this work was to investigate the feasibility of SWCNTs used as adsorbents for solid-phase microextraction of methyl tert-butyl ether (MTBE), ethyl tert-butyl ether (ETBE) and tert-amyl methyl ether (TAME) in human urine. SWCNTs were attached onto a stainless steel wire through organic binder. Potential factors affecting the extraction efficiency were optimized, including extraction time, extraction temperature, desorption time, desorption temperature, and salinity. The developed method showed good performance according to the ICH performance criteria for bioanalytical methods. The calibration curves of the ethers were linear (r(2)>or=0.992) in the range from 10 to 5000 ng L(-1). The limits of detection at a signal-to-noise (S/N) ratio of 3 were 10 ng L(-1) for all the analytes. In addition, compared with the commercial carboxen/polydimethylsiloxane (CAR/PDMS) fiber, the SWCNT fiber showed better thermal stability (over 350 degrees C) and longer life span (over 150 times). The developed method was applied successfully to determine trace level of the ethers in urine of 10 healthy male volunteers.

  18. Biodegradation of methyl tert-butyl ether by cometabolism with hexane in biofilters inoculated with Pseudomonas aeruginosa.

    Science.gov (United States)

    Salazar, Margarita; Morales, Marcia; Revah, Sergio

    2012-01-01

    Biodegradation of methyl tert-butyl ether (MTBE) vapors by cometabolism with gaseous hexane (n-hexane > 95%) was investigated using Pseudomonas aeruginosa utilizing short chain aliphatic hydrocarbon (C(5)-C(8)). Kinetic batch experiments showed that MTBE was degraded even when hexane was completely exhausted with a cometabolic coefficient of 1.06 ± 0.16 mg MTBE mg hexane(-1). Intermediate tert-butyl alcohol (TBA) accumulation was observed followed by its gradual consumption. A maximum MTBE elimination capacity (EC(MAX)) of 35 g m(-3) h(-1) and removal efficiency (RE) of 70% were attained in mineral medium amended biofilters having an empty bed residence time (EBRT) of 1 min. For these experimental conditions, a maximum hexane EC of approximately 60 g m(-3) h(-1) was obtained at a load of 75 g m(-3) h(-1). Experiments under transient conditions revealed a competitive substrate interaction between MTBE and hexane. Biomass densities between 5.8 and 12.6 g L(biofilter) (-1) were obtained. Nevertheless, production of biopolymers caused non-uniform distribution flow rates that reduced the performance. Residence time distribution profiles showed an intermediate dispersion flow rate with a dispersion coefficient of 0.8 cm(2) s(-1).

  19. Enhanced cometabolic degradation of methyl tert-butyl ether by a Pseudomonas sp. strain grown on n-pentane

    Science.gov (United States)

    Li, S. S.; Wang, S.; Yan, W.

    2016-08-01

    When methyl tert-butyl ether (MTBE) is added as oxygenates it increases the octane number and decreases the release of nitric oxide from the incomplete combustion of reformulated gasoline. The extensive use of MTBE allowed it to be detectable as a pollutant in both ground-level and underground water worldwide. The present study focuses on the isolation and characterization of MTB-degrading microorganisms by cometabolism based on the results of growth on different carbon sources. It also focuses on the kinetic analysis and the continuous degradation of MTBE. A bacterial strain WL1 that can grow on both n-alkanes (C5-C8) and aromatics was isolated and named Pseudomonas sp. WL1 according to the 16S rDNA sequencing analysis. Strain WL1 could cometabolically degrade MTBE in the presence of n-alkanes with a desirable degradation rate. Diverse n-alkanes with different lengths of carbon chains showed significant influence on the degradation rate of MTBE and accumulation of tert-butyl alcohol (TBA). When strain WL1 cometabolically degraded MTBE in the presence of n-pentane, higher MTBE-degrading rate and lower TBA-accumulation were observed (Vmax = 38.1 nmol/min/mgprotei, Ks = 6.8 mmol/L). In the continuous degrading experiment, the removal efficiency of MTBE by Pseudomonas sp. WL1 did not show any obvious decrease after five subsequent additions.

  20. Determination of low level methyl tert-butyl ether, ethyl tert-butyl ether and methyl tert-amyl ether in human urine by HS-SPME gas chromatography/mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Scibetta, Licia [Department of Occupational and Environmental Medicine, University of Milano and Fondazione IRCCS Ospedale Maggiore Policlinico, Mangiagalli e Regina Elena, Via S. Barnaba, 8-20122 Milan (Italy); Campo, Laura [Department of Occupational and Environmental Medicine, University of Milano and Fondazione IRCCS Ospedale Maggiore Policlinico, Mangiagalli e Regina Elena, Via S. Barnaba, 8-20122 Milan (Italy); Mercadante, Rosa [Department of Occupational and Environmental Medicine, University of Milano and Fondazione IRCCS Ospedale Maggiore Policlinico, Mangiagalli e Regina Elena, Via S. Barnaba, 8-20122 Milan (Italy); Foa, Vito [Department of Occupational and Environmental Medicine, University of Milano and Fondazione IRCCS Ospedale Maggiore Policlinico, Mangiagalli e Regina Elena, Via S. Barnaba, 8-20122 Milan (Italy); Fustinoni, Silvia [Department of Occupational and Environmental Medicine, University of Milano and Fondazione IRCCS Ospedale Maggiore Policlinico, Mangiagalli e Regina Elena, Via S. Barnaba, 8-20122 Milan (Italy)]. E-mail: silvia.fustinoni@unimi.it

    2007-01-02

    Methyl tert-butyl ether (MTBE), ethyl tert-butyl ether (ETBE) and tert-amyl methyl ether (TAME) are oxygenated compounds added to gasoline to enhance octane rating and to improve combustion. They may be found as pollutants of living and working environments. In this work a robotized method for the quantification of low level MTBE, ETBE and TAME in human urine was developed and validated. The analytes were sampled in the headspace of urine by SPME in the presence of MTBE-d12 as internal standard. Different fibers were compared for their linearity and extraction efficiency: carboxen/polydimethylsiloxane, polydimethylsiloxane/divinylbenzene, and polydimethylsiloxane. The first, although highly efficient, was discarded due to deviation of linearity for competitive displacement, and the polydimethylsiloxane/divinylbenzene fiber was chosen instead. The analysis was performed by GC/MS operating in the electron impact mode. The method is very specific, with range of linearity 30-4600 ng L{sup -1}, within- and between-run precision, as coefficient of variation, <22 and <16%, accuracy within 20% the theoretical level, and limit of detection of 6 ng L{sup -1} for all the analytes. The influence of the matrix on the quantification of these ethers was evaluated analysing the specimens of seven traffic policemen exposed to autovehicular emissions: using the calibration curve and the method of standard additions comparable levels of MTBE (68-528 ng L{sup -1}), ETBE (<6 ng L{sup -1}), and TAME (<6 ng L{sup -1}) were obtained.

  1. Lung toxicity and tumor promotion by hydroxylated derivatives of 2,6-di-tert-butyl-4-methylphenol (BHT) and 2-tert-butyl-4-methyl-6-iso-propylphenol: correlation with quinone methide reactivity.

    Science.gov (United States)

    Kupfer, Rene; Dwyer-Nield, Lori D; Malkinson, Alvin M; Thompson, John A

    2002-08-01

    Acute pulmonary toxicity and tumor promotion by the food additive 2,6-di-tert-butyl-4-methylphenol (BHT) in mice are well documented. These effects have been attributed to either of two quinone methides, 2,6-di-tert-butyl-4-methylenecyclohexa-2,5-dienone (BHT-QM) formed through direct oxidation of BHT by pulmonary cytochrome P450 or a quinone methide formed by hydroxylation of a tert-butyl group of BHT (to form BHTOH) followed by oxidation of this metabolite to BHTOH-QM. BHTOH-QM is a more reactive electrophile compared to BHT-QM due to intramolecular interactions of the side-chain hydroxyl with the carbonyl oxygen. To further examine this bioactivation pathway, an analogue of BHTOH was prepared, 2-tert-butyl-6-(1'-hydroxy-1'-methyl)ethyl-4-methylphenol (BPPOH), that is structurally very similar to BHTOH but forms a quinone methide (BPPOH-QM) capable of more efficient intramolecular hydrogen bonding and, therefore, higher electrophilicity than BHTOH-QM. BPPOH-QM was synthesized and its reactivity with water, methanol, and glutathione determined to be >10-fold higher than that of BHTOH-QM. The conversions of BPPOH and BHTOH to quinone methides in lung microsomes from male BALB/cByJ mice were quantitatively similar, but in vivo the former was pneumotoxic at one-half of the dose required for the latter and one-eighth of the dose required for BHT, as determined by increased lung weight:body weight ratios following a single i.p. injection. Similar differences were found in the doses of BHT, BHTOH, or BPPOH required for tumor promotion after a single initiating dose of 3-methylcholanthrene followed by three weekly injections of the phenol. The downregulaton of calpain II, previously shown to accompany lung tumor promotion by BHT and BHTOH, also occurred with BPPOH. The correlation between biologic activities of these phenols and the reactivities of their corresponding quinone methides provides additional support for the role of BHTOH-QM as the principal metabolite

  2. Microbial degradation and fate in the environment of methyl tert-butyl ether and related fuel oxygenates.

    Science.gov (United States)

    Fayolle, F; Vandecasteele, J P; Monot, F

    2001-08-01

    Oxygenates, mainly methyl tert-butyl ether (MTBE), are commonly added to gasoline to enhance octane index and improve combustion efficiency. Other oxygenates used as gasoline additives are ethers such as ethyl tert-butyl ether (ETBE), tert-amyl methyl ether (TAME), and alcohols such as tert-butyl alcohol (TBA). As a result of its wide use, MTBE has been detected, mainly in the USA, in groundwater and surface waters, and is a cause of concern because of its possible health effects and other undesirable consequences. MTBE is a water-soluble and mobile compound that generates long pollution plumes in aquifers impacted by gasoline releases from leaking tanks. Field observations concur in estimating that, because of recalcitrance to biodegradation, natural attenuation is slow (half-life of at least 2 years). However, quite significant advances have been made in recent years concerning the microbiology of the degradation of MTBE and other oxygenated gasoline additives. The recalcitrance of these compounds results from the presence in their structure of an ether bond and of a tertiary carbon structure. For the most part, only aerobic microbial degradation systems have been reported so far. Consortia capable of mineralizing MTBE have been selected. Multiple instances of the cometabolism of MTBE with pure strains or with microflorae, growing on n-alkanes, isoalkanes, cyclohexane or ethers (diethyl ether, ETBE), have been described. MTBE was converted into TBA in all cases and was sometimes further degraded, but it was not used as a carbon source by the pure strains. However, mineralization of MTBE and TBA by several pure bacterial strains using these compounds as sole carbon and energy source has recently been reported. The pathways of metabolism of MTBE involve the initial attack by a monooxygenase. In several cases, the enzyme was characterized as a cytochrome P-450. After oxygenation, the release of a C -unit as formaldehyde or formate leads to the production of TBA

  3. Energy analysis for the production of biodiesel in a spiral reactor using supercritical tert-butyl methyl ether (MTBE).

    Science.gov (United States)

    Farobie, Obie; Matsumura, Yukihiko

    2015-11-01

    In this study, energy analysis was conducted for the production of biodiesel in a spiral reactor using supercritical tert-butyl methyl ether (MTBE). This study aims to determine the net energy ratio (NER) and energy efficiency for the production of biodiesel using supercritical MTBE and to verify the effectiveness of the spiral reactor in terms of heat recovery efficiency. The analysis results revealed that the NER for this process was 0.92. Meanwhile, the energy efficiency was 0.98, indicating that the production of biodiesel in a spiral reactor using supercritical MTBE is an energy-efficient process. By comparing the energy supply required for biodiesel production between spiral and conventional reactors, the spiral reactor was more efficient than the conventional reactor.

  4. A comparative study of biodiesel production using methanol, ethanol, and tert-butyl methyl ether (MTBE) under supercritical conditions.

    Science.gov (United States)

    Farobie, Obie; Matsumura, Yukihiko

    2015-09-01

    In this study, biodiesel production under supercritical conditions among methanol, ethanol, and tert-butyl methyl ether (MTBE) was compared in order to elucidate the differences in their reaction behavior. A continuous reactor was employed, and experiments were conducted at various reaction temperatures (270-400 °C) and reaction times (3-30 min) and at a fixed pressure of 20 MPa and an oil-to-reactant molar ratio of 1:40. The results showed that under the same reaction conditions, the supercritical methanol method provided the highest yield of biodiesel. At 350 °C and 20 MPa, canola oil was completely converted to biodiesel after 10, 30, and 30 min in the case of - supercritical methanol, ethanol, and MTBE, respectively. The reaction kinetics of biodiesel production was also compared for supercritical methanol, ethanol, and MTBE.

  5. ETBE (ethyl tert butyl ether) and TAME (tert amyl methyl ether) affect microbial community structure and function in soils.

    Science.gov (United States)

    Bartling, Johanna; Esperschütz, Jürgen; Wilke, Berndt-Michael; Schloter, Michael

    2011-03-15

    Ethyl tert butyl ether (ETBE) and tert amyl methyl ether (TAME) are oxygenates used in gasoline in order to reduce emissions from vehicles. The present study investigated their impact on a soil microflora that never was exposed to any contamination before. Therefore, soil was artificially contaminated and incubated over 6 weeks. Substrate induced respiration (SIR) measurements and phospholipid fatty acid (PLFA) analysis indicated shifts in both, microbial function and structure during incubation. The results showed an activation of microbial respiration in the presence of ETBE and TAME, suggesting biodegradation by the microflora. Furthermore, PLFA concentrations decreased in the presence of ETBE and TAME and Gram-positive bacteria became more dominant in the microbial community.

  6. Biological Activity of Methyl tert-butyl Ether in Relation to Soil Microorganisms has a Negative Environmental Impact

    Directory of Open Access Journals (Sweden)

    Gholam H.S. Bonjar

    2005-01-01

    Full Text Available Fuel oxygenates are added to gasoline to enhance combustion efficiency of automobiles and reduce air pollution. Methyl tert-butyl ether (MTBE is the most commonly used oxygenate because of its low cost, high-octane level and ease of blending with gasoline. However, due to its water solubility, high mobility and low biodegradability it leaches in soil subsurface at the speed of groundwater. Amending gasoline with MTBE has made a widespread contamination of groundwater, surface waters in coastal environments and at low levels in well water. Although current public concern about MTBE contamination is widely discussed, but its adverse effects on soil micro flora is not yet understood. Soil Streptomycetes are beneficial to soil productivity and are of the major contributors to the biological buffering of soils having antagonistic activity against wide spectrum of pathogenic bacteria and fungi. Streptomyceticidal activity of Methyl tert-butyl ether (MTBE is being reported here. Adverse effect of MTBE against four soil-inhabitant Streptomyces spp. isolates and two plant root-pathogens was investigated. To elucidate antimicrobial activity of MTBE, it was tested against four soil isolates of Streptomyces; a plant bacterial-pathogen, Erwinia carotovora and a plant root fungal-pathogen, Fusarium solani. MTBE did not reveal any growth inhibitory-activity against E. carotovora and F. solani but showed strong inhibitory effect against Streptomyces spp. isolates. The Minimum Inhibitory Concentration (MIC was 1/800 of the original MTBE. Fuel leaks and spills can adversely suppress or eliminate the Streptomyces role in the soil causing alteration in the balance of soil micro flora. This change will lead to domination of microorganisms with adverse biological or ecological effects. Fortunately, major oil companies have decided to phase out MTBE from automobile fuels because of its adverse effect on environment and human health.

  7. Catabolism of methyl ter-butyl ether (MTBE): characterization of the enzymes of Mycobacterium austroafricanum IFP 2012 involved in MTBE degradation; Catabolisme du methyl tert-butyl ether (MTBE): caracterisation des enzymes impliquees dans la degradation du MTBE chez Mycobacterium austroafricanum IFP 2012

    Energy Technology Data Exchange (ETDEWEB)

    Lopes Ferreira, N.

    2005-11-15

    Methyl tert-butyl ether (MTBE) is added to gasoline to meet the octane index requirement. its solubility in water and its poor biodegradability made the use of MTBE a great environmental concern, particularly regarding aquifers. We previously isolated M austroafricanum IFP 2012 able to use MTBE as a sole source of carbon and energy and the MTBE pathway was partially characterized. In the present study, which aimed at isolating the genes involved in MTBE biodegradation in order to use them for estimation of MTBE biodegradation capacities in contaminated environment, we isolated a new M. austroafricanum strain, IFP 2015. A new degradation intermediate, the 2-methyl 1,2-propane-diol (2-M1,2-PD), the product of tert-butanol (TBA) oxidation, was identified. We also determined the enzymes induced during growth of M. austroafricanum IFP 2012 on MTBF. Then, using the tools of protein analysis and of molecular biology, we isolated and cloned the mpd genes cluster in the plasmid pCL4D. Heterologous expression of the recombinant plasmid in M smegmatis tmc2 155, showed the involvement of an 2-M1,2-PD dehydrogenase (MpdB) and a hydroxy-iso-butyr-aldehyde dehydrogenase (MpdC), encoded by mpdB and mpdC, respectively. Both enzymes were responsible for the conversion of 2-M 1,2-PD to hydroxy-isobutyric acid (HIBA). A further survey of different M austroafricanum strains, including IFP 2012, IFP 2015 and JOBS (ex-M vaccae) showed the link between the ability to grow on C{sub 2} to C{sub 16} n-alkanes and the MTBE and TBA degradation capacities. The alkB gene was partially sequenced in all these strains. Expression of alkB was demonstrated in M. austroafricanum IFP 2012 after growth on propane, hexane, hexadecane and TBA. Finally, we identified 2-propanol as the intermediate of HIBA degradation. The gene encoding the 2-propanol:p-N,N'-dimethyl-4-nitroso-aniline (NDMA) oxidoreductase was detected M austroafricanum IFP 2012. (author)

  8. Distribution of methyl tert-butyl ether (MTBE) and selected water-quality constituents in the surficial aquifer at the Dover National Test Site, Dover Air Force Base, Delaware, 2001

    Science.gov (United States)

    Stewart, Marie; Guertal, William R.; Barbaro, Jeffrey R.; McHale, Timothy J.

    2004-01-01

    A joint study by the Dover National Test Site, Dover Air Force Base, Delaware, and the U.S. Geological Survey was conducted from June 27 through July 18, 2001, to determine the spatial distribution of the gasoline oxygenate additive methyl tert-butyl ether and selected water-quality constituents in the surficial aquifer underlying the Dover National Test Site. This report provides a summary assessment of the distribution of methyl tert-butyl ether and a preliminary screening of selected constituents that may affect natural attenuation and remediation demonstrations at the Dover National Test Site. The information gathered during this study is designed to assist potential remedial investigators who are considering conducting a methyl tert-butyl ether remedial demonstration at the test site. In addition, the study supported a planned enhanced bioremediation demonstration and assisted the Dover National Test Site in identifying possible locations for future methyl tert-butyl ether remediation demonstrations. A direct-push drill rig was used to collect a total of 147 ground-water samples (115 VOC samples and 32 quality-assurance samples) at varying depths. Volatile organic compounds were above the method reporting limits in 59 of the 115 ground-water samples. The concentrations ranged from below detection limits to maximum values of 12.4 micrograms per liter of cis-1,2-dichloro-ethene, 1.14 micrograms per liter of trichloro-ethene, 2.65 micrograms per liter of tetrachloro-ethene, 1,070 micrograms per liter of methyl tert-butyl ether, 4.36 micrograms per liter of benzene, and 1.8 micrograms per liter of toluene. Vinyl chloride, ethylbenzene, p,m-xylene, and o-xylene were not detected in any of the samples collected during this investigation. Methyl tert-butyl ether was detected in 47 of the 115 ground-water samples. The highest concentrations of methyl tert-butyl ether were detected in the surficial aquifer from ?4.6 to 6.4 feet mean sea level; however, methyl tert-butyl

  9. The efficient photocatalytic degradation of methyl tert-butyl ether under Pd/ZnO and visible light irradiation.

    Science.gov (United States)

    Seddigi, Zaki S; Ahmed, Saleh A; Bumajdad, Ali; Danish, Ekram Y; Shawky, Ahmed M; Gondal, Mohammed A; Soylak, Mustafa

    2015-01-01

    Methyl tert-butyl ether is a commonly used fuel oxygenate that is present in gasoline. It was introduced to eliminate the use of leaded gasoline and to improve the octane quality because it aids in the complete combustion of fuel by supplying oxygen during the combustion process. Over the past decade, the use of MTBE has increased tremendously worldwide. For obvious reasons relating to accidental spillage, MTBE started to appear as an environmental and human health threat because of its nonbiodegradable nature and carcinogenic potential, respectively. In this work, MTBE was degraded with the help of an advanced oxidation process through the use of zinc oxide as a photocatalyst in the presence of visible light. A mixture of 200 mg of zinc oxide in 350 mL of 50 ppm MTBE aqueous solution was irradiated with visible light for a given time. The complete degradation of MTBE was recorded, and approximately 99% photocatalytic degradation of 100 ppm MTBE solution was observed. Additionally, the photoactivity of 1% Pd-doped ZnO was tested under similar conditions to understand the effect of Pd doping on ZnO. Our results obtained under visible light irradiation are very promising, and they could be further explored for the degradation of several nondegradable environmental pollutants.

  10. Continuous on-line determination of methyl tert-butyl ether in water samples using ion mobility spectrometry.

    Science.gov (United States)

    Borsdorf, H; Rämmler, A

    2005-04-22

    A rapid analytical procedure for the on-line determination of methyl tert-butyl ether (MTBE) in water samples was developed. A new membrane extraction unit was used to extract the MTBE from water samples. The concentration of MTBE was determined using ion mobility spectrometry with 63Ni ionization and corona discharge ionization without chromatographic separation. Both ionization methods permit the sensitive determination of MTBE. A detection limit of 100 microg/L was established for the on-line procedure. Neither the inorganic compounds, humic substances nor gasoline were found to exert a significant influence on the peak intensity of the MTBE. The screening procedure can be used for concentrations of monoaromatic compounds (benzene, toluene, xylene) up to 600 microg/L. No sample preparation is required and the analysis results are available within 5 min. In order to determine concentrations between 10 microg/L and 100 microg/L, a discontinuous procedure was developed on the basis of the same experimental set-up.

  11. Methyl tert-butyl ether (MTBE) in public and private wells in New Hampshire: Occurrence, factors, and possible implications

    Science.gov (United States)

    Ayotte, J.D.; Argue, D.M.; McGarry, F.J.; Degnan, J.R.; Hayes, L.; Flanagan, S.M.; Helsel, D.R.

    2008-01-01

    Methyl tert-butyl ether (MTBE) concentrations ???0.2 ??g/L were found in samples of untreated water in 18% of public-supply wells (n = 284) and 9.1% of private domestic wells (n = 264) sampled in 2005 and 2006 in New Hampshire. In counties that used reformulated gasoline (RFG), MTBE occurred at or above 0.2 ??g/L in 30% of public- and 17% of private-supply wells. Additionally, 52% of public-supply wells collocated with fuel storage and 71% of mobile home park wells had MTBE. MTBE occurrence in public-supply wells was predicted by factors such as proximity to sources of fuel, land use, and population density, as well as low pH and distance from mapped lineaments. RFG use, land-use variables, and pH were important predictors of private-well MTBE occurrence. Variables representing sources of MTBE, such as the distance to known fuel sources, were not significant predictors of MTBE occurrence in private-supply wells. It is hypothesized that private wells may become contaminated from the collective effects of sources in high population areas and from undocumented incidental releases from onsite or proximal gasoline use. From 2003 to 2005, MTBE occurrence decreased in 63 public-supply wells and increased in 60 private-supply wells, but neither trend was statistically significant. ?? 2008 American Chemical Society.

  12. 2D-Cell Experiment on Methyl Tert-Butyl Ether Transport in Saturated Zone of Groundwater

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    As an additive of gasoline, methyl tert-butyl ether (MTBE) has a higher solubility in water, which is about 20 times as high as that of benzene. This characteristic results in MTBE dissolving out of the gasoline into the soil and groundwater. Due to relative unique physicochemical behavior of MTBE it would be an ideal candidate for use in environmental forensic investigations. In order to study the transport and distribution of MTBE in saturated zone of ground water, a two-dimensional experimental cell was setup to simulate the real environment of the groundwater flow.The effects of soil and groundwater flow velocity on the MTBE transport were investigated. The results show that the mobile distance of MTBE in vertical direction was smaller than that in horizontal direction paralleling with the groundwater flow. Because the main dynamics of groundwater flow direction was convection and dispersion, the movement of MTBE is also diffusion in the vertical direction. In addition, the transport of MTBE was more quick in high permeability porous media, and the increase of groundwater flow velocity can accelerate the MTBE plume development, but the irregularity and randomness of the plume are enhanced synchronously. These research results can give some helps for the investigation of MTBE movement in the groundwater, also can make some references for other petroleum contamination behavior.

  13. Determination of Methyl tert-Butyl Ether and tert-Butyl Alcohol in Water by Solid-Phase Microextraction/Head Space Analysis in Comparison to EPA Method 5030/8260B

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Keun-Chan; Stringfellow, William T.

    2003-10-02

    Methyl tert-butyl ether (MTBE) is now one of the most common groundwater contaminants in the United States. Groundwater contaminated with MTBE is also likely to be contaminated with tert-butyl alcohol (TBA), because TBA is a component of commercial grade MTBE, TBA can also be used as a fuel oxygenate, and TBA is a biodegradation product of MTBE. In California, MTBE is subject to reporting at concentrations greater than 3 {micro}g/L. TBA is classified as a ''contaminant of current interest'' and has a drinking water action level of 12 {micro}g/L. In this paper, we describe the development and optimization of a simple, automated solid phase microextraction (SPME) method for the analysis of MTBE and TBA in water and demonstrate the applicability of this method for monitoring MTBE and TBA contamination in groundwater, drinking water, and surface water. In this method, the headspace (HS) of a water sample is extracted with a carboxen/polydimethylsiloxane SPME fiber, the MTBE and TBA are desorbed into a gas chromatograph (GC), and detected using mass spectrometry (MS). The method is optimized for the routine analysis of MTBE and TBA with a level of quantitation of 0.3 {micro}g/L and 4 {micro}g/L, respectively, in water. MTBE quantitation was linear for over two orders of concentration (0.3 {micro}g/L -80 {micro}g/L). TBA was found to be linear within the range of 4 {micro}g/L-7,900 {micro}g/L. The lower level of detection for MTBE is 0.03 {micro}g/L using this method. This SPME method using headspace extraction was found to be advantageous over SPME methods requiring immersion of the fiber into the water samples, because it prolonged the life of the fiber by up to 400 sample analyses. This is the first time headspace extraction SPME has been shown to be applicable to the measurement of both MTBE and TBA at concentrations below regulatory action levels. This method was compared with the certified EPA Method 5030/8260B (purge-and-trap/GC/MS) using split

  14. Exposure to methyl tert-butyl ether, benzene, and total hydrocarbons at the Singapore-Malaysia causeway immigration checkpoint

    Energy Technology Data Exchange (ETDEWEB)

    Tan, C.; Ong, H.Y.; Kok, P.W. [and others

    1996-12-31

    The primary aim of this study was to determine the extent and levels of exposure to volatile organic compounds (VOCs) from automobile emissions in a group of immigration officers at a busy cross-border checkpoint. A majority (80%) of the workers monitored were exposed to benzene at levels between 0.01 and 0.5 ppm, with only 1.2% exceeding the current Occupational Safety and Health Administration occupational exposure limit of 1 ppm. The geometric mean (GM) concentrations of 8-hr time-weighted average exposure were 0.03 ppm, 0.9 ppm, and 2.46 ppm for methyl-tert-butyl ether (MTBE), benzene, and total hydrocarbons (THC), respectively. The highest time-weighted average concentrations measured were 1.05 ppm for MTBE, 2.01 ppm for benzene, and 34 ppm for THC. It was found that motorbikes emitted a more significant amount of pollutants compared with motor cars. On average, officers at the motorcycle booths were exposed to four to five times higher levels of VOCs (GMs of 0.07 ppm, 0.23 ppm, and 4.7 ppm for MTBE, benzene, and THC) than their counterparts at the motor car booths (GMs of 0.01 ppm, 0.05 ppm, and 1.5 ppm). The airborne concentrations of all three pollutants correlated with the flow of vehicle traffic. Close correlations were also noted for the concentrations in ambient air for the three pollutants measured. Benzene and MTBE had a correlation coefficient of 0.97. The overall findings showed that the concentrations of various VOCs were closely related to the traffic density, suggesting that they were from a common source, such as exhaust emissions from the vehicles. The results also indicated that although benzene, MTBE, and THC are known to be volatile, a significant amount could still be detected in the ambient environment, thus contributing to our exposure to these compounds. 4 refs., 6 figs.

  15. The interactions of methyl tert-butyl ether on high silica zeolites: a combined experimental and computational study.

    Science.gov (United States)

    Sacchetto, V; Gatti, G; Paul, G; Braschi, I; Berlier, G; Cossi, M; Marchese, L; Bagatin, R; Bisio, C

    2013-08-28

    In this work, the interactions of methyl tert-butyl ether (MTBE) on different dealuminated high silica zeolites were studied by means of both experimental and computational approaches. Zeolites with different textural and surface features were selected as adsorbents and the effect of their physico-chemical properties (i.e. pore size architecture and type and amount of surface OH sites) on sorption capacity were studied. High silica mordenite (MOR) and Y zeolites (both with a SiO2/Al2O3 ratio of 200) and ZSM-5 solid (SiO2/Al2O3 ratio of 500) were selected as model sorbents. By combining FTIR and SS-NMR (both (1)H and (13)C CPMAS NMR) spectroscopy it was possible to follow accurately the MTBE adsorption process on highly defective MOR characterized by a high concentration of surface SiOH groups. The adsorption process is found to occur in different steps and to involve isolated silanol sites, weakly interacting silanols, and the siloxane network of the zeolite, respectively. H-bonding and van der Waals interactions occurring between the mordenite surface and MTBE molecules were modeled by DFT calculations using a large cluster of the MOR structure where two adjacent side-pockets were fused in a large micropore to simulate a dealumination process leading to silanol groups. This is the locus where MTBE molecules are more strongly bound and stabilized. FTIR spectroscopy and gravimetric measurements allowed determination of the interaction strength and sorption capacities of all three zeolites. In the case of both Y and MOR zeolites, medium-weak H-bonding with isolated silanols (both on internal and external zeolite surfaces) and van der Waals interactions are responsible for MTBE adsorption, whereas ZSM-5, in which a negligible amount of surface silanol species is present, displays a much lower amount of adsorbed MTBE retained mainly through van der Waals interactions with zeolite siloxane network.

  16. An extractive membrane biofilm reactor as alternative technology for the treatment of methyl tert-butyl ether contaminated water.

    Science.gov (United States)

    Guisado, I M; Purswani, J; González-López, J; Pozo, C

    2016-09-01

    Among the strategies developed for contaminated groundwater bioremediation, those based on the use of bacteria adhering to inert supports and establishing biofilms have gained great importance in this field. Extractive membrane biofilm reactor (EMBFR) technology offers productive solutions for the removal of volatile and semi-volatile compounds. EMBFR technology is based on the use of extractive semipermeable membranes through which contaminants migrate to the biological compartment in which microorganisms with pollutant biotransformation and/or mineralization capacities can grow, forming an active biofilm on the membrane surface. The objective of this study was to assess the use of three bacterial strains (Paenibacillus sp. SH7 CECT 8558, Agrobacterium sp. MS2 CECT 8557, and Rhodococcus ruber EE6 CECT 8612), as inoculum in a lab-scale EMBFR running for 28 days under aerobic conditions to eliminate methyl tert-butyl ether (MTBE) from water samples. Three different hydraulic retention times (1, 6, and 12 h) were employed. MTBE degradation values were determined daily by a gas GC-MS technique, as well as suspended bacterial growth. The biofilm established by the bacterial strains on the semipermeable membrane was detected by Field-Emission Scanning Electron Microscopy (FESEM) at the end of each experiment. The acute toxicity of the treated effluents and biomedium was determined by Microtox(©) assay (EC50 ).The results achieved from the MTBE degradation, biofilm formation, and toxicity analysis indicated that bacterial strains MS2 and EE6 were the best options as selective inoculum, although further research is needed, particularly with regard to their possible use as a mixed culture. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:1238-1245, 2016. © 2016 American Institute of Chemical Engineers.

  17. Excess enthalpy, density, and speed of sound determination for the ternary mixture (methyl tert-butyl ether + 1-butanol + n-hexane)

    Energy Technology Data Exchange (ETDEWEB)

    Mascato, Eva [Departamento de Fisica Aplicada, Facultade de Ciencias, Universidade de Vigo, E-36310 Vigo (Spain); Mariano, Alejandra [Laboratorio de Fisicoquimica, Departamento de Quimica, Facultad de Ingenieria, Universidad Nacional del Comahue, 8300 Neuquen (Argentina); Pineiro, Manuel M. [Departamento de Fisica Aplicada, Facultade de Ciencias, Universidade de Vigo, E-36310 Vigo (Spain)], E-mail: mmpineiro@uvigo.es; Legido, Jose Luis [Departamento de Fisica Aplicada, Facultade de Ciencias, Universidade de Vigo, E-36310 Vigo (Spain); Paz Andrade, M.I. [Departamento de Fisica Aplicada, Facultade de Fisica, Universidade de Santiago de Compostela, E-15706 Santiago de Compostela (Spain)

    2007-09-15

    Density, ({rho}), and speed of sound, (u), from T = 288.15 to T = 308.15 K, and excess molar enthalpies, (h{sup E}) at T = 298.15 K, have been measured over the entire composition range for (methyl tert-butyl ether + 1-butanol + n-hexane). In addition, excess molar volumes, V{sup E}, and excess isentropic compressibility, {kappa}{sub s}{sup E}, were calculated from experimental data. Finally, experimental excess enthalpies results are compared with the estimations obtained by applying the group-contribution models of UNIFAC (in the versions of Dang and Tassios, Larsen et al., Gmehling et al.), and DISQUAC.

  18. Determination of methyl tert-butyl ether (MTBE) in Chinese fuels by gas chromatography/mass spectrometry and gas chromatography/flame ionization detector

    Institute of Scientific and Technical Information of China (English)

    LIU Jie-min; CHENG Wei; WEN Mei-juan; JIANG Gui-bin

    2004-01-01

    A method was developed to determine the concentration of methyl tert-butyl ether(MTBE) in gasoline,diesel and heating oil by gas chromatography(GC) with mass spectrometry(GC-MS) or flame ionization detection (FID). The diluted gasoline was directly injected into the GC, and the complete separation of MTBE from co-eluting hydrocarbons was not required. GC/MS or GC/FID method can be used to analyze MTBE in different concentration range and have good consistency.

  19. Oxidation of methyl tert-butyl ether by alkane hydroxylase in dicyclopropylketone-induced and n-octane-grown Pseudomonas putida GPo1.

    Science.gov (United States)

    Smith, Christy A; Hyman, Michael R

    2004-08-01

    The alkane hydroxylase enzyme system in Pseudomonas putida GPo1 has previously been reported to be unreactive toward the gasoline oxygenate methyl tert-butyl ether (MTBE). We have reexamined this finding by using cells of strain GPo1 grown in rich medium containing dicyclopropylketone (DCPK), a potent gratuitous inducer of alkane hydroxylase activity. Cells grown with DCPK oxidized MTBE and generated stoichiometric quantities of tert-butyl alcohol (TBA). Cells grown in the presence of DCPK also oxidized tert-amyl methyl ether but did not appear to oxidize either TBA, ethyl tert-butyl ether, or tert-amyl alcohol. Evidence linking MTBE oxidation to alkane hydroxylase activity was obtained through several approaches. First, no TBA production from MTBE was observed with cells of strain GPo1 grown on rich medium without DCPK. Second, no TBA production from MTBE was observed in DCPK-treated cells of P. putida GPo12, a strain that lacks the alkane-hydroxylase-encoding OCT plasmid. Third, all n-alkanes that support the growth of strain GPo1 inhibited MTBE oxidation by DCPK-treated cells. Fourth, two non-growth-supporting n-alkanes (propane and n-butane) inhibited MTBE oxidation in a saturable, concentration-dependent process. Fifth, 1,7-octadiyne, a putative mechanism-based inactivator of alkane hydroxylase, fully inhibited TBA production from MTBE. Sixth, MTBE-oxidizing activity was also observed in n-octane-grown cells. Kinetic studies with strain GPo1 grown on n-octane or rich medium with DCPK suggest that MTBE-oxidizing activity may have previously gone undetected in n-octane-grown cells because of the unusually high K(s) value (20 to 40 mM) for MTBE.

  20. Manipulation of the HIF–Vegf pathway rescues methyl tert-butyl ether (MTBE)-induced vascular lesions

    Energy Technology Data Exchange (ETDEWEB)

    Bonventre, Josephine A., E-mail: josephine.bonventre@oregonstate.edu [Rutgers, The State University of New Jersey, Joint Graduate Program in Toxicology, 170 Frelinghuysen Road, Piscataway, NJ 08854 (United States); Rutgers, The State University of New Jersey, Department of Biochemistry and Microbiology, 76 Lipman Dr., New Brunswick, NJ 08901 (United States); Oregon State University, Department of Environmental and Molecular Toxicology, 1011 Agricultural and Life Sciences Bldg, Corvallis, OR 97331 (United States); Kung, Tiffany S., E-mail: tiffany.kung@rutgers.edu [Rutgers, The State University of New Jersey, Joint Graduate Program in Toxicology, 170 Frelinghuysen Road, Piscataway, NJ 08854 (United States); Rutgers, The State University of New Jersey, Department of Biochemistry and Microbiology, 76 Lipman Dr., New Brunswick, NJ 08901 (United States); White, Lori A., E-mail: lawhite@aesop.rutgers.edu [Rutgers, The State University of New Jersey, Joint Graduate Program in Toxicology, 170 Frelinghuysen Road, Piscataway, NJ 08854 (United States); Rutgers, The State University of New Jersey, Department of Biochemistry and Microbiology, 76 Lipman Dr., New Brunswick, NJ 08901 (United States); Cooper, Keith R., E-mail: cooper@aesop.rutgers.edu [Rutgers, The State University of New Jersey, Joint Graduate Program in Toxicology, 170 Frelinghuysen Road, Piscataway, NJ 08854 (United States); Rutgers, The State University of New Jersey, Department of Biochemistry and Microbiology, 76 Lipman Dr., New Brunswick, NJ 08901 (United States)

    2013-12-15

    Methyl tert-butyl ether (MTBE) has been shown to be specifically anti-angiogenic in piscine and mammalian model systems at concentrations that appear non-toxic in other organ systems. The mechanism by which MTBE targets developing vascular structures is unknown. A global transcriptome analysis of zebrafish embryos developmentally exposed to 0.00625–5 mM MTBE suggested that hypoxia inducible factor (HIF)-regulated pathways were affected. HIF-driven angiogenesis via vascular endothelial growth factor (vegf) is essential to the developing vasculature of an embryo. Three rescue studies were designed to rescue MTBE-induced vascular lesions: pooled blood in the common cardinal vein (CCV), cranial hemorrhages (CH), and abnormal intersegmental vessels (ISV), and test the hypothesis that MTBE toxicity was HIF–Vegf dependent. First, zebrafish vegf-a over-expression via plasmid injection, resulted in significantly fewer CH and ISV lesions, 46 and 35% respectively, in embryos exposed to 10 mM MTBE. Then HIF degradation was inhibited in two ways. Chemical rescue by N-oxaloylglycine significantly reduced CCV and CH lesions by 30 and 32% in 10 mM exposed embryos, and ISV lesions were reduced 24% in 5 mM exposed zebrafish. Finally, a morpholino designed to knock-down ubiquitin associated von Hippel–Lindau protein, significantly reduced CCV lesions by 35% in 10 mM exposed embryos. In addition, expression of some angiogenesis related genes altered by MTBE exposure were rescued. These studies demonstrated that MTBE vascular toxicity is mediated by a down regulation of HIF–Vegf driven angiogenesis. The selective toxicity of MTBE toward developing vasculature makes it a potentially useful chemical in the designing of new drugs or in elucidating roles for specific angiogenic proteins in future studies of vascular development. - Highlights: • Global gene expression of MTBE exposed zebrafish suggested altered HIF1 signaling. • Over expression of zebrafish vegf-a rescues MTBE

  1. Pulse radiolysis study of reactions of alkyl and alkylperoxy radicals originating from methyl tert-butyl ether in the gas phase

    DEFF Research Database (Denmark)

    Langer, S.; Ljungström, E.; Ellermann, T.;

    1995-01-01

    UV spectra and kinetics for the reactions of alkyl and alkylperoxy radicals from methyl tert-butyl ether (MTBE) were studied in 1 atm of SF6 by the pulse radiolysis-UV absorption technique. UV spectra for the radical mixtures were quantified from 215 to 340 nm. At 240 nm, sigma(R) = (2.6 +/- 0.4) X...... 10(-18) cm(2) molecule(-1) and sigma(RO2) = (4.1 +/- 0.6) X 10(-18) cm(2) molecule(-1) (base e). The rate constant for the self-reaction of the alkyl radicals is (2.5 +/- 1.1) X 10(-11) cm(3) molecule(-1) s(-1). The rate constants for reaction of the alkyl radicals with molecular oxygen...... and the alkylperoxy radicals with NO and NO2 are (9.1 +/- 1.5) X 10(-13), (4.3 +/- 1.6) X 10(-12) and (1.2 +/- 0.3) X 10(-11) cm(3) molecule(-1) s(-1), respectively. The rate constants given above refer to reaction at the tert-butyl side of the molecule....

  2. Synthesis and characterization of di- and triorganotin(IV) complexes of 2-tert-butyl-4-methyl phenol

    Indian Academy of Sciences (India)

    Neeraj Sharma; Archana; Maridula Thakur; S S Bhatt; S C Chaudhry

    2007-07-01

    The di- and trialkyltin(IV) complexes of composition R2SnCl2-(OAr), and -Bu3Sn(OAr) (R = -Bu and Me; = 1 and 2; OAr = OC6H3Bu-2-Me-4) have been synthesized by the reactions of di-n-butyl and dimethyltin dichlorides and tri-n-butyltin(IV) chloride with 2-tert-butyl-4-methylphenol and triethylamine in tetrahydrofuran. The reaction of triphenyltin chloride with trimethylsilyl-2-t-butyl-4-methylphenoxide in the same solvent however, gives a complex of composition Ph3Sn(OAr). The complexes have been characterized by microanalyses, molar conductance measurements, molecular weight determinations and IR and 1H, 13C and 119Sn NMR and mass spectral studies. Thermal behaviour of the complexes has been studied by TGA and DTA techniques. From the non-isothermal TG data, the kinetic and thermodynamic parameters have been calculated employing Coats-Redfern equation and the mechanism of decomposition has been computed using non-isothermal kinetic method. Thermal investigations on the blends of poly(methylmethacrylate). PMMA, with organotin(IV)-2-tert-butyl-4-methylphenoxides have shown increased thermal stability compared to pure PMMA suggesting thereby their potential as additives towards PMMA.

  3. 7-[(3,5-Di-tert-butyl-2-hydroxybenzylideneamino]-4-methyl-2H-chromen-2-one

    Directory of Open Access Journals (Sweden)

    Orhan Büyükgüngör

    2010-10-01

    Full Text Available The title compound, C25H29NO3, is a Schiff base derivative of coumarin 120. There are two structurally similar but crystallographically independent molecules in the asymmetric unit. Both molecules exist in E configurations with respect to the C=N double bonds. The dihedral angles between the coumarin and 3,5-di-tert-butyl-2-hydroxybenzylidene ring planes are 4.62 (7 and 14.62 (7° for the two molecules. Intramolecular O—H...N hydrogen bonding involving the O—H groups and the azomethine N atoms generate S(6 rings. In the crystal structure, independent molecules are linked by C—H...π interactions, with groups of four molecules stacked along the c axis.

  4. Crystal structure of (1,3-di-tert-butyl-η5-cyclo­penta­dien­yl)tri­methyl­hafnium(IV)

    Science.gov (United States)

    Pérez-Redondo, Adrián; Varela-Izquierdo, Víctor; Yélamos, Carlos

    2015-01-01

    The mol­ecule of the title organometallic hafnium(IV) com­pound, [Hf(CH3)3(C13H21)] or [HfMe3(η5-C5H3-1,3-tBu2)], adopts the classical three-legged piano-stool geometry for mono­cyclo­penta­dienylhafnium(IV) derivatives with the three methyl groups bonded to the Hf(IV) atom at the legs. The C atoms of the two tert-butyl group bonded to the cyclo­penta­dienyl (Cp) ring are 0.132 (5) and 0.154 (6) Å above the Cp least-squares plane. There are no significant inter­molecular inter­actions present between the mol­ecules in the crystal structure. PMID:25995884

  5. Crystal structure of (1,3-di-tert-butyl-η(5)-cyclo-penta-dien-yl)tri-methyl-hafnium(IV).

    Science.gov (United States)

    Pérez-Redondo, Adrián; Varela-Izquierdo, Víctor; Yélamos, Carlos

    2015-05-01

    The mol-ecule of the title organometallic hafnium(IV) com-pound, [Hf(CH3)3(C13H21)] or [HfMe3(η(5)-C5H3-1,3- (t) Bu2)], adopts the classical three-legged piano-stool geometry for mono-cyclo-penta-dienylhafnium(IV) derivatives with the three methyl groups bonded to the Hf(IV) atom at the legs. The C atoms of the two tert-butyl group bonded to the cyclo-penta-dienyl (Cp) ring are 0.132 (5) and 0.154 (6) Å above the Cp least-squares plane. There are no significant inter-molecular inter-actions present between the mol-ecules in the crystal structure.

  6. Metabolism of methyl tert-butyl ether and other gasoline ethers in mouse liver microsomes lacking cytochrome P450 2E1.

    Science.gov (United States)

    Hong, J Y; Wang, Y Y; Bondoc, F Y; Yang, C S; Gonzalez, F J; Pan, Z; Cokonis, C D; Hu, W Y; Bao, Z

    1999-03-08

    To reduce the production of pollutants in motor vehicle exhaust, methyl tert-butyl ether (MTBE) and other ethers such as ethyl tert-butyl ether (ETBE) and tert-amyl methyl ether (TAME) are added to gasoline as oxygenates for more complete combustion. Metabolism of these gasoline ethers is catalyzed by cytochrome P450 (P450) enzymes. P450 2E1, which metabolizes diethyl ether, was suggested to be an enzyme involved. The present study used 2E1 knock-out mice (2E1-/-) to assess the contribution of 2E1 to the metabolism of MTBE, ETBE and TAME. Liver microsomes prepared from the 2E1 knock-out mice lacked 2E1 activity (assayed as N-nitrosodimethylamine demethylation), but were still active in metabolizing all three gasoline ethers. The levels of ether-metabolizing activity (nmol/min per mg) in the liver microsomes from 7 week old female 2E1 knock-out mice were 0.54+/-0.17 for MTBE, 0.51+/-0.24 for ETBE and 1.14+/-0.25 for TAME at a 1 mM substrate concentration. These activity levels were not significantly different from those of the sex- and age-matched C57BL/6N and 129/Sv mice, which are the parental lineage strains of the 2E1 knock-out mice and are both 2E1+/+. Our results clearly demonstrate that 2E1 plays a negligible role in the metabolism of MTBE, ETBE and TAME in mouse livers.

  7. Solid-Solid Phase Transitions and tert-Butyl and Methyl Group Rotation in an Organic Solid: X-ray Diffractometry, Differential Scanning Calorimetry, and Solid-State (1)H Nuclear Spin Relaxation.

    Science.gov (United States)

    Beckmann, Peter A; McGhie, Andrew R; Rheingold, Arnold L; Sloan, Gilbert J; Szewczyk, Steven T

    2017-08-24

    Using solid-state (1)H nuclear magnetic resonance (NMR) spin-lattice relaxation experiments, we have investigated the effects of several solid-solid phase transitions on tert-butyl and methyl group rotation in solid 1,3,5-tri-tert-butylbenzene. The goal is to relate the dynamics of the tert-butyl groups and their constituent methyl groups to properties of the solid determined using single-crystal X-ray diffraction and differential scanning calorimetry (DSC). On cooling, the DSC experiments see a first-order, solid-solid phase transition at either 268 or 155 K (but not both) depending on thermal history. The 155 K transition (on cooling) is identified by single-crystal X-ray diffraction to be one from a monoclinic phase (above 155 K), where the tert-butyl groups are disordered (that is, with a rotational 6-fold intermolecular potential dominating), to a triclinic phase (below 155 K), where the tert-butyl groups are ordered (that is, with a rotational 3-fold intermolecular potential dominating). This transition shows very different DSC scans when both a 4.7 mg polycrystalline sample and a 19 mg powder sample are used. The (1)H spin-lattice relaxation experiments with a much larger 0.7 g sample are very complicated and, depending on thermal history, can show hysteresis effects over many hours and over very large temperature ranges. In the high-temperature monoclinic phase, the tert-butyl groups rotate with NMR activation energies (closely related to rotational barriers) in the 17-23 kJ mol(-1) range, and the constituent methyl groups rotate with NMR activation energies in the 7-12 kJ mol(-1) range. In the low-temperature triclinic phase, the rotations of the tert-butyl groups and their methyl groups in the aromatic plane are quenched (on the NMR time scale). The two out-of-plane methyl groups in the tert-butyl groups are rotating with activation energies in the 5-11 kJ mol(-1) range.

  8. Reutilization of waste scrap tyre as the immobilization matrix for the enhanced bioremoval of a monoaromatic hydrocarbons, methyl tert-butyl ether, and chlorinated ethenes mixture from water.

    Science.gov (United States)

    Lu, Qihong; de Toledo, Renata Alves; Xie, Fei; Li, Junhui; Shim, Hojae

    2017-04-01

    BTEX (benzene, toluene, ethylbenzene, ortho-, meta-, and para-xylenes), methyl tert-butyl ether (MTBE), cis-1,2-dichloroethylene (cis-DCE), and trichloroethylene (TCE) are among the major soil and groundwater contaminants frequently co-existing, as a result of their widespread uses. Pseudomonas plecoglossicida was immobilized on waste scrap tyre to remove these contaminants mixture from synthetic contaminated water. The microbial activity was enhanced in the immobilized system, shown by the higher colony forming units (CFUs) (40%), while BTEX were used as growth substrates. The adsorption capacity of tyres toward contaminants reached a maximum within one day, with BTEX (76.3%) and TCE (64.3%) showing the highest sorption removal capacities, followed by cis-DCE (30.0%) and MTBE (11.0%). The adsorption data fitted the Freundlich isotherm with a good linear correlation (0.989-0.999) for the initial contaminants concentration range applied (25-125mg/L). The monoaromatic hydrocarbons were almost completely removed in the immobilized system and the favourable removal efficiencies of 78% and 90% were obtained for cis-DCE and TCE, respectively. The hybrid (biological, immobilization/physical, sorption) system was further evaluated with the contaminants spiked intermittently for the stable performance. The addition of mineral salt medium further enhanced the bioremoval of contaminants by stimulating the microbial growth to some extent.

  9. Cytotoxic and DNA-damaging effects of methyl tert-butyl ether and its metabolites on HL-60 cells in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Tang, G.H. [Xian Medical Univ. (China); Shen, Y.; Shen, H.M. [National Univ. of Singapore (Singapore)] [and others

    1996-12-31

    Methyl tert-butyl ether (MTBE) is a widely used oxygenate in unleaded gasoline; however, few studies have been conducted on the toxicity of this compound. This study evaluates the cytotoxic and DNA-damaging effects of MTBE and its metabolites in a human haemopoietic cell line, HL-60. The metabolites of MTBE studied include tertiary butyl alcohol (TBA), {alpha}-hydroxyisobutyric acid (HIBA), and formaldehyde. Comet assay is used to assess DNA damage, and the cytotoxicity is investigated by lactate dehydrogenease (LDH) release. The results show no significant cytotoxic effects of MTBE, TBA, and HIBA over a concentration ranging from 1 to 30 mM. Formaldehyde, in contrast, causes a substantial LDH release at a concentration of 5 {mu}M. Hydrogen peroxide, a known oxidative agent, at concentrations ranging from 10 to 100 {mu}M, produces a significant dose-related increase in DNA damage, whereas a much higher concentration of MTBE (1 to 30 mM) is required to produce a similar observation. The genotoxic effects of TBA and HIBA appear to be identical to that of MTBE. Conversely, DNA damage is observed for formaldehyde at a relatively low concentration range (5 to 100 {mu}M). These findings suggest that MTBE and its metabolites, except formaldehyde, have relatively low cytotoxic and genotoxic effects. 16 refs., 4 figs.

  10. Polypyrrole-Grafted Coconut Shell Biological Carbon as a Potential Adsorbent for Methyl Tert-Butyl Ether Removal: Characterization and Adsorption Capability.

    Science.gov (United States)

    Li, Shanshan; Qian, Keke; Wang, Shan; Liang, Kaiqiang; Yan, Wei

    2017-01-24

    Methyl tert-butyl ether (MTBE) has been used as a common gasoline additive worldwide since the late twentieth century, and it has become the most frequently detected groundwater pollutant in many countries. This study aimed to synthesize a novel microbial carrier to improve its adsorptive capacity for MTBE and biofilm formation, compared to the traditional granular activated carbon (GAC). A polypyrrole (PPy)-modified GAC composite (PPy/GAC) was synthesized, and characterized by Fourier transform infrared spectroscopy (FT-IR) and Brunauer-Emmett-Teller (BET) surface area analysis. The adsorption behaviors of MTBE were well described by the pseudo-second-order and Langmuir isotherm models. Furthermore, three biofilm reactors were established with PPy/GAC, PPy, and GAC as the carriers, respectively, and the degradation of MTBE under continuous flow was investigated. Compared to the biofilm reactors with PPy or GAC (which both broke after a period of operation), the PPy/GAC biofilm column produced stable effluents under variable treatment conditions with a long-term effluent MTBE concentration <20 μg/L. Pseudomonas aeruginosa and Acinetobacter pittii may be the predominant bacteria responsible for MTBE degradation in these biofilm reactors.

  11. Simultaneous determination of methyl tert.-butyl ether and its degradation products, other gasoline oxygenates and benzene, toluene, ethylbenzene and xylenes in Catalonian groundwater by purge-and-trap-gas chromatography-mass spectrometry.

    Science.gov (United States)

    Rosell, Mònica; Lacorte, Sílvia; Ginebreda, Antoni; Barceló, Damià

    2003-05-02

    In Catalonia (northeast Spain), a monitoring program was carried out to determine methyl tert.-butyl ether (MTBE), its main degradation products, tert.-butyl alcohol (TBA), tert.-butyl formate (TBF), and other gasoline additives, the oxygenate dialkyl ethers ethyl tert.-butyl ether, tert.-amyl methyl ether and diisopropyl ether and the aromatic compounds benzene, toluene, ethylbenzene and xylene (BTEX) in 21 groundwater wells that were located near different gasoline point sources (a gasoline spill and underground storage tank leakage). Purge-and-trap coupled to gas chromatography-mass spectrometry was optimised for the simultaneous determination of the above mentioned compounds and enabled to detect concentrations at ng/l or sub-microg/l concentrations. Special attention was given to the determination of polar MTBE degradation products, TBA and TBF, since not much data on method performance and environmental levels are given on these compounds in groundwater. All samples analysed contained MTBE at levels between 0.3 and 70 microg/l. Seven contaminated hot spots were identified with levels up to US Environmental Protection Agency drinking water advisory (20-40 microg/l) and a maximum concentration of 670 microg/l (doubling the Danish suggested toxicity level of 350 microg/l). Samples with high levels of MTBE contained 0.1-60 microg/l of TBA, indicating (but not proving) in situ degradation of parent compound. In all cases, BTEX was at low concentrations or not detected showing less solubility and persistence than MTBE. This fact confirms the suitability of MTBE as a tracer or indicator of long-term gasoline contamination than the historically used BTEX.

  12. Effect of Ethanol and Methyl-tert-Butyl Ether on Monoaromatic Hydrocarbon Biodegradation: Response Variability for Different Aquifer Materials Under Various Electron-Accepting Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Ruiz-Aguilar, G L; Fernandez-Sanchez, J M; Kane, S R; Kim, D; Alvarez, P J

    2003-10-06

    Aquifer microcosms were used to determine how ethanol and methyl-tert-butyl ether (MtBE) affect monoaromatic hydrocarbon degradation under different electron-accepting conditions commonly found in contaminated sites experiencing natural attenuation. Response variability was investigated by using aquifer material from four sites with different exposure history. The lag phase prior to BTEX (benzene, toluene, ethylbenzene, and xylenes) and ethanol degradation was typically shorter in microcosms with previously contaminated aquifer material, although previous exposure did not always result in high degradation activity. Toluene was degraded in all aquifer materials and generally under a broader range of electron-accepting conditions compared to benzene, which was degraded only under aerobic conditions. MtBE was not degraded within 100 days under any condition, and it did not affect BTEX or ethanol degradation patterns. Ethanol was often degraded before BTEX compounds, and had a variable effect on BTEX degradation as a function of electron-accepting conditions and aquifer material source. An occasional enhancement of toluene degradation by ethanol occurred in denitrifying microcosms with unlimited nitrate; this may be attributable to the fortuitous growth of toluene-degrading bacteria during ethanol degradation. Nevertheless, experiments with flow-through aquifer columns showed that this beneficial effect could be eclipsed by an ethanol-driven depletion of electron acceptors, which significantly inhibited BTEX degradation and is probably the most important mechanism by which ethanol could hinder BTEX natural attenuation. A decrease in natural attenuation could increase the likelihood that BTEX compounds reach a receptor as well as the potential duration of exposure.

  13. Using groundwater age distributions to understand changes in methyl tert-butyl ether (MtBE) concentrations in ambient groundwater, northeastern United States

    Science.gov (United States)

    Lindsey, Bruce; Ayotte, Joseph; Jurgens, Bryant; DeSimone, Leslie

    2017-01-01

    Temporal changes in methyl tert-butyl ether (MtBE) concentrations in groundwater were evaluated in the northeastern United States, an area of the nation with widespread low-level detections of MtBE based on a national survey of wells selected to represent ambient conditions. MtBE use in the U.S. peaked in 1999 and was largely discontinued by 2007. Six well networks, each representing specific areas and well types (monitoring or supply wells), were each sampled at 10 year intervals between 1996 and 2012. Concentrations were decreasing or unchanged in most wells as of 2012, with the exception of a small number of wells where concentrations continue to increase. Statistically significant increasing concentrations were found in one network sampled for the second time shortly after the peak of MtBE use, and decreasing concentrations were found in two networks sampled for the second time about 10 years after the peak of MtBE use. Simulated concentrations from convolutions of estimates for concentrations of MtBE in recharge water with age distributions from environmental tracer data correctly predicted the direction of MtBE concentration changes in about 65 percent of individual wells. The best matches between simulated and observed concentrations were found when simulating recharge concentrations that followed the pattern of national MtBE use. Some observations were matched better when recharge was modeled as a plume moving past the well from a spill at one point in time. Modeling and sample results showed that wells with young median ages and narrow age distributions responded more quickly to changes in the contaminant source than wells with older median ages and broad age distributions. Well depth and aquifer type affect these responses. Regardless of the timing of decontamination, all of these aquifers show high susceptibility for contamination by a highly soluble, persistent constituent.

  14. Sensitivity of green and blue-green algae to methyl tert-butyl ether (MTBE) during a fifteen-day test

    Institute of Scientific and Technical Information of China (English)

    CHEN Jianmeng; MA Jianyi; CAO Wei; WANG Pinwei; TONG Senmiao; SUN Yizhao

    2009-01-01

    The test was designed to assess the toxicity of methyl tert-butyl ether (MTBE) to Chlorella ellipsoidea and Aphanizomenon flos-aquae during 15 d with concentrations of MTBE from high (2.00×104 mg/L) to low (2 mg/L). The results showed that the toxicity was low when the concentration of MTBE was 1.00×104-2.00×104 mg/L (the greatest inhibition of growth-rate was 70%-71%, occurring on day 1-5). Low concentrations (2-500 mg/L) stimulated algal growth up to the greatest effect of 85%-200% when the concentration of MTBE was 50-100 mg/L on day 3-5. The low concentrations may lead to an algal bloom owing to overabundance, which represents an aquatic ecological risk. However, the stimulatory effect occurred only during the day 1-5 and disappeared gradually during the day 13-15. The toxicity of MTBE (72-120 h EC50) is 6.65×103-9.58×103 mg/L for C. ellipsoidea and that is 1.14×104-2.00×104 mg/L for A. spiroides. We found that the toxicity and ecological risk of MTBE for the algal community structure were low. The toxicity was influenced by the duration of the test. We suggest that the duration of the test should not be shorter than half a life-cycle.

  15. Volumetric behaviour of the ternary liquid system composed of methyl tert-butyl ether, toluene, and isooctane at temperatures from (298.15 to 328.15) K: Experimental data and correlation

    Energy Technology Data Exchange (ETDEWEB)

    Moravkova, L.; Wagner, Z.; Sedlakova, Z. [E. Hala Laboratory of Thermodynamics, Institute of Chemical Process Fundamentals of the ASCR, v.v.i., 165 02 Prague 6 (Czech Republic); Linek, J., E-mail: linek@icpf.cas.c [E. Hala Laboratory of Thermodynamics, Institute of Chemical Process Fundamentals of the ASCR, v.v.i., 165 02 Prague 6 (Czech Republic)

    2010-07-15

    The densities and speeds of sound of (methyl tert-butyl ether left braceMTBEright brace + toluene + isooctane) were measured at four temperatures over the range (298.15 to 328.15) K and the respective values of excess volumes V{sub m}{sup E} and adiabatic compressibility kappa{sub S} were calculated. The V{sub m}{sup E} and kappa{sub S} values for the ternary and corresponding binaries were fitted to the Redlich-Kister equation considering various numbers of ternary constants. The necessary number of ternary constants needed to describe the system is discussed.

  16. Metabolism of methyl tert-butyl ether and other gasoline ethers by human liver microsomes and heterologously expressed human cytochromes P450: identification of CYP2A6 as a major catalyst.

    Science.gov (United States)

    Hong, J Y; Wang, Y Y; Bondoc, F Y; Lee, M; Yang, C S; Hu, W Y; Pan, J

    1999-10-01

    To reduce the production of carbon monoxide and other pollutants in motor vehicle exhaust, methyl tert-butyl ether (MTBE), ethyl tert-butyl ether (ETBE), and tert-amyl methyl ether (TAME) are added to gasoline as oxygenates for more complete combustion. Previously, we demonstrated that human liver is active in metabolizing MTBE to tert-butyl alcohol (TBA) and that cytochrome P450 (CYP) enzymes play a critical role in the metabolism of MTBE. The present study demonstrates that human liver is also active in the oxidative metabolism of ETBE and TAME. A large interindividual variation in metabolizing these gasoline ethers was observed in 15 human liver microsomal samples. The microsomal activities in metabolizing MTBE, ETBE, and TAME were highly correlated among each other (r, 0.91-0. 96), suggesting that these ethers are metabolized by the same enzyme(s). Correlation analysis of the ether-metabolizing activities with individual CYP enzyme activities in the liver microsomes showed that the highest degree of correlation was with human CYP2A6 (r, 0. 90-0.95), which is constitutively expressed in human livers and known to be polymorphic. CYP2A6 displayed the highest turnover number in metabolizing gasoline ethers among a battery of human CYP enzymes expressed in human B-lymphoblastoid cells. Kinetic studies on MTBE metabolism with three human liver microsomes exhibited apparent Km values that ranged from 28 to 89 microM and the V(max) values from 215 to 783 pmol/min/mg, with similar catalytic efficiency values (7.7 to 8.8 microl/min/mg protein). Metabolism of MTBE, ETBE, and TAME by human liver microsomes was inhibited by coumarin, a known substrate of human CYP2A6, in a concentration-dependent manner. Monoclonal antibody against human CYP2A6 caused a significant inhibition (75% to 95%) of the metabolism of MTBE, ETBE, and TAME in human liver microsomes. Taken together, these results clearly indicate that in human liver, CYP2A6 is the major enzyme responsible for the

  17. 用于脱除C5及MTBE中甲醇的渗透汽化膜研究%Study on Pervaporation Membranes for Removing Methanol from C5 or Methyl Tert-butyl Ether Mixtures

    Institute of Scientific and Technical Information of China (English)

    张林; 陈欢林; 周志军; 钱锦文; 高从堦; 潘祖仁

    2003-01-01

    Several pervaporation membranes, cellulose acetate (CA), polyvinylbutyral (PVB), poly(MMA-co-AA),MMA-AA-BA, CA/PVB blend and CA/poly(MMA-co-AA) blend, were prepared, and their pervaporation properties were evaluated by separation of methanol/C5 or methanol/MTBE (methyl tert-butyl ether). The results shows that the CA composite membrane has a high separation performance (flux Jmethanol = 350 g.m-2.h-1 and separation factor α>400) for methanol/C5 mixtures, and the pervaporation characteristics of MMA-AA-BA copolymer membranes changes with the ratio of copolymer. For CA/poly(MMA-co-AA) blend membrane, the pervaporation performance is improved in comparison with CA or poly(MMA-co-AA) membrane. From the experiment of CA/PVB blend membranes for methanol/MTBE mixture, it is found that the compatibility of blends may affect the separation features of blend membrane.

  18. 2-(tert-Butyl-4-phenyloxetane

    Directory of Open Access Journals (Sweden)

    Filippo Maria Perna

    2017-02-01

    Full Text Available The two geometric isomers of 2-(tert-butyl-4-phenyloxetane have, for the first time, been prepared starting from the commercially available 4,4-dimethyl-1-phenylpentane-1,3-dione. The latter was reduced with NaBH4 to give a mixture of diastereomeric syn and anti diols which were then stereospecifically cyclized into the corresponding oxetanes with an overall yield for the two steps of 69.6%. The newly synthesized stereoisomeric four-membered oxygenated heterocycles were separated by column chromatography on silica gel and fully spectroscopically characterized.

  19. Organic Semiconductors and Conductors with tert-Butyl Substituents

    Directory of Open Access Journals (Sweden)

    Toshiki Higashino

    2012-08-01

    Full Text Available Tetrathiafulvalene (TTF, pentacene, and quarterthiophene with tert-butyl substituents are synthesized, and the crystal structures and the transistor properties are investigated. The tetracyanoquinodimethane (TCNQ complex of tert-butyl TTF constructs highly one-dimensional segregated columns with tetragonal crystal symmetry.

  20. Synthesis and complexation properties towards uranyl cation of carboxylic acid derivatives of p-tert-butyl-calix[6]arene; Synthese et proprietes complexantes vis-a-vis de l'ion uranyle de derives carboxyliques du p-tert-butyl-calix[6]arene

    Energy Technology Data Exchange (ETDEWEB)

    Souane, R

    2005-03-15

    In the fuel reprocessing plants radioactive metals, and more particularly, uranium in UO{sub 2}{sup 2+} form in the various installations, have many varied physico-chemical forms and there is a risk of exposure and internal contamination in the nuclear industry. It is necessary to exert a medical control to ensure the protection of the health of the workers. This medical control is done by dosing uranyl cation in the urine of the exposed people. This work forms part of this context. Indeed, we prepared a ligand able to complex the ion uranyl and which is also to be grafted on a solid support. In the family of calixarenes, the calix[6]arenes functionalized by three or four carboxylic functions were selected like chelating molecules of the ion uranyl. The properties of complexation of these calixarenes were studied by potentiometry in methanol, under these conditions balances of protonation and complexation were determined and the constant partners were obtained using the Hyperquad program. We synthesized tri-carboxylic calix[6]arenes comprising of the groupings nitro (NO{sub 2}) in para position of phenol in order to see the influence of a substitution in para position on the complexation. We also synthesized calix[6]arenes tetra-carboxylic in order to show the role of an additional carboxylic acid grouping. The potentiometric study determined thermodynamic parameters of protonation and complexation of carboxylic calix[6]arenes. The results of the complexation highlighted which complex UO{sub 2}L corresponding to the ligand para-tert-butyl-calix[6]arene tetra-acid is more stable than that corresponding to the ligand mono-nitro calix[6]arene tri-acid ({delta}log{beta}110 = 4.3), and than the effect of the groupings nitro in para position has low influence on the complexation of UO{sub 2}{sup 2+}. This makes it possible to consider as possible the grafting of the calix[6]arenes which one knows the behaviour of trapping. To this end we synthesized the ligand 23

  1. 1-[(E-2-(5-tert-Butyl-2-hydroxyphenyldiazen-1-yl]naphthalen-2-ol

    Directory of Open Access Journals (Sweden)

    Hassiba Bougueria

    2014-02-01

    Full Text Available The non-H atoms of the title compound, C20H20N2O2, is located on a mirror plane except two methyl groups of the tert-butyl group. Intramolecular N—H...O hydrogen bonds exist between the hydroxy and diazenyl groups. In the crystal, molecules are linked by weak C—H...O hydrogen bonds into supramolecular chains running along the a-axis direction.

  2. Phenol Tert-Butylation Catalyzed by Zeolite H-Mordenite

    Institute of Scientific and Technical Information of China (English)

    HAN Sen; LI Zhenhua; ZHANG Kui

    2005-01-01

    Para-tert-butyl phenol (p-TBP) and 2,4-di-tert-butyl phenol (2,4-DTBP) are widely used for the preparation of antioxidants. Zeolite catalysts showed good performance for the synthesis of p-TBP and 2,4-DTBP. In this work, zeolite H-mordenite (HM) catalyst was prepared and the alkylation of phenol with tert-butyl alcohol over zeolite HM catalyst was investigated at different reaction conditions. It is found that increasing temperature enhances the selectivity to p-TBP and the optimum reaction temperature for phenol conversion is 438 K. Increasing flow rate decreases phenol conversion apparently while the selectivity to p-TBP has a little increase. The suitable tert-butyl alcohol/phenol molar ratio is 2. Lower alcohol/phenol molar ratios are beneficial to p-TBP while higher ones are helpful for producing 2,4-DTBP.

  3. Synthesis and Characterization of a Gasoline Oxygenate, Ethyl tert-Butyl Ether

    Science.gov (United States)

    Donahue, Craig J.; D'Amico, Teresa; Exline, Jennifer A.

    2002-06-01

    A laboratory procedure involving the synthesis and characterization of ethyl tert-butyl ether (ETBE) is described. This experiment has been used in a general chemistry sequence that includes a section on organic chemistry, but is also well suited for an introductory organic chemistry laboratory course. ETBE is prepared by the acid-catalyzed reaction of tert-butyl alcohol with ethyl alcohol. The product is recovered as a low-boiling azeotrope and purified by liquid liquid extraction with water. By using gas chromatography and IR spectroscopy to examine both the crude and the purified products, students can see how much the purity of their sample improves. They can also appreciate the value of these methods (especially GC) as tools to establish purity. Student results are presented. The use of ETBE and its more prominent cousin methyl tert-butyl ether (MTBE) as gasoline oxygenates has become very controversial because they have polluted underground water supplies. This lab permits students to prepare a compound that has a real use and regularly makes headlines in the news. This lab experiment is part of an effort to develop a general chemistry sequence for engineering students using the theme of "Chemistry and the Automobile".

  4. Generation of free radicals from organic hydroperoxide tumor promoters in isolated mouse keratinocytes. Formation of alkyl and alkoxyl radicals from tert-butyl hydroperoxide and cumene hydroperoxide.

    Science.gov (United States)

    Taffe, B G; Takahashi, N; Kensler, T W; Mason, R P

    1987-09-05

    The organic hydroperoxides tert-butyl hydroperoxide and cumene hydroperoxide are tumor promoters in the skin of SENCAR mice, and this activity is presumed to be mediated through the activation of the hydroperoxides to free radical species. In this study we have assessed the generation of free radicals from organic hydroperoxides in the target cell (the murine basal keratinocyte) using electron spin resonance. Incubation of primary isolates of keratinocytes from SENCAR mice in the presence of spin traps (5,5-dimethyl-1-pyrroline N-oxide or 2-methyl-2-nitrosopropane) and either tert-butyl hydroperoxide or cumene hydroperoxide resulted in the generation and detection of radical adducts of these spin traps. tert-Butyl alkoxyl and alkyl radical adducts of 5,5-dimethyl-1-pyrroline N-oxide were detected shortly after addition of tert-butyl hydroperoxide, whereas only alkyl radical adducts were observed with cumene hydroperoxide. Spin trapping of the alkyl radicals with 2-methyl-2-nitrosopropane led to the identification of methyl and ethyl radical adducts following both tert-butyl hydroperoxide and cumene hydroperoxide exposures. Prior heating of the cells to 100 degrees C for 30 min prevented radical formation. The radical generating capacity of subcellular fractions of these epidermal cells was examined using 5,5-dimethyl-1-pyrroline N-oxide and cumene hydroperoxide, and this activity was confined to the 105,000 X g supernatant fraction.

  5. The tert-butyl group in chemistry and biology.

    Science.gov (United States)

    Bisel, Philippe; Al-Momani, Loay; Müller, Michael

    2008-08-07

    The unique reactivity pattern elicited by the crowded tert-butyl group is highlighted by summarising characteristic applications. Starting from the use of this simple hydrocarbon moiety in chemical transformations, via its relevance in Nature and its implication in biosynthetic and biodegradation pathways, the way through to its possible application in biocatalytic processes is described.

  6. 27 CFR 21.101 - tert-Butyl alcohol.

    Science.gov (United States)

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false tert-Butyl alcohol. 21.101 Section 21.101 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY LIQUORS FORMULAS FOR DENATURED ALCOHOL AND RUM Specifications for Denaturants §...

  7. Crystal structure of 4-azidomethyl-6-tert-butyl-2H-chromen-2-one

    Directory of Open Access Journals (Sweden)

    Nasseem El-Khatatneh

    2015-04-01

    Full Text Available In the title compound, C14H15N3O2, one of the methyl C atoms of the tert-butyl group lies almost in the plane of the chromene ring system [deviation = −0.097 (2 Å], one lies above and one lies below [deviations = 1.460 (3 and 1.006 (3 Å, respectively]. The C—C—N—N torsion angle is 142.33 (17°. In the crystal, moelcules are linked by weak C—H...O hydrogen bonds to generate C(6 chains propagating in the [010] direction.

  8. An Efficient Method for Synthesis of N-tert-Butyl Amides Using Oxalic Acid Dihydrate in Solvent-Free Condition

    Directory of Open Access Journals (Sweden)

    Masoud Mokhtary

    2014-01-01

    Full Text Available An efficient method for the synthesis of N-tert-butyl amides by reaction of nitriles with tert-butyl acetate or tert-butanol is described using oxalic acid dihydrate in solvent-free condition. The result showed that tert-butyl acetate served as a relatively better source of tert-butyl carbocation than tert-butanol.

  9. Tris(tert-butyl isocyanide-κCcarbonylnickel(0

    Directory of Open Access Journals (Sweden)

    Wolfgang Imhof

    2008-08-01

    Full Text Available The title compound, [Ni(C5H9N3(CO], was prepared from Ni(CO4 and a tenfold excess of tert-butyl isocyanide. It crystallizes with two symmetry-independent molecules per asymmetric unit. The central Ni atom of each independent molecule has a nearly perfect tetrahedral coordination environment, comprising one carbon monoxide and three isocyanide ligands. The title compound is the first structurally characterized Ni0 compound with a mixed CO/RNC coordination.

  10. tert-Butyl 2-benzoyl-2-methylpropanoate

    Directory of Open Access Journals (Sweden)

    Marshall W. Logue

    2010-02-01

    Full Text Available The title compound, C15H20O3, is bent with a dihedral angle of 67.28 (9° between the mean planes of the phenyl ring and a group encompassing the ester functionality (O=C—O—C. In the crystal, molecules related by inversion symmetry are connected by weak C—H...O interactions into infinite chains. On one side of the molecule there are two adjacent interactions between neighbouring molecules involving the H atoms of methyl groups from the dimethyl groups and the O atoms of the ketone; on the other side, there are also two interactions to another adjacent molecule involving the H atoms on the phenyl rings and the carbonyl O atoms of the ester functionality.

  11. tert-Butyl N-(thiophen-2-ylcarbamate

    Directory of Open Access Journals (Sweden)

    Gene C. Hsu

    2013-09-01

    Full Text Available In the title compound, C9H13NO2S, the dihedral angle between the thiophene ring and the carbamate group is 15.79 (14°. In the crystal structure, intramolecular C—H...O interactions in tandem with the tert-butyl groups render the packing of adjacent molecules in the [001] direction nearly perpendicular [the angle between adjacent thiophene rings is 74.83 (7°]. An intermolecular N—H...O hydrogen bond gives rise to a chain extending along [001]. The crystal studied was found to be a racemic twin.

  12. Crystal structure of (1,3-di-tert-butyl-η5-cyclopentadienyltrimethylhafnium(IV

    Directory of Open Access Journals (Sweden)

    Adrián Pérez-Redondo

    2015-05-01

    Full Text Available The molecule of the title organometallic hafnium(IV compound, [Hf(CH33(C13H21] or [HfMe3(η5-C5H3-1,3-tBu2], adopts the classical three-legged piano-stool geometry for monocyclopentadienylhafnium(IV derivatives with the three methyl groups bonded to the Hf(IV atom at the legs. The C atoms of the two tert-butyl group bonded to the cyclopentadienyl (Cp ring are 0.132 (5 and 0.154 (6 Å above the Cp least-squares plane. There are no significant intermolecular interactions present between the molecules in the crystal structure.

  13. UV/O3工艺去除甲基叔丁基醚过程中BrO3-的产生与控制%Bromate formation and control in process of removing methyl tert-butyl ether by UV/O3 technology

    Institute of Scientific and Technical Information of China (English)

    赵光宇; 吕锡武; 周易

    2013-01-01

    Bromate is a potential carcinogen and formed in treatment of bromide-containing water using ozone-based technologies.So,the study on bromate formation during removal of organic pollutions is necessary for applying UV/O3 process.The effects of water background,initial MTBE concentration,ozone dosage and dosing method on removal of methyl tert-butyl ether (MTBE) and formation of bromate were studied.Besides,the mechanism of action for ozone dosing method was explored.The results showed that MTBE removal rates obtained by UV/O3 process in ultrapure water and tap water were 93.5 % and 88.67%,and bromate concentration were 18.01 μg · L-1 and 12.13 μg· L-1,respectively,which were higher than the standard value of 10 μg · L-1.The promotion of initial MTBE concentration inhibited bromate formation,but longer reaction time were compulsory since MTBE concentration was required to be lower than proposed concentration of 5 μg · L-1.In this case,bromate formation was eventually enhanced.Increase of ozone dosage was favorable for MTBE removal,but caused decline of the utilization rate of ozone and the promotion of bromate formation.Comparing three ozone dosing methods in which the same ozone dosage of 5 mg · min · L-1 was applied,the highest hydroxyl radical (· OH) exposure and minimum ozone exposure were obtained in the method at ozone concentration of 0.75 mg · L-1 and reaction time of 120 min.Therefore,the concentrations of MTBE and bromate in water both met the standard values after treatment.

  14. (2,6-Bis{5-amino-3-tert-butyl-4-[(3-methyl-1,2,4-thiadiazol-5-yldiazenyl]-1H-pyrazol-1-yl}-4-oxo-1,4-dihydro-1,3,5-triazin-1-idomethanol(phenolsodium phenol tetrasolvate

    Directory of Open Access Journals (Sweden)

    Hiroki Shibata

    2010-04-01

    Full Text Available The title compound, [Na(C23H28N17OS2(CH3OH(C6H5OH]·4C6H5OH, is a five-coordinate NaI complex. The Na+ cation is bound to three N atoms of the triazinide ligand, two from each pyrazole ring and one from the central deprotonated triazine ring system. O atoms from a methanol and a phenol molecule complete the five-coordinate NaN3O2 coordination environment. The asymmetric unit also includes three complete and two half phenol molecules, four of which are hydrogen bonded to the N atoms of the thiadiazole ring. Two of the phenol solvent molecules are disordered over two discrete inversion centres. The triazinide ligand is essentially planar (mean deviation from the least-squares plane = 0.0524 Å, with the methyl groups of the tert-butyl substituents on the pyrazole rings located above and below the plane. The planarity of this system is further assisted by the formation of four intramolecular N—H...N hydrogen bonds between the N—H bonds of both amino groups on the pyrazole rings and the N atoms of the triazine ring and also from each of the adjacent diazene (–N=N– bonds. The highly polar molecules are stacked along the a axis through the central Na atom sandwiched by two kinds of alternating intermolecular hydrogen bonds: O(carbonyl...H—O(methanol/Na/O—H(phenol...O(carbonyl. These interactions form two polymer chains per molecule.

  15. Synthesis of Highly Porous Poly(tert-butyl acrylate)-b-polysulfone-b-poly(tert-butyl acrylate) Asymmetric Membranes

    KAUST Repository

    Xie, Yihui

    2016-03-24

    For the first time, self-assembly and non-solvent induced phase separation was applied to polysulfone-based linear block copolymers, reaching mechanical stability much higher than other block copolymers membranes used in this method, which were mainly based on polystyrene blocks. Poly(tert-butyl acrylate)-b-polysulfone-b-poly(tert-butyl acrylate) (PtBA30k-b-PSU14k-b-PtBA30k) with a low polydispersity of 1.4 was synthesized by combining step-growth condensation and RAFT polymerization. Various advanced electron microscopies revealed that PtBA30k-b-PSU14k-b-PtBA30k assembles into worm-like cylindrical micelles in DMAc and adopts a “flower-like” arrangement with the PSU central block forming the shell. Computational modeling described the mechanism of micelle formation and morphological transition. Asymmetric nanostructured membranes were obtained with a highly porous interconnected skin layer and a sublayer with finger-like macrovoids. Ultrafiltration tests confirmed a water permeance of 555 L m-2 h-1 bar-1 with molecular weight cut-off of 28 kg/mol. PtBA segments on the membrane surface were then hydrolyzed and complexed with metals, leading to cross-linking and enhancement of antibacterial capability.

  16. Thermal decomposition mechanism of p-tert-butyl-calix[n]arenes

    Energy Technology Data Exchange (ETDEWEB)

    Chennakesavulu, K., E-mail: chennanml@yahoo.com [National Metallurgical Laboratory Madras Centre, CSIR Madras Complex, Taramani, Chennai 600 113 (India); Department of Chemistry, Sathyabama University, Jeppiaar Nagar, Chennai 600 119 (India); Sreedevi, P.; Raviathul Basaria, M. [National Metallurgical Laboratory Madras Centre, CSIR Madras Complex, Taramani, Chennai 600 113 (India); Ramanjaneya Reddy, G. [Department of Inorganic Chemistry, Guindy Campus, University of Madras, Chennai 600 025 (India); Sasipraba, T. [International Research Centre, Sathyabama University, Jeppiaar Nagar, Chennai 600 119 (India); Bhaskar Raju, G.; Prabhakar, S. [National Metallurgical Laboratory Madras Centre, CSIR Madras Complex, Taramani, Chennai 600 113 (India)

    2014-01-10

    Highlights: • Systematic thermal decomposition, structural elucidation of intermediates at various quenched temperatures. • At solid state the phenolic free radical was quenched and was evidenced by recording stable EPR. • Since the lower decomposition energy these p-tert-butyl-calix[n]arenes can be used as a antioxidants for thermal stabilization of polyolefins. • Solid state NMR CP-MAS studies show the breakage of calixarene at bridged methylene. • Kinetic triplets of p-tert-butyl-calixarenes were determined by model free methods. - Abstract: Thermal decomposition of p-tert-butyl-calix[n]arene was studied using thermo gravimetry (TG) and differential thermo gram (DTG) methods. Non-isothermal TG was done under static air atmosphere with 1, 2.5, 5.0 and 10.0 K/min. Model-free methods such as Friedman and Flynn Wall Ozawa (FWO) were used to evaluate the kinetic parameters such as activation energy and exponential factors. The probable thermal decomposition mechanism was proposed by analyzing the quenched intermediate p-tert-butyl-calix[n]arene samples with FTIR, mass, {sup 1}H NMR, {sup 13}C NMR cross polarization magic angle spectrometry (CP-MAS), EPR spectroscopy and elemental analysis. The thermal stability of the polyolefins was checked with p-tert-butyl-calix[n]arene as an antioxidant additive.

  17. Alkylation of Catechol with tert-Butyl Alcohol Catalyzed by Mesoporous Acidic Montmorillonite Heterostructure Catalysts

    Institute of Scientific and Technical Information of China (English)

    周春晖; 葛忠华; 李小年; 童东绅; 李庆伟; 郭红强

    2004-01-01

    The liquid phase alkylation of catechol with tert-butyl alcohol to produce 4-tert-butyl catechol (4-TBC) was carried out over MCM-41, HZSM-5, H-exchanged montmorillonite and novel acidic porous montmorillonite heterostructures (PMHs). Upon all catalysts tested, 4-TBC is the main product and 3-tert-butyl catechol (3-TBC) and 3,5-di-tert-butyl catechol are the side products. The synthetic PMHs showed higher conversion of catechol and better selectivity to 4-TBC compared to other solid acid catalysts tested. Over the PMHs derived from H-exchanged montmorillonite through template extraction processes, the suitable reaction temperature is ca 410 K, the ratio of catechol to tert-butyl alcohol is 1:2. Increasing the amount of catalyst (lower weight hourly space velocity) can improve the conversion of catechol and influence the selectivity slightly. The reasonable reaction time is ca 8 h.The type and strength of acidity of H-montmorillonite and PMH were determined by pyridine adsorption FT-IR and ammonia temperature-programmed desorption techniques. The medium and strong acid sites are conducive to producing 4-TBC and the weak acid sites to facilitating the 3-TBC formation. The differences between the PMHs from calcination and those fi'om extraction are attributed to proton migration and acidity change in the gallery surface.

  18. Conformational analysis of cyclic sulphites. 2-Oxo 1,3,2-dioxathiane-4-spiro-4- tert-butyl-cyclohexanes

    Science.gov (United States)

    Cazaux, Louis; Koudsi, Yahia; Maroni, Pierre

    Three series of 4-spirosulphites, a new class of cyclic sulphites, were synthesized and five couples of diastereoisomers isolated. Their structural analysis, using 1H NMR coupling constants and SO stretching vibration as conformational probes, shows a large variety of ananchomeric chair forms and multicomponent equilibria for the cyclic sulphite moiety, the cyclohexane part of the molecule remaining in the chair form. Related to the occurrence of severe interactions involving the 5-methyl or 6- tert. butyl substituent, several twist forms were encountered, with 2,5-axis and isoclinal SO or 1,4-axis and axial or equatorial SO as a consequence of the weak free energy difference between chair and twist conformations in the cyclic sulphite series.

  19. A new efficient synthesis of isothiocyanates from amines using di-tert-butyl dicarbonate

    DEFF Research Database (Denmark)

    Munch, Henrik; Hansen, Jon S.; Pittelkow, Michael;

    2008-01-01

    Alkyl and aryl amines are converted smoothly to the corresponding isothiocyanates via the dithiocarbamates in good to excellent yields using di-tert-butyl dicarbonate (Boc(2)O) and 1-3 mol% of DMAP or DABCO as catalyst. As most of the byproducts are volatile, the work-up involves simple evaporation...

  20. (R-N-{2-tert-Butyl-2-[(R-tert-butylsulfonamido]ethylidene}-tert-butanesulfonamide

    Directory of Open Access Journals (Sweden)

    Cong-Bin Fan

    2008-10-01

    Full Text Available The title compound, C14H30N2O2S2, is the product of the monoaddition reaction of tert-butyl magnesium chloride with bis-[(R-N-tert-butanesulfinyl]ethanediimine. There are two almost identical molecules in the asymmetric unit, the molecular conformation of which is stabilized by an intramolecular N—H...N hydrogen bond.

  1. Kinetic Study of the Reaction between Tert-butyl Hydrazine and Nitrous Acid

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The kinetic study of the reaction between tert-butyl hydrazine(TBH)and nitrous acid in nitric acid system is performed by spectrophotometry. The effect of some factors such as the concentration of TBH, the concentration of nitric acid, ionic strength, temperature and the

  2. Bis[tris(3-tert-butyl-5-methylpyrazol-1-ylhydridoborato]ytterbium(II toluene solvate

    Directory of Open Access Journals (Sweden)

    Kuburat O. Saliu

    2009-06-01

    Full Text Available In the title compound, [Yb(C24H40BN62]·C7H8, the Yb atom is coordinated by two tris(3-tert-butyl-5-methylpyrazol-1-ylhydridoborate [TptBu,Me] ligands. One ligand binds in the κ3 mode, throuh three N atoms of the pyrazolyl rings, the other ligand coordinates through two N atoms of the pyrazolyl rings and the H atom attached to the central B via an agostic-type interaction through the B—H group of the second TptBu,Me ligand, giving an overall distorted octahedral geometry. One of the tert-butyl groups is disordered over two sites, with occupancies of 0.65 and 0.35.

  3. The oxidation of 2,6-di-tert-butyl-4-methylphenol

    Science.gov (United States)

    Yohe, G.R.; Dunbar, J.E.; Pedrotti, R.L.; Scheidt, F.M.; Lee, F.G.H.; Smith, E.C.

    1956-01-01

    The products formed in the oxidation of 2,6-di-tert-butyl-4-methylphenol with oxygen and sodium hydroxide at about 100?? are 3,5-di-tert-butyl-4-hydroxybenzaldehyde, trimethylacetic acid, an acidic compound C14H22O3, and probably 2,6-di-tert-butylbenzoquinone (which was actually isolated in the similar oxidation of the above-named benzaldehyde), in addition to compounds previously reported. Some of the properties of C14H22O3 are given, and the oxidation of it to 2,3-di-tert-butylsuccinic anhydride is described, but assignment of structure is reserved pending the completion of more experimental work.

  4. Polyvinylpolypyrrolidone-Supported Boron Trifluoride; Highly Efficient Catalyst for the Synthesis of N-tert-Butyl Amides

    Directory of Open Access Journals (Sweden)

    Masoud Mokhtary

    2012-01-01

    Full Text Available Highly efficient method for the preparation of N-tert-butyl amides by reaction of nitriles with tert-butyl acetate is described using polyvinylpolypyrrolidone-supported boron trifluoride (PVPP-BF3 at 70°C in good to excellent yields. Selective amidation of benzonitrile in the presence of acetonitrile was also achieved. polyvinylpolypyrrolidone-boron trifluoride complex shows non-corrosive and stable solid catalyst elevated Lewis acid property.

  5. Palladium-catalyzed carbonylative Sonogashira coupling of aryl bromides via tert-butyl isocyanide insertion.

    Science.gov (United States)

    Tang, Ting; Fei, Xiang-Dong; Ge, Zhi-Yuan; Chen, Zhong; Zhu, Yong-Ming; Ji, Shun-Jun

    2013-04-05

    A simple and efficient palladium-catalyzed carbonylative Sonogashira coupling via tert-butyl isocyanide insertion has been developed, which demonstrates the utility of isocyanides in intermolecular C-C bond construction. This methodology provides a novel pathway for the synthesis of alkynyl imines which can undergo simple silica gel catalyzed hydrolysis to afford alkynones. The approach is tolerant of a wide range of substrates and applicable to library synthesis.

  6. Aerobic radical multifunctionalization of alkenes using tert-butyl nitrite and water

    Directory of Open Access Journals (Sweden)

    Daisuke Hirose

    2013-08-01

    Full Text Available Water induces a change in the product of radical multifunctionalization reactions of aliphatic alkenes involving an sp3 C–H functionalization by an 1,5-hydrogen shift using tert-butyl nitrite and molecular oxygen. The reaction without water, reported previously, gives nitrated γ-lactols, whereas the reaction in the presence of water produces 4-hydroxy-5-nitropentyl nitrate or 4-hydroxy-3-nitropentyl nitrate derivatives.

  7. (2-tert-Butyl-5-hydroxymethyl-1,3-dioxan-5-ylmethanol

    Directory of Open Access Journals (Sweden)

    Berenice Vargas

    2012-07-01

    Full Text Available In the title compound, C10H20O4, the dioxane ring adopts a chair conformation. The tert-butyl group occupies an equatorial position, and is staggered with respect to the O atoms of the dioxane ring. In the crystal, molecules are connected by O—H...O hydrogen-bonds into zigzag chains of R44(8 and R22(12 ring motifs that run parallel to the a axis.

  8. Different mechanisms of formation of glutathione-protein mixed disulfides of diamide and tert-butyl hydroperoxide in rat blood.

    Science.gov (United States)

    Di Simplicio, P; Lupis, E; Rossi, R

    1996-03-15

    The mechanisms of glutathione-protein mixed disulfide (GSSP) formation caused by diamide and tert-butyl hydroperoxide were studied in rat blood after in vitro treatment in the 0.3-4 mM dose range. tert-Butyl hydroperoxide formed GSSP, via GSSG, according to the reaction, GSSG + PSH --> GSSP + GSH, whereas diamide reacted first with protein SH groups, giving PS-diamide adducts and then, after reaction with GSH, GSSP. Moreover, after diamide treatment, GSSP patterns were characterized by a much slower or irreversible dose-related return to basal levels in comparison with those observed with tert-butyl hydroperoxide, always reversible. Experiments with purified hemoglobin revealed the existence of a large fraction of protein SH groups which formed GSSP and had a higher reactivity than GSH. Experiments on glucose consumption and role of various erythrocyte enzymes, carried out to explain the inertness of GSSP to reduction after treatment of blood with diamide, were substantially negative. Other tests carried out to confirm the efficiency of the enzymatic machinery of blood samples successively treated with diamide and tert-butyl hydroperoxide, indicated that GSSP performed by diamide was difficult to reduce, whereas those generated by tert-butyl hydroperoxide were reversible as normal. Our results suggest that a fraction of GSSP generated by diamide is different and less susceptible to reduction than that obtained with tert-butyl hydroperoxide.

  9. Tert-butyl alcohol used to fabricate nano-cellulose aerogels via freeze-drying technology

    Science.gov (United States)

    Wang, Xiaoyu; Zhang, Yang; Jiang, Hua; Song, Yuxuan; Zhou, Zhaobing; Zhao, Hua

    2017-06-01

    Aerogel, a highly porous material, is attracting increasing attention owing to low thermal conductivity and high specific surface area. Freeze-drying technology has been employed to produce nano-cellulose aerogels; however, the resultant product has low specific surface areas. Here, a modified approach to prepare nano-cellulose aerogels was reported, which involves tert-butyl alcohol as a solvent. Nano-cellulose aerogels were prepared via a spontaneous gelation fashion using calcium chloride solution, followed by tert-butyl alcohol solvent displacement and freeze drying. Addition of calcium chloride (0.25%) accelerated the physical gelation process. The application of tert-butyl alcohol as a solvent contributed to preservation of gel network. The obtained spherical nano-cellulose aerogels had a shrinkage rate of 5.89%. The specific surface area and average pore size was 164. 9666 m2 g-1 and 10.01 nm, respectively. Additionally, nano-cellulose aerogels had a comparable thermal degradation property when compared to microcrystalline cellulose. These biophysical properties make nano-cellulose aerogels as a promising absorption material.

  10. Red fluorescent materials based on julolidine/chromene with the bulky tert-butyl and trimethylsilyl substituents for organic light-emitting diodes.

    Science.gov (United States)

    Na, Eun Jae; Kim, Hye Jeong; Lee, Kum Hee; Lee, Seok Jae; Kim, Young Kwan; Yoon, Seung Soo

    2014-08-01

    In this work, we designed and synthesized two red emitters 2-(6,8-di-tert-butyl-2-(2-(1,1-dimethyl-7-(trimethylsilyl)-7-((trimethylsilyl)methyl)-1,2,3,5,6,7-hexahydropyrido[3,2,1-ij]quinolin-9-yl)vinyl)-4H-chromen-4-ylidene)malononitrile (Red 1) and 2-(6,8-di-tert-butyl-2-(2-(1,1,7-trimethyl-7-t-butyl)-1,2,3,5,6,7-hexahydropyrido[3,2,1-ij]quinolin-9-yl)vinyl)-4H-chromen-4-ylidene)malononitrile (Red 2). To explore the electro-luminescence properties of these materials, multilayered OLEDs using these materials as dopants in a Alq3 host were fabricated. Particularly, by using Red 1 as a dopant in emitting layer, device 1 showed the luminous and power efficiencies of 0.81 cd/A and 0.43 lm/W at 20 mA/cm2, respectively. The CIE coordinates of this device was (0.65, 0.34) at 7.0 V, which is close to the NTSC standard CIE coordinates of (0.67,0.32) for red emission.

  11. 5-tert-Butyl-2-[5-(5-tert-butyl-1,3-benzoxazol-2-yl-2-thienyl]-1,3-benzoxazole

    Directory of Open Access Journals (Sweden)

    Fang-Fang Jian

    2008-12-01

    Full Text Available The title compound, C26H26N2O2S, was prepared by the reaction of thiophene-2,5-dicarboxylic acid and 2-amino-4-tert-butylphenol. One of the tert-butyl groups is disordered over two conformations, with occupancies of 0.539 (1 and 0.461 (2. The two 1,3-benzoxazole rings are almost planar, with dihedral angles of 0.83 (18 and 1.64 (17° between the five- and six-membered rings. The thiophene ring makes dihedral angles of 21.54 (19 and 4.49 (18° with the planes of the five-membered oxazole rings. The crystal packing is controlled by π–π stacking interactions involving the thiophene and benzene rings, with a centroid–centroid distance of 3.748 (2 Å.

  12. Crystal structure of trans-N,N′-bis(3,5-di-tert-butyl-2-hydroxyphenyloxamide methanol monosolvate

    Directory of Open Access Journals (Sweden)

    Miguel-Ángel Velázquez-Carmona

    2016-07-01

    Full Text Available The here crystallized oxamide was previously characterized as an unsolvated species [Jímenez-Pérez et al. (2000. J. Organomet. Chem. 614–615, 283–293], and is now reported with methanol as a solvent of crystallization, C30H44N2O4·CH3OH, in a different space group. The introduction of the solvent influences neither the molecular symmetry of the oxamide, which remains centrosymmetric, nor the molecular conformation. However, the unsolvated molecule crystallized as an ordered system, while many parts of the solvated crystal are disordered. The hydroxy group in the oxamide is disordered over two chemically equivalent positions, with occupancies 0.696 (4:0.304 (4; one tert-butyl group is disordered by rotation about the C—C bond, and was modelled with three sites for each methyl group, each one with occupancy 1/3. Finally, the methanol solvent, which lies on a twofold axis, is disordered by symmetry. The disorder affecting hydroxy groups and the solvent of crystallization allows the formation of numerous supramolecular motifs using four hydrogen bonds, with N—H and O—H groups as donors and the oxamide and methanol molecule as acceptors.

  13. Kinetic Study of Np(Ⅵ) Reduction With Tert-butyl Hydrazine

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Tert-butyl hydrazine(TBH) is a new salt free reductant, it can effectively reduce Np(Ⅵ) to Np(Ⅴ) but reduce Pu(Ⅳ)very slowly. Further more, it has the highest ratio of rate constant for Np(Ⅵ) reduction to the rate constant for Pu(Ⅳ) reduction in hydrazine derivatives, so it’s a promising reductant to separate Np, Pu effectively,Reduction kinetic study of the reaction in nitric acid is performed by spectrophotometry. The effect of some factors such as concentration of TBH, HNO3, Np(Ⅵ) and temperature on the redox

  14. Synchrotron Photoionization Investigation of the Oxidation of Ethyl tert-Butyl Ether.

    Science.gov (United States)

    Winfough, Matthew; Yao, Rong; Ng, Martin; Catani, Katherine; Meloni, Giovanni

    2017-02-23

    The oxidation of ethyl tert-butyl ether (ETBE), a widely used fuel oxygenated additive, is investigated using Cl atoms as initiators in the presence of oxygen. The reaction is carried out at 293, 550, and 700 K. Reaction products are probed by a multiplexed chemical kinetics photoionization mass spectrometer coupled with the synchrotron radiation produced at the Advanced Light Source (ALS) of the Lawrence Berkeley National Laboratory. Products are identified on the basis of mass-to-charge ratio, ionization energies, and shape of photoionization spectra. Reaction pathways are proposed together with detected primary products.

  15. Alkylation of Hydroquinone with tert-Butyl Alcohol over Bis[(perfluoroalkyl)sulfonyl]imides Supported on MCM-41

    Institute of Scientific and Technical Information of China (English)

    YUAN, Yu-Bin; NIE, Jin; ZHANG, Zheng-Bo; ZHOU, San-Yi

    2006-01-01

    Bis[(perfluoroalkyl)sulfonyl]imides [HN(SO2Rf)2, and Rf represents the perfluorinated alkyl group] supported on MCM-41 were synthesized and characterized by XRD, FTIR, SEM, TGA and N2-adsorption techniques. The supported catalysts, HN(SO2Rf)2/MCM-41, were used as the catalysts for the tert-butylation of hydroquinone (HQ)with tert-butyl alcohol (TBA) in the liquid phase. A high yield (52.0%) of 2-tert-butyl hydroquinone (TBHQ) could be obtained in the presence of 5 mol% HN(SO2C4F9)2/MCM-41 under the optimized reaction conditions and the heterogeneous catalyst could be recycled at least 6 times without substantial loss of activity.

  16. Degradation of tert-butyl formate and its intermediates by an ozone/UV process.

    Science.gov (United States)

    Garoma, Temesgen; Gurol, Mirat D; Thotakura, Lalitha; Osibodu, Olufisayo

    2008-12-01

    In this paper, the oxidation of tert-butyl formate (TBF) in aqueous solution by an ozone/UV process was described. The oxidation process was investigated experimentally in a semibatch reactor. The results of the study indicated that the ozone/UV process was very effective in oxidizing TBF. tert-Butyl alcohol (TBA), hydroxy-iso-butyraldehyde (HiBA), acetone, formaldehyde, and formic acid were identified as major primary intermediates during the oxidation of TBF. About 90% organic carbon balance was obtained indicating that most reaction intermediates have been identified and quantified. Some of the primary intermediates were also oxidized in the ozone/UV system. Accordingly, HiBA, acetone, formaldehyde, and formic acid were the primary intermediates of TBA oxidation. The oxidation of acetone in the ozone/UV system generated formaldehyde, pyruvaldehyde, acetic acid, formic acid as primary intermediates. It was also observed that the reaction intermediates formed during the oxidation of TBF react well in the ozone/UV system and complete mineralization could be achieved by the process.

  17. Ethyl tert-butyl ether (ETBE)-degrading microbial communities in enrichments from polluted environments.

    Science.gov (United States)

    Le Digabel, Yoann; Demanèche, Sandrine; Benoit, Yves; Fayolle-Guichard, Françoise; Vogel, Timothy M

    2014-08-30

    The ethyl tert-butyl ether (ETBE) degradation capacity and phylogenetic composition of five aerobic enrichment cultures with ETBE as the sole carbon and energy source were studied. In all cases, ETBE was entirely degraded to biomass and CO2. Clone libraries of the 16S rRNA gene were prepared from each enrichment. The analyses of the DNA sequences obtained showed different taxonomic compositions with a majority of Proteobacteria in three cases. The two other enrichments have different microbiota with an abundance of Acidobacteria in one case, whereas the microbiota in the second was more diverse (majority of Actinobacteria, Chlorobi and Gemmatimonadetes). Actinobacteria were detected in all five enrichments. Several bacterial strains were isolated from the enrichments and five were capable of degrading ETBE and/or tert-butyl alcohol (TBA), a degradation intermediate. The five included three Rhodococcus sp. (IFP 2040, IFP 2041, IFP 2043), one Betaproteobacteria (IFP 2047) belonging to the Rubrivivax/Leptothrix/Ideonella branch, and one Pseudonocardia sp. (IFP 2050). Quantification of these five strains and two other strains, Rhodococcus sp. IFP 2042 and Bradyrhizobium sp. IFP2049, which had been previously isolated from one of the enrichments was carried out on the different enrichments based on quantitative PCR with specific 16S rRNA gene primers and the results were consistent with the hypothesized role of Actinobacteria and Betaproteobacteria in the degradation of ETBE and the possible role of Bradyrhizobium strains in the degradation of TBA.

  18. 5-tert-Butyl-2-(4'-[{sup 18}F]fluoropropynylphenyl)-1,3-dithiane oxides: potential new GABA{sub A} receptor radioligands

    Energy Technology Data Exchange (ETDEWEB)

    Li Xuehe; Jung, Yong-Woon; Snyder, Scott E.; Blair, Joseph; Sherman, Philip S.; Desmond, Timothy; Frey, Kirk A. [Department of Radiology, University of Michigan Medical School, Ann Arbor, MI 48109 (United States); Kilbourn, Michael R. [Department of Radiology, University of Michigan Medical School, Ann Arbor, MI 48109 (United States)], E-mail: mkilbour@umich.edu

    2008-07-15

    As potential new ligands targeting the binding site of {gamma}-aminobutyric acid (GABA) receptor ionophore, trans-5-tert-butyl-2-(4'-fluoropropynylphenyl)-2-methyl-1,1-dioxo-1, 3-dithiane (1) and cis/trans-5-tert-butyl-2-(4'-fluoropropynylphenyl)-2-methyl-1,1,3, 3-tetroxo-1,3-dithiane (2) were selected for radiolabeling and initial evaluation as in vivo imaging agents for positron emission tomography (PET). Both compounds exhibited identical high in vitro binding affinities (K{sub i}=6.5 nM). Appropriate tosylate-substituted ethynyl precursors were prepared by multistep syntheses involving stepwise sulfur oxidation and chromatographic isolation of desired trans isomers. Radiolabeling was accomplished in one step using nucleophilic [{sup 18}F]fluorination. In vivo biodistribution studies with trans-[{sup 18}F]1 and trans-[{sup 18}F]2 showed significant initial uptake into mouse brain and gradual washout, with heterogeneous regional brain distributions and higher retention in the cerebral cortex and cerebellum and lower retention in the striatum and pons-medulla. These regional distributions of the new radioligands correlated with in vitro and ex vivo measures of standard radioligands binding to the ionophore- and benzodiazepine-binding sites of GABA{sub A} receptor in rodent brain. A comparison of these results with previously prepared radiotracers for other neurochemical targets, including successes and failures as in vivo radioligands, suggests that higher-affinity compounds with increased retention in target brain tissues will likely be needed before a successful radiopharmaceutical for human PET imaging can be identified.

  19. Crystal structure of 2-tert-butyl-1,3-thiazolo[4,5-b]pyridine

    Directory of Open Access Journals (Sweden)

    Gamal A. El-Hiti

    2014-09-01

    Full Text Available The title compound, C10H12N2S, does not contain any strong hydrogen-bond donors but two long C—H...N contacts are observed in the crystal structure, with the most linear interaction linking molecules along [010]. The ellipsoids of the tert-butyl group indicate large librational motion.

  20. [A rapid gas chromatographic method for determination of P-tert-butyl toluene in the air of workplace].

    Science.gov (United States)

    Chen, Wei; Liu, Guihua; Lin, Kai; He, Cai; Zhong, Yuetong

    2012-05-01

    To establish a rapid gas chromatographic method for determination of P-tert-Butyl toluene in the air of workplace. The air samples were collected by syringes, injected directly to the GC system, and then separated by a FFAP capillary column (30m x 0.53mm x 0.25 microm), finally determined by a Flame Ionization Detector. This method showed good linear correlation within a range of 0 - 320 microg/ml, with regression formula Y = 26437 + 4836X, r = 0.9994. The air sample could be stably stored in the syringe for 5 hours. The relative standard deviation (RSD) of repeated injection of P-tert-butyl toluene standard solutions at three concentration levels by six times was 0.65% - 1.98%. The minimum detectable concentration was calculated to be 1.12 mg/m3. Other volative organic solvents, e. g., M-tert-butyltoluene, ethyl acetate, methylethyl ketone, O-tert-butyl toluene, toluene, O-xylene are not interferences. This method meets the requirement of "Guide for establishing occupational health standards--Part 4: Determination methods of air chemicals in workplace". It is applicable for determination of P-tert-butyl toluene in the air of workplace.

  1. Quercetin protects human hepatoma HepG2 against oxidative stress induced by tert-butyl hydroperoxide.

    Science.gov (United States)

    Alía, Mario; Ramos, Sonia; Mateos, Raquel; Granado-Serrano, Ana Belén; Bravo, Laura; Goya, Luis

    2006-04-15

    Flavonols such as quercetin, have been reported to exhibit a wide range of biological activities related to their antioxidant capacity. The objective of the present study was to investigate the protective effect of quercetin on cell viability and redox status of cultured HepG2 cells submitted to oxidative stress induced by tert-butyl hydroperoxide. Concentrations of reduced glutathione and malondialdehyde, generation of reactive oxygen species and activity and gene expression of antioxidant enzymes were used as markers of cellular oxidative status. Pretreatment of HepG2 with 10 microM quercetin completely prevented lactate dehydrogenase leakage from the cells. Pretreatment for 2 or 20 h with all doses of quercetin (0.1-10 microM) prevented the decrease of reduced glutathione and the increase of malondialdehyde evoked by tert-butyl hydroperoxide in HepG2 cells. Reactive oxygen species generation induced by tert-butyl hydroperoxide was significantly reduced when cells were pretreated for 2 or 20 h with 10 microM and for 20 h with 5 microM quercetin. Finally, some of the quercetin treatments prevented the significant increase of glutathione peroxidase, superoxide dismutase, glutathione reductase and catalase activities induced by tert-butyl hydroperoxide. Gene expression of antioxidant enzymes was also affected by the treatment with the polyphenol. The results of the biomarkers analyzed clearly show that treatment of HepG2 cells in culture with the natural dietary antioxidant quercetin strongly protects the cells against an oxidative insult.

  2. (2-tert-Butyl-3-phenyl-2,3-dihydroisoxazole-4,5-diylbis(phenylmethanone

    Directory of Open Access Journals (Sweden)

    M. R. Prathapachandra Kurup

    2013-08-01

    Full Text Available The phenyl and tert-butyl groups of the title compound, C27H25NO3, exhibit a trans configuration in agreement with the stereochemistry of the Z phenyl-N-tert-butylnitrone starting material. The attached carbonyl groups are not coplanar with the neighboring dihydroisoxazole ring and the phenyl rings they are bonded to, with torsion angles of 59.26 (8, 17.53 (11, 16.52 (12 and 52.86 (7°. The dihedral angle between the dihydroisoxazole ring and the directly attached phenyl group is 86.86 (8°. There are two nonclassical intermolecular C—H...O hydrogen-bonding interactions that operate together with an intermolecular C—H...π interaction to form a supramolecular architecture in the crystal system.

  3. Structure-activity relationships for insect growth regulators derived from substituted di-tert-butyl phenols

    Energy Technology Data Exchange (ETDEWEB)

    Walton, B.T.; Sanborn, J.R.; Metcalf, R.L.

    1979-01-01

    Thirty-six para-substituted derivatives of 2,6-di-tert-butyl phenols were synthesized and tested for toxicity to fourth instar larvae of the mosquito Culex quinquefasciatus Say. Toxicities of these compounds ranged from an LC/sub 50/ of 0.004 ppM to LC/sub 50/ > 10 ppM. Mosquitoes treated with toxic analogues characteristically died shortly after the pupal molt and appeared to be morphologically normal, untanned pupae. Correlations of insecticidal activity with physicochemical parameters of the para-substituent was found to explain 71.82% of the variation in insecticidal activity expressed as log LC/sub 50/(mM).

  4. The fate of the tert-butyl radical in low-temperature autoignition reactions

    Science.gov (United States)

    Moore, Kevin B.; Turney, Justin M.; Schaefer, Henry F.

    2017-05-01

    Alkyl combustion models depend on kinetic parameters derived from reliable experimental or theoretical energetics that are often unavailable for larger species. To this end, we have performed a comprehensive investigation of the tert-butyl radical (R• in this paper) autoignition pathways. CCSD(T)/ANO0 geometries and harmonic vibrational frequencies were obtained for key stationary points for the R• + O2 and QOOH + O2 mechanisms. Relative energies were computed to chemical accuracy (±1 kcalmol-1) via extrapolation of RCCSD(T) energies to the complete basis-set limit, or usage of RCCSD(T)-F12 methods. At 0 K, the minimum energy R• + O2 pathway involves direct elimination of HO2• (30.3 kcal mol-1 barrier) from the tert-butyl peroxy radical (ROO•) to give isobutene. This pathway lies well below the competing QOOH-forming intramolecular hydrogen abstraction pathway (36.2 kcalmol-1 barrier) and ROO• dissociation (35.9 kcalmol-1 barrier). The most favorable decomposition channel for QOOH radicals leads to isobutene oxide (12.0 kcalmol-1 barrier) over isobutene (18.6 kcalmol-1 barrier). For the QOOH + O2 pathways, we studied the transition states and initial products along three pathways: (1) α-hydrogen abstraction (42.0 kcalmol-1 barrier), (2) γ-hydrogen abstraction (27.0 kcalmol-1 barrier), and (3) hydrogen transfer to the peroxy moiety (24.4 kcalmol-1 barrier). The barrier is an extensive modification to the previous 18.7 kcalmol-1 value and warrants further study. However, it is still likely that the lowest energy QOOH + O2 pathway corresponds to pathway (3). We found significant spin contamination and/or multireference character in multiple stationary points, especially for transition states stemming from QOOH. Lastly, we provide evidence for an A˜ -X˜ surface crossing at a Cs-symmetric, intramolecular hydrogen abstraction structure.

  5. 5,11,17,23-Tetra-tert-butyl-25,26,27,28-tetramethoxycalix[4]arene dichloromethane hemisolvate

    Directory of Open Access Journals (Sweden)

    Edwin Weber

    2008-04-01

    Full Text Available In the title compound, C48H64O4·0.5CH2Cl2, both crystallographically independent calixarene molecules display a partial cone conformation. Their crystal packing is stabilized by C—H...π contacts involving the methoxy groups. The solvent molecule is located interstitially between two calixarene units with C—H...Cl contacts to methoxy and tert-butyl groups. One tert-butyl residue of each calixarene molecule is disordered over two positions (occupancies 0.60/0.40 and 0.63/0.37, resulting in bond distances that deviate from ideal values. The tetramer calixarene molecules present models with approximate non-crystallographic Cs symmetry.

  6. Optimizing the Synthesis of Ethyl tert-Butyl Ether in Continuous Catalytic Distillation Column Using New Ion Exchange Resin Catalyst

    Institute of Scientific and Technical Information of China (English)

    Muhammad Umar; Yahia Abubakar Al-Hamed; Abdulraheem Al-Zahrani; Hisham Saeed Bamufleh

    2013-01-01

    Liquid phase synthesis of one of the important fuel oxygenate, ethyl tert-butyl ether (ETBE), from etha-nol and tert-butyl alcohol (TBA) has been studied in catalytic distillation column (CDC) using ion exchange resin catalyst CT-145H. A packed CDC of 1.2 m height and 50 mm diameter with indigenously developed reactive sec-tion packing was used to generate experimental data. Effect of different key variables on product purity in distillate, was investigated to find the optimum operating conditions for ETBE synthesis. The optimum conditions for 0.2 kg·s-1 of ethanol feed were found:reboiler duty of 375 W, molar feed ratio of 1︰1.3 of reactants, and reflux ratio of 7. Concentration profiles for each component along each column section at optimum conditions were also drawn. Neither output nor input multiplicity was observed at experimental conditions.

  7. Is the tert-butyl group bulky enough to end-cap a pseudorotaxane with a 24-crown-8-ether wheel?

    Science.gov (United States)

    Tachibana, Yuya; Kihara, Nobuhiro; Furusho, Yoshio; Takata, Toshikazu

    2004-11-25

    Although rotaxane chemists have long believed that the tert-butyl group is bulkier than the cavity of dibenzo-24-crown-8-ether (DB24C8), it is essentially smaller than the cavity of DB24C8. The tert-butyl (or 4-tert-butylphenyl) group can actually function as an end-cap of DB24C8-based rotaxanes when the intercomponent interaction is effectively operative. When such attractive interaction is removed, deslippage occurs. [structure: see text

  8. (2S,4S-3-Benzoyl-4-benzyl-2-tert-butyl-1,3-oxazolidin-5-one

    Directory of Open Access Journals (Sweden)

    Victoria J. Dungan

    2012-09-01

    Full Text Available In the title compound, C21H23NO3, the central oxazolidinone ring is approximately planar, the maximum deviation from the plane through the central ring being 0.043 (1 Å. The tert-butyl and benzyl substituents are cis to each other and trans to the N-benzoyl group. The interplanar angle between the aromatic rings of the C-benzyl and N-benzoyl groups is 81.10 (4°.

  9. Molecular structure and spectral investigations of 3,5-Di-tert-butyl-o-benzoquinone

    Science.gov (United States)

    Yilmaz, M.; Aydin, B.; Dogan, O.; Dereli, O.

    2017-01-01

    Conformational analysis of 3,5-Di-tert-butyl-o-benzoquinone molecule was performed and two stable conformers were determined by B3LYP/6-311++G(d,p). Using the most stable one, molecular structural parameters, vibrational frequencies were calculated by B3LYP/6-311++G(d,p), B3LYP/6-31G(d) and BLYP/6-31G(d,p) levels of theory. The FT-IR spectrum of the compound was recorded in the region 4000-550 cm-1. The Raman spectrum was also recorded in the region 3500-100 cm-1. Calculated results were compared with experimental counterparts. The best results were obtained from B3LYP/6-311++G(d,p) calculations. Experimental 13C and 1H NMR data of tittle compound were taken from literature and the calculated results compared with these data. Vibrational and NMR band assignments were performed. HOMO-LUMO energies, molecular electrostatic potentials and thermodynamic properties were also given for further investigations of our structure.

  10. Coverage dependent isomerisation behaviour of tetra-tert-butyl-imine on Au(111)

    Energy Technology Data Exchange (ETDEWEB)

    Leyssner, Felix; Koch, Matthias; Meyer, Stephan; Tegeder, Petra [Freie Universitaet Berlin, Fachbereich Physik, Arnimallee 14, D-14195 Berlin (Germany)

    2011-07-01

    High resolution electron energy loss spectroscopy (HREELS) is employed to analyze thermally activated changes in the geometrical structure of the photochromic molecular switch 3,3',5,5'-tetra-tert-butyl-imine (TBI) adsorbed on Au(111). Measurements have been performed for two coverage regimes: The monolayer and the bilayer regime. For both coverages all molecules are found in the trans state after deposition at sample temperatures of T=210 K, but conformational changes upon heating are observed, which are assigned to a trans to cis-isomerization. When heating the sample to T=440 K two different conformations are observed depending on the initial coverage. Annealing of a monolayer leads to an increasing number of cis isomers, pointing towards an inverted thermal isomerisation behaviour of TBI, since the trans-isomer is the more stable compound in solution. Whereas for a bilayer the temperature induced isomerization of the TBI can be monitored as well, but desorption of the second layer at T=440 K leads to the formation of a trans-monolayer. The fact that different molecular configurations are found for equal coverages annealed at the same temperature is highly surprising and shows that collective effects may govern the switching properties of molecular switches on surfaces.

  11. Effect of tert-butyl hydroperoxide addition on spontaneous chemiluminescence in brain.

    Science.gov (United States)

    Azorin, I; Bella, M C; Iborra, F J; Fornas, E; Renau-Piqueras, J

    1995-12-01

    It is well known that light emission is related to lipid peroxidation in biological material, and that this process occurs spontaneously in the brain. tert-Butyl hydroperoxide (tBHP) is an organic peroxide widely used as initiator of free radical production in several biological systems. However, the prooxidant capacity of this compound remins unclear. To clarify its role in brain spontaneous autooxidation, rat brain homogenates were incubated with and without tBHP. Light emission and lipid peroxidation were measured by luminometry and the TBARs test, respectively. Several inhibitors of free radical-induced lipid peroxidation were also used. These inhibitors included ascorbate, EDTA, and desferrioxamine. Our results indicate that the pattern of light emission spontaneously produced in brain was different from that observed after the addition of tBHP to the homogenates, and that these differences depended on the tBHP concentration. The main difference was that tBHP caused a rapid light emission that reached its maximum more quickly than in the case of spontaneous emission. Addition of ascorbate resulted in an increase in chemiluminescence in presence of tBHP. In contrast, EDTA and desferrioxamine inhibited light emission in homogenates both with and without tBHP. The results of MDA determination were similar to those described, including the effect of inhibitors. A common feature in MDA and luminometric determinations was the dispersion of data. In conclusion, these results suggest that tBHP, under specific conditions, modify the kinetic pattern of brain spontaneous autooxidation.

  12. Experimental investigation of incremental reactivity of di-tert-butyl peroxide

    Institute of Scientific and Technical Information of China (English)

    DU Lin; XU YongFu; GE MaoFa; JIA Long; YAO Li

    2007-01-01

    Large quantities of di-tert-butyl peroxide(DTBP)have been emitted into the troposphere due to human activities.Its role in the atmospheric photochemical reaction has not been understood.This study presents the results of the photochemical reactions of DTBP and NOx,which have been simulated in a self-made smog chamber under the temperature of(29±1)℃.Both the wall decays of ozone and NO2 could be neglected,compared to the results in simulative experiments.The effective intensity of UV light used in the experiments was 1.28x10-3s-1,which was expressed by the rate constant of NO2 photolysis in purified air.The reaction mechanism was proposed according to our results and reports of other researchers.The maximum values of incremental reactivity(IR)in the three simulative experiments were 9.53x10-2,5.23x10-2 and 3.78x10-2,respectively.The incremental reactivity decreased with the increase of initial concentrations of DTBP.The IR value of DTBP obtained in this study was comparable to that of acetylene reported in our previous research.

  13. Crystal structure of 5-tert-butyl-10,15,20-triphenylporphyrin

    Directory of Open Access Journals (Sweden)

    Keith J. Flanagan

    2016-02-01

    Full Text Available In the title free base porphyrin, C42H34N4, the neighbouring N...N distances in the center of the ring vary from 2.818 (8 to 2.998 (8 Å and the phenyl rings are tilted from the 24-atom mean plane at angles varying between 62.42 (2–71.63 (2°. The NH groups are involved in intramolecular bifurcated N—H...(N,N hydrogen bonds. The Ca—Cm—Ca angles vary slightly for the phenyl rings, between 124.19 (18–126.17 (18°. The largest deviation from the mean plane of the 24-atom macrocycle is associated with the meso carbon at the substituted tert-butyl position, which is displaced from the mean plane by 0.44 (2 Å. The free base porphyrin is characterized by a significant degree of ruffled (B1u distortion with contributions from domed (A2u and wave [Eg(y and Eg(x] modes. In the crystal, molecules are linked by a number of weak C—H...π interactions, forming a three-dimensional framework. The structure was refined as a two-component inversion twin.

  14. Venting Design for Di-tert-butyl Peroxide Runaway Reaction Based on Accelerating Rate Calorimeter Test

    Institute of Scientific and Technical Information of China (English)

    魏彤彤; 蒋慧灵

    2012-01-01

    In order to design the relief system size of di-tert-butyl peroxide(DTBP) storage tanks,the runaway re-action of DTBP was simulated by accelerating rate calorimeter(ARC).The results indicated that under adiabatic conditions the initial exothermic temperature was 102.6 ℃,the maximum self-heating rate was 3.095×107 ℃·min-1,the maximum self-heating temperature was 375.9 ℃,and the pressure produced by unit mass was 4.512 MPa·g-1.Judged by ARC test,the emergency relief system for DTBP was a hybrid system.Based on Design Institute for Emergency Relief System(DIERS) method,the releasing mass flow rate W was determined by Leung methods,and the mass velocity G was calculated by two modified Omega methods.The two relief sizes calculated by monograph Omega method and arithmetic Omega method are close,with only 0.63% relative error.The monograph Omega method is more convenient to apply.

  15. Predicted and experimental crystal structures of ethyl-tert-butyl ether.

    Science.gov (United States)

    Hammer, Sonja M; Alig, Edith; Fink, Lothar; Schmidt, Martin U

    2011-04-01

    Possible crystal structures of ethyl-tert-butyl ether (ETBE) were predicted by global lattice-energy minimizations using the force-field approach. 33 structures were found within an energy range of 2 kJmol(-1) above the global minimum. Low-temperature crystallization experiments were carried out at 80-160 K. The crystal structure was determined from X-ray powder data. ETBE crystallizes in C2/m, Z = 4, with molecules on mirror planes. The ETBE molecule adopts a trans conformation with a (CH(3))(3)C-O-C-C torsion angle of 180°. The experimental structure corresponds with high accuracy to the predicted structure with energy rank 2, which has an energy of 0.54 kJmol(-1) above the global minimum and is the most dense low-energy structure. In some crystallization experiments a second polymorph was observed, but the quality of the powder data did not allow the determination of the crystal structure. Possibilities and limitations are discussed for solving crystal structures from powder diffraction data by real-space methods and lattice-energy minimizations.

  16. Molecular structures of tris(1-tert-butyl-2-mercaptoimidazolyl)hydroborate complexes of titanium, zirconium and hafnium.

    Science.gov (United States)

    Rong, Yi; Sambade, David; Parkin, Gerard

    2016-11-01

    Cyclopentadienyl and tris(pyrazolyl)hydroborate have found much use as supporting ligands in the chemistry of titanium, zirconium and hafnium, especially with respect to applications involving olefin polymerization catalysis. In contrast, closely related tris(1-alkyl-2-mercaptoimidazolyl)hydroborate, [Tm(R)], ligands have so far found little application to the chemistry of these elements, despite the fact that such ligands are currently used extensively in coordination chemistry. In view of the fact that a substituent in the 2-position exerts a direct influence on the steric environment of the metal center, we report here the application of the sterically demanding tris(1-tert-butyl-2-mercaptoimidazolyl)hydroborate [Tm(t-Bu)] ligand to these metals. Dichlorido(η(5)-cyclopentadienyl)[tris(1-tert-butyl-2-sulfanylidene-2,3-dihydro-1H-imidazol-3-yl)borato-κ(3)S,S',H]zirconium(IV) benzene hemisolvate, [Zr(C21H34BN6S3)(C5H5)Cl2]·0.5C6H6, (I), dichlorido(η(5)-cyclopentadienyl)[tris(1-tert-butyl-2-sulfanylidene-2,3-dihydro-1H-imidazol-3-yl)borato-κ(3)S,S',H]titanium(IV) benzene hemisolvate, [Ti(C21H34BN6S3)(C5H5)Cl2]·0.5C6H6, (II), [bis(1-tert-butyl-2-sulfanylidene-2,3-dihydro-1H-imidazol-3-yl)borato-κ(3)S,S',H]dichlorido(η(5)-cyclopentadienyl)zirconium(IV), [Zr(C14H24BN4S2)(C5H5)Cl2], (III), (1-tert-butyl-2,3-dihydro-1H-imidazole-2-thione-κS)(1-tert-butyl-2-sulfanylidene-1H-imidazol-3-ido-κ(2)N(3),S)dichlorido(η(5)-cyclopentadienyl)zirconium(IV) benzene monosolvate, [Zr(C7H11N2S)(C7H12N2S)(C5H5)Cl2]·C6H6, (IV), and tribenzyl[tris(1-tert-butyl-2-sulfanylidene-2,3-dihydro-1H-imidazol-3-yl)borato-κ(3)S,S',S'']hafnium(IV) benzene tetrasolvate, [Hf(C7H7)3(C21H34BN6S3)]·4C6H6, (V), have been structurally characterized by X-ray diffraction. The [Tm(t-Bu)] ligand coordinates to Ti and Zr in Cp[κ(3)S2,H-Tm(t-Bu)]MCl2 [M = Zr, (I), and Ti, (II)] in a κ(3)S2,H mode, while the benzyl compounds [Tm(t-Bu)]M(CH2Ph)3 [M = Zr and Hf, (V)] exhibit κ(3)S3 coordination.

  17. tert-Butyl hydroperoxide oxygenation of organic sulfides catalyzed by diruthenium(II,III) tetracarboxylates.

    Science.gov (United States)

    Villalobos, Leslie; Barker Paredes, Julia E; Cao, Zhi; Ren, Tong

    2013-11-04

    Diruthenium(II,III) carboxylates Ru2(esp)2Cl (1a), [Ru2(esp)2(H2O)2]BF4 (1b), and Ru2(OAc)4Cl (2) efficiently catalyze the oxygenation of organic sulfides. As noted in a previous work, 1a is active in oxygenation of organic sulfides with tert-butyl hydroperoxide (TBHP) in CH3CN. Reported herein in detail is the oxygenation activity of 1a, 1b, and 2, with the latter being highly selective in oxo-transfer to organic sulfides using TBHP under ambient conditions. Solvent-free oxidation reactions were achieved through dissolving 1a or 1b directly into the substrate with 2 equiv of TBHP, yielding TOF up to 2056 h(-1) with 1b. Also examined are the rate dependence on both catalyst and oxidant concentration for reactions with catalysts 1a and 2. Ru2(OAc)4Cl may be kinetically saturated with TBHP; however, Ru2(esp)2Cl does not display saturation kinetics. By use of a series of para-substituted thioanisoles, linear free-energy relationships were established for both 1a and 2, where the reactivity constants (ρ) are negative and that of 1a is about half that of 2. Given these reactivity data, two plausible reaction pathways were suggested. Density functional theory (DFT) calculation for the model compound Ru2(OAc)4Cl·TBHP, with TBHP on the open axial site, revealed elongation of the O-O bond of TBHP upon coordination.

  18. Ascorbate protects against tert-butyl hydroperoxide inhibition of erythrocyte membrane Ca2+ + Mg2(+)-ATPase.

    Science.gov (United States)

    Moore, R B; Bamberg, A D; Wilson, L C; Jenkins, L D; Mankad, V N

    1990-05-01

    The incubation of erythrocyte suspensions or isolated membranes containing a residual amount of hemoglobin (0.04% of original cellular hemoglobin) with tert-butyl hydroperoxide (tBHP, 0.5 mM) caused significant inhibition of basal and calmodulin-stimulated Ca2+ + Mg2(+)-ATPase activities and the formation of thiobarbituric acid reactive products measured as malondialdehyde. In contrast, the treatment of white ghosts (membranes not containing hemoglobin) with tBHP (0.5 mM) did not lead to appreciable enzyme inhibition within the first 20 min and did not result in malondialdehyde (MDA) formation. However, the addition of either 10 microM hemin or 100 microM ferrous chloride + 1 mM ADP to white ghosts produced hydroperoxide effects similar to those in pink ghosts (membranes with 0.04% hemoglobin). The concentrations of hemin and ferrous chloride which caused half-maximal inhibition of Ca2+ + Mg2(+)-ATPase activity at 10 min were 0.5 and 30 microM, respectively. The effects of several antioxidants (mannitol, thiourea, hydroxyurea, butylated hydroxytoluene, and ascorbate) were investigated for their protective effects against oxidative changes resulting from tBHP treatment. Over a 30-min incubation period only ascorbate significantly reduced the enzyme inhibition, MDA formation, and protein polymerization. Thiourea and hydroxyurea decreased MDA formation and protein polymerization but failed to protect against the enzyme inhibition. Butylated hydroxytoluene was similar to thiourea and hydroxyurea but with better protection at 10 min. Mannitol, under these conditions, was an ineffective antioxidant for all parameters tested.

  19. tert-Butyl 3-(3-methyl-1-oxidopyridin-1-ium-2-ylbenzoate

    Directory of Open Access Journals (Sweden)

    Gerhard Laus

    2016-01-01

    Full Text Available In the title compound, C17H19NO3, which was obtained by oxidation of the corresponding pyridine derivative, the dihedral angle between the benzene and the pyridine rings is 68.2 (1°. In the crystal, C—H...O hydrogen bonds to carboxyl and N-oxide O-atom acceptors gives a cyclic dimer substructure with an R22(18 motif which is extended into a undulating sheet structure lying parallel to (100 through weak C—H...Ooxide hydrogen bonds. Also present are π–π ring interactions [ring centroid separation = 3.561 (2 Å].

  20. TRANSPORT OF METHYL TERT-BUTYL ETHER THROUGH ALFALFA PLANTS. (R825549C062)

    Science.gov (United States)

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  1. TRANSPORT OF METHYL TERT-BUTYL ETHER THROUGH ALFALFA PLANTS. (R825549C062)

    Science.gov (United States)

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  2. tert-Butyl N-{4-methyl-3-[4-(3-pyridylpyrimidin-2-yloxy]phenyl}carbamate

    Directory of Open Access Journals (Sweden)

    Shi-Gui Tang

    2009-08-01

    Full Text Available In the molecule of the title compound, C21H22N4O3, the pyrimidine ring is oriented at dihedral angles of 0.51 (3 and 50.76 (3° to the pyridine and benzene rings, respectively. In the crystal structure, intermolecular N—H...N hydrogen bonds link the molecules into centrosymmetric dimers, forming R22(24 ring motifs; the dimers are linked by intermolecular C—H...O hydrogen bonds into a two-dimensional network. π–π contacts between the benzene rings and between the pyrimidine and pyridine rings [centroid–centroid distances = 3.891 (1 and 3.646 (1 Å, respectively] may further stabilize the structure. Two weak C—H...π interactions are also present.

  3. Response of the antioxidant defense system to tert-butyl hydroperoxide and hydrogen peroxide in a human hepatoma cell line (HepG2).

    Science.gov (United States)

    Alía, Mario; Ramos, Sonia; Mateos, Raquel; Bravo, Laura; Goya, Luis

    2005-01-01

    The aim of this work was to investigate the response of the antioxidant defense system to two oxidative stressors, hydrogen peroxide and tert-butyl hydroperoxide, in HepG2 cells in culture. The parameters evaluated included enzyme activity and gene expression of superoxide dismutase, catalase, glutathione peroxidase, and activity of glutathione reductase. Besides, markers of the cell damage and oxidative stress evoked by the stressors such as cell viability, intracellular reactive oxygen species generation, malondialdehyde levels, and reduced glutathione concentration were evaluated. Both stressors, hydrogen peroxide and tert-butyl hydroperoxide, enhanced cell damage and reactive oxygen species generation at doses above 50 microM. The concentration of reduced glutathione decreased, and levels of malondialdehyde and activity of the antioxidant enzymes consistently increased only when HepG2 cells were treated with tert-butyl hydroperoxide but not when hydrogen peroxide was used. A slight increase in the gene expression of Cu/Zn superoxide dismutase and catalase with 500 microM tert-butyl hydroperoxide and of catalase with 200 microM hydrogen peroxide was observed. The response of the components of the antioxidant defense system evaluated in this study indicates that tert-butyl hydroperoxide evokes a consistent cellular stress in HepG2.

  4. Red fluorescent emitting materials based on di-tert-butyl chromene derivatives for organic light-emitting diodes.

    Science.gov (United States)

    Na, Eun Jae; Lee, Kum Hee; Han, Hoon; Kim, Young Kwan; Yoon, Seung Soo

    2013-01-01

    In this paper are described two di-tert-butyl chromene-containing red fluorescent materials (Red 1 and Red 2). To explore the electroluminescence properties of these materials, multilayered OLEDs using these materials as dopants in a Alq3 host were fabricated. In particular, a device using Red 2 as the dopant material showed maximum luminous efficiencies and power efficiencies of 1.14 cd/A and 0.58 Im/W, respectively. The CIEx,y coordinates of this device were (0.67, 0.32) at 7.0 V.

  5. HYDROLYSIS TRANSFORMATION OF A POLYSTYRENE-b-POLY(tert-BUTYL ACRYLATE)COPOLYMER AND MICELLIZATION PROPERTIES OF THE HYDROLYZED COPOLYMER

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A very mild and extremely efficient hydrolysis method for transformation of polystyrene-b-poly(tert-butyl acrylate) (PS-b-PtBA) to polystyrene-b-poly(acrylic acid) (PS-b-PAA)was designed and carried out using more convenient and inexpensive chlorotrimethylsilane/sodium iodide as reagents. The hydrolysis product can self-assemble in aqueous media to give regular micelles with PS block forming the core and PAL4 block forming the corona, or in tetrahydrofuran (THF) to give reverse micelles with the hydrophilic block in the core.

  6. tert-Butyl N-[6-(N,N-dipropylcarbamoyl-1,3-benzothiazol-2-yl]carbamate

    Directory of Open Access Journals (Sweden)

    Xin Fang

    2010-05-01

    Full Text Available The title compound C19H27N3O3S, crystallizes with two unique molecules in the asymmetric unit. The benzene ring of each benzothiazole unit carries a dipropylcarbamoyl substituent in the 6-position and a tert-butyl carbamate unit on each thiazole ring. In the crystal structure, intermolecular N—H...N and weak C—H...O hydrogen bonds form centrosymmetric dimers. Additional C—H...O contacts construct a three-dimensional network. A very weak C—H...π contact is also present.

  7. Effect of beta-radiation or oxidising agents on 3,5-di-tert, butyl-4-hydroxytoluene

    Energy Technology Data Exchange (ETDEWEB)

    Majcherczyk, C.; Polge, P.; Baylocq, D.; Pellerin, F.

    1986-12-01

    An HPLC method for the identification and determination of BHT (3,5-di-tert.butyl-4-hydroxytoluene) and the by-products obtained from it by ..beta..-ray or oxidative treatment is described. The chemical structure of the by-products is established by mass spectrometry. The irradiation leads to the dimeric and trimeric forms of the antioxidant and the oxidation to a cyclohexa-2,5-dien-l-one with substitution of a hydroxy and a methanol or aldehyde group at position 4.

  8. 甲苯与叔丁醇在补铝HM沸石催化剂上的烷基化反应%Tert-butylation of toluene with tert-butyl alcohol over realuminated H-mordenite zeolite

    Institute of Scientific and Technical Information of China (English)

    周志伟; 武文良; 王军; 曾崇余

    2009-01-01

    The realuminated H-mordenite catalysts(HM1-4)treated with difirerent concentrations of NaOH and NaAlO2 aqueous solutions were prepared,and characterized by inductively coupled plasma(ICP),X-ray diffraction (XRD),Fourier transform-infrared spectroscopy(FT-I R)and temperature-programmed desorption of ammonia,They are of lower Si/Al ratio and higher acid amount while keeping a high relative crystallinity.Their catalytic performances were evaluated with the liquid-phase tert-butylation of toluene with tert-butyl alcohol in a 100 ml stainless steel batch reactor equipped with a stirrer.HM2 zeolite catalyst,obtained by treating HM in 0.1 mol.L-1 NaOH followed bv 0.05 mol.L-1 NaAIO2 aqueous solution,shows a higher catalytic activity because of its highest acid amount.For HM2 catalyst the influcnces of reaction conditions on catalytic perfclrmance were investigated.The conversion of toluene iS 50.3%and the selectivity of p-tert-butyrltoluene is 74.7%at a temperature of 180°C,2 of molar ratio of tert-butyI alcohol to toluene.4h of reaction time and 0.2 of M(catalyst)/M(toluene).

  9. Catalytic Synthesis of Tert-Butyl Acetate by Nd2O3/Al2O3-Nd2O3/ZnO

    Institute of Scientific and Technical Information of China (English)

    Wang Yajun; Han Limin; A Shan

    2007-01-01

    Nd2O3 was used to support Al2O3 and ZnO to prepare a supported solid base catalyst and investigate the effect of catalyst and reaction conditions on the synthesis of tert-butyl acetate. The composited oxide of Nd2O3/Al2O3-Nd2O3/ZnO exhibited excellent catalytic activity for the synthsis of tert-butyl acetate. The molar ratio of tert-butanol to acetic anhydride is 3:1, the catalyst in total amount of reactant nearly 0.5%, and reaction time 6 h. With the above conditions, yield of the reaction could reach to 65%. The structure of product were verified by the FT-IR, Element analysis, and MS, which proved that the product was tert-butyl acetate.

  10. Syntheses, properties, and reactions of transition metal complexes of di(tert-butyl)amide and 2,2,6,6-tetramethylpiperidide

    Science.gov (United States)

    Davis, Luke M.

    nitride. The XPS binding energies confirm that the nitrogen is present as nitride in all cases. The M:N ratio in the deposited films decreases from Mn (2.5) to Fe (4) to Co (4.6-6) to Ni (9). Carbon contamination in the films is minimal for the manganese, iron, and cobalt nitride films, but similar to the nitrogen content in the nickel nitride films. Comparing the growth onset temperatures with the decomposition temperatures of the compounds M(NH2)2 supports the intermediacy in the film growth of the latter species, which are the expected products of the transamination of M[N(t-Bu)2]2 compounds with NH3. Treatment of MnBr2(thf)2, FeBr2(dme), and CoBr2(dme) with two equivalents of lithium 2,2,6,6-tetramethylpiperidide, Li(tmp), in pentane, followed by sublimation in static vacuum, affords the new compounds M(tmp)2 (M = Mn, Fe, Co). The heteroleptic, dinuclear three-coordinate compounds Fe2(tmp)3(OEt) and [Li(dme)][CoBr(tmp)2] have also been isolated. Crystallographic studies of Fe(tmp)2 demonstrate that the tmp ligand, which is the cyclic analogue of di(tert-butyl)amide with a slightly compressed C-N-C angle, can also enforce two-coordination. The Fe-N bonds are similar to those in the linear compound Fe[N(t-Bu)2]2, although the N-Fe-N angle of 173° and ligand dihedral angle of 73° are smaller. Fe(tmp)2 might therefore be expected to have a less degenerate ground state. Treatment of TiCl4 with two equivalents of H(tmp) affords the new compound Ti2Cl6(tmp)2. In contrast, treatment of TiCl4 or TiCl4(thf)2 with three equivalents of Li(tmp) induces ring-opening dealkylation of one tmp ligand and formation of a 1,1,5-trimethyl-5-hexenylimido ligand. A similar reaction is known for the di(tert-butyl)amido ligand.We conclude that the synthesis of early transition metal tmp and di(tert-butyl)amide compounds is hampered by the high electropositivity of these metals, which activates the methyl protons towards gamma-deprotonation. (Abstract shortened by UMI.).

  11. Sensitivity of photoelectron diffraction to conformational changes of adsorbed molecules: Tetra-tert-butyl-azobenzene/Au(111

    Directory of Open Access Journals (Sweden)

    A. Schuler

    2017-01-01

    Full Text Available Electron diffraction is a standard tool to investigate the atomic structure of surfaces, interfaces, and adsorbate systems. In particular, photoelectron diffraction is a promising candidate for real-time studies of structural dynamics combining the ultimate time resolution of optical pulses and the high scattering cross-sections for electrons. In view of future time-resolved experiments from molecular layers, we studied the sensitivity of photoelectron diffraction to conformational changes of only a small fraction of molecules in a monolayer adsorbed on a metallic substrate. 3,3′,5,5′-tetra-tert-butyl-azobenzene served as test case. This molecule can be switched between two isomers, trans and cis, by absorption of ultraviolet light. X-ray photoelectron diffraction patterns were recorded from tetra-tert-butyl-azobenzene/Au(111 in thermal equilibrium at room temperature and compared to patterns taken in the photostationary state obtained by exposing the surface to radiation from a high-intensity helium discharge lamp. Difference patterns were simulated by means of multiple-scattering calculations, which allowed us to determine the fraction of molecules that underwent isomerization.

  12. Synthesis of tert-butyl (substituted benzamido)phenylcarbamate derivatives: anti-inflammatory activity and docking studies.

    Science.gov (United States)

    Bhookya, Shankar; Pochampally, Jalapathi; Valeru, Anil; Sunitha, Vianala; Balabadra, Saikrishna; Manga, Vijjulatha; Kudle, Karunakar Rao

    2017-07-01

    A series of new tert-butyl 2-(substituted benzamido) phenylcarbamate (4a-4j) were synthesized by the condensation of tert-butyl 2-amino phenylcarbamate (3) with various substituted carboxylic acid in the presence of EDCI and HOBt as coupling reagent, obtain in excellent yields. The structures of all newly synthesized compounds were characterized spectroscopically and evaluated for in vivo anti-inflammatory activity compared to the standard drug, indomethacin, by using the carrageenan-induced rat paw edema protocol. Most of the compounds exhibited a promising anti-inflammatory activity within 9 to 12 h, the percentage of inhibition values ranging from 54.239 to 39.021%. The results revealed that the compounds 4i and 4a exhibited better or equivalent anti-inflammatory activity with the percentage of inhibition of 54.239 and 54.130%, respectively, which was comparable to standard drug. In addition to experimental results, in silico docking studies was used as a tool to verify and expand the experimental outcomes.

  13. Structure and Vibrational Spectra of Tert-butyl N-(2- bromocyclohex-2-enyl)-N-(2-furylmethyl)carbamate%Tert-butyl(N-(2-bromocyclohex-2-enyl)-N-(2-furylmethyl)carbamate的结构和振动光谱

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The molecular structure, conformational stability, and vibrational frequencies of tert-butyl N-(2-bromocyclohex-2-enyl)-N-(2-furylmethyl)carbamate (TBBFC) were investigated by utilizing the Hartree-Fock (HF) and density functional theory (DFT) ab initio calculations with 6-31G* and 6-31G* * basis sets. The optimized bond length and angle values obtained by HF method showed the best agreement with the experimental values. Comparison of the observed and calculated fundamental vibrational frequencies indicated that B3LYP was superior to the scaled HF approach for molecular problems. Optimal uniform scaling factors calculated for the title compound are 0.899/0.904,0.958/0.961, and 0.988/0.989 for HF, B3LYP, and BLYP (6-31G */6-31G* *), respectively.

  14. Isomerization of 4-Amino-6-tert-butyl-3-methylthio-1, 2,4-triazin-5 (4H)-one with Base

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Isomerizaton of 4-amino-6-tert-butyl-3-methylthio-1, 2, 4-triazin-5 (4H)-one in the presence of base is described. Mechanism of this rearrangement reaction involving four-member ring intermediate formation has been proposed.

  15. Intra-arterial tert-Butyl-hydroperoxide infusion induces an exacerbated sensory response in the rat hind limb and is associated with an impaired tissue oxygen uptake.

    NARCIS (Netherlands)

    Tan, E.C.T.H.; Goor, H. van; Bahrami, S.; Kozlov, A.V.; Leixnering, M.; Redl, H.; Goris, R.J.A.

    2011-01-01

    The objective of this study was to investigate oxidative stress and oxygen extraction mechanisms in an animal model of continuous intra-arterial infusion of a free radical donor and in an in vitro model using isolated mitochondria. tert-Butyl-hydroperoxide (tert-BuOOH, 25 mM) was infused for 24 h in

  16. X-Ray Structure of 8-Quinolinolato Lanthanide Complex:(8-Quinolinolato) bis (2,6-di-tert-butyl-4-methylphenoxo) samarium

    Institute of Scientific and Technical Information of China (English)

    YUAN,Fu-Gen(袁福根); LIU,Qing-Sheng(刘青生); WENG,Lin-Hong(翁林红)

    2002-01-01

    The heteroleptic (8-quinolinolato)bis(2,6-di-tert-butyl-4-methylphenoxo) samarium complex was synthesized and characterized by elemental analysis, IR spectrun and X-ray diffraction analysis. The complex is a five-coordinate dimer. Each 8-quinolinolato oxygen atom links two samarium atoms as a bridge and the Sm-N bond is a typical donor bond.

  17. (1S,3S,4S-tert-Butyl N-[1-benzyl-3-hydroxy-5-phenyl-4-(picolinamidopentyl]carbamate

    Directory of Open Access Journals (Sweden)

    Jian-Feng Zheng

    2008-07-01

    Full Text Available The title compound, C29H35N3O4, was obtained by the reaction of (2S,4S,5S-tert-butyl N-(4-amino-1-benzyl-3-hydroxy-5-phenylpentylcarbamate and picolinic acid using oxalyl chloride as a chlorinating reagent to activate the carboxyl group. In the crystal structure there are two molecules in the asymmetric unit, which are aligned edge-to-face. In one molecule, the pyridyl ring forms a dihedral angle of 22.0 (1° with the phenyl ring of the terminal benzyl group and 14.3 (1° with the other phenyl ring; in the other molecule, the corresponding angles are 12.1 (1 and 10.6 (1°, respectively. The packing is stabilized by intermolecular hydrogen bonds and C—H...π interactions.

  18. Low Temperature Effects on Electrical and Optical Properties of Vacuum Annealed Zinc Tetra- Tert- Butyl 2, 3 Naphthalocyanine Thinfilms

    Directory of Open Access Journals (Sweden)

    C.S. Menon

    2011-01-01

    Full Text Available Electrical and optical properties of thermally evaporated vacuum annealed Zinc 2, 11, 20, 29 Tetra -Tert -Butyl 2, 3 Naphthalocyanine (ZTTBNc thin films are studied. From the Arrhenius plot, the thermal activation energy is calculated for intrinsic and extrinsic region. Different hopping conduction parameters are tabulated using the Variable Range Hopping (VRH model in the low temperature region. Optical absorption spectra of ZTTBNc thinfilm reveals that B bands posses the same wavelength region while Q bands shift to 165 nm from as deposited to maximum vacuum annealed sample. Further the Q band splitting is also absent for 523 K vacuum annealed thinfilm. Also ZNTTBNc thinfilms have a wide optical bandgap with a consistant trap level energy as that of any other organic semiconductors.

  19. Structure-Dependent 4-Tert-Butyl Pyridine-Induced Band Bending at TiO2 Surfaces

    Directory of Open Access Journals (Sweden)

    Mats Göthelid

    2011-01-01

    Full Text Available The role of 4-tert butyl pyridine (4TBP adsorption on TiO2 surface band bending has been studied using photoelectron spectroscopy. Surface oxygen vacancies pin the Fermi level near the conduction band edge on rutile (110. 4TBP preferentially adsorbs in those vacancies and shift the Fermi level to lower binding energy in the band gap. This is done by transferring vacancy excess charge into the empty π∗ orbital in the pyridine ring. The anatase (100 surface contains much less oxygen vacancies although the surface is much rougher than the rutile (110. 4TBP adsorption does not have any significant effect on the surface band bending. Thus the positive role associated with 4TBP addition to solar cell electrolytes is suggested to protection against adsorption of other electrolyte components such as Li and I.

  20. (2E-4-tert-Butyl-2-(4-methoxybenzylidene-3,4-dihydronaphthalen-1(2H-one

    Directory of Open Access Journals (Sweden)

    Mohamed Akhazzane

    2011-07-01

    Full Text Available In the title compound C22H24O2, the exocyclic C=C double bond is in an E configuration and the tert-butyl group is in an axial position on the cyclohexanone ring. The cyclohexanone ring in the dihydronaphthalene fused-ring system adopts a half-chair conformation in both independent two molecules in the asymetric unit. The benzene ring system is oriented angles of 43.97 (12 and 39.24 (12° with respect to the naphthyl ring system in the two independent molecules. In the crystal, molecules are linked via C—H...O hydrogen bonds and C—H...π interactions.

  1. Second harmonic generation at the interface of copper tetra-tert-butyl phthalocyanine Langmuir-Blodgett film/metal

    Institute of Scientific and Technical Information of China (English)

    程晓曼; 姚素薇; 李成全; 间中孝彰; 岩本光正

    2003-01-01

    Optical second harmonic generation (SHG) from the copper tetra-tert-butyl phthalocyanine (CuttbPc) Langmuir-Blodgett (LB) film deposited on a metal-coated glass slide substrate has been investigated. It is considered that the symmetry of the CuttbPc molecule may be broken by the space charge-induced electric field (SCIEF) due to the exchanged charges at the CuttbPc LB film/metal interface. A four-layer model is used to explain the nonlinear optical process in the CuttbPc LB film. The thickness dependence, polarized and incident angle dependence of SHG signal from CuttbPc LB films are calculated. The results of calculation show a good agreement with the experimental data. It is shown that electrostatic phenomena at the interface is correlated closely with SHG signal, and the SHG measurement is also a helpful tool for the detection of the space charge field at the interface.

  2. Immunochemical visualization and identification of rat liver proteins adducted by 2,6-di-tert-butyl-4-methylphenol (BHT).

    Science.gov (United States)

    Reed, M; Thompson, D C

    1997-10-01

    Several alkylphenols (e.g., 2,6-di-tert-butyl-4-methylphenol, BHT) form reactive quinone methide intermediates (e.g., 2,6-di-tert-butyl-4-methylene-2,5-cyclohexadienone, BHT-QM) upon oxidation by cellular enzymes. In order to pursue the role of protein alkylation in alkylphenol toxicity, we used an immunochemical approach to identify protein targets alkylated by BHT. Synthetic BHT-N-acetylcysteine (BHT-NAC) was coupled to keyhole limpet hemocyanin and used as an antigen from which polyclonal antibodies were raised in New Zealand white rabbits. Rabbit serum contained an antibody which was highly specific for BHT-NAC, as determined by competitive ELISA. The BHT antibody was used as a probe to look for the presence of BHT-protein adducts in in vitro incubations with rat liver microsomes or tissue slices and also in vivo in liver tissue from male Sprague-Dawley rats exposed to BHT. Western blotting of protein gels revealed BHT-dependent protein alkylation over a wide molecular weight range. Prominent recurrent bands were observed at approximately 34.5, 52, 64.5, 74, and 97 kDa. Detection of adducts was inhibited in microsomal incubations by cytochrome P450 inhibitors, deuterated BHT, and the omission of NADPH. Similar protein alkylation patterns were observed in rat liver microsomes exposed to synthetically prepared BHT-QM as in the enzyme-mediated incubations. In rats gavaged with up to 1000 mg/kg BHT, the amount of protein alkylation observed was maximal at 24 h postdosing and was dose-dependent. Two alkylated proteins were isolated and identified by N-terminal sequencing: a mitochondrial beta-oxidation enzyme, enoyl-CoA hydratase, and a plasma membrane/cytoskeletal linker protein from the ezrin/moesin/radixin family.

  3. Anti-inflammatory activity of the artificial antioxidants 2-tert-butyl-4-methoxyphenol (BHA), 2,6-di-tert-butyl-4-methylphenol (BHT) and 2,4,6-tri-tert-butylphenol (TBP), and their various combinations.

    Science.gov (United States)

    Murakami, Yukio; Kawata, Akifumi; Katayama, Tadashi; Fujisawa, Seiichiro

    2015-01-01

    The artificial complex phenols, 2-tert-butyl-4-methoxyphenol (BHA), 2,6-di-tert-butyl-4-methylphenol (BHT) and 2,4,6-tri-tert-butylphenol (TBP) exert efficient antioxidant activity; however, they are considerable toxic and potentially tumor-promoting. These phenols, particularly in combinations, have enhanced antioxidant activity due to synergistic interactions and produce bioactive intermediates such as quinone methide. We investigated the anti-inflammatory activity of BHA, BHT and TBP, and combinations of BHT/BHA (in molar ratios of 1:1, 1:2, 1:3 and 2:1), BHT/TBP (1:1), and BHA/TBP (1:1), using gene-expression systems for cyclooxygenase-2 (Cox2) and tumor necrosis facto-alpha (Tnfa) in RAW264.7 cells. The inhibitory effects of BHA, BHT and TBP on expression of Cox2 and Tnfa genes upon stimulation with Escherichia coli lipopolysaccharide (LPS) or Porphyomonas gingivalis (Pg) fimbriae were determined using real-time polymerase chain reaction. The inhibitory effect on expression of Cox2 and Tnfa genes upon stimulation with LPS and fimbriae was greatly enhanced by the combination of two antioxidants (molar ratio 1:1), BHT/BHA. In addition, that of the Cox2 gene, but not of Tnfa gene was slightly enhanced by a combination of equimolar BHT/TBP and BHA/TBP. None of the antioxidants alone exerted any anti-inflammatory activity upon stimulation with LPS, but a slight anti-inflammatory activity was observed upon stimulation with Pg fimbriae. The inhibitory effect of the BHT/BHA combination on expression of Cox2 mRNA upon stimulation with LPS was investigated at afferent molar ratios, and a molar ratio of 1:1 was found to have considerably less effect than a molar ratio of 1:2 or 2:1. The 1:3 combination had no effect. The combination of BHT and BHA at a molar ratio of 0.5-2 exerts potent anti-inflammatory activity. This anti-inflammatory activity on the generation of inflammatory mediators in LPS-activated RAW264.7 cells may be attributable to complex synergistic

  4. tert-Butyl 3-[N-(tert-butoxycarbonylmethylamino]-4-methoxyimino-3-methylpiperidine-1-carboxylate

    Directory of Open Access Journals (Sweden)

    Huiyuan Guo

    2009-02-01

    Full Text Available The title compound, C18H33N3O5, was prepared from N-tert-butoxycarbonyl-4-piperidone using a nine-step reaction, including condensation, methylation, oximation, hydrolysis, esterification, ammonolysis, Hoffmann degradation, tert-butoxycarbonyl protection and methylation. The E configuration of the methyloxime geometry of the compound is confirmed.

  5. Study of an aquifer contaminated by ethyl tert-butyl ether (ETBE): Site characterization and on-site bioremediation

    Energy Technology Data Exchange (ETDEWEB)

    Fayolle-Guichard, Francoise, E-mail: francoise.fayolle@ifpen.fr [IFP Energies nouvelles, 1 et 4 avenue de Bois-Preau, 92852 Rueil-Malmaison (France); Durand, Jonathan [Institut EGID Bordeaux 3, 1 Allee Daguin 33607 Pessac Cedex (France); SERPOL, 2 chemin du Genie, BP 80, 69633 Venissieux Cedex (France); Cheucle, Mathilde [SERPOL, 2 chemin du Genie, BP 80, 69633 Venissieux Cedex (France); Rosell, Monica [Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research - UFZ, Permoserstrasse 15, 04318 Leipzig (Germany); Michelland, Rory Julien [Universite de Lyon, F-69622 Lyon (France); Universite Lyon 1, Villeurbanne (France); CNRS, UMR5557, Ecologie Microbienne (France); Tracol, Jean-Philippe [SERPOL, 2 chemin du Genie, BP 80, 69633 Venissieux Cedex (France); Le Roux, Francoise [IFP Energies nouvelles, 1 et 4 avenue de Bois-Preau, 92852 Rueil-Malmaison (France); Grundman, Genevieve [Universite de Lyon, F-69622 Lyon (France); Universite Lyon 1, Villeurbanne (France); CNRS, UMR5557, Ecologie Microbienne (France); Atteia, Olivier [Institut EGID Bordeaux 3, 1 Allee Daguin 33607 Pessac Cedex (France); Richnow, Hans H. [Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research - UFZ, Permoserstrasse 15, 04318 Leipzig (Germany); Dumestre, Alain [SERPOL, 2 chemin du Genie, BP 80, 69633 Venissieux Cedex (France); and others

    2012-01-30

    Highlights: Black-Right-Pointing-Pointer Ethyl tert-butyl ether (ETBE) (>300 mg L{sup -1}) found in a groundwater (gas-station). Black-Right-Pointing-Pointer No significant carbon or hydrogen isotopic fractionation of ETBE along the plume. Black-Right-Pointing-Pointer MC-IFP culture degraded ETBE (0.91 mg L{sup -1} h{sup -1}) and BTEX (0.64 mg L{sup -1} h{sup -1}). Black-Right-Pointing-Pointer A pilot plant (2 m{sup 3}) inoculated with MC-IFP degraded ETBE in groundwater (15 Degree-Sign C). Black-Right-Pointing-Pointer ethB gene (ETBE biodegradation) amplified during bioaugmentation (5 Multiplication-Sign 10{sup 6}ethB gene copies L{sup -1}). - Abstract: Ethyl tert-butyl ether (ETBE) was detected at high concentration (300 mg L{sup -1}) in the groundwater below a gas-station. No significant carbon neither hydrogen isotopic fractionation of ETBE was detected along the plume. ETBE and BTEX biodegradation capacities of the indigenous microflora Pz1-ETBE and of a culture (MC-IFP) composed of Rhodococcus wratislaviensis IFP 2016, Rhodococcus aetherivorans IFP 2017 and Aquincola tertiaricarbonis IFP 2003 showed that ETBE and BTEX degradation rates were in the same range (ETBE: 0.91 and 0.83 mg L{sup -1} h{sup -1} and BTEX: 0.64 and 0.82 mg L{sup -1} h{sup -1}, respectively) but tert-butanol (TBA) accumulated transiently at a high level using Pz1-ETBE (74 mg L{sup -1}). An on-site pilot plant (2 m{sup 3}) filled with polluted groundwater and inoculated by MC-IFP, successfully degraded four successive additions of ETBE and gasoline. However, an insignificant ETBE isotopic fractionation was also accompanying this decrease which suggested the involvement of low fractionating-strains using EthB enzymes, but required of additional proofs. The ethB gene encoding a cytochrome P450 involved in ETBE biodegradation (present in R. aetherivorans IFP 2017) was monitored by quantitative real-time polymerase chain reaction (q-PCR) on DNA extracted from water sampled in the pilot plant

  6. Solid-Liquid Equilibria of Musk Ketone, Musk Xylene and 1,3-Dimethyl-2,4-Dinitro-5-Tert-Butyl Benzene

    Institute of Scientific and Technical Information of China (English)

    曲红梅; 白鹏; 杨志才; 余国琮

    2004-01-01

    The solid-liquid equilibria of musk ketone + musk xylene, musk xylene+1,3-dimethyl-2,4-dinitro-5-tert-butyl benzene are measured by differential scanning calorimeter (DSC), these systems are proved to be simple eutectics. Moreover the melting points and the fusion enthalpies of musk ketone, musk xylene and 1,3-dimethyl-2,4-dinitro-5-tert-butyl benzene are also measured by the DSC. These solid-liquid equilibrium data and the heats of fusion are reported for the first time. Then UNIFAC model is used to correlate the solid-liquid equilibrium data.It is shown that the solid-liquid equilibria of musk systems can be predicted bv the UNIFAC model.

  7. 2-(4-Bromobenzyl-5,11,17,23-tetra-tert-butyl-25,26,27,28-tetramethoxycalix[4]arene

    Directory of Open Access Journals (Sweden)

    Conrad Fischer

    2009-07-01

    Full Text Available In the title compound, C55H69BrO4, the calixarene molecule displays a `partial cone' conformation bearing the lateral substituent in a sterically favorable equatorial arrangement between two syn-orientated arene units. The crystal packing is stabilized by weak C—H...π contacts, involving one tert-butyl group, and π–stacking interactions of the lateral bromobenzene units [centroid–centroid distance = 3.706 (1 Å].

  8. Vibrio fischeri and Escherichia coli adhesion tendencies towards photolithographically modified nanosmooth poly (tert-butyl methacrylate polymer surfaces

    Directory of Open Access Journals (Sweden)

    Elena P Ivanova

    2008-09-01

    Full Text Available Elena P Ivanova1, Natasa Mitik-Dineva1, Radu C Mocanasu1, Sarah Murphy1, James Wang2, Grant van Riessen3, Russell J Crawford11Faculty Life and Social Sciences; 2IRIS, Swinburne University of Technology, Hawthorn, Victoria, Australia; 3Centre for Materials and Surface Science, La Trobe University, Melbourne, Victoria, AustraliaAbstract: This study reports the adhesion behavior of two bacterial species, Vibrio fischeri and Escherichia coli, to the photoresistant poly(tert-butyl methacrylate (P(tBMA polymer surface. The data has demonstrated that ultraviolet irradiation of P(tBMA was able to provide control over bacterial adhesion tendencies. Following photolithography, several of the surface characteristics of P(tBMA were found to be altered. Atomic force microscopy analysis indicated that photolithographically modified P(tBMA (henceforth termed ‘modified polymer’ appeared as a ‘nanosmooth’ surface with an average surface roughness of 1.6 nm. Although confocal laser scanning microscopy and scanning electron microscopy analysis clearly demonstrated that V. fischeri and E. coli presented largely different patterns of attachment in order to adhere to the same surfaces, both species exhibited a greater adhesion propensity towards the ‘nanosmooth’ surface. The adhesion of both species to the modified polymer surface appeared to be facilitated by an elevated production of extracellular polymeric substances when in contact with the substrate.Keywords: poly(tert-butylmethacrylate polymeric surfaces, surface nanotopography, bacterial attachment, extracellular polymeric substances

  9. Selenium methylselenocysteine protects human hepatoma HepG2 cells against oxidative stress induced by tert-butyl hydroperoxide.

    Science.gov (United States)

    Cuello, Susana; Ramos, Sonia; Mateos, Raquel; Martín, M Angeles; Madrid, Yolanda; Cámara, Carmen; Bravo, Laura; Goya, Luis

    2007-12-01

    Selenium methylselenocysteine (Se-MeSeCys) is a common selenocompound in the diet with a tested chemopreventive effect. This study investigated the potential protective effect of Se-MeSeCys against a chemical oxidative stress induced by tert-butyl hydroperoxide (t-BOOH) on human hepatoma HepG2 cells. Speciation of selenium derivatives by liquid chromatography-inductively coupled plasma mass spectrometry depicts Se-MeSeCys as the only selenocompound in the cell culture. Cell viability (lactate dehydrogenase) and markers of oxidative status--concentration of reduced glutathione (GSH) and malondialdehyde (MDA), generation of reactive oxygen species (ROS) and activity of the antioxidant enzymes glutathione peroxidase (GPx) and glutathione reductase (GR)--were evaluated. Pretreatment of cells with Se-MeSeCys for 20 h completely prevented the enhanced cell damage, MDA concentration and GR and GPx activity and the decreased GSH induced by t-BOOH but did not prevent increased ROS generation. The results show that treatment of HepG2 cells with concentrations of Se-MeSeCys in the nanomolar to micromolar range confers a significant protection against an oxidative insult.

  10. Molecular dynamics and partitioning of di-tert-butyl nitroxide in stratum corneum membranes: effect of terpenes.

    Science.gov (United States)

    Camargos, Heverton Silva; Silva, Adolfo Henrique Moraes; Anjos, Jorge Luiz Vieira; Alonso, Antonio

    2010-05-01

    In this work, we have used electron paramagnetic resonance (EPR) spectroscopy of the small spin label di-tert-butyl nitroxide (DTBN), which partitions the aqueous and hydrocarbon phases, to study the interaction of the terpenes alpha-terpineol, 1,8-cineole, L(-)-carvone and (+)-limonene with the uppermost skin layer, the stratum corneum, and the membrane models of 1,2-dipalmitoyl-sn-glycero-3-phosphatidylcholine (DPPC) and 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC). The EPR spectra indicated that the terpenes increase both the partition coefficient and the rotational correlation time of the spin labels in the stratum corneum membranes, whereas similar effects were observed in the DMPC and DPPC bilayers only at temperatures below the liquid-crystalline phase. The EPR parameter associated to probe polarity inside the membranes showed thermotropically induced changes, suggesting relocations of spin probe, which were dependent on the membrane phases. While the DMPC and DPPC bilayers showed abrupt changes in the partitioning and rotational correlation time parameters in the phase transitions, the SC membranes were characterized by slight changes in the total range of measured temperatures, presenting the greatest changes or membranes reorganizations in the temperature range of approximately 50 to approximately 74 degrees C. The results suggest that terpenes act as spacers, weakening the hydrogen-bonded network at the polar interface and thus fluidizing the stratum corneum lipids.

  11. Study of an aquifer contaminated by ethyl tert-butyl ether (ETBE): site characterization and on-site bioremediation.

    Science.gov (United States)

    Fayolle-Guichard, Françoise; Durand, Jonathan; Cheucle, Mathilde; Rosell, Mònica; Michelland, Rory Julien; Tracol, Jean-Philippe; Le Roux, Françoise; Grundman, Geneviève; Atteia, Olivier; Richnow, Hans H; Dumestre, Alain; Benoit, Yves

    2012-01-30

    Ethyl tert-butyl ether (ETBE) was detected at high concentration (300mgL(-1)) in the groundwater below a gas-station. No significant carbon neither hydrogen isotopic fractionation of ETBE was detected along the plume. ETBE and BTEX biodegradation capacities of the indigenous microflora Pz1-ETBE and of a culture (MC-IFP) composed of Rhodococcus wratislaviensis IFP 2016, Rhodococcus aetherivorans IFP 2017 and Aquincola tertiaricarbonis IFP 2003 showed that ETBE and BTEX degradation rates were in the same range (ETBE: 0.91 and 0.83 mg L(-1)h(-1) and BTEX: 0.64 and 0.82 mg L(-1)h(-1), respectively) but tert-butanol (TBA) accumulated transiently at a high level using Pz1-ETBE (74 mg L(-1)). An on-site pilot plant (2m(3)) filled with polluted groundwater and inoculated by MC-IFP, successfully degraded four successive additions of ETBE and gasoline. However, an insignificant ETBE isotopic fractionation was also accompanying this decrease which suggested the involvement of low fractionating-strains using EthB enzymes, but required of additional proofs. The ethB gene encoding a cytochrome P450 involved in ETBE biodegradation (present in R. aetherivorans IFP 2017) was monitored by quantitative real-time polymerase chain reaction (q-PCR) on DNA extracted from water sampled in the pilot plant which yield up to 5×10(6) copies of ethB gene per L(-1).

  12. Co3(RL)2(hfac)6 ladder complex of 5-[4-(N-tert-butyl-N-aminoxyl)phenyl]pyrimidine.

    Science.gov (United States)

    Field, Lora M; Morón, M Carmen; Lahti, Paul M; Palacio, Fernando; Paduan-Filho, Armando; Oliveira, Nei F

    2006-03-20

    5-[4-(N-tert-butyl-N-aminoxyl)phenyl]pyridimine (4NITPhPyrim = RL) forms a 1-D ladder polymer complex with Co(hfac)2 of stoichiometry Co3(RL)2(hfac)6, having antiparallel [Co(II)RL]n linear chains (rails) that are cross-linked by Pyrim-Co(hfac)2-Pyrim rungs. The magnetic behavior above 100 K is consistent with contributions from one high-spin Co(II) ion (the cross-link, S = 3/2) plus two Co-ON units with strongly antiferromagnetic (AFM) metal-radical exchange (each S = 1). The chiT data show an AFM downturn as the temperature drops. Assuming weak exchange along chain portions of the polymer due to poor spin polarization across the phenyl-pyrimidine bond in RL, a linear three-spin (S = 1, 3/2, and 1) fit to the T > 18 K data yields an AFM cross-linker (rung) effective exchange of J(CL)/k = (-)5.3 K = (-)3.7 cm(-)(1). Superexchange (sigma-orbital overlap) is a likely mechanism for the effective AFM exchange between CoON and Co spin sites in the three-spin groupings.

  13. In situ generation and detection of methyl radical by voltammetry

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    In persulfate-acetate, dimethyl sulfoxide or tert-butyl alcohol systems, in situ generation and detection of methyl free radical are realized with voltammetry. It includes the following successive processes. The persulfate S2O82- is polarographically reduced via one-electron addition to sulfate radical SO4-., the SO4-. Initiates chain reaction with acetate, dimethyl sulfoxide, or tert-butyl alcohol on the electrode surface to produce a methyl radical, and one-electron reduction of the methyl radical yields its polarographic reduction wave. In comparison with the known techniques such as ultraviolet radiolysis coupling with electron spin resonance, etc., the proposed method is simple, sensitive and selective.

  14. ``Living polymers'' in organic solvents : stress relaxation in bicopper tetracarboxylate/tert-butyl cyclohexane solutions

    Science.gov (United States)

    Terech, P.; Maldivi, P.; Dammer, C.

    1994-10-01

    Viscoelastic solutions of a bicopper tetracarboxylate complex in tert-butylcyclohexane have been studied by dynamic rheology in a wide range of concentrations (0.5-1.5 % volume fraction). The zero shear viscosity, the elastic modulus, the terminal stress relaxation time and the height of the high-frequency dip, in a Cole-Cole representation of the complex elastic modulus, follow scaling laws. The related exponents are discussed in the context of the physics of “living polymers” : a term used to describe worm-like species undergoing scission/recombination reactions competing mainly with the reptation motions of the chains. The current system, made up of molecular threads (17.5 Å diameter) of Cu2(O2C-CH(C2H5)C4H9)4 in the apolar solvent, is representative of a “living polymer” where, instead of mechanisms involving transient star polymeric crosslinks, a reversible scission mechanism prevails. The dynamics in the high-frequency range evolves from a regime where reptation is the dominant relaxation mechanism to a cross-over regime where “breathing” fluctuations and Rouse motions become important. Large modifications of the stress relaxation function occur for more concentrated systems. The binary system is the first example of a “living polymer” in an organic solvent and exhibits elastic moduli (G ≈ ca. 120 Pa à φ = 1 %) which are at least 20 times larger than those found for the aqueous “living polymer” systems. Les solutions viscoélastiques d'un tétracarboxylate binucléaire de cuivre dans le tert-butylcyclohexane sont étudiées par rhéologie en mode dynamique dans une gamme étendue de concentrations (0,5 %-15,5 %). La viscosité à gradient nul, le module élastique, le temps terminal de relaxation et la hauteur du puits à haute fréquence, dans une représentation Cole-Cole du module élastique complexe, suivent des lois d'échelles. Les exposants correspondants sont discutés dans le contexte de la physique des “polymères vivants

  15. 4-[(E-(5-tert-Butyl-2-hydroxyphenyldiazenyl]benzoic acid benzene hemisolvate

    Directory of Open Access Journals (Sweden)

    Edward R. T. Tiekink

    2010-03-01

    Full Text Available The title benzene hemisolvate, C17H18N2O3·0.5C6H6, features an essentially planar (the r.m.s. deviation of the non-H atoms, excluding methyl-C, is 0.071 Å diazo molecule with an E conformation about the N=N bond, and a half-molecule of benzene disposed about a centre of inversion. The dihedral angle formed between the benzene rings of the diazo molecule is 7.69 (12°. In the crystal, centrosymmetrically related dimers associate via the eight-membered carboxylic acid dimer synthon, {...HOC(=O}2, and these are connected into a supramolecular chain along the b axis via C—H...O contacts.

  16. Bis{2-[(E-(5-tert-butyl-2-hydroxyphenyldiazenyl]benzoato}dimethyltin(IV

    Directory of Open Access Journals (Sweden)

    Edward R. T. Tiekink

    2011-10-01

    Full Text Available In the title diorganotin dicarboxylate, [Sn(CH32(C17H17N2O32], the tin(IV atom is six-coordinated by four O atoms derived from asymmetrically coordinating carboxylate ligands, and two methyl-C atoms. The resulting C2O4 donor set defines a skew-trapezoidal bipyramid with the Sn—C bonds disposed over the weaker Sn—O bonds. Within each carboxylate ligand, the hydroxyl-H atom forms bifurcated O—H...(O,N hydrogen bonds with carboxylate-O and azo-N atoms. The dihedral angles between the benzene rings in the two ligands are 10.44 (11 and 34.24 (11°. In the crystal, centrosymmetric dimers are formed through pairs of Sn...O interactions [2.8802 (16 Å], and the dimers are linked into supramolecular layers in the ac plane by C—H...π interactions.

  17. Complexation study of a tert-butyl-calix[4]arene-based 2-hydroxynaphthalene ligand with uranium(VI) in non-aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Bauer, Anne; Schmeide, Katja [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Surface Processes

    2017-06-01

    The actinide uranium, well known from nuclear power cycle, plays also a role in rare earth production as it is an undesired constituent of the respective ores. To facilitate the production of rare earth elements, uranium has to be removed. Due to their modifiable selectivity and solubility calix[n]arenes are interesting compounds for the extraction of actinides and lanthanides. The mechanism of uranium(VI) interaction with a tert-butyl-calix[4]arene-based 2-hydroxynaphthalene ligand (L1) was studied by TRLFS, UV-vis spectroscopy and isothermal calorimetry.

  18. Intramolecular interactions between chalcogen atoms: organoseleniums derived from 1-bromo-4-tert-butyl-2,6-di(formyl)benzene.

    Science.gov (United States)

    Zade, Sanjio S; Panda, Snigdha; Singh, Harkesh B; Sunoj, Raghavan B; Butcher, Ray J

    2005-04-29

    [structure: see text] The synthesis and characterization of a series of low-valent organoselenium compounds derived from 1-bromo-4-tert-butyl-2,6-di(formyl)benzene (22) is described. The synthesis of diselenide 25 was achieved by the lithiation route whereas bis(4-tert-butyl-2,6-di(formyl)phenyl) diselenide (26) was synthesized by treating 22 with disodium diselenide. A series of monoselenides (27, 28, and 29) was obtained by facile nucleophilic substitution of bromine in 22, using the corresponding selenolates as nucleophiles. The halogenation reactions of bis(4-tert-butyl-2,6-di(formyl)phenyl) diselenide (26) did not afford the corresponding selenenyl halides but resulted in the isolation of an unexpected cyclic selenenate ester 34 as a product. The selenide 32 was synthesized by the treatment of dimethoxymethyl diselenide with trilithiated 2-bromo-5-tert-butyl-N,N'-di(phenyl)isophthalamide. The existence of potential Se...O intramolecular nonbonding interactions was examined by IR, (1)H, and (77)Se NMR spectroscopy, X-ray crystallography, and computational studies. The X-ray crystal structures of 26 and 27, having two ortho formyl groups, reveal the absence of any Se...O interactions. However, the Se...O interactions were observed in the selenenate ester 34 where one of the formyl groups has been utilized for the selenenate ring formation. The crystal structures of 26 and 27 exhibited intermolecular short-range C-H...Se interactions (hydrogen bonding). Although there are four heteroatoms in carbamoyl moieties ortho to selenium capable of forming a five-membered ring on intramolecular coordination, no such intramolecular Se...X (X = N, O) interaction was observed in the crystal structure of 32. The density functional theory calculations at the B3LYP/6-31G* level predicted that for all the diformyl systems (47a-c, 48a-c), the anti,anti conformer (when both formyl oxygen atoms point away from the selenium) is more stable. This preference was found to be reversed in

  19. Oxidative dissolution of copper and zinc metal in carbon dioxide with tert-butyl peracetate and a beta-diketone chelating agent.

    Science.gov (United States)

    Visintin, Pamela M; Bessel, Carol A; White, Peter S; Schauer, Cynthia K; DeSimone, Joseph M

    2005-01-24

    A series of beta-diketone ligands, R(1)COCH(2)COR(2) [tmhdH (R(1) = R(2) = C(CH(3))(3)); tfacH (R(1) = CF(3); R(2) = CH(3)); hfacH (R(1) = R(2) = CF(3))], in combination with tert-butyl peracetate (t-BuPA), have been investigated as etchant solutions for dissolution of copper metal into carbon dioxide solvent. Copper removal in CO(2) increases in the order tfacH chemical variables in the etching reaction. These t-BuPA/hfacH etchant solutions may find application in a CO(2)-based chemical mechanical planarization (CMP) process.

  20. Bis({tris[2-(3,5-di-tert-butyl-2-oxido-benzylideneamino)ethyl]amine}cerium(III)) diethyl ether solvate.

    Science.gov (United States)

    Dröse, Peter; Hrib, Cristian G; Edelmann, Frank T

    2010-10-13

    The title compound, 2[Ce(C(51)H(75)N(4)O(3))]·C(4)H(10)O, was obtained in high yield (92%) by reduction of (TRENDSAL)Ce(IV)Cl [TRENDSAL is N,N',N''-tris-(3,5-di-tert-butyl-salicyl-ide-natoamino)-triethyl-amine] with potassium in THF. The bulky tripodal TRENDSAL ligand effectively encapsulates the central Ce(III) cation with a Ce-N(imine) distance of 2.860 (2) Å and an average C-N(amine) distance of 2.619 Å within a distorted monocapped octahedral coordination.

  1. Estimated daily intakes of butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT) and tert-butyl hydroquinone (TBHQ) antioxidants in Korea.

    Science.gov (United States)

    Suh, H-J; Chung, M-S; Cho, Y-H; Kim, J-W; Kim, D-H; Han, K-W; Kim, C-J

    2005-12-01

    The study was conducted to establish the estimated daily intake (EDI) of antioxidants such as butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT) and tert-butyl hydroquinone (TBHQ) in Korea. The EDIs were obtained from two sources. One of the estimations was based on the analytical determination of BHA, BHT and TBHQ in 12 food categories (ten food categories for TBHQ) and on individual dietary intake data obtained from the National Health and Nutrition Survey in 1998 (n=11 525, age > 1 year). The other EDIs of BHA, BHT and TBHQ were based on the maximum permitted levels specified in national food standards in Korea and on individual dietary intake data obtained from the National Health and Nutrition Survey in 1998 (n=11 525, age > 1 year). To establish the EDIs based on the analytical determination and on individual dietary intake data, 133 food samples in 12 food categories were selected from the foods considered to be representative sources of BHA, BHT and TBHQ in the Korean diet. Selected samples were analysed by GC with FID. BHA was not detected in any of the samples analysed. BHT and TBHQ were detected in the samples, but the levels were significantly lower than their maximum limits. The EDIs1 of BHT, and TBHQ for average consumers were 0.0156(-3), and 0.0012(-3) mg kg(-1) body weight bw day(-1) and as a proportion of the ADI were 0.0052 and 0.0002%, respectively. For 95th percentile consumers, the EDIs of BHT and TBHQ were 0.0080 and 0.0006 mg kg(-1) bw day(-1), and as a proportion of the ADI were 2.67 and 0.09%, respectively. EDIs for BHA, BHT and TBHQ based on the maximum permitted levels and on individual dietary intake data were 0.04, 0.04 and 0.04 mg kg(-1) bw day(-1), respectively. The EDIs of BHA, BHT and TBHQ for average consumers ranged from 6.00 to 14.42% of the ADI of each antioxidant. According to these results, the EDIs of BHA, BHT and TBHQ in Korea were significantly lower than ADI of these antioxidants established by the JECFA.

  2. Kinetics and Photodegradation Study of Aqueous Methyl tert-Butyl Ether Using Zinc Oxide: The Effect of Particle Size

    Directory of Open Access Journals (Sweden)

    Zaki S. Seddigi

    2013-01-01

    Full Text Available Zinc oxide of different average particle sizes 25 nm, 59 nm, and 421 nm as applied in the photodegradation of MTBE. This study was carried out in a batch photoreactor having a high pressure mercury lamp. Zinc oxide of particle size of 421 nm was found to be the most effective in degrading MTBE in an aqueous solution. On using this type of ZnO in a solution of 100 ppm MTBE, the concentration of MTBE has decreased to 5.1 ppm after a period of five hours. The kinetics of the photocatalytic degradation of MTBE was found to be a first order reaction.

  3. Preparation and characterization of Pd doped ceria–ZnO nanocomposite catalyst for methyl tert-butyl ether (MTBE) photodegradation

    Energy Technology Data Exchange (ETDEWEB)

    Seddigi, Zaki S. [Chemistry Department, Umm Al-Qura University, Makkah (Saudi Arabia); Bumajdad, Ali [Chemistry Department, Faculty of Science, Kuwait University (Kuwait); Ansari, Shahid P. [Chemistry Department, Umm Al-Qura University, Makkah (Saudi Arabia); Ahmed, Saleh A., E-mail: saleh_63@hotmail.com [Chemistry Department, Umm Al-Qura University, Makkah (Saudi Arabia); Danish, Ekram Y. [Chemistry Department, King Abdulaziz University, Jeddah (Saudi Arabia); Yarkandi, Naeema H. [Chemistry Department, Umm Al-Qura University, Makkah (Saudi Arabia); Ahmed, Shakeel [Center for Refining and Petrochemicals, Research Institute, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia)

    2014-01-15

    Highlights: • Novel Pd supported ceria–ZnO photocatalysts were prepared with different amounts of palladium. • The photocatalytic activity of these catalysts was evaluated for degradation of MTBE in water. • Near complete removal of MTBE was achieved using 1% Pd doped ceria–ZnO catalyst and UV irradiation. • Highest rate constant was obtained in case of 1% Pd doped ceria–ZnO catalyst. • Shape and size of pores are important factors for high photoactivity of catalyst. -- Abstract: A series of binary oxide catalysts (ceria–ZnO) were prepared and doped with different amounts of palladium in the range of 0.5%–1.5%. The prepared catalysts were characterized by SEM, TEM, XRD and XPS, as well as by N{sub 2} sorptiometry study. The XPS results confirmed the structure of the Pd CeO{sub 2−x}-ZnO. The photocatalytic activity of these catalysts was evaluated for degradation of MTBE in water. These photocatalyst efficiently degrade a 100 ppm aqueous solution of MTBE upon UV irradiation for 5 h in the presence of 100 mg of each of these photocatalysts. The removal of 99.6% of the MTBE was achieved with the ceria–ZnO catalyst doped with 1% Pd. In addition to the Pd loading, the N{sub 2} sorptiometry study introduced other factors that might affect the catalytic efficiency is the catalyst average pore sizes. The photoreaction was determined to be a first order reaction.

  4. EXPERIMENTAL MEASUREMENT OF THE RATE OF METHYL TERT-BUTYL ETHER HYDROLYSIS IN SUB- AND SUPERCRITICAL WATER. (R826738)

    Science.gov (United States)

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  5. AN EXPERIMENTAL STUDY OF PHYTOREMEDIATION OF METHYL-TERT-BUTYL-ETHER (MTBE) IN GROUNDWATER. (R825549C062)

    Science.gov (United States)

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  6. AN EXPERIMENTAL STUDY OF PHYTOREMEDIATION OF METHYL-TERT-BUTYL-ETHER (MTBE) IN GROUNDWATER. (R825549C062)

    Science.gov (United States)

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  7. Experimental and theoretical studies on new 7-(3,6-di-tert-butyl-9H-carbazol-9-yl)-10-alkyl-10H-phenothiazine-3-carbaldehydes

    Science.gov (United States)

    Stalindurai, Kesavan; Gokula Krishnan, Kannan; Nagarajan, Erumaipatty Rajagounder; Ramalingan, Chennan

    2017-02-01

    Synthesis of fused heterocyclic aldehydes with carbazole (CZ) structural motif linked at C-7 position on phenothiazines (PTZ), 7-(3,6-di-tert-butyl-9H-carbazol-9-yl)-10-butyl-10H-phenothiazine-3-carbaldehyde (1) and 7-(3,6-di-tert-butyl-9H-carbazol-9-yl)-10-hexyl-10H-phenothiazine-3-carbaldehyde (2) has been accomplished and are characterized through experimental and computational techniques. The optimized structure with their bonding aspects and vibrational frequencies of the same have been examined utilizing DFT-B3LYP technique with a basis set 6-311++G(d,p). In the optimized structures of 1 and 2, the bond lengths and bond angles are in accord with their corresponding reported analogous. The vibrational frequencies resulted from experimental as well as theoretical are in well accord with each other. Further, the results of polarizabilities, first order hyperpolarizabilities and dipole moment of 1 and 2 imply that these could be utilized for the preparation of NLO crystals which might generate second order harmonic waves.

  8. Directed Evolution of Carbonyl Reductase from Rhodosporidium toruloides and Its Application in Stereoselective Synthesis of tert-Butyl (3R,5S)-6-Chloro-3,5-dihydroxyhexanoate.

    Science.gov (United States)

    Liu, Zhi-Qiang; Wu, Lin; Zhang, Xiao-Jian; Xue, Ya-Ping; Zheng, Yu-Guo

    2017-05-10

    tert-Butyl (3R,5S)-6-chloro-3,5-dihydroxyhexanoate ((3R,5S)-CDHH) is a key intermediate of atorvastatin and rosuvastatin synthesis. Carbonyl reductase RtSCR9 from Rhodosporidium toruloides exhibited excellent activity toward tert-butyl (S)-6-chloro-5-hydroxy-3-oxohexanoate ((S)-CHOH). For the activity of RtSCR9 to be improved, random mutagenesis and site-saturation mutagenesis were performed. Three positive mutants were obtained (mut-Gln95Asp, mut-Ile144Lys, and mut-Phe156Gln). These mutants exhibited 1.94-, 3.03-, and 1.61-fold and 1.93-, 3.15-, and 1.97-fold improvement in the specific activity and kcat/Km, respectively. Asymmetric reduction of (S)-CHOH by mut-Ile144Lys coupled with glucose dehydrogenase was conducted. The yield and enantiomeric excess of (3R,5S)-CDHH reached 98 and 99%, respectively, after 8 h bioconversion in a single batch reaction with 1 M (S)-CHOH, and the space-time yield reached 542.83 mmol L(-1) h(-1) g(-1) wet cell weight. This study presents a new carbonyl reductase for efficient synthesis of (3R,5S)-CDHH.

  9. Synthesis and Crystal Structure of 4,6-Di-tert-butyl-2-hydroxy-3-(N-1-phenylethyliminomethyl)phenyl bis(triphenylphosphine)palladium bromide

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    The title compound (C59H60BrNOP2Pd, Mr=1047. 3) was synthesized in good yield from α-methylbenzylamine and 4,6-di-tert-butyl-3-formyl-2-hyd roxyphenyl bis( triphenylphosphine)palladium bromide. The latter was obtained from 3-bromo-4,6 -di -tert-butyl-2-hydroxybenzaldehyde and tetrakis(triphenylphosphine)palladium. It crystallizes in monoclinic space group P21/c with the cell dimensions a= 17.882(4 ), b=11.065(2), c=26.143(5)(A), β=90.55(3)°, V=5173(3)(A)3, Z=4, Dc=1.233g cm-3, F(00 0)=2160, μ=1.233 mm-1. The structure was solved by direct methods and r efined by full matrix least-square method, and the final crystallographic discrepancy fa c tor is 0.0647 for 5467 observed reflections. The crystal structure determination of the title compound shows that the coordination environment around the Pd cen tre is tetragonal with two Pd-P bonds of 2.333(2)(A)and 2.339(2)(A), respectively , a Pd-Br length of 2.536(1) and a Pd-C bond of 2.032(8).

  10. 对叔丁基邻苯二酚混合物组成测定法%Detection Method of Tert-butyl Catechol Mixture Composition

    Institute of Scientific and Technical Information of China (English)

    高山

    2013-01-01

      文章对对叔丁基邻苯二酚混合物组成的测定法进行了充分的论证,并得出 SE-54、20 m 毛细管色谱柱可用于对叔丁基邻苯二酚产品组分分析。较佳操作条件为:载气压力:0.08 MPa;柱温:170℃;汽化室温度:300℃;检测器温度250℃;进样量:0.2μL。%Full demonstration of detection method of Tert-butyl catechol mixture composition was made in the paper. The Capillary Column of SE-54, 20 m can be used in Tert-butyl catechol product component analysis. The better operation conditions were the pressure of the carrier gas was 0.08 MPa, column temperature was 170 ℃, vaporizing chamber temperature was 300 ℃, detector temperature was 250 ℃, injection volume was 0.2 μL.

  11. Protective Effects of Rooibos (Aspalathus linearis and/or Red Palm Oil (Elaeis guineensis Supplementation on tert-Butyl Hydroperoxide-Induced Oxidative Hepatotoxicity in Wistar Rats

    Directory of Open Access Journals (Sweden)

    Olawale R. Ajuwon

    2013-01-01

    Full Text Available The possible protective effects of an aqueous rooibos extract (Aspalathus linearis, red palm oil (RPO (Elaeis guineensis, or their combination on tert-butyl-hydroperoxide-(t-BHP-induced oxidative hepatotoxicity in Wistar rats were investigated. tert-butyl hydroperoxide caused a significant (P<0.05 elevation in conjugated dienes (CD and malondialdehyde (MDA levels, significantly (P<0.05 decreased reduced glutathione (GSH and GSH : GSSG ratio, and induced varying changes in activities of catalase, superoxide dismutase, glutathione peroxidase, and glutathione reductase in the blood and liver. This apparent oxidative injury was associated with histopathological changes in liver architecture and elevated levels of serum alanine aminotransferase (ALT, aspartate aminotransferase (AST, and lactate dehydrogenase (LDH. Supplementation with rooibos, RPO, or their combination significantly (P<0.05 decreased CD and MDA levels in the liver and reduced serum level of ALT, AST, and LDH. Likewise, changes observed in the activities of antioxidant enzymes and impairment in redox status in the erythrocytes and liver were reversed. The observed protective effects when rooibos and RPO were supplemented concomitantly were neither additive nor synergistic. Our results suggested that rooibos and RPO, either supplemented alone or combined, are capable of alleviating t-BHP-induced oxidative hepatotoxicity, and the mechanism of this protection may involve inhibition of lipid peroxidation and modulation of antioxidants enzymes and glutathione status.

  12. Protective Effects of Rooibos (Aspalathus linearis) and/or Red Palm Oil (Elaeis guineensis) Supplementation on tert-Butyl Hydroperoxide-Induced Oxidative Hepatotoxicity in Wistar Rats.

    Science.gov (United States)

    Ajuwon, Olawale R; Katengua-Thamahane, Emma; Van Rooyen, Jacques; Oguntibeju, Oluwafemi O; Marnewick, Jeanine L

    2013-01-01

    The possible protective effects of an aqueous rooibos extract (Aspalathus linearis), red palm oil (RPO) (Elaeis guineensis), or their combination on tert-butyl-hydroperoxide-(t-BHP-)induced oxidative hepatotoxicity in Wistar rats were investigated. tert-butyl hydroperoxide caused a significant (P < 0.05) elevation in conjugated dienes (CD) and malondialdehyde (MDA) levels, significantly (P < 0.05) decreased reduced glutathione (GSH) and GSH : GSSG ratio, and induced varying changes in activities of catalase, superoxide dismutase, glutathione peroxidase, and glutathione reductase in the blood and liver. This apparent oxidative injury was associated with histopathological changes in liver architecture and elevated levels of serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), and lactate dehydrogenase (LDH). Supplementation with rooibos, RPO, or their combination significantly (P < 0.05) decreased CD and MDA levels in the liver and reduced serum level of ALT, AST, and LDH. Likewise, changes observed in the activities of antioxidant enzymes and impairment in redox status in the erythrocytes and liver were reversed. The observed protective effects when rooibos and RPO were supplemented concomitantly were neither additive nor synergistic. Our results suggested that rooibos and RPO, either supplemented alone or combined, are capable of alleviating t-BHP-induced oxidative hepatotoxicity, and the mechanism of this protection may involve inhibition of lipid peroxidation and modulation of antioxidants enzymes and glutathione status.

  13. Synthesis and properties of optically active nanostructured polymers bearing amino acid moieties by direct polycondensation of 4,4'-thiobis(2-tert-butyl-5-methylphenol) with chiral diacids.

    Science.gov (United States)

    Mallakpour, Shadpour; Soltanian, Samaneh

    2012-06-01

    Four derivatives of N-trimellitylimido-L-amino acid (4a-4d) were prepared by the reaction of trimellitic anhydride (1) with the L-amino acids (2a-2d) in acetic acid as diacid monomers and were used with the aim to obtain a new family of amino acid based poly(ester-imide)s (PEI)s. The polymerization was performed by direct polycondensation of chiral diacids (4a-4d) with 4,4'-thiobis(2-tert-butyl-5-methylphenol) (5) in the presence of tosyl chloride (TsCl), pyridine and N,N-dimethyl formamide (DMF). Step-growth polymerization was carried out by varying the time of heating and the molar ratio of TsCl/diacid and the optimum conditions were achieved. The synthesized polymers were characterized by means of specific rotation experiments, FT-IR, 1H-NMR, X-ray diffraction techniques and elemental analysis. The surface morphology of the obtained polymers was studied by field emission scanning electron microscopy. The result showed nanostructure morphology of the resulting polymers. The obtained PEIs were soluble in polar aprotic solvents such as DMF, N,N-dimethyl acetamide, dimethyl sulfoxide, N-methyl-2-pyrrolidone and protic solvents such as sulfuric acid. Thermal stability and the weight-loss behavior of the PEIs were studied by thermal gravimetric analysis (TGA) techniques. TGA showed that the 10% weight loss temperature in a nitrogen atmosphere was more than 402°C, therefore they had useful levels of thermal stability associated with excellent solubility.

  14. Microwave-assisted synthesis of sec/tert-butyl 2-arylbenzimidazoles and their unexpected antiproliferative activity towards ER negative breast cancer cells.

    Science.gov (United States)

    Abdul Rahim, Aisyah Saad; Salhimi, Salizawati Muhamad; Arumugam, Natarajan; Pin, Lim Chung; Yee, Ng Shy; Muttiah, Nithya Niranjini; Keat, Wong Boon; Abd Hamid, Shafida; Osman, Hasnah; Mat, Ishak b

    2013-12-01

    A new series of N-sec/tert-butyl 2-arylbenzimidazole derivatives was synthesised in 85-96% yields within 2-3.5 min by condensing ethyl 3-amino-4-butylamino benzoate with various substituted metabisulfite adducts of benzaldehyde under focused microwave irradiation. The benzimidazole analogues were characterised using (1)H NMR, (13)C NMR, high resolution MS and melting points. Evaluation of antiproliferative activity of the benzimidazole analogues against MCF-7 and MDA-MB-231 revealed several compounds with unexpected selective inhibitions of MDA-MB-231 in micromolar range. All analogues were found inactive towards MCF-7. The most potent inhibition against MDA-MB-231 human breast cancer cell line came from the unsubstituted 2-phenylbenzimidazole 10a.

  15. Tetrachlorido[N2,N2′-(dimethylsilanediylbis(N-tert-butyl-3-methylbenzimidamidato-κ2N2,N2′]hafnium(IV

    Directory of Open Access Journals (Sweden)

    Sheng-Di Bai

    2013-12-01

    Full Text Available The symmetric title molecule, [Hf(C26H40N4SiCl4], lies about a twofold rotation axis. The HfIV and Si atoms lie on the rotation axis with all other atoms being in general positions. The HfIV atom is six-coordinated by two N atoms from the N2,N2′-(dimethylsilanediylbis(N-tert-butyl-3-methylbenzimidamidate ligand and four Cl− ions in a slightly distorted octahedral geometry. The two amidinate moieties are connected through the central Si atom with Si—N bond length of 1.762 (3 Å, generating the characteristic N—C—N—Si—N—C—N skeleton of a silyl-linked ansa-bis(amidine species.

  16. Poly[[[diisothiocyanatocobalt(II]-bis[μ-4-tert-butyl-2,6-bis(1,2,4-triazol-1-ylmethylphenol

    Directory of Open Access Journals (Sweden)

    2009-03-01

    Full Text Available In the title compound, {[Co(NCS2(C16H20N6O2]·2C3H7NO·2H2O}n, each CoII ion located on an inversion center is six-coordinated by four equatorial N atoms from four different 4-tert-butyl-2,6-bis(1,2,4-triazol-1-ylmethylphenol (L ligands, and by two N atoms from two axial thiocyanate anions [Co—N = 2.104 (3–2.144 (3 Å]. The metal centres are connected via the bidentate L ligands into two-dimensional polymeric layers parallel to bc plane. The dimethylformamide and solvent water molecules participate in intermolecular O—H...O and O—H...S hydrogen bonds, which consolidate the crystal packing.

  17. Microwave-assisted synthesis and crystal structure of oxo(diperoxo)(4,4'-di-tert-butyl-2,2'-bipyridine)-molybdenum(VI).

    Science.gov (United States)

    Amarante, Tatiana R; Almeida Paz, Filipe A; Gago, Sandra; Gonçalves, Isabel S; Pillinger, Martyn; Rodrigues, Alírio E; Abrantes, Marta

    2009-09-16

    The oxodiperoxo complex MoO(O2)(2)(tbbpy) (tbbpy = 4,4'-di-tert-butyl-2,2'- bipyridine) was isolated from the reaction of MoO2Cl(2)(tbbpy) in water under microwaveassisted heating at 120 masculineC for 4 h. The structure of the oxodiperoxo complex was determined by single crystal X-ray diffraction. The Mo(VI) centre is seven-coordinated with a geometry which strongly resembles a highly distorted bipyramid. Individual MoO(O2)(2)(tbbpy) complexes are interdigitated along the [010] direction to form a column. The crystal structure is formed by the close packing of the columnar-stacked complexes. Interactions between neighbouring columns are essentially of van der Waals type mediated by the need to effectively fill the available space.

  18. Microwave-Assisted Synthesis and Crystal Structure of Oxo(diperoxo(4,4'-di-tert-butyl-2,2'-bipyridine-molybdenum(VI

    Directory of Open Access Journals (Sweden)

    Alírio E. Rodrigues

    2009-09-01

    Full Text Available The oxodiperoxo complex MoO(O22(tbbpy (tbbpy = 4,4'-di-tert-butyl-2,2'- bipyridine was isolated from the reaction of MoO2Cl2(tbbpy in water under microwaveassisted heating at 120 ºC for 4 h. The structure of the oxodiperoxo complex was determined by single crystal X-ray diffraction. The MoVI centre is seven-coordinated with a geometry which strongly resembles a highly distorted bipyramid. Individual MoO(O22(tbbpy complexes are interdigitated along the [010] direction to form a column. The crystal structure is formed by the close packing of the columnar-stacked complexes. Interactions between neighbouring columns are essentially of van der Waals type mediated by the need to effectively fill the available space.

  19. Solid phase microextraction procedure for the determination of alkylphenols in water by on-fiber derivatization with N-tert-butyl-dimethylsilyl-N-methyltrifluoroacetamide.

    Science.gov (United States)

    Pan, Yi-Ping; Tsai, Shih-Wei

    2008-08-29

    The solid phase microextraction (SPME) technique with on-fiber derivatization was evaluated for the analysis of alkylphenols (APs), including 4-tert-octylphenol (4-t-OP), technical nonylphenol isomers (t-NPs) and 4-nonylphenol (4-NP), in water. The 85 microm polyacrylate (PA) fiber was used and a two-step sample preparation procedure was established. In the first step, water sample of 2 mL was placed in a 4 mL PTFE-capped glass vial. Headspace extraction of APs in water was then performed under 65 degrees C for 30 min with 800 rpm magnetic stirring and the addition of 5% of sodium chloride. In the second step, the SPME fiber was placed in another 4 mL vial, which contained 100 microL of N-tert-butyl-dimethylsilyl-N-methyltrifluoroacetamide (MTBSTFA) with 1% tert-butyl-dimethylchlorosilane (TBDMCS). Headspace extraction of MTBSTFA and on-fiber derivatization with APs were performed at 45 degrees C for 10 min. Gas chromatography/mass spectrometry (GC/MS) was used for the analysis of derivatives formed on-fiber. The adsorption-time profiles were also examined. The precision, accuracy and method detection limits (MDLs) for the analysis of all the APs were evaluated with spiked water samples, including detergent water, chlorinated tap water, and lake water. The relative standard deviations were all less than 10% and the accuracies were 100+/-15%. With 2 mL of water sample, MDLs were in the range of 1.58-3.85 ng L(-1). Compared with other techniques, the study described here provided a simple, fast and reliable method for the analysis of APs in water.

  20. Influence of Temperature on Thermodynamic Properties of Methyl t-Butyl Ether (MTBE) + Gasoline Additives

    Science.gov (United States)

    Gonzalez-Olmos, R.; Iglesias, M.; Goenaga, J. M.; Resa, J. M.

    2007-08-01

    The densities and sound speeds of binary mixtures of methyl tert-butyl ether (MTBE) + (benzene, toluene, ethylbenzene, isooctane, tert-butyl alcohol) have been measured at temperatures from 288.15 to 323.15 K and at atmospheric pressure over the complete concentration range. The experimental excess volumes and deviations of isentropic compressibility were calculated. The deviation of isentropic compressibility data have been analyzed in terms of different theoretical models; adequate agreement between the experimental and predicted values is obtained. The data from this study improve the data situation related to gasoline additives and help to understand the MTBE volumetric and acoustic behavior for various chemical systems.

  1. Synthesis of 3-(1-Methyl-1H-imidazol-2-ylthio)propanoic Acid and (E)-3-(1-Methyl-1H-imidazol-2-ylthio)acrylic Acid.

    Science.gov (United States)

    Hattan, Christopher M; Shojaie, Jalil; Lau, Serrine S; Anders, M W

    2013-01-01

    The syntheses of 3-(1-methyl-1H-imidazol-2-ylthio)acrylic acid and 3-(1-methyl-1H-imidazol-2-ylthio)propanoic acid, mitochondria-targeted prodrugs of the antioxidant methimazole, are described. The method of Fan et al. (Fan et al., Synthesis2006, 2286) for the reaction of phenols with propiolic acid and propiolate esters was modified to synthesize (E)-3-(1-methyl-1H-imidazol-2-ylthio)acrylic acid. The intermediate tert-butyl (E)-3-(1-methyl-1H-imidazol-2-ylthio)acrylate was prepared by the reaction of tert-butyl propiolate with methimazole; the use of tert-butyl propiolate rather than methyl propiolate gave tert-butyl (E)-3-(1-methyl-1H-imidazol-2-ylthio)acrylate as the predominant isomer. Acid hydrolysis of the intermediate ester afforded the target compound. 3-(1-Methyl-1H-imidazol-2-ylthio)propanoic acid was synthesized from 3-bromopropanoic acid and methimazole under conditions that gave preferential substitution on sulfur and minimized substitution on nitrogen.

  2. Degradation tests of tert-butyl alcohol by willow trees%柳树对叔丁醇的降解试验

    Institute of Scientific and Technical Information of China (English)

    于晓草; Stefan Trapp

    2003-01-01

    Methyl ten-butyl ether (MTBE) is the most commonly used gasoline oxygenate in the North American's fuel industry. Its persistence in groundwater is of significant concern, which provides a major stimulus for the investigation and research on the environmental sites contaminated with MTBE. There is evidence that MTBE has become one of the most common contaminants in urban groundwater. Aerobic biodegradation has been viewed as one of the most effective methods for treating MTBE contamination, in which MTBE is broken down to the intermediate tert-butyl alcohol (TBA) through the activities of the enzymes cytochrome P-450 monooxygenase (CYP 450s), and TBA is further metabolized to the final products CO2 and H2O. Enzymes of the CYP 450s are the typical enzyme of vascular palnts to play a critical role in the plant metabolism and we therefore have good reasons to believe that palnts would be able to metabolize MTBE. Initial studies indicated that more than 24 plants from 15 families were found to be unable to degrade MTBE. Currently there is no data available in the research of phytoremediation of TBA. This paper examined the degradation potential of ten-butyl alcohol (TBA) by willow trees (Salix alba) within a carefully designed bioreactor. Pre-rooted willow trees were kept in an Erlenmeyer flask of 500 mL with 450 mL spiked aqueous solution for 12 days. TBA and other possible intermediates of TBA were measured by GC/FID. Willow tree uptake tests indicated that 15.26% TBA mass in aqueous solution was removed through willow tree activities at 150C over a 12-day period of exposure. No any other possible metabolite of TBA was tracked and trace amounts of TBA mass (< 1%) were found within the willow tree biomass as insoluble residue during the entire period of tests. Excised willow roots and leaves were also used to investigate the potential of willow trees to degrade TBA within glass vessels with 25 mL spiked solution for 3days. Results of metabolism tests with excised

  3. De aanwezigheid van methyl tert-butylether (MTBE) in drinkwater en drinkwaterbronnen

    NARCIS (Netherlands)

    Morgenstern PP; Korte GAL de; Hogendoorn EA; Versteegh JFM; LWD; IEM

    2002-01-01

    In 2001 the National Institute for Public Health and the Environment (RIVM) in the Netherlands conducted a drinking water measurement programme in co-operation with the Netherlands Waterworks Association (VEWIN) for methyl tert-butyl ether (MTBE) in drinking water and the corresponding sources. This

  4. Contact allergy to 2-hydroxy-5-tert-butyl benzylalcohol and 2,6-bis(hydroxymethyl)-4-tert-butylphenol, components of a phenolic resin used in marking pens

    DEFF Research Database (Denmark)

    Hagdrup, H; Egsgaard, H; Carlsen, L

    1994-01-01

    2-hydroxy-5-tert-butyl benzylalcohol and 2,6-bis(hydroxymethyl)-4-tert-butylphenol were identified as contact allergens in a phenolic resin used as a tackifier in the ink of a marking pen, which, after being used directly on the skin, caused an acute contact dermatitis on the hand of a 13-year......-old boy. The patient also reacted to 4-tert-butylphenol-formaldehyde resin (BPF resin) 1% pet. included in the European standard series....

  5. Molecular structure, vibrational, UV, NMR, HOMO-LUMO, MEP, NLO, NBO analysis of 3,5 di tert butyl 4 hydroxy benzoic acid

    Science.gov (United States)

    Mathammal, R.; Sangeetha, K.; Sangeetha, M.; Mekala, R.; Gadheeja, S.

    2016-09-01

    In this study, we report a combined experimental and theoretical study on molecular structure and vibrational spectra of 3,5 di tert butyl 4 hydroxy benzoic acid. The properties of title compound have been evaluated by quantum chemical calculation (DFT) using B3LYP functional and 6-31 + G (d, p) as basis set. IR Spectra has been recorded using Fourier transform infrared spectroscopy (FT-IR) in the region 4000-400 cm-1. The vibrational assignment of the calculated normal modes has been made on the basis set. The isotropic chemical shifts computed by 13C and 1H NMR (Nuclear Magnetic Resonance) analyses also show good agreement with experimental observations. The theoretical UV-Vis spectrum of the compound are used to study the visible absorption maxima (λ max). The structure activity relationship have been interpreted by mapping electrostatic potential surface (MEP), which is valuable information for the quality control of medicines and drug receptor interactions. The Mullikan charges, HOMO (Highest Occupied Molecular Orbital) - LUMO (Lowest Unoccupied Molecular Orbital) energy are analyzed. HOMO-LUMO energy gap and other related molecular properties are also calculated. The Natural Bond Orbital (NBO) analysis is carried out to investigate the various intra and inter molecular interactions of molecular system. The Non-linear optical properties such as dipole moment (μ), polarizability (αtot) and molecular first order hyperpolarizability (β) of the title compound are computed with B3LYP/6-31 + G (d,p) level of theory.

  6. Conformational stability, molecular orbital studies (chemical hardness and potential), vibrational investigation and theoretical NBO analysis of 4-tert-butyl-3-methoxy-2,6-dinitrotoluene.

    Science.gov (United States)

    Saravanan, S; Balachandran, V; Vishwanathan, K

    2014-04-24

    The FT-IR and FT-Raman spectra of 4-tert-butyl-3-methoxy-2,6-dinitrotoluene (musk ambrette) have been recorded in the regions 4000-400 cm(-1) and 3500-100 cm(-1), respectively. The total energy calculations of musk ambrette were tried for the possible conformers. The molecular structure, geometry optimization, vibrational frequencies were obtained by the density functional theory (DFT) using B3LYP and LSDA method with 6-311G(d,p) basis set for the most stable conformer "C1". The complete assignments were performed on the basis of the potential energy distribution (PED) of the vibrational modes, calculated and the scaled values were compared with experimental FT-IR and FT-Raman spectra. The observed and the calculated frequencies are found to be in good agreement. The stability of the molecule arising from hyper conjugate interactions and the charge delocalization has been analyzed using bond orbital (NBO) analysis. The HOMO and LUMO energy gap reveals that the energy gap reflects the chemical activity of the molecule. The dipole moment (μ), polarizability (α), anisotropy polarizability (Δα) and first hyperpolarizability (βtot) of the molecule have been reported. The thermodynamic functions (heat capacity, entropy and enthalpy) were obtained for the range of temperature 100-1000 K. Information about the size, shape, charge density distribution and site of chemical reactivity of the molecule has been obtained by mapping electron density isosurface with molecular electrostatic potential (MEP).

  7. Synthesis and molecular structure of indium complexes based on 3,6-di-tert-butyl-o-benzoquinone. Looking for indium(I) o-semiquinolate.

    Science.gov (United States)

    Piskunov, Alexandr V; Maleeva, Aryna V; Fukin, Georgii K; Baranov, Evgenii V; Bogomyakov, Artem S; Cherkasov, Vladimir K; Abakumov, Gleb A

    2011-01-21

    The interaction of 3,6-di-tert-butyl-o-benzoquinone (3,6-Q) with indium in toluene leads to the tris-o-semiquinolate derivative (3,6-SQ)(3)In (3,6-SQ - radical-anion of 3,6-Q). According to single-crystal X-ray diffraction analysis, this complex has a trigonal prismatic structure. Magnetic measurements revealed that the exchange interactions between odd electrons of the paramagnetic ligands in (3,6-SQ)(3)In are antiferromagnetic in character. The treatment of (3,6-SQ)(3)In with 2,2'-dipyridyl (Dipy) causes the displacement of one o-quinone ligand and the formation of the (3,6-SQ)In(Dipy)(3,6-Cat) (3,6-Cat - dianion of 3,6-Q) derivative containing mixed charged o-quinoid ligands. The reaction of InI with (3,6-SQ)K in THF solution is accompanied by a redox process and the potassium-indium(iii) catecholate derivative was obtained as a result. The oxidation of InI with 3,6-Q in THF produces the dimeric In(iii) iodo-catecholate complex [(3,6-Cat)(2)In·2THF]InI(2). The same derivative can be synthesized by the interaction of indium metal with a mixture of I(2) and 3,6-Q.

  8. Selective liquid phase oxidation of benzyl alcohol to benzaldehyde by tert-butyl hydroperoxide over γ-Al2O3 supported copper and gold nanoparticles

    Science.gov (United States)

    Ndolomingo, Matumuene Joe; Meijboom, Reinout

    2017-03-01

    Benzyl alcohol oxidation to benzaldehyde was performed by tert-butyl hydroperoxide (TBHP) in the absence of any solvent using γ-Al2O3 supported copper and gold nanoparticles. Li2O and ionic liquids were used as additive and stabilizers for the synthesis of the catalysts. The physico-chemical properties of the catalysts were characterized by atomic absorption spectroscopy (AAS), X-ray diffraction spectroscopy (XRD), N2 absorption/desorption (BET), transmission electron microscopy (TEM), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and temperature programmed reduction (TPR), whereas, the oxidation reaction was followed by gas chromatography with a flame ionization detector (GC-FID). The as prepared catalysts exhibited good catalytic performance in terms of conversion and selectivity towards benzaldehyde. The performance of the Au-based catalysts is significantly higher than that of the Cu-based catalysts. For both Cu and Au catalysts, the conversion of benzyl alcohol increased as the reaction proceeds, while the selectivity for benzaldehyde decreased. Moreover, the catalysts can be easily recycled and reused with neither significant loss of activity nor selectivity. A kinetic study for the Cu and Au-catalyzed oxidation of benzyl alcohol to benzyldehyde is reported. The rate at which the oxidation of benzyl alcohol is occurring as a function of catalyst and oxidant amounts was investigated, with the apparent rate constant, kapp being proportional to the amount of nano catalyst and oxygen present in the system.

  9. The Inhibition Effect of Tert-Butyl Alcohol on the TiO2 Nano Assays Photoelectrocatalytic Degradation of Different Organics and Its Mechanism

    Institute of Scientific and Technical Information of China (English)

    Xuejin Li; Jinhua Li; Jing Bai; Yifan Dong; Linsen Li; Baoxue Zhou

    2016-01-01

    The inhibition effect of tert-butyl alcohol (TBA), identified as the •OH radical inhibitor, on the TiO2 nano assays (TNA) photoelectrocatalytic oxidation of different organics such as glucose and phthalate was reported. The adsorption performance of these organics on the TNA photoelectrode was investigated by using the instantaneous pho-tocurrent value, and the degradation property was examined by using the exhausted reaction. The results showed that glucose exhibited the poor adsorption and easy degradation performance, phthalate showed the strong adsorption and hard-degradation, but TBA showed the weak adsorption and was the most difficult to be degraded. The degradation of both glucose and phthalate could be inhibited evidently by TBA. But the effect on glucose was more obvious. The different inhibition effects of TBA on different organics could be attributed to the differences in the adsorption and the degradation property. For instance, phthalate of the strong adsorption property could avoid from the capture of •OH radicals by TBA in TNA photoelectrocatalytic process.

  10. Kilohertz Pulsed-Laser-Polymerization: Simultaneous Determination of Backbiting, Secondary, and Tertiary Radical Propagation Rate Coefficients for tert-Butyl Acrylate.

    Science.gov (United States)

    Wenn, Benjamin; Junkers, Thomas

    2016-05-01

    For the first time, a 1000 Hz pulse laser has been applied to determine detailed kinetic rate coefficients from pulsed laser polymerization-size exclusion chromatography experiments. For the monomer tert-butyl acrylate, apparent propagation rate coefficients kp (app) have been determined in the temperature range of 0-80 °C. kp (app) in the range of few hundreds to close to 50 000 L·mol(-1) ·s(-1) are determined for low and high pulse frequencies, respectively. The apparent propagation coefficients show a distinct pulse-frequency dependency, which follows an S-shape curve. From these curves, rate coefficients for secondary radial propagation (kp (SPR) ), backbiting (kbb ), midchain radical propagation (kp (tert) ), and the (residual) effective propagation rate (kp (eff) ) can be deduced via a herein proposed simple Predici fitting procedure. For kp (SPR) , the activation energy is determined to be (17.9 ± 0.6) kJ·mol(-1) in excellent agreement with literature data. For kbb , an activation energy of (25.9 ± 2.2) kJ·mol(-1) is deduced.

  11. Microbial phenolic metabolites improve glucose-stimulated insulin secretion and protect pancreatic beta cells against tert-butyl hydroperoxide-induced toxicity via ERKs and PKC pathways.

    Science.gov (United States)

    Fernández-Millán, Elisa; Ramos, Sonia; Alvarez, Carmen; Bravo, Laura; Goya, Luis; Martín, María Ángeles

    2014-04-01

    Oxidative stress is accepted as one of the causes of beta cell failure in type 2 diabetes. Therefore, identification of natural antioxidant agents that preserve beta cell mass and function is considered an interesting strategy to prevent or treat diabetes. Recent evidences indicated that colonic metabolites derived from flavonoids could possess beneficial effects on various tissues. The aim of this work was to establish the potential anti-diabetic properties of the microbial-derived flavonoid metabolites 3,4-dihydroxyphenylacetic acid (DHPAA), 2,3-dihydroxybenzoic acid (DHBA) and 3-hydroxyphenylpropionic acid (HPPA). To this end, we tested their ability to influence beta cell function and to protect against tert-butyl hydroperoxide-induced beta cell toxicity. DHPAA and HPPA were able to potentiate glucose-stimulated insulin secretion (GSIS) in a beta cell line INS-1E and in rat pancreatic islets. Moreover, pre-treatment of cells with both compounds protected against beta cell dysfunction and death induced by the pro-oxidant. Finally, experiments with pharmacological inhibitors indicate that these effects were mediated by the activation of protein kinase C and the extracellular regulated kinases pathways. Altogether, these findings strongly suggest that the microbial-derived flavonoid metabolites DHPAA and HPPA may have anti-diabetic potential by promoting survival and function of pancreatic beta cells.

  12. Low-temperature CVD of iron, cobalt, and nickel nitride thin films from bis[di(tert-butyl)amido]metal(II) precursors and ammonia

    Energy Technology Data Exchange (ETDEWEB)

    Cloud, Andrew N.; Abelson, John R., E-mail: abelson@illinois.edu [Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, 201 Materials Science and Engineering Building, 1304 W. Green St., Urbana, Illinois 61801 (United States); Davis, Luke M.; Girolami, Gregory S., E-mail: girolami@scs.illinois.edu [School of Chemical Sciences, University of Illinois at Urbana-Champaign, 600 S. Mathews Ave., Urbana, Illinois 61801 (United States)

    2014-03-15

    Thin films of late transition metal nitrides (where the metal is iron, cobalt, or nickel) are grown by low-pressure metalorganic chemical vapor deposition from bis[di(tert-butyl)amido]metal(II) precursors and ammonia. These metal nitrides are known to have useful mechanical and magnetic properties, but there are few thin film growth techniques to produce them based on a single precursor family. The authors report the deposition of metal nitride thin films below 300 °C from three recently synthesized M[N(t-Bu){sub 2}]{sub 2} precursors, where M = Fe, Co, and Ni, with growth onset as low as room temperature. Metal-rich phases are obtained with constant nitrogen content from growth onset to 200 °C over a range of feedstock partial pressures. Carbon contamination in the films is minimal for iron and cobalt nitride, but similar to the nitrogen concentration for nickel nitride. X-ray photoelectron spectroscopy indicates that the incorporated nitrogen is present as metal nitride, even for films grown at the reaction onset temperature. Deposition rates of up to 18 nm/min are observed. The film morphologies, growth rates, and compositions are consistent with a gas-phase transamination reaction that produces precursor species with high sticking coefficients and low surface mobilities.

  13. Vibrational frequency analysis, FT-IR, DFT and M06-2X studies on tert-Butyl N-(thiophen-2yl)carbamate

    Science.gov (United States)

    Sert, Yusuf; Singer, L. M.; Findlater, M.; Doğan, Hatice; Çırak, Ç.

    2014-07-01

    In this study, the experimental and theoretical vibrational frequencies of a newly synthesized tert-Butyl N-(thiophen-2yl)carbamate have been investigated. The experimental FT-IR (4000-400 cm-1) spectrum of the molecule in the solid phase have been recorded. The theoretical vibrational frequencies and optimized geometric parameters (bond lengths and bond angles) have been calculated by using density functional theory (DFT/B3LYP: Becke, 3-parameter, Lee-Yang-Parr) and DFT/M06-2X (the highly parametrized, empirical exchange correlation function) quantum chemical methods with the 6-311++G(d,p) basis set by Gaussian 09W software, for the first time. The vibrational frequencies have been assigned using potential energy distribution (PED) analysis by using VEDA 4 software. The computational optimized geometric parameters and vibrational frequencies have been found to be in good agreement with the corresponding experimental data, and with related literature results. In addition, the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) energies and the other related molecular energy values have been calculated and are depicted.

  14. Effects of colored and noncolored phenolics of Echium plantagineum L. bee pollen in Caco-2 cells under oxidative stress induced by tert-butyl hydroperoxide.

    Science.gov (United States)

    Sousa, Carla; Moita, Eduarda; Valentão, Patrícia; Fernandes, Fátima; Monteiro, Pedro; Andrade, Paula B

    2015-02-25

    Bee pollen is used as a dietary supplement, being promoted as a health food. Echium plantagineum L. bee pollen fractions enriched in flavonols (fraction I) or anthocyanins (fraction II) and the whole extract were characterized by HPLC-DAD. Both in the whole extract and in fraction II seven flavonols and five anthocyanins were identified, while fraction I contained six flavonols (in higher levels than fraction II) and small amounts of petunidin-3-O-rutinoside. Antioxidant capacity was evaluated in Caco-2 cells under oxidative stress induced by tert-butyl hydroperoxide (t-BHP). Fraction I pre-exposure imparted a tendency to protect cells, while fraction II and the whole extract aggravated t-BHP toxicity at some concentrations. The protective effects seem to be correlated with the levels of total glutathione, while no correlation between cellular viability and reactive species was seen. The extracts displayed no significant effect on antioxidant enzymes activity. Overall, anthocyanins seem to abrogate the antioxidant potential of flavonoid-rich extracts.

  15. Ethyl tert-butyl ether (ETBE) biodegradation by a syntrophic association of Rhodococcus sp. IFP 2042 and Bradyrhizobium sp. IFP 2049 isolated from a polluted aquifer.

    Science.gov (United States)

    Le Digabel, Yoann; Demanèche, Sandrine; Benoit, Yves; Vogel, Timothy M; Fayolle-Guichard, Françoise

    2013-12-01

    Ethyl tert-butyl ether (ETBE) enrichment was obtained by adding contaminated groundwater to a mineral medium containing ETBE as the sole carbon and energy source. ETBE was completely degraded to biomass and CO2 with a transient production of tert-butanol (TBA) and a final biomass yield of 0.37 ± 0.08 mg biomass (dry weight).mg(-1) ETBE. Two bacterial strains, IFP 2042 and IFP 2049, were isolated from the enrichment, and their 16S rRNA genes (rrs) were similar to Rhodococcus sp. (99 % similarity to Rhodococcus erythropolis) and Bradyrhizobium sp. (99 % similarity to Bradyrhizobium japonicum), respectively. Rhodococcus sp. IFP 2042 degraded ETBE to TBA, and Bradyrhizobium sp. IFP 2049 degraded TBA to biomass and CO2. A mixed culture of IFP 2042 and IFP 2049 degraded ETBE to CO2 with a biomass yield similar to the original ETBE enrichment (0.31 ± 0.02 mg biomass.mg(-1) ETBE). Among the genes previously described to be involved in ETBE, MTBE, and TBA degradation, only alkB was detected in Rhodococcus sp. IFP 2042 by PCR, and none were detected in Bradyrhizobium sp. IFP 2049.

  16. Evaluation of ethyl tert-butyl ether biodegradation in a contaminated aquifer by compound-specific isotope analysis and in situ microcosms.

    Science.gov (United States)

    Bombach, Petra; Nägele, Norbert; Rosell, Mònica; Richnow, Hans H; Fischer, Anko

    2015-04-09

    Ethyl tert-butyl ether (ETBE) is an upcoming groundwater pollutant in Europe whose environmental fate has been less investigated, thus far. In the present study, we investigated the in situ biodegradation of ETBE in a fuel-contaminated aquifer using compound-specific stable isotope analysis (CSIA), and in situ microcosms in combination with total lipid fatty acid (TLFA)-stable isotope probing (SIP). In a first field investigation, CSIA revealed insignificant carbon isotope fractionation, but low hydrogen isotope fractionation of up to +14‰ along the prevailing anoxic ETBE plume suggesting biodegradation of ETBE. Ten months later, oxygen injection was conducted to enhance the biodegradation of petroleum hydrocarbons (PH) at the field site. Within the framework of this remediation measure, in situ microcosms loaded with [(13)C6]-ETBE (BACTRAP(®)s) were exposed for 119 days in selected groundwater wells to assess the biodegradation of ETBE by TLFA-SIP under the following conditions: (i) ETBE as main contaminant; (ii) ETBE as main contaminant subjected to oxygen injection; (iii) ETBE plus other PH; (iv) ETBE plus other PH subjected to oxygen injection. Under all conditions investigated, significant (13)C-incorporation into microbial total lipid fatty acids extracted from the in situ microcosms was found, providing clear evidence of ETBE biodegradation.

  17. Cyclic M2(RL)2 coordination complexes of 5-(3-[N-tert-Butyl-N-aminoxyl]phenyl)pyrimidine with paramagnetic transition metal dications.

    Science.gov (United States)

    Baskett, Martha; Lahti, Paul M; Paduan-Filho, Armando; Oliveira, Nei F

    2005-09-19

    5-(3-(N-tert-Butyl-N-aminoxyl)phenyl)pyrimidine (RL = 3NITPhPyrim) forms isostructural cyclic M2(RL)2 cyclic dimers with M(hfac)2 (M = Mn, Co, Cu; hfac = hexafluoroacetylacetonate). Mn2(hfac)4(RL)2 exhibits strong antiferromagnetic Mn-RL exchange, with weak ferromagnetic exchange (0.7 cm(-1)) between Mn-RL units that is consistent with a spin polarization exchange mechanism. The magnetic moment of Co2(hfac)4(RL)2 at higher temperatures is consistent with strongly antiferromagnetic exchange within the Co-NIT units and tends toward zero below 50 K at lower magnetic fields. Cu2(hfac)4(RL)2 shows more complex behavior, with no high-temperature plateau in chiT(T) up to 300 K but a monotonic decrease down to about 100 K. The Cu(II)-nitroxide bonds decrease by 0.2-0.3 A over the same temperature range, corresponding to a change of nitroxide coordination from axial to equatorial. This thermally reversible Jahn-Teller distortion leads to a thermally induced spin state conversion from a high-spin, paramagnetic state at higher temperature to a low-spin state at lower temperature. This spin state conversion is accompanied by a reversible solid-state thermochromic change between dull yellow-brown at room temperature and green at 77 K.

  18. TOXICITY OF METHYL-TERT BYTYL ETHER (MTBE) TO PLANTS (AVENA SATIVA, ZEA MAYS, TRITICUM AESTIVUM, AND LACTUCA SATIVA)

    Science.gov (United States)

    Effects of Methyl tert-butyl ether (MTBE) on the germination of seeds and growth of the plant were studied in some laboratory experiments. Test plants were wild oat (Avena sative), sweet corn (Zea mays), wheat (Triticum aestivum), and lettuce (Lactuca sativa). Seed germination,...

  19. TOXICITY OF METHYL-TERT BYTYL ETHER (MTBE) TO PLANTS (AVENA SATIVA, ZEA MAYS, TRITICUM AESTIVUM, AND LACTUCA SATIVA)

    Science.gov (United States)

    Effects of Methyl tert-butyl ether (MTBE) on the germination of seeds and growth of the plant were studied in some laboratory experiments. Test plants were wild oat (Avena sative), sweet corn (Zea mays), wheat (Triticum aestivum), and lettuce (Lactuca sativa). Seed germination,...

  20. Cleavage of carbon-nitrogen bond in 1,3,5-tri-tert-butyl-1,3,5-triazacyclohexane by copper(I) bromide

    Science.gov (United States)

    Khatua, Suman; Majumdar, Amit

    2016-09-01

    Reactions of CuCl, CuCl2 and CuBr2 with 1,3,5-tri-tert-butyl-1,3,5-triazacyclohexane (tBu3tach) resulted in the formation of [(tBu3tach-H)+(CuCl2)] (1), [(tBu3tach)(CuCl2)] (2) and [(tBu3tach-H)+(CuBr2)] (3) respectively. Interestingly, CuBr was found to mediate the cleavage of the C-N bonds of tBu3tach in a vast range of solvents, namely, chloroform, dichloromethane, tetrahydrofuran, acetonitrile and methanol to yield [Cu4Br4(tBuNCH2)4] (4) and stands as an example of C-N bond cleavage of 1,3,5-triazacyclohexane rings by copper salts. Compounds 1 and 3 contains amidinium cations and are unstable in solution towards the release of copper. The release of copper from 3 in solution was confirmed by the isolation of the compound, [CuBr(MeCN)] (5). Formation of the amidinium cations [(tBu3tach-H)+] in 1 and 3 may be avoided by the use of PPh3 to yield [(tBu3tach)Cu(PPh3)](PF6) (6), while the coordinated N-tert-butylmethanimine (tBuNCH2) in 4 could be replaced by PPh3 to yield [Cu4Br4(PPh3)4] (7). Complexes 1-7 are characterized by a combination of single crystal X-ray structure determination and/or elemental analysis, NMR, IR, and UV-Vis spectroscopy, and Mass spectrometry.

  1. Simultaneous determination of organotin compounds in textiles by gas chromatography-flame photometry following liquid/liquid partitioning with tert-butyl ethyl ether after reflux-extraction.

    Science.gov (United States)

    Hamasaki, Tetsuo

    2013-10-15

    A rapid and relatively clean method for determining six organotin compounds (OtC) in textile goods with a gas chromatograph equipped with a conventional flame photometric detector (GC-FPD) has been developed. After the reflux-extraction to use methanol containing 1% (v/v) of hydrochloric acid, five hydrophobic OtC (e.g. tributyltin: TBT) and slightly less hydrophobic dibutyltin (DBT) could be drawn out through partitioning between the methanolic buffer solution and tert-butyl ethyl ether instead of hazardous dichloromethane, of which usage is provided by the official-methods notified in Japan, and following the ethylation procedure to use sodium tetraethylborate, the OtC were determined with the GC-FPD. The recoveries of DBT, TBT, tetrabutyltin, triphenyltin, dioctyltin, and trioctyltin from textile products (cloth diaper, socks, and undershirt) were 60-77, 89-98, 86-94, 71-78, 85-109, and 70-79% respectively, and their coefficients of variation were 2.5-16.5%. Calibration curves for OtC were linear (0.01-0.20 μg as Sn mL(-1)), and the correlation coefficients were 0.9922-1.0000. Their detection limits were estimated to be 2.7-9.7 n gas Sn g(-1). These data suggested that this method would be applicable to their simultaneous determination. Five retailed textile goods were analyzed by this proposed method, and 0.013-0.65 µg as Sn g(-1) of OtC (e.g. DBT) were determined in three. Moreover, a possibility that various OtC including non-targeted species in textile would be specifically detected by applying the studying speciation-technique of controlling signal intensity-flame fuel gas pressures of the GC-FPD was found.

  2. Evaluation of ethyl tert-butyl ether biodegradation in a contaminated aquifer by compound-specific isotope analysis and in situ microcosms

    Energy Technology Data Exchange (ETDEWEB)

    Bombach, Petra, E-mail: petra.bombach@ufz.de [UFZ – Helmholtz Centre for Environmental Research, Department of Isotope Biogeochemistry, Permoserstrasse 15, D-04318 Leipzig (Germany); Isodetect GmbH Leipzig, Deutscher Platz 5b, D-04103 Leipzig (Germany); Nägele, Norbert [Kuvier the Biotech Company S.L., Ctra. N-I, p.k. 234–P.E. INBISA 23" a, E-09001 Burgos (Spain); Rosell, Mònica [UFZ – Helmholtz Centre for Environmental Research, Department of Isotope Biogeochemistry, Permoserstrasse 15, D-04318 Leipzig (Germany); Grup de Mineralogia Aplicada i Medi Ambient, Departament de Cristallografia, Mineralogia i Dipòsits Minerals, Facultat de Geologia, Universitat de Barcelona (UB), C/Martí i Franquès s/n, 08028 Barcelona (Spain); Richnow, Hans H. [UFZ – Helmholtz Centre for Environmental Research, Department of Isotope Biogeochemistry, Permoserstrasse 15, D-04318 Leipzig (Germany); Fischer, Anko [Isodetect GmbH Leipzig, Deutscher Platz 5b, D-04103 Leipzig (Germany)

    2015-04-09

    Highlights: • In situ biodegradation of ETBE was investigated in a fuel contaminated aquifer. • Degradation was studied by CSIA and in situ microcosms in combination with TLFA-SIP. • ETBE was degraded when ETBE was the main groundwater contaminant. • ETBE was also degraded in the presence of BTEX and MTBE. • Hydrochemical analysis indicated aerobic and anaerobic ETBE biodegradation. - Abstract: Ethyl tert-butyl ether (ETBE) is an upcoming groundwater pollutant in Europe whose environmental fate has been less investigated, thus far. In the present study, we investigated the in situ biodegradation of ETBE in a fuel-contaminated aquifer using compound-specific stable isotope analysis (CSIA), and in situ microcosms in combination with total lipid fatty acid (TLFA)-stable isotope probing (SIP). In a first field investigation, CSIA revealed insignificant carbon isotope fractionation, but low hydrogen isotope fractionation of up to +14‰ along the prevailing anoxic ETBE plume suggesting biodegradation of ETBE. Ten months later, oxygen injection was conducted to enhance the biodegradation of petroleum hydrocarbons (PH) at the field site. Within the framework of this remediation measure, in situ microcosms loaded with [{sup 13}C{sub 6}]-ETBE (BACTRAP{sup ®}s) were exposed for 119 days in selected groundwater wells to assess the biodegradation of ETBE by TLFA-SIP under the following conditions: (i) ETBE as main contaminant; (ii) ETBE as main contaminant subjected to oxygen injection; (iii) ETBE plus other PH; (iv) ETBE plus other PH subjected to oxygen injection. Under all conditions investigated, significant {sup 13}C-incorporation into microbial total lipid fatty acids extracted from the in situ microcosms was found, providing clear evidence of ETBE biodegradation.

  3. Alkylation of catechol with tert-butyl alcohol catalyzed by mesoporous acidic montmorillonite heterostructure catalysts%中孔酸性蒙脱石基复合材料催化邻苯二酚-叔丁醇烷基化反应研究

    Institute of Scientific and Technical Information of China (English)

    周春晖; 葛忠华; 李小年; 童东绅; 李庆伟; 郭红强

    2004-01-01

    The liquid phase alkylation of catechol with tert-butyl alcohol to produce 4-tert-butyl catechol(4-TBC)was carried out over MCM-41,HZSM-5,H-exchanged montmorillonite and novel acidic porous montmorillonite heterostructures(PMHs).Upon all catalysts tested,4-TBC is the main product and 3-tert-butyl catechol(3-TBC)and 3,5-di-tert-butyl catechol are the side products.The synthetic PMHs showed higher conversion of catechol and better selectivity to 4-TBC compared to other solid acid catalysts tested.Over the PMHs derived from H-exchanged montmorillonite through template extraction processes,the suitable reaction temperature is ca 410 K,the ratio of catechol to tert-butyl alcohol is 1:2.Increasing the amount of catalyst(lower weight hourly space velocity)can improve the conversion of catechol and influence the selectivity slightly.The reasonable reaction time is ca 8 h.The type and strength of acidity of H-montmorillonite and PMH were determined by pyridine adsorption FT-IR and ammonia temperature-programmed desorption techniques.The medium and strong acid sites are conducive to producing 4-TBC and the weak acid sites to facilitating the 3-TBC formation.The differences between the PMHs from calcination and those from extraction are attributed to proton migration and acidity change in the gallery surface.

  4. Ground-State Distortion in N-Acyl-tert-butyl-carbamates (Boc) and N-Acyl-tosylamides (Ts): Twisted Amides of Relevance to Amide N-C Cross-Coupling.

    Science.gov (United States)

    Szostak, Roman; Shi, Shicheng; Meng, Guangrong; Lalancette, Roger; Szostak, Michal

    2016-09-02

    Amide N-C(O) bonds are generally unreactive in cross-coupling reactions employing low-valent transition metals due to nN → π*C═O resonance. Herein we demonstrate that N-acyl-tert-butyl-carbamates (Boc) and N-acyl-tosylamides (Ts), two classes of acyclic amides that have recently enabled the development of elusive amide bond N-C cross-coupling reactions with organometallic reagents, are intrinsically twisted around the N-C(O) axis. The data have important implications for the design of new amide cross-coupling reactions with the N-C(O) amide bond cleavage as a key step.

  5. Structure of the mercury(II) mixed-halide (Br/Cl) complex of 2,2'-(5-tert-butyl-1,3-phenyl-ene)bis-(1-pentyl-1H-benzo[d]imidazole).

    Science.gov (United States)

    Rani, Varsha; Singh, Harkesh B; Butcher, Ray J

    2017-03-01

    The mercury(II) complex of 2,2'-(5-tert-butyl-1,3-phenyl-ene)bis-(1-pentyl-1H-benz-imidazole), namely catena-poly[[dihalogenido-mercury(II)]-μ-2,2'-(5-tert-butyl-1,3-phenyl-ene)bis-(1-pentyl-1H-benzimidazole)-κ(2)N(3):N(3')], [HgBr1.52Cl0.48(C34H42N4)], 2, has a polymeric structure bridging via the N atoms from the benzimidazole moieties of the ligand. The compound crystallizes in the ortho-rhom-bic space group Pca21 and is a racemic twin [BASF = 0.402 (9)]. The geometry around the Hg(II) atom is distorted tetra-hedral, with the Hg(II) atom coordinated to two N atoms, one Br atom, and a fourth coordination site is occupied by a mixed halide (Br/Cl). For the two ligands in the asymmetric unit, there is disorder with one of the two tert-butyl groups and benzimidazole moieties showing twofold disorder, with occupancy factors of 0.57 (2):0.43 (2) for the tert-butyl group and 0.73 (3):0.27 (3) for the benzimidazole group. In addition, there is threefold disorder for two of the four n-pentyl groups, with occupancy factors of 0.669 (4):0.177 (4):0.154 (4) and 0.662 (4):0.224 (4):0.154 (4), respectively. The mol-ecules form a one-dimensional helical polymer propagating in the b-axis direction. The helices are held together by intra-strand C-H⋯Br and C-H⋯Cl inter-actions. Each strand is further linked by inter-strand C-H⋯Br and C-H⋯Cl inter-actions. In addition, there are weak C-H⋯N inter-strand inter-actions which further stabilize the structural arrangement.

  6. Structure of the mercury(II mixed-halide (Br/Cl complex of 2,2′-(5-tert-butyl-1,3-phenylenebis(1-pentyl-1H-benzo[d]imidazole

    Directory of Open Access Journals (Sweden)

    Varsha Rani

    2017-03-01

    Full Text Available The mercury(II complex of 2,2′-(5-tert-butyl-1,3-phenylenebis(1-pentyl-1H-benzimidazole, namely catena-poly[[dihalogenidomercury(II]-μ-2,2′-(5-tert-butyl-1,3-phenylenebis(1-pentyl-1H-benzimidazole-κ2N3:N3′], [HgBr1.52Cl0.48(C34H42N4], 2, has a polymeric structure bridging via the N atoms from the benzimidazole moieties of the ligand. The compound crystallizes in the orthorhombic space group Pca21 and is a racemic twin [BASF = 0.402 (9]. The geometry around the HgII atom is distorted tetrahedral, with the HgII atom coordinated to two N atoms, one Br atom, and a fourth coordination site is occupied by a mixed halide (Br/Cl. For the two ligands in the asymmetric unit, there is disorder with one of the two tert-butyl groups and benzimidazole moieties showing twofold disorder, with occupancy factors of 0.57 (2:0.43 (2 for the tert-butyl group and 0.73 (3:0.27 (3 for the benzimidazole group. In addition, there is threefold disorder for two of the four n-pentyl groups, with occupancy factors of 0.669 (4:0.177 (4:0.154 (4 and 0.662 (4:0.224 (4:0.154 (4, respectively. The molecules form a one-dimensional helical polymer propagating in the b-axis direction. The helices are held together by intra-strand C—H...Br and C—H...Cl interactions. Each strand is further linked by inter-strand C—H...Br and C—H...Cl interactions. In addition, there are weak C—H...N inter-strand interactions which further stabilize the structural arrangement.

  7. Structure of the mercury(II) mixed-halide (Br/Cl) complex of 2,2′-(5-tert-butyl-1,3-phenyl­ene)bis­(1-pentyl-1H-benzo[d]imidazole)

    Science.gov (United States)

    Rani, Varsha; Singh, Harkesh B.

    2017-01-01

    The mercury(II) complex of 2,2′-(5-tert-butyl-1,3-phenyl­ene)bis­(1-pentyl-1H-benz­imidazole), namely catena-poly[[dihalogenido­mercury(II)]-μ-2,2′-(5-tert-butyl-1,3-phenyl­ene)bis­(1-pentyl-1H-benzimidazole)-κ2 N 3:N 3′], [HgBr1.52Cl0.48(C34H42N4)], 2, has a polymeric structure bridging via the N atoms from the benzimidazole moieties of the ligand. The compound crystallizes in the ortho­rhom­bic space group Pca21 and is a racemic twin [BASF = 0.402 (9)]. The geometry around the HgII atom is distorted tetra­hedral, with the HgII atom coordinated to two N atoms, one Br atom, and a fourth coordination site is occupied by a mixed halide (Br/Cl). For the two ligands in the asymmetric unit, there is disorder with one of the two tert-butyl groups and benzimidazole moieties showing twofold disorder, with occupancy factors of 0.57 (2):0.43 (2) for the tert-butyl group and 0.73 (3):0.27 (3) for the benzimidazole group. In addition, there is threefold disorder for two of the four n-pentyl groups, with occupancy factors of 0.669 (4):0.177 (4):0.154 (4) and 0.662 (4):0.224 (4):0.154 (4), respectively. The mol­ecules form a one-dimensional helical polymer propagating in the b-axis direction. The helices are held together by intra-strand C—H⋯Br and C—H⋯Cl inter­actions. Each strand is further linked by inter-strand C—H⋯Br and C—H⋯Cl inter­actions. In addition, there are weak C—H⋯N inter-strand inter­actions which further stabilize the structural arrangement. PMID:28316824

  8. Mono- and binuclear tris(3-tert-butyl-2-sulfanylidene-1H-imidazol-1-yl)hydroborate bismuth(III) dichloride complexes: a soft scorpionate ligand can coordinate to p-block elements.

    Science.gov (United States)

    Fujisawa, Kiyoshi; Kuboniwa, Ayaka; Kiss, Mercedesz; Szilagyi, Robert K

    2016-11-01

    Tris(pyrazolyl)hydroborate ligands have been utilized in the fields of inorganic and coordination chemistry due to the ease of introduction of steric and electronic substitutions at the pyrazole rings. The development and use of the tris(pyrazolyl)hydroborate ligand, called a `scorpionate', were pioneered by the late Professor Swiatoslaw Trofimenko. He developed a second generation for his ligand system by the introduction of 3-tert-butyl and 3-phenyl substituents and this new ligand system accounted for many remarkable developments in inorganic and coordination chemistry in stabilizing monomeric species while maintaining an open coordination site. Bismuth is remarkably harmless among the toxic heavy metal p-block elements and is now becoming popular as a replacement for highly toxic metal elements, such as lead. Two bismuth(III) complexes of the anionic sulfur-containing tripod tris(3-tert-butyl-2-sulfanylidene-1H-imidazol-1-yl)hydroborate ligand were prepared. By recrystallization from MeOH/CH2Cl2, orange crystals of dichlorido(methanol-κO)[tris(3-tert-butyl-2-sulfanylidene-1H-imidazol-1-yl-κS)hydroborato]bismuth(III), [Bi(C21H34BN6S3)Cl2(CH4O)], (I), were obtained, manifesting a mononuclear structure. By using a noncoordinating solvent, red crystals of the binuclear structure with bridging Cl atoms were obtained, namely di-μ-chlorido-bis{chlorido[tris(3-tert-butyl-2-sulfanylidene-1H-imidazol-1-yl-κS)hydroborato]bismuth(III)}, [Bi2(C21H34BN6S3)2Cl4], (II). These complexes show {Bi(III)S3Cl2O} and {Bi(III)S3Cl3} coordination geometries with average Bi(III)-S bond lengths of 2.73 and 2.78 Å in (I) and (II), respectively. The overall Bi(III) coordination geometry is distorted octahedral due to stereochemically active lone pairs. The three Bi(III)-S bond lengths are almost equal in (I) but show considerable differences in (II), with one long and two shorter distances that also correlate with changes in the UV-Vis and (1)H NMR spectra. For direct measurements

  9. (2S,4′R,5′R-(E-tert-Butyl 2-acetyl-2-(2-oxo-5-phenyl-1,3-dioxolan-4-ylmethyl-5-phenylpent-4-enoate

    Directory of Open Access Journals (Sweden)

    Stuart Warren

    2008-02-01

    Full Text Available The title compound, C27H30O6, was prepared by monodihydroxylation of the bis-olefin (E,E-tert-butyl 2-acetyl-2-cinnamyl-5-phenylpent-4-enoate using standard Sharpless asymmetric dihydroxylation conditions, followed by treatment with 1,1′-carbonyl diimidazole. In the crystal structure, the phenyl rings form an intramolecular edge-to-face C—H...π contact with an interplanar angle of 56.4° and a H...centroid distance of 3.03 Å.

  10. A low-temperature modification of hexa-tert-butyldisilane and a new polymorph of 1,1,2,2-tetra-tert-butyl-1,2-diphenyldisilane.

    Science.gov (United States)

    Scholz, Stefan; Lerner, Hans-Wolfram; Bats, Jan W

    2014-07-01

    Crystals of hexa-tert-butyldisilane, C24H54Si2, undergo a reversible phase transition at 179 (2) K. The space group changes from Ibca (high temperature) to Pbca (low temperature), but the lattice constants a, b and c do not change significantly during the phase transition. The crystallographic twofold axis of the molecule in the high-temperature phase is replaced by a noncrystallographic twofold axis in the low-temperature phase. The angle between the two axes is 2.36 (4)°. The centre of the molecule undergoes a translation of 0.123 (1) Å during the phase transition, but the conformation angles of the molecule remain unchanged. Between the two tri-tert-butylsilyl subunits there are six short repulsive intramolecular C-H···H-C contacts, with H···H distances between 2.02 and 2.04 Å, resulting in a significant lengthening of the Si-Si and Si-C bonds. The Si-Si bond length is 2.6863 (5) Å and the Si-C bond lengths are between 1.9860 (14) and 1.9933 (14) Å. Torsion angles about the Si-Si and Si-C bonds deviate by approximately 15° from the values expected for staggered conformations due to intramolecular steric H···H repulsions. A new polymorph is reported for the crystal structure of 1,1,2,2-tetra-tert-butyl-1,2-diphenyldisilane, C28H46Si2. It has two independent molecules with rather similar conformations. The Si-Si bond lengths are 2.4869 (8) and 2.4944 (8) Å. The C-Si-Si-C torsion angles deviate by between -3.4 (1) and -18.5 (1)° from the values expected for a staggered conformation. These deviations result from steric interactions. Four Si-C(t-Bu) bonds are almost staggered, while the other four Si-C(t-Bu) bonds are intermediate between a staggered and an eclipsed conformation. The latter Si-C(t-Bu) bonds are about 0.019 (2) Å longer than the staggered Si-C(t-Bu) bonds.

  11. Reversible molecular switching at a metal surface: A case study of tetra- tert-butyl-azobenzene on Au(1 1 1)

    Science.gov (United States)

    Wolf, Martin; Tegeder, Petra

    2009-06-01

    Molecular switches represent a fascinating class of functional molecules, whose properties can be reversibly changed between different molecular states by excitation with light or other external stimuli. Using surface science concepts like self assembly to align such molecules in a well-defined geometry at solid surfaces, new functional properties may arise, which are relevant for different fields like, e.g., molecular electronics, sensing or biocompatible interfaces. For a microscopic understanding of molecular switching at surfaces, it is essential to obtain detailed knowledge on the underlying elementary processes, for instance the excitation mechanism in photoinduced switching. Here we present a case study of a specifically designed azobenzene derivative on a metal surface, namely tetra- tert-butyl-azobenzene (TBA) adsorbed on Au(1 1 1), which is so far one of the best studied system for which reversible conformational changes have been demonstrated. TBA/Au(1 1 1) can thus be viewed as model system in order to gain deeper insights into molecular switching processes at metal surfaces. We have studied the photoinduced and thermally activated reversible switching of TBA in direct contact with a Au(1 1 1) surface using two-photon photoemission (2PPE) and high-resolution electron energy loss spectroscopy (HREELS). The trans/cis-isomerization of TBA is accompanied by reversible changes in the geometrical and electronic structure of the molecules, allowing to gain mechanistic and quantitative insight into the switching process. In particular, the cross sections for the photoisomerization, the ratio between the cis- and trans-TBA in the photostationary state, and the activation energy for the thermally induced cis→trans reaction have been determined and are found to be strongly reduced compared to the corresponding quantities in the liquid phase. Furthermore, the mechanism of optical excitation and molecular switching of TBA on Au(1 1 1) has been identified to arise

  12. Gastroprotective Activity of Ethyl-4-[(3,5-di-tert-butyl-2-hydroxybenzylidene) Amino]benzoate against Ethanol-Induced Gastric Mucosal Ulcer in Rats

    Science.gov (United States)

    Halabi, Mohammed Farouq; Shakir, Raied Mustafa; Bardi, Daleya Abdulaziz; Al-Wajeeh, Nahla Saeed; Ablat, Abdulwali; Hassandarvish, Pouya; Hajrezaie, Maryam; Norazit, Anwar; Abdulla, Mahmood Ameen

    2014-01-01

    Background The study was carried out to determine the cytotoxic, antioxidant and gastro-protective effect of ethyl-4-[(3,5-di-tert-butyl-2-hydroxybenzylid ene)amino] benzoate (ETHAB) in rats. Methodology/Principal Findings The cytotoxic effect of ETHAB was assessed using a MTT cleavage assay on a WRL68 cell line, while its antioxidant activity was evaluated in vitro. In the anti-ulcer study, rats were divided into six groups. Group 1 and group 2 received 10% Tween 20 (vehicle). Group 3 received 20 mg/kg Omeprazole. Groups 4, 5 and 6 received ETHAB at doses of 5, 10, and 20 mg/kg, respectively. After an hour, group 1 received the vehicle. Groups 2–6 received absolute ethanol to induce gastric mucosal lesions. In the WRL68 cell line, an IC50 of more than 100 µg/mL was observed. ETHAB results showed antioxidant activity in the DPPH, FRAP, nitric oxide and metal chelating assays. There was no acute toxicity even at the highest dosage (1000 mg/kg). Microscopy showed that rats pretreated with ETHAB revealed protection of gastric mucosa as ascertained by significant increases in superoxide dismutase (SOD), pH level, mucus secretion, reduced gastric lesions, malondialdehyde (MDA) level and remarkable flattened gastric mucosa. Histologically, pretreatment with ETHAB resulted in comparatively better gastric protection, due to reduction of submucosal edema with leucocyte infiltration. PAS staining showed increased intensity in uptake of Alcian blue. In terms of immunohistochemistry, ETHAB showed down-expression of Bax proteins and over-expression of Hsp70 proteins. Conclusion/Significance The gastroprotective effect of ETHAB may be attributed to antioxidant activity, increased gastric wall mucus, pH level of gastric contents, SOD activity, decrease in MDA level, ulcer area, flattening of gastric mucosa, reduction of edema and leucocyte infiltration of the submucosal layer, increased PAS staining, up-regulation of Hsp70 protein and suppressed expression of Bax. Key words

  13. Red Emission of Eu(Ⅲ) Complex Based on 1-(7-(tert-butyl)-9-ethyl-9H-carbazol-2-yl)-4,4,4-trifluorobutane-1,3-dione Excited by Blue Light

    Institute of Scientific and Technical Information of China (English)

    Sheng-gui Liu; Wen-yi Su; Rong-kai Pan; Xiao-ping Zhou

    2012-01-01

    A new Eu(Ⅲ) complex,EuL3(phen),was synthesized,where L is the abbreviation of deprotonated 1-(7-(tert-butyl)-9-ethyl-9H-carbazol-2-yl)-4,4,4-trifluorobutane-1,3-dione (HL),phen is the abbreviation of 1,10-phenanthroline.The Eu(Ⅲ) complex was characterized by element analysis,IR,1H NMR,UV-visible absorption spectroscopy,thermogravimetric analysis (TGA),and photoluminescence measurements (PL).TGA shows that thermal stability of the complex is up to 325 ℃.PL measurement indicates that the Eu(Ⅲ) complex exhibits intense red-emission and extends their excitation bands to visible region.LEDs device was successfully fabricated by precoating complex EuL3(phen) onto 460 nm blue-emitting InGaN chip.The emission of device shows that the complex can act as red phosphor in combination with 460 nm blue-emitting chips.This europium complex based on 1-(7-(tert-butyl)-9-ethyl-9H-carbazol-2-yl)-4,4,4-trifluorobutane-1,3-dione is a kind of interesting red-emitting material excited by blue light,which could avoid the damage of excitation by UV light.

  14. Synthesis and Crystal Structure of N-tert-butyl-N′-(2,4-dichlorobenzoyl)-N-[1-(4-chlorophenyl)-1, 4-dihydro-6-methylpyridazine-4-oxo-3- carbonyl] hydrazine

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The title compound N-tert-butyl-N¢-(2,4-dichlorobenzoyl)-N-[1-(4-chlorophenyl)- 1,4-dihydro-6-methylpyridazine-4-oxo-3-carbonyl]hydrazine [(C23H21N4O3Cl3)2·1.5H2O, Mr = 1042.60] was prepared by the reaction of 1-(4-chlorophenyl)-1,4-dihydro-4-oxo-6- methylpyridazine-3-carboxylic acid with chloroformate ethyl ester, then with N′-tert-butyl-N- (2,4-dichlorobenzoyl) hydrazine in the present of triethylamine. The crystal structure has been determined by X-ray diffraction. The crystal belongs to Monoclinic, space group P21/c, with unit cell constants a =11.4948(9), b=12.7495(10), c=35.854(3) ?, β =92.964(2)°, Z=4, V=5247.6(7) ?3, Dc = 1.320 Mg/m3, F(000) = 2156 , μ (MoKa)= 0.385, R = 0.0661, wR = 0.1875, for 9151 observed reflections( I >2σ(I)). The structure is a dimer linked by intermolecular hydrogen bond which can be observed between N(1)- H…O(6), N(5)- H…O(3). The distances are 2.068 and 2.027? respectively.

  15. Densities, viscosities, speed of sound, and IR spectroscopic studies of binary mixtures of tert-butyl acetate with benzene, methylbenzene, and ethylbenzene at T = (298.15 and 308.15) K

    Energy Technology Data Exchange (ETDEWEB)

    Hasan, Mehdi, E-mail: mihasan@rediffmail.com [P.G. Department of Physical Chemistry, M.S.G. College, Malegaon Camp 423 105 (India); Sawant, Arun B. [P.G. Department of Physical Chemistry, M.S.G. College, Malegaon Camp 423 105 (India); Sawant, Rajashri B. [P.G. Department of Physical Chemistry, M.S.G. College, Malegaon Camp 423 105 (India); Department of Chemistry, S.P.H. Mahila College, Malegaon Camp 423 105 (India); Loke, Pratibha G. [P.G. Department of Physical Chemistry, M.S.G. College, Malegaon Camp 423 105 (India); Department of Physics, G.M.D. Arts, B.W. Commerce and Science College, Sinnar (India)

    2011-09-15

    Highlights: > Densities, viscosities and speed of sound for the benzene + benzenes with tert-butyl acetate at T = (298.15 and 308.15) K is reported. > IR spectra at room temperature are recorded to support observations from other studies. > The experimental observations are explained on the basis of molecular interaction between the constituent binaries. - Abstract: Densities, viscosities, speed of sound, and IR spectroscopy of binary mixtures of tert-butyl acetate (TBA) with benzene, methylbenzene, and ethylbenzene have been measured over the entire range of composition, at (298.15 and 308.15) K and at atmospheric pressure. From the experimental values of density, viscosity, speed of sound, and IR spectroscopy; excess molar volumes V{sup E}, deviations in viscosity {Delta}{eta}, deviations in isentropic compressibility {Delta}{kappa}{sub s} and stretching frequency {nu} have been calculated. The excess molar volumes and deviations in isentropic compressibility are positive for the binaries studied over the whole composition, while deviations in viscosities are negative for the binary mixtures. The excess molar volumes, deviations in viscosity, and deviations in isentropic compressibility have been fitted to the Redlich-Kister polynomial equation. The Jouyban-Acree model is used to correlate the experimental values of density, viscosity, and speed of sound.

  16. Free radical scavenging abilities of flavonoids as mechanism of protection against mutagenicity induced by tert-butyl hydroperoxide or cumene hydroperoxide in Salmonella typhimurium TA102.

    Science.gov (United States)

    Edenharder, R; Grünhage, D

    2003-09-09

    Mutagenicity induced by tert-butyl hydroperoxide (BHP) or cumene hydroperoxide (CHP) in Salmonella typhimurium TA102 was effectively reduced by flavonols with 3',4'-hydroxyl groups such as fisetin, quercetin, rutin, isoquercitrin, hyperoxide, myricetin, myricitrin, robinetin, and to a lesser extent also by morin and kaempferol (ID50=0.25-1.05 micromol per plate). With the exception of isorhamnetin, rhamnetin, morin, and kaempferol, closely similar results were obtained with both peroxides. Hydrogenation of the double bond between carbons 2 and 3 (dihydroquercetin, dihydrorobinetin) as well as the additional elimination of the carbonyl function at carbon 4 (catechins) resulted in a loss of antimutagenicity with the notable exception of catechin itself. Again, all flavones and flavanones tested were inactive except luteolin, luteolin-7-glucoside, diosmetin, and naringenin. The typical radical scavenger butylated hydroxytoluene also showed strong antimutagenicity against CHP (ID50=5.4 micromol per plate) and BHP (ID50=11.4 micromol per plate). Other lipophilic scavengers such as alpha-tocopherol and N,N'-diphenyl-1,4-phenylenediamine exerted only moderate effects, the hydrophilic scavenger trolox was inactive. The metal chelating agent 1,10-phenanthroline strongly reduced mutagenicities induced by CHP and BHP (ID50=2.75 and 2.5 micromol per plate) at low concentrations but induced mutagenic activities at higher concentrations. The iron chelator deferoxamine mesylate, however, was less effective in both respects. The copper chelator neocuproine effectively inhibited mutagenicity induced by BHP (ID50=39.7 micromol per plate) and CHP (ID50=25.9 micrommol per plate), the iron chelator 2,2'-dipyridyl was less potent (ID50=6.25 mmol per plate against BHP, 0.42 mmol per plate against CHP). In the absence of BHP and CHP, yet not in the presence of these hydroperoxides, quercetin, rutin, catechin, epicatechin, and naringenin induced strong mutagenic activities in S

  17. Dynamics of ultrafast intramolecular charge transfer with 1-tert-butyl-6-cyano-1,2,3,4-tetrahydroquinoline (NTC6) in n-hexane and acetonitrile.

    Science.gov (United States)

    Druzhinin, Sergey I; Kovalenko, Sergey A; Senyushkina, Tamara; Zachariasse, Klaas A

    2007-12-20

    The intramolecular charge transfer (ICT) reaction of 1-tert-butyl-6-cyano-1,2,3,4-tetrahydroquinoline (NTC6) in n-hexane and acetonitrile (MeCN) is investigated by picosecond fluorescence experiments as a function of temperature and by femtosecond transient absorption measurements at room temperature. NTC6 in n-hexane is dual fluorescent from a locally excited (LE) and an ICT state, with a quantum yield ratio Phi'(ICT)/Phi(LE) of 0.35 at +25 degrees C and 0.67 at -95 degrees C, whereas in MeCN mainly an ICT emission is observed. From the temperature dependence of Phi'(ICT)/Phi(LE) for NTC6 in n-hexane, an LE/ICT enthalpy difference DeltaH of -2.4 kJ/mol is determined. For comparison, 1-isopropyl-6-cyano-1,2,3,4-tetrahydroquinoline (NIC6) is also investigated. This molecule does not undergo an ICT reaction, because of its larger energy gap DeltaE(S1,S2). From the molar absorption coefficient epsilonmax of NTC6 as compared with other aminobenzonitriles, a ground-state amino twist angle theta of approximately 22 degrees is deduced. The increase of epsilonmax between n-hexane and MeCN indicates that theta decreases when the solvent polarity becomes larger. Whereas single-exponential LE fluorescence decays are obtained for NIC6 in n-hexane and MeCN, the LE and ICT decays of NTC6 in these solvents are double exponential. For NTC6 in n-hexane at -95 degrees C, with a shortest decay time of 20 ps, the forward (ka=2.5x10(10) s(-1)) and backward (kd=2.7x10(10) s(-1)) rate constants for the LEICT reaction are determined from the time-resolved LE and ICT fluorescence spectra. For NTC6 in n-hexane and MeCN, the excited-state absorption (ESA) spectrum at 200 fs after excitation is similar to the LE(ESA) spectra of NIC6 and 4-(dimethylamino)benzonitrile (DMABN), showing that LE is the initially excited state for NTC6. These results indicate that the LE states of NTC6, NIC6, and DMABN have a comparable molecular structure. The ICT(ESA) spectrum of NTC6 in n-hexane and Me

  18. Aerobic Biodegradation of Per-Treated Methyl Tert-Butyl Ether By Ozonation in an Up-Flow-Fixed-Bed Reactor

    Directory of Open Access Journals (Sweden)

    M. Sadeghi

    2009-01-01

    Full Text Available Problem Statement: MTBE is a common pollution of environmental and has become an issue of considerable concern in recent years. It is not readily amenable to remove MTBE by conventional techniques in water treatment. In the present study, the feasibility of the continuous aerobic biodegradation of MTBE, was evaluated in an Up- Flow Fixed Bed Reactor (UFBR. Approach: The UFBR at a constant Hydroulic Retention Time (HRT of 24 h was used as a biological process that receives the intermediates due to partial oxidation of MTBE. The UFBR coupled to ozonation process as a survey system after a primary operation phase that was necessary for creatory of an initial microbial film on the carriers. Residual concentration of MTBE and its major degradation intermediates were measured by gas chromatography. Aqueous concentration of ozone in the reactor and ozone average concentration in off- gas were determined according to the indigo blue method. The COD reduction and BOD5 to COD ratio were selected as biodegradability indexes. Results: Results showed an effective degradation of MTBE in the coupled ozonation-UFBR continuous flow reactor of ten days of operation time. A partial degradation of MTBE in AOPs increases its biodegradation [The BOD5 to COD ratio increased from lowest (0.01 up to a maximum of 0.72] that corresponds to an ozone consumption of 0.62mg per each mg of COD initially present in the solution. The results showed when m. Mol[MTBE]o/m. Mol(o3 = 0.611, the COD removal efficiency was 89% and as this ratio increased up to 1.25, the of COD removal efficiency decreased to 80%. 46-68% removal of the COD was needed before the mixture was considered biodegradable. The highest removal rate of MTBE, 82.91 mg day-1 achieved through out the UFBR runs (87% removal efficiency, In this study, the removal efficiency of MTBE using integrated-process (ozonation followed biological treatment was from 78.5-86.5%. In order to determine of biological removal rate of MTBE, another UFBR system used as a blank reactors. Results showed that the efficiency of the COD removal (by stripping with the biological degradation was 5-8% which implies insignificant biological removal of MTBE without pre-ozonation. Solid produced in the proposed integrated process was 0.27-0.35 kg TSS kg-1 COD removed which is approximately in down range of conventional biological system (0.3-0.5 kg TSS kg-1COD. Conclusion: Present study showed that we can treatment of the polluted aqueous solutions to MTBE without microbial incubation used to integrated process.

  19. Methyl tert-butyl ether (MTBE) detected in abnormally high concentrations in postmortem blood and urine from two persons found dead inside a car containing a gasoline spill.

    Science.gov (United States)

    Karinen, Ritva; Vindenes, Vigdis; Morild, Inge; Johnsen, Lene; Le Nygaard, Ilah; Christophersen, Asbjørg S

    2013-09-01

    Two deep frozen persons, a female and a male, were found dead in a car. There had been an explosive fire inside the car which had extinguished itself. On the floor inside the car were large pools of liquid which smelled of gasoline. The autopsy findings and routine toxicological analyses could not explain the cause of death. Carboxyhemoglobin levels in the blood samples were gasoline as a fuel oxygenate. Gasoline poisoning is likely to be the cause of the death in these two cases, and MTBE can be a suitable marker of gasoline exposure, when other volatile components have vaporized.

  20. (6R-2-tert-Butyl-6-[(4R,5S-3-isopropyl-4-methyl-5-phenyloxazolidin-2-yl]phenol

    Directory of Open Access Journals (Sweden)

    Takaoki Koyanagi

    2010-04-01

    Full Text Available In the title compound, C23H31NO2, the lone pair on the nitrogen atom is oriented to facilitate intramolecular hydrogen bonding with the hydroxy group residing on the phenyl substituent. The five-membered ring adopts an envelope confornmation with the O atom at the flap. The absolute stereochemistry was verified by measurement of optical activity using a digital polarimeter.

  1. 微通道反应器内叔丁醇溴化反应工艺研究%RESEARCH ON BROMINATION OF tert-BUTYL ALCOHOL IN MICRO-CHANNEL REACTOR

    Institute of Scientific and Technical Information of China (English)

    张跃; 郭欣桐; 严生虎; 刘建武; 沈介发

    2013-01-01

    The preparation of tert-butyl bromide from tert-buthl alcohol through bromination reaction in the micro-channel reactor was presented. Effects as the molar ratio of two materials, the reaction temperature, the catalyst dosage and the resident time on bromination reaction were studied as well. The optimum conditions were obtained as follows: reaction temperature 50 ℃ , the molar ratio of tert-butyl alcohol, hydrobromic acid and concentrated sulphuric acid 1: 1. 5:1, the resident time 60 s. The conversion of fen-butyl alcohol and the selectivity of tert-butyl bromide under these conditions were 92. 3% and 99. 1% respectively, while the corresponding results are 88. 3% and 86. 5% respectively when the reaction was carried out in the batch stirred tank reactor under the same conditions. Compared to the traditional process, the use of micro-channel technology can not only improve the efficacy of the reaction, but also lower the demands of the reaction conditions and reduce the generation of waste acid. Thus, the production efficiency can be greatly improved.%研究了微通道反应器中叔丁醇的溴化反应制备溴代叔丁烷的工艺过程,考察了原料摩尔配比、反应温度、催化剂浓硫酸的用量、停留时间等单因素对反应的影响.通过实验结果得到了较佳的工艺条件:反应温度为50℃,叔丁醇、氢溴酸和浓硫酸的摩尔比为1∶1.5∶1,停留时间60 s,叔丁醇的转化率为92.3%,溴代叔丁烷的选择性为99.1%,传统间歇搅拌反应器中叔丁醇转化率为88.3%,溴代叔丁烷选择性为86.5%.相较于传统工艺方法,利用微通道技术提高了反应效果,降低了反应条件的要求,减少了废酸的产生,大大提高了生产效率.

  2. Surface Properties of the Microgels Based on N-isopropylacrylamide and Tert-butyl Acrylate by Using N, N'-methylene-bis(acrylamide) and Clay as Cross-linker

    Institute of Scientific and Technical Information of China (English)

    ZHANG Qing-song; LU Ping; ZHA Liu-sheng; MA Jing-hong; LIANG Bo-run

    2006-01-01

    Adopting N, N'-methylene-bis (acrylamide) (MBA) and inorganic clay (hectorite) as chemical and physical crosslinking agent, respectively, a series temperature sensitive microgels, based on N-isopropylacrylamide (NIPAM) as a main monomer and tert-butyl acrylate (tBA) as a comonomer were synthesized by surfactant-free emulsion polymerization (SFEP). The microgel particle size and morphology was investigated by means of Atomic Force Microscope (AFM). The surface tension of latex particles was measured by OCA 40 Micro Video based contact angle measuring device. The results showed that the particle size of the microgels with clay as cross-linker was smaller than that using MBA as chemical cross-linker, but exterior morphology of physical microgels is not as clean and neat as chemical microgels. In general, surface tension decreases with increasing hydrophobic tBA content. These smart microgels varied with temperature have the potential applications in the field of drug delivery and intelligent gel fiber.

  3. Synthesis and characterization of amphiphilc block copolymer poly(methyl acrylic acid)-block-polytetrahydrofuran

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Under the specially designated condition the polymerization of both tetrahydrofuran (THF) and tert-butyl methacrylate (tBMA) is a living one. The diblock copolymer, poly(tert-butyl methacrylate)-block-polytetrahydrofuran (PtBMA-b-PTHF), was successfully synthesized by means of the coupling reaction of living cationic PTHF+, SbF6- with living anionic PtBMA-, Li+. LiCl, which has a beneficial effect on the molecular weight distribution (MWD) in the anionic polymerization of (meth)acrylates, hinders the coupling reaction of living chains and cannot be used in the preparation of tBMA precursor. The hydrolysis of the aforementioned diblock copolymer under acid condition results in the amphiphilic diblock copolymer, i.e. poly(methyl acrylic acid)-block-polytetra- hydrofuran (PMAA-b-PTHF). The diblock copolymers were characterized with GPC and IR.

  4. Enzymatic C-demethylation of 1-[2-(5-tert-butyl-[1,3,4] oxadiazole-2-carbonyl)-4-fluoro-pyrrolidin-1-yl]-2-(2-hydroxy-1,1-dimethyl-ethylamino)-ethanone (LC15-0133) in rat liver microsomes.

    Science.gov (United States)

    Yoo, Hye Hyun; Chung, Hye Jin; Lee, Jaeick; Lee, Chang-Seok; Kang, Min Jung; Kim, Dong-Hyun

    2008-03-01

    The in vitro metabolism of 1-[2-(5-tert-butyl-[1,3,4] oxadiazole-2-carbonyl)-4-fluoro-pyrrolidin-1-yl]-2-(2-hydroxy-1,1-dimethyl-ethylamino)-ethanone (LC15-0133), a novel dipeptidyl peptidase-4 inhibitor, was investigated using a hepatic microsomal system. The structures of the metabolites were characterized using mass spectral analysis and by comparison with synthetic references. The in vitro incubation of LC15-0133 with rat liver microsomes resulted in the formation of six metabolites, with the major metabolic reactions being hydroxylation and carbonyl reduction. Of the metabolites, a C-demethylated metabolite (M4) was identified, but was only detected in rat liver microsomes; experimental evidence revealed that the C-demethylated metabolite was generated by nonenzymatic decarboxylation of the carboxyl metabolite (M1). Nonenzymatic decarboxylation is postulated to occur due to the resonance stabilization by the oxadiazole ring attached to the tert-butyl moiety.

  5. Synthesis and Characterization of Novel (E-tert-butyl 7-(4-methoxyphenyl-5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-ylhept-2-enoate and (E-diethyl (6-(4-methoxyphenyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-ylhex-1-en-1-ylphosphonate; Application of Olefin Cross Metathesis

    Directory of Open Access Journals (Sweden)

    *H. Hussain

    2013-12-01

    Full Text Available Two novel compounds (E-tert-butyl 7-(4-methoxyphenyl-5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-ylhept-2-enoate and (E-diethyl (6-(4-methoxyphenyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-ylhex-1-en-1-ylphosphonate were synthesized in excellent yields by olefin cross metathesis (CM. 3-(4-methoxyphenylpropyl diisopropylcarbamate and allylboronic acid pinacol ester were reacted in the presence of s-BuLi/N,N,N,N-tetramethylethyllenediamine (TMEDA to form sec. boronic ester which was further reacted with tert-butyl acrylate and diethyl vinylphosphonate respectively to get the desired products. Both novel compounds have applications as reactants for cyclopropanation and cyclopentataion for asymmetric synthesis.

  6. A Study of the Curing and Flammability Properties of Bisphenol A Epoxy Diacrylate Resin Utilizing a Novel Flame Retardant Monomer, bis[di-acryloyloxyethyl]-p-tert-butyl-phenyl Phosphate

    Directory of Open Access Journals (Sweden)

    Syang-Peng Rwei

    2017-02-01

    Full Text Available A UV-curable, flame-retardant monomer, DAPP (bis[di-acryloyloxyethyl]-p-tert-butyl-phenyl-phosphate, was synthesized based on BPDCP (4-tert-butylphenyl-dichloro phosphate and HEA (2-hydroxy ethyl acrylate. DAPP was blended with regular bisphenol A epoxy acrylate (BAEA in various ratios to yield various phosphorus contents. The TGA-IR (thermogravimetric analyzer interface with an infrared spectrometer results demonstrate that compounding 30 mol % DAPP with BAEA significantly reduced the amount of released CO gas. In contrast, the peak intensity of CO2 is independent of phosphorus content. The limiting oxygen index (LOI, reaching the saturated value of 26, and the heat release rate (HRR measured using a cone-calorimeter, 156.43 KW/m2, confirm the saturation point when 30 mol % DAPP was compounded into BAEA. A study of the kinetics of pyrolysis reveals that Ea decreases as the phosphorus content increases. Both the TGA-IR and pyrolysis results reveal that the phosphorus compound DAPP is easily decomposed during the initial stage of burning to form an insulating layer, which inhibits further burning of the resin and the consequent release of other flammable gases.

  7. Synthesis and characterization of 3-amine-4-( tert-butyl amine ) azoxy-furazane%3-氨基-4-(叔丁基氧化偶氮基)呋咱的合成与表征

    Institute of Scientific and Technical Information of China (English)

    李祥志; 王伯周; 李辉; 李亚南; 毕福强

    2012-01-01

    The 3-amino-4-( tert-butyl amine ) azoxyfurazane was synthesized using 3, 4-diaminofurazan via oxidation and condensation with the total yield of 37. 6% . The title compound and intermediate were characterized by 1HNMR, IR, MS and elementary analysis. The conditions of condensation were optimized such as cuprous chloride as catalyst and the reaction time of 16 h and temperature of 15 ~ 25 ℃ . The yield can reach 73. 5% .%以3,4-二氨基呋咱( DAF)为起始原料,苯为反应介质,经Caro's酸氧化得到3-氨基-4-亚硝基呋咱,然后与N,N-二溴-叔丁基胺缩合得到标题化合物,总收率37.6%,并采用红外光谱、核磁共振、元素分析及质谱等进行了结构表征.优化了反应条件,确定适宜的反应条件为:氯化亚铜作为催化剂,反应时间16h,温度15 ~ 25℃,收率73.5%.

  8. Renal histopathology in toxicity and carcinogenicity studies with tert-butyl alcohol administered in drinking water to F344 rats: a pathology working group review and re-evaluation.

    Science.gov (United States)

    Hard, Gordon C; Bruner, Richard H; Cohen, Samuel M; Pletcher, John M; Regan, Karen S

    2011-04-01

    An independent Pathology Working Group (PWG) re-evaluated the kidney changes in National Toxicology Program (NTP) toxicology/carcinogenicity studies of tert-butyl alcohol (TBA) in F344/N rats to determine possible mode(s) of action underlying renal tubule tumors in male rats at 2-years. In the 13-week study, the PWG confirmed that the normal pattern of round hyaline droplets in proximal convoluted tubules was replaced by angular droplet accumulation, and identified precursors of granular casts in the outer medulla, changes typical of alpha(2u)-globulin (α(2u)-g) nephropathy. In the 2-year study, the PWG confirmed the NTP observation of increased renal tubule tumors in treated male groups. Linear papillary mineralization, another hallmark of the α(2u)-g pathway was present only in treated male rats. Chronic progressive nephropathy (CPN) was exacerbated in high-dose males and females, with a relationship between advanced grades of CPN and renal tumor occurrence. Hyperplasia of the papilla lining was a component of CPN in both sexes, but there was no pelvic urothelial hyperplasia. High-dose females showed no TBA-related nephrotoxicity. The PWG concluded that both α(2u)-g nephropathy and exacerbated CPN modes of action were operative in TBA renal tumorigenicity in male rats, neither of which has relevance for human cancer risk.

  9. Synthesis and Fungicidal Activity of 5-Aryl-1-(aryloxyacetyl)-3-(tert-butyl or phenyl)-4-(1H-1,2,4-triazol-1-yl)-4,5-Dihydropyrazole

    Institute of Scientific and Technical Information of China (English)

    毛会玉; Hong; SONG; SHI; Deqing

    2014-01-01

    A series of novel 5-aryl-1-(aryloxyacetyl)-3-(tert-butyl or phenyl)-4-(1H-1,2,4-triazol-1-yl)-4,5-dihydropyrazole 3a-3n were synthesized by the annulation of 2-aryloxyacetohydrazides with 3-aryl-1-t-butyl(or phenyl)-2-(1H-1,2,4-triazol-1-yl)prop-2-en-1-ones(1)in the presence of a catalytic amount of acetic acid.Compounds 2 were obtained by the Knoevenagel reactions of 1-t-butyl(or phenyl)-2-(1H-1,2,4-triazol-1-yl)ethanone(2)with aromatic aldehydes in the presence of piperidine.Their structures were confirmed by IR,1H-NMR,ESIMS,and elemental analyses.The preliminary bioassay indicated that some compounds displayed moderate to excellent fungicidal activity.For example,compounds 31,3m,and 3n possessed100%inhibition against Cercospora arachidicola Hori at the concentration of 50 mg/L.

  10. Vibrational Spectroscopy Investigation Using Ab Initio and Density Functional Theory Analysis on the Structure of tert-Butyl 3a-Chloroperhydro-2,6a-epoxyoxireno[e]isoindole-5-carboxylate

    Directory of Open Access Journals (Sweden)

    Hakan Arslan

    2013-01-01

    Full Text Available The molecular structure, vibrational frequencies, and infrared intensities of the tert-butyl 3a-chloroperhydro-2,6a-epoxyoxireno[e]isoindole-5-carboxylate were calculated by the HF and DFT (BLYP and B3LYP methods using 6-31G(d and 6-31G(d,p basis sets. The FT infrared spectrum of the solid sample was measured under standard condition. We obtained two stable conformers for the title compound; however Conformer 1 is approximately 0.2 kcal/mol more stable than the Conformer 2. The comparison of the theoretical and experimental geometry of the title compound shows that the X-ray parameters fairly well reproduce the geometry of Conformer 2. Comparison of the observed fundamental vibrational frequencies of the title molecule and calculated results by HF and DFT methods indicates that B3LYP is superior for molecular vibrational problems. The harmonic vibrations computed by the B3LYP/6-31G(d,p method are in a good agreement with the observed IR spectral data. Theoretical vibrational spectra of the title compound were interpreted by means of potential energy distributions (PEDs using VEDA 4 program.

  11. Quantum mechanical study and spectroscopic (FT-IR, FT-Raman, UV-Visible) study, potential energy surface scan, Fukui function analysis and HOMO-LUMO analysis of 3-tert-butyl-4-methoxyphenol by DFT methods.

    Science.gov (United States)

    Saravanan, S; Balachandran, V

    2014-09-15

    This study represents an integral approach towards understanding the electronic and structural aspects of 3-tert-butyl-4-methoxyphenol (TBMP). Fourier-transform Infrared (FT-IR) and Fourier-transform Raman (FT-Raman) spectra of TBMP was recorded in the region 4000-400 cm(-1) and 3500-100 cm(-1), respectively. The molecular structures, vibrational wavenumbers, infrared intensities and Raman activities were calculated using DFT (B3LYP and LSDA) methods using 6-311++G (d,p) basis set. The most stable conformer of TBMP was identified from the computational results. The assignments of vibrational spectra have been carried out with the help of normal co-ordinate analysis (NCA) following the scaled quantum mechanical force field (SQMFF) methodology. The first order hyperpolarizability (β0) and related properties (β, α0 and Δα) of TBMP have been discussed. The stability and charge delocalization of the molecule was studied by Natural Bond Orbital (NBO) analysis. UV-Visible spectrum and effects of solvents have been discussed and the electronic properties such as HOMO and LUMO energies were determined by time-dependent TD-DFT approach with B3LYP/6-311++G (d,p) level of theory. The molecule orbital contributions are studied by density of energy states (DOSs). The reactivity sites are identified by mapping the electron density into electrostatic potential surface (MEP). Mulliken analysis of atomic charges is also calculated. The thermodynamic properties at different temperatures were calculated, revealing the correlations between standard heat capacities, standard entropy and standard enthalpy changes with temperatures. Global hardness, global softness, global electrophilicity and ionization potential of the title compound are determined. Copyright © 2014 Elsevier B.V. All rights reserved.

  12. In Vitro Formation of 8-hydroxy-2-deoxyguanosine (8-OHdG in Calf Thymus DNA upon Treatment of 2-deoxyguanosine with Propyl Gallate and 2,6-di-tert-butyl-p-benzoquinone

    Directory of Open Access Journals (Sweden)

    Budiawan Budiawan

    2015-12-01

    Full Text Available Oxidative DNA damage caused by propyl gallate (PG and 2,6-di-tert-butyl-p-benzoquinone (BHT-quinone, a metabolite of butylated hydroxytoluene (BHT was analyzed from the 8-hydroxy-2¢-deoxyguanosine (8-OHdG formation in calf thymus DNA and DNA base, 2¢-deoxyguanosine (dG. PG in the presence of CuCl2 increased the 8-OHdG formation in calf thymus DNA by around 9.17 times as compared to the control (untreated DNA. In the presence of CuCl2 at 1.28×10-5 M, the 8-OHdG per dG ratio resulting from the reaction of dG with PG at various concentrations (20–150 ppm ranged from 75.50 to 312.06 8-OHdG per 105 dG. The 8-OHdG formation increased when the PG concentration was increased from 20 ppm to 80 ppm, and then, it began to plateau around 80 ppm. On the other hand, BHT-quinone increased the formation of 8-OHdG in the presence of CuCl2 by 0.05 times as compared to the control (untreated DNA. LC-MS/MS analysis was used to identify the molecular structure of 8-OHdG, which had a base peak (M+. + 1 at m/z = 284 and two main fragments at m/z = 167.9 and m/z = 139.9.

  13. Simultaneous liquid-liquid extraction of dibenzyl disulfide, 2,6-di-tert-butyl-p-cresol, and 1,2,3-benzotriazole from power transformer oil prior to GC and HPLC determination.

    Science.gov (United States)

    Jaber, Abdul Muttaleb Yousef; Mehanna, Nemr Ahmed; Abulkibash, Abdalla Mahmoud

    2012-03-01

    2,6-Di-tert-butyl-p-cresol (DBPC), dibenzyl disulfide (DBDS), and 1,2,3-benzotriazole (BTA) are additives that may be found concomitantly in the oil matrix of power transformer. DBPC and DBDS act as antioxidants while, BTA is a corrosion inhibitor that protects copper conductors inside the transformer unit from corrosion. A powerful analytical method is, therefore, required to determine these additives at trace levels in the transformer oil. This work describes a unique single liquid-liquid extraction pretreatment step prior to the determination of the components by gas chromatography (GC) and high-performance liquid chromatography (HPLC) techniques. The optimum volume ratio used in the pretreatment step was determined as 5:2:5 for mineral oil/n-hexane/acetonitrile, respectively. Relatively, the method is simple and quick with a minimal use of solvents. Analytical results indicate that the method is relatively sensitive, accurate, and precise for each of the three components in fresh and used mineral oil. The calibration curves for the three components demonstrate a significant increase in sensitivities. Detection limits found were, 100 mg L(-1) (0.01% w/v), 0.80 mg L(-1) , and 2.04 mg L(-1) for DBPC, DBDS, and BTA, respectively. The Student's t values determined at 95% confidence level indicate that there is no significant difference between the experimental means obtained by this method and the standard method for each component. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Substrate selectivity in the low temperature atomic layer deposition of cobalt metal films from bis(1,4-di-tert-butyl-1,3-diazadienyl)cobalt and formic acid

    Science.gov (United States)

    Kerrigan, Marissa M.; Klesko, Joseph P.; Rupich, Sara M.; Dezelah, Charles L.; Kanjolia, Ravindra K.; Chabal, Yves J.; Winter, Charles H.

    2017-02-01

    The initial stages of cobalt metal growth by atomic layer deposition are described using the precursors bis(1,4-di-tert-butyl-1,3-diazadienyl)cobalt and formic acid. Ruthenium, platinum, copper, Si(100), Si-H, SiO2, and carbon-doped oxide substrates were used with a growth temperature of 180 °C. On platinum and copper, plots of thickness versus number of growth cycles were linear between 25 and 250 cycles, with growth rates of 0.98 Å/cycle. By contrast, growth on ruthenium showed a delay of up to 250 cycles before a normal growth rate was obtained. No films were observed after 25 and 50 cycles. Between 100 and 150 cycles, a rapid growth rate of ˜1.6 Å/cycle was observed, which suggests that a chemical vapor deposition-like growth occurs until the ruthenium surface is covered with ˜10 nm of cobalt metal. Atomic force microscopy showed smooth, continuous cobalt metal films on platinum after 150 cycles, with an rms surface roughness of 0.6 nm. Films grown on copper gave rms surface roughnesses of 1.1-2.4 nm after 150 cycles. Films grown on ruthenium, platinum, and copper showed resistivities of oxidation of the cobalt, with cobalt metal underneath. Analogous analysis of a film grown with 150 cycles on a copper substrate showed cobalt oxide throughout the film. No film growth was observed after 1000 cycles on Si(100), Si-H, and carbon-doped oxide substrates. Growth on thermal SiO2 substrates gave ˜35 nm thick layers of cobalt(ii) formate after ≥500 cycles. Inherently selective deposition of cobalt on metallic substrates over Si(100), Si-H, and carbon-doped oxide was observed from 160 °C to 200 °C. Particle deposition occurred on carbon-doped oxide substrates at 220 °C.

  15. High functional nano materials for ophthalmic lenses containing silicon 2,3-naphthalocyanine bis(trihexylsilyloxide) and silicon 2,9,16,23-tetra-tert-butyl-29H31 H-phthalocyanine dihydroxide.

    Science.gov (United States)

    Sung, A-Young; Kim, Tae-Hun

    2014-11-01

    High functional ophthalmic lens materials, poly(HEMA-co-GMA)s were prepared by the copolymerization of HEMA, MMA, NVP, EDGMA and GMA in the presence of SiNc [silicon 2,3-naphthalocyanine bis(trihexylsilyloxide)] and SiPc (silicon 2,9,16,23-tetra-tert-butyl-29H31H-phthalocyanine dihydroxyde). Also, the physical and optical characteristics of the produced polymers were analyzed to investigate UV-blocking capabilities of these functional ophthalmic dyes and their applicability as materials for colored hydrogel contact lenses. For G_SN samples to which GMA was added to the Ref._SN combination, the transmittance for visible ray, UV-B and UV-A was in the range of 86.0-89.4%, 63.0-67.6% and 62.5-66.0% respectively. Also, for G_SP samples, the transmittance for visible ray, UV-B and UV-A was in the range of 85.2-87.0%, 70.0-72.6 and 68.0-70.2% respectively. The measurement of the spectral transmittance showed that both SiNc and SiPc absorbed a small amount of UV light, but the absorption pattern for UV light differed for each material. Based on the results, the addition of SiNc and SiPc to ophthalmic polymer materials can be used for various purposes in colored ophthalmic lens that are capable of offering protection from UV and infrared light without significant change of the physical properties.

  16. EFFECT OF DE-tert-BUTYLATION AND FUNCTIONALIZATION WITH AMINE GROUPS AT THE UPPER RIM OF p-tert-BUTYLCALIX[4]ARENE TO THE EXTRACTABILITY FOR Cr3+, Cd2+ and Pb2+ IONS

    Directory of Open Access Journals (Sweden)

    Firdaus Firdaus

    2010-06-01

    Full Text Available The effects to the extractability forwards Cr3+, Cd2+, and Pb2+ ions of de-tert-butylation and functionalization with amine groups at the upper rim of p-tert-butylcalix[4]arene had been studied by applied the p-tert-butylcalix[4]arene (1, tetrahydroxycalix[4]arene (2, and p-(aminobutoxycalixarene (3 compounds as extractants for the heavy metals ions. The extraction involved optimise of three parameters, i.e. pH, time, and concentration of extractants. The extraction degrees of the heavy metals ions at optimum conditions were compared each other to decide the effects. Compound 1 showed high extractability to Cr3+ and Pb2+ ions over Cd2+ ion, but compound 2 as the debutylated product of compound 1 showed low extractability to the all of the heavy metals ions. Compound 3 as product of etherification with butyl groups of the lower rim followed functionalization with amine groups of the upper rim of compound 1 showed high extractability to Pb2+, but low to Cr3+ and Cd2+. Pursuant to the facts it was concluded that debutylation of compound 1 to compound 2 causing decrease drastically of extractability to the heavy metals ions; functionalization of the upper with amine groups as ionophore (compound 3 causing increase of the extractability to Pb2+ ion and decrease of the extractability to Cr3+ with increasing of separation factor value β(Pb2+/Cr3+ from 1.74 by compound 1 to 48.00 by compound 3. By slope analysis, the extracted species and mechanisms of the extractions have been confirmed.   Keywords: p-tert-butylcalix[4]arene, debutylation, p-(aminobutoxycalix[4]arene, extractability, heavy metals, extraction mechanisms.

  17. Valence and spin situations in isomeric [(bpy)Ru(Q')2]n (Q' = 3,5-di-tert-butyl-N-aryl-1,2-benzoquinonemonoimine). An experimental and DFT analysis.

    Science.gov (United States)

    Das, Dipanwita; Mondal, Tapan Kumar; Chowdhury, Abhishek Dutta; Weisser, Fritz; Schweinfurth, David; Sarkar, Biprajit; Mobin, Shaikh M; Urbanos, Francisco A; Jiménez-Aparicio, Reyes; Lahiri, Goutam Kumar

    2011-09-07

    The article deals with the ruthenium complexes, [(bpy)Ru(Q')(2)] (1-3) incorporating two unsymmetrical redox-noninnocent iminoquinone moieties [bpy = 2,2'-bipyridine; Q' = 3,5-di-tert-butyl-N-aryl-1,2-benzoquinonemonoimine, aryl = C(6)H(5) (Q'(1)), 1; m-Cl(2)C(6)H(3) (Q'(2)), 2; m-(OCH(3))(2)C(6)H(3) (Q'(3)), 3]. 1 and 3 have been preferentially stabilised in the cc-isomeric form while both the ct- and cc-isomeric forms of 2 are isolated [ct: cis and trans and cc: cis and cis with respect to the mutual orientations of O and N donors of two Q']. The isomeric identities of 1-3 have been authenticated by their single-crystal X-ray structures. The collective consideration of crystallographic and DFT data along with other analytical events reveals that 1-3 exhibit the valence configuration of [(bpy)Ru(II)(Q'(Sq))(2)]. The magnetization studies reveal a ferromagnetic response at 300 K and virtual diamagnetic behaviour at 2 K. DFT calculations on representative 2a and 2b predict that the excited triplet (S = 1) state is lying close to the singlet (S = 0) ground state with singlet-triplet separation of 0.038 eV and 0.075 eV, respectively. In corroboration with the paramagnetic features the complexes exhibit free radical EPR signals with g∼2 and (1)HNMR spectra with broad aromatic proton signals associated with the Q' at 300 K. Experimental results in conjunction with the DFT (for representative 2a and 2b) reveal iminoquinone based preferential electron-transfer processes leaving the ruthenium(ii) ion mostly as a redox insensitive entity: [(bpy)Ru(II)(Q'(Q))(2)](2+) (1(2+)-3(2+)) ⇋ [(bpy)Ru(II)(Q(')(Sq))(Q(')(Q))](+) (1(+)-3(+)) ⇋ [(bpy)Ru(II)(Q(')(Sq))(2)] (1-3) ⇋ [(bpy)Ru(II)(Q(')(Sq))(Q(')(Cat))](-)/[(bpy)Ru(III)(Q(')(Cat))(2)](-) (1(-)-3(-)). The diamagnetic doubly oxidised state, [(bpy)Ru(II)(Q'(Q))(2)](2+) in 1(2+)-3(2+) has been authenticated further by the crystal structure determination of the representative [(bpy)Ru(II)(Q'(3))(2)](ClO(4))(2) [3](ClO(4

  18. N-tert-Butyl-2-methylpropanamide

    Directory of Open Access Journals (Sweden)

    Kelly A. Kluge

    2011-08-01

    Full Text Available The title compound, C8H17NO, crystallizes with two independent molecules in the asymmetric unit. In the crystal, intermolecular N—H...O hydrogen bonding is observed between neighboring molecules, forming continuous molecular chains along the c-axis direction.

  19. [Chemical analytical aspects of hygiene safety of the use of methyl tertiary-butyl ether in the production of gasoline].

    Science.gov (United States)

    Malysheva, A G; Rastyannikov, E G; Kozlova, N Yu; Artyushina, I Yu

    2014-01-01

    There was developed, certified and recommended for the practical application the technique for control in the water used as a high-octane oxygenated gasoline additive methyl tert-butyl ether with the use of chromatography-mass spectrometry method with a sensitivity of (0.005 mg/dm3) below the level of existing foreign regulations. Technique is introduced into the Federal Information Fund to ensure the unity of measurements. The possibility of applying the proposed method of analysis for monitoring chemical contamination of water sources and the quality control and safety of drinking water has been shown.

  20. Simultaneous Determination of Tert-Butyl Hydroquinone and Butylated Hydroxyanisole in Foods by High Performance Liquid Chromatography with Fluorimetric Detection%反相高效液相色谱-荧光法同时测定食品中叔丁基对苯二酚和叔丁基羟基茴香醚的含量

    Institute of Scientific and Technical Information of China (English)

    徐琴; 汤志旭; 林洪; 江志刚; 牟志春

    2008-01-01

    油溶性抗氧化剂叔丁基对苯二酚(tert-butyl hydroquinone,TBHQ)、叔丁基羟基茴香醚(butylated hydroxyanisole,BHA)和2,6-二叔丁基对甲酚(butylated hydroxytoluene,BHT)是目前最常用的化学合成抗氧化剂,能够有效阻止或延迟油脂氧化变质。然而TBHQ、BHA和BHT均具有一定的急性毒性和慢性致癌作用,过量添加会损害人体健康,

  1. 地下水曝气法处理土壤及地下水中甲基叔丁基醚(MTBE)%Removal of Methyl Tert- Butyl Ether (MTBE) in Saturated Soil and Groundwater Using Air Sparging Technique

    Institute of Scientific and Technical Information of China (English)

    郑艳梅; 王战强; 黄国强; 姜斌; 李鑫钢

    2004-01-01

    通过建立 AS地下水曝气( air sparging ,AS)实验装置,研究了 MTBE的去除效果,并进行了不同曝气流量的实验研究.结果显示,用 AS法修复 MTBE 污染的饱和土壤和地下水,其去除率可以达到 95%.对不同曝气流量下的 MTBE去除效果进行比较,得到用 AS法修复 MTBE污染地下水的最佳操作条件,实验中最佳曝气流量为 0.1 m3· h-1.

  2. 用上流式生物反应器降解甲基叔丁基醚%Degradation of Methyl tert-Butyl Ether in Up-flow Bioreactor

    Institute of Scientific and Technical Information of China (English)

    谢国建; 张丽丽; 陈建孟; 何小峰

    2007-01-01

    用上流式生物反应器(UFBR)降解甲基叔丁基醚(MTBE),研究了水力停留时间(HRT)和进水中MTBE质量浓度对MTBE去除率的影响.实验结果表明:在进水中MTBE质量浓度为25 mg/L、HRT为18.6 h的条件下,MTBE的去除率为84.13 %;在HRT为18.6 h、进水中MTBE质量浓度低于15 mg/L的条件下,MTBE的去除率达92 %以上.,UFBR符合Eckenfelder动力学模型.

  3. The synthesis and spectroscopic study of stable free radicals related to piperidine-n-oxyl, including a stable bi-radical; Syntheses et etudes spectroscopiques de radicaux libres piperidiniques et d'un biradical stable, du type nitroxyde

    Energy Technology Data Exchange (ETDEWEB)

    Briere, R. [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires, Laboratoire de chimie organique physique

    1967-06-01

    A new synthesis of di-tert-butyl nitroxide using the reaction between tert-butyl magnesium chloride and nitro-tert-butane is presented in the first section. Synthesis and investigation of stable free piperidine-N-oxyl radicals are described in the second section. All these nitroxides have been characterised by their I. R., U. V. and E. P. R. absorption spectra. The final section contains a description of the synthesis of a stable bi-radical of the nitroxide type by condensation of 2,2, 6, 6-tetramethyl-piperid-4-one-l-oxyl with hydrazine. (author) [French] La premiere partie expose une nouvelle methode de synthase du di-t-butyl nitroxyde, par action d'halogenures de t-butyl magnesium sur le nitro-t-butane (Rdt maximum 45 pour cert, purete 86 pour cent). Une etude de radicaux. libres stables pipericliniques est faite dans une seconde partie. Ces composes sont obtenus par oxydation de derives de la triacetonamine. Les caracteristiques spectroscopiques ultra-violette, infra-rouge, et paramagnetique electronique de ces radicaux sont donnees. La grande inertie chimique du groupement nitroxyde a permis la syn-these d'un biradical stable par formation d'azine d'une cetone radicalaire, ce qui fait 1'objet de la troisieme partie. (auteur)

  4. 银杏叶提取物对叔丁基过氧化氢损伤人脐带间充质干细胞的干预作用%Intervention of Tert-butyl Hydroperoxide-Induced Injury in Human Umbilical Cord Derived Mesenchymal Stem Cells with Ginkgo Biloba Extract

    Institute of Scientific and Technical Information of China (English)

    袁茵; 王辉; 鲁欣

    2015-01-01

    Objective To observe the intervention effect of Ginkgo biloba extract EGb761 on tert-butyl hydroperoxide ( t-BHP)-induced injury in human umbilical cord-derived mesenchymal stem cells ( hUC-MSCs) . Methods Proliferation of hUC-MSCs after primary culture was detected by methyl thiazolyl tetrazolium (MTT) assay, and then the optimal concentrations of t-BHP and EGb761 for oxidative stress injured MSC model were screened. Cell apoptosis was assessed by flow cytometry after Annexin V-fluorescein isothiocyanatel propidium iodide ( Annexin V-FITC/PI) staining. Content of malondialdehyde ( MDA) and superoxide dismutase (SOD) activity in hUC-MSCs were evaluated, and the expression levels of p53 and p21Cip1/Waf1 were analyzed by real-time fluorescence PCR. Results Pretreatment with 10~200 mg/L of EGb761 for 3 hours reduced the sensitivity of hUC-MSCs to t-BHP ( 100 μmol/L) induced proliferation inhibition, while EGb761 over 100 mg/L had no significant effect on enhancing the protection of hUC-MSCs . EGb761 at 100 mg/L prohibited hUC-MSCs apoptosis and MDA accumulation in hUC-MSCs induced by 100μmol/L of t-BHP acting for 6 hours, maintained the enzymatic activity of SOD, and decreased the expression of p53 and p21Cip1/Waf1 in hUC-MSCs with t-BHP-induced injury. Conclusion EGb761 is capable of protecting hUC-MSCs against oxidative stress injury, and its mechanism is probably related with the modulation of p53/p21 signal pathway.%【目的】观察银杏叶提取物EGb761对叔丁基过氧化氢(t-BHP)诱导人脐带间充质干细胞(hUC-MSCs)损伤的干预作用。【方法】取原代培养的hUC-MSCs,采用四甲基偶氮唑盐(MTT)比色法检测细胞增殖,确定建立氧化应激损伤细胞模型所需的t-BHP浓度以及EGb761的最适作用浓度;采用Annexin V异硫氰酸荧光素/碘化丙啶(FITC/PI)双染流式细胞术测定100 mg/L EGb761对100μmol/L t-BHP所致hUC-MSCs凋亡的影响,同时检测脂质过氧化物丙二醛(MDA

  5. Inhibition of glutathione S-transferase P1-1 in mouse lung epithelial cells by the tumor promoter 2,6-di-tert-butyl-4-methylene-2,5-cyclohexadienone (BHT-quinone methide): protein adducts investigated by electrospray mass spectrometry.

    Science.gov (United States)

    Lemercier, Jean-Noël; Meier, Brent W; Gomez, Jose D; Thompson, John A

    2004-12-01

    Oxidation of the food preservative 2,6-di-tert-butyl-4-methylphenol (BHT) by mouse lung cytochrome P450 produces electrophilic quinone methides thought to promote lung tumors in mice by covalent binding to critical proteins. Specific pulmonary targets of 2,6-di-tert-butyl-4-methylenecyclohexa-2,5-dienone (BHT-QM) have not been identified, however. The present work was undertaken to determine if glutathione S-transferase P1-1 (GSTP1-1) is alkylated by BHT-QM, as this protein is overexpressed in tumors and has important roles in protecting cells from electrophiles and oxidants and in regulating stress kinases. This work was conducted with cell lines C10 and E10 derived from mouse lung epithelia and their spontaneous transformants, the tumorigenic cell lines A5 and E9. Cytosolic GSTs were isolated by affinity chromatography and analyzed by ESI-LC/MS. Ion current chromatograms indicated that GSTP1 predominates over the other isoforms, especially in tumorigenic cells. Treatment with BHT-QM inhibited cytosolic GST activity by 28-44%, and inhibition was exacerbated by depleting intracellular GSH. Alkylation of GSTP1 by BHT-QM was investigated by separating cytosolic proteins with two-dimensional SDS-PAGE and detecting adducts by Western blotting with polyclonal antibodies that recognize the BHT group. The identity of GSTP1 comigrating with immunoreactive material was confirmed by in-gel proteolysis and LC/MS/MS analysis. Human GSTP1 was utilized to investigate the specific residues involved in QM binding. The only peptide adduct detected in digests of monoadducted GSTP1 corresponded to Cys101, whereas adducts at Cys14, Cys47, and Cys101 were identified from the trialkylated protein. Losses of transferase activity were most influenced by alkylation at Cys47, but binding to Cys14 appeared to inhibit the activity further. These findings demonstrate that cytosolic GSTP1 may be a target for BHT-QM resulting in decreased cellular protection from electrophiles and oxidants

  6. Electrocatalytic Oxidation of H2O2 at a Carbon Paste Electrode Modified with a Nickel (Ⅱ)-5, 11,17, 23-Tetra-Tert-Butyl-25,27-Bis ( Diethylcarbamoylmethoxy ) Calix[ 4 ] Arene Complex and Its Application

    Institute of Scientific and Technical Information of China (English)

    LiChun-ya; ChertYong; WangChang-fa; LiHai-bing; ChenYuan-yin

    2003-01-01

    Electrochemical behavior of a carbon paste elec-trode (CPE) modified with nickel(Ⅱ)-5, 11, 17, 23-tetra-tert-butyl-25, 27-bis (diethylcarhamoylmethoxy) calix[4] arene (Ni(Ⅱ)-L) complex and its electrocatalytic activity towards the oxidation of hydrogen peroxide were investigated by cyclic voham-metric technique in a 5.0 × 10-2 mol/L NaClO4 + 1. 0× 10-3 mol/L NaOH solution. It was found that Ni(Ⅱ)-L acts as an effective catalyst for the oxidation of hydrogen peroxide. The modified electrode exhibited a linear response over a hydrogen peroxide concentrations in the range of 2. 0 × 10-6--1.0 × 10-4 mol/L with a detection limit as low as 1.0× 10-6 mol/L. The relative standard deviation was 3. 5% for 5 successive determi-nations of H2O2 at 1.0×10-5 mol/L. The modified electrode was used successfully in rainwater analysis.

  7. Discovery, Synthesis, And Structure-Based Optimization of a Series of N-(tert-Butyl)-2-(N-arylamido)-2-(pyridin-3-yl) Acetamides (ML188) as Potent Noncovalent Small Molecule Inhibitors of the Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV) 3CL Protease

    Energy Technology Data Exchange (ETDEWEB)

    Jacobs, Jon [Vanderbilt Univ., Nashville, TN (United States); Vanderbilt Specialized Chemistry Center for Probe Development (MLPCN), Nashville, TN (United States); Grum-Tokars, Valerie [Northwestern Univ., Chicago, IL (United States); Zhou, Ya [Vanderbilt Univ., Nashville, TN (United States); Vanderbilt Specialized Chemistry Center for Probe Development (MLPCN), Nashville, TN (United States); Turlington, Mark [Vanderbilt Univ., Nashville, TN (United States); Vanderbilt Specialized Chemistry Center for Probe Development (MLPCN), Nashville, TN (United States); Saldanha, S. Adrian [Sripps Research Inst. Molecular Screening Center, Jupiter, FL (United States); Chase, Peter [Sripps Research Inst. Molecular Screening Center, Jupiter, FL (United States); Eggler, Aimee [Purdue Univ., West Lafayette, IN (United States); Dawson, Eric S. [Vanderbilt Univ., Nashville, TN (United States); Vanderbilt Specialized Chemistry Center for Probe Development (MLPCN), Nashville, TN (United States); Baez-Santos, Yahira M. [Purdue Univ., West Lafayette, IN (United States); Tomar, Sakshi [Purdue Univ., West Lafayette, IN (United States); Mielech, Anna M. [Loyola Univ. Medical Center, Maywood, IL (United States); Baker, Susan C. [Loyola Univ. Medical Center, Maywood, IL (United States); Lindsley, Craig W. [Vanderbilt Univ., Nashville, TN (United States); Vanderbilt Specialized Chemistry Center for Probe Development (MLPCN), Nashville, TN (United States); Hodder, Peter [Sripps Research Inst. Molecular Screening Center, Jupiter, FL (United States); Mesecar, Andrew [Purdue Univ., West Lafayette, IN (United States); Stauffer, Shaun R. [Vanderbilt Univ., Nashville, TN (United States); Vanderbilt Specialized Chemistry Center for Probe Development (MLPCN), Nashville, TN (United States)

    2012-12-11

    A high-throughput screen of the NIH molecular libraries sample collection and subsequent optimization of a lead dipeptide-like series of severe acute respiratory syndrome (SARS) main protease (3CLpro) inhibitors led to the identification of probe compound ML188 (16-(R), (R)-N-(4-(tert-butyl)phenyl)-N-(2-(tert-butylamino)-2-oxo-1-(pyridin-3-yl)ethyl)furan-2-carboxamide, Pubchem CID: 46897844). But, unlike the majority of reported coronavirus 3CLpro inhibitors that act via covalent modification of the enzyme, 16-(R) is a noncovalent SARS-CoV 3CLpro inhibitor with moderate MW and good enzyme and antiviral inhibitory activity. A multicomponent Ugi reaction was utilized to rapidly explore structure–activity relationships within S1', S1, and S2enzyme binding pockets. Moreover, the X-ray structure of SARS-CoV 3CLpro bound with 16-(R) was instrumental in guiding subsequent rounds of chemistry optimization. 16-(R) provides an excellent starting point for the further design and refinement of 3CLpro inhibitors that act by a noncovalent mechanism of action.

  8. {2-[Bis(2,4-di-tert-butylphenoxyphosphanyloxy-κP]-3,5-di-tert-butylphenyl-κC1}{3,3′-di-tert-butyl-5,5′-dimethoxy-2,2′-bis[(1,1,2,2-tetraphenylethane-1,2-dioxyphosphanyloxy-κP]biphenyl}rhodium(I toluene-d8 2.7-solvate

    Directory of Open Access Journals (Sweden)

    Detlef Selent

    2016-12-01

    Full Text Available The molecule of the title compound, [Rh(C42H62O3P(C74H68O4P2]·2.7C7D8, consists of two phospharhodacyclic substructures sharing the Rh atom, which are formed by coordination/ortho-metallation of a triaryl phosphite, and by the coordination of a rigid bisphosphite, respectively. The metal displays a tetrahedrally distorted square-planar coordination geometry. A tert-butyl group shows rotational disorder over two positions with refined site occupancy of 0.561 (3:0.439 (3. Two partial-occupancy toluene solvent molecules are disordered over two orientations with site occupancies of 0.5:0.3 and 0.5:0.4, respectively. Intramolecular C—H...O hydrogen bonds are observed. In the crystal, complex molecules and toluene solvent molecules pack as alternating layers parallel to the ac plane.

  9. Syntheses of Tert-butyl Esters of 3,28-Di-o-succinyl-aminoacyl-betulin and Their Effects on the Proliferation and Apoptosis of HepG-2%桦木醇丁二酸酯氨基酸叔丁酯的合成及对肝癌细胞增殖和凋亡的影响

    Institute of Scientific and Technical Information of China (English)

    隋若君; 张小丽; 方桂珍; 付玉杰

    2013-01-01

    Tert-butyl ester of 3,28-di-o-succinyl-alanylamino-betulin(SAB) and tert-butyl ester of 3,28-di-o-succinyl-glycylamino-betulin(SGB) were synthesized from betulin. The structure of the products were identified by 1H NMR and MS. In order to study the effects of betulin derivatives on inhibiting tumor cells, using MTT assay, the SAB and SGB carried out on the HepG-2 (Human Hepatocellular carcinoma cells) activity analysis. The results showed that SAB and SGB were specific to promote their apoptosis of HepG-2. The apoptosis was time and concentration dependent. Effect after 72 h ,IC50 were 15. 33 μmol/L and 17.01 μmol/L. IC50 of SAB and SGB was significantly lower than IC50 of betulin. On HepG-2 cells, the IC50 of SAB is about 1/6 of the IC50 of betulin; The IC50 of SGB is about 1/5 of the IC50 of betulin. The results showed that SAB and SGB's anti-tumor activity was better than betulin.%以桦木醇为原料合成了桦木醇丁二酸酯甘氨酸叔丁酯(桦甘酯)和桦木醇丁二酸酯丙氨酸叔丁酯(桦丙酯),采用1H NMR和MS确证了化合物的结构.用噻唑兰(MTT)比色法,对桦甘酯和桦丙酯进行了对HepG-2(肝癌细胞)活性分析.结果表明:桦甘酯和桦丙酯对HepG-2有专一促其凋亡的作用,其凋亡作用呈时间和浓度依赖.作用72 h后,半数抑制浓度(IC50)值分别为15.33和17.01 μmol/L.桦甘酯和桦丙酯的IC50值与桦木醇的IC50值相比明显降低;对HepG-2细胞桦甘酯的IC50值约为桦木醇IC50值的1/6;桦丙酯的IC50值约为桦木醇IC50值的1/5,由此说明,桦甘酯和桦丙酯在抑制肿瘤细胞生长的活性方面明显优于桦木醇.

  10. Crystal structure of (E)-2,6-di-tert-butyl-4-{[2-(2,4-di­nitro­phen­yl)hydrazinylidene]meth­yl}phenol

    Science.gov (United States)

    Kalibabchuk, Valentina A.

    2017-01-01

    The essential part (including all the non-hydrogen atoms except two methyl carbons) of the mol­ecule of the title compound, C21H26N4O5, lies on a mirror plane, which bis­ects the t-butyl groups. The conformation of the C=N bond of this Schiff base compound is E, and there is an intra­molecular N—H⋯O hydrogen bond present, forming an S(6) ring motif. In the crystal, mol­ecules are linked via O—H⋯O hydrogen bonds, forming zigzag chains propagating along the a-axis direction. There are no other significant inter­molecular contacts present. PMID:28217318

  11. 4-tert-Butyl-3′,4′-bis(4-methylphenyl-3,4-dihydro-1H,4′H-spiro[naphthalene-2,5′-[1,2]oxazol]-1-one

    Directory of Open Access Journals (Sweden)

    Mohamed Akhazzane

    2011-07-01

    Full Text Available In the title compound, C30H31NO2, the cyclohexanone ring in the naphthalene fused-ring system adopts a half-chair conformation, presumably due to conjugation of the benzene ring. The naphthalene ring system makes dihedral angles of 86.63 (7, 65.15 (8 and 63.18 (8° with respect to the two methylbenzene planes and the 1,2-oxazole ring system. Intermolecular C—H...O and C—H...N hydrogen bonding and C—H...π interactions stabilize the crystal structure. The H atoms of the two methyl groups of the methylphenyl groups are disordered over two positions with equal occupancies.

  12. Protective effects of xanthohumol against the genotoxicity of benzo(a)pyrene (BaP), 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) and tert-butyl hydroperoxide (t-BOOH) in HepG2 human hepatoma cells.

    Science.gov (United States)

    Plazar, Janja; Zegura, Bojana; Lah, Tamara T; Filipic, Metka

    2007-08-15

    Xanthohumol is the major prenylated flavonoid present in the hop plant Humulus lupulus L. (Cannabinaceae) and a common ingredient of beer. Recently, xanthohumol has gained considerable interest due to its potential cancer chemo-preventive effect. The aim of this study was to reveal the possible anti-genotoxic activity of xanthohumol in metabolically competent human hepatoma HepG2 cells, by use of the comet assay. Xanthohumol by itself was neither cytotoxic nor genotoxic to the cells at concentrations below 10microM. However, a significant protective effect against the pro-carcinogens benzo(a)pyrene (BaP) and 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) was observed at concentrations as low as 0.01microM. In cells treated with xanthohumol in combination with tert-butyl hydroperoxide (t-BOOH) - an inducer of reactive oxygen species (ROS) - no protective effect was observed and xanthohumol also showed no significant scavenging activity against 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals. On the other hand, HepG2 cells pre-treated with xanthohumol showed significantly reduced levels of t-BOOH-induced DNA strand breaks, indicating that its protective effect is mediated by induction of cellular defence mechanisms against oxidative stress. As xanthohumol is known to be an effective inhibitor of cytochrome P450 enzymes and an inducer of NAD(P)H: quinone reductase (QR), our findings can be explained by an inhibition of metabolic activation of pro-carcinogens and/or by induction of carcinogen-detoxifying and anti-oxidative enzymes by xanthohumol. These results provide evidence that xanthohumol displays anti-genotoxic activity in metabolically competent human cells.

  13. Synthesis of novel 6-bromo-8-(tert-butyl)-5H-[1,2,4] triazino[5,6-b] indole-3-thiols%6-溴-8-叔丁基-5H-[1,2,4]三嗪并[5,6-b]吲哚-3-硫醇类化合物的合成

    Institute of Scientific and Technical Information of China (English)

    符鑫博; 白仁青卓玛; 赵勋章; 李阳

    2016-01-01

    5-叔丁基靛红(1)与N-溴代丁二酰亚胺(NBS)在环境友好的聚乙二醇-400(PEG-400)为溶剂的条件下进行溴代反应,生成5-叔丁基-7-溴靛红(2a)。随后,其在NaH为碱、DMF为溶剂的条件下发生烷基化反应,生成N-烃基取代的5-叔丁基-7-溴靛红2b-f。化合物2a-f与硫代氨基脲(3)反应得到一系列结构新颖的6-溴-8-叔丁基-5H-[1,2,4]三嗪并[5,6-b]吲哚-3-硫醇衍生物4a-f。%The synthesis of a series of structural newly 6-bromo-8-(tert-butyl)-5H-[1,2,4]triazino[5,6-b]indole-3-thiol deriva-tives 4a-f had been achieved via the condensation reaction of 7-bromo-5-tert-butylisatins 2a-f with thiosemicarbazide(3). The sub-strate 2a was prepared through the bromination reaction of 5-tert-butylisatin(1)with N-bromosuccinimide(NBS)using eco-friendly PEG-400 as solvent,which was further alkylated in DMF in the presence of NaH to give the corresponding substrates 2b-f.

  14. 用 Avrami-Ozawa 模型研究6-叔丁基间甲酚非等温结晶动力学%Kinetics Study on Nonisothermal Crystallization of 6-tert-Butyl-3-methylphenol by Avrami-Ozawa Model

    Institute of Scientific and Technical Information of China (English)

    李智勇; 赵胤; 孙艳红; 陈燕鑫; 尹秋响; 陈巍

    2012-01-01

    In this paper, the kinetic behavior of the static melt crystallization of 6-tert-butyl-3-methyIphe-nol (3M6TB) was investigated by DSC at different cooling rates. The relationship between relative crys-tallinity and temperature at different cooling rates was determined. The experimental data was fitted with Avrami-Ozawa model and kinetic parameters such as FT and θ were obtained. Both parameters increased with cooling rate so that the relative crystallinity of 3M6TB showed similar temperature dependence with them.%主要研究了6-叔丁基间甲酚(3M6TB)的静态熔融结晶动力学.通过差示扫描量热仪(DSC)在不同的降温速率下测定降温结晶过程中的放热曲线,然后对数据进行分析得到相对转化度随温度变化的关系.用Avrami-Ozawa模型处理试验数据得到3M6TB静态熔融结晶过程的力学参数FT(达到给定结晶度所需要的冷却速率的值)以及θ(Avrami常数对Ozawa常数的比值),FT和θ均随着降温速率的增大而增大,导致在本研究试验条件下一定结晶时间内3M6TB的相对结晶度随降温速率的增加而提高.

  15. Studies on the separation of {sup 89}Sr(II) from irradiated yttria target using 4, 4{sup '}(5{sup '}) di-tert-butyl-cyclohexano-18-crown-6 (DtBuCH18C6) by solvent extraction technique

    Energy Technology Data Exchange (ETDEWEB)

    Saha, Debasish; Vithya, Jayagopal; Kumar, Ramalingam; Venkata Subramani, Canchipuram Ramamoorthy; Vasudeva Rao, Polur Ranga [Indira Gandhi Centre for Atomic Research (IGCAR), Kalpakkam (India). Chemistry Group

    2016-07-01

    The radioisotope {sup 89}Sr as {sup 89}SrCl{sub 2} is medically useful for bone pain palliation and is produced in fast reactors using the {sup 89}Y(n, p){sup 89}Sr reaction. A procedure for isolation of the radionuclide {sup 89}Sr by chemical processing of the irradiated Y{sub 2}O{sub 3} target has been standardised and trial runs have been carried out at the Fast Breeder Test Reactor (FBTR), Kalpakkam. The chemical processing of the irradiated Y{sub 2}O{sub 3} target involves (i) the removal of target Y(III) by TBP extraction and (ii) further purification of the separated {sup 89}Sr fraction by cationic exchange chromatography. However a selective isolation of {sup 89}Sr by the Sr-specific crown ether makes the above chemical processing faster and relatively simple. This work presents a study on the selective removal of Sr from the irradiated target dissolver solution using the Sr-specific crown ether 4,4{sup '}(5{sup '}) di-tert-butyl-cyclohexano-18-crown-6 (DtBuCH18C6) in octanol medium. The separation behaviour of the other impurities such as Ce(IV), Y(III), Tb(III), Eu(III), Zn(II), Mn(II) and Rb(I) present along with Sr(II) in the irradiated sample was also investigated. The method of separation by using the crown ether DtBuCH18C6 is proved to be a potential tool for the purification of {sup 89}Sr(II) source produced from yttria target in fast reactors.

  16. Simulación del Proceso de Producción del Éter Etil Tert-Butílico (ETBE: Influencia de la Relación Etanol/Isobuteno Simulation of Production Process for Ethyl Tert-Butyl Ether (ETBE: Influence of the Ethanol/Isobutene Ratio

    Directory of Open Access Journals (Sweden)

    P.A. Dávila

    2004-01-01

    Full Text Available Este trabajo describe una metodología que combina el diseño conceptual y la simulación de procesos para determinar la influencia de la relación molar de alimentación etano/isobuteno sobre la selectividad hacia éter etil tert-butílico. El diseño conceptual de la columna de destilación se basó en un método gráfico de curvas de residuo y permitió determinar los esquemas de separación factibles y maximizar la concentración de éter en los productos de fondo de la columna de destilación. La simulación del proceso permitió determinar las condiciones de operación y los parámetros de diseño de los reactores y de la columna de destilación. Se concluye que la metodología disminuye drásticamente el tiempo necesario para obtener resultados con un simulador de procesosThis work describes a methodology which combines conceptual design and process simulation to determine the influence of the molar feed ratio of ethanol/isobutene on tert-butyl ethyl ether selectivity. The conceptual design of distillation columns was based on the residue curve map and it allowed determination of feasible separation schemes and maximization of the concentration of ether in the stream bottom of the distillation column. Simulation of the process has allowed determining the operating variables and design parameters for the reactors and the distillation column. It is concluded that this methodology significantly reduces the time required to obtain results with a process simulator

  17. STUDIES ON RADICAL POLYMERIZATION OF METHYL METHACRYLATE INITIATED WITH ORGANIC PEROXIDE-AMINE SYSTEMS

    Institute of Scientific and Technical Information of China (English)

    QIU Kunyuan; SHUI Li; FENG Xinde

    1984-01-01

    Radical polymerization of methyl methacrylate (MMA) initiated with various diacyl peroxideamine systems was studied. Benzoyl peroxide (BPO) and lauroyl peroxide (LPO) were used as diacyl peroxide component, N,N-dimethyl aniline (DMA) and its para substituted derivatives, i.e., N,N-dimethyl-p-toluidine (DMT), p-hydroxymethyl-N,N-dimethyl aniline (HDMA), p-nitro-N,N-dimethyl aniline (NDMA) and p-dimethylamino benzaldehyde (DMAB) were used as amine components. It was found that the peroxide-DMT systems give higher rates of bulk polymerization Rp of MMA than the organic hydroperoxide-DMT systems with the following descending order BPO-DMT>LPO-DMT>CHP (cumene hydroperoxide)-DMT>TBH (tert-butyl hydroperoxide)-DMT.The aromatic tertiary amines possess obvious structural effect on the Rp values in the diacyl peroxideamine system. The overall activation energy of MMA polymerization was determined and the kinetics of polymerization of MMA initiated with BPO-DMT system was investigated.

  18. Production d'isobutène de haute pureté par décomposition du MTBE High-Purity Isobutene Production from Mtbe

    Directory of Open Access Journals (Sweden)

    Meunier P. B.

    2006-11-01

    Full Text Available La décomposition du MTBE en isobutène et méthanol s'accompagne de réactions secondaires (oligomérisation de l'isobutène, hydratation de l'isobutène, déshydratation du méthanol. Les différents types de catalyseurs utilisés, les mécanismes et les cinétiques suggérés, ainsi que les sites actifs et les espèces adsorbées proposés dans la littérature sont examinés dans le cas de la réaction principale, et des réactions secondaires. La formulation du catalyseur et la nature des sites actifs (Brönsted, Lewis ont une incidence particulière sur la réaction. Les données de la littérature portent essentiellement sur des catalyseurs de type résines présentant une acidité de Brönsted. Sur catalyseurs de type oxydes il apparaît que les sites acides de Lewis, catalysent la réaction principale, tandis que les réactions secondaires sont essentiellement dues à la présence d'acidité de Brönsted. Un contrôle de l'acidité des formulations catalytiques est nécessaire afin de minimiser les réactions secondaires, et de produire de l'isobutène très pur. Under suitable conditions, methyl-tert-butyl ether (MTBE is decomposed into isobutene (C4H8 and methanol (CH3OH. This decomposition is a reversible endothermic chemical reaction ((*** = 15. 6 kcal/mol in the gas phase. When this reaction is situated downstream from MTBE synthesis from a C4 cut, this results in the separation of the different isomers in this cut by a less costly method than the one now used, which consists of concentrated sulfuric-acid extraction. The isobutene obtained by MTBE decomposition is very pure and meets the specifications required for subsequent polymerization into butyl rubber or methyl methacrylate. The MTBE decomposition reaction is accompanied by secondary reactions such as the oligomerization of isobutene (mainly the formation of dimers, the dehydration of methanol into dimethylether, and the hydration of isobutene into tert-butyl alcohol. MTBE

  19. Determination of the extractive capacity of para-tert butyl calix[8]arene octa-phosphinoylated towards uranyl ions from an aqueous-acidic-salty medium; Determinacion de la capacidad extractiva del p-ter-butilocalix[8]areno octa-fosfinoilado hacia iones uranilo de un medio acuo-acido salino

    Energy Technology Data Exchange (ETDEWEB)

    Serrano V, E. C.

    2011-07-01

    The extraction properties of octa-phosphinoylated para-tert butyl calix[8]arene (prepared in the laboratory) in chloroform towards uranyl ions from an aqueous-acidic-salty medium (HNO{sub 3}-3.5 NaNO{sub 3}) containing uranyl nitrate salt, was investigated. Two spectroscopic techniques UV/Vis and Luminescence were used for this study. The latter permitted analyze the fluorescence from the uranyl ions influenced by the surrounding medium. Both permitted to learn about the power of this calixarene as extractant towards the mentioned ions. Its extraction ability or capability using this calixarene at 5.91 x 10{sup -4} M towards the uranyl ions was 400% as determined by UV/Vis while fluorescence revealed 100% of uranyl ion extraction. A closed analysis of the results obtained by using these techniques revealed that the stoichiometry of the main extracted species was 1calixarene:2 uranyl ions. The loading capacity of the calixarene ligand towards the uranyl ions was also investigated using both techniques. UV/Vis resulted to be inadequate for quantifying exactly the loading capacity of the calixarene whereas luminescence was excellent indeed, using a 5.91 x 10{sup -4} M calixarene concentration, its loading capacity was 0.157 M of free uranyl ions from 0.161 M of uranyl ions present in the aqueous-acidic-salty medium. The extracts from the ability and capacity studies were concentrated to dryness, purified and the dried extracts were analyzed by infrared and neutron activation analysis. By these techniques it was demonstrated that during the extraction of the uranyl ions by the calixarene ligand they form thermodynamically and kinetically stable complexes, since in the solid state, the 1:2, calixarene; uranyl ions stoichiometry was kept with the minimum formula: (UO{sub 2}){sub 2}B{sub 8}bL{sup 8}(NO{sub 3}){sub 4}(H{sub 2}O){sub 4}CHCl{sub 3}(CH{sub 3}OH){sub 3} the methanol molecules come from its purification. It is proposed that B{sub 8}bL{sup 8} calixarene in

  20. The chemical behavior of terminally tert-butylated polyolefins.

    Science.gov (United States)

    Klein, Dagmar; Hopf, Henning; Jones, Peter G; Dix, Ina; Hänel, Ralf

    2015-01-01

    The chemical behavior of various oligoenes 2 has been studied. The catalytic hydrogenation of diene 3 yielded monoene 4. Triene 7 was hydrogenated to diene 8, monoene 9 and saturated hydrocarbon 10. Bromine addition to 3 and 7 yielded the dibromides 17 and 18, respectively, i.e., the oligoene system has been attacked at its terminal olefinic carbon atoms. Analogously, the higher vinylogs 19 and 20 yielded the 1,8- and 1,10-bromine adduts 23 and 24, respectively, when less than 1 equivalent of bromine was employed. Treatment of tetraene 19 with excess bromine provided tetrabromide 25. In epoxidation reactions, both with meta-chloroperbenzoic acid (MCPBA) and dimethyldioxirane (DMDO) two model oligoenes were studied: triene 7 and tetraene 19. Whereas 7 furnished the rearrangement product 31 with MCPBA, it yielded the symmetrical epoxide 32 with DMDO. Analogously, 19 was converted to mono-epoxide 33 with MCPBA and to 34 with DMDO. Diels-Alder addition of 7 with N-phenyltriazolinedione (PTAD) did not take place. Extension of the conjugated π-system to the next higher vinylog, 19, caused NPTD-addition to the symmetrical adduct 37 in good yield. Comparable results were observed on adding NPTD (equivalent amount) to pentaene 20 and hexaene 21. Using 36 in excess provided the 2:1-adduct 40 from 21 and led to a complex mixture of adducts from heptaene 22. With tetracyanoethylene (TCNE) as the dienophile, tetraolefin 19 yielded the symmetrical adduct 43, although the reaction temperature had to be increased. Pentaene 20 and hexaene 21 led to corresponding results, adducts 44 and 45 being produced in acceptable yields. With nonaene 42 and TCNE the 2:1-adduct 48 was generated according to its spectroscopic data. Exploratory photochemical studies were carried out with tetraene 19 as the model compound. On irradiation this reacted with oxygen to the stable endo-peroxide 52.

  1. The chemical behavior of terminally tert-butylated polyolefins

    Directory of Open Access Journals (Sweden)

    Dagmar Klein

    2015-07-01

    Full Text Available The chemical behavior of various oligoenes 2 has been studied. The catalytic hydrogenation of diene 3 yielded monoene 4. Triene 7 was hydrogenated to diene 8, monoene 9 and saturated hydrocarbon 10. Bromine addition to 3 and 7 yielded the dibromides 17 and 18, respectively, i.e., the oligoene system has been attacked at its terminal olefinic carbon atoms. Analogously, the higher vinylogs 19 and 20 yielded the 1,8- and 1,10-bromine adduts 23 and 24, respectively, when less than 1 equivalent of bromine was employed. Treatment of tetraene 19 with excess bromine provided tetrabromide 25. In epoxidation reactions, both with meta-chloroperbenzoic acid (MCPBA and dimethyldioxirane (DMDO two model oligoenes were studied: triene 7 and tetraene 19. Whereas 7 furnished the rearrangement product 31 with MCPBA, it yielded the symmetrical epoxide 32 with DMDO. Analogously, 19 was converted to mono-epoxide 33 with MCPBA and to 34 with DMDO. Diels–Alder addition of 7 with N-phenyltriazolinedione (PTAD did not take place. Extension of the conjugated π-system to the next higher vinylog, 19, caused NPTD-addition to the symmetrical adduct 37 in good yield. Comparable results were observed on adding NPTD (equivalent amount to pentaene 20 and hexaene 21. Using 36 in excess provided the 2:1-adduct 40 from 21 and led to a complex mixture of adducts from heptaene 22. With tetracyanoethylene (TCNE as the dienophile, tetraolefin 19 yielded the symmetrical adduct 43, although the reaction temperature had to be increased. Pentaene 20 and hexaene 21 led to corresponding results, adducts 44 and 45 being produced in acceptable yields. With nonaene 42 and TCNE the 2:1-adduct 48 was generated according to its spectroscopic data. Exploratory photochemical studies were carried out with tetraene 19 as the model compound. On irradiation this reacted with oxygen to the stable endo-peroxide 52.

  2. 5-tert-Butyl-2-hydroxy-3-(2-thienylbenzaldehyde

    Directory of Open Access Journals (Sweden)

    Yanwei Wang

    2010-09-01

    Full Text Available In the crystal structure of the title compound, C15H16O2S, the thiophene ring is essentially planar (r.m.s. deviation = 0.006 Å for all non-H atoms and roughly coplanar with the benzene ring, the dihedral angle between the mean planes of the rings being 4.35 (8°. An intramolecular O—H...O hydrogen bond is observed between the OH group and the aldehyde O atom.

  3. Diaqua[μ-11,23-di-tert-butyl-3,7,15,19-tetraazatricyclo[19.3.1.19,13]tetracosa-1(25,2,6,9,11,13(26,14,19,21,23-dodecaene-25,26-diolato-κ4N3,N7,O25,O26:κ4N15,N19,O25,O26]dicopper(II bis(perchlorate

    Directory of Open Access Journals (Sweden)

    Qiang Xu

    2012-08-01

    Full Text Available In the dinuclear title complex, [Cu2(C30H38N4O2(H2O2](ClO42, the coordination cation has crystallographically imposed twofold rotational symmetry. The CuII ion is five-coordinated by two N and two O atoms from the macrocylic ligand and one O atom from a water molecule, forming a square-pyramidal N2O3 geometry with the water molecule in the apical position. The distance between the two CuII atoms is 3.0930 (5 Å. Hydrogen bonds between water molecules and between water molecules and perchlorate anions assemble two cations and four anions into discrete supermolecules of S4 symmetry. Intramolecular O—H...N hydrogen bonds are also observed. The perchlorate anion and the tert-butyl group are disordered over two positions, with occupancies of the major positions of 0.527 (11 and 0.592 (9, respectively.

  4. Synthesis, characterization and computational studies of (E)-2-{[(2-aminopyridine-3-yl)imino]-methyl}-4,6-di-tert-butylphenol

    Energy Technology Data Exchange (ETDEWEB)

    Carreno, Alexander; Vega, Andres, E-mail: ichavez@uc.cl [Departamento de Ciencias Quimicas, Facultad de Ciencias Exactas, Universidad Andres Bello, Santiago (Chile); Zarate, Ximena; Schott, Eduardo [Lab. Bionanotecnologia, Departamento de Ciencias Quimico-Biologicas, Universidad Bernardo O' Higgins, Santiago (Chile); Gacitua, Manuel; Valenzuela, Ninnette; Manriquez, Juan M.; Chavez, Ivonne [Departamento de Quimica Inorganica, Facultad de Quimica, Pontificia Universidad Catolica de Chile, Santiago (Chile); Preite, Marcelo [Departamento de Quimica Inorganica, Facultad de Quimica, Pontificia Universidad Catolica de Chile, Santiago (Chile)

    2014-07-01

    (E)-2-{[(2-Aminopyridine-3-yl)imino]-methyl}-4,6-di-tert-butyl-phenol ( 3: ), a ligand containing an intramolecular hydrogen bond, was prepared according to a previous literature report, with modifications, and was characterized by UV-vis, FTIR, {sup 1}H-NMR, {sup 13}C-NMR, HHCOSY, TOCSY and cyclic voltammetry. Computational analyses at the level of DFT and TD-DFT were performed to study its electronic and molecular structures. The results of these analyses elucidated the behaviors of the UV-vis and electrochemical data. Analysis of the transitions in the computed spectrum showed that the most important band is primarily composed of a HOMO→LUMO transition, designated as an intraligand (IL) charge transfer. (author)

  5. Effect of cytochalasin B on 3-O-[(14)C]-methyl-D-glucose or D-[U-(14)C]glucose handling by BRIN-BD11 cells.

    Science.gov (United States)

    Cetik, Sibel; Rzajeva, Aigun; Malaisse, Willy J; Sener, Abdullah

    2014-07-01

    The present study aimed to investigate the effects of cytochalasin B (20 μM) on the uptake of 3-O-[(14)C]-methyl-D-glucose or D-[U-(14)C]glucose (8.3 mM each) by BRIN-BD11 cells. Taking into account the distribution space of tritiated water ((3)HOH), which was unexpectedly increased shortly after exposure of the cells to cytochalasin B and then progressively returned to its control values, and that of L-[1-(14)C]glucose, used as an extracellular marker, it was demonstrated that cytochalasin B caused a modest, but significant inhibition of the uptake of D-glucose and its non-metabolized analog by the BRIN-BD11 cells. These findings resemble those observed in acinar or ductal cells of the rat submaxillary gland and displayed a relative magnitude comparable to that found for the inhibition of D-glucose metabolism by cytochalasin B in purified pancreatic islet B cells. These findings reinforce the view that the primary site of action of cytochalasin B is located at the level of the plasma membrane.

  6. ATRA inhibits the proliferation of DU145 prostate cancer cells through reducing the methylation level of HOXB13 gene.

    Directory of Open Access Journals (Sweden)

    Zhiwei Liu

    Full Text Available All-trans retinoic acid (ATRA has been widely investigated for treatments of many cancers including prostate cancer. HOXB13, silenced in androgen receptor-negative (AR(- prostate cancer cells, plays a role in AR(- prostate cancer cell growth arrest. In this study we intended to elucidate the mechanisms that are involved in the proliferation inhibition of AR(- prostate cancer cells triggered by ATRA. We discovered that ATRA was able to induce the growth arrest and to increase HOXB13 expression in AR(- prostate cancer cells. Both EZH2 and DNMT3b participated in the repression of HOXB13 expression through an epigenetic mechanism involving DNA and histone methylation modifications. Specifically, EZH2 recruited DNMT3b to HOXB13 promoter to form a repression complex. Moreover, ATRA could upregulate HOXB13 through decreasing EZH2 and DNMT3b expressions and reducing their interactions with the HOXB13 promoter. Concurrently, the methylation level of the HOXB13 promoter was reduced upon the treatment of ATRA. Results from this study implicated a novel effect of ATRA in inhibition of the growth of AR(- resistant human prostate cancer cells through alteration of HOXB13 expression as a result of epigenetic modifications.

  7. Crystal structure of (2,4-di-tert-butyl-6-{[(6,6′-dimethyl-2′-oxido-1,1′-biphenyl-2-ylimino]methyl}phenolato-κ3O,N,O′bis(propan-2-olato-κOtitanium(IV

    Directory of Open Access Journals (Sweden)

    Liang Chen

    2014-09-01

    Full Text Available In the mononuclear TiIV title complex, [Ti(C29H33NO2(C3H6O2], the TiNO4 coordination polyhedron comprises an N-atom and two O-atom donors from the dianionic Schiff base ligand and two O-atom donors from monodentate isopropoxide anions. The stereochemistry is distorted trigonal–bipyramidal with the N-donor in an elongated axial site [Ti—N = 2.2540 (17 Å], the O-donors having normal Ti—O bond lengths [1.7937 (14 Å (axial–1.8690 (14 Å]. In the crystal, C—H...π interactions link molecules into centrosymmetric dimers.

  8. Discovery of N-(3-(5-((3-acrylamido-4-(morpholine-4-carbonyl)phenyl)amino)-1-methyl-6-oxo-1,6-dihydropyridin-3-yl)-2-methylphenyl)-4-(tert-butyl)benzamide (CHMFL-BTK-01) as a highly selective irreversible Bruton's tyrosine kinase (BTK) inhibitor.

    Science.gov (United States)

    Liang, Qianmao; Chen, Yongfei; Yu, Kailin; Chen, Cheng; Zhang, Shouxiang; Wang, Aoli; Wang, Wei; Wu, Hong; Liu, Xiaochuan; Wang, Beilei; Wang, Li; Hu, Zhenquan; Wang, Wenchao; Ren, Tao; Zhang, Shanchun; Liu, Qingsong; Yun, Cai-Hong; Liu, Jing

    2017-05-05

    Currently there are several irreversible BTK inhibitors targeting Cys481 residue under preclinical or clinical development. However, most of these inhibitors also targeted other kinases such as BMX, JAK3, and EGFR that bear the highly similar active cysteine residues. Through a structure-based drug design approach, we discovered a highly potent (IC50: 7 nM) irreversible BTK inhibitor compound 9 (CHMFL-BTK-01), which displayed a high selectivity profile in KINOMEscan (S score (35) = 0.00) among 468 kinases/mutants at the concentration of 1 μM. Compound 9 completely abolished BMX, JAK3 and EGFR's activity. Both X-ray crystal structure and cysteine-serine mutation mediated rescue experiment confirmed 9's irreversible binding mode. 9 also potently inhibited BTK Y223 auto-phosphorylation (EC50: <30 nM), arrested cell cycle in G0/G1 phase and induced apoptosis in U2932 and Pfeiffer cells. We believe these features would make 9 a good pharmacological tool to study the BTK related pathology. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  9. 复方血栓通对人视网膜血管内皮细胞抗氧化损伤的保护作用及其机制%Protective effects and mechanism of fufang xueshuantong on tert-butyl hydroperoxide-induced injury of human retinal vascular endothelial cells

    Institute of Scientific and Technical Information of China (English)

    陈晓云; 李建桥; 朱晓波; 肖伟; 黄娟; 李涛; 唐仕波; 罗燕

    2011-01-01

    Background Oxidative damage may cause the functional dysfunction and death of retinal vascular endothelial cells(RVECs),and further leads to the development of retinal vascular diseases.Fufang xueshuantong has a therapeutic effect on retinal vascular diseases,but little is known about its molecular mechanism.Objective The goal of this study was to investigate the protective effects and mechanism of fufang xueshuantong on injury of human RVECs induced by tert-butyl hydroperoxide(t-BHP).Methods Human RVECs were isolated from healthy donor eyes and primarily cultured and then identified by flow cytometry.The third to fifth generations of cells were used in this experiments.The fufang xueshuantong solution of 0.0625,0.1250,0.2500,0.5000 and 1.0000 g/L were added in the cuhure plate with 5 × 104/L cells respectively in the experimental groups,and t-BHP of 75,100,200 and 300 μ.mol/L were added in the model control groups.MTT was used to detect the A490and survival rate of RVECs.The apoptotic rate and death rate of the cells were evaluated by double staining of Annexin V-FITC/PI.Morphology of human RVECs were examined using invert microscopy and Hoechst33258 staining.The expressions of nitro tyrosine (a marker of oxidative damage of protein)and 8-OHdG(a marker of oxidative damage of DNA)in human RVECs were assessed by the immunofluorescence staining.Western blot was used to detect the expressions of nuclear factorkappa B(NF-KB),p53,bcl-2 and bax after 6,12,24 hours t-BHP action.This study was approved by the Ethic Committee of Zhongshan Ophthalmic Center.Results No significant difference was found in A490value among the normal control group,0.0625,0.1250,0.2500,0.5000 and 1.0000 g/L fufang xueshuantong groups(F =1.989,P>0.05).The survival rates of the cells were lower in 75,100,200 and 300 μmol/L t-BHP groups compared with corresponding fufang xueshuantong groups(t =14.57,13.82,21.51,32.64,P< 0.01).The percentages of normal cells were evidently lower in 75

  10. ETUDE CINETIQUE DE L’ADSORPTION D’UN COLORANT CATIONIQUE (VERT DE METHYLE SUR DU CHARBON ACTIF EN MILIEU AQUEUX

    Directory of Open Access Journals (Sweden)

    O BAGHRICHE

    2008-06-01

    substrat, ont permis de constater une amélioration sensible de la capacité et de la vitesse d’adsorption du vert de méthyle sur ce support. Par ailleurs, l’adsorption de ce composé est bien décrit par les modèles cinétiques de Langmuir et Freundlich.

  11. Identification of a fragment-like small molecule ligand for the methyl-lysine binding protein, 53BP1.

    Science.gov (United States)

    Perfetti, Michael T; Baughman, Brandi M; Dickson, Bradley M; Mu, Yunxiang; Cui, Gaofeng; Mader, Pavel; Dong, Aiping; Norris, Jacqueline L; Rothbart, Scott B; Strahl, Brian D; Brown, Peter J; Janzen, William P; Arrowsmith, Cheryl H; Mer, Georges; McBride, Kevin M; James, Lindsey I; Frye, Stephen V

    2015-04-17

    Improving our understanding of the role of chromatin regulators in the initiation, development, and suppression of cancer and other devastating diseases is critical, as they are integral players in regulating DNA integrity and gene expression. Developing small molecule inhibitors for this target class with cellular activity is a crucial step toward elucidating their specific functions. We specifically targeted the DNA damage response protein, 53BP1, which uses its tandem tudor domain to recognize histone H4 dimethylated on lysine 20 (H4K20me2), a modification related to double-strand DNA breaks. Through a cross-screening approach, we identified UNC2170 (1) as a micromolar ligand of 53BP1, which demonstrates at least 17-fold selectivity for 53BP1 as compared to other methyl-lysine (Kme) binding proteins tested. Structural studies revealed that the tert-butyl amine of UNC2170 anchors the compound in the methyl-lysine (Kme) binding pocket of 53BP1, making it competitive with endogenous Kme substrates. X-ray crystallography also demonstrated that UNC2170 binds at the interface of two tudor domains of a 53BP1 dimer. Importantly, this compound functions as a 53BP1 antagonist in cellular lysates and shows cellular activity by suppressing class switch recombination, a process which requires a functional 53BP1 tudor domain. These results demonstrate that UNC2170 is a functionally active, fragment-like ligand for 53BP1.

  12. Environmental chamber study of the photochemical reaction of ethyl methyl sulfide and NOx

    Institute of Scientific and Technical Information of China (English)

    WANG Kun; DU Lin; GE Maofa

    2009-01-01

    A series of experiments were conducted in a self-made smog chamber at 300 ± 1 K and 1.01×105 Pa to simulate the photochemical reaction of ethyl methyl sulfide (EMS) and NOx. The results show that the higher the initial concentration of EMS, the more ozone is generated in the simulative reactions. It is found that the light intensity plays a very important role in the evaluation of ozone formation potential for EMS. The parameters of d(O3-NO) and IR (incremental reactivity) were used to quantify the potential of EMS on ozone formation. The obtained maximum IR values in this paper for the five simulative reactions were 1.55×10-2, 0.99×10-2, 1.36×10-2, 2.47×10-2, and 1.65×10-2, respectively. Comparison between the results we obtained here and the results we obtained before for di-tert-butyl peroxide and acetylene was made and it showed that the potential reactivity of EMS on ozone formation is at a relatively low level.

  13. Characteristics of Oxidative Storage Stability of Canola Fatty Acid Methyl Ester Stabilised with Antioxidants

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    Tirto Prakoso

    2012-11-01

    Full Text Available The storage effects on the oxidation characteristics of fatty acid methyl ester of canola oil (CME were investigated in this study. CME stabilised with two antioxidants, i.e. 2,6-di-tert-bytyl-p-cresol (BHT and 6,6-di-tert-butyl-2, 2’-methylendi-p-cresol (BPH, was stored at 20, 40 and 60°C. The oxidation stability data were measured by the Rancimat test method and it was found that both BHT and BPH addition increased the oxidation resistance of the CME. The results showed that when BPH or BHT was added at a concentration of 100 ppm, the oxidation induction period of the neat CME samples increased from 5.53 h to 6.93 h and 6.14 h, respectively. Comparing both antioxidants, BPH proved to be more effective in increasing the oxidation resistance when both antioxidants were added at the same concentration. Furthermore, the oxidation induction time decreased linearly with the storage time. It was shown that the oxidation occurred rapidly in the first 8 weeks of storage. Later, a kinetic study was undertaken and first-order kinetics were applied to explain the oxidation characteristics of the CME added with antioxidants. This kinetic study focused on exploiting the activation energy values obtained from the Arrhenius equations. Also, the oxidation effects on other quality parameters, including acid value, peroxide value, kinematic viscosity, and water content, were examined.

  14. Excess Molar Volumes and Densities for Methyl Tert- buty Ether- benzene and Methyl Tert- butyl Ether- methylcyclohexane from 293 K to 313K%甲基叔丁基醚-苯、甲基叔丁基醚-甲基环己烷二元系在293~313K温度范围的密度和过剩摩尔体积

    Institute of Scientific and Technical Information of China (English)

    龚良发; 李汝雄

    2001-01-01

    用液体比重天平测定了甲基叔丁基醚(MTBE)-苯二元系、甲基叔丁基醚-甲基环己烷二元系在293.15~313.15K下的密度值,求得过剩摩尔体积VEm.对MTBE-苯二元系,所测定的VEm都是负值,且随着温度升高,VEm的绝对值稍有增加;而对MTBE-甲基环己烷二元系,所测定的VEm都是正值,且随温度升高,VEm的值稍有增加.实验数据用Redlich-kister方程关联,用非线性回归方法求得参数.

  15. Photoredox radical conjugate addition of dithiane-2-carboxylate promoted by an iridium(iii) phenyl-tetrazole complex: a formal radical methylation of Michael acceptors.

    Science.gov (United States)

    Gualandi, Andrea; Matteucci, Elia; Monti, Filippo; Baschieri, Andrea; Armaroli, Nicola; Sambri, Letizia; Cozzi, Pier Giorgio

    2017-02-01

    A readily accessible iridium(iii) phenyl-tetrazole complex ([Ir(ptrz)2(tBu-bpy)](+), 2; Hptrz = 2-methyl-5-phenyl-tetrazole; tBu-bpy = 4,4'-di-tert-butyl-2,2'-bipyridine) is shown to be a versatile catalyst for a new photocatalytic Michael reaction. Under light irradiation in the presence of 2, a dithiane 2-carboxylic acid, obtained by simple hydrolysis of a commercially available ethyl ester, generates a 1,3-dithiane radical capable of performing addition to a variety of Michael acceptors (e.g., unsaturated ketones, esters, amides and malonates). This broad scope reaction with high yields is a formal photo-redox addition of the elusive methyl radical and the adducts obtained can be starting materials for a variety of functionalized products. The excited-state oxidation potential of catalyst 2 allows selective formation of radicals only from α-heterosubstituted carboxylates. Chemical modification of this metal complex can tune the electrochemical properties, opening a route to new highly selective catalytic photo-oxidation reactions.

  16. Pro tective Effect of Glycyrrhiza glabra Extract against tert-butyl hydroperoxide (t-BHP)-induced Hepatotoxicity in Primary Cultured Hepatocytes of Jian Carp(Cyprinus carpio var.jian)%甘草提取物对叔丁基氢过氧化物(t-BHP)诱导的建鲤原代培养肝细胞损伤的保护作用

    Institute of Scientific and Technical Information of China (English)

    曹丽萍; 贾睿; 杜金梁; 丁炜东; 殷国俊

    2012-01-01

    treatment of this disease.The present study aimed to develop an in vitro model of hepatotoxicity using tert-butyl hydroperoxide (t-BHP) as hepatotoxicant and evaluate the protective effects of Glycyrrhiza glabra extract against t-BHP induced hepatotoxicity in Jian carp (Cyprinus carpio var.jian).Exposure of the hepatocytes to 1 mmol/L t-BHP for 2 h significantly elevated the levels of glutamate oxalate transaminase (GOT),glutamate pyruvate transaminase (GPT),lactate dehydrogenase (LDH) and malondialdehyde (MDA),and reduced the cell viability and the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px).Three concentrations of G.glabra extract (0.1,0.2 and 0.4 mg/mL) were added to the primary hepatocytes before (pre-treatment),after (post-treatment) and both before and after (pre-and post-treatment)the exposure of the hepatocytes to t-BHP.Results showed that pre-and post-treatment of the hepatocytes with G.glabra extract at 0.1,0.2 and 0.4 mg/mL suppressed the elevations of LDH,GOT,GPT and MDA,and reversed the reduced activities of GSH-Px and SOD.Pre-treatment of the hepatocytes with 0.4 mg/mL G.glabra extract reduced the increased levels of GPT,GOT,LDH and MDA,and increased the reduced GSH-Px activity.Post-treatment didn't show significant effects expect for the enhanced GSH-Px activity in the cells post-treated with 0.4 mg/mL G.glabra extract.The significantly increased cell viabilities were observed when the cells were pre-treated,post-treated and pre-and post-treated with 0.2 mg/mL and 0.4 mg/mL G.glabra extract.The results also showed that the timing of G.glabra extract treatment substantially influenced the protective efficacy of the extract,the pre-and post-treatment of the hepatocytes with G.glabra extract was better than that of the other two treatment regimes.It can be concluded that G.glabra extract exhibited protective effect against t-BHP-induced hepatotoxicity in fish.Further in vivo studies are needed to provide more evidence for using G

  17. Du fratinoj

    Institute of Scientific and Technical Information of China (English)

    1996-01-01

    Vivis iam du fratinoj-Aje kaj Fatme.Iliapatrino estis duon-patrino por Fatme kaj in neamis.Foje i diris al sia edzo:-Faru kion ajn,sed mi ne plu volas vidiFatme.La sekvan tagon la patro forkondukis la

  18. Di-tert-butyl N-[2,6-bis(methoxymethoxyphenyl]iminodiacetate

    Directory of Open Access Journals (Sweden)

    Ben Capuano

    2009-04-01

    Full Text Available The title molecule, C20H31NO8, has pseudo-C2 symmetry about the C—N bond, with the bis(tert-butoxycarbonylamino group twisted from the benzene ring plane by ca 60° and the bulky tert-butoxycarbonyl (Boc groups are orientated away from the substituted aniline group. As part of an antibacterial drug discovery programme furnishing analogues of platensimycin, we unexpectedly synthesized the bis-Boc-protected aniline.

  19. N-(Fluoren-9-ylmethoxycarbonyl-l-aspartic acid 4-tert-butyl ester

    Directory of Open Access Journals (Sweden)

    Kazuhiko Yamada

    2009-11-01

    Full Text Available The bond distances and bond angles of the title compound, C23H25NO6, are consistent with values typically found for fluoren-9-ylmethoxycarbonyl-protected amino acids. The conformations of the backbone and the side chain are slightly different from those of l-aspartic acid. The crystal structure exhibits two intermolecular hydrogen bonds, forming a two-dimensional sheet structure parallel to the ab plane.

  20. Crystal structure of 2,4-di-tert-butyl-6-(hydroxymethylphenol

    Directory of Open Access Journals (Sweden)

    Ane I. Aranburu Leiva

    2016-11-01

    Full Text Available The title compound, C15H24O2, is an example of a phenol-based pendant-arm precursor. In the molecule, the phenol hydroxy group participates in an intramolecular O—H...O hydrogen bond with the pendant alcohol group, forming an S(6 ring. This ring adopts a half-chair conformation. In the crystal, O—H...O hydrogen bonds connect molecules related by the 31 screw axes, forming chains along the c axis. The C—C—O angles for the hydroxy groups are different as a result of the type of hybridization for the C atoms that are involved in these angles. The C—C—O angle for the phenol hydroxy group is 119.21 (13°, while the angle within the pendant alcohol is 111.99 (13°. The bond length involving the phenolic oxygen is 1.3820 (19 Å, which contrasts with that of the alcoholic oxygen which is 1.447 (2 Å. The former is conjugated with the aromatic ring and so leads to the observed shorter bond length.

  1. Diethyl 2,2-bis(3,5-di-tert-butyl-4-hydroxybenzylmalonate

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    Tao Zeng

    2012-02-01

    Full Text Available The title molecule, C37H56O6, possesses twofold symmetry, with the twofold axis passing through the quaternary C atom. In the crystal, neighbouring molecules are linked via O—H...O hydrogen bonds involving the phenol OH group and the carbonyl O atom, forming chains propagating in [101]. Within these chains, rings are formed with an R22(20 motif. There are also C—H...O interactions present within the rings.

  2. 4,4′-Di-tert-butyl-2,2′-bipyridine

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    Tatiana R. Amarante

    2009-08-01

    Full Text Available In the title compound, C18H24N2, the molecular unit adopts a trans conformation around the central C—C bond [N—C—C—N torsion angle of 179.2 (3°], with the two aromatic rings almost coplanar [dihedral angle of only 0.70 (4°]. The crystal packing is driven by co-operative contacts involving weak C—H...N and C—H...π interactions, and also the need to fill effectively the available space.

  3. tert-Butyl 4-formyl-1H-imidazole-1-carboxylate

    Directory of Open Access Journals (Sweden)

    Jun-Tao Kang

    2010-08-01

    Full Text Available In the crystal structure of the title compound, C9H12N2O3, weak intermolecular C—H...O hydrogen bonds link the molecules into chains. Further weak C—H...O hydrogen bonds together with π–π interactions [centroid–centroid distance = 3.672 (4 Å] between neighbouring chains lead to a double-chain structure propagating in [100].

  4. 4-tert-Butyl-2-[2-(1,3,3-trimethylindolin-2-ylideneethylidene]cyclohexanone

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    Graeme J. Gainsford

    2011-05-01

    Full Text Available The title molecule, C23H31NO, has two alternative cyclohexanone configurations at the 4-position in a ratio of 0.663 (3:0.337 (3. The plane of the five-membered planar ring in the indolin-2-ylidene subtends an angle of 2.19 (7° with its fused aromatic ring, an angle of 16.24 (8° with the plane of the major cyclohexanone configuration and an angle of 8.54 (15° with the bridging planar ethylidene C atoms. These last atoms subtend an angle of 8.37 (16° with the mean plane through the major cyclohexanone configuration. The molecules pack approximately parallel to the (overline{1}01 plane via C—H...π and C—H...O interactions.

  5. Di-n-butylammonium 2-[(3,5-di-tert-butyl-4-hydroxybenzylsulfanyl]benzoate

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    Abeer A. Alhadi

    2010-09-01

    Full Text Available The title salt, C8H20N+·C22H27O3S−, is a proton-transfer compound derived from the recently reported parent carboxylic acid [Alhadi et al. (2010. Acta Cryst. E66, o1787] by the addition of a second equivalent of di-n-butylamine, yielding the di-n-butylammonium carboxylate salt. The structure of the carboxylate anion resembles that of the parent carboxylic acid. The main difference lies in the position of the H atom in the 4-hydroxy group. In the anion the O—H bond is perpendicular, rather than parallel, to the benzyl ring. This position appears to facilitate hydrogen bonding to an O atom of the carboxylate group of a symmetry-related anion. In addition, there are three N—H...O hydrogen bonds. In contrast, the neutral species hydrogen bonds via a carboxylic acid dimer. The dihedral angle between the benzene rings in the anion is 79.19 (7°.

  6. 1,1'-Bis(tert-butyl-dimethyl-sil-yl)ferrocene.

    Science.gov (United States)

    Abri, Abdolreza; Soltani, Behzad; Ziegler, Christopher J; Engle, James T; Kia, Reza

    2013-01-01

    The asymmetric unit of the title compound, [Fe(C11H19Si)2], consists of one half of a ferrocene derivative. The Fe(II) atom lies on a twofold rotation axis, giving an eclipsed conformation for the cyclo-penta-dienyl ligands. No significant inter-molecular inter-actions are observed in the crystal structure.

  7. tert-Butyl N-benzyl-N-[4-(4-fluorobenzoylmethyl-2-pyridyl]carbamate

    Directory of Open Access Journals (Sweden)

    Pierre Koch

    2008-11-01

    Full Text Available In the crystal structure of the title compound, C25H25FN2O3, the pyridine ring makes dihedral angles of 75.1 (3, 39.4 (3 and 74.6 (3° with the phenyl ring, the carbamate plane and the 4-fluorophenyl ring, respectively. The phenyl ring makes dihedral angles of 77.2 (3 and 23.6 (3° with the carbamate plane and the 4-fluorophenyl ring, respectively. The 4-fluorophenyl ring is perpendicular to the carbamate plane, the dihedral angle between them being 89.5 (3°.

  8. tert-Butyl 2-borono-1H-pyrrole-1-carboxylate

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    Zheng Zhong

    2009-04-01

    Full Text Available In the crystal structure of the title compound, C9H14BNO4, the boronic acid group and carbamate groups are nearly co-planar with the pyrrole ring, making dihedral angles of 0.1 (2 and 2.2 (2°, respectively. Intramolecular and intermolecular O—H...O hydrogen bonds help to stabilize the structure, the latter interaction leading to inversion dimers..

  9. tert-Butyl N-{[5-(5-oxohexanamidopyridin-2-yl]amino}carbamate

    Directory of Open Access Journals (Sweden)

    Luisa Ronga

    2013-10-01

    Full Text Available In the crystal structure of the title compound, C16H24N4O4, molecules are linked by N—H...O hydrogen bonds between the carbonyl groups of the carbamoyl and amido functional groups and the amino groups, and by N—H...N hydrogen bonds between the amino group and the pyridine ring, forming two-dimensional networks parallel to the ab plane.

  10. Mono-N-methylation of primary amines with alkyl methyl carbonates over Y faujasites. 2. Kinetics and selectivity.

    Science.gov (United States)

    Selva, Maurizio; Tundo, Pietro; Perosa, Alvise

    2002-12-27

    In the presence of a Na-exchanged Y faujasite, the reaction of primary aromatic amines 1 with 2-(2-methoxyethoxy)methylethyl carbonate [MeO(CH(2))(2)O(CH(2))(2)OCO(2)Me, 2a] yields the corresponding mono-N-methyl derivatives ArNHMe with selectivity up to 95%, at substantially quantitative conversions. At 130 degrees C, the reaction can be run under diffusion-free conditions and is strongly affected by the solvent polarity: for instance, in going from xylene (epsilon(r) = 2.40) to triglyme (epsilon(r) = 7.62) as the solvent, the pseudo-first-order rate constant for the aniline (1a) disappearance shows a 5-fold decrease. In DMF (epsilon(r) = 38.25), the same reaction does not occur at all. Competitive adsorption of the solvent and the substrate onto the catalytic sites accounts for this result. The behavior of alkyl-substituted anilines ZC(6)H(4)NH(2) [Z = p-Me, p-Et, p-Pr, p-(n-Bu) (1b-e); Z = 3,5-di-tert-butyl- and 2,4,6-tri-tert-butylanilines (1f,g)] and p-alkoxyanilines p-ZC(6)H(4)NH(2) [Z = OMe, OEt, OPr, O-n-Bu (1b'-e')] clearly indicates a steric effect of ring substituents: as diffusion of the amine into the catalytic pores is hindered, the reaction hardly proceeds and the mono-N-methyl selectivity (S(M/D)) drops as well. Moreover, the strength of adsorption of the amine onto the catalyst influences the rate and the selectivity as well: the reaction of p-anisidine and p-toluidine-despite the higher nucleophilicity of these compounds-is slower and even less selective with respect to aniline. From a mechanistic viewpoint, the intermediacy of carbamates ArN(Me)CO(2)R [R = MeO(CH(2))(2)O(CH(2))(2)] is suggested. At 90 degrees C, the reaction of benzylamine (7)-a model for aliphatic amines-with dimethyl carbonate shows that the reaction outcome can be improved by tuning the amphoteric properties of the catalyst: in going from CsY to the more acidic LiY zeolite, methylation is not only more selective (S(M/D) ratio increases from 77% to 84%) but even much faster (Cs

  11. modelisation du comportement hydrologique du bassin versant du ...

    African Journals Online (AJOL)

    LGE

    caractéristiques physiographiques du bassin dans le modèle permet la mise en évidence de son ... espèces les plus hygrophiles du secteur ombrophile. ...... [13] - F. HENDRICKX, Impact hydrologique d‟un changement climatique sur le bassin du ... LOPES, On the effect of uncertainty in spatial distribution of rainfall on ...

  12. Bacterial degradation of tert-amyl alcohol proceeds via hemiterpene 2-methyl-3-buten-2-ol by employing the tertiary alcohol desaturase function of the Rieske nonheme mononuclear iron oxygenase MdpJ.

    Science.gov (United States)

    Schuster, Judith; Schäfer, Franziska; Hübler, Nora; Brandt, Anne; Rosell, Mònica; Härtig, Claus; Harms, Hauke; Müller, Roland H; Rohwerder, Thore

    2012-03-01

    Tertiary alcohols, such as tert-butyl alcohol (TBA) and tert-amyl alcohol (TAA) and higher homologues, are only slowly degraded microbially. The conversion of TBA seems to proceed via hydroxylation to 2-methylpropan-1,2-diol, which is further oxidized to 2-hydroxyisobutyric acid. By analogy, a branched pathway is expected for the degradation of TAA, as this molecule possesses several potential hydroxylation sites. In Aquincola tertiaricarbonis L108 and Methylibium petroleiphilum PM1, a likely candidate catalyst for hydroxylations is the putative tertiary alcohol monooxygenase MdpJ. However, by comparing metabolite accumulations in wild-type strains of L108 and PM1 and in two mdpJ knockout mutants of strain L108, we could clearly show that MdpJ is not hydroxylating TAA to diols but functions as a desaturase, resulting in the formation of the hemiterpene 2-methyl-3-buten-2-ol. The latter is further processed via the hemiterpenes prenol, prenal, and 3-methylcrotonic acid. Likewise, 3-methyl-3-pentanol is degraded via 3-methyl-1-penten-3-ol. Wild-type strain L108 and mdpJ knockout mutants formed isoamylene and isoprene from TAA and 2-methyl-3-buten-2-ol, respectively. It is likely that this dehydratase activity is catalyzed by a not-yet-characterized enzyme postulated for the isomerization of 2-methyl-3-buten-2-ol and prenol. The vitamin requirements of strain L108 growing on TAA and the occurrence of 3-methylcrotonic acid as a metabolite indicate that TAA and hemiterpene degradation are linked with the catabolic route of the amino acid leucine, including an involvement of the biotin-dependent 3-methylcrotonyl coenzyme A (3-methylcrotonyl-CoA) carboxylase LiuBD. Evolutionary aspects of favored desaturase versus hydroxylation pathways for TAA conversion and the possible role of MdpJ in the degradation of higher tertiary alcohols are discussed.

  13. C-14 and C-13 labelling of 4-terbutylanilinochlorethylurea. Marquage par [sup 14]C et [sup 3]C du terbutylanilino-4 chloroethyluree

    Energy Technology Data Exchange (ETDEWEB)

    Azim, M.; Madelmont, J.C.; Cussac, C.; Rapp, M. Maurizis, J.C.; Godeneche, D. (INSERM U 71, 63 - Clermont-Ferrand (France)); Gaudreault, R.G. (Hopital Saint-Francois d' Assise, Quebec (Canada). Centre de Recherche); Veyre, A. (INSERM U 71, 63 -Clermont-Ferrand (France) Clermont-Ferrand Univ., 63 -Clermont-Ferrand (France). Lab. de Biophysique Medicale)

    1993-11-01

    The labelling of 2-chloroethylisocyanate with [sup 14]C and [sup 13]C on the carbonyl group from 3-chloropropionic acid [sup 14]C and [sup 13]C is described. This isocyanate was used to synthesize 4-tert butyl [3-(2-chloro ethyl) ureido] (benzene). (Author).

  14. La maquette digitale du tunnel du LEP

    CERN Document Server

    Brouns, G

    2000-01-01

    Pour l'installation du LHC et son équipement périphérique (ligne cryogénique, câbles, tuyauterie, etc.) dans le tunnel du LEP, une maquette digitale CAO doit être faite. Après un rappel de la définition théorique du tunnel du LEP, cette LHC project Note décrit comment sont utilisées et intégrées d'anciennes et de nouvelles mesures du tunnel pour arriver à un ensemble de données qui permettent de construire la maquette digitale (CAO) du tunnel du LHC. Ensuite, les résultats sont comparés à leur valeur théorique d'une part, et aux anciennes valeurs disponibles d'autre part.

  15. Gallstone dissolution with methyl tertiary butyl ether: an experimental study on selection of gallstone by plain radiography and ultrasonography

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jong Beum; Ryu, Dae Sik; Oh, Seung Chul; Shim, Hyung Jin; Lee, Yong Chul; Kim, Young Goo; Song, In Sup; Kim, Kun Sang [Chung Ang University Hospital, Seoul (Korea, Republic of)

    1994-01-15

    The purpose of this study was to determine whether in vitro plain radiography and ultrasonography(US) could predict the outcome of gallstone dissolution with methyl tert-butyl ether(MTBE). The plain radiography and ultrasonography of 75 gallstones removed at surgery from 75 patients were obtained. The plain radiographic findings were grouped by their calcification pattern as group 1: lucent, group 2: central, group 3: diffuse and group 4: laminated. The ultrasonographic findings were grouped by their echo pattern as group: 1 arc shaped, clearly defined surface echo followed by distinct acoustic shadow, group 2: strong surface echo with gradually attenuating, meniscus shaped inner echo, group 3: strong surface echo with fill-in pattern of internal echo, group 4: strong surface echo with irregular inner echo and group 5: entirely discerning circumference, homogeneous internal echotexture. After imaging, the gallstones underwent MTBE dissolution for 6 hours. The residual weight of each stone was measured every 2 hours. The correlation between imaging findings and dissolution rate was retrospectively analysed. The radiolucent and central calcification stones were dissolved rapidly as compared with the diffuse and laminated calcification stones({rho} < .05). There was no statistically significant difference among the groups based on ultrasonographic findings alone. However, after exclusion of the certain calcification groups that were resistent to dissolution-diffuse or laminated calcification stones-all US groups except one that shows wholly circumscribed margin and homogeneous fill-in pattern of internal echo dissolved well to average 20% or less of the original weight({rho} < .05). MTBE dissolution can be tried in stones that meet both ultrasonographic (not a stone with homogeneous fill-in pattern of internal echo) and plain radiographic (radiolucent or central calcification stone) criteria.

  16. Enzymatic synthesis of 3-(tert-butyldimethylsilyloxy)glutaric methyl monoester by immobilized lipase%固定化脂肪酶合成3-TBDMSO戊二酸甲酯

    Institute of Scientific and Technical Information of China (English)

    王霞; 董文癑; 陈雄飞; 付雁

    2014-01-01

    Lipase-catalysed reactions were considered as an effective method to prepare pure enantiomers,based on the esterification of alcohol,acid,or lactone in non-aqueous phase under mild reaction conditions.An enzymatic alcoholysis of 3-(tert-butyldimethylsilyloxy ) glutaric anhydride (3-TBDMSO-GA ) with methanol for preparing 3-(tert-butyldimethylsilyloxy)glutaric methyl monoester (3-TBDMSO-GMM)was studied using immobilized Lipase Novozym 435 .The different solvents including tetrahydrofuran,ethyl acetate,diethyl ether,methyl tert-butyl ether and toluene were investigated under mild conditions.It shows that methyl tert-butyl ether is the most effective solvent in the alcoholysis reaction.The effects of reaction time and temperature,enzyme amount,water activity, substrate concentration,molar ratio of alcohol to substrate on the substrate conversion and the selectivity were studied using the analysis of high performance liquid chromatography with C18 column.The optimal reaction conditions were as follows:temperature 25 ℃,enzyme mass concentration 30 mg/mL,the molar ratio of alcohol to 3-TBDMSO-GA 1.0,anhydride concentration 100 mmol/L,pH 6.5,water activity 0.66 and reaction time 6 h. The product of colorless crystal was obtained through extraction method followed by crystallization purification.By using 1 H-NMR,the product was confirmed as 3-TBDMSO-GMM.CD spectroscopy demonstrates that the product has an enantiomeric excess.%脂肪酶主要催化醇、酸、内酯的酯化反应,脂肪酶催化反应可在非水溶剂中进行,并且反应条件温和,被认为是制备单一对映异构体的有效方法。文中利用固定化脂肪酶Novozym 435催化3-TBDMSO戊二酸酐不对称醇解制备3-TBDMSO戊二酸甲酯,通过高效液相色谱考察了不同反应条件对底物转化率、产物选择性的影响规律。实验研究了四氢呋喃、乙酸乙酯、乙醚、甲基叔丁基醚和甲苯5种溶剂对酶催化反应的影响,结果表明:在甲

  17. Learning about Cri du Chat Syndrome

    Science.gov (United States)

    ... Learning About Prostate Cancer Learning About Cri du Chat Syndrome What is cri du chat syndrome? What ... cri du chat syndrome What is cri du chat syndrome? Cri du chat syndrome - also known as ...

  18. "Cirque du Freak."

    Science.gov (United States)

    Rivett, Miriam

    2002-01-01

    Considers the marketing strategies that underpin the success of the "Cirque du Freak" series. Describes how "Cirque du Freak" is an account of events in the life of schoolboy Darren Shan. Notes that it is another reworking of the vampire narrative, a sub-genre of horror writing that has proved highly popular with both adult and…

  19. "Cirque du Freak."

    Science.gov (United States)

    Rivett, Miriam

    2002-01-01

    Considers the marketing strategies that underpin the success of the "Cirque du Freak" series. Describes how "Cirque du Freak" is an account of events in the life of schoolboy Darren Shan. Notes that it is another reworking of the vampire narrative, a sub-genre of horror writing that has proved highly popular with both adult and…

  20. Restaurant du Rivage, Vevey

    OpenAIRE

    Basini, Sari Bianca; Glocki, Ryszard Nikodem

    2015-01-01

    Après cinquante ans de mutilations, d'abandon et de spéculations économiques, le complexe du château de l'Aile et de la salle du Castillo à Vevey doit redéfinir son rôle public par rapport à la place du Marché et au Jardin du Rivage. S'appuyant sur la mémoire historique en ajoutant une unité à l'ensemble, nous créons un îlot regroupant des fonctions publiques. Il dessert ainsi l'espace ouvert environnant en articulant la relation entre le jardin et la place. L'élargissement de la promenade du...

  1. Empty-level structure and reactive species produced by dissociative electron attachment to tert-butyl peroxybenzoate.

    Science.gov (United States)

    Modelli, Alberto; Pshenichnyuk, Stanislav A

    2012-04-12

    The energy and nature of the gas-phase temporary anion states of tert-butylperoxybenzoate in the 0-6 eV energy range are determined for the first time by means of electron transmission spectroscopy (ETS) and appropriate theoretical calculations. The first anion state, associated with electron capture into a delocalized π* MO with mainly ring and carbonyl character, is found to lie close to zero energy, i.e., sizably more stable (about 2 eV) than the ground (σ*) anion state of saturated peroxides. Dissociative decay channels of the unstable parent molecular anions are detected with dissociative attachment spectroscopy (DEAS), as a function of the incident electron energy, in the 0-14 eV energy range. A large DEA cross-section, with maxima at zero energy, 0.7 and 1.3 eV, is found for production of the (m/e = 121) PhCOO(-) anion fragment, together with the corresponding tert-butoxy neutral radical, following cleavage of the O-O bond. Although with much smaller intensities, a variety of other negative currents are observed and assigned to the corresponding anion fragments with the support of density functional theory calculations.

  2. Catalytic oxidation of cyclohexane to cyclohexanone and cyclohexanol by tert-butyl hydroperoxide over Pt/oxide catalysts

    Indian Academy of Sciences (India)

    I Rekkab-Hammoumraoui; A Choukchou-Braham; L Pirault-Roy; C Kappenstein

    2011-08-01

    Heterogeneous oxidation of cyclohexane with tertiobutyl hydroperoxide was carried out on Pt/oxide (Al2O3, TiO2 and ZrO2) catalysts in the presence of different solvents (acetic acid and acetonitrile). The catalysts were prepared using Pt(NH3)2(NO2)2 as a precursor and characterized by chemical analysis using the ICP–AES method, XRD, TEM, FTIR and BET surface area determination. The oxidation reaction was carried out at 70°C under atmospheric pressure. The results showed the catalytic performance of Pt/Al2O3 as being very high in terms of turnover frequency.

  3. Bis(η3-2-tert-butyl-1-trimethylsilyl-3-phenyl-1-azaallylnickel(II

    Directory of Open Access Journals (Sweden)

    Junsheng Hao

    2011-04-01

    Full Text Available The title compound, [Ni(C15H24NSi2], is a homoleptic metal–η3-azaallyl centrosymmetric complex containing two azaallyl ligands bound in an η3-manner to an NiII atom located on a center of symmetry. The overall coordination about the NiII atom is square-planar. The C and N atoms of the azaallyl group are sp2-hybridized. The uneven Ni—C and Ni—N distances [2.045 (5/2.060 (6 and 1.916 (5 Å] are influenced by a steric hindering effect from the nearby benzene ring.

  4. Influence of the Mixing State of tert- Butyl Alcohol-water Mixtures on the Conformation of Bovine Serum Albumin

    Institute of Scientific and Technical Information of China (English)

    MA,Lin; WANG,Xu; XU,Li; HE,Wei-Ren; WEI,Zhi-Qiang; LIN,Rui-Sen

    2008-01-01

    The hydrodynamic radii of bovine serum albumin (BSA) in TBA-water mixtures were determined by dynamic light scattering measurements and utilized to investigate the conformational change of BSA in TBA-water mixtures, together with the analysis of the fluorescence spectra and UV-vis absorption spectra of BSA. Meanwhile, static light scattering measurements were used to probe the mixing state of the binary mixtures of TBA-water and the ternary mixtures of BSA-TBA-water and its influence on the conformation of the protein. A close relationship between the mixing state of TBA-water mixtures and the conformation of BSA was observed. The mixing state of TBA-water mixture at a low concentration was characterized by the clathrate hydrate of TBA caged by water molecules and it was found that hydrophobic binding of TBA to nonpolar groups of BSA in general destabilized the native structure of the protein, however, addition of a small amount of TBA attenuated the hydrophobic interactions among nonpolar groups of the protein and promoted a more ordered conformation. The results clearly showed that clustering of TBA at a high concentration reduced the effectiveness on destabilization of the compact conformation of proteins.

  5. UV absorption spectra and kinetics for alkyl and alkyl peroxy radicals originating from di-tert-butyl ether

    DEFF Research Database (Denmark)

    Nielsen, O.J.; Sehested, J.; Langer, S.;

    1995-01-01

    the wavelength range 220-330 nm. At 240 nm, sigma((CH3)3COC(CH3)2CH2) = (3.6 +/- 0.4) X 10(-18) cm(2) molecule(-1) and at 260 nm, sigma((CH3)3COC(CH3)2CH2) = (3.8 +/- 0.3) X 10(-18) cm(2) molecule(-1) have been obtained. The observed rate constants for the self-reaction of (CH3)(3)COC(CH3)(2)CH2 and (CH3)(3)COC......(CH3)(2)CH2O2 radicals were found to be (2.9 +/- 0.2) X 10(-11) cm(3) molecule(-1) s(-1) and (2.7 +/- 0.2) X 10(-12) cm(3) molecule(-1) s(-1), respectively. For the reaction of the alkyl radical with O-2 in 1 atm pressure of SF6 a rate constant of (7.2 +/- 1.1) X 10(-13) cm(3) molecule(-1) s(-1......) was found. The rate constants for the reaction of the alkyl peroxy radicals with NO and NO2 were determined to be (1.8 +/- 0.2) X 10(-12) and (9.9 +/- 1.3) X 10(-12) cm(3) molecule(-1) s(-1), respectively. As a part of the work the rate constants k(F + DTBE) and k(OH + DTBE) were determined to be (2.6 +/- 0.6...

  6. tert-Butyl N-((1S-2-hydroxy-1-{N′-[(1E-4-methoxybenzylidene]hydrazinecarbonyl}ethylcarbamate

    Directory of Open Access Journals (Sweden)

    Alessandra C. Pinheiro

    2011-07-01

    Full Text Available The molecule of the title compound, C16H23N3O5, is twisted about the chiral C atom, the dihedral angle formed between the amide residues being 79.6 (3°. The conformation about the imine bond [1.278 (5 Å] is E. In the crystal, O—H...O and N—H...O hydrogen bonding between the hydroxy, amine and carbonyl groups leads to the formation of supramolecular layers, which stack along the c-axis direction.

  7. Bis({tris[2-(3,5-di-tert-butyl-2-oxidobenzylideneaminoethyl]amine}cerium(III diethyl ether solvate

    Directory of Open Access Journals (Sweden)

    Peter Dröse

    2010-11-01

    Full Text Available The title compound, 2[Ce(C51H75N4O3]·C4H10O, was obtained in high yield (92% by reduction of (TRENDSALCeIVCl [TRENDSAL is N,N′,N′′-tris(3,5-di-tert-butylsalicylidenatoaminotriethylamine] with potassium in THF. The bulky tripodal TRENDSAL ligand effectively encapsulates the central CeIII cation with a Ce—N(imine distance of 2.860 (2 Å and an average C—N(amine distance of 2.619 Å within a distorted monocapped octahedral coordination.

  8. Atlas du Liban

    Directory of Open Access Journals (Sweden)

    Ramez Philippe Maalouf

    2008-11-01

    Full Text Available Compte-rendu de l’ouvrage Atlas du Liban: territoires et société, sous la direction d’Éric Verdeil, Ghaleb Faour et Sébastien Velut, édition franco-libanaise de l’IFPO (Institut Français du Proche-Orient et du CNRS Liban (Conseil National de la Recherche Scientifique – Liban, Beyrouth 2007.Resenha do livro Atlas du Liban: territoires et société, sob a direção de Éric Verdeil, Ghaleb Faour e Sébastien Velut, editado por iniciativa franco-libanesa do IFPO (Institut Français du Proche-Orient e pelo CNRS Liban (Conseil National de la Recherche Scientifique – Liban, Beirute, 2007.Review of Atlas du Liban: territoires et société, edited by Éric Verdeil, Ghaleb Faour and Sébastien Velut, french-lebanese edition by IFPO (Institut Français du Proche-Orient and CNRS Liban (Conseil National de la Recherche Scientifique – Liban Beirut, 2007.

  9. Ecologie du phytoplancton du lac Kivu

    Directory of Open Access Journals (Sweden)

    Sarmento, H.

    2008-01-01

    Full Text Available Speciation within the African Coffee Pathogen. Cet article analyse s'il est avantageux d'utiliser le compost au lieu de l'engrais minéral pour produire la laitue dans la zone urbaine et péri-urbaine de Yaoundé. Les résultats de terrain montrent l'obtention de rendements et profits plus élevés lorsqu'on utilise le compost. Les résultats de la fonction de production Cobb-Douglas prouvent que l'utilisation du compost est statistiquement significative pour expliquer la variation de rendement de la laitue et que le compost est l'intrant le plus productif. D'autres résultats montrent que le compost fournit la matière organique utile au sol et que les besoins d'irrigation en eau de la culture sont réduits grâce à l'utilisation du compost. Par conséquent, malgré le fait que l'application du compost demande une main-d'oeuvre beaucoup plus élevée, son utilisation est généralement bénéfique pour les agriculteurs vivant aux alentours de Yaoundé. Les programmes de vulgarisation de cet intrant pour encourager son adoption devraient donc figurer parmi les points prioritaires dans la politique agricole du gouvernement camerounais.

  10. Nitric oxide inhibitor N omega -nitro-l-arginine methyl ester potentiates induction of heme oxygenase-1 in kidney ischemia/reperfusion model: a novel mechanism for regulation of the oxygenase.

    Science.gov (United States)

    Mayer, Robert D; Wang, Xiaojun; Maines, Mahin D

    2003-07-01

    The biological significance of the heme oxygenase (HO) system's response to stress reflects functions of its products-CO and bile pigments. CO is a messenger molecule, whereas bile pigments are antioxidants and modulators of cell signaling. Presently, an unexpected mechanism for sustained suprainduction of renal HO-1 following ischemia/reperfusion injury is described. Inhibition of nitric-oxide synthase (NOS) activity by Nomega-nitro-l-arginine methyl ester (l-NAME) at the resumption of reperfusion of rat kidney subjected to bilateral ischemia (30 min) was as effective as the most potent HO-1 inducer, the spin trap agent n-tert-butyl-alpha-phenyl nitrone (PBN), in causing sustained suprainduction of HO-1 mRNA. PBN forms stable radicals of oxygen and nitrogen. Twenty-four hours after reperfusion, HO-1 mRNA measured approximately 30-fold that of the control in the presence of l-NAME treatment; in its absence, the transcript increased to only approximately 5-fold. At 4 h in the presence or absence of the l-NAME HO-1, mRNA was increased by approximately 30-fold. The transcript was translated to active protein as indicated by Western blotting, immunohistochemistry, and activity analyses. l-NAME was not effective given 1 h after resumption of reperfusion. Suprainduction was restricted to the kidney and not detected in the heart and aorta; ferritin expression in the kidney was not effected. It is reasoned that in tissue directly insulted by ischemia/reperfusion, increased production of NO radicals promotes the loss of HO-1 transcript. Because the absence of NO radicals and presence of PBN had a similar effect on HO-1, we propose that suprainduction of the gene is mainly caused by O2 radicals formed on reperfusion. Inhibition of NOS is potentially useful for sustained induction of HO-1 in organs that will be subjected to oxidative-stress insult.

  11. 碳酸二甲酯和乙酸甲酯合成丙二酸二甲酯的研究%Synthesis of dimethyl malonate from dimethyl carbonate and methyl acetate

    Institute of Scientific and Technical Information of China (English)

    王轩; 李伟; 沈荣春

    2016-01-01

    Dimethyl malonate (DMM) was synthesized by Claisen ester condensation reaction between dimethyl carbonate (DMC) and methyl acetate (MA). The catalytic activities of several catalysts, potassium tert-butylate (C4H9OK), sodium t-butoxide (C4H9ONa), sodium methoxide (CH3ONa) and sodium hydride (NaH), were evaluated, and the effects of reactant ratio, temperature, time, catalyst dosage and solvents on the reaction were investigated. Results showed that under the reaction conditions of DMC/MA/CH3ONa mole ratio of 5:1:3.6, 90℃, reaction time of 2h and no solvent, the MA conversion and DMM selectivity could reach 70%and 99%, respectively.%研究了以碳酸二甲酯(DMC)和乙酸甲酯(MA)为原料合成丙二酸二甲酯,评价了叔丁醇钾(C4H9OK)、叔丁醇钠(C4H9ONa)、甲醇钠(CH3ONa)和氢化钠(NaH)等催化剂对该克莱森酯缩合反应的催化活性,考察了物料配比、反应温度、反应时间、催化剂用量和溶剂等因素对反应的影响。结果表明,当n(DMC):n(MA):n(CH3ONa)=5:1:3.6,反应温度90℃,反应时间2h时和无溶剂时乙酸甲酯的转化率达到70%,丙二酸二甲酯(DMM)的选择性为99.0%。

  12. MODELES EPIDEMIOLOGIQUES DU SIDA

    OpenAIRE

    M MERAIHI; F. L RAHMANI

    2009-01-01

    L’objectif de cet article est de présenter la modélisation mathématique de la propagation de l’infection dans le contexte de la transmission du virus de l’immunodéficience humaine (VIH) et du syndrome d’immunodéficience acquise (SIDA). Ces modèles sont basés en partie sur les modèles proposés dans le domaine de la modélisation mathématique du SIDA.

  13. Types du Caucase

    OpenAIRE

    Makhacheva, Taus

    2015-01-01

    Tiré du site Internet de Onestar Press: "Types du Caucase - antique postcard collection/ 2013 to the present time. Coming from the personal archive of the artist, these postcards date back to the 19th century and can be considered representative for the "popularized ethnography" of the Russian Empire. Their primitive typology follows the classical rules of exotization : they depict "pittoresque" groups from various tribes, families or nationalities, or representatives of diverse professions. ...

  14. Les outils du CERN

    CERN Multimedia

    1999-01-01

    C'est le plus grand centre mondial de recherche en physique des particules. Les outils du Laboratoire, accélérateurs et détecteurs de particules, figurent parmi les instruments scientifiques les plus complexes au monde. Des prix Nobels ont d'ailleurs été attribués aux physiciens du CERN pour leurs développements.

  15. Le rythme du silence

    OpenAIRE

    Meschonnic, Henri

    2017-01-01

    1. Pour rompre le silence Dire « rythme du silence », c’est non seulement penser le silence comme langage, et parfois la réalisation maximale du langage, mais aussi parcourir les acceptions de la notion de silence. De ce qui n’est pas dit, ou qu’on est incapable de dire à ce que les mots ne peuvent pas dire, le fameux indicible, mais aussi l’innommable, et la censure, faire silence sur, jusqu’au problème poétique. Il y a aussi une langue de bois du silence. Et aussi le silence de ce qu’on ent...

  16. A Novel Strategy Towards the Asymmetric Synthesis of Orthogonally Funtionalised 2-N-Benzyl-N-α-methylbenzylamino- 5-carboxymethyl-cyclopentane-1-carboxylic acid.

    Directory of Open Access Journals (Sweden)

    Julio G. Urones

    2004-04-01

    Full Text Available The asymmetric synthesis of the orthogonally funtionalised compounds tert-butyl 2-N-benzyl-N-α-methylbenzylamino-5-methoxycarbonylmethylcyclopentane- 1-carboxylate and methyl 2-N-benzyl-N-α-methylbenzylamino-5–carboxymethylcyclo- pentane-1-carboxylate by a domino reaction of tert-butyl methyl (E,E-octa-2,6- diendioate with lithium N-α-methylbenzyl-N-benzylamide initiated by a Michael addition, subsequent 5-exo-trig intramolecular cyclisation and posterior selective hydrolysis with trifluoroacetic acid is reported.

  17. La profanation du montage

    OpenAIRE

    Hildebrandt, Toni

    2017-01-01

    Cet article examine les liens entre, pour l’aspect technique, le plan séquence et le montage, et, pour l’aspect philosophico-historique, la vie quotidienne et la politique mondiale, du point de vue d’une profanation capable de désamorcer la puissance et avec une attention particulière portée à l’unique film expérimental de Pasolini : La sequenza del fiore di (1968). Ce court métrage n’a pas seulement un statut spécial dans la filmographie de Pasolini, il marque aussi un tournant du tragique v...

  18. Historique du Web

    CERN Multimedia

    TV8 Mont-Blanc

    1995-01-01

    Documentaire court qui retrace l'implication de différentes personalités à la création du Web. Entrevues avec Robert Cailliau, Chris Llewellyn-Smith, David Williams, Tim Berners-Lee, Mike Sendall, Brian Carpenter.

  19. La foret du Banco

    NARCIS (Netherlands)

    Koning, de J.

    1983-01-01

    Deze publicatie over het Nationaal Park 'La Forêt du Banco' nabij Abidjan, Ivoorkust, verschijnt als resultaat van vier jaar veldwerk (1972-1976) in dat land.Het Centre Néerlandais, onderzoeks- en stageverblijf van de Landbouwhogeschool, was basis en de faciliteiten verleend door het Franse ORSTOM-i

  20. Origine du vieux slave

    Directory of Open Access Journals (Sweden)

    Witold Mańczak

    2005-12-01

    Full Text Available Comme, pour prouver l'identité du vieux slave et du vieux bulgare, on invoque uniquement des critères phonétiques, rappelons que l'orientaliste allemand du XVIIe siècle Ludolf affirmait déjà que "die Sprachverwandtschaft offenbart sich nicht im Wörterbuch, sondern in der Grammatik"3. Pendant les 300 dernières années, tellement d'autorites ant approuvé !l’opinion de Ludolf qu'elle est devenue un dogme de la linguistique. Pourtant il nous est venu à l'esprit de le confronter avec des faits et ainsi nous sommes arrivé à la conclusion qu'en réalité, c'est le vocabulaire (et non la phonétique et la flexion qui décide du degre de la parenté des langues4. Voici des arguments à l'appui de cette thèse.

  1. DNA Methylation

    OpenAIRE

    Alokail, Majed S.; Alenad, Amal M.

    2015-01-01

    The DNA of E. coli contains 19,120 6-methyladenines and 12,045 5-methylcytosines in addition to the four regular bases and these are formed by the postreplicative action of three DNA methyltransferases. The majority of the methylated bases are formed by the Dam and Dcm methyltransferases encoded by the dam (DNA adenine methyltransferase) and dcm (DNA cytosine methyltransferase) genes. Although not essential, Dam methylation is important for strand discrimination during repair of replication e...

  2. The occurrence of methyl tert-butylether (MTBE) in drinking water and sources for drinking water; De aanwezigheid van methyl tert-butylether (MTBE) in drinkwater en drinkwaterbronnen

    Energy Technology Data Exchange (ETDEWEB)

    Morgenstern, P.P.; De Korte, G.A.L.; Hogendoorn, E.A.; Versteegh, J.F.M.

    2002-07-01

    In 2001 the National Institute for Public Health and the Environment (RIVM) in the Netherlands conducted a drinking water measurement programme in co-operation with the Netherlands Waterworks Association (VEWIN) for methyl tert-butyl ether (MTBE) in drinking water and the corresponding sources. This study, consisting of two sampling periods, shows a generally low concentration of MTBE in drinking water at the selected drinking water plants. The selection of sampling locations was based on the vulnerability of the water catchment area. Measurements in the June/July period showed a concentration of <0.01 {mu}g/l in 22 samples of raw water; the average concentration was 0.07 {mu}g/l and the highest 0.42 {mu}g/l. The average concentration in drinking water in September/October was 0.09 {mu}g/l and the maximum 2.9 {mu}g/l. This maximum concentration was unusual, considering that the second highest value was 0.14 {mu}g/l MTBE. The raw water (both groundwater and surface water) samples registered a concentration of <0.5 {mu}g/l; the highest concentration in surface water was 3.2 {mu}g/l. However, at one location a relatively high concentration (11.9 {mu}g/l) was found in an individual groundwater well. This contamination could be attributed to a local source. The main conclusion here is that MTBE occurs in drinking water, although the concentrations are generally very low (<0.14 {mu}g/l), with a maximum value of 2.9 {mu}g/l. There are no effects on health expected. It is, however, recommended to screen for MTBE in groundwater at locations with a history of or experience with soil contamination. Taking precautions for future spills at petrol stations remains priority number one. [Dutch] Het RIVM heeft in samenwerking met VEWIN in 2001 een meetprogramma uitgevoerd voor de stof methyl tert-butylether (MTBE) in drinkwater en drinkwaterbronnen. In de periode juni/juli 2001 is een orieenterend meetprogramma uitgevoerd. De concentratie MTBE in ruwwater van 22 pompstations (in

  3. DNA methylation

    DEFF Research Database (Denmark)

    Williams, Kristine; Christensen, Jesper; Helin, Kristian

    2012-01-01

    DNA methylation is involved in key cellular processes, including X-chromosome inactivation, imprinting and transcriptional silencing of specific genes and repetitive elements. DNA methylation patterns are frequently perturbed in human diseases such as imprinting disorders and cancer. The recent...... discovery that the three members of the TET protein family can convert 5-methylcytosine (5mC) into 5-hydroxymethylcytosine (5hmC) has provided a potential mechanism leading to DNA demethylation. Moreover, the demonstration that TET2 is frequently mutated in haematopoietic tumours suggests that the TET...... proteins are important regulators of cellular identity. Here, we review the current knowledge regarding the function of the TET proteins, and discuss various mechanisms by which they contribute to transcriptional control. We propose that the TET proteins have an important role in regulating DNA methylation...

  4. Aux origines du monde

    CERN Multimedia

    2004-01-01

    "C'est l'histoire d'une aventure humaine, scientifique, international qui a vu le jour il y a cinquante ans, aux confins de la Suisse et du département de l'Ain. Le plus grand laboratoire de physique des particules du monde, le Cern, a été fondé en 1954. Les festivités organisées à l occasion de cet anniversaire connaîtront leur point d'orgue le 16 octobre prochain, avec portes-ouvertes, accueil de personallités et inauguration d'un monumnet spécifique, le Globe de l'innovation" (2 pages)

  5. Images du Valais

    Directory of Open Access Journals (Sweden)

    Micheline COSINSCHI

    1995-06-01

    Full Text Available Une étude des revenus fiscaux ventilés par branches économiques permet de clore un ouvrage portant sur ce canton alpin suisse par excellence qu’est le Valais. Pris comme traceurs de l’activité régionale, l’analyse de leurs configurations spatiales permet une évaluation pouvant être considérée comme une mesure de l’efficacité différentielle du système socio-spatial valaisan. L’article décrit certains processus qui ont permis la réalisation du dernier chapitre d’un atlas portant sur le Valais.

  6. CHOEUR DU CERN

    CERN Multimedia

    CHOEUR DU CERN

    2010-01-01

    Les répétitions du chœur du CERN reprendront le mercredi 15 septembre à 20.00 heures à l’amphithéâtre principal – bâtiment 500. Au programme la préparation de notre concert de Noël avec la Missa Brevis, KV115, de Léopold Mozart et de la musique de Noël d’Europe. Les personnes qui aiment chanter, notamment des sopranes et des ténors, sont les bienvenues. Pour tout contact s’adresser à : Baudouin Bleus - (tél.CERN 767 82 44) -(baudouin.bleus@cern.ch) ou Martin Gatehouse ( martin.gatehouse@wanadoo.fr) ou Jean-Paul Diss (jean-pauldiss@wanadoo.fr).  

  7. Les Cahiers du CREAD

    African Journals Online (AJOL)

    Admin

    les littératures économique et gestionnaire, mais souvent dans ces travaux, l'effet de ... chiffre d'affaires du nouvel ensemble résultant de la vente des produits mieux .... syndicalisme, droit de grève), fiscales (différents taux d'imposition, etc.) .... nouvel ensemble et aussi, les différentes relations avec les alliances verticales ...

  8. La mesure du danger

    CERN Document Server

    Manceron, Vanessa; Revet, Sandrine

    2014-01-01

    La mesure du danger permet d’explorer des dangers de nature aussi diverse que la délinquance, la pollution, l’écueil maritime, la maladie ou l’attaque sorcellaire, l’extinction d’espèces animales ou végétales, voire de la Planète tout entière. Au croisement de la sociologie, de l’anthropologie et de l’histoire, les différents articles analysent les pratiques concrètes de mesure pour tenter de comprendre ce qui se produit au cours de l’opération d’évaluation du danger sans préjuger de la nature de celui-ci. L’anthropologie a contribué à la réflexion sur l’infortune en s’intéressant aux temporalités de l’après : maladies, catastrophes, pandémies, etc. et en cherchant à rendre compte de l’expérience des victimes, de leur vie ordinaire bouleversée, de la recomposition du quotidien. Elle s’intéresse aussi aux autres types de mesures, les savoirs incorporés, qui reposent sur l’odorat, la vue ou le toucher et ceux qui ressortent d’une épistémologie « non ...

  9. Har du sikret din alderdom?

    DEFF Research Database (Denmark)

    Kiens, Bente; Aagaard, Peter Gjerndrup

    2006-01-01

    Daglig fysisk aktivitet kan betragtes som indbetaling op din personlige helbredspension. Jo mere du sætter ind på kontoen, og jo oftere du gør det, jo større er sandsynligheden for, at du lever længere og får et sundere helbred. Og det er aldrig for sent at starte med indbetalingerne....

  10. Les pirogues du Maroni

    Directory of Open Access Journals (Sweden)

    Sophie François

    2012-04-01

    Full Text Available Sur le Maroni, fleuve frontière entre la Guyane française et le Surinam, les pirogues amarrées le long des berges se comptent par centaines. Elles représentent le seul moyen de transport pour les milliers de personnes vivant sur les rives du Maroni. Les différentes formes de pirogues sont révélatrices de la diversité géographique du Maroni et de la diversité culturelle des populations. Les Amérindiens du littoral naviguent uniquement dans l’estuaire du fleuve. Ils construisent des pirogues larges, hautes et terminées à la poupe par une haute étrave qui fend les vagues. Ces pirogues sont construites à partir d’une coque monoxyle expansée et rehaussée d’un ou de deux bordages. En chauffant la grume évidée, le bois acquiert une certaine plasticité qui permet d’écarter les flancs et d’obtenir une coque très large à partir d’un arbre de faible diamètre. Les Bushinenge, populations d’origine africaine qui ont déserté les grandes plantations de la Guyane hollandaise dès le début du XVIIe siècle et se sont installées sur les deux rives du Maroni, ont développé des formes de pirogues adaptées au passage des sauts. Leurs pirogues, construites également en expansant la coque au feu, sont étroites et longues et possèdent des extrémités curvilignes qui dépassent largement au–dessus du bordage. Les longues pirogues à moteur comme les canots–pagaies sont ornés de motifs d’entrelacs appelés tembé ; et de décors d’inspiration contemporaine. L’inventaire des pirogues du Maroni a mis en évidence la richesse et la vitalité du patrimoine nautique de cette région au début du XXIe siècle, tant au niveau des formes des embarcations que des décors et des pratiques de navigation.On the Maroni river, natural border between French Guyana and the Surinam, canoes tied to the river banks can be counted by the hundreds. They are the only mean of transportation for thousands of people living along the

  11. L'Origine du Monde

    CERN Multimedia

    CNET & Ecole Polytechnique Paris; Vincent Ferreira

    1996-01-01

    Création, théologie, science, découverte, recherche, religion, condition humaine.Avec Maurice Jacob physicien, Hubert Curien Président du Conseil du CERN, Michael Doser physicien, Frère Emile Communauté de Taizé.

  12. discours du Directeur General

    CERN Document Server

    CERN. Geneva

    2007-01-01

    L'année 2007 est une année très spéciale pour le CERN. Je vous propose de nous retrouver pour faire le point sur les activités en cours. Rendez-vous le mercredi 27 juin à 15h00 dans l'amphithéâtre principal. La transmission simultanée sera assurée dans les amphithéâtres IT, AT, AB Prevessin et dans la Salle du Conseil. Robert Aymar

  13. Molecular and vibrational structure of thiosulfonate S-esters

    DEFF Research Database (Denmark)

    Luu, Thi Xuan Thi; Duus, Fritz; Spanget-Larsen, Jens

    2013-01-01

    S-methyl methanethiosulfonate (1), S-ethyl ethanethiosulfonate (2), S-isopropyl propane-2-thiosulfonate (3), S-tert-butyl 2-methylpropane-2-thiosulfonate (4), and S-phenyl benzenethiosulfonate (5) were investigated by FTIR spectroscopy in liquid solution and by quantum chemical calculations (B3LY...

  14. Model description and kinetic parameter analysis of MTBE biodegradation in a packed bed reactor

    DEFF Research Database (Denmark)

    Waul, Christopher Kevin; Arvin, Erik; Schmidt, Jens Ejbye

    2008-01-01

    A dynamic modeling approach was used to estimate in-situ model parameters, which describe the degradation of methyl tert-butyl ether (MTBE) in a laboratory packed bed reactor. The measured dynamic response of MTBE pulses injected at the reactor's inlet was analyzed by least squares and parameter...

  15. Selective functionalization of calix[6]arenes at the upper rim

    NARCIS (Netherlands)

    de Mendoza, Javier; Carramolino, Mar; Cuevas, Felix; Nieto, Pedro M.; Prados, Pilar; Reinhoudt, David

    1994-01-01

    Methylation of partially O-benzylated p-tert-butylcalix[6]arenes followed by hydrogenolysis constitutes an efficient method for the preparation of partially O-alkylated Calix[6]arenes in gram amounts, without adhering to column chromatography separations. Selective de-tert-butylation followed by

  16. MTBE BIOREMEDIATION WITH BIONETS CONTAINING ISOLITE, PMI, SOS ON AIR

    Science.gov (United States)

    Methyl tert-Butyl Ether (MTBE), a gasoline additive, is a persistent and foul tasting contaminant that is more mobile in ground water than BTEX. It is turning up at many American crossroads. This study's objective was to determine if biologically active in situ Bionets could bior...

  17. Achieving a More Sustainable Process Design for the Production of Methanol

    DEFF Research Database (Denmark)

    Plaza, Cristina Calvera; Gonzalez Garcia, Marta; Callau, Ana Diez;

    Methanol is an important chemical product because it can be used as a raw material for the production of other chemicals (1), for example dimethyl carbonate, formaldehyde and methyl tert-butyl ether and it is also one of the most produced bulk chemicals with an annual global production of 100 mil...

  18. Persulfate Oxidation of MTBE- and Chloroform-Spent Granular Activated Carbon

    Science.gov (United States)

    Activated persulfate (Na2S2O8) regeneration of methyl tert-butyl ether (MTBE) and chloroform-spent GAC was evaluated in this study. Thermal-activation of persulfate was effective and resulted in greater MTBE removal than either alkaline-activation or H2O2–persulfate binary mixtur...

  19. Effect of Water Clustering on the Activity of Candida antarctica Lipase B in Organic Medium

    DEFF Research Database (Denmark)

    Banik, Sindrila Dutta; Nordblad, Mathias; Woodley, John M.

    2017-01-01

    The effect of initial water activity of MTBE (methyl tert-butyl ether) medium on CALB (Candida antarctica lipase B) catalyzed esterification reaction is investigated using experimental methods and classical molecular dynamics (MD) simulations. The experimental kinetic studies show that the initial...

  20. CHEMOMETRICS IN BIOANALYTICAL SAMPLE PREPARATION - A FRACTIONATED COMBINED MIXTURE AND FACTORIAL DESIGN FOR THE MODELING OF THE RECOVERY OF 5 TRICYCLIC AMINES FROM PLASMA AFTER LIQUID-LIQUID-EXTRACTION PRIOR TO HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY

    NARCIS (Netherlands)

    WIELING, J; MENSINK, CK; JONKMAN, JHG; COENEGRACHT, PMJ; DUINEVELD, CAA; DOORNBOS, DA

    1993-01-01

    A general systematic approach is described for the chemometric modelling of liquid-liquid extraction data of drugs from biological fluids. Extraction solvents were selected from Snyder's solvent selectivity triangle: methyl tert.-butyl ether, methylene chloride and chloroform. The composition of a m

  1. MTBE BIOREMEDIATION WITH BIONETS CONTAINING ISOLITE, PMI, SOS ON AIR

    Science.gov (United States)

    Methyl tert-Butyl Ether (MTBE), a gasoline additive, is a persistent and foul tasting contaminant that is more mobile in ground water than BTEX. It is turning up at many American crossroads. This study's objective was to determine if biologically active in situ Bionets could bior...

  2. MTBE BIODEGRADATION IN A GRAVITY FLOW, HIGH-BIOMASS RETAINING BIOREACTOR

    Science.gov (United States)

    The aerobic biodegradation of methyl tert-butyl ether (MtBE), a widely used fuel oxygenate, was investigated using a pilot-scale biomass-retaining bioreactor called a Biomass Concentrator Reactor (BCR). The reactor was operated for a year at a flow rate of 2500 L/d on Ci...

  3. NOVEL EMBEDDED CERAMIC ELECTRODE SYSTEM TO ACTIVATE NANOSTRUCTURED TITANIUM DIOXIDE FOR DEGRADATION OF MTBE

    Science.gov (United States)

    A novel reactor combining a flame-deposited nanostructured titanium dioxide film and a set of embedded ceramic electrodes was designed, developed and tested for degradation of methyl tert-butyl ether (MTBE) in water. On applying a voltage to the ceramic electrodes, a surface coro...

  4. Bioremediation of BTEX hydrocarbons: Effect of soil inoculation with the toluenegrowing fungus Cladophialophora sp strain T1

    NARCIS (Netherlands)

    Prenafeta, F.X.; Ballerstedt, H.; Gerritse, J.; Grotenhuis, J.T.C.

    2004-01-01

    The biodegradation of a mixture of benzene, toluene, ethylbenzene, xylene, (BTEX) and methyl-tert-butyl ether (MTBE) was studied in soil microcosms. Soil inoculation with the toluene-metabolising fungusCladophialophora sp. strain T1 was evaluated in sterile and non-sterile soil. Induction of biodegr

  5. CHEMOMETRICS IN BIOANALYTICAL SAMPLE PREPARATION - A FRACTIONATED COMBINED MIXTURE AND FACTORIAL DESIGN FOR THE MODELING OF THE RECOVERY OF 5 TRICYCLIC AMINES FROM PLASMA AFTER LIQUID-LIQUID-EXTRACTION PRIOR TO HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY

    NARCIS (Netherlands)

    WIELING, J; MENSINK, CK; JONKMAN, JHG; COENEGRACHT, PMJ; DUINEVELD, CAA; DOORNBOS, DA

    1993-01-01

    A general systematic approach is described for the chemometric modelling of liquid-liquid extraction data of drugs from biological fluids. Extraction solvents were selected from Snyder's solvent selectivity triangle: methyl tert.-butyl ether, methylene chloride and chloroform. The composition of a

  6. Direct Measurement of Free Estradiol in Human Serum and Plasma by Equilibrium Dialysis-Liquid Chromatography-Tandem Mass Spectrometry.

    Science.gov (United States)

    Ray, Julie A; Kushnir, Mark M; Rockwood, Alan L; Meikle, A Wayne

    2016-01-01

    We describe a direct method of measurement of free estradiol using equilibrium dialysis followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Serum aliquots and internal standards are extracted by liquid-liquid extraction using methyl-tert-butyl ether (MTBE) followed by derivatization with dansyl chloride. An API 5500 mass spectrometer operated in positive electrospray mode is used for detection.

  7. Bioremediation of BTEX hydrocarbons: Effect of soil inoculation with the toluenegrowing fungus Cladophialophora sp strain T1

    NARCIS (Netherlands)

    Prenafeta, F.X.; Ballerstedt, H.; Gerritse, J.; Grotenhuis, J.T.C.

    2004-01-01

    The biodegradation of a mixture of benzene, toluene, ethylbenzene, xylene, (BTEX) and methyl-tert-butyl ether (MTBE) was studied in soil microcosms. Soil inoculation with the toluene-metabolising fungusCladophialophora sp. strain T1 was evaluated in sterile and non-sterile soil. Induction of

  8. Waste Water Handling Proof of Concepts at McMurdo Station, Antarctica

    Science.gov (United States)

    2014-09-17

    2-Chlorotoluene Diisopropyl ether trans-1,3-Dichloropropene 2-Hexanone Ethyl acetate Trichloroethene 4-Ethyltoluene Ethylbenzene...Trichlorofluoromethane 4-Methyl-2-pentanone Ethyl tert-butyl ether Trichlorotrifluoroethane Acetone Heptane Vinyl acetate Acetonitrile Hexachlorobutadiene Vinyl... production at the runway was limited before the start of these projects and was estimated to determine proper sizing of the two methods used. During

  9. Scientific opinion on the evaluation of substances as acceptable previous cargoes for edible fats and oils

    DEFF Research Database (Denmark)

    Petersen, Annette

    , ethyl tert-butyl ether (ETBE) and ammonium sulphate. The evaluation was based on the same criteria as those used for the evaluation of the substances currently on the list in the Annex to Commission Directive 96/3/EC as acceptable previous cargoes for edible fats and oils. Methyl acetate and ETBE meet...

  10. 75 FR 63827 - Integrated Risk Information System (IRIS); Request for Chemical Substance Nominations for 2011...

    Science.gov (United States)

    2010-10-18

    ... manganese 7439-9 methanol l67-56-1 methyl tert-butyl ether (MTBE).... 1634-04-4 mirex 2385-85-5 naphthalene...'s current chemicals management program under the Toxic Substances Control Act. PFOA and PFOS...

  11. Final Environmental Assessment for Maintaining the Rim Canal at Avon Park Air Force Range, Florida

    Science.gov (United States)

    2011-02-01

    System USACE United States Army Crop of Engineers US United States USAF...arsenic, cadmium, copper, iron, lead, manganese , selenium, silver, zinc, and mercury. Also sampled are volatile organic compounds Methyl-Tert-Butyl...private property north and west of APAFR. The greatest concentration of the general population of this tract is located at the Avon Park Correctional

  12. Les risques du travail

    CERN Document Server

    Thébaud-Mony, Annie

    2015-01-01

    Depuis les années 1990, les conditions de travail se sont peu à peu imposées dans le débat social. Néanmoins, la situation reste critique. Les risques traditionnels n'ont pas disparu : les manutentions lourdes, l'exposition professionnelle aux cancérogènes, au bruit ou aux vibrations demeurent répandues... De plus, certaines " améliorations " n'ont fait que déplacer et dissimuler les problèmes, telle l'externalisation des risques grâce à la sous-traitance. Dans le même temps, les transformations du travail et des modalités de gestion de la main-d'œuvre ont fragilisé les collectifs et accru l'isolement des salariés, conduisant à une montée visible de la souffrance psychique. Face à ces évolutions, il est plus que jamais nécessaire que tous les acteurs concernés, en particulier les salariés eux-mêmes et leurs représentants, s'approprient les connaissances indispensables pour améliorer la protection de la santé sur les lieux du travail. Tel est le but de ce livre, qui renouvelle int�...

  13. Les formes du fond

    Directory of Open Access Journals (Sweden)

    Michel Maffesoli

    2004-12-01

    Full Text Available Il n'est pas vrai que la nature a horreur du vide. Peut-être même s'y complait-elle. Le creux est aussi une modalité de l'être. Il est possible de s'y nicher, de s'y lover paresseusement et, ainsi, de se protéger contre l'angoisse du temps qui passe. Le creux des apparences est, à certains moments, une des formes d'expression de la vie sociale. Encore faut-il savoir le reconnaître. Certes, nous avons tous une existence personnelle, mais nous sommes, également, les représentants, parfois même les victimes, d'un "esprit commun", peut-être même d'un "inconscient collectif" qui s'est constitué de siècle en siècle. Et, très souvent, là où nous croyons exprimer nos propres idées, nous ne sommes que les porte-voix, les figurants d'un vaste "theatrum mundi" aux dimensions infinies.

  14. Choeur du CERN : Concert

    CERN Document Server

    CERN Choir

    2017-01-01

    Une œuvre à découvrir! La grande Missa pro defunctis de François-Joseph Gossec (1734-1829) est le chef-d’œuvre tôt venu (à vingt-cinq ans) d’un compositeur qui vivra encore 70 ans après sa création. Elle a connu la gloire, puis s’est fait un peu oublier. Pas du tout le monde cependant : des musicologues ont montré ce que le Requiem de Mozart lui devait ; et il suffit de l’avoir entendue pour comprendre pourquoi Berlioz (qui avait vingt-six ans à la mort de Gossec) en a été impressionné : les nombreux cuivres et bois répartis dans des endroits plus ou moins cachés de la salle de concert pour exprimer les frayeurs du Jugement dernier annoncent son Requiem – et celui de Verdi. Mais « plus encore que par...

  15. The glutamate receptor GluR5 agonist (S)-2-amino-3-(3-hydroxy-7,8-dihydro-6H-cyclohepta[d]isoxazol-4-yl)propionic acid and the 8-methyl analogue

    DEFF Research Database (Denmark)

    Clausen, Rasmus Prætorius; Naur, Peter; Kristensen, Anders Skov;

    2009-01-01

    GluRs). Functional characterization of 5 at cloned iGluRs using a calcium imaging assay and voltage-clamp recordings show a different activation of GluR5 compared to (S)-glutamic acid (Glu), kainic acid (KA, 1), and (S)-2-amino-3-(3-hydroxy-5-tert-butyl-4-isoxazolyl)propionic acid ((S)-ATPA, 3) as previously...

  16. Methyl gallate

    Directory of Open Access Journals (Sweden)

    Silvina Pagola

    2009-02-01

    Full Text Available The crystal structure of the title compound (systematic name: methyl 3,4,5-trihydroxybenzoate, C8H8O5, is composed of essentially planar molecules [maximum departures from the mean carbon and oxygen skeleton plane of 0.0348 (10 Å]. The H atoms of the three hydroxyl groups, which function as hydrogen-bond donors and acceptors simultaneously, are oriented in the same direction around the aromatic ring. In addition to two intramolecular hydrogen bonds, each molecule is hydrogen bonded to six others, creating a three-dimensional hydrogen-bonded network.

  17. Quality evaluation of methyl binding domain based kits for enrichment DNA-methylation sequencing.

    Directory of Open Access Journals (Sweden)

    Tim De Meyer

    Full Text Available DNA-methylation is an important epigenetic feature in health and disease. Methylated sequence capturing by Methyl Binding Domain (MBD based enrichment followed by second-generation sequencing provides the best combination of sensitivity and cost-efficiency for genome-wide DNA-methylation profiling. However, existing implementations are numerous, and quality control and optimization require expensive external validation. Therefore, this study has two aims: 1 to identify a best performing kit for MBD-based enrichment using independent validation data, and 2 to evaluate whether quality evaluation can also be performed solely based on the characteristics of the generated sequences. Five commercially available kits for MBD enrichment were combined with Illumina GAIIx sequencing for three cell lines (HCT15, DU145, PC3. Reduced representation bisulfite sequencing data (all three cell lines and publicly available Illumina Infinium BeadChip data (DU145 and PC3 were used for benchmarking. Consistent large-scale differences in yield, sensitivity and specificity between the different kits could be identified, with Diagenode's MethylCap kit as overall best performing kit under the tested conditions. This kit could also be identified with the Fragment CpG-plot, which summarizes the CpG content of the captured fragments, implying that the latter can be used as a tool to monitor data quality. In conclusion, there are major quality differences between kits for MBD-based capturing of methylated DNA, with the MethylCap kit performing best under the used settings. The Fragment CpG-plot is able to monitor data quality based on inherent sequence data characteristics, and is therefore a cost-efficient tool for experimental optimization, but also to monitor quality throughout routine applications.

  18. Jouer du piano

    Directory of Open Access Journals (Sweden)

    Fériel Kaddour

    2011-04-01

    Full Text Available La réflexion s’appuie dans un premier temps sur une opposition entre deux attitudes de pianistes  à l’égard du travail à l’instrument : Gould, qui revendique une séparation d’avec le clavier pour ne privilégier que la lecture; Arrau, dont la technique au contraire vise à « faire corps » avec son piano. L’étude de ces deux démarches d’interprètes conduit à une conclusion croisée : l’abstraction gouldienne n’est rien d’autre qu’un déplacement du jeu vers d’autres instruments (ceux qui servent à la prise de son et au montage de ses enregistrements ; le « faire-corps » hérité de la culture pianistique romantique est plus dialectique que fusionnel, et en cela implique une capacité de mise à distance. A partir de cette double conclusion, on tâche enfin de repenser la place du jeu à l’instrument dans la mise en œuvre d’une interprétation, en interrogeant le dialogue qui s’instaure entre la partition telle qu’elle s’écrit et le geste tel qu’il se joue.Our study leans on an opposition between two pianists' attitudes about their work with the instrument. Gould claims a necessary separation from the keyboard in order to prioritize reading. Arrau, on the contrary, relies on a technique which consists in “being one” with his piano. The analysis of these two interprets’ behaviours leads to a crossed conclusion: the gouldian abstraction is nothing else than a displacement of the playing towards another kind of instruments, the ones he uses in sound recording and cut up; Arrau’s “being one” is more dialectic than at first sight, and it therefore implies a real distancing from the piano. This constatation leads to rethink the place of the piano playing in the setting of an interpretation, and to highlight the real dialogue which develops itself between the score as it has been written and the gesture as it is played.

  19. Le sacre du printemps

    Directory of Open Access Journals (Sweden)

    Denise Pumain

    2002-03-01

    Full Text Available Cybergeo aura six ans en avril : dans la réalité du virtuel, dans l'univers récent et fluctuant de la publication en ligne, cela fait de nous, tout à la fois, des pionniers et des vétérans. De façon plus surprenante, il se trouve que nous sommes aussi uniques : parmi toutes les revues électroniques de sciences sociales, aucune ne combine comme Cybergeo ancienneté, publication exclusivement électronique, liberté d'accès au texte intégral, édition et gestion par des chercheurs, et comité de lec...

  20. Le Brahmane du Komintern

    Directory of Open Access Journals (Sweden)

    Elizabeth Burgos

    2008-01-01

    Full Text Available Le Brahmane du Komintern, largometraje documental del realizador francés Vladimir León, constituye un ejercicio ejemplar de investigación histórica y  de lograda factura de realización. Y, pese a no haber contado con la ayuda de ninguno organismo público, se trata de un ambicioso proyecto que cubre una amplia extensión geográfica que abarca: Estados Unidos, México, Moscú, Berlín, y la India. Gira en torno a una figura que tuvo en su tiempo su hora de gloria. Un bengalí, hijo de braman, la c...

  1. Cultures du travail

    OpenAIRE

    de Bonnault-Cornu, Phanette; Charrasse, David; Herberich-Marx, Geneviève; Lamy, Yvon; Lazier, Isabelle; Mairot, Philippe; Morel, Alain; Périssère, Michèle; Raphaël, Freddy; Ribeill, Georges; Salmeron, Pierre; Vant, André

    2015-01-01

    Qu’est-ce qu’une culture du travail ? Comment la définir autrement qu’en opposition à la culture savante ? Quelles relations une société entretient-elle avec son ou ses industries ? Comment définir et appréhender ce qu’on appelle la culture d’entreprise ? A ces questions ethnologues, sociologues, géographes et historiens apportent ici des réponses.Ce livre est aussi consacré à l’intérêt que ces sociétés, villes, petites régions, entreprises, portent à ce qui constitue leur patrimoine industri...

  2. OPERATION DU FOISONNEMENT

    Directory of Open Access Journals (Sweden)

    Gholamreza Djelveh

    2010-04-01

    Full Text Available Mousses alimentaires sont un sous-ensemble des aliments connus sous le nom de produits fouettés ou des produits aérés. Ils sont des produits formulés avec des qualités telles que la légèreté et la souplesse et sont principalement consommés à l'apéritif ou au dessert. Les produits en mousse obtenue par dispersion d'un gaz dans une matrice alimentaire (la phase continue ont connu un développement croissant au cours des années 80 et 90. Le processus d'aération liés à leurs activités de production est appelée l'expansion ou à fouetter. Le document présente les principaux-paramètres du procédé du point permanent de la formulation, la mise en œuvre processus dans les installations pilotes et à l'échelle industrielle, la caractérisation des produits finis, la base énergétique de l'échelle de processus en place, et le lien entre la formulation, émulsion préparation de l'expansion. Cette vue d'ensemble de l'opération d'expansion continue, nous a permis de mettre en évidence le fait qu'il ya des opérations de l'unité encore mal décrite par le génie des procédés et pour lesquels les méthodes et outils pour l'extrapolation et la prédiction sont encore à leurs balbutiements.

  3. Sur quelques Ichthyurus du Tonkin

    NARCIS (Netherlands)

    Gestro, R.

    1906-01-01

    Les espèces d Ichthyurus du Tonkin connues jusqu’ici étaient seulement trois: denticornis Gestro, décrite d’abord du Tenasserim (récoltes de feu Mr. L. Fea) et retrouvée ensuite dans le Haut Tonkin par S. A. R. le Prince Henri d’Orléans; Henrici Gestro, découverte par ce même explorateur, et dont le

  4. 三维电极反应器对甲基叔丁基醚降解性能的试验研究%Experiment on degradation of methyl tert-butylether by using 3D electrode reactor

    Institute of Scientific and Technical Information of China (English)

    徐苏云; 何传秋; 罗丽雯; 董亚楠; 王水寒

    2014-01-01

    Methyl tert-butyl ether ( MTBE) is a potential carcinogen pollutant.This article investigated the electrochemical degradation of MTBE in wastewater by using a novel three-dimensional electrode re-actor with granular activated carbon as particle electrode.The effects of electrolyte, voltage intensity and pH level on the degradation of MTBE were tested.Experiment results show that under the conditions of 25℃, electrolyte (Na2SO4) concentration of 0.2 mol, potential=10 V and pH=7.0, total organic car-bon ( TOC) of MTBE solution with initial concentration of 50 mmol is removed by 78% after 150 min. Compared to activated carbon adsorption and bipolar electrolysis, the three-dimensional electrode reac-tor can greatly improve the efficiency of MTBE degradation and carbonization.Therefor, the three-di-mensional electrode reactor is an effective technology to remove MTBE contamination in wastewater and has better application prospect.%甲基叔丁基醚( MTBE)是一种潜在的致癌污染物质,本文考察了以活性炭为粒子电极的三维电极反应器对水体中MTBE的降解性能。实验分别研究了电解质、电压强度和pH值对MTBE降解效果的影响。结果表明:当温度为25℃、电解质Na2 SO4浓度为0.2 mol、电压为10V、pH为7.0的条件下,初始浓度为50 mmol的MTBE溶液,在反应进行150 min后其总有机碳的去除率可达78%。与单纯活性炭吸附、两极电解对比,三维电极能大幅度提高MTBE的降解和碳化效率。因此三维电极反应器是一种能够有效去除废水中MTBE污染的技术方法,具备较好的应用前景。

  5. Le bal du loup

    CERN Multimedia

    Happy Children's Home

    2013-01-01

    The Bord'eau amateur theatre group will graciously perform a play of their creation Le bal du loup Saturday 19 October 2013 at 20:00 Sunday 20 October at 17:00 in the Théâtre des Grottes Rue Louis Favre 43, 1201 Genève Children from age 12 upwards. Summary: The new-elected mayoress of a small village would like to clean up the town by prohibiting alcohol and getting rid of its prostitutes. Then along comes « Massimo Lupo » the pimp... The performances will be given to support the Happy Children's Home charity, which runs a foster-home in Pokhara for Nepali children:  http://www.happychildrenshome.org/ Admission : minimum charge of 10 CHF per person requested, to cover the cost of technical assistance and theatre rental. Any profit will be used solely for the foster-home. At the end of each performance members of the HCH charity will be happy to answer any questions you may have. The theatre has 86 seats, thank you for reserv...

  6. Le collisionneur du futur?

    CERN Multimedia

    CERN Audiovisual Service

    2009-01-01

    Pourquoi deux études parallèles pour un même collisionneur linéaire ? Loin d’être un double effort et un gaspillage de ressources, ces deux études s’inscrivent dans une stratégie de complémentarité afin de fournir la meilleure technologie requise par la physique du futur. Vendredi 12 juin a eu lieu au CERN la première réunion conjointe CLIC et ILC. Elle n’a pas été avare de bons résultats et d’importantes décisions. Le Collisionneur Linéaire International (ILC) et le Collisionneur Linéaire Compact (CLIC) sont deux études qui font, tous deux, appel à des technologies de pointe. A première vue en compétition, les deux études sont en réalité complémentaires et elles ont un objectif commun : proposer dans les plus brefs délais et au moindre coût, l‘accélérateur linéaire le mieux adapté pour prendre le relais de la physique des très hautes énergies après le LHC.

  7. Effets du fluor et du phosphogypse chez les organismes marins

    OpenAIRE

    Martin, J.L.; Le Guellec, Anne-marie; Cosson, R.

    1982-01-01

    Dans le cadre général des recherches visant à déterminer l'action des effluents industriels et plus précisément du fluor dans le cas de cette étude, le programme dont les résultats sont présentés avait pour but de déterminer les effets de cet élément sur les organismes marins. Trois aspects essentiels ont été envisagés : - Effets létaux du fluor ; - effets du fluor sur certaines fonctions éthologiques ; - bio-accumulation de l'élément par les organismes marins.

  8. Main: 1DU5 [RPSD[Archive

    Lifescience Database Archive (English)

    Full Text Available 1DU5 トウモロコシ Corn Zea mays L. Zeamatin Precursor. Name=Zlp; Zea Mays Molecule: Zeama...NNACPVFKKDEYCCVGSAANDCHPTNYSRYFKGQCPDAYSYPKDDATSTFTCPAGTNYKVVFCP corn_1DU5.jpg ...

  9. DuPontTM OmneraTM LQMTM (DPX-SGE27 – A new generation of liquid formulated cereal herbicides

    Directory of Open Access Journals (Sweden)

    Uhl, Thomas

    2016-02-01

    Full Text Available DuPontTM OmneraTM LQMTM (DPX-SGE27 (5 g/l metsulfuron-methyl, 30 g/l thifensulfuron-methyl, 135 g/l fluroxypyr represents with an application rate of 1 l/ha a new “herbicide” solution in cereals. DuPontTM OmneraTM LQMTM is characterized by a very good efficacy, a broad weed spectrum, a broad application window (BBCH 20 – 39 in winter cereals; BBCH 12 – 39 in spring cereals and a very good crop safety. DuPontTM OmneraTM LQMTM is formulated as oil dispersion. Several years of field trials demonstrate the efficacy of DuPontTM OmneraTM LQMTM against mayweed (Matricaria chamomilla, oilseed rape (Brassica napus, common chickweed (Stellaria media, but also against difficult weeds like wild buckwheat (Polygonum convolvulus and especially against catchweed bedstraw (Galium aparine.

  10. A convenient method to generate methylated and un-methylated control DNA in methylation studies

    Directory of Open Access Journals (Sweden)

    Mehdi Manoochehri

    2013-09-01

    Full Text Available Methylated and un-methylated control DNA is an important part of DNA methylation studies. Although human and mouse DNA methylation control sets are commercially available, in case of methylation studies on other species such as animals, plants, and bacteria, control sets need to be prepared. In this paper a simple method of generating methylated and un-methylated control DNA is described. Whole genome amplification and enzymatic methylation were performed to generate un-methylated and methylated DNA. The generated DNA were confirmed using methylation sensitive/dependant enzymes, and methylation specific PCR. Control reaction assays confirmed the generated methylated and un-methylated DNA.

  11. Gestion durable du paysage

    Directory of Open Access Journals (Sweden)

    Jean-David Gerber

    2009-03-01

    Full Text Available Le paysage est de plus en plus perçu comme une ressource. À ce titre, il est nécessaire de trouver des instruments juridiques, politiques ou économiques susceptibles de gérer cette « ressource-paysage » sur le long terme. Le gouvernement suisse a introduit récemment l’instrument des parcs naturels régionaux, organisés selon le modèle français, dans sa législation de protection de la nature et du paysage. Une mise en regard des nouveaux parcs avec des structures de gestion beaucoup plus anciennes, les bourgeoisies et les corporations, permet de mettre en évidence les forces et les faiblesses de chacun de ces instruments dans leur contribution à résoudre les rivalités d’usage entre acteurs utilisant ou influençant la ressource paysage. Cette comparaison permet de formuler des recommandations pratiques concernant la gestion de cette ressource.The landscape is increasingly perceived as a resource. For this reason, it is necessary to find legal, political and economic instruments that will succeed in managing this “resource landscape” in the long term. The Swiss government recently introduced the instrument of regional nature parks into the legislation governing nature and landscape preservation; the proposed parks are organized on the basis of the French model. The examination of the new parks from the perspective of much older management structures, i.e. the civic municipalities (bourgeoisies and corporations, makes it possible to demonstrate the strengths and weaknesses of each of these instruments in their contribution to the resolution of use rivalries between actors who use or influence the resource landscape. This comparison also enables the formulation of practical recommendations regarding the management of this resource.

  12. Cri du Chat syndrome

    Directory of Open Access Journals (Sweden)

    Cerruti Mainardi Paola

    2006-09-01

    Full Text Available Abstract The Cri du Chat syndrome (CdCS is a genetic disease resulting from a deletion of variable size occurring on the short arm of chromosome 5 (5p-. The incidence ranges from 1:15,000 to 1:50,000 live-born infants. The main clinical features are a high-pitched monochromatic cry, microcephaly, broad nasal bridge, epicanthal folds, micrognathia, abnormal dermatoglyphics, and severe psychomotor and mental retardation. Malformations, although not very frequent, may be present: cardiac, neurological and renal abnormalities, preauricular tags, syndactyly, hypospadias, and cryptorchidism. Molecular cytogenetic analysis has allowed a cytogenetic and phenotypic map of 5p to be defined, even if results from the studies reported up to now are not completely in agreement. Genotype-phenotype correlation studies showed a clinical and cytogenetic variability. The identification of phenotypic subsets associated with a specific size and type of deletion is of diagnostic and prognostic relevance. Specific growth and psychomotor development charts have been established. Two genes, Semaphorin F (SEMAF and δ-catenin (CTNND2, which have been mapped to the "critical regions", are potentially involved in cerebral development and their deletion may be associated with mental retardation in CdCS patients. Deletion of the telomerase reverse transcriptase (hTERT gene, localised to 5p15.33, could contribute to the phenotypic changes in CdCS. The critical regions were recently refined by using array comparative genomic hybridisation. The cat-like cry critical region was further narrowed using quantitative polymerase chain reaction (PCR and three candidate genes were characterised in this region. The diagnosis is based on typical clinical manifestations. Karyotype analysis and, in doubtful cases, FISH analysis will confirm the diagnosis. There is no specific therapy for CdCS but early rehabilitative and educational interventions improve the prognosis and considerable

  13. Les paradoxes du littoral Swahili

    Directory of Open Access Journals (Sweden)

    François Bart

    2008-10-01

    Full Text Available Le contact entre l'océan Indien occidental et le continent africain a forgé l'identité et l'originalité du littoral swahili. Cette interface, longue d'environ 2 000 kilomètres, du sud de la Somalie au nord du Mozambique, constitue un monde original où, au gré de traditions anciennes de circulation maritime et continentale se sont diffusées et mêlées des influences culturelles venues du continent africain, de la péninsule arabique et de la péninsule indienne. Le développement du continent, du littoral et des archipels s'inscrit dans une double logique de fragmentation et d'ouverture au monde. Dans cette vaste aire géographique, le rôle de relais des îles et des axes de pénétration continentale à partir des ports est essentiel.The identity and the original features of the Swahili seashore mainly proceed from the contact of African mainland and western indian Ocean. This coastal interface, stretching over 2 000 kilometres from southern Somalia to northern Mozambique, is characterized by ancient traditions of trade movements through maritime areas and mainland as well, which spread and mixed different cultural influences originating from Africa and both Arabic and Indian peninsulas. The development of this area is linked to both fragmentation and opening dynamics. In such a wide area, the relaying function of islands and continental corridors from main harbours is very important.

  14. ETUDE GEOCHIMIQUE ET ISOTOPIQUE DES EAUX SUPERFICIELLES DU BASSIN VERSANT DU FURAN ET DES EAUX MINERALES DU GRABEN DU FOREZ, EST DU MASSIF CENTRAL FRANÇAIS

    OpenAIRE

    Gal, Frédérick

    2005-01-01

    Ce travail est basé sur l'étude d'un continuum eau de pluie – eau de surface – eau minérale, en utilisant différents outils chimiques et géochimiques. La zone d'étude se situe en bordure Est du Massif Central Français. Elle comprend des entités géographiques et géologiques variées (complexe granito-gneissique et cristallophyllien – Monts du Forez et du Lyonnais d'âge hercynien, graben Oligocène du Forez à venues volcaniques miocènes).La première partie repose sur l'étude en isotopes stables (...

  15. (E-tert-Butyl 2-(5-{[4-(dimethylaminophenyl]diazenyl}-2,6-dioxo-1H-pyrimidin-3-ylacetate dichloromethane monosolvate

    Directory of Open Access Journals (Sweden)

    Robert H. E. Hudson

    2014-05-01

    Full Text Available In the title compound, C18H23N5O4·CH2Cl2, the dichloromethane solvent molecule is disordered over two sets of sites in a 0.630 (13:0.370 (13 ratio. The dihedral angle between the uracil and phenyl rings is 30.2 (1°. In the crystal, the principal interactions are N—H...O hydrogen bonds, which link uracil units across centres of symmetry, forming eight-membered rings with an R22(8 graph-set motif. The structure also displays C—H...O and C—H...Cl hydrogen bonds. Intramolecular C—H...O short contacts are also observed.

  16. 6-tert-Butyl-4-[(4-hydroxymethyl-2H-1,2,3-triazol-2-ylmethyl]-2H-chromen-2-one

    Directory of Open Access Journals (Sweden)

    Nasseem El-Khatatneh

    2016-10-01

    Full Text Available In the title compound, C17H19N3O3, the triazole ring and the chromene ring system [maximum deviation = 0.018 (2 Å for the O atom] bridged via a methylene C atom, are inclined to one another by 73.2 (1°. In the crystal, molecules are linked by O—H...N hydrogen bonds, forming zigzag chains along [001]. The chains are linked by C—H...O hydrogen bonds, forming layers parallel to (010, and these layers are linked by C—H...π and π–π interactions [intercentroid distance = 3.557 (1 Å], forming a three-dimensional newwork. The hydroxymethyl group at the 4-position of the triazole ring is disordered over two sets of sites, with a refined occupancy ratio of 0.418 (11:0.584 (11.

  17. Synthesis of p-tert-butyl Mandelic Acid by Phase Transfer Catalysis%相转移催化法合成对叔丁基扁桃酸

    Institute of Scientific and Technical Information of China (English)

    何佺; 彭阳峰

    2003-01-01

    以对叔丁基苯甲醛为原料,TEBA(苄基氯三乙胺)为催化剂相转移催化法合成对叔丁基扁桃酸.其合成工艺参数:温度60±2℃,反应时间12h,n(对叔丁基扁桃酸):n(三氯甲烷)=1:2~3,相转移催化剂TEBA的用量5~10g/mol对叔丁基苯甲醛.经过核磁共振、红外和元素分析对其结构进行了分析和确认.产品质量分数99.1%,收率51.7%.

  18. (6S-2-tert-Butyl-6-[(4S,5R-3,4-dimethyl-5-phenyloxazolidin-2-yl]phenol

    Directory of Open Access Journals (Sweden)

    Alexander E. Anderson

    2010-04-01

    Full Text Available The title compound, C21H27NO2, exhibits hydrogen bonding between the phenolic H atom and the heterocyclic N atom. The absolute configuration of the molecule is known from the synthetic procedure.

  19. Synthesis, Physical Characterization of M(III Transition Metal Complexes Derived from Thiodihydrazide and 5-tert-Butyl-2-hydroxy-3-(3-phenylpent-3-yl Benzaldehyde

    Directory of Open Access Journals (Sweden)

    Gajendra Kumar

    2012-01-01

    Full Text Available A Schiff base ligand was synthesized by reacting 5-tert-butl-2-hydroxy-3-(3-phenylpent-3-yl benzaldehyde and thiodihydrazide (2:1 and a series of metal complexes with this new ligand were synthesized by reaction with Cr (III, Mn (III, and Fe (III metal salt in methanolic medium. The Schiff base ligand and its complexes have been characterized with the help of elemental analysis, conductance measurements, magnetic measurements and their structure configuration have been determined by various spectroscopic (electronic, IR, 1H NMR, 13C NMR, GCMS techniques. Electronic and magnetic moments of the complexes indicate that the geometries of the metal centers were octahedral. IR spectral data suggest that ligand behaves as a tetradentate ligand with ONNO donor sequence towards the metal ion.

  20. Crystal structure of 1,3-bis(3-tert-butyl-2-hydroxy-5-methylbenzyl-1,3-diazinan-5-ol monohydrate

    Directory of Open Access Journals (Sweden)

    Augusto Rivera

    2016-09-01

    Full Text Available In the title hydrate, C28H42N2O3·H2O, the central 1,3-diazinan-5-ol ring adopts a chair conformation with the two benzyl substituents equatorial and the lone pairs of the N atoms axial. The dihedral angle between the aromatic rings is 19.68 (38°. There are two intramolecular O—H...N hydrogen bonds, each generating an S(6 ring motif. In the crystal, classical O—H...O hydrogen bonds connect the 1,3-diazinane and water molecules into columns extending along the b axis. The crystal structure was refined as a two-component twin with a fractional contribution to the minor domain of 0.0922 (18.

  1. Crystal structure of bis{2,4-di-tert-butyl-6-[(isopropyliminomethyl]phenolato-κ2N,O}zinc dichloromethane monosolvate

    Directory of Open Access Journals (Sweden)

    Yuan-Zeng Hao

    2014-12-01

    Full Text Available In the title compound, [Zn(C18H28NO2]·CH2Cl2, the ZnII atom is N,O-chelated by two crystallographically independent salicylaldehyde imine ligands, leading to a distorted tetrahedral coordination sphere. The dihedral angle between the planes of the two metallacycles is 88.69 (6°. Intramolecular non-classical C—H...O hydrogen-bonding interactions are observed. In the crystal, the complex molecules stack into columns along the a axis. Dichloromethane solvent molecules are situated in the voids of this arrangement.

  2. Bis{μ-4,4′,6,6′-tetra-tert-butyl-2,2′-[N-(2-oxidoethyliminodimethylene]diphenolato}dialuminium(III

    Directory of Open Access Journals (Sweden)

    Stephanie L. Hemmingson

    2010-08-01

    Full Text Available The title compound, [Al2(C32H48NO32], exists as a dimer with bridging ethoxide groups. It was isolated from a reaction mixture of the parent ligand and trimethylaluminium in tetrahydrofuran. The geometry around the AlIII atom is a slightly distorted trigonal-bipyramid, typical of atrane derivatives.

  3. 5-tert-Butyl 3-ethyl 1-isopropyl-4,5,6,7-tetrahydro-1H-pyrazolo[4,3-c]pyridine-3,5-dicarboxylate

    Directory of Open Access Journals (Sweden)

    Huan-Mei Guo

    2011-12-01

    Full Text Available In the title compound, C17H27N3O4, the six-membered ring adopts a half-chair conformation with the N atom and the adjacent methylene C atom displaced by −0.391 (2 and 0.358 (2 Å, respectively, from the plane of the other four atoms. In the crystal, molecules are linked by weak C—H...O interactions.

  4. 乙基叔丁基醚合成研究进展%Research advances in the synthesis of ethyl-tert butyl ether

    Institute of Scientific and Technical Information of China (English)

    谢小莉; 张睿; 段超; 齐小峰; 王红梅; 潘蕊娟; 黄彦琦

    2015-01-01

    Ethyl tert-bUtyl ether(ETBE)has high octane nUmber and is a kind of environmental friendly gasoline additive. The reaction mechanisms for ETBE synthesis on the sUrfaces of different catalysts were introdUced. The research statUs of the catalysts for ETBE synthesis at home and abroad,and some typical prodUction technologies of ETBE synthesis overseas were reviewed. The catalytic activity,stability and selectivity of different catalysts were compared. It was pointed oUt that it was an important research direction to improve the thermal stability of resin catalysts by modification in this field. So far,the matUre prodUction technology of ETBE has been obtained abroad,and it has been still in research stage domestically. It is necessary to speed Up its research and development and complete indUstrialization domestically.%乙基叔丁基醚具有较高的辛烷值,是一种环境友好的汽油添加剂。介绍乙基叔丁基醚在不同催化剂上合成的反应机理,综述国内外合成乙基叔丁基醚的催化剂研究现状及国外几种典型的乙基叔丁基醚生产工艺流程。比较不同催化剂的催化活性、稳定性和选择性。指出通过改性提高树脂催化剂的热稳定性是该领域重要的研究方向。国外已拥有成熟的乙基叔丁基醚合成技术,国内大部分还处于研究阶段,应尽快加强技术开发,早日实现产业化。

  5. Production of Ethyl Tert-Butyl Ether Using Low-Grade Ethanol%低浓度乙醇制乙基叔丁基醚

    Institute of Scientific and Technical Information of China (English)

    杨伯伦; 杨三八

    2000-01-01

    研究了以叔丁醇及低浓度乙醇为原料,用催化精馏技术制乙基叔丁基醚(ETBE)的工艺.比较了两种酸式盐的催化效果.试验结果表明,在同样操作条件下,硫酸氢钾的催化效果优于硫酸氢钠;乙醇一次加入、叔丁醇连续加入可有效抑制叔丁醇分解的副反应,从而提高产物中ETBE的浓度.

  6. Tert-butyl 3-oxo-2,3,4,5,6,7-hexahydro-1H-pyrazolo[4,3-c]pyridine-5-carboxylate

    Directory of Open Access Journals (Sweden)

    Tara Shahani

    2010-01-01

    Full Text Available In the title compound, C11H17N3O3, the pyrazole ring is approximately planar, with a maximum deviation of 0.005 (2 Å, and forms a dihedral angle of 5.69 (13° with the plane through the six atoms of the piperidine ring. In the crystal, pairs of intermolecular N—H...O hydrogen bonds form dimers with neighbouring molecules, generating R22(8 ring motifs. These dimers are further linked into two-dimensional arrays parallel to the bc plane by intermolecular N—H...O and C—H...O hydrogen bonds.

  7. Réflexion sur l’origine du processus de segmentation du marche du travail

    Directory of Open Access Journals (Sweden)

    Attia Nicole

    2006-01-01

    Full Text Available (francuski Ce travail propose une réflexion sur l'origine du processus de segmentation du marché du travail par rapport à l'entreprise. Se situe-t-elle au sein même de l'entreprise ou en amont, c'est à dire entre les entreprises? Cela revient à se demander si on peut avoir une approche microéconomique ou macroéconomique de la segmentation et, à s'interroger sur le rôle réel tenu par les firmes dans le processus. Déterminant pour la théorie, ce rôle est à repenser selon la réponse apportée à notre question.

  8. Photodecomposition of an acaricide, fenazaquin, in aqueous alcoholic solution.

    Science.gov (United States)

    Bhattacharyya, Jayati; Banerjee, Hemanta; Bhattacharyya, Anjan

    2003-07-02

    Fenazaquin (I) is a new acaricide of the quinazoline class. The photodecomposition of I was studied in aqueous methanolic and 2-propanolic solution under UV light (30 h) and sunlight (70 h) separately. The photolytic half-lives in aqueous methanolic solution were found to be 17.1 h (UV) and 38.1 h (sunlight), whereas these were 12.9 h (UV) and 29.2 h (sunlight) for aqueous 2-propanolic solution; all followed a first-order reaction kinetics. Six photoproducts were obtained: beta-phenyl (p-tert-butyl) ethyl alcohol (II), 4-hydroxyquinazoline (III), p-tert-butyl vinyl benzene (IV), 2,4-dihydroxyquinazoline (V), phenyl (p-tert-butyl) acetic acid (VI), and 2-methyl-2-[4'-(2' '-hydroxyethyl)phenyl]propanoic acid (VII). Compounds VI and VII could be isolated only from aqueous 2-propanolic solution under sunlight irradiation. The major degradation products are formed as a result of cleavage of the ether bridge linking the quinazoline and phenyl ring systems of the molecule, oxidation of the tert-butyl substituent, and oxidation of the heterocyclic portion of the quinazoline ring. A probable mechanism of formation of the photoproducts is also suggested.

  9. Cri-du-chat syndrome

    NARCIS (Netherlands)

    Didden, H.C.M.; Curfs, L.M.G

    2013-01-01

    Cri-du-chat syndrome is a genetic disease resulting from a deletion occurring on the short arm of chromosome 5 (5p-). The incidence ranges from 1:15 000 to 1:50 000 live-born infants. Its main clinical features are a high-pitched monochromatic cry, microcephaly, broad nasal bridge, epicanthal folds,

  10. Caractérisation des sables et morphologie du fond du lac du ...

    African Journals Online (AJOL)

    Administrateur

    Map of this lake 26 years after its setting in water. Key words : Dam .... La méthode d'interpolation retenue est l'IDW (Inverse Distance Weighting) avec un pas .... Figure 2 : Répartition des faciès de surface des sédiments du lac de Taabo. 3.3.

  11. LES GITES PLOMBO-ZINCIFERES DU DISTRICT MINIER DU KOUDIAT SIDU AUSUD DU KEF EN TUNISIE

    Directory of Open Access Journals (Sweden)

    Ivan Jurković

    1992-12-01

    Full Text Available Les auteurs ont dćcrit l:i stratigiaphie. I.i tectonique, le corps de minerals, la paragenese et la genese dcs gttes Koudiat Sidri situ&s environ 20 km au sud de la ville du Kef en Tunisie.

  12. Dissociation dynamics of methylal

    Energy Technology Data Exchange (ETDEWEB)

    Beaud, P.; Frey, H.-M.; Gerber, T.; Mischler, B.; Radi, P.P.; Tzannis, A.-P. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1999-08-01

    The dissociation of methylal is investigated using mass spectrometry, combined with a pyrolytic radical source and femtosecond pump probe experiments. Based on preliminary results two reaction paths of methylal dissociation are proposed and discussed. (author) 4 fig., 3 refs.

  13. Le parcours migratoire de jeunes ruraux du bled du kif

    Directory of Open Access Journals (Sweden)

    Khalid Mouna

    2015-06-01

    Full Text Available Cet article analyse le parcours migratoire des jeunes ruraux originaires des zones de production du cannabis, jeunes qui cherchent à briser les chaînes de soumission et d’humiliation vécues au quotidien. Pour les jeunes concernés par notre étude, la migration constitue un moyen de s’intégrer dans des réseaux transnationaux et ainsi d’entamer une carrière de beznass (commerçant du cannabis. Ce parcours « initiatique » permet à ces jeunes de revenir au bled avec de nouvelles idées, des moyens accrus, et de jouer un rôle actif dans l’économie locale – qui reste pour eux focalisée sur la production de cannabis, cette dernière restant néanmoins officiellement interdite.

  14. Paul Celan in Translation: "Du sei wie du"

    Directory of Open Access Journals (Sweden)

    John Felstiner

    1983-09-01

    Full Text Available Translating the lyric poetry of Paul Celan, especially his later poems, carries not only the endemic challenge and difficulty of any verse translation, but the added incentive of doing justice to a writer whose whole recourse after the Holocaust—whose sanctuary, if he was to have any at all—he sought in language itself, specifically in the Muttersprache , the mother tongue that was as well the tongue of those who murdered his mother and father. This essay exposes a process of translating "Du sei wie du" (1970, which perhaps more than any other poem by Celan, at once solicits and defies translation, moving as it does from modern to medieval German, and closing with Hebrew words from Isaiah— a messianic imperative that shows Celan verging as ever on his Jewish identity.

  15. Dynamique narrative du texte, du film et de la musique

    OpenAIRE

    Wildgen, Wolfgang

    2015-01-01

    La narrativité est foncièrement liée à la dynamique des événements et des actions représentés, et elle dépend du champ pragmatique narrateur/récepteur, c’est-à-dire du discours narratif. Cette dynamique demande une théorisation adéquate, par exemple au sein de la théorie des systèmes dynamiques ou de l’analyse vectorielle, et elle se manifeste dans des modalités différentes. Nous présentons des exemples d’analyse dans la modalité linguistique (récit oral spontané, conte populaire), dans la mo...

  16. Genome-wide DNA methylation modified by soy phytoestrogens: role for epigenetic therapeutics in prostate cancer?

    Science.gov (United States)

    Karsli-Ceppioglu, Seher; Ngollo, Marjolaine; Adjakly, Mawussi; Dagdemir, Aslihan; Judes, Gaëlle; Lebert, André; Boiteux, Jean-Paul; Penault-LLorca, Frédérique; Bignon, Yves-Jean; Guy, Laurent; Bernard-Gallon, Dominique

    2015-04-01

    In prostate cancer, DNA methylation is significantly associated with tumor initiation, progression, and metastasis. Previous studies have suggested that soy phytoestrogens might regulate DNA methylation at individual candidate gene loci and that they play a crucial role as potential therapeutic agents for prostate cancer. The purpose of our study was to examine the modulation effects of phytoestrogens on a genome-wide scale in regards to DNA methylation in prostate cancer. Prostate cancer cell lines DU-145 and LNCaP were treated with 40 μM of genistein and 110 μM of daidzein. DNMT inhibitor 5-azacytidine (2 μM) and the methylating agent budesonide (2 μM) were used to compare their demethylation/methylation effects with phytoestrogens. The regulatory effects of phytoestrogens on DNA methylation were analyzed by using a methyl-DNA immunoprecipitation method coupled with Human DNA Methylation Microarrays (MeDIP-chip). We observed that the methylation profiles of 58 genes were altered by genistein and daidzein treatments in DU-145 and LNCaP prostate cancer cells. In addition, the methylation frequencies of the MAD1L1, TRAF7, KDM4B, and hTERT genes were remarkably modified by genistein treatment. Our results suggest that the modulation effects of phytoestrogens on DNA methylation essentially lead to inhibition of cell growth and induction of apoptosis. Genome-wide methylation profiling reported here suggests that epigenetic regulation mechanisms and, by extension, epigenetics-driven novel therapeutic candidates warrant further consideration in future "omics" studies of prostate cancer.

  17. Feeding stimulants eliciting the probing behavior for Peregrinator blannulipes Montrouzier et Signore (Hemiptera: Ruduviidae) from Tribolium confusum (Jacquelin du Val).

    Science.gov (United States)

    Tebayashi, Shin-ichi; Kawahara, Takuya; Kim, Chul-Sa; Nishi, Akinori; Takahashi, Keiichi; Miyanoshita, Akihiro; Horiike, Michiro

    2003-01-01

    Four fatty acid methyl esters identified in the solvent extract of Tribolium confusum (Jacquelin du Val) larvae as kairomones were individually and collectively tested for probing behavior of Peregrinator biannulipes Montrouzier et Signoret. All identified fatty acid methyl eaters, methyl palmitate, methyl linolate, methyl oleate and methyl stearate, exhibited characterisitic kairomonal probing behavior of P. biannulipe toward the lure. These fatty acid methyl ester were active at 0.2 microg/lure but a synergistic effect was not observed among them. Commercially available C8-C14 even-numbered fatty acid methyl esters that were not detected in the extract of T. confusum larvae also elicited a probing behavior but their activities were weaker than those of four fatty acid methyl ester (C16:0, C18:0, C18:1 and C18:2) identified in the extract. On the other hand, C17 and C19 odd-numbered fatty acid methyl esters did not show any activity at all.

  18. L’Harmonie du monde

    Directory of Open Access Journals (Sweden)

    Martine Clouzot

    2003-11-01

    Full Text Available La Bourgogne est particulièrement bien présente et représentée dans l’exposition sur la musique et ses représentations au Moyen Âge organisée par Isabelle Marchesin (université de Poitiers, Christine Laloue (conservatrice du Patrimoine au Musée et Martine Clouzot (université de Bourgogne, au Musée de la Musique à Paris du 26 mars au 27 juin 2004. En Côte-d’Or, à Dijon, la Bibliothèque municipale a donné son accord officiel pour le prêt de la Bible d’Etienne Harding, les Moralia in Job et u...

  19. L'energie du moustique

    CERN Document Server

    Augereau, J F

    2002-01-01

    ENSEMBLE DE QUATRE ARTICLES - LARGE HADRON COLLIDER: Le dernier accelerateur de particules du CERN, le LEP, produisait des faisceaux d'electrons de 100 GeV chacun. Le LHC, qui accelere des faisceaux de protons, leur communiquera une energie de 7 TeV chacun. Une energie a la fois colossale et derisoire. Un TeV represente a peu pres l'energie cinetique d'un moustique (1/2 page).

  20. Revision du Genre Aseraggodes Kaup

    NARCIS (Netherlands)

    Chabanaud, P.

    1930-01-01

    Le présent travail comprend la définition du genre Aseraggodes Kaup et la revision, sous forme d'une clef dichotomique, de toutes les espèces qui le composent, revision établie d'après les types eux-mêmes de ces espèces. Ce genre Aseraggodes appartient à la famille des Soleidae et à la sousfamille

  1. Collecting uncollectables: Joachim Du Bellay

    Directory of Open Access Journals (Sweden)

    Gro Bjørnerud Mo

    2017-09-01

    Full Text Available Lists of wonders have circulated for millennia. Over and over, such inventories of spectacular man made constructions have been rewritten, re-edited and reimagi-ned. Both the wonders and the lists of wonders, preferably of the seven, have had a profound and long-lasting effect, and have been abundantly imitated, copied and reworked. Renaissance creative thinking was obsessed with the seven wonders of the ancient world, and early-modern Europe experienced a surge of visual and verbal depictions of wonders. This article is about a remarkable list of seven wonders, included in one of Joachim Du Bellay's canonical poems on Roman antiquities (Antiquités de Rome, published in Paris in 1558. Du Bellay shapes his list of wonders by exploring pat-terns of both repetition and mutability. Almost imperceptibly, he starts suggesting connections between 16th-century Rome and distant civilizations. Through the eyes of a fictive traveller and collector, the poet venerates the greatness and la-ments the loss of ancient buildings, sites and works of art, slowly developing a ver-bal, visual and open-ended gallery, creating a collection of crumbling or vanished, mainly Roman, architecture. This poetic display of ruins and dust in the Eternal City is nourished by the attraction of the inevitable destruction of past splendour and beauty. In the sonnets, Du Bellay imitates classical models and patterns. Whi-le compiling powerful images and stories of destruction, he combines techniques associated with both a modern concept of copy and more ancient theories of co-pia. In this context, this article also explores whether Pliny's Natural History might be a source for the imaginary collection of lost sites and wonders in Du Bellay's Antiquit's.

  2. Enrichment of methylated DNA by methyl-CpG immunoprecipitation.

    Science.gov (United States)

    Sonnet, Miriam; Baer, Constance; Rehli, Michael; Weichenhan, Dieter; Plass, Christoph

    2013-01-01

    Normal DNA methylation is an epigenetic modification required for proper development. Aberrant DNA methylation, in contrast, is frequently observed in many different malignancies including leukemias and lymphomas. Global DNA methylation profiling addresses the methylated sequences (methylome) of patient genomes to identify disease-specific methylation patterns. Workload in methylome analyses can be considerably reduced by methylome enrichment using proteins or antibodies with high affinity to methylated DNA. Methyl-CpG Immunoprecipitation (MCIp) employs an immobilized recombinant human methyl-CpG binding domain protein 2, MBD2, which binds methylated CpGs in double-stranded DNA. Elution with increasing salt concentrations allows the fractionated enrichment of different degrees of methylation.

  3. Prairie du Chien: A Historical Study,

    Science.gov (United States)

    1976-10-01

    Naudouwessee with whom this governor made peace and introduced trade and commerce among the whole nation. His son the successor told me that some of the...Nicholas Perrot, French Commandant of the West, with a party of couriers du bois and voyageurs descended the Wisconsin River and erected Fort St...number of traders and voyageurs settled at Prairie du Chien. Thomas Anderson who settled at Prairie du Chien in 1800 described the conditions on his

  4. Genetics Home Reference: cri-du-chat syndrome

    Science.gov (United States)

    ... Health Conditions cri-du-chat syndrome cri-du-chat syndrome Enable Javascript to view the expand/collapse ... PDF Open All Close All Description Cri-du-chat (cat's cry) syndrome, also known as 5p- (5p ...

  5. N-(3-{[(Z-(3-Hydroxy-4-methylphenylimino]methyl}pyridin-2-ylpivalamide

    Directory of Open Access Journals (Sweden)

    Şehriman Atalay

    2016-03-01

    Full Text Available The molecular structure of the title compound, C18H21N3O2, contains pivalamide, pyridin and hydroxy-methylphenyl moieties. The whole molecule is not planar, the dihedral angle between the benzene rings being 34.84 (7°. The molecular conformation is stabilized by an intramolecular N—H...N hydrogen bond. In the crystal, molecules are linked by O—H...O, O—H...N and C—H...O hydrogen bonds. The C and H atoms of the tert-butyl group disordered over two sets of sites with an occupancy ratio of 0.692 (5:0.308 (5.

  6. Au fil du temps (1976 ou la loi du seuil

    Directory of Open Access Journals (Sweden)

    Isabelle Singer

    2010-04-01

    Full Text Available Ayant choisi de vivre dans un camion, les héros d’Au fil du temps (film de Wim Wenders de 1976 font du seuil une expérience particulière. Celle de la rupture avec toute idée de foyer et celle du refus d’appartenance à la terre natale, cette terre allemande traversée par une frontière le long de laquelle ils vont voyager, et qui les renvoie à chaque instant aux traumatismes de l’Histoire. Sur le pare-brise du camion, l’extérieur (campagnes indifférenciées, villes à l’abandon… et l’intérieur se superposent. Au fil du temps questionne le paysage : il s’agit d’en décoller un à un les mythes qui le recouvrent. L’image alors n’est plus surface mais volume à traverser, à lacérer et découvrir ce qui est tissé dans le paysage. La démarche de Wenders est alors proche de celle d’un de ses contemporains : Anselm Kiefer. Le paysage allemand provoque le rejet parce qu’il y a là toujours plus que le visible : des strates et des strates de culpabilité que le mythe - et c’est sa fonction - a recouvert. Et qu’il s’agira ici, de soulever. Le choix du nomadisme, c’est celui d’un état de l’humanité antérieur à l’idée de patrie. Et c’est aussi celui de la solitude, comme prix à payer à ce refus d’appartenance et à cette mise à jour des mythes. L’appartenance à la terre allemande et à son Histoire est profondément problématique parce que les pères sont fondamentalement coupables. On se reconnaîtra alors des pères de substitution : des pères de cinéma (Nicholas Ray ou Fritz Lang. Et l’on substituera l’Histoire du cinéma à l’Histoire. Bruno est réparateur ambulant de projecteurs et Au fil du temps dressera, au gré de ses pérégrinations, un état des lieux du cinéma allemand des années soixante-dix : déliquescent, colonisé par les images hollywoodiennes. Il faut que cela change : état du cinéma ; état des protagonistes solitaires en quête d’une identit

  7. Regulation of DU145 prostate cancer cell growth by Scm-like with four mbt domains 2

    Indian Academy of Sciences (India)

    Kwanghyun Lee; Wonho Na; Je-Heon Maeng; Hongjin Wu; Bong-Gun Ju

    2013-03-01

    Mammalian SFMBTs have been considered to be polycomb group repressors. However, molecular mechanisms underlying mammalian SFMBTs-mediated gene regulation and their biological function have not been characterized. In the present study, we identified YY1 and methylated histones as interacting proteins of human SFMBT2. We also found that human SFMBT2 binds preferentially to methylated histone H3 and H4 that are associated with transcriptional repression. Using DU145 prostate cancer cells as a model, we showed that SFMBT2 has a transcriptional repression activity on HOXB13 gene expression. In addition, occupancy of SFMBT2 coincided with enrichment of diand tri-methylated H3K9 and H4K20 as well as tri-methylated H3K27 at the HOXB13 gene promoter. When SFMBT2 was depleted by siRNA in DU145 prostate cancer cells, significant up-regulation of HOXB13 gene expression and decreased cell growth were observed. Collectively, our findings indicate that human SFMBT2 may regulate cell growth via epigenetic regulation of HOXB13 gene expression in DU145 prostate cancer cells.

  8. Regulation of DU145 prostate cancer cell growth by Scm-like with four mbt domains 2.

    Science.gov (United States)

    Lee, Kwanghyun; Na, Wonho; Maeng, Je-Heon; Wu, Hongjin; Ju, Bong-Gun

    2013-03-01

    Mammalian SFMBTs have been considered to be polycomb group repressors. However, molecular mechanisms underlying mammalian SFMBTs-mediated gene regulation and their biological function have not been characterized. In the present study, we identified YY1 and methylated histones as interacting proteins of human SFMBT2. We also found that human SFMBT2 binds preferentially to methylated histone H3 and H4 that are associated with transcriptional repression. Using DU145 prostate cancer cells as a model, we showed that SFMBT2 has a transcriptional repression activity on HOXB13 gene expression. In addition, occupancy of SFMBT2 coincided with enrichment of diand tri-methylated H3K9 and H4K20 as well as tri-methylated H3K27 at the HOXB13 gene promoter. When SFMBT2 was depleted by siRNA in DU145 prostate cancer cells, significant up-regulation of HOXB13 gene expression and decreased cell growth were observed. Collectively, our findings indicate that human SFMBT2 may regulate cell growth via epigenetic regulation of HOXB13 gene expression in DU145 prostate cancer cells.

  9. Incineration of oxygenated volatile organic compounds. Experimental study and kinetic modeling of the oxidation of methyl ethyl ketone, ethyl acetate and butan-2-ol in methane flames; Incineration de composes organiques volatils oxygenes. Etude experimentale et modelisation cinetique de l'oxydation de la methyl ethyl cetone, de l'acetate d'ethyle et du butan-2-ol dans des flammes de methane

    Energy Technology Data Exchange (ETDEWEB)

    Decottignies, V.

    2000-12-01

    This work deals with the low pressure (0.05 atm) degradation of three volatile organic compounds (VOCs): methyl-ethyl-ketone, ethyl acetate and butan-2-ol, in premixed stoichiometric laminar methane flames seeded with 1 to 3% of each VOC. Molar fraction profiles of species have been obtained using microprobe sampling coupled with a gas chromatography and a mass spectroscopy analysis. Temperature profiles have been obtained using the covered thermocouple technique in the presence of the microprobe. The addition of a VOC in the initial reagents mixture leads to an increase of the quantity of intermediate hydrocarbon compounds and in particular of some soot precursor species. The degradation of VOCs leads to the formation of oxygenated intermediates like methanol, dimethyl-ether, acetaldehyde, propanal, acetone and vinyl acetate, the type of VOC having an effect on the quantities produced. The degradation of a VOC can lead to the formation of more toxic or polluting compounds (methyl vinyl ketone, acetic acid and acrolein) than the VOC itself. In the conditions of the study, the intermediate compounds are totally destructed inside the reactional area of the flame front and are no more present in the burnt gases. Sub-mechanisms of VOC oxidation have been developed using experimental observations and the most recent recommendations of the literature. These sub-mechanisms comprise 49 species involved in 241 elementary reactions. Their validation has been performed by comparing the experiment with the kinetic modeling on the molar fraction profiles of the detected species. Experimental data are well reproduced by the model for most species. The addition of a VOC inside the initial reagents mixture creates an important reactivity increase, in particular in the case of butan-2-ol seeded flames. The analysis of reactional ways has permitted to draw out the main reactions responsible for the degradation of the 3 VOCs and the ways of formation and consumption of the

  10. Métastases gastro-intestinales du cancer du sein: à propos de 2 cas

    Science.gov (United States)

    Loubna, Mezouar; Mohamed, El Hfid; Tijani, El Harroudi; Fouzia, Ghadouani; Hanane, Haj Kacem; Zouhour, Bourhaleb; Asmae, Ouabdelmoumen

    2013-01-01

    Le cancer du sein est le cancer le plus fréquent chez la femme, notamment au Maroc, avec un taux de mortalité élevé. Les métastases gastro-intestinales d'un carcinome canalaire du sein sont rares. Leur diagnostic est difficile du fait de la nature non spécifique des symptômes. Nous rapportons deux observations originales de métastases gastroduodénales d'un cancer canalaire infiltrant du sein. Les métastases gastro-intestinales du cancer du sein sont très rares; la présence de symptômes gastro-intestinaux chez une malade ayant un antécédent de cancer du sein doit faire suspecter une atteinte métastatique gastro-intestinale. PMID:24198876

  11. Session du Conseil du CERN : le ministre britannique, Robert Jackson, souligne l'intérêt de on pays pour l'avenir du CERN : décisions du Conseil pour la mise en oeuvre des recommandations du Comité d'évaluation du CERN: départ anticipé pour 200 membres au moins du personnel - mise à jour de la méthode de calcule pour les contributions des Etats Membres au budget

    CERN Multimedia

    CERN Press Office. Geneva

    1988-01-01

    Session du Conseil du CERN : le ministre britannique, Robert Jackson, souligne l'intérêt de on pays pour l'avenir du CERN : décisions du Conseil pour la mise en oeuvre des recommandations du Comité d'évaluation du CERN: départ anticipé pour 200 membres au moins du personnel - mise à jour de la méthode de calcule pour les contributions des Etats Membres au budget

  12. [DNA methylation and epigenetics].

    Science.gov (United States)

    Vaniushin, B F

    2006-09-01

    In eukaryotic cells, nuclear DNA is subject to enzymatic methylation with the formation of 5-methylcytosine residues, mostly within the CG and CNG sequences. In plants and animals this DNA methylation is species-, tissue-, and organelle-specific. It changes (decreases) with age and is regulated by hormones. On the other hand, genome methylation can control hormonal signal. Replicative and post-replicative DNA methylation types are distinguished. They are mediated by multiple DNA methyltransferases with different site-specificity. Replication is accompanied by the appearance of hemimethylated DNA sites. Pronounced asymmetry of the DNA strand methylation disappears to the end of the cell cycle. A model of methylation-regulated DNA replication is proposed. DNA methylation controls all genetic processes in the cell (replication, transcription, DNA repair, recombination, and gene transposition). It is the mechanism of cell differentiation, gene discrimination and silencing. In animals, suppression of DNA methylation stops development (embryogenesis), switches on apoptosis, and is usually lethal. Disruption of DNA methylation pattern results in the malignant cell transformation and serves as one of the early diagnostic features of carcinogenesis. In malignant cell the pattern of DNA methylation, as well as the set of DNA methyltransferase activities, differs from that in normal cell. In plants inhibition of DNA methylation is accompanied by the induction of seed storage and florescence genes. In eukaryotes one and the same gene can be simultaneously methylated both at cytosine and adenine residues. It can be thus suggested, that the plant cell contains at least two different, and probably, interdependent systems of DNA methylation. The first eukaryotic adenine DNA methyltransferase was isolated from plants. This enzyme methylates DNA with the formation of N6-methyladenine residues in the sequence TGATCA (TGATCA-->TGm6ATCA). Plants possess AdoMet-dependent endonucleases

  13. Des Taiwanais dans Ie sud du Fujian

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Se trouvant dans le sud-est de la Chine au bord dela mer, la province du Fujian s’appelle aussi toutsimplement "Min". Les anc(?)tres d’une grande partie de lapopulation de Taiwan sont venus du Fujian (Min). Les deux

  14. Le vide univers du tout et du rien

    CERN Document Server

    Diner, Simon

    1997-01-01

    Pourquoi l'Univers plutôt que le vide ? Le temps et l'espace existent-ils en l'absence de l'Univers ? Que reste-t-il quand tout est enlevé ? Pourquoi quelque chose plutôt que rien ? Depuis des siècles, ces interrogations mobilisent philosophes et physiciens. Mais aujourd'hui, le vide n'est pas le rien. Il serait même l'acteur central de l'histoire de la matière et de l'Univers, le partenaire privilégié de la physique. Vide et matière ne sont plus deux manifestations séparées de la nature, mais deux aspects d'une même réalité. Le vide est l'état de base dont la matière émerge, sans couper son cordon ombilical Le vide comme Univers du rien cède la place au vide comme Univers du tout. Que le vide puisse être conçu par les physiciens comme réservoir potentiel d'univers, voici qui ne devrait laisser personne indifférent. Ce livre ouvre un débat et nous convie à une réflexion surprenante.

  15. Image du savoir, image du pouvoir dans le Lapidaire

    Directory of Open Access Journals (Sweden)

    Marta LACOMBA

    2007-01-01

    Full Text Available À travers le prologue et les enluminures de présentation, le Lapidaire d’Alphonse X oriente l’interprétation de l’œuvre. Ces paratextes mettent en avant le rôle capital du savoir, représenté par la métaphore du trésor caché, qui a ici une valeur topique. Ils mettent également en exergue le rôle que s’attribue le roi dans la transmission de ce savoir, et placent cette nouvelle attribution royale au cœur de son projet politique.A través del prólogo y las miniaturas de presentación, el Lapidario de Alfonso X orienta la interpretación de la obra. Estos paratextos subrayan el papel capital del saber, representado por la metáfora del tesoro escondido, que tiene aquí un valor tópico. Ponen asimismo de manifiesto el papel que se atribuye el monarca en la transmisión de ese saber y colocan esta nueva atribución real en el centro de su proyecto político.

  16. Les esclaves du commandant Quiquandon

    OpenAIRE

    Tymowski, Michal

    2003-01-01

    Le 10 janvier 1895, Albert Grodet, gouverneur général du Soudan français, adressa au ministère des Colonies une dépêche accusant le commandant Quiquandon, dirigeant de la région Nord-Est (Ségou), d'exploiter illégalement un domaine sur lequel travaillent 140 esclaves. À partir de ce cas particulier, l'auteur analyse les conflits qui existaient à l'époque entre l'administration civile et un groupe d'officiers soudanais. Il se demande si la possession d'esclaves par des officiers, prenant...

  17. Du comptoir à la toge

    OpenAIRE

    Buti, Gilbert

    2007-01-01

    Descendant d’une famille de petits notables du Dauphiné, Antoine Anthoine (1749-1826) qui n’a pas pu accéder à la magistrature se destine à la marchandise. Après un apprentissage à Marseille au comptoir des Seimandy, il est nommé, par ces négociants, régisseur pour leur commandite de Constantinople. La mobilisation de sa proche parenté et les soutiens des pouvoirs politiques locaux, nationaux et internationaux lui permettent d’obtenir une mission destinée à ouvrir le commerce de la Russie mér...

  18. Aventures radiophoniques du Nouveau Roman

    Directory of Open Access Journals (Sweden)

    Beatrice Nickel

    2015-12-01

    Full Text Available  Aventures radiophoniques du Nouveau Roman Colloque international organisé par l’Université Paul-Valéry Montpellier, en partenariat avec l’Université de Stuttgart 19-20 novembre 2015   Organisateurs :  Pierre-Marie Héron, Annie Pibarot, Université Paul-Valéry Montpellier, centre de recherche Rirra21. Françoise Joly, Beatrice Nickel, Universität Stuttgart 

  19. Kristallstrukturen und spektroskopische Eigenschaften von 23-Phospha-1, 3-dionaten und 1, 3-Dionaten des Calciums - ein Vergleich am Beispiel der 1, 3-Diphenyl- und 1, 3-Di(tert-butyl)-Derivate = Crystal Structures and Spectroscopic Properties of 23-Phospha-1, 3-dionates and 1, 3-Dionates of Calcium - Comparative Studies on the 1, 3-Diphenyl and 1, 3-Di(tert-butyl) Derivatives

    NARCIS (Netherlands)

    Becker, Gerd; Niemeyer, Mark; Mundt, Otto; Schwarz, Wolfgang; Westerhausen, Matthias; Ossberger, Manfred W.; Mayer, Peter; Nöth, Heinrich; Zhong, Zhiyuan; Dijkstra, Pieter J.; Feijen, Jan

    2004-01-01

    Der Wasserstoff-Metall-Austausch zwischen Dibenzoylphosphan und Calciumcarbid in Tetrahydrofuran (THF) ergibt nach Zusatz des Liganden 1, 3, 5-Trimethyl-1, 3, 5-triazinan (TMTA) den als Kokristallisat mit Benzol isolierten zweikernigen Komplex Bis[(tmta-N, N, N)calcium-bis(dibenzoylphosphanid)] (1a)

  20. Comparative analysis of rubber seed methyl ester with other methyl ...

    African Journals Online (AJOL)

    Comparative analysis of rubber seed methyl ester with other methyl esters. ... In order to achieve a two-step transesterification process was developed to convert rubber seed oil to its methyl esters. The first step, acid catalyzed ... Article Metrics.

  1. Sociologie et sociolinguistique du franbreu

    Directory of Open Access Journals (Sweden)

    Ben-Rafael Eliezer

    2014-07-01

    Full Text Available Des enquêtes ont montré que plus de 20 % des adultes israéliens ont quelque connaissance du français. Parmi cette population, 250 000 à 300 000 personnes pouvaient être considérées comme francophones. Le français a affirmé une présence importante – pas toujours reconnue – dès la phase cruciale du développement de cette société. Une immigration de masse suivit la création de l’État (1948 dont la population a quasiment triplé en moins de deux décennies, avec l’arrivée de plus de 200 000 immigrants d’Afrique du Nord et des dizaines de milliers des Balkans et du Moyen-Orient. Beaucoup parmi ces immigrants étaient francophones – le français étant pour eux soit la première langue soit une deuxième qu’ils contrôlaient. C’est depuis lors que la présence du français est devenue démographiquement significative dans la société israélienne, se prolongeant de nos jours dans l’immigration en provenance de France qui se poursuit jusqu’à aujourd’hui. Comme nous l’avons montré ailleurs (Ben-Rafael et Ben-Rafael 2013, Israël fait l’expérience simultanée de plusieurs francophonies originales qui diffèrent par leurs sources aussi bien que leurs expressions (Ben-Rafael et Ben-Rafael 2013. Un premier modèle est le « français vernaculaire » (voir Boudras-Chapon 2008 amené par les immigrants de classes défavorisées arrivant d’Afrique du nord qui se sont regroupés en Israël. Leur français n’a offert qu’une faible résistance à l’hébreu qui s’est imposée dans le processus d’intégration. Un bilinguisme fonctionnant sur un mode additif au début qui s’est mué progressivement en modèle soustractif. Un second modèle concerne les immigrants de même origine ainsi que des immigrants francophones d’autres pays (pays balkaniques, Turquie ou Egypte formant une strate instruite de classe moyenne, pour qui le français était d’utilisation quotidienne aussi bien que de langue de

  2. Rejets et environnement du CERN

    CERN Document Server

    Vojtyla, P

    2007-01-01

    La radioactivité de l’environnement autour de l’Organisation Européenne pour la Recherche Nucléaire (CERN) et les doses de rayonnements qui en résultent pour la population avoisinante sont contrôlées par la Commission de Sécurité du CERN et de manière indépendante par les autorités compétentes des deux États Hôtes, l’Institut de Radioprotection et de Sûreté Nucléaire (IRSN) côté France et l’Office Fédéral de la Santé Publique (OFSP) côté Suisse (voire Chapitre 8.6). Dans ce rapport, les résultats de mesures concernent en particulier le territoire suisse. L’ensemble des mesures effectuées en 2006 prouve que le fonctionnement des installations du CERN était sans conséquence radiologique sur l’environnement et la population. Le contrôle des émissions montre que les rejets effectifs se situent, également en 2006, nettement en dessous des limites réglementaires. Ce constat est confirmé par le contrôle des immissions dans l’environnement. Le CERN a bien respecté en 2...

  3. Bases en technique du vide

    CERN Document Server

    Rouviere, Nelly

    2017-01-01

    Cette seconde édition, 20 ans après la première, devrait continuer à aider les techniciens pour la réalisation de leur système de vide. La technologie du vide est utilisée, à présent, dans de nombreux domaines très différents les uns des autres et avec des matériels très fiables. Or, elle est souvent bien peu étudiée, de plus, c'est une discipline où le savoir-faire prend tout son sens. Malheureusement la transmission par des ingénieurs et techniciens expérimentés ne se fait plus ou trop rapidement. La technologie du vide fait appel à la physique, à la chimie, à la mécanique, à la métallurgie, au dessin industriel, à l'électronique, à la thermique, etc. Cette discipline demande donc de maîtriser des techniques de domaines très divers, et ce n'est pas chose facile. Chaque installation est en soi un cas particulier avec ses besoins, sa façon de traiter les matériaux et celle d'utiliser les matériels. Les systèmes de vide sont parfois copiés d'un laboratoire à un autre et le...

  4. RADICAL GRAFTING OF POLY(METHYL METHACRYLATE) ONTO SILICON-WAFERS, GLASS SLIDES AND GLASS-BEADS

    NARCIS (Netherlands)

    FOLKERSMA, R; CHALLA, G; SCHOUTEN, AJ

    1991-01-01

    Poly(methyl methacrylate) was grafted onto glass beads, glass slides and silicon wafers using an immobilized radical initiator. The polymeric monolayers had thicknesses varying from a few hundred to 4000 angstrom, being up to 10 times larger than the radii of gyration of comparable free polymers. Du

  5. Different hydrogen-bonded chains in the crystal structures of three alkyl N-[(E-1-(2-benzylidene-1-methylhydrazinyl-3-hydroxy-1-oxopropan-2-yl]carbamates

    Directory of Open Access Journals (Sweden)

    Thais C. M. Noguiera

    2015-07-01

    Full Text Available The crystal structures of three methylated hydrazine carbamate derivatives prepared by multi-step syntheses from l-serine are presented, namely benzyl N-{(E-1-[2-(4-cyanobenzylidene-1-methylhydrazinyl]-3-hydroxy-1-oxopropan-2-yl}carbamate, C20H20N4O4, tert-butyl N-{(E-1-[2-(4-cyanobenzylidene-1-methylhydrazinyl]-3-hydroxy-1-oxopropan-2-yl}carbamate, C17H22N4O4, and tert-butyl N-[(E-1-(2-benzylidene-1-methylhydrazinyl-3-hydroxy-1-oxopropan-2-yl]carbamate, C16H23N3O4. One of them shows that an unexpected racemization has occurred during the mild-condition methylation reaction. In each crystal structure, the molecules are linked into chains by O—H...O hydrogen bonds, but with significant differences between them.

  6. Rotational Investigation of the Adducts of Formic Acid with Alcohols, Ethers and Esters

    Science.gov (United States)

    Evangelisti, Luca; Spada, Lorenzo; Li, Weixing; Caminati, Walther

    2016-06-01

    Mixtures of formic acid with methyl alcohol, with isopropyl alcohol, with tert-butyl alcohol, with dimethylether and with isopropylformiate have been supersonically expanded as pulsed jets. The obtained cool plumes have been analyzed by Fourier transform microwave spectroscopy. It has been possible to assign the rotational spectra of the 1:1 adducts of formic acid with tert-butyl alcohol, with dimethyl ether and with isopropylformiate. The conformational shapes and geometries of these adducts, as well as the topologies of their itermolecular hydrogen bonds will be presented. An explanation is given of the failure of the assignments of the rotational spectra of the adducts of formic acid with methyl alcohol and isopropyl alcohol.

  7. De Sumer à Seattle, le voyage du bout du monde

    Directory of Open Access Journals (Sweden)

    Olivier Walther

    2008-12-01

    Full Text Available « Les affaires qui se nouent par-dessus les frontières qui séparent les peuples ne font pas que ces frontières n'existent pas » notait Émile Durkheim en 1895 (1895 : 113. Un peu plus d’un siècle plus tard, l’ouvrage de William J. Bernstein intitulé A Splendid Exchange et sous-titré de manière inspirée How Trade Shaped the World vient apporter une confirmation étayée au sociologue français. De Sumer où fut introduit le commerce du cuivre 3000 ans avant Jésus-Christ, à Seattle où se tint la tr...

  8. Le cas du Haut-Adige ou Tyrol du Sud

    Directory of Open Access Journals (Sweden)

    Licia Bagini Scantamburlo

    2007-06-01

    Full Text Available La situation de cette région italienne est vraiment emblématique des rapports entre « les territoires et l’identité » à cause de la présence de différentes communautés linguistiques autochtones, dont les plus importantes sont les minorités germanophone et latine. S’il est vrai que cette situation existe également dans d’autres régions italiennes, il est incontestable que dans le Haut-Adige/Tyrol du Sud elle présente des caractéristiques très spécifiques et uniques pour l’Italie, car les italo...

  9. COMMUNICATION DU CREDIT AGRICOLE - French version only

    CERN Multimedia

    2003-01-01

    La Direction du Crédit Agricole informe son aimable clientèle du CERN des jours et heures d'ouverture de l'agence du site de Prévessin à compter du mardi 14 janvier 2003 : 1. Horaires pour les opérations bancaires courantes 7 jours sur 7 et 24h/24 avec l'espace libre service bancaire. 2. Horaires conseil du mardi au vendredi - Mardi, de 9h. à 12h. et de 14h.15 à 16h.30. - Mercredi, jeudi et vendredi, de 9h. à 12h. et de 13h.30 à 16h.30. Deux collaboratrices au lieu d'une seront désormais présentes toute la journée du mardi au vendredi pour vous accueillir, vous informer et vous conseiller en crédits et placements (réception conseil sur rendez-vous). Autre nouveauté : les mêmes conseillers seront aussi à votre disposition le samedi, sur notre agence de Gex, de 8h.15 à 13h.05, notamment pour les études de financements habitat. La Direction et toute l'équipe de l'agence du Crédit Agricole vous souhaitent une excellent année 2003.

  10. Approche de prise en charge du trouble du spectre de l’autisme

    Science.gov (United States)

    Lee, Patrick F.; Thomas, Roger E.; Lee, Patricia A.

    2015-01-01

    Résumé Objectif Se pencher sur les critères diagnostiques du trouble du spectre de l’autisme (TSA) comme les définit le Manuel diagnostique et statistique des troubles mentaux, cinquième édition (DSM-V), et concevoir une approche de prise en charge du TSA à l’aide du cadre CanMEDS–Médecine familiale (CanMEDS-MF). Sources d’information Le DSM-V, publié par l’American Psychiatric Association en mai 2013, énonce de nouveaux critères diagnostiques du TSA. Le cadre CanMEDS-MF du Collège des médecins de famille du Canada fournit un plan d’orientation pour la prise en charge complexe du TSA. Nous avons utilisé des données recueillies par le Centers for Disease Control and Prevention afin de déterminer la prévalence du TSA, ainsi que la revue systématique et méta-analyse détaillée effectuée par le National Institute for Health and Care Excellence du R.-U. pour ses lignes directrices sur le TSA dans le but d’évaluer les données probantes issues de plus de 100 interventions. Message principal Selon les données du Centers for Disease Control and Prevention, la prévalence du TSA se chiffrait à 1 sur 88 en 2008 aux États-Unis. La classification du TSA dans la quatrième édition du DSM incluait l’autisme, le syndrome d’Asperger, le trouble envahissant du développement et le trouble désintégratif de l’enfance. La dernière révision du DSM-V réunit tous ces troubles sous la mention TSA, avec différents niveaux de sévérité. La prise en charge du TSA est complexe; elle exige les efforts d’une équipe multidisciplinaire ainsi que des soins continus. Les rôles CanMEDS-MF fournissent un cadre de prise en charge. Conclusion Les médecins de famille sont au cœur de l’équipe de soins multidisciplinaire pour le TSA, et le cadre CanMEDS-MF tient lieu de plan détaillé pour guider la prise en charge d’un enfant atteint de TSA et aider la famille de cet enfant.

  11. Synthesis of DL-adrenaline (methyl C{sup 14}) (1961); Synthese de la DL-adrenaline (methyle {sup 14}C) (1961)

    Energy Technology Data Exchange (ETDEWEB)

    Pichat, L.; Audinot, M. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1961-07-01

    The sodium derivative of 5-3-4 dibenzyl oxyphenyl 2-oxazolidinone reacted with methyl iodide {sup 14}C, in stoichiometric quantity, gives rise to the corresponding N-methyl {sup 14}C derivative. The oxazolidinone ring is opened by concentrated hydrochloric acid and the benzyl groups removed by catalytic hydrogenolysis. Adrenaline methyl {sup 14}C is then purified on Dowex 50 X-12 exchange resin. Overall-yield is 45 per cent based upon methyl iodide {sup 14}C. (author) [French] Le derive sode de la (dibenzyloxy-3-4-phenyl)-5 oxazolidinone-2 traite par l'iodure de methyle {sup 14}C, en proportion stoechiometrique, fournit le derive N-methyle {sup 14}C correspondant. Apres ouverture du cycle oxazolidinone par HCL concentre et debenzylation par hydrogenation catalytique, on purifie l'adrenaline (methyle {sup 14}C) par chromatographie sur resine echangeuse Dowex 50 X-12. Le rendement est de 45 pour cent par rapport a l'iodure de methyle {sup 14}C. (auteurs)

  12. Nouvelles du Centre Aéré de l’Association du Personnel du CERN

    CERN Multimedia

    Jardin d'enfants

    2015-01-01

    Cet été 2015, durant quatre semaines d’été, le Centre Aéré a accueilli plus de 40 enfants âgés de 4 à 6 ans. Devant le succès rencontré, et à la demande des parents, il a été décidé d’en doubler la capacité maximale. A l'été 2016, du 4 au 29 juillet, la structure pourra accueillir les enfants de 4 ans révolus et de moins de 7 ans (nés après le 31/07/2009 mais avant  01/07/2012). Les inscriptions se feront à la semaine durant le mois d'Avril 2016. Les programmes sont en cours d'élaboration cependant nous pouvons déjà vous communiquer le thème conducteur du centre qui sera : à la découverte d'un continent différent chaque ...

  13. Sylvain Fagot, Le cirque. Entre culture du corps et culture du risque

    OpenAIRE

    Crochet-Giacometti, Nicolas

    2011-01-01

    Cet ouvrage écrit par Sylvain Fagot, chercheur en sociologie associé à l'université du Québec, et auteur d'une thèse soutenue en 2003 intitulée « Ethno-sociologie du cirque. Arts de la piste / Arts du corps / Arts du risque », s'intéresse à un monde peu connu : celui du cirque. L'objectif y est de montrer comment chaque forme du cirque, le cirque dit « classique » et le cirque dit « nouveau », ont des stratégies sociales et économiques différentes mais surtout un rapport au corps et au risque...

  14. Chapitre VI. Prudence du financement

    OpenAIRE

    Jambard, Pierre

    2015-01-01

    L’histoire financière de la société permet de comprendre bien des traits de son histoire. Comme toutes les entreprises du bâtiment et des travaux publics, la Société Auxiliaire s’est trouvée devant la nécessité de disposer d’importants capitaux circulants. Grâce à une gestion financière efficace, elle est, en général, parvenue à dégager de son activité les fonds nécessaires, bien que l’aisance de la trésorerie quotidienne n’ait été acquise qu’avec la reconversion. Les années 1927-1946 sont ce...

  15. DU COTÉ DE CHEZ SOI

    OpenAIRE

    Marc Smeets

    2013-01-01

    Le voyage en Hollande, au XIXe siècle, s'inscrit dans une longue tradition où résonnent les notions de liberté, tolérance et commerce, mais il acquiert aussi une spécificité étant donné l’importance que prend la figure du « chez soi » : les Pays-Bas, terre d'agrément où le voyageur français se sent à l'aise et où il aimerait, si possible, vivre. Proust, de ce point de vue-là, ne fait rien de neuf quand il rêve dans la Recherche d'une « vie domestique » en terre batave. Les Pays-Bas, pour le v...

  16. L’abolition du vieillissement

    Directory of Open Access Journals (Sweden)

    Josef Reindl

    2012-02-01

    Full Text Available I « L’humanité vieillit à un rythme inimaginable. (... »« L’humanité vieillit à un rythme inimaginable. Nous devons résoudre le problème de notre propre vieillissement pour résoudre celui du monde entier. » M. Schirrmacher, l’un des intellectuels médiatiques les plus connus de l’Allemagne, joue comme toujours de façon magistrale la partition de l’effroi. Il ne se contente nullement de s’arranger avec son propre vieillissement, mais il veut sauver le monde à travers « une révolution militante...

  17. Scientific opinion on the evaluation of substances as acceptable previous cargoes for edible fats and oils

    OpenAIRE

    Petersen, Annette

    2017-01-01

    Shipping of edible fats and oils into Europe is permitted in bulk tanks, provided that the previous cargo is included in a positive list. The European Commission requested EFSA to evaluate the acceptability as previous cargoes for fats and oils the substances calcium lignosulphonate, methyl acetate, ethyl tert-butyl ether (ETBE) and ammonium sulphate. The evaluation was based on the same criteria as those used for the evaluation of the substances currently on the list in the Annex to Commissi...

  18. Modeling the Fate of Groundwater Contaminants Resulting from Leakage of Butanol-blended Fuel

    Science.gov (United States)

    2010-03-01

    can lead to significant consequences. As an example, consider methyl tert-butyl ether (MTBE). MTBE was added to gasoline as a replacement for...formulations of gasoline and alcohol products available in the market, most commonly, gasoline and ethyl alcohol (also known as ethanol) mixture. However...engines ( kerosene /jet fuel). Table 2-1 presents the difference in properties between distillates for gasoline and jet fuel (Bartis et al., 2008

  19. 液相氧化羰基化合成碳酸二乙酯的新型催化体系CuCl/1,10-菲罗啉/N-甲基咪唑%A Novel Catalyst CuCl/1,10-Phenanthroline/N-Methylimidazole for the Oxidative Carbonylation of Ethanol to Diethyl Carbonate

    Institute of Scientific and Technical Information of China (English)

    莫婉玲; 李光兴; 朱永强; 熊辉; 梅付名

    2003-01-01

    @@ Diethyl carbonate (DEC) is one of the important green chemicals widely used for organic synthesis because of its various functional groups. DEC is a better octane blending fuel, and has more oxygen in the molecule than methyl tert-butyl ether (MTBE), 40.6% versus 18.2%, which reduces emissions from gasoline and diesel engine. For these reasons many studies on the production of DEC have been extensively carried out.

  20. 46 CFR Table 1 to Part 153 - Summary of Minimum Requirements

    Science.gov (United States)

    2010-10-01

    ...), (c), (g), .409, .526 I-C Diethyl ether, see Ethyl ether Di-(2-ethylhexyl) phosphoric acid C S/P III... Ethyl tert-butyl ether C P III 4m PV Restr A .409 I-C Ethyl butyrate C P III 4m PV Restr A .409 I-D... glycol ethyl ether acetate, see 2-Ethoxyethyl acetate Ethylene glycol methyl ether acetate C P III...

  1. 46 CFR Table 151.05 to Subpart 151... - Summary of Minimum Requirements

    Science.gov (United States)

    2010-10-01

    ... ether, see Ethyl ether Diisobutylamine Atmos. Amb. III 1 i i 2 i i Integral Gravity PV Restr. II G-1 NR... butyl ether Ethylene glycol tert-butyl ether Ethylene glycol ethyl ether Ethylene glycol methyl ether.... Pressure SR Restr. II P-2 Inert Vent F Yes .50-10.50-12 I-B .40-1(c) 4 Ethyl ether Atmos. Amb. II 1NA 2 i...

  2. Sulphite metabolism; Metabolisme du sulfite

    Energy Technology Data Exchange (ETDEWEB)

    Fromageot, P.; Chapeville, F. [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

    1960-07-01

    Although the formation of sulphite by micro-organisms was observed as early as 1914 by Neuberg, it was only in 1932 that Nightingale showed it to be present inside cells, in the case of tomato leaf stalks, its formation being due to the reaction: SO{sub 3}H{sup -} + (S{sub 2}O{sub 3}){sub 2}{sup --} {yields} S{sub 2}O{sub 3}{sup --} + O{sub 3}S{sub 2}O{sub 3}{sup --}. The presence of the thiosulphate formed was shown by the high refractive index of its barium salt. Today we have a certain amount of data concerning the formation and use of sulphite in the living cell, even through the knowledge is still incomplete. In this article we will describe and discuss the facts which are known, with particular reference to the oxidation of sulphite. (author) [French] Si la formation de sulfite par des micro-organismes a ete observee des 1914 par Neuberg, sa presence a l'interieur des cellules a ete demontree pour la premiere fois par Nightingale en 1932, dans des tiges et des feuilles de tomates, par la reaction: SO{sub 3}H{sup -} + (S{sub 2}O{sub 3}){sub 2}{sup --} {yields} S{sub 2}O{sub 3}{sup --} + O{sub 3}S{sub 2}O{sub 3}{sup --}. Le thiosulfate forme etait mis en evidence par l'indice de refraction eleve de son sel de baryum. Aujourd'hui on possede un certain nombre de donnees, cependant encore tres incompletes, sur la formation du sulfite et son utilisation par la cellule vivante. Dans cet expose nous decrirons et discuterons quelques-unes de ces acquisitions, tout particulierement celles relatives a l'oxydation du sulfite. (auteur)

  3. Sulphite metabolism; Metabolisme du sulfite

    Energy Technology Data Exchange (ETDEWEB)

    Fromageot, P.; Chapeville, F. [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

    1960-07-01

    Although the formation of sulphite by micro-organisms was observed as early as 1914 by Neuberg, it was only in 1932 that Nightingale showed it to be present inside cells, in the case of tomato leaf stalks, its formation being due to the reaction: SO{sub 3}H{sup -} + (S{sub 2}O{sub 3}){sub 2}{sup --} {yields} S{sub 2}O{sub 3}{sup --} + O{sub 3}S{sub 2}O{sub 3}{sup --}. The presence of the thiosulphate formed was shown by the high refractive index of its barium salt. Today we have a certain amount of data concerning the formation and use of sulphite in the living cell, even through the knowledge is still incomplete. In this article we will describe and discuss the facts which are known, with particular reference to the oxidation of sulphite. (author) [French] Si la formation de sulfite par des micro-organismes a ete observee des 1914 par Neuberg, sa presence a l'interieur des cellules a ete demontree pour la premiere fois par Nightingale en 1932, dans des tiges et des feuilles de tomates, par la reaction: SO{sub 3}H{sup -} + (S{sub 2}O{sub 3}){sub 2}{sup --} {yields} S{sub 2}O{sub 3}{sup --} + O{sub 3}S{sub 2}O{sub 3}{sup --}. Le thiosulfate forme etait mis en evidence par l'indice de refraction eleve de son sel de baryum. Aujourd'hui on possede un certain nombre de donnees, cependant encore tres incompletes, sur la formation du sulfite et son utilisation par la cellule vivante. Dans cet expose nous decrirons et discuterons quelques-unes de ces acquisitions, tout particulierement celles relatives a l'oxydation du sulfite. (auteur)

  4. Crystal structure of (2-{[3,5-bis(1,1-dimethylethyl-4-hydroxyphenyl](5-methyl-2H-pyrrol-2-ylidenemethyl}-5-methyl-1H-pyrrolido-κ2N,N′difluoridoboron

    Directory of Open Access Journals (Sweden)

    Yukio Morimoto

    2015-09-01

    Full Text Available The title compound, C25H31BF2N2O, is a potential boron tracedrug in boron neutron capture therapy (BNCT, in which the B atom adopts a distorted BN2F2 tetrahedral geometry: it is soluble in dimethyl sulfoxide, dimethylformamide and methanol. The pyrrolylidenemethylpyrrole triple fused ring system is almost planar (r.m.s. deviation = 0.031 Å and subtends a dihedral angle of 47.09 (5° with the plane of the pendant phenol ring. The phenol –OH group is blocked from forming hydrogen bonds by the adjacent bulky tert-butyl groups. In the crystal, inversion dimers linked by pairs of very weak C—H...F interactions generate R22(22 loops.

  5. Daphne du Maurier' unustatud jutud / Udo Uibo

    Index Scriptorium Estoniae

    Uibo, Udo, 1956-

    2011-01-01

    Ajalehe "The Independent" teatel kavatseb kirjastus "Virago" maikuus avaldada Daphne Du Maurier lühiproosa kogumiku "Nukk" (The Doll), mille on koostanud tema loomingu suur austaja Ann Willmore ja mis sisaldab 13 unustatud ja seni avaldamata novelli

  6. Flaubert et Du Camp : quelques remarques

    Directory of Open Access Journals (Sweden)

    Michel Brix

    2016-12-01

    Full Text Available Les spécialistes de Flaubert ont fait de nombreux reproches à Maxime Du Camp et ne prêtent plus guère d’attention à ce qu’il a écrit. C’est une situation très regrettable, qui prive les lecteurs d’informations nombreuses, susceptibles d’éclairer les enjeux mais aussi les impasses et les contradictions du projet esthétique de Flaubert. Quelques cas significatifs sont évoqués dans le présent article, qui se penche plus particulièrement sur la ressemblance entre un passage du livre de Du Camp Le Nil (1854 et les lignes de L’Éducation sentimentale (1869 qui rapportent l’“apparition” de Mme Arnoux.

  7. Inauguration du C/R Forum (Belgique

    Directory of Open Access Journals (Sweden)

    2009-04-01

    Full Text Available Le 16 février dernier, la Vlaamse beroepsvereniging Conservatie en Restauratie Forum (C/R Forum a été constituée à l'initiative de 18 personnes du milieu de la conservation/restauration et du secteur de la protection du patrimoine. Etant donné que la conservation et la gestion du patrimoine culturel mobilier et immobilier de même que la formation et la recherche relèvent des communautés et des régions, la nécessité est apparue depuis un certain temps de créer une organisation Flamande au sei...

  8. Daphne du Maurier' unustatud jutud / Udo Uibo

    Index Scriptorium Estoniae

    Uibo, Udo, 1956-

    2011-01-01

    Ajalehe "The Independent" teatel kavatseb kirjastus "Virago" maikuus avaldada Daphne Du Maurier lühiproosa kogumiku "Nukk" (The Doll), mille on koostanud tema loomingu suur austaja Ann Willmore ja mis sisaldab 13 unustatud ja seni avaldamata novelli

  9. ENZYMOLOGY OF ARSENIC METHYLATION

    Science.gov (United States)

    Enzymology of Arsenic MethylationDavid J. Thomas, Pharmacokinetics Branch, Experimental Toxicology Division, National Health and Environmental Effects Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park...

  10. Lysine methylation: beyond histones

    Institute of Scientific and Technical Information of China (English)

    Xi Zhang; Hong Wen; Xiaobing Shi

    2012-01-01

    Posttranslational modifications (PTMs) of histone proteins,such as acetylation,methylation,phosphorylation,and ubiquitylation,play essential roles in regulating chromatin dynamics.Combinations of different modifications on the histone proteins,termed 'histone code' in many cases,extend the information potential of the genetic code by regulating DNA at the epigenetic level.Many PTMs occur on non-histone proteins as well as histones,regulating protein-protein interactions,stability,localization,and/or enzymatic activities of proteins involved in diverse cellular processes.Although protein phosphorylation,ubiquitylation,and acetylation have been extensively studied,only a few proteins other than histones have been reported that can be modified by lysine methylation.This review summarizes the current progress on lysine methylation of nonhistone proteins,and we propose that lysine methylation,like phosphorylation and acetylation,is a common PTM that regulates proteins in diverse cellular processes.

  11. DU-127090 Solvay/H Lundbeck.

    Science.gov (United States)

    Wolf, William

    2003-01-01

    DU-127090 is a mixed dopamine antagonist/serotonin agonist in development by Solvay and H Lundbeck as a potential treatment for psychosis and schizophrenia, for which it is in phase II clinical trials. In August 2002, phase II trials were ongoing and Lundbeck expected to commence phase III trials in 2003 and file an NDA after 2004. DU-127090 is also under development for Parkinson's disease, for which it is in phase I clinical trials.

  12. La fin du risque zéro : du homegrown jihadism au terrorisme du loup solitaire

    Directory of Open Access Journals (Sweden)

    Rémi Baudouï

    2015-09-01

    Full Text Available Le risque zéro représente un moment historique particulier dans la conceptualisation de la socio-politique du risque. Son application repose au début des années 1980 sur l’hypothèse de la possibilité de progresser dans le domaine de l’anticipation et de la gestion sécuritaire des crises potentielles au point de pouvoir prémunir les populations contre toute forme de menace. Il fut employé dans les domaines de la protection civile et de la sécurité militaire. Comme élément de gouvernance politique, il réfutait l’idée selon laquelle le risque existe en préalable comme catégorie d’acceptabilité collective de la menace.

  13. Aux frontières du politique et du religieux

    Directory of Open Access Journals (Sweden)

    Frédéric Sylvanise

    2006-05-01

    Full Text Available The Autobiography of Miss Jane Pittman met en scène de manière spectaculaire deux figures de leadership noir-américain au XIXe siècle (Ned et au XXe siècle (Jimmy. Ned, fils adoptif de Jane Pittman, se rebaptise Professor Douglass en hommage au leader abolitionniste Frederick Douglass. S’il est fondamentalement laïc (il est instituteur, le texte lui confère néanmoins une dimension religieuse, notamment dans le chapitre intitulé « The Sermon at the River » , qui renvoie à la fois à Moïse (le fleuve et à Jésus (le sermon sur la montagne. Abattu par un tueur à gages, Ned est un martyr dont l’histoire était déjà écrite. Le personnage de Jimmy, attendu par toute une communauté comme le messie (alors que lui aussi est un laïc et un homme qui perd la foi, s’inscrit dans la même histoire. Lettré, éloquent et impliqué dans le mouvement pour les droits civils, il est assassiné comme son prédécesseur. Dans les deux cas, le texte lie donc le politique et le biblique comme s’il ne faisait qu’un : être un leader politique, c’est être un preacher et un messie qui guide le peuple. Il est possible de lire l’évocation de ces deux hommes à la lumière d’une certaine actualité. Ned et Jimmy connaissent en effet un sort proche de celui de Malcolm X et de Martin Luther King, récemment assassinés au moment de l’écriture de The Autobiography of Miss Jane Pittman. C’est l’histoire de la répression du leadership noir, au travers du portrait de deux de ses avatars, qui peut donc se lire en creux ici.

  14. Rapid separation of cyanidin-3-glucoside and cyanidin-3-rutinoside from crude mulberry extract using high-performance countercurrent chromatography and establishment of a volumetric scale-up process.

    Science.gov (United States)

    Choi, Soo-Jung; Choi, Janggyoo; Lee, Chang Uk; Yoon, Shin Hee; Bae, Soo Kyung; Chin, Young-Won; Kim, Jinwoong; Yoon, Kee Dong

    2015-06-01

    This study describes the rapid separation of mulberry anthocyanins; namely, cyanidin-3-glucoside and cyanidin-3-rutinoside, using high-performance countercurrent chromatography, and the establishment of a volumetric scale-up process from semi-preparative to preparative-scale. To optimize the separation parameters, biphasic solvent systems composed of tert-butyl methyl ether/n-butanol/acetonitrile/0.01% trifluoroacetic acid, flow rate, sample amount and rotational speed were evaluated for the semi-preparative-scale high-performance countercurrent chromatography. The optimized semi-preparative-scale high-performance countercurrent chromatography parameters (tert-butyl methyl ether/n-butanol/acetonitrile/0.01% trifluoroacetic acid, 1:3:1:5, v/v; flow rate, 4.0 mL/min; sample amount, 200-1000 mg; rotational speed, 1600 rpm) were transferred directly to a preparative-scale (tert-butyl methyl ether/n-butanol/acetonitrile/0.01% trifluoroacetic acid, 1:3:1:5, v/v; flow rate, 28 mL/min; sample amount, 5.0-10.0 g; rotational speed, 1400 rpm) to achieve separation results identical to cyanidin-3-glucoside and cyanidin-3-rutinoside. The separation of mulberry anthocyanins using semi-preparative high-performance countercurrent chromatography and its volumetric scale-up to preparative-scale was addressed for the first time in this report. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Partial purification and characterization of bacteriocin produced by Enterococcus faecalis DU10 and its probiotic attributes.

    Science.gov (United States)

    Perumal, Venkatesh; Repally, Ayyanna; Dasari, Ankaiah; Venkatesan, Arul

    2016-10-01

    A novel bacteriocin produced by avian duck isolated lactic acid bacterium Enterococcus faecalis DU10 was isolated. This bacteriocin showed a broad spectrum of antibacterial activity against important food-borne pathogens and was purified by size exclusion chromatography followed by reverse-phase high-performance liquid chromatography in a C-18 column. Tricine-SDS PAGE revealed the presence of a band with an estimated molecular mass of 6.3 kDa. The zymogram clearly linked the antimicrobial activity with this band. This result was further confirmed by mass-assisted laser desorption ionization time-of-flight mass spectrometry, since a sharp peak corresponding to 6.313 kDa was detected and the functional groups were revealed by Fourier transform infrared spectroscopy. Bacteriocin DU10 activity was found sensitive to proteinase-K and pepsin and partially affected by trypsin and α-chymotrypsin. The activity of bacteriocin DU10 was partially resistant to heat treatments ranging from 30 to 90°C for 30 min. It also withstood a treatment at 121°C for 10 min. Cytotoxicity of bacteriocin DU10 by methyl-thiazolyl-diphenyl-tetrazolium bromide assay showed that the viability of HT-29 and HeLa cells decreased 60 ± 0.7% and 43 ± 4.8%, respectively, in the presence of 3,200 AU/mL of bacteriocin. The strain withstood 0.3% w/v of bile oxgall and pH 2 affected the bacterial growth between 2 and 4 hr of incubation. Adhesion properties examined with HT-29 cell line showed 69.85% initial population of strain E. faecalis DU10, which was found to be strongly adhered to this cell line. These results conclude bacteriocin DU10 may be used as a potential biopreservative and E. faecalis DU10 may be used as a potential probiont to control Salmonella infections.

  16. Original Paper Performances comparées du HDL-cholestérol et du ...

    African Journals Online (AJOL)

    CT/HDL-C) et du HDL-Cholestérol est le meilleur prédicteur du SMet chez les adultes béninois. L'étude de ..... d'hypertension artérielle avaient observé qu'une ... facteurs tels que l'alimentation et l'activité physique sur les lipides sanguins.

  17. Engagez-vous, devenez délégué(e) du personnel du CERN

    CERN Multimedia

    Staff Association

    2017-01-01

    Dans notre ECHO N° 275, nous avons annoncé les élections à venir au Conseil du personnel du CERN. Dans le présent ECHO, nous vous informons du lancement du processus des élections qui débute par le dépôt des candidatures. Tous les titulaires, boursiers et associés, qui sont aussi membres de l’Association du personnel, peuvent s’engager et déposer leur candidature entre le 11 septembre à 08 h 00 et le 13 octobre 2017 à 17 h 00. N’hésitez plus, remplissez le formulaire de candidature, présentez-vous aux élections au Conseil du personnel afin de pouvoir représenter et défendre vos collègues du personnel du CERN. ÊTRE DÉLÉGUÉ(E), C’EST QUOI ? Poser la question à plusieurs d...

  18. Biokinetics and dosimetry of depleted uranium (DU) in rats implanted with DU fragments.

    Energy Technology Data Exchange (ETDEWEB)

    Guilmette, Ray A.; Hahn, Fletcher F.; Durbin, P. W.

    2004-01-01

    A number of U. S. veterans of the Persian Gulf War were wounded with depleted uranium (DU) metal fragments as a result of 'friendly fire' incidents, in which Abrams tanks and Bradley fighting vehicles were struck by DU anti-armor munitions. Some of the crew members who survived were left with multiple small fragments of DU in their muscles and soft tissues. The number, size and location of the fragments made them inoperable in general, and therefore subject to long-term retention. Because there was inadequate data to predict the potential carcinogenicity of DU fragments in soft tissues, Hahn et al. (2003) conducted a lifespan cancer study in rats. As part of that study, a number of rats were maintained to study the biokinetics and dosimetry of DU implanted intramuscularly in male Wistar rats. Typically, four metal fragments, either as cylindrical pellets or square wafers were implanted into the biceps femoris muscles of the rats. Urine samples were collected periodically during their lifespans, and DU was analyzed in kidneys and eviscerated carcass (minus the implant sites) at death. The daily DU urinary excretion rate increased steeply during the first 30 d after implantation peaking at about 90 d at 3-10 x 10{sup -3}%/d. During the first 150 d, the average excretion rate was 2.4 x 10{sup -3}%/d, decreasing thereafter to about 1 x 10{sup -3}%/d. Serial radiographs were made of the wound sites to monitor gross morphologic changes in the DU implant and the surrounding tissue. As early as 1 w after implantation, radiographs showed the presence of surface corrosion and small, dense bodies near the original implant, presumably DU. This corrosion from the surface of the implant continued with time, but did not result in an increasing amount of DU reaching the blood and urine after the first 3 mo. During this 3-mo period, connective tissue capsules formed around the implants, and are hypothesized to have reduced the access of DU to tissue fluids by limiting the

  19. Comportement du carbone aux joints de grains du molybdène

    OpenAIRE

    1994-01-01

    Pas de résumé en anglais; La mise en évidence et l'interprétation du rôle bénéfique du carbone et du rôle néfaste de l'oxygène sur la cohésion intergranulaire du molybdène en l'absence de précipitation visible au MEB constituaient le but de cette étude. Une méthode efficace de purification du molybdène a été mise au point. Les mesures de la concentration intergranulaire de carbone en fonction de la température de carburation et de la teneur volumique ont été effectuées à l'aide d'un spectromè...

  20. DU COTÉ DE CHEZ SOI

    Directory of Open Access Journals (Sweden)

    Marc Smeets

    2013-12-01

    Full Text Available Le voyage en Hollande, au XIXe siècle, s'inscrit dans une longue tradition où résonnent les notions de liberté, tolérance et commerce, mais il acquiert aussi une spécificité étant donné l’importance que prend la figure du « chez soi » : les Pays-Bas, terre d'agrément où le voyageur français se sent à l'aise et où il aimerait, si possible, vivre. Proust, de ce point de vue-là, ne fait rien de neuf quand il rêve dans la Recherche d'une « vie domestique » en terre batave. Les Pays-Bas, pour le voyageur français au XIXe, c'est le home sweet home.

  1. Protein Dynamics in Organic Media at Varying Water Activity Studied by Molecular Dynamics Simulation

    DEFF Research Database (Denmark)

    Wedberg, Nils Hejle Rasmus Ingemar; Abildskov, Jens; Peters, Günther H.J.

    2012-01-01

    In nonaqueous enzymology, control of enzyme hydration is commonly approached by fixing the thermodynamic water activity of the medium. In this work, we present a strategy for evaluating the water activity in molecular dynamics simulations of proteins in water/organic solvent mixtures. The method...... relies on determining the water content of the bulk phase and uses a combination of Kirkwood−Buff theory and free energy calculations to determine corresponding activity coefficients. We apply the method in a molecular dynamics study of Candida antarctica lipase B in pure water and the organic solvents...... methanol, tert-butyl alcohol, methyl tert-butyl ether, and hexane, each mixture at five different water activities. It is shown that similar water activity yields similar enzyme hydration in the different solvents. However, both solvent and water activity are shown to have profound effects on enzyme...

  2. Cirque du Monde as a health intervention

    Science.gov (United States)

    Fournier, Cynthia; Drouin, Mélodie-Anne; Marcoux, Jérémie; Garel, Patricia; Bochud, Emmanuel; Théberge, Julie; Aubertin, Patrice; Favreau, Gil; Fleet, Richard

    2014-01-01

    Abstract Objective To present Cirque du Soleil’s social circus program, Cirque du Monde, to explore its potential as a primary health care tool for family physicians. Data sources A review of the literature in PubMed, the Cochrane Library, PsycINFO, LaPresse, Eureka, Google Scholar, and Érudit using the key words circus, social circus, Cirque du Monde, and Cirque du Soleil; a Montreal-based initiative, Espace Transition, modeled on Cirque du Monde; and personal communication with Cirque du Soleil’s Social Circus Training Advisor. Study selection The first 50 articles or websites identified for each key word in each of the databases were examined on the basis of their titles and abstracts in the case of articles, and on the basis of their titles and page content in the case of websites. Articles and websites that explored an aspect of social circuses or that described an intervention that involved circuses were then retained for analysis. Because all literature on social circuses was searched, no criterion for year of publication was used. Synthesis No articles on the social circus as a health intervention were found. One study on the use of the circus as an intervention in schools was identified. It demonstrated an increase in self-esteem in the children who took part. One study on the use of the circus in a First Nations community was found; it contained nonspecific, qualitative findings. The other articles identified were merely descriptions of social circuses. One website was identified on the use of the social circus to help youth who had been treated in a hospital setting for major psychiatric disorders to re-enter the community. The team in the pediatric psychiatry department at Centre Hospitalier Universitaire Sainte-Justine, the children’s hospital in Montreal, Que, was contacted; they were leading this project, called Espace Transition. The unpublished preliminary findings of its pilot project demonstrate substantial improvements in overall patient

  3. DNA methylation in obesity

    Directory of Open Access Journals (Sweden)

    Małgorzata Pokrywka

    2014-11-01

    Full Text Available The number of overweight and obese people is increasing at an alarming rate, especially in the developed and developing countries. Obesity is a major risk factor for diabetes, cardiovascular disease, and cancer, and in consequence for premature death. The development of obesity results from the interplay of both genetic and environmental factors, which include sedentary life style and abnormal eating habits. In the past few years a number of events accompanying obesity, affecting expression of genes which are not directly connected with the DNA base sequence (e.g. epigenetic changes, have been described. Epigenetic processes include DNA methylation, histone modifications such as acetylation, methylation, phosphorylation, ubiquitination, and sumoylation, as well as non-coding micro-RNA (miRNA synthesis. In this review, the known changes in the profile of DNA methylation as a factor affecting obesity and its complications are described.

  4. Établissements recevant du public

    CERN Document Server

    2014-01-01

    Synthèse pour les installations électriques, des règles de sécurité contre les risques d’incendie et de panique dans les établissements recevant du public (ERP), selon l’arrêté du 25 juin 1980 modifié. L'ouvrage traite à la fois des dispositions communes aux établissements du 1er groupe (1ère à 4ème catégorie), du 2ème groupe (5ème catégorie) et des règles particulières applicables aux différents types d'établissements (structures d'accueil pour personnes âgées ou handicapées, hôtels, magasins de vente, restaurants et débit de boisson, établissements de soins, administration, châpiteaux, etc...) Sont ainsi notamment traités, dans le cadre des dispositions communes aux établissements du 1er groupe, pour les installations électriques normales : les installations des appareils, tableaux et canalisations, les locaux électriques et installation de machines, l'éclairage normal des locaux accessibles au public, le chauffage et la ventilation, l'installation d'eau chaude sanita...

  5. L’internationalisation du roman arabe

    Directory of Open Access Journals (Sweden)

    Dr Dalia Khraibani

    2016-09-01

    Full Text Available La littérature arabe est presque invisible dans l’espace littéraire mondiale pour des raisons diverses. Pourtant, des écrivains réussissent à s’imposer sur la scène littéraire internationale et leurs œuvres deviennent des chefs d’œuvre de la littérature mondiale. Parmi ces écrivains, nous citons Tayeb Saleh qui connaît un succès international surtout avec la parution de son second roman "Saison de migration vers le Nord". Notre étude vise à montrer comment ce roman par son contenu et sa forme, occupe une place de choix dans la littérature mondiale. En effet, nous allons examiner le contexte historique de l’émergence du roman qui joue un rôle dans sa diffusion au niveau mondial. L’une des clés de réussite du roman est la technique narrative qui retient l’haleine du lecteur dès la première page. De plus, le roman répond à l’horizon d’attente du lectorat occidental en représentant des images particulières de la société arabo-africaine qui correspondent aux stéréotypes et clichés du public occidental vis-à-vis des Arabes.

  6. Influence du pH, d'acides aminés et de diverses substances organiques sur la fongitoxicité du pyriméthanil, du glufosinate, du captafol, du cymoxanil et du fenpiclonil vis-à-vis de certaines souches de Botrytis cinerea

    OpenAIRE

    1994-01-01

    L’effet du pyriméthanil, du fenpiclonil, du captafol, du glufosinate et du cymoxanil sur l’élongation des filaments germinatifs des spores de Botrytis cinerea est étudié dans diverses conditions culturales du champignon. Si le fenpiclonil présente un niveau d’activité stable entre pH 3,6 et 7,3, en revanche les autres pesticides voient leur toxicité chuter dans des milieux acides (ex pyriméthanil) ou neutres à faiblement basiques (ex captafol, cymoxanil, glufosinate). L’adjonction d’extrait d...

  7. De Gainsborough à Turner : l'âge d'or du paysage et du portrait anglais dans les collections du musée du Louvre

    OpenAIRE

    Adrien, Muriel

    2015-01-01

    L’exposition De Gainsborough à Turner : l'âge d'or du paysage et du portrait anglais dans les collections du musée du Louvre co-organisée par le Musée du Louvre, le Musée d’Art et d’Archéologie de Valence et le Musée des Beaux-arts de Quimper présentait une sélection de 35 peintures de la collection du Louvre, complétée par 38 dessins du département des Arts Graphiques. Les commissaires de l'exposition étaient : Guillaume Faroult, conservateur en charge des peintures françaises du 18ème siècl...

  8. Apoptosis and DNA Methylation

    Energy Technology Data Exchange (ETDEWEB)

    Meng, Huan X.; Hackett, James A. [MRC Human Genetics Unit, IGMM, Western General Hospital, Edinburgh EH4 2XU (United Kingdom); Nestor, Colm [MRC Human Genetics Unit, IGMM, Western General Hospital, Edinburgh EH4 2XU (United Kingdom); Breakthrough Research Unit, University of Edinburgh, Western General Hospital, Edinburgh EH4 2XU (United Kingdom); Dunican, Donncha S.; Madej, Monika; Reddington, James P. [MRC Human Genetics Unit, IGMM, Western General Hospital, Edinburgh EH4 2XU (United Kingdom); Pennings, Sari [Queen' s Medical Research Institute, University of Edinburgh, Edinburgh EH16 4TJ (United Kingdom); Harrison, David J. [Breakthrough Research Unit, University of Edinburgh, Western General Hospital, Edinburgh EH4 2XU (United Kingdom); Meehan, Richard R., E-mail: Richard.Meehan@hgu.mrc.ac.uk [MRC Human Genetics Unit, IGMM, Western General Hospital, Edinburgh EH4 2XU (United Kingdom); Breakthrough Research Unit, University of Edinburgh, Western General Hospital, Edinburgh EH4 2XU (United Kingdom)

    2011-04-01

    Epigenetic mechanisms assist in maintaining gene expression patterns and cellular properties in developing and adult tissues. The molecular pathology of disease states frequently includes perturbation of DNA and histone methylation patterns, which can activate apoptotic pathways associated with maintenance of genome integrity. This perspective focuses on the pathways linking DNA methyltransferases and methyl-CpG binding proteins to apoptosis, and includes new bioinformatic analyses to characterize the evolutionary origin of two G/T mismatch-specific thymine DNA glycosylases, MBD4 and TDG.

  9. Apoptosis and DNA Methylation

    Directory of Open Access Journals (Sweden)

    Richard R. Meehan

    2011-04-01

    Full Text Available Epigenetic mechanisms assist in maintaining gene expression patterns and cellular properties in developing and adult tissues. The molecular pathology of disease states frequently includes perturbation of DNA and histone methylation patterns, which can activate apoptotic pathways associated with maintenance of genome integrity. This perspective focuses on the pathways linking DNA methyltransferases and methyl-CpG binding proteins to apoptosis, and includes new bioinformatic analyses to characterize the evolutionary origin of two G/T mismatch-specific thymine DNA glycosylases, MBD4 and TDG.

  10. Occurrence of synthetic phenolic antioxidants and transformation products in urban and rural indoor dust.

    Science.gov (United States)

    Liu, Runzeng; Lin, Yongfeng; Ruan, Ting; Jiang, Guibin

    2017-02-01

    In this study, seven synthetic phenolic antioxidant (SPA) analogues were positively found in urban and rural indoor dust samples collected from Shandong province in China, among which the novel 2,4,6-tri-tert-butylphenol (AO 246), 2,6-di-tert-butyl-4-sec-butylphenol (DTBSBP), 2,4-di-tert-butylphenol (DBP) and 4,4'-butylidenebis (2-(1,1-dimethylethyl)-5- methyl-phenol) (AO 44B25) analogues accounted for 29% of total SPA concentrations (∑SPAs). Urban dust showed significantly higher ∑SPA levels (range: 1.56e3 - 2.03e4 ng/g) compared with those in rural indoor dust (668-4.39e3 ng/g, p BHT) was the dominate analogue in the urban indoor dust, which constituted of 74% in ΣSPAs. While, varied composition profiles of SPAs were noticed in rural indoor dust, for instance, AO 246 (46%) and BHT (43%) had similar contributions to ∑SPAs. Three BHT transformation products (TPs) were also detected in most of the urban and rural dust samples (>97%), with individual residue level in the same order: 2,6-di-tert-butyl-1,4-benzoquinone (BHT-Q) > 2,6-di-tert-butyl-4-hydroxy- 4-methyl-2,5-cyclo-hexadienone (BHT-quinol) > 3,5-di-tert-butyl-4-hydroxybenzal-dehyde (BHT-CHO). Geometric mean values of total TP concentrations were 555 ng/g and 131 ng/g for urban and rural indoor dust samples, respectively. A preliminary estimated daily intake calculation at dust ingestion scenario suggested additional concerns might be paid to simultaneous exposure of several SPA analogues and TPs besides current focus on BHT exposure risks. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Radical-scavenging activity of butylated hydroxytoluene (BHT) and its metabolites.

    Science.gov (United States)

    Fujisawa, Seiichiro; Kadoma, Yoshinori; Yokoe, Ichiro

    2004-07-01

    To clarify the radical-scavenging activity of butylated hydroxytoluene (BHT), a food additive, stoichiometric factors (n) and inhibition rate constants (kinh) were determined for 2,6-di-tert-butyl-4-methylphenol (BHT) and its metabolites 2,6-di-tert-butyl-p-benzoquinone (BHT-Q), 3,5-di-tert-butyl-4-hydroxybenzaldehyde (BHA-CHO) and 3,5-di-tert-butyl-4-hydroperoxy-4-methyl-2,5-cyclohexadiene-1-one (BHT-OOH). Values of n and kinh were determined from differential scanning calorimetry (DSC) monitoring of the polymerization of methyl methacrylate (MMA) initiated by 2,2'-azobis(isobutyronitrile) (AIBN) or benzoyl peroxide (BPO) at 70 degrees C in the presence or absence of antioxidants (BHT-related compounds). The n values declined in the order BHT (1-2) > BHT-CHO, BHT-OOH (0.1-0.3) > BHT-Q ( approximately 0). The n value for BHT with AIBN was approximately 1.0, suggesting dimerization of BHT. The kinh values declined in the order BHT-Q ((3.5-4.6) x 10(4) M(-1)s(-1)) > BHT-OOH (0.7-1.9 x 10(4) M(-1)s(-1)) > BHT-CHO ((0.4-1.7 x 10(4) M(-1)s(-1)) > BHT ((0.1-0.2 x 10(4) M(-1)s(-1)). The kinh for metabolites was greater than that for the parent BHT. Growing MMA radicals initiated by BPO were suppressed much more efficiently by BHT or BHT-Q compared with those initiated by AIBN. BHT was effective as a chain-breaking antioxidant.

  12. Analyse énonciative du point du vue, narration et analyse de discours

    Directory of Open Access Journals (Sweden)

    Alain Rabatel

    2007-01-01

    Full Text Available Cet article montre que l’analyse énonciative du point de vue (PDV, en rupture avec la typologie des focalisations de Genette, peut renouveler partiellement la narratologie, à la condition de substituter à l’approche immanentiste du récit une analyse interactionnelle de la narration. L’article présente d’abord l’approche énonciative du PDV, en appui des théories de Ducrot, et, sur cette base, propose diverses modalités de PDV (représenté, raconté, asserté qui donnent corps au point de vue des personnages ou du narrateur en modifiant sensiblement les analyses de Genette. Dans une deuxième partie, l’article envisage le rôle des PDV dans la narration, notamment dans la réévaluation des dimensions cognitive et pragmatique de la mimésis, puis dans les mécanismes inférentiels-interprétatifs, proches du système de sympathie de Jouve, enfin, dans la revalorisation du rôle du narrateur •puisque ce dernier se construit dans le même temps qu’il construit ses personnages.

  13. Science et technologie du collage

    CERN Document Server

    Cognard, Jacques

    2003-01-01

    L'Homme a su coller avant de savoir écrire et compter. Le collage est en effet l'une des premières techniques d'assemblage d'une structure que l'homme ait utilisée, technique qui n'est devenue science qu'au début du 20e siècle avec la fabrication des premières colles synthétiques. Cette science de l'adhésion a considérablement progressé ces dix dernières années et ce livre présente l'état actuel des connaissances en décrivant les progrès considérables réalisés dans la compréhension des phénomènes fondamentaux qui font qu'un collage tient bien et durablement. Après l'exposé des bases scientifiques nécessaires et des modèles théoriques récents, l'auteur introduit la distinction entre collages faibles et collages forts puis expose les difficultés rencontrées dans les cas pratiques, difficultés souvent dues à la complexité de la chimie des surfaces et des réactions surface-polymère. L'ouvrage se termine par la présentation de quelques applications récentes, en particulier dans...

  14. Les métamorphoses du pouvoir

    OpenAIRE

    Adler, Alfred

    2004-01-01

    On sait que la sorcellerie en Afrique peut s'exercer du faible au fort ou l'inverse. Les situations qui sont ici analysées sont celles où les rois ou les chefs sont expressément désignés comme sorciers, soit qu'ils le deviennent du fait même de leur investiture, soit qu'il leur ait fallu le devenir pour accéder au pouvoir et le conserver face à des rivaux usant des mêmes moyens. Quoi qu'il en soit, un roi-sorcier offre une figure paradoxale du pouvoir, et cela doublement : garant de l'...

  15. Au fond de la logique du lieu.

    Directory of Open Access Journals (Sweden)

    Augustin Berque

    2009-03-01

    Full Text Available L’école de Kyôto ( Kyôto gakuha est cette mouvance philosophique, née dans l’entre-deux-guerres, dont le Nihonshi jiten ( Dictionnaire historique du Japon des éditions Iwanami donne la présentation suivante : 1 École centrée sur la Faculté de philosophie de l’Université de Kyôto dans les années Taishô et Shôwa. Elle débuta autour de Nishida Kitarô et de Tanabe Hajime, mais on la connaît plutôt du fait que peu après le début de la guerre du Pacifique, en 1942, ...

  16. Oncoplastie avec conservation mammaire dans le traitement du cancer du sein: à propos de 16 cas

    OpenAIRE

    2015-01-01

    Le cancer du sein est actuellement le cancer le plus fréquent chez la femme, et pose un véritable problème diagnostique et thérapeutique. Le dépistage des lésions à un stade de plus en plus précoce, a permis une extension des indications du traitement conservateur radiochirurgical, qui était initialement limitées aux tumeurs de moins de 3 cm, unifocales, non inflammatoires. Par ailleurs, l'utilisation de traitements préopératoires permet d’étendre les indications du traitement conservateur à ...

  17. Methylated β-Cyclodextrins

    DEFF Research Database (Denmark)

    Schönbeck, Jens Christian Sidney; Westh, Peter; Madsen, Jens Christian

    2011-01-01

    groups at O2 promote complexation by extending the hydrophobic cavity. Like in the case of 2-hydroxypropylated cyclodextrins, the methyl substituents cause an increased release of ordered water from the hydration shell of the bile salts, resulting in a strong increase in both the enthalpy and the entropy...

  18. Methylated β-Cyclodextrins

    DEFF Research Database (Denmark)

    Schönbeck, Jens Christian Sidney; Westh, Peter; Madsen, Jens Christian

    2011-01-01

    groups at O2 promote complexation by extending the hydrophobic cavity. Like in the case of 2-hydroxypropylated cyclodextrins, the methyl substituents cause an increased release of ordered water from the hydration shell of the bile salts, resulting in a strong increase in both the enthalpy and the entropy...

  19. Le Flaubert de Charles Du Bos

    Directory of Open Access Journals (Sweden)

    Jacques Neefs

    2009-01-01

    Full Text Available Charles Du Bos a porté une attention constante à l’œuvre de Flaubert (à l’exclusion de Bouvard et Pécuchet qui semble ne pas exister pour lui, à Madame Bovary et à L’Éducation sentimentale en particulier. La mise en relation de son étude : « Sur le milieu intérieur chez Flaubert », écrite en 1921, avec des textes du Journal de 1923 et de 1937, les rapprochements avec Gogol, Thomas Hardy, Tolstoï, Baudelaire, Henry James qui traversent les écrits de Du Bos, permettent de suivre ce que celui-ci décrit comme « l’expérience spirituelle » d’une matérialité comprise dans la conquête de la triple exigence du Beau, du Vivant et du Vrai. Du Bos décèle la force de l’œuvre de Flaubert dans la « disproportion » du style, et dans la puissance d’absorption qui fait la densité de cette prose, et qui désigne un extraordinaire travail de conversion. L’obscure expérience spirituelle ainsi poursuivie est celle d’un absolu de l’art, expérience paradoxale d’un « mystique qui ne croit à rien » (comme se désignait Flaubert lui-même, que le critique lie à une interrogation sur sa propre conversion.Charles Du Bos devoted an unflagging attention to Flaubert’s work (except for Bouvard et Pécuchet, which, apparently, according to him did not exist, to Madame Bovary and in particular L’Éducation sentimentale. The connection between his essay “Sur le milieu intérieur chez Flaubert”, written in 1921, and extracts from his Journal, from 1923 to 1937, the comparisons with Gogol, Thomas Hardy, Tolstoy, Baudelaire, and Henry James that run through the writings of Du Bos, allow us to follow what he terms “the spiritual experience” of a materiality encompassed in the conquest of the triple demand of the Beautiful, the Living, the Truth. Du Bos detects the power of Flaubert’s work in the “disproportion” of his style, and the power of absorption that forms the density of his prose, showing an

  20. L’ombre du Condor

    Directory of Open Access Journals (Sweden)

    Franck Gaudichaud

    2003-09-01

    Full Text Available Si l’on observe aujourd’hui, avec un regard d’historien, le Cône Sud à la fin des années soixante soixante-dix et que par, la suite, on tourne une page de quelques années, pour fixer la même partie du monde, le constat est sans appel : le sous-continent latino-américain est passé, en général, d’une phase de forte mobilisation et politisation sociale, montée en puissance de partis et organisations révolutionnaires, surgissements de gouvernements populistes de gauche ou progressistes – appelant à une rupture avec l’impérialisme –, à un reflux généralisé du mouvement ouvrier, une ère de violence politique étatisée, la destruction massive de tous les espaces d’expression et de participation démocratiques, l’écrasement physique et idéologique sans relâche des militants et mouvements révolutionnaires, la mise en place de modèles économiques capitalistes dirigistes puis/ou néolibéraux. Que s’est-il passé ? Quel fil conducteur a été rompu et par quels moyens l’Amérique Latine a été conduite à ce reflux des luttes sociales ? Pour répondre à cette question, nous nous contenterons dans cet article de focaliser notre objectif sur un aspect spécifique et essentiel de ce retournement de tendance que vit alors l���Amérique Latine : celui de la mise en place d’un terrorisme d’Etat contre-révolutionnaire transnational, appuyé par l’impérialisme américain, nommé « l’Opération Condor ». Dans cet article, il s’agit de montrer le fonctionnement d’un terrorisme hégémonique dont l’impact sur les sociétés latino-américaines est considérable en termes de destruction du mouvement social, des activités culturelles et de l’ensemble de la vie sociale et politique qui restent marquées, encore aujourd’hui à des degrés divers, par la violence, la peur et l’atomisation structurelle.Si miramos hoy en día, desde una perspectiva histórica, el Cono Sur hacia finales de