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Sample records for tert-butyl ether benzene

  1. Biofiltration and inhibitory interactions of gaseous benzene, toluene, xylene, and methyl tert-butyl ether.

    Science.gov (United States)

    Shim, Eun-Hwa; Kim, Jaisoo; Cho, Kyung-Suk; Ryu, Hee Wook

    2006-05-01

    This study evaluated the individual and combined removal capacities of benzene, toluene, and xylene (B, T, and X) in the presence and absence of methyl tert-butyl ether (MTBE) in a polyurethane biofilter inoculated with a BTX-degrading microbial consortium, and further examined their interactive effects in various mixtures. In addition, Polymerase chain reaction-denaturing gradient gel electrophoresis and phylogenetic analysis of 16S rRNA gene sequences were used to compare the microbial community structures found in biofilters exposed to the various gases and gas mixtures. The maximum individual elimination capacities (MECs) of B, T, and X were 200, 238, and 400 g m(-3) h(-1), respectively. There was no significant elimination of MTBE alone. Addition of MTBE decreased the MECs of B,T, and X to 75, 100, and 300 g m(-3) h(-1), respectively, indicating that benzene was most strongly inhibited by MTBE. When the three gases were mixed (B + T + X), the removal capacities of individual B, T, and X were 50, 90, and 200 g m(-3) h(-1), respectively. These capacities decreased to 40, 50, and 100 g m(-3) h(-1) when MTBE was added to the mix. The MEC of the three-gas mixture (B + T + X) was 340 g m(-3) h(-1), and that of the four-gas mixture was 200 g m(-3) h(-1). Although MTBE alone was not degraded by the biofilter, it could be co-metabolically degraded in the presence of toluene, benzene, or xylene with the MECs of 34, 23, and 14 g m(-3) h(-1), respectively. The microbial community structure analysis revealed that two large groups could be distinguished based on the presence or absence of MTBE, and many of the dominant bacteria in the consortia were closely related to bacteria isolated from aromatic hydrocarbon-contaminated sites and/ or oil wastewaters. These findings provide important new insights into biofiltration and may be used to improve the rational design of biofilters for remediation of petroleum gas-contaminated airstreams according to composition types of mixed

  2. Assessment of genotoxicity of methyl-tert-butyl ether, benzene, toluene, ethylbenzene, and xylene to human lymphocytes using comet assay

    International Nuclear Information System (INIS)

    Chen, Colin S.; Hseu, You C.; Liang, Shih H.; Kuo, J.-Y.; Chen, Ssu. C.

    2008-01-01

    Methyl-tert-butyl ether (MTBE) is a gasoline oxygenate and antiknock additive substituting for lead alkyls currently in use worldwide. Benzene, toluene, ethylbenzene, and xylene (BTEX) are volatile monoaromatic hydrocarbons which are commonly found together in crude petroleum and petroleum products such as gasoline. The aim of this study is to evaluate the genotoxic effects of these tested chemicals in human lymphocytes. Using the alkaline comet assay, we showed that all of the tested chemicals induce DNA damage in isolated human lymphocytes. This effect could follow from the induction of DNA strands breaks. The neutral version of the test revealed that MTBE, benzene, and xylenes induce DNA double-strand breaks at 200 μM. Apart from MTBE, the spin traps, 5,5-dimethyl-pyrroline-N-oxide (DMPO) and N-tert-butyl-α-phenylnitrone (PBN) can decrease the level of DNA damage in BTEX at 200 μM. This indicated that DNA damage could result from the participation of free radicals in DNA-damaging effect, which was further supported by the fact that post-treatment of formamidopyrimidine-DNA glycosylase (Fpg), enzyme recognizing oxidized DNA purines, gave rise to a significant increase in the extent of DNA damage in cells treated with benzene, and xylene at 200 μM. The results obtained suggested that MTBE and BTEX could induce a variety type of DNA damage such as single-strand breaks (SSBs), double-strand breaks (DSBs), and oxidative base modification

  3. 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.

  4. Effect of benzene and ethylbenzene on the transcription of methyl-tert-butyl ether degradation genes of Methylibium petroleiphilum PM1.

    Science.gov (United States)

    Joshi, Geetika; Schmidt, Radomir; Scow, Kate M; Denison, Michael S; Hristova, Krassimira R

    2016-09-01

    Methyl-tert-butyl ether (MTBE) and its degradation by-product, tert-butyl alcohol (TBA), are widespread contaminants detected frequently in groundwater in California. Since MTBE was used as a fuel oxygenate for almost two decades, leaking underground fuel storage tanks are an important source of contamination. Gasoline components such as BTEX (benzene, toluene, ethylbenzene and xylenes) are often present in mixtures with MTBE and TBA. Investigations of interactions between BTEX and MTBE degradation have not yielded consistent trends, and the molecular mechanisms of BTEX compounds' impact on MTBE degradation are not well understood. We investigated trends in transcription of biodegradation genes in the MTBE-degrading bacterium, Methylibium petroleiphilum PM1 upon exposure to MTBE, TBA, ethylbenzene and benzene as individual compounds or in mixtures. We designed real-time quantitative PCR assays to target functional genes of strain PM1 and provide evidence for induction of genes mdpA (MTBE monooxygenase), mdpJ (TBA hydroxylase) and bmoA (benzene monooxygenase) in response to MTBE, TBA and benzene, respectively. Delayed induction of mdpA and mdpJ transcription occurred with mixtures of benzene and MTBE or TBA, respectively. bmoA transcription was similar in the presence of MTBE or TBA with benzene as in their absence. Our results also indicate that ethylbenzene, previously proposed as an inhibitor of MTBE degradation in some bacteria, inhibits transcription of mdpA, mdpJ and bmoAgenes in strain PM1.

  5. Effect of benzene, toluene, ethylbenzene, and p-xylene (BTEX) mixture on biodegradation of methyl tert-butyl ether (MTBE) and tert-butyl alcohol (TBA) by pure culture UC1.

    Science.gov (United States)

    Pruden, Amy; Suidan, Makram

    2004-08-01

    The effect of a BTEX mixture on the biodegradation of methyl tert-butyl ether (MTBE) and its degradation intermediate, tert-butyl alcohol (TBA) was investigated in the pure bacterial culture UC1, which has been identified to be a strain of the known MTBE-degrader PM1 based on greater than 99% 16S rDNA similarity. Several degradation studies were carried out on UC1 at three initial concentration levels of MTBE or TBA: 6-7; 15-17; and 40-45 mg/l, both with and without BTEX present cumulatively at about half of the MTBE or TBA molar mass in the system. The BTEX mixture was observed not to affect either the rate or the degradation lag period of MTBE or TBA degradation, except that the TBA degradation rate actually increased when BTEX was present initially in the highest concentration studies. When serving as the sole substrate, the MTBE degradation rate ranged from 48 +/- 1.2 to 200 +/- 7.0 mg(MTBE)/g(dw) h, and the TBA degradation rate from 140 +/- 18 to 530 +/- 70 mg(TBA)/g(dw) h. When present with BTEX, MTBE and TBA rates ranged from 46 +/- 2.2 to 210 +/- 14 and 170 +/- 28 to 780 +/- 43 mg(TBA)/g(dw) h, respectively. In studies where varying concentrations of TBA were present with 5 mg/l MTBE, both compounds were degraded simultaneously with no obvious preference for either substrate. In the highest concentration study of TBA with 5 mg/l MTBE, BTEX was also observed to increase the ultimate rate of TBA degradation. In addition to exploring the affect of BTEX, this study also provides general insight into the metabolism of MTBE and TBA by pure culture UC1.

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

    Directory of Open Access Journals (Sweden)

    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.

  7. Temperature influence on mixing properties of {ethyl tert-butyl ether (ETBE) + gasoline additives}

    International Nuclear Information System (INIS)

    Gonzalez-Olmos, R.; Iglesias, M.

    2007-01-01

    The densities and ultrasonic velocity of {ethyl tert-butyl ether (ETBE) + (benzene, toluene, ethylbenzene, isooctane, tert-butyl alcohol, and ethanol)} over the temperature range (288.15 to 323.15) K and atmospheric pressure, have been measured over the whole concentration range. The experimental excess volumes and deviation of isentropic compressibilities data have been analysed in terms of different theoretical models. The gathered data improve open literature related to gasoline additives, and help to understand the ETBE volumetric and acoustic trend into different chemical environment

  8. Anaerobic degradation of methyl tert-butyl ether (MTBE) and tert-butyl alcohol (TBA).

    Science.gov (United States)

    Finneran, K T; Lovley, D R

    2001-05-01

    The potential for anaerobic degradation of methyl tert-butyl ether (MTBE) and tert-butyl alcohol (TBA) was investigated in laboratory incubations of sediments from a petroleum-contaminated aquifer and in aquatic sediments. The addition of humic substances (HS) stimulated the anaerobic degradation of MTBE in aquifer sediments in which Fe(III) was available as an electron acceptor. This is attributed to the fact that HS and other extracellular quinones can stimulate the activity of Fe(III)-reducing microorganisms by acting as an electron shuttle between Fe(III)-reducing microorganisms and insoluble Fe(III) oxides. MTBE was not degraded in aquifer sediments without Fe(III) and HS. [14C]-MTBE added to aquatic sediments adapted for anaerobic MTBE degradation was converted to 14CO2 in the presence or absence of HS or the HS analog, anthraquione-2,6-disulfonate. Unamended aquatic sediments produced 14CH4 as well as 14CO2 from [14C]-MTBE. The aquatic sediments also rapidly consumed TBA under anaerobic conditions and converted [14C]-TBA to 14CH4 and 14CO2. An adaptation period of ca. 250-300 days was required prior to the most rapid anaerobic MTBE degradation in both sediment types, whereas TBA was metabolized in the aquatic sediments without a lag. These results demonstrate that, under the appropriate conditions, MTBE and TBA can be degraded in the absence of oxygen. This suggests that it may be possible to design strategies for the anaerobic remediation of MTBE in petroleum-contaminated subsurface environments.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

  11. Sorption of methyl tert-butyl ether (MTBE) and tert-butyl alcohol (TBA) to synthetic resins.

    Science.gov (United States)

    Bi, Erping; Haderlein, Stefan B; Schmidt, Torsten C

    2005-10-01

    Methyl tert-butyl ether (MTBE) is a widely used gasoline oxygenate. Contamination of MTBE and its major degradation product tert-butyl alcohol (TBA) in groundwater and surface water has received great attention. However, sorption affinity and sorption mechanisms of MTBE and TBA to synthetic resins, which can be potentially used in removal of these contaminants from water, in passive sampling, or in enrichment of bacteria, have not been studied systemically. In this study, kinetic and equilibrium sorption experiments (single solute and binary mixtures) on four synthetic resins were conducted. The sorption affinity of the investigated sorbents for MTBE and TBA decreases in the order Ambersorb 563>Optipore L493>Amberlite XAD4>Amberlite XAD7, and all show higher sorption affinity for MTBE than for TBA. Binary experiments with o-xylene, a major compound of gasoline as co-contaminant, imply that all resins preferentially sorb o-xylene over MTBE or TBA, i.e., there is sorption competition. In the equilibrium aqueous concentration (Ceq) range (0.1-139.0 mg/L for MTBE, and 0.01-48.4 mg/L for TBA), experimental and modeling results as well as sorbent characteristics indicate that micropore filling and/or some other type of adsorption process (e.g., adsorption to specific sites of high sorption potential at low concentrations) rather than partitioning were the dominant sorption mechanisms. Optipore L493 has favourable sorption and desorption characteristics, and is a suitable sorbent, e.g., in bacteria enrichment or passive sampling for moderately polar compounds. However, for highly polar compounds such as TBA, Ambersorb 563 might be a better choice, especially in water treatment.

  12. EFFECTS OF STIMULATOR SUBSTANCES ON AEROBIC METHYL TERT-BUTYL ETHER BIODEGRADATION BY MICROBIAL CONSORTIUM

    Directory of Open Access Journals (Sweden)

    M. Farrokhi ، S. Ahmadizad

    2009-04-01

    Full Text Available In this study dissolved humic substances and yeast extract were tested in different concentrations for enhancing methyl tert-butyl ether mineralization by isolated microorganisms from a variety of sources. All experiments were conducted at a constant temperature of 25ºC. Vials of 50 mL and 125 mL volume sealed with Teflon-lined Mini-Nert caps was used for microcosm experiments. In all experiments 1% sodium azide were used as control. Samples of bacterial cultures that metabolize methyl tert-butyl ether have been analysed by direct GC analysis using flame ionization detector. Cultures able to metabolize have been found in activated sludge and soils. These microorganisms weregram-positive bacterium. An aerobic microbial consortium was enriched in laboratory for four months. Methyl tert-butyl ether has been shown to biodegrade under aerobic and co-metabolic conditions. A microbial consortium isolated from activated sludges was identified as Cocobacillus. The concentration of the initial attached biomass was about 0.11 g/L of dry weight. The maximum mineralization rate and beneficial effects of stimulator substances on aerobic biodegradation of methyl tert-butyl ether occurred with the culture by combined concentrations of 500 mg/L of yeast extract and 20 mg/L of peat humic growth support of microbial consortium within 216 h and in presence of high oxygen levels and well mixing conditions. It was shown that adding, peat humic and yeast extract together, had better stimulatory effect on methyl tert-butyl ether biodegradation. Results clearly showed a stimulatory effect on methyl tert-butyl ether consumption higher than 20%. Consortium was capable of degrading concentrations of ≤1000 mg/L, whereas concentrations of >1000 mg/L, were not degraded.

  13. Method for determination of methyl tert-butyl ether and its degradation products in water

    Science.gov (United States)

    Church, C.D.; Isabelle, L.M.; Pankow, J.F.; Rose, D.L.; Tratnyek, P.G.

    1997-01-01

    An analytical method is described that can detect the major alkyl ether compounds that are used as gasoline oxygenates (methyl tert-butyl ether, MTBE; ethyl tert-butyl ether, ETBE; and tert-amyl methyl ether, TAME) and their most characteristic degradation products (tert-butyl alcohol, TBA; tert-butyl formate, TBF; and tert-amyl alcohol, TAA) in water at sub-ppb concentrations. The new method involves gas chromatography (GC) with direct aqueous injection (DAI) onto a polar column via a splitless injector, coupled with detection by mass spectrometry (MS). DAI-GC/MS gives excellent agreement with conventional purge-and-trap methods for MTBE over a wide range of environmentally relevant concentrations. The new method can also give simultaneous identification of polar compounds that might occur as degradation products of gasoline oxygenates, such as TBA, TBF, TAA, methyl acetate, and acetone. When the method was applied to effluent from a column microcosm prepared with core material from an urban site in New Jersey, conversion of MTBE to TBA was observed after a lag period of 35 days. However, to date, analyses of water samples from six field sites using the DAI-GC/MS method have not produced evidence for the expected products of in situ degradation of MTBE.An analytical method is described that can detect the major alkyl ether compounds that are used as gasoline oxygenates (methyl tert-butyl ether, MTBE; ethyl tert-butyl ether, ETBE; and tert-amyl methyl ether, TAME) and their most characteristic degradation products (tert-butyl alcohol, TBA; tert-butyl formate, TBF; and tert-amyl alcohol, TAA) in water at sub-ppb concentrations. The new method involves gas chromatography (GC) with direct aqueous injection (DAI) onto a polar column via a splitless injector, coupled with detection by mass spectrometry (MS). DAI-GC/MS gives excellent agreement with conventional purge-and-trap methods for MTBE over a wide range of environmentally relevant concentrations. The new method

  14. INHALATION EXPOSURE TO METHYL TERT-BUTYL ETHER (MTBE) AND DIBROMOCHLOROMETHANE (DBCM) USING CONTINUOUS BREATH ANALYSIS

    Science.gov (United States)

    The oxygenate methyl tert-butyl ether (MTBE) has been added to gasoline to help meet national ambient air quality standards in those parts of the U.S. that are non-compliant for carbon monoxide. Although MTBE has provided important health benefits in terms of reduced haza...

  15. 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...... bed reactor, was determined using a batch kinetic based approach. The procedure involved modeling of methyl tert-butyl ether removal rates from batch experiments followed by parameter estimations. It was estimated to be 5-14% (w/w) of the measured volatile suspended solids concentration in the reactor....

  16. Percutaneous Dissolution of Gallstones using Methyl Tert-Butyl Ether

    OpenAIRE

    1990-01-01

    Radiolucent cholesterol gallstones can be dissolved rapidly by methyl terc-buryl ether (MTBE) introduced directly into the gallbladder. Percutaneous transhepatic catheter placement is a well established interventional radiology procedure and is the preferred route for MTBE administration. A small number of patients have been treated using nasobiliary placement of a gallbladder catheter. Rapid stirring automatic pump systems allow dissolution of most cholesterol stones, but s...

  17. Development of natural rubber membranes for separation of methyl tert-butyl ether and methanol

    International Nuclear Information System (INIS)

    Nur Azrini Ramlee; Ghazali Mohd Nawawi; Khairul Zaman Dahlan

    2010-01-01

    As a new commercial process, membrane separation raises significant expectations in the process plant of the future and therefore this research was being initiated to develop and characterize pervaporation membrane based on natural rubber (NR). Natural Rubber SMR-L grade which was supplied by Malaysia Rubber Research Institute (MRRI) was used for the development of the membranes via interpenetrating polymer network (IPN) techniques. Polystyrene (PS) was used to modify the natural rubber to further improve their mechanical and chemical properties. The membranes were prepared with various blend ratios of natural rubber, polystyrene and divinyl benzene as cross linker with constant 1 % of dicumyl peroxide as the initiator. The developed membranes were then characterized to study the functional group presence, membranes morphology, crosslink density, tear strength, adsorption of the membranes and pervaporation separation of Methyl-Tert-Butyl-Ether (MTBE) and Methanol. Pervaporation process was conducted by using varies of MTBE concentration 10, 30, 50 and 70 wt % and at differ operation temperature, 25 degree Celsius and 55 degree Celsius. Separation performance of IPN NR/ PS membranes were based on the presented permeation flux and separation factor. Examination through Fourier Transform Infrared Spectroscopy (FTIR), determined crosslink density and tear strength, 6 series of IPN NR/ PS membranes were successfully developed using natural rubber. Observation from Scanning Electron Microscopy (SEM) showed that the membranes were dense and appropriated for the pervaporation process application. From the pervaporation of MTBE and Methanol, IPN NR/ PS membranes of series D4N30 shown low permeation flux of MTBE but high separation factor while D2N70 membranes was vice versa for both temperature of 25 degree Celsius and 55 degree Celsius. (author)

  18. 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.

  19. Overview of technologies for removal of methyl tert-butyl ether (MTBE) from water.

    Science.gov (United States)

    Levchuk, Irina; Bhatnagar, Amit; Sillanpää, Mika

    2014-04-01

    Wide use of methyl tert-butyl ether (MTBE) as fuel oxygenates leads to worldwide environment contamination with this compound basically due to fuel leaks from storage or pipelines. Presence of MTBE in drinking water is of high environmental and social concern. Existing methods for MTBE removal from water have a number of limitations which can be possibly overcome in the future with use of emerging technologies. This work aims to provide an updated overview of recent developments in technologies for MTBE removal from water. Copyright © 2014. Published by Elsevier B.V.

  20. Enhancement of methyl tert-butyl ether degradation by the addition of readily metabolizable organic substrates

    International Nuclear Information System (INIS)

    Chen Dongzhi; Chen Jianmeng; Zhong Weihong

    2009-01-01

    Supplements with readily metabolizable organic substrates were investigated to increase the biomass and enhance degradation of methyl tert-butyl ether (MTBE) due to the low biomass yield of MTBE which has been one of the factors for low-rate MTBE degradation. The influence of various organic substrates on the rate of aerobic degradation of methyl tert-butyl ether (MTBE) by Methylibium petroleiphilum PM1 was investigated, and only yeast extract (YE), beef extract and tryptone exhibited stimulatory effect. With the concentration of each substrate being 100 mg/L, the average MTBE removal rate could increase to 1.29, 1.20 and 1.04 mg/(L h), respectively, in comparison with 0.71 mg/(L h) when carried out in medium without addition. The stimulatory effects of YE addition, as well as induction period required by MTBE degradation, varied dramatically with the storage conditions, pre-culture medium and concentrations of the inoculums. The extent of stimulatory effects of YE might be closely related to the proportion of induction period in the total time of MTBE-degradation. The removal efficiency increased from about 50% to 90.5% with the addition of YE in a packed-bed reactor loaded with calcium alginate immobilized cells.

  1. Use of experimental design for the purge-and-trap-gas chromatography-mass spectrometry determination of methyl tert.-butyl ether, tert.-butyl alcohol and BTEX in groundwater at trace level.

    Science.gov (United States)

    Bianchi, F; Careri, M; Marengo, E; Musci, M

    2002-10-25

    An efficient method for the simultaneous determination of methyl tert.-butyl ether, tert.-butyl alcohol, benzene, toluene, ethylbenzene and xylene isomers in groundwater by purge-and-trap-gas chromatography-mass spectrometry was developed and validated. Experimental design was used to investigate the effects of temperature of extraction, time of extraction and percentage of salt added to the water samples. Regression models and desirability functions were applied to find the experimental conditions providing the highest global extraction yield. Validation was carried out in terms of limits of detection (LOD), limits of quantitation (LOQ), linearity and precision. LOD values ranging from 2.6 to 23 ng l(-1) were achieved, whereas linearity was statistically verified over two orders of magnitude for each compound. Precision was evaluated testing two concentration levels. Good results were obtained both in terms of intra-day repeatability and intermediate precision: RSD% lower than 4.5% at the highest concentration and lower than 13% at the lowest one were calculated for intra-day repeatability. A groundwater sample suspected of contamination by leaking underground petroleum storage tanks was analysed and some of the analytes were detected and quantitated.

  2. 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)

  3. 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)

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

    Directory of Open Access Journals (Sweden)

    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.

  5. 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...

  6. 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

  7. 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

    Alkyl, (CH3)(3)COC(CH3)(2)CH2, and alkyl peroxy, (CH3)(3)COC(CH3)(2)CH2O2, radicals from di-tert-butyl ether (DTBE), have been studied in the gas phase at 296 K. A pulse radiolysis UV absorption technique was used to measure the spectra and kinetics. Absorption cross sections were quantified over...

  8. Degradation of methyl tert-butyl ether by gel immobilized Methylibium petroleiphilum PM1.

    Science.gov (United States)

    Chen, Dongzhi; Chen, Jianmeng; Zhong, Weihong; Cheng, Zhuowei

    2008-07-01

    Cells of Methylibium petroleiphilum PM1 were immobilized in gel beads to degrade methyl tert-butyl ether (MTBE). Calcium alginate, agar, polyacrylamide and polyvinvyl alcohol were screened as suitable immobilization matrices, with calcium alginate demonstrating the fastest MTBE-degradation rate. The rate was accelerated by 1.8-fold when the beads had been treated in physiological saline for 24h at 28 degrees C. MTBE degradation in mineral salts medium (MSM) was accompanied by the increase of biomass. The half-life of MTBE-degradation activity for the encapsulated cells stored at 28 degrees C was about 120 h, which was obviously longer than that of free cells (approximately 36 h). Efficient reusability of the beads up to 30 batches was achieved in poor nutrition solution as compared to only 6 batches in MSM. The immobilized cells could be operated in a packed-bed reactor for degradation of 10 mg L(-1) MTBE in groundwater with more than 99% removal efficiency at hydraulic retention time of 20 min. These results suggested that immobilized cells of PM1 in bioreactor might be applicable to a groundwater treatment system for the removal of MTBE.

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

    Directory of Open Access Journals (Sweden)

    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.

  10. Methyl tert-butyl ether biodegradation by indigenous aquifer microorganisms under natural and artificial oxic conditions

    Science.gov (United States)

    Landmeyer, J.E.; Chapelle, F.H.; Herlong, H.H.; Bradley, P.M.

    2001-01-01

    Microbial communities indigenous to a shallow groundwater system near Beaufort, SC, degraded milligram per liter concentrations of methyl tert-butyl ether (MTBE) under natural and artificial oxic conditions. Significant MTBE biodegradation was observed where anoxic, MTBE-contaminated groundwater discharged to a concrete-lined ditch. In the anoxic groundwater adjacent to the ditch, concentrations of MTBE were > 1 mg/L. Where groundwater discharge occurs, dissolved oxygen (DO) concentrations beneath the ditch exceeded 1.0 mg/L to a depth of 1.5 m, and MTBE concentrations decreased to CO2 in laboratory liquid culture studies, with no accumulation of intermediate compounds. Upgradient of the ditch in the anoxic, MTBE and BTEX-contaminated aquifer, addition of a soluble oxygen release compound resulted in oxic conditions and rapid MTBE biodegradation by indigenous microorganisms. In an observation well located closest to the oxygen addition area, DO concentrations increased from 0.4 to 12 mg/L in <60 days and MTBE concentrations decreased from 20 to 3 mg/L. In the same time period at a downgradient observation well, DO increased from <0.2 to 2 mg/L and MTBE concentrations decreased from 30 to <5 mg/L. These results indicate that microorganisms indigenous to the groundwater system at this site can degrade milligram per liter concentrations of MTBE under natural and artificial oxic conditions.

  11. Enhancement of the Biodegradability of Methyl tert- Butyl Ether (MTBE by Advanced Oxidation

    Directory of Open Access Journals (Sweden)

    Mehraban Sadeghi

    2006-06-01

    Full Text Available The effectiveness of ozone treatment for improving the biodegradability of recalcitrant pollutants has been proved by investigating the ozonation reaction of Methyl tert-Butyl Ether (MTBE as a bioresistant gasoline oxygenate. Laboratory scale experiments have been carried out at room temperature by bubbling for 120 minutes ozonated air (3.4 ppm/min into 3 liter of an alkaline (pH=11.5 aqueous solution (100 mg/L of MTBE. The experimental results indicated that during the ozonation, complete MTBE degradation occurs in 100 minutes and after this time, ozone consumption goes on very slowly. At the end of the ozonation, after 100 minutes, the initial value of COD (256 mg O2/L is 98 and corresponds to a relative removal of about 62%. As for MTBE solution biodegradability expressed as (BOD5 / (COD ratio, during the first 90 minutes, its value regularly increases from lowest 0.01 up to a maximum of 0.68 that corresponds to an ozone consumption of 1.25 mg per each mg of COD initially present in the solution. The research showed that partial degradation of MTBE in the advanced oxidation processes results an increase in its biological degradation. But more oxidation results lower  (BOD5 / (COD ratio. Also the research showed that for idealization of the chemical oxidation conditions of MTBE, it needs to decrease COD to 46-68% before the biological degradation. The experimental results for determining the rate of MTBE removal due to stripping showed that about 14% of MTBE strips out after an hour of sparging with oxygen gas. The fraction of MTBE oxidized and/or striped increases to about 28% (in pH=7 and 70% (in pH=11.5 with ozonation over the same time period.

  12. Whole-genome analysis of the methyl tert-butyl ether-degrading beta-proteobacterium Methylibium petroleiphilum PM1.

    Science.gov (United States)

    Kane, Staci R; Chakicherla, Anu Y; Chain, Patrick S G; Schmidt, Radomir; Shin, Maria W; Legler, Tina C; Scow, Kate M; Larimer, Frank W; Lucas, Susan M; Richardson, Paul M; Hristova, Krassimira R

    2007-03-01

    Methylibium petroleiphilum PM1 is a methylotroph distinguished by its ability to completely metabolize the fuel oxygenate methyl tert-butyl ether (MTBE). Strain PM1 also degrades aromatic (benzene, toluene, and xylene) and straight-chain (C(5) to C(12)) hydrocarbons present in petroleum products. Whole-genome analysis of PM1 revealed an approximately 4-Mb circular chromosome and an approximately 600-kb megaplasmid, containing 3,831 and 646 genes, respectively. Aromatic hydrocarbon and alkane degradation, metal resistance, and methylotrophy are encoded on the chromosome. The megaplasmid contains an unusual t-RNA island, numerous insertion sequences, and large repeated elements, including a 40-kb region also present on the chromosome and a 29-kb tandem repeat encoding phosphonate transport and cobalamin biosynthesis. The megaplasmid also codes for alkane degradation and was shown to play an essential role in MTBE degradation through plasmid-curing experiments. Discrepancies between the insertion sequence element distribution patterns, the distributions of best BLASTP hits among major phylogenetic groups, and the G+C contents of the chromosome (69.2%) and plasmid (66%), together with comparative genome hybridization experiments, suggest that the plasmid was recently acquired and apparently carries the genetic information responsible for PM1's ability to degrade MTBE. Comparative genomic hybridization analysis with two PM1-like MTBE-degrading environmental isolates (approximately 99% identical 16S rRNA gene sequences) showed that the plasmid was highly conserved (ca. 99% identical), whereas the chromosomes were too diverse to conduct resequencing analysis. PM1's genome sequence provides a foundation for investigating MTBE biodegradation and exploring the genetic regulation of multiple biodegradation pathways in M. petroleiphilum and other MTBE-degrading beta-proteobacteria.

  13. Involvement of a novel enzyme, MdpA, in methyl tert-butyl ether degradation in Methylibium petroleiphilum PM1.

    Science.gov (United States)

    Schmidt, Radomir; Battaglia, Vince; Scow, Kate; Kane, Staci; Hristova, Krassimira R

    2008-11-01

    Methylibium petroleiphilum PM1 is a well-characterized environmental strain capable of complete metabolism of the fuel oxygenate methyl tert-butyl ether (MTBE). Using a molecular genetic system which we established to study MTBE metabolism by PM1, we demonstrated that the enzyme MdpA is involved in MTBE removal, based on insertional inactivation and complementation studies. MdpA is constitutively expressed at low levels but is strongly induced by MTBE. MdpA is also involved in the regulation of tert-butyl alcohol (TBA) removal under certain conditions but is not directly responsible for TBA degradation. Phylogenetic comparison of MdpA to related enzymes indicates close homology to the short-chain hydrolyzing alkane hydroxylases (AH1), a group that appears to be a distinct subfamily of the AHs. The unique, substrate-size-determining residue Thr(59) distinguishes MdpA from the AH1 subfamily as well as from AlkB enzymes linked to MTBE degradation in Mycobacterium austroafricanum.

  14. U.S. Geological Survey laboratory method for methyl tert-Butyl ether and other fuel oxygenates

    Science.gov (United States)

    Raese, Jon W.; Rose, Donna L.; Sandstrom, Mark W.

    1995-01-01

    Methyl tert-butyl ether (MTBE) was found in shallow ground-water samples in a study of 8 urban and 20 agricultural areas throughout the United States in 1993 and 1994 (Squillace and others, 1995, p. 1). The compound is added to gasoline either seasonally or year round in many parts of the United States to increase the octane level and to reduce carbon monoxide and ozone levels in the air. The U.S. Geological Survey (USGS) National Water Quality Laboratory (NWQL), near Denver, uses state-of-the-art technology to analyze samples for MTBE as part of the USGS water-quality studies. In addition, the NWQL offers custom analyses to determine two other fuel oxygenates--ethyl tert-butyl ether (ETBE) and tert-amyl methyl ether (TAME). The NWQL was not able to obtain a reference standard for tert-amyl ethyl ether (TAEE), another possible fuel oxygenate (Shelley and Fouhy, 1994, p. 63). The shallow ground-water samples were collected as part of the USGS National Water-Quality Assessment Program. These samples were collected from 211 urban wells or springs and 562 agricultural wells sampled by the USGS in 1993 and 1994. The wells were keyed to specific land-use areas to assess the effects of different uses on ground-water quality (Squillace and others, 1995, p. 2). Ground-water samples were preserved on site to pH less than or equal to 2 with a solution of 1:1 hydrochloric acid. All samples were analyzed at the NWQL within 2 weeks after collection. The purpose of this fact sheet is to explain briefly the analytical method implemented by the USGS for determining MTBE and other fuel oxygenates. The scope is necessarily limited to an overview of the analytical method (instrumentation, sample preparation, calibration and quantitation, identification, and preservation of samples) and method performance (reagent blanks, accuracy, and precision).

  15. Anaerobic degradation of a mixture of MtBE, EtBE, TBA, and benzene under different redox conditions

    NARCIS (Netherlands)

    Waals, van der Marcelle J.; Pijls, Charles; Sinke, Anja J.C.; Langenhoff, Alette A.M.; Smidt, Hauke; Gerritse, Jan

    2018-01-01

    The increasing use of biobased fuels and fuel additives can potentially change the typical fuel-related contamination in soil and groundwater. Anaerobic biotransformation of the biofuel additive ethyl tert-butyl ether (EtBE), as well as of methyl tert-butyl ether (MtBE), benzene, and tert-butyl

  16. 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

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

    International Nuclear Information System (INIS)

    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

    2012-01-01

    Highlights: ► Ethyl tert-butyl ether (ETBE) (>300 mg L −1 ) found in a groundwater (gas-station). ► No significant carbon or hydrogen isotopic fractionation of ETBE along the plume. ► MC-IFP culture degraded ETBE (0.91 mg L −1 h −1 ) and BTEX (0.64 mg L −1 h −1 ). ► A pilot plant (2 m 3 ) inoculated with MC-IFP degraded ETBE in groundwater (15 °C). ► ethB gene (ETBE biodegradation) amplified during bioaugmentation (5 × 10 6 ethB gene copies L −1 ). - Abstract: Ethyl tert-butyl ether (ETBE) was detected at high concentration (300 mg L −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 (2 m 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 .

  18. Detection and Quantification of Methyl tert-Butyl Ether-Degrading Strain PM1 by Real-Time TaqMan PCR

    OpenAIRE

    Hristova, Krassimira R.; Lutenegger, Christian M.; Scow, Kate M.

    2001-01-01

    The fuel oxygenate methyl tert-butyl ether (MTBE), a widely distributed groundwater contaminant, shows potential for treatment by in situ bioremediation. The bacterial strain PM1 rapidly mineralizes and grows on MTBE in laboratory cultures and can degrade the contaminant when inoculated into groundwater or soil microcosms. We applied the TaqMan quantitative PCR method to detect and quantify strain PM1 in laboratory and field samples. Specific primers and probes were designed for the 16S ribos...

  19. [Biodegradation of methyl tert-butyl ether by stabilized immobilized Methylibium petroleiphilum PM1 cells and its biodegradation kinetics analysis].

    Science.gov (United States)

    Cheng, Zhuo-wei; Fu, Ling-xiao; Jiang, Yi-feng; Chen, Jian-meng; Zhang, Rong

    2011-05-01

    Methylibium petroleiphilum PM1, which is capable of degrading methyl tert-butyl ether (MTBE) , was immobilized in calcium alginate gel beads. Several methods were explored to increase the strength of these gel beads. The central composite design analysis indicated that the introduction of 0.2 mol x L(-1) Ca2+ into the crosslinking solution, 1.38 mmol x L(-1) Ca2+ into the growth medium and 0.1% polyethyleneimine (PEI) as the chemical crosslinking agent could increase the stability of the Ca-alginate gel beads with no loss of biodegradation activity. The stabilized immobilized cells could be used 400 h continuously with no breakage and no bioactivity loss. Examination of scanning electron microscope demonstrated that a membrane surrounding the gel beads was formed and the cells could grow and breed well in the stabilized calcium alginate gel beads. Kinetic analysis of the gel bead-degradation indicated that the rate-limiting step was biochemical process instead of intraparticle diffusion process. The diameter of 3 mm affected the biodegradability less while high concentration of PEI induced much more serious mass transfer restraint.

  20. Method detection limit determination and application of a convenient headspace analysis method for methyl tert-butyl ether in water.

    Science.gov (United States)

    O'Neill, Dennis T; Rochette, Elizabeth A; Ramsey, Philip J

    2002-11-15

    Methyl tert-butyl ether (MTBE) is a common groundwater contaminant, introduced to the environment by leaking petroleum storage tanks, urban runoff, and motorized watercraft. In this study. a simplified (static) headspace analysis method was adapted for determination of MTBE in water samples and soil water extracts. The MDL of the headspace method was calculated to be 2.0 microg L(-1) by the EPA single-concentration design method(1) and 1.2 microg L(-1) by a calibration method developed by Hubaux and Vos (Hubaux, A.; Vos, G. Anal. Chem. 1970,42, 849-855). The MDL calculated with the Hubaux and Vos method was favored because it considers both a true positive and a false positive. The static headspace method was applied to analysis of a tap water sample and a monitoring well sample from a gasoline service station, a river sample, and aqueous extracts from soil excavated during removal of a leaking underground storage tank (LUST). The water samples examined in this study had MTTBE concentrations ranging from 6 to 19 microg L(-1). Aqueous extracts of a soil sample taken from the LUST site had 8 microg L(-1) MTBE.

  1. Assessing soil ecotoxicity of methyl tert-butyl ether using earthworm bioassay; closed soil microcosm test for volatile organic compounds

    International Nuclear Information System (INIS)

    An, Youn-Joo

    2005-01-01

    An earthworm bioassay was conducted to assess ecotoxicity in methyl tert-butyl ether (MTBE)-amended soils. Ecotoxicity of MTBE to earthworms was evaluated by a paper contact method, natural field soil test, and an OECD artificial soil test. All tests were conducted in closed systems to prevent volatilization of MTBE out of test units. Test earthworm species were Perionyx excavatus and Eisenia andrei. Mortality and abnormal morphology of earthworms exposed to different concentrations of MTBE were examined. MTBE was toxic to both earthworm species and the severity of response increased with increasing MTBE concentrations. Perionyx excavatus was more sensitive to MTBE than Eisenia andrei in filter papers and two different types of soils. MTBE toxicity was more severe in OECD artificial soils than in field soils, possibly due to the burrowing behavior of earthworms into artificial soils. The present study demonstrated that ecotoxicity of volatile organic compounds such as MTBE can be assessed using an earthworm bioassay in closed soil microcosm with short-term exposure duration. - Earthworm bioassay can be a good protocol to assess soil ecotoxicity of volatile organic compounds such as MTBE

  2. 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.

  3. 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...... 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....

  4. Gene mdpC plays a regulatory role in the methyl-tert-butyl ether degradation pathway of Methylibium petroleiphilum strain PM1.

    Science.gov (United States)

    Joshi, Geetika; Schmidt, Radomir; Scow, Kate M; Denison, Michael S; Hristova, Krassimira R

    2015-04-01

    Among the few bacteria known to utilize methyl tert-butyl ether (MTBE) as a sole carbon source, Methylibium petroleiphilum PM1 is a well-characterized organism with a sequenced genome; however, knowledge of the genetic regulation of its MTBE degradation pathway is limited. We investigated the role of a putative transcriptional activator gene, mdpC, in the induction of MTBE-degradation genes mdpA (encoding MTBE monooxygenase) and mdpJ (encoding tert-butyl alcohol hydroxylase) of strain PM1 in a gene-knockout mutant mdpC(-). We also utilized quantitative reverse transcriptase PCR assays targeting genes mdpA, mdpJ and mdpC to determine the effects of the mutation on transcription of these genes. Our results indicate that gene mdpC is involved in the induction of both mdpA and mdpJ in response to MTBE and tert-butyl alcohol (TBA) exposure in PM1. An additional independent mechanism may be involved in the induction of mdpJ in the presence of TBA. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  5. Fatty acid methyl esters synthesis from non-edible vegetable oils using supercritical methanol and methyl tert-butyl ether

    International Nuclear Information System (INIS)

    Lamba, Neha; Modak, Jayant M.; Madras, Giridhar

    2017-01-01

    Highlights: • FAMEs were synthesized from non-edible oils using supercritical MeOH and MTBE. • Effect of time, temperature, pressure and molar ratio on conversions was studied. • Rate constants of reaction with methanol and MTBE differ by an order of magnitude. • Non-catalytic supercritical reactions are one order faster than acid catalyzed synthesis. - Abstract: Fatty acid methyl esters (FAMEs) are useful as biodiesel and have environmental benefits compared to conventional diesel. In this study, these esters were synthesized non-catalytically from non-edible vegetable oils: neem oil and mahua oil with two different methylating agents: methanol and methyl tert-butyl ether (MTBE). The effects of temperature, pressure, time and molar ratio on the conversion of triglycerides were studied. The temperature was varied in the range of 523–723 K with molar ratios upto 50:1 and a reaction time of upto 150 min. Conversion of neem and mahua oil to FAMEs with supercritical methanol was found to be 83% in 15 min and 99% in 10 min, respectively at 698 K. Further, a conversion of 46% of mahua oil and 59% of neem oil was obtained in 15 min at 723 K using supercritical MTBE. The rate constants evaluated using pseudo first order reaction kinetics were in the range of 4.7 × 10"−"6 to 1.0 × 10"−"3 s"−"1 for the investigated range of temperatures. The activation energies obtained were in the range of 62–113 kJ/mol for the reaction systems investigated. The supercritical synthesis was found to be superior to the catalytic synthesis of the corresponding FAMEs.

  6. Whole-Genome Analysis of the Methyl tert-Butyl Ether-Degrading Beta-Proteobacterium Methylibium petroleiphilum PM1▿ †

    Science.gov (United States)

    Kane, Staci R.; Chakicherla, Anu Y.; Chain, Patrick S. G.; Schmidt, Radomir; Shin, Maria W.; Legler, Tina C.; Scow, Kate M.; Larimer, Frank W.; Lucas, Susan M.; Richardson, Paul M.; Hristova, Krassimira R.

    2007-01-01

    Methylibium petroleiphilum PM1 is a methylotroph distinguished by its ability to completely metabolize the fuel oxygenate methyl tert-butyl ether (MTBE). Strain PM1 also degrades aromatic (benzene, toluene, and xylene) and straight-chain (C5 to C12) hydrocarbons present in petroleum products. Whole-genome analysis of PM1 revealed an ∼4-Mb circular chromosome and an ∼600-kb megaplasmid, containing 3,831 and 646 genes, respectively. Aromatic hydrocarbon and alkane degradation, metal resistance, and methylotrophy are encoded on the chromosome. The megaplasmid contains an unusual t-RNA island, numerous insertion sequences, and large repeated elements, including a 40-kb region also present on the chromosome and a 29-kb tandem repeat encoding phosphonate transport and cobalamin biosynthesis. The megaplasmid also codes for alkane degradation and was shown to play an essential role in MTBE degradation through plasmid-curing experiments. Discrepancies between the insertion sequence element distribution patterns, the distributions of best BLASTP hits among major phylogenetic groups, and the G+C contents of the chromosome (69.2%) and plasmid (66%), together with comparative genome hybridization experiments, suggest that the plasmid was recently acquired and apparently carries the genetic information responsible for PM1's ability to degrade MTBE. Comparative genomic hybridization analysis with two PM1-like MTBE-degrading environmental isolates (∼99% identical 16S rRNA gene sequences) showed that the plasmid was highly conserved (ca. 99% identical), whereas the chromosomes were too diverse to conduct resequencing analysis. PM1's genome sequence provides a foundation for investigating MTBE biodegradation and exploring the genetic regulation of multiple biodegradation pathways in M. petroleiphilum and other MTBE-degrading beta-proteobacteria. PMID:17158667

  7. 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

  8. Volumetric Behaviour of the Ternary System (Methyl Tert-butyl ether + Methylbenzene + Butan-1-ol) and Its Binary sub-System (Methyl Tert-Butyl Ether + Butan-1-ol) within the Temperature Range (298.15–328.15) K

    Czech Academy of Sciences Publication Activity Database

    Morávková, Lenka; Troncoso, J.; Škvorová, M.; Havlica, Jaromír; Petrus, P.; Sedláková, Zuzana

    2015-01-01

    Roč. 90, NOV 2015 (2015), s. 59-70 ISSN 0021-9614 R&D Projects: GA ČR(CZ) GAP105/12/0664; GA MŠk(CZ) LD14094 Grant - others:GNIL(IT) 408 REGALIs (CN2012/120) Institutional support: RVO:67985858 Keywords : methylbenzene * density * methyl-tert-butyl ether Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 2.196, year: 2015

  9. Isolate PM1 populations are dominant and novel methyl tert-butyl ether-degrading bacterial in compost biofilter enrichments.

    Science.gov (United States)

    Bruns, M A; Hanson, J R; Mefford, J; Scow, K M

    2001-03-01

    The gasoline additive MTBE, methyl tert-butyl ether, is a widespread and persistent groundwater contaminant. MTBE undergoes rapid mineralization as the sole carbon and energy source of bacterial strain PM1, isolated from an enrichment culture of compost biofilter material. In this report, we describe the results of microbial community DNA profiling to assess the relative dominance of isolate PM1 and other bacterial strains cultured from the compost enrichment. Three polymerase chain reaction (PCR)-based profiling approaches were evaluated: denaturing gradient gel electrophoresis (DGGE) analysis of 230 bp 16S rDNA fragments; thermal gradient gel electrophoresis (TGGE) analysis of 575 bp 16S rDNA fragments; and non-denaturing polyacrylamide gel electrophoresis of 300-1,500 bp fragments containing 16S/23S ribosomal intergenic transcribed spacer (ITS) regions. Whereas all three DNA profiling approaches indicated that PM1-like bands predominated in mixtures from MTBE-grown enrichments, ITS profiling provided the most abundant and specific sequence data to confirm strain PM1's presence in the enrichment. Moreover, ITS profiling did not produce non-specific PCR products that were observed with T/DGGE. A further advantage of ITS community profiling over other methods requiring restriction digestion (e.g. terminal restriction fragment length polymorphisms) was that it did not require an additional digestion step or the use of automated sequencing equipment. ITS bands, excised from similar locations in profiles of the enrichment and PM1 pure culture, were 99.9% identical across 750 16S rDNA positions and 100% identical across 691 spacer positions. BLAST comparisons of nearly full-length 16S rDNA sequences showed 96% similarity between isolate PM1 and representatives of at least four different genera in the Leptothrix subgroup of the beta-Proteobacteria (Aquabacterium, Leptothrix, Rubrivivax and Ideonella). Maximum likelihood and parsimony analyses of 1,249 nucleotide

  10. Isothermal (vapor + liquid) equilibria and excess enthalpy data of {1-hexene + methyl butyl ether (MBE)} and {1-hexene + methyl tert-butyl ether (MTBE)} binary systems at several temperatures

    International Nuclear Information System (INIS)

    Hani, Rachida; Solimando, Roland; Negadi, Latifa; Jose, Jacques; Ait Kaci, Ahmed

    2012-01-01

    Highlights: ► Vapor pressures of (1-hexene + methyl butyl ether) or (1-hexene + methyl tert-butyl ether) are reported between (263 and 363) K. ► The two mixtures exhibit positive G E . ► Additionally, molar excess enthalpies, H E , for the two binary systems have been measured at 303.15. - Abstract: The vapor pressures of {1-hexene + methyl butyl ether (MBE)} and {1-hexene + methyl tert-butyl ether (MTBE)} binary mixtures and of the three pure components were measured by means of a static device at temperatures between (263 and 333) K. The data were correlated with the Antoine equation. From these data, excess Gibbs functions were calculated for several constant temperatures and fitted to a third-order Redlich–Kister equation using the Barker’s method. Additionally, molar excess enthalpies, H E , for the two binary systems have been measured at 303.15 K using an isothermal flow calorimeter.

  11. Involvement of a Novel Enzyme, MdpA, in Methyl tert-Butyl Ether Degradation in Methylibium petroleiphilum PM1 ▿

    Science.gov (United States)

    Schmidt, Radomir; Battaglia, Vince; Scow, Kate; Kane, Staci; Hristova, Krassimira R.

    2008-01-01

    Methylibium petroleiphilum PM1 is a well-characterized environmental strain capable of complete metabolism of the fuel oxygenate methyl tert-butyl ether (MTBE). Using a molecular genetic system which we established to study MTBE metabolism by PM1, we demonstrated that the enzyme MdpA is involved in MTBE removal, based on insertional inactivation and complementation studies. MdpA is constitutively expressed at low levels but is strongly induced by MTBE. MdpA is also involved in the regulation of tert-butyl alcohol (TBA) removal under certain conditions but is not directly responsible for TBA degradation. Phylogenetic comparison of MdpA to related enzymes indicates close homology to the short-chain hydrolyzing alkane hydroxylases (AH1), a group that appears to be a distinct subfamily of the AHs. The unique, substrate-size-determining residue Thr59 distinguishes MdpA from the AH1 subfamily as well as from AlkB enzymes linked to MTBE degradation in Mycobacterium austroafricanum. PMID:18791002

  12. Temperature-Induced Desorption of Methyl tert-Butyl Ether Confined on ZSM-5: An In Situ Synchrotron XRD Powder Diffraction Study

    Directory of Open Access Journals (Sweden)

    Elisa Rodeghero

    2017-02-01

    Full Text Available The temperature-induced desorption of methyl tert-butyl ether (MTBE from aqueous solutions onto hydrophobic ZSM-5 was studied by in situ synchrotron powder diffraction and chromatographic techniques. This kind of information is crucial for designing and optimizing the regeneration treatment of such zeolite. The evolution of the structural features monitored by full profile Rietveld refinements revealed that a monoclinic (P21/n to orthorhombic (Pnma phase transition occurred at about 100 °C. The MTBE desorption process caused a remarkable change in the unit-cell parameters. Complete MTBE desorption was achieved upon heating at about 250 °C. Rietveld analysis demonstrated that the desorption process occurred without any significant zeolite crystallinity loss, but with slight deformations in the channel apertures.

  13. Viscosities of binary mixtures of some n-ethoxyethanols with ethyl tert-butyl ether at T = (293.15, 298.15, and 303.15) K

    International Nuclear Information System (INIS)

    Cwiklinska, Aneta; Dzikowski, Tomasz; Szychowski, Dariusz; Kinart, Wojciech J.; Kinart, Cezary M.

    2007-01-01

    Viscosities at T = (293.15, 298.15, and 303.15) K in the binary mixtures of ethyl tert-butyl ether with 2-ethoxyethanol, 2-(2-ethoxyethoxy)ethanol, and 2-[2-(2-ethoxyethoxy)ethoxy]ethanol have been measured over the entire range of mixture compositions. From the experimental data, deviations in the viscosity (Δln η) and excess energies of activation for viscous flow (ΔG *E ) have been calculated. The viscosity data were correlated with equations of Hind et al., Grunberg and Nissan, Auslaender, and McAllister. The results for Δln η and ΔG *E are discussed in terms of intermolecular interactions and structure of studied binary mixtures

  14. Steric/π-electronic insulation of the carbo-benzene ring: dramatic effects of tert-butyl vs phenyl crowns on geometric, chromophoric, redox and magnetic properties.

    Science.gov (United States)

    Listunov, Dymytrii; Duhayon, Carine; Poater, Albert; Mazères, Serge; Saquet, Alix; Maraval, Valérie; Chauvin, Remi

    2018-04-13

    Hexa-tert-butyl-carbo-benzene C18tBu6 and three phenylated counterparts C18tBumPh6-m (m = 4, 2) have been synthesized. The peralkylated version (m = 6) provides experimental access to intrinsic features of the insulated C18 core independently from the influence of π-conjugated substituent. Over the series, structural, spectroscopical and electrochemical properties are compared with those of the hexaphenylated reference (m = 0). Anchoring tBu substituents at the C18 macrocycle is shown to enhance stability and solubility, and to dramatically modify UV-vis absorption and redox properties. Whereas all the carbo-benzenes reported hitherto were obtained as dark-reddish/greenish solids, crystals and solutions of C18tBu6 happen to be yellow (max = 379 nm vs 472 nm for C18Ph6). By comparison to C18Ph6, reduction of C18tBu6 remains reversible but occurs at a twice higher absolute potential (E1/2 = -1.36 V vs -0.72 V). Systematic X-ray diffraction analyses and DFT calculations show that the C18 ring symmetry is the nearest to D6h for m = 6, indicating a maximum geometrical aromaticity. According to calculated nucleus independent chemical shifts, the macrocyclic magnetic aromaticity is also found to be maximum for C18tBu6: NICS(0)=-17.2 ppm, vs -18.0±0.1 ppm for the theoretical references C18H6 and C18F6, and -13.5 ppm for C18Ph6. Accurate correlations of NICS(0) with experimental or calculated maximum UV-vis absorption wavelength max and chemical hardness =ELUMO-EHOMO are evidenced. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Aerobic degradation of methyl tert-butyl ether in a closed symbiotic system containing a mixed culture of Chlorella ellipsoidea and Methylibium petroleiphilum PM1.

    Science.gov (United States)

    Zhong, Weihong; Li, Yixiao; Sun, Kedan; Jin, Jing; Li, Xuanzhen; Zhang, Fuming; Chen, Jianmeng

    2011-01-30

    The contamination of groundwater by methyl tert-butyl ether (MTBE) is one of the most serious environmental problems around the world. MTBE degradation in a closed algal-bacterial symbiotic system, containing a mixed culture of Methylibium petroleiphilum PM1 and Chlorella ellipsoidea, was investigated. The algal-bacterial symbiotic system showed increased MTBE degradation. The MTBE-degradation rate in the mixed culture (8.808 ± 0.007 mg l(-1) d(-1)) was higher than that in the pure bacterial culture (5.664 ± 0.017 mg l(-1) d(-1)). The level of dissolved oxygen was also higher in the mixed culture than that in the pure bacterial culture. However, the improved efficiency of MTBE degradation was not in proportional to the biomass of the alga. The optimal ratio of initial cell population of bacteria to algae was 100:1. An immobilized culture of mixed bacteria and algae also showed higher MTBE degradation rate than the immobilized pure bacterial culture. A mixed culture with algae and PM1 immobilized separately in different gel beads showed higher degradation rate (8.496 ± 0.636 mg l(-1) d(-1)) than that obtained with algae and PM1 immobilized in the same gel beads (5.424 ± 0.010 mg l(-1) d(-1)). Copyright © 2010 Elsevier B.V. All rights reserved.

  16. 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.

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

    Directory of Open Access Journals (Sweden)

    Shanshan Li

    2017-01-01

    Full Text Available 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.

  18. 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.

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

    International Nuclear Information System (INIS)

    Bombach, Petra; a, E-09001 Burgos (Spain))" data-affiliation=" (Kuvier the Biotech Company S.L., Ctra. N-I, p.k. 234–P.E. INBISA 23a, E-09001 Burgos (Spain))" >Nägele, Norbert; Rosell, Mònica; Richnow, Hans H.; Fischer, Anko

    2015-01-01

    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 [ 13 C 6 ]-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

  20. The rapid detection of methyl tert-butyl ether (MtBE) in water using a prototype gas sensor system.

    Science.gov (United States)

    de Lacy Costello, B P J; Sivanand, P S; Ratcliffe, N M; Reynolds, D M

    2005-01-01

    The gasoline additive Methyl-tertiary-Butyl Ether (MtBE) is the second most common contaminant of groundwater in the USA and represents an important soil contaminant. This compound has been detected in the groundwater in at least 27 states as a result of leaking underground storage facilities (gasoline storage tanks and pipelines). Since the health effects of MtBE are unclear the potential threat to drinking water supplies is serious. Therefore, the ability to detect MtBE at low levels (ppb) and on-line at high-risk groundwater sites would be highly desirable. This paper reports the use of 'commercial' and metal oxide sensor arrays for the detection of MtBE in drinking and surface waters at low ppb level (microg.L(-1) range). The output responses from some of the sensors were found to correlate well with MtBE concentrations under laboratory conditions.

  1. Measurement of critical temperatures and critical pressures for binary mixtures of methyl tert-butyl ether (MTBE) + alcohol and MTBE + alkane

    International Nuclear Information System (INIS)

    Han, Kewei; Xia, Shuqian; Ma, Peisheng; Yan, Fangyou; Liu, Tao

    2013-01-01

    Highlights: • The critical properties of seven binary mixtures related to gasoline were measured. • The critical properties of the five systems containing MTBE were reported for the first time. • Binary interaction parameters were fitted by experimental data using PR EOS with Wong–Sandler mixing rule. • Redlich–Kister equation was used to correlate the experimental data. -- Abstract: A set of high-pressure view apparatus was designed for determining the critical properties of chemicals. In order to check the reliability of the apparatus, the critical temperatures (T c ) and critical pressures (P c ) of pure n-heptane, cyclohexane, methanol, ethanol, 1-propanol, methyl tert-butyl ether (MTBE), and binary mixture n-hexane + ethanol were measured. The experimental data were in good agreement with the literature data, which proves the reliability of the apparatus used in the work. The critical temperatures and critical pressures of five binary mixtures containing gasoline additive (MTBE + n-heptane, MTBE + cyclohexane, MTBE + methanol, MTBE + ethanol, MTBE + 1-propanol) were measured using the high-pressure view cell with visual observation. The critical temperatures and critical pressures for the five binary mixtures were all reported for the first time. In addition, the critical temperatures and critical pressures of the binary mixture n-heptane + cyclohexane (two of main components in gasoline) were also measured. All the critical lines for the mixtures studied are continuous which connect the critical points of the two pure components, indicating their phase diagrams belong to type I proposed by Scott and van Konynenburg. The critical points of these systems were calculated by the Peng–Robinson equation of state with the Wong–Sandler mixing rule. This model could calculate the critical properties of the mixtures well with the binary interaction parameter k ij obtained by fitting the experimental critical data. And the experimental data were all

  2. Improving the Safety of Lithium-Ion Battery via a Redox Shuttle Additive 2,5-Di- tert-butyl-1,4-bis(2-methoxyethoxy)benzene (DBBB).

    Science.gov (United States)

    Leonet, Olatz; Colmenares, Luis C; Kvasha, Andriy; Oyarbide, Mikel; Mainar, Aroa R; Glossmann, Tobias; Blázquez, J Alberto; Zhang, Zhengcheng

    2018-03-21

    2,5-Di- tert-butyl-1,4-bis(2-methoxyethoxy)benzene (DBBB) is studied as a redox shuttle additive for overcharge protection for a 1.5 Ah graphite/C-LFP lithium-ion pouch cell for the first time. The electrochemical performance demonstrated that the protecting additive remains inert during the extended standard cycling for 4000 cycles. When a 100% overcharge is introduced in the charging protocol, the baseline cell fails rapidly during the first abusive event, whereas the cell containing DBBB additive withstands 700 overcharge cycles with 87% capacity retention and no gas evolution or cell swelling was observed. It is the first time the effectiveness of the DBBB as overcharge protection additive in a large pouch cell format is demonstrated.

  3. Effect of γ radiation on the solution of potassium permanganate complex with di-tert.-butyl-dibenzo-18-crown-6 in benzene

    International Nuclear Information System (INIS)

    Makhlyarchuk, V.V.; Zatonskij, S.V.; Mikhajlenko, I.E.; Saraeva, V.V.

    1987-01-01

    Effect of 60 Co gamma-radiation on benzene containing KMnO 4 solubilized with crown-ether is studied. Radiation was carried out at room temperature with doses up to 28 kGy at dose rate of 3.9 Gy/s. Sharp increase of diphenyl yield and absence of phenylcyclohexadiene (PCH) in radiolysis products points out interaction of permanganate-ion with predecessors of PCH formation. High yield of permanganate decomposition results from reactions with excited molecules of the solvent

  4. Stable carbon and hydrogen isotope analysis of methyl tert-butyl ether and tert-amyl methyl ether by purge and trap-gas chromatography-isotope ratio mass spectrometry: method evaluation and application.

    Science.gov (United States)

    Kujawinski, Dorothea M; Stephan, Manuel; Jochmann, Maik A; Krajenke, Karen; Haas, Joe; Schmidt, Torsten C

    2010-01-01

    In order to monitor the behaviour of contaminants in the aqueous environment effective enrichment techniques often have to be employed due to their low concentrations. In this work a robust and sensitive purge and trap-gas chromatography-isotope ratio mass spectrometry method for carbon and hydrogen isotope analysis of fuel oxygenates in water is presented. The method evaluation included the determination of method detection limits, accuracy and reproducibility of deltaD and delta(13)C values. Lowest concentrations at which reliable delta(13)C values could be determined were 5 microg L(-1) and 28 microg L(-1) for TAME and MTBE, respectively. Stable deltaD values for MTBE and TAME could be achieved for concentrations as low as 25 and 50 microg L(-1). Good long-term reproducibility of delta(13)C and deltaD values was obtained for all target compounds. But deltaD values varying more than 5 per thousand were observed using different thermal conversion tubes. Thus, a correction of deltaD values in the analysis of groundwater samples was necessary to guarantee comparability of the results. The applicability of this method was shown by the analysis of groundwater samples from a gasoline contaminated site. By two dimensional isotope analysis two locations within this site were identified at which anaerobic and aerobic degradation of methyl tert-butyl ether occurred.

  5. Occurrence and temporal variability of methyl tert-butyl ether (MTBE) and other volatile organic compounds in select sources of drinking water : results of the focused survey

    Science.gov (United States)

    Delzer, Gregory C.; Ivahnenko, Tamara

    2003-01-01

    The large-scale use of the gasoline oxygenate methyl tert-butyl ether (MTBE), and its high solubility, low soil adsorption, and low biodegradability, has resulted in its detection in ground water and surface water in many places throughout the United States. Studies by numerous researchers, as well as many State and local environmental agencies, have discovered high levels of MTBE in soils and ground water at leaking underground gasoline-storage-tank sites and frequent occurrence of low to intermediate levels of MTBE in reservoirs used for both public water supply and recreational boating.In response to these findings, the American Water Works Association Research Foundation sponsored an investigation of MTBE and other volatile organic compounds (VOCs) in the Nation's sources of drinking water. The goal of the investigation was to provide additional information on the frequency of occurrence, concentration, and temporal variability of MTBE and other VOCs in source water used by community water systems (CWSs). The investigation was completed in two stages: (1) reviews of available literature and (2) the collection of new data. Two surveys were associated with the collection of new data. The first, termed the Random Survey, employed a statistically stratified design for sampling source water from 954 randomly selected CWSs. The second, which is the focus of this report, is termed the Focused Survey, which included samples collected from 134 CWS source waters, including ground water, reservoirs, lakes, rivers, and streams, that were suspected or known to contain MTBE. The general intent of the Focused Survey was to compare results with the Random Survey and provide an improved understanding of the occurrence, concentration, temporal variability, and anthropogenic factors associated with frequently detected VOCs. Each sample collected was analyzed for 66 VOCs, including MTBE and three other ether gasoline oxygenates (hereafter termed gasoline oxygenates). As part of

  6. Thermodynamic properties of 4-tert-butyl-diphenyl oxide

    International Nuclear Information System (INIS)

    Druzhinina, A.I.; Pimenova, S.M.; Tarazanov, S.V.; Nesterova, T.N.; Varushchenko, R.M.

    2015-01-01

    Highlights: • The sample of the 4-tert-butyl-diphenyl oxide was synthesized and purified. • Heat capacities, energy of combustion, saturation vapor pressures were measured. • The temperature, the enthalpy and the entropy of fusion were determined. • The enthalpy of sublimation at T = 298.15 K was derived. • The main thermodynamic functions and functions of formation were computed. - Abstract: The main thermodynamic functions (changes of the entropy, enthalpy, and Gibbs free energy) and functions of formation at T = 298.15 K of 4-tert-butyl-diphenyl oxide in condensed and ideal gas states were computed on the basis of experimental results obtained. The heat capacities of 4-tert-butyl-diphenyl oxide was measured by vacuum adiabatic calorimetry over the temperature range (8 to 371) K. The temperature, the enthalpy and the entropy of fusion were determined. The energy of combustion of the sample was determined by static-bomb combustion calorimetry. The saturation vapor pressures of the substance were measured by dynamic transpiration method over the temperature and pressure intervals (298 to 325) K and (0.05 to 1.2) Pa. The enthalpy of sublimation at T = 298.15 K was derived. The contribution of O-(2C b ) group (where C b is the carbon atom in a benzene ring) into the absolute entropies of diphenyl oxide derivatives was assessed

  7. γ-aminobutyric acidA (GABAA) receptor regulates ERK1/2 phosphorylation in rat hippocampus in high doses of Methyl Tert-Butyl Ether (MTBE)-induced impairment of spatial memory

    International Nuclear Information System (INIS)

    Zheng Gang; Zhang Wenbin; Zhang Yun; Chen Yaoming; Liu Mingchao; Yao Ting; Yang Yanxia; Zhao Fang; Li Jingxia; Huang Chuanshu; Luo Wenjing; Chen Jingyuan

    2009-01-01

    Experimental and occupational exposure to Methyl Tert-Butyl Ether (MTBE) has been reported to induce neurotoxicological and neurobehavioral effects, such as headache, nausea, dizziness, and disorientation, etc. However, the molecular mechanisms involved in MTBE-induced neurotoxicity are still not well understood. In the present study, we investigated the effects of MTBE on spatial memory and the expression and function of GABA A receptor in the hippocampus. Our results demonstrated that intraventricular injection of MTBE impaired the performance of the rats in a Morris water maze task, and significantly increased the expression of GABA A receptor α1 subunit in the hippocampus. The phosphorylation of ERK1/2 decreased after the MTBE injection. Furthermore, the decreased ability of learning and the reduction of phosphorylated ERK1/2 level of the MTBE-treated rats was partly reversed by bicuculline injected 30 min before the training. These results suggested that MTBE exposure could result in impaired spatial memory. GABA A receptor may play an important role in the MTBE-induced impairment of learning and memory by regulating the phosphorylation of ERK in the hippocampus.

  8. Simulation of methyl tert-butyl ether (MTBE) transport to ground water from immobile sources of gasoline in the vadose zone

    Science.gov (United States)

    Lahvis, M.A.; Rehmann, L.C.

    1999-01-01

    The mathematical model, R-UNSAT, developed to simulate the transport of benzene and MTBE in representative sand and clay hydrogeologic systems was evaluated. The effects on groundwater were simulated for small, chronic-, and single-volume releases of gasoline trapped in unsaturated soil. Hydrocarbon biodegradation was simulated by using a dual Monod-type kinetics model that includes oxygen and the reactive constituents. MTBE was assumed to be non-reactive. For MTBE, infiltration had the greatest effect on transport to groundwater. Infiltration also affected mass losses of MTBE to the atmosphere, particularly, in fine-grained soils. Depth to groundwater and soil type primarily affected travel times of MTBE to groundwater, but could affect mass-loading rates to groundwater if infiltration is insignificant. For benzene, transport to groundwater was significant only if the depth to the water table was groundwater were generally smaller for benzene than for MTBE by more than two orders of magnitude. Thus, water that recharges an aquifer beneath a spill can be enriched in MTBE relative to benzene when compared to the composition of water in equilibrium with gasoline.

  9. Thermodynamic and kinetic analysis of phase separation of temperature-sensitive poly(vinyl methyl ether) in the presence of hydrophobic tert-butyl alcohol

    Czech Academy of Sciences Publication Activity Database

    Velychkivska, Nadiia; Bogomolova, Anna; Filippov, Sergey K.; Starovoytova, Larisa; Labuta, J.

    2017-01-01

    Roč. 295, č. 8 (2017), s. 1419-1428 ISSN 0303-402X R&D Projects: GA ČR(CZ) GC15-10527J Institutional support: RVO:61389013 Keywords : phase separation * coil-globule transition * poly(vinyl methyl ether) Subject RIV: CF - Physical ; Theoretical Chemistry OBOR OECD: Physical chemistry Impact factor: 1.723, year: 2016

  10. Four coordination polymers based on 5-tert-butyl isophthalic acid and rigid bis(imidazol-1yl)benzene linkers: Synthesis, luminescence detection of acetone and optical properties

    International Nuclear Information System (INIS)

    Arıcı, Mürsel; Zafer Yeşilel, Okan; Büyükgüngör, Orhan

    2017-01-01

    detection of acetone. Moreover, thermal and optical properties of the complexes were also studied. - Highlights: • Four new 2D and 3D coordination polymers with 5-tert-butyl isophthalic acid and rigid bis(imidazol-1yl)benzene linkers. • The structural diversity depending on ligands and coordination number of metal centers. • Fluorescent sensor for the detection of acetone.

  11. Four coordination polymers based on 5-tert-butyl isophthalic acid and rigid bis(imidazol-1yl)benzene linkers: Synthesis, luminescence detection of acetone and optical properties

    Energy Technology Data Exchange (ETDEWEB)

    Arıcı, Mürsel, E-mail: marici@ogu.edu.tr [Department of Chemistry, Faculty of Arts and Sciences, Eskişehir Osmangazi University, 26480 Eskişehir (Turkey); Zafer Yeşilel, Okan [Department of Chemistry, Faculty of Arts and Sciences, Eskişehir Osmangazi University, 26480 Eskişehir (Turkey); Büyükgüngör, Orhan [Department of Physics, Faculty of Arts and Sciences, Ondokuz Mayıs University, 55139 Samsun (Turkey)

    2017-05-15

    methanol could be used as a fluorescent sensor for the detection of acetone. Moreover, thermal and optical properties of the complexes were also studied. - Highlights: • Four new 2D and 3D coordination polymers with 5-tert-butyl isophthalic acid and rigid bis(imidazol-1yl)benzene linkers. • The structural diversity depending on ligands and coordination number of metal centers. • Fluorescent sensor for the detection of acetone.

  12. Surface-Initiated Atom Transfer Radical Polymerization of Magnetite Nanoparticles with Statistical Poly(tert-butyl acrylate-poly(poly(ethylene glycol methyl ether methacrylate Copolymers

    Directory of Open Access Journals (Sweden)

    Patcharin Kanhakeaw

    2015-01-01

    Full Text Available This work presented the surface modification of magnetite nanoparticle (MNP with poly[(t-butyl acrylate-stat-(poly(ethylene glycol methyl ether methacrylate] copolymers (P[(t-BA-stat-PEGMA] via a surface-initiated “grafting from” atom transfer radical polymerization (ATRP. Loading molar ratio of t-BA to PEGMA was systematically varied (100 : 0, 75 : 25, 50 : 50, and 25 : 75, resp. such that the degree of hydrophilicity of the copolymers, affecting the particle dispersibility in water, can be fine-tuned. The reaction progress in each step of the synthesis was monitored via Fourier transform infrared spectroscopy (FTIR. The studies in the reaction kinetics indicated that PEGMA had higher reactivity than that of t-BA in the copolymerizations. Gel permeation chromatography (GPC indicated that the molecular weights of the copolymers increased with the increase of the monomer conversion. Transmission electron microscopy (TEM revealed that the particles were spherical with averaged size of 8.1 nm in diameter. Dispersibility of the particles in water was apparently improved when the copolymers were coated as compared to P(t-BA homopolymer coating. The percentages of MNP and the copolymer in the composites were determined via thermogravimetric analysis (TGA and their magnetic properties were investigated via vibrating sample magnetometry (VSM.

  13. Occurrence and implications of methyl tert-butyl ether and gasoline hydrocarbons in ground water and source water in the United States and in drinking water in 12 Northeast and Mid-Atlantic States, 1993-2002

    Science.gov (United States)

    Moran, Michael J.; Zogorski, John S.; Squillace, Paul J.

    2004-01-01

    The occurrence and implications of methyl tert-butyl ether (MTBE) and gasoline hydrocarbons were examined in three surveys of water quality conducted by the U.S. Geological Survey?one national-scale survey of ground water, one national-scale survey of source water from ground water, and one regional-scale survey of drinking water from ground water. The overall detection frequency of MTBE in all three surveys was similar to the detection frequencies of some other volatile organic compounds (VOCs) that have much longer production and use histories in the United States. The detection frequency of MTBE was higher in drinking water and lower in source water and ground water. However, when the data for ground water and source water were limited to the same geographic extent as drinking-water data, the detection frequencies of MTBE were comparable to the detection frequency of MTBE in drinking water. In all three surveys, the detection frequency of any gasoline hydrocarbon was less than the detection frequency of MTBE. No concentration of MTBE in source water exceeded the lower limit of U.S. Environmental Protection Agency's Drinking-Water Advisory of 20 ?g/L (micrograms per liter). One concentration of MTBE in ground water exceeded 20 ?g/L, and 0.9 percent of drinking-water samples exceeded 20 ?g/L. The overall detection frequency of MTBE relative to other widely used VOCs indicates that MTBE is an important concern with respect to ground-water management. The probability of detecting MTBE was strongly associated with population density, use of MTBE in gasoline, and recharge, and weakly associated with density of leaking underground storage tanks, soil permeability, and aquifer consolidation. Only concentrations of MTBE above 0.5 ?g/L were associated with dissolved oxygen. Ground water underlying areas with high population density, ground water underlying areas where MTBE is used as a gasoline oxygenate, and ground water underlying areas with high recharge has a greater

  14. Temperature effect on tert-butyl alcohol (TBA) biodegradation kinetics in hyporheic zone soils.

    Science.gov (United States)

    Greenwood, Mark H; Sims, Ronald C; McLean, Joan E; Doucette, William J

    2007-09-19

    Remediation of tert-butyl alcohol (TBA) in subsurface waters should be taken into consideration at reformulated gasoline contaminated sites since it is a biodegradation intermediate of methyl tert-butyl ether (MTBE), ethyl tert-butyl ether (ETBE), and tert-butyl formate (TBF). The effect of temperature on TBA biodegradation has not been not been published in the literature. Biodegradation of [U 14C] TBA was determined using hyporheic zone soil microcosms. First order mineralization rate constants of TBA at 5 degrees C, 15 degrees C and 25 degrees C were 7.84 +/- 0.14 x 10-3, 9.07 +/- 0.09 x 10-3, and 15.3 +/- 0.3 x 10-3 days-1, respectively (or 2.86 +/- 0.05, 3.31 +/- 0.03, 5.60 +/- 0.14 years-1, respectively). Temperature had a statistically significant effect on the mineralization rates and was modelled using the Arrhenius equation with frequency factor (A) and activation energy (Ea) of 154 day-1 and 23,006 mol/J, respectively. Results of this study are the first to determine mineralization rates of TBA for different temperatures. The kinetic rates determined in this study can be used in groundwater fate and transport modelling of TBA at the Ronan, MT site and provide an estimate for TBA removal at other similar shallow aquifer sites and hyporheic zones as a function of seasonal change in temperature.

  15. 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.

  16. Temperature effect on tert-butyl alcohol (TBA biodegradation kinetics in hyporheic zone soils

    Directory of Open Access Journals (Sweden)

    Sims Ronald C

    2007-09-01

    Full Text Available Abstract Background Remediation of tert-butyl alcohol (TBA in subsurface waters should be taken into consideration at reformulated gasoline contaminated sites since it is a biodegradation intermediate of methyl tert-butyl ether (MTBE, ethyl tert-butyl ether (ETBE, and tert-butyl formate (TBF. The effect of temperature on TBA biodegradation has not been not been published in the literature. Methods Biodegradation of [U 14C] TBA was determined using hyporheic zone soil microcosms. Results First order mineralization rate constants of TBA at 5°C, 15°C and 25°C were 7.84 ± 0.14 × 10-3, 9.07 ± 0.09 × 10-3, and 15.3 ± 0.3 × 10-3 days-1, respectively (or 2.86 ± 0.05, 3.31 ± 0.03, 5.60 ± 0.14 years-1, respectively. Temperature had a statistically significant effect on the mineralization rates and was modelled using the Arrhenius equation with frequency factor (A and activation energy (Ea of 154 day-1 and 23,006 mol/J, respectively. Conclusion Results of this study are the first to determine mineralization rates of TBA for different temperatures. The kinetic rates determined in this study can be used in groundwater fate and transport modelling of TBA at the Ronan, MT site and provide an estimate for TBA removal at other similar shallow aquifer sites and hyporheic zones as a function of seasonal change in temperature.

  17. Di-tert-butyl 2,2′-[(biphenyl-4,4′-diyldioxy]diacetate

    Directory of Open Access Journals (Sweden)

    Qamar Ali

    2010-07-01

    Full Text Available The complete molecule of the title compound, C24H30O6, is generated by a crystallographic inversion centre. In the unique part of the molecule, the four-atom –O–CH2–C(= O–O– chain between the benzene ring and the tert-butyl group assumes a zigzag conformation [O—C—C—O torsion angle = −162.3 (1°].

  18. n-Alkane assimilation and tert-butyl alcohol (TBA) oxidation capacity in Mycobacterium austroafricanum strains.

    Science.gov (United States)

    Lopes Ferreira, Nicolas; Mathis, Hugues; Labbé, Diane; Monot, Frédéric; Greer, Charles W; Fayolle-Guichard, Françoise

    2007-06-01

    Mycobacterium austroafricanum IFP 2012, which grows on methyl tert-butyl ether (MTBE) and on tert-butyl alcohol (TBA), the main intermediate of MTBE degradation, also grows on a broad range of n-alkanes (C2 to C16). A single alkB gene copy, encoding a non-heme alkane monooxygenase, was partially amplified from the genome of this bacterium. Its expression was induced after growth on n-propane, n-hexane, n-hexadecane and on TBA but not after growth on LB. The capacity of other fast-growing mycobacteria to grow on n-alkanes (C1 to C16) and to degrade TBA after growth on n-alkanes was compared to that of M. austroafricanum IFP 2012. We studied M. austroafricanum IFP 2012 and IFP 2015 able to grow on MTBE, M. austroafricanum IFP 2173 able to grow on isooctane, Mycobacterium sp. IFP 2009 able to grow on ethyl tert-butyl ether (ETBE), M. vaccae JOB5 (M. austroaafricanum ATCC 29678) able to degrade MTBE and TBA and M. smegmatis mc2 155 with no known degradation capacity towards fuel oxygenates. The M. austroafricanum strains grew on a broad range of n-alkanes and three were able to degrade TBA after growth on propane, hexane and hexadecane. An alkB gene was partially amplified from the genome of all mycobacteria and a sequence comparison demonstrated a close relationship among the M. austroafricanum strains. This is the first report suggesting the involvement of an alkane hydroxylase in TBA oxidation, a key step during MTBE metabolism.

  19. 5,11,17,23-Tetra-tert-butyl-25,26,27,28-tetrapropynyloxy-2,8,14,20-tetrathiacalix[4]arene

    Directory of Open Access Journals (Sweden)

    Xiang-Gao Meng

    2009-12-01

    Full Text Available The title compound [systematic name: 5,11,17,23-tetra-tert-butyl-25,26,27,28-tetrapropynyloxy-2,8,14,20-tetrathiacalix[4]arene], C52H56O4S4, is an alkylated product bearing four propyne groups at the lower rim of a 5,11,17,23-tetra-tert-butyl-tetrathiacalix[4]arene. The molecule is located on a crystallographic twofold rotation axis, running through two S atoms and perpendicular to the long axis of the molecule. The four propyne groups, located in an alternate fashion above and below the mean plane of the four S atoms, are almost parallel to the calixarene long axis. The dihedral angle between the two crystallographically independent benzene rings is 86.77 (14°. Two tert-butyl groups are disordered over two positions with site occupancies of 0.59 (2 and 0.41 (2.

  20. 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)

  1. 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)

  2. 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 § 21...

  3. Isothermal Vapour-Liquid Equilibria in the Binary and Ternary Systems Composed of tert-Butyl Methyl Ether, 3,3-Dimethyl-2-butanone and 2,2-Dimethyl-1-propanol

    Czech Academy of Sciences Publication Activity Database

    Bernatová, Svatoslava; Pavlíček, Jan; Wichterle, Ivan

    2009-01-01

    Roč. 278, 1-2 (2009), s. 129-134 ISSN 0378-3812 R&D Projects: GA ČR GA104/07/0444 Institutional research plan: CEZ:AV0Z40720504 Keywords : alcohol * ether * ketone Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.857, year: 2009

  4. Di-tert-butyl 2,2′-(biphenyl-2,2′-diyldioxydiacetate

    Directory of Open Access Journals (Sweden)

    Qamar Ali

    2008-08-01

    Full Text Available The title compound, C24H30O6, does not exhibit π–π interactions due to the steric effect of the bulky tert-butyl groups present in the molecule. The presence of these groups at the 2 and 2′ positions hinders the free motion of the benzene rings relative to each other, causing them to adopt an antiperiplanar arrangement. The benzene rings are twisted by just under 50.96 (17° with respect to each other. The carbonyl groups within the molecule are directed in different directions, one towards the biphenyl group and the other away from it. The molecules are linked together by C=O...H—C hydrogen bonds.

  5. Four coordination polymers based on 5-tert-butyl isophthalic acid and rigid bis(imidazol-1yl)benzene linkers: Synthesis, luminescence detection of acetone and optical properties

    Science.gov (United States)

    Arıcı, Mürsel; Zafer Yeşilel, Okan; Büyükgüngör, Orhan

    2017-05-01

    Four coordination polymers including, [Co(μ-Htbip)2(μ-dib)]n (1), [Co(μ-tbip)(μ-dmib)0.5]n (2), [Zn2(μ-tbip)(μ3-tbip)(μ-dmib)1.5]n (3) and [Cd(μ3-tbip)(μ-dib)0.5 (H2O)]n (4) (tbip: 5-tert-butylisophthalate, dib: 1,4-bis(imidazol-1yl)benzene, dmib: 1,4-bis(imidazol-1yl)-2,5-dimethylbenzene), were hydrothermally synthesized and characterized by elemental analysis, IR spectra, single crystal and powder X-ray diffraction and thermal analysis (TG/DTA). The structural diversity is observed depending on ligands and coordination number of metal centers in the synthesized complexes. The tbip ligand displayed five different coordination modes in its complexes. In 1 and 2, complex 1 is 3D framework with the dia topology while complex 2 has 2D structure with the sql topology depending on coordination geometries of Co ions. Complex 3 is 3D framework with the fsh 4,6-conn topology and complex 4 has 2D 4-connected sql topology. Photoluminescent properties of complex 3 dispersed in various organic solvents were investigated and the results showed that 3 dispersed in methanol could be used as a fluorescent sensor for the detection of acetone. Moreover, thermal and optical properties of the complexes were also studied.

  6. tert-Butyl 2-(4-nitrophenoxyacetate

    Directory of Open Access Journals (Sweden)

    Qamar Ali

    2011-02-01

    Full Text Available In the title molecule, C12H15NO5, the nitrophenoxy portion is approximately planar (r.m.s. deviation = 0.034 Å and makes an angle of 84.8 (1° with respect to the –CH2–C(=O–O–C fragment. In the crystal, π–π stacking is observed between nearly parallel benzene rings of adjacent molecules, the centroid–centroid distance being 3.6806 (10 Å. Weak intermolecular C—H...O hydrogen bonding is present in the crystal structure.

  7. Product analyses and kinetic studies on gas phase oxidation of the fuel additive ethyl tert-butyl ether and its products; Produktanalysen und Kinetikuntersuchungen der Gasphasenoxidation des Kraftstoffadditivs Ethyl-tert-butylether und seiner Produkte

    Energy Technology Data Exchange (ETDEWEB)

    Becker, K H; Thuener, L

    1997-04-01

    The widespread use of the additive ETBE in gasoline leads to an increased release of this compound into the atmosphere via evaporation or exhaust fumes. In order to determine the influence of this additive on trace gas cycles it is first necessary to carry out studies on the degradation mechanisms and pertinent kinetic properties of this substance. The aim of the present study was to examine the degradation mechanisms of the fuel additive t-butyl ethyl ether under atmospheric conditions. The reactions of the main degradation products (t-butyl formiate and t-butyl acetate, together ca. 80%) were also studied in order to obtain as complete a picture of the degradation paths as possible. This was to permit an assessment of the influence of ETBE and its products on tropospheric trace gas cycles and ozone formation. [Deutsch] Bei haeufigem Zusatz von ETBE in Benzin wird diese Verbindung durch Verdampfung oder als Abgas verstaerkt in die Atmosphaere abgegeben. Um den Einfluss des Additivs auf die Spurengas-Kreislaeufe zu bestimmen, sind daher Untersuchungen noetig, um die Abbau-Mechanismen und die zugehoerigen kinetischen Daten zu ermitteln. Das Ziel dieser Arbeit ist die Untersuchung der Abbaumechanismen des Kraftstoffadditivs t-Butylethylether unter atmosphaerischen Bedingungen. Fuer eine moeglichst vollstaendige Analyse des Abbauweges werden auch die Reaktionen der Hauptabbauprodukte (t-Butylformiat und t-Butylacetat, zusammen etwa 80%) untersucht. Dadurch soll der Einfluss auf troposphaerische Spurengas-Kreislaeufe und auf die Ozonbildung von ETBE und seinen Produkten abgeschaetzt werden. (orig./SR)

  8. Design and Control of Glycerol-tert-Butyl Alcohol Etherification Process

    Directory of Open Access Journals (Sweden)

    Elena Vlad

    2012-01-01

    Full Text Available Design, economics, and plantwide control of a glycerol-tert-butyl alcohol (TBA etherification plant are presented. The reaction takes place in liquid phase, in a plug flow reactor, using Amberlyst 15 as a catalyst. The products' separation is achieved by two distillation columns where high-purity ethers are obtained and a section involving extractive distillation with 1,4-butanediol as solvent, which separates TBA from the TBA/water azeotrope. Details of design performed in AspenPlus and an economic evaluation of the process are given. Three plantwide control structures are examined using a mass balance model of the plant. The preferred control structure fixes the fresh glycerol flow rate and the ratio glycerol + monoether : TBA at reactor-inlet. The stability and robustness in the operation are checked by rigorous dynamic simulation in AspenDynamics.

  9. Degradation of methyl-tert-butyl ether (MTBE)

    Czech Academy of Sciences Publication Activity Database

    Cajthaml, Tomáš; Baldrian, Petr; Stoychev, I.; Nerud, František

    2004-01-01

    Roč. 53, - (2004), s. 208-209 ISSN 0964-8305. [International Bideterioration and Biodegradation Symposium /12./. Praha, 14.07.2002-18.07.2002] R&D Projects: GA MŠk LN00B030 Institutional research plan: CEZ:AV0Z5020903 Keywords : mtbe Subject RIV: EE - Microbiology, Virology Impact factor: 0.835, year: 2004

  10. An investigation of 2,5-di-tertbutyl-1,4-bis(methoxyethoxy)benzene in ether-based electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Su, Liang; Ferrandon, Magali; Barton, John L.; de la Rosa, Noel Upia; Vaughey, John T.; Brushett, Fikile R.

    2017-08-01

    The identification and development of conductive electrolytes with high concentrations of redox active species is key to realizing energy-dense nonaqueous flow batteries. Herein, we explore the use of ether solvents (1,3-dioxolane (DOL), 1,2-dimethoxyethane (DME), diethylene glycol dimethyl ether (DEGDME), and tetraethylene glycol dimethyl ether (TEGDME)) as the basis for redox electrolytes containing a lithium ion supporting salt (LiBF4 or LiTFSI) and 2,5-di-tert-butyl-1,4-bis(2-methoxyethoxy)benzene (DBBB) as an active material. An automated high-throughput platform is employed to screen various electrolyte compositions by measuring solution conductivity and solute solubility as a function of solvent and salt type, component concentration, and temperature. Subsequently, the electrochemical and transport properties of select redox electrolytes are characterized by cyclic voltammetry using glassy carbon disk electrodes and by linear sweep voltammetry using carbon fiber ultramicroelectrodes. In general, improvements in electrolyte conductivity and solute solubility are observed with ether-based formulations as compared to previously reported propylene carbonate (PC)-based formulations. In particular, the addition of DOL to a DME-based electrolyte increases the conductivity and decreases the temperature for solubilization at high LiTFSI and DBBB concentrations. The redox behavior of DBBB remains consistent across the range of concentrations tested while the diffusion coefficient scales with changes in solution viscosity.

  11. Synthesis of 4-tert-butyl-1,1-dimethylindan and 7-tert-Butyl-3,3-dimethyl-1-indanone and a comparison of isomers

    International Nuclear Information System (INIS)

    Eisenbraun, E.J.; Harms, W.M.; Paraniswamy, V.A.; Chen, H.H.; Porcaro, P.J.; Wood, T.F.; Chien, M.

    1982-01-01

    4-tert-Butyl-1,1-dimethylindan was synthesized to help establish the identity of products (5- and 6-tert-butyl-1,1-dimethylindan as minor and major products, respectively) from the sulfuric acid catalyzed condensation of tert-butylbenzene and isoprene. NMR ( 1 H and 13 C) studies of these hydrocarbons and their corresponding indanones, obtained through chromic acid oxidation, provided structural proof. Gated decoupling experiments were crucial to complete assignment

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

    KAUST Repository

    Xie, Yihui; Moreno Chaparro, Nicolas; Calo, Victor M.; Cheng, Hong; Hong, Pei-Ying; Sougrat, Rachid; Behzad, Ali Reza; Tayouo Djinsu, Russell; Nunes, Suzana Pereira

    2016-01-01

    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.

  13. 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.

  14. Microbial community composition during anaerobic mineralization of tert-butyl alcohol (TBA) in fuel-contaminated aquifer material.

    Science.gov (United States)

    Wei, Na; Finneran, Kevin T

    2011-04-01

    Anaerobic mineralization of tert-butyl alcohol (TBA) and methyl tert-butyl ether (MTBE) were studied in sediment incubations prepared with fuel-contaminated aquifer material. Microbial community compositions in all incubations were characterized by amplified ribosomal DNA restriction analysis (ARDRA). The aquifer material mineralized 42.3±9.9% of [U-(14)C]-TBA to 14CO2 without electron acceptor amendment. Fe(III), sulfate, and Fe(III) plus anthraquinone-2,6-disulfonate addition also promoted U-[14C]-TBA mineralization at levels similar to those of the unamended controls. Nitrate actually inhibited TBA mineralization relative to unamended controls. In contrast to TBA, [U-(14)C]-MTBE was not significantly mineralized in 400 days regardless of electron acceptor amendment. Microbial community analysis indicated that the abundance of one dominant clone group correlated closely with anaerobic TBA mineralization. The clone was phylogenetically distinct from known aerobic TBA-degrading microorganisms, Fe(III)- or sulfate-reducing bacteria. It was most closely associated with organisms belonging to the alphaproteobacteria. Microbial communities were different in MTBE and TBA amended incubations. Shannon indices and Simpson indices (statistical community comparison tools) both demonstrated that microbial community diversity decreased in incubations actively mineralizing TBA, with distinct "dominant" clones developing. These data contribute to our understanding of anaerobic microbial transformation of fuel oxygenates in contaminated aquifer material and the organisms that may catalyze the reactions.

  15. 3,3′-Di-tert-butyl-1,1′-[1,3-phenylenebis(methylene]diurea

    Directory of Open Access Journals (Sweden)

    Md. Alamgir Hossain

    2010-03-01

    Full Text Available The title compound, C18H30N4O2, contains two tert-butyl urea groups, each connected to a benzene ring though a methylene group. One of the groups occupies a position almost normal to the aromatic plane with a C—N—C—C torsion angle of −94.4 (4°, while the other is considerably twisted from the ring with a C—N—C—C torsion angle of −136.1 (4°. In the crystal, pairs of molecules are connected to each other, forming centrosymmetric dimers in which two NH groups of one molecule act as hydrogen-bond donors to one carbonyl O atom of the other molecule. The dimers are linked into sheets parallel to (100 by N—H...O hydrogen bonds involving the remaining N—H and C=O groups.

  16. Reaction of biscyclopentadienyl molybdendihalides with tert.-butyl hydroperoxide and its using for cyclohexene epoxidation

    International Nuclear Information System (INIS)

    Aleksandrov, Yu.A.; Fomin, V.M.; Kolmakov, A.O.

    1983-01-01

    As a result of reactions of biscyclopentadienyl molybden-dihalides (Cp 2 MoX 2 , X=Cl, Br or I) with tert.-butyl hydroperoxide, tert.-butylperoxides of biscyclopentadienyl molybdendichloride and-dibromide are synthesized for the first time, which are characterized by physico-chemical properties. Cyclohexene in the reaction mixture of Cp 2 MoX 2 with tert -butyl hydroperoxide is oxidated to form cyclohexene oxide, the reaction proceeding at a high rate and with a quantitative yield. Tert.-butylperoxide of biscyclopentadienyl molybdendihalide is responsible for the cyclohexene epoxidation reaction. The schemes for the mechanism of Cp 2 MoX 2 reactions with tert.-butyl hydroperoxide in the absence and presence of olefine are suggested

  17. Continuous synthesis of tert.-butyl peroxypivalate using a single channel micro reactor equipped with orifices as emulsification units

    NARCIS (Netherlands)

    Illg, T.; Hessel, V.; Löb, P.; Schouten, J.C.

    2011-01-01

    The two-step synthesis of tert-butyl peroxypivalate is performed in a single-channel microreactor. The first step, the deprotonation of tert-butyl hydroperoxide, is done in a simple mixer tube setup. The residence time section for the second reaction step is equipped with orifices for interfacial

  18. Atomic Force Microscopy Based Thermal Lithography of Poly(tert-butyl acrylate) Block Copolymer Films for Bioconjugation

    NARCIS (Netherlands)

    Duvigneau, Joost; Schönherr, Holger; Vancso, Gyula J.

    2008-01-01

    In this paper, we report on the local thermal activation of thin polymer films for area-selective surface chemical modification on micrometer and nanometer length scales. The thermally induced activation of tert-butyl ester moieties in polystyrene-block-poly(tert-butyl acrylate) (PS-b-PtBA) block

  19. Anaerobic degradation of a mixture of MtBE, EtBE, TBA, and benzene under different redox conditions.

    Science.gov (United States)

    van der Waals, Marcelle J; Pijls, Charles; Sinke, Anja J C; Langenhoff, Alette A M; Smidt, Hauke; Gerritse, Jan

    2018-04-01

    The increasing use of biobased fuels and fuel additives can potentially change the typical fuel-related contamination in soil and groundwater. Anaerobic biotransformation of the biofuel additive ethyl tert-butyl ether (EtBE), as well as of methyl tert-butyl ether (MtBE), benzene, and tert-butyl alcohol (TBA, a possible oxygenate metabolite), was studied at an industrially contaminated site and in the laboratory. Analysis of groundwater samples indicated that in the field MtBE was degraded, yielding TBA as major product. In batch microcosms, MtBE was degraded under different conditions: unamended control, with medium without added electron acceptors, or with ferrihydrite or sulfate (with or without medium) as electron acceptor, respectively. Degradation of EtBE was not observed under any of these conditions tested. TBA was partially depleted in parallel with MtBE. Results of microcosm experiments with MtBE substrate analogues, i.e., syringate, vanillate, or ferulate, were in line with the hypothesis that the observed TBA degradation is a cometabolic process. Microcosms with ferulate, syringate, isopropanol, or diethyl ether showed EtBE depletion up to 86.5% of the initial concentration after 83 days. Benzene was degraded in the unamended controls, with medium without added electron acceptors and with ferrihydrite, sulfate, or chlorate as electron acceptor, respectively. In the presence of nitrate, benzene was only degraded after addition of an anaerobic benzene-degrading community. Nitrate and chlorate hindered MtBE, EtBE, and TBA degradation.

  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. 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...

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

    Indian Academy of Sciences (India)

    TECS

    -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 ...

  3. 2-tert-Butyl-5,6,7,8,9,10-hexahydrocyclohepta[b]indole

    Directory of Open Access Journals (Sweden)

    Janina Wobbe

    2011-09-01

    Full Text Available 2-tert-Butyl-5,6,7,8,9,10-hexahydrocyclohepta[b]indole was synthesized by reaction of cycloheptanone and (4-tert-butylphenylhydrazine hydrochloride in the presence of sodium acetate and sulfuric acid in glacial acetic acid via Fischer indole synthesis.

  4. IRIS Toxicological Review of Tert-Butyl Alcohol (Tert-Butanol) (External Review Draft)

    Science.gov (United States)

    The IRIS Toxicological Review of tert-Butyl Alcohol (tert-Butanol) was released for external peer review in June 2017. EPA’s Science Advisory Board’s (SAB) Chemical Assessment Advisory Committee (CAAC) will conduct a peer review of the scientific basis supporting ...

  5. IRIS Toxicological Review of Tert-Butyl Alcohol (Tert-Butanol) (Public Comment Draft)

    Science.gov (United States)

    EPA is developing an Integrated Risk Information System (IRIS) assessment of tert-butyl Alcohol (tert-butanol) and has released the public comment draft assessment for public comment and external peer review. When final, the assessment will appear on the IRIS databa...

  6. Azobenzene versus 3,3',5,5'-tetra-tert-butyl-azobenzene (TBA) at Au(111): characterizing the role of spacer groups.

    Science.gov (United States)

    McNellis, Erik R; Bronner, Christopher; Meyer, Jörg; Weinelt, Martin; Tegeder, Petra; Reuter, Karsten

    2010-06-28

    We present large-scale density-functional theory (DFT) calculations and temperature programmed desorption measurements to characterize the structural, energetic and vibrational properties of the functionalized molecular switch 3,3',5,5'-tetra-tert-butyl-azobenzene (TBA) adsorbed at Au(111). Particular emphasis is placed on exploring the accuracy of the semi-empirical dispersion correction approach to semi-local DFT (DFT-D) in accounting for the substantial van der Waals component in the surface bonding. In line with previous findings for benzene and pure azobenzene at coinage metal surfaces, DFT-D significantly overbinds the molecule, but seems to yield an accurate adsorption geometry as far as can be judged from the experimental data. Comparing the trans adsorption geometry of TBA and azobenzene at Au(111) reveals a remarkable insensitivity of the structural and vibrational properties of the -N[double bond, length as m-dash]N- moiety. This questions the established view of the role of the bulky tert-butyl-spacer groups for the switching of TBA in terms of a mere geometric decoupling of the photochemically active diazo-bridge from the gold substrate.

  7. Aerobic biodegradation of tert-butyl alcohol (TBA) by psychro- and thermo-tolerant cultures derived from granular activated carbon (GAC).

    Science.gov (United States)

    Reinauer, Kimberly M; Zhang, Yang; Yang, Xiaomin; Finneran, Kevin T

    2008-04-01

    Tert-butyl alcohol (TBA) is a metabolite of methyl tert-butyl ether and is itself possibly a fuel oxygenate. The goals of this study were to enrich and characterize TBA-degrading micro-organism(s) from a granular activated carbon (GAC) unit currently treating TBA. The results reported herein describe the first aerobic, TBA-degrading cultures derived from GAC. Strains KR1 and YZ1 were enriched from a GAC sample in a bicarbonate-buffered freshwater medium. TBA was degraded to 10% of the initial concentration (2-5 mM) within 5 days after initial inoculation and was continuously degraded within 1 day of each re-amendment. Resting cell suspensions mineralized 70 and 60% of the TBA within 24 h for KR1 and YZ1, respectively. Performance optimization with resting cells was conducted to investigate kinetics and the extent of TBA degradation as influenced by oxygen, pH and temperature. The most favorable temperature was 37 degrees C; however, TBA was degraded from 4 to 60 degrees C, indicating that the culture will sufficiently treat groundwater without heating. This is also the first report of psychrotolerant or thermotolerant TBA biodegradation. The pH range for TBA degradation ran from 5.0 to 9.0. Phylogenetic data using a partial 16S rRNA gene sequence (570 bases) suggest that the primary members of KR1 and YZ1 include uncharacterized organisms within the genera Hydrogenophaga, Caulobacter, and Pannonibacter.

  8. tert-Butyl 2-methyl-2-(4-nitrobenzoylpropanoate

    Directory of Open Access Journals (Sweden)

    Chelsey M. Crosse

    2010-02-01

    Full Text Available The title compound, C15H19NO5, is bent with a dihedral angle of 61.8 (2° between the mean planes of the benzene ring and a group encompassing the ester functionality (O=C—O—C. The dihedral angle of 0.8 (2° between the mean planes of the nitro group and the benzene ring indicates near coplanarity. In the crystal, each molecule is linked to four adjacent molecules by weak C—H...O hydrogen-bonding interactions. Both benzene H atoms ortho to the ketone O atom form C—H...O hydrogen bonds with the keto O atoms of two neighboring molecules (of the keto and ester groups, respectively, and the two other interactions involve the H atoms from a methyl group of the dimethyl residue, displaying C—H...O interactions with the O atoms of the nitro groups. These four interactions for each molecule lead to the formation of two-dimensional sheets with a hydrophilic interior, held together by weak hydrogen-bonded interactions, and a hydrophobic exterior composed of protruding methyl groups which interstack with the methyl groups in adjacent sheets.

  9. 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.

  10. {2,6-Bis[(di-tert-butyl-phosphino)-methyl]-phenyl}chloridonickel(II).

    Science.gov (United States)

    Boro, Brian J; Dickie, Diane A; Goldberg, Karen I; Kemp, Richard A

    2008-09-20

    In the title compound, [Ni(C(24)H(43)P(2))Cl], the Ni atom adopts a distorted square-planar geometry, with the P atoms of the 2,6-bis-[(di-tert-butyl-phosphino)meth-yl]phenyl ligand trans to one another. The P-Ni-P plane is twisted out of the plane of the aromatic ring by 21.97 (6)°.

  11. 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.

  12. Carbonyl{3,3′-di-tert-butyl-5,5′-dimethoxy-2,2′-bis[(4,4,5,5-tetramethyl-1,3,2-dioxaphospholan-2-yloxy]biphenyl-κ2P,P′}hydrido(triphenylphosphane-κPrhodium(I diethyl ether trisolvate

    Directory of Open Access Journals (Sweden)

    Detlef Selent

    2013-01-01

    Full Text Available In the title compound, [RhH(C74H68O8P2(C18H15P(CO]·3C4H10O, the CHP3 coordination set at the RhI ion is arranged in a distorted trigonal–bipyramidal geometry with the P atoms adopting equatorial coordination sites and the C atom of the carbonyl ligand as well as the H atom adopting the axial sites. The asymmetric unit contains two very similar molecules of the rhodium complex, two half-occupied diethyl ether molecules and further diethyl ether solvent molecules which could not be modelled successfully. Therefore contributions of the latter were removed from the diffraction data using the SQUEEZE procedure in PLATON [Spek (2009. Acta Cryst. D65, 148–155].

  13. (N-Benzyl-N-ethyl­dithio­carbamato)di-tert-butyl­chloridotin(IV)

    OpenAIRE

    Abdul Muthalib, Amirah Faizah; Baba, Ibrahim; Mohamed Tahir, Mohamed Ibrahim; Tiekink, Edward R. T.

    2011-01-01

    The SnIV atom in the title diorganotin dithio­carbamate, [Sn(C4H9)2Cl(C10H12NS2)], is penta­coordinated by an asymmetrically coordinating dithio­carbamate ligand, a Cl and two C atoms of the Sn-bound tert-butyl groups. The resulting C2ClS2 donor set defines a coordination geometry inter­mediate between square pyramidal and trigonal bipyramidal with a slight tendency towards the former. In the crystal structure, C—H⋯π contacts link centrosymmetrically related mol­ecules into dimeric aggregates...

  14. Di-tert-butyl­chlorido(N,N-dibenzyl­dithio­carbamato)tin(IV)

    Science.gov (United States)

    Abdul Muthalib, Amirah Faizah; Baba, Ibrahim; Mohamed Tahir, Mohamed Ibrahim; Tiekink, Edward R. T.

    2011-01-01

    The SnIV atom in the title diorganotin dithio­carbamate, [Sn(C4H9)2(C15H14NS2)Cl], is penta­coordinated by an asymmetrically coordinating dithio­carbamate ligand, a Cl atom and two C atoms of the Sn-bound tert-butyl groups. The resulting C2ClS2 donor set defines a coordination geometry inter­mediate between square pyramidal and trigonal bipyramidal with a slight tendency towards the former. PMID:21522304

  15. Di-tert-butyl-chlorido(N,N-dibenzyl-dithio-carbamato)tin(IV).

    Science.gov (United States)

    Abdul Muthalib, Amirah Faizah; Baba, Ibrahim; Mohamed Tahir, Mohamed Ibrahim; Tiekink, Edward R T

    2011-02-26

    The Sn(IV) atom in the title diorganotin dithio-carbamate, [Sn(C(4)H(9))(2)(C(15)H(14)NS(2))Cl], is penta-coordinated by an asymmetrically coordinating dithio-carbamate ligand, a Cl atom and two C atoms of the Sn-bound tert-butyl groups. The resulting C(2)ClS(2) donor set defines a coordination geometry inter-mediate between square pyramidal and trigonal bipyramidal with a slight tendency towards the former.

  16. (N-Benzyl-N-ethyl­dithio­carbamato)di-tert-butyl­chloridotin(IV)

    Science.gov (United States)

    Abdul Muthalib, Amirah Faizah; Baba, Ibrahim; Mohamed Tahir, Mohamed Ibrahim; Tiekink, Edward R. T.

    2011-01-01

    The SnIV atom in the title diorganotin dithio­carbamate, [Sn(C4H9)2Cl(C10H12NS2)], is penta­coordinated by an asymmetrically coordinating dithio­carbamate ligand, a Cl and two C atoms of the Sn-bound tert-butyl groups. The resulting C2ClS2 donor set defines a coordination geometry inter­mediate between square pyramidal and trigonal bipyramidal with a slight tendency towards the former. In the crystal structure, C—H⋯π contacts link centrosymmetrically related mol­ecules into dimeric aggregates. PMID:21522295

  17. (N-Benzyl-N-ethyl-dithio-carbamato)di-tert-butyl-chloridotin(IV).

    Science.gov (United States)

    Abdul Muthalib, Amirah Faizah; Baba, Ibrahim; Mohamed Tahir, Mohamed Ibrahim; Tiekink, Edward R T

    2011-02-26

    The Sn(IV) atom in the title diorganotin dithio-carbamate, [Sn(C(4)H(9))(2)Cl(C(10)H(12)NS(2))], is penta-coordinated by an asymmetrically coordinating dithio-carbamate ligand, a Cl and two C atoms of the Sn-bound tert-butyl groups. The resulting C(2)ClS(2) donor set defines a coordination geometry inter-mediate between square pyramidal and trigonal bipyramidal with a slight tendency towards the former. In the crystal structure, C-H⋯π contacts link centrosymmetrically related mol-ecules into dimeric aggregates.

  18. Review of quantitative surveys of the length and stability of MTBE, TBA, and benzene plumes in groundwater at UST sites.

    Science.gov (United States)

    Connor, John A; Kamath, Roopa; Walker, Kenneth L; McHugh, Thomas E

    2015-01-01

    Quantitative information regarding the length and stability condition of groundwater plumes of benzene, methyl tert-butyl ether (MTBE), and tert-butyl alcohol (TBA) has been compiled from thousands of underground storage tank (UST) sites in the United States where gasoline fuel releases have occurred. This paper presents a review and summary of 13 published scientific surveys, of which 10 address benzene and/or MTBE plumes only, and 3 address benzene, MTBE, and TBA plumes. These data show the observed lengths of benzene and MTBE plumes to be relatively consistent among various regions and hydrogeologic settings, with median lengths at a delineation limit of 10 µg/L falling into relatively narrow ranges from 101 to 185 feet for benzene and 110 to 178 feet for MTBE. The observed statistical distributions of MTBE and benzene plumes show the two plume types to be of comparable lengths, with 90th percentile MTBE plume lengths moderately exceeding benzene plume lengths by 16% at a 10-µg/L delineation limit (400 feet vs. 345 feet) and 25% at a 5-µg/L delineation limit (530 feet vs. 425 feet). Stability analyses for benzene and MTBE plumes found 94 and 93% of these plumes, respectively, to be in a nonexpanding condition, and over 91% of individual monitoring wells to exhibit nonincreasing concentration trends. Three published studies addressing TBA found TBA plumes to be of comparable length to MTBE and benzene plumes, with 86% of wells in one study showing nonincreasing concentration trends. © 2014 GSI Environmental Inc. Groundwater published by Wiley Periodicals, Inc. on behalf of National Ground Water Association.

  19. Reactive Imprint Lithography: Combined Topographical Patterning and Chemical Surface Functionalization of Polystyrene-block-poly(tert-butyl acrylate) Films

    NARCIS (Netherlands)

    Duvigneau, Joost; Cornelissen, Stijn; Bardajı´Valls, Nuria; Schönherr, Holger; Vancso, Gyula J.

    2009-01-01

    Here, reactive imprint lithography (RIL) is introduced as a new, one-step lithographic tool for the fabrication of large-area topographically patterned, chemically activated polymer platforms. Films of polystyrene-block-poly(tert-butyl acrylate) (PS-b-PtBA) are imprinted with PDMS master stamps at

  20. Voltammetric Determination of Nitro Derivative of Synthetic Antioxidant 2,6-di-tert-butyl-4-methyl-phenol

    Czech Academy of Sciences Publication Activity Database

    Chýlková, J.; Machalický, O.; Tomášková, M.; Šelešovská, R.; Navrátil, Tomáš

    2016-01-01

    Roč. 49, č. 1 (2016), s. 92-106 ISSN 0003-2719 R&D Projects: GA ČR(CZ) GAP208/12/1645 Institutional support: RVO:61388955 Keywords : 2,6-di-tert-butyl-4-methyl-phenol * handing drop mercury electrode * nitration Subject RIV: CG - Electrochemistry Impact factor: 1.150, year: 2016

  1. Substituted 2,2'-bipyridines by nickel-catalysis: 4,4'-di-tert-butyl-2,2'-bipyridine.

    Science.gov (United States)

    Buonomo, Joseph A; Everson, Daniel A; Weix, Daniel J

    2013-11-01

    A simple, ligand-free synthesis of the important bipyridyl ligand 4,4'-di- tert -butyl-2,2'-bipyridine is presented. 5,5'-bis(trifluoromethyl)-2,2'-bipyridine is also synthesized by the same protocol. The syntheses efficiently couple the parent 2-chlorpyridies by a nickel-catalyzed dimerization with manganese powder as the terminal reductant.

  2. Novel process window for the safe and continuous synthesis of tert.-butyl peroxy pivalate in a micro reactor

    NARCIS (Netherlands)

    Illg, T.; Hessel, V.; Löb, P.; Schouten, J.C.

    2011-01-01

    In this paper, the two step synthesis of tert.-butyl peroxy pivalate using two different flow regimes is introduced, in particular the use of "segmented flow" and the concept of "dispersed flow". The use of the segmented flow process, in this case, is challenging due to the very low interfacial

  3. 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.

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

    International Nuclear Information System (INIS)

    Alia, Mario; Ramos, Sonia; Mateos, Raquel; Granado-Serrano, Ana Belen; Bravo, Laura; Goya, Luis

    2006-01-01

    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 μM quercetin completely prevented lactate dehydrogenase leakage from the cells. Pretreatment for 2 or 20 h with all doses of quercetin (0.1-10 μM) 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 μM and for 20 h with 5 μM 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

  5. Photoelectric conversion and electrochromic properties of lutetium tetrakis(tert-butyl)bisphthalocyaninate

    International Nuclear Information System (INIS)

    Hu, Andrew Teh; Hu Tenyi; Liu Lungchang

    2003-01-01

    Both photoelectric and electrochromic effects on lutetium tetrakis(tert-butyl)bisphthalocyaninate (Lu(TBPc) 2 ) have been carried out in this study. Lu(TBPc) 2 is known for its electrochromic performance, but its photoelectric effect has not mentioned in the literature. The electrochromic properties of Lu(TBPc) 2 have been measured by cyclic voltammetry (CV) and UV-Vis spectrometer at the same time. It takes less than 1.5 s for the color to change from red to green under 0.9 V. Its cycle life is at least over 500 times. Furthermore, we also investigate its photoelectric conversion properties. Its photoelectric cell exhibits a positive photo-electricity conversion effect with a short-circuit photocurrent (46.4 μA/cm 2 ) under illumination of white light (1.201 mW/cm 2 )

  6. Influence of mass transport towards deactivation in tert-butyl-source driven isobutane/2-butene alkylation

    Energy Technology Data Exchange (ETDEWEB)

    Aschauer, S.J.; Jess, A. [Bayreuth Univ. (Germany). Dept. of Chemical Engineering

    2011-07-01

    The deactivation of i-butane/trans-2-butene alkylation using tert-butyl-halide promoted ionic liquid catalysts is studied.Here, the mass transport was modified by varying the feed rate and the type of promoter addition. The experimental data show that the deactivation increases with increasing feed rate. Moreover, a biliquid foam is formed when feed rates above 1 g/min are adjusted. As the results indicate a strong influence of the biliquid foam and its formation on deactivation, both aspects are also discussed.When the promoter is added to the feed mixture an increase of conversion with time on stream is observed. A deactivation in continuous promoter addition mode could not be noted in the investigated time-on-stream range. (orig.)

  7. N-tert-Butyl-3-hydroxy-5-androstene-17-carboxamide monohydrate

    Directory of Open Access Journals (Sweden)

    Jiang-Sheng Li

    2009-07-01

    Full Text Available In the title compound, C24H39NO2·H2O, the A and C rings of the pregnolene derivative sterol adopt chair conformations, with the B ring in a flattened chair conformation and the five-membered ring in an envelope conformation twisted about the C/D ring junction. The N-tert-butylcarboxamide substituent is equatorial. The 3β-hydroxy H atom and one H atom of the water molecule are disordered over two positions with equal occupancies. In the crystal structure, O—H...O hydrogen bonds between the 3β-hydroxy groups of neighbouring molecules form dimers in the bc plane and these dimers are stacked along the a axis by additional O—H...O hydrogen bonds involving the water molecules. The steric effect of the bulky tert-butyl substituent in the carboxamide chain precludes hydrogen-bond formation by the N—H group.

  8. Effect of Methyl tert-Butyl Ether in Standard Tests for Mutagenicity and Environmental Toxicity

    Czech Academy of Sciences Publication Activity Database

    Vosáhlíková, M.; Cajthaml, Tomáš; Demnerová, K.; Pazlarová, Jarmila

    2006-01-01

    Roč. 21, č. 6 (2006), s. 599-605 ISSN 1520-4081 Institutional research plan: CEZ:AV0Z50200510 Keywords : toxicity * mtbe * ames test Subject RIV: EE - Microbiology, Virology Impact factor: 1.582, year: 2006

  9. Update on dissolution of gallstones with methyl-tert-butyl ether

    International Nuclear Information System (INIS)

    van Sonnenberg, E.; D'Agostino, H.B.; Hofmann, A.F.; Casola, G.; Varney, R.R.; Jinich, H.; Steingart, C.; McQuade, K.; Hoyt, D.

    1989-01-01

    The authors have studied 50 patients who underwent percutaneous MTBE dissolution of gallstones with or without supplemental basketing. All patients had symptomatic gallbladder or ductal stones. Five patients underwent emergency gallbladder drainage for acute calculous cholecystitis; after recovery, their gallstones were dissolved or removed. The other 45 patients had elective gallstone dissolution; preliminary studies on these patients included plain film, US, oral cholecystography, and CT. Follow-up studies were chromatography, US, and cholecystography. Three patients underwent cholecystectomy after MTBE treatment; no averse effects of MTBE were seen histologically. Three patients had stone recurrence. The majority of patients were placed on ursodeoxycholic acid after stone dissolution

  10. 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...

  11. Actinide-carbon bonds: insertion reactions of carbon monoxide, tert-butyl isocyanide, and tert-butyl cyanide into [(Me3Si)2N]2MCH2Si(Me)2NSiMe3

    International Nuclear Information System (INIS)

    Simpson, S.J.; Andersen, R.A.

    1981-01-01

    The thorium or uranium metallacycles [(Me 2 Si) 2 N] 2 MCH 2 Si(Me) 2 NSiMe 3 (I) react with tert-butyl cyanide to give the six-membered ring compounds [(Me 3 Si) 2 N] 2 MN = C(t-Bu)CH 2 Si(Me) 2 NSiMe 3 . The metallacycles (I) also react with the isoelectronic molecules tert-butyl isocyanide and carbon monoxide to give the unique five-membered ring compounds with exocyclic carbon-carbon double bonds, [(Me 3 Si) 2 N] 2 MXC(=CH 2 )Si(Me) 2 NSiMe 3 , where X is t-BuN or oxygen. The four-membered ring metallacycles (I) give simple coordination complexes of the type [(Me 3 Si) 2 N] 2 MCH 2 Si-(Me) 2 NSiMe 3 (N 3 SiMe 3 ) with trimethylsilyl azide

  12. Standard thermochemical characteristics of combustion and formation of 3,5-di-tert-butyl-o-benzoquinone and 3,6-di-tert-butyl-o-benzoquinone at T = 298.15 K

    International Nuclear Information System (INIS)

    Pashanova, Kira I.; Abakumov, Gleb A.; Markin, Alexey V.; Piskunov, Alexander V.; Smirnova, Natalia N.

    2016-01-01

    Highlights: • We report the results of thermochemical study for benzoquinone derivatives. • Optimal conditions for determination of combustion energy for benzoquinone were done. • The formation enthalpies for crystalline benzoquinone have been detected at T = 298.15 K. • The formation enthalpy of isomeric quinones were compared. - Abstract: Optimal conditions for investigations of thermodynamic properties have been determined experimentally by the method of combustion calorimetry for compounds of the o-benzoquinone series. In the present work, the energies of combustion in oxygen were measured at T = 298.15 K by static bomb combustion calorimetry for 3,5-di-tert-butyl-o-benzoquinone and 3,6-di-tert-butyl-o-benzoquinone. The experimental values have been used to calculate the standard (p° = 0.1 MPa) molar enthalpy of combustion Δ_cH"o_m and formation Δ_fH"o_m for the examined compounds in the crystalline phase.

  13. Effect of tert-Butyl Functionalization on the Photoexcited Decay of a Fe(II)-N-Heterocyclic Carbene Complex

    DEFF Research Database (Denmark)

    Pápai, Mátyás Imre; Penfold, Thomas J.; Møller, Klaus Braagaard

    2016-01-01

    -vibronic quantum dynamics simulations on the Fe-N-heterocyclic carbene complex, [Fe(btbip)2]2+ (btbip = 2,6-bis(3-tert-butyl-imidazole-1-ylidene)pyridine). The results demonstrate that a relatively minor structural change compared to its parent complex, [Fe(bmip)2]2+ (bmip = 2,6-bis(3-methyl-imidazole-1-ylidene....... This occurs because the tert-butyl functionalization stabilizes the 1MC states, enabling the 1,3MLCT → 1MC population transfer to occur close to the Franck-Condon geometry, making the conversion very efficient. Subsequently, a spin cascade occurs within the MC manifold, leading to the population of triplet...

  14. Preparation of Langmuir–Blodgett thin films of calix[6]arenes and p-tert butyl group effect on their gas sensing properties

    Energy Technology Data Exchange (ETDEWEB)

    Ozmen, Mustafa, E-mail: musozmen@gmail.com [Department of Chemistry, University of Selcuk, 42075 Konya (Turkey); Ozbek, Zikriye, E-mail: zikriye@comu.edu.tr [Department of Bioengineering, University of Canakkale Onsekiz Mart, 17100 Canakkale (Turkey); Bayrakci, Mevlut [Department of Bioengineering, University of Karamanoglu Mehmetbey, 70200 Karaman (Turkey); Ertul, Seref; Ersoz, Mustafa [Department of Chemistry, University of Selcuk, 42075 Konya (Turkey); Capan, Rifat [Department of Physics, University of Balikesir, 10145 Balikesir (Turkey)

    2015-12-30

    Graphical abstract: - Highlights: • In this work, we prepared Langmuir–Blodgett films of calix[6]arene derivatives. • Then LB films of calixarene compounds were characterized. • Organic vapor sensing properties of prepared LB films were investigated. - Abstract: Organic vapor sensing properties of Langmuir–Blodgett (LB) thin films of p-tert-butyl calix[6]arene and calix[6]arene, and their certain characterization are reported in this work. LB films of these calixarenes have been characterized by contact angle measurement, quartz crystal microbalance (QCM), scanning electron microscopy (SEM) and atomic force microscopy (AFM). QCM system was used for the measurement of sensor response against chloroform, benzene, toluene and ethanol vapors. Forming of stable monolayers was observed at the water surface using surface pressure–area isotherm graph. The results indicate that good quality, uniform LB films can be prepared with a transfer ratio of over 0.95. Due to the adsorption of vapors into the LB film structures; they yield a response to all vapors as of large, fast, and reproducible.

  15. Entanglement Dynamics in Miscible Polyisoprene / Poly(p-tert-butyl styrene) Blends

    Science.gov (United States)

    Watanabe, Hiroshi

    2011-03-01

    Viscoelastic and dielectric behavior was examined for well entangled, miscible blends of high- M cis-polyisoprene (PI) and poly(p-tert-butyl styrene) (PtBS). The dielectric data of the blends, reflecting the global motion of the PI chains having the type-A dipoles, indicated that PI and PtBS were the fast and slow components therein. At high temperatures T , the blends exhibited two-step entanglement plateau. The high frequency (ω) plateau height was well described by a simple mixing rule of the entanglement length based on the number fraction of the Kuhn segments. At low T , the blend exhibited the Rouse-like power-law behavior of storage and loss moduli, G ' = G ~ω0.5 , in the range of ω where the high- ω plateau was supposed to emerge. This lack of the high- ω plateau was attributed to retardation of the Rouse equilibration of the PI chain over the entanglement length due to the hindrance from the slow PtBS chains: The PI and PtBS chains were equilibrated cooperatively, and the retardation due to PtBS shortened the plateau for PI to a width not resolved experimentally. A simple model for this cooperative equilibration formulated on the basis of the dielectric data described the viscoelastic data surprisingly well.

  16. Facile reactions of gold(i) complexes with tri(tert-butyl)azadiboriridine.

    Science.gov (United States)

    Shang, Rong; Saito, Souta; Jimenez-Halla, J Oscar C; Yamamoto, Yohsuke

    2018-04-17

    Direct structural evidence for group 11 metal-mediated B-B bond activation was obtained from reactions of tri(tert-butyl)azadiboriridine (1) with AuCl(L) complexes. The AuCl(SMe2) reaction afforded [η2-B,B-B(tBu)N(tBu)B(tBu)]AuCl (2) by ligand displacement. More donating phosphines as co-ligands led to B-B bond cleavage accompanied by either halide or L migration to form boron-gold complexes 3 (L = PPh3) and 4 (L = PMe3). A similar product 5, which is isostructural to 4, was obtained by the addition of dimethylaminopyridine (DMAP) to 2-4. Complexes 2-5 constitute rare examples of metal complexes bearing two Lewis acidic centres. The effect of the boryl ligand was demonstrated in the formation of a gold(i) complex 6 bearing a 5-membered heterocycle from 3 and tert-butylisonitrile. Plausible reaction mechanisms that led to these complexes and their bonding situation were explored computationally at the DFT level.

  17. Protective effects of hesperidin against oxidative stress of tert-butyl hydroperoxide in human hepatocytes.

    Science.gov (United States)

    Chen, Mingcang; Gu, Honggang; Ye, Yiyi; Lin, Bing; Sun, Lijuan; Deng, Weiping; Zhang, Jingzhe; Liu, Jianwen

    2010-10-01

    Increasing evidence regarding free radical generating agents and the inflammatory process suggest that accumulation of reactive oxygen species (ROS) could involve hepatotoxicity. Hesperidin, a naturally occurring flavonoid presents in fruits and vegetables, has been reported to exert a wide range of pharmacological effects that include antioxidant, anti-inflammatory, antihypercholesterolemic, and anticarcinogenic actions. However, the cytoprotection and mechanism of hesperidin to neutralize oxidative stress in human hepatic L02 cells remain unclear. In this work, we assessed the capability of hesperidin to prevent tert-butyl hydroperoxide (t-BuOOH)-induced cell damage by augmenting cellular antioxidant defense. Hesperidin significantly protected hepatocytes against t-BuOOH-induced cell cytotoxicity, such as mitochondrial membrane potential (MMP) deplete and lactate dehydrogenase (LDH) release. Hesperidin also remarkably prevented indicators of oxidative stress, such as the ROS and lipid peroxidation level in a dose-dependent manner. Western blot showed that hesperidin facilitated ERK/MAPK phosphorylation which appeared to be responsible for nuclear translocation of Nrf2, thereby inducing cytoprotective heme oxygenase-1 (HO-1) expression. Based on the results described above, it suggested that hesperidin has potential as a therapeutic agent in the treatment of oxidative stress-related hepatocytes injury and liver dysfunctions. Copyright © 2010 Elsevier Ltd. All rights reserved.

  18. Two DSC Glass Transitions in Miscible Blends of Polyisoprene / Poly(4-tert-butyl styrene)

    Science.gov (United States)

    Zhao, Junshu; Sun, Ye; Yu, Lian; Ediger, Mark

    2009-03-01

    Conventional and temperature modulated differential scanning calorimetry experiments have been carried out on miscible blends of polyisoprene (PI) and poly(4-tert-butyl styrene) (P4tBS) over a broad composition range. This system is characterized by an extraordinarily large component Tg difference (˜215 K) between the two homopolymers. Two distinct calorimetric Tgs were observed in blends with an intermediate composition range (25%˜50% PI) by both conventional and temperature modulated DSC. Good agreement was found between the Tg values measured by the two methods. Fitting of the measured Tgs to the Lodge-McLeish model gives a φself of 0.62˜0.64 for PI in this blend and 0.02˜0.05 for P4tBS. The extracted φself for PIis comparable to reported values for PEO in blends with PMMA and is significantly larger than those reported for other PI blends with smaller component Tg differences. This observation suggests the presence of a confinement effect in PI/P4tBS blends, which results in enhanced fast component dynamics below the effective Tg of the slow component.

  19. Redox Regulation of the Tumor Suppressor PTEN by Hydrogen Peroxide and Tert-Butyl Hydroperoxide

    Directory of Open Access Journals (Sweden)

    Ying Zhang

    2017-05-01

    Full Text Available Organic peroxides and hydroperoxides are skin tumor promoters. Free radical derivatives from these compounds are presumed to be the prominent mediators of tumor promotion. However, the molecular targets of these species are unknown. Phosphatase and tensin homologs deleted on chromosome 10 (PTEN are tumor suppressors that play important roles in cell growth, proliferation, and cell survival by negative regulation of phosphoinositol-3-kinase/protein kinase B signaling. PTEN is reversibly oxidized in various cells by exogenous and endogenous hydrogen peroxide. Oxidized PTEN is converted back to the reduced form by cellular reducing agents, predominantly by the thioredoxin (Trx system. Here, the role of tert-butyl hydroperoxide (t-BHP in redox regulation of PTEN was analyzed by using cell-based and in vitro assays. Exposure to t-BHP led to oxidation of recombinant PTEN. In contrast to H2O2, PTEN oxidation by t-BHP was irreversible in HeLa cells. However, oxidized PTEN was reduced by exogenous Trx system. Taken together, these results indicate that t-BHP induces PTEN oxidation and inhibits Trx system, which results in irreversible PTEN oxidation in HeLa cells. Collectively, these results suggest a novel mechanism of t-BHP in the promotion of tumorigenesis.

  20. Solvent extraction of technetium from alkaline waste media using bis-4,4'(5')[(tert-butyl)cyclohexano]-18-crown-6

    International Nuclear Information System (INIS)

    Bonnesen, P.V.; Presley, D.J.; Moyer, B.A.

    1995-01-01

    The crown ether bis-4,4'(5')[(tert-butyl)cyclohexano]-18-crown-6 can be utilized in a solvent-extraction process for the removal of technetium as pertechnetate ion, TcO 4 - from solutions simulating highly radioactive alkaline defense wastes (''tank wastes'') stored at several sites in the United States. The process employs non-halogenated and non-volatile diluents and modifiers and includes an efficient stripping procedure using only water. More than 95% of the pertechnetate present at 6 x 10 -5 M in Melton Valley (Oak Ridge, TN) and Hanford (Washington) tank-waste simulants was removed following two cross-current extraction contacts using 0.02 M bis-4,4'(5')[(tertbutyl)cyclohexano]- 18-crown-6 in 2:1 vol/vol TBP/Isopar reg-sign M diluent at 25 C. Similarly, for both simulants, more than 98% of the pertechnetate contained in the solvent was back-extracted following two cross-current stripping contacts using deionized water

  1. Dynamics in miscible blends of polyisoprene and poly(p-tert-butyl styrene): thermo–rheological behavior of components

    OpenAIRE

    Chen, Quan; Matsumiya, Yumi; Watanabe, Hiroshi

    2011-01-01

    For miscible blends of moderately entangled cis-polyisoprene (PI) and poly(p-tert-butyl styrene) (PtBS), viscoelastic and dielectric properties were examined over a wide range of temperature (T) to discuss the thermo–rheological behavior of respective components. Because PI has the type-A dipole, whereas PtBS does not, the slow dielectric response of the blends was exclusively attributed to the global motion of the PI chains therein. In most of the blends examined, the viscoelastic relaxation...

  2. Novel synthesis of methoxymethyl benzene by electrochemical coupling reaction of toluene with methanol in ionic liquid media.

    Science.gov (United States)

    Chen, Fengtao; Wang, Bo; Ma, Hongzhu

    2009-06-15

    An ionic liquid (1-butyl-3-methylimidazolium dibutyl phosphate) was prepared and characterized by cyclic voltammogram (CV) and Fourier transform infrared spectrometer (FT-IR). The ionic liquid exhibited good catalytic activity for the electrochemical reaction of toluene with methanol assisted with a pair of porous graphite plane electrodes and product yield higher than 56% was observed. In addition, the electrochemical process was detected by UV-vis spectrum and the products were analyzed by gas chromatography/mass spectrometry (GC/MS). According to the experimental results, a possible free radical reaction mechanism was proposed. It may be concluded that a simply and feasible electrochemical coupling reaction at room temperature and atmospheric pressure may be possible. Compared with methyl tert-butyl ether (MTBE), the main product (methoxymethyl benzene) used as booster to improve fuel combustion was also studied.

  3. 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.

  4. Formation of Germa-ketenimine on the Ge(100) Surface by Adsorption of tert-Butyl Isocyanide.

    Science.gov (United States)

    Shong, Bonggeun; Yoo, Jong Suk; Sandoval, Tania E; Bent, Stacey F

    2017-06-28

    Reactions of the (100) surfaces of Ge and Si with organic molecules have been generally understood within the concept of "dimers" formed by the 2 × 1 surface reconstruction. In this work, the adsorption of tert-butyl isocyanide on the Ge(100)-2 × 1 surface at large exposures is investigated under ultrahigh vacuum conditions. A combination of infrared spectroscopy, X-ray photoelectron spectroscopy, and temperature-programmed desorption experiments along with dispersion-corrected density functional theory calculations is used to determine the surface products. Upon adsorption of a dense monolayer of tert-butyl isocyanide, a product whose structure resembles a germa-ketenimine (N=C=Ge) with σ donation toward and π back-donation from the Ge(100) surface appears. Formation of this structure involves divalent-type surface Ge atoms that arise from cleavage of the Ge(100)-2 × 1 surface dimers. Our results reveal an unprecedented class of reactions of organic molecules at the Ge(100) surface.

  5. Tailored Interfaces for Biosensors and Cell-Surface Interaction Studies via Activation and Derivatization of Polystyrene-block-poly(tert-butyl acrylate) Thin Films

    NARCIS (Netherlands)

    Feng, C.L.; Embrechts, A.; Bredebusch, Ilona; Bouma, Anita; Schnekenburger, Jürgen; Garcia Parajo, M.F.; Domschke, Wolfram; Vancso, Gyula J.; Schönherr, Holger

    2007-01-01

    Thin spin-coated films of polystyrene-block-poly(tert-butyl acrylate) (PS690-b-PtBA1210) on various substrates are introduced as versatile, robust reactive platform for the immobilization of (bio)molecules for the fabrication of tailored biointerfaces. The films are characterized by high stability

  6. Hydrophobic hydration and anomalous excess partial molar volume of tert-butyl alcohol-water mixture studied by quasielastic neutron scattering

    International Nuclear Information System (INIS)

    Nakada, Masaru; Maruyama, Kenji; Misawa, Masakatsu; Yamamuro, Osamu

    2007-01-01

    Quasielastic neutron scattering has been used to investigate the hydration of alcohol clusters in tert-butyl alcohol-water mixture. The measurements were made in a range of alcohol concentration, x TBA , from 0.0 to 0.17 in mole fraction at 25degC. Fraction, α, of water molecules hydrated to fractal-surface of alcohol clusters in tert-butyl alcohol-water mixture was obtained as a function of alcohol concentration. Average hydration number N WS of tert-butyl alcohol molecule was derived from the value of α as a function of alcohol concentration. The value of N WS for an isolated alcohol molecule in water was 19-21. The anomalous excess partial molar volume of tert-butyl alcohol-water mixture was interpreted successfully by applying the same model with the same values of volume parameter as used for 1-propanol-water mixture, δ 1 (=-0.36 cm 3 ·mol -1 ) and δ 2 (=0.60 cm 3 ·mol -1 ). (author)

  7. Bromine catalyzed conversion of S-tert-butyl groups into versatile and, for self-assembly processes accessible, acetyl-protected thiols.

    Science.gov (United States)

    Blaszczyk, Alfred; Elbing, Mark; Mayor, Marcel

    2004-10-07

    The facile and efficient conversion of a tert-butyl protecting group to an acetyl protecting group for thiols by catalytic amounts of bromine in acetyl chloride and the presence of acetic acid has been developed. The fairly mild reaction conditions are of particular interest for new protecting group strategies for sulfur functionalised target structures. Copyright 2004 The Royal Society of Chemistry

  8. (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.

  9. Calculation of carbon-14, chlorine-37, and deuterium kinetic isotope effects in the solvolysis of tert-butyl chloride

    International Nuclear Information System (INIS)

    Burton, G.W.; Sims, L.B.; Wilson, J.C.; Fry, A.

    1977-01-01

    In the solvolysis of tert-butyl chloride, satisfactory α-carbon-14, β-deuterium, and chlorine kinetic isotope effects (KIE) may be calculated for a productlike transition state characterized by bond orders n/sub C Cl/ = 0.2, n/sub C C/ = 1.18, and n/sub C H/ = 0.94, employing a diagonal valence force field, provided that allowance is made for hydrogen-bonded solvation of the developing chloride ion with n/sub Cl H/ approx. 0.05 (approx. 7 kcal/mole hydrogen bonds). The effect of the three solvating molecules appears to be to increase the ''effective'' mass of the incipient chloride ion and to decrease the loss of zero-point energy in going to the transition state. Reaction coordinates more complicated than a simple heterolysis of the carbon-chlorine bond appear to be unnecessary and there is no advantage in employing force fields more complex than a simple valence force field containing only diagonal elements for both the reactant and the transition state model. The structural and bonding features of the proposed transition state are in accord with earlier more qualitative conclusions concerning the polar nature and productlike character of the transition state, and provide a reasonable explanation of the kinetic and equilibrium isotope effects (EIE) for the reaction. An alternative transition state model involving weak solvent nucleophilic assistance provides reasonable calculated values for the KIE, but the EIE strongly suggest the importance of solvation of the leaving group which, together with the hyperconjugation of the β hydrogens, provides a preferred explanation of the tert-butyl solvolysis results

  10. tert-Butyl 6-bromo-1,4-dimethyl-9H-carbazole-9-carboxylate

    Directory of Open Access Journals (Sweden)

    Jean-François Lohier

    2010-08-01

    Full Text Available The title compound, C19H20BrNO2, consists of a carbazole skeleton with methyl groups at positions 1 and 4, a protecting group located at the N atom and a Br atom at position 6. The pyrrole ring is oriented at dihedral angles of 1.27 (7 and 4.86 (7° with respect to the adjacent benzene rings. The dihedral angle between the benzene rings is 5.11 (7. The crystal structure is determined mainly by intramolecular C—H...O and intermolecular π–π interactions. π-stacking between adjacent molecules forms columns with a parallel arrangement of the carbazole ring systems. The presence of the tert-butoxycarbonyl group on the carbazole N atom and the intramolecular hydrogen bond induce a particular conformation of the exocyclic N—C bond within the molecule.

  11. 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.

  12. INFLUENCE OF THE ISOBUTENE METHANOL RATIO AND OF THE METHYL TERT-BUTYL ETHER CONTENT ON THE REACTION-RATE OF THE SYNTHESIS OF METHYL TERT-BUTYL ETHER

    NARCIS (Netherlands)

    PANNEMAN, HJ; BEENACKERS, AACM

    1995-01-01

    The forward reaction rate constant of the MtBE synthesis was determined for different reaction mixture compositions. The forward rate constant decreases continuously with increasing isobutene/methanol ratio, while an increase in reaction rate constant is observed with an increasing amount of MtBE in

  13. Structure of methylene chloride addition product to zirconium tetrachloride complex with 1-tert.-butyl-2,4,4-trimethyl-2-thio-trimethylsilyl-1,3,2,4-diazaphosphasilatedine

    International Nuclear Information System (INIS)

    Brusilovets, A.I.; Rusanov, Eh.B.; Chernega, A.N.

    1995-01-01

    Complex of zirconium tetrachloride with 1-tert.-butyl-2,4,4-trimethyl--2-thio-3-trimethyl-silyl-1,3,2,4-diazaphosphasilatedine interacts with methylene chloride with formation of bis[3-tert.-butyl-2,4,4-trimethyl-1--trimethylsilyl-2-chloremethylthio-1,3,2,4-diazaphosphasilatedinium] decachlorodizirconate. Specific features of crystal and molecular structure of the compound prepared have been studied by X-ray diffraction method. 21 refs.; 2 figs.; 2 tabs

  14. Substituted 2,2′-bipyridines by nickel-catalysis: 4,4′-di-tert-butyl-2,2′-bipyridine

    OpenAIRE

    Buonomo, Joseph A.; Everson, Daniel A.; Weix, Daniel J.

    2013-01-01

    A simple, ligand-free synthesis of the important bipyridyl ligand 4,4′-di-tert-butyl-2,2′-bipyridine is presented. 5,5′-bis(trifluoromethyl)-2,2′-bipyridine is also synthesized by the same protocol. The syntheses efficiently couple the parent 2-chlorpyridies by a nickel-catalyzed dimerization with manganese powder as the terminal reductant.

  15. Substituted 2,2′-bipyridines by nickel-catalysis: 4,4′-di-tert-butyl-2,2′-bipyridine

    Science.gov (United States)

    Buonomo, Joseph A.; Everson, Daniel A.; Weix, Daniel J.

    2014-01-01

    A simple, ligand-free synthesis of the important bipyridyl ligand 4,4′-di-tert-butyl-2,2′-bipyridine is presented. 5,5′-bis(trifluoromethyl)-2,2′-bipyridine is also synthesized by the same protocol. The syntheses efficiently couple the parent 2-chlorpyridies by a nickel-catalyzed dimerization with manganese powder as the terminal reductant. PMID:25221358

  16. Thermochemical studies on two alkyl-bulky substituted xanthene derivatives: 9,9-dimethylxanthene and 2,7-di-tert-butyl-9,9-dimethylxanthene

    International Nuclear Information System (INIS)

    Freitas, Vera L.S.; Gomes, José R.B.; Ribeiro da Silva, Maria D.M.C.

    2017-01-01

    Highlights: • Energetic characterization of two alkyl-bulky substituted xanthene derivatives. • Massic energies of combustion of xanthene derivatives. • Enthalpies of sublimation determined by vacuum drop microcalorimetry technique. • Temperature-vapour pressure dependence by mass-loss Knudsen effusion method. • Gas-phase enthalpies of formation of alkyl xanthene derivatives. - Abstract: Thermodynamic properties of 9,9-dimethylxanthene and 2,7-di-tert-butyl-9,9-dimethylxanthene for the condensed and gas states were derived from experimental and computational studies. Static-bomb combustion calorimetry, vacuum drop microcalorimetry and the Knudsen effusion techniques were used. Computational calculations of the enthalpies of hypothetical reactions in the gaseous phase, using the G3(MP2)//B3LYP composite method, were performed for the two xanthene derivatives. Natural bond orbital (NBO) calculations were also performed to ascertain the structure and reactivity of these compounds. The energetic effects caused by replacing hydrogen atoms in the xanthene moiety by methyl and tert-butyl groups yielding 9,9-dimethylxanthene and 2,7-di-tert-butyl-9,9-dimethylxanthene species were determined from direct comparison of their standard (p o = 0.1 MPa) molar enthalpies of formation in the gaseous phase, at T = 298.15 K.

  17. Long term studies on the anaerobic biodegradability of MTBE and other gasoline ethers

    DEFF Research Database (Denmark)

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

    2009-01-01

    to investigate the anaerobic biodegradability of MTBE and other gasoline ethers. Inoculums collected from various environments were used, along with different electron acceptors. Only one set of the batch experiments showed a 30-60% conversion of MTBE to tert-butyl alcohol under Fe(III)-reducing conditions...

  18. Methyl tert-Butyl Ether (MTBE) - Its Movement and Fate in the Environment and Potential for Natural Attenuation

    Science.gov (United States)

    1999-10-01

    but at varying rates, by indigenous microbiota . Normal alkanes of low molecular weight (C-8 to C-22) are metabolized most rapidly, followed by...confirmed that TBA degradation occurred at a rate slower than MTBE degradation. Pure bacterial cultures isolated from activated sludge and the fruit of...isolated from activated sludge and fruit of the Gingko tree. They have been classified as belonging to the genuses Methlobacterium, Rhodococcus, and

  19. 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...

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

    International Nuclear Information System (INIS)

    Seddigi, Zaki S.; Bumajdad, Ali; Ansari, Shahid P.; Ahmed, Saleh A.; Danish, Ekram Y.; Yarkandi, Naeema H.; Ahmed, Shakeel

    2014-01-01

    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 2 sorptiometry study. The XPS results confirmed the structure of the Pd CeO 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 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

  1. 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.

  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. Interactions of poly(tert-butyl acrylate)-poly(styrene) diblock copolymers with lipids at the air-water interface.

    Science.gov (United States)

    Mudgil, Poonam; Dennis, Gary R; Millar, Thomas J

    2006-08-29

    Diblock copolymers with hydrophilic poly(tert-butyl acrylate) (PtBA) and hydrophobic poly(styrene) (PS) blocks were synthesized with a view to use them as a surfactant in tear film for increasing the ocular comfort in dry eye syndrome. Interactions of six PtBA-PS copolymers with four important lipids found in the tear film, namely cholesterol, cholesteryl palmitate, dipalmitoyl phosphatidylcholine, and phosphatidylinositol, were studied at the air-water interface using a Langmuir trough. Thermodynamics of mixing of the copolymers and the lipids in the mixed monolayers was determined by calculating excess free energy of mixing. The diblock copolymers showed repulsive interactions with cholesteol and cholesteryl palmitate, near neutral interactions with dipalmitoyl phosphatidylcholine, and attractive interactions with phosphatidylinositol. The lipids interacted with the PS component of the copolymer. The results indicate that a copolymer with a small hydrophilic group and a big hydrophobic group can be a likely candidate for forming stable interactions with the lipids present in the tear film and hence increase the ocular comfort.

  5. Electrochemical and Spin-Trapping Properties of para-substituted α-Phenyl-N-tert-butyl Nitrones

    International Nuclear Information System (INIS)

    Rosselin, Marie; Tuccio, Béatrice; Pério, Pierre; Villamena, Frederick A.; Fabre, Paul-Louis; Durand, Grégory

    2016-01-01

    Nitrones are known both as therapeutic antioxidants and efficient spin-traps. In this work, the redox behavior of various para-substituted α-phenyl-N-tert-butyl nitrones (PBN) was studied by cyclic voltammetry. The polar effect of the substituents was found to correlate with the electrochemical properties of the nitronyl function. Compounds bearing an electron-withdrawing group were more easily reduced than those having an electron-donating group and an opposite trend was observed for the oxidation. Ease of oxidation was also computationally rationalized using DFT approach showing increased ease of oxidation with electron donating functionalities. Since electrochemical properties of nitrones are known to correlate with biological properties, this work provides insights in the design of potent nitrone antioxidants. Using cyclic voltammetry the relative rate of superoxide trapping by nitrones was investigated and compared to the classical antioxidant BHT. The determination of the relative rate of phenyl radical trapping was also carried out but showed no clear correlation with the nature of the substituents. This indicates the absence of a polar effect in agreement with previous data and further supports the intermediate nature, that is, non- or weakly nucleophile, of phenyl radical. On the contrary kinetics of hydroxymethyl radical trapping was found to correlate with the nature of the substituents, demonstrating the nucleophilic nature of its addition onto nitrones.

  6. Synthesis, characterization and gas separation properties of novel polyimides containing cardo and tert-butyl-m-terphenyl moieties

    Directory of Open Access Journals (Sweden)

    L. A. Bermejo

    2018-05-01

    Full Text Available A series of aromatic polyimides has been obtained by the reaction of two dianhydrides, the commercial 2,2′-bis(3,4-dicarboxyphenylhexafluoropropane dianhydride (6FDA and another having a 5′-tert-butyl-m-terphenyl moiety (BTPDA, with several diamines, including two that have a cardo structure (derived from 9H-fluorene, one of them bearing methyl groups ortho to the amino functionalities (TMeCardo. The solubility, and also the thermal, mechanical, and gas separation properties of the corresponding polyimide membranes were evaluated and compared in order to explore the effect of the different groups in the polyimide backbone. The novel polyimides, which were derived from BTPDA and the cardo diamines, showed high thermal stability, excellent solubility in organic solvents and good gas separation properties, especially the polyimide that bore the ortho methyl substituents. The behavior was especially good for the pair O2/N2, where the TMeCardo polymer overpassed the Robeson upper bound.

  7. Characterization and photoconductivity study of well-defined C60 terminated poly(tert-butyl acrylate-b-styrene)

    International Nuclear Information System (INIS)

    Yang Dong; Li Lang; Wang Changchun

    2004-01-01

    Atom transfer radical polymerization (ATRP) catalyzed by N,N',N',N'',N''-pentamethyldiethylenetriamine (PMDETA)/CuBr was performed to synthesize poly (tert-butyl acrylate) (PtBA-Br) with predesigned molecular weight and narrow polydispersity. Using the PtBA-Br as macroinitiator, the PtBA-block-PS copolymer was prepared through ATRP. After terminated bromine atom was converted to end-functional azide group (P(tBA-b-St)-N 3 ), C 60 end-capped PtBA-PS block copolymers (P(tBA-b-St)-C 60 ) were synthesized by reacting C 60 with P(tBA-b-St)-N 3 . GPC characterizations showed that C 60 was chemically bonded to the end of P(tBA-b-St) chain and the products were mono-substituted. FT-IR, UV-Vis measurements confirmed that hydrolysis of P(tBA-b-St)-C 60 resulted in amphiphilic C 60 end-capped PAA-PS block copolymers. In additional, the photoconductivity of P(tBA-b-St)-C 60 was measured

  8. Synthesis, Crystal Growth, Spectroscopic and Electrical Properties of 5-tert-Butyl-1,2,3-trinitrobenzene

    Directory of Open Access Journals (Sweden)

    S. Sahaya Jude Dhas

    2013-01-01

    Full Text Available 5-tert-Butyl-1,2,3-trinitrobenzene (TBTB was synthesized and characterized by NMR so as to confirm the structure. Single crystals were obtained from methanol by solvent evaporation technique at room temperature. Optically transparent single crystals with dimension up to 17×4×3 mm3 have been grown by submerged seed solution method within a period of 30 days. The modes of vibration of different molecular groups present in the title compound were identified by FTIR and FT-Raman spectral analyses, and it was found with the tabulation that both of the spectral vibrations are very close to each other confirming the existence of specific functional groups in the crystal. Optical behaviour of the crystal was analyzed by UV-Vis absorption studies, and the value of the optical band gap energy (Eg of the crystal has been determined using the optical absorption spectrum. The dielectric behaviour and AC conductivity of the grown crystals were also analyzed, and it is shown that both properties vary with respect to frequency and do not vary in accordance with temperature.

  9. Bis(formylphenolatocobalt(II-Mediated Alternating Radical Copolymerization of tert-Butyl 2-Trifluoromethylacrylate with Vinyl Acetate

    Directory of Open Access Journals (Sweden)

    Sanjib Banerjee

    2017-12-01

    Full Text Available The organometallic-mediated radical polymerization (OMRP of vinyl acetate (VAc and its OMR copolymerization (OMRcoP with tert-butyl 2-trifluoromethylacrylate (MAF-TBE mediated by Co(SAL2 (SAL = 2-formylphenolato or deprotonated salicylaldehyde produced relatively well-defined PVAc and poly(VAc-alt-MAF-TBE copolymers at moderate temperature (<40 °C in bulk. The resulting alternating copolymer was characterized by 1H-, 13C- and 19F-nuclear magnetic resonance (NMR spectroscopies, and by size exclusion chromatography. The linear first-order kinetic plot, the linear evolutions of the molar mass with total monomer conversion, and the relatively low dispersity (Đ~1.55 of the resulting copolymers suggest that this cobalt complex provides some degree of control over the copolymerization of VAc and MAF-TBE. Compared to the previously investigated cobalt complex OMRP mediators having a fully oxygen-based first coordination sphere, this study emphasizes a few peculiarities of Co(SAL2: a lower ability to trap radical chains as compared to Co(acac2 and the absence of catalytic chain transfer reactions, which dominates polymerizations carried in the presence of 9-oxyphenalenone cobalt derivative.

  10. Protective Effects of Alkaloid Compounds from Nelumbinis Plumula on tert-Butyl Hydroperoxide-Induced Oxidative Stress

    Directory of Open Access Journals (Sweden)

    Ze-Bin Guo

    2013-08-01

    Full Text Available This study was conducted to investigate the effect of Nelumbinis Plumula total alkaloid (NPA and its main alkaloid components on oxidative stress induced by tert-butyl hydroperoxide (t-BHP in the human hepatocellular HepG2 cell line. According to HPLC analysis, several major alkaloid compounds such as liensinine, isoliensinine and neferine were present in NPA. The cytotoxic effects in 0.55 mM t-BHP-induced HepG2 cells were significantly inhibited by NPA and the major compound in NPA, neferine, showed the strongest activities. The protective effect of neferine against oxidative stress induced by t-BHP may be associated with decreased ROS formation, TBARS generation, LDH release and increased GSH levels, suggesting their involvement of the cytoprotective on oxidative stress. The effects were comparable with quercetin, which was used as positive control. Overall, total alkaloid and alkaloid compounds from Nelumbinis Plumula displayed a significant cytoprotective effect against oxidative stress. Further study is needed to elucidate the relationship between the chemical structures of the components in NPA and their protective effect on oxidative stress.

  11. 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.

  12. Sulfuric acid functional zirconium (or aluminum) incorporated mesoporous MCM-48 solid acid catalysts for alkylation of phenol with tert-butyl alcohol

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Tingshun, E-mail: tshjiang@mail.ujs.edu.cn; Cheng, Jinlian; Liu, Wangping; Fu, Lie; Zhou, Xuping; Zhao, Qian; Yin, Hengbo

    2014-10-15

    Several zirconium (or aluminum) incorporated mesoporous MCM-48 solid acid catalysts (SO{sub 4}{sup 2−}/Zr-MCM-48 and SO{sub 4}{sup 2−}/Al-MCM-48) were prepared by the impregnation method and their physicochemical properties were characterized by means of XRD, FT-IR, TEM, NH{sub 3}-TPD and N{sub 2} physical adsorption. Also, the catalytic activities of these solid acid catalysts were evaluated by the alkylation of phenol with tert-butyl alcohol. The effect of weight hour space velocity (WHSV), reaction time and reaction temperature on catalytic properties was also studied. The results show that the SO{sub 4}{sup 2−}/Zr-MCM-48 and SO{sub 4}{sup 2−}/Al-MCM-48 still have good mesoporous structure and long range ordering. Compared with the Zr (or Al)–MCM-48 samples, SO{sub 4}{sup 2−}/Zr-MCM-48 and SO{sub 4}{sup 2−}/Al-MCM-48 solid acid catalysts have strong acidity and exhibit high activities in alkylation reaction of phenol with tert-butyl alcohol. The SO{sub 4}{sup 2−}/Zr-MCM-48-25 (molar ratio of Si/Zr=0.04) catalyst was found to be the most promising and gave the highest phenol conversion among all catalysts. A maximum phenol conversion of 91.6% with 4-tert-butyl phenol (4-TBP) selectivity of 81.8% was achieved when the molar ratio of tert-butyl alcohol:phenol is 2:1, reaction time is 2 h, the WHSV is 2 h{sup −1} and the reaction temperature is 140 °C. - Highlights: • Sulfuric acid functional mesoporous solid acid catalysts were prepared via impregnation method. • The alkylation of phenol with tert-butyl alcohol was carried out over these solid acid catalysts. • The catalytic activity of SO{sub 4}{sup 2−}/Zr-MCM-48-25 catalyst is much higher than that of the others. • A maximum phenol conversion of 91.6% was achieved under optimum reaction conditions for SO{sub 4}{sup 2−}/Zr-MCM-48-25.

  13. Sulfuric acid functional zirconium (or aluminum) incorporated mesoporous MCM-48 solid acid catalysts for alkylation of phenol with tert-butyl alcohol

    International Nuclear Information System (INIS)

    Jiang, Tingshun; Cheng, Jinlian; Liu, Wangping; Fu, Lie; Zhou, Xuping; Zhao, Qian; Yin, Hengbo

    2014-01-01

    Several zirconium (or aluminum) incorporated mesoporous MCM-48 solid acid catalysts (SO 4 2− /Zr-MCM-48 and SO 4 2− /Al-MCM-48) were prepared by the impregnation method and their physicochemical properties were characterized by means of XRD, FT-IR, TEM, NH 3 -TPD and N 2 physical adsorption. Also, the catalytic activities of these solid acid catalysts were evaluated by the alkylation of phenol with tert-butyl alcohol. The effect of weight hour space velocity (WHSV), reaction time and reaction temperature on catalytic properties was also studied. The results show that the SO 4 2− /Zr-MCM-48 and SO 4 2− /Al-MCM-48 still have good mesoporous structure and long range ordering. Compared with the Zr (or Al)–MCM-48 samples, SO 4 2− /Zr-MCM-48 and SO 4 2− /Al-MCM-48 solid acid catalysts have strong acidity and exhibit high activities in alkylation reaction of phenol with tert-butyl alcohol. The SO 4 2− /Zr-MCM-48-25 (molar ratio of Si/Zr=0.04) catalyst was found to be the most promising and gave the highest phenol conversion among all catalysts. A maximum phenol conversion of 91.6% with 4-tert-butyl phenol (4-TBP) selectivity of 81.8% was achieved when the molar ratio of tert-butyl alcohol:phenol is 2:1, reaction time is 2 h, the WHSV is 2 h −1 and the reaction temperature is 140 °C. - Highlights: • Sulfuric acid functional mesoporous solid acid catalysts were prepared via impregnation method. • The alkylation of phenol with tert-butyl alcohol was carried out over these solid acid catalysts. • The catalytic activity of SO 4 2− /Zr-MCM-48-25 catalyst is much higher than that of the others. • A maximum phenol conversion of 91.6% was achieved under optimum reaction conditions for SO 4 2− /Zr-MCM-48-25

  14. 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.

  15. SIRT1 exhibits antioxidative effects in HT22 cells induced by tert-butyl alcohol.

    Science.gov (United States)

    Ma, Junxiang; Song, Dongmei; Zhang, Yuanyuan; Chen, Li; Zhang, Shixuan; Jia, Jiaxin; Chen, Tian; Guo, Caixia; Tian, Lin; Gao, Ai; Niu, Piye

    2018-02-01

    Tertiary butyl alcohol (TBA) is a principal metabolite of methyl tertiary-butyl ether (MTBE), a common pollutant worldwide in the ground or underground water, which is found to produce nervous system damage. Nevertheless, few data regarding the effects of TBA has been reported. Studies indicated that oxidative stress plays a pivotal role in MTBE neurotoxic mechanism. Sirtuin 1 (SIRT1) has been reported to exert a neuroprotective effect on various neurologic diseases via resistance to oxidative stress by deacetylating its substrates. In this study, we examined levels of oxidative stress after exposure to TBA for 6 h in HT22 cells and HT22 cells with SIRT1 silencing (transfected with SIRT1 siRNA) or high expression (preconditioned with agonists SRT1720). We found that TBA activated oxidative stress by increasing generation of intracellular reactive oxygen species (ROS), malondialdehyde (MDA) and Oxidized glutathione (GSSG), and decreasing contents of superoxide dismutase (SOD) and glutathione reductase (GSH). In additional, levels of TBA-induced oxidative stress were aggravated when SIRT1 silenced but alleviated when SIRT1 enhanced. Our study indicated that SIRT1 mitigated oxidative stress induced by TBA. © 2017 Wiley Periodicals, Inc.

  16. The Chemistry and Flow Dynamics of Molecular Biological Tools Used to Confirm In Situ Bioremediation of Benzene, TBA, and MTBE

    Science.gov (United States)

    North, K. P.; Mackay, D. M.; Scow, K. M.

    2010-12-01

    In situ bioremediation has typically been confirmed by collecting sediment and groundwater samples to directly demonstrate a degradation process in a laboratory microcosm. However, recent advances in molecular biological tools present options for demonstrating degradation processes with field-based tools that are less time-consuming. We have been investigating the capability of some of these molecular biological tools to evaluate in situ biodegradation of tert-butyl alcohol (TBA), methyl tert-butyl ether (MTBE), and benzene at two field sites in California. At both sites, we have deployed Bio-Traps® (“traps”), made of Bio-Sep® beads in slotted PVC pipe, which provide ideal environments for microbial colonization. Stable Isotope Probing can be accomplished by sorbing the13C-labeled organic contaminant of concern onto Bio-Sep® beads (“baiting”); incorporation of 13C into the biomass collected by the trap would indicate that the microbial community was capable of degrading the labeled compound. In addition, we examined the chemistry and flow dynamics of these traps and present those results here. We performed a field experiment and a lab experiment to, in part, define the rate that different baits leached off various traps. At a TBA- and MTBE-contaminated site at Vandenberg AFB, Lompoc, CA, the TBA-dominant plume was effectively treated by recirculation/oxygenation of groundwater, decreasing TBA and MTBE concentrations to detection limits along predicted flowpaths created by two pairs of recirculation wells. We used the generated aerobic treatment zone to deploy traps baited with 13C-labeled MTBE or TBA in a novel, ex situ experimental setup. The groundwater flow extracted from the aerobic treatment zone was split through several chambers, each containing a trap and monitoring of influent and effluent. The chamber effluent was measured throughout a six-week deployment and analyzed for both TBA and MTBE; the majority of mass leached from the baited traps did

  17. Epigenetic and Transcriptional Modifications in Repetitive Elements in Petrol Station Workers Exposed to Benzene and MTBE

    Directory of Open Access Journals (Sweden)

    Federica Rota

    2018-04-01

    Full Text Available Benzene, a known human carcinogen, and methyl tert-butyl ether (MTBE, not classifiable as to its carcinogenicity, are fuel-related pollutants. This study investigated the effect of these chemicals on epigenetic and transcriptional alterations in DNA repetitive elements. In 89 petrol station workers and 90 non-occupationally exposed subjects the transcriptional activity of retrotransposons (LINE-1, Alu, the methylation on repeated-element DNA, and of H3K9 histone, were investigated in peripheral blood lymphocytes. Median work shift exposure to benzene and MTBE was 59 and 408 µg/m3 in petrol station workers, and 4 and 3.5 µg/m3, in controls. Urinary benzene (BEN-U, S-phenylmercapturic acid, and MTBE were significantly higher in workers than in controls, while trans,trans-muconic acid (tt-MA was comparable between the two groups. Increased BEN-U was associated with increased Alu-Y and Alu-J expression; moreover, increased tt-MA was associated with increased Alu-Y and Alu-J and LINE-1 (L1-5′UTR expression. Among repetitive element methylation, only L1-Pa5 was hypomethylated in petrol station workers compared to controls. While L1-Ta and Alu-YD6 methylation was not associated with benzene exposure, a negative association with urinary MTBE was observed. The methylation status of histone H3K9 was not associated with either benzene or MTBE exposure. Overall, these findings only partially support previous observations linking benzene exposure with global DNA hypomethylation.

  18. Salvianic acid A sodium protects HUVEC cells against tert-butyl hydroperoxide induced oxidative injury via mitochondria-dependent pathway.

    Science.gov (United States)

    Jia, Dan; Li, Tian; Chen, Xiaofei; Ding, Xuan; Chai, Yifeng; Chen, Alex F; Zhu, Zhenyu; Zhang, Chuan

    2018-01-05

    Salvianic acid A (Danshensu) is a major water-soluble component extracted from Salvia miltiorrhiza (Danshen), which has been widely used in clinic in China for treatment of cardiovascular diseases (CVDs). This study aimed to investigate the protective effects of salvianic acid A sodium (SAAS) against tert-butyl hydroperoxide (t-BHP) induced human umbilical vein endothelial cell (HUVEC) oxidative injury and the underlying molecular mechanisms. In the antioxidant activity-assessing model, SAAS pretreatment significantly ameliorated the cell growth inhibition and apoptosis induced by t-BHP. An ultra-performance liquid chromatography/quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS) based-metabolic profiling was developed to investigate the metabolic changes of HUVEC cells in response to t-BHP and SAAS. The results revealed that t-BHP injury upregulated 13 metabolites mainly involved in tryptophan metabolism and phenylalanine metabolism which were highly correlated with mitochondrial function and oxidative stress, and 50 μM SAAS pretreatment effectively reversed these metabolic changes. Further biomedical research indicated that SAAS pretreatment reduced the t-BHP induced increase of lactate dehydrogenase (LDH), intracellular reactive oxygen species (ROS), malondialdehyde (MDA) and mitochondrial membrane potential (MMP), and the decrease of key antioxidant enzymes through mitochondria antioxidative pathways via JAK2/STAT3 and PI3K/Akt/GSK-3β signalings. Taken together, our results suggested that SAAS may protect HUVEC cells against t-BHP induced oxidative injury via mitochondrial antioxidative defense system. Copyright © 2017 Elsevier B.V. All rights reserved.

  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. 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.

  1. Heterogeneous catalytic epoxidation of C/sub 8/-C/sub 1/4 olefins by tert. -butyl hydroperoxide

    Energy Technology Data Exchange (ETDEWEB)

    Dahlmann, J; Hoeft, E; Boeden, H F; Dilcher, H

    1979-09-01

    Heterogeneous catalytic epoxidation of C/sub 8/-C/sub 14/ olefins by tert.-butyl hydroperoxide (TBHP) avoids large product losses to side reactions, associated with the use of homogeneous catalysts, such as Mo(CO)/sub 6/. With an unsupported MoO/sub 3/ catalyst, 48% TBHP conversion was achieved after one hour (vs. 24% after two hours for Mo(CO)/sub 6/) in 1-octene epoxidation at 90/sup 0/C and 2:1:3 octene/TBHP/toluene (solvent) molar ratio. The use of silica-supported catalysts, such as Bi/sub 9/PMo/sub 12/O/sub 52//30% SiO/sub 2/ (ACN, an industrial catalyst for acrylonitrile), MoO/sub 3//30% SiO/sub 2/ (D-1), 3MoO/sub 3/-Sb/sub 2/O/sub 5//50% SiO/sub 2/ (D-2), or 2MoO/sub 3/-As/sub 2/O/sub 3//50% SiO/sub 2/ (D-3) increased the conversion to 68, 67, 70, and 73%, respectively, with up to 95-99% selectivities for the epoxide. Under optimum conditions of 3:1 olefin/TBHP, 110/sup 0/C, and 2-4 g/l. catalyst, TBHP conversions in epoxidation of 1-tetradecene in a batch reactor over ACN, D-2, and D-3 after two hours were 94, 88, and 91%, respectively, but they decreased to 52, 78, and 79%, respectively, after five two-hour operating cycles. In epoxidation of 1-decene or a mixture of decene isomers (a model for the industrial olefin mixtures obtained by paraffin dehydrogenation via the Parex process) carried out in a continuous flow reactor over the D-3 catalyst at 90/sup 0/-110/sup 0/C, stable catalytic activities with TBHP conversions of approx. 90% and 90-96% selectivities for epoxides were observed for about 900 hr.

  2. Formation of zinc-peptide spherical microparticles during lyophilization from tert-butyl alcohol/water co-solvent system.

    Science.gov (United States)

    Qian, Feng; Ni, Nina; Chen, Jia-Wen; Desikan, Sridhar; Naringrekar, Vijay; Hussain, Munir A; Barbour, Nancy P; Smith, Ronald L

    2008-12-01

    To understand the mechanism of spherical microparticle formation during lyophilizing a tert-Butyl alcohol (TBA)/water solution of a zinc peptide adduct. A small peptide, PC-1, as well as zinc PC-1 at (3:2) and (3:1) ratios, were dissolved in 44% (wt.%) of TBA/water, gradually frozen to -50 degrees C over 2 h ("typical freezing step"), annealed at -20 degrees C for 6 h ("annealing step"), and subsequently lyophilized with primary and secondary drying. Zinc peptide (3:1) lyophile was also prepared with quench cooling instead of the typical freezing step, or without the annealing step. Other TBA concentrations, i.e., 25%, 35%, 54% and 65%, were used to make the zinc peptide (3:1) adduct lyophile with the typical freezing and annealing steps. The obtained lyophile was analyzed by Scanning Electron Microscopy (SEM). The zinc peptide solutions in TBA/water were analyzed by Differential Scanning Calorimeter (DSC). The surface tension of the TBA/water co-solvent system was measured by a pendant drop shape method. With typical freezing and annealing steps, the free peptide lyophile showed porous network-like structure that is commonly seen in lyophilized products. However, with increasing the zinc to peptide ratio, uniform particles were gradually evolved. Zinc peptide (3:1) adduct lyophiles obtained from 25%, 35% and 44% TBA exhibit a distinctive morphology of uniform and spherical microparticles with diameters of approximately 3-4 microm, and the spherical zinc peptide particles are more predominant when the TBA level approaches 20%. Adopting quench cooling in the lyophilization cycle leads to irregular shape fine powders, and eliminating the annealing step causes rough particles surface. When TBA concentration increases above 54%, the lyophiles demonstrate primarily irregular shape particles. A proposed mechanism of spherical particle formation of the 3:1 zinc peptide encompasses the freezing of a TBA/water solution (20-70% TBA) causing the formation of a TBA hydrate

  3. Synthesis and complexation properties towards uranyl cation of carboxylic acid derivatives of p-tert-butyl-calix[6]arene

    International Nuclear Information System (INIS)

    Souane, R.

    2005-03-01

    In the fuel reprocessing plants radioactive metals, and more particularly, uranium in UO 2 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 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 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 (ΔlogΒ110 = 4.3), and than the effect of the groupings nitro in para position has low influence on the complexation of UO 2 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. (author)

  4. 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 k cat /K m , 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.

  5. Biosynthesis of tert-butyl (3R,5S)-6-chloro-3,5-dihydroxyhexanoate by carbonyl reductase from Rhodosporidium toruloides in mono and biphasic media.

    Science.gov (United States)

    Liu, Zhi-Qiang; Wu, Lin; Zheng, Ling; Wang, Wen-Zhong; Zhang, Xiao-Jian; Jin, Li-Qun; Zheng, Yu-Guo

    2018-02-01

    tert-Butyl (3R,5S)-6-chloro-3,5-dihydroxyhexanoate ((3R,5S)-CDHH) is the key intermediate for synthesis of atorvastatin and rosuvastatin. Carbonyl reductase exhibits excellent activity toward tert-butyl (S)-6-chloro-5-hydroxy-3-oxohexanoate ((S)-CHOH) to synthesize (3R,5S)-CDHH. In this study, a whole cell biosynthesis reaction system to produce (3R,5S)-CDHH was constructed in organic solvents. A solution of 10% (v/v) Tween-80 was introduced to the reaction system as a co-solvent, which greatly enhanced biotransformation process, giving 98.9% yield, >99% ee and 1.8-fold higher space time yield in 5 h bioconversion of 1 M (S)-CHOH, compared with 98.7% yield and >99% ee in 9 h bioconversion of a purely aqueous reaction system. Moreover, a water-octanol biphasic reaction system was built and 20% of octanol was added as reservoir of substrate resulting in 98% yield, >99% ee and 4.08 mmol L -1  h -1  g -1 (wet cell weight) space time yield. This study paved a way for the whole cell biosynthesis of (3R,5S)-CDHH in mono and biphasic media. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Antioxidant and hepatoprotective effects of Capparis spinosa L. fractions and Quercetin on tert-butyl hydroperoxide- induced acute liver damage in mice

    Directory of Open Access Journals (Sweden)

    Heibatullah Kalantari

    2018-01-01

    Full Text Available The present study investigates the antioxidant and hepatoprotective effects of Capparis spinosa L. and Quercetin in tert-butyl hydroperoxide (t-BHP induced acute liver damage. Different fractions of C. spinosa were examined for total phenolic content and antioxidant property. Among these fractions, hydroalcoholic extract was used to assess the hepatoprotective effect in tert-butyl hydroperoxide (t-BHP induced hepatotoxicity model by determining serum biochemical markers, sleeping time and antioxidant assay such as reduced glutathione (GSH as well as histopathological examination of liver tissues. The total phenolic and Quercetin contents of hydroalcoholic fraction were significantly higher than other fractions. It also showed high antioxidant activity. Pretreatment with hydroalcoholic fraction at the dose of 400 mg/kg and Quercetin at the dose of 20 mg/kg showed liver protection against t-BHP induced hepatic injury, as it was evident by a significant decrease in serum enzymes marker, sleeping time and MDA and an increase in the GSH, SOD and CAT activities confirmed by pathology tests. The final results ascertained the hepatoprotective and antioxidant effects of C. spinosa and Quercetin in a dose-dependent manner. Moreover, this study suggests that possible mechanism of this protection may be associated with its property of scavenging free radicals which may be due to the presence of phenolic compounds.

  7. 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.

  8. 6,6'-(1E,1'E-((1R,2R-1,2-Diphenylethane-1,2-diylbis(azan-1-yl-1-ylidenebis(methan-1-yl-1-ylidenebis(2-tert-butyl-4-((trimethylsilylethynylphenol

    Directory of Open Access Journals (Sweden)

    David Díaz Díaz

    2013-03-01

    Full Text Available Functionalizable salen derivative, 6,6'-(1E,1'E-((1R,2R-1,2-diphenylethane-1,2-diylbis(azan-1-yl-1-ylidenebis(methan-1-yl-1-ylidenebis(2-tert-butyl-4-((trimethylsilyl ethyn-ylphenol (3, was synthesized by condensation between (1R,2R-1,2-diphenylethane-1,2-diamine (2 and 3-tert-butyl-2-hydroxy-5-((trimethylsilylethynyl benzaldehyde (1 under refluxing conditions. The title compound was characterized by 1H-NMR, 13C-NMR, FT-IR, high-resolution mass spectrometry, optical rotation and melting point determination.

  9. 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...

  10. Synthesis and dynamic NMR study of ketenimines derived from tert-butyl isocyanide, alkyl 2-arylamino-2-oxo-acetates, and dialkyl acetylenedicarboxylates.

    Science.gov (United States)

    Yavari, Issa; Nasiri, Farough; Djahaniani, Horieh

    2004-01-01

    The adduct produced in the reaction between tert-butyl isocyanide and dialkyl acetylenedicarboxylates was trapped by alkyl 2-arylamino-2-oxo-acetates. When the aryl group is 2-methyl-6-nitrophenyl or 2,6-di-isopropylphenyl, the product exists as two stable rotamers at room temperature as a result of restricted rotation around the Ar-N single bond. When the aryl group is 1-naphthyl or 8-quinolinyl, dynamic NMR effects are observed in the 1H NMR spectra. The calculated free-energy of activation for interconversion of the rotational isomers in 1-naphthyl and 8-quinolinyl derivatives amounts to about 99+/-2 and 68.5+/-2 kJ mol(-1), respectively.

  11. Synthesis, structural characterization and theoretical studies of a new Schiff base 4-(((3-(tert-Butyl)-(1-phenyl)pyrazol-5-yl) imino)methyl)phenol

    Science.gov (United States)

    Cuenú, Fernando; Londoño-Salazar, Jennifer; Torres, John Eduard; Abonia, Rodrigo; D'Vries, Richard F.

    2018-01-01

    4-(((3-(tert-Butyl)-(1-phenyl)pyrazol-5-yl)imino)methyl)phenol (4-OHFPz) was synthesized and characterized by FT-IR, MS, NMR, and single-crystal X-ray diffraction. Optimization of molecular geometry, vibrational frequencies, and chemical shifts were calculated by using the methods of density functional theory (DFT) with B3LYP and B3PW91 as functionals and Hartree-Fock with 6-311G++(d,p) as basis set using the GAUSSIAN 09 program package. With the VEDA 4 software, the vibrational frequencies were assigned in terms of the potential energy distribution (PED). The equilibrium geometries calculated by all methods were compared with X-ray diffraction results, indicating that the theoretical results matches well with the experimental ones. The data obtained from the vibrational analysis and the calculated NMR are consistent with the experimental spectra.

  12. Catalytic Activity of μ-Carbido-Dimeric Iron(IV) Octapropylporphyrazinate in the 3,5,7,2',4'-Pentahydroxyflavone Oxidation Reaction with tert-Butyl Hydroperoxide

    Science.gov (United States)

    Tyurin, D. V.; Zaitseva, S. V.; Kudrik, E. V.

    2018-05-01

    It is found for the first time that μ-carbido-dimeric iron(IV) octapropylporphyrazinate displays catalytic activity in the oxidation reaction of natural flavonol morin with tert-butyl hydroperoxide, with the catalyst being stable under conditions of the reaction. The kinetics of this reaction are studied. It is shown the reaction proceeds via tentative formation of a complex between the catalyst and the oxidant, followed by O‒O bond homolytic cleavage. The kinetics of the reaction is described in the coordinates of the Michaelis-Menten equation. A linear dependence of the apparent reaction rate constant on the concentration of the catalyst is observed, testifying to its participation in the limiting reaction step. The equilibrium constants and rates of interaction are found. A mechanism is proposed for the reaction on the basis of the experimental data.

  13. 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.

  14. Metabolism of the fungicide Denmert (S-n-butyl S'-p-tert-butyl-benzyl N-3-pyridyldithiocarbonimidate, S-1358) and Denmert sulfoxides in liver enzyme systems

    International Nuclear Information System (INIS)

    Ohkawa, Hideo; Okihara, Yukiko; Miyamoto, Junshi

    1976-01-01

    On incubation with rat liver microsomes plus MADPH, Denmert (S-n-butyl S'-p-tert-butylbenzyl N-3-pyridyldithiocarbonimidate) underwent at least two different types of oxidation; hydroxylation and sulfoxidation. Hydroxylation of Denmert at the tert-butyl group was one of the major metabolic attacks in mammalian metabolism. Sulfoxidation of Denmert gave two isomers of Denmert sulfoxides which were intermediates in the metabolism and readily transformed into 2-(3'-pyridylimino)-4-carboxylthiazolidine (HM) in the presence of L-cysteine without enzymatic mediation. This type of conjugation with cysteine appears to be a new class of metabolic reactions in mammals. Denmert S-oxide showed increased fungicidal activity when assayed in liquid cultures, but not on plant leaves. (auth.)

  15. 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.

  16. Multi-wall carbon nanotubes supported molybdenyl acetylacetonate: Efficient and highly reusable catalysts for epoxidation of alkenes with tert-butyl hydroperoxide

    Energy Technology Data Exchange (ETDEWEB)

    Esnaashari, Fariba [Department of Chemistry, Catalysis Division, University of Isfahan, Isfahan 81746-73441 (Iran, Islamic Republic of); Moghadam, Majid, E-mail: moghadamm@sci.ui.ac.ir [Department of Chemistry, Catalysis Division, University of Isfahan, Isfahan 81746-73441 (Iran, Islamic Republic of); Mirkhani, Valiollah, E-mail: mirkhani@sci.ui.ac.ir [Department of Chemistry, Catalysis Division, University of Isfahan, Isfahan 81746-73441 (Iran, Islamic Republic of); Tangestaninejad, Shahram; Mohammadpoor-Baltork, Iraj; Khosropour, Ahmad Reza; Zakeri, Maryam [Department of Chemistry, Catalysis Division, University of Isfahan, Isfahan 81746-73441 (Iran, Islamic Republic of)

    2012-11-15

    Efficient epoxidation of olefins catalyzed by MoO{sub 2}(acac){sub 2} supported on amines functionalized MWCNTs is reported. The MWCNTs bearing carboxylic acid groups were modified with 2-aminophenol and 2-aminothiophenol. These amine-MWCNTs act as bidentate ligand for attachment of Mo catalyst. These catalysts were characterized by elemental analysis, scanning electron microscopy, FT-IR and diffuse reflectance UV-Vis spectroscopic methods. The prepared catalysts were used for efficient epoxidation of different alkenes such as cyclic and linear ones with tert-butyl hydroperoxide in refluxing 1,2-dichloroethane. These heterogeneous catalysts can be reused several times without significant loss of their catalytic activity. Highlights: Black-Right-Pointing-Pointer Supporting of molybdenyl acetylacetonate on amine-modified MWCNTs. Black-Right-Pointing-Pointer Heterogeneous catalysts were prepared. Black-Right-Pointing-Pointer These catalysts were highly efficient in the epoxidation of alkenes with TBHP. Black-Right-Pointing-Pointer Makes the catalysts reusable.

  17. Multi-wall carbon nanotubes supported molybdenyl acetylacetonate: Efficient and highly reusable catalysts for epoxidation of alkenes with tert-butyl hydroperoxide

    International Nuclear Information System (INIS)

    Esnaashari, Fariba; Moghadam, Majid; Mirkhani, Valiollah; Tangestaninejad, Shahram; Mohammadpoor-Baltork, Iraj; Khosropour, Ahmad Reza; Zakeri, Maryam

    2012-01-01

    Efficient epoxidation of olefins catalyzed by MoO 2 (acac) 2 supported on amines functionalized MWCNTs is reported. The MWCNTs bearing carboxylic acid groups were modified with 2-aminophenol and 2-aminothiophenol. These amine–MWCNTs act as bidentate ligand for attachment of Mo catalyst. These catalysts were characterized by elemental analysis, scanning electron microscopy, FT-IR and diffuse reflectance UV–Vis spectroscopic methods. The prepared catalysts were used for efficient epoxidation of different alkenes such as cyclic and linear ones with tert-butyl hydroperoxide in refluxing 1,2-dichloroethane. These heterogeneous catalysts can be reused several times without significant loss of their catalytic activity. Highlights: ► Supporting of molybdenyl acetylacetonate on amine-modified MWCNTs. ► Heterogeneous catalysts were prepared. ► These catalysts were highly efficient in the epoxidation of alkenes with TBHP. ► Makes the catalysts reusable.

  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. Synthesis of 4-tert-Butyltoluene by Vapor Phase tert-Butylation of Toluene with tert-Butylalcohol over USY Zeolite

    Directory of Open Access Journals (Sweden)

    Yan Ming Shen

    2015-03-01

    Full Text Available Vapour phase tert-butylation of toluene with tert-butylalcohol was studied over ultra-stable Y zeolite (USY catalyst. The effects of reaction temperature, toluene/TBA molar ratio and liquid space velocity on conversion of toluene and selectivity for 4-tert-butyltoluene were studied. The deactivation and regeneration of the catalyst was also investigated. The results showed that the USY zeolite catalyst offered better toluene conversion of about 30 % and 4-tert-butyltoluene selectivity of about 89 % at the suitable reaction condition as follows: reaction temperature of 120 oC, toluene/TBA ratio of 2:1 and liquid space velocity of 2 ml/g·h. The clogging of mocropores by the formed carbon or oligomers was the main reason for the deactivation of the catalyst. By combustion at 550 oC, the catalyst just lost about 5 % in toluene conversion and about 2 % in PTBT selectivity. © 2015 BCREC UNDIP. All rights reservedReceived: 17th July 2014; Revised: 31st August 2014; Accepted: 3rd September 2014How to Cite: Shen, Y.M., Yuan, S., Fan, L., Liu, D.B., Li, S.F. (2015. Synthesis of 4-tert-Butyltoluene by Vapor Phase tert-Butylation of Toluene with tert-Butylalcohol over USY Zeolite. Bulletin of Chemical Reaction Engineering & Catalysis, 10 (1: 1-7. (doi:10.9767/bcrec.10.1.7140.1-7Permalink/DOI: http://dx.doi.org/10.9767/bcrec.10.1.7140.1-7

  20. Phase equilibrium properties of binary and ternary systems containing di-isopropyl ether + 1-butanol + benzene at 313.15 K

    International Nuclear Information System (INIS)

    Villamanan, Rosa M.; Martin, M. Carmen; Chamorro, Cesar R.; Villamanan, Miguel A.; Segovia, Jose J.

    2006-01-01

    (Vapour + liquid) equilibria data of (di-isopropyl ether + 1-butanol + benzene) (di-isopropyl ether + 1-butanol) and (1-butanol + benzene) have been measured at T = 313.15 K using an isothermal total pressure cell. Data reduction by Barker's method provides correlations for the excess molar Gibbs energy using the Margules equation for the binary systems and the Wohl expansion for the ternary. The Wilson, NRTL and UNIQUAC models have been applied successfully to both the binary and the ternary systems reported here

  1. Simultaneous analysis of tert-butylhydroquinone, tert-butylquinone, butylated hydroxytoluene, 2-tert-butyl-4-hydroxyanisole, 3-tert-butyl-4-hydroxyanisole, α-tocopherol, γ-tocopherol, and δ-tocopherol in edible oils by normal-phase high performance liquid chromatography.

    Science.gov (United States)

    Li, Jun; Bi, Yanlan; Sun, Shangde; Peng, Dan

    2017-11-01

    A normal-phase high performance liquid chromatography method for the simultaneous determination of tert-butylhydroquinone, tert-butylquinone, butylated hydroxytoluene, 2-tert-butyl-4-hydroxyanisole, 3-tert-butyl-4-hydroxyanisole, α-tocopherol, γ-tocopherol, and δ-tocopherol in edible oils was investigated. A silica column was used to separate the analytes with the gradient elution. An ultraviolet-visible detector was set at dual wavelengths mode (280 and 310nm). The column temperature was 30°C. The analytes were directly extracted with methanol. Results showed that the normal-phase high performance liquid chromatography method performed well with wide liner ranges (0.10∼500.00μg/mL, R 2 >0.9998), low limits of detection and quantitation (below 0.40 and 1.21μg/mL, respectively), and good recoveries (81.38∼102.34% in soybean oils and 83.03∼100.79% in lard, respectively). The reduction of tert-butylquinone caused by the reverse-phase high performance liquid chromatography during the injection was avoided with the current normal-phase method. The two isomers of butylated hydroxyanisole can also be separated with good resolution. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

    International Nuclear Information System (INIS)

    Ndolomingo, Matumuene Joe; Meijboom, Reinout

    2017-01-01

    Highlights: • Cu and Au on γ-Al 2 O 3 catalysts were prepared and characterized. • Benzyl alcohol oxidation to benzaldehyde was performed by tert-butyl hydroperoxide in the absence of any solvent using the prepared catalysts. • The as prepared catalysts exhibited good performance in terms of conversion and selectivity towards benzaldehyde. • The kinetics of the reaction was investigated; k app was proportional to the amount of nano catalyst and oxidant present in the system. • The catalysts was recycled and reused with neither significant loss of activity nor selectivity. - Abstract: Benzyl alcohol oxidation to benzaldehyde was performed by tert-butyl hydroperoxide (TBHP) in the absence of any solvent using γ-Al 2 O 3 supported copper and gold nanoparticles. Li 2 O 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), N 2 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

  3. Highly efficient enzymatic synthesis of tert-butyl (S)-6-chloro-5-hydroxy-3-oxohexanoate with a mutant alcohol dehydrogenase of Lactobacillus kefir.

    Science.gov (United States)

    He, Xiu-Juan; Chen, Shao-Yun; Wu, Jian-Ping; Yang, Li-Rong; Xu, Gang

    2015-11-01

    tert-Butyl (S)-6-chloro-5-hydroxy-3-oxohexanoate ((S)-CHOH) is a valuable chiral synthon, which is used for the synthesis of the cholesterol-lowering drugs atorvastatin and rosuvastatin. To date, only the alcohol dehydrogenases from Lactobacillus brevis (LbADH) and Lactobacillus kefir (LkADH) have demonstrated catalytic activity toward the asymmetric reduction of tert-butyl 6-chloro-3,5-dioxohexanoate (CDOH) to (S)-CHOH. Herein, a tetrad mutant of LkADH (LkTADH), A94T/F147L/L199H/A202L, was screened to be more efficient in this bioreduction process, exhibiting a 3.7- and 42-fold improvement in specific activity toward CDOH (1.27 U/mg) over LbADH (0.34 U/mg) and wild-type LkADH (0.03 U/mg), respectively. The molecular basis for the improved catalytic activity of LkTADH toward CDOH was investigated using homology modeling and docking analysis. Two major issues had a significant impact on the biocatalytic efficiency of this process, including (i) the poor aqueous stability of the substrate and (ii) partial substrate inhibition. A fed-batch strategy was successfully developed to address these issues and maintain a suitably low substrate concentration throughout the entire process. Several other parameters were also optimized, including the pH, temperature, NADP(+) concentration and cell loading. A final CDOH concentration of 427 mM (100 g/L) gave (S)-CHOH in 94 % yield and 99.5 % e.e. after a reaction time of 38 h with whole cells expressing LkTADH. The space-time yield and turnover number of NADP(+) in this process were 10.6 mmol/L/h and 16,060 mol/mol, respectively, which were the highest values ever reported. This new approach therefore represents a promising alternative for the efficient synthesis of (S)-CHOH.

  4. Free radicals in an Adamantane matrix. XI. Electron paramagnetic resonance study of conformations in the β-halo-tert-butyl radicals

    International Nuclear Information System (INIS)

    Lloyd, R.V.; Wood, D.E.

    1975-01-01

    The β-halo-tert-butyl radicals were prepared by x-irradiation of the corresponding isobutyl halides in an adamantane matrix at 77 0 K and their conformations were determined by analysis of their EPR spectra. The radicals are nonplanar at the radical site, the fluoro and chloro radicals trans eclipsed and the bromo and iodo radicals gauche staggered with respect to the relative orientation of the carbon halogen bond and the direction of the singly occupied orbital. Vibration-rotation motions about the favored conformation are much larger for the fluoro radical than for the others. The rate of interconversion of the inequivalent methylene protons is approximately 1.5 x 10 9 sec -1 for the bromo radical at 202 0 K while it is too slow to measure for the iodo radical at the same temperature. The barrier to interconversion has a lower limit of 3 kcal/mol for the bromo radical and higher than that for the iodo radical. The halogen and proton hfsc in gauss and the g values for the XCH 2 C(CH 3 ) 2 radicals are: 19 F = 103.7, CH 2 = 10.4, CH 3 = 23.3, g = 2.0030 at 214 K; 35 Cl = 19.5, CH 2 = 6.3, CH 3 = 21.1, g = 2.0042 at 215 K; 81 Br = 6.7, CH 2 = 21.4, 42.7, CH 3 = 21.4, g = 2.0010 at 202 K; 127 I = 7.0, CH 2 = 21.9, 43.8, CH 3 = 21.9, g = 2.0009 at 208 K. The fluoro radical decays to nonradical products above 318 0 K, the chloro radical converts to 2-methyl allyl radical above 306 0 K, the bromo radical converts to tert-butyl radical by exchange with a matrix proton (or deuteron) at 209 0 K as does the iodo radical above 225 0 K. Photolysis with a Xe lamp converts the bromo and iodo radicals to nonradical products in less than the experimental time constant of 0.3 sec. The hypothesis is put forward that the nonplanarity and high barrier to rotation observed explain the retention of stereochemical configuration in reactions involving β-chloro, β-bromo, and β-iodo alkyl radicals. (auth)

  5. Synthesis of [[sup 123]I]tert-Butyl 8-iodo-5,6-dihydro-5-methyl-6-oxo-4H-imidazo[1,5-a][1,4]benzodiaze pine 3-carboxylate, a potential SPECT imaging agent for diazepam-intensive (DI) benzodiazepine receptors

    Energy Technology Data Exchange (ETDEWEB)

    He, Xiaoshu; Matecka, Dorota; Gu, Ziqiang; Rice, K C; Costa, B.R. de [National Inst. of Diabetes and Digestive and Kidney Diseases, Bethesda, MD (United States); Lee, K S [National Inst. of Mental Health, Washington, DC (United States); Wong, Garry; Skolnick, Phil [National Inst. of Diabetes and Digestive and Kidney Diseases, Bethesda, MD (United States). Lab. of Neuroscience

    1994-01-01

    [[sup 123]I]tert-Butyl 8-iodo-5,6-dihydro-5-methyl-6-oxo-4H-imidazo [1,5-a] [1,4]benzodiazepine 3-carboxylate ([[sup 123]I]3), a high affinity and selective radioligand for the diazepam insensitive (DI) benzodiazepine receptor was synthesized in 2 steps from tert-butyl 8-bromo-5,6-dihydro-5-methyl-6-oxo-4H-imidazo[1,5-a][1,4]benzodiaz epine 3-carboxylate. (Author).

  6. Adiabatic compressibility of pseudo-binary aqueous solutions of tert-butyl alcohol and dimethylsulfoxide as a result of ultrasonic investigations

    International Nuclear Information System (INIS)

    Miecznik, Piotr; Kaczmarek, Milena

    2006-01-01

    The tert-butyl alcohol (TBA) and dimethyl sulfoxide (DMSO) are two small molecules geometrically very similar, but having different polar groups. Taking into account the intermolecular interactions in the TBA/H 2 O and DMSO/H 2 O systems, especially in the water-rich region of concentration, the ultrasonic speeds (high accuracy resonance method at the frequency 7.5 MHz) and densities in pseudo-binary mixtures of the system: (TBA + H 2 O + DMSO) with the ratio (TBA + DMSO)/H 2 O = 1/25 have been measured. From these data, various thermodynamical parameters such as adiabatic compressibility, molar volume, thermal expansivity, and the deviation from reference system have been calculated. In addition, the isobaric molar heat capacity to convert adiabatic compressibility to the isothermal one has been measured. All these parameters have been discussed to explain solute-solvent and solute-solute interactions, especially the effect of the complexation process between TBA and DMSO molecules. The composition dependence of these deviations functions was interpreted in the light of the mixing schemes in the aqueous solutions of TBA and DMSO

  7. Adiabatic compressibility of pseudo-binary aqueous solutions of tert-butyl alcohol and dimethylsulfoxide as a result of ultrasonic investigations

    Energy Technology Data Exchange (ETDEWEB)

    Miecznik, Piotr [Institute of Acoustics, Adam Mickiewicz University, Umultowska 85, PL-61-614 Poznan (Poland)]. E-mail: miecznik@main.amu.edu.pl; Kaczmarek, Milena [Institute of Acoustics, Adam Mickiewicz University, Umultowska 85, PL-61-614 Poznan (Poland)

    2006-11-15

    The tert-butyl alcohol (TBA) and dimethyl sulfoxide (DMSO) are two small molecules geometrically very similar, but having different polar groups. Taking into account the intermolecular interactions in the TBA/H{sub 2}O and DMSO/H{sub 2}O systems, especially in the water-rich region of concentration, the ultrasonic speeds (high accuracy resonance method at the frequency 7.5 MHz) and densities in pseudo-binary mixtures of the system: (TBA + H{sub 2}O + DMSO) with the ratio (TBA + DMSO)/H{sub 2}O = 1/25 have been measured. From these data, various thermodynamical parameters such as adiabatic compressibility, molar volume, thermal expansivity, and the deviation from reference system have been calculated. In addition, the isobaric molar heat capacity to convert adiabatic compressibility to the isothermal one has been measured. All these parameters have been discussed to explain solute-solvent and solute-solute interactions, especially the effect of the complexation process between TBA and DMSO molecules. The composition dependence of these deviations functions was interpreted in the light of the mixing schemes in the aqueous solutions of TBA and DMSO.

  8. Fluctuating micro-heterogeneity in water–tert-butyl alcohol mixtures and lambda-type divergence of the mean cluster size with phase transition-like multiple anomalies

    International Nuclear Information System (INIS)

    Banerjee, Saikat; Furtado, Jonathan; Bagchi, Biman

    2014-01-01

    Water–tert-butyl alcohol (TBA) binary mixture exhibits a large number of thermodynamic and dynamic anomalies. These anomalies are observed at surprisingly low TBA mole fraction, with x TBA ≈ 0.03–0.07. We demonstrate here that the origin of the anomalies lies in the local structural changes that occur due to self-aggregation of TBA molecules. We observe a percolation transition of the TBA molecules at x TBA ≈ 0.05. We note that “islands” of TBA clusters form even below this mole fraction, while a large spanning cluster emerges above that mole fraction. At this percolation threshold, we observe a lambda-type divergence in the fluctuation of the size of the largest TBA cluster, reminiscent of a critical point. Alongside, the structure of water is also perturbed, albeit weakly, by the aggregation of TBA molecules. There is a monotonic decrease in the tetrahedral order parameter of water, while the dipole moment correlation shows a weak nonlinearity. Interestingly, water molecules themselves exhibit a reverse percolation transition at higher TBA concentration, x TBA ≈ 0.45, where large spanning water clusters now break-up into small clusters. This is accompanied by significant divergence of the fluctuations in the size of largest water cluster. This second transition gives rise to another set of anomalies around. Both the percolation transitions can be regarded as manifestations of Janus effect at small molecular level

  9. 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.

  10. FT-IR, FT-Raman spectra, density functional computations of the vibrational spectra and molecular conformational analysis of 2,5-di-tert-butyl-hydroquinone

    Science.gov (United States)

    Subramanian, N.; Sundaraganesan, N.; Dereli, Ö.; Türkkan, E.

    2011-12-01

    The purpose of finding conformer among six different possible conformers of 2,5-di-tert-butyl-hydroquinone (DTBHQ), its equilibrium geometry and harmonic wavenumbers were calculated by the B3LYP/6-31G(d,p) method. The infrared and Raman spectra of DTBHQ were recorded in the region 400-4000 cm -1 and 50-3500 cm -1, respectively. In addition, the IR spectra in CCl 4 at various concentrations of DTBHQ are also recorded. The computed vibrational wavenumbers were compared with the IR and Raman experimental data. Computational calculations at B3LYP level with two different basis sets 6-31G(d,p) and 6-311++G(d,p) are also employed in the study of the possible conformer of DTBHQ. The complete assignments were performed on the basis of the potential energy distribution (PED) of the vibrational modes, calculated using VEDA 4 program. The general agreement between the observed and calculated frequencies was established.

  11. Equilibrium surface tension and the interaction energy of DMSO with tert-butyl alcohol or iso-amyl alcohol at various temperatures

    International Nuclear Information System (INIS)

    Bagheri, Ahmad; Moradian, Zohreh

    2014-01-01

    Highlights: • Surface tension of non-ideal binary systems of alcohol/DMSO determined. • The surface tension data of binary mixtures were correlated with five equations. • The interaction energy values were calculated by using LWW model. • The U 12 value shows different behavior for two systems with increasing temperature. - Abstract: Surface tension of binary mixtures of tert-butyl alcohol (TBA) and iso-amyl alcohol (IAA) with DMSO (dimethyl sulfoxide) were measured over the entire concentration range at pressure of 82.5 kPa at temperatures between (298.15 and 328.15) K. Correlating the surface tension and surface tension deviation of the above mentioned binary systems was performed with empirical and thermodynamic based models. The average relative error obtained from the comparison of experimental and calculated surface tension values for the two binary systems with five models at various temperatures is less than 2%. The effect of temperature on the interaction energy values in binary mixtures has been used to obtain information about solute structural effects on DMSO. Also, the experimental data were used to evaluate the nature and type of intermolecular interactions in binary mixtures

  12. 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.

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

    International Nuclear Information System (INIS)

    Cloud, Andrew N.; Abelson, John R.; Davis, Luke M.; Girolami, Gregory S.

    2014-01-01

    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) 2 ] 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

  14. Protective Effects of Black Rice Extracts on Oxidative Stress Induced by tert-Butyl Hydroperoxide in HepG2 Cells

    Science.gov (United States)

    Lee, Seon-Mi; Choi, Youngmin; Sung, Jeehye; Kim, Younghwa; Jeong, Heon-Sang; Lee, Junsoo

    2014-01-01

    Black rice contains many biologically active compounds. The aim of this study was to investigate the protective effects of black rice extracts (whole grain extract, WGE and rice bran extract, RBE) on tert-butyl hydroperoxide (TBHP)-induced oxidative injury in HepG2 cells. Cellular reactive oxygen species (ROS), antioxidant enzyme activities, malondialdehyde (MDA) and glutathione (GSH) concentrations were evaluated as biomarkers of cellular oxidative status. Cells pretreated with 50 and 100 μg/mL of WGE or RBE were more resistant to oxidative stress in a dose-dependent manner. The highest WGE and BRE concentrations enhanced GSH concentrations and modulated antioxidant enzyme activities (glutathione reductase, glutathione-S-transferase, catalase, and superoxide dismutase) compared to TBHP-treated cells. Cells treated with RBE showed higher protective effect compared to cells treated with WGE against oxidative insult. Black rice extracts attenuated oxidative insult by inhibiting cellular ROS and MDA increase and by modulating antioxidant enzyme activities in HepG2 cells. PMID:25580401

  15. Disposition of 2,6-di-tert-butyl-4-nitrophenol (DBNP), a submarine atmosphere contaminant, in male Sprague-Dawley rats

    International Nuclear Information System (INIS)

    Still, Kenneth R.; Jung, Anne E.; Ritchie, Glenn D.; Jederberg, Warren W.; Wilfong, Erin R.; Briggs, G. Bruce; Arfsten, Darryl P.

    2005-01-01

    The phenol 2,6-di-tert-butyl-4-nitrophenol (DBNP) is a contaminant found onboard submarines and is formed by the nitration of an antioxidant present in turbine lubricating oil TEP 2190. DBNP has been found on submarine interior surfaces, on eating utensils and dishes, and on the skin of submariners. DBNP exposure is a potential health concern because it is an uncoupler of mitochondrial oxidative phosphorylation. Adult male rats were dosed once by oral gavage with 15 or 40 mg/kg DBNP mixed with 14 C-DBNP in kanola oil and 0.8% v/v DMSO (n=16/group). The distribution of 14 C in major tissues was measured over time for up to 240 h post-dose. Unexpectedly, 6/16 (40%) of the rats gavaged with 40 mg/kg DBNP died within 24 h of dosing. Prostration, no auditory startle response, reduced locomotor activity, and muscular rigidity persisted in survivors for up to 8 days after dosing. For animals dosed with 15 mg/kg DBNP, radioactivity levels were significantly elevated in the following tissues 24 h after dosing: fat>>>liver>kidneys>heart>lungs>brain>striated muscle>spleen. Radioactivity levels were elevated for fat, liver, kidney, heart, and lungs of animals euthanized 144 h post-dosing and in the liver of animals euthanized 240 h post-dosing. These findings suggest that DBNP may accumulate in the body as a result of continuous or repeat exposures of short interval to DBNP

  16. The Synergistic Effects of Heat Shock Protein 70 and Ginsenoside Rg1 against Tert-Butyl Hydroperoxide Damage Model In Vitro

    Directory of Open Access Journals (Sweden)

    Dan Lu

    2015-01-01

    Full Text Available Neural stem cells (NSCs transplanted is one of the hottest research to treat Alzheimer’s disease (AD, but cholinergic neurons from stem cells were also susceptible to cell death which Heat shock protein 70 (HSP70 was affirmed to reverse. Related to cognitive impairment, cholinergic nervous cells should be investigated and ginsenoside Rg1 (G-Rg1 was considered to increase them. We chose tert-butyl hydroperoxide (t-BHP damage model to study in vitro. Functional properties of our recombination plasmid pEGFP-C2-HSP70 were affirmed by SH-SY5Y cells. To opposite the transitory appearance of HSP70, NSCs used as the vectors of HSP70 gene overexpressed HSP70 for at least 7 days in vitro. After transfection for 3 days, G-Rg1 pretreatment for 4 hours, and coculture for 3 days, the expression of acetylcholinesterase (ChAT, synaptophysin, and the ratio of NeuN and GFAP were assessed by western blot; Morphological properties were detected by 3D reconstruction and immunofluorescence. ChAT was markedly improved in the groups contained G-Rg1. In coculture system, the ratio of neurons/astrocytes and the filaments of neurons were increased; apoptosis cells were decreased, compared to monotherapy (P<0.05. In conclusion, we demonstrated that, as a safe cotreatment affirmed in vitro, overexpression of HSP70 in NSCs plus G-Rg1 promoted nervous cells regeneration from chronic oxidative damage.

  17. 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.

  18. Oxidation of Commercial Petronas Diesel with Tert-Butyl Hydroperoxide Over Poly molybdate Alumina Supported Catalyst Modified With Alkaline Earth Metals

    International Nuclear Information System (INIS)

    Wan Nazwanie Wan Abdullah; Rusmidah Ali; Wan Azlee Wan Abu Bakar

    2016-01-01

    Due to strict environmental legislation for ultra-low sulfur diesel fuels, increasing technical and operational challenges are imposed to conventional hydrodesulfurization (HDS) technology. Therefore, catalytic oxidative desulfurization (Cat-ODS) has been suggested to be an alternative method to replace a conventional method which is hydrodesulfurization. In this study, catalytic oxidation of commercial diesel was performed using an oil-soluble oxidant, tert-butyl hydroperoxide (TBHP), over poly molybdate supported on alumina MoO_3-PO_4/ Al_2O_3 catalyst. A commercial Petronas diesel with 440 ppm of total sulfur was employed to evaluate the elimination of sulfur compounds. Besides, the percentage of sulfur removal was measured by (GC-FPD). Alkaline earth metals, such as Calcium (Ca), Barium (Ba) and Strontium (Sr) were introduced on the surface of MoO_3-PO_4/ Al_2O_3. The results showed that the catalytic activity decreased in the order, Ca/ MoO_3-PO_4/ Al_2O_3>Sr/ MoO_3-PO_4/ Al_2O_3> Ba/ MoO_3-PO_4/ Al_2O_3. The Ca/ MoO_3-PO_4/ Al_2O_3 catalyst was characterized by XRD and FESEM. XRD results showed that the best catalyst was highly amorphous while FESEM micrograph illustrated an aggregation and agglomeration of various particle sizes. The catalytic activity of Ca/ MoO_3-PO_4/ Al_2O_3 catalyst with various Ca/ Mo ratios were also studied. When the Ca/ Mo ratio was 15:85, the sulfur removal was the highest (79 %) at 45 degree Celsius, 30 min and O/ S molar ratio 3.0 with solvent = dimethylformamide (DMF), diesel/ solvent ratio = 1.0. (author)

  19. Solution processable 2-(trityloxy)ethyl and tert-butyl group containing amorphous molecular glasses of pyranylidene derivatives with light-emitting and amplified spontaneous emission properties

    Science.gov (United States)

    Zarins, Elmars; Vembris, Aivars; Misina, Elina; Narels, Martins; Grzibovskis, Raitis; Kokars, Valdis

    2015-11-01

    Small organic molecules with incorporated 4H-pyran-4-ylidene (pyranylidene) fragment as the π-conjugation system which bonds the electron acceptor fragment (A) with electron donor part (D) in the molecule - also well known as derivatives of 4-(dicyano-methylene)-2-methyl-6-[p-(dimethylamino)styryl]-4H-pyran (DCM) laser dye-have attracted considerable attention of scientists as potential new generation materials for organic photonics and molecular electronics due to their low-cost fabrication possibility, flexibility and low-weight. Six glassy derivatives of 4H-pyran-4-ylidene (pyranylidene) with attached bulky 2-(trityloxy)ethyl and tert-butyl groups are described in this report. Almost all of the synthesized compounds form good optical quality transparent amorphous films from volatile organic solvents and could be obtained in good yields up to 75%. Their light emission in solution and thin solid films is in the range of 600-700 nm, they are thermally stable and show glass transition in the range of 108-158 °C. The amplified spontaneous emission threshold values of the neat films of the glassy pyranylidene derivatives vary from 155 to 450 μJ/cm2 and their HOMO and LUMO energy levels are between of those of tris(8-hydroxy quinolinato) aluminum (Alq3). The photoluminescence quantum yields of the glassy compounds are in the range from 1% to about 7.7% and their electroluminescence properties have been investigated. Therefore, glassy pyranylidene derivatives could be a very potential low-cost solution processable materials for Alq3 hosted light-amplification and light-emitting application studies.

  20. Solid binary mixtures of neopentanol with tert-Butyl chloride and carbon tetrachloride studied by thermal, X-ray and dielectric techniques

    Energy Technology Data Exchange (ETDEWEB)

    Chandra, Girish; Murthy, S.S.N., E-mail: ssnm0700@gmail.com

    2016-05-10

    Highlights: • DSC, dielectric and X-ray measurements have been done on TBC-NPOH and CTC-NPOH. • The results show the formation of solid solution for concentrations 0.7 ≤ x{sub m} ≤ 0.9. • A primary α-process and two sub-T{sub g} processes are found for TBC-NPOH. • For CTC-NPOH only one sub-T{sub g} process is found. • All the three sub-T{sub g} processes are Johari–Goldstein type. - Abstract: The binary mixtures of Neopentanol (NPOH) with tert-Butyl chloride (TBC) and Carbon tetrachloride (CTC), have been studied using Differential Scanning Calorimetry, Dielectric spectroscopy and X-ray diffraction techniques. The results indicate the formation of the solid solutions. The crystalline solid thus formed is found to be orientationally disordered and supercools easily to form glassy crystal for mole fraction of NPOH in the range of 0.7–0.9. The T{sub g} values are in the range of 140–147 K. In the dielectric study, a primary α-process and two sub-T{sub g} processes are found for TBC-NPOH, whereas for CTC-NPOH only one sub-T{sub g} process is found. The dielectric spectra of α- process follows the Havriliak–Negami equation. The sub-T{sub g} processes follow the Cole–Cole equation, and are found to be of Johari–Goldstein type, indicating intermolecular nature.

  1. Electronic structure and electron dynamics at an organic molecule/metal interface: interface states of tetra-tert-butyl-imine/Au(111)

    International Nuclear Information System (INIS)

    Hagen, Sebastian; Wolf, Martin; Tegeder, Petra; Luo Ying; Haag, Rainer

    2010-01-01

    Time- and angle-resolved two-photon photoemission (2PPE) spectroscopies have been used to investigated the electronic structure, electron dynamics and localization at the interface between tetra-tert-butyl imine (TBI) and Au(111). At a TBI coverage of one monolayer (ML), the two highest occupied molecular orbitals, HOMO and HOMO-1, are observed at an energy of -1.9 and -2.6 eV below the Fermi level (E F ), respectively, and coincide with the d-band features of the Au substrate. In the unoccupied electronic structure, the lowest unoccupied molecular orbital (LUMO) has been observed at 1.6 eV with respect to E F . In addition, two delocalized states that arise from the modified image potential at the TBI/metal interface have been identified. Their binding energies depend strongly on the adsorption structure of the TBI adlayer, which is coverage dependent in the submonolayer (≤1 ML) regime. Thus the binding energy of the lower interface state (IS) shifts from 3.5 eV at 1.0 ML to 4.0 eV at 0.5 ML, which is accompanied by a pronounced decrease in its lifetime from 100 fs to below 10 fs. This is a result of differences in the wave function overlap with electronic states of the Au(111) substrate at different binding energies. This study shows that in order to fully understand the electronic structure of organic adsorbates at metal surfaces, not only adsorbate- and substrate-induced electronic states have to be considered but also ISs, which are the result of a potential formed by the interaction between the adsorbate and the substrate.

  2. 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. © 2013 American Academy of Forensic Sciences.

  3. Isothermal Vapour-Liquid Equilibria in the Ternary System tert-Butyl Methyl Ether + tert-Butanol + 2,2,4-Trimethylpentane and the Three Binary Subsystems

    Czech Academy of Sciences Publication Activity Database

    Bernatová, Svatoslava; Wichterle, Ivan

    2001-01-01

    Roč. 180, 1-2 (2001), s. 235-245 ISSN 0378-3812 R&D Projects: GA ČR GA104/99/0136 Institutional research plan: CEZ:AV0Z4072921 Keywords : vapourůliquid equilibrium * experimental data * molar excess volume Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.217, year: 2001

  4. Radiation chemistry of alternative fuel oxygenates - substituted ethers

    International Nuclear Information System (INIS)

    Mezyk, S. P.; Cooper, W. J.; Bartels, D. M.; Tobien, T.; O'Shea, K. E.

    1999-01-01

    The electron beam process, an advanced oxidation and reduction technology, is based in the field of radiation chemistry. Fundamental to the development of treatment processes is an understanding of the underlying chemistry. The authors have previously evaluated the bimolecular rate constants for the reactions of methyl tert-butyl ether (MTBE) and with this study have extended their studies to include ethyl tert-butyl ether (ETBE), di-isopropyl ether (DIPE) and tert-amyl methyl ether (TAME) with the hydroxyl radical, hydrogen atom and solvated electron using pulse radiolysis. For all of the oxygenates the reaction with the hydroxyl radical appears to be of primary interest in the destruction of the compounds in water. The rates with the solvated electron are limiting values as the rates appear to be relatively low. The hydrogen atom rate constants are relatively low, coupled with the low yield in radiolysis, they concluded that these are of little significance in the destruction of the alternative fuel oxygenates (and MTBE)

  5. 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.

  6. 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.

  7. Determination of the extractive capacity of para-tert butyl calix[8]arene octa-phosphinoylated towards uranyl ions from an aqueous-acidic-salty medium

    International Nuclear Information System (INIS)

    Serrano V, E. C.

    2011-01-01

    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 3 -3.5 NaNO 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 -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 -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 2 ) 2 B 8 bL 8 (NO 3 ) 4 (H 2 O) 4 CHCl 3 (CH 3 OH) 3 the methanol molecules come from its purification. It is proposed that B 8 bL 8 calixarene in chloroform medium is a good extractant for the treatment of nuclear wastes or

  8. Linear free energy relationships in heterogeneous catalysis--13. The dehydration of aliphatic alcohols over silica-alumina. [N-butyl alcohol, sec. -butyl or isopropyl alcohol, tert. -butyl alcolol

    Energy Technology Data Exchange (ETDEWEB)

    Take, J; Matsumoto, T; Yoneda, Y

    1978-01-01

    The dehydration of n-butyl alcohol at 120/sup 0/-166/sup 0/C, sec.-butyl or isopropyl alcohol at 100/sup 0/-145/sup 0/C, and tert.-butyl alcohol at 54/sup 0/-80/sup 0/C, over silica/alumina catalyst was zero order in alcohol at 0.01-0.1 atm, and the activation energies were 35.3, 31.7, 32.0, and 29.9 kcal/mol, respectively. The zero-order rate constants were mainly affected by the activation energies since the preexponential factors varied little except for tert.-butyl alcohol. A linear relationship was found between the activation energy or the logarithm of the zero-order rate constant and the heterolytic bond dissociation energy for the carbon-oxygen bond in alcohols D(R/sup +/OH/sup -/). The activation energy increased and the rate constant decreased with increasing D(R/sup +/OH/sup -/). The results indicate that dehydration is E1 over this catalyst, but a similar correlation was observed based on published data for dehydration over alumina, which follows an E2 mechanism, indicating that heterolytic cleavage of the C-O bond is rate-determining in both mechanisms.

  9. Biodegradability of fuel-ethers in environment; Biodegradabilite des ethers-carburants dans l'environnement

    Energy Technology Data Exchange (ETDEWEB)

    Fayolle-Guichard, F

    2005-04-01

    Fuel ethers (methyl tert-butyl ether or MTBE, ethyl tert-butyl ether or ETBE and tert-amyl methyl ether or TAME have been used as gasoline additives since about twenty years in order to meet the requirements for the octane index and to limit the polluting emission in exhaust pipe gas (unburnt hydrocarbons and carbon monoxide). The high water solubility and the poor biodegradability of these compounds make them pollutants frequently encountered in aquifers. The present manuscript summarizes the knowledge concerning the biodegradability of fuel ethers obtained both at IFP and during collaborations with the Pasteur Institute (Paris), the Biotechnology Research Institute (Montreal, Canada) and the Center for Environmental Biotechnology (University of Tennessee, USA). Rhodococcus ruber IFP 2001 and Mycobacterium austroafricanum IFP 2012, two microorganisms isolated at IFP for their ability to grow, respectively, on ETBE and MTBE, were studied in order to determine the intermediates produced during MTBE and ETBE biodegradation and the enzymes required for each biodegradation step, thus allowing us to propose MTBE and ETBE catabolic pathways. A proteomic approach, from the protein induced during the degradation of ETBE or MTBE to the genes encoding these different enzymes, was carried out. The isolation of such genes is required:1) to use them for help in determining the bio-remediation capacities in polluted aquifers (DNA micro-arrays), 2) to monitor the microorganisms isolated for their degradative capacities during bio-remediation processes (fluorescent in situ hybridization or FISH) and 3) to create new tools for the detection and the quantification of ETBE or MTBE in contaminated aquifers (bio-sensor). The manuscript also describes the different ways for the adaptation of microorganisms to the presence of a xenobiotic compound. (author)

  10. 1,2'-Bis(4-aminophenoxy)benzene based designed fluoro-poly(ether-imide)/MMT clay nanocomposites: Synthesis and properties for high performance applications

    International Nuclear Information System (INIS)

    Vora, Rohitkumar H.; Vora, Mayur

    2006-01-01

    In an effort to develop structure-property understanding of fluoro-polymer/inorganic clay nanocomposite (i.e., Ceramer) technology, two series of fluoro-poly(ether amic acid) (6F-PEAA)/organosoluble Montmorillonite (MMT) clay nanocomposite formulations containing varying percentage of diamine modified (ion-exchanged) organosoluble-MMT clay were prepared from the partially fluorinated fluoro poly(ether-amic acid)s (6F-PEAA) synthesized by reacting on 2,2'-bis(3,4-dicarboxyphenyl) hexafluoropropane dianhydride (6FDA) and di-ether-containing diamines, such as 1,2'-bis(4-aminophenoxy) benzene (o-BAPOB) and 4,4'-bis(4-aminophenoxy) diphenyl sulfone (p-SED), respectively. Self supporting films were cast from these formulations and cured at elevated temperatures. XRD data, indirectly confirmed the exfoliation of organosoluble-MMT clay at molecular level in the nanocomposite. The solubility, chemical resistance, morphology, thermo-oxidative stability, thermal degradation kinetics, mechanical behavior, and moisture absorption of these [(6F-PEI)/MMT clay] nanocomposite films were systematically studied

  11. Thermally Activated Paramagnets from Diamagnetic Polymers of Biphenyl-3,5-diyl Bis(tert-butyl Nitroxides Carrying Methyl and Fluoro Groups at the 2’- and 5’-Positions

    Directory of Open Access Journals (Sweden)

    Toru Yoshitake

    2016-03-01

    Full Text Available Three new biradicals—2’,5’-dimethyl-, 2’-fluoro-5’-methyl-, and 5’-fluoro-2’-methyl- biphenyl-3,5-diyl bis(tert-butyl nitroxides—were synthesized. The magnetic susceptibility measurements revealed their diamagnetism below and around room temperature. The nitroxide groups are located close to each other in an intermolecular fashion to form a weakly covalent head-to-tail (NO2 ring. Biradical molecules are connected on both radical sites, constructing a diamagnetic chain. The dimethyl derivative underwent a structural phase transition at 83 °C, clarified via differential scanning calorimetry and powder X-ray diffraction, and a paramagnetic solid phase with S = 1 irreversibly appeared. The other analogues exhibited a similar irreversible upsurge of the magnetic susceptibility on heating, but the transition was characterized as the melting.

  12. 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

  13. Biodegradability of fuel-ethers in environment; Biodegradabilite des ethers-carburants dans l'environnement

    Energy Technology Data Exchange (ETDEWEB)

    Fayolle-Guichard, F.

    2005-04-01

    Fuel ethers (methyl tert-butyl ether or MTBE, ethyl tert-butyl ether or ETBE and tert-amyl methyl ether or TAME have been used as gasoline additives since about twenty years in order to meet the requirements for the octane index and to limit the polluting emission in exhaust pipe gas (unburnt hydrocarbons and carbon monoxide). The high water solubility and the poor biodegradability of these compounds make them pollutants frequently encountered in aquifers. The present manuscript summarizes the knowledge concerning the biodegradability of fuel ethers obtained both at IFP and during collaborations with the Pasteur Institute (Paris), the Biotechnology Research Institute (Montreal, Canada) and the Center for Environmental Biotechnology (University of Tennessee, USA). Rhodococcus ruber IFP 2001 and Mycobacterium austroafricanum IFP 2012, two microorganisms isolated at IFP for their ability to grow, respectively, on ETBE and MTBE, were studied in order to determine the intermediates produced during MTBE and ETBE biodegradation and the enzymes required for each biodegradation step, thus allowing us to propose MTBE and ETBE catabolic pathways. A proteomic approach, from the protein induced during the degradation of ETBE or MTBE to the genes encoding these different enzymes, was carried out. The isolation of such genes is required:1) to use them for help in determining the bio-remediation capacities in polluted aquifers (DNA micro-arrays), 2) to monitor the microorganisms isolated for their degradative capacities during bio-remediation processes (fluorescent in situ hybridization or FISH) and 3) to create new tools for the detection and the quantification of ETBE or MTBE in contaminated aquifers (bio-sensor). The manuscript also describes the different ways for the adaptation of microorganisms to the presence of a xenobiotic compound. (author)

  14. Glycerol etherification with TBA: high yield to poly-ethers using a membrane assisted batch reactor.

    Science.gov (United States)

    Cannilla, Catia; Bonura, Giuseppe; Frusteri, Leone; Frusteri, Francesco

    2014-05-20

    In this work, a novel approach to obtain high yield to poly-tert-butylglycerolethers by glycerol etherification reaction with tert-butyl alcohol (TBA) is proposed. The limit of this reaction is the production of poly-ethers, which inhibits the formation of poly-ethers potentially usable in the blend with conventional diesel for transportation. The results herein reported demonstrate that the use of a water permselective membrane offers the possibility to shift the equilibrium toward the formation of poly-ethers since the water formed during reaction is continuously and selectively removed from the reaction medium by the recirculation of the gas phase. Using a proper catalyst and optimizing the reaction conditions, in a single experiment, a total glycerol conversion can be reached with a yield to poly-ethers close to 70%, which represents data never before reached using TBA as reactant. The approach here proposed could open up new opportunities for all catalytic reactions affected by water formation.

  15. Selective liquid phase oxidation of benzyl alcohol to benzaldehyde by tert-butyl hydroperoxide over γ-Al{sub 2}O{sub 3} supported copper and gold nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Ndolomingo, Matumuene Joe; Meijboom, Reinout, E-mail: rmeijboom@uj.ac.za

    2017-03-15

    Highlights: • Cu and Au on γ-Al{sub 2}O{sub 3} catalysts were prepared and characterized. • Benzyl alcohol oxidation to benzaldehyde was performed by tert-butyl hydroperoxide in the absence of any solvent using the prepared catalysts. • The as prepared catalysts exhibited good performance in terms of conversion and selectivity towards benzaldehyde. • The kinetics of the reaction was investigated; k{sub app} was proportional to the amount of nano catalyst and oxidant present in the system. • The catalysts was recycled and reused with neither significant loss of activity nor selectivity. - Abstract: Benzyl alcohol oxidation to benzaldehyde was performed by tert-butyl hydroperoxide (TBHP) in the absence of any solvent using γ-Al{sub 2}O{sub 3} supported copper and gold nanoparticles. Li{sub 2}O 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), N{sub 2} 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

  16. Benzene and MTBE Sorption in Fine Grain Sediments

    Science.gov (United States)

    Leal-Bautista, R. M.; Lenczewski, M. E.

    2003-12-01

    The practice of adding methyl tert-butyl ether (MTBE) to gasoline started in the late 1970s and increased dramatically in the 1990s. MTBE first was added as a substitute for tetra-ethyl lead then later as a fuel oxygenate. Although the use of MTBE has resulted in significant reduction in air pollution, it has become a significant groundwater contaminant due to its high solubility in water, high environmental mobility, and low potential for biodegradation. A recent report (1999-2001) by the Metropolitan Water District of Southern California in collaboration with United State Geological Survey and the Oregon Health and Science University found that MTBE was the second most frequent detected volatile organic compound in groundwater. In Illinois, MTBE has been found in 26 of the 1,800 public water supplies. MTBE has also been blended in Mexico into two types of gasoline sold in the country by the state oil company (PEMEX) but is not monitored in groundwater at this time. Early research on MTBE considered it unable to adsorb to soils and sediments, however, by increasing the organic matter and decreasing the size of the grains (silts or clays) this may increase sorption. The objective of this study is to determine if fine grained materials have the potential for sorption of MTBE due to its high specific surface area (10-700 m 2/g) and potentially high organic matter (0.5-3.8%). The experiment consisted of sorption isotherms to glacial tills from DeKalb, Illinois and lacustrine clays from Chalco, Mexico. Experiments were performed with various concentrations of MTBE and benzene (10, 50, 100, 500 and 1000 ug/L) at 10° C and 25° C. Results showed a range of values for the distribution coefficient (Kd, linear model). At 10° C the Kd value for MTBE was 0.187 mL/g for lacustrine clay while the glacial loess had a value of 0.009 mL/g. The highest Kd values with MTBE were 0.2859 mL/g for organic rich lacustrine clays and 0.014 mL/g for glacial loess at 25° C. The highest

  17. Vibrational spectra and ab initio analysis of tert-butyl, trimethylsilyl, and trimethylgermyl derivatives of 3,3-dimethylcyclopropene II. 3,3-Dimethyl-1,2-bis(trimethylsilyl)cyclopropene

    Science.gov (United States)

    Panchenko, Yu. N.; De Maré, G. R.; Abramenkov, A. V.; Baird, M. S.; Tverezovsky, V. V.; Nizovtsev, A. V.; Bolesov, I. G.

    2003-07-01

    The IR and Raman spectra of 3,3-dimethyl-1,2-bis(trimethylsilyl)cyclopropene (I) (synthesised using standard procedures) were measured in the liquid phase. Total geometry optimisation was performed at the HF/6-31G* level. The HF/6-31G*//HF/6-31G* quantum mechanical force field (QMFF) was calculated and used to determine the theoretical fundamental vibrational frequencies, their predicted IR intensities, Raman activities, and Raman depolarisation ratios. Using Pulay's scaling method and the theoretical molecular geometry, the QMFF of I was scaled by a set of scaling factors used previously for 3,3-dimethyl-1,2-bis(tert-butyl)cyclopropene (17 scale factors for a 105-dimensional problem). The scaled QMFF obtained was used to solve the vibrational problem. The quantum mechanical values of the Raman activities were converted to differential Raman cross sections. The figures for the experimental and theoretical Raman and IR spectra are presented. Assignments of the experimental vibrational spectra of I are given. They take into account the calculated potential energy distribution and the correlation between the estimations of the experimental IR and Raman intensities and Raman depolarisation ratios and the corresponding theoretical values (including Raman cross sections) calculated using the unscaled QMFF.

  18. Effects of intraperitoneal administration of the GABAB receptor positive allosteric modulator 2,6-di tert-butyl-4-(2-hydroxy-2,2-dimethyl-propyl)-phenol (CGP7930) on food intake in non-deprived rats.

    Science.gov (United States)

    Ebenezer, Ivor S

    2012-09-05

    γ-Aminobutyric acid-(B) (GABA(B)) receptor positive allosteric modulators (PAMs) act on an allosteric site on the GABA(B) receptor to potentiate the effects of GABA and GABA(B) receptor agonists. It has previously been demonstrated that the GABA(B) receptor agonist baclofen increases food intake in non-deprived rats. The aim of this study was to investigate whether the GABA(B) receptor PAM 2,6-di tert-butyl-4-(2-hydroxy-2,2-dimethyl-propyl)-phenol (CGP7930) would (i) increase food intake, and (ii) potentiate the hyperphagic effects of baclofen in rats. In Experiment 1, the effects of intraperitoneal (i.p.) administration of CGP7930 (1, 6 and 12 mg/kg) was investigated on food intake in non-deprived male Wistar rats. The 12 mg/kg dose of CGP7930 significantly increased cumulative food intake 30, 60 and 120 min (PGABA and GABA(B) receptor agonists by allosteric modulation of the GABA(B) receptor. Copyright © 2012 Elsevier B.V. All rights reserved.

  19. μ-Carbonato-κ(4) O,O':O',O''-bis-{[2'-(di-tert-butyl-phosphan-yl)biphenyl-2-yl-κ(2) P,C (1)]palladium(II)} dichloro-methane monosolvate.

    Science.gov (United States)

    Muller, Alfred; Holzapfel, Cedric W

    2012-12-01

    The title compound, [(μ2-CO3){Pd(P(t-C4H9)2(C12H8)}2]·CH2Cl2, the first CO3-bridged palladium dimer complex reported to date, was obtained while preparing the Pd(0) complex with (2-biphen-yl)P( (t) Bu)2. In the crystal, each palladium dimer is accompanied by a dichloro-methane solvent mol-ecule. Coordination of the carbonate and chelated phosphane ligands gives distorted square-planar environments at the Pd atoms. Important geometrical parameters include Pd-P(av.) = 2.2135 (4) Å, Pd-C(av.) = 1.9648 (16) Å and P-Pd-C = 84.05 (5) and 87.98 (5)°, and O-Pd-O' = 60.56 (4) and 61.13 (4)°. Bonding with the carbonate O atoms shows values of 2.1616 (11) and 2.1452 (11) Å for the Pd-O-Pd bridge, whereas other Pd-O distances are slightly longer at 2.2136 (11) and 2.1946 (11) Å. One of the tert-butyl groups is disordered over two set of sites with an occupancy ratio of 0.723 (6):0.277 (6). Weak C-H⋯O interactions are observed propagating the molecules along the [100] direction.

  20. 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.

  1. FT-IR and Raman vibrational analysis, B3LYP and M06-2X simulations of 4-bromomethyl-6-tert-butyl-2H-chromen-2-one

    Science.gov (United States)

    Sert, Yusuf; Puttaraju, K. B.; Keskinoğlu, Sema; Shivashankar, K.; Ucun, Fatih

    2015-01-01

    In this study, the experimental and theoretical vibrational frequencies of a newly synthesized bacteriostatic and anti-tumor molecule namely, 4-bromomethyl-6-tert-butyl-2H-chromen-2-one have been investigated. The experimental FT-IR (4000-400 cm-1) and Raman spectra (4000-100 cm-1) of the compound in solid phase have been recorded. The theoretical vibrational frequencies and optimized geometric parameters have been calculated using density functional theory (DFT/B3LYP: Becke, 3-parameter, Lee-Yang-Parr and DFT/M06-2X: highly parametrized, empirical exchange correlation function) with 6-311++G(d, p) basis set by Gaussian 03 software, for the first time. The assignments of the vibrational frequencies have been done by potential energy distribution (PED) analysis using VEDA 4 software. The theoretical optimized geometric parameters and vibrational frequencies have been found to be in good agreement with the corresponding experimental data and results in the literature. In addition, the highest occupied molecular orbital (HOMO) energy, the lowest unoccupied molecular orbital (LUMO) energy and the other related molecular energy values of the compound have been investigated using the same theoretical calculations.

  2. Synthesis, spectroscopy, magnetic and redox behaviors of copper(II) complexes with tert-butylated salen type ligands bearing bis(4-aminophenyl)ethane and bis(4-aminophenyl)amide backbones.

    Science.gov (United States)

    Kasumov, Veli T; Yerli, Yusuf; Kutluay, Aysegul; Aslanoglu, Mehmet

    2013-03-01

    New salen type ligands, N,N'-bis(X-3-tert-butylsalicylidene)-4,4'-ethylenedianiline [(X=H (1), 5-tert-butyl (2)] and N,N'-bis(X-3-tert-butylsalicylidene)-4,4'-amidedianiline [X=H (3), 5-tert (4)] and their copper(II) complexes 5-8, have been synthesized. Their spectroscopic (IR, (1)H NMR, UV/vis, ESR) properties, as well as magnetic and redox-reactivity behavior are reported. IR spectra of 7 and 8 indicate the coordination of amide oxygen atoms of 3 and 4 ligands to Cu(II). The solid state ESR spectra of 5-8 exhibits less informative exchange narrowed isotropic or anisotropic signals with weak unresolved low field patterns. The magnetic moments of 5 (2.92 μ(B) per Cu(II)) and 6 (2.79 μ(B) per Cu(II)) are unusual for copper(II) complexes and considerably higher than those for complexes 7 and 8. Cryogenic measurements (300-10 K) show weak antiferromagnetic exchange interactions between the copper(II) centers in complexes 6 and 8. The results of electrochemical and chemical redox-reactivity studies are discussed. Copyright © 2012 Elsevier B.V. All rights reserved.

  3. 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.

  4. Excess enthalpies of ternary mixtures of (oxygenated additives + aromatic hydrocarbon) mixtures in fuels and bio-fuels: (Dibutyl-ether + 1-propanol + benzene), or toluene, at T = (298.15 and 313.15) K

    International Nuclear Information System (INIS)

    Alaoui, Fatima E.M.; Aguilar, Fernando; González-Fernández, María Jesús; Dakkach, Mohamed; Montero, Eduardo A.

    2015-01-01

    Highlights: • New excess enthalpy data for ternary mixtures of (dibutyl ether + aromatic hydrocarbon + 1-propanol) are reported. • 2 ternary systems at T = (298.15 and 313.15) K were measured by means of an isothermal flow calorimeter. • 230 data were fitted to a Redlich–Kister rational equation. • Intermolecular and association effects involved in these systems have been discussed. - Abstract: New experimental excess molar enthalpy data of the ternary systems (dibutyl ether + 1-propanol + benzene, or toluene), and the corresponding binary systems at T = (298.15 and 313.15) K at atmospheric pressure are reported. A quasi-isothermal flow calorimeter has been used to make the measurements. All the binary and ternary systems show endothermic character at both temperatures. The experimental data for the systems have been fitted using the Redlich–Kister rational equation. Considerations with respect the intermolecular interactions amongst ether, alcohol and hydrocarbon compounds are presented

  5. Vibrational spectra and ab initio analysis of tert-butyl, trimethylsilyl, and trimethylgermyl derivatives of 3,3-dimethylcyclopropene IV. 3,3-Dimethyl-1,2-bis(trimethylgermyl)cyclopropene

    Science.gov (United States)

    Panchenko, Yu. N.; De Maré, G. R.; Abramenkov, A. V.; Baird, M. S.; Tverezovsky, V. V.; Nizovtsev, A. V.; Bolesov, I. G.

    2003-06-01

    The infrared (IR) and Raman spectra of 3,3-dimethyl-1,2-bis(trimethylgermyl)cyclopropene (I) were measured in the liquid phase. Total geometry optimisation was performed at the HF/6-31G* level. The HF/6-31G*//HF6-31G* quantum mechanical force field (QMFF) was calculated and used to determine the theoretical fundamental vibrational frequencies, their predicted IR intensities, Raman activities, and Raman depolarisation ratios. Using Pulay's scaling method and the theoretical molecular geometry, the QMFF of I was scaled by a set of scaling factors comprised of elements transferred from the sets used to correct the QMFF's of 3,3-dimethylbutene-1, and 1-methyl-, 1,2-dimethyl-, and 3,3-dimethylcyclopropene (17 scale factors for a 105-dimensional problem). This set of scale factors was used previously to correct the QMFF of 3,3-dimethyl-1,2-bis(tert-butyl)cyclopropene and 3,3-dimethyl-1,2-bis(trimethylsilyl)cyclopropene. The scaled QMFF obtained was used to solve the vibrational problem. Differential Raman cross-sections were calculated using the quantum mechanical values of the Raman activities. The appropriate theoretical spectrograms for the Raman and IR spectra of I were constructed. Assignments of the experimental vibrational spectra of I are given. They take into account the calculated potential energy distributions and the correlation between the estimations of the experimental IR and Raman intensities and Raman depolarisation ratios and the corresponding theoretical values calculated using the unscaled QMFF.

  6. In vitro and in vivo effect of 2,6-Di-tert-butyl-4-methylphenol as an antibiofilm agent against quorum sensing mediated biofilm formation of Vibrio spp.

    Science.gov (United States)

    Santhakumari, Sivasubramanian; Jayakumar, Rengarajan; Logalakshmi, Ravichandran; Prabhu, Narayanan Marimuthu; Abdul Nazar, Abdul Kuthus; Karutha Pandian, Shunmugiah; Veera Ravi, Arumugam

    2018-05-25

    This study unveils the in vitro and in vivo antibiofilm potential of 2,6-Di-tert-butyl-4-methylphenol (DTBMP) from Chroococcus turgidus against Vibrio spp. In the preliminary study, cell free culture supernatant (CFCS) of C. turgidus inhibited the violacein production in biomarker strain Chromobacterium violaceum and its mutant strain CV026 in a dose dependent manner. The effective biofilm inhibitory concentration (BIC) of pure compound DTBMP from C. turgidus was identified as 250 μg/ml concentration in tested Vibrio species. Furthermore, DTBMP proved to effectively inhibit the bioluminescence production in V. harveyi and other biofilm related virulence traits such as exopolysaccharides (EPS) production, hydrophobicity index, swimming and swarming motility at its BIC concentration in three major pathogenic vibrios: V. harveyi, V. parahaemolyticus and V. vulnificus. The antibiofilm potential of DTBMP was validated through light, confocal laser scanning and scanning electron microscopic analyses. In addition, the non-bactericidal effect of DTBMP was determined through growth curve and 2,3-bis (2-methyloxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide (XTT) assay. Real-time PCR studies revealed the down-regulation of master quorum sensing (QS) regulator genes of V. harveyi such as luxR, luxS, luxP, luxQ and luxO on treatment with DTBMP. In vivo results confirmed that DTBMP augmented the survival rate of Litopenaeus vannamei larvae up to 75, 88 and 66% upon infection with V. harveyi, V. parahaemolyticus and V. vulnificus, respectively. The results of this study ascertain the promising effects of DTBMP as an antibiofilm agent, which could be positively explored to treat biofilm-associated vibrios infections in aquaculture. Copyright © 2018 Elsevier B.V. All rights reserved.

  7. 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.

  8. 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

    Czech Academy of Sciences Publication Activity Database

    Morávková, Lenka; Wagner, Zdeněk; Sedláková, Zuzana; Linek, Jan

    2010-01-01

    Roč. 42, č. 7 (2010), s. 920-925 ISSN 0021-9614 R&D Projects: GA ČR GA104/09/0666 Institutional research plan: CEZ:AV0Z40720504 Keywords : isooctane * ternary mixture * adiabatic compressibility Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.794, year: 2010

  9. Modeling the competitive effect of ammonium oxidizers and heterotrophs on the degradation of MTBE in a packed bed reactor

    DEFF Research Database (Denmark)

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

    2008-01-01

    A mathematical model was used to study effects on the degradation of methyl tert-butyl ether (MTBE) in a packed bed reactor due to the presence of contaminants such as ammonium, and the mix of benzene, toluene, ethylbenzene and xylenes (BTEX). It was shown that competition between the slower...

  10. EFFECT OF BTEX ON THE DEGRADATION OF MTBE AND TBA BY MIXED BACTERIAL CONSORTIUM

    Science.gov (United States)

    Methyl tert-butyl ether (MTBE) contamination in groundwater often coexists with benzene, toluene, ethylbenzene, and xylene (BTEX) near the source of the plume. Tertiary butyl alcohol (TBA) is a prevalent intermediate of MTBE degradation. Therefore, there is a significant p...

  11. An improved synthesis process of calixcrown ethers and synthesis of novel calixcrown ether

    International Nuclear Information System (INIS)

    Wang Hairong; Zhang Ping; Wang Chunmiao; Wang Jianchen; Chen Jing

    2007-01-01

    The synthesis method of calixcrown ethers was simplified and improved, and 10 L- scale synthesis was carried out. In the synthesis of the intermediates of the first three steps, the synthesis of 5, 11, 17, 23-tetra-tert-butyl-25, 26, 27, 28-tetrahydroxyl-calix[4] and its dehydroxylation were considered together, the purification procedures of the former, including re-crystallization in toluene and decolorization with activated carbon, were cancelled, and thus these steps were simplified. In the synthesis of oligoethylene glycol ditosylate, the purification method was also improved and the time-consuming column chromatography was left out. In the final step, impurities were removed by repeating stirring-settlement steps, by following recrystallization, the pure product was obtained. With these measures, the whole process could be implemented easily. The industrial scale production of calixcrown ethers could be fulfilled with the improved process. In addition, a new extracant, 25, 27-bis (n-propyloxy)calix[4]-26, 28-crown-6, is prepared and identified. (authors)

  12. Solvent extraction of Ca2+, Ba2+, Cu2+, Zn2+, Cd2+, Pb2+, UO22+, Mn2+, Co2+ and Ni2+ into nitrobenzene using strontium dicarbol-lylcobaltate and tetra-tert-butyl p-tert-butylcalix[4]arene tetraacetate

    Directory of Open Access Journals (Sweden)

    E. MAKRLÍK

    2008-12-01

    Full Text Available The exchange extraction constants corresponding to the general equilibrium M2+(aq + SrL2+(nb D ML2+ (nb + Sr2+ (aq occurring in the two-phase water–nitrobenzene system (M2+ = Ca2+, Ba2+, Cu2+, Zn2+, Cd2+, Pb2+, UO22+, Mn2+, Co2+ or Ni2+; L = tetra-tert-butyl p-tert-butylcalix[4]arene tetraacetate; aq = aqueous phase; nb = nitrobenzene phase were evaluated from extraction experiments and -activity measurements. Furthermore, the stability constants of the ML2+ complexes in water saturated nitrobenzene were calculated; they were found to increase in the cation order Ba2+ < Mn2+ < Pb2+, Co2+ < Cu2+, Zn2+ < Cd2+, Ni2+ < UO22+ < Ca2+.

  13. Analysis of dissolved benzene plumes and methyl tertiary butyl ether (MTBE) plumes in ground water at leaking underground fuel tank (LUFT) sites

    International Nuclear Information System (INIS)

    Happel, A.M.; Rice, D.; Beckenbach, E.; Savalin, L.; Temko, H.; Rempel, R.; Dooher, B.

    1996-11-01

    The 1990 Clean Air Act Amendments mandate the addition of oxygenates to gasoline products to abate air pollution. Currently, many areas of the country utilize oxygenated or reformulated fuel containing 15- percent and I I-percent MTBE by volume, respectively. This increased use of MTBE in gasoline products has resulted in accidental point source releases of MTBE containing gasoline products to ground water. Recent studies have shown MTBE to be frequently detected in samples of shallow ground water from urban areas throughout the United States (Squillace et al., 1995). Knowledge of the subsurface fate and transport of MTBE in ground water at leaking underground fuel tank (LUFT) sites and the spatial extent of MTBE plumes is needed to address these releases. The goal of this research is to utilize data from a large number of LUFT sites to gain insights into the fate, transport, and spatial extent of MTBE plumes. Specific goals include defining the spatial configuration of dissolved MTBE plumes, evaluating plume stability or degradation over time, evaluating the impact of point source releases of MTBE to ground water, and attempting to identify the controlling factors influencing the magnitude and extent of the MTBE plumes. We are examining the relationships between dissolved TPH, BTEX, and MTBE plumes at LUFT sites using parallel approaches of best professional judgment and a computer-aided plume model fitting procedure to determine plume parameters. Here we present our initial results comparing dissolved benzene and MTBE plumes lengths, the statistical significance of these results, and configuration of benzene and MTBE plumes at individual LUFT sites

  14. Crystal structure of 4-tert-butyl-2-{2-[N-(3,3-dimethyl-2-oxobutyl-N-isopropylcarbamoyl]phenyl}-1-isopropyl-1H-imidazol-3-ium perchlorate

    Directory of Open Access Journals (Sweden)

    Olga V. Hordiyenko

    2015-02-01

    Full Text Available In the title salt, C26H40N3O2+·ClO4−, the positive charge of the organic cation is delocalized between the two N atoms of the imidazole ring. The C...;N bond distances are 1.338 (2 and 1.327 (3 Å. The substituents on the benzene ring are rotated almost orthogonal with respect to this ring due to the presence of the bulky isopropyl substituents. The dihedral angle between the benzene and imidazole rings is 75.15 (12°. Three of the O atoms of the anion are disordered over two sets of sites due to rotation around one of the O—Cl bonds. The ratio of the refined occupancies is 0.591 (14:0.409 (14. In the crystal, the cation and perchlorate anion are bound by an N—H...O hydrogen bond. In addition, the cation–anion pairs are linked into layers parallel to (001 by multiple weak C—H...O hydrogen bonds.

  15. Enterovirus inhibitory activity of C-8-tert-butyl substituted 4-aryl-6,7,8,9-tetrahydrobenzo[4,5]thieno[3,2-e][1,2,4]triazolo[4,3-a]pyrimidin-5(4H)-ones.

    Science.gov (United States)

    Kumar Biswas, Bishyajit; Malpani, Yashwardhan R; Ha, Neul; Kwon, Do-Hyun; Soo Shin, Jin; Kim, Hae-Soo; Kim, Chonsaeng; Bong Han, Soo; Lee, Chong-Kyo; Jung, Young-Sik

    2017-08-01

    Members of a series of 4-aryl-6,7,8,9-tetrahydrobenzo[4,5]thieno[3,2-e][1,2,4]triazolo[4,3-a]pyrimidin-5(4H)-ones (1, Fig. 2) were prepared and tested against representative enteroviruses including Human Coxsackievirus B1 (Cox B1), Human Coxsackievirus B3 (Cox B3), human Poliovirus 3 (PV3), human Rhinovirus 14 (HRV14), human Rhinovirus 21 (HRV 21) and human Rhinovirus 71 (HRV 71). The C-8-tert-butyl group on the tetrahydrobenzene ring in these substances was found to be crucial for their enterovirus activity. One member of this group, 1e, showed single digit micromolar activities (1.6-8.85μM) against a spectrum of viruses screened, and the highest selectivity index (SI) values for Cox B1 (>11.2), for Cox B3 (>11.5), and for PV3 (>51.2), respectively. In contrast, 1p, was the most active analog against the selected HRVs (1.8-2.6μM), and showed the highest selectivity indices among the group of compounds tested. The SI values for 1p were 11.5 for HRV14, 8.4 for HRV21, and 12.1 for HRV71, respectively. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Antioxidant action of 3-mercapto-5H-1,2,4-triazino[5,6-b]indole-5-acetic acid, an efficient aldose reductase inhibitor, in a 1,1'-diphenyl-2-picrylhydrazyl assay and in the cellular system of isolated erythrocytes exposed to tert-butyl hydroperoxide.

    Science.gov (United States)

    Prnova, Marta Soltesova; Ballekova, Jana; Majekova, Magdalena; Stefek, Milan

    2015-01-01

    The subject of this study was 3-mercapto-5H-1,2,4-triazino[5,6-b]indole-5-acetic acid (compound 1), an efficient aldose reductase inhibitor of high selectivity. The antioxidant action of 1 was investigated in greater detail by employing a 1,1'-diphenyl-2-picrylhydrazyl (DPPH) test and in the system of isolated rat erythrocytes. First, the compound was subjected to the DPPH test. Second, the overall antioxidant action of the compound was studied in the cellular system of isolated rat erythrocytes oxidatively stressed by free radicals derived from the lipophilic tert-butyl hydroperoxide. The uptake kinetics of 1 was studied and osmotic fragility of the erythrocytes was evaluated. The DPPH test revealed significant antiradical activity of 1. One molecule of 1 was found to quench 1.48 ± 0.06 DPPH radicals. In the system of isolated erythrocytes, the compound was readily taken up by the cells followed by their protection against free radical-initiated hemolysis. Osmotic fragility of the erythrocytes was not affected by 1. The results demonstrated the ability of 1 to scavenge DPPH and to protect intact erythrocytes against oxidative damage induced by peroxyl radicals. By affecting both the polyol pathway and oxidative stress, the compound represents an example of a promising agent for multi-target pharmacology of diabetic complications.

  17. 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.

  18. Landfills as sources of polyfluorinated compounds, polybrominated diphenyl ethers and musk fragrances to ambient air

    Science.gov (United States)

    Weinberg, Ingo; Dreyer, Annekatrin; Ebinghaus, Ralf

    2011-02-01

    In order to investigate landfills as sources of polyfluorinated compounds (PFCs), polybrominated diphenyl ethers (PBDEs) and synthetic musk fragrances to the atmosphere, air samples were simultaneously taken at two landfills (one active and one closed) and two reference sites using high volume air samplers. Contaminants were accumulated on glass fiber filters (particle phase) and PUF/XAD-2/PUF cartridges (gas phase), extracted by methyl-tert butyl ether/acetone (neutral PFCs), methanol (ionic PFCs) or hexane/acetone (PBDEs, musk fragrances), and detected by GC-MS (neutral PFCs, PBDEs, musk fragrances) or HPLC-MS/MS (ionic PFCs). Total concentrations ranged from 84 to 706 pg m -3 (volatile PFCs, gas phase), from fragrances, gas + particle phase) and from 1 to 11 pg m -3 (PBDEs, gas + particle phase). Observed sum concentrations of PFCs and synthetic musk fragrances and partly PBDE concentrations were elevated at landfill sites compared to corresponding reference sites. Concentrations determined at the active landfill were higher than those of the inactive landfill. Overall, landfills can be regarded as a source of synthetic musk fragrances, several PFCs and potentially of PBDEs to ambient air.

  19. Benzene poisoning

    Science.gov (United States)

    ... may be admitted to the hospital if the poisoning is severe. ... benzene they swallowed and how quickly they receive treatment. The ... Poisoning can cause rapid death. However, deaths have occurred ...

  20. μ-Carbonato-κ4 O,O′:O′,O′′-bis­{[2′-(di-tert-butyl­phosphan­yl)biphenyl-2-yl-κ2 P,C 1]palladium(II)} dichloro­methane monosolvate

    Science.gov (United States)

    Muller, Alfred; Holzapfel, Cedric W.

    2012-01-01

    The title compound, [(μ2-CO3){Pd(P(t-C4H9)2(C12H8)}2]·CH2Cl2, the first CO3-bridged palladium dimer complex reported to date, was obtained while preparing the Pd0 complex with (2-biphen­yl)P(tBu)2. In the crystal, each palladium dimer is accompanied by a dichloro­methane solvent mol­ecule. Coordination of the carbonate and chelated phosphane ligands gives distorted square-planar environments at the Pd atoms. Important geometrical parameters include Pd—P(av.) = 2.2135 (4) Å, Pd—C(av.) = 1.9648 (16) Å and P—Pd—C = 84.05 (5) and 87.98 (5)°, and O—Pd—O′ = 60.56 (4) and 61.13 (4)°. Bonding with the carbonate O atoms shows values of 2.1616 (11) and 2.1452 (11) Å for the Pd—O—Pd bridge, whereas other Pd—O distances are slightly longer at 2.2136 (11) and 2.1946 (11) Å. One of the tert-butyl groups is disordered over two set of sites with an occupancy ratio of 0.723 (6):0.277 (6). Weak C—H⋯O interactions are observed propagating the molecules along the [100] direction. PMID:23468771

  1. An octanuclear molybdenum(VI) complex containing coordinatively bound 4,4'-di-tert-butyl-2,2'-bipyridine, [Mo8O22(OH)4(di-tBu-bipy)4]: synthesis, structure, and catalytic epoxidation of bio-derived olefins.

    Science.gov (United States)

    Amarante, Tatiana R; Neves, Patrícia; Tomé, Cátia; Abrantes, Marta; Valente, Anabela A; Paz, Filipe A Almeida; Pillinger, Martyn; Gonçalves, Isabel S

    2012-03-19

    The reaction of [MoO(2)Cl(2)(di-tBu-bipy)] (1) (di-tBu-bipy = 4,4'-di-tert-butyl-2,2'-bipyridine) with water at 100-120 °C in a Teflon-lined stainless steel autoclave, in an open reflux system, or in a microwave synthesis system gave the octanuclear complex [Mo(8)O(22)(OH)(4)(di-tBu-bipy)(4)] (2) as a microcrystalline powder in good yields. Single crystals of 2 suitable for X-ray diffraction were obtained by the reaction of MoO(3) and di-tBu-bipy in water at 160 °C for 3 days. The molecular structure of 2 comprises a purely inorganic core, Mo(4)O(8)(μ(3)-OH)(2)(μ(2)-O)(2), attached to two peripheral oxo-bridged binuclear units, Mo(2)O(4)(μ(2)-O)(2)(OH)(di-tBu-bipy)(2). The inorganic core is composed of a unique assembly of four {MoO(5)} distorted square pyramids connected to each other via edge-sharing. Overall, the octanuclear complex adopts a highly distorted form strongly resembling an "S"-shaped molecular unit. Complex 2 was applied in the catalytic epoxidation of the biorenewable olefins DL-limonene (Lim) and methyl oleate (Ole), using tert-butylhydroperoxide (TBHP) as an oxygen donor, under mild reaction conditions (55 °C, air). The reactions of Lim and Ole gave the respective epoxide monomers in fairly high selectivities at high conversions (89% 1,2-epoxy-p-menth-8-ene selectivity at 96% Lim conversion; 99% methyl 9,10-epoxystearate selectivity at 94% Ole conversion, reached within 24 h reaction). Iodometric titrations revealed no measurable "non-productive" decomposition of TBHP. © 2012 American Chemical Society

  2. Synthesis of highly reactive polyisobutylene catalyzed by EtAlCl 2/Bis(2-chloroethyl) ether soluble complex in hexanes

    KAUST Repository

    Kumar, Rajeev Ananda; Zheng, Bin; Huang, Kuo-Wei; Emert, Jack I.; Faust, Rudolf

    2014-01-01

    The polymerization of isobutylene (IB) to yield highly reactive polyisobutylene (HR PIB) with high exo-olefin content using GaCl3 or FeCl3·diisopropyl ether complexes has been previously reported.1 In an effort to further improve polymerization rates and exo-olefin content, we have studied ethylaluminum dichloride (EADC) complexes with diisopropyl ether, 2-chloroethyl ethyl ether (CEEE), and bis(2-chloroethyl) ether (CEE) as catalysts in conjunction with tert-butyl chloride as initiator in hexanes at different temperatures. All three complexes were readily soluble in hexanes. Polymerization, however, was only observed with CEE. At 0 °C polymerization was complete in 5 min at [t-BuCl] = [EADC·CEE] = 10 mM and resulted in PIB with ∼70% exo-olefin content. Studies on complexation using ATR FTIR and 1H NMR spectroscopy revealed that at 1:1 stoichiometry a small amount of EADC remains uncomplexed. By employing an excess of CEE, exo-olefin contents increased up to 90%, while polymerization rates decreased only slightly. With decreasing temperature, polymerization rates decreased while molecular weights as well as exo-olefin contents increased, suggesting that isomerization has a higher activation energy than β-proton abstraction. Density functional theory (DFT) studies on the Lewis acid·ether binding energies indicated a trend consistent with the polymerization results. The polymerization mechanism proposed previously for Lewis acid·ether complexes1 adequately explains all the findings. © 2014 American Chemical Society.

  3. Synthesis of highly reactive polyisobutylene catalyzed by EtAlCl 2/Bis(2-chloroethyl) ether soluble complex in hexanes

    KAUST Repository

    Kumar, Rajeev Ananda

    2014-03-25

    The polymerization of isobutylene (IB) to yield highly reactive polyisobutylene (HR PIB) with high exo-olefin content using GaCl3 or FeCl3·diisopropyl ether complexes has been previously reported.1 In an effort to further improve polymerization rates and exo-olefin content, we have studied ethylaluminum dichloride (EADC) complexes with diisopropyl ether, 2-chloroethyl ethyl ether (CEEE), and bis(2-chloroethyl) ether (CEE) as catalysts in conjunction with tert-butyl chloride as initiator in hexanes at different temperatures. All three complexes were readily soluble in hexanes. Polymerization, however, was only observed with CEE. At 0 °C polymerization was complete in 5 min at [t-BuCl] = [EADC·CEE] = 10 mM and resulted in PIB with ∼70% exo-olefin content. Studies on complexation using ATR FTIR and 1H NMR spectroscopy revealed that at 1:1 stoichiometry a small amount of EADC remains uncomplexed. By employing an excess of CEE, exo-olefin contents increased up to 90%, while polymerization rates decreased only slightly. With decreasing temperature, polymerization rates decreased while molecular weights as well as exo-olefin contents increased, suggesting that isomerization has a higher activation energy than β-proton abstraction. Density functional theory (DFT) studies on the Lewis acid·ether binding energies indicated a trend consistent with the polymerization results. The polymerization mechanism proposed previously for Lewis acid·ether complexes1 adequately explains all the findings. © 2014 American Chemical Society.

  4. Spectroscopic (IR, NMR) and conductometric characterization of lithium aluminum hydride - crown ethers complexes [Li{sup +}-C E](A I H{sub 4})- with C E=syn-isomers of DC 18-C-6 in benzene solutions; Caracterisation par spectrometrie (IR, RMN) et conductimetrie des complexes entre le tetrahydrualuminate de lithium LiAIH{sub 4} et l`ether-couronne DC 18-C-6* (isomeres cis-anti-cis et cis-syn-cis) en solution dans le benzene (*2,3,11,12-dicyclohexano-1,4,7,10,13,16-hexacyclooctadecane)

    Energy Technology Data Exchange (ETDEWEB)

    Bastide, J P; Ezzemouri, K; Carre, J; Bouamrane, A; Claudy, P [Institut National des Sciences Appliquees (INSA), 69 - Villeurbanne (France); Frange, B [Faculte des Sciences, 21 - Dijon (France)

    1996-03-01

    [Li{sup +}-C E](AIH{sub 4}){sup -} complexes with C E = syn and anti-isomers of the crown ether DC 18-C-6 have been characterized in benzene solutions by IR (infrared spectroscopy), NMR (nuclear magnetic resonance) and conductometry (at 298 K). The properties of these complexes are closely related to those of the cation [Li{sup +}-C E]. For the anti-isomer, no distortion of the macrocycle was noticed after complexation, the Li{sup +} trapped cation is coordinated with four oxygen atoms of the cavity, and the complex exhibits a covalent behavior. Electrical conductivity of the benzene solution is concentration independent and has a very low mean value ({lambda} = 0,06 {omega}{sup -1}.cm{sup 2}.mol{sup -1}). The macrocycle of the syn-isomer is drastically distorted after complexation. A tridimensional cavity is formed, in which the Li{sup +} trapped cation is coordinated with six oxygen atoms. As a consequence, the species exhibits a high degree of ionic character due to the stretching of the Li{sup +}---(AIH{sub 4}){sup -} bond. Electrical conductivity is enhanced for dilute solutions (x 10 at C 0,01 mol.L{sup -1}). The regular tetrahedral symmetry of (AIH{sub 4}){sup -} anion is retained in the molecular structure of the two complexes. Benzene solutions of [Li-+-syn-DC 18-C-6](AIH{sub 4}){sup -} appear to be the first example of free-(AIH{sub 4}){sup -} anions in a non-polar organic medium. (authors). 22 refs., 3 figs., 4 tabs.

  5. Removal of technetium from alkaline nuclear-waste media by a solvent-extraction process using crown ethers

    International Nuclear Information System (INIS)

    Bonnesen, P.V.; Presley, D.J.; Haverlock, T.J.; Moyer, B.A.

    1995-01-01

    Crown ethers dissolved in suitably modified aliphatic kerosene diluents can be employed to extract technetium as pertechnetate anion (TcO 4 - ) with good extraction ratios from realistic simulants of radioactive alkaline nitrate waste. The modifiers utilized are non-halogenated and non-volatile, and the technetium can be removed from the solvent by stripping using water. The crown ethers bis-4,4'(5')[(tert-butyl)cyclohexano]-18-crown-6 (di-t-BuCH18C6) and dicyclohexano-18-crown-6 (DCH18C6) provide stronger TcO 4 - extraction than dicyclohexano-21-crown-7 and 4-tert-butylcyclohexano 15-crown-5. Whereas DCH18C6 provides somewhat higher TcO 4 - extraction ratios than the more lipophilic di-t-BuCH18C6 derivative, the latter was selected for further study owing to its lower distribution to the aqueous phase. Particularly good extraction and stripping results were obtained with di-t-BuCH 18C6 at 0.02 M in a 2:1 vol/vol blend of tributyl phosphate and Isopar reg-sign M. Using this solvent, 98.9% of the technetium contained (at 6 x 10 -5 M) in a Double-Shell Slurry Feed (DSSF) Hanford tank waste simulant was removed following two cross-current extraction contacts. Two cross-current stripping contacts with deionized water afforded removal of 99.1% of the technetium from the organic solvent

  6. 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

  7. Cosmic Ether

    CERN Document Server

    Tomaschitz, R

    1998-01-01

    A prerelativistic approach to particle dynamics is explored in an expanding Robertson-Walker cosmology. The receding galactic background provides a distinguished frame of reference and a unique cosmic time. In this context the relativistic, purely geometric space-time concept is criticized. Physical space is regarded as a permeable medium, the cosmic ether, which effects the world-lines of particles and rays. We study in detail a Robertson-Walker universe with linear expansion factor and negatively curved, open three-space; we choose the permeability tensor of the ether in such a way that the semiclassical approximation is exact. Galactic red-shifts depend on the refractive index of the ether. In the local Minkowskian limit the ether causes a time variation of mass, which scales inversely proportional to cosmic time. In the globally geodesic rest frames of galactic observers the ether manifests itself in an unbounded speed of signal transfer, in bifurcations of world-lines, and in time inversion effects.

  8. Two-year drinking water carcinogenicity study of methyl tertiary-butyl ether (MTBE) in Wistar rats.

    Science.gov (United States)

    Dodd, Darol; Willson, Gabrielle; Parkinson, Horace; Bermudez, Edilberto

    2013-07-01

    Methyl tertiary-butyl ether (MTBE) has been used as a gasoline additive to reduce tailpipe emissions and its use has been discontinued. There remains a concern that drinking water sources have been contaminated with MTBE. A two-year drinking water carcinogenicity study of MTBE was conducted in Wistar rats (males, 0, 0.5, 3, 7.5 mg ml(-1); and females, 0, 0.5, 3, and 15 mg ml(-1)). Body weights were unaffected and water consumption was reduced in MTBE-exposed males and females. Wet weights of male kidneys were increased at the end of two years of exposure to 7.5 mg ml(-1) MTBE. Chronic progressive nephropathy was observed in males and females, was more severe in males, and was exacerbated in the high MTBE exposure groups. Brain was the only tissue with a statistically significant finding of neoplasms. One astrocytoma (1/50) was found in a female rat (15 mg ml(-1)). The incidence of brain astrocytomas in male rats was 1/50, 1/50, 1/50 and 4/50 for the 0, 0.5, 3 and 7.5 mg ml(-1) exposure groups, respectively. This was a marginally significant statistical trend, but not statistically significant when pairwise comparisons were made or when multiple comparisons were taken into account. The incidence of astrocytoma fell within historical control ranges for Wistar rats, and the brain has not been identified as a target organ following chronic administration of MTBE, ethyl tert-butyl ether, or tertiary butyl alcohol (in drinking water) to mice and rats. We conclude that the astrocytomas observed in this study are not associated with exposure to MTBE. Copyright © 2011 John Wiley & Sons, Ltd.

  9. Alkaline-side extraction of technetium from tank waste using crown ethers and other extractants

    International Nuclear Information System (INIS)

    Bonnesen, P.V.; Moyer, B.A.; Presley, D.J.; Armstrong, V.S.; Haverlock, T.J.; Counce, R.M.; Sachleben, R.A.

    1996-06-01

    The chemical development of a new crown-ether-based solvent-extraction process for the separation of (Tc) from alkaline tank-waste supernate is ready for counter-current testing. The process addresses a priority need in the proposed cleanup of Hanford and other tank wastes. This need has arisen from concerns due to the volatility of Tc during vitrification, as well as 99 Tc's long half-life and environmental mobility. The new process offers several key advantages that direct treatability--no adjustment of the waste composition is needed; economical stripping with water; high efficiency--few stages needed; non-RCRA chemicals--no generation of hazardous or mixed wastes; co-extraction of 90 Sr; and optional concentration on a resin. A key concept advanced in this work entails the use of tandem techniques: solvent extraction offers high selectivity, while a subsequent column sorption process on the aqueous stripping solution serves to greatly concentrate the Tc. Optionally, the stripping solution can be evaporated to a small volume. Batch tests of the solvent-extraction and stripping components of the process have been conducted on actual melton Valley Storage Tank (MVST) waste as well as simulants of MVST and Hanford waste. The tandem process was demonstrated on MVST waste simulants using the three solvents that were selected the final candidates for the process. The solvents are 0.04 M bis-4,4'(5')[(tert-butyl)cyclohexano]-18-crown-6 (abbreviated di-t-BuCH18C6) in a 1:1 vol/vol blend of tributyl phosphate and Isopar reg-sign M (an isoparaffinic kerosene); 0.02 M di-t-BuCH18C6 in 2:1 vol/vol TBP/Isopar M and pure TBP. The process is now ready for counter-current testing on actual Hanford tank supernates

  10. Benzene: questions and answers

    International Nuclear Information System (INIS)

    1999-01-01

    This information booklet is intended to inform residents near natural gas dehydration facilities about benzene and its levels in the atmosphere. It was issued following the federal government's decision to place benzene on its Priority Substances List and to require industry to establish means for reducing benzene emissions from natural gas dehydrators and to inform residents about benzene emissions from glycol dehydration facilities. Accordingly, the booklet explains what benzene is (a colourless flammable liquid component of hydrocarbons) how it gets into the air (during gasoline refining, vehicle refueling and the production of steel and petrochemicals), the associated health hazards (a recognized carcinogen, causing an increased incidence of leukemia in concentrations of 100 parts per million), defines a glycol dehydrator (a facility built at or near some natural gas fields for the removal of water from the natural gas to prevent corrosion and freezing of pipelines), and enumerates the steps that are being taken to reduce benzene levels in the air (benzene levels in gasoline have been reduced, along with benzene emissions from petrochemical plants, refineries, steel plants and glycol dehydrators by 54 per cent to date; this will rise to 90 per cent by 2005). In addition to these actions, industry plans call for all existing glycol dehydrators within 750 metres of any permanent residence to be limited to benzene emissions of no more than three tonnes per year before 2001; new glycol dehydrators after that date will be expected to have benzene emissions reduced to the lowest level that can be practically achieved

  11. STABLE ISOTOPE ANALYSIS OF MTBE TO EVALUATE THE SOURCE OF TBA IN GROUND WATER

    Science.gov (United States)

    Although tert-butyl alcohol (TBA) has not been used as a fuel oxygenate in Orange County, California, the concentrations of TBA in ground water at gasoline spill sites are high compared those of the conventional fuel oxygenate methyl tert-butyl ether (MTBE). In the year 2002, th...

  12. ANAEROBIC DEGRADATION OF MTBE TO TBA IN GROUND WATER AT GASOLINE SPILL SITES IN ORANGE COUNTY, CALIFORNIA

    Science.gov (United States)

    Although tert-Butyl Alcohol (TBA) has not been used as a fuel oxygenate in Orange County, California, the concentrations of TBA in ground water at gasoline spill sites are high compared to the concentrations of the conventional fuel oxygenate Methyl tert-Butyl Ether (MTBE). In t...

  13. Multiple steady states detection in a packed-bed reactive distillation column using bifurcation analysis

    DEFF Research Database (Denmark)

    Ramzan, Naveed; Faheem, Muhammad; Gani, Rafiqul

    2010-01-01

    A packed reactive distillation column producing ethyl tert-butyl ether from tert-butyl alcohol and ethanol was simulated for detection of multiple steady states using Aspen Plus®. A rate-based approach was used to make the simulation model more realistic. A base-case was first developed and fine...

  14. Benzene from Traffic

    DEFF Research Database (Denmark)

    Palmgren, F.; Berkowicz, R.; Skov, H.

    The measurements of benzene showed very clear decreasing trends in the air concentrations and the emissions since 1994. At the same time the measurements of CO and NOx also showed a decreasing trend, but not so strong as for benzene. The general decreasing trend is explained by the increasing...... number of petrol vehicles with three way catalysts, 60-70% in 1999. The very steep decreasing trend for benzene at the beginning of the period from 1994 was explained by the combination of more catalyst vehicles and reduced benzene content in Danish petrol. The total amount of aromatics in petrol......, including toluene, increased only weakly. The analyses of air concentrations were confirmed by analyses of petrol sold in Denmark. The concentration of benzene at Jagtvej in Copenhagen is still in 1998 above the expected new EU limit value, 5 µg/m3 as annual average. However, the reduced content of benzene...

  15. Benzene and its Isomers

    Indian Academy of Sciences (India)

    instantly brings benzene to mind. Benzene is one of the most basic structural units of thousands of the so-called aromatic compounds, which include dyes, drugs, polymers and many more types of compounds that are very useful for our existence and progress. The whole gamut of the chemistry of aromatic compounds, ...

  16. Densities and Kinematic Viscosities for the Systems Benzene + Methyl Formate, Benzene + Ethyl Formate, Benzene + Propyl Formate, and Benzene + Butyl Formate

    DEFF Research Database (Denmark)

    Emmerling, Uwe; Rasmussen, Peter

    1998-01-01

    a Redlich-Kister type of expression with temperature-independent parameters and the data for the systems benzene + ethyl formate, benzene + propyl formate, and benzene + butyl formate with temperature-dependent parameters. The viscosities have furthermore been compared to values predicted by means of the GC......Densities and kinematic viscosities have been measured for the system benzene + methyl formate at 20°C and for the systems benzene + ethyl formate, benzene + propyl formate, and benzene + butyl formate from 20°C to 50°C. The results for the system benzene + methyl formate have been correlated using...

  17. Misconceptions about the ether

    International Nuclear Information System (INIS)

    Duffy, M.C.

    1980-01-01

    Several misconceptions concerning the ether concept and ether models are reviewed and clarified so that the relationship between modern ether theory and orthodox relativity may be better understood. The question of the ether's supposed superfluidity as a concept, and its status in modern physics remains to be answered. (author)

  18. Catalytic hydrolysis of Metil Teret Botil Eter in under ground contaminated water

    International Nuclear Information System (INIS)

    Nikpey, A.; Mortazavi, B.; Asilian, H.; Khavanin, A.; Rezaee, A.; Soleimanian, A.; Kazemian, H.

    2005-01-01

    The behavior of ZSM-5 and Mordenite catalyst in the hydrolysis at room temperature of methyl tert-butyl ether was studied with reference to the possibility of its conversion to more biodegradable products in underground water contaminated by methyl tert-butyl ether. Hydrolysis products were determined using a gas chromatograph equipped with a flame ionization detector. The results indicate that acid ZSM-5 catalyst are effective in both adsorption and hydrolysis of methyl tert-butyl ether and may be applied for both in situ underground water remediation and as protection barrier for wells or leaking tanks. However, acid mordenite catalyst completely inactive

  19. Benzene Monitor System report

    International Nuclear Information System (INIS)

    Livingston, R.R.

    1992-01-01

    Two systems for monitoring benzene in aqueous streams have been designed and assembled by the Savannah River Technology Center, Analytical Development Section (ADS). These systems were used at TNX to support sampling studies of the full-scale open-quotes SRAT/SME/PRclose quotes and to provide real-time measurements of benzene in Precipitate Hydrolysis Aqueous (PHA) simulant. This report describes the two ADS Benzene Monitor System (BMS) configurations, provides data on system operation, and reviews the results of scoping tests conducted at TNX. These scoping tests will allow comparison with other benzene measurement options being considered for use in the Defense Waste Processing Facility (DWPF) laboratory. A report detailing the preferred BMS configuration statistical performance during recent tests has been issued under separate title: Statistical Analyses of the At-line Benzene Monitor Study, SCS-ASG-92-066. The current BMS design, called the At-line Benzene Monitor (ALBM), allows remote measurement of benzene in PHA solutions. The authors have demonstrated the ability to calibrate and operate this system using peanut vials from a standard Hydragard trademark sampler. The equipment and materials used to construct the ALBM are similar to those already used in other applications by the DWPF lab. The precision of this system (±0.5% Relative Standard Deviation (RSD) at 1 sigma) is better than the purge ampersand trap-gas chromatograpy reference method currently in use. Both BMSs provide a direct measurement of the benzene that can be purged from a solution with no sample pretreatment. Each analysis requires about five minutes per sample, and the system operation requires no special skills or training. The analyzer's computer software can be tailored to provide desired outputs. Use of this system produces no waste stream other than the samples themselves (i.e. no organic extractants)

  20. Risk factor benzene

    Energy Technology Data Exchange (ETDEWEB)

    Stobbe, H.

    1981-01-01

    Nearly one hundred years ago clinical and epidemiological studies have already assigned benzene as a markedly haematotoxic substance. Nowadays benzene is known as an important professional noxa, which is straight off directed against the haematopoietic system, essentially to a dose-time-effect. By this it can be taken as a model also for other noxious substances. Similar solvents often contain so-called 'hidden benzene', that means not declared benzene, so that the consumer doesn't know what dangerous substance are available for his personal use. Impairments caused by benzene mostly are manifested earliest after months, years or for tens of years, and the point is, that these haematopoietic disorders are irreversible disturbances of the haematopoietic stem cell compartment. The consequence of this fact is a deep involvement of the proliferation of the erythro-, mono-, granulo- and thrombopoietic cell lines, mostly with predominance of one of these myeloproliferative cell systems. In the further progression of the impairments due to benzene three different clinical pictures can be observed: the aplastic bone marrow syndrome (i.e. aplastic anemia), the haematopoietic dysplasia (i.e. preleukemia) and the acute leukemias (with the subtypes erythroleukosis, myeloblastic-promyelocytic or myelomonocytic from respectively). Also the transition from one clinical picture to another is possible.

  1. Sensitive multiresidue method by HS-SPME/GC-MS for 10 volatile organic compounds in urine matrix: a new tool for biomonitoring studies on children.

    Science.gov (United States)

    Antonucci, Arianna; Vitali, Matteo; Avino, Pasquale; Manigrasso, Maurizio; Protano, Carmela

    2016-08-01

    A HS-SPME method coupled with GC-MS analysis has been developed for simultaneously measuring the concentration of 10 volatile organic compounds (VOCs) (benzene, toluene, ethylbenzene, o-, m-, and p-xylene, methyl tert-butyl ether, ethyl tert-butyl ether, 2-methyl-2-butyl methyl ether, and diisopropyl ether) in urine matrix as a biomonitoring tool for populations at low levels of exposure to such VOCs. These compounds, potentially toxic for human health, are common contaminants of both outdoor and indoor air, as they are released by autovehicular traffic; some of them are also present in environmental tobacco smoke (ETS). Thus, the exposure to these pollutants cannot be neglected and should be assessed. The low limits of detection and quantification (LODs and LOQs <6.5 and 7.5 ng L(-1), respectively) and the high reproducibility (CVs <4 %) make the developed method suited for biomonitoring populations exposed at low levels such as children. Further, the method is cost-effective and low in time-consumption; therefore, it is useful for investigating large populations. It has been applied to children exposed to traffic pollution and/or ETS; the relevant results are reported, and the relevant implications are discussed.

  2. ESTCP Cost and Performance Report. In-Situ Bioremediation of MTBE in Ground Water

    National Research Council Canada - National Science Library

    Miller, Karen

    2003-01-01

    ... (methyl-tert-butyl-ether) and other dissolved gasoline components. It was implemented at the Naval Base Ventura County, Port Hueneme, CA to prevent further contamination of ground water by MTBE leaching from gasoline contaminated soils...

  3. Benzene-centred tripodal diglycolamides for the sequestration of trivalent actinides : Metal ion extraction and luminescence spectroscopic investigations in a room temperature ionic liquid

    NARCIS (Netherlands)

    Ansari, Seraj Ahmad; Mohapatra, Prasanta Kumar; Leoncini, Andrea; Huskens, Jurriaan; Verboom, Willem

    2017-01-01

    Three benzene-centred tripodal diglycolamide (Bz-T-DGA) ligands, where the diglycolamide (DGA) moieties are attached to a central benzene ring through ethylene spacers (LI), amide groups (LII) or ether linkages (LIII), were evaluated for their extraction behaviour towards trivalent actinide and

  4. Economical benzene emission reduction

    International Nuclear Information System (INIS)

    Schuetz, R.

    1999-01-01

    Benzene has been classified as a toxic compound under the Canadian Environmental Protection Act. This has prompted the Alberta Energy and Utilities Board (AEUB) to introduce specific reporting and monitoring guidelines for the oil and gas industry regarding excessive benzene emissions. Glycol dehydration units have been determined to be the major single source of benzene emissions causing air and soil pollution. DualTank Corp. has designed a condensation and storage tank unit to enhance emission reduction, odour elimination and liquid recovery from dehydration units. Their newly designed combined tank unit consists of a large, uninsulated surface area for cooling, and an excessive internal volume for increased retention time. The first prototype was installed in December 1998 at an Enerplus Resources Site. The system provides excellent benzene emission reduction and the elimination of odours and visual plumes. Effective January 1, 1999, the petroleum and natural gas industry must either clean up excessive emissions voluntarily or face government imposed regulations, facility shutdowns and/or fines. 1 fig

  5. Atmospheric benzene and toluene

    International Nuclear Information System (INIS)

    Rasmussen, R.A.; Khalil, M.A.K.

    1983-01-01

    Atmospheric concentrations of benzene (C 6 H 6 ) and toluene (C 7 H 8 )have been observed at nine remote locations of the world ranging in latitude from inside the arctic circle to the south pole. The observations span all seasons at each location. In the northern hemisphere it is observed that C 6 H 6 and C 7 H 8 are most abundant during winter and least abundant during summer. Based on the limited data available, such cycles are not observed in the tropics. These findings are consistent with the expected latitudinal and seasonal variations of OH radicals which cause benzene and toluene to be removed from the atmosphere. The latitude distribution shows high concentrations at mid latitude and low levels in the southern hemisphere. This finding is consistent with the present understanding that the sources of benzene and toluene are primarily anthropogenic. The observed concentration distribution and varibility are consistent with the short expected atmospheric lifetime of the order of months for benzene and days for toluene

  6. Benzene and its Isomers

    Indian Academy of Sciences (India)

    organic chemistry in particular is the period between 1825 when benzene was isolated and 1865 when its correct structure was proposed. Significant initial strides were made during these years in finding new organic reactions and searching for meth- ods to draw molecular structures. For an average chemist the molecular ...

  7. All solid supercapacitor based on polyaniline and crosslinked sulfonated poly[ether ether ketone

    International Nuclear Information System (INIS)

    Sivaraman, P.; Kushwaha, R.K.; Shashidhara, K.; Hande, V.R.; Thakur, A.P.; Samui, A.B.; Khandpekar, M.M.

    2010-01-01

    All solid supercapacitor based on polyaniline (PANI) and crosslinked sulfonated poly[ether ether ketone] (XSPEEK,) is reported in this paper. The crosslinker used for sulfonated poly[ether ether ketone] (SPEEK) is 1,4-bis(hydroxymethyl) benzene. The XSPEEK is used as both solid electrolyte and separator membrane. Supercapacitors are fabricated using various PANI/XSPEEK weight ratios. These are characterized by cyclic voltammetry and galvanostatic charge-discharge studies. The supercapacitor with PANI/XSPEEK weight ratio 1:0.5, exhibit a specific capacitance of 480 F g -1 of PANI. To the best of authors' knowledge, the value reported here is the highest for a supercapacitor based on a proton conducting solid polymer electrolyte and PANI. Detailed electrochemical impedance spectroscopy analysis is carried out. The analysis shows that the complex capacitance of the supercapacitor depends on the XSPEEK content. The time constant (t 0 ), derived from the imaginary part of complex capacitance decreases with increase in the XSPEEK content in the supercapacitor. Cycle life characteristics of the supercapacitor show a decrease in specific capacitance during initial cycles and get stabilized during later cycles.

  8. Benzene exposures in urban areas

    International Nuclear Information System (INIS)

    Valerio, F.; Pala, M.; Cipolla, M.; Stella, A.

    2001-01-01

    Benzene exposures in urban areas were reviewed. Available data confirm that both in USA and Europe, benzene concentrations measured by fixed outdoor monitoring stations underestimate personal exposures of urban residents. Indoor sources, passive smoke and the high exposures during commuting time may explain this difference. Measures in European towns confirm that very frequently mean daily personal exposures to benzene exceed 10 μg/m 3 , current European air quality guideline for this carcinogenic compound [it

  9. Ether formulations of relativity

    International Nuclear Information System (INIS)

    Duffy, M.C.

    1980-01-01

    Contemporary ether theories are surveyed and criticised, especially those formally identical to orthodox Relativity. The historical development of Relativity, Special and General, in terms of an ether, is briefly indicated. Classical interpretations of Generalized Relativity using ether are compared to Euclidean formulations using a background space. The history of a sub-group of theories, formulating a 'new' Relativity involving modified transforms, is outlined. According to the theory with which they agree, recent supposed detections of drift are classified and criticised. Cosmological evidence suggesting an ether is mentioned. Only ether theories formally identical to Relativity have been published in depth. They stand criticised as being contrary to the positivist spirit. The history of mechanical analogues is traced, from Hartley's representing gravitating matter as spherical standing waves, to recent suggestions that vortex-sponge might model electromagnetic, quantum, uncertainty and faster-than-light phenomena. Contemporary theories are particular physical theories, themselves 'second interpretations' of a primary mathematical model. Mechanical analogues are auxiliary, not necessary, to other theory, disclosing relationships between classical and non-classical descriptions of assemblies charging state. The ether-relativity polemic, part of a broader dispute about relativity, is founded on mistaken conceptions of the roles of mathematical and physical models, mechanical analogues; and a distored view of history, which indicates that ether theories have become relativistic. (author)

  10. Relation between photochromic properties and molecular structures in salicylideneaniline crystals.

    Science.gov (United States)

    Johmoto, Kohei; Ishida, Takashi; Sekine, Akiko; Uekusa, Hidehiro; Ohashi, Yuji

    2012-06-01

    The crystal structures of the salicylideneaniline derivatives N-salicylidene-4-tert-butyl-aniline (1), N-3,5-di-tert-butyl-salicylidene-3-methoxyaniline (2), N-3,5-di-tert-butyl-salicylidene-3-bromoaniline (3), N-3,5-di-tert-butyl-salicylidene-3-chloroaniline (4), N-3,5-di-tert-butyl-salicylidene-4-bromoaniline (5), N-3,5-di-tert-butyl-salicylidene-aniline (6), N-3,5-di-tert-butyl-salicylidene-4-carboxyaniline (7) and N-salicylidene-2-chloroaniline (8) were analyzed by X-ray diffraction analysis at ambient temperature to investigate the relationship between their photochromic properties and molecular structures. A clear correlation between photochromism and the dihedral angle of the two benzene rings in the salicylideneaniline derivatives was observed. Crystals with dihedral angles less than 20° were non-photochromic, whereas those with dihedral angles greater than 30° were photochromic. Crystals with dihedral angles between 20 and 30° could be either photochromic or non-photochromic. Inhibition of the pedal motion by intra- or intermolecular steric hindrance, however, can result in non-photochromic behaviour even if the dihedral angle is larger than 30°.

  11. Measurements of activity coefficients at infinite dilution of aliphatic and aromatic hydrocarbons, alcohols, thiophene, tetrahydrofuran, MTBE, and water in ionic liquid [BMIM][SCN] using GLC

    International Nuclear Information System (INIS)

    Domanska, Urszula; Laskowska, Marta

    2009-01-01

    The activity coefficients at infinite dilution, γ 13 ∞ for 32 solutes: alkanes, alken-1-es, alkyn-1-es, cycloalkanes, aromatic hydrocarbons, alcohols, thiophene, tetrahydrofuran, tert-butyl methyl ether, and water in the ionic liquid 1-butyl-3-methylimidazolium thiocyanate [BMIM][SCN] were determined by gas-liquid chromatography at the temperatures from 298.15 K to 368.15 K. The values of the partial molar excess enthalpies at infinite dilution ΔH 1 E,∞ were calculated from the experimental γ 13 ∞ values obtained over the temperature range. The selectivities for the hexane/benzene, cyclohexane/benzene, hexane/thiophene, and other separation problems were calculated from the γ 13 ∞ and compared to the other ionic liquids, N-methyl-2-pyrrolidinone, and sulfolane, taken from the recent literature. This work demonstrates that with chosen ionic liquid it is possible to separate different organic compounds with the highest selectivity, ever published

  12. Back-biting termination in methyl methacrylate/tert-butyl acrylate anionic block copolymerization

    Czech Academy of Sciences Publication Activity Database

    Čadová, Eva; Dybal, Jiří; Kříž, Jaroslav; Vlček, Petr; Janata, Miroslav; Toman, Luděk

    2008-01-01

    Roč. 209, č. 16 (2008), s. 1657-1665 ISSN 1022-1352 Institutional research plan: CEZ:AV0Z40500505 Keywords : acrylates * anionic polymerization * spontaneous termination Subject RIV: CD - Macromolecular Chemistry Impact factor: 2.202, year: 2008

  13. Inhibition of Palmityl Carnitine Oxidation in Rat Liver Mitochondria by Tert-Butyl Hydroperoxide

    Czech Academy of Sciences Publication Activity Database

    Červinková, Z.; Rauchová, Hana; Křiváková, P.; Drahota, Zdeněk

    2008-01-01

    Roč. 57, č. 1 (2008), s. 133-136 ISSN 0862-8408 R&D Projects: GA ČR(CZ) GD303/03/H065; GA ČR(CZ) GA305/04/0500; GA MŠk(CZ) 1M0520 Institutional research plan: CEZ:AV0Z50110509 Keywords : liver mitochondria * palmityl carnitine oxidation * tert-butylhydroperoxide Subject RIV: ED - Physiology Impact factor: 1.653, year: 2008

  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" : un terme utilisé pour décrire des espèces vermiformes subissant des réactions de scission/recombinaison en compétition principalement avec les mouvements de reptation des chaînes. Le système constitué de fils moléculaires (17,5 Å de diamètre) de Cu2(O2C-CH(C2H5)C4H9)4 dans le solvant apolaire est typique de “polymères vivants” où le mécanisme de scission réversible prévaut plutôt que les mécanismes impliquant des nœuds transitoires branchés. La dynamique dans le domaine des hautes fréquences évolue d'un régime où la reptation est le mécanisme de relaxation dominant vers un régime intermédiaire où les modes de “respiration” et de Rouse deviennent importants. D'importantes modifications de la relaxation de contrainte se produisent pour les systèmes concentrés. Le système binaire est le premier exemple de “polymère vivant” en milieu organique et présente des modules élastiques (G ≈ ca. 120 Pa à φ = 1 %) qui sont au moins 20 fois plus grands que ceux des homologues aqueux.

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

    Directory of Open Access Journals (Sweden)

    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.

  16. 4,4′-Di-tert-butyl-2,2′-bipyridine

    Directory of Open Access Journals (Sweden)

    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.

  17. Ultrasound-assisted oxidative desulfurization of bunker-C oil using tert-butyl hydroperoxide.

    Science.gov (United States)

    Tang, Qiong; Lin, Song; Cheng, Ying; Liu, Sujun; Xiong, Jun-Ru

    2013-09-01

    This work investigated the ultrasonic assisted oxidative desulfurization of bunker-C oil with TBHP/MoO3 system. The operational parameters for the desulfurization procedure such as ultrasonic irradiation time, ultrasonic wave amplitude, catalyst initial concentration and oxidation agent initial concentration were studied. The experimental results show that the present oxidation system was very efficient for the desulfurization of bunker-C oil and ~35% sulfur was removed which was dependent on operational parameters. The application of ultrasonic irradiation allowed sulfur removal in a shorter time. The stronger the solvent polarity is, the higher the sulfur removal rate, but the recovery rate of oil is lower. The sulfur compounds in bunker-C oil reacted with TBHP to produce corresponding sulfoxide, and further oxidation produced the corresponding sulfone. Copyright © 2013 Elsevier B.V. All rights reserved.

  18. rac-tert-Butyl{2-hydroxy-2-[4-hydroxy-3-(hydroxymethylphenyl]ethyl}azanium acrylate

    Directory of Open Access Journals (Sweden)

    Wenju Liu

    2017-08-01

    Full Text Available The title salt, C13H22NO3+·C3H3O2−, comprises one salbutamol cation and an acrylate anion. The acrylate anion is linked to the salbutamol cation via an O—H...O and an N—H...O hydrogen bond. The C=C group of the acrylate anion is disordered over two positions, with refined site occupancies of 0.812 (7 and 0.188 (7. The crystal structure is stabilized by N—H...O and O—H...O hydrogen-bonding interactions.

  19. Rearrangements in the halogenation of tetraalkylethylenes with N-halosuccinimides and tert-butyl hypochlorite

    NARCIS (Netherlands)

    Meijer, E.W.; Kellogg, R.M.; Wynberg, H.

    1982-01-01

    The reaction of N-halosuccinimides and Me3COCl with tetraalkylethylenes involves halo-cation addn. to the double bond in a fast reaction, followed by abstraction of an allylic proton, resulting in a double bond shift. Homoallylic halogenation occurs in tetraalkylethylenes which can not undergo a

  20. 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.

  1. tert-Butyl 4-carbamoyl-3-methoxyimino-4-methylpiperidine-1-carboxylate

    Directory of Open Access Journals (Sweden)

    Yucheng Wang

    2008-12-01

    Full Text Available The title compound, C13H23N3O4, was prepared starting from ethyl N-benzyl-3-oxopiperidine-4-carboxylate through a nine-step reaction, including hydrogenation, Boc (tert-butoxycarbonyl protection, methylation, oximation, hydrolysis, esterification and ammonolysis. In the crystal structure, molecules are linked by intermolecular N—H...O hydrogen bonds to form a porous three-dimensional network with solvent-free hydrophobic channels extending along the c axis.

  2. IRIS Toxicological Review of Tert-Butyl Alcohol (Tert-Butanol) (Preliminary Assessment Materials)

    Science.gov (United States)

    In August 2013, EPA released the draft literature searches and associated search strategies, evidence tables, and exposure response arrays for TBA to obtain input from stakeholders and the public prior to developing the draft IRIS assessment. Specifically, EPA was interested in c...

  3. Absorption, Distribution, and Clearanace o f2,6-Di-tert-Butyl-4-nitrophenol (DBNP)

    National Research Council Canada - National Science Library

    Still, K

    2002-01-01

    .... DBNP is produced when oil mist from synthetic steam turbine lubricants containing the antioxidant 2,6-Di-tert-butylphenol is nitrated during passage through the submarine air filtration system...

  4. Di-tert-butyl-bis(N-isopropyl-N-methyl-dithio-carbamato-κS,S')tin(IV).

    Science.gov (United States)

    Muthalib, Amirah Faizah; Baba, Ibrahim; Samsudin, Mohd Wahid; Ng, Seik Weng

    2010-03-03

    The dithio-carbamate anions in the title compound, [Sn(C(4)H(9))(2)(C(5)H(10)NS(2))(2)], chelate to the Sn(IV) atom, which is six-coordinated in a skew-trapezoidal-bipyramidal geometry. The mol-ecule lies across a twofold rotation axis. The crystal studied was a non-merohedral twin, the ratio of the twin components being 0.82 (1):0.18 (1).

  5. Synthesis, structure, and sunlight photolysis of benzyl- and tert-butyl-substituted octamethyltitanocene dihydrosulfides

    Czech Academy of Sciences Publication Activity Database

    Horáček, Michal; Císařová, I.; Gyepes, R.; Kubišta, Jiří; Pinkas, Jiří; Lamač, Martin; Mach, Karel

    2014-01-01

    Roč. 755, APR 2014 (2014), s. 141-150 ISSN 0022-328X R&D Projects: GA ČR(CZ) GAP207/12/2368; GA ČR GP203/09/P276 Institutional support: RVO:61388955 Keywords : titanium * titanocene * hydrosulphide Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.173, year: 2014

  6. Electrorheological Properties of Suspensions Prepared from Poly(Li-tert-butyl methacrylate) Ionomer

    OpenAIRE

    YAVUZ, Mustafa

    2014-01-01

    The synthesis, characterisation and partial hydrolysis of poly(tert-butylmethacrylate), (PTBMA), and the electrorheological (ER) properties of its suspensions were investigated. The polymer was synthesised by radical polymerisation and partially hydrolysed by para-toluenesulphonic acid monohydrate (PTSA.H2O), and then converted to a lithium salt (PTBMA-Li) by washing with a LiOH(aq) solution. From particle size measurements, the average particle size of PTBMA-Li was determined to be ...

  7. Protective effect of nuclear factor E2-related factor 2 on inflammatory cytokine response to brominated diphenyl ether-47 in the HTR-8/SVneo human first trimester extravillous trophoblast cell line.

    Science.gov (United States)

    Park, Hae-Ryung; Loch-Caruso, Rita

    2014-11-15

    Polybrominated diphenyl ethers (PBDEs) are widely used flame retardants, and BDE-47 is a prevalent PBDE congener detected in human tissues. Exposure to PBDEs has been linked to adverse pregnancy outcomes in humans. Although the underlying mechanisms of adverse birth outcomes are poorly understood, critical roles for oxidative stress and inflammation are implicated. The present study investigated antioxidant responses in a human extravillous trophoblast cell line, HTR-8/SVneo, and examined the role of nuclear factor E2-related factor 2 (Nrf2), an antioxidative transcription factor, in BDE-47-induced inflammatory responses in the cells. Treatment of HTR-8/SVneo cells with 5, 10, 15, and 20μM BDE-47 for 24h increased intracellular glutathione (GSH) levels compared to solvent control. Treatment of HTR-8/SVneo cells with 20μM BDE-47 for 24h induced the antioxidant response element (ARE) activity, indicating Nrf2 transactivation by BDE-47 treatment, and resulted in differential expression of redox-sensitive genes compared to solvent control. Pretreatment with tert-butyl hydroquinone (tBHQ) or sulforaphane, known Nrf2 inducers, reduced BDE-47-stimulated IL-6 release with increased ARE reporter activity, reduced nuclear factor kappa B (NF-κB) reporter activity, increased GSH production, and stimulated expression of antioxidant genes compared to non-Nrf2 inducer pretreated groups, suggesting that Nrf2 may play a protective role against BDE-47-mediated inflammatory responses in HTR-8/SVneo cells. These results suggest that Nrf2 activation significantly attenuated BDE-47-induced IL-6 release by augmentation of cellular antioxidative system via upregulation of Nrf2 signaling pathways, and that Nrf2 induction may be a potential therapeutic target to reduce adverse pregnancy outcomes associated with toxicant-induced oxidative stress and inflammation. Copyright © 2014 Elsevier Inc. All rights reserved.

  8. Laboratory evidence of MTBE biodegradation in Borden aquifer material

    Science.gov (United States)

    Schirmer, Mario; Butler, Barbara J.; Church, Clinton D.; Barker, James F.; Nadarajah, Nalina

    2003-02-01

    Mainly due to intrinsic biodegradation, monitored natural attenuation can be an effective and inexpensive remediation strategy at petroleum release sites. However, gasoline additives such as methyl tert-butyl ether (MTBE) can jeopardize this strategy because these compounds often degrade, if at all, at a slower rate than the collectively benzene, toluene, ethylbenzene and the xylene (BTEX) compounds. Investigation of whether a compound degrades under certain conditions, and at what rate, is therefore important to the assessment of the intrinsic remediation potential of aquifers. A natural gradient experiment with dissolved MTBE-containing gasoline in the shallow, aerobic sand aquifer at Canadian Forces Base (CFB) Borden (Ontario, Canada) from 1988 to 1996 suggested that biodegradation was the main cause of attenuation for MTBE within the aquifer. This laboratory study demonstrates biologically catalyzed MTBE degradation in Borden aquifer-like environments, and so supports the idea that attenuation due to biodegradation may have occurred in the natural gradient experiment. In an experiment with batch microcosms of aquifer material, three of the microcosms ultimately degraded MTBE to below detection, although this required more than 189 days (or >300 days in one case). Failure to detect the daughter product tert-butyl alcohol (TBA) in the field and the batch experiments could be because TBA was more readily degradable than MTBE under Borden conditions.

  9. A highly sensitive and selective dimethyl ether sensor based on cataluminescence.

    Science.gov (United States)

    Zhang, Runkun; Cao, Xiaoan; Liu, Yonghui; Peng, Yan

    2010-07-15

    A sensor for detecting dimethyl ether was designed based on the cataluminescence phenomenon when dimethyl ether vapors were passing through the surface of the ceramic heater. The proposed sensor showed high sensitivity and selectivity to dimethyl ether at an optimal temperature of 279 degrees C. Quantitative analysis were performed at a wavelength of 425 nm, the flow rate of carrier air is around 300 mL/min. The linear range of the cataluminescence intensity versus concentration of dimethyl ether is 100-6.0x10(3) ppm with a detection limit of 80 ppm. The sensor response time is 2.5 s. Under the optimized conditions, none or only very low levels of interference were observed while the foreign substances such as benzene, formaldehyde, ammonia, methanol, ethanol, acetaldehyde, acetic acid, acrolein, isopropyl ether, ethyl acetate, glycol ether and 2-methoxyethanol were passing through the sensor. Since the sensor does not need to prepare and fix up the granular catalyst, the simple technology reduces cost, improves stability and extends life span. The method can be applied to facilitate detection of dimethyl ether in the air. The possible mechanism of cataluminescence from the oxidation of dimethyl ether on the surface of ceramic heater was discussed based on the reaction products. Copyright 2010 Elsevier B.V. All rights reserved.

  10. Usage of the word 'ether'

    International Nuclear Information System (INIS)

    Duffy, M.C.

    1980-01-01

    Confusion has been caused by scientists using the one word 'ether' to classify models differing from each other in important respects. Major roles assigned to the word are examined, and the nature of modern ether theories surveyed. The part played by the several meanings attached to the word, in the ether concept, is outlined. (author)

  11. Benzene formation in electronic cigarettes.

    Directory of Open Access Journals (Sweden)

    James F Pankow

    Full Text Available The heating of the fluids used in electronic cigarettes ("e-cigarettes" used to create "vaping" aerosols is capable of causing a wide range of degradation reaction products. We investigated formation of benzene (an important human carcinogen from e-cigarette fluids containing propylene glycol (PG, glycerol (GL, benzoic acid, the flavor chemical benzaldehyde, and nicotine.Three e-cigarette devices were used: the JUULTM "pod" system (provides no user accessible settings other than flavor cartridge choice, and two refill tank systems that allowed a range of user accessible power settings. Benzene in the e-cigarette aerosols was determined by gas chromatography/mass spectrometry. Benzene formation was ND (not detected in the JUUL system. In the two tank systems benzene was found to form from propylene glycol (PG and glycerol (GL, and from the additives benzoic acid and benzaldehyde, especially at high power settings. With 50:50 PG+GL, for tank device 1 at 6W and 13W, the formed benzene concentrations were 1.9 and 750 μg/m3. For tank device 2, at 6W and 25W, the formed concentrations were ND and 1.8 μg/m3. With benzoic acid and benzaldehyde at ~10 mg/mL, for tank device 1, values at 13W were as high as 5000 μg/m3. For tank device 2 at 25W, all values were ≤~100 μg/m3. These values may be compared with what can be expected in a conventional (tobacco cigarette, namely 200,000 μg/m3. Thus, the risks from benzene will be lower from e-cigarettes than from conventional cigarettes. However, ambient benzene air concentrations in the U.S. have typically been 1 μg/m3, so that benzene has been named the largest single known cancer-risk air toxic in the U.S. For non-smokers, chronically repeated exposure to benzene from e-cigarettes at levels such as 100 or higher μg/m3 will not be of negligible risk.

  12. Story of skeletally substituted benzenes

    Indian Academy of Sciences (India)

    Unknown

    values are extensively used to define aromaticity quantitatively.3 In a recent study on ... studies were directed to unravel the subtle ways in which the stability, reactivity, and ..... The singlet–triplet gaps of all the skeletally substituted benzenes ...

  13. Benzene adsorption and oxidation on Ir(111)

    NARCIS (Netherlands)

    Weststrate, C.J.; Bakker, J.W.; Gluhoi, A.C.; Ludwig, W.; Nieuwenhuys, B.E.

    2007-01-01

    Adsorption, decompn. and oxidn. of benzene on Ir(1 1 1) was studied by high resoln. (synchrotron) XPS, temp. programmed desorption and LEED. Mol. adsorption of benzene on Ir(1 1 1) is obsd. between 170 K and 350 K. Above this temp. both desorption and decompn. of benzene take place. An ordered

  14. Direct measurement of VOC diffusivities in tree tissues

    DEFF Research Database (Denmark)

    Baduru, K.K.; Trapp, Stefan; Burken, Joel G.

    2008-01-01

    Recent discoveries in the phytoremediation of volatile organic compounds (VOCs) show that vapor-phase transport into roots leads to VOC removal from the vadose zone and diffusion and volatilization out of plants is an important fate following uptake. Volatilization to the atmosphere constitutes one...... in numerous vegetation−VOC interactions, including the phytoremediation of soil vapors and dissolved aqueous-phase contaminants. The diffusion of VOCs through freshly excised tree tissue was directly measured for common groundwater contaminants, chlorinated compounds such as trichloroethylene, perchloroethene......, and tetrachloroethane and aromatic hydrocarbons such as benzene, toluene, and methyl tert-butyl ether. All compounds tested are currently being treated at full scale with tree-based phytoremediation. Diffusivities were determined by modeling the diffusive transport data with a one-dimensional diffusive flux model...

  15. Extraction of hafnium by 1-phenyl-3-methyl-4-benzoyl-5-pyralozone from aqueous-alcoholic solutions

    International Nuclear Information System (INIS)

    Hala, J.; Prihoda, J.

    1975-01-01

    Extraction of hafnium by 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone (HL) in benzene, toluene, chloroform and tetrachloromethane from aqueous-alcoholic solutions of the formal acidity of 2M-HClO 4 was studied. Methyl, ethyl, n- and isopropyl, tert-butyl and allyl alcohol as well as ethylene glycol monomethyl ether and propylene glycol were used as organic components of the mixed aqueous-organic phase. Their presence in some cases resulted in a synergic increase in the distribution ratio of hafnium. The increase is interpreted using the results of a slope analysis and measurements of the alcohol distribution and the relative permittivity of the organic phase. It is suggested that HfL 4 molecules were solvated by alcohol molecules in the organic phase. At high alcohol concentration synergism changed into antagonism. This was caused by changes in the distribution of HL and its interaction with the alcohol in the organic phase. (author)

  16. Reproductive toxicity of the glycol ethers.

    Science.gov (United States)

    Hardin, B D

    1983-06-01

    The glycol ethers are an important and widely used class of solvents. Recent studies have demonstrated that ethylene glycol monomethyl ether (EGME), ethylene glycol dimethyl ether (EGdiME), ethylene glycol monoethyl ether (EGEE), and ethylene glycol monoethyl ether acetate (EGEEA) are teratogenic. Other studies have demonstrated that testicular atrophy or infertility follow treatment of males with EGME, ethylene glycol monomethyl ether acetate (EGMEA), EGEE, EGEEA, diethylene glycol dimethyl ether (diEGdiME), and diethylene glycol monoethyl ether (diEGEE). Experimental data are reviewed and structure-activity relationships are speculated upon.

  17. On the Use of Potential Denaturing Agents for Ethanol in Direct Ethanol Fuel Cells

    Directory of Open Access Journals (Sweden)

    Domnik Bayer

    2011-01-01

    Full Text Available Acidic or alkaline direct ethanol fuel cells (DEFCs can be a sustainable alternative for power generation if they are fuelled with bio-ethanol. However, in order to keep the fuel cheap, ethanol has to be exempted from tax on spirits by denaturing. In this investigation the potential denaturing agents fusel oil, tert-butyl ethyl ether, and Bitrex were tested with regard to their compatibility with fuel cells. Experiments were carried out both in sulphuric acid and potassium hydroxide solution. Beside, basic electrochemical tests, differential electrochemical mass spectrometry (DEMS and fuel cell tests were conducted. It was found that fusel oil is not suitable as denaturing agent for DEFC. However, tert-butyl ethyl ether does not seem to hinder the ethanol conversion as much. Finally, a mixture of tert-butyl ethyl ether and Bitrex can be proposed as promising candidate as denaturing agent for use in acidic and alkaline DEFC.

  18. Mechanistic considerations in benzene physiological model development.

    OpenAIRE

    Medinsky, M A; Kenyon, E M; Seaton, M J; Schlosser, P M

    1996-01-01

    Benzene, an important industrial solvent, is also present in unleaded gasoline and cigarette smoke. The hematotoxic effects of benzene in humans are well documented and include aplastic anemia, pancytopenia, and acute myelogenous leukemia. However, the risks of leukemia at low exposure concentrations have not been established. A combination of metabolites (hydroquinone and phenol, for example) may be necessary to duplicate the hematotoxic effect of benzene, perhaps due in part to the synergis...

  19. Muonium radicals in benzene-styrene mixtures

    International Nuclear Information System (INIS)

    Ng, B.W.; Stadlbauer, J.W.; Walker, D.C.

    1984-01-01

    Muonium radicals were observed through their μ + SR precession frequencies in high transverse magnetic fields in pure benzene, pure styrene and their mixtures, all as liquids at room temperature. In benzene-styrene mixtures, the radicals obtained in each pure liquid are both present, so no slow (10 -9 -10 -5 s) intermolecular exchange occurs; but strong selectivity was found with the formation of the radical from styrene being about eight-times more probable than the radical from benzene. (Auth.)

  20. Effect of repeated benzene inhalation exposures on benzene metabolism, binding to hemoglobin, and induction of micronuclei

    International Nuclear Information System (INIS)

    Sabourin, P.J.; Sun, J.D.; MacGregor, J.T.; Wehr, C.M.; Birnbaum, L.S.; Lucier, G.; Henderson, R.F.

    1990-01-01

    Metabolism of benzene is thought to be necessary to produce the toxic effects, including carcinogenicity, associated with benzene exposure. To extrapolate from the results of rodent studies to potential health risks in man, one must know how benzene metabolism is affected by species, dose, dose rate, and repeated versus single exposures. The purpose of our studies was to determine the effect of repeated inhalation exposures on the metabolism of [14C]benzene by rodents. Benzene metabolism was assessed by characterizing and quantitating urinary metabolites, and by quantitating 14C bound to hemoglobin and micronuclei induction. F344/N rats and B6C3F1 mice were exposed, nose-only, to 600 ppm benzene or to air (control) for 6 hr/day, 5 days/week for 3 weeks. On the last day, both benzene-pretreated and control animals were exposed to 600 ppm, 14C-labeled benzene for 6 hr. Individual benzene metabolites in urine collected for 24 hr after the exposure were analyzed. There was a significant decrease in the respiratory rate of mice (but not rats) pretreated with benzene which resulted in lower levels of urinary [14C]benzene metabolites. The analyses indicated that the only effects of benzene pretreatment on the metabolite profile in rat or mouse urine were a slight shift from glucuronidation to sulfation in mice and a shift from sulfation to glucuronidation in rats. Benzene pretreatment also had no effect, in either species, on formation of [14C]benzene-derived hemoglobin adducts. Mice and rats had similar levels of hemoglobin adduct binding, despite the higher metabolism of benzene by mice. This indicates that hemoglobin adduct formation occurs with higher efficiency in rats. After 1 week of exposure to 600 ppm benzene, the frequency of micronucleated, polychromatic erythrocytes (PCEs) in mice was significantly increased

  1. Preparation and Characterization of Sulfonated Poly (ether ether ...

    African Journals Online (AJOL)

    NJD

    2007-08-10

    Aug 10, 2007 ... Preparation and Characterization of Sulfonated Poly (ether ... Currently perfluori- ... with phosphoric acid solution according to the method described earlier.11,12 ... where A is the membrane area available for diffusion; CA is.

  2. Ether the nothing that connects everything

    CERN Document Server

    Milutis, Joe

    2006-01-01

    In Ether, the histories of the unseen merge with discussions of the technology of electromagnetism. Navigating more than three hundred years of the ether''s cultural and artistic history, Joe Milutis reveals its continuous reinvention and tangible impact without ever losing sight of its ephemeral, elusive nature. The true meaning of ether, Milutis suggests, may be that it can never be fully grasped.

  3. Occupational exposure to benzene in South Korea.

    Science.gov (United States)

    Kang, Seong-Kyu; Lee, Mi-Young; Kim, Tae-Kyun; Lee, Jeong-Oh; Ahn, Yeon Soon

    2005-05-30

    Benzene has been used in various industries as glues or solvents in Korea. Since 1981, a preparation containing more than 1% benzene is not allowed to be manufactured, used or dealt with in the workplace, except in laboratories and in those situations benzene must be used in a completely sealed process as specified in Industrial Safety and Health Act (ISHA). Claims for compensation of hematopoietic diseases related to benzene have been rising even though the work environment has been improved. This study was conducted to assess the status of benzene exposure in different industries in Korea. We reviewed the claimed cases investigated by the Korea Occupational Safety and Health Agency (KOSHA) between 1992 and 2000. The Survey of National Work Environment Status in 1998 was analyzed to assume the number of workers and factories exposed to benzene. In 2000, six factories were investigated to evaluate benzene exposure. Personal air monitoring was performed in 61 workers and urine samples were collected from 57 workers to measure trans,trans-muconic acid (t,t-MA). Hematologic examination has performed. Thirty-four cases of hematopoietic diseases were investigated by KOSHA including eight cases of myelodysplastic syndrome and eight cases of acute myelocytic leukemia. Eight cases were accepted as related to benzene exposure. The number of workers possibly exposed to benzene can be estimated to be 196,182 workers from 6219 factories based on the database. The geometric mean of benzene in air was 0.094 (0.005-5.311) ppm. Seven samples were higher than 1 ppm but they did not go over the 10 ppm occupational exposure limit (OEL) value in Korea. The geometric mean of trans,trans-muconic acid in urine was 0.966 (0.24-2.74) mg/g creatinine. The benzene exposure level was low except in a factory where benzene was used to polymerize other chemicals. The ambient benzene from 0.1 to 1 ppm was significantly correlated with urine t,t-MA concentration (r=0.733, p<0.01). Hematologic

  4. Mechanistic considerations in benzene physiological model development.

    Science.gov (United States)

    Medinsky, M A; Kenyon, E M; Seaton, M J; Schlosser, P M

    1996-12-01

    Benzene, an important industrial solvent, is also present in unleaded gasoline and cigarette smoke. The hematotoxic effects of benzene in humans are well documented and include aplastic anemia, pancytopenia, and acute myelogenous leukemia. However, the risks of leukemia at low exposure concentrations have not been established. A combination of metabolites (hydroquinone and phenol, for example) may be necessary to duplicate the hematotoxic effect of benzene, perhaps due in part to the synergistic effect of phenol on myeloperoxidase-mediated oxidation of hydroquinone to the reactive metabolite benzoquinone. Because benzene and its hydroxylated metabolites (phenol, hydroquinone, and catechol) are substrates for the same cytochrome P450 enzymes, competitive interactions among the metabolites are possible. In vivo data on metabolite formation by mice exposed to various benzene concentrations are consistent with competitive inhibition of phenol oxidation by benzene. In vitro studies of the metabolic oxidation of benzene, phenol, and hydroquinone are consistent with the mechanism of competitive interaction among the metabolites. The dosimetry of benzene and its metabolites in the target tissue, bone marrow, depends on the balance of activation processes such as enzymatic oxidation and deactivation processes such as conjugation and excretion. Phenol, the primary benzene metabolite, can undergo both oxidation and conjugation. Thus the potential exists for competition among various enzymes for phenol. Zonal localization of phase I and phase II enzymes in various regions of the liver acinus also impacts this competition. Biologically based dosimetry models that incorporate the important determinants of benzene flux, including interactions with other chemicals, will enable prediction of target tissue doses of benzene and metabolites at low exposure concentrations relevant for humans.

  5. Efficacy of Ultrasonic Homogenization in the Separation of Benzene-n-Heptane Mixture by Liquid Membrane

    Energy Technology Data Exchange (ETDEWEB)

    Kim, B.S.; Chung, T.S. [Department of Chemical Engineering, Sung Kyun Kwan University, Seoul (Korea)

    1999-04-01

    In the separation of benzene-n-heptane mixture by liquid membrane, the efficacy of ultrasonic homogenization in emulsification was studied with two anionic surfactants. The two anionic surfactants used were triethanolamine lauryl sulfate and sodium polyoxyethylene(2) lauryl ether sulfate. The two anionic surfactants used were triethanolamine lauryl sulfate and sodium polyoxyethylene(2) lauryl ether stifle. The highest value of the separation factor obtained by ultrasonic homogenization was approximately three times as large as that for triethanolamine lauryl sulfate and one and a half times as large as that for sodium polyoxyethylene(2) lauryl sulfate when the mechanical stirring was used on the same operational conditions. The lowest membrane breakup was observed when the highest value of the separation factor was achieved with sodium polyoxyethylene(2) lauryl sulfate. 14 refs., 7 figs., 1 tab.

  6. Chemoselective Deprotection of Triethylsilyl Ethers

    Science.gov (United States)

    Chandra, Tilak; Broderick, William E.; Broderick, Joan B.

    2009-01-01

    An efficient and selective method was developed for the deprotection of triethylsilyl (TES) ethers using formic acid in methanol (5–10%) or in methylene chloride 2–5%) with excellent yields. TES ethers are selectively deprotected to the corresponding alcohols in high yields using formic acid in methanol under mild reaction conditions. Other hydroxyl protecting groups like t-butyldimethylsilyl (TBDMS) remain unaffected. PMID:20183570

  7. Rearrangements of Cycloalkenyl Aryl Ethers

    Directory of Open Access Journals (Sweden)

    Mercedesz Törincsi

    2016-04-01

    Full Text Available Rearrangement reactions of cycloalkenyl phenol and naphthyl ethers and the acid-catalyzed cyclization of the resulting product were investigated. Claisen rearrangement afforded 2-substituted phenol and naphthol derivatives. Combined Claisen and Cope rearrangement resulted in the formation of 4-substituted phenol and naphthol derivatives. In the case of cycloocthylphenyl ether the consecutive Claisen and Cope rearrangements were followed by an alkyl migration. The mechanism of this novel rearrangement reaction is also discussed.

  8. Ether: Bitcoin's competitor or ally?

    OpenAIRE

    Bouoiyour, Jamal; Selmi, Refk

    2017-01-01

    Although Bitcoin has long been dominant in the crypto scene, it is certainly not alone. Ether is another cryptocurrency related project that has attracted an intensive attention because of its additional features. This study seeks to test whether these cryptocurrencies differ in terms of their volatile and speculative behaviors, hedge, safe haven and risk diversification properties. Using different econometric techniques, we show that a) Bitcoin and Ether are volatile and relatively more resp...

  9. Determination of average molecular weights on organic reactor coolants. II.-Freezing point depression method for diphenyl-ether solutions

    International Nuclear Information System (INIS)

    Carreira, M.

    1965-01-01

    In order to reduce limitations of solubility, the cryoscopic method developed for benzene solutions of polyphenyl mixtures has been extended to diphenyl-ether solutions by introducing some modifications imposed by the physico-chemical properties of this solvent. The Nernsto theory of Beckman's method has been revised, taking into account the heat-transfer characteristics of the system, and the results of that analysis have been used to fix upon the design parameters of a cryoscopic apparatus for measurements on diphenyl-ether solutions. (Author) 9 refs

  10. Protective effect of nuclear factor E2-related factor 2 on inflammatory cytokine response to brominated diphenyl ether-47 in the HTR-8/SVneo human first trimester extravillous trophoblast cell line

    International Nuclear Information System (INIS)

    Park, Hae-Ryung; Loch-Caruso, Rita

    2014-01-01

    Polybrominated diphenyl ethers (PBDEs) are widely used flame retardants, and BDE-47 is a prevalent PBDE congener detected in human tissues. Exposure to PBDEs has been linked to adverse pregnancy outcomes in humans. Although the underlying mechanisms of adverse birth outcomes are poorly understood, critical roles for oxidative stress and inflammation are implicated. The present study investigated antioxidant responses in a human extravillous trophoblast cell line, HTR-8/SVneo, and examined the role of nuclear factor E2-related factor 2 (Nrf2), an antioxidative transcription factor, in BDE-47-induced inflammatory responses in the cells. Treatment of HTR-8/SVneo cells with 5, 10, 15, and 20 μM BDE-47 for 24 h increased intracellular glutathione (GSH) levels compared to solvent control. Treatment of HTR-8/SVneo cells with 20 μM BDE-47 for 24 h induced the antioxidant response element (ARE) activity, indicating Nrf2 transactivation by BDE-47 treatment, and resulted in differential expression of redox-sensitive genes compared to solvent control. Pretreatment with tert-butyl hydroquinone (tBHQ) or sulforaphane, known Nrf2 inducers, reduced BDE-47-stimulated IL-6 release with increased ARE reporter activity, reduced nuclear factor kappa B (NF-κB) reporter activity, increased GSH production, and stimulated expression of antioxidant genes compared to non-Nrf2 inducer pretreated groups, suggesting that Nrf2 may play a protective role against BDE-47-mediated inflammatory responses in HTR-8/SVneo cells. These results suggest that Nrf2 activation significantly attenuated BDE-47-induced IL-6 release by augmentation of cellular antioxidative system via upregulation of Nrf2 signaling pathways, and that Nrf2 induction may be a potential therapeutic target to reduce adverse pregnancy outcomes associated with toxicant-induced oxidative stress and inflammation. - Highlights: • BDE-47 stimulated ARE reporter activity and GSH production. • BDE-47 resulted in differential

  11. Protective effect of nuclear factor E2-related factor 2 on inflammatory cytokine response to brominated diphenyl ether-47 in the HTR-8/SVneo human first trimester extravillous trophoblast cell line

    Energy Technology Data Exchange (ETDEWEB)

    Park, Hae-Ryung, E-mail: heaven@umich.edu; Loch-Caruso, Rita

    2014-11-15

    Polybrominated diphenyl ethers (PBDEs) are widely used flame retardants, and BDE-47 is a prevalent PBDE congener detected in human tissues. Exposure to PBDEs has been linked to adverse pregnancy outcomes in humans. Although the underlying mechanisms of adverse birth outcomes are poorly understood, critical roles for oxidative stress and inflammation are implicated. The present study investigated antioxidant responses in a human extravillous trophoblast cell line, HTR-8/SVneo, and examined the role of nuclear factor E2-related factor 2 (Nrf2), an antioxidative transcription factor, in BDE-47-induced inflammatory responses in the cells. Treatment of HTR-8/SVneo cells with 5, 10, 15, and 20 μM BDE-47 for 24 h increased intracellular glutathione (GSH) levels compared to solvent control. Treatment of HTR-8/SVneo cells with 20 μM BDE-47 for 24 h induced the antioxidant response element (ARE) activity, indicating Nrf2 transactivation by BDE-47 treatment, and resulted in differential expression of redox-sensitive genes compared to solvent control. Pretreatment with tert-butyl hydroquinone (tBHQ) or sulforaphane, known Nrf2 inducers, reduced BDE-47-stimulated IL-6 release with increased ARE reporter activity, reduced nuclear factor kappa B (NF-κB) reporter activity, increased GSH production, and stimulated expression of antioxidant genes compared to non-Nrf2 inducer pretreated groups, suggesting that Nrf2 may play a protective role against BDE-47-mediated inflammatory responses in HTR-8/SVneo cells. These results suggest that Nrf2 activation significantly attenuated BDE-47-induced IL-6 release by augmentation of cellular antioxidative system via upregulation of Nrf2 signaling pathways, and that Nrf2 induction may be a potential therapeutic target to reduce adverse pregnancy outcomes associated with toxicant-induced oxidative stress and inflammation. - Highlights: • BDE-47 stimulated ARE reporter activity and GSH production. • BDE-47 resulted in differential

  12. Benzene degradation in a denitrifying biofilm reactor

    NARCIS (Netherlands)

    Waals, van der Marcelle J.; Atashgahi, Siavash; Rocha, da Ulisses Nunes; Zaan, van der Bas M.; Smidt, Hauke; Gerritse, Jan

    2017-01-01

    Benzene is an aromatic compound and harmful for the environment. Biodegradation of benzene can reduce the toxicological risk after accidental or controlled release of this chemical in the environment. In this study, we further characterized an anaerobic continuous biofilm culture grown for more

  13. SYNTHESIS OF 4’-ALLYLBENZO-3N-CROWN-N ETHERS AND THEIR MASS SPECTRA COMPARED WITH BENZO-3N-CROWN-N ETHERS

    OpenAIRE

    Anwar, Chairil

    2008-01-01

    Synthesis of 4’allylbenzo-3n-crown-n ethers was carried out by reacting demethylated eugenol with α,ω-dichloro-oligoethylene glycols in 1-butanol under basic condition. The mass spectra of 4’allylbenzo-3n-crown-n and benzo-3n-crown-n were investigated by mass spectrometry using electron impact under 70 eV of electron bombardment as ionisation method. The difference between the group of compounds is only the present of allyl moiety as a side chain at the other side of benzene ring. The first g...

  14. Benzene and lymphohematopoietic malignancies in humans.

    Science.gov (United States)

    Hayes, R B; Songnian, Y; Dosemeci, M; Linet, M

    2001-08-01

    Quantitative evaluations of benzene-associated risk for cancer have relied primarily on findings from a cohort study of highly exposed U.S. rubber workers. An epidemiologic investigation in China (NCI/CAPM study) extended quantitative evaluations of cancer risk to a broader range of benzene exposures, particularly at lower levels. We review the evidence implicating benzene in the etiology of hematopoietic disorders, clarify methodologic aspects of the NCI/CAPM study, and examine the study in the context of the broader literature on health effects associated with occupational benzene exposure. Quantitative relationships for cancer risk from China and the U.S. show a relatively smooth increase in risk for acute myeloid leukemia and related conditions over a broad dose range of benzene exposure (below 200 ppm-years mostly from the China study and above 200 ppm-years mostly from the U.S. study). Risks of acute myeloid leukemia and other malignant and nonmalignant hematopoietic disorders associated with benzene exposure in China are consistent with other information about benzene exposure, hematotoxicity, and cancer risk, extending evidence for hematopoietic cancer risks to levels substantially lower than had previously been established. Published 2001 Wiley-Liss, Inc.

  15. Free radical scavenger, N-tert-butyl-alfa-phenylnitrone, affects long-term outcome of status epilepticus in immature rats

    Czech Academy of Sciences Publication Activity Database

    Kubová, Hana; Rejchrtová, Jana; Folbergrová, Jaroslava; Mareš, Pavel

    2005-01-01

    Roč. 46, č. S8 (2005), s. 111-112 [Joint Annual Meeting of the American Epilepsy Society and American Clinical Neurophysiology Society. 02.12.2005-06.12.2005, Washington, DC] R&D Projects: GA ČR(CZ) GA304/05/2582 Institutional research plan: CEZ:AV0Z50110509 Keywords : status epilepticus * PBN * rat Subject RIV: ED - Physiology

  16. Novel Process Windows for the safe and continuous synthesis of tert.-butyl peroxypivalate with micro process technology

    NARCIS (Netherlands)

    Illg, T.

    2013-01-01

    Based on the economy of scale, the classical chemical industry uses large scale reactors to increase production output and to decrease the average unit costs. This results in large footprint plants consuming land and a huge amount of resources. This large scale character bears certain risks for the

  17. Trimethylamine N-oxide (TMAO) and tert-butyl alcohol (TBA) at hydrophobic interfaces: insights from molecular dynamics simulations.

    Science.gov (United States)

    Fiore, Andrew; Venkateshwaran, Vasudevan; Garde, Shekhar

    2013-06-25

    TMAO, a potent osmolyte, and TBA, a denaturant, have similar molecular architecture but somewhat different chemistry. We employ extensive molecular dynamics simulations to quantify their behavior at vapor-water and octane-water interfaces. We show that interfacial structure-density and orientation-and their dependence on solution concentration are markedly different for the two molecules. TMAO molecules are moderately surface active and adopt orientations with their N-O vector approximately parallel to the aqueous interface. That is, not all methyl groups of TMAO at the interface point away from the water phase. In contrast, TBA molecules act as molecular amphiphiles, are highly surface active, and, at low concentrations, adopt orientations with their methyl groups pointing away and the C-O vector pointing directly into water. The behavior of TMAO at aqueous interfaces is only weakly dependent on its solution concentration, whereas that of TBA depends strongly on concentration. We show that this concentration dependence arises from their different hydrogen bonding capabilities-TMAO can only accept hydrogen bonds from water, whereas TBA can accept (donate) hydrogen bonds from (to) water or other TBA molecules. The ability to self-associate, particularly visible in TBA molecules in the interfacial layer, allows them to sample a broad range of orientations at higher concentrations. In light of the role of TMAO and TBA in biomolecular stability, our results provide a reference with which to compare their behavior near biological interfaces. Also, given the ubiquity of aqueous interfaces in biology, chemistry, and technology, our results may be useful in the design of interfacially active small molecules with the aim to control their orientations and interactions.

  18. The new 3-(tert-butyl)-1-(2-nitrophenyl)-1H-pyrazol-5-amine: Experimental and computational studies

    Science.gov (United States)

    Cuenú, Fernando; Muñoz-Patiño, Natalia; Torres, John Eduard; Abonia, Rodrigo; Toscano, Rubén A.; Cobo, J.

    2017-11-01

    The molecular and supramolecular structure of the title compound, 3-(tertbutyl)-1-(2-nitrophenyl)-1H-pyrazol-5-amine (2NPz) from the single crystal X-ray diffraction (SC-XRD) and spectroscopic data analysis is reported. The computational analysis of the structure, geometry optimization, vibrational frequencies, nuclear magnetic resonance and UV-Vis is also described and compared with experimental data. Satisfactory theoretical aspects were made for the molecule using density functional theory (DFT), with B3LYP and B3PW91 functionals, and Hartree-Fock (HF), with 6-311++G(d,p) basis set, using GAUSSIAN 09 program package without any constraint on the geometry. With VEDA 4 software, vibrational frequencies were assigned in terms of the potential energy distribution while, with the GaussSum software, the percentage contribution of the frontier orbitals at each transition of the electronic absorption spectrum was established. The obtained results indicated that optimized geometry could well reflect the molecular structural parameters from SC-XRD. Theoretical data obtained for the vibrational analysis and NMR spectra are consistent with experimental data.

  19. Crystal structure of 2-tert-butyl-2,3-dihydro-1H-benzo[c]pyrrol-1-one

    Czech Academy of Sciences Publication Activity Database

    Donkeng Dazie, Joel; Ludvík, Jiří; Fábry, Jan; Eigner, Václav

    2017-01-01

    Roč. 73, č. 8 (2017), s. 1184-1188 ISSN 2056-9890 R&D Projects: GA ČR GA13-21704S; GA MŠk(CZ) LO1603 EU Projects: European Commission(CZ) CZ.2.16/3.1.00/24510 Institutional support: RVO:61388955 ; RVO:68378271 Keywords : crystal structure * aromaticity * heterocyclic compounds Subject RIV: CF - Physical ; Theoretical Chemistry; BM - Solid Matter Physics ; Magnetism (FZU-D) OBOR OECD: Physical chemistry; Condensed matter physics (including formerly solid state physics, supercond.) (FZU-D)

  20. alpha-Phenyl-N-tert-butyl nitrone attenuates methamphetamine-induced depletion of striatal dopamine without altering hyperthermia.

    Science.gov (United States)

    Cappon, G D; Broening, H W; Pu, C; Morford, L; Vorhees, C V

    1996-10-01

    Methamphetamine (MA) administration to adult rats (4 x 10 mg/kg s.c.) induces neurotoxicity predominately characterized by a persistent reduction of neostriatal dopamine (DA) content. Hyperthermia following MA administration potentiates the resulting DA depletion. DA-derived free radicals are postulated to be a mechanism through which MA-induced neurotoxicity is produced. The spin trapping agent PBN reacts with free radicals to form nitroxyl adducts, thereby preventing damaging free radical reactions with cellular substrates. MA with saline pretreatment (Sal-MA) reduced neostriatal DA by 55% (P protection. PBN pretreatment did not alter MA-induced hyperthermia. Thus, PBN does not attenuate MA-induced neurotoxicity by reducing MA-induced hyperthermia. These results support a role for free radicals in the generation of MA-induced dopaminergic neurotoxicity.

  1. Comparison of the effects of tert-butyl hydroperoxide and peroxynitrite on the oxidative damage to isolated beef heart mitochondria

    Czech Academy of Sciences Publication Activity Database

    Kohutiar, Matej; Ivica, Josko; Vytášek, R.; Skoumalová, A.; Illner, Jan; Šantorová, P.; Wilhelm, Jiří

    2016-01-01

    Roč. 65, č. 4 (2016), s. 617-626 ISSN 0862-8408 R&D Projects: GA ČR(CZ) GAP303/11/0298 Institutional support: RVO:67985823 Keywords : oxidative stress * free radicals * lipid peroxidation * lipofuscinlike pigments * nitrotyrosine Subject RIV: ED - Physiology Impact factor: 1.461, year: 2016

  2. Exogenous ether lipids predominantly target mitochondria.

    Directory of Open Access Journals (Sweden)

    Lars Kuerschner

    Full Text Available Ether lipids are ubiquitous constituents of cellular membranes with no discrete cell biological function assigned yet. Using fluorescent polyene-ether lipids we analyzed their intracellular distribution in living cells by microscopy. Mitochondria and the endoplasmic reticulum accumulated high amounts of ether-phosphatidylcholine and ether-phosphatidylethanolamine. Both lipids were specifically labeled using the corresponding lyso-ether lipids, which we established as supreme precursors for lipid tagging. Polyfosine, a fluorescent analogue of the anti-neoplastic ether lipid edelfosine, accumulated to mitochondria and induced morphological changes and cellular apoptosis. These data indicate that edelfosine could exert its pro-apoptotic power by targeting and damaging mitochondria and thereby inducing cellular apoptosis. In general, this study implies an important role of mitochondria in ether lipid metabolism and intracellular ether lipid trafficking.

  3. Statistical evaluation of variables affecting occurrence of hydrocarbons in aquifers used for public supply, California

    Science.gov (United States)

    Landon, Matthew K.; Burton, Carmen A.; Davis, Tracy A.; Belitz, Kenneth; Johnson, Tyler D.

    2014-01-01

    The variables affecting the occurrence of hydrocarbons in aquifers used for public supply in California were assessed based on statistical evaluation of three large statewide datasets; gasoline oxygenates also were analyzed for comparison with hydrocarbons. Benzene is the most frequently detected (1.7%) compound among 17 hydrocarbons analyzed at generally low concentrations (median detected concentration 0.024 μg/l) in groundwater used for public supply in California; methyl tert-butyl ether (MTBE) is the most frequently detected (5.8%) compound among seven oxygenates analyzed (median detected concentration 0.1 μg/l). At aquifer depths used for public supply, hydrocarbons and MTBE rarely co-occur and are generally related to different variables; in shallower groundwater, co-occurrence is more frequent and there are similar relations to the density or proximity of potential sources. Benzene concentrations are most strongly correlated with reducing conditions, regardless of groundwater age and depth. Multiple lines of evidence indicate that benzene and other hydrocarbons detected in old, deep, and/or brackish groundwater result from geogenic sources of oil and gas. However, in recently recharged (since ~1950), generally shallower groundwater, higher concentrations and detection frequencies of benzene and hydrocarbons were associated with a greater proportion of commercial land use surrounding the well, likely reflecting effects of anthropogenic sources, particularly in combination with reducing conditions.

  4. Radiocarbon dating methods using benzene liquid scintillation

    International Nuclear Information System (INIS)

    Togashi, Shigeko; Matsumoto, Eiji

    1983-01-01

    The radiocarbon dating method using benzene liquid scintillation is reported in detail. The results of measurement of NBS oxalic acid agree with the recommended value, indicating that isotopic fractionation during benzene synthesis can be negligible. Ten samples which have been already measured by gas counter are dated by benzene liquid scintillation. There is no significant difference in age for the same sample between benzene liquid scintillation and gas counters. It is shown that quenching has to be corrected for the young sample. Memory effect in stainless steel reaction vessel can be removed by using an exchangeable inner vessel and by baking it in the air. Using this method, the oldest age that can be measured with 2.3 g carbon is 40,000 years B.P. (author)

  5. Aromaticity of benzene in condensed phases. A case of a benzene-water system

    Science.gov (United States)

    Zborowski, Krzysztof K.

    2014-05-01

    A theoretical Density Functional Theory study was performed for a benzene molecule in water cages. Two DFT functionals (B3LYP and BLYP) were employed. The optimized geometries of the studied clusters were used to calculate the aromaticity of benzene in a condensed phase using the aromaticity indices: HOMA, NICS, PDI, and H. The results were compared with aromaticity of a single benzene molecule in the gas phase and in the solvent environment provided by the PCM continuum model. It is argued that high aromaticity of benzene in the gas phase is retained in the water environment.

  6. The simple ethers of glycerin

    International Nuclear Information System (INIS)

    Kimsanov, B.Kh.; Karimov, M.B.

    1998-01-01

    From glycerin derivatives the considerable interest is present simple ethers because many of them are biological active and found wide practical using as an effect drugs, inters for thin organic synthesis, vehicle for injections, regulators of plants growth, reagents, components for perfumery-cosmetic goods and etc

  7. Cation or Solvent-Induced Supermolecular Phthalocyanine Formation: Crown Ether Substituted Phthalocyanines.

    Science.gov (United States)

    1987-06-01

    spectra were obtained with a Varian SF330 spectrofluorimeter with appropriate filters to eliminate scattered light. Fluorescence quantum yields were...initiator. Recrystallisation from ethanol gave colorless plates in 51Z yield . Anal.calcd. for C1 4 Hi 8 Br 2 O5 : C,39.5; H,4.3. Found: C, 39.6; H,4.3Z. 1 H...olive-green product was soxhlet extracted with diethyl ether for 3 days. Benzene recrystallisation provided 2.02g (31Z) of colorless small needles

  8. Radiolysis of Aqueous Benzene Solutions

    Energy Technology Data Exchange (ETDEWEB)

    Christensen, H

    1964-05-15

    Aerated and deaerated aqueous solutions of benzene have been irradiated with {sup 60}Co {gamma}-rays. The products of radiolysis in deaerated, unbuffered or acid, solutions were phenol, biphenyl, hydrogen and in acid solutions also hydrogen peroxide with the following yields: G(phenol) = 0. 37 (0. 37), G(biphenyl) = 1.3 (1.7), G(H{sub 2}) = 0.44 (0. 43) and G(H{sub 2}O{sub 2}) = 0 (0.60), the figures in brackets giving the results for acid solutions. The results are shown to agree with the conclusion that k(e{sup -}{sub aq} + H{sub 2}O{sub 2}) >> k(H + H{sub 2}O{sub 2}). Furthermore, the results indicate that a competition takes place between the reactions: 2 C{sub 6}H{sub 6}OH {center_dot} -> dimer -> biphenyl. C{sub 6}H{sub 7} {center_dot} + C{sub 6}H{sub 6}OH {center_dot} -> dimer -> biphenyl. The yields in aerated, unbuffered or acid, solutions were: G(phenol) = 2.1 (2.3), G(biphenyl) = 0 (0), and G(H{sub 2}O{sub 2}) = 2.2 (3.1), the figures in brackets being valid for acid solutions. The ratio k(H + C{sub 6}H{sub 6})/k(H + O{sub 2}) was 1.4x10{sup -2}. The results indicate that peroxides, or more probably hydroperoxides, take part in the reactions. After the addition of Fe{sup 2+} or Fe{sup 3+} to aerated acid solutions G(phenol) was increased to 6.6 and 3.4 respectively. Oxygen was consumed more rapidly in the presence of Fe. Reaction mechanisms are discussed.

  9. Poly (ether ether ketone) membranes for fuel cells

    International Nuclear Information System (INIS)

    Marrero, Jacqueline C.; Gomes, Ailton de S.; Filho, Jose C.D.; Hui, Wang S.; Oliveira, Vivianna S. de

    2015-01-01

    Polymeric membranes were developed using a SPEEK polymer matrix (sulphonated poly (ether ether ketone)), containing hygroscopic particles of zirconia (Zr) (incorporated by sol-gel method), for use as electrolyte membranes in fuel cells. SPEEK with different sulfonation degrees were used: 63 and 86%. The thermal analysis (TGA and DSC) was carried out to characterize the membranes and electrochemical impedance spectroscopy (EIS) was carried out to evaluating the proton conductivity of the membranes. Additional analysis were underway in order to characterize these membranes, which include: X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) in order to evaluate the influence of zirconia and sulfonation degree on the properties of the membranes. (author)

  10. Hydrogen storage by functionalised Poly(ether ether ketone)

    Energy Technology Data Exchange (ETDEWEB)

    Pedicini, R.; Giacoppo, G.; Carbone, A.; Passalacqua, E. [CNR-ITAE, Messina (Italy). Inst. for Advanced Energy Technologies

    2010-07-01

    In this work a functionalised polymer was studied as potential material for hydrogen storage in solid state. A Poly(ether ether ketone) (PEEK) matrix was modified by a manganese oxide in situ formation. Here we report the functionalisation process and the preliminary results on hydrogen storage capability of the synthesised polymer. The polymer was characterized by Scanning Electron Microscopy, X-ray diffraction, Transmission Electron Microscopy and Gravimetric Hydrogen Adsorption measurements. In the functionalised PEEK, morphological changes occur as a function of oxide precursor concentration and reaction time. Promising results by gravimetric measurements were obtained with a hydrogen sorption of 0.24%wt/wt at 50 C and 60 bar, moreover, reversibility hydrogen adsorption and desorption in a wide range of both temperature and pressure was confirmed. (orig.)

  11. Biaxial deformation behaviour of poly-ether-ether-ketone

    Science.gov (United States)

    Turner, Josh; Menary, Gary; Martin, Peter

    2018-05-01

    The biaxial tensile properties of thin poly-ether-ether-ketone (PEEK) films are presented. Investigation into the biaxial mechanical behaviour of PEEK films will provide a preliminary insight into the anticipated stress/strain response, and potential suitability, to the possible fabrication of thin walled parts through stretch blow moulding and thermoforming processes - with the multi-axial state of strain imposed onto the heated thermoplastic sheet representative of the expected strain history experienced during these material forming processes. Following identification of the prospective forming temperature window, the biaxial mechanical behaviour of the material is characterized under differing modes of deformation, at a nominal strain rate of 1 s-1. The temperature dependence is outlined within - with an appreciable increase in flow behaviour correlated with specimen temperature exceeding its glass transition temperature (Tg).

  12. Photosynthesis involvement in the mechanism of action of diphenyl ether herbicides.

    Science.gov (United States)

    Ensminger, M P; Hess, F D

    1985-05-01

    Photosynthesis is not required for the toxicity of diphenyl ether herbicides, nor are chloroplast thylakoids the primary site of diphenyl ether herbicide activity. Isolated spinach (Spinacia oleracea L.) chloroplast fragments produced malonyl dialdehyde, indicating lipid peroxidation, when paraquat (1,1'-dimethyl-4,4'-bipyridinium ion) or diuron [3-(3,4-dichlorophenyl)-1,1-dimethylurea] were added to the medium, but no malonyl dialdehyde was produced when chloroplast fragments were treated with the methyl ester of acifluorfen (methyl 5-[2-chloro-4-(trifluoromethyl)phenoxy]-2-nitrobenzoic acid), oxyfluorfen [2-chloro-1-(3-ethoxy-4-nitrophenoxy)-4-(trifluoromethyl)benzene], or MC15608 (methyl 5-[2-chloro-4-(trifluoromethyl)phenoxy]-2-chlorobenzoate). In most cases the toxicity of acifluorfen-methyl, oxyfluorfen, or MC15608 to the unicellular green alga Chlamydomonas eugametos (Moewus) did not decrease after simultaneous treatment with diuron. However, diuron significantly reduced cell death after paraquat treatment at all but the highest paraquat concentration tested (0.1 millimolar). These data indicate electron transport of photosynthesis is not serving the same function for diphenyl ether herbicides as for paraquat. Additional evidence for differential action of paraquat was obtained from the superoxide scavenger copper penicillamine (copper complex of 2-amino-3-mercapto-3-methylbutanoic acid). Copper penicillamine eliminated paraquat toxicity in cucumber (Cucumis sativus L.) cotyledons but did not reduce diphenyl ether herbicide toxicity.

  13. Photosynthesis Involvement in the Mechanism of Action of Diphenyl Ether Herbicides 1

    Science.gov (United States)

    Ensminger, Michael P.; Hess, F. Dan

    1985-01-01

    Photosynthesis is not required for the toxicity of diphenyl ether herbicides, nor are chloroplast thylakoids the primary site of diphenyl ether herbicide activity. Isolated spinach (Spinacia oleracea L.) chloroplast fragments produced malonyl dialdehyde, indicating lipid peroxidation, when paraquat (1,1′-dimethyl-4,4′-bipyridinium ion) or diuron [3-(3,4-dichlorophenyl)-1,1-dimethylurea] were added to the medium, but no malonyl dialdehyde was produced when chloroplast fragments were treated with the methyl ester of acifluorfen (methyl 5-[2-chloro-4-(trifluoromethyl)phenoxy]-2-nitrobenzoic acid), oxyfluorfen [2-chloro-1-(3-ethoxy-4-nitrophenoxy)-4-(trifluoromethyl)benzene], or MC15608 (methyl 5-[2-chloro-4-(trifluoromethyl)phenoxy]-2-chlorobenzoate). In most cases the toxicity of acifluorfen-methyl, oxyfluorfen, or MC15608 to the unicellular green alga Chlamydomonas eugametos (Moewus) did not decrease after simultaneous treatment with diuron. However, diuron significantly reduced cell death after paraquat treatment at all but the highest paraquat concentration tested (0.1 millimolar). These data indicate electron transport of photosynthesis is not serving the same function for diphenyl ether herbicides as for paraquat. Additional evidence for differential action of paraquat was obtained from the superoxide scavenger copper penicillamine (copper complex of 2-amino-3-mercapto-3-methylbutanoic acid). Copper penicillamine eliminated paraquat toxicity in cucumber (Cucumis sativus L.) cotyledons but did not reduce diphenyl ether herbicide toxicity. PMID:16664206

  14. An inverse modeling approach to estimate groundwater flow and transport model parameters at a research site at Vandenberg AFB, CA

    Science.gov (United States)

    Rasa, E.; Foglia, L.; Mackay, D. M.; Ginn, T. R.; Scow, K. M.

    2009-12-01

    A numerical groundwater fate and transport model was developed for analyses of data from field experiments evaluating the impacts of ethanol on the natural attenuation of benzene, toluene, ethylbenzene, and xylenes (BTEX) and methyl tert-butyl ether (MTBE) at Vandenberg Air Force Base, Site 60. We used the U.S. Geological Survey (USGS) groundwater flow (MODFLOW2000) and transport (MT3DMS) models in conjunction with the USGS universal inverse modeling code (UCODE) to jointly determine flow and transport parameters using bromide tracer data from multiple experiments in the same location. The key flow and transport parameters include hydraulic conductivity of aquifer and aquitard layers, porosity, and transverse and longitudinal dispersivity. Aquifer and aquitard layers were assumed homogenous in this study. Therefore, the calibration parameters were not spatially variable within each layer. A total of 162 monitoring wells in seven transects perpendicular to the mean flow direction were monitored over the course of ten months, resulting in 1,766 bromide concentration data points and 149 head values used as observations for the inverse modeling. The results showed the significance of the concentration observation data in predicting the flow model parameters and indicated the sensitivity of the hydraulic conductivity of different zones in the aquifer including the excavated former contaminant zone. The model has already been used to evaluate alternative designs for further experiments on in situ bioremediation of the tert-butyl alcohol (TBA) plume remaining at the site. We describe the recent applications of the model and future work, including adding reaction submodels to the calibrated flow model.

  15. MTBE IN SITU BIODEGRADATION IN BIONETS USING ISOLITE, PM1, SLOW RELEASING OXYGEN AND AIR IN INDIAN COUNTRY

    Science.gov (United States)

    Methyl tert-Butyl Ether (MTBE), a gasoline additive, is a persistent, foul tasting chemical and more mobile in ground water than BTEX. Our objective was to determine if biologically active in situ Bionets could bioremediate MTBE. Seven Bionets, most containing 3 fractures each,...

  16. BTEX MTBE BIOREMEDIATION: BIONETS CONTAINING ISOLITE, PM1, SOLID OXYGEN SOURCE

    Science.gov (United States)

    Methyl tert-Butyl Ether (MTBE), a gasoline additive, is a persistent and foul tasting contaminate that is more mobile in ground water than BTEX . It, along with BTEX, is turning up at many American crossroads. This study's objective was to determine if biologically active in sit...

  17. 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...

  18. 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...

  19. 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...

  20. Conversion of methanol and isobutanol to MTBE

    CSIR Research Space (South Africa)

    Nicolaides, CP

    1993-09-24

    Full Text Available Over the resin catalyst Amberlyst 15, and under our reaction conditions, the yield of MTBE (methyl tert-butyl ether), from the reaction of methanol and isobutene, is at a maximum in the temperature rang of 40-60-degrees-C. Slightly higher...

  1. Volume 10 No. 8 August 2010 3015 CHANGES IN ...

    African Journals Online (AJOL)

    user

    2010-08-08

    Aug 8, 2010 ... Orange-fleshed sweet potatoes can, therefore, help alleviate vitamin A deficiency ... work was double- distilled. Moisture content ... methyl-tert-butyl- ether (1:1, v/v) in a flask and filtered through a 0.45 mporesizemembranefilter.

  2. CONTROLLED, SHORT-TERM DERMAL AND INHALATION EXPOSURE TO MTBE AND DIBROMOCHLOROMETHANE

    Science.gov (United States)

    The oxygenate methyl tert-butyl ether (MTBE) has been added to gasoline to meet national ambient air quality standards in those parts of the US that are non-compliant for carbon monoxide. Although MTBE has provided important health benefits in terms of reduced hazardous air po...

  3. Fenton-driven regeneration of MTBE-spent granular activated carbon - Effects of particle size and Iron Amendment Procedures

    Science.gov (United States)

    Fenton-driven regeneration of spent granular activated carbon (GAC) is a technology being developed to regenerate organic contaminant-spent GAC. Here, the effect of GAC particle size (>2 mm to <0.35 mm) on Fenton-driven oxidation of methyl tert-butyl ether (MTBE)-spent GAC was ev...

  4. 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...

  5. Effects on temperature and acidic pre-treatment on Fenton-driven oxidation of MTBE-spent granular activated carbon

    Science.gov (United States)

    Temperature-dependent mechanisms in the Fenton-driven chemical oxidation of methyl tert-butyl ether (MTBE)-spent granular activated carbon (GAC) was investigated. Prior to iron (Fe) amendment to the GAC, acid-treatment altered the surface chemistry of the GAC and lowered the p...

  6. Effects of Temperature and Acidic Pre-Treatment on Fenton-Driven Oxidation of MTBE-Spent Granular Activated Carbon

    Science.gov (United States)

    Temperature-dependent mechanisms in the Fenton-driven chemical oxidation of methyl tert-butyl ether (MTBE)-spent granular activated carbon (GAC) was investigated. Prior to iron (Fe) amendment to the GAC, acid-treatment altered the surface chemistry of the GAC and lowered the pH ...

  7. USE OF MEMBRANE BIOREACTOR FOR BIODEGRADATION OF MTBE IN CONTAMINATED WATER1

    Science.gov (United States)

    An ultrafiltration membrane bioreactor was evaluated for biodegradation of methyl tert-butyl ether (MTBE) in contaminated water. The system was fed 5 mg/L MTBE in granular activated carbon (GAC) treated Cincinnati tap water containing ample buffer and nutrients. Within 120...

  8. The industrial production of dimethyl carbonate from methanol and carbon dioxide

    NARCIS (Netherlands)

    De Groot, Frank F T; Lammerink, Roy R G J; Heidemann, Casper; Van Der Werff, Michiel P M; Garcia, Taiga Cafiero; Van Der Ham, Louis A G J; Van Den Berg, Henk

    2014-01-01

    This work discusses the design of a dimethyl carbonate (DMC) production plant based on methanol and CO2 as feed materials, which are a cheap and environment-friendly feedstock. DMC is a good alternative for methyl-tert-butyl ether (MTBE) as a fuel oxygenating agent, due to its low toxicity and fast

  9. 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

  10. Quantifying residues from postharvest fumigation of almonds and walnuts with propylene oxide

    Science.gov (United States)

    A novel analytical approach, involving solvent extraction with methyl tert-butyl ether (MTBE) followed by gas chromatography (GC), was developed to quantify residues that result from the postharvest fumigation of almonds and walnuts with propylene oxide (PPO). Verification and quantification of PPO,...

  11. Analysis of Fluorotelomer Alcohols in Soils: Optimization of Extraction and Chromatography

    Science.gov (United States)

    This article describes the development of an analytical method for the determination of fluorotelomer alcohols (FTOHs) in soil. The sensitive and selective determination of the telomer alcohols was performed by extraction with mthyl tert-butyl ether (MTBE) and analysis of the ext...

  12. An on-line normal-phase high performance liquid chromatography method for the rapid detection of radical scavengers in non-polar food matrixes

    NARCIS (Netherlands)

    Zhang, Q.; Klift, van der E.J.C.; Janssen, H.G.; Beek, van T.A.

    2009-01-01

    An on-line method for the rapid pinpointing of radical scavengers in non-polar mixtures like vegetable oils was developed. To avoid problems with dissolving the sample, normal-phase chromatography on bare silica gel was used with mixtures of hexane and methyl tert-butyl ether as the eluent. The high

  13. 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...

  14. Particle Size Effects on Fenton Regeneration of MTBE-spent Activated Carbon

    Science.gov (United States)

    Fenton-driven regeneration of spent granular activated carbon (GAC) is a developing technology that may reduce water treatment costs. In this study, the effect of GAC particle size on Fenton-driven oxidation of methyl tert-butyl ether (MTBE)-spent GAC was evaluated. The GAC was...

  15. Iron Amendment and Fenton Oxidation of MTBE-Spent Granular Activated Carbon

    Science.gov (United States)

    Fenton-driven regeneration of Methyl tert-butyl ether (MTBE)-spent granular activated carbon (GAC) involves Fe amendment to the GAC to catalyze H2O2 reactions and to enhance the rate of MTBE oxidation and GAC regeneration. Four forms of iron (ferric sulfate, ferric chloride, fer...

  16. Fenton-like Degradation of MTBE: Effects of Iron Counter Anion and Radical Scavengers

    Science.gov (United States)

    Fenton-driven oxidation of Methyl tert-butyl ether (MTBE) (0.11-0.16 mM) in batch reactors containing ferric iron (5 mM), hydrogen peroxide (H2O2) (6 mM) (pH=3) was performed to investigate MTBE transformation mechanisms. Independent variables included the form of iron (Fe) (Fe2(...

  17. Fenton-Driven Regeneration of MTBE-spent Granular Activated Carbon

    Science.gov (United States)

    Fenton-driven regeneration of Methyl tert-butyl ether (MTBE)-spent granular activated carbon (GAC) involves the combined, synergistic use of two treatment technologies: adsorption of organic chemicals onto activated carbon and Fenton-driven oxidation regeneration of the spent-GAC...

  18. Fenton-driven regeneration of MTBE-spent granular activated carbon - Effects of particle size and Iron Amendment Procedures

    Science.gov (United States)

    Fenton-driven regeneration of spent granular activated carbon (GAC) is a technology being developed to regenerate organic contaminant-spent GAC. Here, the effect of GAC particle size (>2 mm to Fenton-driven oxidation of methyl tert-butyl ether (MTBE)-spent GAC was ev...

  19. Benzene monitoring at CPPI service stations

    International Nuclear Information System (INIS)

    Davis, C.S.

    1996-01-01

    A study was conducted in which ambient airborne concentration levels of benzene were measured at a representative set of gasoline service stations in Toronto and Vancouver. Benzene is considered to be toxic under the Canadian Environmental Protection Act (CEPA). It is a component in gasoline (0.1 to 4.7 per cent by volume) and is present in vehicle evaporative and exhaust emissions. Measurements were made every 18 days at each station for one year. The objective of the study was to assess the ambient and employee exposure levels of benzene at service stations and to determine whether the levels were typical of those published in the literature. In a 1986 PACE (Petroleum Association for Conservation of the Canadian Environment) survey of exposure to gasoline hydrocarbon vapours at Canadian service stations, airborne benzene concentration data was inconsistent with similar ambient and personal exposure data in the international literature. It was concluded that both the mean ambient benzene concentration and the personal exposure level measurements in this study were generally lower than similar measurements made in other countries. The same observation was made with respect to ambient and personal exposure levels measured in this study vis-a-vis those measured during the PACE study conducted in 1985/86. . 31 refs., 24 tabs., 5 figs

  20. Sulfonated polyphenyl ether by electropolymerization

    International Nuclear Information System (INIS)

    Hou Hongying; Vacandio, Florence; Di Vona, Maria Luisa; Knauth, Philippe

    2012-01-01

    Highlights: ► Sulfonated polyphenyl ether was for the first time electropolymerized. ► This technique allows the economical preparation of ionomeric membranes for electrochemical energy technologies. ► The mechanism of electropolymerization was discussed in detail. - Abstract: Electropolymerization of sulfonated phenol was for the first time achieved and studied by cyclic voltammetry (CV) and chronoamperometry on stainless steel substrates. The obtained sulfonated polyphenyl ether was characterized in terms of impedance spectroscopy, nuclear magnetic resonance (NMR), energy dispersive X-ray analysis (EDX), X-ray diffraction (XRD) and Fourier-Transform Infrared (FTIR) spectroscopy. Dense films of micrometer thickness can be obtained; the proton conductivity is about 3 mS/cm at room temperature.

  1. Used motor oil as a source of MTBE, TAME, and BTEX to ground water

    Science.gov (United States)

    Baker, R.J.; Best, E.W.; Baehr, A.L.

    2002-01-01

    Methyl tert-butyl ether (MTBE), the widely used gasoline oxygenate, has been identified as a common ground water contaminant, and BTEX compounds (benzene, toluene, ethylbenzene, and xylenes) have long been associated with gasoline spills. Because not all instances of ground water contamination by MTBE and BTEX can be attributed to spills or leaking storage tanks, other potential sources need to be considered. In this study, used motor oil was investigated as a potential source of these contaminants. MTBE in oil was measured directly by methanol extraction and gas chromatography using a flame ionization detector (GC/FID). Water was equilibrated with oil samples and analyzed for MTBE, BTEX, and the oxygenate tert-amyl methyl ether (TAME) by purge-and-trap concentration followed by GC/FID analysis. Raoult's law was used to calculate oil-phase concentrations of MTBE, BTEX, and TAME from aqueous-phase concentrations. MTBE, TAME, and BTEX were not detected in any of five new motor oil samples, whereas these compounds were found at significant concentrations in all six samples of the used motor oil tested for MTBE and all four samples tested for TAME and BTEX. MTBE concentrations in used motor oil were on the order of 100 mg/L. TAME concentrations ranged from 2.2 to 87 mg/L. Concentrations of benzene were 29 to 66 mg/L, but those of other BTEX compounds were higher, typically 500 to 2000 mg/L.

  2. Actinide/crown ether chemistry

    International Nuclear Information System (INIS)

    Benning, M.M.

    1988-01-01

    A structural survey of actinide/crown ether compounds was conducted in order to investigate the solid state chemistry of these complexes. Several parameters - the metal size, crown type, counterion, solvent systems and reaction and crystallization conditions - were varied to correlate their importance in complexation. Under atmospheric conditions, two types of complexes were isolated, those containing only hydrogen-bonded crown interactions and instances where the crown interacts directly with the metal center. In both cases, water seems to play a very important role. When coordinated to the metal, water molecules exhibit the necessary donor properties required for the formation of hydrogen-bonded contacts. The water molecules also provide fierce competition with the crown ethers for metal-binding sites and in most cases prohibit the formation of complexes in which direct metal-ligand association exists. The results of this study indicate that direct interaction between the metal atoms and the crown ethers, in the presence of water, can only occur with polyether conformations which limit the steric replusions within the metal coordination sphere

  3. Dehydrogenation of benzene on Pt(111) surface

    Science.gov (United States)

    Gao, W.; Zheng, W. T.; Jiang, Q.

    2008-10-01

    The dehydrogenation of benzene on Pt(111) surface is studied by ab initio density functional theory. The minimum energy pathways for benzene dehydrogenation are found with the nudge elastic band method including several factors of the associated barriers, reactive energies, intermediates, and transient states. The results show that there are two possible parallel minimum energy pathways on the Pt(111) surface. Moreover, the tilting angle of the H atom in benzene can be taken as an index for the actual barrier of dehydrogenation. In addition, the properties of dehydrogenation radicals on the Pt(111) surface are explored through their adsorption energy, adsorption geometry, and electronic structure on the surface. The vibrational frequencies of the dehydrogenation radicals derived from the calculations are in agreement with literature data.

  4. Polyfunctional catalyst for processiing benzene fractions

    Energy Technology Data Exchange (ETDEWEB)

    G. Byakov; B.D. Zubitskii; B.G. Tryasunov; I.Ya. Petrov [Kuznetsk Basin State Technical University, Kemerovo (Russian Federation)

    2009-05-15

    A by-product of the coke industry is a raw benzene fraction benzene- 1 which may serve as for catalytic processes. The paper reports a study on the influence of the composition and temperatures on the activity and selectivity of NiO-V{sub 2}O{sub 6}-MoO{sub 3}/{gamma}-Al{sub 2}O{sub 3} catalysts and the corresponding binary and tertiary subsystems are studied by a pulse method in model reactions; the hydrodealkylating of toluene and the hydrodesulfurizing of thioprhene. The optimal catalyst composition is established. The new catalyst is compared with industrial catalysts.

  5. Intrinsic bioremediation of a BTEX and MTBE plume under mixed aerobic/denitrifying conditions

    International Nuclear Information System (INIS)

    Borden, R.C.; Daniel, R.A.

    1995-01-01

    A shallow Coastal Plain aquifer in rural Sampson Country, North Carolina, has been contaminated with petroleum hydrocarbon from a leaking underground storage tank containing gasoline.An extensive field characterization has been performed to define the horizontal and vertical distribution of soluble gasoline components and indicator parameters. A plume of dissolved methyl tert-butyl ether (MTBE) and the aromatic hydrocarbons benzene, toluene, ethylbenzene, and xylene isomers (BTEX) is present in the aquifer and has migrated over 600 ft from the source area. Background dissolved oxygen concentrations range from 7 to 8 mg/L, and nitrate concentrations range from 5 to 22 mg/L as N due to extensive fertilization of fields surrounding the spill. In the center of the BTEX plume, oxygen concentrations decline to less than 1 mg/L while nitrate concentrations remain high. The total mass flux of MTBE and all BTEX components decline with distance downgradient relative to a conservative tracer (chloride). At the source, the total BTEX concentration exceeds 75 mg/L while 130 ft downgradient, total BTEX concentrations are less than 4.9 mg/L, a 15-fold reduction. Toluene and ethylbenzene decline most rapidly followed by m-p-xylene, o-xylene and finally benzene. Biodegradation of TEX appears to be enhanced by the excess nitrate present in the aquifer while benzene biodegradation appears to be due to strictly aerobic processes

  6. Comparative effects of MTBE and ethanol additions into gasoline on exhaust emissions

    Science.gov (United States)

    Song, Chong-Lin; Zhang, Wen-Mei; Pei, Yi-Qiang; Fan, Guo-Liang; Xu, Guan-Peng

    The effects of the additives of ethanol (EA) and methyl tert-butyl ether (MTBE) in various blend ratios into the gasoline fuel on the exhaust emissions and the catalytic conversion efficiencies were investigated in an EFI gasoline engine. The regulated exhaust emissions (CO, THC and NO X) and the unregulated exhaust emissions (benzene, formaldehyde, acetaldehyde, unburned EA and MTBE) before and after the three-way catalytic converter were measured. The experimental results showed that EA brought about generally lower regulated engine-out emissions than MTBE did. But, the comparison of the unregulated engine-out emissions between both additives was different. Concretely, the effect of EA on benzene emission was worse than that of MTBE on the whole, which was a contrast with formaldehyde emission. The difference in the acetaldehyde comparison depended much on the engine operating conditions, especially the engine speed. Both EA and MTBE were identified in the engine exhaust gases only when they were added to the fuel, and their volume fraction increased with blend ratios. The catalytic conversion efficiencies of the regulated emissions for the EA blends were in general lower than those for MTBE blends, especially at the low and high engine speeds. There was little difference in the catalytic conversion efficiencies for both benzene and formaldehyde, while distinct difference for acetaldehyde.

  7. Peer Review Comments on the IRIS Assessment of Benzene

    Science.gov (United States)

    Attachment to IRIS file for benzene, January 19, 2000, RESPONSE TO THE PEER REVIEW COMMENTS, II. Extrapolation of the Benzene Inhalation Unit Risk Estimate to the Oral Route of Exposure (EPA/NCEA-W-0517, July 1999)

  8. Survey of benzene and aromatics in Canadian Gasoline - 1994

    International Nuclear Information System (INIS)

    Tushingham, M.

    1996-01-01

    A comprehensive database of the benzene and aromatics levels of gasoline produced in or imported into Canada during 1994, was presented. Environment Canada conducted a survey that requested refineries and importers to report quarterly on benzene and aromatics levels in gasoline. Benzene, which has been declared toxic by the Canadian Environmental Protection Act, is found in gasoline and is formed during the combustion of the aromatic components of gasoline. It was shown that benzene and aromatics levels differ regionally and seasonally. There are also variations in benzene levels between batches of gasoline produced at any one refinery. This report listed the responses to the benzene/aromatics survey. It also described the analytical procedures used to measure benzene and aromatics levels in gasoline, and provided guidelines for reporting gasoline benzene and total aromatics data. 7 tabs., 21 figs

  9. Computed structure of small benzene clusters

    NARCIS (Netherlands)

    van de Waal, B.W.

    1986-01-01

    The structures of small benzene clusters (C6H6)n, n = 2–7, have been calculated employing potential-energy minimization with respect to molecular translational and rotational coordinates, using exp-6-1 non-bonded atom-atom potential functions. The influence of the adopted point-charge model is

  10. The oxidative conversion of toluene to benzene

    NARCIS (Netherlands)

    Jong, de J.G.; Batist, P.A.

    1971-01-01

    An oxidative reaction is described in which toluene is converted into benzene. The reaction is catalyzed by bismuth uranate. Selectivities up to 70% are obtained if toluene vapor reacts with the catalyst without O (g) being present; the catalyst becomes partially reduced, but is easily reoxidized

  11. 29 CFR 1910.1028 - Benzene.

    Science.gov (United States)

    2010-07-01

    ...) Scope and application. (1) This section applies to all occupational exposures to benzene. Chemical...-general, and paragraph (e)(6) accuracy of monitoring. Engineering and work practice controls shall be used... wholesale customers. Container means any barrel, bottle, can, cylinder, drum, reaction vessel, storage tank...

  12. Recommended sublimation pressure and enthalpy of benzene

    Czech Academy of Sciences Publication Activity Database

    Růžička, K.; Fulem, Michal; Červinka, C.

    2014-01-01

    Roč. 68, Jan (2014), s. 40-47 ISSN 0021-9614 Institutional support: RVO:68378271 Keywords : benzene * vapor pressure * heat capacity * ideal - gas thermodynamic properties * sublimation enthalpy * recommended vapor pressure Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.679, year: 2014

  13. Ion induced polymerization in benzene frozen films

    Energy Technology Data Exchange (ETDEWEB)

    Calcagno, G [Catania Univ. (Italy). Ist. di Fisica; Strazzulla, G [Catania Univ. (Italy). Osservatorio Astrofisico; Fichera, M; Foti, G [Catania Univ. (Italy). Ist. di Radiologia

    1983-07-01

    The cross section of the polymerization process induced by energetic protons colliding with frozen benzene layers has been measured. The results have been described by a simple theory and they show that the process is a volume one occurring along the ion track and interesting all of the crossed layers.

  14. Vacuum ultraviolet photoabsorption spectroscopy of crystalline and amorphous benzene

    DEFF Research Database (Denmark)

    Dawes, Anita; Pascual, Natalia; Hoffmann, Soren V.

    2017-01-01

    We present the first high resolution vacuum ultraviolet photoabsorption study of amorphous benzene with com parisons to annealed crystalline benzene and the gas phase. Vapour deposited benzene layers w ere grow n at 25 K and annealed to 90 K under conditions pertinent to interstellaricy dust grains...

  15. Contrastive Analysis of the Raman Spectra of Polychlorinated Benzene: Hexachlorobenzene and Benzene

    Directory of Open Access Journals (Sweden)

    Zhengjun Zhang

    2011-12-01

    Full Text Available Detection of persistent pollutants such as polychlorinated benzene in environment in trace amounts is challenging, but important. It is more difficult to distinguish homologues and isomers of organic pollutantd when present in trace amounts because of their similar physical and chemical properties. In this work we simulate the Raman spectra of hexachlorobenzene and benzene, and figure out the vibration mode of each main peak. The effect on the Raman spectrum of changing substituents from H to Cl is analyzed to reveal the relations between the Raman spectra of homologues and isomers of polychlorinated benzene, which should be helpful for distinguishing one kind of polychlorinated benzene from its homologues and isomers by surface enhanced Raman scattering.

  16. Benzene in Canadian gasoline : report on the effect of the benzene in gasoline regulations 2002

    Energy Technology Data Exchange (ETDEWEB)

    Guthrie, J. [Environment Canada, Ottawa, ON (Canada); Sabourin, R. [Carleton Univ., Ottawa, ON (Canada); Brunet, E. [Waterloo Univ., ON (Canada)

    2003-11-01

    The response of primary suppliers to Benzene in Gasoline Regulations was reviewed, and a summary of the effects of those regulations on the composition of gasoline in Canada in 2002 was offered. These regulations, effective July 1, 1999, were designed to provide a new approach to control fuel composition. It allowed suppliers, as a basis for compliance, the option to elect to use a yearly pool average. The benzene emission number (BEN) of gasoline was regulated, and a limit imposed on a per-litre limit for benzene at point of sale. The results indicated that reported benzene levels were significantly reduced, while aromatic levels remained practically unchanged from 1994. Since 1998, rural ambient benzene concentrations decreased by more than 32 per cent, while in urban areas, they decreased by 47 per cent over the same period. The regulated requirements for benzene concentration were met by primary suppliers in Canada in 2002 (with one exception), as were BEN levels. A number of instances of non-compliance with laboratory procedures were discovered during independent audits required for those suppliers who elected to be on on a yearly pool average. Corrective action designed to address these issues was implemented. 41 tabs., 24 figs.

  17. Critical properties of some aliphatic symmetrical ethers

    International Nuclear Information System (INIS)

    Nikitin, Eugene D.; Popov, Alexander P.; Bogatishcheva, Nataliya S.

    2014-01-01

    Highlights: • Critical properties of simple aliphatic ethers were measured. • The ethers decompose at near-critical temperatures. • Pulse-heating method with short residence times was used. -- Abstract: The critical temperatures T c and the critical pressures p c of dihexyl, dioctyl, and didecyl ethers have been measured. According to the measurements, the coordinates of the critical points are T c = (665 ± 7) K, p c = (1.44 ± 0.04) MPa for dihexyl ether, T c = (723 ± 7) K, p c = (1.19 ± 0.04) MPa for dioctyl ether, and T c = (768 ± 8) K, p c = (1.03 ± 0.03) MPa for didecyl ether. All the ethers studied degrade chemically at near-critical temperatures. A pulse-heating method applicable to measuring the critical properties of thermally unstable compounds has been used. The times from the beginning of a heating pulse to the moment of reaching the critical temperature were from 0.06 to 0.46 ms. The short residence times provide little decomposition of the substances in the course of the experiments. The critical properties of the ethers investigated in this work have been discussed together with those of methyl to butyl ethers. The experimental critical constants of the ethers have been compared with those estimated by the group-contribution methods of Wilson and Jasperson and Marrero and Gani. The Wilson/Jasperson method provides a better estimation of the critical temperatures and pressures of simple aliphatic ethers in comparison with the Marrero/Gani method if reliable normal boiling temperatures are used in the method of Wilson and Jasperson

  18. Comparison of Properties among Dendritic and Hyperbranched Poly(ether ether ketones and Linear Poly(ether ketones

    Directory of Open Access Journals (Sweden)

    Atsushi Morikawa

    2016-02-01

    Full Text Available Poly(ether ether ketone dendrimers and hyperbranched polymers were prepared from 3,5-dimethoxy-4′-(4-fluorobenzoyldiphenyl ether and 3,5-dihydroxy-4′-(4-fluorobenzoyldiphenyl ether through aromatic nucleophilic substitution reactions. 1-(tert-Butyldimethylsiloxy-3,5-bis(4-fluorobenzoylbenzene was polycondensed with bisphenols, followed by cleavage of the protective group to form linear poly(ether ketones having the same hydroxyl groups in the side chains as the chain ends of the dendrimer and hyperbranched polymers. Their properties, such as solubilities, reduced viscosities, and thermal properties, were compared with one another. Similar comparisons were also carried out among the corresponding methoxy group polymers, and the size of the molecules was shown to affect the properties.

  19. Numerical analysis of spray characteristics of dimethyl ether and diethyl ether fuel

    International Nuclear Information System (INIS)

    Mohan, Balaji; Yang, Wenming; Yu, Wenbin; Tay, Kun Lin

    2017-01-01

    Highlights: • Thermo-physical properties of liquid DME and DEE are reported. • Ether fuels tend to cavitate higher compared to that of diesel fuel. • Spray tip penetration and SMD are found to be lesser for ether fuels. • Ether fuels shows excellent atomization behavior. - Abstract: In this work, the spray characteristics of ether fuels such as dimethyl ether (DME) and diethyl ether (DEE) have been numerically investigated using KIVA-4 CFD code. A new hybrid spray model developed by coupling the standard KHRT model to cavitation sub model was used. The detailed thermo-physical properties of ether fuels have been predicted and validated with experimental results available from literature. The cavitation inception inside the injector nozzle hole has been studied for ether fuels in comparison with diesel fuel. It was found that ether fuels cavitates higher compared to that of conventional diesel fuel because of its low viscosity. The spray tip penetration of diesel fuel was longer than that of ether fuels due to high viscosity and density of diesel fuel. Ether fuels characterized by low Ohnesorge number and high Reynolds number showed better atomization behavior compared to that of the diesel fuel.

  20. Unitary information ether and its possible applications

    International Nuclear Information System (INIS)

    Horodecki, R.

    1991-01-01

    The idea of information ether as the unitary information field is developed. It rests on the assumption that the notion of information is a fundamental category in the description of reality and that it can be defined independently from the notion of probability itself. It is shown that the information ether provides a deterministic background for the nonlinear wave hypothesis and quantum cybernetics. (orig.)

  1. Indicators of benzene emissions and exposure in Bangkok street

    International Nuclear Information System (INIS)

    Leong, S.T.; Laortanakul, Preecha

    2003-01-01

    Ambient benzene measurements were conducted for the first time at four air monitoring sites in the Bangkok metropolitan region (BMR), from January to December 2001. Analytical results show that the mean benzene concentrations range from 42.4 μg/m 3 at the Din Daeng urban site to 15.1 μg/m 3 at the Chaeng Wattana suburban site. The monitoring results show that at a larger distance from the roadside or a higher level from the street surface, the level of benzene decreases. Analysis of the ambient benzene concentrations was carried out with reference to meteorological influences and traffic density. In traffic analysis, the combined effects of street topography and traffic flows established high impact on the overall benzene concentration in Bangkok. Statistical analysis shows good correlations of blood benzene levels and trans, trans-muconic acid with ambient benzene and demonstrated substantial exposure from traffic

  2. Polyether ether ketone film. Polyether ether ketone film

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, S. (Sumitomo Chemical Co. Ltd., Tokyo (Japan))

    1990-07-05

    The characteristics and the film making process of polyether ether ketone (PEEK) resin, and the characteristics and the applications of PEEK film, are described. PEEK is aromatic polyketone with super thermal resistance. Though it is a crystalline polymer of which the crystallinity is controlled to 48% in a highest degree, it has also amorphous property, thus it shows unique property. The characteristics of PEEK resin are found in thermal resistance, incombusti-bility, transparency, chemical resistance, light resistance and radiation resistance. As for the film making process, casting method by T-die is generally adopted. The general properties of PEEK film are excellent in high thermal resistance, good electrical properties, chemical resistance, hydrolysis resistance, radiation resistance and imcombusti-bility. In the application of PEEK film, new development is expected in following fields; a high performance composite, flexible print substrate with high thermal resistance, insulating tape with thermal resistance, and a general film in the nuclear energy industry. 5 figs., 5 tabs.

  3. High pressure photoinduced ring opening of benzene

    International Nuclear Information System (INIS)

    Ciabini, Lucia; Santoro, Mario; Bini, Roberto; Schettino, Vincenzo

    2002-01-01

    The chemical transformation of crystalline benzene into an amorphous solid (a-C:H) was induced at high pressure by employing laser light of suitable wavelengths. The reaction was forced to occur at 16 GPa, well below the pressure value (23 GPa) where the reaction normally occurs. Different laser sources were used to tune the pumping wavelength into the red wing of the first excited singlet state S 1 ( 1 B 2u ) absorption edge. Here the benzene ring is distorted, presenting a greater flexibility which makes the molecule unstable at high pressure. The selective pumping of the S 1 level, in addition to structural considerations, was of paramount importance to clarify the mechanism of the reaction

  4. Formation of reactive metabolites from benzene

    International Nuclear Information System (INIS)

    Snyder, R.; Jowa, L.; Witz, G.; Kalf, G.; Rushmore, T.

    1986-01-01

    Rat liver mitoplasts were incubated first with [ 3 H]dGTP, to form DNA labeled in G, and then with [ 14 C]benzene. The DNA was isolated and upon isopycnic density gradient centrifugation in CsCl yielded a single fraction of DNA labeled with both [ 3 H] and [ 14 C]. These data are consistent with the covalent binding of one or more metabolites of benzene to DNA. The DNA was enzymatically hydrolyzed to deoxynucleosides and chromatographed to reveal at least seven deoxyguanosine adducts. Further studies with labeled deoxyadenine revealed one adduct on deoxyadenine. [ 3 H]Deoxyguanosine was reacted with [ 14 C]hydroquinone or benzoquinone. The product was characterized using uv, fluorescence, mass and NMR spectroscopy. A proposed structure is described. (orig.)

  5. Environmental exposure to benzene: an update.

    OpenAIRE

    Wallace, L

    1996-01-01

    During the 1990s, several large-scale studies of benzene concentrations in air, food, and blood have added to our knowledge of its environmental occurrence. In general, the new studies have confirmed the earlier findings of the U.S. Environmental Protection Agency Total Exposure Assessment Methodology (TEAM) studies and other large-scale studies in Germany and the Netherlands concerning the levels of exposure and major sources. For example, the new studies found that personal exposures exceed...

  6. PROCESS SIMULATION OF BENZENE SEPARATION COLUMN OF LINEAR ALKYL BENZENE (LABPLANT

    Directory of Open Access Journals (Sweden)

    Zaid A. AbdelRahman

    2013-05-01

    Full Text Available       CHEMCAD process simulator was used for the analysis of existing benzene separation column in LAB plant(Arab Detergent Company/Beiji-Iraq.         Simulated column performance curves were constructed. The variables considered in this study are the thermodynamic model option, top and bottom temperatures, feed temperature, feed composition & reflux ratio. Also simulated columns profiles for the temperature, vapor & liquid flow rates compositions, were constructed. Four different thermodynamic models options (SRK, TSRK, PR, and ESSO were used, affecting the results within 1-25% variation for the most cases.            For Benzene Column (32 real stages, feed stage 14, the simulated results show that bottom temperature above 200 oC the weight fractions of top components, except benzene, increases sharply, where as benzene top weight fraction decreasing sharply. Also, feed temperature above 180 oC  shows same trends. The column profiles remain fairly constant from tray 3 (immediately below condenser to tray 10 (immediately above feed and from tray 15 (immediately below feed to tray 25 (immediately above reboiler. Simulation of the benzene separation column in LAB production plant using CHEMCAD simulator, confirms the real plant operation data. The study gives evidence about a successful simulation with CHEMCAD.

  7. Exposure Evaluation for Benzene, Lead and Noise in Vehicle and Equipment Repair Shops

    Energy Technology Data Exchange (ETDEWEB)

    Sweeney, Lynn C. [Washington State Univ., Pullman, WA (United States)

    2013-04-01

    An exposure assessment was performed at the equipment and vehicle maintenance repair shops operating at the U. S. Department of Energy Hanford site, in Richland, Washington. The maintenance shops repair and maintain vehicles and equipment used in support of the Hanford cleanup mission. There are three general mechanic shops and one auto body repair shop. The mechanics work on heavy equipment used in construction, cranes, commercial motor vehicles, passenger-type vehicles in addition to air compressors, generators, and farm equipment. Services include part fabrication, installation of equipment, repair and maintenance work in the engine compartment, and tire and brake services. Work performed at the auto body shop includes painting and surface preparation which involves applying body filler and sanding. 8-hour time-weighted-average samples were collected for benzene and noise exposure and task-based samples were collected for lead dust work activities involving painted metal surfaces. Benzene samples were obtained using 3M™ 3520 sampling badges and were analyzed for additional volatile organic compounds. These compounds were selected based on material safety data sheet information for the aerosol products used by the mechanics for each day of sampling. The compounds included acetone, ethyl ether, toluene, xylene, VM&P naphtha, methyl ethyl ketone, and trichloroethylene. Laboratory data for benzene, VM&P naphtha, methyl ethyl ketone and trichloroethylene were all below the reporting detection limit. Airborne concentrations for acetone, ethyl ether, toluene and xylene were all less than 10% of their occupational exposure limit. The task-based samples obtained for lead dusts were submitted for a metal scan analysis to identify other metals that might be present. Laboratory results for lead dusts were all below the reporting detection limit and airborne concentration for the other metals observed in the samples were less than 10% of the occupational exposure limit

  8. Assimilation and transformation of benzene by higher plants

    Energy Technology Data Exchange (ETDEWEB)

    Durmishidze, S V; Ugrekhelidze, D Sh; Dzhikiya, A N

    1974-01-01

    Higher plants are capable of assimilating benzene, the molecules of which are subjected to deep chemical transformations; the products of its metabolism move along the plant. Taking part in total metabolism, carbon atoms of benzene molecules incorporate into composition of low-molecular compounds of the plant cell. The bulk of benzene carbon incorporates into composition of organic acids and a comparatively small part - into composition of amino acids. In the metabolism process benzene carbon localizes mainly in the chloroplasts. Phenol, muconic acid and CO/sub 2/ are isolated and identified from the products of benzene enzymatic oxidation. A range of benzene assimilation by higher plants is extremely wide. 9 references, 5 tables.

  9. The solubilities of benzene polycarboxylic acids in water

    International Nuclear Information System (INIS)

    Apelblat, Alexander; Manzurola, Emanuel; Abo Balal, Nazmia

    2006-01-01

    The solubilities in water of all benzene polycarboxylic acids are discussed, using data determined in this work (benzoic, terephthalic, trimellitic, trimesic, and pyromellitic acids) and available from the literature (benzoic, phthalic, isophthalic, terephthalic, hemimellitic, trimelitic, trimesic, mellophanic, prehnitic, pyromellitic, benzene-pentacarboxylic and mellitic acids). The apparent molar enthalpies of solution at the saturation point for these benzene polycarboxylic acids were determined from the temperature dependence of the solubilities

  10. The contribution of benzene to smoking-induced leukemia.

    OpenAIRE

    Korte, J E; Hertz-Picciotto, I; Schulz, M R; Ball, L M; Duell, E J

    2000-01-01

    Cigarette smoking is associated with an increased risk of leukemia; benzene, an established leukemogen, is present in cigarette smoke. By combining epidemiologic data on the health effects of smoking with risk assessment techniques for low-dose extrapolation, we assessed the proportion of smoking-induced total leukemia and acute myeloid leukemia (AML) attributable to the benzene in cigarette smoke. We fit both linear and quadratic models to data from two benzene-exposed occupational cohorts t...

  11. NMR study of conjugation effects. 15. /sup 13/C-/sup 13/C spin-spin coupling constants in phenylalkyl ether

    Energy Technology Data Exchange (ETDEWEB)

    Kalabin, G.A. (Siberian Branch of the Academy of Sciences of the USSR); Krivdin, L.B.; Trofimov, B.A.

    1982-07-20

    In order to elucidate the /sup 13/C-/sup 13/-C SSCC (spin-spin coupling constants) segment with the electronic excitations induced by the R group, a series of phenyl alkyl ethers, PhOAlk, where Alk = Me(I), Et(II), i-Pr(III), and t-Bu(IV), were studied. This series was chosen because in studying the /sup 13/C CS in monosubstituted benzenes it was observed that the intensity of the ..pi..-electron interaction of the unshared electron pairs of oxygen with the ..pi.. system of the benzene ring was practically the same in some compounds, but increased by 30% in others. This is related to the fact that the latter is characterized by an average noncoplanar conformation, with a dihedral angle between the benzene-ring plane and the C-O-C bond of approx. 45/sup 0/, whereas some compounds have an angle < 20/sup 0/. The reason for the difference is significant steric interaction of the alkyl hydrogens with the o-position of the ring. Thus, consideration of the /sup 13/C-/sup 13/C SSCC of a series of quite similar compounds, especially when compared to the whole set of such SSCC for other monosubstituted benzenes, shows that their relationship to the structure of the substituent R is extremely complex.

  12. Activity relationships for aromatic crown ethers

    International Nuclear Information System (INIS)

    Wilson, Mark James

    1998-01-01

    This thesis involves an investigation of aromatic crown ethers and a study of their binding constants for alkali metals. The study was motivated by the current needs of the semiconductor industry to improve the scavenging of mobile ions from fabricated circuits. A number of aromatic crown ethers have been sulphonated in an attempt to improve their water solubility and cation binding activity. These materials have been extensively studied and their binding activity determined. In collaboration with a molecular modelling study, the effect of ionisable sulphonate groups on the macrocycles' behaviour has been investigated. The broader issue of the effect of substituents in aromatic crown ethers has also been studied with the preparation of a wide range of substituted crown ethers. The cation binding activity of these materials has been found to bear a simple relationship to the electron withdrawing nature of the aromatic substituents. This relationship can be accurately monitored using electronic charge densities from molecular modelling and this rational has been applied to the study of proton ionisable and lariating crown ethers. The incorporation of crown ethers into polyamic acid and polyimide frameworks has also been investigated, where the resulting materials have been found to exhibit unusual cation binding and uptake properties. These results imply that the combination of the crown ethers' macrocycle and adjacent carboxylic acid residues, from the polyamic acids, are conducive to effective cationic binding. NMR measurements, in conjunction with molecular modelling, have been used to explore the geometry changes encountered as the crown ether goes from it's uncomplexed to its complexed state. The energy requirement for these geometry changes has subsequently been used to examine the cation selectivity of these materials. The electronic charge changes associated with the complexation have also been investigated and correlated with the theoretical results. (author)

  13. Exogenous ether lipids predominantly target mitochondria

    DEFF Research Database (Denmark)

    Kuerschner, Lars; Richter, Doris; Hannibal-Bach, Hans Kristian

    2012-01-01

    Ether lipids are ubiquitous constituents of cellular membranes with no discrete cell biological function assigned yet. Using fluorescent polyene-ether lipids we analyzed their intracellular distribution in living cells by microscopy. Mitochondria and the endoplasmic reticulum accumulated high......, accumulated to mitochondria and induced morphological changes and cellular apoptosis. These data indicate that edelfosine could exert its pro-apoptotic power by targeting and damaging mitochondria and thereby inducing cellular apoptosis. In general, this study implies an important role of mitochondria...

  14. Physiological and phylogenetic characterization of a stable benzene-degrading, chlorate-reducing microbial community

    NARCIS (Netherlands)

    Weelink, S.A.B.; Tan, N.C.G.; Broeke, H. ten; Doesburg, W. van; Langenhoff, A.A.M.; Gerritse, J.; Stams, A.J.M.

    2007-01-01

    A stable anoxic enrichment culture was obtained that degraded benzene with chlorate as an electron acceptor. The benzene degradation rate was 1.65 mM benzene per day, which is similar to reported aerobic benzene degradation rates but 20-1650 times higher than reported for anaerobic benzene

  15. Determination of average molecular weights on organic reactor coolants. II.-Freezing point depression method for diphenyl-ether solutions; Determinacion de masas moleculares medias en refrigerantes nucleares organicos. II.- Crioscopia de disoluciones en eter difenilico

    Energy Technology Data Exchange (ETDEWEB)

    Carreira, M

    1965-07-01

    In order to reduce limitations of solubility, the cryoscopic method developed for benzene solutions of polyphenyl mixtures has been extended to diphenyl-ether solutions by introducing some modifications imposed by the physico-chemical properties of this solvent. The Nernsto theory of Beckman's method has been revised, taking into account the heat-transfer characteristics of the system, and the results of that analysis have been used to fix upon the design parameters of a cryoscopic apparatus for measurements on diphenyl-ether solutions. (Author) 9 refs.

  16. Determination of average molecular weights on organic reactor coolants. II.-Freezing point depression method for diphenyl-ether solutions; Determinacion de masas moleculares medias en refrigerantes nucleares organicos. II.- Crioscopia de disoluciones en eter difenilico

    Energy Technology Data Exchange (ETDEWEB)

    Carreira, M.

    1965-07-01

    In order to reduce limitations of solubility, the cryoscopic method developed for benzene solutions of polyphenyl mixtures has been extended to diphenyl-ether solutions by introducing some modifications imposed by the physico-chemical properties of this solvent. The Nernsto theory of Beckman's method has been revised, taking into account the heat-transfer characteristics of the system, and the results of that analysis have been used to fix upon the design parameters of a cryoscopic apparatus for measurements on diphenyl-ether solutions. (Author) 9 refs.

  17. Accumulation of chlorinated benzenes in earthworms

    Science.gov (United States)

    Beyer, W.N.

    1996-01-01

    Chlorinated benzenes are widespread in the environment. Hexachlorobenzene, pentachlorobenzene and all isomers of dichlorobenzenes, trichlorobenzenes, and tetrachlorobenzenes, have been detected in fish, water, and sediments from the Great Lakes. This paper describes a long-term (26 week) experiment relating the concentrations of chlorinated benzenes in earthworms to 1) the length of exposure, and it describes three 8-week experiments relating concentrations of chlorinated benzenes in earthworms to 2) their concentration in soil 3) the soil organic matter content and, 4) the degree of chlorination. In the 26-week experiment, the concentration of 1,2,4 - trichlorobenzene in earthworms fluctuated only slightly about a mean of 0.63 ppm (Fig. 1). Although a statistically significant decrease can be demonstrated over the test (Pearson correlation coefficient, r = -0.62 p earthworms showed a cyclical trend that coincided with replacement of the media, and a slight but statistically significant tendency to increase from about 2 to 3 ppm over the 26 weeks (r = 0.55, p earthworms increased as the concentrations in the soil increased (Fig. 2), but leveled off at the highest soil concentrations. The most surprising result of this study was the relatively low concentrations in earthworms compared to those in soils. The average concentration of each of the six isomers of trichlorobenzene and tetrachlorobenzene in earthworms was only about 1 ppm (Table 2); the isomeric structure did not affect accumulation. The concentration of organic matter in soil had a prominent effect on hexachlorobenzene concentrations in earthworms (Fig. 3). Hexachlorobenzene concentrations decreased steadily from 9.3 ppm in earthworms kept in soil without any peat moss added to about 1 ppm in soil containing 16 or 32% organic matter.

  18. Benzene exposure in a Japanese petroleum refinery.

    Science.gov (United States)

    Kawai, T; Yamaoka, K; Uchida, Y; Ikeda, M

    1990-07-01

    Time-weighted average (TWA) intensity of exposure of workers to benzene vapor during a shift was monitored by diffusive sampling technique in a Japanese petroleum refinery. The subjects monitored (83 in total) included refinery operators, laboratory personnel and tanker-loading workers. The results showed that the time-weighted average exposures are well below 1 ppm in most cases. The highest exposure was recorded in 1 case involved in bulk loading of tanker ships, in which exposure of over 1 ppm might take place depending on operational conditions. The observation was generally in agreement with levels previously reported.

  19. Outline and operations of benzene plant

    Energy Technology Data Exchange (ETDEWEB)

    Omori, S; Hirooka, N; Nakamura, M; Goto, T

    1983-01-01

    An account is given of plant which can process 130,000 tonnes of by-product coke oven gas light oil (GLO) per year (via hydrodesulfurization, extraction and distillation) to produce benzene, toluene and xylene. The flowsheets and component equipment of the various production processes are explained, together with special features such as the production of hydrogen from coke oven gas by the PSA process and the processing of GLO by the ARCO process. Plant operation is outlined and the results of performance tests are noted.

  20. Benzene and cyclohexane separation using 1-butyl-3-methylimidazolium thiocyanate

    Science.gov (United States)

    Gonfa, Girma; Ismail, Marhaina; Bustam, Mohamad Azmi

    2017-09-01

    Cyclohexane is mainly produced by catalytic hydrogenation of benzene. Removal of unreacted benzene from the product stream is very important in this process. However, due to their close boiling points and azeotrope formation, it is very difficult to separate cyclohexane and benzene by conventional distillation. Currently, special separation processes such as processes extractive distillation is commercially used for this separation. However, this extractive distillation suffers from process complexity and higher energy consumption due to their low extractive selectivity of molecular entrainers used. The aim of the present work is to investigate the applicability of ionic liquids as entrainer in extractive distillation of benzene and cyclohexane mixture. In this study, we investigated 1-butyl-3-methylimidazolium thiocyanate ([BMIM][SCN]) ionic liquid for separation of benzene and cyclohexane by measuring the Vapor Liquid Equilibrium data of the two components in the presence of the ionic liquid. As green and potential environmentally friendly solvents, ionic liquids have attracted increasing attention as alternative conventional entrainers in extractive distillation. Isothermal Vapor Liquid Equilibrium for the benzene + cyclohexane + [BMIM][SCN] ternary system was obtained at 353.15 K using a Head Space Gas Chromatography. The addition of [BMIM][SCN] breaks the benzene-cyclohexane azeotrope and increased the relative volatility cyclohexane to benzene in the mixture. The effect of [BMIM][SCN] on the relative volatility cyclohexane to benzene was studied at various benzene and cyclohexane compositions and solvent to feed ratios. The performance of [BMIM][SCN] was compared with typical conventional solvents, dimethylformamide (DMF) and dimethylsulfoxide (DMSO). The results show that the relative volatility of cyclohexane to benzene in the presence of [BMIM][SCN] is higher compared that of DMSO and DMF.

  1. Benzene: a case study in parent chemical and metabolite interactions.

    Science.gov (United States)

    Medinsky, M A; Kenyon, E M; Schlosser, P M

    1995-12-28

    Benzene, an important industrial solvent, is also present in unleaded gasoline and cigarette smoke. The hematotoxic effects of benzene in humans are well documented and include aplastic anemia and pancytopenia, and acute myelogenous leukemia. A combination of metabolites (hydroquinone and phenol for example) is apparently necessary to duplicate the hematotoxic effect of benzene, perhaps due in part to the synergistic effect of phenol on myeloperoxidase-mediated oxidation of hydroquinone to the reactive metabolite benzoquinone. Since benzene and its hydroxylated metabolites (phenol, hydroquinone and catechol) are substrates for the same cytochrome P450 enzymes, competitive interactions among the metabolites are possible. In vivo data on metabolite formation by mice exposed to various benzene concentrations are consistent with competitive inhibition of phenol oxidation by benzene. In vitro studies of the metabolic oxidation of benzene, phenol and hydroquinone are consistent with the mechanism of competitive interaction among the metabolites. The dosimetry of benzene and its metabolites in the target tissue, bone marrow, depends on the balance of activation processes such as enzymatic oxidation and deactivation processes such as conjugation and excretion. Phenol, the primary benzene metabolite, can undergo both oxidation and conjugation. Thus, the potential exists for competition among various enzymes for phenol. However, zonal localization of Phase I and Phase II enzymes in various regions of the liver acinus regulates this competition. Biologically-based dosimetry models that incorporate the important determinants of benzene flux, including interactions with other chemicals, will enable prediction of target tissue doses of benzene and metabolites at low exposure concentrations relevant for humans.

  2. Novel crosslinked membranes based on sulfonated poly(ether ether ketone) for direct methanol fuel cells.

    Science.gov (United States)

    Zhu, Yuanqin; Zieren, Shelley; Manthiram, Arumugam

    2011-07-14

    Novel covalently crosslinked membranes based on sulfonated poly(ether ether ketone) and carboxylated polysulfone exhibit much lower methanol crossover and better performance in direct methanol fuel cells at 65 °C in 1 and 2 M methanol solutions compared to Nafion 115 membranes.

  3. Optical anisotropy, molecular orientations, and internal stresses in thin sulfonated poly(ether ether ketone) films

    NARCIS (Netherlands)

    Koziara, B.T.; Nijmeijer, K.; Benes, N.E.

    2015-01-01

    The thickness, the refractive index, and the optical anisotropy of thin sulfonated poly(ether ether ketone) films, prepared by spin-coating or solvent deposition, have been investigated with spectroscopic ellipsometry. For not too high polymer concentrations (≤5 wt%) and not too low spin speeds

  4. Optical anisotropy, molecular orientations, and internal stresses in thin sulfonated poly(ether ether ketone) films

    NARCIS (Netherlands)

    Koziara, Beata; Nijmeijer, Dorothea C.; Benes, Nieck Edwin

    2015-01-01

    The thickness, the refractive index, and the optical anisotropy of thin sulfonated poly(ether ether ketone) films, prepared by spin-coating or solvent deposition, have been investigated with spectroscopic ellipsometry. For not too high polymer concentrations (B5 wt%) and not too low spin speeds

  5. Thermal stability of sulfonated Poly(Ether Ether Ketone) films : on the role of Protodesulfonation

    NARCIS (Netherlands)

    Koziara, B.T.; Kappert, E.J.; Ogieglo, W.; Nijmeijer, Kitty; Hempenius, M.A.; Benes, N.E.

    Thin film and bulk, sulfonated poly(ether ether ketone) (SPEEK) have been subjected to a thermal treatment at 160–250 °C for up to 15 h. Exposing the films to 160 °C already causes partial desulfonation, and heating to temperatures exceeding 200 °C results in increased conjugation in the material,

  6. Deuteration of benzen derivatives and condensed aromatics

    International Nuclear Information System (INIS)

    Ichikawa, Masaru.

    1970-01-01

    A process for the deuteration of aromatic compounds (benzene derivatives having one or more cyano, halogeno, nitro or other electron attractive groups, and condensed ring aromatics) is provided. The process comprises reducing said aromatic compound with an alkali metal (preferably K, Rb or Cs) in a solvent (dimethoxyethane, tetrahydrofuran, etc.) to provide an electron-acceptor-donor complex, which is followed by introducing gaseous deuterium into the solution. The deuteration takes place selectively at the position of highest electron density in accordance with nature of the substituent, regardless of steric hindrance. The process is applicable to a wide variety of aromatics to give deuterated compounds in high yields. In one example, 5x10 -3 mole of anthracene (An) was reacted with 2g of metallic potassium in 80cc of dimethoxyethane in a N 2 atmosphere. Into the resulting solution of An=2K + was introduced D 2 gas (30 cmHg) at 25 0 C. After decomposition with air and washing with alcohol, the precipitate was recrystallized from benzene. Yield of recovered AN: more than 90%. Yield of deuteration: 100%. Position of deuteration: 9 and 10 (revealed by NMR and mass spectroscopy). (Kaichi, S.)

  7. Dissociative Photoionization of Diethyl Ether.

    Science.gov (United States)

    Voronova, Krisztina; Mozaffari Easter, Chrissa M; Covert, Kyle J; Bodi, Andras; Hemberger, Patrick; Sztáray, Bálint

    2015-10-29

    The dissociative photoionization of internal energy selected diethyl ether ions was investigated by imaging photoelectron photoion coincidence spectroscopy. In a large, 5 eV energy range Et2O(+) cations decay by two parallel and three sequential dissociative photoionization channels, which can be modeled well using statistical theory. The 0 K appearance energies of the CH3CHOCH2CH3(+) (H-loss, m/z = 73) and CH3CH2O═CH2(+) (methyl-loss, m/z = 59) fragment ions were determined to be 10.419 ± 0.015 and 10.484 ± 0.008 eV, respectively. The reemergence of the hydrogen-loss ion above 11 eV is attributed to transition-state (TS) switching, in which the second, outer TS is rate-determining at high internal energies. At 11.81 ± 0.05 eV, a secondary fragment of the CH3CHOCH2CH3(+) (m/z = 73) ion, protonated acetaldehyde, CH3CH═OH(+) (m/z = 45) appears. On the basis of the known thermochemical onset of this fragment, a reverse barrier of 325 meV was found. Two more sequential dissociation reactions were examined, namely, ethylene and formaldehyde losses from the methyl-loss daughter ion. The 0 K appearance energies of 11.85 ± 0.07 and 12.20 ± 0.08 eV, respectively, indicate no reverse barrier in these processes. The statistical model of the dissociative photoionization can also be used to predict the fractional ion abundances in threshold photoionization at large temperatures, which could be of use in, for example, combustion diagnostics.

  8. Benzene degradation coupled with chlorate reduction in soil column study

    NARCIS (Netherlands)

    Tan, N.C.G.; Doesburg, van W.C.J.; Langenhoff, A.A.M.; Stams, A.J.M.

    2006-01-01

    Perchlorate and chlorate are electron acceptors that during reduction result in the formation of molecular oxygen. The produced oxygen can be used for activation of anaerobic persistent pollutants, like benzene. In this study chlorate was tested as potential electron acceptor to stimulate benzene

  9. Evidence that humans metabolize benzene via two pathways.

    NARCIS (Netherlands)

    Rappaport, S.M.; Kim, S.; Lan, Q.; Vermeulen, R.C.H.; Waidyanatha, S.; Zhang, L.; Li, G.; Yin, S.; Hayes, R.B.; Rothman, N.; Smith, M.T.

    2009-01-01

    BACKGROUND: Recent evidence has shown that humans metabolize benzene more efficiently at environmental air concentrations than at concentrations > 1 ppm. This led us to speculate that an unidentified metabolic pathway was mainly responsible for benzene metabolism at ambient levels. OBJECTIVE: We

  10. The contribution of benzene to smoking-induced leukemia.

    Science.gov (United States)

    Korte, J E; Hertz-Picciotto, I; Schulz, M R; Ball, L M; Duell, E J

    2000-04-01

    Cigarette smoking is associated with an increased risk of leukemia; benzene, an established leukemogen, is present in cigarette smoke. By combining epidemiologic data on the health effects of smoking with risk assessment techniques for low-dose extrapolation, we assessed the proportion of smoking-induced total leukemia and acute myeloid leukemia (AML) attributable to the benzene in cigarette smoke. We fit both linear and quadratic models to data from two benzene-exposed occupational cohorts to estimate the leukemogenic potency of benzene. Using multiple-decrement life tables, we calculated lifetime risks of total leukemia and AML deaths for never, light, and heavy smokers. We repeated these calculations, removing the effect of benzene in cigarettes based on the estimated potencies. From these life tables we determined smoking-attributable risks and benzene-attributable risks. The ratio of the latter to the former constitutes the proportion of smoking-induced cases attributable to benzene. Based on linear potency models, the benzene in cigarette smoke contributed from 8 to 48% of smoking-induced total leukemia deaths [95% upper confidence limit (UCL), 20-66%], and from 12 to 58% of smoking-induced AML deaths (95% UCL, 19-121%). The inclusion of a quadratic term yielded results that were comparable; however, potency models with only quadratic terms resulted in much lower attributable fractions--all models substantially overestimate low-dose risk, linear extrapolations from empirical data over a dose range of 10- to 100-fold resulted in plausible predictions.

  11. Oxidative desulfurization of benzene fraction on transition metal oxides

    Science.gov (United States)

    Boikov, E. B.; Vishnetskaya, M. V.

    2013-02-01

    It is established that molecular oxygen is able to oxidize thiophene selectively in a mixture with benzene on V2O5 · MoO3. The introduction of thiophene inhibits the oxidation of benzene. It is shown that the conversion of thiophene during operation of the catalyst is reduced at first and then increases until it reaches its initial value.

  12. In situ synthesis of silver benzene-dithiolate hybrid films

    Energy Technology Data Exchange (ETDEWEB)

    Brenier, Roger, E-mail: roger.brenier@univ-lyon1.fr [Institut Lumière Matière, UMR 5306, Université Lyon 1-CNRS, Université de Lyon, Domaine Scientifique de La Doua, Batiment Kastler, 10 rue Ada Byron, 69622 Villeurbanne, Cedex (France); Piednoir, Agnès, E-mail: agnes.piednoir@univ-lyon1.fr [Institut Lumière Matière, UMR 5306, Université Lyon 1-CNRS, Université de Lyon, Domaine Scientifique de La Doua, Batiment Kastler, 10 rue Ada Byron, 69622 Villeurbanne, Cedex (France); Bertorelle, Franck, E-mail: franck.bertorelle@univ-lyon1.fr [Institut Lumière Matière, UMR 5306, Université Lyon 1-CNRS, Université de Lyon, Domaine Scientifique de La Doua, Batiment Kastler, 10 rue Ada Byron, 69622 Villeurbanne, Cedex (France); Penuelas, José, E-mail: jose.penuelas@ec-lyon.fr [Université de Lyon, Institut des Nanotechnologies de Lyon, Ecole Centrale de Lyon, CNRS, UMR 5270, 36 rue Guy de Collongues, F69134 Ecully (France); Grenet, Geneviève, E-mail: genevieve.grenet@ec-lyon.fr [Université de Lyon, Institut des Nanotechnologies de Lyon, Ecole Centrale de Lyon, CNRS, UMR 5270, 36 rue Guy de Collongues, F69134 Ecully (France)

    2016-02-01

    In this article, a method for in situ synthesis of silver benzene-dithiolate hybrid films is presented. Silver nanoparticles, generated on ZrO{sub 2} films, are transformed into silver benzene 1,4-dithiolate or, partially, into silver benzene 1,2-dithiolate after sample immersion in the corresponding thiol solutions. These transformations occur at room temperature owing to the catalytic action of ZrO{sub 2}. It is also shown that TiO{sub 2} in place of ZrO{sub 2} is very efficient, both for the catalytic generation of silver nanoparticles and for their further transformation in benzene 1,4-dithiolate compound. This latter semiconductor has an optical bandgap of about 3 eV and the film is made of touching nanoparticles in an amorphous state. Our work has potential applications in the electronic and photovoltaic fields. - Highlights: • A method for in situ synthesis of silver benzene-dithiolate hybrid semiconductor films is presented. • Silver nanoparticles are, first, generated on ZrO{sub 2} or on TiO{sub 2} coated silica substrates. • The samples are immersed in benzene dithiol solution for two days at room temperature. • During the immersion, the silver nanoparticles are transformed into silver benzene dithiolate. • The silver benzene dithiolate film is made of amorphous nanoparticles with a banbgap of 3 eV.

  13. Adduction of DNA with MTBE and TBA in mice studied by accelerator mass spectrometry.

    Science.gov (United States)

    Yuan, Y; Wang, H F; Sun, H F; Du, H F; Xu, L H; Liu, Y F; Ding, X F; Fu, D P; Liu, K X

    2007-12-01

    Methyl tert-butyl ether (MTBE) is a currently worldwide used octane enhancer substituting for lead alkyls and gasoline oxygenate. Our previous study using doubly (14)C-labeled MTBE [(CH(3))(3) (14)CO(14)CH(3)] has shown that MTBE binds DNA to form DNA adducts at low dose levels in mice. To elucidate the mechanism of the binding reaction, in this study, the DNA adducts with singly (14)C-labeled MTBE, which was synthesized from (14)C-methanol and tert-butyl alcohol (TBA), or (14)C-labeled TBA in mice have been measured by ultra sensitive accelerator mass spectrometry. The results show that the methyl group of MTBE and tert-butyl alcohol definitely form adducts with DNA in mouse liver, lung, and kidney. The methyl group of MTBE is the predominant binding part in liver, while the methyl group and the tert-butyl group give comparable contributions to the adduct formation in lung and kidney.

  14. Catalytic conversion of alcohols to hydrocarbons with low benzene content

    Energy Technology Data Exchange (ETDEWEB)

    Narula, Chaitanya K.; Davison, Brian H.; Keller, Martin

    2016-03-08

    A method for converting an alcohol to a hydrocarbon fraction having a lowered benzene content, the method comprising: converting said alcohol to a hydrocarbon fraction by contacting said alcohol, under conditions suitable for converting said alcohol to said hydrocarbon fraction, with a metal-loaded zeolite catalyst catalytically active for converting said alcohol to said hydrocarbon fraction, and contacting said hydrocarbon fraction with a benzene alkylation catalyst, under conditions suitable for alkylating benzene, to form alkylated benzene product in said hydrocarbon fraction. Also described is a catalyst composition useful in the method, comprising a mixture of (i) a metal-loaded zeolite catalyst catalytically active for converting said alcohol to said hydrocarbon, and (ii) a benzene alkylation catalyst, in which (i) and (ii) may be in a mixed or separated state. A reactor for housing the catalyst and conducting the reaction is also described.

  15. Catalytic conversion of alcohols to hydrocarbons with low benzene content

    Energy Technology Data Exchange (ETDEWEB)

    Narula, Chaitanya K.; Davison, Brian H.; Keller, Martin

    2016-09-06

    A method for converting an alcohol to a hydrocarbon fraction having a lowered benzene content, the method comprising: converting said alcohol to a hydrocarbon fraction by contacting said alcohol, under conditions suitable for converting said alcohol to said hydrocarbon fraction, with a metal-loaded zeolite catalyst catalytically active for converting said alcohol to said hydrocarbon fraction, and contacting said hydrocarbon fraction with a benzene alkylation catalyst, under conditions suitable for alkylating benzene, to form alkylated benzene product in said hydrocarbon fraction. Also described is a catalyst composition useful in the method, comprising a mixture of (i) a metal-loaded zeolite catalyst catalytically active for converting said alcohol to said hydrocarbon, and (ii) a benzene alkylation catalyst, in which (i) and (ii) may be in a mixed or separated state. A reactor for housing the catalyst and conducting the reaction is also described.

  16. Influence of benzene emission from motorcycle on Bangkok air quality

    Science.gov (United States)

    Leong, Shing Tet; Muttamara, S.; Laortanakul, Preecha

    This study investigated the influence of benzene concentration from motorcycle exhaust emissions on ambient air quality in Bangkok Metropolitan Region (BMR). Measurement of benzene concentration in exhaust emissions is performed on a standard test driving cycle through which each motorcycle to be tested is driven. The test result revealed that average benzene concentrations in exhaust emission for the test motorcycles ranged from 3.02 to 109.68 mg/m 3. The finding also indicated that two-stroke motorcycles emitted five times more benzene than that of four-stroke motorcycles. Four air monitoring sites were strategically established to determine the relationship between average benzene concentrations with different traffic configurations in each traffic zone of BMR during peak/non-peak hours, day/night times and weekday/weekend. The shape of the curve for benzene level usually shows two peaks corresponding to the morning and evening traffic rush or commuter rush hours. The finding shows that the mean concentrations for benzene in all monitoring stations in the ambient air for peak hours (07:00-09:00 and 16:00-18:00 h) ranged from 15.1 to 42.4 μg/m 3. For non-peak hour (11:30-15:00 h), benzene levels were found in the range 16.3-30.9 μg/m 3. It is observed that higher levels of benzene are found among roadside stations with slow moving traffic while lower levels are found among roadside stations with fast traffic movement. Additional factors such as temperature, wind speed, rainfall, etc. are also considered in this study to determine the relationship between traffic conditions and ambient benzene levels.

  17. Anaerobic degradation of benzene by marine sulfate-reducing bacteria

    Science.gov (United States)

    Musat, Florin; Wilkes, Heinz; Musat, Niculina; Kuypers, Marcel; Widdel, Friedrich

    2010-05-01

    Benzene, the archetypal aromatic hydrocarbon is a common constituent of crude oil and oil-refined products. As such, it can enter the biosphere through natural oil seeps or as a consequence of exploitation of fossil fuel reservoirs. Benzene is chemically very stable, due to the stabilizing aromatic electron system and to the lack of functional groups. Although the anaerobic degradation of benzene has been reported under denitrifying, sulfate-reducing and methanogenic conditions, the microorganisms involved and the initial biochemical steps of degradation remain insufficiently understood. Using marine sediment from a Mediterranean lagoon a sulfate-reducing enrichment culture with benzene as the sole organic substrate was obtained. Application of 16S rRNA gene-based methods showed that the enrichment was dominated (more than 85% of total cells) by a distinct phylotype affiliated with a clade of Deltaproteobacteria that include degraders of other aromatic hydrocarbons, such as naphthalene, ethylbenzene and m-xylene. Using benzoate as a soluble substrate in agar dilution series, several pure cultures closely related to Desulfotignum spp. and Desulfosarcina spp. were isolated. None of these strains was able to utilize benzene as a substrate and hybridizations with specific oligonucleotide probes showed that they accounted for as much as 6% of the total cells. Incubations with 13C-labeled benzene followed by Halogen in situ Hybridization - Secondary Ion Mass Spectroscopy (HISH-SIMS) analysis showed that cells of the dominant phylotype were highly enriched in 13C, while the accompanying bacteria had little or no 13C incorporation. These results demonstrate that the dominant phylotype was indeed the apparent benzene degrader. Dense-cell suspensions of the enrichment culture did not show metabolic activity toward added phenol or toluene, suggesting that benzene degradation did not proceed through anaerobic hydroxylation or methylation. Instead, benzoate was identified in

  18. Anaerobic benzene degradation under denitrifying conditions: Peptococcaceae was identified as dominant benzene degrader by Stable Isotope Probing (SIP)

    NARCIS (Netherlands)

    Zaan, van der B.M.; Talarico Saia, F.; Plugge, C.M.; Vos, de W.M.; Smidt, H.; Stams, A.J.M.; Langenhoff, A.A.M.; Gerritse, J.

    2012-01-01

    An anaerobic microbial community was enriched in a chemostat that was operated for more than 8 years with benzene and nitrate as electron acceptor. The coexistence of multiple species in the chemostat and the presence of a biofilm, led to the hypothesis that benzene-degrading species coexist in a

  19. Competitive Nitration of Benzene-Fluorobenzene and Benzene-Toluene Mixtures: Orientation and Reactivity Studies Using HPLC

    Science.gov (United States)

    Blankespoor, Ronald L.; Hogendoorn, Stephanie; Pearson, Andrea

    2007-01-01

    The reactivity and orientation effects of a substituent are analyzed by using HPLC to determine the competitive nitration of the benzene-toluene and benzene-fluorobenzene mixtures. The results have shown that HPLC is an excellent instrumental method to use in analyzing these mixtures.

  20. Injection characteristics of dimethyl ether

    Energy Technology Data Exchange (ETDEWEB)

    Glensvig, M.

    1996-09-01

    Dimethyl ether (DME) has proved to be a new ultra-clean alternative fuel for diesel engines. Engine tests have shown considerably lower NO{sub x} emissions, no particle emissions and lower noise compared to that obtained from normal diesel engine operation. DME also has demonstrated favorable response to Exhaust Gas Recirculation (EGR). The purpose of this investigation was to achieve a better understanding of the fundamental spray behavior of DME. Fundamental spray behaviour was characterized by fuel spray penetration and angle, atomization and droplet size and evaporation. The influence of fuel characteristics, nozzle geometry and ambient pressure on the DME and diesel spray behavior was investigated. Fuel was injected into an unheated injection chamber with a ambient pressure of 15 bar and 25 bar, respectively, giving a simplified simulation of the environment in an operating engine. Two nozzles were studied: a single hole nozzle and a pintle nozzle. A conventional fuel injection system was used for both nozzles. Injection parameters of RPM, throttle position, fuel line length and chamber environment were held constant for both nozzles. The sprays were visualized using schlieren and high speed photography. Results show that the general appearance of the DME spray is similar to that of diesel spray. The core of the DME spray seems less dense and the spray tip less sharp compared to diesel spray, indicating smaller droplets with a lower momentum in the core of the DME spray. Schlieren film shows that with both DME and diesel fuel, the spray tip only consists of liquid and that evaporation occurs after a brief time interval. Penetration of DME is about one third that of diesel using the pintle nozzle. Also, the spray angle is considerably larger for the DME spray compared to the diesel spray. A comparatively smaller difference in penetration is observed using the hole nozzle. Differences in penetration for the hole nozzle are within the limit of the penetration

  1. Radiation-induced transformations of cellulose ethers

    International Nuclear Information System (INIS)

    Nud'ga, L.A.; Petropavlovskii, G.S.; Plisko, E.A.; Isakova, O.V.; Ershov, B.G.

    1988-01-01

    The purpose of this investigation was to study the transformation which take place under the action of γ-radiation in a number of cellulose ethers containing both saturated (carboxymethyl, hydroxyethyl) and unsaturated (allyl, methacryloyl) groups. Irradiation was carried out on a 60 Co unit in air at 77 and 300 K; the dose rate was 37 and 50 kGy/h respectively. The EPR spectra of γ-irradiated hydroxyethyl- and allylhydroxyethylcelluloses are identical. Under the action of γ-radiation extensive changes took place in cellulose ethers which are exhibited in degradation or the formation of three-dimensional structures and are accompanied by a change in the functional composition. The efficiency in the formation of radicals and their localization are determined by the nature and number of substituents in the cellulose ethers

  2. Radical production in the radiolysis of benzene

    International Nuclear Information System (INIS)

    LaVerne, J.A.; Araos, M.S.

    1998-01-01

    Complete text of publication follows. Benzene is the prototypical aromatic compound and yet the radiation chemistry of the radicals formed in its radiolysis is not well understood. Temporal information on the yield of phenyl radical, the major radical produced in the radiolysis, is important for understanding the radiation chemistry of many other types of aromatic compounds including some polymers. The effects of track structure on the production of phenyl radicals have been examined using iodine-scavenging techniques. The variation of the yields of iodobenzene and the other major molecular products such as biphenyl as a function of iodine concentration gives a good indication of the competition kinetics occurring in particle tracks. Experimental results of the scavenger experiments will be shown and their implications in the radiolysis of condensed hydrocarbons will be discussed

  3. Benzene exposure and risk of non-Hodgkin lymphoma.

    Science.gov (United States)

    Smith, Martyn T; Jones, Rachael M; Smith, Allan H

    2007-03-01

    Exposure to benzene, an important industrial chemical and component of gasoline, is a widely recognized cause of leukemia, but its association with non-Hodgkin lymphoma (NHL) is less clear. To clarify this issue, we undertook a systematic review of all case-control and cohort studies that identified probable occupational exposures to benzene and NHL morbidity or mortality. We identified 43 case-control studies of NHL outcomes that recognized persons with probable occupational exposure to benzene. Forty of these 43 (93%) studies show some elevation of NHL risk, with 23 of 43 (53%) studies finding statistically significant associations between NHL risk and probable benzene exposure. We also identified 26 studies of petroleum refinery workers reporting morbidity or mortality for lymphomas and all neoplasms and found that in 23 (88%), the rate of lymphoma morbidity or mortality was higher than that for all neoplasms. A substantial healthy-worker effect was evident in many of the studies and a comprehensive reevaluation of these studies with appropriate adjustments should be undertaken. Numerous studies have also reported associations between benzene exposure and the induction of lymphomas in mice. Further, because benzene is similar to alkylating drugs and radiation in producing leukemia, it is plausible that it might also produce lymphoma as they do and by similar mechanisms. Potential mechanisms include immunotoxicity and the induction of double-strand breaks with subsequent chromosome damage resulting in translocations and deletions. We conclude that, overall, the evidence supports an association between occupational benzene exposure and NHL.

  4. Benzene exposure is associated with cardiovascular disease risk.

    Directory of Open Access Journals (Sweden)

    Wesley Abplanalp

    Full Text Available Benzene is a ubiquitous, volatile pollutant present at high concentrations in toxins (e.g. tobacco smoke known to increase cardiovascular disease (CVD risk. Despite its prevalence, the cardiovascular effects of benzene have rarely been studied. Hence, we examined whether exposure to benzene is associated with increased CVD risk. The effects of benzene exposure in mice were assessed by direct inhalation, while the effects of benzene exposure in humans was assessed in 210 individuals with mild to high CVD risk by measuring urinary levels of the benzene metabolite trans,trans-muconic acid (t,t-MA. Generalized linear models were used to assess the association between benzene exposure and CVD risk. Mice inhaling volatile benzene had significantly reduced levels of circulating angiogenic cells (Flk-1+/Sca-1+ as well as an increased levels of plasma low-density lipoprotein (LDL compared with control mice breathing filtered air. In the human cohort, urinary levels of t,t-MA were inversely associated several populations of circulating angiogenic cells (CD31+/34+/45+, CD31+/34+/45+/AC133-, CD34+/45+/AC133+. Although t,t-MA was not associated with plasma markers of inflammation or thrombosis, t,t-MA levels were higher in smokers and in individuals with dyslipidemia. In smokers, t,t-MA levels were positively associated with urinary metabolites of nicotine (cotinine and acrolein (3-hydroxymercapturic acid. Levels of t,t-MA were also associated with CVD risk as assessed using the Framingham Risk Score and this association was independent of smoking. Thus, benzene exposure is associated with increased CVD risk and deficits in circulating angiogenic cells in both smokers and non-smokers.

  5. On new physical reality (on ψ-ether)

    International Nuclear Information System (INIS)

    Isaev, P.S.

    2002-01-01

    It is shown that there exists a new physical reality - the ψ-ether. All the achievements of quantum mechanics and quantum field theory are due to the fact that both the theories include the influence of ψ-ether on the physical processes occurring in the Universe. Physics of the XX century was first of all the physics of ψ-ether

  6. Children's exposure to polybrominated diphenyl ethers.

    NARCIS (Netherlands)

    Zuurbier, M.; Leijs, M.; Schoeters, G.; Tusscher, G. Ten; Koppe, J.G.

    2006-01-01

    Background: Polybrominated biphenyl ethers (PBDEs), a class of brominated flame retardants, are frequently used in consumer products. PBDEs levels in environmental and human samples have increased in recent decades. Children are exposed to PBDEs through diet, mainly through fish, meat and milk.

  7. Polybrominated diphenyl ethers and novel flame retardants

    DEFF Research Database (Denmark)

    Frederiksen, Marie; Vorkamp, Katrin; Nielsen, Jesper Bo

    ,4,6-tribromophenyl ether (TBP-DBPE) and dechlorane plus (DDC-CO) have been detected in the same dust samples previously analysed for PBDEs and are currently being analysed in the corresponding human milk samples. [1] Stapleon H.M., Eagle S., Sjödin A., Webster T.F. (2012). Serum PBDEs in a North Carolina Toddler...

  8. [Visualisation methods for etheric formative forces].

    Science.gov (United States)

    Burkhard, B; Kittel, R

    2009-09-01

    Rudolf Steiner, the founder of anthroposophy, suggested the development of visualisation methods for "etheric formative forces". The essential methods, their "spiritual scientific" basis and indications are described and their claims critically tested. The methods are not validated, the key criteria for diagnostic tests (reproducibility, sensitivity, specifity) are not given.

  9. Degradation of organic pollutants by methane grown microbial consortia.

    Science.gov (United States)

    Hesselsoe, Martin; Boysen, Susanne; Iversen, Niels; Jørgensen, Lars; Murrell, J Colin; McDonald, Ian; Radajewski, Stefan; Thestrup, Helle; Roslev, Peter

    2005-10-01

    Microbial consortia were enriched from various environmental samples with methane as the sole carbon and energy source. Selected consortia that showed a capacity for co-oxidation of naphthalene were screened for their ability to degrade methyl-tert-butyl-ether (MTBE), phthalic acid esters (PAE), benzene, xylene and toluene (BTX). MTBE was not removed within 24 h by any of the consortia examined. One consortium enriched from activated sludge ("AAE-A2"), degraded PAE, including (butyl-benzyl)phthalate (BBP), and di-(butyl)phthalate (DBP). PAE have not previously been described as substrates for methanotrophic consortia. The apparent Km and Vmax for DBP degradation by AAE-A2 at 20 degrees C was 3.1 +/- 1.2 mg l(-1) and 8.7 +/- 1.1 mg DBP (g protein x h)(-1), respectively. AAE-A2 also showed fast degradation of BTX (230 +/- 30 nmol benzene (mg protein x h)(-1) at 20 degrees C). Additionally, AAE-A2 degraded benzene continuously for 2 weeks. In contrast, a pure culture of the methanotroph Methylosinus trichosporium OB3b ceased benzene degradation after only 2 days. Experiments with methane mono-oxygenase inhibitors or competitive substrates suggested that BTX degradation was carried out by methane-oxidizing bacteria in the consortium, whereas the degradation of PAE was carried out by non-methanotrophic bacteria co-existing with methanotrophs. The composition of the consortium (AAE-A2) based on polar lipid fatty acid (PLFA) profiles showed dominance of type II methanotrophs (83-92% of biomass). Phylogeny based on a 16S-rRNA gene clone library revealed that the dominating methanotrophs belonged to Methylosinus/Methylocystis spp. and that members of at least 4 different non-methanotrophic genera were present (Pseudomonas, Flavobacterium, Janthinobacterium and Rubivivax).

  10. The influence of different light quality and benzene on gene expression and benzene degradation of Chlorophytum comosum.

    Science.gov (United States)

    Setsungnern, Arnon; Treesubsuntorn, Chairat; Thiravetyan, Paitip

    2017-11-01

    Benzene, a carcinogenic compound, has been reported as a major indoor air pollutant. Chlorophytum comosum (C. comosum) was reported to be the highest efficient benzene removal plant among other screened plants. Our previous studies found that plants under light conditions could remove gaseous benzene higher than under dark conditions. Therefore, C. comosum exposure to airborne benzene was studied under different light quality at the same light intensity. C. comosum could remove 500 ppm gaseous benzene with the highest efficiency of 68.77% under Blue:Red = 1:1 LED treatments and the lowest one appeared 57.41% under white fluorescent treatment within 8 days. After benzene was uptaken by C. comosum, benzene was oxidized to be phenol in the plant cells by cytochrome P450 monooxygenase system. Then, phenol was catalyzed to be catechol that was confirmed by the up-regulation of phenol 2-monooxygenase (PMO) gene expression. After that, catechol was changed to cic, cis-muconic acid. Interestingly, cis,cis-muconic acid production was found in the plant tissues higher than phenol and catechol. The result confirmed that NADPH-cytochrome P450 reductase (CPR), cytochrome b5 (cyt b5), phenol 2-monooxygenase (PMO) and cytochrome P450 90B1 (CYP90B1) in plant cells were involved in benzene degradation or detoxification. In addition, phenol, catechol, and cis,cis-muconic acid production were found under the Blue-Red LED light conditions higher than under white fluorescent light conditions due to under LED light conditions gave higher NADPH contents. Hence, C. comosum under the Blue-Red LED light conditions had a high potential to remove benzene in a contaminated site. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  11. Microwave sintering of poly-ether-ether-ketone (PEEK) based coatings deposited on metallic substrate

    International Nuclear Information System (INIS)

    Zhang, G.; Leparoux, S.; Liao, H.; Coddet, C.

    2006-01-01

    In this paper, the feasibility of microwave (MW) sintering PEEK (poly-ether-ether-ketone) based coatings was investigated. Three coatings were studied: pure PEEK, micron-SiC and nano-SiC particles filled (wt.10%) PEEK coatings. The results indicate that, for the two composite coatings, the SiC particles distributed in the polymer matrix, as a good MW susceptor, could be heated preferentially by MW radiation. Consequently, the polymer matrix was heated by these particles

  12. Selective crystallization of cations with crown ethers

    International Nuclear Information System (INIS)

    Heffels, Dennis Egidius

    2014-01-01

    The aim of this work was to study the selectivity and preferences of the incorporation of differently sized cations in the cavities of various crown ethers and the characterization of the resulting compounds. The coordination preferences of crown ethers with different cavities have long been known, and the impact of other effects on the structure formation have increasingly become the focus of attention. In this work a comparative overview of the coordination preferences depending on various factors was undertaken. The focus was mainly on the variation of the cavity of the crown ether in the presence of differently sized cations. In addition, the effects of the solvent and differently coordinating anions have been investigated. Within the framework of this work, basic coordination preferences could be detected with rare earth nitrates, which are affected particularly by the choice of the solvent. The formation of different types of structures could be controlled by varying the conditions such that the incorporation of the cation in the cavity of the crown ether was influenced and the formation of a particular type of structure can be influenced partly by the choice of solvent. In this case no direct preferences for the incorporation into the cavity of the crown ether in relation to the cation size were observed for rare earth cations. However, the coordination of the crown ether leads in each case - for lanthanides - to rather high coordination numbers. A total of five new rare earth complexes and two structural variants could be observed with crown ethers. In the study of the selectivity of the incorporation into the cavity, known structures were also reproduced and further structures were characterized but the crystal structures not entirely solved. With the use of monovalent cations such as potassium, lithium or silver a total of nine new compounds could be synthesized, while no clear preferences for the incorporation of certain cations were detected. The

  13. Ion-Selective Ionic Polymer Metal Composite (IPMC) actuator based on crown ether containing sulfonated Poly(Arylene Ether Ketone)

    NARCIS (Netherlands)

    Tas, S.; Zoetebier, B.; Sukas, O.S.; Bayraktar, M.; Hempenius, M.; Vancso, G.J.; Nijmeijer, K.

    2017-01-01

    This study introduces the concept of ion selective actuation in polymer metal composite actuators, employing crown ether bearing aromatic polyether materials. For this purpose, sulfonated poly(arylene ether ketone) (SPAEK) and crown ether containing SPAEK with molar masses suitable for membrane

  14. Electronic structure of benzene adsorbed on Ni and Cu surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Weinelt, M.; Nilsson, A.; Wassdahl, N. [Uppsala Univ. (Sweden)] [and others

    1997-04-01

    Benzene has for a long time served as a prototype adsorption system of large molecules. It adsorbs with the molecular plane parallel to the surface. The bonding of benzene to a transition metal is typically viewed to involve the {pi} system. Benzene adsorbs weakly on Cu and strongly on Ni. It is interesting to study how the adsorption strength is reflected in the electronic structure of the adsorbate-substrate complex. The authors have used X-ray Emission (XE) and X-ray Absorption (XA) spectroscopies to selectively study the electronic states localized on the adsorbed benzene molecule. Using XES the occupied states can be studies and with XAS the unoccupied states. The authors have used beamline 8.0 and the Swedish endstation equipped with a grazing incidence x-ray spectrometer and a partial yield absorption detector. The resolution in the XES and XAS were 0.5 eV and 0.05 eV, respectively.

  15. Variability of benzene exposure among filling station attendants

    International Nuclear Information System (INIS)

    Carere, A.; Iacovella, N.; Turrio Baldassarri, L.; Fuselli, S.; Iavarone, I.; Lagorio, S.; Proietto, A.R.

    1996-12-01

    A monitoring survey of filling station attendants aimed at identifying sources of variability of exposure to benzene and other aromatics was carried out. Concurrent samples of the worker's breathing zone air, atmospheric air in the service station proximity, and gasoline were collected, along with information about daily workloads and other exposure-related factors. Benzene personal exposure was characterised by a small between-worker variability and a predominant within-worker variance component. Such elevated day-to-day variability yields to imprecise estimates of mean personal exposure. Almost 70% of the overall personal exposure variance was explained by a model including daily benzene from dispensed fuel, presence of a shelter over the refueling area, amount of fuel supplied to the station if a delivery occurred, and background atmospheric benzene concentration

  16. Process for making propenyl ethers and photopolymerizable compositions containing them

    Science.gov (United States)

    Crivello, James V.

    1996-01-01

    Propenyl ether monomers of formula V A(OCH.dbd.CHCH.sub.3).sub.n wherein n is an integer from one to six and A is selected from cyclic ethers, polyether and alkanes are disclosed. The monomers are readily polymerized in the presence of cationic photoinitiators, when exposed to actinic radiation, to form poly(propenyl ethers) that are useful for coatings, sealants, varnishes and adhesives. Compositions for preparing polymeric coatings comprising the compounds of formula V together with particular cationic photoinitiators are also disclosed, as are processes for making the monomers from allyl halides and readily available alcohols. The process involves rearranging the resulting allyl ethers to propenyl ethers.

  17. Radiation-induced cationic curing of vinyl ethers

    International Nuclear Information System (INIS)

    Lapin, S.C.

    1992-01-01

    Recently there has been an increasing interest in nonacrylate radiation-curable coatings. Vinyl ethers are particularly reactive under cationic polymerization reaction conditions. The high efficiency of the photoacid initiators combined with the high reactivity of vinyl ether monomers makes this a potentially very useful system. This chapter discusses the preparation of vinyl ethers, introduces vinyl ether-functional monomers and oligomers, describes radiation-induced cationic polymerization of vinyl ethers, and discusses various coating systems. Throughout the chapter, an emphasis is placed on radiation-curable coating applications. 64 refs., 5 figs., 11 tabs

  18. Determination of benzene in exhaust gas from biofuels. Final report; Bestimmung von Benzol im Abgas von Biokraftstoffen. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Dutz, M.; Buenger, J.; Gnuschke, H.; Halboth, H.; Gruedl, P.; Krahl, J.

    2001-10-01

    With the advance of environmental legislation and practices oriented towards sustainability renewable energy resources are becoming increasingly important. Use of replenishable raw materials helps preserve fossil resources. In the fuel sector the most widely used replenishable materials are rape methyl ester (RME) and ethyl tertiary butyl ether (ETBE). The purpose of the present project on the ''Determination of benzene in exhaust gas from biofuels'' was to generate orienting data on the potential health relevance of mixtures of fossil and renewable fuel intended for use in spark ignition and diesel engines. This included a determination of benzene emissions and the mutagenicity of particles. Beyond the applied-for scope of research measurements were also performed on the test engine's toluene, ethyl benzene and xylene emissions as well as on the smoke spot number and nitrogen oxide (NO{sub x}) and hydrocarbon (HC) emissions of the diesel engine. [German] Regenerative Energien gewinnen durch die Umweltgesetzgebungen und das Streben nach einer nachhaltigen Entwicklung zunehmend an Bedeutung. Durch die Verwendung nachwachsender Rohstoffe koennen die fossilen Ressourcen geschont werden. Im Kraftstoffsektor sind hier hauptsaechlich Rapsoelmethylester (RME) und optional Ethyltertiaerbutylether (ETBE) zu nennen. Um fuer Diesel- und Ottomotoren insbesondere mit Blick auf Kraftstoffgemische aus fossilen und regenerativen Komponenten orientierende Daten ueber eine potenzielle Gesundheitsrelevanz zu generieren, wurde das Projekt 'Bestimmung von Benzol im Abgas von Biokraftstoffen' durchgefuehrt. Neben der Benzolemission wurde die Mutagenitaet der Partikeln ermittelt. Ueber den beantragten Untersuchungsrahmen hinaus wurden die Tuluol-, Ethylbenzol-, und Xylolemissionen der eingesetzten Motoren, sowie die Russzahl (RZ) und die Stickoxid- (NO{sub x}) und Kohlenwasserstoffemissionen (HC) des Dieselmotors bestimmt. (orig.)

  19. Positronium quenching in liquid and solid octanol and benzene

    DEFF Research Database (Denmark)

    Shantarovich, V.P.; Mogensen, O.E.; Goldanskii, V.I.

    1970-01-01

    The lifetimes of orthopositronium in several solutions in liquid and solid octanol and benzene have been measured. The Ps-quenching constant was found to be two to thirty times higher in the solid than in the liquid phase.......The lifetimes of orthopositronium in several solutions in liquid and solid octanol and benzene have been measured. The Ps-quenching constant was found to be two to thirty times higher in the solid than in the liquid phase....

  20. Phytoremediation of a petroleum-hydrocarbon contaminated shallow aquifer in Elizabeth City, North Carolina, USA

    Science.gov (United States)

    Nichols, Elizabeth Guthrie; Cook, Rachel L.; Landmeyer, James E.; Atkinson, Brad; Malone, Donald R.; Shaw, George; Woods, Leilani

    2014-01-01

    A former bulk fuel terminal in North Carolina is a groundwater phytoremediation demonstration site where 3,250 hybrid poplars, willows, and pine trees were planted from 2006 to 2008 over approximately 579,000 L of residual gasoline, diesel, and jet fuel. Since 2011, the groundwater altitude is lower in the area with trees than outside the planted area. Soil-gas analyses showed a 95 percent mass loss for total petroleum hydrocarbons (TPH) and a 99 percent mass loss for benzene, toluene, ethylbenzene, and xylenes (BTEX). BTEX and methyl tert-butyl ether concentrations have decreased in groundwater. Interpolations of free-phase, fuel product gauging data show reduced thicknesses across the site and pooling of fuel product where poplar biomass is greatest. Isolated clusters of tree mortalities have persisted in areas with high TPH and BTEX mass. Toxicity assays showed impaired water use for willows and poplars exposed to the site's fuel product, but Populus survival was higher than the willows or pines on-site, even in a noncontaminated control area. All four Populus clones survived well at the site.

  1. Air sparging of organic compounds in groundwater

    International Nuclear Information System (INIS)

    Hicks, P.M.

    1994-01-01

    Soils and aquifers containing organic compounds have been traditionally treated by excavation and disposal of the soil and/or pumping and treating the groundwater. These remedial options are often not practical or cost effective solutions. A more favorable alternative for removal of the adsorbed/dissolved organic compounds would be an in situ technology. Air sparging will remove volatile organic compounds from both the adsorbed and dissolved phases in the saturated zone. This technology effectively creates a crude air stripper below the aquifer where the soil acts as the ''packing''. The air stream that contacts dissolved/adsorbed phase organics in the aquifer induces volatilization. A case history illustrates the effectiveness of air sparging as a remedial technology for addressing organic compounds in soil and groundwater. The site is an operating heavy equipment manufacturing facility in central Florida. The soil and groundwater below a large building at the facility was found to contain primarily diesel type petroleum hydrocarbons during removal of underground storage tanks. The organic compounds identified in the groundwater were Benzene, Xylenes, Ethylbenzene and Toluenes (BTEX), Methyl tert-Butyl Ether (MTBE) and naphthalenes in concentrations related to diesel fuel

  2. Investigation of MTBE and aromatic compound concentrations at a gas service station.

    Science.gov (United States)

    Lin, Chi-Wen; Chiang, Song-Bor; Lu, San-Ju

    2005-06-01

    Methyl tert-butyl ether (MTBE) has been used as a fuel additive at levels of 2-11% in Taiwan for the past decade. The purpose of this additive is to enhance the octane, replace the use of lead-based anti-knock gasoline additives and reduce aromatic hydrocarbons. However, it is possible that oxygenated fuel has a potential health impact. To determine the air quality impact of MTBE, measurements were made of ambient MTBE and other gasoline constituents at a service station. Additionally, environmental conditions (wind speed, wind direction, and temperature, etc.) that could affect concentrations of emission constituents were measured. Gas samples were analyzed for target MTBE and volatile organic compounds, e.g., benzene and toluene. Ambient samples were collected using Tenax adsorbent tubes for mass spectrometric analysis at a service station located in Changhua County, Taiwan. The resulting measured ambient air concentrations were compared with Taiwan's regulatory standards for hazardous air pollutants. Subsequently, the factors controlling the formation of high-VOC levels at the service station and in the residential neighborhoods were identified. Additionally, the results can provide the Environmental Protection Agency (EPA) of Taiwan with useful information and prompt them to mandate this gas service station to install a refueling vapor recovery system.

  3. Occupational exposure to gasoline and the risk of non-Hodgkin lymphoma: a review and meta-analysis of the literature.

    Science.gov (United States)

    Kane, Eleanor V; Newton, Rob

    2010-10-01

    Gasoline comprises over 500 chemicals, including the known or suspected carcinogens benzene, 1,3-butadiene, ethylbenzene and methyl tert-butyl ether (MTBE). To assess whether work in the production, distribution and use of gasoline is associated with non-Hodgkin lymphoma (NHL), we reviewed the published literature on this topic. English-language peer-reviewed articles were identified by keyword searches of bibliographic databases. Twenty-two cohorts and thirteen case-control studies examined the risk of NHL among persons employed in the downstream petroleum industry. No positive associations were found with the exception of one study. The pooled risk estimate from a random-effects meta-analysis was 1.02 (95% confidence interval (CI) 0.94-1.12). Although there were no estimates available, exposure is likely to have varied by occupation, location and time period; there was no evidence however that risk estimates varied by any of these factors. NHL is a heterogeneous disease, yet no data were reported for NHL subtypes. In summary, there is no suggestion across an extensive literature that exposure to gasoline at the levels workers' experience in an occupational setting increases the risk of NHL. Copyright © 2010 Elsevier Ltd. All rights reserved.

  4. Potential occurrence of MTBE and BTEX in groundwater resources of Amman-Zarqa basin, Jordan

    International Nuclear Information System (INIS)

    Al Kuisi, Mustafa; Saffarini, Ghazi; Yaseen, Najal; Alawi, Mahmoud

    2012-01-01

    This study investigates potential occurrence, distribution, and sources of the newly added gasoline oxygenate, methyl-tert-butyl ether (MTBE) and the petroleum derivatives benzene, toluene, ethylbenzene, and xylenes called collectively, BTEX, in Jordan's heavily populated Amman-Zarqa Basin (AZB). It presents the first data on the levels of MTBE and BTEX in the aquifers of this basin. One hundred and seventy-nine (179) groundwater wells were sampled near petrol service stations, oil refinery storage tanks, car wrecks, bus stations, and chemical industries at different locations in the basin. Headspace GC and purge and trap GC-MS were utilized to determine the target substances in the samples. Concentrations of BTEX varied between no-detection (minimum) for all of them to 6.6 μg/L (maximum) for ethylbenzene. MTBE was found in few samples but none has exceeded the regulated levels; its concentrations ranged between no-detection to 4.1 μg/L. However, though the contamination levels are very low they should be considered alarming. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  5. Monitoring of the Gasoline Oxygenate MTBE and BTEX Compounds in Groundwater in Catalonia (Northeast Spain

    Directory of Open Access Journals (Sweden)

    J. Fraile

    2002-01-01

    Full Text Available Headspace (HS gas chromatography with flame ionisation detection (HS-GC-FID and purge and trap (P gas chromatography-mass spectrometry (P were used for the determination of methyl-tert-butyl ether (MTBE and benzene, toluene, and xylenes (BTEX in groundwater. In this work, we present the first data on the levels of MTBE and BTEX in different groundwater wells in the area of Catalonia (northeast Spain. This monitoring campaign corresponded to 28 groundwater wells that were located near petrol service stations, oil refinery storage tanks, and/or chemical industry at different locations of Catalonia during the period of 1998/1999. The levels of MTBE detected varied between 4—300 μg/l, but two sites had MTBE levels up to 3 and 13 mg/l. In many cases, the BTEX levels were below 1 μg/l, whereas 7 sites had levels varying from 19 μg/l up to 3 mg/l. Most of them were related to leakage from underground tanks in petrol service stations, while the remaining three corresponded respectively to chemical industrial pollution of undetermined origin and to a leak from high-ground petrol tanks in petrochemical refinery factories. The aquifers involved were constituted by detritus coarse materials, sands, and conglomerates. Piezometric levels were roughly comprised between 3 and 40 m, and permeability (K and transmissivity (T values were estimated from field measurements.

  6. Real-time ambient air monitoring adjacent to the Houston ship channel for volatile organic compounds associated with the refinery operations using the trace atmospheric gas analyzer (TAGA)

    International Nuclear Information System (INIS)

    Mickunas, D.B.

    2009-01-01

    An Urban Air Toxic Monitoring Program was developed by the United States Environmental Protection Agency (US EPA) to help evaluate the potential toxic air pollution in urban areas. The Trace Atmospheric Gas Analyzer (TAGA) was used to monitor the ambient air for target compounds associated with industrial, motor vehicle, and natural emissions sources in areas adjacent to the Houston Ship Channel in Texas. In this study, the TAGA used triple quadrupole technology to perform qualitative and quantitative analyses for benzene, toluene, xylenes, styrene, 1,3-butadiene, methyl tert-butyl ether, and 1,2,3-trichloropropane. The concentrations for the various ion pairs of the target compounds were updated approximately every 2 seconds. The information was incorporated into the geographic information system (GIS) along with the global positioning system (GPS) information for the TAGA location, aerial views of the monitoring area, and meteorological data for the associated region. The information is used to isolate the emission sources and help reduce air pollution. The GPS output helps determine a path-averaged concentration along various routes. Combined with meteorological data, this information can be used in risk assessment to calculate downwind impacts associated with the target compounds under other meteorological conditions and to determine health impacts. It was concluded that the TAGA can provide rapid, accurate and reliable analytical information for monitoring ambient air. 2 refs., 1 tab., 9 figs

  7. Real-time ambient air monitoring adjacent to the Houston ship channel for volatile organic compounds associated with the refinery operations using the trace atmospheric gas analyzer (TAGA)

    Energy Technology Data Exchange (ETDEWEB)

    Mickunas, D.B. [United States Environmental Protection Agency, Research Triangle Park, NC (United States). Environmental Response Team; Wood, J.; Weeks, W. [Lockheed Martin Response Engineering and Analytical Contract, Edison, NJ (Canada)

    2009-07-01

    An Urban Air Toxic Monitoring Program was developed by the United States Environmental Protection Agency (US EPA) to help evaluate the potential toxic air pollution in urban areas. The Trace Atmospheric Gas Analyzer (TAGA) was used to monitor the ambient air for target compounds associated with industrial, motor vehicle, and natural emissions sources in areas adjacent to the Houston Ship Channel in Texas. In this study, the TAGA used triple quadrupole technology to perform qualitative and quantitative analyses for benzene, toluene, xylenes, styrene, 1,3-butadiene, methyl tert-butyl ether, and 1,2,3-trichloropropane. The concentrations for the various ion pairs of the target compounds were updated approximately every 2 seconds. The information was incorporated into the geographic information system (GIS) along with the global positioning system (GPS) information for the TAGA location, aerial views of the monitoring area, and meteorological data for the associated region. The information is used to isolate the emission sources and help reduce air pollution. The GPS output helps determine a path-averaged concentration along various routes. Combined with meteorological data, this information can be used in risk assessment to calculate downwind impacts associated with the target compounds under other meteorological conditions and to determine health impacts. It was concluded that the TAGA can provide rapid, accurate and reliable analytical information for monitoring ambient air. 2 refs., 1 tab., 9 figs.

  8. 'POSM II' finds markets playing dead

    International Nuclear Information System (INIS)

    Morris, G.D.L.

    1993-01-01

    Technology has been in service several years coproducing styrene with propylene oxide (PO), or PO with methyl tert-butyl ether (MTBE). But with the recent addition of Arco Chemical's second world-scale PO/styrene plant (POSM II) at Channelview, TX, and the pending completion of Texaco Chemical's mammoth MTBE/PO plant at Port Neches, TX, the three markets are becoming firmly intertwined. At present, all three markets are over-supplied in North America and balanced to soft worldwide. But with the wave of new capacity, the three products are likely to become increasingly unstable, as strong demand in one serves to wash the others in unwanted coproduct. As market watchers see it now, styrene is the weakest sister, with poor prospects until toward the end of the decade. MTBE capacity additions are in a lull but will pick up again as the next Clean Air Act gasoline reformulation deadline nears in 1995. PO demand is still growing worldwide sufficiently to prompt several companies - including Arco - to consider new plants. Traditionally buffeted by the vagaries of the ethylene and benzene markets, styrene has already been hurt once by a knock-on effect from PO. 'Today it isn't so bad because the PO market is down,' says one styrene producer. 'But in the mid-80's styrene was so bad, and PO was very good, and Arco ran for PO. It really burdened styrene

  9. Thermophilic biofiltration of benzene and toluene.

    Science.gov (United States)

    Cho, Kyung-Suk; Yoo, Sun-Kyung; Ryu, Hee Wook

    2007-12-01

    In the current studies, we characterized the degradation of a hot mixture of benzene and toluene (BT) gases by a thermophilic biofilter using polyurethane as packing material and high-temperature compost as a microbial source. We also examined the effect of supplementing the biofilter with yeast extract (YE). We found that YE substantially enhanced microbial activity in the thermophilic biofilter. The degrading activity of the biofilter supplied with YE was stable during long-term operation (approximately 100 d) without accumulating excess biomass. The maximum elimination capacity (1,650 g x m(-3) h(-1)) in the biofilter supplemented with YE was 3.5 times higher than that in the biofilter without YE (470 g g x m(-3) h(-1)). At similar retention times, the capacity to eliminate BT for the YE-supplemented biofilter was higher than for previously reported mesophilic biofilters. Thus, thermophilic biofiltration can be used to degrade hydrophobic compounds such as a BT mixture. Finally, 16S rDNA polymerase chain reaction-DGGE (PCR-DGGE) fingerprinting revealed that the thermophilic bacteria in the biofilter included Rubrobacter sp. and Mycobacterium sp.

  10. Determination of Glycol Ethers in Ambient Air by Adsorption Sampling and Thermal Desorption with GC/MS Analysis: Performance Evaluation and Field Application

    Directory of Open Access Journals (Sweden)

    Young-Kyo Seo

    2012-01-01

    Full Text Available Some of glycol ethers, such as 2-methoxyethanol (2-ME and 2-ethoxyethanol (2-EE are known to be toxic and classified as hazardous air pollutants in USA, Japan and Germany. In Korea, however, there has been no study conducted so far for these compounds in ambient air. In addition, no clear methodologies for the measurement of glycol ethers have been yet established. We carried out this study to evaluate a sampling and analytical method for the determination of glycol ethers, in ambient air samples collected in specific industrial areas of South Korea. To measure glycol ethers, adsorption sampling and thermal desorption with GC/MS analysis were used in this study. The analytical method showed good repeatability, linearity and sensitivity. The lower detection limits were estimated to be approximately 0.3∼0.5 ppb. Based on storage tests, it was suggested that samples should be analyzed within two weeks. It was also demonstrated that this method can be used for the simultaneous measurement of glycol ethers and other aromatic VOCs such as benzene, toluene, and xylenes. Field sampling campaign was carried out at 2 sites, located in a large industrial area, from October 2006 to June 2007, and a total of 480 samples were collected seasonally. Among them, 2-ME was not detected from any samples, while 2-EE and 2-Ethyloxyethylacetate (2-EEA were found in 7 and 70 samples, respectively. The measured concentrations of 2-EE and 2-EEA for samples were ranged from 0.7-2.5 ppb and from 0.5-10.5 ppb, respectively. To our knowledge, this is the first measurement report for glycol ethers in the ambient atmosphere not only in Korea but also the rest of the world.

  11. Cultivating microbial dark matter in benzene-degrading methanogenic consortia.

    Science.gov (United States)

    Luo, Fei; Devine, Cheryl E; Edwards, Elizabeth A

    2016-09-01

    The microbes responsible for anaerobic benzene biodegradation remain poorly characterized. In this study, we identified and quantified microbial populations in a series of 16 distinct methanogenic, benzene-degrading enrichment cultures using a combination of traditional 16S rRNA clone libraries (four cultures), pyrotag 16S rRNA amplicon sequencing (11 cultures), metagenome sequencing (1 culture) and quantitative polymerase chain reaction (qPCR; 12 cultures). An operational taxonomic unit (OTU) from the Deltaproteobacteria designated ORM2 that is only 84% to 86% similar to Syntrophus or Desulfobacterium spp. was consistently identified in all enrichment cultures, and typically comprised more than half of the bacterial sequences. In addition to ORM2, a sequence belonging to Parcubacteria (candidate division OD1) identified from the metagenome data was the only other OTU common to all the cultures surveyed. Culture transfers (1% and 0.1%) were made in the presence and absence of benzene, and the abundance of ORM2, OD1 and other OTUs was tracked over 415 days using qPCR. ORM2 sequence abundance increased only when benzene was present, while the abundance of OD1 and other OTUs increased even in the absence of benzene. Deltaproteobacterium ORM2 is unequivocally the benzene-metabolizing population. This study also hints at laboratory cultivation conditions for a member of the widely distributed yet uncultivated Parcubacteria (OD1). © 2015 Society for Applied Microbiology and John Wiley & Sons Ltd.

  12. Environmental and biological monitoring of benzene during self-service automobile refueling.

    OpenAIRE

    Egeghy, P P; Tornero-Velez, R; Rappaport, S M

    2000-01-01

    Although automobile refueling represents the major source of benzene exposure among the nonsmoking public, few data are available regarding such exposures and the associated uptake of benzene. We repeatedly measured benzene exposure and uptake (via benzene in exhaled breath) among 39 self-service customers using self-administered monitoring, a technique rarely used to obtain measurements from the general public (130 sets of measurements were obtained). Benzene exposures averaged 2.9 mg/m(3) (...

  13. 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.

  14. Synthesis of densely grafted copolymers with tert-butyl methacrylate/2-(dimethylamino ethyl) methacrylate side chains as precursors for brush polyelectrolytes and polyampholytes

    Czech Academy of Sciences Publication Activity Database

    Gromadzki, Daniel; Štěpánek, Petr; Makuška, R.

    2013-01-01

    Roč. 137, č. 3 (2013), s. 709-715 ISSN 0254-0584 R&D Projects: GA ČR GA202/09/2078 Institutional research plan: CEZ:AV0Z40500505 Keywords : polymers * fourier transform infrared spectroscopy (FTIR) * nuclear magnetic resonance (NMR) Subject RIV: BO - Biophysics Impact factor: 2.129, year: 2013

  15. Experimental and Theoretical Investigation of the Function of 4- tert-Butyl Pyridine for Interface Energy Level Adjustment in Efficient Solid-State Dye-Sensitized Solar Cells.

    Science.gov (United States)

    Yang, Lei; Lindblad, Rebecka; Gabrielsson, Erik; Boschloo, Gerrit; Rensmo, Håkan; Sun, Licheng; Hagfeldt, Anders; Edvinsson, Tomas; Johansson, Erik M J

    2018-04-11

    4- tert-Butylpyridine ( t-BP) is commonly used in solid state dye-sensitized solar cells (ssDSSCs) to increase the photovoltaic performance. In this report, the mechanism how t-BP functions as a favorable additive is investigated comprehensively. ssDSSCs were prepared with different concentrations of t-BP, and a clear increase in efficiency was observed up to a maximum concentration and for higher concentrations the efficiency thereafter decreases. The energy level alignment in the complete devices was measured using hard X-ray photoelectron spectroscopy (HAXPES). The results show that the energy levels of titanium dioxide are shifted further away from the energy levels of spiro-OMeTAD as the t-BP concentration is increased. This explains the higher photovoltage obtained in the devices with higher t-BP concentration. In addition, the electron lifetime was measured for the devices and the electron lifetime was increased when adding t-BP, which can be explained by the recombination blocking effect at the surface of TiO 2 . The results from the HAXPES measurements agree with those obtained from density functional theory calculations and give an understanding of the mechanism for the improvement, which is an important step for the future development of solar cells including t-BP.

  16. Vibrational spectra and ab initio analysis of tert-butyl, trimethylsilyl, and trimethylgermyl derivatives of 3,3-dimethylcyclopropene . VI: Application of observed trends to stannyl derivatives

    Science.gov (United States)

    Panchenko, Yu. N.; De Maré, G. R.; Abramenkov, A. V.; Baird, M. S.; Tverezovsky, V. V.; Nizovtsev, A. V.; Bolesov, I. G.

    2004-09-01

    The effects of substitution of X=C by Si or Ge in X(CH 3) 3 moieties attached to the formal double bond of 3,3-dimethylcyclopropene are examined. Regularities in observed trends of vibrational frequencies implicating the moieties containing the X atom, as the X atomic mass is increased, are extrapolated to X=Sn. The results of this extrapolation made it possible to assign the known experimental vibrational frequencies of 3,3-dimethyl-1-(trimethylstannyl)cyclopropene and 3,3-dimethyl-1,2-bis(trimethylstannyl)cyclopropene.

  17. Vibrational spectra and ab initio analysis of tert-butyl, trimethylsilyl, and trimethylgermyl derivatives of 3,3-dimethylcyclopropene III. 3,3-Dimethyl-1-(trimethylsilyl)cyclopropene

    Science.gov (United States)

    De Maré, G. R.; Panchenko, Yu. N.; Abramenkov, A. V.; Baird, M. S.; Tverezovsky, V. V.; Nizovtsev, A. V.; Bolesov, I. G.

    2003-07-01

    The experimental Raman and IR vibrational spectra of 3,3-dimethyl-1-(trimethylsilyl)cyclopropene in the liquid phase were recorded. Total geometry optimisation was carried out at the HF/6-31G* level and the HF/6-31G*//HF/6-31G* force field was computed. This force field was corrected by scale factors determined previously (using Pulay's method) for correction of the HF/6-31G*//HF/6-31G* force fields of 3,3-dimethylbutene-1, 1-methyl-, 1,2-dimethyl-, and 3,3-dimethylcyclopropene. The theoretical vibrational frequencies calculated from the scaled quantum mechanical force field and the theoretical intensities obtained from the quantum mechanical calculation were used to construct predicted spectra and to perform the vibrational analysis of the experimental spectra.

  18. Effect of free-radical spin trap N-tert-butyl-alpha-phenylnitrone on seizures induced in immature rats by homocysteic acid

    Czech Academy of Sciences Publication Activity Database

    Folbergrová, Jaroslava; Druga, Rastislav; Otáhal, Jakub; Haugvicová, Renata; Mareš, Pavel; Kubová, Hana

    2005-01-01

    Roč. 46, č. S6 (2005), s. 375-375 ISSN 0013-9580. [International Epilepsy Congress /26./. 28.08.2005-01.09.2005, Paris] R&D Projects: GA ČR(CZ) GA309/02/1238; GA ČR(CZ) GA309/05/2015 Keywords : free radical scavenger * epilepsy * immature rats * homocysteic acid Subject RIV: ED - Physiology

  19. MALDI-TOF MS analysis of the self-termination products in the anionic methyl methacrylate/tert-butyl acrylate block copolymerization

    Czech Academy of Sciences Publication Activity Database

    Vlček, Petr; Čadová, Eva; Horský, Jiří; Janata, Miroslav

    2015-01-01

    Roč. 72, č. 9 (2015), s. 2227-2239 ISSN 0170-0839 Institutional support: RVO:61389013 Keywords : anionic polymerization * acrylates * block copolymer Subject RIV: CD - Macromolecular Chemistry Impact factor: 1.371, year: 2015

  20. [2,6-Bis(di-tert-butyl-phosphinometh-yl)-phen-yl-κP,C,P'](nitrato-κO)nickel(II).

    Science.gov (United States)

    Boro, Brian J; Dickie, Diane A; Duesler, Eileen N; Goldberg, Karen I; Kemp, Richard A

    2008-10-15

    The Ni(II) atom in the title compound, [Ni(C(24)H(43)P(2))(NO(3))], adopts a distorted square-planar geometry with the P atoms in a trans arrangement. The compound contains a twofold rotational axis with the nitrate group offset from this axis, except for an O atom of the nitrate group, generating two positions of 50% occupancy for the other atoms of the nitrate group.

  1. 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.

  2. (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.

  3. Study of 2-methyl -2-oxo-3,5-di-tert.-butyl-Δ4-1,3,2-oxazaphospholine interaction with lanthanide shifting reagents

    International Nuclear Information System (INIS)

    Turov, A.V.; Povolotskij, M.I.; Balitskij, Yu.V.; Kornilov, M.Yu.; Boldeskul, I.E.

    1983-01-01

    2-methyl-2-oxo-3.5-di-tret.-butyl-Δ 4 -1, 3, 2-oxazaphospholine in CDCl 3 solution reacts with lanthanide shifting reagents-tris (dipivaloylmethanates) of europium (3) and praseodymium (3)-with the formation of adducts of constant composition. At that, in ( + H, 13 C) NMR spectra considerable pseudocontact induced shifts of substratum signals take place. Geometry of the adducts formed is calculated

  4. Administration of PBN (N-tert-butyl-alfa-phenylnitrone) during status epilepticus reduces neuronal injury, improves cognitive functions but enhances epileptogenesis in immature rats

    Czech Academy of Sciences Publication Activity Database

    Kubová, Hana; Folbergrová, Jaroslava; Otáhal, Jakub; Mareš, Pavel

    2007-01-01

    Roč. 59, Suppl. 1 (2007), s. 10-10 ISSN 1734-1140. [Day of neuropsychopharmacology /16./. 06.09.2007-08.09.2007, Wroclaw] Institutional research plan: CEZ:AV0Z50110509 Keywords : PBN * status epilepticus * immature rats Subject RIV: ED - Physiology

  5. Crystal structure of (1R,4R-tert-butyl 3-oxo-2-oxa-5-azabicyclo[2.2.2]octane-5-carboxylate

    Directory of Open Access Journals (Sweden)

    Suvratha Krishnamurthy

    2015-07-01

    Full Text Available In the title compound, C11H17NO4, commonly known as N-tert-butoxycarbonyl-5-hydroxy-d-pipecolic acid lactone, the absolute configuration is (1R,4R due to the enantiomeric purity of the starting material which remains unchanged during the course of the reaction. In the crystal there no intermolecular hydrogen bonds.

  6. Effect of free radical spin trap N-tert-butyl-alpha-phenylnitrone (PBN) on seizures induced in immature rats by homocysteic acid

    Czech Academy of Sciences Publication Activity Database

    Folbergrová, Jaroslava; Druga, Rastislav; Otáhal, Jakub; Haugvicová, Renata; Mareš, Pavel; Kubová, Hana

    2006-01-01

    Roč. 201, č. 1 (2006), s. 105-119 ISSN 0014-4886 R&D Projects: GA ČR(CZ) GA309/05/2015; GA ČR(CZ) GA309/02/1238 Institutional research plan: CEZ:AV0Z50110509; CEZ:AV0Z50200510 Keywords : DL-homocysteic acid induced seizures * neuronal damage * protection Subject RIV: ED - Physiology Impact factor: 4.156, year: 2006

  7. Electron exchange by hexakis(tert-butyl-isocyanide)- and hexakis(cyclohexyl isocyanide)manganese(I,II). Solvent effect on the rate constant and the volume of activation

    International Nuclear Information System (INIS)

    Stebler, M.; Nielson, R.M.; Siems, W.F.; Hunt, J.P.; Dodgen, H.W.; Wherland, H.W.

    1988-01-01

    The rate of electron self-exchange of Mn(CNC(CH 3 ) 3 ) 6 +/2+ and Mn(CNC 6 H 11 ) 6 +/2+ as the BF 4 - salts has been measured by 55 Mn NMR line broadening as a function of pressure, temperature, and concentration in acetonitrile, bromobenzene, benzonitrile, acetone, diethyl ketone, methanol, ethanol, methylene chloride, and trimethyl phosphate, and various binary mixtures of methylene chloride, bromobenzene, and acetonitrile. The values of ΔV double dagger obtained are negative and cover a range of ca. 12 cm 3 /mol, which is limited by ion pairing in the solvents of lower dielectric constant. The variation of the ambient pressure rate constant with solvent is qualitatively different for Mn(CNC(CH 3 ) 3 ) 6 +/2+ reaction than was observed for the Mn(CNC 6 H 11 ) 6 +/2+ reaction. This is taken as further evidence for a significant influence of rather subtle differences in solvation on the molecular level that are not approximated by dielectric continuum models. 30 references, 3 tables

  8. Difunctionalization of alkenes with iodine and tert-butyl hydroperoxide (TBHP) at room temperature for the synthesis of 1-(tert-butylperoxy)-2-iodoethanes.

    Science.gov (United States)

    Wang, Hao; Chen, Cui; Liu, Weibing; Zhu, Zhibo

    2017-01-01

    We developed a direct vicinal difunctionalization of alkenes with iodine and TBHP at room temperature. This iodination and peroxidation in a one-pot synthesis produces 1-( tert -butylperoxy)-2-iodoethanes, which are inaccessible through conventional synthetic methods. This method generates multiple radical intermediates in situ and has excellent regioselectivity, a broad substrate scope and mild conditions. The iodine and peroxide groups of 1-( tert -butylperoxy)-2-iodoethanes have several potential applications and allow further chemical modifications, enabling the preparation of synthetically valuable molecules.

  9. Di-tert-butyl­bis(N-isopropyl-N-methyl­dithio­carbamato-κ2 S,S′)tin(IV)

    Science.gov (United States)

    Muthalib, Amirah Faizah; Baba, Ibrahim; Samsudin, Mohd Wahid; Ng, Seik Weng

    2010-01-01

    The dithio­carbamate anions in the title compound, [Sn(C4H9)2(C5H10NS2)2], chelate to the SnIV atom, which is six-coordinated in a skew-trapezoidal-bipyramidal geometry. The mol­ecule lies across a twofold rotation axis. The crystal studied was a non-merohedral twin, the ratio of the twin components being 0.82 (1):0.18 (1). PMID:21580471

  10. Exposition by inhalation to the benzene, toluene, ethyl-benzene and xylenes (BTEX) in the air. Sources, measures and concentrations

    International Nuclear Information System (INIS)

    Del Gratta, F.; Durif, M.; Fagault, Y.; Zdanevitch, I.

    2004-12-01

    This document presents the main techniques today available to characterize the benzene, toluene, ethyl-benzene and xylene (BTEX) concentrations in the air for different contexts: urban and rural areas or around industrial installations but also indoor and occupational area. It provides information to guide laboratories and research departments. A synthesis gives also the main emissions sources of these compounds as reference concentrations measured in different environments. (A.L.B.)

  11. Hardness and wear properties of boron-implanted poly(ether-ether-ketone) and poly-ether-imide

    International Nuclear Information System (INIS)

    Lee Youngchul; Lee, E.H.; Mansur, L.K.

    1992-01-01

    The effects of boron beam irradiation on the hardness, friction, and wear of polymer surfaces were investigated. Typical high-performance thermoplastics, poly(ether-ether-ketone) (PEEK) and a poly-ether-imide (Ultem) were studied after 200 keV boron ion beam treatment at ambient temperature to doses of 2.3x10 14 , 6.8x10 14 , and 2.2x10 15 ions cm -2 . The hardnesses of pristine and boron-implanted materials were characterized by a conventional Knoop method and a load-depth sensing nanoindentation technique. Both measurements showed a significant increase in hardness with increasing dose. The increase in hardness was also found to depend on the penetration depth of the diamond indenter. Wear and friction properties were characterized by a reciprocating sliding friction tester with an SAE 52100 high-carbon, chrome steel ball at 0.5 and 1 N normal loads. Wear and frictional properties varied in a complex fashion with polymer type and dose, but not much with normal load. A substantial reduction in friction coefficient was observed for PEEK at the highest dose but no reduction was observed for Ultem. The wear damage was substantially reduced at the highest dose for both Ultem and PEEK. For the system studied, the highest dose, 2.2x10 15 ions cm -2 , appears to be optimum in improving wear resistance for both PEEK and Ultem. (orig.)

  12. On the Use of Potential Denaturing Agents for Ethanol in Direct Ethanol Fuel Cells

    OpenAIRE

    Domnik Bayer; Florina Jung; Birgit Kintzel; Martin Joos; Carsten Cremers; Dierk Martin; Jörg Bernard; Jens Tübke

    2011-01-01

    Acidic or alkaline direct ethanol fuel cells (DEFCs) can be a sustainable alternative for power generation if they are fuelled with bio-ethanol. However, in order to keep the fuel cheap, ethanol has to be exempted from tax on spirits by denaturing. In this investigation the potential denaturing agents fusel oil, tert-butyl ethyl ether, and Bitrex were tested with regard to their compatibility with fuel cells. Experiments were carried out both in sulphuric acid and potassium hydroxide solution...

  13. Demonstration of the AGI Universal Samplers (F.K.A. the GORE Modules) for Passive Sampling of Groundwater

    Science.gov (United States)

    2014-03-27

    and lower Hen- ry’s Law constants are biased low (Anderson 2013). In this instance, me- thyl tert-butyl ether (MTBE) is lost entirely and 1,2...coolers full of ice or blue ice to transport samples to the laboratory. One limitation associated with using the GORE Module is that, like all no- purge...was taken from Dunbar et al. (2001). A regional geologic and geomorphic model was developed for the Aberdeen Prov- ing Ground (APG). Regional

  14. Demonstration of the AGI Universal Samplers (F.K.A. the GORE (registered trademark) Modules) for Passive Sampling of Groundwater

    Science.gov (United States)

    2014-03-01

    and lower Hen- ry’s Law constants are biased low (Anderson 2013). In this instance, me- thyl tert-butyl ether (MTBE) is lost entirely and 1,2...coolers full of ice or blue ice to transport samples to the laboratory. One limitation associated with using the GORE Module is that, like all no- purge...was taken from Dunbar et al. (2001). A regional geologic and geomorphic model was developed for the Aberdeen Prov- ing Ground (APG). Regional

  15. Improved Understanding of In Situ Chemical Oxidation. Technical Objective I: Contaminant Oxidation Kinetics Contaminant Oxidation Kinetics

    Science.gov (United States)

    2009-05-01

    methyl tert butyl ether NAPL non-aqueous phase liquid NOD natural oxidant demand •OH hydroxide radical Ox oxidant O3 ozone PCE...and persulfate; and Technical Objective 2, assess how soil properties (e.g., soil mineralogy , natural carbon content) affect oxidant mobility and...to develop a general description of kobs vs. T because there are many reactions that can contribute to the concentration of the reactive intermediate

  16. Biodegradation of MTBE in reactors

    OpenAIRE

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

    2007-01-01

    The fuel oxygenate methyl tert-butyl ether (MTBE) was first introduced in the 1970’s to improve gasoline combustion efficiency and reduce emission of harmful gases. However, it has caused groundwater contamination in Denmark and in many locations worldwide through accidental releases from leaking underground gasoline storage tanks and pipelines. Both laboratory experiments and mathematical computer models were used to acquire knowledge on the scientific and engineering aspects related to the ...

  17. Radiolytic decomposition of 4-bromodiphenyl ether

    International Nuclear Information System (INIS)

    Tang Liang; Xu Gang; Wu Wenjing; Shi Wenyan; Liu Ning; Bai Yulei; Wu Minghong

    2010-01-01

    Polybrominated diphenyl ethers (PBDEs) spread widely in the environment are mainly removed by photochemical and anaerobic microbial degradation. In this paper, the decomposition of 4-bromodiphenyl ether (BDE -3), the PBDEs homologues, is investigated by electron beam irradiation of its ethanol/water solution (reduction system) and acetonitrile/water solution (oxidation system). The radiolytic products were determined by GC coupled with electron capture detector, and the reaction rate constant of e sol - in the reduction system was measured at 2.7 x 10 10 L · mol -1 · s -1 by pulsed radiolysis. The results show that the BDE-3 concentration affects strongly the decomposition ratio in the alkali solution, and the reduction system has a higher BDE-3 decomposition rate than the oxidation system. This indicates that the BDE-3 was reduced by effectively capturing e sol - in radiolytic process. (authors)

  18. Model for Photodegradation of Polybrominated Diphenyl Ethers

    Czech Academy of Sciences Publication Activity Database

    Veselý, M.; Vajglová, Zuzana; Kotas, Petr; Křišťál, Jiří; Ponec, Robert; Jiřičný, Vladimír

    2015-01-01

    Roč. 22, č. 7 (2015), s. 4949-4963 ISSN 0944-1344 R&D Projects: GA ČR GA104/09/0880; GA ČR(CZ) GAP105/12/0664 Institutional support: RVO:67985858 ; RVO:67179843 Keywords : polybrominated diphenyl ethers * photodegradation model * quantum chemical calculation Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 2.760, year: 2015

  19. Promoting environmentally sound management of polybrominated diphenyl ethers in Asia.

    Science.gov (United States)

    Li, Jinhui; Zhao, Nana; Liu, Xue; Wu, Xiaoyang

    2014-06-01

    Polybrominated diphenyl ethers with persistent organic pollutant properties are required to be controlled by the Stockholm Convention. Recently, polybrominated diphenyl ether contamination has become widespread in Asia, mainly because of the disposal and recycling processes of polybrominated diphenyl ether-containing wastes. The management status, production, usage, import/export, treatment, and disposal, as well as implementation deficiencies for the environmentally sound management of polybrominated diphenyl ethers and polybrominated diphenyl ether-containing materials in ten Asian countries were investigated and assessed in this study. This information could help the participating countries implement the Stockholm Convention and could promote the regional environmentally sound management of polybrominated diphenyl ether-containing articles and products. The results obtained were as follows. (1) Most of the countries studied lacked environmental policies and regulations, or even standards of polybrominated diphenyl ether pollution management and emission control actions. Accurate data on the consumption and importation of polybrominated diphenyl ether-containing materials, however, were not available for all the participating countries. In addition, there were no special treatment or disposal systems for polybrominated diphenyl ether-containing materials, or emission-cutting measures for the treatment of waste in these countries, owing to the lack of sufficient funding or technologies. (2) The improper dismantling of e-waste is a major source of polybrominated diphenyl ether emissions in these countries. (3) Proper e-waste management could result in a breakthrough in the environmentally sound management of this major polybrominated diphenyl ether-containing material flow, and could significantly reduce polybrominated diphenyl ether emissions. Finally, based on the study results, this article puts forward some recommendations for improving the environmentally

  20. Nikola Tesla, the Ether and his Telautomaton

    Science.gov (United States)

    Milar, Kendall

    2014-03-01

    In the nineteenth century physicists' understanding of the ether changed dramatically. New developments in thermodynamics, energy physics, and electricity and magnetism dictated new properties of the ether. These have traditionally been examined from the perspective of the scientists re-conceptualizing the ether. However Nikola Tesla, a prolific inventor and writer, presents a different picture of nineteenth century physics. Alongside the displays that showcased his inventions he presented alternative interpretations of physical, physiological and even psychical research. This is particularly evident in his telautomaton, a radio remote controlled boat. This invention and Tesla's descriptions of it showcase some of his novel interpretations of physical theories. He offered a perspective on nineteenth century physics that focused on practical application instead of experiment. Sometimes the understanding of physical theories that Tesla reached was counterproductive to his own inventive work; other times he offered new insights. Tesla's utilitarian interpretation of physical theories suggests a more scientifically curious and invested inventor than previously described and a connection between the scientific and inventive communities.