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1

DIMETHYL ETHER (DME)-FUELED SHUTTLE BUS DEMONSTRATION PROJECT  

SciTech Connect

The objectives of this research and demonstration program are to convert a campus shuttle bus to operation on dimethyl ether, a potential ultra-clean alternative diesel fuel. To accomplish this objective, this project includes laboratory evaluation of a fuel conversion strategy, as well as, field demonstration of the DME-fueled shuttle bus. Since DME is a fuel with no lubricity (i.e., it does not possess the lubricating quality of diesel fuel), conventional fuel delivery and fuel injection systems are not compatible with dimethyl ether. Therefore, to operate a diesel engine on DME one must develop a fuel-tolerant injection system, or find a way to provide the necessary lubricity to the DME. In this project, they have chosen the latter strategy in order to achieve the objective with minimal need to modify the engine. Their strategy is to blend DME with diesel fuel, to obtain the necessary lubricity to protect the fuel injection system and to achieve low emissions. The bulk of the efforts over the past year were focused on the conversion of the campus shuttle bus. This process, started in August 2001, took until April 2002 to complete. The process culminated in an event to celebrate the launching of the shuttle bus on DME-diesel operation on April 19, 2002. The design of the system on the shuttle bus was patterned after the system developed in the engine laboratory, but also was subjected to a rigorous failure modes effects analysis (FMEA, referred to by Air Products as a ''HAZOP'' analysis) with help from Dr. James Hansel of Air Products. The result of this FMEA was the addition of layers of redundancy and over-pressure protection to the system on the shuttle bus. The system became operational in February 2002. Preliminary emissions tests and basic operation of the shuttle bus took place at the Pennsylvania Transportation Institute's test track facility near the University Park airport. After modification and optimization of the system on the bus, operation on the campus shuttle route began in early June 2002. However, the work and challenges continued as it has been difficult to maintain operability of the shuttle bus due to fuel and component difficulties. In late June 2002, the pump head itself developed operational problems (loss of smooth function) leading to excessive stress on the magnetic coupling and excessive current draw to operate. A new pump head was installed on the system to alleviate this problem and the shuttle bus operated successfully on DME blends from 10-25 vol% on the shuttle bus loop until September 30, 2002. During the period of operation on the campus loop, the bus was pulled from service, operated at the PTI test track and real-time emissions measurements were obtained using an on-board emissions analyzer from Clean Air Technologies International, Inc. Particulate emissions reductions of 60% and 80% were observed at DME blend ratios of 12 vol.% and 25 vol.%, respectively, as the bus was operated over the Orange County driving cycle. Increases in NOx, CO and HC emissions were observed, however. In summary, the conversion of the shuttle bus was successfully accomplished, particulate emissions reductions were observed, but there were operational challenges in the field. Nonetheless, they were able to demonstrate reliable operation of the shuttle bus on DME-diesel blends.

Elana M. Chapman; Shirish Bhide; Jennifer Stefanik; Howard Glunt; Andre L. Boehman; Allen Homan; David Klinikowski

2003-04-01

2

Development of a Nuclear Hydrogen Production System by Dimethyl Ether (DME) Steam Reforming and Related Technology  

NASA Astrophysics Data System (ADS)

Targeting a hydrogen production system using heat produced by a nuclear reactor at about 300°C, we are developing a dimethyl ether (DME) steam reformer and hydrogen purification systems as well as catalysts for DME reforming. The use of heat from a nuclear reactor suppresses the CO2 concentration change in the atmosphere. In our developments, a catalyst, consisting of mixed oxides, produced hydrogen at a rate of about 1.9 Nm3/h per catalyst volume (m3) at about 300°C. Subsequently, the DME steam reformer achieved a hydrogen production rate of approximately, at least, 1.4 Nm3/h at about 300°C, by absorbing heat from the supplied steam. The aforementioned hydrogen production system via DME steam reforming is to be demonstrated using a thermal power plant. DME steam reforming by using waste heat and the utilization of the produced hydrogen within a combined cycle power plant can reduce fuel consumption, for instance, by about 17% compared to the case of direct DME combustion. The total system, with the use of DME, was compared with the methane case. If necessary, the byproduced CO2 may be injected into coal seams, increasing CH4 production via the substitution of CO2 for CH4 on coal, where CO2 adsorption is expected to be stronger than the CH4 adsorption.

Fukushima, Kimichika; Oota, Hiroyuki; Yamada, Kazuya; Makino, Shinichi; Yagyu, Motoshige; Ikeda, Tatsumi; Asayama, Masahiro; Ogawa, Takashi; Yoshino, Masato

3

The potential of di-methyl ether (DME) as an alternative fuel for compression-ignition engines: A review  

Microsoft Academic Search

This paper reviews the properties and application of di-methyl ether (DME) as a candidate fuel for compression-ignition engines. DME is produced by the conversion of various feedstock such as natural gas, coal, oil residues and bio-mass. To determine the technical feasibility of DME, the review compares its key properties with those of diesel fuel that are relevant to this application.

Constantine Arcoumanis; Choongsik Bae; Roy Crookes; Eiji Kinoshita

2008-01-01

4

Auto-ignition during instationary jet evolution of dimethyl ether (DME) in a high-pressure atmosphere  

SciTech Connect

The auto-ignition process during transient injection of gaseous dimethyl ether (DME) in a constant high-pressure atmosphere is studied experimentally by laser-optical methods and compared with numerical calculations. With different non-intrusive measurement techniques jet properties and auto-ignition are investigated at high temporal and spatial resolution. The open jet penetrates a constant pressure oxidative atmosphere of up to 4 MPa. During the transient evolution, the fuel jet entrains air at up to 720 K. The subsequent auto-ignition of the ignitable part of the jet occurs simultaneously over a wide spatial extension. The ignition delay times are not affected by variation of the nozzle exit velocity. Thus, the low-temperature oxidation is slow compared with the shorter time scales of mixing, so that chemical kinetics is dominating the process. The typical two-stage ignition is resolved optically with high-speed shadowgraphy at a sampling rate of 10 kHz. The 2D fields of jet velocity and transient mixture fraction are measured phase-coupled with Particle Image Velocimetry (PIV) and Tracer Laser Induced Fluorescence (LIF) during the time-frame of ignition. The instationary Probability Density Functions (PDF) of mixture fraction are described very well by Beta functions within the complete area of the open jet. Additional 1D flamelet simulations of the auto-ignition process are computed with a detailed reaction mechanism for DME [S. Fischer, F. Dryer, H. Curran, Int. J. Chem. Kinet. 32 (12) (2000) 713-740; H. Curran, S. Fischer, F. Dryer, Int. J. Chem. Kinet. 32 (12) (2000) 741-759]. Calculated ignition delay times are in very good agreement with the measured mean ignition delay times of 3 ms. Supplemental flamelet simulations address the influence of DME and air temperature, pressure and strain. Underneath a critical strain rate the air temperature is identified to be the most sensitive factor on ignition delay time. (author)

Fast, G.; Kuhn, D.; Class, A.G. [Institut fuer Kern- und Energietechnik, Forschungszentrum Karlsruhe GmbH, Weberstrasse 5, D-76133 Karlsruhe (Germany); Maas, U. [Institut fuer Technische Thermodynamik, Universitat Karlsruhe (TH), Kaiserstrasse 12, D-76128 Karlsruhe (Germany)

2009-01-15

5

Thermodynamic equilibrium calculations of dimethyl ether steam reforming and dimethyl ether hydrolysis  

NASA Astrophysics Data System (ADS)

The production of a hydrogen-rich fuel-cell feed by dimethyl ether (DME) steam reforming was investigated using calculations of thermodynamic equilibrium as a function of steam-to-carbon ratio (0.00-4.00), temperature (100-600 °C), pressure (1-5 atm), and product species. Species considered were acetone, acetylene, carbon dioxide, carbon monoxide, dimethyl ether, ethane, ethanol, ethylene, formaldehyde, formic acid, hydrogen, isopropanol, methane, methanol, methyl-ethyl ether, n-propanol and water. Thermodynamic equilibrium calculations of DME steam reforming indicate complete conversion of dimethyl ether to hydrogen, carbon monoxide and carbon dioxide at temperatures greater than 200 °C and steam-to-carbon ratios greater than 1.25 at atmospheric pressure ( P = 1 atm). Increasing the operating pressure shifts the equilibrium toward the reactants; increasing the pressure from 1 to 5 atm decreases the conversion of dimethyl ether from 99.5 to 76.2%. The trend of thermodynamically stable products in decreasing mole fraction is methane, ethane, isopropyl alcohol, acetone, n-propanol, ethylene, ethanol, methyl-ethyl ether and methanol-formaldehyde, formic acid, and acetylene were not observed. Based on the equilibrium calculations, the optimal processing conditions for dimethyl ether steam reforming occur at a steam-to-carbon ratio of 1.50, a pressure of 1 atm, and a temperature of 200 °C. These thermodynamic equilibrium calculations show dimethyl ether processed with steam will produce hydrogen-rich fuel-cell feeds—with hydrogen concentrations exceeding 70%. The conversion of dimethyl ether via hydrolysis (considering methanol as the only product) is limited by thermodynamic equilibrium. Equilibrium conversion increases with temperature and steam-to-carbon ratio. A maximum dimethyl ether conversion of 62% is achieved at a steam-to-carbon ratio of 5.00 and a processing temperature of 600 °C.

Semelsberger, Troy A.; Borup, Rodney L.

6

An aging study of wire chambers with dimethyl ether  

SciTech Connect

The authors report results on the aging of different types of resistive and non-resistive wires in wire chambers filled with dimethyl ether (DME) of varying degrees of purity. Among the Freon impurities detected in our DME batches, only Freon-11 was found to contribute to the aging process. Of the resistive wires, Nicotin and Stablohm produced fast aging, whereas stainless steel withstood extended irradiation in purified DME (up to 1 C/cm) without any apparent damage. Gold-plated tungsten and molybdenum wires produced results comparable to those of the stainless steel.

Jibaly, M.; Chrusch, P. Jr.; Hilgenberg, G.; Majewski, S.; Wojcik, R.; Sauli, F.; Gaudaen, J.

1989-02-01

7

Synthesis of methyl acetate from syngas via dimethyl ether  

SciTech Connect

Dimethyl ether (DME) can be used as a building block for a variety of specialty chemicals in the petrochemical industry. Its utilization stems mainly from its efficient production from synthesis gas in a single stage. This Liquid Phase Dimethyl Ether (LP-DME) process, based on dual catalysts slurried in inert oil, can alleviate the chemical equilibrium limitation governing the methanol synthesis reaction and concurrently improve once-through syngas conversion and reactor productivity. Studies in the past have focused on using DME as a feedstock for gasoline range hydrocarbons as well as lower olefins. The focus of this investigation is to study the synthesis of methyl acetate, an important intermediate for acetic acid, from dimethyl ether. In particular, conversion of DME to methyl acetate is investigated over a variety of Group VIII metal substituted phosphotungstic acid salts. Key aspects of the process such as the effect of active metal, support types, multiple metal loading, and feed conditions are examined. Thus, this paper introduces a novel process route for synthesis of methyl acetate from natural gas-based syngas via dimethyl ether as an intermediate.

Tartamella, T.; Sardesai, A.; Lanterman, H.B.; Lee, S.

1999-07-01

8

DOI: 10.1002/cctc.201000383 Catalytic Co-Homologation of Alkanes and Dimethyl Ether  

E-print Network

DOI: 10.1002/cctc.201000383 Catalytic Co-Homologation of Alkanes and Dimethyl Ether and Promotion reactions to form alkanes. Alkoxides can desorb as alkenes, which can undergo subse- quent methylation for the co-homologa- tion of linear and branched alkanes with dimethyl ether (DME) to form larger branched

Iglesia, Enrique

9

Syngas to olefins via dimethyl ether over zeolite catalysts  

SciTech Connect

Coal or natural gas-based syngas can be converted to dimethyl ether (DME) in a dual catalytic, single-stage liquid phase process. The process described here converts dimethyl ether to lower olefins, such as ethylene, propylene, and butenes. Thus, a novel process of producing olefins from syngas via dimethyl ether has been introduced. The process feasibility of dimethyl ether conversion has been evaluated and the range of products of this process has also been identified. The effect of operating parameters and catalyst characteristics on product selectivity has been studied. The superior process advantages as well as its competitive economics quite clearly identify this process to be quite promising when conducted on an industrial scale.

Lee, B.G. [Korea Inst. of Science and Technology, Seoul (Korea, Republic of); Sardesai, A.; Lee, S. [Univ. of Missouri, Columbia, MO (United States). Dept. of Chemical Engineering

1998-12-31

10

Extraction of PCBs and water from river sediment using liquefied dimethyl ether as an extractant.  

PubMed

We investigated whether polychlorinated biphenyls (PCBs) and water could be simultaneously removed from river sediment by solvent extraction using liquefied dimethyl ether (DME) as the extractant. DME exists in a gaseous state at normal temperature and pressure and can dissolve organic substances and some amount of water; therefore, liquefied DME under moderate pressure (0.6-0.8 MPa) at room temperature can be effectively used to extract PCBs and water from contaminated sediment, and it can be recovered from the extract and reused easily. First, we evaluated the PCB and water extraction characteristics of DME from contaminated sediment. We found that 99% of PCBs and 97% of water were simultaneously extracted from the sediment using liquefied DME at an extraction time of 4320 s and a liquefied DME/sediment ratio of 60 mL g(-1). The extraction rate of PCBs and water was expressed in terms of a pseudo-first-order reaction rate. Second, we estimated the amount of DME that was recovered after extraction. We found that 91-92% of DME could be recovered. In other words, approximately 5-10% of DME was lost during extraction and recovery. It is necessary to optimize this process in order to recover DME efficiently. The extraction efficiency of the recovered DME is similar to that of the pure DME. From the results, we conclude that solvent extraction using liquefied DME is suitable for extracting PCBs and water from contaminated sediment. PMID:20044120

Oshita, Kazuyuki; Takaoka, Masaki; Kitade, Sin-ichiro; Takeda, Nobuo; Kanda, Hideki; Makino, Hisao; Matsumoto, Tadao; Morisawa, Shinsuke

2010-02-01

11

Dimethyl ether (DME) as an alternative fuel  

Microsoft Academic Search

With ever growing concerns on environmental pollution, energy security, and future oil supplies, the global community is seeking non-petroleum based alternative fuels, along with more advanced energy technologies (e.g., fuel cells) to increase the efficiency of energy use. The most promising alternative fuel will be the fuel that has the greatest impact on society. The major impact areas include well-to-wheel

Troy A. Semelsberger; Rodney L. Borup; Howard L. Greene

2006-01-01

12

Insight into Selected Reactions in Low-Temperature Dimethyl Ether Combustion from Born-Oppenheimer Molecular Dynamics  

E-print Network

; In Final Form: October 28, 2005 Dimethyl ether is under consideration as an alternative diesel fuel. Its for conventional diesel fuel. DME's propensity to compression ignite is comparable to that of conventional diesel fuel, which is comprised of long-chain hydrocarbons. Unlike conventional diesel fuel, DME creates

Carter, Emily A.

13

Evaluation of methyl fluoride and dimethyl ether as inhibitors of aerobic methane oxidation  

USGS Publications Warehouse

Methyl fluoride (MF) and dimethyl ether (DME) were effective inhibitors of aerobic methanotrophy in a variety of soils. MF and DME blocked consumption of CH4 as well as the oxidation of 14CH4 to 14CO2, but neither MF nor DME affected the oxidation of [14C]methanol or [14C]formate to 14CO2. Cooxidation of ethane and propane by methane-oxidizing soils was also inhibited by MF. Nitrification (ammonia oxidation) in soils was inhibited by both MF and DME. Production of N2O via nitrification was inhibited by MF; however, MF did not affect N2O production associated with denitrification. Methanogenesis was partially inhibited by MF but not by DME. Methane oxidation was ~100-fold more sensitive to MF than was methanogenesis, indicating that an optimum concentration could be employed to selectively block methanotrophy. MF inhibited methane oxidation by cell suspensions of Methylococcus capsulatus; however, DME was a much less effective inhibitor.

Oremland, R.S.; Culbertson, C.W.

1992-01-01

14

Radio detection of interstellar dimethyl ether  

NASA Technical Reports Server (NTRS)

The detection of interstellar dimethyl ether, in emission from the direction of the Orion Nebula molecular cloud, is reported. The largest molecule detected in space, dimethyl ether has a large collisional cross section and C (sub 2V) symmetry. Hence, it should be useful for future studies of molecular pumping models.

Snyder, L. E.; Buhl, D.; Schwartz, P. R.; Clark, F. O.; Johnson, D. R.; Lovas, F. J.; Giguere, P. T.

1974-01-01

15

Thermodynamics of Hydrogen Production from Dimethyl Ether Steam Reforming and Hydrolysis  

SciTech Connect

The thermodynamic analyses of producing a hydrogen-rich fuel-cell feed from the process of dimethyl ether (DME) steam reforming were investigated as a function of steam-to-carbon ratio (0-4), temperature (100 C-600 C), pressure (1-5 atm), and product species: acetylene, ethanol, methanol, ethylene, methyl-ethyl ether, formaldehyde, formic acid, acetone, n-propanol, ethane and isopropyl alcohol. Results of the thermodynamic processing of dimethyl ether with steam indicate the complete conversion of dimethyl ether to hydrogen, carbon monoxide and carbon dioxide for temperatures greater than 200 C and steam-to-carbon ratios greater than 1.25 at atmospheric pressure (P = 1 atm). Increasing the operating pressure was observed to shift the equilibrium toward the reactants; increasing the pressure from 1 atm to 5 atm decreased the conversion of dimethyl ether from 99.5% to 76.2%. The order of thermodynamically stable products in decreasing mole fraction was methane, ethane, isopropyl alcohol, acetone, n-propanol, ethylene, ethanol, methyl-ethyl ether and methanol--formaldehyde, formic acid, and acetylene were not observed. The optimal processing conditions for dimethyl ether steam reforming occurred at a steam-to-carbon ratio of 1.5, a pressure of 1 atm, and a temperature of 200 C. Modeling the thermodynamics of dimethyl ether hydrolysis (with methanol as the only product considered), the equilibrium conversion of dimethyl ether is limited. The equilibrium conversion was observed to increase with temperature and steam-to-carbon ratio, resulting in a maximum dimethyl ether conversion of approximately 68% at a steam-to-carbon ratio of 4.5 and a processing temperature of 600 C. Thermodynamically, dimethyl ether processed with steam can produce hydrogen-rich fuel-cell feeds--with hydrogen concentrations exceeding 70%. This substantiates dimethyl ether as a viable source of hydrogen for PEM fuel cells.

T.A. Semelsberger

2004-10-01

16

Adsorption structure of dimethyl ether on silicalite-1 zeolite determined using single-crystal X-ray diffraction  

PubMed Central

The adsorption structures of dimethyl ether (DME) on silicalite-1 zeolite (MFI-type) are determined using single-crystal X-ray diffraction. The structure of low-loaded DME-silicalite-1 indicates that all DME molecules are located in the sinusoidal channel, which is the most stable sorption site based on the van der Waals interaction between DME and the framework. The configuration of guest molecules (linear or bent) plays an important role in determining where the stable sorption site is in the pore system of MFI-type zeolites. Bent molecules favor the sinusoidal channel, while linear molecules favor the straight channel. The contribution of DME–DME interactions is considerable in the high-loaded DME-silicalite-1 structure. PMID:25274519

Fujiyama, Shinjiro; Seino, Shintaro; Kamiya, Natsumi; Nishi, Koji; Yokomori, Yoshinobu

2014-01-01

17

Wide range modeling study of dimethyl ether oxidation  

SciTech Connect

A detailed chemical kinetic model has been used to study dimethyl ether (DME) oxidation over a wide range of conditions. Experimental results obtained in a jet-stirred reactor (JSR) at I and 10 atm, 0.2 < 0 < 2.5, and 800 < T < 1300 K were modeled, in addition to those generated in a shock tube at 13 and 40 bar, 0 = 1.0 and 650 :5 T :5 1300 K. The JSR results are particularly valuable as they include concentration profiles of reactants, intermediates and products pertinent to the oxidation of DME. These data test the Idnetic model severely, as it must be able to predict the correct distribution and concentrations of intermediate and final products formed in the oxidation process. Additionally, the shock tube results are very useful, as they were taken at low temperatures and at high pressures, and thus undergo negative temperature dependence (NTC) behavior. This behavior is characteristic of the oxidation of saturated hydrocarbon fuels, (e.g. the primary reference fuels, n-heptane and iso- octane) under similar conditions. The numerical model consists of 78 chemical species and 336 chemical reactions. The thermodynamic properties of unknown species pertaining to DME oxidation were calculated using THERM.

Pitz, W.J.; Marinov, N.M.; Westbrook, C.K.; Dagaut, P.; Boettner, J-C; Cathonnet, M.

1997-04-01

18

Dehydration of methanol to dimethyl ether over nanocrystalline Al 2O 3 with mixed ?- and ?-crystalline phases  

Microsoft Academic Search

Dehydration of methanol to dimethyl ether (DME) was investigated over a wide range of nanocrystalline Al2O3 with mixed ?- and ?-crystalline phases. The catalysts were characterized by X-ray diffraction (XRD), N2 physisorption, ion-exchange titration, and NH3-tempearture programmed desorption (NH3-TPD). It was found that ?-Al2O3 catalyst containing 20wt% of ?-phase exhibited the highest yield (86%) with good stability for DME synthesis.

Piyasan Praserthdam; Joongjai Panpranot; Okorn Mekasuwandumrong

2008-01-01

19

Dimethyl ether oxidation at elevated temperatures (295-600 K).  

PubMed

Dimethyl ether (DME) has been proposed for use as an alternative fuel or additive in diesel engines and as a potential fuel in solid oxide fuel cells. The oxidation chemistry of DME is a key element in understanding its role in these applications. The reaction between methoxymethyl radicals and O(2) has been examined over the temperature range 295-600 K and at pressures of 20-200 Torr. This reaction has two product pathways. The first produces methoxymethyl peroxy radicals, while the second produces OH radicals and formaldehyde molecules. Real-time kinetic measurements are made by transient infrared spectroscopy to monitor the yield of three main products-formaldehyde, methyl formate, and formic acid-to determine the branching ratio for the CH(3)OCH(2) + O(2) reaction pathways. The temperature and pressure dependence of this reaction is described by a Lindemann and Arrhenius mechanism. The branching ratio is described by f = 1/(1 + A(T)[M]), where A(T) = (1.6(+2.4)(-1.0) x 10(-20)) exp((1800 +/- 400)/T) cm(3) molecule(-1). The temperature dependent rate constant of the methoxymethyl peroxy radical self-reaction is calculated from the kinetics of the formaldehyde and methyl formate product yields, k(4) = (3.0 +/- 2.1) x 10(-13) exp((700 +/- 250)/T) cm(3) molecule(-1) s(-1). The experimental and kinetics modeling results support a strong preference for the thermal decomposition of alkoxy radicals versus their reaction with O(2) under our laboratory conditions. These characteristics of DME oxidation with respect to temperature and pressure might provide insight into optimizing solid oxide fuel cell operating conditions with DME in the presence of O(2) to maximize power outputs. PMID:16331938

Rosado-Reyes, Claudette M; Francisco, Joseph S; Szente, Joseph J; Maricq, M Matti; Frøsig Østergaard, Lars

2005-12-01

20

Production of hydrogen-rich gas by plasma reforming of dimethyl ether  

Microsoft Academic Search

The production of hydrogen-rich gas by plasma reforming of dimethyl ether (DME) was conducted in a self-made three-cavity reformer at atmospheric pressure and ambient temperature. The effects of reformer structure parameters, electrode material, heat transfer characteristics, and operation parameters on the gas composition and hydrogen yield were investigated. The results indicated that the yield of hydrogen increases with the increase

Kui-feng MA; Xing-hu LI

2010-01-01

21

Use of aluminum phosphate as the dehydration catalyst in single step dimethyl ether process  

DOEpatents

The present invention pertains to a process for the coproduction of methanol and dimethyl ether (DME) directly from a synthesis gas in a single step (hereafter, the "single step DME process"). In this process, the synthesis gas comprising hydrogen and carbon oxides is contacted with a dual catalyst system comprising a physical mixture of a methanol synthesis catalyst and a methanol dehydration catalyst. The present invention is an improvement to this process for providing an active and stable catalyst system. The improvement comprises the use of an aluminum phosphate based catalyst as the methanol dehydration catalyst. Due to its moderate acidity, such a catalyst avoids the coke formation and catalyst interaction problems associated with the conventional dual catalyst systems taught for the single step DME process.

Peng, Xiang-Dong (Allentown, PA); Parris, Gene E. (Coopersburg, PA); Toseland, Bernard A. (Allentown, PA); Battavio, Paula J. (Allentown, PA)

1998-01-01

22

CATALYST ACTIVITY MAINTENANCE FOR THE LIQUID PHASE SYNTHESIS GAS-TO-DIMETHYL ETHER PROCESS PART II: DEVELOPMENT OF ALUMINUM PHOSPHATE AS THE DEHYDRATION CATALYST FOR THE SINGLE-STEP LIQUID PHASE SYNGAS-TO-DME PROCESS  

SciTech Connect

At the heart of the single-step liquid phase syngas-to-DME process (LPDME{trademark}) is a catalyst system that can be active as well as stable. In the Alternative Fuels I program, a dual-catalyst system containing a Cu-based commercial methanol synthesis catalyst (BASF S3-86) and a commercial dehydration material ({gamma}-alumina) was demonstrated. It provided the productivity and selectivity expected from the LPDME process. However, the catalyst system deactivated too rapidly to warrant a viable commercial process [1]. The mechanistic investigation in the early part of the DOE's Alternative Fuels II program revealed that the accelerated catalyst deactivation under LPDME conditions is due to detrimental interaction between the methanol synthesis catalyst and methanol dehydration catalyst [2,3]. The interaction was attributed to migration of Cu- and/or Zn-containing species from the synthesis catalyst to the dehydration catalyst. Identification of a dehydration catalyst that did not lead to this detrimental interaction while retaining adequate dehydration activity was elusive. Twenty-nine different dehydration materials were tested, but none showed the desired performance [2]. The search came to a turning point when aluminum phosphate was tested. This amorphous material is prepared by precipitating a solution containing Al(NO{sub 3}){sub 3} and H{sub 3}PO{sub 4} with NH{sub 4}OH, followed by washing, drying and calcination. The aluminum phosphate catalyst has adequate dehydration activity and good stability. It can co-exist with the Cu-based methanol synthesis catalyst without negatively affecting the latter catalyst's stability. This report documents the details of the development of this catalyst. These include initial leads, efforts in improving activity and stability, investigation and development of the best preparation parameters and procedures, mechanistic understanding and resulting preparation guidelines, and the accomplishments of this work.

Xiang-Dong Peng

2002-05-01

23

Synergistic effect of mixing dimethyl ether with methane, ethane, propane, and ethylene fuels on polycyclic aromatic hydrocarbon and soot formation  

SciTech Connect

Characteristics of polycyclic aromatic hydrocarbon (PAH) and soot formation in counterflow diffusion flames of methane, ethane, propane, and ethylene fuels mixed with dimethyl ether (DME) have been investigated. Planar laser-induced incandescence and fluorescence techniques were employed to measure relative soot volume fractions and PAH concentrations, respectively. Results showed that even though DME is known to be a clean fuel in terms of soot formation, DME mixture with ethylene fuel increases PAH and soot formation significantly as compared to the pure ethylene case, while the mixture of DME with methane, ethane, and propane decreases PAH and soot formation. Numerical calculations adopting a detailed kinetics showed that DME can be decomposed to produce a relatively large number of methyl radicals in the low-temperature region where PAH forms and grows; thus the mixture of DME with ethylene increases CH{sub 3} radicals significantly in the PAH formation region. Considering that the increase in the concentration of O radicals is minimal in the PAH formation region with DME mixture, the enhancement of PAH and soot formation in the mixture flames of DME and ethylene can be explained based on the role of methyl radicals in PAH and soot formation. Methyl radicals can increase the concentration of propargyls, which could enhance incipient benzene ring formation through the propargyl recombination reaction and subsequent PAH growth. Thus, the result substantiates the importance of methyl radicals in PAH and soot formation, especially in the PAH formation region of diffusion flames. (author)

Yoon, S.S. [Corporate Research and Development Division, Hyundai-Kia Motors, Gyeonggi-do 445-706 (Korea); Anh, D.H. [Korea Electric Power Research Institute, Daejeon 305-380 (Korea); Chung, S.H. [School of Mechanical and Aerospace Engineering, Seoul National University, Seoul 151-742 (Korea)

2008-08-15

24

Process for producing dimethyl ether form synthesis gas  

DOEpatents

This invention pertains to a Fischer Tropsch process for converting synthesis gas to an oxygenated hydrocarbon with particular emphasis on dimethyl ether. Synthesis gas comprising carbon monoxide and hydrogen are converted to dimethyl ether by carrying out the reaction in the presence of an alkali metal-manganese-iron carbonyl cluster incorporated onto a zirconia-alumina support.

Pierantozzi, Ronald (Macungie, PA)

1985-01-01

25

Process for producing dimethyl ether from synthesis gas  

DOEpatents

This invention pertains to a Fischer Tropsch process for converting synthesis gas to an oxygenated hydrocarbon with particular emphasis on dimethyl ether. Synthesis gas comprising carbon monoxide and hydrogen are converted to dimethyl ether by carrying out the reaction in the presence of an alkali metal-manganese-iron carbonyl cluster incorporated onto a zirconia-alumina support.

Pierantozzi, R.

1985-06-04

26

Chapter 25 First-Principles Investigation of Dimethyl Ether Steam Reforming  

NASA Astrophysics Data System (ADS)

This paper reports the investigation of dimethyl ether (DME) steam reforming and related processes. The study uses the X[alpha] molecular orbital theory, which has been successfully applied to analyze material properties. It was found that, when H2O approaches Al on a surface of Si oxides (and pure Al2O3), charge transfer between H2O and the surface destabilizes the H2O. Approach of the destabilized H to a CH3OCH3 molecule then produces CH3OH. Finally, injection of CO2, by-produced in the reforming, to coal seam was shown to increase the CH4 production by substitution.

Fukushima, Kimichika

27

Using Heteropolyacids in the Anode Catalyst Layer of Dimethyl Ether PEM Fuel Cells  

SciTech Connect

In this study, polarization experiments were performed on a direct dimethyl ether fuel cell (DMEFC). The experimental setup allowed for independent control of water and DME flow rates. Thus the DME flow rate, backpressure, and water flow rate were optimized. Three heteropoly acids, phosphomolybdic acid (PMA), phosphotungstic acid (PTA), and silicotungstic acid (STA) were incorporated into the anode catalyst layer in combination with Pt/C. Both PTA-Pt and STA-Pt showed higher performance than the Pt control at 30 psig of backpressure. Anodic polarizations were also performed, and Tafel slopes were extracted from the data. The trends in the Tafel slope values are in agreement with the polarization data. The addition of phosphotungstic acid more than doubled the power density of the fuel cell, compared to the Pt control.

Ferrell III, J. R.; Turner, J. A.; Herring, A. M.

2008-01-01

28

Extraction of fucoxanthin from raw macroalgae excluding drying and cell wall disruption by liquefied dimethyl ether.  

PubMed

Macroalgae are one of potential sources for carotenoids, such as fucoxanthin, which are consumed by humans and animals. This carotenoid has been applied in both the pharmaceutical and food industries. In this study, extraction of fucoxanthin from wet brown seaweed Undaria pinnatifida (water content was 93.2%) was carried out with a simple method using liquefied dimethyl ether (DME) as an extractant in semi-continuous flow-type system. The extraction temperature and absolute pressure were 25 °C and 0.59 MPa, respectively. The liquefied DME was passed through the extractor that filled by U. pinnatifida at different time intervals. The time of experiment was only 43 min. The amount of fucoxanthin could approach to 390 ?g/g dry of wet U. pinnatifida when the amount of DME used was 286 g. Compared with ethanol Soxhlet and supercritical CO? extraction, which includes drying and cell disruption, the result was quite high. Thus, DME extraction process appears to be a good method for fucoxanthin recovery from U. pinnatifida with improved yields. PMID:24796299

Kanda, Hideki; Kamo, Yuichi; Machmudah, Siti; Wahyudiono, Emptyyn Y; Goto, Motonobu

2014-05-01

29

Isotopic studies and refined structure for the dimethyl ether-CS 2 dimer  

NASA Astrophysics Data System (ADS)

Rotational spectra of two additional isotopomers of the 1:1 dimer between dimethyl ether (DME) and carbon disulfide (CS 2) have been measured by Fourier-transform microwave spectroscopy, allowing an inertial fit of the structure of this complex. The isotopic data are consistent with a structure in which the CS 2 is aligned nearly perpendicular to the plane of the heavy atoms in DME, with internal motion of the CS 2 from one side of the DME to the other leading to an inversion splitting, ? E, of 90.34 MHz. This corresponds to a barrier to the tunneling motion of 69(10) cm -1. Ab initio calculations give two structures that are fairly consistent with the experimental rotational constants. One of these is similar to the experimental structure derived from the moments of inertia of three isotopic species, while in the other the CS 2 is aligned roughly along the lone pair direction of the DME, similar to previously observed hydrogen bonded complexes.

Peebles, Sean A.; Peebles, Rebecca A.

2007-03-01

30

Extraction of Fucoxanthin from Raw Macroalgae excluding Drying and Cell Wall Disruption by Liquefied Dimethyl Ether  

PubMed Central

Macroalgae are one of potential sources for carotenoids, such as fucoxanthin, which are consumed by humans and animals. This carotenoid has been applied in both the pharmaceutical and food industries. In this study, extraction of fucoxanthin from wet brown seaweed Undaria pinnatifida (water content was 93.2%) was carried out with a simple method using liquefied dimethyl ether (DME) as an extractant in semi-continuous flow-type system. The extraction temperature and absolute pressure were 25 °C and 0.59 MPa, respectively. The liquefied DME was passed through the extractor that filled by U. pinnatifida at different time intervals. The time of experiment was only 43 min. The amount of fucoxanthin could approach to 390 ?g/g dry of wet U. pinnatifida when the amount of DME used was 286 g. Compared with ethanol Soxhlet and supercritical CO2 extraction, which includes drying and cell disruption, the result was quite high. Thus, DME extraction process appears to be a good method for fucoxanthin recovery from U. pinnatifida with improved yields. PMID:24796299

Kanda, Hideki; Kamo, Yuichi; Machmudah, Siti; Wahyudiono; Goto, Motonobu

2014-01-01

31

Performance Estimation of Absorption/Compression Cycle Using Working Pair Dimethyle Ether/Methanol  

NASA Astrophysics Data System (ADS)

This paper presents the performance estimation of hybrid absorption/compression heat pump cycle, which use dimethyl ether (DME) and methanol pair as a working fluid. The disadvantage of the DME as a refrigerant is that it is flammable. But it has several advantages from the environmental aspects; toxicity is very low, and GWP is small. The first purpose of this study is to estimate the reduction of the loss of the heat exchangers, by use of absorption/compression cycle. And the second purpose is to lower the working pressure to reduce the possibility of the leakage of the working fluids. Two hybrid systems are supposed as models; one is absorption/compression system with single stage solution circuit, and another is an absorption/compression system with generator/absorber heat exchange cycle. The former cycle exceeds the cooling and heating COPs of pure DME cycle, reducing the maximum pressure about 130 kPa. And the latter system increases the heating COP by 6 to 36% with the working pressure range about 150-260 kPa.

Endo, Naok; Maeda, Tetsuhiko; Hasegawa, Yasuo

32

Study on systems based on coal and natural gas for producing dimethyl ether  

SciTech Connect

China is a coal-dependent country and will remain so for a long time. Dimethyl ether (DME), a potential substitute for liquid fuel, is a kind of clean diesel motor fuel. The production of DME from coal is meaningful and is studied in this article. Considering the C/H ratios of coal and natural gas (NG), the cofeed (coal and NG) system (CFS), which does not contain the water gas shift process, is studied. It can reduce CO{sub 2} emission and increase the conversion rate of carbon, producing more DME. The CFS is simulated and compared with the coal-based and NG-based systems with different recycling ratios. The part of the exhaust gas that is not recycled is burned, producing electricity. On the basis of the simulation results, the thermal efficiency, economic index, and CO{sub 2} emission ratio are calculated separately. The CFS with a 100% recycling ratio has the best comprehensive evaluation index, while the energy, economy, and environment were considered at the same time.

Zhou, L.; Hu, S.Y.; Chen, D.J.; Li, Y.R.; Zhu, B.; Jin, Y. [Tsinghua University, Beijing (China). Dept. of Chemical Engineering

2009-04-15

33

Selective inhibition of ammonium oxidation and nitrification-linked N2O formation by methyl fluoride and dimethyl ether  

USGS Publications Warehouse

Methyl fluoride (CH3F) and dimethyl ether (DME) inhibited nitrification in washed-cell suspensions of Nitrosomonas europaea and in a variety of oxygenated soils and sediments. Headspace additions of CH3F (10% [vol/vol]) and DME (25% [vol/vol]) fully inhibited NO2- and N2O production from NH4+ in incubations of N. europaea, while lower concentrations of these gases resulted in partial inhibition. Oxidation of hydroxylamine (NH2OH) by N. europaea and oxidation of NO2- by a Nitrobacter sp. were unaffected by CH3F or DME. In nitrifying soils, CH3F and DME inhibited N2O production. In field experiments with surface flux chambers and intact cores, CH3F reduced the release of N2O from soils to the atmosphere by 20- to 30-fold. Inhibition by CH3F also resulted in decreased NO3- + NO2- levels and increased NH4+ levels in soils. CH3F did not affect patterns of dissimilatory nitrate reduction to ammonia in cell suspensions of a nitrate- respiring bacterium, nor did it affect N2O metabolism in denitrifying soils. CH3F and DME will be useful in discriminating N2O production via nitrification and denitrification when both processes occur and in decoupling these processes by blocking NO2- and NO3- production.

Miller, L.G.; Coutlakis, M.D.; Oremland, R.S.; Ward, B.B.

1993-01-01

34

Torsionally Excited Dimethyl Ether in the Laboratory and in Space  

NASA Astrophysics Data System (ADS)

Dimethyl ether (DME) is highly abundant in hot cores and numerous transitions within the vibrational ground state have been detected in various interstellar line surveys of sources such as Orion KL. As a nearly prolate asymmetric top with two internal rotors, it shows a complex spectrum with low lying torsional modes. The energy levels of the two lowest torsional states (v11, and v15) lie only 200 and 240 cm-1 above the ground state (barrier height ? 915 cm-1), and are thus sufficiently populated in these interstellar sources to exhibit transitions in line surveys due to high excitation temperatures in hot cores. So far, the lack of sufficiently accurate predictions for the two lowest excited torsional states prevented their identification in astronomical spectra. Therefore, we analyzed spectra, which have been recorded within the context of the investigations of the ground state. In total, more than 9500 transitions have been assigned covering the frequency range from 38 up to 1670 GHz. The enlarged splitting of each rotational level into four substates (AA, EE, AE, EA) compared to its size in the ground state and a large number of perturbed transitions hampered not only the line assignment but also the astrophysical modelling. However, the inclusion of interaction terms between both excited states in the model of an effective Hamiltonian for a symmetric two-top rotor, allowed us to model both excited states within a global fit, and also to accurately determine the energy difference between both states. Frequency predictions have been calculated based on this analysis and have been used to unambiguously assign numerous rotational transitions within these excited states in the astronomical line survey of the hot core region G327.3-0.6. P. Schilke, T.D. Groesbeck et al., Astrophys.J.Suppl.Ser., 108,(1997) 301-337 P. Schilke, D.J. Benford, T.R. Hunter et al., Astrophys.J.Suppl.Ser., 132,(2001) 281-364. P. Groner, S. Albert, E. Herbst, and F.C. De Lucia, Astrophys. J., 500, (1998) 1059-1063 C.P. Endres, B.J. Drouin et al., Astronom.Astrophys., 504, (2009) 635-640

Endres, C. P.; Müller, H. S. P.; Lewen, F.; Giesen, T. F.; Schlemmer, S.; Drouin, B. J.; Bisschop, S.; Groner, P.

2010-06-01

35

Experimental and Computational Study of Nonpremixed Ignition of Dimethyl Ether in Counterflow  

SciTech Connect

The ignition temperature of nitrogen-diluted dimethyl ether (DME) by heated air in counterflow was experimentally determined for DME concentration from 5.9 to 30%, system pressure from 1.5 to 3.0 atmospheres, and pressure-weighted strain rate from 110 to 170/s. These experimental data were compared with two mechanisms that were respectively available in 1998 and 2003, with the latter being a substantially updated version of the former. The comparison showed that while the 1998-mechanism uniformly over-predicted the ignition temperature, the 2003-mechanism yielded surprisingly close agreement for all experimental data. Sensitivity analysis for the near-ignition state based on both mechanisms identified the deficiencies of the 1998-mechanism, particularly the specifics of the low-temperature cool flame chemistry in effecting ignition at higher temperatures, as the fuel stream is being progressively heated from its cold boundary to the high-temperature ignition region around the hot-stream boundary. The 2003-mechanism, consisting of 79 species and 398 elementary reactions, was then systematically simplified by using the directed relation graph method to a skeletal mechanism of 49 species and 251 elementary reactions, which in turn was further simplified by using computational singular perturbation method and quasi-steady-state species assumption to a reduced mechanism consisting of 33 species and 28 lumped reactions. It was demonstrated that both the skeletal and reduced mechanisms mimicked the performance of the detailed mechanism with high accuracy.

Zheng, X L; Lu, T F; Law, C K; Westbrook, C K

2003-12-19

36

The Concept and experimental results of low compression Ratio DME engines operated at stoichiometric working gas  

Microsoft Academic Search

Among a lot of benefits of Dimethyl Ether (DME) as an alternative fuel, the combustion characteristic for diesel engines, are high cetane number and no soot combustion.The high cetane number of DME enables to operate the low compression ratio engines produced for spark ignition engines designed for a direct gasoline injection. And no soot combustion enables to operate engines at

Shuichi KAJITANI; Masayuki TAKEDA; Atushi HOSHIYAMA; Masaaki KATO

37

Synthesis of Methanol and Dimethyl Ether from Syngas over Pd/ZnO/Al2O3 Catalysts  

SciTech Connect

A Pd/ZnO/Al2O3 catalyst was developed for the synthesis of methanol and dimethyl ether (DME) from syngas. Studied were temperatures of operation ranging from 250°C to 380°C. High temperatures (e.g. 380°C) are necessary when combining methanol and DME synthesis with a methanol to gasoline (MTG) process in a single reactor bed. A commercial Cu/ZnO/Al2O3 catalyst, utilized industrially for the synthesis of methanol at 220-280°C, suffers from a rapid deactivation when the reaction is conducted at high temperature (>320°C). On the contrary, a Pd/ZnO/Al2O3 catalyst was found to be highly stable for methanol and DME synthesis at 380°C. The Pd/ZnO/Al2O3 catalyst was thus further investigated for methanol and DME synthesis at P=34-69 bars, T= 250-380°C, GHSV= 5 000-18 000 h-1, and molar feeds H2/CO= 1, 2, and 3. Selectivity to DME increased with decreasing operating temperature, and increasing operating pressure. Increased GHSV’s and H2/CO syngas feed ratios also enhanced DME selectivity. Undesirable CH4 formation was observed, however, can be minimized through choice of process conditions and by catalyst design. By studying the effect of the Pd loading and the Pd:Zn molar ratio the formulation of the Pd/ZnO/Al2O3 catalyst was optimized. A catalyst with 5% Pd and a Pd:Zn molar ratio of 0.25:1 has been identified as the preferred catalyst. Results indicate that PdZn particles are more active than Pdº particles for the synthesis of methanol and less active for CH4 formation. A correlation between DME selectivity and the concentration of acid sites of the catalysts has been established. Hence, two types of sites are required for the direct conversion of syngas to DME: 1) PdZn particles are active for the synthesis of methanol from syngas, and 2) acid sites which are active for the conversion of methanol to DME. Additionally, CO2 formation was problematic as PdZn was found to be active for the water-gas-shift (WGS) reaction, under all the conditions evaluated.

Lebarbier, Vanessa MC; Dagle, Robert A.; Kovarik, Libor; Lizarazo Adarme, Jair A.; King, David L.; Palo, Daniel R.

2012-10-01

38

The Microwave Spectrum of Partially Deuterated Species of Dimethyl Ether  

NASA Astrophysics Data System (ADS)

Dimethyl ether is a molecule of astrophysical interest spectroscopically well characterized. It is one of the simplest molecules with two methyl groups undergoing large amplitude internal rotations. Due to deuterium enrichment in the interstellar medium, one can reasonably expect that partially deuterated species of dimethyl ether might be detected. However, there are no spectroscopic results about the microwave spectrum of such species. A theoretical calculation of the rotation-torsion energy levels of the partially deuterated species of dimethyl ether has been undertaken aided by ab initio calculations. The approach accounts for the complicated torsion-rotation interactions displayed by this molecule and for the fact that deuteration leads to changes of the bidimensional internal rotation effective potential energy surface. Due to zero-point energy contributions from the 19 small amplitude vibrational modes, this surface no longer displays G36 symmetry. Rotation-torsion energy levels are computed treating the two angles of internal rotation as active coordinates and evaluating Hamiltonian matrix elements with the help of Gaussian quadrature. It is hoped that the present results will allow us to understand the microwave spectrum of the mono deuterated species CH_2DOCH_3 which has been recorded in Lille with the new sub millimeter wave spectrometer (150--950 GHz) based on harmonic generation of solid-state sources. [2] Snyder, Buhl, and Schwartz, Astrophys. J. Letters 191 (1974) L79. [3] Endres, Drouin, Pearson, Müller, Lewen, Schlemmer, and Giesen, A&A 504 (2009) 635. [4] Solomon and Woolf, Astrophys. J. Letters 180 (1973) L89. [5] Lauvergnat and Nauts, J. Chem. Phys. 116 (2002) 8560; and Light and Ba?i?, J. Chem. Phys. 87 (1987) 4008.

Lauvergnat, D.; Margulès, L.; Motiyenko, R. A.; Guillemin, J.-C.; Coudert, L. H.

2011-06-01

39

IMPACT OF DME-DIESEL FUEL BLEND PROPERTIES ON DIESEL FUEL INJECTION SYSTEMS  

SciTech Connect

The objectives of this research program are to develop information on lubricity and viscosity improvers and their impact on the wear mechanisms in fuel injectors operating on blends of dimethyl ether (DME) and diesel fuel. This project complements another ongoing project titled ''Development of a Dimethyl Ether (DME)-Fueled Shuttle Bus Demonstration Project''. The objectives of that research and demonstration program are to convert a campus shuttle bus to operation on dimethyl ether, a potential ultra-clean alternative diesel fuel. To accomplish this objective, this project includes laboratory evaluation of a fuel conversion strategy, as well as, field demonstration of the DME-fueled shuttle bus. Since DME is a fuel with no lubricity (i.e., it does not possess the lubricating quality of diesel fuel), conventional fuel delivery and fuel injection systems are not compatible with dimethyl ether. Therefore, to operate a diesel engine on DME one must develop a fuel-tolerant injection system, or find a way to provide the necessary lubricity to the DME. In the shuttle bus project, they have chosen the latter strategy in order to achieve the objective with minimal need to modify the engine. The strategy is to blend DME with diesel fuel, to obtain the necessary lubricity to protect the fuel injection system and to achieve low emissions. In this project, they have sought to develop methods for extending the permissible DME content in the DME-diesel blends without experiencing rapid injector failure due to wear. To date, the activities have covered two areas: development of a high-pressure lubricity test apparatus for studies of lubricity and viscosity improvers and development of an injector durability stand for evaluation of wear rates in fuel injectors. This report provides summaries of the progress toward completion of both experimental systems and a summary of the plan for completion of the project objectives.

Elana M. Chapman; Andre L. Boehman; Kimberly Wain; Wallis Lloyd; Joseph M. Perez; Donald Stiver; Joseph Conway

2002-07-01

40

Rate Constants for the Reactions of Hydroxyl Radical with Several Alkanes, Cycloalkanes, and Dimethyl Ether  

NASA Technical Reports Server (NTRS)

Relative rate experiements were used to measure rate constants and temperature denpendencies of the reactions of OH with propane, n-butane, n-pentane, n-hexane, cyclopropane, cyclobutane, cyclopentane, and dimethyl ether.

DeMore, W.; Bayes, K.

1998-01-01

41

Experimental research on flash boiling spray of dimethyl ether  

NASA Astrophysics Data System (ADS)

The high-speed digital imaging technique is applied to observe the developing process of flash boiling spray of dimethyl ether at low ambient pressure, and the effects of nozzle opening pressure and nozzle hole diameter on the spray shape, spray tip penetration and spray angle during the injection are investigated. The experimental results show that the time when the vortex ring structure of flash boiling spray forms and its developing process are determined by the combined action of the bubble growth and breakup in the spray and the air drag on the leading end of spray; with the enhancement of nozzle opening pressure, the spray tip penetration increases and the spray angle decreases. The influence of nozzle hole diameter on the spray tip penetration is relatively complicated, the spray tip penetration is longer with a smaller nozzle hole diameter at the early stage of injection, while the situation is just opposite at the later stage of injection. This paper establishes that the variation of spray angle is consistent with that of nozzle hole diameter.

Zhang, Peng

2014-12-01

42

Microwave spectrum of two top molecules in the excited states dimethyl ether, dimethyl sulfide, and dimethyl silane  

NASA Astrophysics Data System (ADS)

Microwave spectra of dimethyl ether, dimethyl sulfide, and dimethyl silane in the torsionally excited states have been measured. The methyl internal rotations of these molecules were analyzed from the observed multiplets and from the reported multiplets of transitions. The method developed for ethyl silane in the previous paper was extended to equivalent two top molecules. For equivalent two top molecules, apparent barriers of methyl internal rotations obtained from the experiments were corrected by the kinetic and potential cross terms. They are V3=2645.8±10.0, 2632.4 ± 42.9, 2146.0 ± 13.8, 1651.5 ± 10.1, 1648.0 ± 13.7, and 1649.9 ± 11.8 cal/mol for (CH 3) 2O, (CD 3) 2O, (CH 3) 2S, (CH 3) 2SiH 2, (CH 3) 2SiD 2, and (CH 3) 2SiHD, respectively. The potential cross terms, V12(1-cos3 ?1)(1-cos3 ?2) terms are negligible for the three molecules, while V'12sin3 ?1sin3 ?2 terms are also very close to zero except those for (CH 3) 2O and (CD 3) 2O which are small but not negligible ( V'12=-124.4,-158.0 cal/mol). The investigations were extended to those of non-equivalent two top species and the corrected barriers of the methyl tops, V3, are obtained to be 2615.6 ± 8.6 and 2155.0 ± 15.2 cal/mol for CH 3OCD 3 and CH 3SCD 3. The corrected barrier, V3(CD 3) of CH 3OCD 3, is obtained to be 2634.4 ± 7.1 cal/mol, while that of CH 3SCD 3 cannot be solved due to the lack of the data available.

Niide, Yuzuru; Hayashi, Michiro

2004-02-01

43

Steam reforming of dimethyl ether for generating hydrogen-rich fuel-cell feeds  

NASA Astrophysics Data System (ADS)

This research evaluates both the thermodynamic and experimental aspects of dimethyl ether as a hydrogen carrier for fuel-cell feeds. The thermodynamics of generating hydrogen from dimethyl ether via partial oxidation, by steam reforming, or by the combined processes of partial oxidation and steam reforming were investigated as functions of temperature (100°C--600°C), steam-to-carbon ratio (0.00--4.00), oxygen-to-carbon ratio (0.00--2.80), pressure (1--5 atm) and product species. Thermodynamically, the resulting optimal processing conditions for dimethyl ether steam reforming occurred at a steam-to-carbon ratio of 1.50, a pressure of 1 atm and a temperature of 200°C, resulting in a hydrogen production efficiency of 97%. These results also showed that dimethyl ether hydrolysis to methanol, the first step in the steam reforming process to form hydrogen, was equilibrium limited. Modeling the start-up energies and efficiencies of an automotive scale on-board fuel processor was also carried out as a function of fuel source (methane, methanol, ethanol, dimethyl ether and gasoline). Results demonstrated that a fuel processor utilizing dimethyl ether yielded the highest overall efficiency. Dimethyl ether hydrolysis to form methanol (the desired intermediate) was studied experimentally over a series of as-received catalysts of varying acidity (zeolites Y and ZSM-5, ZrO2, gamma-Al2O 3, SiO2 and BASF K3-110) and also a series of in-house prepared composite catalysts containing copper and zinc, using a packed-bed reactor. All the acid catalysts, with the exception of ZrO2, attained the previously calculated equilibrium-limited conversions to methanol in the temperature range of interest (125°C--400°C). Several homogeneous physical mixtures containing both an as-received acid catalyst and BASF K3-110 (a methanol-to-hydrogen catalyst) were used to examine the process of converting dimethyl ether to hydrogen, (i.e., dimethyl ether steam reforming). Hydrogen production efficiencies exceeding 95% and hydrogen production rates exceeding 85 mmoles gcat -1 h-1 were observed. In-house prepared composite catalysts, consisting of copper and zinc loaded onto a solid-acid substrate via incipient wetness or co-ion exchange, were also evaluated for dimethyl ether steam reforming activity, but were generally found less active than the physical mixture catalysts. Variations in catalyst activity and selectivity are discussed in terms of zeolite characteristics. In situ DRIFTS experiments were also performed.

Semelsberger, Troy Allen

44

Chemical recycling of carbon dioxide to methanol and dimethyl ether: from greenhouse gas to renewable, environmentally carbon neutral fuels and synthetic hydrocarbons.  

PubMed

Nature's photosynthesis uses the sun's energy with chlorophyll in plants as a catalyst to recycle carbon dioxide and water into new plant life. Only given sufficient geological time can new fossil fuels be formed naturally. In contrast, chemical recycling of carbon dioxide from natural and industrial sources as well as varied human activities or even from the air itself to methanol or dimethyl ether (DME) and their varied products can be achieved via its capture and subsequent reductive hydrogenative conversion. The present Perspective reviews this new approach and our research in the field over the last 15 years. Carbon recycling represents a significant aspect of our proposed Methanol Economy. Any available energy source (alternative energies such as solar, wind, geothermal, and atomic energy) can be used for the production of needed hydrogen and chemical conversion of CO(2). Improved new methods for the efficient reductive conversion of CO(2) to methanol and/or DME that we have developed include bireforming with methane and ways of catalytic or electrochemical conversions. Liquid methanol is preferable to highly volatile and potentially explosive hydrogen for energy storage and transportation. Together with the derived DME, they are excellent transportation fuels for internal combustion engines (ICE) and fuel cells as well as convenient starting materials for synthetic hydrocarbons and their varied products. Carbon dioxide thus can be chemically transformed from a detrimental greenhouse gas causing global warming into a valuable, renewable and inexhaustible carbon source of the future allowing environmentally neutral use of carbon fuels and derived hydrocarbon products. PMID:19063591

Olah, George A; Goeppert, Alain; Prakash, G K Surya

2009-01-16

45

Performance evaluation of chemically recuperated gas turbine (CRGT) power plants fuelled by di-methyl-ether (DME)  

Microsoft Academic Search

This paper reports a performance analysis on CRGT power plants fuelled by DME, which is a potentially attractive fuel for gas turbines. The study also includes a performance comparison of simple cycle gas turbines fuelled by natural gas, DME and methanol. The study shows that, owing to the exhaust heat recovery carried out through DME pre-heating and vaporization before combustion,

Daniele Cocco; Vittorio Tola; Giorgio Cau

2006-01-01

46

Insight into selected reactions in low-temperature dimethyl ether combustion from Born-Oppenheimer molecular dynamics.  

PubMed

Dimethyl ether is under consideration as an alternative diesel fuel. Its combustion chemistry is as yet ill-characterized. Here we use Born-Oppenheimer molecular dynamics (BOMD) based on DFT-B3LYP forces to investigate the short-time dynamics of selected features of the low-temperature dimethyl ether (DME) oxidation potential energy surface. Along the chain propagation pathway, we run BOMD simulations from the transition state involving the decomposition of (*)CH(2)OCH(2)OOH to two CH(2)=O and an (*)OH radical. We predict that formaldehyde C-O stretch overtones are excited, consistent with laser photolysis experiments. We also predict that O-H overtones are excited for the (*)OH formed from (*)CH(2)OCH(2)OOH dissociation. We also investigate short-time dynamics involved in chain branching. First, we examine the isomerization transition state of (*)OOCH(2)OCH(2)OOH --> HOOCH(2)OCHOOH. The latter species is predicted to be a short-lived metastable radical that decomposes within 500 fs to hydroperoxymethyl formate (HPMF; HOOCH(2)OC(=O)H) and the first (*)OH of chain branching. The dissociation of HOOCH(2)OCHOOH exhibits non-RRKM behavior in its lifetime profile, which may be due to conformational constraints or slow intramolecular vibrational energy transfer (IVR) from the nascent H-O bond to the opposite end of the radical, where O-O scission occurs to form HPMF and (*)OH. In a few trajectories, we see HOOCH(2)OCHOOH recross back to (*)OOCH(2)OCH(2)OOH because the isomerization is endothermic, with only an 8 kcal/mol barrier to recrossing. Therefore, some inhibition of chain-branching may be due to recrossing. Second, trajectories run from the transition state leading to the direct decomposition of HPMF (an important source of the second (*)OH radical in chain branching) to HCO, (*)OH, and HC(=O)OH show that these products can recombine to form many other possible products. These products include CH(2)OO + HC(=O)OH, H(2)O + CO + HC(=O)OH, HC(=O)OH + HC(=O)OH, and HC(=O)C(=O)H + H(2)O, which (save CH(2)OO + HC(=O)OH) are all more thermodynamically stable than the original HCO + (*)OH + HC(=O)OH products. Moreover, the multitude of extra products suggest that standard statistical rate theories cannot completely describe the reaction kinetics of significantly oxygenated compounds such as HPMF. These secondary products consume the second (*)OH required for explosive combustion, suggesting an inhibition of DME fuel combustion is likely. PMID:16435800

Andersen, Amity; Carter, Emily A

2006-02-01

47

A novel DME steam-reforming catalyst designed with fact database on-demand  

NASA Astrophysics Data System (ADS)

Novel catalysts for dimethyl ether (DME) steam reforming (SR) were designed based on catalysis database on-demand. A catalyst library consisting of precious metals loaded on various metal oxides was tested for DME SR and its elemental reactions of DME hydrolysis and MeOH SR. Platinum loaded on alumina, Pt/Al 2O 3, shows high activity for DME SR as reported previously. The drawback of the catalyst was also confirmed; the formation of methane leading to the reduction of hydrogen formation. From the fact database for DME hydrolysis and MeOH SR built up with high-throughput experimentation tools, the high activity of Pt/Al 2O 3 for DME SR is owing to its high activity on DME hydrolysis because its activity on MeOH steam reforming is not remarkable. Based on these facts, novel catalysts were designed and achieved by physical mixing of Pt/Al 2O 3 which reveals high activity on DME hydrolysis with an active catalyst on MeOH steam reforming. By mixing of Pt/Al 2O 3 with Pd/Al 2O 3, methane formation was suppressed without loss of hydrogen production activity.

Yamada, Yusuke; Mathew, Thomas; Ueda, Atsushi; Shioyama, Hiroshi; Kobayashi, Tetsuhiko

2006-01-01

48

IMPACT OF DME-DIESEL FUEL BLEND PROPERTIES ON DIESEL FUEL INJECTION SYSTEMS  

SciTech Connect

The objectives of this research program are to develop information on lubricity and viscosity improvers and their impact on the wear mechanisms in fuel injectors operating on blends of dimethyl ether (DME) and diesel fuel. Since DME is a fuel with no lubricity (i.e., it does not possess the lubricating quality of diesel fuel), conventional fuel delivery and fuel injection systems are not compatible with dimethyl ether. Therefore, to operate a diesel engine on DME one must develop a fuel-tolerant injection system, or find a way to provide the necessary lubricity to the DME. In the shuttle bus project, we have chosen the latter strategy in order to achieve the objective with minimal need to modify the engine. Our strategy is to blend DME with diesel fuel, to obtain the necessary lubricity to protect the fuel injection system and to achieve low emissions. In this project, we have sought to develop methods for extending the permissible DME content in the DME-diesel blends without experiencing rapid injector failure due to wear. To date, our activities have covered three areas: examination of the impact of lubricity additives on the viscosity of DME, development of a high-pressure lubricity test apparatus for studies of lubricity and viscosity improvers and development of an injector durability stand for evaluation of wear rates in fuel injectors. This report provides summaries of the progress toward evaluation of the viscosity impacts of lubricity additives, completion of both experimental systems and a summary of the plan for completion of the project objectives.

Elana M. Chapman; Andre Boehman; Kimberly Wain; Wallis Lloyd; Joseph M. Perez; Donald Stiver; Joseph Conway

2003-06-01

49

Study on diesel-DME spray using open-source CFD (OpenFoam)  

NASA Astrophysics Data System (ADS)

In this work, a numerical study has been performed to evaluate the fuel spray of diesel, dimethyl ether (DME) and its mixture using CFD code OpenFoam. This study uses a general method, based on simulating fuel sprays injected into a constant volume vessel. Calculations results are presented as profiles of diameter (MD) and temperature of fuel droplets as function of fuel type. The results have shown that the diameter of fuel droplet decreased as the fraction of DME in the mixture is higher. Fuel properties affected the atomization and evaporation process. The SMD increased with viscosity and the evaporation rate of fuel spray increased with fuel volatility.

Fajar, Rizqon; Sugiarto, Bambang; Darsono, Dody

2012-06-01

50

IMPACT OF DME-DIESEL FUEL BLEND PROPERTIES ON DIESEL FUEL INJECTION SYSTEMS  

SciTech Connect

The objectives of this research program are to develop information on lubricity and viscosity improvers and their impact on the wear mechanisms in fuel injectors operating on blends of dimethyl ether (DME) and diesel fuel. Since DME is a fuel with no lubricity (i.e., it does not possess the lubricating quality of diesel fuel), conventional fuel delivery and fuel injection systems are not compatible with dimethyl ether. Therefore, to operate a diesel engine on DME one must develop a fuel-tolerant injection system, or find a way to provide the necessary lubricity to the DME. In the shuttle bus project, we have chosen the latter strategy in order to achieve the objective with minimal need to modify the engine. Our strategy is to blend DME with diesel fuel, to obtain the necessary lubricity to protect the fuel injection system and to achieve low emissions. In this project, we have sought to develop methods for extending the permissible DME content in the DME-diesel blends without experiencing rapid injector failure due to wear. Our activities have covered three areas: examination of the impact of lubricity additives on the viscosity of DME, development of a high-pressure lubricity test apparatus for studies of lubricity and viscosity improvers and development of an injector durability stand for evaluation of wear rates in fuel injectors. The first two of these areas have resulted in valuable information about the limitations of lubricity and viscosity additives that are presently available in terms of their impact on the viscosity of DME and on wear rates on injector hardware. The third area, that of development of an injector durability test stand, has not resulted in a functioning experiment. Some information is provided in this report to identify the remaining tasks that need to be performed to make the injector stand operational. The key observations from the work are that when blended at 25 wt.% in either diesel fuel or Biodiesel fuel, DME requires more than 5 wt.% additive of all viscosity and lubricity additives tested here to even approach the lower limit of the ASTM diesel fuel viscosity requirement. To treat neat DME sufficiently to make DME comply with the ASTM diesel fuel viscosity requirement would require a viscosity additive with 10{sup 45} cSt viscosity, which is not possible with current additive technologies.

Elana M. Chapman; Andre Boehman; Kimberly Wain; Wallis Lloyd; Joseph M. Perez; Donald Stiver; Joseph Conway

2004-04-01

51

CFD MODELING OF DIESEL OIL AND DME PERFORMANCE IN A TWO-STROKE FREE PISTON ENGINE  

Microsoft Academic Search

This paper presents the CFD KIVA3V, rel. 2 model and numerical results of combustion process simulations in a two-stroke, uniflow scavenging dual free piston engine, FPE, designed for electricity generation. Two fuels, diesel oil and dimethyl ether (DME), were studied in order to achieve HCCI-like combustion. Limited size reaction mechanisms were constructed and used in the modeling. The diesel oil

V. I. GOLOVITCHEV; M. BERGMAN; L. MONTORSI

2007-01-01

52

Reinvestigation of microwave spectrum of dimethyl ether and rs structures of analogous molecules  

NASA Astrophysics Data System (ADS)

Microwave spectra of dimethyl ether and its sixteen isotopic species have been measured. For species with singlet spectra, a least-squares analysis of observed transition frequencies gave rotational and five quartic centrifugal distortion constants. For species with multiplet spectra due to the methyl internal rotation, a least-squares analysis of observed multiplet frequencies gave not only unperturbed rotational and five quartic centrifugal distortion constants but also the quantities related to the methyl internal rotation. The rs structures from (CH 3) 2O, CH 3OCD 3, and (CD 3) 2O species as the parent species, respectively, were compared with one another. The proposed rs structure has been established from all the species measured and was compared with the rs-like structure obtained by a diagnostic least-squares method and with the reported structure. The rs structure of the present molecule was compared with the reported structures of dimethyl sulfide and dimethyl silane in relation to the tilt phenomenon. The rs structure of dimethyl sulfide was revised based on the present comparison.

Niide, Yuzuru; Hayashi, Michiro

2003-07-01

53

Liquid densities, kinematic viscosities, and heat capacities of some ethylene glycol dimethyl ethers at temperatures from 283.15 to 423.15 K  

SciTech Connect

Liquid densities and heat capacities at 1 MPa, and kinematic viscosities at atmospheric pressure of monoethylene glycol dimethyl ether (MEGDME), diethylene glycol dimethyl ether (DEGDME), triethylene glycol dimethyl ether (TrEGDME), tetrathylene glycol dimethyl ether (TEGDME), pentaethylene glycol dimethyl ether (PeEGDME), and polyethylene glycol 250 dimethyl ether (PEGDMe 250) were measured in the temperature range from 283.15 to 423.15 K. For each substance, experimental data were correlated with temperature using empirical polynomial equations. The experimental data were also used to evaluate the predictive capability of some estimation methods of liquid densities and heat capacities for the studied ethylene glycol dimethyl ethers. The densities estimated by the Yen-Woods equation agree with the experimental values with a root-mean-square relative deviation (RMSD) of 3.21% for all ethylene glycol dimethyl ethers. The best estimated results of liquid heat capacities were obtained from the Rowlinson equation based on the corresponding-states principle, with a RMSD of 1.12%. The group-contribution methods give the worst results, especially at high temperatures.

Conesa, A.; Coronas, A. [Univ. Rovira i Virgili, Tarragona (Spain). Dept. of Mechanical Engineering] [Univ. Rovira i Virgili, Tarragona (Spain). Dept. of Mechanical Engineering; Shen, S. [Nanjing Univ. of Chemical Technology (China)] [Nanjing Univ. of Chemical Technology (China)

1998-09-01

54

Lifetimes and global warming potentials for dimethyl ether and for fluorinated ethers: CH 3 OCF 3 (E143a), CHF 2 OCHF 2 (E134), CHF 2 OCF 3 (E125)  

Microsoft Academic Search

Using recent kinetic data, two-dimensional (2-D) chemical-transport modeling of the atmospheric lifetimes of dimethyl ether and fluorinated ethers CH3OCF 3 (E143a), CHF2OCHF 2 (E134), and CHF2OCF3 (E125) shows that E134 and E125 have substantially larger lifetimes than previously estimated. Dimethyl ether has a short atmospheric lifetime of 5.1 days and a relatively insignificant radiative forcing leading to a relatively low

D. A. Good; J. S. Francisco; A. K. Jain; D. J. Wuebbles

1998-01-01

55

Lifetimes and global warming potentials for dimethyl ether and for fluorinated ethers: CH3OCF3 (E143a), CHF2OCHF2 (El34), CHF2OCF3 (E125)  

Microsoft Academic Search

Using recent kinetic data, two-dimensional (2-D) chemical-transport modeling of the atmospheric lifetimes of dimethyl ether and fluorinated ethers CH3OCF3 (E143a), CHF2OCHF2 (E134), and CHF2OCF3 (E125) shows that E134 and E125 have substantially larger lifetimes than previously estimated. Dimethyl ether has a short atmospheric lifetime of 5.1 days and a relatively insignificant radiative forcing leading to a relatively low global warming

D. A. Good; J. S. Francisco; A. K. Jain; D. J. Wuebbles

1998-01-01

56

Commercial-scale demonstration of the Liquid Phase Methanol (LPMEOH{trademark}) Process. Peroxide formation of dimethyl ether in methanol mixtures  

SciTech Connect

Organic peroxides could form when dimethyl ether in methanol is stored for three to six months at a time. The objective of this work was to determine the level of peroxide formation from dimethyl ether in reagent grade methanol and raw methanol at room temperature under 3 atmospheres (45 psig) of air. Raw methanol is methanol made from syngas by the LPMEOH Process without distillation. Aliphatic ethers tend to react slowly with oxygen from the air to form unstable peroxides. However, there are no reports on peroxide formation from dimethyl ether. After 172 days of testing, dimethyl ether in either reagent methanol or raw methanol at room temperature and under 60--70 psig pressure of air does not form detectable peroxides. Lack of detectable peroxides suggests that dimethyl ether or dimethyl ether and methanol may be stored at ambient conditions. Since the compositions of {approximately} 1.3 mol% or {approximately} 4.5 mol% dimethyl ether in methanol do not form peroxides, these compositions can be considered for diesel fuel or an atmospheric turbine fuel, respectively.

Waller, F.J.

1997-11-01

57

Process for the production of ethylidene diacetate from dimethyl ether using a heterogeneous catalyst  

DOEpatents

This invention relates to a process for producing ethylidene diacetate by the reaction of dimethyl ether, acetic acid, hydrogen and carbon monoxide at elevated temperatures and pressures in the presence of an alkyl halide and a heterogeneous, bifunctional catalyst that is stable to hydrogenation and comprises an insoluble polymer having pendant quaternized heteroatoms, some of which heteroatoms are ionically bonded to anionic Group VIII metal complexes, the remainder of the heteroatoms being bonded to iodide. In contrast to prior art processes, no accelerator (promoter) is necessary to achieve the catalytic reaction and the products are easily separated from the catalyst by filtration. The catalyst can be recycled for 3 consecutive runs without loss in activity.

Ramprasad, D.; Waller, F.J.

1998-04-28

58

Process for the production of ethylidene diacetate from dimethyl ether using a heterogeneous catalyst  

DOEpatents

This invention relates to a process for producing ethylidene diacetate by the reaction of dimethyl ether, acetic acid, hydrogen and carbon monoxide at elevated temperatures and pressures in the presence of an alkyl halide and a heterogeneous, bifunctional catalyst that is stable to hydrogenation and comprises an insoluble polymer having pendant quaternized heteroatoms, some of which heteroatoms are ionically bonded to anionic Group VIII metal complexes, the remainder of the heteroatoms being bonded to iodide. In contrast to prior art processes, no accelerator (promoter) is necessary to achieve the catalytic reaction and the products are easily separated from the catalyst by filtration. The catalyst can be recycled for 3 consecutive runs without loss in activity.

Ramprasad, Dorai (Allentown, PA); Waller, Francis Joseph (Allentown, PA)

1998-01-01

59

Wettability, optical properties and molecular structure of plasma polymerized diethylene glycol dimethyl ether  

NASA Astrophysics Data System (ADS)

Modern industry has frequently employed ethylene glycol ethers as monomers in plasma polymerization process to produce different types of coatings. In this work we used a stainless steel plasma reactor to grow thin polymeric films from low pressure RF excited plasma of diethylene glycol dimethyl ether. Plasmas were generated at 5W RF power in the range of 16 Pa to 60 Pa. The molecular structure of plasma polymerized films and their optical properties were analyzed by Fourier Transform Infrared Spectroscopy (FTIR) and Ultraviolet-Visible Spectroscopy, respectively. The IR spectra show C-H stretching at 3000-2900 cm-1, C=O stretching at 1730-1650 cm-1, C-H bending at 1440-1380 cm-1, C-O and C-O-C stretching at 1200-1000 cm-1. The refraction index was around 1.5 and the optical gap calculated from absorption coefficient presented value near 3.8 eV. Water contact angle of the films ranged from 40° to 35° with corresponding surface energy from 66 to 73×10-7 J. Because of its favorable optical and hydrophilic characteristics these films can be used in ophthalmic industries as glass lenses coatings.

Azevedo, T. C. A. M.; Algatti, M. A.; Mota, R. P.; Y Honda, R.; Kayama, M. E.; Kostov, K. G.; Fernandes, R. S.; Cruz, N. C.; Rangel, E. C.

2009-05-01

60

STUDIES ON THE LIFTOFF PROPERTIES OF DIMETHYL ETHER JET DIFFUSION FLAMES  

Microsoft Academic Search

The liftoff properties of the DME jet diffusion flame were investigated experimentally and analytically with Emphasis on the influences of flame stretch and fuel oxygen. The present experiments showed that the DME jet diffusion flame exhibited a distinct liftoff phenomenon that differed from other hydrocarbon fuels. This unique phenomenon was analyzed theoretically by taking into consideration the effects of flame

YUAN XUE; YIGUANG JU

2006-01-01

61

Process Design, Simulation and Integration of Dimethyl Ether (DME) Production from Shale Gas by Direct and Indirect Methods  

E-print Network

of sustainable energy. Over the last decade, the U.S has witnessed substantial growth in shale gas production. Consequently, shale gas has become a competitive feedstock for usage as energy and production of chemicals and petrochemicals. A valuable product which...

Karagoz, Secgin

2014-08-11

62

Bio-refinery system of DME or CH4 production from black liquor gasification in pulp mills.  

PubMed

There is great interest in developing black liquor gasification technology over recent years for efficient recovery of bio-based residues in chemical pulp mills. Two potential technologies of producing dimethyl ether (DME) and methane (CH(4)) as alternative fuels from black liquor gasification integrated with the pulp mill have been studied and compared in this paper. System performance is evaluated based on: (i) comparison with the reference pulp mill, (ii) fuel to product efficiency (FTPE) and (iii) biofuel production potential (BPP). The comparison with the reference mill shows that black liquor to biofuel route will add a highly significant new revenue stream to the pulp industry. The results indicate a large potential of DME and CH(4) production globally in terms of black liquor availability. BPP and FTPE of CH(4) production is higher than DME due to more optimized integration with the pulping process and elimination of evaporation unit in the pulp mill. PMID:19767203

Naqvi, M; Yan, J; Fröling, M

2010-02-01

63

Development of an Optical Gas Leak Sensor for Detecting Ethylene, Dimethyl Ether and Methane  

PubMed Central

In this paper, we present an approach to develop an optical gas leak sensor that can be used to measure ethylene, dimethyl ether, and methane. The sensor is designed based on the principles of IR absorption spectrum detection, and comprises two crossed elliptical surfaces with a folded reflection-type optical path. We first analyze the optical path and the use of this structure to design a miniature gas sensor. The proposed sensor includes two detectors (one to acquire the reference signal and the other for the response signal), the light source, and the filter, all of which are integrated in a miniature gold-plated chamber. We also designed a signal detection device to extract the sensor signal and a microprocessor to calculate and control the entire process. The produced sensor prototype had an accuracy of ±0.05%. Experiments which simulate the transportation of hazardous chemicals demonstrated that the developed sensor exhibited a good dynamic response and adequately met technical requirements. PMID:23539025

Tan, Qiulin; Pei, Xiangdong; Zhu, Simin; Sun, Dong; Liu, Jun; Xue, Chenyang; Liang, Ting; Zhang, Wendong; Xiong, Jijun

2013-01-01

64

Inhibition of monocyte adhesion and fibrinogen adsorption on glow discharge plasma deposited tetraethylene glycol dimethyl ether.  

PubMed

Monocytes and macrophages play important roles in host responses to implanted biomedical devices. Monocyte and macrophage interactions with biomaterial surfaces are thought to be mediated by adsorbed adhesive proteins such as fibrinogen and fibronectin. Non-fouling surfaces that minimize protein adsorption may therefore minimize monocyte adhesion, activation, and the foreign body response. Radio-frequency glow discharge plasma deposition (RF-GDPD) of tetraethylene glycol dimethyl ether (tetraglyme) was used to produce polyethylene oxide (PEO)-like coatings on a fluorinated ethylene-propylene (FEP) surface. Electron spectroscopy for chemical analysis (ESCA) and static time of flight secondary ion mass spectrometry (ToF-SIMS) were used to characterize the surface chemistry of tetraglyme coating. Fibrinogen adsorption to the tetraglyme surface was measured with 125I-labeled fibrinogen and ToF-SIMS. Adsorption of fibrinogen to plasma deposited tetraglyme was less than 10 ng cm(-2), a 20-fold decrease compared to untreated FEP or tissue culture polystyrene (TCPS). Monocyte adhesion to plasma deposited tetraglyme was significantly lower than adhesion to FEP or TCPS. In addition, when the surfaces were preadsorbed with fibrinogen, fibronectin, or blood plasma, monocyte adhesion to plasma deposited tetraglyme after 2 h or 1 day was much lower than adhesion to FEP. RF-GDPD tetraglyme coating provides a promising approach to make non-fouling biomaterials that can inhibit non-specific material-host interactions and reduce the foreign body response. PMID:11787523

Shen, M; Pan, Y V; Wagner, M S; Hauch, K D; Castner, D G; Ratner, B D; Horbett, T A

2001-01-01

65

Spectroscopy of a Major Complex Organic Molecule: Mono-Deuterated Dimethyl Ether  

NASA Astrophysics Data System (ADS)

Dimethyl ether is one of the most abundant molecule in star-forming regions. Like other complex organic molecules, its formation process is not yet clearly established. The study of deuteration may provide crucial hints. The mono-deuterated species (CH_2DOCH3) is still a relatively light molecule; its spectrum is the most intense in the THz domain even at ISM temperatures (100--150 K). Therefore, it is is necessary to measure and assign its transitions in this range in order to be able to compute accurate predictions which should allow us to detect it with ALMA, expected to be a powerful tool to observe such isotopic species. In this context, spectra between 50 and 950 GHz were recorded in Lille with a solid-state submillimeter-wave spectrometer. The starting point of the analysis was the centimeter-wave measurements carried out in 2003 for almost all isotopic species. Results concerning the symmetric conformer of the mono-deuterated species will be presented in the paper. The fits performed with the ERHAM code will be discussed. Theoretical development are in progress in order to treat the case of the asymmetric conformer. This work is supported by the CNES and the Action sur Projets de l'INSU, PCMI. This work is also funded by the ANR-08-BLAN-0054 and ANR-08-BLAN-0225 contracts. [1]Ceccarelli, Caselli, Herbst, et al., (eds.), University of Arizona Press, Tucson, 951 (2007) 47 [2]Niide et al., J. Mol.Spectrosc. 220 (2003) 65 [3]Groner, J. Chem. Phys. 107 (1997) 4483

Richard, C.; Margulès, L.; Motiyenko, R. A.; Groner, P.; Coudert, L. H.; Guillemin, J.-C.

2012-06-01

66

Structural Requirements and Reaction Pathways in Dimethyl Ether Combustion Catalyzed by Supported Pt Clusters  

E-print Network

by combining isotopic and kinetic analyses with density functional theory estimates of reaction energies to form two methoxides, consistent with measured rates and kinetic isotope effects. This kinetic of oxygen adatoms increases with coverage and they become more effective in hydrogen abstraction from DME

Iglesia, Enrique

67

Computational and experimental study of the effects of adding dimethyl ether and ethanol to nonpremixed ethylene/air flames  

SciTech Connect

Two sets of axisymmetric laminar coflow flames, each consisting of ethylene/air nonpremixed flames with various amounts (up to 10%) of either dimethyl ether (CH{sub 3}-O-CH{sub 3}) or ethanol (CH{sub 3}-CH{sub 2}-OH) added to the fuel stream, have been examined both computationally and experimentally. Computationally, the local rectangular refinement method, which incorporates Newton's method, is used to solve the fully coupled nonlinear conservation equations on solution-adaptive grids for each flame in two spatial dimensions. The numerical model includes C6 chemical kinetic mechanisms with up to 59 species, detailed transport, and an optically thin radiation submodel. Experimentally, thermocouples are used to measure gas temperatures, and mass spectrometry is used to determine concentrations of over 35 species along the flame centerline. Computational results are examined throughout each flame, and validation of the model occurs through comparison with centerline measurements. Very good agreement is observed for temperature, major species, and several minor species. As the level of additive is increased, temperatures, some major species (CO{sub 2}, C{sub 2}H{sub 2}), flame lengths, and residence times are essentially unchanged. However, peak centerline concentrations of benzene (C{sub 6}H{sub 6}) increase, and this increase is largest when dimethyl ether is the additive. Computational and experimental results support the hypothesis that the dominant pathway to C{sub 6}H{sub 6} formation begins with the oxygenates decomposing into methyl radical (CH{sub 3}), which combines with C2 species to form propargyl (C{sub 3}H{sub 3}), which reacts with itself to form C{sub 6}H{sub 6}. (author)

Bennett, Beth Anne V.; McEnally, Charles S.; Pfefferle, Lisa D.; Smooke, Mitchell D. [Center for Combustion Studies, Yale University, New Haven, CT 06511 (United States); Colket, Meredith B. [United Technologies Research Center, East Hartford, CT 06108 (United States)

2009-06-15

68

Synthesis of dimethyl ether and alternative fuels in the liquid phase from coal-derived synthesis gas  

SciTech Connect

As part of the DOE-sponsored contract Synthesis of Dimethyl Ether and Alternative Fuels in the Liquid Phase from Coal-Derived Syngas'' experimental evaluations of the one-step synthesis of alternative fuels were carried out. The objective of this work was to develop novel processes for converting coal-derived syngas to fuels or fuel additives. Building on a technology base acquired during the development of the Liquid Phase Methanol (LPMEOH) process, this work focused on the development of slurry reactor based processes. The experimental investigations, which involved bench-scale reactor studies, focused primarily on three areas: (1) One-step, slurry-phase syngas conversion to hydrocarbons or methanol/hydrocarbon mixtures using a mixture of methanol synthesis catalyst and methanol conversion catalyst in the same slurry reactor. (2) Slurry-phase conversion of syngas to mixed alcohols using various catalysts. (3) One-step, slurry-phase syngas conversion to mixed ethers using a mixture of mixed alcohols synthesis catalyst and dehydration catalyst in the same slurry reactor. The experimental results indicate that, of the three types of processes investigated, slurry phase conversion of syngas to mixed alcohols shows the most promise for further process development. Evaluations of various mixed alcohols catalysts show that a cesium-promoted Cu/ZnO/Al[sub 2]O[sub 3] methanol synthesis catalyst, developed in Air Products' laboratories, has the highest performance in terms of rate and selectivity for C[sub 2+]-alcohols. In fact, once-through conversion at industrially practical reaction conditions yielded a mixed alcohols product potentially suitable for direct gasoline blending. Moreover, an additional attractive aspect of this catalyst is its high selectivity for branched alcohols, potential precursors to iso-olefins for use in etherification.

Underwood, R.P.

1993-01-01

69

HIGH-RESOLUTION EXPANDED VERY LARGE ARRAY IMAGE OF DIMETHYL ETHER (CH{sub 3}){sub 2}O IN ORION-KL  

SciTech Connect

We report the first subarcsecond (0.''65 x 0.''51) image of the dimethyl ether molecule, (CH{sub 3}){sub 2}O, toward the Orion Kleinmann-Low nebula. The observations were carried at 43.4 GHz with the Expanded Very Large Array (EVLA). The distribution of the lower energy transition 6{sub 1,5}-6{sub 0,6}, EE (E {sub u} = 21 K) mapped in this study is in excellent agreement with the published dimethyl ether emission maps imaged with a lower resolution. The main emission peaks are observed toward the Compact Ridge and Hot Core southwest components, at the northern parts of the Compact Ridge and in an intermediate position between the Compact Ridge and the Hot Core. A notable result is that the distribution of dimethyl ether is very similar to that of another important larger O-bearing species, the methyl formate (HCOOCH{sub 3}), imaged at a lower resolution. Our study shows that higher spectral resolution (WIDAR correlator) and increased spectral coverage provided by the EVLA offer new possibilities for imaging complex molecular species. The sensitivity improvement and the other EVLA improvements make this instrument well suited for high sensitivity, high angular resolution, and molecular line imaging.

Favre, C. [Department of Physics and Astronomy, University of Arhus, Ny Munkegade 120, DK-8000 Arhus C (Denmark); Wootten, H. A.; Remijan, A. J. [National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903-2475 (United States); Brouillet, N.; Despois, D.; Baudry, A. [Universite de Bordeaux, OASU, 2 rue de l'Observatoire, BP 89, 33271 Floirac Cedex (France); Wilson, T. L., E-mail: favre@phys.au.dk, E-mail: brouillet@obs.u-bordeaux1.fr, E-mail: despois@obs.u-bordeaux1.fr, E-mail: baudry@obs.u-bordeaux1.fr, E-mail: awootten@nrao.edu, E-mail: aremijan@nrao.edu, E-mail: tom.wilson@nrl.navy.mil [Naval Research Laboratory, Code 7210, Washington, DC 20375 (United States)

2011-09-20

70

Electrochemical Investigation of Li-Al Anodes in Oligo (ethylene glycol) Dimethyl ether/LiPF6  

SciTech Connect

LiPF{sub 6} dissolved in oligo(ethylene glycol) dimethyl ether with a molecular weight 5 g mol{sup -1} was investigated as a new electrolyte (OEGDME5, 1 M LiPF{sub 6}) for metal deposition and battery applications. At 25 C a conductivity of .48 x 1{sup -3} S cm{sup -1} was obtained and at 85 C, 3.78 x 1{sup -3} S cm{sup -1}. The apparent activation barrier for ionic transport was evaluated to be 3.7 kJ mol{sup -1}. OEGDME5, 1 M LiPF{sub 6} allows operating temperature above 1 C with very attractive conductivity. The electrolyte shows excellent performance at negative and positive potentials. With this investigation, we report experimental results obtained with aluminum electrodes using this electrolyte. At low current densities lithium ion reduction and re-oxidation can be achieved on aluminum electrodes at potentials about 28 mV more positive than on lithium electrodes. In situ X-ray diffraction measurements collected during electrochemical lithium deposition on aluminum electrodes show that the shift to positive potentials is due to the negative Gibbs free energy change of the Li-Al alloy formation reaction.

Y Zhou; X Wang; H Lee; K Nam; X Yang; O Haas

2011-12-31

71

Calculations for the properties and reactions of the NH, PH, and AsH counterparts of dimethyl ether and acetone.  

PubMed

The properties and reactions of compounds in which the O of dimethyl ether or acetone has been replaced by NH, PH, or AsH have been studied computationally using CBS-QB3, CBS-APNO, G4, and W1BD. The properties include the bond dissociation energies and ionization potentials, and the reactions include those with with protons, methyl cations, and lithium cations. The effect on keto-enol equilibria also was examined. In all cases there was good agreement with the available experimental data. The agreement between these methods suggests that the least computationally costly model (CBS-QB3) should be of general use in studying organic compounds. The double-bond dissociation enthalpies of CH2?XHn were linearly related to those of the corresponding CH3-XHn+1 single bonds with a slope of 2.5. With the exception of C-C, the order corresponded to the electronegativity of X, suggesting that the differences are largely determined by internal Coulombic interactions. The differences in the electronegativities of the heteroatoms are largely responsible for the differences in the properties and reactions. Oxygen has a significantly higher electronegativity than the others, and as a result, the oxygen-substituted compounds are often different than the others. PMID:25358051

Wiberg, Kenneth B

2014-11-21

72

Optimized Structures and Proton Affinities of Fluorinated Dimethyl Ethers: An Ab Initio Study  

NASA Technical Reports Server (NTRS)

Ab initio methods have been used to investigate the proton affinity and the geometry changes upon protonation for the molecules (CH3)2O, (CH2F)2O, (CHF2)2O, and (CF3)2O. Geometry optimizations were performed at the MP2/3-2 I G level, and the resulting geometries were used for single-point energy MP2/6-31G calculations. The proton affinity calculated for (CH3)2O was 7 Kjoule/mole from the experimental value, within the desired variance of +/- 8Kjoule/mole for G2 theory, suggesting that the methodology used in this study is adequate for energy difference considerations. For (CF3)20, the calculated proton affinity of 602 Kjoule/mole suggests that perfluorinated ether molecules do not act as Lewis bases under normal circumstances; e.g. degradation of commercial lubricants in tribological applications.

Orgel, Victoria B.; Ball, David W.; Zehe, Michael J.

1996-01-01

73

Phase behavior of mixtures of polyoxyethylene(10) stearyl ether (Brij-76), 1-butanol, isooctane, and mixed polar solvents I. Water and formamide (or N,N-dimethyl formamide).  

PubMed

The isothermal phase diagram of the quaternary system polyoxyethylene(10) stearyl ether (Brij-76)/1-butanol/isooctane/water has been constructed at 30 degrees C with equal amounts of oil and water. A regular fishtail diagram was obtained, confirming the establishment of hydrophile-lipophile balance (HLB) in the system. Mixing of formamide (FA) [or N,N-dimethyl formamide (DMF)] with water as a cosolvent altered the HLB and decreased the solubilization capacity of the quaternary system. No three-phase body appeared at high FA or DMF content. Similar observations were noted for temperature-induced phase diagrams. The effect of DMF was more pronounced than that of FA in reducing the maximum solubilization capacity. The results have been summarized on the basis of HLB and mutual solubility of the components. PMID:16643941

Nandy, Debdurlav; Mitra, Rajib K; Paul, Bidyut K

2006-08-01

74

Laboratory rotational spectrum of singly 13C-substituted dimethyl ether up to 1.5 THz and interstellar detection of 13CH_3O12CH_3 - a fruitful interplay between laboratory work and inter  

NASA Astrophysics Data System (ADS)

Dimethyl ether (CH_3OCH_3) is found in high abundance in star forming regions. However, the interstellar formation process of dimethyl ether still remains unclear up to now. In current gas-grain models gas-phase synthesis via self-methylation of methanol evaporating from grains is discussed in contrast to the surface reaction of CH_3 with successively hydrogenated CO (Garrod & Herbst 2006). An observational test for the formation mechanism has been proposed by Charnley et al. (2004) making use of the 13C fractionation into CO at low temperatures on grains: Comparing the 12C/13C ratio of molecules to the 12CO/13CO ratio allows to distinguish between formation from CO on cold grains and pure gas-phase formation routes. The isotopic ratio of species like dimethyl ether thus can be used as a tracer of the chemical evolution of the observed region. Due to its two methyl groups undergoing large amplitude motions and a relatively strong dipole moment of ? = 1.302 D it shows a strong and dense complex spectrum all over the terahertz region relevant for Herschel and ALMA observations. Accurate transition frequencies are needed to interpret the astronomical spectra. For the main isotopologue extensive data are now available (Endres et al. 2009). However, due to the greatly improved sensitivity of the new observatories isotopic species of abundant molecules like dimethyl ether are appearing in the spectra as well. In this work we present laboratory measurements of singly 13C-substituted dimethyl ether (13CH_3O12CH_3) up to 1.5 THz. More than 1700 transitions of 13CH_3O12CH_3 with rotational quantum numbers up to J = 53 and K = 25 have been analyzed. Based on the laboratory measurements singly 13C-substituted dimethyl ether has been detected for the first time in the spectrum of G327.3-0.6 (Bisschop et al. in prep.) and a preliminary value for the 12C/13C abundance ratio has been determined.

Koerber, M.; Bisschop, S.; Endres, C.; Lewen, F.; Schlemmer, S.

2011-05-01

75

A method for analysis of dimethyl selenide and dimethyl diselenide by LC-ICP-DRC-MS.  

PubMed

The aim of this work was to develop a simple and fast high performance liquid chromatography-inductively coupled argon plasma (ICP) mass spectrometry (MS) method capable of separating and detecting the two volatile selenium species dimethyl selenide (DMeSe) and dimethyl diselenide (DMeDSe) in biological samples. Dimethyl selenide and dimethyl diselenide were separated on a short reversed phase column using an eluent containing 40% methanol and detected by dynamic reaction cell ICP-MS monitoring the (80)Se isotope. The limit of detection was 8 nM for both species (corresponding to 0.6 and 1.3 ?g Se/L for DMeDSe and DMeSe, respectively). Both compounds exhibited a linear signal-concentration relationship in the investigated concentration range of 0.1-1 ?M with a precision on the determinations better than 3%. The method was applied for analysis of samples from cancer cell lines incubated with methylseleninic acid, selenomethionine, Se-methylselenocysteine, and sodium selenite. DMeDSe were detected in some samples. The method offers a simple and fast analysis of DMeDSe and DMeSe using standard liquid chromatography coupled with ICP-MS equipment and interfacing. PMID:20890781

Lunøe, Kristoffer; Skov, Søren; Gabel-Jensen, Charlotte; Stürup, Stefan; Gammelgaard, Bente

2010-12-01

76

Physicochemical and catalytic characteristics of La-H-ZSM-5 zeolite in converting dimethyl ether to the mixtures of gasoline hydrocarbons: Effect of ion exchange conditions  

NASA Astrophysics Data System (ADS)

The effect of the manner and conditions of introducing lanthanum cations into NH4-ZSM-5 zeolite on the properties of catalysts for the conversion of dimethyl ether into the mixtures of gasoline hydrocarbons is studied. The physicochemical properties of synthesized catalysts are studied by means of temperature-programmed ammonia desorption, the adsorption of benzene, atomic absorption spectroscopy, differential scanning calorimetry, and thermogravimetry. It is shown that the degree to which lanthanum cations are replaced by ammonium cations both depends on the conditions of ion exchange in the zeolite and affects its acidity spectrum and the selectivity of the formation of paraffin hydrocarbons with isostructure. It is concluded that an increase in the amount of introduced lanthanum leads to an increase in the content of iso-paraffins from 69 to 76 wt % and a decrease in the content of aromatic hydrocarbons from 10.5 to 5.5 wt % and that of durene from 1.5 to 0.2 wt % in the products.

Kitaev, L. E.; Bukina, Z. M.; Yushchenko, V. V.; Ionin, D. A.; Kolesnichenko, N. V.; Khadzhiev, S. N.

2014-03-01

77

C-O bond cleavage of dimethyl ether by transition metal ions: a systematic study on catalytic properties of metals and performance of DFT functionals.  

PubMed

Studies were focused on late 3d and 4d transition metal ion (Fe, Co, Ni, Cu, Ru, Rh, Pd, and Ag) mediated activation of dimethyl ether, to investigate the intrinsic catalytic properties of metals on C-O bond cleavage. A set of density functional (DFT) methods (BLYP, B3LYP, M06, M06-L, B97-1, B97-D, TPSS, and PBE0) with aug-cc-pVTZ were utilized, and the results were calibrated with CCSD(T)/CBS. The utility of CCSD(T)/CBS calculations for these systems was validated by MRCI/aug-cc-pVTZ calculations. Calculations showed an interesting energetic trend as a function of metal; earlier transition metals tend to give smaller reaction barriers and more exergonic reactions than later metals. This applies to both 3d and 4d systems. For the performance of DFT functionals, PBE0 gave the lowest root mean squared deviations (RMSDs) in terms of both reaction energies and barriers for both 3d and 4d systems, compared to the other functionals. Our studies found that the percentage of Hartree-Fock (HF) exchange plays an important role in the accuracy of DFT methods for these systems, and 26% HF exchange for 3d systems and 34% HF exchange for 4d systems gave the lowest RMSDs. PMID:23650902

Liu, Cong; Peterson, Charles; Wilson, Angela K

2013-06-20

78

Electrochemical Oxidation of Hydrolyzed Poly Oxymethylene-dimethyl Ether by PtRu Catalysts on Nb-Doped SnO2-? Supports for Direct Oxidation Fuel Cells.  

PubMed

We synthesized Pt and PtRu catalysts supported on Nb-doped SnO2-? (Pt/Sn0.99Nb0.01O2-?, PtRu/Sn0.99Nb0.01O2-?) for direct oxidation fuel cells (DOFCs) using poly oxymethylene-dimethyl ether (POMMn, n = 2, 3) as a fuel. The onset potential for the oxidation of simulated fuels of POMMn (methanol-formaldehyde mixtures; n = 2, 3) for Pt/Sn0.99Nb0.01O2-? and PtRu/Sn0.99Nb0.01O2-? was less than 0.3 V vs RHE, which was much lower than those of two commercial catalysts (PtRu black and Pt2Ru3/carbon black). In particular, the onset potential of the oxidation reaction of simulated fuels of POMMn (n = 2, 3) for PtRu/Sn0.99Nb0.01O2-? sintered at 800 °C in nitrogen atmosphere was less than 0.1 V vs RHE and is thus considered to be a promising anode catalyst for DOFCs. The mass activity (MA) of PtRu/Sn0.99Nb0.01O2-? sintered at 800 °C was more than five times larger than those of the commercial catalysts in the measurement temperature range from 25 to 80 °C. Even though the MA for the methanol oxidation reaction was of the same order as those of the commercial catalysts, the MA for the formaldehyde oxidation reaction was more than five times larger than those of the commercial catalysts. Sn from the Sn0.99Nb0.01O2-? support was found to have diffused into the Pt catalyst during the sintering process. The Sn on the top surface of the Pt catalyst accelerated the oxidation of carbon monoxide by a bifunctional mechanism, similar to that for Pt-Ru catalysts. PMID:25415540

Kakinuma, Katsuyoshi; Kim, In-Tae; Senoo, Yuichi; Yano, Hiroshi; Watanabe, Masahiro; Uchida, Makoto

2014-12-24

79

ORIGINAL ARTICLE DME/TACAN interference mitigation for GNSS: algorithms  

E-print Network

in this frequency band, in particular, pulsed signals from distance measuring equip- ment (DME) and tactical air, especially distance measuring equipment (DME) and tactical air navigation (TACAN) systems. DME provides- tion systems consist of an airborne interrogator and a ground-based transponder. DME and TACAN operate

Gao, Grace Xingxin

80

Theoretical study of the cooperativity in substituted dimethyl ethers complexed with two water molecules. Red or blue shifts of the ?(CH) vibrations?  

NASA Astrophysics Data System (ADS)

The cooperative interactions in CH3OCH3, CH3OCH2F, CH3OCHF2, CH2FOCHF2 and CHF2OCHF2 complexed with two H2O molecules are investigated using the B3LYP method with the 6-311++G(d,p) level. The calculations include the optimized geometries, the cooperative energies along with a natural bond orbital (NBO analysis). Cyclic complexes characterized by OwHw…O and CH…Ow hydrogen bonds are formed. The pairwise or two body interaction energies are computed. The results show that the OwHw…O interaction energies increase with the proton affinity of the O atom of the ethers and that the CH…Ow interaction energies increase with increasing acidity of the CH bond. This is in agreement with the intermolecular distances. The cooperative energy represents 15-20% of the total energy. When nF = 2-4, blue shifts are predicted for the ?(CH) vibration for the 1-1 complexes but red shifts are predicted for the 1-2 complexes. The variation of the CH distances is explained by a competition between the variation of the intramolecular hyperconjugation energies and the intermolecular hyperconjugation energies. The charge transfer between the ether and water molecules is analyzed. When the negative charge on one H2O molecule decreases, the positive charge on the other H2O molecule increases, indicating a nice reciprocal effect.

Chandra, Asit K.; Zeegers-Huyskens, Thérèse

2013-01-01

81

Preparation and catalytic performance of CuO-znO-AlO3/clinoptilolite nanocatalyst for single-step synthesis of dimethyl ether from syngas as a green fuel.  

PubMed

Direct conversion of syngas to dimethyl ether was successfully carried out over a clinoptilolite supported nanocatalyst modified by NH4Cl. A series of bifunctional nanocatalysts, CuO-ZnO-Al2O3 (CZA) over Clinoptilolite with different loading of CZA, were prepared via coprecipitation method and their catalytic performance were compared in a fixed-bed high pressure reactor. The catalysts were characterized by XRD, BET, FESEM, FTIR and TPD-NH3 techniques. The physicochemical analysis showed that with NH4CI treatment, the specific surface area of clinoptilolite increased obviously, while its crystallinity decreased slightly. It was found that the crystallinity of clinoptilolite was dramatically changed, whereas crystallinity of CuO has not been influenced significantly by the increase of CZA content. Moreover, with increasing the CZA/Clinoptilolite ratio, the specific surface area of nanocatalysts decreased. It is shown that the CZA particle size is distributed between 30.5-131.2 nm with an average size of 70.6 nm in which 77.8% of the particles are in the range of below 100 nm. The TPD-NH3 patterns showed that the number of the acid sites of the nanocatalysts decreased with the increase the CZA content. The influence of reaction pressure was investigated, confirming that the optimal reaction pressure for this catalyst was 40 bar. The catalytic performance is shown that the CZA/Clinoptilolite = 2 nanocatalyst had higher activity, selectivity due to its higher acidic sites. PMID:23901522

Khoshbin, Reza; Haghighi, Mohammad

2013-07-01

82

The effect of annealing on the photoluminescence of epitaxial DMe-PTCDI multilayers on Ag(110)  

Microsoft Academic Search

Epitaxial multilayer structures of DMe-PTCDI (2,9-dimethyl-antra[2,1,9-def:6,5,10-d?e?f?]diisoquinoline-1,3,8,10-tetrone) on Ag(110) were prepared by molecular beam epitaxy. Photoluminescence spectra obtained under ultra high vacuum (UHV) conditions of the multilayers show significant polarisation dependence. By combining this result with a real space model derived from low energy electron diffraction (LEED) measurements the molecular transition dipole moment was determined. During an annealing process the fluorescence

A. H. Schäfer; C. Seidel; H. Fuchs

2000-01-01

83

Oriented growth of DMe-PTCDI on Ag(110); an LEED, XPS, SFM and STM characterisation  

Microsoft Academic Search

Epitaxial monolayer and multilayer structures of DMe-PTCDI (of 2,9-dimethyl-antra [2,1,9-def:6,5,10-d?e?f?]diisoquinoline-1,3,8,10-tetrone) were prepared on Ag(110) by molecular beam epitaxy. This work presents structural and electron photoemission data for further investigations where highly laterally oriented multilayer films are important. Preparation conditions for five highly ordered monolayer and two multilayer structures are presented. LEED images taken during preparation show the transitions between the

C. Seidel; A. H. Schäfer; H. Fuchs

2000-01-01

84

Synthesis, NMR and properties of a novel crown ether dimer: X-ray molecular structure of bis(2, 5-dimethoxy-4,6-dimethyl-1,3-xylyl)-18-crown-4  

Microsoft Academic Search

The synthesis and complete characterization of the precursor diol 3 and that of the crown ether 4 are reported. Further the X-ray structure of this novel crown ether is included, which provide us with valuable information about its solid-state structure. The title molecule lies about a centre of symmetry. Thus the novel 18-membered macrocycle 4 has a symmetrical configuration. Interestingly,

Hani Amouri; Yvon Besace; Jacqueline Vaissermann

2003-01-01

85

High octane ethers from synthesis gas-derived alcohols. Quarterly technical progress report, April--June 1993  

SciTech Connect

The results shown in Figures 10 and 11 demonstrate that the formation of butenes was very sensitive to the alcohol partial pressure. A small elevation of the alcohol pressure suppressed the formation of butenes rather drastically at both 90 and 117{degree}C. The synthesis rates of DME, MIBE, and MTBE ethers were not significantly affected at 90{degree}C, although there was a trend to increase the space time yield of DME as the alcohol pressure was increased. At the reaction temperature of 117{degree}C, all of the ethers showed increasing productivities as the pressure of the reactants was increased (Figure 11). An isotope labelling experiment was carried out to provide mechanistic insight into the manner in which methanol and isobutanol react together to form DME, MIBE, and MTBE ethers and to determine if MTBE were derived from MIBE.

Klier, K.; Herman, R.G.; Menszak, J.; Johansson, M.A.; Feeley, O.C.; Kim, D.

1993-07-01

86

Intermolecular Interaction Between CO or CO{_2} and Ether or Thioether or Propylene Oxide in a Complex, Investigated by Fourier Transform Microwave Spectroscopy and AB Initio Calculations  

NASA Astrophysics Data System (ADS)

In sharp contrast with the hydrogen bond, which has beenwell established to be one of the strongest interactions between two atomic and/or molecular species, weak interactions between two closed-shell molecules have not been understood in detail. We have thus carried out a systematic study on complexes shown in the title; examples include the CO-ethylene oxide (EO), CO-ethylene sulfide (ES), CO-dimethyl ether (DME), CO-dimehtyl sulfide (DMS), CO{_2}-EO, CO{_2}-ES, CO{_2}-DME, and CO{_2}-propylene oxide (PO) complexes. From their Fourier transform microwave spectra, we determined the {RS} structure, the force constant of the van der Waals stretching mode, and the dissociation energy by analyzing the observed rotational and centrifugal distortion constants. We have also carried out ab initio molecular orbital calculations at the level of MP2 with basis sets 6-311++G(d, p) and aug-cc-pVDZ using the Gaussian 09 package. In most cases, the MP2/6-311++G(d, p) calculations yield rotational constants in better agreement with the experimental values, than the other basis set, in other word, the molecular structures calculated using this basis set are close to those experimentally found for the ground state. The estimated bond dissociation energies including the zero-point vibrational energy corrections ?ZPV and the basis set superposition errors (BSSE) calculated with the counterpoise correction (CP) are in good agreement with the observed binding energies {E_B}. We have applied an NBO analysis to the complexes to calculate the stabilization energy CT (= ?E{??*}), which we found are closely correlated with the binding energies {E_B}. We have thus achieved a consistent overview on the intermolecular interaction in the complexes under consideration.

Kawashima, Yoshiyuki; Orita, Yukari; Sato, Akinori; Hirota, Eizi

2011-06-01

87

Conversion of Biomass Syngas to DME Using a Microchannel Reactor  

SciTech Connect

The capability of a microchannel reactor for direct synthesis of dimethylether (DME) from biomass syngas was explored. The reactor was operated in conjunction with a hybrid catalyst system consisting of methanol synthesis and dehydration catalysts, and the influence of reaction parameters on syngas conversion was investigated. The activities of different dehydration catalysts were compared under DME synthesis conditions. Reaction temperature and pressure exhibited similar positive effects on DME formation. A catalytic stability test of the hybrid catalyst system was performed for 880 hours, during which CO conversion only decreased from 88% to 81%. In the microchannel reactor, the catalyst deactivation rate appeared to be much slower than in a tubular fixed-bed reactor tested for comparison. Test results also indicated that the dehydration reaction rate and the water depletion rate via a water-gas-shift reaction should be compatible in order to achieve high selectivity to DME. Using the microchannel reactor, it was possible to achieve a space time yield almost three times higher than commercially demonstrated performance results. A side-by-side comparison indicated that the heat removal capability of the microchannel reactor was at least six times greater than that of a commercial slurry reactor under similar reaction conditions.

Hu, Jianli; Wang, Yong; Cao, Chunshe; Elliott, Douglas C.; Stevens, Don J.; White, James F.

2005-03-01

88

Pressure-driven neutral-ionic transition in ClMePD-DMeDCNQI  

NASA Astrophysics Data System (ADS)

Application of about 0.8 GPa pressure is sufficient to induce the neutral-ionic transition in the mixed stack charge-transfer crystal 2-chloro-5-methyl-p-phenylenediamine-2,5-dimethyl-dicyanoquinonediimine (ClMePD-DMeDCNQI). The ionicity increases continuously from ~0.35 at ambient conditions to ~0.65 when the pressure is raised up to 2 GPa. Moreover, stack dimerization begins well before the crossing of the neutral-ionic interface. The evolution of the transition is similar to what observed in the temperature-induced phase change in the same compound. A distinguishing feature is represented by the simultaneous presence of domains of molecules with slightly different ionicities across the transition pressure. A comparison of the present example of a pressure-driven neutral-ionic transition with the well-studied cases of tetrathiafulvalene-chloranil and of tetrathiafulvalene-2,5-dichloro-p-benzoquinone puts in evidence the remarkably different evolution of the three transitions.

Farina, Luca; Brillante, Aldo; Masino, Matteo; Girlando, Alberto

2001-10-01

89

Optical and photovoltaic properties of thin films of N, N?-dimethyl-3,4,9,10-perylenetetracarboxylic acid diimide  

Microsoft Academic Search

The morphology of thin films of N,N?-dimethyl-3,4,9,10-perylenetetracarboxylic acid diimide (DMe-PTCDI), vacuum deposited onto quartz substrates, kept at various temperatures (Ts) between 300 and 450 K, was investigated by the Atomic Force Microscopy. The samples were polycrystalline, with no appreciable amount of amorphous phase. Below Ts=330 K, the dominating forms are oval crystallites, whereas above this temperature ribbon-like crystallites prevail. Optical spectra of

Ya. Vertsimakha; P. Lutsyk; K. Palewska; J. Sworakowski; O. Lytvyn

2007-01-01

90

New V and V Tools for Diagnostic Modeling Environment (DME)  

NASA Technical Reports Server (NTRS)

The purpose of this report is to provide correctness and reliability criteria for verification and validation (V&V) of Second Generation Reusable Launch Vehicle (RLV) Diagnostic Modeling Environment, describe current NASA Ames Research Center tools for V&V of Model Based Reasoning systems, and discuss the applicability of Advanced V&V to DME. This report is divided into the following three sections: (1) correctness and reliability criteria; (2) tools for V&V of Model Based Reasoning; and (3) advanced V&V applicable to DME. The Executive Summary includes an overview of the main points from each section. Supporting details, diagrams, figures, and other information are included in subsequent sections. A glossary, acronym list, appendices, and references are included at the end of this report.

Pecheur, Charles; Nelson, Stacy; Merriam, Marshall (Technical Monitor)

2002-01-01

91

Bridging the dMe Gap with Ross 154  

NASA Astrophysics Data System (ADS)

M dwarf flare (dMe) stars provide excellent laboratories for the study of magnetic flaring activity, coronal heating, and chemical fractionation mechanisms. Quiescent element abundances seem to be tied to the first ionization potential (FIP), but the nature of that dependence varies with the stellar activity level, whether the emission is quiescent or flaring, and other factors. Understanding flare abundances is important because much of coronal `quiescent' emission is likely the result of continuous X-class `microflares'. Only eight late-type dMe systems have been studied using XMM or Chandra gratings, and a large gap exists between low- and high-activity versions of those stars that can only be bridged with an observation of Ross 154.

Wargelin, Bradford

2008-10-01

92

Updating inertial navigation systems with VOR/DME information.  

NASA Technical Reports Server (NTRS)

Demonstration that updating an inertial navigation system (INS) with VOR/DME information (from one or two stations) by means of a maximum-likelihood filter results in substantial improvements in navigational accuracy over that obtained by the use of a single VOR/DME (current practice). When continuously updating, the use of a high-quality INS (0.01 deg/hr gyro drift) instead of a low-quality INS (1.0 deg/hr gyro drift) does not substantially improve position accuracy. In-flight alignment (or realignment) of an INS to an accuracy comparable to that of ground alignment can be accomplished by using two DMEs. Several reduced-order suboptimal filters were found to perform nearly optimally.

Bobick, J. C.; Bryson, A. E., Jr.

1972-01-01

93

Temperature-induced neutral-ionic transition in 2-chloro-5-methyl-p-phenylenediamine-2,5-dimethyl-dicyanoquinonediimine  

NASA Astrophysics Data System (ADS)

A mixed-stack organic charge-transfer crystal of 2-chloro-5-methyl- p-phenylenediamine-2,5-dimethyl dicyanoquinonediimine (ClMePD-DMeDCNQI), which undergoes a temperature-induced neutral-ionic transition (TINIT), is reported. From infrared spectroscopy, the molecular ionicity (?) of ClMePD-DMeDCNQI was found to change continuously from ?=0.3 at 300 K to ?=0.6 at 100 K. The neutral-ionic interface was crossed without a discontinuity in ? at around 200 K, accompanied by stack dimerization. These features were quite different from the discontinuous change in ? observed for the TINIT of tetrathiafulvalene-p-chloranil (TTF-CA) and tetramethylbenzidine-tetracyanoquinodimethane (TMB-TCNQ). The transition characteristics in ClMePD-DMeDCNQI are discussed by drawing a comparison with those seen in TTF-CA and TMB-TCNQ.

Aoki, Shinya; Nakayama, Toshio

1997-08-01

94

DME: Documentation Management Environment for Software Product Lines Tool Demo Proposal  

E-print Network

DME: Documentation Management Environment for Software Product Lines ­ Tool Demo Proposal Ha Duy://www.comp.nus.edu.sg/~stan/DME-video.html ABSTRACT Similar documents arise in software and business situations. Examples are user guides for different versions of a software product, contracts between vendors and clients, and legal documents

Jarzabek, Stan

95

The study of a barley epigenetic regulator, HvDME, in seed development and under drought  

PubMed Central

Background Epigenetic factors such as DNA methylation and histone modifications regulate a wide range of processes in plant development. Cytosine methylation and demethylation exist in a dynamic balance and have been associated with gene silencing or activation, respectively. In Arabidopsis, cytosine demethylation is achieved by specific DNA glycosylases, including AtDME (DEMETER) and AtROS1 (REPRESSOR OF SILENCING1), which have been shown to play important roles in seed development. Nevertheless, studies on monocot DNA glycosylases are limited. Here we present the study of a DME homologue from barley (HvDME), an agronomically important cereal crop, during seed development and in response to conditions of drought. Results An HvDME gene, identified in GenBank, was found to encode a protein with all the characteristic modules of DME-family DNA glycosylase proteins. Phylogenetic analysis revealed a high degree of homology to other monocot DME glycosylases, and sequence divergence from the ROS1, DML2 and DML3 orthologues. The HvDME gene contains the 5? and 3? Long Terminal Repeats (LTR) of a Copia retrotransposon element within the 3? downstream region. HvDME transcripts were shown to be present both in vegetative and reproductive tissues and accumulated differentially in different seed developmental stages and in two different cultivars with varying seed size. Additionally, remarkable induction of HvDME was evidenced in response to drought treatment in a drought-tolerant barley cultivar. Moreover, variable degrees of DNA methylation in specific regions of the HvDME promoter and gene body were detected in two different cultivars. Conclusion A gene encoding a DNA glycosylase closely related to cereal DME glycosylases was characterized in barley. Expression analysis during seed development and under dehydration conditions suggested a role for HvDME in endosperm development, seed maturation, and in response to drought. Furthermore, differential DNA methylation patterns within the gene in two different cultivars suggested epigenetic regulation of HvDME. The study of a barley DME gene will contribute to our understanding of epigenetic mechanisms operating during seed development and stress response in agronomically important cereal crops. PMID:24175960

2013-01-01

96

Poly(arylene ether)s containing pendent ethynyl groups  

NASA Technical Reports Server (NTRS)

Poly(arylene ether)s containing pendent ethynyl and substituted ethynyl groups and poly(arylene ether) copolymers containing pendent ethynyl and substituted ethynyl groups are readily prepared from bisphenols containing ethynyl and substituted ethynyl groups. The resulting polymers are cured up to 350.degree. C. to provide crosslinked poly(arylene ether)s with good solvent resistance, high strength and modulus.

Hergenrother, Paul M. (Inventor); Jensen, Brian J. (Inventor)

1996-01-01

97

EtherNET vs. EtherNOT  

Microsoft Academic Search

A panel will discuss how data centers and high performance computing systems currently use two main classes of interconnection networks. Those based on the Ethernet protocol (EtherNET) and those with proprietary protocols (EtherNOT means Infiniband, Infiniband variants such as PathScale and Cray XD1, Quadrics, Myricom, etc.). While Ethernet can be considered a commodity product, other specialized systems can achieve better

Fabrizio Petrini

2005-01-01

98

Sustainable use of California biomass resources can help meet state and national bioenergy targets  

E-print Network

Ethanol Mixed alcohols Dimethyl ether Bio-oils (pyrolysisethanol, mixed alco- hols, dimethylether (DME), bio-oils andoils) Alkanes (catalytic) Liquid Ethanol Butanol Other alcohols Mixed alcohols Liquified biomethane (LNG) [Bio

Jenkins, Bryan M; Williams, Robert B; Gildart, Martha C; Kaffka, Stephen R.; Hartsough, Bruce; Dempster, Peter G

2009-01-01

99

A DME Based Area Navigation Systems for GPS/WAAS Interference Mitigation In General Aviation Applications  

E-print Network

(inertial, air- data and magnetometers) is shown to provide an af- fordable area navigation capability-DME infrastructure is around $84 Million 3]. Eliminating or reducing the num- ber of active ground based navigaitonal

Stanford University

100

Crown ethers in graphene  

NASA Astrophysics Data System (ADS)

Crown ethers are at their most basic level rings constructed of oxygen atoms linked by two- or three-carbon chains. They have attracted attention for their ability to selectively incorporate various atoms or molecules within the cavity formed by the ring. However, crown ethers are typically highly flexible, frustrating efforts to rigidify them for many uses that demand higher binding affinity and selectivity. Here we present atomic-resolution images of the same basic structures of the original crown ethers embedded in graphene. This arrangement constrains the crown ethers to be rigid and planar. First-principles calculations show that the close similarity of the structures should also extend to their selectivity towards specific metal cations. Crown ethers in graphene offer a simple environment that can be systematically tested and modelled. Thus, we expect that our finding will introduce a new wave of investigations and applications of chemically functionalized graphene.

Guo, Junjie; Lee, Jaekwang; Contescu, Cristian I.; Gallego, Nidia C.; Pantelides, Sokrates T.; Pennycook, Stephen J.; Moyer, Bruce A.; Chisholm, Matthew F.

2014-11-01

101

Crown ethers in graphene.  

PubMed

Crown ethers are at their most basic level rings constructed of oxygen atoms linked by two- or three-carbon chains. They have attracted attention for their ability to selectively incorporate various atoms or molecules within the cavity formed by the ring. However, crown ethers are typically highly flexible, frustrating efforts to rigidify them for many uses that demand higher binding affinity and selectivity. Here we present atomic-resolution images of the same basic structures of the original crown ethers embedded in graphene. This arrangement constrains the crown ethers to be rigid and planar. First-principles calculations show that the close similarity of the structures should also extend to their selectivity towards specific metal cations. Crown ethers in graphene offer a simple environment that can be systematically tested and modelled. Thus, we expect that our finding will introduce a new wave of investigations and applications of chemically functionalized graphene. PMID:25391367

Guo, Junjie; Lee, Jaekwang; Contescu, Cristian I; Gallego, Nidia C; Pantelides, Sokrates T; Pennycook, Stephen J; Moyer, Bruce A; Chisholm, Matthew F

2014-01-01

102

Performance of an Ar-DME imaging photoelectric polarimeter  

NASA Astrophysics Data System (ADS)

The possibility to perform polarimetry in the soft X-ray energy band (2-10 keV) with the Gas Pixel Detector, filled with low Z mixtures, has been widely explored so far. The possibility to extend the technique to higher energies, in combination with multilayer optics, has been also hypothesized in the past, on the basis of simulations. Here we present a recent development to perform imaging polarimetry between 6 and 35 keV, employing a new design for the GPD, filled with a Ar-DME gas mixture at high pressure. In order to improve the efficiency by increasing the absorption gap, while preserving a good parallel electric field, we developed a new configuration characterized by a wider gas cell and a wider GEM. The uniform electric field allows to maintain high polarimetric capabilities without any decrease of spectroscopic and imaging properties. We present the first measurements of this prototype showing that it is now possible to perform imaging and spectro-polarimetry of hard X-ray sources.

Fabiani, S.; Bellazzini, R.; Berrilli, F.; Brez, A.; Costa, E.; Minuti, M.; Muleri, F.; Pinchera, M.; Rubini, A.; Soffitta, P.; Spandre, G.

2012-09-01

103

Simultaneous determination of six hydrophilic ethers at trace levels using coconut charcoal adsorbent and gas chromatography/mass spectrometry.  

PubMed

The main objective of the following study was to determine the efficiency of a method that uses coconut charcoal as a solid-phase extraction (SPE) adsorbent in order to simultaneously detect six hydrophilic ether species in water in the low microgram-per-liter range. The applied method was validated for quantification of ethyl tert-butyl ether, 1,4-dioxane, ethylene glycol dimethyl ether (monoglyme), diethylene glycol dimethyl ether (diglyme), triethylene glycol dimethyl ether (triglyme) and tetraethylene glycol dimethyl ether (tetraglyme). SPE followed by gas chromatography/mass spectrometry of the extracts using the selected ion monitoring mode allowed for establishing low detection limits in the range of 0.007-0.018 ?g/L in ultrapure water and 0.004-0.020 ?g/L in environmental samples. Examination of the method accuracy and precision resulted in a recovery greater than 86.8 % for each compound with a relative standard deviation of less than 6.6 %. A stability study established a 5-day holding time for the unpreserved water samples and extracts. Finally, 27 samples obtained from surface water bodies in Germany were analyzed for the six hydrophilic ethers. Each analyte was detected in at least eight samples at concentrations reaching 2.0 ?g/L. The results of this study emphasize the advantage of the method to simultaneously determine six hydrophilic ether compounds. The outcome of the surface water analyses augments a concern about their frequent and significant presence in surface water bodies in Germany. PMID:23232954

Stepien, D K; Püttmann, W

2013-02-01

104

Functional and Expression Analysis of the Metal-Inducible dmeRF System from Rhizobium leguminosarum bv. viciae  

PubMed Central

A gene encoding a homolog to the cation diffusion facilitator protein DmeF from Cupriavidus metallidurans has been identified in the genome of Rhizobium leguminosarum UPM791. The R. leguminosarum dmeF gene is located downstream of an open reading frame (designated dmeR) encoding a protein homologous to the nickel- and cobalt-responsive transcriptional regulator RcnR from Escherichia coli. Analysis of gene expression showed that the R. leguminosarum dmeRF genes are organized as a transcriptional unit whose expression is strongly induced by nickel and cobalt ions, likely by alleviating the repressor activity of DmeR on dmeRF transcription. An R. leguminosarum dmeRF mutant strain displayed increased sensitivity to Co(II) and Ni(II), whereas no alterations of its resistance to Cd(II), Cu(II), or Zn(II) were observed. A decrease of symbiotic performance was observed when pea plants inoculated with an R. leguminosarum dmeRF deletion mutant strain were grown in the presence of high concentrations of nickel and cobalt. The same mutant induced significantly lower activity levels of NiFe hydrogenase in microaerobic cultures. These results indicate that the R. leguminosarum DmeRF system is a metal-responsive efflux mechanism acting as a key element for metal homeostasis in R. leguminosarum under free-living and symbiotic conditions. The presence of similar dmeRF gene clusters in other Rhizobiaceae suggests that the dmeRF system is a conserved mechanism for metal tolerance in legume endosymbiotic bacteria. PMID:23934501

Rubio-Sanz, L.; Prieto, R. I.; Imperial, J.; Brito, B.

2013-01-01

105

Why are dimethyl sulfoxide and dimethyl sulfone such good solvents?  

PubMed

We have carried out B3PW91 and MP2-FC computational studies of dimethyl sulfoxide, (CH(3))(2)SO, and dimethyl sulfone, (CH(3))(2)SO(2). The objective was to establish quantitatively the basis for their high polarities and boiling points, and their strong solvent powers for a variety of solutes. Natural bond order analyses show that the sulfur-oxygen linkages are not double bonds, as widely believed, but rather are coordinate covalent single S(+)-->O(-) bonds. The calculated electrostatic potentials on the molecular surfaces reveal several strongly positive and negative sites (the former including sigma-holes on the sulfurs) through which a variety of simultaneous intermolecular electrostatic interactions can occur. A series of examples is given. In terms of these features the striking properties of dimethyl sulfoxide and dimethyl sulfone, their large dipole moments and dielectric constants, their high boiling points and why they are such good solvents, can readily be understood. PMID:18458968

Clark, Timothy; Murray, Jane S; Lane, Pat; Politzer, Peter

2008-08-01

106

Propenyl ether monomers for photopolymerization  

DOEpatents

Propenyl ether monomers of formula A(OCH{double_bond}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 the above formula 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.

Crivello, J.V.

1996-10-22

107

Propenyl ether monomers for photopolymerization  

DOEpatents

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.

Crivello, James V. (Clifton Park, NY)

1996-01-01

108

http://informatics.medicine.dal.ca http://dme.medicine.dal.ca  

E-print Network

http://informatics.medicine.dal.ca http://dme.medicine.dal.ca www.medicine.dal.ca www.dal.ca Dalhousie University, Division of Medical Education Faculty Position, Tenure Stream, Medical Informatics Program The Division invites applications for a tenure-stream faculty position in Medical Informatics

Adl, Sina

109

76 FR 13438 - AccessTel, Inc., American Asset Management Corp., DME Interactive Holdings, Inc., DocuPort, Inc...  

Federal Register 2010, 2011, 2012, 2013, 2014

...File No. 500-1] AccessTel, Inc., American Asset Management Corp., DME Interactive Holdings, Inc., DocuPort...information concerning the securities of American Asset Management Corp. because it has not filed any periodic...

2011-03-11

110

Fourier transform microwave spectrum of the CO-dimethyl sulfide complex  

NASA Astrophysics Data System (ADS)

The rotational spectrum of the CO-dimethyl sulfide (DMS) complex was measured in the frequency region from 4.8 up to 25 GHz by Fourier transform microwave spectroscopy. For the normal species 27 a-type and 57 c-type transitions were observed, while 16 and 8 c-type transitions were assigned for the species with 34S and 13C in the DMS moiety, respectively, in natural abundance. In addition, 7 a-type and 48 c-type transitions were assigned for the complex with the 13CO enriched species as a component and 9 a-type and 42 c-type transitions for the complex with enriched C 18O. No splitting was observed, which could be ascribed to the tunneling motion of the CO between two possible potential minima around DMS, while many transitions were split by the internal-rotation of the two methyl tops of the DMS unit. In cases where the K-type splitting was close to the methyl internal-rotation splitting, forbidden transitions were observed which apparently followed b-type selection rules. All of the observed transition frequencies for the normal species were analyzed simultaneously using a two-top internal-rotation and rotation Hamiltonian. The potential barrier height V3 to internal rotation of the methyl groups of the DMS was determined to be 745.5 (30) cm -1. The transition frequencies observed for all the isotopomers were analyzed using an asymmetric-rotor rotational Hamiltonian, to determine rotational and centrifugal distortion constants. The rs coordinates calculated from the observed rotational constants led to the conclusion that the CO moiety was located in a plane perpendicular to the skeletal plane of the DMS and bisecting its CSC angle. This structure of the CO-DMS is very much different from that of the CO-DME, in which the CO is located in the DME skeletal plane. The distance between the centers of gravity of the two moieties, Rcm, was calculated to be 3.789 Å for the CO-DMS, which is longer by only 0.11 Å than that in the CO-DME complex: 3.68 Å, in spite of the fact that the van der Waals radius of the S atom is much larger than that of the O atom. The small difference in Rcm is, in part, ascribed to the location of the CO relative to the DMS/DME. The more important reason is that the intermolecular bonding of the CO-DMS is stronger than that of CO-DME; by assuming a Lennard-Jones-type potential, the force constant of the van der Waals stretching mode and the dissociation energy were estimated to be 2.7 Nm -1 and 3.3 kJ mol -1, respectively, which were larger than those of the CO-DME: 1.4 Nm -1 and 1.6 kJ mol -1.

Sato, Akinori; Kawashima, Yoshiyuki; Hirota, Eizi

2010-10-01

111

How is the Diamagnetic Effect (DME) Relevant to Stellar Surface Phenomena?  

E-print Network

The structure of stellar atmospheres can be modified if they include embedded diverging magnetic fields. This is due to the presence of speed filters. Here we examine some of the relevant effects through the numerical simulation of the motion of charged particles. We introduce the concept of "floating" particles and point out the relevance of the diamagnetic effet (DME) to the evolution of Maxwellian velocity distributions into Non-Maxwellian.

Netzach Farbiash; Raphael Steinitz

2005-01-09

112

Isobutanol coupling with ethanol and methanol to ethers over sulfonated resin catalysts: Activities and selectivities  

SciTech Connect

The synthesis of C{sub 5}-C{sub 8} ethers from mixtures of C{sub 1}-C{sub 4} alcohols over strong acid Amberlyst resin catalysts has been initiated, and the overall activity pattern of the resins was found to be Amberlyst-35 > Amberlyst-36 > Amberlyst-15 > Amberlyst-1010, all of which were more active than Nafion-H. With methanol/isobutanol reactants, it was observed that increasing the reaction pressure strongly decreased the space time yield and selectivity of the butenes, principally isobutene, while tending to increase the space time yield of the ethers methylisobutylether (MIBE), methyl tertiarybutyl ether (MTBE), and dimethylether (DME). Other reactant mixtures utilized at high flow rates included ethanol/isobutanol, where EIBE and ETBE were products. Upon increasing the isobutanol/ethanol ratio above 1/1, it was shown that diethylether (DEE) formation decreased but the synthesis of tertiarybutyl isobutylether (TBIBE) increased. A reactant mixture of ethanol/isopropanol was also investigated, and dehydration of the isopropanol readily occurred to form propene and coupling gave diisoproplyether (DIPE) as the dominant product at 90{degrees}C.

Herman, R.G.; Klier, K.; Feeley, O.C. [Lehigh Univ., Bethlehem, PA (United States)

1994-12-31

113

Imide/Arylene Ether Copolymers  

NASA Technical Reports Server (NTRS)

New imide/arylene ether copolymers prepared by reacting anhydride-terminated poly(amic acids) with amine-terminated poly(arylene ethers) in polar aprotic solvents. Each resulting copolymer may have one glass-transition temperature or two, depending on chemical structure and/or compatibility of block units. Most of copolymers form tough, solvent-resistant films with high tensile properties. Films cast from solution tough and flexible, and exhibit useful thermal and mechanical properties. Potentially useful as moldings, adhesives, or composite matrices. Because of flexible arylene ether blocks, these copolymers easier to process than polyimides.

Jensen, Brian J.; Hergenrother, Paul M.; Bass, Robert G.

1991-01-01

114

Einstein's Thoughts on the Ether  

NSDL National Science Digital Library

Do light waves travel through the ether like waves on a lake travel through water? In this video segment adapted from NOVA, a young Albert Einstein grapples with this question while examining the speed of light.

2004-02-20

115

40 CFR 721.10099 - Dialkyl dimethyl ammonium carbonate (generic).  

Code of Federal Regulations, 2010 CFR

...2010-07-01 false Dialkyl dimethyl ammonium carbonate (generic). 721.10099...Substances § 721.10099 Dialkyl dimethyl ammonium carbonate (generic). (a) Chemical...identified generically as dialkyl dimethyl ammonium carbonate (1:1) (PMN...

2010-07-01

116

40 CFR 721.333 - Dimethyl alkylamine salt (generic).  

Code of Federal Regulations, 2014 CFR

...2014-07-01 false Dimethyl alkylamine salt (generic). 721.333 Section 721...Substances § 721.333 Dimethyl alkylamine salt (generic). (a) Chemical substance...identified generically as a Dimethyl alkylamine salt (PMNs P-99-0368 and...

2014-07-01

117

40 CFR 721.333 - Dimethyl alkylamine salt (generic).  

Code of Federal Regulations, 2012 CFR

...2012-07-01 false Dimethyl alkylamine salt (generic). 721.333 Section 721...Substances § 721.333 Dimethyl alkylamine salt (generic). (a) Chemical substance...identified generically as a Dimethyl alkylamine salt (PMNs P-99-0368 and...

2012-07-01

118

40 CFR 721.333 - Dimethyl alkylamine salt (generic).  

Code of Federal Regulations, 2011 CFR

...2011-07-01 false Dimethyl alkylamine salt (generic). 721.333 Section 721...Substances § 721.333 Dimethyl alkylamine salt (generic). (a) Chemical substance...identified generically as a Dimethyl alkylamine salt (PMNs P-99-0368 and...

2011-07-01

119

40 CFR 721.333 - Dimethyl alkylamine salt (generic).  

Code of Federal Regulations, 2010 CFR

...2010-07-01 false Dimethyl alkylamine salt (generic). 721.333 Section 721...Substances § 721.333 Dimethyl alkylamine salt (generic). (a) Chemical substance...identified generically as a Dimethyl alkylamine salt (PMNs P-99-0368 and...

2010-07-01

120

Imide/arylene ether copolymers  

NASA Technical Reports Server (NTRS)

Imide/arylene ether block copolymers are prepared by reacting anhydride terminated poly(amic acids) with amine terminated poly(arylene ethers) in polar aprotic solvents and by chemically or thermally cyclodehydrating the resulting intermediate poly(amic acids). The resulting block copolymers have one glass transition temperature or two, depending upon the particular structure and/or the compatibility of the block units. Most of these block copolymers form tough, solvent resistant films with high tensile properties.

Jensen, Brian J. (inventor); Hergenrother, Paul M. (inventor); Bass, Robert G. (inventor)

1992-01-01

121

Photodissociation dynamics of dimethyl disulfide  

NASA Astrophysics Data System (ADS)

We present the resonance Raman spectrum of dimethyl disulfide excited with 266 nm laser light. The spectrum contains a progression of ten peaks assigned to the C-S stretch mode. This suggests that the initial motion of the dissociating molecule out of the Franck-Cordon region stretches the C-S bond. This interpretation is supported by semi-empirical calculations of the first excited singlet potential energy surface. The calculations suggest the next highest excited singlet state dissociates along the S-S bond, in agreement with work at shorter wavelengths by other workers.

Rinker, Adam; Halleman, Christopher D.; Wedlock, Michael R.

2005-10-01

122

Ether lipids based on the glyceryl ether skeleton: Present state, future potential  

Microsoft Academic Search

Lipids from natural sources consist mainly of saponifiable substances, such as glycerides, along with some unsaponifiable\\u000a lipids, some of which are ether lipids. Typical ether lipids are monoalkyl ethers of glycerin, also called alkyl\\/alkenyl glyceryl\\u000a ethers. Alkyl\\/alkenyl glyceryl ethers have also been reported in marine organisms and in human feces. Several chemical syntheses\\u000a of such ether lipids have been reported.

Kouichi Urata; Naotake Takaishi

1996-01-01

123

210 X 297mm Dimethyl Carbonate  

E-print Network

-chloride and dimethly-sulfuric acid for carbonylation and methylation reactions. Reactive distillation process Development for the Continuous Production of Dimethyl Carbonate by Reactive Distillation () 20004 . 11 for the Continuous Production of Dimethyl Carbonate by Reactive Distillation 2001 . 10 . 1 . 2004 . 9 . 30

Hong, Deog Ki

124

Isotopic analysis of dimethyl selenide  

SciTech Connect

The separated isotopes of selenium may be used as stable precursors for the synthesis of radio-bromine isotopes for positron emitter tomographic diagnostics. As part of a project to find a suitable distillation method for separating selenium isotopes, the need arose to study the organo-metallic compound dimethyl selenide. The complexity of the mass spectrum tended to obscure the isotope effect with 35 major peaks being measured. A least-squares fitting procedure was developed for the 13 fragmentation factors as well as a few hundredths of a percent, yet no sizeable separation was observed across the test column. According to these measurements, the effect of one mass unit increase in the selenium isotope results in less than 10 ppM in the vapor pressure of the compound. 4 figures.

McInteer, B.B.

1984-01-01

125

A new mechanism for the aerobic catabolism of dimethyl sulfide.  

PubMed Central

Aerobic degradation of dimethyl sulfide (DMS), previously described for thiobacilli and hyphomicrobia, involves catabolism to sulfide via methanethiol (CH3SH). Methyl groups are sequentially eliminated as HCHO by incorporation of O2 catalyzed by DMS monooxygenase and methanethiol oxidase. H2O2 formed during CH3SH oxidation is destroyed by catalase. We recently isolated Thiobacillus strain ASN-1, which grows either aerobically or anaerobically with denitrification on DMS. Comparative experiments with Thiobacillus thioparus T5, which grows only aerobically on DMS, indicate a novel mechanism for aerobic DMS catabolism by Thiobacillus strain ASN-1. Evidence that both organisms initially attacked the methyl group, rather than the sulfur atom, in DMS was their conversion of ethyl methyl sulfide to ethanethiol. HCHO transiently accumulated during the aerobic use of DMS by T. thioparus but not with Thiobacillus strain ASN-1. Catalase levels in cells grown aerobically on DMS were about 100-fold lower in Thiobacillus strain ASN-1 than in T. thioparus T5, suggesting the absence of H2O2 formation during DMS catabolism. Also, aerobic growth of T. thioparus T5 on DMS was blocked by the catalase inhibitor 3-amino-1,2,4-triazole whereas that of Thiobacillus strain ASN-1 was not. Methyl butyl ether, but not CHCl3, blocked DMS catabolism by T. thioparus T5, presumably by inhibiting DMS monooxygenase and perhaps methanethiol oxidase. In contrast, DMS metabolism by Thiobacillus strain ASN-1 was unaffected by methyl butyl ether but inhibited by CHCl3. DMS catabolism by Thiobacillus strain ASN-1 probably involves methyl transfer to a cobalamin carrier and subsequent oxidation as folate-bound intermediates. PMID:8285684

Visscher, P T; Taylor, B F

1993-01-01

126

Removal of methanethiol, dimethyl sulfide, dimethyl disulfide, and hydrogen sulfide from contaminated air by Thiobacillus thioparus TK-m.  

PubMed Central

Methanethiol, dimethyl sulfide, dimethyl disulfide, and hydrogen sulfide were efficiently removed from contaminated air by Thiobacillus thioparus TK-m and oxidized to sulfate stoichiometrically. More than 99.99% of dimethyl sulfide was removed when the load was less than 4.0 g of dimethyl sulfide per g (dry cell weight) per day. PMID:2930168

Kanagawa, T; Mikami, E

1989-01-01

127

Catalytic Consequences of Acid Strength in the Conversion of Methanol to Dimethyl Ether  

SciTech Connect

The effects of acid identity on CH{sub 3}OH dehydration are examined here using density functional theory (DFT) estimates of acid strength (as deprotonation energies, DPE) and reaction energies, combined with rate data on Keggin polyoxometalate (POM) clusters and zeolite H-BEA. Measured first-order (k{sub mono}) and zero-order (k{sub dimer}) CH3OH dehydration rate constants depend exponentially on DPE for POM clusters; the value of k{sub mono} depends more strongly on DPE than k{sub dimer} does. The chemical significance of these rate parameters and the basis for their dependences on acid strength were established by using DFT to estimate the energies of intermediates and transition states involved in elementary steps that are consistent with measured rate equations. We conclude from this treatment that CH{sub 3}OH dehydration proceeds via direct reactions of co-adsorbed CH{sub 3}OH molecules for relevant solid acids and reaction conditions. Methyl cations formed at ion-pair transition states in these direct routes are solvated by H{sub 2}O and CH{sub 3}OH more effectively than those in alternate sequential routes involving methoxide formation and subsequent reaction with CH{sub 3}OH. The stability of ion-pairs, prevalent as intermediates and transition states on solid acids, depends sensitively on DPE because of concomitant correlations between the stability of the conjugate anionic cluster and DPE. The chemical interpretation of k{sub mono} and k{sub dimer} from mechanism-based rate equations, together with thermochemical cycles of their respective transition state formations, show that similar charge distributions in the intermediate and transition state involved in k{sub dimer} cause its weaker dependence on DPE. Values of k{sub mono} involve uncharged reactants and the same ion-pair transition state as k{sub dimer}; these species sense acid strength differently and cause the larger effects of DPE on k{sub mono}. Confinement effects in H-BEA affect the value of k{sub mono} because the different sizes and number of molecules in reactants and transition states selectively stabilize the latter; however, they do not influence k{sub dimer}, for which reactants and transition states of similar size sense spatial constraints to the same extent. This combination of theory and experiment for solid acids of known structure sheds considerable light on the relative contributions from solvation, electrostatic and van der Waals interactions in stabilizing cationic transition states and provides predictive insights into the relative contributions of parallel routes based on the size and charge distributions of their relevant intermediates and transition states. These findings also demonstrate how the consequences of acid strength on measured turnover rates depend on reaction conditions and their concomitant changes in the chemical significance of the rate parameters measured. Moreover, the complementary use of experiment and theory in resolving mechanistic controversies has given predictive guidance about how rate and equilibrium constants, often inextricably combined as measured rate parameters, individually depend on acid strength based on the magnitude and spatial distributions of charges in reactants, products and transition states involved in relevant elementary steps. The unique relations between k{sub mono}, k{sub dimer} and DPE developed here for CH{sub 3}OH dehydration can be applied in practice to assess the acid strength of any solid acid, many of which have unknown structures, preventing reliable calculations of their DPE by theory.

Carr, Robert T.; Neurock, Matthew; Iglesia, Enrique

2011-02-14

128

Catalytic consequences of acid strength in the conversion of methanol to dimethyl ether  

E-print Network

: Polyoxometalate Keggin Dehydration Methanol conversion Density functional theory Acid strength Deprotonation energies, combined with rate data on Keggin polyoxometalate (POM) clusters and zeolite H-BEA. Measured

Iglesia, Enrique

129

Thermodynamic Properties of Dimethyl Carbonatea)  

NASA Astrophysics Data System (ADS)

A thermodynamic property formulation for dimethyl carbonate has been developed with the use of available experimental thermodynamic property data. The equation of state was developed with multiproperty fitting methods involving pressure-density-temperature (p?T), heat capacity, vapor pressure, and saturated-liquid density data. The equation of state conforms to the Maxwell criterion for two-phase liquid-vapor equilibrium states, and is valid for temperatures from the triple-point temperature (277.06 ± 0.63) K to 600 K, for pressures up to 60 MPa, and for densities up to 12.12 mol dm-3. The extrapolation behavior of the equation of state at low and high temperatures and pressures is reasonable. The uncertainties (k = 2, indicating a 95% confidence level) of the equation of state in density are 0.05% for saturated-liquid states below 350 K, rising to 0.1% in the single phase between 278 K and 400 K at pressures up to 60 MPa. Due to the lack of reliable data outside this region, the estimated uncertainties increase to 0.5% to 1% in the vapor and critical regions. The uncertainties in vapor pressure are 0.6% from 310 K to 400 K, and increase to 1% at higher temperatures and to 2% at lower temperatures due to a lack of experimental data. The uncertainty in isobaric heat capacity and speed of sound in the liquid phase at saturation or atmospheric pressure is 0.5% from 280 K to 335 K. The uncertainties are higher for all properties in the critical region. Detailed comparisons between experimental and calculated data, and an analysis of the equation, have been performed.

Zhou, Yong; Wu, Jiangtao; Lemmon, Eric W.

2011-12-01

130

Measuring exposures to glycol ethers.  

PubMed Central

In 1981, NIOSH began investigating the potential reproductive health effects resulting from exposures to a class of organic solvents known generically as glycol ethers (GE). This research was begun as a result of the NIOSH criteria document development program which revealed little data available on the health effects of glycol ether exposure. Toxicologic research was begun by NIOSH and other researchers which suggested substantial reproductive effects in animals. These animal data motivated a study of human exposures in the occupational setting. In 1981 and 1982 NIOSH conducted several walk-through surveys which included preliminary measurements of exposures in a variety of industries including painting trades, coal mining, production blending and distribution facilities, aircraft fueling, and communications equipment repair facilities. The human exposure data from these surveys is summarized in this paper with most results well below 1 parts per million (ppm) and only a few values approaching 10 ppm. Blood samples were collected at one site resulting in GE concentrations below the limit of detection. Exposures to airborne glycol ethers, in the industries investigated during the collection of this data, revealed several problems in reliably sampling GE at low concentrations. It became apparent, from the data and observations of work practices, that air monitoring alone provided an inadequate index of GE exposure. Further field studies of exposure to GE are anticipated, pending location of additional groups of exposed workers and development of more reliable methods for characterizing exposure, especially biological monitoring. PMID:6499824

Clapp, D E; Zaebst, D D; Herrick, R F

1984-01-01

131

Measuring the Aerosol Characteristics of the Optimum Insecticide Spray  

Microsoft Academic Search

Spray characteristics were investigated to determine the optimum aerosol spray for insecticides while considering volatile organic carbon (VOC) reduction. Our ultimate goal is to improve the efficiency of killing insects while using less aerosol spray, which contains chemicals, oil, and dimethyl ether (DME). The chemical content of the aerosol is greatly reduced in the attachment region 1-2 m from the

Yuji Ikeda; Atsushi Nishiyama; Seung Mo Kim; Yoshihiro Horibe; Shigeki Takaki

132

Bio-syngas production from biomass catalytic gasification  

Microsoft Academic Search

A promising application for biomass is liquid fuel synthesis, such as methanol or dimethyl ether (DME). Previous studies have studied syngas production from biomass-derived char, oil and gas. This study intends to explore the technology of syngas production from direct biomass gasification, which may be more economically viable. The ratio of H2\\/CO is an important factor that affects the performance

Pengmei Lv; Zhenhong Yuan; Chuangzhi Wu; Longlong Ma; Yong Chen; Noritatsu Tsubaki

2007-01-01

133

Aza crown ether compounds as anion receptors  

DOEpatents

A family of aza-ether based compounds including linear, multi-branched and aza-crown ethers is provided. When added to non-aqueous battery electrolytes, the new family of aza-ether based compounds acts as neutral receptors to complex the anion moiety of the electrolyte salt thereby increasing the conductivity and the transference number of LI{sup +} ion in alkali metal batteries. 3 figs.

Lee, H.S.; Yang, X.O.; McBreen, J.

1998-08-04

134

Aza crown ether compounds as anion receptors  

DOEpatents

A family of aza-ether based compounds including linear, multi-branched and aza-crown ethers is provided. When added to non-aqueous battery electrolytes, the new family of aza-ether based compounds acts as neutral receptors to complex the anion moiety of the electrolyte salt thereby increasing the conductivity and the transference number of LI.sup.+ ion in alkali metal batteries.

Lee, Hung Sui (East Setauket, NY); Yang, Xiao-Oing (Port Jefferson Station, NY); McBreen, James (Bellport, NY)

1998-08-04

135

Some Complexation Reactions of Cellulosic Ethers  

Microsoft Academic Search

Cellulose ethers were prepared by the reaction of sodium cellulosate with 1-chloromethylnaphthalene, 2-bromomethyl-pyridine, 2-chloropyridine, crotyl bromide, propargyl chloride, and 1-naphthyl glycidyl ether and their complexation ability was investigated. No ?-complex formation with picric acid or 2,4,6-trinitrobenzene took place. Results were attributed to steric hindrance from the cellulosic backbone. Complexation of some metal salts by the crotyl and propargyl ethers was

Yair Avny; Ron Rahman; Albert Zilkha

1972-01-01

136

Crystalline Imide/Arylene Ether Copolymers  

NASA Technical Reports Server (NTRS)

Series of imide/arylene ether block copolymers prepared by using arylene ether blocks to impart low melt viscosity, and imide blocks to provide high strength and other desirable mechanical properties. Work represents extension of LAR-14159 on imide/arylene ether copolymers in form of films, moldings, adhesives, and composite matrices. Copolymers potentially useful in variety of high-temperature aerospace and microelectronic applications.

Jensen, Brian J.; Hergenrother, Paul M.; Bass, Robert G.

1991-01-01

137

40 CFR 721.4133 - Dimethyl-3-substituted heteromonocyclic amine.  

Code of Federal Regulations, 2010 CFR

40 Protection of Environment 30...Dimethyl-3-substituted heteromonocyclic amine. 721.4133 Section 721.4133 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED...Dimethyl-3-substituted heteromonocyclic amine. (a)...

2010-07-01

138

Latitudinal Fractionation of Polybrominated Diphenyl Ethers and  

E-print Network

The flame retardant polybrominated diphenyl ethers (PBDEs) have become ubiquitous environmental pollutants been widely used as flame retardants, coolants, and lubricants in electrical equipment. The total world

Merilä, Juha

139

40 CFR 721.10067 - Ether amine phosphonate salt (generic).  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Ether amine phosphonate salt (generic). 721.10067 Section 721...721.10067 Ether amine phosphonate salt (generic). (a) Chemical substances...identified generically as ether amine phosphonate salt (PMNs P-05-57,...

2013-07-01

140

40 CFR 721.10067 - Ether amine phosphonate salt (generic).  

Code of Federal Regulations, 2012 CFR

...2012-07-01 false Ether amine phosphonate salt (generic). 721.10067 Section 721...721.10067 Ether amine phosphonate salt (generic). (a) Chemical substances...identified generically as ether amine phosphonate salt (PMNs P-05-57,...

2012-07-01

141

40 CFR 721.10067 - Ether amine phosphonate salt (generic).  

Code of Federal Regulations, 2010 CFR

...2010-07-01 false Ether amine phosphonate salt (generic). 721.10067 Section 721...721.10067 Ether amine phosphonate salt (generic). (a) Chemical substances...identified generically as ether amine phosphonate salt (PMNs P-05-57,...

2010-07-01

142

Pulmonary excretion of hydrogen sulfide, methanethiol, dimethyl sulfide and dimethyl disulfide in mice.  

PubMed

Neither hydrogen sulfide nor any other volatile sulfur metabolites were found in the expired breath of mice given sodium sulfide intraperitoneally in doses up to the LD50. The detection system was sensitive to less than 0.1% of the sulfur in the given dose. The intraperitoneal administration of dimethyl disulfide resulted in its appearance in the expired breath of mice as well as much smaller amounts of both methanethiol and dimethyl sulfide. The intraperitoneal administration of methanethiol resulted in its pulmonary excretion as well as that of dimethyl sulfide. Administration of dimethyl sulfide led to its appearance alone in expired breath. Mice pretreated with ammonium acetate and then injected with dimethyl disulfide excreted the same three compounds via the lungs as above, but there were complex changes in the proportions and in the time sequence of their appearance. The absolute amounts of all three were increased, and the peak excretion for each was delayed. The amount excreted as dimethyl sulfide was particularly increased. PMID:755673

Susman, J L; Hornig, J F; Thomae, S C; Smith, R P

1978-01-01

143

Juvenile hormone: activity of aromatic terpenoid ethers.  

PubMed

Several aromatic terpenoid ethers possess a high degree of morpho-genetic activity when assayed on the yellow mealworm Tenebrio molitor L. and the milkweed bug Oncopeltus fasciatus (Dallas). The most active compounds were the 3,4-methylenedioxy-phenyl ethers of 6,7-epoxygeraniol and the corresponding ethyl-branched homologs. PMID:5776643

Bowers, E S

1969-04-18

144

Interaction of low-energy electrons with dimethyl sulfide and dimethyl disulfide  

NASA Astrophysics Data System (ADS)

We report elastic integral cross sections for low-energy electron scattering by gas-phase dimethyl sulfide and dimethyl disulfide, obtained with the Schwinger multichannel method with pseudopotentials. Our symmetry-resolved cross sections for dimethyl sulfide reveal that the single broad structure at 3.25 eV observed in the electron transmission spectrum (assigned as a ?CS* shape resonance) would actually arise from two superimposed anion states in the B2 and A1 symmetry components of the C2 v point group. We also obtained two low-lying shape resonances for dimethyl disulfide, in good agreement with the available electron transmission data. In view of the recently reported measurements on dissociative electron attachment to dimethyl disulfide [C. Matias, A. Mauracher, P. Scheier, P. Limão-Vieira, and S. Denifl, Chem. Phys. Lett. 605-606, 71 (2014), 10.1016/j.cplett.2014.05.016], we also calculated cross sections for stretched S-S bond lengths, which indicate a fast stabilization consistent with the experimental data.

Santos, J. S. dos; Kossoski, F.; Varella, M. T. do N.

2014-11-01

145

Ether polar lipids of methanogenic bacteria: structures, comparative aspects, and biosyntheses.  

PubMed Central

Complete structures of nearly 40 ether polar lipids from seven species of methanogens have been elucidated during the past 10 years. Three kinds of variations of core lipids, macrocyclic archaeol and two hydroxyarchaeols, were identified, in addition to the usual archaeol and caldarchaeol (for the nomenclature of archaeal [archaebacterial] ether lipids, see the text). Polar head groups of methanogen phospholipids include ethanolamine, serine, inositol, N-acetylglucosamine, dimethyl- and trimethylaminopentanetetrol, and glucosaminylinositol. Glucose is the sole hexose moiety of glycolipids in most methanogens, and galactose and mannose have been found in a few species. Methanogen lipids are characterized by their diversity in phosphate-containing polar head groups and core lipids, which in turn can be used for chemotaxonomy of methanogens. This was shown by preliminary simplified analyses of lipid component residues. Core lipid analysis by high-pressure liquid chromatography provides a method of determining the methanogenic biomass in natural samples. There has been significant progress in the biosynthetic studies of methanogen lipids in recent years. In vivo incorporation experiments have led to delineation of the outline of the synthetic route of the diphytanylglycerol ether core. The mechanisms of biosynthesis of tetraether lipids and various polar lipids, and cell-free systems of either lipid synthesis, however, remain to be elucidated. The significance and the origin of archaeal ether lipids is discussed in terms of the lipid composition of bacteria living in a wide variety of environments, the oxygen requirement for biosynthesis of hydrocarbon chains, and the physicochemical properties and functions of lipids as membrane constituents. PMID:8464404

Koga, Y; Nishihara, M; Morii, H; Akagawa-Matsushita, M

1993-01-01

146

Methods for synthesis of nonabromodiphenyl ethers and a chloro-nonabromodiphenyl ether  

Microsoft Academic Search

Polybrominated diphenyl ethers (PBDEs) have been used extensively as brominated flame retardants (BFRs) in textiles, upholstery and electronics. They are ubiquitous contaminants in wildlife and humans. A low concentration of nonabrominated diphenyl ethers (nonaBDEs) is present in commercial DecaBDE and they are also abiotic and biotic debromination products of decabromodiphenyl ether (BDE-209). The objective of the present work was to

Anna Christiansson; Daniel Teclechiel; Johan Eriksson; Åke Bergman; Göran Marsh

2006-01-01

147

A transferable force field to predict phase equilibria and surface tension of ethers and glycol ethers.  

PubMed

We propose a new transferable force field to simulate phase equilibrium and interfacial properties of systems involving ethers and glycol ethers. On the basis of the anisotropic united-atom force field, only one new group is introduced: the ether oxygen atom. The optimized Lennard-Jones (LJ) parameters of this atom are identical whatever the molecule simulated (linear ether, branched ether, cyclic ether, aromatic ether, diether, or glycol ether). Accurate predictions are achieved for pure compound saturated properties, critical properties, and surface tensions of the liquid-vapor interface, as well as for pressure-composition binary mixture diagrams. Multifunctional molecules (1,2-dimethoxyethane, 2-methoxyethanol, diethylene glycol) have also been studied using a recently proposed methodology for the calculation of the intramolecular electrostatic energy avoiding the use of additional empirical parameters. This new force field appears transferable for a wide variety of molecules and properties. It is furthermore worth noticing that binary mixtures have been simulated without introducing empirical binary parameters, highlighting also the transferability to mixtures. Hence, this new force field gives future opportunities to simulate complex systems of industrial interest involving molecules with ether functions. PMID:21800821

Ferrando, Nicolas; Lachet, Véronique; Pérez-Pellitero, Javier; Mackie, Allan D; Malfreyt, Patrice; Boutin, Anne

2011-09-15

148

Survey of the BY Draconis syndrome among dMe stars. [BVr photometry search for slow quasisinusoidal light variations  

NASA Technical Reports Server (NTRS)

Results are reported for a BVr photometric survey of 22 dK, dKe, dM, and dMe stars conducted to search for slow quasi-sinusoidal fluctuations in V (the BY Draconis syndrome). The (B-V) and (V-r) color indices are determined in an attempt to detect wavelength-dependent color changes produced by starspots and to infer starspot temperatures. It is found that nine of the stars exhibit variations in V of the order of 0.05 to 0.10 magnitude on a time scale of days or weeks, that at least three more display changes in mean light level over a period of years, that the stars generally tend to become redder at minimum light, and that some of the stars show no detectable color changes over their photometric cycle. The color data are taken to suggest a probable temperature difference of about 200 to 500 K between the stellar photospheres and starspots if the V variations are attributed to dark spots. It is concluded that the BY Draconis syndrome is clearly a very common occurrence among dMe stars.

Bopp, B. W.; Espenak, F.

1977-01-01

149

27 CFR 21.108 - Ethyl ether.  

Code of Federal Regulations, 2010 CFR

...FORMULAS FOR DENATURED ALCOHOL AND RUM Specifications for Denaturants § 21.108 Ethyl ether. (a) Odor. Characteristic odor. (b) Specific gravity at 15.56 °/15.56 °C. Not more than 0.728. [T.D. ATF-133,...

2010-04-01

150

Phenylethynl-terminated poly(arylene ethers)  

NASA Technical Reports Server (NTRS)

Phenylethynyl-terminated poly(arylene ethers) are prepared in a wide range of molecular weights by adjusting monomer ratio and adding an appropriate amount of 4-fluoro- 4'-phenylethynyl benzophenone during polymer synthesis. The resulting phenylethynyl-terminated poly(arylene ethers) react and crosslink upon curing for one hour at 350 C to provide materials with improved solvent resistance, higher modulus, and better high temperature properties than the linear, uncrosslinked polymers.

Jensen, Brian J. (inventor); Bryant, Robert G. (inventor); Hergenrother, Paul M. (inventor)

1993-01-01

151

Imide/arylene ether copolymers. I  

NASA Technical Reports Server (NTRS)

The preparation of a series of novel imide/arylene ether copolymers is described together with the results of viscosity and DSC Tg(Tm) measurements. The copolymers were synthesized from an arylene ether block and either an amorphous or semicrystalline imide block. One block copolymer was end-capped, and the molecular weight was controlled to improve compression moldability. The paper also presents results of mechanical properties tests on copolymer samples.

Jensen, B. J.; Hergenrother, P. M.; Bass, R. G.

1991-01-01

152

Synthesis and Characterization of Poly(phthalazinone Ether Nitrile) Copolymers with Hydrophobic Surface  

NASA Astrophysics Data System (ADS)

Poly(phthalazinone ether nitrile) (PPEN) block copolymers containing polysiloxane were prepared so as to create a strongly hydrophobic polymer surface. The copolymers were synthesized from eugenol end-capped polydimethylsiloxane (PDMS) and fluoro-terminated PPEN oligomers by the aromatic nucleophilic substitution polycondensation in the presence of dimethyl sulfoxide/o-dichlorobenzene and K2CO3 as solvents and catalyst, respectively. The resultant copolymers were characterized by FTIR, 1H NMR, and gel permeation chromatography. XPS analysis results indicated that the copolymer film had a very rich PDMS segment surface. Atomic force microscopy further showed that there existed a continuous PDMS phase on the copolymer surface and PPEN as the dispersive particles was dispersed at diameters between 0.1 and 0.3 nm. The enrichment of PDMS in the copolymer surface could be responsible for an increase of surface water repellency (113.4°).

Dong, L. M.; Liao, G. X.; Liu, C.; Yang, S. S.; Jian, X. G.

153

40 CFR 721.10100 - Dialkyl dimethyl ammonium carbonate (2:1) (generic).  

Code of Federal Regulations, 2010 CFR

...2010-07-01 false Dialkyl dimethyl ammonium carbonate (2:1) (generic). 721...Substances § 721.10100 Dialkyl dimethyl ammonium carbonate (2:1) (generic). ...identified generically as dialkyl dimethyl ammonium carbonate (2:1) (PMN...

2010-07-01

154

40 CFR 721.10666 - Quaternary ammonium compounds, bis(fattyalkyl) dimethyl, salts with tannins (generic).  

Code of Federal Regulations, 2013 CFR

...bis(fattyalkyl) dimethyl, salts with tannins (generic). 721.10666 Section...bis(fattyalkyl) dimethyl, salts with tannins (generic). (a) Chemical substance...bis(fattyalkyl) dimethyl, salts with tannins (PMN P-12-437) is subject to...

2013-07-01

155

40 CFR 721.10666 - Quaternary ammonium compounds, bis(fattyalkyl) dimethyl, salts with tannins (generic).  

Code of Federal Regulations, 2014 CFR

...bis(fattyalkyl) dimethyl, salts with tannins (generic). 721.10666 Section...bis(fattyalkyl) dimethyl, salts with tannins (generic). (a) Chemical substance...bis(fattyalkyl) dimethyl, salts with tannins (PMN P-12-437) is subject to...

2014-07-01

156

Revisiting optical clearing with dimethyl sulfoxide (DMSO)  

PubMed Central

Functional optical characterization of disease progression and response to therapy suffers from loss of spatial resolution and imaging depth due to scattering. Here we report on the ability of dimethyl sulfoxide (DMSO) alone to reduce the optical scattering of skin. We observed a three-fold reduction in the scattering of skin with topical DMSO application. With an in vivo window chamber model, we observed a three-fold increase in light transmittance through the preparation and enhanced visualization of subsurface microvasculature. Collectively, our data demonstrate the potential of DMSO alone to mitigate effects of scattering, which we expect will improve molecular imaging studies. PMID:19226579

Bui, Albert K.; McClure, R. Anthony; Chang, Jennell; Stoianovici, Charles; Hirshburg, Jason; Yeh, Alvin T.; Choi, Bernard

2009-01-01

157

21 CFR 524.660 - Dimethyl sulfoxide ophthalmic and topical dosage forms.  

Code of Federal Regulations, 2010 CFR

...Dimethyl sulfoxide ophthalmic and topical dosage forms. 524.660 Section...RELATED PRODUCTS OPHTHALMIC AND TOPICAL DOSAGE FORM NEW ANIMAL DRUGS ...Dimethyl sulfoxide ophthalmic and topical dosage...

2010-04-01

158

21 CFR 524.660 - Dimethyl sulfoxide ophthalmic and topical dosage forms.  

Code of Federal Regulations, 2013 CFR

...Dimethyl sulfoxide ophthalmic and topical dosage forms. 524.660 Section...RELATED PRODUCTS OPHTHALMIC AND TOPICAL DOSAGE FORM NEW ANIMAL DRUGS ...Dimethyl sulfoxide ophthalmic and topical dosage...

2013-04-01

159

21 CFR 524.660 - Dimethyl sulfoxide ophthalmic and topical dosage forms.  

Code of Federal Regulations, 2012 CFR

...Dimethyl sulfoxide ophthalmic and topical dosage forms. 524.660 Section...RELATED PRODUCTS OPHTHALMIC AND TOPICAL DOSAGE FORM NEW ANIMAL DRUGS ...Dimethyl sulfoxide ophthalmic and topical dosage...

2012-04-01

160

21 CFR 524.660 - Dimethyl sulfoxide ophthalmic and topical dosage forms.  

Code of Federal Regulations, 2011 CFR

...Dimethyl sulfoxide ophthalmic and topical dosage forms. 524.660 Section...RELATED PRODUCTS OPHTHALMIC AND TOPICAL DOSAGE FORM NEW ANIMAL DRUGS ...Dimethyl sulfoxide ophthalmic and topical dosage...

2011-04-01

161

Preparation and characterization of new low melting ammonium-based ionic liquids with ether functionality  

NASA Astrophysics Data System (ADS)

Eighteen new and three previously known but insufficiently characterized R? 3N +A - and R 2? 2N +A - type ( R = 2-ethoxyethyl or 4-methoxybenzyl, ? = methyl, ethyl, n-propyl, n-butyl, n-pentyl or n-hexyl, A = Br, BF 4 or PF 6) quaternary ammonium (QA) salts were synthesized and characterized by using 1H and 13C NMR techniques, mass spectroscopy and elemental analysis. The bromide salts were synthesized either by treating dimethyl formamide with an ether functionalized alkyl bromide in the presence of potassium carbonate or by treating a tertiary amine with an ether functionalized alkyl bromide. The QA tetrafluoroborates and hexafluorophosphates were synthesized by metathesis reaction between a prepared QA bromide and HBF 4 or KPF 6. The crystal structures of four compounds were determined by X-ray single crystal diffraction and powder diffraction was used to study the crystallinity of the solid compounds and to compare the structural similarities between the single crystals and the microcrystalline bulk form. Thermal properties of all compounds were studied by using TG/DTA and DSC methods. The anion exchange had a clear lowering effect on the melting points and enhanced the thermal stability of the BF4- and PF6- salts compared to the analogous bromides. Most of the compounds melted clearly below 100 °C, of which four are liquid at room temperature.

Kärnä, Minna; Lahtinen, Manu; Valkonen, Jussi

2009-03-01

162

An Immunoassay for Monitoring Environmental and Human Exposure to the Polybrominated Diphenyl Ether BDE-47  

PubMed Central

We developed a selective competitive enzyme-linked immunosorbent assay (ELISA) to monitor environmental and human exposure to polybrominated diphenyl ether BDE-47 that is used as a flame retardant. 2,2’,4,4’-Tetrabromodiphenyl ether (BDE-47) a dominant PBDE congener of toxicological concern, was the target analyte. To achieve effective hapten presentation on the carrier protein for antibody production, immunizing haptens with a rigid double-bonded hydrocarbon linker introduced at different positions on the target molecule were synthesized as well as coating haptens that mimic a characteristic fragment of the molecule. Rabbit antisera produced against each immunizing antigen were screened against competitive hapten coating antigens. Under optimized competitive indirect ELISA conditions, the linear detection range in the assay buffer that includes 50% dimethyl sulfoxide was 0.35 - 8.50 ?g/L with an IC50 value of 1.75 ?g/L for BDE-47. Little or no cross-reactivity (< 6%) was observed to related PBDE congeners containing the BDE-47 moiety and other halogenated compounds. Using a magnetic particle-based competitive direct ELISA increased the sensitivity by 10-fold over the indirect ELISA. The ELISA provided quantitative results when performed on small volume/weight samples such as dust, furniture foam, and blood/serum following sample preparation, suggesting a convenient screening tool. PMID:19921894

Ahn, Ki Chang; Gee, Shirley J.; Tsai, Hsing-Ju; Bennett, Deborah; Nishioka, Marcia G.; Blum, Arlene; Fishman, Elana; Hammock, Bruce D.

2012-01-01

163

Rigid-strut-containing crown ethers and [2]catenanes for incorporation into metal-organic frameworks.  

PubMed

To introduce crown ethers into the struts of metal-organic frameworks (MOFs), general approaches have been developed for the syntheses of dicarboxylic acid dibenzo[30]crown-10 (DB30C10DA), dicarboxylic acid di-2,3-naphtho[30]crown-10 (DN30C10DA), dicarboxylic acid bisparaphenylene[34]crown-10 (BPP34C10DA), and dicarboxylic acid 1,5-naphthoparaphenylene[36]crown-10 (NPP36C10DA). These novel crown ethers not only retain the characteristics of their parent crown ethers since they can 1) bind cationic guests and 2) serve as templates for making mechanically interlocked molecules (MIMs), such as catenanes and rotaxanes, but they also present coordination sites to connect with secondary building units (SBUs) in MOFs. The binding behavior of BPP34C10DA with 1,1'-dimethyl-4,4'-bipyridinium bis(hexafluorophosphate) (DMBP2.PF(6)) has been investigated by means of UV/Vis, fluorescence, and NMR spectroscopic techniques. The crystal superstructure of the complex DMBP2.PF(6) subset BPP34C10DA was determined by X-ray crystallography. The NPP36C10DA-based [2]catenane (H(2)NPP36C10DC-CAT4.PF(6)) and the BPP34C10DA-based [2]catenane (H(2)BPP34C10DC-CAT4.PF(6)) were prepared in DMF at room temperature by the template-directed clipping reactions of the planarly chiral NPP36C10DA and BPP34C10DA with 1,1'-[1,4-phenylenebis(methylene)]di-4,4'-bipyridin-1-ium bis(hexafluorophosphate) and 1,4-bis(bromomethyl)benzene, respectively. The crystal structure of the dimethyl ester (BPP34C10DE-CAT4.PF(6)) of the [2]catenane H(2)BPP34C10DC-CAT4.PF(6) was investigated by X-ray crystallography, which revealed racemic R and S isomers with planar chirality present in the crystal in a 1:1 ratio. These crown ether based struts serve as excellent organic ligands to bind with transition metal ions in the construction of MOFs: the crown ethers BPP34C10DA and NPP36C10DA in the presence of Zn(NO(3))(2)4.H(2)O afforded the MOF-1001 and MOF-1002 frameworks, respectively. The crystal structures of MOF-1001 and MOF-1002 are both cubic and display Fm3m symmetry. The unit cell parameter of the metal-organic frameworks is a=52.9345 A. Since such MOFs, containing electron-donating crown ethers are capable of docking incoming electron-accepting substrates in a stereoelectronically controlled fashion, the present work opens a new access to the preparation and application of MOFs. PMID:19946906

Zhao, Yan-Li; Liu, Lihua; Zhang, Wenyu; Sue, Chi-Hau; Li, Qiaowei; Miljani?, Ognjen S; Yaghi, Omar M; Stoddart, J Fraser

2009-12-14

164

Extended Fizeau experiment and the ether  

SciTech Connect

In view of the current interest in constructing ether-like models, a simple analysis is given of how the description of the classic Fizeau experiment becomes modified if the moving dielectric is surrounded by a nonviscous fluid, the ether, having dielectric constant N. For analytic tractability we introduce an explicit model in which the change in fluid velocity is slow for an optical wave traveling from the resting ether into the moving medium. We show how the Einstein addition formula for velocities is not modified at all. What is changed, however, is the expression for the wave frequency in the rest inertial frame of the medium. This change is in principle measurable. Worth noticing is the close resemblance between this kind of theory and the covariant electrodynamics for a medium in uniform rectilinear motion. This point is elaborated upon by comparing with the Lorentz-violating electrodynamics studied by Kostelecky and collaborators in several recent papers.

Brevik, Iver [Department of Energy and Process Engineering, Norwegian University of Science and Technology, N-7491 Trondheim (Norway)

2010-11-15

165

37. BUILDING NO. 519, ETHER AND ALCOHOL RECOVERY HOUSE, NORTHWEST ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

37. BUILDING NO. 519, ETHER AND ALCOHOL RECOVERY HOUSE, NORTHWEST CORNER OF BUILDING. BUILDING NO. 521 (ETHER VAULT) IN BACKGROUND LEFT. - Picatinny Arsenal, 500 Area, Powder Factory & Power House, State Route 15 near I-80, Dover, Morris County, NJ

166

41. LOOKING WEST AT BUILDING NO. 519, ETHER AND ALCOHOL ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

41. LOOKING WEST AT BUILDING NO. 519, ETHER AND ALCOHOL RECOVERY HOUSE, (LEFT) AND BUILDING NO. 521, ETHER VAULT, (RIGHT) IN FOREGROUND - Picatinny Arsenal, 500 Area, Powder Factory & Power House, State Route 15 near I-80, Dover, Morris County, NJ

167

40 CFR 721.10069 - Ether amine phosphonate (generic).  

Code of Federal Regulations, 2010 CFR

40 Protection of Environment 30...2010-07-01 false Ether amine phosphonate (generic...Section 721.10069 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED...721.10069 Ether amine phosphonate...

2010-07-01

168

Crystalline imide/arylene ether copolymers  

NASA Technical Reports Server (NTRS)

Crystalline imide/arylene ether block copolymers are prepared by reacting anhydride terminated poly(amic acids) with amine terminated poly)arylene ethers) in polar aprotic solvents and chemically or thermally cyclodehydrating the resulting intermediate poly(amic acids). The block copolymers of the invention have one glass transition temperature or two, depending on the particular structure and/or the compatibility of the block units. Most of these crystalline block copolymers for tough, solvent resistant films with high tensile properties. While all of the copolymers produced by the present invention are crystalline, testing reveals that copolymers with longer imide blocks or higher imide content have increased crystallinity.

Jensen, Brian J. (inventor); Hergenrother, Paul M. (inventor); Bass, Robert G. (inventor)

1995-01-01

169

High octane ethers from synthesis gas-derived alcohols  

SciTech Connect

The objective of the proposed research is to synthesize high octane ethers, primarily methyl isobutyl ether (MIBE) and methyl tertiary butyl ether (MTBE), directly from H{sub 2}/CO/CO{sub 2} coal-derived synthesis gas via alcohol mixtures that are rich in methanol and 2-methyl-1-propanol (isobutanol). The overall scheme involves gasification of coal, purification and shifting of the synthesis gas, higher alcohol synthesis, and direct synthesis of ethers.

Klier, K.; Herman, R.G.; Johansson, M.; Feeley, O.C.

1992-01-01

170

39. BUILDING NO. 519, ETHER AND ALCOHOL RECOVERY HOUSE, LOOKING ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

39. BUILDING NO. 519, ETHER AND ALCOHOL RECOVERY HOUSE, LOOKING AT SOUTHWEST CORNER WITH BUILDING NO. 521, ETHER VAULT, AND BUILDING NO. 519-A, ETHER & ALOCOHL STORAGE TANKS, IN BACKGROUND RIGHT. - Picatinny Arsenal, 500 Area, Powder Factory & Power House, State Route 15 near I-80, Dover, Morris County, NJ

171

40 CFR 721.3435 - Butoxy-substituted ether alkane.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Butoxy-substituted ether alkane. 721.3435 Section 721.3435 ...721.3435 Butoxy-substituted ether alkane. (a) Chemical substance and significant...generically as butoxy-substituted ether alkane (PMN P-92-755) is subject to...

2013-07-01

172

40 CFR 721.3435 - Butoxy-substituted ether alkane.  

Code of Federal Regulations, 2012 CFR

...2012-07-01 false Butoxy-substituted ether alkane. 721.3435 Section 721.3435 ...721.3435 Butoxy-substituted ether alkane. (a) Chemical substance and significant...generically as butoxy-substituted ether alkane (PMN P-92-755) is subject to...

2012-07-01

173

40 CFR 721.3435 - Butoxy-substituted ether alkane.  

Code of Federal Regulations, 2014 CFR

...2014-07-01 false Butoxy-substituted ether alkane. 721.3435 Section 721.3435 ...721.3435 Butoxy-substituted ether alkane. (a) Chemical substance and significant...generically as butoxy-substituted ether alkane (PMN P-92-755) is subject to...

2014-07-01

174

40 CFR 721.3435 - Butoxy-substituted ether alkane.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 false Butoxy-substituted ether alkane. 721.3435 Section 721.3435 ...721.3435 Butoxy-substituted ether alkane. (a) Chemical substance and significant...generically as butoxy-substituted ether alkane (PMN P-92-755) is subject to...

2010-07-01

175

40 CFR 721.3435 - Butoxy-substituted ether alkane.  

Code of Federal Regulations, 2011 CFR

...2011-07-01 false Butoxy-substituted ether alkane. 721.3435 Section 721.3435 ...721.3435 Butoxy-substituted ether alkane. (a) Chemical substance and significant...generically as butoxy-substituted ether alkane (PMN P-92-755) is subject to...

2011-07-01

176

Biomonitoring Polybrominated Diphenyl Ethers in Lactating Women  

Technology Transfer Automated Retrieval System (TEKTRAN)

Breast milk is a valuable biological specimen for biomonitoring lipid-soluble polybrominated diphenyl ethers (PBDEs). The goal of this project was to determine the levels of PBDEs in breast milk of lactating women from the Seacoast region of New Hampshire and to examine potential relationships betw...

177

Polybrominated diphenyl ether (PBDE) flame retardants  

Microsoft Academic Search

Polybrominated diphenyl ether, PBDE, flame retardants are now a world-wide pollution problem reaching even remote areas. They have been found to bioaccumulate and there are concerns over the health effects of exposure to PBDEs, they also have potential endocrine disrupting properties. They are lipophilic compounds so are easily removed from the aqueous environment and are predicted to sorb onto sediments

Frank Rahman; Katherine H Langford; Mark D Scrimshaw; John N Lester

2001-01-01

178

"Crown Ether" Synthesis: An Organic Laboratory Experiment.  

ERIC Educational Resources Information Center

This experiment is designed to acquaint the student with a macromolecular synthesis of a crown ether type compound. The starting materials are readily available and the product, a cyclic polyether, belongs to a class of compounds that has aroused the interest of chemist and biologist alike. (Author/BB)

Field, Kurt W.; And Others

1979-01-01

179

Maternal Anesthesia via Isoflurane or Ether Differentially  

E-print Network

Psychobiol 49: 675­684, 2007. Keywords: isoflurane; ether; behavior; fetal; perinatal; newborn; labor contrac led to appreciable change in our perspective on life before birth. Astounding technological advances behavioral capacities prior to birth (for reviews, see Hopkins & Johnson, 2005; Smotherman & Robinson, 1988

180

Imide/arylene ether block copolymers  

NASA Technical Reports Server (NTRS)

Two series of imide/arylene either block copolymers were prepared using an arylene ether block and either an amorphous or semi-crystalline imide block. The resulting copolymers were characterized and selected physical and mechanical properties were determined. These results, as well as comparisons to the homopolymer properties, are discussed.

Jensen, B. J.; Hergenrother, P. M.; Bass, R. G.

1991-01-01

181

Dimensionally Stable Ether-Containing Polyimide Copolymers  

NASA Technical Reports Server (NTRS)

Novel polyimide copolymers containing ether linkages were prepared by the reaction of an equimolar amount of dianhydride and a combination of diamines. The polyimide copolymers described herein possess the unique features of low moisture uptake, dimensional stability, good mechanical properties, and moderate glass transition temperatures. These materials have potential application as encapsulants and interlayer dielectrics.

Fay, Catharine C. (Inventor); St.Clair, Anne K. (Inventor)

1999-01-01

182

Synthesis and characterization of new poly(arylene ether)s based on dihydroxynaphthalene isomers  

Microsoft Academic Search

A series of new poly(arylene ether ketone)s and poly(arylene ether sulfone)s, obtained starting from dihydroxynaphthalene isomers, have been prepared by solution condensation polymerization. The polymers, having inherent viscosities from 0.20 to 0.77 dl g?1, have been obtained in quantitative yields, had excellent thermal stability as shown by 10% weight loss temperatures in nitrogen and air (above 460 and 430°C, respectively)

F. A. Bottino; G. Di Pasquale; N. Leonardi; A. Pollicino

1998-01-01

183

Living cationic polymerization of vinyl ethers in the presence of iodomethyl methyl ether and zinc iodide  

Microsoft Academic Search

Living cationic polymerization behaviors of isobutyl vinyl ethers (IBVE), initiated by iodomethyl methyl ether (IMME)\\/zinc\\u000a iodide (ZnI2) have been investigated. The polymerization was carried out at 0, ?15, and ?30°C in toluene. It was found that the rate of\\u000a polymerization increased as the IMME concentration increased and decreased as temperature decreased. 100% conversion was always\\u000a achieved without exception. Furthermore, the

Soonhong Kwon; Yunsung Lee; Soukil Mah

2001-01-01

184

All-solid supercapacitor based on polyaniline and sulfonated poly(ether ether ketone)  

Microsoft Academic Search

An all-solid supercapacitor has been fabricated using polyaniline (Pani) and sulfonated poly(ether ether ketone) (SPEEK). A composite electrode is made from chemically-synthesized Pani, SPEEK, electronically conducting carbon black and polytetrafluoroethylene (PTFE). SPEEK acts as both separator and electrolyte. The unit cell consists of two electrodes made from a p dopable Pani composite electrode separated by a SPEEK membrane with a

P. Sivaraman; V. R. Hande; V. S. Mishra; Ch. Srinivasa Rao; A. B. Samui

2003-01-01

185

Low equivalent weight Friedel-Crafts cross-linked sulfonated poly(ether ether ketone)  

Microsoft Academic Search

Poly(ether ether ketone) (PEEK) was sulfonated by electrophillic aromatic substitution to produce a highly water soluble polymer. With an equivalent weight (EW) of 381g\\/eq, the polymer is capable of a proton conductivity of 0.2S\\/cm at 80°C and 100% relative humidity (RH). High proton conductivity in polymer electrolyte membranes is a key factor for optimum hydrogen fuel cell performance. Under testing

Stephen L. N. H. Rhoden; Clovis A. Linkous; Nahid Mohajeri; Diego J. Díaz; Paul Brooker; Darlene K. Slattery; James M. Fenton

2011-01-01

186

Process for making propenyl ethers and photopolymerizable compositions containing them  

DOEpatents

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.

Crivello, James V. (Clifton Park, NY)

1996-01-01

187

Process for making propenyl ethers and photopolymerizable compositions containing them  

DOEpatents

Propenyl ether monomers of formula A(OCH{double_bond}CHCH{sub 3}){sub n} (V) 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.

Crivello, J.V.

1996-01-23

188

IGNITION IMPROVEMENT OF LEAN NATURAL GAS MIXTURES  

SciTech Connect

This report describes work performed during a thirty month project which involves the production of dimethyl ether (DME) on-site for use as an ignition-improving additive in a compression-ignition natural gas engine. A single cylinder spark ignition engine was converted to compression ignition operation. The engine was then fully instrumented with a cylinder pressure transducer, crank shaft position sensor, airflow meter, natural gas mass flow sensor, and an exhaust temperature sensor. Finally, the engine was interfaced with a control system for pilot injection of DME. The engine testing is currently in progress. In addition, a one-pass process to form DME from natural gas was simulated with chemical processing software. Natural gas is reformed to synthesis gas (a mixture of hydrogen and carbon monoxide), converted into methanol, and finally to DME in three steps. Of additional benefit to the internal combustion engine, the offgas from the pilot process can be mixed with the main natural gas charge and is expected to improve engine performance. Furthermore, a one-pass pilot facility was constructed to produce 3.7 liters/hour (0.98 gallons/hour) DME from methanol in order to characterize the effluent DME solution and determine suitability for engine use. Successful production of DME led to an economic estimate of completing a full natural gas-to-DME pilot process. Additional experimental work in constructing a synthesis gas to methanol reactor is in progress. The overall recommendation from this work is that natural gas to DME is not a suitable pathway to improved natural gas engine performance. The major reasons are difficulties in handling DME for pilot injection and the large capital costs associated with DME production from natural gas.

Jason M. Keith

2005-02-01

189

Certain glycol ethers eliminated from toxic chemical release reporting requirements  

SciTech Connect

Effective June 28, 1994, the U.S. Environmental Protection Agency (EPA) eliminated high molecular weight glycol ethers from the reporting requirements of section 313 of the Emergency Planning and Community Right-To-Know Act of 1986 (EPCRA). EPCRA (42 U.S.C. 11023) is also referred to as Title III of the Superfund Amendments and Reauthorization Act (SARA) of 1986. EPA redefined the glycol ethers category list of chemicals subject to reporting based on an EPA review of available human health data on short-chain glycol ethers. EPA is removing only the surfactant glycol ethers, which are high molecular weight glycol ethers, i.e., those with pendant alkyl groups and that typically have eight or more carbon atoms. The redefinition retains certain glycol ethers (i.e., ethylene glycol ethers where there are 1,2, or 3 repeating ethylene oxide groups) in the category. These are reasonably anticipated to cause adverse human health effects.

NONE

1994-09-01

190

OXIDATION OF METHYL FLUORIDE AND DIMETHYL ETHER BY AMMONIA MONOOXYGENASE IN NITROSOMONAS EUROPAEA. (R825689C009)  

EPA Science Inventory

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...

191

Synthesis and utility of fluorogenic acetoxymethyl ethers.  

PubMed

Phenolic fluorophores such as fluorescein, Tokyo Green, resorufin, and their derivatives are workhorses of biological science. Acylating the phenolic hydroxyl group(s) in these fluorophores masks their fluorescence. The ensuing ester is a substrate for cellular esterases, which can restore fluorescence. These esters are, however, notoriously unstable to hydrolysis, severely compromising their utility. The acetoxymethyl (AM) group is an esterase-sensitive motif that can mask polar functionalities in small molecules. Here, we report on the use of AM ether groups to mask phenolic fluorophores. The resulting profluorophores have a desirable combination of low background fluorescence, high chemical stability, and high enzymatic reactivity, both in vitro and in cellulo. These simple phenyl ether-based profluorophores could supplement or supplant the use of phenyl esters for imaging biochemical and biological systems. PMID:21394227

Lavis, Luke D; Chao, Tzu-Yuan; Raines, Ronald T

2011-01-01

192

Synthesis and utility of fluorogenic acetoxymethyl ethers  

PubMed Central

Phenolic fluorophores such as fluorescein, Tokyo Green, resorufin, and their derivatives are workhorses of biological science. Acylating the phenolic hydroxyl group(s) in these fluorophores masks their fluorescence. The ensuing ester is a substrate for cellular esterases, which can restore fluorescence. These esters are, however, notoriously unstable to hydrolysis, severely compromising their utility. The acetoxymethyl (AM) group is an esterase-sensitive motif that can mask polar functionalities in small molecules. Here, we report on the use of AM ether groups to mask phenolic fluorophores. The resulting profluorophores have a desirable combination of low background fluorescence, high chemical stability, and high enzymatic reactivity, both in vitro and in cellulo. These simple phenyl ether-based profluorophores could supplement or supplant the use of phenyl esters for imaging biochemical and biological systems. PMID:21394227

Lavis, Luke D.; Chao, Tzu-Yuan

2011-01-01

193

Emergent gravity and ether-drift experiments  

E-print Network

In principle, ether-drift experiments could distinguish phenomenologically emergent-gravity approaches, where an effective curvature emerges from hydrodynamic distortions of the same physical, flat-space vacuum, from the more conventional scenario where curvature is considered a fundamental property of space-time down to extremely small length scales and the speed of light represents a universal constant. From an experimental point of view, in this particular context, besides time modulations that might be induced by the Earth's rotation (and its orbital revolution), one should also consider the possibility of random fluctuations of the signal. These might reflect the stochastic nature of the underlying 'quantum ether' and be erroneously interpreted as mere instrumental noise. To test the present interpretation, we have extracted the mean amplitude of the signal from various experiments with different systematics, operating both at room temperature and in the cryogenic regime. They all give the same consisten...

Consoli, M

2009-01-01

194

Ether bridge formation in loline alkaloid biosynthesis  

PubMed Central

Lolines are potent insecticidal agents produced by endophytic fungi of cool-season grasses. These alkaloids are composed of a pyrrolizidine ring system and an uncommon ether bridge linking carbons 2 and 7. Previous results indicated that 1-aminopyrrolizidine was a pathway intermediate. We used RNA interference to knock down expression of lolO, resulting in the accumulation of a novel alkaloid identified as exo-1-acetamidopyrrolizidine based on high-resolution MS and NMR. Genomes of endophytes differing in alkaloid profiles were sequenced, revealing that those with mutated lolO accumulated exo-1-acetamidopyrrolizidine but no lolines. Heterologous expression of wild-type lolO complemented a lolO mutant, resulting in the production of N-acetylnorloline. These results indicated that the non-heme iron oxygenase, LolO, is required for ether bridge formation, probably through oxidation of exo-1-acetamidopyrrolizidine. PMID:24374065

Pan, Juan; Bhardwaj, Minakshi; Faulkner, Jerome R.; Nagabhyru, Padmaja; Charlton, Nikki D.; Higashi, Richard M.; Miller, Anne-Frances; Young, Carolyn A.; Grossman, Robert B.; Schardl, Christopher L.

2014-01-01

195

Promoting environmentally sound management of polybrominated diphenyl ethers in Asia.  

PubMed

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 sound management of polybrominated diphenyl ethers in Asia. PMID:24846783

Li, Jinhui; Zhao, Nana; Liu, Xue; Wu, Xiaoyang

2014-05-20

196

Solvent effect on the complex formation of a crown ether derivative with sodium and potassium ions. Thermodynamic background of selectivity  

NASA Astrophysics Data System (ADS)

The complexation properties of dimethyl-pyridino-18-crown-6 ether (M2P18C6) with Na+ and K+ in different primary alcohols including methanol (MeOH), ethanol (EtOH) and n-propanol (n-PrOH) were investigated by UV-vis spectroscopy. Stability constants and thermodynamic parameters have been determined applying the van't Hoff theory. In the cases of both Na+ and K+ the stability constants increase with decreasing permittivity of the solvent used. M2P18C6 always exhibits better affinity to K+ in each alcoholic solution compared to Na+. Thermodynamic studies suggest that in both cases there is a correlation between the permittivity of the solvent and the enthalpy and entropy change of complex formation.

Li, Yin; Huszthy, Péter; Móczár, Ildikó; Szemenyei, Balázs; Kunsági-Máté, Sándor

2013-01-01

197

Dimethyl disulfide (DMDS) and dimethyl sulfide (DMS) emissions from biomass burning in Australia  

NASA Astrophysics Data System (ADS)

We identify dimethyl disulfide (DMDS) as the major reduced sulfur-containing gas emitted from bushfires in Australia's Northern Territory. Like dimethyl sulfide (DMS), DMDS is oxidized in the atmosphere to sulfur dioxide (SO2) and methane sulfonic acid (MSA), which are intermediates in the formation of sulfuric acid (H2SO4). The mixing ratios of DMDS and DMS were the highest we have ever detected, with maximum values of 113 and 35 ppbv, respectively, whereas background values were below the detection limit (10 pptv). Molar emission ratios relative to carbon monoxide (CO) were [1.6 +/- 0.1] × 10-5 and [6.2 +/- 0.3] × 10-6, for DMDS and DMS respectively, while molar emission ratios relative to carbon dioxide (CO2) were [4.7 +/- 0.4] × 10-6 and [1.4 +/- 0.4] × 10-7, respectively. Assuming these observations are representative of biomass burning, we estimate that biomass burning could yield up to 175 Gg/yr of DMDS (119 Gg S/yr) and 13 Gg/yr of DMS.

Meinardi, Simone; Simpson, Isobel J.; Blake, Nicola J.; Blake, Donald R.; Rowland, F. Sherwood

2003-05-01

198

Oxidation of Dimethyl Sulfide to Dimethyl Sulfoxide by Phototrophic Purple Bacteria  

PubMed Central

Enrichment cultures of phototrophic purple bacteria rapidly oxidized up to 10 mM dimethyl sulfide (DMS) to dimethyl sulfoxide (DMSO). DMSO was qualitatively identified by proton nuclear magnetic resonance. By using a biological assay, DMSO was always quantitatively recovered from the culture media. DMS oxidation was not detected in cultures incubated in the dark, and it was slow in cultures exposed to full daylight. Under optimal conditions, the second-order rate constant for DMS oxidation was 6 day?1 mg of protein?1 ml?1. The rate constant was reduced in the presence of high concentration of sulfide (>1 mM), but was not affected by the addition of acetate. DMS was also oxidized to DMSO by a pure strain (tentatively identified as a Thiocystis sp.) isolated from the enrichment cultures. DMS supported growth of the enrichment cultures and of the pure strain by serving as an electron source for photosynthesis. A determination of the amount of protein produced in the cultures and an estimation of the electron balance suggested that the two electrons liberated during the oxidation of DMS to DMSO were quantitatively used to reduce carbon dioxide to biomass. The oxidation of DMS by phototrophic purple bacteria may be an important source of DMSO detected in anaerobic ponds and marshes. PMID:16347425

Zeyer, Josef; Eicher, Petra; Wakeham, Stuart G.; Schwarzenbach, René P.

1987-01-01

199

Removal of H{sub 2}S, methyl macapton dimethyl sulfide and dimethyl disulfide with biofiltration  

SciTech Connect

A pilot study describes the biofiltration process control that was necessary to remove H{sub 2}S, methyl mercaptan, dimethyl sulfide, and dimethyl disulfide, when mixed in an airstream. A pilot test at a waste water treatment facility was operated over a six month period. During that time H{sub 2}S was removed with very high efficiency at concentrations that reached to 400 ppm{sub v}; H{sub 2}S loading reached as high as 20 gms/m{sup 3}/hr. Methyl mercaptan and the organic sulfides were not removed sufficiently to deodorize the air-stream until a second stage biofilter was added. An odor analysis indicated that the odor detection level was approximately 250,000 odor units at the inlet and 1100 odor units at the outlet. The sulfur distribution in the media indicated that elemental sulfur and sulfate is deposited as a byproduct of the H{sub 2}S oxidation. Data from a fall scale biofilter treating H{sub 2}S from a pumping station is also presented. This data shows very efficient removal of H{sub 2}S, no organic reduced sulfur compounds were found in this air-stream.

Singleton, B.; Milligan, D.

1996-12-31

200

From ether theory to ether theology: Oliver Lodge and the physics of immortality.  

PubMed

This article follows the development of physicist Oliver Lodge's religio-scientific worldview, beginning with his reticent attraction to metaphysics in the early 1880s to the full formulation of his "ether theology" in the late 1890s. Lodge undertook the study of psychical phenomena such as telepathy, telekinesis, and "ectoplasm" to further his scientific investigations of the ether, speculating that electrical and psychical manifestations were linked phenomena that described the deeper underlying structures of the universe, beneath and beyond matter. For Lodge, to fully understand the ether was to force from the universe an ultimate Revelation, and psychical research, as the most modern and probatory science, was poised to replace religion as the means of that disclosure. PMID:17205538

Raia, Courtenay Grean

2007-01-01

201

Solubility behavior of ethyl cellulose in supercritical fluid solvents  

Microsoft Academic Search

Solubility data to 180°C and 1200 bar are reported for ?1.0 wt.% ethyl cellulose (50% ethoxyl content, 2.5 average degree of substitution) (EC) in neat supercritical fluid (SCF) chlorodifluoromethane (F22); difluoromethane; 1-chloro-1,1-difluoroethane; 1,1-difluoroethane; and dimethyl ether (DME). The pressures needed to dissolve EC in the polar fluorocarbons decreases with increasing solvent size. The exception in this trend is F22 which

Dan Li; Mark A. McHugh

2004-01-01

202

Alternative biofuels  

Microsoft Academic Search

This study presents the experimental results for the dimethyl ether (DME) + propane system obtained using the Burnett method.\\u000a The apparatus was calibrated using helium. PVTx measurements were taken for four isotherms (344, 354, 364, and 375 K), performing 16 Burnett expansions in pressures ranging\\u000a from about 3,000 to 70 kPa. The second and third virial coefficients were derived from experimental results. The experimental

A. Arteconi; G. Di Nicola; M. Moglie; G. Santori; R. Stryjek

2010-01-01

203

Semi-volatile and particulate emissions from the combustion of alternative diesel fuels  

Microsoft Academic Search

Motor vehicle emissions are a major anthropogenic source of air pollution and contribute to the deterioration of urban air quality. In this paper, we report results of a laboratory investigation of particle formation from four different alternative diesel fuels, namely, compressed natural gas (CNG), dimethyl ether (DME), biodiesel, and diesel, under fuel-rich conditions in the temperature range of 800–1200°C at

Sukh Sidhu; John Graham; Richard Striebich

2001-01-01

204

Electroless nickel-phosphorus coating on poly (ether ether ketone)/carbon nanotubes composite  

NASA Astrophysics Data System (ADS)

In order to improve electromagnetic shielding property of poly (ether ether ketone)/carbon nanotubes composite, a nickel-phosphorus coating was covered on the composite by electroless plating. The morphologies of the substrates and the coatings were characterized by SEM. XPS was performed to analyze the surface composition and chemical states before and after chemical etching. The results showed that lots of microscopic holes appeared and evenly distributed on the surface, and the concentration of hydrophilic groups on the surface increased after the composite was etched. Thermal shock test showed that the adhesive strength between the coating and the composite was good.

Zhai, Tong; Di, Lizhi; Yang, De'an

2014-05-01

205

Synthesis and characteristics of polyarylene ether sulfones  

NASA Technical Reports Server (NTRS)

A method utilizing potassium carbonate/dimethyl acetamide, as base and solvent respectively, was used for the synthesis of several homopolymers and copolymers derived from various bisphenols. It is demonstrated that this method deviates from simple second order kinetics; this deviation being due to the heterogeneous nature of the reaction. Also, it is shown that a liquid induced crystallization process can improve the solvent resistance of these polymers. Finally, a Monte Carlo simulation of the triad distribution of monomers in nonequilibrium copolycondensation is discussed.

Viswanathan, R.; Johnson, B. C.; Ward, T. C.; Mcgrath, J. E.

1981-01-01

206

Poly (Aryl Ether Ketones) Bearing Alkylated Side Chains  

NASA Technical Reports Server (NTRS)

This invention relates generally to poly(aryl ether ketones) bearing alkylated side chains. It relates particularly to soluble, thermally stable. low dielectric poly(aryl ether ketones) with alkylated side chains and especially to films and coatings thereof. These poly(aryl ether ketones) have a structural formula wherein Y is selected from the group consisting of CF3 and CH3; and wherein R is C(sub n)H(sub (2n+1)) and n = 11-18.

Cassidy, Patrick E. (Inventor); Fitch, John W., III (Inventor); Gronewald, Scott D. (Inventor); St.Clair, Ann K. (Inventor); Stoakley, Diane M. (Inventor)

2002-01-01

207

Synthesis of a Lithium Specific Chromogenic Crown Ether  

Microsoft Academic Search

Recent experiments have shown that monobasic chromophoric crown ethers have very selective extraction behavior making them useful as analytical organic reagents. The chromogenic crown ethers are synthesized by reacting a chromophore like picryl chloride to an aminobenzo crown ether. One such compound 2?4?-dinitro-6-trifluoromethylphenyl-4?-aminobenzo-15-crown-5 (1) exhibits linear response to K from 700-5ppm in the presence of 3000ppm Na.

G. E. Pacey; Y. P. Wu; B. P. Bubnis

1981-01-01

208

Synthesis and photopolymerization of propenyl ether and epoxy functionalized siloxanes  

NASA Astrophysics Data System (ADS)

The reactive precursors, 1-allyloxy-4(1-propenoxy)butane and allyl-epoxy-ester, were synthesized. The synthesis of propenyl ether and epoxy functionalized siloxanes has been achieved by the controlled, rhodium-catalyzed, chemoselective hydrosilation of allyl ether with various H-functional siloxanes. It was shown that the hydrosilation proceeds exclusively at the allyl ether group of allyloxy-propenoxybutane without participation at the propenyl ether group. The photoinduced cationic polymerization of these monomers was studied and found to be all highly reactive.

Kim, W. G.; Ahn, H. K.; Lee, H. W.; Kim, S. H.; Crivello, J. V.

2003-01-01

209

Divinyl ether synthase gene and protein, and uses thereof  

DOEpatents

The present invention relates to divinyl ether synthase genes, proteins, and methods of their use. The present invention encompasses both native and recombinant wild-type forms of the synthase, as well as mutants and variant forms, some of which possess altered characteristics relative to the wild-type synthase. The present invention also relates to methods of using divinyl ether synthase genes and proteins, including in their expression in transgenic organisms and in the production of divinyl ether fatty acids, and to methods of suing divinyl ether fatty acids, including in the protection of plants from pathogens.

Howe, Gregg A. (East Lansing, MI); Itoh, Aya (Tsuruoka, JP)

2011-09-13

210

40 CFR 721.10416 - Brominated polyphenyl ether (generic) (P-11-264).  

Code of Federal Regulations, 2014 CFR

...Brominated polyphenyl ether (generic) (P-11-264). 721.10416 Section 721...Brominated polyphenyl ether (generic) (P-11-264). (a) Chemical substance...generically as brominated polyphenyl ether (PMN P-11-264) is subject to...

2014-07-01

211

40 CFR 721.10416 - Brominated polyphenyl ether (generic) (P-11-264).  

Code of Federal Regulations, 2012 CFR

...Brominated polyphenyl ether (generic) (P-11-264). 721.10416 Section 721...Brominated polyphenyl ether (generic) (P-11-264). (a) Chemical substance...generically as brominated polyphenyl ether (PMN P-11-264) is subject to...

2012-07-01

212

40 CFR 721.10416 - Brominated polyphenyl ether (generic) (P-11-264).  

Code of Federal Regulations, 2013 CFR

...Brominated polyphenyl ether (generic) (P-11-264). 721.10416 Section 721...Brominated polyphenyl ether (generic) (P-11-264). (a) Chemical substance...generically as brominated polyphenyl ether (PMN P-11-264) is subject to...

2013-07-01

213

Methyl Tertiary Butyl Ether (MTBE): Drinking Water  

NSDL National Science Digital Library

MTBE, a gasoline oxygenater additive, has been detected in ground water sources throughout different parts of the country. These ground water sources are often the source of drinking water, and the presence of methyl tertiary butyl ether in even minute quantities can make the water undrinkable. Research to date has not conclusively identified any quantitative level at which serious health risks may occur. This site provides information on behalf of the Environmental Protection Agency on the concerns and occurence of MTBE in drinking water.

214

Antifungal ether diglycosides from Matayba guianensis Aublet.  

PubMed

Since the 1960s, fungal infections have become a major worldwide public health problem. Antifungal treatments have many limitations, such as toxicity and resistance. Matayba guianensis Aublet (Sapindaceae) was chemically investigated as part of our ongoing search for lead molecules against fungi in the Brazilian Cerrado biome. The ethanolic extract of M. guianensis root bark revealed the presence of two previously unreported ether diglycosides: matayoside E (1) and F (2) with anti Candida activity, along with two known compounds: cupanioside (3) and stigmasterol (4). PMID:24485783

de Assis, Polyana A; Theodoro, Phellipe N E T; de Paula, José E; Araújo, Ana J; Costa-Lotufo, Letícia V; Michel, Sylvie; Grougnet, Raphaël; Kritsanida, Marina; Espindola, Laila S

2014-03-01

215

40 CFR 721.8160 - Propanoic acid, 2,2-dimethyl-, ethenyl ester.  

Code of Federal Regulations, 2012 CFR

...721.8160 Propanoic acid, 2,2-dimethyl...identified as propanoic acid, 2,2-dimethyl...method, the company's personal protective...in the following state(s): Open liquid...substances hexanedioic acid, diethenyl ester,...

2012-07-01

216

40 CFR 721.8160 - Propanoic acid, 2,2-dimethyl-, ethenyl ester.  

Code of Federal Regulations, 2014 CFR

...721.8160 Propanoic acid, 2,2-dimethyl...identified as propanoic acid, 2,2-dimethyl...method, the company's personal protective...in the following state(s): Open liquid...substances hexanedioic acid, diethenyl ester,...

2014-07-01

217

40 CFR 721.8160 - Propanoic acid, 2,2-dimethyl-, ethenyl ester.  

Code of Federal Regulations, 2011 CFR

...721.8160 Propanoic acid, 2,2-dimethyl...identified as propanoic acid, 2,2-dimethyl...method, the company's personal protective...in the following state(s): Open liquid...substances hexanedioic acid, diethenyl ester,...

2011-07-01

218

40 CFR 721.8160 - Propanoic acid, 2,2-dimethyl-, ethenyl ester.  

Code of Federal Regulations, 2013 CFR

...721.8160 Propanoic acid, 2,2-dimethyl...identified as propanoic acid, 2,2-dimethyl...method, the company's personal protective...in the following state(s): Open liquid...substances hexanedioic acid, diethenyl ester,...

2013-07-01

219

Sulfonated poly(ether ether ketone)-based composite membrane for polymer electrolyte membrane fuel cells  

Microsoft Academic Search

The solid proton conductor zirconium phosphate sulfophenylenphosphonate of composition Zr(HPO4)0.65(SPP)1.35 where SPP denotes metasulfophenylenphosphonate was prepared in the amorphous gel form in dimethyl formamide (DMF) and characterized by 31P NMR. The composite membranes of SPEEK up to 50wt.% of zirconium phosphate sulfophenylenphosphonate content were prepared by introducing the solid proton conductor from the gel. The composite membranes were characterized using

Palanichamy Krishnan; Jin-Soo Park; Tae-Hyun Yang; Won-Yong Lee; Chang-Soo Kim

2006-01-01

220

Polybrominated Diphenyl Ethers in the Sediments of the Great Lakes.  

E-print Network

Polybrominated Diphenyl Ethers in the Sediments of the Great Lakes. 4. Influencing Factors, Trends in the five Laurentian Great Lakes, and each was analyzed for 10 congeners of polybrominated diphenyl ethers-PBDE congeners (9BDEs) in the sediments of all the Great Lakes was estimated to be approximately 5.2 ( 1.1 tonnes

Rockne, Karl J.

221

48. BUILDING NO. 519, ETHER AND ALCOHOL RECOVERY HOUSE, INTERIOR, ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

48. BUILDING NO. 519, ETHER AND ALCOHOL RECOVERY HOUSE, INTERIOR, 5TH LEVEL, LOOKING NORTH AT ETHER AND ALCOHOL CONDENSERS AT TOP OF TOWER. - Picatinny Arsenal, 500 Area, Powder Factory & Power House, State Route 15 near I-80, Dover, Morris County, NJ

222

Introducing the Oxypro process: A new refinery ethers process  

Microsoft Academic Search

The new Oxypro process developed by UOP is a unique, low-cost, refinery-based catalytic process for the production of diisopropyl ether (DIPE) from propylene and water. The ether DIPE has high octane, low vapor pressure, and excellent gasoline blending properties. The Oxypro process is especially well suited for processing propylene derived from the fluid catalytic cracking unit (FCCU) within the refinery.

S. P. Davis; T. L. Marker; R. J. Schmidt; W. H. Keesom

1995-01-01

223

The Ether Wind and the Global Positioning System.  

ERIC Educational Resources Information Center

Explains how students can perform a refutation of the ether theory using information from the Global Positioning System (GPS). Discusses the functioning of the GPS, qualitatively describes how position determination would be affected by an ether wind, and illustrates the pertinent ideas with a simple quantitative model. (WRM)

Muller, Rainer

2000-01-01

224

Surface Modification of Silicone Elastomer Using Perfluorinated Ether  

E-print Network

Surface Modification of Silicone Elastomer Using Perfluorinated Ether Shilpa K. Thanawala and Manoj(PFE)tothesiloxanenetworkbyahydrosilationreaction.Examination of the surface by contact angle and X-ray photoelectron spectroscopy revealed that the perfluorinated ether(vinyl alcohol)s,5 organic sulfides,6 and perfluorinated polyesters,7,8 have been used to create release coatings

Chaudhury, Manoj K.

225

46. BUILDING NO. 519, ETHER AND ALCOHOL RECOVERY HOUSE, INTERIOR, ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

46. BUILDING NO. 519, ETHER AND ALCOHOL RECOVERY HOUSE, INTERIOR, CONTROL PANEL LEVEL (2ND DECK) OF ETHER AND ALCOHOL STILL BUILDING, LOOKING NORTH, SHOWING TWO ALCOHOL DISTILLATION TOWERS BEHIND 'MIXED SOLVENT UNIT' CONTROL PANEL. - Picatinny Arsenal, 500 Area, Powder Factory & Power House, State Route 15 near I-80, Dover, Morris County, NJ

226

47. BUILDING NO. 519, ETHER AND ALCOHOL RECOVERY HOUSE, INTERIOR, ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

47. BUILDING NO. 519, ETHER AND ALCOHOL RECOVERY HOUSE, INTERIOR, 4TH LEVEL, LOOKING NORTH AT TOPS OF ALCOHOL AND ETHER DISTILLATION TOWERS. - Picatinny Arsenal, 500 Area, Powder Factory & Power House, State Route 15 near I-80, Dover, Morris County, NJ

227

Emergent gravity and ether-drift experiments  

E-print Network

According to several authors, gravity might be a long-wavelength phenomenon emerging in some 'hydrodynamic limit' from the same physical, flat-space vacuum viewed as a form of superfluid medium. In this framework, light might propagate in an effective acoustic geometry and exhibit a tiny anisotropy that could be measurable in the present ether-drift experiments. By accepting this view of the vacuum, one should also consider the possibility of sizeable random fluctuations of the signal that reflect the stochastic nature of the underlying `quantum ether' and could be erroneously interpreted as instrumental noise. To test the present interpretation, we have extracted the mean amplitude of the signal from various experiments with different systematics, operating both at room temperature and in the cryogenic regime. They all give the same consistent value A > = O (10^{-15}) which is precisely the magnitude expected in an emergent-gravity approach, for an apparatus placed on the Earth's surface. Since physical implications could be substantial, it would be important to obtain more direct checks from the instantaneous raw data and, possibly, with new experimental set-ups operating in gravity-free environments.

M. Consoli; L. Pappalardo

2010-05-04

228

Biosynthesis of archaeal membrane ether lipids  

PubMed Central

A vital function of the cell membrane in all living organism is to maintain the membrane permeability barrier and fluidity. The composition of the phospholipid bilayer is distinct in archaea when compared to bacteria and eukarya. In archaea, isoprenoid hydrocarbon side chains are linked via an ether bond to the sn-glycerol-1-phosphate backbone. In bacteria and eukarya on the other hand, fatty acid side chains are linked via an ester bond to the sn-glycerol-3-phosphate backbone. The polar head groups are globally shared in the three domains of life. The unique membrane lipids of archaea have been implicated not only in the survival and adaptation of the organisms to extreme environments but also to form the basis of the membrane composition of the last universal common ancestor (LUCA). In nature, a diverse range of archaeal lipids is found, the most common are the diether (or archaeol) and the tetraether (or caldarchaeol) lipids that form a monolayer. Variations in chain length, cyclization and other modifications lead to diversification of these lipids. The biosynthesis of these lipids is not yet well understood however progress in the last decade has led to a comprehensive understanding of the biosynthesis of archaeol. This review describes the current knowledge of the biosynthetic pathway of archaeal ether lipids; insights on the stability and robustness of archaeal lipid membranes; and evolutionary aspects of the lipid divide and the LUCA. It examines recent advances made in the field of pathway reconstruction in bacteria. PMID:25505460

Jain, Samta; Caforio, Antonella; Driessen, Arnold J. M.

2014-01-01

229

(4,4?-Dimethyl-2,2?-bipyridine-?2 N,N?)(dimethyl sulfoxide-?O)diiodidozinc(II)  

PubMed Central

In the title compound, [ZnI2(C12H12N2)(C2H6OS)], the ZnII ion is coordinated by two N atoms from a 4,4?-dimethyl-2,2?-bipyridine ligand, one O atom from a dimethyl sulfoxide mol­ecule and two I atoms in a distorted trigonal-bipyramidal geometry. Intra­molecular C—H?O hydrogen bonds and inter­molecular ?–? stacking inter­actions between the pyridine rings [centroid–centroid distances = 3.637?(4) and 3.818?(4)?Å] are present in the crystal structure. PMID:21589277

Yousefi, Mohammad

2010-01-01

230

Crowning Proteins: Modulating the Protein Surface Properties using Crown Ethers**  

PubMed Central

Crown ethers are small, cyclic polyethers that have found wide-spread use in phase-transfer catalysis and, to a certain degree, in protein chemistry. Crown ethers readily bind metallic and organic cations, including positively charged amino acid side chains. We elucidated the crystal structures of several protein-crown ether co-crystals grown in the presence of 18-crown-6. We then employed biophysical methods and molecular dynamics simulations to compare these complexes with the corresponding apoproteins and with similar complexes with ring-shaped low-molecular-weight polyethylene glycols. Our studies show that crown ethers can modify protein surface behavior dramatically by stabilizing either intra- or intermolecular interactions. Consequently, we propose that crown ethers can be used to modulate a wide variety of protein surface behaviors, such as oligomerization, domain–domain interactions, stabilization in organic solvents, and crystallization. PMID:25287606

Lee, Cheng-Chung; Maestre-Reyna, Manuel; Hsu, Kai-Cheng; Wang, Hao-Ching; Liu, Chia-I; Jeng, Wen-Yih; Lin, Li-Ling; Wood, Richard; Chou, Chia-Cheng; Yang, Jinn-Moon; Wang, Andrew H-J

2014-01-01

231

Carbon-carbon bond cleavage of 1,2-hydroxy ethers b7 vanadium(V) dipicolinate complexes  

SciTech Connect

The development of alternatives to current petroleum-based fuels and chemicals is becoming increasingly important due to concerns over climate change, growing world energy demand, and energy security issues. Using non-food derived biomass to produce renewable feedstocks for chemicals and fuels is a particularly attractive possibility. However, the majority of biomass is in the form of lignocellulose, which is often not fully utilized due to difficulties associated with breaking down both lignin and cellulose. Recently, a number of methods have been reported to transform cellulose directly into more valuable materials such as glucose, sorbitol, 5-(chloromethyl)furfural, and ethylene glycol. Less progress has been made with selective transformations of lignin, which is typically treated in paper and forest industries by kraft pulping (sodium hydroxide/sodium sulfide) or incineration. Our group has begun investigating aerobic oxidative C-C bond cleavage catalyzed by dipicolinate vanadium complexes, with the idea that a selective C-C cleavage reaction of this type could be used to produce valuable chemicals or intermediates from cellulose or lignin. Lignin is a randomized polymer containing methoxylated phenoxy propanol units. A number of different linkages occur naturally; one of the most prevalent is the {beta}-O-4 linkage shown in Figure 1, containing a C-C bond with 1,2-hydroxy ether substituents. While the oxidative C-C bond cleavage of 1,2-diols has been reported for a number of metals, including vanadium, iron, manganese, ruthenium, and polyoxometalate complexes, C-C bond cleavage of 1,2-hydroxy ethers is much less common. We report herein vanadium-mediated cleavage of C-C bonds between alcohol and ether functionalities in several lignin model complexes. In order to explore the scope and potential of vanadium complexes to effect oxidative C-C bond cleavage in 1,2-hydroxy ethers, we examined the reactivity of the lignin model complexes pinacol monomethyl ether (A), 2-phenoxyethanol (B), and 1,2-diphenyl-2-methoxyethanol (C) (Figure 1). Reaction of (dipic)V{sup V}(O)O{sup i}Pr (1a) or (dipic)V{sup v}(O)OEt (lb) with A, B, or C in acetonitrile yielded new vanadium(V) complexes where the alcohol-ether ligand was bound in a chelating fashion. From the reaction of 1b with pinacol monomethyl ether (A) in acetonitrile solution, (dipic)V{sup v}(O)(pinOMe) (2) (PinOMe = 2,3-dimethyl-3-methoxy-2-butanoxide) was isolated in 61 % yield. Reaction of 1b with 2-phenoxyethanol (B) in acetonitrile gave the new complex (dipic)V{sup v}(O)(OPE) (3) (OPE = 2-phenoxyethoxide), which was isolated in 76% yield. In a similar fashion, 1a reacted with 1,2-diphenyl-2-methoxyethanol (C) to give (dipic)V(O)(DPME) (4) (DPME = 1,2-diphenyl-2-methoxyethoxide), which was isolated in 39% yield. Complexes 2, 3, and 4 were characterized by {sup 1}H NMR and IR spectroscopy, elemental analysis, and X-ray crystallography. Compared to the previously reported vanadium(V) pinacolate complex (dipic)V(O)(pinOH) the X-ray structure of complex 2 reveals a slightly shorter V = O bond, 1.573(2) {angstrom} vs 1.588(2) {angstrom} for the pinOH structure. Complexes 3 and 4 display similar vanadium oxo bond distances of 1.568(2) {angstrom} and 1.576(2) {angstrom}, respectively. All three complexes show longer bonds to the ether-oxygen trans to the oxo (2.388(2) {angstrom} for 2, 2.547(2) {angstrom} for 3, and 2.438(2) {angstrom} for 4) than to the hydroxy-oxygen in the pinOH structure (2.252(2) {angstrom}).

Hanson, Susan K [Los Alamos National Laboratory; Gordon, John C [Los Alamos National Laboratory; Thorn, David L [Los Alamos National Laboratory; Scott, Brian L [Los Alamos National Laboratory; Baker, R Tom [Los Alamos National Laboratory

2009-01-01

232

Toxic effects of decabromodiphenyl ether (BDE-209) on human embryonic kidney cells  

PubMed Central

Polybrominated diphenyl ethers (PBDEs) are widely used as flame-retardant additives in consumer and household products and can escape into the environment over time. PBDEs have become a global environmental organic pollutant due to the properties of persistence, toxicity, and bioaccumulation. The well-studied toxic effects of PBDEs mainly include thyroid hormone disruption and neurotoxicity. There is no consistent conclusions on the carcinogenic potential of PBDEs to date. Here, we explored the toxic effects of BDE-209 on human embryonic kidney cells (HEK293T). The comparison of the gene expression profiles of HEK293T cells with BDE-209 treatment and the negative control found that BDE-209 exposure may alter nucleosome organization through significantly changing the expression of histone gene clusters. The remodeled chromatin structure could further disturb systemic lupus erythematosus as one of the toxic effects of BDE-209. Additionally, gene sets of different cancer modules are positively correlated with BDE-209 exposure. This suggests that BDE-209 has carcinogenic potential for a variety of tumors. Collectively, BDE-209 has a broader toxicity not limited to disruption of thyroid hormone-related biological processes. Notably, the toxic effects of BDE-209 dissolved in dimethyl sulfoxide (DMSO) is not the simply additive effects of BDE-209 and DMSO alone. PMID:24834073

Li, Min; Liu, Zhenping; Gu, Liang; Yin, Rong; Li, Huarong; Zhang, Xiaobai; Cao, Tongcheng; Jiang, Cizhong

2014-01-01

233

Preparation of poly(ether ether ketone)-based polymer electrolytes for fuel cell membranes using grafting technique  

Microsoft Academic Search

Poly(ether ether ketone) (PEEK)-based polymer electrolyte membranes (PEMs) was successfully prepared by radiation grafting of a styrene monomer into PEEK films and the consequent selective sulfonation of the grafting chains in the film state. Using milder sulfonation, the sulfonation reactions proceeded at the grafted chains in preference to the phenylene rings of PEEK main chains; as a result, the grafted

Shin Hasegawa; Yasuyuki Suzuki; Yasunari Maekawa

2008-01-01

234

Radiolabeled dimethyl branched long chain fatty acid for heart imaging  

DOEpatents

A radiolabeled long chain fatty acid for heart imaging that has dimethyl branching at one of the carbons of the chain which inhibits the extent to which oxidation can occur. The closer to the carboxyl the branching is positioned, the more limited the oxidation, thereby resulting in prolonged retention of the radiolabeled compound in the heart.

Knapp, Jr., Furn F. (Oak Ridge, TN); Goodman, Mark M. (Knoxville, TN); Kirsch, Gilbert (Woippy, FR)

1988-08-16

235

DIMETHYL SULFOXIDE ACCELERATES MUSTARD GAS-INDUCED SKIN PATHOLOGY  

Microsoft Academic Search

SUMMARY Dimethyl sulfoxide (DMSO), when used as a percutaneous carrier or as a required solvent for drugs, may have modulating effects on drug mechanisms and untoward effects on subject tissues. In this collaborative study, anhydrous DMSO was used as a vehicle for peptide caspase inhibitors of sulfur mustard gas (HD)-induced apoptosis in hairless guinea pig skin. Results of the inhibition

John P. Petrali; Tracey A. Hamilton; Betty J. Benton; Dana R. Anderson; Wesley Holmes; Robert K. Kan; Christina P. Tompkins; Radharaman Ray

236

Spiroborate Ester-Mediated Asymmetric Synthesis of ?-Hydroxy Ethers and its Conversion to Highly Enantiopure ?-Amino Ethers  

PubMed Central

Borane-mediated reduction of aryl and alkyl ketones with ?-aryl- and ?-pyridyloxy groups affords ?-hydroxy ethers in high enantiomeric purity (up to 99% ee) and in good yield, using as catalyst 10 mol % of spiroborate ester 1 derived from (S)-diphenylprolinol. Representative ?-hydroxy ethers are successfully converted to ?-amino ethers, with minor epimerization, by phthalimide substitution under Mitsunobu’s conditions followed by hydrazinolysis, to obtain primary amino ethers or by imide reduction with borane to afford ?-2,3-dihydro-1H-isoindol ethers. Non-racemic Mexiletine and nAChR analogues with potential biological activity are also synthesized in excellent yield by mesylation of key ?-hydroxy pyridylethers and substitution with 5, 6 and 7 member ring heterocyclic amines. PMID:19413288

Huang, Kun; Ortiz-Marciales, Margarita; Correa, Wildeliz; Pomales, Edgardo; López, Xaira Y.

2009-01-01

237

Origin of mechanical modifications in poly (ether ether ketone)/carbon nanotube composite  

SciTech Connect

Variations in the hardness of a poly (ether ether ketone) beam electrically modified with multi-walled carbon nanotubes (MWCNT, 0.5%-3%) are investigated. It is shown that both rupture and hardness variations correlate with the changes in carbon nanotube concentration when using micro indentation and extended Raman imaging. Statistical analysis of the relative spectral intensities in the Raman image is used to estimate local tube concentration and polymer crystallinity. We show that the histogram of the Raman D band across the image provides information about the amount of MWCNTs and the dispersion of MWCNTs in the composite. We speculate that we have observed a local modification of the ordering between pure and modified polymer. This is partially supported by small angle neutron scattering measurements, which indicate that the agglomeration state of the MWCNTs is the same at the concentrations studied.

Pavlenko, Ekaterina; Puech, Pascal; Bacsa, Wolfgang, E-mail: wolfgang.bacsa@cemes.fr [CEMES-CNRS and University of Toulouse, 29 Jeanne Marvig, 31055 Toulouse (France); Boyer, François; Olivier, Philippe [Université de Toulouse, Institut Clément Ader, I.U.T. Université Paul Sabatier - 133C Avenue de Rangueil - B.P. 67701, 31077 Toulouse CEDEX 4 (France); Sapelkin, Andrei [School of Physics and Astronomy, Queen Mary, University of London, Mile End Road, E1 4NS London (United Kingdom); King, Stephen; Heenan, Richard [ISIS Facility, Rutherford Appleton Laboratory, Chilton, OX11 0QX Didcot (United Kingdom); Pons, François; Gauthier, Bénédicte; Cadaux, Pierre-Henri [AIRBUS FRANCE (B.E. M and P Toulouse), 316 Route de Bayonne, 31060 Toulouse (France)

2014-06-21

238

Atomistic and mesoscale simulation of polymer electrolyte membranes based on sulfonated poly(ether ether ketone)  

NASA Astrophysics Data System (ADS)

We report results of multiscale simulations of a hydrated ionomer membrane based on sulfonated poly(ether ether ketone) (sPEEK) that constitutes an important class of the promising membrane materials for fuel cell applications. Using atomistic and field-theoretic simulation techniques - classical molecular dynamics and dynamic density functional theory - we study the processes of self-organization in sPEEK membranes in the presence of water. At the same water content, both simulation techniques predict a similar structure of the hydrated membranes. The observed membrane morphology can be represented as a topologically complex sponge-like network consisting of irregular water-filled channels. Compared to Nafion, the channels in the sPEEK membrane are narrower. Nevertheless, the estimated percolation threshold in sPEEK is lower than for Nafion.

Komarov, P. V.; Veselov, I. N.; Chu, P. P.; Khalatur, P. G.; Khokhlov, A. R.

2010-03-01

239

Amperometric dimethyl sulfoxide sensor using dimethyl sulfoxide reductase from Rhodobacter sphaeroides.  

PubMed

An amperometric dimethyl sulfoxide (DMSO) sensor was constructed based on DMSO reductase (DMSO-R). DMSO-R from Rhodobacter sphaeroides f. sp. denitrificans was immobilized by BSA-glutaraldehyde cross-linking at the surface of a glassy carbon electrode. Mediators were added to the sample solution in a free form. Several mediators (methyl viologen (MV), benzyl viologen (BV), neutral red (NR), safranin T (ST), FMN, phenazine methosulfate (PMS)), which can donate electrons to DMSO-R, were examined with the DMSO-R immobilized electrode. Among them MV was selected as a model mediator because of its wide linear response range and fast response time. The response current was effected by the measurement temperature but hardly effected by the pH of the sample solution. The response current was increased with the measurement temperature up to 50 degrees C. A response current was observed at 1 microM DMSO and the response time was 20 s under the optimum conditions. The response was observed for approximately 2 weeks. By the reduction of Schiff base in the cross-linking layer the response range became narrower but most of the response current was retained at 300 microM of DMSO for more than 5 weeks. PMID:12706586

Abo, Mitsuru; Ogasawara, Yuki; Tanaka, Yoshikiyo; Okubo, Akira; Yamazaki, Sunao

2003-05-01

240

Methyl Tertiary Butyl Ether (MTBE) Groundwater Contamination  

NSDL National Science Digital Library

Methyl tertiary-butyl ether (MTBE), a fuel additive, is highly mobile in groundwater, dissolving and traveling faster than the other petroleum constituents which tend to biodegrade and adsorb to soil particles. This unit will introduce the problem of pollutants as they move through the various soil layers and contaminate the groundwater and challenge the students to investigate the effects of MTBE spills in the environment by researching the available literature on fuel oxygenates and learning their mode of transport through the soil. Experimentally determined data, obtained in lab activities, will facilitate building models of the contamination process of the groundwater. Mathematics modeling will involve the use of spreadsheet analysis of real-world-data obtained online.

241

High temperature fuel cell membranes based on poly(arylene ether)s containing benzimidazole groups  

SciTech Connect

Development of new high-performance polymer membranes that retain their proton conductivity under low humidity conditions is one of the most critical requirements to commercialize PEMFC systems. Current sulfonated proton exchange membranes acquire proton conductivity by water that solvates ion and carries proton. Consequently, a loss of water under low RH conditions immediately results in a loss of proton conductivity. One approach to maintain proton conductivity under low RH conditions is to replace water with a less volatile proton solvent. Kreuer has pointed out the possibility to develop fully polymeric proton-conducting membranes based on nitrogen-containing heterocycles such as imidazole, benzimidazole, and pyrazole. We have attempted to blend those less volatile proton solvent with sulfonated copolymers such as polystyrene sulfonic acid, Nafion, poly(arylene ether sulfone, BPSH-xx). [Ref. DOE review meeting 2007 and 2008] However, we observed that imidazole was slowly sublimated out as temperature and humidity increases which could cause poisoning of electro-catalyst, corrosion and losing conductivity. In this presentation, we report the synthesis of novel poly(arylene ether sulfone)s containing benzimidazole groups These benzimidazole containing polymer was blended with sulfonated poly(arylene ether sulfone). In the blend system, benzimidazole group attached to the polysulfone acts as a medium through the basic nitrogen for transfer of protons between the sulfonic acid groups. Proton conductivity of the blend membranes was investigated as a function of water content at 80 C and compared the performance with water based proton conduction system.

Kim, Dae Sik [Los Alamos National Laboratory; Kim, Yu Seung [Los Alamos National Laboratory; Lee, Kwan - Soo [Los Alamos National Laboratory; Boncella, James M [Los Alamos National Laboratory; Kuiper, David [Los Alamos National Laboratory; Guiver, Michael D [CANADA

2009-01-01

242

Crown Ethers in Nonaqueous Electrolytes for Lithium/Air Batteries  

SciTech Connect

The effects of three crown ethers, 12-crown-4, 15-crown-5, and 18-crown-6, as additives and co-solvents in non-aqueous electrolytes on the cell performance of primary Li/air batteries operated in a dry air environment were investigated. Crown ethers have large effects on the discharge performance of non-aqueous electrolytes in Li/air batteries. A small amount (normally less than 10% by weight or volume in electrolytes) of 12-Crown-4 and 15-crown-5 reduces the battery performance and a minimum discharge capacity appears at the crown ether content of ca. 5% in the electrolytes. However, when the content increases to about 15%, both crown ethers improve the capacity of Li/air cells by about 28% and 16%, respectively. 15-Crown-5 based electrolytes even show a maximum discharge capacity in the crown ether content range from 10% to 15%. On the other hand, the increase of 18-crown-6 amount in the electrolytes continuously lowers of the cell performance. The different battery performances of these three crown ethers in electrolytes are explained by the combined effects from the electrolytes’ contact angle, oxygen solubility, viscosity, ionic conductivity, and the stability of complexes formed between crown ether molecules and lithium ions.

Xu, Wu; Xiao, Jie; Wang, Deyu; Zhang, Jian; Zhang, Jiguang

2010-02-04

243

Oxidative cleavage of diverse ethers by an extracellular fungal peroxygenase.  

PubMed

Many litter-decay fungi secrete heme-thiolate peroxygenases that oxidize various organic chemicals, but little is known about the role or mechanism of these enzymes. We found that the extracellular peroxygenase of Agrocybe aegerita catalyzed the H2O2-dependent cleavage of environmentally significant ethers, including methyl t-butyl ether, tetrahydrofuran, and 1,4-dioxane. Experiments with tetrahydrofuran showed the reaction was a two-electron oxidation that generated one aldehyde group and one alcohol group, yielding the ring-opened product 4-hydroxybutanal. Investigations with several model substrates provided information about the route for ether cleavage: (a) steady-state kinetics results with methyl 3,4-dimethoxybenzyl ether, which was oxidized to 3,4-dimethoxybenzaldehyde, gave parallel double reciprocal plots suggestive of a ping-pong mechanism (K(m)((peroxide)), 1.99 +/- 0.25 mM; K(m)((ether)), 1.43 +/- 0.23 mM; k(cat), 720 +/- 87 s(-1)), (b) the cleavage of methyl 4-nitrobenzyl ether in the presence of H2(18)O2 resulted in incorporation of 18O into the carbonyl group of the resulting 4-nitrobenzaldehyde, and (c) the demethylation of 1-methoxy-4-trideuteromethoxybenzene showed an observed intramolecular deuterium isotope effect [(k(H)/k(D))(obs)] of 11.9 +/- 0.4. These results suggest a hydrogen abstraction and oxygen rebound mechanism that oxidizes ethers to hemiacetals, which subsequently hydrolyze. The peroxygenase appeared to lack activity on macromolecular ethers, but otherwise exhibited a broad substrate range. It may accordingly have a role in the biodegradation of natural and anthropogenic low molecular weight ethers in soils and plant litter. PMID:19713216

Kinne, Matthias; Poraj-Kobielska, Marzena; Ralph, Sally A; Ullrich, René; Hofrichter, Martin; Hammel, Kenneth E

2009-10-23

244

Oxidative Cleavage of Diverse Ethers by an Extracellular Fungal Peroxygenase*  

PubMed Central

Many litter-decay fungi secrete heme-thiolate peroxygenases that oxidize various organic chemicals, but little is known about the role or mechanism of these enzymes. We found that the extracellular peroxygenase of Agrocybe aegerita catalyzed the H2O2-dependent cleavage of environmentally significant ethers, including methyl t-butyl ether, tetrahydrofuran, and 1,4-dioxane. Experiments with tetrahydrofuran showed the reaction was a two-electron oxidation that generated one aldehyde group and one alcohol group, yielding the ring-opened product 4-hydroxybutanal. Investigations with several model substrates provided information about the route for ether cleavage: (a) steady-state kinetics results with methyl 3,4-dimethoxybenzyl ether, which was oxidized to 3,4-dimethoxybenzaldehyde, gave parallel double reciprocal plots suggestive of a ping-pong mechanism (Km(peroxide), 1.99 ± 0.25 mm; Km(ether), 1.43 ± 0.23 mm; kcat, 720 ± 87 s?1), (b) the cleavage of methyl 4-nitrobenzyl ether in the presence of H218O2 resulted in incorporation of 18O into the carbonyl group of the resulting 4-nitrobenzaldehyde, and (c) the demethylation of 1-methoxy-4-trideuteromethoxybenzene showed an observed intramolecular deuterium isotope effect [(kH/kD)obs] of 11.9 ± 0.4. These results suggest a hydrogen abstraction and oxygen rebound mechanism that oxidizes ethers to hemiacetals, which subsequently hydrolyze. The peroxygenase appeared to lack activity on macromolecular ethers, but otherwise exhibited a broad substrate range. It may accordingly have a role in the biodegradation of natural and anthropogenic low molecular weight ethers in soils and plant litter. PMID:19713216

Kinne, Matthias; Poraj-Kobielska, Marzena; Ralph, Sally A.; Ullrich, René; Hofrichter, Martin; Hammel, Kenneth E.

2009-01-01

245

Synthesis of new cellulose ethers using Suzuki-Miyaura reactions.  

PubMed

Cellulose ethers are functionalized biopolymers that are industrially produced through drastic conditions employing gaseous reactants with a high risk of industrial accident. The cellulose ethers that are commercially available generally bear short carbon-chains. In this work, an alternative method using non-gaseous chemicals is proposed. It relies on the use of the Suzuki-Miyaura reaction employing mild, moisture- and air-stable conditions. Relatively innocuous reagents are used for this step, which allows the formation of a wide range of cellulose ethers bearing various functional groups with different chain-length. PMID:25458272

Goncalves, Cédric; Favre, Camille; Feuardant, Pierre; Klein, Sarah; Vaca-Garcia, Carlos; Cecutti, Christine; Thiébaud-Roux, Sophie; Vedrenne, Emeline

2015-02-13

246

Stereoselective synthesis of six- and seven-membered ether rings based on the ring expansion  

Microsoft Academic Search

Six- and seven-membered ether rings were stereoselectively synthesized based on the rearrangement of the cyclic ether with the simultaneous ring expansion. Treatment of ether having a mesylate or bromide group as the leaving group on the side chain with Zn(OAc)2 or AgOAc stereoselectively produced the ring expanded ether in good yield.

Tadashi Nakata; Sumihiro Nomura; Hiroko Matsukura

1996-01-01

247

State Restrictions on Methyl Tertiary Butyl Ether (released in AEO2006)  

EIA Publications

By the end of 2005, 25 states had barred, or passed laws banning, any more than trace levels of methyl tertiary butyl ether (MTBE) in their gasoline supplies, and legislation to ban MTBE was pending in 4 others. Some state laws address only MTBE; others also address ethers such as ethyl tertiary butyl ether (ETBE) and tertiary amyl methyl ether (TAME). Annual Energy Outlook 2006 assumes that all state MTBE bans prohibit the use of all ethers for gasoline blending.

2006-01-01

248

Tough poly(arylene ether) thermoplastics as modifiers for bismaleimides  

NASA Technical Reports Server (NTRS)

Several aspects of research on thermoplastics as toughness modifiers are discussed, including the contribution of the backbone chemistry and the concentration of the poly(arylene ether) thermoplastic to fracture toughness, influence of the molecular weight of the poly(arylene ether) thermoplastic on neat resin fracture toughness, and the morphology of the thermoplastic modified networks. The results show that fracture toughness of brittle bismaleimide resins can be improved significantly with poly(arylene ether) thermoplastic levels of 20 percent by weight, and that high molecular weight poly(arylene ether) based on bisphenol A provides the highest degree of toughening. Preliminary composite evaluation shows that improvements in neat resin toughness translate into carbon fabric composite.

Stenzenberger, H. D.; Roemer, W.; Hergenrother, P. M.; Jensen, B. J.

1989-01-01

249

POLYBROMINATED DIPHENYL ETHERS (PBDES) CONTAMINATION OF UNITED STATES FOOD  

EPA Science Inventory

Elevated levels of polybrominated diphenyl ethers (PBDEs), a type of brominated flame retardant, were recently detected in United States (U.S.) nursing mothers' milk. These halogenated compounds chemically and toxicologically resemble others such as polychlorinated biphenyls (PC...

250

ANAEROBIC MICROBIAL REDUCTIVE DEBROMINATION OF POLYBROMINATED DIPHENYL ETHERS  

EPA Science Inventory

Polybrominated diphenyl ether (PBDE) flame retardants have been detected in sediments, sewage sludge, fish, mammals (including humans), and air throughout the northern hemisphere. While concentrations of PCBs, DDT, and PCDDs in biota are generally decreasing, PBDE concentratio...

251

Experimental Pathology Laboratories, Inc. Methyl-Tertiary-Butyl Ether  

E-print Network

Experimental Pathology Laboratories, Inc. Methyl-Tertiary-Butyl Ether C00117F/00117-69 AMENDED PATHOLOGY QUALITY ASSESSMENT REVIEW AND PWG Toxicology Program Research Triangle Park, NC 27709 Submitted by: Experimental Pathology Laboratories, Inc

Baker, Chris I.

252

Experimental Pathology Laboratories, Inc. Ethyl-Tertiary-Butyl Ether  

E-print Network

Experimental Pathology Laboratories, Inc. Ethyl-Tertiary-Butyl Ether C00117/00117-64 AMENDED PATHOLOGY QUALITY ASSESSMENT REVIEW AND PWG COORDINATOR'S REPORT Park, NC 27709 Submitted by: Experimental Pathology Laboratories, Inc. Street Address: Mailing Address

Baker, Chris I.

253

PREDICTIONS OF AZEOTROPES FORMED FROM FLUORINATED ETHERS, ETHANES, AND PROPANES  

EPA Science Inventory

The paper discusses an evaluation of the potential for azeotrope formation and performance for fluorinated ethers, ethanes, and propanes. (NOTE: The synthesis of new non-chlorinated refrigerants expands the base of alternatives for replacing ozone-depleting chlorofluorocarbons (O...

254

36. BUILDINGS NO. 519, ETHER AND ALCOHOL RECOVERY HOUSE, AND ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

36. BUILDINGS NO. 519, ETHER AND ALCOHOL RECOVERY HOUSE, AND NO. 523, REFRIGERATION PLANT BUILDING, LOOKING EAST. - Picatinny Arsenal, 500 Area, Powder Factory & Power House, State Route 15 near I-80, Dover, Morris County, NJ

255

44. BUILDING NO. 519, ETHER AND ALCOHOL RECOVERY HOUSE, INTERIOR, ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

44. BUILDING NO. 519, ETHER AND ALCOHOL RECOVERY HOUSE, INTERIOR, LOOKING UP DISTILLATION TOWER FROM 2ND LEVEL. - Picatinny Arsenal, 500 Area, Powder Factory & Power House, State Route 15 near I-80, Dover, Morris County, NJ

256

FLUORINATED ETHERS--A NEW SERIES OF CFC SUBSTITUTES  

EPA Science Inventory

The paper discusses fluorinated ethers, a new series of chlorofluorocarbon (CFC) substitutes. ompounds synthesized to produce substances with suitable refrigerant properties have generally left out sulfur, nitrogen, and oxygen. he reasons for these omissions are many and varied. ...

257

POLYBROMINATED DIPHENYL ETHERS IN HOUSE DUST AND CLOTHES DRYER LINT  

EPA Science Inventory

Polybrominated diphenyl ether (PBDE) flame retardants are now considered ubiquitous and persistent pollutants. Few studies have examined the concentrations of these chemicals in the home and here we report measurements of PBDEs in house dust samples collected from the Washington...

258

The surface chemistry of dimethyl disulfide on copper.  

PubMed

The surface chemistry of dimethyl disulfide (DMDS) is studied on a Cu(111) single crystal and a polished copper foil in ultrahigh vacuum as a basis for understanding its tribological chemistry using a combination of temperature-programmed desorption (TPD), reflection-absorption infrared spectroscopy (RAIRS), and X-ray photoelectron spectroscopy (XPS). Low-energy electron diffraction reveals that the polished foil becomes ordered on heating in vacuo and displays identical surface chemistry to that found on the Cu(111) surface. Dimethyl disulfide reacts with the copper surface at 80 K to form thiolate species. Heating the surface to ?230 K causes a small portion of the thiolate species to decompose to form methyl groups adsorbed on the surface. Further heating results in methane and C(2) hydrocarbon desorption at ?426 K, due to a reaction of adsorbed methyl species, to completely remove carbon from the surface and to deposit atomic sulfur. PMID:20617851

Furlong, Octavio J; Miller, Brendan P; Li, Zhenjun; Walker, Joshua; Burkholder, Luke; Tysoe, Wilfred T

2010-11-01

259

Dimethyl­ammonium 3-carb­oxy­benzoate  

PubMed Central

The asymmetric unit of the title organic salt, C2H8N+·C8H5O4 ?, consists of two dimethyl­ammonium cations and two 3-carb­oxy­benzoate anions. The 3-carb­oxy­benzoate anions are linked via strong inter­molecular and nearly symmetrical O—H?O hydrogen bonds forming infinite chains parallel to [111]. Neighbouring chains are further connected by the dimethyl­ammonium cations via N—H?O bonds, resulting in a double-chain-like structure. The dihedral angles of all carboxylate groups with respect to the phenylene rings are in the range 7.9?(1)–20.48?(9)°. PMID:22719555

Siddiqui, Tausif; Koteswara Rao, Vandavasi; Zeller, Matthias; Lovelace-Cameron, Sherri R.

2012-01-01

260

Diammonium hexakis(thiocyanato-?N)rhenate(IV) dimethyl sulfone tetrasolvate.  

PubMed

The title compound, (NH(4))(2)[Re(NCS)(6)]·4C(2)H(6)O(2)S, was obtained by solvothermal synthesis as part of a project on rhenium thiocyanate catalysts and starting materials for further aggregation to molecular magnets. The compound is the ammonium salt of octahedral hexakis(thiocyanato-?N)rhenate(IV) anions, which lie on centres of inversion. The dimethyl sulfone solvent molecules are involved in R(4)(2)(8) and D N-H···O hydrogen-bonded motifs. N-H···S and S···S short contacts are also present. Hydrogen-bonded ammonium-dimethyl sulfone layers alternate with layers formed by the complex anion (with S···S short contacts) parallel to (100). PMID:21540528

Kochel, Andrzej; Ho?y?ska, Ma?gorzata

2011-05-01

261

Global Distribution of Halogenated Dimethyl Bipyrroles in Marine Mammal Blubber  

Microsoft Academic Search

Four halogenated dimethyl bipyrroles (HDBPs), hypothesized to be naturally produced, were quantitated in marine mammal blubber\\u000a from a number of species obtained from various locations worldwide. HDBPs were found in samples from all locations studied.\\u000a Concentrations of total HDBPs (?HDBPs) ranged from 0.4 ng\\/g lipid weight in ringed seals (Phoca hispida) from the White Sea to 2,540 ng\\/g lipid weight

S. Tittlemier; A. Borrell; J. Duffe; P. J. Duignan; P. Fair; A. Hall; P. Hoekstra; K. M. Kovacs; M. M. Krahn; M. Lebeuf; C. Lydersen; D. Muir; T. O'Hara; M. Olsson; J. Pranschke; P. Ross; U. Siebert; G. Stern; S. Tanabe; R. Norstrom

2002-01-01

262

Influence of dimethyl formamide pulping of bagasse on pulp properties  

Microsoft Academic Search

Organosolv pulping of bagasse was conducted following a central composite design using a two-level factorial plan involving three pulping variables (temperature: 190–210°C, time: 120–180min, organic solvent charge: 40–60% dimethyl formamide). Responses of pulp properties (yield and holocellulose, ?-cellulose, kappa number, ash and ethanol–dichloromethane extractives contents) and the pH of the resulting wastewater to the process variables were analyzed using statistical

P. Rezayati-Charani; J. Mohammadi-Rovshandeh; S. J. Hashemi; S. Kazemi-Najafi

2006-01-01

263

Probing thermal interactions of ionic liquids with dimethyl sulfoxide.  

PubMed

Interactions between ionic liquids and dimethyl sulfoxide (DMSO) are probed by isothermal titration calorimetry. The excess partial molar enthalpies of ionic liquids H(IL)(E) in DMSO are discussed in terms of solute-solvent interactions. The specific interaction theory originally developed by Pitzer is used to analyze the apparent molar enthalpy ?(L) of ionic liquids in DMSO with the help of ion-interaction parameters. Furthermore, quantitative information on solvent reorganization and clathrate formation is obtained and interpreted. PMID:22344773

Rai, Gitanjali; Kumar, Anil

2012-05-14

264

Kerr constant of Dimethyl Terephthalate and Poly (Diethylene Glycol Terephthalate)  

Microsoft Academic Search

Summary Electrical, birefringence of Dimethyl Terephthalate (DMT) and Poly (Diethylene Glycol Terephthalate) (PDET) in p-dioxane solutions were measured at 20°C. The results were used to compute molar Kerr constants of both compounds at infinite dilution. The experimental results were mK>= = 780 and mK>= -732, both in units of 10-27m5V-2 mol-1, for DMT and PDET respectively. Theoretical analysis of mK>

Francisco Mendicuti; Enrique Saiz

1984-01-01

265

Responsive supramolecular gels constructed by crown ether based molecular recognition.  

PubMed

Responsive supramolecular gels were constructed from crown ether terminated four-arm star poly(epsilon-caprolactone) (PCL-DB24C8) and dibenzylammonium-terminated two-arm PCL-DBAS (see scheme), exploiting the formation of pseudorotaxane linkages between crown ether and ammonium moieties. The resultant supramolecular gels exhibit thermo- and pH-induced reversible gel-sol transition. PMID:19173355

Ge, Zhishen; Hu, Jinming; Huang, Feihe; Liu, Shiyong

2009-01-01

266

UV-radiation curing of vinyl ether-based coatings  

Microsoft Academic Search

Summaries  The photoinitiated polymerisation of different types of vinyl ether-based resins has been studied by real-time infrared spectroscopy.\\u000a The cationic initiated chain reaction was shown to proceed extensively within seconds, on UV exposure of divinyl ether monomers\\u000a in the presence of on arylsulfonium salt. Various factors affect the polymerisation kinetics, such as the type of photoinitiator,\\u000a the light intensity and the

C. Decker; F. Morel; D. Decker

2000-01-01

267

Influence of solvent on conformational equilibrium in phenyl glycidyl ether  

SciTech Connect

The conformational equilibrium in phenyl glycidyl ether in aprotic solvents was studied by the PMR method over a broad range of changes in the values of the dielectric constant. It was shown that the parameters of the multiplet of noncyclic methylene protons in the PMR spectrum of phenyl glycidyl ether are a sensitive indicator of the position of the conformation equilibrium in the glycidyl fragment. The specific interaction of the molecules of aromatic solvents with the epoxide ring has been discovered.

Chervinskii, A.Yu.; Shologon, I.M.; Kapkan, L.M.; Klebanov, M.S.

1985-09-01

268

Polybrominated diphenyl ethers detected in human adipose tissue from Spain  

Microsoft Academic Search

Polybrominated diphenyl ethers (PBDEs) were detected in 13 human adipose tissue samples from Spain, 3 women and 10 men. Tetra-, penta- and hexabrominated diphenyl ethers were determined at ng\\/g lipid (ppb) level in all the samples. The average TeBDE level was 1.36 ng\\/g, the average PeBDE was 0.93 ng\\/g and the HxBDE 1.83 ng\\/g. Human adipose tissue levels of PBDE

M. Meneses; H. Wingfors; M. Schuhmacher; J. L. Domingo; G. Lindström; B. v. Bavel

1999-01-01

269

Avoiding hydrolysis of fuel ether oxygenates during static headspace analysis.  

PubMed

The determination of fuel ether oxygenates in groundwater was found to be problematic when samples are preserved at pH < 2 and then analyzed using heated headspace sampling. Acid catalyzed the hydrolysis of tert-amyl methyl ether, ethyl tert-butyl ether, and methyl tert-butyl ether during headspace sampling when aqueous samples were heated at 80 degrees C, a typical temperature used for heated headspace sampling. Hydrochloric acid at pH 2 did not cause hydrolysis of oxygenate ethers in samples stored for 28 d at 4 degrees C. When trisodium phosphate was used to preserve the sample or to adjust the pH of samples preserved with acid before headspace sampling, the recovery of spiked ethers was excellent. The heated headspace method was also applicable for the determination of other fuel oxygenates including ethanol, tert-butyl alcohol (TBA), tert-amyl alcohol (TAA), isopropyl alcohol (IPA), acetone, and monoaromatic compounds found in gasoline including benzene, toluene, ethylbenzene, xylenes, and trimethylbenzenes. The method detection limits range from 0.1 to 0.2 microg/L for the ethers and aromatics. For alcohols and acetone, the method detection limits were 0.8 microg/L for TBA, 18 microg/L for ethanol, 1.2 microg/L for TAA, 5.5 microg/L for IPA, and 3.3 microg/L for acetone. The heated headspace method yielded accurate results for ether oxygenates in samples containing a wide range of gasoline concentrations (2500-100000 microg/L). PMID:14620829

Lin, Zhixun; Wilson, John T; Fine, Dennis D

2003-11-01

270

Antioxidant compounds from coriander ( Coriandrum sativum L.) etheric extract  

Microsoft Academic Search

Five fractions (?-carotene, ?-cryptoxanthin epoxide, lutein-5,6-epoxide, violaxanthin and neoxanthin) were isolated from a coriander ether extract using column chromatography and identified according to their chromatographic and spectral characteristics. No significant differences were noted with regard to their antioxidant properties using the ?-carotene\\/linoleic acid model, however they were inferior to the BHT and the crude etheric extract. The ?-carotene component represented

Nonete Barbosa Guerra; Enayde de Almeida Melo; Jorge Mancini Filho

2005-01-01

271

Diapause Prevention Effect of Bombyx mori by Dimethyl Sulfoxide  

PubMed Central

HCl treatment has been, for about 80 years, the primary method for the prevention of entry into embryonic diapauses of Bombyx mori. This is because no method is as effective as the HCl treatment. In this study, we discovered that dimethyl sulfoxide (DMSO) prevented entry into the diapause of the silkworm, Bombyx mori. The effect of diapause prevention was 78% as a result of treatment with 100% DMSO concentration, and the effect was comparable to that of the HCl treatment. In contrast, in the case of non-diapause eggs, hatchability was decreased by DMSO in a concentration-dependent manner. The effect of DMSO was restricted within 24 hours after oviposition of diapause eggs, and the critical period was slightly shorter than the effective period of the HCl treatment. DMSO analogs, such as dimethyl formamide (DMF) and dimethyl sulfide (DMS), did little preventive effect against the diapause. Furthermore, we also investigated the permeation effects of chemical compounds by DMSO. When treated with an inhibitor of protein kinase CK2 (CK2) dissolved in DMSO, the prevention rate of the diapause was less than 40%. This means that the inhibition effect by the CK2 inhibitor was the inhibition of embryonic development after diapause prevention by DMSO. These data suggest that DMSO has the effects of preventing from entering into the diapause and permeation of chemicals into diapause eggs. PMID:23675522

Yamamoto, Takayuki; Mase, Keisuke; Sawada, Hiroshi

2013-01-01

272

Diapause prevention effect of Bombyx mori by dimethyl sulfoxide.  

PubMed

HCl treatment has been, for about 80 years, the primary method for the prevention of entry into embryonic diapauses of Bombyx mori. This is because no method is as effective as the HCl treatment. In this study, we discovered that dimethyl sulfoxide (DMSO) prevented entry into the diapause of the silkworm, Bombyx mori. The effect of diapause prevention was 78% as a result of treatment with 100% DMSO concentration, and the effect was comparable to that of the HCl treatment. In contrast, in the case of non-diapause eggs, hatchability was decreased by DMSO in a concentration-dependent manner. The effect of DMSO was restricted within 24 hours after oviposition of diapause eggs, and the critical period was slightly shorter than the effective period of the HCl treatment. DMSO analogs, such as dimethyl formamide (DMF) and dimethyl sulfide (DMS), did little preventive effect against the diapause. Furthermore, we also investigated the permeation effects of chemical compounds by DMSO. When treated with an inhibitor of protein kinase CK2 (CK2) dissolved in DMSO, the prevention rate of the diapause was less than 40%. This means that the inhibition effect by the CK2 inhibitor was the inhibition of embryonic development after diapause prevention by DMSO. These data suggest that DMSO has the effects of preventing from entering into the diapause and permeation of chemicals into diapause eggs. PMID:23675522

Yamamoto, Takayuki; Mase, Keisuke; Sawada, Hiroshi

2013-01-01

273

Ultrasound assisted co-precipitation of nanostructured CuO-ZnO-Al2O3 over HZSM-5: effect of precursor and irradiation power on nanocatalyst properties and catalytic performance for direct syngas to DME.  

PubMed

Nanostructured CuO-ZnO-Al2O3/HZSM-5 was synthesized from nitrate and acetate precursors using ultrasound assisted co-precipitation method under different irradiation powers. The CuO-ZnO-Al2O3/HZSM-5 nanocatalysts were characterized using XRD, FESEM, BET, FTIR and EDX Dot-mapping analyses. The results indicated precursor type and irradiation power have significant influences on phase structure, morphology, surface area and functional groups. It was observed that the acetate formulated CuO-ZnO-Al2O3/HZSM-5 nanocatalyst have smaller CuO crystals with better dispersion and stronger interaction between components in comparison to nitrate based nanocatalysts. Ultrasound assisted co-precipitation synthesis method resulted in nanocatalyst with more uniform morphology compared to conventional method and increasing irradiation power yields smaller particles with better dispersion and higher surface area. Additionally the crystallinity of CuO is lower at high irradiation powers leading to stronger interaction between metal oxides. The nanocatalysts performance were tested at 200-300 °C, 10-40 bar and space velocity of 18,000-36,000 cm(3)/g h with the inlet gas composition of H2/CO = 2/1 in a stainless steel autoclave reactor. The acetate based nanocatalysts irradiated with higher levels of power exhibited better reactivity in terms of CO conversion and DME yield. While there is an optimal temperature for CO conversion and DME yield in direct synthesis of DME, CO conversion and DME yield both increase with the pressure increase. Furthermore ultrasound assisted co-precipitation method yields more stable CuO-ZnO-Al2O3/HZSM-5 nanocatalyst while conventional precipitated nanocatalyst lost their activity ca. 18% and 58% in terms of CO conversion and DME yield respectively in 24 h time on stream test. PMID:24409466

Allahyari, Somaiyeh; Haghighi, Mohammad; Ebadi, Amanollah; Hosseinzadeh, Shahin

2014-03-01

274

A gemini quaternary ammonium poly (ether ether ketone) anion-exchange membrane for alkaline fuel cell: design, synthesis, and properties.  

PubMed

To reconcile the tradeoff between conductivity and dimensional stability in AEMs, a novel Gemini quaternary ammonium poly (ether ether ketone) (GQ-PEEK) membrane was designed and successfully synthesized by a green three-step procedure that included polycondensation, bromination, and quaternization. Gemini quaternary ammonium cation groups attached to the anti-swelling PEEK backbone improved the ionic conductivity of the membranes while undergoing only moderate swelling. The grafting degree (GD) of the GQ-PEEK significantly affected the properties of the membranes, including their ion-exchange capacity, water uptake, swelling, and ionic conductivity. Our GQ-PEEK membranes exhibited less swelling (? 40?% at 25-70?°C, GD 67?%) and greater ionic conductivity (44.8?mS?cm(-1) at 75?°C, GD 67?%) compared with single quaternary ammonium poly (ether ether ketone). Enhanced fuel cell performance was achieved when the GQ-PEEK membranes were incorporated into H2 /O2 single cells. PMID:25346412

Si, Jiangju; Lu, Shanfu; Xu, Xin; Peng, Sikan; Xiu, Ruijie; Xiang, Yan

2014-12-01

275

Nonlinear relativity and the quantum ether  

SciTech Connect

The orthodox approach to relativistic quantum field theory axiomatically postulates Lorentz invariance, followed by the axioms of quantum mechanics. Departing from this approach we have designed a heuristic procedure by which the Lorentz transformations follow from the interactions characterized by the quantum mechanical commutation rules, rather than being postulated a priori. The most general operator representation of the quantum mechanical commutation rules that involve a length constant, have in the past been rejected on the ground that they violate Lorentz invariance. We therefore have applied our heuristic principle to derive the corresponding transformation equations that take into account the length constant appearing in this most general representation. We find a nonlinear generalization of the Lorentz transformations, departing from special relativity at very high energies and establishing the observable existence of a substratum (ether). The principle that the velocity of light is the same in all reference system still holds, but the theory gives a finite zero point vacuum energy. Furthermore, a non-Lorentz invariant behavior of cross sections at very high energy is predicted. In the limiting case where the length constant is set equal to zero, the zero point energy diverges and special relativity is recovered. The theory satisfies the philosophical principle by Leibniz, that the space-time structure should be determined from the interactions instead of being postulated a priori.

Winterberg, F.

1985-04-01

276

Tumour scanning with indium-111 dihaematoporphyrin ether.  

PubMed Central

Photofrin II (dihaematoporphyrin ether/ester, DHE) was labelled with indium-111 and its biodistribution in tumour bearing mice compared with that of 111In chloride. The uptake and clearance of 111In labelled DHE differed markedly from that of indium-111 chloride in that the former was not taken up by the tissues as much as the latter. Scintillation scanning with a gamma-camera showed marked uptake of both 111In agents at the site of the tumour, but a much lower tissue background (excluding the abdominal organs) for the mice given 111In DHE. Tumour:muscle ratios of dissected tissues were 2-3 times higher in 111In DHE treated animals as compared to the uptake of 111In chloride. There was a distinct difference in the pattern of distribution of the two 111In preparations in the tissues. The major accumulation of 111In chloride was in the kidneys, whereas the highest uptake of 111In DHE was in the liver, the organ in which unlabelled porphyrins accumulate. Extraction and testing of materials from tumours of 111In DHE treated animals indicated that most of the tumour extractable 111In had remained associated with the porphyrin in vivo up to 4 days after injection. Images Figure 1 PMID:2147858

Quastel, M. R.; Richter, A. M.; Levy, J. G.

1990-01-01

277

Nonlinear dielectric effect in supercritical diethyl ether  

NASA Astrophysics Data System (ADS)

Nonlinear dielectric effect (NDE) describes changes of dielectric permittivity induced by a strong electric field in a liquid dielectric. The most classical finding related to this magnitude is the negative sign of NDE in liquid diethyl ether (DEE), recalled by Peter Debye in his Nobel Prize lecture. This article shows that the positive sign of NDE in DEE is also possible, in the supercritical domain. Moreover, NDE on approaching the gas-liquid critical point exhibits a unique critical effect described by the critical exponent ? ? 0.4 close to critical temperature (TC) and ? ? 0.6 remote from TC. This can be linked to the emergence of the mean-field behavior in the immediate vicinity of TC, contrary to the typical pattern observed for critical phenomena. The multi-frequency mode of NDE measurements made it possible to estimate the evolution of lifetime of critical fluctuations. The new way of data analysis made it possible to describe the critical effect without a knowledge of the non-critical background contribution in prior.

Drozd-Rzoska, Aleksandra; Rzoska, Sylwester J.; Martinez-Garcia, Julio Cesar

2014-09-01

278

Sulfonated poly(ether ether ketone)\\/zirconium tricarboxybutylphosphonate composite proton-exchange membranes for direct methanol fuel cells  

Microsoft Academic Search

Sulfonated poly(ether ether ketone) (SPEEK) is a very promising alternative membrane material for direct methanol fuel cells.\\u000a However, with a fairly high degree of sulfonation (DS), SPEEK membranes can swell excessively and even dissolve at high temperature.\\u000a This restricts membranes from working above a high tolerable temperature to get high proton conductivity. To deal with this\\u000a contradictory situation, insolvable zirconium

Qijun Gao; Mianyan Huang; Yuxin Wang; Yuquan Cai; Li Xu

2008-01-01

279

Copoly(arlene ether)s containing pendant sulfonic acid groups as proton exchange membrane  

SciTech Connect

A copoly(arylene ether) (PAE) with high fluorine content and a copoly(arylene ether nitrile) (PAEN) with high nitrile content, each containing pendant phenyl sulfonic acids were synthesized. The P AE and PAEN were prepared from decafluorobiphenyl (DFBP) and difluorobenzonitrile (DFBN) respectively, by polycondensation with 2-phenylhydroquinone (PHQ) by conventional aromatic nucleophilic substitution reactions. The sulfonic acid groups were introduced by mild post-sulfonation exclusively on the para-position of the pendant phenyl ring in PHQ. The membrane properties of the resulting sulfonated copolymers sP AE and sP AEN were compared for fuel cell applications. The copolymers sPAE and sPAEN, each having a degree of sulfonation (DS) of 1.0 had high ion exchange capacities (IEC{sub v}(wet) (volume-based, wet state)) of 1.77 and 2.55 meq./cm{sup 3}, high proton conductivities of 135.4 and 140.1 mS/cm at 80 C, and acceptable volume-based water uptake of 44.5-51.9 vol% at 80 C, respectively, compared to Nafion. The data points of these copolymer membranes are located in the area of outstanding properties in the trade-off plot of alternative hydrocarbon polyelectrolyte membranes (PEM) for the relationship between proton conductivity versus water uptake (weight based or volume based). Furthermore, the relative selectivity derived from proton conductivity and methanol permeability is higher than that of Nafion.

Kim, Yu Seung [Los Alamos National Laboratory; Kim, Dae Sik [CANADA NRC; Robertson, Gilles [CANADA NRC; Guiver, Michael [CANADA NRC

2008-01-01

280

Surface orientation of hydrophilic groups in sulfonated poly(ether ether ketone) membranes.  

PubMed

Sulfonated poly(ether ether ketone) copolymers (SPEEK) with a range of sulfonate contents (SC 77-51%) were synthesized via nucleophilic substitution polycondensation from hydroquinone and sulfonated hydroquinone. Membranes obtained by solvent casting from dimethylacetamide onto glass surfaces were analyzed for surface behavior. The surfaces of a membrane were hydrophobic in air, but hydrophilic in water. This surface behavior was corroborated by water contact angle vs. time, using sessile drop measurements. Hydrophilic sulfonic group aggregates on SPEEK chain and various media contacting with the top or bottom surfaces of the membrane during the fabrication process caused differences in surface behavior. Angle-dependent XPS showed that there was a higher atomic S/C ratio of the bottom surface than on the corresponding top surface. The hydrophilic sulfonic groups were in higher concentration within the membrane, with the concentration gradually decreasing towards the surface for SPEEK-HQ-80 and SPEEK-HQ-70 membranes. Acidification with strong acid and higher temperature induced a more hydrophilic surface on a membrane than a milder acidification process. The depth profile at the membrane surface was examined by a combination of contact angle, XPS and ATR-FTIR. PMID:23978288

He, Chenfeng; Guiver, Michael D; Mighri, Frej; Kaliaguine, Serge

2013-11-01

281

Ethylene glycol monoethyl ether and ethylene glycol monoethyl ether acetate teratology studies  

SciTech Connect

An inhalation teratology study was conducted in rats at 10, 50 and 250 ppm ethylene glycol monoethyl ether (EGEE) and in rabbits at 10, 50, and 175 ppm EGEE. This study was designed to supplement a study conducted for NIOSH which showed teratogenic effects in rats at 200 ppm EGEE and in rabbits at about 160 ppm EE. In this study, EGEE was found not to cause teratogenic effects at concentrations up to and including 250 ppm in rats and 50 ppm in rabbits, while 175 ppm EGEE was considered to be a marginal effect level for teratogenic effects in rabbits. Fetotoxicity was observed at 250 ppm EGEE and possibly at 50 ppm EGEE in rats. An inhalation teratology study using ethylene glycol monoethyl ether acetate (EGEEA) has been conducted in rabbits at 25, 100, and 400 ppm. There was evidence of teratogenicity (vertebral malformations) at 400 ppm EGEEA and slight fetotoxicity at 100 ppm; 25 ppm was a no effect level. 12 references, 12 tables.

Doe, J.E.

1984-08-01

282

Vibrational spectroscopic study of pure and silica-doped sulfonated poly(ether ether ketone) membranes.  

PubMed

We report the vibrational properties of sulfonated poly(ether ether ketone) (SPEEK) membranes, used as electrolytes in proton exchange membrane (PEM) fuel cells, studied by Fourier transform infrared (FTIR) spectroscopy. We discuss the changes in the vibrational modes of the functional groups present in the polymer arising due to the sulfonation process and the subsequent incorporation of silica particles functionalized with sulfonic acid group. From the infrared spectra, we confirm the incorporation of sulfonic acid group in the polymer chain as well as in the functionalized silica particles. We have also measured the variations in the peak area ratio of the characteristic out-of-plane vibrations of the aromatic rings in the PEEK polymer at 1280cm(-1) with respect to a reference peak at 1305cm(-1). These values were correlated to the crystallinity (XC) values experimentally determined by DSC technique, providing a non-destructive means to calculate the crystallinity of polymer membranes. The calculated XC values were in good agreement with the experimental values. The crystallinity was observed to decrease with increasing degree of sulfonation (DS), indicating the crystalline-to-amorphous phase modification of the polymer by sulfonation, which along with the enhanced ion-exchange capacity and water uptake, is responsible for the improved ionic conductivity at higher DS values. PMID:25544185

Rangasamy, Vijay Shankar; Thayumanasundaram, Savitha; Seo, Jin Won; Locquet, Jean-Pierre

2015-03-01

283

Sulfonated poly(ether ether ketone)/amino-acid functionalized titania hybrid proton conductive membranes  

NASA Astrophysics Data System (ADS)

Inspired by the proton conducting mechanism in organisms where the amino acid groups play a crucial and multiple role, a novel kind of amino acid-functionalized titania submicrospheres was prepared and incorporated into sulfonated poly(ether ether ketone) (SPEEK) to fabricate the hybrid membranes for potential application in direct methanol fuel cells (DMFCs). The pristine titania submicrospheres (TiO2) with a uniform particle size of ?220 nm were synthesized via a sol-gel process and modified with amino acid groups through a facile chelation method. Meanwhile, amino groups, carboxylic groups and phenyl groups were introduced in the same way for comparison purpose. Compared with the control SPEEK membrane, the methanol crossover was reduced and the membrane mechanical strength was enhanced by incorporation of the functionalized titania submicrospheres. Due to the different proton acceptor/donor capability of the different functional groups, the hybrid membrane embedded with amino-functionalized titania exhibited lower proton conductivity at 20 °C but higher values at elevated temperature of 60 °C compared with carboxylic-functionalized titania; the hybrid membrane embedded with amino acid-functionalized titania displayed a superior proton-conducting ability with the highest proton conductivity of 0.258 S cm-1 at 60 °C.

Wu, Hong; Shen, Xiaohui; Xu, Tao; Hou, Weiqiang; Jiang, Zhongyi

2012-09-01

284

Molecular sieve/sulfonated poly(ether ketone ether sulfone) composite membrane as proton exchange membrane  

NASA Astrophysics Data System (ADS)

A proton exchange membrane (PEM) is an electrolyte membrane used in both polymer electrolyte membrane fuel cells (PEMFC) and direct methanol fuel cells (DMFCs). Currently, PEMs typically used for PEMFCs are mainly the commercially available Nafion^ membranes, which is high cost and loss of proton conductivity at elevated temperature. In this work, the Sulfonated poly(ether ketone ether sulfone), (S-PEKES), was synthesized by the nucleophilic aromatic substitution polycondensation between bisphenol S and 4,4'-dichlorobenzophenone, and followed by the sulfonation reaction with concentrated sulfuric acid. The molecular sieve was added in the S-PEKES matrix at various ratios to form composite membranes to be the candidate for PEM. Properties of both pure sulfonated polymer and composite membranes were compared with the commercial Nafion^ 117 membrane from Dupont. S-PEKES membranes cast from these materials were evaluated as a polymer electrolyte membrane for direct methanol fuel cells. The main properties investigated were the proton conductivity, methanol permeability, thermal, chemical, oxidative, and mechanical stabilities by using a LCR meter, Gas Chromatography, Thermogravimetric Analysis, Fourier Transform Infrared Spectroscopy, Fenton's reagent, and Universal Testing Machine. The addition of the molecular sieve helped to increase both the proton conductivity and the methanol stability. These composite membranes are shown as to be potential candidates for use as a Proton Exchange Membrane (PEM).

Changkhamchom, Sairung; Sirivat, Anuvat

2012-02-01

285

Poly(vinylbenzyl sulfonic acid)-grafted poly(ether ether ketone) membranes  

NASA Astrophysics Data System (ADS)

In this study, an aromatic hydrocarbon based polymer electrolyte membrane, poly(vinylbenzyl sulfonic acid)-grafted poly(ether ether ketone) (PEEK-g-PVBSA), has been prepared by the simultaneous irradiation grafting of vinylbenzyl chloride (VBC) monomer onto a PEEK film and subsequent sulfonation. Each chemical conversion was monitored by FT-IR and SEM-EDX instruments. The physicochemical properties including IEC, water uptake, proton conductivity, and methanol permeability of the prepared membranes were also investigated and found that the values of these properties increase with the increase of degree of grafting. It was observed that the IEC values of the prepared PEEK-g-PVBSA membranes with 32%, 58%, and 80% DOG values were 0.50, 1.05, and 1.22 meq/g while the water uptakes were 14%, 20%, and 21%, respectively. The proton conductivities (0.0272-0.0721 S/cm at 70 °C) were found to be somewhat lower than Nafion 212 (0.126 S/cm at 70 °C) at a relative humidity of 90%. However, the prepared membranes showed a considerably lower methanol permeability (0.61-1.92 × 10-7 cm2/s) compared to a Nafion 212 membrane (5.37 × 10-7 cm2/s).

Hwang, Mi-Lim; Choi, Jisun; Woo, Hyun-Su; Kumar, Vinod; Sohn, Joon-Yong; Shin, Junhwa

2014-02-01

286

Identification of hydroxylated polybrominated diphenyl ether metabolites in blood plasma from polybrominated diphenyl ether exposed rats.  

PubMed

Polybrominated diphenyl ethers (PBDEs) are ubiquitous environmental contaminants due to their use as flame retardants. Similarly to PCBs, the PBDEs are metabolized to hydroxylated metabolites (OH-PBDEs) in mammals. In the present study equimolar doses of seven environmentally relevant PBDE congeners were given intraperitoneally as a mixture to rats, and their blood plasma was analyzed for parent compounds and hydroxylated metabolites 1 and 5 days after dosing. Sixteen OH-PBDEs and two diOH-PBDEs were detected as PBDE metabolites in the rat plasma, a novel finding. Four OH-tetraBDEs were structurally identified by comparison (gas chromatography/mass spectrometry) with authentic reference standards. The position of the hydroxyl groups was suggested according to the mass spectrometric fragmentation patterns of the corresponding PBDE methyl ether derivatives. The OH-PBDE metabolites were dominated by hydroxyl groups in the meta- and parapositions. The results show that OH-PBDE congeners have an ability to be retained in rat blood, most likely by a mechanism similar to that of OH-PCBs. The results will be useful for determination of the origin of OH-PBDEs present in wildlife and in humans, since OH-PBDEs are also common natural products in marine environments. PMID:16082965

Malmberg, Tina; Athanasiadou, Maria; Marsh, Göran; Brandt, Ingvar; Bergman, Ake

2005-07-15

287

Reactivity of Cl-P(+)-Cl toward cyclic organic ethers.  

PubMed

The dichlorophosphenium ion (Cl-P(+)-Cl) undergoes a variety of reactions with cyclic organic ethers in the gas phase in a Fourier-transform ion cyclotron resonance mass spectrometer. Most of the reactions are initiated by Cl-P(+)-Cl-induced heterolytic C-O bond cleavage. However, the observed final products depend on the exact structure of the ether. For saturated ethers, e.g., tetrahydropyran, tetrahydrofuran, and 2-methyltetrahydrofuran, the most abundant ionic product corresponds to hydroxide abstraction by Cl-P(+)-Cl. This unexpected reaction is rationalized by a multistep mechanism that involves an initial heterolytic C-O bond cleavage accompanied by a 1,2-hydride shift, and that ultimately yields a resonance-stabilized allyl cation and HOPCl2. The process is estimated to be highly exothermic (AM1 calculations yield delta H = -(33-38) kcal mol(-1) for the ethers mentioned above). However, the adducts formed from most of the unsaturated ethers are unable to undergo hydride shifts and hence cannot react via this pathway. In some of these cases, e.g., for 2,5-dihydrofuran and 2,5-dihydro-3,4-benzofuran, the C-O bond heterolysis is followed by oxygen/chlorine exchange to yield the O=PCl radical and a resonance-stabilized carbocation (AM1 calculations yield delta H = -14 kcal mol(-1) for the reaction of 2,5-dihydro-3,4-benzofuran). Hydride abstraction by Cl-P(+)-Cl also yields an abundant product for these two ethers. On the other hand, the ethers with low ionization energies, such as 2,3-dihydrofuran and 2,3-dihydrobenzofuran, react with Cl-P(+)-Cl by electron transfer. Finally, a unique pathway, addition followed by elimination of HCl, dominates the reaction with furan. The observed reactions are rationalized by thermochemical data obtained from semiempirical molecular orbital calculations. PMID:10222594

Ramírez-Arizmendi, L E; Yu, Y Q; Kenttämaa, H I

1999-05-01

288

40 CFR 721.10174 - 1-Propanaminium, 3-amino-N-(carboxymethyl)-N,N-dimethyl-, N-peanut-oil acyl derivs., inner salts.  

Code of Federal Regulations, 2011 CFR

...carboxymethyl)-N,N-dimethyl-, N-peanut-oil acyl derivs., inner salts. ...carboxymethyl)-N,N-dimethyl-, N-peanut-oil acyl derivs., inner salts. ...carboxymethyl)-N,N-dimethyl-, N-peanut-oil acyl derivs., inner...

2011-07-01

289

40 CFR 721.10174 - 1-Propanaminium, 3-amino-N-(carboxymethyl)-N,N-dimethyl-, N-peanut-oil acyl derivs., inner salts.  

Code of Federal Regulations, 2013 CFR

...carboxymethyl)-N,N-dimethyl-, N-peanut-oil acyl derivs., inner salts. ...carboxymethyl)-N,N-dimethyl-, N-peanut-oil acyl derivs., inner salts. ...carboxymethyl)-N,N-dimethyl-, N-peanut-oil acyl derivs., inner...

2013-07-01

290

40 CFR 721.10174 - 1-Propanaminium, 3-amino-N-(carboxymethyl)-N,N-dimethyl-, N-peanut-oil acyl derivs., inner salts.  

Code of Federal Regulations, 2010 CFR

...carboxymethyl)-N,N-dimethyl-, N-peanut-oil acyl derivs., inner salts. ...carboxymethyl)-N,N-dimethyl-, N-peanut-oil acyl derivs., inner salts. ...carboxymethyl)-N,N-dimethyl-, N-peanut-oil acyl derivs., inner...

2010-07-01

291

40 CFR 721.10174 - 1-Propanaminium, 3-amino-N-(carboxymethyl)-N,N-dimethyl-, N-peanut-oil acyl derivs., inner salts.  

Code of Federal Regulations, 2014 CFR

...carboxymethyl)-N,N-dimethyl-, N-peanut-oil acyl derivs., inner salts. ...carboxymethyl)-N,N-dimethyl-, N-peanut-oil acyl derivs., inner salts. ...carboxymethyl)-N,N-dimethyl-, N-peanut-oil acyl derivs., inner...

2014-07-01

292

40 CFR 721.10174 - 1-Propanaminium, 3-amino-N-(carboxymethyl)-N,N-dimethyl-, N-peanut-oil acyl derivs., inner salts.  

Code of Federal Regulations, 2012 CFR

...carboxymethyl)-N,N-dimethyl-, N-peanut-oil acyl derivs., inner salts. ...carboxymethyl)-N,N-dimethyl-, N-peanut-oil acyl derivs., inner salts. ...carboxymethyl)-N,N-dimethyl-, N-peanut-oil acyl derivs., inner...

2012-07-01

293

40 CFR 721.2222 - Cyclohexanamine, N,N-dimethyl-, compd. with alpha-isotridecyl-omega-hydroxypoly(oxy-1,2...  

Code of Federal Regulations, 2010 CFR

...Cyclohexanamine, N,N-dimethyl-, compd. with alpha-isotridecyl-omega-hydroxypoly...Cyclohexanamine, N,N -dimethyl-, compd. with alpha-isotridecyl-omega-hydroxypoly...cyclohexanamine, N,N -dimethyl-, compd. with...

2010-07-01

294

40 CFR 721.10381 - Cyclic carboxylic acid, polymer with dihydroxy dialkyl ether, hydroxy substituted alkane and...  

Code of Federal Regulations, 2013 CFR

...dihydroxy dialkyl ether, hydroxy substituted alkane and carboxylic acid anhydride, methacrylate...dihydroxy dialkyl ether, hydroxy substituted alkane and carboxylic acid anhydride, methacrylate...dihydroxy dialkyl ether, hydroxy substituted alkane and carboxylic acid anhydride,...

2013-07-01

295

40 CFR 721.10381 - Cyclic carboxylic acid, polymer with dihydroxy dialkyl ether, hydroxy substituted alkane and...  

Code of Federal Regulations, 2012 CFR

...dihydroxy dialkyl ether, hydroxy substituted alkane and carboxylic acid anhydride, methacrylate...dihydroxy dialkyl ether, hydroxy substituted alkane and carboxylic acid anhydride, methacrylate...dihydroxy dialkyl ether, hydroxy substituted alkane and carboxylic acid anhydride,...

2012-07-01

296

40 CFR 721.10381 - Cyclic carboxylic acid, polymer with dihydroxy dialkyl ether, hydroxy substituted alkane and...  

Code of Federal Regulations, 2014 CFR

...dihydroxy dialkyl ether, hydroxy substituted alkane and carboxylic acid anhydride, methacrylate...dihydroxy dialkyl ether, hydroxy substituted alkane and carboxylic acid anhydride, methacrylate...dihydroxy dialkyl ether, hydroxy substituted alkane and carboxylic acid anhydride,...

2014-07-01

297

Low-energy electron interactions with dimethyl disulphide  

NASA Astrophysics Data System (ADS)

Electron attachment experiments have been performed with dimethyl disulphide, C2H6S2, in the gas phase by means of a crossed electron-molecular beam experiment. Ion yields for 8 anions have been measured in the energy range from ?0 to 15 eV. Many of the dissociative electron attachment products observed at low energy arise from surprisingly complex reactions associated with multiple bond cleavages as well as structural and electronic rearrangement. Quantum chemical calculations on the electronic properties of C2H6S2 have been performed in order to complement the experimental investigations.

Matias, C.; Mauracher, A.; Scheier, P.; Limão-Vieira, P.; Denifl, S.

2014-06-01

298

Bis(chlorido)(dimethyl­sulfoxide-?O)barium(II)  

PubMed Central

The title compound, [BaCl2(C2H6SO)], forms a Ba6Cl9 cluster in which the BaCl2 units are connected via dimethyl­sulfoxide (DMSO) and chloride bridges. The central Cl atom of the Ba6Cl9 cluster is located on a threefold inversion axis and is coordinated octa­hedrally to six barium cations. In the crystal, the clusters are arranged in rows, which are inter­connected by the DMSO mol­ecules, forming a three-dimensional network. PMID:23284316

Gschwind, Fabienne; Jansen, Martin

2012-01-01

299

Study of a Li-air battery having an electrolyte solution formed by a mixture of an ether-based aprotic solvent and an ionic liquid  

NASA Astrophysics Data System (ADS)

Recent studies have clearly demonstrated that cyclic and linear carbonates are unstable when used in rechargeable Li-air batteries employing aprotic solvents mostly due to the cathodic formation of superoxide during the oxygen reduction reaction. In particular, it has been ascertained that nucleophilic attack by superoxide anion radical, O2-rad , at O-alkyl carbon is a common mechanism of decomposition of organic carbonates. Moreover, theoretical calculations showed that ether chemical functionalities are stable against nucleophilic substitution induced by superoxide. Aim of this study is to report on a new electrolyte solution for Li-air battery formed by a mixture of an ether-based aprotic solvent with an ionic liquid (IL). The IL-based electrolyte was obtained by mixing the pure ionic liquid N-methyl-(n-butyl) pyrrolidinium bis(trifluoromethane sulfonyl) imide (here denoted as PYR14TFSI) to a 0.91 M solution of lithium triflate (LiCF3SO3) in tetra ethylene glycol dimethyl etcher (TEGDME). We observed that the presence of IL beneficially affects the kinetics and the reversibility of the oxygen reactions involved at the cathode. The most significant result being a lower overvoltage for the charge reaction, compared to a Li/air cell containing the same electrolyte solution without IL.

Cecchetto, Laura; Salomon, Mark; Scrosati, Bruno; Croce, Fausto

2012-09-01

300

Laboratory Method for Analysis of Small Concentrations of Methyl tert-Butyl Ether and Other Ether Gasoline Oxygenates in Water  

USGS Publications Warehouse

This Fact Sheet presents data for analysis of nanogram-per-liter concentrations of methyl tert-butyl ether (MTBE) and three other ether gasoline oxygenates, including methyl tert-pentyl ether (TAME), diisopropyl ether (DIPE), and ethyl tert-butyl ether (ETBE), by purge- and-trap capillary-column gas chromatography. Long-term method detection levels (LT-MDLs) for MTBE, TAME, DIPE, and ETBE ranged from 15 to 83 nanograms per liter (0.015 to 0.083 microgram per liter). Nanogram-per-liter-concentration detections are reported if all of the identification criteria are met, whereas previous methods censored detections at a pre-determined method reporting level. The reporting level for this method is defined as two times the LT-MDL, does not censor detections at less than this concentration, and is referred to as the nondetection value (NDV). Bias and variability data from multiple analyses, analysts, and instruments over a 60-day period show the oxygenate recoveries ranging from 100 to 109 percent, with 6 to 8 percent relative standard deviation. MTBE, TAME, DIPE, and ETBE were not detected in the analysis of 225 laboratory reagent blanks from January to December 1997. A preservation study in ground water and surface water indicates that all the oxygenates are stable at pH 2 for up to 216 days, with recoveries ranging from 94 to 115 percent on day 216, and relative standard deviations ranging from 5 to 9 percent for the duration of the study.

Rose, Donna L.; Connor, Brooke F.; Abney, Sonja R.; Raese, Jon W.

1998-01-01

301

Oxidative acetoxylation of the silyl ethers of ketone enols  

SciTech Connect

The authors studied the reaction of (dicarboxyiodo)benzenes with the trimethylsilyl ethers of ketone enols having various structures. They also undertook a comparative investigation of the oxidation of these compounds with lead tetraacetate. The reaction of (diacetoxyiodo)benzene with the trimethylsilyl ethers of ketone enols takes place with retention of the (CH/sub 3/)/sub 3/Si group in two directions, i.e., substitution of the vinylic hydrogen or diacetoxylation of the double bond. The reaction can be used for the regioselective synthesis of /alpha/-acetoxy ketones, since the trimethylsilyl group is readily eliminated from the obtained products by the action of fluoride ion or boron trifluoride etherate with the formation of the corresponding substituted ketones.

Brunovlenskaya, I.I.; Kusainova, K.M.; Kashin, A.K.

1988-07-20

302

Copoly(arylene ether)s containing pendant sulfonic acid groups as proton exchange membranes  

SciTech Connect

A copoly(arylene ether) (PAE) with high fluorine content and a copoly(arylene ether nitrile) (PAEN) with high nitrile content, each containing pendant phenyl sulfonic acids were synthesized. The PAE and P AEN were prepared from decafluorobiphenyl (DFBP) and difluorobenzonitrile (DFBN) respectively, by polycondensation with 2phenylhydroquinone (PHQ) by conventional aromatic nucleophilic substitution reactions. sulfonic acid groups were introduced by mild post-sulfonation exclusively on the para-position of the pendant phenyl ring in PHQ. The membrane properties of the resulting sulfonated copolymers sPAE and sPAEN were compared for fuel cell applications. The copolymers sPAE and sPAEN, each having a degree of sulfonation (OS) of 1.0 had high ion exchange capacities (IEC{sub v})(wet) (volume-based, wet state) of 1.77 and 2.55 meq./cm3, high proton conductivities of 135.4 and 140.1 mS/cm at 80 C, and acceptable volume-based water uptake of 44.5 -51.9 vol% at 80 C, respectively, compared to Nafion. The data points of these copolymer membranes are located in the upper left-hand corner in the trade-off plot of alternative hydrocarbon polyelectrolyte membranes (PEM) for the relationship between proton conductivity versus water uptake (weight based or volume based), i.e., high proton conductivity and low water uptake. Furthermore, the relative selectivity derived from proton conductivity and methanol permeability is higher than that of Nafion.

Dae Sik, Kim [Los Alamos National Laboratory; Yu Seung, Kim [Los Alamos National Laboratory; Gilles, Robertson [CANADA-NRC; Guiver, Michael D [CANADA-NRC

2009-01-01

303

Stress shielding and fatigue limits of poly-ether-ether-ketone dental implants.  

PubMed

The poly-ether-ether-ketone (PEEK) polymer is of great interest as an alternative to titanium in orthopedics because of its biocompatibility and low elastic modulus. This study evaluated the fatigue limits of PEEK and the effects of the low elastic modulus PEEK in relation to existing dental implants. Compressive loading tests were performed with glass fiber-reinforced PEEK (GFR-PEEK), carbon fiber-reinforced PEEK (CFR-PEEK), and titanium rods. Among these tests, GFR-PEEK fatigue tests were performed according to ISO 14801. For the finite element analysis, three-dimensional models of dental implants and bone were constructed. The implants in the test groups were coated with a 0.5-mm thick and 5-mm long PEEK layer on the upper intrabony area. The strain energy densities (SED) were calculated, and the bone resorption was predicted. The fatigue limits of GFR-PEEK were 310 N and were higher than the static compressive strength of GFR-PEEK. The bone around PEEK-coated implants showed higher levels of SED than the bone in direct contact with the implants, and the wider diameter and stiffer implants showed lower levels of SED. The compressive strength of the GFR-PEEK and CFR-PEEK implants ranged within the bite force of the anterior and posterior dentitions, respectively, and the PEEK implants showed adequate fatigue limits for replacing the anterior teeth. Dental implants with PEEK coatings and PEEK implants may reduce stress shielding effects. Dental implant application of PEEK polymer-fatigue limit and stress shielding. PMID:22331553

Lee, Woo-Taek; Koak, Jai-Young; Lim, Young-Jun; Kim, Seong-Kyun; Kwon, Ho-Beom; Kim, Myung-Joo

2012-05-01

304

Synthesis of , -Dimethylated Amino Acid Building Blocks Utilizing the 9-Phenylfluorenyl Protecting Group  

E-print Network

Synthesis of , -Dimethylated Amino Acid Building Blocks Utilizing the 9-Phenylfluorenyl Protecting pure , -dimethylated amino acid building blocks with functionalized side chains have been prepared from ester of the aspartate. As a result, the derivatives of the following novel amino acids were synthesized

Weisberg, Michael

305

DEVELOPMENTAL NEUOTOXICITY EVALUATION OF MIXTURES OF MONO- AND DIMETHYL TIN IN DRINKING WATER OF RATS.  

EPA Science Inventory

Developmental Neurotoxicity Evaluation of Mixtures of Mono- and Dimethyl Tin in Drinking Water of Rats V.C. Moser, K.L. McDaniel, P.M. Phillips Neurotoxicology Division, NHEERL, ORD, US EPA, RTP, NC, USA Organotins, especially monomethyl (MMT) and dimethyl (D...

306

CARCINOGENIC EVALUATION OF 2,3-DIMETHYL-2,3-DINITROBUTANE VIA THE MOUSE SKIN BIOASSAY  

EPA Science Inventory

Female SENCAR mice initiated with 2,3-dimethyl-2,3dimethyl-2,3-dinitrobutane (DMDNB) and promoted with 12-0-tetradecanoylphorol-13-acetate (TPA) via the SENCAR mouse skin bioassy did not exhibit a significant increase in skin tumors. The mice received 20 mg kg-1 DMDNE divided int...

307

Efficient and simple synthesis of 6-aryl-1,4-dimethyl-9H-carbazoles.  

PubMed

A synthetic method for the preparation of 6-aryl-1,4-dimethyl-9H-carbazoles involving a palladium catalyzed coupling reaction of 1,4-dimethyl-9H-carbazole-6-boronic acids and (hetero)aryl halides is described. PMID:18596657

Caruso, Anna; Voisin-Chiret, Anne Sophie; Lancelot, Jean-Charles; Sinicropi, Maria Stefania; Garofalo, Antonio; Rault, Sylvain

2008-01-01

308

Facile Oxidative Cleavage of 4-O-Benzyl Ethers with Dichlorodicyanoquinone in Rhamno and Mannopyranosides  

PubMed Central

On exposure to dichlorodicyanoquinone in wet dichloromethane at room temperature equatorial 4-O-benzyl ethers are removed with moderate selectivity in the presence of other benzyl ethers in glycopyranosides and glycothiopyranosides. PMID:17375956

Vinogradova, Olga

2008-01-01

309

DOI: 10.1002/adsc.200700546 Iridium-Catalyzed Asymmetric Hydrogenation of Vinyl Ethers  

E-print Network

DOI: 10.1002/adsc.200700546 Iridium-Catalyzed Asymmetric Hydrogenation of Vinyl Ethers Ye Zhua,P-ligated iridium complexes in asymmetric hydrogenations of the silyl and methyl enol ethers D and E, but complex

Burgess, Kevin

310

46 CFR 151.50-40 - Additional requirements for carbon disulfide (carbon bisulfide) and ethyl ether.  

Code of Federal Regulations, 2010 CFR

... Additional requirements for carbon disulfide (carbon bisulfide) and ethyl ether... Additional requirements for carbon disulfide (carbon bisulfide) and ethyl ether...requirements of § 151.50-41 for carbon disulfide (carbon bisulfide ) and §...

2010-10-01

311

Supramolecular polymers constructed by crown ether-based molecular recognition.  

PubMed

Supramolecular polymers, polymeric systems beyond the molecule, have attracted more and more attention from scientists due to their applications in various fields, including stimuli-responsive materials, healable materials, and drug delivery. Due to their good selectivity and convenient enviro-responsiveness, crown ether-based molecular recognition motifs have been actively employed to fabricate supramolecular polymers with interesting properties and novel applications in recent years. In this tutorial review, we classify supramolecular polymers based on their differences in topology and cover recent advances in the marriage between crown ether-based molecular recognition and polymer science. PMID:22012256

Zheng, Bo; Wang, Feng; Dong, Shengyi; Huang, Feihe

2012-03-01

312

Triple ring closing metathesis reaction: synthesis of adjacent cyclic ethers.  

PubMed

[reaction: see text] Adjacent tris(cyclic ethers) and enol ethers have been synthesized in good yields for the first time via a triple olefin metathesis reaction using Grubbs' catalyst RuCl(2)(=C(H)Ph)(PCy(3))(2) (Cy = cyclohexyl), and the 1,3-dimesitylimidazol-2-ylidene ruthenium benzylidene catalyst RuCl(2)(=C(H)Ph)(PCy(3))(IMes) ((IMes) = 1,3-bis(2,4,6-trimethylphenyl)imidazol-2-ylidene). The latter proved to be the most efficient catalyst in these transformations. PMID:11418031

Heck, M P; Baylon, C; Nolan, S P; Mioskowski, C

2001-06-28

313

Densities and Viscosities of Binary Mixtures of Methanol with Dimethyl Methylphosphonate and Dimethyl Phosphite from (293.15 to 333.15) K  

NASA Astrophysics Data System (ADS)

Densities and viscosities of methanol + dimethyl methylphosphonate and methanol + dimethyl phosphite binary mixtures were measured over a temperature range of (293.15 to 333.15) K at atmospheric pressure. The experimental data were compared with literature values. From these data, excess molar volumes ( V E) were calculated. The density data were fitted to a second-order polynomial, and the viscosity data were fitted to the Andrade equation.

Wang, Li-Sheng; Tian, Na-Na

2011-06-01

314

Degradation of dimethyl disulfide using homogeneous Fenton's reaction.  

PubMed

In this work the degradation of a model odor compound (dimethyl disulfide, DMDS) using Fenton's reaction is reported. Dimethyl disulfide is present in wastewaters generated during production of poultry feather and viscera meal. Oxidation was carried out in batch reactor with temperature control. Experimental design technique was used to investigate the influence of concentration of hydrogen peroxide and Fe(2+), temperature and pH on degradation of DMDS. Control reactions using H(2)O(2) without Fe(2+) were carried out, but DMDS degradation could only reach 60% for a 0.025 mg L(-1) DMDS solution, at pH 3, 60 degrees C using 10,000 mg L(-1) H(2)O(2) in 30 min of reaction. The Fenton's reaction could effectively remove DMDS, reaching 95% degradation at pH 3, 60 degrees C, 5 mg L(-1) H(2)O(2) and 1 mg L(-1) Fe(2+) after only 10 min of contact. A kinetic study of the Fenton's reaction was carried out, varying the concentration of hydrogen peroxide, Fe(2+) and temperature. PMID:19395163

Krüger, Roberta Letícia; Dallago, Rogério Marcos; Di Luccio, Marco

2009-09-30

315

Lithium solvation in dimethyl sulfoxide-acetonitrile mixtures  

NASA Astrophysics Data System (ADS)

We present molecular dynamics simulation results pertaining to the solvation of Li+ in dimethyl sulfoxide-acetonitrile binary mixtures. The results are potentially relevant in the design of Li-air batteries that rely on aprotic mixtures as solvent media. To analyze effects derived from differences in ionic size and charge sign, the solvation of Li+ is compared to the ones observed for infinitely diluted K+ and Cl- species, in similar solutions. At all compositions, the cations are preferentially solvated by dimethyl sulfoxide. Contrasting, the first solvation shell of Cl- shows a gradual modification in its composition, which varies linearly with the global concentrations of the two solvents in the mixtures. Moreover, the energetics of the solvation, described in terms of the corresponding solute-solvent coupling, presents a clear non-ideal concentration dependence. Similar nonlinear trends were found for the stabilization of different ionic species in solution, compared to the ones exhibited by their electrically neutral counterparts. These tendencies account for the characteristics of the free energy associated to the stabilization of Li+Cl-, contact-ion-pairs in these solutions. Ionic transport is also analyzed. Dynamical results show concentration trends similar to those recently obtained from direct experimental measurements.

Semino, Rocío; Zaldívar, Gervasio; Calvo, Ernesto J.; Laria, Daniel

2014-12-01

316

High octane ethers from synthesis gas-derived alcohols. Technical progress report, October--December 1991  

SciTech Connect

The objective of the proposed research is to synthesize high octane ethers, primarily methyl isobutyl ether (MIBE) and methyl tertiary butyl ether (MTBE), directly from H{sub 2}/CO/CO{sub 2} coal-derived synthesis gas via alcohol mixtures that are rich in methanol and 2-methyl-1-propanol (isobutanol). The overall scheme involves gasification of coal, purification and shifting of the synthesis gas, higher alcohol synthesis, and direct synthesis of ethers.

Klier, K.; Herman, R.G.; Johansson, M.; Feeley, O.C.

1992-01-01

317

Chemistry and catalysis of coal liquefaction; catalytic and thermal upgrading of coal liquids; and hydrogenation of CO to produce fuels. Volume VI. Final report. [Dibenzyl ether  

Microsoft Academic Search

This work was concerned with a study of hydropyrolysis reactions of three selected ethers, i.e., dibenzyl ether, phenyl methyl ether (anisole), and diphenyl ether, which are representative of etheric types present in coal-derived liquids. The purpose was to determine the relative susceptibility of such ethers to noncatalytic (thermal) hydrooxygenation (HDO), and thereby evaluate the feasibility of applying hydropyrolysis as an

1985-01-01

318

Kinetics of Protonation of Li+, Na+ and K+ Salts of Anthracenide Radical Ions in DME and THF by Methanol and tert-Butanol; The Significant Contribution of the Encounter Complex to the Protonation  

Microsoft Academic Search

Kinetics of protonation of Li+, Na+, and K+ salts of anthracenide radical ions (A{\\\\cdot}) by methanol (MeOH) and tert-butanol (tert-BuOH) in dimethoxyethane (DME) and tetrahydrofuran (THF) was studied by a stop-flow technique. Radical ions (A{\\\\cdot}, Cat+) and the salts of anthracene dianions (A2-, 2Cat+) formed by disproportionation of radical anions, are the protonated bases; the protonation of the first species

A. Rainis; R. Tung; M. Szwarc

1974-01-01

319

40 CFR 721.7000 - Polymer of disodium maleate, allyl ether, and ethylene oxide.  

Code of Federal Regulations, 2012 CFR

...disodium maleate, allyl ether, and ethylene oxide. 721.7000 Section 721.7000 ...disodium maleate, allyl ether, and ethylene oxide. (a) Chemical substance and significant...disodium maleate, allyl ether, and ethylene oxide (P-91-1086) is subject to...

2012-07-01

320

Proposed Occupational Exposure Limits for Select Ethylene Glycol Ethers Using PBPK Models and Monte Carlo Simulations  

Microsoft Academic Search

Methoxyethanol (ethylene glycol monomethyl ether, EGME), ethoxyethanol (ethylene glycol monoethyl ether, EGEE), and ethoxyethyl acetate (ethylene glycol monoethyl ether acetate, EGEEA) are all developmental toxicants in laboratory animals. Due to the imprecise nature of the exposure data in epidemiology studies of these chemicals, we relied on human and animal phar- macokinetic data, as well as animal toxicity data, to derive

L. M. Sweeney; J. F. Holson; M. D. Whorton; K. M. Thompson; M. L. Gargas

321

A homoleptic uranium thiolate: Synthesis, structure, and fluxional behavior of (Li(dme)) sub 4 (U(SCH sub 2 CH sub 2 S) sub 4 ) and reaction with CS sub 2  

SciTech Connect

We have synthesized and fully characterized a tetrakis(ethane-1,2-dithiolato)uranate(IV), (Li(dme)){sub 4}(U(edt){sub 4}) (1), the first homoleptic dithiolate complex of an f element. The complex crystallizes with an additional DME solvent molecule, and its structure was determined by an x-ray study. The coordination geometry about the uranium center is dodecahedral, and four lithium cations surround the (U(edt){sub 4}){sup 4{minus}} anion. Each lithium bridges two sulfur atoms and is further coordinated by a dme molecule. We have analyzed the nature of the U-S bonds, using the extended Hueckel method, to find that U 6d, 7s, and 7p orbitals are responsible for interactions with sulfur orbitals, thus, no significant U 5f participation in bonding is discernible, and that U-S {pi} interactions are weak. The low temperature {sup 1}H NMR spectra in the THF-d{sub 8} exhibit four resonances associated with the edt protons. The relative size of their paramagnetic isotropic shifts can be interpreted on the basis of the pseudocontact (dipolar) term, the analysis of which suggests the solid-state dodecahedral structure to be retained in solution. The thermodynamic properties and crystal structure of the complex was determined, and they are reported herein. 53 refs., 5 figs., 8 tabs.

Tatsumi, Kazuyuki; Matsubara, Ichiro; Inoue, Yoshihisa; Nakamura, Akira (Osaka Univ. (Japan)); Cramer, R.E.; Tagoshi, G.J.; Golen, J.A.; Gilje, J.W. (Univ. of Hawaii, Honolulu (USA))

1990-11-28

322

Synthesis and characterization of fluorinated crosslinkable poly(phthalazinone ether)s bearing tetrafluorostyrene groups for optical waveguides  

Microsoft Academic Search

A series of novel fluorinated crosslinkable poly(phthalazinone ether)s bearing tetrafluorostyrene groups (FSt-FPPEs) was prepared by polycondensation from 4-(4?-hydroxyphenyl)-phthalazin-1(2 H)-one (DHPZ), decafluorobiphenyl, 4,4-(hexafluoroisopropylidene)diphenol (6F-BPA) and pentafluorostyrene (FSt) for optical waveguide applications. The obtained polymers exhibited good solubility in common organic solvents and could be easily cast into optical-quality thin films. The resulting polymers could be thermally crosslinked either at 160 °C

Guanghui Li; Jinyan Wang; Su Guixian; Xigao Jian; Linghua Wang; Mingshan Zhao

2010-01-01

323

Sulfonated poly(ether ether ketone) membranes containing pendent carboxylic acid groups and their application in vanadium flow battery  

NASA Astrophysics Data System (ADS)

Sulfonated poly(ether ether ketone) (C-SPEEK) membranes with pendent carboxylic acid groups are prepared and first investigated for vanadium flow battery (VFB) application. The introduction of carboxylic acid groups can effectively improve the ion conductivities of C-SPEEK membranes, while, keep their ion selectivities. The prepared C-SPEEK membranes exhibit excellent performance under VFB operating condition. VFB single cell assembled with C-SPEEK-50 membranes shows much higher energy efficiency (85% Vs 82%) and columbic efficiency (97.3% Vs 94.6%) than that assembled with Nafion 115. The membrane keeps a stable performance after more than 180 cycles charge-discharge test, showing good stability.

Chen, Dongju; Li, Xianfeng

2014-02-01

324

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

PubMed

Nine bacterial strains isolated from two hydrocarbon-contaminated soils were selected because of their capacity for growth in culture media amended with 200 mg/L of one of the following gasoline oxygenates: Methyl-tert-butyl ether (MTBE), ethyl-tert-butyl ether (ETBE), and tert-amyl methyl ether (TAME). These strains were identified by amplification of their 16S rRNA gene, using fDl and rD1 primers, and were tested for their capacity to grow and biotransform these oxygenates in both mineral and cometabolic media. The isolates were classified as Bacillus simplex, Bacillus drentensis, Arthrobacter sp., Acinetobacter calcoaceticus, Acinetobacter sp., Gordonia amicalis (two strains), Nocardioides sp., and Rhodococcus ruber. Arthrobacter sp. (strain MG) and A. calcoaceticus (strain M10) consumed 100 (cometabolic medium) and 82 mg/L (mineral medium) of oxygenate TAME in 21 d, respectively, under aerobic conditions. Rhodococcus ruber (strain E10) was observed to use MTBE and ETBE as the sole carbon and energy source, whereas G. amicalis (strain T3) used TAME as the sole carbon and energy source for growth. All the bacterial strains transformed oxygenates better in the presence of an alternative carbon source (ethanol) with the exception of A. calcoaceticus (strain M10). The capacity of the selected strains to remove MTBE, ETBE, and TAME looks promising for application in bioremediation technologies. PMID:18522454

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

2008-11-01

325

Radiation chemistry of alternative fuel oxygenates -- Substituted ethers  

SciTech Connect

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).

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

1999-11-15

326

AVOIDING HYDROLYSIS OF FUEL ETHER OXYGENATES DURING STATIC HEADSPACE ANALYSIS  

EPA Science Inventory

A headspace autosampler, gas chromatograph and ion trap mass spectrometer (headspace GC/MS) were used for trace analysis of fuel oxygenates and related compounds and aromatics in water. A method has been developed for determination of methyl tert-butyl ether (MTBE), ethyl tert-b...

327

Polybrominated Diphenyl Ethers in the Sediments of the Great Lakes.  

E-print Network

Polybrominated Diphenyl Ethers in the Sediments of the Great Lakes. 3. Lakes Ontario and Erie W E N project has been conducted to assess the extent of PBDE pollution to the Laurentian Great Lakes area and volume, respectively, among the five Great Lakes. The water in these two lakes has much

Rockne, Karl J.

328

Polybrominated Diphenyl Ethers in the Sediments of the Great Lakes.  

E-print Network

Polybrominated Diphenyl Ethers in the Sediments of the Great Lakes. 1. Lake Superior W E N L U S O, blood, and adipose tissues (7). In the Great Lakes region, the concentration of PBDEs in the air at four found in the fish of all the five Great Lakes (9-11). Atmospheric deposition has proven to be a major

Rockne, Karl J.

329

Tea saponin enhanced biodegradation of decabromodiphenyl ether by Brevibacillus brevis.  

PubMed

Decabromodiphenyl ether (BDE209) is a ubiquitous persistent pollutant and has contaminated the environment worldwide. To accelerate BDE209 elimination and reveal the mechanism concerned, the biosurfactant tea saponin enhanced degradation of BDE209 by Brevibacillus brevis was conducted. The results revealed that tea saponin could efficiently increase the solubility of BDE209 in mineral salts medium and improve its biodegradation. The degradation efficiency of 0.5 mg L(-1) BDE209 by 1 g L(-1) biomass with surfactant was up to 55% within 5d. Contact time was a significant factor for BDE209 biodegradation. BDE209 biodegradation was coupled with bioaccumulation, ion release and utilization, and debromination to lower brominated PBDE metabolites. During the biodegradation process, B. brevis metabolically released Na(+), NH4(+), NO2(-) and Cl(-), and utilized the nutrient ions Mg(2+), PO4(3-) and SO4(2-). GC-MS analysis revealed that the structure of BDE209 changed under the action of strain and nonabromodiphenyl ethers (BDE-208, -207 and -206), octabromodiphenyl ethers (BDE-203, -197 and -196) and heptabromodiphenyl ether (BDE-183) were generated by debromination. PMID:25113210

Tang, Shaoyu; Bai, Jieqiong; Yin, Hua; Ye, Jinshao; Peng, Hui; Liu, Zehua; Dang, Zhi

2014-11-01

330

Synthesis of hydroxytyrosyl alkyl ethers from olive oil waste waters.  

PubMed

The preparation of a new type of derivatives of the naturally occurring antioxidant hydroxytyrosol is reported. Hydroxytyrosyl alkyl ethers were obtained in high yield by a three-step procedure starting from hydroxytyrosol isolated from olive oil waste waters. Preliminary results obtained by the Rancimat method have shown that these derivatives retain the high protective capacity of free hydroxytyrosol. PMID:19471196

Madrona, Andrés; Pereira-Caro, Gema; Mateos, Raquel; Rodríguez, Guillermo; Trujillo, Mariana; Fernández-Bolaños, Juan; Espartero, José L

2009-01-01

331

Polybrominated Diphenyl Ethers in Maternal and Fetal Blood Samples  

Microsoft Academic Search

Polybrominated diphenyl ethers (PBDEs) are widely used as flame retardants in consumer goods, such as plastics, electronics, textiles, and construction material. PBDEs have been found in human milk, fat, and blood samples. Rodent studies indicate that PBDEs may be detrimental to neuro- development, possibly by lowering thyroid hormone concentrations in blood. In the present study, we determined concentrations of PBDEs

Anita Mazdai; Nathan G. Dodder; Mary Pell Abernathy; Ronald A. Hites; Robert M. Bigsby

2003-01-01

332

Structure-property study of keto-ether polyimides  

NASA Technical Reports Server (NTRS)

As part of an on-going effort to develop an understanding of how changes in the chemical structure affect polymer properties, an empirical study was performed on polyimides containing only ether and/or carbonyl connecting groups in the polymer backbone. During the past two decades the structure-property relationships in linear aromatic polyimides have been extensively investigated. More recently, work has been performed to study the effect of isomeric attachment of keto-ether polyimides on properties such as glass transition temperature and solubility. However, little work has been reported on the relation of polyimide structure to mechanical properties. The purpose of this study was to determine the effect of structural changes in the backbone of keto-ether polyimides on their mechanical properties, specifically, unoriented thin film tensile properties. This study was conducted in two stages. The purpose of the initial stage was to examine the physical and mechanical properties of a representative group (four) of polyimide systems to determine the optimum solvent and cure cycle requirements. These optimum conditions were then utilized in the second stage to prepare films of keto-ether polyimides which were evaluated for mechanical and physical properties. All of the polyimides were prepared using isomers of oxydianiline (ODA) and diaminobenzophenone (DABP) in combination with 3,3',4,4'-benzophenonetetracarboxylic dianhydride (BTDA) and 4,4'-oxydiphthalic anhydride (ODPA).

Dezern, James F.; Croall, Catharine I.

1991-01-01

333

IRIS Toxicological Review of Pentabromodiphenyl Ether (Final Report)  

EPA Science Inventory

The purpose of this Toxicological Review is to provide scientific support and rationale for the hazard and dose-response assessment in IRIS pertaining to chronic exposure to 2,2',4,4',5-pentabromodiphenyl ether. It is not intended to be a comprehensive treatise on the chemical...

334

Synthesis and antitubercular activity of heterocycle substituted diphenyl ether derivatives  

Technology Transfer Automated Retrieval System (TEKTRAN)

Despite being an ancient disease, tuberculosis (TB) remains the leading single-agent infectious disease killer in the world. The emerging serious problem due to TB control and clinical management prompted us to synthesize novel series of heterocyclic substituted diphenyl ether derivatives and determ...

335

Effect of Parameters on Oxychlorination of Tert-Butyl Ethers  

PubMed Central

The effect of concentration, molar ratios of reagents, pH, and temperature on formation of chloro-organic products in reaction of tert-butyl ethers with chloride ions and hydrogen peroxide has been determined. A significant effect of Cl? ions and H2O2 molar ratios on the rate of chloro-organic product formation has been observed. Studies on oxychlorination of tert-butylethyl ether (ETBE) at pH 7, 3.5, and 2.5 have been carried out. It was found that introduction of hydronium ions into the reaction system considerably hastened the process of chloro-organic product formation. Hydronium ions contribute to the formation of the reactive tert-butyl carbocation, which undergoes secondary reactions in the presence of reactive forms of chlorine and oxygen. Moreover, the effect of temperature on ETBE (tert-butylethyl ether) and MTBE (tert-butylmethyl ether) conversions was verified. The reactions of MTBE and ETBE oxychlorination were carried out at temperatures of 5°C, 20°C, and 35°C. PMID:19696944

Gaca, Jerzy; Gackowska, Alicja; Belt, Natalia

2008-01-01

336

Effect of Parameters on Oxychlorination of Tert-Butyl Ethers.  

PubMed

The effect of concentration, molar ratios of reagents, pH, and temperature on formation of chloro-organic products in reaction of tert-butyl ethers with chloride ions and hydrogen peroxide has been determined. A significant effect of Cl(-) ions and H(2)O(2) molar ratios on the rate of chloro-organic product formation has been observed. Studies on oxychlorination of tert-butylethyl ether (ETBE) at pH 7, 3.5, and 2.5 have been carried out. It was found that introduction of hydronium ions into the reaction system considerably hastened the process of chloro-organic product formation. Hydronium ions contribute to the formation of the reactive tert-butyl carbocation, which undergoes secondary reactions in the presence of reactive forms of chlorine and oxygen. Moreover, the effect of temperature on ETBE (tert-butylethyl ether) and MTBE (tert-butylmethyl ether) conversions was verified. The reactions of MTBE and ETBE oxychlorination were carried out at temperatures of 5 degrees C, 20 degrees C, and 35 degrees C. PMID:19696944

Gaca, Jerzy; Gackowska, Alicja; Belt, Natalia

2008-07-01

337

FLUORINATED ETHERS--A NEW FAMILY OF HALONS?  

EPA Science Inventory

The paper discusses the possiblity of fluorinated ethers' being a new family of halons. or at the University of Tennessee to find suitable replacements for fully halogenated chlorofluorocarbons (CFCs) and halons has centered on the incorporation of oxygen as a heteroatom. he most...

338

Developmental neurotoxicity of polybrominated diphenyl ether (PBDE) flame retardants  

Microsoft Academic Search

Polybrominated diphenyl ethers (PBDEs) are a class of flame retardants used in a variety of consumer products. In the past 25 years, PBDEs have become ubiquitous environmental contaminants. They have been detected in soil, air, sediments, birds, marine species, fish, house dust, and human tissues, blood and breast milk. Diet and house dust appear to be the major sources of

Lucio G. Costa; Gennaro Giordano

2007-01-01

339

Polybrominated diphenyl ether flame retardants in the North American environment  

Microsoft Academic Search

North America consumes over half of the world's production of polybrominated diphenyl ether (PBDE) flame retardants. About 98% of global demand for the Penta-BDE mixture, the constituents of which are the most bioaccumulative and environmentally widespread, resides here. However, research on the environmental distribution of PBDEs in North America has lagged behind that in Northern Europe. Examination of available governmentally

Robert C. Hale; Mehran Alaee; Jon B. Manchester-Neesvig; Heather M. Stapleton; Michael G. Ikonomou

2003-01-01

340

Is decabromodiphenyl ether (BDE209) a developmental neurotoxicant?  

Microsoft Academic Search

Polybrominated diphenyl ether (PBDE) flame retardants have become ubiquitous environmental pollutants. The relatively higher body burden in toddlers and children has raised concern for their potential developmental neurotoxicity, which has been suggested by animal studies, in vitro experiments, and recent human epidemiological evidence. While lower brominated PBDEs have been banned in several countries, the fully brominated decaBDE (BDE-209) is still

Lucio G. Costa; Gennaro Giordano

2011-01-01

341

An Exposure Assessment of Industries using Ethylene Glycol Ethers  

Microsoft Academic Search

Human case reports and animal experiments have shown that ethylene glycol ethers have the potential to cause adverse health effects. The National Institute for Occupational Safety and Health has completed an exposure assessment of industries to determine the extent of occupational exposure to 2-methoxyethanol, 2-ethoxyethanol, and their respective acetates (2-methoxyethyl acetate and 2-ethoxyethyl acetate). This information is useful for assessing

Greg M. Piacitelli; David M. Votaw; E. Radha Krishnan

1990-01-01

342

Metal-Catalyzed Cascade Rearrangements of 3-Alkynyl Flavone Ethers  

PubMed Central

Metal-mediated rearrangements of 3-alkynyl flavone ethers are reported. The overall process involves 5-endo enynecyclization to a platinum-containing spiro-oxocarbenium intermediate which may be trapped with methanol to produce spirodihydrofurans or further rearranged to afford either allenyl chromanediones or benzofuranones. PMID:23574045

Xiong, Yuan; Schaus, Scott E.

2013-01-01

343

A potassium crown ether complex with dichloroaurate(I)  

E-print Network

The title compound, (1,4,7,10,13,16-hexaoxa­cyclo­octane)­potassium di­chloro­aurate(I), [K(C12H24O6)][AuCl2], consists of potassium ion encapsulated by the 18-membered crown ether 1,4,7,10,13,16-hexaoxa­cyclo­octane and a linear di...

Hossain, Alamgir; Powell, Douglas R.; Bowman-James, Kristin

2003-01-17

344

Antiknock evaluation of hydrocarbons and ethers as aviation fuel components  

NASA Technical Reports Server (NTRS)

The results of a NACA investigation conducted over a period of several years to evaluate the anti-knock characteristics of organic compounds are summarized. Included are data for 18 branched paraffins and olefins, 27 aromatics, and 22 ethers. The factors of performance investigated were blending characteristics, temperature sensitivity, lead response, and relation between molecular structure and antiknock ratings. Four engines were used.

Barnett, Henry C

1950-01-01

345

DEVELOPMENT OF SENSITIVE MAGNETIC PARTICLE IMMUNOASSAY FOR POLYBROMINATED DIPHENYL ETHERS.  

Technology Transfer Automated Retrieval System (TEKTRAN)

A sensitive magnetic particle based immunoassay for polybrominated diphenyl ether (PBDE) was developed. Rabbit antiserum was produced by immunizing the rabbit with 4-(2,4-dibromo-5-(2,4-dibromophenoxy)phenoxy)butyrate-BSA. The PBDE ligand and horse radish peroxidase were conjugated via NHS and EDA...

346

45. BUILDING NO. 519, ETHER AND ALCOHOL RECOVERY HOUSE, INTERIOR, ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

45. BUILDING NO. 519, ETHER AND ALCOHOL RECOVERY HOUSE, INTERIOR, CONTROL PANEL LEVEL (2ND DECK), LOOKING AT 'MIXED SOLVENT UNIT' CONTROL PANEL (LOOKING EAST). - Picatinny Arsenal, 500 Area, Powder Factory & Power House, State Route 15 near I-80, Dover, Morris County, NJ

347

43. BUILDING NO. 519, ETHER AND ALCOHOL RECOVERY HOUSE, INTERIOR, ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

43. BUILDING NO. 519, ETHER AND ALCOHOL RECOVERY HOUSE, INTERIOR, NORTH WING, 1ST LEVEL, LOOKING SOUTHWEST AT EQUIPMENT USED TO CONDENSE SOLVENT VAPORS TRANSMITTED BY SOLVENT RECOVERY DUCT FROM BUILDING NO. 527. - Picatinny Arsenal, 500 Area, Powder Factory & Power House, State Route 15 near I-80, Dover, Morris County, NJ

348

42. BUILDING NO. 519, ETHER AND ALCOHOL RECOVERY HOUSE, INTERIOR, ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

42. BUILDING NO. 519, ETHER AND ALCOHOL RECOVERY HOUSE, INTERIOR, NORTH WING, 1ST LEVEL, VIEW OF FILTERS AND BLOWERS FOR SOLVENT VAPORS FROM BUILDING NO. 527. - Picatinny Arsenal, 500 Area, Powder Factory & Power House, State Route 15 near I-80, Dover, Morris County, NJ

349

Aerobic biotransformation of decabromodiphenyl ether (PBDE-209) by Pseudomonas aeruginosa.  

PubMed

Aerobic biodegradation of decabromodiphenyl ether (PBDE-209) by Pseudomonas aeruginosa under the influence of co-metabolic substrates and heavy metal cadmium ion was studied, The results showed that certain amount of co-metabolic substrates, such as glucose, sucrose, lactose, starch, and beef extract, would promote the biodegradation of PBDE-209, among which glucose most favorably accelerated PBDE-209 degradation by about 36% within 5d. The highest degradation efficiency was reached at the ratio of PBDE-209 and glucose 1:5 while excessive carbon source would actually hamper the degradation efficiency. Exploration of influences of cadmium ion on PBDE-209 biodegradation indicated that degradation efficiency was stimulated at low concentrations of Cd(2+) (0.5-2 mg L(-1)) while inhibited at higher levels (5-10 mg L(-1)), inferring that the heavy metals of different concentrations possessed mixed reactions on PBDE-209 bioremoval. Bromine ion was produced during the biotransformation process and its concentration had a good negative correlation with the residues of PBDE-209. Two nonabromodiphenyl ethers (PBDE-208, PBDE-207), four octabromodiphenyl ethers (PBDE-203, PBDE-202, PBDE-197, PBDE-196) and one heptabromodiphenyl ethers (PBDE-183) were formed with the decomposition of PBDE-209, demonstrating that the main aerobic transformation mechanism of PBDE-209 was debromination. PMID:23942021

Shi, Guangyu; Yin, Hua; Ye, Jinshao; Peng, Hui; Li, Jun; Luo, Chunling

2013-11-01

350

POLYBROMINATED DIPHENYL ETHERS (PBDES) IN AMERICAN MOTHERS' MILK  

EPA Science Inventory

No previous reports exist on polybrominated diphenyl ether (PBDE) congeners in individual American mothers' milk. This report on PBDEs is an extension of our previous studies on concentrations of dioxins, dibenzofurans, PCBs, and other chlorinated organics in human milk in a num...

351

Dibenzo crown ether layer formation on muscovite mica.  

PubMed

Stable layers of crown ethers were grown on muscovite mica using the potassium-crown ether interaction. The multilayers were grown from solution and from the vapor phase and were analyzed with atomic force microscopy (AFM), matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry, and surface X-ray diffraction (SXRD). The results show that the first molecular layer of the three investigated dibenzo crown ethers is more rigid than the second because of the strong interaction of the first molecular layer with the potassium ions on the surface of muscovite mica. SXRD measurements revealed that for all of the investigated dibenzo crown ethers the first molecule lies relatively flat whereas the second lies more upright. The SXRD measurements further revealed that the molecules of the first layer of dibenzo-15-crown-5 are on top of a potassium atom, showing that the binding mechanism of this layer is indeed of the coordination complex form. The AFM and SXRD data are in good agreement, and the combination of these techniques is therefore a powerful way to determine the molecular orientation at surfaces. PMID:25263250

de Poel, Wester; Pintea, Stelian; de Jong, Aryan; Drnec, Jakub; Carlà, Francesco; Felici, Roberto; op den Camp, Huub; Elemans, Johannes A A W; van Enckevort, Willem J P; Rowan, Alan E; Vlieg, Elias

2014-10-28

352

Aqueous alkali metal hydroxide insoluble cellulose ether membrane  

NASA Technical Reports Server (NTRS)

A membrane that is insoluble in an aqueous alkali metal hydroxide medium is described. The membrane is a resin which is a water-soluble C2-C4 hydroxyalkyl cellulose ether polymer and an insolubilizing agent for controlled water sorption, a dialytic and electrodialytic membrane. It is particularly useful as a separator between electrodes or plates in an alkaline storage battery.

Hoyt, H. E.; Pfluger, H. L. (inventors)

1969-01-01

353

Clinical evaluation of pediatric ethylene glycol monobutyl ether poisonings.  

PubMed

Ethylene glycol butyl ether, CAS 111-76-2, an ingredient in many popular commercial window/glass cleaners, is known to produce equal if not greater toxicity than ethylene glycol when administered to animals. Treatment recommendations for human poisonings are based upon animal data and include the use of ethanol therapy to inhibit the production of toxic metabolites. No human experiential data exist to accurately assess human toxicity or to verify treatment modalities. A 5 month retrospective review of all glass cleaner ingestions reported to a regional poison information center disclosed 24 pediatric patients, ages 7 mo to 9 y, who ingested 5-300 mL of a liquid glass cleaning product containing ethylene glycol butyl ether. All ingestions were reported within 5 min of ingestion, and all 24 children were asymptomatic at that time and subsequently. The product concentrations of ethylene glycol butyl ether ranged from 0.5% to 9.9%. Two of the 24 children ingested > 15 mL and were treated by gastric emptying and 24 h hospital observation. Neither hospitalized child suffered symptoms consistent with hemolysis, nervous system depression, acidosis, or renal compromise. Dilution with oral fluids at home is considered appropriate treatment of pediatric ingestions of < 10 mL of a commercial liquid glass/window cleaners containing < 10% ethylene glycol butyl ether. PMID:1359160

Dean, B S; Krenzelok, E P

1992-01-01

354

Toluene 2-Monooxygenase-Dependent Growth of Burkholderia cepacia G4/PR1 on Diethyl Ether  

PubMed Central

Aerobic bacterial growth on aromatic hydrocarbons typically requires oxygenase enzymes, which are known to fortuitously oxidize nongrowth substrates. In this study, we found that oxidation of diethyl ether by toluene 2-monooxygenase supported more rapid growth of Burkholderia cepacia G4/PR1 than did the aromatic substrates n-propylbenzene and o-xylene. The wild-type Burkholderia cepacia G4 failed to grow on diethyl ether. Purified toluene 2-monooxygenase protein components oxidized diethyl ether stoichiometrically to ethanol and acetaldehyde. Butyl methyl ether, diethyl sulfide, and 2-chloroethyl ethyl ether were oxidized by B. cepacia G4/PR1. PMID:16535583

Hur, H.; Newman, L. M.; Wackett, L. P.; Sadowsky, M. J.

1997-01-01

355

(Liquid + liquid) phase equilibria of 1-alkyl-3-methylimidazolium methylsulfate with alcohols, or ethers, or ketones  

Microsoft Academic Search

Solubilities of binary mixtures that contain a room-temperature ionic liquid and an organic solvent – namely, 1,3-dimethylimidazolium methylsulfate, [mmim][CH3SO4], or 1-butyl-3-methylimidazolium methylsulfate, [bmim][CH3SO4] with an alcohol (hexan-1-ol, or octan-1-ol, or nonan-1-ol, or decan-1-ol), or an ether (dipropyl ether, or dibutyl ether, or methyl-1,1-dimethylethyl ether, or methyl-1,1-dimethylpropyl ether), or a ketone (pentan-2-one, or pentan-3-one, or hexan-2-one, or heptan-4-one, or cyclopentanone) –

Urszula Doma?ska; Aneta Pobudkowska; Frank Eckert

2006-01-01

356

RATE CONSTANTS FOR THE REACTIONS OF OH RADICALS AND CL ATOMS WITH DI-N-PROPYL ETHER AND DI-N-BUTYL ETHER AND THEIR DEUTERATED ANALOGS. (R825252)  

EPA Science Inventory

Using relative rate methods, rate constants for the gas-phase reactions of OH radicals and Cl atoms with di- n -propyl ether, di- n -propyl ether-d14, di- n -butyl ether and di- n -butyl ether-d18 have been measured at 296 ? 2 K and atmos...

357

Changes in Dimethyl Sulfide Oceanic Distribution due to Climate Change  

SciTech Connect

Dimethyl sulfide (DMS) is one of the major precursors for aerosols and cloud condensation nuclei in the marine boundary layer over much of the remote ocean. Here they report on coupled climate simulations with a state-of-the-art global ocean biogeochemical model for DMS distribution and fluxes using present-day and future atmospheric CO{sub 2} concentrations. They find changes in zonal averaged DMS flux to the atmosphere of over 150% in the Southern Ocean. This is due to concurrent sea ice changes and ocean ecosystem composition shifts caused by changes in temperature, mixing, nutrient, and light regimes. The largest changes occur in a region already sensitive to climate change, so any resultant local CLAW/Gaia feedback of DMS on clouds, and thus radiative forcing, will be particularly important. A comparison of these results to prior studies shows that increasing model complexity is associted with reduced DMS emissions at the equator and increased emissions at high latitudes.

Cameron-Smith, P; Elliott, S; Maltrud, M; Erickson, D; Wingenter, O

2011-02-16

358

Eosinophilic cystitis after bladder instillation with dimethyl sulfoxide.  

PubMed

Eosinophilic cystitis is a rare and poorly understood disorder. We report the first case of an acute flare of eosinophilic cystitis in a 51-year-old woman after bladder instillation with dimethyl sulfoxide (DMSO) for presumed interstitial cystitis. The patient presented with severe bladder pain, fever, and eosinophilia several hours after instillation. These symptoms were unresponsive to conventional analgesic and antibiotic treatments. Cystoscopy revealed erythema and exudate at the bladder walls, along with edema of both ureteral orifices. Bladder biopsies demonstrated massive eosinophilic infiltration of the bladder, confirming the diagnosis of eosinophilic cystitis. Urologists should bear in mind this clinical entity, particularly when DMSO is administered to patients with multiple drug allergies. PMID:15183980

Abramov, Yoram; Goldberg, Roger P; McGuire, Michael; Golden, Barbara; Gandhi, Sanjay; Sand, Peter K

2004-06-01

359

Changes in dimethyl sulfide oceanic distribution due to climate change  

SciTech Connect

Dimethyl sulfide (DMS) is one of the major precursors for aerosols and cloud condensation nuclei in the marine boundary layer over much of the remote ocean. Here we report on coupled climate simulations with a state-of-the-art global ocean biogeochemical model for DMS distribution and fluxes using present-day and future atmospheric CO{sub 2} concentrations. We find changes in zonal averaged DMS flux to the atmosphere of over 150% in the Southern Ocean. This is due to concurrent sea ice changes and ocean ecosystem composition shifts caused by changes in temperature, mixing, nutrient, and light regimes. The largest changes occur in a region already sensitive to climate change, so any resultant local CLAW/Gaia feedback of DMS on clouds, and thus radiative forcing, will be particularly important. A comparison of these results to prior studies shows that increasing model complexity is associated with reduced DMS emissions at the equator and increased emissions at high latitudes.

Elliott, Scott [Los Alamos National Laboratory (LANL); Erickson III, David J [ORNL

2011-01-01

360

Poly[hexa-?-acetato-bis­(dimethyl sulfoxide)­trimanganese(II)  

PubMed Central

In the title complex, [Mn3(CH3CO2)6(C2H6SO)2]n, the MnII ions exhibit similar MnO6 octa­hedral coordination geometries but with different coordination environments. One type of MnII ion is surrounded by five acetate groups and a terminal dimethyl sulfoxide group, while the other lies on a twofold axis and is coordinated by six O atoms from three symmetry-related acetate ions. The acetate anions exhibit three independent bridging modes, which flexibly bridge the MnII ions along the c-axis direction, forming an infinite chain structure; the chains are further inter­connected through weak C—H?O and C—H?S hydrogen-bonding inter­actions. PMID:21588893

Wan, Chong-Qing; Xiao, Nai-You; Wang, Zi-Jia

2010-01-01

361

Effect of decabromodiphenyl ether (BDE 209) and dibromodiphenyl ether (BDE 15) on soil microbial activity and bacterial community composition  

Microsoft Academic Search

There is now increasing concern regarding the effect of polybrominated diphenyl ethers (PBDEs) on the environment. These compounds are widely used as fire retardants and by the electronic industry. Our study examined the effects of adding different doses of BDE 15 and BDE 209 on the soil microbial activities and function by using denaturing gradient gel electrophoresis (DGGE), fluorescence in

Lu Liu; Wei Zhu; Lin Xiao; Liuyan Yang

2011-01-01

362

Use of fluorinated polybrominated diphenyl ethers and simplified cleanup for the analysis of polybrominated diphenyl ethers in house dust  

EPA Science Inventory

A simple, cost-effective method is described for the analysis of polybrominated diphenyl ethers (PBDEs) in house dust using pressurized fluid extraction, cleanup with modified silica solid phase extraction tubes, and fluorinated internal standards. There are 14 PBDE congeners inc...

363

Aryl ether as a Negishi coupling partner: an approach for constructing C-C bonds under mild conditions.  

PubMed

An etheric Negishi coupling: The first cross-coupling reaction between aryl alkyl ethers and dianion-type zincate reagents to afford biaryl compounds through selective cleavage of the etheric C(sp(2))-O bond was developed. Dianion-type zincates showed excellent reactivity toward the aromatic ethers under mild conditions, with good functional group compatibility (see scheme). PMID:22374683

Wang, Chao; Ozaki, Takashi; Takita, Ryo; Uchiyama, Masanobu

2012-03-19

364

Amorphous phase separation in crystallizable polymer blends based on poly (aryl ether ketones) and poly (ether imide)  

SciTech Connect

The morphology of a series of miscible crystallizable blends based on poly (aryl ether ketones) [PAEK] and poly (ether imide) [PEI] has been investigated as a function of blend composition and crystallization condition by dielectric relaxation spectroscopy. For blends of poly (ether ether ketone) [PEEK] and PEI, dielectric scans of the crystallized samples reveal two glass-rubber relaxations corresponding to the coexistence of a mixed interlamellar amorphous phase, and a pure PEI phase located in interfibrillar/interspherulitic regions. The exclusion of a significant fraction of PEI outside of the crystal lamellae reflects a fundamental change in the nature of interaction between the interlamellar PEEK segments and the PEI chains owing to the constraints imposed on the PEEK segments by the crystal surfaces. The degree of PEI exclusion is dependent upon kinetic factors, i.e. the rate of PEEK crystallization relative to the rate of PEI diffusion away from the advancing crystal front. As a result, lower crystallization temperatures lead to an increase in the amount of PEI trapped in the interlamellar regions. In this work, the morphological characteristics of the PEEK/PEI blends are compared with those of blends comprised of poly (ether ketone ketone) [PEKK] and PEI. The introduction of the {open_quotes}kinked{close_quote} isophthalate moiety in the PEKK backbone has been shown to disrupt the persistence of order at the crystal-amorphous interface, and thereby leads to a reduction in the degree of constraint imposed by the crystal lamellae on the amorphous (interlamellar) PEKK segments. The impact of this reduction in crystalline constraint on the nature of the PEKK/PEI intersegmental interactions and the corresponding PEI segregation is discussed.

Kalika, D.S.; Bristow, J.F. [Univ. of Kentucky, Lexington, KY (United States)

1996-12-31

365

Air-soil exchange of dimethyl sulfide, carbon disulfide, and dimethyl disulfide in three subtropical forests in south China  

NASA Astrophysics Data System (ADS)

The exchange of dimethyl sulfide (DMS), carbon disulfide (CS2), and dimethyl disulfide (DMDS) between soil and the atmosphere was investigated in three subtropical forests in south China, namely, a monsoon evergreen broadleaf forest (BF) in climax successional stage, a pine and broadleaf mixed forest (MF) in midsuccessional stage, and a pine forest (PF) in primary successional stage. The forest soils acted as sources for DMS with average flux in BF (1.27 ± 1.40 pmol m-2 s-1) significantly higher than those in MF (0.46 ± 0.30 pmol m-2 s-1) or in PF (0.47 ± 0.36 pmol m-2 s-1). Litter-removed plots showed 55%, 21%, and 53% lower DMS emission fluxes compared to litter-remained plots in BF, MF, and PF, respectively, suggesting the litter layer made evident contribution to DMS emission. DMS fluxes were significantly higher in rain seasons than in dry seasons. Dependence of DMS fluxes on soil temperature varied in the three forests, and significant correlations between DMS fluxes and soil temperature were only observed in BF and MF. No significant correlation was found between soil water content and DMS fluxes. However, DMS fluxes were found to be significantly correlated with soil temperature and water content together in polynomial forms with an order of 2. DMS fluxes were also exponentially correlated with CO2 fluxes. CS2 and DMDS fluxes showed no consistent direction. CS2 fluxes varied between -8.51 and 4.72 pmol m-2 s-1 and DMDS fluxes between -0.25 and 2.00 pmol m-2 s-1, respectively. No clear patterns were found for the influence of litter layer on the CS2 or DMDS fluxes.

Yi, Zhigang; Wang, Xinming; Ouyang, Mingan; Zhang, Deqiang; Zhou, Guoyi

2010-09-01

366

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

PubMed Central

Several propane-oxidizing bacteria were tested for their ability to degrade gasoline oxygenates, including methyl tert-butyl ether (MTBE), ethyl tert-butyl ether (ETBE), and tert-amyl methyl ether (TAME). Both a laboratory strain and natural isolates were able to degrade each compound after growth on propane. When propane-grown strain ENV425 was incubated with 20 mg of uniformly labeled [14C]MTBE per liter, the strain converted > 60% of the added MTBE to 14CO2 in < 30 h. The initial oxidation of MTBE and ETBE resulted in the production of nearly stoichiometric amounts of tert-butyl alcohol (TBA), while the initial oxidation of TAME resulted in the production of tert-amyl alcohol. The methoxy methyl group of MTBE was oxidized to formaldehyde and ultimately to CO2. TBA was further oxidized to 2-methyl-2-hydroxy-1-propanol and then 2-hydroxy isobutyric acid; however, neither of these degradation products was an effective growth substrate for the propane oxidizers. Analysis of cell extracts of ENV425 and experiments with enzyme inhibitors implicated a soluble P-450 enzyme in the oxidation of both MTBE and TBA. MTBE was oxidized to TBA by camphor-grown Pseudomonas putida CAM, which produces the well-characterized P-450cam, but not by Rhodococcus rhodochrous 116, which produces two P-450 enzymes. Rates of MTBE degradation by propane-oxidizing strains ranged from 3.9 to 9.2 nmol/min/mg of cell protein at 28 degrees C, whereas TBA was oxidized at a rate of only 1.8 to 2.4 nmol/min/mg of cell protein at the same temperature. PMID:9361407

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

1997-01-01

367

Effects of 4,4-dimethyl-5,8-dihydroxynaphtalene-1-one and 4,4-dimethyl-5,8-dihydroxytetralone derivatives on tumor cell respiration.  

PubMed

A set of structurally related compounds incorporating a carbonyl group in the ortho position with regard to a phenol function were tested against the TA3 mouse carcinoma cell line and its multidrug-resistant variant TA3-MTX-R. The series consists of 2'-hydroxyacetophenone, 4'-hydroxyacetophenone 2',5'-dihydroxyacetophenone, 4-acetyl-3,3-dimethyl-5-hydroxy-2-morpholino-2,3-dihydrobenzobfuran, five 4,4-dimethyl-5,8-dioxygenated naphtalene-1-ones and three 4,4-dimethyl-5,8-dioxygenated tetralones. A tentative structure-activity relationship was found for this family of substances, suggesting that a coplanar ortho-carbonyl-1,4-hydroquinone motif is able to cause inhibition of cellular respiration. PMID:12110329

Araya-Maturana, Ramiro; Delgado-Castro, Tomás; Gárate, Mario; Ferreira, Jorge; Pavani, Mario; Pessoa-Mahana, Hernán; Cassels, Bruce K

2002-09-01

368

77 FR 47291 - Residues of Didecyl Dimethyl Ammonium Chloride; Exemption From the Requirement of a Tolerance  

Federal Register 2010, 2011, 2012, 2013, 2014

...in evaporative humidifiers. Evaporative humidifiers, unlike other types of humidifiers, do not generate and expel treated droplets or mist. The Didecyl dimethyl ammonium chloride will volatilize in, at most, negligible amounts from treated water in...

2012-08-08

369

Does dimethyl sulfoxide increase protein immunomarking efficiency for dispersal and predation studies?  

Technology Transfer Automated Retrieval System (TEKTRAN)

Marking biological control agents facilitates studies of dispersal and predation. This study examines the effect of a biological solvent, dimethyl sulfoxide (DMSO), on retention of immunoglobulin G (IgG) protein solutions applied to Diorhabda carinulata (Desbrochers) (Coleoptera: Chrysomelidae) eit...

370

Effect of dimethyl sulphoxide on the crystal structure of porcine pepsin  

SciTech Connect

The structure of porcine pepsin crystallized in the presence of dimethyl sulphoxide has been analysed by X-ray crystallography to obtain insights into the structural events that occur at the onset of chemical denaturation of proteins. The results show that one dimethyl sulphoxide molecule occupies a site on the surface of pepsin interacting with two of its residues. An increase in the average temperature factor of pepsin in the presence of dimethyl sulphoxide has been observed indicating protein destabilization induced by the denaturant. Significant increase in the temperature factor and weakening of the electron density have been observed for the catalytic water molecule located between the active aspartates. The conformation of pepsin remains unchanged in the crystal structure. However, the enzyme assay and circular dichroism studies indicate that dimethyl sulphoxide causes a slight change in the secondary structure and complete loss of activity of pepsin in solution.

Kesavulu, Muppuru Muni [Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560 012, Karnataka (India); Ramasubramanian, Sundaramoorthy [Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560 012, Karnataka (India); Suguna, Kaza [Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560 012, Karnataka (India)]. E-mail: suguna@mbu.iisc.ernet.in

2005-06-17

371

77 FR 14324 - National Volatile Organic Compound Emission Standards for Aerosol Coatings-Addition of Dimethyl...  

Federal Register 2010, 2011, 2012, 2013, 2014

...is a rule that establishes national reactivity-based emission standards for the aerosol coatings category (aerosol spray paints) under the Clean Air Act. This proposed action adds three compounds: dimethyl carbonate, benzotrifluoride, and...

2012-03-09

372

40 CFR 180.372 - 2,6-Dimethyl-4-tridecylmorpholine; tolerances for residues.  

Code of Federal Regulations, 2012 CFR

...fungicide 2,6-dimethyl-4-tridecylmorpholine in or on the following food commodity: Commodity Parts per million Banana 1 1.0 1 There are no U.S. registrations. (b) Section 18 emergency exemptions . [Reserved] (c)...

2012-07-01

373

40 CFR 180.372 - 2,6-Dimethyl-4-tridecylmorpholine; tolerances for residues.  

Code of Federal Regulations, 2013 CFR

...fungicide 2,6-dimethyl-4-tridecylmorpholine in or on the following food commodity: Commodity Parts per million Banana 1 1.0 1 There are no U.S. registrations. (b) Section 18 emergency exemptions . [Reserved] (c)...

2013-07-01

374

40 CFR 180.372 - 2,6-Dimethyl-4-tridecylmorpholine; tolerances for residues.  

Code of Federal Regulations, 2010 CFR

...fungicide 2,6-dimethyl-4-tridecylmorpholine in or on the following food commodity: Commodity Parts per million Banana 1 1.0 1 There are no U.S. registrations. (b) Section 18 emergency exemptions . [Reserved] (c)...

2010-07-01

375

40 CFR 180.372 - 2,6-Dimethyl-4-tridecylmorpholine; tolerances for residues.  

Code of Federal Regulations, 2014 CFR

...fungicide 2,6-dimethyl-4-tridecylmorpholine in or on the following food commodity: Commodity Parts per million Banana 1 1.0 1 There are no U.S. registrations. (b) Section 18 emergency exemptions. [Reserved] (c)...

2014-07-01

376

40 CFR 180.372 - 2,6-Dimethyl-4-tridecylmorpholine; tolerances for residues.  

Code of Federal Regulations, 2011 CFR

...fungicide 2,6-dimethyl-4-tridecylmorpholine in or on the following food commodity: Commodity Parts per million Banana 1 1.0 1 There are no U.S. registrations. (b) Section 18 emergency exemptions . [Reserved] (c)...

2011-07-01

377

21 CFR 524.981e - Fluocinolone acetonide, dimethyl sulfoxide otic solution.  

Code of Federal Regulations, 2013 CFR

...ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS OPHTHALMIC AND TOPICAL DOSAGE FORM NEW ANIMAL DRUGS § 524.981e Fluocinolone acetonide, dimethyl sulfoxide otic solution. (a)...

2013-04-01

378

21 CFR 524.981e - Fluocinolone acetonide, dimethyl sulfoxide otic solution.  

Code of Federal Regulations, 2012 CFR

...ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS OPHTHALMIC AND TOPICAL DOSAGE FORM NEW ANIMAL DRUGS § 524.981e Fluocinolone acetonide, dimethyl sulfoxide otic solution. (a)...

2012-04-01

379

21 CFR 524.981e - Fluocinolone acetonide, dimethyl sulfoxide otic solution.  

Code of Federal Regulations, 2011 CFR

...ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS OPHTHALMIC AND TOPICAL DOSAGE FORM NEW ANIMAL DRUGS § 524.981e Fluocinolone acetonide, dimethyl sulfoxide otic solution. (a)...

2011-04-01

380

21 CFR 524.981e - Fluocinolone and dimethyl sulfoxide otic solution.  

Code of Federal Regulations, 2014 CFR

...ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS OPHTHALMIC AND TOPICAL DOSAGE FORM NEW ANIMAL DRUGS § 524.981e Fluocinolone and dimethyl sulfoxide otic solution. (a)...

2014-04-01

381

CATALYSTS FOR HIGH CETANE ETHERS AS DIESEL FUELS  

SciTech Connect

A novel 1,2-ethanediol, bis(hydrogen sulfate), disodium salt precursor-based solid acid catalyst with a zirconia substrate was synthesized and demonstrated to have significantly enhanced activity and high selectivity in producing methyl isobutyl ether (MIBE) or isobutene from methanol-isobutanol mixtures. The precursor salt was synthesized and provided by Dr. T. H. Kalantar of the M.E. Pruitt Research Center, Dow Chemical Co., Midland, MI 48674. Molecular modeling of the catalyst synthesis steps and of the alcohol coupling reaction is being carried out. A representation of the methyl transfer from the surface activated methanol molecule (left) to the activated oxygen of the isobutanol molecule (right) to form an ether linkage to yield MIBE is shown.

Kamil Klier; Richard G. Herman; James G.C. Shen; Qisheng Ma

2000-08-31

382

Introducing the Oxypro process: A new refinery ethers process  

SciTech Connect

The new Oxypro process developed by UOP is a unique, low-cost, refinery-based catalytic process for the production of diisopropyl ether (DIPE) from propylene and water. The ether DIPE has high octane, low vapor pressure, and excellent gasoline blending properties. The Oxypro process is especially well suited for processing propylene derived from the fluid catalytic cracking unit (FCCU) within the refinery. After amine and Merox treating, the FCCU-derived propylene is fed directly along with water to the Oxypro process. The propylene and water are converted to DIPE at more than 98 wt-% selectivity. The Oxypro product has more than 98 wt-% DIPE purity and octanes of 112 research octane number clear (RONC) and 98 motor octane number clear (MONC).

Davis, S.P.; Marker, T.L.; Schmidt, R.J.; Keesom, W.H. [UOP, Des Plaines, IL (United States)

1995-09-01

383

Radical arylation of phenols, phenyl ethers, and furans.  

PubMed

Radical arylations of para-substituted phenols and phenyl ethers proceeded with good regioselectivity at the ortho position with respect to the hydroxy or alkoxy group. The reactions were conducted with arenediazonium salts as the aryl radical source, titanium(III) chloride as the reductant, and diluted hydrochloric acid as the solvent. Substituted biaryls were obtained from hydroxy- and alkoxy-substituted benzylamines, phenethylamines, and aromatic amino acids. The methodology described offers a fast, efficient, and cost-effective new access to diversely functionalized biphenyl alcohols and ethers. Free phenolic hydroxy groups, aromatic and aliphatic amines, as well as amino acid substructures, are well tolerated. Two examples for the applicability of the methodology are the partial synthesis of a beta-secretase inhibitor and the synthesis of a calcium-channel modulator. PMID:20066707

Wetzel, Alexander; Pratsch, Gerald; Kolb, Roman; Heinrich, Markus R

2010-02-22

384

Hydrothermal conversion of lignin to substituted phenols and aromatic ethers.  

PubMed

Hydrothermal liquefaction of lignin was performed using methanol and ethanol at various temperatures (200, 250 and 280°C) and residence times of 15, 30 and 45min. Maximum liquid product yield (85%) was observed at 200°C and 15min residence time using methanol. Increase in temperature was seen to decrease the liquid products yield. With increase in residence time, liquid yields first increased and then decreased. FTIR and (1)H NMR showed the presence of substituted phenols and aromatic ethers in liquid products and breakage of ?-O-4 or/and ?-O-4 ether bonds present in lignin during hydrothermal liquefaction was confirmed through FTIR of bio-residue. In comparison to the existing literature information, higher lignin conversion to liquid products and maximum carbon conversion (72%) was achieved in this study. PMID:24636917

Singh, Rawel; Prakash, Aditya; Dhiman, Shashi Kumar; Balagurumurthy, Bhavya; Arora, Ajay K; Puri, S K; Bhaskar, Thallada

2014-08-01

385

Photoinitiated polymerization of vinyl ether-based systems  

Microsoft Academic Search

The photoinitiated polymerization of vinyl ether (VE)-based coatings has been studied by real-time infrared (RTIR) spectroscopy. In the presence of diaryliodonium or triarylsulfonium photoinitiators, the cationic polymerization occurs rapidly upon UV-exposure and continues to proceed upon storage in the dark. Increasing the formulation viscosity by introduction of telechelic VE oligomers was found to have a strong slowing down effect on

C Decker; C Bianchi; D Decker; F Morel

2001-01-01

386

Theoretical study on the chemical properties of polybrominated diphenyl ethers  

Microsoft Academic Search

Density functional theory calculations at the B3LYP\\/6-31+G(d) and B3LYP\\/aug-cc-pVDZ levels were performed to obtain the equilibrium structures, thermodynamic properties, and electron affinities (EA) of 14 polybrominated diphenyl ether (PBDE) congeners in the gas phase. All congeners except for those of symmetric BDE are found to have two or more conformational isomers. The optimized geometries of the most stable conformational isomers

Ya-Ying Zhao; Fu-Ming Tao; Eddy Y. Zeng

2008-01-01

387

Polybrominated Diphenyl Ethers in the Sediments of the Great Lakes.  

E-print Network

Polybrominated Diphenyl Ethers in the Sediments of the Great Lakes. 2. Lakes Michigan and Huron W E, University of Illinois at Chicago, Chicago, Illinois 60612 Sediment cores were taken in 2002 in Lakes) in the surficial sediments range from 1.7 to 4 ng g-1 for Lake Michigan and from 1.0 to 1.9 ng g-1 for Lake Huron

Rockne, Karl J.

388

Ether agogo Potassium Channels as Human Cervical Cancer Markers  

Microsoft Academic Search

Ether ago-go (EAG) potassium channels display oncogenic properties. In normal tissues, EAG mRNA is almost exclusively expressed in brain, but it is expressed in several somatic cancer cell lines, including HeLa, from cervix. Antisense experiments against eag reduce cell proliferation in some cancer cell lines, and inhibition of EAG-mediated currents has been suggested to decrease cell proliferation in a melanoma

Luz Maria Barajas Farias; Deysi Bermudez Ocana; Lorenza Diaz; Fernando Larrea; Euclides Avila-Chavez; Adriana Cadena; Luz Maria Hinojosa; Gerardo Lara; Luis Alberto Villanueva; Carlos Vargas; Elizabeth Hernandez-Gallegos; Ignacio Camacho-Arroyo; Alfonso Duenas-Gonzalez; Enrique Perez-Cardenas; Luis A. Pardo; Angelica Morales; Lucia Taja-Chayeb; Juan Escamilla; Carmen Sanchez-Pena; Javier Camacho

2004-01-01

389

Thiophenyl ether disiloxanes and trisiloxanes useful as lubricant fluids  

NASA Technical Reports Server (NTRS)

The characteristics of organosilicon compounds for lubrication under extreme conditions are discussed. The substances considered are thiophenyl ether disiloxanes and trisiloxanes. These substances have low pour points and a high degree of radiation resistance. Substitution of sulfur for the phenoxy group oxygen of either siloxane compounds has been found to result in a marked improvement in lubricity. The chemical formulas of the organic compounds are presented.

Bilow, N.; Akawie, R. I. (inventors)

1974-01-01

390

Secondary Li battery incorporating 12-Crown-4 ether  

NASA Technical Reports Server (NTRS)

A rechargeable lithium battery which utilizes a polyethylene oxide (PEO) solid polymeric electrolyte complexed with a lithium salt is disclosed. The conductivity is increased an order of magnitude and interfacial charge transfer resistance is substantially decreased by incorporating a minor amount of 12-Crown-4 ether in the PEO-lithium salt solid electrolyte film. Batteries containing the improved electrolyte permit operation at a lower temperature with improved efficiency.

Nagasubramanian, Ganesan (inventor); Distefano, Salvador (inventor)

1992-01-01

391

Indium-catalyzed intramolecular hydroarylation of aryl propargyl ethers.  

PubMed

Indium(iii) halides catalyze efficiently the intramolecular hydroarylation (IMHA) of aryl propargyl ethers. The reaction proceeds regioselectively with terminal and internal alkynes bearing electron-rich and electron-deficient substituents in the benzenes and alkynes affording only the 6-endo dig cyclization product. Additionally, a sequential indium-catalyzed IMHA and palladium-catalyzed Sonogashira coupling can be performed in one reaction vessel. Experiments with deuterium support a mechanism through electrophilic aromatic substitution. PMID:25376147

Alonso-Marañón, Lorena; Martínez, M Montserrat; Sarandeses, Luis A; Sestelo, José Pérez

2015-01-14

392

THERMODYNAMIC EVALUATION OF PREDICTED FLUORINATED ETHER, ETHANE, AND PROPANE AZEOTROPES  

EPA Science Inventory

The paper gives results of thermodynamic analyses, using basic thermophysical property data, to evaluate seven predicted fluorinated ether, ethane, and propane azeotropes: E125/RC270, E125/R134a, E143a/R134, R134a/E143a, E143a/ R152a, R134/R245cb, and R245cb/R227ea. he performanc...

393

Patch test with ether extracts in salicaceae allergy.  

PubMed

A total of 23 cases suggestive of airborne contact dermatitis were patch tested with ether extracts of flowers and leaves of populus sp. and salix sp. in a study conducted in Ladakh at an altitude of 3445 meters above sea level. Overall positivity was found in 12 (52.17%), with populus sp. alone in 7 (30.43%), salix sp. alone in 4 (17.39%) and to both in one (8.33%). PMID:17656882

Sawhney, M P S

2002-01-01

394

Dimethylation of Histone H3 at Lysine 36 Demarcates Regulatory and Nonregulatory Chromatin Genome-Wide  

Microsoft Academic Search

Set2p, which mediates histone H3 lysine 36 dimethylation (H3K36me2) in Saccharomyces cerevisiae, has been shown to associate with RNA polymerase II (RNAP II) at individual loci. Here, chromatin immunoprecipita- tion-microarray experiments normalized to general nucleosome occupancy reveal that nucleosomes within open reading frames (ORFs) and downstream noncoding chromatin were highly dimethylated at H3K36 and that Set2p activity begins at a

Bhargavi Rao; Yoichiro Shibata; Brian D. Strahl; Jason D. Lieb

2005-01-01

395

Detection of dimethyl sulfone in the human brain by in vivo proton magnetic resonance spectroscopy  

Microsoft Academic Search

We wish to report the detection of dimethyl sulfone (methylsulfonylmethane, C2H6O2S) in the brain of a normal 62-year-old male using in vivo proton magnetic resonance spectroscopy. The presence of this exogenous metabolite resulted from ingestion of a dietary supplement containing dimethyl sulfone. The concentration of this compound in the brain was measured to be 2.4 mmol, with a washout “half

Stephen E Rosea; Jonathan B Chalk; Graham J Galloway; David M Doddrell

2000-01-01

396

Cardiovascular pharmacological characterization of novel 2,3-dimethyl-2-butylamine derivatives in rats  

Microsoft Academic Search

The electrophysiological properties and pharmacological effects of newly synthesized 2,3-dimethyl-2-butylamine derivatives on the rat cardiovascular system were evaluated both in vitro and in vivo.In conventional whole-cell recordings, 2,3-dimethyl-2-butylamine derivatives with ethyl, isopropyl, allyl, butyl, 1-methyl-propyl or cyclopropylmethyl substituents on the amine side chain had potent effects on the outward potassium currents in isolated rat tail arterial smooth muscle cell membranes.

Yu-Ping Chen; Cai-Rong Qiu; Hai Wang

2004-01-01

397

Influence of dimethyl formamide pulping of wheat straw on cellulose degradation and comparison with Kraft process  

Microsoft Academic Search

The pulping of wheat straw with dimethyl formamide was studied in order to investigate the effects of the cooking variables (temperature (190°C, 200°C, and 210°C) and time (120min, 150min, and 180min) and organic solvent ratio (30%, 50%, and 70%) dimethyl formamide (DMF+water) value) on the degradation of cellulose and degree of polymerization (DP) of organosolv pulp. The SCAN viscosity was

Y. Ziaie-Shirkolaee; J. Mohammadi-Rovshandeh; P. Rezayati-Charani; M. B. Khajeheian

2008-01-01

398

Mid-infrared absorption spectra of dimethyl methylphosphonate as molecular simulant of nerve agents  

NASA Astrophysics Data System (ADS)

The fine mid-infrared absorption features of dimethyl methylphosphonate vapor have been characterized by using Fourier transforms infrared spectroscopy, and the nitrous oxide was used for calibration purpose. The results show that the main P-O-C and P=O bonds related absorption bands of dimethyl methylphosphonate vapor are peaked at 1050.01 and 1275.76 cm^(-1) respectively, those two bands show continuous characteristics at resolution of 0.125 cm^(-1).

Zhang, Yonggang; Cheng, Zhenxing; Li, Aizhen; Feng, Songlin

2006-10-01

399

Experimental studies of the dissociative recombination processes for the dimethyl ether ions CD3OCD2+ and (CD3)2OD+  

NASA Astrophysics Data System (ADS)

Aims: Determination of branching fractions, cross sections and thermal rate coefficients for the dissociative recombination of CD3OCD2+ (0-0.3 eV) and (CD3)2OD+ (0-0.2 eV) at the low relative kinetic energies encountered in the interstellar medium. Methods: The measurements were carried out using merged electron and ion beams at the CRYRING storage ring, Stockholm, Sweden. Results: For (CD3)2OD+ we have experimentally determined the branching fraction for ejection of a single hydrogen atom in the DR process to be maximally 7% whereas 49% of the reactions involve the break up of the COC chain into two heavy fragments and 44% ruptures both C-O bonds. The DR of CD3OCD2+ is dominated by fragmentation of the COC chain into two heavy fragments. The measured thermal rate constants and cross sections are k(T) = 1.7±0.5 × 10-6(T/300)-0.77±0.01 cm3 s-1, ? = 1.2±0.4 × 10-15(Ecm[eV])-1.27±0.01 cm2 and k(T) = 1.7±0.6 × 10-6(T/300)-0.70 ± 0.02 cm3 s-1, ? = 1.7±0.6 × 10-15(Ecm[eV])-1.20±0.02 cm2 for CD3OCD2+ and (CD3)2OD+, respectively.

Hamberg, M.; Österdahl, F.; Thomas, R. D.; Zhaunerchyk, V.; Vigren, E.; Kaminska, M.; Af Ugglas, M.; Källberg, A.; Simonsson, A.; Paál, A.; Larsson, M.; Geppert, W. D.

2010-05-01

400

Determination of polybrominated diphenyl ethers in environmental standard reference materials.  

PubMed

Standard reference materials (SRMs) are valuable tools in developing and validating analytical methods to improve quality assurance standards. The National Institute of Standards and Technology (NIST) has a long history of providing environmental SRMs with certified concentrations of organic and inorganic contaminants. Here we report on new certified and reference concentrations for 27 polybrominated diphenyl ether (PBDE) congeners in seven different SRMs: cod-liver oil, whale blubber, fish tissue (two materials), mussel tissue and sediment (two materials). PBDEs were measured in these SRMs, with the lowest concentrations measured in mussel tissue (SRM 1974b) and the highest in sediment collected from the New York/New Jersey Waterway (SRM 1944). Comparing the relative PBDE congener concentrations within the samples, we found the biota SRMs contained primarily tetrabrominated and pentabrominated diphenyl ethers, whereas the sediment SRMs contained primarily decabromodiphenyl ether (BDE 209). The cod-liver oil (SRM 1588b) and whale blubber (SRM 1945) materials were also found to contain measurable concentrations of two methoxylated PBDEs (MeO-BDEs). Certified and reference concentrations are reported for 12 PBDE congeners measured in the biota SRMs and reference values are available for two MeO-BDEs. Results from a sediment interlaboratory comparison PBDE exercise are available for the two sediment SRMs (1941b and 1944). PMID:17206409

Stapleton, Heather M; Keller, Jennifer M; Schantz, Michele M; Kucklick, John R; Leigh, Stefan D; Wise, Stephen A

2007-04-01

401

Developmental toxicity of diphenyl ether herbicides in birds  

USGS Publications Warehouse

Diphenyl ether herblcldes, includlng nitrofen, have been identified as mammalian teratogens and cause perinatal mortality. American kestrel (Falco sparverius) nestlings were orally dosed for 10 days w1th 5 ul/g of corn oil (controls) or one of the diphenyl ether herbicides (nitrofen, bifenox, or oxyfluorofen). At 500 mg/kg, nitrofen resulted in complete mortality, bifenox in high (66%) mortality, and oxyfluorofen in no mortality. Nitrofen, at 250 mg/kg, reduced nestling growth, as reflected by decreased body weight and bone length. Bifenox at 250 mg/kg had less effect on growth than nitrofen but crown rump, humerus, radiusulna and femur lengths were significantly less than controls. Liver welght (percent of body welght) increased with 50 mg/kg nitrofen. Other manifestations of hepatotoxicity following nitrofen ingestion included increased hepatic GSH peroxidase activity with 0 mg/kg nitrofen, and increased plasma enzyme activities for ALT, AST. and LDHL with 250 mg/kg. Blfenox lngestion (50 mg/kg) resulted in increased hepatlc GSH peroxidase activity. Nitrofen exposure increased total plasma thyroxlne (T4) concentratlon. These findings suggest that altricial nestllng kestrels are more sensitive to diphenyl ether herbicides than precocial young or adult birds.

Hoffman, D.J.; Rattner, B.A.; Bunck, C.M.

1991-01-01

402

Bis-(N-maleimidomethyl) ether: an antisickling reagent.  

PubMed Central

The interaction of bis-(N-maleimidomethyl) ether with oxyhemoglobin results in covalent linkages of both maleimide groups, converting them to succinyl derivatives of beta93 Cys and beta97 His at their sulfhydryl and imidazolyl side chains, respectively. The resultant hemoglobin is stable, and reveals a left-shifted oxyhemoglobin equilibrium curve in which cooperativity is abolished. This reagent readily traverses the red cell membrane and prevents the sickling reaction upon deoxygenation. It appears to affect none of the activities of the red cell enzymes adversely, nor does it appear to affect the red cell membrane. Since there are several defined effects on the stereochemical status of the molecule conferred by interaction with bis-(N-maleimidomethyl) ether, the precise mechanism of the anitsickling effect remains to be elucidated. A more subtle perturberant will be required to specify a precise antisickling effect. By use of bis-(N-maleimidomethyl) ether a precise locus on the beta chain of human hemoglobin S can be perturbed to produce the desired effect. Images PMID:1060096

Zak, S J; Geller, G R; Finkel, B; Tukey, D P; McCormack, M K; Krivit, W

1975-01-01

403

Preparation and antioxidant activity of tyrosyl and homovanillyl ethers.  

PubMed

Preparation of tyrosyl and homovanillyl lipophilic derivatives was carried out as a response to the food industry's increasing demand for new synthetic lipophilic antioxidants. Tyrosyl and homovanillyl ethers were synthesized in high yields by a three-step procedure starting from tyrosol (Ty) and homovanillic alcohol (HMV). The antioxidant activity of these new series of alkyl tyrosyl and homovanillyl ethers was evaluated by the Rancimat test in a lipophilic food matrix and by the FRAP, ABTS and ORAC assays and compared to free Ty and HMV as well as two antioxidants widely used in the food industry, butylhydroxytoluene (BHT) and ?-tocopherol. The results pointed out the higher activity of homovanillyl series in comparison with tyrosyl series with all the assayed methods. However, while both synthetic series were less antioxidant than BHT and ?-tocopherol in a lipophilic matrix after their Rancimat test evaluation, homovanillyl alkyl ethers showed the best reducing power and radical scavenging activity of all evaluated compounds. This batch of synthetic lipophilic compounds, derived from biologically active compounds such as Ty and HMV, provide interesting and potentially bioactive compounds. PMID:25212353

Madrona, A; Pereira-Caro, G; Bravo, L; Mateos, R; Espartero, J L

2011-12-01

404

The interactions of water and perfluorodiethyl ether on Ru(100)  

SciTech Connect

We have studied the interactions of water and perfluorodiethyl ether on Ru(100) in order to model the effects of surface structure and humidity on the bonding and decomposition of perfluoroalkyl ether lubricants with metal surfaces. In order to understand the interactions on Ru(100), we have first investigated the interactions of each of these adsorbates alone on the clean surface. The interactions of water with Ru(100) have been studied using both thermal desorption spectroscopy (TDS) and electron energy loss spectroscopy (EELS). From these studies we conclude that a small amount of water dissociates on this surface (5--10% of a monolayer), but water is adsorbed in a predominantly molecular form on this surface with an increasing degree of hydrogen-bonding with increasing coverage. The effects of hydrogen and oxygen coadsorption on the interactions of water with this surface have also been studied using TDS. Finally, the interactions of coadsorbed water and perfluorodiethyl ether on Ru(100) have been investigated using TDS.

Leavitt, P.

1990-09-21

405

Dehydrogenative ?-oxygenation of ethers with an iron catalyst.  

PubMed

Selective ?-oxidation of ethers under aerobic conditions is a long-pursued transformation; however, a green and efficient catalytic version of this reaction remains challenging. Herein, we report a new family of iron catalysts capable of promoting chemoselective ?-oxidation of a range of ethers with excellent mass balance and high turnover numbers under 1 atm of O2 with no need for any additives. Unlike metalloenzymes and related biomimetics, the catalyst produces H2 as the only byproduct. Mechanistic investigations provide evidence for an unexpected two-step reaction pathway, which involves dehydrogenative incorporation of O2 into the ether to give a peroxobisether intermediate followed by cleavage of the peroxy bond to form two ester molecules, releasing stoichiometric H2 gas in each step. The operational simplicity and environmental friendliness of this methodology affords a useful alternative for performing oxidation, while the unique ability of the catalyst in oxygenating a substrate via dehydrogenation points to a new direction for understanding metalloenzymes and designing new biomimetic catalysts. PMID:24835531

Gonzalez-de-Castro, Angela; Robertson, Craig M; Xiao, Jianliang

2014-06-11

406

Microbial Formation of Dimethyl Sulfide in Anoxic Sphagnum Peat  

PubMed Central

Peat bogs dominated by Sphagnum spp. have relatively high areal rates of dimethyl sulfide (DMS) emission to the atmosphere. DMS was produced in anoxic slurries of Sphagnum peat with a linear time course and with an average rate of 40.4 (range, 22.0 to 68.6) nmol per liter of slurry (middot) day(sup-1) observed in nine batches of slurry. Methanethiol (MeSH) was produced at roughly similar rates over the typical 4- to 8-day incubations. DMS and MeSH production in these acidic (pH 4.2 to 4.6) peats were biological, as they were stopped completely by autoclaving and inhibited strongly by addition of antibiotics and 500 (mu)M chloroform. Endogenous DMS production may be due to the degradation of S-methyl-methionine, dimethyl sulfoxide, or methoxyaromatic compounds (e.g., syringic acid), each of which stimulated DMS formation when added at 5 to 10 (mu)M concentrations. However, on the basis of the high rates of thiol (MeSH and ethanethiol) methylation activity that we observed and the availability of endogenous MeSH, we suggest that methylation of MeSH is the major pathway leading to DMS formation in anaerobic peat. Solid-phase adsorption of MeSH plays a key role in its availability for biomethylation reactions. Additions of acetate (1.5 mM) or compounds which could cause acetate to accumulate (e.g., glucose, alanine, and 2-bromoethanesulfonate) suppressed DMS formation. It is likely that acetogenic bacteria are involved in DMS formation, but our data are insufficient to allow firm conclusions about the metabolic pathways or organisms involved. Our observations are the first which point to the methylation of MeSH as the major mechanism for endogenous DMS production in any environment. The rates of net DMS production observed are sufficient to explain the relatively high fluxes of DMS emitted to the atmosphere from Sphagnum sp.-dominated wetlands. PMID:16535080

Kiene, R. P.; Hines, M. E.

1995-01-01

407

Poly(tetrafluoroethylene) reinforced sulfonated poly(ether ether ketone) membranes for vanadium redox flow battery application  

NASA Astrophysics Data System (ADS)

Poly(tetrafluoroethylene) reinforced sulfonated poly(ether ether ketone) (SPEEK/PTFE) composite membranes are prepared for vanadium redox flow battery (VRB) application. Results show that SPEEK/PTFE composite membranes have lower water uptake and swelling ratio than that of SPEEK membranes due to the PTFE reinforcement. As a result, the composite membranes show higher elongation ratio and better mechanical stability than SPEEK membranes. VRB single cell tests are also carried out to further evaluate their performance. The batteries assembled with SPEEK/PTFE membranes exhibit higher columbic efficiency (CE) and energy efficiency (EE) than that of SPEEK membranes. Furthermore, the composite membranes show much better stability than pristine SPEEK, confirming that PTFE can effectively reinforce membranes to improve their chemical and mechanical stability under VRB operating condition.

Wei, Wenping; Zhang, Huamin; Li, Xianfeng; Mai, Zhensheng; Zhang, Hongzhang

2012-06-01

408

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

PubMed

Ethyl tert butyl ether (ETBE) and tert amyl methyl ether (TAME) are oxygenates used in gasoline in order to reduce emissions from vehicles. The present study investigated their impact on a soil microflora that never was exposed to any contamination before. Therefore, soil was artificially contaminated and incubated over 6 weeks. Substrate induced respiration (SIR) measurements and phospholipid fatty acid (PLFA) analysis indicated shifts in both, microbial function and structure during incubation. The results showed an activation of microbial respiration in the presence of ETBE and TAME, suggesting biodegradation by the microflora. Furthermore, PLFA concentrations decreased in the presence of ETBE and TAME and Gram-positive bacteria became more dominant in the microbial community. PMID:21288640

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

2011-03-15

409

Polymer electrolyte fuel cell performance of poly(arylene ether ketone)-graft-crosslinked-poly(sulfonated arylene ether sulfone)  

NASA Astrophysics Data System (ADS)

The physical properties and polymer electrolyte fuel cell (PEFC) performance of the graft-crosslinked copolymers based on hydrophobic poly(arylene ether ketone) main chains graft-crosslinked with hydrophilic sulfonated poly(arylene ether sulfone) segments were investigated in comparison with those of the sulfonated poly(arylene ether sulfone) multi-block copolymer (bSPAES) and Nafion 112. The graft-crosslinked copolymers with ion exchange capacity (IEC) of 1.90 and 1.58 meq g-1 (GC(1/3) and GC(1/5), respectively) showed the much lower water uptakes and smaller in-plane dimensional changes than bSPAES with IEC of 2.04 meq g-1, resulting in the higher membrane stability. GC(1/3) showed the highest PEFC performances at conditions of 90 °C, 0.2-0.1 MPa and 82-30% RH among these membranes. GC(1/5) also showed the higher or similar PEFC performances when compared to bSPAES and Nafion 112. GC(1/5) showed much better PEFC durability than bSPAES. The graft-crosslinked copolymers have high potential as polymer electrolyte membranes for fuel cell applications.

Hara, Ryousuke; Endo, Nobutaka; Higa, Mitsuru; Okamoto, Ken-ichi; Zhang, Xuan; Bi, Huiping; Chen, Shanshan; Hu, Zhaoxia; Chen, Shouwen

2014-02-01

410

Dimethyl sulfoxide cataract: a model for optical anisotropy fluctuations  

NASA Astrophysics Data System (ADS)

Rat lenses incubated in dimethyl sulfoxide (DMSO)-water binary mixtures of different compositions became turbid. A slight haziness developed up to 0.062 mole fraction f DMSO; at higher concentrations dense turbidity developed. Microscopic examination of the incubated rat lenses showed damage restricted to the epithelium and outer cortex at low DMSO concentrations; maximum damage occurred, in terms of fiber cell swelling, extracellular fluid formation and disintegration of epithelium, at 0.25 mole ratio of DMSO. Scanning electron microscopic observation showed that at high DMSO concentrations, especially at 0.25 mole fraction, the contents of the fiber cells were greatly damaged. Apparently a large part of the crystallins had coalesced around the cytoskeletal bodies. Polarized light-scattering intensity measurements and their analyses indicated that when dense opacities developed at high DMSO concentrations, the major contribution to the turbidity came for the optical anisotropy fluctuations. The change in the organization of the components within the fiber cells disturbs the balance between intrinsic birefringence and form birefringence necessary for transparency. Thus, the DMSO-caused opacification can be described as a good model for the involvement of optical anisotropy fluctuations in cataractogenesis.

Bettelheim, Frederick A.; Churchill, A. C.; Robison, W. G.; Zigler, J. S.

1996-07-01

411

Prediction of dimethyl disulfide levels from biosolids using statistical modeling.  

PubMed

Two statistical models were used to predict the concentration of dimethyl disulfide (DMDS) released from biosolids produced by an advanced wastewater treatment plant (WWTP) located in Washington, DC, USA. The plant concentrates sludge from primary sedimentation basins in gravity thickeners (GT) and sludge from secondary sedimentation basins in dissolved air flotation (DAF) thickeners. The thickened sludge is pumped into blending tanks and then fed into centrifuges for dewatering. The dewatered sludge is then conditioned with lime before trucking out from the plant. DMDS, along with other volatile sulfur and nitrogen-containing chemicals, is known to contribute to biosolids odors. These models identified oxidation/reduction potential (ORP) values of a GT and DAF, the amount of sludge dewatered by centrifuges, and the blend ratio between GT thickened sludge and DAF thickened sludge in blending tanks as control variables. The accuracy of the developed regression models was evaluated by checking the adjusted R2 of the regression as well as the signs of coefficients associated with each variable. In general, both models explained observed DMDS levels in sludge headspace samples. The adjusted R2 value of the regression models 1 and 2 were 0.79 and 0.77, respectively. Coefficients for each regression model also had the correct sign. Using the developed models, plant operators can adjust the controllable variables to proactively decrease this odorant. Therefore, these models are a useful tool in biosolids management at WWTPs. PMID:16287638

Gabriel, Steven A; Vilalai, Sirapong; Arispe, Susanna; Kim, Hyunook; McConnell, Laura L; Torrents, Alba; Peot, Christopher; Ramirez, Mark

2005-01-01

412

Volatile dimethyl polonium produced by aerobic marine microorganisms.  

PubMed

The production of volatile polonium (Po(v)), a naturally occurring radioactive element, by pure cultures of aerobic marine tellurite-resistant microorganisms was investigated. Rhodotorula mucilaginosa, a carotogenic yeast, and a Bacillus sp. strain, a Gram-positive bacterium, generated approximately one and 2 orders of magnitude, respectively, greater amounts of Po(v) compared to the other organisms tested. Gas chromatography-inductively coupled plasma-mass spectrometry (GC-ICP-MS) analysis identified dimethyl polonide (DMPo) as the predominant volatile Po compound in culture headspace of the yeast. This species assignment is based on the exact relation between GC retention times and boiling points of this and other Group VI B analogues (S, Se, and Te). The extent of the biotic Po(v) production correlates exponentially with elevated particulate Po (Po(p)): dissolved Po (Po(aq)) ratios in the cultures, consistent with efficient Po bioaccumulation. Further experimentation demonstrated that some abiotic Po(v) generation is possible. However, high-level Po(v) generation in these cultures is predominantly biotic. PMID:22924583

Bahrou, Andrew S; Ollivier, Patrick R L; Hanson, Thomas E; Tessier, Emmanuel; Amouroux, David; Church, Thomas M

2012-10-16

413

Crosslinking density and resorption of dimethyl suberimidate-treated collagen.  

PubMed

Collagen was purified from bovine Achilles tendon and crosslinked with dimethyl suberimidate (DMS) and glutaraldehyde (GTA). Under optimal conditions, the shrinkage temperature (Ts) was raised to 74 degrees C for collagen crosslinked with DMS and to 80 degrees C for those crosslinked with GTA. Crosslinking density measurements were done on the hydrothermally denatured collagen by the method based on the Flory-Rehner equation. GTA treatment was found to introduce more number of crosslinks than DMS. The maximum tension attained during heating (after shrinkage has occurred) was greater for GTA-treated collagen than for DMS and control. The control collagen membranes broke during heating (at 73 degrees C), while for the crosslinked membranes the tension kept on increasing up to 100 degrees C. The crosslinking density correlated well with the data determined from the in vitro and in vivo degradation studies. Uncrosslinked and DMS crosslinked collagen membranes were more susceptible to degradation by enzymes in vitro, while GTA-treated collagen was highly resistant to degradation. The biocompatibility of the collagen membranes was studied by subcutaneous implantation in rats. Uncrosslinked collagen membranes degraded within 14 days with the formation of granulation tissue. DMS crosslinked membranes degraded within 21 days and the area was replaced by numerous fibroblasts and newly formed collagen. No calcification was observed. For GTA-treated membranes, necrosis was observed after 7 days implantation and by 14 days the membrane had started to calcify. PMID:9294763

Charulatha, V; Rajaram, A

1997-09-15

414

Ocean color and atmospheric dimethyl sulfide: On their mesoscale variability  

NASA Technical Reports Server (NTRS)

The mesoscale variability of dimethyl sulfide (DMS) and ocean color is explored to determine the feasibility of a predictive relationship. During NASA's Global Tropospheric Experiment/Chemical Instrumentation Test and Evaluation (GTE/CITE 3), simultaneous shipboard and aircraft studies were carried out in the North Atlantic, followed by aircraft studies in the South Atlantic. Surface concentrations of chlorophyll alpha were measured with an airborne spectroradiometer, the Ocean Data Acquisition System (ODAS), with simultaneous determinations of tropospheric DMS. Shipboard measurements of DMS in air and water as well as in situ chlorophyll alpha were taken in the North Atlantic. No relation was observed between shipboard aquatic DMS and chlorophyll alpha or primary productivity. Higher levels of aqueous DMS were not always reflected by atmospheric DMS, although shipboard and aircraft measurements of atmospheric DMS agreed very well. A significant relationship between atmospheric DMS and ocean color was seen once at low altitudes in both the North and South Atlantic only under clean air conditions. Atmospheric DMS levels during the North Atlantic experiment were probably lowered by the presence of mostly polluted air masses in the study area and were, overall, probably not representative of the in situ sea-to-air flux of DMS. Changes in concentration of aircraft-sensed chlorophyllous pigments were not reflected by atmospheric DMS. If a predictive algorithm is to be found, phytoplankton blooms should probably be the first place to study an ocean color-DMS relationship.

Matrai, Patricia A.; Balch, William M.; Cooper, David J.; Saltzman, Eric S.

1993-01-01

415

Laboratory investigation of the atmospheric oxidation of dimethyl sulfide  

NASA Astrophysics Data System (ADS)

On a global scale dimethyl sulfide (DMS, CH3SCH3) is the largest natural source of reduced gas phase sulfur and this compound may play an important role in cloud and aerosol formation processes through its atmospheric oxidation products. Clouds and aerosol constitute a major component of the global climate system via the earth's radiation budget. The work comprising this dissertation entails kinetic, spectroscopic, and mechanistic studies of sulfur containing compounds that are key intermediates in the atmospheric oxidation of DMS. The goal of this dissertation is to improve the quantitative understanding of the DMS atmospheric oxidation mechanism through the determination of rate coefficients and product yields of important elementary gas phase reactions. The experimental approach employed utilized laser flash photolysis (LFP) to initiate free radical chemistry coupled with tune-resolved tunable diode laser spectroscopy (TDLAS) and/or time-resolved UV-VIS long path absorption spectroscopy (LPAS) to monitor the time dependent concentrations of reactants or products. Key reactions examined in this dissertation research include: OH + CH3S(O)CH3, CH3SCH2OO + CH 3SCH2OO, Cl- S(CH3)2+ O2/NO/NO 2. Chemical species monitored in the course of these studies include SO2, CH4, HCL CH2O, and CH3 by TDLAS and CH3OO and Cl-S(CH3)2 using UV-VIS absorption spectroscopy.

Urbanski, Shawn Peter

1999-11-01

416

High olfactory sensitivity for dimethyl sulphide in harbour seals.  

PubMed

Productive areas are patchily distributed at sea and represent important feeding grounds for many marine organisms. Although pinnipeds are known to travel on direct routes and return regularly to particular feeding sites, the environmental information seals use to perform this navigation is as yet unknown. As atmospheric dimethyl sulphide (DMS) has been demonstrated to be a reliable indicator for profitable foraging areas, we tested seals for their ability to smell DMS at concentrations typical for the marine environment. Using a go/no-go response paradigm we determined the DMS detection threshold in two harbour seals (Phoca vitulina vitulina). DMS stimuli from 8.05 x 108 to 8 pmol (DMS)m(-3)(air) were tested against a control stimulus using a custom-made olfactometer. DMS-thresholds determined for both seals (20 and 13 pmol m(-3)) indicate that seals can detect ambient concentrations associated with high primary productivity, e.g. in the North Atlantic. Thus, seals possess an extraordinarily high olfactory sensitivity for DMS, which could provide a sensory basis for identifying or orienting to profitable foraging grounds. PMID:17148339

Kowalewsky, Sylvia; Dambach, Martin; Mauck, Björn; Dehnhardt, Guido

2006-03-22

417

Recognition of asymmetrically dimethylated arginine by TDRD3  

PubMed Central

Asymmetric dimethylarginine (aDMA) marks are placed on histones and the C-terminal domain (CTD) of RNA Polymerase II (RNAP II) and serve as a signal for recruitment of appropriate transcription and processing factors in coordination with transcription cycle. In contrast to other Tudor domain-containing proteins, Tudor domain-containing protein 3 (TDRD3) associates selectively with the aDMA marks but not with other methylarginine motifs. Here, we report the solution structure of the Tudor domain of TDRD3 bound to the asymmetrically dimethylated CTD. The structure and mutational analysis provide a molecular basis for how TDRD3 recognizes the aDMA mark. The unique aromatic cavity of the TDRD3 Tudor domain with a tyrosine in position 566 creates a selectivity filter for the aDMA residue. Our work contributes to the understanding of substrate selectivity rules of the Tudor aromatic cavity, which is an important structural motif for reading of methylation marks. PMID:23066109

Sikorsky, Tomas; Hobor, Fruzsina; Krizanova, Eva; Pasulka, Josef; Kubicek, Karel; Stefl, Richard

2012-01-01

418

Biodegradation of diphenyl ether and its monohalogenated derivatives by Sphingomonas sp. strain SS3.  

PubMed Central

The bacterium Sphingomonas sp. strain SS3, which utilizes diphenyl ether and its 4-fluoro, 4-chloro, and (to a considerably lesser extent) 4-bromo derivatives as sole sources of carbon and energy, was enriched from soil samples of an industrial waste deposit. The bacterium showed cometabolic activities toward all other isomeric monohalogenated diphenyl ethers. During diphenyl ether degradation in batch culture experiments, phenol and catechol were produced as intermediates which were then channeled into the 3-oxoadipate pathway. The initial step in the degradation follows the recently discovered mechanism of 1,2-dioxygenation, which yields unstable phenolic hemiacetals from diphenyl ether structures. Oxidation of the structure-related dibenzo-p-dioxin yielded 2-(2-hydroxyphenoxy)-muconate upon ortho cleavage of the intermediate 2,2',3-trihydroxydiphenyl ether. Formation of phenol, catechol, halophenol, and halocatechol from the conversion of monohalogenated diphenyl ethers gives evidence for a nonspecific attack of the dioxygenating enzyme system. PMID:1444384

Schmidt, S; Wittich, R M; Erdmann, D; Wilkes, H; Francke, W; Fortnagel, P

1992-01-01

419

An efficient diethyl ether-based soxhlet protocol to quantify faecal sterols from catchment waters  

Microsoft Academic Search

A study was conducted to evaluate the efficiency and reproducibility of a diethyl ether-based soxhlet extraction procedure for faecal sterols occurring from catchment waters. Water samples spiked with a mixture of faecal sterols were filtered and analytes were extracted using the diethyl ether-based soxhlet method and the Bligh and Dyer chloroform extraction process. For diethyl ether-based soxhlet extraction procedure, solvent

Vikas Kumar G. Shah; Hugh Dunstan; Warren Taylor

2006-01-01

420

Evaluation of alternariol and alternariol methyl ether for mutagenic activity in Salmonella typhimurium  

SciTech Connect

Alternariol and alternariol methyl ether were tested in the Ames Salmonella typhimurium assay, and both were shown, with and without metabolic activation, to be nonmutagenic to strains TA98 and TA100. The finding of other investigators that alternariol methyl ether is weakly mutagenic to Ta98 without metabolic activation could have resulted from the presence of a small amount of one of the highly mutagenic altertoxins in the alternariol methyl ether originally tested. 9 refs., 3 figs., 1 tab.

Davis, V.M.; Stack, M.E. (Food and Drug Administration, Washington, DC (United States))

1994-10-01

421

Base mediated deprotection strategies for trifluoroethyl (TFE) ethers, a new alcohol protecting group  

PubMed Central

A trifluoroethyl (TFE) ether is specifically introduced as a protecting group in organic chemistry. Its first strategic application and removal in the total synthesis of vinigrol is discussed. Two lithium base mediated deprotection strategies for its removal are presented in this Letter. In one deprotection approach, the trifluoroethyl ether is converted to a difluorovinyl ether and then catalytically cleaved using osmium tetraoxide, while in the second approach a difluorovinyl anion is formed and trapped with an electrophilic oxygen reagent (MoOPH) to form a labile difluoroacetate. To further aid the reader, a summary of approaches for forming trifluoroethyl ethers is included as well as a discussion of alternate deprotection strategies. PMID:24391289

Yang, Qingliang; Njardarson, Jon T.

2013-01-01

422

Formation of Dimethyl Sulfide and Methanethiol in Anoxic Freshwater Sediments  

PubMed Central

Concentrations of volatile organic sulfur compounds (VOSC) were measured in water and sediment columns of ditches in a minerotrophic peatland in The Netherlands. VOSC, with methanethiol (4 to 40 nM) as the major compound, appeared to be mainly of sediment origin. Both VOSC and hydrogen sulfide concentrations decreased dramatically towards the water surface. High methanethiol and high dimethyl sulfide concentrations in the sediment and just above the sediment surface coincided with high concentrations of hydrogen sulfide (correlation factors, r = 0.91 and r = 0.81, respectively). Production and degradation of VOSC were studied in 32 sediment slurries collected from various freshwater systems in The Netherlands. Maximal endogenous methanethiol production rates of the sediments tested (up to 1.44 (mu)mol per liter of sediment slurry (middot) day(sup-1)) were determined after inhibition of methanogenic and sulfate-reducing populations in order to stop VOSC degradation. These experiments showed that the production and degradation of VOSC in sediments are well balanced. Statistical analysis revealed multiple relationships of methanethiol production rates with the combination of methane production rates (indicative of total anaerobic mineralization) and hydrogen sulfide concentrations (r = 0.90) or with the combination of methane production rates and the sulfate/iron ratios in the sediment (r = 0.82). These findings and the observed stimulation of methanethiol formation in sediment slurry incubations in which the hydrogen sulfide concentrations were artificially increased provided strong evidence that the anaerobic methylation of hydrogen sulfide is the main mechanism for VOSC formation in most freshwater systems. Methoxylated aromatic compounds are likely a major source of methyl groups for this methylation of hydrogen sulfide, since they are important degradation products of the abundant biopolymer lignin. Increased sulfate concentrations in several freshwater ecosystems caused by the inflow of water from the river Rhine into these systems result in higher hydrogen sulfide concentrations. As a consequence, higher fluxes of VOSC towards the atmosphere are conceivable. PMID:16535751

Lomans, B. P.; Smolders, A.; Intven, L. M.; Pol, A.; Op, De; Van Der Drift, C.

1997-01-01

423

Formation of dimethyl sulfide and methanethiol in anoxic freshwater sediments.  

PubMed

Concentrations of volatile organic sulfur compounds (VOSC) were measured in water and sediment columns of ditches in a minerotrophic peatland in The Netherlands. VOSC, with methanethiol (4 to 40 nM) as the major compound, appeared to be mainly of sediment origin. Both VOSC and hydrogen sulfide concentrations decreased dramatically towards the water surface. High methanethiol and high dimethyl sulfide concentrations in the sediment and just above the sediment surface coincided with high concentrations of hydrogen sulfide (correlation factors, r = 0.91 and r = 0.81, respectively). Production and degradation of VOSC were studied in 32 sediment slurries collected from various freshwater systems in The Netherlands. Maximal endogenous methanethiol production rates of the sediments tested (up to 1.44 (mu)mol per liter of sediment slurry (middot) day(sup-1)) were determined after inhibition of methanogenic and sulfate-reducing populations in order to stop VOSC degradation. These experiments showed that the production and degradation of VOSC in sediments are well balanced. Statistical analysis revealed multiple relationships of methanethiol production rates with the combination of methane production rates (indicative of total anaerobic mineralization) and hydrogen sulfide concentrations (r = 0.90) or with the combination of methane production rates and the sulfate/iron ratios in the sediment (r = 0.82). These findings and the observed stimulation of methanethiol formation in sediment slurry incubations in which the hydrogen sulfide concentrations were artificially increased provided strong evidence that the anaerobic methylation of hydrogen sulfide is the main mechanism for VOSC formation in most freshwater systems. Methoxylated aromatic compounds are likely a major source of methyl groups for this methylation of hydrogen sulfide, since they are important degradation products of the abundant biopolymer lignin. Increased sulfate concentrations in several freshwater ecosystems caused by the inflow of water from the river Rhine into these systems result in higher hydrogen sulfide concentrations. As a consequence, higher fluxes of VOSC towards the atmosphere are conceivable. PMID:16535751

Lomans, B P; Smolders, A; Intven, L M; Pol, A; Op, D; Van Der Drift, C

1997-12-01

424

Control of organo-sulfur emissions using biofiltration: Dimethyl sulfide  

SciTech Connect

Laboratory-scale experiments were conducted to evaluate the removal of dimethyl sulfide (DMS) in both upflow and downflow compost biofilter columns. Gas flow rates and DMS concentrations were varied to study their effects on removal efficiency. The kinetic dependence of DMS removal along the column length was also examined to obtain a quantitative description of pollutant removal. In addition, important operating parameters, such as filter bed pH and water content, as well as gas retention time, were observed throughout the experiments. The maximum pollutant loading rates for the compost filters were found to be 5.2 and 5.5 g-DMS/m{sup 3}/hr for the upflow and downflow biofilter columns, respectively. Removal efficiencies were high (> 95%) for inlet concentrations up to 15 ppm DMS and 30 second empty-bed residence times, or 19 ppm DMS for 45 second residence times. Removal efficiencies remained high (> 95%) for DMS concentrations up to 27 ppm for 60 second residence times. DMS removal rates through the biofilter columns appear to follow fractional-order diffusion-limited macrokinetics. The average macrokinetic rate coefficient for the upflow column was 0.0789 {+-} 0.0178 ppm{sup 1/2}/sec. The average rate coefficient for the downflow column was 0.0935 {+-}0.0200 ppm{sup 1/2}/sec. The biofilter columns were periodically washed to remove sulfuric acid, which is formed as an end-product of the biological degradation of DMS, and to replenish the moisture content of the filter material. It was found that the downflow column benefitted greatly by regular washing with alkaline washwater, while the upflow column operated well with non-alkaline water washing.

Kong, S.; Allen, E.R. [Univ. of Florida, Gainesville, FL (United States). Dept. of Environmental Engineering Sciences

1997-12-31

425

An AP Endonuclease Functions in Active DNA Dimethylation and Gene Imprinting in Arabidopsis.  

PubMed

Active DNA demethylation in plants occurs through base excision repair, beginning with removal of methylated cytosine by the ROS1/DME subfamily of 5-methylcytosine DNA glycosylases. Active DNA demethylation in animals requires the DNA glycosylase TDG or MBD4, which functions after oxidation or deamination of 5-methylcytosine, respectively. However, little is known about the steps following DNA glycosylase action in the active DNA demethylation pathways in plants and animals. We show here that the Arabidopsis APE1L protein has apurinic/apyrimidinic endonuclease activities and functions downstream of ROS1 and DME. APE1L and ROS1 interact in vitro and co-localize in vivo. Whole genome bisulfite sequencing of ape1l mutant plants revealed widespread alterations in DNA methylation. We show that the ape1l/zdp double mutant displays embryonic lethality. Notably, the ape1l+/-zdp-/- mutant shows a maternal-effect lethality phenotype. APE1L and the DNA phosphatase ZDP are required for FWA and MEA gene imprinting in the endosperm and are important for seed development. Thus, APE1L is a new component of the active DNA demethylation pathway and, together with ZDP, regulates gene imprinting in Arabidopsis. PMID:25569774

Li, Yan; Córdoba-Cañero, Dolores; Qian, Weiqiang; Zhu, Xiaohong; Tang, Kai; Zhang, Huiming; Ariza, Rafael R; Roldán-Arjona, Teresa; Zhu, Jian-Kang

2015-01-01

426

An AP Endonuclease Functions in Active DNA Dimethylation and Gene Imprinting in Arabidopsis  

PubMed Central

Active DNA demethylation in plants occurs through base excision repair, beginning with removal of methylated cytosine by the ROS1/DME subfamily of 5-methylcytosine DNA glycosylases. Active DNA demethylation in animals requires the DNA glycosylase TDG or MBD4, which functions after oxidation or deamination of 5-methylcytosine, respectively. However, little is known about the steps following DNA glycosylase action in the active DNA demethylation pathways in plants and animals. We show here that the Arabidopsis APE1L protein has apurinic/apyrimidinic endonuclease activities and functions downstream of ROS1 and DME. APE1L and ROS1 interact in vitro and co-localize in vivo. Whole genome bisulfite sequencing of ape1l mutant plants revealed widespread alterations in DNA methylation. We show that the ape1l/zdp double mutant displays embryonic lethality. Notably, the ape1l+/?zdp?/? mutant shows a maternal-effect lethality phenotype. APE1L and the DNA phosphatase ZDP are required for FWA and MEA gene imprinting in the endosperm and are important for seed development. Thus, APE1L is a new component of the active DNA demethylation pathway and, together with ZDP, regulates gene imprinting in Arabidopsis. PMID:25569774

Li, Yan; Córdoba-Cañero, Dolores; Qian, Weiqiang; Zhu, Xiaohong; Tang, Kai; Zhang, Huiming; Ariza, Rafael R.; Roldán-Arjona, Teresa; Zhu, Jian-Kang

2015-01-01

427

40 CFR 721.10398 - Poly(oxy-1,2-ethanediyl),. alpha., -monoalkyl ethers-.omega.-mono (hydrogen maleate)- (generic).  

Code of Federal Regulations, 2014 CFR

...monoalkyl ethers-.omega.-mono (hydrogen maleate)- (generic). 721.10398...monoalkyl ethers-.omega.-mono (hydrogen maleate)- (generic). (a) Chemical...monoalkyl ethers-.omega.-mono (hydrogen maleate)- (PMN P-10-495)...

2014-07-01

428

40 CFR 721.10398 - Poly(oxy-1,2-ethanediyl),. alpha., -monoalkyl ethers-.omega.-mono (hydrogen maleate)- (generic).  

Code of Federal Regulations, 2013 CFR

...monoalkyl ethers-.omega.-mono (hydrogen maleate)- (generic). 721.10398...monoalkyl ethers-.omega.-mono (hydrogen maleate)- (generic). (a) Chemical...monoalkyl ethers-.omega.-mono (hydrogen maleate)- (PMN P-10-495)...

2013-07-01

429

40 CFR 721.10398 - Poly(oxy-1,2-ethanediyl),. alpha., -monoalkyl ethers-.omega.-mono (hydrogen maleate)- (generic).  

Code of Federal Regulations, 2012 CFR

...monoalkyl ethers-.omega.-mono (hydrogen maleate)- (generic). 721.10398...monoalkyl ethers-.omega.-mono (hydrogen maleate)- (generic). (a) Chemical...monoalkyl ethers-.omega.-mono (hydrogen maleate)- (PMN P-10-495)...

2012-07-01

430

Two crown-ether-coordinated caesium halogen salts.  

PubMed

The crystal structures of two crown-ether-coordinated caesium halogen salt hydrates, namely di-?-bromido-bis[aqua(1,4,7,10,13,16-hexaoxacyclooctadecane)caesium(I)] dihydrate, [Cs2Br2(C12H24O6)2(H2O)2]·2H2O, (I), and poly[[diaquadi-?-chlorido-?-(1,4,7,10,13,16-hexaoxacyclooctadecane)dicaesium(I)] dihydrate], {[Cs2Cl2(C12H24O6)(H2O)2]·2H2O}n, (II), are reported. In (I), all atoms are located on general positions. In (II), the Cs(+) cation is located on a mirror plane perpendicular to the a axis, the chloride anion is located on a mirror plane perpendicular to the c axis and the crown-ether ring is located around a special position with site symmetry 2/m, with two opposite O atoms exactly on the mirror plane perpendicular to the a axis; of one water molecule, only the O atom is located on a mirror plane perpendicular on the a axis, while the other water molecule is completely located on a mirror plane perpendicular to the c axis. Whereas in (I), hydrogen bonds between bromide ligands and water molecules lead to one-dimensional chains running along the b axis, in (II) two-dimensional sheets of water molecules and chloride ligands are formed which combine with the polymeric caesium-crown polymer to give a three-dimensional network. Although both compounds have a similar composition, i.e. a Cs(+) cation with a halogen, an 18-crown-6 ether and a water ligand, the crystal structures are rather different. On the other hand, it is remarkable that (I) is isomorphous with the already published iodide compound. PMID:24816013

Well, Natalija van; Klein, Christian; Ritter, Franz; Assmus, Wolf; Krellner, Cornelius; Bolte, Michael

2014-05-01

431

Specular lithium deposits from lithium hexafluoroarsenate/diethyl ether electrolytes  

SciTech Connect

A new class of aprotic organic electrolytes in which to cycle the lithium electrode has been developed. Blends of diethyl ether (DEE) and tetrahydrofuran (THF) incorporating LiAsF/sub 6/ have been found to afford Li electrode cycling efficiencies in excess of 98%. In addition, specular deposits of up to 10 C/cm/sup 2/ may be plated from these systems. The kinetic stability of these blended electrolytes toward Li is thought to be due to the formation of a protective lithium ethoxide film. 15 refs.

Koch, V.R.; Goldman, J.L.; Mattos, C.J.; Mulvaney, M.

1982-01-01

432

The Search for a Complex Molecule in a Selected Hot Core Region: A Rigorous Attempt to Confirm trans-Ethyl Methyl Ether toward W51 e1/e2  

E-print Network

An extensive search has been conducted to confirm transitions of \\textit{trans}-ethyl methyl ether (tEME, C$_2$H$_5$OCH$_3$), toward the high mass star forming region W51 e1/e2 using the 12 m Telescope of the Arizona Radio Observatory (ARO) at wavelengths from 2 mm and 3 mm. In short, we cannot confirm the detection of tEME toward W51 e1/e2 and our results call into question the initial identification of this species by \\citet{FuchsSpace}. Additionally, reevaluation of the data from the original detection indicates that tEME is not present toward W51 e1/e2 in the abundance reported by Fuchs and colleagues. Typical peak-to-peak noise levels for the present observations of W51 e1/e2 were between 10 - 30 mK, yielding an upper limit of the tEME column density of $\\leq$ 1.5 $\\times$ 10$^{15}$ cm$^{-2}$. This would make tEME at least a factor 2 times less abundant than dimethyl ether (CH$_3$OCH$_3$) toward W51 e1/e2. We also performed an extensive search for this species toward the high mass star forming region Sgr...

Carroll, P Brandon; Blake, Geoffrey A; Apponi, A J; Ziuyrs, L M; Remijan, Anthony

2014-01-01

433

Zero-electron-kinetic-energy photoelectron spectroscopy of transition-metal--ether complexes: Y-O(CH3)2, Y-O(CD3)2, Y-O(CH3)22, and Y-[O(CD3)2]2  

NASA Astrophysics Data System (ADS)

The yttrium complexes with one and two dimethyl ethers and their deuterated derivatives are prepared with laser vaporization molecular beam techniques, identified with photoionization time-of-flight mass spectrometry, and investigated with pulsed-field-ionization zero-electronkinetic-energy (ZEKE) photoelectron spectroscopy and ab initio calculations. Adiabatic ionization potentials and yttrium-oxygen stretch and ether-based vibrations are measured for the 1:1 and 1:2 complexes. Fermi interactions are observed from the ZEKE spectra of the 1:1 species. The ground electronic states of the monoligand complexes are determined to be 2A2 for the neutral and 1A1 for the singly charged positive ion, both in C2v symmetry, with yttrium binding to oxygen. The coordination of a second ether forms a diligand complex with a linear oxygen-yttrium-oxygen configuration. This is the first electronic-vibrational spectroscopic study of yttrium-polyatomic molecule complexes and weakly bound metal complexes with two or more polyatomic molecules.

Rothschopf, Gretchen K.; Li, Shenggang; Yang, Dong-Sheng

2002-11-01

434

Electron transfer as the initiation mechanism of photocurable maleimide–vinyl ether based resins  

Microsoft Academic Search

Maleimide–vinyl ether resins polymerise upon UV irradiation without the addition of a photoinitiator. The first step of initiation is an electron transfer from a ground state vinyl ether molecule to the triplet maleimide. Absolute rate constants for the reaction of triplet maleimide (?max=260 and 320 nm) with maleimide itself, unsaturated monomers, inorganic ions, and alcohols were determined by laser flash photolysis.

Justus von Sonntag; Dieter Beckert; Wolfgang Knolle; Reiner Mehnert

1999-01-01

435

AN EVALUATION OF THE HUMAN CARCINOGENIC POTENTIAL OF ETHYLENE GLYCOL BUTYL ETHER: INTERIM FINAL POSITION PAPER  

EPA Science Inventory

In order to determine the merit of a petition to remove ethylene glycol ether (EGBE) from the Agency's Hazardous Air Pollutant (HAP) list, EPA has developed an interim final position paper, An Evaluation of the Human Carcinogenic Potential of Ethylene Glycol Butyl Ether, t...

436

Construction of supramolecular organogels and hydrogels from crown ether based unsymmetric bolaamphiphiles.  

PubMed

A bolaamphiphilic low-molecular-weight gelator based on crown ether, which could self-assemble into organogels and hydrogels, was prepared. The contribution of each part of the structure to the gelation property was investigated by designing a series of analogues. A simple framework (crown ether-hydrophobic linkage-ammonium salt) was proposed. PMID:25174940

Gao, Lingyan; Xu, Donghua; Zheng, Bo

2014-10-18

437

SOLUTION EFFECTS ON CESIUM COMPLEXATION WITH CALIXARENE CROWN ETHERS FROM LIQUID TO SUPERCRITICAL FLUIDS  

EPA Science Inventory

Calixarene-crown ethers with rigid skeletons are superior to flexible crown ethers for separation of 137Cs from high level waste (HLW). However, this extraction methodology often requires undesirable solvents and the extraction efficiency is strongly dependent on the solvent pol...

438

Extraction of Strontium and Cesium by Dicarbollides, Crown Ethers and Functionalized Calixarenes  

Microsoft Academic Search

The two main classes of extractantsused for the extraction of cesium and strontium aredicarbollides and crown ethers. Dicarbollides wereused on a large scale for the extraction of these twoelements from high-activity waste. The basicdicarbollides present drawbacks since they need to bediluted in polar solvent such as nitrobenzene and theirefficiency strongly decreases as the acidity of liquidwaste increases. Crown ethers enable

J. F. Dozol; M. Dozol; R. M. Macias

2000-01-01

439

Alkaline stability of cellulose ethers and impact of their degradation products on cement hydration  

E-print Network

1 Alkaline stability of cellulose ethers and impact of their degradation products on cement-mail address: pourchez@emse.fr emse-00449712,version1-18Sep2010 Author manuscript, published in "Cement the potential role of cellulose ethers degradation on the alteration of the cement hydration kinetics

Paris-Sud XI, Université de

440

Ether sulfones with additives for electrolytes in rechargeable lithium ion batteries  

E-print Network

Ether sulfones with additives for electrolytes in rechargeable lithium ion batteries Xiao-Guang Sun in rechargeable lithium ion battery [1-5]. In a previous publication [6] we described a series of ether sulfones electrolyte interface (SEI) needed for the long battery cycle life, they are limited in their commercial

Angell, C. Austen

441

Synthesis of imide/arylene ether copolymers for adhesives and composite matrices  

NASA Technical Reports Server (NTRS)

A series of imide/arylene ether copolymers were prepared from the reaction of an amorphous arylene ether oligomer and a semi-crystalline imide oligomer. These copolymers were thermally characterized and mechanical properties were measured. One block copolymer was endcapped and the molecular weight was controlled to provide a material that displayed good compression moldability and attractive adhesion and composite properties.

Jensen, B. J.; Hergenrother, P. M.; Bass, R. G.

1991-01-01

442

IRON(III) NITRATE-CATALYZED FACILE SYNTHESIS OF DIPHENYLMETHYL (DPM) ETHERS FROM ALCOHOLS  

EPA Science Inventory

Diphenyl methyl (DPM) ethers constitute important structural portion of some pharmaceutical entities and also as protective group for hydroxyl groups in synthetic chemistry. DPM ethers are normally prepared using concentrated acids or base as catalysts, which may result in the fo...

443

Enzymes and genes involved in the aerobic biodegradation of methyl tert -butyl ether (MTBE)  

Microsoft Academic Search

Fuel oxygenates, mainly methyl tert-butyl ether (MTBE) but also ethyl tert-butyl ether (ETBE), are added to gasoline in replacement of lead tetraethyl to enhance its octane index. Their addition also improves the combustion efficiency and therefore decreases the emission of pollutants (CO and hydrocarbons). On the other hand, MTBE, being highly soluble in water and recalcitrant to biodegradation, is a

Nicolas Lopes Ferreira; Cédric Malandain; Françoise Fayolle-Guichard

2006-01-01

444

Gallium and Indium Complexes for Ring-Opening Polymerization of Cyclic Ethers, Esters and Carbonates  

E-print Network

1 Gallium and Indium Complexes for Ring-Opening Polymerization of Cyclic Ethers, Esters-francois.carpentier@univ-rennes1.fr Contents 1. Introduction 2. Gallium-based initiators/catalysts for the ROP of cyclic ethers, esters and carbonates: synthesis, characterization and catalytic performance 2.1. Gallium complexes

Paris-Sud XI, Université de

445

Bioavailability of decabromodiphenyl ether to the marine polychaete Nereis virens.  

PubMed

The flame retardant decabromodiphenyl ether (BDE 209) accumulates in humans and terrestrial food webs, but few studies have reported the accumulation of BDE 209 in aquatic biota. To investigate the mechanisms controlling the bioavailability of BDE 209, a 28-d bioaccumulation experiment was conducted in which the marine polychaete worm Nereis virens was exposed to a decabromodiphenyl ether (deca-BDE) commercial mixture (>85% BDE 209) in spiked sediments, in spiked food, or in field sediments. Bioaccumulation from spiked substrate with maximum bioavailability demonstrated that BDE 209 accumulates in this species. Bioavailability depends on the exposure conditions, however, because BDE 209 in field sediments did not accumulate (<0.3 ng/g wet weight; 28-d biota-sediment accumulation factors [BSAFs] <0.001). When exposed to deca-BDE in spiked sediments also containing lower brominated congeners (a penta-BDE mixture), bioaccumulation of BDE 209 was 30 times lower than when exposed to deca-BDE alone. Selective accumulation of the lower brominated congeners supports their prevalence in higher trophic level species. The mechanisms responsible for limited accumulation of BDE 209 may involve characteristics of the sediment matrix and low transfer efficiency in the digestive fluid. PMID:20821515

Klosterhaus, Susan L; Baker, Joel E

2010-04-01

446

Vibrational spectra of guaiacylglycerol-?-guaiacyl ether: Experiment and theory.  

PubMed

As an important inter-unit of lignin, guaiacylglycerol-?-guaiacyl (GG) ether has been synthesized, and characterized using terahertz time-domain spectroscopy in the frequency range of 5-85cm(-1). Seven absorption peaks have been observed. Among these peaks, the 49.8cm(-1) and 57.6cm(-1) vibrations are propose to be characteristic absorption peaks of GG ether. Raman spectra were also measured in the range of 50-3500cm(-1). The vibrations of the two lowest energy forms, i.e., erythro 1r4s and threo 1s4s, were calculated using density functional theory at the B3LYP/6-311G(??) level and assigned according to potential energy distribution. In addition, the contents of erythro and threo forms in GG sample could be estimated by comparing the waveform similarities between theoretical and observed curves in the 33.0-80.0cm(-1) range. Results showed that the observed curve of GG sample is a combination of erythro 1s4r and threo 1s4s. The four absorption vibrations below 33.0cm(-1) could be assigned to phonon, inter-molecular modes and/or hydrogen bond vibrations. Terahertz spectra and Raman spectra, together with theoretical calculations, could be powerful methods for predicting contents of different isomers in sample. PMID:25576943

Su, Tong-Fu; Huang, Rong; Su, Ya-Qiong; Zhao, Guo-Zhong; Wu, De-Yin; Wang, Jian-An; Gong, Chang-Rong; Xu, Cui-Lian

2015-03-15

447

Novel Ordered Crown Ether-Containing Polyimides for Ion Conduction  

NASA Technical Reports Server (NTRS)

We report the synthesis and characterization of thermally-stable polyimides for use as battery and fuel cell electrolyte membranes. Dianhydrides used were 1,4,5,8- naphthalenetetracarboxylic dianhydride and/or 4,4'-(hexafluoroisopropylidene)diphthalic anhydride. Diamines used were anti-4,4-diaminodibenzo-l8-crown-6, 4,4'- diaminodibenzo-24-crown-8, 2,2-bis(4-aminophenyl)hexafluoropropane, and/or 2,5- diaminobenzenesulfonic acid. The polymers were characterized using electrochemical impedance spectroscopy (EIS), thermal analysis and X-ray diffraction. Polymers containing the hexafluoroisopropylidene (HFIP) group were soluble in common organic solvents, while polymers without the HFIP group were very poorly soluble. Sulfonation yields polymers that are sparingly soluble in aqueous base and/or methanol. Degree of sulfonation, determined by titration, was between one and three sulfonate groups per repeat unit. Proton conductivity was determined as a function of water content, with a maximum conductivity of l x 10(exp -2) per centimeter when fully hydrated. Crown ether-containing polymers exhibit a high degree of order that may be indicative of crown ether channel formation, which may facilitate Li(+) transport for use in battery membranes.

Irvin, Jennifer A.; Stasko, Daniel; Fallis, Stephen; Guenthner, Andrew J.; Webber, Cynthia; Blackwell, John; Chvalun, Sergei N.

2003-01-01

448

Developmental toxicity of diphenyl ether herbicides in nestling American kestrels  

USGS Publications Warehouse

Beginning the day after hatching, American kestrel (Falco sparverius) nestlings were orally dosed for 10 consecutive days with 5 microliters/g of corn oil (controls) or one of the diphenyl ether herbicides (nitrofen, bifenox, or oxyfluorfen) at concentrations of 10, 50, 250, or 500 mg/kg in corn oil. At 500 mg/kg, nitrofen resulted in complete nestling mortality, bifenox in high (66%) mortality, and oxyfluorfen in no mortality. Nitrofen at 250 mg/kg reduced nestling growth as reflected by decreased body weight, crownrump length, and bone lengths including humerus, radiusulna, femur, and tibiotarsus. Bifenox at 250 mg/kg had less effect on growth than nitrofen, but crownrump, humerus, radiusulna, and femur were significantly shorter than controls. Liver weight as a percent of body weight increased with 50 and 250 mg/kg nitrofen. Other manifestations of impending hepatotoxicity following nitrofen ingestion included increased hepatic GSH peroxidase activity in all nitrofentreated groups, and increased plasma enzyme activities for ALT, AST, and LDHL in the 250mg/kg group. Bifenox ingestion resulted in increased hepatic GSH peroxidase activity in the 50and 250mg/kg groups. Nitrofen exposure also resulted in an increase in total plasma thyroxine (T4) concentration. These findings suggest that altricial nestlings are more sensitive to diphenyl ether herbicides than young or adult birds of precocial species.

Hoffman, D.J.; Spann, J.W.; LeCaptain, L.J.; Bunck, C.M.; Rattner, B.A.

1991-01-01

449

Synthesis of hydroxy thio-ether derivatives of vegetable oil.  

PubMed

Bio-based additives are desirable commodities due to their eco-friendly nature. These additives can demonstrate physical and chemical properties comparable to those of conventional mineral oil-based products. Sulfur incorporated triacylglycerol can function as an antiwear/antifriction additive for lubricants. The synthesis of four useful hydroxy thio-ether derivatives of vegetable oils, from commercially available epoxidized soybean oil and common organic thiols, is reported in this paper. The common thiols used herein were 1-butanethiol, 1-decanethiol, 1-octadecanethiol, and cyclohexyl mercaptan. Currently, there is no reported literature describing the synthesis of hydroxy thio-ether derivatives of vegetable oil. The reaction was monitored, and products were confirmed by NMR and FTIR spectroscopies. Experimental conditions involving various thiols, solvent, catalyst amount, time, and temperature were optimized for research quantity and laboratory scale-up. The synthetic process retains the vegetable oil structure, eliminates polyunsaturation in the molecule, and adds polar functional groups on triacylglycerol. These products can be used as agriculturally-based antiwear additives for lubricant applications. PMID:17177513

Sharma, Brajendra K; Adhvaryu, A; Erhan, S Z

2006-12-27

450

Ether-Bond-Containing Ionic Liquids as Supercapacitor Electrolytes  

PubMed Central

Electrochemical capacitors (ECs) are electrical energy storage devices that have the potential to be very useful in a wide range of applications, especially where there is a large disparity between peak and average power demands. The use of ionic liquids (ILs) as electrolytes in ECs can increase the energy density of devices; however, the viscosity and conductivity of ILs adversely influence the power density of the device. We present experimental results where several ILs containing different cations have been employed as the electrolyte in cells containing mesoporous carbon electrodes. Specifically, the behavior of ILs containing an ether bond in an alkyl side chain are compared with those of a similar structure and size but containing purely alkyl side chains. Using electrochemical impedance spectroscopy and constant current cycling, we show that the presence of the ether bond can dramatically increase the specific capacitance and reduce device resistance. These results have the important implication that such ILs can be used to tailor the physical properties and electrochemical performance of IL-based electrolytes. PMID:24920995

2013-01-01

451

Synthesis and antiprotozoal activities of benzyl phenyl ether diamidine derivatives.  

PubMed

Sixty-two cationic benzyl phenyl ether derivatives (36 amidines and 26 prodrugs) were prepared and assayed for activities in vitro and in vivo against Trypanosoma brucei rhodesiense (STIB900), and in vitro against Plasmodium falciparum (K1) and Leishmania donovani axenic amastigotes. 3-Amidinobenzyl 4-amidino-2-iodo-6-methoxyphenyl ether dihydrochloride (55, IC50 = 3.0 nM) and seven other compounds exhibited IC50 values below 10 nM against T. b. rhodesiense in vitro. The 2-bromo-4,4'-diamidino analogue 19 (IC50 = 4.0 nM) and 12 other analogues were more potent than pentamidine (IC50 = 46 nM) against P. falciparum. The 3',4-diamidino-2,6-diiodo analogue 49 (IC50 = 1.4 ?M) and two other compounds were more effective than pentamidine (IC50 = 1.8 ?M) against L. donovani. A prodrug, 3',4-bis(N?-methoxy)amidino-2-bromo derivative 38, was the most efficacious against trypanosome infected mice, attaining 4/4 cures in four daily 25 mg/kg oral doses, and the 2-chloro-4,4'-diamidine 18 cured 3/4 mice in four daily 5 mg/kg intraperitoneal doses. PMID:23871911

Patrick, Donald A; Bakunov, Stanislav A; Bakunova, Svetlana M; Jones, Susan Kilgore; Wenzler, Tanja; Barszcz, Todd; Kumar, Arvind; Boykin, David W; Werbovetz, Karl A; Brun, Reto; Tidwell, Richard R

2013-09-01

452

Aerobic biotransformation of polybrominated diphenyl ethers (PBDEs) by bacterial isolates  

PubMed Central

Polybrominated diphenyl ethers (PBDEs) are flame retardants that have been used in consumer products and furniture for three decades. Currently, very little is known about their fate in the environment and specifically about their susceptibility to aerobic biotransformation. Here, we investigated the ability of the polychlorinated biphenyl (PCB) degrading bacteria Rhodococcus jostii RHA1 and Burkholderia xenovorans LB400 to transform mono- through hexa-BDEs at ppb levels. We also tested the PBDE transforming abilities of related strain Rhodococcus sp. RR1 and the ether-degrading Pseudonocardia dioxanivorans CB1190. The two PCB-degrading strains transformed all of the mono- through penta-BDEs and strain LB400 transformed one of the hexa-BDEs. The extent of transformation was inversely proportional to the degree of bromination. Strains RR1 and CB1190 were only able to transform the less brominated mono- and di- BDE congeners. RHA1 released stoichiometric quantities of bromide while transforming mono- and tetra-BDE congeners. LB400 instead converted most of a mono-BDE to a hydroxylated mono-BDE. This is the first report of aerobic transformation of tetra-, penta- and hexa-BDEs as well as the first report of stoichiometric release of bromide during PBDE transformation. PMID:19731666

Robrock, Kristin R.; Coelhan, Mehmet; Sedlak, David; Alvarez-Cohen, Lisa

2009-01-01

453

Metabolic Fingerprint of Dimethyl Sulfone (DMSO2) in Microbial-Mammalian Co-metabolism.  

PubMed

There is growing awareness that intestinal microbiota alters the energy harvesting capacity of the host and regulates metabolism. It has been postulated that intestinal microbiota are able to degrade unabsorbed dietary components and transform xenobiotic compounds. The resulting microbial metabolites derived from the gastrointestinal tract can potentially enter the circulation system, which, in turn, affects host metabolism. Yet, the metabolic capacity of intestinal microbiota and its interaction with mammalian metabolism remains largely unexplored. Here, we review a metabolic pathway that integrates the microbial catabolism of methionine with mammalian metabolism of methanethiol (MT), dimethyl sulfide (DMS), and dimethyl sulfoxide (DMSO), which together provide evidence that supports the microbial origin of dimethyl sulfone (DMSO2) in the human metabolome. Understanding the pathway of DMSO2 co-metabolism expends our knowledge of microbial-derived metabolites and motivates future metabolomics-based studies on ascertaining the metabolic consequences of intestinal microbiota on human health, including detoxification processes and sulfur xenobiotic metabolism. PMID:25245235

He, Xuan; Slupsky, Carolyn M

2014-12-01

454

Characterization and performance of proton exchange membranes for direct methanol fuel cell: Blending of sulfonated poly(ether ether ketone) with charged surface modifying macromolecule  

Microsoft Academic Search

Modification of sulfonated poly(ether ether ketone) (SPEEK) membrane was attempted by blending charged surface modifying macromolecule (cSMM). The modified membrane was tested for direct methanol fuel cell (DMFC) application; i.e. a SPEEK\\/cSMM blend membrane was compared to a SPEEK membrane and a Nafion 112 membrane for the thermal and mechanical stability, methanol permeability, and proton conductivity. Thermal and mechanical stability

M. N. A. Mohd Norddin; A. F. Ismail; D. Rana; T. Matsuura; A. Mustafa; A. Tabe-Mohammadi

2008-01-01

455

Assignment of 13C NMR chemical shift and microstructure of copolymers of 2-chloroethyl vinyl ether-maleic anhydride and n-butyl vinyl ether-maleic anhydride  

Microsoft Academic Search

Summary  \\u000a The chemical shift in the 13C NMR spectra of copolymers of 2-chloroethyl vinyl ether (CEVE) and maleic anhydride (MA), and of n-butyl vinyl ether (BVE)\\u000a and MA is assigned. It is found that both copolymers are made of completely alternating monomer unit sequences and that the\\u000a proportion of cis linkage configuration at the cyclic MA units is 45 %

Nguyen T. H. Ha; Kiyohisa Fujimori; Peter C. Henry; David J. Tucker

1999-01-01

456

High-pressure liquid chromatography: A brief introduction and its application in analyzing the degradation of a C-ether (Thio-ether) liquid lubricant  

NASA Technical Reports Server (NTRS)

The general principles of classical liquid chromatography and high pressure liquid chromatography (HPLC) are reviewed, and their advantages and disadvantages are compared. Several chromatographic techniques are reviewed, and the analytical separation of a C-ether liquid lubricant by each technique is illustrated. A practical application of HPLC is then demonstrated by analyzing a degraded C-ether liquid lubricant from full scale, high temperature bearing tests.

1983-01-01

457

Absolute configuration of arylglycerol- ? -aryl ethers obtained by asymmetric reduction of the corresponding ? -ketonic compound with intact Fusarium solani cells  

Microsoft Academic Search

When (±)-?-oxo-guaiacylglycerol-?-(vanillic acid) ether (1) is degraded byFusarium solani M-13-1, the?-ketone is initially reduced to giveerythro andthreo guaiacylglycerol-?-(vanillic acid) ethers (2), arylglycerol-?-aryl ethers, both of which are enantiomerically pure. The absolute configuration in each2 was determined by Mosher's method; the products were converted to?,?-di-(R)-?-methoxy-?-trifluoromethylphenylacetates (MTPA esters) (3?) oferythro (-)- andthreo (+)-veratrylglycerol-?-(methyl vanillate) ethers (3), whose1H nuclear magnetic resonance (NMR) spectra

Takeshi Katayama; Jyoji Tsutsui; Kazuo Tsueda; Takao Miki; Yasuhiro Yamada; Murao Sogo

2000-01-01

458

Boundary lubrication of formulated C-ethers in air to 300 C. 2: Organic acid additives  

NASA Technical Reports Server (NTRS)

Friction and wear measurements were made on CVM M-50 steel lubricated with three C-ether (modified polyphenyl ether) formulations in dry and moist air. Results were compared to those obtained with a formulated Type 2 ester and the C-ether base fluid. A ball-on-disk sliding friction apparatus was used. Experimental conditions were a 1-kilogram load, a 17-meter/minute surface speed, and a 25 to 300 C (77 to 572 F) disk temperature range. The three C-ether formulations yielded better boundary lubricating characteristics than the Type 2 ester under most test conditions. All C-ether formulations exhibited higher friction coefficients than the ester from 150 to 300 C (302 to 572 F) and similar or lower values from 25 to 150 C (77 to 302 F).

Jones, W. R., Jr.

1973-01-01

459

Degradation of Perfluorinated Ether Lubricants on Pure Aluminum Surfaces: Semiempirical Quantum Chemical Modeling  

NASA Technical Reports Server (NTRS)

The AM1 semiempirical quantum chemical method was used to model the interaction of perfluoroethers with aluminum surfaces. Perfluorodimethoxymethane and perfluorodimethyl ether were studied interacting with aluminum surfaces, which were modeled by a five-atom cluster and a nine-atom cluster. Interactions were studied for edge (high index) sites and top (low index) sites of the clusters. Both dissociative binding and nondissociative binding were found, with dissociative binding being stronger. The two different ethers bound and dissociated on the clusters in different ways: perfluorodimethoxymethane through its oxygen atoms, but perfluorodimethyl ether through its fluorine atoms. The acetal linkage of perfluorodimeth-oxymethane was the key structural feature of this molecule in its binding and dissociation on the aluminum surface models. The high-index sites of the clusters caused the dissociation of both ethers. These results are consistent with the experimental observation that perfluorinated ethers decompose in contact with sputtered aluminum surfaces.

Slaby, Scott M.; Ewing, David W.; Zehe, Michael J.

1997-01-01

460

A Theoretical Investigation of Dimethyl Carbonate Synthesis on Cu-Y Zeolite Xiaobo Zheng and Alexis T. Bell*  

E-print Network

A Theoretical Investigation of Dimethyl Carbonate Synthesis on Cu-Y Zeolite Xiaobo Zheng and Alexis of dimethyl carbonate (DMC) synthesis via oxidative carbonylation of methanol on Cu-exchanged Y zeolite, Cu-3 Cu-exchanged zeolite are known to be active catalysts for oxidative carbonylation of methanol

Bell, Alexis T.

461

Electrochemical properties of graphene flakes as an air cathode material for Li-O2 batteries in an ether-based electrolyte.  

PubMed

We employed graphene flakes as an air-cathode material for Li-O2 batteries and investigated their electrochemical properties in the dimethyl ether electrolyte. Graphene flakes were prepared by microwave-assisted reduction of graphene oxide, and their electrochemical properties were compared with those of Ketjen Black and carbon nanotubes. The catalytic effect of the prepared graphene flake-air cathode was demonstrated using cyclic voltammetry and discharge-charge testing performed under a limited discharge capacity. The catalytic effect of graphene flakes was also supported by morphological and spectroscopic analysis of the discharge-charge products formed on the graphene surface. Scanning electron microscopy, X-ray diffraction, and Fourier-transform infrared spectroscopy revealed that Li2O2, Li2O, and Li2CO3 were the main discharge products on all carbon-air cathode surfaces. Raman spectroscopy revealed that LiRCO3 was additionally formed on Ketjen Black and carbon nanotubes during the first discharge; however, its formation was not observed on the graphene flakes. The catalytic effect of the graphene flakes and the absence of LiRCO3 in the discharge product could explain the higher Coulombic efficiency in the discharge-charge tests. PMID:24166701

Kim, Se Young; Lee, Ho-Taek; Kim, Kwang-Bum

2013-12-14

462

Absolute rate parameters for the reaction of ground state atomic oxygen with dimethyl sulfide and episulfide  

NASA Technical Reports Server (NTRS)

It is pointed out that the investigated reaction of oxygen with dimethyl sulfide may play an important role in photochemical smog formation and in the chemical evolution of dense interstellar clouds. Kinetic data were obtained with the aid of the flash photolysis-resonance fluorescence method. The photodecomposition of molecular oxygen provided the oxygen atoms for the experiments. The decay of atomic oxygen was studied on the basis of resonance fluorescence observations. Both reactions investigated were found to be fast processes. A negative temperature dependence of the rate constants for reactions with dimethyl sulfide was observed.

Lee, J. H.; Timmons, R. B.; Stief, L. J.

1976-01-01

463

Polybrominated Diphenyl Ethers Alter Hepatic Phosphoenolpyruvate Carboxykinase Enzyme Kinetics in Male Wistar Rats: Implications for Lipid and Glucose Metabolism  

EPA Science Inventory

Polybrominated diphenyl ethers (PBDE) are a family of lipophilic brominated flame-retardants consisting of 209 possible congeners. Three PBDE commercially-produced mixtures are decabrominated diphenyl ether (e.g. deca-BDE or DE-83R); octabrominated diphenyl ether (e.g. octa-BDE o...

464

Ca-Ca interaction in inverse sandwich Ca-C8H8-Ca.  

PubMed

The inverse sandwich Ca-C8H8-Ca is predicted to be an open-shell singlet state. Since the C8H8 ligand prevents the spin-up and spin-down electrons of different calcium atoms from forming Ca-Ca bonds, the spin-coupling electrons lead to a singlet diradical character. The metal-ligand interaction contributes to the stability of Ca-C8H8-Ca against dissociation and isomerization. For the coordination complex (DME)3Ca-C8H8-Ca(DME)3, the open-shell singlet state is unavailable, while the closed-shell singlet state with direct Ca-Ca bonds is more favorable, because dimethyl ether molecules could push the spin-paired electrons of different calcium atoms to migrate towards the direction of Ca-Ca bonding. For Ca-C4H4-Ca, the ground state is an open-shell singlet state, of which the diradical character is very similar to that of Ca-C8H8-Ca. For (DME)3Ca-C4H4-Ca(DME)3, the lowest energy is the triplet state. PMID:25382394

Liu, Nan-nan; Gao, Si-meng; Ding, Yi-hong

2015-01-01

465

Poly(ether-ether-ketone) orthopedic bearing surface modified by self-initiated surface grafting of poly(2-methacryloyloxyethyl phosphorylcholine).  

PubMed

We investigated the production of free radicals on a poly(ether-ether-ketone) (PEEK) substrate under ultraviolet (UV) irradiation. The amount of the ketyl radicals produced from the benzophenone (BP) units in the PEEK molecular structure initially increased rapidly and then became almost constant. Our observations revealed that the BP units in PEEK acted as photoinitiators, and that it was possible to use them to control the graft polymerization of poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC). This "self-initiated surface graft polymerization" method is very convenient in the absence of external photoinitiator. We also investigated the effects of the monomer concentration and UV irradiation time on the extent of the grafted PMPC layer. Furthermore, as an application to improving the durability of artificial hips, we demonstrated the nanometer-scale photoinduced grafting of PMPC onto PEEK and carbon fiber-reinforced PEEK (CFR-PEEK) orthopedic bearing surfaces and interfaces. A variety of test revealed significant improvements in the water wettability, frictional properties, and wear resistance of the surfaces and interfaces. PMID:23891520

Kyomoto, Masayuki; Moro, Toru; Yamane, Shihori; Hashimoto, Masami; Takatori, Yoshio; Ishihara, Kazuhiko

2013-10-01

466

Polyelectrolyte based on tetra-sulfonated poly(arylene ether)s for direct methanol fuel cell  

NASA Astrophysics Data System (ADS)

A series of tetra-sulfonated poly(arylene ether)s are prepared from a new tetra-sulfonated difluoride monomer and commercial 4,4?-difluorobenzophenone and 4,4?-(hexafluoroisopropylidene)diphenol via polycondensation process. With the content of tetra-sulfonated monomer raising from 15% to 35% in difluoride monomer, sulfonated polymers with ion exchange capacity (IEC) ranging from 0.92 to 1.66 mequiv g-1 are obtained. The high thermal stable polymer owns the glass transition temperature higher than 190 °C and onset decomposition temperature higher than 300 °C. The polymers exhibit good solubility in dimethylacetamide (DMAc) and the tough, flexible and transparent films are obtained by solution casting method. These membranes exhibit suitable proton conductivity, low methanol permeability and excellent dimensional stability. The membrane with IECE = 1.81 mequiv g-1 shows considerable proton conductivity (84 mS cm-1) and swelling ration (only 8.6%) under fully hydrated state at 100 °C. Their excellent performance is attributed to distinct phase separation between hydrophilic and hydrophobic morphology, which is observed by TEM. This work demonstrates that the strategy of combining locally high densities hydrophilic segment with fluorine-containing hydrophobic segment in a polymer chain can balance on proton conduction and dimensional stability efficiently. Furthermore, these membranes own much lower methanol permeability and higher selectivity than Nafion.

Pang, Jinhui; Shen, Kunzhi; Ren, Dianfu; Feng, Sinan; Jiang, Zhenhua

2013-03-01

467

Novel composite proton-exchange membrane based on proton-conductive glass powders and sulfonated poly (ether ether ketone)  

NASA Astrophysics Data System (ADS)

The SiO2-Nafion/sulfonated poly (ether ether ketone) (SPEEK) composite membranes are fabricated by using the simple mechanical ball-milling process to combine SiO2 glass powders with small portion of Nafion, in which SiO2 glass powders are prepared by modified sol-gel progress and Nafion is embedded in situ into a highly porous silica network. The morphology, thermal and mechanical properties, pore structure, proton conductivity and fuel cell performance of the SiO2-Nafion/SPEEK composite membranes are investigated. The poor miscibility of Nafion and sulfonated aromatic polymer is solved by fixing Nafion into SiO2 glass powders. The composite membranes perform well even if the proportion of inorganic component in membranes is as high as 40 wt.%. A maximum of proton conductivity, 0.018 S cm-1, is obtained from the membrane of 4(8Si-2N)/6SPEEK at 80 °C and 90% relative humidity, which is owing to its enhanced hygroscopicity and highly dispersed Nafion clusters. In addition, a single fuel cell equipped with the composite membrane shows a peak power density of 589.2 mW cm-2 at 70 °C.

Di, Zhigang; Xie, Qiang; Li, Haibin; Mao, Dali; Li, Ming; Zhou, Daowu; Li, Lu

2015-01-01

468

Sulfonated poly(ether ether ketone)/mesoporous silica hybrid membrane for high performance vanadium redox flow battery  

NASA Astrophysics Data System (ADS)

Hybrid membranes of sulfonated poly(ether ether ketone) (SPEEK) and mesoporous silica SBA-15 are prepared with various mass ratios for vanadium redox flow battery (VRB) application and investigated in detail. The hybrid membranes are dense and homogeneous with no visible hole as the SEM and EDX images shown. With the increasing of SBA-15 mass ratio, the physicochemical property, VO2+ permeability, mechanical property and thermal stability of hybrid membranes exhibit good trends, which can be attributed to the interaction between SPEEK and SBA-15. The hybrid membrane with 20 wt.% SBA-15 (termed as S/SBA-15 20) shows the VRB single cell performance of CE 96.3% and EE 88.1% at 60 mA cm-2 due to its good balance of proton conductivity and VO2+ permeability, while Nafion 117 membrane shows the cell performance of CE 92.2% and EE 81.0%. Besides, the S/SBA-15 20 membrane shows stable cell performance of highly stable efficiency and slower discharge capacity decline during 120 cycles at 60 mA cm-2. Therefore, the SPEEK/SBA-15 hybrid membranes with optimized mass ratio and excellent VRB performance can be achieved, exhibiting good potential usage in VRB systems.

Li, Zhaohua; Dai, Wenjing; Yu, Lihong; Xi, Jingyu; Qiu, Xinping; Chen, Liquan

2014-07-01

469

A subchronic dermal exposure study of diethylene glycol monomethyl ether and ethylene glycol monomethyl ether in the male guinea pig.  

PubMed

Diethylene glycol monomethyl ether (DEGME) has been selected as a replacement anti-icing additive for ethylene glycol monomethyl ether (EGME) in Navy jet aircraft fuel. This experiment was performed to determine whether DEGME produced similar toxicity to EGME following dermal exposure. Male guinea pigs were dermally exposed to 1.00, 0.20, 0.04, or 0 (control) g/kg/day DEGME for 13 weeks, 5 days/week, 6 hr/day. Another group of animals was similarly exposed to 1.00 g/kg/day EGME. Body weights as well as testicular and splenic weights were reduced as a result of exposure to EGME, DEGME-exposed animals exhibited decreased splenic weight in the high- and medium-dose (1.00 and 0.20 g/kg/day) exposure groups only. Hematologic changes in EGME-exposed animals included mild anemia with increased erythrocytic mean corpuscular volumes and a lymphopenia with increased neutrophils. Similar hematological changes were not observed in any animals exposed to DEGME. Serum creatine kinase activity was increased in animals exposed to EGME, and serum lactate dehydrogenase activity was increased in EGME and 1.00 g/kg/day DEGME-exposed animals. In general, DEGME produced minimal toxicological changes following dermal exposure, whereas the toxicological changes observed following similar exposure to EGME were much more profound. PMID:3699323

Hobson, D W; D'Addario, A P; Bruner, R H; Uddin, D E

1986-02-01

470

Octa­kis(dimethyl sulfoxide-?O)cerium(III) ?6-oxido-dodeca-?2-oxido-hexa­oxidohexa­molybdate(VI) dimethyl sulfoxide tetrasolvate  

PubMed Central

The title complex, [Ce(C2H6OS)8]2[Mo6O19]3·4C2H6OS, was obtained as a byproduct of the reaction of [(C4H9)4N]2[Mo6O19] with Ce(NO3)3·6H2O and phthalic acid in dimethyl­sulfoxide solution. The asymmetric unit consists of a complex [Ce(C2H6OS)8]3+ cation, one and a half of the Lindqvist-type [Mo6O19]2? polyanions and two dimethyl­sulfoxide solvent mol­ecules; the half polyanion lies on an inversion center. The Ce3+ ion is coordinated by eight dimethyl­sulfoxide ligands through the O atoms in the form of a distorted square antiprism. The Ce—O bond lengths range from 2.429?(6) to 2.550?(5)?Å. The cohesion of the structure is ensured by S?O [3.115?(6), 3.242?(10) and 3.12?(3)?Å], O?O [3.037?(10)?Å] and C—H?O inter­actions between cations and anions. The S and C atoms of a dmso ligand are disordered over three sites in a 0.45:0.30:0.25 ratio. The dimethyl­sulfoxide solvent mol­ecules are highly disordered and could not be modelled successfully; their contribution was therefore removed from the refinement using the SQUEEZE routine in PLATON [Spek (2009 ?). Acta Cryst. D65, 148–155]. Potential solvent-accessible voids of 500.0?Å3 occur in the crystal structure. PMID:22807767

Ben Khélifa, Arbia; Giorgi, Michel; Belkhiria, Mohamed Salah

2012-01-01

471

Bis(?-N,N-dimethyl­dithio­carbamato-?3 S,S?:S)bis­[(N,N-dimethyl­dithio­carbamato-?2 S,S?)copper(II)  

PubMed Central

In the centrosymmetric dimeric title compound, [Cu2(C3H6NS2)4], the CuII atom is five-coordinate in a square-pyramidal environment. The basal coordination positions are occupied by four S atoms from two dimethyl­dithio­carbamate ligands and the apical coordination position is occupied by an S atom also bonded to the other Cu atom. PMID:21582093

Fan, Le-Qing; Wu, Ji-Huai

2009-01-01

472

40 CFR 721.10473 - 1-Propanaminium, 3-amino-N-(2-carboxyethyl)-N,N-dimethyl-, N-coco acyl derivs., inner salts.  

Code of Federal Regulations, 2013 CFR

...N-dimethyl-, N-coco acyl derivs., inner salts. 721.10473 Section 721.10473...N-dimethyl-, N-coco acyl derivs., inner salts. (a) Chemical substance and significant...N-dimethyl-, N-coco acyl derivs., inner salts (PMN P-03-865; CAS No....

2013-07-01

473

40 CFR 721.10055 - 1-Propanaminium, 3-amino-N-(carboxymethyl)-N,N-dimethyl-, N-soya acyl derivs., inner salts.  

Code of Federal Regulations, 2013 CFR

...N-dimethyl-, N-soya acyl derivs., inner salts. 721.10055 Section 721.10055...dimethyl-, N -soya acyl derivs., inner salts. (a) Chemical substance and significant...dimethyl-, N -soya acyl derivs., inner salts (PMN P-03-46; CAS No....

2013-07-01

474

40 CFR 721.10055 - 1-Propanaminium, 3-amino-N-(carboxymethyl)-N,N-dimethyl-, N-soya acyl derivs., inner salts.  

Code of Federal Regulations, 2010 CFR

...N-dimethyl-, N-soya acyl derivs., inner salts. 721.10055 Section 721.10055...dimethyl-, N -soya acyl derivs., inner salts. (a) Chemical substance and significant...dimethyl-, N -soya acyl derivs., inner salts (PMN P-03-46; CAS No....

2010-07-01

475

75 FR 79368 - Tetrahydro-3, 5-dimethyl-2H-1, 3, 4-thiadiazine-2-thione; Amendment To Terminate and or Delete...  

Federal Register 2010, 2011, 2012, 2013, 2014

...Tetrahydro-3, 5-dimethyl-2H-1, 3, 4-thiadiazine-2-thione; Amendment To...tetrahydro-3, 5-dimethyl-2H-1, 3, 4-thiadiazine-2-thione (Dazomet) product...tetrahydro-3, 5-dimethyl-2H-1, 3, 4-thiadiazine- 2-thione products...

2010-12-20

476

Iptycene-derived crown ether hosts for molecular recognition and self-assembly.  

PubMed

CONSPECTUS: Synthetic macrocyclic hosts have played key roles in the development of host-guest chemistry. Crown ethers are a class of macrocyclic molecules with unique flexible structures. They have served as the first generation of synthetic hosts, and researchers have extensively studied them in molecular recognition. However, the flexible structures of simple crown ethers and their relatively limited modes of complexation with guests have limited the further applications of these molecules. In recent years, researchers have moved toward fabricating interlocking molecules, supramolecular polymers, and other assemblies with specific structures and properties. Therefore, researchers have developed more complex crown ether-based macrocyclic hosts with multicavity structures and multicomplexation modes that provide more diverse and sophisticated host-guest systems. In this Account, we summarize our research on the synthesis and characterization of iptycene-derived crown ether hosts, their use as host molecules, and their applications in self-assembled complexes. Iptycenes including triptycenes and pentiptycenes are a class of aromatic compounds with unique rigid three-dimensional structures. As a result, they are promising building blocks for the synthesis of novel macrocyclic hosts and the construction of novel self-assembled complexes with specific structures and properties. During the last several years, we have designed and synthesized a new class of iptycene-derived crown ether hosts including macrotricyclic polyethers, molecular tweezer-like hosts, and tritopic tris(crown ether) hosts, which are all composed of rigid iptycene building blocks linked by flexible crown ether chains. We have examined the complexation behavior of these hosts with different types of organic guest molecules. Unlike with conventional crown ethers, the combination of iptycene moieties and crown ether chains provides the iptycene-derived crown ether hosts with complexation properties that differ based on the structure of the guests. The rigid iptycene moieties within these synthetic host molecules both maintain their inherent three-dimensional cavities and generate multicavity structures. The flexible crown ether chains allow the iptycene-derived hosts to adjust their conformations as they encapsulate guest molecules. Moreover, the expanded complexation properties also allow the host-guest systems based on the iptycene-derived crown ethers to respond to multiple external stimuli, resulting in a variety of supramolecular assemblies. Finally, we also describe the construction of mechanically interlocked self-assemblies, molecular switches/molecular machines, and supramolecular polymers using these new host molecules. We expect that the unique structural features and diverse complexation properties of these iptycene-derived crown ether hosts will lead to increasing interest in this field and in supramolecular chemistry overall. PMID:24877894

Han, Ying; Meng, Zheng; Ma, Ying-Xian; Chen, Chuan-Feng

2014-07-15

477

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

PubMed

Carbon nanotubes (CNTs) are a kind of new carbon-based nano-materials which have drawn great attention in many application fields. The potential single-walled carbon nanotubes (SWCNTs) as solid-phase microextraction (SPME) adsorbents for the preconcentration of environmental pollutants have been investigated in recent years. The goal of this work was to investigate the feasibility of SWCNTs used as adsorbents for solid-phase microextraction of methyl tert-butyl ether (MTBE), ethyl tert-butyl ether (ETBE) and tert-amyl methyl ether (TAME) in human urine. SWCNTs were attached onto a stainless steel wire through organic binder. Potential factors affecting the extraction efficiency were optimized, including extraction time, extraction temperature, desorption time, desorption temperature, and salinity. The developed method showed good performance according to the ICH performance criteria for bioanalytical methods. The calibration curves of the ethers were linear (r(2)>or=0.992) in the range from 10 to 5000 ng L(-1). The limits of detection at a signal-to-noise (S/N) ratio of 3 were 10 ng L(-1) for all the analytes. In addition, compared with the commercial carboxen/polydimethylsiloxane (CAR/PDMS) fiber, the SWCNT fiber showed better thermal stability (over 350 degrees C) and longer life span (over 150 times). The developed method was applied successfully to determine trace level of the ethers in urine of 10 healthy male volunteers. PMID:19395320

Rastkari, Noushin; Ahmadkhaniha, Reza; Yunesian, Masud

2009-05-15

478

Alcohol/ether separation by pervaporation. High performance membrane design  

SciTech Connect

Several routes were investigated to design high performance membranes for the separation of tert-butyl ethers (octane enhancers) from alcohols by pervaporation. These routes aim at incorporating Lewis base groups into good film-forming polymers with different structures. The Lewis base groups showed a high affinity to alcohols in screening tests, thus imparting high pervaporation selectivity to the polymer materials. They led to several membranes able to extract pure ethanol out of the azeotropic mixture, but with very low permeation rates. Further modifications of the polymer structure allowed the authors to synthesize materials with greatly enhanced transfer rates and with acceptable selectivity for industrial applications. Structure-property relationships were derived from sorption and pervaporation data for a qualitative prediction of the effect of polymer structure on the flux and selectivity. For these solvent-polymer systems the diffusion phenomenon appears to further improve the pervaporation selectivity for alcohol compared with that given by the sorption process at the membrane face.

Roizard, D.; Jonquieres, A.; Leger, C. [Ecole Nationale Superieure des Industries Chimiques, Nancy (France). Lab. de Chimie-Physique Macromoleculaire] [and others] [Ecole Nationale Superieure des Industries Chimiques, Nancy (France). Lab. de Chimie-Physique Macromoleculaire; and others

1999-02-01

479

The influence of water mixtures on the dermal absorption of glycol ethers  

SciTech Connect

Glycol ethers are solvents widely used alone and as mixtures in industrial and household products. Some glycol ethers have been shown to have a range of toxic effects in humans following absorption and metabolism to their aldehyde and acid metabolites. This study assessed the influence of water mixtures on the dermal absorption of butoxyethanol and ethoxyethanol in vitro through human skin. Butoxyethanol penetrated