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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

STATE OF THE ART OF DIMETHYL ETHER, DME SYNTHESIS AND THE POSSIBILITY OF ITS PRODUCTION FROM SUGARCANE BIOMASS IN BRAZIL  

Microsoft Academic Search

Brazil is a tropical and equatorial country with a great vocation for biomass. Sugarcane has assumed an important role among other biomass in Brazil in terms of its potential to liberate large amounts of residual biomass from very large agroindustries in a point of use. The possibility of synthesis of Di-Methyl Ether, DME, a new clean and economical energy carrier,

Felipe Moreton Chohfi; José Dilcio Rocha; Juan Miguel Mesa Pérez

3

An investigation of the effects of spray angle and injection strategy on dimethyl ether (DME) combustion and exhaust emission characteristics in a common-rail diesel engine  

Microsoft Academic Search

An experimental investigation was performed on the effects of spray angle and injection strategies (single and multiple) on the combustion characteristics, concentrations of exhaust emissions, and the particle size distribution in a direct-injection (DI) compression ignition engine fueled with dimethyl ether (DME) fuel. In this study, two types of narrow spray angle injectors (?spray=70° and 60°) were examined and its

Seung Hyun Yoon; June Pyo Cha; Chang Sik Lee

2010-01-01

4

DIMETHYL ETHER PRODUCTION VIA METHANOL OVER ZEOLITES  

Microsoft Academic Search

Catalytic dehydration of methanol is commercially important for the production of dimethyl ether (DME). DME, a natural gas derived product, is a useful building block for making important chemicals, including dimethyl sulfate and high valued oxygenated compounds. DME is also used as an aerosol propellant in products such as hair spray and shaving cream because of its environmentally benign properties

Flávia Gutman Barbosa; Marta Antunes Pereira Langone; Mônica Antunes; Pereira da Silva

5

Thrust measurement of dimethyl ether arcjet thruster  

Microsoft Academic Search

The present paper describes thrust measurement results for an arcjet thruster using Dimethyl ether (DME) as the propellant. DME is an ether compound and can be stored as a liquid due to its relatively low freezing point and preferable vapor pressure. The thruster successfully produced high-voltage mode at DME mass flow rates above 30mg\\/s, whereas it yielded low-voltage mode below

Akira Kakami; Shinji Beppu; Muneyuki Maiguma; Takeshi Tachibana

2011-01-01

6

Measurement of Vapor-Liquid Equilibrium for the DME + Diisopropyl Ether Binary System and Correlation for the DME + CO2 + Diisopropyl Ether Ternary System  

NASA Astrophysics Data System (ADS)

Vapor-liquid equilibrium (VLE) data have been measured with a static-type VLE apparatus for the dimethyl ether (DME)-diisopropyl ether (DIPE) binary system at five temperatures within the range from 293.04 K to 352.70 K. An isothermal correlation for the experimental data has been carried out based on the Peng-Robinson equation of state. The regressed binary interaction parameters were used to estimate VLE for the DME-CO2-DIPE ternary system at 298.15 K. From the study, it is demonstrated that DIPE is an excellent absorbent for separation in the DME synthesis process from syngas.

Wu, Xianghong; Du, Xiaojie; Zheng, Danxing

2010-02-01

7

Effective utilization of remote coal through dimethyl ether synthesis  

Microsoft Academic Search

Dimethyl ether (DME) is a clean and sustainable alternative fuel that can be produced from natural gas, coal or other organic resources through syngas. The properties of DME are suitable for the production of power generation fuel, transportation fuel, home fuel and chemicals. Production of DME fuel from unutilized natural gas or coal resources in remote areas will contribute in

Y Adachi; M Komoto; I Watanabe; Y Ohno; K Fujimoto

2000-01-01

8

High-temperature pyrolysis of dimethyl ether in shock waves  

Microsoft Academic Search

The high-temperature pyrolysis of dimethyl ether (DME) was studied behind reflected shock waves using single-pulse (reaction time between 1.3 and 2.9 ms), time-resolved IR absorption (3.39 ?m), IR emission (4.24 ?m), and UV absorption (216 nm) methods. The studies were done using DME-Ar, DME-H2-Ar, DME-CO-Ar, and DME-CH2O-Ar mixtures in the temperature range 900–1900 K at pressures in the range 0.83–2.9

Yoshiaki Hidaka; Kazutaka Sato; Masatsugu Yamane

2000-01-01

9

Design and Experiment of Thrusters Using Dimethyl Ether  

NASA Astrophysics Data System (ADS)

We proposed new thrusters using Dimethyl ether (DME) as propellant: DME arcjet thruster and liquid propellant thruster using plasma assisted combustion. DME has a freezing point of -143ºC, a boiling point of -54ºC, and liquefies at 6atm under room temperature. Thus, DME can be stored as a liquid without cryogenic device. DME has little toxicity and is chemically stable. A DME arcjet thruster prototype operated in a discharge power range from 1000W to 1600W and a plenum chamber pressure reached 160kPa. We also designed a liquid propellant thruster prototype using DME plasma assisted combustion. The plasma successfully sustained the combustion of DME and Hydroxyl Ammonium Nitrate oxidizer. At a discharge power of approximately 3kW, the measurement of the thrust chamber pressure yielded a C* efficiency of 0.39 and an estimated specific impulse of 114s.

Kakami, Akira; Yokote, Jun; Ebara, Isao; Shuzenji, Kiyotaka; Tachibana, Takeshi

10

Characteristics of biosolids in dimethyl ether dewatering method.  

PubMed

In this study, a method for removing water from biosolids that uses dimethyl ether (DME) as an extractant was considered. This study evaluates the applicability of the DME dewatering method to biosolid cakes by using a DME flow-type experimental apparatus. It was found that a high dewatering ratio is clearly achieved by increasing the liquefied DME/biosolid ratio and lowering the liquefied DME linear velocity. As the liquefied DME/biosolid ratio was increased, the carbon content in dewatered biosolid showed a slight decrease and the TOC concentration in separated liquid increased significantly. Finally, the input energy Es to remove 1 kg of water from the biosolid cake, using both the DME dewatering method and the conventional drying method was estimated. The calculation shows that Es for the DME dewatering process is approximately a third of Es for the conventional thermal drying process. PMID:22515061

Oshita, Kazuyuki; Takaoka, Masaki; Nakajima, Yusuke; Morisawa, Shinsuke; Kanda, Hideki; Makino, Hisao; Takeda, Nobuo

2012-02-01

11

Synthesis of dimethyl ether from methane mediated by HBr  

Microsoft Academic Search

Dimethyl ether (DME) was synthesized from methane through a two-step process, in which CH3Br was prepared from the oxidative bromination reaction of methane in the presence of HBr and oxygen over a Rh-SiO2 catalyst and then, in the second step, CH3Br was hydrolyzed to DME over a silica supported metal chloride catalyst. 12 mol%ZnCl2\\/SiO2 catalyst was found to be the

Qin You; Zhen Liu; Wensheng Li; Xiaoping Zhou

2009-01-01

12

Kinetics and modelling of dimethyl ether synthesis from synthesis gas  

Microsoft Academic Search

The kinetics of the dual catalytic methanol and dimethyl ether (DME) synthesis process over a commercial CuO\\/ZnO\\/Al2O3 (methanol forming) and a ?-alumina (dehydration) catalyst have been investigated at 250°C and 5 MPa using a gradientless, internal-recycle-type reactor. A kinetic model for the combined methanol+DME synthesis based on a methanol synthesis model proposed by Vanden Bussche and Froment (1996) J. Catal.,

K. L. Ng; D. Chadwick; B. A. Toseland

1999-01-01

13

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

14

CH3O(A-X) fluorescence from photodissociation of dimethyl ether  

NASA Technical Reports Server (NTRS)

The paper reports the quantitative photoabsorption and fluorescence cross sections of dimethyl ether (DME) measured with synchrotron radiation. Determinations were also made of the absolute fluorescence cross sections, the fluorescence quantum yield, and the radiative lifetime.

Suto, Masako; Ye, Chao; Lee, L. C.

1988-01-01

15

Monte Carlo predictions of phase equilibria and structure for dimethyl ether + sulfur dioxide and dimethyl ether + carbon dioxide  

NASA Astrophysics Data System (ADS)

A new force field for dimethyl ether (DME) based on the Lennard-Jones (LJ) 12-6 plus point charge functional form is presented in this work. This force field reproduces experimental saturated liquid and vapor densities, vapor pressures, heats of vaporization, and critical properties to within the statistical uncertainty of the combined experimental and simulation measurements for temperatures between the normal boiling and critical point. Critical parameters and normal boiling point are predicted to within 0.1% of experiment. This force field is used in grand canonical histogram reweighting Monte Carlo simulations to predict the pressure composition diagrams for the binary mixtures DME + SO2 at 363.15 K and DME + CO2 at 335.15 and 308.15 K. For the DME + SO2 mixture, simulation is able to qualitatively reproduce the minimum pressure azeotropy observed experimentally for this mixture, but quantitative errors exist, suggesting that multibody effects may be important in this system. For the DME + CO2 mixture, simulation is able to predict the pressure-composition behavior within 1% of experimental data. Simulations in the isobaric-isothermal ensemble are used to determine the microstructure of DME + SO2 and DME + CO2 mixtures. The DME + SO2 shows weak pairing between DME and SO2 molecules, while no specific pairing or aggregation is observed for mixtures of DME + CO2.

Kamath, Ganesh; Ketko, Marybeth; Baker, Gary A.; Potoff, Jeffrey J.

2012-01-01

16

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

17

Biomass to dimethyl ether by gasification\\/synthesis technology—an alternative biofuel production route  

Microsoft Academic Search

Technical and economic analysis was done for the biomass to dimethyl ether (DME) technology to promote the gasification\\/synthesis\\u000a route for biofuel production and its application as a fossil fuel substitute. The technology of biomass gasification\\/synthesis\\u000a has obvious advantages, including production flexibility, environmental friendliness, economic feasibility, and application\\u000a versatility. Biomass gasification\\/synthesis technology integrates bio-DME synthesis, fertilizer production, electricity generation,\\u000a and waste

Tiejun Wang; Yuping Li; Longlong Ma; Chuangzhi Wu

2011-01-01

18

Laser-induced plasma in methane and dimethyl ether for flame ignition and combustion diagnostics  

Microsoft Academic Search

In this paper we report the investigation of the laser-induced breakdown and ignition behaviour of methane\\/air and dimethyl ether (DME)\\/air mixtures. Moreover, the optical emission from the induced plasma is utilized for determining the mixture composition quantitatively by means of laser-induced breakdown spectroscopy (LIBS). To the best of the authors' knowledge, LIBS and laser ignition of DME have not been

J. Kiefer; J. W. Tröger; Z. S. Li; M. Aldén

2011-01-01

19

Laser-induced plasma in methane and dimethyl ether for flame ignition and combustion diagnostics  

Microsoft Academic Search

In this paper we report the investigation of the laser-induced breakdown and ignition behaviour of methane\\/air and dimethyl\\u000a ether (DME)\\/air mixtures. Moreover, the optical emission from the induced plasma is utilized for determining the mixture composition\\u000a quantitatively by means of laser-induced breakdown spectroscopy (LIBS). To the best of the authors’ knowledge, LIBS and laser\\u000a ignition of DME have not been

J. Kiefer; J. W. Tröger; Z. S. Li; M. Aldén

2011-01-01

20

Process simulation of single-step dimethyl ether production via biomass gasification  

Microsoft Academic Search

In this study, we simulated the single-step process of dimethyl ether (DME) synthesis via biomass gasification using ASPEN Plus™. The whole process comprised four parts: gasification, water gas shift reaction, gas purification, and single-step DME synthesis. We analyzed the influence of the oxygen\\/biomass and steam\\/biomass ratios on biomass gasification and synthesis performance. The syngas H2\\/CO ratio after water gas shift

Fudong Ju; Hanping Chen; Xuejun Ding; Haiping Yang; Xianhua Wang; Shihong Zhang; Zhenghua Dai

2009-01-01

21

On blue shifts of C--H stretching modes of dimethyl ether in hydrogen- and halogen-bonded complexes  

NASA Astrophysics Data System (ADS)

A systematic investigation of a representative series of intermolecular complexes formed between dimethyl ether (DME) and various interacting partners such as H 2O, hydrogen halides, dihalogens, halomethanes, DME, and the ions Li + and H + was performed at the MP2/6-311++G(2d,2p) computational level. Although, except (DME) 2, DME-HCF 3, DME-HCClF 2, and DME-HCCl 2F, the C-H bonds of DME are not involved in the hydrogen bonding of these complexes, their C-H stretching frequencies are all blue-shifted. It is shown that the mechanism of these blue shifts originates from the existence of a negative intramolecular coupling between the C-O and C-H bonds inherent to the DME molecule.

Karpfen, Alfred; Kryachko, Eugene S.

2006-11-01

22

Atmospheric fate of dimethyl and fluorinated ethers  

Microsoft Academic Search

The purpose of the present study was to evaluate the environmental significance of dimethyl ether and the fluorinated ethers E143a (CH3OCF 3), E134 (CHF2OCHF2), E125 (CHF2OCF 3), and E216 (CF3OCF=CF2). Dimethyl ether is a proposed diesel fuel substitute. Concerns about mobile source emissions and their impact on urban tropospheric ozone formation have spurred research into alternative fuels. The fluorinated ethers

David Alan Good

1999-01-01

23

Growth characteristics of polycyclic aromatic hydrocarbons in dimethyl ether diffusion flame  

Microsoft Academic Search

The growth characteristics of polycyclic aromatic hydrocarbons (PAHs) in laminar dimethyl ether (DME) diffusion flame were investigated experimentally, and we assumed that the growth of PAHs within the flame was predominantly due to methyl addition\\/cyclization (MAC) mechanism. Methane and propane laminar diffusion flames were also investigated for comparison, and their PAHs growth characteristics had been explained by reactions concerning acetylene

Kazuhiro Hayashida; Toshio Mogi; Kenji Amagai; Masataka Arai

2011-01-01

24

Optimal conditions for hydrogen production from coupling of dimethyl ether and benzene synthesis  

Microsoft Academic Search

Coupling energy intensive endothermic reaction systems with suitable exothermic reactions followed by hydrogen permeation through the Pd\\/Ag membrane improves the thermal efficiency of processes, achieving the autothermality within the reactor, reduces the size of reactors, produces the pure hydrogen, and achieving a multiple reactants multiple products configuration. This paper focuses on optimization of hydrogen, dimethyl ether (DME) and benzene production

M. Farsi; M. H. Khademi; A. Jahanmiri; M. R. Rahimpour

2011-01-01

25

Thrust Evaluation of an Arcjet Thruster Using Dimethyl Ether as a Propellant  

NASA Astrophysics Data System (ADS)

This paper describes the performance of an arcjet thruster using dimethyl ether (DME) as a propellant. DME, an ether compound, has adequate characteristics for space propulsion systems; DME is storable in a liquid state without a high pressure or cryogenic device and requires no sophisticated temperature management. DME is gasified and liquefied simply by adjusting temperature, whereas hydrazine, a conventional propellant, requires an iridium-based particulate catalyst for its gasification. In this study, thrust of the designed kW-class DME arcjet thruster is measured with a torsional thrust stand. Thrust measurements show that thrust is increased with propellant mass flow rate, and that thrust using DME propellant is higher than when using nitrogen. The prototype DME arcjet thruster yields a specific impulse of 330 s, a thruster efficiency of 0.14, and a thrust of 0.19 N at 60-mg/s DME mass flow rate at 25-A discharge current. The corresponding discharge power and specific power are 2.3 kW and 39 MJ/kg.

Kakami, Akira; Beppu, Shinji; Maiguma, Muneyuki; Tachibana, Takeshi

26

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

27

Vapour–liquid equilibrium data for the 1,1,1,2 tetrafluoroethane (R134a) + dimethyl ether (DME) system at temperatures from 293.18 to 358.15 K and pressures up to about 3 MPa  

Microsoft Academic Search

Isothermal vapour–liquid equilibrium data have been measured for the binary system R134a+DME at five temperatures between 293.18 and 358.15K, and pressures between 0.4899 and 2.9442MPa. The peculiarity of this system is the existence of an azeotrope with a minimum pressure, which disappears at 358.15K. The experimental method used in this work is of the static-analytic type, taking advantage of two

Alain Valtz; Leila Gicquel; Christophe Coquelet; Dominique Richon

2005-01-01

28

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  

Microsoft Academic Search

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 (γ-alumina) was demonstrated. It provided the productivity and selectivity expected from the LPDME process.

Xiang-Dong Peng

2002-01-01

29

Modeling and simulation of tube-shell reactor for dimethyl-ether synthesis from coal-based synthesis gas  

Microsoft Academic Search

Mathematical simulation was performed on tube-shell reactor for dimethyl ether (DME) synthesis from coal-based syngas. The\\u000a model was established based on kinetics of dimethyl-ether synthesis from syngas over a bifunctional catalyst, which is mixed\\u000a by methanol synthesis catalyst and dehydration catalyst as 1:1 mass ratio. Methanol synthesis from CO and CO2 and methanol dehydration were selected as three-independent reactions, CO,

Da-sheng Chen; Hai-tao Zhang; Wei-yong Ying; Ding-ye Fang

2011-01-01

30

Experimental and Modeling Study of Premixed Atmospheric-Pressure Dimethyl Ether?Air Flames  

Microsoft Academic Search

Chemical species profiles have been measured at atmospheric pressure for two dimethyl ether (DME)-air flat flames having fuel-air equivalence ratios of 0.67 and 1.49. The samples, obtained with an uncooled quartz probe, were analyzed by either gas chromatography or Fourier transform infrared (FTIR) spectroscopy for CH4, C2H2, C2H4, C2H6, C3H8, DME, CO, CO2, O2, CH2O, and formic acid. A pneumatic

E. W. Kaiser; T. J. Wallington; M. D. Hurley; J. Platz; H. J. Curran; W. J. Pitz; C. K. Westbrook

2000-01-01

31

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

32

Synthesis of AlOOH slurry catalyst and catalytic activity for methanol dehydration to dimethyl ether  

Microsoft Academic Search

AlOOH slurry catalysts were prepared by complete liquid-phase technology from aluminum iso-propoxide (AIP). Dehydration of methanol to dimethyl ether (DME) over these catalysts was investigated in slurry reactor. The catalysts were characterized by X-ray diffraction(XRD), nitrogen adsorption, temperature-programmed desorption of ammonia (NH3-TPD). The results showed that the slurry catalysts had high specific surface area and pore volume, and the specific

Lei Liu; Wei Huang; Zhi-hua Gao; Li-hua Yin

33

Molecular dynamics study of Acid-catalyzed hydrolysis of dimethyl ether in aqueous solution.  

PubMed

The acid-catalyzed hydrolysis of dimethyl ether (DME) to methanol was examined using ab initio density functional metadynamics simulations. Diffusion of the acid proton from the aqueous medium, leading to the formation of a protonated DME, is 12.3 kcal mol(-1) activated and 9.3 kcal mol(-1) endothermic, indicating a greater affinity of the acid proton to water than to the ether group. Subsequent scission of the protonated ether bond is found to be 30.7 kcal mol(-1) activated, leading to the formation of a solvated methyl-carbocation, which is thermodynamically unstable. The methyl-carbocation reacts readily to form methanol and regenerate the acid proton. PMID:21651303

Liang, Xiao; Montoya, Alejandro; Haynes, Brian S

2011-06-30

34

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

35

Durability of WO 3\\/ZrO 2–CuO\\/CeO 2 catalysts for steam reforming of dimethyl ether  

Microsoft Academic Search

Development of catalysts for steam reforming of dimethyl ether (DME) producing hydrogen was carried out with the aim of improving catalyst durability. The catalyst consisted of a mixture of solid acid catalysts for hydration of DME to methanol and 40wt.% CuO\\/CeO2 catalyst for steam reforming of methanol. Among various acid catalysts examined, 10wt.% WO3\\/ZrO2 had the highest performance. WO3\\/ZrO2 showed

Toshiya Nishiguchi; Kengo Oka; Tomoaki Matsumoto; Hiroyoshi Kanai; Kazunori Utani; Seiichiro Imamura

2006-01-01

36

Separation of Dimethyl Ether from Syn-Gas Components by Poly(dimethylsiloxane) and Poly(4-methyl-1-pentene) Membranes  

SciTech Connect

Permeability and selectivity in gas transport through poly(4-methyl-1-pentene) (TPX) and poly(dimethylsiloxane) (PDMS) using variable temperature mixed gas experiments is reported. Selected gases include H2, CO, CH4, CO2, and dimethyl ether (DME). The DME data is the first to be reported through these membranes. In this paper, the chosen polymers reflect both rubbery and crystalline materials. Rubbery polymers tend to be weakly size sieving, which, in this work, has resulted in larger permeabilities, lower separation factors, and lower activation energies of permeation (Ep). Conversely, the crystalline TPX membranes showed much greater sensitivity to penetrant size; although the gas condensability also played a role in transport.

Christopher J. Orme; Frederick F. Stewart

2011-05-01

37

Modification of Cu-based methanol synthesis catalyst for dimethyl ether synthesis from syngas in slurry phase  

Microsoft Academic Search

The Cu-based methanol synthesis catalyst was modified with Mn to improve its activity and stability for dimethyl ether (DME) synthesis from syngas in slurry phase. Mn was added by impregnating co-precipitated CuZnAl catalyst with aqueous solution of manganese nitrate (Mn\\/CuZnAl) or co-precipitation of the nitrates of Cu, Zn, Al and Mn (CuZnAlMn). The catalyst characterizations by H2-TPD and XRD showed

Yisheng Tan; Hongjuan Xie; Haitao Cui; Yizhuo Han; Bing Zhong

2005-01-01

38

Catalytic dehydration of methanol to dimethyl ether over micro–mesoporous ZSM-5\\/MCM-41 composite molecular sieves  

Microsoft Academic Search

A series of micro–mesoporous ZSM-5\\/MCM-41 composite molecular sieves were prepared by combining a microporous zeolite silica source with nano self-assembly methods, and characterized by SEM, TEM, XRD, N2 adsorption and desorption, TPD of ammonia, and their catalytic performance for the dehydration of methanol to dimethyl ether (DME) in a fixed bed microreactor at atmospheric pressure. Among these catalysts, the ZSM-5\\/MCM-41

Qiang Tang; Hang Xu; Yanyan Zheng; Jinfu Wang; Hansheng Li; Jun Zhang

39

The direct synthesis of dimethyl ether from syngas over hybrid catalysts with sulfate-modified ?-alumina as methanol dehydration components  

Microsoft Academic Search

A series of ?-Al2O3 samples modified with various contents of sulfate (0–15wt.%) and calcined at different temperatures (350–750°C) were prepared by an impregnation method and physically admixed with CuO–ZnO–Al2O3 methanol synthesis catalyst to form hybrid catalysts. The direct synthesis of dimethyl ether (DME) from syngas was carried out over the prepared hybrid catalysts under pressurized fixed-bed continuous flow conditions. The

Dongsen Mao; Weimin Yang; Jianchao Xia; Bin Zhang; Guanzhong Lu

2006-01-01

40

Direct synthesis of dimethyl ether from carbon-monoxide-rich synthesis gas: Influence of dehydration catalysts and operating conditions  

Microsoft Academic Search

Various dehydration catalysts were studied in the synthesis of dimethyl ether (DME) directly from carbon-monoxide-rich synthesis gas under a series of different reaction conditions. The investigated catalyst systems consisted of combinations of a methanol catalyst (CuO\\/ZnO system) with catalysts for methanol dehydration based on ?-Al2O3 or zeolites and ?-Al2O3 was identified as the most favorable dehydration catalyst. Various reaction parameters

Miriam Stiefel; Ruaa Ahmad; Ulrich Arnold; Manfred Döring

2011-01-01

41

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

42

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.

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

2014-01-01

43

Synthesis of dimethyl ether and alternative fuels in the liquid phase from coal-derived synthesis gas. Task 2.2: Definition of preferred catalyst system; Task 2.3: Process variable scans on the preferred catalyst system; Task 2.4: Life-test on the preferred catalyst system.  

National Technical Information Service (NTIS)

As part of the DOE-sponsored contract for the Synthesis of Dimethyl Ether (DME) and Alternative Fuels in the Liquid Phase from Coal- Derived Syngas, the single-step, slurry phase DME synthesis process was developed. The development involved screening of c...

B. L. Bhatt

1992-01-01

44

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

45

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

46

Thermodynamic equilibrium calculations of hydrogen production from the combined processes of dimethyl ether steam reforming and partial oxidation  

NASA Astrophysics Data System (ADS)

Thermodynamic analyses of producing a hydrogen-rich fuel-cell feed from the combined processes of dimethyl ether (DME) partial oxidation and steam reforming were investigated as a function of oxygen-to-carbon ratio (0.00-2.80), steam-to-carbon ratio (0.00-4.00), temperature (100 °C-600 °C), pressure (1-5 atm) and product species. Thermodynamically, dimethyl ether processed with air and steam generates hydrogen-rich fuel-cell feeds; however, the hydrogen concentration is less than that for pure DME steam reforming. Results of the thermodynamic processing of dimethyl ether indicate the complete conversion of dimethyl ether to hydrogen, carbon monoxide and carbon dioxide for temperatures greater than 200 °C, oxygen-to-carbon ratios greater than 0.00 and steam-to-carbon ratios greater than 1.25 at atmospheric pressure ( P = 1 atm). Increasing the operating pressure has negligible effects on the hydrogen content. Thermodynamically, dimethyl ether can produce concentrations of hydrogen and carbon monoxide of 52% and 2.2%, respectively, at a temperature of 300 °C, and oxygen-to-carbon ratio of 0.40, a pressure of 1 atm and a steam-to-carbon ratio of 1.50. The order of thermodynamically stable products (excluding H 2, CO, CO 2, DME, NH 3 and H 2O) in decreasing mole fraction is methane, ethane, isopropyl alcohol, acetone, n-propanol, ethylene, ethanol and methyl-ethyl ether; trace amounts of formaldehyde, formic acid and methanol are observed. Ammonia and hydrogen cyanide are also thermodynamically favored products. Ammonia is favored at low temperatures in the range of oxygen-to-carbon ratios of 0.40-2.50 regardless of the steam-to-carbon ratio employed. The maximum ammonia content (i.e., 40%) occurs at an oxygen-to-carbon ratio of 0.40, a steam-to-carbon ratio of 1.00 and a temperature of 100 °C. Hydrogen cyanide is favored at high temperatures and low oxygen-to-carbon ratios with a maximum of 3.18% occurring at an oxygen-to-carbon ratio of 0.40 and a steam-to-carbon ratio of 0.00 in the temperature range of 400 °C-500 °C. Increasing the system pressure shifts the equilibrium toward ammonia and hydrogen cyanide.

Semelsberger, Troy A.; Borup, Rodney L.

47

Kinetic Understanding of the Syngas-to-DME Reaction System and It's Implications to Process and Economics.  

National Technical Information Service (NTIS)

In a single-step synthesis gas-to-dimethyl ether process, synthesis gas (or syngas, a mixture of H(sub 2) and CO) is converted into dimethyl ether (DME) in a single reactor. The three reactions involved in this process, methanol synthesis, methanol dehydr...

X. D. Peng

2002-01-01

48

Modification of acid properties and catalytic properties of AlPO 4 by hydrothermal pretreatment for methanol dehydration to dimethyl ether  

Microsoft Academic Search

An amorphous AlPO4 catalyst prepared by precipitation method was subjected to pretreatment with 10mol% water vapor at 100–300°C for 15min prior to activity tests in the dehydration of methanol to dimethyl ether (DME). The catalysts pretreated at 200–300°C exhibited higher methanol conversion than the non-treated catalyst while the one treated at a lower temperature of 100°C showed lower activity. As

Krit Lertjiamratn; Piyasan Praserthdam; Masahiko Arai; Joongjai Panpranot

2010-01-01

49

Highly effective hybrid catalyst for the direct synthesis of dimethyl ether from syngas with magnesium oxide-modified HZSM-5 as a dehydration component  

Microsoft Academic Search

A series of HZSM-5 zeolites modified with various contents of magnesium oxide (0–10 wt%) were prepared with an incipient impregnation technique and characterized by X-ray diffraction, N2 adsorption, temperature-programmed desorption of NH3 and CO2, 27Al MAS NMR, and FT-IR. The modified HZSM-5 zeolites were mixed physically with methanol synthesis components (CuO–ZnO–Al2O3) to perform the direct synthesis of dimethyl ether (DME)

Dongsen Mao; Weimin Yang; Jianchao Xia; Bin Zhang; Qingying Song; Qingling Chen

2005-01-01

50

Microstructure and properties of CVD tungsten carbide from tungsten hexafluoride and dimethyl ether  

SciTech Connect

Tungsten carbide was deposited from tungsten hexafluoride, dimethyl ether, and hydrogen using a horizontal, cold-wall reactor. The effects of substrate temperature, reactor pressure, and reagent ratio on the coating growth rate, morphology, composition, and microhardness were studied. Under most conditions, the solid deposit was primarily W[sub 3]C with minor amounts of W. The tungsten carbide growth rate data fit an Arrhenius rate expression for temperatures from 425 to 550 C and had an activation energy of 24 kcal/mol at 70 mmHg total pressure and a WF[sub 6]/DME ratio of 6.3. A variety of surface morphologies and microstructures were observed. The microhardness of the coated substrates increased with coating thickness to a maximum value of 2,400 kg/mm[sup 2].

Skaf, D.W.; Warner, A.W.; Dollahon, N.R.; Fargo, G.H. (Villanova Univ., PA (United States))

1994-12-01

51

Impact of DME-Diesel Fuel Blend Properties on Diesel Fuel Injection Systems. May 16, 2001 - February 15, 2004.  

National Technical Information Service (NTIS)

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 lubr...

2004-01-01

52

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

53

Laser-induced plasma in methane and dimethyl ether for flame ignition and combustion diagnostics  

NASA Astrophysics Data System (ADS)

In this paper we report the investigation of the laser-induced breakdown and ignition behaviour of methane/air and dimethyl ether (DME)/air mixtures. Moreover, the optical emission from the induced plasma is utilized for determining the mixture composition quantitatively by means of laser-induced breakdown spectroscopy (LIBS). To the best of the authors' knowledge, LIBS and laser ignition of DME have not been reported in literature before. The technique under investigation is finally employed for combustion diagnostics in laminar as well as turbulent flames. In the laminar premixed and non-premixed flames the LIBS spectra allow spatially resolved measurements of the equivalence ratio and enable studying the mixing of gases provided through the burner with the surrounding room air. In addition, the breakdown threshold of the applied laser pulse energy yields an estimate for the local temperature. In the turbulent cases single-shot LIBS spectra are recorded at fixed position allowing the derivation of local statistical fluctuations of the equivalence ratio in partially premixed jet flames. The results show that laser-induced breakdowns have a strong potential for flame diagnostics and, under suitable conditions, for the ignition of combustible mixtures.

Kiefer, J.; Tröger, J. W.; Li, Z. S.; Aldén, M.

2011-04-01

54

Pressure and temperature dependence of excess enthalpies of methanol + tetraethylene glycol dimethyl ether and methanol + polyethylene glycol dimethyl ether 250  

SciTech Connect

The excess molar enthalpies at 323.15 K, 373.15 K, and 423.15 K, at 8 MPa, are reported for the binary mixtures methanol + tetraethylene glycol dimethyl ether (TEGDME) and methanol + poly(ethylene glycol) dimethyl ether 250 (PEGDME 250). Excess molar enthalpies were determined with a Setaram C-80 calorimeter equipped with a flow mixing cell. For both systems, the excess enthalpies are positive over the whole composition range, increasing with temperature. The H{sup E}(x) curves are slightly asymmetrical, and their maxima are skewed toward the methanol-rich region. The excess enthalpies slightly change with the pressure, the sign of this change being composition-dependent. In the case of mixtures with TEGDME, the experimental H{sup E} values have been compared with those predicted with the Gmehling et al. version of UNIFAC (Dortmund) and the Nitta-Chao and DISQUAC group contribution models.

Lopez, E.R.; Coxam, J.Y.; Fernandez, J.; Grolier, J.P.E.

1999-12-01

55

Performance Characteristics of a DME Propellant Arcjet Thruster  

NASA Astrophysics Data System (ADS)

This paper describes the influence of cathode configuration on performance of an arcjet thruster using dimethyl ether (DME) propellant. DME, an ether compound, has suitable characteristics for a space propulsion system; DME is storable in a liquid state without being kept under a high pressure, and requires no sophisticated temperature management such as a cryogenic device. DME can be gasified and liquefied simply by adjusting temperature whereas hydrazine, a conventional propellant, requires an iridium-based particulate catalyst for its gasification. In this study, thrust of a 1-kW class DME arcjet thruster is measured at a discharge current of 13 A, DME mass flow rates ranging 15 to 60 mg/s under three cathode configurations: flat-tip rods of 2 and 4 mm in diam. and 4-mm-diam. rod having a cavity of 2 mm in diameter. Thrust measurements show that thrust is increased with propellant mass flow rate. Among the tested cathodes, the flat-tip rod of 4 mm in diam. with 55 mg/s DME flow rate yielded the highest performance: specific impulse of 330 s, thrust of 0.18 N, discharge power of 1400 W and specific power of 25 MJ/kg.

Kakami, Akira; Beeppu, Shinji; Maiguma, Muneyuki; Tachibana, Takeshi

56

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

57

Effects of amine organic groups as lattice in ZSM-5 on the hydrolysis of dimethyl ether.  

PubMed

The effects of doping amine to ZSM-5 on its catalytic activity for hydrolysis of dimethyl ether (DME) have been studied theoretically using Density Functional Theory with the embedded cluster ONIOM(M06/6-31G(d,p):UFF) model. Doping by amine to ZSM-5 yields two new active centers, namely the protonated Z[NH2] and non-protonated Z[NH] amine sites in addition to the normal Brønsted acid Z[OH] site. The reaction has two possible stepwise and concerted channels. The stepwise channel consists of two elementary steps; (i) the demethylation followed by (ii) the hydrolysis while the concerted channel involves in the demethylation and hydrolysis in a single step. We found that the reaction favors to proceed via the concerted channel at all three active centers. The results predict that the Z[OH] shows the best catalytic performance for the studied reaction. The Z[NH2] is not catalytically active due to the activation barriers are extremely high for both stepwise and concerted pathways. The demethylation step is energetically favorable over the Z[NH] site, however, the product methylamonium surface intermediate is too stable to be further converted to methanol. PMID:23681284

Meeprasert, Jittima; Jungsuttiwong, Siriporn; Truong, Thanh N; Namuangruk, Supawadee

2013-06-01

58

Industrial gas turbine combustion performance test of DME to use as an alternative fuel for power generation  

Microsoft Academic Search

DME (dimethyl ether, CH3OCH3) is both a good alternative fuel for transportation and power generation and an LPG substitute owing to its cleanliness, multi-source productivity and the ease with which it is transported. This study was conducted to verify whether DME is a good fuel for gas turbines and to identify potential problems in fuelling a commercial gas turbine with

Min Chul Lee; Seok Bin Seo; Jae Hwa Chung; Yong Jin Joo; Dal Hong Ahn

2009-01-01

59

Dimethyl ether-13C lab spectra up to 1.5THz (Koerber+, 2013)  

NASA Astrophysics Data System (ADS)

The interpretation of astronomical observations depends on the knowledge of accurate rest frequencies and intensities. The objective of this work is to provide spectroscopic data for the two 13C-isotopologues of dimethyl ether in the vibrational ground state. High-resolution rotational-torsional spectra of dimethyl ether-13C1 and dimethyl ether-13C2 have been measured in the laboratory covering frequencies up to 1.5THz. The analysis is based on an effective rotational Hamiltonian for molecules with two large amplitude motions. (2 data files).

Koerber, M.; Bisschop, S. E.; Endres, C. P.; Kleshcheva, M.; Pohl, R. W. H.; Klein, A.; Lewen, F.; Schlemmer, S.

2013-09-01

60

Development of alternative fuels from coal derived syngas. Topical report: Task 2.2, Demonstration of a one-step slurry-phase process for the production of dimethyl ether/methanol mixtures at the LaPorte Alternative Fuels Development Unit  

SciTech Connect

This report documents engineering, modification, and operations efforts of demonstration of dimethyl-ether/methanol coproduction in a slurry-phase reactor, carried out in a 2-ft diameter bubble column reactor. Equipment modifications made it possible to remove the product DME and by-product CO{sub 2} from the reactor effluent. Coproduction of dimethyl-ether (DME) and methanol (MeOH) was accomplished in the slurry reactor by physically mixing two different catalysts. The catalyst used to produce MeOH from syngas was manufactured by BASF (type S3-86); the catalyst used to convert MeOH to DME was Catapal {gamma}-alumina. Ratio of MeOH to DME catalysts determined the selectivity towards DME. The demonstration sought to study effect of cocatalyst ratio on product selectivity. Three different proportions of DME catalyst were examined: 0, 6.6, and 19.3 wt % alumina. At each catalyst proportion, the plant was operated at two different gas space velocities. Some process variables were maintained at fixed conditions; most important variables included: reactor temperature (482F), reactor pressure (750 psig), and reactor feed gas composition (35% H{sub 2}, 51% CO,13% CO{sub 2} 1% other, nominal-molar basis).

Not Available

1993-06-01

61

Carbon dioxide tolerance in the single-stage liquid-phase synthesis of dimethyl ether  

SciTech Connect

In the liquid-phase dimethyl ether process, methanol synthesis catalyst (Cu/ZnO/Al{sub 2}O{sub 3}) and methanol dehydration catalyst ({gamma}-alumina) are slurred in an inert liquid medium. The inert liquid medium used in this investigation is a white mineral oil, Witco-40. This multiphase reaction is conducted in a mechanically agitated slurry reactor. In this process, syngas conversion can be significantly improved by coproduction of dimethyl ether along with methanol. The coproduction strategy improves the thermodynamic and kinetic environment of the reaction system. The effects of catalyst loadings in the slurry and the roles played by carbon dioxide in dimethyl ether synthesis were studied by conducting kinetic experiments. The liquid-phase dimethyl ether synthesis process exhibits higher carbon dioxide tolerance as compared to the liquid-phase methanol synthesis process, whose optimal carbon dioxide concentration in the unbalanced syngas feed is around 8%. These results have been experimentally confirmed.

Sardesai, A.; Gunda, A.; Tartamella, T.; Lee, S.

2000-01-01

62

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

Microsoft Academic Search

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)

Troy Allen Semelsberger

2005-01-01

63

Design of a Pulse Injector for DME Propellant  

NASA Astrophysics Data System (ADS)

Recently, a pulsed plasma thruster (PPT), which has advantages such as smallness, lightweight and low power consumption, has attracted attention again for the application to small satellites. Liquid propellant like water or alcohol provides higher specific impulse in comparison with conventional Teflon propellant. Nevertheless, water and alcohol propellants have problems: higher freezing point or contamination to satellites by the exhaust gas. In this study, we propose to apply DME (Di-methyl ether) to the PPT's propellant. DME can be stored as liquid, and requires no pressurant because DME has a vapor pressure of 0.6 MPa at 298 K. DME would also be potentially usable as heat transfer media, coolant, working fluid of heat pipe etc. We have designed and tested a prototyped pulse injector supplying liquid DME to discharge channels of the PPTs. Experimental results showed that the pulse injector successfully injected liquefied DME of 1.16 mg/shot, which is equivalent to the mass shot of a high power class PPT. The shape of injected liquid was dependent on the duration of the gating-pulse applied to the injector; a group of droplets were provided with a 20 ms gating-pulse duration, and a single stream with 25 ms or longer gating-pulse duration.

Fukunaga, Masato; Kakami, Akira; Tachibana, Takeshi

64

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

65

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

66

Halogen bond and free internal rotation: the microwave spectrum of CF3Cl-dimethyl ether.  

PubMed

The rotational spectra of two isotopologues of the molecular complex CF3Cl-dimethyl ether have been measured with pulsed jet Fourier transform microwave spectroscopy. The rotational spectrum encodes information on the global minimum configuration, stabilized by a Cl···O halogen bond, and on the almost free rotation of the -CF3 group. PMID:24400718

Evangelisti, Luca; Feng, Gang; Gou, Qian; Grabow, Jens-Uwe; Caminati, Walther

2014-01-23

67

Dehydration of methanol over Nordstrandite based catalysts for dimethyl ether synthesis  

Microsoft Academic Search

This study focused on the investigation of Nordstrandite as a catalyst for dehydration of methanol to dimethyl ether synthesis. The structure phase of Nordstrandite has been changed to boehmite and ?-Al2O3 in sequence via calcinations at various temperatures. Moreover, the properties of the samples have been varied significantly with heat treatment. The number of acid sites of Nordstrandite was much

Chang Won Seo; Kwang Deok Jung; Kwan Young Lee; Kye Sang Yoo

2009-01-01

68

Role of dehydration catalyst acid properties on one-step DME synthesis over physical mixtures  

Microsoft Academic Search

The direct synthesis of dimethyl ether (DME) was studied in a continuous high-pressure unit composed basically of a Berty reactor and on-line gas chromatograph. A commercial methanol synthesis catalyst and some solid-acid catalysts (alumina, HZSM-5, tungsten–zirconia and sulfated-zirconia) were used as physical mixtures. The dehydration catalysts were characterised by pyridine adsorption followed by IR spectroscopy and tested in the methanol

F. S. Ramos; A. M. Duarte de Farias; L. E. P. Borges; J. L. Monteiro; M. A. Fraga; E. F. Sousa-Aguiar; L. G. Appel

2005-01-01

69

The influence of different methanol synthesis catalysts on direct synthesis of DME from syngas  

Microsoft Academic Search

Methanol synthesis catalysts based on Cu–Zn–Al prepared under different precipitation conditions with the use of Zr or not as a promoter were studied in the direct synthesis of dimethyl ether (DME) using H-ferrierite as a dehydration component. Samples prepared under high supersaturation conditions showed textural and structural changes without any relation to the CO conversion. Samples containing zirconium favored an

J. H. Flores; D. P. B. Peixoto; L. G. Appel; R. R. de Avillez; M. I. Pais da Silva

2011-01-01

70

Partial oxidation of dimethyl ether using the structured catalyst Rh/Al2O3/Al prepared through the anodic oxidation of aluminum.  

PubMed

The partial oxidation of dimethyl ether (DME) was investigated using the structured catalyst Rh/Al2O3/Al. The porous Al2O3 layer was synthesized on the aluminum plate through anodic oxidation in an oxalic-acid solution. It was observed that about 20 nm nanopores were well developed in the Al2O3 layer. The thickness of Al2O3 layer can be adjusted by controlling the anodizing time and current density. After pore-widening and hot-water treatment, the Al2O3/Al plate was calcined at 500 degrees C for 3 h. The obtained delta-Al2O3 had a specific surface area of 160 m2/g, making it fit to be used as a catalyst support. A microchannel reactor was designed and fabricated to evaluate the catalytic activity of Rh/Al2O3/Al in the partial oxidation of DME. The structured catalyst showed an 86% maximum hydrogen yield at 450 degrees C. On the other hand, the maximum syngas yield by a pack-bed-type catalyst could be attained by using a more than fivefold Rh amount compared to that used in the structured Rh/Al2O3/Al catalyst. PMID:22121705

Yu, B Y; Lee, K H; Kim, K; Byun, D J; Ha, H P; Byun, J Y

2011-07-01

71

Study of a self quenching streamer mode in pure gases of DME and isobutane  

NASA Astrophysics Data System (ADS)

A self quenching streamer (SQS), or limited streamer mode has been studied in single wire chambers with cross-sections 12×12 mm2 and wire diameters 15, 25 and 50 ?m. Chambers were filled with either pure dimethyl ether (DME) or isobutane gases and irradiated with 148Gd alpha and 55Fe X-ray sources. Clear transitions from a proportional to 100% SQS mode were observed on all three diameter wires with both gases irradiated with alpha particles. Double SQS discharges due to inclined tracks observed in DME gas allowed an estimation of a streamer size along the wire of less than 1 mm. The second SQS discharge appears less than 1 mm from the first within about 500 ns. Charge spectra obtained with DME irradiated with 55Fe X-rays might also be interpreted as a transition to a SQS mode, although no direct evidence of that was seen in the observed pulse shapes.

Davydov, Yu. I.; Openshaw, R.

2006-02-01

72

Reaction of dimethyl ether with hydroxyl radicals: kinetic isotope effect and prereactive complex formation.  

PubMed

The kinetic isotope effect of the reactions OH + CH3OCH3 (DME) and OH + CD3OCD3 (DME-d6) was experimentally and theoretically studied. Experiments were carried out in a slow-flow reactor at pressures between 5 and 21 bar (helium as bath gas) with production of OH by laser flash photolysis of HNO3 and time-resolved detection of OH by laser-induced fluorescence. The temperature dependences of the rate coefficients obtained can be described by the following modified Arrhenius expressions: k(OH+DME) = (4.5 ± 1.3) × 10(-16) (T/K)(1.48) exp(66.6 K/T) cm(3) s(-1) (T = 292-650 K, P = 5.9-20.9 bar) and k(OH+DME-d6) = (7.3 ± 2.2) × 10(-23) (T/K)(3.57) exp(759.8 K/T) cm(3) s(-1) (T = 387-554 K, P = 13.0-20.4 bar). A pressure dependence of the rate coefficients was not observed. The agreement of our experimental results for k(OH+DME) with values from other authors is very good, and from a fit to all available literature data, we derived the following modified Arrhenius expression, which reproduces the values obtained in the temperature range T = 230-1500 K at pressures between 30 mbar and 21 bar to better than within ±20%: k(OH+DME) = 8.45 × 10(-18) (T/K)(2.07) exp(262.2 K/T) cm(3) s(-1). For k(OH+DME-d6), to the best of our knowledge, this is the first experimental study. For the analysis of the reaction pathway and the kinetic isotope effect, potential energy diagrams were calculated by using three different quantum chemical methods: (I) CCSD(T)/cc-pV(T,Q)Z//MP2/6-311G(d,p), (II) CCSD(T)/cc-pV(T,Q)Z//CCSD/cc-pVDZ, and (III) CBS-QB3. In all three cases, the reaction is predicted to proceed via a prereaction OH-ether complex with subsequent intramolecular hydrogen abstraction and dissociation to give the methoxymethyl radical and water. Overall rate coefficients were calculated by assuming a thermal equilibrium between the reactants and the prereaction complex and by calculating the rate coefficients of the hydrogen abstraction step from canonical transition state theory. The results based on the molecular data from methods (I) and (II) showed a satisfactory agreement with the experimental values, which indicates that the pre-equilibrium assumption is reasonable under our conditions. In the case of method (III), the isotope effect was significantly underpredicted. The reason for this discrepancy was identified in a fundamentally differing reaction coordinate. Obviously, the B3LYP functional applied in method (III) for geometry and frequency calculations is inadequate to describe such systems, which is in line with earlier findings of other authors. PMID:23914942

Bänsch, Cornelie; Kiecherer, Johannes; Szöri, Milan; Olzmann, Matthias

2013-09-01

73

Effect of thermodynamic history on secondary relaxation in glassy phenolphthalein-dimethyl-ether  

NASA Astrophysics Data System (ADS)

We present a study of the intermediate secondary relaxation process of phenolphthalein-dimethyl-ether. Though this process is intramolecular in nature, it reveals pronounced pressure dependence. Moreover, its relaxation frequency and intensity exhibit pronounced dependence on the thermal history followed during vitrification. These results suggest that the nonequilibrium nature of the glassy state influences this secondary relaxation principally through the dependence on the specific volume.

Prevosto, D.; Capaccioli, S.; Lucchesi, M.; Rolla, P. A.; Paluch, M.; Pawlus, S.

2006-03-01

74

Effect of surface hydroxyls on DME and methanol adsorption over ?-Al(2)O(3) (hkl) surfaces and solvent effects: a density functional theory study.  

PubMed

Methanol and dimethyl ether (DME) adsorption over clean and hydrated ?-Al(2)O(3)(100) and (110) surfaces was studied by using density functional theory (DFT) combined with conductor-like solvent model (COSMO) in gas phase and liquid paraffin. On clean ?-Al(2)O(3) (100) and (110) surfaces, DME and methanol preferentially interact with Al3 and Al1 of the ?-Al(2)O(3)(110) and (100) surfaces, respectively. On hydrated ?-Al(2)O(3)(100) and (110) surfaces, the OH group can influence the adsorptive behavior of DME and methanol. The Al3 and Al1 active sites of the hydrated (110) and (100) surfaces are inactivated due to hydroxyl influence, respectively. Compared to the adsorption energies of DME and methanol adsorption over the clean and hydrated (110) and (100) surfaces in gas phase and liquid paraffin, it is found that the solvent effects can slightly reduce adsorptive ability. PMID:22763911

Zuo, Zhi-Jun; Han, Pei-De; Hu, Jian-Shui; Huang, Wei

2012-12-01

75

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

76

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

77

Densities, viscosities, and enthalpies of mixing of the binary system methanol + polyethylene glycol 250 dimethyl ether at 303. 15 K  

SciTech Connect

Research on new working fluid pairs for use in absorption refrigeration systems and heat transformers continues. Densities, kinematic viscosities, and excess molar enthalpies have been determined for methanol + polyethylene glycol 250 dimethyl ether at 303.15 K over the entire range of composition and at atmospheric pressure. Experimental viscosities were correlated by the McAllister, Stephan, Soliman, and Marshall correlations.

Esteve, X.; Patil, K.R.; Chaudhari, S.K.; Coronas, A. (Univ. Rovira i Virgili, Tarragona (Spain). Dept. de Quimica); Boer, D. (ENSIGC, Toulouse (France))

1994-10-01

78

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

79

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

80

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.

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

2013-01-01

81

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

82

Organic?Inorganic Nanocomposite Membranes as High Temperature Proton Exchange Membranes for a Direct Dimethyl Ether Fuel Cell Application  

Microsoft Academic Search

Nafion\\/poly(phenylmethyl silsequioxane) (PPSQ)\\/calcium hydroxyphosphate (CHP) and Nafion\\/PPSQ composite membranes are fabricated using homogeneous dispersive mixing and a solvent casting method for direct dimethyl ether fuel cell (DDMEFC) applications for use above 100°C. The recast composite membranes were characterized by means of scanning electron microscopy (SEM), X?ray diffraction (XRD) analysis, and thermogravimetry (TGA). The results showed that PPSQ and CHP are

Yongku Kang; Jae Wook Lee

2007-01-01

83

Laboratory rotational spectra of the dimethyl ether 13C-isotopologues up to 1.5 THz  

NASA Astrophysics Data System (ADS)

Context. Dimethyl ether is found in high abundance in the interstellar medium. Owing to its strong and dense spectrum throughout the entire microwave and terahertz regime, it contributes to the spectral confusion in astronomical line surveys. The great sensitivity of new observatories like ALMA enhances the need for reliable spectroscopic data, especially for isotopic species of abundant molecules. In addition, the study of the interstellar 12C/13C isotopic ratio can be used as a tracer of the formation process of a molecular species, and thus it gives insight into the chemical evolution of the observed region. Aims: The interpretation of astronomical observations depends on the knowledge of accurate rest frequencies and intensities. The objective of this work is to provide spectroscopic data for the two 13C-isotopologues of dimethyl ether in the vibrational ground state. Methods: High-resolution rotational-torsional spectra of 12CH3O13CH3 and (13CH3)2O have been measured in the laboratory covering frequencies up to 1.5 THz. The analysis is based on an effective rotational Hamiltonian for molecules with two large-amplitude motions. Results: Predictions of the complete ground state rotational spectrum of dimethyl ether-13C1 and -13C2 up to 2 THz are presented with accuracies better than 1 MHz. Based on the laboratory work, transitions of 12CH3O13CH3 dimethyl ether have been detected for the first time in a large submillimeter line survey of the high-mass star forming region G327.3-0.6 performed with the APEX telescope. Full Tables 5 and 6 are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/558/A112

Koerber, M.; Bisschop, S. E.; Endres, C. P.; Kleshcheva, M.; Pohl, R. W. H.; Klein, A.; Lewen, F.; Schlemmer, S.

2013-10-01

84

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

Microsoft Academic Search

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

1993-01-01

85

High-resolution Expanded Very Large Array Image of Dimethyl Ether (CH3)2O in Orion-KL  

NASA Astrophysics Data System (ADS)

We report the first subarcsecond (0farcs65 × 0farcs51) image of the dimethyl ether molecule, (CH3)2O, 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 61, 5-60, 6, EE (E 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 (HCOOCH3), 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.; Wootten, H. A.; Remijan, A. J.; Brouillet, N.; Wilson, T. L.; Despois, D.; Baudry, A.

2011-09-01

86

Matrix infrared spectroscopic and density functional theoretical investigations on thorium and uranium atom reactions with dimethyl ether.  

PubMed

Reactions of laser-ablated thorium and uranium atoms with dimethyl ether were investigated using matrix isolation infrared spectroscopy. Four types of reaction products for both uranium and thorium were identified using deuterium substituted samples as well as density functional frequency and energy calculations. Ground state uranium and thorium atoms react with dimethyl ether spontaneously to give the M(CH(3)OCH(3)) complexes (M = Th, U) on annealing, which are predicted to have C(2v) symmetry with triplet (Th) and quintet (U) ground states. Subsequent visible irradiation produces the divalent CH(3)OThCH(3) and CH(3)OUCH(3) insertion products with singlet and quintet states lowest in energy. Further UV irradiation induces isomerization of the CH(3)OMCH(3) molecules to the (CH(3))(2)MO isomers with M=O double bonds and pyramidal structures. In the presence of another dimethyl ether reagent, evidence for (CH(3)O)(2)M(CH(3))(2) molecules is also produced upon UV irradiation. PMID:21769368

Gong, Yu; Andrews, Lester

2011-11-14

87

Development of an optical gas leak sensor for detecting ethylene, dimethyl ether and methane.  

PubMed

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

88

Mono-deuterated dimethyl ether: laboratory spectrum up to 1 THz. Torsion-rotational spectrum within the vibrational ground-state for the symmetric and asymmetric conformers and first detection in IRAS 16293-2422  

NASA Astrophysics Data System (ADS)

Context. Dimethyl ether is one of the most abundant complex organic molecules (COMs) in star-forming regions. Like other COMs, its formation process is not yet clearly established, but the relative abundances of its deuterated isotopomers may provide crucial hints in studying its chemistry and tracing the source history. The mono-deuterated species (CHDOCH) is still a relatively light molecule compared to other COMs. Its spectrum is the most intense in the THz domain in the 100-150 K temperature regime, tracing the inner parts of the low-mass star-forming region. Therefore, it is necessary to measure and assign its transitions in this range in order to be able to compute accurate predictions required by astronomical observations, in particular with the telescope operating in the submm range, such as ALMA. Aims: We present the analysis of mono-deuterated dimethyl ether in its ground-vibrational state, based on an effective Hamiltonian for an asymmetric rotor molecules with internal rotors. The analysis covers the frequency range 150-990 GHz. Methods: The laboratory rotational spectrum of this species was measured with a submillimeter spectrometer (50-990 GHz) using solid-state sources. For the astronomical detection, we used the IRAM 30 m telescope to observe a total range of 27 GHz, in 4 frequency bands from 100 GHz to 219 GHz. Results: New sets of spectroscopic parameters have been determined by a least squares fit with the ERHAM code for both conformers. These parameters have permitted the first identification in space of both mono-deuterated DME isomers via detection of twenty transitions in the solar-type protostar IRAS 16293-2422 with the IRAM 30 m telescope. The DME deuteration ratio in this source appears as high as observed for methanol and formaldehyde, two species known to play an important role in the COMs formation history. Full Tables A.1, A.2, B.1, and B.2, which respectively give the measured (in laboratory) and predicted frequencies, are only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/552/A117

Richard, C.; Margulès, L.; Caux, E.; Kahane, C.; Ceccarelli, C.; Guillemin, J.-C.; Motiyenko, R. A.; Vastel, C.; Groner, P.

2013-04-01

89

Catalyst Activity Maintenance for the Liquid Phase Synthesis Gas-to-Dimethyl Ether Process.  

National Technical Information Service (NTIS)

At the heart of the single-step liquid phase syngas-to-DME process (LPDME) 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 (...

X. D. Peng

2002-01-01

90

CCSD(T) study of dimethyl-ether infrared and Raman spectra.  

PubMed

CCSD(T) state-of-the-art ab initio calculations are used to determine a vibrationally corrected three-dimensional potential energy surface of dimethyl-ether depending on the two methyl torsions and the COC bending angle. The surface is employed to obtain variationally the lowest vibrational energies that can be populated at very low temperatures. The interactions between the bending and the torsional coordinates are responsible for the displacements of the torsional overtone bands and several combination bands. The effect of these interactions on the potential parameters is analyzed. Second order perturbation theory is used as a help for the understanding of many spectroscopic parameters and to obtain anharmonic fundamentals for the 3N - 9 neglected modes as well as the rotational parameters. To evaluate the surface accuracy and to verify previous assignments, the calculated vibrational levels are compared with experimental data corresponding to the most abundant isotopologue. The surface has been empirically adjusted for understanding the origin of small divergences between ab initio calculations and experimental data. Our calculations confirm previous assignments and show the importance of including the COC bending degree of freedom for computing with a higher accuracy the excited torsional term values through the Fermi interaction. Besides, this work shows a possible lack of accuracy of some available experimental transition frequencies and proposes a new assignment for a transition line. As an example, the transition 100 ? 120 has been computed at 445.93 cm(-1), which is consistent with the observed transition frequency in the Raman spectrum at 450.5 cm(-1). PMID:21999111

Villa, M; Senent, M L; Dominguez-Gomez, R; Alvarez-Bajo, O; Carvajal, M

2011-11-24

91

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

92

Extraction of chili, black pepper, and ginger with near-critical CO2, propane, and dimethyl ether: analysis of the extracts by quantitative nuclear magnetic resonance.  

PubMed

Ginger, black pepper, and chili powder were extracted using near-critical carbon dioxide, propane, and dimethyl ether on a laboratory scale to determine the overall yield and extraction efficiency for selected pungent components. The temperature dependency of extraction yield and efficiency was also determined for black pepper and chili using propane and dimethyl ether. The pungency of the extracts was determined by using an NMR technique developed for this work. The volatiles contents of ginger and black pepper extracts were also determined. Extraction of all spice types was carried out with acetone to compare overall yields. Subcritical dimethyl ether was as effective at extracting the pungent principles from the spices as supercritical carbon dioxide, although a substantial amount of water was also extracted. Subcritical propane was the least effective solvent. All solvents quantitatively extracted the gingerols from ginger. The yields of capsaicins obtained by supercritical CO(2) and dimethyl ether were similar and approximately double that extracted by propane. The yield of piperines obtained by propane extraction of black pepper was low at approximately 10% of that achieved with dimethyl ether and CO(2), but improved with increasing extraction temperature. PMID:12903935

Catchpole, Owen J; Grey, John B; Perry, Nigel B; Burgess, Elaine J; Redmond, Wayne A; Porter, Noel G

2003-08-13

93

Correlation between urinary methoxyacetic acid and exposure of ethylene glycol dimethyl ether in a lithium battery plant  

Microsoft Academic Search

Objective  To examine the correlation between airborne ethylene glycol dimethyl ether (EGdiME) exposures and the urinary methoxyacetic\\u000a acid (MAA) and to approach the issue of a permissible exposure limit for EGdiME.\\u000a \\u000a \\u000a \\u000a Methods  The survey was conducted on Thursday. Workers occupationally exposed to EGdiME, as well as nonexposed controls, were studied\\u000a in combination with one of the authors, who was coincidentally exposed to

Kozo Yokota; Hiroshi Ueno; Naoko Ikeda; Yasushi Johyama; Hiromi Michitsuji; Seiji Yamada

2007-01-01

94

Intrinsic kinetics of one-step dimethyl ether synthesis from hydrogen-rich synthesis gas over bi-functional catalyst  

Microsoft Academic Search

The reaction kinetics of the dimethyl ether synthesis from hydrogen-rich synthesis gas over bi-functional catalyst was investigated\\u000a using an isothermal integral reactor at 220–260°C temperature, 3–7 MPa pressure, and 1,000–2,500 mL\\/g·h space velocity. The\\u000a H2\\/CO ratio of the synthetic gas was chosen between 3 : 1 and 6 : 1. The bi-functional catalyst was prepared by physically mixing\\u000a commercial CuO\\/ZnO\\/Al2O3

Chengyuan Cheng; Haitao Zhang; Weiyong Ying; Dingye Fang

2011-01-01

95

Effect of the hybrid catalysts preparation method upon direct synthesis of dimethyl ether from synthesis gas  

Microsoft Academic Search

Direct synthesis of DME from synthesis gas attains more attention recently due to higher conversion and lower cost in comparison to dehydration of the methanol. In this work Synthesis gas To Dimethylether (STD) conversion was examined on various hybrid catalysts prepared by seven different methods. These catalysts had the same general form as CuO\\/ZnO\\/Al2O3 with theoretical weight ratio 31\\/16\\/53, respectively.

G. R. Moradi; S. Nosrati; F. Yaripor

2007-01-01

96

High carbon dioxide solubilities in imidazolium-based ionic liquids and in poly(ethylene glycol) dimethyl ether.  

PubMed

This work is focused on the possible capture of carbon dioxide using ionic liquids (ILs). Such solvents are gaining special attention because the efficiency of many processes can be enhanced by the judicious manipulation of their properties. The absorption of greenhouse gases can be enhanced by the basic character of the IL. In this work, these characteristics are evaluated through the study of the gas-liquid equilibrium of four imidazolium-based ILs: 1-butyl-3-methylimidazolium tetrafluoroborate [BMIM][BF(4)], 1-butyl-3-methylimidazolium thiocyanate [BMIM][SCN], 1,3-dimethylimidazolium methylphosphonate [DMIM][MP], and 1,3-diethoxyimidazolium bis(trifluoromethylsulfonyl)imide [(ETO)(2)IM][Tf(2)N] with CO(2) at temperatures up to 373 K and pressures up to 300 bar. Solubility of carbon dioxide in poly(ethylene glycol) dimethyl ether, component of selexol, was also measured to evaluate the capture's efficiency of ionic liquids. Experimental data indicate that 67 to 123 g of CO(2) can be absorbed per kg of ionic liquid and 198 g per kg of poly(ethylene glycol) dimethyl ether. PMID:20853857

Revelli, Anne-Laure; Mutelet, Fabrice; Jaubert, Jean-Noël

2010-10-14

97

High-resolution Evla Imaging Of Dimethyl Ether (ch_{3})_{2}o In Orion--kl  

NASA Astrophysics Data System (ADS)

We report the first sub-arc second (0.65" x 0.51") image of the dimethyl ether (CH3)2O molecule toward the Orion Kleinmann-Low nebula (Orion--KL). The observations have been carried at 43.4 GHz with the Expanded Very Large Array (EVLA). The distribution of the lower energy transition 6(1,5) - 6(0,6), EE; Eu = 21K mapped in this study is in excellent agreement with the published dimethyl ether and methyl formate emission images obtained with a lower resolution. The main emission peaks are observed toward the Compact Ridge and Hot Core southwest components, as the northern parts of the Compact Ridge and in an intermediate position between the Compact Ridge and the Hot Core. 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, molecular line imaging.

Wootten, Al; Favre, C.; Remijan, A.; Brouillet, N.; Wilson, T.; Despois, D.; Baudry, A.

2011-05-01

98

Single-Step Syngas-to-Distillates (S2D) Synthesis via Methanol and Dimethyl Ether Intermediates: Final Report  

SciTech Connect

The objective of the work was to enhance price-competitive, synthesis gas (syngas)-based production of transportation fuels that are directly compatible with the existing vehicle fleet (i.e., vehicles fueled by gasoline, diesel, jet fuel, etc.). To accomplish this, modifications to the traditional methanol-to-gasoline (MTG) process were investigated. In this study, we investigated direct conversion of syngas to distillates using methanol and dimethyl ether intermediates. For this application, a Pd/ZnO/Al2O3 (PdZnAl) catalyst previously developed for methanol steam reforming was evaluated. The PdZnAl catalyst was shown to be far superior to a conventional copper-based methanol catalyst when operated at relatively high temperatures (i.e., >300°C), which is necessary for MTG-type applications. Catalytic performance was evaluated through parametric studies. Process conditions such as temperature, pressure, gas-hour-space velocity, and syngas feed ratio (i.e., hydrogen:carbon monoxide) were investigated. PdZnAl catalyst formulation also was optimized to maximize conversion and selectivity to methanol and dimethyl ether while suppressing methane formation. Thus, a PdZn/Al2O3 catalyst optimized for methanol and dimethyl ether formation was developed through combined catalytic material and process parameter exploration. However, even after compositional optimization, a significant amount of undesirable carbon dioxide was produced (formed via the water-gas-shift reaction), and some degree of methane formation could not be completely avoided. Pd/ZnO/Al2O3 used in combination with ZSM-5 was investigated for direct syngas-to-distillates conversion. High conversion was achieved as thermodynamic constraints are alleviated when methanol and dimethyl are intermediates for hydrocarbon formation. When methanol and/or dimethyl ether are products formed separately, equilibrium restrictions occur. Thermodynamic relaxation also enables the use of lower operating pressures than what would be allowed for methanol synthesis alone. Aromatic-rich hydrocarbon liquid (C5+), containing a significant amount of methylated benzenes, was produced under these conditions. However, selectivity control to liquid hydrocarbons was difficult to achieve. Carbon dioxide and methane formation was problematic. Furthermore, saturation of the olefinic intermediates formed in the zeolite, and necessary for gasoline production, occurred over PdZnAl. Thus, yield to desirable hydrocarbon liquid product was limited. Evaluation of other oxygenate-producing catalysts could possibly lead to future advances. Potential exists with discovery of other types of catalysts that suppress carbon dioxide and light hydrocarbon formation. Comparative techno-economics for a single-step syngas-to-distillates process and a more conventional MTG-type process were investigated. Results suggest operating and capital cost savings could only modestly be achieved, given future improvements to catalyst performance. Sensitivity analysis indicated that increased single-pass yield to hydrocarbon liquid is a primary need for this process to achieve cost competiveness.

Dagle, Robert A.; Lebarbier, Vanessa MC; Lizarazo Adarme, Jair A.; King, David L.; Zhu, Yunhua; Gray, Michel J.; Jones, Susanne B.; Biddy, Mary J.; Hallen, Richard T.; Wang, Yong; White, James F.; Holladay, Johnathan E.; Palo, Daniel R.

2013-11-26

99

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

100

Solubilizing and Hydrotropic Properties of Isosorbide Monoalkyl- and Dimethyl-Ethers  

Microsoft Academic Search

Isosorbide is a diol readily obtained from starch that can be used as a polar building block for the synthesis of derivatives\\u000a ranging from solvents to surfactants: dimethyl isosorbide (DMI) is a “sustainable solvent” already on the market, used notably\\u000a in cosmetic and pharmaceutical formulations; monoalkyl derivatives of isosorbide are non-ionic hydrotropes that could be potential\\u000a substitutes to short-chain glycol

Morgan Durand; Ying Zhu; Valérie Molinier; Thierry Féron; Jean-Marie Aubry

2009-01-01

101

Signal shape and charge sharing between electrodes of GEM in dimethyl ether  

NASA Astrophysics Data System (ADS)

We have performed a systematic investigation of the gain properties of the GEM foil made from copper-clad liquid crystal polymer insulator (LCP-GEM), which will be used for a satellite mission. We have measured the gain curve of LCP-GEM in pure DME at 190 Torr, and achieved a gain of 3 × 104 at an applied high voltage of 605 V between the LCP-GEM electrodes with a thickness of 100 ?m. The charge sharing between the GEM electrodes and readout pad were measured as a function of drift (Ed) or induction (Ei) field. We found that the parallel plate multiplication occurred between the bottom electrode of LCP-GEM and the readout pad above Ei = 6 kV, and the amount of charge collected in each electrode was almost constant with Ed. We investigated the signal shape obtained in each electrode and found that the rise time of signals was explained as induced charge by moving ions and electrons.

Takeuchi, Y.; Tamagawa, T.; Asami, F.; Yoshikawa, A.; Iwahashi, T.; Konami, S.; Iwakiri, W.

2012-03-01

102

Tunnelling motion of HF between the two oxygen lone pairs in the dimethyl ether-hydrogen fluoride complex: a pure rotational study.  

PubMed

The rotational spectrum of the dimethyl ether-hydrogen fluoride complex was assigned by millimetre-wave free-jet absorption spectroscopy. Fine details of the spectrum were resolved by FT microwave molecular-beam spectroscopy. The HF group acts as a proton donor and tunnels at a rate of 44178.2(7) MHz between the two oxygen lone pairs, which corresponds to an inversion barrier of 0.17 (1) kcal mol-1. The barrier to internal rotation of the two methyl groups is about 25% lower relative to the isolated ether. PMID:15067870

Ottaviani, Paolo; Caminati, Walther; Velino, Biagio; Blanco, Susana; Lesarri, Alberto; López, Juan C; Alonso, José L

2004-03-19

103

Improvement in the catalyst activity for direct synthesis of dimethyl ether from synthesis gas through enhancing the dispersion of CuO\\/ZnO\\/?-Al 2O 3 in hybrid catalysts  

Microsoft Academic Search

Based on the knowledge of the mechanisms of methanol synthesis and methanol dehydration, it was predicted that if the dispersion of CuO\\/ZnO\\/?-Al2O3 in hybrid catalysts for direct synthesis of dimethyl ether from synthesis gas was enhanced, the formation rate of dimethyl ether would be increased. In order to justify the prediction, five preparation methods, including two mechanical mixing ones and

J.-L. Li; X.-G. Zhang; T. Inui

1996-01-01

104

BINARY AND MULTICOMPONENT VAPOR-LIQUID EQUILIBRIA OF SYNTHESIS GAS COMPONENTS, METHANOL AND WATER WITH TETRA ETHYLENE GLYCOL DIMETHYL ETHER (TETRAGLYME)  

Microsoft Academic Search

Binary and multicomponent vapor-liquid equilibria of synthesis gas components (H2, CO, CH4, and CO2), methanol and water with tetraethylene glycol dimethyl ether (tetraglyme) were studied experimentally at temperatures (473–513 K) and pressures (5.3–10.4 MPa) typical of the conventional vapor phase methanol synthesis. Both vapor and liquid phases were sampled directly and analyzed by gas chromatography. Solubilities were expressed in terms of equilibrium

PANKAJ KHOSLA; CHANDRASEKHAR KRISHNAN; J. RICHARD ELLIOTT Jr; J. M. BERTY

1991-01-01

105

Electrochemical Investigation of Li–Al Anodes in Oligo(ethylene glycol) Dimethyl Ether/LiPF6  

SciTech Connect

1 M LiPF{sub 6} dissolved in oligo(ethylene glycol) dimethyl ether with a molecular weight 500 g mol{sup -1} was investigated as a new electrolyte (OEGDME500, 1 M LiPF{sub 6}) for metal deposition and battery applications. At 25 C a conductivity of 0.48 x 10{sup -3} S cm{sup -1} was obtained and at 85 C, 3.78 x 10{sup -3} S cm{sup -1}. The apparent activation barrier for ionic transport was evaluated to be 30.7 kJ mol{sup -1}. OEGDME500, 1 M LiPF{sub 6} allows operating temperature above 100 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 280 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.

Zhou, Y.N.; Yang, X.; Wang, X.J.; Lee, H.S.; Nam, K.W.; Haas, O.

2010-11-01

106

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

107

Improper or classical hydrogen bonding? A comparative cryosolutions infrared study of the complexes of HCClF(2), HCCl(2)F, and HCCl(3) with dimethyl ether.  

PubMed

Complexes of haloforms of the type HCCl(n)F(3-)(n) (n = 1-3) with dimethyl ether have been studied in liquid argon and liquid krypton, using infrared spectroscopy. For the haloform C[bond]H stretching mode, the complexation causes blue shifts of 10.6 and 4.8 cm(-1) for HCClF(2) and HCCl(2)F, respectively, while for HCCl(3) a red shift of 8.3 cm(-1) is observed. The ratio of the band areas of the haloform C[bond]H stretching in complex and monomer was determined to be 0.86(4) for HCClF(2), 33(3) for HCCl(2)F, and 56(3) for HCCl(3). These observations, combined with those for the HCF(3) complex with the same ether (J. Am. Chem. Soc. 2001, 123, 12290), have been analyzed using ab initio calculations at the MP2[double bond]FC/6-31G(d) level, and using some recent models for improper hydrogen bonding. Ab initio calculations on the haloforms embedded in a homogeneous electric field to model the influence of the ether suggest that the complexation shift of the haloform C[bond]H stretching is largely explained by the electric field effect induced by the electron donor in the proton donor. The model calculations also show that the electric field effect accounts for the observed intensity changes of the haloform C[bond]H stretches. PMID:12071758

Delanoye, Sofie N; Herrebout, Wouter A; van der Veken, Benjamin J

2002-06-26

108

Theoretical study of the O···Cl interaction in fluorinated dimethyl ethers complexed with a Cl atom: is it through a two-center-three-electron bond?  

PubMed

Theoretical investigations are carried out on the interaction between fluorinated dimethyl ethers (FDME, nF = 0-4) and the Cl atom. Short intermolecular O···Cl distances between 2.401 and 2.938 Å reveal the formation of a new class of complexes. The interaction energies calculated with the G2(MP2) method range between -9.1 (nF = 4) and -26.0 (nF = 0) kJ/mol. The charge transfer occurring from the ethers to atomic Cl is moderate and ranges between 0.012 e (nF = 4) to 0.188 e (nF = 0). The binding energies are linearly related to the proton affinity, to the charge transfer (CT) occurring in the molecular system and inversely proportional to the ionization potential and electron affinity (IP-EA) values. The CT and spin density data indicate substantial two-center-three-electron O···Cl interaction in CH3OCH3···Cl and CH3OCH2F···Cl systems, whereas for highly fluorinated ethers the interaction is predominantly electrostatic in nature. The formation of the complex results in a contraction of the CH bonds, especially in the gauche position. The blue shifts of the C-H stretching vibrations calculated in the partially deuterated isotopomers range between 2 and 54 cm(-1) and are correlated to the variation of the CH distances. PMID:23876015

Zeegers-Huyskens, Therese; Lily, Makroni; Sutradhar, Dipankar; Chandra, Asit K

2013-08-22

109

Synthesis of dimethyl ether and alternative fuels in the liquid phase from coal-derived synthesis gas. Task 3.2: Screen novel catalyst systems; Task 3.3:, Evaluation of the preferred catalyst system.  

National Technical Information Service (NTIS)

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 w...

R. P. Underwood

1993-01-01

110

Enhancement of dopamine sensing by layer-by-layer assembly of PVI-dmeOs and Nafion on carbon nanotubes  

Microsoft Academic Search

In this study, carbon nanotubes (CNTs) were modified to further improve their performance in electrochemical sensing of dopamine (DA) levels. After a redox polymer, poly(vinylimidazole) complexed with Os(4, 4'-dimethyl- 2, 2-bipyridine)2Cl (termed PVI-dmeOs) was electrodeposited on multi-wall CNTs (MWCNTs), Nafion and PVI-dmeOs films were successfully layer-by-layer (LBL) assembled on the hydrophilic surface of the as-prepared PVI-dmeOs\\/CNTs nanocomposites through electrostatic interactions.

Hui-Fang Cui; Yu-Han Cui; Yu-Long Sun; Kuan Zhang; Wei-De Zhang

2010-01-01

111

Di-?-acetato-bis-(dimethyl-formamide)-penta-kis-(?-N,2-dioxidobenzene-1-car-boximidato)tetra-kis-(1-ethyl-imidazole)-penta-manganese(III)-manganese(II)-diethyl ether-dimethyl-foramide-methanol-water (1/1/1/1/0.12)  

PubMed Central

The title compound [Mn6(C7H4NO3)5(CH3CO2)2(C5H8N2)4(C3H7NO)2]·(C2H5)2O·C3H7NO·CH3OH·0.12H2O, abbreviated as MnII(OAc)2[15-MCMnIII(N)shi-5](EtIm)4(DMF)2·diethyl ether·DMF·MeOH·0.12H2O (where ?OAc is acetate, MC is metallacrown, shi3? is salicylhydroximate, EtIM is n-ethylimidazole, DMF is N,N-dimethylformamide, and MeOH is methanol) contains five MnIII ions as members of the metallacrown ring and an MnII ion bound in the central cavity. The central MnII ion is seven-coordinate with a distorted face-capped trigonal–prismatic geometry. The five MnIII ions of the metallacrown ring are six-coordinate with distorted octa­hedral geometries. The configuration of the MnIII ions about the metallacrown ring follow a ???PP pattern, with P representing planar. The four 1-ethyl­imidazole ligands are bound to four different MnIII ions. A diethyl ether solvent mol­ecule was found to be disordered over two mutually exclusive sites with an occupancy ratio of 0.568?(7):0.432?(7). A methanol solvent mol­ecule was found to be disordered over two mutually exclusive sites by being hydrogen bonded either to a dimethyl­formamide solvent mol­ecule (major occupancy component) or to an O atom of the main mol­ecule (minor occupancy component). The occupancy ratio refined to 0.678?(11):0.322?(11). Associated with the minor component is a partially occupied water mol­ecule [total occupancy 0.124?(15)].

Tigyer, Benjamin R.; Zeller, Matthias; Zaleski, Curtis M.

2011-01-01

112

Stabilities of the C-H...O bonded complexes of the haloforms HCClnF3-n (n = 0-3) with dimethyl ether, oxirane, and acetone: an experimental and theoretical study.  

PubMed

Complexation enthalpies of the complexes of the haloforms HCCl(n)F(3-)(n) (n = 0-3) with dimethyl ether, oxirane, and acetone have been determined in liquid krypton and/or liquid argon using infrared spectroscopy. The same quantities were derived starting from ab initio complexation energies, calculated at the MP2=FULL/aug-cc-VTZ level, and by correcting these energies for thermodynamic and solvent contributions. The two sets of data are compared and discussed. PMID:16833298

Delanoye, Sofie N; Herrebout, Wouter A; van der Veken, Benjamin J

2005-11-01

113

Synthesis of dimethyl ether and alternative fuels in the liquid phase from coal-derived synthesis gas. Task 3.2: Screen novel catalyst systems; Task 3.3:, Evaluation of the preferred catalyst system  

Microsoft Academic Search

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

1993-01-01

114

Methanol and 2-methyl-1-propanol (isobutanol) coupling to ethers and dehydration over Nafion H: Selectivity, kinetics, and mechanism  

SciTech Connect

The dehydration of a mixture of methanol and isobutanol has been studied over the sulfonic acid Nafion H catalyst. Dehydration products consisted of dimethyl ether (DME), di-isobutyl ether (DIBE), methyl-isobutyl ether (MIBE), butenes, octenes, and traces of methyl-tertiarybutyl ether (MTBE). At low temperatures and high alcohol pressures (P [ge] 150 kPa), the dehydration product slate was dominated by ether formation with selectivity within the ethers significantly in favor of the mixed ether, MIBE. The rates of ether and butene formation as a function of alcohol pressure could be described by Langmuir-Hinshelwood kinetics in which competitive adsorption of the two alcohols on the surface -SO[sub 3]H sites was the dominant feature. The kinetics of isobutanol dehydration to isobutene were consistent with a dual-site mechanism involving the cooperative action of a free surface -SO[sub 3]H site and an adjacent adsorbed alcohol molecule. Dehydration to ethers was consistent with the reaction of two adsorbed alcohols, also by a dual-site mechanism. As a consequence, dehydration to symmetric ethers showed saturation-type kinetics as a function of alcohol pressure, while the rate of isobutene formation went through a distinct maximum. Due to the competitive adsorption of methanol and isobutanol, the mixed ether MIBE was formed at a maximum rate with an optimum ratio of partial pressures of the two alcohols. The high selectivity to MIBE was explained by stronger adsorption of isobutanol on the catalyst surface as compared to methanol. The absence of MTBE and the predominance of products such as MIBE and 2,5-dimethylhexene suggests that dehydration to give free carbenium ions that subsequently rearrange to the more stable tertiary intermediate was not occurring. It was proposed that the alcohols react with the -SO[sub 3]H groups to give oxonium ions or esters. These intermediates couple to give the product ethers or octenes. 24 refs., 13 figs., 1 tab.

Nunan, J.G.; Klier, K.; Herman, R.G. (Lehigh Univ., Bethlehem, PA (United States))

1993-02-01

115

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

116

Interface Properties between Lithium Metal and a Composite Polymer Electrolyte of PEO18Li(CF3SO2)2N-Tetraethylene Glycol Dimethyl Ether.  

PubMed

The electrochemical properties of a composite solid polymer electrolyte, consisting of poly(ethylene oxide) (PEO)-lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) and tetraethylene glycol dimethyl ether (TEGDME) was examined as a protective layer between lithium metal and a water-stable lithium ion-conducting glass ceramic of Li1+x+y(Ti,Ge)2-xAlxP3-ySiyO12 (LTAP). The lithium ion conductivity and salt diffusion coefficient of PEO18LiTFSI were dramatically enhanced by the addition of TEGDME. The water-stable lithium electrode with PEO18LiTFSI-2TEGDME, as the protective layer, exhibited a low and stable electrode resistance of 85 ?·cm2 at 60 °C, after 28 days, and low overpotentials of 0.3 V for lithium plating and 0.4 V for lithium stripping at 4.0 mA·cm-2 and 60 °C. A Li/PEO18LiTFSI-2TEGDME/LTAP/saturated LiCl aqueous solution/Pt, air cell showed excellent cyclability up to 100 cycles at 2.0 mAh·cm-2. PMID:24957059

Wang, Hui; Matsui, Masaki; Takeda, Yasuo; Yamamoto, Osamu; Im, Dongmin; Lee, Dongjoon; Imanishi, Nobuyuki

2013-01-01

117

Cannabidiol-2?,6?-dimethyl Ether as an Effective Protector of 15-Lipoxygenase-Mediated Low-Density Lipoprotein Oxidation in Vitro  

PubMed Central

15-Lipoxygenase (15-LOX) is one of the key enzymes responsible for the formation of oxidized low-density lipoprotein (ox-LDL), a major causal factor for atherosclerosis. Both enzymatic (15-LOX) and non-enzymatic (Cu2+) mechanisms have been proposed for the production of ox-LDL. We have recently reported that cannabidiol-2?,6?-dimethyl ether (CBDD) is a selective and potent inhibitor of 15-LOX-catalyzed linoleic acid oxygenation (Takeda et al., Drug Metab. Dispos., 37, 1733–1737 (2009)). In the LDL, linoleic acid is present as cholesteryl linoleate, the major fatty acid esterified to cholesterol, and is susceptible to oxidative modification by 15-LOX or Cu2+. In this investigation, we examined the efficacy of CBDD on i) 15-LOX-catalyzed oxygenation of cholesteryl linoleate, and ii) ox-LDL formation catalyzed by 15-LOX versus Cu2+-mediated non-enzymatic generation of this important mediator. The results obtained demonstrate that CBDD is a potent and selective inhibitor of ox-LDL formation generated by the 15-LOX pathway. These studies establish CBDD as both an important experimental tool for characterizing 15-LOX-mediated ox-LDL formation, and as a potentially useful therapeutic agent for treatment of atherosclerosis.

Takeda, Shuso; Hirayama, Akari; Urata, Shino; Mano, Nobutaka; Fukagawa, Keiko; Imamura, Midori; Irii, Ayumi; Kitajima, Satomi; Masuyama, Tomoko; Nomiyama, Mai; Tatei, Sachiko; Tomita, Saari; Kudo, Taichi; Noguchi, Momoko; Yamaguchi, Yasuhiro; Okamoto, Yoshiko; Amamoto, Toshiaki; Fukunishi, Yoshifumi; Watanabe, Kazuhito; Omiecinski, Curtis John; Aramaki, Hironori

2014-01-01

118

Interface Properties between Lithium Metal and a Composite Polymer Electrolyte of PEO18Li(CF3SO2)2N-Tetraethylene Glycol Dimethyl Ether  

PubMed Central

The electrochemical properties of a composite solid polymer electrolyte, consisting of poly(ethylene oxide) (PEO)-lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) and tetraethylene glycol dimethyl ether (TEGDME) was examined as a protective layer between lithium metal and a water-stable lithium ion-conducting glass ceramic of Li1+x+y(Ti,Ge)2?xAlxP3?ySiyO12 (LTAP). The lithium ion conductivity and salt diffusion coefficient of PEO18LiTFSI were dramatically enhanced by the addition of TEGDME. The water-stable lithium electrode with PEO18LiTFSI-2TEGDME, as the protective layer, exhibited a low and stable electrode resistance of 85 ?·cm2 at 60 °C, after 28 days, and low overpotentials of 0.3 V for lithium plating and 0.4 V for lithium stripping at 4.0 mA·cm?2 and 60 °C. A Li/PEO18LiTFSI-2TEGDME/LTAP/saturated LiCl aqueous solution/Pt, air cell showed excellent cyclability up to 100 cycles at 2.0 mAh·cm?2.

Wang, Hui; Matsui, Masaki; Takeda, Yasuo; Yamamoto, Osamu; Im, Dongmin; Lee, Dongjoon; Imanishi, Nobuyuki

2013-01-01

119

Dimethyl ether in its ground state, v = 0, and lowest two torsionally excited states, v11 = 1 and v15 = 1, in the high-mass star-forming region G327.3-0.6  

NASA Astrophysics Data System (ADS)

Context. One of the big questions in astrochemistry is whether complex organic molecules are formed in the gas phase after evaporation of the icy mantles of interstellar dust grains or at intermediate temperatures within these icy mantles. Dimethyl ether (CH3OCH3) is one of these species that may form through either of these mechanisms, but it is yet unclear which is dominant. Aims: The goal of this paper is to determine the respective importance of solid state vs. gas phase reactions for the formation of dimethyl ether. This is done by a detailed analysis of the excitation properties of the ground state and the torsionally excited states, ?11 = 1 and ?15 = 1, toward the high-mass star-forming region G327.3-0.6. Methods: With the Atacama Pathfinder EXperiment 12 m submillimeter telescope, we performed a spectral line survey toward G327.3-0.6 around 1.3, 1.0, and 0.9 mm as well as at 0.43 and 0.37 mm. The observed CH3OCH3 spectrum is modeled assuming local thermal equilibrium. Results: CH3OCH3 has been detected in the ground state, ?= 0, and in the torsionally excited states ?11 = 1 and ?15 = 1, for which lines have been detected here for the first time. The emission is modeled with an isothermal source structure as well as with a non-uniform spherical structure. In the isothermal case two components at 80 and 100 K are needed to reproduce the dimethyl ether emission, whereas an abundance jump at 85 K or a model with two abundance jumps at 70 and 100 K fit the emission equally well for the non-uniform source model. The emission from the torsionally excited states, ?11 = 1 and ?15 = 1, is very well fit by the same model as the ground state. Conclusions: For non-uniform source models one abundance jump for dimethyl ether is sufficient to fit the emission, but two components are needed for the isothermal models. This suggests that dimethyl ether is present in an extended region of the envelope and traces a non-uniform density and temperature structure. Both types of models furthermore suggest that most dimethyl ether is present in gas that is warmer than 100 K, but a smaller fraction of 5%-28% is present at temperatures between 70 and 100 K. The dimethyl ether present in this cooler gas is likely formed in the solid state, while gas phase formation probably is dominant above 100 K. Finally, the ?11 = 1 and ?15 = 1 torsionally excited states are easily excited under the density and temperature conditions in G327.3-0.6 and will thus very likely be detectable in other hot cores as well. Appendix A is available in electronic form at http://www.aanda.org

Bisschop, S. E.; Schilke, P.; Wyrowski, F.; Belloche, A.; Brinch, C.; Endres, C. P.; Güsten, R.; Hafok, H.; Heyminck, S.; Jørgensen, J. K.; Müller, H. S. P.; Menten, K. M.; Rolffs, R.; Schlemmer, S.

2013-04-01

120

KINETIC UNDERSTANDING OF THE SYNGAS-TO-DME REACTION SYSTEM AND ITS IMPLICATIONS TO PROCESS AND ECONOMICS  

SciTech Connect

In a single-step synthesis gas-to-dimethyl ether process, synthesis gas (or syngas, a mixture of H{sub 2} and CO) is converted into dimethyl ether (DME) in a single reactor. The three reactions involved in this process, methanol synthesis, methanol dehydration and water gas shift, form an interesting reaction network. The interplay among these three reactions results in excellent syngas conversion or reactor productivity. A fundamental understanding of this interplay helps to explain many experimental and simulation observations, to identify optimal reaction conditions, and to provide guidelines for process development. The higher syngas conversion or reactor productivity in the syngas-to-DME reaction system, compared to that in the syngas-to-methanol reaction system, is referred to as chemical synergy. This synergy exhibits a strong dependence on the composition of the reactor feed. To demonstrate the extent of this dependence, simulations with adjusted activity for each reaction were performed to reveal the relative rate of each reaction. The results show that the water gas shift reaction is the most rapid, being practically controlled by the equilibrium. Both methanol synthesis and methanol dehydration reactions are kinetically controlled. The kinetics of the dehydration reactions is greater than that of the methanol synthesis reaction in the CO-rich regime. However, the rates of these two reactions come closer as the H{sub 2} concentration in the reactor feed increases. The role of the dehydration reaction is to remove the equilibrium barrier for the methanol synthesis reaction. The role of the water gas shift reaction is more complex; it helps the kinetics of methanol dehydration by keeping the water concentration low, which in turn enhances methanol synthesis. It also readjusts the H{sub 2}:CO ratio in the reactor as the reactions proceed. In the CO-rich regime, the water gas shift reaction supplements the limiting reactant, H{sub 2}, by reacting water with CO. This enhances both the kinetics and thermodynamic driving force of the methanol synthesis reaction. In the H{sub 2}-rich regime, water gas shift consumes the limiting reactant, CO, which harms both the kinetics and thermodynamics of methanol synthesis. An understanding of these complex roles of the methanol dehydration and water gas shift reactions and of their dependence on the syngas composition explains why the synergy is high in the CO-rich regime, but decreases with increasing H{sub 2} or CO{sub 2} content in the reactor feed. The methanol equivalent productivity of the syngas-to-DME reactor is also a strong function of the reactor feed. A mathematical approach was developed to understand this dependence. The approach divides a power law type of rate equation into two terms, the kinetic term (the rate of the forward reaction) and the thermodynamics or driving force term (1- approach to equilibrium). The equations for the best feed composition for each term were derived. The approach was developed for the single reaction system, and then extended to the syngas-to-DME reaction system. The equations provide insights into why and how the methanol synthesis in the syngasto-DME system depends on the other two reactions. They can also be used to calculate the best feed composition for a given conversion. The analysis shows that for typical commercial syngas conversion, the optimal H{sub 2}:CO ratio for the LPDME{trademark} reactor is around 1-to-1, in good agreement with the results from the simulation. While the 1-to-1 feed provides a good foundation for some process configurations, it does not match the composition of natural gas-derived syngas, which typically has a H{sub 2}:CO ratio of 2:1 or greater. The process would also produce one CO{sub 2} molecule for every DME product, both a materials utilization and an environmental problem. However, recycling CO{sub 2} to the syngas generation unit can solve all of these problems. Integration schemes with different syngas generation technologies (dry reforming, steam methane reforming and partial oxidation) were

Xiang-Dong Peng

2002-12-01

121

Effects of ZrO 2 on the Performance of CuO-ZnO-Al 2O 3\\/HZSM-5 Catalyst for Dimethyl Ether Synthesis from CO 2 Hydrogenation  

Microsoft Academic Search

A series of composite catalysts were prepared by the wet mixing method, and the mass ratio of CuO-ZnO-Al2O3-ZrO2 component to HZSM-5 zeolite (molar ratio of SiO2 to Al2O3 being 25) was 2:1. The CuO-ZnO-Al2O3-ZrO2 (CuO\\/ZnO\\/Al2O3=3\\/6\\/1 by weight) component was prepared by a modified ‘two-step’ co-precipitation method. The effects of ZrO2 on the performance of CuO-ZnO-Al2O3\\/HZSM-5 catalyst for dimethyl ether synthesis

Yanqiao Zhao; Jixiang Chen; Jiyan Zhang

2007-01-01

122

Ozonolysis of alkenes and reactions of polyfunctional compounds. XXXI. Ozonolysis of cyclic olefins in solvents of ether type for the case of dimethyl endo,cis-bicyclo(2. 2. 1)hept-5-ene-2,3-dicarboxylate  

SciTech Connect

It was found that the product from intramolecular reaction of a zwitterion with the methoxycarbonyl group is formed during the ozonization of dimethyl endo,cis-bicyclo(2.2.1)hept-5-ene-2,3-dicarboxylate in diethyl ether. Its structure was established by x-ray crystallographic investigation as endo,cis-4-methoxy-5-methoxycarbonyl-6-formyl-1,4-epoxy-2,3-dioxacyclopenta(2,3-d)cyclohexane. The PMR spectra were obtained on a Tesla BS-567 spectrometer at 100 MHz with deuterochloroform as solvent. The /sup 13/C NMR spectra were recorded on a JEOL Fx-900 instrument at 22.5 MHz with deuterochloroform as solvent.

Odinokov, V.N.; Kukovinets, O.S.; Botsman, L.P.; Khalilov, L.M.; Tolstikov, G.A.; Kosnikov, A. Yu.; Lindeman, S.V.; Struchkov, Yu.T.

1987-10-10

123

A velocity map imaging photoelectron spectrometer for the study of ultrafine aerosols with a table-top VUV laser and Na-doping for particle sizing applied to dimethyl ether condensation  

NASA Astrophysics Data System (ADS)

We present a new experimental configuration for the study of size-dependent, angle-resolved photoelectron and photoion spectra of weakly bound ultrafine aerosol particles targeted at particle sizes below ~20 nm. It combines single photon ionization by a tunable, table-top vacuum ultraviolet laser at energies up to 18 eV with velocity map imaging detection and independent size determination of the aerosol particles using the Na-doping method. As an example, the size-dependence of the valence photoelectron spectrum of dimethyl ether clusters and ultrafine aerosols is investigated. Up to a mean particle diameter of ~3-4 nm, the first ionization energy (value at band maximum) decreases systematically (up to ~1 eV) and the corresponding band broadens systematically (up to a factor of ~3) with increasing aggregate size. Plateau values for band positions and bandwidths are reached beyond a diameter of ~3-4 nm. Experimental evidence for the dominance of the fast intermolecular proton transfer over monomer fragmentation reactions upon ionization is presented via photoion imaging.

Yoder, Bruce L.; West, Adam H. C.; Schläppi, Bernhard; Chasovskikh, Egor; Signorell, Ruth

2013-01-01

124

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

125

Emissions from Ethers and Organic Carbonate Fuel Additives: A Review  

Microsoft Academic Search

This paper is a review of the available literature on the main features of 11 of the most widely adopted oxygenated additives\\u000a to base gasoline and diesel, focusing particularly on the emissions from the oxygenates considered as additives. The oxygenated\\u000a additives studied are methyl tert-butyl ether, ethyl tertiary butyl ether, tert-amyl ethyl ether, tertiary amyl methyl ether, isopropyl ether, dimethyl

Alessia Arteconi; Alessandro Mazzarini; Giovanni Di Nicola

126

Polyarylene Ethers with Improved Properties  

NASA Technical Reports Server (NTRS)

This invention relates to novel polyarylene ethers which possess the combination of high strength, toughness, and high use temperature with ease of extrusion and formation into complex objects. These polyarylene ethers are suitable for use in adhesives, coatings, films, membranes, and composite matrices. The polyarylene ethers of this invention are the polycondensation products from the reaction of either 1,3-bis (4-chloro or fluorobenzoyl) benzene with any one of the following bisphenolic compounds: bis (3-hydroxyphenyl) methane; bis (4-hydroxyphenyl) methane; 1,1-dimethyl-bis (4-hydroxyphenyl)methane, or 9,9-bis (4-hydroxyphenyl) fluorene. Random and block copolymers are also comprehended.

Hergenrother, P. M. (inventor); Jensen, B. J. (inventor); Havens, S. J. (inventor)

1986-01-01

127

Dimethyl Fumarate  

MedlinePLUS

... to treat psoriasis (a skin disease in which red, scaly patches form on some areas of the ... or any of the ingredients in dimethyl fumarate capsules. Ask your pharmacist or check the manufacturer's patient ...

128

'3Dme--a look inside' creative studio.  

PubMed

3Dme are creative 3D digital story-tellers with a passion for making complex health and medical information comprehensible. They have an enviable ability to understand a broad range of health and medical topics and present them in an accurate and visually engaging manner. '3Dme - A Look Inside' is a privately owned 3D visualisation and multimedia company established by Luke and Sonya Brannelly in 2006. 3Dme are passionate about creating beautiful, scientifically accurate, relevant, high definition, full 3D visualisation presentations to take a look inside the human body to communicate a health or medical education message via engaging, creative digital story-telling. 3Dme's primary objective is to 'improve global health and education outcomes'. Winning a number of local and international awards for their work, they are well on their way to achieving this. 3Dme's vision is simply to use their scientific and artistic skills along with the reach of the internet and digital technology, to captivate, engage and inspire everyone from primary school students, teachers and parents, through to university undergraduates, academics and medical specialists, to improve their understanding of complex health and medical topics. The digital output of their 3D presentations is suitable for a variety of delivery platforms and includes e-learning modules, blended learning, interactive learning modules and Apps. 3Dme has made, and continues to make, significant investments in technology based hardware and software, boasting one of the largest in-house, fully equipped animation render farms in Queensland, Australia. PMID:22397485

Brannelly, Sonya

2012-03-01

129

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

130

Collision-induced dissociation studies of protonated ether--(H2O)n (n = 1-3) clusters.  

PubMed

We have studied the protonated ether-(H2O)n (n = 1-3) complexes containing tetrahydrofuran, dimethyl, diethyl, dibutyl, and butylmethyl ethers using a flowing afterglow triple-quadrupole mass spectrometer. Collision-induced dissociation, CID, of all clusters with n = 1, 2 shows sequential water loss. The n = 3 cluster of dimethyl ether shows sequential water loss, while all other ether clusters display selective product formation. The CID spectra are interpreted based on known energetics, and theoretical studies of the dimethyl and diethyl ether systems. PMID:16421874

Goebbert, Daniel J; Chen, Hao; Wenthold, Paul G

2006-02-01

131

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

132

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

133

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

134

Synthesis and characterization of sulfonated poly(ether ether ketone) for proton exchange membranes  

Microsoft Academic Search

Series of sulfonated poly(ether ether ketone)s (SPEEKs) were prepared by sulfonation of commercial Victrex® and Gatone® PEEK for a comparative study of proton exchange membranes (PEM) intended for fuel cell applications. The degree of sulfonation (DS) of the sulfonated PEEK was determined from deuterated dimethyl sulfoxide (DMSO-d6) solution of the purified polymers using 1H NMR methods. The second method using

Peixiang Xing; Gilles P Robertson; Michael D Guiver; Serguei D Mikhailenko; Keping Wang; Serge Kaliaguine

2004-01-01

135

Conductivity and viscosity studies of dimethyl sulfoxide (DMSO)-based electrolyte solutions at 25 C  

NASA Astrophysics Data System (ADS)

The specific conductivities and viscosities of lithium perchlorate at four different concentrations in dimethyl sulfoxide (DMSO)-based, binary mixed solvents are reported at 25 C. The co-solvents are tetrahydrofuran (THF), 1,2-dimethoxyethane (DME) and 1,3-dioxolane (DOL). The change in viscosity with solvent composition in all three mixed-solvent systems without electrolyte indicates the occurrence of structural disruption. The observed increase in viscosity with increase in LiClO4 concentration suggests an increasing compactness of the structure. A 2 M LiClO4 solution shows maximum conductivity at 20 vol.% DMSO in DMSO + DOL and at 40 vol.% DMSO in DMSO + THF mixtures. By contrast, a 1.5 M LiClO4 solution has maximum conductivity at 40 vol.% DMSO in DMSO + DME mixtures. Preferential solvation of LiClO4 by DMSO occurs in the respective mixtures with THF, DME and DOL.

Kumar, T. Prem; Prabhu, P. V. S. S.; Srivastava, A. K.; Kumar, U. Bejoy; Ranganathan, R.; Gangadharan, R.

1994-07-01

136

14 CFR 171.321 - DME and marker beacon performance requirements.  

...Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) NAVIGATIONAL FACILITIES NON-FEDERAL NAVIGATION FACILITIES Microwave Landing System (MLS) § 171.321 DME and marker beacon performance requirements....

2014-01-01

137

In situ Raman spectroscopy of lithium electrode surface in ambient temperature lithium secondary battery. Final report.  

National Technical Information Service (NTIS)

Raman spectroscopy was used to characterize surface layers on lithium electrodes in different solvents such as propylene carbonate (PC), dimethyl carbonate (DMC), diethyl carbonate (DEC), and polyethylene glycol 400 dimethyl ether (PEG400DME). Both DMC an...

H. Tachikawa

1992-01-01

138

Characterization of Lithium Electrode Surface in Lithium Secondary Batteries by In situ Raman Spectroscopic Methods.  

National Technical Information Service (NTIS)

Surface layers on lithium electrodes formed in several solvents including dimethyl carbonate (DMC), diethyl carbonate (DEC), polyethylene glycol 400 dimethyl ether (PEG400DME), and propylene carbonate (PC) have been studied by Raman spectroscopy. Both DMC...

H. Tachikawa

1993-01-01

139

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

Federal Register 2010, 2011, 2012, 2013

...AccessTel, Inc., American Asset Management Corp., DME Interactive Holdings, Inc., DocuPort, Inc., and iCarbon Corp...and accurate information concerning the securities of DME Interactive Holdings, Inc. because it has not filed any periodic...

2011-03-11

140

High octane ethers from synthesis gas-derived alcohol  

SciTech Connect

The objective of the proposed research is to synthesize high octane ethers directly from coal-derived synthesis gas via alcohol mixtures that are rich in methanol and isobutanol. The overall scheme involves gasification of coal, purification and shifting of the synthesis gas, higher alcohol synthesis, and direct synthesis of ethers. Commercial acid and superacid resin catalysts were obtained and tested under one set of conditions to compare the activities and selectivities for forming the unsymmetric methylisobutylether (MIBE) by coupling methanol with isobutanol. It was found that both Nafion-H microsaddles and Amberlyst-15 resins are active for this synthesis reaction. While and the Nafion-H catalyst does form the MIBE product fairly selectively under the reaction conditions utilized, the Amberlyst-15 catalyst formed dimethylether (DME) as the major product. In addition, significantly larger quantities of the C{sub 4} hydrocarbon products were observed over the Amberlyst-15 catalyst at 123{degree}C and 13.6 atm. It has been demonstrated that methyltertiarybutylether (MTBE) MIBE, DME and diisobutylether (DIBE) are separated and quantitatively determined by using the proper analytical conditions. In order to gain insight into the role of superacidity in promoting the selective coupling of the alcohols to form the unsymmetric ether, the strengths of the acid sites on the catalysts are being probed by thermometric titrations in non-aqueous solutions. 18 refs., 20 figs., 4 tabs.

Klier, K.; Herman, R.G.; Bastian, R.D.; DeTavernier, S. (Lehigh Univ., Bethlehem, PA (USA). Dept. of Chemistry Lehigh Univ., Bethlehem, PA (USA). Zettlemoyer Center for Surface Studies)

1991-01-01

141

Nuclear Magnetic Resonance Evidence for the Diborohydride Ion in Polyethylene Glycol Ethers  

Microsoft Academic Search

THE complex formed by absorption of diborane in solutions of borohydride ion in polyethylene glycol ethers is of considerable interest because it probably contains the simplest B-H-B bridge system known. Brown et al.1 reported that solutions of sodium or lithium borohydride in diethylene glycol dimethyl ether absorb a half molar equivalent of diborane. On this evidence it was suggested that

B. J. Duke

1964-01-01

142

DME-Derived Positions Compared with MLS- and ILS-Derived Positions.  

National Technical Information Service (NTIS)

From Distance Measurement Equipment (DME) data recorded during Microwave Landing System (MLS) flight trials, the positions of the aircraft was determined by postprocessing and compared with the MLS and Instrument Landing System (ILS) derived positions. An...

P. J. Hoogeboom

1990-01-01

143

DME-Derived Positions Compared with MLS- and ILS-Derived Positions.  

National Technical Information Service (NTIS)

From recorded Distance Measurement Equipment (DME) data during Microwave Landing System (MLS) flight trials performed at London Gatwick Airport (April 21 - 26, 1989) using the NLR Fairchild Metro II Laboratory Aircraft, the position of the aircraft was de...

P. J. Hoogeboom

1990-01-01

144

Derivation of Groundspeed Information from Airborne Distance Measuring Equipment (DME) Interrogators.  

National Technical Information Service (NTIS)

Laboratory and flight tests were conducted to investigate the derivation of aircraft groundspeed from the range rate pulse information obtained from ARINC 568 distance measuring equipment (DME) interrogators. Initial tests determined the limitation of the...

J. Gallagher W. Lynn R. H. Pursel

1977-01-01

145

Cation–ether complexes in the gas phase: thermodynamic insight into molecular recognition  

Microsoft Academic Search

Trends in the bond dissociation energies for the binding of the alkali metal cations, Li+, Na+, K+, Rb+, and Cs+, to a series of ethers, 1–4 dimethyl ethers, 1 and 2 dimethoxy ethanes, and the crown ethers, 12c4, 15c5, and 18c6, are discussed. The bond energies have been determined in previous studies by analysis of the thresholds for collision-induced dissociation

P. B. Armentrout

1999-01-01

146

Molecular Dynamic Simulation of 1,2-Dimethoxyethane(DME)/Water System: Static and Dynamic Properties.  

NASA Astrophysics Data System (ADS)

A high-level quantum chemistry based force field was used to perform a series of molecular dynamic (MD) simulations of DME/water mixtures in liquid phase. The structural and dynamic properties of the system were investigated for seven different compositions (XDME=0.004, 0.04, 0.10, 0.18, 0.42, 0.72, 0.90) at three temperatures (T=318K, 368K, 450K). It was found that the tgt conformer of DME is the most probable one in water rich compositions. The analysis of radial distribution functions showed that the reason of this stabilization of tgt is partially because the oxygen positioning in tgt DME easily fits into the water bulk structure. However, at the same time it does not fit perfectly in that structure. Also, it was found that with increasing DME concentration the ordering of water increases. The analysis of self-diffusion coefficients showed that two kinds of water molecules ('free' and 'bounded' with DME) exist in the systems with low concentration of DME. Characteristic times of each kind of water molecules were determined. All properties were investigated as a function of temperature.

Bedrov, Dmitry; Borodin, Oleg; Smith, Grant

1998-03-01

147

Cation-ether complexes in the gas phase: Bond dissociation energies of Na{sup +}(dimethyl ether){sub x}, x = 1-4; Na{sup +}(1,2-dimethoxyethane){sub x}, x = 1 and 2; and Na{sup +}(12-crown-4)  

SciTech Connect

Bond dissociation energies of Na{sup +}[O(CH{sub 3}){sub 2}]{sub x}, x = 1-4; Na{sup +}[(CH{sub 2}OCH{sub 3}){sub 2}]{sub x}, x = 1 and 2; and Na{sup +}[c-(C{sub 2}H{sub 4}O){sub 4}] are reported. The bond dissociation energies are determined experimentally by analysis of the thresholds for collision-induced dissociation of the cation-ether complexes by xenon measured using guided ion beam mass spectrometry. In all cases, the primary and lowest energy dissociation channel observed experimentally is endothermic loss of one ligand molecule. The cross section thresholds are interpreted to yield 0 and 298 K bond dissociation energies after accounting for the effects of multiple ion-molecule collisions, internal energy of the complexes, and unimolecular decay rates. Trends in the bond dissociation energies determined by experiment and recent theoretical ab initio calculations are in good agreement. Our best experimental values, which have an average uncertainty of {+-}7 kJ/mol, are lower than the theoretical values by 7 {+-} 5 kJ/mol per metal-oxygen interaction. These values are compared with bond dissociation energies for the comparable lithium cation-ether complexes. This comparison reveals the thermodynamic consequences of ligand-ligand repulsion. 51 refs., 5 figs., 4 tabs.

More, M.B.; Armentrout, P.B. [Univ. of Utah, Salt Lake City, UT (United States)] [Univ. of Utah, Salt Lake City, UT (United States); Ray, D. [Pacific Northwest National Lab., Richland, WA (United States)] [Pacific Northwest National Lab., Richland, WA (United States)

1997-01-30

148

Imprinting of the MEA Polycomb gene is controlled by antagonism between MET1 methyltransferase and DME glycosylase.  

PubMed

The MEA Polycomb gene is imprinted in the Arabidopsis endosperm. DME DNA glycosylase activates maternal MEA allele expression in the central cell of the female gametophyte, the progenitor of the endosperm. Maternal mutant dme or mea alleles result in seed abortion. We identified mutations that suppress dme seed abortion and found that they reside in the MET1 methyltransferase gene, which maintains cytosine methylation. Seeds with maternal dme and met1 alleles survive, indicating that suppression occurs in the female gametophyte. Suppression requires a maternal wild-type MEA allele, suggesting that MET1 functions upstream of, or at, MEA. DME activates whereas MET1 suppresses maternal MEA::GFP allele expression in the central cell. MET1 is required for DNA methylation of three regions in the MEA promoter in seeds. Our data suggest that imprinting is controlled in the female gametophyte by antagonism between the two DNA-modifying enzymes, MET1 methyltransferase and DME DNA glycosylase. PMID:14667411

Xiao, Wenyan; Gehring, Mary; Choi, Yeonhee; Margossian, Linda; Pu, Hong; Harada, John J; Goldberg, Robert B; Pennell, Roger I; Fischer, Robert L

2003-12-01

149

The Millimeter and Submillimeter-Wave Spectrum of the trans-trans Conformer of Diethyl Ether (C2H5OC2H5)  

Microsoft Academic Search

Since dimethyl ether is found to have a high abundance in hot cores, it is reasonable to search among such sources for detectable abundances of the more complex analogs ethyl methyl ether (C2H5OCH3) and diethyl ether (C2H5OC2H5). Indeed, preliminary detections of both complex ethers have been reported. Definitive interstellar searches do require laboratory spectra, however, but for many years only

Ivan Medvedev; Manfred Winnewisser; Frank C. De Lucia; Eric Herbst; Enyi Yi; Lai Peng Leong; Ryan P. A. Bettens; Ewa Bialkowska-Jaworska; Oleksandr Desyatnyk; Lech Pszczólkowski; Zbigniew Kisiel

2003-01-01

150

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.

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

2013-01-01

151

First Perfluoro Crown Ethers.  

National Technical Information Service (NTIS)

The first perfluoro crown ethers, perfluoro 18-crown-6. perfluoro 15-crown-5, and perfluoro 12-crown-4, have been prepared by carefully controlled elemental fluorination; although they are weaker bases than their parent compounds, perfluoro crown ethers a...

W. H. Lin W. I. Bailey R. J. Lagow

1985-01-01

152

Performance of long straw tubes using dimethyl ether  

Microsoft Academic Search

A cylindrical tracking detector with an inner radius of one meter employing straw tubes is being envisaged for the FINUDA experiment aimed at hyper-nuclear physics at DA?NE, the Frascati ?-factory. A prototype using several 10 mm and 20 mm diameter, two meter long aluminized mylar straws has been assembled and tested with a one GeV\\/c pion beam. While operating with

L. Benussi; M. Bertani; S. Bianco; F. L Fabbri; P. Gianotti; M. Giardoni; C. Guaraldo; A. Lanaro; V. Lucherini; A. Mecozzi; L. Passamonti; V. Russo; S. Sarwar

1995-01-01

153

Liquid phase methanol and dimethyl ether synthesis from syngas  

Microsoft Academic Search

The Liquid Phase Methanol Synthesis (LPMeOHTM) process has been investigated in our laboratories since 1982The reaction chemistry of liquid phase methanol synthesis over commercial Cu\\/ZnO\\/Al2O3 catalysts, established for diverse feed gas conditions including H2-rich, CO-rich, CO2-rich, and CO-free environments, is predominantly based on the CO2 hydrogenation reaction and the forward water-gas shift reactionImportant aspects of the liquid phase methanol synthesis

Sunggyu Lee; Abhay Sardesai

2005-01-01

154

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

155

?-Pyrone derivatives, kojic acid methyl ethers from a marine-derived fungus altenaria sp  

Microsoft Academic Search

Kojic acid dimethyl ether (1), and the known kojic acid monomethyl ether (2), kojic acid (3) and phomaligol A (4) have been isolated from the organic extract of the broth of the marine-derived fungusAltenaria sp. collected from the surface of the marine green algaUlva pertusa. The structures were assigned on the basis of comprehensive spectroscopic analyses. Each isolate was tested

Xifeng Li; Jee Hean Jeong; Kang Tae Lee; Jung Rae Rho; Hong Dae Choi; Jung Sook Kang; Byeng Wha Son

2003-01-01

156

Ether (or Aether)  

Microsoft Academic Search

A transparent, weightless medium which was imagined by nineteenth-century physicists to fill all space, and to provide the medium through which electromagnetic waves could propagate. Conventional physical ideas of the time did not admit of waves that could travel through `nothingness'. The concept of the ether came to be associated with the idea of absolute space, the ether providing a

P. Murdin

2000-01-01

157

Salvinorin B meth-oxy-methyl ether  

PubMed Central

The title compound [MOM-SalB; systematic name: methyl (2S,4aR,6aR,7R,9S,10aS,10bR)-2-(3-fur­yl)-9-meth­oxy­meth­oxy-6a,10b-dimethyl-4,10-dioxo-2,4a,5,6,7,8,9,10a-octa­hydro-1H-benzo[f]isochromene-7-carboxyl­ate], C23H30O8, is a deriv­ative of the ?-opioid salvinorin A with enhanced potency, selectivity, and duration of action. Superimposition of their crystal structures reveals, surprisingly, that the terminal C and O atoms of the MOM group overlap with the corresponding atoms in salvinorin A, which are separated by an additional bond. This counter-intuitive isosterism is possible because the MOM ether adopts the ‘classic anomeric’ conformation (gauche–gauche), tracing a helix around the planar acetate of salvinorin A. This overlap is not seen in the recently reported structure of the tetra­hydro­pyranyl ether, which is less potent. The classic anomeric conformation is strongly favoured in alk­oxy­methyl ethers, but not in substituted acetals, which may contribute to their reduced potency. This structure may prove useful in evaluating models of the activated ?-opioid receptor.

Munro, Thomas A.; Ho, Douglas M.; Cohen, Bruce M.

2012-01-01

158

Salvinorin B meth-oxy-methyl ether.  

PubMed

The title compound [MOM-SalB; systematic name: methyl (2S,4aR,6aR,7R,9S,10aS,10bR)-2-(3-fur-yl)-9-meth-oxy-meth-oxy-6a,10b-dimethyl-4,10-dioxo-2,4a,5,6,7,8,9,10a-octa-hydro-1H-benzo[f]isochromene-7-carboxyl-ate], C(23)H(30)O(8), is a deriv-ative of the ?-opioid salvinorin A with enhanced potency, selectivity, and duration of action. Superimposition of their crystal structures reveals, surprisingly, that the terminal C and O atoms of the MOM group overlap with the corresponding atoms in salvinorin A, which are separated by an additional bond. This counter-intuitive isosterism is possible because the MOM ether adopts the 'classic anomeric' conformation (gauche-gauche), tracing a helix around the planar acetate of salvinorin A. This overlap is not seen in the recently reported structure of the tetra-hydro-pyranyl ether, which is less potent. The classic anomeric conformation is strongly favoured in alk-oxy-methyl ethers, but not in substituted acetals, which may contribute to their reduced potency. This structure may prove useful in evaluating models of the activated ?-opioid receptor. PMID:23284529

Munro, Thomas A; Ho, Douglas M; Cohen, Bruce M

2012-11-01

159

Oral Minocycline for the Treatment of Diabetic Macular Edema (DME): Results of a Phase I/II Clinical Study  

PubMed Central

Purpose. Inflammation contributes significantly to the pathogenesis of diabetic macular edema (DME). In particular, retinal microglia demonstrate increased activation and aggregation in areas of DME. Study authors investigated the safety and potential efficacy of oral minocycline, a drug capable of inhibiting microglial activation, in the treatment of DME. Methods. A single-center, prospective, open-label phase I/II clinical trial enrolled five participants with fovea-involving DME who received oral minocycline 100 mg twice daily for 6 months. Main outcome measurements included best-corrected visual acuity (BCVA), central retinal subfield thickness (CST), and central macular volume using spectral domain optical coherence tomography (SD-OCT) and late leakage on fluorescein angiography (FA). Results. Findings indicated that the study drug was well tolerated and not associated with significant safety issues. In study eyes, mean BCVA improved continuously from baseline at 1, 2, 4, and 6 months by +1.0, +4.0, +4.0, and +5.8 letters, respectively, while mean retinal thickness (CST) on OCT decreased by ?2.9%, ?5.7%, ?13.9, and ?8.1% for the same time points. At month 6, mean area of late leakage on FA decreased by ?34.4% in study eyes. Mean changes in contralateral fellow eyes also demonstrated similar trends. Improvements in outcome measures were not correlated with concurrent changes in systemic factors. Conclusions. In this pilot proof-of-concept study of DME, minocycline as primary treatment was associated with improved visual function, central macular edema, and vascular leakage, comparing favorably with historical controls from previous studies. Microglial inhibition with oral minocycline may be a promising therapeutic strategy targeting the inflammatory etiology of DME. (ClinicalTrials.gov number, NCT01120899.)

Cukras, Catherine A.; Petrou, Philip; Chew, Emily Y.; Meyerle, Catherine B.; Wong, Wai T.

2012-01-01

160

High octane ethers from synthesis gas-derived alcohols  

SciTech Connect

The temperature dependence of ether synthesis, particularly unsymmetric methylisobutylether (MIBE), was carried out over the Nafion-H microsaddles (MS) catalyst. The principal product formed under the rather severe reaction conditions of 1100 psig pressure and temperatures in the range of 123--157{degree}C was the expected MIBE formed directly by coupling the methanol/isobutanol reactants. In addition, significantly larger quantities of the dimethylether (DME) and hydrocarbon products were observed than were obtained under milder reaction conditions. Deactivation of the Nafion-H MS catalyst was determined by periodically testing the catalyst under a given set of reaction conditions for the synthesis of MIBE and MTBE from methanol/isobutanol = 2/1, i.e. 123{degree}C, 1100 psig, and total GHSV = 248 mol/kg cat/hr. After carrying out various tests over a period of 2420 hr, with intermittant periods of standing under nitrogen at ambient conditions, the yields of MIBE and MTBE had decreased by 25% and 41%, respectively. In order to gain insight into the role of the surface acidity in promoting the selective coupling of the alcohols to form the unsymmetric ether, the strengths of the acid sites on the catalysts are still being probed by calorimetric titrations in non-aqueous solutions. 11 refs., 13 figs., 9 tabs.

Klier, K.; Herman, R.G.; DeTavernier, S.; Johannson, M.; Kieke, M.; Bastian, R.D.

1991-07-01

161

Molecular Structure of Isopropyl ether  

NSDL National Science Digital Library

Diisopropyl ether has been used an extraction agent and as a solvent in paint thinners and stain removers. It has also been considered for use as an additive to raise the octane rating of gasoline. It is released into the environment through various waste streams associated with its laboratory use and the use and manufacture of removers. Diisopropyl ether is considered mildly toxic. Short term exposures produce anesthetic effects similar to ethyl ether and irritate the eyes, the skin, and the respiratory tract. Diisopropyl ether has been found many groundwater and surface water supplies. Many ethers are known to resist biodegradation and studies suggest that diisopropyl ether is resistant as well.

2002-10-01

162

The neuropeptide FF analogue, 1DME, enhances in vivo met-enkephalin release from the rat spinal cord  

Microsoft Academic Search

Behavioural studies have suggested that endogenous opioids mediate the antinociceptive action of neuropeptide FF (FLFQPQRF–NH2) at the spinal level in the rat. This hypothesis was directly assessed by investigating the effects of a NPFF analogue, 1DMe ([D-Tyr1,(NMe)Phe3]NPFF), on the spinal outflow of met-enkephalin-like material (MELM) in halothane-anaesthetised rats. Intrathecal infusion (0.1 ml\\/min) of 1DMe (0.1 ?M–0.1 mM, for 45 min)

S Ballet; A Mauborgne; C Gouardères; A. S Bourgoin; J-M Zajac; M Hamon; F Cesselin

1999-01-01

163

Viscoelastic characterization of soft tissues by Dynamic Micro-Elastography (DME) in the frequency range of 300–1500 Hz  

Microsoft Academic Search

Mechanical characterization of living tissues and organs are of interest because information on their viscoelastic properties in the presence of diseases can affect therapy planning. This article proposes the Dynamic Micro-Elastography (DME) method to characterize elasticity and viscosity parameters from the acoustical properties (velocity and attenuation) of monochromatic and transient shear waves in a large frequency range (300 - 1500

Cédric Schmitt; Antoine Bruhat; Anis Hadj Henni; Guy Cloutier

2008-01-01

164

HEAO 1 observations of X-ray emission from flares on dMe stars  

NASA Technical Reports Server (NTRS)

The paper reports the detection of two X-ray flares from each of the nearby dMe stars, AT Mic and AD Leo, with the A-2 experiment on board HEAO 1. A spectrum obtained during the brighter AT Mic flare, the first X-ray spectrum of a stellar flare, is well matched by a thermal model with a temperature 3 x 10 to the 7 K and an iron K-alpha emission line. The X-ray luminosities derived are in the range 1.3-16 x 10 to the 30th ergs/s, while emission measures are in the range 1.1-14 x 10 to the 53rd/cu cm. The estimated Lx/Lopt ratios exceed unity and are inconsistent with Mullan's flare model. Several scenarios to explain this discrepancy are proposed.

Kahn, S. M.; Mason, K. O.; Bowyer, C. S.; Linsky, J. L.; Haisch, B. M.; White, N. E.; Pravdo, S. H.

1979-01-01

165

GSC2314-0530: the shortest-period eclipsing system with dMe components  

NASA Astrophysics Data System (ADS)

CCD photometric observations in VRI colours and spectroscopic observations of the newly discovered eclipsing binary GSC2314-0530 (NSVS6550671) with dMe components and a very short period of P = 0.192636d are presented. The simultaneous light-curve solution and radial velocity solution allow us to determine the global parameters of GSC2314-0530: T1 = 3735K T2 = 3106K pc. The chromospheric activity of its components is revealed by strong emission in the H? line (with mean EW = 5Å) and several observed flares. Empirical relations for mass-, mass-radius and mass-temperature are derived on the basis of the parameters of known binaries with low-mass dM components.

Dimitrov, Dinko P.; Kjurkchieva, Diana P.

2010-08-01

166

Natural 4-hydroxy-2,5-dimethyl-3(2H)-furanone (Furaneol®).  

PubMed

4-Hydroxy-2,5-dimethyl-3(2H)-furanone (HDMF, furaneol®) and its methyl ether 2,5-dimethyl-4-methoxy-3(2H)-furanone (DMMF) are import aroma chemicals and are considered key flavor compounds in many fruit. Due to their attractive sensory properties they are highly appreciated by the food industry. In fruits 2,5-dimethyl-3(2H)-furanones are synthesized by a series of enzymatic steps whereas HDMF is also a product of the Maillard reaction. Numerous methods for the synthetic preparation of these compounds have been published and are applied by industry, but for the development of a biotechnological process the knowledge and availability of biosynthetic enzymes are required. During the last years substantial progress has been made in the elucidation of the biological pathway leading to HDMF and DMMF. This review summarizes the latest advances in this field. PMID:23765232

Schwab, Wilfried

2013-01-01

167

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

168

Sorbents for High Temperature Removal of Arsenic from Coal-Derived Synthesis Gas  

Microsoft Academic Search

Gasification technologies convert coal and other heavy feedstocks into synthesis gas feed streams that can be used in the production of a wide variety of chemicals, ranging from hydrogen through methanol, ammonia, acetic anhydride, dimethyl ether (DME), methyl tertiary butyl ether (MTBE), high molecular weight liquid hydrocarbons and waxes. Syngas can also be burned directly as a fuel in advanced

G. O. Alptekin; R. Copeland; M. Dubovik; Y. Gershanovich

2002-01-01

169

Degradation of alkyl ethers, aralkyl ethers, and dibenzyl ether by Rhodococcus sp. strain DEE5151, isolated from diethyl ether-containing enrichment cultures.  

PubMed

Twenty strains isolated from sewage sludge were found to degrade various ethers, including alkyl ethers, aralkyl ethers, and dibenzyl ether. In Rhodococcus strain DEE5151, induction of ether degradation needed substrates exhibiting at least one unsubstituted Calpha-methylene moiety as the main structural prerequisite. The cleavage reaction observed with anisole, phenetole, and dibenzyl ether indicates that the initial oxidation occurs at such respective Calpha positions. Diethyl ether-induced strain DEE5151 degraded dibenzyl ether via intermediately accumulated benzoic acid. Phenetole seems to be subject also to another ether-cleaving enzyme. Other strains of this group showed different enzymatic activities towards the substrate classes investigated. PMID:15240329

Kim, Yong-Hak; Engesser, Karl-Heinrich

2004-07-01

170

A new diphenyl ether from marine-derived fungus Aspergillus sp. B-F-2.  

PubMed

A new diphenyl ether dimethyl 2,3'-dimethylosoate (1) together with three known compounds monomethylsulochrin (2), emodin (3), and questin (4) were isolated through bioassay-guided fractionations from the culture of a marine-derived fungus Aspergillus sp. B-F-2. The structures of these compounds were determined by spectroscopic methods. Cytotoxicities of compounds 1 and 2 against K562 cell line were preliminarily evaluated by the MTT method and flow cytometry. PMID:16915822

Liu, Rui; Zhu, Weiming; Zhang, Yapeng; Zhu, Tianjiao; Liu, Hongbing; Fang, Yuchun; Gu, Qianqun

2006-06-01

171

[6,6?-Bis(1,1-di-methyl-eth-yl)-4,4?-dimethyl-2,2?-methyl-enediphenolato-?2 O,O?]di-chlorido-(9H-fluoren-9-ol-?O)titanium(IV)-fluorene-diethyl ether (1/0.5/1)  

PubMed Central

The title adduct, [TiCl2(C23H30O2)(C13H10O]·0.5C13H10·C4H10O, is a monomer with a trigonal–bypyramidal coordination sphere of the TiIV atom in which the ligand O atoms of the bidentate diphenolate anion are located in both apical and equatorial positions. Chloride ligands occupy the remaining two equatorial sites of the trigonal bypyramid with the fluoren-9-ol O atom occupying the other apical site. The hy­droxy group H atom of this latter group is hydrogen bonded to an O atom of a non-coordinating diethyl ether mol­ecule. The title compound also contains a further fluorene solvent mol­ecule, which lies across a centre of symmetry and which is equally disordered over an inversion centre.

Nielson, Alastair J.; Shen, Chaohong; Waters, Joyce M.

2013-01-01

172

Molecular Structure of Ethyl ether  

NSDL National Science Digital Library

Divinyl ether is a highly volatile colorless liquid. This compound can be synthesized from dichloroethyl ether by treatment with alkali. It is used by medical practitioners as an inhalation anesthetic for short operations. This chemical is also used to synthesize co-polymers for clear plastic bottles. A word of caution, ethers are known to form peroxides, which are can potentially lead to an explosion. Therefore, one should periodically test for peroxides using a test such as the potassium iodide detection method.

2002-10-01

173

A comparison of two position estimate algorithms that use ILS localizer and DME information. Simulation and flight test results  

NASA Technical Reports Server (NTRS)

Simulation and flight tests were conducted to compare the accuracy of two algorithms designed to compute a position estimate with an airborne navigation computer. Both algorithms used ILS localizer and DME radio signals to compute a position difference vector to be used as an input to the navigation computer position estimate filter. The results of these tests show that the position estimate accuracy and response to artificially induced errors are improved when the position estimate is computed by an algorithm that geometrically combines DME and ILS localizer information to form a single component of error rather than by an algorithm that produces two independent components of error, one from a DMD input and the other from the ILS localizer input.

Knox, C. E.; Vicroy, D. D.; Scanlon, C.

1984-01-01

174

Molecular Structure of Dimethyl sulfide  

NSDL National Science Digital Library

Dimethyl sulfide results from malt, and from the short or weak boil of wort, slow chilling, or bacterial infection during beer-brewing processes. Also, dimethyl sulfide is found in large amounts in the oceans when the phytoplankton bloom releases it. It is used as a solvent for a variety of organic and inorganic materials. It is employed as a pre-sulfiding agent for catalysts in the refinery and petrochemical manufacturing process, and is also used in steel mill furnaces to control dusting.

2002-10-10

175

Poly(arylene ether)s That Resist Atomic Oxygen  

NASA Technical Reports Server (NTRS)

Novel poly(arylene ether)s containing phosphine oxide (PAEPO's) made via aromatic nucleophilic displacement reactions of activated aromatic dihalides (or, in some cases, activated aromatic dinitro compounds) with new bisphenol monomers containing phosphine oxide. Exhibited favorable combination of physical and mechanical properties and resistance to monatomic oxygen in oxygen plasma environment. Useful as adhesives, coatings, films, membranes, moldings, and composite matrices.

Connell, John W.; Hergenrother, Paul; Smith, Joseph G., Jr.

1994-01-01

176

Efficient synthesis of (2 R,3 R)- and (2 S,3 S)-2,3-diaminobutane-1,4-diol and their dibenzyl ethers  

Microsoft Academic Search

(2R,3R)-2,3-Diaminobutane-1,4-diol 6 and its dibenzyl ether 7 were efficiently synthesized starting from L-tartaric acid 1a. The crucial step, debenzylation of intermediate dibenzyloxydiazide 4, was accomplished in good yield by boron trichloride-dimethyl sulfide complex. The enantiomeric series was similarly obtained starting from D-tartaric acid.

Andreas Scheurer; Paul Mosset; Rolf W. Saalfrank

1997-01-01

177

Kinetics of complexation of the macrocyclic ethers 18C6 and 12C4 with LiAsF/sub 6/ in 1,2-dimethoxyethane at 25C  

SciTech Connect

Ultrasonic relaxation spectra of the systems LiAsF/sub 6/ added to the macrocyclic ethers 18-crown-6 (18C6) or 12-crown-4 (12C4), in molar ratio R approx. = 1, in the solvent 1,2-dimethoxyethane (DME) at t = 25/sup 0/C, are reported. The concentration range covered was 0.05-0.25 M for 18C6 and 0.1-0.3 M for 12C4. Ancillary electrical conductance data for the same systems in the concentration range 10/sup -4/ to approx. 0.05 M at 25.00/sup 0/C reveal that the lithium-macrocycle interaction is weak, the conductance data being the same up to approx. 10/sup -2/ M, within experimental error of the data for the electrolyte alone in DME. 9 references, 5 figures, 2 tables.

Richman, H.; Harada, Y.; Eyring, E.M.; Petrucci, S.

1985-05-23

178

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

179

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.

Foundation, Wgbh E.

2004-02-20

180

Method for Modifying Polyhydroxy Ethers.  

National Technical Information Service (NTIS)

The patent application provides a method for modifying polyhydroxy eithers, derived from epichlorohydrin and bisphenol A. It comprises mixing such an ether with a material selected from the group consisting of dianisidine diisocyanate, polymethylene polyp...

Dauksys

1972-01-01

181

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

182

Bis(dimethyl-ammonium) tetra-chlorido-dimethyl-stannate(IV)  

PubMed Central

Regular crystals of the title compound, (C2H8N)2[Sn(CH3)2Cl4], were obtained by reacting SnMe2Cl2 with (CH3)2NH·HCl in ethanol in a 1:1 ratio. The Sn atom lies on a center of symmetry and is six-coordinated. It has a distorted octahedral SnC2Cl4 environment with the Cl atoms in cis positions. The Cl atoms are connected to dimethyl­ammonium cations through N—H?Cl hydrogen bonds, forming an infinite chain extending parallel to [010].

Diop, Tidiane; Diop, Libasse; Michaud, Francois

2011-01-01

183

(R,R)-Disynephrine ether bis-(hydrogen sulfate).  

PubMed

THE ASYMMETRIC UNIT OF THE TITLE COMPOUND [SYSTEMATIC NAME: (R,R)-2,4-bis-(4-hydroxy-phen-yl)-N,N'-dimethyl-3-oxapentane-1,5-diammonium bis-(hydrogen sulfate)], C(18)H(26)N(2)O(3) (2+)·2HSO(4) (-), contains one half-cation and one hydrogen sulfate anion. The cation has crystallographically imposed twofold symmetry with the rotation axis passing through the central ether O atom. Hydrogen bonds between the hydr-oxy group and amine H atoms of the cation to two hydrogen sulfate anions link the three ions in a ring motif. A three-dimensional network is accomplished by additional O-H?O hydrogen bonds between the anions and by N-H?O hydrogen bonds between the cations. Disorder with equally occupied sites affects the H-atom position in the anion. PMID:21583478

Arbuckle, William; Kennedy, Alan R; Morrison, Catriona A

2009-01-01

184

Space, Time, Ether, and Kant  

NASA Astrophysics Data System (ADS)

This dissertation focused on Kant's conception of physical matter in the Opus postumum. In this work, Kant postulates the existence of an ether which fills the whole of space and time with its moving forces. Kant's arguments for the existence of an ether in the so-called Ubergang have been acutely criticized by commentators. Guyer, for instance, thinks that Kant pushes the technique of transcendental deduction too far in trying to deduce the empirical ether. In defense of Kant, I held that it is not the actual existence of the empirical ether, but the concept of the ether as a space-time filler that is subject to a transcendental deduction. I suggested that Kant is doing three things in the Ubergang: First, he deduces the pure concept of a space-time filler as a conceptual hybrid of the transcendental object and permanent substance to replace the category of substance in the Critique. Then he tries to prove the existence of such a space-time filler as a reworking of the First Analogy. Finally, he takes into consideration the empirical determinations of the ether by adding the concept of moving forces to the space -time filler. In reconstructing Kant's proofs, I pointed out that Kant is absolutely committed to the impossibility of action-at-a-distance. If we add this new principle of no-action-at-a-distance to the Third Analogy, the existence of a space-time filler follows. I argued with textual evidence that Kant's conception of ether satisfies the basic structure of a field: (1) the ether is a material continuum; (2) a physical quantity is definable on each point in the continuum; and (3) the ether provides a medium to support the continuous transmission of action. The thrust of Kant's conception of ether is to provide a holistic ontology for the transition to physics, which can best be understood from a field-theoretical point of view. This is the main thesis I attempted to establish in this dissertation.

Wong, Wing-Chun Godwin

185

Surface modification of segmented poly(ether urethane) by grafting sulfo ammonium zwitterionic monomer to improve hemocompatibilities  

Microsoft Academic Search

Segmented poly(ether urethane) (SPEU) was synthesized from 4,4?-diphenylmethane-diisocyanate, polytetramethylene glycol and 1,4-butandiol. SPEU was hydroxylated by potassium peroxosulfate and N,N-dimethyl-N-methacryloxyethyl-N-(3-sulfopropyl) ammonium was grafted onto hydroxylated SPEU using ceric ammonium nitrate as initiator. The bulk characterization of synthesized SPEU was investigated by FTIR and equilibrium water content. Surface analysis of grafted SPEU film was studied by ATR-FTIR, electron spectroscopy for chemical

Zhang Jun; Yuan Youling; Wu Kehua; Shen Jian; Lin Sicong

2003-01-01

186

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...721.10099 Dialkyl dimethyl ammonium carbonate (generic). (a...generically as dialkyl dimethyl ammonium carbonate (1:1) (PMN...

2010-07-01

187

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

Code of Federal Regulations, 2010 CFR

...2009-07-01 false Dialkyl dimethyl ammonium carbonate (generic). 721.10099...721.10099 Dialkyl dimethyl ammonium carbonate (generic). (a...generically as dialkyl dimethyl ammonium carbonate (1:1) (PMN...

2009-07-01

188

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

189

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

190

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

191

Spin density distribution and electronic states in (DMe-DCNQI)2M (M=Li,Ag,Cu) from high-resolution solid-state NMR  

NASA Astrophysics Data System (ADS)

We experimentally determined the spin density distribution to investigate the electronic states of the (DMe-DCNQI)2M systems, where M is Li, Ag, and Cu. The Knight shift is measured with solid-state high-resolution NMR of H1 and C13 and is analyzed together with the reported N15 data. The Knight shift data at each atom of the DMe-DCNQI molecule give the ? -electron spin distribution of the Li salt, which might correspond to the charge distribution in the insulating and localized spin system of the Li salt. The average fraction of the spin susceptibility ?DCNQI/?0 in the DMe-DCNQI molecule of the Ag and Cu salts relative to that of the Li salt is obtained to be 0.82 and 0.71, respectively. Thus, if the valence of the Ag ion is unity, the DMe-DCNQI molecule of the Ag salt has the missing spin fraction by 0.18. One possible origin of this missing spin is a modification of the lowest unoccupied molecular orbital of the DMe-DCNQI molecule due to the ?-d hybridization with the Agdxy orbitals, which could be one of the origins for the difference of the physical properties from the Li salt, as in the enhancement of the charge hopping rate between the neighboring DMe-DCNQI columns in the Ag salt. In the Cu salt case, the missing spin fraction of 0.29 would correspond to the d -spin hole number of 0.28 of the Cudxy orbital. Finally, it is stressed that all the present results are consistent with both the first-principles calculation and the X-ray photoelectron spectroscopy study.

Shinohara, Yukie; Kazama, Shigeo; Mizoguchi, Kenji; Hiraoka, Maki; Sakamoto, Hirokazu; Masubuchi, Shin-Ichi; Kato, Reizo; Hiraki, Koichi; Takahashi, Toshihiro

2007-07-01

192

DME synthesis from synthesis gas on the admixed catalysts of Cu\\/ZnO\\/Al 2O 3 and ZSM-5  

Microsoft Academic Search

Na-ZSM-5 and H-ZSM-5 catalysts with three different Si\\/Al ratios were prepared to investigate methanol dehydration and direct DME synthesis. The acid strength of ZSM-5 increased with a decrease in the Si\\/Al ratios and methanol dehydration rate was maximized on H-ZSM-5(30) with the highest acid strength. The direct DME synthesis was conducted on the admixed catalysts of Cu\\/ZnO\\/Al2O3 and ZSM-5. The

Ji-Hyun Kim; Min Jo Park; Sun Jin Kim; Oh-Shim Joo; Kwang-Deog Jung

2004-01-01

193

Influence of solid acid catalyst on DME production directly from synthesis gas over the admixed catalyst of Cu\\/ZnO\\/Al 2O 3 and various SAPO catalysts  

Microsoft Academic Search

This study focused on the effect of solid acid catalyst on the catalytic performance in direct DME synthesis. The various SAPO catalysts were prepared to perform methanol dehydration and direct DME synthesis. In methanol dehydration, SAPO-34 and -18 with strong acid sites and showed high initial activity, but deactivated rapidly. This is mainly attributed to the formation of coking materials

Kye Sang Yoo; Ji-Hyun Kim; Min-Jo Park; Sun-Jin Kim; Oh-Shim Joo; Kwang-Deog Jung

2007-01-01

194

Acyl Iodides in Organic Synthesis: VI. Reactions with Vinyl Ethers  

Microsoft Academic Search

Reactions of acetyl iodide with butyl vinyl ether, 1,2-divinyloxyethane, phenyl vinyl ether, 1,4-di-vinyloxybenzene, and divinyl ether were studied. Vinyl ethers derived from aliphatic alcohols (butyl vinyl ether and 1,2-divinyloxyethane) react with acetyl iodide in a way similar to ethyl vinyl ether, i.e., with cleavage of both O–Csp2 and Alk–O ether bonds. From butyl vinyl ether, a mixture of vinyl iodide,

M. G. Voronkov; A. A. Trukhina; N. N. Vlasova

2004-01-01

195

New polymers of vinyl ethers  

Microsoft Academic Search

1.A new, previously undescribed homogeneous catalyst was prepared for the stereospecific polymerization of vinyl ethers at room temperature.2.Polymers prepared from butyl vinyl, isobutyl vinyl, cyclohexyl vinyl, and decahydro-2-naphthyl vinyl ethers in good yields in presence of this catalyst were characterized by their viscosities, molecular weights, solubilities, and x-ray diagrams.3.Study of a heterogeneous catalyst system consisting of TiCl4, LiC3H7, and Al(i-C4H9)3

A. V. Bogdanova; M. F. Shostakovskii; S. Shamakhmudova

1964-01-01

196

Method of Converting Certain Allylic Ethers to Dienol Ethers.  

National Technical Information Service (NTIS)

This patent application pertains to a method of producing thebaine from codeine and oripavine from morphine which comprises (a) producing the 0-6 methyl ethers from codeine and morphine using potassium hydride and methyl iodide as the O-alkylation agents ...

H. Rapoport R. B. Barber

1976-01-01

197

Toughening of Diglycidyl Ether of Bisphenol-A Epoxy Resin Using Poly (Ether Ether Ketone) with Pendent Ditert-Butyl Groups  

Microsoft Academic Search

Poly(ether ether ketone) (PEEKDT), hydroxyl terminated poly(ether ether ketone) (PEEKDTOH) and fluorine terminated poly (ether ether ketone) (PEEKDTF) with pendent ditert-butyl groups were synthesized by the nucleophilic substitution reaction of 4,4?-difluorobenzophenone with 2,5-ditert-butylhydroquinone in N-methyl-2-pyrrolidone medium using anhydrous potassium carbonate as catalyst. Diglycidyl ether of bisphenol-A epoxy resin was blended with PEEKDT, PEEKDTOH, and PEEKDTF, and cured with 4,4?-diaminodiphenylsulfone (DDS).

Bejoy Francis; R. Ramaswamy; V. Lakshmana Rao; Sabu Thomas

2006-01-01

198

Flares on dMe Stars: IUE (International Ultraviolet Explorer) and Optical Observations of AT Mic, and Comparison of Far-Ultraviolet Stellar and Solar Flares.  

National Technical Information Service (NTIS)

In the paper the authors describe observations and analysis of a large flare event on a dMe star, detected by the International Ultraviolet Explorer (IUE). They compare its far-ultraviolet spectrum with those of other stellar flares and also a large solar...

G. E. Bromage K. J. H. Phillips P. L. Dufton A. E. Kingston

1986-01-01

199

Flares on DMe Stars: IUE (International Ultraviolet Explorer) and Optical Observations of At Mic, and Comparison of Far-Ultraviolet Stellar and Solar Flares.  

National Technical Information Service (NTIS)

The paper concerns observations of a large flare event on the dMe star At Mic, detected by the International Ultraviolet Explorer. The far-ultraviolet spectra of the flare is compared with those of other stellar flares, and also with a large solar flare r...

G. E. Bromage K. J. H. Phillips P. L. Dufton A. E. Kingston

1986-01-01

200

Fluoride-mediated elimination of allyl sulfones: application to the synthesis of a 2,4-dimethyl-A-ring vitamin D3 analogue.  

PubMed

A coupling strategy for the synthesis of 2,4-dimethyl-1?,25(OH)(2)D(3) is achieved which involves methylation of a pro-A ring vinyl sulfone and in situ traping of the allyl sulfonyl anion with a CD ring allyl chloride. TBAF-promoted 1,2-eliminative desulfonylation and concomitant silyl ether deprotection gives the vitamin D(3) analogue. PMID:22533543

Sikervar, Vikas; Fleet, James C; Fuchs, Philip L

2012-06-01

201

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

PubMed Central

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

Ensminger, Michael P.; Hess, F. Dan

1985-01-01

202

Study on the application of D30 blended fuel  

Microsoft Academic Search

The paper introduces application of D6114ZLQB turbocharged and cold diesel engine fueled with Dimethyl Ether and diesel, including the power performance, economical efficiency, and exhaust emission characteristics. Based on the analysis on the properties of D30 (the ratio of DME and diesel is 3 to 7 )blended fuel, a series of job have been done such as designing the fuel

Zhu Jianjun; Wang Tie; Kou Ziming

2010-01-01

203

Slurry Reactors for Gas-to-Liquid Processes:  A Review  

Microsoft Academic Search

With the dramatic increase in the international oil price, gas-to-liquid processes of Fischer -Tropsch (FT) synthesis, methanol synthesis, and dimethyl ether (DME) synthesis have become increasingly important and received much attention from both academic and industrial interests. The slurry reactor has the advantages of simple construction, excellent heat transfer performance, online catalyst addition and withdrawal, and a reasonable interphase mass

Tiefeng Wang; Jinfu Wang; Yong Jin

2007-01-01

204

Complex Formation between Dimethyl Methylphosphonate and Hexafluoroisopropanol.  

National Technical Information Service (NTIS)

A solvent/water partitioning method was used to measure the complex formation between dimethyl methylphosphonate (DMMP) and hexafluoroisopropanol (HFIP). The highest formation constant was obtained when n-hexane was used as the partitioning solvent. Other...

D. C. Leggett

1990-01-01

205

21 CFR 172.133 - Dimethyl dicarbonate.  

Code of Federal Regulations, 2013 CFR

...treatment, filtration, or other technologies prior to the use of dimethyl dicarbonate: (1) In wine, dealcoholized wine, and low alcohol wine in an amount not to exceed 200 parts per million. (2) In ready-to-drink teas in an...

2013-04-01

206

The Millimeter- and Submillimeter-Wave Spectrum of the trans-trans Conformer of Diethyl Ether (C2H5OC2H5)  

NASA Astrophysics Data System (ADS)

Since dimethyl ether is found to have a high abundance in hot cores, it is reasonable to search among such sources for detectable abundances of the more complex analogs ethyl methyl ether (C2H5OCH3) and diethyl ether (C2H5OC2H5). Indeed, preliminary detections of both complex ethers have been reported. Definitive interstellar searches do require laboratory spectra, however, but for many years only low-frequency data have been available for both of these species. Following our recent study of the millimeter-wave and submillimeter-wave spectrum of ethyl methyl ether, we report here the study of the millimeter- and submillimeter-wave spectrum of the lowest energy conformer of diethyl ether. With four different spectrometers, over 1000 new spectral lines have been measured and analyzed at frequencies up to 350 GHz. Fitting the data to a set of spectroscopic parameters from the Watson A-reduced form of the asymmetric-top Hamiltonian has allowed us to predict the frequencies and intensities of many more transitions through 400 GHz. A more precise determination of the electric dipole moment of diethyl ether was also carried out, resulting in ?=?b=1.0976(9) D.

Medvedev, Ivan; Winnewisser, Manfred; De Lucia, Frank C.; Herbst, Eric; Yi, Enyi; Leong, Lai Peng; Bettens, Ryan P. A.; Bia?kowska-Jaworska, Ewa; Desyatnyk, Oleksandr; Pszczó?kowski, Lech; Kisiel, Zbigniew

2003-10-01

207

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

Microsoft Academic Search

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

Mingchao Shen; Y. Vickie Pan; Matthew S. Wagner; Kip D. Hauch; David G. Castner; Buddy D. Ratner; Thomas A. Horbett

2001-01-01

208

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.

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

1984-01-01

209

Alcohols, ethers, carbohydrates, and related compounds. III. The 1,2-dimethoxyethane system.  

PubMed

Ethylene glycol, its dimethyl ether, and some related compounds have been studied using the MM4 molecular mechanics force field. The MM4 calculated structural and energetic results have been brought into satisfactory agreement with a considerable number of experimental data and MP2/6-311++G(2d,2p) ab initio calculations. The heats of formation of these compounds are also well calculated. The MM4 ethylene glycol conformations in particular are in good agreement, both geometrically and in terms of energy, with those from the ab initio calculations. The corresponding dimethyl ether is of special interest, because it has been suggested that the trans-gauche conformation is unusually stable due to the hydrogen bonding of a hydrogen on a methyl group with the more distant oxygen. It is shown in the present work that while this conformation is more stable than might have been expected, the energy is adequately calculated by MM4 without using any hydrogen bonding between the Cbond;H bond and the oxygen. If such hydrogen bonding occurs, it amounts to no more than about 0.5 kcal/mol in energy, and is too small to detect with certainty. Additionally, energetic relationships in trans-1,2-dimethoxycyclohexane, 1,3,5,7-tetraoxadecalin, and 3-methoxytetrahydropyran have been studied, and the calculated results are compared with experimental information, which is adequately reproduced. PMID:12868112

Lii, Jenn-Huei; Chen, Kuo-Hsiang; Grindley, T Bruce; Allinger, Norman L

2003-09-01

210

Viscosity constant for polymers of vinyl ethers  

Microsoft Academic Search

1.On the basis of a study of the molecular weights and viscosities of solutions of alkoxy compounds and separate fractions of poly(alkyl vinyl ethers) the constant of Staudinger's formula was determined for the polymers of ethyl vinyl, isopropyl vinyl, and butyl vinyl ethers.2.The effect of the chemical structure of the alkoxy group in polymers of vinyl ethers on the constant

M. F. Shostakovskil; V. A. Gladyshevskaya; R. I. Baikova

1959-01-01

211

Effect of water on liquid phase DME synthesis from syngas over hybrid catalysts composed of Cu\\/ZnO\\/Al 2 O 3 and ?-Al 2 O 3  

Microsoft Academic Search

DME synthesis from syngas via methanol has been carried out in a single-stage liquid phase reactor. Cu\\/ ZnO\\/Al2O3 and ?-Al2O3 were used together as methanol synthesis catalyst and dehydration catalyst, respectively. The influence of water on the catalytic\\u000a system was investigated mainly. Water affected the activity of methanol dehydration catalyst as well as methanol synthesis\\u000a catalyst. Thus, removal of water

Hak-Ju Kim; Heon Jung; Kwan-Young Lee

2001-01-01

212

A cell-based system to identify and characterize the molecular mechanism of drug-metabolizing enzyme (DME) modulators.  

PubMed

Many naturally occurred or synthetic compounds can modulate the body's drug-metabolizing enzymes to enhance carcinogen detoxification, and some have demonstrated remarkable cancer prevention effects. Understanding the molecular mechanism behind each candidate agent is critically important in designing rational cancer chemoprevention strategies. In this work, we have employed a set of molecular mechanism-based assays and characterized eight classes of known drug-metabolizing enzyme (DME) modulators in a cellular system. Examination of mRNA and protein levels of representative phase I and phase II enzymes validated the results obtained in our cell-based system. Our data confirmed that the antioxidant ethoxyquin (EQ) and the isothiolcyanate sulfurophane (SFP) exclusively activate the antioxidant response element (ARE), and thus represent monofunctional inducers. We were also able to reclassify some compounds, and to use the system to identify structure-activity relationships among structurally related but different compounds. Finally, this cell-based system permitted us to identify a potential novel mechanism for cross-talk between the ARE and the xenobiotic response element (XRE)-mediated pathways. PMID:15130766

Miao, Weimin; Hu, Lianggao; Kandouz, Mustapha; Hamilton, David; Batist, Gerald

2004-05-15

213

40 CFR 721.3440 - Haloalkyl substituted cyclic ethers.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 false Haloalkyl substituted cyclic ethers. 721.3440 Section 721... § 721.3440 Haloalkyl substituted cyclic ethers. (a) Chemical substance and...chemical substances haloalkyl substituted cyclic ethers (PMN P-85-368 and...

2010-07-01

214

40 CFR 721.3440 - Haloalkyl substituted cyclic ethers.  

Code of Federal Regulations, 2010 CFR

...2009-07-01 false Haloalkyl substituted cyclic ethers. 721.3440 Section 721... § 721.3440 Haloalkyl substituted cyclic ethers. (a) Chemical substance and...chemical substances haloalkyl substituted cyclic ethers (PMN P-85-368 and...

2009-07-01

215

40 CFR 721.10551 - Bisphenol S mono ether (generic).  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Bisphenol S mono ether (generic). 721.10551...Chemical Substances § 721.10551 Bisphenol S mono ether (generic). (a...chemical substance identified generically as bisphenol S mono ether (PMN...

2013-07-01

216

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

217

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

218

Composition-explicit distillation curves of diesel fuel with glycol ether and glycol ester oxygenates: fuel analysis metrology to enable decreased particulate emissions.  

PubMed

We recently introduced several important improvements in the measurement of distillation curves of complex fluids. The modifications to the classical measurement provide for (1) a composition-explicit data channel for each distillate fraction (for both qualitative and quantitative analysis), (2) temperature measurements that are true thermodynamic state points that can be modeled with an equation of state, (3) temperature, volume, and pressure measurements of low uncertainty suitable for equation of state development, (4) consistency with a century of historical data, (5) an assessment of the energy content of each distillate fraction, (6) trace chemical analysis of each distillate fraction, and (7) corrosivity assessment of each distillate fraction. We have applied the new method to the measurement of rocket propellant, gasolines, jet fuels, and hydrocarbon crude oils. In this paper we presentthe application of the technique to representative diesel fuel and mixtures of diesel fuel with some of the more promising oxygenating agents; namely, the glycol ethers and glycol esters: tri(propylene glycol) methyl ether (TPM), dibutyl maleate (DBM), and an 80/ 20 (vol/vol) mixture of diethylene glycol methyl ether (DGME) + 1,2-dimethoxyethane (DME) a mixture often referred to as Cetaner. We present not only the distillation curves but also a chemical characterization of each fraction, and discuss the contrasts between the various mixtures. The measurements are significant as an environmental design tool for decreased particulate emissions. PMID:18983093

Smith, Beverly L; Ott, Lisa S; Bruno, Thomas J

2008-10-15

219

21 CFR 524.660a - Dimethyl sulfoxide solution.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Dimethyl sulfoxide solution. 524.660a Section 524.660a Food and Drugs FOOD...DOSAGE FORM NEW ANIMAL DRUGS § 524.660a Dimethyl sulfoxide solution. (a) Specifications. Dimethyl sulfoxide contains...

2013-04-01

220

Covariant Ether Theories and Special Relativity  

Microsoft Academic Search

The present paper defines “covariant ether theories” as all space-time theories that are alternative to special relativity theory (SRT), but nevertheless satisfy the general relativity principle. A general analysis of the properties of admissible space-time transformations shows that the number of such “covariant ether theories” is infinite, and that all these theories are indistinguishable from SRT with all experiments in

A. L. Kholmetskii

2003-01-01

221

Perfluorocyclobutane (PFCB) polyaryl ethers: versatile coatings materials  

Microsoft Academic Search

The cyclopolymerization of aromatic trifluorovinyl ether (TFVE) monomers offers a versatile route to a unique class of linear and network fluoropolymers containing the perfluorocyclobutyl (PFCB) linkage. Polymerization proceeds by a thermal — radical mediated — step-growth mechanism and provides well-defined polymers containing known fluoroolefin end groups. PFCB polymers combine the engineering thermoplastic nature of polyaryl ethers with fluorocarbon segments and

Dennis W. Smith Jr; David A. Babb; Hiren V. Shah; Adrienne Hoeglund; R. Traiphol; Dvora Perahia; Harold W Boone; Charles Langhoff; Mike Radler

2000-01-01

222

Extended Fizeau experiment and the ether  

Microsoft Academic Search

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

Brevik; Iver

2010-01-01

223

Stereoselective bromocyclization of allylated aldoxime ethers.  

PubMed

The intramolecular bromoamination of allylated aldoxime ethers leads first to isoxazolidinium salts which then undergo a skeletal rearrangement to form bromo-5,6-dihydro-4H-1,3-oxazines. Aliphatic aldoxime ethers with ?-protons undergo multiple brominations before rearrangement. PMID:24956967

Egart, Boris; Czekelius, Constantin

2014-08-01

224

An expedient synthesis of linden ether.  

PubMed

We here describe a comprehensive study on the preparation of the intensive flavor 3,9-epoxy-p-mentha-1,4(8)-diene (1). Key steps of the presented synthesis are the selective addition of MeLi to the keto-ester 7, the regioselective cyclization of the obtained triol to give the ethers 4 and 8 and the selective dehydration of ether 4 through the use of POCI3 and pyridine. It is worth noting that the presented synthesis represents the first expedient and reliable entry to ether 1. Being present in linden honey, 1 is also known as linden ether and it has been regarded as a potential marker for the authentication of the linden honey origin. Therefore, ether 1 can be used as a useful reference standard for the analysis of the natural flavors, as we demonstrated by means of its identification in a sample ofunifloral linden honey. PMID:24689197

Serra, Stefano; Cominetti, Alessandra A

2014-03-01

225

Synthesis of dimethyl 1,2-dihydroisoquinolines through the reaction of isoquinoline and dimethyl acetylenedicarboxylate in the presence of amides  

Microsoft Academic Search

Isoquinoline reacts smoothly with dimethyl acetylenedicarboxylate (DMAD) in the presence of amides to produce dimethyl 2-[1-[aryl(alkyl)carbonylamino]-2(1H)-isoquinolinyl]-2-butenedioates. Reaction of quinoline with DMAD in the presence of benzamide led to dimethyl 2-[1-[(phenylcarbonyl)amino]-2(1H)-quinolinyl]-2-butenedioate.

Issa Yavari; Majid Ghazanfarpour-Darjani; Maryam Sabbaghan; Zinatossadat Hossaini

2007-01-01

226

Lung injury in dimethyl sulfate poisoning  

SciTech Connect

Two manual laborers were exposed to dimethyl sulfate during work and sustained mucosal injury to the eyes and respiratory tract. In one of them, noncardiogenic pulmonary edema occurred and improved with high-dose methylprednisolone. On follow-up for 10 months, this patient developed persistent productive cough with no evidence of bronchiectasis or bronchial hyperreactivity.

Ip, M.; Wong, K.L.; Wong, K.F.; So, S.Y.

1989-02-01

227

Dimethyl Sulfoxide Effects on Isolated Fat Cells.  

National Technical Information Service (NTIS)

The ability of dimethyl sulfoxide to inhibit insulin-stimulated glucose oxidation is not the result of the increased lipolysis observed in the absence of insulin with DMSO. Free fatty acids have been shown to inhibit insulin action on fat cells but DMSO s...

P. B. Wieser

1983-01-01

228

Revisiting optical clearing with dimethyl sulfoxide (DMSO)  

Microsoft Academic Search

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 threefold reduction in the scattering of skin with topical DMSO application. With an in vivo window chamber

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

2009-01-01

229

Synthesis and Characteristics of Polyarylene Ether Sulfones.  

National Technical Information Service (NTIS)

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...

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

1981-01-01

230

Exploring the reactivity of tungsten bis(imido) dimethyl complexes with methyl aluminium reagents: implications for ethylene dimerization.  

PubMed

The reaction of [WCl2(NAr)2(DME)] (1) with excess Me3Al affords the dimethyl complex [WMe2(N{Ar}AlMe2{mu-Cl})(NAr)] (2), which on treatment with THF or MeAlCl2 yields [WMe2(NAr)2(THF)] (3) and [WMe2(N{Ar}AlMe(Cl){mu-Cl})(NAr)] (5), respectively. Complex 3 is unstable in solution dissociating to form [WMe2(NAr)2] (4) that may be isolated as an adduct with PMe3, [WMe2(NAr)2(PMe3)] (6). While complex 2 is inert towards ethylene, complex 3 reacts rapidly to afford a mixture of methane and but-1-ene (1:4). Neither complex 2 nor 3 react with propylene. Reaction of 3 with a C2H4/C2D4 (1:1) affords a mixture of isotopomers that is consistent with complete isotopic scrambling. The structures of complexes 1, 2, and 3 have been determined by X-ray diffraction. PMID:20567750

Wright, William R H; Batsanov, Andrei S; Howard, Judith A K; Tooze, Robert P; Hanton, Martin J; Dyer, Philip W

2010-08-14

231

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.

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

1993-01-01

232

A mild and selective deprotection of p-methoxybenzyl (PMB) ether by magnesium bromide diethyl etherate-methyl sulfide  

Microsoft Academic Search

The magnesium bromide diethyl etherate (MgBr2·OEt2)-methyl sulfide (Me2S) system is useful for the mild and chemo-selective deprotection of p-methoxybenzyl (PMB) ether in the presence of 1,3-diene, t-butyldimethylsilyl (TBDMS) ether, benzoate, benzyl ether and acetonide.

Toshihiko Onoda; Ryuichi Shirai; Shigeo Iwasaki

1997-01-01

233

On the problem of the polarography of diethyl ether peroxide  

Microsoft Academic Search

1.Simple ethers inhibit the reduction of low-molecular peroxides, including the peroxides of the ethers themselves. The reduction potential of diethyl ether peroxide against a background of 0.1 N solutions of HCl and LiCl (in the absence of ether) is equal to -0.21 V.2.Diethyl ether peroxide, isolated in pure form, undergoes a slow change accompanied by a decrease in the active

O. B. Iv

1964-01-01

234

METHYL TERTIARY-BUTYL ETHER (MTBE): Gasoline  

NSDL National Science Digital Library

This site gives an explanation of Methyl tertiary butyl ether (MTBE), also known as an oxygenate, a chemical compound used as a gasoline additive to enhance the octane and subsequently burn the fuel more completely.

2007-04-08

235

Dimethyl carbonate for environmentally benign reactions  

Microsoft Academic Search

Dimethyl carbonate (DMC) is a unique molecule having a versatile reactivity. The transesterification of DMC with phenol gives methyl phenyl carbonate, which is converted into diphenyl carbonate (DPC) by disproportionation. MoO3\\/SiO2 is an active catalyst for both reactions. DPC is an essential monomer in the non-phosgene route for polycarbonates. The methoxycarbonylation of aniline gives methyl N-phenyl carbamate in the presence

Yoshio Ono

1997-01-01

236

Characterization of Alternating Copolymers of Vinyl Ethers  

Microsoft Academic Search

Copolymerization of methyl 2-cyano-3-phenyl-2-propenoate (MCP) and 2-phenyl-1,1-dicyanoethene (PDE) with ethyl, n-butyl, i-butyl, 2-chloroethyl, and phenyl vinyl ethers in broad ranges of comonomer ratios always produces copolymers of an equimolar composition. The alternating structure of these copolymers was established by elemental analysis and by infrared, H? and C-NMR spectroscopy. Microstructure analysis of the copolymer of PDE and phenyl vinyl ether, as

Gregory B. Kharas; Julie M. Eaker; Himant Ajbani; Kenneth Watson

1995-01-01

237

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

238

Hydroxyl terminated poly(ether ether ketone) with pendent methyl group toughened epoxy resin: miscibility, morphology and mechanical properties  

Microsoft Academic Search

The synthesis, processing, thermal and mechanical properties and fracture toughness of epoxy resin formulated with hydroxyl terminated poly(ether ether ketone) with pendent methyl group are reported. Hydroxyl terminated poly(ether ether ketone) oligomers based on methyl hydroquinone (PEEKMOH) were synthesised from methylhydroquinone and 4,4?-difluorobenzophenone in N-methyl-2-pyrrolidone. PEEKMOH oligomers with different molecular weights were synthesised and characterised. Blends of diglycidyl ether of

Bejoy Francis; Sabu Thomas; Jesmy Jose; R. Ramaswamy; V. Lakshmana Rao

2005-01-01

239

Conformational equilibria in adducts of alcohols with ethers: the rotational spectrum of ethylalcohol-dimethylether.  

PubMed

The rotational spectra of two conformers of the molecular complex ethylalcohol-dimethylether were measured with pulsed-jet Fourier transform microwave spectroscopy. Both trans and gauche conformations of ethylalcohol are preserved in the complex, originating two conformations with dimethylether as the proton accepting unit. A switch of the conformational stability of ethyl alcohol is observed upon complexation with dimethyl ether, with the gauche form becoming the global minimum. The investigation of the O-D deuterated species allowed observing quantitatively the Ubbelohde effect, which is the shrinkage of the O???O distance of about 6 mÅ upon H?D isotopic substitution of the hydroxylic hydrogen participating in the O-H???O hydrogen bond. PMID:21698740

Evangelisti, Luca; Feng, Gang; Rizzato, Roberto; Caminati, Walther

2011-07-11

240

Ethylene glycol monomethyl ether and propylene glycol monomethyl ether: metabolism, disposition, and subchronic inhalation toxicity studies  

Microsoft Academic Search

Short-term and subchronic vapor inhalation studies have shown that there are pronounced differences in the toxicological properties of ethylene glycol monomethyl ether (EGME) and propylene glycol monomethyl ether (PGME). Overexposure to EGME has resulted in adverse effects on testes, bone marrow and lymphoid tissues in laboratory animals. PGME does not affect these tissues, and instead, overexposure to PGME has been

R. R. Miller; E. A. Hermann; J. T. Young; T. D. Landry; L. L. Calhoun

1984-01-01

241

Conformations and Barriers to Methyl Group Internal Rotation in Two Asymmetric Ethers: Propyl Methyl Ether and Butyl Methyl Ether  

NASA Astrophysics Data System (ADS)

The conformational preferences of the O-C-C-C unit are important in many biological systems with the unit generally preferring a gauche configuration compared to an anti configuration. Butyl methyl ether and propyl methyl ether provide very simple systems for this phenomenom to manifest. Pure rotational spectra of the title molecules have been recorded using chirped pulse Fourier transform microwave spectroscopy (CP-FTMW). In the case of butyl methyl ether, only one conformer has been observed. This conformer has torsional angles of COCC = 180°, OCCC = 62° and CCCC = 180° (anti-gauche-anti) and rotational constants of A = 10259.4591(33) MHz, B = 1445.6470(13) MHz, and C = 1356.2944(14) MHz. The rotational spectrum was doubled and has been analyzed to produce an effective barrier to methyl group internal rotation of 780(35) cm-1. A prior rotational spectroscopic study on propyl methyl ether had focused only on the high energy anti-anti conformer. We have analyzed spectra from the lowest energy anti-gauche conformer and the spectroscopic constants will be presented. A summary of the differences in conformational energies and methyl group internal rotation barriers for the class of aliphatic asymmetric ethers will be presented. K. N. Houk, J. E. Eksterowicz, Y.-D. Wu, C. D. Fuglesang, D. B. Mitchell. J. Am. Chem. Soc. 115 (4170), 1993. Hiroshi Kato, Jun Nakagawa, Michiro Hayashi. J. Mol. Spectrosc. 80 (272), 1980.

Long, B. E.; Dechirico, F.; Cooke, S. A.

2012-06-01

242

Microemulsion Systems with Rhodium Tris(3-sulfophenyl)phosphine Trisodium Salt Complex for Product Isolation and Catalyst Recycling in the Hydrogenation of Dimethyl Itaconate  

Microsoft Academic Search

Microemulsion systems with the nonionic surfactant p-tert-octylphenoxy polyethoxyethanol (OP9.5EO), the anionic surfactant dioctyl sulfosuccinate sodium salt (DOSS) and the narrow\\u000a range nonionic surfactant alkyl polyethylene glycol ether (C10EO5) were used as solvent systems in the catalytic hydrogenation\\u000a of dimethyl itaconate (DMI) catalysed by the water soluble catalyst complex Rh-TPPTS in order to achieve product isolation\\u000a and catalyst recycling. The DOSS

Juan S. Milano-Brusco; Jamal Touitou; Verena Strempel; Reinhard Schomäcker

2011-01-01

243

Excess molar enthalpies for the binary and ternary mixtures of ether compounds ( di -isopropyl ether, di -butyl ether, propyl vinyl ether) with ethanol and isooctane at 298.15 K  

Microsoft Academic Search

Excess molar enthalpy (H\\u000a E\\u000a ) data at 298.15 K are reported for the binary systems di-isopropyl ether (1)+ethanol (2), di-isopropyl ether (1)+isooctane (2), ethanol (1)+isooctane (2), di-butyl ether (1)+ethanol (2), di-butyl ether (1)+isooctane (2), propyl vinyl ether (1)+ethanol (2) and propyl vinyl ether (1)+isooctane (2). These data were\\u000a obtained by using an isothermal flow calorimeter. The experimental binary H

Moon-Gab Kim; So-Jin Park; In-Chan Hwang

2008-01-01

244

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

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Quaternary ammonium compounds, bis(fattyalkyl) dimethyl, salts... § 721.10666 Quaternary ammonium compounds, bis(fattyalkyl) dimethyl, salts...identified generically as quaternary ammonium compounds, bis(fattyalkyl) dimethyl,...

2013-07-01

245

40 CFR 721.10352 - Dimethyl terephthalate, polymer with alkyl diol and substituted benzoates (generic).  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Dimethyl terephthalate, polymer with alkyl diol and substituted benzoates...721.10352 Dimethyl terephthalate, polymer with alkyl diol and substituted benzoates...generically as dimethyl terephthalate, polymer with alkyl diol and substituted...

2013-07-01

246

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

Code of Federal Regulations, 2010 CFR

...2009-07-01 false Dialkyl dimethyl ammonium carbonate (2:1) (generic...721.10100 Dialkyl dimethyl ammonium carbonate (2:1) (generic...generically as dialkyl dimethyl ammonium carbonate (2:1) (PMN...

2009-07-01

247

21 CFR 172.824 - Sodium mono- and dimethyl naphthalene sulfonates.  

Code of Federal Regulations, 2010 CFR

... Sodium mono- and dimethyl naphthalene sulfonates...additive sodium mono- and dimethyl naphthalene sulfonates...crystallization of sodium carbonate in an amount not to...Act: (1) Sodium carbonate produced in accordance...of sodium mono- and dimethyl naphthalene...

2010-01-01

248

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...721.10100 Dialkyl dimethyl ammonium carbonate (2:1) (generic...generically as dialkyl dimethyl ammonium carbonate (2:1) (PMN...

2010-07-01

249

21 CFR 172.824 - Sodium mono- and dimethyl naphthalene sulfonates.  

Code of Federal Regulations, 2010 CFR

... Sodium mono- and dimethyl naphthalene sulfonates...additive sodium mono- and dimethyl naphthalene sulfonates...crystallization of sodium carbonate in an amount not to...Act: (1) Sodium carbonate produced in accordance...of sodium mono- and dimethyl naphthalene...

2009-04-01

250

40 CFR 721.6167 - Piperdinium, 1,1-dimethyl-, chloride.  

Code of Federal Regulations, 2013 CFR

... Piperdinium, 1,1-dimethyl-, chloride. 721.6167 Section 721.6167... Piperdinium, 1,1-dimethyl-, chloride. (a) Chemical substance and significant...as piperdinium, 1,1-dimethyl-, chloride. (PMN P-02-207; CAS No....

2013-07-01

251

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.

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

2012-01-01

252

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

253

Extended Fizeau experiment and the ether  

NASA Astrophysics Data System (ADS)

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 Kostelecký and collaborators in several recent papers.

Brevik, Iver

2010-11-01

254

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

255

Dibenzotetraaza crown ethers: a new family of crown ethers based on o-phenylenediamine.  

PubMed

Dibenzotetraaza (DBTA) crown ethers possess two o-phenylenediamine moieties. They are homologues of dibenzo crown ether phase-transfer catalysts and were prepared from the condensation of benzimidazoles with oligo(ethyleneglycol) dichlorides and oligo(ethyleneglycol) ditosylates. Compounds with ring sizes ranging from 18-crown-6 to 42-crown-14 were prepared. In addition, various altered benzimidizoles were used to produce DBTA crown ethers with modified substituents and ether bridges, as well as benzimidazolidine crown ethers. The synthetic approach presented here proved to be a convenient route to a new family of crown ethers with overall yields of up to 48% based on the benzimidazole. Yields for the ring-closing step were generally high, ranging from 51% to 94%, without the need for high-dilution conditions. Reaction of the DBTA crown ethers with alkyl and benzyl halides was found to be a facile way to obtain the corresponding tetra(N-organyl) compounds. Picrate extraction studies were carried out to determine phase-transfer catalytic capabilities. Extraction efficiencies for alkali-metal ions were lower than those for dibenzo-18-crown-6. Efficiencies were higher for other metal ions, with some selectivity for Pb(2+). Tetra(N-methyl) DBTA-18-crown-6 generally exhibited higher extraction efficiencies than its N-H analogue, but the selectivity was lower. PMID:16018672

Hausner, Sven H; Striley, Cynthia A F; Krause-Bauer, Jeanette A; Zimmer, Hans

2005-07-22

256

Dimethyl carbonate as a modern green reagent and solvent  

NASA Astrophysics Data System (ADS)

Published data on dimethyl carbonate as a safe reagent and solvent in organic synthesis are generalized and analyzed. The methods of dimethyl carbonate preparation and its use as methylating and carboxymethylating reagent are considered. The attention is focused on the environmentally safe processes corresponding to the green chemistry principles.

Aricò, F.; Tundo, Pietro

2010-08-01

257

IRIS Toxicological Review of Decabromodiphenyl Ether (2008 Final)  

EPA Science Inventory

EPA is announcing the release of the final report, Toxicological Review of Decabromodiphenyl Ether: in support of the Integrated Risk Information System (IRIS) . The updated Summary for Decabromodiphenyl Ether and accompanying Quickview have also been added to the IRIS Data...

258

Synthesis of Tetraazacrown Ethers Containing Two 8-Hydroxyquinoline Side Arms.  

National Technical Information Service (NTIS)

Four new tetraazacrown ethers containing two 8-hydroxyquinoline side arms were prepared first by reductive amination of 8-acetoxyquinolin-2-carbaldehyde with the appropriate tetraazacrown ether containing two microring NH functions. The resulting bis(8-ac...

Z. Yang J. S. Bradshaw P. B. Savage K. E. Krakowiak R. M. Izatt

1999-01-01

259

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

260

Vinyl ethers containing an epoxy group. XVI. Reaction of glycidol vinyloxyethyl ether with acetals  

SciTech Connect

In order to obtain branched acetals with epoxide groups (prospective monomers and intermediates) the authors investigated the reaction of acetaldehyde diethyl and di(1,1,3-trihydrotetrafluoropropyl) acetals with glycidol vinyloxyethyl ether. The addition of acetals to vinyl epoxy ethers was realized, and the first representative of compounds of this type, i.e., 9-glycidyloxy-6-ethoxy-4-methyl-3,7-dioxanonane, was obtained. It was also impossible to add a fluoroacetal to butyl vinyl ether (0.08-1.00 wt. % of catalyst CF/sub 3/COOH, BF/sub 3//times/ OEt/sub 2/, 20-80/degree/C, 0.5-3 h).

Nedolya, N.A.; Khil'ko, M.Ya.; Trofimov, B.A.; Sigalov, M.V.

1988-10-10

261

Radiation-Induced Polymerization of a Series of Vinyl Ethers  

Microsoft Academic Search

The radiation-induced polymerization of methyl, ethyl, isobutyl, isopropyl, and tert-butyl vinyl ethers was studied under super-dry conditions. Methyl vinyl ether did not polymerize at measurable rates; ethyl vinyl ether polymerized readily but with a dose rate dependence of the rate of only 0.3. The other ethers polymerized with a square-root dependence of the rate on the dose rate. Good agreement

A. M. Goineau; J. Kohler; V. Stannett

1977-01-01

262

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

263

Ether, the Theory of Relativity and Quantum Physics  

Microsoft Academic Search

\\u000a In this paper we revisit some of the reasons given by Einstein that resulted in his change of mind about the ether from denying\\u000a to defending its existence. The ether proposed by Einstein we call Einstein’s new ether. We consider the potential use of\\u000a Einstein’s new ether in quantum mechanics. The standard model of elementary particles reveals the existence of

Eduardo V. Flores

264

Persubstituted p-benzoquinone monoxime alkyl ethers and their molecular structure  

NASA Astrophysics Data System (ADS)

Theoretical and experimental approaches were applied for the investigation of the reactivity of persubstituted 4-nitrosophenols in the reaction with alkyl iodides, in particular the potassium salt of 2,6-di(alkoxycarbonyl)-3,5-dimethyl-4-nitrosophenol. Hartre-Fock calculations showed that the anion negative charge was located mostly on the oxygen of hydroxyl group, while estimation of the total energy of the alkylated products pointed out the benefit of alkylation on the oxygen atom of the nitroso group yielding p-benzoquinone monoxime alkyl ethers. Methylation and ethylation of persubstituted nitrosophenols were carried out. The products obtained were investigated using X-ray diffraction, 1? NMR spectroscopy and mass spectrometry. The crystal structure of the methyl ether of 2,6-di(alkoxycarbonyl)-3,5-dimethyl-1,4-benzoquinone-1-oxime (?15H19NO6) (I) was determined by the X-ray powder diffraction technique. The unit cell parameters were: a = 7.3322(6) Å, b = 10.5039(12) Å, c = 21.1520(20) Å, ? = 93.742(6)°, V = 1625.58(2) Å3Z = 4, Sp.Gr. P21/c. The structure modeling was made in direct space by the Monte-Carlo approach using rigid and soft restrictions. The structure refinement was completed by the Rietveld method. It was established that the alkylation occurred on the oxygen atom of the nitroso group. The molecules (I) in the crystal structure were packed in columns along the axis a with pairwise convergence in a column up to the distance of 3.63 Å due to a 180° turn of every second molecule around the column axis. In the molecular structure the methyloxime group was oriented in the benzene plane and had ?-conjugation with the ring. The ethoxycarbonyl groups were turned nearly perpendicular to the ring. Other compounds obtained had the structure of the alkyl ethers of 1.4-benzoquinone-1-oxime, which was proved by 1? NMR spectroscopy and mass-spectrometry.

Slaschinin, D. G.; Alemasov, Y. A.; Ilushkin, D. I.; Sokolenko, W. A.; Tovbis, M. S.; Kirik, S. D.

2012-05-01

265

Dimethyl 2,6-dimethyl-4-(2-nitro-phen-yl)pyridine-3,5-dicarboxyl-ate  

PubMed Central

The title compound, C17H16N2O6, is a decomposition product of the hypertension drug nifedipine [systematic name: dimethyl 2,6-dimethyl-4-(2-nitro­phen­yl)-1,4-dihydro­pyridine-3,5-dicarboxyl­ate]. The dihedral angle between the nitro­sophenyl ring and the pyridine ring is 67.1?(5)°.

Zheng, Juanjuan; Wang, Xueyuan; Pang, Dongying; Sun, Yan; Su, Wei

2011-01-01

266

Observation of a large negative temperature dependence for rate coefficients of reactions of OH with oxygenated volatile organic compounds studied at 86-112 K.  

PubMed

The rate coefficients (k) for reactions of OH with acetone, methyl ethyl ketone (MEK) and dimethyl ether (DME) have been measured in the temperature range 86-112 K using a pulsed Laval nozzle apparatus. Large increases in k at lower temperatures were observed, with k(86K)/k(295K) = 334 for acetone, and k(93K)/k(295K) = 72 and 3, for MEK and DME respectively. A mechanism involving the formation of a hydrogen bonded complex prior to an overall barrier on the potential energy surface is proposed to explain this behaviour. PMID:20859585

Shannon, Robin J; Taylor, Sally; Goddard, Andrew; Blitz, Mark A; Heard, Dwayne E

2010-11-01

267

Subchronic Dermal Exposure Study of Diethylene Glycol Monomethyl Ether and Ethylene Glycol Monomethyl Ether in the Male Guinea Pig.  

National Technical Information Service (NTIS)

Diethylene glycol monomethyl ether (DEGME) has been selected as a replacement anti-icing additive for ethylene glycol monomethly ether (EGME) in Navy jet aircraft fuel. This experiment was performed to determine whether DEGME produced similar toxicity to ...

D. W. Hobson A. P. D'Addario R. H. Bruner D. E. Uddin

1986-01-01

268

Copolymerization of vinyl chloroacetate with vinyl ethers and with styrene  

Microsoft Academic Search

1.Vinyl chloroacetate was synthesized by the method of indirect vinylation.2.Copolymers of vinyl chloroacetate with vinyl ethers (ethyl vinyl, butyl vinyl, and phenyl vinyl ethers) were synthesized. In some cases the content of vinyl ether units in these copolymers attained 80–90 moles percent.3.Copolymers of vinyl chloroacetate with styrene were synthesized.

M. F. Shostakovskii; A. M. Khomutov; A. P. Alimov

1963-01-01

269

The Conformational Analysis of 14-Membered Macrocyclic Ethers  

Microsoft Academic Search

The conformational analysis of a series of 14-membered macrocyclic ethers possessing a variety of methyl substitution patterns was performed using both NMR spectroscopy and molecular mechanics calculations. Low temperature DNMR spectra of the macrocyclic ethers were interpreted using van der Waals steric compression and anisotropic shielding effects. The macrocyclic ether transition state energies were determined from the DNMR spectra to

Dean S. Clyne; Larry Weiler

2000-01-01

270

A Local-Ether Model of Propagation of Electromagnetic Wave  

Microsoft Academic Search

The null result in the famous Michelson-Morley experiment is reinterpreted after proposing the local-ether model of wave propagation. It is postulated that, as in an obsolete theory, electromagnetic wave propagates via a medium called ether. However, the ether is not universal. It is supposed that the region under sufficient influence of the gravity due to the Earth or another celestial

Ching-Chuan Su

2000-01-01

271

Synthesis and characterization of new thermally stable poly(ether-imide)s derived from 4-aryl-2,6-bis[4-(3-nitrophthalimido)phenyl] pyridines  

Microsoft Academic Search

A series of thermally stable poly(ether-imide)s (PEI1–16) bearing bulky aryl pendant groups were synthesized by nitro-displacement condensation of a new series of dinitrobisimide monomers, namely 4-aryl-2,6-bis[4-(3-nitrophthalimido)phenyl]pyridines (DNBI1–4), with commercially available aromatic diols (DO1–4). These dinitrobisimides were prepared from the reaction of 4-aryl-2,6-bis(4-aminophenyl)pyridines (DA1–4) and 3-nitrophthalic anhydride in N,N-dimethyl acetamide. A model compound was synthesized by reaction of DNBI1 with phenol

Bahman Tamami; Gholam Ali Koohmareh

2007-01-01

272

Zirconium phosphate sulfonated poly (fluorinated arylene ether)s composite membranes for PEMFCs at 100–140 °C  

Microsoft Academic Search

Organic–inorganic hybrid composite membranes have been prepared and evaluated for polymer electrolyte membrane fuel cells (PEMFCs) at 100–140°C. A series of synthesized poly (fluorinated arylene ether)s was sulfonated by fuming sulfuric acid (20% SO3). The zirconium phosphate composite membrane was prepared by soaking the sulfonated poly (fluorinated arylene ether)s stepwise in 1M zirconyl chloride solution and 1M phosphoric acid solution.

Myung Heui Woo; Ohdeok Kwon; Sung Ho Choi; Ming Zi Hong; Hyung-Wook Ha; Keon Kim

2006-01-01

273

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

274

Nonequivalence of ether theories and special relativity  

Microsoft Academic Search

The role played by clock synchronization procedures for coordinate transformations which account for time dilation and length contraction is discussed. Special relativity is here compared with the ether theory based on the Tangherlini transformations. These transformations are shown to be theoretically distinguishable from the Lorentz ones by means of an internal synchronization procedure which makes use of rods kept in

Gianfranco Spavieri

1986-01-01

275

Limonene ethers from tire pyrolysis oil  

Microsoft Academic Search

The marketability of tire pyrolysis oil low is due to several demeritorious factors such as extreme odour and a high aromatic content. In order to enhance the marketability, we explored the production of fragrant oil from tire oil. In Part I of this study we reported the feasibility of reacting limonene-enriched tire oil with methanol to produce limonene ethers in

Maria Stanciulescu; Michio Ikura

2007-01-01

276

Orphan enzymes in ether lipid metabolism  

PubMed Central

Ether lipids are an emerging class of lipids which have so far not been investigated and understood in every detail. They have important roles as membrane components of e.g. lens, brain and testis, and as mediators such as platelet-activating factor. The metabolic enzymes for biosynthesis and degradation have been investigated to some extent. As most involved enzymes are integral membrane proteins they are tricky to handle in biochemical protocols. The sequence of some ether lipid metabolising enzymes has only recently been reported and other sequences still remain obscure. Defined enzymes without assigned sequence are known as orphan enzymes. One of these enzymes with uncharacterised sequence is plasmanylethanolamine desaturase, a key enzyme for the biosynthesis of one of the most abundant phospholipids in our body, the plasmalogens. This review aims to briefly summarise known functions of ether lipids, give an overview on their metabolism including the most prominent members, platelet-activating factor and the plasmalogens. A special focus is set on the description of orphan enzymes in ether lipid metabolism and on the successful strategies how four previous orphans have recently been assigned a sequence. Only one of these four was characterised by classical protein purification and sequencing, whereas the other three required alternative strategies such as bioinformatic candidate gene selection and recombinant expression or development of an inhibitor and multidimensional metabolic profiling.

Watschinger, Katrin; Werner, Ernst R.

2013-01-01

277

Limonene ethers from tire pyrolysis oil  

Microsoft Academic Search

Tire pyrolysis oil was produced by EnerVision Inc., Halifax, Canada using the continuous ablative reactor (CAR) system. The tire oil was separated by distillation into several fractions. Naphtha and limonene enriched naphtha were reacted with methanol over different catalysts. Batch experiments were carried out to separate limonene as methyl limonene ethers.Whole tire pyrolysis oil was distilled and the resulting distillates

Maria Stanciulescu; Michio Ikura

2006-01-01

278

"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

279

Ether drift experiments and electromagnetic momentum  

NASA Astrophysics Data System (ADS)

Propagation of Aharonov-Bohm matter waves and light waves in moving media is characterized by the interaction electromagnetic momentum. Thus, recent models of light propagation in moving rarefied media justify and call for an optical experiment of the Mascart-Jamin type, capable of testing the modern interpretations of ether drift experiments.

Spavieri, G.; Guerra, V.; de Abreu, R.; Gillies, G. T.

2008-05-01

280

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

281

Development of Sulfonated Poly(ether-ether ketone)s for PEMFC and DMFC  

NASA Astrophysics Data System (ADS)

During the last two decades, extensive efforts have been made to develop alternative hydrocarbon-based polymer electrolyte membranes to overcome the drawbacks of the current widely used perfluorosulfonic acid Nafion. This chapter presents an overview of the synthesis, chemical properties, and polymer electrolyte fuel cell applications of new proton-conducting polymer electrolyte membranes based on sulfonated poly(arylene ether ether ketone) polymers and copolymers.

Kim, Dae Sik; Guiver, Michael D.

282

Sulfonated poly(ether ether ketone) membranes for direct methanol fuel cell  

Microsoft Academic Search

Sulfonated poly(ether ether ketone) (SPEEK) membranes with various degrees of sulfonation (DS) were prepared. Their proton conductivity and methanol permeability as a function of temperature were investigated. It was found that the proton conductivity of SPEEK membranes exceeded 10?2S\\/cm above 80°C, which is close to that of Nafion® 115 membrane under the same condition. The methanol permeability of SPEEK membranes

Lei Li; Jun Zhang; Yuxin Wang

2003-01-01

283

Proton conducting membranes based on cross-linked sulfonated poly(ether ether ketone) (SPEEK)  

Microsoft Academic Search

A new method for the preparation of proton exchange membranes (PEMs), based on cross-linked sulfonated poly(ether ether ketones) is reported. The cross-linking involves thermally activated bridging of the polymer chains with polyatomic alcohols, which makes the polymer mechanically stronger and reduces its swelling by water. Although the cross-linking occurs through the sulfonic acid group, a major portion of acid functions

Serguei D Mikhailenko; Keping Wang; Serge Kaliaguine; Peixiang Xing; Gilles P Robertson; Michael D Guiver

2004-01-01

284

Microvalves for Natural-Gas Analysis With Poly Ether Ether Ketone Membranes  

Microsoft Academic Search

We present the use of poly ether ether ketone (PEEK) as a membrane material for a new type of gas microvalve, which is suitable for the harsh environments of natural gas. The design, fabrication, and experimental characterization of the PEEK-based microvalves are presented first, revealing leakage levels of less than 230 nL·min-1 under nitrogen and helium. Then, the main mechanical

Kinda Nachef; Tarik Bourouina; Frédéric Marty; Kamran Danaie; Bertrand Bourlon; Eric Donzier

2010-01-01

285

Novel poly(arylene ether)s containing multi-substituted pentaphenylene moiety  

Microsoft Academic Search

Three novel 2-trifluoromethyl-activated bisfluoro monomers have been synthesized successfully using a Suzuki-coupling reaction of 4-fluoro-3-trifluoromethyl phenyl boronic acid with 4,4?-dibromo-p-terphenyls with varied phenyl substitution on the middle phenylene ring. Three monomers were converted to a series of phenyl substituted poly(arylene ether)s by nucleophilic displacement of the fluorine atoms on the terminal benzene ring with several bisphenols. The polymers obtained by

B. R. Liaw; W. Y. Huang; P. T. Huang; M. Y. Chang; Y. K. Han

2007-01-01

286

Novel high T[sub g] high-strength poly(aryl ether)s  

Microsoft Academic Search

A novel 2-perfluoroalkyl-activated bisfluoro monomer has been synthesized successfully using a Pd(0)-catalyzed cross-coupling reaction of 4-fluoro-3-trifluoromethyl phenyl boronic acid with 4,4[prime]-dibromodiphenylbenzene. This monomer was converted to novel poly(aryl ether)s by nucleophilic displacement of the fluorine atoms on the benzene ring with several bisphenols. The products obtained by displacement of the fluorine atoms exhibit weight average molar masses up to 1.06

S. Banerjee; G. Maier

1999-01-01

287

Novel high T{sub g} high-strength poly(aryl ether)s  

Microsoft Academic Search

A novel 2-perfluoroalkyl-activated bisfluoro monomer has been synthesized successfully using a Pd(0)-catalyzed cross-coupling reaction of 4-fluoro-3-trifluoromethyl phenyl boronic acid with 4,4â²-dibromodiphenylbenzene. This monomer was converted to novel poly(aryl ether)s by nucleophilic displacement of the fluorine atoms on the benzene ring with several bisphenols. The products obtained by displacement of the fluorine atoms exhibit weight average molar masses up to 1.06

S. Banerjee; G. Maier

1999-01-01

288

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

289

Oncology nurses' experience of dimethyl sulfoxide odor.  

PubMed

This article presents findings of an exploratory descriptive study on the effects of dimethyl sulfoxide (DMSO) odor in an oncology unit. The nursing staff, who had reported their concerns about the unpleasant odor emitted from patients undergoing peripheral stem cell transplantation, initiated the study. A literature review revealed some evidence of the possible ill effects on staff caring for patients having DMSO treatment, but many questions remain unanswered such as what staff experience in dealing with DMSO odor and whether nursing care is affected in any way? Data were collected through interviews with 22 oncology nurses who all had experienced direct and indirect exposure to DMSO odor. Of the 22 nurses interviewed, 20 reported that they found DMSO odor unpleasant and reported experiencing physical symptoms such as headaches and gastrointestinal reactions. The study also revealed a situation in which nurses described odor avoidance and distancing strategies that potentially compromised the nurse-patient relationship. PMID:10763285

Prior, D; Mitchell, A; Nebauer, M; Smith, M

2000-04-01

290

Synthesis and Properties of Copolymers of Poly(ether ketone ketone) and Poly(ether ether ketone ketone) Containing Naphthalene Moieties and Pendant Cyano Groups  

Microsoft Academic Search

A new monomer containing naphthalene, 2,6-bis(? -naphthoxy)benzonitrile (BNOBN) was synthesized by reaction of ? -naphthol with 2,6-difluorobenzonitrile in N-methyl-2-pyrrolidone (NMP) in the presence of KOH and K 2CO3. Novel copolymers of poly(ether ketone ketone) and poly(ether ether ketone ketone) containing naphthalene moieties and pendant cyano groups were prepared by electrophilic Friedel—Crafts solution copolycondensation of terephthaloyl chloride (TPC) with varying mole

Mingzhong cai; Qin Xi; Nengwen Ding; Caisheng Song

2010-01-01

291

Thermochemical production of liquid fuels from biomass: Thermo-economic modeling, process design and process integration analysis  

Microsoft Academic Search

A detailed thermo-economic model combining thermodynamics with economic analysis and considering different technological alternatives for the thermochemical production of liquid fuels from lignocellulosic biomass is presented. Energetic and economic models for the production of Fischer–Tropsch fuel (FT), methanol (MeOH) and dimethyl ether (DME) by means of biomass drying with steam or flue gas, directly or indirectly heated fluidized bed or

Laurence Tock; Martin Gassner; François Maréchal

2010-01-01

292

IGNITION IMPROVEMENT OF LEAN NATURAL GAS MIXTURES  

Microsoft Academic Search

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,

Jason M. Keith

2005-01-01

293

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

294

Experimental results from a microdot detector overcoated with a semiconducting layer  

Microsoft Academic Search

A Microdot (MDOT) detector has been overcoated with a boron-doped amorphous silicon carbide semiconductive layer. The stable operation of the device in mixtures of argon, neon and helium with di-methyl ether (DME) at high gains and at high counting rates is shown. Radiation damage tests give a lifetime of over 120mC\\/cm using a gas system with plastic gas pipes.

S. F. Biagi; D. Duxbury; E. Gabathuler

1998-01-01

295

Excess enthalpies of ternary mixtures consisting of a normal alkane, methyl tert-butyl ether, and tert-amyl methyl ether  

SciTech Connect

The thermodynamic properties of hydrocarbon + ether mixtures are of interest in view of the use of ethers as oxygenating agents in gasoline technology. Excess molar enthalpies, measured at 298.15 K in a flow microcalorimeter, are reported for the two ternary systems heptane + methyl tert-butyl ether + tert-amyl methyl ether and decane + methyl tert-butyl ether + tert-amyl methyl ether. Smooth representations of the results and analyses in terms of the Flory theory are presented.

Tong, Z.; Benson, G.C.; Wang, L.L.; Lu, B.C.Y. [Univ. of Ottawa, Ontario (Canada). Dept. of Chemical Engineering] [Univ. of Ottawa, Ontario (Canada). Dept. of Chemical Engineering

1996-07-01

296

Melanin: The Effects of Dimethyl Sulfoxide on the Spectral Properties.  

National Technical Information Service (NTIS)

Investigation of the spectroscopic properties of melanin dissolved in dimethyl sulfoxide (DMSO) is one part of a more expansive study of melanin. The absorption spectrum of melanin dissolved in DMSO differed from the spectrum in acidic or neutral solution...

D. L. Bolton D. L. Lund R. D. O'Connor S. T. Schuschereba T. M. Cooper

1986-01-01

297

Adsorption and Decomposition of Dimethyl Methylphosphonate on Platinum(111),  

National Technical Information Service (NTIS)

The interaction of dimethyl methylphosphonate (DMMP) with platinum (111) was studied with high-resolution electron energy loss spectroscopy (HREELS), positive and negative static secondary ion mass spectrometry (SSIMS), temperature-programmed desorption (...

M. A. Henderson J. M. White

1988-01-01

298

Excimer Fluorescence from 3,3'-Dimethyl-9-Ethylthiacarbocyanine Iodide.  

National Technical Information Service (NTIS)

Excimer fluorescence has been observed from 3,3'-dimethyl-9-ethylthiacarbocyanine iodide in alcoholic solvents. The excimer probably has a sandwich configuration and is composed of two all-trans isomers. (Author)

J. T. Knudtson E. M. Eyring

1974-01-01

299

Dimethyl Sulfide-Borane. A Convenient Hydroborating Agent.  

National Technical Information Service (NTIS)

Dimethyl sulfide-borane provides a means of handling diborane as a room-temperature storable, liquid with most of its hazardous nature tamed, yet retaining sufficient reactivity for most hydroboration and reduction applications in organic chemistry. Tabul...

H. R. Crissman L. M. Braun M. Opperman R. A. Braun R. M. Adams

1970-01-01

300

Comparative studies on the metabolism and mutagenicity of vinyl ethers.  

PubMed

4-Nitrophenyl vinyl ether (1), umbelliferyl vinyl ether (2), 4-cyanophenyl vinyl ether (3), and 4-acetylphenyl vinyl ether (4) were mutagenic toward Salmonella typhimurium TA100 and TA100NR in the presence of the hepatic 9000 x g supernatant fraction fortified with a reduced nicotinamide adenine dinucleotide phosphate generating system (S9mix), but no significant mutagenicity of 4-chlorophenyl vinyl ether (5), phenyl vinyl ether (6), n-butyl vinyl ether (7), and ethyl vinyl ether (8) was found. The epoxides of 1-4 were highly mutagenic toward the bacteria without the S9mix. Also, epoxides of 5 and 6 showed relatively weak mutagenicity. Studies on the metabolism of 1 showed that the epoxide (1a) formed from 1 by microsomes behaved as a labile intermediate in the incubation mixture. Untreated rat hepatic microsomes accumulated 1a and induced mutagenicity of 1 most effectively among the activation systems used. Mutagenic activities of vinyl ethers in the presence of the S9mix were correlated with stabilities of their epoxides. From these results, it is suggested that the critical factor for the mutagenicity of vinyl ethers is the formation and stability of epoxide intermediate in the biological system. PMID:2674402

Sone, T; Isobe, M; Takabatake, E

1989-06-01

301

Unimolecular reactions of ionized methyl butenyl ethers  

NASA Astrophysics Data System (ADS)

The reactions of metastable C4H7OCH·+3 radical cations generated by ionization of methyl ethers derived from stable butenols have been investigated by means of 2H- and 13C-labelling experiments, kinetic energy release measurements and analysis of collision-induced dissociation spectra. The reactions shown by the ionized allylic ethers, CH3CH=CHCH2OCH·+3 and CH2=C(CH3)CH2OCH·+3, are almost identical, especially at low internal energy. However, the behaviour of these isomers of C4H7OCH·+3 differs subtly from that of CH2=CHCH(CH3)OCH·+3. All these species undergo mainly loss of a methyl radical is slow dissociations, usually with formation of CH2=CHCH=O+CH3 as the product ion. The specificity of hydrogen atom selection shown in methyl radical elimination from 2H-labelled analogues of CH2=CHCH(CH3)OCH·+3 is distinct from that displayed by the two other allylic isomers of C4H7OCH·+3. In contrast to the three ionized allylic ethers, metastable CH2=CHCH2CH2OCH·+3 undergoes a sizeable amount of two other reactions -- expulsion of a hydrogen atom or a formaldehyde molecule -- in addition to undergoing methyl radical elimination. The specificity of methyl radical loss from this ion is different from those found for the analogous fragmentation of the ionized allylic ethers; moreover, the resultant C4H7O+ product ion is mainly +, rather than CH2=CHCH=O+CH3.

Bowen, Richard D.; Wright, Andrew D.; Colburn, Alex W.; Derrick, Peter J.

1992-08-01

302

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...

303

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

304

Chemistry and adhesive properties of poly(arylene ether)s containing heterocyclic units  

NASA Technical Reports Server (NTRS)

Novel poly(arylene ether)s containing heterocyclic units were prepared, characterized, and evaluated as adhesives and composite matrices. The polymers were prepared by reacting a heterocyclic bisphenol with an activated aromatic dihalide in a polar aprotic solvent, using potassium carbonate. The polymerizations were generally carried out in N,N-dimethylacetamide at 155 C. In some cases, where the polymers were semicrystalline, higher temperatures and thus higher boiling solvents were necessary to keep the polymers in solution. Heterocyclic rings incorporated into the poly(arylene ether) backbone include phenylquinoxaline, phenylimidazole, benzimidazole, benzoxazole, 1,3,4-oxadiazole, and 1,2,4-triazole. The polymers were characterized by differential scanning calorimetry, solution viscosity, X-ray diffraction, thin film, and adhesive and (in some cases) composite properties. The glass transition temperatures, crystalline melt temperature, solubility, and mechanical properties varied depending upon the heterocyclic ring. The chemistry and properties of these materials are discussed.

Connell, John W.

1991-01-01

305

Dimethyl carbonate production for fuel additives  

SciTech Connect

We have taken note of the transesterification reaction as a highly safe process of dimethyl carbonate (DMC) production for fuel additives. The reaction proceeds under the low corrosiveness and in the relatively mild condition. We have aimed to use an inorganic solid catalyst for this process. The inorganic solid catalyst is thermally stable and can be used in the large-scale fixed bed reactors without a catalyst separation unit. Through the transesterification of ethylene carbonate (EG) with methanol, DMC and ethylene glycol (EG) are co-generated as the products. EG is one of the bulk chemicals produced in the large scale plant comparable to one for the fuel additives. The market balance is important in the coproduction process. On the assumption that the amount of the co-production meets the market balance, the coproduction of DMC and EG is commercially viable. If we can control the amount of the EG coproduction in this process, it makes the process more flexible in the commercial production. Accordingly we have proposed a conceptual process scheme to control the amount of the EG coproduction. In this symposium, the inorganic solid catalyst system applying to the transesterification process and the conceptual process scheme how to control the amount of co-product will be discussed.

Okada, Y.; Kondo, T.; Asaoka, S. [Chiyoda Corp., Yokohama (Japan)

1996-12-31

306

Transport properties of dimethyl sulfoxide aqueous solutions  

NASA Astrophysics Data System (ADS)

The nonideal behavior of the transport properties of water-dimethyl sulfoxide (DMSO) mixtures has been studied through equilibrium and nonequilibrium molecular dynamic simulations. The shear viscosity and thermal conductivity of the mixture has been analyzed and compared with available experimental data at ambient conditions. The enhancement of shear viscosity at molar fractions xW=0.65 of water has been quantitatively reproduced in our simulations. In agreement with this fact, we have found an increase in the rigidity of the system reflected by an increase in the decay time of the survival probability of the H bonds. In addition, we compute the tetrahedral order parameter of water molecules in the solution at different molar fractions. This parameter indicates a reduction in the local tetrahedral order of water when the solute concentration is increased, followed by a clear minimum at the equimolar concentration near the locus of the maximum density of the mixture, probably due to the formation of water-DMSO complexes. We have obtained the thermal conductivity of the mixture for the first time. This property also presents a peculiar minimum at xW=0.4, precisely in the region of the minimum of the order parameter. However, no experimental confirmation of our results is available.

Nieto-Draghi, Carlos; Bonet Ávalos, Josep; Rousseau, Bernard

2003-09-01

307

Dimethyl sulfide over the western Atlantic Ocean  

NASA Astrophysics Data System (ADS)

Dimethyl sulfide and anthropogenic pollutants were measured over the western Atlantic Ocean during January and February 1986, 50 to 150 km east of Boston, MA and in the vicinity of Bermuda in June 1986. The highest DMS concentration measured in the vicinity of Boston was 18 pptv; all other values within the mixed layer (ML) were between 0.5 and 12 pptv. The free troposphere (FT) values were 0.5-5.0 pptv. Sea to air fluxes were estimated at 36 to 66 ng m-2 min-1. FT values measured near Bermuda were 1-17 pptv, and most values were <10 pptv. The Bermuda ML values (35-195 pptv) were as much as 10 times greater than those found near Boston. A steep vertical gradient was observed within the ML in the mid-ocean measurements, indicating that DMS removal rates were faster than the ML mixing times. Several variables may be of consequence in the differences observed between the Boston and Bermuda measurements; the most important of these appear to be the air mass travel time over the ocean and the sea surface temperature.

Van Valin, C. C.; Berresheim, H.; Andreae, M. O.; Luria, M.

1987-07-01

308

Syntheses and crystal structures of lithium derivatives of diphosphanes R 2P–P(SiMe 3)Li · 3L, R = Ph, i Pr and i Pr 2N, L = THF or DME  

Microsoft Academic Search

The reactions of R2P–P(SiMe3)2 (R=Ph, iPr and iPr2N) with BuLi in THF or DME solution lead to ion-contacted lithium derivatives R2P–P(SiMe3)Li·3THF (R=iPr, iPr2N) with tetrahedrally surrounded Li atoms and to the solvent-separated ionic [Li·3DME]+[Ph2P–PSiMe3]? with an octahedrally surrounded Li atom as confirmed by X-ray crystal structure analysis. The reaction of BuLi with Ph2P–P(SiMe3)2 is accompanied with a significant side-reaction leading

Wioleta Doma?ska-Babul; Katarzyna Baranowska; Rafa? Grubba; Eberhard Matern; Jerzy Pikies

2007-01-01

309

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

310

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

311

High octane ethers from synthesis gas-derived alcohols  

Microsoft Academic Search

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

K. Klier; R. G. Herman; R. D. Bastian; S. DeTavernier

1991-01-01

312

High octane ethers from synthesis gas-derived alcohols  

Microsoft Academic Search

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-l-propanol (isobutanol). The overall scheme involves gasification of coal, purification and shifting of the synthesis gas, higher alcohol synthesis, and

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

1992-01-01

313

Inactivation of MXR1 Abolishes Formation of Dimethyl Sulfide from Dimethyl Sulfoxide in Saccharomyces cerevisiae  

PubMed Central

Dimethyl sulfide (DMS) is a sulfur compound of importance for the organoleptic properties of beer, especially some lager beers. Synthesis of DMS during beer production occurs partly during wort production and partly during fermentation. Methionine sulfoxide reductases are the enzymes responsible for reduction of oxidized cellular methionines. These enzymes have been suggested to be able to reduce dimethyl sulfoxide (DMSO) as well, with DMS as the product. A gene for an enzymatic activity leading to methionine sulfoxide reduction in Saccharomyces yeast was recently identified. We confirmed that the Saccharomyces cerevisiae open reading frame YER042w appears to encode a methionine sulfoxide reductase, and propose the name MXR1 for the gene. We found that Mxr1p catalyzes reduction of DMSO to DMS and that an mxr1 disruption mutant cannot reduce DMSO to DMS. Mutant strains appear to have unchanged fitness under several laboratory conditions, and in this paper I hypothesize that disruption of MXR1 in brewing yeasts would neutralize the contribution of the yeast to the DMS content in beer.

Hansen, J?rgen

1999-01-01

314

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

315

Functionalized poly(arylene ethers) as toughness modifiers for bismaleimides  

NASA Technical Reports Server (NTRS)

A family of novel, low molecular weight functionalized poly(arylene ether) resins has been investigated to ascertain its members' toughness-imparting contribution to neat bismaleimide (BMI) resin and BMI-matrix laminate composite properties. Attention is given to the contribution of the reactive poly(arylene ether)'s backbone chemistry to fracture toughness, as well as to the comparative influence of high and low molecular weight reactive poly(arylene ether) types on the modified BMI resin systems. The modified BMIs possess a polyphase morphology, with good adhesion between the thermoplastic nodules and the host thermoset systems.

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

1990-01-01

316

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

317

Synthesis and properties of novel H-bonded composite membranes from sulfonated poly(phthalazinone ether)s for PEMFC  

Microsoft Academic Search

In this work, sulfonated poly(phthalazinone ether)s (SPPENK, SPPESK and SPPBEK) were synthesized by direct aromatic nucleophilic polycondensation reaction. H-bonded composite membranes were prepared from SPPENK, SPPESK and SPPBEK, respectively, and polyetherimide (PEI). Both of compounds were dissolved in N-methylpyrrolidone (NMP), and tough membranes were obtained by casting from NMP solution with 9:1 mass ratio of sulfonated poly(phthalazinone ether)s\\/PEI. These H-bonded

Xiuling Zhu; Yongfang Liang; Haiyan Pan; Xigao Jian; Yaoxia Zhang

2008-01-01

318

Synthesis and Characterization of Copolymers of Poly(aryl ether ketone amide) and Poly(aryl ether ketone ketone)  

Microsoft Academic Search

A new monomer containing amide linkages, N,N?-bis(4-phenoxybenzoyl)- p-phenylenediamine (BPBPPD), was prepared by condensation of p-phenylenediamine with 4-phenoxybenzoyl chloride in N,N-dimethylacetamide (DMAc). A series of novel copolymers of poly(ether ketone amide) (PEKA) and poly(ether ketone ketone) (PEKK) were synthesized by electrophilic Friedel—Crafts solution copolycondensation of isophthaloyl chloride (IPC) with a mixture of BPBPPD and diphenyl ether (DPE), over a wide range

Meihua Zhu; Yongfeng Sun; Mingzhong Cai

2010-01-01

319

Syntheses and characterizations of side-chain liquid crystalline poly(glycidyl ether)s with biphenyl mesogenic group  

Microsoft Academic Search

Summary  \\u000a Four three-armed poly(glycidyl ether)s with biphenyl mesogenic group and various lengths of spacer, new side-chain liquid\\u000a crystalline polymers, were synthesized by cationic ring-opening polymerization of the corresponding monomers in the presence\\u000a of 2,2-dihydroxymethylbutanol and BF3·OEt2 as initiator. The structures of the obtained poly(glycidyl ether)s were verified by 1H and 13C NMR spectroscopy, and their liquid crystalline behaviors were studied

Caiyuan Pan; Bo Yang

1999-01-01

320

The failure of poly (ether ether ketone) in high speed contacts  

NASA Astrophysics Data System (ADS)

The paper describes an experimental study, with an associated analysis incorporating supplementary data, of the anti-boundary lubricating action of an alkane-aliphatic carboxylic acid lubricant system in a poly (ether ether ketone)-mild steel contact. The experiments involve progressively increasing the load in a contact formed between a polymer plate and a rotating steel shaft and estimating the frictional work dissipated. Scuffing is identified when a rapid increase in frictional work is noted at a characteristic normal load. It is shown that the additive induces premature scuffing. Subsidiary data is provided using Raman spectroscopy and hardness probes, and confirms that certain additives such as decanoic acid and dodecylamine will induce surface plasticization in poly (ether ether ketone). The trends in the frictional data have been interpreted using the adhesive model of friction in conjunction with temperature-dependent interfacial theology and bulk mechanical property data. It is proposed that the scuffing process is induced prematurely as a consequence of excessive additive-induced subsurface plasticization. Restricted surface plasticization in this system provides an enhanced self-lubricating capacity.

Briscoe, B. J.; Stuart, B. H.; Sebastian, S.; Tweedale, P. J.

1993-04-01

321

Poly(arylene ether)s containing superacid groups as proton exchange membranes.  

PubMed

A series of poly(arylene ether)s containing pendant superacid groups on fluorenyl groups were synthesized and their properties were investigated for fuel cell applications. Poly(arylene ether)s containing iodo groups were synthesized by the polymerization of 2,7-diiodo-9,9-bis(4-hydroxyphenyl)fluorene with difluorinated compounds such as decafluorobiphenyl, bis(4-fluorophenyl)sulfone, and bis(4-fluorophenyl)ketone, under nucleophilic substitution conditions. The iodo groups on the fluorenyl groups were converted to perfluorosulfonic acid groups via the Ullmann coupling reaction. The degree of perfluorosulfonation was controlled to be up to 92%, which corresponds to an ion exchange capacity (IEC) of 1.52 meq/g. The ionomers yielded flexible, ductile membranes by solution casting. The ionomer membranes exhibited a characteristic hydrophilic/hydrophobic phase separation, with small interconnected hydrophilic clusters (2-3 nm), which is similar to that of the benchmark perfluorinated membrane (Nafion). The aromatic ionomers containing superacid groups showed much higher proton conductivities than those of the conventional sulfonated aromatic ionomers with similar main chain structures. Fuel cell performance with the superacidic ionomer membranes was also tested. PMID:20491452

Mikami, Takefumi; Miyatake, Kenji; Watanabe, Masahiro

2010-06-01

322

Novel high T{sub g} high-strength poly(aryl ether)s  

SciTech Connect

A novel 2-perfluoroalkyl-activated bisfluoro monomer has been synthesized successfully using a Pd(0)-catalyzed cross-coupling reaction of 4-fluoro-3-trifluoromethyl phenyl boronic acid with 4,4{prime}-dibromodiphenylbenzene. This monomer was converted to novel poly(aryl ether)s by nucleophilic displacement of the fluorine atoms on the benzene ring with several bisphenols. The products obtained by displacement of the fluorine atoms exhibit weight average molar masses up to 1.06 {times} 10{sup 5} g/mol in GPC. These poly(aryl ether)s showed outstanding thermooxidative stability up to 534 C for 5% weight loss in TGA under synthetic air and high glass transition temperatures (T{sub g}) even up to 300 C in DSC and DMTA. These polymers are soluble in a wide range of organic solvents, e.g., CHCl{sub 3}, THF, NMP, DMF, toluene, etc., and are insoluble in DMSO and acetone. Transparent thin films of these polymers cast from DMF exhibited tensile strengths up to 115 MPa, moduli up to 2.59 GPa, and elongations up to 120% depending on their exact repeating unit structures. These values are comparable to those of high performance thermoplastic materials such as PEEK or Ultem PEI.

Banerjee, S.; Maier, G. [Technische Univ. Muenchen, Garching (Germany). Lehrstuhl fuer Makromolekulare Stoffe] [Technische Univ. Muenchen, Garching (Germany). Lehrstuhl fuer Makromolekulare Stoffe

1999-08-01

323

Novel high T[sub g] high-strength poly(aryl ether)s  

SciTech Connect

A novel 2-perfluoroalkyl-activated bisfluoro monomer has been synthesized successfully using a Pd(0)-catalyzed cross-coupling reaction of 4-fluoro-3-trifluoromethyl phenyl boronic acid with 4,4[prime]-dibromodiphenylbenzene. This monomer was converted to novel poly(aryl ether)s by nucleophilic displacement of the fluorine atoms on the benzene ring with several bisphenols. The products obtained by displacement of the fluorine atoms exhibit weight average molar masses up to 1.06 [times] 10[sup 5] g/mol in GPC. These poly(aryl ether)s showed outstanding thermooxidative stability up to 534 C for 5% weight loss in TGA under synthetic air and high glass transition temperatures (T[sub g]) even up to 300 C in DSC and DMTA. These polymers are soluble in a wide range of organic solvents, e.g., CHCl[sub 3], THF, NMP, DMF, toluene, etc., and are insoluble in DMSO and acetone. Transparent thin films of these polymers cast from DMF exhibited tensile strengths up to 115 MPa, moduli up to 2.59 GPa, and elongations up to 120% depending on their exact repeating unit structures. These values are comparable to those of high performance thermoplastic materials such as PEEK or Ultem PEI.

Banerjee, S.; Maier, G. (Technische Univ. Muenchen, Garching (Germany). Lehrstuhl fuer Makromolekulare Stoffe)

1999-08-01

324

Brominated-chlorinated diphenyl ethers formed by thermolysis of polybrominated diphenyl ethers at low temperatures.  

PubMed

Polybrominated diphenyl ethers (PBDEs) are a group of brominated flame retardants (BFRs) used mainly as additives in different kinds of plastic material. Various PBDEs are found in all environmental compartments as well as in tissue and blood serum of animals and humans due to their persistence and tendency to bioaccumulate. Emission of PBDEs into the environment can occur during recycling of PBDE-containing plastic material or during their uncontrolled or insufficient combustion as e.g. in accidental fires or landfill fires. Under these circumstances, PBDEs can also function as precursor molecules for the formation of polybrominated dibenzodioxins (PBDDs) and dibenzofurans (PBDFs). In this study, we qualitatively investigated the reaction of two PBDE congeners, 2,2',4,4'-tetrabromo diphenyl ether (BDE 47) and 2,2',4,4',5,5'-hexabromo diphenyl ether (BDE 153), as well as hexabromobenzene (HBB), a flame retardant used in the past, when exposed to temperatures between 250 degrees C and 500 degrees C. The formed reaction products were analysed by high resolution gas chromatography-low resolution mass spectrometry (HRGC-LRMS). Among others brominated-chlorinated diphenyl ethers were formed by chlorodebromination of the PBDEs. In addition, thermolysis of BDE 47 and BDE 153 in the presence of tetrachloromethane as model substance for an organic chlorine source was studied. Thermal treatment of HBB resulted in the formation of brominated-chlorinated benzenes. PMID:16083771

Rupp, Silke; Metzger, Jörg W

2005-09-01

325

Structure Modification of Fluorocarbon Ether Bibenzoxazole Polymers to Improve Hydrolytic Stability.  

National Technical Information Service (NTIS)

Hydrolytically and thermooxidatively stable fluorocarbon ether bibenzoxazole (FEB) polymers were synthesized by the acetic acid-promoted polycyclocondensation of fluorocarbon ether bis (o-aminophenol) monomers with novel fluorocarbon ether dithioimidate e...

R. C. Evers G. J. Moore J. L. Burkett

1979-01-01

326

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

327

40 CFR 721.1580 - Disubstituted benzene ether, polymer with substituted phenol (generic).  

Code of Federal Regulations, 2010 CFR

... false Disubstituted benzene ether, polymer with substituted phenol (generic...1580 Disubstituted benzene ether, polymer with substituted phenol (generic...identified as disubstituted benzene ether, polymer with substituted phenol (PMN...

2010-07-01

328

40 CFR 721.10605 - Polyoxyalkylene ether, polymer with aliphatic diisocyanate, homopolymer, alkanol-blocked (generic).  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Polyoxyalkylene ether, polymer with aliphatic diisocyanate, homopolymer...721.10605 Polyoxyalkylene ether, polymer with aliphatic diisocyanate, homopolymer...generically as polyoxyalkylene ether, polymer with aliphatic diisocyanate,...

2013-07-01

329

40 CFR 721.10017 - Amine terminated bisphenol A diglycidyl ether polymer (generic).  

Code of Federal Regulations, 2010 CFR

...2010-07-01 false Amine terminated bisphenol A diglycidyl ether polymer (generic...Substances § 721.10017 Amine terminated bisphenol A diglycidyl ether polymer (generic...identified generically as amine terminated bisphenol A diglycidyl ether polymer...

2010-07-01

330

40 CFR 721.990 - 1,4-Benzedicarboxylic acid, dimethyl ester, polymer with 1,4 - butanediol, cyclized.  

Code of Federal Regulations, 2010 CFR

...4-Benzedicarboxylic acid, dimethyl ester, polymer with 1,4 - butanediol, cyclized...4-Benzedicarboxylic acid, dimethyl ester, polymer with 1,4 - butanediol, cyclized...4-benzedicarboxylic acid, dimethyl ester, polymer with 1,4 - butanediol,...

2010-07-01

331

Studies on haemin in dimethyl sulphoxide/water mixtures.  

PubMed Central

The nature of the complexes and equilibria shown by solutions of protohaemin in dimethyl sulphoxide/water mixtures and in the presence of acid and base were studied by u.v.-visible spectrophotometry. In neutral solutions containing from 40 to 100% dimethyl sulphoxide, haemin is present as a monomeric complex in which the Cl-ion is not coordinated. Only a single pH-dependent equilibrium pK12 is observed over the range 40-80% dimethylsulphoxide, corresponding to formation of the mu-oxo dimer. As the dimethyl sulphoxide content is lowered below 35%, so the single equilibrium (pK12) is replaced by two equilibria (pK1 and pK2); with solutions of 5 microM-haemin, pK1 decreases (from pK12 7.55 in 65% dimethyl sulphoxide to pK1 approx. 1.5 in 0.01% dimethyl sulphoxide), whereas pK2 hardly changes (from pK12 7.55 in 65% to pK2 approx. 7.5 in 0.01%).

Collier, G S; Pratt, J M; De Wet, C R; Tshabalala, C F

1979-01-01

332

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

333

Polyamideimides containing carbonyl and ether connecting groups  

NASA Technical Reports Server (NTRS)

Polyamidenimides were prepared from the reaction of trimellitic anhydride chloride with seven diamines containing carbonyl and ether groups between the aromatic rings. Several of these polyamideimides were semicrystalline as evidenced by wide-angle X-ray diffraction and differential scanning calorimetry. Glass transition temperatures ranged between 187 and 245 C, and crystalline transition temperatures ranged between 317 and 416 C. A series of copolyamideimides from a mixture of 1,3-bis(4-aminophenoxy 4-prime-benzoyl) benzene and 1,4-bis(4-aminophenoxy 4-prime-benzoyl)benzene were similarly prepared. These copolyamideimides were semicrystalline and formed tough, solvent resistant films with good tensile properties.

Havens, S. J.; Hergenrother, P. M.

1990-01-01

334

Fluorinated Poly(Phenylene Ether Ketones)  

NASA Technical Reports Server (NTRS)

Fluorinated poly(phenylene ether ketones) are colorless, transparent, low-dielectric-constant, highly thermally stable polymers. Particularly suitable for use as film and coating materials in electronic and thermal-control applications such as; passivant insulating coats and interlevel dielectrics in microelectronic circuits, or as protective transparent coats on solar cells or mirrors. Solubility and transparency of 12F-PEK along with its lower dielectric constant and other properties make it more useful as dielectric film and coating material in many applications.

St. Clair, Anne K.; Cassidy, Patrick E.; Tullos, Gordon L.

1994-01-01

335

Radiation-Induced Degradation of a Series of Poly(vinyl Ethers)  

Microsoft Academic Search

The degradative effects of ?-radiation on diethyl ether solutions of poly(alkyl vinyl ethers) under a variety of conditions were studied by polymer molecular weight measurements. Poly(methyl vinyl ether) (PMVE), poly(ethyl vinyl ether) (PEVE), poly(isopropyl vinyl ether) (PIPVE), and poly(isobutyl vinyl ether) (PIBVE) exhibited similar degradative behavior, with G(SC) values between 0.3 and 0.9 scissions\\/100 eV at 0°C. Chemically polymerized and

Y. Suzuki; J. M. Rooney; V. Stannett

1978-01-01

336

40 CFR 721.825 - Certain aromatic ether diamines.  

Code of Federal Regulations, 2010 CFR

...2009-07-01 2009-07-01 false Certain aromatic ether diamines. 721.825 Section 721.825 Protection of Environment...Chemical Substances § 721.825 Certain aromatic ether diamines. (a) Chemical substances and significant new uses...

2009-07-01

337

40 CFR 721.825 - Certain aromatic ether diamines.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 false Certain aromatic ether diamines. 721.825 Section 721.825 Protection of Environment...Chemical Substances § 721.825 Certain aromatic ether diamines. (a) Chemical substances and significant new uses...

2010-07-01

338

Conductometric Studies on Cation-Crown Ether Complexes: A Review  

Microsoft Academic Search

Crown ethers have proved to be unique cyclic molecules for molecular recognition of suitable substrates by hydrogen bonds, ionic interactions, and\\/or hydrophobic interactions. The study of interactions involved in complexation of different cations with crown ethers in mixtures of solvents is important for a better understanding of the mechanism of biological transport, molecular recognition, and other analytical applications. This fundamental

Francis A. Christy; Pranav S. Shrivastav

2011-01-01

339

Synthesis of the first perfluoro-spiro-bis-crown ethers  

SciTech Connect

Since the first perfluoro crown ethers were prepared by members of our research group, many new perfluoro crown ethers have been synthesized, and medical applications such as {sup 19}F NMR imaging and oxygen carrier applications as well as new chemistry associated with these compounds are currently under study. Perfluoro crown ethers do not form extremely stable complexes with metal cations because the basicities of perfluoro crown ethers decrease as the amount of fluorine substitution increases. On the contrary, perfluoro crown ethers form complexes with certain anions in the gas phase. In order to explore the chemistry of theses new compounds, the preparation of new perfluoro crown ethers, such as multilooped perfluoro crown ethers, is very important. We report in this paper the syntheses of the first perfluoro-spiro-bis[19]crown ethers, perfluoro-spiro-bis-crown-6 (1), perfluoro-spiro-bis[16]crown-5 (2), and perfluoro-spiro-bis[13]crown-4 (3), by elemental fluorine. 12 refs., 3 figs., 1 tab.

Wei, Han-Chao; Lynch, V.M.; Lagow, R.J. [Univ. of Texas, Austin, TX (United States)] [Univ. of Texas, Austin, TX (United States)

1997-03-07

340

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

341

Ether, the Theory of Relativity and Quantum Physics  

NASA Astrophysics Data System (ADS)

In this paper we revisit some of the reasons given by Einstein that resulted in his change of mind about the ether from denying to defending its existence. The ether proposed by Einstein we call Einstein's new ether. We consider the potential use of Einstein's new ether in quantum mechanics. The standard model of elementary particles reveals the existence of at least one component of Einstein's new ether. In this work we explore additional properties of Einstein's new ether. In particular, we consider a recent experiment known as the Afshar experiment due to its implications for the wave particle duality paradox. The Afshar experiment is perhaps the first experiment that provides clear evidence that wave and particle aspects of the photon have some sort of physical reality beyond the limits imposed by complementarity. We propose that the physical reality of the wave aspect of the photon has its origin in Einstein's new ether. Here, we report on consequences of the Afshar experiment for Einstein's new ether.

Flores, Eduardo V.

342

Imide/arylene ether copolymers with pendent trifluoromethyl groups  

NASA Technical Reports Server (NTRS)

A series of imide/arylene ether block copolymers were prepared using an arylene ether block containing a hexafluoroisopropylidene group and an imide block containing a hexafluoroisopropylidene and a trifluoromethyl group in the polymer backbone. The copolymers were characterized and mechanical properties were determined and compared to the homopolymers.

Jensen, Brian J.; Havens, Stephen J.

1992-01-01

343

Antileishmanial ring-substituted ether phospholipids.  

PubMed

Three series of ring-substituted ether phospholipids were synthesized carrying N,N,N-trimethylammonium, N-methylpiperidino, or N-methylmorpholino headgroups. The first series is substituted by 2-cyclohexyloxyethyl or 2-(4-alkylidenecyclohexyloxy)ethyl groups, the second series by cyclohexylidenealkyl or adamantylidenealkyl moieties, and the third series by 2-aryloxyethyl or 6-aryloxyhexyl groups in the alkyl portion of the molecule. The antileishmanial activity of the new compounds was evaluated in vitro against the promastigote forms of L. donovani and L. infantum using an MTT (3-(4,5-dimethylthiazol-2yl)-2,5-diphenyltetrazolium bromide)-based microassay as a marker of cell viability. Analogues 12, 15, 24, 30, 32, 41, 43, and 45 were more potent than the control compound miltefosine (hexadecylphosphocholine) against both L. donovani and L. infantum while, derivatives 13 and 42 were equipotent to miltefosine. Analogues 16, 17, 19, 20 were more potent than miltefosine against L. infantumand compounds 27, 31, 44 were more active than miltefosine against L. donovani. Differential scanning calorimetry (DSC) was used to probe the role of individual ether phospholipids on the physicochemical properties of model membranes. The DSC scans showed that the active compounds have a more profound effect on the thermotropic properties of model membrane bilayers than the less active ones. PMID:12593656

Avlonitis, Nikos; Lekka, Eleni; Detsi, Anastasia; Koufaki, Maria; Calogeropoulou, Theodora; Scoulica, Efi; Siapi, Eleni; Kyrikou, Ioanna; Mavromoustakos, Thomas; Tsotinis, Andrew; Grdadolnik, Simona Golic; Makriyannis, Alexandros

2003-02-27

344

[Polybrominated diphenyl ethers (PBDE)--new threats?].  

PubMed

Polybrominated diphenyl ethers (PBDE) because of their physical and chemical properties belong to Persistent Organic Pollutants (POPs). They are stable in the environment and due to lipophilic properties, have potential impact to human health. Currently these compounds are present in all kind of environmental samples all over the world. Levels of PBDE in samples originated from U.S. are higher than levels reported from Europe and Japan, what may be linked to common use these flame retardants in this country. Environmental (including humans) concentration of PBDE have increased rapidly in the last decade. Predominant congeners detected in all matrices are BDE-47, -99, -153, -209. Recent Swedish report however noticed decrease of PBDE concentrations what can be consequence of phase-out of these compounds in this country. It has been suggested that the environmental levels of PBDE may influence human nervous and immunological system as well as they may disrupt hormonal homeostasis. Research studies suggest also that the exposure to polybrominated diphenyl ethers may be associated with increased risk of cancers. Therefore, continuation of research concerning occurrence and toxicity of PBDE has reasonable grounds. PMID:17929587

Hernik, Agnieszka; Góralczyk, Katarzyna; Czaja, Katarzyna; Struci?ski, Pawe?; Korcz, Wojciech; Ludwicki, Jan K

2007-01-01

345

40 CFR 180.1083 - Dimethyl sulfoxide; exemption from the requirement of a tolerance.  

Code of Federal Regulations, 2010 CFR

...From Tolerances § 180.1083 Dimethyl sulfoxide; exemption from the requirement of a tolerance. Dimethyl sulfoxide (DMSO) [CAS Registry Number 67-68-5] is exempted from the requirement of a tolerance when used as an inert solvent or...

2009-07-01

346

40 CFR 180.1083 - Dimethyl sulfoxide; exemption from the requirement of a tolerance.  

Code of Federal Regulations, 2010 CFR

...From Tolerances § 180.1083 Dimethyl sulfoxide; exemption from the requirement of a tolerance. Dimethyl sulfoxide (DMSO) [CAS Registry Number 67-68-5] is exempted from the requirement of a tolerance when used as an inert solvent or...

2010-07-01

347

Reactions accompanying the chlorination of dimethyl hydrogen phosphite with chlorine  

SciTech Connect

In the chlorination of dimethyl hydrogen phosphite the purity of the dimethyl phosphorochloridate obtained is influenced by the presence of hydrogen chloride in the reaction mixture and the ingress of water into the reaction sphere. With the aid of /sup 31/P NMR spectroscopy it was shown that, when moisture finds its way into the sphere of reaction, in the further distillation of the crude reaction mixture, apart from the latter, trimethyl phosphate formed as a result of the breakdown of tetramethyl pyrophosphate also distills off.

Kir'yazov, M.P.; Belova, L.A.; Soifer, R.S.; Bogel'fer, L.Ya.; Negrebetskii, V.V.; Bakanova, Z.M.

1987-11-20

348

Synthesis and characterization of poly(silyl ether)s and modified poly(siloxane)s  

NASA Astrophysics Data System (ADS)

Activated dihydridocarbonyltris(triphenylphosphine)ruthenium ( Ru) catalyzes the dehydrogenative silylation condensation copolymerization of ortho-quinones with alpha,o-dihydrido-oligodimethylsiloxanes to give high molecular weight copoly(arylene-1,2-dioxy/oligodimethylsiloxanylene)s in good chemical yield. The hydrosilylation polymerization of aliphatic o-dimethylsilyloxy ketones is also catalyzed by activated Ru to yield unsymmetrical poly(silyl ether)s. Likewise, Ru catalyzes the copolymerization of alpha,o-diketones with alpha,o-dihydrido-oligodimethylsiloxanes to yield symmetrical poly(silyl ether)s. A mechanism of the copolymerizations is proposed, in which beta-hydride elimination is favored over reductive elimination in the reaction of the ortho-quinones. Chiral centers affect the NMR spectra of the poly(silyl ether)s produced by hydrosilylation. The photoluminescence properties of the polymers were studied along with those of model compounds. The decrease in Tgs with increase in siloxane chain length as well as fluorescence spectra is discussed. RuH2(CO)(PPh3)3 (Ru), activated with a stoichiometric amount of styrene, catalyzes the anti-Markovnikov addition of an ortho C-H bond of benzophenone across the C-C double bonds of alpha,o-bis(trimethylsilyloxy)copoly(dimethylsiloxane/vinylmethylsiloxane), alpha,o-bis(vinyldimethsilyloxy)poly(dimethylsiloxane)s, and 1,3-divinyltetramethyldisiloxane to yield alpha,o-bis(trimethylsilyloxy)copoly[dimethylsiloxane/2-(2 '-benzophenonyl)ethylmethylsiloxane]s, alpha,o-bis[2-(2 '-benzophenonyl)ethyldimethylsilyloxy]poly(dimethylsiloxane)s, and 1,3-bis[2-(2'-benzophenonyl)ethyl]tetramethyldisiloxane, respectively. While the Mw/Mn and Tgs of the modified polysiloxanes are similar to those of the precursor polymers, an increase in molecular weight is observed upon heating. 1,3-bis[2-(2 '-Benzophenonyl)ethyl]tetramethyldisiloxane, a model compound, was utilized to test a mechanism for the increase in molecular weight. A mechanism is proposed. Fluorinated and non-fluorinated 1,9-bis(epoxyalkyl)pentasiloxanes have been prepared by the Pt-catalyzed hydrosilylation reaction of vinylepoxides with 1,9-dihydridopentasiloxanes. The 1,9-dihydridopentasiloxanes were prepared by the triflic acid-catalyzed ring-opening of the corresponding cyclotrisiloxanes in the presence of 1,1,3,3-tetramethyldisiloxane. Insoluble cross-linked thin films have been prepared by the diaryliodonium salt photo-acid catalyzed ring-opening polymerization of the 1,9-bis(epoxyalkyl)pentasiloxanes. These materials may be useful as anti-corrosion/foul-release coatings for marine applications.

Mabry, Joseph Mark

349

Criteria for a Recommended Standard: Occupational Exposure to Ethylene Glycol Monobutyl Ether and Ethylene Glycol Monobutyl Ether Acetate.  

National Technical Information Service (NTIS)

Standard designed to protect the health and safety of employees exposed to ethylene-glycol-monobutyl-ether (111762) (EGBE) and ethylene-glycol-monobutyl-ether-acetate (112072) (EBGEA) by reducing those exposures to not more than 5 parts per million. The d...

1990-01-01

350

Chronic Skin Absorption of Propylene Glycol Methyl Ether (33b) and Dipropylene Glycol Methyl Ether (50b) in Rabbits.  

National Technical Information Service (NTIS)

Propylene glycol methyl ether (PGME) and dipropylene glycol methyl ether (DGME) were applied via occluded cotton pads to clipped, abraded abdominal skin of male rabbits (5/group; strain not reported) 5 times/week for 3 months. Control animals received dis...

2000-01-01

351

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

PubMed

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

352

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.

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

2014-01-01

353

Effects of monomer and ether structure on metal-free living cationic polymerization of various vinyl ethers using hydrogen chloride with ether  

Microsoft Academic Search

A highly effective initiating system has been achieved for living cationic polymerization of vinyl ethers consisting of HCl\\u000a alone without Lewis acid. This system is a facile metal-free living cationic polymerization using no HCl\\/Lewis acid but the\\u000a already adopted complex HCl·Et2O. In this study, we investigated the effects of a monomer and ether structure on the polymerization behavior. The monomers

Shinji Sugihara; Masaru Kitagawa; Yuichi Inagawa; Izabela Magdalena Zaleska; Isao Ikeda

2010-01-01

354

40 CFR Table 3 to Subpart Ggg of... - Soluble HAP  

Code of Federal Regulations, 2013 CFR

...Acetophenone. Diethyl sulfate. Dimethyl sulfate. Dinitrotoluene. Ethylene glycol dimethyl ether. Ethylene glycol monobutyl ether acetate. Ethylene glycol monomethyl ether acetate. Isophorone. Methanol (methyl...

2013-07-01

355

Characterization and identification of genes essential for dimethyl sulfide utilization in Pseudomonas putida strain DS1  

Microsoft Academic Search

Microbial dimethyl sulfide (DMS) conversion is thought to be involved in the global sulfur cycle. We isolated Pseudomonas putida strain DS1 from soil as a bacterium utilizing DMS as a sole sulfur source, and tried to elucidate the DMS conversion mechanism of strain DS1 at biochemical and genetic level. Strain DS1 oxidized DMS to dimethyl sulfone (DMSO 2) via dimethyl

T. Endoh; K. Kasuga; M. Horinouchi; T. Yoshida; H. Habe; H. Nojiri; T. Omori

2003-01-01

356

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

PubMed Central

In the title compound, [CdI2(C12H12N2)(C2H6OS)], the CdII cation is coordinated by two N atoms from a dimethyl­bipyridine ligand, one O atom from a dimethyl sulfoxide mol­ecule and two I? anions in a distorted trigonal–bipyramidal geometry. Intra­molecular C—H?O hydrogen bonding and inter­molecular ?–? stacking between parallel pyridine rings [centroid–centroid distance = 3.658?(3)?Å] are present in the crystal structure.

Kalateh, Khadijeh; Ahmadi, Roya; Amani, Vahid

2010-01-01

357

(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.

Yousefi, Mohammad

2010-01-01

358

Dibromido(4,4?-dimethyl-2,2?-bipyridine-?2 N,N?)(dimethyl sulfoxide-?O)cadmium  

PubMed Central

In the title compound, [CdBr2(C12H12N2)(C2H6OS)], the CdII atom is five-coordinated in a distorted trigonal–bipyramidal geometry by two N atoms from one 4,4?-dimethyl-2,2?-bipyridine (DMBP) ligand, one O atom from a dimethyl sulfoxide (DMSO) ligand and two Br atoms. A weak intra­molecular C—H?O hydrogen bond occurs between the DMBP and DMSO ligands. ?–? stacking between pyridine rings [centroid–centroid distances = 3.682?(3) and 3.598?(3)?Å] is observed in the crystal.

Shirvan, Sadif A.; Haydari Dezfuli, Sara

2012-01-01

359

(4,4?-Dimethyl-2,2?-bipyridine-?2 N,N?)(dimethyl-formamide-?O)diiodido-cadmium  

PubMed Central

In the title compound, [CdI2(C12H12N2)(C3H7NO)], the CdII cation is five-coordinated in a distorted trigonal–bipyramidal configuration by two N atoms from a 4,4?-dimethyl-2,2?-bipyridine ligand, one O atom from a dimethyl­formamide ligand and two I? anions. ?–? stacking between pyridine rings of adjacent mol­ecules [centroid–centroid distance = 3.666?(3) and 3.709?(4)?Å] stabilizes the three-dimensional structure

Shirvan, Sadif A.; Haydari Dezfuli, Sara; Khazali, Fereydoon; Borsalani, Ali

2012-01-01

360

Trichlorido(4,4?-dimethyl-2,2?-bipyridine-?2 N,N?)(dimethyl sulfoxide-?O)indium(III)  

PubMed Central

In the mol­ecule of the title compound, [InCl3(C12H12N2)(C2H6OS)], the InIII atom is six-coordinated in a distorted octa­hedral configuration by two N atoms from the chelating 4,4?-dimethyl-2,2?-bipyridine ligand, one O atom from dimethyl sulfoxide and three Cl atoms. In the crystal structure, inter­molecular C—H?Cl hydrogen bonds link the mol­ecules into centrosymmetric dimers.

Ahmadi, Roya; Kalateh, Khadijeh; Abedi, Anita; Amani, Vahid; Khavasi, Hamid Reza

2008-01-01

361

Dibromido(2,9-dimethyl-1,10-phenanthroline-?2 N,N?)(dimethyl sulfoxide-?O)cadmium  

PubMed Central

In the mol­ecule of the title compound, [CdBr2(C14H12N2)(C2H6OS)], the CdII atom is five-coordinated in a distorted trigonal–bipyramidal configuration by two N atoms from a 2,9-dimethyl-1,10-phenanthroline ligand, one O atom from a dimethyl sulfoxide ligand and two Br atoms. In the crystal, ?–? contacts between the pyridine and benzene rings [centroid–centroid distances = 3.710?(5), 3.711?(6) and 3.627?(5)?Å] stabilize the structure.

Moghanlou, Khadijeh

2013-01-01

362

Wear of ceramic-on-carbon fiber-reinforced poly-ether ether ketone hip replacements.  

PubMed

Total hip replacement has been a successful surgical intervention for over 50 years, with the majority of bearings using a polyethylene cup. Long-term failure due to osteolysis and loosening has been widely documented and alternative bearings have been sought. A novel carbon fiber-reinforced poly-ether ether ketone (CFR-PEEK) cup was investigated through experimental friction and wear studies. Friction studies demonstrated the bearings operated in a boundary lubrication condition, with friction factors higher than those for other hip replacement bearings. The wear study was conducted with 36 mm diameter bearings tested against Biolox Delta heads for a period of 10 million cycles. The mean volumetric wear rate was 0.3 mm(3)/Mc, indicating the ceramic-on-CFR-PEEK bearing to be a very low wearing option for total hip replacement. PMID:22454322

Brockett, Claire L; John, Gemma; Williams, Sophie; Jin, Zhongmin; Isaac, Graham H; Fisher, John

2012-08-01

363

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

NASA Astrophysics Data System (ADS)

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 thickness of 50 ?m. As the electrodes of the capacitor are made from same p dopable Pani material, the cell is a type I (p-p) capacitor. The cell characteristics are studied using cyclic voltammetry, charging-discharging, and impedance analysis. The unit cell capacitance is 0.6 F, which corresponds to 27 F per g of the active polymer material.

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

364

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

NASA Astrophysics Data System (ADS)

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; Boyer, François; Puech, Pascal; Olivier, Philippe; Sapelkin, Andrei; King, Stephen; Heenan, Richard; Pons, François; Gauthier, Bénédicte; Cadaux, Pierre-Henri; Bacsa, Wolfgang

2014-06-01

365

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.

366

Thermolysis of phenethyl phenyl ether: A model of ether linkages in low rank coal  

SciTech Connect

Currently, an area of interest and frustration for coal chemists has been the direct liquefaction of low rank coal. Although low rank coals are more reactive than bituminous coals, they are more difficult to liquefy and offer lower liquefaction yields under conditions optimized for bituminous coals. Solomon, Serio, and co-workers have shown that: in the pyrolysis and liquefaction of low rank coals, a low temperature cross-linking reaction associated with oxygen functional groups occurs before tar evolution. A variety of pretreatments (demineralization, alkylation, and ion-exchange) have been shown to reduce these retrogressive reactions and increase tar yields, but the actual chemical reactions responsible for these processes have not been defined. In order to gain insight into the thermochemical reactions leading to cross-linking in low rank coal, we have undertaken a study of the pyrolysis of oxygen containing coal model compounds. Solid state NMR studies suggest that the alkyl aryl ether linkage may be present in modest amounts in low rank coal. Therefore, in this paper, we will investigate the thermolysis of phenethyl phenyl ether (PPE) as a model of 0-aryl ether linkages found in low rank coal, lignites, and lignin, an evolutionary precursor of coal. Our results have uncovered a new reaction channel that can account for 25% of the products formed. The impact of reaction conditions, including restricted mass transport, on this new reaction pathway and the role of oxygen functional groups in cross-linking reactions will be investigated.

Britt, P.F.; Buchanan, A.C. III; Malcolm, E.A.

1994-09-01

367

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

368

Sorption of Alkyl Benzyl Dimethyl Ammonium Compounds by Activated Sludge  

Microsoft Academic Search

The adsorption isotherms on activated sludge from wastewater treatment plants and the surface properties in aqueous solution of alkyl benzyl dimethyl ammonium compounds have been investigated. Langmuir and Freundlich adsorption isotherms described satisfactorily the equilibrium adsorption of these cationic surfactants on activated sludge. Adsorption on sludge as well as the affinity of these compounds to be adsorbed in the liquid\\/gas

M. Teresa García; Encarna Campos; Francesc Comelles

2006-01-01

369

Dimethyl Sulfoxide in Plastic Surgery of the Skin.  

National Technical Information Service (NTIS)

Dimethyl sulfoxide (DMSO) possesses a number of valuable properties. It exhibits a preservative effect in the storage of tissue and successful results in the transplantation of human skin stored for extended periods (up to 608 days) in 10 percent DMSO sol...

M. F. Kamaev

1970-01-01

370

DIMETHYL AND METHYL HYDROGEN SULFATE IN THE ATMOSPHERE  

EPA Science Inventory

A novel technique of using the sample tube penetration profile of trace reactive gases has been applied to the sampling and indirect identification of candidate species through their diffusion coefficients. Laboratory studies of trace dimethyl and methyl hydrogen sulfate flow and...

371

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.

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

2009-01-01

372

Analytical application of functionalized crown ether - metal complexes  

SciTech Connect

The introduction of functional groups such as lipophilic substituents, non-ionic ligating sites, acid-dissociable groups, chromophores, chiral centers, into skeleton of crown ether, and their immobilization through incorporation into polymer matrix in order to modify crown ethers to versatile analytical reagents in chromatography, ion-selective electrode, colorimetry, etc., is presented. After a brief summary of recent syntheses of functionalized crown ethers, their applications in analytical chemistry are discussed with emphasis on the behavior of metal-complex formation. 103 references, 9 tables.

Takagi, M.; Nakamura, H.

1986-01-01

373

Dehydration of scandium chloride hydrate: synthesis and molecular structures of ScCl 3(? 2DME)(MeCN), ScCl 3(diglyme) and [Sc 2(?-OH) 2(H 2O) 10]Cl 4·2H 2O  

Microsoft Academic Search

Various dehydration procedures have been evaluated for ScCl3·6H2O. The ScCl3(DME)(MeCN) 1 and ScCl3(diglyme) 2 [diglyme=MeO(CH2CH2O)2Me] adducts have been synthesized by a ligand-exchange reaction from ScCl3(THF)3 in acetonitrile. The diglyme adduct could also be obtained by dehydration of ScCl3·6H2O by trimethylchlorosilane in diethylether in the presence of the ligand. The complexes were characterized by FT–IR, 1H NMR and by X-ray diffraction.

Valérie Ripert; Liliane G. Hubert-Pfalzgraf; Jacqueline Vaissermann

1999-01-01

374

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.

Information Center

2006-02-01

375

Decomposition of vinyl ethers by alkalide K ?, K +(15-crown-5) 2 via organopotassium intermediates  

Microsoft Academic Search

The structure of vinyl ethers determines the direction of the C–O bond cleavage by alkalide K?, K+(15-crown-5)21. Highly reactive organopotassium compounds are intermediate products formed in the system containing phenyl vinyl ether, butyl vinyl ether, ethylene glycol butyl vinyl ether or triethylene glycol methyl vinyl ether. Vinylpotassium and butylpotassium react with 15-crown-5. The oxacyclic ring of the latter is opened

Zbigniew Grobelny; Andrzej Stolarzewicz; Adalbert Maercker; Stanis?aw Krompiec; Janusz Kasperczyk; Józef Rzepa

2004-01-01

376

Tert-Amyl Methyl Ether Catalytic Distillation Experiments and Simulations.  

National Technical Information Service (NTIS)

In this work the catalytic section of a reactive distillation column is studied. Experimental studies with a laboratory catalytic distillation column were carried out for the decomposition and production of tert-amyl methyl ether (TAME). The purpose of th...

K. Klemola A. Pyhaelahti

1996-01-01

377

Protonation in Acetonitrile of Water, Alcohols, and Diethyl Ether.  

National Technical Information Service (NTIS)

The protonation in acetonitrile (AN) of the bases (B) water, alcohols and diethyl ether has been studied by determining spectrophotometrically with Hammett indicators and dibromothymolbenzein their interaction with the solvated proton. Water forms the spe...

I. M. Kolthoff M. K. Chantooni

1967-01-01

378

Diphenyl Ether Derivatives and Their Use for Imaging Serotonin Transporters.  

National Technical Information Service (NTIS)

This invention relates to diphenyl ether derivatives and their use in imaging of Serotonin Transporters (SERTS). The present invention also provides diagnostic compositions comprising the compounds of the present invention, and a pharmaceutically acceptab...

H. F. Kung

2005-01-01

379

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...

380

Marine Sponge Dysidea herbacea revisited: Another Brominated Diphenyl Ether  

PubMed Central

A pentabrominated phenolic diphenyl ether (1) that has not previously been reported from marine sources has been isolated from Dysidea herbacea collected at Pelorus Island, Great Barrier Reef, Australia. The structure was determined by comparison of NMR data with those of known structurally-related metabolites. NMR spectral assignments for (1) are discussed in context with those of three previously reported isomeric pentabrominated phenolic diphenyl ethers.

Agrawal, Madhavi S.; Bowden, Bruce F.

2005-01-01

381

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

382

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

383

Near fatal respiratory distress following massive ether intravenous injection  

Microsoft Academic Search

To the best of our knowledge, no case of ether-induced acute respiratory distress syndrome (ARDS) has been published as yet.\\u000a A 36-year-old female developed pneumonitis which showed all the characteristics of a chemical-associated ARDS due to intravenous\\u000a self-administration of ether: the hemodynamic investigation demonstrated a normal blood flow pattern with low left-heart filling\\u000a pressure while the anteroposterior roentgenogram evidenced disseminated

B. Lambermont; C. Dubois; V. Fraipont; V. D’Orio; L. Radoux

1998-01-01

384

Crown Ethers in Nonaqueous Electrolytes for Lithium\\/Air Batteries  

Microsoft Academic Search

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

Wu Xu; Jie Xiao; Deyu Wang; Jian Zhang; Ji-Guang Zhang

2010-01-01

385

Vinyl ethers Communication 7. Ion and radical-induced homo- and co-polymerization of vinyl ethers of cyclohexanol,decahydro-2-naphthol, and 2-naphthol  

Microsoft Academic Search

1.A study was made of the homo- and co-polymerization of cyclohexyl, decahydro-2-naphthyl, and 2-naphthyl vinyl ethers by ionic and free-radical mechanisms.2.Conditions were found for the preparation in good yield of polymers of cyclohexyl, decahydro-2-naphthyl, and 2- naphthyl vinyl ethers and of their copolymers with ethyl, butyl, and phenyl vinyl ethers in presence of the BF3-ether complex. Most of these polymers

A. V. Bogdanova; M. F. Shostakovskii; G. K. Krasil'nikova

1958-01-01

386

Kinetic Studies of the Free Cationic Polymerization of Ethyl Vinyl Ether and Isobutyl Vinyl Ether Initiated by Triphenylmethyl Hexachloroantimonate.  

National Technical Information Service (NTIS)

The absolute rate constants for the cationic polymerization of ethyl and isobutyl vinyl ethers have been determined in methylene chloride solution. Under the conditions used, the polymerization proceeded by 'free ions'. Extremely rigorous drying procedure...

Y. J. Chung J. M. Rooney D. R. Squire V. Stannett

1974-01-01

387

PROTECTION OF TISSUE-CULTURE CELLS AGAINST IONIZING RADIATION. II. THE ACTIVITY OF HYPOXIA, DIMETHYL SULPHOXIDE, DIMETHYL SULPHONE, GLYCEROL AND CYSTEAMINE AT ROOM TEMPERATURE AND AT -196 C  

Microsoft Academic Search

Protection against x irradiation by hypoxia, glycerol, dimethyl ; sulfoxide, dimethyl sulfone, cystearnine, and a combination of glycerol and ; cysteamine was investigated at +20 deg C and -198 deg C. The protective power of ; the treatment was assayed as the degree to which it prevented radiation damage, ; i.e., the loss of the reproductive integrity of tissue-culture cells.

O. Vos; M. C. A. C. Kaalen

1962-01-01

388

Polybrominated diphenyl ethers in California wastestreams.  

PubMed

Polybrominated diphenyl ethers (PBDEs) are used in consumer products, including electronics, fabrics, and polyurethane foam. Exposures may occur during the products' useful lifetime and also after the products' disposal. A survey of California wastestreams (e-wastes, autoshredder waste and wastewater sewage sludge) attempted to assess the relative importance of these wastestreams as repositories of PBDEs. Based on measurements of PBDEs in samples of such wastestreams and on assumptions regarding use patterns, e-wastes appeared to be by far the predominant wastestream with 1200 metric tons (MT) of PBDEs year(-1), followed by autoshredder waste (31 MT of PBDEs year(-1)) and sewage sludge (2.3 MT of PBDEs year(-1)). When these estimates were compared with the reported use of PBDEs in California, about half of the PBDEs could not be accounted for in the wastestreams examined. This suggests that additional wastestreams, such as household wastes should be evaluated for their PBDE content. Information on the presence and fate of PBDEs in all wastestreams needs to be included in decision making practices for waste management to avoid public health and ecologic catastrophes. PMID:19027926

Petreas, Myrto; Oros, Daniel

2009-02-01

389

Synthesis of poly(silyl ether) by the addition reaction of bisphenol-S diglycidyl ether and dichlorodiphenylsilane  

Microsoft Academic Search

In this study, a new poly(silyl ether) with reactive pendant chloromethyl groups was synthesized by an addition reaction between dichlorodiphenylsilane (CPS) and the diglycidyl ether of bisphenol-S (bisphenol-S epoxy). The polyaddition proceeded very smoothly and regioselectively in toluene catalysed by quaternary ammonium or phosphonium salts such as tetrabutylammonium bromide, tetrabutylammonium fluoride and tetrabutylphosphonium bromide to produce a polymer with high

Der-Jang Liaw

1997-01-01

390

Study of ion\\/molecule reactions of ion derived from tert-butyl methyl ether and trimethylsilyl methyl ether  

Microsoft Academic Search

The ion\\/molecule reactions of the ions (CH3)2C+–OCH3 (1a) and (CH3)2Si+–OCH3 (2a), which are the main fragment ions in the electron ionization mass spectrum of tert-butyl methyl ether (MTBE, 1) and trimethylsilyl methyl ether (MTSE, 2), respectively, and of the protonated MTBE (1H+) and protonated MTSE (2H+), generated by chemical ionization, with MTBE or MTSE, with acetone and with ammonia have

Michael Büchner; Hans Friedrich Grützmacher

2000-01-01

391

High flux asymmetric gas separation membranes of modified poly(ether ether ketone) prepared by the dry phase inversion technique  

Microsoft Academic Search

Asymmetric membranes with a dense skin were prepared by the dry phase inversion technique, from a casting solution of a modified poly(ether ether ketone), PEEKWC, in dichloromethane, chloroform and tetrahydrofuran as solvents and C1–C4, C8 aliphatic alcohols and\\/or water as nonsolvents. The phase diagram of the different polymer\\/solvent\\/nonsolvent combinations was determined by cloud point measurements.The influence of the polymer concentration,

J. C. Jansen; M. Macchione; E. Drioli

2005-01-01

392

The effect of sulfonated poly(ether ether ketone) as an electrode binder for direct methanol fuel cell (DMFC)  

Microsoft Academic Search

Poly(ether ether ketones) (PEEKs) are sulfonated and used as a binder in the electrode for DMFC studies. The effect of sulfonated PEEK (s-PEEK) binder in the catalyst layer on the cell performance is investigated. The s-PEEK binder in the electrode is found to be more efficient in maintaining long-term stability of the cell performance than the conventional Nafion binder. The

Ho-Young Jung; Ki-Yun Cho; Kyung A Sung; Wan-Keun Kim; Jung-Ki Park

2006-01-01

393

Direct synthesis of sulfonated aromatic poly(ether ether ketone) proton exchange membranes for fuel cell applications  

Microsoft Academic Search

Proton exchange membrane fuel cells (PEMFC) are promising new power sources for vehicles and portable devices. Membranes currently used in PEMFC are perfluorinated polymers such as Nafion®. Even though such membranes have demonstrated good performances and long-term stability, their high cost and methanol crossover makes them unpractical for large-scale production. Sulfonated aromatic poly(ether ether ketones) (S-PEEKs) based membranes have been

Maria Gil; Xiangling Ji; Xianfeng Li; Hui Na; J. Eric Hampsey; Yunfeng Lu

2004-01-01

394

Synthesis and reactions of vinyl ethers of ethanolamines communication 8. Vinyl ethers of 2-dimethylaminoethanol and 2-(2,5-dichloroanilino) ethanol  

Microsoft Academic Search

Summary 1.The vinyl ethers of 2- dirnethylamino ethanol and of 2-(2,5-dichloroanilino) ethanol were prepared, and some reactions of these ethers were investigated.2.The reaction of 2-(2,5-dichloroanilino) ethanol with butyl vinyl ether was studied.

M. F. Shostakovsky; I. A. Chekulaeva

1957-01-01

395

Yb(OTf) 3\\/FeCl 3 mediated facile conversion of alcohols, ketals and acid sensitive ethers into diphenylmethyl (DPM) ethers  

Microsoft Academic Search

10 mol% Yb(OTf)3 or FeCl3 have been developed as efficient reagents for the conversion of alcohols into diphenylmethyl (DPM) ethers. Similarly, FeCl3 has also been advantageously utilised to successfully convert ketals and acid sensitive ethers into DPM ethers.

G. V. M. Sharma; T. Rajendra Prasad; A. K. Mahalingam

2001-01-01

396

Alkyl dimethyl benzyl ammonium chloride adsorption mechanism on wood  

Microsoft Academic Search

The adsorption of alkyl dimethyl benzyl ammonium chloride (ADBAC) on wood was investigated. The changes in zeta potential\\u000a curves of wood and ADBAC adsorption with increasing ADBAC concentration were highly correlated and showed two different mechanisms\\u000a for ADBAC adsorption on wood: ion exchange reaction at low concentration and additional aggregation form of adsorption by\\u000a hydrophobic interaction at high concentration. ADBAC

Myung Jae Lee; Paul Cooper

2010-01-01

397

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

398

Trace derivatization of cytosine with pentafluorobenzoyl chloride and dimethyl sulfate.  

PubMed Central

Methods are being developed for derivatizing trace amounts of DNA adducts for ultimate determination by gas chromatographic techniques. High-pressure liquid chromatography is used to optimize appropriate derivatization reactions for the determination of cytosine. A single vial reaction scheme involves acylation with electrophoric pentafluorobenzoylchloride followed by alkylation with dimethyl sulfate. Currently, the overall yield for this reaction starting with 50 nmole of cytosine is 59 +/- 4.6%.

Fisher, D H; Adams, J; Giese, R W

1985-01-01

399

2-[(Dimethyl-amino)-methyl-idene]propane-dinitrile  

PubMed Central

In the title moleclue, C6H7N3, the mean plane of the dimethyl­amino group [maximum deviation = 0.006?(2)?Å] forms a dihedral angle of 7.95?(18)° with the mean plane of the propane­dinitrile fragment [maximum deviation = 0.008?(2)?Å]. In the crystal, weak C—H?N hydrogen bonds link the mol­ecules into a three-dimensional network.

Kant, Rajni; Gupta, Vivek K.; Kapoor, Kamini; Patil, D. R.; Deshmukh, Madhukar B.

2013-01-01

400

Bis(phenanthridinium) hexa-chloridoplatinate(IV) dimethyl sulfoxide disolvate  

PubMed Central

The asymmetric unit of the title compound, (C13H10N)2[PtCl6]·2C2H6OS, contains one independent protonated phenanthridinium cation, half of a centrosymmetric [PtCl6]2?anion and one dimethyl sulfoxide solvent mol­ecule. Intra­molecular N—H?O and inter­molecular C—H?Cl hydrogen-bonding inter­actions seem to be effective in the stabilization of the structure.

Karaca, Selvi; Akkurt, Mehmet; Safari, Nasser; Amani, Vahid; Buyukgungor, Orhan; Abedi, Anita

2009-01-01

401

A self-healing poly(dimethyl siloxane) elastomer  

Microsoft Academic Search

In this work, self-healing functionality is imparted to a poly(dimethyl siloxane) (PDMS) elastomer with low modulus and high strain-to-failure behavior. This material utilizes a two-microcapsule system to provide a mechanism for autonomic repair of damage. One microcapsule type contains a functionalized high-molecular-weight resin and organometallic catalyst compounds. The second microcapsule type contains a functional copolymer (initiator) that facilitates the crosslinking

Michael Wade Keller

2007-01-01

402

Organellar Proteomics Reveals Golgi Arginine DimethylationD?  

PubMed Central

The Golgi complex functions to posttranslationally modify newly synthesized proteins and lipids and to sort them to their sites of function. In this study, a stacked Golgi fraction was isolated by classical cell fractionation, and the protein complement (the Golgi proteome) was characterized using multidimensional protein identification technology. Many of the proteins identified are known residents of the Golgi, and 64% of these are predicted transmembrane proteins. Proteins localized to other organelles also were identified, strengthening reports of functional interfacing between the Golgi and the endoplasmic reticulum and cytoskeleton. Importantly, 41 proteins of unknown function were identified. Two were selected for further analysis, and Golgi localization was confirmed. One of these, a putative methyltransferase, was shown to be arginine dimethylated, and upon further proteomic analysis, arginine dimethylation was identified on 18 total proteins in the Golgi proteome. This survey illustrates the utility of proteomics in the discovery of novel organellar functions and resulted in 1) a protein profile of an enriched Golgi fraction; 2) identification of 41 previously uncharacterized proteins, two with confirmed Golgi localization; 3) the identification of arginine dimethylated residues in Golgi proteins; and 4) a confirmation of methyltransferase activity within the Golgi fraction.

Wu, Christine C.; MacCoss, Michael J.; Mardones, Gonzalo; Finnigan, Claire; Mogelsvang, Soren; Yates, John R.; Howell, Kathryn E.

2004-01-01

403

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

404

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

405

The Effects of Sulfonated Poly(ether ether ketone) Ion Exchange Preparation Conditions on Membrane Properties  

PubMed Central

A low cost cation exchange membrane to be used in a specific bioelectrochemical system has been developed using poly(ether ether ketone) (PEEK). This material is presented as an alternative to current commercial ion exchange membranes that have been primarily designed for fuel cell applications. To increase the hydrophilicity and ion transport of the PEEK material, charged groups are introduced through sulfonation. The effect of sulfonation and casting conditions on membrane performance has been systematically determined by producing a series of membranes synthesized over an array of reaction and casting conditions. Optimal reaction and casting conditions for producing SPEEK ion exchange membranes with appropriate performance characteristics have been established by this uniquely systematic experimental series. Membrane materials were characterized by ion exchange capacity, water uptake, swelling, potential difference and NMR analysis. Testing this extensive membranes series established that the most appropriate sulfonation conditions were 60 °C for 6 h. For mechanical stability and ease of handling, SPEEK membranes cast from solvent casting concentrations of 15%–25% with a resulting thickness of 30–50 µm were also found to be most suitable from the series of tested casting conditions. Drying conditions did not have any apparent impact on the measured parameters in this study. The conductivity of SPEEK membranes was found to be in the range of 10?3 S cm?1, which is suitable for use as a low cost membrane in the intended bioelectrochemical systems.

Yee, Rebecca S. L.; Zhang, Kaisong; Ladewig, Bradley P.

2013-01-01

406

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

407

The Effects of Sulfonated Poly(ether ether ketone) Ion Exchange Preparation Conditions on Membrane Properties.  

PubMed

A low cost cation exchange membrane to be used in a specific bioelectrochemical system has been developed using poly(ether ether ketone) (PEEK). This material is presented as an alternative to current commercial ion exchange membranes that have been primarily designed for fuel cell applications. To increase the hydrophilicity and ion transport of the PEEK material, charged groups are introduced through sulfonation. The effect of sulfonation and casting conditions on membrane performance has been systematically determined by producing a series of membranes synthesized over an array of reaction and casting conditions. Optimal reaction and casting conditions for producing SPEEK ion exchange membranes with appropriate performance characteristics have been established by this uniquely systematic experimental series. Membrane materials were characterized by ion exchange capacity, water uptake, swelling, potential difference and NMR analysis. Testing this extensive membranes series established that the most appropriate sulfonation conditions were 60 °C for 6 h. For mechanical stability and ease of handling, SPEEK membranes cast from solvent casting concentrations of 15%-25% with a resulting thickness of 30-50 µm were also found to be most suitable from the series of tested casting conditions. Drying conditions did not have any apparent impact on the measured parameters in this study. The conductivity of SPEEK membranes was found to be in the range of 10-3 S cm-1, which is suitable for use as a low cost membrane in the intended bioelectrochemical systems. PMID:24956945

Yee, Rebecca S L; Zhang, Kaisong; Ladewig, Bradley P

2013-01-01

408

Enhanced osteoblast responses to poly ether ether ketone surface modified by water plasma immersion ion implantation.  

PubMed

Poly ether ether ketone (PEEK) offers a set of characteristics superior for human implants; however, its application is limited by the bio-inert surface property. In this work, PEEK surface was modified using single step plasma immersion ion implantation (PIII) treatment with a gas mixture of water vapor as a plasma resource and argon as an ionization assistant. Field emission scanning electron microscopy, atomic force microscopy and X-ray photoelectron spectroscopy were used to investigate the microstructure and composition of the modified PEEK surface. The water contact angle and zeta-potential of the surfaces were also measured. Osteoblast precursor cells MC3T3-E1 and rat bone mesenchymal stem cells were cultured on the PEEK samples to evaluate their cytocompatibility. The obtained results show that the hydroxyl groups as well as a "ravined structure" are constructed on water PIII modified PEEK. Compared with pristine PEEK, the water PIII treated PEEK is more favorable for osteoblast adhesion, spreading and proliferation, besides, early osteogenic differentiation indicated by the alkaline phosphatase activity is also up-regulated. Our study illustrates enhanced osteoblast responses to the PEEK surface modified by water PIII, which gives positive information in terms of future biomedical applications. PMID:24632035

Wang, Heying; Lu, Tao; Meng, Fanhao; Zhu, Hongqin; Liu, Xuanyong

2014-05-01

409

Highly stable alkaline polymer electrolyte based on a poly(ether ether ketone) backbone.  

PubMed

Alkaline polymer electrolyte fuel cells (APEFCs) promise the use of nonprecious metal catalysts and thus have attracted much research attention in the recent decade. Among the challenges of developing practical APEFC technology, the chemical stability of alkaline polymer electrolytes (APEs) seems to be rather difficult. Research found that, upon attachment of a cationic functional group, an originally stable polymer backbone, such as polysulfone (PSF), would degrade in an alkaline environment. In the present work, we try to employ poly(ether ether ketone) (PEEK), a very inert engineering plastic, as the backbone of APEs. The PEEK is functionalized with both a sulfonic acid (SA) group and a quaternary ammonia (QA) group, with the latter as the majority amount. Ionic cross-linking between SA and QA has rendered the thus-obtained membrane (xQAPEEK) with high mechanical strength and low swelling degree. More importantly, the xQAPEEK membrane exhibits outstanding stability in a 1 mol/L KOH solution at 80 °C for a test period of 30 days: the total weight loss of xQAPEEK is only 6 wt %, in comparison to a large degradation of quaternary ammonia PSF (more than 40 wt %) under the same conditions. Our findings not only have demonstrated an effective approach to preparing PEEK-based APE but also cast a new light on the development of highly stable APEs for fuel-cell application. PMID:24229363

Han, Juanjuan; Peng, Hanqing; Pan, Jing; Wei, Ling; Li, Guangwei; Chen, Chen; Xiao, Li; Lu, Juntao; Zhuang, Lin

2013-12-26

410

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

411

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-l-propanol (isobutanol). The overall scheme involves gasification of coal, purification and shifting of the synthesis gas, higher alcohol synthesis, and direct synthesis of ethers. The last stage of the synthesis involves direct coupling of synthesis gas-derived methanol and isobutanol that has been demonstrated by us to occur over superacid catalysts to yield methyl isobutyl ether (MIBE) at moderate pressures and a mixture of methanol and isobutene at low pressures. MIBE is an isomer of MTBE and a process is proposed whereby MTBE from the two alcohols is maximized and MIBE is minimized. This will be achieved by the proper choice of reaction conditions, i.e. intermediate pressures, and of inorganic acid catalysts that are stable at temperatures higher than 200[degree]C, at which the carbonium ion reaction coupling of the two alcohols to MTBE is more effective than the oxonium ion or ester reaction coupling to MIBE. Both organic and inorganic catalysts will be investigated, and the better catalysts of these classes will be subjected to long term performance studies. The long term performance studies of the combined process will extend to 1000 hr and detailed analytical data for all products will be provided.

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

1992-07-01

412

Vinyl ether resist system for UV-cured nanoimprint lithography  

NASA Astrophysics Data System (ADS)

Cationic curing of vinyl ethers for step-and-flash nanoimprint lithography is described. Photochemical acid generators for use in the vinyl ether formulation were carefully selected on the basis of their solubility in neat lipophilic vinyl ether. Our favorite acid generators include diphenyltolylsulfonium triflate, CGI261, CGI1905, CGI1906, and CGI1907. The CGI1900 series is sensitive to i-line irradiation while the former two can be sensitized to 365 nm radiation by adding 9-anthracenemethanol. Phenothiazine is also an effective i-line sensitizer of the sulfonium salt. A major problem associated with the vinyl ether curing material is poor storage stability and the formulation rapidly solidifies at room temperature. However, it has been found that anthracenemethanol can stabilize the sulfonium salt and CGI formulations against the aging. Phenothiazine extends the shelf life of the sulfonium salt system but violently reacts with the CGI PAGs. Volatility of the vinyl ethers was measured by thermogravimetric analysis at room temperature. Photochemical curing of the formulations was investigated by FT-IR and also by differential scanning calorimetry (DSC) equipped with a UV lamp. The photo-DSC analysis was particularly useful in ascertaining the cure kinetics and the efficacy of the sensitization. Preliminary imprint experiments successfully printed 50 nm dense features.

Ito, Hiroshi; Houle, Frances A.; Hart, Mark W.; DiPietro, Rick A.

2006-03-01

413

Anaerobic versus Aerobic Degradation of Dimethyl Sulfide and Methanethiol in Anoxic Freshwater Sediments  

PubMed Central

Degradation of dimethyl sulfide and methanethiol in slurries prepared from sediments of minerotrophic peatland ditches were studied under various conditions. Maximal aerobic dimethyl sulfide-degrading capacities (4.95 nmol per ml of sediment slurry · h?1), measured in bottles shaken under an air atmosphere, were 10-fold higher than the maximal anaerobic degrading capacities determined from bottles shaken under N2 or H2 atmosphere (0.37 and 0.32 nmol per ml of sediment slurry · h?1, respectively). Incubations under experimental conditions which mimic the in situ conditions (i.e., not shaken and with an air headspace), however, revealed that aerobic degradation of dimethyl sulfide and methanethiol in freshwater sediments is low due to oxygen limitation. Inhibition studies with bromoethanesulfonic acid and sodium tungstate demonstrated that the degradation of dimethyl sulfide and methanethiol in these incubations originated mainly from methanogenic activity. Prolonged incubation under a H2 atmosphere resulted in lower dimethyl sulfide degradation rates. Kinetic analysis of the data resulted in apparent Km values (6 to 8 ?M) for aerobic dimethyl sulfide degradation which are comparable to those reported for Thiobacillus spp., Hyphomicrobium spp., and other methylotrophs. Apparent Km values determined for anaerobic degradation of dimethyl sulfide (3 to 8 ?M) were of the same order of magnitude. The low apparent Km values obtained explain the low dimethyl sulfide and methanethiol concentrations in freshwater sediments that we reported previously. Our observations point to methanogenesis as the major mechanism of dimethyl sulfide and methanethiol consumption in freshwater sediments.

Lomans, Bart P.; Op den Camp, Huub J. M.; Pol, Arjan; Vogels, Godfried D.

1999-01-01

414

40 CFR 63.63 - Deletion of ethylene glycol monobutyl ether from the list of hazardous air pollutants.  

Code of Federal Regulations, 2010 CFR

...2009-07-01 false Deletion of ethylene glycol monobutyl ether from the list...List § 63.63 Deletion of ethylene glycol monobutyl ether from the list...pollutants. The substance ethylene glycol monobutyl ether...

2009-07-01

415

40 CFR 63.63 - Deletion of ethylene glycol monobutyl ether from the list of hazardous air pollutants.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 false Deletion of ethylene glycol monobutyl ether from the list...List § 63.63 Deletion of ethylene glycol monobutyl ether from the list...pollutants. The substance ethylene glycol monobutyl ether...

2010-07-01

416

40 CFR 721.10209 - Epoxy terminated, hydrolyzed trialkoxysilane and glycidyl ether of phenol-formaldehyde resin...  

Code of Federal Regulations, 2011 CFR

...glycidyl ether of phenol-formaldehyde resin (generic). 721.10209 Section 721...glycidyl ether of phenol-formaldehyde resin (generic). (a) Chemical substance...glycidyl ether of phenol-formaldehyde resin (PMN P-09-120) is subject to...

2011-07-01

417

40 CFR 721.10209 - Epoxy terminated, hydrolyzed trialkoxysilane and glycidyl ether of phenol-formaldehyde resin...  

Code of Federal Regulations, 2012 CFR

...glycidyl ether of phenol-formaldehyde resin (generic). 721.10209 Section 721...glycidyl ether of phenol-formaldehyde resin (generic). (a) Chemical substance...glycidyl ether of phenol-formaldehyde resin (PMN P-09-120) is subject to...

2012-07-01

418

40 CFR 721.6181 - Fatty acid, reaction product with substituted oxirane, formaldehyde-phenol polymer glycidyl ether...  

Code of Federal Regulations, 2010 CFR

...substituted oxirane, formaldehyde-phenol polymer glycidyl ether, substituted proplyamine...substituted oxirane, formaldehyde-phenol polymer glycidyl ether, substituted proplyamine...substituted oxirane, formaldehyde-phenol polymer glycidyl ether, substituted...

2010-07-01

419

40 CFR 721.6980 - Dimer acids, polymer with polyalkylene glycol, bisphenol A-diglycidyl ether, and alky-lenepolyols...  

Code of Federal Regulations, 2010 CFR

...acids, polymer with polyalkylene glycol, bisphenol A-diglycidyl ether, and alky-lenepolyols...acids, polymer with polyalkylene glycol, bisphenol A-diglycidyl ether, and alky-lenepolyols...polymer with polyalkylene glycol, bisphenol A-diglycidyl ether, and...

2010-07-01

420

40 CFR 721.6980 - Dimer acids, polymer with polyalkylene glycol, bisphenol A-diglycidyl ether, and alky-lenepolyols...  

Code of Federal Regulations, 2010 CFR

...acids, polymer with polyalkylene glycol, bisphenol A-diglycidyl ether, and alky-lenepolyols...acids, polymer with polyalkylene glycol, bisphenol A-diglycidyl ether, and alky-lenepolyols...polymer with polyalkylene glycol, bisphenol A-diglycidyl ether, and...

2009-07-01

421

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

422

Analysis of anions in hydrofluoro ethers by ion chromatography.  

PubMed

Hydrofluoro ethers (HFES) are considered to be an ideal cleaning solvent in applications like vapor degreasing and wet cleaning. It is also a good solvent replacement for CFCs (chlorofluorocarbons), HCFCs (hydrochlorofluorocarbons), HFCs (hydrofluorocarbons) and chlorinated solvents because they have a short atmospheric lifetime and low global warming potential. Based upon their properties, hydrofluoro ethers are ideally suited for the demands of the electronics industry. However, the electronics industry requires these solvents to have high purity, especially in the area of residual anions. This paper will present information on an extraction methodology for the transfer of anions from the hydrofluoro ether to water. Then, an analytical method utilizing ion chromatography that is capable of detection of 10 anions (fluoride, acetate, formate, chloride, nitrite, bromide, nitrate, sulfate, oxalate, and phosphate) in the part per billion level will be demonstrated. PMID:15250412

Hulteen, John C; Schaible, Sandi M

2004-06-11

423

Production of tertiary alkyl ether using improved zeolite catalyst  

SciTech Connect

A process is described for reducing the formation of olefinic oligomer by-products and improving tertiary ether selectivity in the production of high octane alkyl tertiary alkyl ether employing acid zeolite beta catalyst particles having alpha value greater than 300, comprising: steaming or hydrothermally treating said zeolite catalyst particles at elevated temperature to provide treated acid zeolite beta catalyst particles having a reduced alpha value of less than 300; and contacting alkanol and a hydrocarbon feed stream rich in iso-olefins with said steamed or hydrothermally treated catalyst particles under iso-olefin etherification conditions sufficient to provide at least 70 weight percent conversion of said iso-olefins, whereby a product containing at least 95 weight percent of said alkyl tertiary alkyl ether is produced while the formation of olefinic oligomer-by-product is not more than 5 weight percent.

Bell, W.K.; Haag, R.O.

1993-07-06

424

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

Code of Federal Regulations, 2013 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...

2013-07-01

425

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

426

Effects of 4,4Dimethyl5,8-dihydroxynaphtalene-1-one and 4,4Dimethyl5,8-dihydroxytetralone derivatives on tumor cell respiration  

Microsoft Academic Search

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,

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

2002-01-01

427

Di-?-chlorido-?-(dimethyl sulfide)-bis-{dichlorido[(dimethyl selenide-?Se)(dimethyl sulfide-?S)(0.65/0.35)]niobium(III)}(Nb--Nb)  

PubMed Central

The dinuclear compound, [Nb2Cl6(C2H6S)1.7(C2H6Se)1.3], features an NbIII=NbIII double bond [2.6878?(5)?Å]. The mol­ecule lies on a twofold rotation axis that passes through the middle of this bond as well as through the bridging dimethyl sulfide ligand. The NbIII ion exists in an octa­hedral coordination environment defined by two terminal and two bridging Cl atoms, and (CH3)2Se/(CH3)2S ligands. The (bridging) ligand lying on the twofold rotation axis is an ordered (CH3)2S ligand, whereas the terminal ones on a general position are a mixture of (CH3)2Se and (CH3)2S ligands in a 0.647?(2):0.353?(2) ratio (the methyl C atoms are also disordered).

Matsuura, Masatoshi; Fujihara, Takashi; Nagasawa, Akira; Ng, Seik Weng

2012-01-01

428

Synthesis of Acrylates and Methacrylates from Coal-Derived Syngas.  

SciTech Connect

Research Triangle Institute (RTI), Eastman Chemical Company, and Bechtel collectively are developing a novel process for the synthesis of methyl methacrylate (MMA) from coal-derived syngas, under a contract from the U.S. Department of Energy/Federal Energy Technology Center (DOE/FETC). This three-step process consists of synthesis of a propionate, its condensation with formaldehyde, and esterification of resulting methacrylic acid (MAA) with methanol to produce MMA. Over the last quarter, RTI carried out activity tests on a pure (99 percent) Nb{sub 2}O{sub 5} catalyst, received from Alfa Aesar, under the following experimental conditions: T=300 C; P=4 atm, 72:38:16:4:220 mmol/h, PA:H{sub 2}0:HCHO:CH{sub 3}0H:N{sub 2}; 5-g catalyst charge. For the pure material, the MAA yields (based on HCHO and PA) were at 8.8 and 1.5 percent, clearly inferior compared to those for a 10-percent Nb{sub 2}O{sub 5}/Si0{sub 2} catalyst (20.1 and 4.5 percent). The X-ray diffraction (XRD) patterns of pure Nb{sub 2}O{sub 5} and 20-percent Nb{sub 2}O{sub 5}/Si0{sub 2} that while pure Nb{sub 2}O{sub 5} is very highly crystalline, Si0{sub 2} support for an amorphous nature of the 20 percent Nb{sub 2}O{sub 5}/Si0{sub 2} catalyst the last quarter, RTI also began research on the use of dimethyl ether (DME), product of methanol dehydrocondensation, as an alternate feedstock in MMA synthesis. As a result, formaldehyde is generated either externally or in situ, from DME, in the process envisaged in the contract extension. The initial work on the DME extension of the contract focuses on a tradeoff analysis that will include a preliminary economic analysis of the DME and formaldehyde routes and catalyst synthesis and testing for DME partial oxidation and condensation reactions. Literature guides exist for DME partial oxidation catalysts; however, there are no precedent studies on catalyst development for DME-methyl propionate (MP) condensation reactions, thereby making DME-MP reaction studies a challenge. The design of a fixed-bed microreactor system for DME feedstock studies was also finalized over the last quarter. The system is designed to be operated either in DME partial oxidation mode (for formaldehyde synthesis) or DME-MP condensation mode (for MMA synthesis).

Gogate, M.R.; Spivey, J.J.; Zoeller, J.R.; Colberg, R.D.; Choi, G.N.; Tam, S.S.

1997-10-17

429

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.

Vinogradova, Olga

2008-01-01

430

40 CFR 721.7046 - Formaldehyde, polymer with substituted phenols, glycidyl ether.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 false Formaldehyde, polymer with substituted phenols, glycidyl ether...Substances § 721.7046 Formaldehyde, polymer with substituted phenols, glycidyl ether...substance identified as formaldehyde, polymer with substituted phenols,...

2010-07-01

431

Synthesis of Bis(8-aminoquinoline)-substituted Tetraazacrown Ethers by a Reductive Amination Process.  

National Technical Information Service (NTIS)

Four new tetraazacrown ethers containing two 8-aminoquinoline side arms were prepared first by reductive amination of 8-nitroquinolin-2- carboxaldehyde with the appropriate tetraazacrown ether containing two NH functions (see our Technical Report No. 4). ...

Z. Yang J. S. Bradshaw P. B. Savage K. E. Krakowiak R. M. Izatt

1999-01-01

432

Synthesis of benzyl\\/allyl alkyl ethers from corresponding magnesium alkoxides  

Microsoft Academic Search

In the presence of iodine, alcohols react with magnesium to produce magnesium alkoxides which are then treated with benzyl chloride or allyl bromide to produce benzyl alkyl ethers or allyl alkyl ethers.

Ji-Mao Lin; Hui-Hui Li; Ai-Min Zhou

1996-01-01

433

Bis(chlorido)(dimethyl-sulfoxide-?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.

Gschwind, Fabienne; Jansen, Martin

2012-01-01

434

Destruction of dimethyl methylphosphonate using a microwave plasma torch  

NASA Astrophysics Data System (ADS)

A microwave plasma torch with a microwave power of 1.2 kW destroys dimethyl methylphosphonate (DMMP) with a destruction rate of 1.14 l/h, demonstrating a safe removal capability of stockpiled chemical weapons. The FTIR spectra of the discharge gas from DMMP destruction indicates near perfect elimination of DMMP when the proper amount of oxygen gas is added. This can be confirmed by the gas chromatography spectra, which show the disappearance of even intermediary compounds. The compactness and light weight of the microwave plasma torch provide an effective means of on-site removal of the chemical warfare agents found on a battlefield.

Uhm, Han S.; Cho, Soon C.; Hong, Yong C.; Park, Yang G.; Park, Ju S.

2008-02-01

435

Bis(chlorido)(dimethyl-sulfoxide-?O)barium(II).  

PubMed

The title compound, [BaCl(2)(C(2)H(6)SO)], forms a Ba(6)Cl(9) cluster in which the BaCl(2) units are connected via dimethyl-sulfoxide (DMSO) and chloride bridges. The central Cl atom of the Ba(6)Cl(9) cluster is located on a threefold inversion axis and is coordinated octa-hedrally to six barium cations. In the crystal, the clusters are arranged in rows, which are inter-connected by the DMSO mol-ecules, forming a three-dimensional network. PMID:23284316

Gschwind, Fabienne; Jansen, Martin

2012-11-01

436

Comparison of global climatological maps of sea surface dimethyl sulfide  

NASA Astrophysics Data System (ADS)

We have examined differences in regional and seasonal variability among seven global climatologies of sea-surface dimethyl sulfide (DMS) concentrations. We found large differences between recent climatologies and that typically used by most atmospheric sulfur models. The relative uncertainty (1?/mean) in the latitudinal distribution of the annual mean DMS concentration increases from about 50% in tropical and temperate regions to nearly 100% in the high latitudes. We also compared these climatologies to new measurements in the North Atlantic Ocean taken during the 2001 Programme Océan Multidisciplinaire Méso Echelle (POMME) expeditions.

Belviso, S.; Bopp, L.; Moulin, C.; Orr, J. C.; Anderson, T. R.; Aumont, O.; Chu, S.; Elliott, S.; Maltrud, M. E.; Simó, R.

2004-09-01

437

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

438

Low temperature synthesis of ionic phosphates in dimethyl sulfoxide.  

PubMed

A new synthesis route for phosphates in an organic solvent at low temperatures is presented. The synthesis was done by dispersing a nitrate salt and phosphorus pentoxide in dimethyl sulfoxide. The synthesis can be performed under water-free conditions and yielded several organic and inorganic phosphates. Crystal structure solution of bistetramethylammonium hydrogencyclotriphosphate, [N(CH3)4]2HP3O9, was achieved by combining information gained from powder X-ray diffraction, liquid NMR and solid state (2D) NMR. The molecular structure of rubidium cyclotetraphosphate, Rb4P4O12, was determined using liquid state NMR and solid state (2D) NMR spectroscopy. PMID:24865226

Mangstl, Martin; Celinski, Vinicius R; Johansson, Sebastian; Weber, Johannes; An, Feng; Schmedt Auf der Günne, Jörn

2014-07-14

439

N,N-Dimethyl-N?,N??-diphenyl-phospho-ric triamide  

PubMed Central

In the title compound, C14H18N3OP, a crystallographic mirror plane bis­ects the mol­ecule (the C,N,C atoms of the dimethyl­amido moiety and the P=O unit lie on the mirror plane). The P atom has a distorted tetra­hedral geometry; the bond angles at P are in the range 98.98?(11)–115.28?(7)°. In the crystal, the O atom of the P=O group acts as a double hydrogen-bond acceptor for two symmetry-equivalent N—H?O hydrogen bonds, building [001] chains containing R 2 1(6) loops.

Pourayoubi, Mehrdad; Yousefi, Mohammad; Eslami, Farnaz; Rheingold, Arnold L.; Chen, Chao

2011-01-01

440

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

Microsoft Academic Search

Oxygenates, mainly methyl tert-butyl ether (MTBE), are commonly added to gasoline to enhance octane index and improve combustion efficiency. Other oxygenates used as gasoline additives are ethers such as ethyl tert-butyl ether (ETBE), tert-amyl methyl ether (TAME), and alcohols such as tert-butyl alcohol (TBA). As a result of its wide use, MTBE has been detected, mainly in the USA, in

F. Fayolle; J.-P. Vandecasteele; F. Monot

2001-01-01

441

Reactions between vinyl compounds and multifunctional compounds communication 1. Reactions of alkyl vinyl ethers with glycerol  

Microsoft Academic Search

Summary 1. A study has been mark of the reactions of ethyl vinyl ether and of butyl vinyl ether with glycerol in pressure of these of hydrogen chloride, the reactants being taken in equimolecular proportions. The main reaction products were 1,2- and 1,3-O-ethylidineglycerol from ethyl vinyl ether and 1,2-O-ethylideneglycerol from butyl vinyl ether. 2. The formation of 1,2- and 1,3-O-ethylideneglycerols

M. F. Shostakovsky; V. V. Zhebrovsky; M. A. Medelyanovskaya

1954-01-01

442

The Use of tertButyl Vinyl Ether in Stepwise Electrophilic Addition Reactions  

Microsoft Academic Search

tert-Butyl vinyl ether (1) reacts with p-TolSCl to give 2-tert-butoxy-2-chloroethyl p-tolyl sulfide (2). In the presence of SnCl4, 2 reacts with silyl enol ethers, allyltrimethylsilane, and vinyl ethers to form a C-C bond. In the case of vinyl ethers, the reaction proceeds through the formation of the 5-membered sulfonium salt intermediate which in turn can react with H2O, TMSCN, allyltrimethylsilane,

Leonid N. Koikov; Mingming Han; Dawn M. Wellman; Jim A. Kelly; Irina P. Smoliakova

2000-01-01

443

Biomodification of thermosensitive copolymer of ethylene glycol vinyl ether by RGD and insulin  

Microsoft Academic Search

The radiation copolymerization of hydrophilic vinyl ether monomer, ethylene glycol vinyl ether (EGVE), and hydrophobic comonomer butyl vinyl ether (BVE) was realized in the presence of crosslinking agent diethylene glycol divinyl ether. The results of swelling experiments indicated that the hydrogel which has 60:40 comonomer ratio (mole percentage of EGVE:BVE in monomeric mixture) is temperature-sensitive at 4–37 °C temperature range.

Menem?e Gümü?derelio?lu; Ok?en Müftüo?lu; Ay?e Gönen Karakeçili

2004-01-01

444

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

445

Biochemical effects of methyl tertiary -butyl ether in extended vapour exposure of rats  

Microsoft Academic Search

Male Wistar rats exposed to 50, 100 or 300 ppm methyl tertiary-butyl ether vapour for 2–15 weeks, 6 h daily, 5 days a week, showed a dose-dependent blood ether concentration after 2 weeks' exposure. Blood concentrations of teriary-butanol, were also dose dependent indicating metabolic breakdown of the ether in vivo. The blood ether concentrations decreased after 6 weeks of exposure

H. Savolainen; Pirkko Pffiffli; Eivor Elovaara

1985-01-01

446

Synthesis and characterization of novel ionophores of double-armed penta-crown ethers  

Microsoft Academic Search

Unique structures of novel ionophores of double-armed penta-crown ethers were successfully synthesized. Diaza 18-crown-6 was designed as the parent crown ring. The penta-crown ethers were prepared by the reaction of trimethylolpropane triacrylate (TMPTA) with diaza 18-crown-6 and further with 1-aza crown ethers through the Michael reaction. The newly synthesized penta-crown ethers were characterized by 1H NMR, 13C NMR, FAB mass

Zhi Bin Huang; Seung Hyun Chang

2005-01-01

447

Cure kinetics, morphological and dynamic mechanical analysis of diglycidyl ether of bisphenol-A epoxy resin modified with hydroxyl terminated poly(ether ether ketone) containing pendent tertiary butyl groups  

Microsoft Academic Search

Hydroxyl terminated poly(ether ether ketone) based on tert-butyl hydroquinone (PEEKTOH) was used to modify a diglycidyl ether of bisphenol-A epoxy resin. A diamine, 4,4?-diaminodiphenylsulfone was used as the curing agent. Isothermal differential scanning calorimetric measurements of the blends were carried out at 180, 165 and 150°C. The extent of reaction was found to decrease with the addition of PEEKTOH. The

Bejoy Francis; V. Lakshmana Rao; Geert Vanden Poel; Fabrice Posada; Gabriel Groeninckx; R. Ramaswamy; Sabu Thomas

2006-01-01

448

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

Microsoft Academic Search

Methyl tert-butyl ether (MTBE), ethyl tert-butyl ether (ETBE) and tert-amyl methyl ether (TAME) are oxygenated compounds added to gasoline to enhance octane rating and to improve combustion. They may be found as pollutants of living and working environments. In this work a robotized method for the quantification of low level MTBE, ETBE and TAME in human urine was developed and

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

2007-01-01

449

Reactions of unsaturated and macromolecular compounds Communication 5. Copolymerization of methyl acrylate with vinyl ethers  

Microsoft Academic Search

Summary 1.The conditions required for the copolymerization of methyl acrylate with ethyl, butyl, and phenyl vinyl ethers have been studied. Copolymers of methyl acrylate with ethyl, butyl, and phenyl vinyl ethers have been prepared.2. It has been shown that the composition of the copolymers obtained depends on the concentrations of vinyl ethers and methyl acrylate in the given reation mixtures.3.Copolymers

M. F. Shostakovsky; A. M. Khomutov

1955-01-01

450

ONE-POT CLAISEN REARRANGEMENT WITH N-BUTYL VINYL ETHER  

Microsoft Academic Search

A protocol for one-pot Claisen rearrangement with n-butyl vinyl ether is described. Upon heating allylic alcohols with excess n-butyl vinyl ether with catalytic amount of Hg(OAc)2 and NaOAc, Claisen rearrangement takes place through in situ formation of the requisite allyl vinyl ether.

Hidetoshi Tokuyama; Takaki Makido; Toshihiro Ueda; Tohru Fukuyama

2002-01-01

451

Survey of Ethylene Glycol Ether Exposures in Belgian Industries and Workshops  

Microsoft Academic Search

From 1983 onward, 2654 air samples from 336 different plants from the northern part of Belgium were analyzed for the presence of ethylene glycol ethers. One or more ethylene glycol ethers were detected in 262 air samples (9.9%) covering 78 plants or small establishments (23.2%) from a wide variety of industries. Ethylene glycol ethers were mainly present in establishments or

H. VEULEMANS; D. H. Groeseneken; R. MASSCHELEIN; E. V. van Vlem

1987-01-01

452

Glove Permeation by Propylene Glycol Monomethyl Ether Acetate — A Photoresist Solvent Used in Semiconductor Device Processing  

Microsoft Academic Search

Propylene glycol monomethyl ether acetate (PGMEA) has been introduced as a replacement solvent for ethylene glycol ethers and ether acetates in photoresist formulations used in semiconductor processing. While PGMEA does not exhibit the adverse reproductive health effects found with the structurally related ethylene glycol derivatives, it is nevertheless readily absorbed through the skin, and proper protection against dermal absorption is

Edward T. Zellers; Robert Sulewski

1992-01-01

453

New Aromatic Activated Dihalides and Bisphenol Monomers for the Preparation of Novel Poly(Arylene Ethers).  

National Technical Information Service (NTIS)

The goal of this research program was to synthesize a series of unique monomers of type I to be utilized at NASA-Langley in the preparation of new poly(arylene ether ketones), poly(arylene ether ketosulfones), and poly(arylene ether ketophosphine oxides)....

J. F. Wolfe

1993-01-01

454

EVALUATION OF THE POTENTIAL CARCINOGENICITY OF CHLOROMETHYL METHYL ETHER (TECHNICAL GRADE)  

EPA Science Inventory

Technical grade chloromethyl methyl ether is contaminated with between 1 and 8 percent bis(chloromethyl)ether, which is a known human carcinogen. ence, the human evidence for this compound and the hazard ranking are based on the evidence for bis(chloromethyl) ether. echnical grad...

455

Poly(aryl ether amides): Self polymerization of an AB monomer via amide-activated ether synthesis  

Microsoft Academic Search

Summary  A synthetic approach for the preparation of poly(aryl ether amides) has been developed where the generation of an aryl ether\\u000a linkage was the polymer-forming reaction. The amide moiety was found to be sufficiently electron withdrawing to activate halosubstituents,\\u000a towards nucleophilic aromatic substitution polymerizations, analogous to conventional activating groups (i.e, sulfone, ketone\\u000a etc.). Several new A-B monomers, 4-fluoro-N-(4-hydroxyphenyl)benzamide, 1, and 4-fluoro-N-(3-hydroxyphenyl)benzamide,

M. Lucas; J. L. Hedrick

1992-01-01

456

Novel soluble aromatic poly(ether amide sulfone amide ether ketone ketone)s by electrophilic solution polycondensation  

Microsoft Academic Search

A new monomer, N,N '-bis(4-phenoxybenzoyl)-4,4'-diaminodiphenyl sulfone (BPBDAS), was prepared by the condensation of 4,4'-diaminodiphenyl sulfone with 4-phenoxybenzoyl chloride in N,N-dimethylacetamide. Novel soluble aromatic poly(ether amide sulfone amide ether ketone ketone)s (PEASAEKKs) were synthesized by electrophilic solution copolycondensation of BPBDAS with a mixture of terephthaloyl chloride and isophthaloyl chloride in the presence of anhydrous aluminum chloride and N-methylpyrrolidone in 1,2-dichloroethane. The

Nengwen Ding; Mengfei Chen; Mingzhong Cai

2011-01-01

457

Solvent-Induced Frequency Shifts in the Infrared Spectrum of Dimethyl Sulfoxide in Organic Solvents.  

National Technical Information Service (NTIS)

Solvent-induced frequency shifts in the infrared spectrum of dimethyl sulfoxide (DMSO)and deuterated dimethyl sulfoxide (DMSO-d6) as dilute solutes have been studied in a wide variety of organic solvents. The results obtained show that intermolecular inte...

W. R. Fawcett A. A. Kloss

1996-01-01

458

The formation of malodorous dimethyl oligosulphides in treated groundwater: the role of biofilms and potential precursors  

Microsoft Academic Search

Water distributed from the Wanneroo Groundwater Treatment Plant intermittently contains dimethyl trisulphide (DMTS). The compound is responsible for a “swampy odour” in the water. DMTS production from potential precursors was insignificant in the absence of biofilms when compared with DMTS production from precursors in the presence of biofilms in a biofilm reactor. Greatest dimethyl disulphide (DMDS) and DMTS production (>3000ngL?1

Peter D Franzmann; Anna Heitz; Luke R Zappia; Johannes E Wajon; Kevin Xanthis

2001-01-01

459

Microbial Activity in Aquatic Environments Measured by Dimethyl Sulfoxide Reduction and Intercomparison with Commonly Used Methods  

Microsoft Academic Search

A new method to determine microbial (bacterial and fungal) activity in various freshwater habitats is described. Based on microbial reduction of dimethyl sulfoxide (DMSO) to dimethyl sulfide (DMS), our DMSO reduction method allows measurement of the respiratory activity in interstitial water, as well as in the water column. DMSO is added to water samples at a concentration (0.75% (vol\\/vol) or

CHRISTIAN GRIEBLER; DORIS SLEZAK

2001-01-01

460

Coupling reaction and azeotropic distillation for the synthesis of glycerol carbonate from glycerol and dimethyl carbonate  

Microsoft Academic Search

A new process, coupling reaction and azeotropic distillation was proposed for the synthesis of glycerol carbonate (GC) from glycerol (G) and dimethyl carbonate (DMC). The bench scale experimental investigation was systematically conducted for this new process. With calcium oxide (CaO) as the solid catalyst, the high yield of glycerol carbonate can be obtained at a low molar ratio of dimethyl

Jiabo Li; Tao Wang

2010-01-01

461

40 CFR 721.10159 - 1-Docosanamine, N,N-dimethyl-.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false 1-Docosanamine, N,N-dimethyl-. 721.10159 Section 721.10159 Protection...Specific Chemical Substances § 721.10159 1-Docosanamine, N,N-dimethyl-. (a) Chemical substance and...

2013-07-01

462

Hydrogenation of 2,5-dimethyl-4-phenyl(p-alkylbenzyl) pyridines over metal sulfides  

Microsoft Academic Search

The corresponding substituted piperidines were obtained in yields from 40 to 99.5% by the hydrogenation of 2,5-dimethyl-4-phenylpyridine and 2,5-dimethyl-4-[p-methyl(p-ethyl)benzyl]pyridines in the presence of rhenium, platinum, and palladium sulfides.

M. A. Ryashentseva; Kh. M. Minachev; Vo V. Dorogov; N. S. Prostakov

1972-01-01

463

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

464

Hydrolysis of succinic acid dimethyl ester in rat pancreatic islets.  

PubMed

The hydrolysis of the dimethyl ester of [1,4-14C]succinic acid and/or [2,3-14C]succinic acid was measured in homogenates of rat pancreatic islets, liver, jejunum, brain, BC3H1 mouse myocytes, NG108-19 mouse neuroblastoma x rat glioma hybrid cells, and Caco-2 human colon adenocarcinoma cells. The specific activity of the enzyme was much higher in liver, jejunum, and Caco-2 cells than in the other cell types. The affinity of the enzyme for succinic acid dimethyl ester (SAD) was also much higher in liver than in islet homogenates. In the latter case, both particulate and cytosolic activity were observed upon subcellular fractionation. The activity found in islet homogenates was commensurate with the rate of SAD hydrolysis in intact cells. While the intracellular pool of acidic metabolites generated from SAD remained fairly stable over a 15- to 120-min incubation and was mainly located in the cytosolic compartment, the amount of acidic metabolites released in the extracellular milieu progressively increased with the length of incubation. Such metabolites included both monocarboxylic and dicarboxylic acids, the latter consisting mainly of succinic acid and, to a much lesser extent, of fumaric acid and malic acid. However, at variance with SAD, succinic acid failed to be taken up by intact islets. There was no close parallelism between the specific activity of the SAD esterase and the extent of SAD utilization in distinct cell types. PMID:7582870

Zhang, T M; Sener, A; Malaisse, W J

1995-08-01

465

Mediated electrochemistry of dimethyl sulfoxide reductase from Rhodobacter capsulatus.  

PubMed

Electrochemically driven catalysis of the bacterial enzyme dimethyl sulfoxide (DMSO) reductase (Rhodobacter capsulatus) has been studied using the macrocyclic complex (trans-6,13-dimethyl-1,4,8,11-tetraazacyclotetradecane-6,13-diamine)cobalt(III) as a mediator. In the presence of both DMSO and DMSO reductase, the normal transient Co(III/II) voltammetric response of the complex is transformed into an amplified and sigmoidal (steady-state) waveform characteristic of a catalytic EC' mechanism. At low concentrations of DMSO (approximately K (M)) or high mediator concentrations (more than the concentration of DMSO reductase), the steady-state character of the voltammetric response disappears and is replaced by more complicated waveforms that are a convolution of transient and steady-state behavior as different steps within the catalytic cycle become rate limiting. Through digital simulation of cyclic voltammetry performed under conditions where the sweep rate, DMSO concentration, DMSO reductase concentration and mediator concentration were varied systematically, we were able to model all voltammograms with a single set of rate and equilibrium constants which provide new insights into the kinetics of the DMSO reductase catalytic mechanism that have hitherto been inaccessible from steady state or stopped flow kinetic studies. PMID:19082848

Chen, Kuan-I; McEwan, Alastair G; Bernhardt, Paul V

2009-03-01

466

High-Temperature Stabilization of Polyphenyl Ethers by Inorganic Salts.  

National Technical Information Service (NTIS)

The free radical-induced high-temperature (to ca 370 C) oxidative degradation of polyphenyl ethers is shown to be drastically curtailed by the oxides, hydroxides and carbonates (but not the neutral salts) of the alkali metals and barium. The inhibiting en...

H. Ravner W. B. Moniz C. H. Blachly

1972-01-01

467

New MTBE design now commercial. [Methyl tertiary butyl ether  

Microsoft Academic Search

MTBE is considered by many to be the most promising octane booster to replace lead in gasoline during the 1980s. MTBE (methyl tetriary butyl ether) is made by combining methanol and isobutylene. The economic attractiveness for making this gasoline component is greatly improved by using a patented catalyst support system to give simultaneous reaction and distillation in a standard carbon

L. A. Smith; M. N. Huddleston

1982-01-01

468

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

469

Laser-induced multiphoton dissociation of n-butyl ether  

NASA Astrophysics Data System (ADS)

The pulsed CO 2-laser-induced multiphoton dissociation of n-butyl vinyl ether is studied. Comprehensive measurements have been performed for 9.6.?m and 10.6 ?m irradiation. The corresponding dissociation product distributions show distinct differences for the two irradiation wavelengths, the most important finding being that acetylene is only produced at 9.6 ?m.

Hofmann, Hubert; Kl?ffer, Waiter; Sch?fer, Gerhard; Gloor, Jean

1981-04-01

470

Exposure assessment of polybrominated diphenyl ethers (PBDEs) in Mexican children  

Microsoft Academic Search

Flame retardants (FRs) constitute a group of compounds that are added to materials in order to suppress, reduce, or delay fire. At present the most used FRs are the polybrominated diphenyl ethers (PBDEs), and diverse studies have found individuals exposed to them. However, few studies have reported data in children. The objective of this report was to assess PBDEs levels

Iván N. Pérez-Maldonado; María del Rocio Ramírez-Jiménez; Laura P. Martínez-Arévalo; O. Dania López-Guzmán; Maria Athanasiadou; Åke Bergman; Mario Yarto-Ramírez; Arturo Gavilán-García; Leticia Yáñez; Fernando Díaz-Barriga

2009-01-01

471

Acute and subchronic toxicity of ethylene glycol monobutyl ether  

Microsoft Academic Search

The available information on the acute and subchronic toxicity of ethylene glycol monobutyl ether is reviewed. Data from animal studies have been examined from the standpoint of dose-response relationships and the sensitivity of various animal species (rats, guinea pigs, mice, dogs, rabbits), including man, to the effects of this chemical. In view of recent findings with other chemically related glycol

Tyler

1984-01-01

472

Diphytanyl and dibiphytanyl glycerol ether lipids of methanogenic archaebacteria  

Microsoft Academic Search

The lipids of nine different methanogenic bacterial strains are comprised of diphytanyl glycerol diethers, previously known only in extremely halophilic bacteria, as well as dibiphytanyl diglycerol tetraethers, known formerly only in the extremely thermoacidophilic bacteria Thermoplasma and Sulfolobus. Of the methanogens examined from four representative taxonomic groups, Methanobacterium and Methanospirillum contained both types of isopranyl ethers in nearly equal proportions,

T. G. Tornabene; T. A. Langworthy

1979-01-01

473

Methyl substituted polyimides containing carbonyl and ether connecting groups  

NASA Technical Reports Server (NTRS)

Polyimides were prepared from the reaction of aromatic dianhydrides with novel aromatic diamines having carbonyl and ether groups connecting aromatic rings containing pendant methyl groups. The methyl substituent polyimides exhibit good solubility and form tough, strong films. Upon exposure to ultraviolet irradiation and/or heat, the methyl substituted polyimides crosslink to become insoluble.

Hergenrother, Paul M. (inventor); Havens, Stephen J. (inventor)

1992-01-01

474

Exploring Crown Ethers as Shift Reagents for Ion Mobility Spectrometry  

PubMed Central

A series of crown ethers, 12-crown-4, 15-crown-5, 18-crown-6, and dibenzo-30-crown-10, are examined as a possible means of shifting the mobilities of peptide ions. In this approach, a crown ether is added to a solution containing a mixture of peptides and is electrosprayed into the gas phase in order to create distributions of peptide-crown complexes. The ion complexes have different mobilities than the naked peptide ions, and the crown ether molecules appear to interact specifically with basic sites in the peptides thus providing some sequence selectivity. After the peptide-crown complexes are separated by ion mobility spectrometry, the ions can be collisionally activated to dissociate the complex (forming the naked peptide ions) prior to m/z analysis. The overall effect is that complex formation shifts peptide ions to different regions of the mobility spectrum, extending the ability to resolve components. The approach is illustrated by examining isobaric dipeptides as well as a combinatorial library containing 27 tripeptides. Cross sections for the series of crown ether ions and complexes that are observed are reported.

Hilderbrand, Amy E.; Myung, Sunnie; Clemmer, David E.

2008-01-01

475

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

476

Methanol for moter fuel via the ethers route  

Microsoft Academic Search

The simplest means to blend methanol into gasoline is to indirectly transform it into ethers by reaction with olefins contained in the Câ and gasoline fractions. The need to investigate nonpetroleum-derived compounds is due to federal measures to reduce polluting emissions and to progressively suppress lead alkyl additives. Tables give octane of typical refinery streams and economics of MTBE-TAME (and

B. Torck; A. Chauvel; A. Convers

1982-01-01

477

Metal-Ion Complexation by Ionic Crown Ethers.  

National Technical Information Service (NTIS)

During the second year of the DOE-funded project, rapid progress has been made in three areas: the synthesis of crown ethers which possess pendant carboxylic acid groups; the selectivity and efficiency for solvent extraction of alkali metal and of alkalin...

R. A. Bartsch

1981-01-01

478

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.

Xiong, Yuan; Schaus, Scott E.

2013-01-01

479

Condensation of perfluoroisobutylene with perfluorinated vinyl alkyl ethers  

SciTech Connect

Condensation of perfluoroisobutylene with perfluorovinyl aklyl ethers with CsF catalysis takes place according to a scheme of concerted nucleophilic addition, with participation of the perfluoro-tert-butyl anion as nucleophile and perfluoroisobutylene as electrophile. In the presence of CO/sub 2/ the product of concerted perfluoroalkylcarboxylation forms.

Postovoi, S.A.; Zeifman, Yu.V.; Knunyants, I.L.

1986-12-10

480

Methyl tert-butyl ether (MTBE) bioremediation studies  

Microsoft Academic Search

The massive production of methyl tert-butyl ether (MTBE), a primary con- stituent of reformulated gasoline, combined with its mobility, persistence and toxicity, makes it an important pollutant. It was considered recalcitrant until a few years ago, but recently MTBE biodegradation in aerobic conditions has been demonstrated with both mixed and pure cultures. Mixed cultures are generally the more effective for

E. ZANARDINI; C. PISONI; G. RANALLI; M. ZUCCHI; C. SORLINI

481

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

482

The epistemic view of quantum states and the ether  

NASA Astrophysics Data System (ADS)

The idea that the wave function represents information, or knowledge, rather than the state of a microscopic object has been held to