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1

Development of Low-NOx Emission DME (Dimethyl Ether) Combustor  

NASA Astrophysics Data System (ADS)

This study focuses on fundamental characteristics of DME (Dimethyl Ether) combustion, aiming at the development of low-NOx combustion. DME is one of the most promising new alternative fuels owing to its cleanness of the exhaust gas and wide applications. Combustion experiments using a diffusion burner were conducted for characterizing DME through the comparison with the results of LPG and 13A-city gas. Experimental results demonstrated a high potential of DME for a boiler and a gas-turbine fuel. DME has a wide stable-combustion range compared with those of the other fuels. In this study, the concept of the low-NOx combustion, referred to as the tube-nested combustion, was applied to the DME combustion. This tube-nested combustor consists of tube banks to cool the burning flame leading to NOx reduction. Then, the NOx emission of the DME combustion was successfully reduced to a level suitable for practical applications.

Matsumoto, Ryosuke; Ishihara, Isao; Ozawa, Mamoru; Imahori, Keizo

2

DIMETHYL ETHER (DME)FUELED SHUTTLE BUS DEMONSTRATION PROJECT  

Microsoft Academic Search

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

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

2003-01-01

3

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. The strategy is to blend DME with diesel fuel, to obtain the necessary lubricity to protect the fuel injection system and to achieve low emissions. Within the Combustion Laboratory of the Penn State Energy Institute, they have installed and equipped a Navistar V-8 direct-injection turbodiesel engine for measurement of gaseous and particulate emissions and examination of the impact of fuel composition on diesel combustion. They have also reconfigured a high-pressure viscometer for studies of the viscosity, bulk modulus (compressibility) and miscibility of blends of diesel fuel, dimethyl ether and lubricity additives. The results include baseline emissions, performance and combustion measurements on the Navistar engine for operation on a federal low sulfur diesel fuel (300 ppm S). Most recently, they have examined blends of an oxygenated fuel additive (a liquid fuel called CETANER{trademark}) produced by Air Products, for comparison with dimethyl ether blended at the same weight of oxygen addition, 2 wt.%. While they have not operated the engine on DME yet, they are now preparing to do so. A fuel system for delivery of DME/Diesel blends has been configured and initial investigations at low DME blend ratios (around 5-10 vol%) will begin shortly. They have also performed viscosity measurements on diesel fuel, DME and 50-50 blends of DME in diesel. These tests have verified that DME has a much lower viscosity than the diesel fuel and that the viscosity of the blended fuel is also much lower than the diesel base fuel. This has implications for the injection and atomization of the DME/diesel blends.

Elana M. Chapman; Shirish Bhide; Andre L. Boehman; David Klinikowski

2003-04-01

4

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. The strategy is to blend DME with diesel fuel, to obtain the necessary lubricity to protect the fuel injection system and to achieve low emissions. The laboratory studies have included work with a Navistar V-8 turbodiesel engine, demonstration of engine operation on DME-diesel blends and instrumentation for evaluating fuel properties. The field studies have involved performance, efficiency and emissions measurements with the Champion Motorcoach ''Defender'' shuttle bus which will be converted to DME-fueling. The results include baseline emissions, performance and combustion measurements on the Navistar engine for operation on a federal low sulfur diesel fuel (300 ppm S). Most recently, they have completed engine combustion studies on DME-diesel blends up to 30 wt% DME addition.

Elana M. Chapman; Shirish Bhide; Jennifer Stefanik; Andre L. Boehman; David Klinikowski

2003-04-01

5

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

6

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 dimethylether. 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. The strategy is to blend DME with diesel fuel, to obtain the necessary lubricity to protect the fuel injection system and to achieve low emissions. 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 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 operation 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 have continued as it has been difficult to maintain operability of the shuttle bus due to fuel and component difficulties. As of late June 2002, it appears that 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 is being installed on the system to alleviate this problem and get the shuttle bus back in operation. In summary, the conversion is completed but there have been operational challenges in the field. They continue to work to make the shuttle bus as reliable to operate on DME-diesel blends as possible.

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

2003-04-01

7

Synthesis of dimethyl ether (DME) by catalytic distillation  

Microsoft Academic Search

The intrinsic kinetics of liquid phase catalytic dehydration of methanol to dimethyl ether over a macroporous sulphonic acid ion exchange resin was determined in a fixed-bed micro-reactor in the temperature range of 391–423K and pressures up to 2.0MPa. The kinetic model based on Eley–Rideal mechanism, as well as the power-rate law model, was adopted for fitting the experimental data. However,

Zhigang Lei; Zhiwu Zou; Chengna Dai; Qunsheng Li; Biaohua Chen

2011-01-01

8

Dimethyl ether (DME) from coal as a household cooking fuel in China  

E-print Network

pollution and health Combustion of solid fuels such as biomass and coal in household cooking in ChinaDimethyl ether (DME) from coal as a household cooking fuel in China Eric D. Larson Princeton be made from any carbonaceous feedstock, including natural gas, coal, or biomass, using established

9

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

NASA Astrophysics Data System (ADS)

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

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

10

Astrochemistry of dimethyl ether  

Microsoft Academic Search

Dimethyl ether (DME, CH3OCH3) is one of the largest organic molecules detected in the interstellar gas and shows high abundances in star-forming regions, known as hot molecular cores. The observed DME might be formed on grains or by secondary gas phase reactions from a precursor molecule, which in turn was sublimed into the gas phase from the grain surface. Studies

Z. Peeters; S. D. Rodgers; S. B. Charnley; L. Schriver-Mazzuoli; A. Schriver; J. V. Keane; P. Ehrenfreund

2006-01-01

11

Red-shifted and improper blue-shifted hydrogen bonds in dimethyl ether (DME) n ( n=1-4) and hydrated (DME) n ( n=1-4) clusters. A theoretical study  

NASA Astrophysics Data System (ADS)

In the present study, dimethyl ether (DME), dimethyl ether dimer (DME) 2, trimer (DME) 3, tetramer (DME) 4 and hydration of these clusters have been investigated using the ab initio and density functional theory methods. The formation of (DME) n ( n=2-4) complexes lead to the contraction of methyl C-H bond and elongation of C-O bond, when these two bonds form the hydrogen bonding. The contraction of C-H bond gives a blue shift in the C-H stretching frequency. The interaction of water molecules with the (DME) n ( n=1-4) complexes lead to the elongation of O-H bonds. The elongation of O-H bond gives the red shift in the O-H stretching frequency. The length of the C-H⋯O hydrogen bond is longer than the length of the R(O⋯H) hydrogen bond, which gives the standard O-H⋯O H-bond interaction. Interaction energies were calculated after eliminating basis set superposition error by using full counterpoise correction method. Interaction energy for the C-H⋯O hydrogen bond is less than that for the O-H⋯O hydrogen bond. Natural bond orbital analysis reveals that the increase of electron density in the ?* antibonding orbitals of the O-H bond in water yield its weakening. The contractions of C-H bond in the (DME) clusters have been analyzed using the concept of charge density transfer and rehybridization mechanisms. The charge density ( ?), and Laplacian of charge density (? 2?), were also calculated for both C-H⋯O and O-H⋯O interactions, which are used for the classification of improper (blue shifted) and proper (red shifted) hydrogen bonds.

Vijayakumar, S.; Kolandaivel, P.

2005-01-01

12

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

13

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

14

Modeling, simulation and control of dimethyl ether synthesis in an industrial fixed-bed reactor  

Microsoft Academic Search

Dimethyl ether (DME) as a clean fuel has attracted the interest of many researchers from both industrial communities and academia. The commercially proven process for large scale production of dimethyl ether consists of catalytic dehydration of methanol in an adiabatic fixed-bed reactor. In this study, the industrial reactor of DME synthesis with the accompanying feed preheater has been simulated and

M. Farsi; R. Eslamloueyan; A. Jahanmiri

2011-01-01

15

Synthesis of methyl acetate from syngas via dimethyl ether  

SciTech Connect

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

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

1999-07-01

16

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

E-print Network

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

Iglesia, Enrique

17

Syngas to olefins via dimethyl ether over zeolite catalysts  

SciTech Connect

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

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

1998-12-31

18

Performance of a controllable premixed combustion engine fueled with dimethyl ether  

Microsoft Academic Search

This paper presents a new concept of the controllable premixed combustion (CPC) for an internal combustion engine fueled with dimethyl ether (DME). The CPC system is composed of an electronic control low pressure injection system, a premix chamber and a main chamber. Between the two chambers, a control valve is set. DME is entirely injected into the premix chamber at

Jun Song; Zhen Huang; Xinqi Qiao; Wanli Wang

2004-01-01

19

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

20

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

PubMed Central

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

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

2014-01-01

21

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

PubMed

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

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

2014-10-01

22

Wide range modeling study of dimethyl ether oxidation  

SciTech Connect

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

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

1997-04-01

23

Multinuclear magnetic resonance studies of gaseous and liquid dimethyl ethers  

NASA Astrophysics Data System (ADS)

Dimethyl ethers (DME): (CH 3) 2O, CH 3OCD 3, (CD 3) 2O have been studied using advanced NMR spectroscopy in liquid and gaseous states at 300 K. Extrapolation of the gas-phase results to the zero-density limit permitted the measurements of 1H, 13C and 17O nuclear magnetic shieldings of isolated DME molecules. The significance of intermolecular effects in the gaseous state as well as by coming from gas to liquid are also reported; measured gas-to-liquid shifts for 13C and 17O nuclei are negative (deshielding effects) but positive for 1H nuclei. The very weak linear dependence on density has also been observed for the carbon-proton and carbon-deuteron scalar coupling constants over one bond in the appropriate methyl group of DME. It was possible to obtain the coupling constants free from intermolecular interactions: 1J0(CH)=138.84 Hz in (CH 3) 2O, 1J0(CH)=138.81 Hz and 1J0(CD)=21.17 Hz in CH 3OCD 3 and 1J0(CD)=21.16 Hz in (CD 3) 2O. The magnitude of isotope effects on nuclear shieldings and indirect coupling constants caused by H/D substitution is also discussed. These new experimental results are suitable for a better verification of ab initio calculations of indirect coupling constants and nuclear magnetic shieldings of all nuclei in molecules under study.

Makulski, W?odzimierz

2005-06-01

24

Separation of dimethyl ether from syn-gas components by poly(dimethylsiloxane) and poly(4-methyl-1-pentene) membranes  

Microsoft Academic Search

Dimethyl ether (DME) has been discussed as a potential fuel for both combustion and fuel cell applications. This paper evaluates the ability for membranes to separate DME from syn-gas components, such as H2 and CO. Separations from CO2 and CH4 also are discussed. Experiments performed include permeability and selectivity of these gases through poly(4-methyl-1-pentene) (TPX) and poly(dimethylsiloxane) (PDMS) using variable

Christopher J. Orme; Frederick F. Stewart

2011-01-01

25

A laser and molecular beam mass spectrometer study of low-pressure dimethyl ether flames  

SciTech Connect

The oxidation of dimethyl ether (DME) is studied in low-pressure flames using new molecular beam mass spectrometer and laser diagnostics. Two 30.0-Torr, premixed DME/oxygen/argon flames are investigated with stoichiometries of 0.98 and 1.20. The height above burner profiles of nine stable species and two radicals are measured. These results are compared to the detailed chemical reaction mechanism of Curran and coworkers. Generally good agreement is found between the model and data. The largest discrepancies are found for the methyl radical profiles where the model predicts qualitatively different trends in the methyl concentration with stoichiometry than observed in the experiment.

Andrew McIlroy; Toby D. Hain; Hope A. Michelsen; Terrill A. Cool

2000-12-15

26

Generation Performance of a Fuel Cell Using Hydrogen and Di-methyl-ether (DME) Mixed Gas  

NASA Astrophysics Data System (ADS)

Di-methyl-ether (DME), an oxygenated hydrocarbon, can facilitate hydrogen manufacture by steam reforming reaction at low temperature. Methanol and DME steam reforming at 250-300°C, reforming DME into hydrogen, can be performed easily with small-scale and simple equipment. Whether the hydrogen output from the reformer for supply to the fuel cell includes DME, and how this affects the generation performance has yet to be confirmed. The purpose of this paper is to investigate the supply of a fuel cell with mixtures of DME and H2 in varying proportions and to clarify the effect on generation performance. Conclusions are as follows: (1) For a supply of DME and H2 mixed gas, DME is consumed after the H2 is consumed. By comparing the experimental values with theoretical values of consumption of pure H2, a mixture of DME and H2, and pure DME, it proved to be possible to roughly predict the experimental values by calculation. (2) The voltage value moved to near the DME voltage after the H2 was consumed, the current density increased after the H2 was consumed. (3) During continuous running the voltage load was observed to fluctuate.

Haraguchi, Tadao; Watanabe, Takashi; Yamashita, Masahiro; Tsutsumi, Yasuyuki; Yamashita, Susumu

27

Attrition resistant catalyst for dimethyl ether synthesis in fluidized-bed reactor  

Microsoft Academic Search

Fluidized-bed reactor is a candidate for dimethyl ether (DME) synthesis from syngas because of its excellent heat removal\\u000a capability. In order to improve the attrition resistance of catalyst, an amount of silica sol as binder was added to the catalyst\\u000a composed of methanol synthesis component CuO\\/ZnO\\/Al2O3 and methanol dehydration component HZSM-5, which was prepared by coprecipitation and shaped by spray

Li-hua Teng

2008-01-01

28

Synthesis of dimethyl ether from methanol over aluminium phosphate and silica–titania catalysts  

Microsoft Academic Search

A series of solid–acid catalysts with different content of components were prepared by co-precipitation (sol–gel) method. These samples comprised silica–titania and modified ?-Al2O3 with phosphorus. To determination of optimum ones, the effects of various contents of phosphorus have been investigated. Dehydration of methanol to dimethyl ether (DME) on solid–acid catalysts was studied in a fixed-bed reactor at a temperature of

F. Yaripour; F. Baghaei; I. Schmidt; J. Perregaard

2005-01-01

29

Thermodynamic Simulation of Direct DME Synthesis via Biomass Gasification  

Microsoft Academic Search

A simulation of direct dimethyl ether (DME) synthesis from syn-gas, produced via biomass gasification and catalytic reforming, has been processed on the assumption of both physical and thermodynamic equilibrium. Simulation showed that reaction temperature, pressure and syn-gas composition are have the most important effect on DME synthesis behavior. In which, low temperature and high pressure would be advantageous for DME

Xiaolan Ge; Yingying Zhu; Shurong Wang; Jinsong Zhou; Zhongyang Luo; Sai Gu

2010-01-01

30

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

31

Simulated consumer exposure to dimethyl ether and propane/butane in hairsprays.  

PubMed

Synopsis The potential human exposures from use of dimethyl ether (DME) and 'liquefied petroleum gas'(LPG) arising from use in hairsprays have been assessed. DME and LPG concentrations were measured in the 'breathing zone' of an experimental manikin and an 'accompanying child' designed to simulate human use of hairsprays in a domestic situation and in the breathing zone of a 'stylist' and 'customer' under salon conditions. Results were expressed as the 10 min time weighted average in the air (TWA10) and as the peak concentration in the breathing zone of the 'user'. Following a 10s use of hairspray containing 50% DME or 26% LPG, TWA10 values for an adult user in a closed room (volume 21 m(3)) were on average 114 ppm and 73 ppm respectively. The child TWA10 values were 89 ppm (DME) and 80 ppm (LPG). Leaving the door open during spraying did not significantly alter these values. The peak concentrations measured in the user breathing zone were 1577 ppm of DME and 671 ppm of LPG. Simulated salon use of a hairspray gave a calculated value of 55 ppm DME and 88 ppm LPG for the stylist over an 8 h working period. PMID:19291059

Hartop, P J; Cook, T L; Adams, M G

1991-08-01

32

Highly sensitive dimethyl ether gas sensor utilizing cataluminescence on nanosized MgO/In2O3  

NASA Astrophysics Data System (ADS)

A gaseous sensor was developed for the determination of dimethyl ether (DME) on the basis of its cataluminescence (CTL) emission on the surface of MgO/In2O3 composite (mass ratio = 1:2). The sensor exhibited high sensitivity and selectivity to DME at a temperature of 245?°C. Under the optimized experimental conditions, the linear range of CTL intensity versus DME concentration was 50-12?000?ppm with a limit of detection of 14?ppm (signal to noise (S/N) = 3). By selecting the appropriate ratio of MgO to In2O3 and the detecting wavelength, the CTL intensities of ether and ethanol could be reduced to 7.3% and 3.9% compared with that of DME. For other compounds, including carbon tetrachloride, formaldehyde, dimethyl sulfate and methyl acetate, etc, no emissions or only very weak ones were detected. The sensor was applied to analyze samples spiked with known concentrations of DME. The concentrations of DME in all samples were well quantified with satisfactory recoveries.

Chu, Yixin; Zhang, Qianchun; Zhang, Wanqin; Zhang, Guoyi; Zhu, Shouli

2014-08-01

33

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

SciTech Connect

Through the mid-1980s, Air Products has brought the liquid phase approach to a number of other synthesis gas reactions where effective heat management is a key issue. In 1989, in response to DOE`s PRDA No. DE-RA22-88PC88805, Air Products proposed a research and development program entitled ``Synthesis of Dimethyl Ether and Alternative Fuels in the Liquid Phase from Coal Derived Syngas.`` The proposal aimed at extending the LPMEOH experience to convert coal-derived synthesis gas to other useful fuels and chemicals. The work proposed included development of a novel one-step synthesis of dimethyl ether (DME) from syngas, and exploration of other liquid phase synthesis of alternative fuel directly from syngas. The one-step DME process, conceived in 1986 at Air Products as a means of increasing syngas conversion to liquid products, envisioned the concept of converting product methanol in situ to DME in a single reactor. The slurry reactor based liquid phase technology is ideally suited for such an application, since the second reaction (methanol to DME) can be accomplished by adding a second catalyst with dehydration activity to the methanol producing reactor. An area of exploration for other alternative fuels directly from syngas was single-step slurry phase synthesis of hydrocarbons via methanol and DME as intermediates. Other possibilities included the direct synthesis of mixed alcohols and mixed ethers in a slurry reactor.

Not Available

1993-02-01

34

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

35

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

SciTech Connect

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

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

2008-08-15

36

Process for producing dimethyl ether form synthesis gas  

DOEpatents

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

Pierantozzi, Ronald (Macungie, PA)

1985-01-01

37

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

38

UV, VUV and soft X-ray photoabsorption of dimethyl ether by dipole (e,e) spectroscopies  

Microsoft Academic Search

Absolute UV and VUV photoabsorption oscillator strengths (cross-sections) for the valence shell discrete and continuum regions of dimethyl ether (CH3OCH3, DME) have been measured from 5 to 32 eV using high resolution (HR) (?0.05 eV f.w.h.m.) dipole (e,e) spectroscopy. A wide-range spectrum, spanning the UV, VUV and soft X-ray regions, from 5 to 200 eV has also been obtained at

Renfei Feng; Glyn Cooper; C. E Brion

2000-01-01

39

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

40

Metal Ion Binding: An Electronic Structure Study of M+(dimethyl ether)(n), M= Cu, Ag and Au, (n= 1 - 4) Complexes  

SciTech Connect

The structures and incremental binding enthalpies of cation-ligand complexes formed from a single coinage metal cation (Cu+, Ag+ and Au+) and as many as four dimethyl ether (DME) ligands are studied with second order perturbation theory (MP2) and coupled cluster theory (CCSD(T)). Basis sets of up to augmented quintuple zeta quality were used in an effort to minimize basis set truncation error. The present results are compared with recent collision-induced dissociation measurements for the Cu+(DME)n complexes, as well as with related complexes in which water either replaces dimethyl ether as the ligand or alkali metal cations replace the coinage metals. Agreement between the theoretical and experimental incremental binding enthalpies (kcal/mol) is good for the two larger copper complexes: DH0(Cu+(DME)3)= 13.9 (theory) vs 13.1? 0.9 kcal/mol (expt.) and DH0(Cu+(DME)4)=11.5 (theory) vs 10.8? 2.3 (expt.). For the two smaller, more tightly bound copper complexes, the level of agreement i s somewhat poorer: DH0(Cu+(DME))= 48.4 (theory) vs 44.3? 2.7 kcal/mol (expt.) and DH0(Cu+(DME)2)= 51.3 (theory) vs 46.1? 1.8 (expt.). In general, DME binds copper, silver and gold 15% - 25% more strongly than water.

Feller, David F.(BATTELLE (PACIFIC NW LAB)) [BATTELLE (PACIFIC NW LAB); Dixon, David A.(BATTELLE (PACIFIC NW LAB)) [BATTELLE (PACIFIC NW LAB)

2002-01-01

41

Selective homogeneous synthesis of dimethyl ether from methanol.  

PubMed

Selected Brønsted acidic ionic liquids were tested as homogeneous catalysts for the dehydration of methanol to dimethyl ether. Ionic liquids incorporating an alkanesulfonic acid as a part of the cation, a complex acidic anion, [A(2)H](-), or both, proved to be good catalysts for this process, providing high conversions and selectivities. Homogeneous catalysis in the liquid state represents a novel approach to dimethyl ether synthesis. PMID:20177636

Atkins, Martin P; Earle, Martyn J; Seddon, Kenneth R; Swad?ba-Kwa?ny, Ma?gorzata; Vanoye, Laurent

2010-03-14

42

Microwave spectra of molecules of astrophysical interest. XVIII. Dimethyl ether  

Microsoft Academic Search

The microwave spectra of dimethyl ether (methoxymethane) is critically reviewed and supplemented through calculations which include the contributions of internal rotation and centrifugal distortion in the molecular Hamiltonian. The primary objective of this review is to provide microwave spectral transitions applicable to molecular radio astronomy for the ground vibrational state rotational spectrum of the most abundant isotopic form of dimethyl

F. J. Lovus; H. Lutz; H. Dreizler

1979-01-01

43

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

44

Liquid properties of dimethyl ether from molecular dynamics simulations using ab initio force fields.  

PubMed

We have used molecular dynamic simulations to study the structural and dynamical properties of liquid dimethyl ether (DME) with a newly constructed ab initio force field in this article. The ab initio potential energy data were calculated at the second order Møller-Plesset (MP2) perturbation theory with Dunning's correlation consistent basis sets (up to aug-cc-pVQZ). We considered 17 configurations of the DME dime for the orientation sampling. The calculated MP2 potential data were used to construct a 3-site united atom force field model. The simulation results are compared with those using the empirical force field of Jorgensen and Ibrahim (Jorgensen and Ibrahim, J Am Chem Soc 1981, 103, 3976) and with available experimental measurements. We obtain quantitative agreements for the atom-wise radial distribution functions, the self-diffusion coefficients, and the shear viscosities over a wide range of experimental conditions. This force field thus provides a suitable starting point to predict liquid properties of DME from first principles intermolecular interactions with no empirical data input a priori. PMID:22278976

Wang, Shi-Bao; Li, Arvin Huang-Te; Chao, Sheng D

2012-04-01

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

ULEV potential of a DI/TCI diesel passenger car engine operated on dimethyl ether  

SciTech Connect

This paper describes a feasibility test program on a 2 liter, 4 cylinder DI/TCI passenger car engine operated on the new alternative fuel Dimethyl Ether (DME) with the aim of demonstrating its potential of meeting ULEV (ultra low emission vehicle) emissions (0.2 g/mi NOx in the FTP 75 test cycle) when installed in a full size passenger car. Special attention is drawn to the fuel injection equipment (FIE) as well as combustion system requirements towards the reduction of NOx and combustion noise while keeping energetic fuel consumption at the level of he baseline DI/TCI diesel engine. FIE and combustion system parameters were optimized on the steady state dynamometer by variation of a number of parameters, such as rate of injection, number of nozzle holes, compression ratio, piston bowl shape and exhaust gas recirculation. The paper presents engine test results achieved with DME under various operating conditions and compares these results to those achieved with the diesel version of the same engine.The FTP 75 cycle results were projected from steady state engine maps using a vehicle simulation program taking into account vehicle data and road resistance data of a given vehicle.The cycle results are also compared to actual chassis dynamometer results achieved with the diesel version of the same engine installed in the same vehicle.the passenger car DI/TCI engine adapted for and operated on DME shows very promising results with respect to meeting ULEV NOx emissions without any soot emissions and without the need for a DENOX catalyst. DME fuel consumption on energy basis can be kept very close to the DI diesel value. An oxidation catalyst will be necessary to meet the stringent CO and HC ULEV emission limits.

Kapus, P.E.; Cartellieri, W.P.

1995-12-31

47

75 FR 4288 - Oxirane, 2-Methyl-, Polymer with Oxirane, Dimethyl Ether; Tolerance Exemption  

Federal Register 2010, 2011, 2012, 2013

...FRL-8805-3] Oxirane, 2-Methyl-, Polymer with Oxirane, Dimethyl Ether; Tolerance...for residues of oxirane, 2-methyl-,polymer with oxirane, dimethyl ether (CAS Reg...for residues of oxirane, 2-methyl-, polymer with oxirane, dimethyl ether (CAS...

2010-01-27

48

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

SciTech Connect

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

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

2003-12-19

49

Overall Spray Characteristics of Dimethyl ether and Biodiesel Fuel under the Ambient Pressure Conditions in a High Pressure Chamber  

NASA Astrophysics Data System (ADS)

The purpose of this paper is to investigate the effect of the ambient pressure on the overall spray characteristics of dimethyl ether (DME) and biodiesel fuel spray in a high-pressure combustion chamber. In order to investigate the spray performance under the various ambient pressure conditions, the high-pressure combustion chamber, which can be controlled by nitrogen gas to obtain the ambient pressure conditions, was applied. To determine the macroscopic structure of the spray, such as the spray development process and the axial/radial distance, frozen images of the spray can be obtained directly using a high-speed camera with a light source according to the elapsed time after energizing begins. At the same time, the results from the DME and biodiesel spray under atmospheric conditions were compared with the results from the spray under various ambient pressure conditions in the chamber. According to the spray characteristics, the axial and maximum radial distances of the biodiesel and DME spray decreased with an increase in the ambient pressure. Also, it was shown that the SMD (Sauter mean diameter) of droplets becomes smaller than that of the spray under the atmosphere condition as the ambient pressure in the high pressure chamber increases.

Kim, Hyung Jun; Park, Su Han; Lee, Chang Sik

50

Selective homogeneous and heterogeneous catalytic conversion of methanol/dimethyl ether to triptane.  

PubMed

The demand for specific fuels and chemical feed-stocks fluctuates, and as a result, logistical mismatches can occur in the supply of their precursor raw materials such as coal, biomass, crude oil, and methane. To overcome these challenges, industry requires a versatile and robust suite of conversion technologies, many of which are mediated by synthesis gas (CO + H(2)) or methanol/dimethyl ether (DME) intermediates. One such transformation, the conversion of methanol/DME to triptane (2,2,3-trimethylbutane) has spurred particular research interest. Practically, triptane is a high-octane, high-value fuel component, but this transformation also raises fundamental questions: how can such a complex molecule be generated from such a simple precursor with high selectivity? In this Account, we present studies of this reaction carried out in two modes: homogeneously with soluble metal halide catalysts and heterogeneously over solid microporous acid catalysts. Despite their very different compositions, reaction conditions, provenance, and historical scientific context, both processes lead to remarkably similar products and mechanistic interpretations. In both cases, hydrocarbon chains grow by successive methylation in a carbocation-based mechanism. The relative rates of competitive processes-chain growth by methylation, chain termination by hydrogen transfer, isomerization, and cracking-systematically depend upon the structure of the various hydrocarbons produced, strongly favoring the formation of the maximally branched C(7) alkane, triptane. The two catalysts also show parallels in their dependence on acid strength. Stronger acids exhibit higher methanol/DME conversion but also tend to favor chain termination, isomerization, and cracking relative to chain growth, decreasing the preference for triptane. Hence, in both modes, there will be an optimal range: if the acid strength is too low, activity will be poor, but if it is too high, selectivity will be poor. A related reaction, the methylative homologation of alkanes, offers the possibility of upgrading low-value refinery byproducts such as isobutane and isopentane to more valuable gasoline components. With the addition of adamantane, a hydride transfer catalyst that promotes activation of alkanes, both systems effectively catalyze the reaction of methanol/DME with lighter alkanes to produce heavier ones. This transformation has the further advantage of providing stoichiometric balance, whereas the stoichiometry for conversion of methanol/DME to alkanes is deficient in hydrogen and requires rejection of excess carbon in the form of carbon-rich arenes, which lowers the overall yield of desired products. Alternatively, other molecules can serve as sacrificial sources of hydrogen atoms: H(2) on heterogeneous catalysts modified by cations that activate it, and H(3)PO(2) or H(3)PO(3) on homogeneous catalysts. We have interpreted most of the features of these potentially useful reactions at a highly detailed level of mechanistic understanding, and we show that this interpretation applies equally to these two widely disparate types of catalysts. Such approaches can play a key role in developing and optimizing the catalysts that are needed to solve our energy problems. PMID:22277056

Hazari, Nilay; Iglesia, Enrique; Labinger, Jay A; Simonetti, Dante A

2012-04-17

51

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

SciTech Connect

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

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

2002-07-01

52

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

NASA Technical Reports Server (NTRS)

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

DeMore, W.; Bayes, K.

1998-01-01

53

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

54

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

NASA Astrophysics Data System (ADS)

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

Niide, Yuzuru; Hayashi, Michiro

2004-02-01

55

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

NASA Astrophysics Data System (ADS)

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

Semelsberger, Troy Allen

56

The developmental toxicity of diethylene glycol dimethyl ether in mice.  

PubMed

Diethylene glycol dimethyl ether (diEGdiME) is structurally related to several compounds which produce reproductive and developmental toxicity, including teratogenicity in laboratory animals. In the present study, diEGdiME (0, 62.5, 125, 250, or 500 mg/kg/day) was administered by gavage in distilled water to timed-pregnant CD-1 mice during major organogenesis [gestational days (gd) 6-15]. Clinical status of treated females was monitored daily during treatment and on gd 17. At sacrifice (gd 17), pregnancy was confirmed by uterine examination for 20-24 dams per group; each live fetus was examined for external, visceral, and skeletal malformations. No maternal deaths, morbidity, or treatment-related clinical signs were observed. Reduced maternal weight gain during treatment at greater than or equal to 250 mg/kg/day was primarily attributed to compromised pregnancy status resulting in reduced gravid uterine weight. Maternal weight gain during gestation corrected for gravid uterine weight, and relative liver weight (% body weight) were not affected. Average fetal body weight/litter was significantly reduced at greater than or equal to 125 mg/kg/day. The percentage of postimplantation loss/litter (5, 8, 7, 12, and 50% for control through high dose) and the percentage of malformed live fetuses/litter (0.4, 0, 2, 24, and 96%) were significantly increased at greater than or equal to 250 mg/kg/day. Developmental defects involved primarily the neural tube, limbs and digits, craniofacial structures, abdominal wall, cardiovascular system, urogenital organs, and both the axial and appendicular skeleton. In summary, oral administration of diEGdiME during major organogenesis did not produce any distinctive signs of maternal toxicity, but did produce selective and profound adverse effects upon fetal growth, viability, and morphological development at greater than or equal to 125 mg/kg/day. PMID:3556817

Price, C J; Kimmel, C A; George, J D; Marr, M C

1987-01-01

57

Composition of reaction intermediates for stoichiometric and fuel-rich dimethyl ether flames: flame-sampling mass spectrometry and modeling studies.  

PubMed

Molecular-beam synchrotron photoionization mass spectrometry and electron-ionization mass spectrometry are used for measurements of species mole fraction profiles for low-pressure premixed dimethyl ether (DME) flames with equivalence ratios ranging from near-stoichiometric conditions (Phi = 0.93) to fuel-rich flames near the limits of flat-flame stability (Phi = 1.86). The results are compared with predictions of a recently modified kinetic model for DME combustion [Zhao et al., Int. J. Chem. Kinet., 2008, 40, 1-18] that has been extensively tested against laminar flame speed measurements, jet-stirred reactor experiments, pyrolysis and oxidation experiments in flow reactors, species measurements for burner-stabilized flames and ignition delay measurements in shock tubes. The present comprehensive measurements of the composition of reaction intermediates over a broad range of equivalence ratios considerably extends the range of the previous experiments used for validation of this model and allows for an accurate determination of contributions of individual reactions to the formation or destruction of any given flame species. The excellent agreement between measurements and predictions found for all major and most intermediate species over the entire range of equivalence ratios provides a uniquely sensitive test of details of the kinetic model. The dependence on equivalence ratio of the characteristic reaction paths in DME flames is examined within the framework of reaction path analyses. PMID:19224033

Wang, Juan; Chaos, Marcos; Yang, Bin; Cool, Terrill A; Dryer, Fred L; Kasper, Tina; Hansen, Nils; Osswald, Patrick; Kohse-Höinghaus, Katharina; Westmoreland, Phillip R

2009-03-01

58

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

PubMed

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

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

2009-01-16

59

Cu-based spinel catalysts CuB 2O 4 (B = Fe, Mn, Cr, Ga, Al, Fe 0.75Mn 0.25) for steam reforming of dimethyl ether  

Microsoft Academic Search

Cu-based spinel-oxides CuB2O4 (B=Fe, Mn, Cr, Ga, Al, or Fe0.75Mn0.25) were synthesized via a sol–gel method and subsequent solid-state reaction. The spinels mechanically mixed with ?-Al2O3 were evaluated for production of hydrogen from dimethyl ether steam reforming (DME SR). The reduction behavior and crystal property of these spinel-oxides, and the Cu oxidation state in spinel catalysts were investigated by temperature-programmed

Kajornsak Faungnawakij; Naohiro Shimoda; Tetsuya Fukunaga; Ryuji Kikuchi; Koichi Eguchi

2008-01-01

60

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

61

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

NASA Astrophysics Data System (ADS)

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

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

2006-01-01

62

DME-Fired Water-Tube Boiler─A R&D Study  

NASA Astrophysics Data System (ADS)

Increasing attention has been given to the development of low-NOx combustion technology for DME (Dimethyl Ether). The present paper describes the R&D study for water-tube boiler carried out in Kansai University and Hirakawa Guidam Co., Ltd. under the support of DME project from METI. The major problem in DME use is the difficulty in the application of premixed flame due to its low ignition temperature and rather high burning velocity. However, the previously developed tube-nested combustor, i.e. water-tubes installed in the empty furnace, becomes effective means together with the flue-gas recirculation to overcome such difficulty in achieving low-NOx combustion. This paper begins with a brief review of the R&D study of the tube-nested combustor specifically designed for city gas. Then the further development for DME-fired water-tube boiler is described.

Ozawa, Mamoru; Matsumoto, Ryosuke; Higuchi, Nobuo; Hayashi, Yoshio; Uematsu, Hiroki; Suita, Yoshitaka

63

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

SciTech Connect

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

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

2003-06-01

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

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

NASA Astrophysics Data System (ADS)

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

Niide, Yuzuru; Hayashi, Michiro

2003-07-01

67

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

SciTech Connect

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

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

1998-09-01

68

Development of Low-NOx DME Multi-Port Burner  

NASA Astrophysics Data System (ADS)

This study focuses on the fundamental characteristics of DME (Dimethyl Ether) combustion, aiming at the development of low-NOx multi-port burner suitable for the tube-nested combustor. In the tube-nested combustion, the water tubes are moved into the furnace closely to the burner to cool the burning flame directly in the field of burning reaction leading to NOx reduction. To prevent the unburned combustibles emission, the diffusion burner used in the tube-nested combustor needs a high performance of the fuel-air mixing. Multi-port burner consists of a fuel-port and surrounding multi-air-ports, which induce a strong re-circulation flow. Thus the fuel-air mixing is enhanced so that the thermal NOx and CO emissions are significantly reduced. The NOx emission of the DME from the co-axial diffusion burner was over 130ppm at 0% O2. On the other hand, NOx emission of DME from the multi-port burner was reduced to 60ppm at 0% O2. With the help of the tube-nested combustion, NOx emission of DME was further reduced to 20ppm at 0% O2.

Matsumoto, Ryosuke; Ozawa, Mamoru; Ishihara, Isao; Sasaki, Shingo; Takaichi, Masahiro

69

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

70

Dynamic Mechanical Properties of Poly(2,6-Dimethyl-1,4-Phenylene Ether)-Polystyrene Blends.  

National Technical Information Service (NTIS)

Blends of poly(2,6-dimethyl-1,4-phenylene ether) (PPO) and atactic polystyrene (PS) have been prepared by mechanically mixing powders of the two polymers and subjecting the mixtures to three different thermal treatments. Three different compositions were ...

J. Stoelting, F. E. Karasz, W. J. MacKnight

1970-01-01

71

Short and stereoselective total synthesis of furano lignans (+/-)-dihydrosesamin, (+/-)-lariciresinol dimethyl ether, (+/-)-acuminatin methyl ether, (+/-)-sanshodiol methyl ether, (+/-)-lariciresinol, (+/-)-acuminatin, and (+/-)-lariciresinol monomethyl ether and furofuran lignans (+/-)-sesamin, (+/-)-eudesmin, (+/-)-piperitol methyl ether, (+/-)-pinoresinol, (+/-)-piperitol, and (+/-)-pinoresinol monomethyl ether by radical cyclization of epoxides using a transition-metal radical source.  

PubMed

Intramolecular radical cyclization of suitably substituted epoxy ethers 4a-g using bis(cyclopentadienyl)titanium(III) chloride as the radical source resulted in trisubstituted tetrahydrofurano lignans and 2,6-diaryl-3,7-dioxabicyclo[3.3.0]octane lignans depending on the reaction conditions. The titanium(III) species was prepared in situ from commercially available titanocene dichloride and activated zinc dust in THF. Upon radical cyclization followed by acidic workup, epoxy olefinic ethers 4a-g afforded furano lignans dihydrosesamin 1a, lariciresinol dimethyl ether 1b, acuminatin methyl ether 1e, and sanshodiol methyl ether 1g directly and lariciresinol 1h, acuminatin 1i, and lariciresinol monomethyl ether 1j after removal of the benzyl protecting group by controlled hydrogenolysis of the corresponding cyclized products. The furofuran lignans sesamin 2a, eudesmin 2b, and piperitol methyl ether 2e were also prepared directly by using the same precursors 4a-f on radical cyclization followed by treatment with iodine and pinoresinol 2h, piperitol 2i, and pinoresinol monomethyl ether 2j after controlled hydrogenolysis of the benzyl protecting group of the corresponding cyclized products. Two naturally occurring acyclic lignans, secoisolariciresinol 5h and secoisolariciresinol dimethyl ether 5b, have also been prepared by exhaustive hydrogenolysis of 2h and 2b, respectively. PMID:12003531

Roy, Subhas Chandra; Rana, Kalyan Kumar; Guin, Chandrani

2002-05-17

72

The developmental toxicity of diethylene and triethylene glycol dimethyl ethers in rabbits.  

PubMed

Diethylene glycol dimethyl ether (diEGdiME) and triethylene glycol dimethyl ether (triEGdiME), widely used organic solvents, are structurally related to several compounds that produce reproductive and developmental toxicity, including teratogenicity in laboratory animals. In the present studies, diEGdiME (0, 25, 50, 100, or 175 mg/kg/day) or triEGdiME (0, 75, 125, 175, or 250 mg/kg/day) were administered by gavage in distilled water to timed-pregnant New Zealand white rabbits (15-25 dams/group) during major organogenesis [Gestational Days (gd) 6-19]. Treated females were euthanized on gd 30, uterine contents were examined, and live fetuses were examined for morphological alterations. In the diEGdiMe study, evidence of maternal toxicity, per se, was observed only at 175 mg/kg/day with 15% mortality among treated females compared to 4% among controls. No significant maternal toxicity was observed in the 25 mg/kg/day group, and only minimal maternal toxicity (decreased maternal weight gain during treatment) was observed at 50 and 100 mg/kg/day compared to the vehicle control group. The no-observed-adverse-effect level for developmental toxicity in rabbits for diEGdiME was 50 mg/kg/day. The incidences of prenatal mortality and malformed live fetuses were significantly above controls at 100 and 175 mg/kg/day. Malformations observed most frequently included fusion of ribs to each other and hydronephrosis; clubbing of the limbs without underlying bone deformities, a variation, was also observed. In the triEGdiME study, clinical signs of toxicity were minimal and there was no increased maternal mortality. Maternal body weight and gravid uterine weight were significantly reduced at 250 mg/kg/day, whereas maternal weight gain during treatment was significantly depressed at doses of 175 mg/kg/day and above.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1516781

Schwetz, B A; Price, C J; George, J D; Kimmel, C A; Morrissey, R E; Marr, M C

1992-08-01

73

Multiphase fluidization in large-scale slurry jet loop bubble columns for methanol and or dimethyl ether production  

Microsoft Academic Search

A solution methodology is proposed for the process development and process engineering of a continuously operated jet loop bubble column including integrated external or internal steam generation for, e.g., a high-efficiency large-scale medium pressure methanol and or dimethyl ether production, or other gas to liquid Fischer–Tropsch applications.A jet loop bubble column is defined in the present process development to study

A. Bakopoulos

2006-01-01

74

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

75

Matrix infrared spectroscopic and theoretical studies on the reactions of scandium, yttrium, and lanthanide metal atoms with dimethyl ether.  

PubMed

Reactions of laser-ablated scandium, yttrium, lanthanum, and several lanthanide metal atoms with dimethyl ether have been studied using matrix isolation infrared spectroscopy. Identifications of the major products, M(CH(3)OCH(3)) and CH(3)OMCH(3) (M = Sc, Y, La, Ce, Gd, Tb, Yb, and Lu), are supported by experiments with deuterium substitution as well as theoretical calculations. It is found that most ground-state metal atoms react with dimethyl ether to give the M(CH(3)OCH(3)) complexes spontaneously on annealing, which isomerize to the CH(3)OMCH(3) insertion products with visible irradiation. Density functional calculations reveal that the M(CH(3)OCH(3)) complexes possess C(2v) symmetry with metal atoms bound to the oxygen side of dimethyl ether, and bent geometries are found for the inserted CH(3)OMCH(3) molecules with direct M-O and C-O bonds. All of these products have the same ground states as their corresponding metal atoms except for Tb. Although the Lu(CH(3)OCH(3)) complex is predicted to be a stable molecule, it is not observed in the experiment due to the low energy barrier for the subsequent C-O bond insertion reaction. PMID:21870806

Gong, Yu; Andrews, Lester

2011-10-27

76

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

PubMed Central

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

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

2013-01-01

77

Virial equation of state and ideal-gas heat capacities of pentafluoro-dimethyl ether  

SciTech Connect

A virial equation of state is presented for vapor-phase pentafluoro-dimethyl ether (CF{sub 3}-O-CF{sub 2}H), a candidate alternative refrigerant known as E125. The equation of state was determined from density measurements performed with a Burnett apparatus and from speed-of-sound measurements performed with an acoustical resonator. The speed-of-sound measurements spanned the ranges 260 {le} T {le} 400 K and 0.05 {le} P {le} 1.0 MPa. The Burnett measurements covered the ranges 283 {le} T {le} 373 K and 0.25 {le} P {le} 5.0 MPa. The speed-of-sound and Burnett measurements were first analyzed separately to produce two independent virial equations of state. The equation of state from the acoustical measurements reproduced the experimental sound speeds with a fractional RMS deviation of 0.0013%. The equation of state from the Burnett measurements reproduced the experimental pressures with a fractional RMS deviation of 0.012%. Finally, an equation of state was fit to both the speed-of-sound and the Burnett measurements simultaneously. The resulting equation of state reproduced the measured sound speeds with a fractional RMS deviation of 0.0018% and the measured Burnett densities with a fractional RMS deviation of 0.019%.

Hurly, J.J.; Schmidt, J.W.; Gillis, K.A. [National Inst. of Standards and Technology, Gaithersburg, MD (United States)

1997-01-01

78

A Life Cycle Analysis on a Bio-DME production system considering the species of biomass feedstock in Japan and Papua New Guinea  

Microsoft Academic Search

This paper describes the performance and\\/or CO2 intensities of a Bio-DME (Biomass Di-methyl Ether) production system, considering the differences of biomass feedstock. In the past LCA studies on an energy chain model, there is little knowledge on the differences of biomass feedstock and\\/or available condition. Thus, in this paper, we selected Papua New Guinea (PNG) which has good potential for

Masashi Higo; Kiyoshi Dowaki

2010-01-01

79

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

E-print Network

as a convenient energy carrier for distributed power generation, space heating, and diesel replace- ment by combining isotopic and kinetic analyses with density functional theory estimates of reaction energies steady- state vacancy concentrations and a consequently smaller number of adsorbed DME intermediates

Iglesia, Enrique

80

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

81

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

82

Combining activated carbon adsorption with heterogeneous photocatalytic oxidation: lack of synergy for biologically treated greywater and tetraethylene glycol dimethyl ether.  

PubMed

The aim of the study was to evaluate whether the addition of activated carbon in the photocatalytic oxidation of biologically pretreated greywater and of a polar aliphatic compound gives synergy, as previously demonstrated with phenol. Photocatalytic oxidation kinetics were recorded with fivefold concentrated biologically pretreated greywater and with aqueous tetraethylene glycol dimethyl ether solutions using a UV lamp and the photocatalyst TiO2 P25 in the presence and the absence of powdered activated carbon. The synergy factor, SF, was quantified as the ratio of photocatalytic oxidation rate constant in the presence of powdered activated carbon to the rate constant without activated carbon. No synergy was observed for the greywater concentrate (SF approximately 1). For the aliphatic compound, tetraethylene glycol dimethyl ether, addition of activated carbon actually had an inhibiting effect on photocatalysis (SF < 1), while synergy was confirmed in reference experiments using aqueous phenol solutions. The absence of synergy for the greywater concentrate can be explained by low adsorbability of its organic constituents by activated carbon. Inhibition of the photocatalytic oxidation of tetraethylene glycol dimethyl ether by addition of powdered activated carbon was attributed to shading of the photocatalyst by the activated carbon particles. It was assumed that synergy in the hybrid process was limited to aromatic organics. Regardless of the lack of synergy in the case of biologically pretreated greywater, the addition of powdered activated carbon is advantageous since, due to additional adsorptive removal of organics, photocatalytic oxidation resulted in a 60% lower organic concentration when activated carbon was present after the same UV irradiation time. PMID:24191472

Gulyas, Holger; Argáez, Angel Santiago Oria; Kong, Fanzhuo; Jorge, Carlos Liriano; Eggers, Susanne; Otterpohl, Ralf

2013-01-01

83

Combining activated carbon adsorption with heterogeneous photocatalytic oxidation: Lack of synergy for biologically treated greywater and tetraethylene glycol dimethyl ether  

PubMed Central

The aim of the study was to evaluate whether the addition of activated carbon in the photocatalytic oxidation of biologically pretreated greywater and of a polar aliphatic compound gives synergy, as previously demonstrated with phenol. Photocatalytic oxidation kinetics were recorded with fivefold concentrated biologically pretreated greywater and with aqueous tetraethylene glycol dimethyl ether solutions using a UV lamp and the photocatalyst TiO2 P25 in the presence and the absence of powdered activated carbon. The synergy factor, SF, was quantified as the ratio of photocatalytic oxidation rate constant in the presence of powdered activated carbon to the rate constant without activated carbon. No synergy was observed for the greywater concentrate (SF ? 1). For the aliphatic compound, tetraethylene glycol dimethyl ether, addition of activated carbon actually had an inhibiting effect on photocatalysis (SF < 1), while synergy was confirmed in reference experiments using aqueous phenol solutions. The absence of synergy for the greywater concentrate can be explained by low adsorbability of its organic constituents by activated carbon. Inhibition of the photocatalytic oxidation of tetraethylene glycol dimethyl ether by addition of powdered activated carbon was attributed to shading of the photocatalyst by the activated carbon particles. It was assumed that synergy in the hybrid process was limited to aromatic organics. Regardless of the lack of synergy in the case of biologically pretreated greywater, the addition of powdered activated carbon is advantageous since, due to additional adsorptive removal of organics, photocatalytic oxidation resulted in a 60% lower organic concentration when activated carbon was present after the same UV irradiation time. PMID:24191472

Gulyas, Holger; Argáez, Ángel Santiago Oria; Kong, Fanzhuo; Jorge, Carlos Liriano; Eggers, Susanne; Otterpohl, Ralf

2013-01-01

84

Performance Analysis of heat pump cycle using CO2/DME refrigerant mixture  

NASA Astrophysics Data System (ADS)

Performance analyses have been carried out for a heat pump cycle using zeotropic refrigerant mixtures of carbon dioxide (CO2) and dimethyl ether (DME). In order to clarify the characteristics and coefficient of performance (COP) of CO2/DME heat pump cycle, the concentration of mixture was varied over a wide range. The calculation conditions were established as a hot-water supply system and the calculations were conducted by considering the heat transfer between the refrigerant and heat source/sink water. Because the heat transfer between refrigerant and heat source/sink water strongly affects on the cycle behavior, effects of the heat transfer capability parameter were investigated. The heat pump cycle is formed around the critical point for high CO2 concentration mixtures and it is formed under the critical point for low CO2 concentration mixtures. The COP has the maximum at a certain pressure for each mixture and the COPs of the mixture and pure DME are higher than that of pure CO2. Operating pressure decreases with increase of DME concentration. The effects of heat transfer between the refrigerant and heat source/sink water on characteristics of the cycle have also been clarified.

Onaka, Yoji; Miyara, Akio; Tsubaki, Koutaro; Koyama, Shigeru

85

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

86

Low NOx Combustion of DME by Means of Flue Gas Recirculation  

NASA Astrophysics Data System (ADS)

This study focuses on the fundamental characteristics of DME (Dimethyl Ether) combustion aiming at development of low-NOx combustion technology with flue gas recirculation, FGR. The flue gas is recirculated into the combustion chamber to reduce the oxygen concentration and to suppress the combustion gas temperature, so that NOx emission is significantly reduced. The fuel gas recirculation at high mixing ratio, however, may lead to unstable combustion of conventional fuels, methane or city gas. On the other hand, DME has very high potential of applicability for the flue gas recirculation even at high mixing ratio because of its high burning velocity and low ignition temperature. Combustion tests were conducted with laboratory-scale 11kW combustor. The maximum FGR ratio is 85% at the initial air ratio of 1.5 with preheated diluted air about 600K. The NOx emission reduced to 13ppm at 0%-O2, which corresponds to about 9% of NOx emission at FGR=0%. The stable combustion is sustained even in the low oxygen concentration by preheating diluted-air up to near the auto-ignition temperature of DME. Finally, the effect of the flue gas recirculation on the NOx and CO emission is discussed with reference to the industrial-scale water-tube boilers.

Matsumoto, Ryosuke; Ozawa, Mamoru; Terada, Shinya; Iio, Takenori

87

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

SciTech Connect

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

Underwood, R.P.

1993-01-01

88

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

SciTech Connect

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

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

2011-09-20

89

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

90

Calculations for the Properties and Reactions of the NH, PH, and AsH Counterparts of Dimethyl Ether and Acetone.  

PubMed

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

Wiberg, Kenneth B

2014-11-21

91

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

SciTech Connect

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

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

2011-12-31

92

Spasmolytic effect of galetin 3,6-dimethyl ether, a flavonoid obtained from Piptadenia stipulacea (Benth) Ducke.  

PubMed

Piptadenia stipulacea (Benth) Ducke is a tree of the Caatinga, in Northeast Brazil, popularly known as "Jurema-branca", "Jurema malícia-da-serra", "Carcará" and "Calumbi". In folk medicine, a decoction or tincture of its bark and leaves are used to treat wounds and as healing agents. Galetin 3,6-dimethyl ether (FGAL) is a flavonoid isolated from the aerial components of Piptadenia stipulacea (Benth) Ducke. We decided to investigate a possible FGAL spasmolytic effect on preparations of both the guinea pig ileum and trachea, the rat uterus and the male rat aorta. FGAL inhibited oxytocin (IC(50) = 2.2 ± 0.4 × 10(-5) M) and carbachol (CCh)-induced (IC(50) = 7.7 ± 1.3 × 10(-5) M) phasic contractions in the rat uterus, but was more effective in the inhibition of the oxytocin-induced contractions. In the guinea pig ileum, FGAL equipotently inhibited CCh (IC(50) = 2.8 ± 0.4 × 10(-5) M) and histamine-induced (IC(50) = 2.3 ± 0.5 × 10(-5) M) phasic contractions. FGAL equipotently and concentration-dependently relaxed guinea pig trachea preparations pre-contracted with CCh, both in the absence (EC(50) = 0.8 ± 0.1 × 10(-5) M) and presence (EC(50) = 1.0 ± 0.1 × 10(-5) M) of a functional epithelium. FGAL also relaxed preparations of the rat aorta pre-contracted with phenylephrine in both the absence (EC(50) = 5.0 ± 1.1 × 10(-6) M) and presence (EC(50) = 5.4 ± 1.2 × 10(-6) M) of a functional endothelium. FGAL shows a non-selective spasmolytic effect on each of the smooth muscle preparations we have tested, but with a greater effect on those from the rat aorta. The relaxant effect on preparations of both the guinea pig trachea and the rat aorta seems to not involve the epithelium or endothelium-derived relaxing factors. PMID:22104374

Macêdo, Cibério Landim; Vasconcelos, Luiz Henrique César; Correia, Ana Carolina de C; Martins, Italo Rossi Roseno; de Lira, Daysianne Pereira; Santos, Bárbara Viviana de Oliveira; da Silva, Bagnólia Araújo

2011-01-01

93

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. PMID:24957059

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

2013-01-01

94

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

95

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

96

Reproductive toxicity of the glycol ethers.  

PubMed

The glycol ethers are an important and widely used class of solvents. Recent studies have demonstrated that ethylene glycol monomethyl ether (EGME), ethylene glycol dimethyl ether (EGdiME), ethylene glycol monoethyl ether (EGEE), and ethylene glycol monoethyl ether acetate (EGEEA) are teratogenic. Other studies have demonstrated that testicular atrophy or infertility follow treatment of males with EGME, ethylene glycol monomethyl ether acetate (EGMEA), EGEE, EGEEA, diethylene glycol dimethyl ether (diEGdiME), and diethylene glycol monoethyl ether (diEGEE). Experimental data are reviewed and structure-activity relationships are speculated upon. PMID:6351353

Hardin, B D

1983-06-01

97

Nature of K[sup +]/crown ether interactions. A hybrid quantum mechanical-molecular mechanical study  

SciTech Connect

We present a hybrid quantum mechanical/molecular mechanical (QM/MM) molecular dynamics study of dimethyl ether (DME) and 18-crown-6 (18c6) interacting with K[sup +]. The QM/MM method employs the semiempirical AM1 method to describe the ethers, the MM parametrization of Dang for K[sup +], and the MM SPC/e model for H[sub 2]O. We parametrize the interaction Hamiltonian to the binding energies and optimized geometries for K[sup +]/DME using ab initio HF and MP2/6-31+G* results. The resulting QM/MM model describes the polarization response of both free DME and K[sup +]-complexed DME well. The QM/MM model gives good agreement with the experimental and ab initio structures for K[sup +]/18c6. We calculate gas-phase K[sup +]/18c6 binding energies of [minus]70.2 and [minus]72.0 kcal/mol with the QM/MM and MP2/6-31+G* (CP corrected) methods, respectively. Our simulation results for K[sup +]/18c6 in H[sub 2]O show that the most probable K[sup +]/18c6 center-of-mass displacement is 0.25 [angstrom], in marked contrast to previous molecular dynamics results of Dang and Kollman. Our result is consistent with K[sup +] having an optimal [open quotes]fit[close quotes] for the cavity of 18c6. Still, we find that K[sup +] retains significant solvent accessibility coordinating two H[sub 2]O molecules, on average, in the K[sup +]/18c6 simulation. 81 refs., 13 figs., 4 tabs.

Thompson, M.A.; Glendening, E.D.; Feller, D. (Pacific Northwest Lab., Richland, WA (United States))

1994-10-13

98

Comparative analysis of the H-F stretching band in absorption spectra of gas-phase complexes of HF with water, dimethyl ether, and acetone  

NASA Astrophysics Data System (ADS)

Comparative analysis of the ?1(H-F) stretching band shapes in the absorption spectra of complexes of HF with water, dimethyl ether, and acetone and the mechanisms of formation of this band is performed by comparing the experimental spectra and results of nonempirical quantum-mechanical calculations. The experimental spectra of complexes considered were obtained by subtracting the spectra of monomers from the experimental spectra of gaseous mixtures recorded at different temperatures in the region of the ?1(H-F) band at a high resolution with Bruker IFS-113v and ?ruker IFS-125 HR vacuum Fourier spectrometers. These spectra are compared with the band shapes reconstructed theoretically with the use of electro-optical parameters obtained from variational solutions of multidimensional anharmonic vibrational problems. The equilibrium geometries of the complexes, their potential energy and dipole moment surfaces necessary for solving these problems were calculated ab initio at a high level of theory. In this approach the internal anharmonicity of the ?1(H-F) mode and its interaction with all low-frequency intermolecular modes are considered explicitly. Anharmonic interactions between different intermolecular motions are also analyzed in detail. The inter-mode interactions are found to have different effects on the frequency and absolute intensity of the ?1(H-F) fundamental transition. Comparison of the data for different complexes shows that the resulting spectral manifestations of the anharmonic effects depend on the interplay between the H-bond strength, the barrier height for tunneling, the magnitudes of frequencies of intermolecular vibrations, rotational constants, etc. The reconstruction of spectra as a superposition of rovibrational bands of the fundamental, hot, and combination transitions with calculated values of absolute intensities can reproduce the shape and separate details of the experimental spectra. Analysis of the experimental and calculated data provides reliable values of the fundamental ?1(H-F) transition frequency, indicates its position in the spectrum, and elucidates the nature of different structural features.

Bulychev, V. P.; Tokhadze, K. G.

2010-07-01

99

Stabilized three-stage oxidation of DME/air mixture in a micro flow reactor with a controlled temperature profile  

SciTech Connect

Ignition and combustion characteristics of a stoichiometric dimethyl ether (DME)/air mixture in a micro flow reactor with a controlled temperature profile which was smoothly ramped from room temperature to ignition temperature were investigated. Special attention was paid to the multi-stage oxidation in low temperature condition. Normal stable flames in a mixture flow in the high velocity region, and non-stationary pulsating flames and/or repetitive extinction and ignition (FREI) in the medium velocity region were experimentally confirmed as expected from our previous study on a methane/air mixture. In addition, stable double weak flames were observed in the low velocity region for the present DME/air mixture case. It is the first observation of stable double flames by the present methodology. Gas sampling was conducted to obtain major species distributions in the flow reactor. The results indicated that existence of low-temperature oxidation was conjectured by the production of CH{sub 2}O occured in the upstream side of the experimental first luminous flame, while no chemiluminescence from it was seen. One-dimensional computation with detailed chemistry and transport was conducted. At low mixture velocities, three-stage oxidation was confirmed from profiles of the heat release rate and major chemical species, which was broadly in agreement with the experimental results. Since the present micro flow reactor with a controlled temperature profile successfully presented the multi-stage oxidations as spatially separated flames, it is shown that this flow reactor can be utilized as a methodology to separate sets of reactions, even for other practical fuels, at different temperature. (author)

Oshibe, Hiroshi; Nakamura, Hisashi; Tezuka, Takuya; Hasegawa, Susumu; Maruta, Kaoru [Institute of Fluid Science, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577 (Japan)

2010-08-15

100

Oxidation of dimethyl-ether and ethylene in the atmosphere and combustion environment and thermodynamic studies on hydrofluorocarbons usingab initio calculation methods  

NASA Astrophysics Data System (ADS)

Reaction pathways and kinetics are analyzed on CH3OC.H2 unimolecular decay and on the complete CH3OC.H2 + O2 reaction system using thermodynamic properties DHdegf 298,Sdeg 298, and Cp(T) 300 <= T/K <= 1500) derived by two ab initio calculation methods, CBS-q and G2. These are used to determine thermodynamic properties of reactants, intermediate radicals and transition state (TS) compounds. Quantum Rice-Ramsperger-Kassel (QRRK) analysis is used to calculate energy dependent rate constants, k(E), and master equation is used to account for collisional stabilization. Comparison of calculated fall-off with experiment indicates that the CBS-q and G2 calculated Ea,rxn for the rate controlling transition state (?-scission reaction to CH 2O + C.H2OOH) needs to be lowered by factor of 3.3 kcal/mol and 4.0 kcal/mol respectively in order to match the data of Sehested et al. Experimental results on dimethyl-ether pyrolysis and oxidation reaction systems are compared with a detailed reaction mechanism model. The computer code CHEMKIN II is used for numerical integration. Overall agreement of the model data with experimental data is very good. Reaction pathways are analyzed and kinetics are determined on formation and reactions of the adduct resulting from OH addition to ethylene using the above ab initio methods. Hydrogen atom tunneling is included by use of Eckart formalism. Rate constants are compared with experimentally determined product branching ratios (C.H2CH 2OH stabilization: CH2O + CH3: CH3CHO + H). ab initio calculations are performed to estimate thermodynamic properties of nine fluorinated ethane compounds (fluoroethane to hexafluoroethane), eight fluoropropane (1-fluoropropane, 1,1- and 1,2- difluoropropane, 1,1,1- and 1,1,2-trifluoropropane, 1,1,1,2- and 1,1,2,2-tetrafluoropropane and 1,1,1,2,2- pentafluoropropane), and 2-fluoro,2-methylpropane. Standard entropies and heat capacities are calculated using the rigid-rotor-harmonic-oscillator approximation with direct integration over energy levels of the intramolecular rotation potential energy curve. Enthalpies of formation are estimated using G2MP2 total energies and isodesmic reactions. Thermodynamic properties for fluorinated carbon groups C/C/F/H2, C/C/F2/H, C/C/F3, C/C2/F/H, C/C2/F2 and C/C3/F for fluorinated alkane compounds, CD/F/H and CD/F2 for fluorinated alkene compounds and CT/F for fluorinated alkyne compounds are estimated. Fluorine-fluorine interaction terms F/F, 2F/F, 3F/F, 2F/2F, 3F/2F and 3F/3F for alkane compounds, F//F, 2F//F and 2F/2F for alkene compounds, and F///F for alkyne compound are also estimated.

Yamada, Takahiro

1999-08-01

101

Effects of methylated, organic, and inorganic substrates on microbial consumption of dimethyl sulfide in estuarine waters.  

PubMed

We examined the effects of a variety of amendments on the consumption of [U-C]dimethyl sulfide in a Georgia salt marsh. Methylated compounds, particularly those with dimethyl groups, significantly inhibited dimethyl sulfide consumption, while nonmethylated substrates had little effect. Dimethyl disulfide and dimethyl ether were the most effective inhibitors tested. PMID:16349026

Wolfe, G V; Kiene, R P

1993-08-01

102

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  

SciTech Connect

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

Underwood, R.P.

1993-01-01

103

Direct synthesis of dimethyl ether as a green fuel from syngas over nanostructured CuO-ZnO-Al2O3/HZSM-5 catalyst: Influence of irradiation time on nanocatalyst properties and catalytic performance  

NASA Astrophysics Data System (ADS)

CuO-ZnO-Al2O3/HZSM-5 (CZAZ) nanocatalyst is prepared by ultrasound-assisted co-precipitation method at different irradiation times, characterized and tested for direct synthesis of DME from syngas. Synthesized nanocatalysts were characterized using XRD, FESEM, PDS, EDX and BET techniques. Direct synthesis of DME is carried out at 200-300 °C and 10-40 bar using a mixture of CO:H2 = 2:1. The catalyst with the longest sonication time showed the smallest degree of aggregates, the highest dispersion and surface area. Although the long irradiated nanocatalyst has slightly bigger CuO crystal size but the size of particle aggregates was small and less populated. The sonicated catalyst with longest irradiation presented a high CO conversion of ca. 40%. It seems that, not the CuO crystal size but the size of particle aggregates and nanocatalyst surface had a great effect on the CZAZ nanocatalyst performance. While there was an optimal temperature for CO conversion and DME yield in direct synthesis of DME, both the CO conversion and the DME yield increased with the pressure increase. Long irradiated nanocatalyst yielded more stable CuO-ZnO-Al2O3/HZSM-5 nanocatalyst while conventional co-precipitated nanocatalyst lost its activity ca. 11% and 58% in terms of CO conversion and DME yield, respectively, in 24 h time on stream test.

Allahyari, Somaiyeh; Haghighi, Mohammad; Ebadi, Amanollah; Qavam Saeedi, Habib

2014-12-01

104

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

NASA Astrophysics Data System (ADS)

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

Seidel, C.; Schäfer, A. H.; Fuchs, H.

2000-07-01

105

Dimethyl Fumarate  

MedlinePLUS

... muscle coordination, and problems with vision, speech, and bladder control). Dimethyl fumarate is in a class of ... your regular dosing schedule. Do not take a double dose to make up for a missed one.

106

Spin-Peierls transition of the quasi-one-dimensional electronic system (DMe-DCNQI)2M (M=Li,Ag) probed by heat capacity  

NASA Astrophysics Data System (ADS)

Through ac and thermal relaxation calorimetry techniques, we have performed a thermodynamic investigation of the spin-Peierls systems, (DMe-DCNQI)2Ag and (DMe-DCNQI)2Li, where DMe-DCNQI is 2,5-dimethyl-N,N'-dicyanoquinonediimine. The fully gapped nature characteristic of the spin-Peierls (sP) ground state was confirmed by the absence of ? (T-linear) term in the low-temperature heat capacity for a single crystal. At higher temperatures, two distinct peaks were observed at 71 K and 86 K in heat capacity of (DMe-DCNQI)2Ag, while only a single peak was observed at 52 K for (DMe-DCNQI)2Li. The two-step structure in the Ag salt suggests that the sP transition of this material involves an intermediate state which is probably attributable to the degrees of freedom inside the dimers. For compacted pellets of numerous pieces of tiny crystals, however, the thermal anomaly around the sP transition disappears, but instead a ? term probably associated with the one-dimensional antiferromagnetic spin excitations appears. This implies that the present sP state is quite fragile against disorder or stress. These findings can be regarded as novel features of the sP transition in the quarter-filled band systems.

Nakazawa, Yasuhiro; Sato, Akane; Seki, Mitsuro; Saito, Kazuya; Hiraki, Ko-Ichi; Takahashi, Toshihiro; Kanoda, Kazushi; Sorai, Michio

2003-08-01

107

VLA observation of dMe stars  

NASA Astrophysics Data System (ADS)

We present new VLA radio observations of a sample of dMe stars in X, U, K, and Q bands (from 8.4 to 43 GHz) obtained during an observing campaign in 1996 April-June. The aim of the project was to determine the spectral energy distributions of late-type dwarf flare stars to investigate the possible existence of an inversion of the spectrum slope at frequencies higher than 8 GHz. We also tried to constrain the possible emission mechanism at radio frequencies. We have detections in X band (8.4 GHz), for three sources (UV Cet, V 1054 Oph, and EV Lac), while all of our other measurements are upper limits. We discuss how the weak radio emission of some sources (e.g. AU Mic) and the coronal plasma properties deduced from X-ray observations constrain the coronal magnetic field properties.

Leto, G.; Pagano, I.; Linsky, J. L.; Rodonò, M.; Umana, G.

2000-07-01

108

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

109

Consequences of the formation of 3,4-dimethyl-5-phenyl-1,3-oxazolidine on the analysis of ephedrines in urine by gas chromatography and a new method for confirmation as N-trifluoroacetyl-O-t-butyldimethylsilyl ether derivatives  

Microsoft Academic Search

The compound 3,4-dimethyl-5-phenyl-1,3-oxazolidine can appear as an artifact during the gas chromatographic analysis of ephedrines. Its presence is a risk for doping control and forensic analyses. An evaluation about the consequences of its formation showed the possibility of a false positive for ephedrine, a false negative for pseudophedrine and increased uncertainty in the quantitative approach. Misinterpretations can be avoided with

V. F. Sardela; P. D. O. Sardela; H. M. G. Pereira; F. R. Aquino Neto

2011-01-01

110

Experimental studies on toxicity of ethylene glycol alkyl ethers in Japan.  

PubMed Central

Past studies on the toxicological effects of ethylene glycol alkyl ethers as well as the recent data on these chemicals in Japan are reviewed. Only a few researchers have participated in the study of ethylene glycol alkyl ethers in Japan. The effects of ethylene glycol alkyl ethers on testis and embryotoxic effects of ethylene glycol monomethyl ether (EGM) have been studied, as has the teratogenicity of ethylene glycol dimethyl ether (EGdM). Studies on ethylene glycol alkyl ethers and related compounds administered to mice by oral gavage revealed the occurrence of testicular atrophy and decreased white blood cell count by EGM, EGdM, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether and ethylene glycol monoethyl ether acetate, and the toxicity was related to their chemical structure. On the other hand, ethylene glycol, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monophenyl ether, ethylene glycol monoacetate or ethylene glycol diacetate showed no such an effect. Studies on EGM using hamsters or guinea pigs revealed the occurrence of testicular atrophy similar to that observed in mice. In regard to the methyl ethers of other glycols, there is no convincing evidence that propylene glycol monomethyl ether, diethylene glycol monomethyl ether or diethylene glycol dimethyl ether causes testicular atrophy in mice. Teratological studies of EGM and EGdM revealed embryotoxic effects in mice. Images FIGURE 1. FIGURE 4. FIGURE 5. FIGURE 6. FIGURE 7. FIGURE 8. FIGURE 9. FIGURE 10. FIGURE 11. FIGURE 12. FIGURE 13. PMID:6499822

Nagano, K; Nakayama, E; Oobayashi, H; Nishizawa, T; Okuda, H; Yamazaki, K

1984-01-01

111

Experimental studies on toxicity of ethylene glycol alkyl ethers in Japan.  

PubMed

Past studies on the toxicological effects of ethylene glycol alkyl ethers as well as the recent data on these chemicals in Japan are reviewed. Only a few researchers have participated in the study of ethylene glycol alkyl ethers in Japan. The effects of ethylene glycol alkyl ethers on testis and embryotoxic effects of ethylene glycol monomethyl ether (EGM) have been studied, as has the teratogenicity of ethylene glycol dimethyl ether (EGdM). Studies on ethylene glycol alkyl ethers and related compounds administered to mice by oral gavage revealed the occurrence of testicular atrophy and decreased white blood cell count by EGM, EGdM, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether and ethylene glycol monoethyl ether acetate, and the toxicity was related to their chemical structure. On the other hand, ethylene glycol, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monophenyl ether, ethylene glycol monoacetate or ethylene glycol diacetate showed no such an effect. Studies on EGM using hamsters or guinea pigs revealed the occurrence of testicular atrophy similar to that observed in mice. In regard to the methyl ethers of other glycols, there is no convincing evidence that propylene glycol monomethyl ether, diethylene glycol monomethyl ether or diethylene glycol dimethyl ether causes testicular atrophy in mice. Teratological studies of EGM and EGdM revealed embryotoxic effects in mice. PMID:6499822

Nagano, K; Nakayama, E; Oobayashi, H; Nishizawa, T; Okuda, H; Yamazaki, K

1984-08-01

112

Consequences of the formation of 3,4-dimethyl-5-phenyl-1,3-oxazolidine on the analysis of ephedrines in urine by gas chromatography and a new method for confirmation as N-trifluoroacetyl-O-t-butyldimethylsilyl ether derivatives.  

PubMed

The compound 3,4-dimethyl-5-phenyl-1,3-oxazolidine can appear as an artifact during the gas chromatographic analysis of ephedrines. Its presence is a risk for doping control and forensic analyses. An evaluation about the consequences of its formation showed the possibility of a false positive for ephedrine, a false negative for pseudophedrine and increased uncertainty in the quantitative approach. Misinterpretations can be avoided with the observation of fragments m/z 56 and 71 in the ephedrine mass spectrum during GC-MS analysis and also by the formation of N-TFA-O-TBDMS derivatives prior to GC analysis. These N-TFA-O-TBDMS derivatives lead to an increase in the number and mass of diagnostic ions, meet the identification criteria, and provide an improvement in chromatographic resolution, allowing the separation of the ephedrines. PMID:21256502

Sardela, V F; Sardela, P D O; Pereira, H M G; Aquino Neto, F R

2011-03-01

113

14 CFR 171.321 - DME and marker beacon performance requirements.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 2010-01-01 false DME and marker beacon performance requirements. 171...System (MLS) § 171.321 DME and marker beacon performance requirements...ibr_locations.html. (b) MLS marker beacon equipment must meet the...

2010-01-01

114

Electron drift velocity and Townsend coefficient in DME-based gas mixtures  

NASA Astrophysics Data System (ADS)

Drift velocity and Townsend coefficients in pure DME, Ar-DME (50/50) and (80/20) and Ne-DME (50/50) and (80/20) mixtures have been measured for high and very high electric fields. The use of a modified pulsed Townsend technique allowed the study of electron transport close to the steady breakdown field of the gas.

Oettinger, Eva; Hildebrandt, Malte; Schmidt, Bernhard

115

DME The Department of Mechanical Engineering Faculty Recruitment Candidate  

E-print Network

FRC DME The Department of Mechanical Engineering Presents Faculty Recruitment Candidate Suveen.S.E. in Mechanical Engineering from Walla Walla University in 1998, and Ph.D. in Mechanical Engineering from Texas A. This presentation will pre- sent innovative processing approaches to the nanostructuring of Mg-alloys via "bottom

116

Ether lipids.  

PubMed

The naturally occurring 1-O-alkyl-sn-glycerols and their methoxylated congeners, 1-O-(2'-methoxyalkyl)-sn-glycerols, are biologically active compounds, ubiquitously found in nature as diacyl glyceryl ether lipids and phosphoether lipids. The chief objective of this article is to provide a comprehensive and up to date review on such ether lipids. The occurrence and distribution of these compounds in nature are extensively reviewed, their chemical structure and molecular variety, their biosynthesis and chemical synthesis and, finally, their various biological effects are described and discussed. An unprecedented biosynthesis of the 2'-methoxylated alkylglycerols is proposed. The first synthesis of enantiopure (Z)-(2'R)-1-O-(2'-methoxyhexadec-4'-enyl)-sn-glycerol, the most prevalent 2'-methoxylated type alkylglycerol present in cartilaginous fish, is described. It was accomplished by a highly convergent five step process. PMID:21635876

Magnusson, Carlos D; Haraldsson, Gudmundur G

2011-07-01

117

Orientation and Relaxation Study of Miscible Polystyrene/Poly(vinyl methyl ether) Blends  

E-print Network

Orientation and Relaxation Study of Miscible Polystyrene/Poly(vinyl methyl ether) Blends Christian of orientation of miscible polystyrene/poly- (vinyl methyl ether) (PS/PVME) blends containing between 50 and 100 the components. Monnerie et al. have observed that, in miscible polystyrene/poly(2,6-dimethyl-1,4-phenylene oxide

Pezolet, Michel

118

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

119

Bridging the dMe Gap with Ross 154  

NASA Astrophysics Data System (ADS)

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

Wargelin, Bradford

2008-10-01

120

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

NASA Astrophysics Data System (ADS)

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

Aoki, Shinya; Nakayama, Toshio

1997-08-01

121

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

PubMed Central

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

2013-01-01

122

Utilizing differential evolution (DE) technique to optimize operating conditions of an integrated thermally coupled direct DME synthesis reactor  

Microsoft Academic Search

According to global requirements to DME as an alternative environment friendly fuel and also regarding the positive effects of employing multifunctional auto-thermal reactors as novel concept in process intensification, direct DME synthesis was coupled with dehydrogenation of cyclohexane in a thermally coupled heat exchanger reactor composed of two separated sides for exothermic and endothermic reactions in our previous study. DME

R. Vakili; P. Setoodeh; E. Pourazadi; D. Iranshahi; M. R. Rahimpour

2011-01-01

123

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

124

Rate constant calculations of H-atom abstraction reactions from ethers by H?2 radicals.  

PubMed

In this work, we detail hydrogen atom abstraction reactions from six ethers by the hydroperoxyl radical, including dimethyl ether, ethyl methyl ether, propyl methyl ether, isopropyl methyl ether, butyl methyl ether, and isobutyl methyl ether, in order to test the effect of the functional group on the rate constant calculations. The Møller-Plesset (MP2) method with the 6-311G(d,p) basis set has been employed in the geometry optimizations and frequency calculations of all of the species involved in the above reaction systems. The connections between each transition state and the corresponding local minima have been determined by intrinsic reaction coordinate calculations. Energies are reported at the CCSD(T)/cc-pVTZ level of theory and include the zero-point energy corrections. As a benchmark in the electronic energy calculations, the CCSD(T)/CBS extrapolation was used for the reactions of dimethyl ether + H?2 radicals. A systematic calculation of the high-pressure limit rate constants has been performed using conventional transition-state theory, including asymmetric Eckart tunneling corrections, in the temperature range of 500-2000 K. The one dimensional hindrance potentials obtained at MP2/6-311G(d,p) for the reactants and transition states have been used to describe the low frequency torsional modes. Herein, we report the calculated individual, average, and total rate constants. A branching ratio analysis for every reaction site has also been performed. PMID:24483837

Mendes, Jorge; Zhou, Chong-Wen; Curran, Henry J

2014-02-27

125

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

126

Synthesis of Enol Methyl Ethers of 3Acetyl6,6-dimethyltetrahydrothiopyran-2,4-dione and Their Reactions with Amines  

Microsoft Academic Search

The reaction of 3-acetyl-6,6-dimethyltetrahydrothiopyran-2,4-dione with diazomethane furnishes a mixture of 3-acetyl-6,6-dimethyl-4-methoxy-5,6-dihydro-2H-thiopyran-2-one and 3-acetyl-6,6-dimethyl- 2-methoxy-5,6-dihydro-2H-thiopyran-4-one in 2:3 ratio, whereas in reaction with dimethyl sulfate in the presence of potassium carbonate forms a mixture of the same products in 9:1 ratio. In both reactions the overall yield of ethers amounts to 50%. Treating of regioisomeric enol methyl ethers with pyrrolidine, o-toluidine, and

T. A. Zheldakova; M. V. Budnikova; D. B. Rubinov

2003-01-01

127

Performance of an Ar-DME imaging photoelectric polarimeter  

NASA Astrophysics Data System (ADS)

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

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

2012-09-01

128

Crown ethers in graphene.  

PubMed

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

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

2014-01-01

129

21 CFR 172.133 - Dimethyl dicarbonate.  

...additive contains not more than 2,000 ppm (0.2 percent) dimethyl carbonate as determined by a method entitled “Gas Chromatography Method for Dimethyl Carbonate Impurity in Dimethyl Dicarbonate,” which is incorporated by reference in...

2014-04-01

130

DIMETHYL METHYLPHOSPHONATE AS METHYLATING REAGENT  

Microsoft Academic Search

The methylating properties of dimethyl methylphosphonate have been investigated. Aromatic mono- and polycarboxylic acids were converted into their methyl esters by heating with dimethyl methylphosphonate. Similarly phenols or amines gave their respective O- or N-methyl derivatives. The sodium salts of sulfinic acids also reacted yielding sulfones in high yield.

Peter Sutter; Claus D. Weis

1978-01-01

131

Observations of Flare Activity on Selected DME Flare Stars  

NASA Astrophysics Data System (ADS)

Optical and ultraviolet spectroscopy can enable the assessment of the physical conditions characterizing a stellar flare atmosphere and thereby potentially elucidate the possible radiative and hydrodynamic transport mechanisms operative during stellar flares. Observations of flares on M dwarf stars offers the opportunity to obtain detailed information on a solar-like phenomenon as it presumably occurs on many stars, but can presently only be observed on the cool dMe stars due to the highly favorable contrast between the UV and near UV bright flare emission and the faint quiescent background. We therefore propose to acquire timeresolved, low dispersion, large aperture SWP and LWR observations simultaneously with moderate resolution (3-4A) spectrophotometric optical observations of stellar flare events. We also will attempt to coordinate simultaneous VLA (radio corona) observations. We intend to monitor two highly flare active systems; the binary UV Ceti (GL65AB) system and the single flare star YZ CMi (GL 285). We wish to ascertain the dominant radiative transport mechanism that gives rise to the UV and optical continuum emission during flares as well as assess the relative energy balance in these wavelength regions. Furthermore, we will utilize density diagnostics and emission mesure analysis techniques developed for solar observations. In addition, we will infer flare X-ray luminosities from the enhancement of the He II 1640 recombination line. The UV data and inferred X-ray data will ultimately be used to determine the applicability of flare loop models. All data obtained in this program will be used as input for the construction of semiempirical flare atmospheres.

Giampapa, Mark S.

132

Genotoxicity of glycol ethers.  

PubMed Central

The genetic toxicology of glycol ethers is reviewed. Ethylene glycol monomethyl ether (EGME) and diglyme have been more extensively studied than other members of this series. Most results indicate a lack of genotoxic potential, but certain tests have yielded positive responses with certain compounds. Ethylene glycol monoethyl ether (EGEE) induced sister chromatid exchanges and chromosomal aberrations in cultured cells. Both EGME and diglyme induced mouse sperm head morphological changes, male rat weak dominant lethal mutations and marked, but reversible, loss of male rat fertility. PMID:6541999

McGregor, D B

1984-01-01

133

Functional and expression analysis of the metal-inducible dmeRF system from Rhizobium leguminosarum bv. viciae.  

PubMed

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

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

2013-10-01

134

Influence of gas composition on the combustion and efficiency of a homogeneous charge compression ignition engine system fuelled with methanol reformed gases  

Microsoft Academic Search

A homogeneous charge compression ignition (HCCI) engine system fuelled with dimethyl ether (DME) and methanol-reformed gas (MRG), both produced from methanol by onboard reformers using exhaust heat, has been proposed in previous research. Adjusting the proportions of DME and MRG with different ignition properties effectively controlled the ignition timing and load in HCCI combustion. The use of the single liquid

T Shudo

2008-01-01

135

Binding of ether and carbonyl oxygens to lithium ion  

SciTech Connect

The electrolyte for a lithium battery is a lithium salt (e.g. lithium Perchlorate) dissolved in an organic solvent or a mixture of organic solvents. The conductivity in these electrolytes is ionic and needs to be as high as possible to efficiently remove energy from the battery. The diffusion coefficient of the solvated ion in liquid electrolytes is inversely dependent on the radius of the salvation sphere. Consequently conductivity will increase with a decrease in the size of the salvation shell. The size of the salvation shell is determined by the size and coordination number of the solvent molecules. The types of organic solvents in electrolytes used in lithium battery applications are usually differentiated based on their perceived solvation properties. These solvents are often small, oxygen containing organic molecules which move with the Li{sup +} ions. This paper calculates the binding energies of some of these solvents to Li{sup +} using molecular quantum mechanics (MQM) techniques. The binding energies of the various solvents to Li{sup +} may determine which solvents will be preferentially bound to the ion. In liquid organic electrolytes, then, it will be the identity of the solvent and the coordination number which most affect the conductivity; the binding energies determine both of these properties. Carbonyl oxygens which occur in formaldehyde, acetaldehyde, acetone, ethylene carbonate and propylene carbonate have different Li{sup +} bonding properties than do the ether oxygens which occur in water, dimethyl ether and diethyl ether. Polymer solvents for the lithium salts such as the polyethers have chains which are too long to move with the binding energies then serve as the basis for a different Li{sup +} transport. Dimethyl ether and diethyl ether serve both as solvents and models for the polyethers.

Blint, R.J. [Physical Chemistry Dept., Warren, MI (United States)

1994-12-31

136

Determination of the ?-Charge Distribution of the DMe-DCNQI Molecule in (DMe-DCNQI) 2 M, M=Li, Ag, and Cu  

NASA Astrophysics Data System (ADS)

Solid state high-resolution NMR of 1H and 13C along with 15N is analyzed to investigate the electronic states of the charge transfer salts (DMe-DCNQI)2M, (M=Li, Ag, and Cu). We determined the spin/charge distribution in a DMe-DCNQI molecule of the Li-salt from the Knight shifts at each atom on the molecule. It is found that the obtained charge distribution is similar to the theoretical prediction. The charge density on the DCNQI molecules of the Ag-salt is found to be smaller by 20% than the Li-salt, which could be an origin of differences from the Li-salt. This result is consistent with the first principle calculations (Miyazaki and Terakura, Phys. Rev. B 54, 10452, 1996).

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

2006-02-01

137

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

138

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

E-print Network

http://informatics.medicine.dal.ca http://dme.medicine.dal.ca www.medicine.dal.ca www at the level of Assistant Professor. Medical Informatics in the Faculty of Medicine was established in 1996 in the Medical Informatics Program, program development in the Faculty of Medicine and in the Health Informatics

Adl, Sina

139

Diesel emission improvements by the use of oxygenated DME/diesel blend fuels  

NASA Astrophysics Data System (ADS)

A kind of oxygenate fuel, DME, has been proposed and tested for use with diesel fuel as a means of reducing exhaust emissions. The addition of DME to diesel fuel results in the decrease of the lower calorific value, aromatics fraction and kinematic viscosity of blend fuels. Simultaneously, cetane number, C/H ratio and oxygen content of the blends are enhanced, which has some favorable effects on the combustion and emission of the blends with 10%, 20% and 30% DME by mass. The study on the performance and emissions of the diesel/DME blend is conducted in a DI engine. The emission characteristics of four fuels are determined in a diesel engine. At high loads, the blends reduce smoke significantly with a little penalty on CO and HC emissions compared to diesel fuel. NO x and CO 2 emissions of the blends are decreased somewhat. At low loads, the blends have slight effects on smoke reduction due to overall leaner mixture. The results indicate the potential of diesel reformation for clean combustion in diesel engines.

Ying, Wang; Longbao, Zhou; Hewu, Wang

140

Analysis of the Database of Theses and Dissertations from DME/UFSCAR about Astronomy Education  

NASA Astrophysics Data System (ADS)

The paper presents a brief analysis of the "Database of Theses and Dissertations about Astronomy Education" from the Department of Teaching Methodology (DME) of the Federal University of São Carlos(UFSCar). This kind of study made it possible to develop new analysis and statistical data, as well as to conduct a rating of Brazilian institutions that produce academic work in the area.

Rodrigues Ferreira, Orlando; Voelzke, Marcos Rincon

2013-11-01

141

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

142

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

143

Glycol Ethers As Groundwater Contaminants  

NASA Astrophysics Data System (ADS)

Ether derivatives of dihydroxy alcohols, which are formed from ethylene or propylene, comprise an important group of groundwater contaminants known as glycol ethers. Compounds in this group are used as solvents, cleaning agents, and emulsifiers in many chemical products and manufacturing operations. Glycol ethers have been associated with a variety of toxic effects, and some compounds in the group are relatively potent teratogens. The limited information available suggests that glycol ethers are contaminants in groundwater, especially in anaerobic plumes emanating from disposal of mixed industrial and household waste. Most methods used to analyze groundwater samples cannot adequately detect ?g/? (ppb) concentrations of glycol ethers, and the existing methods perform worst for the most widely used and toxic species. A new method capable of analyzing ?g/? concentrations of glycol ethers was recently developed, and its use is recommended for groundwater samples where glycol ethers are likely to be present.

Ross, Benjamin; Johannson, Gunnar; Foster, Gregory D.; Eckel, William P.

1992-01-01

144

Simple, Scalable, Script-based, Science Processor for Measurements - Data Mining Edition (S4PM-DME)  

NASA Astrophysics Data System (ADS)

The S4PM-DME is the Goddard Earth Sciences Distributed Active Archive Center's (GES DAAC) web-based data mining environment. The S4PM-DME replaces the Near-line Archive Data Mining (NADM) system with a better web environment and a richer set of production rules. S4PM-DME enables registered users to submit and execute custom data mining algorithms. The S4PM-DME system uses the GES DAAC developed Simple Scalable Script-based Science Processor for Measurements (S4PM) to automate tasks and perform the actual data processing. A web interface allows the user to access the S4PM-DME system. The user first develops personalized data mining algorithm on his/her home platform and then uploads them to the S4PM-DME system. Algorithms in C and FORTRAN languages are currently supported. The user developed algorithm is automatically audited for any potential security problems before it is installed within the S4PM-DME system and made available to the user. Once the algorithm has been installed the user can promote the algorithm to the "operational" environment. From here the user can search and order the data available in the GES DAAC archive for his/her science algorithm. The user can also set up a processing subscription. The subscription will automatically process new data as it becomes available in the GES DAAC archive. The generated mined data products are then made available for FTP pickup. The benefits of using S4PM-DME are 1) to decrease the downloading time it typically takes a user to transfer the GES DAAC data to his/her system thus off-load the heavy network traffic, 2) to free-up the load on their system, and last 3) to utilize the rich and abundance ocean, atmosphere data from the MODIS and AIRS instruments available from the GES DAAC.

Pham, L. B.; Eng, E. K.; Lynnes, C. S.; Berrick, S. W.; Vollmer, B. E.

2005-12-01

145

Development of a VOR/DME model for an advanced concepts simulator  

NASA Technical Reports Server (NTRS)

The report presents a definition of a VOR/DME, airborne and ground systems simulation model. This description was drafted in response to a need in the creation of an advanced concepts simulation in which flight station design for the 1980 era can be postulated and examined. The simulation model described herein provides a reasonable representation of VOR/DME station in the continental United States including area coverage by type and noise errors. The detail in which the model has been cast provides the interested researcher with a moderate fidelity level simulator tool for conducting research and evaluation of navigator algorithms. Assumptions made within the development are listed and place certain responsibilities (data bases, communication with other simulation modules, uniform round earth, etc.) upon the researcher.

Steinmetz, G. G.; Bowles, R. L.

1984-01-01

146

Measurement of magnetic fields in dMe stars using the Zeeman effect  

NASA Astrophysics Data System (ADS)

While it is suggested that dMe stars have strong magnetic fields, there are only few accurate measurements of the magnetic fields because of faintness of these stars and requirement of high-resolution spectroscopy. We carried out high-resolution spectroscopic observations using HIDES, and measured the strength of the magnetic fields in three dMe stars. As a result, we have obtained typical values of the field strength and the filling factor in these stars. One of these stars was revealed to have parameters inconsistent with those previously measured, which suggests a possibility of long-term variability of the magnetic field strength. We expect future continuous observations to reveal the stellar magnetic variability in the long term.

Ohashi, Hiroyuki

2004-06-01

147

Synthesis of oxygenate products for high volume fuels applications. Quarterly technical progress report, November 1, 1994--January 31, 1995  

SciTech Connect

The objective of this project is to develop high yield syntheses of oxygenate products that are liquid at room temperature using as starting materials dimethy ether (DME) or methanol. The identified products include: Dimethyl Carbonate (DMC), 1,1-Dimethoxyethane (DMOE), C{sub 2}{sup +} Alcohols/Ethers (C{sub 2}AE). The technical strategy is outlined below: (A) Synthesis of DMC via oxidative carbonylation of DME instead of methanol. Since this synthesis would not co-produce water as a byproduct, there is a potential for very high DME conversions in contrast to the low (ca 20%) conversions obtained in conventional plants. Technical emphasis will be placed on development of a supported copper catalyst with a capability for cleavage of DME into its chemisorbed organic moieties. (B) Synthesis of 1,1-dimethoxymethane (DMOE) from acetylene/CO/H{sub 2} process streams obtained from commercial methane oxidative pyrolysis processes. In the overall processing scheme the syngas would be converted to DME. The wet acetylene stream would be partially condensed to retain an equivalent of water and then condensed with DME to produce EMOE. (C) Direct conversion of DME or DME/methanol to ethanol/propanol or their methyl ethers. Under the influence of functionalized alcohol condensation catalysts developed exclusively at Amoco it should be possible to achieve direct conversion of dimethyl ether (or methanol) to ethanol/propanol and/or the methyl ethers of these alcohols. Although this reaction is not currently known, a combination of key catalyst components from identified systems should result in a DME conversion catalyst to C{sub 2}+ oxygenates. (D) Reaction of DME or acetylene with synthesis gas (CO/H{sub 2}) or methanol. A variety of catalysts will be tested for conversion of acetylene/CO/H{sub 2} or acetylene/methanol to propylene and conversion of DME/CO/H{sub 2} or DME/methanol to dimenthyoxymethane (DMM) and/or other oxygenates.

NONE

1995-03-08

148

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

E-print Network

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

Netzach Farbiash; Raphael Steinitz

2005-01-09

149

Operation of microstrip gas counters with DME-based gas mixtures  

NASA Astrophysics Data System (ADS)

This paper reports on the operation of MicroStrip Gas Counters (MSGC) with several dimethylether (DME)-based gas mixtures. We present measurements of signal amplitude, detection efficiency and spatial resolution for minimum ionizing particles. We also show measurements of electron drift velocity and transverse diffusion coefficient in the counting gases considered. These results are discussed regarding the use of MSGC's for tracking at high-energy physics experiments that have to deal with high particle rates.

Bouhali, O.; Udo, F.; Van Doninck, W.; Van Lancker, L.; Vander Velde, C.; Vanlaer, P.; Zhukov, V.; Beaumont, W.; Beckers, T.; De Troy, J.; Van Dyck, C.; Verbeure, F.

150

Experimental investigation on flame pattern formations of DME-air mixtures in a radial microchannel  

SciTech Connect

Flame pattern formations of premixed DME-air mixture in a heated radial channel with a gap distance of 2.5 mm were experimentally investigated. The DME-air mixture was introduced into the radial channel through a delivery tube which connected with the center of the top disk. With an image-intensified high-speed video camera, rich flame pattern formations were identified in this configuration. Regime diagram of all these flame patterns was drawn based on the experimental findings in the equivalence ratio range of 0.6-2.0 and inlet velocity range of 1.0-5.0 m/s. Compared with our previous study on premixed methane-air flames, there are several distinct characteristics for the present study. First, Pelton-wheel-like rotary flames and traveling flames with kink-like structures were observed for the first time. Second, in most cases, flames can be stabilized near the inlet port of the channel, exhibiting a conical or cup-like shape, while the conventional circular flame was only observed under limited conditions. Thirdly, an oscillating flame phenomenon occurred under certain conditions. During the oscillation process, a target appearance was seen at some instance. These pattern formation characteristics are considered to be associated with the low-temperature oxidation of DME. (author)

Fan, Aiwu [School of Energy and Power Engineering, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan (China); Institute of Fluid Science, Tohoku University, Aoba-ku, Sendai (Japan); Maruta, Kaoru; Nakamura, Hisashi [Institute of Fluid Science, Tohoku University, Aoba-ku, Sendai (Japan); Kumar, Sudarshan [Aerospace Engineering Department, IIT Bombay, Powai, Mumbai (India); Liu, Wei [School of Energy and Power Engineering, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan (China)

2010-09-15

151

Comparative study of the vacuum ultraviolet absorption and photoelectron spectra of some simple ethers and thioethers  

Microsoft Academic Search

The vacuum ultraviolet absorption (from 220 to 120 nm) and photoelectron (from 6 to 21 eV) spectra of the following molecules are compared: tetrahydropyran, tetrahydrothiopyran, methylvinylether, methylvinylthioether, dihydropyran, and 4,4-dimethyl-2,3-dihydrothiopyran. The great similarity between the photoelectron spectra of related ethers and thioethers is stressed. In the case of saturated thioethers the corresponding ultraviolet spectra are, however, very different, showing that

A. A. Planckaert; J. Doucet; C. Sandorfy

1974-01-01

152

Methanesulphonic acid, dimethyl sulphoxide and dimethyl sulphone in aerosols  

NASA Astrophysics Data System (ADS)

Aerosol concentrations of methanesulphonic acid (MSA), dimethyl sulphoxide (DMSO), dimethyl sulphone (DMSO 2) and major anions have been measured from landbased stations (principally Plymouth, Devon, U.K.) and various shipboard stations in the North Sea and North Atlantic Ocean. Aerosol samples collected between July 1985 and July 1987 are analyzed both in terms of their back trajectories, and variation with time. These analyses suggest that NO 3 and NSSS are anthropogenic in origin while DMSO 2 appears to have a maritime source. MSA concentrations are highest in air masses with both oceanic and anthropogenic influences. DMSO, MSA, and DMSO 2 all show seasonal cycles, with concentrations similar to previous published results. MSA was found to be concentrated on sub-?m particles. Rainfall MSA concentrations were measured over 2 years at Norwich and were found to exhibit a similar seasonality to the aerosol MSA concentrations.

Watts, S. F.; Brimblecombe, P.; Watson, A. J.

153

Bacterial degradation of glycol ethers.  

PubMed

Assimilation of ethyleneglycol (EG) ethers by polyethyleneglycol-utilizing bacteria was examined. Ethyleneglycol ether-utilizing bacteria were also isolated from soil and activated sludge samples by enrichment-culture techniques. Three strains (4-5-3, EC 1-2-1 and MC 2-2-1) were selected and characterized as Pseudomonas sp. 4-5-3, Xanthobacter autotrophicus, and an unidentified gram-negative, non-spore-forming rod respectively. Their growth characteristics were examined: Pseudomonas sp. 4-5-3 assimilated EG (diethyleneglycol, DEG) monomethyl, monoethyl and monobutyl ethers, DEG, propanol and butanol. X. autotrophicus EC 1-2-1 grew well on EG monoethyl and monobutyl ethers, EG and primary alcohols (C1-C4), and slightly on EG monomethyl ether. The strain MC 2-2-1 grew on EG monomethyl ether, EG, primary alcohols (C1-C4), and 1,2-propyleneglycol (PG). The mixed culture of Pseudomonas sp. 4-5-3 and X. autotrophicus EC 1-2-1 showed better growth and improved degradation than respective single cultures towards EG monomethyl, monoethyl or monobutyl ethers. Intact cells of Pseudomonas sp. 4-5-3 degraded various kinds of monoalkyl ethers, which cannot be assimilated by the strain. Metabolic products were characterized from reaction supernatants of intact cells of Pseudomonas sp. 4-5-3 with EG or DEG monoethyl ethers: they were analyzed by thin-layer chromatography and GC-MS and found to be ethoxyacetic acid and ethoxyglycoxyacetic acid. Also, PG monoalkyl ethers (C1-C4), dipropyleneglycol monoethyl and monomethyl ethers and tripropyleneglycol monomethyl ether were assimilated by polypropyleneglycol-utilizing Corynebacterium sp. 7. PMID:8597556

Kawai, F

1995-12-01

154

Searching for solvent cavities via electron photodetachment: The ultrafast charge-transfer-to-solvent dynamics of sodide in a series of ether solvents  

SciTech Connect

It was recently predicted by simulations and confirmed by neutron diffraction experiments that the structure of liquid tetrahydrofuran (THF) contains cavities. The cavities can be quite large and have a net positive electrostatic potential, so they can serve as pre-existing traps for excess electrons created via photodetachment from various solutes. In this paper, we use electron photodetachment via charge-transfer-to-solvent (CTTS) excitation of sodide (Na{sup -}) to probe for the presence of pre-existing cavities in a series of ether solvents: THF, diethyl ether, 1,2-dimethoxyethane (DME), and diglyme (DG). We find that electrons photodetached from sodide appear after a time delay with their equilibrium spectrum in all of these solvents, suggesting that the entire series of ethers contains pre-existing solvent cavities. We then use the variation in electron recombination dynamics with CTTS excitation wavelength to probe the nature of the cavities in the different ethers. We find that the cavities that form the deepest electron traps turn on at about the same energy in all four ether solvents investigated, but that the density of cavities is lower in DG and DME than in THF. We also examine the dynamics of the neutral sodium species that remains following CTTS photodetachment of an electron from sodide. We find that the reaction of the initially created gas-phase-like Na atom to form a (Na{sup +},e{sup -}) tight-contact pair occurs at essentially the same rate in all four ether solvents, indicating that only local solvent motions and not bulk solvent rearrangements are what is responsible for driving the partial ejection of the remaining Na valence electron.

Larsen, Molly C.; Schwartz, Benjamin J. [Department of Chemistry and Biochemistry, University of California-Los Angeles, Los Angeles, California 90095-1569 (United States)

2009-10-21

155

Relative potency of four ethylene glycol ethers for induction of paw malformations in the CD-1 mouse.  

PubMed

Time-mated CD-1 mice were orally dosed on gestation day 11 (plug = 0) with distilled water (control) or one of four glycol ethers at a dose of 4 mmol/kg: ethylene glycol monomethyl ether (EGME, 304 mg/kg), ethylene glycol dimethyl ether (EGdiME, 361 mg/kg), diethylene glycol dimethyl ether (diEGdiME, 537 mg/kg), triethylene glycol dimethyl ether (triEGdiME, 713 mg/kg). Fetuses were collected on gestation day 18, weighed, and examined for gross external malformations. Fetuses were cleared and stained to examine paws. There were no signs of treatment-related maternal toxicity, and intrauterine survival was unaffected by glycol ether treatments. Fetal body weights were significantly reduced only in litters treated with EGdiME. There was no treatment-related pattern of gross external malformations other than paw defects. Only triEGdiME failed to produce a significant incidence of malformations. Paw defects were present in 87.5% of EGME-treated litters (68.5% of fetuses), 86.7% of EGdiME-treated litters (33.8% of fetuses), and 77.8% of diEGdiME-treated litters (39.7% of fetuses). Hindpaw defects predominated over forepaw, and syndactyly was the most common malformation. The incidences of oligodactyly and short digits were also significantly increased. The similarity of malformations produced by these methyl-substituted glycol ethers is proposed to be attributable to in vivo conversion to a common teratogen, methoxyacetic acid. PMID:3629512

Hardin, B D; Eisenmann, C J

1987-06-01

156

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

SciTech Connect

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

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

1994-12-31

157

VLBI observations of YZ CMi - A single dMe star  

NASA Astrophysics Data System (ADS)

The quiescent (nonflaring) radio emission of the single dMe star YZ CMi was detected in an intercontinental VLBI experiment at 1.7 GHz. A radio diameter of the star of 1.0 + or - 0.5 mas was found, statistically compatible with zero. The formal value corresponds to 1.7 optical stellar diameters and yields a brightness temperature of 1.7 x 10 exp 9 K with a lower limit of 4 x 10 exp 8 K. This high brightness strongly suggests emission by nonthermal particles by the gyrosynchrotron mechanism or an incoherent process.

Benz, A. O.; Alef, W.

1991-12-01

158

Magnetic susceptibility of (DMe-DCNQI) 2Li 1- xCu x  

NASA Astrophysics Data System (ADS)

We measured the static spin susceptibility of the quasi-one-dimensional molecular conductors, (DMe-DCNQI) 2Li 1- xCu x (0? x?1). We separated the susceptibility component due to itinerant electrons from that due to local magnetic moments by assuming that the temperature dependence of the latter component obeys the Curie-Weiss law. From the temperature dependence of the former component, we conclude that the ground state of this system is nonmagnetic for x?0.14 and paramagnetic for 0.17? x. The phase boundary thus determined is consistent with the phase diagram already determined by resistivity measurements.

Yamamoto, T.; Tajima, H.; Kato, R.

2000-04-01

159

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

160

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.) PMID:22589436

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

2012-01-01

161

amine methanol, ether . Amine amine CO2  

E-print Network

IP [2012] 7 C O 2 (CO2) . CO2 amine methanol, ether . Amine amine CO2 CO2 .Amine CO2 (functional group) amine amine+ +promoter .Amine CO2 CO2 . . , methanol ether methanol, ether promoter CO2 CO2 H2S, COS CO2 . Methanol rectisol process, di-methylene ether polypropylene glycol selexol (-30oC) . CO2

Hong, Deog Ki

162

Gamma-pyrone derivatives, kojic acid methyl ethers from a marine-derived fungus Alternaria [correction of Altenaria] sp.  

PubMed

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 fungus Alternaria sp. collected from the surface of the marine green alga Ulva pertusa. The structures were assigned on the basis of comprehensive spectroscopic analyses. Each isolate was tested for its tyrosinase inhibitory activity. Kojic acid (3) was found to have significant tyrosinase inhibitory activity, but compounds 1, 2, and 4 were found to be inactive. PMID:12934644

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

2003-07-01

163

210 X 297mm Dimethyl Carbonate  

E-print Network

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

Hong, Deog Ki

164

Orbital- and band-dependent susceptibility in a ?-d hybrid electronic system, (DMe-DCNQI) 2Cu  

NASA Astrophysics Data System (ADS)

A ?-d hybrid electronic system, (DMe-DCNQI)2Cu, where the ? orbital of the organic molecule, DMe-DCNQI, is strongly hybridized with the d xy orbital of Cu, has been studied by 15N and 13C NMR at three sites. The analysis of Knight shift, K, and local spin susceptibilities in the ? and d orbitals was carried out separately. The ? and d spin susceptibilities were found to be quite different in magnitude and temperature dependence. Moreover, the Knight shift was separated into those of two constituent bands; a one-dimensional ? band and a three-dimensional ?-d band. The relative weight of the band susceptibilities is strongly temperature dependent.

Kawamoto, A.; Miyagawa, K.; Kanoda b, K.

2000-06-01

165

HS 1136+6646: A New Short Period DAO + dMe System  

NASA Astrophysics Data System (ADS)

We have obtained time resolved optical spectroscopy of the Hamburg-Schmidt Survey source HS1136+6646, identified by Heber et al. (1996) as a DAO + K system. Our results reveal this to be a short period DAO + dMe system, exhibiting a strong reflection effect. Two consecutive nights of observation yield a partial radial velocity curve for the companion as well as the reflex motion of the white dwarf. The orbital period is apparently less than a day and the semi-amplitude of the secondary greater than 85 km/s. Strong H I and He I emission lines from the irradiated hemisphere of the secondary are present as well as weaker lines due to Ca II and Mg II. The emission lines disappear near inferior conjunction, as does the He II photospheric feature of the white dwarf, indicating a highly inclined system and the possibility of an eclipse of the white dwarf. Near IR JHK spectroscopy obtained at the MMT shows the secondary to be an dMX star. Far UV observations obtained with the Far Ultraviolet Spectroscopic Explorer (FUSE) confirm the radial velocity variations of the white dwarf and provide preliminary estimates of its effective temperature and gravity. This system appears to be similar to DAO + dMe systems such as REJ 1016+050, REJ 2013+400 and REJ 0720+318 and possibly the eclipsing system PG1413+015.

Holberg, J. B.; Sing, D.; Barstow, M. A.; Good, S.

166

VLBI observations of two single dMe stars: spatial resolution and astrometry  

NASA Astrophysics Data System (ADS)

We report on 3.6 cm VLA and VLBA observations of YZ CMi and AD Leo, two nearby dMe stars. We resolve YZ CMi and can fit a circular symmetrical gaussian component of FWHP of 0.98 +/-0.2 mas, corresponding to an extent of the corona above the photosphere of 1.77 x 1010 +/-8.8 x 109 cm or 0.7 +/-0.3 R_star (R_star refers to the photospheric radius). We obtain an estimate of the brightness temperature of 7.3 x 107 K, which is consistent with that expected from gyrosynchrotron emission. For AD Leo the emitting region is unresolved. We therefore set a conservative upper limit to its diameter of 1.8 times the photosphere diameter, which leads to an extent of the corona above the photosphere of <2.8x 1010cm or <0.8 R_star . We compare the radio emitting dMe stars with measured sizes with the Sun and conclude that these active stars have much more extended coronal radio emission than the Sun. The VLBA position of YZ CMi has been found to differ by 32 mas from the positions calculated from the Hipparcos catalogue. The discrepancy is caused by large errors in the listed proper motion. An improved value is given.

Pestalozzi, M. R.; Benz, A. O.; Conway, J. E.; Güdel, M.

2000-01-01

167

Exogenous Ether Lipids Predominantly Target Mitochondria  

Microsoft Academic Search

Ether lipids are ubiquitous constituents of cellular membranes with no discrete cell biological function assigned yet. Using fluorescent polyene-ether lipids we analyzed their intracellular distribution in living cells by microscopy. Mitochondria and the endoplasmic reticulum accumulated high amounts of ether-phosphatidylcholine and ether-phosphatidylethanolamine. Both lipids were specifically labeled using the corresponding lyso-ether lipids, which we established as supreme precursors for lipid

Lars Kuerschner; Doris Richter; Hans Kristian Hannibal-Bach; Anne Gaebler; Andrej Shevchenko; Christer S. Ejsing; Christoph Thiele

2012-01-01

168

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

169

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

170

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

Microsoft Academic Search

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

Kouichi Urata; Naotake Takaishi

1996-01-01

171

A Simplified Method for the Analysis of Interference from JTIDS Radio Networks to DME Aeronautical Radionavigation Systems  

NASA Astrophysics Data System (ADS)

Three distinct mechanisms of interference of JTIDS transmissions to DME are investigated: false interrogator triggering, transponder overloading and desensitization of either transponder or interrogator receivers. The effect of transponder overloading due to JTIDS transmissions is found the most serious. An analytical method is provided which relates the transponder reply efficiency to the load of the interrogations received in the presence of JTIDS transmissions.

Houdzoumis, Vassilios A.

172

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

173

A framework for using optical sensors in nanomeasuring machines over I++/DME  

NASA Astrophysics Data System (ADS)

This paper discusses the problem of integrating optical sensors into CMMs. First the basic concept of optical sensors is briefly introduced as well as the targeted measurement implementation standard, I++DME, and the Optical Sensor Interface Standard, which is still seldom used but is gaining acceptance. A novel generic software framework is introduced which helps to simplify the use of optical sensors in CMMs. To demonstrate the feasibility of integrating an optical sensor into a CMM, the framework has been successfully implemented around a white light interferometer, in which the sensor system is mounted in an ultra-precision CMM. The actual process control and data analysis was done using a third-party metrology application, which does not normally support either ultra-precision CMMs or optical sensors.

Sparrer, E.; Machleidt, T.; Hausotte, T.; Franke, K.-H.; Manske, E.

2012-07-01

174

FUSE Observations of the Classical dMe Flare Star UV Ceti  

NASA Astrophysics Data System (ADS)

We propose to use FUSE in the TTAG observing mode to observe the classical dMe flare star UV Ceti. This is one of the most active of all flare stars and so provides the best opportunity of obtaining large flares, with enough photons to examine the time history of the event. FUSE is an excellent instrument for investigating flares, since the prominent CIII and O IV lines are formed in the transition region and lower corona, where the flare events are thought to originate. These lines not only provide valuable density diagnostics, but are also sufficiently resolved by FUSE to allow an investigation of turbulence and flows during the larger events. The goals of the program are to understand (1) the dynamics of the flares, (2) the relation between flare occurrence rate and energy released, (3) the physical characteristics within the flare region, (4) the properties of the continuum emission and 5) the characteristics of the quiescent emission.

Robinson, L.

175

X-ray and EUV Flares on Active dMe Stars  

NASA Astrophysics Data System (ADS)

We have detected several X-ray and EUV (Extreme Ultraviolet) flares on two highly active dMe stars, YY Gem and AU Mic, using the ROSAT XRT and WFC all-sky survey observations. There was one impulsive X-ray and a simultaneous EUV flare on YY Gem, over a period of two days, with peak X-ray and EUV luminosities 1.6 × 1030 erg/s and 3 × 1029 erg/s, respectively. For AU Mic we observed one very large impulsive X-ray flare and a simultaneous EUV flare, with peak luminosities 2.5 × 1030 erg/s and 2.5 × 1029 erg/s, respectively. These flares were accompanied by several other smaller flares. It appears that the two stars were undergoing intense flare-activity over a period of two days during September 28-29, 1990.

Tsikoudi, Vassiliki

176

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

177

The activity rate of dMe flare stars in the Hyades Open Cluster  

NASA Astrophysics Data System (ADS)

We shall perform extended pointed observations of 2 regions of the Hyades open cluster to observe UV flare activity on dMe field stars. We expect to detect significant UV activity from at least 20 of these stars in each field, such that we can perform a statistical analysis of the typical time-scales and amplitudes of the observed emission variability. M-type stars are the most ubiquitous class of stellar object in our galaxy and they exhibit chromospheric and transition region behavior that is similar to our Sun, albeit with a far higher level of magnetic activity. These GALEX obsevrations will provide an important data-base of extreme solar-like activity recorded with an unprecedented time-resolution of < 0.1 seconds.

Welsh, Barry

178

Diagonal Mesh Equivalent (DME) for the calculation of the hysteresis losses in electrical machines  

NASA Astrophysics Data System (ADS)

The Magnetic Equivalent Circuits (MECs) technique is a powerful tool for machine analysis and power losses computation. Here, use is made of the Diagonal Mesh Equivalent (DME) to solve the equivalent electrical circuit for the branch fluxes to be easily computed and related to the machine compartments of technical interest. These are represented by the air gap, stator and rotor to name a few. Hysteresis loops have been computed, along with the static power losses, for assigned stator thicknesses and compared to ones alternatively obtained by the Modified Scalar Preisach Model. This study is especially aimed at giving improved issues to those who are engaged in the design of magnetic components for electrical machines.

Vergura, S.; Carpentieri, M.; Lattarulo, F.

2014-02-01

179

Cleavage of different ether bonds in butyl glycidyl ether and allyl glycidyl ether by K ?, K +(15-crown-5) 2  

Microsoft Academic Search

The kind of substituent in alkyl glycidyl ethers affects the course of their reaction with K?, K+(15-crown-5)2. The cyclic oxirane ring is exclusively cleaved in the case of butyl glycidyl ether whereas the presence of the unsaturated allyl group in the glycidyl ether molecule unexpectedly prefers the scission of the linear ether bond. In both the systems organometallic intermediates are

Zbigniew Grobelny; Andrzej Stolarzewicz; Adalbert Maercker; Stanis?aw Krompiec; Tadeusz Bieg

2002-01-01

180

Photophysical behavior of some aromatic poly(1,3,4-oxadiazole-ether)s derivatives.  

PubMed

The change in electronic absorption and emission spectra of two fluorinated poly(1,3,4-oxadiazole-ether)s in neat and binary solvent mixtures has been studied. The optical properties, absorption and photoluminescence of these polymers were investigated in solution and in solid state. The results were discussed as a function of solvent nature, excitation wavelength and local solvent composition, X2. The Catalan solvent scale was used for describing the solvatochromic shifts of the absorption and emission bands. The following binary solvent mixtures were used: chloroform-N,N'-dimethylformamide (CHCl3-DMF), chloroform-dimethyl sulfoxide (CHCl3-DMSO), and dimethylformamide-dimethyl sulfoxide (DMF-DMSO) and the influence of their composition on the absorption and emission maxima has been analyzed. The preferential solvation parameters such as local mole fraction (X2(L)), excess function (?s2) and preferential solvation constant (KPS) were determined. PMID:24398462

Ipate, A M; Homocianu, M; Hamciuc, C; Airinei, A; Bruma, M

2014-04-01

181

Exogenous Ether Lipids Predominantly Target Mitochondria  

PubMed Central

Ether lipids are ubiquitous constituents of cellular membranes with no discrete cell biological function assigned yet. Using fluorescent polyene-ether lipids we analyzed their intracellular distribution in living cells by microscopy. Mitochondria and the endoplasmic reticulum accumulated high amounts of ether-phosphatidylcholine and ether-phosphatidylethanolamine. Both lipids were specifically labeled using the corresponding lyso-ether lipids, which we established as supreme precursors for lipid tagging. Polyfosine, a fluorescent analogue of the anti-neoplastic ether lipid edelfosine, accumulated to mitochondria and induced morphological changes and cellular apoptosis. These data indicate that edelfosine could exert its pro-apoptotic power by targeting and damaging mitochondria and thereby inducing cellular apoptosis. In general, this study implies an important role of mitochondria in ether lipid metabolism and intracellular ether lipid trafficking. PMID:22348073

Kuerschner, Lars; Richter, Doris; Hannibal-Bach, Hans Kristian; Gaebler, Anne; Shevchenko, Andrej; Ejsing, Christer S.; Thiele, Christoph

2012-01-01

182

Metabolism of Dimethyl Sulphoxide to Dimethyl Sulphone in the Rat and Man  

Microsoft Academic Search

DIMETHYL sulphoxide (DMSO) was first prepared in 1867 (ref. 1), and has been known for some time to be an excellent solvent. However, the first report concerning its metabolic fate in animals appeared only recently, following several papers in which biological and even therapeutic uses for DMSO were suggested2,3. Distefano and Borgstedt4 identified dimethyl sulphide in the expired air of

H. B. Hucker; P. M. Ahmad; E. A. Miller; R. Brobyn

1966-01-01

183

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

SciTech Connect

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

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

2011-02-14

184

Static and Dynamic Transport Studies of Molecular Conductors (DMe-DCNQI) 2Cu  

NASA Astrophysics Data System (ADS)

Pulsed-laser induced transient thermoelectric effect (TTE) and magnetotransport measurements have been made for molecular conductors (DMe-DCNQI)2Cu (h salt) and its deuterated crystals (d7 salt) along the c-axis over the temperature range 4.2 300 K. The photogenerated TTE voltage decays exponentially with two characteristic relaxation times ?1 and ?2 due to hole diffusions, followed by a thermal diffusion process of photogenerated phonons. From these relaxation times, we have estimated the corresponding hole mobilities µ1 and µ2 (especially µ1 at low temperature exceeds as high as 6,000 cm2/Vs), which show an unusually strong temperature dependence at high temperatures (µ1, µ2?T-3 for the h salt and µ2?T-3.5 for the d7 salt), suggesting the presence of any anomalous scattering mechanism in these salts, in addition to conventional neutral impurity and phonon scatterings. Furthermore, with special ohmic contacts to a tiny sample, we have successfully measured the positive Hall voltage and magnetoresistance for the h salt, both of which show a nonlinear magnetic-field dependence. The galvanomagnetic properties of the h salt are reasonably explained by a two-carrier model mainly of two types of holes located around the ? and P points in the Brillouin zone of the three-dimensional (3D) anisotropic band, with concentrations, p? and p P, and mobilities, µ? (=µ2) and µ P (=µ1), respectively. Moreover, we have calculated the temperature dependence of the dc conductivity, in general accord with the observations, whose analyses yield the Fermi energy for the d7 salt, E F = 42 meV (enhancement of E F), compared to 20 meV for the h salt, and the effective mass at the P point [m P = 1.6m0 for the h salt and m P = 2.3m0 for the d7 salt, compared to the theoretical values around the ? point, m?=(3.6 4.3)m0]. The carrier transport along the c-axis at low temperature is mostly due to the holes around the ? point, while, at high temperatures, electrons in the one-dimensional (1D) electron band are also responsible for the carrier transport; the temperature dependence of its conductivity follows the power law ? e ?T-1.9. Finally, we have discussed a possible band model for both salts, where the enhancement of the hole Fermi energy by partial deuteration in the DMe-DCNQI molecule is important to induce the metal-insulator transition occurring in the d7 salt.

Sasaki, Minoru; Tanaka, Shuuji; Negishi, Hiroshi; Inoue, Masasi; Kato, Reizo

1998-05-01

185

Interferometric microscopy observation of the initial stage of electrochemical crystal growth of (DMe-DCNQI) 2Cu  

NASA Astrophysics Data System (ADS)

Interferometric microscopy was used to observe the initial stage of the crystal growth of an organic charge transfer salt (DMe-DCNQI) 2Cu by electrochemical reaction. It was found that concentric patterns started to appear after applying the potential difference between the electrodes. Bright rings of the concentric pattern moved outward for about 15 s and slowed down the movement after the period. It shows the change in the solution concentration just after the nucleation.

Shimada, T.; Kaji, T.; Saiki, K.; Koma, A.

2003-06-01

186

Long-duration Coherent Radio Emission from the dMe Star Proxima Centauri  

NASA Astrophysics Data System (ADS)

The Australia Telescope and Anglo-Australian Telescope were used in May 2000 to record the radio and optical emissions from the dMe flare star Proxima Centauri. Eight bright optical flares over a two-day interval resulted in no detectable excess short-term radio emission at 1.38 and 2.50GHz. However, a slowly declining 1.38GHz emission over the two-day interval was nearly 100% right circular polarised and was restricted to a relatively narrow bandwidth with total intensity (I) and circular polarisation (V) varying significantly over the 104MHz receiver bandwidth. These are the first observations to show that highly-polarised narrowband flare star emission can persist for several days. This signature is attributed to sources of coherent radio emission in the star's corona. Similarities with various solar radio emissions are discussed; however, it is not possible with the existing observations to distinguish between fundamental plasma emission and electron-cyclotron maser emission as the responsible mechanism.

Slee, O. B.; Willes, A. J.; Robinson, R. D.

187

Spectra, Flares, and Mass Loss from the dMe star, Ross 154  

NASA Astrophysics Data System (ADS)

We present results from a Chandra observation of Ross 154, a nearby (2.93 pc) flaring M dwarf (M4.5Ve). During the 57-ksec ACIS-S exposure, a very large flare occurred in which the counting rate increased by over a factor of 100, with an even larger increase in total X-ray power. For the earlier part of the lightcurve, we analyze photon arrival times to determine whether microflaring can explain the quiescent temporal behavior. Following the solar analogy, we assume that flares are distributed as a power-law in energy, and seek to determine whether the power law is steep enough that all coronal emission can be accounted for by flaring activity, as in the case of other active dMe stars such as AD Leo. We also compare elemental abundances derived from the quiescent and flare spectra and place an upper limit on the mass-loss rate by searching for stellar-wind charge-exchange X-ray emission. BW, JD, and DG were supported by the NASA Chandra X-ray Center Guest Observer Program under Grant GO2-3020X during the course of this research. BW, JD, and VK were also supported by NASA contract NAS8-39073 to the CXC.

Wargelin, B. J.; Drake, J. J.; Kashyap, V. L.; Garcia-Alvarez, D.

2004-08-01

188

Measuring exposures to glycol ethers.  

PubMed Central

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

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

1984-01-01

189

Journal of Catalysis 245 (2007) 110123 www.elsevier.com/locate/jcat  

E-print Network

of DME reactions with acetyl groups formed by stoichiometric reactions of acetic anhydride. These studies: Carbonylation; Acid; Zeolite; Mordenite; Dimethyl ether; Methanol; Carbon monoxide; Methyl acetate; Acetic acid; Carboxylic acid 1. Introduction Methanol carbonylation accounts for 60% of acetic acid production worldwide

Iglesia, Enrique

190

21 CFR 524.660a - Dimethyl sulfoxide solution.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 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...

2010-04-01

191

21 CFR 524.660a - Dimethyl sulfoxide solution.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 2011-04-01 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...

2011-04-01

192

21 CFR 524.660 - Dimethyl sulfoxide.  

...HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED...AND TOPICAL DOSAGE FORM NEW ANIMAL DRUGS § 524.660 Dimethyl...per day. Total duration of therapy should not exceed 30 days...per day. Total duration of therapy should not exceed 14...

2014-04-01

193

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

194

Evaluation of poly-ether-ether-ketone (PEEK) for cervical disc replacement devices.  

E-print Network

??Poly-ether-ether-ketone (PEEK) is a high performance aromatic thermoplastic with proven biocompatibility. Recently, it has been proposed as a promising bearing material for cervical total disc… (more)

Xin, Hua

2014-01-01

195

Organic compounds in coal-slurry-pipeline waters. Final report. [Phenol, o-cresol, p-cresol, 2,6-dimethyl phenol, o-ethyl phenol, 3,5-dimethyl phenol  

SciTech Connect

Organic compounds in the water separated from coal pipeline slurry has been investigated on a laboratory basis for the slurry with each of three subbituminous coals: Wyodak, Illinois No. 6 and Black Mesa. The results are compare with results from the Black Mesa Pipeline slurry. Compounds such as aryl hydrocarbons, nitrogenous bases, aryl thiophenes and aryl ethers are all more than 99.9% adsorbed when added to water before slurry formation and are undetectable in the resulting slurry waters. Phenols occur in slurry waters and their identification and quantification using methylation with perdeutero phenol as an internal standard for capillary column GC/MS of the methyl ethers is described. Phenol, o-cresol, p-cresol, 2,6-dimethyl phenol, o-ethyl phenol and 3,5-dimethyl phenol were identified and quantified in all slurry waters from each coal. Laboratory results on slurry waters from Black Mesa coal are in agreement with the results for these phenols in the clariflocculator overflow water at the Mohave Generating Station. 4 figures, 13 tables.

Newton, A.S.; Fox, P.J.; Villarreal, H.; Raval, R.; Walker, W. II

1982-09-01

196

Evidence for spin solitons and their dynamics in a spin-Peierls system (DMe-DCNQI)2Li  

NASA Astrophysics Data System (ADS)

A spin-Peierls system (DMe-DCNQI)2Li has been studied with electron paramagnetic resonance (EPR) under hydrostatic pressure. A definite frequency dependence of the EPR linewidth is observed for the Curie spins that appear below TSP, demonstrating a clear one-dimensional diffusive character similar to t-(CH)x. This is strong evidence for Curie spins to arise from spin solitons as domain walls caused by structural defects. The estimated extent of the spin soliton is less than several molecular units. A relation with the antiferromagnetic ordering provoked by impurities as found in CuGeO3 is discussed.

Hiraoka, Maki; Sakamoto, Hirokazu; Mizoguchi, Kenji; Kato, Reizo

2002-05-01

197

Coupling of alcohols to ethers: The dominance of the surface S{sub N}2 reaction pathway  

SciTech Connect

Coupling of alcohols to ethers, important high value oxygenates, proceeds on acid catalysts via general pathways that uniquely control product composition, oxygen retention, chirality inversion, and kinetics. The dominant pathway is the S{sub N}2 reaction with competition of the alcohols for the surface acid sites. This is exemplified by formation of methyl(ethyl) isobutylether (M(E)IBE) from methanol(ethanol)/isobutanol mixtures, retention of oxygen ({sup 18}O) of the heavier alcohol, and optimum rate as a function of concentration of either reactant alcohol. The S{sub N}2 pathway in the confinement of zeolite pores exhibits additional features of a near-100% selectivity to dimethylether (DME) in H-mordenite and a near-100% selectivity to chiral inversion in 2-pentanol/ethanol coupling to 2-ethoxypentane in HZSM-5. A minor reaction pathway entails olefin or carbenium intermediates, as exemplified by the formation of methyl tertiarybutyl ether (MTBE) from methanol/isobutanol mixtures with oxygen retention of the lighter alcohol. Calculations of transition state and molecular modeling of the oxonium-involving pathways dramatically demonstrate how the reaction path selects the products.

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

1996-12-31

198

Purification of aqueous cellulose ethers  

SciTech Connect

Manufacture of cellulose ethers usually involves high amounts of salt by-products. For application of the product, salt must be removed. In this work, we have studied the injection of high-pressure CO{sub 2} into an aqueous polymer-salt solution; we find that upon addition of isopropanol in addition to CO{sub 2}, the solution separates into two phases. One phase is rich in polymer and water, and the other phase contains mostly isopropanol, water and CO{sub 2}. The salt distributes between the two phases, thereby offering interesting possibilities for development of a new purification process for water-soluble polymers. This work presents experimental phase-equilibrium data for hydroxyethyl cellulose and sodium carboxymethyl cellulose with sodium acetate and potassium sulfate, respectively, in the region 40{degree}C and 30 to 80 bar. Based on these data, we suggest a process for the manufacture and purification of water-soluble cellulose ethers. 15 refs., 14 figs., 9 tabs.

Bartscherer, K.A.; de Pablo, J.J.; Bonnin, M.C.; Prausnitz, J.M.

1990-07-01

199

Polyamideimides Containing Carbonyl And Ether Linkages  

NASA Technical Reports Server (NTRS)

Polyamideimides of new class contain carbonyl and ether connecting groups. New polyamideimides more easily processable, stronger in tension, and more resistant to solvents (including water) than conventional polyamideimides. Improvements in mechanical and chemical properties attributable to semicrystallinity introduced into otherwise amorphous polymers by incorporation of carbonyl and ether linkages.

Hergenrother, Paul M.; Havens, Stephen J.

1994-01-01

200

Research on Si-Al based catalysts prepared by complete liquid-phase method for DME synthesis in a slurry reactor  

NASA Astrophysics Data System (ADS)

A series of Si-Al based DME synthesis catalysts were prepared by complete liquid-phase method and characterized by in situ XPS, XRD, N 2 adsorption and NH 3-TPD analyses. Based on the results, the addition of Si could adjust the pore structure and surface acidity of catalyst, exhibiting a strong promoting effect on the CO conversion and DME selectivity. However, when Si/Al ratio is higher, Si would cover active sites and increase the amount of strong acidity sites, causing the reduction in catalytic activity. It was found from in situ XPS characterization that Cu 0 is the active center of methanol synthesis in DME production, and the addition of Si changes the chemical surroundings of active components and weaken the interaction between Cu, Zn and Al, which maybe give rise to the decrease in catalyst stability.

Li, Zhihong; Zuo, Zhijun; Huang, Wei; Xie, Kechang

2011-01-01

201

From Radio to X-Ray: Flares on the dMe Flare Star EV Lacertae  

NASA Astrophysics Data System (ADS)

We present the results of a campaign to observe flares on the M dwarf flare star EV Lacertae over the course of two days in 2001 September, utilizing a combination of radio continuum, optical photometric and spectroscopic, ultraviolet spectroscopic, and X-ray spectroscopic observations to characterize the multiwavelength nature of flares from this active, single, late-type star. We find flares in every wavelength region in which we observed. A large radio flare from the star was observed at both 3.6 and 6 cm and is the most luminous example of a gyrosynchrotron flare yet observed on a dMe flare star. The radio flare can be explained as encompassing a large magnetic volume, comparable to the stellar disk, and involving trapped electrons that decay over timescales of hours. Flux enhancements at 6 cm accompanied by highly negatively circularly polarized emission (?c-->-100%) imply that a coherent emission mechanism is operating in the corona of EV Lac. There are numerous optical white-light flares, and yet no signature of emission-line response from the chromosphere appears. Two small ultraviolet enhancements differ in the amount of nonthermal broadening present. There are numerous X-ray flares occurring throughout the observation, and an analysis of undispersed photons and grating events reveals no evidence for abundance variations. Higher temperatures are present during some flares; however, the maximum temperature achieved varies from flare to flare. There is no evidence for density variations during any flare intervals. In the multiwavelength context, the start of the intense radio flare is coincident with an impulsive optical U-band flare, to within 1 minute, and yet there is no signature of an X-ray response. There are other intervals of time when optical flaring and UV flaring is occurring, but these cannot be related to the contemporaneous X-ray flaring: the time-integrated luminosities do not match the instantaneous X-ray flare luminosity, as one would expect for the Neupert effect. We investigate the probability of chance occurrences of flares from disparate wavelength regions producing temporal coincidences but find that not all the flare associations can be explained by a superposition of flares due to a high flaring rate. We caution against making causal associations of multiwavelength flares based solely on temporal correlations for high flaring rate stars such as EV Lac.

Osten, Rachel A.; Hawley, Suzanne L.; Allred, Joel C.; Johns-Krull, Christopher M.; Roark, Christine

2005-03-01

202

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

203

Quasi-one-dimensional diffusive motion of spin solitons in the spin-Peierls state of (DMe-DCNQI) 2Li  

NASA Astrophysics Data System (ADS)

(DMe-DCNQI) 2Li is a {1}/{4} filled spin-Peierls (SP) system with the SP transition temperature T sp?65 K. Using frequency variable ESR at temperatures enough below Tsp, the existence of spin solitons which could arise from domains with finite chain length, is demonstrated. It is also found that Tsp is enhanced by hydrostatic pressure and can be reproduced well with Cross-Fisher's relation. Within our knowledge, this is the first example of such good consistency with theory in pressure dependence of Tsp. This is probably due to a high one dimensionality of the electronic structure in (DMe-DCNQI) 2Li, even under high pressures.

Hiraoka, Maki; Sakamoto, Hirokazu; Mizoguchi, Kenji; Kato, Reizo

2003-05-01

204

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

NASA Technical Reports Server (NTRS)

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

Bopp, B. W.; Espenak, F.

1977-01-01

205

Phillips ready to license process for production of fuel ethers  

SciTech Connect

Phillips Petroleum Co. is poised to license its high conversion process to produce fuel ethers for blending in reformulated gasolines. The technology has been proven in a Phillips semiworks at Bartlesville, Okla. The process can produce methyl tertiary butyl ether, ethyl tertiary butyl ether, tertiary amyl methyl ether, or tertiary amyl ethyl ether with typical refinery process equipment and techniques. Phillips said it can achieve conversion levels of 92-99%, depending on the ether. The ether produced is determined by which hydrocarbon fraction is used for feedstock and which alcohol is chosen for reaction. The process is described.

Not Available

1993-04-19

206

Dimethyl-ammonium dichloridotriphenyl-stannate(IV)  

PubMed Central

The title salt, [(CH3)2NH2][Sn(C6H5)3Cl2], was obtained as a by-product of the reaction between bis­(dimethyl­ammonium) oxalate and triphenyl­tin chloride. In the stannate anion, the trigonal–bipyramidal coordination environment of the SnIV atom is defined by the phenyl groups in equatorial and the Cl atoms in axial positions. The cations are connected to adjacent anions through N—H?Cl and C—H?Cl hydrogen-bonding inter­actions, leading to a chain motif parallel to [100]. PMID:22807710

Sow, Yaya; Diop, Libasse; Kociok-Kohn, Gabriele; Molloy, Kieran C.

2012-01-01

207

Biogenic production of dimethyl sulfide: Krill grazing  

SciTech Connect

Dimethyl sulfide (DMS), a dominant sulfur compound in sea water, is a possible precursor for cloud condensation nuclei in the atmosphere and may influence global climate. The primary source of DMS is phytoplankton, but the mechanisms remain uncertain, and concentrations of DMS in the ocean vary spatially and temporally. Laboratory studies suggest zooplankton grazing may be an important process leading to the formation of DMS in the ocean. This paper describes ocean studies which examine the suggestion that grazing by krill may be a significant source for DMS production in the antarctic coastal region. 11 refs., 2 figs.

Daly, K.L.; DiTullio, G.R. (Univ. of Tennessee, Knoxville, TN (United States))

1993-01-01

208

21 CFR 868.5420 - Ether hook.  

Code of Federal Regulations, 2010 CFR

...Identification. An ether hook is a device that fits inside a patient's mouth and that is intended to...represented as sterile, it is exempt from the current good manufacturing practice requirements of the quality system regulation in...

2010-04-01

209

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

Code of Federal Regulations, 2013 CFR

...bis(fattyalkyl) dimethyl, salts with tannins (generic...bis(fattyalkyl) dimethyl, salts with tannins (generic...bis(fattyalkyl) dimethyl, salts with tannins (PMN P-12-437...j). (ii) Release to water. Requirements as...

2013-07-01

210

Theoretical Study on the Dark Oxidation Reaction Mechanism of Ethers  

Microsoft Academic Search

The dark oxidation reactions of ethers including aether, isopropyl ether, phenyl isopropyl ether, and benzyl isopropyl ether have been studied by using density functional theory calculations. The structures of initial contact charge transfer complexes (CCTCs), transition states and caged radical intermediates have been located at the B3LYP\\/6-31G (d) level. The bonding nature of ethers with triplet O2 in CCTCs has

WANG Gui-Xiu; ZHU Rong-Xiu; LIU Cheng-Bu

211

Poly(aryl ethers) and related polysiloxane copolymer molecular coatings: Preparation and radiation degradation  

NASA Technical Reports Server (NTRS)

The radiation degradation of poly(arylene ether sulfones) and related materials is studied. These basic studies are important both as a means to developing stronger, more stable matrix resins for composite materials, as well as to improve the data base in regard to chemical structure-physical property relationships. Thirty homo and copolymers were synthesized, at least partially characterized and, in several cases suitable film casting techniques were developed. Four samples were chosen for initial radiation degradation. Poly(dimethyl siloxane) soft bocks/segments can preferentially migrate to the surface of copolymer films. Since siloxanes are utilized as thermal control coatings, this form of 'molecular' coating is of interest. The chemistry for preparing such copolymers with any of the polymers described was demonstrated.

Mcgrath, J. E.

1982-01-01

212

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

NASA Astrophysics Data System (ADS)

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

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

213

Catalytic kinetic determination of ultratrace amounts of nitrite with detection by linear scan voltammetry at a DME.  

PubMed

Nitrite has a very strong catalytic effect on the bromate oxidation of Methyl Orange in dilute sulphuric acid medium. The oxidation product of methyl orange exhibits a well derivative voltammetric wave at -0.41 V vs. SCE in sodium hydroxide medium. The linear scan voltammetric behaviour for the product at a DME has been studied, and it was selected as indicator component for the indicator reaction. Based on these studies, a novel and highly sensitive and selective catalytic reaction-voltammetric method for nitrite is proposed. A detection limit of 2 x 10(-9)M and calibration graph from 4 x 10(-7) to 4 x 10(-7)M nitrite are obtained. Nitrite in water samples was determined by this method, with satisfactory results. PMID:18965522

Zhi-Liang, J; Hai-Cuo, Q; Da-Qiang, W

1992-10-01

214

Schottky Specific Heat due to the Tunneling Rotation of Methyl Groups in Deuterated (DMe-DCNQI)2Cu System  

NASA Astrophysics Data System (ADS)

In the course of studies on thermal properties of (DMe-DCNQI)2Cu systems that exhibit a reentrant metal-insulator transition, we discovered a Schottky type of specific heat with a peak around 8 K. The peak value exceeds 25 J/mol\\cdotK. This type of anomaly is observed only on samples composed of molecules containing partially deuterated methyl groups, and was found to be originated from the rotation of deuterated methyl groups that occurs by quantum tunneling. From an analysis of the specific heat curve, we obtained information concerning the low lying energy level scheme of deuterated methyl group CH2D. It has a non-degenerated ground state and doubly degenerated first excited states located about 20 K above the ground state.

Nishio, Yutaka; Mori, Yuko; Sasaki, Sachie; Kajita, Koji; Aonuma, Shuji; Sawa, Hiroshi; Tamura, Masafumi; Kato, Reizo

2002-07-01

215

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

Code of Federal Regulations, 2010 CFR

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

2010-04-01

216

13C NMR study of the metal-insulator transition in (DMe-DCNQI)2Cu systems with partial deuteration  

NASA Astrophysics Data System (ADS)

The electronic states of a series of (DMe-DCNQI)2Cu systems with nondeuterated and partially deuterated methyl groups in a DMe-DCNQI molecule have been investigated by 13C NMR measurements at the cyano carbon sites. The Knight shift of the nondeuterated specimen, which is metallic in the whole temperature range, is not scaled to the total spin susceptibility, demonstrating that the metallic state has several electronic bands with different local spin susceptibility due to the ?-d hybridization. In the insulating phases of the partially deuterated specimens, 13C NMR spectra are split into two lines, one of which has a nearly zero shift and the other has a large positive shift with the Curie-Weiss temperature dependence. The former line comes from the cyano group coordinated to the nonmagnetic Cu+ ion, while the latter comes from the cyano group coordinated to the magnetic Cu2+ ion. The sign of the shift and intensity analysis provide an evidence that, in the insulating phase, spin is localized exclusively at one-third of the Cu sites without any population on the DCNQI molecule. This is considered as a manifestation of strong electron correlation in the Cu sites. The low-temperature reentrant metallic state in the partially deuterated system is found to be just the same as the stable metallic state in the nondeuterated system through the shift and relaxation rate behaviors. No fluctuations are observed in the vicinity of the metal-insulator and insulator-metal reentrant transitions, showing that the transitions are of the first order.

Kawamoto, A.; Miyagawa, K.; Kanoda, K.

1998-07-01

217

Synthesis and Modification of Poly(ether ether ketone) and their Properties: A Review  

Microsoft Academic Search

Synthetic aromatic polyarylether ketones are known for their high performance applications. Poly(ether ether ketone) is an important material which is most widely used in such aggressive environments as nuclear plants, oil and geothermal wells, chemical plants, and high-pressure steam valves. Considering the wide range of properties of PEEK polymers, a variety of structurally modified PEEK polymers are also reported. This

Devesh Shukla; Yuvraj Singh Negi; Jugmendra Sen Uppadhyaya; Vijai Kumar

2012-01-01

218

Chemoselective and direct functionalization of methyl benzyl ethers and unsymmetrical dibenzyl ethers by using iron trichloride.  

PubMed

Methyl and benzyl ethers are widely utilized as protected alcohols due to their chemical stability, such as the low reactivity of the methoxy and benzyloxy groups as leaving groups under nucleophilic conditions. We have established the direct azidation of chemically stable methyl and benzyl ethers derived from secondary and tertiary benzyl alcohols. The present azidation chemoselectively proceeds at the secondary or tertiary benzylic positions of methyl benzyl ethers or unsymmetrical dibenzyl ethers and is also applicable to direct allylation, alkynylation, and cyanation reactions, as well as the azidation. The present methodologies provide not only a novel chemoselectivity but also the advantage of shortened synthetic steps, due to the direct process without the deprotection of the methyl and benzyl ethers. PMID:24459116

Sawama, Yoshinari; Goto, Ryota; Nagata, Saori; Shishido, Yuko; Monguchi, Yasunari; Sajiki, Hironao

2014-02-24

219

Vibrational spectra and structure of dimethyl oxalate and dimethyl oxalate-d6  

NASA Technical Reports Server (NTRS)

The vibrational spectra of dimethyl oxalate-d6 have been examined in connection with a re-examination of the spectra and structure of dimethyl oxalate. The vibrational spectra of the compound had previously been interpreted as being consistent with a trans C2h structure in the solid phase and a non-planar C2 form in the liquid and gas phases. This behavior is not consistent with that observed in similar compounds and a re-evaluation of the facts suggests that the major spectral changes which are observed may be caused by destroying an intermolecular association in going from the solid to the liquid phase, which allows the methyl groups to assume positions out of the plane. Some modifications and additions have been made in the vibrational assignment and assignments are presented for the deuterated compound.

Durig, J. R.; Brown, S. C.

1976-01-01

220

Catalytic oxidiative decomposition of dimethyl methylphosphonate over Cu-substituted hydroxyapatite  

SciTech Connect

The oxidative decomposition of dimethyl methylphosphonate (DMMP) has been studied over Cu-substituted hydroxyapatite catalysts in a flow reactor in the temperature range 373-773 K. by substitution of a portion of the Ca[sup 2+] by Cu[sup 2+] in the hydroxyapatite lattice, the catalytic activity was markedly increased. The composition Cu[sub 2]Ca[sub 8](PO[sub 4])[sub 6](OH)[sub 2], herein called Cu2-HA, had the highest activity among these catalysts. All the catalysts showed 100% conversion at the beginning of the reaction, but became deactivated after a period of time. Only CO[sub 2] and H[sub 2]O were produced during the [open quotes]protection period[close quotes] of the 100% conversion. With deactivation, CO[sub 2] formation decreased and methanol and dimethyl ether appeared as products. A phosphorus-containing product was not detected in the gas phase. Some condensate of phosphoric acid appeared in the outlet of the reactor after deactivation. Several analytical methods revealed that carbonaceous compounds did not remain on the surface after 773-K oxidative regeneration, but the phosphorus compounds that had accumulated during the reaction were; not eliminated. The catalytic activity of Cu-substituted hydroxyapatite was compared to that of conventional supported Pt catalysts. This study suggested that easily made and cheap Cu-substituted hydroxyapatite catalysts could be used as successful alternatives to conventional adsorbents and catalytic systems based on supported noble metals devised for protection against nerve gases in warfare. 35 refs., 10 figs., 2 tabs.

Lee, Kwan Young (Univ. of Tokyo (Japan)); Houalla, M.; Hercules, D.M.; Hall, W.K. (Univ. of Pittsburgh, PA (United States))

1994-01-01

221

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

PubMed Central

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

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

2012-01-01

222

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

PubMed

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

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

2009-12-14

223

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

224

Phthalocrowns: isoindoline-crown ether macrocycles.  

PubMed

The reaction of diiminoisoindoline with amine-terminated polyethers results in the formation of phthalocrown macrocycles. For n = 1 (where n is the number of ether units), a 2 + 2 condensation takes place, but for n = 2 and 3, a 1 + 1 macrocycle formation occurs. The n = 2 phthalocrown is particularly stable due to a strong intramolecular hydrogen bond, but the n = 3 ring hydrolyzes to form a 3-imino-1-oxoisoindoline derivatized crown ether species. For the n = 1 phthalocrown, we observed dynamic behavior in the (1)H NMR spectrum, and using VTNMR were able to measure a ?G(‡) = 44.6 kJ/mol for proton exchange. PMID:23186271

Tamgho, Ingrid-Suzy; Engle, James T; Ziegler, Christopher J

2012-12-21

225

40 CFR 721.3500 - Perhalo alkoxy ether.  

Code of Federal Regulations, 2011 CFR

...2011-07-01 false Perhalo alkoxy ether. 721.3500 Section 721.3500 Protection of Environment ENVIRONMENTAL PROTECTION...New Uses for Specific Chemical Substances § 721.3500 Perhalo alkoxy ether. (a) Chemical...

2011-07-01

226

40 CFR 721.3500 - Perhalo alkoxy ether.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 false Perhalo alkoxy ether. 721.3500 Section 721.3500 Protection of Environment ENVIRONMENTAL PROTECTION...New Uses for Specific Chemical Substances § 721.3500 Perhalo alkoxy ether. (a) Chemical...

2010-07-01

227

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

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

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

228

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

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

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

229

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

Microsoft Academic Search

We have synthesized and fully characterized a tetrakis(ethane-1,2-dithiolato)uranate(IV), (Li(dme))â(U(edt)â) (1), the first homoleptic dithiolate complex of an f element. The complex crystallizes with an additional DME solvent molecule, and its structure was determined by an x-ray study. The coordination geometry about the uranium center is dodecahedral, and four lithium cations surround the (U(edt)â)⁴⁻ anion. Each lithium bridges two sulfur atoms

Kazuyuki Tatsumi; Ichiro Matsubara; Yoshihisa Inoue; Akira Nakamura; R. E. Cramer; G. J. Tagoshi; J. A. Golen; J. W. Gilje

1990-01-01

230

Mass spectral identification of the metabolites of alpha,alpha-dimethyl-4-(alpha,alpha,beta,beta-tetrafluorophenethyl)-benzylamine (MK-251), a novel antiarrhythmic agent, in various species.  

PubMed

The identification of a number of metabolites of the novel antiarrhythmic agent, alpha,alpha-dimethyl-4-(alpha,alpha,beta,beta-tetrafluorophenethyl)benzylamine (MK-251), is presented. The compound is extensively metabolized by dog, monkey, baboon and man. Similar metabolic profiles were obtained for all species. Isolation and purification were accomplished by solvent extraction and chromatographic (column, gas and thin-layer) procedures. Gas chromatography, derivatization, infrared, nuclear magnetic resonance and particularly combined gas chromatography low and high resolution mass spectrometry techniques were employed to characterize the metabolites. The major urinary and plasma metabolites were identified as 2-[4-(alpha,alpha,beta,beta-tetrafluorophenethyl)phenyl]-2-propanol and its glucuronide conjugate. Other metabolites characterized were: the N-glucuronide of MK-251; 2-[4-(alpha,alpha,beta,beta-tetrafluorophenethyl)phenyl]propene; 2-nitro-2-[4-)alpha,alpha,beta,beta-tetrafluorophenethyl)phenyl]propane; alpha,alpha-dimethyl-4(alpha,alpha,beta,beta-tetrafluorophenethyl)benzyl methyl ether; and 4-(alpha,alpha,beta,beta-tetrafluorophenethyl)acetophenone. The 0-methyl ether metabolite represents the first instance of in vivo alkylation of a tertiary alcohol. Tentative identification was made for the N-hydroxy analog of MK-251 and for the glycol analog of 2-[4-(alpha,alpha,beta,beta-tetrafluorophenethyl)phenyl]-2-propanol. The observed pharmacological response appears to result mainly from MK-251 and not from the four metabolites. PMID:826289

Zacchei, A G; Rhodes, R E; Christy, M E

1976-12-01

231

Synthesis and transformations of vinyl ethers of ethanolamines  

Microsoft Academic Search

1.A study was made of the polymerization of some vinyl ethers of ethanolamines in presence of ionogenic and free-radical catalysts.2.Vinyl ethers of ethanolamines are less reactive in ionic polymerization than unsubstituted alkyl vinyl ethers, and they tend to undergo radical polymerization under the initiation of azodiisobutyronitrile.3.The relation of the structure of the ethanolamine vinyl ether to its tendency to polymerize

I. A. Chekulaeva; I. V. Lipovich; M. F. Shostakovskii

1963-01-01

232

21 CFR 73.37 - Astaxanthin dimethyl-disuccinate.  

Code of Federal Regulations, 2013 CFR

...Section 73.37 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT...ADDITIVES EXEMPT FROM CERTIFICATION Foods § 73.37 Astaxanthin dimethyl-disuccinate...use in color additive mixtures for coloring foods. (b) Specifications...

2013-04-01

233

21 CFR 73.37 - Astaxanthin dimethyl-disuccinate.  

Code of Federal Regulations, 2012 CFR

...Section 73.37 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT...ADDITIVES EXEMPT FROM CERTIFICATION Foods § 73.37 Astaxanthin dimethyl-disuccinate...use in color additive mixtures for coloring foods. (b) Specifications...

2012-04-01

234

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

Code of Federal Regulations, 2011 CFR

...false Ether amine phosphonate salt (generic). 721.10067...10067 Ether amine phosphonate salt (generic). (a) Chemical...generically as ether amine phosphonate salt (PMNs P-05-57, P-05-58...uses are: (i) Release to water . Requirements as...

2011-07-01

235

40 CFR 721.3430 - 4-Bromophenyl phenyl ether.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 false 4-Bromophenyl phenyl ether. 721.3430 Section 721.3430...Substances § 721.3430 4-Bromophenyl phenyl ether. (a) Chemical substance and...The chemical substance 4-bromophenyl phenyl ether (CAS No. 101-55-3)...

2010-07-01

236

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

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

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

237

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

238

Metal ion complexation by ionizable crown ethers  

SciTech Connect

During the report period a variety of new lipophilic ionizable crown ethers with pendent proton-ionizable groups has been synthesized. In addition a series of proton-ionizable crown ethers without lipophilic groups was prepared to study how structural variations within the ligand influence metal ion complexation in homogeneous media as assessed by NMR spectroscopy or titration calorimetry. A third class of new metal ion-complexing agents is a series of lipophilic acyclic polyether dicarboxylic acids. Competitive solvent extractions of alkali metal and alkaline earth cations and of the mixed species have been conducted to reveal the influence of ring size, nature and attachment site of the lipophilic group, sidearm length, and proton-ionizable group identity and location upon the selectivity and efficiency of metal ion complexation. In addition to such studies of structural variation within the lipophilic proton-ionizable crown ether, the effect of changing the organic solvent and variation of the stripping conditions have been assessed. The ability of proton- ionizable crown ethers to function as selective metal ion carriers in liquid membrane transport processes has been examined in both bulk liquid membrane and polymer-supported liquid membrane transport systems. New acyclic and cyclic polyether carboxylic acid resins have been prepared by condensation polymerization and characterized.

Bartsch, R.A.

1990-06-01

239

Imide/arylene ether block copolymers  

NASA Technical Reports Server (NTRS)

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

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

1991-01-01

240

Polybrominated diphenyl ether (PBDE) flame retardants  

Microsoft Academic Search

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

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

2001-01-01

241

Distribution of ether in two postmortem cases.  

PubMed

Diethyl ether (ether) is a volatile liquid that was used in the 1800s as an anesthetic agent; however, it is no longer used for this purpose, partly because of its odor and flammability. Two postmortem cases in which ether was detected are presented. The first case was an 18-year-old male found hanging from a basement ceiling brace in a semi-sitting position with a gas mask covering his face. A container of Prestone starting fluid and a bong were found on the floor close to the body. The second case was a 20-year-old male found unresponsive in his dormitory room with two black plastic trash bags secured over his head. Two saturated rags and a resealable bag containing a clear liquid were contained within these trash bags. An almost empty can of Tradco starting fluid was also found at the scene. Ether concentrations were determined by headspace gas chromatography-mass spectrometry in the selective ion monitoring mode. In case #1, the medical examiner ruled that the cause of death was asphyxia due to hanging; the manner of death was undetermined. In case #2, the medical examiner ruled that the cause of death was asphyxia and the manner of death was suicide. PMID:17132265

Cox, Dawn; DeRienz, Rebecca; Jufer Phipps, Rebecca A; Levine, Barry; Jacobs, Aaron; Fowler, David

2006-10-01

242

POLYBROMINATED DIPHENYL ETHERS IN SOUTHERN MISSISSIPPI CATFISH  

EPA Science Inventory

Polybrominated diphenyl ethers (PBDEs) are used as flame retardants in a wide variety of consumer products. Concerns surrounding these compounds are primarily due do their ubiquitous presence in the environment as well as in human tissue, such as milk, coupled with evidence indi...

243

Exposure of Americans to polybrominated diphenyl ethers  

Microsoft Academic Search

Polybrominated diphenyl ethers, PBDEs, are a class of brominated flame retardants that, like other persistent organic pollutants (POPs), have been found in humans, wildlife, and biota worldwide. Unlike other POPs, however, the key routes of human exposure are not thought to be food and fish, but rather are from their use in household consumer products, and to the high levels

Matthew Lorber

2008-01-01

244

IGNITION IMPROVEMENT OF LEAN NATURAL GAS MIXTURES  

SciTech Connect

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

Jason M. Keith

2005-02-01

245

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

Microsoft Academic Search

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

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

1998-01-01

246

On the cumulative fatigue damage in short carbon fiber reinforced poly-ether-ether-ketone  

Microsoft Academic Search

The actual load for mechanical structures is not always a constant stress amplitude. Therefore, in order to predict the fatigue life under various stress amplitudes, it is important to investigate whether Miner's rule is applicable or not. In this paper, rotating-bending fatigue tests under two-step loading for short carbon fiber reinforced poly-ether-ether-ketone, CFRPEEK, were carried out in order to investigate

Hiroshi Noguchi; Yun-Hae Kim; Hironobu Nisitani

1995-01-01

247

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

248

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

249

Bifunctional pathways mediated by Pt clusters and Al2O3 in the catalytic combustion of dimethyl ether{  

E-print Network

turnover rates than on the individual components or on Pt clusters supported on non-acidic oxides A parallel study of the effects of Pt cluster dispersion (0.02­0.99 dispersion) detected significant effects., Lot# C1643) and SiO2 (Chromatographic Silica Media, CAS# 112926- 00-8) in flowing dry air at 923 K

Iglesia, Enrique

250

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...

251

Certain glycol ethers eliminated from toxic chemical release reporting requirements  

SciTech Connect

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

NONE

1994-09-01

252

Polyrotaxanes by in situ self threading during polymerization of functional macrocycles. Part 2: Poly(ester crown ether)s  

Microsoft Academic Search

Poly(ester crown ether)s were synthesized by direct condensation of bis(5-carboxy-m-phenylene)-(3x + 2)-crown-x, x = 6,8 and 10 (1a, 1b and 1c) with bisphenols via the Higashi method. The formation of higher molecular weight poly(ester crown ether) 5 from the 32-membered crown ether 1c and bisphenol-A (2a) as compared to polyester 3 from 20-membered crown ether 1a and bisphenol-A, polyester 4

Harry W Gibson; Devdatt S Nagvekar; Jason Powell; Caiguo Gong; William S Bryant

1997-01-01

253

Synthesis and utility of fluorogenic acetoxymethyl ethers.  

PubMed

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

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

2011-01-01

254

Synthesis and utility of fluorogenic acetoxymethyl ethers†  

PubMed Central

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

Lavis, Luke D.; Chao, Tzu-Yuan

2011-01-01

255

Densitometric quantification of ether-type phospholipids.  

PubMed

A quantification method for analysis of individual ether-type phospholipids is important in studies of the regulation of membrane lipid biosynthesis in Archaea. For ester-type lipid of Bacteria and Eucarya, a densitometric method has been established for simultaneous quantification of individual phospholipids visualized with molybdenum blue reagent on a TLC plate. In this study, we developed a TLC densitometric method for rapid quantitative determination of 6 kinds of main ether-type phospholipids in a methanogenic archaeon and an extremely halophilic archaeon. It has been reported previously that on densitometric quantification the values of molar absorptivities are approximately the same among most ester-type phospholipids. On the other hand, we found significant disparity in the molar absorptivity of archaeal ether-type lipids and serine-containing ester-type lipid. Therefore, analysis should be accomplished by use of each standard mixture. Compared with a previous method (preparative TLC method) that is measurement of inorganic phosphate of silica gel powder scraped off from spots of phospholipids on a TLC plate, the TLC densitometry is accomplished at one tenth the sample size in a short time. PMID:18783009

Oe, Shinji; Tanaka, Takahiro; Ohga, Mami; Koga, Yosuke; Morii, Hiroyuki

2008-09-01

256

40 CFR 721.1225 - Benzene, 1,2-dimethyl-, poly-propene derivatives, sulfonated, po-tas-sium salts.  

Code of Federal Regulations, 2013 CFR

...1,2-dimethyl-, poly-propene derivatives, sulfonated, po-tas-sium salts...1,2-dimethyl-, poly-propene derivatives, sulfonated, po-tas-sium salts...benzene, 1,2-dimethyl-, polypropene derivatives, sulfonated, potassium salts...

2013-07-01

257

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

258

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

259

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

260

Synthesis and characteristics of polyarylene ether sulfones  

NASA Technical Reports Server (NTRS)

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

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

1981-01-01

261

Stellar model chromospheres. XII - High-resolution, absolute flux profiles of the CA II H and K lines in dMe and non-dMe stars  

NASA Astrophysics Data System (ADS)

We present 142 mÅ resolution spectra of the cores and wings of the Ca II H and K lines in three dMe and four comparison dwarf M stars, obtained with the KPNO 4 m echelle spectrograph and blue image tube. The narrow-band photometry of Willstrop and the Barnes and Evans relations for stellar angular diameters convert the observed relative flux to absolute surface flux units with an estimated uncertainty of ± 15 %. We derive chromospheric radiative loss rates in the H and K lines and discuss trends in these loss rates with effective temperature. Monochromatic surface fluxes are tabulated for different features in the H and K lines, and radiation temperatures are derived from the mean surface fluxes at K1 and H1, respectively. We find TR(H1) > TR(K1), consistent with partial redistribution theory. The TR(K1)/Teff ratio is higher in these M dwarfs than the giants studied in Paper X, and it is anomalously high for the dMe flare star YZ CMi. If TR(K1)/Teff is an empirical age indicator, then the result for YZ CMi implies that flare activity and youth are directly correlated, as has been suggested by other investigators. Moreover, the result implies that a high degree of nonradiative heating is present in the upper photospheres of dMe stars. Measurements of line widths at H1 and K1 are presented together with FWHM data for the H and K lines. We find that the scaling law proposed by Ayres generally agrees with the observed trend exhibited by the K1 widths. We also discuss chromospheric radiative loss rates in the H? line compared with loss rates in the H and K lines, and present corrected FWHM(K) widths and compare them to the widths predicted by the Wilson-Bappu relation as calibrated by Lutz.

Giampapa, M. S.; Worden, S. P.; Schneeberger, T. J.; Cram, L. E.

1981-06-01

262

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

263

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

Code of Federal Regulations, 2011 CFR

...Fluocinolone acetonide, dimethyl sulfoxide otic solution. 524.981e Section 524.981e ...Fluocinolone acetonide, dimethyl sulfoxide otic solution. (a) Specifications. Each milliliter of solution contains 0.01 percent of...

2011-04-01

264

21 CFR 524.981d - Fluocinolone acetonide, dimethyl sulfoxide solution.  

Code of Federal Regulations, 2011 CFR

...Fluocinolone acetonide, dimethyl sulfoxide solution. 524.981d Section 524.981d ...Fluocinolone acetonide, dimethyl sulfoxide solution. (a) Specifications. Each milliliter of solution contains 0.01 percent...

2011-04-01

265

Thermal conductivity of (DMe-DCNQI)2Li1-xCux (0?x?0.14) : Phonon propagation and the spin-Peierls lattice distortion  

NASA Astrophysics Data System (ADS)

We have measured the thermal conductivity of organic molecular crystals (DMe-DCNQI)2Li1-xCux (0?x?0.14) over a wide temperature range between 4 and 250K . We observed the phonon contribution in the whole range measured. A phonon peak was observed near ˜20K . This peak denotes a crossover between the phonon mean free path that diverges as T-2 and the phonon specific heat that decreases as T3 . The peak height decreases with the reduction of Cu concentration x and vanishes in the x=0 sample. We discuss this behavior in terms of the spin-Peierls local lattice distortion.

Torizuka, Kiyoshi; Tajima, Hiroyuki; Yamamoto, Takashi

2005-05-01

266

Spin soliton dynamics and pressure effects in the spin-Peierls system (DMe-DCNQI) 2M (M=Li, Ag)  

NASA Astrophysics Data System (ADS)

(DMe-DCNQI) 2M (M=Li, Ag) is a {1}/{4}-filled spin-Peierls system. We study the spin/charge dynamics in the insulating state by EPR. The linewidth shows exponential dependence at T? Tsp. Further, pressure enhances mainly prefactor of the exponential dependences. These results are successfully understood in terms of the relaxation accompanied with the intercolumn hopping caused by the spin-orbit interaction both for the Li and Ag salts. This is consistent with the scenario that the hole and spin solitons help the intercolumn charge and spin transports.

Hiraoka, M.; Sakamoto, H.; Mizoguchi, K.; Kato, T.; Furukawa, K.; Kato, R.; Hiraki, K.; Takahashi, T.

2004-05-01

267

Charge Transport in the Insulating State of (DMe-DCNQI)2Li above TSP: A Possible Fractional Charge Soliton Conduction with ±1/2e  

NASA Astrophysics Data System (ADS)

A spin-Peierls system (DMe-DCNQI)2Li is studied with W-band electron paramagnetic resonance (EPR) (?94 GHz) to unveil a charge transport mechanism in the insulating 4kF charge density wave state above TSP. The electron hopping between the neighbor DCNQI columns provides an additional broadening of the EPR linewidth, since the neighbor columns are generally nonequivalent to each other with respect to g shift. The obtained intercolumn hopping rates lead us to the conclusion that the electron hopping to a hole soliton carrying a fractional charge of e/2 in the neighbor column dominates the intercolumn charge transport.

Hiraoka, Maki; Sakamoto, Hirokazu; Mizoguchi, Kenji; Kato, Tatsuhisa; Kato, Reizo

2003-08-01

268

Alcohol dehydration: Mechanism of ether formation using an alumina catalyst  

SciTech Connect

Ether formation during the dehydration of secondary alcohols, namely, 2-butanol, 3-pentanol, and 1-cyclopentylethanol, was investigated. Using the proper reaction conditions, the yield of di-2-butyl ether during the dehydration of 2-butanol on alumina can be as high as 40%. That ether is formed by adding an alcohol to the alkene is ruled out by the results from deuterium tracer studies. Results from experiments using S(+)- 2-butanol suggest that the formation of di-2-butyl ether occurs by a S{sub N}2-type mechanism. 33 refs., 5 figs., 3 tabs.

Shi, B.; Davis, B.H. [Univ. of Kentucky, Lexington, KY (United States)] [Univ. of Kentucky, Lexington, KY (United States)

1995-12-01

269

Synthesis and photopolymerization of propenyl ether and epoxy functionalized siloxanes  

NASA Astrophysics Data System (ADS)

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

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

2003-01-01

270

(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 PMID:23468713

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

2012-01-01

271

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

PubMed

In the title compound, [CdI2(C12H12N2)(C3H7NO)], the Cd(II) 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 dimethyl-formamide ligand and two I(-) anions. ?-? stacking between pyridine rings of adjacent mol-ecules [centroid-centroid distance = 3.666?(3) and 3.709?(4)?Å] stabilizes the three-dimensional structure. PMID:23468713

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

2012-12-01

272

(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. PMID:21579009

Kalateh, Khadijeh; Ahmadi, Roya; Amani, Vahid

2010-01-01

273

Adsorption of dimethyl sulfide from aqueous solution by a cost-effective bamboo charcoal  

Microsoft Academic Search

The adsorption of dimethyl sulfide from an aqueous solution by a cost-effective bamboo charcoal from Dendrocalamus was studied in comparison with other carbon adsorbents. The bamboo charcoal exhibited superior adsorption on dimethyl sulfide compared with powdered activated carbons at different adsorbent dosages. The adsorption characteristics of dimethyl sulfide onto bamboo charcoal were investigated under varying experimental conditions such as particle

Ming Wang; Zheng-Hong Huang; Guangjia Liu; Feiyu Kang

2011-01-01

274

Synthesis of (2,4-dimethyl-3-carbethoxy-5-pyrrolyl) succinic acid and its derivatives  

Microsoft Academic Search

a-Pyrrolylsuccinic and (2,4-dimethyl-3-carbethoxy-5-pyrrolyl)succinic anhydrides were obtained by the reaction of pyrrole and 2,4-dimethyl-3-carbethoxypyrrole with maleic anhydride. (2,4-Dimethyl-3-carbethoxy-5-pyrrolyl)succinic acid and its imides and dialkylamides were synthesized by hydrolysis and aminolysis of the anhydrides.

S. G. Agbalyan; K. G. Oganesyan

1972-01-01

275

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

276

Time-resolved Properties and Global Trends in dMe Flares from Simultaneous Photometry and Spectra  

NASA Astrophysics Data System (ADS)

We present a homogeneous analysis of line and continuum emission from simultaneous high-cadence spectra and photometry covering near-ultraviolet and optical wavelengths for 20 M dwarf flares. These data were obtained to study the white-light continuum components at bluer and redder wavelengths than the Balmer jump. Our goals were to break the degeneracy between emission mechanisms that have been fit to broadband colors of flares and to provide constraints for radiative-hydrodynamic (RHD) flare models that seek to reproduce the white-light flare emission. The main results from the analysis are the following: (1) the detection of Balmer continuum (in emission) that is present during all flares and with a wide range of relative contributions to the continuum flux at bluer wavelengths than the Balmer jump; (2) a blue continuum at flare maximum that is linearly decreasing with wavelength from ? = 4000-4800 Å, indicative of hot, blackbody emission with typical temperatures of T BB ~ 9000-14, 000 K (3) a redder continuum apparent at wavelengths longer than H? (? >~ 4900 Å) which becomes relatively more important to the energy budget during the late gradual phase. The hot blackbody component and redder continuum component have been detected in previous studies of flares. However, we have found that although the hot blackbody emission component is relatively well-represented by a featureless, single-temperature Planck function, this component includes absorption features and has a continuum shape strikingly similar to the spectrum of an A-type star as directly observed in our flare spectra. New model constraints are presented for the time evolution among the hydrogen Balmer lines and between Ca II K and the blackbody continuum emission. We calculate Balmer jump flux ratios and compare to the solar-type flare heating predictions from RHD models. The model ratios are too large and the blue-optical (? = 4000-4800 Å) slopes are too red in both the impulsive and gradual decay phases of all 20 flares. This discrepancy implies that further work is needed to understand the heating at high column mass during dMe flares. Based on observations obtained with the Apache Point Observatory 3.5 m telescope, which is owned and operated by the Astrophysical Research Consortium.

Kowalski, Adam F.; Hawley, Suzanne L.; Wisniewski, John P.; Osten, Rachel A.; Hilton, Eric J.; Holtzman, Jon A.; Schmidt, Sarah J.; Davenport, James R. A.

2013-07-01

277

TIME-RESOLVED PROPERTIES AND GLOBAL TRENDS IN dMe FLARES FROM SIMULTANEOUS PHOTOMETRY AND SPECTRA  

SciTech Connect

We present a homogeneous analysis of line and continuum emission from simultaneous high-cadence spectra and photometry covering near-ultraviolet and optical wavelengths for 20 M dwarf flares. These data were obtained to study the white-light continuum components at bluer and redder wavelengths than the Balmer jump. Our goals were to break the degeneracy between emission mechanisms that have been fit to broadband colors of flares and to provide constraints for radiative-hydrodynamic (RHD) flare models that seek to reproduce the white-light flare emission. The main results from the analysis are the following: (1) the detection of Balmer continuum (in emission) that is present during all flares and with a wide range of relative contributions to the continuum flux at bluer wavelengths than the Balmer jump; (2) a blue continuum at flare maximum that is linearly decreasing with wavelength from {lambda} = 4000-4800 A, indicative of hot, blackbody emission with typical temperatures of T{sub BB} {approx} 9000-14, 000 K; (3) a redder continuum apparent at wavelengths longer than H{beta} ({lambda} {approx}> 4900 A) which becomes relatively more important to the energy budget during the late gradual phase. The hot blackbody component and redder continuum component have been detected in previous studies of flares. However, we have found that although the hot blackbody emission component is relatively well-represented by a featureless, single-temperature Planck function, this component includes absorption features and has a continuum shape strikingly similar to the spectrum of an A-type star as directly observed in our flare spectra. New model constraints are presented for the time evolution among the hydrogen Balmer lines and between Ca II K and the blackbody continuum emission. We calculate Balmer jump flux ratios and compare to the solar-type flare heating predictions from RHD models. The model ratios are too large and the blue-optical ({lambda} = 4000-4800 A) slopes are too red in both the impulsive and gradual decay phases of all 20 flares. This discrepancy implies that further work is needed to understand the heating at high column mass during dMe flares.

Kowalski, Adam F.; Hawley, Suzanne L.; Davenport, James R. A. [Astronomy Department, University of Washington, Box 351580, U.W. Seattle, WA 98195-1580 (United States); Wisniewski, John P. [HL Dodge Department of Physics and Astronomy, University of Oklahoma, 440 W Brooks Street, Norman, OK 73019 (United States); Osten, Rachel A. [Space Telescope Science Institute, 3700 San Martin Drive Baltimore, MD 21218 (United States); Hilton, Eric J. [Universe Sandbox, Seattle, WA (United States); Holtzman, Jon A. [Department of Astronomy, New Mexico State University, Box 30001, Las Cruces, NM 88003 (United States); Schmidt, Sarah J., E-mail: adam.f.kowalski@nasa.gov [Department of Astronomy, Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States)

2013-07-15

278

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

279

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

280

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

281

Crown ether functionalized texaphyrin monomers and dimers‡  

PubMed Central

The synthesis and characterization of two 18-crown-6 functionalized analogues of an extensively studied gadolinium texaphyrin derivative, motexafin gadolinium (1, MGd), are reported. These are the monomeric and dimeric species, compounds 2 and 3, respectively. Both crown ether functionalized species proved to be stable at physiological pH and revealed distinct shifts in the UV spectrum when treated with sodium-, potassium-, ammonium- or zinc(II)-salts. Zinc(II) is believed to play a major role regulating apoptosis mechanisms in cancerous cells. Therefore, cytotoxicity studies of 2 and 3 were carried out using Ramos cell lines in the presence and absence of zinc(II). PMID:22025887

Preihs, Christian; Magda, Darren; Sessler, Jonathan L.

2011-01-01

282

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

283

21 CFR 524.660a - Dimethyl sulfoxide solution.  

Code of Federal Regulations, 2013 CFR

...HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED...AND TOPICAL DOSAGE FORM NEW ANIMAL DRUGS § 524.660a Dimethyl...per day. Total duration of therapy should not exceed 30 days...per day. Total duration of therapy should not exceed 14...

2013-04-01

284

21 CFR 524.660b - Dimethyl sulfoxide gel.  

Code of Federal Regulations, 2011 CFR

...HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED...AND TOPICAL DOSAGE FORM NEW ANIMAL DRUGS § 524.660b Dimethyl...per day. Total duration of therapy should not exceed 30 days...per day. Total duration of therapy should not exceed 14...

2011-04-01

285

21 CFR 524.660b - Dimethyl sulfoxide gel.  

Code of Federal Regulations, 2013 CFR

...HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED...AND TOPICAL DOSAGE FORM NEW ANIMAL DRUGS § 524.660b Dimethyl...per day. Total duration of therapy should not exceed 30 days...per day. Total duration of therapy should not exceed 14...

2013-04-01

286

21 CFR 524.660a - Dimethyl sulfoxide solution.  

Code of Federal Regulations, 2012 CFR

...HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED...AND TOPICAL DOSAGE FORM NEW ANIMAL DRUGS § 524.660a Dimethyl...per day. Total duration of therapy should not exceed 30 days...per day. Total duration of therapy should not exceed 14...

2012-04-01

287

21 CFR 524.660b - Dimethyl sulfoxide gel.  

Code of Federal Regulations, 2010 CFR

...HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED...AND TOPICAL DOSAGE FORM NEW ANIMAL DRUGS § 524.660b Dimethyl...per day. Total duration of therapy should not exceed 30 days...per day. Total duration of therapy should not exceed 14...

2010-04-01

288

21 CFR 524.660b - Dimethyl sulfoxide gel.  

Code of Federal Regulations, 2012 CFR

...HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED...AND TOPICAL DOSAGE FORM NEW ANIMAL DRUGS § 524.660b Dimethyl...per day. Total duration of therapy should not exceed 30 days...per day. Total duration of therapy should not exceed 14...

2012-04-01

289

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...

290

40 CFR 721.4128 - Dimethyl-3-substituted heteromonocycle.  

Code of Federal Regulations, 2010 CFR

(1) The chemical substance identified generically as dimethyl-3-substituted heteromonocycle (PMN No. P-91-1322) is subject to reporting under this section for the significant new uses described in paragraph (a)(2) of this section. (2) The significant new uses...

2010-07-01

291

40 CFR 63.62 - Redefinition of glycol ethers listed as hazardous air pollutants.  

Code of Federal Regulations, 2010 CFR

...pollutants. The following definition of the glycol ethers category of hazardous air pollutants...S.C. 7412(b)(1), footnote 2: Glycol ethers include mono- and di-ethers of ethylene glycol, diethylene glycol, and triethylene...

2010-07-01

292

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

293

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

Code of Federal Regulations, 2011 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...

2011-07-01

294

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

Microsoft Academic Search

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

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

2006-01-01

295

Effects of dimethyl fumarate on neuroprotection and immunomodulation  

PubMed Central

Background Neuronal degeneration in multiple sclerosis has been linked to oxidative stress. Dimethyl fumarate is a promising novel oral therapeutic option shown to reduce disease activity and progression in patients with relapsing-remitting multiple sclerosis. These effects are presumed to originate from a combination of immunomodulatory and neuroprotective mechanisms. We aimed to clarify whether neuroprotective concentrations of dimethyl fumarate have immunomodulatory effects. Findings We determined time- and concentration-dependent effects of dimethyl fumarate and its metabolite monomethyl fumarate on viability in a model of endogenous neuronal oxidative stress and clarified the mechanism of action by quantitating cellular glutathione content and recycling, nuclear translocation of transcription factors, and the expression of antioxidant genes. We compared this with changes in the cytokine profiles released by stimulated splenocytes measured by ELISPOT technology and analyzed the interactions between neuronal and immune cells and neuronal function and viability in cell death assays and multi-electrode arrays. Our observations show that dimethyl fumarate causes short-lived oxidative stress, which leads to increased levels and nuclear localization of the transcription factor nuclear factor erythroid 2-related factor 2 and a subsequent increase in glutathione synthesis and recycling in neuronal cells. Concentrations that were cytoprotective in neuronal cells had no negative effects on viability of splenocytes but suppressed the production of proinflammatory cytokines in cultures from C57BL/6 and SJL mice and had no effects on neuronal activity in multi-electrode arrays. Conclusions These results suggest that immunomodulatory concentrations of dimethyl fumarate can reduce oxidative stress without altering neuronal network activity. PMID:22769044

2012-01-01

296

Chemistry of dimethyl sulfide in the equatorial Pacific atmosphere  

SciTech Connect

A field study of the chemistry of dimethyl sulfide (DMS) was conducted on the island of Kiritimati (Christmas Island) during July and August, 1994. This island is located at 2{degrees}N, 157{degrees}W approximately 2000km south of Hawaii. The authors obtained a very repeatable diurnal variation for both DMS and sulfur dioxide (SO{sub 2}) during two 5-day and one 2-day experiments. Near sunrise DMS was about 200pptv. It decreased to about 120 pptv by late afternoon. During the daytime SO{sub 2} increased from about 20 pptv to about 75 pptv. At night DMS increased and SO{sub 2} decreased almost linearly. About 62% of the DMS was converted to SO{sub 2}. DMS was emitted from the ocean at an average flux of 3.7 x 10{sup 13} molecules in m{sup {minus}2}s{sup {minus}1}. The average dry deposition velocity of SO{sub 2} was 6.8 mm sec{sup {minus}1} Most of the SO{sub 2} appeared to be lost to the ocean although a comparable but not significantly larger flux to aerosol cannot be ruled out. Dimethyl sulfoxide was in the range 10 to 50 pptv with a mean of about 25 pptv. Dimethyl sulfone was in the range 0 to 15 pptv with a mean of about 3 pptv. There was no diurnal trend in other species. A much smaller fraction of the DMS was converted to dimethyl sulfone than dimethyl sulfoxide. 27 refs., 2 fig., 2 tab.

Bandy, A.R.; Thornton, D.C.; Blomquist, B.W. [Drexel Univ., Philadelphia, PA (United States)] [and others] [Drexel Univ., Philadelphia, PA (United States); and others

1996-04-01

297

21 CFR 520.1846 - Polyoxyethylene (23) lauryl ether blocks.  

Code of Federal Regulations, 2010 CFR

...Polyoxyethylene (23) lauryl ether blocks. 520.1846 Section...CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS...Polyoxyethylene (23) lauryl ether blocks. (a) Specifications...Initially, provide one block per five head of cattle...this product. Do not feed this product to...

2010-04-01

298

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

299

Safety assessment of alkyl glyceryl ethers as used in cosmetics.  

PubMed

Alkyl glyceryl ethers function mostly as skin-conditioning agents in cosmetic products applied to the skin and hair. The Cosmetic Ingredient Review expert panel reviewed the available animal toxicity and clinical data, including the low dermal absorption, and concluded that the alkyl glyceryl ethers are safe in the present practices of use and concentration described in this safety assessment. PMID:24174475

Johnson, Wilbur; Bergfeld, Wilma F; Belsito, Donald V; Hill, Ronald A; Klaassen, Curtis D; Liebler, Daniel; Marks, James G; Shank, Ronald C; Slaga, Thomas J; Snyder, Paul W; Andersen, F Alan

2013-01-01

300

Polybrominated Diphenyl Ethers in the Sediments of the Great Lakes.  

E-print Network

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

Rockne, Karl J.

301

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

302

Cyclic imino ethers in practical step-growth polymerizations  

SciTech Connect

Dicarboxylic acids, glycols, diamines, epoxy resins, phenolics, etc., have significant uses in a variety of thermoplastics and thermosets. Cyclic imino ethers may be used to react with the functionalities on the aforesaid starting compounds, providing practical paths to a host of improved performance materials. For example, the dicarboxylic acid-cyclic imino ether reaction may be employed to produce super tough, poly(amide-ester) thermosets. Or, phenolics may be chain extended and/or crosslinked with cyclic imino ethers to produce poly(amide-ether) thermosets with highly attractive thermal, physical and mechanical properties, with a wide variety of composite applications. In the recycling area, it is also very practical to use cyclic imino ethers to chain extend, i.e., enhance the molecules weight, of recovered polyesters or polyamides to enhance performance of the recovered materials. The use of monomers and polymers containing two or more cyclic imino ether moieties for production of new materials will be discussed. The phenolic hydroxyl-cyclic imino ether reaction will receive the main focus as a practical route to new poly(amide-ether) thermosets, based on the authors experience in using this chemistry to design matrix resins for high performance composities.

Culbertson, B.M. [Ohio State Univ., Columbus, OH (United States)

1993-12-31

303

IRIS TOXICOLOGICAL REVIEW OF PENTABROMODIPHENYL ETHER (EXTERNAL REVIEW DRAFT)  

EPA Science Inventory

The U.S. EPA is conducting a peer review of the scientific basis supporting the human health hazard and dose-response assessments of congeners of polybrominated diphenyl ethers (PDBEs), this review is about 2,2',4,4',5-Pentabromodiphenyl Ether, or commonly referred to as PentaBDE...

304

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

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

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

305

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

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

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

306

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

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

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

307

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

308

Preparation of highly fluorinated diols containing ether linkages.  

NASA Technical Reports Server (NTRS)

Hydroxy-terminated perfluoroethers and polyurethane resins derived from ethers have outstanding chemical resistance and good thermal properties. They can be used as potting compounds, coatings, and seals. The hydroxy-terminated ethers serve as intermediates in the synthesis of highly fluorinated elastomers and adhesives.

Rochow, S. E.; Stump, E. C., Jr.

1970-01-01

309

Determination of decabromodiphenyl ether in backcoated textile preparation.  

PubMed

A simple and reproducible chromatographic method for determination of decabromodiphenyl ether (DBDPE) is presented. The mobile phase consisted of aqueous acetonitrile solution. A simple quantitative extraction method using a soxhlet extraction is proposed to extract decabromodiphenyl ether from textile backcoated sample, and, a rapid chromatographic method using spectrophotometric detection, is described for the determination of decabromodiphenyl ether. The proposed method is applied for the determination of the decabromodiphenyl ether in a backcoated textile. Complete methods validation for both the extraction and analytical methods are discussed. Linear calibration curve in a range of 0.3-300.0mg/microL is achieved with a detection limit of 0.1microg. The method is successfully applied to the determination of decabromodiphenyl ether in several backcoated formulations. PMID:18599211

Ghanem, Raed; Baker, Hutaf

2009-02-15

310

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

311

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

PubMed Central

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

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

2014-01-01

312

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

SciTech Connect

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

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

2009-01-01

313

AN EFFICIENT METHOD FOR SELECTIVE DEPROTECTION OF TRIMETHYLSILYL ETHERS, TETRAHYDROPYRANYL ETHERS, ETHYLENE ACETALS, AND KETALS UNDER MICROWAVE IRRADIATION  

Microsoft Academic Search

1-Benzyl-4-aza-1-azoniabicyclo[2.2.2]octane dichromate (BAABOD) is a useful reagent for the selective cleavage of trimethylsilyl ethers, tetrahydropyranyl ethers, ethylene acetals and ketals to their corresponding alcohols, aldehydes and ketones. This method is very simple and efficient and the reaction has been carried out under microwave irradiation.

A. R. Hajipour; S. E. Mallakpour; I. Mohammadpoor-Baltork; S. Khoee

2002-01-01

314

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

Microsoft Academic Search

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

Shin Hasegawa; Yasuyuki Suzuki; Yasunari Maekawa

2008-01-01

315

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

Code of Federal Regulations, 2010 CFR

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

2010-07-01

316

A sulfonated poly (aryl ether ether ketone ketone) isomer: synthesis and DMFC performance  

SciTech Connect

A sulfonated poly(aryl ether ether ketone ketone) (PEEKK) having a well-defined rigid homopolymer-like chemical structure was synthesized from a readily-prepared PEEKK post-sulfonation with concentrated sulfuric acid at room temperature within several hours. The polymer electrolyte membrane (PEM) cast from the resulting polymer exhibited an excellent combination of thermal resistance, oxidative and dimensional stability, low methanol fuel permeability and high proton conductivity. Furthermore, membrane electrode assemblies (MEAs) were successfully fabricated and good direct methanol fuel cell (DMFC) performance was observed. At 2 M MeOH feed, the current density at 0.5 V reached 165 mA/cm, which outperformed our reported analogues and eveluated Nafion membranes.

Kim, Yu Seung [Los Alamos National Laboratory; Liu, Baijun [JILIN UNIV.; Hu, Wei [JILIN UNIV.; Jiang, Zhenhua [JILIN UNIV.; Robertson, Gilles [CANADA NRC; Guiver, Michael [CANADA NRC

2009-01-01

317

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

318

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

319

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.

320

Synthesis of amphiphilic 6-carboxypullulan ethers.  

PubMed

Hydrophobically modified polysaccharides that contain carboxyl groups possess exceptional features for drug delivery and other applications. Carboxyl groups were introduced at C-6 in the pullulan backbone by applying the well-established oxidation with TEMPO and NaOCl/NaBr. The oxidized product, 6-carboxypullulan, is even more water-soluble than pullulan. Consequently, further chemical modifications have been mainly restricted to reactions that can be performed in water or under heterogeneous conditions. We find that the TBA salt of 6-carboxypullulan is soluble in a range of organic solvents and can be reacted homogeneously with various alkyl halides in DMSO and sodium hydroxide at 40 °C to yield 6-carboxypullulan ethers. Complete substitution (DS 7 per trisaccharide repeat unit) was achieved upon reaction with iodoethane, while products from reaction with longer chain alkyl halides (propyl and butyl derivatives) achieved DS up to about 3. The amphiphilic products have impressive surfactant properties. PMID:24188839

Pereira, Junia M; Mahoney, Michelle; Edgar, Kevin J

2014-01-16

321

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.

322

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

SciTech Connect

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

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

2009-01-01

323

Effect of ethylene glycol monomethyl ether and diethylene glycol monomethyl ether on hepatic metabolizing enzymes.  

PubMed

Glycol ethers have been extensively used in industry over the past 40-50 years. Numerous studies on the toxicity of glycol ethers have been performed, however, the effects of glycol ethers on the hepatic drug metabolizing enzymes are still unknown. We studied the changes of the putative metabolic enzymes, that is, the hepatic microsomal mixed function oxidase system and cytosolic alcohol dehydrogenase, by the oral administration of diEGME and EGME. Adult male Wistar rats were used. DiEGME was administered orally; 500, 1000, 2000 mg/kg for 1, 2, 5 or 20 days and EGME was 100, 300 mg/kg for 1, 2, 5 or 20 days. Decreases in liver weights were produced by highest doses of diEGME (2000 mg/kg body wt/day for 20 days) and EGME (300 mg/kg body wt/day for 20 days). DiEGME increased hepatic microsomal protein contents and induced cytochrome P-450, but not cytochrome b5 or NADPH-cytochrome c reductase. The activity of cytosolic ADH was not affected by diEGME administration. On the other hand, EGME did not change cytochrome P-450, cytochrome b5 or NADPH-cytochrome c reductase. The activity of cytosolic ADH was increased by repeated EGME treatment. Therefore it is suspected that the enzyme which takes part in the metabolism of diEGME is different from that of EGME, although diEGME is a structural homologue of EGME. PMID:2389243

Kawamoto, T; Matsuno, K; Kayama, F; Hirai, M; Arashidani, K; Yoshikawa, M; Kodama, Y

1990-06-01

324

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

325

Crown Ethers in Nonaqueous Electrolytes for Lithium/Air Batteries  

SciTech Connect

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

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

2010-02-04

326

Aspects of biological monitoring of exposure to glycol ethers.  

PubMed

Glycol ethers are frequently used as solvents, detergents, and emulsifiers alone or as components in industrial and consumer products. The monomethyl and monoethyl ethers of ethylene glycol, and their acetate esters, are teratogenic and embryotoxic and cause testicular damage in laboratory animals, while the monobutyl ether causes hemolysis of the red blood cells. The adverse effects are attributed to the acid metabolites methoxy-, ethoxy- and butoxyacetic acid, respectively. The glycol ethers may readily enter the body by inhalation as well as dermal uptake. Biological monitoring of exposure to glycol ethers has therefore been suggested. This paper reviews physical properties, occurrence, analysis, toxicity, and toxicokinetics of the most common glycol ethers and then discusses toxicokinetic aspects of biological monitoring. The effect of physical exercise and the relative importance of respiratory and percutaneous absorption on the internal exposure to glycol ethers are illustrated. Monitoring the acid metabolite in urine is suggested as the best index of exposure. Intra- and inter-individual variability, dose-dependent toxicokinetics, and metabolic induction and inhibition are examples of possible sources of error in the estimation of internal exposure from the urinary excretion of acid metabolite. PMID:3051527

Johanson, G

1988-10-01

327

Dimethyl sulphoxide and dimethyl sulphone are potent inhibitors of IL6 and IL8 expression in the human chondrocyte cell line C-28\\/I2  

Microsoft Academic Search

AimsReactive oxygen species (ROS) are highly diffusable and reactive molecules which modulate gene transcription, particularly of pro-inflammatory cytokines which play a crucial role in the nascency and progression of chronic inflammatory diseases such as rheumatoid arthritis (RA) and osteoarthritis (OA). Since thiols could be potent inhibitors of the production of cytokines, the effects of dimethyl sulphoxide (DMSO) and dimethyl sulphone

Burkhard Kloesch; Melissa Liszt; Johann Broell; Guenter Steiner

2011-01-01

328

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

329

Global Distribution of Halogenated Dimethyl Bipyrroles in Marine Mammal Blubber  

Microsoft Academic Search

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

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

2002-01-01

330

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

331

Photodegradation of dimethyl and di-2-ethylhexyl phthalates  

E-print Network

hexane and water was photodegraded by a 450-watt mercury vapor arc lamp in a quartz-cell. Several unidentified products were formed during the hexane solution photolysis. Aqueous solutions of DEHP were not good models for the study of phthalate photo...- lysis because of the very poor water solubility of DEHP. Dimethyl phthalate (DMP) was a better model. DEHP was photodegraded more efficiently than DMP in aqueous solution. Relative efficiencies of photodegradation of DMP using filters were quartz...

Hammargren, Thomas Fredric

2012-06-07

332

Chemicals as peak shaving agents in IGCC based power plants  

SciTech Connect

Coal gasification generates a very impure synthesis gas, which before use in gas turbines for Integrated Gasification Combined Cycle (IGCC) plants has to be cleaned thoroughly. The purification of such a gas may be done by hot gas cleaning to a level which allows the gas to be used for production of chemicals such as methanol or dimethyl ether (DME). Such a production may be attractive either for use of the substances as such in the chemical industry or as automotive fuels. Alternatively these fuels may also be used as gas turbine fuels for power production. In the latter case an interesting possibility exists in the form of chemical recuperation. Low grade heat is used in the catalytically based transformation of methanol or DME into hydrogen and carbon monoxide. The present paper deals with the hot gas cleaning processes and the catalytic processes involved in a power plant in which the produced methanol and/or DME is used for peak shaving purposes.

Hansen, J.B.; Aasberg-Petersen, K.; Sigurdardottir, D.; Nielsen, H. [Haldor Topsoe A/S (Denmark)

1998-12-31

333

Free-radical metabolites of acetaminophen and a dimethylated derivative.  

PubMed

The oxidation of acetaminophen (4'-hydroxyacetanilide) to the corresponding N-acetyl-p-benzoquinone imines by plant and mammalian peroxidases is discussed. The acetaminophen free radical (N-acetyl-4-aminophenoxyl) has been reported as an intermediate. It is very reactive and forms melanin-like polymeric products. Application of a fast-flow system makes it possible to detect the transient species and clearly distinguish it from persistent paramagnetic melanin polymers. A model system, leading to more stable metabolites, can be obtained by introduction of methyl groups next to the oxygen, 3',5'-dimethylacetaminophen (3',5'-dimethyl-4'-hydroxyacetanilide). The ESR spectrum of the free radical formed could be completely analyzed and confirmed by deuterium substitution. The data are consistent with the assignment to a phenoxyl free radical (N-acetyl-2,6-dimethyl-4-amino-phenoxyl). Its formation is discussed in terms of substrate, hydrogen peroxide and enzyme concentration dependence. It is believed to be formed via a direct one-electron oxidation of 3',5'-dimethyl-4'-hydroxy-acetanilide. The radical does not form polymers or react with nucleophiles. Its redox behavior is discussed. The possible reaction of these phenoxyl free radicals with oxygen is thought to be negligible. PMID:3007084

Fischer, V; West, P R; Harman, L S; Mason, R P

1985-12-01

334

Free-radical metabolites of acetaminophen and a dimethylated derivative.  

PubMed Central

The oxidation of acetaminophen (4'-hydroxyacetanilide) to the corresponding N-acetyl-p-benzoquinone imines by plant and mammalian peroxidases is discussed. The acetaminophen free radical (N-acetyl-4-aminophenoxyl) has been reported as an intermediate. It is very reactive and forms melanin-like polymeric products. Application of a fast-flow system makes it possible to detect the transient species and clearly distinguish it from persistent paramagnetic melanin polymers. A model system, leading to more stable metabolites, can be obtained by introduction of methyl groups next to the oxygen, 3',5'-dimethylacetaminophen (3',5'-dimethyl-4'-hydroxyacetanilide). The ESR spectrum of the free radical formed could be completely analyzed and confirmed by deuterium substitution. The data are consistent with the assignment to a phenoxyl free radical (N-acetyl-2,6-dimethyl-4-amino-phenoxyl). Its formation is discussed in terms of substrate, hydrogen peroxide and enzyme concentration dependence. It is believed to be formed via a direct one-electron oxidation of 3',5'-dimethyl-4'-hydroxy-acetanilide. The radical does not form polymers or react with nucleophiles. Its redox behavior is discussed. The possible reaction of these phenoxyl free radicals with oxygen is thought to be negligible. PMID:3007084

Fischer, V; West, P R; Harman, L S; Mason, R P

1985-01-01

335

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

PubMed

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

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

2014-03-01

336

Photoresponsive surface molecularly imprinted poly(ether sulfone) microfibers.  

PubMed

In the present study, photoresponsive surface molecularly imprinted poly(ether sulfone) microfibers are prepared via nitration reaction, the wet-spinning technique, surface nitro reduction reaction, and surface diazotation reaction for the selectively photoregulated uptake and release of 4-hydrobenzoic acid. The prepared molecularly imprinted microfibers show selective binding to 4-HA under irradiation at 450 nm and release under irradiation at 365 nm. The simple, convenient, effective, and productive method for the preparation of azo-containing photoresponsive material is also applied to the modification of polysulfone and poly(ether ether ketone). All three benzene-ring-containing polymers show significant photoresponsibility after the azo modification. PMID:22894645

Wang, Dongsheng; Zhang, Xiaoxue; Nie, Shengqiang; Zhao, Weifeng; Lu, Yi; Sun, Shudong; Zhao, Changsheng

2012-09-18

337

EUVE J0825-16.3 and EUVE J1501-43.6: Two dMe Double-Lined Spectroscopic Binaries  

NASA Astrophysics Data System (ADS)

High-resolution echelle spectroscopic observations taken with the FEROS spectrograph at the ESO 2.2-m telescope confirm the binary nature of the dMe stars EUVE J082543.6, previously reported by Christian & Mathioudakis (2002). In these binary systems, emission of similar intensity from both components is detected in the Na i D1 & D2, He i D3, Ca II H& K, Ca II IRT and Balmer lines. We have determined precise radial velocities by cross-correlation with radial velocity standard stars, which have allowed us to obtain for the first time the orbital solution of these systems. Both binaries consist of two nearly equal M0V components with an orbital period shorter than 3.5 days. We have analyzed the behaviour of the chromospheric activity indicators (variability and possible flares). In addition, we have determined its rotational velocity and kinematics.

Montes, D.; Crespo-Chacón, I.; Gálvez, M. C.; Fernández-Figueroa, M. J.

2007-08-01

338

Thermal Conductivity of (DMe-DCNQI)2Li1-xCux (x=1 and 0.75): Anomalous Temperature Hysteresis Depending on Cu Concentration  

NASA Astrophysics Data System (ADS)

We have measured the thermal conductivity of organic molecular crystals (DMe-DCNQI)2Li1-xCux (x=1 and 0.75) over a wide temperature range between 4 and 250 K. The electronic contribution can be analyzed particularly below ˜80 K. A thermal hysteresis depending on the Cu concentration x has been observed between the heating and cooling processes. The system stays in a metallic state when the sample is cooled from room temperature, while a small fraction of insulating islands is created in the metallic state when heated up to room temperature. The insulating islands survive even at high temperatures. This mechanism gives rise to the hysteretic behavior. Heat conduction is sensitive to the difference in the two phases, in contrast with electrical resistivity.

Torizuka, Kiyoshi; Tajima, Hiroyuki; Yamamoto, Takashi

2006-07-01

339

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

Microsoft Academic Search

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

Tadashi Nakata; Sumihiro Nomura; Hiroko Matsukura

1996-01-01

340

THE MOUSE THAT ROARED: A SUPERFLARE FROM THE dMe FLARE STAR EV LAC DETECTED BY SWIFT AND KONUS-WIND  

SciTech Connect

We report on a large stellar flare from the nearby dMe flare star EV Lac observed by the Swift and Konus-Wind satellites and the Liverpool Telescope. It is the first large stellar flare from a dMe flare star to result in a Swift trigger based on its hard X-ray intensity. Its peak f{sub X} from 0.3 to 100 keV of 5.3 x 10{sup -8} erg cm{sup -2} s{sup -1} is nearly 7000 times larger than the star's quiescent coronal flux, and the change in magnitude in the white filter is {>=}4.7. This flare also caused a transient increase in EV Lac's bolometric luminosity (L{sub bol}) during the early stages of the flare, with a peak estimated L{sub X}/L{sub bol} {approx} 3.1. We apply flare loop hydrodynamic modeling to the plasma parameter temporal changes to derive a loop semi-length of l/R{sub *} = 0.37 {+-} 0.07. The soft X-ray spectrum of the flare reveals evidence of iron K{alpha} emission at 6.4 keV. We model the K{alpha} emission as fluorescence from the hot flare source irradiating the photospheric iron, and derive loop heights of h/R{sub *} = 0.1, consistent within factors of a few with the heights inferred from hydrodynamic modeling. The K{alpha} emission feature shows variability on timescales of {approx}200 s which is difficult to interpret using the pure fluorescence hypothesis. We examine K{alpha} emission produced by collisional ionization from accelerated particles, and find parameter values for the spectrum of accelerated particles which can accommodate the increased amount of K{alpha} flux and the lack of observed nonthermal emission in the 20-50 keV spectral region.

Osten, Rachel A. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Godet, Olivier [Universite de Toulouse, UPS, CESR, 9 Avenue du Colonel Roche, 31028 Toulouse Cedex 9 (France); Drake, Stephen; Tueller, Jack; Cummings, Jay; Krimm, Hans [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Pye, John [Department of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH (United Kingdom); Pal'shin, Valentin; Golenetskii, Sergei [Ioffe Physico-Technical Institute, Laboratory for Experimental Astrophysics, 26 Polytekhnicheskaya, St. Petersburg 194021 (Russian Federation); Reale, Fabio [Dip. Scienze Fis. and Astron., Sez. Astron., Universita di Palermo, P.za Parlamento 1, 90134 Palermo (Italy); Oates, Samantha R.; Page, Mat J. [Mullard Space Science Laboratory, University College London, Holmbury St. Mary, Dorking, Surrey RH5 6NT (United Kingdom); Melandri, Andrea, E-mail: osten@stsci.ed, E-mail: Olivier.Godet@cesr.f [Astrophysics Research Institute, Liverpool John Moores University, Twelve Quays House, Birkenhead CH41 1LD (United Kingdom)

2010-09-20

341

The Mouse That Roared: A Superflare from the dMe Flare Star EV Lac Detected by Swift and Konus-Wind  

NASA Astrophysics Data System (ADS)

We report on a large stellar flare from the nearby dMe flare star EV Lac observed by the Swift and Konus-Wind satellites and the Liverpool Telescope. It is the first large stellar flare from a dMe flare star to result in a Swift trigger based on its hard X-ray intensity. Its peak fX from 0.3 to 100 keV of 5.3 × 10-8 erg cm-2 s-1 is nearly 7000 times larger than the star's quiescent coronal flux, and the change in magnitude in the white filter is >=4.7. This flare also caused a transient increase in EV Lac's bolometric luminosity (L bol) during the early stages of the flare, with a peak estimated L X /L bol ~ 3.1. We apply flare loop hydrodynamic modeling to the plasma parameter temporal changes to derive a loop semi-length of l/R sstarf = 0.37 ± 0.07. The soft X-ray spectrum of the flare reveals evidence of iron K? emission at 6.4 keV. We model the K? emission as fluorescence from the hot flare source irradiating the photospheric iron, and derive loop heights of h/R sstarf = 0.1, consistent within factors of a few with the heights inferred from hydrodynamic modeling. The K? emission feature shows variability on timescales of ~200 s which is difficult to interpret using the pure fluorescence hypothesis. We examine K? emission produced by collisional ionization from accelerated particles, and find parameter values for the spectrum of accelerated particles which can accommodate the increased amount of K? flux and the lack of observed nonthermal emission in the 20-50 keV spectral region.

Osten, Rachel A.; Godet, Olivier; Drake, Stephen; Tueller, Jack; Cummings, Jay; Krimm, Hans; Pye, John; Pal'shin, Valentin; Golenetskii, Sergei; Reale, Fabio; Oates, Samantha R.; Page, Mat J.; Melandri, Andrea

2010-09-01

342

The Mouse that Roared: A SuperFlare from the dMe Flare Star EV Lac Detected by Swift and Konus-Wind  

NASA Astrophysics Data System (ADS)

We report on a large stellar flare from the nearby dMe flare star EV Lac observed by the Swift and Konus-Wind satellites and the Liverpool Telescope. It is the first large stellar flare from a dMe flare star to result in a Swift trigger based on its hard X-ray intensity. Its peak fx from 0.3-100 keV of 5.3×10-8 erg cm-2 s-1 is nearly 7000 times larger than the star's quiescent coronal flux, and the change in magnitude in the white filter is ?4.7. This flare also caused a transient increase in EV Lac's bolometric luminosity (Lbol) during the early stages of the flare, with a peak estimated LX/Lbol ˜3.1. We apply flare loop hydrodynamic modeling to the plasma parameter temporal changes to derive a loop semi-length of l/R?= 0.37±0.07. The soft X-ray spectrum of the flare reveals evidence of iron K? emission at 6.4 keV. We model the K? emission as fluorescence from the hot flare source irradiating the photospheric iron, and derive loop heights of h/R?=0.1, consistent within factors of a few with the heights inferred from hydrodynamic modeling. The K? emission feature shows variability on time scales of ˜200 s which is difficult to interpret using the pure fluorescence hypothesis. We examine K? emission produced by collisional ionization from accelerated particles, and find parameter values for the spectrum of accelerated particles which can accommodate the increased amount of K? flux and the lack of observed nonthermal emission in the 20-50 keV spectral region.

Osten, R. A.; Godet, O.; Drake, S.; Tueller, J.; Cummings, J.; Krimm, H.; Pye, J.; Pal'shin, V.; Golenetskii, S.; Reale, F.; Oates, S. R.; Page, M. J.; Melandri, A.

2011-12-01

343

Catalytic rearrangement of the chloroallyl ethers of p-cresol  

SciTech Connect

The rearrangement of a series of p-cresol ethers (..beta..- and ..gamma..-chloro-, ..beta gamma..- and ..beta gamma..,..gamma..-trichloroallyl), catalyzed by boron trifluoride etherate, was studied. Increase in the number of chlorine atoms in the allyl unit of the ether hinders the rearrangement, and its mechanism changes in the investigated series of ethers from intramolecular (3,3)-sigmatropic (with inversion of the allyl unit) to intermolecular, which corresponds to electrophilic substitution in the aromatic ring (without inversion). The presence of the chlorine atom at the ..beta.. position of the allyl unit promotes rearrangement by a concerted intramolecular mechanism, while a chlorine atom at the ..gamma.. position promotes rearrangement by an intermolecular stage mechanism. Two chlorine atoms at the ..gamma.. position give rise mainly to the intermolecular rearrangement path.

Andreev, N.A.; Bunina-Krivorukova, L.I.; Levashova, V.I.

1986-07-20

344

Tough poly(arylene ether) thermoplastics as modifiers for bismaleimides  

NASA Technical Reports Server (NTRS)

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

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

1989-01-01

345

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...

346

FLUORINATED ETHERS--A NEW SERIES OF CFC SUBSTITUTES  

EPA Science Inventory

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

347

Perfluoro copolymers of tetrafluoroethylene and perflouro alkyl vinyl ethers  

US Patent & Trademark Office Database

In preparing a fluorinated thermoplastic with good flex life, high thermal conductivity and low average spherolite diameter from tetrafluoroethylene and perfluoro n-alkyl vinyl ether, perfluoro 2-propoxyalkyl vinyl ether is additionally incorporated into the fluorinated thermoplastic. A semicrystalline, thermoplastically processable copolymer is prepared, made from units of the tetrafluoroethylene, from 2 to 10% by weight of units of perfluoro n-propyl vinyl ether and from 0.1 to 6% by weight of units of perfluoro 2-propoxypropyl vinyl ether. The novel copolymer preferably contains fewer than 70 unstable end groups per 10.sup.6 carbon atoms, has thermal conductivity of at least 0.19 W/mK at 23.degree. C. and has a smooth surface with an average spherolite diameter of <5 .mu.m. The novel terpolymer is suitable for extrusion of hose, in particular for heat exchangers, and also for ultrahigh-purity applications.

2004-02-03

348

Molecular Mechanism of Polybrominated Diphenyl Ether Disposition in the Liver  

E-print Network

Polybrominated diphenyl ethers (PBDEs) were introduced in the late 1970's as additive flame retardants incorporated into textiles, electronics, plastics and furniture. Although 2,2',3,3',4,4',5,5',6,6'-decabromodiphenyl ...

Pacyniak, Erik Kristofer

2010-10-01

349

Reactions involving shifting of the double bond in cyclic ethers  

SciTech Connect

4-Methylenetetrahydropyran undergoes isomerization to 4-methyl-5,6-dihydropyran in the presence of sodium on aluminum oxide. Both pyrans are converted to a vinyl ether, viz., 4-methyl-2,3-dihydropyran, under the influence of iron pentacarbonyl.

Ibatullin, U.G.; Petrushina, T.F.; Akhmadeeva, A.A.; Safarov, M.G.

1985-09-01

350

ANAEROBIC MICROBIAL REDUCTIVE DEBROMINATION OF POLYBROMINATED DIPHENYL ETHERS  

EPA Science Inventory

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

351

Radical Arylation of Phenols, Phenyl ethers, Furans und Phenylamines  

E-print Network

Radical Arylation of Phenols, Phenyl ethers, Furans und Phenylamines Technology offer TUM 2008-09E or furans. Aro- matic amines or hydroxy groups do not need to be proctected. Customer benefits Application

352

Oxidation of Benzyl Ethers via Phase Transfer Catalysis  

Microsoft Academic Search

A convenient procedure for the oxidation of benzyl ethers to benzoate esters is reported. Potassium permanganate in dichloromethane with phase transfer catalysis by triethylbenzylammonium chloride (TEBAC) affords products regiospecifically in fair to excellent yields.

J. Hodge Markgraf; Bo Yoon Choi

1999-01-01

353

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

EPA Science Inventory

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

354

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

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

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

355

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

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

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

356

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

EIA Publications

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

2006-01-01

357

Hydrogenolysis of dimethyl disulfide in the presence of bimetallic sulfide catalysts  

Microsoft Academic Search

The hydrogenolysis of dimethyl disulfide in the presence of Ni,Mo and Co,Mo bimetallic sulfide catalysts was studied at atmospheric\\u000a pressure and T = 160–400C. At T ? 200C, dimethyl disulfide undergoes hydrogenolysis at the S-S bond, yielding methanethiol in 95–100% yield. The selectivity\\u000a of the reaction decreases with increasing residence time and temperature due to methanethiol undergoing condensation to dimethyl

A. V. Mashkina; L. N. Khairulina

2007-01-01

358

UV-radiation curing of vinyl ether-based coatings  

Microsoft Academic Search

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

C. Decker; F. Morel; D. Decker

2000-01-01

359

Responsive supramolecular gels constructed by crown ether based molecular recognition.  

PubMed

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

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

2009-01-01

360

Crown ethers attenuate aggregation of amyloid beta of Alzheimer's disease.  

PubMed

In this report, we reasoned that non-covalent modification of amyloid beta (A?) by crown ethers could inhibit its aggregation. We demonstrated that PiB-C, a conjugate PiB and crown ether, could significantly reduce the aggregation in vitro. Additionally, two-photon imaging showed that PiB-C could efficiently label A? plaques and CAAs in AD mice. PMID:25372154

Tian, Yanli; Zhang, Xueli; Li, Yuyan; Shoup, Timothy M; Teng, Xin; Elmaleh, David R; Moore, Anna; Ran, Chongzhao

2014-12-25

361

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. PMID:9925565

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

1999-01-01

362

Nonlinear dielectric effect in supercritical diethyl ether  

NASA Astrophysics Data System (ADS)

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

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

2014-09-01

363

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

364

Mechanically reinforced phosphoric acid doped quaternized poly(ether ether ketone) membranes via cross-linking with functionalized graphene oxide.  

PubMed

Functionalized graphene oxide (FGO) reinforced quaternized poly(ether ether ketone) membranes were prepared for high temperature proton exchange membrane applications. The introduction of FGO significantly improved the mechanical strength and oxidative stability of these membranes at a high doping level. These reinforced membranes showed high tensile strength up to 40 MPa and high proton conductivity up to 58 mS cm(-1) at 200 °C. PMID:25350722

Zhang, Na; Wang, Baolong; Zhang, Yurong; Bu, Fanzhe; Cui, Ying; Li, Xuefeng; Zhao, Chengji; Na, Hui

2014-12-18

365

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. PMID:23284316

Gschwind, Fabienne; Jansen, Martin

2012-01-01

366

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

367

Sulphur-oxygen bond scission in ?-radiolysis of dimethyl sulphone  

NASA Astrophysics Data System (ADS)

Examination of the complex mixture of volatile products which has been derived in a previous study of the ?-radiolysis of dimethyl sulphone has revealed evidence that a mechanism involving sulphur-oxygen (S-O) bond scission of the radiation-induced radical cation of CH 3SO 2CH 3 may be operative in conjunction with the established mechanism of carbon-sulphur (C-S) bond scission. The existence of S-O bond scission is indicated by the observed formation of methanol from CH 3SO 2CH 3 (presumably via the rearranged radical cation [CH 3SO-OCH 3] +.) and other molecules containing the methoxy moiety.

Power, Alan J.

368

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

SciTech Connect

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

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

2008-01-01

369

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

370

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

371

Evaluation of the potential carcinogenicity of chloromethyl methyl ether (technical grade). Final report  

SciTech Connect

Technical grade chloromethyl methyl ether is contaminated with between 1 and 8 percent bis(chloromethyl)ether, which is a known human carcinogen. The human evidence for this compound and the hazard ranking are based on the evidence for bis(chloromethyl)ether. Technical grade chloromethyl methyl ether (which is always contaminated with bis(chloromethyl)ether) is therefore considered to be a human carcinogen, classified as weight-of-evidence Group A under the EPA Guidelines for Carcinogen Risk Assessment (U.S. EPA, 1986a). The evidence from human studies, including those for bis(chloromethyl)ether, is Sufficient. The evidence from animal studies on chloromethyl methyl ether alone is Inadequate. Combining the weight-of-evidence group and the potency group 1 for the contaminant bis(chloromethyl)ether, chlormethyl methyl ether is assigned a HIGH hazard ranking for the purposes of RQ adjustment.

Not Available

1988-06-01

372

Absorption of some glycol ethers through human skin in vitro.  

PubMed Central

To assist evaluation of the hazards of skin contact with selected undiluted glycol ethers, their absorption across isolated human abdominal epidermis was measured in vitro. Epidermal membranes were set up in glass diffusion cells and, following an initial determination of permeability to tritiated water, excess undiluted glycol ether was applied to the outer surface for 8 hr. The appearance of glycol ether in an aqueous "receptor" phase bathing the underside of the epidermis was quantified by a gas chromatographic technique. A final determination of tritiated water permeability was compared with initial values to establish any irreversible alterations in epidermal barrier function induced by contact with the glycol ethers. 2-methoxyethanol (EM) was most readily absorbed (mean steady rate 2.82 mg/cm2/hr), and a relatively high absorption rate (1.17 mg/cm2/hr) was also apparent for 1-methoxypropan-2-ol (PM). There was a trend of reducing absorption rate with increasing molecular weight or reducing volatility for monoethylene glycol ethers (EM, 2.82 mg/cm2/hr; 2-ethoxyethanol, EE, 0.796 mg/cm2/hr; 2-butoxyethanol, EB, 0.198 mg/cm2/hr) and also within the diethylene glycol series: 2-(2-methoxyethoxy) ethanol (DM, 0.206 mg/cm2/hr); 2-(2-ethoxyethoxy) ethanol (DE, 0.125 mg/cm2/hr) and 2-(2-butoxyethoxy) ethanol (DB, 0.035 mg/cm2/hr). The rate of absorption of 2-ethoxyethyl acetate (EEAc) was similar to that of the parent alcohol, EE. Absorption rates of diethylene glycol ethers were slower than their corresponding monoethylene glycol equivalents. Combination of intrinsic toxicity and ability to pass across skin contribute to assessment of hazards of contact with undiluted glycol ethers. PMID:6499804

Dugard, P H; Walker, M; Mawdsley, S J; Scott, R C

1984-01-01

373

Thermal transport of organic molecular crystals (DMe-DCNQI)2Li(1-x)Cux and observation of their super-lattice structure by means of synchrotron radiation X-ray  

NASA Astrophysics Data System (ADS)

We have measured the thermal conductivity for organic molecular crystals (DMe-DCNQI)2Li1-xCux (x=0, 0.08, and 0.14) over a wide range of temperatures (4˜250 K). A peak can be seen near ˜20 K. The peak height decreases with decreasing x, and it completely vanishes for x=0 specimen. This peak is created by a crossover between the phonon mean free path that diverges as T-2 and the phonon specific heat that decreases as T3. In addition, we have also succeeded in observing the super-lattice patterns of 4kF and 2kF of (DMe-DCNQI)2Li1-xCux (x=0 and 0.06) accompanied by the Peierls and the spin Peierls transitions by means of the synchrotron radiation X-ray in Tsukuba's Photon Factory.

Torizuka, Kiyoshi; Tajima, Hiroyuki; Kawamura, Yukihiko; Sawa, Hiroshi; Yamamoto, Takashi

2005-08-01

374

Dimethyl sulfoxide as an electron acceptor for anaerobic growth.  

PubMed

The isolation from lake mud of a bacterium which can use dimethyl sulfoxide (DMSO) as an electron acceptor for growth is described. The isolate, called strain DL-1, was a small, gram negative, non-motile spiral. The sole product of DMSO reduction was dimethyl sulfide (DMS). Other electron acceptors used by the isolate included sulfite, thiosulfate, elemental sulfur, methionine sulfoxide, tetramethylene sulfoxide, nitrate, and oxygen (microaerophilically). Sulfate was not reduced and could not even be assimilated. Lactate or succinate could serve as electron donors, with acetate as the main product. Hydrogen could be used as an electron donor if acetate was present in the medium as a carbon source. The organism has a c-type cytochrome, and most likely uses electron transport phosphorylation during DMSO reduction. Cultures of Desulfovibrio sp., Escherichia coli, Pseudomonas aeruginosa, and Proteus vulgaris were tested for growth using DMSO as an electron acceptor, and only the Proteus strain grew. Both Proteus and strain DL-1 are versatile at coupling reductions with energy generation. There is a marked resemblance between strain DL-1 and the recently described sulfur-reducing spirillum of Wolfe and Pfennig. PMID:414686

Zinder, S H; Brock, T D

1978-01-23

375

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

376

Identification of biogenic dimethyl selenodisulfide in the headspace gases above genetically modified Escherichia coli.  

PubMed

Escherichia coli JM109 cells were modified to express the genes encoded in a 3.8-kb chromosomal DNA fragment from a metalloid-resistant thermophile, Geobacillus stearothermophilus V. Manual headspace extraction was used to collect the gases for gas chromatography with fluorine-induced sulfur chemiluminescence analysis while solid-phase microextraction was used for sample collection in gas chromatography/mass spectrometry (GC/MS) analysis. When grown in the presence of selenate or selenite, these bacteria produced both organo-sulfur and organo-selenium in the headspace gases above the cultures. Organo-sulfur compounds detected were methanethiol, dimethyl sulfide, dimethyl disulfide, and dimethyl trisulfide. Organo-selenium compounds detected were dimethyl selenide and dimethyl diselenide. Two mixed sulfur-selenium compounds, dimethyl selenenyl sulfide and a chromatographically late-eluting compound, were detected. Dimethyl selenodisulfide, CH(3)SeSSCH(3), and dimethyl bis(thio)selenide, CH(3)SSeSCH(3), were synthesized and analyzed by GC/MS and fluorine-induced chemiluminescence to determine which corresponded to the late-eluting compound that was bacterially produced. CH(3)SeSSCH(3) was positively identified as the compound detected in bacterial headspace above Se-amended cultures. Using GC retention times, the boiling point of CH(3)SeSSCH(3) was estimated to be approximately 192 degrees C. This is the first report of CH(3)SeSSCH(3) produced by bacterial cultures. PMID:16289446

Swearingen, Jerry W; Frankel, Danielle P; Fuentes, Derie E; Saavedra, Claudia P; Vásquez, Claudio C; Chasteen, Thomas G

2006-01-01

377

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

EPA Science Inventory

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

378

Field Measurements of Dimethyl Sulphide and Its Oxidation Products in the Atmosphere  

Microsoft Academic Search

Dimethyl sulphide (DMS) is released into ocean waters by phytoplankton and may then cross the water-air interface into the atmosphere. Various models have been formulated to describe its behaviour in the atmosphere. Here, measurements of its concentrations and those of its major oxidation products, methane sulphonate, sulphur dioxide, non sea-salt sulphate and dimethyl sulphoxide, in both the gas and aerosol

C. Nicholas Hewitt; Brian Davison

1997-01-01

379

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

380

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

NASA Astrophysics Data System (ADS)

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

Wang, Li-Sheng; Tian, Na-Na

2011-06-01

381

Dimethyl fumarate: a review of its use in patients with relapsing-remitting multiple sclerosis.  

PubMed

Dimethyl fumarate (Tecfidera®) is a novel oral therapy that has recently been approved for the treatment of relapsing forms of multiple sclerosis (MS) and relapsing-remitting MS (RRMS). In preclinical studies, dimethyl fumarate exhibited anti-inflammatory and cytoprotective properties that are generally thought to be mediated via activation of the nuclear factor (erythroid-derived 2)-like 2 transcriptional pathway, which is involved in the cellular response to oxidative stress. In the large, double-blind, multinational, 2-year DEFINE and CONFIRM trials conducted in over 2,600 adult patients with RRMS, twice-daily oral dimethyl fumarate 240 mg was effective in reducing the proportion of patients with MS relapse at 2 years (primary endpoint of DEFINE) and the annualized relapse rate (primary endpoint of CONFIRM) compared with placebo, with reduced disability progression also observed with the drug versus placebo in DEFINE. Dimethyl fumarate also reduced disease activity measures relative to placebo in these trials, as assessed by magnetic resonance imaging. Dimethyl fumarate was generally well tolerated in patients with RRMS; adverse events that occurred more frequently in dimethyl fumarate than in placebo recipients included flushing and gastrointestinal events. The long-term efficacy and tolerability of dimethyl fumarate is currently being investigated in the ENDORSE trial, with interim results demonstrating that dimethyl fumarate was associated with continued efficacy for up to 4 years of treatment, with no new tolerability concerns. In conclusion, although more comparative data are needed to fully establish the relative efficacy and tolerability of dimethyl fumarate compared with other therapies, oral dimethyl fumarate is an important addition to the therapeutic options available for RRMS. PMID:24623127

Burness, Celeste B; Deeks, Emma D

2014-04-01

382

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

383

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

Code of Federal Regulations, 2011 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...

2011-07-01

384

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

385

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

NASA Astrophysics Data System (ADS)

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

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

2012-09-01

386

Exposure of Americans to polybrominated diphenyl ethers.  

PubMed

Polybrominated diphenyl ethers, PBDEs, are a class of brominated flame retardants that, like other persistent organic pollutants (POPs), have been found in humans, wildlife, and biota worldwide. Unlike other POPs, however, the key routes of human exposure are not thought to be food and fish, but rather are from their use in household consumer products, and to the high levels of PBDEs found in house dust. The exposure of Americans to PBDEs was systematically evaluated in this study. First, exposure media data on PBDE congeners were compiled. Then, an adult intake dose was derived using exposure factors in combination with these data. The exposure pathways evaluated included food and water ingestion, inhalation, and ingestion and dermal contact to house dust. These intakes were converted to a body burden using a simple pharmacokinetic (PK) model. The predicted body burdens were compared with representative profiles of PBDEs in blood and milk. The adult intake dose of total PBDEs was estimated to be 7.7 ng/kg body weight/day, and children's estimated intakes were higher at 49.3 ng/kg/day for ages 1-5, 14.4 ng/kg/day for 6-11, and 9.1 ng/kg/day for 12-19. The much higher dose for the child age 1-5 was due to the doubling of dust ingestion from 50 to 100 mg/day. The predicted adult body burden of total PBDEs was 33.8 ng/kg lipid weight (lwt), compared to representative measurements in blood and milk at 64.0 and 93.7 ng/g lwt, respectively Most of this apparent underprediction in total concentration was due to an underprediction of the key congener, BDE 47. The value for BDE 47 half-life in the body was identified as the variable most likely in error in this exercise. Other congener predictions compared well with measurements, suggesting general validity with the approach. An important finding from this assessment is that the food intake estimate of about 1.3 ng/kg/day (of the 7.7 ng/kg/day total) cannot explain current US body burdens; exposures to PBDEs in house dust accounted for 82% of the overall estimated intakes. PMID:17426733

Lorber, Matthew

2008-01-01

387

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

SciTech Connect

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

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

2009-01-01

388

Thermal oxidative degradation reactions of linear perfluoroalkyl ethers  

NASA Technical Reports Server (NTRS)

Thermal and thermal oxidative stability studies were performed on linear perfluoroalkyl ether fluids. The effect on degradation by metal catalysts and degradation inhibitors is reported. The linear perfluoroalkyl ethers are inherently unstable at 316 C in an oxidizing atmosphere. The metal catalysts greatly increased the rate of degradation in oxidizing atmospheres. In the presence of these metals in an oxidizing atmosphere, the degradation inhibitors were highly effective in arresting degradation at 288 C. However, the inhibitors had only limited effectiveness at 316 C. The metals promote degradation by chain scission. Based on elemental analysis and oxygen consumption data, the linear perfluoroalkyl ether fluids have a structural arrangement based on difluoroformyl and tetrafluoroethylene oxide units, with the former predominating. Previously announced in STAR as N82-26468

Jones, W. R., Jr.; Paclorek, K. J. L.; Ito, T. I.; Kratzer, R. H.

1983-01-01

389

Chikungunya virus vaccine prepared by Tween-ether extraction.  

PubMed

Chikungunya virus vaccines prepared by Tween 80 and ether inactivation of virus grown in green monkey kidney cell cultures were shown to be as immunogenic as comparable Formalin-inactivated vaccines. Both types of vaccine stimulated hemagglutination-inhibiting, complement-fixing, and neutralizing antibody and afforded protection to mice against a live virus challenge. It was shown after Tween-ether treatment of chikungunya virus that the infectivity of the virus was lost and the hemagglutinin titer was increased. By characterization of the resultant hemagglutinin by sucrose and cesium chloride density gradient centrifugation, it was found that the extracted particle was smaller in size and greater in density than the parent virus particle. Removal of lipid may account for the alterations in the physical characteristics of the infectious virus particle. Conditions for treatment of chikungunya virus with Tween and ether were found that preserved high titers of hemagglutinin as well as the immunogenicity of the virus preparations. PMID:4985431

Eckels, K H; Harrison, V R; Hetrick, F M

1970-02-01

390

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

391

Supramolecular polymers constructed by crown ether-based molecular recognition.  

PubMed

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

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

2012-03-01

392

18 O-selective IR MPD of perfluorodimethyl ether  

Microsoft Academic Search

The 18O-selective IR MPD of perfluorodimethyl ether (CF3)2O has been studied. The dissociation yields of (CF3)218O (ß18) and (CF3)216O (ß16) and the isotope selectivity a(18\\/16) have been measured as functions of TEA CO2-laser frequency, laser fluence and ether parent pressure. The (CF3)2O molecule has been found to provide highly efficient 18O separation. The MPD yield of the desired isotope 18O

V. B. Laptev; L. M. Tunamova; V. A. Kuz'menko; E. A. Ryabov

1990-01-01

393

18O-selective IR MPD of perfluorodimethyl ether  

Microsoft Academic Search

The 18O-selective IR MPD of perfluorodimethyl ether (CF3)2O has been studied. The dissociation yields of (CF3)2 18O (beta18) and (CF3)2 16O (beta16) and the isotope selectivity alpha(18\\/16) have been measured as functions of TEA CO2-laser frequency, laser fluence and ether parent pressure. The (CF3)2O molecule has been found to provide highly efficient 18O separation. The MPD yield of the desired

V. B. Laptev; L. M. Tunamova; V. A. Kuz'menko; E. A. Ryabov

1990-01-01

394

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

E-print Network

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

Burgess, Kevin

395

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

396

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

Code of Federal Regulations, 2011 CFR

...2011-07-01 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,...

2011-07-01

397

40 CFR 721.10220 - Phosphoric acid, polymer with cycloaliphatic diglycidyl ether, alkylethers (generic).  

Code of Federal Regulations, 2011 CFR

...2011-07-01 false Phosphoric acid, polymer with cycloaliphatic diglycidyl ether...Substances § 721.10220 Phosphoric acid, polymer with cycloaliphatic diglycidyl ether...identified generically as phosphoric acid, polymer with cycloaliphatic diglycidyl...

2011-07-01

398

POLYCHLORINATED BIPHENYLS AND POLYBROMINATED DIPHENYL ETHERS IN GALAPAGOS SEA LIONS (ZALOPHUS WOLLEBAEKI)  

E-print Network

), polybrominated diphenyl ethers (PBDEs), polychlorinated dibenzo-p- dioxins (PCDDs), and polychlorinated dibenzo-p-dioxins (PCDDs), and polychlorinated dibenzofurans (PCDFs) repre- sent persistentPOLYCHLORINATED BIPHENYLS AND POLYBROMINATED DIPHENYL ETHERS IN GALAPAGOS SEA LIONS (ZALOPHUS

Gobas, Frank

399

Unexpected Alternated Radical Copolymerization of Vinylidene cyanide with a Vinyl ether for Superhydrophobic and Highly  

E-print Network

1 Unexpected Alternated Radical Copolymerization of Vinylidene cyanide with a Vinyl ether Radical Copolymerization of Vinylidene cyanide with a Vinyl ether for Superhydrophobic and Highly) Abstract The synthesis and the characterization of original copolymers based on vinylidene cyanide (VCN

Paris-Sud XI, Université de

400

75 FR 28804 - An Exposure Assessment of Polybrominated Diphenyl Ethers (PBDEs)  

Federal Register 2010, 2011, 2012, 2013

...diphenyl ethers (PBDEs), a class of brominated flame retardants. It includes chapters on use and production...diphenyl ethers (PBDEs), a class of brominated flame retardants. The use of PBDEs as flame retardants in products associated with the...

2010-05-24

401

40 CFR 721.10518 - Diethylene glycol, polymer with diisocyanatoalkane, polyethylene glycol monomethyl ether- and...  

Code of Federal Regulations, 2013 CFR

40 Protection... false Diethylene glycol, polymer...monomethyl ether- and fluorinatedalkanol-blocked...generic). 721.10518 Section 721.10518 Protection...Substances § 721.10518 Diethylene glycol, polymer...monomethyl ether- and...

2013-07-01

402

Dimethyl fumarate (BG-12) for the treatment of multiple sclerosis.  

PubMed

Treatments for multiple sclerosis (MS) are only partially effective and most require a parenteral route of administration and/or may have severe side effects. Dimethyl fumarate is the active compound of BG-12 recently licensed for the treatment of relapsing-remitting MS. The pivotal Phase III trials have demonstrated an approximately 50% reduction of relapse rates compared with placebo paralleled by a reduction in new lesion formation on MRI. A dose of 240 mg two-times a day had an optimal effect. Flushing and gastrointestinal symptoms (diarrhea, abdominal pain, nausea) were common adverse events in the first month(s) of treatment. Severe side effects were not more common than in the placebo group for a treatment period of 2 years. The mode of action is not exactly clear and both immunomodulatory effects and an activation of the transcription factor Nrf2 are suggested. This new oral drug will be a welcome addition to existing MS treatments. PMID:23927662

Stangel, Martin; Linker, Ralf A

2013-07-01

403

Changes in Dimethyl Sulfide Oceanic Distribution due to Climate Change  

SciTech Connect

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

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

2011-02-16

404

Cathodic delaminations of poly(phenyl ether ether ketone) (PEEK) coatings overlaid on zinc phosphate-deposited steels  

SciTech Connect

The melt-crystallized poly(phenyl) ether ether ketone (PEEK) polymer was overlaid on crystalline zinc phosphate (Zn [center dot] Ph) conversion coating-deposited and nondeposited cold-rolled steels at 400 C in air or in N[sub 2] environments. The ability of these coatings systems to protect the steel against corrosion was evaluated from the rate of cathodic delamination of the coating layer from the steel. Because the cathodic reaction, H[sub 2]O + 1/20[sub 2] + 2e[sup [minus

Sugama, T.; Carciello, N.R. (Brookhaven National Lab., Upton, NY (United States). Dept. of Applied Science)

1993-12-10

405

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...

406

WEAR BEHAVIOR OF PAEK, POLY(ARYL-ETHER-KETONE),12 UNDER PHYSIOLOGICAL CONDITIONS, OUTLOOKS FOR13  

E-print Network

metal alloys. PEEK (Poly Ether Ether Ketone) and PEKK (Poly9 Ether Ketone Ketone)/CF (Carbon Fibers-4]. For instance, PEKK and its16 composites are manufactured for spinal implants. In this paper, the tribological to investigate the tribology of four polymers: UHMWPE, PEEK,19 PEKK and PEKK CF 30 % against the most usual

Paris-Sud XI, Université de

407

Reaction of the glycidyl ether of 2, 6-di-t-butylhydroquinone with secondary amines  

Microsoft Academic Search

1.The reaction of epichlorohydrin with 2,6-di-t-butylhydroquinone leads to the formation of the monoglycidyl ether of 2,6-di-t-butylhydroquinone.2.The reaction of the monoglycidyl ether of 2,6-di-t-butylhydroquinone with secondary amines leads to corresponding monohydroxyaminoalkyl ethers.

A. A. Volod'kin; V. V. Ershov; G. D. Ostapets-Sveshnikova

1966-01-01

408

2-Chloro-N-(2,6-dimethyl-phen-yl)acetamide  

PubMed Central

The crystal structure of the title compound (26DMPCA), C10H12ClNO, is closely related to those of side-chain-unsubstituted N-(2,6-dimethyl­phen­yl)acetamide and side-chain-substituted 2,2,2-trichloro-N-(2,6-dimethyl­phen­yl)­acet­amide and N-(2,6-dimethyl­phen­yl)-2,2,2-trimethylacet­amide, with slightly different bond parameters. The mol­ecules in 26DMPCA are linked into chains through N—H?O hydrogen bonding. PMID:21200852

Gowda, B. Thimme; Foro, Sabine; Svoboda, Ingrid; Paulus, Helmut; Fuess, Hartmut

2008-01-01

409

Tea saponin enhanced biodegradation of decabromodiphenyl ether by Brevibacillus brevis.  

PubMed

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

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

2014-11-01

410

Radiation chemistry of alternative fuel oxygenates -- Substituted ethers  

SciTech Connect

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

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

1999-11-15

411

Ether Stress Stimulates Noradrenaline Release in the Hypothalamic Paraventricular Nucleus  

Microsoft Academic Search

Differential normal-pulse voltammetry was combined with treated carbon fibre electrodes for monitoring in vivo extracellular catechols synthesized by noradrenergic terminals innervating the paraventricular hypothalamic nucleus. From urethane-anaesthetized rats, pretreated with a monoamine oxidase inhibitor, pargyline, we were able to monitor a catechol signal which unequivocally corresponded to extracellular noradrenaline, and we observed that ether inhalation for 2 min induced an

Claire C. Mermet; François G. Gorton

1988-01-01

412

POLYBROMINATED DIPHENYL ETHERS (PBDES) IN AMERICAN MOTHERS' MILK  

EPA Science Inventory

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

413

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

414

Polybrominated Diphenyl Ethers in the Sediments of the Great Lakes.  

E-print Network

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

Rockne, Karl J.

415

Polybrominated Diphenyl Ethers in the Sediments of the Great Lakes.  

E-print Network

Polybrominated Diphenyl Ethers in the Sediments of the Great Lakes. 2. Lakes Michigan and Huron W E the extent of PBDE pollution in the Great Lakes and provide evidence of their long-range transport via the atmosphere, a total of eight lakes, including the five Great Lakes and three inland seepage lakes

Rockne, Karl J.

416

Polybrominated Diphenyl Ethers in the Sediments of the Great Lakes.  

E-print Network

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

Rockne, Karl J.

417

EVALUATION OF THE POTENTIAL CARCINOGENICITY OF BIS (2-CHLOROETHYL) ETHER  

EPA Science Inventory

Bis(2-chloroethyl)ether is a probable human carcinogen, classified as weight-of-evidence Group B2 under the EPA Guidelines for Carcinogen Risk Assessment (U.S. EPA, 1986a). vidence on potential carcinogenicity from animal studies is "Sufficient," and the evidence from human studi...

418

EVALUATION OF THE POTENTIAL CARCINOGENICITY OF BIS(CHLOROMETHYL) ETHER  

EPA Science Inventory

Bis(chloromethyl)ether is a human carcinogen, classified as weight-of-evidence Group A under the EPA Guidelines for Carcinogen Risk Assessment (U.S. EPA, 1986a). vidence on potential carcinogenicity from animal studies is "Sufficient," and the evidence from human studies is "Suff...

419

Design of Chiral Auxiliaries for the Allene Ether Nazarov Cyclization  

PubMed Central

A 1,3- or a 1,4- cis axial tert-butyldimethylsilyloxy substituent on the pyranose derived chiral auxiliary for the allene ether Nazarov cyclization leads to products in high optical purity. ?-Pyranose and ?-pyranose derived auxiliaries lead to enantiomeric products. PMID:17425314

Banaag, April R.; Tius, Marcus A.

2008-01-01

420

IRIS Toxicological Review of Pentabromodiphenyl Ether (Final Report)  

EPA Science Inventory

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

421

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

422

FLUORINATED ETHERS--A NEW FAMILY OF HALONS?  

EPA Science Inventory

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

423

Dibenzo crown ether layer formation on muscovite mica.  

PubMed

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

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

2014-10-28

424

Developmental toxicity of four glycol ethers applied cutaneously to rats.  

PubMed Central

Previous NIOSH studies demonstrated the embryo- and fetotoxicity and teratogenicity of ethylene glycol monoethyl ether (EGEE) applied to the shaved skin of pregnant rats. In the present study ethylene glycol monoethyl ether acetate (EGEEA), ethylene glycol monobutyl ether (EGBE), and diethylene glycol monoethyl ether (diEGEE) were tested in the same experimental model, using distilled water as the negative control and EGEE as a positive control. Water or undiluted glycols were applied four times daily on days 7 to 16 of gestation to the shaved interscapular skin with an automatic pipetter. Volumes of EGEE (0.25 mL), EGEEA (0.35 mL), and diEGEE (0.35 mL) were approximately equimolar (2.6 mmole per treatment). EGBE at 0.35 mL four times daily (approximately 2.7 mmole per treatment) killed 10 of 11 treated rats, and was subsequently tested at 0.12 mL (0.9 mmole) per treatment. EGEE- and EGEEA-treated rats showed a reduction in body weight relative to water controls that was associated with completely resorbed litters and significantly fewer live fetuses per litter. Fetal body weights were also significantly reduced in those groups. Visceral malformations and skeletal variations were significantly increased in EGEE and EGEEA groups over the negative control group. No embryotoxic, fetotoxic, or teratogenic effects were detected in the EGBE- or diEGEE-treated litters. PMID:6499820

Hardin, B D; Goad, P T; Burg, J R

1984-01-01

425

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

426

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

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

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

427

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

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

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

428

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

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

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

429

AVOIDING HYDROLYSIS OF FUEL ETHER OXYGENATES DURING STATIC HEADSPACE ANALYSIS  

EPA Science Inventory

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

430

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

431

Traceless Chiral Auxiliaries for the Allene Ether Nazarov Cyclization  

PubMed Central

The key stereochemical factors that determine transfer of asymmetry from the chiral auxiliary to the cyclopentenone in the allene ether version of the Nazarov reaction have been elucidated. On the basis of the new insights into the mechanism two highly effective chiral auxiliaries were designed and prepared. PMID:18808186

Banaag, April R.; Tius, Marcus A.

2009-01-01

432

Comparative acute and subchronic toxicity of ethylene glycol monopropyl ether and ethylene glycol monopropyl ether acetate  

SciTech Connect

The acute toxicity of ethylene glycol monopropyl ether (EGPE) and ethylene-glycol monopropyl ether acetate (EGPEA) was determined in a series of standardized tests. The oral LD/sub 50/ in rats was 3089 and 9456 mg/kg EGPE and EGPEA, respectively. Skin irritation was slight following an occluded single dose application of either compound to the guinea pig abdomen. The dermal LD/sub 50/ for guinea pigs was 1 to 5 mL/kg and greater than 20 mL/kg EGPE and EGPEA, respectively. EGPE produced a very weak positive sensitization response in one of five guinea pigs. EGPE produced transient moderate to severe eye irritation in rabbits while EGPEA produced slight eye irritation. Subchronic toxicity was determined in a series of oral and inhalation studies. Groups of 10 male rats were dosed with 15, 7.5, 3.75 or 1.88 mmole/kg EGPE and 30, 15, or 7.5 mmole/kg EGPEA by gavage 5 days/week for 6 weeks. Hemoglobinuria was seen at least once at all dose levels of both compounds. EGPE had little effect on feed consumption or body weight gain, while body weight gain was reduced in the two high dose groups exposed to EGPEA and feed consumption was reduced at all dose levels. Hematologic changes were seen at all dose levels of both compounds. Absolute and/or relative spleen weights were increased at all but the lowest EGPE dose level and at all EGPEA dose levels. Gross and histopathologic examinations revealed significant effects on the spleen of animals exposed to EGPE and on the spleen, liver, kidney, and testes of animals exposed to EGPEA. Groups of 10 rats (5 M, 5 F) were exposed to 800, 400, 200 or 100 ppm EGPE or EGPEA 6 hr/day, 5 days/week for a total of 11 exposures. Body weight gains in all exposure groups were comparable to controls. 13 references, 13 figures, 9 tables.

Katz, G.V.; Krasavage, W.J.; Terhaar, C.J.

1984-08-01

433

Simultaneous determination of bisphenol A-diglycidyl ether, bisphenol F-diglycidyl ether and their hydrolysis and chlorohydroxy derivatives in canned foods  

Microsoft Academic Search

A new method for the simultaneous determination of bisphenol A-diglycidyl ether (BADGE), bisphenol F-diglycidyl ether (BFDGE)\\u000a and their hydrolysis and chlorohydroxy derivatives in canned foods is presented. Oily and aqueous food samples were extracted\\u000a with tert-butyl methyl ether and acetonitrile, respectively. The compounds in both extracts were determined by using reverse-phase\\u000a gradient high-performance liquid chromatography with fluorescence detection. Optimization of

J. Lintschinger; Walfried Rauter

2000-01-01

434

Ethers from ethanol. 2: Reaction equilibria of simultaneous tert-amyl ethyl ether synthesis and isoamylene isomerization  

SciTech Connect

The recent requirements for blending oxygenates with gasoline for pollution abatement and octane improvement have opened up huge markets for ethers, synthesized by catalytically reacting an isoolefin with an alcohol. Consequently, alternatives to isobutylene-derived methyl tert-butyl ether (MTBE) obtained from methanol and ethyl tert-butyl ether (ETBE) obtained from ethanol are being explored. This paper provides a thermodynamic analysis of the liquid phase etherification of ethanol with 2-methyl-1-butene (2M1B) and 2-methyl-2-butene (2M2B), the two reactive isoamylene isomers. Both these isomers produce tert-amyl ethyl ether (TAEE) but also undergo isomerization. Theoretical and experimental results are provided here for the simultaneous TAEE synthesis and isoamylene isomerization. Expressions for the three thermodynamic equilibrium constants as a function of temperature are developed. Gibbs free energy and the enthalpy of formation of TAEE are also obtained. The equilibrium constants` correlations are utilized to compute the effect of the feed mole ratio of the isoamylenes and the inert solvent to ethanol as well as the reaction temperature on the equilibrium conversions and selectivities. Conditions that maximize etherification conversion and selectivity are explored.

Kitchaiya, P.; Datta, R. [Univ. of Iowa, Iowa City, IA (United States). Dept. of Chemical and Biochemical Engineering

1995-04-01

435

Preparation and performance of polysulfone-sulfonated poly(ether ether ketone) blend ultrafiltration membranes. Part I  

NASA Astrophysics Data System (ADS)

Ultrafiltration membranes were prepared from blends with polysulfone (PSf) and sulfonated poly(ether ether ketone) (SPEEK) by phase inversion technique. The blend membranes were prepared with polymer composition from 0 to15 wt%. Sulfonated poly(ether ether ketone) was used to improve the performance and permeability of blended membranes. The effects of polymer composition on compaction, pure water flux, water content, and membrane hydraulic resistance were studied. The membranes were also subjected to the determination of pore statistics and molecular weight cut-off (MWCO) determination studies by using different molecular weight of proteins. The porosity, pore size of the membranes increased with increasing concentrations of SPEEK in the casting solution. Similarly, the MWCOs of the blend membranes ranged from 20 to 45 kDa, depending on the various polymer blend compositions. The pure water flux of the PSf/SPEEK blend membranes increases from 16.7 to 61.5 l m -2 h, when the concentration of SPEEK increased from 0 to 15 wt%. Scanning electron microscope (SEM) results qualitative evidence for the trends observed for the pore statistics and MWCO studies.

Arthanareeswaran, G.; Mohan, D.; Raajenthiren, M.

2007-08-01

436

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

PubMed Central

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

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

1997-01-01

437

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

438

21 CFR 524.981d - Fluocinolone acetonide, dimethyl sulfoxide solution.  

Code of Federal Regulations, 2010 CFR

...of solution contains 0.01 percent fluocinolone acetonide and 20 percent dimethyl sulfoxide with propylene glycol and citric acid. (b) Sponsor. See No. 000856 in § 510.600(c) of this chapter. (c) Conditions of use....

2010-04-01

439

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

Code of Federal Regulations, 2010 CFR

...of solution contains 0.01 percent of fluocinolone acetonide in 60 percent dimethyl sulfoxide with propylene glycol and citric acid. (b) Sponsor. See No. 000033 in § 510.600(c) of this chapter. (c) Conditions of use. (1)...

2010-04-01

440

Dimethyl fumarate for treatment of multiple sclerosis: mechanism of action, effectiveness, and side effects.  

PubMed

Dimethyl fumarate is an orally available treatment option for relapsing-remitting multiple sclerosis (MS) in a new formulation with improved gastroenteric coating. The mode of action comprises immunomodulatory effects and an activation of nuclear (erythroid-derived 2) related factor mediated antioxidative response pathways leading to additional cytoprotective effects. In two pivotal phase III trials, dimethyl fumarate, 240 mg twice daily, reduced relapse rates by about 50 % as compared with placebo. In the DEFINE trial, progression of disability was also significantly reduced. Both trials demonstrated a significant reduction of gadolinium-enhanced lesions as well as T2 lesions on cranial MRI. The studies revealed a beneficial safety profile of dimethyl fumarate. The most prevalent side effects were transient flushing and gastrointestinal tract irritation. Dimethyl fumarate has recently been approved in the USA for the treatment of relapsing-remitting MS. The compound is a welcome addition to the immunomodulatory treatment armamentarium for MS patients and physicians alike. PMID:24061646

Linker, Ralf A; Gold, Ralf

2013-11-01

441

Determination of Gas-Phase Dimethyl Sulfate and Monomethyl Hydrogen Sulfate.  

National Technical Information Service (NTIS)

Analytical techniques have been developed for the collection and determination of gas phase dimethyl sulfate and monomethyl sulfuric acid in the flue lines and plumes of power plants and in the ambient atmosphere. The techniques involve the collection of ...

L. D. Hansen, V. F. White, D. J. Eatough

1986-01-01

442

Dimethyl carbonate as potential reactant in non-catalytic biodiesel production by supercritical method.  

PubMed

In this study, the non-catalytic supercritical method has been studied in utilizing dimethyl carbonate. It was demonstrated that, the supercritical dimethyl carbonate process without any catalysts applied, converted triglycerides to fatty acid methyl esters with glycerol carbonate and citramalic acid as by-products, while free fatty acids were converted to fatty acid methyl esters with glyoxal. After 12 min of reaction at 350 degrees C/20 MPa, rapeseed oil treated with supercritical dimethyl carbonate reached 94% (w/w) yield of fatty acid methyl ester. The by-products from this process which are glycerol carbonate and citramalic acid are much higher in value than glycerol produced by the conventional process. In addition, the yield of the fatty acid methyl esters as biodiesel was almost at par with supercritical methanol method. Therefore, supercritical dimethyl carbonate process can be a good candidate as an alternative biodiesel production process. PMID:18990561

Ilham, Zul; Saka, Shiro

2009-03-01

443

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

Code of Federal Regulations, 2012 CFR

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

2012-07-01

444

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

Code of Federal Regulations, 2011 CFR

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

2011-07-01

445

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

Code of Federal Regulations, 2010 CFR

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

2010-07-01

446

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

Code of Federal Regulations, 2013 CFR

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

2013-07-01

447

Griseofulvin in Dimethyl Sulfoxide: Penetration into Guinea-Pig Skin and Clinical Findings in Feline Ringworm.  

National Technical Information Service (NTIS)

Topical application of griseofulvin in dimethyl sulfoxide to the unbroken skin of guinea-pigs produced inhibitory concentrations of the antibiotic in subkeratinous tissue. Cats showing a ringworm syndrome caused by Microsporum canis were treated topically...

H. B. Levine, J. M. Cobb, R. H. Fried