Methyl substituted polyimides containing carbonyl and ether connecting groups

NASA Technical Reports Server (NTRS)

Hergenrother, Paul M. (Inventor); Havens, Stephen J. (Inventor)

1992-01-01

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.

Studies on complex π-π and T-stacking features of imidazole and phenyl/p-halophenyl units in series of 5-amino-1-(phenyl/p-halophenyl)imidazole-4-carboxamides and their carbonitrile derivatives: Role of halogens in tuning of conformation

NASA Astrophysics Data System (ADS)

Das, Aniruddha

2017-11-01

5-amino-1-(phenyl/p-halophenyl)imidazole-4-carboxamides (N-phenyl AICA) (2a-e) and 5-amino-1-(phenyl/p-halophenyl)imidazole-4-carbonitriles (N-phenyl AICN) (3a-e) had been synthesized. X-ray crystallographic studies of 2a-e and 3a-e had been performed to identify any distinct change in stacking patterns in their crystal lattice. Single crystal X-ray diffraction studies of 2a-e revealed π-π stack formations with both imidazole and phenyl/p-halophenyl units in anti and syn parallel-displaced (PD)-type dispositions. No π-π stacking of imidazole occurred when the halogen substituent is bromo or iodo; π-π stacking in these cases occurred involving phenyl rings only. The presence of an additional T-stacking had been observed in crystal lattices of 3a-e. Vertical π-π stacking distances in anti-parallel PD-type arrangements as well as T-stacking distances had shown stacking distances short enough to impart stabilization whereas syn-parallel stacking arrangements had got much larger π-π stacking distances to belie any syn-parallel stacking stabilization. DFT studies had been pursued for quantifying the π-π stacking and T-stacking stabilization. The plotted curves for anti-parallel and T-stacked moieties had similarities to the 'Morse potential energy curve for diatomic molecule'. The minima of the curves corresponded to the most stable stacking distances and related energy values indicated stacking stabilization. Similar DFT studies on syn-parallel systems of 2b corresponded to no π-π stacking stabilization at all. Halogen-halogen interactions had also been observed to stabilize the compounds 2d, 2e and 3d. Nano-structural behaviour of the series of compounds 2a-e and 3a-e were thoroughly investigated.

Preparation, IR spectroscopy, and time-of-flight mass spectrometry of halogenated and methylated Si(111)

NASA Astrophysics Data System (ADS)

Salingue, Nils; Hess, Peter

2011-09-01

The preparation of chlorine-, bromine-, and iodine-terminated silicon surfaces (Si(111):Cl, Br, and I) using atomically flat Si(111)-(1×1):H is described. The halogenated surfaces were obtained by photochemically induced radical substitution reactions with the corresponding dihalogen in a Schlenk tube by conventional inert gas chemistry. The nucleophilic substitution of the Si-Cl functionality with the Grignard reagent (CH3MgCl) resulted in the unreconstructed methylated Si(111)-(1×1):CH3 surface. The halogenated and methylated silicon surfaces were characterized by Fourier transform infrared (FTIR) spectroscopy and laser-induced desorption of monolayers (LIDOM). Calibration of the desorption temperature via analysis of time-of-flight (TOF) distributions as a function of laser fluence allowed the determination of the originally emitted neutral fragments by TOF mass spectrometry using electron-impact ionization. The halogens were desorbed atomically and as SiX n (X = Cl, Br) clusters. The methyl groups mainly desorbed as methyl and ethyl fragments and a small amount of +SiCH3.

29 CFR 1926.1106 - Methyl chloromethyl ether.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Toxic and Hazardous Substances § 1926.1106 Methyl chloromethyl ether. Note: The requirements applicable to construction work under this...

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

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

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 chemicalmore » 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.« less

29 CFR 1910.1006 - Methyl chloromethyl ether.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 29 Labor 6 2011-07-01 2011-07-01 false Methyl chloromethyl ether. 1910.1006 Section 1910.1006 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) OCCUPATIONAL SAFETY AND HEALTH STANDARDS (CONTINUED) Toxic and Hazardous...

Methyl N-phenyl carbamate synthesis from aniline and methyl formate: carbon recycling to chemical products.

PubMed

Yalfani, Mohammad S; Lolli, Giulio; Müller, Thomas E; Wolf, Aurel; Mleczko, Leslaw

2015-02-01

Methyl N-phenyl carbamate was synthesized from aniline by using methyl formate as a green and efficient carbonylating agent. High yields were obtained at milder reaction conditions compared to the conventional CO/CH3 OH route. Studies on the reaction sequence led to suggest an alternative and more efficient route to the carbamate via formanilide as intermediate. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

29 CFR 1910.1006 - Methyl chloromethyl ether.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 29 Labor 6 2014-07-01 2013-07-01 true Methyl chloromethyl ether. 1910.1006 Section 1910.1006 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) OCCUPATIONAL SAFETY AND HEALTH STANDARDS (CONTINUED) Toxic and Hazardous Substances § 1910.1006...

Mechanism of Action of the Diphenyl Ether Herbicide Acifluorfen-Methyl in Excised Cucumber (Cucumis sativus L.) Cotyledons 1

PubMed Central

Orr, Gregory L.; Hess, F. Dana

1982-01-01

Cucumber (Cucumis sativus L.) cotyledons were sensitive to the diphenyl ether herbicide acifluorfen-methyl (AFM); methyl 5-[2-chloro-4-(trifluoro-methyl)phenoxyl-2-nitrobenzoate. Injury was detected by monitoring the efflux of 86Rb+ from treated tissues after exposure to light (600 micro einsteins per meter2 per second; photosynthetically active radiation). AFM exhibited activity in green and etiolated tissues in the presence of both 1 micromolar 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU) and 1 micromolar 2,5-dibromo-3-methyl-6-isopropyl-p-benzoquinone (DBMIB), inhibitors of photosynthetic electron transport. Protection against injury could be obtained by pretreating the seedlings with a carotenoid biosynthesis inhibitor, 10 micromolar fluridone {1-methyl-3-phenyl-5-[3-(trifluoromethyl)phenyl]-4 (H)-pyridinone}. After a 4-hour dark pretreatment with 1 and 10 micromolar AFM, cotyledons were exposed to light (600 micro einsteins per meter2 per second; photosynthetically active radiation). Within 1 to 2 hours after light treatment, significant increases in the level of thiobarbituric acid-reacting materials could be detected. Electron microscopic observations of treated tissues revealed significant structural damage to the chloroplast envelope, tonoplast, and plasma membrane. Etiolated cucumber cotyledons treated with 1 micromolar AFM and exposed to light were less susceptible to injury when maintained in an O2-deficient atmosphere. Protection against injury could be obtained with 50 micromolar α-tocopherol. These results suggest AFM is activated in light by yellow plant pigments and then is involved in the initiation of a free radical chain reaction with polyunsaturated fatty acid moieties of phospholipid molecules making up cellular membranes. The perturbations that follow result in a loss of the membrane's selective permeability characteristics, thereby leading to cellular death. Images PMID:16662237

Thermodynamic properties (enthalpy, bond energy, entropy, and heat capacity) and internal rotor potentials of vinyl alcohol, methyl vinyl ether, and their corresponding radicals.

PubMed

da Silva, Gabriel; Kim, Chol-Han; Bozzelli, Joseph W

2006-06-29

Vinyl alcohols (enols) have been discovered as important intermediates and products in the oxidation and combustion of hydrocarbons, while methyl vinyl ethers are also thought to occur as important combustion intermediates. Vinyl alcohol has been detected in interstellar media, while poly(vinyl alcohol) and poly(methyl vinyl ether) are common polymers. The thermochemical property data on these vinyl alcohols and methyl vinyl ethers is important for understanding their stability, reaction paths, and kinetics in atmospheric and thermal hydrocarbon-oxygen systems. Enthalpies , entropies , and heat capacities (C(p)()(T)) are determined for CH(2)=CHOH, C(*)H=CHOH, CH(2)=C(*)OH, CH(2)=CHOCH(3), C(*)H=CHOCH(3), CH(2)=C(*)OCH(3), and CH(2)=CHOC(*)H(2). Molecular structures, vibrational frequencies, , and C(p)(T) are calculated at the B3LYP/6-31G(d,p) density functional calculation level. Enthalpies are also determined using the composite CBS-Q, CBS-APNO, and G3 methods using isodesmic work reactions to minimize calculation errors. Potential barriers for internal rotors are calculated at the B3LYP/6-31G(d,p) level and used to determine the hindered internal rotational contributions to entropy and heat capacity. The recommended ideal gas phase values calculated in this study are the following (in kcal mol(-1)): -30.0, -28.9 (syn, anti) for CH(2)=CHOH; -25.6, -23.9 for CH(2)=CHOCH(3); 31.3, 33.5 for C(*)H=CHOH; 27.1 for anti-CH(2)=C(*)OH; 35.6, 39.3 for C(*)H=CHOCH(3); 33.5, 32.2 for CH(2)=C(*)OCH(3); 21.3, 22.0 for CH(2)=CHOC(*)H(2). Bond dissociation energies (BDEs) and group additivity contributions are also determined. The BDEs reveal that the O-H, O-CH(3), C-OH, and C-OCH(3) bonds in vinyl alcohol and methyl vinyl ether are similar in energy to those in the aromatic molecules phenol and methyl phenyl ether, being on average around 3 kcal mol(-1) weaker in the vinyl systems. The keto-enol tautomerization enthalpy for the interconversion of vinyl alcohol to acetaldehyde is

Aquatic Life Criteria - Methyl Tertiary-Butyl Ether (MTBE)

EPA Pesticide Factsheets

Information pertaining to the 1999 Acute and Chronic Ambient Aquatic Life Water Quality Criteria for Methyl Tertiary-Butyl Ether (MTBE) for freshwater and salt water. Information includes the safe levels of MTBE that should protect the majority of species.

Synthesis of 3-Methyl-4-(4-methylbenzoyl)-1-phenyl-pyrazol-5-One: How to Avoid O-Acylation

ERIC Educational Resources Information Center

Kurteva, Vanya B.; Petrova, Maria A.

2015-01-01

In this laboratory experiment, students synthesize 3-methyl-4-(4-methylbenzoyl)-1-phenyl-pyrazol-5-one by selective C-acylation of 3-methyl-1-phenyl-1H-pyrazol-5-one. Calcium hydroxide is used to push the tautomeric equilibrium toward the enol form, to protect the hydroxyl functionality as a complex, to trap the liberated hydrogen chloride, and to…

Rotational Spectra of Halogenated Ethers Used as Volatile Anaesthetics

NASA Astrophysics Data System (ADS)

Vega-Toribio, Alicia; Lesarri, Alberto; Suenram, Richard D.; Grabow, Jens-Uwe

2009-06-01

Following previous microwave investigations by Suenram et al., we will report on the rotational spectrum of several halogenated ethers used as volatile anaesthetics, including sevoflurane ((CF_3)_2CH-O-CH_2F), isoflurane (CF_3CHCl-O-CHF_2), enflurane (CHFClCF_2-O-CHF_2) and methoxyflurane (CHCl_2CF_2-O-CH_3). This study has been conducted in the 6-18 GHz centimetre-wave region using Balle-Flygare-type FT-microwave spectroscopy. The results will include the analysis of the rotational spectra of minor species in natural abundance (^{13}C and ^{18}O in some cases), structural calculations and auxiliary ab initio modelling. The conformational and structural conclusions will be compared with previous gas-phase electron diffraction and solid-state X-ray diffraction analysis. R. D. Suenram, D. J. Brugh, F. J. Lovas and C. Chu, 51st OSU Int. Symp. On Mol. Spectrosc., Columbus, OH, 1999, RB07

The Chirped-Pulse Fourier Transform Microwave Cp-Ftmw Spectrum and Potential Energy Calculations for AN Aromatic Claisen Rearrangement Molecule, Allyl Phenyl Ether

NASA Astrophysics Data System (ADS)

Grubbs, G. S. Grubbs, Ii; Cooke, S. A.; Novick, Stewart E.

2012-06-01

Claisen rearrangement ethers are a fundamental organic, pericyclic rearrangement reaction reagent. In the mechanism of a Claisen rearrangement, a vinyl allyl ether is needed to provide the necessary Lewis acid/base sites on the molecule for the rearrangement and are simply heated. This rearrangement was first discovered by heating up the title molecule, allyl phenyl ether. However, much like the Diels-Alder, Cope, and other pericyclic reactions, conformation and coordination of chemical groups is key to the Claisen mechanism. In this study, the authors present some structural characteristics of allyl phenyl ether from an analysis of the microwave spectra in the 8-14 GHz region using a CP-FTMW spectrometer. This is, to the authors knowledge, the first known microwave region study of the title molecule. Three conformers have been observed and assigned to date and will be discussed. Along with the rotational spectra, geometry calculations and potential energy surfaces performed at the MP2/6-311G++(3d,2p) level will be discussed and compared to the experimental results. Modeling the Claisen aromatic rearrangement mechanism using CP-FTMW spectroscopy will also be discussed. L. Claisen Chemische Berichte 45, 3157, October 1912.

Identification of [4-[4-(methylsulfonyl)phenyl]-6-(trifluoromethyl)-2-pyrimidinyl] amines and ethers as potent and selective cyclooxygenase-2 inhibitors.

PubMed

Swarbrick, Martin E; Beswick, Paul J; Gleave, Robert J; Green, Richard H; Bingham, Sharon; Bountra, Chas; Carter, Malcolm C; Chambers, Laura J; Chessell, Iain P; Clayton, Nick M; Collins, Sue D; Corfield, John A; Hartley, C David; Kleanthous, Savvas; Lambeth, Paul F; Lucas, Fiona S; Mathews, Neil; Naylor, Alan; Page, Lee W; Payne, Jeremy J; Pegg, Neil A; Price, Helen S; Skidmore, John; Stevens, Alexander J; Stocker, Richard; Stratton, Sharon C; Stuart, Alastair J; Wiseman, Joanne O

2009-08-01

A novel series of [4-[4-(methylsulfonyl)phenyl]-6-(trifluoromethyl)-2-pyrimidine-based cyclooxygenase-2 (COX-2) inhibitors, which have a different arrangement of substituents compared to the more common 1,2-diarylheterocycle based molecules, have been discovered. For example, 2-(butyloxy)-4-[4-(methylsulfonyl)phenyl]-6-(trifluoromethyl)pyrimidine (47), a member of the 2-pyrimidinyl ether series, has been shown to be a potent and selective inhibitor with a favourable pharmacokinetic profile, high brain penetration and good efficacy in rat models of hypersensitivity.

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

USGS Publications Warehouse

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

1997-01-01

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

NIOSH Manual of Analytical Methods (third edition). Fourth supplement

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1990-08-15

The NIOSH Manual of Analytical Methods, 3rd edition, was updated for the following chemicals: allyl-glycidyl-ether, 2-aminopyridine, aspartame, bromine, chlorine, n-butylamine, n-butyl-glycidyl-ether, carbon-dioxide, carbon-monoxide, chlorinated-camphene, chloroacetaldehyde, p-chlorophenol, crotonaldehyde, 1,1-dimethylhydrazine, dinitro-o-cresol, ethyl-acetate, ethyl-formate, ethylenimine, sodium-fluoride, hydrogen-fluoride, cryolite, sodium-hexafluoroaluminate, formic-acid, hexachlorobutadiene, hydrogen-cyanide, hydrogen-sulfide, isopropyl-acetate, isopropyl-ether, isopropyl-glycidyl-ether, lead, lead-oxide, maleic-anhydride, methyl-acetate, methyl-acrylate, methyl-tert-butyl ether, methyl-cellosolve-acetate, methylcyclohexanol, 4,4'-methylenedianiline, monomethylaniline, monomethylhydrazine, nitric-oxide, p-nitroaniline, phenyl-ether, phenyl-ether-biphenyl mixture, phenyl-glycidyl-ether, phenylhydrazine, phosphine, ronnel, sulfuryl-fluoride, talc, tributyl-phosphate, 1,1,2-trichloro-1,2,2-trifluoroethane, trimellitic-anhydride, triorthocresyl-phosphate, triphenyl-phosphate, and vinyl-acetate.

Crystal structure of fac-[2-(4-methyl-5-phenyl-pyridin-2-yl)phenyl-κ2C1,N]bis-[2-(pyridin-2-yl)phenyl-κ2C1,N]iridium(III).

PubMed

Lee, Chi-Heon; Moon, Suk-Hee; Park, Ki-Min; Kang, Youngjin

2016-12-01

In the title compound, [Ir(C 11 H 8 N) 2 (C 18 H 14 N)], the Ir III ion adopts a distorted octa-hedral coordination environment defined by three C , N -chelating ligands, one stemming from a 2-(4-phenyl-5-methyl-pyridin-2-yl)phenyl ligand and two from 2-(pyridin-2-yl)phenyl ligands, arranged in a facial manner. The Ir III ion lies almost in the equatorial plane [deviation = 0.0069 (15) Å]. In the crystal, inter-molecular π-π stacking inter-actions, as well as inter-molecular C-H⋯π inter-actions, are present, leading to a three-dimensional network.

Magnesium Bisamide-Mediated Halogen Dance of Bromothiophenes.

PubMed

Yamane, Yoshiki; Sunahara, Kazuhiro; Okano, Kentaro; Mori, Atsunori

2018-03-16

A magnesium bisamide-mediated halogen dance of bromothiophenes is described. The thienylmagnesium species generated in situ is more stable than the corresponding thienyllithium species, which was applied to trap the transient anion species with several electrophiles, such as allyl iodide, phenyl isocyanate, and tributylstannyl chloride. The utility of the magnesium bisamide-mediated halogen dance is useful in the concise synthesis of a medicinally advantageous compound via a one-pot, ester-directed halogen dance/Negishi cross coupling.

Palladium-Catalyzed Reductive Insertion of Alcohols into Aryl Ether Bonds

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Meng; Gutiérrez, Oliver Y.; Camaioni, Donald M.

Pd/C catalyzes C-O bond cleavage of aryl ethers (diphenyl ether and cyclohexyl phenyl ether) by methanol in H2. The aromatic C-O bond is cleaved by reductive methanolysis, which is initiated by Pd-catalyzed partial hydrogenation of one phenyl ring to form an enol ether. The enol ether reacts rapidly with methanol to form a ketal, which generates methoxycyclohexene by eliminating phenol or an alkanol. Subsequent hydrogenation leads to methoxycyclohexane.

TREATMENT OF METHYL TERT-BUTYL ETHER CONTAMINATED WATER USING PHOTOCATALYSIS

EPA Science Inventory

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

REFINED PBPK MODEL OF AGGREGATE EXPOSURE TO METHYL TERTIARY-BUTYL ETHER

EPA Science Inventory

Aggregate (multiple pathway) exposures to methyl tertiary-butyl ether (MTBE) in air and water occur via dermal, inhalation, and oral routes. Previously, physiologically-based pharmacokinetic (PBPK) models have been used to quantify the kinetic behavior of MTBE and its primary met...

40 CFR 721.10556 - Poly(oxy-1,2-ethanediyl), .alpha.- (2-methyl-2-propen-1-yl) -.omega.-hydroxy-,C12-15-alkyl ethers.

Code of Federal Regulations, 2013 CFR

2013-07-01

....- (2-methyl-2-propen-1-yl) -.omega.-hydroxy-,C12-16-alkyl ethers (PMN P-06-452; CAS No. 675869-05-3...-methyl-2-propen-1-yl) -.omega.-hydroxy-,C12-15-alkyl ethers. 721.10556 Section 721.10556 Protection of...-ethanediyl), .alpha.- (2-methyl-2-propen-1-yl) -.omega.-hydroxy-,C12-15-alkyl ethers. (a) Chemical substance...

40 CFR 721.10556 - Poly(oxy-1,2-ethanediyl), .alpha.- (2-methyl-2-propen-1-yl) -.omega.-hydroxy-,C12-15-alkyl ethers.

Code of Federal Regulations, 2014 CFR

2014-07-01

....- (2-methyl-2-propen-1-yl) -.omega.-hydroxy-,C12-16-alkyl ethers (PMN P-06-452; CAS No. 675869-05-3...-methyl-2-propen-1-yl) -.omega.-hydroxy-,C12-15-alkyl ethers. 721.10556 Section 721.10556 Protection of...-ethanediyl), .alpha.- (2-methyl-2-propen-1-yl) -.omega.-hydroxy-,C12-15-alkyl ethers. (a) Chemical substance...

40 CFR 721.10558 - Poly(oxy-1,2-ethanediyl), .alpha.- (2-methyl-2-propen-1-yl) -.omega.-hydroxy-,C12-16-alkyl ethers.

Code of Federal Regulations, 2013 CFR

2013-07-01

....- (2-methyl-2-propen-1-yl) -.omega.-hydroxy-,C12-16-alkyl ethers (PMN P-06-452; CAS No. 675869-05-3...-methyl-2-propen-1-yl) -.omega.-hydroxy-,C12-16-alkyl ethers. 721.10558 Section 721.10558 Protection of...-ethanediyl), .alpha.- (2-methyl-2-propen-1-yl) -.omega.-hydroxy-,C12-16-alkyl ethers. (a) Chemical substance...

40 CFR 721.10557 - Poly(oxy-1,2-ethanediyl), .alpha.- (2-methyl-2-propen-1-yl) -.omega.-hydroxy-,C10-16-alkyl ethers.

Code of Federal Regulations, 2014 CFR

2014-07-01

....- (2-methyl-2-propen-1-yl) -.omega.-hydroxy-,C12-16-alkyl ethers (PMN P-06-452; CAS No. 675869-05-3...-methyl-2-propen-1-yl) -.omega.-hydroxy-,C10-16-alkyl ethers. 721.10557 Section 721.10557 Protection of...-ethanediyl), .alpha.- (2-methyl-2-propen-1-yl) -.omega.-hydroxy-,C10-16-alkyl ethers. (a) Chemical substance...

40 CFR 721.10558 - Poly(oxy-1,2-ethanediyl), .alpha.- (2-methyl-2-propen-1-yl) -.omega.-hydroxy-,C12-16-alkyl ethers.

Code of Federal Regulations, 2014 CFR

2014-07-01

....- (2-methyl-2-propen-1-yl) -.omega.-hydroxy-,C12-16-alkyl ethers (PMN P-06-452; CAS No. 675869-05-3...-methyl-2-propen-1-yl) -.omega.-hydroxy-,C12-16-alkyl ethers. 721.10558 Section 721.10558 Protection of...-ethanediyl), .alpha.- (2-methyl-2-propen-1-yl) -.omega.-hydroxy-,C12-16-alkyl ethers. (a) Chemical substance...

40 CFR 721.10557 - Poly(oxy-1,2-ethanediyl), .alpha.- (2-methyl-2-propen-1-yl) -.omega.-hydroxy-,C10-16-alkyl ethers.

Code of Federal Regulations, 2013 CFR

2013-07-01

....- (2-methyl-2-propen-1-yl) -.omega.-hydroxy-,C12-16-alkyl ethers (PMN P-06-452; CAS No. 675869-05-3...-methyl-2-propen-1-yl) -.omega.-hydroxy-,C10-16-alkyl ethers. 721.10557 Section 721.10557 Protection of...-ethanediyl), .alpha.- (2-methyl-2-propen-1-yl) -.omega.-hydroxy-,C10-16-alkyl ethers. (a) Chemical substance...

Effect of substrate interaction on the degradation of methyl tert-butyl ether, benzene, toluene, ethylbenzene, and xylene by Rhodococcus sp.

PubMed

Lee, Eun-Hee; Cho, Kyung-Suk

2009-08-15

It was examined the substrate interactions of benzene (B), tolulene (T), ethylbenzene (E), xylene (X), and methyl tert-butyl ether (M) in binary, ternary, quaternary, and quinary mixtures by Rhodococcus sp. EH831 that could aerobically degrade all of five single components. The specific degradation rates (SDRs) of B, T, E, X, and M were 234, 913, 131, 184 and 139 micromol g-dry cell weight (DCW)(-1)h(-1), respectively. In binary, ternary, quaternary, and quinary mixtures of them, ethylbenzene was the strongest inhibitor for the other substrates, and methyl tert-butyl ether was the weakest inhibitor. Interestingly, no degradation of benzene and methyl tert-butyl ether was found in the coexistence of ethylbenzene. The degradation of benzene followed only after toluene became exhausted when both was present. Ethylbenzene was least inhibited by methyl tert-butyl ether and most inhibited by toluene.

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

EPA Science Inventory

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

(Z)-3-Methyl-4-[1-(4-methyl­anilino)propyl­idene]-1-phenyl-1H-pyrazol-5(4H)-one

PubMed Central

Sharma, Naresh; Vyas, Komal M.; Jadeja, R. N.; Kant, Rajni; Gupta, Vivek K.

2013-01-01

In the title mol­ecule, C20H21N3O, the central pyrazole ring forms dihedral angles of 4.75 (9) and 49.11 (9)°, respectively, with the phenyl and methyl-substituted benzene rings. The dihedral angle between the phenyl and benzene rings is 51.76 (8)°. The amino group and carbonyl O atom are involved in an intra­molecular N—H⋯O hydrogen bond. In the crystal, π–π inter­actions are observed between benzene rings [centroid–centroid seperation = 3.892 (2) Å] and pyrazole rings [centroid–centroid seperation = 3.626 (2) Å], forming chains along [111]. The H atoms of the methyl group on the p-tolyl substituent were refined as disordered over two sets of sites in a 0.60 (4):0.40 (4) ratio. PMID:24109353

The Ether-Cleaving Methyltransferase System of the Strict Anaerobe Acetobacterium dehalogenans: Analysis and Expression of the Encoding Genes▿

PubMed Central

Schilhabel, Anke; Studenik, Sandra; Vödisch, Martin; Kreher, Sandra; Schlott, Bernhard; Pierik, Antonio Y.; Diekert, Gabriele

2009-01-01

Anaerobic O-demethylases are inducible multicomponent enzymes which mediate the cleavage of the ether bond of phenyl methyl ethers and the transfer of the methyl group to tetrahydrofolate. The genes of all components (methyltransferases I and II, CP, and activating enzyme [AE]) of the vanillate- and veratrol-O-demethylases of Acetobacterium dehalogenans were sequenced and analyzed. In A. dehalogenans, the genes for methyltransferase I, CP, and methyltransferase II of both O-demethylases are clustered. The single-copy gene for AE is not included in the O-demethylase gene clusters. It was found that AE grouped with COG3894 proteins, the function of which was unknown so far. Genes encoding COG3894 proteins with 20 to 41% amino acid sequence identity with AE are present in numerous genomes of anaerobic microorganisms. Inspection of the domain structure and genetic context of these orthologs predicts that these are also reductive activases for corrinoid enzymes (RACEs), such as carbon monoxide dehydrogenase/acetyl coenzyme A synthases or anaerobic methyltransferases. The genes encoding the O-demethylase components were heterologously expressed with a C-terminal Strep-tag in Escherichia coli, and the recombinant proteins methyltransferase I, CP, and AE were characterized. Gel shift experiments showed that the AE comigrated with the CP. The formation of other protein complexes with the O-demethylase components was not observed under the conditions used. The results point to a strong interaction of the AE with the CP. This is the first report on the functional heterologous expression of acetogenic phenyl methyl ether-cleaving O-demethylases. PMID:19011025

STRUCTURES AND BINDING ENERGIES OF METHYL TERT-BUTYL ETHER-WATER COMPLEXES

EPA Science Inventory

Methyl tert-butyl ether (MTBE) is a well-known environmental contaminant owing to its high solubility in water. Since the early 1990s, MTBE has been added to gasoline to improve air quality in some metropolitan areas of the United States. Improved air quality was, however, achiev...

Quercetin-3-methyl ether inhibits lapatinib-sensitive and -resistant breast cancer cell growth by inducing G2/M arrest and apoptosis

PubMed Central

Li, Jixia; Zhu, Feng; Lubet, Ronald A.; De Luca, Antonella; Grubbs, Clinton; Ericson, Marna E.; D’Alessio, Amelia; Normano, Nicola; Dong, Zigang; Bode, Ann M.

2012-01-01

Lapatinib, an oral, small-molecule, reversible inhibitor of both EGFR and HER2, is highly active in HER2 positive breast cancer as a single agent and in combination with other therapeutics. However, resistance against lapatinib is an unresolved problem in clinical oncology. Recently, interest in the use of natural compounds to prevent or treat cancers has gained increasing interest because of presumed low toxicity. Quercetin-3-methyl ether, a naturally occurring compound present in various plants, has potent anticancer activity. Here, we found that quercetin-3-methyl ether caused in a significant growth inhibition of lapatinib-sensitive and -resistant breast cancer cells. Western blot data showed that quercetin-3-methyl ether had no effect on Akt or ERKs signaling in resistant cells. However, quercetin-3-methyl ether caused a pronounced G2/M block mainly through the Chk1-Cdc25c-cyclin B1/Cdk1 pathway in lapatinib-sensitive and -resistant cells. In contrast, lapatinib produced an accumulation of cells in the G1 phase mediated through cyclin D1, but only in lapatinib-sensitive cells. Moreover, quercetin-3-methyl ether induced significant apoptosis, accompanied with increased levels of cleaved caspase 3, caspase 7 and poly (ADP-ribose) polymerase (PARP) in both cell lines. Overall, these results suggested that quercetin-3-methyl ether might be a novel and promising therapeutic agent in lapatinib-sensitive or -resistant breast cancer patients. PMID:22086611

PHYSIOLOGICALLY BASED PHARMACOKINETIC MODEL FOR HUMAN EXPOSURES TO METHYL TERTIARY-BUTYL ETHER

EPA Science Inventory

Humans can be exposed by inhalation, ingestion, or dermal absorption to methyl tertiary-butyl ether (MTBE), an oxygenated fuel additive, from contaminated water sources. The purpose of this research was to develop a physiologically based pharmacokinetic model describing in human...

INFLUENCE OF METHYL TERT-BUTYL ETHER (MTBE) ON LAKE WATER ALGAE

EPA Science Inventory

Methyl tert-butyl ether (MTBE) has been used as an octane booster in gasoline in the United States since the 1970s. MTBE use increased greatly in the 1990s with the implementation of the Clean Air Act Amendments of 1990. The MTBE enhanced a more complete combustion of fuel hydroc...

The Knock-Limited Performance of Fuel Blends Containing Spiropentane, Methylenecyclobutane, Di-Tert-Butyl Ether, Methyl Tert-Butyl Ether, and Triptane

NASA Technical Reports Server (NTRS)

Meyer, Carl L.

1946-01-01

Tests show that at inlet-air temperatures of 250 deg F and 100 deg F the knock-limited performance of the base fuel of blends, leaded with 4 ml TEL per gallon and containing 20 percent spiropentane, was reduced at fuel/air ratios below 0.085. The 20 percent methylenecyclobutane reduced the knock-limited power of the base fuel at fuel/air ratios below 0.112. Di-tert-butyl ether, methyl-tert-butyl ether, and triptane increased the knock-limited power of the base fuel at all fuel/air ratios and at both temperatures.

Reaction mechanism of dimethyl ether carbonylation to methyl acetate over mordenite – a combined DFT/experimental study

DOE PAGES

Rasmussen, D. B.; Christensen, J. M.; Temel, B.; ...

2017-01-23

The reaction mechanism of dimethyl ether carbonylation to methyl acetate over mordenite was studied theoretically with periodic density functional theory calculations including dispersion forces and experimentally in a fixed bed flow reactor at pressures between 10 and 100 bar, dimethyl ether concentrations in CO between 0.2 and 2.0%, and at a temperature of 438 K. The theoretical study showed that the reaction of CO with surface methyl groups, the rate-limiting step, is faster in the eight-membered side pockets than in the twelve-membered main channel of the zeolite; the subsequent reaction of dimethyl ether with surface acetyl to form methyl acetatemore » was demonstrated to occur with low energy barriers in both the side pockets and in the main channel. Here, the present analysis has thus identified a path, where the entire reaction occurs favourably on a single site within the side pocket, in good agreement with previous experimental studies. The experimental study of the reaction kinetics was consistent with the theoretically derived mechanism and in addition revealed that the methyl acetate product inhibits the reaction – possibly by sterically hindering the attack of CO on the methyl groups in the side pockets.« less

BIODEGRADATION OF METHYL TERT-BUTYL ETHER USING AN INNOVATIVE BIOMASS CONCENTRATOR REACTOR

EPA Science Inventory

The aerobic biodegradation of methyl tert-butyl ether (MTBE) was investigated using a pilot-scale Biomass Concentrator Reactor (BCR). The reactor was operated for a year at a flow rate of 2500 L/d of Cincinnati dechlorinated tap water and an influent MTBE concentration o...

Acid base chemistry of luteolin and its methyl-ether derivatives: A DFT and ab initio investigation

NASA Astrophysics Data System (ADS)

Amat, Anna; De Angelis, Filippo; Sgamellotti, Antonio; Fantacci, Simona

2008-09-01

The acid-base chemistry of luteolin, a flavonoid with important pharmacological and dyeing properties, and of the related methyl ether derivatives have been investigated by DFT and MP2 methods, testing different computational setups. We calculate the pK's of all the possible deprotonation sites, for which no experimental assignment could be achieved. The calculated pK's deliver a different acidity order for the two most acidic deprotonation sites between luteolin and its methyl ether derivatives, due to intramolecular hydrogen bonding in luteolin. A lowest p Ka of 6.19 is computed for luteolin, in good agreement with available experimental data.

40 CFR 721.4098 - Substituted heteroaromatic-2[[4-(dimethylamino) phenyl]azo]-3-methyl-, salts (generic).

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Substituted heteroaromatic-2[[4-(dimethylamino) phenyl]azo]-3-methyl-, salts (generic). 721.4098 Section 721.4098 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for...

Enhanced diisobutene production in the presence of methyl tertiary butyl ether

DOEpatents

Smith, Jr., Lawrence A.

1983-01-01

In the liquid phase reaction of isobutene in the presence of resin cation exchange resins with itself in a C.sub.4 hydrocarbon stream to form dimers, the formation of higher polymers, oligomers, and co-dimer by-products is suppressed by the presence of 0.0001 to 1 mole per mole of isobutene of methyl tertiary butyl ether.

BIODEGRADATION OF METHYL TERT-BUTYL ETHER AND BTEX AT VARYING HYDRAULIC RETENTION TIMES

EPA Science Inventory

The feasibility of biologically degrading methyl tert-butyl ether (MTBE) contaminated groundwater is dependent on the ability to degrade MTBE and its byproducts in the presence of other gasoline contaminants. This study investigates a mixed culture degrading both MTBE and benzene...

REDUCTIVE ACTIVATION OF DIOXYGEN FOR DEGRADATION OF METHYL TERT-BUTYL ETHER BY BIFUNCTION

EPA Science Inventory

Bifunctional aluminum is prepared by sulfating aluminum metal with sulfuric acid. The use of bifunctional aluminum to degrade methyl tert-butyl ether (MTBE) in the presence of dioxygen has been examined using batch systems. Primary degradation products were tert-butyl alcohol, ...

Study of methyl- and phenyl-substituted thermostable polysiloxane-silarylene motionless phases for capillary gas chromatography

NASA Astrophysics Data System (ADS)

Komarova, A. O.; Shashkov, M. V.; Sidel'nikov, V. N.

2017-11-01

Capillary columns based on a number of thermostable polysiloxane-silarylene motionless phases are prepared and their properties are studied. Three polymers with different contents of methyl and phenyl groups are synthesized: dimethylsiloxanesilarylene (DMS), methylphenylsiloxanesilarylene (MPhS), and diphenylsiloxanesilarylene (DPhS). Studies of their thermostability show that the level of the background current of these columns upon heating to 350°C is several times lower than that of a column based on polydimethylsiloxane. Based on McReynolds' studies of polarity and Abraham's studies of the selectivity of prepared columns according to the parameters of intermolecular interactions, it is found that silarylene MLPs are more affected by the contributions from specific interactions (especially for dipole-dipole, π-π-, and n-π-interactions) than MLPs with no phenylene inserts. The effect on the selectivity of a phenyl group inside a chain differs from the one produced by the phenyl groups in side MLP chains. The effect on the selectivity of a phenyl group inside a chain differs from the one produced by the phenyl groups in side MLP chains. Examples of the separation of test mixtures of aromatic and oxygen-containing compounds are obtained, along with an extract of thistle oil containing tocopherols and phytosterols at a final temperature of analysis of 350°C.

Enhanced diisobutene production in the presence of methyl tertiary butyl ether

DOEpatents

Smith, L.A. Jr.

1983-03-01

In the liquid phase reaction of isobutene in the presence of resin cation exchange resins with itself in a C[sub 4] hydrocarbon stream to form dimers, the formation of higher polymers, oligomers, and co-dimer by-products is suppressed by the presence of 0.0001 to 1 mole per mole of isobutene of methyl tertiary butyl ether. 1 fig.

A study of the gamma radiation induced molecular weight changes in poly (phenyl methacrylate), poly (methyl methacrylate) and their copolymers

NASA Astrophysics Data System (ADS)

Hussain, R.; Mohammad, D.

The homopolymers and copolymers of phenyl methacrylate and methyl methacrylate synthesized by free radical polymerization were characterized by infra red and nuclear magnetic resonance spectroscopy. The molecular weight changes produced as a result of gamma irradiation in an argon atmosphere were monitored as a function of dose absorbed by the sample. The radiation induced effects have been discussed in terms of G(Scission), energy absorbed per break and number of bonds broken per gram in a polymer sample. The results reveal that poly (phenyl methacrylate) is more stable than poly (methyl methacrylate) while, the radiation stability of the copolymers depends upon the concentrations of the respective monomers.

Bioconversion of 6-(N-methyl-N-phenyl)aminomethyl androstane steroids by Nocardioides simplex.

PubMed

Sukhodolskaya, Galina; Fokina, Victoria; Shutov, Andrei; Nikolayeva, Vera; Savinova, Tatiana; Grishin, Yuri; Kazantsev, Alexey; Lukashev, Nikolay; Donova, Marina

2017-02-01

The newly synthesized (α/β)-diastereomers of 6-(N-methyl-N-phenyl)aminomethylandrost-4-ene-3,17-dione (5) and 6-(N-methyl-N-phenyl)aminomethylandrost-4-en-17β-ol-3-one (6) were firstly investigated as substrates for the whole cells of Nocardioides simplex VKM Ac-2033D in comparison with their unsubstituted analogs, - androst-4-ene-3,17-dione (1) and androst-4-en-17β-ol-3-one (2). 1(2)-Dehydroderivatives were identified as the major bioconversion products from all the substrates tested. When using the mixtures of (α/β)-stereoisomers of 5 and 6 as the substrates, only β-stereoisomers of the corresponding 1,4-diene-steroids were formed. Along with 1(2)-dehydrogenation, N. simplex VKM Ac-2033D promoted oxidation of the hydroxyl group at C-17 position of 6: both 6(α) and 6(β) were transformed to the corresponding 17-keto derivatives. No steroid core destruction was observed during the conversion of the 6-substituted androstanes 5 and 6, while it was significant when 1 or 2 was used as the substrate. The results suggested high potentials of N. simplex VKM Ac-2033D for the generation of novel 1(2)-dehydroanalogs. Copyright © 2016 Elsevier Inc. All rights reserved.

Mechanisms of catalytic cleavage of benzyl phenyl ether in aqueous and apolar phases

DOE Office of Scientific and Technical Information (OSTI.GOV)

He, Jiayue; Lu, Lu; Zhao, Chen

2014-03-01

Catalytic pathways for the cleavage of ether bonds in benzyl phenyl ether (BPE) in liquid phase using Ni- and zeolite-based catalysts are explored. In the absence of catalysts, the C-O bond is selectively cleaved in water by hydrolysis, forming phenol and benzyl alcohol as intermediates, followed by alkylation. The hydronium ions catalyzing the reactions are provided by the dissociation of water at 523 K. Upon addition of HZSM-5, rates of hydrolysis and alkylation are markedly increased in relation to proton concentrations. In the presence of Ni/SiO 2, the selective hydrogenolysis dominates for cleaving the C aliphatic-O bond. Catalyzed by themore » dual-functional Ni/HZSM-5, hydrogenolysis occurs as the major route rather than hydrolysis (minor route). In apolar undecane, the non-catalytic thermal pyrolysis route dominates. Hydrogenolysis of BPE appears to be the major reaction pathway in undecane in the presence of Ni/SiO 2 or Ni/HZSM-5, almost completely suppressing radical reactions. Density functional theory (DFT) calculations strongly support the proposed C-O bond cleavage mechanisms on BPE in aqueous and apolar phases. These calculations show that BPE is initially protonated and subsequently hydrolyzed in the aqueous phase. Finally, DFT calculations suggest that the radical reactions in non-polar solvents lead to primary benzyl and phenoxy radicals in undecane, which leads to heavier condensation products as long as metals are absent for providing dissociated hydrogen.« less

3-Methyl-4,5-di­hydro­oxazolium tetra­phenyl­borate

PubMed Central

Tiritiris, Ioannis; Saur, Stefan; Kantlehner, Willi

2014-01-01

In the cation of the title salt, C4H8NO+·C24H20B−, the C—N bond lengths are 1.272 (2), 1.4557 (19) and 1.4638 (19) Å, indicating double- and single-bond character, respectively. The C—O bond length of 1.3098 (19) Å shows that double-bond character and charge delocalization occurs within the NCO plane of the cation. In the crystal, a C—H⋯π inter­action is present between the methyl­ene H atom of the cation and one phenyl ring of the tetra­phenyl­borate ion. The latter forms an aromatic pocket in which the cation is embedded. PMID:24765023

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

USGS Publications Warehouse

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

2004-01-01

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

Crystal structure of {2,6-bis-[(di-methyl-amino)-meth-yl]phenyl-κ3N,C1,N'}(bromido/chlorido)-mercury(II).

PubMed

Gupta, Anand; Singh, Harkesh B; Butcher, Ray J

2017-11-01

In the mol-ecular structure of the title compound, {2,6-bis-[(di-methyl-amino)-meth-yl]phenyl-κ 3 N , C 1 , N '}[bromido/chlorido-(0.30/0.70)]mercury(II)-{2,6-bis-[(di-methyl-amino)-meth-yl]phenyl-κ 3 N , C 1 , N '}[bromido/chlorido-(0.24/0.76)]mer-cury(II) (1/1), [HgBr 0.30 Cl 0.70 (C 12 H 19 N 2 )]·[HgBr 0.24 Cl 0.76 (C 12 H 19 N 2 )], there are two mol-ecules in the asymmetric unit of formula L Hg X { L = 2,6-bis-[(di-methyl-amino)-meth-yl]phenyl and X = Cl/Br}. In each mol-ecule, the halide site is mixed Cl/Br, with occupancies of 0.699 (7):0.301 (7) and 0.763 (7):0.237 (7), respectively. The two mol-ecules are linked into dimers by a combination of Hg⋯Hg [Hg⋯Hg = 3.6153 (3) Å] and C-H⋯Cl and C-H⋯π inter-actions.

Geissoschizine methyl ether, a corynanthean-type indole alkaloid from Uncaria rhynchophylla as a potential acetylcholinesterase inhibitor.

PubMed

Yang, Zhong-Duo; Duan, Dong-Zhu; Du, Juan; Yang, Ming-Jun; Li, Shuo; Yao, Xiao-Jun

2012-01-01

Geissoschizine methyl ether (1), a newly discovered strong acetylcholinesterase (AChE) inhibitor, along with six weakly active alkaloids, vallesiachotamine (2), hisuteine (3), hirsutine (4), isorhynchophylline (5), cisocorynoxeine (6) and corynoxeine (7) have been isolated from Uncaria rhynchophylla. Geissoschizine methyl ether (1) inhibited 50% of AChE activity at concentrations of 3.7 ± 0.3 µg mL(-1) while the IC(50) value of physostigmine as a standard was 0.013 ± 0.002 µg mL(-1). The mode of AChE inhibition by 1 was reversible and non-competitive. In addition, molecular modelling was performed to explore the binding mode of inhibitor 1 at the active site of AChE.

DERMAL, ORAL, AND INHALATION PHARMACOKINETICS OF METHYL TERTIARY BUTYL ETHER (MTBE) IN HUMAN VOLUNTEERS

EPA Science Inventory

Methyl tertiary butyl ether (MTBE), a gasoline additive, used to increase octane and reduce carbon monoxide emissions and ozone precursors has contaminated drinking water leading to exposure by oral, inhalation, and dermal routes. To determine its dermal, oral, and inhalation ki...

[Desflurane (I 653) and sevoflurane: halogenated anesthetics of the future?].

PubMed

Debaene, B; Lienhart, A

1992-01-01

Sevoflurane is an halogenated methyl isopropyl ether. It is potent, non explosive and non flammable. It reacts with soda lime to form traces of a related ether which has not been shown to have any toxic effect on animals chronically exposed to it in a closed system. Induction of anaesthesia with sevoflurane is rapid and smooth, as predicted by a blood/gas partition coefficient of about 0.6 and an acceptable odour which allows the use of concentrations of up to 10%. Its MAC has been reported to vary between 1.7 and 2.3 vol %. Sevoflurane causes dose-dependent cardiovascular and respiratory depression. Its effect on the cerebral circulation is similar to that of isoflurane. The extent of biotransformation is similar to that of enflurane, but its low solubility and rapid elimination confine this to the period of inhalation. No toxic effects on the kidneys, liver and haematopoietic system have been found. Desflurane is a fluorinated methyl ether, structurally very similar to isoflurane. It is non flammable and non explosive at clinical concentrations. It is more stable in the presence of soda lime than any of the volatile anaesthetic agents available. This agent must be delivered with a thermostated vaporizer within a closed circle system, as its boiling point is 23.5 degrees C. Desflurane is less potent than isoflurane. Its MAC has been estimated to be about 7.2 vol % in man. Desflurane did not lead to any liver, lung or kidney injury in laboratory rats, even during hypoxia and enzyme induction. Desflurane undergoes little biotransformation, although the presence of volatile metabolites or covalent tissue-bound products cannot be excluded.(ABSTRACT TRUNCATED AT 250 WORDS)

ATTENUATION OF METHYL TERT-BUTYL ETHER IN WATER USING SUNLIGHT AND A PHOTOCATALYST

EPA Science Inventory

The use of methyl tert-butyl ether (MTBE) as a gasoline additive has resulted in increasing pollution of ground water. Most of the conventional treatment technologies are inefficient or costly when the initial concentration of MTBE is low (<200 ug/L). In order to find an eco-frie...

(1-Adamantyl)methyl glycidyl ether: a versatile building block for living polymerization.

PubMed

Moers, Christian; Wrazidlo, Robert; Natalello, Adrian; Netz, Isabelle; Mondeshki, Mihail; Frey, Holger

2014-06-01

(1-Adamantyl)methyl glycidyl ether (AdaGE) is introduced as a versatile monomer for oxyanionic polymerization, enabling controlled incorporation of adamantyl moieties in aliphatic polyethers. Via copolymerization with ethoxyethyl glycidyl ether (EEGE) and subsequent cleavage of the acetal protection groups of EEGE, hydrophilic linear polyglycerols with an adjustable amount of pendant adamantyl moieties are obtained. The adamantyl unit permits control over thermal properties and solubility profile of these polymers (LCST). Additionally, AdaGE is utilized as a termination agent in carbanionic polymerization, affording adamantyl-terminated polymers. Using these structures as macroinitiators for the polymerization of ethylene oxide affords amphiphilic, in-chain adamantyl-functionalized block copolymers. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

DERMAL, ORAL AND INHALATION PHARMACOKINETICS OF METHYL TERTIARY-BUTYL ETHER (MTBE) IN HUMAN VOLUNTEERS

EPA Science Inventory

Methyl tertiary butyl ether (MTBE), a gasoline additive used to increase octane and reduce carbon monoxide emissions and ozone precursors, has contaminated drinking water and can lead to exposure by oral, inhalation, and dermal routes. To determine its dermal, oral, and inhal...

Polystyrene bound oxidovanadium(IV) and dioxidovanadium(V) complexes of histamine derived ligand for the oxidation of methyl phenyl sulfide, diphenyl sulfide and benzoin.

PubMed

Maurya, Mannar R; Arya, Aarti; Kumar, Amit; Pessoa, João Costa

2009-03-28

Ligand Hsal-his (I) derived from salicylaldehyde and histamine has been covalently bound to chloromethylated polystyrene cross-linked with 5% divinylbenzene. Upon treatment with [VO(acac)(2)] in DMF, the polystyrene-bound ligand (abbreviated as PS-Hsal-his, II) gave the stable polystyrene-bound oxidovanadium(iv) complex PS-[V(IV)O(sal-his)(acac)] , which upon oxidation yielded the dioxidovanadium(v) PS-[V(V)O(2)(sal-his)] complex. The corresponding non polymer-bound complexes [V(IV)O(sal-his)(acac)] and [V(V)O(2)(sal-his)] have also been obtained. These complexes have been characterised by IR, electronic, (51)V NMR and EPR spectral studies, and thermal as well as scanning electron micrograph studies. Complexes and have been used as a catalyst for the oxidation of methyl phenyl sulfide, diphenyl sulfide and benzoin with 30% H(2)O(2) as oxidant. Under the optimised reaction conditions, a maximum of 93.8% conversion of methyl phenyl sulfide with 63.7% selectivity towards methyl phenyl sulfoxide and 36.3% towards methyl phenyl sulfone has been achieved in 2 h with 2 . Under similar conditions, diphenyl sulfide gave 83.4% conversion where selectivity of reaction products varied in the order: diphenyl sulfoxide (71.8%) > diphenyl sulfone (28.2%). A maximum of 91.2% conversion of benzoin has been achieved within 6 h, and the selectivities of reaction products are: methylbenzoate (37.0%) > benzil (30.5%) > benzaldehyde-dimethylacetal (22.5%) > benzoic acid (8.1%). The PS-bound complex, 1 exhibits very comparable catalytic potential. These polymer-anchored heterogeneous catalysts do not leach during catalytic action, are recyclable and show higher catalytic activity and turnover frequency than the corresponding non polymer-bound complexes. EPR and (51)V NMR spectroscopy was used to characterise methanolic solutions of 3 and 4 and to identify species formed upon addition of H(2)O(2) and/or acid and/or methyl phenyl sulfide.

40 CFR 413.02 - General definitions.

Code of Federal Regulations, 2013 CFR

2013-07-01

...-bromophenyl phenyl ether Bis (2-chloroisopropyl) ether Bis (2-chloroethoxy) methane Methylene chloride (dichloromethane) Methyl chloride (chloromethane) Methyl bromide (bromomethane) Bromoform (tribromomethane...-phenylene pyrene) Pyrene Tetrachloroethylene Toluene Trichloroethylene Vinyl chloride (chloroethylene...

Base-Pairing Energies of Proton-Bound Dimers and Proton Affinities of 1-Methyl-5-Halocytosines: Implications for the Effects of Halogenation on the Stability of the DNA i-Motif

NASA Astrophysics Data System (ADS)

Yang, Bo; Wu, R. R.; Rodgers, M. T.

2015-09-01

(CCG)n•(CGG)n trinucleotide repeats have been found to be associated with fragile X syndrome, the most widespread inherited cause of mental retardation in humans. The (CCG)n•(CGG)n repeats adopt i-motif conformations that are preferentially stabilized by base-pairing interactions of noncanonical proton-bound dimers of cytosine (C+•C). Halogenated cytosine residues are one form of DNA damage that may be important in altering the structure and stability of DNA or DNA-protein interactions and, hence, regulate gene expression. Previously, we investigated the effects of 5-halogenation and 1-methylation of cytosine on the base-pairing energies (BPEs) using threshold collision-induced dissociation (TCID) techniques. In the present study, we extend our work to include proton-bound homo- and heterodimers of cytosine, 1-methyl-5-fluorocytosine, and 1-methyl-5-bromocytosine. All modifications examined here are found to produce a decrease in the BPEs. However, the BPEs of all of the proton-bound dimers examined significantly exceed those of Watson-Crick G•C, neutral C•C base pairs, and various methylated variants such that DNA i-motif conformations should still be preserved in the presence of these modifications. The proton affinities (PAs) of the halogenated cytosines are also obtained from the experimental data by competitive analysis of the primary dissociation pathways that occur in parallel for the proton-bound heterodimers. 5-Halogenation leads to a decrease in the N3 PA of cytosine, whereas 1-methylation leads to an increase in the N3 PA. Thus, the 1-methyl-5-halocytosines exhibit PAs that are intermediate.

The Synthesis of Phenyl Acetylene Phenols for Development of New Explosives

NASA Astrophysics Data System (ADS)

Chikhradze, Nikoloz; Nadirashvili, Merab; Khomeriki, Sergo; Varshanidze, Iasha

2017-12-01

The purpose of this research is to produce derivatives of simple phenols as “raw material” for the synthesis of new phenolic explosives. A big number of valuable products is synthesized from phenol and its homologues including well-known explosives - picric acid, methyl picrate, cresolite, etc. In general, a structural modification of well-known explosives’ molecules is the most important among the methods for the synthesis of new explosives. This method can be used in certain modifications. For example, the synthesis of methyl picrate is possible not only to replace picric acid’s hydroxyl with metoxyl, but with nitration of anisole as well, i. e, by the reciprocating synthesis. Thus, to produce the new analogues of well-known phenolic explosives, the preliminary modification of simple phenols’ molecules and further nitration, presumably by a formation of dinitro derivatives may be performed. The alkylation of phenol, anisole and m - cresol by the secondary phenyl acetylene alcohols in the presence of concentrated phosphoric acid was carried out. Para-substituted alkynyl phenols with high yields were developed. The chemical transformations were carried out by a participation of their molecules’ active centres. The corresponding ethers, esters and saturated isologues have been synthesized. The article describes the conditions of a synthesis of 14 new phenyl acetylenes’ substances that may be used as substrates in a nitration reaction.

Methyl 3-[3',4'-(methylenedioxy)phenyl]-2-methyl glycidate: an ecstasy precursor seized in Sydney, Australia.

PubMed

Collins, Michael; Heagney, Aaron; Cordaro, Frank; Odgers, David; Tarrant, Gregory; Stewart, Samantha

2007-07-01

Five 44 gallon drums labeled as glycidyl methacrylate were seized by the Australian Customs Service and the Australian Federal Police at Port Botany, Sydney, Australia, in December 2004. Each drum contained a white, semisolid substance that was initially suspected to be 3,4-methylenedioxymethylamphetamine (MDMA). Gas chromatography-mass spectroscopy (GC/MS) analysis demonstrated that the material was neither glycidyl methacrylate nor MDMA. Because intelligence sources employed by federal agents indicated that this material was in some way connected to MDMA production, suspicion fell on the various MDMA precursor chemicals. Using a number of techniques including proton nuclear magnetic resonance spectroscopy ((1)H NMR), carbon nuclear magnetic resonance spectroscopy ((13)C NMR), GC/MS, infrared spectroscopy, and total synthesis, the unknown substance was eventually identified as methyl 3-[3',4'(methylenedioxy)phenyl]-2-methyl glycidate. The substance was also subjected to a published hydrolysis and decarboxylation procedure and gave a high yield of the MDMA precursor chemical, 3,4-methylenedioxyphenyl-2-propanone, thereby establishing this material as a "precursor to a precursor."

EVALUATION OF METHYL TERT-BUTYL ETHER (MTBE) AS AN INTERFERENCE ON COMMERCIAL BREATH-ALCOHOL ANALYZERS

EPA Science Inventory

Anecdotal reports suggest that high environmental or occupational exposures to the fuel oxygenate methyl tert-butyl ether (MTBE) may result in breath concentrations that are sufficiently elevated to cause a false positive on commercial breath-alcohol analyzers. We evaluated th...

Azidated Ether-Butadiene-Ether Block Copolymers as Binders for Solid Propellants

NASA Astrophysics Data System (ADS)

Cappello, Miriam; Lamia, Pietro; Mura, Claudio; Polacco, Giovanni; Filippi, Sara

2016-07-01

Polymeric binders for solid propellants are usually based on hydroxyl-terminated polybutadiene (HTPB), which does not contribute to the overall energy output. Azidic polyethers represent an interesting alternative but may have poorer mechanical properties. Polybutadiene-polyether copolymers may combine the advantages of both. Four different ether-butadiene-ether triblock copolymers were prepared and azidated starting from halogenated and/or tosylated monomers using HTPB as initiator. The presence of the butadiene block complicates the azidation step and reduces the storage stability of the azidic polymer. Nevertheless, the procedure allows modifying the binder properties by varying the type and lengths of the energetic blocks.

Searching for trans ethyl methyl ether in Orion KL.

PubMed

Tercero, B; Cernicharo, J; López, A; Brouillet, N; Kolesniková, L; Motiyenko, R A; Margulès, L; Alonso, J L; Guillemin, J-C

2015-10-01

We report on the tentative detection of trans ethyl methyl ether (tEME), t-CH 3 CH 2 OCH 3 , through the identification of a large number of rotational lines from each one of the spin states of the molecule towards Orion KL. We also search for gauche-trans-n-propanol, Gt-n-CH 3 CH 2 CH 2 OH, an isomer of tEME in the same source. We have identified lines of both species in the IRAM 30 m line survey and in the ALMA Science Verification data. We have obtained ALMA maps to establish the spatial distribution of these species. Whereas tEME mainly arises from the compact ridge component of Orion, Gt-n-propanol appears at the emission peak of ethanol (south hot core). The derived column densities of these species at the location of their emission peaks are ≤(4.0 ± 0.8) × 10 15 cm -2 and ≤(1.0 ± 0.2)× 10 15 cm -2 for tEME and Gt-n-propanol, respectively. The rotational temperature is ~100 K for both molecules. We also provide maps of CH 3 OCOH, CH 3 CH 2 OCOH, CH 3 OCH 3 , CH 3 OH, and CH 3 CH 2 OH to compare the distribution of these organic saturated O-bearing species containing methyl and ethyl groups in this region. Abundance ratios of related species and upper limits to the abundances of non-detected ethers are provided. We derive an abundance ratio N (CH 3 OCH 3 )/ N (tEME) ≥ 150 in the compact ridge of Orion.

Methyl t-Butyl Ether Mineralization in Surface-Water Sediment Microcosms under Denitrifying Conditions

USGS Publications Warehouse

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

2001-01-01

Mineralization of [U-14C] methyl t-butyl ether (MTBE) to 14CO2 without accumulation of t-butyl alcohol (TBA) was observed in surface-water sediment microcosms under denitrifying conditions. Methanogenic activity and limited transformation of MTBE to TBA were observed in the absence of denitrification. Results indicate that bed sediment microorganisms can effectively degrade MTBE to nontoxic products under denitrifying conditions.

Ab initio study of weakly bound halogen complexes: RX⋯PH3.

PubMed

Georg, Herbert C; Fileti, Eudes E; Malaspina, Thaciana

2013-01-01

Ab initio calculations were employed to study the role of ipso carbon hybridization in halogenated compounds RX (R=methyl, phenyl, acetyl, H and X=F, Cl, Br and I) and its interaction with a phosphorus atom, as occurs in the halogen bonded complex type RX⋯PH3. The analysis was performed using ab initio MP2, MP4 and CCSD(T) methods. Systematic energy analysis found that the interaction energies are in the range -4.14 to -11.92 kJ mol(-1) (at MP2 level without ZPE correction). Effects of electronic correlation levels were evaluated at MP4 and CCSD(T) levels and a reduction of up to 27% in interaction energy obtained in MP2 was observed. Analysis of the electrostatic maps confirms that the PhCl⋯PH3 and all MeX⋯PH3 complexes are unstable. NBO analysis suggested that the charge transfer between the moieties is bigger when using iodine than bromine and chlorine. The electrical properties of these complexes (dipole and polarizability) were determined and the most important observed aspect was the systematic increase at the dipole polarizability, given by the interaction polarizability. This increase is in the range of 0.7-6.7 u.a. (about 3-7%).

Synthesis Of [2h, 13c] And [2h3, 13c]Methyl Aryl Sulfides

DOEpatents

Martinez, Rodolfo A.; Alvarez, Marc A.; Silks, III, Louis A.; Unkefer, Clifford J.

2004-03-30

The present invention is directed to labeled compounds, [.sup.2 H.sub.1, .sup.13 C], [.sup.2 H.sub.2, .sup.13 C] and [.sup.2 H.sub.3, .sup.13 C]methyl aryl sulfides wherein the .sup.13 C methyl group attached to the sulfur of the sulfide includes exactly one, two or three deuterium atoms and the aryl group is selected from the group consisting of 1-naphthyl, substituted 1-naphthyl, 2-naphthyl, substituted 2-naphthyl, and phenyl groups with the structure ##STR1## wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4, and R.sub.5 are each independently, hydrogen, a C.sub.1 -C.sub.4 lower alkyl, a halogen, an amino group from the group consisting of NH.sub.2, NHR and NRR' where R and R' are each a C.sub.1 -C.sub.4 lower alkyl, a phenyl, or an alkoxy group. The present invention is also directed to processes of preparing [.sup.2 H.sub.1, .sup.13 C], [.sup.2 H.sub.2,.sup.13 C] and [.sup.2 H.sub.3, .sup.13 C]methyl aryl sulfides wherein the .sup.13 C methyl group attached to the sulfur of the sulfide includes exactly one, two or three deuterium atoms. The present invention is also directed to the labeled compounds of [.sup.2 H.sub.1, .sup.13 C]methyl iodide and [.sup.2 H.sub.2, .sup.13 C]methyl iodide.

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

EPA Science Inventory

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

Impact of a heteroatom in a structure-activity relationship study on analogues of phenyl glycidyl ether (PGE) from epoxy resin systems.

PubMed

Niklasson, Ida B; Delaine, Tamara; Luthman, Kristina; Karlberg, Ann-Therese

2011-04-18

Epoxy resins are among the most common causes of occupational contact dermatitis. They are normally used in so-called epoxy resin systems (ERS). These commercial products are combinations of epoxy resins, curing agents, modifiers, and reactive diluents. The most frequently used resins are diglycidyl ethers based on bisphenol A (DGEBA) and bisphenol F (DGEBF). In this study, we have investigated the contact allergenic properties of a series of analogues to the reactive diluent phenyl glycidyl ether (PGE), all with similar basic structures but with varying heteroatoms or with no heteroatom present. The chemical reactivity of the compounds in the test series toward the hexapeptide H-Pro-His-Cys-Lys-Arg-Met-OH was investigated. All epoxides were shown to bind covalently to both cysteine and proline residues. The percent depletion of nonreacted peptide was also studied resulting in ca. 60% depletion when using either PGE, phenyl 2,3-epoxypropyl sulfide (2), or N-(2,3-epoxypropyl)aniline (3), and only 15% when using 1,2-epoxy-4-phenylbutane (4) at the same time point. The skin sensitization potencies of the epoxides using the murine local lymph node assay (LLNA) were evaluated in relation to the observed physicochemical and reactivity properties. To enable determination of statistical significance between structurally closely related compounds, a nonpooled LLNA was performed. It was found that all investigated compounds containing a heteroatom in the α-position to the epoxide were strong sensitizers, congruent with the reactivity data, indicating that the impact of a heteroatom is crucial for the sensitizing capacity for this type of epoxides.

Synthesis of carboxylic acids, esters, alcohols and ethers containing a tetrahydropyran ring derived from 6-methyl-5-hepten-2-one.

PubMed

Hanzawa, Yohko; Hashimoto, Kahoko; Kasashima, Yoshio; Takahashi, Yoshiko; Mino, Takashi; Sakamoto, Masami; Fujita, Tsutomu

2012-01-01

3-hydroxy acids, 3-hydroxy-3,7-dimethyloct-6-enoic acid (1) and 3-hydroxy-2,2,3,7-tetramethyloct-6-enoic acid (2), were prepared from 6-methyl-5-hepten-2-one, and they were subsequently used to prepare (2,6,6-trimethyltetrahydropyran-2-yl)acetic acid (3) and 2-methyl-2-(2,6,6-trimethyltetrahydropyran-2-yl)propanoic acid (4), respectively, via cyclization with an acidic catalyst such as boron trifluoride diethyl etherate or iodine. The reaction of carboxylic acids 3 and 4 with alcohols, including methanol, ethanol, and 1-propanol, produced the corresponding methyl, ethyl, and propyl esters, which all contained a tetrahydropyran ring. Reduction of carboxylic acids 3 and 4 afforded the corresponding alcohols. Subsequent reactions of these alcohols with several acyl chlorides produced novel esters. The alcohols also reacted with methyl iodide and sodium hydride to provide novel ethers. A one-pot cyclization-esterification of 1 to produce esters containing a tetrahydropyran ring, using iodine as a catalyst, was also investigated.

In vitro study comparing the ability of mono-octanoin and mono-octanoin plus methyl tert-butyl ether to dissolve biliary stones.

PubMed

Tritapepe, R; Cesana, B

1996-01-01

This in vitro study compared the gallstone dissolution rates of mono-octanoin, mono-octanoin plus 10% distilled water, and mono-octanoin plus methyl tert-butyl ether 2:1. Sixteen stones were treated with each solvent at a slow perfusion rate of 3-4 ml/h and a rapid perfusion rate of 2.5 ml/30 min with 20-sec instillation/aspiration cycles, both with and without bile. The stones were weighed before, and 3, 6, 12 and 24 hrs after the start of treatment: the solvent was changed every 30 min. After 24 hrs of instillation/aspiration without bile, the mono-octanoin/methyl tert-butyl ether mixture reduced the weight of the stones by 93%, mono-octanoin plus water by 63%, and mono-octanoin alone by 52%; with bile, the figures were, respectively, 86%, 42% and 40%. The mono-octanoin/methyl tert-butyl ether mixture thus took approximately half the time needed by the other two preparations to dissolve the stones to the same extent, a finding which may be relevant for the clinical dissolution of bile duct stones.

Inorganic Halogen Oxidizer Research

DTIC Science & Technology

1975-02-26

K. 0. Christe and C. J. Schack, Advances Inorg. Chem. Radiochem. 15. "The NF * Radical Cation. Esr Studies of Radiation Effects in NF„+ Salts...and 25°) in a wide variety of polar and nonpolar solvents, such as aqueous solutions, alcohols, ketones , esters, ethers , and aromatic and halogenated... Studies of Radiation Effects in NF, Salts = 4 S. P. Mishra, M. C R. Symons, K. 0. Christe, R. D. Wilson and R. I. Wagner Received. . . August .9

40 CFR 721.1800 - 3,3′,5,5′-Tetra-methyl-bi-phenyl-4,4′-diol.

Code of Federal Regulations, 2012 CFR

2012-07-01

... (CONTINUED) TOXIC SUBSTANCES CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.1800 3,3′,5,5′-Tetra-methyl-bi-phenyl-4,4′-diol. (a) Chemical substances and significant new uses subject to reporting. (1) The chemical substance identified as 3,3′,5,5...

40 CFR 721.1800 - 3,3′,5,5′-Tetra-methyl-bi-phenyl-4,4′-diol.

Code of Federal Regulations, 2011 CFR

2011-07-01

... (CONTINUED) TOXIC SUBSTANCES CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.1800 3,3′,5,5′-Tetra-methyl-bi-phenyl-4,4′-diol. (a) Chemical substances and significant new uses subject to reporting. (1) The chemical substance identified as 3,3′,5,5...

40 CFR 721.1800 - 3,3′,5,5′-Tetra-methyl-bi-phenyl-4,4′-diol.

Code of Federal Regulations, 2014 CFR

2014-07-01

... (CONTINUED) TOXIC SUBSTANCES CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.1800 3,3′,5,5′-Tetra-methyl-bi-phenyl-4,4′-diol. (a) Chemical substances and significant new uses subject to reporting. (1) The chemical substance identified as 3,3′,5,5...

40 CFR 721.1800 - 3,3′,5,5′-Tetra-methyl-bi-phenyl-4,4′-diol.

Code of Federal Regulations, 2013 CFR

2013-07-01

... (CONTINUED) TOXIC SUBSTANCES CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.1800 3,3′,5,5′-Tetra-methyl-bi-phenyl-4,4′-diol. (a) Chemical substances and significant new uses subject to reporting. (1) The chemical substance identified as 3,3′,5,5...

40 CFR 721.1800 - 3,3′,5,5′-Tetra-methyl-bi-phenyl-4,4′-diol.

Code of Federal Regulations, 2010 CFR

2010-07-01

... (CONTINUED) TOXIC SUBSTANCES CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.1800 3,3′,5,5′-Tetra-methyl-bi-phenyl-4,4′-diol. (a) Chemical substances and significant new uses subject to reporting. (1) The chemical substance identified as 3,3′,5,5...

Low dielectric fluorinated poly(phenylene ether ketone) film and coating

NASA Technical Reports Server (NTRS)

Cassidy, Patrick E. (Inventor); Tullos, Gordon L. (Inventor); St.clair, Anne K. (Inventor)

1990-01-01

The present invention relates to film and coating materials prepared from novel fluorinated poly(phenylene ether ketones). A fluorinated poly(phenylene ether ketone) is prepared by reacting a bisphenol with 1,1,1,3,3,3 hexafluoro-2,2-bis 4-(4-halobenzoyl) phenyl propane (wherein halo is fluoro or chloro), which is a novel monomer formed as the reaction product of halobenzene (wherein halo is fluoro or chloro) and 1,1,1,3,3,3 hexafluoro-2,2-bis (p-chloro formyl phenyl) propane. Especially beneficial results of this invention are that films and coating materials prepared from the novel fluorinated poly(phenylene ether ketone) are essentially optically transparent/colorless and have a lower dielectric constant than otherwise comparable, commercially available poly(phenylene ether ketones). Moreover, unlike the otherwise comparable commercially available materials, the novel fluorinated poly(phenylene ether ketones) of the present invention can be solution cast or sprayed to produce the films and coatings. Furthermore, the long term thermal stability of the polymers of the present invention is superior to that of the commercially available materials.

REMOVAL OF METHYL T-BUTYL ETHER (MTBE) FROM WATER BY PERVAPORATION: BENCH-SCALE AND PILOT SCALE EVALUATIONS

EPA Science Inventory

The ability of pervaporation to remove methyl t-butyl ether (MTBE) from water was evaluated at bench- and pilot-scales. Process parameters studied included flow rate, temperature, MTBE concentration, membrane module type, and permeate pressure. Pervaporation performance was ass...

DERMAL EXPOSURE TO METHYL TERT-BUTYL ETHER (MTBE) AND DIBROMOCHLOROMETHANE (DBCM) WHILE BATHING WITH CONTAMINATED WATER

EPA Science Inventory

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

WATER QUALITY AT FIVE MARINAS IN LAKE TEXOMA AS RELATED TO METHYL TERT-BUTYL ETHER (MTBE)

EPA Science Inventory

Occurrence of methyl tert-butyl ether (MTBE) in five marinas was monitored between June 1999 and November 2000 in Lake Texoma located on the border of Oklahoma and Texas. MTBE is a commonly used gasoline additive and a suspected carcinogen. Lake water was collected at locations i...

Thermodynamic and Kinetic Behavior of the Polystyrene/Poly(vinyl methyl ether) Blend as Studied by Excimer Fluorescence.

DTIC Science & Technology

1986-01-02

AD-A±63 895 THERMODYNAMIC AND KINETIC BEHAVIOR OF THE / POLYSTYRENE/POLY(YINYL METHYL E..(U) STANFORD UNIY CALIFDEPT OF CHEMICAL ENGINEERING C N...Polystyrene/Poly(vinyl methyl ether) Blend 7. DEcFRMN 81 toOR 30USptE8 00~ as Studied by Excimer Fluorescence 6 EFRIGOG EOTNME *AUTHOR() a. CONTRACT OR GRANT...werea fondoare ihemoriisof * ~ Ex e sp fluodecositionsdu to deud Gen e and hoog Pinus Florsneis shownhase migrationprocSECURITY CLASIFICTIO OFd

Transesterification of propylene glycol methyl ether in chromatographic reactors using anion exchange resin as a catalyst.

PubMed

Oh, Jungmin; Sreedhar, Balamurali; Donaldson, Megan E; Frank, Timothy C; Schultz, Alfred K; Bommarius, Andreas S; Kawajiri, Yoshiaki

2016-09-30

Reactive chromatography using an anion exchange resin is proposed for a transesterification reaction of propylene glycol methyl ether (DOWANOL™ PM) with ethyl acetate to produce propylene glycol methyl ether acetate (DOWANOL™ PMA). This reaction is studied in batch and chromatographic reactors catalyzed by an anion exchange resin. Several anion exchange resins are tested and compared based on the performance of resin as an adsorbent and a catalyst. A chromatographic column is packed with a selected catalyst, AMBERLITE™ IRA904, and both reaction and chromatographic elution are studied at different temperatures and feed concentrations. The resulting chromatograms are fitted to a mathematical model to obtain adsorption equilibrium and reaction kinetic parameters by the inverse method. Compared to esterification investigated in a previous study, transesterification has advantages such as a higher conversion at lower temperature and easy removal of the byproduct which may lead to higher productivity. Deactivation of anion exchange resins is observed and potential solutions are suggested. Copyright © 2016 Elsevier B.V. All rights reserved.

Anaerobic Biodegradation Of Methyl tert-Butyl Ether Under Iron-Reducing Conditions In Batch And Continuous-Flow Cultures

EPA Science Inventory

The feasibility of biodegradation of the fuel oxygenate methyl tert-butyl ether (MTBE) under iron-reducing conditions was explored in batch and continuous-flow systems. A porous pot completely-mixed reactor was seeded with diverse cultures and operated under iron-reducing...

CO-OCCURRENCE OF METHYL- TERT-BUTYL ETHER (MTBE) AND BTEX COMPOUNDS AT MARINAS IN A LARGE RESEVOIR

EPA Science Inventory

Methyl tert-butyl ether (MTBE) is released into the environment as one of some gasoline components, not as a pure compound. BTEX compounds (benzene, tolune, ethylbenzene, and xylenes) are major volatile constituents found in gasoline and are water soluble and mobile. This study...

Gas Phase Conformations and Methyl Internal Rotation for 2-PHENYLETHYL Methyl Ether and its Argon Van Der Waals Complex from Fourier Transform Microwave Spectroscopy

NASA Astrophysics Data System (ADS)

Gurusinghe, Ranil M.; Tubergen, Michael

2015-06-01

A mini-cavity microwave spectrometer was used to record the rotational spectra arising from 2-phenylethyl methyl ether and its weakly bonded argon complex in the frequency range of 10.5 - 22 GHz. Rotational spectra were found for two stable conformations of the monomer: anti-anti and gauche-anti, which are 1.4 kJ mol-1 apart in energy at wB97XD/6-311++G(d,p) level. Doubled rotational transitions, arising from internal motion of the methyl group, were observed for both conformers. The program XIAM was used to fit the rotational constants, centrifugal distortion constants, and barrier to internal rotation to the measured transition frequencies of the A and E internal rotation states. The best global fit values of the rotational constants for the anti-anti conformer are A= 3799.066(3) MHz, B= 577.95180(17) MHz, C= 544.7325(3) MHz and the A state rotational constants of the gauche-anti conformer are A= 2676.1202(7) MHz, B= 760.77250(2) MHz, C= 684.78901(2) MHz. The rotational spectrum of 2-phenylethyl methyl ether - argon complex is consistent with the geometry where argon atom lies above the plane of the benzene moiety of gauche-anti conformer. Tunneling splittings were too small to resolve within experimental accuracy, likely due to an increase in three fold potential barrier when the argon complex is formed. Fitted rotational constants are A= 1061.23373(16) MHz, B= 699.81754(7) MHz, C= 518.33553(7) MHz. The lowest energy solvated ether - water complex with strong intermolecular hydrogen bonding has been identified theoretically. Progress on the assignment of the water complex will also be presented.

Microwave Spectroscopy of Trans-Ethyl Methyl Ether in the Ground State

NASA Astrophysics Data System (ADS)

Kobayashi, Kaori; Sakai, Yusuke; Tsunekawa, Shozo; Miyamoto, Taihei; Fujitake, Masaharu; Ohashi, Nobukimi

2013-06-01

The trans-ethyl methyl ether molecule (CH_3CH_2OCH_3) has two inequivalent methyl group internal rotors which corresponds to the two vibrational motions, ν_{28} and ν_{29}. Due to these internal rotations, a rotational transition could be split into maximum five components. The skeletal torsion (ν_{30}) is another low-lying state (ν_{30}) that interacts with the ν_{28} and ν_{29} modes. The microwave spectra of the trans-ethyl methyl ether molecule in the ν_{28} = 1, ν_{29} = 1, and ν_{30} = 1, 2 and 3 have been extensively studied by using Hougen's tunneling matrix formalism. The microwave spectroscopy in the ground state was studied by several groups. The splitting due to the ν_{28} mode (C-CH_3 internal rotation) is small in the ground state and was not fully resolved in most of the previous studied rotational transitions. In this paper, we report the results of the pulsed nozzle-jet Fourier transform microwave spectroscopy so as to measure the fully resolved spectra. The submillmeter wave spectroscopy was also carried out. Our analysis including the previously reported transitions would be useful for astronomical observations. K. Kobayashi, T. Matsui, N. Mori, S. Tsunekawa, and N. Ohashi J. Mol. Spectrosc. {269}, 242 2011. K. Kobayashi, T. Matsui, S. Tsunekawa, and N. Ohashi J. Mol. Spectrosc. {255}, 164 2009. K. Kobayashi, T. Matsui, N. Mori, S. Tsunekawa, and N. Ohashi J. Mol. Spectrosc.{251}, 301 2008. K. Kobayashi, K. Murata, S. Tsunekawa, and N. Ohashi Int. Symposium on Mol. Spectrosc., 65th Meeting TH15 2010.} M. Hayashi, and K. Kuwada J. Mol. Structure {28}, 147 1975. M. Hayashi, and M. Adachi J. Mol. Structure {78}, 53 1982. S. Tsunekawa, Y. Kinai, Y. Kondo, H. Odashima, and K. Takagi Molecules {8}, 103 2003. U. Fuchs, G. Winnewisser, P. Groner, F. C. De Lucia, and E. Herbst Astrophys. J. Suppl. {144}, 277 2003.

Synthesis Of [2h, 13c]M [2h2m 13c], And [2h3,, 13c] Methyl Aryl Sulfones And Sulfoxides

DOEpatents

Martinez, Rodolfo A.; Alvarez, Marc A.; Silks, III, Louis A.; Unkefer, Clifford J.; Schmidt, Jurgen G.

2004-07-20

The present invention is directed to labeled compounds, [.sup.2 H.sub.1, .sup.13 C], [.sup.2 H.sub.2, .sup.13 C] and [.sup.2 H.sub.3, .sup.13 C]methyl aryl sulfones and [.sup.2 H.sub.1, .sup.13 C], [.sup.2 H.sub.2, .sup.13 C] and [.sup.2 H.sub.3, .sup.13 C]methyl aryl sulfoxides, wherein the .sup.13 C methyl group attached to the sulfur of the sulfone or sulfoxide includes exactly one, two or three deuterium atoms and the aryl group is selected from the group consisting of 1-naphthyl, substituted 1-naphthyl, 2-naphthyl, substituted 2-naphthyl, and phenyl groups with the structure: ##STR1## wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4 and R.sub.5 are each independently, hydrogen, a C.sub.1 -C.sub.4 lower alkyl, a halogen, an amino group from the group consisting of NH.sub.2, NHR and NRR' where R and R' are each a C.sub.1 -C.sub.4 lower alkyl, a phenyl, or an alkoxy group. The present invention is also directed to processes of preparing methyl aryl sulfones and methyl aryl sulfoxides.

Synthesis, spectroscopic investigation and theoretical studies of 2-((E)-(2-(2-cyanoacetyl)hydrazono)methyl)-4-((E)-phenyldiazenyl)phenyl methyl carbonate

NASA Astrophysics Data System (ADS)

Arokiasamy, A.; Manikandan, G.; Thanikachalam, V.; Gokula Krishnan, K.

2017-04-01

Synthesis and computational optimization studies have been carried out by Hartree-Fock (HF) and Density Functional Theory (DFT-B3LYP) methods with 6-31+G(d, p) basis set for 2-((E)-(2-(2-cyanoacetyl)hydrazono)methyl)-4-((E)-phenyldiazenyl)phenyl methyl carbonate (CHPMC). The stable configuration of CHPMC was confirmed theoretically by potential energy surface scan analysis. The complete vibrational assignments were performed on the basis of total energy distribution (TED) analysis. The vibrational properties studied by IR and Raman spectroscopic data complemented by quantum chemical calculations support the formation of intramolecular hydrogen bond. Furthermore, the UV-Vis spectra are interpreted in terms of TD-DFT quantum chemical calculations. The shapes of the simulated absorption spectra are in good agreement with the experimental data. The comparison between the experimental and theoretical values of FT-IR, FT-Raman vibrational spectra, NMR (1H and 13C) and UV-Vis spectra have also been discussed.

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

USGS Publications Warehouse

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

1995-01-01

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

Geissoschizine methyl ether N-oxide, a new alkaloid with antiacetylcholinesterase activity from Uncaria rhynchophylla.

PubMed

Jiang, Wei-Wei; Su, Jia; Wu, Xing-De; He, Juan; Peng, Li-Yan; Cheng, Xiao; Zhao, Qin-Shi

2015-01-01

Geissoschizine methyl ether N-oxide, a new oxindole alkaloid, along with 14 known alkaloids, was isolated from the aerial part of Uncaria rhynchophylla. Their structures were identified by comprehensive spectral methods, including 2D NMR experiments, and confirmed by comparing with the literature data. In vitro acetylcholinesterase (AChE) inhibitory activity assay showed that the new compound exhibited anti-AChE activity with IC₅₀ value of 23.4 μM.

Searching for trans ethyl methyl ether in Orion KL★,★★

PubMed Central

Tercero, B.; Cernicharo, J.; López, A.; Brouillet, N.; Kolesniková, L.; Motiyenko, R. A.; Margulès, L.; Alonso, J. L.; Guillemin, J.-C.

2015-01-01

We report on the tentative detection of trans ethyl methyl ether (tEME), t-CH3CH2OCH3, through the identification of a large number of rotational lines from each one of the spin states of the molecule towards Orion KL. We also search for gauche-trans-n-propanol, Gt-n-CH3CH2CH2OH, an isomer of tEME in the same source. We have identified lines of both species in the IRAM 30 m line survey and in the ALMA Science Verification data. We have obtained ALMA maps to establish the spatial distribution of these species. Whereas tEME mainly arises from the compact ridge component of Orion, Gt-n-propanol appears at the emission peak of ethanol (south hot core). The derived column densities of these species at the location of their emission peaks are ≤(4.0 ± 0.8) × 1015 cm−2 and ≤(1.0 ± 0.2)× 1015 cm−2 for tEME and Gt-n-propanol, respectively. The rotational temperature is ~100 K for both molecules. We also provide maps of CH3OCOH, CH3CH2OCOH, CH3OCH3, CH3OH, and CH3CH2OH to compare the distribution of these organic saturated O-bearing species containing methyl and ethyl groups in this region. Abundance ratios of related species and upper limits to the abundances of non-detected ethers are provided. We derive an abundance ratio N(CH3OCH3)/N(tEME) ≥ 150 in the compact ridge of Orion. PMID:26869726

DFT study on the adsorption of diethyl, ethyl methyl, and dimethyl ethers on the surface of gallium doped graphene

NASA Astrophysics Data System (ADS)

Shokuhi Rad, Ali; Sani, Emad; Binaeian, Ehsan; Peyravi, Majid; Jahanshahi, Mohsen

2017-04-01

In this study, we used density functional theory (DFT) to search on the adsorption properties of three important compounds of ether family; diethyl ether (DEE), ethyl methyl ether (EME), and dimethyl ether (DME) on the surface of Gallium doped graphene (GaG). We used three functionals (B3LYP, wb97xd, and MPW1PW91) for optimization and calculation of adsorption energy. After fully optimization, we scrutinized on the charge allocations on the adsorbed ethers as well as GaG (at the area of interaction) based on natural bond orbitals (NBO). Besides, we have calculated the amount of charge transfer upon adsorption of each analyte. We revel that GaG is an ideal adsorbent for chemisorption of all above-mentioned ethers. There is a little difference between the values of adsorption; -123.5, -120, and -118.3 kJ/mol (based on wb97xd) for DEE, EME, and DME, respectively. We found significant changes in the electronic structure of both adsorbent and adsorbate upon adsorption. Moreover, results of charge analyses confirm GaG is a p-type semiconductor.

POLYBROMINATED DIPHENYL ETHERS (PBDES) CONTAMINATION OF UNITED STATES FOOD

EPA Science Inventory

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

DEVELOPMENT OF PHYSIOLOGICAL-BASED PHARMACOKINETIC MODEL FOR DERMAL ABSORPTION NAD PENETRATION OF METHYL TERTIARY BUTYL ETHER IN HUMANS

EPA Science Inventory

Background: Methyl tertiary butyl ether (MTBE) is a volatile organic chemical that is added to gasoline as an octane booster and to reduce vehicular emissions of carbon monoxide. MTBE is introduced into the environment through fuel spills, leakage of storage tanks, and evaporat...

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

EPA Science Inventory

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

Metabolism of aspirin and procaine in mice pretreated with O-4-nitrophenyl methyl(phenyl)phosphinate or O-4-nitrophenyl diphenylphosphinate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Joly, J.M.; Brown, T.M.

Concentrations of (carboxyl-/sup 14/C)procaine in blood of mice were increased threefold for 27 min by exposure to O-4-nitrophenyl diphenylphosphinate 2 hr prior to (carboxyl-/sup 14/C)procaine injection ip, while there was no effect of O-4-nitrophenyl methyl(phenyl)phosphinate pretreatment. There was no effect of either organophosphinate on the primary hydrolysis of (acetyl-l-/sup 14/C)aspirin when assessed by the expiration of (/sup 14/C)carbon dioxide; however, O-4-nitrophenyl diphenylphosphinate pretreatment produced transient increases in blood concentrations of both (carboxyl-/sup 14/C)aspirin and (carboxyl-/sup 14/C)salicylic acid following administration of (carboxyl-/sup 14/C)aspirin. Liver carboxylesterase activity in O-4-nitrophenyl diphenylphosphinate pretreated mice was 11% of control activity. These results indicate the potentialmore » for drug interaction with O-4-nitrophenyl diphenylphosphinate but not with O-4-nitrophenyl methyl(phenyl)phosphinate. It appears that liver carboxylesterase activity has a minor role in hydrolysis of aspirin in vivo, but may be more important in procaine metabolism.« less

Asbestos-Induced Epithelial Changes in Organ Cultures of Hamster Trachea: Inhibition by Retinyl Methyl Ether

NASA Astrophysics Data System (ADS)

Mossman, B. T.; Craighead, J. E.; MacPherson, B. V.

1980-01-01

The epithelium of the hamster trachea in organ culture undergoes hyperplasia and squamous metaplasia after exposure to the amphibole types of asbestos, crocidolite and amosite. These changes are inhibited when the synthetic vitamin A analog, retinyl methyl ether, is incorporated into the culture medium. These findings suggest a possible use for retinoids in the prevention and treatment of respiratory tract disease associated with environmental exposure to asbestos.

Synthesis and characterization of 3-acetoxy-2-methyl-N-(phenyl)benzamide and 3-acetoxy-2-methyl-N-(4- methylphenyl)benzamide

NASA Astrophysics Data System (ADS)

Kırca, Başak Koşar; Çakmak, Şükriye; Kütük, Halil; Odabaşoğlu, Mustafa; Büyükgüngör, Orhan

2018-01-01

This study treats about two successfully synthesized secondary amide compounds 3-Acetoxy-2-methyl-N-(phenyl)benzamide, I and 3-Acetoxy-2-methyl-N-(4-methylphenyl)benzamide, II. Compounds were characterized by FTIR, 1H NMR, 13C NMR and X-ray single crystal diffraction analysis techniques. Single crystal X-ray diffraction analyses show that while I crystallized in the orthorhombic system with space group Pbca, II crystallized in the triclinic system with space group P-1 and the asymmetric unit of II consists of two crystallographically independent molecules. Lattice constants are a = 7.9713 (3) Å, b = 9.5059 (3) Å, c = 37.1762 (2) Å, Z = 8 for I and a = 7.5579 (8) Å, b = 8.8601 (8) Å, c = 23.363 (3) Å, α = 97.011 (9) °, β = 96.932 (9)°, γ = 90.051 (8)°, Z = 4 for II. Crystallographic studies also show that the supramolecular structures were stabilized by intramolecular, intermolecular hydrogen bonds and Csbnd H … π interactions for both compounds. Characteristic amide bonds were observed in IR and NMR spectra.

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

EPA Science Inventory

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

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

NASA Astrophysics Data System (ADS)

Semelsberger, Troy A.; Borup, Rodney L.

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

Searching for trans ethyl methyl ether in Orion KL⋆

NASA Astrophysics Data System (ADS)

Tercero, B.; Cernicharo, J.; López, A.; Brouillet, N.; Kolesniková, L.; Motiyenko, R. A.; Margulès, L.; Alonso, J. L.; Guillemin, J.-C.

2015-10-01

We report on the tentative detection of trans ethyl methyl ether (tEME), t-CH3CH2OCH3, through the identification of a large number of rotational lines from each one of the spin states of the molecule towards Orion KL. We also search for gauche-trans-n-propanol, Gt-n-CH3CH2CH2OH, an isomer of tEME in the same source. We have identified lines of both species in the IRAM 30 m line survey and in the ALMA Science Verification data. We have obtained ALMA maps to establish the spatial distribution of these species. Whereas tEME mainly arises from the compact ridge component of Orion, Gt-n-propanol appears at the emission peak of ethanol (south hot core). The derived column densities of these species at the location of their emission peaks are ≤(4.0 ± 0.8) × 1015 cm-2 and ≤(1.0 ± 0.2) × 1015 cm-2 for tEME and Gt-n-propanol, respectively. The rotational temperature is ~100 K for both molecules. We also provide maps of CH3OCOH, CH3CH2OCOH, CH3OCH3, CH3OH, and CH3CH2OH to compare the distribution of these organic saturated O-bearing species containing methyl and ethyl groups in this region. Abundance ratios of related species and upper limits to the abundances of non-detected ethers are provided. We derive an abundance ratio N(CH3OCH3)/N(tEME) ≥ 150 in the compact ridge of Orion. This paper makes use of the following ALMA data: ADS/JAO.ALMA#2011.0.00009.SV. ALMA is a partnership of ESO (representing its member states), NSF (USA), and NINS (Japan) with NRC (Canada), NSC, and ASIAA (Taiwan), and KASI (Republic of Korea), in cooperation with the Republic of Chile. The Joint ALMA Observatory is operated by ESO, AUI/NRAO, and NAOJ. This work was also based on observations carried out with the IRAM 30-m telescope. IRAM is supported by INSU/CNRS (France), MPG (Germany), and IGN (Spain).Appendix A is available in electronic form at http://www.aanda.org

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

PubMed

Levchuk, Irina; Bhatnagar, Amit; Sillanpää, Mika

2014-04-01

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

Electron Affinity of Phenyl-C61-Butyric Acid Methyl Ester (PCBM)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Larson, Bryon W.; Whitaker, James B.; Wang, Xue B.

2013-07-25

The gas-phase electron affinity (EA) of phenyl-C61-butyric acid methyl ester (PCBM), one of the best-performing electron acceptors in organic photovoltaic devices, is measured by lowtemperature photoelectron spectroscopy for the first time. The obtained value of 2.63(1) eV is only ca. 0.05 eV lower than that of C60 (2.68(1) eV), compared to a 0.09 V difference in their E1/2 values measured in this work by cyclic voltammetry. Literature E(LUMO) values for PCBM that are typically estimated from cyclic voltammetry, and commonly used as a quantitative measure of acceptor properties, are dispersed over a wide range between -4.3 and -3.62 eV; themore » reasons for such a huge discrepancy are analyzed here, and the protocol for reliable and consistent estimations of relative fullerene-based acceptor strength in solution is proposed.« less

Treatment Of Groundwater Contaminated With PAHs, Gasoline Hydrocarbons, And Methyl Tert-Butyl Ether In A Laboratory Biomass-Retaining Bioreactor

EPA Science Inventory

In this study, we investigated the treatability of co-mingled groundwater contaminated with polycyclic aromatic hydrocarbons (PAHs), gasoline hydrocarbons, and methyl tert-butyl ether (MtBE) using an ex-situ aerobic biotreatment system. The PAHs of interest were nap...

21 CFR 73.3122 - 4-[(2,4-dimethylphenyl)azo]-2,4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-one.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 1 2013-04-01 2013-04-01 false 4-[(2,4-dimethylphenyl)azo]-2,4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-one. 73.3122 Section 73.3122 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Medical...

21 CFR 73.3122 - 4-[(2,4-dimethylphenyl)azo]-2,4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-one.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 1 2014-04-01 2014-04-01 false 4-[(2,4-dimethylphenyl)azo]-2,4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-one. 73.3122 Section 73.3122 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Medical...

21 CFR 73.3122 - 4-[(2,4-dimethylphenyl)azo]-2,4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-one.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 1 2010-04-01 2010-04-01 false 4-[(2,4-dimethylphenyl)azo]-2,4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-one. 73.3122 Section 73.3122 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Medical...

21 CFR 73.3122 - 4-[(2,4-dimethylphenyl)azo]-2,4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-one.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 1 2012-04-01 2012-04-01 false 4-[(2,4-dimethylphenyl)azo]-2,4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-one. 73.3122 Section 73.3122 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Medical...

21 CFR 73.3122 - 4-[(2,4-dimethylphenyl)azo]-2,4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-one.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 1 2011-04-01 2011-04-01 false 4-[(2,4-dimethylphenyl)azo]-2,4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-one. 73.3122 Section 73.3122 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Medical...

2,2-Bis[(2-halo-4-aminophenoxy)phenyl]-hexafluoropropane

NASA Technical Reports Server (NTRS)

Jones, Robert J. (Inventor); Chang, Glenn E. C. (Inventor)

1985-01-01

There are provided the aromatic diamines 2,2-bis-[(2-halo-4-aminophenoxy)-phenyl]hexafluoropropane, where the attached ortho halogen is preferably chlorine, and 4,4'-bis(4-aminophenoxy)biphenyl, as novel monomers for polyimide polymerizations. The former, when reacted with 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride, provides a polyimide having exceptional high-temperature performance. The latter diamine is a low-cost monomer for polyimide production.

Synthesis and photophysical properties of halogenated derivatives of (dibenzoylmethanato)boron difluoride

NASA Astrophysics Data System (ADS)

Kononevich, Yuriy N.; Surin, Nikolay M.; Sazhnikov, Viacheslav A.; Svidchenko, Evgeniya A.; Aristarkhov, Vladimir M.; Safonov, Andrei A.; Bagaturyants, Alexander A.; Alfimov, Mikhail V.; Muzafarov, Aziz M.

2017-03-01

A series of (dibenzoylmethanato)boron difluoride (BF2DBM) derivatives with a halogen atom in one of the phenyl rings at the para-position were synthesized and used to elucidate the effects of changing the attached halogen atom on the photophysical properties of BF2DBM. The room-temperature absorption and fluorescence maxima of fluoro-, chloro-, bromo- and iodo-substituted derivatives of BF2DBM in THF are red-shifted by about 2-10 nm relative to the corresponding peaks of the parent BF2DBM. The fluorescence quantum yields of the halogenated BF2DBMs (except the iodinated derivative) are larger than that of the unsubstituted BF2DBM. All the synthesized compounds are able to form fluorescent exciplexes with benzene and toluene (emission maxima at λem = 433 and 445 nm, respectively). The conformational structure and electronic spectral properties of halogenated BF2DBMs have been modeled by DFT/TDDFT calculations at the PBE0/SVP level of theory. The structure and fluorescence spectra of exciplexes were calculated using the CIS method with empirical dispersion correction.

Poly(vinyl methyl ether) hydrogels at temperatures below the freezing point of water-molecular interactions and states of water.

PubMed

Pastorczak, Marcin; Dominguez-Espinosa, Gustavo; Okrasa, Lidia; Pyda, Marek; Kozanecki, Marcin; Kadlubowski, Slawomir; Rosiak, Janusz M; Ulanski, Jacek

2014-01-01

Water interacting with a polymer reveals a number of properties very different to bulk water. These interactions lead to the redistribution of hydrogen bonds in water. It results in modification of thermodynamic properties of water and the molecular dynamics of water. That kind of water is particularly well observable at temperatures below the freezing point of water, when the bulk water crystallizes. In this work, we determine the amount of water bound to the polymer and of the so-called pre-melting water in poly(vinyl methyl ether) hydrogels with the use of Raman spectroscopy, dielectric spectroscopy, and calorimetry. This analysis allows us to compare various physical properties of the bulk and the pre-melting water. We also postulate the molecular mechanism responsible for the pre-melting of part of water in poly(vinyl methyl ether) hydrogels. We suggest that above -60 °C, the first segmental motions of the polymer chain are activated, which trigger the process of the pre-melting.

Effects of deuteration of the methyl and phenyl hydrogens on the rotational spectrum of anisole-water

NASA Astrophysics Data System (ADS)

Giuliano, Barbara M.; Melandri, Sonia; Caminati, Walther

2017-07-01

The role of non-covalent interactions in determining the structure of the 1:1 anisole-water molecular complex has been investigated by the analysis of the rotational spectra of the complex formed by the C6H5OCD3 and C6D5OCH3 deuterated species of anisole recorded with pulsed jet Fourier transform microwave spectroscopy. The deuteration of the methyl and phenyl hydrogens does not affect the structure and the internal dynamics of the complex, differently from the deuteration of the water moiety, which leads to large isotopic effects (Giuliano et al., 2005).

Design synthesis and structure-activity relationship of 5-substituted (tetrahydronaphthalen-2yl)methyl with N-phenyl-N-(piperidin-2-yl)propionamide derivatives as opioid ligands.

PubMed

Deekonda, Srinivas; Rankin, David; Davis, Peg; Lai, Josephine; Vanderah, Todd W; Porecca, Frank; Hruby, Victor J

2016-01-15

Here, we report the design, synthesis and structure activity relationship of novel small molecule opioid ligands based on 5-amino substituted (tetrahydronaphthalen-2-yl)methyl moiety with N-phenyl-N-(piperidin-2-yl)propionamide derivatives. We synthesized various molecules including amino, amide and hydroxy substitution on the 5th position of the (tetrahydronaphthalen-2-yl)methyl moiety. In our further designs we replaced the (tetrahydronaphthalen-2-yl)methyl moiety with benzyl and phenethyl moiety. These N-phenyl-N-(piperidin-2-yl)propionamide analogues showed moderate to good binding affinities (850-4 nM) and were selective towards the μ opioid receptor over the δ opioid receptors. From the structure activity relationship studies, we found that a hydroxyl substitution at the 5th position of (tetrahydronapthalen-2yl)methyl group, ligands 19 and 20, showed excellent binding affinities 4 and 5 nM, respectively, and 1000 fold selectivity towards the μ opioid relative to the delta opioid receptor. The ligand 19 showed potent agonist activities 75±21 nM, and 190±42 nM in the GPI and MVD assays. Surprisingly the fluoro analogue 20 showed good agonist activities in MVD assays 170±42 nM, in contrast to its binding affinity results. Copyright © 2015 Elsevier Ltd. All rights reserved.

Vibrational spectroscopic (FT-IR and FT-Raman) studies, HOMO-LUMO, NBO analysis and MEP of 6-methyl-1-({[(2E)-2-methyl-3-phenyl-prop-2-en-1-yl]oxy}methyl)-1,2,3,4-tetra-hydroquinazoline-2,4-dione, a potential chemotherapeutic agent, using density functional methods.

PubMed

Sebastian, Sr S H Roseline; Al-Tamimi, Abdul-Malek S; El-Brollosy, Nasser R; El-Emam, Ali A; Yohannan Panicker, C; Van Alsenoy, Christian

2015-01-05

6-Methyl-1-({[(2E)-2-methyl-3-phenyl-prop-2-en-1-yl]oxy}methyl)-1,2,3,4-tetra-hydro quinazoline-2,4-dione was prepared via treatment of silylated 6-methylquinazoline-2,4-dione with bis-[(E)-2-methyl-3-phenylallyloxy]methane. FT-IR and FT-Raman spectra were recorded and analyzed. The vibrational wavenumbers were computed using DFT methods and are assigned with the help of potential energy distribution method. The first hyperpolarizability, infrared intensities and Raman activities also reported. The geometrical parameters of the title compound obtained from XRD studies are in agreement with the calculated (B3LYP) values. The stability of the molecule arising from hyper-conjugative interaction and charge delocalization has been analyzed using NBO analysis. The HOMO and LUMO analysis are used to determine the charge transfer within the molecule. MEP was performed by the B3LYP method and from the MEP it is evident that the negative charge covers the CO group and the positive region is over the phenyl ring and NH group. Copyright © 2014 Elsevier B.V. All rights reserved.

CONCENTRATIONS, SOURCES, AND FATE OF THE GASOLINE OXYGENATE METHYL TERT-BUTYL ETHER (MTBE) IN A MULTIPLE-USE LAKE. (R826282)

EPA Science Inventory

Discovery of the fuel additive methyl tert-butyl ether (MTBE) in
drinking water supplies is of concern to public health officials, water
suppliers, and the public. Despite recent policy decisions, few published
studies exist on the concentrations, sources, a...

Toxicokinetics of ethers used as fuel oxygenates.

PubMed

Dekant, W; Bernauer, U; Rosner, E; Amberg, A

2001-10-15

The toxicokinetics and biotransformation of methyl-tert.butyl ether (MTBE), ethyl-tert.butyl ether (ETBE) and tert.amyl-methyl ether (TAME) in rats and humans are summarized. These ethers are used as gasoline additives in large amounts, and thus, a considerable potential for human exposure exists. After inhalation exposure MTBE, ETBE and TAME are rapidly taken up by both rats and humans; after termination of exposure, clearance by exhalation and biotransformation to urinary metabolites is rapid in rats. In humans, clearance by exhalation is slower in comparison to rats. Biotransformation of MTBE and ETBE is both qualitatively and quantitatively similar in humans and rats after inhalation exposure under identical conditions. The extent of biotransformation of TAME is also quantitatively similar in rats and humans; the metabolic pathways, however, are different. The results suggest that reactive and potentially toxic metabolites are not formed during biotransformation of these ethers and that toxic effects of these compounds initiated by covalent binding to cellular macromolecules are unlikely.

Synthesis and spectral properties of Methyl-Phenyl pyrazoloquinoxaline fluorescence emitters: Experiment and DFT/TDDFT calculations

NASA Astrophysics Data System (ADS)

Gąsiorski, P.; Matusiewicz, M.; Gondek, E.; Uchacz, T.; Wojtasik, K.; Danel, A.; Shchur, Ya.; Kityk, A. V.

2018-01-01

Paper reports the synthesis and spectroscopic studies of two novel 1-Methyl-3-phenyl-1H-pyrazolo[3,4-b]quinoxaline (PQX) derivatives with 6-substituted methyl (MeMPPQX) or methoxy (MeOMPPQX) side groups. The optical absorption and fluorescence emission spectra are recorded in solvents of different polarity. Steady state and time-resolved spectroscopy provide photophysical characterization of MeMPPQX and MeOMPPQX dyes as materials for potential luminescence or electroluminescence applications. Measured optical absorption and fluorescence emission spectra are compared with quantum-chemical DFT/TDDFT calculations using long-range corrected xc-functionals, LRC-BLYP and CAM-B3LYP in combination with self-consistent reaction field model based on linear response (LR), state specific (SS) or corrected linear response (CLR) solvations. Performances of relevant theoretical models and approaches are compared. The reparameterized LRC-BLYP functional (ω = 0.231 Bohr-1) in combination with CLR solvation provides most accurate prediction of both excitation and emission energies. The MeMPPQX and MeOMPPQX dyes represent efficient fluorescence emitters in blue-green region of the visible spectra.

Crystal structure and Hirshfield analysis of the 4-(di-methyl-amino)-pyridine adduct of 4-meth-oxy-phenyl-borane.

PubMed

Shooter, Jesse; Allen, Caleb J; Tinsley, Colby W K; Zakharov, Lev N; Abbey, Eric R

2017-11-01

The title compound [systematic name: 4-(di-methyl-amino)-pyridine-4-meth-oxy-phenyl-borane (1/1)], C 14 H 19 BN 2 O, contains two independent mol-ecules in the asymmetric unit. Both molecules exhibit coplanar, mostly sp 2 -hybridized meth-oxy and di-methyl-amino substituents on their respective aromatic rings, consistent with π-donation into the aromatic systems. The B-H groups exhibit an intra-molecular close contact with a C-H group of the pyridine ring, which may be evidence of electrostatic attraction between the hydridic B-H and the electropositive aromatic C-H. There appears to be weak C-H⋯π(arene) inter-actions between two of the H atoms of an amino-methyl group and the meth-oxy-substituted benzene ring of the other independent mol-ecule, and another C-H⋯π (arene) inter-action between one of the pyridine ring H atoms and the same benzene ring.

Trans-ethyl methyl ether, the struggle for the detection of a complex molecule in hot cores

NASA Astrophysics Data System (ADS)

Fuchs, G. W.; Fuchs, U.; Giesen, T. F.; Wyrowski, F.

Many large and complex molecules of prebiotic importance have been found as constituents of interstellar clouds but their detection remains difficult and sometimes doubtful (Snyder et al. 2005). The complex spectrum of trans-ethyl methyl ether (EME) has been investigated in the laboratory (Fuchs et al. 2003) up to 350 GHz and is now known with high frequency precision, see Figure 1. In this work we present an extensive search for EME towards G34.26, NGC6334(I), Orion KL, SgrB2(N) and W51e2 in the 1 to 3 mm wavelength region. These sources have previously been shown to have a rich chemistry of complex molecules. The IRAM 30m telescope at Pico Veleta, Spain and the SEST 15m radio telescope in La Silla, Chile have been used for the observations. We looked at 5 - 11 frequency bands where EME has strong transitions. All sources were examined using long integration times up to 220 min (on+off), elevations greater 40◦ and under good weather conditions. For our analysis of the data we used the method of rotational-temperature-diagrams but also the myXCLASS (written by Peter Schilke) extension program to the GILDAS (Grenoble Image and Line Data Analysis Software) software which enabled us to simulate spectra of several molecules including their linewidth and intensities at the same time, see Figure 2. With this program a consistency check of molecular abundances and overall composition is possible even in dense spectra with many overlapping lines. The effect of the source size on the measured intensities has been considered and cross checks with other important molecules such as methanol, ethanol and di-methyl ether have been performed. Charnley et al. (2001) assigned one line in W51 e1/e2 and one line in Orion KL at 160.1 GHz, as well as a line in SgrB2(N) at 79.6 GHz to trans-ethyl methyl ether. From their isolated measurements, the column density of EME was estimated to be in the range 1014-1015 cm-2 in Sgr B2(N) corresponding to a fractional abundance of 10

Electronic properties of electron-doped [6,6]-phenyl-C61-butyric acid methyl ester and silylmethylfullerene

NASA Astrophysics Data System (ADS)

Furutani, Sho; Okada, Susumu

2017-06-01

Electronic properties of electron-doped chemically decorated C60 fullerenes, [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) and silylmethylfullerene (SIMEF), by a planar electrode were studied using density functional theory combined with the effective screening medium method to simulate the heterointerface between the chemically decorated C60 and cationic counter materials. We find that the distribution of accumulated electrons and induced electric field depend on the molecular arrangement with respect to the external electric field of the electrode. We also show that the quantum capacitance of the molecule is sensitive to molecular arrangement owing to the asymmetric distribution of the accumulated electrons.

HIGH LEVELS OF MONOAROMATIC COMPOUNDS LIMIT THE USE OF SOLID-PHASE MICROEXTRACTION OF METHYL TERTIARY BUTYL ETHER AND TERTIARY BUTYL ALCOHOL

EPA Science Inventory

Recently, two papers reported the use of solid-phase microextraction (SPME) with polydimethylsiloxane(PDMS)/Carboxen fibers to determine trace levels of methyl tertiary butyl ether (MTBE) and tertiary butyl alcohol (tBA) in water. Attempts were made to apply this technique to th...

Anti-Helicobacter pylori activity of derivatives of the phthalide-containing antibacterial agents spirolaxine methyl ether, CJ-12,954, CJ-13,013, CJ-13,102, CJ-13,104, CJ-13,108 and CJ-13,015.

PubMed

Radcliff, Fiona J; Fraser, John D; Wilson, Zoe E; Heapy, Amanda M; Robinson, James E; Bryant, Christina J; Flowers, Christopher L; Brimble, Margaret A

2008-06-01

The naturally occurring phthalide-containing antibiotics spirolaxine methyl ether, CJ-12,954, CJ-13,013, CJ-13,015, CJ-13,102, CJ-13,103, CJ-13,104 and CJ-13,108, have been reported to exhibit anti-H. pylori activity. However, the exact stereochemistry of spirolaxine methyl ether, CJ-12,954 or CJ-13,013, contributing to this observed activity has not been confirmed. The anti-H. pylori activity of several analogues of spirolaxine methyl ether, CJ-12,954 and CJ-13,013 of defined stereochemistry together with the anti-H. pylori activity of several indole analogues of the simpler phthalide-containing antibiotics CJ-13,102, CJ-13,104, CJ-13,108 and CJ-13,015 is reported herein. A 1:1 mixture of spiroacetals 5b and 6b in which the phthalide substituent exhibited (3R)-stereochemistry was sixty times more active than the corresponding 1:1 mixture of spiroacetals with (3S)-stereochemistry. Notably, the unnatural (2''S)-diastereomer of spirolaxine methyl ether exhibited more potent anti-H. pylori activity than the natural product spirolaxine methyl ether. The 4,6-dimethoxyindoles 9, 10, 11 and 13 were all found to be less active than their parent compounds 1, 2, 3 and 4, respectively. Chain-shortened 4,6-dimethoxyindole analogue 12 of CJ-13,108 3 and 4,6-dimethoxyindole-spiroacetal 13 exhibited weak anti-H. pylori activity thus providing future opportunity for drug discovery programs.

Customer exposure to MTBE, TAME, C6 alkyl methyl ethers, and benzene during gasoline refueling.

PubMed

Vainiotalo, S; Peltonen, Y; Ruonakangas, A; Pfäffli, P

1999-02-01

We studied customer exposure during refueling by collecting air samples from customers' breathing zone. The measurements were carried out during 4 days in summer 1996 at two Finnish self-service gasoline stations with "stage I" vapor recovery systems. The 95-RON (research octane number) gasoline contained approximately 2.7% methyl tert-butyl ether (MTBE), approximately 8.5% tert-amyl methyl ether (TAME), approximately 3.2% C6 alkyl methyl ethers (C6 AMEs), and 0.75% benzene. The individual exposure concentrations showed a wide log-normal distribution, with low exposures being the most frequent. In over 90% of the samples, the concentration of MTBE was higher (range <0.02-51 mg/m3) than that of TAME. The MTBE values were well below the short-term (15 min) threshold limits set for occupational exposure (250-360 mg/m3). At station A, the geometric mean concentrations in individual samples were 3.9 mg/m3 MTBE and 2. 2 mg/m3 TAME. The corresponding values at station B were 2.4 and 1.7 mg/m3, respectively. The average refueling (sampling) time was 63 sec at station A and 74 sec at station B. No statistically significant difference was observed in customer exposures between the two service stations. The overall geometric means (n = 167) for an adjusted 1-min refueling time were 3.3 mg/m3 MTBE and 1.9 mg/m3 TAME. Each day an integrated breathing zone sample was also collected, corresponding to an arithmetic mean of 20-21 refuelings. The overall arithmetic mean concentrations in the integrated samples (n = 8) were 0.90 mg/m3 for benzene and 0.56 mg/m3 for C6 AMEs calculated as a group. Mean MTBE concentrations in ambient air (a stationary point in the middle of the pump island) were 0.16 mg/m3 for station A and 0.07 mg/m3 for station B. The mean ambient concentrations of TAME, C6 AMEs, and benzene were 0.031 mg/m3, approximately 0.005 mg/m3, and approximately 0.01 mg/m3, respectively, at both stations. The mean wind speed was 1.4 m/sec and mean air temperature was 21

N-(4-Meth-oxy-phen-yl)-6-methyl-2-phenyl-5-{[4-(tri-fluoro-meth-yl)anilino]meth-yl}pyrimidin-4-amine.

PubMed

Cieplik, Jerzy; Pluta, Janusz; Bryndal, Iwona; Lis, Tadeusz

2013-11-27

The title compound, C26H23F3N4O, crystallizes with two symmetry-independent mol-ecules in the asymmetric unit, denoted A and B, which differ mainly in the rotation of the meth-oxy-phenyl ring. The -CF3 group of mol-ecule B is disordered by rotation, with the F atoms split over two sets of sites; the occupancy factor for the major component is 0.853 (4). The dihedral angles between the pyrimidine ring and the attached phenyl, meth-oxy-phenyl and tri-fluoro-methyl-phenyl rings are 8.1 (2), 37.5 (2) and 70.7 (2)°, respectively, in mol-ecule A, and 9.3 (2), 5.3 (2) and 79.7 (2)° in mol-ecule B. An intra-molecular N-H⋯N hydrogen bond occurs in each mol-ecule. In the crystal, two crystallographically independent mol-ecules associate into a dimer via a pair of N-H⋯N hydrogen bonds, with a resulting R 2 (2)(12) ring motif and π-π stacking inter-actions [centroid-centroid distance = 3.517 (4) Å] between the pyrimidine rings. For the A mol-ecules, there are inter-molecular C-H⋯O hydrogen bonds between an aryl C atom of meth-oxy-phenyl ring and a meth-oxy O atom of an adjacent mol-ecule. A similar inter-action is lacking in the B mol-ecules.

CHLORINATED SOLVENT PLUME CONTROL

EPA Science Inventory

This lecture will cover recent success in controlling and assessing the treatment of shallow ground water plumes of chlorinated solvents, other halogenated organic compounds, and methyl tert-butyl ether (MTBE).

Optical properties of conjugated poly(3-hexylthiophene)/[6,6]-phenylC61-butyric acid methyl ester composites

NASA Astrophysics Data System (ADS)

Lioudakis, Emmanouil; Othonos, Andreas; Alexandrou, Ioannis; Hayashi, Yasuhiko

2007-10-01

In this work, we present the evolution of optical constants as a function of [6,6]-phenylC61-butyric acid methyl ester (PCBM) concentration for conjugated poly(3-hexylthiophene)/[6,6]-phenylC61-butyric acid methyl ester composites. The PCBM concentration of the utilized samples varies from 1to50wt%. The dielectric functions for all these composites reveal electronic structural changes as a result of the addition of PCBM. We have deconvoluted the contribution of the substrate using a two-layer Fabry-Pérot structural model. The extracted optical properties contain crucial absorption peaks of singlet exciton states and vibronic sidebands for poly(3-hexylthiophene) (P3HT) conjugated polymer as well as two PCBM-related states at higher energies. With the addition of PCBM, we have observed a limit of 20wt% PCBM beyond which two discrete energy levels (3.64 and 4.67eV) appear in the spectrum. For the highest concentration composite, the results suggest that the interchain interactions provide a small excitonic contribution in the absorption spectrum at energies where the conjugated polymer absorbs (1.85-2.7eV) and a strong rise of PCBM states (3.64 and 4.67eV) which are responsible for the subsequent exciton dissociation. In addition, the energy gap between the higher occupied molecular orbitals and the lower unoccupied molecular orbitals of the highest concentration composite (50wt%) is 1.85eV. The tuning of the optical properties of P3HT with the addition of PCBM shows that ellipsometry can be used to monitor layer concentration toward optimization of plastic solar cells.

Insight into the theoretical and experimental studies of 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone N(4)-methyl-N(4)- phenylthiosemicarbazone - A potential NLO material

NASA Astrophysics Data System (ADS)

Sangeetha, K. G.; Aravindakshan, K. K.; Safna Hussan, K. P.

2017-12-01

The synthesis, geometrical parameters, spectroscopic studies, optimised molecular structure, vibrational analysis, Mullikan population analysis, MEP, NBO, frontier molecular orbitals and NLO effects of 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone N-(4)-methyl-N-(4)-phenylthiosemicarbazone, C25H23N5OS (L1) have been communicated in this paper. A combined experimental and theoretical approach was used to explore the structure and properties of the compound. For computational studies, Gaussian 09 program was used. Starting geometry of molecule was taken from X-ray refinement data and has been optimized by using DFT (B3LYP) method with the 6-31+G (d, p) basis sets. NBO analysis gave insight into the strongly delocalized structure, responsible for the nonlinearity and hence the stability of the molecule. Frontier molecular orbitals have been defined to forecast the global reactivity descriptors of L1. The computed first-order hyperpolarizability (β) of the compound is 2 times higher than that of urea and this account for its nonlinear optical property. Simultaneously, a molecular docking study of the compound was performed using GLIDE Program. For this, three biological enzymes, histone deacetylase, ribonucleotide reductase and DNA methyl transferase, were selected as receptor molecules.

Nontargeted Screening of Halogenated Organic Compounds in Bottlenose Dolphins (Tursiops truncatus) from Rio de Janeiro, Brazil.

PubMed

Alonso, Mariana B; Maruya, Keith A; Dodder, Nathan G; Lailson-Brito, José; Azevedo, Alexandre; Santos-Neto, Elitieri; Torres, Joao P M; Malm, Olaf; Hoh, Eunha

2017-02-07

To catalog the diversity and abundance of halogenated organic compounds (HOCs) accumulating in high trophic marine species from the southwestern Atlantic Ocean, tissue from bottlenose dolphins (Tursiops truncatus) stranded or incidentally captured along the coast of Rio de Janeiro, Brazil, were analyzed by a nontargeted approach based on GC×GC/TOF-MS. A total of 158 individual HOCs from 32 different structural classes were detected in the blubber of 4 adult male T. truncatus. Nearly 90% of the detected compounds are not routinely monitored in the environment. DDT-related and mirex/dechlorane-related compounds were the most abundant classes of anthropogenic origin. Methoxy-brominated diphenyl ethers (MeO-BDEs) and chlorinated methyl- and dimethyl bipyrroles (MBPs and DMBPs) were the most abundant natural products. Reported for the first time in southwestern Atlantic cetaceans and in contrast to North American marine mammals, chlorinated MBPs and DMBPs were more abundant than their brominated and/or mixed halogenated counterparts. HOC profiles in coastal T. truncatus from Brazil and California revealed a distinct difference, with a higher abundance of MeO-BDEs, mirex/dechloranes and chlorinated bipyrroles in the Brazilian dolphins. Thirty-six percent of the detected HOCs had an unknown structure. These results suggest broad geographical differences in the patterns of bioaccumulative chemicals found in the marine environment and indicate the need to develop more complete catalogs of HOCs from various marine environments.

21 CFR 172.515 - Synthetic flavoring substances and adjuvants.

Code of Federal Regulations, 2012 CFR

2012-04-01

...-hydroxyundecanoic acid γ-lactone; peach aldehyde; aldehyde C-14. Undecenal. 2-Undecanone; methyl nonyl ketone. 9.... Acetanisole; 4′-methoxyacetophenone. Acetophenone; methyl phenyl ketone. Allyl anthranilate. Allyl butyrate... ethyl ether. Benzyl formate. 3-Benzyl-4-heptanone; benzyl dipropyl ketone. Benzyl isobutyrate. Benzyl...

21 CFR 172.515 - Synthetic flavoring substances and adjuvants.

Code of Federal Regulations, 2013 CFR

2013-04-01

...-hydroxyundecanoic acid γ-lactone; peach aldehyde; aldehyde C-14. Undecenal. 2-Undecanone; methyl nonyl ketone. 9.... Acetanisole; 4′-methoxyacetophenone. Acetophenone; methyl phenyl ketone. Allyl anthranilate. Allyl butyrate... ethyl ether. Benzyl formate. 3-Benzyl-4-heptanone; benzyl dipropyl ketone. Benzyl isobutyrate. Benzyl...

21 CFR 172.515 - Synthetic flavoring substances and adjuvants.

Code of Federal Regulations, 2011 CFR

2011-04-01

...-hydroxyundecanoic acid γ-lactone; peach aldehyde; aldehyde C-14. Undecenal. 2-Undecanone; methyl nonyl ketone. 9.... Acetanisole; 4′-methoxyacetophenone. Acetophenone; methyl phenyl ketone. Allyl anthranilate. Allyl butyrate... ethyl ether. Benzyl formate. 3-Benzyl-4-heptanone; benzyl dipropyl ketone. Benzyl isobutyrate. Benzyl...

21 CFR 172.515 - Synthetic flavoring substances and adjuvants.

Code of Federal Regulations, 2010 CFR

2010-04-01

...-hydroxyundecanoic acid γ-lactone; peach aldehyde; aldehyde C-14. Undecenal. 2-Undecanone; methyl nonyl ketone. 9.... Acetanisole; 4′-methoxyacetophenone. Acetophenone; methyl phenyl ketone. Allyl anthranilate. Allyl butyrate... ethyl ether. Benzyl formate. 3-Benzyl-4-heptanone; benzyl dipropyl ketone. Benzyl isobutyrate. Benzyl...

DIPPR Project 871 For 1995 - Thermodynamic Properties and Ideal-Gas Enthalpies of Formation for Methyl Benzoate, Ethyl Benzoate, (R)-(+)-Limonene, Tert-Amyl Methyl Ether, Trans-Crotonaldehyde, and

DOE Office of Scientific and Technical Information (OSTI.GOV)

Steele, W.V.

2002-07-01

Ideal-gas enthalpies of formation of methyl benzoate, ethyl benzoate, (R)-(+)-limonene, tert-amyl methyl ether, trans-crotonaldehyde, and diethylene glycol are reported. The standard energy of combustion and hence standard enthalpy of formation of each compound in the liquid phase has been measured using an oxygen rotating-bomb calorimeter without rotation. Vapor pressures were measured to a pressure limit of 270 kPa or the lower decomposition point for each of the six compounds using a twin ebulliometric apparatus. Liquid-phase densities along the saturation line were measured for each compound over a range of temperature (ambient to a maximum of 548 K). A differential scanningmore » calorimeter was used to measure two-phase (liquid + vapor) heat capacities for each compound in the temperature region ambient to the critical temperature or lower decomposition point. For methyl benzoate and tert-amyl methyl ether, critical temperatures and critical densities were determined from the DSC results and corresponding critical pressures derived from the fitting procedures. Fitting procedures were used to derive critical temperatures, critical pressures, and critical densities for each of the remaining compounds. The results of the measurements were combined to derive a series of thermophysical properties including critical temperature, critical density, critical pressure, acentric factor, enthalpies of vaporization (restricted to within {+-}50 K of the temperature region of the experimentally determined vapor pressures), and heat capacities along the saturation line. Wagner-type vapor-pressure equations were derived for each compound. All measured and derived values were compared with those obtained in a search of the literature. Recommended critical parameters are listed for each of the compounds studied. Group-additivity parameters, useful in the application of the Benson gas-phase group-contribution correlations, were derived.« less

Fixation of chiral smectic liquid crystal (S)-(+)-4-(2-methyl-1-butyloyloxy)phenyl 4-[1-(propenoyloxy) butiloxy] benzoate using UV curing techniques

DOE Office of Scientific and Technical Information (OSTI.GOV)

Afrizal,, E-mail: rizalunj04@yahoo.com; Nurdelima,; Umeir

2014-03-24

Chiral Smectic Liquid Crystal (S)-(+)-4-(2-methyl-1-butyloyloxy)phenyl 4-[1-(propenoyloxy) butiloxy] benzoate has been synthesized using method of steglich esterification at room temperature. The mesomorphic behavior of chiral smectic at 55°C that showed schlieren texture in POM analysis. Fixation of structure chiral smectic liquid crystal by means of photopolymerization of monomer (S)-(+)-4-(2-methyl-1-butyloyloxy)phenyl 4-[1-(propenoyloxy) butiloxy] benzoate under UV irradiation which called UV curing techniques. The curing process using UV 3 lamps 100 volt at 60°C for an hour. The product of photopolymerization could be seen by analysis of FTIR spectra both monomer and polymer. FTIR spectra of monomer, two peaks for ester carbonyl and C-Cmore » double bond groups appeared at 1729.09 cm-1and 3123.46 cm{sup −1}. After UV curing process, peak for the carbonyl group at 1729.09 cm{sup −1} decreased and a new peak at 1160.21 cm{sup −1} appeared due to the carbonyl group attached to a C-C bond group and then peak at 3123.46 cm{sup −1} for C-C double bond group was disappeared.« less

Customer exposure to MTBE, TAME, C6 alkyl methyl ethers, and benzene during gasoline refueling.

PubMed Central

Vainiotalo, S; Peltonen, Y; Ruonakangas, A; Pfäffli, P

1999-01-01

We studied customer exposure during refueling by collecting air samples from customers' breathing zone. The measurements were carried out during 4 days in summer 1996 at two Finnish self-service gasoline stations with "stage I" vapor recovery systems. The 95-RON (research octane number) gasoline contained approximately 2.7% methyl tert-butyl ether (MTBE), approximately 8.5% tert-amyl methyl ether (TAME), approximately 3.2% C6 alkyl methyl ethers (C6 AMEs), and 0.75% benzene. The individual exposure concentrations showed a wide log-normal distribution, with low exposures being the most frequent. In over 90% of the samples, the concentration of MTBE was higher (range <0.02-51 mg/m3) than that of TAME. The MTBE values were well below the short-term (15 min) threshold limits set for occupational exposure (250-360 mg/m3). At station A, the geometric mean concentrations in individual samples were 3.9 mg/m3 MTBE and 2. 2 mg/m3 TAME. The corresponding values at station B were 2.4 and 1.7 mg/m3, respectively. The average refueling (sampling) time was 63 sec at station A and 74 sec at station B. No statistically significant difference was observed in customer exposures between the two service stations. The overall geometric means (n = 167) for an adjusted 1-min refueling time were 3.3 mg/m3 MTBE and 1.9 mg/m3 TAME. Each day an integrated breathing zone sample was also collected, corresponding to an arithmetic mean of 20-21 refuelings. The overall arithmetic mean concentrations in the integrated samples (n = 8) were 0.90 mg/m3 for benzene and 0.56 mg/m3 for C6 AMEs calculated as a group. Mean MTBE concentrations in ambient air (a stationary point in the middle of the pump island) were 0.16 mg/m3 for station A and 0.07 mg/m3 for station B. The mean ambient concentrations of TAME, C6 AMEs, and benzene were 0.031 mg/m3, approximately 0.005 mg/m3, and approximately 0.01 mg/m3, respectively, at both stations. The mean wind speed was 1.4 m/sec and mean air temperature was 21

Synthesis, spectroscopic investigations (X-ray, NMR and TD-DFT), antimicrobial activity and molecular docking of 2,6-bis(hydroxy(phenyl)methyl)cyclohexanone.

PubMed

Barakat, Assem; Ghabbour, Hazem A; Al-Majid, Abdullah Mohammed; Soliman, Saied M; Ali, M; Mabkhot, Yahia Nasser; Shaik, Mohammed Rafi; Fun, Hoong-Kun

2015-07-21

The synthesis of 2,6-bis(hydroxy(phenyl)methyl)cyclohexanone 1 is described. The molecular structure of the title compound 1 was confirmed by NMR, FT-IR, MS, CHN microanalysis, and X-ray crystallography. The molecular structure was also investigated by a set of computational studies and found to be in good agreement with the experimental data obtained from the various spectrophotometric techniques. The antimicrobial activity and molecular docking of the synthesized compound was investigated.

40 CFR 721.10271 - 3′H-Cyclopropa[1,9][5,6]fullerene-C60-Ih-3′-butanoic acid, 3′-phenyl-, methyl ester.

Code of Federal Regulations, 2013 CFR

2013-07-01

... CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.10271 3′H-Cyclopropa[1,9][5,6]fullerene-C60-Ih-3′-butanoic acid, 3′-phenyl-, methyl ester. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as 3′H-Cyclopropa[1,9][5,6...

40 CFR 721.10271 - 3′H-Cyclopropa[1,9][5,6]fullerene-C60-Ih-3′-butanoic acid, 3′-phenyl-, methyl ester.

Code of Federal Regulations, 2014 CFR

2014-07-01

... CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.10271 3′H-Cyclopropa[1,9][5,6]fullerene-C60-Ih-3′-butanoic acid, 3′-phenyl-, methyl ester. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as 3′H-Cyclopropa[1,9][5,6...

Environmental behavior and fate of methyl tert-butyl ether (MTBE)

USGS Publications Warehouse

Squillace, Paul J.; Pankow, James F.; Korte, Nic E.; Zogorski, John S.

1996-01-01

When gasoline that has been oxygenated with methyl tert-butyl ether (MTBE) comes in contact with water, large amounts of MTBE can dissolve; at 25 degrees Celsius the water solubility of MTBE is about 5,000 milligrams per liter for a gasoline that is 10 percent MTBE by weight. In contrast, for a nonoxygenated gasoline, the total hydrocarbon solubility in water is typically about 120 milligrams per liter. MTBE sorbs only weakly to soil and aquifer materials; therefore, sorption will not significantly retard MTBE's transport by ground water. In addition, MTBE generally resists degradation in ground water. The half-life of MTBE in the atmosphere can be as short as 3 days in a regional airshed. MTBE in the air tends to partition into atmospheric water, including precipitation. However, washout of gas-phase MTBE by precipitation would not, by itself, greatly alter the gas-phase concentration of the compound in the air. The partitioning of MTBE to precipitation is nevertheless strong enough to allow for up to 3 micrograms per liter or more inputs of MTBE to surface and ground water.

Chemical Action of Halogenated Agents in Fire Extinguishing

NASA Technical Reports Server (NTRS)

Belles, Frank E.

1955-01-01

The action of halogenated agents in preventing flame propagation in fuel-air mixtures in laboratory tests is discussed in terms of a possible chemical mechanism. The mechanism chosen is that of chain-breaking reactions between agent and active particles (hydrogen and oxygen atoms and hydroxyl radicsls). Data from the literature on the flammability peaks of n-heptane agent-air mixtures are treated. Ratings of agent effectiveness in terms of the fuel equivalent of the agent, based on both fuel and agent concentrations at the peak, are proposed as preferable to ratings in terms of agent concentration alone. These fuel-equivalent ratings are roughly correlated by reactivities assigned to halogen and hydrogen atoms in the agent molecules. It is concluded that the presence of hydrogen in agent need not reduce its fire-fighting ability, provided there is enough halogen to make the agent nonflammable. A method is presented for estimating from quenching-distance data a rate constant for the reaction of agent with active particles. A quantitative result is obtained for methyl bromide. This rate constant predicts the observed peak concentration of methyl bromide quite well. However, more data are needed to prove the validity of the method. The assumption that hal.ogenatedagents act mainly by chain-bresking reactions with active particles is consistent with the experimental facts and should help guide the selection of agents for further tests.

Methyl tert-butyl ether (MTBE) in finished drinking water in Germany.

PubMed

Kolb, Axel; Püttmann, Wilhelm

2006-03-01

In the present study 83 finished drinking water samples from 50 cities in Germany were analyzed for methyl tert-butyl ether (MTBE) content with a detection limit of 10 ng/L. The detection frequency was 46% and the concentrations ranged between 17 and 712 ng/L. Highest concentrations were found in the community water systems (CWSs) of Leuna and Spergau in Saxony-Anhalt. These CWSs are supplied with water possibly affected by MTBE contaminated groundwater. MTBE was detected at concentrations lower than 100 ng/L in drinking water supplied by CWSs using bank filtered water from Rhine and Main Rivers. The results from Leuna and Spergau show that large groundwater contaminations in the vicinity of CWSs pose the highest risk for MTBE contamination in drinking water. CWSs using bank filtered water from Rhine and Main Rivers are susceptible to low MTBE contaminations in finished drinking water. All measured MTBE concentrations were below proposed limit values for drinking water.

The physiological disposition of the uricosuric-saluretic agent (6,7-dichloro-2-methyl-1-oxo-2-phenyl-5-indanyloxy)acetic acid (MK-196) in the rat, dog, and monkey.

PubMed

Zacchei, A G; Wishousky, T I

1976-01-01

The physiological disposition of a new saluretic-uricosuric agent, (6,7-dichloro-2-methyl-1-oxo-2-phenyl-5-indanyloxy)acetic acid (MK-196), was studied in the rat, dog, and monkey. MK-196 was well absorbed and showed minimal metabolism in these species. Peak plasma levels of radioactivity and drug occurred 0.5-2 hr after oral administration at a dose of 2.5 mg/kg. Essentially all of the radioactivity present in the plasma during the first day was intact MK-196. Following a single dose, a long terminal half-life for plasma radioactivity was observed in the dog (approximately 68 hr) and monkey (approximately 105 hr). The chronic administration of MK-196 to dogs resulted in a dose-related plasma profile and showed no tendency to increase or decrease with dosing. However, upon repeated drug administration to monkeys, the plasma levels of drug increased and then decreased, possibly due to hypochloremia and secondary metabolic alkalosis. Fecal excretion was the predominant route of tracer elimination in the dog (approximately 80%) and rat (approximately 94%), whereas the monkey eliminated the majority of the dose (approximately 60%) via the urine. Minimal metabolism was noted in the three lower species; most of the urinary, plasma, and fecal radioactivity was accounted for as intact drug and its glucuronide conjugate. Three minor metabolites, which were present in dog bile, plasma, and urine, were characterized as: (l,7-dichloro-1alpha-hydroxy-2-methyl-2-phenyl-5-indanyloxy)acetic acid, I; (6,7-dichloro-2-(4-hydroxyphenyl)-2-methyl-2-oxo-5-indanyloxy)acetic acid, II; and 2-methyl-2-phenyl-5-hydroxy-6,7-dichloro-1-indanone, III. The monkey urine and plasma also contained small amounts of II.

40 CFR 721.10409 - Poly(oxyalkylenediyl), .alpha. - [ [ [methyl - 3 - [ [ [ (polyfluoroalkyl)oxy]carbonyl ] amino...

Code of Federal Regulations, 2013 CFR

2013-07-01

.... - [ [ [methyl - 3 - [ [ [ (polyfluoroalkyl)oxy]carbonyl ] amino] phenyl]amino]carbonyl] - .omega. - methoxy... Specific Chemical Substances § 721.10409 Poly(oxyalkylenediyl), .alpha. - [ [ [methyl - 3 - [ [ [ (polyfluoroalkyl)oxy]carbonyl ] amino] phenyl]amino]carbonyl] - .omega. - methoxy - (generic). (a) Chemical...

Synergistic effects of influenza and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) can be eliminated by the use of influenza therapeutics: experimental evidence for the multi-hit hypothesis.

PubMed

Sadasivan, Shankar; Sharp, Bridgett; Schultz-Cherry, Stacey; Smeyne, Richard Jay

2017-01-01

Central Nervous System inflammation has been implicated in neurodegenerative disorders including Parkinson's disease (Ransohoff, Science 353: 777-783, 2016; Kannarkat et al. J. Parkinsons Dis. 3: 493-514, 2013). Here, we examined if the H1N1 influenza virus (Studahl et al. Drugs 73: 131-158, 2013) could synergize with the parkinsonian toxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (Jackson-Lewis et al. in Mark LeDoux (ed) Movement Disorders: Genetics and Models : 287-306, Elsevier, 2015) to induce a greater microglial activation and loss of substantia nigra pars compacta dopaminergic neurons than either insult alone. H1N1-infected animals administered 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine exhibit a 20% greater loss of substantia nigra pars compacta dopaminergic neurons than occurs from the additive effects of H1N1 or 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine alone ( p  < 0.001). No synergistic effects were found in microglial activation. The synergistic dopaminergic neuron loss is eliminated by influenza vaccination or treatment with oseltamivir carboxylate. This work shows that multiple insults can induce synergistic effects; and even these small changes can be significant as it might allow one to cross a phenotypic disease threshold that would not occur from individual non-interacting exposures. Our observations also have important implications for public health, providing impetus for influenza vaccination or prompt treatment with anti-viral medications upon influenza diagnosis.

Methylation patterns of aquatic humic substances determined by 13C NMR spectroscopy

USGS Publications Warehouse

Thorn, K.A.; Steelink, C.; Wershaw, R. L.

1987-01-01

13C NMR spectroscopy is used to examine the hydroxyl group functionality of a series of humic and fulvic acids from different aquatic environments. Samples first are methylated with 13C-labeled diazomethane. The NMR spectra of the diazomethylated samples allow one to distinguish between methyl esters of carboxylic acids, methyl ethers of phenolic hydroxyls, and methyl ethers of phenolic hydroxyls adjacent to two substituents. Samples are then permethylated with 13C-labeled methyl iodide/NaH. 13C NMR spectra of permethylated samples show that a significant fraction of the hydroxyl groups is not methylated with diazomethane alone. In these spectra methyl ethers of carbohydrate and aliphatic hydroxyls overlap with methyl ethers of phenolic hydroxyls. Side reactions of the methyltion procedure including carbon methylation in the CH3I/NaH procedure, are also examined. Humic and fulvic acids from bog, swamp, groundwater, and lake waters showssome differences in their distribution of hydroxyl groups, mainly in the concentrations of phenolic hydroxyls, which may be attributed to their different biogeochemical origins. ?? 1987.

High-temperature polyimides prepared from 2,2-bis-[(2-halo-4-aminophenoxy)-phenyl]hexafluoropropane

NASA Technical Reports Server (NTRS)

Jones, Robert J. (Inventor); Chang, Glenn E. C. (Inventor)

1984-01-01

There are provided the aromatic diamines 2,2-bis-[(2-halo-4-aminophenoxy)-phenyl]hexafluoropropane, where the attached ortho halogen is preferably chlorine, and 4,4'-bis(4-aminophenoxy)biphenyl, as novel monomers for polyimide polymerizations. The former, when reacted with 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride, provides a polyimide having exceptional high-temperature performance. The latter diamine is a low-cost monomer for polyimide production.

Dangguijakyak-san protects dopamine neurons against 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced neurotoxicity under postmenopausal conditions.

PubMed

Lee, Jin-Moo; Hwang, Deok-Sang; Kim, Hyo Geun; Lee, Chang-Hoon; Oh, Myung Sook

2012-02-15

Dangguijakyak-san protects dopamine neurons against 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced neurotoxicity under postmenopausal conditions. Dangguijakyak-san (DJS), a famous traditional herbal formula, has long been used to treat gynecological disorders, including postmenopausal symptoms. This study evaluated the effects and mechanism of DJS on 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced neurotoxicity in a postmenopausal mouse model induced by ovariectomy. Three weeks after ovariectomy, C57bl/6 female mice were divided randomly into (1) control, (2) MPTP (30 mg/kg/day, i.p., 5 days), (3) MPTP+estrogen (50 μg/kg/day, i.p., 5 days), and (4) MPTP+DJS (50 mg/kg/day, p.o., 5 days) groups. We investigated the behavioral recovery and dopamine neuron protection of DJS using the pole test and tyrosine hydroxylase (TH) immunohistochemistry. We also explored the mechanism by assessing the protein expression of Bax, Bcl-2, cytochrome c, and cleaved caspase-3. DJS treatment restored the movement behavior impaired by MPTP, showing a similar or better effect than estrogen. DJS protected TH-immunoreactive cells and fibers in the nigrostriatal region from MPTP toxicity. In addition, DJS inhibited the Bcl-2 decrease and Bax increase in mitochondria, cytochrome c release to the cytosol, and caspase-3 activation induced by MPTP. DJS showed behavior recovery and dopamine neuron protection against MPTP-induced toxicity via anti-apoptotic activities in ovariectomized female mice. These results suggest that DJS treatment is effective for postmenopausal neurodegenerative diseases. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Mitochondria targeted peptides protect against 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine neurotoxicity.

PubMed

Yang, Lichuan; Zhao, Kesheng; Calingasan, Noel Y; Luo, Guoxiong; Szeto, Hazel H; Beal, M Flint

2009-09-01

A large body of evidence suggests that mitochondrial dysfunction and oxidative damage play a role in the pathogenesis of Parkinson's disease (PD). A number of antioxidants have been effective in animal models of PD. We have developed a family of mitochondria-targeted peptides that can protect against mitochondrial swelling and apoptosis (SS peptides). In this study, we examined the ability of two peptides, SS-31 and SS-20, to protect against 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) neurotoxicity in mice. SS-31 produced dose-dependent complete protection against loss of dopamine and its metabolites in striatum, as well as loss of tyrosine hydroxylase immunoreactive neurons in substantia nigra pars compacta. SS-20, which does not possess intrinsic ability in scavenging reactive oxygen species, also demonstrated significant neuroprotective effects on dopaminergic neurons of MPTP-treated mice. Both SS-31 and SS-20 were very potent (nM) in preventing MPP+ (1-methyl-4-phenylpyridinium)-induced cell death in cultured dopamine cells (SN4741). Studies with isolated mitochondria showed that both SS-31 and SS-20 prevented MPP+-induced inhibition of oxygen consumption and ATP production, and mitochondrial swelling. These findings provide strong evidence that these neuroprotective peptides, which target both mitochondrial dysfunction and oxidative damage, are a promising approach for the treatment of PD.

Pharmacological evaluation of halogenated and non-halogenated arylpiperazin-1-yl-ethyl-benzimidazoles as D(2) and 5-HT(2A) receptor ligands.

PubMed

Tomić, Mirko; Vasković, Djurdjica; Tovilović, Gordana; Andrić, Deana; Penjišević, Jelena; Kostić-Rajačić, Sladjana

2011-05-01

Five groups of previously synthesized and initially screened non-substituted and 4-halogenated arylpiperazin-1-yl-ethyl-benzimidazoles were estimated for their in-vitro binding affinities at the rat D(2) , 5-HT(2A) , and α(1) -adrenergic receptors. Among all these compounds, 2-methoxyphenyl and 2-chlorophenyl piperazines demonstrate the highest affinities for the tested receptors. The effects of 4-halogenation of benzimidazoles reveal that substitution with bromine may greatly increase the affinity of the compounds for the studied receptors, while the effect of substitution with chlorine is less remarkable. Most of the tested components show 5-HT(2A)/D(2) pK(i) binding ratios slightly above or less than 1, while only 4-chloro-6-(2-{4-[3-(trifluoromethyl)phenyl]piperazin-1-yl}ethyl)-1H-benzimidazole expresses an appropriate higher binding ratio (1.14), which was indicated for atypical neuroleptics. This compound exhibits a non-cataleptic action in rats and prevents d-amphetamine-induced hyperlocomotion in mice, which suggest its atypical antipsychotic potency. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Synthesis, structural elucidation and pharmacological properties of some 5-acetyl-3,4-dihydro-6-methyl-4-(substituted phenyl)-2(1H) -pyrimidinones.

PubMed

Yarim, M; Sarac, S; Ertan, M; Batu, O S; Erol, K

1999-06-30

In this study, the synthesis of some new 5-acetyl-3,4-dihydro-6-methyl-4-(substituted phenyl)-2(1H)-pyrimidinones has been reported. The compounds were prepared by the Biginelli reaction of acetylacetone with aromatic aldehydes and urea. The structures of the compounds were characterized by UV, IR, 1H NMR, 13C NRM, mass spectra and elementary analysis. The calcium antagonistic activity of these compounds was tested in vitro on rat ileum precontracted with 4 x 10(-3) M barium chloride.

Sulfobutyl ether β-cyclodextrin (Captisol(®) ) and methyl β-cyclodextrin enhance and stabilize fluorescence of aqueous indocyanine green.

PubMed

DeDora, Daniel J; Suhrland, Cassandra; Goenka, Shilpi; Mullick Chowdhury, Sayan; Lalwani, Gaurav; Mujica-Parodi, Lilianne R; Sitharaman, Balaji

2016-10-01

As the only FDA-approved near-infrared fluorophore, indocyanine green (ICG) is commonly used to image vasculature in vivo. ICG degrades rapidly in solution, which limits its usefulness in certain applications, including time-sensitive surgical procedures. We propose formulations that address this shortcoming via complexation with β-cyclodextrin derivatives (β-CyD), which are known to create stabilizing inclusion complexes with hydrophobic molecules. Here, we complexed ICG with highly soluble methyl β-CyD and FDA-approved sulfobutyl ether β-CyD (Captisol(®) ) in aqueous solution. We measured the fluorescence of the complexes over 24 h. We found that both CyD+ICG complexes exhibit sustained fluorescence increases of >2.0× versus ICG in water and >20.0× in PBS. Using transmission electron microscopy, we found evidence of reduced aggregation in complexes versus ICG alone. We thus conclude that this reduction in aggregation helps mitigate fluorescence autoquenching of CyD+ICG complexes compared in ICG alone. We also found that while ICG complexed with methyl β-CyD severely reduced the viability of MRC-5 fibroblasts, ICG complexed with sulfobutyl ether β-CyD had no effect on viability. These results represent an important first step toward enhancing the utility of aqueous ICG by reducing aggregation-dependent fluorescence degradation. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 1457-1464, 2016. © 2015 Wiley Periodicals, Inc.

40 CFR 65.154 - Halogen scrubbers and other halogen reduction devices.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 15 2011-07-01 2011-07-01 false Halogen scrubbers and other halogen... Routing to a Fuel Gas System or a Process § 65.154 Halogen scrubbers and other halogen reduction devices. (a) Halogen scrubber and other halogen reduction device equipment and operating requirements. (1) An...

Epigallocatechin gallate protects dopaminergic neurons against 1-methyl-4- phenyl-1,2,3,6-tetrahydropyridine-induced neurotoxicity by inhibiting microglial cell activation.

PubMed

Li, Rui; Peng, Ning; Du, Fang; Li, Xu-ping; Le, Wei-dong

2006-04-01

To observe whether the dopaminergic neuroprotective effect of (-)-epigallocatechin gallate (EGCG) is associated with its inhibition of microglial cell activation in vivo. The effects of EGCG at different doses on dopaminergic neuronal survival were tested in a methyl-4-phenyl-pyridinium (MPP+)-induced dopaminergic neuronal injury model in the primary mesencephalic cell cultures. With unbiased stereological method, tyrosine hydroxylase-immunoreactive (TH-ir) cells were counted in the A8, A9 and A10 regions of the substantia nigra (SN) in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated C57BL/6 mice. The effect of EGCG on microglial activation in the SN was also investigated. Pretreatment with EGCG (1 to 100 micromol/L) significantly attenuated MPP+-induced TH-ir cell loss by 22.2% to 80.5% in the mesencephalic cell cultures. In MPTP-treated C57BL/6 mice, EGCG at a low concentration (1 mg/kg) provided significant protection against MPTP-induced TH-ir cell loss by 50.9% in the whole nigral area and by 71.7% in the A9 region. EGCG at 5 mg/kg showed more prominent protective effect than at 1 or 10 mg/kg. EGCG pretreatment significantly inhibited microglial activation and CD11b expression induced by MPTP. EGCG exerts potent dopaminergic neuroprotective activity by means of microglial inhibition, which shed light on the potential use of EGCG in treatment of Parkinson's disease.

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

PubMed

Ensminger, M P; Hess, F D

1985-05-01

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

Structures and anti-inflammatory properties of 4-halogenated -mofebutazones

NASA Astrophysics Data System (ADS)

Reichelt, Hendrik; Paradies, Henrich H.

2018-02-01

The crystal structures of the 4-halogenated (hal: F, Cl, Br)-4-butyl-1-phenyl-1,3-pyrolidine-dione (mofebutazone) are determined, and compared with their solution structures. The racemic 4-halogenated mofebutazone approximants crystallize in a monoclinic space group with four molecules in the unit cell. The 4-hal-mofebutazone molecules reveal strong hydrogen bonding between the hydrogen atom located at the N-2 nitrogen atom and a carbonyl oxygen atom of an adjacent 4-hal-mofebutazone molecule. The hydrogen bond angle for 4-Br-mifebutazone N (2)sbnd H (1)⋯O (1) is 173(3) °, so that the hydrogen bond is essentially linear indicating an infinite chain hydrogen bond network. The 3d and 2d structures are stabilized by π-π and σ-π interactions, short intermolecular distances, and apolar forces between adjacently stacked phenyl rings. Small-angle-X-ray scattering (SAXS) experiments and osmometric measurements reveal the presence of dimers for the 4-hal-mofebutazone molecules. Molecular simulations indicate similar solution structure factors for the 4-hal-mofebutazones solutions, S(Q), and in the solid state. There is a strong indication that the [1,1,0], [1,0,0], and [1,0,0] periodicities of the 4-Brsbnd , 4-Clsbnd and 4-F-mofebutazone in the crystalline solid state were also present in the solution phase. The biochemical and cellular activities of the different 4-hal-mofebutazones were monitored by the magnitude of their inhibition of the PGE2 biosynthesis through the cyclo-oxygenase (COX-1) in macrophages, and on the inhibition of LTD4 (5-lipoxygenase) in polymorphonuclear leukocytes.

Platinum(0)-mediated C-O bond activation of ethers via an SN2 mechanism.

PubMed

Ortuño, Manuel A; Jasim, Nasarella A; Whitwood, Adrian C; Lledós, Agustí; Perutz, Robin N

2016-11-29

A computational study of the C(methyl)-O bond activation of fluorinated aryl methyl ethers by a platinum(0) complex Pt(PCyp 3 ) 2 (Cyp = cyclopentyl) (N. A. Jasim, R. N. Perutz, B. Procacci and A. C. Whitwood, Chem. Commun., 2014, 50, 3914) demonstrates that the reaction proceeds via an S N 2 mechanism. Nucleophilic attack of Pt(0) generates an ion pair consisting of a T-shaped platinum cation with an agostic interaction with a cyclopentyl group and a fluoroaryloxy anion. This ion-pair is converted to a 4-coordinate Pt(ii) product trans-[PtMe(OAr F )(PCyp 3 ) 2 ]. Structure-reactivity correlations are fully consistent with this mechanism. The Gibbs energy of activation is calculated to be substantially higher for aryl methyl ethers without fluorine substituents and higher still for alkyl methyl ethers. These conclusions are in accord with the experimental results. Further support was obtained in an experimental study of the reaction of Pt(PCy 3 ) 2 with 2,3,5,6-tetrafluoro-4-allyloxypyridine yielding the salt of the Pt(η 3 -allyl) cation and the tetrafluoropyridinolate anion [Pt(PCy 3 ) 2 (η 3 -allyl)][OC 5 NF 4 ]. The calculated activation energy for this reaction is significantly lower than that for fluorinated aryl methyl ethers.

Abiotic Formation of Methyl Halides in the Terrestrial Environment

NASA Astrophysics Data System (ADS)

Keppler, F.

2011-12-01

Methyl chloride and methyl bromide are the most abundant chlorine and bromine containing organic compounds in the atmosphere. Since both compounds have relatively long tropospheric lifetimes they can effectively transport halogen atoms from the Earth's surface, where they are released, to the stratosphere and following photolytic oxidation form reactive halogen gases that lead to the chemical destruction of ozone. Methyl chloride and methyl bromide account for more than 20% of the ozone-depleting halogens delivered to the stratosphere and are predicted to grow in importance as the chlorine contribution to the stratosphere from anthropogenic CFCs decline. Today methyl chloride and methyl bromide originate mainly from natural sources with only a minor fraction considered to be of anthropogenic origin. However, until as recently as 2000 most of the methyl chloride and methyl bromide input to the atmosphere was considered to originate from the oceans, but investigations in recent years have clearly demonstrated that terrestrial sources such as biomass burning, wood-rotting fungi, coastal salt marshes, tropical vegetation and organic matter degradation must dominate the atmospheric budgets of these trace gases. However, many uncertainties still exist regarding strengths of both sources and sinks, as well as the mechanisms of formation of these naturally occurring halogenated gases. A better understanding of the atmospheric budget of both methyl chloride and methyl bromide is therefore required for reliable prediction of future ozone depletion. Biotic and abiotic methylation processes of chloride and bromide ion are considered to be the dominant pathways of formation of these methyl halides in nature. In this presentation I will focus on abiotic formation processes in the terrestrial environment and the potential parameters that control their emissions. Recent advances in our understanding of the abiotic formation pathway of methyl halides will be discussed. This will

Can simultaneous contact allergies to phenyl glycidyl ether and epoxy resins of the bisphenol A/F-types be explained by contamination of the epoxy resins?

PubMed

Pontén, Ann; Zimerson, Erik; Bruze, Magnus

2008-11-01

Simultaneous contact allergies to epoxy resins based on diglycidyl ether of bisphenol A (DGEBA-R) or epoxy resins of the bisphenol F-type and the reactive diluent phenyl glycidyl ether (PGE) have been reported. The reason might be cross-reactivity, exposure to an epoxy resin system with PGE as a component, or contamination by PGE in the epoxy resin. To study contamination by PGE, 20 commercial epoxy resins were analysed for the presence of PGE. To study contact allergy to PGE and its relation to epoxy resins by inserting PGE in the standard series. Among 2227 patients, 7 reacted to PGE. Of 23 (30%) patients, 7 with contact allergy to DGEBA-R and 7/19 (37%) with contact allergy to an epoxy resin of the bisphenol F-type reacted to PGE. All 7 patients with contact allergy to PGE reacted both to the DGEBA-R and to the epoxy resin of the bisphenol F-type. PGE was found in 90% of the investigated resins. The amounts of PGE ranged between 0.004% w/w and 0.18% w/w. Most probably, the presence of PGE as a contaminant in epoxy resins is of minor importance for the sensitization, but possibly the contamination of PGE might elicit contact dermatitis in individuals with a high reactivity to PGE.

Fabrication of One-Dimensional Zigzag [6,6]-PhenylC61-Butyric Acid Methyl Ester Nanoribbons from Two-Dimensional Nanosheets (Open Access: Author’s Final)

DTIC Science & Technology

2015-09-18

a derivative is the [6,6]-phenyl-C61-butyric acid methyl ester (PCBM), a C60 fullerene with a chemically bonded functional group. The addition of the...functional group, on the other hand, decreases the fullerene symmetry and conse- quently affects its crystallization.8 Although growth of crystalline C60...possibility to tune the grown structures to different morphologies.8 One-dimensional fullerene (C60) struc- tures, namely, nanorods and nanoribbons, are of

MOF-based catalysts for selective hydrogenolysis of carbon–oxygen ether bonds

DOE PAGES

Stavila, Vitalie; Parthasarathi, Ramakrishnan; Davis, Ryan W.; ...

2015-11-23

We demonstrate that metal–organic frameworks (MOFs) can catalyze hydrogenolysis of aryl ether bonds under mild conditions. Mg-IRMOF-74(I) and Mg-IRMOF-74(II) are stable under reducing conditions and can cleave phenyl ethers containing β-O-4, α-O-4, and 4-O-5 linkages to the corresponding hydrocarbons and phenols. Reaction occurs at 10 bar H 2 and 120 °C without added base. DFT-optimized structures and charge transfer analysis suggest that the MOF orients the substrate near Mg 2+ ions on the pore walls. Ti and Ni doping further increase conversions to as high as 82% with 96% selectivity for hydrogenolysis versus ring hydrogenation. Thus repeated cycling induces nomore » loss of activity, making this a promising route for mild aryl-ether bond scission.« less

PRODUCTS OF THE GAS-PHASE REACTIONS OF THE OH RADICAL WITH N-BUTYL METHYL ETHER AND 2-ISOPROPOXYETHANOL: REACTIONS OF ROC(O)< RADICALS. (R825252)

EPA Science Inventory

The products of the gas-phase reactions of the OH radical with n-butyl methyl ether and 2-isopropoxyethanol in the presence of NO have been investigated at 298 ? 2 K and 740 Torr total pressure of air by gas chromatography and in situ atmospheric pressure ionization...

Arylthioindole inhibitors of tubulin polymerization. 3. Biological evaluation, structure-activity relationships and molecular modeling studies.

PubMed

La Regina, Giuseppe; Edler, Michael C; Brancale, Andrea; Kandil, Sahar; Coluccia, Antonio; Piscitelli, Francesco; Hamel, Ernest; De Martino, Gabriella; Matesanz, Ruth; Díaz, José Fernando; Scovassi, Anna Ivana; Prosperi, Ennio; Lavecchia, Antonio; Novellino, Ettore; Artico, Marino; Silvestri, Romano

2007-06-14

The new arylthioindole (ATI) derivatives 10, 14-18, and 21-24, which bear a halogen atom or a small size ether group at position 5 of the indole moiety, were compared with the reference compounds colchicine and combretastatin A-4 for biological activity. Derivatives 10, 11, 16, and 21-24 inhibited MCF-7 cell growth with IC50 values <50 nM. A halogen atom (14-17) at position 5 caused a significant reduction in the free energy of binding of compound to tubulin, with a concomitant reduction in cytotoxicity. In contrast, methyl (21) and methoxy (22) substituents at position 5 caused an increase in cytotoxicity. Compound 16, the most potent antitubulin agent, led to a large increase (56%) in HeLa cells in the G2/M phase at 24 h, and at 48 h, 26% of the cells were hyperploid. Molecular modeling studies showed that, despite the absence of the ester moiety present in the previously examined analogues, most of the compounds bind in the colchicine site in the same orientation as the previously studied ATIs. Binding to beta-tubulin involved formation of a hydrogen bond between the indole and Thr179 and positioning of the trimethoxy phenyl group in a hydrophobic pocket near Cys241.

Triclosan and Hydroxylated Polybrominated Diphenyl Ethers in Lake and Esturaine Sediments

NASA Astrophysics Data System (ADS)

Arnold, W. A.; Kerrigan, J. F.; McNeill, K.; Erickson, P. R.; Grandbois, M.

2014-12-01

Halogenated diphenyl ethers are a class of emerging contaminants that includes the antibacterial compound triclosan and the flame retardant polybrominated diphenyl ethers (PBDEs). Both triclosan and hydroxylated polybrominated diphenyl ethers (OH-BDEs) are known to form dioxins when exposed to sunlight in aqueous solution. Thus, it is important to understand the sources and presence of these compounds in the environment, especially because OH-BDEs are breakdown products of PBDEs and also naturally produced compounds. In this work, the levels of OH-BDEs were determined in lake sediments from Minnesota and esturaine sediments from San Francisco Bay. Both surface sediments over a broad spatial area and sediment cores were collected and analyzed. Triclosan was used as a marker of wastewater as a source of the targeted emerging contaminants. The relationship between triclosan and OH-BDE levels provides insight into the importance of natural and anthropogenic influences on the levels of OH-BDEs.

40 CFR 721.10273 - 3′H-Cyclopropa[7,22][5,6]fullerene-C70-D5h(6)-3′-butanoic acid, 3′-phenyl-, methyl ester.

Code of Federal Regulations, 2014 CFR

2014-07-01

... CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.10273 3′H-Cyclopropa[7,22][5,6]fullerene-C70-D5h(6)-3′-butanoic acid, 3′-phenyl-, methyl ester. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substances identified as 3′H-Cyclopropa[7,22][5,6...

40 CFR 721.10272 - 3′H-Cyclopropa[8,25][5,6]fullerene-C70-D5h(6)-3′-butanoic acid, 3′-phenyl-,methyl ester.

Code of Federal Regulations, 2013 CFR

2013-07-01

... CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.10272 3′H-Cyclopropa[8,25][5,6]fullerene-C70-D5h(6)-3′-butanoic acid, 3′-phenyl-,methyl ester. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substances identified as 3′H-Cyclopropa[8,25][5,6...

40 CFR 721.10272 - 3′H-Cyclopropa[8,25][5,6]fullerene-C70-D5h(6)-3′-butanoic acid, 3′-phenyl-,methyl ester.

Code of Federal Regulations, 2014 CFR

2014-07-01

... CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.10272 3′H-Cyclopropa[8,25][5,6]fullerene-C70-D5h(6)-3′-butanoic acid, 3′-phenyl-,methyl ester. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substances identified as 3′H-Cyclopropa[8,25][5,6...

40 CFR 721.10273 - 3′H-Cyclopropa[7,22][5,6]fullerene-C70-D5h(6)-3′-butanoic acid, 3′-phenyl-, methyl ester.

Code of Federal Regulations, 2013 CFR

2013-07-01

... CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.10273 3′H-Cyclopropa[7,22][5,6]fullerene-C70-D5h(6)-3′-butanoic acid, 3′-phenyl-, methyl ester. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substances identified as 3′H-Cyclopropa[7,22][5,6...

New biphasic solvent system based on cyclopentyl methyl ether for the purification of a non-polar synthetic peptide by pH-zone refining centrifugal partition chromatography.

PubMed

Amarouche, Nassima; Boudesocque, Leslie; Borie, Nicolas; Giraud, Matthieu; Forni, Luciano; Butte, Alessandro; Edwards, Florence; Renault, Jean-Hugues

2014-06-01

A new type 1 ternary biphasic system composed of cyclopentyl methyl ether, dimethylformamide and water was developed, characterized and successfully used for the purification of a lipophilic, protected peptide by pH-zone refining centrifugal partition chromatography. The protected peptide is an 8-mer, key intermediate in bivalirudin (Angiomax®) synthesis and shows a very low solubility in the solvents usually used in liquid chromatography. All ionic groups, except the N-terminal end of the peptide, are protected by a benzyl group. The purification of this peptide was achieved with a purity of about 99.04% and a recovery of 94% using the new ternary biphasic system cyclopentyl methyl ether/dimethylformamide/water (49:40:11, v/v) in the descending pH-zone refining mode with triethylamine (28 mM) as the retainer and methanesulfonic acid (18 mM) as the eluter. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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

PubMed Central

Ensminger, Michael P.; Hess, F. Dan

1985-01-01

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

40 CFR 63.994 - Halogen scrubbers and other halogen reduction devices.

Code of Federal Regulations, 2012 CFR

2012-07-01

... halogen scrubber or other halogen reduction technique used to reduce the vent stream halogen atom mass... subpart shall determine the halogen atom mass emission rate prior to the combustion device according to...

40 CFR 63.994 - Halogen scrubbers and other halogen reduction devices.

Code of Federal Regulations, 2014 CFR

2014-07-01

... halogen scrubber or other halogen reduction technique used to reduce the vent stream halogen atom mass... subpart shall determine the halogen atom mass emission rate prior to the combustion device according to...

40 CFR 63.994 - Halogen scrubbers and other halogen reduction devices.

Code of Federal Regulations, 2010 CFR

2010-07-01

... halogen scrubber or other halogen reduction technique used to reduce the vent stream halogen atom mass... subpart shall determine the halogen atom mass emission rate prior to the combustion device according to...

40 CFR 63.994 - Halogen scrubbers and other halogen reduction devices.

Code of Federal Regulations, 2013 CFR

2013-07-01

... halogen scrubber or other halogen reduction technique used to reduce the vent stream halogen atom mass... subpart shall determine the halogen atom mass emission rate prior to the combustion device according to...

40 CFR 63.994 - Halogen scrubbers and other halogen reduction devices.

Code of Federal Regulations, 2011 CFR

2011-07-01

... halogen scrubber or other halogen reduction technique used to reduce the vent stream halogen atom mass... subpart shall determine the halogen atom mass emission rate prior to the combustion device according to...

IRON(III) NITRATE-CATALYZED FACILE SYNTHESIS OF DIPHENYLMETHYL (DPM) ETHERS FROM ALCOHOLS

EPA Science Inventory

Diphenyl methyl (DPM) ethers constitute important structural portion of some pharmaceutical entities and also as protective group for hydroxyl groups in synthetic chemistry. DPM ethers are normally prepared using concentrated acids or base as catalysts, which may result in the fo...

Methyl tert-butyl ether biodegradation by microbial consortia obtained from soil samples of gasoline-polluted sites in Mexico.

PubMed

Morales, Marcia; Velázquez, Elia; Jan, Janet; Revah, Sergio; González, Uriel; Razo-Flores, Elías

2004-02-01

Microbial consortia obtained from soil samples of gasoline-polluted sites were individually enriched with pentane, hexane, isooctane and toluene. Cometabolism with methyl tert-butyl ether, (MTBE), gave maximum degradation rates of 49, 12, 32 and 0 mg g(-1)protein h(-1), respectively. MTBE was fully degraded even when pentane was completely depleted with a cometabolic coefficient of 1 mgMTBE mg(-1)pentane. The analysis of 16S rDNA from isolated microorganisms in the pentane-adapted consortia showed that microorganisms could be assigned to Pseudomonas. This is the first work reporting the cometabolic mineralization of MTBE by consortium of this genus.

[Effects of methyl tertiary butyl ether on cell cycle and cell apoptosis].

PubMed

Zhou, W; Huang, G; Zhang, H; Ye, S

2000-07-01

To explore the effects of the new gasoline additive, methyl tertiary butyl ether (MTBE) on cell cycle and cell apoptosis. Flow cytometry was used to evaluate the effect of MTBE (1, 2, 4 microl/ml, 24 h) on NIH/3T3 cell cycles; and the effect of MTBE on Hela cell apoptosis was evaluated by detecting cell survival using crystal violet staining. Flow cytometry showed that MTBE could change NIH/3T3 cell cycles, decrease the number of cells in S stage, and arrest cells at G(2) + M stage. The results suggested that MTBE could affect NIH/3T3 cell cycles and induce cell proliferation. This situation existed 48 hours after the treatment, and cell cycles came back normal 96 hours after the treatment. By detecting cell survival using crystal violet staining, we found that MTBE could inhibit the apoptosis of Hela cells which was induced by tumor necrosis factor (TNF)alpha and cycloheximide. MTBE's carcinogenicity to animals may relate to induction of cell proliferation and inhibition of cell apoptosis.

Preparation of an Ester-Containing Grignard Reagent by Halogen-Metal Exchange

ERIC Educational Resources Information Center

Snider, Barry B.

2015-01-01

In this experiment, students carry out a halogen-metal exchange reaction of methyl 2-iodobenzoate with isopropylmagnesium chloride in THF at 0°C to afford 2-carbomethoxyphenylmagnesium chloride, which is treated with "p"-methoxybenzaldehyde to give a lactone (phthalide) product. This reaction introduces students to the modern method of…

Experimental and theoretical studies of the molecular structure of 7-Methyl-3-[(3-methyl-3-mesityl-cyclobutyl]-5-phenyl-5H-thiazolo[3,2-α]pyrimidine-6-carboxylic acid ethyl ester

NASA Astrophysics Data System (ADS)

Acar, Betül; Yilmaz, Ibrahim; Çalışkan, Nezihe; Cukurovali, Alaaddin

2017-07-01

In this work, the title molecule, 7-Methyl-3-[(3-methyl-3-mesityl-cyclobutyl]-5-phenyl-5H-thiazolo[3,2-α]pyrimidine-6-carboxylic acid ethyl ester (C30H34N2O2S1), was synthesized and characterized by FT-IR spectroscopy and single crystal X-ray diffraction. The compound crystallizes in the triclinic space group P21/c. with Z = 4, a = 14.1988(6), b = 19.0893(5), c = 10.1325(4) Å, V = 2674.56(17) A3. The optimized structure parameters of the studied molecule was determined theoretically using HF/6-31G(d) and B3LYP/6-31G(d) methods for ground state, and compared with previously reported experimental findings. The calculated harmonic vibrational frequencies are scaled and they are compared with experimental frequencies obtained by FT-IR spectra. The electronic properties, such as HOMO and LUMO energies, and molecular electrostatic potential (MEP) are also performed.

Pyrrolidone - a new solvent for the methylation of humic acid

USGS Publications Warehouse

Wershaw, R. L.; Pinckney, D.J.; Booker, S.E.

1975-01-01

In the past, humic acid has been methylated by suspending it in a solution of diazomethane in diethyl ether, and degrading the partly methylated humic acid to release those parts of the molecule that were methylated. Only small fragments of the molecule have been identified by this technique. In the procedure described here the humic acid is dissolved in 2-pyrrolidone and methylated by the addition of diazomethane in diethyl ether and ethanol to the solution. Because the humic acid is completely dissolved in the reaction medium, disaggregation of the humic acid particles takes place and much more complete methylation is obtained. The methylated products may be fractionated by countercurrent distribution and analyzed by mass spectrometry.

(E)-3-Methyl-2,6-di­phenyl­piperidin-4-one O-(3-methyl­benzo­yl)oxime

PubMed Central

Kathiravan, V.; Krishnan, K. Gokula; Mohandas, T.; Thanikachalam, V.; Sakthivel, P.

2014-01-01

In the title compound, C26H26N2O2, the piperidine ring exhibits a chair conformation. The phenyl rings are attached to the central heterocycle in an equatorial position. The dihedral angle between the planes of the phenyl rings is 57.58 (8)°. In the crystal, C—H⋯O inter­actions connect the mol­ecules into zigzag chains along [001]. PMID:25249925

The conformation of the monomethyl ethers of methyl beta-lactoside in D2O and Me2SO-d6 solutions.

PubMed

Fernández, P; Jiménez-Barbero, J

1993-10-04

The solution conformations of all the possible monomethyl ethers of methyl beta-lactoside have been analysed using molecular mechanics and dynamics calculations and nuclear magnetic resonance data (variable temperature and NOE experiments). The overall shape of all the compounds studied is fairly similar and may be described by conformers included in a low-energy region with phi = -100 +/- 40 degrees and psi = -135 +/- 35 degrees, which is ca. 5% of the total potential energy surface for the glycosidic linkages of the disaccharides.

In vitro cytotoxicity assessment of a West Virginia chemical spill mixture involving 4-methylcyclohexanemethanol and propylene glycol phenyl ether.

PubMed

Han, Alice A; Fabyanic, Emily B; Miller, Julie V; Prediger, Maren S; Prince, Nicole; Mouch, Julia A; Boyd, Jonathan

2017-04-01

Thousands of gallons of industrial chemicals, crude 4-methylcyclohexanemethanol (MCHM) and propylene glycol phenyl ether (PPh), leaked from industrial tanks into the Elk River in Charleston, West Virginia, USA, on January 9, 2014. A considerable number of people were reported to exhibit symptoms of chemical exposure and an estimated 300,000 residents were advised not to use or drink tap water. At the time of the spill, the existing toxicological data of the chemicals were limited for a full evaluation of the health risks, resulting in concern among those in the impacted regions. In this preliminary study, we assessed cell viability and plasma membrane degradation following a 24-h exposure to varying concentrations (0-1000 μM) of the two compounds, alone and in combination. Evaluation of different cell lines, HEK-293 (kidney), HepG2 (liver), H9c2 (heart), and GT1-7 (brain), provided insight regarding altered cellular responses in varying organ systems. Single exposure to MCHM or PPh did not affect cell viability, except at doses much higher than the estimated exposure levels. Certain co-exposures significantly reduced metabolic activity and increased plasma membrane degradation in GT1-7, HepG2, and H9c2 cells. These findings highlight the importance of examining co-exposures to fully understand the potential toxic effects.

Preparation and characterization of poly (arylene ether isoxazole)s by fluoride ion-mediated aromatic nucleophilic displacement reactions

NASA Technical Reports Server (NTRS)

Herbert, C. G.; Bass, R. G.

1994-01-01

As part of a continuing effort to prepare novel thermally stable high-performance polymers, poly(arylene ether isoxazole)s have been prepared by fluoride ion-catalyzed aromatic nucleophilic substitution reactions with bis(trimethylsiloxyphenyl) isoxazoles and activated bisarylhalides in diphenyl sulfone. Initial investigation involving the preparation of these materials with isoxazole bisphenols and activated bisarylhalides in the presence of potassium carbonate indicated that, under reaction conditions necessary to prepare high-molecular-weight materials, the isoxazole monomer was converted to an enamino ketone. This side reaction was avoided by using fluoride as a base. However, trimethylsilyl ether derivatives of the isoxazole bisphenols were required in these polymerizations for the preparation of high-molecular-weight materials. Moderate to high inherent viscosity eta(sub inh): 0.43-0.87 dl/g) materials with good thermal stability (air: 409-477 C, helium: 435-512 C) can be prepared by the silyl ether method. Glass transition temperatures ranged from 182 to 225 C for polymers with phenyl pendants and from 170 to 214 C for those without. Molecular weight control by 2% endcapping and the incorporation of a phenyl pendant at the 4 position of the isoxazole is necessary to yield polymers soluble in polar aprotic solvents at room temperature. There is evidence, however, indicating the existence of crosslinks between the polymer chains when the silyl ether approach is utilized.

Iodine(III) Derivatives as Halogen Bonding Organocatalysts.

PubMed

Heinen, Flemming; Engelage, Elric; Dreger, Alexander; Weiss, Robert; Huber, Stefan M

2018-03-26

Hypervalent iodine(III) derivatives are known as versatile reagents in organic synthesis, but there is only one previous report on their use as Lewis acidic organocatalysts. Herein, we present first strong indications for the crucial role of halogen bonding in this kind of catalyses. To this end, the solvolysis of benzhydryl chloride and the Diels-Alder reaction of cyclopentadiene with methyl vinyl ketone served as benchmark reactions for halide abstraction and the activation of neutral compounds. Iodolium compounds (cyclic diaryl iodonium species) were used as activators or catalysts, and we were able to markedly reduce or completely switch off their activity by sterically blocking one or two of their electrophilic axes. Compared with previously established bidentate cationic halogen bond donors, the monodentate organoiodine derivatives used herein are at least similarly active (in the Diels-Alder reaction) or even decidedly more active (in benzhydryl chloride solvolysis). © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Antibacterial activity of berberine-NorA pump inhibitor hybrids with a methylene ether linking group.

PubMed

Samosorn, Siritron; Tanwirat, Bongkot; Muhamad, Nussara; Casadei, Gabriele; Tomkiewicz, Danuta; Lewis, Kim; Suksamrarn, Apichart; Prammananan, Therdsak; Gornall, Karina C; Beck, Jennifer L; Bremner, John B

2009-06-01

Conjugation of the NorA substrate berberine and the NorA inhibitor 5-nitro-2-phenyl-1H-indole via a methylene ether linking group gave the 13-substituted berberine-NorA inhibitor hybrid, 3. A series of simpler arylmethyl ether hybrid structures were also synthesized. The hybrid 3 showed excellent antibacterial activity (MIC Staphylococcus aureus, 1.7 microM), which was over 382-fold more active than the parent antibacterial berberine, against this bacterium. This compound was also shown to block the NorA efflux pump in S. aureus.

Crystalline smectic E phase revisited in case of symmetrical dibenzo-18-crown-6-ether azomethine dimers

NASA Astrophysics Data System (ADS)

Cozan, Vasile; Ardeleanu, Rodinel; Airinei, Anton; Timpu, Daniel

2018-03-01

Three symmetric azomethine dimers having dibenzo-18-crown-6-ether as internal moiety and halogens (F, Cl, Br) as terminal functional groups were synthesized and characterized by FTIR and 1H NMR spectroscopy. Their thermal behavior was investigated by polarized optical microscopy (POM) and DSC techniques. Interesting textures have been observed at cooling by POM as being representative for a soft crystalline smectic phase. X-ray diffraction measurements in powder at room temperature exhibited a map of reflections corresponding to crystal E phase. The influence of molecular parameters (interdigitation parameter γ, dipole moment, molecular polarizability, halogen radius) on thermal behavior was discussed. The UV-Vis investigations allowed evaluation of photostability and a bathochromic effect was noticed with the increasing of halogen atom radius. Also the values of optical band gap (Eg) are higher than those corresponding to conjugated Schiff bases.

3-(6-Methyl-2-pyrid­yl)-2-phenyl-3,4-dihydro-1,3,2-benzoxaza­phosphinine 2-oxide

PubMed Central

Surendra Babu, V. H. H.; Krishnaiah, M.; Anil Kumar, M.; Suresh Reddy, C.; Kant, Rajni

2009-01-01

In the title compound, C19H17N2O2P, the six-membered 1,3,2-oxaza­phosphinine ring adopts a boat conformation with the phosphoryl O atom in an equatorial position. The dihedral angle between the 6-methyl-2-pyridyl and phenyl groups is 75.5 (1)°. These substituents are trans to each other, and are oriented at angles of 57.2 (1) and 74.8 (1)°, respectively, to the benzene ring. The crystal structure is stabilized by intra- and inter­molecular hydrogen bonds. The phosphoryl O atom participates in inter­molecular C—H⋯O inter­actions with the neighbouring mol­ecules, forming centrosymmetric R 2 2(14) dimers. PMID:21578300

[Occupational exposure to methyl tert-butyl ether (MTBE) at an oil refinery].

PubMed

Perbellini, L; Pasini, F; Prigioni, P; Rosina, A

2003-01-01

Methyl tert-butyl ether (MTBE) is widely used as an additive to gasoline, to increase oxygen content and reduce tailpipe emission of carbon monoxide. Our research dealt with 37 refinery workers in order to measure their occupational exposure to MTBE during two different seasonal periods. They provided blood and urine samples before and after a work shift during which they wore an active charcoal sampler for solvents. All samples were analysed by a gas-chromatograph equipped with a mass spectrometer detector. The concentration in air of MTBE was very low (median: 25 micrograms/m3 in spring and 5 micrograms/m3 in autumn). The blood and urine concentrations of MTBE at the end of the work shift were higher than those found before the shift. The increment in biological samples confirmed a small intake of MTBE by refinery workers: the biological monitoring of occupational exposure to this solvent yielded reliable results. Blood and urinary concentrations of MTBE obtained from workers split in relation to their smoking habit did not give a statistic significance to say that cigarette smoke is not a confusion factor in monitoring exposure to MTBE.

Proton-Ionizable Crown Ethers. A Short Review

DTIC Science & Technology

1989-05-30

acid methyl ester using sodium hydride as the base in tetrahydrofuran. The m3thyl ester group was hydrolyzed to the carboxylic acid as shown in Procedure...prepared via the appropriate hydroxydibenzo-crown ether and allyl bromide RýIý R2 or ethyl acrylate as shown in Procedure N. 5 2 . 5 6 Disulfonic acid ...similar to Procedure p. 7 4 Once the precursor binrephtho-crown was obtained, it was coupled with bromoacetic acid methyl ester and R, , - R

Photophysics and morphology of poly (3-dodecylthienylenevinylene)-[6,6]-phenyl-C{sub 61}-butyric acid methyl ester composite

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lafalce, E.; Toglia, P.; Jiang, X.

2012-05-21

A series of low band gap poly(3-dodecylthienylenevinylene) (PTV) with controlled morphological order have been synthesized and blended with the electron acceptor [6,6]-phenyl-C{sub 61}-butyric acid methyl ester (PCBM) for organic photovoltaic devices. Two polymers with the most and least side chain regioregularity were chosen in this work, namely the PTV010 and PTV55, respectively. Using photoluminescence, photo-induced absorption spectroscopy, and atomic force microscopy, we find no direct evidence of photoinduced charge transfer between the two constituents, independent of the bulk-heterojunction morphology of the film, although the possibility of formation of P{sup +}/C{sub 60}{sup -} charge transfer complex was not completely ruled out.more » The large exciton binding energy (E{sub b} = 0.6 eV) in PTV inhibits the photoinduced electron transfer from PTV to PCBM. In addition, excitons formed on polymer chains suffer ultrafast (« less

Wholly Aromatic Ether-imides. Potential Materials for n-Type Semiconductors

NASA Technical Reports Server (NTRS)

Dingemans, Theo J.; St.Clair, Terry L.; Samulski, Edward T.; Bushnell, Dennis M. (Technical Monitor)

2002-01-01

We report on the synthesis and characterization of a novel series low-molar-mass ether-imide rod-shaped model compounds. All ether-imides were obtained by terminating the appropriate rigid core dianhydride, i.e. pyromellitic dianhydride (PMDA), 1,4,5,8-naphthalenetetracarboxylic dianhydride (NDA), 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA), and 3,3,4,4'-oxydiphthalic dianhydride (ODPA) with three flexible aryl-ether tails of different chain length. The mono-functional aryl-ether amines, i.e. 4-(3-phenoxy-phenoxy)-phenylamine (2) and 4-(3-phenoxy-3-phenoxy-phenoxy)-phenylamine (4), were synthesized using standard fluoro-displacement and Ullmann condensation techniques. The corresponding ether-imide model compounds were obtained in high yields using a one-step solution imidization procedure. Increasing the number of meta-substituted aryl-ether units reduces the melt transition temperatures and at the same time it increases the solubility of the model compounds. Most model compounds are crystalline solids and form isotropic melts upon heating. 2,7-Bis-(-4-phenoxy-phenyl)-benzo[Imn][3,8]phenanthroline1,3,6,8-tetraone (NDA-n0), however, displays a smectic A (SA) when cooled from the isotropic phase, followed by what appears to be either a highly ordered smectic phase or a, columnar phase. This is the first example, known to date, in which a mesophase is detected in a wholly aromatic ether-imide compound. For all compounds we present spectroscopic data and X-ray diffraction data. Cyclic voltammetry was used to determine the redox behavior and pertinent energy levels of the model compounds.

Syntheses of all the possible monomethyl ethers and several deoxyhalo analogues of methyl beta-lactoside as ligands for the Ricinus communis lectins.

PubMed

Fernández, P; Jiménez-Barbero, J; Martín-Lomas, M

1994-02-17

The synthesis of all the possible monomethyl ethers of methyl beta-lactoside (1) has been performed from 1 in a straightforward way, making use of the different reactivity of the hydroxyl groups in alkylation and stannylation reactions. In addition, the deoxyfluoro derivatives of 1 at positions, 6,3',4',epi-4', and 6' have been prepared by reaction of the appropriate substrates with diethylaminosulfur trifluoride or tetrabutylammonium fluoride. Finally, the 6-deoxyiodo and 6'-bromodeoxy analogues of 1 have also been prepared.

Biotic and abiotic transformations of methyl tertiary butyl ether (MTBE).

PubMed

Fischer, Axel; Oehm, Claudia; Selle, Michael; Werner, Peter

2005-11-01

Methyl tertiary butyl ether (MTBE) is a fuel additive which is used all over the world. In recent years it has often been found in groundwater, mainly in the USA, but also in Europe. Although MTBE seems to be a minor toxic, it affects the taste and odour of water at concentrations of < 30 microg/L. Although MTBE is often a recalcitrant compound, it is known that many ethers can be degraded by abiotic means. The aim of this study was to examine biotic and abiotic transformations of MTBE with respect to the particular conditions of a contaminated site (former refinery) in Leuna, Germany. Groundwater samples from wells of a contaminated site were used for aerobic and anaerobic degradation experiments. The abiotic degradation experiment (hydrolysis) was conducted employing an ion-exchange resin and MTBE solutions in distilled water. MTBE, tertiary butyl formate (TBF) and tertiary butyl alcohol (TBA) were measured by a gas chromatograph with flame ionisation detector (FID). Aldehydes and organic acids were respectively analysed by a gas chromatograph with electron capture detector (ECD) and high-performance ion chromatography (HPIC). Under aerobic conditions, MTBE was degraded in laboratory experiments. Only 4 of a total of 30 anaerobic experiments exhibited degradation, and the process was very slow. In no cases were metabolites detected, but a few degradation products (TBF, TBA and formic acid) were found on the site, possibly due to the lower temperatures in groundwater. The abiotic degradation of MTBE with an ion-exchange resin as a catalyst at pH 3.5 was much faster than hydrolysis in diluted hydrochloric acid (pH 1.0). Although the aerobic degradation of MTBE in the environment seems to be possible, the specific conditions responsible are widely unknown. Successful aerobic degradation only seems to take place if there is a lack of other utilisable compounds. However, MTBE is often accompanied by other fuel compounds on contaminated sites and anaerobic conditions

Research in acetylene containing monomers

NASA Technical Reports Server (NTRS)

Ogliaruso, M. A.

1976-01-01

The preparation of precursor bisbenzils with pendant acetylene linkages for use in the synthesis of new aromatic poly (phenyl quinoxalines) was investigated. Attempts to condense para, para prime-dibromo benzil and potassium acetylide in liquid ammonia and in toluene, to prepare 4-phenyl acetyl phenyl ether, 4-(paraacetylphenyl) acetyl phenyl ether, 4-phenyl acetyl-4 primeacetyl phenyl acetyl phenyl ether, the reaction of 4-phenyl acetyl phenyl ether with Villsmeier reagent to prepare 4-(beta-chloro cinnamaldehyde) phenyl ether, the reaction of 4-(para-acetyl phenyl) acetyl phenyl ether with Villsmeier reagent, and the oxidation of bibenzil to prepare benzil are described. The reactions of phenyl acetylene with oxidizing agent, of phenyl acetylene with bromine, of 1,1,2,2-tetrabromo ethyl benzene with zinc and with oxidizing agent are described.

MEASUREMENT OF EXHALED BREATH AND VENOUS BLOOD TO DEVELOP A PHYSIOLOGICALLY BASED PHARMACOKINETIC MODEL FOR HUMAN EXPOSURE TO METHYL TERTIARY-BUTYL ETHER AND THE PRODUCTION OF THE BIOMARKER TERTIARY-BUTYL ALCOHOL

EPA Science Inventory

Methyl tertiary-butyl ether (MTBE) is a common fuel additive used to increase the availability of oxygen in gasoline to reduce winter-time carbon monoxide emissions from automobiles. Also, MTBE boosts gasoline "octane" rating and, as such, allows reduction of benzene...

Discovery of 5-substituted tetrahydronaphthalen-2yl-methyl with N-phenyl-N-(piperidin-4-yl)propionamide derivatives as potent opioid receptor ligands.

PubMed

Deekonda, Srinivas; Wugalter, Lauren; Kulkarni, Vinod; Rankin, David; Largent-Milnes, Tally M; Davis, Peg; Bassirirad, Neemah M; Lai, Josephine; Vanderah, Todd W; Porreca, Frank; Hruby, Victor J

2015-09-15

A new series of novel opioid ligands have been designed and synthesized based on the 4-anilidopiperidine scaffold containing a 5-substituted tetrahydronaphthalen-2yl)methyl group with different N-phenyl-N-(piperidin-4-yl)propionamide derivatives to study the biological effects of these substituents on μ and δ opioid receptor interactions. Recently our group reported novel 4-anilidopiperidine analogues, in which several aromatic ring-contained amino acids were conjugated with N-phenyl-N-(piperidin-4-yl)propionamide and examined their biological activities at the μ and δ opioid receptors. In continuation of our efforts in these novel 4-anilidopiperidine analogues, we took a peptidomimetic approach in the present design, in which we substituted aromatic amino acids with tetrahydronaphthalen-2yl methyl moiety with amino, amide and hydroxyl substitutions at the 5th position. In in vitro assays these ligands, showed very good binding affinity and highly selective toward the μ opioid receptor. Among these, the lead ligand 20 showed excellent binding affinity (2 nM) and 5000 fold selectivity toward the μ opioid receptor, as well as functional selectivity in GPI assays (55.20 ± 4.30 nM) and weak or no agonist activities in MVD assays. Based on the in vitro bioassay results the lead compound 20 was chosen for in vivo assessment for efficacy in naïve rats after intrathecal administration. Compound 20 was not significantly effective in alleviating acute pain. This discrepancy between high in vitro binding affinity, moderate in vitro activity, and low in vivo activity may reflect differences in pharmacodynamics (i.e., engaging signaling pathways) or pharmacokinetics (i.e., metabolic stability). In sum, our data suggest that further optimization of this compound 20 is required to enhance in vivo activity. Copyright © 2015 Elsevier Ltd. All rights reserved.

Nimodipine, an L-type calcium channel blocker attenuates mitochondrial dysfunctions to protect against 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced Parkinsonism in mice.

PubMed

Singh, Alpana; Verma, Poonam; Balaji, Gillela; Samantaray, Supriti; Mohanakumar, Kochupurackal P

2016-10-01

Parkinson's disease (PD), the most common progressive neurodegenerative movement disorder, results from loss of dopaminergic neurons of substantia nigra pars compacta. These neurons exhibit Cav1.3 channel-dependent pacemaking activity. Epidemiological studies suggest reduced risk for PD in population under long-term antihypertensive therapy with L-type calcium channel antagonists. These prompted us to investigate nimodipine, an L-type calcium channel blocker for neuroprotective effect in cellular and animal models of PD. Nimodipine (0.1-10 μM) significantly attenuated 1-methyl-4-phenyl pyridinium ion-induced loss in mitochondrial morphology, mitochondrial membrane potential and increases in intracellular calcium levels in SH-SY5Y neuroblastoma cell line as measured respectively employing Mitotracker green staining, TMRM, and Fura-2 fluorescence, but only a feeble neuroprotective effect was observed in MTT assay. Nimodipine dose-dependently reduced 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced parkinsonian syndromes (akinesia and catalepsy) and loss in swimming ability in Balb/c mice. It attenuated MPTP-induced loss of dopaminergic tyrosine hydroxylase positive neurons in substantia nigra, improved mitochondrial oxygen consumption and inhibited reactive oxygen species production in the striatal mitochondria measured using dichlorodihydrofluorescein fluorescence, but failed to block striatal dopamine depletion. These results point to an involvement of L-type calcium channels in MPTP-induced dopaminergic neuronal death in experimental parkinsonism and more importantly provide evidences for nimodipine to improve mitochondrial integrity and function. Copyright © 2016 Elsevier Ltd. All rights reserved.

Conformational Study of Dibenzyl Ether

NASA Astrophysics Data System (ADS)

Hernandez-Castillo, Alicia O.; Abeysekera, Chamara; Hewett, Daniel M.; Zwier, Timothy S.

2017-06-01

Understanding the initial stages of polycyclic aromatic hydrocarbon (PAH) aggregation, the onset of soot formation, is an important goal on the pathway to cleaner combustion processes. PAHs with short alkyl chains, present in fuel-rich combustion environments, can undergo reactions that will chemically link aromatic rings together. One such example of a linked diaryl compound is dibenzyl ether, C_{6}H_{5}-CH_{2}-O-CH_{2}-C_{6}H_{5}. The -CH_{2}-O-CH_{2}- linkage has a length and flexibility well-suited to forming a π-stacked conformation between the two phenyl rings. In this talk, we will explore the single-conformation spectroscopy of dibenzyl ether under jet-cooled conditions in the gas phase. Laser-induced fluorescence, chirped pulse Fourier transform microwave (8-18 GHz region), and single-conformation infrared spectroscopy in the alkyl CH stretch region were all carried out on the molecule, thereby interrogating its full array of electronic, vibrational and rotational degrees of freedom. This work is the first step in a broader study to determine the extent of π-stacking in linked aryl compounds as a function of linkage and PAH size.

DPPC/poly(2-methyl-2-oxazoline)-grad-poly(2-phenyl-2-oxazoline) chimeric nanostructures as potential drug nanocarriers

NASA Astrophysics Data System (ADS)

Pippa, Natassa; Kaditi, Eleni; Pispas, Stergios; Demetzos, Costas

2013-06-01

In this study, we report on the self assembly behavior and on stability studies of mixed (chimeric) nanosystems consisting of dipalmitoylphosphatidylcholine (DPPC) and poly(2-methyl-2-oxazoline)-grad-poly(2-phenyl-2-oxazoline) (MPOx) gradient copolymer in aqueous media and in fetal bovine serum (FBS). A gamut of light scattering techniques and fluorescence spectroscopy were used in order to extract information on the size and morphological characteristics of the nanoassemblies formed, as a function of gradient block copolymer content, as well as temperature. The hydrodynamic radii ( R h) of nanoassemblies decreased in the process of heating up to 50 °C, while the fractal dimension ( d f) values, also increased. Indomethacin was successfully incorporated into these chimeric nanocarriers. Drug release was depended on the components ratio. The present studies show that there are a number of parameters that can be used in order to alter the properties of chimeric nanosystems, and this is advantageous to the development of "smart" nanocarriers for drug delivery.

Evaluation of thermal gelation behavior of different cellulose ether polymers by rheology

NASA Astrophysics Data System (ADS)

Balaghi, S.; Edelby, Y.; Senge, B.

2014-05-01

Hydroxypropylmethylcellulose (HPMC) and Methylcellulose (MC) are cellulose ethers which can be dispersed in water and used as thickeners, emulsifiers, binders, film formers, and water-retention agents due to their hydrophilic and hydrophobic characteristics. In this study, various types of HPMCs, in comparison with two types of MCs were examined. The formed gels of the different cellulose ethers showed specific and various structural formation and network properties. The degree of methylation (Meth.) and hydroxypropylation (HyPr.) affected drastically the heat-induced gelation of the examined cellulose ethers.

Carcinogenicity of methyl-tertiary butyl ether in gasoline.

PubMed

Mehlman, Myron A

2002-12-01

Methyl tertiary butyl ether (MTBE) was added to gasoline on a nationwide scale in 1992 without prior testing of adverse, toxic, or carcinogenic effects. Since that time, numerous reports have appeared describing adverse health effects of individuals exposed to MTBE, both from inhalation of fumes in the workplace and while pumping gasoline. Leakage of MTBE, a highly water-soluble compound, from underground storage tanks has led to contamination of the water supply in many areas of the United States. Legislation has been passed by many states to prohibit the addition of MTBE to gasoline. The addition of MTBE to gasoline has not accomplished its stated goal of decreasing air pollution, and it has posed serious health risks to a large portion of the population, particularly the elderly and those with respiratory problems, asthma, and skin sensitivity. Reports of animal studies of carcinogenicity of MTBE began to appear in the 1990s, prior to the widespread introduction of MTBE into gasoline. These reports were largely ignored. In ensuing years, further studies have shown that MTBE causes various types of malignant tumors in mice and rats. The National Toxicology Program (NTP) Board of Scientific Counselors' Report on Carcinogens Subcommittee met in December 1998 to consider listing MTBE as "reasonably anticipated to be a human carcinogen." In spite of recommendations from Dr. Bailer, the primary reviewer, and other scientists on the committee, the motion to list MTBE in the report was defeated by a six to five vote, with one abstention. On the basis of animal studies, it is widely accepted that if a chemical is carcinogenic in appropriate laboratory animal test systems, it must be treated as though it were carcinogenic in humans. In the face of compelling evidence, NTP Committee members who voted not to list MTBE as "reasonably anticipated to be a human carcinogen" did a disservice to the general public; this action may cause needless exposure of many to health risks

[Effect of methyl tertiary butyl ether on the expression of proto-oncogenes and function genes].

PubMed

Zhou, W; Huang, G; Zhang, H

1999-05-30

Methyl tertiary butyl ether (MTBE) is a new gasoline additive, which is used to increase the combustion of gasoline and to reduce the emission of harmful exhaust from automobile. The mechanism for the carcinogenesis of MTBE in animals is not clear. Immunohistochemistry method was used to detect the effect of MTBE on the expression of c-myc and p21 proteins in NIH3T3 cells. Dot hybridization method was used to explore the expression of c-myc gene and GST-P(glutathione S-transferase-P) gene in the of MTBE treated rats. The results showed that MTBE could enhance the expression of c-myc protein, but had no effect on p21 protein. MTBE could induce high expression of c-myc gene, and had no effect on the expression of GST-P gene. These results suggest that the high expression of c-myc gene induced by MTBE might be one of the mechanisms of its carcinogenicity in animal.

Molecular modeling of the inhibition of enzyme PLA2 from snake venom by dipyrone and 1-phenyl-3-methyl-5-pyrazolone

NASA Astrophysics Data System (ADS)

Silva, S. L. Da; Comar, M., Jr.; Oliveira, K. M. T.; Chaar, J. S.; Bezerra, E. R. M.; Calgarotto, A. K.; Baldasso, P. A.; Veber, C. L.; Villar, J. A. F. P.; Oliveira, A. R. M.; Marangoni, S.

Phospholipases A2 (PLA2) are enzymes that trigger the degradation cascade of the arachidonic acid, leading to the formation of pro-inflammatory eicosanoids. The selective inhibition of PLA2s is crucial in the search for a more efficient anti-inflammatory drug with fewer side effects than the drugs currently used. Hence, we studied the influences caused by two pyrazolonic inhibitors: dipyrone (DIP) and 1-phenyl-3-methyl-5-pyrazolone (PMP) on the kinetic behavior of PLA2 from Crotalus adamanteus venom. Molecular modeling results, by DFT and MM approaches, showed that DIP is strongly associated to the active site of PLA2 through three hydrogen bonds, whereas PMP is associated to the enzyme just through hydrophobic interactions. In addition, only PMP presents an intramolecular hydrogen bond that make difficult the formation of more efficient interactions with PLA2. These results help in the understanding of the experimental observations. Experimentally, the results showed that PLA2 from C. adamanteus present a typical Michaelian behavior. In addition, the calculated kinetic parameters showed that, in the presence of DIP or PMP, the maximum enzymatic velocity (VMAX) value was kept constant, whereas the Michaelis constant (KM) values increased and the inhibition constant (KI) decreased, indicating competitive inhibition. These results show that the phenyl-pyrazolonic structures might help in the development and design of new drugs able to selectively inhibit PLA2.

Halogen lamp experiment, HALEX

NASA Technical Reports Server (NTRS)

Schmitt, G.; Stapelmann, J.

1986-01-01

The main purpose of the Halogen Lamp Experiment (HALEX) was to investigate the operation of a halogen lamp during an extended period in a microgravity environment and to prove its behavior in space. The Mirror Heating Facilities for Crystal Growth and Material Science Experiments in space relies on one or two halogen lamps as a furnace to melt the specimens. The HALEX aim is to verify: full power operation of a halogen lamp for a period of about 60 hours; achievement of about 10% of its terrestrial life span; and operation of the halogen lamp under conditions similar to furnace operation.

Adsorption of Methyl Tertiary Butyl Ether on Granular Zeolites: Batch and Column Studies

PubMed Central

Abu-Lail, Laila; Bergendahl, John A.; Thompson, Robert W.

2010-01-01

Methyl tertiary butyl ether (MTBE) has been shown to be readily removed from water with powdered zeolites, but the passage of water through fixed beds of very small powdered zeolites produces high friction losses not encountered in flow through larger sized granular materials. In this study, equilibrium and kinetic adsorption of MTBE onto granular zeolites, a coconut shell granular activated carbon (CS-1240), and a commercial carbon adsorbent (CCA) sample was evaluated. In addition, the effect of natural organic matter (NOM) on MTBE adsorption was evaluated. Batch adsorption experiments determined that ZSM-5 was the most effective granular zeolite for MTBE adsorption. Further equilibrium and kinetic experiments verified that granular ZSM-5 is superior to CS-1240 and CCA in removing MTBE from water. No competitive-adsorption effects between NOM and MTBE were observed for adsorption to granular ZSM-5 or CS-1240, however there was competition between NOM and MTBE for adsorption onto the CCA granules. Fixed-bed adsorption experiments for longer run times were performed using granular ZSM-5. The bed depth service time model (BDST) was used to analyze the breakthrough data. PMID:20153106

Concentrations and variability of organophosphate esters, halogenated flame retardants, and polybrominated diphenyl ethers in indoor and outdoor air in Stockholm, Sweden.

PubMed

Wong, Fiona; de Wit, Cynthia A; Newton, Seth R

2018-05-10

We investigated the concentrations and temporal variability of organophospate esters (OPEs), halogenated flame retardants (HFRs) and polybrominated diphenyl ethers (PBDEs) in indoor and outdoor urban air in Stockholm, Sweden over one year (2014-2015) period. The median concentrations of the three target chemical groups (OPEs, HFRs, PBDEs) were 1-2 orders of magnitude higher in indoor air than outdoor urban air. OPEs were the most abundant target FRs with median concentrations in indoor (Σ 10 OPE = 340 000 pg/m 3 ) and outdoor urban (Σ 10 OPEs = 3100 pg/m 3 ) air, being 3 orders of magnitude greater than for HFRs in indoor (Σ 15 HFRs = 120 pg/m 3 ) and outdoor urban (Σ 15 HFRs = 1.6 pg/m 3 ) air. In indoor air, PBDE concentrations (Σ 17 PBDEs = 33 pg/m 3 ) were lower than for the HFRs, but in outdoor urban air, concentrations (Σ 17 PBDEs = 1.1 pg/m 3 ) were similar to HFRs. The most abundant OPEs in both the indoor and outdoor urban air were tris(2-butoxyethyl)phosphate (TBOEP), tris(chloroisopropyl)phosphate (TCIPP), tris(2-chloroethyl)phosphate (TCEP), tri-n-butyl-phosphate (TnBP), triphenyl phosphate (TPhP) and tris(1,3-dichloroisopropyl)phosphate (TDCIPP). TCIPP in indoor air was found in the highest concentrations and showed the greatest temporal variability, which ranged from 85 000 to 1 900 000 pg/m 3 during the one-year sampling period. We speculate that activities in the building, e.g. floor cleaning, polishing, construction, introduction of new electronics and changes in ventilation rate could explain its variation. Some OPEs (TnBP, TCEP, TCIPP, TDCIPP and TPhP), HFRs/PBDEs (pentabromotoluene, 2, 3-dibromopropyl 2, 4, 6-tribromophenyl ether, hexabromobenzene, BDE-28, -47, and -99) in outdoor urban air showed seasonality, with increased concentrations during the warm period (p < 0.05, Pearson's r ranged from -0.45 to -0.91). The observed seasonality for OPEs was probably due to changes in primary

Data on the synthesis and mechanical characterization of polysiloxane-based urea-elastomers prepared from amino-terminated polydimethylsiloxanes and polydimethyl-methyl-phenyl-siloxane-copolymers.

PubMed

Riehle, Natascha; Götz, Tobias; Kandelbauer, Andreas; Tovar, Günter E M; Lorenz, Günter

2018-06-01

This article contains data on the synthesis and mechanical characterization of polysiloxane-based urea-elastomers (PSUs) and is related to the research article entitled "Influence of PDMS molecular weight on transparency and mechanical properties of soft polysiloxane-urea-elastomers for intraocular lens application" (Riehle et al., 2018) [1]. These elastomers were prepared by a two-step polyaddition using the aliphatic diisocyanate 4,4'-Methylenbis(cyclohexylisocyanate) (H 12 MDI), a siloxane-based chain extender 1,3-Bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane (APTMDS) and amino-terminated polydimethylsiloxanes (PDMS) or polydimethyl-methyl-phenyl-siloxane-copolymers (PDMS-Me,Ph), respectively. (More details about the synthesis procedure and the reaction scheme can be found in the related research article (Riehle et al., 2018) [1]). Amino-terminated polydimethylsiloxanes with varying molecular weights and PDMS-Me,Ph-copolymers were prepared prior by a base-catalyzed ring-chain equilibration of a cyclic siloxane and the endblocker APTMDS. This DiB article contains a procedure for the synthesis of the base catalyst tetramethylammonium-3-aminopropyl-dimethylsilanolate and a generic synthesis procedure for the preparation of a PDMS having a targeted number average molecular weight M ¯ n of 3000 g mol -1 . Molecular weights and the amount of methyl-phenyl-siloxane within the polysiloxane-copolymers were determined by 1 H NMR and 29 Si NMR spectroscopy. The corresponding NMR spectra and data are described in this article. Additionally, this DiB article contains processed data on in line and off line FTIR-ATR spectroscopy, which was used to follow the reaction progress of the polyaddition by showing the conversion of the diisocyanate. All relevant IR band assignments of a polydimethylsiloxane-urea spectrum are described in this article. Finally, data on the tensile properties and the mechanical hysteresis-behaviour at 100% elongation of PDMS-based polyurea

The Halogen Bond

PubMed Central

2016-01-01

The halogen bond occurs when there is evidence of a net attractive interaction between an electrophilic region associated with a halogen atom in a molecular entity and a nucleophilic region in another, or the same, molecular entity. In this fairly extensive review, after a brief history of the interaction, we will provide the reader with a snapshot of where the research on the halogen bond is now, and, perhaps, where it is going. The specific advantages brought up by a design based on the use of the halogen bond will be demonstrated in quite different fields spanning from material sciences to biomolecular recognition and drug design. PMID:26812185

Broadband gain in poly(3-hexylthiophene):phenyl-C{sub 61}-butyric-acid-methyl-ester photodetectors enabled by a semicontinuous gold interlayer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Melancon, Justin M.; Živanović, Sandra R., E-mail: sz@latech.edu

2014-10-20

Substantial broadband photoconductive gain has been realized for organic, thin-film photodetectors with a poly(3-hexylthiophene):phenyl-C{sub 61}-butyric-acid-methyl-ester (P3HT:PCBM) active layer at low bias voltages. External quantum efficiencies upwards of 1500% were achieved when a semicontinuous gold layer was introduced at the anode interface. Significant gain was also observed in the sub-band gap, near infrared region where the external quantum efficiency approached 100% despite the lack of a sensitizer. The gain response was highly dependent on the thickness of the active layer of the photodetector with the best results achieved with the thinnest devices. The gain is the result of the injection ofmore » secondary electrons due to hole charge trapping at the semicontinuous gold layer.« less

Development of a category approach to predict the testicular toxicity of chemical substances structurally related to ethylene glycol methyl ether.

PubMed

Yamada, Takashi; Tanaka, Yushiro; Hasegawa, Ryuichi; Sakuratani, Yuki; Yamazoe, Yasushi; Ono, Atsushi; Hirose, Akihiko; Hayashi, Makoto

2014-12-01

We propose a category approach to assessing the testicular toxicity of chemicals with a similar structure to ethylene glycol methyl ether (EGME). Based on toxicity information for EGME and related chemicals and accompanied by adverse outcome pathway information on the testicular toxicity of EGME, this category was defined as chemicals that are metabolized to methoxy- or ethoxyacetic acid, a substance responsible for testicular toxicity. A Japanese chemical inventory was screened using the Hazard Evaluation Support System, which we have developed to support a category approach for predicting the repeated-dose toxicity of chemical substances. Quantitative metabolic information on the related chemicals was then considered, and seventeen chemicals were finally obtained from the inventory as a shortlist for the category. Available data in the literature shows that chemicals for which information is available on the metabolic formation of EGME, ethylene glycol ethyl ether, methoxy- or ethoxyacetic acid do in fact possess testicular toxicity, suggesting that testicular toxicity is a concern, due to metabolic activation, for the remaining chemicals. Our results clearly demonstrate practical utility of AOP-based category approach for predicting repeated-dose toxicity of chemicals. Copyright © 2014 Elsevier Inc. All rights reserved.

Jet-cooled electronic and vibrational spectroscopy of crown ethers: benzo-15-crown-5 ether and 4'-amino-benzo-15-crown-5 ether.

PubMed

Shubert, V Alvin; James, William H; Zwier, Timothy S

2009-07-16

Laser-induced fluorescence (LIF), ultraviolet hole-burning (UVHB), and resonant ion-dip infrared (RIDIR) spectroscopies were carried out on isolated benzo-15-crown-5 ether (B15C) and 4'-amino-benzo-15-crown-5 ether (ABC) cooled in a supersonic expansion. Three conformational isomers of B15C and four of ABC were observed and spectroscopically characterized. Full optimizations and harmonic frequency calculations were undertaken for the full set of almost 1700 conformational minima identified in a molecular mechanics force field search. When compared with TDDFT predictions, the S(0)-S(1) origin positions serve as a useful diagnostic of the conformation of the crown ether near the phenyl ring responsible for the UV absorption and to the position of the NH(2) substituent. In-plane orientations for the beta carbons produce red-shifted S(0)-S(1) origins, while out-of-plane "buckling" produces substantial blue shifts of 600 cm(-1) or more. Comparison between the alkyl CH stretch spectra of B15C and ABC divide the spectra into common subgroups shared by the two molecules. The high-frequency CH stretch transitions (above 2930 cm(-1)) reflect the number of CH...O interactions, which in turn track in a general way the degree of buckling of the crown. On this basis, assignments of each of the observed conformational isomers to a class of structure can be made. All the observed structures have some degree of buckling to them, indicating that in the absence of a strong-binding partner, the crown folds in on itself to gain additional stabilization from weak dispersive and CH...O interactions.

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

PubMed

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

2013-07-01

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

Sleep-inducing N-alkyl-5-[m-(trifluoromethyl)phenyl]-5-hydroxy-2-pyrrolidinones and N-alkyl-3-(trifluoromethyl)cinnamamides.

PubMed

Houlihan, W J; Gogerty, J H; Ryan, E A; Schmitt, G

1985-01-01

A series of N-alkyl-3-[m-(trifluoromethyl)phenyl]-5-hydroxy-2-pyrrolidinones and N-alkyl-3-(trifluoromethyl)-cinnamamides were prepared and screened in a series of tests designed to detect potential sleep inducers. The more active members of the series were evaluated for their ability to induce sleep in Cebus monkeys. The most active compound, N-methyl-5-[m-(trifluoromethyl)phenyl]-5-hydroxy-2-pyrrolidinone, was equal to methaqualone.

Top-Contact Pentacene-Based Organic Thin Film Transistor (OTFT) with N, N'-Bis(3-Methyl Phenyl)- N, N'-Diphenyl Benzidine (TPD)/Au Bilayer Source-Drain Electrode

NASA Astrophysics Data System (ADS)

Borthakur, Tribeni; Sarma, Ranjit

2018-01-01

A top-contact Pentacene-based organic thin film transistor (OTFT) with N, N'-Bis (3-methyl phenyl)- N, N'-diphenyl benzidine (TPD)/Au bilayer source-drain electrode is reported. The devices with TPD/Au bilayer source-drain (S-D) electrodes show better performance than the single layer S-D electrode OTFT devices. The field-effect mobility of 4.13 cm2 v-1 s-1, the on-off ratio of 1.86 × 107, the threshold voltage of -4 v and the subthreshold slope of .27 v/decade, respectively, are obtained from the device with a TPD/Au bilayer source-drain electrode.

Poly(vinyl methyl ether/maleic anhydride)-Doped PEG-PLA Nanoparticles for Oral Paclitaxel Delivery To Improve Bioadhesive Efficiency.

PubMed

Wang, Qian; Li, Chan; Ren, Tianyang; Chen, Shizhu; Ye, Xiaoxia; Guo, Hongbo; He, Haibing; Zhang, Yu; Yin, Tian; Liang, Xing-Jie; Tang, Xing

2017-10-02

Bioadhesive nanoparticles based on poly(vinyl methyl ether/maleic anhydride) (PVMMA) and poly(ethylene glycol) methyl ether-b-poly(d,l-lactic acid) (mPEG-b-PLA) were produced by the emulsification solvent evaporation method. Paclitaxel was utilized as the model drug, with an encapsulation efficiency of up to 90.2 ± 4.0%. The nanoparticles were uniform and spherical in shape and exhibited a sustained drug release compared with Taxol. m-NPs also exhibited favorable bioadhesive efficiency at the same time. Coumarin 6 or DiR-loaded nanoparticles with/without PVMMA (C6-m-NPs/DiR-m-NPs or C6-p-NPs/DiR-p-NPs) were used for cellular uptake and intestinal adhesion experiments, respectively. C6-m-NPs were shown to enhance cellular uptake, and caveolae/lipid raft mediated endocytosis was the primary route for the uptake of the nanoparticles. Favorable bioadhesive efficiency led to prolonged retention in the intestine reflected by the fluorescence in isolated intestines ex vivo. In a ligated intestinal loops model, C6-m-NPs showed a clear advantage for transporting NPs across the mucus layer over C6-p-NPs and free C6. The apparent permeability coefficient (Papp) of PTX-m-NPs through Caco-2/HT29 monolayers was 1.3- and 1.6-fold higher than PTX-p-NPs and Taxol, respectively, which was consistent with the AUC 0-t of different PTX formulations after oral administration in rats. PTX-m-NPs also exhibited a more effective anticancer efficacy, with an IC 50 of 0.2 ± 1.4 μg/mL for A549 cell lines, further demonstrating the advantage of bioadhesive nanoparticles. The bioadhesive nanoparticles m-NPs demonstrated both mucus permeation and epithelial absorption, and thus, this bioadhesive drug delivery system has the potential to improve the bioavailability of drugs that are insoluble in the gastrointestinal environment.

Analysis of hydroquinone and some of its ethers by using capillary electrochromatography.

PubMed

Desiderio, C; Ossicini, L; Fanali, S

2000-07-28

Capillary electrochromatography (CEC) was used for the analysis of relevant compounds in cosmetic preparation. Hydroquinone (HQ) and some of its ethers (methyl-, dimethyl-, benzyl-, phenyl-, propyl-HQ derivatives) were analyzed by using an octadecylsilica (ODS) stationary phase packed in fused-silica capillary (100 microm I.D.; 30 cm and 21.5 cm total and effective lengths, respectively). 20 mM Ammonium acetate pH 6-acetonitrile (50-70%) were the mobile phases used for the experiments. The acetonitrile (ACN) content strongly influenced the resolution of the studied compounds as well as the efficiency and the retention factor. Baseline resolution for the studied analytes was achieved at both the lowest and the highest percentage of ACN, the last one providing the shortest analysis time. Mobile phase containing 70% of ACN was therefore used for the analysis of an extract of skin-toning cream declared to contain HQ. Good repeatability of both retention times, peak areas and peak areas ratio (Asample/Ainternational standard) was found. The calibration graphs were linear in the concentration range studied (5-90 microg/ml) with correlation coefficients between 0.9975 and 09991. The analysis of the cosmetic preparation revealed the presence of HQ (1.72%, w/w) and of two additional peaks (not identified).

Di(phenylpropylamino)gossypol: a derivative of the dimeric natural product gossypol

USDA-ARS?s Scientific Manuscript database

Di(phenylpropylamino)gossypol [2,2'-bis(1,6-dihydroxy,-5-isopropyl,-8-methineaminopropylbenzene-3-methyl)-naphthylene-7-one, C48H52N2O6] is formed by reaction of the dimeric natural product gossypol with 3-phenyl-1-propylamine. When crystallized from diethyl ether, the compound has monoclinic (P21/c...

Halogenation of microcapsule walls

NASA Technical Reports Server (NTRS)

Davis, T. R.; Schaab, C. K.; Scott, J. C.

1972-01-01

Procedure for halogenation of confining walls of both gelatin and gelatin-phenolic resin capsules is similar to that used for microencapsulation. Ten percent halogen content renders capsule wall nonburning; any higher content enhances flame-retardant properties of selected internal phase material. Halogenation decreases permeability of wall material to encapsulated materials.

A facile approach towards increasing the nitrogen-content in nitrogen-doped carbon nanotubes via halogenated catalysts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ombaka, L.M.; Ndungu, P.G.; Department of Applied Chemistry, Doornfontein Campus, University of Johannesburg, P.O. Box 17011, Johannesburg 2028

Nitrogen-doped carbon nanotubes (N-CNTs) have been synthesized at 850 °C via a CVD deposition technique by use of three ferrocenyl derivative catalysts, i.e. para-CN, -CF{sub 3} and -Cl substituted-phenyl rings. The synthesized catalysts have been characterized by NMR, IR, HR-MS and XRD. The XRD analysis of the para-CF{sub 3} catalyst indicates that steric factors influence the X-ray structure of 1,1′-ferrocenylphenyldiacrylonitriles. Acetonitrile or pyridine was used as carbon and nitrogen sources to yield mixtures of N-CNTs and carbon spheres (CS). The N-CNTs obtained from the para-CF{sub 3} catalysts, in pyridine, have the highest nitrogen-doping level, show a helical morphology and aremore » less thermally stable compared with those synthesized by use of the para-CN and -Cl as catalyst. This suggests that fluorine heteroatoms enhance nitrogen-doping in N-CNTs and formation of helical-N-CNTs (H-N-CNTs). The para-CF{sub 3} and para-Cl catalysts in acetonitrile yielded iron-filled N-CNTs, indicating that halogens promote encapsulation of iron into the cavity of N-CNT. The use of acetonitrile, as carbon and nitrogen source, with the para-CN and -Cl as catalysts also yielded a mixture of N-CNTs and carbon nanofibres (CNFs), with less abundance of CNFs in the products obtained using para-Cl catalysts. However, para-CF{sub 3} catalyst in acetonitrile gave N-CNTs as the only shaped carbon nanomaterials. - Graphical abstract: Graphical abstract showing the synthesis of N-CNTs using halogenated-ferrocenyl derivatives as catalyst with pyridine or acetonitrile as nitrogen and carbon sources via the chemical vapour deposition technique. - Highlights: • N-CNTs were synthesized from halogenated ferrocenyl catalysts. • Halogenated catalysts promote nitrogen-doping and pyridinic nitrogen in N-CNTs. • Halogenated catalysts facilitate iron filling of N-CNTs.« less

Spectrofluorimetric determination of DL-N-methyl-3-phenyl-3-[(α,α,α-trifluoro-p-tolyl)oxy]propylamine in pharmaceuticals and chitosan solution.

PubMed

Rodrigues, Máira Regina

2012-02-01

A spectrofluorimetric method for the determination of D,L-N-methyl-3-phenyl-3-[(α,α,α-trifluoro-p-tolyl)oxy]propylamine, fluoxetine (F), in pharmaceuticals was evaluated in the 50.0-500.0 μg ml⁻¹ range. Linearity, sensibility, quantification and detection limit, and precision values are satisfactory. The method does not need pre-treatment and was successfully applied to the determination in pharmaceuticals and chitosan (Ch) solution. Ch has an ability to carry and absorb fat and may eventually be used together with F in slimming diets, and then interactions of Ch-F may occur. This work seeks to study these interactions by monitoring the photophysics of a drug in the presence of Ch. The results warn about the care that must be taken when both compounds are prescribed together.

Crystal structure of bis-(N-methyl-N-phenyl-amino)-tris-ulfane.

PubMed

Barany, George; Henley, Matthew J; Polski, Lauren A; Schroll, Alayne L; Young, Victor G

2015-07-01

The title compound, C14H16N2S3, crystallized with two independent mol-ecules [(1 a ) and (1 b )] in the asymmetric unit. Both mol-ecules display a pseudo-trans conformation. The two consecutive S-S bond lengths of the tris-ulfane unit of mol-ecule (1 a ) are 2.06 (3) and 2.08 (3) Å, and 2.08 (3) and 2.07 (2) Å for mol-ecule (1 b ). Torsion angles about each of the two S-S bonds are 86.6 (2) and 87.0 (2)° for (1 a ), and -84.6 (2) and -85.9 (2)° for (1 b ). The core atoms, viz. the N-S-S-S-N moiety, of the two mol-ecules superimpose well if one is inverted on the other, but the phenyl groups do not. Thus, the two units are essentially conformational enanti-omers. In mol-ecule (1 a ), the two phenyl rings are inclined to one another by 86.7 (3)°, and in mol-ecule (1 b ), by 81.1 (3)°. In the crystal, mol-ecules are linked via C-H⋯π inter-actions, forming sheets lying parallel to (010).

Biodegradation of methyl t-butyl ether by aerobic granules under a cosubstrate condition.

PubMed

Zhang, L L; Chen, J M; Fang, F

2008-03-01

Aerobic granules efficient at degrading methyl tert-butyl ether (MTBE) with ethanol as a cosubstrate were successfully developed in a well-mixed sequencing batch reactor (SBR). Aerobic granules were first observed about 100 days after reactor startup. Treatment efficiency of MTBE in the reactor during stable operation exceeded 99.9%, and effluent MTBE was in the range of 15-50 microg/L. The specific MTBE degradation rate was observed to increase with increasing MTBE initial concentration from 25 to 500 mg/L, which peaked at 22.7 mg MTBE/g (volatile suspended solids).h and declined with further increases in MTBE concentration as substrate inhibition effects became significant. Microbial-community deoxyribonucleic acid profiling was carried out using denaturing gradient gel electrophoresis of polymerase chain reaction-amplified 16S ribosomal ribonucleic acid. The reactor was found to be inhabited by several diverse bacterial species, most notably microorganisms related to the genera Sphingomonas, Methylobacterium, and Hyphomicrobium vulgare. These organisms were previously reported to be associated with MTBE biodegradation. A majority of the bands in the reactor represented a group of organisms belonging to the Flavobacteria-Proteobacteria-Actinobacteridae class of bacteria. This study demonstrates that MTBE can be effectively degraded by aerobic granules under a cosubstrate condition and gives insight into the microorganisms potentially involved in the process.

The effect of materials selection on metals reduction in propylene glycol methyl ether acetate, PGMEA

NASA Astrophysics Data System (ADS)

Entezarian, Majid; Geiger, Bob

2016-03-01

The trend in microelectronics fabrication is to produce nano-features measuring down to 10 nm and finer. The PPT levels of organic and inorganic contaminants in the photoresist, solvent and cleaning solutions are becoming a major processing variable affecting the process capability and defectivity. The photoresist usually contains gels, metals, and particulates that could interfere with the lithography process and cause microbridging defects. Nano filters of 5 nm polypropylene, 5 nm polyethylene, and 10 nm natural nylon were used to filter propylene glycol methyl ether acetate PGMEA containing 50 ppb of Na, Mg, Al, Ca, Cr, Mn, Fe, Cu, Zn, and Pb. All filters were effective in removing trivalent Al, Cr, and Fe metals indicating the mechanism for their removal as mechanical sieving. However, the nylon was also very effective in removing the divalent metals showing adsorptive properties. Furthermore, the metal removal of the nylon membrane was studied as a function of surface chemistry. Natural and charged 40 nm nylon membranes were tested and found that charged nylon is more effective for metal removal.

Anion exchange membranes based on terminally crosslinked methyl morpholinium-functionalized poly(arylene ether sulfone)s

NASA Astrophysics Data System (ADS)

Kwon, Sohyun; Rao, Anil H. N.; Kim, Tae-Hyun

2018-01-01

Azide-assisted terminal crosslinking of methyl morpholinium-functionalized poly(arylene ether sulfone) block copolymers yields products (xMM-PESs) suitable for use as anion exchange membranes. By combining the advantages of bulky morpholinium conductors and our unique polymer network crosslinked only at the termini of the polymer chains, we can produce AEMs that after the crosslinking show minimal loss in conductivity, yet with dramatically reduced water uptake. Terminal crosslinking also significantly increases the thermal, mechanical and chemical stability levels of the membranes. A high ion conductivity of 73.4 mS cm-1 and low water uptake of 26.1% at 80 °C are obtained for the crosslinked membrane with higher amount of hydrophilic composition, denoted as xMM-PES-1.5-1. In addition, the conductivity of the crosslinked xMM-PES-1.5-1 membrane exceeds that of its non-crosslinked counterpart (denoted as MM-PES-1.5-1) above 60 °C at 95% relative humidity because of its enhanced water retention capacity caused by the terminally-crosslinked structure.

Contact allergy to an epoxy reactive diluent: 1,4-butanediol diglycidyl ether.

PubMed

Jolanki, R; Estlander, T; Kanerva, L

1987-02-01

3 female workers in a brush factory developed contact allergy from a 2-component epoxy glue containing epoxy resin (37% w/w), reactive diluents: i.e., 1,4-butanediol diglycidyl ether (BDDGE) 3%, glycidyl ethers of aliphatic alcohols (Epoxide 8) 0.03% and phenyl glycidyl ether (PGE) 0.01%; and inert fillers. All 3 patients were positive to the resin component of the glue and to BDDGE, indicating that BDDGE was the main allergen. 2 of the patients reacted to PGE, but none to the 3rd reactive diluent (Epoxide 8) in the glue. 2 of the patients did not react to epoxy resin, indicating that BDDGE may be an even stronger sensitizer in humans than epoxy resin, and that it does not cross-react with epoxy resins. Permeation studies revealed that BDDGE penetrates disposable PVC and rubber gloves in less than 30 min; thus, contaminated gloves should be replaced immediately. Reactive diluents should be included in patch test series if contact allergy to epoxy products is suspected.

Antiparkinsonian effects of aqueous methanolic extract of Hyoscyamus niger seeds result from its monoamine oxidase inhibitory and hydroxyl radical scavenging potency.

PubMed

Sengupta, T; Vinayagam, J; Nagashayana, N; Gowda, B; Jaisankar, P; Mohanakumar, K P

2011-01-01

Hyoscyamus species is one of the four plants used in Ayurveda for the treatment of Parkinson's disease (PD). Since Hyoscyamus niger was found to contain negligible levels of L-DOPA, we evaluated neuroprotective potential, if any, of characterized petroleum ether and aqueous methanol extracts of its seeds in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) model of PD in mice. Air dried authenticated H. niger seeds were sequentially extracted using petroleum ether and aqueous methanol and were characterized employing HPLC-electrochemistry and LCMS. Parkinsonian mice were treated daily twice with the extracts (125-500 mg/kg, p.o.) for two days and motor functions and striatal dopamine levels were assayed. Administration of the aqueous methanol extract (containing 0.03% w/w of L-DOPA), but not petroleum ether extract, significantly attenuated motor disabilities (akinesia, catalepsy and reduced swim score) and striatal dopamine loss in MPTP treated mice. Since the extract caused significant inhibition of monoamine oxidase activity and attenuated 1-methyl-4-phenyl pyridinium (MPP+)-induced hydroxyl radical (·OH) generation in isolated mitochondria, it is possible that the methanolic extract of Hyoscyamus niger seeds protects against parkinsonism in mice by means of its ability to inhibit increased ·OH generated in the mitochondria.

Modeling of the oxidation of methyl esters—Validation for methyl hexanoate, methyl heptanoate, and methyl decanoate in a jet-stirred reactor

PubMed Central

Glaude, Pierre Alexandre; Herbinet, Olivier; Bax, Sarah; Biet, Joffrey; Warth, Valérie; Battin-Leclerc, Frédérique

2013-01-01

The modeling of the oxidation of methyl esters was investigated and the specific chemistry, which is due to the presence of the ester group in this class of molecules, is described. New reactions and rate parameters were defined and included in the software EXGAS for the automatic generation of kinetic mechanisms. Models generated with EXGAS were successfully validated against data from the literature (oxidation of methyl hexanoate and methyl heptanoate in a jet-stirred reactor) and a new set of experimental results for methyl decanoate. The oxidation of this last species was investigated in a jet-stirred reactor at temperatures from 500 to 1100 K, including the negative temperature coefficient region, under stoichiometric conditions, at a pressure of 1.06 bar and for a residence time of 1.5 s: more than 30 reaction products, including olefins, unsaturated esters, and cyclic ethers, were quantified and successfully simulated. Flow rate analysis showed that reactions pathways for the oxidation of methyl esters in the low-temperature range are similar to that of alkanes. PMID:23710076

A ring to rule them all: a cyclic ketene acetal comonomer controls the nitroxide-mediated polymerization of methacrylates and confers tunable degradability.

PubMed

Delplace, Vianney; Guégain, Elise; Harrisson, Simon; Gigmes, Didier; Guillaneuf, Yohann; Nicolas, Julien

2015-08-18

2-Methylene-4-phenyl-1,3-dioxolane (MPDL) was successfully used as a controlling comonomer in NMP with oligo(ethylene glycol) methyl ether methacrylate (MeOEGMA) to prepare well-defined and degradable PEG-based P(MeOEGMA-co-MPDL) copolymers. The level of ester group incorporation is controlled, leading to reductions in molecular weight of up to 95% on hydrolysis. Neither the polymer nor its degradation products displayed cytoxicity. The method was also successfully applied to methyl methacrylate.

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

PubMed

Farobie, Obie; Matsumura, Yukihiko

2015-09-01

In this study, biodiesel production under supercritical conditions among methanol, ethanol, and tert-butyl methyl ether (MTBE) was compared in order to elucidate the differences in their reaction behavior. A continuous reactor was employed, and experiments were conducted at various reaction temperatures (270-400 °C) and reaction times (3-30 min) and at a fixed pressure of 20 MPa and an oil-to-reactant molar ratio of 1:40. The results showed that under the same reaction conditions, the supercritical methanol method provided the highest yield of biodiesel. At 350 °C and 20 MPa, canola oil was completely converted to biodiesel after 10, 30, and 30 min in the case of - supercritical methanol, ethanol, and MTBE, respectively. The reaction kinetics of biodiesel production was also compared for supercritical methanol, ethanol, and MTBE. Copyright © 2015 Elsevier Ltd. All rights reserved.

Syntheses of halogen derivatives of L-tryptophan, L-tyrosine and L-phenylalanine labeled with hydrogen isotopes.

PubMed

Pająk, Małgorzata; Pałka, Katarzyna; Winnicka, Elżbieta; Kańska, Marianna

2016-01-01

Halogenated, labeled with tritium and doubly with deuterium and tritium, derivatives of L-tryptophan, i.e. 5'-bromo-[2-(3)H]-, 5'-bromo-[2-(2)H/(3)H]-, 5'-fluoro-[2-(3)H]-5'-fluoro-[2-(2)H/(3)H]-, 6'-fluoro-[2-(3)H]-, 6'-fluoro-[2-(2)H/(3)H]-L-tryptophan, as well as, L-tyrosine, i.e. 3'-fluoro-[2-(3)H]-, 3'-fluoro-[2-(2)H/(3)H]-, 3'-chloro-[2-(3)H]-, and 3'-chloro-[2-(2)H/(3)H]-L-tyrosine, and also L-phenylalanine, i.e. 2'-fluoro-[(3S)-(3)H]-, 2'-fluoro-[(3S)-(2)H/(3) H]-, 2'-chloro-[(3S)-(3)H]-, 2'-chloro-[(3S)-(2)H/(3)H]-, 4'-chloro-[(3S)-(3)H]-, and 4'-chloro-[(3S)-(2)H/(3)H]-L-phenylalanine were synthesized using enzymatic methods. Isotopomers of L-tryptophan were synthesized by coupling of halogenated indoles with S-methyl-L-cysteine carried out in deuteriated or tritiated incubation media. Labeled halogenated derivatives of L-tyrosine were obtained by the enzymatically supported exchange between halogenated L-tyrosine and isotopic water. Labeled halogenated isotopologues of L-Phe were synthesized by the enzymatic addition of ammonia to halogenated cinnamic acid. As a source of hydrogen tritiated water (HTO) and heavy water (D2O) with addition of HTO were used. Copyright © 2015 John Wiley & Sons, Ltd.

Organic Halogen and Related Trace Gases in the Tropical Atmosphere: Results from Recent Airborne Campaigns Over the Pacific

NASA Astrophysics Data System (ADS)

Atlas, E. L.; Navarro, M. A.; Donets, V.; Schauffler, S.; Lueb, R.; Hendershot, R.; Gabbard, S.; Hornbrook, R. S.; Apel, E. C.; Riemer, D. D.; Pan, L.; Salawitch, R. J.; Nicely, J. M.; Montzka, S. A.; Miller, B.; Moore, F. L.; Elkins, J. W.; Hintsa, E. J.; Campos, T. L.; Quack, B.; Zhu, X.; Pope, L.

2014-12-01

Organic halogen gases, especially containing bromine and iodine, play a significant role as precursors to active halogen chemistry and ozone catalytic loss. Much of the reactive organic halogen originates from biological processes in the surface ocean, which can be quite variable by season and location. The tropics and coastal margins are potentially important sources that are being examined. The recent coordinated CONTRAST/ATTREX/CAST missions were conducted in the Western Tropical Pacific, a region that is a major transport pathway for tropospheric air entering the stratosphere. One of the goals of the missions was to identify sources, distributions, and transport of organic halogens from the ocean surface into the tropical lower stratosphere. The missions were conducted during the NH winter season, Jan-Feb, 2014. In this presentation, we will discuss the distributions and variability of organic halogen gases in the study region and will examine the input of organic halogen species into the Tropical Tropopause Layer (TTL). Comparison with other tracers, such as methyl nitrate and NMHC, will help identify source regions for these gases. We will focus on the measurements obtained in the CONTRAST and ATTREX missions with data from in-situ GC/MS measurements and whole air samples collected on the NSF GV and NASA Global Hawk aircraft. Comparisons with other recent airborne campaigns, such as HIPPO and TC4, and with several ship-based studies will provide an additional context for evaluating the variability of organic halogen species in the tropical atmosphere and their role in transporting reactive halogen compounds into the UT/LS.

Synthesis, characterization and in silico designing of diethyl-3-methyl-5-(6-methyl-2-thioxo-4-phenyl-1,2,3,4-tetrahydropyrimidine-5-carboxamido) thiophene-2,4-dicarboxylate derivative as anti-proliferative and anti-microbial agents.

PubMed

Malani, Kalpesh; Thakkar, Sampark S; Thakur, Mukund Chandra; Ray, Arabinda; Doshi, Hiren

2016-10-01

A series of eight compounds diethyl-3-methyl-5-(6-methyl-2-thioxo-4-phenyl-1,2,3,4-tetrahydropyrimidine-5-carboxamido) thiophene-2,4-dicarboxilate (KM10-17) analogues have been prepared by conventional methods and characterized by IR, Mass, NMR and elemental analysis. In silico docking studies on Human topoisomerase IIbeta (PDB Id: 3QX3) have been performed for all molecules (KM10-17) synthesized. The compounds were tested for in vitro anti-proliferative activity on VERO and 786-O cell lines. Out of all the synthesized compounds, KM11 &KM16 showed moderate activity on both cell lines. In vitro anti-microbial activity was also checked against Bacillus subtilis (BS), Staphylococcus aurous (SA), Pseudomonas aeruginosa (PA), Escherichia coli (EC) and Candida albicans (CA) by well diffusion method. The compound KM11 was found to have highest zone of inhibition against BS, SA, PA and EC. The molecules KM13 and KM16 exhibited good activity against CA. The compounds KM14 and KM16 indicated good zone of inhibition against BS. Copyright © 2016 Elsevier Inc. All rights reserved.

Molecular structure impacts on secondary organic aerosol formation from glycol ethers

NASA Astrophysics Data System (ADS)

Li, Lijie; Cocker, David R.

2018-05-01

Glycol ethers, a class of widely used solvents in consumer products, are often considered exempt as volatile organic compounds based on their vapor pressure or boiling points by regulatory agencies. However, recent studies found that glycol ethers volatilize at ambient conditions nearly as rapidly as the traditional high-volatility solvents indicating the potential of glycol ethers to form secondary organic aerosol (SOA). This is the first work on SOA formation from glycol ethers. The impact of molecular structure, specifically -OH, on SOA formation from glycol ethers and related ethers are investigated in the work. Ethers with and without -OH, with methyl group hindrance on -OH and with -OH at different location are studied in the presence of NOX and under "NOX free" conditions. Photooxidation experiments under different oxidation conditions confirm that the processing of ethers is a combination of carbonyl formation, cyclization and fragmentation. Bulk SOA chemical composition analysis and oxidation products identified in both gas and particle phase suggests that the presence and location of -OH in the carbon bond of ethers determine the occurrence of cyclization mechanism during ether oxidation. The cyclization is proposed as a critical SOA formation mechanism to prevent the formation of volatile compounds from fragmentation during the oxidation of ethers. Glycol ethers with -CH2-O-CH2CH2OH structure is found to readily form cyclization products, especially with the presence of NOx, which is more relevant to urban atmospheric conditions than without NOx. Glycol ethers are evaluated as dominating SOA precursors among all ethers studied. It is estimated that the contribution of glycol ethers to anthropogenic SOA is roughly 1% of the current organic aerosol from mobile sources. The contribution of glycol ethers to anthropogenic SOA is roughly 1% of the current organic aerosol from mobile sources and will play a more important role in future anthropogenic SOA

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

PubMed

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

2010-01-01

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

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...

40 CFR 180.554 - Kresoxim-methyl; tolerances for residues.

Code of Federal Regulations, 2011 CFR

2011-07-01

... glucose conjugated); and (E)-2-[2-(4-hydroxy-2-methylphenoxy)-methyl]phenyl-2-(methoxyimido)acetic acid (free and glucose conjugated) in or on the following commodities: Commodity Parts per million Apple, dry...

40 CFR 180.554 - Kresoxim-methyl; tolerances for residues.

Code of Federal Regulations, 2010 CFR

2010-07-01

... glucose conjugated); and (E)-2-[2-(4-hydroxy-2-methylphenoxy)-methyl]phenyl-2-(methoxyimido)acetic acid (free and glucose conjugated) in or on the following commodities: Commodity Parts per million Apple, dry...

Interfacial Properties of Thin Films of Poly(vinyl ether)s with Architectural Design in Water

NASA Astrophysics Data System (ADS)

Oda, Yukari; Itagaki, Nozomi; Sugimoto, Sin; Kawaguchi, Daisuke; Matsuno, Hisao; Tanaka, Keiji

Precise design of primary structure and architecture of polymers leads to the well-defined structure, unique physical properties, and excellent functions not only in the bulk but also at the interfaces. We here constructed functional polymer interfaces in water based on the architectural design of poly(vinyl ether)s with oxyethylene side-chains (POEVE). A branched polymer with POEVE parts was preferentially segregated at the air interface in the matrix of poly(methyl methacrylate). As an alternative way to prepare the POEVE surface, the cross-linked hydrogel thin films were prepared. The moduli of the hydrogel films near the water interfaces, which were examined by force-distance curve measurements using atomic force microscopy, were greatly sensitive to the cross-linking density of the polymers. Diffuse interfaces of POEVE chains at the water interface make it possible to prevent the platelet adhesion on the films.

Is halogen content the most important factor in the removal of halogenated trace organics by MBR treatment?

PubMed

Hai, Faisal I; Tadkaew, Nichanan; McDonald, James A; Khan, Stuart J; Nghiem, Long D

2011-05-01

This study investigated the relationship between physicochemical properties (namely halogen content and hydrophobicity) of halogenated trace organics and their removal efficiencies by a laboratory scale membrane bioreactor (MBR) under stable operating conditions. The reported results demonstrated a combined effect of halogen content and hydrophobicity on the removal. Compounds with high halogen content (>0.3) were well removed (>85%) when they possessed high hydrophobicity (Log D>3.2), while those with lower Log D values were also well removed if they had low halogen content (<0.1). General indices such as the BIOWIN index (which is based on only biodegradation) or a more specific index such as the halogen content (which captures a chemical aspect) appeared insufficient to predict the removal efficiency of halogenated compounds in MBR. Experimental data confirmed that the ratio of halogen content and Log D, which incorporates two important physico-chemical properties, is comparatively more suitable. Copyright © 2011 Elsevier Ltd. All rights reserved.

Poly(methyl vinyl ether-alt-maleic acid)-functionalized porous silicon nanoparticles for enhanced stability and cellular internalization.

PubMed

Shahbazi, Mohammad-Ali; Almeida, Patrick V; Mäkilä, Ermei; Correia, Alexandra; Ferreira, Mónica P A; Kaasalainen, Martti; Salonen, Jarno; Hirvonen, Jouni; Santos, Hélder A

2014-03-01

Currently, developing a stable nanocarrier with high cellular internalization and low toxicity is a key bottleneck in nanomedicine. Here, we have developed a successful method to covalently conjugate poly(methyl vinyl ether-co-maleic acid) (PMVE-MA) copolymer on the surface of (3-aminopropyl)triethoxysilane-functionalized thermally carbonized porous silicon nanoparticles (APSTCPSi NPs), forming a surface negatively charged nanovehicle with unique properties. This polymer conjugated NPs could modify surface smoothness, charge, and hydrophilicity of the developed NPs, leading to considerable improvement in the colloidal and plasma stabilities via enhanced suspensibility and charge repulsion. Furthermore, despite the surface negative charge of the polymer-conjugated NPs, the cellular internalization was increased in both MDA-MB-231 and MCF-7 breast cancer cells. These results provide a proof-of-concept evidence that such polymer-based PSi nanocomposite can be extensively used as a promising candidate for intracellular drug delivery. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Murine motor and behavior functional evaluations for acute 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) intoxication.

PubMed

Hutter-Saunders, Jessica A L; Gendelman, Howard E; Mosley, R Lee

2012-03-01

Acute intoxication with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) induces nigrostriatal neurodegeneration that reflects Parkinson's disease (PD) pathobiology. The model is commonly used for rodent studies of PD pathogenesis and diagnostics and for developmental therapeutics. However, tests of motor function in MPTP-intoxicated mice have yielded mixed results. This unmet need reflects, in part, lesion severity, animal variability, and the overall test sensitivity and specificity. In attempts to standardize rodent motor function and behavioral tests, mice were trained on the rotarod or habituated in an open field test chamber, and baseline performance measurements were collected prior to MPTP intoxication. One week following MPTP intoxication, motor function and behavior were assessed and baseline measurements applied to post-MPTP measurements with normalization to PBS controls. Rotarod and open field tests assessed in this manner demonstrated significant differences between MPTP- and saline-treated mice, while tests of neuromuscular strength and endurance did not. We conclude that the rotarod and open field tests provide reliable measures of motor function for MPTP-intoxicated mice.

Crystal structure of 2α-(1,1-di­phenyl­eth­yl)-4-methyl-4α,5α-diphenyl-1,3-dioxolane: the result of a non-acid pinacol rearrangement

PubMed Central

Kirchner, Richard M.; Corfield, Peter W. R.; Annabi, Michelle; Regan, John; Speina, Kevin; DiProperzio, Anthony; Ciaccio, James A.; Capitani, Joseph F.

2015-01-01

The title compound, C30H28O2, was obtained during recrystallization of (±)-1,2-diphenyl-1,2-propane­diol in 1-butanol, from an unexpected non-acid-catalyzed pinacol rearrangement followed by acetal formation of the newly formed aldehyde with the diol. The tri-substituted dioxolane ring has a twist conformation on the C—O bond opposite the methyl-substituted C atom. There is an intra­molecular C—H⋯π inter­action present involving one of the di­phenyl­ethyl rings and an H atom of the phenyl ring in position 4 of the dioxolane ring. In the crystal, mol­ecules are linked by weak C—H⋯O hydrogen bonds, forming chains along [001]. The chains are linked by a second C—H⋯π inter­action, forming sheets parallel to the bc plane. PMID:26594491

Isolation and characterization of a newly identified impurity in methamphetamine synthesized via reductive amination of 1-phenyl-2-propanone (P2P) made from phenylacetic acid/lead (II) acetate.

PubMed

Toske, Steven G; McConnell, Jennifer B; Brown, Jaclyn L; Tuten, Jennifer M; Miller, Erin E; Phillips, Monica Z; Vazquez, Etienne R; Lurie, Ira S; Hays, Patrick A; Guest, Elizabeth M

2017-03-01

A trace processing impurity found in certain methamphetamine exhibits was isolated and identified as trans-N-methyl-4-methyl-5-phenyl-4-penten-2-amine hydrochloride (1). It was determined that this impurity was produced via reductive amination of trans-4-methyl-5-phenyl-4-penten-2-one (4), which was one of a cluster of related ketones generated during the synthesis of 1-phenyl-2-propanone (P2P) from phenylacetic acid and lead (II) acetate. This two-step sequence resulted in methamphetamine containing elevated levels of 1. In contrast, methamphetamine produced from P2P made by other methods produced insignificant (ultra-trace or undetectable) amounts of 1. These results confirm that 1 is a synthetic marker compound for the phenylacetic acid and lead (II) acetate method. Analytical data for 1 and 4, and a postulated mechanism for the production of 4, are presented. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

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

PubMed

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

2005-01-01

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

Separator Membrane from Crosslinked Poly(Vinyl Alcohol) and Poly(Methyl Vinyl Ether-alt-Maleic Anhydride)

PubMed Central

Rohatgi, Charu Vashisth; Dutta, Naba K.; Choudhury, Namita Roy

2015-01-01

In this work, we report separator membranes from crosslinking of two polymers, such as poly vinyl alcohol (PVA) with an ionic polymer poly(methyl vinyl ether-alt-maleic anhydride) (PMVE-MA). Such interpolymer-networked systems were extensively used for biomedical and desalination applications but they were not examined for their potential use as membranes or separators for batteries. Therefore, the chemical interactions between these two polymers and the influence of such crosslinking on physicochemical properties of the membrane are systematically investigated through rheology and by critical gel point study. The hydrogen bonding and the chemical interaction between PMVE-MA and PVA resulted in highly cross-linked membranes. Effect of the molecular weight of PVA on the membrane properties was also examined. The developed membranes were extensively characterized by studying their physicochemical properties (water uptake, swelling ratio, and conductivity), thermal and electrochemical properties using differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), thermo-gravimetric analysis (TGA) and electrochemical impedance spectroscopy (EIS). The DSC study shows the presence of a single Tg in the membranes indicating compatibility of the two polymers in flexible and transparent films. The membranes show good stability and ion conductivity suitable for separator applications. PMID:28347019

Biodegradation of potential diesel oxygenate additives: dibutyl maleate (DBM), and tripropylene glycol methyl ether (TGME).

PubMed

Marchetti, Alfredo A; Knize, Mark G; Chiarappa-Zucca, Marina L; Pletcher, Ronald J; Layton, David W

2003-08-01

The addition of oxygen-bearing compounds to diesel fuel considerably reduces particulate emissions. TGME and DBM have been identified as possible diesel additives based on their physicochemical characteristics and performance in engine tests. Although these compounds will reduce particulate emissions, their potential environmental impacts are unknown. As a means of characterizing their persistence in environmental media such as soil and groundwater, we conducted a series of biodegradation tests of DBM and TGME. Benzene and methyl tertiary butyl ether (MTBE) were also tested as reference compounds. Primary degradation of DBM fully occurred within 3 days, while TGME presented a lag phase of approximately 8 days and was not completely degraded by day 28. Benzene primary degradation occurred completely by day 3 and MTBE did not degrade at all. The total mineralized fractions of DBM and TGME achieved constant values as a function of time of approximately 65% and approximately 40%, respectively. Transport predictions show that, released to the environment, DBM and TGME would concentrate mostly in soils and waters with minimal impact to air. From an environmental standpoint, these results combined with the transport predictions indicate that DBM is a better choice than TGME as a diesel additive.

(O-Methyl di-thio-carbonato-κS)tri-phenyl-tin(IV).

PubMed

Javed, Fatima; Ali, Saqib; Shah, Wajid; Tahir, M Nawaz; Ullah, Hameed

2013-06-01

In the title compound, [Sn(C6H5)3(C2H3OS2)], the Sn(IV) atom adopts a distorted SnC3S tetra-hedral coordination geometry. A short Sn⋯O contact [2.988 (4) Å] is also present. The phenyl rings are each disordered over two sets of sites with an occupancy ratio of 0.550 (8):0.450 (8). The crystal studied was found to be a racemic twin with a twin component ratio of 0.57 (18):0.43 (18).

Design, synthesis, and characterization of (1-(4-aryl)- 1H-1,2,3-triazol-4-yl)methyl, substituted phenyl-6-methyl-2-oxo-1,2,3,4-tetrahydropyrimidine-5-carboxylates against Mycobacterium tuberculosis

PubMed Central

Venugopala, Katharigatta N; Dharma Rao, G B; Bhandary, Subhrajyoti; Pillay, Melendhran; Chopra, Deepak; Aldhubiab, Bandar E; Attimarad, Mahesh; Alwassil, Osama Ibrahim; Harsha, Sree; Mlisana, Koleka

2016-01-01

The novel (1-(4-aryl)-1H-1,2,3-triazol-4-yl)methyl, substituted phenyl-6-methyl-2-oxo-1,2,3,4-tetrahydropyrimidine-5-carboxylate derivatives were synthesized by the click reaction of the dihydropyrimidinones, bearing a terminal alkynyl group, with various substituted aryl azides at room temperature using a catalytic amount of Cu(OAc)2 and sodium ascorbate in a 1:2 ratio of acetone and water as a solvent. The newly synthesized compounds were characterized by a number of spectroscopic techniques, such as infrared, liquid chromatography-mass spectrometry, 1H, and 13C nuclear magnetic resonance along with single crystal X-ray diffraction. The current procedure for the synthesis of 1,2,3-triazole hybrids with dihydropyrimidinones is appropriate for the synthesis of a library of analogs 7a-l and the method accessible here is operationally simple and has excellent yields. The title compounds 7a-l were evaluated for their in vitro antitubercular activity against H37RV and multidrug-resistant strains of Mycobacterium tuberculosis by resazurin microplate assay plate method and it was found that compound 7d was promising against H37RV and multidrug-resistant strains of M. tuberculosis at 10 and 15 μg/mL, respectively. PMID:27601885

Design, synthesis, and characterization of (1-(4-aryl)- 1H-1,2,3-triazol-4-yl)methyl, substituted phenyl-6-methyl-2-oxo-1,2,3,4-tetrahydropyrimidine-5-carboxylates against Mycobacterium tuberculosis.

PubMed

Venugopala, Katharigatta N; Dharma Rao, G B; Bhandary, Subhrajyoti; Pillay, Melendhran; Chopra, Deepak; Aldhubiab, Bandar E; Attimarad, Mahesh; Alwassil, Osama Ibrahim; Harsha, Sree; Mlisana, Koleka

2016-01-01

The novel (1-(4-aryl)-1H-1,2,3-triazol-4-yl)methyl, substituted phenyl-6-methyl-2-oxo-1,2,3,4-tetrahydropyrimidine-5-carboxylate derivatives were synthesized by the click reaction of the dihydropyrimidinones, bearing a terminal alkynyl group, with various substituted aryl azides at room temperature using a catalytic amount of Cu(OAc)2 and sodium ascorbate in a 1:2 ratio of acetone and water as a solvent. The newly synthesized compounds were characterized by a number of spectroscopic techniques, such as infrared, liquid chromatography-mass spectrometry, (1)H, and (13)C nuclear magnetic resonance along with single crystal X-ray diffraction. The current procedure for the synthesis of 1,2,3-triazole hybrids with dihydropyrimidinones is appropriate for the synthesis of a library of analogs 7a-l and the method accessible here is operationally simple and has excellent yields. The title compounds 7a-l were evaluated for their in vitro antitubercular activity against H37RV and multidrug-resistant strains of Mycobacterium tuberculosis by resazurin microplate assay plate method and it was found that compound 7d was promising against H37RV and multidrug-resistant strains of M. tuberculosis at 10 and 15 μg/mL, respectively.

Analysis of polybrominated diphenyl ethers and emerging halogenated and organophosphate flame retardants in human hair and nails.

PubMed

Liu, Liang-Ying; Salamova, Amina; He, Ka; Hites, Ronald A

2015-08-07

A method for the digestion, extraction, fractionation, and analysis of three classes of flame retardants, including 36 polybrominated diphenyl ethers (PBDEs), 9 halogenated alternative flame retardants (AFRs), and 12 organophosphate esters (OPEs) in human hair and nail samples was developed. The method employed HNO3/H2O2 digestion, liquid-liquid extraction with (4:1 vol) hexane:dichloromethane, fractionation on a 6g column of 2.5% water deactivated Florisil, and analysis by gas chromatographic mass spectrometry. The accuracy and precision of the method was validated using spiked samples of 6 replicates for both hair and nail samples. The method validation results showed good accuracy and precision for all PBDEs except BDE-209, all AFRs except hexabromobenzene (HBB), and all of the 12 OPEs, with average recovery efficiencies>90% and relative standard deviations (RSDs)<10%. The average recovery efficiencies for HBB were between 60% and 86%, with RSDs<10%. BDE-209 had recovery efficiencies of 64% (RSD, 13%) for hair and 71% (RSD, 10%) for nail. This method was applied to analyze 5 human hair and 5 fingernail samples from the general student population at Indiana University Bloomington campus. BDE-47 and BDE-99 were the predominant PBDEs detected in both hair and nail samples, with a concentration range of 11-620 and 4.6-780ng/g (dry weight) in hair and 7.3-43 and 2.1-11ng/g in nails, respectively. Di-(2-ethylhexyl)-tetrabromophthalate (TBPH) and 2-ethylhexyl-2,3,4,5-tetrabromobenzoate (TBB) were detected in all the samples, with concentrations of 20-240 and 11-350ng/g in hair and <17-80 and <9.2-71ng/g in nails, respectively. Among the 12 OPEs analyzed, tris(2-chloroethyl)phosphate (TCEP), tris(1-chloro-2-propyl)phosphate (TCIPP), tris(1,3-dichloro-2-propyl) phosphate (TDCIPP), and triphenyl phosphate (TPHP) were most often detected. The concentrations of these OPEs (summed together) were 1100-3900 and 380-18,000ng/g in hair and nails, respectively. These levels

Carbon Conversion Efficiency and Limits of Productive Bacterial Degradation of Methyl tert-Butyl Ether and Related Compounds▿

PubMed Central

Müller, Roland H.; Rohwerder, Thore; Harms, Hauke

2007-01-01

The utilization of the fuel oxygenate methyl tert-butyl ether (MTBE) and related compounds by microorganisms was investigated in a mainly theoretical study based on the YATP concept. Experiments were conducted to derive realistic maintenance coefficients and Ks values needed to calculate substrate fluxes available for biomass production. Aerobic substrate conversion and biomass synthesis were calculated for different putative pathways. The results suggest that MTBE is an effective heterotrophic substrate that can sustain growth yields of up to 0.87 g g−1, which contradicts previous calculation results (N. Fortin et al., Environ. Microbiol. 3:407-416, 2001). Sufficient energy equivalents were generated in several of the potential assimilatory routes to incorporate carbon into biomass without the necessity to dissimilate additional substrate, efficient energy transduction provided. However, when a growth-related kinetic model was included, the limits of productive degradation became obvious. Depending on the maintenance coefficient ms and its associated biomass decay term b, growth-associated carbon conversion became strongly dependent on substrate fluxes. Due to slow degradation kinetics, the calculations predicted relatively high threshold concentrations, Smin, below which growth would not further be supported. Smin strongly depended on the maximum growth rate μmax, and b and was directly correlated with the half maximum rate-associated substrate concentration Ks, meaning that any effect impacting this parameter would also change Smin. The primary metabolic step, catalyzing the cleavage of the ether bond in MTBE, is likely to control the substrate flux in various strains. In addition, deficits in oxygen as an external factor and in reduction equivalents as a cellular variable in this reaction should further increase Ks and Smin for MTBE. PMID:17220260

METHYL TERT-BUTYLETHER-WATER INTERACTION

EPA Science Inventory

Methyl tert-butyl ether (MTBE) is a well-known environmental contaminant owing to its high solubility in water. Since the early 1990s, MTBE has been added to gasoline to improve air quality in some metropolitan areas of the United States. Improved air quality was, however, achiev...

Chemical bonding and the equilibrium composition of Grignard reagents in ethereal solutions.

PubMed

Henriques, André M; Barbosa, André G H

2011-11-10

A thorough analysis of the electronic structure and thermodynamic aspects of Grignard reagents and its associated equilibrium composition in ethereal solutions is performed. Considering methylmagnesium halides containing fluorine, chlorine, and bromine, we studied the neutral, charged, and radical species associated with their chemical equilibrium in solution. The ethereal solvents considered, tetrahydrofuran (THF) and ethyl ether (Et(2)O), were modeled using the polarizable continuum model (PCM) and also by explicit coordination to the Mg atoms in a cluster. The chemical bonding of the species that constitute the Grignard reagent is analyzed in detail with generalized valence bond (GVB) wave functions. Equilibrium constants were calculated with the DFT/M06 functional and GVB wave functions, yielding similar results. According to our calculations and existing kinetic and electrochemical evidence, the species R(•), R(-), (•)MgX, and RMgX(2)(-) must be present in low concentration in the equilibrium. We conclude that depending on the halogen, a different route must be followed to produce the relevant equilibrium species in each case. Chloride and bromide must preferably follow a "radical-based" pathway, and fluoride must follow a "carbanionic-based" pathway. These different mechanisms are contrasted against the available experimental results and are proven to be consistent with the existing thermodynamic data on the Grignard reagent equilibria.

Dissociative Photoionization of 1-Halogenated Silacyclohexanes: Silicon Traps the Halogen.

PubMed

Bodi, Andras; Sigurdardottir, Katrin Lilja; Kvaran, Ágúst; Bjornsson, Ragnar; Arnason, Ingvar

2016-11-23

The threshold photoelectron spectra and threshold photoionization mass spectra of 1-halogenated-1-silacyclohexanes, for the halogens X = F, Cl, Br, and I, have been obtained using synchrotron vacuum ultraviolet radiation and photoelectron photoion coincidence spectroscopy. As confirmed by a similar ionization onset and density functional theory molecular orbitals, the ionization to the ground state is dominated by electron removal from the silacyclohexane ring for X = F, Cl, and Br, and from the halogen lone pair for X = I. The breakdown diagrams show that the dissociative photoionization mechanism is also different for X = I. Whereas the parent ions decay by ethylene loss for X = F to Br in the low-energy regime, the iodine atom is lost for X = I. The first step is followed by a sequential ethylene loss at higher internal energies in each of the compounds. It is argued that the tendency of silicon to lower bond angles stabilizes the complex cation in which C 2 H 4 is η 2 -coordinated to it, and which precedes ethylene loss. Together with the relatively strong silicon-halogen bonds and the increased inductive effect of the silacyclohexane ring in stabilizing the cation, this explains the main differences observed in the fragmentation of the halogenated silacyclohexane and halogenated cyclohexane ions. The breakdown diagrams have been modeled taking into account slow dissociations at threshold and the resulting kinetic shift. The 0 K appearance energies have been obtained to within 0.08 eV for the ethylene loss for X = F to Br (10.56, 10.51, and 10.51 eV, respectively), the iodine atom loss for X = I (10.11 eV), the sequential ethylene loss for X = F to I (12.29, 12.01, 11.94, and 11.86 eV, respectively), and the minor channels of H loss for X = F (10.56 eV) and propylene loss in X = Cl (also at 10.56 eV). The appearance energies for the major channels likely correspond to the dissociative photoionization reaction energy.

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

NASA Astrophysics Data System (ADS)

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

2018-01-01

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

3-methyl-2-phenyl-1-substituted-indole derivatives as indomethacin analogs: design, synthesis and biological evaluation as potential anti-inflammatory and analgesic agents.

PubMed

Abdellatif, Khaled R A; Lamie, Phoebe F; Omar, Hany A

2016-01-01

In a new group of 3-methyl-2-phenyl-1-substituted-indole derivatives (10a-f), the indomethacin analogs were prepared via the Fisher indole synthesis reaction of propiophenone with appropriately substituted phenylhydrazine hydrochloride. This is followed by the insertion of the appropriate benzyl or benzoyl fragment. All the synthesized compounds were evaluated for their anti-inflammatory (in vitro and in vivo) and analgesic activities. The methanesulphonyl derivatives 10d, e and f showed the highest anti-inflammatory (in vitro and in vivo) and analgesic activities. In addition, molecular docking studies were performed on compounds 10a-f and the results were in agreement with that obtained from the in vitro COX inhibition assays. The significant anti-inflammatory and analgesic activities exhibited by 10d and 10e warrant continued preclinical development as potential anti-inflammatory and analgesic agents.

Boiling points of halogenated ethanes: an explanatory model implicating weak intermolecular hydrogen-halogen bonding.

PubMed

Beauchamp, Guy

2008-10-23

This study explores via structural clues the influence of weak intermolecular hydrogen-halogen bonds on the boiling point of halogenated ethanes. The plot of boiling points of 86 halogenated ethanes versus the molar refraction (linked to polarizability) reveals a series of straight lines, each corresponding to one of nine possible arrangements of hydrogen and halogen atoms on the two-carbon skeleton. A multiple linear regression model of the boiling points could be designed based on molar refraction and subgroup structure as independent variables (R(2) = 0.995, standard error of boiling point 4.2 degrees C). The model is discussed in view of the fact that molar refraction can account for approximately 83.0% of the observed variation in boiling point, while 16.5% could be ascribed to weak C-X...H-C intermolecular interactions. The difference in the observed boiling point of molecules having similar molar refraction values but differing in hydrogen-halogen intermolecular bonds can reach as much as 90 degrees C.

Halogen Chemistry in the CMAQ Model

EPA Science Inventory

Halogens (iodine and bromine) emitted from oceans alter atmospheric chemistry and influence atmospheric ozone mixing ratio. We previously incorporated a representation of detailed halogen chemistry and emissions of organic and inorganic halogen species into the hemispheric Commun...

Concentration determination of methyl magnesium chloride and other Grignard reagents by potentiometric titration with in-line characterization of reaction species by FTIR spectroscopy.

PubMed

Chen, Yadan; Wang, Tao; Helmy, Roy; Zhou, George X; LoBrutto, Rosario

2002-07-01

A potentiometric titration method for methyl magnesium chloride and other Grignard reagents based on the reaction with 2-butanol in THF has been developed and validated. The method employs a commercially available platinum electrode, using an electrolyte compatible with non-aqueous solvents. Well-defined titration curves were obtained, along with excellent method precision. The endpoint was precisely determined based on the first derivative of the titration curve. Different solvents such as THF, diethyl ether and methylene chloride provided similar results with regard to sharpness of the endpoint and method precision. The method was applied to a wide array of Grignard reagents including methyl magnesium bromide, ethyl magnesium chloride, propyl magnesium chloride, vinyl magnesium chloride, phenyl magnesium chloride, and benzyl magnesium chloride with similar precision and accuracy. Application of in-line FTIR was demonstrated for in situ monitoring of the titration reaction, allowing characterization of the reaction species. An authentic spectrum of the MeMgCl-THF complex was obtained using spectral subtraction and the vibrational absorbance bands were identified. FTIR also provided an alternative for detecting the titration endpoint, and the titration results so obtained, provided a cross-validation of the accuracy of the potentiometric titration.

Arbuscular mycorrhizal fungi in a wetland constructed for benzene-, methyl tert-butyl ether- and ammonia-contaminated groundwater bioremediation

PubMed Central

Fester, Thomas

2013-01-01

Arbuscular mycorrhizal fungi (AMF), which are present in most natural environments, have demonstrated capacity to promote biodegradation of organic pollutants in the greenhouse. However, it is not certain whether AMF can spontaneously establish in phytoremediation systems constructed to decontaminate groundwater, because of the unusual conditions during the construction and operation of such systems. To assess this possibility, root samples from a wetland constructed for the phytoremediation of groundwater contaminated with benzene, methyl tert-butyl ether and ammonia were analysed. Substantial AMF colonization was observed in plant roots sampled close to the inlet of a basin filled with fine gravel and planted with Phragmites australis. In addition, analysis of a fragment of the nuclear large ribosomal subunit, amplified by nested PCR, revealed the presence of AMF molecular operational taxonomic units closely related to Funneliformis mosseae and Rhizophagus irregularis in the samples. These findings demonstrate the capacity of generalist AMF strains to establish spontaneously, rapidly and extensively in groundwater bioremediation technical installations. PMID:22846140

A new cytotoxic sterol methoxymethyl ether from a deep water marine sponge Scleritoderma sp. cf. paccardi.

PubMed

Gunasekera, S P; Kelly-Borges, M; Longley, R E

1996-02-01

24(R)-Methyl-5 alpha-cholest-7-enyl 3 beta-methoxymethyl ether (1), a new sterol ether, has been isolated from a deep-water marine sponge Scleritoderma sp. cf. paccardi. Compound 1 exhibited in vitro cytotoxicity against the cultured murine P-388 tumor cell line with an IC50 of 2.3 micrograms/mL. The isolation and structure elucidation of 1 by NMR spectroscopy is described.

Separation and determination of methyl tert-butyl ether and its degradation products by a laboratory-constructed micro-cryogenic chromatographic oven.

PubMed

Liu, Jiemin; Jiang, Guibin; Zhou, Qunfang; Liu, Jingfu; Wen, Meijuan

2003-10-01

A laboratory-made micro-cryogenic chromatographic oven was mainly improved in size, which was controlled at 6 x 6 x 2.5 cm. A thermoelectric system was used to cool the capillary column instead of the traditional liquid cryogen. A cold block connected to the cryogenic module was directly solidified at room temperature with thermally conductive adhesive so that the uniformity of transferring heat was greatly improved, and the size of the system was reduced. Moreover, this system was inexpensive and convenient for both operation and control. The newly developed device coupled with headspace solid-phase microextraction (SPME) was successfully applied to the determination of methyl tert-butyl ether (MTBE) and its degradation products. During the analysis procedure, a 65 microm polydimethylsiloxane/divinylbenzene (PDMS/DVB) fiber was used to extract MTBE and its degradation products. The extraction was controlled at 50 degrees C for 30 min and the NaCl content in the sample was maintained at 35%. The limits of detection (LODs) ranged from 0.006 microg mL(-1) (for MTBE) to 0.206 microg mL(-1) (for methyl acetate) and the relative standard deviations (RSD%) were below 4%. The spiked recoveries for the developed method were evaluated using various water samples as a matrix.

Ether bond effects in quaternary ammonium and phosphonium ionic liquid-propanol solutions

NASA Astrophysics Data System (ADS)

Kishimura, Hiroaki; Kohki, Erica; Nakada, Ayumu; Tamatani, Kentaro; Abe, Hiroshi

2018-03-01

The liquid-liquid equilibria (LLE) of quaternary ammonium and phosphonium ionic liquid (IL)-propanol solutions were examined. The ILs contained cations with or without ether bonds; the anion in all the ILs was bis(trifluoromethanesulfonyl)imide (TFSI-). The cations without ether groups are tributylmethyl ammonium (N4441+), triethylpentyl phosphonium (P2225+), triethyloctyl phosphonium (P2228+), and tributylmethyl phosphonium (P4441+). The cations containing ether groups are N,N-diethyl-N-methyl-N-(2-methoxyethyl) ammonium, (N122(2O1)+), triethyl(methoxymethyl) phosphonium (P222(1O1)+), and triethyl(2-methoxyethyl) phosphonium, (P222(2O1)+). Propanol isomer effect was observed to affect the LLEs, reflecting the geometrical factors and hydrophobicities of 1-propanol and 2-propanol. According to Raman spectroscopy, the TFSI- anion conformers in the mixtures were altered in the presence of ether bonds in the cations. The universal quasichemical (UNIQUAC) interaction parameters are consistent with significant factors affecting IL-propanol solutions, such as the type of cation (ammonium or phosphonium), ether bonds, TFSI- conformers, and propanol isomer effects.

Halogen bonding from a hard and soft acids and bases perspective: investigation by using density functional theory reactivity indices.

PubMed

Pinter, Balazs; Nagels, Nick; Herrebout, Wouter A; De Proft, Frank

2013-01-07

Halogen bonds between the trifluoromethyl halides CF(3)Cl, CF(3)Br and CF(3)I, and dimethyl ether, dimethyl sulfide, trimethylamine and trimethyl phosphine were investigated using Pearson's hard and soft acids and bases (HSAB) concept with conceptual DFT reactivity indices, the Ziegler-Rauk-type energy-decomposition analysis, the natural orbital for chemical valence (NOCV) framework and the non-covalent interaction (NCI) index. It is found that the relative importance of electrostatic and orbital (charge transfer) interactions varies as a function of both the donor and acceptor molecules. Hard and soft interactions were distinguished and characterised by atomic charges, electrophilicity and local softness indices. Dual-descriptor plots indicate an orbital σ hole on the halogen similar to the electrostatic σ hole manifested in the molecular electrostatic potential. The predicted high halogen-bond-acceptor affinity of N-heterocyclic carbenes was evidenced in the highest complexation energy for the hitherto unknown CF(3) I·NHC complex. The dominant NOCV orbital represents an electron-density deformation according to a n→σ*-type interaction. The characteristic signal found in the reduced density gradient versus electron-density diagram corresponds to the non-covalent interaction between contact atoms in the NCI plots, which is the manifestation of halogen bonding within the NCI theory. The unexpected C-X bond strengthening observed in several cases was rationalised within the molecular orbital framework. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Poly(arylene ether)s containing pendent ethynyl groups

NASA Technical Reports Server (NTRS)

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

1996-01-01

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.

Poly(arylene ether)s containing pendent ethynyl groups

NASA Technical Reports Server (NTRS)

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

1994-01-01

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 C to provide crosslinked poly(arylene ether)s with good solvent resistance, high strength and modulus.

Mode of Action Studies on Nitrodiphenyl Ether Herbicides

PubMed Central

Bowyer, John R.; Smith, Beverly J.; Camilleri, Patrick; Lee, Susan A.

1987-01-01

5-[2-Chloro-4-(trifluoromethyl)phenoxy]-2-nitroacetophenone oxime-o-(acetic acid, methyl ester) (DPEI), is a potent nitrodiphenyl ether herbicide which causes rapid leaf wilting, membrane lipid peroxidation, and chlorophyll destruction in a process which is both light- and O2-dependent. These effects resemble those of other nitrodiphenyl ether herbicides. Unlike paraquat, the herbicidal effects of DPEI are only slightly reduced by pretreatment with the photosynthetic electron transport inhibitor 3-(3,4-dichlorophenyl)-1,1-dimethylurea. DPEI is a weak inhibitor of photosynthetic electron transport (I50 15 micromolar for water to paraquat) in vitro, with at least one site of action at the cytochrome b6f complex. Ultrastructural studies and measurements of ethane formation resulting from lipid peroxidation indicate that mutants of barley lacking photosystem I (PSI) (viridis-zb63) or photosystem II (viridis-zd69) are resistant to paraquat but susceptible to DPEI. The results indicate that electron transfer through both photosystems is not essential for the toxic effects of nitrodiphenyl ether herbicides. Furthermore, the results show that neither cyclic electron transport around PSI, nor the diversion of electrons from PSI to O2 when NADPH consumption is blocked are essential for the phytotoxicity of nitrodiphenyl ether herbicides. Images Fig. 2 Fig. 3 Fig. 4 PMID:16665297

Comparative transcriptome analysis of Methylibium petroleiphilum PM1 exposed to the fuel oxygenates methyl tert-butyl ether and ethanol.

PubMed

Hristova, Krassimira R; Schmidt, Radomir; Chakicherla, Anu Y; Legler, Tina C; Wu, Janice; Chain, Patrick S; Scow, Kate M; Kane, Staci R

2007-11-01

High-density whole-genome cDNA microarrays were used to investigate substrate-dependent gene expression of Methylibium petroleiphilum PM1, one of the best-characterized aerobic methyl tert-butyl ether (MTBE)-degrading bacteria. Differential gene expression profiling was conducted with PM1 grown on MTBE and ethanol as sole carbon sources. Based on microarray high scores and protein similarity analysis, an MTBE regulon located on the megaplasmid was identified for further investigation. Putative functions for enzymes encoded in this regulon are described with relevance to the predicted MTBE degradation pathway. A new unique dioxygenase enzyme system that carries out the hydroxylation of tert-butyl alcohol to 2-methyl-2-hydroxy-1-propanol in M. petroleiphilum PM1 was discovered. Hypotheses regarding the acquisition and evolution of MTBE genes as well as the involvement of IS elements in these complex processes were formulated. The pathways for toluene, phenol, and alkane oxidation via toluene monooxygenase, phenol hydroxylase, and propane monooxygenase, respectively, were upregulated in MTBE-grown cells compared to ethanol-grown cells. Four out of nine putative cyclohexanone monooxygenases were also upregulated in MTBE-grown cells. The expression data allowed prediction of several hitherto-unknown enzymes of the upper MTBE degradation pathway in M. petroleiphilum PM1 and aided our understanding of the regulation of metabolic processes that may occur in response to pollutant mixtures and perturbations in the environment.

Evidence for Interfacial Halogen Bonding.

PubMed

Swords, Wesley B; Simon, Sarah J C; Parlane, Fraser G L; Dean, Rebecca K; Kellett, Cameron W; Hu, Ke; Meyer, Gerald J; Berlinguette, Curtis P

2016-05-10

A homologous series of donor-π-acceptor dyes was synthesized, differing only in the identity of the halogen substituents about the triphenylamine (TPA; donor) portion of each molecule. Each Dye-X (X=F, Cl, Br, and I) was immobilized on a TiO2 surface to investigate how the halogen substituents affect the reaction between the light-induced charge-separated state, TiO2 (e(-) )/Dye-X(+) , with iodide in solution. Transient absorption spectroscopy showed progressively faster reactivity towards nucleophilic iodide with more polarizable halogen substituents: Dye-F < Dye-Cl < Dye-Br < Dye-I. Given that all other structural and electronic properties for the series are held at parity, with the exception of an increasingly larger electropositive σ-hole on the heavier halogens, the differences in dye regeneration kinetics for Dye-Cl, Dye-Br, and Dye-I are ascribed to the extent of halogen bonding with the nucleophilic solution species. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Iron-catalyzed halogenation of alkanes: modeling of nonheme halogenases by experiment and DFT calculations.

PubMed

Comba, Peter; Wunderlich, Steffen

2010-06-25

When the dichloroiron(II) complex of the tetradentate bispidine ligand L=3,7-dimethyl-9-oxo-2,4-bis(2-pyridyl)-3,7-diazabicyclo[3.3.1]nonane-1,5-dicarboxylate methyl ester is oxidized with H(2)O(2), tBuOOH, or iodosylbenzene, the high-valent Fe=O complex efficiently oxidizes and halogenates cyclohexane. Kinetic D isotope effects and the preference for the abstraction of tertiary over secondary carbon-bound hydrogen atoms (quantified in the halogenation of adamantane) indicate that C-H activation is the rate-determining step. The efficiencies (yields in stoichiometric and turnover numbers in catalytic reactions), product ratios (alcohol vs. bromo- vs. chloroalkane), and kinetic isotope effects depend on the oxidant. These results suggest different pathways with different oxidants, and these may include iron(IV)- and iron(V)-oxo complexes as well as oxygen-based radicals.

Tropospheric Halogen Chemistry

NASA Astrophysics Data System (ADS)

von Glasow, R.; Crutzen, P. J.

2003-12-01

Halogens are very reactive chemicals that are known to play an important role in anthropogenic stratospheric ozone depletion chemistry, first recognized by Molina and Rowland (1974). However, they also affect the chemistry of the troposphere. They are of special interest because they are involved in many reaction cycles that can affect the oxidation power of the atmosphere indirectly by influencing the main oxidants O3 and its photolysis product OH and directly, e.g., by reactions of the Cl radical with hydrocarbons (e.g., CH4).Already by the middle of the nineteenth century, Marchand (1852) reported the presence of bromine and iodine in rain and other natural waters. He also mentions the benefits of iodine in drinking water through the prevention of goitres and cretinism. In a prophetic monograph "Air and Rain: The Beginnings of a Chemical Climatology," Smith (1872) describes measurements of chloride in rain water, which he states to originate partly from the oceans by a process that he compares with the bursting of "soap bubbles" which produces "small vehicles" that transfer small spray droplets of seawater to the air. From deviations of the sulfate-to-chloride ratio in coastal rain compared to seawater, Smith concluded that chemical processes occur once the particles are airborne.For almost a century thereafter, however, atmospheric halogens received little attention. One exception was the work by Cauer (1939), who reported that iodine pollution has been significant in Western and Central Europe due to the inefficient burning of seaweed, causing mean gas phase atmospheric concentrations as high as or greater than 0.5 μg m-3. In his classical textbook Air Chemistry and Radioactivity, Junge (1963) devoted less than three pages to halogen gas phase chemistry, discussing chlorine and iodine. As reviewed by Eriksson (1959a, b), the main atmospheric source of halogens is sea salt, derived from the bursting of bubbles of air which are produced by ocean waves and other

On the inapplicability of electron-hopping models for the organic semiconductor Phenyl-C61-butyric Acid Methyl Ester (PCBM)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gajdos, Fruzsina; Oberhofer, Harald; Dupuis, Michel

2013-03-21

Phenyl-C61-butyric Acid Methyl Ester (PCBM) is one of the most popular semiconductors in organic photovoltaic cells, but the electron transport mechanism in the microcrystalline domains of this material as well as its preferred packing structure remains unclear. Here we use density functional theory to calculate electronic coupling matrix elements, reorganization energies and activation energies for available experimental and model crystal structures. We find that the picture of an excess electron hopping from one fullerene to another does not apply for any of the crystalline phases, rendering traditional rate equations inappropriate. We also find that the cohesive energy increases in themore » order body-centred-cubic < hexagonal < simple cubic < monoclinic < triclinic, independently on the type of dispersion correction used. Our results indicate that the electron-ion dynamics needs to be solved explicitly in order to obtain a realistic description of charge transfer in this material. M.D. was supported by the U.S. Department of Energy (DOE), Office of Basic Energy Sciences (BES), Division of Chemical Sciences, Geosciences and Biosciences. PNNL is a multiprogram national laboratory operated for DOE by Battelle.« less

Halogenated solvent remediation

DOEpatents

Sorenson, Jr., Kent S.

2008-11-11

Methods for enhancing bioremediation of ground water contaminated with nonaqueous halogenated solvents are disclosed. An illustrative method includes adding an electron donor for microbe-mediated anaerobic reductive dehalogenation of the halogenated solvents, which electron donor enhances mass transfer of the halogenated solvents from residual source areas into the aqueous phase of the ground water. Illustrative electron donors include C.sub.2-C.sub.4 carboxylic acids and hydroxy acids, salts thereof, esters of C.sub.2-C.sub.4 carboxylic acids and hydroxy acids, and mixtures thereof, of which lactic acid, salts of lactic acid--such as sodium lactate, lactate esters, and mixtures thereof are particularly illustrative. The microbes are either indigenous to the ground water, or such microbes can be added to the ground water in addition to the electron donor.

Seasonal and daily variations in concentrations of methyl-tertiary-butyl ether (MTBE) at Cranberry Lake, New Jersey

USGS Publications Warehouse

Toran, L.; Lipka, C.; Baehr, A.; Reilly, T.; Baker, R.

2003-01-01

Methyl-tertiary-butyl ether (MTBE), an additive used to oxygenate gasoline, has been detected in lakes in northwestern New Jersey. This occurrence has been attributed to the use of gasoline-powered watercraft. This paper documents and explains both seasonal and daily variations in MTBE concentrations at Cranberry Lake. During a recent boating season (late April to September 1999), concentrations of MTBE typically exceeded 20??g/L. MTBE concentrations varied daily from 12 to 24??g/L over a 2-week period that included the Labor Day holiday. Concentrations were highest on weekends when there is more boat traffic, which had an immediate effect on MTBE mass throughout the lake. MTBE concentrations decreased to about 2??g/L shortly after the end of the summer recreational season. The loss of MTBE can be accounted for by volatilization, with a half-life on the order of 10 days. The volatilization rate was modeled with the daily decrease in MTBE then the modeled rate was validated using the data from the seasonal decline. ?? 2003 Elsevier Science Ltd. All rights reserved.

Dual-Responsive pH and Temperature Sensitive Nanoparticles Based on Methacrylic Acid and Di(ethylene glycol) Methyl Ether Methacrylate for the Triggered Release of Drugs.

PubMed

Khine, Yee Yee; Jiang, Yanyan; Dag, Aydan; Lu, Hongxu; Stenzel, Martina H

2015-08-01

A series of thermo-and pH-responsive poly(methyl methacrylate)-block-poly[methacrylic acid-co-di(ethylene glycol) methyl ether methacrylate] PMMA-b-P[MAA-co-DEGMA] block copolymers were synthesized by RAFT polymerization and self-assembled into micelles. The molar ratio of MAA was altered from 0-12% in order to modulate the lower critical solution temperature (LCST) of PDEGMA. The release of the drug albendazole from the micelle was strongly dependent on the temperature and the LCST value of the polymer. Systems below the LCST released the drug slowly while increasing the temperature above the LCST or decreasing the pH value to 5 resulted in the burst-like release of the drug. ABZ delivered in this pH-responsive drug carrier had a higher toxicity than the free drug or the drug delivered in a non-responsive drug carrier. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Halogenated boron-dipyrromethenes: synthesis, properties and applications.

PubMed

Lakshmi, Vellanki; Rao, Malakalapalli Rajeswara; Ravikanth, Mangalampalli

2015-03-07

Boron-dipyrromethene dyes (BODIPYs) containing halogens at pyrrole carbons are very useful synthons for the synthesis of a variety of BOIDPYs for a wide range of applications. Among the functional groups, halogens are the functional groups which can be regiospecifically introduced at any desired pyrrole carbon of the BODIPY framework by adopting appropriate synthetic strategies. The halogenated BODIPYs can undergo facile nucleophilic substitution reactions to prepare several interesting BODIPY based compounds. This review describes the synthesis, properties and potential applications of halogenated BODIPYs containing one to six halogens at the pyrrole carbons of the BODIPY core as well as properties and applications of some of the substituted BODIPYs derived from halogenated BODIPYs.

Binding specificity of the juvenile hormone carrier protein from the hemolymph of the tobacco hornworm Manduca sexta Johannson (Lepidoptera: Sphingidae).

PubMed

Peterson, R C; Reich, M F; Dunn, P E; Law, J H; Katzenellnbogen, J A

1977-05-17

A series of analogues of insect juvenile hormone (four geometric isomers of methyl epoxyfarnesenate, several para-substituted epoxygeranyl phenyl ethers, and epoxyfarnesol and its acetate and haloacetate derivatives) was prepared to investigate the binding specificity of the hemolymph juvenile hormone binding protein from the tobacco hornworm Manduct sexta. The relative binding affinities were determined by a competition assay against radiolabeled methyl (E,E)-3,11-dimethyl-7-ethyl-cis-10,11-epoxytrideca-2,6-dienoate (JH I). The ratio of dissociation constants was estimated by plotting competitor data according to a linear transformation of the dissociation equations describing competition of two ligands for a binding protein. The importance of the geometry of the sesquiterpene hydrocarbon chain is indicated by the fact that the binding affinity is decreased as Z (cis) double bonds are substituted for E (trans) double bonds in the methyl epoxyfarnesenate series; the unepoxidized analogues do not bind. A carboxylic ester function is important although its orientation can be reversed, as indicated by the good binding of epoxyfarnesyl acetate. In the monoterpene series, methyl epoxygeranoate shows no affinity for the binding protein, but substitution of a phenyl or p-carbomethoxyphenyl ether for the ester function imparts a low, but significant affinity. These data taken together with earlier results indicate that the binding site for juvenile hormone in the hemolymph binding protein is characterized by a sterically defined hydrophobic region with polar sites that recognize the epoxide and the ester functions.

Aerosol-halogen interaction: Change of physico-chemical properties of SOA by naturally released halogen species

NASA Astrophysics Data System (ADS)

Ofner, J.; Balzer, N.; Buxmann, J.; Grothe, H.; Krüger, H.; Platt, U.; Schmitt-Kopplin, P.; Zetzsch, C.

2011-12-01

Reactive halogen species are released by various sources like photo-activated sea-salt aerosol or salt pans and salt lakes. These heterogeneous release mechanisms have been overlooked so far, although their potential of interaction with organic aerosols like Secondary Organic Aerosol (SOA), Biomass Burning Organic Aerosol (BBOA) or Atmospheric Humic LIke Substances (HULIS) is completely unknown. Such reactions can constitute sources of gaseous organo-halogen compounds or halogenated organic particles in the atmospheric boundary layer. To study the interaction of organic aerosols with reactive halogen species (RHS), SOA was produced from α-pinene, catechol and guaiacol using an aerosol smog-chamber. The model SOAs were characterized in detail using a variety of physico-chemical methods (Ofner et al., 2011). Those aerosols were exposed to molecular halogens in the presence of UV/VIS irradiation and to halogens, released from simulated natural halogen sources like salt pans, in order to study the complex aerosol-halogen interaction. The heterogeneous reaction of RHS with those model aerosols leads to different gaseous species like CO2, CO and small reactive/toxic molecules like phosgene (COCl2). Hydrogen containing groups on the aerosol particles are destroyed to form HCl or HBr, and a significant formation of C-Br bonds could be verified in the particle phase. Carbonyl containing functional groups of the aerosol are strongly affected by the halogenation process. While changes of functional groups and gaseous species were visible using FTIR spectroscopy, optical properties were studied using Diffuse Reflectance UV/VIS spectroscopy. Overall, the optical properties of the processed organic aerosols are significantly changed. While chlorine causes a "bleaching" of the aerosol particles, bromine shifts the maximum of UV/VIS absorption to the red end of the UV/VIS spectrum. Further physico-chemical changes were recognized according to the aerosol size-distributions or the

Halogen bond: a long overlooked interaction.

PubMed

Cavallo, Gabriella; Metrangolo, Pierangelo; Pilati, Tullio; Resnati, Giuseppe; Terraneo, Giancarlo

2015-01-01

Because of their high electronegativity, halogen atoms are typically considered, in most of their derivatives, as sites of high electron density and it is commonly accepted that they can form attractive interactions by functioning as the electron donor site (nucleophilic site). This is the case when they work as hydrogen bond acceptor sites. However, the electron density in covalently bound halogens is anisotropically distributed. There is a region of higher electron density, accounting for the ability of halogens to function as electron donor sites in attractive interactions, and a region of lower electron density where the electrostatic potential is frequently positive (mainly in the heavier halogens). This latter region is responsible for the ability of halogen atoms to function as the electron-acceptor site (electrophilic site) in attractive interactions formed with a variety of lone pair-possessing atoms, anions, and π-systems. This ability is quite general and is shown by a wide diversity of halogenated compounds (e.g., organohalogen derivatives and dihalogens). According to the definition proposed by the International Union of Pure and Applied Chemistry, any attractive interactions wherein the halogen atom is the electrophile is named halogen bond (XB). In this chapter, it is discussed how the practice and the concept of XB developed and a brief history of the interaction is presented. Papers (either from the primary or secondary literature) which have reported major experimental findings in the field or which have given important theoretical contributions for the development of the concept are recollected in order to trace how a unifying and comprehensive categorization emerged encompassing all interactions wherein halogen atoms function as the electrophilic site.

Crystal structure, vibrational, spectral investigation, quantum chemical DFT calculations and thermal behavior of Diethyl [hydroxy (phenyl) methyl] phosphonate

NASA Astrophysics Data System (ADS)

Ouksel, Louiza; Chafaa, Salah; Bourzami, Riadh; Hamdouni, Noudjoud; Sebais, Miloud; Chafai, Nadjib

2017-09-01

Single Diethyl [hydroxy (phenyl) methyl] phosphonate (DHPMP) crystal with chemical formula C11H17O4P, was synthesized via the base-catalyzed Pudovik reaction and Lewis acid as catalyst. The results of SXRD analyzes indicate that this compound crystallizes into a mono-clinic system with space group P21/n symmetry and Z = 4. The crystal structure parameters are a = 9.293 Å, b = 8.103 Å, c = 17.542 Å, β = 95.329° and V = 1315.2 Å3, the structure displays one inter-molecular O-H⋯O hydrogen bonding. The UV-Visible absorption spectrum shows that the crystal exhibits a good optical transmission in the visible domain, and strong absorption in middle ultraviolet one. The vibrational frequencies of various functional groups present in DHPMP crystal have been deduced from FT-IR and FT-Raman spectra and then compared with theoretical values performed with DFT (B3LYP) method using 6-31G (p, d) basis sets. Chemical and thermodynamic parameters such as: ionization potential (I), electron affinity (A), hardness (σ), softness (η), electronegativity (χ) and electrophilicity index (ω), are also calculated using the same theoretical method. The thermal decomposition behavior of DHPMP, studied by using thermogravimetric analysis (TDG), shows a thermal stability until to 125 °C.

Loss of collapsin response mediator protein 4 suppresses dopaminergic neuron death in an 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced mouse model of Parkinson's disease.

PubMed

Tonouchi, Aine; Nagai, Jun; Togashi, Kentaro; Goshima, Yoshio; Ohshima, Toshio

2016-06-01

Parkinson's disease (PD) is a progressive neurodegenerative disorder that is characterized by the selective loss of dopaminergic neurons in the substantia nigra pars compacta (SNc). Several lines of evidence suggest that neurodegeneration in PD is accelerated by a vicious cycle in which apoptosis in dopaminergic neurons triggers the activation of microglia and harmful inflammatory processes that further amplify neuronal death. Recently, we demonstrated that the deletion of collapsin response mediator protein 4 (CRMP4) suppresses inflammatory responses and cell death in a mouse model of spinal cord injury, leading to improved functional recovery. We thus hypothesized that Crmp4-/- mice may have limited inflammatory responses and a decrease in the loss of SNc dopaminergic neurons in an 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD mouse model. We observed CRMP4 expression in neurons, astrocytes, and microglia/macrophages following the injection of 25 mg/kg MPTP. We compared the number of dopaminergic neurons and the inflammatory response in SNc between Crmp4+/+ and Crmp4-/- mice after MPTP injection. Limited loss of SNc dopaminergic neurons and decreased activations of microglia and astrocytes were observed in Crmp4-/- mice. These results suggest that CRMP4 is a novel therapeutic target in the treatment of PD patients. We demonstrated that genetic CRMP4 deletion delays a vicious cycle of inflammation and neurodegeneration in a Parkinson's disease mouse model. MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) injection to wild-type mice induces collapsin response mediator protein 4 (CRMP4) up-regulation in neurons, astrocytes, and microglia. CRMP4-deficient mice show reduced inflammation and suppressed dopaminergic neuronal death after MPTP injection. These findings suggest that CRMP4 deletion may be a new therapeutic strategy against Parkinson's diseases. © 2016 International Society for Neurochemistry.

Synthesis and characterisation of new Schiff base monomers containing N-(alkyl and phenyl) pyrrole moieties

NASA Astrophysics Data System (ADS)

Amer, Ahcene Ait; Ilikti, Hocine; Maschke, Ulrich

2017-11-01

This article deals with the synthesis and characterisation of seven new functional Schiff base monomers, such as: M1: 1-(3-Pyrrole-1-yl-propylimino-methyl)-naphtalen-2-ol; M2: 2-(3-Pyrrole-1-yl-phenylimino-methyl)-phenol; M3: 1-(3-Pyrrole-1-yl-phenylimino-methyl)-naphtalen-2-ol; M4: N-(pyridin-2-yl-methylene)-2-(pyrrol-1-yl)-benzenamine; M5: N-(pyridin-2-yl-methylene)-3-(pyrrol-1-yl)-propan-1-amine; M6: 2-(3-pyrrol-1-yl-propylimino-methyl)-quinolin-8-ol; M7: 2-(3-pyrrol-1-yl-phenylimino-methyl)-quinolin-8-ol. Two series of compounds emerged from this study, N-propyl pyrrole derivatives (M1, M5, M6) and N-phenyl pyrrole compounds (M2, M3, M4, M7). All monomers were elaborated by condensation reactions between appropriate amines and aldehydes, and their molecular structures were confirmed by spectroscopic analysis methods like FT-IR, 1H NMR, 13C NMR, and GC-MS.

Three-Dimensional Photochemical Machining with Lasers

DTIC Science & Technology

1983-11-30

559.91 (1.00) 4-Hydroxybenzophenone 27.78 79.42 359.97 (1.00) 0 19.42 55.52 514.93 (0.78) Benzoin 27.03 77.28 369.96 (1.00) 21.01 60.07 475.96 (0.95...Xanthone I x 104 3 x 103 2 x 10 2 -3 Photosensitizer x = 318-320 nm x 2 340-345 nm Benzoin 310 -- x-Methyl benzoin 200 -- X-Hydroxymethyl benzoin -- 150... Benzoin isopropyl ether -- 230 Benzoin phenyl ether -- 250 (a) From: V. 0. McGinniss, in "Oevelopments in Polymer Photochemistry - 3", N. S. Allen, Ed

Halogen bonding in solution: thermodynamics and applications.

PubMed

Beale, Thomas M; Chudzinski, Michael G; Sarwar, Mohammed G; Taylor, Mark S

2013-02-21

Halogen bonds are noncovalent interactions in which covalently bound halogens act as electrophilic species. The utility of halogen bonding for controlling self-assembly in the solid state is evident from a broad spectrum of applications in crystal engineering and materials science. Until recently, it has been less clear whether, and to what extent, halogen bonding could be employed to influence conformation, binding or reactivity in the solution phase. This tutorial review summarizes and interprets solution-phase thermodynamic data for halogen bonding interactions obtained over the past six decades and highlights emerging applications in molecular recognition, medicinal chemistry and catalysis.

Permeability of blood-brain barrier in macaque model of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced Parkinson disease.

PubMed

Thiollier, Thibaud; Wu, Caisheng; Contamin, Hugues; Li, Qin; Zhang, Jinlan; Bezard, Erwan

2016-06-01

Brain bioavailability of drugs developed to address central nervous system diseases is classically documented through cerebrospinal fluid collected in normal animals, i.e., through an approximation as there are fundamental differences between cerebrospinal fluid and tissue contents. The fact that disease might affect brain availability of drugs is almost never considered at this stage although several conditions are associated with blood-brain barrier damage. Building upon our expertise in Parkinson's disease translational research, the present study addressed this gap comparing plasma and cerebrospinal fluid bioavailability of l-3,4-dihydroxyphenylalanine, carbamazepine, quinidine, lovastatin, and simvastatin, in healthy and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-treated macaques, the gold standard model of Parkinson's disease. The drugs were selected based upon their differential transport across the blood-brain barrier. Interestingly, brain bioavailability of quinidine was decreased while others were unaffected. Pharmacokinetics and pharmacodynamics experiments of drugs addressing Parkinson's disease might thus be performed in healthy animals unless the drugs are known to interact with the organic cation transporter. © 2016 Wiley Periodicals, Inc.

Adsorption of halogens on metal surfaces

NASA Astrophysics Data System (ADS)

Andryushechkin, B. V.; Pavlova, T. V.; Eltsov, K. N.

2018-06-01

This paper presents a review of the experimental and theoretical investigations of halogen interaction with metal surfaces. The emphasis was placed on the recent measurements performed with a scanning tunneling microscope in combination with density functional theory calculations. The surface structures formed on metal surface after halogen interaction are classified into three groups: chemisorbed monolayer, surface halide, bulk-like halide. Formation of monolayer structures is described in terms of surface phase transitions. Surface halide phases are considered to be intermediates between chemisorbed halogen and bulk halide. The modern theoretical approaches in studying the dynamics of metal halogenation reactions are also presented.

Halogenated solvent remediation

DOEpatents

Sorenson, Kent S.

2004-08-31

Methods for enhancing bioremediation of ground water contaminated with nonaqueous halogenated solvents are disclosed. A preferred method includes adding a composition to the ground water wherein the composition is an electron donor for microbe-mediated reductive dehalogenation of the halogenated solvents and enhances mass transfer of the halogenated solvents from residual source areas into the aqueous phase of the ground water. Illustrative compositions effective in these methods include surfactants such as C.sub.2 -C.sub.4 carboxylic acids and hydroxy acids, salts thereof, esters of C.sub.2 -C.sub.4 carboxylic acids and hydroxy acids, and mixtures thereof. Especially preferred compositions for use in these methods include lactic acid, salts of lactic acid, such as sodium lactate, lactate esters, and mixtures thereof. The microbes are either indigenous to the ground water, or such microbes can be added to the ground water in addition to the composition.

Determination of 3-O- and 4-O-methylated monosaccharide constituents in snail glycans.

PubMed

Stepan, Herwig; Bleckmann, Christina; Geyer, Hildegard; Geyer, Rudolf; Staudacher, Erika

2010-07-02

The N- and O-glycans of Arianta arbustorum, Achatina fulica, Arion lusitanicus and Planorbarius corneus were analysed for their monosaccharide pattern by reversed-phase HPLC after labelling with 2-aminobenzoic acid or 3-methyl-1-phenyl-2-pyrazolin-5-one and by gas chromatography-mass spectrometry. Glucosamine, galactosamine, mannose, galactose, glucose, fucose and xylose were identified. Furthermore, three different methylated sugars were detected: 3-O-methyl-mannose and 3-O-methyl-galactose were confirmed to be a common snail feature; 4-O-methyl-galactose was detected for the first time in snails. Copyright 2010 Elsevier Ltd. All rights reserved.

Developmental toxicity evaluation of inhaled tertiary amyl methyl ether in mice and rats.

PubMed

Welsch, Frank; Elswick, Barbara; James, R Arden; Marr, Melissa C; Myers, Christina B; Tyl, Rochelle W

2003-01-01

This evaluation was part of a much more comprehensive testing program to characterize the mammalian toxicity potential of the gasoline oxygenator additive tertiary amyl methyl ether (TAME), and was initiated upon a regulatory agency mandate. A developmental toxicity hazard identification study was conducted by TAME vapor inhalation exposure in two pregnant rodent species. Timed-pregnant CD(Sprague-Dawley) rats and CD-1 mice, 25 animals per group, inhaled TAME vapors containing 0, 250, 1500 or 3500 ppm for 6 h a day on gestational days 6-16 (mice) or 6-19 (rats). The developmental toxicity hazard potential was evaluated following the study design draft guidelines and end points proposed by the United States Environmental Protection Agency. Based on maternal body weight changes during pregnancy, the no-observable-adverse-effect level (NOAEL) was 250 ppm for maternal toxicity in rats and 1500 ppm for developmental toxicity in rats using the criterion of near-term fetal body weights. In mice, more profound developmental toxicity was present than in rats, at both 1500 and 3500 ppm. At the highest concentration, mouse litters revealed more late fetal deaths, significantly reduced fetal body weights per litter and increased incidences of cleft palate (classified as an external malformation), as well as enlarged lateral ventricles of the cerebrum (a visceral variation). At 1500 ppm, mouse fetuses also exhibited an increased incidence of cleft palate and the dam body weights were reduced. Therefore, the NOAEL for the mouse maternal and developmental toxicity was 250 ppm under the conditions of this study. Copyright 2003 John Wiley & Sons, Ltd.

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

PubMed

Finneran, K T; Lovley, D R

2001-05-01

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

Acetaminophen and aspirin inhibit superoxide anion generation and lipid peroxidation, and protect against 1-methyl-4-phenyl pyridinium-induced dopaminergic neurotoxicity in rats.

PubMed

Maharaj, D S; Saravanan, K S; Maharaj, H; Mohanakumar, K P; Daya, S

2004-04-01

We assessed the antioxidant activity of non-narcotic analgesics, acetaminophen and aspirin in rat brain homogenates and neuroprotective effects in vivo in rats intranigrally treated with 1-methyl-4-phenyl pyridinium (MPP+). Both drugs inhibited cyanide-induced superoxide anion generation, as well as lipid peroxidation in rat brain homogenates, the combination of the agents resulting in a potentiation of this effect. Acetaminophen or aspirin when administered alone or in combination, did not alter dopamine (DA) levels in the forebrain or in the striatum. Intranigral infusion of MPP+ in rats caused severe depletion of striatal DA levels in the ipsilateral striatum in rats by the third day. Systemic post-treatment of acetaminophen afforded partial protection, whereas similar treatment of aspirin resulted in complete blockade of MPP+-induced striatal DA depletion. While these findings suggest usefulness of non-narcotic analgesics in neuroprotective therapy in neurodegenerative diseases, aspirin appears to be a potential candidate in prophylactic as well as in adjuvant therapy in Parkinson's disease.

The application of silicalite-1/fly ash cenosphere (S/FAC) zeolite composite for the adsorption of methyl tert-butyl ether (MTBE).

PubMed

Lu, Jia; Xu, Fang; Wang, Deju; Huang, Jue; Cai, Weimin

2009-06-15

Silicalite-1/fly ash cenosphere (S/FAC) zeolite composite has been applied for batch adsorption of methyl tert-butyl ether (MTBE) from water systems. Here the key experimental conditions, including the ratio of initial MTBE concentration to the amount weight of S/FAC, adsorption time and temperature, have been discussed in detail. The results show that approximately 93-95% MTBE could be adsorbed with initial concentration of MTBE solution 1000 microg l(-1). The column flow-through experiments also prove the high capacity of S/FAC composite for MTBE removal. The distinct advantages of S/FAC zeolite composite as adsorbent lie in (1) enhanced adsorption rate and capacity based on hierarchical micro and meso/macroporosity of S/FAC; (2) more easily operation and recycling process by assembly of nano-sized silicalite-1 zeolite on FAC support.

Traceable atomic force microscopy of high-quality solvent-free crystals of [6,6]-phenyl-C61-butyric acid methyl ester

NASA Astrophysics Data System (ADS)

Lazzerini, Giovanni Mattia; Paternò, Giuseppe Maria; Tregnago, Giulia; Treat, Neil; Stingelin, Natalie; Yacoot, Andrew; Cacialli, Franco

2016-02-01

We report high-resolution, traceable atomic force microscopy measurements of high-quality, solvent-free single crystals of [6,6]-phenyl-C61-butyric acid methyl ester (PCBM). These were grown by drop-casting PCBM solutions onto the spectrosil substrates and by removing the residual solvent in a vacuum. A home-built atomic force microscope featuring a plane mirror differential optical interferometer, fiber-fed from a frequency-stabilized laser (emitting at 632.8 nm), was used to measure the crystals' height. The optical interferometer together with the stabilized laser provides traceability (via the laser wavelength) of the vertical measurements made with the atomic force microscope. We find that the crystals can conform to the surface topography, thanks to their height being significantly smaller compared to their lateral dimensions (namely, heights between about 50 nm and 140 nm, for the crystals analysed, vs. several tens of microns lateral dimensions). The vast majority of the crystals are flat, but an isolated, non-flat crystal provides insights into the growth mechanism and allows identification of "molecular terraces" whose height corresponds to one of the lattice constants of the single PCBM crystal (1.4 nm) as measured with X-ray diffraction.

What’s New in Enzymatic Halogenations

PubMed Central

Fujimori, Danica Galoniæ; Walsh, Christopher T.

2007-01-01

Summary The halogenation of thousands of natural products occurs during biosynthesis and often confers important functional properties. While haloperoxidases had been the default paradigm for enzymatic incorporation of halogens, via X+ equivalents into organic scaffolds, a combination of microbial genome sequencing, enzymatic studies and structural biology have provided deep new insights into enzymatic transfer of halide equivalents in three oxidation states. These are: (1) the halide ions (X−) abundant in nature, (2) halogen atoms (X•), and (3) the X+ equivalents. The mechanism of halogen incorporation is tailored to the electronic demands of specific substrates and involves enzymes with distinct redox coenzyme requirements. PMID:17881282

Halogenated arsenenes as Dirac materials

NASA Astrophysics Data System (ADS)

Tang, Wencheng; Sun, Minglei; Ren, Qingqiang; Wang, Sake; Yu, Jin

2016-07-01

Arsenene is the graphene-like arsenic nanosheet, which has been predicted very recently [S. Zhang, Z. Yan, Y. Li, Z. Chen, and H. Zeng, Angewandte Chemie, 127 (2015) 3155-3158]. Using first-principles calculations, we systematically investigate the structures and electronic properties of fully-halogenated arsenenes. Formation energy analysis reveals that all the fully-halogenated arsenenes except iodinated arsenene are energetically favorable and could be synthesized. We have revealed the presence of Dirac cone in fully-halogenated arsenene compounds. They may have great potential applications in next generation of high-performance devices.

A Base-Resistant Metalloporphyrin Metal–Organic Framework for C–H Bond Halogenation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lv, Xiu-Liang; Wang, Kecheng; Wang, Bin

A base-resistant porphyrin metal–organic framework (MOF), namely PCN-602 has been constructed with 12-connected [Ni 8(OH) 4(H 2O) 2Pz 12] (Pz = pyrazolate) cluster and a newly designed pyrazolate-based porphyrin ligand, 5,10,15,20-tetrakis(4-(pyrazolate-4-yl)phenyl)porphyrin under the guidance of the reticular synthesis strategy. Besides its robustness in hydroxide solution, PCN-602 also shows excellent stability in aqueous solutions of F –, CO 3 2–, and PO 4 3– ions. Interestingly, the Mn 3+-porphyrinic PCN-602, as a recyclable MOF catalyst, presents high catalytic activity for the C–H bond halogenation reaction in a basic system, significantly outperforming its homogeneous counterpart. For the first time, a porphyrinic MOFmore » was thus used as an efficient catalyst in a basic solution with coordinating anions, to the best of our knowledge.« less

The temporal and spatial variability of halogenated trace gases in the upper troposphere.

NASA Astrophysics Data System (ADS)

Oram, D.; O'Sullivan, D.; Brenninkmeijer, C.; van Velthoven, P.; Sturges, W.

2007-12-01

Halogenated trace gases play an important role in stratospheric and tropospheric chemistry, particularly affecting ozone concentrations. In addition they have direct and indirect effects on radiative forcing, and impact on tropospheric reactivity. Data from the CARIBIC project (Civil Aircraft for Regular Investigation of the Atmosphere Based on an Instrumented Container) have been used in conjunction with back-trajectory analysis to further our understanding of the chemical composition, inter-hemispheric distribution and source regions of halogenated compounds in the upper troposphere and lower stratosphere. Whole air samples collected within CARIBIC, have been analyzed using gas chromatography mass spectrometry for around 35 halocarbons and related trace gases, among them many potent greenhouse gases and species important for ozone depletion. The large spatial and temporal coverage of the CARIBIC project has enabled new work to be done investigating recent inter-annual trends in the CFCs, halons, and other anthropogenic halocarbons, as well as identifying clear inter-hemispheric and seasonal variability for a number of species, such as methylene chloride, HCFCs, methyl chloride, methyl bromide, methyl iodide and several reactive short lived bromo and chloro carbons. In this paper results from the CARIBIC flights to China and the Philippines will be highlighted, to discuss anthropogenic emissions of ozone depleting and greenhouse gases, from Asia and Africa. Data from flights to South America will also be presented. As production and consumption of many of these substances are being phased out in Europe and North America, emissions from Asia, Africa and also South America are becoming increasingly more important. Emissions from these regions are also of interest, as the most significant sources are often collocated with regions of convection in the tropics and sub-tropics. Thus enabling a greater proportion of the substances emitted to reach the stratosphere, where

Negative polarity of phenyl-C{sub 61} butyric acid methyl ester adjacent to donor macromolecule domains

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alley, Olivia J.; Dawidczyk, Thomas J.; Hardigree, Josué F. Martínez

2015-01-19

Interfacial fields within organic photovoltaics influence the movement of free charge carriers, including exciton dissociation and recombination. Open circuit voltage (V{sub oc}) can also be dependent on the interfacial fields, in the event that they modulate the energy gap between donor HOMO and acceptor LUMO. A rise in the vacuum level of the acceptor will increase the gap and the V{sub oc}, which can be beneficial for device efficiency. Here, we measure the interfacial potential differences at donor-acceptor junctions using Scanning Kelvin Probe Microscopy, and quantify how much of the potential difference originates from physical contact between the donor andmore » acceptor. We see a statistically significant and pervasive negative polarity on the phenyl-C{sub 61} butyric acid methyl ester (PCBM) side of PCBM/donor junctions, which should also be present at the complex interfaces in bulk heterojunctions. This potential difference may originate from molecular dipoles, interfacial interactions with donor materials, and/or equilibrium charge transfer due to the higher work function and electron affinity of PCBM. We show that the contact between PCBM and poly(3-hexylthiophene) doubles the interfacial potential difference, a statistically significant difference. Control experiments determined that this potential difference was not due to charges trapped in the underlying substrate. The direction of the observed potential difference would lead to increased V{sub oc}, but would also pose a barrier to electrons being injected into the PCBM and make recombination more favorable. Our method may allow unique information to be obtained in new donor-acceptor junctions.« less

Methyl tertiary-butyl ether: studies for potential human health hazards.

PubMed

McGregor, Douglas

2006-04-01

When methyl tertiary-butyl ether (MTBE) in gasoline was first introduced to reduce vehicle exhaust emissions and comply with the Clean Air Act, in the United States, a pattern of complaints emerged characterised by seven "key symptoms." Later, carefully controlled volunteer studies did not confirm the existence of the specific key symptoms, although one study of self-reported sensitive (SRS) people did suggest that a threshold at about 11-15% MTBE in gasoline may exist for SRSs in total symptom scores. Neurobehavioral and psychophysiological studies on volunteers, including SRSs, found no adverse responses associated with MTBE at likely exposure levels. MTBE is well and rapidly absorbed following oral and inhalation exposures. Cmax values for MTBE are achieved almost immediately after oral dosing and within 2 h of continuous inhalation. It is rapidly eliminated, either by exhalation as unchanged MTBE or by urinary excretion of its less volatile metabolites. Metabolism is more rapid humans than in rats, for both MTBE and tert-butyl alcohol (TBA), its more persistent primary metabolite. The other primary metabolite, formaldehyde, is detoxified at a rate very much greater than its formation from MTBE. MTBE has no specific effects on reproduction or development, or on genetic material. Neurological effects were observed only at very high concentrations. In carcinogenicity studies of MTBE, TBA, and methanol (included as an endogenous precursor of formaldehyde, without the presence of TBA), some increases in tumor incidence have been observed, but consistency of outcome was lacking and even some degree of replication was observed in only three cases, none of which had human relevance: alpha(2u)-globulin nephropathy-related renal tubule cell adenoma in male rats; Leydig-cell adenoma in male rats, but not in mice, which provide the better model of the human disease; and B-cell-derived lymphoma/leukemia of doubtful pathogenesis that arose mainly in lungs of orally dosed

Corrigendum to "Synthesis, structural features, and methyl methacrylate polymerisation of binuclear zinc(II) complexes with tetradentate pyrazolyl ligands" [J. Mol. Struct. 1063 (2014) 70-76

NASA Astrophysics Data System (ADS)

Kim, Sunghoon; Kim, Dongil; Lee, Ha-Jin; Lee, Hyosun

2015-05-01

The authors regret to inform that 4,4‧-bis-(N,N-di(1H-pyrazolyl-1-methyl)phenyl)methane (L2) and its binuclear 4,4‧-bis-(N,N-di-(1H-pyrazolyl-1-methyl)phenyl)methane(dichloro)Zn(II) complex, namely, [L2Zn2Cl4] in the paper were published as the thesis for the degree of master in the Department of Chemistry at Kyungpook National University in 2003.

Ionic-liquid-mediated poly(dimethylsiloxane)- grafted carbon nanotube fiber prepared by the sol-gel technique for the head space solid-phase microextraction of methyl tert-butyl ether using GC.

PubMed

Vatani, Hossein; Yazdi, Ali Sarafraz

2014-01-01

A headspace solid-phase microextraction method was developed for the preconcentration and extraction of methyl tert-butyl ether. An ionic-liquid-mediated multiwalled carbon nanotube-poly(dimethylsiloxane) hybrid coating, which was prepared by covalent functionalization of multiwalled carbon nanotubes with hydroxyl-terminated poly(dimethylsiloxane) using the sol-gel technique, was used as solid-phase microextraction adsorbent. This innovative fiber exhibited a highly porous surface structure, high thermal stability (at least 320°C) and long lifespan (over 210 uses). Potential factors affecting the extraction efficiency were optimized. Under the optimum conditions, the method LOD (S/N = 3) was 0.007 ng/mL and the LOQ (S/N = 10) was 0.03 ng/mL. The calibration curve was linear in the range of 0.03-200 ng/mL. The RSDs for one fiber (repeatability, n = 5) at three different concentrations (0.05, 1, and 150 ng/mL) were 5.1, 4.2, and 4.6% and for the fibers obtained from different batches (reproducibility, n = 3) were 6.5, 5.9, and 6.3%, respectively. The developed method was successfully applied to the determination of methyl tert-butyl ether in different real water samples on three consecutive days. The relative recoveries for the spiked samples with 0.05, 1, and 150 ng/mL were between 94-104%. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Antichaperone activity and heme degradation effect of methyl tert-butyl ether (MTBE) on normal and diabetic hemoglobins.

PubMed

Najdegerami, Ismaeil Hossein; Maghami, Parvaneh; Sheikh-Hasani, Vahid; Hosseinzadeh, Ghader; Sheibani, Nader; Moosavi-Movahedi, Ali A

2017-05-01

Because of the extensive use of methyl tert-butyl ether (MTBE) as an additive to increase the octane quality of gasoline, the environmental pollution by this compound has increased in recent decades. Environmental release of MTBE may lead to its entry to the blood stream through inhalation or drinking of contaminated water, and its interactions with biological molecules such as proteins. The present study was proposed to comparatively investigate the interactions of MTBE with hemoglobin (Hb) from diabetic and nondiabetic individuals using various spectroscopic methods including UV-visible, fluorescence, chemiluminescence, and circular dichroism. These results demonstrated the effects of MTBE on heme degradation of Hb and the reaction of these degradation products with water generating reactive oxygen species. Interaction of Hb with MTBE enhanced its aggregation rate and decreased lag time, indicating the antichaperone activity of MTBE upon interaction with Hb. Furthermore, the diabetic Hb showed more severe effects of MTBE, including heme degradation, reactive oxygen species production, unfolding, and antichaperone behavior than the nondiabetic Hb. The results from molecular docking suggested that the special interaction site of MTBE in the vicinity of Hb heme group is responsible for heme degradation. Copyright © 2016 John Wiley & Sons, Ltd.

Oxime Ethers of (E)-11-Isonitrosostrychnine as Highly Potent Glycine Receptor Antagonists.

PubMed

Mohsen, Amal M Y; Mandour, Yasmine M; Sarukhanyan, Edita; Breitinger, Ulrike; Villmann, Carmen; Banoub, Maha M; Breitinger, Hans-Georg; Dandekar, Thomas; Holzgrabe, Ulrike; Sotriffer, Christoph; Jensen, Anders A; Zlotos, Darius P

2016-12-23

A series of (E)-11-isonitrosostrychnine oxime ethers, 2-aminostrychnine, (strychnine-2-yl)propionamide, 18-oxostrychnine, and N-propylstrychnine bromide were synthesized and evaluated pharmacologically at human α1 and α1β glycine receptors in a functional fluorescence-based and a whole-cell patch-clamp assay and in [ 3 H]strychnine binding studies. 2-Aminostrychnine and the methyl, allyl, and propargyl oxime ethers were the most potent α1 and α1β antagonists in the series, displaying IC 50 values similar to those of strychnine at the two receptors. Docking experiments to the strychnine binding site of the crystal structure of the α3 glycine receptor indicated the same orientation of the strychnine core for all analogues. For the most potent oxime ethers, the ether substituent was accommodated in a lipophilic receptor binding pocket. The findings identify the oxime hydroxy group as a suitable attachment point for linking two strychnine pharmacophores by a polymethylene spacer and are, therefore, important for the design of bivalent ligands targeting glycine receptors.

Metal halogen battery construction with improved technique for producing halogen hydrate

DOEpatents

Fong, Walter L.; Catherino, Henry A.; Kotch, Richard J.

1983-01-01

An improved electrical energy storage system comprising, at least one cell having a positive electrode and a negative electrode separated by aqueous electrolyte, a store means wherein halogen hydrate is formed and stored as part of an aqueous material having a liquid level near the upper part of the store, means for circulating electrolyte through the cell, conduit means for transmitting halogen gas formed in the cell to a hydrate forming apparatus associated with the store, said hydrate forming apparatus including, a pump to which there is introduced quantities of the halogen gas and chilled water, said pump being located in the store and an outlet conduit leading from the pump and being substantially straight and generally vertically disposed and having an exit discharge into the gas space above the liquid level in the store, and wherein said hydrate forming apparatus is highly efficient and very resistant to plugging or jamming. The disclosure also relates to an improved method for producing chlorine hydrate in zinc chlorine batteries.

Growth and characterization of an organic single crystal: 2-[2-(4-Diethylamino-phenyl)-vinyl]-1-methyl-pyridinium iodide

NASA Astrophysics Data System (ADS)

Senthil, K.; Kalainathan, S.; Ruban Kumar, A.

Optically transparent crystal of the organic salt DEASI (2-[2-(4-Diethylamino-phenyl)-vinyl]-1-methyl-pyridinium iodide) has been synthesized by using knoevenagel condensation reaction method. The synthesized material has been purified by successfully recrystallization process. Single crystals of DEASI have been grown by slow evaporation technique at room temperature. The solubility of the title material has been determined at different temperature in acetonitrile/methanol mixture. The cell parameters and crystallinity of the title crystal were determined by single crystal XRD. The powder diffraction was carried out to study the reflection plane of the grown crystal and diffraction peaks were indexed. The presence of different functional groups in the crystal was confirmed by Fourier transform infrared (FTIR) analysis. 1H NMR spectrum was recorded to confirm the presence of hydrogen nuclei in the synthesized material. The optical property of the title crystal was studied by UV-Vis-NIR spectroscopic analysis. The melting point and thermal property of DEASI were studied using TGA/DSC technique. The Vicker’s hardness (Hv) was carried out to know the category. The dielectric constant and dielectric loss of the compound decreases with an increase in frequencies. Chemical etching studies showed that the DEASI grows in the two dimensional growth mechanisms. The Kurtz-Perry powder second harmonic generation (SHG) test has done for title crystal.

Growth and characterization of an organic single crystal: 2-[2-(4-diethylamino-phenyl)-vinyl]-1-methyl-pyridinium iodide.

PubMed

Senthil, K; Kalainathan, S; Ruban Kumar, A

2014-05-05

Optically transparent crystal of the organic salt DEASI (2-[2-(4-Diethylamino-phenyl)-vinyl]-1-methyl-pyridinium iodide) has been synthesized by using knoevenagel condensation reaction method. The synthesized material has been purified by successfully recrystallization process. Single crystals of DEASI have been grown by slow evaporation technique at room temperature. The solubility of the title material has been determined at different temperature in acetonitrile/methanol mixture. The cell parameters and crystallinity of the title crystal were determined by single crystal XRD. The powder diffraction was carried out to study the reflection plane of the grown crystal and diffraction peaks were indexed. The presence of different functional groups in the crystal was confirmed by Fourier transform infrared (FTIR) analysis. (1)H NMR spectrum was recorded to confirm the presence of hydrogen nuclei in the synthesized material. The optical property of the title crystal was studied by UV-Vis-NIR spectroscopic analysis. The melting point and thermal property of DEASI were studied using TGA/DSC technique. The Vicker's hardness (Hv) was carried out to know the category. The dielectric constant and dielectric loss of the compound decreases with an increase in frequencies. Chemical etching studies showed that the DEASI grows in the two dimensional growth mechanisms. The Kurtz-Perry powder second harmonic generation (SHG) test has done for title crystal. Copyright © 2014 Elsevier B.V. All rights reserved.

Risk characterization of methyl tertiary butyl ether (MTBE) in tap water.

PubMed

Stern, B R; Tardiff, R G

1997-12-01

Methyl tertiary butyl ether (MTBE) can enter surface water and groundwater through wet atmospheric deposition or as a result of fuel leaks and spills. About 30% of the U.S. population lives in areas where MTBE is in regular use. Ninety-five percent of this population is unlikely to be exposed to MTBE in tap water at concentrations exceeding 2 ppb, and most will be exposed to concentrations that are much lower and may be zero. About 5% of this population may be exposed to higher levels of MTBE in tap water, resulting from fuel tank leaks and spills into surface or groundwater used for potable water supplies. This paper describes the concentration ranges found and anticipated in surface and groundwater, and estimates the distribution of doses experienced by humans using water containing MTBE to drink, prepare food, and shower/bathe. The toxic properties (including potency) of MTBE when ingested, inhaled, and in contact with the skin are summarized. Using a range of human toxic potency values derived from animal studies, margins of exposure (MOE) associated with alternative chronic exposure scenarios are estimated to range from 1700 to 140,000. Maximum concentrations of MTBE in tap water anticipated not to cause adverse health effects are determined to range from 700 to 14,000 ppb. The results of this analysis demonstrate that no health risks are likely to be associated with chronic and subchronic human exposures to MTBE in tap water. Although some individuals may be exposed to very high concentrations of MTBE in tap water immediately following a localized spill, these exposures are likely to be brief in duration due to large-scale dilution and rapid volatilization of MTBE, the institution of emergency response and remediation measures to minimize human exposures, and the low taste and odor thresholds of MTBE which ensure that its presence in tap water is readily detected at concentrations well below the threshold for human injury.

The crystal structure of a new ferrocenyl P,N ligand: 1-[(2,2-di-methyl-hydrazin-1-yl-idene)meth-yl]-1'-(di-phenyl-phospho-rothio-yl)ferrocene.

PubMed

Mouas, Toma Nardjes; Daran, Jean-Claude; Merazig, Hocine; Manoury, Eric

2018-02-01

The asymmetric unit of the title compound, [Fe(C 8 H 11 N 2 )(C 17 H 14 PS)], contains two independent mol-ecules ( A and B ) with very similar conformations. Each mol-ecule is built up from a ferrocene unit substituted in the 1 and 1' positions by a protected sulfur di-phenyl-phosphine and by a di-methyl-hydrazine, -C(H)=N-N(CH 3 ) 2 , fragment. The two independent mol-ecules are linked by a C-H⋯N hydrogen bond. In the crystal, the A - B dimer is linked by a pair of C-H⋯S hydrogen bonds, forming a centrosymmetric four-mol-ecule arrangement. These units are linked by C-H⋯π inter-actions, forming a supra-molecular three-dimensional structure.

Anti-knock quality of sugar derived levulinic esters and cyclic ethers

DOE PAGES

Tian, Miao; McCormick, Robert L.; Luecke, Jon; ...

2017-04-22

Here, the objective of this paper is to investigate the anti-knock quality of sugar-derived levulinic esters (methyl levulinate (ML) and ethyl levulinate (EL)) and cyclic ethers (furfuryl ethyl ether (FEE) and ethyl tetrahydrofurfuryl ether (ETE)). To this end, combustion experiments were carried out in both an engine and a constant volume autoignition device. The results from both apparati demonstrate that ML, EL and FEE have superior anti-knock quality than the reference Euro95 gasoline. ETE, conversely, performed markedly worse than the reference fuel on both setups and might therefore be a more appropriate fuel for compression ignition engines. The main reasonmore » of the distinctions in anti-knock quality can be found in the molecular structure of the neat biofuels. ML and EL are levulinic esters, with a ketone (C=O) functionality and an ester (C(=O)-O) group on the carbon chain. They can readily produce stable intermediates during the auto-ignition process, thereby slowing down the overall reaction rate. The unsaturated cyclic ether (FEE) has very strong ring C-H bonds. However, the saturated cyclic ether (ETE) has weak ring C-H bonds, which facilitate more readily ring opening reactions. Long side chains on the cyclic ethers further accelerate the reaction rate. Importantly for future research, our results suggest that IQT and engine experiments are interchangeable setups with respect to qualitative anti-knock quality evaluation of novel compounds.« less

Anti-knock quality of sugar derived levulinic esters and cyclic ethers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tian, Miao; McCormick, Robert L.; Luecke, Jon

Here, the objective of this paper is to investigate the anti-knock quality of sugar-derived levulinic esters (methyl levulinate (ML) and ethyl levulinate (EL)) and cyclic ethers (furfuryl ethyl ether (FEE) and ethyl tetrahydrofurfuryl ether (ETE)). To this end, combustion experiments were carried out in both an engine and a constant volume autoignition device. The results from both apparati demonstrate that ML, EL and FEE have superior anti-knock quality than the reference Euro95 gasoline. ETE, conversely, performed markedly worse than the reference fuel on both setups and might therefore be a more appropriate fuel for compression ignition engines. The main reasonmore » of the distinctions in anti-knock quality can be found in the molecular structure of the neat biofuels. ML and EL are levulinic esters, with a ketone (C=O) functionality and an ester (C(=O)-O) group on the carbon chain. They can readily produce stable intermediates during the auto-ignition process, thereby slowing down the overall reaction rate. The unsaturated cyclic ether (FEE) has very strong ring C-H bonds. However, the saturated cyclic ether (ETE) has weak ring C-H bonds, which facilitate more readily ring opening reactions. Long side chains on the cyclic ethers further accelerate the reaction rate. Importantly for future research, our results suggest that IQT and engine experiments are interchangeable setups with respect to qualitative anti-knock quality evaluation of novel compounds.« less

OCCURRENCE OF METYL TERT-BUTYL ETHER (MTBE) AT FIVE MARINAS IN LAKE TEXOMA

EPA Science Inventory

Occurrence of methyl tert-butyl ether (MTBE) in five marinas was monitored between June 1999 and November 2000 in Lake Texoma located on the border of Oklahoma and Texas. MTBE is a commonly used gasoline additive and a suspected carcinogen. Lake water was collected at loc...

Crystal structures of 2,3,8,9,14,15-hexa-methyl-5,6,11,12,17,18-hexa-aza-tri-naphthyl-ene and 2,3,8,9,14,15-hexa-phenyl-5,6,11,12,17,18-hexa-za-tri-naphthyl-ene di-chloro-methane disolvate.

PubMed

Fangmann, Pia; Schmidtmann, Marc; Beckhaus, Rüdiger

2018-02-01

The crystal structures of two substituted HATN (hexa-aza-tri-naphthyl-ene) derivatives, namely 2,3,8,9,14,15-hexa-methyl- and 2,3,8,9,14,15-hexa-phenyl-5,6,11,12,17,18- hexa-zatri-naphthyl-ene (HATNMe 6 and HATNPh 6 ), are reported. Whereas the structure of the methyl-substituted derivative (HATNMe 6 ) contains no solvent mol-ecules (C 30 H 24 N 6 ), the hexa-phenyl-substituted structure (HATNPh 6 ) contains two mol-ecules of di-chloro-methane (C 60 H 36 N 6 ·2CH 2 Cl 2 ). This class of planar bridging ligands is known for its electron-deficient systems and its ability to form π-π stacking inter-actions. Indeed, in both crystal structures strong π-π stacking inter-actions are observed, but with different packing features. The di-chloro-methane mol-ecules in the crystal structure of HATNPh 6 are situated in the voids and are involved in C-H⋯N contacts to the nitro-gen atoms of the pyrazine units.

Halogenated compounds from marine algae.

PubMed

Cabrita, Maria Teresa; Vale, Carlos; Rauter, Amélia Pilar

2010-08-09

Marine algae produce a cocktail of halogenated metabolites with potential commercial value. Structures exhibited by these compounds go from acyclic entities with a linear chain to complex polycyclic molecules. Their medical and pharmaceutical application has been investigated for a few decades, however other properties, such as antifouling, are not to be discarded. Many compounds were discovered in the last years, although the need for new drugs keeps this field open as many algal species are poorly screened. The ecological role of marine algal halogenated metabolites has somehow been overlooked. This new research field will provide valuable and novel insight into the marine ecosystem dynamics as well as a new approach to comprehending biodiversity. Furthermore, understanding interactions between halogenated compound production by algae and the environment, including anthropogenic or global climate changes, is a challenging target for the coming years. Research of halogenated metabolites has been more focused on macroalgae than on phytoplankton. However, phytoplankton could be a very promising material since it is the base of the marine food chain with quick adaptation to environmental changes, which undoubtedly has consequences on secondary metabolism. This paper reviews recent progress on this field and presents trends on the role of marine algae as producers of halogenated compounds.

Halogenated Compounds from Marine Algae

PubMed Central

Cabrita, Maria Teresa; Vale, Carlos; Rauter, Amélia Pilar

2010-01-01

Marine algae produce a cocktail of halogenated metabolites with potential commercial value. Structures exhibited by these compounds go from acyclic entities with a linear chain to complex polycyclic molecules. Their medical and pharmaceutical application has been investigated for a few decades, however other properties, such as antifouling, are not to be discarded. Many compounds were discovered in the last years, although the need for new drugs keeps this field open as many algal species are poorly screened. The ecological role of marine algal halogenated metabolites has somehow been overlooked. This new research field will provide valuable and novel insight into the marine ecosystem dynamics as well as a new approach to comprehending biodiversity. Furthermore, understanding interactions between halogenated compound production by algae and the environment, including anthropogenic or global climate changes, is a challenging target for the coming years. Research of halogenated metabolites has been more focused on macroalgae than on phytoplankton. However, phytoplankton could be a very promising material since it is the base of the marine food chain with quick adaptation to environmental changes, which undoubtedly has consequences on secondary metabolism. This paper reviews recent progress on this field and presents trends on the role of marine algae as producers of halogenated compounds. PMID:20948909

Structural Perspective on Enzymatic Halogenation

PubMed Central

2008-01-01

Simple halogen substituents frequently afford key structural features that account for the potency and selectivity of natural products, including antibiotics and hormones. For example, when a single chlorine atom on the antibiotic vancomycin is replaced by hydrogen, the resulting antibacterial activity decreases by up to 70% (HarrisC. M.; KannanR.; KopeckaH.; HarrisT. M.J. Am. Chem. Soc.1985, 107, 6652−6658). This Account analyzes how structure underlies mechanism in halogenases, the molecular machines designed by nature to incorporate halogens into diverse substrates. Traditional synthetic methods of integrating halogens into complex molecules are often complicated by a lack of specificity and regioselectivity. Nature, however, has developed a variety of elegant mechanisms for halogenating specific substrates with both regio- and stereoselectivity. An improved understanding of the biological routes toward halogenation could lead to the development of novel synthetic methods for the creation of new compounds with enhanced functions. Already, researchers have co-opted a fluorinase from the microorganism Streptomyces cattleya to produce 18F-labeled molecules for use in positron emission tomography (PET) (DengH.; CobbS. L.; GeeA. D.; LockhartA.; MartarelloL.; McGlincheyR. P.; O’HaganD.; OnegaM.Chem. Commun.2006, 652−654). Therefore, the discovery and characterization of naturally occurring enzymatic halogenation mechanisms has become an active area of research. The catalogue of known halogenating enzymes has expanded from the familiar haloperoxidases to include oxygen-dependent enzymes and fluorinases. Recently, the discovery of a nucleophilic halogenase that catalyzes chlorinations has expanded the repertoire of biological halogenation chemistry (DongC.; HuangF.; DengH.; SchaffrathC.; SpencerJ. B.; O’HaganD.; NaismithJ. H.Nature2004, 427, 561−56514765200). Structural characterization has provided a basis toward a mechanistic understanding of the specificity

Propyl-5-hydroxy-3-methyl-1-phenyl-1H-pyrazole-4-carbodithioate (HMPC): a new bacteriostatic agent against methicillin-resistant Staphylococcus aureus.

PubMed

Johnston, Tatiana; Van Tyne, Daria; Chen, Roy F; Fawzi, Nicolas L; Kwon, Bumsup; Kelso, Michael J; Gilmore, Michael S; Mylonakis, Eleftherios

2018-05-04

The emergence of Staphylococcus aureus strains resistant to 'last resort' antibiotics compels the development of new antimicrobials against this important human pathogen. We found that propyl 5-hydroxy-3-methyl-1-phenyl-1H-pyrazole-4-carbodithioate (HMPC) shows bacteriostatic activity against S. aureus (MIC = 4 μg/ml) and rescues Caenorhabditis elegans from S. aureus infection. Whole-genome sequencing of S. aureus mutants resistant to the compound, along with screening of a S. aureus promoter-lux reporter array, were used to explore possible mechanisms of action. All mutants resistant to HMPC acquired missense mutations at distinct codon positions in the global transcriptional regulator mgrA, followed by secondary mutations in the phosphatidylglycerol lysyltransferase fmtC/mprF. The S. aureus promoter-lux array treated with HMPC displayed a luminescence profile that was unique but showed similarity to DNA-damaging agents and/or DNA replication inhibitors. Overall, HMPC is a new anti-staphylococcal compound that appears to act via an unknown mechanism linked to the global transcriptional regulator MgrA.

Independent Evolution of Six Families of Halogenating Enzymes.

PubMed

Xu, Gangming; Wang, Bin-Gui

2016-01-01

Halogenated natural products are widespread in the environment, and the halogen atoms are typically vital to their bioactivities. Thus far, six families of halogenating enzymes have been identified: cofactor-free haloperoxidases (HPO), vanadium-dependent haloperoxidases (V-HPO), heme iron-dependent haloperoxidases (HI-HPO), non-heme iron-dependent halogenases (NI-HG), flavin-dependent halogenases (F-HG), and S-adenosyl-L-methionine (SAM)-dependent halogenases (S-HG). However, these halogenating enzymes with similar biological functions but distinct structures might have evolved independently. Phylogenetic and structural analyses suggest that the HPO, V-HPO, HI-HPO, NI-HG, F-HG, and S-HG enzyme families may have evolutionary relationships to the α/β hydrolases, acid phosphatases, peroxidases, chemotaxis phosphatases, oxidoreductases, and SAM hydroxide adenosyltransferases, respectively. These halogenating enzymes have established sequence homology, structural conservation, and mechanistic features within each family. Understanding the distinct evolutionary history of these halogenating enzymes will provide further insights into the study of their catalytic mechanisms and halogenation specificity.

Independent Evolution of Six Families of Halogenating Enzymes

PubMed Central

Xu, Gangming; Wang, Bin-Gui

2016-01-01

Halogenated natural products are widespread in the environment, and the halogen atoms are typically vital to their bioactivities. Thus far, six families of halogenating enzymes have been identified: cofactor-free haloperoxidases (HPO), vanadium-dependent haloperoxidases (V-HPO), heme iron-dependent haloperoxidases (HI-HPO), non-heme iron-dependent halogenases (NI-HG), flavin-dependent halogenases (F-HG), and S-adenosyl-L-methionine (SAM)-dependent halogenases (S-HG). However, these halogenating enzymes with similar biological functions but distinct structures might have evolved independently. Phylogenetic and structural analyses suggest that the HPO, V-HPO, HI-HPO, NI-HG, F-HG, and S-HG enzyme families may have evolutionary relationships to the α/β hydrolases, acid phosphatases, peroxidases, chemotaxis phosphatases, oxidoreductases, and SAM hydroxide adenosyltransferases, respectively. These halogenating enzymes have established sequence homology, structural conservation, and mechanistic features within each family. Understanding the distinct evolutionary history of these halogenating enzymes will provide further insights into the study of their catalytic mechanisms and halogenation specificity. PMID:27153321

Methyl tert‐butyl ether degradation in the unsaturated zone and the relation between MTBE in the atmosphere and shallow groundwater

USGS Publications Warehouse

Baehr, Arthur L.; Charles, Emmanuel G.; Baker, Ronald J.

2001-01-01

Atmospheric methyl tert‐butyl ether (MTBE) concentrations in southern New Jersey generally exceeded concentrations in samples taken from the unsaturated zone. A simple unsaturated zone transport model indicates that MTBE degradation can explain the attenuation with half‐lives from a few months to a couple of years. Tert‐butyl alcohol (TBA), a possible degradation product of MTBE, was detected in unsaturated‐zone samples at concentrations exceeding atmospheric levels at some sites, suggesting the possible conversion of MTBE to TBA. At sites where MTBE was detected in shallow groundwater, the concentration was typically higher than the overlying unsaturated‐zone concentration. This observation is consistent with outgassing from the aquifer and combined with the unsaturated‐zone attenuation suggests some of the MTBE detections in shallow groundwater are nonatmospheric in origin, coming from leaking tanks, road runoff, or other sources. The identification of sources of MTBE in groundwater and attenuation mechanisms through the hydrologic cycle is critical in developing an understanding of the long‐term effect of MTBE releases.

Study of improved resins for advanced supersonic technology composites. Part 1: Heteroaromatic polymers containing ether groups. Part 2: Curing chemistry of aromatic polymers and composite studies

NASA Technical Reports Server (NTRS)

Takekoshi, T.; Hillig, W. B.; Mellinger, G. A.

1975-01-01

Fourteen ether-containing, aromatic dianhydrides have been synthesized from N-phenyl-3 or 4-nitrophthalimide and various bisphenols. The process involves nucleophilic displacement of activated nitro groups with bisphenolate ions. Ether-containing dianhydrides were indefinitely stable in the presence of atmospheric moisture. One-step, high temperature solution polymerization of the ether-containing dianhydrides with m-phenylene diamine, 4,4'-oxydianiline and 1, 3-bis(4-aminophenoxy)benzene afforded 42 polyetherimides. The polyetherimides were all soluble in m-cresol except two which were found to be crystalline. The glass transition temperatures of the polyetherimides ranged from 178 to 277 C. Soluble polybenzimidazopyrrolones containing ether groups were also prepared from the same ether-containing dianhydrides and aromatic tetraamines by one-step solution polymerization. Using low molecular weight polyetherimides, various thermoset resin systems were developed and tested as matrices for fiber-reinforced composites. The curing chemistry involving reaction of the phthalonitrile group and the o-diaminophenyl group was found to be generally applicable to crosslinking various aromatic polymers other than polyimides.

Blood pharmacokinetics of tertiary amyl methyl ether in male and female F344 rats and CD-1 mice after nose-only inhalation exposure.

PubMed

Sumner, Susan C J; Janszen, Derek B; Asgharian, Bahman; Moore, Timothy A; Bobbitt, Carol M; Fennell, Timothy R

2003-01-01

Interest in understanding the biological behavior of aliphatic ethers has increased owing to their use as gasoline additives. The purpose of this study was to investigate the blood pharmacokinetics of the oxygenate tertiary amyl methyl ether (TAME), its major metabolite tertiary amyl alcohol (TAA) and acetone in rats and mice following inhalation exposure to TAME. Species differences in the area under the curve (AUC) for TAME were significant at each exposure concentration. For rats, the blood TAME AUC increased in proportion with an increase in exposure concentration. For mice, an increase in exposure concentration (100-500 ppm) resulted in a disproportional increase in the TAME AUC. Mice had greater (two- to threefold) blood concentrations of TAA compared with rats following exposure to 2500 or 500 ppm TAME. Mice had a disproportional increase in the TAA AUC with an increase in exposure concentration (100-500 ppm). This difference could result from saturation of a process (e.g. oxidation, glucuronide conjugation) that is involved in the further metabolism of TAA. For each species, gender and exposure concentration, acetone increased during exposure and returned to control values by 16 h following exposure. The source of acetone could be both as a metabolite of TAA or an effect on endogenous metabolism produced by exposure to TAME. Copyright 2003 John Wiley & Sons, Ltd.

Halogen-bonding-triggered supramolecular gel formation

NASA Astrophysics Data System (ADS)

Meazza, Lorenzo; Foster, Jonathan A.; Fucke, Katharina; Metrangolo, Pierangelo; Resnati, Giuseppe; Steed, Jonathan W.

2013-01-01

Supramolecular gels are topical soft materials involving the reversible formation of fibrous aggregates using non-covalent interactions. There is significant interest in controlling the properties of such materials by the formation of multicomponent systems, which exhibit non-additive properties emerging from interaction of the components. The use of hydrogen bonding to assemble supramolecular gels in organic solvents is well established. In contrast, the use of halogen bonding to trigger supramolecular gel formation in a two-component gel (‘co-gel’) is essentially unexplored, and forms the basis for this study. Here, we show that halogen bonding between a pyridyl substituent in a bis(pyridyl urea) and 1,4-diiodotetrafluorobenzene brings about gelation, even in polar media such as aqueous methanol and aqueous dimethylsulfoxide. This demonstrates that halogen bonding is sufficiently strong to interfere with competing gel-inhibitory interactions and create a ‘tipping point’ in gel assembly. Using this concept, we have prepared a halogen bond donor bis(urea) gelator that forms co-gels with halogen bond acceptors.

Cytotoxic Activity and Structure-Activity Relationship of Triazole-Containing Bis(Aryl Ether) Macrocycles.

PubMed

Hernández-Vázquez, Eduardo; Chávez-Riveros, Alejandra; Romo-Pérez, Adriana; Ramírez-Apán, María Teresa; Chávez-Blanco, Alma D; Morales-Bárcenas, Rocío; Dueñas-González, Alfonso; Miranda, Luis D

2018-05-17

Cancer continues to be a worldwide health problem. Certain macrocyclic molecules have become attractive therapeutic alternatives for this disease because of their efficacy and, frequently, their novel mechanisms of action. Herein, we report the synthesis of a series of 20-, 21-, and 22-membered macrocycles containing triazole and bis(aryl ether) moieties. The compounds were prepared by a multicomponent approach from readily available commercial substrates. Notably, some of the compounds displayed interesting cytotoxicity against cancer (PC-3) and breast (MCF-7) cell lines, especially those bearing an aliphatic or a trifluoromethyl substituent on the N-phenyl moiety (IC 50 <13 μm). Additionally, some of the compounds were able to induce apoptosis relative to the solvent control; in particular, (Z)-N-cyclohexyl-7-oxo-6-[4-(trifluoromethyl)phenyl]-1 1 H-3,10-dioxa-6-aza-1(4,1)-triazola-4(1,3),9(1,4)-dibenzenacyclotridecaphane-5-carboxamide (12 f) was the most potent in this regard (22.7 % of apoptosis). © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Natural zinniol derivatives from Alternaria tagetica. Isolation, synthesis, and structure-activity correlation.

PubMed

Gamboa-Angulo, M Marcela; Escalante-Erosa, Fabiola; García-Sosa, Karlina; Alejos-González, Fátima; Delgado-Lamas, Guillermo; Peña-Rodríguez, Luis M

2002-02-27

Two novel phytotoxins, 8-zinniol methyl ether (5) and 8-zinniol acetate (6), in addition to 6-(3',3'-dimethylallyloxy)-4-methoxy-5-methylphthalide (2), 5-(3',3'-dimethylallyloxy)-7-methoxy-6-methylphthalide (3), and the novel metabolites 8-zinniol 2-(phenyl)ethyl ether (4) and 7-zinniol acetate (7) have been identified as natural zinniol derivatives from the organic crude extract of Alternaria tagetica culture filtrates. Using zinniol as the starting material, phytotoxin 5 was synthesized, together with a number of synthetic intermediates (8-13). Both natural and synthetic zinniol derivatives were evaluated in the leaf-spot bioassay against marigold leaves (Tagetes erecta).

Density functional theory study of the reaction mechanism for competitive carbon-hydrogen and carbon-halogen bond activations catalyzed by transition metal complexes.

PubMed

Yang, Xinzheng; Hall, Michael B

2009-03-12

Carbon-hydrogen and carbon-halogen bond activations between halobenzenes and metal centers were studied by density functional theory with the nonempirical meta-GGA Tao-Perdew-Staroverov-Scuseria functional and an all-electron correlation-consistent polarized valence double-zeta basis set. Our calculations demonstrate that the hydrogen on the metal center and halogen in halobenzene could exchange directly through a kite-shaped transition state. Transition states with this structure were previously predicted to have high energy barriers (J. Am. Chem. Soc. 2005, 127, 279), and this prediction misled others in proposing a mechanism for their recent experimental study (J. Am. Chem. Soc. 2006, 128, 3303). Furthermore, other halo-carbon activation pathways were found in the detailed mechanism for the competitive reactions between cationic titanium hydride complex [Cp*((t)Bu(3)P=N)TiH](+) and chlorobenzene under different pressure of H(2). These pathways include the ortho-C-H and Ti-H bond activations for the formation and release of H(2) and the indirect C-Cl bond activation via beta-halogen elimination for the movement of the C(6)H(4) ring and the formation of a C-N bond in the observed final product. A new stable isomer of the observed product with a similar total energy and an unexpected bridging between the Cp* ring and the metal center by a phenyl ring is also predicted.

Sulfonimide-containing poly(arylene ether)s and poly(arylene ether sulfone)s, methods for producing the same, and uses thereof

DOEpatents

Hofmann, Michael A.

2006-11-14

The present invention is directed to sulfonimide-containing polymers, specifically sulfonimide-containing poly(arylene ether)s and sulfonimide-containing poly(arylene ether sulfone)s, and processes for making the sulfonimide-containing poly(arylene ether)s and sulfonimide-containing poly(arylene ether sulfone)s, for use conductive membranes and fuel cells.

(Meth­oxy­methyl­idene)di­methyl­aza­nium tetra­phenyl­borate aceto­nitrile monosolvate

PubMed Central

Tiritiris, Ioannis; Saur, Stefan; Kantlehner, Willi

2014-01-01

In the cation of the title salt, C4H10NO+·C24H20B−·C2H3N, the C—N bond lengths are 1.2864 (16), 1.4651 (17) and 1.4686 (16) Å, indicating double- and single-bond character, respectively. The C—O bond length of 1.2978 (15) Å shows double-bond character, pointing towards charge delocalization within the NCO plane of the iminium ion. C—H⋯π inter­actions are present between the methine H atom and two of the phenyl rings of the tetra­phenyl­borate ion. The latter forms an aromatic pocket in which the cation is embedded. The iminium ion is further connected through a C—H⋯N hydrogen bond to the aceto­nitrile mol­ecule. This leads to the formation of a two-dimensional supramolecular pattern along the bc plane. PMID:24765028

Expression of an alkane monooxygenase (alkB) gene and methyl tert-butyl ether co-metabolic oxidation in Pseudomonas citronellolis.

PubMed

Bravo, Ana Luisa; Sigala, Juan Carlos; Le Borgne, Sylvie; Morales, Marcia

2015-04-01

Pseudomonas citronellolis UAM-Ps1 co-metabolically transforms methyl tert-butyl ether (MTBE) to tert-butyl alcohol with n-pentane (2.6 mM), n-octane (1.5 mM) or dicyclopropylketone (DCPK) (4.4 mM), a gratuitous inducer of alkane hydroxylase (AlkB) activity. The reverse transcription quantitative real-time PCR was used to quantify the alkane monooxygenase (alkB) gene expression. The alkB gene was expressed in the presence of n-alkanes and DCPK and MTBE oxidation occurred only in cultures when alkB was transcribed. A correlation between the number of alkB transcripts and MTBE consumption was found (ΜΤΒΕ consumption in μmol = 1.44e(-13) x DNA copies, R(2) = 0.99) when MTBE (0.84 mM) was added. Furthermore, alkB was cloned and expressed into Escherichia coli and the recombinant AlkB had a molecular weight of 42 kDa. This is the first report where the expression of alkB is related to the co-metabolic oxidation of MTBE.

Anionic polymer, poly(methyl vinyl ether-maleic anhydride)-coated beads-based capture of human influenza A and B virus.

PubMed

Sakudo, Akikazu; Baba, Koichi; Tsukamoto, Megumi; Sugimoto, Atsuko; Okada, Takashi; Kobayashi, Takanori; Kawashita, Norihito; Takagi, Tatsuya; Ikuta, Kazuyoshi

2009-01-15

An anionic magnetic beads-based method was developed for the capture of human influenza A and B viruses from nasal aspirates, allantoic fluid and culture medium. A polymer, poly(methyl vinyl ether-maleic anhydride) [poly(MVE-MA)], was used to endow magnetic beads with a negative charge and bioadhesive properties. After incubation with samples containing human influenza virus, the beads were separated from supernatants by applying a magnetic field. The adsorption [corrected] of the virus by the beads was confirmed by hemagglutinin assay, immunochromatography, Western blotting, egg infection, and cell infection. Successful capture was proved using 5 H1N1 influenza A viruses, 10 H3N2 influenza A viruses, and 6 influenza B viruses. Furthermore, the infectivity in chicken embryonated eggs and Madin-Darby canine kidney (MDCK) cells of the captured human influenza virus was similar to that of the total viral quantity of starting materials. Therefore, this method of capture using magnetic beads coated with poly(MVE-MA) can be broadly used for the recovery of infectious human influenza viruses.

Treatment System for Removing Halogenated Compounds from Contaminated Sources

NASA Technical Reports Server (NTRS)

Clausen, Christian A. (Inventor); Yestrebsky, Cherie L. (Inventor); Quinn, Jacqueline W. (Inventor)

2015-01-01

A treatment system and a method for removal of at least one halogenated compound, such as PCBs, found in contaminated systems are provided. The treatment system includes a polymer blanket for receiving at least one non-polar solvent. The halogenated compound permeates into or through a wall of the polymer blanket where it is solubilized with at least one non-polar solvent received by said polymer blanket forming a halogenated solvent mixture. This treatment system and method provides for the in situ removal of halogenated compounds from the contaminated system. In one embodiment, the halogenated solvent mixture is subjected to subsequent processes which destroy and/or degrade the halogenated compound.

Passivation of quartz for halogen-containing light sources

DOEpatents

Falkenstein, Zoran

1999-01-01

Lifetime of halogen containing VUV, UV, visible or IR light sources can be extended by passivating the quartz or glass gas containers with halogens prior to filling the quartz with the halogen and rare gas mixtures used to produce the light.

Effect of fungal mycelia on the HPLC-UV and UV-vis spectrophotometric assessment of mycelium-bound epoxide hydrolase using glycidyl phenyl ether.

PubMed

Dolcet, Marta M; Torres, Mercè; Canela, Ramon

2016-06-25

The use of mycelia as biocatalysts has technical and economic advantages. However, there are several difficulties in obtaining accurate results in mycelium-catalysed reactions. Firstly, sample extraction, indispensable because of the presence of mycelia, can bring into the extract components with a similar structure to that of the analyte of interest; secondly, mycelia can influence the recovery of the analyte. We prepared calibration standards of 3-phenoxy-1,2-propanediol (PPD) in the pure solvent and in the presence of mycelia (spiked before or after extraction) from five fungi (Aspergillus niger, Aspergillus tubingensis, Penicillium aurantiogriseum, Penicillium sp. and Aspergillus terreus). The quantification of PPD was carried out by HPLC-UV and UV-vis spectrophotometry. The manuscript shows that the last method is as accurate as the HPLC method. However, the colorimetric method led to a higher data throughput, which allowed the study of more samples in a shorter time. Matrix effects were evaluated visually from the plotted calibration data and statistically by simultaneously comparing the intercept and slope of calibration curves performed with solvent, post-extraction spiked standards and pre-extraction spiked standards. Significant differences were found between the post- and pre-extraction spiked matrix-matched functions. Pre-extraction spiked matrix-matched functions based on A. tubingensis mycelia, selected as the reference, were validated and used to compensate for low recoveries. These validated functions were successfully applied to the quantification of PPD achieved during the hydrolysis of glycidyl phenyl ether by mycelium-bound epoxide hydrolases and equivalent hydrolysis yields were determined by HPLC-UV and UV-vis spectrophotometry. This study may serve as starting point to implement matrix effects evaluation when mycelium-bound epoxide hydrolases are studied. Copyright © 2016 Elsevier B.V. All rights reserved.

Enhancement of memory margins in the polymer composite of [6,6]-phenyl-C61-butyric acid methyl ester and polystyrene.

PubMed

Sun, Yanmei; Lu, Junguo; Ai, Chunpeng; Wen, Dianzhong; Bai, Xuduo

2016-11-09

Memory devices based on composites of polystyrene (PS) and [6,6]-phenyl-C 61 -butyric acid methyl ester (PCBM) were investigated with bistable resistive switching behavior. Current-voltage (I-V) curves for indium-tin-oxide (ITO)/PS + PCBM/Al devices with 33 wt% PCBM showed non-volatile, rewritable, flash memory properties with a maximum ON/OFF current ratio of 1 × 10 4 , which was 100 times larger than the ON/OFF ratio of the device with 5 wt% PCBM. For ITO/PS + PCBM/Al devices with 33 wt% PCBM, the write-read-erase-read test cycles demonstrated the bistable devices with ON and OFF states at the same voltage. The programmable ON and OFF states endured up to 10 4 read pulses and possessed a retention time of over 10 5 s, indicative of the memory stability of the device. In the OFF state, the I-V curve at lower voltages up to 0.45 V was attributed to the thermionic emission mechanism, and the I-V characteristics in the applied voltage above 0.5 V dominantly followed the space-charge-limited-current behaviors. In the ON state, the curve in the applied voltage range was related to an Ohmic mechanism.

Molecular association via halogen bonding and other weak interactions in the crystal structures of 11-bromo-12-oxo-5β-cholan derivatives

NASA Astrophysics Data System (ADS)

Salunke, Deepak B.; Hazra, Braja G.; Gonnade, Rajesh G.; Pore, Vandana S.; Bhadbhade, Mohan M.

2008-12-01

Methyl 3α,7α-diacetoxy-12-oxo-5β-cholan-24-oate 2, methyl 11α-bromo-3α,7α-diacetoxy-12-oxo-5β-cholan-24-oate 3, methyl 11β-bromo-3α,7α-diacetoxy-12-oxo-5β-cholan-24-oate 4 and methyl 11,11-dibromo-3α,7α-diacetoxy-12-oxo-5β-cholan-24-oate 5 were synthesized. The crystal structures of these molecules were resolved to study the effect of bulky bromine atom in the steroid skeleton of cholic acid with different stereo-chemical orientations at C-11 on the two-dimensional arrangement of molecules and solid-state properties. All the molecules associate only via weak intermolecular interactions in their crystal structures, notable one being the Halogen Bonded assembly (C-Br…O) in 5.

METHOD FOR PRODUCING ISOTOPIC METHANES AND PARTIALLY HALOGENATED DERIVATIVES THEROF

DOEpatents

Frazer, J.W.

1959-08-18

A method is given for producing isotopic methanes and/ or partially halogenated derivatives. Lithium hydride, deuteride, or tritide is reacted with a halogenated methane or with a halogenated methane in combination with free halogen. The process is conveniently carried out by passing a halogenated methane preferably at low pressures or in an admixture with an inert gas through a fixed bed of finely divided lithium hydride heated initially to temperatures of 100 to 200 deg C depending upon the halogenated methane used.

Electrolyte-gated transistors based on phenyl-C61-butyric acid methyl ester (PCBM) films: bridging redox properties, charge carrier transport and device performance.

PubMed

Lan, Tian; Soavi, Francesca; Marcaccio, Massimo; Brunner, Pierre-Louis; Sayago, Jonathan; Santato, Clara

2018-05-24

The n-type organic semiconductor phenyl-C61-butyric acid methyl ester (PCBM), a soluble fullerene derivative well investigated for organic solar cells and transistors, can undergo several successive reversible, diffusion-controlled, one-electron reduction processes. We exploited such processes to shed light on the correlation between electron transfer properties, ionic and electronic transport as well as device performance in ionic liquid (IL)-gated transistors. Two ILs were considered, based on bis(trifluoromethylsulfonyl)imide [TFSI] as the anion and 1-ethyl-3-methylimidazolium [EMIM] or 1-butyl-1-methylpyrrolidinium [PYR14] as the cation. The aromatic structure of [EMIM] and its lower steric hindrance with respect to [PYR14] favor a 3D (bulk) electrochemical doping. As opposed to this, for [PYR14] the doping seems to be 2D (surface-confined). If the n-doping of the PCBM is pursued beyond the first electrochemical process, the transistor current vs. gate-source voltage plots in [PYR14][TFSI] feature a maximum that points to the presence of finite windows of high conductivity in IL-gated PCBM transistors.

Graphene composite for improvement in the conversion efficiency of flexible poly 3-hexyl-thiophene:[6,6]-phenyl C{sub 71} butyric acid methyl ester polymer solar cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chauhan, A. K., E-mail: akchau@barc.gov.in, E-mail: akc.barc@gmail.com; Gusain, Abhay; Jha, P.

2014-03-31

The solution of thin graphene-sheets obtained from a simple ultrasonic exfoliation process was found to chemically interact with [6,6]-phenyl C{sub 71} butyric acid methyl ester (PCBM) molecules. The thinner graphene-sheets have significantly altered the positions of highest occupied molecular orbital and lowest unoccupied molecular orbital of PCBM, which is beneficial for the enhancement of the open circuit voltage of the solar cells. Flexible bulk heterojunction solar cells fabricated using poly 3-hexylthiophene (P3HT):PCBM-graphene exhibited a power conversion efficiency of 2.51%, which is a ∼2-fold increase as compared to those fabricated using P3HT:PCBM. Inclusion of graphene-sheets not only improved the open-circuit voltagemore » but also enhanced the short-circuit current density owing to an improved electron transport.« less

Correlation of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine Neurotoxicity with Blood-Brain Barrier Monoamine Oxidase Activity

NASA Astrophysics Data System (ADS)

Kalaria, Rajesh N.; Mitchell, Mary Jo; Harik, Sami I.

1987-05-01

Systemic administration of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) causes parkinsonism in humans and subhuman primates, but not in rats and many other laboratory animals; mice are intermediate in their susceptibility. Since MPTP causes selective dopaminergic neurotoxicity when infused directly into rat substantia nigra, we hypothesized that systemic MPTP may be metabolized by monoamine oxidase and/or other enzymes in rat brain capillaries and possibly other peripheral organs and thus prevented from reaching its neuronal sites of toxicity. We tested this hypothesis by assessing monoamine oxidase in isolated cerebral microvessels of humans, rats, and mice by measuring the specific binding of [3H]pargyline, an irreversible monoamine oxidase inhibitor, and by estimating the rates of MPTP and benzylamine oxidation. [3H]Pargyline binding to rat cerebral microvessels was about 10-fold higher than to human or mouse microvessels. Also, MPTP oxidation by rat brain microvessels was about 30-fold greater than by human microvessels; mouse microvessels yielded intermediate values. These results may explain, at least in part, the marked species differences in susceptibility to systemic MPTP. They also suggest the potential importance of ``enzyme barriers'' at the blood-brain interface that can metabolize toxins not excluded by structural barriers, and may provide biological bases for developing therapeutic strategies for the prevention of MPTP-induced neurotoxicity and other neurotoxic conditions including, possibly, Parkinson disease.

Organic memory using [6,6]-phenyl-C(61) butyric acid methyl ester: morphology, thickness and concentration dependence studies.

PubMed

Baral, Jayanta K; Majumdar, Himadri S; Laiho, Ari; Jiang, Hua; Kauppinen, Esko I; Ras, Robin H A; Ruokolainen, Janne; Ikkala, Olli; Osterbacka, Ronald

2008-01-23

We report a simple memory device in which the fullerene-derivative [6,6]-phenyl-C(61) butyric acid methyl ester (PCBM) mixed with inert polystyrene (PS) matrix is sandwiched between two aluminum (Al) electrodes. Transmission electron microscopy (TEM) images of PCBM:PS films showed well controlled morphology without forming any aggregates at low weight percentages (<10 wt%) of PCBM in PS. Energy dispersive x-ray spectroscopy (EDX) analysis of the device cross-sections indicated that the thermal evaporation of the Al electrodes did not lead to the inclusion of Al metal nanoparticles into the active PCBM:PS film. Above a threshold voltage of <3 V, independent of thickness, a consistent negative differential resistance (NDR) is observed in devices in the thickness range from 200 to 350 nm made from solutions with 4-10 wt% of PCBM in PS. We found that the threshold voltage (V(th)) for switching from the high-impedance state to the low-impedance state, the voltage at maximum current density (V(max)) and the voltage at minimum current density (V(min)) in the NDR regime are constant within this thickness range. The current density ratio at V(max) and V(min) is more than or equal to 10, increasing with thickness. Furthermore, the current density is exponentially dependent on the longest tunneling jump between two PCBM molecules, suggesting a tunneling mechanism between individual PCBM molecules. This is further supported with temperature independent NDR down to 240 K.

Tannins and Tannin-Related Derivatives Enhance the (Pseudo-)Halogenating Activity of Lactoperoxidase.

PubMed

Gau, Jana; Prévost, Martine; Van Antwerpen, Pierre; Sarosi, Menyhárt-Botond; Rodewald, Steffen; Arnhold, Jürgen; Flemmig, Jörg

2017-05-26

Several hydrolyzable tannins, proanthocyanidins, tannin derivatives, and a tannin-rich plant extract of tormentil rhizome were tested for their potential to regenerate the (pseudo-)halogenating activity, i.e., the oxidation of SCN - to hypothiocyanite - OSCN, of lactoperoxidase (LPO) after hydrogen peroxide-mediated enzyme inactivation. Measurements were performed using 5-thio-2-nitrobenzoic acid in the presence of tannins and related substances in order to determine kinetic parameters and to trace the LPO-mediated - OSCN formation. The results were combined with docking studies and molecular orbital analysis. The - OSCN-regenerating effect of tannin derivatives relates well with their binding properties toward LPO as well as their occupied molecular orbitals. Especially simple compounds like ellagic acid or methyl gallate and the complex plant extract were found as potent enzyme-regenerating compounds. As the (pseudo-)halogenating activity of LPO contributes to the maintenance of oral bacterial homeostasis, the results provide new insights into the antibacterial mode of action of tannins and related compounds. Furthermore, chemical properties of the tested compounds that are important for efficient enzyme-substrate interaction and regeneration of the - OSCN formation by LPO were identified.

Development of sample clean up methods for the analysis of Mycobacterium tuberculosis methyl mycocerosate biomarkers in sputum extracts by gas chromatography–mass spectrometry

PubMed Central

Nicoara, Simona C.; Turner, Nicholas W.; Minnikin, David E.; Lee, Oona Y.-C.; O'Sullivan, Denise M.; McNerney, Ruth; Mutetwa, Reggie; Corbett, Liz E.; Morgan, Geraint H.

2015-01-01

A proof of principle gas chromatography–mass spectrometry method is presented, in combination with clean up assays, aiming to improve the analysis of methyl mycocerosate tuberculosis biomarkers from sputum. Methyl mycocerosates are generated from the transesterification of phthiocerol dimycocerosates (PDIMs), extracted in petroleum ether from sputum of tuberculosis suspect patients. When a high matrix background is present in the sputum extracts, the identification of the chromatographic peaks corresponding to the methyl derivatives of PDIMs analytes may be hindered by the closely eluting methyl ether of cholesterol, usually an abundant matrix constituent frequently present in sputum samples. The purification procedures involving solid phase extraction (SPE) based methods with both commercial Isolute-Florisil cartridges, and purpose designed molecularly imprinted polymeric materials (MIPs), resulted in cleaner chromatograms, while the mycocerosates are still present. The clean-up performed on solutions of PDIMs and cholesterol standards in petroleum ether show that, depending on the solvent mix and on the type of SPE used, the recovery of PDIMs is between 64 and 70%, whilst most of the cholesterol is removed from the system. When applied to petroleum ether extracts from representative sputum samples, the clean-up procedures resulted in recoveries of 36–68% for PDIMs, allowing some superior detection of the target analytes. PMID:25728371

Experimental and computational evidence of halogen bonds involving astatine

NASA Astrophysics Data System (ADS)

Guo, Ning; Maurice, Rémi; Teze, David; Graton, Jérôme; Champion, Julie; Montavon, Gilles; Galland, Nicolas

2018-03-01

The importance of halogen bonds—highly directional interactions between an electron-deficient σ-hole moiety in a halogenated compound and an acceptor such as a Lewis base—is being increasingly recognized in a wide variety of fields from biomedicinal chemistry to materials science. The heaviest halogens are known to form stronger halogen bonds, implying that if this trend continues down the periodic table, astatine should exhibit the highest halogen-bond donating ability. This may be mitigated, however, by the relativistic effects undergone by heavy elements, as illustrated by the metallic character of astatine. Here, the occurrence of halogen-bonding interactions involving astatine is experimentally evidenced. The complexation constants of astatine monoiodide with a series of organic ligands in cyclohexane solution were derived from distribution coefficient measurements and supported by relativistic quantum mechanical calculations. Taken together, the results show that astatine indeed behaves as a halogen-bond donor—a stronger one than iodine—owing to its much more electrophilic σ-hole.

Synthesis of [1-.sup.13C]pyruvic acid], [2-.sup.13C]pyruvic acid], [3-.sup.13C]pyruvic acid] and combinations thereof

DOEpatents

Martinez, Rodolfo A. , Unkefer; Clifford J. , Alvarez; Marc, A [Santa Fe, NM

2012-06-12

The present invention is directed to the labeled compounds, ##STR00001## wherein C* is each either .sup.13C and .sup.12C where at least one C* is .sup.13C, each hydrogen of the methylene group is hydrogen or deuterium, the methyl group includes either zero or three deuterium atoms, Q is sulfide, sulfinyl, or sulfone, Z is an aryl group such as 1-naphthyl, substituted 1-naphthyl, 2-naphthyl, substituted 2-naphthyl, or a phenyl group ##STR00002## wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4 and R.sub.5 are each independently either hydrogen, a C.sub.1-C.sub.4 lower alkyl, a halogen, and an amino group such as NH.sub.2, NHR and NRR' where R and R' are each independently either a C.sub.1-C.sub.4 lower alkyl, a phenyl, and an alkoxy group, and the methyl group can include either zero or three deuterium atoms. The present invention is also directed to the labeled compounds ##STR00003##

Synthesis and Properties of Poly(ether sulfone)s with Clustered Sulfonic Groups for PEMFC Applications under Various Relative Humidity.

PubMed

Lee, Shih-Wei; Chen, Jyh-Chien; Wu, Jin-An; Chen, Kuei-Hsien

2017-03-22

Novel sulfonated poly(ether sulfone) copolymers (S4PH-x-PSs) based on a new aromatic diol containing four phenyl substituents at the 2, 2', 6, and 6' positions of 4,4'-diphenyl ether were synthesized. Sulfonation was found to occur exclusively on the 4 position of phenyl substituents by NMR spectroscopy. The ion exchange capacity (IEC) values can be controlled by adjusting the mole percent (x in S4PH-x-PS) of the new diol. The fully hydrated sulfonated poly(ether sulfone) copolymers had good proton conductivity in the range 0.004-0.110 S/cm at room temperature. The surface morphology of S4PH-x-PSs and Nafion 212 was investigated by atomic force microscopy (tapping-mode) and related to the percolation limit and proton conductivity. Single H 2 /O 2 fuel cell based on S4PH-40-PS loaded with 0.25 mg/cm 2 catalyst (Pt/C) exhibited a peak power density of 462.6 mW/cm 2 , which was close to that of Nafion 212 (533.5 mW/cm 2 ) at 80 °C with 80% RH. Furthermore, fuel cell performance of S4PH-35-PS with various relative humidity was investigated. It was confirmed from polarization curves that the fuel cell performance of S4PH-35-PS was not as high as that of Nafion 212 under fully hydrated state due to higher interfacial resistance between S4PH-35-PS and electrodes. While under low relative humidity (53% RH) at 80 °C, fuel cells based on S4PH-35-PS showed higher peak power density (234.9 mW/cm 2 ) than that (214.0 mW/cm 2 ) of Nafion 212.

Transition from metal-ligand bonding to halogen bonding involving a metal as halogen acceptor a study of Cu, Ag, Au, Pt, and Hg complexes

NASA Astrophysics Data System (ADS)

Oliveira, Vytor; Cremer, Dieter

2017-08-01

Utilizing all-electron Dirac-exact relativistic calculations with the Normalized Elimination of the Small Component (NESC) method and the local vibrational mode approach, the transition from metal-halide to metal halogen bonding is determined for Au-complexes interacting with halogen-donors. The local stretching force constants of the metal-halogen interactions reveal a smooth transition from weak non-covalent halogen bonding to non-classical 3-center-4-electron bonding and finally covalent metal-halide bonding. The strongest halogen bonds are found for dialkylaurates interacting with Cl2 or FCl. Differing trends in the intrinsic halogen-metal bond strength, the binding energy, and the electrostatic potential are explained.

Synthesis, characterization, antimicrobial, DNA-cleavage and antioxidant activities of 3-((5-chloro-2-phenyl-1H-indol-3-ylimino)methyl)quinoline-2(1H)-thione and its metal complexes

NASA Astrophysics Data System (ADS)

Vivekanand, B.; Mahendra Raj, K.; Mruthyunjayaswamy, B. H. M.

2015-01-01

Schiff base 3-((5-chloro-2-phenyl-1H-indol-3-ylimino)methyl)quinoline-2(1H)-thione and its Cu(II), Co(II), Ni(II), Zn(II) and Fe(III), complexes have been synthesized and characterized by elemental analysis, UV-Visible, IR, 1H NMR, 13C NMR and mass spectra, molar conductance, magnetic susceptibility, ESR and TGA data. The ligand and its metal complexes have been screened for their antibacterial activity against Staphylococcus aureus and Pseudomonas aeruginosa, antifungal activity against Aspergillus niger and Aspergillus flavus in minimum inhibition concentration (MIC) by cup plate method respectively, antioxidant activity using 1,1-diphenyl-2-picryl hydrazyl (DPPH), which was compared with that of standard drugs vitamin-C and vitamin-E and DNA cleavage activity using calf-thymus DNA.

Removal of Intermediate Aromatic Halogenated DBPs by Activated Carbon Adsorption: A New Approach to Controlling Halogenated DBPs in Chlorinated Drinking Water.

PubMed

Jiang, Jingyi; Zhang, Xiangru; Zhu, Xiaohu; Li, Yu

2017-03-21

During chlorine disinfection of drinking water, chlorine may react with natural organic matter (NOM) and bromide ion in raw water to generate halogenated disinfection byproducts (DBPs). To mitigate adverse effects from DBP exposure, granular activated carbon (GAC) adsorption has been considered as one of the best available technologies for removing NOM (DBP precursor) in drinking water treatment. Recently, we have found that many aromatic halogenated DBPs form in chlorination, and they act as intermediate DBPs to decompose and form commonly known DBPs including trihalomethanes and haloacetic acids. In this work, we proposed a new approach to controlling drinking water halogenated DBPs by GAC adsorption of intermediate aromatic halogenated DBPs during chlorination, rather than by GAC adsorption of NOM prior to chlorination (i.e., traditional approach). Rapid small-scale column tests were used to simulate GAC adsorption in the new and traditional approaches. Significant reductions of aromatic halogenated DBPs were observed in the effluents with the new approach; the removals of total organic halogen, trihalomethanes, and haloacetic acids by the new approach always exceeded those by the traditional approach; and the effluents with the new approach were considerably less developmentally toxic than those with the traditional approach. Our findings indicate that the new approach is substantially more effective in controlling halogenated DBPs than the traditional approach.

Alkyl ether lipids, ion channels and lipid raft reorganization in cancer therapy.

PubMed

Jaffrès, Paul-Alain; Gajate, Consuelo; Bouchet, Ana Maria; Couthon-Gourvès, Hélène; Chantôme, Aurélie; Potier-Cartereau, Marie; Besson, Pierre; Bougnoux, Philippe; Mollinedo, Faustino; Vandier, Christophe

2016-09-01

Synthetic alkyl lipids, such as the ether lipids edelfosine (1-O-octadecyl-2-O-methyl-rac-glycero-3-phosphocholine) and ohmline (1-O-hexadecyl-2-O-methyl-rac-glycero-3-β-lactose), are forming a class of antitumor agents that target cell membranes to induce apoptosis and to decrease cell migration/invasion, leading to the inhibition of tumor and metastasis development. In this review, we present the structure-activity relationship of edelfosine and ohmline, and we point out differences and similarities between these two amphiphilic compounds. We also discuss the mechanisms of action of these synthetic alkyl ether lipids (involving, among other structures and molecules, membrane domains, Fas/CD95 death receptor signaling, and ion channels), and highlight a key role for lipid rafts in the underlying process. The reorganization of lipid raft membrane domains induced by these alkyl lipids affects the function of death receptors and ion channels, thus leading to apoptosis and/or inhibition of cancer cell migration. The possible therapeutic use of these alkyl lipids and the clinical perspectives for these lipids in prevention or/and treatment of tumor development and metastasis are also discussed. Copyright © 2016 Elsevier Inc. All rights reserved.

The halogen bond: Nature and applications

NASA Astrophysics Data System (ADS)

Costa, Paulo J.

2017-10-01

The halogen bond, corresponding to an attractive interaction between an electrophilic region in a halogen (X) and a nucleophile (B) yielding a R-X⋯B contact, found applications in many fields such as supramolecular chemistry, crystal engineering, medicinal chemistry, and chemical biology. Their large range of applications also led to an increased interest in their study using computational methods aiming not only at understanding the phenomena at a fundamental level, but also to help in the interpretation of results and guide the experimental work. Herein, a succinct overview of the recent theoretical and experimental developments is given starting by discussing the nature of the halogen bond and the latest theoretical insights on this topic. Then, the effects of the surrounding environment on halogen bonds are presented followed by a presentation of the available method benchmarks. Finally, recent experimental applications where the contribution of computational chemistry was fundamental are discussed, thus highlighting the synergy between the lab and modeling techniques.

Hydrogen bond and halogen bond inside the carbon nanotube

NASA Astrophysics Data System (ADS)

Wang, Weizhou; Wang, Donglai; Zhang, Yu; Ji, Baoming; Tian, Anmin

2011-02-01

The hydrogen bond and halogen bond inside the open-ended single-walled carbon nanotubes have been investigated theoretically employing the newly developed density functional M06 with the suitable basis set and the natural bond orbital analysis. Comparing with the hydrogen or halogen bond in the gas phase, we find that the strength of the hydrogen or halogen bond inside the carbon nanotube will become weaker if there is a larger intramolecular electron-density transfer from the electron-rich region of the hydrogen or halogen atom donor to the antibonding orbital of the X-H or X-Hal bond involved in the formation of the hydrogen or halogen bond and will become stronger if there is a larger intermolecular electron-density transfer from the electron-rich region of the hydrogen or halogen atom acceptor to the antibonding orbital of the X-H or X-Hal bond. According to the analysis of the molecular electrostatic potential of the carbon nanotube, the driving force for the electron-density transfer is found to be the negative electric field formed in the carbon nanotube inner phase. Our results also show that the X-H bond involved in the formation of the hydrogen bond and the X-Hal bond involved in the formation of the halogen bond are all elongated when encapsulating the hydrogen bond and halogen bond within the carbon nanotube, so the carbon nanotube confinement may change the blue-shifting hydrogen bond and the blue-shifting halogen bond into the red-shifting hydrogen bond and the red-shifting halogen bond. The possibility to replace the all electron nanotube-confined calculation by the simple polarizable continuum model is also evaluated.

Crystal structures of three 3-chloro-3-methyl-2,6-di­aryl­piperidin-4-ones

PubMed Central

Arulraj, R.; Sivakumar, S.; Kaur, Manpreet; Jasinski, Jerry P.

2017-01-01

The syntheses and crystal structure of 3-chloro-3-methyl-r-2,c-6-di­phenyl­piperidin-4-one, C18H18ClNO, (I), 3-chloro-3-methyl-r-2,c-6-di-p-tolyl­piperidin-4-one, C20H22ClNO, (II), and 3-chloro-3-methyl-r-2,c-6-bis­(4-chloro­phen­yl)piperidin-4-one, C18H16Cl3NO, (III), are described. In each structure, the piperidine ring adopts a chair conformation and dihedral angles between the mean planes of the phenyl rings are 58.4 (2), 73.5 (5) and 78.6 (2)° in (I), (II) and (III), respectively. In the crystals, mol­ecules are linked into C(6) chains by weak N—H⋯O hydrogen bonds and C—H⋯π inter­actions are also observed. PMID:28217321

Enzymatic Halogenation and Dehalogenation Reactions: Pervasive and Mechanistically Diverse.

PubMed

Agarwal, Vinayak; Miles, Zachary D; Winter, Jaclyn M; Eustáquio, Alessandra S; El Gamal, Abrahim A; Moore, Bradley S

2017-04-26

Naturally produced halogenated compounds are ubiquitous across all domains of life where they perform a multitude of biological functions and adopt a diversity of chemical structures. Accordingly, a diverse collection of enzyme catalysts to install and remove halogens from organic scaffolds has evolved in nature. Accounting for the different chemical properties of the four halogen atoms (fluorine, chlorine, bromine, and iodine) and the diversity and chemical reactivity of their organic substrates, enzymes performing biosynthetic and degradative halogenation chemistry utilize numerous mechanistic strategies involving oxidation, reduction, and substitution. Biosynthetic halogenation reactions range from simple aromatic substitutions to stereoselective C-H functionalizations on remote carbon centers and can initiate the formation of simple to complex ring structures. Dehalogenating enzymes, on the other hand, are best known for removing halogen atoms from man-made organohalogens, yet also function naturally, albeit rarely, in metabolic pathways. This review details the scope and mechanism of nature's halogenation and dehalogenation enzymatic strategies, highlights gaps in our understanding, and posits where new advances in the field might arise in the near future.

Exposure to methyl tert-butyl ether and benzene among service station attendants and operators.

PubMed Central

Hartle, R

1993-01-01

Concerns for atmospheric pollution from auto exhaust have led to the blending of "oxygenates" with motor fuels. The most common oxygenate, methyl tert-butyl ether (MTBE) is currently required within several metropolitan areas (Denver and Phoenix) in the range of 12% of the motor fuel. Amendments to the Clean Air Act may expand this requirement to as many as 44 other areas of the United States in the near future. In consideration of the magnitude of potential uncontrolled exposures from its extensive use and a related concern involving the potential influence of MTBE blending on exposures to other constituents of gasoline (particularly benzene), an evaluation of exposures among service station attendants and operators was undertaken at the request, and in cooperation with, the American Petroleum Institute during the latter part of 1990. For application of the survey results to a broad audience, three categories or types of service stations were identified with regard to MTBE use and exposure potential: a) service stations that do not use MTBE or use it only as an octane enhancer, b) service stations with seasonal requirements to use 12-15% MTBE (the Denver, Colorado, and Phoenix, Arizona, metropolitan areas), and c) service stations equipped with stage II (active) vapor recovery systems (several coastal areas, most notably Southern California). At the two sampled service stations that use only minimal amounts of MTBE (less than 1%), only 1 of 32 personal breathing zone (PBZ) samples from attendants was above the analytical limit of detection, reported at 0.16 ppm. The geometric mean concentration of benzene among this same population (n = 32) was 0.04 ppm.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8020445

Exposure to methyl tert-butyl ether and benzene among service station attendants and operators.

PubMed

Hartle, R

1993-12-01

Concerns for atmospheric pollution from auto exhaust have led to the blending of "oxygenates" with motor fuels. The most common oxygenate, methyl tert-butyl ether (MTBE) is currently required within several metropolitan areas (Denver and Phoenix) in the range of 12% of the motor fuel. Amendments to the Clean Air Act may expand this requirement to as many as 44 other areas of the United States in the near future. In consideration of the magnitude of potential uncontrolled exposures from its extensive use and a related concern involving the potential influence of MTBE blending on exposures to other constituents of gasoline (particularly benzene), an evaluation of exposures among service station attendants and operators was undertaken at the request, and in cooperation with, the American Petroleum Institute during the latter part of 1990. For application of the survey results to a broad audience, three categories or types of service stations were identified with regard to MTBE use and exposure potential: a) service stations that do not use MTBE or use it only as an octane enhancer, b) service stations with seasonal requirements to use 12-15% MTBE (the Denver, Colorado, and Phoenix, Arizona, metropolitan areas), and c) service stations equipped with stage II (active) vapor recovery systems (several coastal areas, most notably Southern California). At the two sampled service stations that use only minimal amounts of MTBE (less than 1%), only 1 of 32 personal breathing zone (PBZ) samples from attendants was above the analytical limit of detection, reported at 0.16 ppm. The geometric mean concentration of benzene among this same population (n = 32) was 0.04 ppm.(ABSTRACT TRUNCATED AT 250 WORDS)

Synthesis and in vivo anticonvulsant activity of 2-methyl-2-[3-(5-piperazin-1-yl-[1,3,4]oxadiazol-2-yl)-phenyl]-propionitrile derivatives.

PubMed

Harish, Kikkeri P; Mohana, Kikkeri N; Mallesha, Lingappa; Veeresh, Bantal

2014-04-01

A series of new 2-methyl-2-[3-(5-piperazin-1-yl-[1,3,4]oxadiazol-2-yl)-phenyl]-propionitrile derivatives 8a-o, 9a-c, 10a-d, and 11a-d were synthesized to meet the structural requirements essential for anticonvulsant property. The structures of all the synthesized compounds were confirmed by means of (1)H NMR, (13)C NMR, and mass spectral studies. The purity of the novel compounds was confirmed by elemental analyses. All the compounds were screened for their anticonvulsant activity against maximal electroshock (MES) seizure method and their neurotoxic effects were determined by rotorod test. Compounds 8d, 8e, and 8f were found to be the most potent of this series. The same compounds showed no neurotoxicity at the maximum dose administered (100 mg/kg). The efforts were also made to establish the structure-activity relationships among the synthesized compounds. The pharmacophore model was used to validate the anticonvulsant activity of the synthesized molecules. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Traceable atomic force microscopy of high-quality solvent-free crystals of [6,6]-phenyl-C{sub 61}-butyric acid methyl ester

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lazzerini, Giovanni Mattia; Yacoot, Andrew; Paternò, Giuseppe Maria

2016-02-01

We report high-resolution, traceable atomic force microscopy measurements of high-quality, solvent-free single crystals of [6,6]-phenyl-C61-butyric acid methyl ester (PCBM). These were grown by drop-casting PCBM solutions onto the spectrosil substrates and by removing the residual solvent in a vacuum. A home-built atomic force microscope featuring a plane mirror differential optical interferometer, fiber-fed from a frequency-stabilized laser (emitting at 632.8 nm), was used to measure the crystals' height. The optical interferometer together with the stabilized laser provides traceability (via the laser wavelength) of the vertical measurements made with the atomic force microscope. We find that the crystals can conform to the surfacemore » topography, thanks to their height being significantly smaller compared to their lateral dimensions (namely, heights between about 50 nm and 140 nm, for the crystals analysed, vs. several tens of microns lateral dimensions). The vast majority of the crystals are flat, but an isolated, non-flat crystal provides insights into the growth mechanism and allows identification of “molecular terraces” whose height corresponds to one of the lattice constants of the single PCBM crystal (1.4 nm) as measured with X-ray diffraction.« less

Cytotoxic halogenated monoterpenes from Plocamium cartilagineum.

PubMed

Sabry, Omar M M; Goeger, Douglas E; Valeriote, Frederick A; Gerwick, William H

2017-02-01

As a result of our efforts to identify bioactive agents from marine algae, we have isolated and identified one new halogenated monoterpene 1 [(-)-(5E,7Z)-348-trichloro-7-dichloromethyl-3-methyl-157-octatriene] in addition to three known compounds (2, 3 and 4) from the red alga Plocamium cartilagineum collected by hand from the eastern coast of South Africa. Compound 1 was found to be active as a cytotoxic agent in human lung cancer (NCI-H460) and mouse neuro-2a cell lines (IC 50 4 μg/mL). Two of these compounds (3 and 4) were found to have cytotoxic activity in other cell line assays, especially against human leukaemia and human colon cancers (IC 50 1.3 μg/mL). None of these metabolites were active as sodium channel blockers or activators. All structures were determined by spectroscopic methods (UV, IR, LRMS, HRMS, 1D NMR and 2D NMR). 1D and 2D NOE experiments were carried out on these compounds to confirm the geometry of the double bonds.

N,N,N′,N′,N′′-Penta­methyl-N′′-[3-(1,3,3-trimethyl­ureido)prop­yl]guanidinium tetra­phenyl­borate

PubMed Central

Tiritiris, Ioannis; Kantlehner, Willi

2012-01-01

In the crystal structure of the title molecular salt, C13H30N5O+·C24H20B−, discrete guanidinium cations and tetra­phenyl­borate anions are present. The C—N bond lengths in the CN3 unit are 1.3427 (12), 1.3445 (12) and 1.3453 (13) Å, indicating double-bond character. The central C atom is surrounded in a nearly ideal trigonal-planar geometry by three N atoms and the positive charge is delocalized on the CN3 plane. The bonds between the N atoms and the terminal C-methyl groups all have values close to a typical single bond [1.4595 (15)–1.4688 (12) Å]. In the crystal, cations are connected by C—H⋯O contacts generating a chain along the c axis. PMID:22798881

Halogens in chondritic meteorites and terrestrial accretion

NASA Astrophysics Data System (ADS)

Clay, Patricia L.; Burgess, Ray; Busemann, Henner; Ruzié-Hamilton, Lorraine; Joachim, Bastian; Day, James M. D.; Ballentine, Christopher J.

2017-11-01

Volatile element delivery and retention played a fundamental part in Earth’s formation and subsequent chemical differentiation. The heavy halogens—chlorine (Cl), bromine (Br) and iodine (I)—are key tracers of accretionary processes owing to their high volatility and incompatibility, but have low abundances in most geological and planetary materials. However, noble gas proxy isotopes produced during neutron irradiation provide a high-sensitivity tool for the determination of heavy halogen abundances. Using such isotopes, here we show that Cl, Br and I abundances in carbonaceous, enstatite, Rumuruti and primitive ordinary chondrites are about 6 times, 9 times and 15-37 times lower, respectively, than previously reported and usually accepted estimates. This is independent of the oxidation state or petrological type of the chondrites. The ratios Br/Cl and I/Cl in all studied chondrites show a limited range, indistinguishable from bulk silicate Earth estimates. Our results demonstrate that the halogen depletion of bulk silicate Earth relative to primitive meteorites is consistent with the depletion of lithophile elements of similar volatility. These results for carbonaceous chondrites reveal that late accretion, constrained to a maximum of 0.5 ± 0.2 per cent of Earth’s silicate mass, cannot solely account for present-day terrestrial halogen inventories. It is estimated that 80-90 per cent of heavy halogens are concentrated in Earth’s surface reservoirs and have not undergone the extreme early loss observed in atmosphere-forming elements. Therefore, in addition to late-stage terrestrial accretion of halogens and mantle degassing, which has removed less than half of Earth’s dissolved mantle gases, the efficient extraction of halogen-rich fluids from the solid Earth during the earliest stages of terrestrial differentiation is also required to explain the presence of these heavy halogens at the surface. The hydropilic nature of halogens, whereby they track

Effect of Methyl Substitution on the N-H···O Interaction in Complexes of Pyrrole with Water, Methanol, and Dimethyl Ether: Matrix Isolation Infrared Spectroscopy and ab Initio Computational Studies.

PubMed

Sarkar, Shubhra; Ramanathan, N; Sundararajan, K

2018-03-08

Hydrogen-bonded interactions of pyrrole with water and methanol have been studied using matrix isolation infrared spectroscopy and compared with the calculation performed on dimethyl ether. Computations carried out at MP2/aug-cc-pVDZ level of theory yielded two minima for the pyrrole-water and pyrrole-methanol complexes. The global and local minima correspond to the N-H···O and O-H···π complexes, respectively, where the N-H group of pyrrole interacts with oxygen of water/methanol and O-H of water and methanol interacts with the π cloud of pyrrole. Computations performed on the pyrrole-dimethyl ether gave only N-H···O type complex. From the experimental vibrational wavenumber shifts in the N-H stretching and N-H bending modes of pyrrole, as well as in the O-H stretching modes of water and methanol, the 1:1 N-H···O complexes were discerned. The strength of the N-H···O hydrogen bond and the corresponding shift in the N-H stretching vibrational wavenumbers increases in the order pyrrole-water < pyrrole-methanol < pyrrole-dimethyl ether, where a proton is successively replaced by a methyl group. Apart from the 1:1 complexes, higher clusters of 2:1 and 1:2 pyrrole-water and pyrrole-methanol complexes were also generated in N 2 matrix. Atoms in molecules and natural bond orbital analyses were carried out at the MP2/aug-cc-pVDZ level to understand the nature of interaction in the 1:1 pyrrole-water, pyrrole-methanol and pyrrole-dimethyl ether complexes.

The fungal phytotoxin alternariol 9-methyl ether and some of its synthetic analogues inhibit the photosynthetic electron transport chain.

PubMed

Demuner, Antonio Jacinto; Barbosa, Luiz Cláudio Almeida; Miranda, Ana Cristina Mendes; Geraldo, Guilherme Carvalho; da Silva, Cleiton Moreira; Giberti, Samuele; Bertazzini, Michele; Forlani, Giuseppe

2013-12-27

Alternariol and monomethylalternariol are natural phytotoxins produced by some fungal strains, such as Nimbya and Alternaria. These substances confer virulence to phytopathogens, yet no information is available concerning their mode of action. Here we show that in the micromolar range alternariol 9-methyl ether is able to inhibit the electron transport chain (IC50 = 29.1 ± 6.5 μM) in isolated spinach chloroplasts. Since its effectiveness is limited by poor solubility in water, several alternariol analogues were synthesized using different aromatic aldehydes. The synthesized 6H-benzo[c]cromen-6-ones, 5H-chromene[4,3-b]pyridin-5-one, and 5H-chromene[4,3-c]pyridin-5-one also showed inhibitory properties, and three 6H-benzo[c]cromen-6-ones were more effective (IC50 = 12.8-22.8 μM) than the lead compound. Their addition to the culture medium of a cyanobacterial model strain was found to inhibit algal growth, with a relative effectiveness that was consistent with their activity in vitro. In contrast, the growth of a nonphotosynthetic plant cell culture was poorly affected. These compounds may represent a novel lead for the development of new active principles targeting photosynthesis.

Incombustible resin composition

NASA Technical Reports Server (NTRS)

Akima, T.

1982-01-01

Incombustible resin compositions composed of aromatic compounds were obtained through (1) combustion polymer material and (2) bisphenol A or halogenated bisphenol A and bisphenol A diglycidl ether or halogenated bisphenol A diglycidyl ether. The aromatic compound is an adduct of bifunctional phenols and bifunctional epoxy resins.

Process for removal of hydrogen halides or halogens from incinerator gas

DOEpatents

Huang, Hann S.; Sather, Norman F.

1988-01-01

A process for reducing the amount of halogens and halogen acids in high temperature combustion gases and through their removal, the formation of halogenated organics at lower temperatures, with the reduction being carried out electrochemically by contacting the combustion gas with the negative electrode of an electrochemical cell and with the halogen and/or halogen acid being recovered at the positive electrode.

Process for removal of hydrogen halides or halogens from incinerator gas

DOEpatents

Huang, H.S.; Sather, N.F.

1987-08-21

A process for reducing the amount of halogens and halogen acids in high temperature combustion gas and through their removal, the formation of halogenated organics at lower temperatures, with the reduction being carried out electrochemically by contacting the combustion gas with the negative electrode of an electrochemical cell and with the halogen and/or halogen acid being recovered at the positive electrode.

Inhibition of Zero Drift in Perovskite-Based Photodetector Devices via [6,6]-Phenyl-C61-butyric Acid Methyl Ester Doping.

PubMed

Liu, Yintao; Jia, Renxu; Wang, Yucheng; Hu, Ziyang; Zhang, Yuming; Pang, Tiqiang; Zhu, Yuejin; Luan, Suzhen

2017-05-10

Zero drift can severely deteriorate the stability of the light-dark current ratio, detectivity, and responsivity of photodetectors. In this paper, the effects of a [6,6]-phenyl-C61-butyric acid methyl ester (PCBM)-doped perovskite-based photodetector device on the inhibition of zero drift under dark state are discussed. Two kinds of photodetectors (Au/CH 3 NH 3 PbI x Cl 3-x /Au and Au/CH 3 NH 3 PbI x Cl 3-x :PCBM/Au) were prepared, and the materials and photodetector devices were measured by scanning electron microscopy, X-ray diffraction, photoluminescence, ultraviolet absorption spectra, and current-voltage and current-time measurements. It was found that similar merit parameters, including light-dark current ratio (∼10 2 ), detectivity (∼10 11 Jones), and responsivity were obtained for these two kinds of photodetectors. However, the drift of Au/CH 3 NH 3 PbI x Cl 3-x :PCBM/Au devices is negligible, while a drift of ∼0.2 V exists in Au/CH 3 NH 3 PbI x Cl 3-x /Au devices. A new model is proposed based on the hindering theory of ion (vacancy) migration, and it is believed that the dopant PCBM can hinder the ion (vacancy) migration of perovskite materials to suppress the phenomenon of zero drift in perovskite-based photodetectors.

Crystal structure of N′′-benzyl-N′′-[3-(benzyl­dimethyl­aza­nium­yl)prop­yl]-N,N,N′,N′-tetra­methyl­guanidinium bis­(tetra­phenyl­borate)

PubMed Central

Tiritiris, Ioannis; Kantlehner, Willi

2015-01-01

In the crystal structure of the title salt, C24H38N4 2+·2C24H20B−, the C—N bond lengths in the central CN3 unit of the guanidinium ion are 1.3364 (13), 1.3407 (13) and 1.3539 (13) Å, indicating partial double-bond character. The central C atom is bonded to the three N atoms in a nearly ideal trigonal–planar geometry and the positive charge is delocalized in the CN3 plane. The bonds between the N atoms and the terminal methyl groups of the guanidinium moiety and the four C—N bonds to the central N atom of the (benzyl­dimethyl­aza­nium­yl)propyl group have single-bond character. In the crystal, C—H⋯π inter­actions between the guanidin­ium H atoms and the phenyl C atoms of the tetra­phenyl­borate ions are present, leading to the formation of a two-dimensional supra­molecular pattern parallel to the ac plane. PMID:26870511

Legacy and alternative halogenated flame retardants in human milk in Europe: Implications for children's health.

PubMed

Čechová, Eliška; Vojta, Šimon; Kukučka, Petr; Kočan, Anton; Trnovec, Tomáš; Murínová, Ľubica Palkovičová; de Cock, Marijke; van de Bor, Margot; Askevold, Joakim; Eggesbø, Merete; Scheringer, Martin

2017-11-01

In this study, 10 polybrominated diphenyl ethers (PBDEs) and 19 alternative halogenated flame retardants (AFRs) were determined in >450 human milk samples across three European countries, representing northern, western and eastern Europe. This study provides first insights into the occurrence of selected AFRs in mother milk samples and compares them among three European countries. Sums of median concentrations of the most frequently detected PBDEs were 2.16, 0.88 and 0.45ngg -1 lipid weight (lw) in Norway, the Netherlands and Slovakia, respectively. The sum of the concentrations of AFRs ranged from 0.14 to 0.25ngg -1 lw in all countries, which was 2 to 15 times less compared to Σ 7 PBDEs. The Penta-BDE replacement, bis(2-ethylhexyl) tetrabromophthalate, BEH-TEBP, was present at the greatest concentrations of any of the AFRs and in some samples exceeded concentrations of BDE 47 and BDE 153. Four AFRs including bromobenzenes (hexabromobenzene, pentabromobenzene, pentabromotoluene) and another Penta-BDE replacement (2-ethylhexyl-2,3,4,5-tetrabromobenzoate, EH-TBB) were detected in >42% of all human milk samples. Because of the potential developmental neurotoxicity of the halogenated flame retardants, infant dietary intakes via breastfeeding were estimated; in four cases the intakes of BDE 47 exceeded the reference dose indicating that the present concentrations may pose a risk for children. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effect of degree of sulfonation and casting solvent on sulfonated poly(ether ether ketone) membrane for vanadium redox flow battery

NASA Astrophysics Data System (ADS)

Xi, Jingyu; Li, Zhaohua; Yu, Lihong; Yin, Bibo; Wang, Lei; Liu, Le; Qiu, Xinping; Chen, Liquan

2015-07-01

The properties of sulfonated poly(ether ether ketone) (SPEEK) membranes with various degree of sulfonation (DS) and casting solvent are investigated for vanadium redox flow battery (VRFB). The optimum DS of SPEEK membrane is firstly confirmed by various characterizations such as physicochemical properties, ion selectivity, and VRFB single-cell performance. Subsequently the optimum casting solvent is selected for the optimum DS SPEEK membrane within N,N‧-dimethylformamide (DMF), N,N‧-dimethylacetamide (DMAc), N-methyl-2-pyrrolidone (NMP), and dimethylsulfoxide (DMSO). The different performance of SPEEK membranes prepared with various casting solvents can be attributed to the different interaction between solvent and -SO3H group of SPEEK. In the VRFB single-cell test, the optimum SPEEK membrane with DS of 67% and casting solvent of DMF (S67-DMF membrane) exhibits higher VRFB efficiencies and better cycle-life performance at 80 mA cm-2. The investigation of various DS and casting solvent will be effective guidance on the selection and modification of SPEEK membrane towards VRFB application.

Role of alpha-synuclein in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced parkinsonism in mice.

PubMed

Schlüter, O M; Fornai, F; Alessandrí, M G; Takamori, S; Geppert, M; Jahn, R; Südhof, T C

2003-01-01

In humans, mutations in the alpha-synuclein gene or exposure to the neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) produce Parkinson's disease with loss of dopaminergic neurons and depletion of nigrostriatal dopamine. alpha-Synuclein is a vertebrate-specific component of presynaptic nerve terminals that may function in modulating synaptic transmission. To test whether MPTP toxicity involves alpha-synuclein, we generated alpha-synuclein-deficient mice by homologous recombination, and analyzed the effect of deleting alpha-synuclein on MPTP toxicity using these knockout mice. In addition, we examined commercially available mice that contain a spontaneous loss of the alpha-synuclein gene. As described previously, deletion of alpha-synuclein had no significant effects on brain structure or composition. In particular, the levels of synaptic proteins were not altered, and the concentrations of dopamine, dopamine metabolites, and dopaminergic proteins were unchanged. Upon acute MPTP challenge, alpha-synuclein knockout mice were partly protected from chronic depletion of nigrostriatal dopamine when compared with littermates of the same genetic background, whereas mice carrying the spontaneous deletion of the alpha-synuclein gene exhibited no protection. Furthermore, alpha-synuclein knockout mice but not the mice with the alpha-synuclein gene deletion were slightly more sensitive to methamphetamine than littermate control mice. These results demonstrate that alpha-synuclein is not obligatorily coupled to MPTP sensitivity, but can influence MPTP toxicity on some genetic backgrounds, and illustrate the need for extensive controls in studies aimed at describing the effects of mouse knockouts on MPTP sensitivity.

Binding-Induced Fluorescence of Serotonin Transporter Ligands: A Spectroscopic and Structural Study of 4-(4-(Dimethylamino)phenyl)-1-methylpyridinium (APP+) and APP+ Analogues

PubMed Central

2014-01-01

The binding-induced fluorescence of 4-(4-(dimethylamino)-phenyl)-1-methylpyridinium (APP+) and two new serotonin transporter (SERT)-binding fluorescent analogues, 1-butyl-4-[4-(1-dimethylamino)phenyl]-pyridinium bromide (BPP+) and 1-methyl-4-[4-(1-piperidinyl)phenyl]-pyridinium (PPP+), has been investigated. Optical spectroscopy reveals that these probes are highly sensitive to their chemical microenvironment, responding to variations in polarity with changes in transition energies and responding to changes in viscosity or rotational freedom with emission enhancements. Molecular docking calculations reveal that the probes are able to access the nonpolar and conformationally restrictive binding pocket of SERT. As a result, the probes exhibit previously not identified binding-induced turn-on emission that is spectroscopically distinct from dyes that have accumulated intracellularly. Thus, binding and transport dynamics of SERT ligands can be resolved both spatially and spectroscopically. PMID:24460204

Optically active antifungal azoles. XII. Synthesis and antifungal activity of the water-soluble prodrugs of 1-[(1R,2R)-2-(2,4-difluorophenyl)-2-hydroxy-1-methyl-3-(1H-1,2,4-triazol-1-yl)propyl]-3-[4-(1H-1-tetrazolyl)phenyl]-2-imidazolidinone.

PubMed

Ichikawa, T; Kitazaki, T; Matsushita, Y; Yamada, M; Hayashi, R; Yamaguchi, M; Kiyota, Y; Okonogi, K; Itoh, K

2001-09-01

1-[(1R,2R)-2-(2,4-Difluorophenyl)-2-hydroxy-1-methyl-3-(1H-1,2,4-triazol-1-yl)propyl]-3-[4-(1H-1-tetrazolyl)phenyl]-2-imidazolidinone (1: TAK-456) was selected as a candidate for clinical trials, but since its water-solubility was insufficient for an injectable formulation, the quaternary triazolium salts 2 were designed as water-soluble prodrugs. Among the prodrugs prepared, 4-acetoxymethyl-1-[(2R,3R)-2-(2,4-difluorophenyl)-2-hydroxy-3-[2-oxo-3-[4-(1H-1-terazolyl)phenyl]-1-imidazolidinyl]butyl]-1H-1,2,4-triazolium chloride (2a: TAK-457) was selected as an injectable candidate for clinical trials based on the results of evaluations on solubility, stability, hemolytic effect and in vivo antifungal activities.

(But­oxy­methyl­idene)di­methyl­aza­nium tetra­phenyl­borate aceto­nitrile monosolvate

PubMed Central

Tiritiris, Ioannis; Saur, Stefan; Kantlehner, Willi

2014-01-01

In the title solvated salt, C7H16NO+·C24H20B−·C2H3N, the C—N bond lengths in the cation are 1.2831 (19), 1.467 (2) and 1.465 (2) Å, indicating double- and single-bond character, respectively. The C—O bond length of 1.2950 (18) Å shows a double-bond character, pointing towards charge delocalization within the NCO plane of the iminium ion. The two C atoms of the n-butyl group are disordered over the two sites, with refined occupancy ratios of 0.890 (5):0.110 (5) and 0.888 (4):0.112 (4). In the crystal, C—H⋯π inter­actions occur between the methine H atom, H atoms of the –N(CH3)2 and –CH2 groups of the cation, and two of the phenyl rings of the tetra­phenyl­borate anion. The latter inter­action forms an aromatic pocket in which the cation is embedded. Thus, a two-dimensional pattern is created in the ac plane. PMID:24826158

Prolonged Hypocalcemic Effect by Pulmonary Delivery of Calcitonin Loaded Poly(Methyl Vinyl Ether Maleic Acid) Bioadhesive Nanoparticles

PubMed Central

Varshosaz, J.; Minaiyan, M.; Forghanian, M.

2014-01-01

The purpose of the present study was to design a pulmonary controlled release system of salmon calcitonin (sCT). Therefore, poly(methyl vinyl ether maleic acid) [P(MVEMA)] nanoparticles were prepared by ionic cross-linking method using Fe2+ and Zn2+ ions. Physicochemical properties of nanoparticles were studied in vitro. The stability of sCT in the optimized nanoparticles was studied by electrophoretic gel method. Plasma calcium levels until 48 h were determined in rats as pulmonary-free sCT solution or nanoparticles (25 μg·kg−1), iv solution of sCT (5 μg·kg−1), and pulmonary blank nanoparticles. The drug remained stable during fabrication and tests on nanoparticles. The optimized nanoparticles showed proper physicochemical properties. Normalized reduction of plasma calcium levels was at least 2.76 times higher in pulmonary sCT nanoparticles compared to free solution. The duration of hypocalcemic effect of pulmonary sCT nanoparticles was 24 h, while it was just 1 h for the iv solution. There was not any significant difference between normalized blood calcium levels reduction in pulmonary drug solution and iv injection. Pharmacological activity of nanoparticles after pulmonary delivery was 65% of the iv route. Pulmonary delivery of P(MVEMA) nanoparticles of sCT enhanced and prolonged the hypocalcemic effect of the drug significantly. PMID:24701588

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

NASA Astrophysics Data System (ADS)

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

2016-08-01

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

5-Chloro-5''-[4-(di-methyl-amino)-benzyl-idene]-4'-[4-(di-methyl-amino)-phen-yl]-1',1''-di-methyl-dispiro-[indoline-3,2'-pyrrolidine-3',3''-piperidine]-2,4''-dione.

PubMed

Farag, I S Ahmed; Girgis, Adel S; Ramadan, A A; Moustafa, A M; Tiekink, Edward R T

2014-01-01

The title compound, C34H38ClN5O2, has spiro links connecting the pyrrolidine ring and indole residue, as well as the piperidine and pyrrolidine rings. A half-chair conformation is found for the piperidine ring with the C atom connected to the spiro-C atom lying 0.738 (4) Å out of the plane of the remaining five atoms (r.m.s. deviation = 0.0407 Å). The methyl-ene C atom is the flap in the envelope conformation for the pyrrolidine ring. In the crystal, supra-molecular chains are sustained by alternating eight-membered {⋯HNCO}2 and 14-membered {⋯HC5O}2 synthons. Chains are connected into a three-dimensional network by (pyrrolidine-bound phenyl-meth-yl)C-H⋯π(pyrrolidine-bound phen-yl) edge-to-face inter-actions.

Thermal and Optical Properties of New Poly(amide-imide)/Nanocomposite Reinforced by Layer Silicate Containing Diphenyl Ether Moieties

NASA Astrophysics Data System (ADS)

Faghihi, Khalil; Faramarzi, Ellahe; Shabanian, Meisam

2011-04-01

New poly(amide-imide)-montmorillonite reinforced nanocomposites containing Bis(4-N-trimellitylimido) diphenyl ether moiety in the main chain were synthesized by a convenient solution intercalation technique. Poly(amide-imide) (PAI) 4 was synthesized by the direct polycondensation reaction of Bis(4-N-trimellitylimido) diphenyl ether 3 with 4,4'-diamino diphenyl ether 2 in the presence of triphenyl phosphite (TPP), CaCl2, pyridine and N-methyl-2-pyrrolidone (NMP). Morphology and structure of the resulting PAI-nanocomposite films 4a and 4b with 10 and 20 mass% silicate particles respectively, were characterized by FT-IR spectroscopy, X-ray diffraction (XRD) and scanning electron microscopy (SEM). The properties of nanocomposites films were investigated by using Uv-vis spectroscopy, thermogravimetric analysis (TGA) and water uptake measurements.

Process for conversion of lignin to reformulated, partially oxygenated gasoline

DOEpatents

Shabtai, Joseph S.; Zmierczak, Wlodzimierz W.; Chornet, Esteban

2001-01-09

A high-yield process for converting lignin into reformulated, partially oxygenated gasoline compositions of high quality is provided. The process is a two-stage catalytic reaction process that produces a reformulated, partially oxygenated gasoline product with a controlled amount of aromatics. In the first stage of the process, a lignin feed material is subjected to a base-catalyzed depolymerization reaction, followed by a selective hydrocracking reaction which utilizes a superacid catalyst to produce a high oxygen-content depolymerized lignin product mainly composed of alkylated phenols, alkylated alkoxyphenols, and alkylbenzenes. In the second stage of the process, the depolymerized lignin product is subjected to an exhaustive etherification reaction, optionally followed by a partial ring hydrogenation reaction, to produce a reformulated, partially oxygenated/etherified gasoline product, which includes a mixture of substituted phenyl/methyl ethers, cycloalkyl methyl ethers, C.sub.7 -C.sub.10 alkylbenzenes, C.sub.6 -C.sub.10 branched and multibranched paraffins, and alkylated and polyalkylated cycloalkanes.

Interface-engineering additives of poly(oxyethylene tridecyl ether) for low-band gap polymer solar cells consisting of PCDTBT:PCBM₇₀ bulk-heterojunction layers.

PubMed

Huh, Yoon Ho; Park, Byoungchoo

2013-01-14

We herein report on the improved photovoltaic (PV) effects of using a polymer bulk-heterojunction (BHJ) layer that consists of a low-band gap electron donor polymer of poly(N-9'-heptadecanyl-2,7-carbazole-alt-5,5-(4',7'-di-2-thienyl-2',1',3'-benzothiadiazole)) (PCDTBT) and an acceptor of [6,6]-phenyl C₇₁ butyric acid methyl ester (PCBM₇₀), doped with an interface-engineering surfactant additive of poly(oxyethylene tridecyl ether) (PTE). The presence of an interface-engineering additive in the PV layer results in excellent performance; the addition of PTE to a PCDTBT:PCBM₇₀ system produces a power conversion efficiency (PCE) of 6.0%, which is much higher than that of a reference device without the additive (4.9%). We attribute this improvement to an increased charge carrier lifetime, which is likely to be the result of the presence of PTE molecules oriented at the interfaces between the BHJ PV layer and the anode and cathode, as well as at the interfaces between the phase-separated BHJ domains. Our results suggest that the incorporation of the PTE interface-engineering additive in the PCDTBT:PCBM₇₀ PV layer results in a functional composite system that shows considerable promise for use in efficient polymer BHJ PV cells.

Estimation of dark and active dielectric constants in the sub-THz frequency domain of an optically tunable organic semiconductor blend of poly(3-hexylthiophene) and phenyl-C61-butyric acid methyl ester

NASA Astrophysics Data System (ADS)

Andy, Andre S.; Kneller, James W. E.; Sushko, Oleksandr; Dubrovka, Rostyslav; Parini, Clive; Scott, Ken; Kreouzis, Theo; Donnan, Robert S.

2018-06-01

The dielectric properties of a 95% poly(3-hexylthiophene):5% phenyl-C61-butyric acid methyl ester blend are measured in the dark and under white light illumination by quasi-optical transmissometry and terahertz time-domain spectroscopy. The real part of the dielectric constant varies monotonically between 2.75 and 3.50, in agreement with the literature, and displays a reversible photoinduced drop of 0.05–0.55 at sub-THz. The imaginary part fluctuates between 0.1 and 1.5 in the dark and displays a reversible increase upon illumination of 0.10–0.52 at sub-THz. The corresponding charge carrier concentration under illumination (using transient and steady-state photoconduction) is 1014 to 1015 cm‑3.

Microbial toxicity of methyl tert-butyl ether (MTBE) determined with fluorescent and luminescent bioassays.

PubMed

Roslev, Peter; Lentz, Trine; Hesselsoe, Martin

2015-02-01

The inhibitory effects of the fuel additive methyl tert-butyl ether (MTBE) and potential degradation products tert-butanol (TBA) and formaldehyde was examined using mixed microbial biomass, and six strains of bioluminescent bacteria and yeast. The purpose was to assess microbial toxicity with quantitative bioluminescent and fluorescent endpoints, and to identify sensitive proxies suitable for monitoring MTBE contamination. Bioluminescent Aliivibrio fischeri DSM 7151 (formerly Vibrio fischeri) appeared highly sensitive to MTBE exposure, and was a superior test organisms compared to lux-tagged Escherichia coli DH5α, Pseudomonas fluorescens DF57-40E7 and Saccharomyces cerevisiae BLYR. EC10 and EC50 for acute MTBE toxicity in A. fischeri were 1.1 and 10.9 mg L(-1), respectively. Long term (24h) MTBE exposure resulted in EC10 values of 0.01 mg L(-1). TBA was significantly less toxic with EC10 and EC50 for acute and chronic toxicity >1000 mg L(-1). Inhibition of bioluminescence was generally a more sensitive endpoint for MTBE toxicity than measuring intracellular ATP levels and heterotrophic CO2 assimilation. A weak estrogenic response was detected for MTBE at concentrations ⩾ 3.7 g L(-1) using an estrogen inducible bioluminescent yeast strain (S. cerevisiae BLYES). Microbial hydrolytic enzyme activity in groundwater was affected by MTBE with EC10 values of 0.5-787 mg L(-1), and EC50 values of 59-3073 for alkaline phosphatase, arylsulfatase, beta-1,4-glucanase, N-acetyl-beta-d-glucosaminidase, and leucine-aminopeptidase. Microbial alkaline phosphatase and beta-1,4-glucanase activity were most sensitive to MTBE exposure with EC50 ⩽ 64.8 mg L(-1). The study suggests that bioassays with luminescent A. fischeri, and fluorescent assays targeting hydrolytic enzyme activity are good candidates for monitoring microbial MTBE toxicity in contaminated water. Copyright © 2014 Elsevier Ltd. All rights reserved.

Characterization of an O-Demethylase of Desulfitobacterium hafniense DCB-2

PubMed Central

Studenik, Sandra; Vogel, Michaela

2012-01-01

Besides acetogenic bacteria, only Desulfitobacterium has been described to utilize and cleave phenyl methyl ethers under anoxic conditions; however, no ether-cleaving O-demethylases from the latter organisms have been identified and investigated so far. In this study, genes of an operon encoding O-demethylase components of Desulfitobacterium hafniense strain DCB-2 were cloned and heterologously expressed in Escherichia coli. Methyltransferases I and II were characterized. Methyltransferase I mediated the ether cleavage and the transfer of the methyl group to the superreduced corrinoid of a corrinoid protein. Desulfitobacterium methyltransferase I had 66% identity (80% similarity) to that of the vanillate-demethylating methyltransferase I (OdmB) of Acetobacterium dehalogenans. The substrate spectrum was also similar to that of the latter enzyme; however, Desulfitobacterium methyltransferase I showed a higher level of activity for guaiacol and used methyl chloride as a substrate. Methyltransferase II catalyzed the transfer of the methyl group from the methylated corrinoid protein to tetrahydrofolate. It also showed a high identity (∼70%) to methyltransferases II of A. dehalogenans. The corrinoid protein was produced in E. coli as cofactor-free apoprotein that could be reconstituted with hydroxocobalamin or methylcobalamin to function in the methyltransferase I and II assays. Six COG3894 proteins, which were assumed to function as activating enzymes mediating the reduction of the corrinoid protein after an inadvertent oxidation of the corrinoid cofactor, were studied with respect to their abilities to reduce the recombinant reconstituted corrinoid protein. Of these six proteins, only one was found to catalyze the reduction of the corrinoid protein. PMID:22522902

Method and apparatus for low temperature destruction of halogenated hydrocarbons

DOEpatents

Reagen, William Kevin; Janikowski, Stuart Kevin

1999-01-01

A method and apparatus for decomposing halogenated hydrocarbons are provided. The halogenated hydrocarbon is mixed with solvating agents and maintained in a predetermined atmosphere and at a predetermined temperature. The mixture is contacted with recyclable reactive material for chemically reacting with the recyclable material to create dehalogenated hydrocarbons and halogenated inorganic compounds. A feature of the invention is that the process enables low temperature destruction of halogenated hydrocarbons.

Halogen Chemistry at North American Coastal Sites

NASA Astrophysics Data System (ADS)

Stutz, J.; Pikelnaya, O.; Laskin, A.; Sumner, A.; Jobson, B. T.; Finley, B.; Lawler, M.; Saltzman, E. S.; Pszenny, A. A.; Deegan, B.

2007-12-01

In recent years observational evidence has emerged that reactive halogen species (RHS), such as chlorine atoms, and bromine and iodine oxides, are present in coastal areas. Their chemistry can be significant as they catalytically destroy O3; oxidize hydrocarbons, dimethylsulfide, and S(IV); and modify NOx and HOx cycling. Despite their potential importance our observational database on RHS is still very limited. Most observations of RHS thus far have been made in clean areas and very few observations along the North American coast have been made. Here we will review our current understanding of RHS chemistry in both clean and polluted environments. Recent observations at coastal areas around the world will be discussed. We will also give an overview of an experiment performed by our group in Malibu, CA in October 2006 and present initial results. A suite of trace gases and environmental parameters, including halogen molecules, halogen oxides, Cl + VOC reaction products, aerosol composition, O3, NOx, CO, VOCs, meteorology, and radiation, were measured during a three week period. In addition, Cl + VOC reaction products were measured at two locations in urban Los Angeles. Clear evidence for the presence of various halogen species on the California coast was found. Observations during periods with relatively clean marine air and during times where our site was in the outflow of Los Angeles show the impact of pollution on coastal atmospheric chemistry. Our observations will be compared to earlier studies of halogen chemistry at coastal areas to further advance our understanding of halogen chemistry.

Design and synthesis of positional isomers of 5 and 6-bromo-1-[(phenyl)sulfonyl]-2-[(4-nitrophenoxy)methyl]-1H-benzimidazoles as possible antimicrobial and antitubercular agents.

PubMed

Ranjith, P Karuvalam; Rajeesh, P; Haridas, Karickal R; Susanta, Nayak K; Row, Tayur N Guru; Rishikesan, R; Kumari, N Suchetha

2013-09-15

In this Letter, we report the structure-activity relationship (SAR) studies on series of positional isomers of 5(6)-bromo-1-[(phenyl)sulfonyl]-2-[(4-nitrophenoxy)methyl]-1H-benzimidazoles derivatives 7(a-j) and 8(a-j) synthesized in good yields and characterized by (1)H NMR, (13)C NMR and mass spectral analyses. The crystal structure of 7a was evidenced by X-ray diffraction study. The newly synthesized compounds were evaluated for their in vitro antibacterial activity against Staphylococcus aureus, (Gram-positive), Escherichia coli and Klebsiella pneumoniae (Gram-negative), antifungal activity against Candida albicans, Aspergillus flavus and Rhizopus sp. and antitubercular activity against Mycobacterium tuberculosis H37Rv, Mycobacterium smegmatis, Mycobacterium fortuitum and MDR-TB strains. The synthesized compounds displayed interesting antimicrobial activity. The compounds 7b, 7e and 7h displayed significant activity against Mycobacterium tuberculosis H37Rv strain. Copyright © 2013 Elsevier Ltd. All rights reserved.

Crystal structure of bis­(N-methyl-N-phenyl­amino)­tris­ulfane

PubMed Central

Barany, George; Henley, Matthew J.; Polski, Lauren A.; Schroll, Alayne L.; Young, Victor G.

2015-01-01

The title compound, C14H16N2S3, crystallized with two independent mol­ecules [(1 a) and (1 b)] in the asymmetric unit. Both mol­ecules display a pseudo-trans conformation. The two consecutive S—S bond lengths of the tris­ulfane unit of mol­ecule (1 a) are 2.06 (3) and 2.08 (3) Å, and 2.08 (3) and 2.07 (2) Å for mol­ecule (1 b). Torsion angles about each of the two S—S bonds are 86.6 (2) and 87.0 (2)° for (1 a), and −84.6 (2) and −85.9 (2)° for (1 b). The core atoms, viz. the N—S—S—S—N moiety, of the two mol­ecules superimpose well if one is inverted on the other, but the phenyl groups do not. Thus, the two units are essentially conformational enanti­omers. In mol­ecule (1 a), the two phenyl rings are inclined to one another by 86.7 (3)°, and in mol­ecule (1 b), by 81.1 (3)°. In the crystal, mol­ecules are linked via C—H⋯π inter­actions, forming sheets lying parallel to (010). PMID:26279880

A new class of halogen bonds that avoids the σ-hole

NASA Astrophysics Data System (ADS)

Zhang, Yu; Ma, Ning; Wang, Weizhou

2012-04-01

A new class of halogen bonds of the type X = Hal⋯Y has been investigated by using the density functional theory calculations. The strength of this new class of halogen bonds is in the range of 90-120 kcal/mol, which is greatly larger than that of the conventional halogen bond of the type X-Hal⋯Y. The geometry of this new class of halogen bonds is not determined by the halogen's positive σ-hole. Natural bond orbital analysis shows it is the n → π∗ interaction that determines the geometry of this new class of halogen bonds. Experimental results are in good agreement with the theoretical predictions.

Self-healing pH-sensitive poly[(methyl vinyl ether)-alt-(maleic acid)]-based supramolecular hydrogels formed by inclusion complexation between cyclodextrin and adamantane.

PubMed

Ma, Xiaoe; Zhou, Naizhen; Zhang, Tianzhu; Hu, Wanjun; Gu, Ning

2017-04-01

Self-healing materials are of interest for drug delivery, cell and gene therapy, tissue engineering, and other biomedical applications. In this work, on the base of biocompatible polymer poly(methyl vinyl ether-alt-maleic acid) (P(MVE-alt-MA)), host polymer β-cyclodextrin-grafted P(MVE-alt-MA) (P(MVE-alt-MA)-g-β-CD) and guest polymer adamantane-grafted P(MVE-alt-MA) (P(MVE-alt-MA)-g-Ad) were first prepared. Then through taking advantage of the traditional host-guest interaction of β-cyclodextrin and adamantane, a novel self-healing pH-sensitive physical P(MVE-alt-MA)-g-β-CD/P(MVE-alt-MA)-g-Ad supramolecular hydrogels were obtained after simply mixing the aqueous solution of host polymer and guest polymer. This kind of supramolecular hydrogels not only possess pH-sensitivity, but also possess the ability to repair themselves after being damaged. Copyright © 2016 Elsevier B.V. All rights reserved.

Inhibition of cholinesterase activity and amyloid aggregation by berberine-phenyl-benzoheterocyclic and tacrine-phenyl-benzoheterocyclic hybrids.

PubMed

Huang, Ling; Su, Tao; Shan, Wenjun; Luo, Zonghua; Sun, Yang; He, Feng; Li, Xingshu

2012-05-01

A series of berberine-phenyl-benzoheterocyclic (26-29) and tacrine-phenyl-benzoheterocyclic hybrids (44-46) were synthesised and evaluated as multifunctional anti-Alzheimer's disease agents. Compound 44b, tacrine linked with phenyl-benzothiazole by 3-carbon spacers, was the most potent AChE inhibitor with an IC(50) value of 0.017 μM. This compound demonstrated similar Aβ aggregation inhibitory activity with cucurmin (51.8% vs 52.1% at 20 μM, respectively), indicating that this hybrid is an excellent multifunctional drug candidate for AD. Copyright © 2012 Elsevier Ltd. All rights reserved.

Halogen-Mediated Conversion of Hydrocarbons to Commodities.

PubMed

Lin, Ronghe; Amrute, Amol P; Pérez-Ramírez, Javier

2017-03-08

Halogen chemistry plays a central role in the industrial manufacture of various important chemicals, pharmaceuticals, and polymers. It involves the reaction of halogens or halides with hydrocarbons, leading to intermediate compounds which are readily converted to valuable commodities. These transformations, predominantly mediated by heterogeneous catalysts, have long been successfully applied in the production of polymers. Recent discoveries of abundant conventional and unconventional natural gas reserves have revitalized strong interest in these processes as the most cost-effective gas-to-liquid technologies. This review provides an in-depth analysis of the fundamental understanding and applied relevance of halogen chemistry in polymer industries (polyvinyl chloride, polyurethanes, and polycarbonates) and in the activation of light hydrocarbons. The reactions of particular interest include halogenation and oxyhalogenation of alkanes and alkenes, dehydrogenation of alkanes, conversion of alkyl halides, and oxidation of hydrogen halides, with emphasis on the catalyst, reactor, and process design. Perspectives on the challenges and directions for future development in this exciting field are provided.

40 CFR 721.285 - Acetamide, N-[4-(pentyloxy)phenyl]-, acetamide, N-[2-nitro-4-(pentyloxy)phenyl]-, and acetamide...

Code of Federal Regulations, 2010 CFR

2010-07-01

... § 721.90 (a)(4), (b)(4), and (c)(4) (where N = 90 ppb for PMNs P-92-31 and P-92-32, and N = 30 ppb for P... reporting. (1) The chemical substances identified as acetamide, N-[4-(pentyloxy)phenyl]- (PMN P-92-31), acetamide, N-[2-nitro-4-(pentyloxy)phenyl]- (PMN P-92-32), and acetamide, N-[2-amino-4-(pentyloxy)phenyl...

40 CFR 721.285 - Acetamide, N-[4-(pentyloxy)phenyl]-, acetamide, N-[2-nitro-4-(pentyloxy)phenyl]-, and acetamide...

Code of Federal Regulations, 2011 CFR

2011-07-01

... § 721.90 (a)(4), (b)(4), and (c)(4) (where N = 90 ppb for PMNs P-92-31 and P-92-32, and N = 30 ppb for P... reporting. (1) The chemical substances identified as acetamide, N-[4-(pentyloxy)phenyl]- (PMN P-92-31), acetamide, N-[2-nitro-4-(pentyloxy)phenyl]- (PMN P-92-32), and acetamide, N-[2-amino-4-(pentyloxy)phenyl...

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

PubMed Central

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

2017-01-01

Methyl tert-butyl ether (MTBE) has been used as a common gasoline additive worldwide since the late twentieth century, and it has become the most frequently detected groundwater pollutant in many countries. This study aimed to synthesize a novel microbial carrier to improve its adsorptive capacity for MTBE and biofilm formation, compared to the traditional granular activated carbon (GAC). A polypyrrole (PPy)-modified GAC composite (PPy/GAC) was synthesized, and characterized by Fourier transform infrared spectroscopy (FT-IR) and Brunauer-Emmett-Teller (BET) surface area analysis. The adsorption behaviors of MTBE were well described by the pseudo-second-order and Langmuir isotherm models. Furthermore, three biofilm reactors were established with PPy/GAC, PPy, and GAC as the carriers, respectively, and the degradation of MTBE under continuous flow was investigated. Compared to the biofilm reactors with PPy or GAC (which both broke after a period of operation), the PPy/GAC biofilm column produced stable effluents under variable treatment conditions with a long-term effluent MTBE concentration <20 μg/L. Pseudomonas aeruginosa and Acinetobacter pittii may be the predominant bacteria responsible for MTBE degradation in these biofilm reactors. PMID:28125030

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

USGS Publications Warehouse

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

2001-01-01

Microbial communities indigenous to a shallow groundwater system near Beaufort, SC, degraded milligram per liter concentrations of methyl tert-butyl ether (MTBE) under natural and artificial oxic conditions. Significant MTBE biodegradation was observed where anoxic, MTBE-contaminated groundwater discharged to a concrete-lined ditch. In the anoxic groundwater adjacent to the ditch, concentrations of MTBE were > 1 mg/L. Where groundwater discharge occurs, dissolved oxygen (DO) concentrations beneath the ditch exceeded 1.0 mg/L to a depth of 1.5 m, and MTBE concentrations decreased to <1 ??g/L prior to discharge. MTBE mass flux calculations indicate that 96% of MTBE mass loss occurs in the relatively small oxic zone prior to discharge. Samples of a natural microbial biofilm present in the oxic zone beneath the ditch completely degraded [U-14C]MTBE to [14C]CO2 in laboratory liquid culture studies, with no accumulation of intermediate compounds. Upgradient of the ditch in the anoxic, MTBE and BTEX-contaminated aquifer, addition of a soluble oxygen release compound resulted in oxic conditions and rapid MTBE biodegradation by indigenous microorganisms. In an observation well located closest to the oxygen addition area, DO concentrations increased from 0.4 to 12 mg/L in <60 days and MTBE concentrations decreased from 20 to 3 mg/L. In the same time period at a downgradient observation well, DO increased from <0.2 to 2 mg/L and MTBE concentrations decreased from 30 to <5 mg/L. These results indicate that microorganisms indigenous to the groundwater system at this site can degrade milligram per liter concentrations of MTBE under natural and artificial oxic conditions.

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

PubMed

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

2005-10-01

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

Effect of (3,5,6-trimethylpyrazin-2-yl)methyl 2-[4-(2-methylpropyl)phenyl]propanoate (ITE), a newly developed anti-inflammatory drug, on type II collagen-induced arthritis in mice.

PubMed

Ma, Tao; Cao, Ying-Lin; Xu, Bei-Bei; Zhou, Xiao-Mian

2004-06-01

The effect of (3,5,6-trimethylpyrazin-2-yl)methyl 2-[4-(2-methylpropyl)phenyl]propanoate (ITE) on type II collagen (CII)-induced arthritis in mice was studied. Mice were immunized twice with CII, ITE being given orally once a day for 40 d after the 1st immunization. Clinical assessment showed that ITE had no effect on the day of onset of arthritis but did lowered the incidence rate of arthritis and the arthritis score. And ITE had a marked suppressive effect on the mouse hind paw edema induced by CII. ITE suppressed the delayed-type mouse ear skin reaction to CII but had no effect on the level of serum anti-CII antibodies. These results suggest that ITE inhibits the development of CII-induced arthritis in mice by suppressing delayed-type hypersensitivity to CII.

Complexes of dichloro[2-(dimethylaminomethyl)phenyl-C1,N]gold(III), [Au(damp-C1,N)Cl2], with formylferrocene thiosemicarbazones: synthesis, structure and cytotoxicity.

PubMed

Casas, José S; Castaño, María V; Cifuentes, María C; García-Monteagudo, Juán C; Sánchez, Agustín; Sordo, José; Abram, Ulrich

2004-06-01

Dichloro[2-(dimethylaminomethyl)phenyl- phenyl-C1,N]gold(III), [Au(damp-C1,N)Cl2], reacts with the formylferrocene thiosemicarbazones derived from 4-methyl-, 4-phenyl-, 4-ethyl- and 4,4-dimethyl-3-thiosemicarbazides, HFcTSC, to give complexes of general formula [Au(Hdamp-1C)Cl(FcTSC)]Cl. These complexes were isolated and characterized by elemental analysis, mass spectrometry and IR, 1H NMR and (13)C NMR spectroscopy. In some cases, cyclic voltammetric studies were carried out and these showed that the complexation of gold affects the redox behaviour of the ferrocene unit. The in vitro antitumor activity against the HeLa cell line was also determined for the more soluble complexes. The IC(50) values were found to be higher than that of cisplatin but the maximum antiproliferative activity was similar.

Anaerobic degradation of polychlorinated biphenyls (PCBs) and polychlorinated biphenyls ethers (PBDEs), and microbial community dynamics of electronic waste-contaminated soil.

PubMed

Song, Mengke; Luo, Chunling; Li, Fangbai; Jiang, Longfei; Wang, Yan; Zhang, Dayi; Zhang, Gan

2015-01-01

Environmental contamination caused by electronic waste (e-waste) recycling is attracting increasing attention worldwide because of the threats posed to ecosystems and human safety. In the present study, we investigated the feasibility of in situ bioremediation of e-waste-contaminated soils. We found that, in the presence of lactate as an electron donor, higher halogenated congeners were converted to lower congeners via anaerobic halorespiration using ferrous ions in contaminated soil. The 16S rRNA gene sequences of terminal restriction fragments indicated that the three dominant strains were closely related to known dissimilatory iron-reducing bacteria (DIRB) and those able to perform dehalogenation upon respiration. The functional species performed the activities of ferrous oxidation to ferric ions and further ferrous reduction for dehalogenation. The present study links iron cycling to degradation of halogenated materials in natural e-waste-contaminated soil, and highlights the synergistic roles of soil bacteria and ferrous/ferric ion cycling in the dehalogenation of polychlorinated biphenyls (PCBs) and polybrominated biphenyl ethers (PBDEs). Copyright © 2014 Elsevier B.V. All rights reserved.

Treatment of halogen-containing waste and other waste materials

DOEpatents

Forsberg, Charles W.; Beahm, Edward C.; Parker, George W.

1997-01-01

A process for treating a halogen-containing waste material. The process provides a bath of molten glass containing a sacrificial metal oxide capable of reacting with a halogen in the waste material. The sacrificial metal oxide is present in the molten glass in at least a stoichiometric amount with respect to the halogen in the waste material. The waste material is introduced into the bath of molten glass to cause a reaction between the halogen in the waste material and the sacrificial metal oxide to yield a metal halide. The metal halide is a gas at the temperature of the molten glass. The gaseous metal halide is separated from the molten glass and contacted with an aqueous scrubber solution of an alkali metal hydroxide to yield a metal hydroxide or metal oxide-containing precipitate and a soluble alkali metal halide. The precipitate is then separated from the aqueous scrubber solution. The molten glass containing the treated waste material is removed from the bath as a waste glass. The process of the invention can be used to treat all types of waste material including radioactive wastes. The process is particularly suited for separating halogens from halogen-containing wastes.

Understanding How the Presence of Uniform Electric Fields Can Shift the Miscibility of Polystyrene/Poly(vinyl methyl ether) Blends

NASA Astrophysics Data System (ADS)

Kriisa, Annika; Roth, Connie B.

2015-03-01

Techniques which can externally control and manipulate the phase behavior of polymeric systems, without altering chemistry on a molecular level, have great practical benefits. One such possible mechanism is the use of electric fields, shown to cause interfacial instabilities, orientation of morphologies, and phase transitions in polymer blends and block copolymers. We have recently demonstrated that the presence of uniform electric fields can also strongly enhance the miscibility of polystyrene (PS) / poly(vinyl methyl ether) (PVME) blends [J. Chem. Phys. 2014, 141, 134908]. Using fluorescence to measure the phase separation temperature Ts of PS/PVME blends with and without electric fields, we show that Ts can be reproducibly and reversibly increased by 13.5 +/- 1.4 K for electric fields of 17 kV/mm for this lower critical solution temperature (LCST) blend. This increase in blend miscibility with electric fields represents some of the largest absolute shifts in Ts ever recorded, well outside of experimental error. The best theoretical prediction for the expected shift in Ts with electric field for this system is still two orders of magnitude smaller than that observed experimentally. We discuss the limitations of this theoretical prediction and consider possible factors affecting miscibility that may need to be also included.

Halogen-free boron based electrolyte solution for rechargeable magnesium batteries

NASA Astrophysics Data System (ADS)

Zhu, Jinjie; Guo, Yongsheng; Yang, Jun; Nuli, Yanna; Zhang, Fan; Wang, Jiulin; Hirano, Shin-ichi

2014-02-01

All halogen containing electrolytes for Mg battery are apt to corrode conventional metal current collectors. In this paper, a new type of halogen-free boron based electrolyte (Mg[Mes3BPh]2/THF) is designed and prepared. Electrochemical tests show that this electrolyte system possesses high ion conductivity (1.5 × 10-3 S cm-1) and good Mg deposition-dissolution reversibility. More importantly, the same electrochemical window (2.6 V vs. Mg RE) of the electrolyte on Pt and stainless steel electrodes indicates that halogen-free electrolyte indeed lessens the corrosion to conventional metal current collectors. The surface morphologies of stainless steel, aluminum and copper are further observed after their anodic potentiostatic polarization in 0.25 mol L-1 Mg[Mes3BPh]2/THF electrolyte solution for 2 days. A comparison with halogen containing electrolytes proves that the presence of halogen in electrolyte is the reason for corrosion. This work provides a stepping stone for developing new halogen-free electrolyte systems for rechargeable Mg batteries.

Antioxidant and Antimicrobial Activity of 5-methyl-2-(5-methyl-1,3-diphenyl-1H-pyrazole-4-carbonyl)-2,4-dihydro-pyrazol-3-one

PubMed Central

Umesha, K. B.; Rai, K. M. L.; Harish Nayaka, M. A.

2009-01-01

Cycloaddition of nitrile imines 4 generated in situ by the catalytic dehydrogenation of diphenyl hydrazones 3 using Chloramine-T (CAT) as oxidant in glacial acetic acid with enolic form of ethyl acetoacetate 5 afforded Ethyl 3-aryl-5-methyl-1-phenyl-1H-pyrazol-4-carboxylate 6 in 80% yield. The said pyrazoles 6 refluxed with 80% hydrazine hydrate using absolute alcohol as solvent for about 2–3 hours to produce the respective 5-methyl-1,3-diphenyl-1H-pyrazole-4-carboxylic acid hydrazide 7. The alcoholic solution of pyrazole acid hydrazides on heating with ethyl acetoacetate 5 to give the 5-methyl-2-(5-methyl-1,3-diphenyl-1H-pyrazole-4-carbonyl)-2,4-dihydro-pyrazol-3-one 8. The synthesized compounds were found to exhibit good antimicrobial and antioxidant activity as evaluated by 1,1-diphenyl-2-picryl Hydrazyl (DPPH) radical scavenging, reducing power and DNA protection assays. PMID:23675159

Human cytochrome P450 isozymes in metabolism and health effects of gasoline ethers.

PubMed

Hong, J Y; Wang, Y Y; Mohr, S N; Bondoc, F Y; Deng, C

2001-05-01

To reduce the production of carbon monoxide and other pollutants in motor vehicle exhaust, methyl tert-butyl ether (MTBE*), ethyl tert-butyl ether (ETBE), and tert-amyl methyl ether (TAME) are added to gasoline as oxygenates for more complete combustion. Among them, MTBE is the most widely used. The possible adverse effect of MTBE in humans is a public concern, but the human enzymes responsible for metabolism of these gasoline ethers and the causes or factors for increased sensitivity to MTBE in certain individuals are totally unknown. This information is important to understanding the health effects of MTBE in humans and to assessing the human relevance of pharmacokinetics and toxicity data obtained from animals. In the present study, we demonstrated that human liver is active in metabolizing MTBE to tert-butyl alcohol (TBA), a major circulating metabolite and an exposure marker of MTBE. The activity is localized in the microsomal fraction but not in the cytosol. Formation of TBA in human liver microsomes is NADPH-dependent and is significantly inhibited by carbon monoxide, which inhibits cytochrome P450 (CYP) enzymes. These results provide strong evidence that CYP enzymes play a critical role in the metabolism of MTBE in human livers. Human liver is also active in the oxidative metabolism of 2 other gasoline ethers, ETBE and TAME. We observed a large interindividual variation in metabolizing these gasoline ethers in 15 microsomal samples prepared from normal human livers. The activity level (pmol metabolite/min/mg) ranged from 204 to 2,890 for MTBE; 179 to 3,134 for ETBE; and 271 to 8,532 for TAME. The microsomal activities in metabolizing MTBE, ETBE, and TAME correlated highly with each other (r = 0.91 to 0.96), suggesting that these ethers are metabolized by the same enzyme(s). Correlation analysis of the ether-metabolizing activities with individual CYP enzyme activities in the human liver microsomes showed that the highest degree of correlation was with CYP

Rotational Investigation of the Adducts of Formic Acid with Alcohols, Ethers and Esters

NASA Astrophysics Data System (ADS)

Evangelisti, Luca; Spada, Lorenzo; Li, Weixing; Caminati, Walther

2016-06-01

Mixtures of formic acid with methyl alcohol, with isopropyl alcohol, with tert-butyl alcohol, with dimethylether and with isopropylformiate have been supersonically expanded as pulsed jets. The obtained cool plumes have been analyzed by Fourier transform microwave spectroscopy. It has been possible to assign the rotational spectra of the 1:1 adducts of formic acid with tert-butyl alcohol, with dimethyl ether and with isopropylformiate. The conformational shapes and geometries of these adducts, as well as the topologies of their itermolecular hydrogen bonds will be presented. An explanation is given of the failure of the assignments of the rotational spectra of the adducts of formic acid with methyl alcohol and isopropyl alcohol.

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

USGS Publications Warehouse

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

2008-01-01

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

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

USGS Publications Warehouse

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

1993-01-01

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.

Health Risk Assessment for Inhalation Exposure to Methyl Tertiary Butyl Ether at Petrol Stations in Southern China

PubMed Central

Hu, Dalin; Yang, Jianping; Liu, Yungang; Zhang, Wenjuan; Peng, Xiaowu; Wei, Qinzhi; Yuan, Jianhui; Zhu, Zhiliang

2016-01-01

Methyl tertiary butyl ether (MTBE), a well known gasoline additive, is used in China nationwide to enhance the octane number of gasoline and reduce harmful exhaust emissions, yet  little is known regarding the potential health risk associated with occupational exposure to MTBE in petrol stations. In this study, 97 petrol station attendants (PSAs) in southern China were recruited for an assessment of the health risk associated with inhalation exposure to MTBE. The personal exposure levels of MTBE were analyzed by Head Space Solid Phase Microextraction GC/MS, and the demographic characteristics of the PSAs were investigated. Cancer and non-cancer risks were calculated with the methods recommended by the United States Environmental Protection Agency. The results showed that the exposure levels of MTBE in operating workers were much higher than among support staff (p < 0.01) and both were lower than 50 ppm (an occupational threshold limit value). The calculated cancer risks (CRs) at the investigated petrol stations was 0.170 to 0.240 per 106 for operating workers, and 0.026 to 0.049 per 106 for support staff, which are below the typical target range for risk management of 1 × 10−6 to 1 × 10−4; The hazard quotients (HQs) for all subjects were <1. In conclusion, our study indicates that the MTBE exposure of PSAs in southern China is in a low range which does not seem to be a significant health risk. PMID:26861375

Methyl tert butyl ether is anti-angiogenic in both in vitro and in vivo mammalian model systems.

PubMed

Kozlosky, John; Bonventre, Josephine; Cooper, Keith

2013-08-01

Methyl-tertiary butyl ether (MTBE), a well known gasoline oxygenate, and US Food and Drug Administration approved gallstone treatment, has been previously shown to specifically target teleost embryonic angiogenesis. The studies reported here were to determine whether similar vascular disrupting effects occur in higher vertebrate models. Rat brain endothelial cells were isolated and allowed to form microcapillary-like tubes on Matrigel. MTBE (0.34-34.0 mm) exposure resulted in a dose-dependent reduction of tube formation, with the LOAEL at 0.34 mm, while MTBE's primary metabolite, tertiary butyl alcohol had no effect on tube formation. HUVECs, a primary cell line representing macrovascular cells, were able to form tubes on Matrigel in the presence of MTBE (1.25-80 mm), but the tubes were narrower than those formed in the absence of MTBE. In a mouse Matrigel plug implantation assay, 34.0 mm MTBE completely inhibited vessel invasion into plugs containing endothelial cell growth supplement (ECGS) compared with control plugs with ECGS alone. When timed-pregnant Fisher 344 rats were gavaged with MTBE (500-1500 mg kg(-1) ) from day 6 of organogenesis through 10 days post-parturition, no organ toxicity or histological changes in pup vasculature were observed. Results of the in vitro cell culture studies show that MTBE is anti-angiogenic at mm concentrations and has potential use as an anti-angiogenic treatment for solid tumors with minimal toxicity. Copyright © 2012 John Wiley & Sons, Ltd.

Methyl tert-butyl ether occurrence and related factors in public and private wells in southeast New Hampshire.

PubMed

Ayotte, Joseph D; Argue, Denise M; McGarry, Frederick J

2005-01-01

The occurrence of methyl tert-butyl ether (MTBE) in water from public wells in New Hampshire has increased steadily over the past several years. Using a laboratory reporting level of 0.2 microg/L, 40% of samples from public wells and 21% from private wells in southeast New Hampshire have measurable concentrations of MTBE. The rate of occurrence of MTBE varied significantly for public wells by establishmenttype; for example, 63% of public wells serving residential properties have MTBE concentrations above 0.2 microg/L, whereas lower rates were found for schools (21%). MTBE concentrations correlate strongly with urban factors, such as population density. Surprisingly, MTBE was correlated positively with well depth for public supply wells. Well depth is inversely related to yield in New Hampshire bedrock wells, which may mean that there is less opportunity for dilution of MTBE captured by deep wells. Another possibility is that the source(s) of water to low-yield wells may be dominated by leakage from potentially contaminated shallow groundwater through near-surface fractures or along the well casing. These wells may also have relatively large contributing areas (due to low recharge at the bedrock surface) and therefore have a greater chance of intersecting MTBE sources. This finding is significant because deep bedrock wells are often considered to be less vulnerable to contamination than shallow wells, and in southeast New Hampshire, wells are being drilled deeper in search of increased supply.

Health Risk Assessment for Inhalation Exposure to Methyl Tertiary Butyl Ether at Petrol Stations in Southern China.

PubMed

Hu, Dalin; Yang, Jianping; Liu, Yungang; Zhang, Wenjuan; Peng, Xiaowu; Wei, Qinzhi; Yuan, Jianhui; Zhu, Zhiliang

2016-02-06

Methyl tertiary butyl ether (MTBE), a well known gasoline additive, is used in China nationwide to enhance the octane number of gasoline and reduce harmful exhaust emissions, yet little is known regarding the potential health risk associated with occupational exposure to MTBE in petrol stations. In this study, 97 petrol station attendants (PSAs) in southern China were recruited for an assessment of the health risk associated with inhalation exposure to MTBE. The personal exposure levels of MTBE were analyzed by Head Space Solid Phase Microextraction GC/MS, and the demographic characteristics of the PSAs were investigated. Cancer and non-cancer risks were calculated with the methods recommended by the United States Environmental Protection Agency. The results showed that the exposure levels of MTBE in operating workers were much higher than among support staff (p < 0.01) and both were lower than 50 ppm (an occupational threshold limit value). The calculated cancer risks (CRs) at the investigated petrol stations was 0.170 to 0.240 per 10⁶ for operating workers, and 0.026 to 0.049 per 10⁶ for support staff, which are below the typical target range for risk management of 1 × 10(-6) to 1 × 10(-4); The hazard quotients (HQs) for all subjects were <1. In conclusion, our study indicates that the MTBE exposure of PSAs in southern China is in a low range which does not seem to be a significant health risk.

Investigating Planetary Volatile Accretion Mechanisms Using the Halogens

NASA Astrophysics Data System (ADS)

Ballentine, C. J.; Clay, P. L.; Burgess, R.; Busemann, H.; Ruzié, L.; Joachim, B.; Day, J. M.

2014-12-01

Depletion of the volatile elements in the Earth relative to the CI chondrites is roughly correlated with volatility, or decreasing condensation temperature. For the heavy halogen group elements (Cl, Br and I), volatility alone does not account for their apparent depletion, which early data has suggested is far greater than predicted [1-2]. Such depletion has been used to argue for the preferential loss of halogens by, amongst other processes, impact-driven erosive loss from Earth's surface [2]. Little consensus exists as to why the halogens should exhibit such preferential behavior during accretionary processes. Early efforts to constrain halogen abundance and understand their behavior in both Earth and planetary materials [3-6] have been hampered by their typically low abundance (ppb level) in most geologic materials. We present the results of halogen analysis of 23 chondrite samples, selected to represent diverse groups and petrologic type. Halogen abundances were measured by neutron irradiation noble gas mass spectrometry (NI-NGMS). Significant concentration heterogeneity is observed within some samples. However, a single Br/Cl and I/Cl ratio of 1.9 ± 0.2 (x 10-3) and 335 ± 10 (x 10-6) can be defined for carbonaceous chondrites with a good correlation between Br and Cl (R2 = 0.97) and between I and Cl (R2 = 0.84). Ratios of I/Cl overlap with terrestrial estimates of Bulk Silicate Earth and Mid Ocean Ridge Basalts. Similarly, good correlations are derived for enstatite (E) chondrites and a sulfide- and halogen- rich subset of E-chondrites. Chlorine abundances of CI (Orgueil) in this study are lower by factor of ~ 3 than the value of ~ 700 ppm Cl (compilation in [1]). Our results are similar to early discarded low values for Ivuna and Orgueil from [5,6] and agree more closely with values for CM chondrites. Halogens may not be as depleted in Earth as previously suggested, or a high degree of heterogeneity in the abundance of these volatile elements in

Tracing groundwater with low-level detections of halogenated VOCs in a fractured carbonate-rock aquifer, Leetown Science Center, West Virginia, USA

USGS Publications Warehouse

Plummer, Niel; Sibrell, Philip L.; Casile, Gerolamo C.; Busenberg, Eurybiades; Hunt, Andrew G.; Schlosser, Peter

2013-01-01

Measurements of low-level concentrations of halogenated volatile organic compounds (VOCs) and estimates of groundwater age interpreted from 3H/3He and SF6 data have led to an improved understanding of groundwater flow, water sources, and transit times in a karstic, fractured, carbonate-rock aquifer at the Leetown Science Center (LSC), West Virginia. The sum of the concentrations of a set of 16 predominant halogenated VOCs (TDVOC) determined by gas chromatography with electron-capture detector (GC–ECD) exceeded that possible for air–water equilibrium in 34 of the 47 samples (median TDVOC of 24,800 pg kg−1), indicating that nearly all the water sampled in the vicinity of the LSC has been affected by addition of halogenated VOCs from non-atmospheric source(s). Leakage from a landfill that was closed and sealed nearly 20 a prior to sampling was recognized and traced to areas east of the LSC using low-level detection of tetrachloroethene (PCE), methyl chloride (MeCl), methyl chloroform (MC), dichlorodifluoromethane (CFC-12), and cis-1,2-dichloroethene (cis-1,2-DCE). Chloroform (CHLF) was the predominant VOC in water from domestic wells surrounding the LSC, and was elevated in groundwater in and near the Fish Health Laboratory at the LSC, where a leak of chlorinated water occurred prior to 2006. The low-level concentrations of halogenated VOCs did not exceed human or aquatic-life health criteria, and were useful in providing an awareness of the intrinsic susceptibility of the fractured karstic groundwater system at the LSC to non-atmospheric anthropogenic inputs. The 3H/3He groundwater ages of spring discharge from the carbonate rocks showed transient behavior, with ages averaging about 2 a in 2004 following a wet climatic period (2003–2004), and ages in the range of 4–7 a in periods of more average precipitation (2008–2009). The SF6 and CFC-12 data indicate older water (model ages of 10s of years or more) in the low-permeability shale of the Martinsburg

Synthesis of [1-.sup.13C]pyruvic acid], [2-.sup.13C]pyruvic acid], [3-.sup.13C]pyruvic acid] and combinations thereof

DOEpatents

Martinez, Rodolfo A [Santa Fe, NM; Unkefer, Clifford J [Los Alamos, NM; Alvarez, Marc A [Santa Fe, NM

2009-09-01

The present invention is directed to labeled compounds, of the formulae ##STR00001## wherein C* is each independently selected from the group consisting of .sup.13C and .sup.12C with the proviso that at least one C* is .sup.13C, each hydrogen of the methylene group can independently be either hydrogen or deuterium, the methyl group includes either zero or three deuterium atoms, Q is from the group of sulfide, sulfinyl, and sulfone, Z is an aryl group from the group of 1-naphthyl, substituted 1-naphthyl, 2-naphthyl, substituted 2-naphthyl, and phenyl groups with the structure ##STR00002## wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4 and R.sub.5 are each independently from the group of hydrogen, a C.sub.1-C.sub.4 lower alkyl, a halogen, and an amino group from the group of NH.sub.2, NHR and NRR' where R and R' are each independently from the group of a C.sub.1-C.sub.4 lower alkyl, a phenyl, and an alkoxy group, and the methyl group can include either zero or three deuterium atoms.

Nucleophilic substitution rates and solubilities for methyl halides in seawater

NASA Astrophysics Data System (ADS)

Elliott, Scott; Rowland, F. Sherwood

1993-06-01

Ozone depletion potentials indicate that methyl bromide is among halogen containing gases which may be scheduled for international level regulation. The oceanic component of its global budget is currently unquantifiable because of a lack of surface seawater measurements. Given values for internal removal and for solubility, marine mixed layer modelling can set bounds for air-sea transfer. Rate constants have been measured in seawater, 0.5m NaCl and distilled water for attack on methyl bromide by the chief oceanic nucleophiles chloride ion and H2O, over much of the oceanographic temperature range (0°C to 22°C). Henry's Law constants have been determined for the same conditions. All results are consistent with classical aqueous phase research adjusted for ionic strength effects. The lifetime of methyl bromide with respect to chemical decay in seawater is three weeks at average surface temperatures, and a factor of ten larger and smaller at the extremes. Its dimensionless solubility ranges from 0.1 to 0.3. Analogous experiments are reported for the other natural methyl halides, CH3Cl and CH3I.

Persubstituted p-benzoquinone monoxime alkyl ethers and their molecular structure

NASA Astrophysics Data System (ADS)

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

2012-05-01

Theoretical and experimental approaches were applied for the investigation of the reactivity of persubstituted 4-nitrosophenols in the reaction with alkyl iodides, in particular the potassium salt of 2,6-di(alkoxycarbonyl)-3,5-dimethyl-4-nitrosophenol. Hartre-Fock calculations showed that the anion negative charge was located mostly on the oxygen of hydroxyl group, while estimation of the total energy of the alkylated products pointed out the benefit of alkylation on the oxygen atom of the nitroso group yielding p-benzoquinone monoxime alkyl ethers. Methylation and ethylation of persubstituted nitrosophenols were carried out. The products obtained were investigated using X-ray diffraction, 1Н NMR spectroscopy and mass spectrometry. The crystal structure of the methyl ether of 2,6-di(alkoxycarbonyl)-3,5-dimethyl-1,4-benzoquinone-1-oxime (С15H19NO6) (I) was determined by the X-ray powder diffraction technique. The unit cell parameters were: a = 7.3322(6) Å, b = 10.5039(12) Å, c = 21.1520(20) Å, β = 93.742(6)°, V = 1625.58(2) Å3Z = 4, Sp.Gr. P21/c. The structure modeling was made in direct space by the Monte-Carlo approach using rigid and soft restrictions. The structure refinement was completed by the Rietveld method. It was established that the alkylation occurred on the oxygen atom of the nitroso group. The molecules (I) in the crystal structure were packed in columns along the axis a with pairwise convergence in a column up to the distance of 3.63 Å due to a 180° turn of every second molecule around the column axis. In the molecular structure the methyloxime group was oriented in the benzene plane and had π-conjugation with the ring. The ethoxycarbonyl groups were turned nearly perpendicular to the ring. Other compounds obtained had the structure of the alkyl ethers of 1.4-benzoquinone-1-oxime, which was proved by 1Н NMR spectroscopy and mass-spectrometry.

Treatment of halogen-containing waste and other waste materials

DOEpatents

Forsberg, C.W.; Beahm, E.C.; Parker, G.W.

1997-03-18

A process is described for treating a halogen-containing waste material. The process provides a bath of molten glass containing a sacrificial metal oxide capable of reacting with a halogen in the waste material. The sacrificial metal oxide is present in the molten glass in at least a stoichiometric amount with respect to the halogen in the waste material. The waste material is introduced into the bath of molten glass to cause a reaction between the halogen in the waste material and the sacrificial metal oxide to yield a metal halide. The metal halide is a gas at the temperature of the molten glass. The gaseous metal halide is separated from the molten glass and contacted with an aqueous scrubber solution of an alkali metal hydroxide to yield a metal hydroxide or metal oxide-containing precipitate and a soluble alkali metal halide. The precipitate is then separated from the aqueous scrubber solution. The molten glass containing the treated waste material is removed from the bath as a waste glass. The process of the invention can be used to treat all types of waste material including radioactive wastes. The process is particularly suited for separating halogens from halogen-containing wastes. 3 figs.

40 CFR 721.522 - Oxirane, methyl-, polymer with oxirane, mono(3,5,5,-trimethylhexyl) ether.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Oxirane, methyl-, polymer with oxirane... Significant New Uses for Specific Chemical Substances § 721.522 Oxirane, methyl-, polymer with oxirane, mono(3...) The chemical substance identified as oxirane, methyl-, polymer with oxirane, mono(3,5,5...

40 CFR 721.522 - Oxirane, methyl-, polymer with oxirane, mono(3,5,5,-trimethylhexyl) ether.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Oxirane, methyl-, polymer with oxirane... Significant New Uses for Specific Chemical Substances § 721.522 Oxirane, methyl-, polymer with oxirane, mono(3...) The chemical substance identified as oxirane, methyl-, polymer with oxirane, mono(3,5,5...

40 CFR 721.522 - Oxirane, methyl-, polymer with oxirane, mono(3,5,5,-trimethylhexyl) ether.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Oxirane, methyl-, polymer with oxirane... Significant New Uses for Specific Chemical Substances § 721.522 Oxirane, methyl-, polymer with oxirane, mono(3...) The chemical substance identified as oxirane, methyl-, polymer with oxirane, mono(3,5,5...

40 CFR 721.522 - Oxirane, methyl-, polymer with oxirane, mono(3,5,5,-trimethylhexyl) ether.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Oxirane, methyl-, polymer with oxirane... Significant New Uses for Specific Chemical Substances § 721.522 Oxirane, methyl-, polymer with oxirane, mono(3...) The chemical substance identified as oxirane, methyl-, polymer with oxirane, mono(3,5,5...

40 CFR 721.522 - Oxirane, methyl-, polymer with oxirane, mono(3,5,5,-trimethylhexyl) ether.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Oxirane, methyl-, polymer with oxirane... Significant New Uses for Specific Chemical Substances § 721.522 Oxirane, methyl-, polymer with oxirane, mono(3...) The chemical substance identified as oxirane, methyl-, polymer with oxirane, mono(3,5,5...

Method for halogenating or radiohalogenating a chemical compound

DOEpatents

Kabalka, George W.

2006-05-09

A method for obtaining a halogenated organic compound, whereby an organotrifluoroborate compound is reacted with a halide ion in the presence of an oxidizing agent to produce the corresponding halogenated organic compound. The method may be used for producing radiohalogenated organic compounds.

40 CFR 721.10283 - Poly[oxy(methyl-1,2-ethanediyl)], .alpha.-sulfo-.omega.-hydroxy-, C12-13-branched and linear...

Code of Federal Regulations, 2013 CFR

2013-07-01

...)], .alpha.-sulfo-.omega.-hydroxy-, C12-13-branched and linear alkyl ethers, sodium salts. 721.10283 Section... Substances § 721.10283 Poly[oxy(methyl-1,2-ethanediyl)], .alpha.-sulfo-.omega.-hydroxy-, C12-13-branched and.... (1) The chemical substance identified as poly[oxy(methyl-1,2-ethanediyl)], .alpha.-sulfo-.omega...

40 CFR 721.10284 - Poly[oxy(methyl-1,2-ethanediyl)], .alpha.-sulfo-.omega.-hydroxy-, C14-15-branched and linear...

Code of Federal Regulations, 2012 CFR

2012-07-01

...)], .alpha.-sulfo-.omega.-hydroxy-, C14-15-branched and linear alkyl ethers, sodium salts. 721.10284 Section... Substances § 721.10284 Poly[oxy(methyl-1,2-ethanediyl)], .alpha.-sulfo-.omega.-hydroxy-, C14-15-branched and.... (1) The chemical substance identified as poly[oxy(methyl-1,2-ethanediyl)], .alpha.-sulfo-.omega...

40 CFR 721.10284 - Poly[oxy(methyl-1,2-ethanediyl)], .alpha.-sulfo-.omega.-hydroxy-, C14-15-branched and linear...

Code of Federal Regulations, 2014 CFR

2014-07-01

...)], .alpha.-sulfo-.omega.-hydroxy-, C14-15-branched and linear alkyl ethers, sodium salts. 721.10284 Section... Substances § 721.10284 Poly[oxy(methyl-1,2-ethanediyl)], .alpha.-sulfo-.omega.-hydroxy-, C14-15-branched and.... (1) The chemical substance identified as poly[oxy(methyl-1,2-ethanediyl)], .alpha.-sulfo-.omega...

40 CFR 721.10283 - Poly[oxy(methyl-1,2-ethanediyl)], .alpha.-sulfo-.omega.-hydroxy-, C12-13-branched and linear...

Code of Federal Regulations, 2012 CFR

2012-07-01

...)], .alpha.-sulfo-.omega.-hydroxy-, C12-13-branched and linear alkyl ethers, sodium salts. 721.10283 Section... Substances § 721.10283 Poly[oxy(methyl-1,2-ethanediyl)], .alpha.-sulfo-.omega.-hydroxy-, C12-13-branched and.... (1) The chemical substance identified as poly[oxy(methyl-1,2-ethanediyl)], .alpha.-sulfo-.omega...

40 CFR 721.10284 - Poly[oxy(methyl-1,2-ethanediyl)], .alpha.-sulfo-.omega.-hydroxy-, C14-15-branched and linear...

Code of Federal Regulations, 2013 CFR

2013-07-01

...)], .alpha.-sulfo-.omega.-hydroxy-, C14-15-branched and linear alkyl ethers, sodium salts. 721.10284 Section... Substances § 721.10284 Poly[oxy(methyl-1,2-ethanediyl)], .alpha.-sulfo-.omega.-hydroxy-, C14-15-branched and.... (1) The chemical substance identified as poly[oxy(methyl-1,2-ethanediyl)], .alpha.-sulfo-.omega...

40 CFR 721.10283 - Poly[oxy(methyl-1,2-ethanediyl)], .alpha.-sulfo-.omega.-hydroxy-, C12-13-branched and linear...

Code of Federal Regulations, 2014 CFR

2014-07-01

...)], .alpha.-sulfo-.omega.-hydroxy-, C12-13-branched and linear alkyl ethers, sodium salts. 721.10283 Section... Substances § 721.10283 Poly[oxy(methyl-1,2-ethanediyl)], .alpha.-sulfo-.omega.-hydroxy-, C12-13-branched and.... (1) The chemical substance identified as poly[oxy(methyl-1,2-ethanediyl)], .alpha.-sulfo-.omega...

The Halogen Bond in the Design of Functional Supramolecular Materials: Recent Advances

PubMed Central

2013-01-01

Halogen bonding is an emerging noncovalent interaction for constructing supramolecular assemblies. Though similar to the more familiar hydrogen bonding, four primary differences between these two interactions make halogen bonding a unique tool for molecular recognition and the design of functional materials. First, halogen bonds tend to be much more directional than (single) hydrogen bonds. Second, the interaction strength scales with the polarizability of the bond-donor atom, a feature that researchers can tune through single-atom mutation. In addition, halogen bonds are hydrophobic whereas hydrogen bonds are hydrophilic. Lastly, the size of the bond-donor atom (halogen) is significantly larger than hydrogen. As a result, halogen bonding provides supramolecular chemists with design tools that cannot be easily met with other types of noncovalent interactions and opens up unprecedented possibilities in the design of smart functional materials. This Account highlights the recent advances in the design of halogen-bond-based functional materials. Each of the unique features of halogen bonding, directionality, tunable interaction strength, hydrophobicity, and large donor atom size, makes a difference. Taking advantage of the hydrophobicity, researchers have designed small-size ion transporters. The large halogen atom size provided a platform for constructing all-organic light-emitting crystals that efficiently generate triplet electrons and have a high phosphorescence quantum yield. The tunable interaction strengths provide tools for understanding light-induced macroscopic motions in photoresponsive azobenzene-containing polymers, and the directionality renders halogen bonding useful in the design on functional supramolecular liquid crystals and gel-phase materials. Although halogen bond based functional materials design is still in its infancy, we foresee a bright future for this field. We expect that materials designed based on halogen bonding could lead to

Emission Studies in CI Engine using LPG and Palm Kernel Methyl Ester as Fuels and Di-ethyl Ether as an Additive

NASA Astrophysics Data System (ADS)

Dora, Nagaraju; Jothi, T. J. Sarvoththama

2018-05-01

The present study investigates the effectiveness of using di-ethyl ether (DEE) as the fuel additive in engine performance and emissions. Experiments are carried out in a single cylinder four stroke diesel engine at constant speed. Two different fuels namely liquefied petroleum gas (LPG) and palm kernel methyl ester (PKME) are used as primary fuels with DEE as the fuel additive. LPG flow rates of 0.6 and 0.8 kg/h are considered, and flow rate of DEE is varied to maintain the constant engine speed. In case of PKME fuel, it is blended with diesel in the latter to the former ratio of 80:20, and DEE is varied in the volumetric proportion of 1 and 2%. Results indicate that for the engine operating in LPG-DEE mode at 0.6 kg/h of LPG, the brake thermal efficiency is lowered by 26%; however, NOx is subsequently reduced by around 30% compared to the engine running with only diesel fuel at 70% load. Similarly, results of PKME blended fuel showed a drastic reduction in the NOx and CO emissions. In these two modes of operation, DEE is observed to be significant fuel additive regarding emissions reduction.

Scientific conferences: A big hello to halogen bonding

NASA Astrophysics Data System (ADS)

Erdelyi, Mate

2014-09-01

Halogen bonding connects a wide range of subjects -- from materials science to structural biology, from computation to crystal engineering, and from synthesis to spectroscopy. The 1st International Symposium on Halogen Bonding explored the state of the art in this fast-growing field of research.

40 CFR Appendix J to Part 122 - NPDES Permit Testing Requirements for Publicly Owned Treatment Works (§ 122.21(j))

Code of Federal Regulations, 2012 CFR

2012-07-01

...-ethylhexyl) phthalate 4-bromophenyl phenyl ether Butyl benzyl phthalate 2-chloronaphthalene 4-chlorophenyl phenyl ether Chrysene Di-n-butyl phthalate Di-n-octyl phthalate Dibenzo(a,h)anthracene 1,2-dichlorobenzene 1,3-dichlorobenzene 1,4-dichlorobenzene 3,3-dichlorobenzidine Diethyl phthalate Dimethyl phthalate...

Poly(arylene ether)s That Resist Atomic Oxygen

NASA Technical Reports Server (NTRS)

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

1994-01-01

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

Quantum-chemical, NMR and X-ray diffraction studies on (+/-)-1-[3,4-(methylenedioxy)phenyl]-2-methylaminopropane.

PubMed

Zapata-Torres, Gerald; Cassels, Bruce K; Parra-Mouchet, Julia; Mascarenhas, Yvonne P; Ellena, Javier; De Araujo, A S

2008-06-01

Time-averaged conformations of (+/-)-1-[3,4-(methylenedioxy)phenyl]-2-methylaminopropane hydrochloride (MDMA, "ecstasy") in D(2)O, and of its free base and trifluoroacetate in CDCl(3), were deduced from their (1)H NMR spectra and used to calculate their conformer distribution. Their rotational potential energy surface (PES) was calculated at the RHF/6-31G(d,p), B3LYP/6-31G(d,p), B3LYP/cc-pVDZ and AM1 levels. Solvent effects were evaluated using the polarizable continuum model. The NMR and theoretical studies showed that, in the free base, the N-methyl group and the ring are preferentially trans. This preference is stronger in the salts and corresponds to the X-ray structure of the hydrochloride. However, the energy barriers separating these forms are very low. The X-ray diffraction crystal structures of the anhydrous salt and its monohydrate differed mainly in the trans or cis relationship of the N-methyl group to the alpha-methyl, although these two forms interconvert freely in solution.

Mode of Action Studies on Nitrodiphenyl Ether Herbicides 1

PubMed Central

Bowyer, John R.; Hallahan, Beverly J.; Camilleri, Patrick; Howard, Joy

1989-01-01

The nitrodiphenyl ether herbicide 5-[2-chloro-4-(trifluoromethyl)phenoxy]-2-nitroacetophenone oxime-o-(acetic acid, methyl ester) (DPEI) induces light- and O2-dependent lipid peroxidation and chlorophyll (Chl) bleaching in the green alga Scenedesmus obliquus. Under conditions of O2-limitation, these effects are diminished by prometyne and 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU), both inhibitors of photosynthetic electron transport. Mutants in which photosynthetic electron transport is blocked are also resistant to DPEI under conditions of O2-limitation. Light- and O2-dependent lipid peroxidation and Chl bleaching are also induced by 5-[2-chloro-4-(trifluoromethyl)phenoxy]-3-methoxyphthalide (DPEII), a diphenyl ether whose redox properties preclude reduction by photosystem I. However, these effects of DPEII are also inhibited by DCMU. Under conditions of high aeration, DCMU does not protect Scenedesmus cells from Chl bleaching induced by DPEI, but does protect against paraquat. DPEI, but not paraquat, induces tetrapyrrole formation in treated cells in the dark. This is also observed in a mutant lacking photosystem I but is suppressed under conditions likely to lead to O2 limitation. Our results indicate that, in contrast to paraquat, the role of photosynthetic electron transport in diphenyl ether toxicity in Scenedesmus is not to reduce the herbicide to a radical species which initiates lipid peroxidation. Its role is probably to maintain a sufficiently high O2 concentration, through water-splitting, in the algal suspension. PMID:16666600

D-deprenyl protects nigrostriatal neurons against 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced dopaminergic neurotoxicity.

PubMed

Muralikrishnan, Dhanasekharan; Samantaray, Supriti; Mohanakumar, Kochupurackal P

2003-10-01

Selegiline (L-deprenyl) is believed to render protection against l-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-neurotoxicity to a significant extent via a free radical scavenging mechanism, which is independent of its ability to inhibit monoamine oxidase-B (MAO-B) in the brain. We investigated the hydroxyl radical (.OH) scavenging action and neuroprotective effect of D-deprenyl, its less active isomer, in MPTP-induced dopaminergic neurotoxicity in mice to test whether the chemical structure of the molecule or its biological effects contribute to this property. To achieve this goal we studied the effects of D-deprenyl on: (1).OH production in a Fenton reaction; (2) MPTP-induced.OH generation and dopamine (DA) depletion in vivo, employing a sensitive HPLC-electrochemical procedure; and (3) formation of MPP(+) in vivo in the striatum following systemic administration of MPTP, employing an HPLC-photodiode array detection system. D-deprenyl inhibited ferrous citrate-induced.OH in vitro (0.45 microM) and MPTP-induced.OH in vivo in substantia nigra (SN) and in the striatum (1.0 mg/kg, i.p.). D-deprenyl did not, but L-deprenyl (0.5 mg/kg dose) did significantly inhibit formation of MPP(+) in the striatum 90 min following systemic MPTP injection. It failed to affect MAO-B activity at 0.5 mg/kg in the striatum, but effectively blocked MPTP-induced striatal DA depletion. The potency of D-deprenyl to scavenge MPTP-induced.OH in vivo and to render protection against the dopaminergic neurotoxicity without affecting dopamine turnover, MAO-B activity, or formation of MPP(+) in the brain indicates a direct involvement of.OH in the neurotoxic action of MPTP and antioxidant effect in the neuroprotective action of deprenyl. Copyright 2003 Wiley-Liss, Inc.

Crown ethers in graphene

DOE PAGES

Guo, Junjie; Lee, Jaekwang; Contescu, Cristian I.; ...

2014-11-13

Crown ethers, introduced by Pedersen1, are at their most basic level neutral rings constructed of oxygen atoms linked by two- or three-carbon chains. They have attracted special attention for their ability to selectively incorporate various atoms2 or molecules within the cavity formed by the ring3-6. This property has led to the use of crown ethers and their compounds in a wide range of chemical and biological applications7,8. However, crown ethers are typically highly flexible, frustrating efforts to rigidify them for many uses that demand higher binding affinity and selectivity9,10. In this Letter, we report atomic-resolution images of the same basicmore » structures of the original crown ethers embedded in graphene. This arrangement constrains the crown ethers to be rigid and planar and thus uniquely suited for the many applications that crown ethers are known for. First-principles calculations show that the close similarity of the structures seen in graphene with those of crown ether molecules also extends to their selectivity towards specific metal cations depending on the ring size. Atoms (or molecules) incorporated within the crown ethers in graphene offer a simple environment that can be easily and systematically probed and modeled. Thus, we expect that this discovery will introduce a new wave of investigations and applications of chemically functionalized graphene.« less

(Z)-3-(1-Chloro-prop-1-en-yl)-2-methyl-1-phenyl-sulfonyl-1H-indole.

PubMed

Umadevi, M; Saravanan, V; Yamuna, R; Mohanakrishnan, A K; Chakkaravarthi, G

2013-11-16

In the title compound, C18H16ClNO2S, the indole ring system forms a dihedral angle of 75.07 (8)° with the phenyl ring. The mol-ecular structure is stabilized by a weak intra-molecular C-H⋯O hydrogen bond. In the crystal, mol-ecules are linked by weak C-H⋯O hydrogen bonds, forming a chain along [10-1]. C-H⋯π inter-actions are also observed, leading to a three-dimensional network.

(O-Methyl di­thio­carbonato-κS)tri­phenyl­tin(IV)

PubMed Central

Javed, Fatima; Ali, Saqib; Shah, Wajid; Tahir, M. Nawaz; Ullah, Hameed

2013-01-01

In the title compound, [Sn(C6H5)3(C2H3OS2)], the SnIV atom adopts a distorted SnC3S tetra­hedral coordination geometry. A short Sn⋯O contact [2.988 (4) Å] is also present. The phenyl rings are each disordered over two sets of sites with an occupancy ratio of 0.550 (8):0.450 (8). The crystal studied was found to be a racemic twin with a twin component ratio of 0.57 (18):0.43 (18). PMID:23794982

The Important Role of Halogen Bond in Substrate Selectivity of Enzymatic Catalysis

NASA Astrophysics Data System (ADS)

Jiang, Shuiqin; Zhang, Lujia; Cui, Dongbin; Yao, Zhiqiang; Gao, Bei; Lin, Jinping; Wei, Dongzhi

2016-10-01

The use of halogen bond is widespread in drug discovery, design, and clinical trials, but is overlooked in drug biosynthesis. Here, the role of halogen bond in the nitrilase-catalyzed synthesis of ortho-, meta-, and para-chlorophenylacetic acid was investigated. Different distributions of halogen bond induced changes of substrate binding conformation and affected substrate selectivity. By engineering the halogen interaction, the substrate selectivity of the enzyme changed, with the implication that halogen bond plays an important role in biosynthesis and should be used as an efficient and reliable tool in enzymatic drug synthesis.

Tropospheric impacts of volcanic halogen emissions: first simulations of reactive halogen chemistry in the Eyjafjallajökull eruption plume

NASA Astrophysics Data System (ADS)

Roberts, Tjarda

2013-04-01

Volcanic plumes are regions of high chemical reactivity. Instrumented research aircraft that probed the 2010 Icelandic Eyjafjallajökull eruption plume identified in-plume ozone depletion and reactive halogens (Cl, BrO), the latter also detected by satellite. These measurements add to growing evidence that volcanic plumes support rapid reactive halogen chemistry, with predicted impacts including depletion of atmospheric oxidants and mercury deposition. However, attempts to simulate volcanic plume halogen chemistry and predict impacts are subject to considerable uncertainties. e.g. in rate constants for HOBr reactive uptake (see this session: EGU2013-6076), or in the high-temperature initialisation. Model studies attempting to replicate volcanic plume halogen chemistry are restricted by a paucity of field data that is required both for model tuning and verification, hence reported model 'solutions' are not necessarily unique. To this end, the aircraft, ground-based and satellite studies of the Eyjafjallajökull eruption provide a valuable combination of datasets for improving our understanding of plume chemistry and impacts. Here, PlumeChem simulations of Eyjafjallajökull plume reactive halogen chemistry and impacts are presented and verified by observations for the first time. Observed ozone loss, a function of plume strength and age, is quantitatively reproduced by the model. Magnitudinal agreement to reported downwind BrO and Cl is also shown. The model predicts multi-day impacts, with reactive bromine mainly as BrO, HOBr and BrONO2 during daytime, and Br2 and BrCl at night. BrO/SO2 is reduced in more dispersed plumes due to enhanced partitioning to HOBr, of potential interest to satellite studies of BrO downwind of volcanoes. Additional predicted impacts of Eyjafjallajökull volcanic plume halogen chemistry include BrO-mediated depletion of HOx that reduces the rate of SO2 oxidation to H2SO4, hence the formation of sulphate aerosol. The model predicts NOx is

Routes to ultra-pure alkyls of indium and gallium and their adducts with ethers, phosphines and amines

NASA Astrophysics Data System (ADS)

Jones, Anthony C.; Holliday, A. Kenneth; Cole-Hamilton, David J.; Ahmad, M. Munir; Gerrard, Neil D.

1984-09-01

Electrolysis of tetrahydrofuran (thf) solutions of dimethylmagnesium containing tetraethylammonium percholrate using a gallium anode gives [Me 3Ga·thf], but higher yields of both [Me 3Ga·thf] and [Me 3In·thf] are obtained on electrolysis of thf solutions of Grignard reagents with sacrificial metal anodes in the absence of a carrying electrolyte. The thf adducts can be converted into adducts with other Lewis bases, [ Me3M· L], M = Ga or In, L = PMe 3, PEt 3, NEt 3, by simple base exchange reactions. Base-free trimethylgallium can be prepared from: (i) reaction of methyl iodide with the intermetallic compound [Mg 5Ga 2] in a high boiling ether; (ii) electrolysis of Grignard reagents in high boiling ethers using sacrificial gallium anodes; (iii) reactions of GaCl 3 with Grignard reagents in high boiling ethers or (iv) ether exchange reaction between [Me 3Ga·OEt 2] and high boiling ethers. All of these reactions lead to adducts between trimethylgallium and the high boiling ether which, on heating, decompose to give base-free trimethylgallium. [Me 3Ga·OEt 2] can be prepared from reaction of Grignard reagents with gallium trichloride in diethylether or from electrolysis of Grignard reagents in diethyl ether using a sacrificial gallium anode. Similar reactions using an indium anode lead to [Me 3In·OEt 2] from which base-free trimethylindium can be liberated using known chemistry. The use of alkyls prepared in this way for vapour phase epitaxy as well as the purity of the alkyls are discussed.

Activation of C-O and C-C bonds and formation of novel HAlOH-ether complexes: an EPR study of the reaction of ground-state Al atoms with methylethyl ether and diethyl ether.

PubMed

Brunet, François D; Feola, Julie C; Joly, Helen A

2012-03-15

Reaction mixtures, containing Al atoms and methylethyl ether (MEE) or diethyl ether (DEE) in an adamantane matrix, were prepared with the aid of a metal-atom reactor known as a rotating cryostat. The EPR spectra of the resulting products were recorded from 77-260 K, at 10 K intervals. Al atoms were found to insert into methyl-O, ethyl-O, and C-C bonds to form CH(3)AlOCH(2)CH(3), CH(3)OAlCH(2)CH(3), and CH(3)OCH(2)AlCH(3), respectively, in the case of MEE while DEE produced CH(3)CH(2)AlOCH(2)CH(3) and CH(3)AlCH(2)OCH(2)CH(3), respectively. From the intensity of the transition lines attributed to the Al atom C-O insertion products of MEE, insertion into the methyl-O bond is preferred. The Al hyperfine interaction (hfi) extracted from the EPR spectra of the C-O insertion products was greater than that of the C-C insertion products, that is, 5.4% greater for the DEE system and 7% greater for the MEE system. The increase in Al hfi is thought to arise from the increased electron-withdrawing ability of the substituents bonded to Al. Besides HAlOH, resulting from the reaction of Al atoms with adventitious water, novel mixed HAlOH:MEE and HAlOH:DEE complexes were identified with the aid of isotopic studies involving H(2)(17)O and D(2)O. The Al and H hfi of HAlOH were found to decrease upon complex formation. These findings are consistent with the nuclear hfi calculated using a density functional theory (DFT) method with close agreement between theory and experiment occurring at the B3LYP level using a 6-311+G(2df,p) basis set.

Plant selective uptake of halogenated flame retardants at an e-waste recycling site in southern China.

PubMed

Wang, Shaorui; Wang, Yan; Luo, Chunling; Li, Jun; Yin, Hua; Zhang, Gan

2016-07-01

The concentrations and homolog patterns of halogenated flame retardants (HFRs) in vegetables grown at an e-waste contaminated site were investigated. Polybrominated diphenyl ethers (PBDEs) were the dominant HFRs in vegetable tissues, with concentrations ranging from 10.3 to 164 ng g(-1) and 1.16-107 ng g(-1) in shoots and roots, respectively, followed by novel brominated flame retardants (NBFRs) and dechlorane plus (DPs). This is an indication that PBDE contamination in vegetables grown around e-waste recycling sites may pose a risk to the local terrestrial ecosystem and residents. In addition, this is the first report on the concentrations and compositions of NBFRs in vegetables around e-waste recycling sites. The HFRs concentrations in vegetables varied greatly with the vegetable species, with the highest concentrations observed in Brassica oleracea var. capitata. Root concentration factors (RCF) decreased with increasing log Kow of HFRs, which indicated that the uptake of HFRs was controlled mainly by log Kow. Dissimilar HFRs profiles in shoots and roots suggested that the uptake and translocation of HFRs by plants were selective, with lower halogenated congeners prone to accumulation in vegetable tissues. Positive relationships between PBDEs and their substitutes were observed in vegetable tissues, suggesting that the replacement of PBDEs by NBFRs has not resulted in an obvious transition in plants within the study area. Copyright © 2016 Elsevier Ltd. All rights reserved.

Catalytic oxidation of dimethyl ether

DOEpatents

Zelenay, Piotr; Wu, Gang; Johnston, Christina M.; Li, Qing

2016-05-10

A composition for oxidizing dimethyl ether includes an alloy supported on carbon, the alloy being of platinum, ruthenium, and palladium. A process for oxidizing dimethyl ether involves exposing dimethyl ether to a carbon-supported alloy of platinum, ruthenium, and palladium under conditions sufficient to electrochemically oxidize the dimethyl ether.

Down-regulation of natural resistance-associated macrophage protein-1 (Nramp1) is associated with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)/1-methyl-4-phenylpyridinium (MPP+ )-induced α-synuclein accumulation and neurotoxicity.

PubMed

Wu, K-C; Liou, H-H; Lee, C-Y; Lin, C-J

2018-04-21

The accumulation of α-synuclein is a hallmark in the pathogenesis of Parkinson's disease (PD). Natural resistance-associated macrophage protein-1 (Nramp1) was previously shown to contribute to the degradation of extracellular α-synuclein in microglia under conditions of iron overload. This study was aimed at investigating the role of Nramp1 in α-synuclein pathology in the neurone under 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)/1-methyl-4-phenylpyridinium (MPP + ) treatment. The expression of Nramp1 and pathological features (including iron and α-synuclein accumulation) were examined in the dopaminergic neurones of humans (with and without PD) and of mice [with and without receiving chronic MPTP intoxication]. The effects of Nramp1 expression on low-dose MPP + -induced α-synuclein expression and neurotoxicity were determined in human dopaminergic neuroblastoma SH-SY5Y cells. Similar to the findings in the substantia nigra of human PD, lower expression of Nramp1 but higher levels of iron and α-synuclein were identified in the dopaminergic neurones of mice receiving chronic MPTP intoxication, compared to controls. In parallel to the loss of dopaminergic neurones, the numbers of glial fibrillary acidic protein- and ionized calcium-binding adapter molecule-1-positive cells were significantly increased in the substantia nigra of MPTP-treated mice. Likewise, in human neuroblastoma SH-SY5Y cells exposed to low-dose MPP + , Nramp1 expression and cathepsin D activity were decreased, along with an increase in α-synuclein protein expression and aggregation. Overexpression of functional Nramp1 restored cathepsin D activity and attenuated α-synuclein up-regulation and neuronal cell death caused by MPP + treatment. These data suggest that the neuronal expression of Nramp1 is important for protecting against the development of MPTP/MPP + -induced α-synuclein pathology and neurotoxicity. © 2018 British Neuropathological Society.

Halogen bonding based recognition processes: a world parallel to hydrogen bonding.

PubMed

Metrangolo, Pierangelo; Neukirch, Hannes; Pilati, Tullio; Resnati, Giuseppe

2005-05-01

Halogen bonding is the noncovalent interaction between halogen atoms (Lewis acids) and neutral or anionic Lewis bases. The main features of the interaction are given, and the close similarity with the hydrogen bonding will become apparent. Some heuristic principles are presented to develop a rational crystal engineering based on halogen bonding. The focus is on halogen-bonded supramolecular architectures given by halocarbons. The potential of the interaction is shown by useful applications in the field of synthetic chemistry, material science, and bioorganic chemistry.

(E)-3-[2-(4-Chloro­phenyl­sulfon­yl)vin­yl]-6-methyl-4H-chromen-4-one

PubMed Central

Ravi Kumar, R.; Krishnaiah, M.; Oo, Thanzaw; Kaung, Pho; Jagadeesh Kumar, N.

2009-01-01

In the title compound, C18H13ClO4S, the mean planes of the chloro­phenyl ring and the S—C=C—C chain are oriented at angles of 52.7 (2) and 51.3 (2)°, respectively, with respect to the sulfonyl (O=S=O) plane. The dihedral angle between the mean planes of the chloro­phenyl group and the benzopyran ring is 80.7 (1)°. The crystal structure is stabilized by two inter­molecular C—H⋯O inter­actions, forming centrosymmetrc dimers, which are linked via a second C—H⋯O inter­action into a chain structure. PMID:21578354

Revealing charge carrier dynamics in squaraine:[6, 6]-phenyl-C 71-butyric acid methyl ester based organic solar cells

NASA Astrophysics Data System (ADS)

Rana, Aniket; Sharma, Chhavi; Prabhu, Deepak D.; Kumar, Mahesh; Karuvath, Yoosaf; Das, Suresh; Chand, Suresh; Singh, Rajiv K.

2018-04-01

Ultrafast charge carrier dynamics as well as the generation of polaron pair in squaraine (SQ) and squaraine:[6,6]-phenyl-C 71-butyric acid methyl ester (SQ:PCBM71) have been studied using ultrafast transient absorption spectroscopy (UTAS). The current study reveals that the pure SQ exhibits the creation of singlet and triplet states; however, incorporation of PCBM71 in SQ results in the formation of polaron pairs with ˜550ps lifetime, which in turn leads to the creation of free electrons in the device. We show that the considerable increment in monomolecular and bimolecular recombination in SQ:PCBM71 compared to pure SQ which describes the interfacial compatibility of SQ and PCBMC71 molecules. The present work not only provides the information about the carrier generation in SQ and SQ:PCBM71 but also gives the facts relating to the effect of PCBM71 mixing into the SQ which is very significant because the SQ has donor-acceptor-donor (D-A-D) structure and mixing one more acceptor can introduce more complex recombinations in the blend. These findings have been complimented by the charge transport study in the device using impedance spectroscopy. The various important transport parameters are transit time (τt), diffusion constant (Dn), global mobility (μ) and carrier lifetime (τr). The values of these parameters are 26.38 μs, 4.64x10-6 cm2s-1, 6.12x10-6 cm2V-1s-1 and 399 μs, respectively. To the best of our knowledge such study related to SQ is not present in the literature comprehensively.

Inhibition of thyroid hormone sulfotransferase activity by brominated flame retardants and halogenated phenolics

PubMed Central

Butt, Craig M.; Stapleton, Heather M.

2013-01-01

Many halogenated organic contaminants (HOCs) are considered endocrine disruptors and affect the hypothalamic-pituitary-thyroid axis, often by interfering with circulating levels of thyroid hormones (THs). This study investigated one potential mechanism for TH disruption, inhibition of sulfotransferase activity. One of the primary roles of TH sulfation is to support the regulation of biologically active T3 through the formation of inactive THs. This study investigated TH sulfotransferase inhibition by 14 hydroxylated polybrominated diphenyl ethers (OH-BDEs), BDE 47, triclosan, and fluorinated, chlorinated, brominated and iodinated analogues of 2,4,6-trihalogenated phenol and BPA. A new mass spectrometry-based method was also developed to measure the formation rates of 3,3′-T2 sulfate (3,3′-T2S). Using pooled human liver cytosol we investigated the influence of these HOCs on the sulfation of 3,3′-T2, a major substrate for TH sulfation. For the formation of 3,3′-T2 sulfate, the Michaelis constant (Km) was 1070 ± 120 nM and the Vmax was 153 ± 6.6 pmol/min.mg protein. All chemicals investigated inhibited sulfotransferase activity with the exception of BDE 47. The 2,4,6-trihalogenated phenols were the most potent inhibitors followed by the OH-BDEs and then halogenated BPAs. The IC50 concentrations for the OH-BDEs were primarily in the low nM range, which may be environmentally relevant. In silico molecular modeling techniques were also used to simulate OH-BDE binding with SULT1A1. This study suggests that some HOCs, including anti-microbial chemicals and metabolites of flame retardants, may interfere with TH regulation through inhibition of sulfotransferase activity. PMID:24089703

New polyarylene ethers

NASA Technical Reports Server (NTRS)

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

1986-01-01

A series of new polyarylene ethers (PAEs) were prepared from the reaction of activated dihalo compounds with various bisphenols. Measured number average molecular weights for the PAEs ranged from 13,500 to 39,400 g/mole, and glass transition temperatures varied from 152 to 280 C. Ethynyl-terminated polyarylene ethers (ETPAEs) were also prepared by endcapping hydroxy-terminated polyarylene ethers with 4-ethynylbenzoyl chloride. Structure/property relationships for the PAEs, and the advantages offered by the ETPAEs, are discussed.

Degradation of halogenated aliphatic compounds by Xanthobacter autotrophicus GJ10.

PubMed Central

Janssen, D B; Scheper, A; Dijkhuizen, L; Witholt, B

1985-01-01

A bacterium that is able to utilize a number of halogenated short-chain hydrocarbons and halogenated carboxylic acids as sole carbon source for growth was identified as a strain of Xanthobacter autotrophicus. The organism constitutively produces two different dehalogenases. One enzyme is specific for halogenated alkanes, whereas the other, which is more heat stable and has a higher pH optimum, is specific for halogenated carboxylic acids. Haloalkanes were hydrolyzed in cell extracts to produce alcohols and halide ions, and a route for the metabolism of 1,2-dichlorethane is proposed. Both dehalogenases show a broad substrate specificity, allowing the degradation of bromine- and chlorine-substituted organic compounds. The results show that X. autotrophicus may play a role in the degradation of organochlorine compounds and that hydrolytic dehalogenases may be involved in the microbial metabolism of short-chain halogenated hydrocarbons in microorganisms. Images PMID:3994371

Electroreduction of Halogenated Organic Compounds

NASA Astrophysics Data System (ADS)

Rondinini, Sandra; Vertova, Alberto

The electroreductive cleavage of the carbon-halogen bond in halogenated organic compounds has been extensively studied for more than 70 years, since it is prodromal to a large variety of synthetic applications in organic electrochemistry. Over the years the research interest have progressively included the environmental applications, since several organic halocompounds are known to have (or have had) a serious environmental impact because of their (present or past) wide use as cleaning agents, herbicides, cryogenic fluids, reagents (e.g. allyl and vinyl monomers) for large production materials, etc. Recent studies have also demonstrated the wide spread out- and in-door-presence of volatile organic halides, although at low level, in connexion with residential and non-residential (e.g. stores, restaurants and transportation) activities. In this context, the detoxification of emissions to air, water and land by the selective removal of the halogen group represents a valid treatment route, which, although not leading to the complete mineralization of the pollutants, produces less harmful streams to be easily treated by electrochemical or conventional techniques. The electroreduction process is analysed and discussed in terms of electrode material, reaction medium, cell design and operation, and of substrate classification.

Disposition, metabolism, and toxicity of methyl tertiary butyl ether, an oxygenate for reformulated gasoline.

PubMed

Hutcheon, D E; Arnold, J D; ten Hove, W; Boyle, J

1996-04-05

Studies of the toxicology of methyl tertiary butyl ether (MTBE) were reviewed as a possible information base for evaluating the health effects of evaporative emissions from reformulated gasoline (RFG). The major metabolites of the oxidative demethylation of MTBE in vivo were methanol and tertiary butyl alcohol (TBA), whereas formaldehyde and TBA were the principal products of hepatic microsomal oxidation by cytochrome P-450. Pharmacokinetic studies in rats treated with intragastric MTBE in corn oil gave an initial disposition T1/2 for MTBE of 0.32 h. The decline in the serum drug versus time curve for MTBE in rats was accompanied by a progressive increase in serum methanol concentrations to levels more than 50-200 times those of the parent compound. Repeated exposure of MTBE vapor by inhalation in rats resulted in dose-dependent increases in MTBE in the blood, brain, and adipose tissue compartments. Blood concentrations of TBA were also dose dependent and provided an estimate of the total amount of MTBE distributed to peripheral drug metabolizing compartments. Perirenal fat/blood MTBE concentration ratios ranged from 9.7 to 11.6 after 15 wk of intermittent exposure. During an oxyfuels program in Fairbanks, AK, blood levels of occupationally exposed workers were 0.2-31.5 microgram/L MTBE and 1.6 to 72.2 microgram/L TBA with a mean TBA:MTBE blood concentration ratio of 4.2. In patients who received MTBE by percutaneous, transhepatic puncture for the dissolution of cholesterol gallstones, concentrations of MTBE in fat tissue reached 60 and 300 microgram/g at a treatment time when mean blood MTBE was less than 20 microgram/ml. The results of laboratory and clinical studies indicate that metabolites of MTBE may contribute to the nephropathy, neoplasms, and other pathological changes associated with repeated exposure to MTBE in experimental animals. It is concluded that such studies can provide a well-defined database for quantitative safety comparisons and health risk

Serotonin Receptor Binding Characteristics of Geissoschizine Methyl Ether, an Indole Alkaloid in Uncaria Hook

PubMed Central

Ikarashi, Yasushi; Sekiguchi, Kyoji; Mizoguchi, Kazushige

2018-01-01

Background: Geissoschizine methyl ether (GM) is one of the indole alkaloids in Uncaria hook, and an active ingredient of yokukansan (YKS) that improves behavioral and psychological symp-toms of dementia (BPSD) in patients with several types of dementia. The pharmacological action of GM has been related to various serotonin (5-HT) receptor subtypes. Objective: The aim of this article is to review the binding characteristics of GM to the 5-HT receptor sub-types in the brains using our own data and previous findings. Methods: Competitive receptor-binding and agonist/antagonist activity assays for several 5-HT receptor subtypes were performed. Moreover, the articles describing pharmacokinetics and brain distribution of GM were searched in PubMed. Results: GM bound the following 5-HT receptor subtypes: 5-HT1A, 5-HT1B, 5-HT2A, 5-HT2B, 5-HT2C, 5-HT4, 5-HT5A, 5-HT6, and 5-HT7. Among these receptors, GM had partial agonistic activity for 5-HT1A receptors and antagonistic activity for 5-HT2A, 5-HT2B, 5-HT2C, and 5-HT7 receptors. Also, GM was me-tabolized by various CYP isoforms, mainly CYP3A4. Parent/unchanged GM was detected in both the blood and brain of rats after oral administration of YKS. In the brains, GM was presumed to bind to 5-HT1A, 5-HT2A, 5-HT2B, 5-HT2C, and 5-HT7 receptors on neuron-like large cells mainly in the frontal cor-tex. Conclusion: These results suggest that GM is a pharmacologically important alkaloid that regulates vari-ous serotonergic activities or functions by binding to multiple 5-HT receptor subtypes. Thus, this review provides recent 5-HT receptor-related evidence that GM is partly responsible for pharmacological effects of YKS. PMID:28322152

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

PubMed

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

2006-05-01

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