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Results for “Pyridines”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1981

Cross-linked polyvinyl pyridine coated glass particle catalyst support and aqueous composition or polyvinyl pyridine adducted microspheres

Microspheres are produced by cobalt gamma radiation initiated polymerization of a dilute aqueous vinyl pyridine solution. Addition of cross-linking agent provides higher surface area beads. Addition of monomers such as hydroxyethylmethacrylate acrylamide or methacrylamide increases hydrophilic properties and surface area of the beads. High surface area catalytic supports are formed in the presence of controlled pore glass substrate.

Rembaum, Alan↗
NASA NTRS2014

Investigation of Pyridine Carboxylic Acids in CM2 Carbonaceous Chondrites: Potential Precursor Molecules for Ancient Coenzymes

The distribution and abundances of pyridine carboxylic acids (including nicotinic acid) in eight CM2 carbonaceous chondrites (ALH 85013, DOM 03183, DOM 08003, EET 96016, LAP 02333, LAP 02336, LEW 85311, and WIS 91600) were investigated by liquid chromatography coupled to UV detection and high resolution Orbitrap mass spectrometry. We find that pyridine monocarboxylic acids are prevalent in CM2-type chondrites and their abundance negatively correlates with the degree of pre-terrestrial aqueous alteration that the meteorite parent body experienced. We also report the first detection of pyridine dicarboxylic acids in carbonaceous chondrites. Additionally, we carried out laboratory studies of proton-irradiated pyridine in carbon dioxide-rich ices (a 1:1 mixture) to serve as a model of the interstellar ice chemistry that may have led to the synthesis of pyridine carboxylic acids. Analysis of the irradiated ice residue shows that a comparable suite of pyridine mono- and dicarboxylic acids was produced, although aqueous alteration may still play a role in the synthesis (and ultimate yield) of these compounds in carbonaceous meteorites. Nicotinic acid is a precursor to nicotinamide adenine dinucleotide, a likely ancient molecule used in cellular metabolism in all of life, and its common occurrence in CM2 chondrites may indicate that meteorites may have been a source of molecules for the emergence of more complex coenzymes on the early Earth.

precursor molecules↗
NASA NTRS2014

Investigation of Pyridine Carboxylic Acids in CM2 Carbonaceous Chondrites: Potential Precursor Molecules for Ancient Coenzymes

The distribution and abundances of pyridine carboxylic acids (including nicotinic acid) in eight CM2 carbonaceous chondrites (ALH 85013, DOM 03183, DOM 08003, EET 96016, LAP 02333, LAP 02336, LEW 85311, and WIS 91600) were investigated by liquid chromatography coupled to UV detection and high resolution Orbitrap mass spectrometry. We find that pyridine monocarboxylic acids are prevalent in CM2-type chondrites and their abundance negatively correlates with the degree of pre-terrestrial aqueous alteration that the meteorite parent body experienced. We lso report the first detection of pyridine dicarboxylic acids in carbonaceous chondrites. Additionally, we carried out laboratory studies of proton-irradiated pyridine in carbon dioxide-rich ices (a 1:1 mixture) to serve as a model of the interstellar ice chemistry that may have led to the synthesis of pyridine carboxylic acids. Analysis of the irradiated ice residue shows that a comparable suite of pyridine mono- and dicarboxylic acids was produced, although aqueous alteration may still play a role in the synthesis (and ultimate yield) of these compounds in carbonaceous meteorites. Nicotinic acid is a precursor to nicotinamide adenine dinucleotide, a likely ancient molecule used in cellular metabolism in all of life, and its common occurrence in CM2 chondrites may indicate that meteorites may have been a source of molecules for the emergence of more complex coenzymes on the early Earth.

Pyridine Carboxylic↗
NASA NTRS1970

Nuclear alkylated pyridine aldehyde polymers and conductive compositions thereof

A thermally stable, relatively conductive polymer was disclosed. The polymer was synthesized by condensing in the presence of catalyst a 2, 4, or 6 nuclear alklylated 2, 3, or 4 pyridine aldehyde or quaternary derivatives thereof to form a polymer. The pyridine groups were liked by olefinic groups between 2-4, 2-6, 2-3, 3-4, 3-6 or 4-6 positions. Conductive compositions were prepared by dissolving the quaternary polymer and an organic charge transfer complexing agent such as TCNQ in a mutual solvent such as methanol.

Rembaum, A.↗
NASA NTRS1984

Electrical properties of metal-doped pyridine-derived polyimide films

A series of polyimide films containing pyridine coordinating groups doped with cobalt or nickel ions has been examined. Using 3,3',4,4'-benzophenonetetracarboxylic acid dianhydride, films were prepared in combination with 4,4'-oxydianiline, 4,4'-dianiline sulfide, 3,3'-bis(aminopyridine) sulfide and 2,2'-dioxyphenelenebis (5,5'-aminopyridine). Room temperature volume resistivities have been found to decrease slightly with sulfur and pyridine containing diamines relative to diamines which do not contain these functionalities. Doping with cobalt and nickel additives results in further lowering of room temperature volume resistivity. Preliminary temperature profiling experiments have shown that volume resistivity decreases as T(g) is approached.

Khor, E.↗
NASA NTRS2003

Dissociative Ionization and Product Distributions of Benzene and Pyridine by Electron Impact

We report a theoretical study of the dissociative ionization (DI) and product distributions of benzene (C6H6) and pyridine (C5H5N) from their low-lying ionization channels. Our approach makes use of the fact that electronic motion is much faster than nuclear motion allowing DI to be treated as a two-step process. The first step is the electron-impact ionization resulting in an ion with the same nuclear geometry as the neutral molecule. In the second step, the nuclei relax from the initial geometry and undergo unimolecular dissociation. For the ionization process we use the improved binary-encounter dipole (iBED) model [W.M. Huo, Phys. Rev. A64,042719-I (2001)]. For the unimolecular dissociation, we use multiconfigurational self-consistent field (MCSCF) methods to determine the steepest descent pathways to the possible product channels. More accurate methods are then used to obtain better energetics of the paths which are used to determine unimolecular dissociation probabilities and product distributions. Our analysis of the dissociation products and the thresholds of their productions for benzene are compared with the recent dissociative photoionization meausurements of benzene by Feng et al. [R. Feng, G. Cooper, C.E. Brion, J. Electron Spectrosc. Relat. Phenom. 123,211 (2002)] and the dissociative photoionization measurements of pyridine by Tixier et al. [S. Tixier, G. Cooper, R. Feng, C.E. Brion, J. Electron Spectrosc. Relat. Phenom. 123,185 (2002)] using dipole (e,e+ion) coincidence spectroscopy.

Dateo, Christopher E.↗
NASA NTRS1977

Metal/polyvinyl pyridine catalytic beads

Processed microspheres of polyvinyl pyridine (PVP), copolymers of PVP and other monomers are utilized as wide range of catalytic materials for different applications.

Rembaum, A.↗
NASA NTRS1989

A scanning electron microscopy study of the macro-crystalline structure of 2-(2,4-dinitrobenzyl) pyridine

The compound, 2-(2,4-dinitrobenzyl) pyridine, was synthesized in the laboratory; an introductory level electron microscopy study of the macro-crystalline structure was conducted using the scanning electron microscope (SEM). The structure of these crystals was compared with the macrostructure of the crystal of 2-(2,4-dinitrobenzyl) pyridinium bromide, the hydrobromic salt of the compound which was also synthesized in the laboratory. A scanning electron microscopy crystal study was combined with a study of the principle of the electron microscope.

Ware, Jacqueline↗
NASA NTRS2002

Dissociative Ionization of Pyridine by Electron Impact

In order to understand the damage of biomolecules by electrons, a process important in radiation damage, we undertake a study of the dissociative ionization (DI) of pyridine (C5H5N) from the low-lying ionization channels. The methodology used is the same as in the benzene study. While no experimental DI data are available, we compare the dissociation products from our calculations with the dissociative photoionization measurements of Tixier et al. using dipole (e, e(+) ion) coincidence spectroscopy. Comparisons with the DI of benzene is also made so as to understand the difference in DI between a heterocyclic and an aromatic molecule.

Dateo, Christopher↗
NASA NTRS1980

Polyvinyl pyridine microspheres

Microspheres are produced by cobalt gamma radiation initiated polymerization of a dilute aqueous vinyl pyridine solution. Addition of cross-linking agent provides higher surface area beads. Addition of monomers such as hydroxyethylmethacrylate acrylamide or methacrylamide increases hydrophilic properties and surface area of the beads. High surface area catalytic supports are formed in the presence of controlled pore glass substrate.

Rembaum, Alan↗
NASA NTRS1978

Cationic vinyl pyridine copolymers and products thereof

Quaternized, cross-linked, insoluble copolymers of unsubstituted and substituted vinyl pyridines and a dihalo organic compound are spontaneously formed at ambient temperature on mixing the two monomers in bulk, in solution or in suspension. The amount of cross-linking may be varied according to the composition and reaction conditions. The polymer product exhibits ion exchange capacity and undergoes a reversible color change from black at a pH above 7 to yellow at a pH below 7. The polymer may be formed in the presence of preformed polymers, substrates such as porous or impervious particles or films to deposit an ion exchange film in situ or on the surface of the substrate. The coated or resin impregnated substrate may be utilized for separation of anionic species from aqueous solution.

Rembaum, Alan↗
NASA NTRS1979

Polyvinyl pyridine microspheres

Microspheres are produced by cobalt gamma radiation initiated polymerization of a dilute aqueous vinyl pyridine solution. Addition of cross-linking agent provides higher surface area beads. Addition of monomers such as hydroxyethylmethacrylate acrylamide or methacrylamide increases hydrophilic properties and surface area of the beads. High surface area catalytic supports are formed in the presence of controlled pore glass substrate.

Rembaum, Alan↗
NASA NTRS1972

Separate physiological roles for two isozymes of pyridine nucleotide-linked glycerol-3-phosphate dehydrogenase in chicken.

The isozymes considered are designated 'liver type' and 'muscle type' based on the tissue of highest concentration. Electrophoretic analysis shows that the liver type is found in small amounts or is undetectable in all tissues studied except liver. The muscle type is found in skeletal muscles and kidney. Presumptive hybrid enzymes occur at low levels in chicken liver and kidney. The tissue distribution of glyceron-3-P dehydrogenase in several birds capable of sustained flight is different than in chicken.

White, H. B., III↗
NASA NTRS1981

Graphite polystyryl pyridine (PSP) structural composites

PSP6022 M resin, PSP 6024 M resin and W 133 Thormel T 300 graphite fabric reinforced panels were fabricated and provided to NASA Ames Research Center. PSP6022 and PSP6024 characteristics, process specifications for the fabriation of prepregs and of laminates are detailed. Mechanical properties, thermomechanical properties and moisture resistance were evaluated. PSP6022 and PSP6024 appear as high performance thermostable systems, very easy to process, being soluble in MEK for prepregging and being cured at no more than 250C, and even 200C.

Malassine, B.↗