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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 343 records · Page 19
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

Interfacial Reactivity and Speciation Emerging from Na-Montmorillonite Interactions with Water and Formic Acid at 200 °C: Insights from Reactive Molecular Dynamics Simulations, Infrared Spectroscopy, and X-ray Scattering Measurements

Reactive organic fluid - mineral interactions at elevated temperatures contribute to the evolution of planetary matter. One of the less studied but important transformations in this regard involves the reactions of formic acid with naturally occurring clays such as sodium montmorillonite. To advance a mechanistic understanding of these interactions, we use ReaxFF reactive molecular dynamics simulations in conjunction with infrared (IR) spectroscopy and X-ray scattering experiments to investigate the speciation behavior of water-formic acid mixtures on sodium montmorillonite interfaces at 473 K and 1 atm. Using a newly developed reactive forcefield, we show that the experimental IR spectra of unreacted and reacted mixture can be accurately reproduced by ReaxFF/MD. We further benchmark the simulation predictions of sodium carbonate and bicarbonate formation in the clay interlayers using Small and Wide-Angle X-ray Scattering measurements. Subsequently, leveraging the benchmarked forcefield, we interrogate the pathway of speciation reactions with emphasis on carbonate, formate, and hydroxide groups elucidating the energetics, transition states, intermediates, and preferred products. Further, we also delineate the differences in reactivities and catalytic effects of clay edges, facets, and interlayers owing to their local chemical environments, which have far reaching consequences in their speciation behavior. The experimental and simulation approaches described in this study and the transferable forcefields can be applied translationally to advance the science of clay-fluid interactions for several applications including subsurface fluid storage and recovery and clay-pollutant dynamics.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2024

Hydrocarboxylation of C=C Bonds in Polycyclooctene: Progress Toward Valorization of Waste Polyolefins

Upcycling of waste polyolefins into higher-value functional polymers through chemical functionalization is a promising strategy to recover value and minimize their environmental impact. We report the hydrocarboxylation of polycyclooctene as a model for accessing ethylene acrylic acid copolymers (EAA) from waste polyethylene. The effects of various process parameters on the hydrocarboxylation were investigated. The relationship between carboxylic acid concentration and material properties, including crystallinity, melting temperature, glass transition temperature, adhesive properties, and wettability, was studied in comparison to an unfunctionalized polyethylene. Among the catalysts evaluated, Co 2 (CO) 8 exhibited relatively slow kinetics toward the hydrocarboxylation and was not compatible with 2,6-di-tert-butyl hydroxytoluene, a common additive present in commercial polyolefins. PdCl 2 (PPh 3 ) 2 exhibited a higher reactivity toward the hydrocarboxylation, though polymer gelation was observed with extended reaction times or high catalyst loadings. Carboxylic acid incorporation into the polymer was readily controlled by varying the reaction time. Altogether, the resultant COOH-functionalized polyolefins possessed properties analogous to commercial EAA.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on C by Materials Project

C crystallizes in the monoclinic Cm space group. The structure is two-dimensional and consists of one C sheet oriented in the (0, 0, 1) direction. there are forty-one inequivalent C sites. In the first C site, C is bonded in a distorted bent 120 degrees geometry to three C atoms. All C–C bond lengths are 1.42 Å. In the second C site, C is bonded in a trigonal planar geometry to three C atoms. There is one shorter (1.42 Å) and two longer (1.43 Å) C–C bond length. In the third C site, C is bonded in a trigonal planar geometry to three C atoms. All C–C bond lengths are 1.43 Å. In the fourth C site, C is bonded in a distorted bent 120 degrees geometry to three C atoms. Both C–C bond lengths are 1.42 Å. In the fifth C site, C is bonded in a trigonal planar geometry to three C atoms. There is one shorter (1.42 Å) and one longer (1.43 Å) C–C bond length. In the sixth C site, C is bonded in a trigonal planar geometry to three C atoms. Both C–C bond lengths are 1.42 Å. In the seventh C site, C is bonded in a distorted trigonal planar geometry to three C atoms. There is two shorter (1.42 Å) and one longer (1.43 Å) C–C bond length. In the eighth C site, C is bonded in a distorted trigonal planar geometry to three C atoms. There is two shorter (1.42 Å) and one longer (1.43 Å) C–C bond length. In the ninth C site, C is bonded in a distorted trigonal planar geometry to three C atoms. There is one shorter (1.42 Å) and two longer (1.43 Å) C–C bond length. In the tenth C site, C is bonded in a trigonal planar geometry to three C atoms. There is one shorter (1.42 Å) and one longer (1.43 Å) C–C bond length. In the eleventh C site, C is bonded in a trigonal planar geometry to three C atoms. There is one shorter (1.42 Å) and one longer (1.44 Å) C–C bond length. In the twelfth C site, C is bonded in a trigonal planar geometry to three C atoms. There is one shorter (1.42 Å) and one longer (1.43 Å) C–C bond length. In the thirteenth C site, C is bonded in a trigonal planar geometry to three C atoms. The C–C bond length is 1.42 Å. In the fourteenth C site, C is bonded in a trigonal planar geometry to three C atoms. The C–C bond length is 1.43 Å. In the fifteenth C site, C is bonded in a trigonal planar geometry to three C atoms. The C–C bond length is 1.44 Å. In the sixteenth C site, C is bonded in a trigonal planar geometry to three C atoms. There is one shorter (1.41 Å) and one longer (1.42 Å) C–C bond length. In the seventeenth C site, C is bonded in a trigonal planar geometry to three C atoms. There is one shorter (1.42 Å) and one longer (1.45 Å) C–C bond length. In the eighteenth C site, C is bonded in a distorted trigonal planar geometry to three C atoms. There is one shorter (1.42 Å) and one longer (1.45 Å) C–C bond length. In the nineteenth C site, C is bonded in a trigonal planar geometry to three C atoms. There is one shorter (1.37 Å) and one longer (1.42 Å) C–C bond length. In the twentieth C site, C is bonded in a single-bond geometry to three C atoms. There is one shorter (1.40 Å) and one longer (1.44 Å) C–C bond length. In the twenty-first C site, C is bonded in a trigonal planar geometry to three C atoms. There is one shorter (1.42 Å) and one longer (1.43 Å) C–C bond length. In the twenty-second C site, C is bonded in a trigonal planar geometry to three C atoms. The C–C bond length is 1.43 Å. In the twenty-third C site, C is bonded in a trigonal planar geometry to three C atoms. The C–C bond length is 1.43 Å. In the twenty-fourth C site, C is bonded in a trigonal planar geometry to three C atoms. In the twenty-fifth C site, C is bonded in a trigonal planar geometry to three C atoms. In the twenty-sixth C site, C is bonded in a bent 120 degrees geometry to two C atoms. In the twenty-seventh C site, C is bonded in a bent 120 degrees geometry to two equivalent C atoms. In the twenty-eighth C site, C is bonded in a distorted trigonal planar geometry to three C atoms. The C–C bond length is 1.42 Å. In the twenty-ninth C site, C is bonded in a bent 120 degrees geometry to two equivalent C atoms. In the thirtieth C site, C is bonded in a trigonal planar geometry to three C atoms. In the thirty-first C site, C is bonded in a distorted bent 120 degrees geometry to two equivalent C atoms. In the thirty-second C site, C is bonded in a trigonal planar geometry to three C atoms. The C–C bond length is 1.43 Å. In the thirty-third C site, C is bonded in a distorted trigonal planar geometry to three C atoms. The C–C bond length is 1.43 Å. In the thirty-fourth C site, C is bonded in a trigonal planar geometry to three C atoms. In the thirty-fifth C site, C is bonded in a trigonal planar geometry to three C atoms. The C–C bond length is 1.40 Å. In the thirty-sixth C site, C is bonded in a trigonal planar geometry to three C atoms. The C–C bond length is 1.42 Å. In the thirty-seventh C site, C is bonded in a single-bond geometry to three C atoms. In the thirty-eighth C site, C is bonded in a trigonal planar geometry to three C atoms. In the thirty-ninth C site, C is bonded in a bent 120 degrees geometry to three C atoms. The C–C bond length is 1.42 Å. In the fortieth C site, C is bonded in a trigonal planar geometry to three C atoms. The C–C bond length is 1.42 Å. In the forty-first C site, C is bonded in a trigonal planar geometry to three C atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on C by Materials Project

C crystallizes in the orthorhombic Cmcm space group. The structure is one-dimensional and consists of two C ribbons oriented in the (0, 0, 1) direction. there are twenty-one inequivalent C sites. In the first C site, C is bonded in a trigonal planar geometry to three C atoms. There are a spread of C–C bond distances ranging from 1.39–1.47 Å. In the second C site, C is bonded in a trigonal planar geometry to three C atoms. There is two shorter (1.43 Å) and one longer (1.44 Å) C–C bond length. In the third C site, C is bonded in a trigonal planar geometry to three C atoms. There are a spread of C–C bond distances ranging from 1.42–1.45 Å. In the fourth C site, C is bonded in a trigonal planar geometry to three C atoms. The C–C bond length is 1.46 Å. In the fifth C site, C is bonded in a trigonal planar geometry to three C atoms. There is one shorter (1.39 Å) and two longer (1.45 Å) C–C bond length. In the sixth C site, C is bonded in a trigonal planar geometry to three C atoms. There is one shorter (1.42 Å) and two longer (1.44 Å) C–C bond length. In the seventh C site, C is bonded to four C atoms to form edge-sharing CC4 tetrahedra. There are a spread of C–C bond distances ranging from 1.52–1.60 Å. In the eighth C site, C is bonded in a trigonal planar geometry to three C atoms. The C–C bond length is 1.40 Å. In the ninth C site, C is bonded in a trigonal planar geometry to three C atoms. There is one shorter (1.41 Å) and two longer (1.44 Å) C–C bond length. In the tenth C site, C is bonded in a trigonal planar geometry to three C atoms. In the eleventh C site, C is bonded in a trigonal planar geometry to three C atoms. The C–C bond length is 1.43 Å. In the twelfth C site, C is bonded in a trigonal planar geometry to three C atoms. The C–C bond length is 1.45 Å. In the thirteenth C site, C is bonded in a trigonal planar geometry to three C atoms. In the fourteenth C site, C is bonded in a trigonal planar geometry to three C atoms. There is one shorter (1.42 Å) and one longer (1.45 Å) C–C bond length. In the fifteenth C site, C is bonded to four C atoms to form edge-sharing CC4 tetrahedra. Both C–C bond lengths are 1.52 Å. In the sixteenth C site, C is bonded in a trigonal planar geometry to three C atoms. In the seventeenth C site, C is bonded in a trigonal planar geometry to three C atoms. The C–C bond length is 1.38 Å. In the eighteenth C site, C is bonded in a trigonal planar geometry to three C atoms. In the nineteenth C site, C is bonded in a trigonal planar geometry to three C atoms. In the twentieth C site, C is bonded in a trigonal planar geometry to three C atoms. There is two shorter (1.42 Å) and one longer (1.47 Å) C–C bond length. In the twenty-first C site, C is bonded in a trigonal planar geometry to three C atoms.

36 MATERIALS SCIENCE↗