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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 145 records · Page 8
All sourcesNASA NTRSDOE OSTI
DOE OSTI2017

Efficient carbon-supported heterogeneous molybdenum-dioxo catalyst for chemoselective reductive carbonyl coupling

Reductive coupling of various carbonyl compounds to the corresponding symmetric ethers with dimethylphenylsilane is reported using a carbon-supported dioxo-molybdenum catalyst. The catalyst is air- and moisture-stable and can be easily separated from the reaction mixture for recycling. In addition, the catalyst is chemoselective, thus enabling the synthesis of functionalized ethers without requiring sacrificial ligands or protecting groups.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2018

Weakly interacting solvation spheres surrounding a calixarene-protected tetrairidium carbonyl cluster: contrasting effects on reactivity of alkane solvent and silica support

The tetrairidium carbonyl cluster Ir 4 L 3 (CO) 9 (L = tert-butyl-calix[4]arene(OPr) 3 (OCH 2 PPh 2 ) (Ph = phenyl; Pr = propyl)) on a partially dehydroxylated silica support undergoes hydrogen activation at a rate and with a mechanism different from those pertaining to the cluster in alkane solution. These results are unobvious in view of the sterically bulky ligands protecting the cluster and the nearly identical CO band frequencies in the infrared spectra characterizing the supported and dissolved Ir 4 L 3 (CO) 9 , both before reaction and during reaction involving decarbonylation in the presence of either helium or H 2 (and H 2 reacted with the clusters to form hydrides with the same Ir–H band frequencies for clusters in alkane solvent and supported on silica). The initial rates of CO loss from the supported clusters in the presence of helium were the same as those in the presence of H 2 . In this work, the comparison demonstrates that the rate-determining step for hydride formation on the silica-supported cluster is CO dissociation. In contrast, the comparable dissociation of CO from the cluster in n-decane solution requires a higher temperature, 343 K, and is at least an order of magnitude slower than when the clusters were supported on silica. CO dissociation is not the rate-determining step for hydrogen activation on the cluster in n-decane, as the rate is influenced by reactant H 2 as well.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2021

Catalyst carbonylation: a hidden, but essential, step in reaction initiation

The proliferation of increasingly useful reactions for hydrogen transfer in organic synthesis has included the introduction of many new homogeneous catalysts into the organic synthesis lexicon. Unlike the proliferation of palladium-based cross-coupling reactions in which the mechanism is generally conserved, we are learning that these emerging hydrogen transfer catalysts have a rich diversity of mechanisms for catalyst activation, speciation, C–H bond cleavage and formation, and ultimately deactivation. We find that an underappreciated commonality in the catalytic activation for some of these systems is the generation of a (carbonyl)metal group, which dominates the downstream speciation of the catalyst system. In this mini-review we highlight a few well-documented cases of this phenomenon as food for thought for those who are designing new catalytic systems to introduce into this dynamic and impactful area.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2022

A nitrogen- and carbonyl-rich conjugated small-molecule organic cathode for high-performance sodium-ion batteries

Organic-based cathode materials have attracted considerable attention for sustainable Na-ion batteries due to their great promise to overcome the issues arising from the insertion of large Na + into the rigid structures of conventional transition-metal-containing inorganic electrodes. The structural flexibility as a result of weak intermolecular interactions and simple electron- and ion-storage mechanisms found in organic compounds ensure facile and reversible transport of Na ions. In order to address the general drawbacks of small-molecule organic electrodes such as material dissolution in commonly used organic electrolytes and poor electronic conductivity, we report the use of a nitrogen- and carbonyl-rich highly extended π-conjugated small molecule, hexaazatrianthranylene (HATA) embedded quinone (HATAQ), as a cathode for sodium-ion batteries. The unique hydrogen bonds between highly functionalized conjugated HATAQ molecules allow supramolecular graphite-like 2D layered arrangements in the solid state which help facilitate the structural stability during long-term cycling and promote charge transfer. The compound delivers a capacity as high as 460 mA h g -1 at 500 mA g -1 and an excellent capacity retention of 99% (~138 mA h g -1 ) after 5000 cycles at an extremely high rate of 60 A g -1 . The reaction kinetics and redox mechanism of the material have been elucidated by several characterization techniques together with density functional theory (DFT) studies. The insights gained in this work could pave the way for ultra-high-performance small-molecule organic cathodes for sustainable energy storage.

25 ENERGY STORAGE↗
DOE OSTI2014

Sources and sinks of carbonyl sulfide in an agricultural field in the Southern Great Plains

Net photosynthesis is the largest single flux in the global carbon cycle, but controls over its variability are poorly understood because there is no direct way of measuring it at the ecosystem scale. We report observations of ecosystem carbonyl sulfide (COS) and CO 2 fluxes that resolve key gaps in an emerging framework for using concurrent COS and CO 2 measurements to quantify terrestrial gross primary productivity. At a wheat field in Oklahoma we found that in the peak growing season the flux-weighted leaf relative uptake of COS and CO 2 during photosynthesis was 1.3, at the lower end of values from laboratory studies, and varied systematically with light. Due to nocturnal stomatal conductance, COS uptake by vegetation continued at night, contributing a large fraction (29%) of daily net ecosystem COS fluxes. In comparison, the contribution of soil fluxes was small (1–6%) during the peak growing season. Upland soils are usually considered sinks of COS. In contrast, the well-aerated soil at the site switched from COS uptake to emissions at a soil temperature of around 15 °C. We observed COS production from the roots of wheat and other species and COS uptake by root-free soil up to a soil temperature of around 25 °C. Our dataset demonstrates that vegetation uptake is the dominant ecosystem COS flux in the peak growing season, providing support of COS as an independent tracer of terrestrial photosynthesis. However, the observation that ecosystems may become a COS source at high temperature needs to be considered in global modeling studies.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2015

Seasonal fluxes of carbonyl sulfide in a midlatitude forest

Significance The flux of carbonyl sulfide (OCS) provides a quantitative, independent measure of biospheric activity, especially stomatal conductance and carbon uptake, at the ecosystem scale. We describe the factors controlling the hourly, daily, and seasonal fluxes of OCS based on 1 year of observations in a forest ecosystem. Vegetation dominated uptake of OCS, with daytime fluxes accounting for 72% of the total uptake for the year. Nighttime fluxes had contributions from both incompletely closed stomata and soils. Net OCS emission was observed at high temperature in summer. Diurnal and seasonal variations in OCS flux show variable stoichiometry relative to photosynthetic uptake of CO 2 . An effective model framework is shown, using an explicit representation of ecosystem processing of OCS.

Commane, Róisín↗
DOE OSTI2018

Angle dependence of strong-field single and double ionization of carbonyl sulfide

We have studied, experimentally and theoretically, the ionization probability of carbonyl sulfide (OCS) molecules in intense linearly polarized 800-nm laser pulses as a function of the angle between the molecular axis and the laser polarization. Experimentally, the molecules are exposed to two laser pulses with a relative time delay. The first, weaker pulse induces a nuclear rotational wave packet within each molecule such that the ensemble exhibits preferential alignment in the laboratory frame at specific times. The second, stronger pulse induces ionization, and the variation in single and double ionization yields is measured as a function of the delay between the two pulses. The angular dependence of the ionization yield is extracted by fitting the delay-dependent yields to a sum of delay-dependent moments of the rotational wave packet's angular distribution. We compute these same angular-dependent strong-field ionization yields for OCS using time-dependent density-functional theory (TDDFT). For the single-ionization case, our measurements agree well with TDDFT calculations and with previous experiments. Furthermore, analysis of the simulated one-body density reveals that, when averaged over a laser cycle, the resulting hole is delocalized across the molecule for light polarized perpendicular to the molecular axis and mostly localized on the sulfur for parallel polarization. Furthermore, this suggests that preferential molecular alignment is a key parameter for controlling charge migration dynamics initiated by strong-field ionization. For double ionization, the agreement between experiment and theory is less compelling, reflecting the substantial challenges of computing double-ionization yields using TDDFT methods.

74 ATOMIC AND MOLECULAR PHYSICS↗
DOE OSTI2018

N , N , N -Trimethyl-5-[(2,3,5,6-tetrafluorophenoxy)carbonyl]pyridin-2-aminium trifluoromethanesulfonate a precursor for the synthesis of 2,3,5,6-tetrafluorophenyl 6-[ 18 F]-fluoronicotinate

The synthesis, recrystallization, and X-ray deterimination of N , N , N -trimethyl-5-[(2,3,5,6-tetrafluorophenoxy)carbonyl]pyridin-2-aminium trifluoromethanesulfonate (PyTFP-precursor), C 15 H 13 F 4 N 2 O 2 + ·CF 3 SO 3 - , is described. This triflate salt precursor is required for the synthesis of 2,3,5,6-tetrafluorophenyl 6-[ 18 F]-fluoronicotinate ([ 18 F]FPyTFP), a prosthetic group used to radiolabel peptides for positron emission tomography (PET), as peptides are increasingly being used as PET-imaging probes in nuclear medicine. Radiolabeling of peptides is typically done using a `prosthetic group', a small synthon to which the radioisotope is attached in the first step, followed by attachment to the peptide in the second step. During the synthesis of the PyTFP-precursor, displacement of a Cl atom with trimethylamine gas and anion replacement with a triflate counter-ion is critical, as incomplete replacement would hinder radioisotopic incorporation of nucleophilic fluorine-18 and result in diminished radiochemical yields. The structural determination of the PyTFP-precursor by X-ray crystallography helped confirm the anion exchange of chloride with triflate.

Chemistry↗
DOE OSTI2012

Understanding the Factors Affecting the Formation of Carbonyl Iron Electrodes in Rechargeable Alkaline Iron Batteries

Rechargeable iron-based alkaline batteries such as iron - air and nickel - iron batteries are attractive for large-scale electrical energy storage because iron is inexpensive, globally-abundant and environmentally-friendly. Further, the iron electrode is known for its robustness to repeated charge/discharge cycling. During manufacturing these batteries are charged and discharged 20 to 50 times during which the discharge capacity of the iron electrode increases gradually and attains a stable value. This process of achieving stable capacity is called formation. In this study we have focused our efforts on understanding the effect of electrode design on formation. We have investigated the role of wetting agent, pore-former additive, and sulfide additive on the formation of carbonyl iron electrodes. The wetting agent increased the rate of formation while the pore-former additive increased the final capacity. Sodium sulfide added to the electrolyte worked as a de-passivation agent and increased the final discharge capacity. We have proposed a phenomenological model for the formation process that predicts the rate of formation and final discharge capacity given the design parameters for the electrode. The understanding gained here will be useful in reducing the time lost in formation and in maximizing the utilization of the iron electrode. (C) 2012 The Electrochemical Society. [DOI: 10.1149/2.021301jes] All rights reserved.

Manohar, AK↗
DOE OSTI2015

Beyond alkyl transfer: Synthesis of main group metal (Mg, Ca, Zn) silyl and tris(oxazolinyl)borato complexes and their stoichiometric and catalytic reactions with borane Lewis acids and carbonyls

Recently, the fundamental knowledge of main group metal chemistry has grown. This progress is crucial for the further development of main group metal compounds in silicon chemistry and catalysis and for advancing their applications as green alternatives to many rare earth and transition metal compounds. This thesis focuses on reactivity beyond the welldocumented alkyl-transfer applications for main group metals, and it highlights examples of reactions with Lewis acids and the reduction of carbonyls.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2021

Accelerated Aging of Fast Pyrolysis Bio-Oil Using Carbonyl Titration: Laboratory Analytical Procedure (LAP)

This laboratory analytical procedure covers the accelerated aging of fast pyrolysis bio-oils. Bio-oils undergo reactions that result in physical and chemical changes over time. These changes typically result in an increase in molecular weight, decrease in some functional groups such as carbonyls, and an increase in viscosity; additionally, the aging process often leads to phase separation. Studies have shown that accelerated aging of bio-oils using this method closely mimics room temperature aging for long periods of time (over 3 years). This procedure has been developed for the accelerated aging of fast pyrolysis bio-oils only. Fast pyrolysis bio-oils are more reactive than other bio-oils (e.g., catalytic fast pyrolysis) and undergo aging much more rapidly. Therefore, this procedure should only be used for fast pyrolysis bio-oil samples.

09 BIOMASS FUELS↗
DOE OSTI2024

Iron Carbonyl Complexes of [2.2.2]Hericene as a Rigid Tris(1,3-diene) Ligand

Hericene is an unusual hexaolefin consisting of three 1,3-diene units located on a rigid bicyclo [2.2.2]octane framework that restricts the geometrical relationships of metal atoms bonded to these olefinic units. In order to explore possible effects of this rigidity limiting metal–metal interaction in polynuclear derivatives possibly stabilizing coordinatively unsaturated species, the structures and energetics of the hericene iron carbonyl complexes (hericene)Fem(CO)n (m = 1, n = 3; m = 2, n = 6, 5; m = 3, n = 9, 8) have been investigated by density functional theory. The lowest-energy (hericene)Fem(CO)3m (m = 1, 2, 3) structures have the cavities of the hericene ligand filled with a single Fe(CO)3 moiety bonded to a 1,3-diolefin unit. Such species have been synthesized by the reaction of Fe2(CO)9 with hericene. For the (hericene)Fe2(CO)5 system, the lowest energy structures are singlet structures with an Fe(CO)3 unit bonded to a 1,3-diene unit in one hericene cavity and an Fe(CO)2 unit in another hericene cavity bonded to three C=C double bonds from two 1,3-diene units. Higher energy (hericene)Fe2(CO)5 structures include a structure in which a single hericene cavity contains a Fe2(CO)4(µ-CO) moiety with each iron atom bonded to a 1,3-diene unit. In addition, both singlet and triplet (hericene)Fe2(CO)5 structures are found in which an Fe(CO)3 moiety and an Fe(CO)2 moiety located in separate hericene cavities are each bonded to a 1,3-diene unit. The lowest-energy (hericene)Fe3(CO)8 structures have two hericene cavities containing Fe(CO)3 moieties fully bonded to 1,3-diene units and a third hericene cavity containing an Fe(CO)2 moiety fully bonded to a 1,3-diene unit.

Luo, Jinfeng↗
DOE OSTI2018

Coupled Biological and Abiotic Mechanisms Driving Carbonyl Sulfide Production in Soils

Understanding soil production of the trace gas carbonyl sulfide (OCS) is key to its use as a tracer of ecosystem function. Underlying its application is the observation that vascular plants consume atmospheric OCS via their stomatal pores in proportion with CO2 photosynthesis and that soil fluxes of OCS are negligible in comparison. Recent soil-centered studies demonstrate that soils can produce OCS and contribute as much as a quarter of the atmospheric terrestrial flux. Despite the potential widespread importance of soil OCS emissions, insufficient data exist to predict variations in OCS production across ecosystems, and the chemical and biological drivers of OCS production are virtually unknown. In this study, we address this knowledge gap by investigating variables controlling OCS soil production including soil physical and chemical properties, microbial community composition, and sulfur speciation in two independent surveys. We found that soil OCS production was nearly ubiquitous across the 58 sites, increased exponentially with temperature, and was insensitive to visible light conditioning. Soil pH, N, and C/N were predictors of OCS soil production rates in both soil surveys. Patterns in soil S speciation and predicted microbial S-cycling pathways both pointed to S-containing amino acids such as cysteine and methionine and their derivatives as potential precursors for OCS production. Elevated sulfate levels were associated with OCS production in some soils. This study provides new mechanistic insight into OCS production in soils and presents strategies to represent soil OCS fluxes that facilitate the use of OCS as a tracer for leaf-level processes related to carbon and water cycling.

Meredith, Laura K. (ORCID:0000000342444366)↗
DOE OSTI2020

Carbonyl Sulfide (OCS): Detections in Comets C/2002 T7 (LINEAR), C/2015 ER61 (PanSTARRS), and 21P/Giacobini–Zinner and Stringent Upper Limits in 46P/Wirtanen

Carbonyl sulfide (OCS) is one of the sulfur-bearing molecules detected in different astronomical environments, including comets. The present-day sulfur chemistry in comets may reveal much about the origin of these ices and their subsequent processing history. Cometary sulfur molecules such as H{sub 2}S, H{sub 2}CS, SO{sub 2}, SO, CS, CS{sub 2}, S{sub 2}, and NS have been detected in many comets. However, OCS, the only sulfur-bearing species with fluorescence emission lines at infrared wavelengths, is under-represented in comet volatile studies, having been reported in only six comets so far. We targeted OCS with the NASA Infrared Telescope Facility in comets 46P/Wirtanen, 21P/Giacobini–Zinner, and C/2015 ER61 (PanSTARRS) in 2017–2018 using the high-resolution iSHELL spectrograph, and in C/2002 T7 (LINEAR) in 2004 using the heritage CSHELL spectrograph. In comet C/2015 ER61, the OCS abundance was similar to those measured in bright comets such as comets C/2012 S1 (ISON) and C/1996 B2 (Hyakutake), whereas in C/2002 T7 it was relatively depleted. Our OCS measurement in 21P/Giacobini–Zinner is the first definitive detection of this molecule in a Jupiter-family comet from a ground-based facility and is close to the average OCS abundance determined in comet 67P/Churyumov–Gerasimenko by the Rosetta mission. Our 3σ upper limit for comet 46P/Wirtanen is the lowest reported OCS abundance in any comet. We present production rates and mixing ratios (with respect to H{sub 2}O) for these comets and place our results in the context of comets measured to date.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2016

Carbonyl sulfide exchange in soils for better estimates of ecosystem carbon uptake

Carbonyl sulfide (COS) measurements are one of the emerging tools to better quantify gross primary production (GPP), the largest flux in the global carbon cycle. COS is a gas with a similar structure to CO 2 ; COS uptake is thought to be a proxy for GPP. However, soils are a potential source or sink of COS. This study presents a framework for understanding soil–COS interactions. Excluding wetlands, most of the few observations of isolated soils that have been made show small uptake of atmospheric COS. Recently, a series of studies at an agricultural site in the central United States found soil COS production under hot conditions an order of magnitude greater than fluxes at other sites. To investigate the extent of this phenomenon, soils were collected from five new sites and incubated in a variety of soil moisture and temperature states. We found that soils from a desert, an oak savannah, a deciduous forest, and a rainforest exhibited small COS fluxes, behavior resembling previous studies. However, soil from an agricultural site in Illinois, >800 km away from the initial central US study site, demonstrated comparably large soil fluxes under similar conditions. These new data suggest that, for the most part, soil COS interaction is negligible compared to plant uptake of COS. We present a model that anticipates the large agricultural soil fluxes so that they may be taken into account. Furthermore, while COS air-monitoring data are consistent with the dominance of plant uptake, improved interpretation of these data should incorporate the soil flux parameterizations suggested here.

54 ENVIRONMENTAL SCIENCES↗