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Results for “ETHYLENE OXIDE”

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
NASA NTRS1976

Measurements of air pollutants over a Los Angeles freeway with a bistatic laser system

Nitric oxide, ozone, and ethylene were monitored over roads during periods of heavy traffic by transmitting several known laser wavelengths over an atmospheric path and measuring the differential absorption of the wavelengths. Heavy afternoon traffic between four and five o'clock over a 3.75 km path produced a noticeable increase in ethylene and a decrease in ozone. The changes occurred on a short time scale and correlated with the sudden traffic density increase. The ozone decrease occurs because of the sudden presence of large quantities of nitric oxide. Although the laboratory laser equipment used is rather cumbersome, the measurements did point out the potential of the laser absorption technique for monitoring large areas from one location.-

Menzies, R. T.↗
DOE OSTI2025

Elucidating Gas Reduction Effects of Organosilicon Additives in Lithium-Ion Batteries

Lithium-ion batteries (LIBs) with nonaqueous liquid electrolytes are prone to gas generation at elevated voltages and temperatures, degrading battery performance and posing serious safety risks. Organosilicon (OS) additives are an emerging candidate solution for gassing problems in LIBs, but a detailed understanding of their functional mechanisms remains elusive. In this work, we present a combined computational and experimental study to elucidate the gasreducing effects of OS additives. Cell volume measurements and gas chromatography–mass spectrometry reveal that OS additives can substantially reduce gas evolution in LIBs, particularly CO 2 regardless of source. Through density functional theory calculations, we identify multiple plausible pathways for CO 2 evolution, including (1) nucleophile-induced ring-opening of ethylene carbonate (EC) and the subsequent electro-oxidation and (2) direct electro-oxidation of lithium carbonate (Li 2 CO 3 ). Correspondingly, we find that OS additives function via two primary mechanisms: (1) scavenging of nucleophiles such as superoxide (O 2 •– ), peroxide (O 2 2– ), and carbonate ion (CO 3 2– ); (2) oligomerization with ethylene carbonate oxide ion and ethylene dicarbonate ion. Moreover, we discover that OS additives possess strong lithium coordination affinity, which helps further reduce the nucleophilic reaction energies and hence increases their nucleophile-scavenging efficiency. Finally, we provide a mechanistic interpretation for the enhanced gasreduction effects observed with fluorinated OS compounds, corroborated by surface analysis results from X-ray photoelectron spectroscopy. Our study offers the first molecular-level insights into how OS additives contribute to reduced gas formation in LIBs, paving the way for improved safety and performance of LIBs.

25 ENERGY STORAGE↗
DOE OSTI2025

Numerical Investigation of Susceptor-Catalyst Design for Ethylene Generation in Radio Frequency Based Reactors

Ethylene is the most widely produced petrochemical component in the world. Whether reactors are heated directly or indirectly via steam, manufacturers use economies of scale to overcome inherent thermodynamic inefficiencies when burning fossil fuels. While allowing large-scale operations to use alternative sources of energy and raw materials, new methods of supplying energy to chemical reactor systems can reduce the energy waste produced by conventional processes. One viable method for effectively supplying energy to reactor systems is electromagnetic (EM) induction heating. Using the properties of radio frequency (RF) waves, heterogeneous catalysts can be precisely targeted for heating inside reactors. Site-selective heating can greatly lower the energy requirements of the process by supplying heat to reaction sites while reducing needless heat transfer elsewhere. In this study, a microscale model was used to help create guidelines for susceptors and catalysts to improve ethylene production. The oxidative dehydrogenation of ethane is investigated by utilizing several catalysts and potential catalyst/susceptor combinations, with heat provided by an EM susceptor. Having the susceptors and catalyst function separately results in higher gradients in both heat and mass transfer, which drives transport through the catalyst region, while still providing adequate heating for endothermic reactions. However, using a susceptive core with a catalyst covering produces the maximum ethylene concentration.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2026

Direct Observation of Hydroxyls Formed from Water and Oxygen on Ag(100)

The interaction of oxygen with silver is a key descriptor of the catalytic reactivity of silver nanoparticles which are ubiquitous in large-scale partial oxidation reactions like ethylene epoxidation. Despite Ag(100) being proposed as the most selective facet, it is less studied than (111) and (110) surfaces. Using scanning tunneling microscopy and synchrotron X-ray photoelectron spectroscopy, we report that, in addition to the well-known O adatoms formed from O 2 dissociation on Ag(100), hydroxyl groups (OH), at a binding energy of ∼ 531 eV, are also present. The O/OH ratio depends on exposure to water and surface temperature. These assignments are consistent with our density functional theory calculations, which indicate that the formation of two OH groups from an O atom and H 2 O molecule is exothermic. These results indicate that, in addition to O, OH is present even under ultrahigh vacuum conditions and therefore should be considered in proposed catalytic pathways.

36 MATERIALS SCIENCE↗
NASA NTRS1996

Heterogeneous Photocatalytic Oxidation of Atmospheric Trace Contaminants

Heterogeneous photocatalysis involves the use of a light-activated catalyst at room temperature in order to carry out a desired reaction. In the presence of molecular oxygen, illumination of the n-type semiconductor oxide titanium dioxide (TiO2) provides for production of highly active forms of oxygen, such as hydroxyl radicals, which are able to carry out the complete oxidative destruction of simple hydrocarbons such as methane, ethane, ethylene, propylene, and carbon monoxide. This broad oxidation potential, coupled with the ability with sufficient residence time to achieve complete oxidation of simple hydrocarbon contaminants to carbon dioxide and water, indicated that heterogeneous photocatalysis should be examined for its potential for purification of spacecraft air. If a successful catalyst and photoreactor could be demonstrated at the laboratory level, such results would allow consideration of photocatalysts as a partial or complete replacement of adsorption systems, thereby allowing for reduction in lift-off weight of a portion of the life support system for the spacecraft, or other related application such as a space station or a conventional commercial aircraft. The present research was undertaken to explore this potential through achievement of the following plan of work: (a) ascertain the intrinsic kinetics of conversion of pollutants of interest in spacecraft, (b) ascertain the expected lifetime of catalysts through examination of most likely routes of catalyst deactivation and regeneration, (c) model and explore experimentally the low pressure drop catalytic monolith, a commercial configuration for automotive exhaust control, and (d) examine the kinetics of multicomponent conversions. In the recent course of this work, we have also discovered how to increase catalyst activity via halide promotion which has allowed us to achieve approximately 100% conversion of an aromatic contaminant (toluene) in a very short residence time of 5-6 milliseconds.

Ollis, David F.↗
NASA NTRS1996

Heterogeneous Photocatalytic Oxidation of Atmospheric Trace Contaminants

Heterogeneous photocatalysis involves the use of a light-activated catalyst at room temperature in order to carry out a desired reaction. In the presence of molecular oxygen, illumination of the n-type semiconductor oxide titanium dioxide (TiO2) provides for production of highly active forms of oxygen, such as hydroxyl radicals, which are able to carry out the complete oxidative destruction of simple hydrocarbons such as methane, ethane, ethylene, propylene, and carbon monoxide. This broad oxidation potential, coupled with the ability with sufficient residence time to achieve complete oxidation of simple hydrocarbon contaminants to carbon dioxide and water, indicated that heterogeneous photocatalysis should be examined for its potential for purification of spacecraft air. If a successful catalyst and photoreactor could be demonstrated at the laboratory level, such results would allow consideration of photocatalysts as a partial or complete replacement of adsorption systems, thereby allowing for reduction in lift-off weight of a portion of the life support system for the spacecraft, or other related application such as a space station or a conventional commercial aircraft. The present research was undertaken to explore this potential through achievement of the following plan of work: (a) ascertain the intrinsic kinetics of conversion of pollutants of interest in spacecraft, (b) ascertain the expected lifetime of catalysts through examination of most likely routes of catalyst deactivation and regeneration (c) model and explore experimentally the low pressure drop catalytic monolith, a commercial configuration for automotive exhaust control (d) examine the kinetics of multicomponent conversions. In the recent course of this work, we have also discovered how to increase catalyst activity via halide promotion which has allowed us to achieve approximately 100% conversion of an aromatic contaminant (toluene) in a very short residence time of 5-6 milliseconds.

Ollis, David F.↗
DOE OSTI2025

CO Adsorbates Induced Framework-Associated Low-Valence Co δ+ Sites in Co-ZSM-5 for Ethane Dehydrogenation

The dynamic structural evolution of heterogeneous catalysts is a ubiquitous phenomenon that has attracted a lot of interest. Catalyst reconstruction can occur after appropriate pretreatment, resulting in more efficient active catalysts, which is an attractive but challenging issue. Here, we reveal a CO activation strategy that controls the microenvironment of the Co sites in the high-silica Co-ZSM-5 catalyst (denoted as 0.50Co-Z5(340)), resulting in three times higher initial conversion and superior regeneration durability in the ethane dehydrogenation reaction compared to the same catalyst without CO pretreatment. In situ spectroscopy and metadynamics simulations reveal that the Co 2+ sites in 0.50Co-Z5(340) dislodge from the framework and move toward the nearby Brønsted acid sites, forming framework-associated low-valence Co δ+ species. Mechanistic studies indicate that the Co δ+ species catalyze ethane C–H bond cleavage via an oxidative addition mechanism, and ethylene is produced simultaneously with H* coupling (direct pathway). The promoted C–H bond activation and facile ethylene desorption explain the superior ethane dehydrogenation performance of the herein CO preactivated 0.50Co-Z5(340) catalyst.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
NASA NTRS1991

Metal etching composition

The present invention is directed to a chemical etching composition for etching metals or metallic alloys. The composition includes a solution of hydrochloric acid, phosphoric acid, ethylene glycol, and an oxidizing agent. The etching composition is particularly useful for etching metal surfaces in preparation for subsequent fluorescent penetrant inspection.

Otousa, Joseph E.↗
DOE OSTI2025

Rhodium‐Catalyzed Oxidative Alkenylation of Naphthalene: Factors That Influence Reaction at the β‐ versus α‐Position

The catalyst precursor [(η 2 -C 2 H 4 ) 2 Rh(μ-OAc)] 2 and in situ oxidant Cu(OPiv) 2 (OPiv = t-BuCOO – ) convert naphthalene and olefins (i.e., ethylene and propylene) to alkenylnaphthalenes. Under all reaction conditions tested, the functionalization is selective for the β-position of naphthalene with the highest observed β:α ratio >20:1. The β-selectivity is catalyst controlled, but oxidant identity, ethylene pressure, and olefin identity influence the ratio of β-alkenylation to α-alkenylation. The concentration of HOPiv and naphthalene do not have an effect on the β:α ratio under the reaction conditions tested. Arenes similar to naphthalene (i.e., o-xylene and 1,2,3,4-tetrahydronaphthalene) give quantitative selectivity for alkenylation at the position β to the substituent. Using propylene as the olefin for naphthalene alkenylation, the β:α ratio is 32(7):1. and the anti-Markovnikov to Markovnikov ratio is 16(2):1.

Alkenes↗
NASA NTRS1982

Air pollutant production by algal cell cultures

The production of phytotoxic air pollutants by cultures of Chlorella vulgaris and Euglena gracilis is considered. Algal and plant culture systems, a fumigation system, and ethylene, ethane, cyanide, and nitrogen oxides assays are discussed. Bean, tobacco, mustard green, cantaloupe and wheat plants all showed injury when fumigated with algal gases for 4 hours. Only coleus plants showed any resistance to the gases. It is found that a closed or recycled air effluent system does not produce plant injury from algal air pollutants.

Fong, F.↗
NASA NTRS2000

Structure of Laminar Permanently Blue, Opposed-Jet Ethylene-Fueled Diffusion Flames

The structure and state relationships of laminar soot-free (permanently blue) ethylene-fueled diffusion flames at various strain rates were studied both experimentally and computationally using an opposed-jet configuration. Measurements of gas velocities, temperatures, and compositions were carried out along the stagnation stream line. Corresponding predictions of flame structure were obtained, based on numerical simulations using several contemporary reaction mechanisms for methane oxidation. Flame conditions studied included ethylene-fueled opposed-jet diffusion flames having stoichiometric mixture fractions of 0.7 with measurements involving strain rates of 60-240/s and predictions involving strain rates of 0-1140/s at normal temperature and pressure. It was found that measured major gas species concentrations and temperature distributions were in reasonably good agreement with predictions using mechanisms due to GRI-Mech and Peters and that effects of preferential diffusion significantly influence flame structure even when reactant mass diffusivities are similar. Oxygen leakage to fuel-rich conditions and carbon monoxide leakage to fuel-lean conditions both increased as strain rates increased. Furthermore, increased strain rates caused increased fuel concentrations near the flame sheet, decreased peak gas temperatures, and decreased concentrations of carbon dioxide and water vapor throughout the flames. State relationships for major gas species and gas temperatures were found to exist over a broad range of strain rates, providing potential for significant computational simplifications for modeling purposes in some instances.

Lin, K.-C.↗
NASA NTRS2000

Structure of Laminar Permanently Blue, Opposed-Jet Ethylene-Fueled Diffusion Flames

The structure and state relationships of laminar soot-free (permanently blue) ethylene-fueled diffusion flames at various strain rates were studied both experimentally and computationally using an opposed-jet configuration. Measurements of gas velocities, temperatures, and compositions were carried out along the stagnation stream line. Corresponding predictions of flame structure were obtained, based on numerical simulations using several contemporary reaction mechanisms for methane oxidation. Flame conditions studied included ethylene-fueled opposed-jet diffusion flames having stoichiometric mixture fractions of 0.7 with measurements involving strain rates of 60-240/s and predictions involving strain rates of 0-1140/s at normal temperature and pressure. It was found that measured major gas species concentrations and temperature distributions were in reasonably good agreement with predictions using mechanisms due to GRI-Mech and Peters and that effects of preferential diffusion significantly influence flame structure even when reactant mass diffusivities are similar. Oxygen leakage to fuel-rich conditions and carbon monoxide leakage to fuel-lean conditions both increased as strain rates increased. Furthermore, increased strain rates caused increased fuel concentrations near the flame sheet, decreased peak gas temperatures, and decreased concentrations of carbon dioxide and water vapor throughout the flames. State relationships for major gas species and gas temperatures were found to exist over a broad range of strain rates, providing potential for significant computational simplifications for modeling purposes in some instances.

Lin, K.-C.↗
DOE OSTI2024

Experimental Combustion and Flame Characterization of a Chemical Looping-Based Oxidative Dehydrogenation Byproduct Fuel Mixture Containing High CO2 Dilution

Abstract This study investigates the combustion performance of a CO2-rich fuel mixture containing ethane and methane as active species using a constant volume combustion chamber. This fuel is obtained as a byproduct of a chemical looping-based oxidative dehydrogenation (Cl-ODH) process ethylene production. The byproduct gas mixture has 40.79% CO2, 39.49% ethane, and 4.88% methane by weight with other minor compounds. Using this fuel for energy extraction would improve the process efficiency of the ethane to ethylene conversion. After initial combustion modeling, the gas fuel mixture was reduced to just the major species: CO2, ethane, and methane. The mixture was then tested for flammability limits and combustion performance under spark-ignition conditions. Effects of ambient conditions like temperatures between 300 and 400 K with initial pressures from 1 to 10 bar were tested. The effects of stoichiometry were tested to understand flame velocities and heat release. The fuel mixture showed an overall reduced flame velocity compared to gasoline. Instability in combustion was believed to be caused by the dissociation of ethane under elevated conditions. At higher pressures, the flame produces lower cumulative heat release. Simulations were also performed using a model tuned to replicate the operations of the combustion chamber used in the experiments. Heat release and unburnt fuel mass data were calculated to identify the discrepancies in the combustion completeness at elevated pressures. The effects of CO2 quenching the flame coupled with the increased dissociation of the fuel species can lead to up to more than 75% of the fuel mixture being unburnt. Data from this study were used to modify a small-scale spark-ignition engine to use this fuel and produce usable energy.

Energy & Fuels↗
NASA NTRS1995

An analysis of alternative technologies for the removal of ethylene from the CELSS biomass production chamber

A variety of technologies were analyzed for their potential to remove ethylene from the CELSS Biomass Production Chamber (BPC). During crop production (e.g., lettuce, wheat, soybean, potato) in the BPC ethylene can accumulate in the airspace and subsequently affect plant viability. The chief source of ethylene is the plants themselves which reside in plastic trays containing nutrient solution. The main sink for ethylene is chamber leakage. The removal technology can be employed when deleterious levels (e.g., 50 ppb for potato) of ethylene are exceeded in the BPC and perhaps to optimize the plant growth process once a better understanding is developed of the relationship between exogenous ethylene concentration and plant growth. The technologies examined were catalytic oxidation, molecular sieve, cryotrapping, permanganate absorption, and UV degradation. Upon analysis, permanganate was chosen as the most suitable method. Experimental data for ethylene removal by permanganate during potato production was analyzed in order to design a system for installation in the BPC air duct. In addition, an analysis of the impact on ethylene concentration in the BPC of integrating the Breadboard Scale Aerobic Bioreactor (BSAB) with the BPC was performed. The result indicates that this unit has no significant effect on the ethylene material balance as a source or sink.

Rakow, Allen L.↗
NASA NTRS2011

Detection of Carbon Monoxide Using Polymer-Carbon Composite Films

A carbon monoxide (CO) sensor was developed that can be incorporated into an existing sensing array architecture. The CO sensor is a low-power chemiresistor that operates at room temperature, and the sensor fabrication techniques are compatible with ceramic substrates. Sensors made from four different polymers were tested: poly (4-vinylpryridine), ethylene-propylene-diene-terpolymer, polyepichlorohydrin, and polyethylene oxide (PEO). The carbon black used for the composite films was Black Pearls 2000, a furnace black made by the Cabot Corporation. Polymers and carbon black were used as received. In fact, only two of these sensors showed a good response to CO. The poly (4-vinylpryridine) sensor is noisy, but it does respond to the CO above 200 ppm. The polyepichlorohydrin sensor is less noisy and shows good response down to 100 ppm.

Homer, Margie L.↗
DOE OSTI2025

CO 2 Oxidative Ethane Dehydrogenation on CeO 2 /SiO 2 ‐Supported NiFe 3 Catalysts

CO 2 -assisted oxidative dehydrogenation of ethane is a sustainable alternative to steam cracking for ethylene production. In this study, a series of CeO 2 on SiO 2 supported NiFe 3 catalysts were synthesized by incipient wetness impregnation and tested for oxidative dehydrogenation performance. The CeO 2 /SiO 2 supported catalysts with high weight loading of CeO 2 (50%–75%) provided higher activity than the lower CeO 2 (0%–25%) loaded catalysts (with ethylene production rates of 0.62–0.98 µmol/g cat /s and 0.19–0.3 µmol/g cat /s, respectively) while maintaining high ethylene selectivity (43%–45%). In contrast, the NiFe 3 supported on only CeO 2 also exhibited high activity (ethylene production rate of 0.71 µmol/g cat /s), but the ethylene selectivity (16%) was greatly decreased compared to the mixed system. Temperature programmed reduction, X-ray diffraction, and Raman spectroscopy all indicate the creation of a solid solution of the Fe and Ni doped into the CeO 2 crystal structure in the catalysts with high CeO 2 loading/bulk CeO 2 support. Here, the high ethylene selectivity in the high CeO 2 loading catalysts indicates that the Fe is preferentially creating the solid solution, with the decrease in selectivity observed in the CeO 2 -only supported catalyst likely resulting from CeO 2 interacting directly with Ni, creating Ni-CeO X interfaces that are known active sites for the unwanted side reaction of dry reforming.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2025

Enhanced Selectivity for C 2 H 4 Production from C 2 H 6 on Partially Chlorinated IrO 2 (110) Surfaces

Modifying metal oxide surfaces to limit their oxidizing activity can provide a means of improving catalytic selectivity toward the partial oxidation of light alkanes. Here, in this study, we investigated the oxidation of C 2 H 6 on Cl-modified IrO 2 (110) surfaces using temperature-programmed reaction spectroscopy (TPRS) and first-principles microkinetic modeling. We find that substituting Cl for O in the IrO 2 (110) surface enhances the selectivity for C 2 H 6 conversion to C 2 H 4 during TPRS by suppressing extensive oxidation to CO x products, while also either enhancing C 2 H 4 production or altering it to a lesser extent, depending on the initial C 2 H 6 coverage. The C 2 H 4 selectivity increased with increasing C 2 H 6 and Cl coverage, but reached a limiting value below 50%. The Cl coverage changed negligibly during C 2 H 6 oxidation, and the surface reactivity decreased only marginally for Cl coverages up to 0.5 ML (monolayer). TPRS simulations using a microkinetic model predict C 2 H 4 and CO x product yields as a function of the Cl coverage that agree closely with the experimental results. According to the simulations, C 2 H 6 conversion to C 2 H 4 occurs on Cl-IrO 2 (110) by the hydrogenation of C 2 H 3 * species adsorbed in blocked states, in which neighboring sites are occupied only by unreactive HO and Cl species. The microkinetic modeling shows that H-hopping away from surface HO groups provides a relatively efficient route for C 2 H 3 * to escape blocked configurations and dehydrogenate, and that this process can limit the C 2 H 4 selectivity on Cl-IrO 2 (110) under the conditions studied. Overall, our results demonstrate that Cl-substitution into IrO 2 (110) enhances the selectivity for C 2 H 4 production from C 2 H 6 and provides insights into the reaction mechanism that can guide strategies to further improve the C 2 H 4 selectivity.

IrO2↗