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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 523 records · Page 29
All sourcesNASA NTRSDOE OSTI
DOE OSTI2018

Methods of dispersing carbon nanotubes

A method is described for preparing carbon nanotube dispersions in organic solvents such as chloroform and methyl ethyl ketone. Structures resulting from organic dispersions are also disclosed. The dispersing agents used in this method comprise long chain hydrocarbons, halogen-substituted hydrocarbons, fluorocarbons, or a mixture of hydrocarbons, halogen-substituted hydrocarbons, and fluorocarbons; wherein the hydrocarbons, halogen-substituted hydrocarbons and fluorocarbons have from 6 to 40 carbons in a chain, at least one alkene or alkyne moiety, and at least one pendant carboxylic acid, phosphonic acid, and/or sulfonic acid group or an ester of these acids.

Heintz, Amy M.↗
DOE OSTI2019

Ring opening of cycloalkanes at high temperatures

Cycloalkanes are an important fraction of molecules in real fuels and their pyrolysis products can be crucial during the combustion process. However, there have been few studies on the dissociation of these molecules apart from cyclohexane. We present here a laser schlieren densitometry study on cycloheptane pyrolysis as part of a study of the effect of ring size on dissociation of cycloalkanes. The experiments were performed in a diaphragmless shock tube with a 2% cycloheptane/98% krypton mixture and reaction conditions of 1400 – 2200 K and 30 – 110 Torr. Complementary investigations of the dissociation of the conjugate 1-alkene, 1-heptene (the initial pyrolysis product), have also been conducted to aid development of a chemical kinetic mechanism. A common aspect to dissociation of cycloalkanes is that at high temperatures they are efficiently converted to an allyl radical and an n-alkyl radical and the reactions of these radicals dominate the secondary chemistry. The newly developed model, which incorporates results from recent shock tube/laser schlieren studies of the n-butyl radical, is presented herein along with experimental results from cycloheptane and 1-heptene results. Good agreement between simulations and the experimental profiles were obtained allowing kinetic data to be extracted.

Chemical kinetics↗
DOE OSTI2017

Electrolyte additives for transition metal cyanometallate electrode stabilization

A method is provided for the self-repair of a transition metal cyanometallate (TMCM) battery electrode. The battery is made from a TMCM cathode, an anode, and an electrolyte including solution formed from a solvent and an alkali or alkaline earth salt. The electrolyte includes an additive represented as G-R-g: where G and g are independently include materials with nitrogen (N) sulfur (S), oxygen (O), or combinations of the above-recited elements; and where R is an alkene or alkane group. In response to charging and discharging the battery in a plurality of cycles, the method creates vacancies in a surface of the TMCM cathode. Then, the method fills the vacancies in the surface of the TMCM cathode with the electrolyte additive. An electrolyte and TMCM battery using the above-mentioned additives are also provided.

25 ENERGY STORAGE↗
DOE OSTI2019

Conversion of acetone and/or alcohol(s) to alcohol(s) and/or aliphatic hydrocarbons

A process for the production of saturated or unsaturated aliphatic alcohols and/or hydrocarbons includes condensing acetone and/or alcohol(s) to form one or more carbonyl compounds, and hydrogenating and/or hydrodeoxygenating at least one of the one or more carbonyl compounds to form the saturated or unsaturated alcohol(s) and/or hydrocarbons. In some embodiments, the condensation of acetone and/or alcohol(s) may be carried out in the presence of a solid acid catalyst and a transition metal catalyst. The saturated or unsaturated aliphatic alcohols and/or hydrocarbons may include one or more saturated linear C9 alcohols, C9 alkanes and/or one or more mono-unsaturated C9 alkenes.

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

Conversion of ethane to ethylene

Methods of converting ethane to ethylene at relatively low temperatures are described. Ir02-based catalysts are used in the conversion. Methods of converting a base gas to a first gas by exposing the base gas to an IrO2-based catalyst and forming the first gas are described. The base gas can be an alkane. The first gas can include an alkene, an alkyne, an alcohol, an aldehyde, or combinations thereof.

Weaver, Jason F.↗
DOE OSTI2022

Phosphorus-containing solid catalysts and reactions catalyzed thereby, including synthesis of p-xylene

Methods and phosphorus-containing solid catalysts for catalyzing dehydration of cyclic ethers (e.g., furans, such as 2,5-dimethylfuran) and alcohols (e.g., ethanol and isopropanol). The alcohols and cyclic ethers may be derived from biomass. One example includes a tandem Diels-Alder cycloaddition and dehydration of biomass-derived 2,5-dimethyl-furan and ethylene to renewable p-xylene. The phosphorus-containing solid catalysts are also active and selective for dehydration of alcohols to alkenes.

Cho, Hong Je↗
DOE OSTI2023

Conversion of ethane to ethylene

Methods of converting ethane to ethylene at relatively low temperatures are described. IrO2-based catalysts are used in the conversion. Methods of converting a base gas to a first gas by exposing the base gas to an IrO2-based catalyst and forming the first gas are described. The base gas can be an alkane. The first gas can include an alkene, an alkyne, an alcohol, an aldehyde, or combinations thereof.

Weaver, Jason F.↗
DOE OSTI2023

Ionic functionalization of aromatic polymers for ion exchange membranes

The electrochemical energy conversion system of the present disclosure includes an anode, a cathode, and an ion exchange membrane including a polymer having an aromatic polymer chain and an alkylated substrate including an alkyl chain, and at least one ionic group. The alkylated substrate is bound to at least one aromatic group in the polymer chain via Friedel-Crafts alkylation of the at least one aromatic group. The alkylation reaction utilizes a haloalkylated tertiary alcohol or a haloalkylated alkene as a precursor. In the presence of an acid catalyst, a carbocation is generated in the precursor which reacts with the aromatic rings of the polymer chain. The at least one ionic group is then replaced with a desired cationic or anionic group using a substitution reaction. The membranes exhibit advantageous stability achieved through a simplified and scalable reaction scheme.

Bae, Chulsung↗
DOE OSTI2012

A Combined Gas-Phase Photoelectron Spectroscopic and Theoretical Study of Zeise's Anion and Its Bromine and Iodine Analogues

We report the first photoelectron spectroscopic study of Zeise’s anion, [PtCl3(C2H4)], and its Br- and I- analogs in the gas phase. Well-resolved and rich spectral features are obtained for each species, yielding detailed electronic structure information, which is assigned with the aid of highlevel electronic structure calculations at the Coupled Cluster (CC) level of theory. The electron binding energies of [PtX3(C2H4)] are found to decrease with the size of halogen (4.57, 4.51, and 4.18 eV for X = Cl, Br, and I, respectively). The calculations indicate a synergistic η2 interaction [with interaction strengths of 1.54 (Cl), 1.37 (Br) and 1.10 eV (I)] between the perpendicular C2H4 fragment and the nearly horizontal planar PtX3- anions, resulting in activating the ethylene molecule. The detailed insights of the chemical bonding and underlying electronic structure can be used to benchmark interactions between olefins and transition metal complexes, which are crucial to a wide range of catalytic processes.

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

A Molecular Compound for Highly Selective Purification of Ethylene

Purification of C 2 H 4 from an C 2 H 4 /C 2 H 6 mixture is one of the most challenging separation processes, which is achieved mainly through energy-intensive, cryogenic distillation in industry. Sustainable, non-distillation methods are highly desired as alternatives. We discovered that the fluorinated bis(pyrazolyl)borate ligand supported copper(I) complex {[(CF 3 ) 2 Bp]Cu} 3 has features very desirable in an olefin–paraffin separation material. It binds ethylene exclusively over ethane generating [(CF 3 ) 2 Bp]Cu(C 2 H 4 ). This molecular compound exhibits extremely high and record ideal adsorbed solution theory (IAST) C 2 H 4 /C 2 H 6 gas separation selectivity, affording high purity (>99.5 %) ethylene that can be readily desorbed from separation columns. In-situ PXRD provides a “live” picture of the reversible conversion between [(CF 3 ) 2 Bp]Cu(C 2 H 4 ) and the ethylene-free sorbent in the solid-state, driven by the presence or removal of C 2 H 4 . As a result, molecular structures of trinuclear {[(CF 3 ) 2 Bp]Cu} 3 and mononuclear [(CF 3 ) 2 Bp]Cu(C 2 H 4 ) are also presented.

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

Chemical Transformation of Cat Cracking Light Gas Oil Components by Hydrofining on Aluminum-Cobalt-Molybdenum Catalysts

The degree of hydrogenation of various classes of aromatic and olefin hydrocarbons in the cat cracking light gas oil hydrofining process in the presence of Al-Co-Mo and Al-Ni-W catalysts is studied. The Al-Ni-W catalyst exhibits much greater hydrogenation activity with respect to aromatic hydrocarbons than the Al-Co-Mo catalyst. However, the Al-Co-Mo catalyst exhibits much greater hydrogenation activity with respect to olefin hydrocarbons than the Al-Ni-W catalyst.

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

Effect of the Phase Composition of Catalysts Derived from Y-type Modified Zeolite on the Yield of C8 Hydrocarbons in the Alkylation of Isobutane by Olefins

Deviations in the activity parameters of previously synthesized catalysts derived from Y-type modified zeolite from the parameters of the basic phase composition (number of aluminum atoms in the unit cell, SiO{sub 2}/Al{sub 2}O{sub 3} ratio, unit cell size) are described. The results of a study of the structural changes in the crystalline phase of the zeolite upon its post-synthesis modification are presented.

2-METHYLPROPANE↗
DOE OSTI2019

Modelling and simulation of a porous core photonic crystal fibre for terahertz wave propagation

A porous core photonic crystal fibre based on conventional hexagonal lattice cladding is proposed for propagating terahertz radiation. The structure is designed and theoretically investigated using full vectorial finite element method. Simulation results show that at 300 µm core diameter, with a high porosity of 85%, and an operating frequency of 1.3 THz, the proposed fibre reduces the bulk absorption loss of cyclic olefin copolymer (TOPAS) by about 81%, which corresponds to an ultra-low effective material loss value of 0.039 cm{sup −1}. Furthermore, the proposed fibre shows near zero dispersion coefficient of 0.47 ps/THz/cm with an extremely small variation of 0.05 over a broad 1.3 THz bandwidth; with confinement and bending losses investigated and found to be negligibly low. It is anticipated that the proposed waveguide can potentially be used for short range transmission of terahertz radiation in the communication window.

42 ENGINEERING↗
DOE OSTI2020

Divanadium substituted keggin [PV 2 W 10 O 40 ] on non-reducible supports-Al 2 O 3 and SiO 2 : synthesis, characterization, and catalytic properties for oxidative dehydrogenation of propane

Molecular metal oxide cluster, K 5 [α-1,2-PV 2 W 10 O 40 ] (PV 2 W 10 ), was found to have intrinsic catalytic activity for the oxidative dehydrogenation of propane with high selectivity (> 80%) to propylene at low propane conversion (0.3%). Synthesis of dispersed PV 2 W 10 in non-reducible supports, γ-Al 2 O 3 and SiO 2 , was done by incipient wetness impregnation. The supported catalysts were characterized by IR, Raman spectroscopy, nitrogen adsorption, x-ray powder diffraction (PXRD), elemental analysis, hydrogen temperature-programmed reduction (H 2 –TPR), and ammonia temperature-programmed desorption (NH 3 –TPD). Catalytic testing of the supported PV 2 W 10 at equimolar cluster concentration revealed that when supported in γ-Al 2 O 3 it is more active (sevenfold increase in propane conversion) but in SiO 2 it is more selective to propylene (94%). The observed performance was due to both an increase in reducibility and higher concentration of strong acid sites for PV 2 W 10 supported in γ-Al 2 O 3 versus SiO 2 . Lastly, PV 2 W10 was shown to remain intact under reaction conditions indicating its thermal and oxidative stability.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2017

Reactivity of alkyl iodides in molecular decomposition reactions

The experimental results for the concerted molecular decomposition of alkyl iodides RI to olefin and HI were analyzed in terms of the intersecting parabolas model (IPM). The activation energies (E) and rate constants (k) of the earlier unstudied reactions of the concerted molecular decomposition of RI were calculated on the basis of the enthalpy of the reaction and IPM algorithms. The factors that influence on E of RI decay were established: the enthalpy of the reaction, the energy of stabilization of radical R*, the length and force constant of the C—I bond, and the size of the halogen atom. The values of E and k for the backward reactions of HI addition to olefins were estimated.

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

Concerted cycloaddition reactions: a study using the parabolic model and quantum chemical modeling

Concerted cycloaddition reactions were studied by the method of intersecting parabolas (M3IP) and quantum chemical calculations. Experimental data were processed within the framework of the M3IP method and an algorithm for calculating the activation energies (E) and rate constants (k) for reactions from the enthalpies of reactions was developed. The parameters E and k for twelve cycloaddition reactions not studied previously were calculated. Factors affecting the activation energies were established and evaluated; these include the enthalpy of reaction, substituents, and the molecular structure of reactants. Quantum chemical modeling and topological analysis of transition states (TS) of six concerted cycloaddition reactions were performed. Depending on structure of the starting olefins, the TS of reactions can have either a symmetric or asymmetric geometry. This influences their electronic structures, the energies of chemical bonds, and the activation energies of reactions. A comparison of the activation energy values obtained from the M3IP and DFT(B3lyp/6-311++G** ) calculations revealed good agreement between them.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗