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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 1,243 records · Page 69
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Calcined Polyethyleneimine-Coated Optical Fibers for Distributed pH Monitoring at High Pressures and Temperatures

In the oil and gas, CO2 sequestration, H2 subsurface storage, and geothermal energy sectors, subsurface pH measurements are critical for monitoring the geochemical conditions and estimating potential corrosion rates of wellbore systems. Real-time pH measurements in these conditions are vital for detecting and predicting corrosion deterioration of wellbore components that may jeopardize the safety and continued operation of wellbore systems. Previous tests using metal oxide-based coatings (TiO2) provided strong responses at elevated temperatures and moderate pressure stability but provided poor differentiation between acidic and alkaline solutions. Building off the pH responsiveness of the TiO2 surface and known pH sensitivity of amine-based polymers, a coating based on the secondary amine polymer polyethyleneimine (PEI) was developed. As the polymer itself is highly water soluble and easily removed by aqueous solutions, the sensor coating was treated with a high temperature (500 °C) calcination procedure in air to convert it into a more stable oxidized coating capable of withstanding hot aqueous solutions without dissolving while retaining linear pH sensitivity from pH values between 2 and 11. The sensor performance was measured using optical transmission measurements in solutions of various pHs and using optical backscatter reflectometry for distributed pH sensing demonstration in wellbore-relevant pressures (up to 1,000 psi) and temperatures (80 °C).

Shumski, Alexander↗
DOE OSTI2018

Synthesis of Large Mesoporous–Macroporous and High Pore Volume, Mixed Crystallographic Phase Manganese Oxide, Mn 2 O 3 /Mn 3 O 4 Sponge

The controlled synthesis of mixed crystallographic phase Mn 2 O 3 /Mn 3 O 4 sponge material by varying heating rates and isothermal segments provides valuable information about the morphological and physical properties of the obtained sample. The well-characterized Mn 2 O 3 /Mn 3 O 4 sponge and applicability of difference in reactivity of H 2 and CO 2 desorbed during the synthesis provide new developments in the synthesis of metal oxide materials with unique morphological and surface properties. Here, we report the preparation of a Mn 2 O 3 /Mn 3 O 4 sponge using a metal nitrate salt, water, and Dextran, a biopolymer consisting of glucose monomers. The Mn 2 O 3 /Mn 3 O 4 sponge prepared at 1 °C·min –1 heating rate to 500 °C and held isothermally for 1 h consisted of large mesopores–macropores (25.5 nm, pore diameter) and a pore volume of 0.413 mL/g. Furthermore, the prepared Mn 2 O 3 /Mn 3 O 4 and 5 mol %–Fe-Mn 2 O 3 /Mn 3 O 4 sponges provide potential avenues in the development of solid-state catalyst materials for alcohol and amine oxidation reactions.

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

Electron-microscopic cytochemical localization of diamine and polyamine oxidases in pea and maize tissues

An electron-microscopic cytochemical method was used to localize diamine oxidase (DAO) in pea and polyamine oxidase (PAO) in maize (Zea mays L.). The method, based on the precipitation of amine-oxidase-generated H2O2 by CeCl3, was shown to be specific for DAO and PAO and permitted their localization in plant tissues with a high degree of resolution. Both enzymes are localized exclusively in the cell wall. Both DAO- and PAO-activity staining is most intense in the middle lamellar region of the wall and in cells exhibiting highly lignified walls. The oxidases could provide H2O2 for peroxidase-mediated cross-linking reactions in the cell wall and may, in this capacity, play a role in the regulation of plant growth.

NASA Program Space Biology↗
DOE OSTI2025

Understanding the Role of Hydroxyl Functionalization in Linear Poly(Ethylenimine) for Oxidation‐Resistant Direct Air Capture of CO 2

Aminopolymer-based adsorbents are a prominent class of materials being used for direct air capture of CO 2 at the industrial scale. However, improving their working lifetime, specifically by increasing their resilience to oxidative degradation, remains an ongoing challenge. Toward this end, functionalization of aminopolymers with non-amine functionalities such as hydroxyls has emerged in recent years as a promising strategy toward improving adsorbent lifetime. Although there is a growing body of work demonstrating the effectiveness of this approach and investigating the origin of this improved stability, studies to date have primarily focused on branched aminopolymer systems such as branched poly(ethylenimine). In this work, hydroxyl-functionalized linear poly(ethylenimine) is used to continue to probe the underlying protective mechanism of this strategy. A combination of thermogravimetric analysis, NMR relaxometry, differential scanning calorimetry, and computational simulations is used to better understand the relationship between the extent of chemical functionalization, physical properties, and adsorbent performance.

amine-based adsorbent↗
DOE OSTI2025

Selection of solvents for integrated CO 2 absorption and electrochemical reduction systems

Abstract Solvent‐based electrochemical CO 2 reduction (CO 2 R) enables the production of chemicals or fuels using CO 2 from a preceding absorption process. Employing previously tested CO 2 capture solvents does not ensure their suitability for either CO 2 R or integrated CO 2 absorption‐reduction. We propose solvent selection criteria that include the CO 2 solubility, kinetic constant, ionic conductivity, concentration of the bicarbonate, carbamate, and solvent cation in the CO 2 ‐loaded solution, and sustainability indicators. They are implemented for solvent selection (a) from novel, aqueous mixtures of N ‐methylcyclohexylamine (MCA) with piperazine (PZ), 2‐amino‐2‐methyl‐1‐propanol (AMP), potassium hydroxide (KOH), and potassium chloride (KCl) and (b) from aqueous monoethanolamine (MEA), AMP, KOH, MCA, and PZ solutions. Versions of a modified Kent‐Eisenberg model for strong bases, carbamate, and non‐carbamate‐forming amine solutions are developed and parameterized through experimental equilibrium measurements. CO 2 R experimental results are presented for solutions of KOH and MCA + KOH, as these indicate desired trade‐offs for CO 2 absorption and reduction.

Amines↗
DOE OSTI2015

The Synthesis, Characterization and Dehydrogenation of Sigma-Complexes of BN-Cyclohexanes

The coordination chemistry of the 1,2-BN-cyclohexanes 2,2-R 2 -1,2-B,N-C 4 H 10 (R 2 =HH, MeH, Me 2 ) with Ir and Rh metal fragments has been studied. This led to the solution (NMR spectroscopy) and solid-state (X-ray diffraction) characterization of [Ir(PCy 3 ) 2 (H) 2 (η 2 η 2 -H 2 BNR 2 C 4 H 8 )][BAr F 4 ] (NR 2 =NH 2 , NMeH) and [Rh( i Pr 2 PCH 2 CH 2 CH 2 P i Pr 2 )(η 2 η 2 -H 2 BNR 2 C 4 H 8 )][BAr F 4 ] (NR 2 =NH 2 , NMeH, NMe 2 ). For NR 2 =NH 2 subsequent metal-promoted, dehydrocoupling shows the eventual formation of the cyclic tricyclic borazine [BNC 4 H 8 ] 3 , via amino-borane and, tentatively characterized using DFT/GIAO chemical shift calculations, cycloborazane intermediates. For NR 2 =NMeH the final product is the cyclic amino-borane HBNMeC 4 H 8 . The mechanism of dehydrogenation of 2,2-H,Me-1,2-B,N-C 4 H 10 using the {Rh( i Pr 2 PCH 2 CH 2 CH 2 P i Pr 2 )} + catalyst has been probed. Catalytic experiments indicate the rapid formation of a dimeric species, [Rh 2 ( i Pr 2 PCH 2 CH 2 CH 2 P i Pr 2 ) 2 H 5 ][BAr F 4 ]. Using the initial rate method starting from this dimer, a first-order relationship to [amine-borane], but half-order to [Rh] is established, which is suggested to be due to a rapid dimer–monomer equilibrium operating.

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

Amphilic Water-Lean Carbon Capture Solvent Wetting Behavior through Decomposition by Stainless-Steel Interfaces

In this work, we report on a combined experimental and theoretical study of the wetting and reactivity of water-lean carbon capture solvents on the surface of common column packing materials. Paradoxically, we find that these solvents are equally able to wet hydrophobic and hydrophilic surfaces. The solvents are amphiphilic and are able to adapt to any interfacial environment due to their inherent heterogeneous molecular structure. Ab initio molecular dynamics indicates that these structures enable the formation of a strong adlayer on the surface of hydrophilic surfaces like oxidized steel which promotes solvent decomposition akin to hydrolysis from surface oxides and hydroxides. This decomposition passivates the surface, making it effectively hydrophobic, and the decomposed solvent promotes leaching of the iron into the bulk fluid. This study links the wetting behavior to the observed corrosion of the steels via decomposition of solvent at steel interfaces. The overall affect is strongly dependent on the chemical composition of the solvent, in that amines are stable, whereas imines and alcohols are not. We also observed that plastic packing shows little to no solvent degradation, but an equal degree of wetting.

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

Biocatalytic Carboxylic Acid Reduction and Transamination in Cell‐Free Lysates at High Substrate Loading

Chemoselective reduction of stable carboxylic acids to reactive aldehydes is of interest across many industries. While carboxylic acid reductases (CARs) are promising biocatalysts for this chemistry, poor chemoselectivity and low yield are commonly obtained when using less expensive crude lysate preparations and prerequisite ATP and NADPH regeneration systems. Here, in this work, we developed a highly chemoselective multienzyme cascade featuring a CAR and an ω-transaminase (TA) in crude lysate format, with conversion of the dicarboxylic acid terephthalic acid (TPA) into the diamine para -xylylenediamine (pXDA) as the model chemistry. We improved chemoselectivity for pXDA using engineered aldehyde-stabilizing Escherichia coli strains, though desired product yields remained modest. We next found that CAR activity was limited at high substrate loadings and overcame this bottleneck by modulating the ratio of polyphosphate (polyP 6 ) to Mg 2+ , enabling volumetric scaling and increased substrate loading up to 50 mM TPA. We then showcased the portability of this platform across substrates, resulting in the synthesis of four other high-value amines from carboxylate precursors. The combination of high carboxyl group turnover, up to 93.5 mM under the tested conditions, and the simplicity of crude enzyme preparation is a promising platform for sustainable functional group interconversion.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2022

Directly Spun Epoxy-Crosslinked Polyethylenimine Fiber Sorbents for Direct Air Capture and Postcombustion Capture of CO 2

A novel, directly injected solid fiber sorbent is synthesized from a solvent-stable, epoxy-crosslinked basic immobilized amine sorbent (BIAS) for CO 2 capture. Leach resistance of the BIAS organics toward 1-methyl-2-pyrrolidone/H 2 O (90/10, fiber solvent) reaches near 100% at the expense of CO 2 capture and is achieved by increasing the extent of crosslinking. The optimized fiber sorbent, prepared with an N,N-diglycidyl-4-glycidyloxyaniline/polyethylenimine (PEI)-0.35/1 wt. ratio, retains 79.2% of PEI and captures 0.37 (direct air capture [DAC]) and 0.67 (postcombustion) mmol CO 2 g-fiber -1 . A nonoptimized prototype hollow fiber exhibits a stable 0.2 mmol CO 2 g-fiber -1 during DAC cycling and is assembled into a ten-fiber module. In conclusion, these results demonstrate a large step toward practical application of this material.

42 ENGINEERING↗
DOE OSTI2018

Synthesis, Photophysical Properties and Application of New Porphyrin Derivatives for Use in Photodynamic Therapy and Cell Imaging

New derivatives of tetrakis(4-carboxyphenyl) porphyrin were designed, synthesized and characterized by IR, proton NMR and mass spectroscopy. The ground and excited state nature of new derivatives were examined using UV-Vis. absorption and fluorescence spectroscopy, fluorescence quantum yield and fluorescence lifetime studies. The singlet oxygen quantum yield of each synthesized derivative of porphyrin was estimated for their further efficacy as potential photosensitizer in biological studies. The significant photophysical data of all synthesized derivatives was supplementary accessed to examine the cell imaging and cytotoxicity against two cancer cell lines viz. MBA-MD-231 and A375. The fluorescence lifetime, fluorescence quantum yield and efficiency of singlet oxygen generation suggests alkyl amine and alkyl hydrazide linked new porphyrin photosensitizers can be useful for PDT agent in cancer treatment.

74 ATOMIC AND MOLECULAR PHYSICS↗
DOE OSTI2018

Development of Biocomposites from Agro Wastes for Low Dielectric Applications

The present work is attempting to synthesize and characterizations of a novel carbazole core containing cardanol based benzoxazine monomer from carbazole core containing aromatic diamine, cardanol and paraformaldehyde. In addition, carbazole core containing cardanol based benzoxazine polymer and various weight percentages of amine functionalized rice husk ash incorporated carbazole core containing cardanol based polybenzoxazine composites were prepared. The prepared polymer and its composites were characterized by FTIR, XRD, DSC, TGA and dielectric studies. The various studies confirm that the composites show increased Tg, higher char yield and better thermal stability compared to carbazole core containing cardanol based benzoxazine polymer. In addition to that the composites show significant decrease in the dielectric constant values than the neat cardanol based polybenzoxazine. The surface morphology and the distribution of rice husk ash in carbazole core containing cardanol based polybenzoxazine composites are confirmed by SEM and TEM analysis. Hence, the present study has attempted to prepared eco-friendly value added carbazole core containing cardanol based polybenzoxazine products for low dielectric constant applications by making use of biowaste for both matrix and reinforcement preparation to form biowaste based composites. Graphical Abstract: Schematic representation for the preparation of carbazole core containing cardanol based benzoxazine monomer, polybenzoxazine and biobased polybenzoxazine composites .

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2019

Autoxidized Oleic Acid Bifunctional Macro Peroxide Initiators for Free Radical and Condensation Polymerization. Synthesis and Characterization of Multiblock Copolymers

Autoxidation of unsaturated fatty acids gives fatty acid macroperoxide initiators containing two functionalities which can lead to free radical and condensation polymerizations in a single pot. The oleic acid macroperoxide initiator obtained by ecofriendly autoxidation (Pole4m) was used in both the free radical polymerization of styrene and the condensation polymerization with amine-terminated polyethylene glycol (PEGNH2) to obtain triblock branched graft copolymers. The narrow molar masses of the poly oleic acid-g-styrene (PoleS) and poly oleic acid-g-styrene-g-PEG (PoSG) graft copolymers were successfully obtained. The inclusion of oleic acid decreased the glass transition temperature of the polystyrene segment because of the plasticizing effect of oleic acid. In addition, a mechanical property of the copolymer was improved when compared with the pure PS. Structural characterization, morphology of the fracture surface, micelle formation, thermal analysis and molar masses of the obtained products were also evaluated.

36 MATERIALS SCIENCE↗
DOE OSTI2012

Synthesis and Evaluation of Conformationally Restricted N4-Tetradentate Ligands for Implementation in An(III)/Ln(III) Separations

The previous literature demonstrates that donor atoms softer than oxygen are effective for separating trivalent lanthanides (Ln(III)) from trivalent actinides (An(III)) (Nash, K.L., in: Gschneider, K.A. Jr., et al. (eds.) Handbook on the Physics and Chemistry of Rare Earths, vol. 18-Lanthanides/Actinides Chemistry, pp. 197-238. Elsevier Science, Amsterdam, 1994). It has also been shown that ligands that 'restrict' their donor groups in a favorable geometry, appropriate to the steric demands of the cation, have an increased binding affinity. A series of tetradentate nitrogen containing ligands have been synthesized with increased steric 'limits'. The pK a values for these ligands have been determined using potentiometric titration methods and the formation of the colored copper(II) complex has been used as a method to determine ligand partitioning between the organic and aqueous phases. The results for the 2-methylpyridyl-substituted amine ligands are encouraging, but the results for the 2-methylpyridyl-substituted diimines indicate that these ligands are unsuitable for implementation in a solvent extraction system due to hydrolysis.

99 GENERAL AND MISCELLANEOUS↗
DOE OSTI2017

Cobalt and manganese complexes with redox-active ligands in polymerization of acrylonitrile and methyl methacrylate

The influence of bis[4,6-di-tert-butyl-N-(2,6-dimethylphenyl)-o-iminobenzosemiquinonato]cobalt(II) and 4,6-di-tert-butyl-N-(2,6-diisopropylphenyl)-o-iminobenzosemiquinonato]-[4,6-di-tert-butyl-N-(2,6-diisopropylphenyl)-o-amidophenolate]manganese(III) on polymerization of methyl methacrylate and acrylonitrile in the presence of azobisisobutyronitrile (as a traditional radical initiator) and alkyl halides (used for initiation of controlled atom transfer radical polymerization process) was studied. The effect of the nature of the activating agents (amines) and the temperature conditions on the overall polymerization rate of the indicated monomers, as well as molecular weight characteristics of the synthesized polymers, were analyzed. The optimal conditions for the synthesis of polyacrylonitrile and poly(methyl methacrylate) with a relatively narrow molecular weight distribution were selected.

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

Biological activity of some sulfur- and selenium-containing spiro compounds

Cytotoxicity to K-562 leukemia cell line of two spiro compounds containing selenium or sulfur atom in their structure were compared. 4-Fluorophenyl-(1-thia-3-azaspiro[5.5]undec-2-en-2-yl]amine hydrobromide was synthesized and characterized for the first time. It was found that the introduction of a sulfur atom is more promising for this biological model, since it leads to a 3-fold increase in the therapeutic index in the case of the sulfur-containing compound.

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

Novel representatives of 16-membered aminomethylphosphines with alkyl substituents at nitrogen and their gold(I) complexes

Novel 1,9-diaza-3,7,11,15-tetraphosphacyclohexadecanes with alkyl, arylalkyl, or heteroarylalkyl substituents at the endocyclic nitrogen atoms were synthesized by condensation of 1,3-bis(phenylphosphino)propane, formaldehyde, and primary amines. The reactions are stereoselective and result in the isomer with the RSSR configuration of the phosphorus atoms as the major product. The 16-membered tetrakis(phosphine) ligands form stable neutral tetranuclear complexes with gold(I). In these complexes, the 16-membered cyclic ligands retain their free-state conformations and the configuration of the chiral phosphorus atoms.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2019

Stereoinversion in the diastereoselective acylation of benzoxazine derivatives with 2-aryloxypropionyl chlorides

A comparative study of the kinetic resolution of racemic derivatives of 3,4-dihydro-3-methyl-2H-[1,4]benzoxazine using racemic 2-aryloxypropionyl chlorides was performed. It was found that the acylation of racemic amines with racemic 2-(1-naphthyloxy)propionyl chloride leads to amides enriched with (3R*,2′R*)-diastereomers, while the acylation with 2-phenoxypropionyl chloride gives predominantly (3R*,2′S*)-amides. Quantum chemical modeling of the process of kinetic resolution at the COSMO-CH{sub 2}Cl{sub 2}-B3LYP-D3-gCP/def2-TZVP//B3LYP-D3-gCP/def2-SVP level of theory was performed. The computational results are in a good agreement with the experimental data.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2019

Bisdiamidophosphite with a bisoxazoline moiety in palladium-catalyzed enantioselective allylation

A bisdiamidophosphite ligand with stereogenic phosphorus atoms as a part of 1,3,2-diaza-phospholidine rings and a bisoxazoline backbone was synthesized and studied in the Pd-catalyzed asymmetric allylic substitution. The use of this ligand provided up to 93% ee in the alkylation of (E)-1,3-diphenylallyl acetate with dimethyl malonate and up to 77% ee in the amination with pyrrolidine at quantitative conversion of the starting substrate.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗