Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “ketones”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
NASA NTRS1995

Prepsolv (TM): The optimum alternative to 1,1,1-trichloroethane and methyl ethyl ketone for hand-wipe cleaning of aerospace materials

Engineers at Hercules Aerospace, a rocket motor manufacturer in Utah, have worked closely with chemists at Glidco Organics to study the feasibility of using terpenes for zero-residue wipe cleaning. The result of this work is a technological breakthrough, in which the barrier to ultra-low non-volatile residue formation has been broken. After 2 years of development and testing, SCM Glidco Organics has announced the availability of Glidsafe(registered trademark) Prepsolv(TM): a state-of-the-art ultra-low residue terpene wipe cleaning agent that does not require rinsing. Prepsolv(TM) can successfully be used in simple hand-wipe cleaning processes without fear of leaving surface residues. Industry testing has confirmed that Prepsolv(TM) is not only highly effective, but can even be less expensive to use than traditional cleaning solvents like methyl chloroform. This paper addresses the features and benefits of Prepsolv(TM), and presents performance and material compatibility data that characterizes this unique cleaning agent. Since its commercialization, Hercules Aerospace has chosen Prepsolv(TM) as the optimum cleaning agent to replace ozone-depleting solvents in their weapons factory in Magna, UT. Likewise, Boeing has approved Prepsolv(TM) for cleaning components in the manufacture of commercial aircraft at their facilities in Seattle, WA and Wichita, KS. Additional approvals are forthcoming for this uniquely safe and effective solvent.

Gallagher, R. Scott↗
NASA NTRSDate not supplied

Multiscale Modeling of Thermoplastics Using Atomistic-informed Micromechanics

A multiscale model was developed for predicting the thermoelastic behavior of semi-crystalline thermoplastic materials for composite aerospace applications. At the highest scale containing the semi-crystalline spherulite in an amorphous matrix, the generalized method of cells, or high fidelity method of cells, was used to perform the homogenization calculations to obtain the effective properties. Models were developed assuming a cubic, or spherical shape, for the spherulite to understand if the morphology of the spherulite affects the effective thermoelastic properties. The generalized method of cells was used to model at the repeating unit cells at the subscales of the microstructure including the lamellae stacks and granular crystal blocks. The scales are integrated using the multiscale micromechanics method in the NASA Multiscale Analysis Tool. Data from molecular dynamics simulations were used as inputs for the amorphous and crystalline constituents. Convergence studies were performed to determine the best level of discretization for the repeating unit cell at the highest scale. Effective Young’s modulus, shear modulus, Poisson’s ratio, coefficient of thermal expansion, and thermal conductivity were predicted for polyether ether ketone and polyether ketone ketone, and very good agreement between the model utilizing the cubic spherulite and the experimental data, where available, was observed for polyether ketone ketone. Normalization of the data for the bulk polyether ketone ketone, against amorphous data, improved the predictions as compared to experimental data. Overall, the high fidelity method of cells predicted a stiffer response then the generalized method of cells as the crystallinity was increased. The shape of the spherulite had a minimal effect on the predicted bulk properties of the polymers.

thermoplastics↗
NASA NTRS1988

Polyenamines from aromatic diacetylenic diketones and diamines

The synthesis and characterization of several ployenamine ketones are discussed wherein conjugated diacetylenic diketones and aromatic diamines are used as a route to the formation of high molecular weight polyenamine ketones which exhibit good mechanical properties and can be cast into creasible films. Typical polymerization conditions involved the reaction of stoichiometric amounts of 1,4- or 1,3-PPPO and a diamine at 60°-130° C. in m-cresol at (w/w) solids content of 8-26% for a specified period of time under a nitrogen atmosphere. Novel polyenamine ketones were prepared with inherent viscosities as high as 1.99 dl/g and tough, clear amber films with tensile strengths of 12,400 psi and tensile moduli of 397,000 psi were cast from solutions of the polymers in chloroform. The polymers exhibited T g s as high as 235° C. and weight losses of 14% after aging at 232° C. in circulating air for sixty hours. The specific conditions for the preparation of the various polyenamine ketones are presented in Table I. In most cases, the elemental analyses for the polyenamine ketones, shown in Table II, agree within ±0.3% of the theoretical values.

Paul M Hergenrother↗
DOE OSTI2025

Electronic and reactivity changes in epitaxially grown Ce 1-x Zr x O 2-δ (111) thin films

Ceria composite catalysts have long been used for ketonization reactions, which is a valuable chemistry for the upgrading of biomass-derived carboxylates. To better understand the interaction of zirconia with ceria in the context of ketonization, thin epitaxial films of ceria-zirconia mixed metal oxide Ce 1-x Zr x O 2-δ (x = 0-1) were grown on a Pt(111) substrate in ultrahigh vacuum conditions and studied with X-ray photoelectron spectroscopy (XPS). Core level and valence band XPS results suggest a strong interaction between ceria and zirconia cations, possibly due to increased filling of unoccupied 4f 0 orbitals of ceria from neighboring Zr cations in the lattice structure. This leads to a partial reduction of ceria from Ce 4+ to Ce 3+ , with Zr remaining predominantly in the 4+ oxidation state. Ketonization of acetic acid was studied using temperature programmed desorption (TPD) and high-resolution electron energy loss spectroscopy (HREELS). These results found ketonization over mixed Ce-Zr composite oxides exhibited lower activation energies than for pure CeO 2 and ZrO 2 , with Ce 0.38 Zr 0.62 O 2-δ exhibiting the highest yield of acetone among the studied surfaces. In conclusion, these results suggest the high activity of Ce-Zr catalysts appears to be a result of oxygen vacancy formation, stabilized by electron donation from Zr cations.

36 MATERIALS SCIENCE↗
NASA NTRS1987

Polyenamines from aromatic diacetylenic diketones and diamines

The synthesis and characterization of several polyenamine ketones are discussed wherein conjugated diacetylenic diketones and aromatic diamines are used as a route to the formation of high molecular weight polyenamine ketones which exhibit good mechanical properties and can be cast into creasible films. Typical polymerization conditions involved the reaction of stoichiometric amounts of 1,4- or 1,3-PPPO and a diamine at 60 to 130 C in m-cresol at (w/w) solids content of 8 to 26% for a specified period of time under a nitrogen atmosphere. Novel polyenamine ketones were prepared with inherent viscosities as high as 1.99 dl/g and tough, clear amber films with tensile strengths of 12,400 psi and tensile moduli of 397,000 psi were cast from solutions of the polymers in chloroform. In most cases, the elemental analyses for the polyenamine ketones agree within + or - 0.3% of the theoretical values.

Hergenrother, Paul M.↗
NASA NTRS1991

Evaluation of the Strecker synthesis as a source of amino acids on carbonaceous chondrites

The Strecker synthesis (SS) has been proposed as the source of amino acids (AA) formed during aqueous alteration of carbonaceous chondrites. It is postulated that the aldehyde and ketone precursors of the meteoritic AA originated in interstellar syntheses and accreted on the meteorite parent body along with other reactant species in cometesimal ices. The SS has been run with formaldehyde, acetyldehyde, propionaldehyde, acetone, and methyl ketone as starting materials. To study the effect of minerals on the reaction, the SS was run in the presence and absence of dust from the Allende meteorite using deuterated aldehydes and ketones as starting materials. The products were studied by GC/MS. With the exception of glycine, the retention of deuterium in the AA was greater than 90 pct. Some D exchange with water does occur, however, and determination of the rate of exchange as a function of pH and temperature may allow some bounds to be placed on the duration of parent body aqueous alteration. The retention of D by the AA under conditions studied thus far is consistent with the model that a SS starting from interstellar aldehydes and ketones led to the production of meteoritic AA.

Lerner, N. R.↗
NASA NTRS2004

Diels-Alder Trapping of Photochemically Generated o-Quinodimethane Intermediates: An Alternative Route to Photocured Polymer Film Development

Photolysis of o-methylphenyl ketones generates bis-o-quinodimethane intermediates that can be trapped in situ by dienophiles through Diels-Alder cycloadditions. This well-known photochemical process is applied to a series of six new photoreactive monomers containing bis-(o-methylphenyl ketone) functionalities combined with diacrylate and triacrylate ester monomers for the development of acrylic ester copolymer blends. Irradiation of cyclohexanone solutions of the bis-(o-methylphenyl ketone)s and acrylate esters produce thin polymer films. Solid state 13C NMR data indicated 47- 100% reaction of the bis-(o-methylphenyl ketone)s, depending on experimental conditions, to yield the desired products. DSC and TGA analyses were performed to determine the glass transition temperature, T,, and onset of decomposition, Td, of the resulting polymer films. A statistical Design of Experiments approach was used to obtain a systematic understanding of the effects of experimental variables on the extent of polymerization and the final polymer properties.

Tyson, Daniel S.↗
NASA NTRS2023

Manufacturing and Mechanical Testing of TC1225/LM-PAEK and TC1200/PEEK Thermoplastic Composite Panels

Development of thermoplastic composites (TPCs) for aerospace structures is experiencing renewed enthusiasm attributed to the availability of rapid manufacturing technology, ease of joining through fusion welding processes, and the successful utilization of the material in flight critical structures. Semicrystalline thermoplastics such as polyether ether ketone (PEEK), polyether ketone ketone (PEKK), and polyphenylene sulfide (PPS) have been successfully demonstrated as thermoplastic skins, keel beams, and angle brackets for commercial aircraft. Composite specimens were fabricated from the Toray TC1225 and TC1200 unidirectional prepreg systems and tested to gain confidence with NASA in-house TPC processing as part of the Thermoplastics Development for Exploration Application (TDEA) project. TC1225 is a relatively new material system that uses T700GC fibers and low-melt polyaryl ether ketone (LM-PAEK) resin. TC1200 is the latest version of a material system that has been available for several decades with AS4 fibers and PEEK resin. Results for ultrasonic inspection, optical microscopy, acid digestion, and differential scanning calorimetry establish the quality of the panels. Mechanical test data for unnotched and notched laminate tension and compression as well as compression after impact provide data for equivalency assessment and support material selection in TDEA. Satisfactory equivalence of the TC1225 results and the National Center for Advanced Materials Performance (NCAMP) database was found. The results indicate high-quality manufacturing was achieved, and the resulting mechanical test data are in agreement with that in the literature.

Thermoplastic Composites↗
DOE OSTI2026

Mechanism of O 2 /NO-Promoted Oxidative C–C Bond Cleavage in Linear Alkanes

Selective oxidation of alkanes to oxygenated products remains a fundamental challenge, particularly if the goal is to promote C−C bond cleavage while minimizing formation of CO 2 . Oxidation conditions that use O 2 and nitrogen oxides (NO x ) have been shown to be very effective in promoting radical-mediated functionalization and oxidative carbon−carbon cleavage in saturated hydrocarbon polymers, such as polyethylene. Here, we investigate the mechanism of O 2 /NO-mediated oxidation of ndecane as a prototypical linear alkane substrate. These reactions enable identification and quantification of reactive intermediates, including nitrites, nitrates, alcohols, and ketones. Under the reaction conditions, these species convert into common ketone intermediates that evolve into α-diketones and other α-functionalized ketones, which undergo further conversion into carboxylic acids. Infrared (IR) spectroscopy indicates that HDPE oxidation proceeds through similar key intermediates. Together, these findings establish a mechanistic framework for NO x -mediated alkane oxidation and provide a foundation for the development of broadly applicable oxidative transformations.

Anions↗
DOE OSTI2024

Copper‐Catalyzed C(sp 3 )−H α‐Acetylation: Generation of Quaternary Centers

Abstract α‐substituted ketones are important chemical targets as synthetic intermediates as well as functionalities in natural products and pharmaceuticals. We report the α‐acetylation of C(sp 3 )−H substrates R−H with arylmethyl ketones ArC(O)Me to provide α‐alkylated ketones ArC(O)CH 2 R at RT with t BuOO t Bu as oxidant via copper(I) ‐diketiminato catalysts. Proceeding via alkyl radicals R•, this method enables α‐substitution with bulky substituents without competing elimination that occurs in more traditional alkylation reactions between enolates and alkyl electrophiles. DFT studies suggest the intermediacy of copper(II) enolates [Cu II ](CH 2 C(O)Ar) that capture alkyl radicals R• to give R−CH 2 C(O)Ar outcompeting dimerization of the copper(II) enolate to give the 1,4‐diketone ArC(O)CH 2 CH 2 C(O)Ar.

Okoromoba, Otome E.↗
DOE OSTI2024

Copper‐Catalyzed C(sp 3 )−H α‐Acetylation: Generation of Quaternary Centers

Abstract α‐substituted ketones are important chemical targets as synthetic intermediates as well as functionalities in natural products and pharmaceuticals. We report the α‐acetylation of C(sp 3 )−H substrates R−H with arylmethyl ketones ArC(O)Me to provide α‐alkylated ketones ArC(O)CH 2 R at RT with t BuOO t Bu as oxidant via copper(I) ‐diketiminato catalysts. Proceeding via alkyl radicals R•, this method enables α‐substitution with bulky substituents without competing elimination that occurs in more traditional alkylation reactions between enolates and alkyl electrophiles. DFT studies suggest the intermediacy of copper(II) enolates [Cu II ](CH 2 C(O)Ar) that capture alkyl radicals R• to give R−CH 2 C(O)Ar outcompeting dimerization of the copper(II) enolate to give the 1,4‐diketone ArC(O)CH 2 CH 2 C(O)Ar.

Okoromoba, Otome E.↗
DOE OSTI2025

Oxidation of n-alkanes using TS-1 and H 2 O 2 : Effects of chain length and solvents

The selective oxidation of n-C 8 H 18 , n-C 12 H 26 , n-C 16 H 34 , n-C 20 H 42 , and n-C 36 H 74 was studied with a goal of using these as models to provide insight into how to functionalize polyolefins. Reactions were carried out using a TS-1 catalyst and H 2 O 2 in a batch reactor with different cosolvents, including methanol, acetone, acetonitrile, methyl ethyl ketone, and methyl butyl ketone. Rates decreased with increasing alkane size, possibly due to the reduced solubility of larger alkanes into the water-rich phases. Cosolvents that promote the partitioning of alkanes in the aqueous phase increased the rates. 1 H NMR spectroscopy demonstrated that ketones were the primary products, although some alcohols also formed. There was preferential reaction at the 2 position in the alkanes, but reaction at central carbons was also observed. The results of this study suggest strategies for using this catalytic chemistry to functionalize polyolefins.

Alkane oxidation↗
DOE OSTI2025

Data for Metabolic Engineering of β-Oxidation to Leverage Thioesterases for Production of 2-Heptanone, 2-Nonanone, and 2-Undecanone

Medium-chain length methyl ketones are potential blending fuels due to their cetane numbers and low melting temperatures. Biomanufacturing offers the potential to produce these molecules from renewable resources such as lignocellulosic biomass. In this work, we designed and tested metabolic pathways in Escherichia coli to specifically produce 2-heptanone, 2-nonanone and 2-undecanone. We achieved substantial production of each ketone by introducing chain-length specific acyl-ACP thioesterases, blocking the β-oxidation cycle at an advantageous reaction, and introducing active β-ketoacyl-CoA thioesterases. Using a bioprospecting approach, we identified 15 homologs of E. coli β-ketoacyl-CoA thioesterase (FadM) and evaluated the in vivo activity of each against various chain length substrates. The FadM variant from Providencia sneebia produced the most 2-heptanone, 2-nonanone, and 2-undecanone, suggesting it has the highest activity on the corresponding β-ketoacyl-CoA substrates. We tested enzyme variants, including acyl-CoA oxidases, thiolases, and bi-functional 3-hydroxyacyl-CoA dehydratases to maximize conversion of fatty acids to β-keto acyl-CoAs for 2-heptanone, 2-nonanone, and 2-undecanone production. In order to address the issue of product loss during fermentation, we applied a 20% (v/v) dodecane layer in the bioreactor and built an external water cooling condenser connecting to the bioreactor heat-transferring condenser coupling to the condenser. Using these modifications, we were able to generate up to 4.4 g/L total medium-chain length methyl ketones.

Metabolic Engineering↗
NASA NTRS1987

The 2.5-diacyl-1,4-dimethylbenzenes: Examples of bisphotoenol equivalents

The photochemistry of 2,5-dibenzoyl(DBX)-and 2,5-diacetyl-1,4-dimethylbenzene (DAX) has been investigated. Both compounds readily undergo photoenolization similar to 0-alkylphenyl ketones. However, unlike 0-alkylphenyl ketones DAX and DBX are each capable of undergoing two tandem photoenolizations. Photoenols derived from o-alkylphenyl ketones have been successfully trapped with Diels-Alder dienophiles to provide a convenient synthesis of substituted tetralins. Similarly, Diels-Alder trapping of DBX photoenils afforded substituted tetra- and octahydro anthracenes. Further mainpulation of these photadducts provided the corresponding anthracenes in good yield. The photochemistry of DAX and DBX will be discussed, in particular their use in the synthesis of substituted anthracenes.

Meador, Michael A.↗
NASA NTRS2024

Multiscale Modeling of Thermoplastics Using Atomistic-informed Micromechanics

A multiscale repeating unit cell model of a single spherulite containing four disparate length scales was developed to predict the thermoelastic behavior of semicrystalline thermoplastic materials for composite aerospace applications. The continuum level scales were fully coupled and modeled using the generalized method of cells and the high fidelity generalized method of cells micromechanics theories. Data from molecular dynamics simulations were used as inputs for the amorphous and crystalline constituents in the multiscale continuum models. Effective Young’s modulus, shear modulus, Poisson’s ratio, coefficient of thermal expansion, and thermal conductivity were predicted for polyether ether ketone and polyether ketone ketone, showing good agreement with the available experimental data from the open literature. Moreover, it is shown that predicted properties are fairly insensitive to the fidelity of the micromechanics model used at the highest continuum scale or the assumed shape of the spherulite.

thermoplastics↗
DOE OSTI2026

Cost-effective valorization of 2,3-butanediol to high-value chemicals and jet fuel

Here, this work outlines an optimized process for converting 2,3-butanediol (BDO) into sustainable aviation fuel (SAF) and C4 chemicals. BDO is reactively separated from fermentation broth by forming dioxolanes, which are converted to isobutyraldehyde, methyl ethyl ketone (MEK), and 1,3-butadiene. These intermediates are reduced and dehydrated over Cu/ZSM-5 to form alkenes, which can be oligomerized and hydrotreated to jet-range alkanes. Previous BDO-dioxolane-alkene processes are limited by the requirement for a continuous aldehyde source for dioxolane formation. Brønsted acidic zeolites catalyze dioxolane deacetalization to form isobutyraldehyde and MEK in a >2:1 molar ratio, providing an internal, recyclable aldehyde source. Dioxolane formation optimization was performed to achieve >95% dioxolane yields over Amberlyst-15 and minimize isobutyraldehyde recycle. The overall BDO-dioxolane-fuel process yields an alkane mixture that enables at least a 50% v/v blend with Jet-A. Techno-economic analyses and life cycle assessments for this BDO-dioxolane-fuel process yield scenarios with <$2.50 per gallon gas equivalent and >58% reduction in CO2 emissions.

2,3-butanediol↗
DOE OSTI2026

Trace gases at TRACER ANC site

Speciated volatile organic compounds (VOCs) were measured using an Ionicon PTR-TOF 8000 from 20 June to 3 July 2022 at the TRACER ancillary (TRACER ANC) site in Guy, TX. The dataset is reported at 1-min time resolution. Mixing ratios (ppb) are provided for acetone, methanol, acetaldehyde, dimethyl sulfide (DMS), furan, isoprene, methyl vinyl ketone plus methyl ethyl ketone (MVK + MEK), terpenes, xylene, and trimethylbenzene. Instrument calibrations for these species were performed weekly using a certified gas standard.

acetaldehyde↗