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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 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1993

Measurements of nitric acid, carboxylic acids, and selected aerosol species for the NASA/GTE Pacific Mission - West (PEM-WEST)

The research investigation funded through this grant to the University of New Hampshire was performed during a major field expedition conducted by the NASA Tropospheric Chemistry Program. The NASA Global Tropospheric Experiment (GTE) executed an airborne science mission (PEM-WEST A) aboard the NASA Ames DC-8 over the Pacific Ocean during Sep./Oct. 1981. The atmosphere over the central Pacific Ocean is the only major region in the Northern Hemisphere that is relatively free from direct anthropogenic influence. Thus, this environment is ideally suited to study the natural biogeochemical cycles of carbon, nitrogen, ozone, sulfur, and aerosols without serious confounding problems related to anthropogenic emissions. Asian sources account for about 17 percent of the global budgets of nitrogen oxides (NO(x)) and sulfur dioxide (SO2). The Pacific Rim region therefore provides the opportunity to study the anthropogenic impact on natural atmospheric chemical cycles. The PEM-WEST A flights were focused on contrasting the chemistry of 'clean' air over the central Pacific with anthropogenically impacted air advected off the Asian continent. The principal objectives of PEM-WEST A were to investigate the atmospheric chemistry of ozone (O3) and its precursors, and to study important aspects of the atmospheric sulfur cycle over the western Pacific Ocean. Measurements conducted by the University of New Hampshire contributed directly to both of these objectives. Subsequent PEM-WEST field missions are planned by GTE in the mid-1990's to contrast atmospheric chemistry documented during PEM-WEST A with other time periods. This report presents preliminary findings from the PEM-WEST A field mission. Data interpretation is currently ongoing with the goal of manuscript submission of scientific results to a special issue of the Journal of Geophysical Research-Atmospheres in Feb. 1994. The reader is strongly encouraged to review this suite of profession articles to appreciate the overall scientific findings and benefits of the PEM-WEST A field mission.

Talbot, Robert W.↗
NASA NTRS2023

Formation of Amino Acids and Carboxylic Acids in Weakly Reducing Planetary Atmospheres by Solar Energetic Particles from the Young Sun

Life most likely started during the Hadean Eon; however, the environmental conditions which contributed to the complexity of its chemistry are poorly known. A better understanding of various environmental conditions, including global (heliospheric) and local (atmospheric, surface, and oceanic), along with the internal dynamic conditions of the early Earth, are required to understand the onset of abiogenesis. Herein, we examine the contributions of galactic cosmic rays (GCRs) and solar energetic particles (SEPs) associated with superflares from the young Sun to the formation of amino acids and carboxylic acids in weakly reduced gas mixtures representing the early Earth’s atmosphere. We also compare the products with those introduced by lightning events and solar ultraviolet light (UV). In a series of laboratory experiments, we detected and characterized the formation of amino acids and carboxylic acids via proton irradiation of a mixture of carbon dioxide, methane, nitrogen, and water in various mixing ratios. These experiments show the detection of amino acids after acid hydrolysis when 0.5% (v/v) of initial methane was introduced to the gas mixture. In the set of experiments with spark discharges (simulation of lightning flashes) performed for the same gas mixture, we found that at least 15% methane was required to detect the formation of amino acids, and no amino acids were detected in experiments via UV irradiation, even when 50% methane was used. Carboxylic acids were formed in non-reducing gas mixtures (0% methane) by proton irradiation and spark discharges. Hence, we suggest that GCRs and SEP events from the young Sun represent the most effective energy sources for the prebiotic formation of biologically important organic compounds from weakly reducing atmospheres. Since the energy flux of space weather, which generated frequent SEPs from the young Sun in the first 600 million years after the birth of the solar system, was expected to be much greater than that of GCRs, we conclude that SEP-driven energetic protons are the most promising energy sources for the prebiotic production of bioorganic compounds in the atmosphere of the Hadean Earth.

Kensei Kobayashi↗
DOE OSTI2023

Synthesis of Acid Hydrazides from Carboxylic Acids in Continuous Flow

A concise methodology for the synthesis of acid hydrazides from carboxylic acids via a continuous flow process in yields ranging from 65 to 91% is described. Using short residence times of between 13 and 25 mins, the conditions proved amenable to a variety of mono- and diacids, including aliphatic, aromatic, and heteroaromatic functionalities. Furthermore, to demonstrate scalability, a large-scale (200 g) synthesis of azelaic dihydrazide was conducted over a continuous run of 9 h with an 86% overall yield, equating to a 22 g/h output.

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

Post-Fermentation Recovery of Biobased Carboxylic Acids

Carboxylic acids are common products produced from the bioconversion of renewable feedstocks. In these processes the separation of the acid product from fermentation broth is the most energy and cost intensive unit operation. Thus, the development of robust, scalable separation approaches that can be applied to a variety of carboxylates is of critical importance to the development of processes that utilize carboxylic acids as platform chemicals. Here we report a batch separation method that includes cell and particulate removal, cation exchange, activated carbon treatment, dewatering with a polymer resin, and product recovery. This method is demonstrated on two unique fermentation broths both derived from corn stover hydrolysate to separate neat succinic and propionic acid. For succinic acid, a crystallization yield of 91% with a product purity of 99.93% was achieved. To our knowledge this is the highest reported crystallization yield and purity for the recovery of succinic acid. Additionally, the method requires approximately 50% less energy compared to standard evaporative crystallization approaches. For propionic acid, neat liquid product was obtained with a distillation yield of 80% and purity of 98%. Finally, these excellent results achieved in terms of yield and purity for succinic and propionic acid, two acids with widely different physical properties, from chemically complex hydrolysate broth demonstrates the effective and robust nature of this approach.

09 BIOMASS FUELS↗
DOE OSTI2022

Modeling the Solvation and Acidity of Carboxylic Acids Using an Ab Initio Deep Neural Network Potential

Formic and acetic acid constitute the simplest of carboxylic acids, yet they exhibit fascinating chemistry in the condensed phase such as proton transfer and dimerization. The go-to method of choice for modeling these rare events have been accurate but expensive ab-initio molecular dynamics simulations. Here, we present a deep neural network potential trained using accurate ab-initio data that can be used in tandem with enhanced-sampling methods to perform an efficient exploration of the free-energy surface of aqueous solutions of weak carboxylic acids. In particular, we show that our model captures proton dissociation and provides a good estimate of the pK a , as well as the dimerization of formic and acetic acid. This provides a suitable starting point for applications in different research areas where computational efficiency coupled with the accuracy of ab-initio methods is required.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2020

Direct Oxidation of Primary Alcohols to Carboxylic Acids

Oxidation of primary alcohols to carboxylic acids is a fundamental transformation in organic chemistry, yet despite its simplicity, extensive use, and relationship to pH, it remains a subject of active research for synthetic organic chemists. Since 2013, a great number of new methods have emerged that utilize transition-metal compounds as catalysts for acceptorless dehydrogenation of alcohols to carboxylates. The interest in this reaction is explained by its atom economy, which is in accord with the principles of sustainability and green chemistry. Furthermore, the methods for the direct synthesis of carboxylic acids from alcohols is ripe for a modern survey, which we provide in this review.

acceptorless dehydrogenation↗
NASA NTRS1987

Unusual stable isotope ratios in amino acid and carboxylic acid extracts from the Murchison meteorite

The isotopic composition of hydrogen, nitrogen, and carbon in amino acid and monocarboxylic acid extracts from the Murchison meteorite has been determined. The unusually high D/H and N-15/N-14 ratios in the amino acid fraction are uniquely characteristic of known interstellar organic materials. The delta D value of the monocarboxylic acid fraction is lower but still consistent with an interstellar origin. These results confirm the extraterrestrial origin of both classes of compound and provide the first evidence suggesting a direct relationship between the massive organosynthesis occurring in interstellar clouds and the presence of prebiotic compounds in primitive planetary bodies.

Epstein, S.↗
DOE OSTI2018

Acyl Glucuronide Metabolites of 6-Chloro-5-[4-(1-hydroxycyclobutyl)phenyl]-1 H -indole-3-carboxylic Acid (PF-06409577) and Related Indole-3-carboxylic Acid Derivatives are Direct Activators of Adenosine Monophosphate-Activated Protein Kinase (AMPK)

Studies on indole-3-carboxylic acid derivatives as direct activators of human adenosine monophosphate-activated protein kinase (AMPK) α1β1γ1 isoform have culminated in the identification of PF-06409577 (1), PF-06885249 (2), and PF-06679142 (3) as potential clinical candidates. Compounds 1–3 are primarily cleared in animals and humans via glucuronidation. In this paper, we describe the biosynthetic preparation, purification, and structural characterization of the glucuronide conjugates of 1–3. Spectral characterization of the purified glucuronides M1, M2, and M3 indicated that they were acyl glucuronide derivatives. In vitro pharmacological evaluation revealed that all three acyl glucuronides retained selective activation of β1-containing AMPK isoforms. Inhibition of de novo lipogenesis with representative parent carboxylic acids and their respective acyl glucuronide conjugates in human hepatocytes demonstrated their propensity to activate cellular AMPK. Cocrystallization of the AMPK α1β1γ1 isoform with 1–3 and M1–M3 provided molecular insights into the structural basis for AMPK activation by the glucuronide conjugates.

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

Determining aromatic and aliphatic carboxylic acids in biomass-derived oil samples using 2,4-dinitrophenylhydrazine and liquid chromatography-electrospray injection-mass spectrometry/mass spectrometry

Converting biomass to a useful fuel commonly incorporates the pyrolysis of the biomass feed stock. The base liquid fraction usually contains high concentrations of ketones, aldehydes and carboxylic acids, of which each can cause detrimental issues related to the storage and upgrading process. Knowing the carbonyl species and the concentration of each will provide value information to the pyrolysis researchers, specifically as that community branches into more targeted end-products such as jet fuel or biogenic-derived oxygenate-containing fuel products. The analysis of aldehydes, ketones and small alkyl carboxylic acids using 2,4-dinitrophenylhydrazine (DNPH) derivation method has been well documented and the method is commonly used the analytical community. By using liquid chromatograph coupled to tandem mass spectrometry, biomass sample analysis can be complete with identification of most carbonyl species. The issue of identifying isobaric ketone and aldehyde compounds can be resolved by utilizing differences in retention time or characteristic fragment ions of ketones and aldehydes. One issue which could not resolved using published methods was identifying aromatic or large non-aromatic carboxylic acids from their corresponding hydroxyl aldehyde or ketone analogs. By modifying the current method for determining carbonyls in biomass samples, carboxylic and hydroxyl-carbonyl can be determined. A careful adjustment of the pH during the extraction procedure and extended heating time of the DNPH solution allowed for the successful derivation of aromatic carboxylic acids. Like other dinitrophenylhydrazones, carboxylic acid derivatives also produce a unique secondary ion pattern, which was useful to distinguish these species from the non-acid analogs.

bio-oil↗
DOE OSTI2019

Coarse-Grained Models for Constant pH Simulations of Carboxylic Acids

A model for carboxylic acids, in both the protonated and deprotonated states, is developed in which hydrogen interaction sites are not used and all interactions are short-ranged. A method for constant pH simulations, which exploits these features of the model, is developed. Here, the constant pH method samples protonation states by making discrete Monte Carlo steps and is able to efficiently move between states in two steps. The method is applied to the polymer poly(methacrylic acid), a pH-responsive polymer that undergoes structural changes as a function of pH. The model is able to reproduce the structural changes induced by pH.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2018

Phenazine‐1‐carboxylic acid and soil moisture influence biofilm development and turnover of rhizobacterial biomass on wheat root surfaces

Summary Phenazine‐1‐carboxylic acid (PCA) is produced by rhizobacteria in dryland but not in irrigated wheat fields of the Pacific Northwest, USA. PCA promotes biofilm development in bacterial cultures and bacterial colonization of wheat rhizospheres. However, its impact upon biofilm development has not been demonstrated in the rhizosphere, where biofilms influence terrestrial carbon and nitrogen cycles with ramifications for crop and soil health. Furthermore, the relationships between soil moisture and the rates of PCA biosynthesis and degradation have not been established. In this study, expression of PCA biosynthesis genes was upregulated relative to background transcription, and persistence of PCA was slightly decreased in dryland relative to irrigated wheat rhizospheres. Biofilms in dryland rhizospheres inoculated with the PCA‐producing (PCA + ) strain Pseudomonas synxantha 2‐79RN 10 were more robust than those in rhizospheres inoculated with an isogenic PCA‐deficient (PCA ‐ ) mutant strain. This trend was reversed in irrigated rhizospheres. In dryland PCA + rhizospheres, the turnover of 15 N‐labelled rhizobacterial biomass was slower than in the PCA ‐ and irrigated PCA + treatments, and incorporation of bacterial 15 N into root cell walls was observed in multiple treatments. These results indicate that PCA promotes biofilm development in dryland rhizospheres, and likely influences crop nutrition and soil health in dryland wheat fields.

LeTourneau, Melissa K.↗
DOE OSTI2020

Engineering the cellulolytic extreme thermophile Caldicellulosiruptor bescii to reduce carboxylic acids to alcohols using plant biomass as the energy source

Abstract Caldicellulosiruptor bescii is the most thermophilic cellulolytic organism yet identified (Topt 78 °C). It grows on untreated plant biomass and has an established genetic system thereby making it a promising microbial platform for lignocellulose conversion to bio-products. Here, we investigated the ability of engineered C. bescii to generate alcohols from carboxylic acids. Expression of aldehyde ferredoxin oxidoreductase (aor from Pyrococcus furiosus) and alcohol dehydrogenase (adhA from Thermoanaerobacter sp. X514) enabled C. bescii to generate ethanol from crystalline cellulose and from biomass by reducing the acetate produced by fermentation. Deletion of lactate dehydrogenase in a strain expressing the AOR–Adh pathway increased ethanol production. Engineered strains also converted exogenously supplied organic acids (isobutyrate and n-caproate) to the corresponding alcohol (isobutanol and hexanol) using both crystalline cellulose and switchgrass as sources of reductant for alcohol production. This is the first instance of an acid to alcohol conversion pathway in a cellulolytic microbe.

Biotechnology & Applied Microbiology↗
DOE OSTI2017

Alicyclic carboxylic acids in soil humic acid as detected with ultrahigh resolution mass spectrometry and multi-dimensional NMR

It has been well accepted that humic acids in soils comprise both aromatic and aliphatic structural units that harbor mainly oxygenated functional groups such as carboxylic acids, aldehydes, ketones, and hydroxyl groups. Recent mass spectral data obtained from electrospray ionization-Fourier transform ion cyclotron resonance mass spectrometry (ESI-FTICRMS) suggest that the main functional groups in humic acids are carboxylic acids bound to both alicyclic and condensed aromatic molecules. It was suggested that these structural entities originate from oxidation of lignin. To provide additional support, detailed structural characteristics were obtained here using several multi-dimensional nuclear magnetic resonance (NMR) techniques to observe the molecular connectivity of humic acid components, with a focus on carboxylic acids in particular. The humic acid sample examined had been shown to exhibit structural characteristics similar to a larger set of soil humic acids. Here in this study, many carboxylic acid resonances were found to correlate with protons that could be assigned to aliphatic and alicyclic chemical shift regions. Functional groups with heteroatoms such as alcohols, some olefins and an assortment of methyl groups were found to correlate within 2–3 bonds of carboxylic acid groups. The collection of structural components and their proximity to a variety of carboxylic groups supports the occurrence of carboxylated alicyclic molecules as important elements of the aliphatic portion of soil humic acids and a pathway from lignin is consistent with recent findings.

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

Elucidation of the Roles of Water on the Reactivity of Surface Intermediates in Carboxylic Acid Ketonization on TiO 2

The effects of water on the carboxylic acid ketonization reaction over solid Lewis-acid catalysts were examined by nuclear magnetic resonance (NMR) spectroscopy, diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), temperature-programmed desorption (TPD), and kinetic measurements. Acetic acid and propanoic acid were used as model compounds, and P25 TiO 2 was used as a model catalyst to represent the anatase TiO 2 since the rutile phase only contributes to <2.5% of the overall ketonization activity of P25 TiO 2 . The kinetic measurement showed that introducing H 2 O vapor in gaseous feed decreases the ketonization reaction rate by increasing the intrinsic activation barrier of gas-phase acetic acid on anatase TiO 2 . Quantitative TPD of acetic acid indicated that H 2 O does not compete with acetic acid for Lewis sites. Instead, as indicated by combined approaches of NMR and DRIFTS, H 2 O associates with the adsorbed acetate or acetic acid intermediates on the catalyst surface and alters their reactivities for the ketonization reaction. There are multiple species present on the anatase TiO 2 surface upon carboxylic acid adsorption, including molecular carboxylic acid, monodentate carboxylate, and chelating/bridging bidentate carboxylates. The presence of H 2 O vapor increases the coverage of the less reactive bridging bidentate carboxylate associated with adsorbed H 2 O, leading to lower ketonization activity on hydrated anatase TiO 2 . In conclusion, surface hydroxyl groups, which are consumed by interaction with carboxylic acid upon the formation of surface acetate species, do not impact the ketonization reaction.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗