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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 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
DOE OSTI2013

Chemically Activated Formation of Organic Acids in Reactions of the Criegee Intermediate with Aldehydes and Ketones

Reactions of the Criegee intermediate (CI, .CH2OO.) are important in atmospheric ozonolysis models. In this work, we compute the rates for reactions between .CH2OO. and HCHO, CH3CHO and CH3COCH3 leading to the formation of secondary ozonides (SOZ) and organic acids. Relative to infinitely separated reactants, the SOZ in all three cases is found to be 48–51 kcal mol-1 lower in energy, formed via 1,3- cycloaddition of .CH2OO. across the CQO bond. The lowest energy pathway found for SOZ decomposition is intramolecular disproportionation of the singlet biradical intermediate formed from cleavage of the O–O bond to form hydroxyalkyl esters. These hydroxyalkyl esters undergo concerted decomposition providing a low energy pathway from SOZ to acids. Geometries and frequencies of all stationary points were obtained using the B3LYP/MG3S DFT model chemistry, and energies were refined using RCCSD(T)-F12a/cc-pVTZ-F12 single-point calculations. RRKM calculations were used to obtain microcanonical rate coefficients (k(E)) and the reservoir state method was used to obtain temperature and pressure dependent rate coefficients (k(T, P)) and product branching ratios. At atmospheric pressure, the yield of collisionally stabilized SOZ was found to increase in the order HCHO o CH3CHO o CH3COCH3 (the highest yield being 10-4 times lower than the initial .CH2OO. concentration). At low pressures, chemically activated formation of organic acids (formic acid in the case of HCHO and CH3COCH3, formic and acetic acid in the case of CH3CHO) was found to be the major product channel in agreement with recent direct measurements. Collisional energy transfer parameters and the barrier heights for SOZ reactions were found to be the most sensitive parameters determining SOZ and organic acid yield.

Environmental Molecular Sciences Laboratory↗
DOE OSTI2016

Phosphate Speciation under Organic‐Acid‐Promoted Dissolution of Phosphorus‐Sorbed Ferrihydrite–Boehmite Mixtures: Implications For Soil Phosphorus

Core Ideas Phosphate speciation determines its bioavailability in soils. Phosphate molecular speciation changes occur upon organic‐acid‐promoted dissolution. Results imply that phosphate in acid soils preferentially associated with Fe(III) oxides. Organic‐acid‐promoted dissolution of phosphate is a primary mechanism for enhancing the bioavailability of sorbed, inorganic soil phosphate. Bioavailability of P is, however, dependent on its speciation. Hence, the main objective of this study was to characterize changes in phosphate speciation as a function of pH levels (4–8) during citrate‐promoted dissolution of phosphate adsorbed on ferrihydrite–boehmite mixtures using two different sizes of ferrihydrite. A combination of batch dissolution kinetics and P K‐X‐ray absorption near‐edge structure (XANES) spectroscopy was used. Trends in shifts of white‐line peak energy and full width at half maximum height of P K‐XANES spectra indicated that the phosphate bonding configuration on ferrihydrite–boehmite as single minerals and mineral mixtures was predominantly binuclear–bidentate complexes at pH levels of 4, 6, and 8. When citrate was added to the ferrihydrite–boehmite mixtures with bound phosphate (pH 4 and 6), phosphate was preferentially released from boehmite, resorbed onto ferrihydrite, and precipitated to form noncrystalline FePO 4 minerals. A reverse trend was observed at alkaline pH. These results suggest the potential for excessive P release in P‐enriched acidic soils during a redox event due to preferential association of P to Fe(III) phases.

Adam, Nadia↗
DOE OSTI2013

Field and Laboratory Studies of Reactions between Atmospheric Water Soluble Organic Acids and Inorganic Particles

Atmospheric inorganic particles undergo complex heterogeneous reactions that change their physicochemical properties. Depletion of chloride in sea salt particles was reported in previous field studies and was attributed to the acid displacement of chlorides with inorganic acids, such as nitric and sulfuric acids [1-2]. Recently, we showed that NaCl can react with water soluble organic acids (WSOA) and release gaseous hydrochloric acid (HCl) resulting in formation of organic salts [3]. A similar mechanism is also applicable to mixed WSOA/nitrate particles where multi-phase reactions are driven by the volatility of nitric acid. Furthermore, secondary organic material, which is a complex mixture of carboxylic acids, exhibits the same reactivity towards chlorides and nitrates. Here, we present a systematic study of reactions between atmospheric relevant WSOA, SOM, and inorganic salts including NaCl, NaNO3, and Ca(NO3)2 using complementary micro-spectroscopy analysis.

Acid Replacement↗
DOE OSTI2020

Domesticating a food spoilage yeast into an organic acid–tolerant metabolic engineering host: Lactic acid production by engineered Zygosaccharomyces bailii

Lactic acid represents an important class of commodity chemicals, which can be produced by microbial cell factories. However, due to the toxicity of lactic acid at lower pH, microbial production requires the usage of neutralizing agents to maintain neutral pH. Zygosaccharomyces bailii, a food spoilage yeast, can grow under the presence of organic acids used as food preservatives. This unique trait of the yeast might be useful for producing lactic acid. With the goal of domesticating the organic acid!tolerant yeast as a metabolic engineering host, seven Z. bailii strains were screened in a minimal medium with 10 g/L of acetic, or 60 g/L of lactic acid at pH 3. The Z. bailii NRRL Y7239 strain was selected as the most robust strain to be en- gineered for lactic acid production. By applying a PAN!ARS!based CRISPR!Cas9 system consisting of a transfer RNA promoter and NAT selection, we demonstrated the targeted deletion of ADE2 and site!specific integration of Rhizopus oryzae ldhA coding for lactate dehydrogenase into the PDC1 locus. The resulting pdc1::ldhA strain produced 35 g/L of lactic acid without ethanol production. Here, this study de- monstrates the feasibility of the CRISPR!Cas9 system in Z. bailii, which can be applied for a fundamental study of the species.

59 BASIC BIOLOGICAL SCIENCES↗
NASA NTRS2007

Nanoparticles modified with multiple organic acids

Surface-modified nanoparticles of boehmite, and methods for preparing the same. Aluminum oxyhydroxide nanoparticles are surface modified by reaction with selected amounts of organic acids. In particular, the nanoparticle surface is modified by reactions with two or more different carboxylic acids, at least one of which is an organic carboxylic acid. The product is a surface modified boehmite nanoparticle that has an inorganic aluminum oxyhydroxide core, or part aluminum oxyhydroxide core and a surface-bonded organic shell. Organic carboxylic acids of this invention contain at least one carboxylic acid group and one carbon-hydrogen bond. One embodiment of this invention provides boehmite nanoparticles that have been surface modified with two or more acids one of which additional carries at least one reactive functional group. Another embodiment of this invention provides boehmite nanoparticles that have been surface modified with multiple acids one of which has molecular weight or average molecular weight greater than or equal to 500 Daltons. Yet, another embodiment of this invention provides boehmite nanoparticles that are surface modified with two or more acids one of which is hydrophobic in nature and has solubility in water of less than 15 by weight. The products of the methods of this invention have specific useful properties when used in mixture with liquids, as filler in solids, or as stand-alone entities.

Cook, Ronald Lee↗
DOE OSTI2021

Corrosion of Ferrous Structural Alloys in Biomass Derived Fuels and Organic Acids

This work investigated the corrosivity of biomass-derived liquid fuels and organic acids associated with bio-oils and conducted a corrosion compatibility evaluation of several structural ferrous alloys in the fuels and acids. Here, the acidity parameters and solution conductivity values were higher in raw pyrolysis bio-oils than postprocessed oils with significant corrosion attack for carbon steel and Fe-2.25Cr-1Mo. However, higher-grade stainless steels, ferritic Fe-15Cr (15Cb) and austenitic types 304L and 316L, showed negligible corrosion loss, whereas lower-Cr ferritic grades 409, 410, and 416 were attacked. Metal leaching tests and electrochemical impedance spectroscopy measurements revealed superior corrosion resistance of 316 over 410 stainless steels in solutions of formic and oxalic acids that can be present in bio-oils. The corrosion evaluation methods utilized in this work provide effective screening tools to identify the compatible structural alloys for bio-oils.

09 BIOMASS FUELS↗
DOE OSTI2011

Recovery of organic acids

A method is disclosed for the recovery of an organic acid from a dilute salt solution in which the cation of the salt forms an insoluble carbonate salt. A tertiary amine and CO.sub.2 are introduced to the solution to form the insoluble carbonate salt and a complex between the acid and an amine. A water immiscible solvent, such as an alcohol, is added to extract the acid/amine complex from the dilute salt solution to a reaction phase. The reaction phase is continuously dried and a product between the acid and the solvent, such as an ester, is formed.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2015

Interactions between hydrated cement paste and organic acids: Thermodynamic data and speciation modeling

Interactions of short-chain organic acids with hydrated cement phases affect structure durability in the agro-food and nuclear waste industries but can also be used to modify cement properties. Most previous studies have been experimental, performed at fixed concentrations and pH, without quantitatively discriminating among polyacidity effects, or complexation and salt precipitation processes. This paper addresses such issues by thermodynamic equilibrium calculations for acetic, citric, oxalic, succinic acids and a simplified hydrated CEM-I. The thermodynamic constants collected from the literature allow the speciation to be modeled over a wide range of pH and concentrations. Citric and oxalic had a stronger chelating effect than acetic acid, while succinic acid was intermediate. Similarly, Ca-citrate and Ca-oxalate salts were more insoluble than Ca-acetate and Ca-succinate salts. Regarding aluminium complexation, hydroxyls, sulfates, and acid competition was highlighted. The exploration of acid mixtures showed the preponderant effect of oxalate and citrate over acetate and succinate.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
NASA NTRS2012

Hydrogen Isotope Measurements of Organic Acids and Alcohols by Pyrolysis-GC-MS-TC-IRMS: Application to Analysis of Experimentally Derived Hydrothermal Mineral-Catalyzed Organic Products

We report results of experiments to measure the H isotope composition of organic acids and alcohols. These experiments make use of a pyroprobe interfaced with a GC and high temperature extraction furnace to make quantitative H isotope measurements. This work compliments our previous work that focused on the extraction and analysis of C isotopes from the same compounds [1]. Together with our carbon isotope analyses our experiments serve as a "proof of concept" for making C and H isotope measurements on more complex mixtures of organic compounds on mineral surfaces in abiotic hydrocarbon formation processes at elevated temperatures and pressures. Our motivation for undertaking this work stems from observations of methane detected within the Martian atmosphere [2-5], coupled with evidence showing extensive water-rock interaction during Mars history [6-8]. Methane production on Mars could be the result of synthesis by mineral surface-catalyzed reduction of CO2 and/or CO by Fischer-Tropsch Type (FTT) reactions during serpentization [9,10]. Others have conducted experimental studies to show that FTT reactions are plausible mechanisms for low-molecular weight hydrocarbon formation in hydrothermal systems at mid-ocean ridges [11-13]. Our H isotope measurements utilize an analytical technique combining Pyrolysis-Gas Chromatograph-Mass Spectrometry-High Temperature Conversion-Isotope Ratio Mass Spectrometry (Py-GC-MS-TC-IRMS). This technique is designed to carry a split of the pyrolyzed GC-separated product to a Thermo DSQII quadrupole mass spectrometer as a means of making qualitative and semi-quantitative compositional measurements of separated organic compounds, therefore both chemical and isotopic measurements can be carried out simultaneously on the same sample.

Socki, Richard A.↗
DOE OSTI2018

Electrosorption of organic acids from aqueous bio-oil and conversion into hydrogen via microbial electrolysis cells

Neutralization of the bio-oil pH has been shown to generate a neutralized bio-oil aqueous phase (NBOAP) that includes most of the acidic components and a neutralized bio-oil organic phase (NBOOP) that includes hydrophobic organics, such as phenols. NBOOP can be used for fuel production, while NBOAP can be fed to microbial electrolysis cells (MECs) for hydrogen production. After pH neutralization, some organic acidic components remain in NBOOP. This work is focused on capturing acidic compounds from NBOOP through water extraction and electrosorption, and demonstrating hydrogen production via MECs. Capacitive deionization (CDI) is proven effective in capturing ions from NBOOP-contacted water and NBOAP via electrosorption. Captured acidic compounds enable the MEC application to effectively produce renewable hydrogen. Chemical oxygen demand (COD) removal of 49.2%, 61.5%, and 60.8% for 2, 4, and 10 g/L-anode/day loading were observed, corresponding to a total COD degradation of 0.19 g/L, 0.79 g/L, and 1.3 g/L, respectively. A maximum hydrogen productivity of 4.3 L-H 2 /L-anode/day was obtained. Major compounds in the water phase such as fatty acids, sugar derivatives, furanic and phenolic compounds were converted to hydrogen with an efficiency of 80–90%. Lastly, this approach may lead the entire biomass pyrolysis process to be an overall carbon-neutral process.

09 BIOMASS FUELS↗
DOE OSTI2022

Imidazolium-Type Anion Exchange Membranes for Improved Organic Acid Transport and Permselectivity in Electrodialysis

Most commercial anion exchange membranes (AEMs) deploy quaternary ammonium moieties. Alternative cation moieties have been explored in AEMs for fuel cells, but there are no studies focused examining alternative tethered cations in AEMs for ionic separations—such as organic acid anion transport via electrodialysis. H-cell and conductivity experiments demonstrate that tethered benzyl 1-methyl imidazolium groups in polysulfone AEMs enhance lactate conductivity by 49% and improved lactate anion flux by 24x when compared to a quaternary benzyl ammonium polysulfone AEM. An electrodialysis demonstration with the imidazolium-type AEM showed a 2x improvement in lactate anion flux and 20% improvement in permselectivity when benchmarked against the quaternary ammonium AEM. Molecular dynamics and 2D NOESY NMR revealed closer binding of lactate anions to the imidazolium cations when compared to the quaternary ammonium cation. It is posited that this closer binding is responsible to greater flux values observed with imidazolium-type AEM.

36 MATERIALS SCIENCE↗
DOE OSTI2015

Hydrolysis of Ketene Catalyzed by Formic Acid: Modification of Reaction Mechanism, Energetics, and Kinetics with Organic Acid Catalysis

The hydrolysis of ketene (H2C=C=O) to form acetic acid involving two water molecules and also separately in the presence of one to two water molecules and formic acid (FA) was investigated. Our results show that, while the currently accepted indirect mechanism, involving addition of water across the carbonyl C=O bond of ketene to form an ene-diol followed by tautomerization of the ene-diol to form acetic acid, is the preferred pathway when water alone is present, with formic acid as catalyst, addition of water across the ketene C=C double bond to directly produce acetic acid becomes the kinetically favored pathway for temperatures below 400 K. We find not only that the overall barrier for ketene hydrolysis involving one water molecule and formic acid (H2C2O + H2O + FA) is significantly lower than that involving two water molecules (H2C2O + 2H(2)O) but also that FA is able to reduce the barrier height for the direct path, involving addition of water across the C=C double bond, so that it is essentially identical with (6.4 kcal/mol) that for the indirect ene-diol formation path involving addition of water across the C=O bond. For the case of ketene hydrolysis involving two water molecules and formic acid (H2C2O + 2H(2)O + FA), the barrier for the direct addition of water across the C=C double bond is reduced even further and is 2.5 kcal/mol lower relative to the ene-diol path involving addition of water across the C=O bond. In fact, the hydrolysis barrier for the H2C2O + 2H(2)O + FA reaction through the direct path is sufficiently low (2.5 kcal/mol) for it to be an energetically accessible pathway for acetic acid formation under atmospheric conditions. Given the structural similarity between acetic and formic acid, our results also have potential implications for aqueous-phase chemistry. Thus, in an aqueous environment, even in the absence of formic acid, though the initial mechanism for ketene hydrolysis is expected to involve addition of water across the carbonyl bond as is currently accepted, the production and accumulation of acetic acid will likely alter the preferred pathway to one involving addition of water across the ketene C=C double bond as the reaction proceeds.

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

Synthesis, Crystal Structure, Hirshfeld Surface Analysis, and Physicochemical Study of an Anhydrous Organic Acidic Cyclohexaphosphate

The new organic–inorganic hybrid [5-Cl-2-(CH{sub 3})C{sub 6}H{sub 3}NH{sub 3}]{sub 4}H{sub 2}P{sub 6}O{sub 18} has been synthesized by the slow evaporation method. X-ray diffraction on a single crystal shows that this acidic cyclohexaphosphate crystallized in the monoclinic space group C{sub 2/c} with a = 33.89(11) Å, b = 9.16(16) Å, c = 13.68(3) Å, β = 91.35(2)°, V = 4244.9(19) Å{sup 3} and Z = 4. {sup 31}P MAS-NMR and {sup 13}C CP/MAS-NMR results are in accordance with X-ray findings. Fluorescent study shows the blue photoluminescence. Furthermore, FT-IR analysis was studied and the complete vibrational assignments were done. Intermolecular interactions were analyzed using Hirshfeld surface analysis and the associated 2D fingerprint plots.

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

Solar-thermal membrane for dewatering aqueous organic-acid solutions

A thermally conductive porous membrane has been developed to directly absorb solar energy and conduct heat that can effectively evaporate liquid water at the interface between the membrane and the bulk feed solution. Here, black, porous, thermally conductive graphite foam support is employed as an effective photothermal-energy absorber and heat conductor that heats up an aqueous feed solution to produce vapor. Graphite nanoparticle-slurry coating is applied onto the foam surface to reduce the pore size and generate a microporous membrane. Then, application of a dense graphene oxide membrane coating as an active separation layer on the microporous nanoparticle surface of internal foam channels allows vapor permeation of volatile molecules. Acetic acid/water solution was studied as a model feed system to experimentally demonstrate effective separation. This model vapor permeation system demonstrates excellent acetic acid separation, with a separation factor of 8.3, under simulated 0.7 sun irradiation. The membrane hydrophobicity and nanostructure, including pore size and surface chemistry, played a significant role in enabling high permselectivity of water vapor over acetic acid molecules, as well as liquid solution. Pore size reduction from open pores to a nonporous dense layer in the membrane enables effective separation of water vapor from the organic vapor, while it reduces the permeation flux. Also, the hydrophilicity of the membrane surface shows ~3 times higher permeation flux with higher permselectivity, compared with the hydrophobic membrane surface. This work introduces a process of directly using renewable energy instead of conventional heating to drive selective separation of water from organic acids.

14 SOLAR ENERGY↗
NASA NTRS1974

Acoustic properties of organic acid mixtures in water

The variation of the rate of propagation of ultrasounds in organic acid mixtures in water points to structural changes caused by interactions that take place under conditions of thermal agitation, at different acid concentrations. At the same time, a difference is found in the changes in velocity as a function of the length of the carbon chain of the acids in the mixture as a result of their effect on the groups of water molecules associated by hydrogen bonds.

Macavei, I.↗
DOE OSTI2015

Enhancing photo‐catalytic production of organic acids in the cyanobacterium S ynechocystis sp. PCC 6803 Δ glg C , a strain incapable of glycogen storage

Summary A key objective in microbial biofuels strain development is to maximize carbon flux to target products while minimizing cell biomass accumulation, such that ideally the algae and bacteria would operate in a photo‐catalytic state. A brief period of such a physiological state has recently been demonstrated in the cyanobacterium S ynechocystis sp. PCC 6803 Δ glgC strain incapable of glycogen storage. When deprived of nitrogen, the Δ glgC excretes the organic acids alpha‐ketoglutarate and pyruvate for a number of days without increasing cell biomass. This study examines the relationship between the growth state and the photo‐catalytic state, and characterizes the metabolic adaptability of the photo‐catalytic state to increasing light intensity. It is found that the culture can transition naturally from the growth state into the photo‐catalytic state when provided with limited nitrogen supply during the growth phase. Photosynthetic capacity and pigments are lost over time in the photo‐catalytic state. Reversal to growth state is observed with re‐addition of nitrogen nutrient, accompanied by restoration of photosynthetic capacity and pigment levels in the cells. While the overall productivity increased under high light conditions, the ratio of alpha‐ketoglutarate/pyruvate is altered, suggesting that carbon partition between the two products is adaptable to environmental conditions.

09 BIOMASS FUELS↗