SEARCH · Search NASA
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.
Urea is an essential fertilizer needed to meet the global demand for food. Currently, its production rate by reaction of carbon dioxide with ammonia is slow and the energy demand is high. Here we discuss strategies to overcome these challenges.
The question of whether the production of ammonia, from the reduction of nitrite by iron(II), is compatible with its use in the Strecker synthesis of amino acids, or whether the iron and the cyanide needed for the Strecker synthesis interfere with each other, is addressed. Results show that the presence of iron(II) appears to have little, or no, affect on the Strecker synthesis. The presence of cyanide does interfere with reduction of nitrite, but the reduction proceeds at cyanide/iron ratios of less than 4:1. At ratios of about 2:1 and less there is only a small effect. The two reactions can be combined to proceed in each other's presence, forming glycine from nitrite, Fe(+2), formaldehyde, and cyanide.
The question of whether the production of ammonia, from the reduction of nitrite by iron(II), is compatible with its use in the Strecker synthesis of amino acids, or whether the iron and the cyanide needed for the Strecker synthesis interfere with each other, is addressed. Results show that the presence of iron(II) appears to have little, or no, effect on the Strecker synthesis. The presence of cyanide does interfere with reduction of nitrite, but the reduction proceeds at cyanide/iron ratios of less than 4:1. At ratios of about 2:1 and less there is only a small effect. The reduction of nitrite and the Strecker can be combined to proceed in each other's presence, to yield glycine from a mixture of nitrite, Fe+2, formaldehyde, and cyanide.
It is postulated that amino acids were produced on the early earth from dilute aqueous solution of cyanide, carbonyls and ammonia (the Strecker synthesis RNH2 + R"R""C=O + KCN yields H-N(R)-C(R")(R"")-CO2H. We have studied the products obtained from dilute aqueous solutions of cyanide, formaldehyde (R"=R""=H), ammonia (R=H) and amino acids. Solutions in the pH range from 8 to 10. at room temperature and at reactant concentrations from 0.001 M to 0.3 M have been studied. With R= H product yields were low (less than 3%). Only with R"=R""=H and R represented by the following: CH2CO2H (glycine); CH(CH3)CO2H (alanine); CH(CH2CH3)CO2H (a-amino n=butyric acids); C(CH3)2(CO2H) (a-aminoisobutyric acid); CH(CH(CH3)2)CO2H (valine); and CH(CH2CO2H)CO2H (aspartic acid), were product yields high (greater than 10%). The yields of glycine were larger with R not equal to H. The prebiotic implications of these findings will be discussed.
The recent discovery of all five canonical nucleobases in samples from Bennu provides compelling evidence that some of life’s ingredients were synthesized abiotically in the parent body of this asteroid and/or its precedent components. However, due to the sample availability and the limited method for the analysis, the detailed distribution of nucleobases in the samples remains elusive. Here we report the concentrations of a diverse suite of nitrogen (N)-heterocycles including nucleobases extracted by 2% and 20% hydrochloric acid from a homogenized Bennu sample. The detection of both canonical and non-canonical nucleobase pairs confirms that these biologically important compounds are extraterrestrial. Pyrimidines are more abundant than purines—like the Orgueil meteorite, but unlike the Murchison meteorite and asteroid Ryugu samples—suggesting preferential synthesis in ammonia-rich ices from the outer Solar System. The distribution of other N-heterocycles is consistent with extensive aqueous alteration on the parent body. High concentrations of urea underscore its role in N-heterocycle synthesis. Our findings offer important information on the prebiotic inventory of N-heterocycles in the Solar System.
We propose to demonstrate the feasibility of a solar thermochemical looping technology to produce and store nitrogen (N 2 ) from air for the subsequent production of ammonia (NH 3 ) via an advanced two-stage process.
Na + -gated nanochannel membranes were synthesized on α-Al 2 O 3 supports by secondary growth for ammonia (NH 3 ) separation from a mixture gas containing NH 3 , hydrogen (H 2 ) and nitrogen (N 2 ) at high temperature and pressure. Here, the effects of synthesis parameters (number of seeding steps, aging time, synthesis time, and Si/Al ratio) on membrane properties were investigated by characterization and gas permeation testing. Under the optimized condition (two-time seeding, 8 h aging time, 5 h synthesis time, and gel composition of 1.05 Al 2 O 3 : 5 SiO 2 : 50 Na 2 O: 100 H 2 O), the best membranes achieved NH 3 /H 2 and NH 3 /N 2 selectivities of 328 ± 60 and 1106 ± 207, respectively at 200 °C and 21 bar. Separation performance of the membrane was shown to be highly dependent on the permeances of N 2 and H 2 , which were greatly influenced by the membrane quality.
Over the past few decades, inorganic nitride materials have grown in importance in part due to their potential as catalysts for the synthesis of NH 3 , a key ingredient in fertilizer and precursor to industrial chemicals. Of particular interest are the ternary (ABN) or higher-order nitrides with high metal-to-nitrogen ratios that show promise in enhancing NH 3 synthesis reaction rates and yields via heterogeneous catalysis or chemical looping. Although metal nitrides are predicted to be numerous, the stability of nitrogen triple bonds found in N 2 , especially in comparison to the metal–nitrogen bonds, has considerably hindered synthetic efforts to produce complex nitride compounds. In this study, we present an exhaustive down-selection process to identify ternary nitrides for a promising chemical looping NH 3 production mechanism. We also report on a facile and efficient two-step synthesis method that can produce well-characterized η-carbide Co 3 Mo 3 N/Fe 3 Mo 3 N or filled β-manganese Ni 2 Mo 3 N ternaries, as well as their associated quaternary, (Co,Fe) 3 Mo 3 N, (Fe,Ni) 2 Mo 3 N, and (Co,Ni) 2 Mo 3 N, solid solutions. To further explore the quaternary space, syntheses of (Co,Ni) 3 Mo 3 N (Ni ≤ 10 mol %) and Co 3 (Mo,W) 3 N (W ≤ 10 mol %) were also investigated. The structures of the nitrides were characterized via X-ray powder diffraction. The morphology and compositions were characterized with scanning electron microscopy. In conclusion, the multitude of chemically unique, but structurally related, nitrides suggests that properties such as nitrogen activity may be tunable, making the materials of great interest for NH 3 synthesis schemes.
The development of earth-abundant transition-metal complexes for electrocatalytic ammonia oxidation is needed to facilitate a renewable energy economy. Important to this goal is a fundamental understanding of how ammonia binds to complexes as a function of ligand geometry and electronic effects. Here, we report the synthesis and characterization of a series of Fe(II)–NH 3 complexes supported by tetradentate, facially-binding ligands with a combination of pyridine and N-heterocyclic carbene donors. Electronic modification of the supporting ligand led to significant shifts in the Fe III/II potential and variations in NH bond acidities. Finally, investigations of ammonia oxidation by cyclic voltammetry, controlled potential bulk electrolysis, and through addition of stoichiometric organic radicals, TEMPO and tBu3 ArO • are reported. No catalysis of oxidation of NH 3 to N 2 was observed, and 15 N 2 was detected only in reactions with tBu3 ArO • .
The 100th anniversary of a leading nitrogen fixation technology developer like CASALE SA is a reason to reflect over the 20th century successful solution of the problem of world food supply, and to look out for solutions for sustainable developments with respect to ammonia production. Here, we review the role of nitrogen as essential chemical constituent in photosynthesis and biology, and component of ammonia as it is used as fertilizer for primary production by photosynthesis for farming and food supply and its future role as energy carrier. While novel synthesis methods and very advanced synchrotron based x-ray analytical techniques are being developed, we feel it is important to refer to the historical and economical context of nitrogen. The breaking of the N≡N triple bond remains a fundamental chemical and energetic problem in this context. We review the electrochemical ammonia synthesis as an energetically and environmentally benign method. Two relatively novel X-ray spectroscopy methods, which are relevant for the molecular understanding of the catalysts and biocatalysts, i.e. soft X-ray absorption spectroscopy and nuclear resonant vibration spectroscopy are presented. We illustrate the perceived reality in fertilizer usage on the field, and fertilizer production in the factory complex with photos and thus provide a contrast to the academic view of the molecular process of ammonia function and production.
This paper reports on the non-enzymatic aqueous phase synthesis of amino acids from keto acids, ammonia and reducing agents. The facile synthesis of key metabolic intermediates, particularly in the glycolytic pathway, the citric acid cycle, and the first step of amino acid synthesis, lead to new ways of looking at the problem of biogenesis.
Given the growing emphasis on energy efficiency, environmental sustainability, and agricultural demand, there’s a pressing need for decentralized and scalable ammonia production. Converting nitrate ions electrochemically, which are commonly found in industrial wastewater and polluted groundwater, into ammonia offers a viable approach for both wastewater treatment and ammonia production yet limited by low producibility and scalability. Here we report a versatile and scalable solution-phase synthesis of high-entropy single-atom nanocages (HESA NCs) in which Fe and other five metals-Co, Cu, Zn, Cd, and In-are isolated via cyano-bridges and coordinated with C and N, respectively. Incorporating and isolating the five metals into the matrix of Fe resulted in Fe-C5 active sites with a minimized symmetry of lattice as well as facilitated water dissociation and thus hydrogenation process. As a result, the Fe-HESA NCs exhibited a high selectivity toward NH3 from the electrocatalytic reduction of nitrate with a Faradaic efficiency of 93.4% while maintaining a high yield rate of 81.4 m h -1 mg -1 .
Nucleic acid constituents synthesis from methane- ammonia-water mixture, hydrogen cyanide and formaldehyde in thermal-radiation environment
Rats were subjected to tail-cast suspension hypokinesia for 6 days with one leg immobilized in dorsal flexion by casting. Control animals were also tail-casted. The soleus, gastrocnemius and plantaris muscles of uncasted hypokinetic legs were smaller than control muscles. Dorsal flexion prevented atrophy of these muscles and caused the soleus to hypertrophy. The anterior muscles were unaffected by hypokinesia. The smaller size of the soleus of the uncasted leg relative to the dorsal flexed and weight bearing limbs correlated with slower protein synthesis and faster proteolysis. The capacity of this muscle to synthesize glutamine (gln), which carries nitrogenous waste from muscle was also measured. Although tissue homogenates showed higher activities of gln synthetase, the rate of de novo synthesis was not altered in intact muscle but the tissue ratio of gln/glutamate was decreased. Glutamate and ATP were not limiting for gln synthesis, but availability of ammonia may be a limiting factor for this process in hypokinesia.
The emergence of life on Earth could have benefitted from an extraterrestrial source of amino acids. Yet, the origin of these amino acids is still debated because they may have formed prior to the solar nebula or inside the parent body of meteorites. Here, we experimentally produced amino acids by exposing an interstellar model molecule (hexamethylenetetramine) to asteroid-like hydrothermal conditions (150 °C; pH 10). We conducted additional experiments in the presence of carboxylic acids and phyllosilicates to simulate asteroidal environments. Analyses via liquid chromatography–mass spectrometry show that glycine is the most abundant amino acid formed, but non-proteinogenic α-, β-, and γ-amino acids are also produced. This production of amino acids seems to be hampered by the presence of Fe-rich smectites, while the presence of Al-rich smectites largely stimulates it. Our findings evidence (1) the production of amino acids during hydrothermal alteration of a putative interstellar precursor, (2) the importance of the formose reaction from formaldehyde and ammonia, for amino acid synthesis in meteorites, and (3) the impact of organic–mineral interactions on the nature/distribution of the amino acids produced. Altogether, the fact that the production of amino acids, which are so central to living structures, can be achieved via organo–mineral interactions under hydrothermal conditions should put these processes at a focal point for research on the origin of extraterrestrial organic compounds and into the origin of life.
Weakening and cleaving N-H bonds is crucial for improving molecular ammonia oxidation catalysts. In this work, we report the synthesis and hydrogen atom abstraction chemistry of bis(ammonia) Cr porphyrin complexes Cr(TPP)(NH 3 ) 2 and Cr(TMP)(NH 3 ) 2 (TPP = 5,10,15,20-tetraphenyl-meso-porphyrin and TMP = 5,10,15,20-tetramesityl-meso-porphyrin) using bulky aryloxyl radicals. The triple hydrogen atom abstraction reaction results in the formation of Cr V (por)(≡N), with the nitride deriving from ammonia, as indicated by UV-Vis and FT-IR spectroscopy, and a single crystal structural determination of Cr(TPP)(≡N). Subsequent oxidation of this chromium(V)-nitrido complex results in the formation of Cr III (por), with scission of the Cr≡N bond. A computational analysis illustrates the progression from Cr II to Cr V and evaluates the energetics of abstracting hydrogen atoms from Cr II -NH 3 to generate Cr V ≡N. The formation and isolation of Cr V (por)(≡N) illustrates the stability of these species and the need to chemically activate the nitride moiety for atom transfer or N-N coupling reactivity.
A method and system for membrane-assisted production of high purity concentrated dimethyl carbonate by the reaction of carbon dioxide and methanol is provided. Carbon dioxide is recovered from flue gas or other dilute streams from industrial processes by a membrane and subsequent conversion takes place to an intermediate methyl carbamate by reacting of carbon dioxide with ammonia and methanol. For high-purity carbon dioxide obtained by one of the carbon capture technologies or by a process (such as, for example, ethanol fermentation process) the membrane reactor is replaced with a catalytic reactor for direct conversion of carbon dioxide to methyl carbamate by reacting with ammonia and methanol. The methyl carbamate is further reacted with methanol for conversion to dimethyl carbonate. An integrated reactive distillation process using side reactors is used for facilitating the catalytic reaction in the subject method for producing high purity dimethyl carbonate.
The commercial product resulting from this R&D project will enable cost-effective synthesis of the Carbon Neutral Liquid Fuel (CNLF) ammonia, a common chemical, at a small scale for energy and industrial applications using only intermittent renewable energy, water, and air as feedstocks. These products are also capable of producing electrical energy from the CNLF in a fuel cell mode of operation. Thus, the eventual commercial product enables both single direction production of either CLNF or electricity, or alternatively functions as a fully reversible, self-contained energy storage device. The renewed interest in developing electrolysis systems is driven, in part, by the burgeoning renewable, solar, and wind industries and the need for an energy conversion and storage technology that can convert intermittent solar and wind energy into the production of hydrogen. Electrolysis systems integrated into both distributed and central renewable power plants would utilize solar and wind energy as their primary power source to produce renewably generated hydrogen for local energy storage or chemical feedstock purposes. Ammonia is an excellent surrogate for hydrogen transportation. NH3 presents an attractive alternative to hydrogen as a working fluid in reversible devices towards a sustainable green energy-oriented future. Ammonia can be easily liquefied at room temperature at about 8 bar or at -33°C at ambient pressure. In contrast, the liquefaction temperature of hydrogen is -253°C at ambient pressure. NH3 has a significantly higher volumetric energy density (12.7 MJ/L) than compressed hydrogen (4.5 MJ/L at ~70 MPa) or liquefied hydrogen (8.5 MJ/L). Additionally, ammonia is a widely used raw material for agriculture fertilizer and thus has well-established storage, transport, and handling processes (about 180 million tons of ammonia are produced annually). Techno-economic analysis suggests ammonia is the least expensive fuel among hydrogen, gasoline, natural gas, liquefied petroleum gas, and methanol.