Thermal polycondensation of free amino acids with polyphosphoric acid.
Thermal polycondensation of free amino acids with polyphosphoric acid
AMINO ACID↗
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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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Thermal condensation of cytidylic acid in the presence of polyphosphoric acid.
Thermal condensation of cytidylic acid from mononucleotides in presence of polyphosphoric acid
CYTIDYLIC ACID↗
Condensation of cytidylic acid in the presence of polyphosphoric acid.
Condensation of cytidylic acid in presence of polyphosphoric acid
CYTIDYLIC ACID↗
Stress Corrosion Evaluation of Various Metallic Materials for the International Space Station Water Recycling System
A stress corrosion evaluation was performed on Inconel 625, Hastelloy C276, titanium commercially pure (TiCP), Ti-6Al-4V, Ti-6Al-4V extra low interstitial, and Cronidur 30 steel as a consequence of a change in formulation of the pretreatment for processing the urine in the International Space Station Environmental Control and Life Support System Urine Processing Assembly from a sulfuric acid-based to a phosphoric acid-based solution. The first five listed were found resistant to stress corrosion in the pretreatment and brine. However, some of the Cronidur 30 specimens experienced reduction in load-carrying ability.
Torres, P. D.↗
Impact of impurities on the α-LiIO{sub 3} crystal growth: Technique for measuring the “dead zone”
Lithium iodate (α-LiIO{sub 3}) single crystal is a promising nonlinear optical material, which used for efficient laser radiation conversion in the visible and near-IR regions. A technique for measuring the “dead zone” (ΔТ{sub dz}) of LiIO{sub 3} solutions has been developed; data on the impact of Fe(IO{sub 3}){sub 2}, AgIO{sub 3}, CsOH, H{sub 3}PO{sub 4}, and methyl methacrylate on the growth of the (100) face of α-LiIO{sub 3} crystals have been presented; and the dependences of the nucleation and motion of single steps on the degree of supersaturation have been measured. It is shown that the ΔТ{sub dz} value makes it possible to estimate the validity of solutions for growing α-LiIO{sub 3} crystals. The results of measuring the face growth rates and step velocities for KDP and α-LiIO{sub 3} crystals are compared.
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
Techno-Economic Evaluation of Cellulosic Ethanol Production Based on Pilot Biorefinery Data: a Case Study of Sweet Sorghum Bagasse Processed via L+SScF
Replacing fossil fuels with renewable fuels derived from lignocellulosic biomass can contribute to the mitigation of global warming and the economic development of rural communities. This will require lignocellulosic biofuels to become price competitive with fossil fuels. Techno-economic analyses can provide insights into which parts of the biofuel production process need to be optimized to reduce cost or energy use. Here, we used data obtained from a pilot biorefinery to model a commercial-scale biorefinery that processes lignocellulosic biomass to ethanol, with a focus on the minimum ethanol selling price (MESP). The process utilizes a phosphoric acid-catalyzed pre-treatment of sweet sorghum bagasse followed by liquefaction and simultaneous saccharification and co-fermentation (L+SScF) of hexose and pentose sugars by an engineered Escherichia coli strain. After validating a techno-economic model developed with the SuperPro Designer software for the conversion of sugarcane bagasse to ethanol by comparing it to a published Aspen Plus model, six different scenarios were modeled for sweet sorghum bagasse Under the most optimistic scenario, the ethanol can be produced at a cost close to the energy-equivalent price of gasoline. Aside from an increase in the price of gasoline, the gap between ethanol and gasoline prices could also be bridged by either a decrease in the cost of cellulolytic enzymes or development of value-added products from lignin.
Biofuel↗
Thermal polycondensation of free amino acids with polyphosphoric acid.
Thermal polycondensation of free amino acids with polyphosphoric acid
PHOSPHORIC ACID↗
Stability of the anodic growth porous tungsten oxide in different solutions
This article presents the study of the stability of the anodic growth porous tungsten oxide (WO{sub 3}) film in different solutions. As-anodized films are relatively stable in acidic electrolytes like sulphuric acid (H{sub 2}SO{sub 4}), hydrochloric acid (HCl) but not in oxalic acid. In higher pH solution, rate of dissolution of the WO{sub 3} film is higher. Annealing at 400 °C for 2 h transform the as-grown sample from amorphous phase to the crystalline phase and this significantly improve the stability of the film in high pH solution. Photocurrent measurements reveal that there is no significant difference of the electrolyte used (0.5 M H{sub 2}SO{sub 4}, 0.33 M H{sub 3}PO{sub 4}, 0.1 M sodium sulfate (Na{sub 2}SO{sub 4})) on the photocurrent. As-annealed films exhibit good stablility for the long photoelectrochemical (PEC) measurements (1700 s) in 0.5 M H{sub 2}SO{sub 4} and 0.1 M Na{sub 2}SO{sub 4}. There is no effect on the photocurrent for the variation of the concentration of the acidic solution (H{sub 2}SO{sub 4}). However, lower photocurrent was obtained as the concentration of Na{sub 2}SO{sub 4} was increased.
36 MATERIALS SCIENCE↗
Chemical and biological conversion of crude glycerol derived from waste cooking oil to biodiesel
Highlights: • Crude glycerol was converted to biodiesel by chemical and biological method. • Purified glycerol is a promising carbon source for lipid production from microbe. • The study created a green cycle of crude glycerol application in energy production. - Abstract: In this study, crude, purified, and pure glycerol were used to cultivate Trichosporon oleaginosus for lipid production which was then used as feedstock of biodiesel production. The purified glycerol was obtained from crude glycerol by removing soap with addition of H{sub 3}PO{sub 4} which converted soap to free fatty acids and then separated from the solution. The results showed that purified glycerol provided similar performance as pure glycerol in lipid accumulation; however, crude glycerol as carbon source had negatively impacted the lipid production of T. oleaginosus. Purified glycerol was later used to determine the optimal glycerol concentration for lipid production. The highest lipid yield 0.19 g/g glycerol was obtained at 50 g/L purified glycerol in which the biomass concentration and lipid content were 10.75 g/L and 47% w/w, respectively. An energy gain of 4150.51 MJ could be obtained with 1 tonne of the crude glycerol employed for biodiesel production through the process proposed in this study. The biodiesel production cost estimated was 6.32 US $/gal. Fatty acid profiles revealed that C16:0 and C18:1 were the major compounds of the biodiesel from the lipid produced by T. oleaginosus cultivated with crude and purified glycerol. The study found that purified glycerol was promising carbon source for biodiesel production.
09 BIOMASS FUELS↗
Phosphorylation of nucleosides with polyphosphoric acid.
Phosphorylation of nucleosides with polyphosphoric acid
PHOSPHORYLATION↗
Graphene oxide-silica nanohybrids as fillers for PA6 based nanocomposites
Graphene oxide (GO) was prepared by oxidation of graphite flakes by a mixture of H{sub 2}SO{sub 4}/H{sub 3}PO{sub 4} and KMnO{sub 4} based on Marcano's method. Two different masterbatches containing GO (33.3%) and polyamide-6 (PA6) (66.7%) were prepared both via solvent casting in formic acid and by melt mixing in a mini-extruder (Haake). The two masterbatches were then used to prepare PA6-based nanocomposites with a content of 2% in GO. For comparison, a nanocomposite by direct mixing of PA6 and GO (2%) and PA6/graphite nanocomposites were prepared, too. The oxidation of graphite into GO was assessed by X-ray diffraction (XRD), Micro-Raman spectroscopy, scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) analyses. All these techniques demonstrated the effectiveness of the graphite modification, since the results put into evidence that, after the acid treatment, interlayer distance, oxygen content and defects increased. SEM micrographs carried out on the nanocomposites, showed GO layers totally surrounded by polyamide-6, this feature is likely due to the strong interaction between the hydrophilic moieties located both on GO and on PA6. On the contrary, no interactions were observed when graphite was used as filler. Mechanical characterization, carried out by tensile and dynamic-mechanical tests, marked an improvement of the mechanical properties observed. Photoluminescence and EPR measurements were carried out onto nanoparticles and nanocomposites to study the nature of the interactions and to assess the possibility to use this class of materials as semiconductors or optical sensors.
77 NANOSCIENCE AND NANOTECHNOLOGY↗
Oxidative acylation using thioacids
Several important prebiotic reactions, including the coupling of amino acids into polypeptides by the formation of amide linkages, involve acylation. Theae reactions present a challenge to the understanding of prebiotic synthesis. Condensation reactions relying on dehydrating agents are either inefficient in aqueous solution or require strongly acidic conditions and high temperatures. Activated amino acids such as thioester derivatives have therefore been suggested as likely substrates for prebiotic peptide synthesis. Here we propose a closely related route to amide bond formation involving oxidative acylation by thioacids. We find that phenylalanine, leucine and phenylphosphate are acylated efficiently in aqueous solution by thioacetic acid and an oxidizing agent. From a prebiotic point of view, oxidative acylation has the advantage of proceeding efficiently in solution and under mild conditions. We anticipate that oxidative acylation should prove to be a general method for activating carboxylic acids, including amino acids.
Non-NASA Center↗
Hydration behavior of magnesium potassium phosphate cement and stability analysis of its hydration products through thermodynamic modeling
Magnesium potassium phosphate cement (MKPC) is normally applied in civil engineering because of its short setting time and superior mechanical properties. This study investigates the hydration behavior and hydration products of MKPC influenced by molar ratio between magnesia and phosphate (M/P ratio) through thermodynamic method. Results show that the composition of ultimate hydration products are controlled by concentration of KH{sub 2}PO{sub 4} and MgO, activity of water and pH value of solution. When M/P ratio is lower than 0.64, the hydration product is MgHPO{sub 4}·3H{sub 2}O; When M/P ratio is between 0.64 and 0.67, the hydration products are MgHPO{sub 4}·3H{sub 2}O and Mg{sub 2}KH(PO{sub 4}){sub 2}·15H{sub 2}O. When M/P ratio is between 0.67 and 1.00, hydration products are Mg{sub 2}KH(PO{sub 4}){sub 2}·15H{sub 2}O and KMgPO{sub 4}·6H{sub 2}O; When M/P ratio is higher than 1.00, the hydration product is KMgPO{sub 4}·6H{sub 2}O together with unreacted MgO. This study also investigated the effect of additives, namely B(OH){sub 3}, H{sub 3}PO{sub 4}, K{sub 2}HPO{sub 4} and KH{sub 2}PO{sub 4}. - Highlights: • A database particularly for MKPC system at 25°C, 0.1 MPa was established and verified. • The pH value corresponding to specific M/P ratio in MKPC system is successfully predicted at 25°C, 0.1 MPa. • The composition of hydration products influenced by M/P ratio and some additives is successfully predicted at 25°C, 0.1 MPa.
36 MATERIALS SCIENCE↗
Green synthesis, molecular docking, anti-oxidant and anti-inflammatory activities of α-aminophosphonates
The naturally viable α-amino acid surrogates have been synthesised via Kabachnik–Fields reaction by the condensation of 2-aminothiazole with various aldehydes and dialkyl phosphites in the presence of Caffeine hydrogen sulfate (CHS) as eco-friendly and reusable catalyst under microwave irradiation and solvent-free conditions. The title compounds were characterised by IR, {sup 1}H, {sup 13}C, {sup 31}P NMR and mass spectral data. All the synthesised (4a–j) compounds were screened for their insilico and in vitro studies. The results revealed that, out of all the titled compounds 4a, 4e, 4h and 4i have exhibited significant activity in terms of antioxidant and anti-inflammatory activity. In addition, molecular docking studies were also carried out against Cox-2 with celocoxib as the standard. .
60 APPLIED LIFE SCIENCES↗
Effect of precursor concentration on the electrical properties of LiFePO{sub 4} prepared by solvothermal method
Lithium iron phosphate (LiFePO{sub 4}) is frequently used for Li-ion battery cathode. LiFePO{sub 4} has the high specific capacity at 170 mAhg{sup −1}, stable voltage at 3.45 V, stable structure, cheap, and low toxicity. The objective of this research is investigating the effect of precursor concentration on the electrical properties of LiFePO{sub 4} prepared by solvothermal method. LiOH, FeSO{sub 4}, H{sub 3}PO{sub 4}, and citric acid were used as the precursors. The LiOH concentration was varied from 0.3 M to 1.8 M. The Fourier Transform Infrared Spectroscopy (FTIR) measurement identified the Fe-O, O-P-O, and P-O bonds which corresponding to LiFePO{sub 4}. The result of 4-point probe measurement shows that, among the prepared samples, the sample from the precursor concentration of 1.8 M has the highest electrical conductivity.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Sonoluminescence of Suspensions of Insoluble Chromium Carbonyl Nanoparticles in Water and Inorganic Acids
The preparation and sonoluminescence of Cr(CO){sub 6} nanodispersed suspensions in water, 83% H{sub 2}SO{sub 4}, and 74% H{sub 3}PO{sub 4} are described for the first time. In the spectra of single- and multibubble sonoluminescence of these suspensions, chromium atom lines are found that are analogous to the corresponding lines in the sonoluminescence spectra of true Cr(CO){sub 6} solutions in dodecane. Sonoluminescence of nanodispersed suspensions of metal carbonyl, by which the electronic temperature reached in the bubbles under sonolysis (from 6500 to 16 000 K in water and acids) was measured, expands the scope of the sonochemical model of injection of nanodroplets of low volatile compounds into cavitation bubbles due to the inclusion of injection of suspensions of insoluble substances into it.
77 NANOSCIENCE AND NANOTECHNOLOGY↗
Chromonic liquid crystalline nematic phase exhibited in binary mixture of two liquid crystals
A binary mixture of abietic acid and orthophosphoric acid (H{sub 3}PO{sub 4}) exhibits co-existence of biphasic region of Nematic+Isotropic (N+I), lyotropic Nematic (ND) and Smectic-G (SmG) phases. The mixture exhibits N+I, N and SmG phases at different concentrations and at different temperatures. Mixtures with all concentrations of abietic acid exhibit I→N+I→N→SmG phases sequentially when the specimen is cooled from its isotropic melt. These phases have been characterized by using differential scanning calorimetric, X-ray diffraction, and optical texture studies.
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
A Non-aqueous H 3 PO 4 Electrolyte Enables Stable Cycling of Proton Electrodes
A non-aqueous proton electrolyte is devised by dissolving H 3 PO 4 into acetonitrile. The electrolyte exhibits unique vibrational signatures from stimulated Raman spectroscopy. Such an electrolyte exhibits unique characteristics compared to aqueous acidic electrolytes: 1) higher (de)protonation potential for a lower desolvation energy of protons, 2) better cycling stability by dissolution suppression, and 3) higher Coulombic efficiency owing to the lack of oxygen evolution reaction. Two non-aqueous proton full cells exhibit better cycling stability, higher Coulombic efficiency, and less self-discharge compared to the aqueous counterpart.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗