Adsorption of ammonium ion by coconut shell-activated carbon from aqueous solution: kinetic, isotherm, and thermodynamic studies.

PubMed

Boopathy, Ramasamy; Karthikeyan, Sekar; Mandal, Asit Baran; Sekaran, Ganesan

2013-01-01

Ammonium ions are one of the most encountered nitrogen species in polluted water bodies. High level of ammonium ion in aqueous solution imparts unpleasant taste and odor problems, which can interfere with the life of aquatics and human population when discharged. Many chemical methods are developed and being used for removal of ammonium ion from aqueous solution. Among various techniques, adsorption was found to be the most feasible and environmentally friendly with the use of natural-activated adsorbents. Hence, in this study, coconut shell-activated carbon (CSAC) was prepared and used for the removal of ammonium ion by adsorption techniques. Ammonium chloride (analytical grade) was purchased from Merck Chemicals for adsorption studies. The CSAC was used to adsorb ammonium ions under stirring at 100 rpm, using orbital shaker in batch experiments. The concentration of ammonium ion was estimated by ammonia distillate, using a Buchi distillation unit. The influence of process parameters such as pH, temperature, and contact time was studied for adsorption of ammonium ion, and kinetic, isotherm models were validated to understand the mechanism of adsorption of ammonium ion by CSAC. Thermodynamic properties such as ∆G, ∆H, and ∆S were determined for the ammonium adsorption, using van't Hoff equation. Further, the adsorption of ammonium ion was confirmed through instrumental analyses such as SEM, XRD, and FTIR. The optimum conditions for the effective adsorption of ammonium ion onto CSAC were found to be pH 9.0, temperature 283 K, and contact time 120 min. The experimental data was best followed by pseudosecond order equation, and the adsorption isotherm model obeyed the Freundlich isotherm. This explains the ammonium ion adsorption onto CSAC which was a multilayer adsorption with intraparticle diffusion. Negative enthalpy confirmed that this adsorption process was exothermic. The instrumental analyses confirmed the adsorption of ammonium ion onto CSAC.

Determination of ammonium in a buddingtonite sample by ion-chromatography

USGS Publications Warehouse

Klock, P.R.; Lamothe, P.J.

1986-01-01

An ion-chromatographic method for the direct determination of ammonium, potassium, and sodium in geologic materials is described. Samples are decomposed with a mixture of hydrofluoric and hydrochloric acids in a sealed polycarbonate bottle heated in a microwave oven. The ion-chromatograph separates the cations and determines them by conductivity measurement. The ammonium concentrations thus determined have been verified by use of an ammonia-specific electrode. A total of 32 analyses of ammonium salts by both techniques showed an average error of -4%, with a relative standard deviation (RSD) of 6%. The ammonium concentrations found in a buddingtonite sample had an RSD of 2.2% and their mean agreed with that obtained by the Kjeldahl method. By use of the prescribed dilution of the sample, detection limits of 0.1% can be achieved for all three cations. ?? 1986.

Conductivity studies of Chitosan doped with different ammonium salts: Effect of ion size

NASA Astrophysics Data System (ADS)

Mohan, C. Raja; Senthilkumar, M.; Jayakumar, K.

2015-06-01

In the present investigation influence of ion size on the electrical properties of various ammonium salts of various concentrations doped with Chitosan liquid electrolyte has been studied. The attachment of ammonium salts with Chitosan has been confirmed through FTIR Spectrum. Polarizability is calculated from the refractive index data. Addition of ammonium salts increases the conductivity. It is also observed that increase in ion size, increases the ionic conductivity due to increase in amorphous nature of the material. Increase in concentration leads to increase in conductivity due to the presence of more number of free ions.

Ammonium Ion Binding to DNA G-Quadruplexes: Do Electrospray Mass Spectra Faithfully Reflect the Solution-Phase Species?

NASA Astrophysics Data System (ADS)

Balthasart, Françoise; Plavec, Janez; Gabelica, Valérie

2013-01-01

G-quadruplex nucleic acids can bind ammonium ions in solution, and these complexes can be detected by electrospray mass spectrometry (ESI-MS). However, because ammonium ions are volatile, the extent to which ESI-MS quantitatively could provide an accurate reflection of such solution-phase equilibria is unclear. Here we studied five G-quadruplexes having known solution-phase structure and ammonium ion binding constants: the bimolecular G-quadruplexes (dG4T4G4)2, (dG4T3G4)2, and (dG3T4G4)2, and the intramolecular G-quadruplexes dG4(T4G4)3 and dG2T2G2TGTG2T2G2 (thrombin binding aptamer). We found that not all mass spectrometers are equally suited to reflect the solution phase species. Ion activation can occur in the electrospray source, or in a high-pressure traveling wave ion mobility cell. When the softest instrumental conditions are used, ammonium ions bound between G-quartets, but also additional ammonium ions bound at specific sites outside the external G-quartets, can be observed. However, even specifically bound ammonium ions are in some instances too labile to be fully retained in the gas phase structures, and although the ammonium ion distribution observed by ESI-MS shows biases at specific stoichiometries, the relative abundances in solution are not always faithfully reflected. Ion mobility spectrometry results show that all inter-quartet ammonium ions are necessary to preserve the G-quadruplex fold in the gas phase. Ion mobility experiments, therefore, help assign the number of inner ammonium ions in the solution phase structure.[Figure not available: see fulltext.

Identification of alkyl dimethylbenzylammonium surfactants in water samples by solid-phase extraction followed by ion trap LC/MS and LC/MS/MS

USGS Publications Warehouse

Ferrer, I.; Furlong, E.T.

2001-01-01

A novel methodology was developed for the determination of alkyl (C12, C14, and C16) dimethylbenzylammonium chloride (benzalkonium chloride or BAC, Chemical Abstract Service number: 8001-54-5) in water samples. This method is based on solid-phase extraction (SPE) using polymeric cartridges, followed by high-performance liquid chromatography/ion trap mass spectrometry (LC/MS) and tandem mass spectrometry(MS/MS) detection, equipped with an electrospray interface in positive ion mode. Chromatographic separation was achieved for three BAC homologues by using a C18 column and a gradient of acetonitrile/10 millimolar aqueous ammonium formate. Total method recoveries were higher than 71% in different water matrices. The main ions observed by LC/MS were at mass-to-charge ratios (m/z) of 304, 332, and 360, which correspond to the molecular ions of the C12, C14, and C16 alkyl BAC, respectively. The unequivocal structural identification of these compounds in water samples was performed by LC/MS/MS after isolation and subsequent fragmentation of each molecular ion. The main fragmentation observed for the three different homologues corresponded to the loss of the toluyl group in the chemical structure, which leads to the fragment ions at m/z 212, 240, and 268 and a tropylium ion, characteristic of all homologues, at m/z 91. Detection limits for the methodology developed in this work were in the low nanogram-per-liter range. Concentration levels of BAC - ranging from 1.2 to 36.6 micrograms per liter - were found in surface-water samples collected downstream from different wastewater-treatment discharges, thus indicating its input and persistence through the wastewater-treatment process.

DETECTION OF THE AMMONIUM ION IN SPACE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cernicharo, J.; Tercero, B.; Fuente, A.

2013-07-01

We report on the detection of a narrow feature at 262816.73 MHz toward Orion and the cold prestellar core B1-bS which we attribute to the 1{sub 0}-0{sub 0} line of the deuterated ammonium ion, NH{sub 3}D{sup +}. The observations were performed with the IRAM 30 m radio telescope. The carrier has to be a light molecular species as it is the only feature detected over 3.6 GHz of bandwidth. The hyperfine structure is not resolved, indicating a very low value for the electric quadrupolar coupling constant of nitrogen which is expected for NH{sub 3}D{sup +} as the electric field overmore » the N nucleus is practically zero. Moreover, the feature is right at the predicted frequency for the 1{sub 0}-0{sub 0} transition of the ammonium ion, 262817 {+-} 6 MHz (3{sigma}), using rotational constants derived from new infrared data obtained in our laboratory in Madrid. The estimated column density is (1.1 {+-} 0.2) Multiplication-Sign 10{sup 12} cm{sup -2}. Assuming a deuterium enhancement similar to that of NH{sub 2}D, we derive N(NH{sub 4}{sup +}) {approx_equal} 2.6 Multiplication-Sign 10{sup 13} cm{sup -2}, i.e., an abundance for ammonium of a few 10{sup -11}.« less

Phosphate-dependent glutaminase in enterocyte mitochondria and its regulation by ammonium and other ions.

PubMed

Masola, B; Zvinavashe, E

2003-06-01

The effects of ammonium and other ions on phosphate dependent glutaminase (PDG) activity in intact rat enterocyte mitochondria were investigated. Sulphate and bicarbonate activated the enzyme in absence and presence of added phosphate. In presence of 10 mM phosphate, ammonium at concentrations <1 mM inhibited the enzyme. This inhibition was reversed by increased concentration of phosphate or sulphate. The inhibition of PDG by ammonium in presence of 10 mM phosphate was biphasic with respect to glutamine concentration, its effect being through a lowering of V(max) at glutamine concentration of Ammonium and bicarbonate ions may therefore be important physiological regulators of PDG. It is suggested that phosphate and other polyvalent ions may function by preventing product inhibition of the enzyme through promotion of PDG dimer formation. The dimerized enzyme may have a high affinity for glutamine and reduced sensitivity to inhibition by ammonium ions.

Purge-and-trap ion chromatography for the determination of trace ammonium ion in high-salinity water samples.

PubMed

Wang, Po-Yen; Wu, Jing-Yi; Chen, Hung-Jhen; Lin, Tzung-Yi; Wu, Chien-Hou

2008-04-25

It has always been assumed that purge-and-trap (P&T) method is only used for the analysis of volatile organic compounds (VOCs) in aqueous samples. In this paper, a novel P&T preconcentrator has been developed for the determination of trace amounts of ammonium ion in high-salinity water samples by ion chromatography (IC). Method performance is evaluated as a function of concentration of assistant purging material, purging time, and flow rate. Under the optimum P&T conditions with the purified nitrogen gas at flow rate 40 mL/min for 15.0 min at 40 degrees C, the overall collection efficiency is independent of the concentration of ammonium over the range 1.2-5.9 microM. The enrichment factor (EF) of ammonium correlates the ratio of the sample volume to the acceptor solution volume in the trap vessel, providing potentially unlimited increase of the ammonium signal. Our results indicate that environmental samples with low levels of ammonium in matrices with high concentrations of sodium can be easily analyzed and the detection limit down to 75 nM (1.35 ppb) level, corresponding to picomole of ammonia in the injected sample. Calibration graph was constructed with ammonium standards ranging from 0.05 to 6.0 microM and the linearity of the present method was good as suggested by the square of correlation coefficients being better than 0.997. Thus, we have demonstrated that the P&T-IC method allows the routine determination of ammonium ion in seawater samples without cation interferences.

Alkyl ether lipids, ion channels and lipid raft reorganization in cancer therapy.

PubMed

Jaffrès, Paul-Alain; Gajate, Consuelo; Bouchet, Ana Maria; Couthon-Gourvès, Hélène; Chantôme, Aurélie; Potier-Cartereau, Marie; Besson, Pierre; Bougnoux, Philippe; Mollinedo, Faustino; Vandier, Christophe

2016-09-01

Synthetic alkyl lipids, such as the ether lipids edelfosine (1-O-octadecyl-2-O-methyl-rac-glycero-3-phosphocholine) and ohmline (1-O-hexadecyl-2-O-methyl-rac-glycero-3-β-lactose), are forming a class of antitumor agents that target cell membranes to induce apoptosis and to decrease cell migration/invasion, leading to the inhibition of tumor and metastasis development. In this review, we present the structure-activity relationship of edelfosine and ohmline, and we point out differences and similarities between these two amphiphilic compounds. We also discuss the mechanisms of action of these synthetic alkyl ether lipids (involving, among other structures and molecules, membrane domains, Fas/CD95 death receptor signaling, and ion channels), and highlight a key role for lipid rafts in the underlying process. The reorganization of lipid raft membrane domains induced by these alkyl lipids affects the function of death receptors and ion channels, thus leading to apoptosis and/or inhibition of cancer cell migration. The possible therapeutic use of these alkyl lipids and the clinical perspectives for these lipids in prevention or/and treatment of tumor development and metastasis are also discussed. Copyright © 2016 Elsevier Inc. All rights reserved.

Evidence that two alkyl ester quaternary ammonium compounds lack substantial human skin-sensitizing potential.

PubMed

Jowsey, Ian R; Kligman, Albert M; White, Ian R; Goossens, An; Basketter, David A

2007-03-01

Alkyl ester quaternary ammonium compounds (ester quats) are used extensively in fabric rinse conditioners. It is important to document in the literature the outcome of historical studies that were performed to assess the risk of adverse skin effects associated with their use. (1) To document the outcomes of historical studies performed to evaluate the skin sensitizing potential of two ester quats (the di-[hardened tallow fatty acid] ester of 2,3-dihydroxypropyl-trimethyl ammonium chloride [HEQ] and the dialkyl ester of triethanol ammonium methyl sulfate [TEA-Quat]) and (2) to demonstrate that these ester quats lack marked skin-sensitizing potential in humans, such that they do not present a risk of contact allergy for consumers who use fabric rinse conditioners. Each material was assessed in the human maximization test in a panel of 25 volunteers. Diagnostic patch testing was also performed with each material in a population of 239 patients undergoing routine patch testing for suspected allergic contact dermatitis. These data are also considered in the context of an exposure-based quantitative risk assessment. Neither HEQ nor TEA-Quat was found to cause skin sensitization under the conditions of the human maximization test. No evidence of contact allergy to the materials was found among the relatively small population assessed by diagnostic patch testing. This study provides evidence that HEQ and TEA-Quat lack substantial skin-sensitizing potential in humans. Taken together with similar data for other ester quats, it suggests that compounds in this class are unlikely to be significant human contact allergens.

Removal of ammonium ion from water by Na-rich birnessite: Performance and mechanisms.

PubMed

Cheng, Ya; Huang, Tinglin; Shi, Xinxin; Wen, Gang; Sun, Yuankui

2017-07-01

Na-rich birnessite (NRB) was synthesized by a simple synthesis method and used as a high-efficiency adsorbent for the removal of ammonium ion (NH 4 + ) from aqueous solution. In order to demonstrate the adsorption performance of the synthesized material, the effects of contact time, pH, initial ammonium ion concentration, and temperature were investigated. Adsorption kinetics showed that the adsorption behavior followed the pseudo second-order kinetic model. The equilibrium adsorption data were fitted to Langmuir and Freundlich adsorption models and the model parameters were evaluated. The monolayer adsorption capacity of the adsorbent, as obtained from the Langmuir isotherm, was 22.61mg NH 4 + -N/g at 283K. Thermodynamic analyses showed that the adsorption was spontaneous and that it was also a physisorption process. Our data revealed that the higher NH 4 + adsorption capacity could be primarily attributed to the water absorption process and electrostatic interaction. Particularly, the high surface hydroxyl-content of NRB enables strong interactions with ammonium ion. The results obtained in this study illustrate that the NRB is expected to be an effective and economically viable adsorbent for ammonium ion removal from aqueous system. Copyright © 2016. Published by Elsevier B.V.

Induction of thermotropic bicontinuous cubic phases in liquid-crystalline ammonium and phosphonium salts.

PubMed

Ichikawa, Takahiro; Yoshio, Masafumi; Hamasaki, Atsushi; Taguchi, Satomi; Liu, Feng; Zeng, Xiang-bing; Ungar, Goran; Ohno, Hiroyuki; Kato, Takashi

2012-02-08

Two series of wedge-shaped onium salts, one ammonium and the other phosphonium, having 3,4,5-tris(alkyloxy)benzyl moieties, exhibit thermotropic bicontinuous "gyroid" cubic (Cub(bi)) and hexagonal columnar liquid-crystalline (LC) phases by nanosegregation between ionophilic and ionophobic parts. The alkyl chain lengths on the cationic moieties, anion species, and alkyl chain lengths on the benzyl moieties have crucial effects on their thermotropic phase behavior. For example, triethyl-[3,4,5-tris(dodecyloxy)benzyl]ammonium hexafluorophosphate forms the thermotropic Ia3d Cub(bi) LC phase, whereas an analogous compound with trifluoromethanesulfonate anion shows no LC properties. Synchrotron small-angle diffraction intensities from the Ia3d Cub(bi) LC materials provide electron density maps in the bulk state. The resulting maps show convincingly that the Ia3d Cub(bi) structure is composed of three-dimensionally interconnected ion nanochannel networks surrounded by aliphatic domains. A novel differential mapping technique has been applied successfully. The map of triethyl-[3,4,5-tris(decyloxy)benzyl]ammonium tetrafluoroborate has been subtracted from that of the analogous ammonium salt with hexafluorophosphate anion in the Ia3d Cub(bi) phases. The differential map shows that the counteranions are located in the core of the three-dimensionally interconnected nanochannel networks. Changing from trimethyl- via triethyl- to tripropylammonium cation changes the phase from columnar to Cub(bi) to no mesophase, respectively. This sensitivity to the widened shape for the narrow end of the molecule is explained successfully by the previously proposed semiquantitative geometric model based on the radial distribution of volume in wedge-shaped molecules. The LC onium salts dissolve lithium tetrafluoroborate without losing the Ia3d Cub(bi) LC phase. The Cub(bi) LC materials exhibit efficient ion-transporting behavior as a result of their 3D interconnected ion nanochannel networks

Novel polymer electrolytes based on cationic polyurethane with different alkyl chain length

NASA Astrophysics Data System (ADS)

Liu, Libin; Wu, Xiwen; Li, Tianduo

2014-03-01

A series of comb-like cationic polyurethanes (PUs) were synthesized by quaternizing different bromoalkane (C2H5Br, C8H17Br, and C14H29Br) with polyurethane. Solid polymer electrolytes were prepared by complexes cationic PUs with different content of LiClO4. All the solid polymer electrolytes had sufficient thermal stability as confirmed by TGA and exhibited a single-phase behavior evidenced by DSC results. For these electrolytes, FT-IR spectra indicated the formation of polymer-ion complexes. The ac impedance spectra show that the conductivity of the electrolytes follow the Arrhenius behavior, and ionic conductivity is associated with both the charge migration of ions between coordination sites and transmission between aggregates, as confirmed by FT-IR and SEM. Alkyl quaternary ammonium salts in the polymer backbone are recognized as inherent plasticizers, which make the electrolytes exhibit liquid-like behavior. The plasticizing effect of PU-C8 and PU-C14 electrolytes are more effective than that of PU-C2 electrolyte. Maximum ionic conductivity at room temperature for PU-C8 electrolytes containing 50 wt% LiClO4 reached 1.1 × 10-4 S cm-1. This work provides a new research clue that alkyl quaternary ammonium salts could be used as inherent plasticizers and hence make the system behave like a liquid with high ionic conductivity, while preserving the dimensional stability of the solids.

Phase Stabilization of Ammonium Nitrate

DTIC Science & Technology

2008-11-04

substance into the ammonium nitrate crystal structure. Salts containing ions larger or smaller than either ammonium or nitrate ions have been used...introducing another substance into the ammonium nitrate crystal structure. Salts containing ions larger or smaller than either ammonium or nitrate...two ionic attachment points should yield a nonmigrating salt due to difficulty of having simultaneous dissociation of two ionic structures

Reactive Uptake of Dimethylamine by Ammonium Sulfate and Ammonium Sulfate-Sucrose Mixed Particles.

PubMed

Chu, Yangxi; Chan, Chak K

2017-01-12

Short-chain alkyl amines can undergo gas-to-particle partitioning via reactive uptake by ammonium salts, whose phases have been thought to largely influence the extent of amine uptake. Previous studies mainly focused on particles of single ammonium salt at either dry or wet conditions without any addition of organic compounds. Here we report the uptake of dimethylamine (DMA) by ammonium sulfate (AS) and AS-sucrose mixed particles at different relative humidities (RHs) using an electrodynamic balance coupled with in situ Raman spectroscopy. DMA is selected as a representative of short-chain alkyl amines, and sucrose is used as a surrogate of viscous and hydrophilic organics. Effective DMA uptake was observed for most cases, except for the water-limiting scenario at <5% RH and the formation of an ultraviscous sucrose coating at 10% RH and below. DMA uptake coefficients (γ) were estimated using the particle mass measurements during DMA uptake. Addition of sucrose can increase γ by absorbing water or inhibiting AS crystallization and decrease γ by elevating the particle viscosity and forming a coating layer. DMA uptake can be facilitated for crystalline AS or retarded for aqueous AS with hydrophilic viscous organics (e.g., secondary organic material formed via the oxidation of biogenic volatile organic compounds) present in aerosol particles.

Charge properties and bacterial contact-killing of hyperbranched polyurea-polyethyleneimine coatings with various degrees of alkylation

NASA Astrophysics Data System (ADS)

Roest, Steven; van der Mei, Henny C.; Loontjens, Ton J. A.; Busscher, Henk J.

2015-11-01

Coatings of immobilized-quaternary-ammonium-ions (QUAT) uniquely kill adhering bacteria upon contact. QUAT-coatings require a minimal cationic-charge surface density for effective contact-killing of adhering bacteria of around 1014 cm-2. Quaternization of nitrogen is generally achieved through alkylation. Here, we investigate the contribution of additional alkylation with methyl-iodide to the cationic-charge density of hexyl-bromide alkylated, hyperbranched polyurea-polyethyleneimine coatings measuring charge density with fluorescein staining. X-ray-photoelectron-spectroscopy was used to determine the at.% alkylated-nitrogen. Also streaming potentials, water contact-angles and bacterial contact-killing were measured. Cationic-charge density increased with methyl-iodide alkylation times up to 18 h, accompanied by an increase in the at.% alkylated-nitrogen. Zeta-potentials became more negative upon alkylation as a result of shielding of cationiccharges by hydrophobic alkyl-chains. Contact-killing of Gram-positive Staphylococci only occurred when the cationic-charge density exceeded 1016 cm-2 and was carried by alkylated-nitrogen (electron-binding energy 401.3 eV). Gram-negative Escherichia coli was not killed upon contact with the coatings. There with this study reveals that cationic-charge density is neither appropriate nor sufficient to determine the ability of QUAT-coatings to kill adhering bacteria. Alternatively, the at.% of alkylated-nitrogen at 401.3 eV is proposed, as it reflects both cationic-charge and its carrier. The at.% N401.3 eV should be above 0.45 at.% for Gram-positive bacterial contact-killing.

UREA/ammonium ion removal system for the orbiting frog otolith experiment. [ion exchange resins for water treatment during space missions

NASA Technical Reports Server (NTRS)

Schulz, J. R.; Anselmi, R. T.

1976-01-01

The feasibility of using free urease enzyme and ANGC-101 ion exchange resin to remove urea and ammonium ion for space system waste water applications was studied. Specifically examined is the prevention of urea and ammonia toxicity in a 30-day Orbiting Frog Otolith (OFO) flight experiment. It is shown that free urease enzyme used in conjunction with ANGC-101 ion-exchange resin and pH control can control urea and amonium ion concentration in unbuffered recirculating water. In addition, the resin does not adversely effect the bullfrogs by lowering the concentration of cations below critical minimum levels. Further investigations on bioburden control, frog waste excretion on an OFO diet, a trade-off analysis of methods of automating the urea/ammonium ion removal system and fabrication and test of a semiautomated breadboard were recommended as continuing efforts. Photographs of test equipment and test animals are shown.

[Dental plaque microcosm biofilm behavior on a resin composite incorporated with nano-antibacterial inorganic filler containing long-chain alkyl quaternary ammonium salt].

PubMed

Junling, Wu; Qiang, Zhang; Ruinan, Sun; Ting, Zhu; Jianhua, Ge; Chuanjian, Zhou

2015-12-01

To develop a resin composite incorporated with nano-antibacterial inorganic filler containing long-chain alkyl quaternary ammonium salt, and to measure its effect on human dental plaque microcosm biofilm. A novel nano-antibacterial inorganic filler containing long-chain alkyl quaternary ammonium salt was synthesized according to methods introduced in previous research. Samples of the novel nano-antibacterial inorganic fillers were modified by a coupling agent and then added into resin composite at 0%, 5%, 10%, 15% or 20% mass fractions; 0% composite was used as control. A flexural test was used to measure resin composite mechanical properties. Results showed that a dental plaque microcosm biofilm model with human saliva as inoculum was formed. Colony-forming unit (CFU) counts, lactic acid production, and live/dead assay of biofilm on the resin composite were calculated to test the effect of the resin composite on human dental plaque microcosm biofilm. The incorporation of nano-antibacterial inorganic fillers with as much as 15% concentration into the resin composite showed no adverse effect on the mechanical properties of the resin composite (P > 0.05). Resin composite containing 5% or more nano-antibacterial inorganic fillers significantly inhibited the metabolic activity of dental plaque microcosm biofilm, suggesting its strong antibacterial potency (P < 0.05). This novel resin composite exhibited a strong antibacterial property upon the addition of up to 5% nano-antibacterial inorganic fillers, thereby leading to effective caries inhibition in dental application.

Determining fluoride ions in ammonium desulfurization slurry using an ion selective electrode method

NASA Astrophysics Data System (ADS)

Luo, Zhengwei; Guo, Mulin; Chen, Huihui; Lian, Zhouyang; Wei, Wuji

2018-02-01

Determining fluoride ions in ammonia desulphurization slurry using a fluoride ion selective electrode (ISE) is investigated. The influence of pH was studied and the appropriate total ionic strength adjustment buffer and its dosage were optimized. The impact of Fe3+ concentration on the detection results was analyzed under preferable conditions, and the error analysis of the ISE method’s accuracy and precision for measuring fluoride ion concentration in the range of 0.5-2000 mg/L was conducted. The quantitative recovery of F- in ammonium sulfate slurry was assessed. The results showed that when pH ranged from 5.5˜6 and the Fe3+ concentration was less than 750 mg/L, the accuracy and precision test results with quantitative recovery rates of 92.0%-104.2% were obtained.

Structural effect of quaternary ammonium chitin derivatives on their bactericidal activity and specificity.

PubMed

Morkaew, Tirut; Pinyakong, Onruthai; Tachaboonyakiat, Wanpen

2017-08-01

The effect of the quaternary ammonium chitin structure on the bactericidal activity and specificity against Escherichia coli and Staphylococcus aureus was investigated. Quaternary ammonium chitins were synthesized by the separate acylation of chitin (CT) with carboxymethyl trimethylammonium chloride (CMA), 3-carboxypropyl trimethylammonium chloride (CPA) and N-dodecyl-N,N-(dimethylammonio)butyrate (DDMAB). The successful acylation was confirmed by newly formed ester linkage. All three derivatives had a higher surface charge than chitin due to the additional positively charged quaternary ammonium groups. The N-short alkyl substituent (methyl) of CTCMA and CTCPA increased the hydrophilicity whilst the N-long alkyl substituent (dodecyl) of CTDDMAB increased the hydrophobicity compared to chitin. Chitin did not exhibit any bactericidal activity, while CTCMA and CTCPA completely killed E. coli and S. aureus in 30 and 60min, respectively, and CTDDMAB completely killed S. aureus in 10min but did not kill E. coli after a 2-h exposure. Therefore, the N-short alkyl substituent was more effective for killing E. coli and the N-long alkyl substituent conferred specific bactericidal activity against S. aureus. Copyright © 2017 Elsevier B.V. All rights reserved.

Developing force fields when experimental data is sparse: AMBER/GAFF-compatible parameters for inorganic and alkyl oxoanions.

PubMed

Kashefolgheta, Sadra; Vila Verde, Ana

2017-08-09

We present a set of Lennard-Jones parameters for classical, all-atom models of acetate and various alkylated and non-alkylated forms of sulfate, sulfonate and phosphate ions, optimized to reproduce their interactions with water and with the physiologically relevant sodium, ammonium and methylammonium cations. The parameters are internally consistent and are fully compatible with the Generalized Amber Force Field (GAFF), the AMBER force field for proteins, the accompanying TIP3P water model and the sodium model of Joung and Cheatham. The parameters were developed primarily relying on experimental information - hydration free energies and solution activity derivatives at 0.5 m concentration - with ab initio, gas phase calculations being used for the cases where experimental information is missing. The ab initio parameterization scheme presented here is distinct from other approaches because it explicitly connects gas phase binding energies to intermolecular interactions in solution. We demonstrate that the original GAFF/AMBER parameters often overestimate anion-cation interactions, leading to an excessive number of contact ion pairs in solutions of carboxylate ions, and to aggregation in solutions of divalent ions. GAFF/AMBER parameters lead to excessive numbers of salt bridges in proteins and of contact ion pairs between sodium and acidic protein groups, issues that are resolved by using the optimized parameters presented here.

Catalytic enantioselective synthesis of atropisomeric biaryls by a cation-directed O-alkylation

NASA Astrophysics Data System (ADS)

Jolliffe, John D.; Armstrong, Roly J.; Smith, Martin D.

2017-06-01

Axially chiral biaryls, as exemplified by 1,1‧-bi-2-naphthol (BINOL), are key components of catalysts, natural products and medicines. These materials are synthesized conventionally in enantioenriched form through metal-mediated cross coupling, de novo construction of an aromatic ring, point-to-axial chirality transfer or an atropselective transformation of an existing biaryl. Here, we report a highly enantioselective organocatalytic method for the synthesis of atropisomeric biaryls by a cation-directed O-alkylation. Treatment of racemic 1-aryl-2-tetralones with a chiral quinidine-derived ammonium salt under basic conditions in the presence of an alkylating agent leads to atropselective O-alkylation with e.r. up to 98:2. Oxidation with DDQ gives access to C2-symmetric and non-symmetric BINOL derivatives without compromising e.r. We propose that the chiral ammonium counterion differentiates between rapidly equilibrating atropisomeric enolates, leading to highly atropselective O-alkylation. This dynamic kinetic resolution process offers a general approach to the synthesis of enantioenriched atropisomeric materials.

Visible-light excitation of iminium ions enables the enantioselective catalytic β-alkylation of enals

NASA Astrophysics Data System (ADS)

Silvi, Mattia; Verrier, Charlie; Rey, Yannick P.; Buzzetti, Luca; Melchiorre, Paolo

2017-09-01

Chiral iminium ions—generated upon condensation of α,β-unsaturated aldehydes and amine catalysts—are used extensively by chemists to make chiral molecules in enantioenriched form. In contrast, their potential to absorb light and promote stereocontrolled photochemical processes remains unexplored. This is despite the fact that visible-light absorption by iminium ions is a naturally occurring event that triggers the mechanism of vision in higher organisms. Herein we demonstrate that the direct excitation of chiral iminium ions can unlock unconventional reaction pathways, enabling enantioselective catalytic photochemical β-alkylations of enals that cannot be realized via thermal activation. The chemistry uses readily available alkyl silanes, which are recalcitrant to classical conjugate additions, and occurs under illumination by visible-light-emitting diodes. Crucial to success was the design of a chiral amine catalyst with well-tailored electronic properties that can generate a photo-active iminium ion while providing the source of stereochemical induction. This strategy is expected to offer new opportunities for reaction design in the field of enantioselective catalytic photochemistry.

Improving Cellulose Dissolution in Ionic Liquids by Tuning the Size of the Ions: Impact of the Length of the Alkyl Chains in Tetraalkylammonium Carboxylate.

PubMed

Meng, Xiangqian; Devemy, Julien; Verney, Vincent; Gautier, Arnaud; Husson, Pascale; Andanson, Jean-Michel

2017-04-22

Twenty ionic liquids based on tetraalkylammonium cations and carboxylate anions have been synthesized, characterized, and tested for cellulose dissolution. The amount of cellulose dissolved in these ionic liquids depends strongly on the size of the ions: from 0 to 22 wt % cellulose can be dissolved at 90 °C. The best ionic liquids are less viscous and ammonium carboxylate based ionic liquids can dissolve as much as imidazolium-based ones. The viscosity of an ionic liquid can be decreased by the addition of DMSO as a cosolvent. After the addition of cosolvent, similar amounts of cellulose per ions are reached for most ionic liquids. As observed by rheology, ionic liquids with the longest alkyl chains form a gel when a high amount of cellulose is dissolved; this drastically limits their potential. Molecular simulations and IR spectroscopy have also been used with the aim of understanding how molecular interactions differ between efficient and inefficient ionic liquids. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Organic ion association in aqueous phase and ab initio-based force fields: The case of carboxylate/ammonium salts

NASA Astrophysics Data System (ADS)

Houriez, Céline; Vallet, Valérie; Réal, Florent; Meot-Ner Mautner, Michael; Masella, Michel

2017-10-01

We performed molecular dynamics simulations of carboxylate/methylated ammonium ion pairs solvated in bulk water and of carboxylate/methylated ammonium salt solutions at ambient conditions using an ab initio-based polarizable force field whose parameters are assigned to reproduce only high end quantum computations, at the Møller-Plesset second-order perturbation theory/complete basis set limit level, regarding single ions and ion pairs as isolated and micro-hydrated in gas phase. Our results agree with the available experimental results regarding carboxylate/ammonium salt solutions. For instance, our force field approach predicts the percentage of acetate associated with ammonium ions in CH3 COO-/CH3 NH3+ solutions at the 0.2-0.8M concentration scale to range from 14% to 35%, in line with the estimates computed from the experimental ion association constant in liquid water. Moreover our simulations predict the number of water molecules released from the ion first hydration shell to the bulk upon ion association to be about 2.0 ± 0.6 molecules for acetate/protonated amine ion pairs, 3.1 ± 1.5 molecules for the HCOO-/NH4+ pair and 3.3 ± 1.2 molecules for the CH3COO-/(CH3)4N+ pair. For protonated amine-based ion pairs, these values are in line with experiment for alkali/halide pairs solvated in bulk water. All these results demonstrate the promising feature of ab initio-based force fields, i.e., their capacity in accurately modeling chemical systems that cannot be readily investigated using available experimental techniques.

Properties of ammonium ion-water clusters: analyses of structure evolution, noncovalent interactions, and temperature and humidity effects.

PubMed

Pei, Shi-Tu; Jiang, Shuai; Liu, Yi-Rong; Huang, Teng; Xu, Kang-Ming; Wen, Hui; Zhu, Yu-Peng; Huang, Wei

2015-03-26

Although ammonium ion-water clusters are abundant in the biosphere, some information regarding these clusters, such as their growth route, the influence of temperature and humidity, and the concentrations of various hydrated clusters, is lacking. In this study, theoretical calculations are performed on ammonium ion-water clusters. These theoretical calculations are focused on determining the following characteristics: (1) the pattern of cluster growth; (2) the percentages of clusters of the same size at different temperatures and humidities; (3) the distributions of different isomers for the same size clusters at different temperatures; (4) the relative strengths of the noncovalent interactions for clusters of different sizes. The results suggest that the dipole moment may be very significant for the ammonium ion-water system, and some new stable isomers were found. The nucleation of ammonium ions and water molecules is favorable at low temperatures; thus, the clusters observed at high altitudes might not be present at low altitudes. High humidity can contribute to the formation of large ammonium ion-water clusters, whereas the formation of small clusters may be favorable under low-humidity conditions. The potential energy surfaces (PES) of these different sized clusters are complicated and differ according to the distribution of isomers at different temperatures. Some similar structures are observed between NH4(+)(H2O)n and M(H2O)n (where M represents an alkali metal ion or water molecule); when n = 8, the clusters begin to form the closed-cage geometry. As the cluster size increases, these interactions become progressively weaker. The successive binding energy at the DF-MP2-F12/VDZ-F12 level is better than that at the PW91PW91/6-311++G(3df, 3pd) level and is consistent with the experimentally determined values.

Inert Reassessment Document for Alkyl (C8-C24)

EPA Pesticide Factsheets

Inert Ingredient Tolerance Reassessments: Two Exemptions from theRequirement of a Tolerance for Alkyl (C8-C24) Benzenesulfonic Acid and its Ammonium, Calcium, Magnesium, Potassium, Sodium, and Zinc Salts

Rocking-Chair Ammonium-Ion Battery: A Highly Reversible Aqueous Energy Storage System.

PubMed

Wu, Xianyong; Qi, Yitong; Hong, Jessica J; Li, Zhifei; Hernandez, Alexandre S; Ji, Xiulei

2017-10-09

Aqueous rechargeable batteries are promising solutions for large-scale energy storage. Such batteries have the merit of low cost, innate safety, and environmental friendliness. To date, most known aqueous ion batteries employ metal cation charge carriers. Here, we report the first "rocking-chair" NH 4 -ion battery of the full-cell configuration by employing an ammonium Prussian white analogue, (NH 4 ) 1.47 Ni[Fe(CN) 6 ] 0.88 , as the cathode, an organic solid, 3,4,9,10-perylenetetracarboxylic diimide (PTCDI), as the anode, and 1.0 m aqueous (NH 4 ) 2 SO 4 as the electrolyte. This novel aqueous ammonium-ion battery demonstrates encouraging electrochemical performance: an average operation voltage of ca. 1.0 V, an attractive energy density of ca. 43 Wh kg -1 based on both electrodes' active mass, and excellent cycle life over 1000 cycles with 67 % capacity retention. Importantly, the topochemistry results of NH 4 + in these electrodes point to a new paradigm of NH 4 + -based energy storage. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

TREATMENT OF AMMONIUM NITRATE SOLUTIONS

DOEpatents

Boyer, T.W.; MacHutchin, J.G.; Yaffe, L.

1958-06-10

The treatment of waste solutions obtained in the processing of neutron- irradiated uranium containing fission products and ammonium nitrate is described. The object of this process is to provide a method whereby the ammonium nitrate is destroyed and removed from the solution so as to permit subsequent concentration of the solution.. In accordance with the process the residual nitrate solutions are treated with an excess of alkyl acid anhydride, such as acetic anhydride. Preferably, the residual nitrate solution is added to an excess of the acetic anhydride at such a rate that external heat is not required. The result of this operation is that the ammonium nitrate and acetic anhydride react to form N/sub 2/ O and acetic acid.

[Determination of di (hydrogenated tallow alkyl) dimethyl ammonium compounds in textile auxiliaries by ultra-high performance liquid chromatography-tandem mass spectrometry].

PubMed

Zhu, Feng

2015-01-01

A method has been developed for the determination of di (hydrogenated tallow alkyl) dimethyl ammonium compounds (DHTDMAC) in textile auxiliaries by ultra-high performance liquid chromatography-tandem mass spectrometry. (UPLC-MS/MS). The samples were extracted and diluted with acidified methanol by 5% (v/v) formic acid under ultrasonic assistance. The separation was performed on an Eclipse Plus C18 column (50 mm x 2.1 mm, 1.8 microm) using 0.1% (v/v) formic acid solution and methanol as the mobile phases. Identification and quantification were achieved by UPLC-MS/MS with electrospray ionization (ESI) source in positive ion mode and multiple reaction monitoring (MRM) mode. The results indicated that the calibration curve of DHTDMAC showed good linear relationship between peak area and mass concentration in the range of 10-280 microg/L with the correlation coefficient (r2) of 0.9991. The limit of detection (LOD, S/N=3) and the limit of quantification (LOQ, S/N= 10) of this method were 3 mg/kg and 10 mg/kg, respectively. The average recoveries from three typical textile auxiliary matrices including dispersant, antistatic agent and fabric softener, at three spiked levels were in the range of 97.2%-108.3% with the relative standard deviations (RSDs) of 1.5%-4.6%. The method is sensitive, accurate, simple and effective for the analysis of DHTDMAC in textile auxiliaries.

Emergence of innovative properties by replacement of nitrogen atom with phosphorus atom in quaternary ammonium ionic liquids: Insights from ab initio calculations and MD simulations

NASA Astrophysics Data System (ADS)

Ghatee, Mohammad Hadi; Bahrami, Maryam

2017-06-01

We investigate to contrasting structure, dynamic and thermophysical properties of quaternary ammonium and phosphonium ionic liquids (ILs) based on triethylalkylammonium [N222n]+ and triethylalkylphosphonium [P222n]+ cations (n = 5, 8, 12) and (bis(trifluoromethylsulfonyl)imide) anion [NTf2]- by quantum chemical calculations (QCC) and molecular dynamics (MD) simulations. QCCs conform to previous studies, showing that phosphonium cation alkyl chain rotational-energy-barrier is lower than ammonium cation. These molecular nature leads to no appreciable differences in their liquid density. However, their simulated transport properties (self-diffusion, conductivity, etc) are appreciably different. In particular, viscosity of phosphoniums are much lower than ammoniums. Ammoniums make nano-scale structural domains larger than phosphoniums. Employed analysis, vector re-orientational dynamics, ion-pair lifetime and nanostructure domain are in favor of faster dynamic for phosphoniums than ammoniums. [NTf2]- anion features a long lived pairing with ammoniums than phosphoniums. Overall, phosphoniums possess higher transference number, higher conductivity, and appreciably lower viscosity favorable for higher electrochemical performances.

Ion-pair partition of quarternary ammonium drugs: the influence of counter ions of different lipophilicity, size, and flexibility.

PubMed

Takács-Novák, K; Szász, G

1999-10-01

The ion-pair partition of quaternary ammonium (QA) pharmacons with organic counter ions of different lipophilicity, size, shape and flexibility was studied to elucidate relationships between ion-pair formation and chemical structure. The apparent partition coefficient (P') of 4 QAs was measured in octanol/pH 7.4 phosphate buffer system by the shake-flask method as a function of molar excess of ten counter ions (Y), namely: mesylate (MES), acetate (AC), pyruvate (PYRU), nicotinate (NIC), hydrogenfumarate (HFUM), hydrogenmaleate (HMAL), p-toluenesulfonate (PTS), caproate (CPR), deoxycholate (DOC) and prostaglandin E1 anion (PGE1). Based on 118 of highly precise logP' values (SD< 0.05), the intrinsic lipophilicity (without external counter ions) and the ion-pair partition of QAs (with different counter ions) were characterized. Linear correlation was found between the logP' of ion-pairs and the size of the counter ions described by the solvent accessible surface area (SASA). The lipophilicity increasing effect of the counter ions were quantified and the following order was established: DOC approximate to PGE1 > CPR approximate to PTS > NIC approximate to HMAL > PYRU approximate to AC approximate to MES approximate to HFUM. Analyzing the lipophilicity/molar ratio (QA:Y) profile, the differences in the ion-pair formation were shown and attributed to the differences in the flexibility/rigidity and size both of QA and Y. Since the largest (in average, 300 X) lipophilicity enhancement was found by the influence of DOC and PGE1 and considerable (on average 40 X) increase was observed by CPR and PTS, it was concluded that bile acids and prostaglandin anions may play a significant role in the ion-pair transport of quaternary ammonium drugs and caproic acid and p-toluenesulfonic acid may be useful salt forming agents to improve the pharmacokinetics of hydrophilic drugs.

Alkyl Pyrocarbonate Electrolyte Additives for Performance Enhancement of Li Ion Cells

NASA Technical Reports Server (NTRS)

Smart, M. C.; Ratnakumar, B. V.; Surampudi, S.

2000-01-01

Lithium ion rechargeable batteries are being developed for various aerospace applications under a NASA-DoD Interagency program. These applications require further improvements in several areas, specifically in the cycle life for LEO and GEO satellites and in the low temperature performance for the Mars Lander and Rover missions. Accordingly, we have been pursuing research studies to achieve improvement in the low temperature performance, long cycle life and active life of Li ion cells. The studies are mainly focused on electrolytes, to identify newer formulations of new electrolyte additives to enhance Li permeability (at low temperatures) and stability towards the electrode. The latter approach is particularly aimed at the formation suitable SEI (solid electrolyte interphase) on carbon electrodes. In this paper, we report the beneficial effect of using alkyl pyrocarbonates as electrolyte additives to improve the low temperature performance of Li ion cells.

Products and kinetics of the liquid-phase reaction of glyoxal catalyzed by ammonium ions (NH4(+)).

PubMed

Nozière, Barbara; Dziedzic, Pawel; Córdova, Armando

2009-01-08

Glyoxal, a common atmospheric gas, has been reported to be depleted in some regions of the atmosphere. The corresponding sink could be accounted for by reactions in or at the surface of atmospheric particles, but these reactions were not identified. Recently, we showed that inorganic ammonium ions, NH(4)(+), are efficient catalysts for reactions of carbonyl compounds, including glyoxal, in the liquid phase. To determine whether ammonium-catalyzed reactions can contribute to depletion of glyoxal in the atmosphere, the reactivity of this compound in aqueous solutions containing ammonium salts (ammonium sulfate, chloride, fluoride, and phosphate) at 298 K has been studied. The products identified by LC-HRMS and UV absorption revealed a mechanism involving two distinct pathways: a Bronsted acid pathway and an iminium pathway. The kinetics of the iminium pathway was studied by monitoring formation of a specific product. This pathway was second order in glyoxal in most of the solutions studied and should therefore be second order in most ammonium-containing aerosols in the atmosphere. The corresponding rate constant, k(II) (M(-1) s(-1)), increased strongly with ammonium ion activity, a(NH(4)(+)), and pH: k(II) (M(-1) s(-1)) = (2 +/- 1) x 10(-10) exp((1.5 +/- 0.8)aNH(4)(+)) exp((2.5 +/- 0.2)pH). This iminium pathway is a lower limit for the ammonium-catalyzed consumption of glyoxal, but the contribution of the acid pathway is expected to be small in tropospheric aerosols. With these results the reactive uptake of glyoxal on ammonium-containing aerosols was estimated and shown to be a possible explanation for depletion of this compound in Mexico City.

Quaternary ammonium promoted ultra selective and sensitive fluorescence detection of fluoride ion in water and living cells.

PubMed

Li, Long; Ji, Yuzhuo; Tang, Xinjing

2014-10-21

Highly selective and sensitive fluorescent probes with a quaternary ammonium moiety have been rationally designed and developed for fast and sensitive fluorescence detection of fluoride ion (F(-) from NaF, not TBAF) in aqueous solution and living cells. With the sequestration effect of quaternary ammonium, the detection time was less than 2 min and the detection limit of fluoride ion was as low as 0.57 ppm that is among the lowest detection limits in aqueous solutions of many fluoride fluorescence probes in the literature.

Role of sucrose in the heterogeneous uptake of dimethylamine by ammonium sulfate aerosol particles

NASA Astrophysics Data System (ADS)

Chu, Y.; Chan, C. K.

2016-12-01

Alkyl amines are important alkaline gases besides ammonia in the atmosphere and widely detected in both gas and particle phases. Heterogeneous uptake by pre-existing particles containing acids as well as ammonium salts is one of the major pathways of alkyl amines partitioning into aerosols. Recently, phase state of ammonium salt particles has been revealed to largely affect the degree of alkyl amines uptake. Using an electrodynamic balance coupled with Raman spectroscopy, we extend the study by investigating the alkyl amine uptake by ammonium sulfate (AS) - sucrose mixed particles, since ambient aerosols usually consist of a mixed phase of organics and inorganics. Sucrose is a surrogate of hydrophilic viscous organics that can alter the phase of AS at low relative humidity (RH) and dimethylamine (DMA) is selected for its abundance amongst alkyl amine compounds. DMA uptake occurred effectively at not only 70% RH but also RH as low as 10%, significantly below the AS crystallization point. The net uptake coefficient decreased as RH decreased for fixed initial AS - sucrose particle compositions. Interestingly, it followed a first increasing then decreasing trend as sucrose molar fraction increased from 0 to 0.5, at RH below 30%. Sucrose, albeit inert to DMA vapor, indirectly affected the interaction between DMA and AS - sucrose particles. On one hand, it absorbed water at low RH and delayed the efflorescence of AS to promote DMA uptake. On the other hand, the particle became more viscous with higher sucrose concentration and exhibited an effective mass transport barrier. Hence, the uptake of alkyl amines may occur slowly once ammonium salts are mixed with viscous organics, such as those secondary organic materials formed via the oxidation of biogenic volatile organic compounds, in the particle phase. Acknowledgment This work is supported by Research Grants Council (RGC) of Hong Kong Special Administrative Region, China (GRF 16300214). The grant from Hong Kong RGC Ph

Seasonal dynamics of nitrate and ammonium ion concentrations in soil solutions collected using MacroRhizon suction cups.

PubMed

Kabala, Cezary; Karczewska, Anna; Gałka, Bernard; Cuske, Mateusz; Sowiński, Józef

2017-07-01

The aims of the study were to analyse the concentration of nitrate and ammonium ions in soil solutions obtained using MacroRhizon miniaturized composite suction cups under field conditions and to determine potential nitrogen leaching from soil fertilized with three types of fertilizers (standard urea, slow-release urea, and ammonium nitrate) at the doses of 90 and 180 kg ha -1 , applied once or divided into two rates. During a 3-year growing experiment with sugar sorghum, the concentration of nitrate and ammonium ions in soil solutions was the highest with standard urea fertilization and the lowest in variants fertilized with slow-release urea for most of the months of the growing season. Higher concentrations of both nitrogen forms were noted at the fertilizer dose of 180 kg ha -1 . One-time fertilization, at both doses, resulted in higher nitrate concentrations in June and July, while dividing the dose into two rates resulted in higher nitrate concentrations between August and November. The highest potential for nitrate leaching during the growing season was in July. The tests confirmed that the miniaturized suction cups MacroRhizon are highly useful for routine monitoring the concentration of nitrate and ammonium ions in soil solutions under field conditions.

Toxicity evaluation of selected ammonium-based ionic liquid forms with MCPP and dicamba moieties on Pseudomonas putida.

PubMed

Piotrowska, Aleksandra; Syguda, Anna; Wyrwas, Bogdan; Chrzanowski, Łukasz; Heipieper, Hermann J

2017-01-01

Combination of the hydrophilic herbicidal anion with hydrophobic, antimicrobial ammonium cation allows to obtain compounds in ionic liquid form with better properties then conventional herbicides. Both cation and anion can be modified by selection of herbicide and the length of alkyl chains in cation structure. However the knowledge of their potential toxic effects are still limited. Furthermore, the relation between hydrophobicity associated with the length of alkyl chains and toxicity for ionic liquids has not been thoroughly studied. Therefore we investigated toxic effects of herbicidal ionic liquid forms on growth inhibition, given as EC 50, of the common soil bacterium Pseudomonas putida. We thereby concentrated on quaternary ammonium salts. Analyzed compounds were composed of dicamba or MCPP moieties and cation with various alkyl chain lengths (n = 6,8,10) We compared them with commercial herbicides, and ammonium-based ionic liquids with neutral anion (Br - ). In addition, cis-trans isomerisation of unsaturated membrane fatty acids in Pseudomonas putida was applied as the proxy for toxicity and membrane activity. We showed that toxicity increased with the length of alkyl chains. However, this correlation is only valid for six and eight carbon atom in alkyl chains, where for n = 10 the EC 50 values rise by one order of magnitude. In our studies, the herbicidal ionic liquids [C 10 ,C 10 ,C 1 ,C 1 N][MCPP] and [C 10 ,C 10 ,C 1 ,C 1 N][dicamba] showed the lowest toxicity among analyzed quaternary ammonium salts and comparable toxicity with corresponding herbicides. No clear increase in toxicity could be followed by changing the anion moieties for ammonium-based ionic liquid forms. Copyright © 2016 Elsevier Ltd. All rights reserved.

The competition of charge remote and charge directed fragmentation mechanisms in quaternary ammonium salt derivatized peptides--an isotopic exchange study.

PubMed

Cydzik, Marzena; Rudowska, Magdalena; Stefanowicz, Piotr; Szewczuk, Zbigniew

2011-12-01

Derivatization of peptides as quaternary ammonium salts (QAS) is a promising method for sensitive detection by electrospray ionization tandem mass spectrometry (Cydzik et al. J. Pept. Sci. 2011, 17, 445-453). The peptides derivatized by QAS at their N-termini undergo fragmentation according to the two competing mechanisms - charge remote (ChR) and charge directed (ChD). The absence of mobile proton in the quaternary salt ion results in ChR dissociation of a peptide bond. However, Hofmann elimination of quaternary salt creates an ion with one mobile proton leading to the ChD fragmentation. The experiments on the quaternary ammonium salts with deuterated N-alkyl groups or amide NH bonds revealed that QAS derivatized peptides dissociate according to the mixed ChR-ChD mechanism. The isotopic labeling allows differentiation of fragments formed according to ChR and ChD mechanisms. © The Author(s) 2011. This article is published with open access at Springerlink.com

Ammonium boranes for the selective complexation of cyanide or fluoride ions in water.

PubMed

Hudnall, Todd W; Gabbaï, François P

2007-10-03

With the recognition of aqueous fluoride and cyanide ions as an objective, we have investigated the anion binding properties of two isomeric ammonium boranes, namely [p-(Mes2B)C6H4(NMe3)]+ ([1]+) and [o-(Mes2B)C6H4(NMe3)]+ ([2]+). These cationic boranes, which could be obtained by reaction of the known 4- and 2-dimesitylboryl-N,N-dimethylaniline with MeOTf, have been investigated both experimentally and computationally. They both react with fluoride and cyanide ions in organic solvents to afford the corresponding fluoroborate/ or cyanoborate/ammonium zwitterions 1F, 1CN, 2F, and 2CN. In aqueous solution, however, these cationic boranes behave as remarkably selective receptors. Indeed, [1]+ only complexes cyanide ions while [2]+ only complexes fluoride ions. In H2O/DMSO 60:40 vol (HEPES 6 mM, pH 7), the cyanide binding constant of [1]+ and the fluoride binding constant of [2]+ are respectively equal to 3.9 (+/-0.1) x 108 and 910 (+/-50) M-1. Structural and computational studies indicate that both steric and electronic effects contribute to the unusual selectivity displayed by these cationic boranes. Owing to favorable Coulombic effects, the para-derivative [1]+ has a very high affinity for cyanide; yet these effects are not sufficiently intense to allow complexation of the more efficiently hydrated and less basic fluoride anion. In the case of the ortho-derivative [2]+, the proximity of the ammonium moiety leads to an increase in the Lewis acidity of the boron center thus making fluoride binding possible. However, steric effects prevent cyanide coordination to the boron center of [2]+. Finally, cation [1]+ and [2]+ bind their dedicated anions reversibly and show a negligible response in the presence of other common anions including Cl-, Br-, I-, NO3-, OAc-, H2PO4-, and HSO4-.

Formation of low charge state ions of synthetic polymers using quaternary ammonium compounds.

PubMed

Nasioudis, Andreas; Joyce, William F; van Velde, Jan W; Heeren, Ron M A; van den Brink, Oscar F

2010-07-01

Factors such as high polymer dispersity and variation in elemental composition (of copolymers) often complicate the electrospray ionization mass spectrometry (ESI-MS) analysis of synthetic polymers with high molar mass. In the experiments described in this study, quaternary ammonium compounds were observed to facilitate the production of low charge state pseudomolecular ions when added to the spray solution for ESI-MS. This approach was then used for the ESI time-of-flight mass spectrometry (TOF-MS) analysis of synthetic polymers. Hexadecyltrimethylammonium chloride permitted the successful analysis of poly(ethylene glycol) of 2-40 kDa, poly(propylene glycol) and poly(tetramethylene glycol) oligomers. Increasing the quaternary ammonium compounds' concentration results in the production of low charge state pseudomolecular ions. A comparison of structurally different quaternary ammonium compounds showed that the best performance is expected from large molecules with specific charge localization, which leaves the charge available for interactions. The applicability of the method for the MS analysis of other polymeric systems was also studied. In the case of poly(tetramethylene glycol), the method not only shifted the distributions to higher m/z values but also allowed the detection of high molecular weight material that was not observed without addition of the modifier to the spray solution.

Antibacterial effect of composite resins containing quaternary ammonium polyethyleneimine nanoparticles

NASA Astrophysics Data System (ADS)

Yudovin-Farber, Ira; Beyth, Nurit; Weiss, Ervin I.; Domb, Abraham J.

2010-02-01

Quaternary ammonium polyethyleneimine (QA-PEI)-based nanoparticles were synthesized by crosslinking with dibromopentane followed by N-alkylation with various alkyl halides and further N-methylation with methyl iodide. Insoluble pyridinium-type particles were prepared by suspension polymerization of 4-vinyl pyridine followed by N-alkylation with alkyl halides. Polyamine-based nanoparticles embedded in restorative composite resin at 1% w/w were tested for antibacterial activity against Streptococcus mutans using direct contact test. Activity analysis revealed that the alkyl chain length of the QA-PEI nanoparticles plays a significant role in antibacterial activity of the reagent. The most potent compound was octyl-alkylated QA-PEI embedded in restorative composite resin at 1% w/w that totally inhibited S. mutans growth in 3-month-aged samples. This data indicates that restorative composite resin with antibacterial properties can be produced by the incorporation of QA-PEI nanoparticles.

To Break or to Brake Neuronal Network Accelerated by Ammonium Ions?

PubMed Central

Dynnik, Vladimir V.; Kononov, Alexey V.; Sergeev, Alexander I.; Teplov, Iliya Y.; Tankanag, Arina V.; Zinchenko, Valery P.

2015-01-01

Purpose The aim of present study was to investigate the effects of ammonium ions on in vitro neuronal network activity and to search alternative methods of acute ammonia neurotoxicity prevention. Methods Rat hippocampal neuronal and astrocytes co-cultures in vitro, fluorescent microscopy and perforated patch clamp were used to monitor the changes in intracellular Ca2+- and membrane potential produced by ammonium ions and various modulators in the cells implicated in neural networks. Results Low concentrations of NH4Cl (0.1–4 mM) produce short temporal effects on network activity. Application of 5–8 mM NH4Cl: invariably transforms diverse network firing regimen to identical burst patterns, characterized by substantial neuronal membrane depolarization at plateau phase of potential and high-amplitude Ca2+-oscillations; raises frequency and average for period of oscillations Ca2+-level in all cells implicated in network; results in the appearance of group of «run out» cells with high intracellular Ca2+ and steadily diminished amplitudes of oscillations; increases astrocyte Ca2+-signalling, characterized by the appearance of groups of cells with increased intracellular Ca2+-level and/or chaotic Ca2+-oscillations. Accelerated network activity may be suppressed by the blockade of NMDA or AMPA/kainate-receptors or by overactivation of AMPA/kainite-receptors. Ammonia still activate neuronal firing in the presence of GABA(A) receptors antagonist bicuculline, indicating that «disinhibition phenomenon» is not implicated in the mechanisms of networks acceleration. Network activity may also be slowed down by glycine, agonists of metabotropic inhibitory receptors, betaine, L-carnitine, L-arginine, etc. Conclusions Obtained results demonstrate that ammonium ions accelerate neuronal networks firing, implicating ionotropic glutamate receptors, having preserved the activities of group of inhibitory ionotropic and metabotropic receptors. This may mean, that ammonia

Ion Dynamics in a Mixed-Cation Alkoxy-Ammonium Ionic Liquid Electrolyte for Sodium Device Applications.

PubMed

Pope, Cameron R; Kar, Mega; MacFarlane, Douglas R; Armand, Michel; Forsyth, Maria; O'Dell, Luke A

2016-10-18

The ion dynamics in a novel sodium-containing room-temperature ionic liquid (IL) consisting of an ether-functionalised quaternary ammonium cation and bis(trifluoromethylsulfonyl)amide [NTf 2 ] anion with various concentrations of Na[NTf 2 ] have been characterised using differential scanning calorimetry, impedance spectroscopy, diffusometry and NMR relaxation measurements. The IL studied has been specifically designed to dissolve a relatively large concentration of Na[NTf 2 ] salt (over 2 mol kg -1 ) as this has been shown to improve ion transport and conductivity. Consistent with other studies, the measured ionic conductivity and diffusion coefficients show that the overall ionic mobility decreases with decreasing temperature and increasing salt content. NMR relaxation measurements provide evidence for correlated dynamics between the ether-functionalised ammonium and Na cations, possibly with the latter species acting as cross-links between multiple ammonium cations. Finally, preliminary cyclic voltammetry experiments show that this IL can undergo stable electrochemical cycling and could therefore be potentially useful as an electrolyte in a Na-based device. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

The formation of [M-H]+ ions in N-alkyl-substituted thieno[3,4-c]-pyrrole-4,6-dione derivatives during atmospheric pressure photoionization mass spectrometry.

PubMed

Sioud, Salim; Kharbatia, Najeh; Amad, Maan H; Zhu, Zhiyong; Cabanetos, Clement; Lesimple, Alain; Beaujuge, Pierre

2014-11-30

The formation of ions during atmospheric pressure photoionization (APPI) mass spectrometry in the positive mode usually provides radical cations and/or protonated species. Intriguingly, during the analysis of some N-alkyl-substituted thieno[3,4-c]pyrrole-4,6-dione (TPD) derivatives synthesized in our laboratory, unusual [M-H](+) ion peaks were observed. In this work we investigate the formation of [M-H](+) ions observed under APPI conditions. Multiple experimental parameters, including the type of ionization source, the composition of the solvent, the type of dopant, the infusion flow rate, and the length of the alkyl side chain were investigated to determine their effects on the formation of [M-H](+) ions. In addition, a comparison study of the gas-phase tandem mass spectrometric (MS/MS) fragmentation of [M + H](+) vs [M-H](+) ions and computational approaches were used. [M-H](+) ions were observed under APPI conditions. The type of dopant and the length of the alkyl chain affected the formation of these ions. MS/MS fragmentation of [M-H](+) and [M + H](+) ions exhibited completely different patterns. Theoretical calculations revealed that the loss of hydrogen molecules from the [M + H](+) ions is the most favourable condition under which to form [M-H](+) ions. [M-H](+) ions were detected in all the TPD derivatives studied here under the special experimental conditions during APPI, using a halogenated benzene dopant, and TPD containing substituted N-alkyl side chains with a minimum of four carbon atoms. Density functional theory calculations showed that for [M-H](+) ions to be formed under these conditions, the loss of hydrogen molecules from the [M + H](+)  ions is proposed to be necessary. Copyright © 2014 John Wiley & Sons, Ltd.

CHLORIDEDETERMINATION IN HIGH IONIC STRENGTH SOLUTION OF AMMONIUM ACETATE USING NEGATIVE ION ELECTRON SPRAY IONIZATION (HPLC/MS)

EPA Science Inventory

A precise ion chromatography method has been developed for the determination of chloride in high ionic strength ammonium acetate solutions (10-5 M-5 M) using sodium carbonate/sodium bicarbonate as eluent. Negative ion electrospray ionization (ESI) mass spectrometry was used for q...

Structure and electronic properties of ion pairs accompanying cyclic morpholinium cation and alkylphosphite anion based ionic liquids

NASA Astrophysics Data System (ADS)

Verma, Prakash L.; Singh, Priti; Gejji, Shridhar P.

2017-07-01

Molecular insights for the formation of ion pairs accompanying the cyclic ammonium cation based room temperature ionic liquids (RTILs) composed of alkyl substituted N-methylmorpholinium (RMMor) and alkylphosphite [(Rsbnd O)2PHdbnd O] (Rdbnd ethyl, butyl, hexyl, octyl) anion have been derived from the M06-2x level of theory. Electronic structures, binding energies, and spectral characteristics of the ion pairs underlying these RTILs have been characterized. The ion pair formation is largely governed by Csbnd H⋯O and other intermolecular interactions. Calculated binding energies increase with the increasing alkyl chain on either cation or alkylphosphite anion. The cation-anion binding reveals signature in the frequency down-(red) shift of the characteristic anionic Pdbnd O stretching whereas the Psbnd H stretching exhibits a shift in the opposite direction in vibrational spectra which has further been rationalized through molecular electron density topography. Correlations of measured electrochemical stability with the separation of frontier orbital energies and binding energies in the ion pairs have further been established.

A Stable Fluorinated and Alkylated Lithium Malonatoborate Salt for Lithium Ion Battery Application

DOE PAGES

Wan, Shun; Jiang, Xueguang; Guo, Bingkun; ...

2015-04-27

A new fluorinated and alkylated lithium malonatoborate salt, lithium bis(2-methyl-2-fluoromalonato)borate (LiBMFMB), has been synthesized for lithium ion battery application. A 0.8 M LiBMFMB solution is obtained in a mixture of ethylene carbonate (EC) and ethyl methyl carbonate (EMC) (1:2 by wt.). The new LiBMFMB based electrolyte exhibits good cycling stability and rate capability in LiNi0.5Mn1.5O4 and graphite based half-cells.

Generation and collision-induced dissociation of ammonium tetrafluoroborate cluster ions.

PubMed

Dain, Ryan P; Van Stipdonk, Michael J

2008-07-01

Singly and doubly charged cluster ions of ammonium tetrafluoroborate (NH4BF4) with general formula [(NH4BF4)nNH4]+ and [(NH4BF4)m(NH4)2]2+, respectively, were generated by electrospray ionization (ESI) and their fragmentation examined using collision-induced dissociation (CID) and ion-trap tandem mass spectrometry. CID of [(NH4BF4)nNH4]+ caused the loss of one or more neutral NH4BF4 units. The n = 2 cluster, [(NH4BF4)2NH4]+, was unique in that it also exhibited a dissociation pathway in which HBF4 was eliminated to create [(NH4BF4)(NH3)NH4]+. Dissociation of [(NH4BF4)m(NH4)2]2+ occurred through two general pathways: (a) 'fission' to produce singly charged cluster ions and (b) elimination of one or more neutral NH4BF4 units to leave doubly charged product ions. CID profiles, and measurements of changing precursor and product ion signal intensity as a function of applied collision voltage, were collected for [(NH4BF4)nNH4]+ and compared with those for analogous [(NaBF4)nNa]+ and [(KBF4)nK]+ ions to determine the influence of the cation on the relative stability of cluster ions. In general, the [(NH4BF4)nNH4]+ clusters were found to be easier to dissociate than both the sodium and potassium clusters of comparable size, with [(KBF4)nK]+ ions the most difficult to dissociate.

Efficacy of alkyl dimethyl benzyl ammonium chloride on suppression of Physalospora vaccinii in laboratory assays.

PubMed

Tubajika, K M

2006-10-01

Growth of Physalospora vaccinii on inoculated agar growth medium and cranberries treated with 0.1, 1, 10, 100, and 1,000 ppm of alkyl dimethyl benzyl ammonium chloride (ADBAC) was investigated in the laboratory. In vitro growth assays, the colony diameter, and mycelial dry weight of P. vaccinii was reduced at 1,000 ppm ADBAC. Mild or no reduction of fungal growth and mycelial dry weight was observed at concentrations less than 100 ppm when compared with the nonamended control. Growth of P. vaccinii on inoculated cranberries was inhibited by treatment with 10 and 100 ppm ADBAC. Complete inhibition of fungus growth was also achieved at 1,000 ppm ADBAC. Area under the disease progress curve values in wounded fruits were 75, 77, and 100% at 10, 100, and 1,000 ppm ADBAC, respectively, whereas area under the disease progress curve values in fruits immersed in ADBAC and pathogen were reduced 47 to 100% compared with the untreated fruits used as controls. No P. vaccinii or other fungi were detected on the control fruits inoculated with sterile distilled water. This is the first report on the use of ADBAC to control a field and storage rotting fungus, P. vaccinii. ADBAC is likely to be an important component to any integrated approach for reducing the risks associated with the presence of pathogenic microorganisms in or on foods.

Final report on the safety assessment of sodium cetearyl sulfate and related alkyl sulfates as used in cosmetics.

PubMed

Fiume, Monice; Bergfeld, Wilma F; Belsito, Donald V; Klaassen, Curtis D; Marks, James G; Shank, Ronald C; Slaga, Thomas J; Snyder, Paul W; Alan Andersen, F

2010-05-01

Sodium cetearyl sulfate is the sodium salt of a mixture of cetyl and stearyl sulfate. The other ingredients in this safety assessment are also alkyl salts, including ammonium coco-sulfate, ammonium myristyl sulfate, magnesium coco-sulfate, sodium cetyl sulfate, sodium coco/hydrogenated tallow sulfate, sodium coco-sulfate, sodium decyl sulfate, sodium ethylhexyl sulfate, sodium myristyl sulfate, sodium oleyl sulfate, sodium stearyl sulfate, sodium tallow sulfate, sodium tridecyl sulfate, and zinc coco-sulfate. These ingredients are surfactants used at concentrations from 0.1% to 29%, primarily in soaps and shampoos. Many of these ingredients are not in current use. The Cosmetic Ingredient Review (CIR) Expert Panel previously completed a safety assessment of sodium and ammonium lauryl sulfate. The data available for sodium lauryl sulfate and ammonium lauryl sulfate provide sufficient basis for concluding that sodium cetearyl sulfate and related alkyl sulfates are safe in the practices of use and concentration described in the safety assessment.

Liquid-liquid distribution of ion associates of tetrabromoindate(III) with quaternary ammonium counter ions.

PubMed

Yamamoto, K; Matsumoto, A

1997-11-01

The solvent extraction of an ion associate of tetrabromoindate(III) ion, InBr(-)(4), with quaternary ammonium cations (Q(+)) has been studied. The extraction constant (K(ex)) were determined for the ion associates of InBr(-)(4) with Q(+) between an aqueous phase and several organic phases (chloroform, chlorobenzene, benzene and toluene). A linear relationship was found between log K(ex) and the total number of carbon atoms in Q(+); from the slope of the lines, the contribution of a methylene group to log K(ex) was calculated to be 0.91 for the chloroform extraction system and 0.52 for the other extraction systems. The extractability with alkyltrimethylammonium cations was larger than that with symmetrical tetraalkylammonium cations and the mean difference in log K(ex) for two cations (one of each type) with the same number of carbon atoms was about 1.3. From the extraction constant obtained, the extractability of InBr(-)(4) among metal-halogeno complex anions was in the order TlBr(-)(4) > BiI(-)(4) > AuBr(-)(4) > AuCl(-)(4) > TlCl(-)(4) > InBr(-)(4) > CuCl(-)(2).

Electrospray ionization tandem mass spectrometry of ammonium cationized polyethers.

PubMed

Nasioudis, Andreas; Heeren, Ron M A; van Doormalen, Irene; de Wijs-Rot, Nicolette; van den Brink, Oscar F

2011-05-01

Quaternary ammonium salts (Quats) and amines are known to facilitate the MS analysis of high molar mass polyethers by forming low charge state adduct ions. The formation, stability, and behavior upon collision-induced dissociation (CID) of adduct ions of polyethers with a variety of Quats and amines were studied by electrospray ionization quadrupole time-of-flight, quadrupole ion trap, and linear ion trap tandem mass spectrometry (MS/MS). The linear ion trap instrument was part of an Orbitrap hybrid mass spectrometer that allowed accurate mass MS/MS measurements. The Quats and amines studied were of different degree of substitution, structure, and size. The stability of the adduct ions was related to the structure of the cation, especially the amine's degree of substitution. CID of singly/doubly charged primary and tertiary ammonium cationized polymers resulted in the neutral loss of the amine followed by fragmentation of the protonated product ions. The latter reveals information about the monomer unit, polymer sequence, and endgroup structure. In addition, the detection of product ions retaining the ammonium ion was observed. The predominant process in the CID of singly charged quaternary ammonium cationized polymers was cation detachment, whereas their doubly charged adduct ions provided the same information as the primary and tertiary ammonium cationized adduct ions. This study shows the potential of specific amines as tools for the structural elucidation of high molar mass polyethers. © American Society for Mass Spectrometry, 2011

A solid phase extraction-ion chromatography with conductivity detection procedure for determining cationic surfactants in surface water samples.

PubMed

Olkowska, Ewa; Polkowska, Żaneta; Namieśnik, Jacek

2013-11-15

A new analytical procedure for the simultaneous determination of individual cationic surfactants (alkyl benzyl dimethyl ammonium chlorides) in surface water samples has been developed. We describe this methodology for the first time: it involves the application of solid phase extraction (SPE-for sample preparation) coupled with ion chromatography-conductivity detection (IC-CD-for the final determination). Mean recoveries of analytes between 79% and 93%, and overall method quantification limits in the range from 0.0018 to 0.038 μg/mL for surface water and CRM samples were achieved. The methodology was applied to the determination of individual alkyl benzyl quaternary ammonium compounds in environmental samples (reservoir water) and enables their presence in such types of waters to be confirmed. In addition, it is a simpler, less time-consuming, labour-intensive, avoiding use of toxic chloroform and significantly less expensive methodology than previously described approaches (liquid-liquid extraction coupled with liquid chromatography-mass spectrometry). Copyright © 2013 Elsevier B.V. All rights reserved.

Evidence of ammonium ion-exchange properties of natural bentonite and application to ammonium detection.

PubMed

Zazoua, A; Kazane, I; Khedimallah, N; Dernane, C; Errachid, A; Jaffrezic-Renault, N

2013-12-01

Ammonium exchange with hybrid PVC-bentonite (mineral montmorillonite clay) thin film was revealed using FTIR spectroscopy, EDX, cyclic voltammetry and electrochemical impedance spectroscopy. The effect of ammonium exchange on the charge transfer resistance of PVC-bentonite hybrid thin film was attributed to a modification of the intersheet distance and hydration of bentonite crystals. The obtained impedimetric ammonium sensor shows a linear range of detection from 10(-4)M to 1M and a detection limit around 10(-6)M. © 2013.

Interplay between alkyl chain asymmetry and cholesterol addition in the rigid ion pair amphiphile bilayer systems

NASA Astrophysics Data System (ADS)

Huang, Fong-yin; Chiu, Chi-cheng

2017-01-01

Ion pair amphiphile (IPA), a molecular complex composed of a pair of cationic and anionic surfactants, has been proposed as a novel phospholipid substitute. Controlling the physical stability of IPA vesicles is important for its application developments such as cosmetic and drug deliveries. To investigate the effects of IPA alkyl chain combinations and the cholesterol additive on the structural and mechanical properties of IPA vesicular bilayers, we conducted a series of molecular dynamics studies on the hexadecyltrimethylammonium-dodecylsulfate (HTMA-DS) and dodecyltrimethylammonium-hexadecylsulfate (DTMA-HS) IPA bilayers with cholesterol. We found that both IPA bilayers are in the gel phase at 298 K, consistent with experimental observations. Compared with the HTMA-DS system, the DTMA-HS bilayer has more disordered alkyl chains in the hydrophobic region. When adding cholesterol, it induces alkyl chain ordering around its rigid sterol ring. Yet, cholesterol increases the molecular areas for all species and disturbs the molecular packing near the hydrophilic region and the bilayer core. Cholesterol also promotes the alkyl chain mismatch between the IPA moieties, especially for the DTMA-HS bilayer. The combined effects lead to non-monotonically enhancement of the membrane mechanical moduli for both IPA-cholesterol systems. Furthermore, cholesterol can form H-bonds with the alkylsulfate and thus enhance the contribution of alkylsulfate to the overall mechanical moduli. Combined results provide valuable molecular insights into the roles of each IPA component and the cholesterol on modulating the IPA bilayer properties.

Soft antimicrobial agents: synthesis and activity of labile environmentally friendly long chain quaternary ammonium compounds.

PubMed

Thorsteinsson, Thorsteinn; Másson, Már; Kristinsson, Karl G; Hjálmarsdóttir, Martha A; Hilmarsson, Hilmar; Loftsson, Thorsteinn

2003-09-11

A series of soft quaternary ammonium antimicrobial agents, which are analogues to currently used quaternary ammonium preservatives such as cetyl pyridinium chloride and benzalkonium chloride, were synthesized. These soft analogues consist of long alkyl chain connected to a polar headgroup via chemically labile spacer group. They are characterized by facile nonenzymatic and enzymatic degradation to form their original nontoxic building blocks. However, their chemical stability has to be adequate in order for them to have antimicrobial effects. Stability studies and antibacterial and antiviral activity measurements revealed relationship between activity, lipophilicity, and stability. Their minimum inhibitory concentration (MIC) was as low as 1 microg/mL, and their viral reduction was in some cases greater than 6.7 log. The structure-activity studies demonstrate that the bioactive compounds (i.e., MIC for Gram-positive bacteria of <10 microg/mL) have an alkyl chain length between 12 and 18 carbon atoms, with a polar headgroup preferably of a small quaternary ammonium group, and their acquired inactivation half-life must be greater than 3 h at 60 degrees C.

The Influence of the Anionic Counter-Ion on the Activity of Ammonium Substituted Hoveyda-Type Olefin Metathesis Catalysts in Aqueous Media

NASA Astrophysics Data System (ADS)

Gułajski, Łukasz; Grela, Karol

Polar olefin metathesis catalysts, bearing an ammonium group are presented. The electron withdrawing ammonium group not only activates the catalysts electronically, but at the same time makes the catalysts more hydrophilic. Catalysts can be therefore efficiently used not only in traditional media, such as methylene chloride and toluene, but also in technical-grade alcohols, alcohol— water mixtures and in neat water. Finally, in this overview the influence of the anionic counter-ion on the activity of ammonium substituted Hoveyda-type olefin metathesis catalysts in aqueous media is presented.

Fragmentation of Electrospray-produced Deprotonated Ions of Oligodeoxyribonucleotides Containing an Alkylated or Oxidized Thymidine

PubMed Central

Wang, Pengcheng; Williams, Renee T.; Guerrero, Candace R.; Ji, Debin; Wang, Yinsheng

2014-01-01

Alkylation and oxidation constitute major routes of DNA damage induced by endogenous and exogenous genotoxic agents. Understanding the biological consequences of DNA lesions often necessitates the availability of oligodeoxyribonucleotide (ODN) substrates harboring these lesions, and sensitive and robust methods for validating the identities of these ODNs. Tandem mass spectrometry is well suited for meeting these latter analytical needs. In the present study, we evaluated how the incorporation of an ethyl group to different positions (i.e., O2, N3 and O4) of thymine and the oxidation of its 5-methyl carbon impact collisionally activated dissociation (CAD) pathways of electrospray-produced deprotonated ions of ODNs harboring these thymine modifications. Unlike an unmodified thymine, which often manifests poor cleavage of the C3′-O3′ bond, the incorporation of an alkyl group to the O2 position and, to a much lesser extent, the O4 position, but not the N3 position of thymine, led to facile cleavage of the C3′-O3′ bond on the 3′ side of the modified thymine. Similar efficient chain cleavage was observed when thymine was oxidized to 5-formyluracil or 5-carboxyluracil, but not 5-hydroxymethyluracil. Additionally, with the support of computational modeling, we revealed that proton affinity and acidity of the modified nucleobases govern the fragmentation of ODNs containing the alkylated and oxidized thymidine derivatives, respectively. These results provided important insights into the effects of thymine modifications on ODN fragmentation. PMID:24664806

Ion-pair hollow-fiber liquid-phase microextraction of the quaternary ammonium surfactant dicocodimethylammonium chloride.

PubMed

Hultgren, Sofie; Larsson, Niklas; Nilsson, Bo F; Jönsson, Jan Ake

2009-02-01

A two-phase hollow-fiber (HF) liquid-phase microextraction (LPME) method was developed for determination of a quaternary ammonium compound surfactant, dicocodimethylammonium chloride, in aqueous samples. The porous HF was fixed on a metal rod support and was impregnated with approximately 6.6 microL of organic extractant, which was immobilized in the HF pores. Surfactant extraction was facilitated by addition of carboxylic acid to the sample forming neutral ion pairs with the quaternary ammonium compound. After extraction, the analyte was transferred from the organic extractant in the fiber pores by dissolving the 1-octanol into 100 microL methanol. The methanol extract was analyzed by liquid chromatography-mass spectrometry. The method was optimized (with optimized parameters in brackets) with regard to type of organic extractant (1-octanol), fiber length (2 cm), choice and concentration of anionic carrier (600 microg L(-1) octanoate), procedure of transfer to methanol (15-min sonication), sample volume (250 mL), extraction time (17 h), pH (10), and ionic strength (50 mM carbonate). Aspects influencing repeatability in LPME of (quaternary ammonium) surfactants are discussed. The enrichment factor achieved in 250-mL carbonate buffer was around 400. Due to matrix effects, the enrichment factors achieved when industrial process water was analyzed were 120 or about 30% of that in carbonate buffer. Detection limits of 0.3 microg L(-1) in carbonate buffer and 0.9 microg L(-1) in industrial process water were obtained. If the studied compound is seen as a model substance representing quaternary dialkylated dimethylated ammonium surfactants in general, the developed method may be applied to other quaternary ammonium surfactants.

Ion transport and structural dynamics in homologous ammonium and phosphonium-based room temperature ionic liquids

DOE Office of Scientific and Technical Information (OSTI.GOV)

Griffin, Philip J., E-mail: pgrif@seas.upenn.edu; Holt, Adam P.; Tsunashima, Katsuhiko

2015-02-28

Charge transport and structural dynamics in a homologous pair of ammonium and phosphonium based room temperature ionic liquids (ILs) have been characterized over a wide temperature range using broadband dielectric spectroscopy and quasi-elastic light scattering spectroscopy. We have found that the ionic conductivity of the phosphonium based IL is significantly enhanced relative to the ammonium homolog, and this increase is primarily a result of a lower glass transition temperature and higher ion mobility. Additionally, these ILs exhibit pronounced secondary relaxations which are strongly influenced by the atomic identity of the cation charge center. While the secondary relaxation in the phosphoniummore » IL has the expected Arrhenius temperature dependence characteristic of local beta relaxations, the corresponding relaxation process in the ammonium IL was found to exhibit a mildly non-Arrhenius temperature dependence in the measured temperature range—indicative of molecular cooperativity. These differences in both local and long-range molecular dynamics are a direct reflection of the subtly different inter-ionic interactions and mesoscale structures found in these homologous ILs.« less

Ion transport and structural dynamics in homologous ammonium and phosphonium-based room temperature ionic liquids

DOE Office of Scientific and Technical Information (OSTI.GOV)

Griffin, Phillip J.; Holt, Adam P.; Tsunashima, Katsuhiko

2015-02-01

Charge transport and structural dynamics in a homologous pair of ammonium and phosphonium based room temperature ionic liquids (ILs) have been characterized over a wide temperature range using broadband dielectric spectroscopy and quasi-elastic light scattering spectroscopy. We have found that the ionic conductivity of the phosphonium based IL is significantly enhanced relative to the ammonium homolog, and this increase is primarily a result of a lower glass transition temperature and higher ion mobility. Additionally, these ILs exhibit pronounced secondary relaxations which are strongly influenced by the atomic identity of the cation charge center. While the secondary relaxation in the phosphoniummore » IL has the expected Arrhenius temperature dependence characteristic of local beta relaxations, the corresponding relaxation process in the ammonium IL was found to exhibit a mildly non-Arrhenius temperature dependence in the measured temperature range-indicative of molecular cooperativity. These differences in both local and long-range molecular dynamics are a direct reflection of the subtly different inter-ionic interactions and mesoscale structures found in these homologous ILs.« less

Extrapolating Single Organic Ion Solvation Thermochemistry from Simulated Water Nanodroplets.

PubMed

Coles, Jonathan P; Houriez, Céline; Meot-Ner Mautner, Michael; Masella, Michel

2016-09-08

We compute the ion/water interaction energies of methylated ammonium cations and alkylated carboxylate anions solvated in large nanodroplets of 10 000 water molecules using 10 ns molecular dynamics simulations and an all-atom polarizable force-field approach. Together with our earlier results concerning the solvation of these organic ions in nanodroplets whose molecular sizes range from 50 to 1000, these new data allow us to discuss the reliability of extrapolating absolute single-ion bulk solvation energies from small ion/water droplets using common power-law functions of cluster size. We show that reliable estimates of these energies can be extrapolated from a small data set comprising the results of three droplets whose sizes are between 100 and 1000 using a basic power-law function of droplet size. This agrees with an earlier conclusion drawn from a model built within the mean spherical framework and paves the road toward a theoretical protocol to systematically compute the solvation energies of complex organic ions.

Exposure to common quaternary ammonium disinfectants decreases fertility in mice

PubMed Central

Melin, Vanessa E.; Potineni, Haritha; Hunt, Patricia; Griswold, Jodi; Siems, Bill; Werre, Stephen R.; Hrubec, Terry C.

2014-01-01

Quaternary ammonium compounds (QACs) are antimicrobial disinfectants commonly used in commercial and household settings. Extensive use of QACs results in ubiquitous human exposure, yet reproductive toxicity has not been evaluated. Decreased reproductive performance in laboratory mice coincided with the introduction of a disinfectant containing both alkyl dimethyl benzyl ammonium chloride (ADBAC) and didecyl dimethyl ammonium chloride (DDAC). QACs were detected in caging material over a period of several months following cessation of disinfectant use. Breeding pairs exposed for six months to a QAC disinfectant exhibited decreases in fertility and fecundity: increased time to first litter, longer pregnancy intervals, fewer pups per litter and fewer pregnancies. Significant morbidity in near term dams was also observed. In summary, exposure to a common QAC disinfectant mixture significantly impaired reproductive health in mice. This study illustrates the importance of assessing mixture toxicity of commonly used products whose components have only been evaluated individually. PMID:25483128

A Mathematical Relationship for Hydromorphone Loading into Liposomes with Trans-Membrane Ammonium Sulfate Gradients

PubMed Central

TU, SHENG; MCGINNIS, TAMARA; KRUGNER-HIGBY, LISA; HEATH, TIMOTHY D.

2014-01-01

We have studied the loading of the opioid hydromorphone into liposomes using ammonium sulfate gradients. Unlike other drugs loaded with this technique, hydromorphone is freely soluble as the sulfate salt, and, consequently, does not precipitate in the liposomes after loading. We have derived a mathematical relationship that can predict the extent of loading based on the ammonium ion content of the liposomes and the amount of drug added for loading. We have adapted and used the Berthelot indophenol assay to measure the amount of ammonium ions in the liposomes. Plots of the inverse of the fraction of hydromorphone loaded versus the amount of hydromorphone added are linear, and the slope should be the inverse of the amount of ammonium ions present in the liposomes. The inverse of the slopes obtained closely correspond to the amount of ammonium ions in the liposomes measured with the Berthelot indophenol assay. We also show that loading can be less than optimal under conditions where osmotically driven loss of ammonium ions or leakage of drug after loading may occur. PMID:20014429

A novel route to recognizing quaternary ammonium cations using electrospray mass spectrometry.

PubMed

Shackman, Holly M; Ding, Wei; Bolgar, Mark S

2015-01-01

Characterizing and elucidating structures is a commonplace and necessary activity in the pharmaceutical industry with mass spectrometry and NMR being the primary tools for analysis. Although many functional groups are readily identifiable, quaternary ammonium cations have proven to be difficult to unequivocally identify using these techniques. Due to the lack of an N-H bond, quaternary ammonium groups can only be detected in the (1)H NMR spectra by weak signals generated from long-range (14)N-H coupling, which by themselves are inconclusive evidence of a quaternary ammonium functional group. Due to their low intensity, these signals are frequently not detected. Additionally, ions cannot be differentiated in a mass spectrum as an M(+) or [M + H](+) ion without prior knowledge of the compound's structure. In order to utilize mass spectrometry as a tool for determining this functionality, ion cluster formation of quaternary ammonium cations and non-quaternary amines was studied using electrospray ionization. Several mobile phase modifiers were compared; however, the addition of small amounts of trifluoroacetic acid proved superior in producing characteristic and intense [M +2TFA](-) clusters for compounds containing quaternary ammonium cations when using negative electrospray. By fragmenting this characteristic ion using CID, nearly all compounds studied could be unambiguously identified as containing a quaternary ammonium cation or a non-quaternary amine attributable to the presence (non-quaternary amine) or absence (quaternary ammonium cation) of the resulting [2TFA + H](-) ion in the product spectra. This method of analysis provides a rapid, novel, and reliable technique for indicating the presence of quaternary ammonium cations in order to aid in structural elucidation.

A case of fatal intoxication with ammonium sulfate and a toxicological study using rabbits.

PubMed

Sato, A; Gonmori, K; Yoshioka, N

1999-04-26

Agricultural fertilizers such as ammonium sulfate are widely used in house gardens as well as in agriculture, but few case reports or toxicological studies of ingested fertilizers have been reported. This paper investigates a fatal case of ammonium sulfate poisoning and demonstrates its clinical and biochemical findings in rabbits. An 85-year-old woman was found dead lying on the ground outside her house in the middle of March, but the autopsy could not determine the cause of her death. Examination at the police laboratory of the solution in the beer can found next to her showed that it was very likely ammonium sulfate. Our measurement showed a significant increase of ammonium and sulfate ions in serum and gastric contents. The cause of her death was determined as poisoning by ammonium sulfate. The total dose of 1500 mg/kg of ammonium sulfate was administered to three rabbits, all of which showed similar symptoms such as mydriasis, irregular respiratory rhythms, local and general convulsions, until they fell into respiratory failure with cardiac arrest. EEG showed slow, suppressive waves and high-amplitude slowing wave pattern, which is generally observed clinically in hyperammonemia in man and animal. There was a remarkable increase in the concentration of ammonium ion and inorganic sulfate ion in serum, and blood gas analysis showed severe metabolic acidosis. These results, mainly findings by EEG, have shown that a rapid increase in ammonium ions in blood can cause damaging the central nervous system without microscopic change. When the cause of death can not be determined, measurement of ammonium ion, inorganic ion and electrolytes in blood as well as in stomach contents at forensic autopsy is necessary.

A mathematical relationship for hydromorphone loading into liposomes with trans-membrane ammonium sulfate gradients.

PubMed

Tu, Sheng; McGinnis, Tamara; Krugner-Higby, Lisa; Heath, Timothy D

2010-06-01

We have studied the loading of the opioid hydromorphone into liposomes using ammonium sulfate gradients. Unlike other drugs loaded with this technique, hydromorphone is freely soluble as the sulfate salt, and, consequently, does not precipitate in the liposomes after loading. We have derived a mathematical relationship that can predict the extent of loading based on the ammonium ion content of the liposomes and the amount of drug added for loading. We have adapted and used the Berthelot indophenol assay to measure the amount of ammonium ions in the liposomes. Plots of the inverse of the fraction of hydromorphone loaded versus the amount of hydromorphone added are linear, and the slope should be the inverse of the amount of ammonium ions present in the liposomes. The inverse of the slopes obtained closely correspond to the amount of ammonium ions in the liposomes measured with the Berthelot indophenol assay. We also show that loading can be less than optimal under conditions where osmotically driven loss of ammonium ions or leakage of drug after loading may occur. (c) 2009 Wiley-Liss, Inc. and the American Pharmacists Association

Ion exchange materials, method of forming ion exchange materials, and methods of treating liquids

DOEpatents

Wertsching, Alan K.; Peterson, Eric S.; Wey, John E.

2007-12-25

The invention includes an ion affinity material having an organic component which is sulfonated and which is chemically bonded to an inorganic substrate component. The invention includes a method of forming a metal binding material. A solid support material comprising surface oxide groups is provided and an organic component having at least one alkyl halide is covalently linked to at least some of the surface oxide groups to form a modified support material. The at least one alkyl halide is subsequently converted into an alkyl sulfonate. The invention further includes a method and system for extracting ions from a liquid. An ion exchange material having a sulfonated alkyl silane component covalently bonded to a metal oxide support material is provided and a liquid is exposed to the ion exchange material.

A comparison of the solvation structure and dynamics of the lithium ion in linear organic carbonates with different alkyl chain lengths.

PubMed

Fulfer, K D; Kuroda, D G

2017-09-20

The structure and dynamics of electrolytes composed of lithium hexafluorophosphate (LiPF 6 ) in dimethyl carbonate, ethyl methyl carbonate, and diethyl carbonate were investigated using a combination of linear and two-dimensional infrared spectroscopies. The solutions studied here have a LiPF 6 concentration of X(LiPF 6 ) = 0.09, which is typically found in commercial lithium ion batteries. This study focuses on comparing the differences in the solvation shell structure and dynamics produced by linear organic carbonates of different alkyl chain lengths. The IR experiments show that either linear carbonate forms a tetrahedral solvation shell (coordination number of 4) around the lithium ion irrespective of whether the solvation shell has anions in close proximity to the carbonates. Moreover, analysis of the absorption cross sections via FTIR and DFT computations reveals a distortion in the angle formed by Li + -O[double bond, length as m-dash]C which decreases from the expected 180° when the alkyl chains of the carbonate are lengthened. In addition, our findings also reveal that, likely due to its asymmetric structure, ethyl methyl carbonate has a significantly more distorted tetrahedral lithium ion solvation shell than either of the other two investigated carbonates. IR photon echo studies further demonstrate that the motions of the solvation shell have a time scale of a few picoseconds for all three linear carbonates. Interestingly, a slowdown of the in place-motions of the first solvation shell is observed when the carbonate has a longer alkyl chain length irrespective of the symmetry. In addition, vibrational energy transfer with a time scale of tens of picoseconds is observed between strongly coupled modes arising from the solvation shell structure of the Li + which corroborates the modeling of these solvation shells in terms of highly coupled vibrational states. Results of this study provide new insights into the molecular structure and dynamics of the

Identification of alkyl carbazoles and alkyl benzocarbazoles in Brazilian petroleum derivatives.

PubMed

Oliveira, Eniz Conceição; Vaz de Campos, Maria Cecília; Rodrigues, Maria Regina Alves; Pérez, Valéria Flores; Melecchi, Maria Inês Soares; Vale, Maria Goreti Rodrigues; Zini, Cláudia Alcaraz; Caramão, Elina Bastos

2006-02-10

Carbozoles are important compounds in crude oils, as they may be used as geochemical tracers, being the major type of nitrogen compounds in petroleum. At the same time, they are regarded as undesirable due to the problems they may cause in the refining process, such as catalyst poisoning, corrosion, gum or color formation in final products. As separation and identification of carbazoles are challenging goals, this work presents a chromatographic method, made of a pre-fractionation on neutral alumina followed by the separation and identification of two classes of carbazoles using FeCl(3)/Chromossorb W and gas chromatograph with mass spectrometer (GC/MS) (SIM-single ion monitoring mode) analysis. For the first time, a series of alkyl carbazoles and alkyl benzocarbazoles were identified in heavy gas oil (HGO) and atmospheric residue of distillation (ARD) obtained from Brazilian petroleum.

An empirical relation between the limiting ionic molar conductivities and self-diffusion coefficients of pure solvents

NASA Astrophysics Data System (ADS)

Matsuyama, Hisashi; Motoyoshi, Kota

2018-05-01

The limiting ionic molar conductivity (λ∞) of an electrolyte solution depends on the self-diffusion coefficient (Ds) of the pure solvent when the temperature (T) changes. To study the Ds-dependence of λ∞, we proposed a new empirical relation λ∞ ∝(Ds / T) t , with a parameter t. The relation is applied to the λ∞ and Ds of alkali, tetra-alkyl ammonium, and halogen ions in water or methanol. All ions except for tetra-alkyl ammonium ions in water exhibit excellent linear relationships in their λ∞ ∝(Ds / T) t plots, with t in the range from 0.88 to 1.26. This is the first report showing an affirmative linear correlation between λ∞ and Ds.

Understanding the effect of alkyl chains of gemini cations on the physicochemical and cellular properties of polyurethane micelles.

PubMed

Pan, Zhicheng; Fang, Danxuan; Song, Yuanqing; Song, Nijia; Ding, Mingming; Li, Jiehua; Luo, Feng; Li, Jianshu; Tan, Hong; Fu, Qiang

2018-06-06

Cationic gemini quaternary ammonium (GQA) has been used as a cell internalization promoter to improve the permeability of the cell membrane and enhance the cellular uptake. However, the effect of the alkyl chain length on the cellular properties of nanocarriers has not been elucidated yet. In this study, we developed a series of polyurethane micelles containing GQAs with various alkyl chain lengths. The alteration of the gemini alkyl chain length was found to change the distribution of GQA surfactants in the micellar structure and affect the surface charge exposure, stability, and the protein absorption properties of nanocarriers. Moreover, we also clarified the role of the alkyl chain length in tumor cell internalization and macrophage uptake of polyurethane micelles. This work provides a new understanding on the effect of the GQA alkyl chain length on the physicochemical and biological properties of nanomedicines, and offers guidance on the rational design of effective drug delivery systems where the issue of functional group exposure at the micellar surface should be considered.

Removal of ammonium from municipal landfill leachate using natural zeolites.

PubMed

Ye, Zhihong; Wang, Jiawen; Sun, Lingyu; Zhang, Daobin; Zhang, Hui

2015-01-01

Ammonium ion-exchange performance of the natural zeolite was investigated in both batch and column studies. The effects of zeolite dosage, contact time, stirring speed and pH on ammonium removal were investigated in batch experiments. The result showed that ammonium removal efficiency increased with an increase in zeolite dosage from 25 to 150 g/L, and an increase in stirring speed from 200 to 250 r/min. But further increase in zeolite dosage and stirring speed would result in an unpronounced increase of ammonium removal. The optimal pH for the removal of ammonium was found as 7.1. In the column studies, the effect of flow rate was investigated, and the total ammonium removal percentage during 180 min operation time decreased with the flow rate though the ion-exchange capacity varied to a very small extent with the flow rate ranging from 4 to 9 mL/min. The spent zeolite was regenerated by sodium chloride solution and the ammonia removal capacity of zeolite changed little or even increased after three regeneration cycles.

Induced binding of proteins by ammonium sulfate in affinity and ion-exchange column chromatography.

PubMed

Arakawa, Tsutomu; Tsumoto, Kouhei; Ejima, Daisuke; Kita, Yoshiko; Yonezawa, Yasushi; Tokunaga, Masao

2007-04-10

In general, proteins bind to affinity or ion-exchange columns at low salt concentrations, and the bound proteins are eluted by raising the salt concentration, changing the solvent pH, or adding competing ligands. Blue-Sepharose is often used to remove bovine serum albumin (BSA) from samples, but when we applied BSA to Blue-Sepharose in 20 mM phosphate, pH 7.0, 50%-60% of the protein flowed through the column; however, complete binding of BSA was achieved by the addition of 2 M ammonium sulfate (AS) to the column equilibration buffer and the sample. The bound protein was eluted by decreasing the AS concentration or by adding 1 M NaCl or arginine. AS at high concentrations resulted in binding of BSA even to an ion-exchange column, Q-Sepharose, at pH 7.0. Thus, although moderate salt concentrations elute proteins from Blue-Sepharose or ion-exchange columns, proteins can be bound to these columns under extreme salting-out conditions. Similar enhanced binding of proteins by AS was observed with an ATP-affinity column.

Extraction of manganese by alkyl monocarboxylic acid in a mixed extractant from a leaching solution of spent lithium-ion battery ternary cathodic material

NASA Astrophysics Data System (ADS)

Joo, Sung-Ho; Shin, Dongju; Oh, ChangHyun; Wang, Jei-Pil; Shin, Shun Myung

2016-02-01

We investigate the separation of manganese by an antagonistic effect from a leaching solution of ternary cathodic material of spent lithium-ion batteries that contain 11,400 mg L-1 Co, 11,700 mg L-1 Mn, 12,200 mg L-1 Ni, and 5300 mg L-1 Li using a mixture of alkyl monocarboxylic acid and di-(2-ethylhexyl)phosphoric acid extractants. pH isotherm, distribution coefficient, separation factor, McCabe-Thiele diagram, selective scrubbing, and countercurrent extraction tests are carried out to prove an antagonistic effect and to recover manganese using alkyl monocarboxylic in the mixed extractant. Slope analysis is used to determine the extraction mechanism between a mixture of extractants and valuable metals. An increasing concentration of alkyl monocarboxylic acid in the mixture of extractants results in a decrease in distribution coefficient of cobalt and manganese, however, the separation factor value (β(Mn/Co)) increases at pH 4.5. This is caused by slope analysis where alkyl monocarboxylic acid disrupts the extraction mechanism between di-(2-ethylhexyl)phosphoric acid and cobalt. Finally, continuous countercurrent extraction in a mini-plant test demonstrate the feasibility of manganese recovery from cobalt, nickel, and lithium.

Effect of polyoxyethylene n-alkyl ethers on carrier-mediated transport of lanthanide ions through cellulose triacetate membranes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sugiura, Masaaki

1992-02-01

Fluxes of 14 kinds of lanthanides across cellulose triacetate membranes were determined by using mixtures of o-nitrophenyl n-octyl ether and a series of polyoxythylene n-alkyl ethers (POE ethers) as plasticizers, and hinokitiol as carrier. Effects of alkyl and polyoxyethylene (POE) chains of POE ether on the flux were demonstrated. The transport of the lanthanides was coupled to a flow of hydrogen ions. The POE ethers used (C{sub n}H{sub 2n+1}(OCH{sub 2}CH{sub 2}){sub x}OH, referred to as C{sub n}E{sub x}) were C{sub 10}E{sub 3}, C{sub 12}E{sub 3}, C{sub 14}E{sub 3}, C{sub 16}E{sub 3}, C{sub 12}E{sub 2}, C{sub 12}E{sub 4}, C{sub 12}E{sub 6}more » and C{sub 12}E{sub 8}, In all cases, high fluxes were observed for the lanthanides from samarium to lutetium. On the contrary, the fluxes for lanthanum to neodymium were extremely low. In experiments testing the effect of the alkyl chain, the order of the POE ethers in the lanthanide flux for samarium to lutetium was C{sub 12}E{sub 3} > C{sub 10}E{sub 3} > C{sub 14}E{sub 3} >C{sub 16}E{sub 3}. In experiments testing the effect of the POE chain, the flux decreased with an increase in the chain length.« less

Determination of anionic surfactants during wastewater recycling process by ion pair chromatography with suppressed conductivity detection

NASA Technical Reports Server (NTRS)

Levine, L. H.; Judkins, J. E.; Garland, J. L.; Sager, J. C. (Principal Investigator)

2000-01-01

A direct approach utilizing ion pairing reversed-phase chromatography coupled with suppressed conductivity detection was developed to monitor biodegradation of anionic surfactants during wastewater recycling through hydroponic plant growth systems and fixed-film bioreactors. Samples of hydroponic nutrient solution and bioreactor effluent with high concentrations (up to 120 mS electrical conductance) of inorganic ions can be analyzed without pretreatment or interference. The presence of non-ionic surfactants did not significantly affect the analysis. Dynamic linear ranges for tested surfactants [Igepon TC-42, ammonium lauryl sulfate, sodium laureth sulfate and sodium alkyl (C10-C16) ether sulfate] were 2 to approximately 500, 1 to approximately 500, 2.5 to approximately 550 and 3.0 to approximately 630 microg/ml, respectively.

Effect of Fe3O4 addition on removal of ammonium by zeolite NaA.

PubMed

Liu, Haibo; Peng, Shuchuan; Shu, Lin; Chen, Tianhu; Bao, Teng; Frost, Ray L

2013-01-15

Magnetic zeolite NaA with different Fe(3)O(4) loadings was prepared by hydrothermal synthesis based on metakaolin and Fe(3)O(4). The effect of added Fe(3)O(4) on the removal of ammonium by zeolite NaA was investigated by varying the Fe(3)O(4) loading, pH, adsorption temperature, initial concentration, adsorption time. Langmuir, Freundlich, and pseudo-second-order modeling were used to describe the nature and mechanism of ammonium ion exchange using both zeolite and magnetic zeolite. Thermodynamic parameters such as change in Gibbs free energy, enthalpy and entropy were calculated. The results show that all the selected factors affect the ammonium ion exchange by zeolite and magnetic zeolite, however, the added Fe(3)O(4) apparently does not affect the ion exchange performance of zeolite to the ammonium ion. Freundlich model provides a better description of the adsorption process than Langmuir model. Moreover, kinetic analysis indicates the exchange of ammonium on the two materials follows a pseudo-second-order model. Thermodynamic analysis makes it clear that the adsorption process of ammonium is spontaneous and exothermic. Regardless of kinetic or thermodynamic analysis, all the results suggest that no considerable effect on the adsorption of the ammonium ion by zeolite is found after the addition of Fe(3)O(4). According to the results, magnetic zeolite NaA can be used for the removal of ammonium due to the good adsorption performance and easy separation method from aqueous solution. Copyright © 2012 Elsevier Inc. All rights reserved.

Mechanism of Phenol Alkylation in Zeolite H-BEA Using In Situ Solid-State NMR Spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhao, Zhenchao; Shi, Hui; Wan, Chuan

Alkylation of phenolic compounds in the liquid phase is of fundamental and practical importance to the conversion of biomass-derived feedstocks into fuels and chemicals. In this work, the reaction mechanism for phenol alkylation with cyclohexanol and cyclohexene has been investigated on a commercial HBEA zeolite by in situ 13C MAS NMR, using decalin as the solvent. From the variable temperature 13C MAS NMR measurements of phenol and cyclohexanol adsorption on HBEA from decalin solutions, it is shown that the two molecules have similar adsorption strength in the HBEA pore. Phenol alkylation with cyclohexanol, however, becomes significantly measurable only after cyclohexanolmore » is largely converted to cyclohexene via dehydration. This is in contrast to the initially rapid alkylation of phenol when using cyclohexene as the co-reactant. 13C isotope scrambling results demonstrate that the electrophile, presumably cyclohexyl carbenium ion, is directly formed in a protonation step when cyclohexene is the co-reactant, but requires re-adsorption of the alcohol dehydration product, cyclohexene, when cyclohexanol dimer is the dominant surface species (e.g., at 0.5 M cyclohexanol concentration) that is unable to generate carbenium ion. At the initial reaction stage of phenol-cyclohexanol alkylation on HBEA, the presence of the cyclohexanol dimer species hinders the adsorption of cyclohexene at the Brønsted acid site and the subsequent activation of the more potent electrophile (carbenium ion). Isotope scrambling data also show that intramolecular rearrangement of cyclohexyl phenyl ether, the O-alkylation product, does not significantly contribute to the formation of C-alkylation products.« less

A Theoretical Study of the Mechanism of the Alkylation of Guanine by N- Nitroso Compounds.

DTIC Science & Technology

1992-01-01

Later, Loveless isolated an 0 6 - methylated product from treatment with MNU and was the first to suggest a relevance of O6 alkylation 11 to the...replication. The ultimate metabolite involved in the alkylation reaction has generally been thought to be an alkyldiazonium ion or, its decomposition... Methylation of Formamide by the Methyldiazonium Ion .................... 60 Table 3.10: Intrinsic Barriers for Degenerate SN 2 Reactions .......... 66 Table

Ionic liquid containing hydroxamate and N-alkyl sulfamate ions

DOEpatents

Friesen, Cody A.; Wolfe, Derek; Johnson, Paul Bryan

2016-03-15

Embodiments of the invention are related to ionic liquids and more specifically to ionic liquids used in electrochemical metal-air cells in which the ionic liquid includes a cation and an anion selected from hydroxamate and/or N-alkyl sulfamate anions.

40 CFR 721.6540 - Acrylamide, polymers with tetraalkyl ammonium salt and polyalkyl, aminoalkyl meth-a-cryl-a-mide...

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Acrylamide, polymers with tetraalkyl... CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.6540 Acrylamide, polymers... as acrylamide, polymers with tetraalkyl ammonium salt and poly-al-kyl, amino alkyl meth-a-cryl-a-mide...

40 CFR 721.6540 - Acrylamide, polymers with tetraalkyl ammonium salt and polyalkyl, aminoalkyl meth-a-cryl-a-mide...

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Acrylamide, polymers with tetraalkyl... CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.6540 Acrylamide, polymers... as acrylamide, polymers with tetraalkyl ammonium salt and poly-al-kyl, amino alkyl meth-a-cryl-a-mide...

40 CFR 721.6540 - Acrylamide, polymers with tetraalkyl ammonium salt and polyalkyl, aminoalkyl meth-a-cryl-a-mide...

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Acrylamide, polymers with tetraalkyl... CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.6540 Acrylamide, polymers... as acrylamide, polymers with tetraalkyl ammonium salt and poly-al-kyl, amino alkyl meth-a-cryl-a-mide...

40 CFR 721.6540 - Acrylamide, polymers with tetraalkyl ammonium salt and polyalkyl, aminoalkyl meth-a-cryl-a-mide...

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Acrylamide, polymers with tetraalkyl... CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.6540 Acrylamide, polymers... as acrylamide, polymers with tetraalkyl ammonium salt and poly-al-kyl, amino alkyl meth-a-cryl-a-mide...

40 CFR 721.6540 - Acrylamide, polymers with tetraalkyl ammonium salt and polyalkyl, aminoalkyl meth-a-cryl-a-mide...

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Acrylamide, polymers with tetraalkyl... CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.6540 Acrylamide, polymers... as acrylamide, polymers with tetraalkyl ammonium salt and poly-al-kyl, amino alkyl meth-a-cryl-a-mide...

Determination of ammonium ion using a reagentless amperometric biosensor based on immobilized alanine dehydrogenase.

PubMed

Tan, Ling Ling; Musa, Ahmad; Lee, Yook Heng

2011-01-01

The use of the enzyme alanine dehydrogenase (AlaDH) for the determination of ammonium ion (NH(4)(+)) usually requires the addition of pyruvate substrate and reduced nicotinamide adenine dinucleotide (NADH) simultaneously to effect the reaction. This addition of reagents is inconvenient when an enzyme biosensor based on AlaDH is used. To resolve the problem, a novel reagentless amperometric biosensor using a stacked methacrylic membrane system coated onto a screen-printed carbon paste electrode (SPE) for NH(4)(+) ion determination is described. A mixture of pyruvate and NADH was immobilized in low molecular weight poly(2-hydroxyethyl methacrylate) (pHEMA) membrane, which was then deposited over a photocured pHEMA membrane (photoHEMA) containing alanine dehydrogenase (AlaDH) enzyme. Due to the enzymatic reaction of AlaDH and the pyruvate substrate, NH(4)(+) was consumed in the process and thus the signal from the electrocatalytic oxidation of NADH at an applied potential of +0.55 V was proportional to the NH(4)(+) ion concentration under optimal conditions. The stacked methacrylate membranes responded rapidly and linearly to changes in NH(4)(+) ion concentrations between 10-100 mM, with a detection limit of 0.18 mM NH(4)(+) ion. The reproducibility of the amperometrical NH(4)(+) biosensor yielded low relative standard deviations between 1.4-4.9%. The stacked membrane biosensor has been successfully applied to the determination of NH(4)(+) ion in spiked river water samples without pretreatment. A good correlation was found between the analytical results for NH(4)(+) obtained from the biosensor and the Nessler spectrophotometric method.

Surface Structures Formed by a Copper(II) Complex of Alkyl-Derivatized Indigo

PubMed Central

Honda, Akinori; Noda, Keisuke; Tamaki, Yoshinori; Miyamura, Kazuo

2016-01-01

Assembled structures of dyes have great influence on their coloring function. For example, metal ions added in the dyeing process are known to prevent fading of color. Thus, we have investigated the influence of an addition of copper(II) ion on the surface structure of alkyl-derivatized indigo. Scanning tunneling microscope (STM) analysis revealed that the copper(II) complexes of indigo formed orderly lamellar structures on a HOPG substrate. These lamellar structures of the complexes are found to be more stable than those of alkyl-derivatized indigos alone. Furthermore, 2D chirality was observed. PMID:28773957

Influence of Ammonium Ions, Organic Load and Flow Rate on the UV/Chlorine AOP Applied to Effluent of a Wastewater Treatment Plant at Pilot Scale.

PubMed

Rott, Eduard; Kuch, Bertram; Lange, Claudia; Richter, Philipp; Minke, Ralf

2018-06-16

This work investigates the influence of ammonium ions and the organic load (chemical oxygen demand (COD)) on the UV/chlorine AOP regarding the maintenance of free available chlorine (FAC) and elimination of 16 emerging contaminants (ECs) from wastewater treatment plant effluent (WWTE) at pilot scale (UV chamber at 0.4 kW). COD inhibited the FAC maintenance in the UV chamber influent at a ratio of 0.16 mg FAC per mg COD ( k HOCl⁻COD = 182 M −1 s −1 ). An increase in ammonium ion concentration led to a stoichiometric decrease of the FAC concentration in the UV chamber influent. Especially in cold seasons due to insufficient nitrification, the ammonium ion concentration in WWTE can become so high that it becomes impossible to achieve sufficiently high FAC concentrations in the UV chamber influent. For all ECs, the elimination effect by the UV/combined Cl₂ AOP (UV/CC) was not significantly higher than that by sole UV treatment. Accordingly, the UV/chlorine AOP is very sensitive and loses its effectiveness drastically as soon as there is no FAC but only CC in the UV chamber influent. Therefore, within the electrical energy consumption range tested (0.13⁻1 kWh/m³), a stable EC elimination performance of the UV/chlorine AOP cannot be maintained throughout the year.

Physicochemical properties and ion-solvent interactions in aqueous sodium, ammonium, and lead acetate solution

NASA Astrophysics Data System (ADS)

Deosarkar, S. D.; Mendkudle, M. S.

2014-09-01

Densities (ρ), viscosities (η) and refractive indices ( n D) of aqueous sodium acetate (SA), ammonium acetate (AA), and lead acetate (LA) solutions have been measured for different concentrations of salts at 302.15 K. Apparent molar volumes (φv) for studied solutions were calculated from density data, and fitted to Masson's relation and partial molar volume (φ{v/o}) was determined. Viscosity data were fitted to Jones-Dole equation and viscosity A- and B-coefficients were determined. Refractive index and density data were fitted to Lorentz and Lorenz equation and specific refraction ( R D) were calculated. Behavior of various physicochemical properties indicated presence of strong ion-solvent interactions in present systems and the acetate salts structure maker in water.

Specific ion effects on membrane potential and the permselectivity of ion exchange membranes.

PubMed

Geise, Geoffrey M; Cassady, Harrison J; Paul, Donald R; Logan, Bruce E; Hickner, Michael A

2014-10-21

Membrane potential and permselectivity are critical parameters for a variety of electrochemically-driven separation and energy technologies. An electric potential is developed when a membrane separates electrolyte solutions of different concentrations, and a permselective membrane allows specific species to be transported while restricting the passage of other species. Ion exchange membranes are commonly used in applications that require advanced ionic electrolytes and span technologies such as alkaline batteries to ammonium bicarbonate reverse electrodialysis, but membranes are often only characterized in sodium chloride solutions. Our goal in this work was to better understand membrane behaviour in aqueous ammonium bicarbonate, which is of interest for closed-loop energy generation processes. Here we characterized the permselectivity of four commercial ion exchange membranes in aqueous solutions of sodium chloride, ammonium chloride, sodium bicarbonate, and ammonium bicarbonate. This stepwise approach, using four different ions in aqueous solution, was used to better understand how these specific ions affect ion transport in ion exchange membranes. Characterization of cation and anion exchange membrane permselectivity, using these ions, is discussed from the perspective of the difference in the physical chemistry of the hydrated ions, along with an accompanying re-derivation and examination of the basic equations that describe membrane potential. In general, permselectivity was highest in sodium chloride and lowest in ammonium bicarbonate solutions, and the nature of both the counter- and co-ions appeared to influence measured permselectivity. The counter-ion type influences the binding affinity between counter-ions and polymer fixed charge groups, and higher binding affinity between fixed charge sites and counter-ions within the membrane decreases the effective membrane charge density. As a result permselectivity decreases. The charge density and polarizability

Determination of low-molecular-weight amines and ammonium in saline waters by ion chromatography after their extraction by steam distillation.

PubMed

Ferreira, Fernanda Nunes; Afonso, Julio Carlos; Pontes, Fernanda Veronesi Marinho; Carneiro, Manuel Castro; Neto, Arnaldo Alcover; Tristão, Maria Luiza Bragança; Monteiro, Maria Inês Couto

2016-04-01

A new method was developed for the determination of ammonium ion, monomethylamine and monoethylamine in saline waters by ion chromatography. Steam distillation was used to eliminate matrix interferences. Variables such as distillation time, concentration of sodium hydroxide solution and analyte mass were optimized by using a full two-level factorial (2(3) ) design. The influence of steam distillation on the analytical curves prepared in different matrices was also investigated. Limits of detection of 0.03, 0.05 and 0.05 mg/L were obtained for ammoniumion, monomethylamine and monoethylamine, respectively. Saline water samples from the Brazilian oil industry, containing sodium and potassium concentrations between 2.0-5.2% w/v and 96-928 mg/L, respectively, were analyzed. Satisfactory recoveries (90-105%) of the analytes were obtained for all spiked samples, and the precision was ≤ 7% (n = 3). The proposed method is adequate for analyzing saline waters containing sodium to ammoniumion, monomethylamine and monoethylamine concentration ratios up to 28 000:1 and potassium to ammonium, monomethylamine and monoethylamine concentration ratios up to 12 000:1. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Removal of ammonium from aqueous solutions with volcanic tuff.

PubMed

Marañón, E; Ulmanu, M; Fernández, Y; Anger, I; Castrillón, L

2006-10-11

This paper presents kinetic and equilibrium data concerning ammonium ion uptake from aqueous solutions using Romanian volcanic tuff. The influence of contact time, pH, ammonium concentration, presence of other cations and anion species is discussed. Equilibrium isotherms adequately fit the Langmuir and Freundlich models. The results showed a contact time of 3h to be sufficient to reach equilibrium and pH of 7 to be the optimum value. Adsorption capacities of 19 mg NH(4)(+)/g were obtained in multicomponent solutions (containing NH(4)(+), Zn(2+), Cd(2+), Ca(2+), Na(2+)). The presence of Zn and Cd at low concentrations did not decrease the ammonium adsorption capacity. Comparison of Romanian volcanic tuff with synthetic zeolites used for ammonium removal (5A, 13X and ZSM-5) was carried out. The removal efficiciency of ammonium by volcanic tuff were similar to those of zeolites 5A and 13X at low initial ammonium concentration, and much higher than those of zeolite ZSM-5.

Tertiary and Quaternary Ammonium-Phosphate Ionic Liquids as Lubricant Additives

DOE PAGES

Barnhill, William C.; Luo, Huimin; Meyer, III, Harry M; ...

2016-06-23

In this work we investigated the feasibility of five quaternary (aprotic) and four tertiary (protic) ammonium ionic liquids (ILs) with an identical organophosphate anion as lubricant antiwear additives. Viscosity, oil solubility, thermal stability, and corrosivity of the candidate ILs were characterized and correlated to the molecular structure. The protic group exhibits higher oil solubility than the aprotic group, and longer alkyl chains seem to provide better oil solubility and higher thermal stability. Selected ILs were applied as oil additives in steel-cast iron tribological tests and demonstrated promising anti-scuffing and anti-wear functionality. The thickness, nanostructure, coverage and composition of the tribofilmmore » formed by the besting performing IL were revealed by surface characterization for mechanistic understanding of the tribochemical interactions between the IL and metal surface. Results provide fundamental insights of the correlations among the molecular structure, physiochemical properties and lubricating performance for ammonium-phosphate ILs.« less

Tertiary and Quaternary Ammonium-Phosphate Ionic Liquids as Lubricant Additives

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barnhill, William C.; Luo, Huimin; Meyer, III, Harry M

In this work we investigated the feasibility of five quaternary (aprotic) and four tertiary (protic) ammonium ionic liquids (ILs) with an identical organophosphate anion as lubricant antiwear additives. Viscosity, oil solubility, thermal stability, and corrosivity of the candidate ILs were characterized and correlated to the molecular structure. The protic group exhibits higher oil solubility than the aprotic group, and longer alkyl chains seem to provide better oil solubility and higher thermal stability. Selected ILs were applied as oil additives in steel-cast iron tribological tests and demonstrated promising anti-scuffing and anti-wear functionality. The thickness, nanostructure, coverage and composition of the tribofilmmore » formed by the besting performing IL were revealed by surface characterization for mechanistic understanding of the tribochemical interactions between the IL and metal surface. Results provide fundamental insights of the correlations among the molecular structure, physiochemical properties and lubricating performance for ammonium-phosphate ILs.« less

Base-Free Photoredox/Nickel Dual-Catalytic Cross-Coupling of Ammonium Alkylsilicates.

PubMed

Jouffroy, Matthieu; Primer, David N; Molander, Gary A

2016-01-20

Single-electron transmetalation is recognized as an enabling technology for the mild transfer of alkyl groups to transition metal catalysts in cross-coupling reactions. Hypercoordinate silicates represent a new and improved class of radical precursors because of their low oxidation potentials and the innocuous byproducts generated upon oxidation. Herein, we report the cross-coupling of secondary and primary ammonium alkylsilicates with (hetero)aryl bromides in good to excellent yields. The base-free conditions have exceptional protic group tolerance on both partners, permitting the cross-coupling of unprotected primary and secondary amines.

Alkyl–Alkyl Suzuki Cross-Couplings of Unactivated Secondary Alkyl Chlorides**

PubMed Central

Lu, Zhe; Fu, Gregory C.

2010-01-01

The first method for achieving alkyl–alkyl Suzuki reactions of unactivated secondary alkyl chlorides has been developed. Carbon–carbon bond formation occurs under mild conditions (at room temperature) with the aid of commercially available catalyst components. This method has proved to be versatile: without modification, it can be applied to Suzuki reactions of secondary and primary alkyl bromides and iodides, as well as primary alkyl chlorides. Mechanistic investigations suggest that oxidative addition is not the turnover-limiting step of the catalytic cycle for unactivated secondary alkyl iodides and bromides, whereas it may be (partially) for chlorides. PMID:20715038

Effect of alkyl branches on the thermal stability of quaternary ammonium cations in organic electrolytes for electrochemical double layer capacitors.

PubMed

Ahn, Yong Nam; Lee, Sung Hoon; Lee, Goo Soo; Kim, Hyunbin

2017-08-02

Quaternary ammoniums are cations having widespread use in organic electrolytes for high performance electrochemical double layer capacitors (EDLCs) due to their various advantages such as high electrochemical stability and inexpensive production cost. However, the decomposition of quaternary ammoniums via Hofmann elimination hinders their applications for EDLCs operating at elevated temperatures. This study systematically investigates the reactivity of four different quaternary ammoniums (tetraethyl-, triethylmethyl-, diethyldimethyl-, and trimethylethyl-ammonium) in EDLC by utilizing density functional theory calculations and Brownian dynamics simulations complemented with molecular dynamics simulations. It is found that ammonium stability reduces upon increasing the number of ethyl branches that have a stronger positive charge than the methyl groups. However, the contribution of the entropy change to the reaction free energy makes trimethylethylammonium less stable than diethyldimethylammonium at room temperature although the former has less ethyl branches than the latter. Trimethylethylammonium becomes the most stable at a high temperature of 488 K above which the activation free energy becomes effectively negligible and thus the number of reactive sites determines the overall stability. The fundamental understanding of the ammonium decompositions through Hofmann elimination demonstrated in this study is expected to contribute to developing new long-life organic electrolyte systems for high-temperature applications.

Removal of mercury (II), elemental mercury and arsenic from simulated flue gas by ammonium sulphide.

PubMed

Ning, Ping; Guo, Xiaolong; Wang, Xueqian; Wang, Ping; Ma, Yixing; Lan, Yi

2015-01-01

A tubular resistance furnace was used as a reactor to simulate mercury and arsenic in smelter flue gases by heating mercury and arsenic compounds. The flue gas containing Hg(2+), Hg(0) and As was treated with ammonium sulphide. The experiment was conducted to investigate the effects of varying the concentration of ammonium sulphide, the pH value of ammonium sulphide, the temperature of ammonium sulphide, the presence of SO2 and the presence of sulphite ion on removal efficiency. The prepared adsorption products were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy and scanning electron microscopy. The results showed that the optimal concentration of ammonium sulphide was 0.8 mol/L. The optimal pH value of ammonium sulphide was 10, and the optimal temperature of ammonium sulphide was 20°C.Under the optimum conditions, the removal efficiency of Hg(2+), Hg(0) and As could reach 99%, 88.8%, 98%, respectively. In addition, SO2 and sulphite ion could reduce the removal efficiency of mercury and arsenic from simulated flue gas.

Ammonium nitrate-polymer glasses: a new concept for phase and thermal stabilization of ammonium nitrate.

PubMed

Lang, Anthony J; Vyazovkin, Sergey

2008-09-11

Dissolving of ammonium nitrate in highly polar polymers such as poly(vinylpyrrolidone) and/or poly(acrylamide) can result in the formation of single-phase glassy solid materials, in which NH 4 (+) and NO 3 (-) are separated through an ion-dipole interaction with the polymer matrix. Below the glass transition temperature of the polymer matrix the resulting materials remain phase and thermally stable as demonstrated through the absence of decomposition as well as the solid-solid transitions and melting of ammonium nitrate. The structure of the materials is explored by Fourier transform infrared spectroscopy and density functional calculations. Differential scanning calorimetry, thermogravimetry, and isoconversional kinetic analysis are applied to characterize the thermal behavior of the materials.

Effect of simulated acid rain on nitrate and ammonium production in soils from three ecosystems of Camels Hump Mountain, Vermont

DOE Office of Scientific and Technical Information (OSTI.GOV)

Like, D.E.; Klein, R.M.

1985-11-01

The authors removed intact soil columns from the Harwood (550 to 790 m), Transition (790 to 1050 m), and Conifer (1050 to 1160 m) ecological zones of Camels Hump Mountain, Vermont, treated them with simulated acid rain (pH 4.0) or nonacidic (pH 5.6) rain, and examined the percolates for ammonium and nitrate ions. Nitrification in soils from all three ecosystems was unaffected by acidic treatments, but mineralization was stimulated by acidic treatment of soil from the Transition Zone. Irrespective of treatment, Conifer Zone soils released less nitrate than did either Transition or Hardwood Zone soils. Soil columns from the Hardwoodmore » Zone were treated with acidic or nonacidic simulated rainfall supplemented with nitrate, ammonium, or both N sources. NO3-N in percolates increased when acidic simulated rain was supplemented with ammonium ion or both ammonium and nitrate ions. Efflux of NH4-N was unaffected by supplementing precipitation with either ammonium or nitrate ions.« less

Analysis of an explosion accident of nitrogen trichloride in a waste liquid containing ammonium ion and platinum black.

PubMed

Okada, Ken; Akiyoshi, Miyako; Ishizaki, Keiko; Sato, Hiroyasu; Matsunaga, Takehiro

2014-08-15

Five liters of sodium hypochlorite aqueous solution (12 mass%) was poured into 300 L of liquid waste containing ammonium ion of about 1.8 mol/L in a 500 L tank in a plant area; then, two minutes later the solution exploded with a flash on March 30th, 2005. The tank cover, the fluorescent lamp and the air duct were broken by the blast wave. Thus, we have conducted 40 runs of laboratory-scale explosion tests under various conditions (solution concentrations of (NH4)2SO4 and NaClO, temperatures, Pt catalysts, pH, etc.) to investigate the causes for such an explosion. When solutions of ammonium sulfate and sodium hypochlorite are mixed in the presence of platinum black, explosions result. This is ascribable to the formation of explosive nitrogen trichloride (NCl3). In the case where it is necessary to mix these 2 solutions (ammonium sulfate and sodium hypochlorite) in the presence of platinum black, the following conditions would reduce a probability of explosion; the initial concentration of NH4(+) should be less than 3 mol/L and the pH should be higher than 6. The hypochlorite solution (in 1/10 in volume) to be added at room temperature is recommended to be less than 0.6 mol/L. Copyright © 2014 Elsevier B.V. All rights reserved.

Hydrolysis of p-nitrophenyl esters promoted by semifluorinated quaternary ammonium polymer latexes and films.

PubMed

Kaur, Baljinder; McBride, Sean P; Paul, Abhijit; Ford, Warren T

2010-10-19

Semifluorinated polymer latexes were prepared by emulsion polymerization of 2.5-25% of a fluoroalkyl methacrylate, 25% chloromethylstyrene, 1% styrylmethyl(trimethyl)ammonium chloride, and the remainder 2-ethylhexyl methacrylate under surfactant-free conditions. The chloromethylstyrene units were converted to quaternary ammonium ions with trimethylamine. In aqueous dispersions at particle concentrations of less than 1 mg mL(-1) the quaternary ammonium ion latexes promoted hydrolyses of p-nitrophenyl hexanoate (PNPH) in pH 9.4 borate buffer and of diethyl p-nitrophenyl phosphate (Paraoxon) in 0.1 M NaOH at 30 °C with half-lives of less than 10 min. Thin 0.7-2 μm films of the latexes on glass promoted fast hydrolysis of Paraoxon but not of PNPH under the same conditions. Even after annealing the quaternary ammonium ion polymer films at temperatures well above their glass transition temperatures, AFM images of the film surfaces had textures of particles. Contact angle measurements of the annealed films against water and against hexadecane showed that the surfaces were not highly fluorinated.

Determination of ammonium in river water and sewage samples by capillary zone electrophoresis with direct UV detection.

PubMed

Fukushi, Keiichi; Ito, Hideyuki; Kimura, Kenichi; Yokota, Kuriko; Saito, Keiitsu; Chayama, Kenji; Takeda, Sahori; Wakida, Shin-ichi

2006-02-17

We developed capillary zone electrophoresis (CZE) with direct UV detection for determination of ammonium in environmental water samples. Ammonium in the samples was partly converted into ammonia in the alkaline background electrolyte (BGE) during migration and was detected by molecular absorption of ammonia at 190 nm in approximately 7 min. The limit of detection (LOD) for ammonium was 0.24 mg/l (as nitrogen) at a signal-to-noise ratio of three. The respective values of the relative standard deviation (RSD) of peak area, peak height, and migration time for ammonium were 2.1, 1.8, and 0.46%. Major alkali and alkaline earth metal ions coexisting in the samples did not interfere with ammonium determination by the proposed method. The proposed method determined ammonium in surface water and sewage samples. The results were compared to those obtained using ion chromatography (IC).

40 CFR 721.9595 - Alkyl benzene sulfonic acids and alkyl sulfates, amine salts (generic).

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Alkyl benzene sulfonic acids and alkyl... Significant New Uses for Specific Chemical Substances § 721.9595 Alkyl benzene sulfonic acids and alkyl...) The chemical substances identified generically as alkyl benzene sulfonic acids and alkyl sulfates...

40 CFR 721.9595 - Alkyl benzene sulfonic acids and alkyl sulfates, amine salts (generic).

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Alkyl benzene sulfonic acids and alkyl... Significant New Uses for Specific Chemical Substances § 721.9595 Alkyl benzene sulfonic acids and alkyl...) The chemical substances identified generically as alkyl benzene sulfonic acids and alkyl sulfates...

40 CFR 721.9595 - Alkyl benzene sulfonic acids and alkyl sulfates, amine salts (generic).

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Alkyl benzene sulfonic acids and alkyl... Significant New Uses for Specific Chemical Substances § 721.9595 Alkyl benzene sulfonic acids and alkyl...) The chemical substances identified generically as alkyl benzene sulfonic acids and alkyl sulfates...

40 CFR 721.9595 - Alkyl benzene sulfonic acids and alkyl sulfates, amine salts (generic).

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Alkyl benzene sulfonic acids and alkyl... Significant New Uses for Specific Chemical Substances § 721.9595 Alkyl benzene sulfonic acids and alkyl...) The chemical substances identified generically as alkyl benzene sulfonic acids and alkyl sulfates...

40 CFR 721.9595 - Alkyl benzene sulfonic acids and alkyl sulfates, amine salts (generic).

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Alkyl benzene sulfonic acids and alkyl... Significant New Uses for Specific Chemical Substances § 721.9595 Alkyl benzene sulfonic acids and alkyl...) The chemical substances identified generically as alkyl benzene sulfonic acids and alkyl sulfates...

40 CFR 721.1875 - Boric acid, alkyl and substituted alkyl esters (generic name).

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Boric acid, alkyl and substituted... Significant New Uses for Specific Chemical Substances § 721.1875 Boric acid, alkyl and substituted alkyl... chemical substance boric acid, alkyl and substituted alkyl esters (PMN P-86-1252) is subject to reporting...

40 CFR 721.1875 - Boric acid, alkyl and substituted alkyl esters (generic name).

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Boric acid, alkyl and substituted... Significant New Uses for Specific Chemical Substances § 721.1875 Boric acid, alkyl and substituted alkyl... chemical substance boric acid, alkyl and substituted alkyl esters (PMN P-86-1252) is subject to reporting...

40 CFR 721.1875 - Boric acid, alkyl and substituted alkyl esters (generic name).

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Boric acid, alkyl and substituted... Significant New Uses for Specific Chemical Substances § 721.1875 Boric acid, alkyl and substituted alkyl... chemical substance boric acid, alkyl and substituted alkyl esters (PMN P-86-1252) is subject to reporting...

40 CFR 721.1875 - Boric acid, alkyl and substituted alkyl esters (generic name).

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Boric acid, alkyl and substituted... Significant New Uses for Specific Chemical Substances § 721.1875 Boric acid, alkyl and substituted alkyl... chemical substance boric acid, alkyl and substituted alkyl esters (PMN P-86-1252) is subject to reporting...

40 CFR 721.1875 - Boric acid, alkyl and substituted alkyl esters (generic name).

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Boric acid, alkyl and substituted... Significant New Uses for Specific Chemical Substances § 721.1875 Boric acid, alkyl and substituted alkyl... chemical substance boric acid, alkyl and substituted alkyl esters (PMN P-86-1252) is subject to reporting...

Quaternary ammonium-functionalized silica sorbents for the solid-phase extraction of aromatic amines under normal phase conditions.

PubMed

Vidal, Lorena; Robin, Orlane; Parshintsev, Jevgeni; Mikkola, Jyri-Pekka; Riekkola, Marja-Liisa

2013-04-12

Quaternary ammonium-functionalized silica materials were synthesized and applied for solid-phase extraction (SPE) of aromatic amines, which are classified as priority pollutants by US Environmental Protection Agency. Hexamethylenetetramine used for silica surface modification for the first time was employed as SPE sorbent under normal phase conditions. Hexaminium-functionalized silica demonstrated excellent extraction efficiencies for o-toluidine, 4-ethylaniline and quinoline (recoveries 101-107%), while for N,N-dimethylaniline and N-isopropylaniline recoveries were from low to moderate (14-46%). In addition, the suitability of 1-alkyl-3-(propyl-3-sulfonate) imidazolium-functionalized silica as SPE sorbent was tested under normal phase conditions. The recoveries achieved for the five aromatic amines ranged from 89 to 99%. The stability of the sorbent was evaluated during and after 150 extractions. Coefficients of variation between 4.5 and 10.2% proved a high stability of the synthesized sorbent. Elution was carried out using acetonitrile in the case of hexaminium-functionalized silica and water for 1-alkyl-3-(propyl-3-sulfonate) imidazolium-functionalized silica sorbent. After the extraction the analytes were separated and detected by liquid chromatography ultraviolet detection (LC-UV). The retention mechanism of the materials was primarily based on polar hydrogen bonding and π-π interactions. Comparison made with activated silica proved the quaternary ammonium-functionalized materials to offer different selectivity and better extraction efficiencies for aromatic amines. Finally, 1-alkyl-3-(propyl-3-sulfonate) imidazolium-functionalized silica sorbent was successfully tested for the extraction of wastewater and soil samples. Copyright © 2013 Elsevier B.V. All rights reserved.

Ammonium detection by formation of colored zebra-bands in a detecting tube.

PubMed

Hori, Tatsuaki; Niki, Keizou; Kiso, Yoshiaki; Oguchi, Tatsuo; Kamimoto, Yuki; Yamada, Toshiro; Nagai, Masahiro

2010-06-15

Ammonium ion was colorized by means of a diazo coupling reaction with 2-phenylphenol, where the color development reaction was conducted within 3min by using boric acid as a catalyst. The resulting colored solution (0.5ml) was supplied by suction to a detecting tube consisting of a nonwoven fabric test strip (2mm wide, 1mm thick, 150mm long) impregnated with benzylcetyldimethylammonium chloride in a stripe pattern and enclosed in a heat-shrinkable tube. When the colored solution was supplied to the detecting tube, blue zebra-bands formed, and the ammonium concentration was determined by counting the number of zebra-bands. The detection range was 1-20mg-Nl(-1). Ammonium ion in actual domestic wastewater samples was successfully detected by means of this method.

Ion chromatography with the indirect ultraviolet detection of alkali metal ions and ammonium using imidazolium ionic liquid as ultraviolet absorption reagent and eluent.

PubMed

Liu, Yong-Qiang; Yu, Hong

2016-08-01

Indirect ultraviolet detection was conducted in ultraviolet-absorption-agent-added mobile phase to complete the detection of the absence of ultraviolet absorption functional group in analytes. Compared with precolumn derivatization or postcolumn derivatization, this method can be widely used, has the advantages of simple operation and good linear relationship. Chromatographic separation of Li(+) , Na(+) , K(+) , and NH4 (+) was performed on a carboxylic acid base cation exchange column using imidazolium ionic liquid/acid/organic solvent as the mobile phase, in which imidazolium ionic liquids acted as ultraviolet absorption reagent and eluting agent. The retention behaviors of four kinds of cations are discussed, and the mechanism of separation and detection are described. The main factors influencing the separation and detection were the background ultraviolet absorption reagent and the concentration of hydrogen ion in the ion chromatography-indirect ultraviolet detection. The successful separation and detection of Li(+) , Na(+) , K(+) , and NH4 (+) within 13 min was achieved using the selected chromatographic conditions, and the detection limits (S/N = 3) were 0.02, 0.11, 0.30, and 0.06 mg/L, respectively. A new separation and analysis method of alkali metal ions and ammonium by ion chromatography with indirect ultraviolet detection method was developed, and the application range of ionic liquid was expanded. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ammonium removal from aqueous solutions by using natural Chinese (Chende) zeolite as adsorbent.

PubMed

Huang, Haiming; Xiao, Xianming; Yan, Bo; Yang, Liping

2010-03-15

This paper presents a study of the removal of ammonium ion from aqueous solutions using natural Chinese (Chende) zeolite. A series of experiments was conducted to examine the effects of solution pH, particle size, contact time, adsorbent dosage, and the presence of other cation- and anion species on ammonium removal. The findings indicated that these parameters named had a significant effect on the removal of ammonium by the zeolite. The effect of other cations on the removal of ammonium followed the order of preference Na(+)>K(+)>Ca(2+)>Mg(2+) at identical mass concentrations, and the effect of the presence of individual anions followed the order of preference carbonate>chloride>sulfate>phosphate at identical mass concentrations of ammonium ions. Kinetic analysis showed that the adsorption of ammonium on zeolite at different ranges of particle size well followed the pseudo-second-order model and followed the intra-particle diffusion model only during the initial 60 min of the adsorption process. Equilibrium isotherm data was fitted to the linear Langmuir- and Freundlich models with the latter model providing the better description of the process (R(2)=0.991-0.997) compared to the former (R(2)=0.902-0.989). (c) 2009 Elsevier B.V. All rights reserved.

Precipitation of ammonium from concentrated industrial wastes as struvite: a search for the optimal reagents.

PubMed

Borojovich, Eitan J C; Münster, Meshulam; Rafailov, Gennady; Porat, Ze'ev

2010-07-01

Precipitation of struvite (MgNH4PO4) is a known process for purification of wastewater from high concentrations of ammonium. The optimal conditions for precipitation are basic pH (around 9) and sufficient concentrations of magnesium and phosphate ions. In this work, we accomplished efficient precipitation of ammonium from concentrated industrial waste stream by using magnesium oxide (MgO) both as a source of magnesium ions and as a base. Best results were obtained with technical-grade MgO, which provided 99% removal of ammonium. Moreover, ammonium removal occurred already at pH 7, and the residual ammonium concentration (50 mg/L) remained constant upon addition of more MgO without rising again, as occurs with sodium hydroxide (NaOH). This process may have two other advantages; it also can be relevant for the problem of uncontrolled precipitation of struvite in the supernatant of anaerobic sludge treatment plants, and the precipitate can be used as a fertilizer.

Using 15N-Ammonium to Characterise and Map Potassium Binding Sites in Proteins by NMR Spectroscopy

PubMed Central

Werbeck, Nicolas D; Kirkpatrick, John; Reinstein, Jochen; Hansen, D Flemming

2014-01-01

A variety of enzymes are activated by the binding of potassium ions. The potassium binding sites of these enzymes are very specific, but ammonium ions can often replace potassium ions in vitro because of their similar ionic radii. In these cases, ammonium can be used as a proxy for potassium to characterise potassium binding sites in enzymes: the 1H,15N spin-pair of enzyme-bound 15NH4+ can be probed by 15N-edited heteronuclear NMR experiments. Here, we demonstrate the use of NMR spectroscopy to characterise binding of ammonium ions to two different enzymes: human histone deacetylase 8 (HDAC8), which is activated allosterically by potassium, and the bacterial Hsp70 homologue DnaK, for which potassium is an integral part of the active site. Ammonium activates both enzymes in a similar way to potassium, thus supporting this non-invasive approach. Furthermore, we present an approach to map the observed binding site onto the structure of HDAC8. Our method for mapping the binding site is general and does not require chemical shift assignment of the enzyme resonances. PMID:24520048

An operationally flexible fuel cell based on quaternary ammonium-biphosphate ion pairs

DOE PAGES

Lee, Kwan -Soo; Spendelow, Jacob Schatz; Choe, Yoong -Kee; ...

2016-08-22

Here, fuel cells are promising devices for clean power generation in a variety of economically and environmentally significant applications. Low-temperature proton exchange membrane (PEM) fuel cells utilizing Nafion require a high level of hydration, which limits the operating temperature to less than 100°C. In contrast, high-temperature PEM fuel cells utilizing phosphoric acid-doped polybenzimidazole can operate effectively up to 180°C; however, these devices degrade when exposed to water below 140°C. Here we present a different class of PEM fuel cells based on quaternary ammonium-biphosphate ion pairs that can operate under conditions unattainable with existing fuel cell technologies. These fuel cells exhibitmore » stable performance at 80–160°C with a conductivity decay rate more than three orders of magnitude lower than that of a commercial high-temperature PEM fuel cell. By increasing the operational flexibility, this class of fuel cell can simplify the requirements for heat and water management, and potentially reduce the costs associated with the existing fully functional fuel cell systems.« less

An operationally flexible fuel cell based on quaternary ammonium-biphosphate ion pairs

NASA Astrophysics Data System (ADS)

Lee, Kwan-Soo; Spendelow, Jacob S.; Choe, Yoong-Kee; Fujimoto, Cy; Kim, Yu Seung

2016-09-01

Fuel cells are promising devices for clean power generation in a variety of economically and environmentally significant applications. Low-temperature proton exchange membrane (PEM) fuel cells utilizing Nafion require a high level of hydration, which limits the operating temperature to less than 100 ∘C. In contrast, high-temperature PEM fuel cells utilizing phosphoric acid-doped polybenzimidazole can operate effectively up to 180 ∘C however, these devices degrade when exposed to water below 140 ∘C. Here we present a different class of PEM fuel cells based on quaternary ammonium-biphosphate ion pairs that can operate under conditions unattainable with existing fuel cell technologies. These fuel cells exhibit stable performance at 80-160 ∘C with a conductivity decay rate more than three orders of magnitude lower than that of a commercial high-temperature PEM fuel cell. By increasing the operational flexibility, this class of fuel cell can simplify the requirements for heat and water management, and potentially reduce the costs associated with the existing fully functional fuel cell systems.

Transition metal ion-assisted photochemical generation of alkyl halides and hydrocarbons from carboxylic acids.

PubMed

Carraher, Jack M; Pestovsky, Oleg; Bakac, Andreja

2012-05-21

Near-UV photolysis of aqueous solutions of propionic acid and aqueous Fe(3+) in the absence of oxygen generates a mixture of hydrocarbons (ethane, ethylene and butane), carbon dioxide, and Fe(2+). The reaction becomes mildly catalytic (about five turnovers) in the presence of oxygen which converts a portion of alkyl radicals to oxidizing intermediates that reoxidize Fe(2+). The photochemistry in the presence of halide ions (X(-) = Cl(-), Br(-)) generates ethyl halides via halogen atom abstraction from FeX(n)(3-n) by ethyl radicals. Near-quantitative yields of C(2)H(5)X are obtained at ≥0.05 M X(-). Competition experiments with Co(NH(3))(5)Br(2+) provided kinetic data for the reaction of ethyl radicals with FeCl(2+) (k = (4.0 ± 0.5) × 10(6) M(-1) s(-1)) and with FeBr(2+) (k = (3.0 ± 0.5) × 10(7) M(-1) s(-1)). Photochemical decarboxylation of propionic acid in the presence of Cu(2+) generates ethylene and Cu(+). Longer-chain acids also yield alpha olefins as exclusive products. These reactions become catalytic under constant purge with oxygen which plays a dual role. It reoxidizes Cu(+) to Cu(2+), and removes gaseous olefins to prevent accumulation of Cu(+)(olefin) complexes and depletion of Cu(2+). The results underscore the profound effect that the choice of metal ions, the medium, and reaction conditions exert on the photochemistry of carboxylic acids.

[Alkylating agents].

PubMed

Pourquier, Philippe

2011-11-01

With the approval of mechlorethamine by the FDA in 1949 for the treatment of hematologic malignancies, alkylating agents are the oldest class of anticancer agents. Even though their clinical use is far beyond the use of new targeted therapies, they still occupy a major place in specific indications and sometimes represent the unique option for the treatment of refractory diseases. Here, we are reviewing the major classes of alkylating agents and their mechanism of action, with a particular emphasis for the new generations of alkylating agents. As for most of the chemotherapeutic agents used in the clinic, these compounds are derived from natural sources. With a complex but original mechanism of action, they represent new interesting alternatives for the clinicians, especially for tumors that are resistant to conventional DNA damaging agents. We also briefly describe the different strategies that have been or are currently developed to potentiate the use of classical alkylating agents, especially the inhibition of pathways that are involved in the repair of DNA lesions induced by these agents. In this line, the development of PARP inhibitors is a striking example of the recent regain of interest towards the "old" alkylating agents.

Effect of fertilizer application on ammonia emission and concentration levels of ammonium, nitrate, and nitrite ions in a rice field.

PubMed

Das, Piw; Sa, Jae-Hwan; Kim, Ki-Hyun; Jeon, Eui-Chan

2009-07-01

The concentrations of ammonium NH4+, nitrate NO3-, and nitrite NO2- ions were recorded along with ammonia (NH(3)) emission from a fertilized rice field located in the Kwangju province in South Korea over a period of 4 months (June to October 2006). The highest magnitude of NH(3) flux was 20,754 microg m(-2) h(-1), while the average flux value over the entire sampling period was 2,395 microg m(-2) h(-1). The highest ionic concentrations were 1.67, 0.44, and 0.71 ppm for NH4+, NO3-, and NO2- ions, respectively. Possible effects of soil pH on NH(3) fluxes were detected, as they concurrently exhibited a gradual and periodic change during the sampling period. Positive correlations existed between concentrations of NH4+ and NO2- ions and the soil pH. Positive correlations also existed between NH(3) emission flux and ambient (and water) temperatures. Results indicated that fertilizer application to rice can lead to significant emission of NH(3) along with NH4+ and NO3- ions.

Aliphatic long chain quaternary ammonium compounds analysis by ion-pair chromatography coupled with suppressed conductivity and UV detection in lysing reagents for blood cell analysers.

PubMed

Giovannelli, D; Abballe, F

2005-08-26

A method has been developed which allows simultaneous determination of three linear alkyl trimethylammonium salts. Dodecyltrimethylammonium chloride, tetradecyltrimethylammonium bromide and hexadecyltrimethylammonium chloride are widely used as main active ingredients of lysing reagents for blood cell analyzers which perform white blood cells differential determination into two or more sub-populations by impedance analysis. The ion-pair on styrene-divinyl benzene chromatographic phase looks like a suitable, reliable and long term stable tool for separation of such quaternary compounds. The detection based on suppressed conductivity was chosen because of the lack of significance chromophores. A micromembrane suppressor device compatible with high solvent concentration (up to 80%) was used in order to minimize the conductivity background before the detection. In the present work we show how the chemical post column derivatization makes the alkyl chain detectable also by UV direct detection at 210 nm.

Properties of the Nafion membrane impregnated with hydroxyl ammonium based ionic liquids

NASA Astrophysics Data System (ADS)

Garaev, Valeriy; Kleperis, Janis; Pavlovica, Sanita; Vaivars, Guntars

2012-08-01

In this work, the Nafion 112 membrane impregnated with nine various hydroxyl ammonium based ionic liquids have been investigated. The used ionic liquids were combined from hydroxyl ammonium cations (2-hydroxyethylammonium/HEA, bis(2- hydroxyethyl)ammonium/BHEA, tris(2-hydroxyethyl)ammonium/THEA) and carboxylate anions (formate, acetate, lactate). The membranes are characterized by conductivity and thermal stability measurements. It was found, that almost all composites have 10 times higher ion conductivity than a pure Nafion 112 at 90 °C in ambient environment due to the higher thermal stability. The thermal stability of Nafion membrane was increased by all studied nine ionic liquids. In this work, only biodegradable ionic liquids were used for composite preparation.

DETERMINATION OF ALKYLATED & SULFONATED DIPHENYL OXIDE SULFACTANT BY HIGH PERFORMANCE LIQUID CHROMATOGRAPHY

EPA Science Inventory

Methods for the determination of the anionic surfactant Dowfax 8390 are described. Dowfax is a complex mixture of various alkylated and sulfonated diphenyl oxides. The primary component of Dowfax is monoalkylated disulfonated diphenyl oxide (MADS). This work uses ion pairing chro...

Modifying Silicates for Better Dispersion in Nanocomposites

NASA Technical Reports Server (NTRS)

Campbell, Sandi

2005-01-01

An improved chemical modification has been developed to enhance the dispersion of layered silicate particles in the formulation of a polymer/silicate nanocomposite material. The modification involves, among other things, the co-exchange of an alkyl ammonium ion and a monoprotonated diamine with interlayer cations of the silicate. The net overall effects of the improved chemical modification are to improve processability of the nanocomposite and maximize the benefits of dispersing the silicate particles into the polymer. Some background discussion is necessary to give meaning to a description of this development. Polymer/silicate nanocomposites are also denoted polymer/clay composites because the silicate particles in them are typically derived from clay particles. Particles of clay comprise layers of silicate platelets separated by gaps called "galleries." The platelet thickness is 1 nm. The length varies from 30 nm to 1 m, depending on the silicate. In order to fully realize the benefits of polymer/silicate nanocomposites, it is necessary to ensure that the platelets become dispersed in the polymer matrices. Proper dispersion can impart physical and chemical properties that make nanocomposites attractive for a variety of applications. In order to achieve nanometer-level dispersion of a layered silicate into a polymer matrix, it is typically necessary to modify the interlayer silicate surfaces by attaching organic functional groups. This modification can be achieved easily by ion exchange between the interlayer metal cations found naturally in the silicate and protonated organic cations - typically protonated amines. Long-chain alkyl ammonium ions are commonly chosen as the ion-exchange materials because they effectively lower the surface energies of the silicates and ease the incorporation of organic monomers or polymers into the silicate galleries. This completes the background discussion. In the present improved modification of the interlayer silicate surfaces

46 CFR 148.205 - Ammonium nitrate and ammonium nitrate fertilizers.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 5 2011-10-01 2011-10-01 false Ammonium nitrate and ammonium nitrate fertilizers. 148... Materials § 148.205 Ammonium nitrate and ammonium nitrate fertilizers. (a) This section applies to the stowage and transportation in bulk of ammonium nitrate and the following fertilizers composed of uniform...

46 CFR 148.205 - Ammonium nitrate and ammonium nitrate fertilizers.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 5 2014-10-01 2014-10-01 false Ammonium nitrate and ammonium nitrate fertilizers. 148... Materials § 148.205 Ammonium nitrate and ammonium nitrate fertilizers. (a) This section applies to the stowage and transportation in bulk of ammonium nitrate and the following fertilizers composed of uniform...

46 CFR 148.205 - Ammonium nitrate and ammonium nitrate fertilizers.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 5 2012-10-01 2012-10-01 false Ammonium nitrate and ammonium nitrate fertilizers. 148... Materials § 148.205 Ammonium nitrate and ammonium nitrate fertilizers. (a) This section applies to the stowage and transportation in bulk of ammonium nitrate and the following fertilizers composed of uniform...

46 CFR 148.205 - Ammonium nitrate and ammonium nitrate fertilizers.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 5 2013-10-01 2013-10-01 false Ammonium nitrate and ammonium nitrate fertilizers. 148... Materials § 148.205 Ammonium nitrate and ammonium nitrate fertilizers. (a) This section applies to the stowage and transportation in bulk of ammonium nitrate and the following fertilizers composed of uniform...

Highly Stable, Anion Conductive, Comb-Shaped Copolymers for Alkaline Fuel Cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, NW; Leng, YJ; Hickner, MA

2013-07-10

To produce an anion-conductive and durable polymer electrolyte for alkaline fuel cell applications, a series of quaternized poly(2,6-dimethyl phenylene oxide)s containing long alkyl side chains pendant to the nitrogen-centered cation were synthesized using a Menshutkin reaction to form comb-shaped structures. The pendant alkyl chains were responsible for the development of highly conductive ionic domains, as confirmed by small-angle X-ray scattering (SAXS). The comb-shaped polymers having one alkyl side chain showed higher hydroxide conductivities than those with benzyltrimethyl ammonium moieties or structures with more than one alkyl side chain per cationic site. The highest conductivity was observed for comb-shaped polymers withmore » benzyldimethylhexadecyl ammonium cations. The chemical stabilities of the comb-shaped membranes were evaluated under severe, accelerated-aging conditions, and degradation was observed by measuring IEC and ion conductivity changes during aging. The comb-shaped membranes retained their high ion conductivity in 1 M NaOH at 80 degrees C for 2000 h. These cationic polymers were employed as ionomers in catalyst layers for alkaline fuel cells. The results indicated that the C-16 alkyl side chain ionomer had a slightly better initial performance, despite its low IEC value, but very poor durability in the fuel cell. In contrast, 90% of the initial performance was retained for the alkaline fuel cell with electrodes containing the C-6 side chain after 60 h of fuel cell operation.« less

Ion/Ion Reactions with "Onium" Reagents: An Approach for the Gas-phase Transfer of Organic Cations to Multiply-Charged Anions

NASA Astrophysics Data System (ADS)

Gilbert, Joshua D.; Prentice, Boone M.; McLuckey, Scott A.

2015-05-01

The use of ion/ion reactions to effect gas-phase alkylation is demonstrated. Commonly used fixed-charge "onium" cations are well-suited for ion/ion reactions with multiply deprotonated analytes because of their tendency to form long-lived electrostatic complexes. Activation of these complexes results in an SN2 reaction that yields an alkylated anion with the loss of a neutral remnant of the reagent. This alkylation process forms the basis of a general method for alkylation of deprotonated analytes generated via electrospray, and is demonstrated on a variety of anionic sites. SN2 reactions of this nature are demonstrated empirically and characterized using density functional theory (DFT). This method for modification in the gas phase is extended to the transfer of larger and more complex R groups that can be used in later gas-phase synthesis steps. For example, N-cyclohexyl- N'-(2-morpholinoethyl)carbodiimide (CMC) is used to transfer a carbodiimide functionality to a peptide anion containing a carboxylic acid. Subsequent activation yields a selective reaction between the transferred carbodiimide group and a carboxylic acid, suggesting the carbodiimide functionality is retained through the transfer process. Many different R groups are transferable using this method, allowing for new possibilities for charge manipulation and derivatization in the gas phase.

Alkylation effects on the energy transfer of highly vibrationally excited naphthalene.

PubMed

Hsu, Hsu Chen; Tsai, Ming-Tsang; Dyakov, Yuri A; Ni, Chi-Kung

2011-11-04

The energy transfer of highly vibrationally excited isomers of dimethylnaphthalene and 2-ethylnaphthalene in collisions with krypton were investigated using crossed molecular beam/time-of-flight mass spectrometer/time-sliced velocity map ion imaging techniques at a collision energy of approximately 300 cm(-1). Angular-resolved energy-transfer distribution functions were obtained directly from the images of inelastic scattering. The results show that alkyl-substituted naphthalenes transfer more vibrational energy to translational energy than unsubstituted naphthalene. Alkylation enhances the V→T energy transfer in the range -ΔE(d)=-100~-1500 cm(-1) by approximately a factor of 2. However, the maximum values of V→T energy transfer for alkyl-substituted naphthalenes are about 1500~2000 cm(-1), which is similar to that of naphthalene. The lack of rotation-like wide-angle motion of the aromatic ring and no enhancement in very large V→T energy transfer, like supercollisions, indicates that very large V→T energy transfer requires special vibrational motions. This transfer cannot be achieved by the low-frequency vibrational motions of alkyl groups. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Explicit hydration of ammonium ion by correlated methods employing molecular tailoring approach

NASA Astrophysics Data System (ADS)

Singh, Gurmeet; Verma, Rahul; Wagle, Swapnil; Gadre, Shridhar R.

2017-11-01

Explicit hydration studies of ions require accurate estimation of interaction energies. This work explores the explicit hydration of the ammonium ion (NH4+) employing Møller-Plesset second order (MP2) perturbation theory, an accurate yet relatively less expensive correlated method. Several initial geometries of NH4+(H2O)n (n = 4 to 13) clusters are subjected to MP2 level geometry optimisation with correlation consistent aug-cc-pVDZ (aVDZ) basis set. For large clusters (viz. n > 8), molecular tailoring approach (MTA) is used for single point energy evaluation at MP2/aVTZ level for the estimation of MP2 level binding energies (BEs) at complete basis set (CBS) limit. The minimal nature of the clusters upto n ≤ 8 is confirmed by performing vibrational frequency calculations at MP2/aVDZ level of theory, whereas for larger clusters (9 ≤ n ≤ 13) such calculations are effected via grafted MTA (GMTA) method. The zero point energy (ZPE) corrections are done for all the isomers lying within 1 kcal/mol of the lowest energy one. The resulting frequencies in N-H region (2900-3500 cm-1) and in O-H stretching region (3300-3900 cm-1) are in found to be in excellent agreement with the available experimental findings for 4 ≤ n ≤ 13. Furthermore, GMTA is also applied for calculating the BEs of these clusters at coupled cluster singles and doubles with perturbative triples (CCSD(T)) level of theory with aVDZ basis set. This work thus represents an art of the possible on contemporary multi-core computers for studying explicit molecular hydration at correlated level theories.

Alkyl substituent effects on gas-phase acidities - The influence of hybridization.

NASA Technical Reports Server (NTRS)

Brauman, J. I.; Blair, L. K.

1971-01-01

Exploration of the effect on acidity of alkyl groups bonded to trigonal and digonal carbon. Some results on the relative acidities of toluene and p-xylene, and acetylene and substitute acetylenes, as determined by ion cyclotron resonance (icr) spectroscopy, are described. Some limitations of the CNDO/2 calculation method are discussed.

Gas-Phase Oxidation via Ion/Ion Reactions: Pathways and Applications

NASA Astrophysics Data System (ADS)

Pilo, Alice L.; Zhao, Feifei; McLuckey, Scott A.

2017-06-01

Here, we provide an overview of pathways available upon the gas-phase oxidation of peptides and DNA via ion/ion reactions and explore potential applications of these chemistries. The oxidation of thioethers (i.e., methionine residues and S-alkyl cysteine residues), disulfide bonds, S-nitrosylated cysteine residues, and DNA to the [M+H+O]+ derivative via ion/ion reactions with periodate and peroxymono-sulfate anions is demonstrated. The oxidation of neutral basic sites to various oxidized structures, including the [M+H+O]+, [M-H]+, and [M-H-NH3]+ species, via ion/ion reactions is illustrated and the oxidation characteristics of two different oxidizing reagents, periodate and persulfate anions, are compared. Lastly, the highly efficient generation of molecular radical cations via ion/ion reactions with sulfate radical anion is summarized. Activation of the newly generated molecular radical peptide cations results in losses of various neutral side chains, several of which generate dehydroalanine residues that can be used to localize the amino acid from which the dehydroalanine was generated. The chemistries presented herein result in a diverse range of structures that can be used for a variety of applications, including the identification and localization of S-alkyl cysteine residues, the oxidative cleavage of disulfide bonds, and the generation of molecular radical cations from even-electron doubly protonated peptides. [Figure not available: see fulltext.

Removing ammonium from water and wastewater using cost-effective adsorbents: A review.

PubMed

Huang, Jianyin; Kankanamge, Nadeeka Rathnayake; Chow, Christopher; Welsh, David T; Li, Tianling; Teasdale, Peter R

2018-01-01

Ammonium is an important nutrient in primary production; however, high ammonium loads can cause eutrophication of natural waterways, contributing to undesirable changes in water quality and ecosystem structure. While ammonium pollution comes from diffuse agricultural sources, making control difficult, industrial or municipal point sources such as wastewater treatment plants also contribute significantly to overall ammonium pollution. These latter sources can be targeted more readily to control ammonium release into water systems. To assist policy makers and researchers in understanding the diversity of treatment options and the best option for their circumstance, this paper produces a comprehensive review of existing treatment options for ammonium removal with a particular focus on those technologies which offer the highest rates of removal and cost-effectiveness. Ion exchange and adsorption material methods are simple to apply, cost-effective, environmentally friendly technologies which are quite efficient at removing ammonium from treated water. The review presents a list of adsorbents from the literature, their adsorption capacities and other parameters needed for ammonium removal. Further, the preparation of adsorbents with high ammonium removal capacities and new adsorbents is discussed in the context of their relative cost, removal efficiencies, and limitations. Efficient, cost-effective, and environmental friendly adsorbents for the removal of ammonium on a large scale for commercial or water treatment plants are provided. In addition, future perspectives on removing ammonium using adsorbents are presented. Copyright © 2017. Published by Elsevier B.V.

Preparation of immunoglobulin Y from egg yolk using ammonium sulfate precipitation and ion exchange chromatography.

PubMed

Ko, K Y; Ahn, D U

2007-02-01

The objective of this study was to develop an economical, simple, and large-scale separation method for IgY from egg yolk. Egg yolk diluted with 9 volumes of cold water was centrifuged after adjusting the pH to 5.0. The supernatant was added with 0.01% charcoal or 0.01% carrageenan and centrifuged at 2,800 x g for 30 min. The supernatant was filtered through a Whatman no. 1 filter paper and then the filtrate was concentrated to 20% original volume using ultrafiltration. The concentrated solution was further purified using either cation exchange chromatography or ammonium sulfate precipitation. For the cation exchange chromatography method, the concentrated sample was loaded onto a column equilibrated with 20 mM citrate-phosphate buffer at pH 4.8 and eluted with 200 mM citrate-phosphate buffer at pH 6.4. For the ammonium sulfate precipitation method, the concentrated sample was twice precipitated with 40% ammonium sulfate solution at pH 9.0. The yield and purity of IgY were determined by ELISA and electrophoresis. The yield of IgY from the cation exchange chromatography method was 30 to 40%, whereas that of the ammonium sulfate precipitation was 70 to 80%. The purity of IgY from the ammonium sulfate method was higher than that of the cation exchange chromatography. The cation exchange chromatography could handle only a small amount of samples, whereas the ammonium sulfate precipitation could handle a large volume of samples. This suggests that ammonium sulfate precipitation was a more efficient and useful purification method than cation exchange chromatography for the large-scale preparation of IgY from egg yolk.

Phase transition in lithium ammonium sulphate doped with cesium metal ions

NASA Astrophysics Data System (ADS)

Gaafar, M.; Kassem, M. E.; Kandil, S. H.

2000-07-01

Effects of doped cesium (C s+) metal ions (with different molar ratios n) on the phase transition of lithium ammonium sulphate LiNH 4SO 4 system have been studied by measuring the specific heat Cp( T) of the doped systems in the temperature range from 400 to 480 K. The study shows a peculiar phase transition of the pure system ( n=0) characterized by double distinct peaks, changed to a single sharp and narrow one as a result of the doping process. The measurements exhibit different effects of enhanced molar ratios of dopants on the phase transition behaviour of this system. At low dopant content ( n≤3%), the excess specific heat (Δ Cp) max at the transition temperature T1 decreases till a minimum value at n=0.8%, then it increases gradually. In this case, Δ Cp( T) behaviour is varied quantitatively and not modified. Enhanced dopant content ( n>3%) has a pronounced effect on the critical behaviour, which is significantly changed and considerably modified relative to the pure system. In addition, broadening of the critical temperature region, and decrease of (Δ Cp) max associated with changes of the Landau expansion coefficients are obtained and discussed. The study deals with the contribution of the thermally excited dipoles to the specific heat in the ferroelectric region and shows that their energy depends on doping.

Removal of ammonium and heavy metals by cost-effective zeolite synthesized from waste quartz sand and calcium fluoride sludge.

PubMed

Zhang, Qian; Lin, Bing; Hong, Junming; Chang, Chang-Tang

2017-02-01

This study focuses on the effectiveness of zeolite (10% CF-Z [0.5]) hydrothermally synthesized from waste quartz sand and calcium fluoride (CF) for ammonium ion and heavy metal removal. Zeolite was characterized through powder X-ray diffraction, Fourier-transform infrared spectroscopy, micromeritics N 2 adsorption/desorption analysis, and field emission scanning electron microscopy. The effects of CF addition, Si/Al ratio, initial ammonium concentration, solution pH, and temperature on the adsorption of ammonium on 10% CF-Z (0.5) were further examined. Results showed that 10% CF-Z (0.5) was a single-phase zeolite A with cubic-shaped crystals and 10% CF-Z (0.5) efficiently adsorbs ammonium and heavy metals. For instance, 91% ammonium (10 mg L -1 ) and 93% lead (10 mg L -1 ) are removed. The adsorption isotherm, kinetics, and thermodynamics of ammonium adsorption on 10% CF-Z (0.5) were also theoretically analyzed. The adsorption isotherm of ammonium and lead on 10% CF-Z (0.5) in single systems indicated that Freundlich model provides the best fit for the equilibrium data, whereas pseudo-second-order model best describes the adsorption kinetics. The adsorption degree of ions on 10% CF-Z (0.5) in mixed systems exhibits the following pattern: lead > ammonium > cadmium > chromium.

The Scarlet Letter of Alkylation: A Mini Review of Selective Alkylating Agents

PubMed Central

Oronsky, Bryan T; Reid, Tony; Knox, Susan J; Scicinski, Jan J

2012-01-01

If there were a stigma scale for chemotherapy, alkylating agents would be ranked at the top of the list. The chemical term alkylation is associated with nonselective toxicity, an association that dates back to the use of nitrogen mustards during World War I as chemical warfare agents. That this stigma persists and extends to compounds that, through selectivity, attempt to “tame” the indiscriminate destructive potential of alkylation is the subject of this review. Selective alkylation, as it is referred to herein, constitutes an extremely nascent and dynamic field in oncology. The pharmacodynamic response to this selective strategy depends on a delicate kinetic balance between specificity and the rate and extent of binding. Three representative compounds are presented: RRx-001, 3-bromopyruvate, and TH-302. The main impetus for the development of these compounds has been the avoidance of the serious complications of traditional alkylating agents; therefore, it is the thesis of this review that they should not experience stigma by association. PMID:22937173

Gas chromatography-mass spectrometric studies of O-alkyl O-2-(N,N-dialkylamino) ethyl alkylphosphonites(phosphonates) for chemical weapons convention verification.

PubMed

Saeidian, Hamid; Babri, Mehran; Ramezani, Atefeh; Ashrafi, Davood; Sarabadani, Mansour; Naseri, Mohammad Taghi

2013-01-01

The electron ionization (EI) mass spectra of a series of O-alkyl O-2-(N,N-dialkylaminolethyl alkylphosphonites(phosphonates), which are precursors of nerve agents, were studied for Chemical Weapons Convention (CWC) verification. General El fragmentation pathways were constructed and discussed. Proposed fragment structures were confirmed through analyzing fragment ions of deuterated analogs and density functional theory (DFT) calculations. The observed fragment ions are due to different fragmentation pathways such as hydrogen and McLafferty+1 rearrangements, alkene, amine and alkoxy elimination by alpha- or beta-cleavage process. Fragment ions distinctly allow unequivocal identification of the interested compounds including those of isomeric compounds. The presence and abundance of fragment ions were found to depend on the size and structure of the alkyl group attached to nitrogen, phosphorus and oxygen atoms.

Synthesis of prostaglandins by conjugate addition and alkylation of a directed enolate ion. 4,5-allenyl prostaglandins

DOE Office of Scientific and Technical Information (OSTI.GOV)

Patterson, J.W.

1990-09-28

Over the previous two decades many elegant syntheses of prostaglandins, which in more sophisticated forms, allow the stereospecific introduction of the various asymmetric carbons have been accomplished. However, among these approaches the cuprate addition/enolate alkylation of suitable cyclopentenone {sup 2} stands out because of brevity and convergence. The recent reports by Noyori{sup 3} and Corey{sup 4} and their colleagues have reduced to practice the conversion of 4-alkoxycyclopentenones to prostaglandin E{sub 2} (PGE{sub 2}) by conjugate addition of an organocopper derivative of the lower side chain followed by alkylation of the resulting carbanion with methyl 7-halohept-2-enoate. The subject of this papermore » is application of the Tardella tin enolate alkylation developed by Noyori to the synthesis of 4, 5-allenic prostaglandins, a pharmacologically important class of compounds. The authors results demonstrate that the tandem alkylation of an enone precursor with a cuprate reagent followed by alkylation of the corresponding tin enolate with bromide reagent is a viable synthetic method for 4,5-didehydro-PGE{sub 2}. Because the optically active forms of 1 and the vinyl iodide precursor of the PGE{sub 2} lower side chain have been employed to produce a single enantiomer of PGE{sub 2}, the extension of the methodology described here to the synthesis of single enantiomers of 4a awaits only the preparation of the separate enantiomers of allene 14.« less

Simultaneous removal of ammonium and phosphate by alkaline-activated and lanthanum-impregnated zeolite.

PubMed

He, Yinhai; Lin, Hai; Dong, Yingbo; Liu, Quanli; Wang, Liang

2016-12-01

Simultaneous ammonium and phosphate removal characteristics and mechanism, as well as the major influencing factors, such as pH, temperature and co-existing ions, onto NaOH-activated and lanthanum-impregnated zeolite (NLZ) were investigated. The phosphate adsorption increases from 0.2 mg g -1 for natural zeolite up to 8.96 mg g -1 for NLZ, while only a slight decrease on the ammonium adsorption capacity from 23.9 mg g -1 for NaOH-activated zeolite to 21.2 mg g -1 for NLZ was observed. The ammonium and phosphate adsorption showed little pH dependence in the range from pH 3 to 7, while it decreased sharply with the pH increased above pH 7. Adsorption of ammonium and phosphate could be well described by the pseudo-second-order model and the process was mainly governed by intra-particle diffusion. The Langmuir and Freundlich model can be acceptably applied to fit the experimental data, which suggested that adsorption was caused by both the monolayer and homogeneous coverage at specific and equal affinity sites available NLZ. The underlying mechanism for the specific adsorption of phosphate by NLZ was revealed with the aid of SEM-EDS, XPS, and FTIR analysis, and the formation of (LaO)(OH)PO 2 was verified to be the dominant pathway for selective phosphate adsorption by lanthanum-impregnated zeolite. While the removal mechanism of ammonium could be well interpreted by SEM-EDS, FTIR and ICP analysis, and ion-exchange was expected to be the main removal process for ammonium. The results indicate that NLZ could efficiently and simultaneously remove low concentration of ammonium and phosphate from contaminated waters. Copyright © 2016 Elsevier Ltd. All rights reserved.

Discovery of the ammonium substrate site on glutamine synthetase, a third cation binding site.

PubMed Central

Liaw, S. H.; Kuo, I.; Eisenberg, D.

1995-01-01

Glutamine synthetase (GS) catalyzes the ATP-dependent condensation of ammonia and glutamate to yield glutamine, ADP, and inorganic phosphate in the presence of divalent cations. Bacterial GS is an enzyme of 12 identical subunits, arranged in two rings of 6, with the active site between each pair of subunits in a ring. In earlier work, we have reported the locations within the funnel-shaped active site of the substrates glutamate and ATP and of the two divalent cations, but the site for ammonia (or ammonium) has remained elusive. Here we report the discovery by X-ray crystallography of a binding site on GS for monovalent cations, Tl+ and Cs+, which is probably the binding site for the substrate ammonium ion. Fourier difference maps show the following. (1) Tl+ and Cs+ bind at essentially the same site, with ligands being Glu 212, Tyr 179, Asp 50', Ser 53' of the adjacent subunit, and the substrate glutamate. From its position adjacent to the substrate glutamate and the cofactor ADP, we propose that this monovalent cation site is the substrate ammonium ion binding site. This proposal is supported by enzyme kinetics. Our kinetic measurements show that Tl+, Cs+, and NH4+ are competitive inhibitors to NH2OH in the gamma-glutamyl transfer reaction. (2) GS is a trimetallic enzyme containing two divalent cation sites (n1, n2) and one monovalent cation site per subunit. These three closely spaced ions are all at the active site: the distance between n1 and n2 is 6 A, between n1 and Tl+ is 4 A, and between n2 and Tl+ is 7 A. Glu 212 and the substrate glutamate are bridging ligands for the n1 ion and Tl+. (3) The presence of a monovalent cation in this site may enhance the structural stability of GS, because of its effect of balancing the negative charges of the substrate glutamate and its ligands and because of strengthening the "side-to-side" intersubunit interaction through the cation-protein bonding. (4) The presence of the cofactor ADP increases the Tl+ binding to GS

Anti-Caries Effects of Dental Adhesives Containing Quaternary Ammonium Methacrylates with Different Chain Lengths

PubMed Central

Han, Qi; Li, Bolei; Zhou, Xuedong; Ge, Yang; Wang, Suping; Li, Mingyun; Ren, Biao; Wang, Haohao; Zhang, Keke; Xu, Hockin H. K.; Peng, Xian; Feng, Mingye; Weir, Michael D.; Chen, Yu; Cheng, Lei

2017-01-01

The objectives of this study were to investigate the effects of dental adhesives containing quaternary ammonium methacrylates (QAMs) with different alkyl chain lengths (CL) on ecological caries prevention in vitro. Five QAMs were synthesized with a CL = 3, 6, 9, 12, and 16 and incorporated into adhesives. Micro-tensile bond strength and surface charge density were used to measure the physical properties of the adhesives. The proportion change in three-species biofilms consisting of Streptococcus mutans, Streptococcus sanguinis, and Streptococcus gordonii was tested using the TaqMan real-time polymerase chain reaction. Lactic acid assay, MTT [3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay, exopolysaccharide staining, live/dead staining, scanning electron microscopy (SEM), and transverse microradiography (TMR) were performed to study the anti-biofilm and anti-demineralization effects of the dental adhesives. The results showed that incorporating QAMs with different alkyl chain lengths into the adhesives had no obvious effect on the dentin bond strength. The adhesives containing QAMs with a longer alkyl chain developed healthier biofilms. The surface charge density, anti-biofilm, and anti-demineralization effects of the adhesives increased with a CL of the QAMs from 3 to 12, but decreased slightly with a CL from 12 to 16. In conclusion, adhesives containing QAMs with a tailored chain length are promising for preventing secondary caries in an “ecological way”. PMID:28773004

A practical derivatization LC/MS approach for determination of trace level alkyl sulfonates and dialkyl sulfates genotoxic impurities in drug substances.

PubMed

An, Jianguo; Sun, Mingjiang; Bai, Lin; Chen, Ted; Liu, David Q; Kord, Alireza

2008-11-04

Derivatization LC/MS methodology has been developed for the determination of a group of commonly encountered alkyl esters of sulfonates or sulfates in drug substances at low ppm levels. This general method uses trimethylamine as the derivatizing reagent for ethyl/propyl/isopropyl esters and triethylamine for methyl esters. The resulting quaternary ammonium derivatization products are highly polar (ionic) and can be retained by a hydrophilic interaction liquid chromatography (HILIC) column and readily separated from the main interfering active pharmaceutical ingredient (API) peak that is usually present at very high concentration. The method gives excellent sensitivity for all the alkyl esters at typical target analyte level of 1-2 ppm when the API samples were prepared at 5mg/mL. The recoveries at 1-2 ppm were generally above 85% for all the alkyl esters in the various APIs tested. The injection precisions of the lowest concentration standards were excellent with R.S.D.=0.4-4%. A linear range for concentrations from 0.2 to 20 ppm has been established with R(2)>or=0.99. This general method has been tested in a number of API matrices and used successfully for determination of alkyl sulfonates or dialkyl sulfates in support of API batch releases at GlaxoSmithKline.

Determination of ammonium ion by fluorometry or spectrophotometry after on-line derivatization with o-phthalaldehyde

NASA Technical Reports Server (NTRS)

Goyal, S. S.; Rains, D. W.; Huffaker, R. C.

1988-01-01

A fast, sensitive, simple, and highly reproducible method for routine assay of ammonium ion (NH4+) was developed by using HPLC equipment. The method is based on the reaction of NH4+ with o-phthalaldehyde (OPA) in the presence of 2-mercaptoethanol. After an on-line derivatization, the resulting NH4(+)-OPA product was quantified by using fluorometric or spectrophotometric detection. For fluorometric detection, the excitation and emission wavelengths were 410 and 470 nm, respectively. The spectrophotometric detection was made by measuring absorbance at 410 nm. Results on the effects of OPA-reagent composition and pH, reaction temperature, sample matrix, and linearity of the assay are presented. Even though it took about 2 min from the time of sample injection to the appearance of sample peak, sample injections could be overlapped at an interval of about 1 min. Thus, the actual time needed for analysis was about 1 min per assay. The method can be used in a fully automated mode by using an autosampler injector.

Quantitative remote sensing of ammonium minerals, Cedar Mountains, Esmeralda County, Nevada

NASA Technical Reports Server (NTRS)

Baugh, William M.; Kruse, Fred A.

1995-01-01

Mineral-bound ammonium (NH4+) was discovered by the U.S. Geological Survey in the southern Cedar Mountains of Esmeralda County, Nevada in 1989. At 10 km in length, this site is 100 times larger than any previously known occurrence in volcanic rocks. The ammonium occurs in two hydrothermally altered, crystal-rich rhyolitic tuff units of Oligocene age, and is both structurally and stratigraphically controlled. This research uses Advanced Visible/Infrared Imaging Spectrometer (AVIRIS) data to quantitatively map the mineral-bound ammonium (buddingtonite) concentration in the altered volcanic rocks. Naturally occurring mineral-bound ammonium is fairly rare; however, it has been found to occur in gold-bearing hydrothermal deposits. Because of this association, it is thought that ammonium may be a useful too in exploration for gold and other metal deposits. Mineral-bound ammonium is produced when an ammonium ion (NH4+) replaces the alkali cation site (usually K+) in the crystal structure of silicate minerals such as feldspars, micas and clays. Buddingtonite is an ammonium feldspar. The ammonium originates in buried organic plant matter and is transported to the host rock by hydrothermal fluids. Ammonium alteration does not produce visible changes in the rock, and it is barely detectable with standard x-ray diffraction methods. It is clearly identified, however, by absorption features in short wave-infrared (SWIR) wavelengths (2.0 - 2.5 micrometers). The ammonium absorption features are believed to be caused by N-H vibrational modes and are analogous to hydroxyl (O-H) vibrational modes, only shifted slightly in wavelength. Buddingtonite absorption features in the near- and SWIR lie at 1.56, 2.02 and 2.12 micrometers. The feature at 2.12 micrometer is the strongest of the three and is the only one used in this study. The southern Cedar Mountains are sparsely vegetated and are an ideal site for a remote sensing study.

Random quaternary ammonium Diels-Alder poly(phenylene) copolymers for improved vanadium redox flow batteries

NASA Astrophysics Data System (ADS)

Largier, Timothy D.; Cornelius, Chris J.

2017-06-01

This study analyzes the effect of quaternary ammonium homopolymer (AmPP) and ionic and non-ionic random unit copolymerization (AmPP-PP) of Diels-Alder poly(phenylene)s on electrochemical and transport properties, vanadium redox flow battery performance, and material stability. AmPP-PP materials were synthesized with IEC's up to 2.2 meq/g, displaying a carbonate form ion conductivity of 17.3 mS/cm and water uptake of 57.3%. Vanadium ion permeability studies revealed that the random copolymers possess superior charge carrier selectivity. For materials of comparable ion content, at 10 mA/cm2 the random copolymer displayed a 14% increase in coulombic efficiency (CE) corresponding to a 7% increase in energy efficiency. All quaternary ammonium materials displayed ex situ degradation in a 0.5 M V5+ + 5 M H2SO4 solution, with the rate of degradation appearing to increase with IEC. Preliminary studies reveal that the neutralizing counter-ion has a significant effect on VRB performance, proportional to changes in vanadium ion molecular diffusion.

Computer model of hydroponics nutrient solution pH control using ammonium.

PubMed

Pitts, M; Stutte, G

1999-01-01

A computer simulation of a hydroponics-based plant growth chamber using ammonium to control pH was constructed to determine the feasibility of such a system. In nitrate-based recirculating hydroponics systems, the pH will increase as plants release hydroxide ions into the nutrient solution to maintain plant charge balance. Ammonium is an attractive alternative to traditional pH controls in an ALSS, but requires careful monitoring and control to avoid overdosing the plants with ammonium. The primary advantage of using NH4+ for pH control is that it exploits the existing plant nutrient uptake charge balance mechanisms to maintain solution pH. The simulation models growth, nitrogen uptake, and pH of a l-m2 stand of wheat. Simulation results indicated that ammonium-based control of nutrient solution pH is feasible using a proportional integral controller. Use of a 1 mmol/L buffer (Ka = 1.6 x 10(-6)) in the nutrient solution is required.

Analysis of nine food additives in red wine by ion-suppression reversed-phase high-performance liquid chromatography using trifluoroacetic acid and ammonium acetate as ion-suppressors.

PubMed

Zhao, Yong-Gang; Chen, Xiao-Hong; Yao, Shan-Shan; Pan, Sheng-Dong; Li, Xiao-Ping; Jin, Mi-Cong

2012-01-01

A reversed-phase high-performance liquid chromatography (RP-HPLC) method was developed for the simultaneous determination of nine food additives, i.e., acesulfame, saccharin, caffeine, aspartame, benzoic acid, sorbic acid, stevioside, dehydroacetic acid and neotame in red wine. The effects of ion-suppressors, i.e., trifluoroacetic acid (TFA) and ammonium acetate (AmAc) on retention behavior of nine food additives in RP-HPLC separation were discussed in detail. The relationships between retention factors of solutes and volume percent of ion-suppressors in the mobile-phase systems of acetonitrile-TFA aqueous solution and acetonitrile-TFA-AmAc aqueous solution were quantitatively established, respectively. The results showed that the ion suppressors had not only an ion suppression effect, but also an organic modification effect on the acidic analytes. The baseline separation of nine food additives was completed by a gradient elution with acetonitrile-TFA(0.01%, v/v)-AmAc(2.5 mmol L(-1)) aqueous solution as the mobile phase. The recoveries were between 80.2 - 99.5% for all analytes with RSDs in the range of 1.5 - 8.9%. The linearities were in the range of 0.2 - 100.0 mg L(-1) with determination coefficients (r(2)) higher than 0.9991 for all analytes. The limits of quantification (LOQs) were between 0.53 - 0.99 mg L(-1). The applicability of the proposed method to detect and quantify food additives has been demonstrated in the analysis of 30 real samples.

Globular, Sponge-like to Layer-like Morphological Transition in 1-n-Alkyl-3-methylimidazolium Octylsulfate Ionic Liquid Homologous Series.

PubMed

Kapoor, Utkarsh; Shah, Jindal K

2018-01-11

Segregation of polar and nonpolar domains in ionic liquids for which either the cation or anion is responsible for inducing nonpolar domains is well understood. On the other hand, information regarding the nanoscale heterogeneities originating due to the presence of nonpolar content on both the ions is rudimentary at this point. The present contribution is aimed at addressing this question and focuses on a molecular dynamics simulation study to probe nanoscale structural and aggregation features of the 1-n-alkyl-3-methylimidazolium [C n mim] octylsulfate [C 8 SO 4 ] ionic liquid homologous series (n = 2, 4, 6, 8, 10, and 12). The objective of this work is to determine the effect of increasing alkyl chain length in the cation on nonpolar domain formation, especially when the alkyl chain lengths from both the ions participate in defining such domains. The results indicate that all the ionic liquids form nonpolar domains, morphology of which gradually changes from globular, sponge-like to layer-like structure with increase in the cationic alkyl chain length. The length of the nonpolar domains calculated from the total structure factor for [C 10 mim][C 8 SO 4 ] is considerably higher than that reported for other imidazolium-based ionic liquid containing smaller anions. The structure factor for [C 12 mim][C 8 SO 4 ] ionic liquid contains multiple intermediate peaks separating the charge alternation peak and pre-peak, which points to nonpolar domains of varying lengths, an observation that remains to be validated. Analysis of the heterogeneous order parameters and orientational correlation functions of the alkyl chains further suggests an increase in the spatial heterogeneity and long-range order along the homologous series. The origin of rich diversity of structures obtained by introducing nonpolar content on both the ions is discussed.

40 CFR 180.910 - Inert ingredients used pre- and post-harvest; exemptions from the requirement of a tolerance.

Code of Federal Regulations, 2011 CFR

2011-07-01

... formulation Surfactant α-Alkyl(C6-C15)-ω-hydroxypoly(oxyethylene)sulfate, and its ammonium, calcium, magnesium..., related adjuvants of surfactants Alkyl (C8-C18) sulfate and its ammonium, calcium, isopropylamine... stearate Surfactant Ammonium sulfate Solid diluent, carrier Ammonium thiosulfate Intensifier when used with...

Method of making alkyl esters

DOEpatents

Elliott, Brian

2010-09-14

Methods of making alkyl esters are described herein. The methods are capable of using raw, unprocessed, low-cost feedstocks and waste grease. Generally, the method involves converting a glyceride source to a fatty acid composition and esterifying the fatty acid composition to make alkyl esters. In an embodiment, a method of making alkyl esters comprises providing a glyceride source. The method further comprises converting the glyceride source to a fatty acid composition comprising free fatty acids and less than about 1% glyceride by mass. Moreover, the method comprises esterifying the fatty acid composition in the presence of a solid acid catalyst at a temperature ranging firm about 70.degree. C. to about 120.degree. C. to produce alkyl esters, such that at least 85% of the free fatty acids are converted to alkyl esters. The method also incorporates the use of packed bed reactors for glyceride conversion and/or fatty acid esterification to make alkyl esters.

Stereoconvergent Amine-Directed Alkyl–Alkyl Suzuki Reactions of Unactivated Secondary Alkyl Chlorides

PubMed Central

Lu, Zhe; Wilsily, Ashraf; Fu, Gregory C.

2011-01-01

A new family of stereoconvergent cross-couplings of unactivated secondary alkyl electrophiles has been developed, specifically, arylamine-directed alkyl–alkyl Suzuki reactions. This represents the first such investigation to be focused on the use of alkyl chlorides as substrates. Structure-enantioselectivity studies are consistent with the nitrogen, not the aromatic ring, serving as the primary site of coordination of the arylamine to the catalyst. The rate law for this asymmetric cross-coupling is compatible with transmetalation being the turnover-limiting step of the catalytic cycle. PMID:21553917

Poly(terphenylene) Anion Exchange Membranes: The Effect of Backbone Structure on Morphology and Membrane Property

DOE PAGES

Lee, Woo-Hyung; Park, Eun Joo; Han, Junyoung; ...

2017-05-05

A new design concept for ion-conducting polymers in anion exchange membranes (AEMs) fuel cells is proposed based on structural studies and conformational analysis of polymers and their effect on the properties of AEMs. Thermally, chemically, and mechanically stable terphenyl-based polymers with pendant quaternary ammonium alkyl groups were synthesized to investigate the effect of varying the arrangement of the polymer backbone and cation-tethered alkyl chains. The results demonstrate that the microstructure and morphology of these polymeric membranes significantly influence ion conductivity and fuel cell performance. Finally, the results of this study provide new insights that will guide the molecular design ofmore » polymer electrolyte materials to improve fuel cell performance.« less

Mechanism by which ammonium bicarbonate and ammonium sulfate inhibit mycotoxigenic fungi.

PubMed Central

DePasquale, D A; Montville, T J

1990-01-01

In this study we examined the mechanism by which ammonium bicarbonate inhibits mycotoxigenic fungi. Elevated extracellular pH, alone, was not responsible for the antifungal activity. Although conidia of Penicillium griseofulvum and Fusarium graminearum had internal pH (pHi) values as high as 8.0 in buffer at an external pH (pHo) of 9.5, their viability was not markedly affected. The pHi values from conidia equilibrated in glycine-NaOH-buffered treatments without ammonium bicarbonate or ammonium sulfate were similar to values obtained from buffered treatments containing the ammonium salts. Thus, inhibition did not appear to be directly related to increased pHi. Ammonium sulfate in buffered media at pH greater than or equal to 8.7 was as inhibitory as ammonium bicarbonate, but was completely ineffective at pH less than or equal to 7.8. The hypothesis that free ammonia caused the fungal inhibition was tested by using ammonium sulfate as a model for ammonium bicarbonate. Viability, expressed as log CFU/ml, and percent germination of P. griseofulvum and F. graminearum decreased dramatically as the free ammonia concentration increased. Germination rate ratios (the germination rate in buffered ammonium sulfate divided by the germination rate in buffer alone) decreased linearly as the free ammonia concentration increased, further establishing NH3 as the toxic agent. Ammonium bicarbonate inhibits fungi because the bicarbonate anion supplies the alkalinity necessary to establish an antifungal concentration of free ammonia. PMID:2082821

Alkylation of enolates: An electrophilicity perspective

NASA Astrophysics Data System (ADS)

Elango, M.; Parthasarathi, R.; Subramanian, V.; Chattaraj, P. K.

Enolates are ambient nucleophiles, and alkylation can occur either at a carbon or at an oxygen site. It is known that the ratio of C/O alkylation depends significantly on various factors, including the type of enolate, alkylating agent, site of alkylation, and solvent environment. Analysis of regioselectivity and solvent effects on alkylation of lithium enolates is investigated using various reactivity descriptors, including generalized philicity. These results point out the reliability of both global and local reactivity descriptors in providing significant information about site selectivity and chemical reactivity of lithium enolates.

Salting out of proteins using ammonium sulfate precipitation.

PubMed

Duong-Ly, Krisna C; Gabelli, Sandra B

2014-01-01

Protein solubility is affected by ions. At low ion concentrations (<0.5 M), protein solubility increases along with ionic strength. Ions in the solution shield protein molecules from the charge of other protein molecules in what is known as 'salting-in'. At a very high ionic strength, protein solubility decreases as ionic strength increases in the process known as 'salting-out'. Thus, salting out can be used to separate proteins based on their solubility in the presence of a high concentration of salt. In this protocol, ammonium sulfate will be added incrementally to an E. coli cell lysate to isolate a recombinantly over-expressed protein of 20 kDa containing no cysteine residues or tags. © 2014 Elsevier Inc. All rights reserved.

Paleosols in central Illinois as potential sources of ammonium in groundwater

USGS Publications Warehouse

Glessner, Justin J. G.; Roy, W.R.

2009-01-01

Glacially buried paleosols of pre-Holocene age were evaluated as potential sources for anomalously large concentrations of ammonium in groundwater in East Central Illinois. Ammonium has been detected at concentrations that are problematic to water treatment facilities (greater than 2.0 mg/L) in this region. Paleosols characterized for this study were of Quaternary age, specifically Robein Silt samples. Paleosol samples displayed significant capacity to both store and release ammonium through experiments measuring processes of sorption, ion exchange, and weathering. Bacteria and fungi within paleosols may significantly facilitate the leaching of ammonium into groundwater by the processes of assimilation and mineralization. Bacterial genetic material (DNA) was successfully extracted from the Robein Silt, purified, and amplified by polymerase chain reaction to produce 16S rRNA terminal restriction fragment length polymorphism (TRFLP) community analyses. The Robein Silt was found to have established diverse and viable bacterial communities. 16S rRNA TRFLP comparisons to well-known bacterial species yielded possible matches with facultative chemolithotrophs, cellulose consumers, nitrate reducers, and actinomycetes. It was concluded that the Robein Silt is both a source and reservoir for groundwater ammonium. Therefore, the occurrence of relatively large concentrations of ammonium in groundwater monitoring data may not necessarily be an indication of only anthropogenic contamination. The results of this study, however, need to be placed in a hydrological context to better understand whether paleosols can be a significant source of ammonium to drinking water supplies. ?? 2009 National Ground Water Association.

Thioimidazolium Ionic Liquids as Tunable Alkylating Agents.

PubMed

Guterman, Ryan; Miao, Han; Antonietti, Markus

2018-01-19

Alkylating ionic liquids based on the thioimidazolium structure combine the conventional properties of ionic liquids, including low melting point and nonvolatility, with the alkylating function. Alkyl transfer occurs exclusively from the S-alkyl position, thus allowing for easy derivatization of the structure without compromising specificity. We apply this feature to tune the electrophilicty of the cation to profoundly affect the reactivity of these alkylating ionic liquids, with a caffeine-derived compound possessing the highest reactivity. Anion choice was found to affect reaction rates, with iodide anions assisting in the alkylation reaction through a "shuttling" process. The ability to tune the properties of the alkylating agent using the toolbox of ionic liquid chemistry highlights the modular nature of these compounds as a platform for alkylating agent design and integration in to future systems.

Developing a Genetically Encoded, Cross-Species Biosensor for Detecting Ammonium and Regulating Biosynthesis of Cyanophycin.

PubMed

Xiao, Yi; Jiang, Wen; Zhang, Fuzhong

2017-10-20

Responding to nitrogen status is essential for all living organisms. Bacteria have evolved various complex and exquisite regulatory systems to control nitrogen metabolism. However, natural nitrogen regulatory systems, owing to their complexity, often function only in their original hosts and do not respond properly when transferred to another species. By harnessing the Lactococcus GlnRA system, we developed a genetically encoded, cross-species ammonium biosensor that displays a dynamic range up to 9-fold upon detection of ammonium ion. We demonstrated applications of this ammonium biosensor in three different species (Escherichia coli, Pseudomonas putida, and Synechocystis sp.) to detect different nitrogen sources. This ammonium sensor was further used to regulate the biosynthesis of a nitrogen-rich polymer, cyanophycin, based on ammonium concentration. Given the importance of nitrogen responses, the developed biosensor should be broadly applicable to synthetic biology and bioengineering.

40 CFR 180.910 - Inert ingredients used pre- and post-harvest; exemptions from the requirement of a tolerance.

Code of Federal Regulations, 2010 CFR

2010-07-01

... formulation Surfactant α-Alkyl(C6-C15)-ω-hydroxypoly(oxyethylene)sulfate, and its ammonium, calcium, magnesium... Alkyl (C8-C18) sulfate and its ammonium, calcium, isopropylamine, magnesium, potassium, sodium, and zinc..., 93917-76-1, 5297-93-8, 94266-36-1, 1002-89-7) Surfactant Ammonium stearate Surfactant Ammonium sulfate...

NaA zeolite derived from blast furnace slag: its application for ammonium removal.

PubMed

Guo, Hongwei; Tang, Lizhen; Yan, Bingji; Wan, Kang; Li, Peng

2017-09-01

In this paper, high value added NaA zeolite material was prepared from blast furnace (BF) slag by hydrothermal method and its adsorption behavior on the removal of ammonium ion was investigated. It was found out that the synthetic NaA cubic zeolite with smaller crystal size obtained at nSiO 2 /nAl 2 O 3 = 2 and nH 2 O/nNaOH = 20 showed better adsorption performance. The kinetics of the adsorption of ammonium ion by synthesized NaA zeolite was fitted by the pseudo-second-order kinetic model. The intra-particle diffusion modeling reveals that two mixed rate-controlling mechanisms were involved in the adsorption process. The relatively high value of activation energy of 92.3 kJ·mol -1 indicates a high impact of temperature on the adsorption rate, and the nature of ammonium adsorption is chemical reaction rather than physisorption. Based on the thermodynamics calculations, the adsorption of ammonium was found to be an endothermic, spontaneous process. The adsorption isothermal analysis showed that the Langmuir model could be well fitted and a maximum adsorption capacity of 83.3 mg·g -1 of NH 4 + was obtained. Thus, it was demonstrated that by forming low cost NaA zeolite and using it for environmental remediation, the synchronous minimization of BF slag and ammonia nitrogen contamination could be achieved.

Synthesis and DNA cleavage activity of Bis-3-chloropiperidines as alkylating agents.

PubMed

Zuravka, Ivonne; Roesmann, Rolf; Sosic, Alice; Wende, Wolfgang; Pingoud, Alfred; Gatto, Barbara; Göttlich, Richard

2014-09-01

Nitrogen mustards are an important class of bifunctional alkylating agents routinely used in chemotherapy. They react with DNA as electrophiles through the formation of highly reactive aziridinium ion intermediates. The antibiotic 593A, with potential antitumor activity, can be considered a naturally occurring piperidine mustard containing a unique 3-chloropiperidine ring. However, the total synthesis of this antibiotic proved to be rather challenging. With the aim of designing simplified analogues of this natural product, we developed an efficient bidirectional synthetic route to bis-3-chloropiperidines joined by flexible, conformationally restricted, or rigid diamine linkers. The key step involves an iodide-catalyzed double cyclization of unsaturated bis-N-chloroamines to simultaneously generate both piperidine rings. Herein we describe the synthesis and subsequent evaluation of a series of novel nitrogen-bridged bis-3-chloropiperidines, enabling the study of the impact of the linker structure on DNA alkylation properties. Our studies reveal that the synthesized compounds possess DNA alkylating abilities and induce strand cleavage, with a strong preference for guanine residues. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Determination of trace quaternary ammonium surfactants in water by combining solid-phase extraction with surface-assisted laser desorption/ionization mass spectrometry.

PubMed

Chen, Y C; Sun, M C

2001-01-01

This study demonstrates the feasibility of combining solid-phase extraction (SPE) with surface-assisted laser desorption/ionization (SALDI) mass spectrometry to determine trace quaternary ammonium surfactants in water. The trace surfactants in water were directly concentrated on the surface of activated carbon sorbent in SPE. The activated carbon sorbent was then mixed with the SALDI liquid for SALDI analysis. No SPE elution procedure was necessary. Experimental results indicate that the surfactants with longer chain alkyl groups exhibit higher sensitivities than those with shorter chain alkyl groups in SPE-SALDI analysis. The detection limit for hexadecyltrimethylammonium bromide is around 10 ppt in SPE-SALDI analysis by sampling 100 mL of aqueous solution, while that of tetradecyltrimethylammonium bromide is about 100 ppt. The detection limit for decyltrimethylammonium bromide and dodecyltrimethylammonium bromide is in the low-ppb range. Copyright 2001 John Wiley & Sons, Ltd.

Enhancing biodegradation of C16-alkyl quaternary ammonium compounds using an oxygen-based membrane biofilm reactor.

PubMed

Lai, YenJung Sean; Ontiveros-Valencia, Aura; Ilhan, Zehra Esra; Zhou, Yun; Miranda, Evelyn; Maldonado, Juan; Krajmalnik-Brown, Rosa; Rittmann, Bruce E

2017-10-15

Quaternary ammonium compounds (QACs) (e.g., hexadecyltrimethyl-ammonium bromide, CTAB) are emerging contaminants with widespread use as surfactants and disinfectants. Because the initial step of QAC biodegradation is mono-oxygenation, QAC degraders require O 2 , but normal aeration leads to serious foaming. Here, we developed and tested an oxygen-based membrane biofilm reactor (O 2 -MBfR) that delivers O 2 by diffusion through the walls of hollow-membranes to a biofilm accumulating on the outer surface of membranes. The O 2 -MBfR sustained QAC biodegradation even with high and toxic QAC input concentrations, up to 400 mg/L CTAB. Bubbleless O 2 transfer completely eliminated foaming, and biofilm accumulation helped the QAC biodegraders resist toxicity. Pseudomonas, Achromobacter, Stenotrophomonas, and members of the Xanthomonadaceae family were dominant in the biofilm communities degrading CTAB, and their proportions depended on the O 2 -delivery capacity of the membranes. Bacteria capable of biodegrading QACs often harbor antibiotic resistance genes (ARGs) that help them avoid QAC toxicity. Gene copies of ARGs were detected in biofilms and liquid, but the levels of ARGs were 5- to 35-fold lower in the liquid than in the biofilm. In summary, the O 2 -MBfR achieved aerobic biodegradation of CTAB with neither foaming nor toxicity, and it also minimized the spread of ARGs. Copyright © 2017 Elsevier Ltd. All rights reserved.

Low-EC-Content Electrolytes for Low-Temperature Li-Ion Cells

NASA Technical Reports Server (NTRS)

Smart, Marshall; Bugga, Ratnakumar; Surampudi, Subbarao

2003-01-01

Electrolytes comprising LiPF6 dissolved at a concentration of 1.0 M in three different mixtures of alkyl carbonates have been found well suited for use in rechargeable lithium-ion electrochemical cells at low temperatures. These and other electrolytes have been investigated in continuing research directed toward extending the lower limit of practical operating temperatures of Li-ion cells down to -60 C. This research at earlier stages was reported in numerous previous NASA Tech Briefs articles, the three most recent being "Ethyl Methyl Carbonate as a Cosolvent for Lithium-Ion Cells" (NPO-20605), Vol. 25, Low-EC-Content Electrolytes for Low-Temperature Li-Ion Cells No. 6 (June 2001), page 53; "Alkyl Pyrocarbonate Electrolyte Additives for Li-Ion Cells" (NPO-20775), Vol. 26, No. 5 (May 2002), page 37; and "Fluorinated Alkyl Carbonates as Cosolvents in Li-Ion Cells (NPO-21076), Vol. 26, No. 5 (May 2002), page 38. The present solvent mixtures, in terms of volume proportions of their ingredients, are 1 ethylene carbonate (EC) + 1 diethyl carbonate (DEC) + 1 dimethyl carbonate (DMC) + 3 ethyl methyl carbonate (EMC); 3EC + 3DMC + 14EMC; and 1EC + 1DEC + 1DMC + 4EMC. Relative to similar mixtures reported previously, the present mixtures, which contain smaller proportions of EC, have been found to afford better performance in experimental Li-ion cells at temperatures < -20 C.

Selective removal of cesium by ammonium molybdophosphate - polyacrylonitrile bead and membrane.

PubMed

Ding, Dahu; Zhang, Zhenya; Chen, Rongzhi; Cai, Tianming

2017-02-15

The selective removal of radionuclides with extremely low concentrations from environmental medium remains a big challenge. Ammonium molybdophosphate possess considerable selectivity towards cesium ion (Cs + ) due to the specific ion exchange between Cs + and NH 4 + . Ammonium molybdophosphate - polyacrylonitrile (AMP-PAN) membrane was successfully prepared for the first time in this study. Efficient removal of Cs + (95.7%, 94.1% and 91.3% of 1mgL -1 ) from solutions with high ionic strength (400mgL -1 of Na + , Ca 2+ or K + ) was achieved by AMP-PAN composite. Multilayer chemical adsorption process was testified through kinetic and isotherm studies. The estimated maximum adsorption capacities even reached 138.9±21.3mgg -1 . Specifically, the liquid film diffusion was identified as the rate-limiting step throughout the removal process. Finally, AMP-PAN membrane could eliminate Cs + from water effectively through the filtration adsorption process. Copyright © 2016 Elsevier B.V. All rights reserved.

Ammonium fluoride as a mobile phase additive in aqueous normal phase chromatography.

PubMed

Pesek, Joseph J; Matyska, Maria T

2015-07-03

The use of ammonium fluoride as a mobile phase additive in aqueous normal phase chromatography with silica hydride-based stationary phases and mass spectrometry detection is evaluated. Retention times, peak shape, efficiency and peak intensity are compared to the more standard additives formic acid and ammonium formate. The test solutes were NAD, 3-hydroxyglutaric acid, α-ketoglutaric acid, p-aminohippuric acid, AMP, ATP, aconitic acid, threonine, N-acetyl carnitine, and 3-methyladipic acid. The column parameters are assessed in both the positive and negative ion detection modes. Ammonium fluoride is potentially an aggressive mobile phase additive that could have detrimental effects on column lifetime. Column reproducibility is measured and the effects of switching between different additives are also tested. Copyright © 2015 Elsevier B.V. All rights reserved.

Ion sensing by charge transfer absorption variations of benzocrown-bipyridinium conjugates with an alkyl chain.

PubMed

Kuwabara, Tetsuo; Satake, Ryota; Guo, Haocheng

2015-01-01

Two benzocrown ether-bipyridinium conjugates, 1 and 2, each having a different length of alkyl chains with butyl and dodecyl groups, respectively, have been synthesized for the purpose of developing a new guest-responsive color-change chemosensor. Both 1 and 2 showed yellow colors with broad absorption bands around 400 nm in acetonitrile. These are associated with the intramolecular charge transfer (CT) absorption, in which the benzocrown ether and bipyridinium units act as the donor and acceptor, respectively. Upon addition of the guest; such as Na(+), they faded in color due to the blue shift in their intramolecular charge transfer absorption bands. These are associated with the formation of 1:1 host-guest inclusion complex. Analogues, 3 and 4, both being similar in structure to 1 and 2 with non-crown ether unit, also showed intramolecular CT absorptions around 400 nm, but did not change their absorption spectra upon addition of the guest because of the lack of guest-binding abilities. The guest-induced color change of 1 and 2 can be used for alkali and alkaline metal ion sensing. Both 1 and 2 could detect divalent cations such as Mg(2+) and Ca(2+) rather than univalent ones, Li(+), Na(+), K(+), Rb(+), and Cs(+). Although a marked difference between 1 and 2 was not observed in their guest sensing abilities, the remarkable recognition of 1 and 2 for Mg(2+) and Ca(2+) was found compared with that of 5, which has benzyl unit instead of alkyl chains of 1 and 2. The sensitivity values of 1 and 2 were roughly proportional to their binding constants, as shown by the binding constants with Li(+), Na(+), Mg(2+), and Ca(2+) with the values of 910, 260, 820, and 2300 M(-1) for 1 and 930, 290, 1270, and 2790 M(-1) for 2, while the binding constants of 5 were estimated to be 930, 440, 210, and 1200 M(-1) for Li(+), Na(+), Mg(2+), and Ca(2+), respectively. The limit concentration of detection of 2 for Ca(2+) was estimated to be 0.016 mM, which was the smallest value in this

Transition-Metal-Catalyzed C-H Alkylation Using Alkenes.

PubMed

Dong, Zhe; Ren, Zhi; Thompson, Samuel J; Xu, Yan; Dong, Guangbin

2017-07-12

Alkylation reactions represent an important organic transformation to form C-C bonds. In addition to conventional approaches with alkyl halides or sulfonates as alkylating agents, the use of unactivated olefins for alkylations has become attractive from both cost and sustainability viewpoints. This Review summarizes transition-metal-catalyzed alkylations of various carbon-hydrogen bonds (addition of C-H bonds across olefins) using regular olefins or 1,3-dienes up to May 2016. According to the mode of activation, the Review is divided into two sections: alkylation via C-H activation and alkylation via olefin activation.

Photoinduced, copper-catalyzed alkylation of amides with unactivated secondary alkyl halides at room temperature.

PubMed

Do, Hien-Quang; Bachman, Shoshana; Bissember, Alex C; Peters, Jonas C; Fu, Gregory C

2014-02-05

The development of a mild and general method for the alkylation of amides with relatively unreactive alkyl halides (i.e., poor substrates for SN2 reactions) is an ongoing challenge in organic synthesis. We describe herein a versatile transition-metal-catalyzed approach: in particular, a photoinduced, copper-catalyzed monoalkylation of primary amides. A broad array of alkyl and aryl amides (as well as a lactam and a 2-oxazolidinone) couple with unactivated secondary (and hindered primary) alkyl bromides and iodides using a single set of comparatively simple and mild conditions: inexpensive CuI as the catalyst, no separate added ligand, and C-N bond formation at room temperature. The method is compatible with a variety of functional groups, such as an olefin, a carbamate, a thiophene, and a pyridine, and it has been applied to the synthesis of an opioid receptor antagonist. A range of mechanistic observations, including reactivity and stereochemical studies, are consistent with a coupling pathway that includes photoexcitation of a copper-amidate complex, followed by electron transfer to form an alkyl radical.

Polyimides with pendant alkyl groups

NASA Technical Reports Server (NTRS)

Jensen, B. J.; Young, P. R.

1982-01-01

The effect on selected polyimide properties when pendant alkyl groups were attached to the polymer backbone was investigated. A series of polymers were prepared using benzophenone tetracarboxylic acid dianhydride (BTDA) and seven different p-alkyl-m,p'-diaminobenzophenone monomers. The alkyl groups varied in length from C(1) (methyl) to C(9) (nonyl). The polyimide prepared from BTDA and m,p'-diaminobenzophenone was included as a control. All polymers were characterized by various chromatographic, spectroscopic, thermal, and mechanical techniques. Increasing the length of the pendant alkyl group resulted in a systematic decrease in glass transition temperature (Tg) for vacuum cured films. A 70 C decrease in Tg to 193 C was observed for the nonyl polymer compared to the Tg for the control. A corresponding systematic increase in Tg indicative of crosslinking, was observed for air cured films. Thermogravimetric analysis revealed a slight sacrifice in thermal stability with increasing alkyl length. No improvement in film toughness was observed.

Kagomé lattices as cathode: Effect of particle size and fluoride substitution on electrochemical lithium insertion in sodium- and ammonium Jarosites

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sandineni, Prashanth; Yaghoobnejad Asl, Hooman; Choudhury, Amitava, E-mail: choudhurya@mst.edu

Highly crystalline sodium and ammonium Jarosites, NaFe{sub 3}(SO{sub 4}){sub 2}(OH){sub 6} and NH{sub 4}Fe{sub 3}(SO{sub 4}){sub 2}(OH){sub 6}, have been synthesized employing hydrothermal synthesis routes. The structures consist of anionic layers of vertex-sharing FeO{sub 6} octahedra and SO{sub 4} tetrahedral units with interlayer space occupied by Na and ammonium ions, respectively. The corner-sharing FeO{sub 6} octahedral units form six and three rings similar to hexagonal tungsten bronze sheets also known as kagomé lattice. These sodium and ammonium Jarosites are thermally stable up to 400 °C and undergo facile electrochemical lithium insertion through the reduction of Fe{sup 3+} to Fe{sup 2+}.more » Galvanostatic charge–discharge indicates that up to 2.25 and 2 lithium ions per formula unit can be inserted at an average voltage of 2.49 and 2.26 V to the sodium and the ammonium Jarosites, respectively, under slow discharge rate of C/50. The cycle-life and experimental achievable capacity show strong dependence on particle sizes and synthesis conditions. A small amount of fluoride substitution improves both achievable capacity and average voltage. - Graphical abstract: Discharge capacity of jarosite phases as a function of particle size and fluoride substitution. - Highlights: • Synthesis of natro- and ammonium Jarosites. • Jarosites as cathodes for lithium ion batteries. • Li-ion electrochemistry of Jarosites. • Mössbauer spectroscopy of Jarosites.« less

Molecular design of sequence specific DNA alkylating agents.

PubMed

Minoshima, Masafumi; Bando, Toshikazu; Shinohara, Ken-ichi; Sugiyama, Hiroshi

2009-01-01

Sequence-specific DNA alkylating agents have great interest for novel approach to cancer chemotherapy. We designed the conjugates between pyrrole (Py)-imidazole (Im) polyamides and DNA alkylating chlorambucil moiety possessing at different positions. The sequence-specific DNA alkylation by conjugates was investigated by using high-resolution denaturing polyacrylamide gel electrophoresis (PAGE). The results showed that polyamide chlorambucil conjugates alkylate DNA at flanking adenines in recognition sequences of Py-Im polyamides, however, the reactivities and alkylation sites were influenced by the positions of conjugation. In addition, we synthesized conjugate between Py-Im polyamide and another alkylating agent, 1-(chloromethyl)-5-hydroxy-1,2-dihydro-3H-benz[e]indole (seco-CBI). DNA alkylation reactivies by both alkylating polyamides were almost comparable. In contrast, cytotoxicities against cell lines differed greatly. These comparative studies would promote development of appropriate sequence-specific DNA alkylating polyamides against specific cancer cells.

Mass spectral analysis of long chain alkyl aromatic compounds synthesized from alpha-olefin alkylation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cheng, M.T.; Hudson, J.D.

1994-12-31

Long chain alkyl aromatic compounds are important petrochemicals with many applications. They are generally synthesized by alkylating the corresponding aromatic nucleus. In this report, the authors will describe the mass spectral fragmentation of alkylphenols and alkylsalicylates.

The effect of varying linker length on ion-transport properties in polymeric ionic liquids

NASA Astrophysics Data System (ADS)

Keith, Jordan; Mogurampelly, Santosh; Wheatle, Bill; Ganesan, Venkat

We report results of atomistic molecular dynamics simulations on polymerized 1-butyl-3-(n-alkyl)imidazolium ionic liquids with PF6- counterions. Consistent with experimental observations, we observe that the mobility of the PF6- ions increases with increasing n-alkyl linker length. Analysis of our results suggests that the motion of PF6- ions is driven by intermolecular ion hopping between chains, which in turn is influenced by ion-pair coordination numbers and intermolecular ionic separation distances. With increasing linker length, we observe 1) the anions coordinating less closely with cations and 2) intermolecular hopping distances decreasing.

40 CFR 721.9892 - Alkylated urea.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Alkylated urea. 721.9892 Section 721... Alkylated urea. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as an alkylated urea (PMN P-93-1649) is subject to reporting under this...

Ammonium iron(III) phosphate(V) fluoride, (NH4)0.5[(NH4)0.375K0.125]FePO4F, with ammonium partially substituted by potassium

PubMed Central

Wang, Lei; Zhou, Yan; Huang, Ya-Xi; Mi, Jin-Xiao

2009-01-01

The title compound, ammonium potassium iron(III) phosphate fluoride, (NH4)0.875K0.125FePO4F, is built from zigzag chains ∞ 1{[FeO4F2]7−}, with Fe3+ in a distorted octahedral coordination, extending along both the [011] and [01] directions. These chains are made up of alternating trans-[FeO4F2] and cis-[FeO4F2] octa­hedra via shared F-atom corners, and are linked by PO4 tetra­hedra, resulting in an open-framework structure with channels along the [010] and [100] directions. There are two crystallographically independent ammonium sites: one in the [010] channels and the other, partially substituted by K+ ions, in the [100] channels. The ammonium in the [010] channels is fixed to the framework via eight hydrogen bonds (six N—H⋯O and two N—H⋯F). PMID:21581466

Influence of ammonium salts on the lipase/esterase activity assay using p-nitrophenyl esters as substrates.

PubMed

De Yan, Hong; Zhang, Yin Jun; Liu, Hong Cai; Zheng, Jian Yong; Wang, Zhao

2013-01-01

p-Nitrophenyl esters with a short-chain carboxylic group, such as p-nitrophenyl acetate (p-NPA) and p-nitrophenyl butyrate (p-NPB), could be effectively hydrolyzed by ammonium salts. p-Nitrophenyl esters were usually used as substrates to assay the lipase/esterase activity. Ammonium sulfate precipitation was often used to purify proteins, and some ammonium salts were usually used as nitrogen sources or inorganic salts for the lipase/esterase production. To study the effect of ammonium salts on the assay of the lipase/esterase activity, the contributing factors of hydrolysis of p-NPA/p-NPB catalyzed by ammonium salts were investigated. The lipase activities were compared in the presence and absence of ammonium sulfate. The hydrolysis reaction could be catalyzed under neutral and alkaline circumstances. The hydrolysis rate increased with the increase in the reaction temperature or the concentration of ammonium ion. When p-NPA was employed as the substrate for the analysis of the lipase/esterase activity, the effect of ammonium sulfate on the analysis could be neutralized by setting a control when the concentration of ammonium sulfate was less than 40% saturation. However, when the concentration of ammonium sulfate increased from 40% to 100% saturation, the enzyme activities decreased about 13-40%, which could not be ignored for accurate analysis of the enzyme activity. © 2013 International Union of Biochemistry and Molecular Biology, Inc.

Stereocontrolled Alkylative Construction of Quaternary Carbon Centers

PubMed Central

Kummer, David A.; Chain, William J.; Morales, Marvin R.; Quiroga, Olga; Myers, Andrew G.

2009-01-01

Protocols for the stereodefined formation of α,α-disubstituted enolates of pseudoephedrine amides are presented followed by the implementation of these in diastereoselective alkylation reactions. Direct alkylation of α,α-disubstituted pseudoephedrine amide substrates is demonstrated to be both efficient and diastereoselective across a range of substrates, as exemplified by alkylation of the diastereomeric pseudoephedrine α-methylbutyramides, where both substrates are found to undergo stereospecific replacement of the α-C-H bond with α-C-alkyl, with retention of stereochemistry. This is shown to arise by sequential stereospecific enolization and alkylation reactions, with the alkyl halide attacking a common π-face of the E- and Z-enolates, proposed to be that opposite the pseudoephedrine alkoxide side-chain. Pseudoephedrine α-phenylbutyramides are found to undergo highly stereoselective but not stereospecific α-alkylation reactions, which evidence suggests is due to facile enolate isomerization. Also, we show that α, α-disubstituted pseudoephedrine amide enolates can be generated in a highly stereocontrolled fashion by conjugate addition of an alkyllithium reagent to the s-cis-conformer of an α-alkyl-α,β-unsaturated pseudoephedrine amide, providing α,α-disubstituted enolate substrates that undergo alkylation in the same sense as those formed by direct deprotonation. Methods are presented to transform the α-quaternary pseudoephedrine amide products into optically active carboxylic acids, ketones, primary alcohols, and aldehydes. PMID:18788739

70. INTERIOR VIEW OF AMMONIUM NITRATE HOUSE, LOOKING AT AMMONIUM ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

70. INTERIOR VIEW OF AMMONIUM NITRATE HOUSE, LOOKING AT AMMONIUM NITRATE IN STORAGE. APRIL 18, 1919. - United States Nitrate Plant No. 2, Reservation Road, Muscle Shoals, Muscle Shoals, Colbert County, AL

Using Iron-Manganese Co-Oxide Filter Film to Remove Ammonium from Surface Water

PubMed Central

Zhang, Ruifeng; Huang, Tinglin; Wen, Gang; Chen, Yongpan; Cao, Xin; Zhang, Beibei

2017-01-01

An iron-manganese co-oxide filter film (MeOx) has been proven to be a good catalyst for the chemical catalytic oxidation of ammonium in groundwater. Compared with groundwater, surface water is generally used more widely and has characteristics that make ammonium removal more difficult. In this study, MeOx was used to remove ammonium from surface water. It indicated that the average ammonium removal efficiency of MeOx was greater than 90%, even though the water quality changed dramatically and the water temperature was reduced to about 6–8 °C. Then, through inactivating microorganisms, it showed that the removal capability of MeOx included both biological (accounted for about 41.05%) and chemical catalytic oxidation and chemical catalytic oxidation (accounted for about 58.95%). The investigation of the characterizations suggested that MeOx was formed by abiotic ways and the main elements on the surface of MeOx were distributed homogenously. The analysis of the catalytic oxidation process indicated that ammonia nitrogen may interact with MeOx as both ammonia molecules and ammonium ions and the active species of O2 were possibly •O and O2−. PMID:28753939

Using Iron-Manganese Co-Oxide Filter Film to Remove Ammonium from Surface Water.

PubMed

Zhang, Ruifeng; Huang, Tinglin; Wen, Gang; Chen, Yongpan; Cao, Xin; Zhang, Beibei

2017-07-19

An iron-manganese co-oxide filter film (MeO x ) has been proven to be a good catalyst for the chemical catalytic oxidation of ammonium in groundwater. Compared with groundwater, surface water is generally used more widely and has characteristics that make ammonium removal more difficult. In this study, MeO x was used to remove ammonium from surface water. It indicated that the average ammonium removal efficiency of MeO x was greater than 90%, even though the water quality changed dramatically and the water temperature was reduced to about 6-8 °C. Then, through inactivating microorganisms, it showed that the removal capability of MeO x included both biological (accounted for about 41.05%) and chemical catalytic oxidation and chemical catalytic oxidation (accounted for about 58.95%). The investigation of the characterizations suggested that MeO x was formed by abiotic ways and the main elements on the surface of MeO x were distributed homogenously. The analysis of the catalytic oxidation process indicated that ammonia nitrogen may interact with MeO x as both ammonia molecules and ammonium ions and the active species of O₂ were possibly • O and O₂ - .

On the kinetics of organic pollutant degradation with Co2+/peroxymonosulfate process: When ammonium meets chloride.

PubMed

Huang, Ying; Yang, Fei; Ai, Luoyan; Feng, Min; Wang, Chi; Wang, Zhaohui; Liu, Jianshe

2017-07-01

A large amount of chloride and ammonium ions were produced and released from industrial processes with non-biodegradable organic pollutants to affect efficiencies of advanced oxidation processes (AOPs). Here, the influences of chloride and ammonium ions on Co/peroxymonosulfate (Co/PMS) reaction system, a widely used AOPs to produce sulfate radicals, were investigated by examining the degradation efficiency of an azo dye (Acid Orange 7, AO7). The experimental results showed that a significant decrease in the degradation rate of AO7 was observed in the presence of NH 4 + , while a dual effect of chloride on AO7 bleaching appeared. The presence of NH 4 Cl was unfavorable for AO7 degradation at low concentration (<20 mM), whereas further addition of NH 4 Cl (>20 mM) apparently accelerated AO7 discoloration rate. The apparent effects of the two co-existing inorganic ions were determined by roles of the dominating ions at varied molar ratio of [NH 4 + ]/[Cl - ]. The present study may have technical implications for the treatment of industrial wastewater containing diverse ions in practice. Copyright © 2017 Elsevier Ltd. All rights reserved.

49 CFR 176.410 - Division 1.5 materials, ammonium nitrate and ammonium nitrate mixtures.

Code of Federal Regulations, 2010 CFR

2010-10-01

... (Oxidizers and Organic Peroxides), and Division 1.5 Materials § 176.410 Division 1.5 materials, ammonium...) Ammonium nitrate, Division 5.1 (oxidizer), UN1942. (3) Ammonium nitrate fertilizer, Division 5.1 (oxidizer), UN 2067. (b) This section does not apply to Ammonium nitrate fertilizer, Class 9, UN 2071 or to any...

Photoinduced, Copper-Catalyzed Carbon-Carbon Bond Formation with Alkyl Electrophiles: Cyanation of Unactivated Secondary Alkyl Chlorides at Room Temperature.

PubMed

Ratani, Tanvi S; Bachman, Shoshana; Fu, Gregory C; Peters, Jonas C

2015-11-04

We have recently reported that, in the presence of light and a copper catalyst, nitrogen nucleophiles such as carbazoles and primary amides undergo C-N coupling with alkyl halides under mild conditions. In the present study, we establish that photoinduced, copper-catalyzed alkylation can also be applied to C-C bond formation, specifically, that the cyanation of unactivated secondary alkyl chlorides can be achieved at room temperature to afford nitriles, an important class of target molecules. Thus, in the presence of an inexpensive copper catalyst (CuI; no ligand coadditive) and a readily available light source (UVC compact fluorescent light bulb), a wide array of alkyl halides undergo cyanation in good yield. Our initial mechanistic studies are consistent with the hypothesis that an excited state of [Cu(CN)2](-) may play a role, via single electron transfer, in this process. This investigation provides a rare example of a transition metal-catalyzed cyanation of an alkyl halide, as well as the first illustrations of photoinduced, copper-catalyzed alkylation with either a carbon nucleophile or a secondary alkyl chloride.

Glyoxal in aqueous ammonium sulfate solutions: products, kinetics and hydration effects.

PubMed

Yu, Ge; Bayer, Amanda R; Galloway, Melissa M; Korshavn, Kyle J; Fry, Charles G; Keutsch, Frank N

2011-08-01

Reactions and interactions between glyoxal and salts in aqueous solution were studied. Glyoxal was found to react with ammonium to form imidazole, imidazole-2-carboxaldehyde, formic acid, N-glyoxal substituted imidazole, and minor products at very low concentrations. Overall reaction orders and rates for each major product were measured. Sulfate ions have a strong and specific interaction with glyoxal in aqueous solution, which shifts the hydration equilibria of glyoxal from the unhydrated carbonyl form to the hydrated form. This ion-specific effect contributes to the observed enhancement of the effective Henry's law coefficient for glyoxal in sulfate-containing solutions. The results of UV-vis absorption and NMR spectroscopy studies of solutions of glyoxal with ammonium, methylamine, and dimethylamine salts reveal that light absorbing compounds require the formation of nitrogen containing molecules. These findings have implications on the role of glyoxal in the atmosphere, both in models of the contribution of glyoxal to form secondary organic aerosol (SOA), the role of nitrogen containing species for aerosol optical properties and in predictions of the behavior of other carbonyls or dicarbonyls in the atmosphere.

Method of uranium reclamation from aqueous systems by reactive ion exchange. [US DOE patent application; anion exchange resin of copolymerized divinyl-benzene and styrene having quarternary ammonium groups and bicarbonate ligands

DOEpatents

Maya, L.

1981-11-05

A reactive ion exchange method for separation and recovery of values of uranium, neptunium, plutonium, or americium from substantially neutral aqueous systems of said metals comprises contacting said system with an effective amount of a basic anion exchange resin of copolymerized divinyl-benzene and styrene having quarternary ammonium groups and bicarbonate ligands to achieve nearly 100% sorption of said actinyl ion onto said resin and an aqueous system practically free of said actinyl ions. The method is operational over an extensive range of concentrations from about 10/sup -6/ M to 1.0 M actinyl ion and a pH range of about 4 to 7. The method has particulr application to treatment of waste streams from Purex-type nuclear fuel reprocessing facilities and hydrometallurgical processes involving U, Np, P, or Am.

[Achievement of Sulfate-Reducing Anaerobic Ammonium Oxidation Reactor Started with Nitrate-Reducting Anaerobic Ammonium Oxidation].

PubMed

Liu, Zheng-chuan; Yuan, Lin-jiang; Zhou, Guo-biao; Li, Jing

2015-09-01

The transformation of nitrite-reducing anaerobic ammonium oxidation to sulfate-reducing anaerobic ammonium oxidation in an UASB was performed and the changes in microbial community were studied. The result showed that the sulfate reducing anaerobic ammonium oxidation process was successfully accomplished after 177 days' operation. The removal rate of ammonium nitrogen and sulfate were up to 58. 9% and 15. 7%, the removing load of ammonium nitrogen and sulfate were 74. 3 mg.(L.d)-1 and 77. 5 mg.(L.d)-1 while concentration of ammonium nitrogen and sulfate of influent were 130 mg.(L.d)-1 and 500 mg.(L.d)-1, respectively. The lost nitrogen and sulphur was around 2 in molar ratio. The pH value of the effluent was lower than that of the influent. Instead of Candidatus brocadia in nitrite reducing anaerobic ammonium oxidation granular sludge, Bacillus benzoevorans became the dominant species in sulfate reducing anaerobic ammonium oxidation sludge. The dominant bacterium in the two kinds of anaerobic ammonium oxidation process is different. Our results imply that the two anaerobic ammonium oxidation processes are carried out by different kind of bacterium.

Alkyl chain interaction at the surface of room temperature ionic liquids: systematic variation of alkyl chain length (R = C(1)-C(4), C(8)) in both cation and anion of [RMIM][R-OSO(3)] by sum frequency generation and surface tension.

PubMed

Santos, Cherry S; Baldelli, Steven

2009-01-29

The gas-liquid interface of halide-free 1,3-dialkylimidazolium alkyl sulfates [RMIM][R-OSO(3)] with R chain length from C(1)-C(4) and C(8) has been studied systematically using the surface-specific sum frequency generation (SFG) vibrational spectroscopy and surface tension measurements. From the SFG spectra, vibrational modes from the methyl group of both cation and anion are observed for all ionic liquid samples considered in the present study. These results suggest the presence of both ions at the gas-liquid interface, which is further supported by surface tension measurements. Surface tension data show a decreasing trend as the alkyl chain in the imidazolium cation is varied from methyl to butyl chain, with a specific anion. A similar trend is observed when the alkyl chain of the anion is modified and the cation is fixed.

Optical constants of ammonium sulfate in the infrared. [stratospheric aerosol refractive and absorption indices

NASA Technical Reports Server (NTRS)

Downing, H. D.; Pinkley, L. W.; Sethna, P. P.; Williams, D.

1977-01-01

The infrared spectral reflectance at near normal incidence has been measured for 3.2 M, 2.4 M, and 1.6 M solutions of ammonium sulfate, an aerosol abundant in the stratosphere and also present in the troposphere. Kramers-Kronig analysis was used to determine values of the refractive and absorption indices from the measured spectral reflectance. A synthetic spectrum of crystalline ammonium sulfate was obtained by extrapolation of the absorption index obtained for the solution to the absorber number densities of the NH4 and SO4 ions characteristic of the crystal.

Ammonium hydroxide poisoning

MedlinePlus

Ammonium hydroxide is a colorless liquid chemical solution. It is in a class of substances called caustics. Ammonium hydroxide forms when ammonia dissolves in water. This article discusses poisoning from ...

Ruthenium-catalyzed alkylation of indoles with tertiary amines by oxidation of a sp3 C-H bond and Lewis acid catalysis.

PubMed

Wang, Ming-Zhong; Zhou, Cong-Ying; Wong, Man-Kin; Che, Chi-Ming

2010-05-17

Ruthenium porphyrins (particularly [Ru(2,6-Cl(2)tpp)CO]; tpp=tetraphenylporphinato) and RuCl(3) can act as oxidation and/or Lewis acid catalysts for direct C-3 alkylation of indoles, giving the desired products in high yields (up to 82% based on 60-95% substrate conversions). These ruthenium compounds catalyze oxidative coupling reactions of a wide variety of anilines and indoles bearing electron-withdrawing or electron-donating substituents with high regioselectivity when using tBuOOH as an oxidant, resulting in the alkylation of N-arylindoles to 3-{[(N-aryl-N-alkyl)amino]methyl}indoles (yield: up to 82%, conversion: up to 95%) and the alkylation of N-alkyl or N-H indoles to 3-[p-(dialkylamino)benzyl]indoles (yield: up to 73%, conversion: up to 92%). A tentative reaction mechanism involving two pathways is proposed: an iminium ion intermediate may be generated by oxidation of an sp(3) C-H bond of the alkylated aniline by an oxoruthenium species; this iminium ion could then either be trapped by an N-arylindole (pathway A) or converted to formaldehyde, allowing a subsequent three-component coupling reaction of the in situ generated formaldehyde with an N-alkylindole and an aniline in the presence of a Lewis acid catalyst (pathway B). The results of deuterium-labeling experiments are consistent with the alkylation of N-alkylindoles via pathway B. The relative reaction rates of [Ru(2,6-Cl(2)tpp)CO]-catalyzed oxidative coupling reactions of 4-X-substituted N,N-dimethylanilines with N-phenylindole (using tBuOOH as oxidant), determined through competition experiments, correlate linearly with the substituent constants sigma (R(2)=0.989), giving a rho value of -1.09. This rho value and the magnitudes of the intra- and intermolecular deuterium isotope effects (k(H)/k(D)) suggest that electron transfer most likely occurs during the initial stage of the oxidation of 4-X-substituted N,N-dimethylanilines. Ruthenium-catalyzed three-component reaction of N-alkyl/N-H indoles

Separation of aromatic carboxylic acids using quaternary ammonium salts on reversed-phase HPLC. 1. Separation behavior of aromatic carboxylic acids

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kawamura, K.; Okuwaki, A.; Verheyen, T.

In order to develop separation processes and analytical methods for aromatic carboxylic acids for the coal oxidation products, the separation behavior of aromatic carboxylic acids on a reversed-phase HPLC using eluent containing quaternary ammonium salt has been investigated. The retention mechanism of aromatic carboxylic acids was discussed on the basis of both ion-pair partition model and ion-exchange model. The retention behavior of aromatic carboxylic acids possessing one (or two) carboxylic acid group(s) followed the ion-pair partition model, where linear free energy relationship was observed between the capacity factor and the extraction equilibrium constants of benzoic acid and naphthalene carboxylic acid.more » Besides, the retention behavior followed ion-exchange model with increasing the number of carboxylic acids, where the capacity factor of benzene polycarboxylic acids is proportional to the association constants between aromatic acids and quaternary ammonium ions calculated on the basis of an electrostatic interaction model.« less

Palladium-Catalyzed Borylation of Primary Alkyl Bromides

PubMed Central

Joshi-Pangu, Amruta; Ma, Xinghua; Diane, Mohamed; Iqbal, Sidra; Kribs, Robert J.; Huang, Richard; Wang, Chao-Yuan

2012-01-01

A mild Pd-catalyzed process for the borylation of alkyl bromides has been developed using bis(pinacolato)diboron as a boron source. This process accommodates the use of a wide range of functional groups on the alkyl bromide substrate. Primary bromides react with complete selectivity in the presence of a secondary bromide. The generality of this approach is demonstrated by its extension to the use of alkyl iodides and alkyl tosylates, as well as borylation reactions employing bis(neopentyl glycolato)diboron as the boron source. PMID:22774861

Structural and Mechanistic Analysis of the Choline Sulfatase from Sinorhizobium melliloti: A Class I Sulfatase Specific for an Alkyl Sulfate Ester.

PubMed

van Loo, Bert; Schober, Markus; Valkov, Eugene; Heberlein, Magdalena; Bornberg-Bauer, Erich; Faber, Kurt; Hyvönen, Marko; Hollfelder, Florian

2018-03-30

Hydrolysis of organic sulfate esters proceeds by two distinct mechanisms, water attacking at either sulfur (S-O bond cleavage) or carbon (C-O bond cleavage). In primary and secondary alkyl sulfates, attack at carbon is favored, whereas in aromatic sulfates and sulfated sugars, attack at sulfur is preferred. This mechanistic distinction is mirrored in the classification of enzymes that catalyze sulfate ester hydrolysis: arylsulfatases (ASs) catalyze S-O cleavage in sulfate sugars and arylsulfates, and alkyl sulfatases break the C-O bond of alkyl sulfates. Sinorhizobium meliloti choline sulfatase (SmCS) efficiently catalyzes the hydrolysis of alkyl sulfate choline-O-sulfate (k cat /K M =4.8×10 3 s -1 M -1 ) as well as arylsulfate 4-nitrophenyl sulfate (k cat /K M =12s -1 M -1 ). Its 2.8-Å resolution X-ray structure shows a buried, largely hydrophobic active site in which a conserved glutamate (Glu386) plays a role in recognition of the quaternary ammonium group of the choline substrate. SmCS structurally resembles members of the alkaline phosphatase superfamily, being most closely related to dimeric ASs and tetrameric phosphonate monoester hydrolases. Although >70% of the amino acids between protomers align structurally (RMSDs 1.79-1.99Å), the oligomeric structures show distinctly different packing and protomer-protomer interfaces. The latter also play an important role in active site formation. Mutagenesis of the conserved active site residues typical for ASs, H 2 18 O-labeling studies and the observation of catalytically promiscuous behavior toward phosphoesters confirm the close relation to alkaline phosphatase superfamily members and suggest that SmCS is an AS that catalyzes S-O cleavage in alkyl sulfate esters with extreme catalytic proficiency. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

49 CFR 176.415 - Permit requirements for Division 1.5, ammonium nitrates, and certain ammonium nitrate fertilizers.

Code of Federal Regulations, 2011 CFR

2011-10-01

... nitrates, and certain ammonium nitrate fertilizers. 176.415 Section 176.415 Transportation Other... requirements for Division 1.5, ammonium nitrates, and certain ammonium nitrate fertilizers. (a) Except as... Captain of the Port (COTP). (1) Ammonium nitrate UN1942, ammonium nitrate fertilizers containing more than...

49 CFR 176.415 - Permit requirements for Division 1.5, ammonium nitrates, and certain ammonium nitrate fertilizers.

Code of Federal Regulations, 2013 CFR

2013-10-01

... nitrates, and certain ammonium nitrate fertilizers. 176.415 Section 176.415 Transportation Other... requirements for Division 1.5, ammonium nitrates, and certain ammonium nitrate fertilizers. (a) Except as... Captain of the Port (COTP). (1) Ammonium nitrate UN1942, ammonium nitrate fertilizers containing more than...

49 CFR 176.415 - Permit requirements for Division 1.5, ammonium nitrates, and certain ammonium nitrate fertilizers.

Code of Federal Regulations, 2014 CFR

2014-10-01

... nitrates, and certain ammonium nitrate fertilizers. 176.415 Section 176.415 Transportation Other... requirements for Division 1.5, ammonium nitrates, and certain ammonium nitrate fertilizers. (a) Except as... Captain of the Port (COTP). (1) Ammonium nitrate UN1942, ammonium nitrate fertilizers containing more than...

49 CFR 176.415 - Permit requirements for Division 1.5, ammonium nitrates, and certain ammonium nitrate fertilizers.

Code of Federal Regulations, 2012 CFR

2012-10-01

... nitrates, and certain ammonium nitrate fertilizers. 176.415 Section 176.415 Transportation Other... requirements for Division 1.5, ammonium nitrates, and certain ammonium nitrate fertilizers. (a) Except as... Captain of the Port (COTP). (1) Ammonium nitrate UN1942, ammonium nitrate fertilizers containing more than...

Aryl sulfonate based anticancer alkylating agents.

PubMed

Sheikh, Hamdullah Khadim; Arshad, Tanzila; Kanwal, Ghazala

2018-05-01

This research work revolves around synthesis of antineoplastic alkylating sulfonate esters with dual alkylating sites for crosslinking of the DNA strands. These molecules were evaluated as potential antineoplastic cross linking alkylating agents by reaction with the nucleoside of Guanine DNA nucleobase at both ends of the synthesized molecule. Synthesis of the alkylating molecules and the crosslinking with the guanosine nucleoside was monitored by MALDITOF mass spectroscopy. The synthesized molecule's crosslinking or adduct forming rate with the nucleoside was compared with that of 1,4 butane disulfonate (busulfan), in form of time taken for the appearance of [M+H] + . It was found that aryl sulfonate leaving group was causing higher rate of nucleophilic attack by the Lewis basic site of the nucleobase. Furthermore, the rate was also found to be a function of electron withdrawing or donating nature of the substituent on the aryl ring. Compound with strong electron withdrawing substituent on the para position of the ring reacted fastest. Hence, new alkylating agents were synthesized with optimized or desired reactivity.

Enhancement of alkylation catalysts for improved supercritical fluid regeneration

DOEpatents

Ginosar, Daniel M [Idaho Falls, ID; Petkovic, Lucia [Idaho Falls, ID

2009-09-22

A method of modifying an alkylation catalyst to reduce the formation of condensed hydrocarbon species thereon. The method comprises providing an alkylation catalyst comprising a plurality of active sites. The plurality of active sites on the alkylation catalyst may include a plurality of weakly acidic active sites, intermediate acidity active sites, and strongly acidic active sites. A base is adsorbed to a portion of the plurality of active sites, such as the strongly acidic active sites, selectively poisoning the strongly acidic active sites. A method of modifying the alkylation catalyst by providing an alkylation catalyst comprising a pore size distribution that sterically constrains formation of the condensed hydrocarbon species on the alkylation catalyst or by synthesizing the alkylation catalyst to comprise a decreased number of strongly acidic active sites is also disclosed, as is a method of improving a regeneration efficiency of the alkylation catalyst.

Enhancement of alkylation catalysts for improved supercritical fluid regeneration

DOEpatents

Ginosar, Daniel M.; Petkovic, Lucia M.

2010-12-28

A method of modifying an alkylation catalyst to reduce the formation of condensed hydrocarbon species thereon. The method comprises providing an alkylation catalyst comprising a plurality of active sites. The plurality of active sites on the alkylation catalyst may include a plurality of weakly acidic active sites, intermediate acidity active sites, and strongly acidic active sites. A base is adsorbed to a portion of the plurality of active sites, such as the strongly acidic active sites, selectively poisoning the strongly acidic active sites. A method of modifying the alkylation catalyst by providing an alkylation catalyst comprising a pore size distribution that sterically constrains formation of the condensed hydrocarbon species on the alkylation catalyst or by synthesizing the alkylation catalyst to comprise a decreased number of strongly acidic active sites is also disclosed, as is a method of improving a regeneration efficiency of the alkylation catalyst.

The dehydroalanine effect in the fragmentation of ions derived from polypeptides

PubMed Central

Pilo, Alice L.; Peng, Zhou; McLuckey, Scott A.

2016-01-01

The fragmentation of peptides and proteins upon collision-induced dissociation (CID) is highly dependent on sequence and ion type (e.g. protonated, deprotonated, sodiated, odd electron, etc.). Some amino acids, for example aspartic acid and proline, have been found to enhance certain cleavages along the backbone. Here, we show that peptides and proteins containing dehydroalanine, a non-proteinogenic amino acid with an unsaturated side-chain, undergo enhanced cleavage of the N—Cα bond of the dehydroalanine residue to generate c- and z-ions. Because these fragment ion types are not commonly observed upon activation of positively charged even-electron species, they can be used to identify dehydroalanine residues and localize them within the peptide or protein chain. While dehydroalanine can be generated in solution, it can also be generated in the gas phase upon CID of various species. Oxidized S-alkyl cysteine residues generate dehydroalanine upon activation via highly efficient loss of the alkyl sulfenic acid. Asymmetric cleavage of disulfide bonds upon collisional activation of systems with limited proton mobility also generates dehydroalanine. Furthermore, we show that gas-phase ion/ion reactions can be used to facilitate the generation of dehydroalanine residues via, for example, oxidation of S-alkyl cysteine residues and conversion of multiply-protonated peptides to radical cations. In the latter case, loss of radical side-chains to generate dehydroalanine from some amino acids gives rise to the possibility for residue-specific backbone cleavage of polypeptide ions. PMID:27484024

Extractive alkylation of 6-mercaptopurine and determination in plasma by gas chromatography-mass spectrometry.

PubMed

Floberg, S; Hartvig, P; Lindström, B; Lönner-Holm, G; Odlind, B

1981-09-11

An analytical procedure was developed for the determination of 6-mercaptopurine in plasma. Owing to the polar character and low plasma concentration of the compound, extraction and derivatization was carried out directly from the plasma sample by extractive alkylation. Determination was made using gas chromatography-mass spectrometry with multiple-ion detection. Conditions with respect to the rate of formation and the stability of the derivative formed in the extractive alkylation step were evaluated. The selectively of the method to azathioprine and to metabolites was thoroughly investigated. No 6-mercaptopurine was formed from azathioprine added to water or plasma and run through the method. The method enables the detection of 2 ng of 6 mercaptopurine in a 1.0-ml plasma sample. Quantitative determinations were done down to 10 ng/ml 6 mercaptopurine in plasma.

Infrared spectra of the ammonium ion in ammonium metavanadate NH 4VO 3

NASA Astrophysics Data System (ADS)

de Waal, D.; Heyns, A. M.; Range, K.-J.; Eglmeier, C.

The ND stretching modes of isotopically dilute NH 3D + ions in NH 4VO 3 are in agreement with the predicted splitting into C s, C s and C1(2) components under C s site symmetry for the NH +4 ion. The three bands observed represent the three NH bonding distances in the crystal, and the position, shape and low temperature behaviour of each band confirms the existence of two types of hydrogen bonding in NH 4VO 3. The low temperature infrared modes of NH +4 and ND +4 in NH 4VO 3 and ND 4VO 3, respectively, can be assigned under space group Pbcm. Temperature dependence of these modes also reflects the presence of both normal and bifurcated hydrogen bonds in NH 4VO 3.

Impact of steel slag on the ammonium adsorption by zeolite and a new configuration of zeolite-steel slag substrate for constructed wetlands.

PubMed

Shi, Pengbo; Jiang, Yingbo; Zhu, Hongtao; Sun, Dezhi

2017-07-01

The CaO dissolution from slag, as well as the effects of influencing parameters (i.e. pH and Ca 2+ concentration) on the ammonium adsorption onto zeolite, was systematically studied in this paper. Modeling results of Ca 2+ and OH - release from slag indicated that pseudo-second-order reaction had a better fitness than pseudo-first-order reaction. Changing pH value from 7 to 12 resulted in a drastic reduction of the ammonium adsorption capacity on zeolite, from the peak adsorption capacity at pH 7. High Ca 2+ concentration in solution also inhibited the adsorption of ammonium onto zeolite. There are two proposed mechanisms for steel slag inhibiting the ammonium adsorption capacity of zeolite. On the one hand, OH - released from steel slag can react with ammonium ions to produce the molecular form of ammonia (NH 3 ·H 2 O), which would cause the dissociation of NH 4 + from zeolite. On the other hand, Ca 2+ could replace the NH 4 + ions to adhere onto the surface of zeolite. An innovative substrate filling configuration with zeolite placed upstream of the steel slag was then proposed to eliminate the disadvantageous effects of steel slag. Experimental results showed that this novel filling configuration was superior to two other filling configurations in terms of ammonium removal.

Critical behaviour and vapour-liquid coexistence of 1-alkyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide ionic liquids via Monte Carlo simulations.

PubMed

Rai, Neeraj; Maginn, Edward J

2012-01-01

Atomistic Monte Carlo simulations are used to compute vapour-liquid coexistence properties of a homologous series of [C(n)mim][NTf2] ionic liquids, with n = 1, 2, 4, 6. Estimates of the critical temperatures range from 1190 K to 1257 K, with longer cation alkyl chains serving to lower the critical temperature. Other quantities such as critical density, critical pressure, normal boiling point, and accentric factor are determined from the simulations. Vapour pressure curves and the temperature dependence of the enthalpy of vapourisation are computed and found to have a weak dependence on the length of the cation alkyl chain. The ions in the vapour phase are predominately in single ion pairs, although a significant number of ions are found in neutral clusters of larger sizes as temperature is increased. It is found that previous estimates of the critical point obtained from extrapolating experimental surface tension data agree reasonably well with the predictions obtained here, but group contribution methods and primitive models of ionic liquids do not capture many of the trends observed in the present study

Structure, hydrogen bonding and thermal expansion of ammonium carbonate monohydrate.

PubMed

Fortes, A Dominic; Wood, Ian G; Alfè, Dario; Hernández, Eduardo R; Gutmann, Matthias J; Sparkes, Hazel A

2014-12-01

We have determined the crystal structure of ammonium carbonate monohydrate, (NH4)2CO3·H2O, using Laue single-crystal diffraction methods with pulsed neutron radiation. The crystal is orthorhombic, space group Pnma (Z = 4), with unit-cell dimensions a = 12.047 (3), b = 4.453 (1), c = 11.023 (3) Å and V = 591.3 (3) Å(3) [ρcalc = 1281.8 (7) kg m(-3)] at 10 K. The single-crystal data collected at 10 and 100 K are complemented by X-ray powder diffraction data measured from 245 to 273 K, Raman spectra measured from 80 to 263 K and an athermal zero-pressure calculation of the electronic structure and phonon spectrum carried out using density functional theory (DFT). We find no evidence of a phase transition between 10 and 273 K; above 273 K, however, the title compound transforms first to ammonium sesquicarbonate monohydrate and subsequently to ammonium bicarbonate. The crystallographic and spectroscopic data and the calculations reveal a quite strongly hydrogen-bonded structure (EHB ≃ 30-40 kJ mol(-1)), on the basis of H...O bond lengths and the topology of the electron density at the bond critical points, in which there is no free rotation of the ammonium cation at any temperature. The barrier to free rotation of the ammonium ions is estimated from the observed librational frequency to be ∼ 36 kJ mol(-1). The c-axis exhibits negative thermal expansion, but the thermal expansion behaviour of the a and b axes is ormal.

Structure, hydrogen bonding and thermal expansion of ammonium carbonate monohydrate

PubMed Central

Fortes, A. Dominic; Wood, Ian G.; Alfè, Dario; Hernández, Eduardo R.; Gutmann, Matthias J.; Sparkes, Hazel A.

2014-01-01

We have determined the crystal structure of ammonium carbonate monohydrate, (NH4)2CO3·H2O, using Laue single-crystal diffraction methods with pulsed neutron radiation. The crystal is orthorhombic, space group Pnma (Z = 4), with unit-cell dimensions a = 12.047 (3), b = 4.453 (1), c = 11.023 (3) Å and V = 591.3 (3) Å3 [ρcalc = 1281.8 (7) kg m−3] at 10 K. The single-crystal data collected at 10 and 100 K are complemented by X-ray powder diffraction data measured from 245 to 273 K, Raman spectra measured from 80 to 263 K and an athermal zero-pressure calculation of the electronic structure and phonon spectrum carried out using density functional theory (DFT). We find no evidence of a phase transition between 10 and 273 K; above 273 K, however, the title compound transforms first to ammonium sesquicarbonate monohydrate and subsequently to ammonium bicarbonate. The crystallographic and spectroscopic data and the calculations reveal a quite strongly hydrogen-bonded structure (E HB ≃ 30–40 kJ mol−1), on the basis of H⋯O bond lengths and the topology of the electron density at the bond critical points, in which there is no free rotation of the ammonium cation at any temperature. The barrier to free rotation of the ammonium ions is estimated from the observed librational frequency to be ∼ 36 kJ mol−1. The c-axis exhibits negative thermal expansion, but the thermal expansion behaviour of the a and b axes is ormal. PMID:25449618

49 CFR 176.410 - Division 1.5 materials, ammonium nitrate and ammonium nitrate mixtures.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 2 2011-10-01 2011-10-01 false Division 1.5 materials, ammonium nitrate and ammonium nitrate mixtures. 176.410 Section 176.410 Transportation Other Regulations Relating to... nitrate and ammonium nitrate mixtures. (a) This section prescribes requirements to be observed with...

49 CFR 176.410 - Division 1.5 materials, ammonium nitrate and ammonium nitrate mixtures.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 49 Transportation 2 2012-10-01 2012-10-01 false Division 1.5 materials, ammonium nitrate and ammonium nitrate mixtures. 176.410 Section 176.410 Transportation Other Regulations Relating to... nitrate and ammonium nitrate mixtures. (a) This section prescribes requirements to be observed with...

49 CFR 176.410 - Division 1.5 materials, ammonium nitrate and ammonium nitrate mixtures.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 2 2013-10-01 2013-10-01 false Division 1.5 materials, ammonium nitrate and ammonium nitrate mixtures. 176.410 Section 176.410 Transportation Other Regulations Relating to... nitrate and ammonium nitrate mixtures. (a) This section prescribes requirements to be observed with...

49 CFR 176.410 - Division 1.5 materials, ammonium nitrate and ammonium nitrate mixtures.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 2 2014-10-01 2014-10-01 false Division 1.5 materials, ammonium nitrate and ammonium nitrate mixtures. 176.410 Section 176.410 Transportation Other Regulations Relating to... nitrate and ammonium nitrate mixtures. (a) This section prescribes requirements to be observed with...

Suitability of the methylene blue test for determination of cation exchange capacity of clay minerals related to ammonium acetate method

NASA Astrophysics Data System (ADS)

Milošević, Maja; Logar, Mihovil; Dojčinović, Biljana; Erić, Suzana

2015-04-01

Cation exchange capacity (CEC) represents one of the most important parameters of clay minerals which reflects their ability to exchange cations with liquid phases in near contact. Measurement of CEC is used for characterizing sample plasticity, adsorbing and swelling properties which later define their usage in industrial purposes. Several methods have been developed over the years for determination of layer charge, charge density, charge distribution, etc. and have been published in numerous papers (Czimerova et al., 2006; Yukselen and Kaya, 2008). The main goal of present study is comparison of suitability of more recent method - methylene blue test in regard to older method - ammonium acetate for determination of CEC. For this study, we selected one montmorillonite clay (Bogovina, Serbia) and two mainly kaolinite clays (Miličinica, Serbia). Chemicals used for CEC determinations were solution of methylene blue (MB)(14*10-6M/ml) and ammonium acetate (AA) solution (1M). The obtained results are showing generally lower values in case of MB method. The main difference is due to molecular aggregation of MB on the clay surface. AA method is highly sensitive to the presence of CaO. Release of Ca ion from the sample into the solution can limit the saturation of exchange sites by the ammonium ion. This is clearly visible in case of montmorillonite clay. Fe2+ and Mg ions are difficult to move by the ammonium ion because of their ion radius, but in case of MB molecule there is no such restriction in removing them from the exchange sites. MB solution, even in a low concentration (2*10-6M/ml), is showing preferable results in moving the ions from their positions which is already visible after adding a small quantity of solution (25cm3). Both MB-titration and MB-spot test yield similar results and are much simpler methods than AA and they also give other information such as specific surface area (external and internal) whereas AA method only provides information about

ION EXCHANGE SUBSTANCES BY SAPONIFICATION OF ALLYL PHOSPHATE POLYMERS

DOEpatents

Kennedy, J.

1959-04-14

An ion exchange resin having a relatively high adsorption capacity tor uranyl ion as compared with many common cations is reported. The resin comprises an alphyl-allyl hydrogen phosphate polymer, the alphyl group being either allyl or a lower alkyl group having up to 5 carbon atoins. The resin is prepared by polymerizing compounds such as alkyl-diallyl phosphate and triallyl phosphate in the presence of a free radical generating substance and then partially hydrolyzing the resulting polymer to cause partial replacement of organic radicals by cations. A preferred free radical gencrating agent is dibenzoyl peroxide. The partial hydrolysis is brought about by refluxing the polymer with concentrated aqueous NaOH for three or four hours.

Effects of ammonium-based ionic liquids and 2,4-dichlorophenol on the phospholipid fatty acid composition of zebrafish embryos.

PubMed

Piotrowska, Aleksandra; Syguda, Anna; Wyrwas, Bogdan; Chrzanowski, Lukasz; Luckenbach, Till; Heipieper, Hermann J

2018-01-01

Ionic liquids consisting of a combination of herbicidal anions with a quaternary ammonium cation act as efficient herbicides, which are under consideration to be used in the agriculture. In the present study, we used embryos of the zebrafish (Danio rerio) as a model to assess the toxic potential of ammonium-based ionic liquids for aquatic organisms. As we assumed interference of the partially hydrophobic ionic liquid cation with lipids, we investigated the adaptation response in the lipid composition of the zebrafish embryos, triggered by the ionic compound. Therefore, the impact of ammonium-based ionic liquids with different lengths of the alkyl chain ([C6,C6,C1,C1N][Br], [C8,C8,C1,C1N][Br]) on the phospholipid fatty acid (PLFA) profile of zebrafish embryos up to 72 hours post fertilization (hpf) was examined. Furthermore, the changes in the unsaturation index (UI) of PLFAs, as the sum parameter of membrane fluidity in eukaryotic cells, were presented. The PLFA's UI in the zebrafish embryos upon exposure to quaternary ammonium salts was compared to the UI of the embryos upon exposure to nonionic 2,4-dichlorophenol, which has a similar hydrophobicity but is structurally different to [C8,C8,C1,C1N][Br]. It was shown that for ammonium-based ionic liquid precursors non-specific mode of action occurs and the toxic effect on lipid composition of zebrafish embryos can be well predicted based on chemical properties, like hydrophobicity. Furthermore, the changes in PLFAs, expressed by the UI, can be useful to study toxic effects of organic contamination. However, for zebrafish embryos, after ionic liquids and 2,4-DCP exposure, the changes were observed at high lethal concentrations, which caused the incidence of lethality of 30 and 50% of a group of test animals.

Effects of ammonium-based ionic liquids and 2,4-dichlorophenol on the phospholipid fatty acid composition of zebrafish embryos

PubMed Central

Piotrowska, Aleksandra; Syguda, Anna; Wyrwas, Bogdan; Chrzanowski, Lukasz; Luckenbach, Till

2018-01-01

Ionic liquids consisting of a combination of herbicidal anions with a quaternary ammonium cation act as efficient herbicides, which are under consideration to be used in the agriculture. In the present study, we used embryos of the zebrafish (Danio rerio) as a model to assess the toxic potential of ammonium-based ionic liquids for aquatic organisms. As we assumed interference of the partially hydrophobic ionic liquid cation with lipids, we investigated the adaptation response in the lipid composition of the zebrafish embryos, triggered by the ionic compound. Therefore, the impact of ammonium-based ionic liquids with different lengths of the alkyl chain ([C6,C6,C1,C1N][Br], [C8,C8,C1,C1N][Br]) on the phospholipid fatty acid (PLFA) profile of zebrafish embryos up to 72 hours post fertilization (hpf) was examined. Furthermore, the changes in the unsaturation index (UI) of PLFAs, as the sum parameter of membrane fluidity in eukaryotic cells, were presented. The PLFA’s UI in the zebrafish embryos upon exposure to quaternary ammonium salts was compared to the UI of the embryos upon exposure to nonionic 2,4-dichlorophenol, which has a similar hydrophobicity but is structurally different to [C8,C8,C1,C1N][Br]. It was shown that for ammonium-based ionic liquid precursors non-specific mode of action occurs and the toxic effect on lipid composition of zebrafish embryos can be well predicted based on chemical properties, like hydrophobicity. Furthermore, the changes in PLFAs, expressed by the UI, can be useful to study toxic effects of organic contamination. However, for zebrafish embryos, after ionic liquids and 2,4-DCP exposure, the changes were observed at high lethal concentrations, which caused the incidence of lethality of 30 and 50% of a group of test animals. PMID:29342167

Hydrothermal synthesis of ammonium illite

USGS Publications Warehouse

Šucha, Vladimír; Elsass, F.; Eberl, D.D.; Kuchta, L'.; Madejova, J.; Gates, W.P.; Komadel, P.

1998-01-01

Synthetic gel and glass of illitic composition, natural kaolinite, and mixed-layer illite-smectite were used as starting materials for hydrothermal synthesis of ammonium illite. Ammonium illite was prepared from synthetic gel by hydrothermal treatment at 300??C. The onset of crystallization began within 3 h, and well-crystallized ammonium illite appeared at 24 h. Increasing reaction time (up to four weeks) led to many illite layers per crystal. In the presence of equivalent proportions of potassium and ammonium, the gel was transformed to illite with equimolar contents of K and NH4. In contrast, synthesis using glass under the same conditions resulted in a mixture of mixed-layer ammonium illite-smectite with large expandability and discrete illite. Hydrothermal treatments of the fine fractions of natural kaolinite and illite-smectite produced ammonium illite from kaolinite but the illite-smectite remained unchanged.

Biological alkylation and colloid formation of selenium in methanogenic UASB reactors.

PubMed

Lenz, Markus; Smit, Martijn; Binder, Patrick; van Aelst, Adriaan C; Lens, Piet N L

2008-01-01

Bioalkylation and colloid formation of selenium during selenate removal in upflow anaerobic sludge bed (UASB) bioreactors was investigated. The mesophilic (30 degrees C) UASB reactor (pH = 7.0) was operated for 175 d with lactate as electron donor at an organic loading rate of 2 g COD L(-1) d(-1) and a selenium loading rate of 3.16 mg Se L(-1) d(-1). Combining sequential filtration with ion chromatographic analysis for selenium oxyanions and solid phase micro extraction gas chromatography mass spectrometry (SPME-GC-MS) for alkylated selenium compounds allowed to entirely close the selenium mass balance in the liquid phase for most of the UASB operational runtime. Although selenate was removed to more than 98.6% from the liquid phase, a less efficient removal of dissolved selenium was observed due to the presence of dissolved alkylated selenium species (dimethylselenide and dimethyldiselenide) and colloidal selenium particles in the effluent. The alkylated and the colloidal fractions contributed up to 15 and 31%, respectively, to the dissolved selenium concentration. The size fractions of the colloidal dispersion were: 4 to 0.45 mum: up to 21%, 0.45 to 0.2 mum: up to 11%, and particles smaller than 0.2 mum: up to 8%. Particles of 4 to 0.45 mum were formed in the external settler, but did not settle. SEM-EDX analysis showed that microorganisms form these selenium containing colloidal particles extracellularly on their surface. Lowering the temperature by 10 degrees C for 6 h resulted in drastically reduced selenate removal efficiencies (after a delay of 1.5 d), accompanied by the temporary formation of an unknown, soluble, organic selenium species. This study shows that a careful process control is a prerequisite for selenium treatment in UASB bioreactors, as disturbances in the operational conditions induce elevated selenium effluent concentrations by alkylation and colloid formation.

Silica-Supported, Single-Site Sc and Y Alkyls for Catalytic Hydrogenation of Propylene

DOE Office of Scientific and Technical Information (OSTI.GOV)

Getsoian, Andrew G. Bean; Hu, Bo; Miller, Jeffrey T.

Single site Sc and Y on silica catalysts have been prepared by aqueous and organometallic grafting methods. The former yields Y(III) ions with 5 bonds at an average bond distance of 2.31 Å by X-ray absorption spectroscopy. Although the aqueous synthesis gave single site Y with low coordination number, these were not catalytic for alkane dehydrogenation or olefin hydrogenation. Single site Sc(III) and Y(III) species were also prepared by grafting Sc(CH 2Si(CH 3) 3) 3(THF) 2 and Y(CH 2Si(CH 3) 3) 3(THF) 2, respectively and these are catalysts for olefin hydrogenation at temperatures from about 60 to 100°C; however, theymore » were thermally unstable at higher temperatures necessary for alkane dehydrogenation. The structure of the grafted Y complex was determined by X-ray absorption spectroscopy, IR, and NMR. Grafting lead to protonolysis of 2 of the 3 CH 2Si(CH 3) 3 ligands. Additionally, there was loss of one THF ligand. The EXAFS indicated that there were 4 Y-ligand bonds in the surface species, 2 at 2.16 Å and 2 at 2.39 Å. The metal-alkyl ligand was thought to be necessary for catalytic activity and likely proceeds through a sigma bond metathesis mechanism. In the single site centers without alkyl bonds, Sc and Y ions cannot generate metal-alkyl, or metal-hydride, moieties in situ. We conclude that this is likely due to the very high M-O-Si bond strengths, which must be broken through heterolytic dissociation of C-H bonds during alkane activation for either alkane dehydrogenation or olefin hydrogenation reactions. Lastly, this study demonstrates the importance of pre-catalyst choice versus in situ formation of reactive intermediates to produce active catalysts for alkane bond activation.« less

Silica-Supported, Single-Site Sc and Y Alkyls for Catalytic Hydrogenation of Propylene

DOE PAGES

Getsoian, Andrew G. Bean; Hu, Bo; Miller, Jeffrey T.; ...

2017-09-27

Single site Sc and Y on silica catalysts have been prepared by aqueous and organometallic grafting methods. The former yields Y(III) ions with 5 bonds at an average bond distance of 2.31 Å by X-ray absorption spectroscopy. Although the aqueous synthesis gave single site Y with low coordination number, these were not catalytic for alkane dehydrogenation or olefin hydrogenation. Single site Sc(III) and Y(III) species were also prepared by grafting Sc(CH 2Si(CH 3) 3) 3(THF) 2 and Y(CH 2Si(CH 3) 3) 3(THF) 2, respectively and these are catalysts for olefin hydrogenation at temperatures from about 60 to 100°C; however, theymore » were thermally unstable at higher temperatures necessary for alkane dehydrogenation. The structure of the grafted Y complex was determined by X-ray absorption spectroscopy, IR, and NMR. Grafting lead to protonolysis of 2 of the 3 CH 2Si(CH 3) 3 ligands. Additionally, there was loss of one THF ligand. The EXAFS indicated that there were 4 Y-ligand bonds in the surface species, 2 at 2.16 Å and 2 at 2.39 Å. The metal-alkyl ligand was thought to be necessary for catalytic activity and likely proceeds through a sigma bond metathesis mechanism. In the single site centers without alkyl bonds, Sc and Y ions cannot generate metal-alkyl, or metal-hydride, moieties in situ. We conclude that this is likely due to the very high M-O-Si bond strengths, which must be broken through heterolytic dissociation of C-H bonds during alkane activation for either alkane dehydrogenation or olefin hydrogenation reactions. Lastly, this study demonstrates the importance of pre-catalyst choice versus in situ formation of reactive intermediates to produce active catalysts for alkane bond activation.« less

Improved Electricity Generation by a Microbial Fuel Cell after Pretreatment of Ammonium and Nitrate in Livestock Wastewater with Microbubbles and a Catalyst.

PubMed

Jang, Jae Kyung; Kim, Taeyoung; Kang, Sukwon; Sung, Je Hoon; Kang, Youn Koo; Kim, Young Hwa

2016-11-28

Livestock wastewater containing high concentrations of ammonium and nitrate ions was pretreated with microbubbles and an Fe/MgO catalyst prior to its application in microbial fuel cells because high ion concentrations can interfere with current generation. Therefore, tests were designed to ascertain the effect of pretreatment on current generation. In initial tests, the optimal amount of catalyst was found to be 300 g/l. When 1,000 ml/min O₂ was used as the oxidant, the removal of ammonium- and nitrate-nitrogen was highest. After the operating parameters were optimized, the removal of ammonium and nitrate ions was quantified. The maximum ammonium removal was 32.8%, and nitrate was removed by up to 75.8% at a 500 g/l catalyst concentration over the course of the 2 h reaction time. The current was about 0.5 mA when livestock wastewater was used without pretreatment, whereas the current increased to 2.14 ± 0.08 mA when livestock wastewater was pretreated with the method described above. This finding demonstrates that a 4-fold increase in the current can be achieved when using pretreated livestock wastewater. The maximum power density and current density performance were 10.3 W/m³ and 67.5 A/m³, respectively, during the evaluation of the microbial fuel cells driven by pretreated livestock wastewater.

Intramolecular Diels-Alder Reaction of N-Alkyl-2-cyano-1-azadienes: A Study of the Eschenmoser Cycloreversion of Dihydrooxazines as a Route to N-Alkyl-2-cyano-1-azadienes.

PubMed

Motorina, Irina A.; Fowler, Frank W.; Grierson, David S.

1997-04-04

In connection with the development of the intramolecular Diels-Alder reaction (IMDA) of 1-azadienes, the 5,6-dihydro-4H-1,2-oxazine 12has been evaluated as a synthon equivalent of the 2-cyano-1-azadiene system. It was found that the dihydrooxazonium salt 27, generated in situ from the cyclic hydroxamic acid derivative 26, is converted directly to azadiene 4a via tautomerization to the corresponding enamine and a particularly facile Eschenmoser type cycloreversion process. Conditions were subsequently found for the preparation of synthon 12. N-Alkylation of this intermediate with alkyl bromides in the presence of Ag(+) ion also resulted in direct formation of the 2-cyano-1-azadiene products 38a-dand 4a. Microwave irradiation of a benzene solution of azadiene 4a proved to be a convenient means to effect its IMDA conversion to indolizidine 5a. To avoid decomposition of azadiene 38c, its intramolecular cycloaddition giving 40 (60%) was achieved by flash vacuum thermolysis.

Closed-state inactivation involving an internal gate in Kv4.1 channels modulates pore blockade by intracellular quaternary ammonium ions

PubMed Central

Fineberg, Jeffrey D.; Szanto, Tibor G.; Panyi, Gyorgy; Covarrubias, Manuel

2016-01-01

Voltage-gated K+ (Kv) channel activation depends on interactions between voltage sensors and an intracellular activation gate that controls access to a central pore cavity. Here, we hypothesize that this gate is additionally responsible for closed-state inactivation (CSI) in Kv4.x channels. These Kv channels undergo CSI by a mechanism that is still poorly understood. To test the hypothesis, we deduced the state of the Kv4.1 channel intracellular gate by exploiting the trap-door paradigm of pore blockade by internally applied quaternary ammonium (QA) ions exhibiting slow blocking kinetics and high-affinity for a blocking site. We found that inactivation gating seemingly traps benzyl-tributylammonium (bTBuA) when it enters the central pore cavity in the open state. However, bTBuA fails to block inactivated Kv4.1 channels, suggesting gated access involving an internal gate. In contrast, bTBuA blockade of a Shaker Kv channel that undergoes open-state P/C-type inactivation exhibits fast onset and recovery inconsistent with bTBuA trapping. Furthermore, the inactivated Shaker Kv channel is readily blocked by bTBuA. We conclude that Kv4.1 closed-state inactivation modulates pore blockade by QA ions in a manner that depends on the state of the internal activation gate. PMID:27502553

Control of Diapause by Acidic pH and Ammonium Accumulation in the Hemolymph of Antarctic Copepods

PubMed Central

Schründer, Sabine; Schnack-Schiel, Sigrid B.; Auel, Holger; Sartoris, Franz Josef

2013-01-01

Life-cycles of polar herbivorous copepods are characterised by seasonal/ontogenetic vertical migrations and diapause to survive periods of food shortage during the long winter season. However, the triggers of vertical migration and diapause are still far from being understood. In this study, we test the hypothesis that acidic pH and the accumulation of ammonium (NH4 +) in the hemolymph contribute to the control of diapause in certain Antarctic copepod species. In a recent study, it was already hypothesized that the replacement of heavy ions by ammonium is necessary for diapausing copepods to achieve neutral buoyancy at overwintering depth. The current article extends the hypothesis of ammonium-aided buoyancy by highlighting recent findings of low pH values in the hemolymph of diapausing copepods with elevated ammonium concentrations. Since ammonia (NH3) is toxic to most organisms, a low hemolymph pH is required to maintain ammonium in the less toxic ionized form (NH4 +). Recognizing that low pH values are a relevant factor reducing metabolic rate in other marine invertebrates, the low pH values found in overwintering copepods might not only be a precondition for ammonium accumulation, but in addition, it may insure metabolic depression throughout diapause. PMID:24143238

Nutrient release and ammonium sorption by poultry litter and wood biochars in stormwater treatment.

PubMed

Tian, Jing; Miller, Valentina; Chiu, Pei C; Maresca, Julia A; Guo, Mingxin; Imhoff, Paul T

2016-05-15

The feasibility of using biochar as a filter medium in stormwater treatment facilities was evaluated with a focus on ammonium retention. Successive batch extractions and batch ammonium sorption experiments were conducted in both deionized (DI) water and artificial stormwater using poultry litter (PL) and hardwood (HW) biochars pyrolyzed at 400°C and 500°C. No measureable nitrogen leached from HW biochars except 0.07 μmol/g of org-N from 400°C HW biochar. PL biochar pyrolyzed at 400°C leached 120-127 μmol/g of nitrogen but only 7.1-8.6 μmol/g of nitrogen when pyrolyzed at 500°C. Ammonium sorption was significant for all biochars. At a typical ammonium concentration of 2mg/L in stormwater, the maximum sorption was 150 mg/kg for PL biochar pryolyzed at 400°C. In stormwater, ion competition (e.g. Ca(2+)) suppressed ammonium sorption compared to DI water. Surprisingly, ammonium sorption was negatively correlated to the BET surface area of the tested biochars, but increased linearly with cation exchange capacity. Cation exchange capacity was the primary mechanism controlling ammonium sorption and was enhanced by pyrolysis at 400°C, while BET surface area was enhanced by pyrolysis at 500°C. The optimal properties (BET surface area, CEC, etc.) of biochar as a sorbent are not fixed but depend on the target pollutant. Stormwater infiltration column experiments in sand with 10% biochar removed over 90% of ammonium with influent ammonium concentration of 2mg/L, compared to only 1.7% removal in a sand-only column, indicating that kinetic limitations on sorption were minor for the storm conditions studied. Hardwood and poultry litter biochar pyrolyzed at 500°C and presumably higher temperature may be viable filter media for stormwater treatment facilities, as they showed limited release of organic and inorganic nutrients and acceptable ammonium sorption. Copyright © 2016 Elsevier B.V. All rights reserved.

Ammonium Sulfate Improves Detection of Hydrophilic Quaternary Ammonium Compounds through Decreased Ion Suppression in Matrix-Assisted Laser Desorption/Ionization Imaging Mass Spectrometry.

PubMed

Sugiyama, Eiji; Masaki, Noritaka; Matsushita, Shoko; Setou, Mitsutoshi

2015-11-17

Hydrophilic quaternary ammonium compounds (QACs) include derivatives of carnitine (Car) or choline, which are known to have essential bioactivities. Here we developed a technique for improving the detection of hydrophilic QACs using ammonium sulfate (AS) in matrix-assisted laser desorption/ionization-imaging mass spectrometry (MALDI-IMS). In MALDI mass spectrometry for brain homogenates, the addition of AS greatly increased the signal intensities of Car, acetylcarnitine (AcCar), and glycerophosphocholine (GPC) by approximately 300-, 700-, and 2500-fold. The marked improvement required a higher AS concentration than that needed for suppressing the potassium adduction on phosphatidylcholine and 2,5-dihydroxybenzoic acid. Adding AS also increased the signal intensities of Car, AcCar, and GPC by approximately 10-, 20-, and 40-fold in MALDI-IMS. Consequently, the distributions of five hydrophilic QACs (Car, AcCar, GPC, choline, and phosphocholine) were simultaneously visualized by this technique. The distinct mechanism from other techniques such as improved matrix application, derivatization, or postionization suggests the great potential of AS addition to achieve higher sensitivity of MALDI-IMS for various analytes.

Sorbate-nitrite interactions: acetonitrile oxide as an alkylating agent.

PubMed

Pérez-Prior, M Teresa; Gómez-Bombarelli, Rafael; González-Pérez, Marina; Manso, José A; García-Santos, M Pilar; Calle, Emilio; Casado, Julio

2009-07-01

Because chemical species with DNA-damaging and mutagenic activity are formed in sorbate-nitrite mixtures and because sorbic acid sometimes coexists with nitrite occurring naturally or incorporated as a food additive, the study of sorbate-nitrite interactions is important. Here, the alkylating potential of the products resulting from such interactions was investigated. Drawn were the following conclusions: (i) Acetonitrile oxide (ACNO) is the compound responsible for the alkylating capacity of sorbate-nitrite mixtures; (ii) ACNO alkylates 4-(p-nitrobenzyl)pyridine (NBP), a trap for alkylating agents with nucleophilic characteristics similar to those of DNA bases, forming an adduct (AD; epsilon = 1.4 x 10(4) M(-1) cm(-1); lambda = 519 nm); (iii) the NBP alkylation reaction complies with the rate equation, r = d[AD]/dt = k(alk)(ACNO)[ACNO][NBP]-k(hyd)(AD)[AD], k(alk)(ACNO) being the NBP alkylation rate constant for ACNO and k(hyd)(AD) the rate constant for the adduct hydrolysis reaction; (iv) the small fraction of ACNO forming the adduct with NBP, as well as the small magnitude of the quotient (k(alk) (ACNO)/k(hyd)(ACNO)) as compared with those reported for other alkylating agents, such as some lactones and N-alkyl-N-nitrosoureas, reveals the ACNO effective alkylating capacity to be less significant; (v) the low value of the NBP-ACNO adduct life (defined as the total amount of adduct present along the progression of the NBP alkylation per unit of alkylating agent concentration) points to the high instability of this adduct; and (vi) the obtained results are in accordance with the low carcinogenicity of ACNO.

33 CFR 126.28 - Ammonium nitrate, ammonium nitrate fertilizers, fertilizer mixtures, or nitro carbo nitrate...

Code of Federal Regulations, 2010 CFR

2010-07-01

... nitrate fertilizers, fertilizer mixtures, or nitro carbo nitrate; general provisions. 126.28 Section 126..., ammonium nitrate fertilizers, fertilizer mixtures, or nitro carbo nitrate; general provisions. (a) When any item of ammonium nitrate, ammonium nitrate fertilizers, fertilizer mixtures, or nitro carbo nitrate...

33 CFR 126.28 - Ammonium nitrate, ammonium nitrate fertilizers, fertilizer mixtures, or nitro carbo nitrate...

Code of Federal Regulations, 2014 CFR

2014-07-01

... nitrate fertilizers, fertilizer mixtures, or nitro carbo nitrate; general provisions. 126.28 Section 126..., ammonium nitrate fertilizers, fertilizer mixtures, or nitro carbo nitrate; general provisions. (a) When any item of ammonium nitrate, ammonium nitrate fertilizers, fertilizer mixtures, or nitro carbo nitrate...

33 CFR 126.28 - Ammonium nitrate, ammonium nitrate fertilizers, fertilizer mixtures, or nitro carbo nitrate...

Code of Federal Regulations, 2013 CFR

2013-07-01

... nitrate fertilizers, fertilizer mixtures, or nitro carbo nitrate; general provisions. 126.28 Section 126..., ammonium nitrate fertilizers, fertilizer mixtures, or nitro carbo nitrate; general provisions. (a) When any item of ammonium nitrate, ammonium nitrate fertilizers, fertilizer mixtures, or nitro carbo nitrate...

33 CFR 126.28 - Ammonium nitrate, ammonium nitrate fertilizers, fertilizer mixtures, or nitro carbo nitrate...

Code of Federal Regulations, 2011 CFR

2011-07-01

... nitrate fertilizers, fertilizer mixtures, or nitro carbo nitrate; general provisions. 126.28 Section 126..., ammonium nitrate fertilizers, fertilizer mixtures, or nitro carbo nitrate; general provisions. (a) When any item of ammonium nitrate, ammonium nitrate fertilizers, fertilizer mixtures, or nitro carbo nitrate...

33 CFR 126.28 - Ammonium nitrate, ammonium nitrate fertilizers, fertilizer mixtures, or nitro carbo nitrate...

Code of Federal Regulations, 2012 CFR

2012-07-01

... nitrate fertilizers, fertilizer mixtures, or nitro carbo nitrate; general provisions. 126.28 Section 126..., ammonium nitrate fertilizers, fertilizer mixtures, or nitro carbo nitrate; general provisions. (a) When any item of ammonium nitrate, ammonium nitrate fertilizers, fertilizer mixtures, or nitro carbo nitrate...

Ion distribution in quaternary-ammonium-functionalized aromatic polymers: effects on the ionic clustering and conductivity of anion-exchange membranes.

PubMed

Weiber, E Annika; Jannasch, Patric

2014-09-01

A series of copoly(arylene ether sulfone)s that have precisely two, three, or four quaternary ammonium (QA) groups clustered directly on single phenylene rings along the backbone are studied as anion-exchange membranes. The copolymers are synthesized by condensation polymerizations that involve either di-, tri-, or tetramethylhydroquinone followed by virtually complete benzylic bromination using N-bromosuccinimide and quaternization with trimethylamine. This synthetic strategy allows excellent control and systematic variation of the local density and distribution of QA groups along the backbone. Small-angle X-ray scattering of these copolymers shows extensive ionic clustering, promoted by an increasing density of QA on the single phenylene rings. At an ion-exchange capacity (IEC) of 2.1 meq g(-1), the water uptake decreases with the increasing local density of QA groups. Moreover, at moderate IECs at 20 °C, the Br(-) conductivity of the densely functionalized copolymers is higher than a corresponding randomly functionalized polymer, despite the significantly higher water uptake of the latter. Thus, the location of multiple cations on single aromatic rings in the polymers facilitates the formation of a distinct percolating hydrophilic phase domain with a high ionic concentration to promote efficient anion transport, despite probable limitations by reduced ion dissociation. These findings imply a viable strategy to improve the performance of alkaline membrane fuel cells. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The formation of quasi-alicyclic rings in alkyl-aromatic compounds

NASA Astrophysics Data System (ADS)

Straka, Pavel; Buryan, Petr; Bičáková, Olga

2018-02-01

The alkyl side chains of n-alkyl phenols, n-alkyl benzenes and n-alkyl naphthalenes are cyclised, as demonstrated by GC measurements, FTIR spectroscopy and molecular mechanics calculations. Cyclisation occurs due to the intramolecular interaction between an aromatic ring (-δ) and a hydrogen of the terminal methyl group (+δ) of an alkyl chain. In fact, conventional molecules are not aliphatic-aromatic, but quasi-alicyclic-aromatic. With the aromatic molecules formed with a quasi-alicyclic ring, the effect of van der Waals attractive forces increases not only intramolecularly but also intermolecularly. This effect is strong in molecules with propyl and higher alkyl substituents. The increase of intermolecular van der Waals attractive forces results in bi-linearity in the GC retention time of the compounds in question, observed in the dependence of the logarithm of the relative retention time on the number of carbons in a molecule in both polar and nonpolar stationary phases with both capillary and packed columns. The role of van der Waals forces has been demonstrated using the potential energies of covalent and noncovalent interactions for 2-n-alkyl phenols, n-alkyl benzenes and 1-n-alkyl- and 2-n-alkyl naphthalenes.

21 CFR 184.1135 - Ammonium bicarbonate.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Ammonium bicarbonate. 184.1135 Section 184.1135... Listing of Specific Substances Affirmed as GRAS § 184.1135 Ammonium bicarbonate. (a) Ammonium bicarbonate.... Crystals of ammonium bicarbonate are precipitated from solution and subsequently washed and dried. (b) The...

21 CFR 184.1135 - Ammonium bicarbonate.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ammonium bicarbonate. 184.1135 Section 184.1135... Listing of Specific Substances Affirmed as GRAS § 184.1135 Ammonium bicarbonate. (a) Ammonium bicarbonate.... Crystals of ammonium bicarbonate are precipitated from solution and subsequently washed and dried. (b) The...

21 CFR 184.1135 - Ammonium bicarbonate.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Ammonium bicarbonate. 184.1135 Section 184.1135... Listing of Specific Substances Affirmed as GRAS § 184.1135 Ammonium bicarbonate. (a) Ammonium bicarbonate.... Crystals of ammonium bicarbonate are precipitated from solution and subsequently washed and dried. (b) The...

Cytosine to uracil conversion through hydrolytic deamination of cytidine monophosphate hydroxy-alkylated on the amino group: a liquid chromatography--electrospray ionization--mass spectrometry investigation.

PubMed

Losito, I; Angelico, R; Introna, B; Ceglie, A; Palmisano, F

2012-10-01

A novel pathway for cytosine to uracil conversion performed in a micellar environment, leading to the generation of uridine monophosphate (UMP), was evidenced during the alkylation reaction of cytidine monophosphate (CMP) by dodecyl epoxide. Liquid chromatography-electrospray ionization - ion trap - mass spectrometry was used to separate and identify the reaction products and to follow their formation over time. The detection of hydroxy-amino-dodecane, concurrently with free UMP, in the reaction mixture suggested that, among the various alkyl-derivatives formed, CMP alkylated on the amino group of cytosine could undergo tautomerization to an imine and hydrolytic deamination, generating UMP. Interestingly, no evidence for this peculiar conversion pathway was obtained when guanosine monophosphate (GMP), the complementary ribonucleotide of CMP, was also present in the reaction mixture, due to the fact that NH(2)-alkylated CMP was not formed in this case. The last finding emphasized the role played by CMP-GMP molecular interactions, mediated by a micellar environment, in hindering the alkylation reaction at the level of the cytosine amino group. Copyright © 2012 John Wiley & Sons, Ltd.

Alkylsilyl Peroxides as Alkylating Agents in the Copper-Catalyzed Selective Mono-N-Alkylation of Primary Amides and Arylamines.

PubMed

Sakamoto, Ryu; Sakurai, Shunya; Maruoka, Keiji

2017-07-06

The copper-catalyzed selective mono-N-alkylation of primary amides or arylamines using alkylsilyl peroxides as alkylating agents is reported. The reaction proceeds under mild reaction conditions and exhibits a broad substrate scope with respect to the alkylsilyl peroxides, as well as to the primary amides and arylamines. Mechanistic studies suggest that the present reaction should proceed through a free-radical process that includes alkyl radicals generated from the alkylsilyl peroxides. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Reactions of Tributylstannyl Anioniods with Alkyl Bromides.

DTIC Science & Technology

1981-09-28

g (12 mmol) of cesium tert-butoxide was added to the reaction vessel before the addition of n-butyllithium. Alkylation of Tributylstannyl Anionoids...Dry reaction vessels were purged with argon. The desired alkyl halide (1.0 mmol unless noted) and any desired additive were added to the reaction ...OFFICE OF NAVAL RESEARCH Contract N00014-79-C-0584 Task No. NR 053-714 TECHNICAL REPORT No. 2 Reactions of Tributylstannyl Anionoids with Alkyl

Specific modification of polysulfone with cluster bombardment with assistance of Ar ion irradiation

NASA Astrophysics Data System (ADS)

Xu, Guochun; Hibino, Y.; Awazu, K.; Tanihara, M.; Imanishi, Y.

2000-02-01

Objective: To develop a rapid method for the modification of polysulfone with ammonium sulfamate with the assistance of Ar ion irradiation with a multi-source cluster deposition apparatus. These surfaces mimicking the structure of heparin, a bioactive molecule, have a high anti-thrombosis property. Experimental Design: Polysulfone film, setting on a turning holder, was irradiated by Ar ions during bombardment with ammonium sulfamate clusters. The Ar ion source serves for the activation of a polymer surface and a cluster ion source supplies ammonium sulfamate molecules to react with the activated surface. After thorough washing with de-ionized sterile water, the modified surfaces were evaluated in terms of the contact angle of water, elemental composition, and binding state on electron spectroscopy for chemical analysis and platelet adhesion with platelet rich plasma. Results: The modification of polysulfone decreased the contact angle of water on surfaces from 82.6 ° down to 34.5 °. Ammonium, amine, sulfate, and thiophene combinations were formed on the modified surfaces. The adhesion numbers of the platelet were decreased to one tenth compared to the original surface. The same process was also applied to other polymers such as polyethylene, polypropylene, and polystyrene and similar outcomes were also observed. Conclusion: The primary studies showed successful modification of polysulfone with ammonium sulfamate with the assistance of Ar ion irradiation. Since the same concept can also be applied to other materials with various substrates, combined with the features of no solvent and no topographic changes, this method might be developed into a promising way for modification of polymeric materials.

21 CFR 184.1135 - Ammonium bicarbonate.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Ammonium bicarbonate. 184.1135 Section 184.1135... GRAS § 184.1135 Ammonium bicarbonate. (a) Ammonium bicarbonate (NH4HCO3, CAS Reg. No. 1066-33-7) is prepared by reacting gaseous carbon dioxide with aqueous ammonia. Crystals of ammonium bicarbonate are...

Recombination of electrons with NH4/+/-/NH3/n-series ions

NASA Technical Reports Server (NTRS)

Huang, C.-M.; Biondi, M. A.; Johnsen, R.

1976-01-01

The paper examines the recombination of electrons with ammonium-series cluster ions, NH4(+)-(NH3)n, for two reasons: (1) NH4(+) may be a significant ion in the lower atmospheres of the earth and the outer planets, and (2) to investigate the weak temperature dependence of the cluster ion's recombination coefficient. A microwave afterglow mass spectrometer was used to determine the recombination coefficients for the first five members of the ammonium series, (18+) through (86+), at temperatures between 200 and 410 K. The electron temperature dependence of the recombination coefficient was determined for (35+) and (52+), the n = 1 and 2 cluster ions, over the temperature range 300-3000 K.

Alkylation Damage by Lipid Electrophiles Targets Functional Protein Systems*

PubMed Central

Codreanu, Simona G.; Ullery, Jody C.; Zhu, Jing; Tallman, Keri A.; Beavers, William N.; Porter, Ned A.; Marnett, Lawrence J.; Zhang, Bing; Liebler, Daniel C.

2014-01-01

Protein alkylation by reactive electrophiles contributes to chemical toxicities and oxidative stress, but the functional impact of alkylation damage across proteomes is poorly understood. We used Click chemistry and shotgun proteomics to profile the accumulation of proteome damage in human cells treated with lipid electrophile probes. Protein target profiles revealed three damage susceptibility classes, as well as proteins that were highly resistant to alkylation. Damage occurred selectively across functional protein interaction networks, with the most highly alkylation-susceptible proteins mapping to networks involved in cytoskeletal regulation. Proteins with lower damage susceptibility mapped to networks involved in protein synthesis and turnover and were alkylated only at electrophile concentrations that caused significant toxicity. Hierarchical susceptibility of proteome systems to alkylation may allow cells to survive sublethal damage while protecting critical cell functions. PMID:24429493

Alkylating agents for Waldenstrom's macroglobulinaemia.

PubMed

Yang, Kun; Tan, Jianlong; Wu, Taixiang

2009-01-21

Waldenstrom's macroglobulinaemia (WM) is an uncommon B-cell lymphoproliferative disorder characterized by bone marrow infiltration and production of monoclonal immunoglobulin. Uncertainty remains if alkylating agents, such as chlorambucil, melphalan or cyclophosphamide, are an effective form of management. To assess the effects and safety of the alkylating agents on Waldenstrom's macroglobulinaemia (WM). We searched the Cochrane Central Register of Controlled Trials (Issue 1, 2008), MEDLINE (1966 to 2008), EMBASE (1980 to 2008), the Chinese Biomedical Base (1982 to 2008) and reference lists of articles.We also handsearched relevant conference proceedings from 1990 to 2008. Randomised controlled trials (RCTs) comparing alkylating agents given concomitantly with radiotherapy, splenectomy, plasmapheresis, stem-cell transplantation in patients with a confirmed diagnosis of WM. Two authors independently assessed trial quality and extracted data. We contacted study authors for additional information. We collected adverse effects information from the trials. One trial involving 92 participants with pretreated/relapsed WM compared the effect of fludarabine versus the combination of cyclophosphamide (the alkylating agent), doxorubicin and prednisone (CAP). Compared to CAP, the Hazard ratio (HR) for deaths of treatment with fludarabine was estimated to be 1.04, with a standard error of 0.30 (95% CI 0.58 to 1.48) and it indicated that the mean difference of median survival time was -4.00 months, and 16.00 months for response duration. The relative risks (RR) of response rate was 2.80 (95% CI 1.10 to 7.12). There were no statistically difference in overall survival rate and median survival months, while on the basis of response rate and response duration, fludarabine seemed to be superior to CAP for pretreated/relapsed patients with macroglobulinaemia. Although alkylating agents have been used for decades they have never actually been tested in a proper randomised trial. This

21 CFR 184.1137 - Ammonium carbonate.

Code of Federal Regulations, 2011 CFR

2011-04-01

...). It is prepared by the sublimation of a mixture of ammonium sulfate and calcium carbonate and occurs... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Ammonium carbonate. 184.1137 Section 184.1137 Food... Specific Substances Affirmed as GRAS § 184.1137 Ammonium carbonate. (a) Ammonium carbonate ((NH4)2CO3, CAS...

21 CFR 184.1137 - Ammonium carbonate.

Code of Federal Regulations, 2010 CFR

2010-04-01

...). It is prepared by the sublimation of a mixture of ammonium sulfate and calcium carbonate and occurs... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ammonium carbonate. 184.1137 Section 184.1137 Food... Specific Substances Affirmed as GRAS § 184.1137 Ammonium carbonate. (a) Ammonium carbonate ((NH4)2CO3, CAS...

21 CFR 184.1137 - Ammonium carbonate.

Code of Federal Regulations, 2013 CFR

2013-04-01

...). It is prepared by the sublimation of a mixture of ammonium sulfate and calcium carbonate and occurs... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Ammonium carbonate. 184.1137 Section 184.1137 Food... Specific Substances Affirmed as GRAS § 184.1137 Ammonium carbonate. (a) Ammonium carbonate ((NH4)2CO3, CAS...

21 CFR 184.1138 - Ammonium chloride.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ammonium chloride. 184.1138 Section 184.1138 Food... Specific Substances Affirmed as GRAS § 184.1138 Ammonium chloride. (a) Ammonium chloride (NH4Cl, CAS Reg. No. 12125-02-9) is produced by the reaction of sodium chloride and an ammonium salt in solution. The...

From Broad-Spectrum Biocides to Quorum Sensing Disruptors and Mussel Repellents: Antifouling Profile of Alkyl Triphenylphosphonium Salts

PubMed Central

Martín-Rodríguez, Alberto J.; Babarro, Jose M. F.; Lahoz, Fernando; Sansón, Marta; Martín, Víctor S.; Norte, Manuel; Fernández, José J.

2015-01-01

‘Onium’ compounds, including ammonium and phosphonium salts, have been employed as antiseptics and disinfectants. These cationic biocides have been incorporated into multiple materials, principally to avoid bacterial attachment. In this work, we selected 20 alkyl-triphenylphosphonium salts, differing mainly in the length and functionalization of their alkyl chains, in fulfilment of two main objectives: 1) to provide a comprehensive evaluation of the antifouling profile of these molecules with relevant marine fouling organisms; and 2) to shed new light on their potential applications, beyond their classic use as broad-spectrum biocides. In this regard, we demonstrate for the first time that these compounds are also able to act as non-toxic quorum sensing disruptors in two different bacterial models (Chromobacterium violaceum and Vibrio harveyi) as well as repellents in the mussel Mytilus galloprovincialis. In addition, their inhibitory activity on a fouling-relevant enzymatic model (tyrosinase) is characterized. An analysis of the structure-activity relationships of these compounds for antifouling purposes is provided, which may result useful in the design of targeted antifouling solutions with these molecules. Altogether, the findings reported herein provide a different perspective on the biological activities of phosphonium compounds that is particularly focused on, but, as the reader will realize, is not limited to their use as antifouling agents. PMID:25897858

Application of anaerobic ammonium-oxidizing consortium to achieve completely autotrophic ammonium and sulfate removal.

PubMed

Liu, Sitong; Yang, Fenglin; Gong, Zheng; Meng, Fangang; Chen, Huihui; Xue, Yuan; Furukawa, Kenji

2008-10-01

The simultaneous ammonium and sulfate removal was detected in an anammox reactor, consisted of ammonium oxidization with sulfate deoxidization, and subsequently traditional anammox process, in via of middle medium nitrite with solid sulfur and N2 as the terminal products. The pure anammox bacteria offered a great biotechnological potential for the completely autotrophic reaction indicated by batch tests. Denaturing gradient gel electrophoresis (DGGE) analysis further revealed that a new organism belonging to Planctomycetales was strongly enriched in the defined niche: the redox of ammonium and sulfate. The new species "Anammoxoglobussulfate" was so considered as holding a critical role in the ammonium oxidization with sulfate deoxidization to nitrite. Afterwards, the Planctomyces existing in the bacteria community performed the anammox process together to achieve the complete nitrogen and sulfate removal. The potential use of sulfate as electron acceptor for ammonium oxidizing widens the usage of anammox bacteria.

Biodegradability and aquatic toxicity of quaternary ammonium-based gemini surfactants: Effect of the spacer on their ecological properties.

PubMed

Garcia, M Teresa; Kaczerewska, Olga; Ribosa, Isabel; Brycki, Bogumił; Materna, Paulina; Drgas, Małgorzata

2016-07-01

Aerobic biodegradability and aquatic toxicity of five types of quaternary ammonium-based gemini surfactants have been examined. The effect of the spacer structure and the head group polarity on the ecological properties of a series of dimeric dodecyl ammonium surfactants has been investigated. Standard tests for ready biodegradability assessment (OECD 310) were conducted for C12 alkyl chain gemini surfactants containing oxygen, nitrogen or a benzene ring in the spacer linkage and/or a hydroxyethyl group attached to the nitrogen atom of the head groups. According to the results obtained, the gemini surfactants examined cannot be considered as readily biodegradable compounds. The negligible biotransformation of the gemini surfactants under the standard biodegradation test conditions was found to be due to their toxic effects on the microbial population responsible for aerobic biodegradation. Aquatic toxicity of gemini surfactants was evaluated against Daphnia magna. The acute toxicity values to Daphnia magna, IC50 at 48 h exposure, ranged from 0.6 to 1 mg/L. On the basis of these values, the gemini surfactants tested should be classified as toxic or very toxic to the aquatic environment. However, the dimeric quaternary ammonium-based surfactants examined result to be less toxic than their corresponding monomeric analogs. Nevertheless the aquatic toxicity of these gemini surfactants can be reduced by increasing the molecule hydrophilicity by adding a heteroatom to the spacer or a hydroxyethyl group to the polar head groups. Copyright © 2016 Elsevier Ltd. All rights reserved.

Alkyl phosphonic acids and sulfonic acids in the Murchison meteorite

NASA Technical Reports Server (NTRS)

Cooper, George W.; Onwo, Wilfred M.; Cronin, John R.

1992-01-01

Homologous series of alkyl phosphonic acids and alkyl sulfonic acids, along with inorganic orthophosphate and sulfate, are identified in water extracts of the Murchison meteorite after conversion to their t-butyl dimethylsilyl derivatives. The methyl, ethyl, propyl, and butyl compounds are observed in both series. Five of the eight possible alkyl phosphonic acids and seven of the eight possible alkyl sulfonic acids through C4 are identified. Abundances decrease with increasing carbon number as observed of other homologous series indigenous to Murchison. Concentrations range downward from approximately 380 nmol/gram in the alkyl sulfonic acid series, and from 9 nmol/gram in the alkyl phosphonic acid series.

Disinfection of Water with Quaternary Ammonium Salts Insolubilized on a Porous Glass Surface

PubMed Central

Nakagawa, Yoshihiro; Hayashi, Hiroyuki; Tawaratani, Takahiko; Kourai, Hiroki; Horie, Tokunaru; Shibasaki, Isao

1984-01-01

Insoluble quaternary ammonium salts bound to porous glass showed antibacterial activity. An agent designated as G12, which had a dodecyl alkyl chain, was selected for some antibacterial tests on comparison of it with the agent reported previously. The antibacterial activity of G12 toward Escherichia coli was mainly due to the adsorption of cells and therefore gradually decreased during continuous treatment of a cell suspension. The lost G12 activity was completely recovered by washing with ethanol, and the activity of refreshed G12 decreased in the same manner as that of fresh G12. The lost activity was, however, always recovered only by ethanol treatment. This indicated that G12 might interact with cells more strongly by means of a hydrophobic force than an electrostatic one. The antimicrobial spectrum showed that G12 was effective against not only bacteria but also yeasts. PMID:16346491

21 CFR 184.1137 - Ammonium carbonate.

Code of Federal Regulations, 2014 CFR

2014-04-01

... sublimation of a mixture of ammonium sulfate and calcium carbonate and occurs as a white powder or a hard... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Ammonium carbonate. 184.1137 Section 184.1137 Food... GRAS § 184.1137 Ammonium carbonate. (a) Ammonium carbonate ((NH4)2CO3, CAS Reg. No. 8000-73-5) is a...

Effect of ammonium carbonate to metal ions molar ratio on synthesis and sintering of Nd:YAG nanopowders

NASA Astrophysics Data System (ADS)

Liu, Qiang; Chen, Cong; Dai, Jiawei; Hu, Zewang; Chen, Haohong; Li, Jiang

2018-06-01

Using the nanopowders synthesized by a reverse co-precipitation method, neodymium doped yttrium aluminum garnet (Nd:YAG) transparent ceramics were fabricated by vacuum sintering method. The influence of ammonium carbonate to metal ions (NH4HCO3/M3+) molar ratio (R value) on the properties of Nd:YAG precursors and powders, as well as the densification, microstructure, and transmittance of the resultant ceramics was systematically investigated. The results show that the precursors have similar compositions and the calcined powders have pure Y3Al5O12 (YAG) phase. However, the R value is closely related to the morphologies of the precursors and powders. It is found that the powder with R = 3.0 has strongest agglomeration and the powders with R = 3.2-4.0 show better dispersity. Using these powders as starting materials, the corresponding ceramics were sintered at 1720 °C for 20 h in vacuum. As a result, the ceramic with R = 3.2 obtains the best transmittance of about 72% at the wavelength of 1064 nm. The grain growth exponent and activation energy of the Nd:YAG ceramics fabricated from the powder with R = 3.2 were also studied.

40 CFR 721.2420 - Alkoxylated dialkyldiethylenetriamine, alkyl sulfate salt.

Code of Federal Regulations, 2013 CFR

2013-07-01

..., alkyl sulfate salt. 721.2420 Section 721.2420 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.2420 Alkoxylated dialkyldiethylenetriamine, alkyl sulfate salt. (a... generically as an alkoxylated dialkyldiethylenetriamine, alkyl sulfate salt (PMN P-91-288) is subject to...

40 CFR 721.2420 - Alkoxylated dialkyldiethylenetriamine, alkyl sulfate salt.

Code of Federal Regulations, 2011 CFR

2011-07-01

..., alkyl sulfate salt. 721.2420 Section 721.2420 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.2420 Alkoxylated dialkyldiethylenetriamine, alkyl sulfate salt. (a... generically as an alkoxylated dialkyldiethylenetriamine, alkyl sulfate salt (PMN P-91-288) is subject to...

40 CFR 721.2410 - Alkoxylated alkyldiethylenetriamine, alkyl sulfate salts.

Code of Federal Regulations, 2013 CFR

2013-07-01

..., alkyl sulfate salts. 721.2410 Section 721.2410 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.2410 Alkoxylated alkyldiethylenetriamine, alkyl sulfate salts. (a... generically as alkoxylated dialkyldiethylenetriamine, alkyl sulfate salts (PMN P-94-325, 326, and 327) are...

40 CFR 721.2410 - Alkoxylated alkyldiethylenetriamine, alkyl sulfate salts.

Code of Federal Regulations, 2012 CFR

2012-07-01

..., alkyl sulfate salts. 721.2410 Section 721.2410 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.2410 Alkoxylated alkyldiethylenetriamine, alkyl sulfate salts. (a... generically as alkoxylated dialkyldiethylenetriamine, alkyl sulfate salts (PMN P-94-325, 326, and 327) are...

40 CFR 721.2420 - Alkoxylated dialkyldiethylenetriamine, alkyl sulfate salt.

Code of Federal Regulations, 2014 CFR

2014-07-01

..., alkyl sulfate salt. 721.2420 Section 721.2420 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.2420 Alkoxylated dialkyldiethylenetriamine, alkyl sulfate salt. (a... generically as an alkoxylated dialkyldiethylenetriamine, alkyl sulfate salt (PMN P-91-288) is subject to...

40 CFR 721.2420 - Alkoxylated dialkyldiethylenetriamine, alkyl sulfate salt.

Code of Federal Regulations, 2012 CFR

2012-07-01

..., alkyl sulfate salt. 721.2420 Section 721.2420 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.2420 Alkoxylated dialkyldiethylenetriamine, alkyl sulfate salt. (a... generically as an alkoxylated dialkyldiethylenetriamine, alkyl sulfate salt (PMN P-91-288) is subject to...

40 CFR 721.2410 - Alkoxylated alkyldiethylenetriamine, alkyl sulfate salts.

Code of Federal Regulations, 2011 CFR

2011-07-01

..., alkyl sulfate salts. 721.2410 Section 721.2410 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.2410 Alkoxylated alkyldiethylenetriamine, alkyl sulfate salts. (a... generically as alkoxylated dialkyldiethylenetriamine, alkyl sulfate salts (PMN P-94-325, 326, and 327) are...

40 CFR 721.2410 - Alkoxylated alkyldiethylenetriamine, alkyl sulfate salts.

Code of Federal Regulations, 2014 CFR

2014-07-01

..., alkyl sulfate salts. 721.2410 Section 721.2410 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.2410 Alkoxylated alkyldiethylenetriamine, alkyl sulfate salts. (a... generically as alkoxylated dialkyldiethylenetriamine, alkyl sulfate salts (PMN P-94-325, 326, and 327) are...

Polymerization of Conducting Polymers Confined to Free Surfaces: A comparison of the Langmuir-Blodgett Polymerization of 3-Alkyl Pyrroles and 2- Alkyl Anilines

DTIC Science & Technology

1992-05-19

Confined to Free Surfaces: A Comparison of the Langmuir-Blodgett Polymerization of 3- Alkyl Pyrroles and 2- Alkyl Anilines Submitted for Publication in...Surfaces: A Comparison of the Langmuir Blodgett Polymerizations of 3- alkyl pyrroles and 2- alkyl anilines R. S. Duran and H.C. Zhou Dept. of Chemistry...polymerization reactions in more detail and compare them. To do this, the polymerization reactions were run under two conditions. In the first case

21 CFR 176.120 - Alkyl ketene dimers.

Code of Federal Regulations, 2011 CFR

2011-04-01

... section. (a) The alkyl ketene dimers are manufactured by the dehydrohalogenation of the acyl halides derived from the fatty acids of animal or vegetable fats and oils. (b) The alkyl ketene dimers are used as...

Chemistry of alkali cation exchanged faujasite and mesoporous NaX using alkyl halides and phosphates

NASA Astrophysics Data System (ADS)

Lee, Min-Hong

The purpose of this work was to increase the reactivity of Faujasite X (NaX) zeolite toward the reactive decontamination of materials subject to nucleophilic attack by means of zeolite cation optimization and by means of the synthesis of mesoporous Faujasite X. Primary alkyl halides and trialkyl phosphates have been the test materials on which the cation-optimized and mesoporous zeolites have been tested. In the alkali cation optimization work, reactions of methyl iodide and 1-chloropropane with alkali metal cation exchanged Faujasite zeolite X were investigated at room temperature. The reactivity of the framework and the product formation were shown to depend on zeolite framework counter-cation. A quantitative study of zeolite product formation has been carried out, primarily using solid-state NMR spectroscopy. Large alkali cations showed preference toward substitution chemistry. In contrast, alkyl halide exposed LiX and NaX zeolites underwent both substitution and elimination. Subsequently introduced water molecules led to hydrolysis of framework species that was sensitive to framework counter-cation. The mesoporous NaX zeolites work undertakes to test whether an improvement in surface chemical reactivity can be achieved by introducing mesopores into the already reactive nucleophilic microporous NaX zeolite. Incorporation of the polydiallyl dimethyl ammonium chloride (PDADMAC) template and the formation of mesopores in Faujasite X zeolite (NaX) were successful and well-characterized. The mesopores are proposed to have occurred from incorporation of the cationic PDADMAC polymer into the zeolite by compensating zeolite framework charge. Subsequent sodium cation exchange of calcined mesoporous NaX was shown to restore the chemical reactivity characteristic of as-synthesized NaX. Trialkyl organophosphorous compounds underwent substitution reactions. The reactivity of both microporous and mesoporous Faujasite zeolite X and the product formation was shown to depend on

A Concentration-Dependent Insulin Immobilization Behavior of Alkyl-Modified Silica Vesicles: The Impact of Alkyl Chain Length.

PubMed

Zhang, Jun; Zhang, Long; Lei, Chang; Huang, Xiaodan; Yang, Yannan; Yu, Chengzhong

2018-05-01

The insulin immobilization behaviors of silica vesicles (SV) before and after modification with hydrophobic alkyl -C 8 and -C 18 groups have been studied and correlated to the grafted alkyl chain length. In order to minimize the influence from the other structural parameters, monolayered -C 8 or -C 18 groups are grafted onto SV with controlled density. The insulin immobilization capacity of SV is dependent on the initial insulin concentrations (IIC). At high IIC (2.6-3.0 mg/mL), the trend of insulin immobilization capacity of SV is SV-OH > SV-C 8 > SV-C 18 , which is determined mainly by the surface area of SV. At medium IIC (0.6-1.9 mg/mL), the trend changes to SV-C 8 ≥ SV-C 18 > SV-OH as both the surface area and alkyl chain length contribute to the insulin immobilization. At an extremely low IIC, the hydrophobic-hydrophobic interaction between the alkyl group and insulin molecules plays the most significant role. Consequently, SV-C 18 with longer alkyl groups and the highest hydrophobicity show the best insulin enrichment performance compared to SV-C 8 and SV-OH, as evidenced by an insulin detection limit of 0.001 ng/mL in phosphate buffered saline (PBS) and 0.05 ng/mL in artficial urine determined by mass spectrometry (MS).

IONIC LIQUID-CATALYZED ALKYLATION OF ISOBUTANE WITH 2-BUTENE

EPA Science Inventory

A detailed study of the alkylation of isobutane with 2-butene in ionic liquid media has been conducted using 1-alkyl-3-methylimidazolium halides?aluminum chloride encompassing various alkyl groups (butyl-, hexyl-, and octyl-) and halides (Cl, Br, and I) on its cations and anions,...

Properties of Ammonium Ion–Water Clusters: Analyses of Structure Evolution, Noncovalent Interactions, and Temperature and Humidity Effects

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pei, Shi-Tu; Jiang, Shuai; Liu, Yi-Rong

2015-03-03

Although ammonium ion–water clusters are abundant in the biosphere, some information regarding these clusters, such as their growth route, the influence of temperature and humidity, and the concentrations of various hydrated clusters, is lacking. In this study, theoretical calculations are performed on ammonium ion–water clusters. These theoretical calculations are focused on determining the following characteristics: (1) the pattern of cluster growth; (2) the percentages of clusters of the same size at different temperatures and humidities; (3) the distributions of different isomers for the same size clusters at different temperatures; (4) the relative strengths of the noncovalent interactions for clusters ofmore » different sizes. The results suggest that the dipole moment may be very significant for the ammonium ion–water system, and some new stable isomers were found. The nucleation of ammonium ions and water molecules is favorable at low temperatures; thus, the clusters observed at high altitudes might not be present at low altitudes. High humidity can contribute to the formation of large ammonium ion–water clusters, whereas the formation of small clusters may be favorable under low-humidity conditions. The potential energy surfaces (PES) of these different sized clusters are complicated and differ according to the distribution of isomers at different temperatures. Some similar structures are observed between NH4+(H2O)n and M(H2O)n (where M represents an alkali metal ion or water molecule); when n = 8, the clusters begin to form the closed-cage geometry. As the cluster size increases, these interactions become progressively weaker. The successive binding energy at the DF-MP2-F12/VDZ-F12 level is better than that at the PW91PW91/6-311++G(3df, 3pd) level and is consistent with the experimentally determined values.« less

Geoelectrical Monitoring of Ammonium Sorption Processes in a Biochar Filtration System

NASA Astrophysics Data System (ADS)

Wang, S. L.; Osei, C.; Rabinovich, A.; Ntarlagiannis, D.; Rouff, A.

2017-12-01

With the rise of modern agriculture, nutrient pollution has become an increasingly important environmental concern. A common problem is excess nitrogen which agricultural livestock farms often generate in the form of ammonium (NH4+). This highly soluble ion is easily transported through runoff and leaching, leading to water supply contamination and soil fertility decline. Biochar is the carbon-rich product of thermal decomposition of biomass in an oxygen-free environment. It is primarily used as a soil enhancer with other applications currently under research. Biochar's unique characteristics such as high surface area, high sorption capacity and long term biological and chemical stability make it a prime candidate for environmental applications such as contaminant regulation and waste effluent treatment. The spectral induced polarization (SIP) method is an established geoelectrical method that has been increasingly used in environmental investigations. SIP is unique among geophysical methods because it is sensitive not only to the bulk properties of the medium under investigation but also to the interfacial properties (e.g., mineral-fluid). The unique properties that make biochar attractive for environmental use are associated with surface properties (e.g., surface area, surface charge, presence of functional groups) that are expected to have a profound effect on SIP signals. This study presents early results on the use of the SIP method to monitor ammonium recycling of swine wastewater in a biochar filtration system. SIP measurements were taken continuously as biochar-packed columns were first injected with an ammonium wastewater solution (sorption phase) and then an ammonium-free solution (desorption phase). Geochemical monitoring showed that outflow ammonium concentration decreased during the sorption phase and increased during the desorption phase. The collected SIP data appear to be in agreement with the geochemical monitoring, providing a temporally

40 CFR 721.1878 - Alkali metal alkyl borohydride (generic).

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Alkali metal alkyl borohydride... Specific Chemical Substances § 721.1878 Alkali metal alkyl borohydride (generic). (a) Chemical substance... alkali metal alkyl borohydride (PMN P-00-1089) is subject to reporting under this section for the...

40 CFR 721.1878 - Alkali metal alkyl borohydride (generic).

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Alkali metal alkyl borohydride... Specific Chemical Substances § 721.1878 Alkali metal alkyl borohydride (generic). (a) Chemical substance... alkali metal alkyl borohydride (PMN P-00-1089) is subject to reporting under this section for the...

Infrared spectroscopic study of SO₄²⁻ ions included in M'₂M''(SeO₄)₂⋅6H₂O (Me'=K, NH₄⁺; M''=Mg, Co, Ni, Cu, Zn) and NH₄⁺ ions included in K₂M(XO₄)₂⋅6H₂O (X=S, Se; M''=Mg, Co, Ni, Cu, Zn).

PubMed

Marinova, D; Karadjova, V; Stoilova, D

2015-01-05

Infrared spectra of Tutton compounds, M'₂M''(SeO₄)₂⋅6H₂O (M'=K, NH₄⁺; M''=Mg, Co, Ni, Cu, Zn; X=S, Se), as well as those of SO₄²⁻ guest ions included in selenate host lattices and of NH4(+) guest ions included in potassium host lattices are presented and discussed in the regions of ν₃ and ν₁ of SO₄²⁻ guest ions, ν₄ of NH₄⁺ guest ions and water librations. The SO₄²⁻ guest ions matrix-isolated in selenate matrices (approximately 2 mol%) exhibit three bands corresponding to ν₃ and one band corresponding to ν₁ in good agreement with the low site symmetry C₁ of the host selenate ions. When the larger SO₄²⁻ ions are replaced by the smaller SO₄²⁻ ions the mean values of the asymmetric stretching modes ν₃ of the included SO₄²⁻ ions are slightly shifted to lower frequencies as compared to those of the same ions in the neat sulfate compounds due to the smaller repulsion potential of the selenate matrices (larger unit-cell volumes of the selenates). It has been established that the extent of energetic distortion of the sulfate ions matrix-isolated in the ammonium selenates as deduced from the values of Δν₃ and Δν₃/νc is stronger than that of the same ions matrix-isolated in the potassium selenates due to the formation of hydrogen bonds between the SO₄²⁻ guest ions with both the water molecules in the host compounds and the NH₄⁺ host ions (for example, Δν₃ of the sulfate guest ions have values of 30 and 51 cm(-1) in the nickel potassium and ammonium compounds, and 33 and 49 cm(-1) in the zinc potassium and ammonium compounds, respectively). The infrared spectra of ammonium doped potassium sulfate matrices show three bands corresponding to Δν₄ of the included ammonium ions in agreement with the low site symmetry C₁ of the host potassium ions. However, the inclusion of ammonium ions in selenate matrices (with exception of the magnesium compound) leads to the appearance of four bands

Renal ammonium production--une vue canadienne.

PubMed

Brosnan, J T; Lowry, M; Vinay, P; Gougoux, A; Halperin, M L

1987-04-01

The purpose of this review is to examine the factors regulating ammonium production in the kidney and to place these factors in the perspective of acid-base balance. Renal ammonium production and excretion are required to maintain acid-base balance. However, only a portion of renal ammonium production is specifically stimulated by metabolic acidosis. One should examine urinary ammonium excretion at three levels: distribution of ammonium between blood and urine, augmented glutamine metabolism, and an energy constraint due to ATP balance considerations. With respect to the biochemical regulation of acid-base renal ammonium production, an acute stimulation of alpha-ketoglutarate dehydrogenase by a fall in pH seems to be important but this may not be the entire story. In chronic metabolic acidosis augmented glutamine entry into mitochondria (dog) or increased phosphate-dependent glutaminase activity (rat) become critical to support a high flux rate. Metabolic alterations, which diminish the rate of oxidation of alternate fuels, might also be important. The above principles are discussed in the ketoacidosis of fasting, the clinically important situation of high rates of renal ammonium production.

Extended 3{beta}-alkyl steranes and 3-alkyl triaromatic steroids in crude oils and rock extracts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dahl, J.; Moldowan, J.M.; Summons, R.E.

1995-09-01

In oils and Precambian- to Miocene-age source rocks from varying depositional environments, we have conclusively identified several novel 3-alkyl sterane and triaromatic steroid series, including (1) 3{beta}-n-pentyl steranes, (2) 3{beta}-isopentyl steranes, (3) 3{beta}-n-hexyl steranes, (4) 3{beta}-n-hepatyl steranes, (5) 3,4-dimethyl steranes, (6) 3{beta}-butyl,4-methyl steranes, (7) triaromatic 3-n-pentyl steroids, and (8) triaromatic 3-isopentyl steroids. We have also tentatively identified additional homologs with 3-alkyl substituents as large as C{sub 11}. The relative abundances of these compounds vary substantially between samples, as indicated by (1) the ratio of 3{beta}-n-pentyl steranes to 3{beta}-isopentyl steranes and (2) the ratio of 3-n-pentyl triaromatic steroids to 3-isopentyl triaromaticmore » steroids. These data suggest possible utility for these parameters as tools for oil-source rock correlations and reconstruction of depositional environments. Although no 3-alkyl steroid natural products are currently known, several lines of evidence suggest that 3{beta}-alkyl steroids result from bacterial side-chain additions to diagenetic {delta}{sup 2}-sterenes.« less

Peptides derivatized with bicyclic quaternary ammonium ionization tags. Sequencing via tandem mass spectrometry.

PubMed

Setner, Bartosz; Rudowska, Magdalena; Klem, Ewelina; Cebrat, Marek; Szewczuk, Zbigniew

2014-10-01

Improving the sensitivity of detection and fragmentation of peptides to provide reliable sequencing of peptides is an important goal of mass spectrometric analysis. Peptides derivatized by bicyclic quaternary ammonium ionization tags: 1-azabicyclo[2.2.2]octane (ABCO) or 1,4-diazabicyclo[2.2.2]octane (DABCO), are characterized by an increased detection sensitivity in electrospray ionization mass spectrometry (ESI-MS) and longer retention times on the reverse-phase (RP) chromatography columns. The improvement of the detection limit was observed even for peptides dissolved in 10 mM NaCl. Collision-induced dissociation tandem mass spectrometry of quaternary ammonium salts derivatives of peptides showed dominant a- and b-type ions, allowing facile sequencing of peptides. The bicyclic ionization tags are stable in collision-induced dissociation experiments, and the resulted fragmentation pattern is not significantly influenced by either acidic or basic amino acid residues in the peptide sequence. Obtained results indicate the general usefulness of the bicyclic quaternary ammonium ionization tags for ESI-MS/MS sequencing of peptides. Copyright © 2014 John Wiley & Sons, Ltd.

Monoalkyl sulfates as alkylating agents in water, alkylsulfatase rate enhancements, and the “energy-rich” nature of sulfate half-esters

PubMed Central

Wolfenden, Richard; Yuan, Yang

2007-01-01

Alkyl sulfate monoesters are involved in cell signaling and structure. Alkyl sulfates are also present in many commercial detergents. Here, we show that monomethyl sulfate acts as an efficient alkylating agent in water, reacting spontaneously with oxygen nucleophiles >100-fold more rapidly than do alkylsulfonium ions, the usual methyl donors in living organisms. These reactions of methyl sulfate, which are much more rapid than its hydrolysis, are insensitive to the nature of the attacking nucleophile, with a Brønsted βnuc value of −0.01. Experiments at elevated temperatures indicate a rate constant of 2 × 10−11 s−1 for the uncatalyzed hydrolysis of methyl sulfate at 25°C (t1/2 = 1,100 y), corresponding to a rate enhancement of ≈1011-fold by a human alkylsulfatase. Equilibria of formation of methyl sulfate from methanol and sodium hydrogen sulfate indicate a group transfer potential (ΔG′pH7) of −8.9 kcal/mol for sulfate ester hydrolysis. The magnitude of that value, involving release of the strong acid HSO4−, helps to explain the need for harnessing the free energy of hydrolysis of two ATP molecules in activating sulfate for the biosynthesis of sulfate monoesters. The “energy-rich” nature of monoalkyl sulfate esters, coupled with their marked resistance to hydrolysis, renders them capable of acting as sulfating or alkylating agents under relatively mild conditions. These findings raise the possibility that, under appropriate circumstances, alkyl groups may undergo transfer from alkyl sulfate monoesters to biological target molecules. PMID:17182738

Dodecylbenzene sulfonate-coated magnetite nanoparticles as a new adsorbent for solid phase extraction-spectrophotometric determination of ultra trace amounts of ammonium in water samples.

PubMed

Eskandari, Habibollah; Shariati, Mohammad Reza

2011-10-17

A new method was proposed for the determination of ammonium based on the preconcentration with dodecylbenzene sulfonate modified magnetite nanoparticles. Ammonium was oxidized to nitrite by hypobromite and then the nitrite produced was determined spectrophotometrically, using sulfabenzamide and N-(1-naphthyl) ethylenediamine after solid phase extraction. The azo dye produced was desorbed by an appropriate small volume of sodium hydroxide prior to the absorbance measurement. The linear calibration graphs were obtained in the concentration range of 0.03-6.00 ng mL(-1) ammonium. The relative standard deviation and recovery percents were 1.0 and 99.0, respectively, for 1.0 ng mL(-1) ammonium, and the limit of detection was 3.2 ng L(-1) ammonium. The interfering effects of a large number of diverse ions on the determination of ammonium were studied. The method was applied to the determination of ammonium in various types of water resources. The results revealed a high efficiency for the recommended ammonium determination method. Copyright © 2011 Elsevier B.V. All rights reserved.

Synthesis, characterization and antibacterial properties of dihydroxy quaternary ammonium salts with long chain alkyl bromides.

PubMed

Liu, Wen-Shuai; Wang, Chun-Hua; Sun, Ju-Feng; Hou, Gui-Ge; Wang, Yu-Peng; Qu, Rong-Jun

2015-01-01

Five N-methyl-N-R-N,N-bis(2-hydroxyethyl) ammonium bromides (R = -benzyl (chloride, BNQAS), -dodecyl (C12QAS), -tetradecyl (C14QAS), -hexadecyl (C16QAS), -octadecyl (C18QAS)) were prepared based on N-methyldiethanolamine (MDEA) and halohydrocarbon. Five QAS were characterized by FTIR, NMR, and MS. BNQAS, C12QAS, C14QAS, and C16QAS were confirmed by X-ray single-crystal diffraction. Their antibacterial properties indicated good antibacterial abilities against E. coli, S. aureus, B. subtilis, especially C12QAS with the best antibacterial ability (100% to E. coli, 95.65% to S. aureus, and 91.41% to B. subtilis). In addition, C12QAS also displayed the best antifungal activities than BNQAS and C18QAS against Cytospora mandshurica, Botryosphaeria ribis, Physalospora piricola, and Glomerella cingulata with the ratio of full marks. The strategy provides a facile way to design and develop new types of antibacterial drugs for application in preventing the fruit rot, especially apple. © 2014 John Wiley & Sons A/S.

Polyimide characterization studies - Effect of pendant alkyl groups

NASA Technical Reports Server (NTRS)

Jensen, B. J.; Young, P. R.

1984-01-01

The effect on selected polyimide properties when pendant alkyl groups were attached to the polymer backbone was investigated. A series of polymers were prepared using benzophenone tetracarboxylic acid dianhydride (BTDA) and seven different p-alkyl-m,p'-diaminobenzophenone monomers. The alkyl groups varied in length from C(1) (methyl) to C(9) (nonyl). The polyimide prepared from BTDA and m,p'-diaminobenzophenone was included as a control. All polymers were characterized by various chromatographic, spectroscopic, thermal, and mechanical techniques. Increasing the length of the pendant alkyl group resulted in a systematic decrease in glass transition temperature (Tg) for vacuum cured films. A 70 C decrease in Tg to 193 C was observed for the nonyl polymer compared to the Tg for the control. A corresponding systematic increase in Tg indicative of crosslinking, was observed for air cured films. Thermogravimetric analysis revealed a slight sacrifice in thermal stability with increasing alkyl length. No improvement in film toughness was observed.

Isomeric Detergent Comparison for Membrane Protein Stability: Importance of Inter-Alkyl-Chain Distance and Alkyl Chain Length

PubMed Central

Cho, Kyung Ho; Hariharan, Parameswaran; Mortensen, Jonas S.; Du, Yang; Nielsen, Anne K.; Byrne, Bernadette; Kobilka, Brian K.; Loland, Claus J.; Guan, Lan

2017-01-01

Membrane proteins encapsulated by detergent micelles are widely used for structural study. Because of their amphipathic property, detergents have the ability to maintain protein solubility and stability in an aqueous medium. However, conventional detergents have serious limitations in their scope and utility, particularly for eukaryotic membrane proteins and membrane protein complexes. Thus, a number of new agents have been devised; some have made significant contributions to membrane protein structural studies. However, few detergent design principles are available. In this study, we prepared meta and ortho isomers of the previously reported para-substituted xylene-linked maltoside amphiphiles (XMAs), along with alkyl chain-length variation. The isomeric XMAs were assessed with three membrane proteins, and the meta isomer with a C12 alkyl chain was most effective at maintaining solubility/stability of the membrane proteins. We propose that interplay between the hydrophile–lipophile balance (HLB) and alkyl chain length is of central importance for high detergent efficacy. In addition, differences in inter-alkyl-chain distance between the isomers influence the ability of the detergents to stabilise membrane proteins. PMID:27981750

Formation of light absorbing organo-nitrogen species from evaporation of droplets containing glyoxal and ammonium sulfate.

PubMed

Lee, Alex K Y; Zhao, Ran; Li, Richard; Liggio, John; Li, Shao-Meng; Abbatt, Jonathan P D

2013-11-19

In the atmosphere, volatile organic compounds such as glyoxal can partition into aqueous droplets containing significant levels of inorganic salts. Upon droplet evaporation, both the organics and inorganic ions become highly concentrated, accelerating reactions between them. To demonstrate this process, we investigated the formation of organo-nitrogen and light absorbing materials in evaporating droplets containing glyoxal and different ammonium salts including (NH4)2SO4, NH4NO3, and NH4Cl. Our results demonstrate that evaporating glyoxal-(NH4)2SO4 droplets produce light absorbing species on a time scale of seconds, which is orders of magnitude faster than observed in bulk solutions. Using aerosol mass spectrometry, we show that particle-phase organics with high N:C ratios were formed when ammonium salts were used, and that the presence of sulfate ions promoted this chemistry. Since sulfate can also significantly enhance the Henry's law partitioning of glyoxal, our results highlight the atmospheric importance of such inorganic-organic interactions in aqueous phase aerosol chemistry.

Product ion tandem mass spectrometric differentiation of regioisomeric side-chain groups in cathinone derivatives.

PubMed

Abiedalla, Younis; DeRuiter, Jack; Clark, C Randall

2016-07-30

Precursor materials are available to prepare aminoketone drugs containing regioisomeric propyl and isopropyl side-chain groups related to the drug alpha-pyrrovalerone (Flakka) and MDPV (3,4-methylenedioxypyrrovalerone). These compounds yield equivalent regioisomeric iminium cation base peaks in electron ionization mass spectrometry (EI-MS). The propyl and isopropyl side-chain groups related to alpha-pyrrovalerone and MDPV were prepared and evaluated in EI-MS and tandem mass spectrometry (MS/MS) product ion experiments. Deuterium labeling in both the pyrrolidine and alkyl side-chain groups allowed for the confirmation of the structures for the major product ions formed from the regioisomeric EI-MS iminium cation base peaks. These iminium cation base peaks show characteristic product ion spectra which allow differentiation of the side-chain propyl and isopropyl groups in the structure. The n-propyl side chain containing iminium cation base peak (m/z 126) in the EI-MS spectrum yields a major product ion at m/z 84 while the regioisomeric m/z 126 base peak for the isopropyl side chain yields a characteristic product ion at m/z 70. Deuterium labeling in both the pyrrolidine ring and the alkyl side chain confirmed the process for the formation of these major product ions. Product ion fragmentation provides useful data for differentiation of n-propyl and isopropyl side-chain iminium cations from cathinone derivative drugs of abuse. Regioisomeric n-propyl and isopropyl iminium cations of equal mass yield characteristic product ions identifying the alkyl side-chain regioisomers in the pyrrolidine cathinone derivatives. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

A Convenient Approach to Synthesizing Peptide C-Terminal N-Alkyl Amides

PubMed Central

Fang, Wei-Jie; Yakovleva, Tatyana; Aldrich, Jane V.

2014-01-01

Peptide C-terminal N-alkyl amides have gained more attention over the past decade due to their biological properties, including improved pharmacokinetic and pharmacodynamic profiles. However, the synthesis of this type of peptide on solid phase by current available methods can be challenging. Here we report a convenient method to synthesize peptide C-terminal N-alkyl amides using the well-known Fukuyama N-alkylation reaction on a standard resin commonly used for the synthesis of peptide C-terminal primary amides, the PAL-PEG-PS (Peptide Amide Linker-polyethylene glycol-polystyrene) resin. The alkylation and oNBS deprotection were conducted under basic conditions and were therefore compatible with this acid labile resin. The alkylation reaction was very efficient on this resin with a number of different alkyl iodides or bromides, and the synthesis of model enkephalin N-alkyl amide analogs using this method gave consistently high yields and purities, demonstrating the applicability of this methodology. The synthesis of N-alkyl amides was more difficult on a Rink amide resin, especially the coupling of the first amino acid to the N-alkyl amine, resulting in lower yields for loading the first amino acid onto the resin. This method can be widely applied in the synthesis of peptide N-alkyl amides. PMID:22252422

Determination of selected quaternary ammonium compounds by liquid chromatography with mass spectrometry. Part II. Application to sediment and sludge samples in Austria.

PubMed

Martínez-Carballo, Elena; González-Barreiro, Carmen; Sitka, Andrea; Kreuzinger, Norbert; Scharf, Sigrid; Gans, Oliver

2007-03-01

Soxhlet extraction and high-performance liquid chromatography (HPLC) coupled to tandem mass spectrometry detection (MS/MS) was used for the determination of selected quaternary ammonium compounds (QACs) in solid samples. The method was applied for the determination of alkyl benzyl, dialkyl and trialkyl quaternary ammonium compounds in sediment and sludge samples in Austria. The overall method quantification limits range from 0.6 to 3 microg/kg for sediments and from 2 to 5 microg/kg for sewage sludges. Mean recoveries between 67% and 95% are achieved. In general sediments were especially contaminated by C12 chain benzalkonium chloride (BAC-C12) as well as by the long C-chain dialkyldimethylammonium chloride (DDAC-C18) with a maximum concentration of 3.6 mg/kg and 2.1mg/kg, respectively. Maxima of 27 mg/kg for DDAC-C10, 25 mg/kg for BAC-C12 and 23 mg/kg for BAC-C14 were determined for sludge samples. The sums of the 12 selected target compounds range from 22 mg/kg to 103 mg/kg in the sludge samples.

40 CFR 721.10677 - Alkyl phosphonate (generic).

Code of Federal Regulations, 2014 CFR

2014-07-01

... CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.10677 Alkyl phosphonate (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as alkyl phosphonate (PMN P-12-584...

21 CFR 556.375 - Maduramicin ammonium.

Code of Federal Regulations, 2010 CFR

2010-04-01

... residues of maduramicin ammonium in chickens as follows: (a) A tolerance for maduramicin ammonium (marker residue) in chickens is 0.38 parts per million in fat (target tissue). A tolerance refers to the... animals. (b) The safe concentrations for total maduramicin ammonium residues in uncooked edible chicken...

PREPARATION OF ALKYL PYROPHOSPHATE EXTRACTANTS

DOEpatents

Levine, C.A.; Skiens, W.E.; Moore, G.R.

1960-08-01

A process for providing superior solvent extractants for metal recovery processes is given wherein the extractant comprises an alkyl pyrophosphoric acid ester dissolved in an organic solvent diluent. Finely divided solid P/sub 2/O/ sub 5/ is slurried in an organic solvent-diluent selected from organic solvents such as kerosene, benzene, chlorobenzene, toluene, etc. An alcohol selected from the higher alcohols having 4 to 17 carbon atoms. e.g.. hexanol-1. heptanol-3, octanol-1. 2.6-dimethyl-heptanol-4, and decanol-1, is rapidly added to the P/sub 2/O/sub 5/ slurry in the amount of about 2 moles of alcohol to 1 mole of P/sub 2/ O/sub 5/. The temperature is maintained below about 110 deg C during the course of the P/sub 2/O/sub 5/-alcohol reaction. An alkyl pyrophosphate extractant compound is formed as a consequence of the reaction process. The alkyl pyrophosphate solvent-diluent extractant phase is useful in solvent extraction metal recovery processes.

Antioxidant activity of alkyl gallates and glycosyl alkyl gallates in fish oil in water emulsions: relevance of their surface active properties and of the type of emulsifier.

PubMed

González, María J; Medina, Isabel; Maldonado, Olivia S; Lucas, Ricardo; Morales, Juan C

2015-09-15

The antioxidant activity of gallic acid and a series of alkyl gallates (C4-C18) and glycosylated alkyl gallates (C4-C18) on fish oil-in-water emulsions was studied. Three types of emulsifiers, lecithin, Tween-20 and sodium dodecyl sulphate (SDS) were tested. A nonlinear behavior of the antioxidant activity of alkyl gallates when increasing alkyl chain length was observed for emulsions prepared with lecithin. Medium-size alkyl gallates (C6-C12) were the best antioxidants. In contrast, for emulsions prepared with Tween-20, the antioxidants seem to follow the polar paradox. Glucosyl alkyl gallates were shown previously to be better surfactants than alkyl gallates. Nevertheless, they exhibited a worse antioxidant capacity than their corresponding alkyl gallates, in emulsions prepared with lecithin or Tween-20, indicating the greater relevance of having three OH groups at the polar head in comparison with having improved surfactant properties but just a di-ortho phenolic structure in the antioxidant. Copyright © 2015 Elsevier Ltd. All rights reserved.

Creatinine and urea biosensors based on a novel ammonium ion-selective copper-polyaniline nano-composite.

PubMed

Zhybak, M; Beni, V; Vagin, M Y; Dempsey, E; Turner, A P F; Korpan, Y

2016-03-15

The use of a novel ammonium ion-specific copper-polyaniline nano-composite as transducer for hydrolase-based biosensors is proposed. In this work, a combination of creatinine deaminase and urease has been chosen as a model system to demonstrate the construction of urea and creatinine biosensors to illustrate the principle. Immobilisation of enzymes was shown to be a crucial step in the development of the biosensors; the use of glycerol and lactitol as stabilisers resulted in a significant improvement, especially in the case of the creatinine, of the operational stability of the biosensors (from few hours to at least 3 days). The developed biosensors exhibited high selectivity towards creatinine and urea. The sensitivity was found to be 85 ± 3.4 mAM(-1)cm(-2) for the creatinine biosensor and 112 ± 3.36 mAM(-1)cm(-2) for the urea biosensor, with apparent Michaelis-Menten constants (KM,app), obtained from the creatinine and urea calibration curves, of 0.163 mM for creatinine deaminase and 0.139 mM for urease, respectively. The biosensors responded linearly over the concentration range 1-125 µM, with a limit of detection of 0.5 µM and a response time of 15s. The performance of the biosensors in a real sample matrix, serum, was evaluated and a good correlation with standard spectrophotometric clinical laboratory techniques was found. Copyright © 2015 Elsevier B.V. All rights reserved.

49 CFR 176.415 - Permit requirements for Division 1.5, ammonium nitrates, and certain ammonium nitrate fertilizers.

Code of Federal Regulations, 2010 CFR

2010-10-01

... nitrates, and certain ammonium nitrate fertilizers. 176.415 Section 176.415 Transportation Other... Solids), Class 5 (Oxidizers and Organic Peroxides), and Division 1.5 Materials § 176.415 Permit requirements for Division 1.5, ammonium nitrates, and certain ammonium nitrate fertilizers. (a) Except as...

Toxicity of Sulfide and Ammonium to Aedes triseriatus Larvae (Diptera: Culicidae) in Water-Filled Tree Holes and Tires

PubMed Central

Walker, Edward D.

2016-01-01

Abstract Ammonium and sulfide in water of tree hole and tire habitats of Aedes triseriatus Say larvae could accumulate to toxic levels, limiting growth and production of larvae and adults. Both ions were detected in water samples taken in longitudinal series over 11 dates from 10 habitats of each type during the larval growth season, at concentrations suggestive of reducing conditions in these habitats. Ammonium was more concentrated overall in water of both habitat types, while sulfide was more concentrated in tires than in tree holes. Water of tree holes was more acidic, whereas water in tires tended to be more basic, an important difference relative to the tendency of ammonium to form the more toxic ammonia moiety under basic conditions. Oxygen saturation was low in both habitat types, indicative of hypoxic conditions such that aerobic respiration would be limited. First-and fourth-instar larvae were sensitive to ammonium and sulfide in acute dose-response assays, but LC50 values were above maximum concentrations observed under field conditions, suggesting that toxic effects of ammonium and sulfide on larvae are not acute, but could be chronic. PMID:27049027

21 CFR 582.1135 - Ammonium bicarbonate.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Ammonium bicarbonate. 582.1135 Section 582.1135 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1135 Ammonium bicarbonate. (a) Product. Ammonium bicarbonate. (b) Conditions of use. This...

21 CFR 582.1135 - Ammonium bicarbonate.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Ammonium bicarbonate. 582.1135 Section 582.1135 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1135 Ammonium bicarbonate. (a) Product. Ammonium bicarbonate. (b) Conditions of use. This...

21 CFR 582.1135 - Ammonium bicarbonate.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Ammonium bicarbonate. 582.1135 Section 582.1135 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1135 Ammonium bicarbonate. (a) Product. Ammonium bicarbonate. (b) Conditions of use. This...

21 CFR 582.1135 - Ammonium bicarbonate.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Ammonium bicarbonate. 582.1135 Section 582.1135 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1135 Ammonium bicarbonate. (a) Product. Ammonium bicarbonate. (b) Conditions of use. This...

Grafted methylenediphosphonate ion exchange resins

DOEpatents

Trochimcznk, Andrzej W.; Gatrone, Ralph C.; Alexandratos, Spiro; Horwitz, E. Philip

1998-01-27

An ion exchange resin is disclosed that is comprised of an insoluble copolymer onto which are grafted pendent groups that provide 1.0 to about 10 mmol/g dry weight phosphorous. The pendent groups have the formula ##STR1## wherein R is hydrogen, a cation or mixtures thereof; and R.sup.1 is hydrogen or an C.sub.1 -C.sub.2 alkyl group. The resin also contains zero to about 5 mmol/g dry weight of pendent aromatic sulfonate groups. Processes for making and using an ion exchange-resin are also disclosed.

Grafted methylenediphosphonate ion exchange resins

DOEpatents

Trochimcznk, Andrzej W.; Gatrone, Ralph C.; Alexandratos, Spiro; Horwitz, E. Philip

1997-01-01

An ion exchange resin is disclosed that is comprised of an insoluble copolymer onto which are grafted pendent groups that provide 1.0 to about 10 mmol/g dry weight phosphorous. The pendent groups have the formula ##STR1## wherein R is hydrogen, a cation or mixtures thereof; and R.sup.1 is hydrogen or an C.sub.1 -C.sub.2 alkyl group. The resin also contains zero to about 5 mmol/g dry weight of pendent aromatic sulfonate groups. Processes for making and using an ion exchange resin are also disclosed.

Optimalisation of magnesium ammonium phosphate precipitation and its applicability to the removal of ammonium.

PubMed

Demeestere, K; Smet, E; Van Langenhove, H; Galbacs, Z

2001-12-01

Among the physico-chemical abatement technologies, mainly acid scrubbers have been used to control NH3-emission. The disadvantage of this technique is that it yields waste water, highly concentrated in ammonia. In this report, the applicability of the magnesium ammonium phosphate (MAP) process to regenerate the liquid phase, produced by scrubbing NH3-loaded waste gases, was investigated. In the MAP process, ammonium is precipitated as magnesium ammonium phosphate, which can be used as a slow release fertilizer. The influence of a number of parameters, e.g. pH, kinetics, molar ratio NH(+)4/Mg2+/PO(3-)4 on the efficiency of the formation of MAP and on the ammonium removal efficiency was investigated. In this way, optimal conditions were determined for the precipitation reaction. Next to this, interference caused by other precipitation reactions was studied. At aqueous NH(+)4-concentrations of about 600 mg l(-1), ammonium removal efficiencies of 97% could be obtained at a molar ratio NH(+)4/Mg2+/PO(3-)4 of 1/1.5/1.5. To obtain this result, the pH was continuously adjusted to a value of 9 during the reaction. According to this study, it is obvious that the MAP-precipitation technology offers opportunities for ammonium removal from scrubbing liquids. The practical applicability of the MAP-process in waste gas treatment systems, however, should be the subject for further investigations.

Effect of the C-2 hydroxyl group on the mesomorphism of alkyl glycosides: synthesis and thermotropic behavior of alkyl 2-deoxy-D-arabino-hexopyranosides.

PubMed

Singh, Madan Kumar; Jayaraman, Narayanaswamy; Rao, D S Shankar; Prasad, S Krishna

2008-10-01

A homologous series of alkyl 2-deoxy-alpha-d-arabino-hexopyranosides and alkyl 2-deoxy-beta-d-arabino-hexopyranosides were synthesized, upon glycosylation of 1-alkanols (from C8 to C18 alkanols) with ethyl 2-deoxy-3,4,6-tri-O-acetyl-1-thio-d-arabino-hexopyranoside, followed by a deprotection. The thermotropic behavior of these new types of alkyl glycosides was investigated. It was observed that the beta-anomers of these alkyl glycosides, bearing nonyl to tetradecyl alkyl chain are mesomorphic, exhibiting monotropic smectic A phase. In contrast, the alpha-anomers are all non-mesomorphic. An effort to identify the liquid crystalline behavior of binary mixtures of the alpha- and beta-anomers was undertaken and it was found that mixtures containing equimolar amounts of the anomers exhibited mesomorphic behavior. A fine balance of the hydrophilic and hydrophobic components within the molecule is also found to be important for the alkyl 2-deoxy glycosides to form the mesophase.

Direct N-alkylation of unprotected amino acids with alcohols

PubMed Central

Yan, Tao; Feringa, Ben L.; Barta, Katalin

2017-01-01

N-alkyl amino acids find widespread application as highly valuable, renewable building blocks. However, traditional synthesis methodologies to obtain these suffer from serious limitations, providing a major challenge to develop sustainable alternatives. We report the first powerful catalytic strategy for the direct N-alkylation of unprotected α-amino acids with alcohols. This method is highly selective, produces water as the only side product leading to a simple purification procedure, and a variety of α-amino acids are mono- or di-N-alkylated, in most cases with excellent retention of optical purity. The hydrophobicity of the products is tunable, and even simple peptides are selectively alkylated. An iron-catalyzed route to mono-N-alkyl amino acids using renewable fatty alcohols is also described that represents an ideal green transformation for obtaining fully bio-based surfactants. PMID:29226249

21 CFR 582.1143 - Ammonium sulfate.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Ammonium sulfate. 582.1143 Section 582.1143 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1143 Ammonium sulfate. (a) Product. Ammonium sulfate. (b) Conditions of use. This substance...

21 CFR 582.1143 - Ammonium sulfate.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Ammonium sulfate. 582.1143 Section 582.1143 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1143 Ammonium sulfate. (a) Product. Ammonium sulfate. (b) Conditions of use. This substance...

21 CFR 582.1143 - Ammonium sulfate.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Ammonium sulfate. 582.1143 Section 582.1143 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1143 Ammonium sulfate. (a) Product. Ammonium sulfate. (b) Conditions of use. This substance...

21 CFR 582.1143 - Ammonium sulfate.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Ammonium sulfate. 582.1143 Section 582.1143 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1143 Ammonium sulfate. (a) Product. Ammonium sulfate. (b) Conditions of use. This substance...

Preparation of highly ordered cubic NaA zeolite from halloysite mineral for adsorption of ammonium ions.

PubMed

Zhao, Yafei; Zhang, Bing; Zhang, Xiang; Wang, Jinhua; Liu, Jindun; Chen, Rongfeng

2010-06-15

Well-ordered cubic NaA zeolite was first synthesized using natural halloysite mineral with nanotubular structure as source material by hydro-thermal method. SEM and HRTEM images indicate that the synthesized NaA zeolite is cubic-shaped crystal with planar surface, well-defined edges and symmetrical and uniform pore channels. The adsorption behavior of ammonium ions (NH(4)(+)) from aqueous solution onto NaA zeolite was investigated as a function of parameters such as equilibrium time, pH, initial NH(4)(+) concentration, temperature and competitive cations. The Langmuir and Freundlich adsorption models were applied to describe the equilibrium isotherms. A maximum adsorption capacity of 44.3 mg g(-1) of NH(4)(+) was achieved. The regeneration and reusable ability of this adsorbent was evaluated, and the results indicated that the recovered adsorbent could be used again for NH(4)(+) removal with nearly constant adsorption capacity. Thermodynamic parameters such as change in free energy (DeltaG(0)), enthalpy (DeltaH(0)) and entropy (DeltaS(0)) were also determined, which indicated that the adsorption was a spontaneous and exothermic process at ambient conditions. Compared with other adsorbents, the as-synthesized NaA zeolite displays a faster adsorption rate and higher adsorption capacity, which implies potential application for removing NH(4)(+) pollutants from wastewaters. Copyright 2010 Elsevier B.V. All rights reserved.

Isomeric Detergent Comparison for Membrane Protein Stability: Importance of Inter-Alkyl-Chain Distance and Alkyl Chain Length.

PubMed

Cho, Kyung Ho; Hariharan, Parameswaran; Mortensen, Jonas S; Du, Yang; Nielsen, Anne K; Byrne, Bernadette; Kobilka, Brian K; Loland, Claus J; Guan, Lan; Chae, Pil Seok

2016-12-14

Membrane proteins encapsulated by detergent micelles are widely used for structural study. Because of their amphipathic property, detergents have the ability to maintain protein solubility and stability in an aqueous medium. However, conventional detergents have serious limitations in their scope and utility, particularly for eukaryotic membrane proteins and membrane protein complexes. Thus, a number of new agents have been devised; some have made significant contributions to membrane protein structural studies. However, few detergent design principles are available. In this study, we prepared meta and ortho isomers of the previously reported para-substituted xylene-linked maltoside amphiphiles (XMAs), along with alkyl chain-length variation. The isomeric XMAs were assessed with three membrane proteins, and the meta isomer with a C 12 alkyl chain was most effective at maintaining solubility/stability of the membrane proteins. We propose that interplay between the hydrophile-lipophile balance (HLB) and alkyl chain length is of central importance for high detergent efficacy. In addition, differences in inter-alkyl-chain distance between the isomers influence the ability of the detergents to stabilise membrane proteins. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Salvage of failed protein targets by reductive alkylation.

PubMed

Tan, Kemin; Kim, Youngchang; Hatzos-Skintges, Catherine; Chang, Changsoo; Cuff, Marianne; Chhor, Gekleng; Osipiuk, Jerzy; Michalska, Karolina; Nocek, Boguslaw; An, Hao; Babnigg, Gyorgy; Bigelow, Lance; Joachimiak, Grazyna; Li, Hui; Mack, Jamey; Makowska-Grzyska, Magdalena; Maltseva, Natalia; Mulligan, Rory; Tesar, Christine; Zhou, Min; Joachimiak, Andrzej

2014-01-01

The growth of diffraction-quality single crystals is of primary importance in protein X-ray crystallography. Chemical modification of proteins can alter their surface properties and crystallization behavior. The Midwest Center for Structural Genomics (MCSG) has previously reported how reductive methylation of lysine residues in proteins can improve crystallization of unique proteins that initially failed to produce diffraction-quality crystals. Recently, this approach has been expanded to include ethylation and isopropylation in the MCSG protein crystallization pipeline. Applying standard methods, 180 unique proteins were alkylated and screened using standard crystallization procedures. Crystal structures of 12 new proteins were determined, including the first ethylated and the first isopropylated protein structures. In a few cases, the structures of native and methylated or ethylated states were obtained and the impact of reductive alkylation of lysine residues was assessed. Reductive methylation tends to be more efficient and produces the most alkylated protein structures. Structures of methylated proteins typically have higher resolution limits. A number of well-ordered alkylated lysine residues have been identified, which make both intermolecular and intramolecular contacts. The previous report is updated and complemented with the following new data; a description of a detailed alkylation protocol with results, structural features, and roles of alkylated lysine residues in protein crystals. These contribute to improved crystallization properties of some proteins.

Salvage of Failed Protein Targets by Reductive Alkylation

PubMed Central

Tan, Kemin; Kim, Youngchang; Hatzos-Skintges, Catherine; Chang, Changsoo; Cuff, Marianne; Chhor, Gekleng; Osipiuk, Jerzy; Michalska, Karolina; Nocek, Boguslaw; An, Hao; Babnigg, Gyorgy; Bigelow, Lance; Joachimiak, Grazyna; Li, Hui; Mack, Jamey; Makowska-Grzyska, Magdalena; Maltseva, Natalia; Mulligan, Rory; Tesar, Christine; Zhou, Min; Joachimiak, Andrzej

2014-01-01

The growth of diffraction-quality single crystals is of primary importance in protein X-ray crystallography. Chemical modification of proteins can alter their surface properties and crystallization behavior. The Midwest Center for Structural Genomics (MCSG) has previously reported how reductive methylation of lysine residues in proteins can improve crystallization of unique proteins that initially failed to produce diffraction-quality crystals. Recently, this approach has been expanded to include ethylation and isopropylation in the MCSG protein crystallization pipeline. Applying standard methods, 180 unique proteins were alkylated and screened using standard crystallization procedures. Crystal structures of 12 new proteins were determined, including the first ethylated and the first isopropylated protein structures. In a few cases, the structures of native and methylated or ethylated states were obtained and the impact of reductive alkylation of lysine residues was assessed. Reductive methylation tends to be more efficient and produces the most alkylated protein structures. Structures of methylated proteins typically have higher resolution limits. A number of well-ordered alkylated lysine residues have been identified, which make both intermolecular and intramolecular contacts. The previous report is updated and complemented with the following new data; a description of a detailed alkylation protocol with results, structural features, and roles of alkylated lysine residues in protein crystals. These contribute to improved crystallization properties of some proteins. PMID:24590719

Ammonium removal from high-strength aqueous solutions by Australian zeolite.

PubMed

Wijesinghe, D Thushari N; Dassanayake, Kithsiri B; Sommer, Sven G; Jayasinghe, Guttila Y; J Scales, Peter; Chen, Deli

2016-07-02

Removal of ammonium nitrogen (NH4(+)-N) particularly from sources which are highly rich in nitrogen is important for addressing environmental pollution. Zeolites, aluminosilicate minerals, are commonly used as commercial adsorbents and ion-exchange medium in number of commercial applications due to its high adsorption capacity of ammonium (NH4(+)). However, detailed investigations on NH4(+) adsorption and ion exchange capacities of Australian natural zeolites are rare, particularly under higher NH4(+) concentrations in the medium. Therefore, this study was conducted to determine NH4(+) adsorption characteristics of Australian natural zeolites at high NH4(+) concentrations with and without other chemical compounds in an aqueous solution. Results showed that initial NH4(+) concentration, temperature, reaction time, and pH of the solution had significant effects on NH4(+) adsorption capacity of zeolite. Increased retention time and temperature generally had a positive impact on adsorption. Freundlich model fitted well with adsorption process of Australian natural zeolites; however, Langmuir model had best fitted for the adsorption process of sodium (Na(+)) treated zeolites. NaCl treatment increased the NH4(+) adsorption capacity of Australian zeolites by 25% at 1000 mg-N, NH4(+) solution. The maximum adsorption capacity of both natural Australian zeolites and Na(+) treated zeolites were estimated as 9.48 and 11.83 mg-N/g, respectively, which is lower than many zeolites from other sources. Compared to the NH4(+) only medium, presence of other competitive ions and acetic acid in the medium (resembling composition in digested swine manure slurries) reduced NH4(+) removal of natural and Na(+) treated zeolites by 44% and 57%, respectively. This suggests detailed investigations are required to determine practically achievable NH4(+) -N removal potential of zeolites for applications in complex mediums such as animal manure slurries.

Analysis of multiple quaternary ammonium compounds in the brain using tandem capillary column separation and high resolution mass spectrometric detection.

PubMed

Falasca, Sara; Petruzziello, Filomena; Kretz, Robert; Rainer, Gregor; Zhang, Xiaozhe

2012-06-08

Endogenous quaternary ammonium compounds are involved in various physiological processes in the central nervous system. In the present study, eleven quaternary ammonium compounds, including acetylcholine, choline, carnitine, acetylcarnitine and seven other acylcarnitines of low polarity, were analyzed from brain extracts using a two dimension capillary liquid chromatography-Fourier transform mass spectrometry method. To deal with their large difference in hydrophobicities, tandem coupling between reversed phase and hydrophilic interaction chromatography columns was used to separate all the targeted quaternary ammonium compounds. Using high accuracy mass spectrometry in selected ion monitoring mode, all the compounds could be detected from each brain sample with high selectivity. The developed method was applied for the relative quantification of these quaternary ammonium compounds in three different brain regions of tree shrews: prefrontal cortex, striatum, and hippocampus. The comparative analysis showed that quaternary ammonium compounds were differentially distributed across the three brain areas. The analytical method proved to be highly sensitive and reliable for simultaneous determination of all the targeted analytes from brain samples. Copyright © 2012 Elsevier B.V. All rights reserved.

Balancing repair and tolerance of DNA damage caused by alkylating agents.

PubMed

Fu, Dragony; Calvo, Jennifer A; Samson, Leona D

2012-01-12

Alkylating agents constitute a major class of frontline chemotherapeutic drugs that inflict cytotoxic DNA damage as their main mode of action, in addition to collateral mutagenic damage. Numerous cellular pathways, including direct DNA damage reversal, base excision repair (BER) and mismatch repair (MMR), respond to alkylation damage to defend against alkylation-induced cell death or mutation. However, maintaining a proper balance of activity both within and between these pathways is crucial for a favourable response of an organism to alkylating agents. Furthermore, the response of an individual to alkylating agents can vary considerably from tissue to tissue and from person to person, pointing to genetic and epigenetic mechanisms that modulate alkylating agent toxicity.

Asymmetric synthesis of α-amino acids via homologation of Ni(II) complexes of glycine Schiff bases; Part 1: alkyl halide alkylations.

PubMed

Sorochinsky, Alexander E; Aceña, José Luis; Moriwaki, Hiroki; Sato, Tatsunori; Soloshonok, Vadim A

2013-10-01

Alkylations of chiral or achiral Ni(II) complexes of glycine Schiff bases constitute a landmark in the development of practical methodology for asymmetric synthesis of α-amino acids. Straightforward, easy preparation as well as high reactivity of these Ni(II) complexes render them ready available and inexpensive glycine equivalents for preparing a wide variety of α-amino acids, in particular on a relatively large scale. In the case of Ni(II) complexes containing benzylproline moiety as a chiral auxiliary, their alkylation proceeds with high thermodynamically controlled diastereoselectivity. Similar type of Ni(II) complexes derived from alanine can also be used for alkylation providing convenient access to quaternary, α,α-disubstituted α-amino acids. Achiral type of Ni(II) complexes can be prepared from picolinic acid or via recently developed modular approach using simple secondary or primary amines. These Ni(II) complexes can be easily mono/bis-alkylated under homogeneous or phase-transfer catalysis conditions. Origin of diastereo-/enantioselectivity in the alkylations reactions, aspects of practicality, generality and limitations of this methodology is critically discussed.

Infrared spectroscopic study of SO42- ions included in M‧2M‧‧(SeO4)2ṡ6H2O (Me‧ = K, NH4+; M‧‧ = Mg, Co, Ni, Cu, Zn) and NH4+ ions included in K2M(XO4)2ṡ6H2O (X = S, Se; M‧‧ = Mg, Co, Ni, Cu, Zn)

NASA Astrophysics Data System (ADS)

Marinova, D.; Karadjova, V.; Stoilova, D.

2015-01-01

Infrared spectra of Tutton compounds, M‧2M‧‧(XO4)2ṡ6H2O (M‧ = K, NH4+; M‧‧ = Mg, Co, Ni, Cu, Zn; X = S, Se), as well as those of SO42- guest ions included in selenate host lattices and of NH4+ guest ions included in potassium host lattices are presented and discussed in the regions of ν3 and ν1 of SO42- guest ions, ν4 of NH4+ guest ions and water librations. The SO42- guest ions matrix-isolated in selenate matrices (approximately 2 mol%) exhibit three bands corresponding to ν3 and one band corresponding to ν1 in good agreement with the low site symmetry C1 of the host selenate ions. When the larger SeO42- ions are replaced by the smaller SO42- ions the mean values of the asymmetric stretching modes νbar3 of the included SO42- ions are slightly shifted to lower frequencies as compared to those of the same ions in the neat sulfate compounds due to the smaller repulsion potential of the selenate matrices (larger unit-cell volumes of the selenates). It has been established that the extent of energetic distortion of the sulfate ions matrix-isolated in the ammonium selenates as deduced from the values of Δν3 and Δν3/νc is stronger than that of the same ions matrix-isolated in the potassium selenates due to the formation of hydrogen bonds between the SO42- guest ions with both the water molecules in the host compounds and the NH4+ host ions (for example, Δν3 of the sulfate guest ions have values of 30 and 51 cm-1 in the nickel potassium and ammonium compounds, and 33 and 49 cm-1 in the zinc potassium and ammonium compounds, respectively). The infrared spectra of ammonium doped potassium sulfate matrices show three bands corresponding to Δν4 of the included ammonium ions in agreement with the low site symmetry C1 of the host potassium ions. However, the inclusion of ammonium ions in selenate matrices (with exception of the magnesium compound) leads to the appearance of four bands in the region of ν4. At that stage of our knowledge we assume

21 CFR 184.1143 - Ammonium sulfate.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Ammonium sulfate. 184.1143 Section 184.1143 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) DIRECT... GRAS § 184.1143 Ammonium sulfate. (a) Ammonium sulfate ((NH4)2SO4, CAS Reg. No. 7783-20-2) occurs...

21 CFR 184.1143 - Ammonium sulfate.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Ammonium sulfate. 184.1143 Section 184.1143 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR... Specific Substances Affirmed as GRAS § 184.1143 Ammonium sulfate. (a) Ammonium sulfate ((NH4)2SO4, CAS Reg...

21 CFR 184.1143 - Ammonium sulfate.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Ammonium sulfate. 184.1143 Section 184.1143 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR... Specific Substances Affirmed as GRAS § 184.1143 Ammonium sulfate. (a) Ammonium sulfate ((NH4)2SO4, CAS Reg...

The adsorption of alkyl-dimethyl-benzyl-ammonium chloride onto cotton nonwoven hydroentangled substrates at the solid-liquid interface is minimized by additive chemistries

USDA-ARS?s Scientific Manuscript database

Quaternary ammonium compounds, commonly referred to as quats, are cationic surfactants widely used as the active biocide ingredient for disposable disinfecting wipes. The cationic nature of quats results in a strong ionic interaction and adsorption onto wipes materials that have an anionic surface ...

Microbially mediated clinoptilolite regeneration in a multifunctional permeable reactive barrier used to remove ammonium from landfill leachate contamination: laboratory column evaluation.

PubMed

Nooten, Thomas Van; Diels, Ludo; Bastiaens, Leen

2010-05-01

This study focuses on multifunctional permeable reactive barrier (multibarrier) technology, combining microbial degradation and abiotic ion exchange processes for removal of ammonium from landfill leachate contamination. The sequential multibarrier concept relies on the use of a clinoptilolite-filled buffer compartment to ensure a robust ammonium removal in case of temporary insufficient microbial activities. An innovative strategy was developed to allow in situ clinoptilolite regeneration. Laboratory-scale clinoptilolite-filled columns were first saturated with ammonium, using real landfill leachate as well as synthetic leachates as feed media. Other inorganic metal cations, typically present in landfill leachate, had a detrimental influence on the ammonium removal capacity by competing for clinoptilolite exchange sites. On the other hand, the metals had a highly favorable impact on regeneration of the saturated material. Feeding the columns with leachate deprived from ammonium (e.g., by microbial nitrification in an upgradient compartment), resulted in a complete release of the previously sorbed ammonium from the clinoptilolite, due to exchange with metal cations present in the leachate. The released ammonium is then available for microbial consumption in a downgradient compartment. The regeneration process resulted in a slightly increased ammonium exchange capacity afterward. The described strategy throws a new light on sustainable use of sorption materials for in situ groundwater remediation, by avoiding the need for material replacement and the use of external chemical regenerants.

Gas Chromatography/Atmospheric Pressure Chemical Ionization-Fourier Transform Ion Cyclotron Resonance Mass Spectrometry of Pyrolysis Oil from German Brown Coal

PubMed Central

Zuber, Jan; Kroll, Marius M.; Rathsack, Philipp; Otto, Matthias

2016-01-01

Pyrolysis oil from the slow pyrolysis of German brown coal from Schöningen, obtained at a temperature of 500°C, was separated and analyzed using hyphenation of gas chromatography with an atmospheric pressure chemical ionization source operated in negative ion mode and Fourier transform ion cyclotron resonance mass spectrometry (GC-APCI-FT-ICR-MS). Development of this ultrahigh-resolving analysis method is described, that is, optimization of specific GC and APCI parameters and performed data processing. The advantages of GC-APCI-FT-ICR-MS hyphenation, for example, soft ionization, ultrahigh-resolving detection, and most important isomer separation, were demonstrated for the sample liquid. For instance, it was possible to separate and identify nine different propylphenol, ethylmethylphenol, and trimethylphenol isomers. Furthermore, homologous series of different acids, for example, alkyl and alkylene carboxylic acids, were verified, as well as homologous series of alkyl phenols, alkyl dihydroxy benzenes, and alkoxy alkyl phenols. PMID:27066076

40 CFR 721.10548 - Mixed alkyl phosphate esters alkoxylated (generic).

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Mixed alkyl phosphate esters... Specific Chemical Substances § 721.10548 Mixed alkyl phosphate esters alkoxylated (generic). (a) Chemical... as mixed alkyl phosphate esters alkoxylated (PMN P-04-624) is subject to reporting under this section...

40 CFR 721.10548 - Mixed alkyl phosphate esters alkoxylated (generic).

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Mixed alkyl phosphate esters... Specific Chemical Substances § 721.10548 Mixed alkyl phosphate esters alkoxylated (generic). (a) Chemical... as mixed alkyl phosphate esters alkoxylated (PMN P-04-624) is subject to reporting under this section...

Structural basis for the enhanced stability of protein model compounds and peptide backbone unit in ammonium ionic liquids.

PubMed

Vasantha, T; Attri, Pankaj; Venkatesu, Pannuru; Devi, R S Rama

2012-10-04

Protein folding/unfolding is a fascinating study in the presence of cosolvents, which protect/disrupt the native structure of protein, respectively. The structure and stability of proteins and their functional groups may be modulated by the addition of cosolvents. Ionic liquids (ILs) are finding a vast array of applications as novel cosolvents for a wide variety of biochemical processes that include protein folding. Here, the systematic and quantitative apparent transfer free energies (ΔG'(tr)) of protein model compounds from water to ILs through solubility measurements as a function of IL concentration at 25 °C have been exploited to quantify and interpret biomolecular interactions between model compounds of glycine peptides (GPs) with ammonium based ILs. The investigated aqueous systems consist of zwitterionic glycine peptides: glycine (Gly), diglycine (Gly(2)), triglycine (Gly(3)), tetraglycine (Gly(4)), and cyclic glycylglycine (c(GG)) in the presence of six ILs such as diethylammonium acetate (DEAA), diethylammonium hydrogen sulfate (DEAS), triethylammonium acetate (TEAA), triethylammonium hydrogen sulfate (TEAS), triethylammonium dihydrogen phosphate (TEAP), and trimethylammonium acetate (TMAA). We have observed positive values of ΔG'(tr) for GPs from water to ILs, indicating that interactions between ILs and GPs are unfavorable, which leads to stabilization of the structure of model protein compounds. Moreover, our experimental data ΔG'(tr) is used to obtain transfer free energies (Δg'(tr)) of the peptide backbone unit (or glycyl unit) (-CH(2)C═ONH-), which is the most numerous group in globular proteins, from water to IL solutions. To obtain the mechanism events of the ILs' role in enhancing the stability of the model compounds, we have further obtained m-values for GPs from solubility limits. These results explicitly elucidate that all alkyl ammonium ILs act as stabilizers for model compounds through the exclusion of ILs from model compounds of

Evolution of Electrogenic Ammonium Transporters (AMTs)

DOE PAGES

McDonald, Tami R.; Ward, John M.

2016-03-31

The ammonium transporter gene family consists of three main clades, AMT, MEP, and Rh. The evolutionary history of the AMT/MEP/Rh gene family is characterized by multiple horizontal gene transfer events, gene family expansion and contraction, and gene loss; thus the gene tree for this family of transporters is unlike the organismal tree. The genomes of angiosperms contain genes for both electrogenic and electroneutral ammonium transporters, but it is not clear how far back in the land plant lineage electrogenic ammonium transporters occur. Here, we place Marchantia polymorpha ammonium transporters in the AMT/MEP/Rh phylogeny and we show that AMTs from themore » liverwort M. polymorpha are electrogenic. This information suggests that electrogenic ammonium transport evolved at least as early as the divergence of bryophytes in the land plant lineage.« less

Evolution of Electrogenic Ammonium Transporters (AMTs)

DOE Office of Scientific and Technical Information (OSTI.GOV)

McDonald, Tami R.; Ward, John M.

The ammonium transporter gene family consists of three main clades, AMT, MEP, and Rh. The evolutionary history of the AMT/MEP/Rh gene family is characterized by multiple horizontal gene transfer events, gene family expansion and contraction, and gene loss; thus the gene tree for this family of transporters is unlike the organismal tree. The genomes of angiosperms contain genes for both electrogenic and electroneutral ammonium transporters, but it is not clear how far back in the land plant lineage electrogenic ammonium transporters occur. Here, we place Marchantia polymorpha ammonium transporters in the AMT/MEP/Rh phylogeny and we show that AMTs from themore » liverwort M. polymorpha are electrogenic. This information suggests that electrogenic ammonium transport evolved at least as early as the divergence of bryophytes in the land plant lineage.« less

40 CFR 721.5380 - Mixed alkyl phenolic novolak resin (generic).

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Mixed alkyl phenolic novolak resin... Specific Chemical Substances § 721.5380 Mixed alkyl phenolic novolak resin (generic). (a) Chemical... as mixed alkyl phenolic novolak resin (PMN P-98-718) is subject to reporting under this section for...

40 CFR 721.5380 - Mixed alkyl phenolic novolak resin (generic).

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Mixed alkyl phenolic novolak resin... Specific Chemical Substances § 721.5380 Mixed alkyl phenolic novolak resin (generic). (a) Chemical... as mixed alkyl phenolic novolak resin (PMN P-98-718) is subject to reporting under this section for...

40 CFR 721.5380 - Mixed alkyl phenolic novolak resin (generic).

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Mixed alkyl phenolic novolak resin... Specific Chemical Substances § 721.5380 Mixed alkyl phenolic novolak resin (generic). (a) Chemical... as mixed alkyl phenolic novolak resin (PMN P-98-718) is subject to reporting under this section for...

40 CFR 721.5380 - Mixed alkyl phenolic novolak resin (generic).

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Mixed alkyl phenolic novolak resin... Specific Chemical Substances § 721.5380 Mixed alkyl phenolic novolak resin (generic). (a) Chemical... as mixed alkyl phenolic novolak resin (PMN P-98-718) is subject to reporting under this section for...

40 CFR 721.5380 - Mixed alkyl phenolic novolak resin (generic).

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Mixed alkyl phenolic novolak resin... Specific Chemical Substances § 721.5380 Mixed alkyl phenolic novolak resin (generic). (a) Chemical... as mixed alkyl phenolic novolak resin (PMN P-98-718) is subject to reporting under this section for...

40 CFR 721.10493 - Tris-alkyl-alkoxy melamine polymer (generic).

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Tris-alkyl-alkoxy melamine polymer... Specific Chemical Substances § 721.10493 Tris-alkyl-alkoxy melamine polymer (generic). (a) Chemical... as tris-alkyl-alkoxy melamine polymer (PMN P-05-417) is subject to reporting under this section for...

40 CFR 721.10493 - Tris-alkyl-alkoxy melamine polymer (generic).

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Tris-alkyl-alkoxy melamine polymer... Specific Chemical Substances § 721.10493 Tris-alkyl-alkoxy melamine polymer (generic). (a) Chemical... as tris-alkyl-alkoxy melamine polymer (PMN P-05-417) is subject to reporting under this section for...

An influence of structural changes in ammonium cations on ecotoxicity of 2,2'-thiodiacetate mono and bis-salts.

PubMed

Biczak, R; Turek, M; Pawłowska, B; Różycka-Sokołowska, E; Marciniak, B; Deska, M; Krupa, P; Jatulewicz, I; Skalik, J; Bałczewski, P

2018-07-15

2,2'-Thiodiacetates with their excellent complexing properties may be used as metal extraction agents, fluorescent and superparamagnetic materials, antibacterial and anticancer medical agents, however there are no data concerning the environmental impact of 2,2'-thiodiacetates derivatives and data definying the potential hazard connected with their use. This study describes the ecotoxicity assessment of seven 2,2'-thiodiacetates with non-metallic, alkyl and aryl ammonium cations, which were obtained in an environmentally friendly, solvent-free syntheses. The ecotoxicity of these water soluble compounds was tested in aquatic and benthic environments using luminescent marine bacteria Vibrio fischeri (Microtox ® test) and the crustaceans Heterocypris incongruens (Ostracodtoxkit F™), respectively. The antimicrobial and antifungal activity against Trichoderma viridis, Aspergillus niger, Rhizoctonia solani and Escherichia coli was also investigated. The results showed how structural changes within ammonium cations themselves influence ecotoxicity: the QASs with alkylammonium cations exhibited a similar, rather low toxicity both to Vibrio fischeri and Heterocypris incongruens, and they would not pose a risk to these organisms in case of leakage. Higher toxicity was observed in case of two isoquinolinium salts, however it was rather associated with the heteroaromatic cation, than with the 2,2'-thiodiacetate anion. Copyright © 2018 Elsevier Inc. All rights reserved.

Selective alkylation of T–T mismatched DNA using vinyldiaminotriazine–acridine conjugate

PubMed Central

Onizuka, Kazumitsu; Usami, Akira; Yamaoki, Yudai; Kobayashi, Tomohito; Hazemi, Madoka E; Chikuni, Tomoko; Sato, Norihiro; Sasaki, Kaname; Katahira, Masato

2018-01-01

Abstract The alkylation of the specific higher-order nucleic acid structures is of great significance in order to control its function and gene expression. In this report, we have described the T–T mismatch selective alkylation with a vinyldiaminotriazine (VDAT)–acridine conjugate. The alkylation selectively proceeded at the N3 position of thymidine on the T–T mismatch. Interestingly, the alkylated thymidine induced base flipping of the complementary base in the duplex. In a model experiment for the alkylation of the CTG repeats DNA which causes myotonic dystrophy type 1 (DM1), the observed reaction rate for one alkylation increased in proportion to the number of T–T mismatches. In addition, we showed that primer extension reactions with DNA polymerase and transcription with RNA polymerase were stopped by the alkylation. The alkylation of the repeat DNA will efficiently work for the inhibition of replication and transcription reactions. These functions of the VDAT–acridine conjugate would be useful as a new biochemical tool for the study of CTG repeats and may provide a new strategy for the molecular therapy of DM1. PMID:29309639

Alkyl chitosan film-high strength, functional biomaterials.

PubMed

Lu, Li; Xing, Cao; Xin, Shen; Shitao, Yu; Feng, Su; Shiwei, Liu; Fusheng, Liu; Congxia, Xie

2017-11-01

Biofilm with strong tensile strength is a topic item in the area of tissue engineering, medicine engineering, and so forth. Here we introduced an alkyl chitosan film with strong tensile strength and its possibility for an absorbable anticoagulation material in vivo was tested in the series of blood test, such as dynamic coagulation time, plasma recalcification time and hemolysis. Alkyl chitosan film was a better biomaterial than traditional chitosan film in the anticoagulation, tissue compatibility and cell compatibility. The unique trait of alkyl chitosan film may be for its greater contact angle and hydrophobicity ability to reduce the adsorption capacity for the blood component and the activity of fibrinolytic enzymes, enhance the antibacterial capacity than chitosan film. Moreover, none of chitosan film or butyl chitosan film exhibited quick inflammation or other disadvantage and degraded quickly by implanted test. Therefore, Alkyl chitosan film is of prospective properties as an implantable, absorbable agent for tissue heals, and this material need further research. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 3034-3041, 2017. © 2017 Wiley Periodicals, Inc.

Ammonium nitrate explosive systems

DOEpatents

Stinecipher, Mary M.; Coburn, Michael D.

1981-01-01

Novel explosives which comprise mixtures of ammonium nitrate and an ammonium salt of a nitroazole in desired ratios are disclosed. A preferred nitroazole is 3,5-dinitro-1,2,4-triazole. The explosive and physical properties of these explosives may readily be varied by the addition of other explosives and oxidizers. Certain of these mixtures have been found to act as ideal explosives.

40 CFR 721.2565 - Alkylated sulfonated diphenyl oxide, alkali and amine salts.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Alkylated sulfonated diphenyl oxide... New Uses for Specific Chemical Substances § 721.2565 Alkylated sulfonated diphenyl oxide, alkali and... substances identified as alkylated sulfonated diphenyl oxide, alkali salt (PMN P-93-352) and alkylated...

40 CFR 721.2565 - Alkylated sulfonated diphenyl oxide, alkali and amine salts.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Alkylated sulfonated diphenyl oxide... New Uses for Specific Chemical Substances § 721.2565 Alkylated sulfonated diphenyl oxide, alkali and... substances identified as alkylated sulfonated diphenyl oxide, alkali salt (PMN P-93-352) and alkylated...

Detection and identification of alkylating agents by using a bioinspired "chemical nose".

PubMed

Hertzog-Ronen, Carmit; Borzin, Elena; Gerchikov, Yulia; Tessler, Nir; Eichen, Yoav

2009-10-12

Alkylating agents are simple and reactive molecules that are commonly used in many and diverse fields such as organic synthesis, medicine, and agriculture. Some highly reactive alkylating species are also being used as blister chemical-warfare agents. The detection and identification of alkylating agents is not a trivial issue because of their high reactivity and simple structure. Herein, we report on a new multispot luminescence-based approach to the detection and identification of alkylating agents. In order to demonstrate the potential of the approach, seven pi-conjugated oligomers and polymers bearing nucleophilic pyridine groups, 1-7, were adsorbed onto a solid support and exposed to vapors of alkylators 8-15. The alkylation-induced color-shift patterns of the seven-spot array allow clear discrimination of the different alkylators. The spots are sensitive to minute concentrations of alkylators and, because the detection is based on the formation of new covalent bonds, these spots saturate at about 50 ppb.

Electrochemically and Bioelectrochemically Induced Ammonium Recovery

PubMed Central

Gildemyn, Sylvia; Luther, Amanda K.; Andersen, Stephen J.; Desloover, Joachim; Rabaey, Korneel

2015-01-01

Streams such as urine and manure can contain high levels of ammonium, which could be recovered for reuse in agriculture or chemistry. The extraction of ammonium from an ammonium-rich stream is demonstrated using an electrochemical and a bioelectrochemical system. Both systems are controlled by a potentiostat to either fix the current (for the electrochemical cell) or fix the potential of the working electrode (for the bioelectrochemical cell). In the bioelectrochemical cell, electroactive bacteria catalyze the anodic reaction, whereas in the electrochemical cell the potentiostat applies a higher voltage to produce a current. The current and consequent restoration of the charge balance across the cell allow the transport of cations, such as ammonium, across a cation exchange membrane from the anolyte to the catholyte. The high pH of the catholyte leads to formation of ammonia, which can be stripped from the medium and captured in an acid solution, thus enabling the recovery of a valuable nutrient. The flux of ammonium across the membrane is characterized at different anolyte ammonium concentrations and currents for both the abiotic and biotic reactor systems. Both systems are compared based on current and removal efficiencies for ammonium, as well as the energy input required to drive ammonium transfer across the cation exchange membrane. Finally, a comparative analysis considering key aspects such as reliability, electrode cost, and rate is made. This video article and protocol provide the necessary information to conduct electrochemical and bioelectrochemical ammonia recovery experiments. The reactor setup for the two cases is explained, as well as the reactor operation. We elaborate on data analysis for both reactor types and on the advantages and disadvantages of bioelectrochemical and electrochemical systems. PMID:25651406

Electrochemically and bioelectrochemically induced ammonium recovery.

PubMed

Gildemyn, Sylvia; Luther, Amanda K; Andersen, Stephen J; Desloover, Joachim; Rabaey, Korneel

2015-01-22

Streams such as urine and manure can contain high levels of ammonium, which could be recovered for reuse in agriculture or chemistry. The extraction of ammonium from an ammonium-rich stream is demonstrated using an electrochemical and a bioelectrochemical system. Both systems are controlled by a potentiostat to either fix the current (for the electrochemical cell) or fix the potential of the working electrode (for the bioelectrochemical cell). In the bioelectrochemical cell, electroactive bacteria catalyze the anodic reaction, whereas in the electrochemical cell the potentiostat applies a higher voltage to produce a current. The current and consequent restoration of the charge balance across the cell allow the transport of cations, such as ammonium, across a cation exchange membrane from the anolyte to the catholyte. The high pH of the catholyte leads to formation of ammonia, which can be stripped from the medium and captured in an acid solution, thus enabling the recovery of a valuable nutrient. The flux of ammonium across the membrane is characterized at different anolyte ammonium concentrations and currents for both the abiotic and biotic reactor systems. Both systems are compared based on current and removal efficiencies for ammonium, as well as the energy input required to drive ammonium transfer across the cation exchange membrane. Finally, a comparative analysis considering key aspects such as reliability, electrode cost, and rate is made. This video article and protocol provide the necessary information to conduct electrochemical and bioelectrochemical ammonia recovery experiments. The reactor setup for the two cases is explained, as well as the reactor operation. We elaborate on data analysis for both reactor types and on the advantages and disadvantages of bioelectrochemical and electrochemical systems.

Structure-biocompatibility and transfection activity relationships of cationic polyaspartamides with (dialkylamino)alkyl and alkyl or hydroxyalkyl side groups.

PubMed

Salakhieva, Diana; Shevchenko, Vesta; Németh, Csaba; Gyarmati, Benjámin; Szilágyi, András; Abdullin, Timur

2017-01-30

A series of 14 cationic derivatives of poly(aspartic acid) i.e. cationic polyaspartamides with different (dialkylamino)alkyl and alkyl or hydroxyalkyl side groups was synthesized by nucleophilic addition on polysuccinimide. The resulting polyaspartamides have moderate amphiphilic properties. Relationships between the structure and ratio of side groups and in vitro properties of polyaspartamides, including their cytotoxic and membrane-damaging activity towards human cell lines, primary skin fibroblasts and erythrocytes, were established and discussed. Cationic polyaspartamides vary in their DNA-binding, condensing and nuclease-protecting characteristics depending on the concentration ratio of (dialkylamino)alkyl and alkyl or hydroxyalkyl side groups. Effective cell transfection was achieved upon polyaspartamide-mediated plasmid DNA delivery in serum-free medium in the presence of chloroquine. Effect of serum proteins adsorption onto polyaspartamide based polyplexes, and the role of concentration of polyplexes in culture medium in their colloidal stability and transfection process were demonstrated. Synthesized polyaspartamides are biocompatible and long-acting gene carriers, which are applied to cells after dilution and without washing, thus providing transfection level comparable to that of commercial transfection reagent. Copyright © 2016 Elsevier B.V. All rights reserved.

Mechanisms of chemoresistance to alkylating agents in malignant glioma.

PubMed

Sarkaria, Jann N; Kitange, Gaspar J; James, C David; Plummer, Ruth; Calvert, Hilary; Weller, Michael; Wick, Wolfgang

2008-05-15

Intrinsic or acquired chemoresistance to alkylating agents is a major cause of treatment failure in patients with malignant brain tumors. Alkylating agents, the mainstay of treatment for brain tumors, damage the DNA and induce apoptosis, but the cytotoxic activity of these agents is dependent on DNA repair pathways. For example, O6-methylguanine DNA adducts can cause double-strand breaks, but this is dependent on a functional mismatch repair pathway. Thus, tumor cell lines deficient in mismatch repair are resistant to alkylating agents. Perhaps the most important mechanism of resistance to alkylating agents is the DNA repair enzyme O6-methylguanine methyltransferase, which can eliminate the cytotoxic O6-methylguanine DNA adduct before it causes harm. Another mechanism of resistance to alkylating agents is the base excision repair (BER) pathway. Consequently, efforts are ongoing to develop effective inhibitors of BER. Poly(ADP-ribose)polymerase plays a pivotal role in BER and is an important therapeutic target. Developing effective strategies to overcome chemoresistance requires the identification of reliable preclinical models that recapitulate human disease and which can be used to facilitate drug development. This article describes the diverse mechanisms of chemoresistance operating in malignant glioma and efforts to develop reliable preclinical models and novel pharmacologic approaches to overcome resistance to alkylating agents.

Alcohols as alkylating agents in heteroarene C-H functionalization

NASA Astrophysics Data System (ADS)

Jin, Jian; MacMillan, David W. C.

2015-09-01

Redox processes and radical intermediates are found in many biochemical processes, including deoxyribonucleotide synthesis and oxidative DNA damage. One of the core principles underlying DNA biosynthesis is the radical-mediated elimination of H2O to deoxygenate ribonucleotides, an example of `spin-centre shift', during which an alcohol C-O bond is cleaved, resulting in a carbon-centred radical intermediate. Although spin-centre shift is a well-understood biochemical process, it is underused by the synthetic organic chemistry community. We wondered whether it would be possible to take advantage of this naturally occurring process to accomplish mild, non-traditional alkylation reactions using alcohols as radical precursors. Because conventional radical-based alkylation methods require the use of stoichiometric oxidants, increased temperatures or peroxides, a mild protocol using simple and abundant alkylating agents would have considerable use in the synthesis of diversely functionalized pharmacophores. Here we describe the development of a dual catalytic alkylation of heteroarenes, using alcohols as mild alkylating reagents. This method represents the first, to our knowledge, broadly applicable use of unactivated alcohols as latent alkylating reagents, achieved via the successful merger of photoredox and hydrogen atom transfer catalysis. The value of this multi-catalytic protocol has been demonstrated through the late-stage functionalization of the medicinal agents, fasudil and milrinone.

Alcohols as alkylating agents in heteroarene C-H functionalization.

PubMed

Jin, Jian; MacMillan, David W C

2015-09-03

Redox processes and radical intermediates are found in many biochemical processes, including deoxyribonucleotide synthesis and oxidative DNA damage. One of the core principles underlying DNA biosynthesis is the radical-mediated elimination of H2O to deoxygenate ribonucleotides, an example of 'spin-centre shift', during which an alcohol C-O bond is cleaved, resulting in a carbon-centred radical intermediate. Although spin-centre shift is a well-understood biochemical process, it is underused by the synthetic organic chemistry community. We wondered whether it would be possible to take advantage of this naturally occurring process to accomplish mild, non-traditional alkylation reactions using alcohols as radical precursors. Because conventional radical-based alkylation methods require the use of stoichiometric oxidants, increased temperatures or peroxides, a mild protocol using simple and abundant alkylating agents would have considerable use in the synthesis of diversely functionalized pharmacophores. Here we describe the development of a dual catalytic alkylation of heteroarenes, using alcohols as mild alkylating reagents. This method represents the first, to our knowledge, broadly applicable use of unactivated alcohols as latent alkylating reagents, achieved via the successful merger of photoredox and hydrogen atom transfer catalysis. The value of this multi-catalytic protocol has been demonstrated through the late-stage functionalization of the medicinal agents, fasudil and milrinone.

40 CFR 721.10711 - Alkyl substituted catechol (generic).

Code of Federal Regulations, 2014 CFR

2014-07-01

...) TOXIC SUBSTANCES CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.10711 Alkyl substituted catechol (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as alkyl...

40 CFR 721.840 - Alkyl substituted diaromatic hydrocarbons.

Code of Federal Regulations, 2010 CFR

2010-07-01

... hydrocarbons. 721.840 Section 721.840 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... Specific Chemical Substances § 721.840 Alkyl substituted diaromatic hydrocarbons. (a) Chemical substance... alkyl substituted di-aro-matic hydrocarbons (PMN P-91-710) is subject to reporting under this section...

40 CFR 721.840 - Alkyl substituted diaromatic hydrocarbons.

Code of Federal Regulations, 2011 CFR

2011-07-01

... hydrocarbons. 721.840 Section 721.840 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... Specific Chemical Substances § 721.840 Alkyl substituted diaromatic hydrocarbons. (a) Chemical substance... alkyl substituted di-aro-matic hydrocarbons (PMN P-91-710) is subject to reporting under this section...

Effect of alkyl chain length on the rotational diffusion of nonpolar and ionic solutes in 1-alkyl-3-methylimidazolium-bis(trifluoromethylsulfonyl)imides.

PubMed

Gangamallaiah, V; Dutt, G B

2013-10-10

Rotational diffusion of a nonpolar solute 9-phenylanthracene (9-PA) and a cationic solute rhodamine 110 (R110) has been examined in a series of 1-alkyl-3-methylimidazolium (alkyl = octyl, decyl, dodecyl, tetradecyl, hexadecyl, and octadecyl) bis(trifluoromethylsulfonyl)imides to understand the influence of alkyl chain length on solute rotation. In this study, reorientation times (τr) have been measured as a function of viscosity (η) by varying the temperature (T) of the solvents. These results have been analyzed using the Stokes-Einstein-Debye (SED) hydrodynamic theory along with the ones obtained for the same solutes in 1-alkyl-3-methylimidazolium (alkyl = methyl, ethyl, propyl, butyl, and hexyl) bis(trifluoromethylsulfonyl)imides (Gangamallaiah and Dutt, J. Phys. Chem. B 2012, 116, 12819-12825). It has been noticed that the data for 9-PA and R110 follows the relation τr = A(η/T)(n) with A being the ratio of hydrodynamic volume of the solute to the Boltzmann constant and n = 1 as envisaged by the SED theory. However, upon increasing the alkyl chain length from methyl to octadecyl significant deviations from the SED theory have been observed especially from the octyl derivative onward. From methyl to octadecyl derivatives, the value of A decreases by a factor of 3 for both the solutes and n by a factor of 1.4 and 1.6 for 9-PA and R110, respectively. These observations have been rationalized by taking into consideration the organized structure of the ionic liquids, whose influence appears to be pronounced when the number of carbon atoms in the alkyl chain attached to the imidazolium cation exceeds eight.

Copper-catalyzed radical carbooxygenation: alkylation and alkoxylation of styrenes.

PubMed

Liao, Zhixiong; Yi, Hong; Li, Zheng; Fan, Chao; Zhang, Xu; Liu, Jie; Deng, Zixin; Lei, Aiwen

2015-01-01

A simple copper-catalyzed direct radical carbooxygenation of styrenes is developed utilizing alkyl bromides as radical resources. This catalytic radical difunctionalization accomplishes both alkylation and alkoxylation of styrenes in one pot. A broad range of styrenes and alcohols are well tolerated in this transformation. The EPR experiment shows that alkyl halides could oxidize Cu(I) to Cu(II) in this transformation. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Lithium perchlorate-nitromethane-promoted alkylation of anilines with arylmethanols.

PubMed

Zhou, Jun; Mao, Hai-Feng; Wang, Lu; Zou, Jian-Ping; Zhang, Wei

2011-11-01

A new application of lithium perchlorate-nitromethane (LPNM) for the formation of aromatic C-N and C-C bonds is introduced. LPNM-promoted reactions of anilines with diarylmethanols selectively generate N-alkylated anilines or mono and double Friedel-Crafts alkylation products under different conditions by changing the reaction time, reaction temperature, and the ratio of the reactants. This method does not require the use of transition metal catalysts to prepare alkylated aniline derivatives.

Grafted methylenediphosphonate ion exchange resins

DOEpatents

Trochimcznk, A.W.; Gatrone, R.C.; Alexandratos, S.; Horwitz, E.P.

1997-04-08

An ion exchange resin is disclosed that is comprised of an insoluble copolymer onto which are grafted pendent groups that provide 1.0 to about 10 mmol/g dry weight phosphorus. The pendent groups have the formula as shown in the patent wherein R is hydrogen, a cation or mixtures thereof; and R{sup 1} is hydrogen or an C{sub 1}-C{sub 2} alkyl group. The resin also contains zero to about 5 mmol/g dry weight of pendent aromatic sulfonate groups. Processes for making and using an ion exchange resin are also disclosed.

Chiral Brønsted Base-Promoted Nitroalkane Alkylation: Enantioselective Synthesis of sec-Alkyl-3-Substituted Indoles

PubMed Central

Dobish, Mark C.; Johnston, Jeffrey N.

2010-01-01

A Brønsted base-catalyzed reaction of nitroalkanes with alkyl electrophiles provides indole heterocycles substituted at C3 bearing a sec-alkyl group with good enantioselectivity (up to 90% ee). Denitration by hydrogenolysis provides a product with equally high ee. An indolenine intermediate is implicated in the addition step, and surprisingly, water cosolvent was found to have a beneficial effect in this step, leading to a one-pot protocol for elimination/enantioselective addition using PBAM, a bis(amidine) chiral nonracemic base. PMID:21090654

ELUTION OF URANIUM VALUES FROM ION EXCHANGE RESINS

DOEpatents

Kennedy, R.H.

1959-11-24

A process is described for eluting complex uranium ions absorbed on ion exchange resins. The resin is subjected to the action of an aqueous eluting solution contuining sulfuric acid and an alkali metal, ammonium, or magnesium chloride or nitrate, the elution being carried out until the desired amount of the uranium is removed from the resin.

Protein Precipitation Using Ammonium Sulfate.

PubMed

2016-04-01

The basic theory of protein precipitation by addition of ammonium sulfate is presented, and the most common applications are listed. Tables are provided for calculating the appropriate amount of ammonium sulfate to add to a particular protein solution. Copyright © 2016 John Wiley & Sons, Inc.

Atomic absorption spectroscopic, conductometric and colorimetric methods for determination of fluoroquinolone antibiotics using ammonium reineckate ion-pair complex formation

NASA Astrophysics Data System (ADS)

Ragab, Gamal H.; Amin, Alaa S.

2004-03-01

Three accurate, rapid and simple atomic absorption spectrometric, conductometric and colorimetric methods were developed for the determination of norfloxacin (NRF), ciprofloxacin (CIP), ofloxacin (OFL) and enrofloxacin (ENF). The proposed methods depend upon the reaction of ammonium reineckate with the studied drugs to form stable precipitate of ion-pair complexes, which was dissolved in acetone. The pink coloured complexes were determined either by AAS or colorimetrically at λmax 525 nm directly using the dissolved complex. Using conductometric titration, the studied drugs could be evaluated in 50% (v/v) acetone in the range 5.0-65, 4.0-48, 5.0-56 and 6.0-72 μg ml -1 of NRF, CPF, OFL and ENF, respectively. The optimizations of various experimental conditions were described. The results obtained showed good recoveries of 99.15±1.15, 99.30±1.40, 99.60±1.50, and 99.00±1.25% with relative standard deviations of 0.81, 1.06, 0.97, and 0.69% for NRF, CPF, OFL, and ENF, respectively. Applications of the proposed methods to representative pharmaceutical formulations are successfully presented.

Sorption of uranyl ions from various acido systems by amphoteric epoxy amine ion-exchange resins

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rychkov, V.N.; Radionov, B.K.; Molochnikov, L.S.

1995-03-01

Sorption of uranyl ions by epoxy amine ampholytes with N-monomethylenephosphonic acid groups modified with pyridine or quaternary ammonium groups was studied under dynamic conditions. Heterocyclic nitrogen favors sorption of uranyl ion from fluoride, sulfate, and fluoride-sulfate solutions. The ESR studies of mono- and bimetallic forms of nitrogen-containing ampholytes with copper(II) as paramagnetic marker revealed the characteristics of uranium(VI) interaction with cation- and anion-exchange groups and its dependence on the fluoride content in solution.

Sleep-inducing N-alkyl-5-[m-(trifluoromethyl)phenyl]-5-hydroxy-2-pyrrolidinones and N-alkyl-3-(trifluoromethyl)cinnamamides.

PubMed

Houlihan, W J; Gogerty, J H; Ryan, E A; Schmitt, G

1985-01-01

A series of N-alkyl-3-[m-(trifluoromethyl)phenyl]-5-hydroxy-2-pyrrolidinones and N-alkyl-3-(trifluoromethyl)-cinnamamides were prepared and screened in a series of tests designed to detect potential sleep inducers. The more active members of the series were evaluated for their ability to induce sleep in Cebus monkeys. The most active compound, N-methyl-5-[m-(trifluoromethyl)phenyl]-5-hydroxy-2-pyrrolidinone, was equal to methaqualone.

Removal of ammonium ion from produced waters in petroleum offshore exploitation by a batch single-stage electrolytic process.

PubMed

de Lima, Rosilda Maria Gomes; da Silva Wildhagen, Glória Regina; da Cunha, José Waldemar Silva Dias; Afonso, Julio Carlos

2009-01-30

This work describes a batch single-stage electrochemical process to remove quantitatively the ammonium ion from produced waters from petroleum exploration of the Campos' Basin, seeking to fulfil the directories of the National Brazilian Environmental Council. The anode was made out of titanium covered by a layer of RuO(2)+TiO(2) oxides (Dimensionally Stable Anode), whereas the cathode was made out of pure titanium. Anodic and cathodic compartments were separated by a membrane. The applied current varied from 0.3 to 1.5A. As the current increased NH(4)(+) removal was faster and pH was rapidly decreased to 3. The pH of the anodic compartment increased to approximately 10. When the current was 0.92 A chlorine evolution was observed after 40 min or only 15 min when that current was 1.50 A. In this voltage a deposit containing alkali-earth metal hydroxides/sulphates was formed on the membrane surface of the cathode side, thus suggesting a diffusion process from the anodic to the cathodic compartment. The maximum current applied to the cell must not exceed approximately 0.70 A in order to avoid chlorine evolution. Ammonia removal was over 99.9 wt% at 0.68 A in about 75 min.

Structure-activity relationship of the ionic cocrystal: 5-amino-2-naphthalene sulfonate·ammonium ions for pharmaceutical applications

NASA Astrophysics Data System (ADS)

Sangeetha, M.; Mathammal, R.

2018-02-01

The ionic cocrystals of 5-amino-2-naphthalene sulfonate · ammonium ions (ANSA-ṡNH4+) were grown under slow evaporation method and examined in detail for pharmaceutical applications. The crystal structure and intermolecular interactions were studied from the single X-ray diffraction analysis and the Hirshfeld surfaces. The 2D fingerprint plots displayed the inter-contacts possible in the ionic crystal. Computational DFT method was established to determine the structural, physical and chemical properties. The molecular geometries obtained from the X-ray studies were compared with the optimized geometrical parameters calculated using DFT/6-31 + G(d,p) method. The band gap energy calculated from the UV-Visible spectral analysis and the HOMO-LUMO energy gap are compared. The theoretical UV-Visible calculations helped in determining the type of electronic transition taking place in the title molecule. The maximum absorption bands and transitions involved in the molecule represented the drug reaction possible. Non-linear optical properties were characterized from SHG efficiency measurements experimentally and the NLO parameters are also calculated from the optimized structure. The reactive sites within the molecule are detailed from the MEP surface maps. The molecular docking studies evident the structure-activity of the ionic cocrystal for anti-cancer drug property.

Synthesis and characterization of chitosan alkyl urea.

PubMed

Wang, Jing; Jiang, Ji-Zhou; Chen, Wei; Bai, Zheng-Wu

2016-07-10

Chitosan is a versatile material employed for various purposes in many fields including the development of chiral stationary phases for enantioseparation. Chitosan alkyl urea is a kind of intermediate used to prepare enantioseparation materials. In order to synthesize the intermediates, in the present work, a new way to prepare chitosan alkyl urea has been established: chitosan was first reacted with methyl chloroformate yielding N-methoxyformylated chitosan, which was then converted to chitosan alkyl urea through amine-ester exchange reaction. With a large excess of methyl chloroformate and primary amine of low stereohindrance, the amino group in chitosan could be almost completely converted to ureido group. The as-prepared chitosan alkyl urea derivatives were characterized by IR, (1)H NMR, (13)C NMR,(1)H-(1)H COSY and (1)H-(13)C HSQC NMR spectra. The chemical shifts of hydrogen and carbon atoms of glucose unit were assigned. It was found that the degree of substitution was obviously lower if cyclopropyl amine, aniline, tert-butyl amine and diethyl amine were used as reactants for the amine-ester exchange reaction. The reason was explained with the aid of theoretical calculations. Copyright © 2016 Elsevier Ltd. All rights reserved.

Alcohols as alkylating agents in heteroarene C–H functionalization

PubMed Central

Jin, Jian; MacMillan, David W. C.

2015-01-01

Redox processes and radical intermediates are found in many biochemical processes, including deoxyribonucleotide synthesis and oxidative DNA damage1. One of the core principles that underlies DNA biosynthesis is the radical-mediated elimnation of H2O to deoxygenate ribonucleotides, an example of ‘spin-center shift’ (SCS)2, during which an alcohol C–O bond is cleaved, resulting in a carbon-centered radical intermediate. While SCS is a well-understood biochemical process, it is underutilized by the synthetic organic chemistry community. We wondered whether it would be possible to take advantage of this naturally occurring process to accomplish mild, non-traditional alkylations using alcohols as radical precursors. Considering traditional radical-based alkylation methods require the use of stoichiometric oxidants, elevated temperatures, or peroxides3–7, the development of a mild protocol using simple and abundant alkylating agents would have significant utility in the synthesis of diversely functionalized pharmacophores. In this manuscript, we describe the successful execution of this idea via the development of a dual catalytic alkylation of heteroarenes using alcohols as mild alkylating reagents. This method represents the first broadly applicable use of unactivated alcohols as latent alkylating reagents, achieved via the successful merger of photoredox and hydrogen atom transfer (HAT) catalysis. The utility of this multi-catalytic protocol has been demonstrated through the late-stage functionalization of the medicinal agents, fasudil and milrinone. PMID:26308895

Differences in Steady-State Net Ammonium and Nitrate Influx by Cold- and Warm-Adapted Barley Varieties 1

PubMed Central

Bloom, Arnold J.; Chapin, F. Stuart

1981-01-01

A flowing nutrient culture system permitted relatively rapid determination of the steady-state net nitrogen influx by an intact barley (Hardeum vulgare L. cv Kombar and Olli) plant. Ion-selective electrodes monitored the depletion of ammonium and nitrate from a nutrient solution after a single pass through a root cuvette. Influx at concentrations as low as 4 micromolar was measured. Standard errors for a sample size of three plants were typically less than 10% of the mean. When grown under identical conditions, a variety of barley bred for cold soils had higher nitrogen influx rates at low concentrations and low temperatures than one bred for warm soils, whereas the one bred for warm soils had higher influx rates at high concentrations and high temperatures. Ammonium was more readily absorbed than nitrate by both varieties at all concentrations and temperatures tested. Ammonium and nitrate influx in both varieties were equally inhibited by low temperatures. PMID:16662052

21 CFR 182.1127 - Aluminum ammonium sulfate.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Aluminum ammonium sulfate. 182.1127 Section 182.1127 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... Food Substances § 182.1127 Aluminum ammonium sulfate. (a) Product. Aluminum ammonium sulfate. (b...

21 CFR 582.1127 - Aluminum ammonium sulfate.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Aluminum ammonium sulfate. 582.1127 Section 582.1127 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... Additives § 582.1127 Aluminum ammonium sulfate. (a) Product. Aluminum ammonium sulfate. (b) Conditions of...

21 CFR 182.1127 - Aluminum ammonium sulfate.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Aluminum ammonium sulfate. 182.1127 Section 182.1127 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... Food Substances § 182.1127 Aluminum ammonium sulfate. (a) Product. Aluminum ammonium sulfate. (b...

21 CFR 182.1127 - Aluminum ammonium sulfate.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Aluminum ammonium sulfate. 182.1127 Section 182.1127 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... Food Substances § 182.1127 Aluminum ammonium sulfate. (a) Product. Aluminum ammonium sulfate. (b...

21 CFR 582.1127 - Aluminum ammonium sulfate.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Aluminum ammonium sulfate. 582.1127 Section 582.1127 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... Additives § 582.1127 Aluminum ammonium sulfate. (a) Product. Aluminum ammonium sulfate. (b) Conditions of...

21 CFR 582.1127 - Aluminum ammonium sulfate.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Aluminum ammonium sulfate. 582.1127 Section 582.1127 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... Additives § 582.1127 Aluminum ammonium sulfate. (a) Product. Aluminum ammonium sulfate. (b) Conditions of...

21 CFR 582.1127 - Aluminum ammonium sulfate.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Aluminum ammonium sulfate. 582.1127 Section 582.1127 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... Additives § 582.1127 Aluminum ammonium sulfate. (a) Product. Aluminum ammonium sulfate. (b) Conditions of...

21 CFR 182.1127 - Aluminum ammonium sulfate.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Aluminum ammonium sulfate. 182.1127 Section 182.1127 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... Food Substances § 182.1127 Aluminum ammonium sulfate. (a) Product. Aluminum ammonium sulfate. (b...

21 CFR 73.1298 - Ferric ammonium ferrocyanide.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 1 2011-04-01 2011-04-01 false Ferric ammonium ferrocyanide. 73.1298 Section 73... LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1298 Ferric ammonium ferrocyanide. (a) Identity. (1) The color additive ferric ammonium ferrocyanide is the blue pigment obtained by oxidizing...

Kinetic Effect on the Freezing of Ammonium-Sodium-Carbonate-Chloride Brines and Implications for Origin of Ceres' Bright Spots

NASA Astrophysics Data System (ADS)

Hodyss, R. P.; Thomas, E. C.; Vu, T. H.; Johnson, P. V.; Choukroun, M.

2017-12-01

Subsurface brines on Ceres containing natrite (Na2CO3) and smaller amounts of NH4Cl or NH4HCO3 have been proposed to reach the dwarf planet's surface from an internal reservoir, where the brines freeze and result in bright spots across Ceres. Kinetically frozen solutions containing the likely constituents of Ceres' subsurface brines (ammonium, sodium, carbonate, and chloride ions) were studied via infrared and micro-Raman spectroscopy, where the flash-frozen mixtures were found to preferentially form ammonium chloride and ammonium bicarbonate, even in sodium-dominated solutions. Additionally, sodium chloride only formed when sodium or chloride (or both) were present in excess in the brine solutions. Raman spectroscopy was further employed to analyze the effect of vacuum exposure on these frozen brines over longer periods of time to simulate the surface conditions of Ceres.

Understanding the impact of the central atom on the ionic liquid behavior: phosphonium vs ammonium cations.

PubMed

Carvalho, Pedro J; Ventura, Sónia P M; Batista, Marta L S; Schröder, Bernd; Gonçalves, Fernando; Esperança, José; Mutelet, Fabrice; Coutinho, João A P

2014-02-14

The influence of the cation's central atom in the behavior of pairs of ammonium- and phosphonium-based ionic liquids was investigated through the measurement of densities, viscosities, melting temperatures, activity coefficients at infinite dilution, refractive indices, and toxicity against Vibrio fischeri. All the properties investigated are affected by the cation's central atom nature, with ammonium-based ionic liquids presenting higher densities, viscosities, melting temperatures, and enthalpies. Activity coefficients at infinite dilution show the ammonium-based ionic liquids to present slightly higher infinite dilution activity coefficients for non-polar solvents, becoming slightly lower for polar solvents, suggesting that the ammonium-based ionic liquids present somewhat higher polarities. In good agreement these compounds present lower toxicities than the phosphonium congeners. To explain this behavior quantum chemical gas phase DFT calculations were performed on isolated ion pairs at the BP-TZVP level of theory. Electronic density results were used to derive electrostatic potentials of the identified minimum conformers. Electrostatic potential-derived CHelpG and Natural Population Analysis charges show the P atom of the tetraalkylphosphonium-based ionic liquids cation to be more positively charged than the N atom in the tetraalkylammonium-based analogous IL cation, and a noticeable charge delocalization occurring in the tetraalkylammonium cation, when compared with the respective phosphonium congener. It is argued that this charge delocalization is responsible for the enhanced polarity observed on the ammonium based ionic liquids explaining the changes in the thermophysical properties observed.

Understanding the impact of the central atom on the ionic liquid behavior: Phosphonium vs ammonium cations

NASA Astrophysics Data System (ADS)

Carvalho, Pedro J.; Ventura, Sónia P. M.; Batista, Marta L. S.; Schröder, Bernd; Gonçalves, Fernando; Esperança, José; Mutelet, Fabrice; Coutinho, João A. P.

2014-02-01

The influence of the cation's central atom in the behavior of pairs of ammonium- and phosphonium-based ionic liquids was investigated through the measurement of densities, viscosities, melting temperatures, activity coefficients at infinite dilution, refractive indices, and toxicity against Vibrio fischeri. All the properties investigated are affected by the cation's central atom nature, with ammonium-based ionic liquids presenting higher densities, viscosities, melting temperatures, and enthalpies. Activity coefficients at infinite dilution show the ammonium-based ionic liquids to present slightly higher infinite dilution activity coefficients for non-polar solvents, becoming slightly lower for polar solvents, suggesting that the ammonium-based ionic liquids present somewhat higher polarities. In good agreement these compounds present lower toxicities than the phosphonium congeners. To explain this behavior quantum chemical gas phase DFT calculations were performed on isolated ion pairs at the BP-TZVP level of theory. Electronic density results were used to derive electrostatic potentials of the identified minimum conformers. Electrostatic potential-derived CHelpG and Natural Population Analysis charges show the P atom of the tetraalkylphosphonium-based ionic liquids cation to be more positively charged than the N atom in the tetraalkylammonium-based analogous IL cation, and a noticeable charge delocalization occurring in the tetraalkylammonium cation, when compared with the respective phosphonium congener. It is argued that this charge delocalization is responsible for the enhanced polarity observed on the ammonium based ionic liquids explaining the changes in the thermophysical properties observed.

ZnO twin-cones: synthesis, photoluminescence, and catalytic decomposition of ammonium perchlorate.

PubMed

Sun, Xuefei; Qiu, Xiaoqing; Li, Liping; Li, Guangshe

2008-05-19

ZnO twin-cones, a new member to the ZnO family, were prepared directly by a solvothermal method using a mixed solution of zinc nitrate and ethanol. The reaction and growth mechanisms of ZnO twin-cones were investigated by X-ray diffraction, UV-visible spectra, infrared and ion trap mass spectra, and transmission electron microscopy. All as-prepared ZnO cones consisted of tiny single crystals with lengths of several micrometers. With prolonging of the reaction time from 1.5 h to 7 days, the twin-cone shape did not change at all, while the lattice parameters increased slightly and the emission peak of photoluminescence shifted from the green region to the near orange region. ZnO twin-cones are also explored as an additive to promote the thermal decomposition of ammonium perchlorate. The variations of photoluminescence spectra and catalytic roles in ammonium perchlorate decomposition were discussed in terms of the defect structure of ZnO twin-cones.

Quaternary ammonium isobaric tag for a relative and absolute quantification of peptides.

PubMed

Setner, Bartosz; Stefanowicz, Piotr; Szewczuk, Zbigniew

2018-02-01

Isobaric labeling quantification of peptides has become a method of choice for mass spectrometry-based proteomics studies. However, despite of wide variety of commercially available isobaric tags, none of the currently available methods offers significant improvement of sensitivity of detection during MS experiment. Recently, many strategies were applied to increase the ionization efficiency of peptides involving chemical modifications introducing quaternary ammonium fixed charge. Here, we present a novel quaternary ammonium-based isobaric tag for relative and absolute quantification of peptides (QAS-iTRAQ 2-plex). Upon collisional activation, the new stable benzylic-type cationic reporter ion is liberated from the tag. Deuterium atoms were used to offset the differential masses of a reporter group. We tested the applicability of QAS-iTRAQ 2-plex reagent on a series of model peptides as well as bovine serum albumin tryptic digest. Obtained results suggest usefulness of this isobaric ionization tag for relative and absolute quantification of peptides. Copyright © 2017 John Wiley & Sons, Ltd.

Automated, colorimetric methods for determination of nitrate plus nitrite, nitrite, ammonium and orthophosphate ions in natural water samples

USGS Publications Warehouse

Antweiler, Ronald C.; Patton, Charles J.; Taylor, Howard E.

1996-01-01

The apparatus and methods used for the automatic, colorimetric determinations of dissolved nutrients (nitrate plus nitrite, nitrite, ammonium and orthophosphate) in natural waters are described. These techniques allow for the determination of nitrate plus nitrite for the concentration range 0.02 to 8 mg/L (milligrams per liter) as N (nitrogen); for nitrite, the range is 0.002 to 1.0 mg/L as N; for ammonium, the range is 0.006 to 2.0 mg/L as N; and for orthophosphate, the range is 0.002 to 1.0 mg/L as P (phosphorus). Data are presented that demonstrate the accuracy, precision and quality control of the methods.

21 CFR 582.1137 - Ammonium carbonate.

Code of Federal Regulations, 2010 CFR

2010-04-01

... Additives § 582.1137 Ammonium carbonate. (a) Product. Ammonium carbonate. (b) Conditions of use. This substance is generally recognized as safe when used in accordance with good manufacturing or feeding...

21 CFR 582.1139 - Ammonium hydroxide.

Code of Federal Regulations, 2010 CFR

2010-04-01

... Additives § 582.1139 Ammonium hydroxide. (a) Product. Ammonium hydroxide. (b) Conditions of use. This substance is generally recognized as safe when used in accordance with good manufacturing or feeding...

21 CFR 582.1135 - Ammonium bicarbonate.

Code of Federal Regulations, 2010 CFR

2010-04-01

... Additives § 582.1135 Ammonium bicarbonate. (a) Product. Ammonium bicarbonate. (b) Conditions of use. This substance is generally recognized as safe when used in accordance with good manufacturing or feeding...

21 CFR 582.1137 - Ammonium carbonate.

Code of Federal Regulations, 2013 CFR

2013-04-01

... Additives § 582.1137 Ammonium carbonate. (a) Product. Ammonium carbonate. (b) Conditions of use. This substance is generally recognized as safe when used in accordance with good manufacturing or feeding...

21 CFR 582.1137 - Ammonium carbonate.

Code of Federal Regulations, 2011 CFR

2011-04-01

... Additives § 582.1137 Ammonium carbonate. (a) Product. Ammonium carbonate. (b) Conditions of use. This substance is generally recognized as safe when used in accordance with good manufacturing or feeding...

21 CFR 582.1139 - Ammonium hydroxide.

Code of Federal Regulations, 2012 CFR

2012-04-01

... Additives § 582.1139 Ammonium hydroxide. (a) Product. Ammonium hydroxide. (b) Conditions of use. This substance is generally recognized as safe when used in accordance with good manufacturing or feeding...

21 CFR 582.1137 - Ammonium carbonate.

Code of Federal Regulations, 2012 CFR

2012-04-01

... Additives § 582.1137 Ammonium carbonate. (a) Product. Ammonium carbonate. (b) Conditions of use. This substance is generally recognized as safe when used in accordance with good manufacturing or feeding...

21 CFR 582.1137 - Ammonium carbonate.

Code of Federal Regulations, 2014 CFR

2014-04-01

... Additives § 582.1137 Ammonium carbonate. (a) Product. Ammonium carbonate. (b) Conditions of use. This substance is generally recognized as safe when used in accordance with good manufacturing or feeding...

21 CFR 582.1139 - Ammonium hydroxide.

Code of Federal Regulations, 2013 CFR

2013-04-01

... Additives § 582.1139 Ammonium hydroxide. (a) Product. Ammonium hydroxide. (b) Conditions of use. This substance is generally recognized as safe when used in accordance with good manufacturing or feeding...

21 CFR 582.1139 - Ammonium hydroxide.

Code of Federal Regulations, 2014 CFR

2014-04-01

... Additives § 582.1139 Ammonium hydroxide. (a) Product. Ammonium hydroxide. (b) Conditions of use. This substance is generally recognized as safe when used in accordance with good manufacturing or feeding...

21 CFR 582.1139 - Ammonium hydroxide.

Code of Federal Regulations, 2011 CFR

2011-04-01

... Additives § 582.1139 Ammonium hydroxide. (a) Product. Ammonium hydroxide. (b) Conditions of use. This substance is generally recognized as safe when used in accordance with good manufacturing or feeding...

PROCESS FOR THE PRODUCTION OF AMMONIUM URANIUM FLUORIDE

DOEpatents

Ellis, A.S.; Mooney, R.B.

1953-08-25

This patent relates to the preparation of ammonium uranium fluoride. The process comprises adding a water soluble fluoride to an aqueous solution of a uranous compound containing an ammonium salt, and isolating the resulting precipitate. This patent relates to the manufacture of uranium tetnafluoride from ammonium uranium fluoride, NH/sub 4/UF/sub 5/. Uranium tetrafluoride is prepared by heating the ammonium uranium fluoride to a temperature at which dissociation occurs with liberation of ammonium fluoride. Preferably the process is carried out under reduced pressure, or in a current of an inert gas.

Detection of Alkylating Agents using Electrical and Mechanical Means

NASA Astrophysics Data System (ADS)

Gerchikov, Yulia; Borzin, Elena; Gannot, Yair; Shemesh, Ariel; Meltzman, Shai; Hertzog-Ronen, Carmit; Tal, Shay; Stolyarova, Sara; Nemirovsky, Yael; Tessler, Nir; Eichen, Yoav

2011-08-01

Alkylating agents are reactive molecules having at least one polar bond between a carbon atom and a good leaving group. These often simple molecules are frequently used in organic synthesis, as sterilizing agents in agriculture and even as anticancer agents in medicine. Unfortunately, for over a century, some of the highly reactive alkylating agents are also being used as blister chemical warfare agents. Being relatively simple to make, the risk is that these will be applied by terrorists as poor people warfare agents. The detection and identification of such alkylating agents is not a simple task because of their high reactivity and simple structure of the reactive site. Here we report on new approaches to the detection and identification of such alkylating agents using electrical (organic field effect transistors) and mechanical (microcantilevers) means.

Evidence for ammonium-bearing minerals in Ceres

NASA Technical Reports Server (NTRS)

King, T. V. V.; Clark, R. N.; Calvin, W. M.; Sherman, D. M.; Swayze, G. A.; Brown, R. H.

1991-01-01

Evidence for ammonium-bearing minerals was found on the surface of the largest asteroid Ceres. The presence of ammonium-bearing clays suggests that Ceres has experienced a period of alteration by substantial amounts of an ammonium-bearing fluid. The presence of the ammonium-bearing clays does not preclude Ceres maintaining a volatile inventory in the core or in a volatile-rich zone at some distance below the surface. Telescopic observations of Ceres, using the 3.0 meter NASA Infrared telescope facility prompted this reevaluation of its surface mineralogy.

Safety Assessment of Alkyl PEG/PPG Ethers as Used in Cosmetics.

PubMed

Fiume, Monice M; Heldreth, Bart; Bergfeld, Wilma F; Belsito, Donald V; Hill, Ronald A; Klaassen, Curtis D; Liebler, Daniel C; Marks, James G; Shank, Ronald C; Slaga, Thomas J; Snyder, Paul W; Andersen, F Alan

2016-07-01

The Cosmetic Ingredient Review (CIR) Expert Panel assessed the safety of 131 alkyl polyethylene glycol (PEG)/polypropylene glycol ethers as used in cosmetics, concluding that these ingredients are safe in the present practices of use and concentration described in this safety assessment when formulated to be nonirritating. Most of the alkyl PEG/PPG ethers included in this review are reported to function in cosmetics as surfactants, skin-conditioning agents, and/or emulsifying agents. The alkyl PEG/PPG ethers share very similar physiochemical properties as the alkyl PEG ethers, which were reviewed previously by the CIR Expert Panel and found safe when formulated to be nonirritating. The alkyl PEG ethers differ by the inclusion of PPG repeat units, which are used to fine-tune the surfactant properties of this group. The Panel relied heavily on data on analogous ingredients, extracted from the alkyl PEG ethers and PPG reports, when making its determination of safety. © The Author(s) 2016.

21 CFR 582.1143 - Ammonium sulfate.

Code of Federal Regulations, 2010 CFR

2010-04-01

... Additives § 582.1143 Ammonium sulfate. (a) Product. Ammonium sulfate. (b) Conditions of use. This substance is generally recognized as safe when used in accordance with good manufacturing or feeding practice. ...

Start-up of simultaneous removal of ammonium and sulfate from an anaerobic ammonium oxidation (anammox) process in an anaerobic up-flow bioreactor.

PubMed

Yang, Zhiquan; Zhou, Shaoqi; Sun, Yanbo

2009-09-30

A laboratory testing of simultaneous removal of ammonium and sulfate (SRAS) was studied from an anammox process in an anaerobic bioreactor filled with granular activated carbon. Two different phases of experiment were investigated to start up the SRAS process, and final batch tests were performed to analyze the SRAS process. The experiment included an anammox process and an SRAS process. During the anammox process, the highest removal efficiency of ammonium and nitrite was up to 97 and 98%, respectively. After 160 days in the stationary phase of anammox process, the ratio of ammonium to nitrite consumption was approximately 1:1.15, which is much higher than 1:1.32 in the traditional anammox process. The extra electron acceptor, such as sulfate, was thought to react with ammonium by bacteria. Synthetic wastewater containing ammonium chlorine and sodium sulfate was used as the feed for the bioreactor in the second phase of experiment. During the SRAS process, the influent concentrations of ammonium and sulfate were controlled to be 50-60 and 210-240 mg L(-1) respectively. After start-up and acclimatization of this process for 60 days, the average effluent concentrations of ammonium and sulfate were 30 and 160 mg L(-1), respectively. The simultaneous ammonium and sulfate removal was detected in the reactor. In order to further validate the biochemical interaction between ammonium and sulfate, batch tests was carried out. Abiotic tests were carried out to demonstrate that the pure chemical action between ammonium and sulfate without microorganism was not possible. Biotic assays with different ammonium and sulfate concentrations were further investigated that high concentrations of ammonium and sulfate could promote simultaneous removal of ammonium and sulfate. And elemental sulfur and nitrogen gas as the products measured in the SRAS process helped to demonstrate the occurrence of new interaction between nitrogen and sulfur. The new process of SRAS in the inorganic

Alkylation of 6-mercaptopurine (6-MP) with N-alkyl-N-alkoxycarbonylaminomethyl chlorides: S6-(N-alkyl-N-alkoxycarbonyl)aminomethyl-6-MP prodrug structure effect on the dermal delivery of 6-MP.

PubMed

Siver, K G; Sloan, K B

1990-01-01

The S6-(N-alkyl-N-alkoxycarbonyl)aminomethyl-6-MP (6-CARB-6-MP) prodrugs 5-20 were synthesized from the reaction of 6-MP with N-alkyl-N-alkyoxycarbonylaminomethyl chlorides (4) in dimethyl sulfoxide in overall yields of 5-62%, depending on the N-alkyl and the alkoxy groups involved. The derivatives were fully characterized by spectral and microanalyses. The assignment of the substitution pattern as S6-alkyl was based on comparisons of the UV, 1H NMR and 13C NMR spectra with model compounds. A S6, 9-bis-alkyl derivative was obtained from the reaction of 2 equivalents of 4 with 6-MP but the product was unstable and decomposed on standing to a 9-alkyl derivative. The 6-CARB-6-MP prodrugs reverted to 6-MP in water by an SN1-type mechanism involving unimolecular charge separation in the transition state of the rate determining step. There was no effect of dermal enzymes on the rate of hydrolysis. The solubilities in isopropyl myristate (IPM) for all of the 6-CARB-6-MP prodrugs were significantly greater than the solubility of 6-MP in IPM but only one prodrug (5) was apparently even as soluble as 6-MP in water. Selected 6-CARB-6-MP prodrugs were examined in diffusion cell experiments. Only the N-methyl-N-methoxycarbonyl derivative 5 gave a steady-state rate of delivery of 6-MP from IPM that was significantly greater than the steady-state rate of delivery of 6-MP from 6-MP in IPM. All the other derivatives gave steady-state rates of delivery of 6-MP from IPM that were either not significantly different, or were significantly lower than the rate obtained from 6-MP in IPM. In all cases, the effect of the 6-CARB-6-MP:IPM suspensions on the permeability of the skin, as determined by the second application flux of theophylline:propylene glycol, was of the same magnitude as the effect of IPM alone.

Electricity production coupled to ammonium in a microbial fuel cell.

PubMed

He, Zhen; Kan, Jinjun; Wang, Yanbing; Huang, Yuelong; Mansfeld, Florian; Nealson, Kenneth H

2009-05-01

The production of electricity from ammonium was examined using a rotating-cathode microbial fuel cell (MFC). The addition of ammonium chloride, ammonium sulfate, or ammonium phosphate (monobasic) resulted in electricity generation, while adding sodium chloride, nitrate, or nitrite did not cause any increase in current production. The peak current increased with increasing amount of ammonium addition up to 62.3 mM of ammonium chloride, suggesting that ammonium was involved in electricity generation either directly as the anodic fuel or indirectly as substrates for nitrifiers to produce organic compounds for heterotrophs. Adding nitrate or nitrite with ammonium increased current production compared to solely ammonium addition. Using 16S rRNA-linked molecular analyses, we found ammonium-oxidizing bacteria and denitrifying bacteria on both the anode and cathode electrodes, whereas no anammox bacteria were detected. The dominant ammonium-oxidizing bacteria were closely related to Nitrosomonas europaea. The present MFC achieved an ammonium removal efficiency of 49.2 +/- 5.9 or 69.7 +/- 3.6%, depending on hydraulic retention time, but exhibited a very low Coulombic efficiency.

Ultrasound promoted N-alkylation of pyrrole using potassium superoxide as base in crown ether.

PubMed

Yim, E S; Park, M K; Han, B H

1997-04-01

Ultrasound accelerates the N-alkylation of pyrrole by alkylating reagents using potassium superoxide as base in the presence of 18-crown-6. A much lower yield of N-alkylated pyrrole was realized in the absence of ultrasound. N-alkylating reagents employed for pyrrole are methyl iodide, ethyl bromide, benzyl bromide, as well as acrylonitrile allyl cyanide and methyl acrylate. In an extension of this work, we have found that ultrasound was not necessary for the N-alkylation of indole and alkyl amine, such as diphenyl amine and piperidine with alkyl halides using our reagents. In all cases we observed that the 18-crown-6 catalyzed N-alkylation reaction gives higher yields of N-alkylated products than that without crown ether, when potassium superoxide was used as base. These observations are probably due to the potassium-crown complex which can be released when the reaction goes to completion.

Bifunctional Molybdenum Polyoxometalates for the Combined Hydrodeoxygenation and Alkylation of Lignin-Derived Model Phenolics.

PubMed

Anderson, Eric; Crisci, Anthony; Murugappan, Karthick; Román-Leshkov, Yuriy

2017-05-22

Reductive catalytic fractionation of biomass has recently emerged as a powerful lignin extraction and depolymerization method to produce monomeric aromatic oxygenates in high yields. Here, bifunctional molybdenum-based polyoxometalates supported on titania (POM/TiO 2 ) are shown to promote tandem hydrodeoxygenation (HDO) and alkylation reactions, converting lignin-derived oxygenated aromatics into alkylated benzenes and alkylated phenols in high yields. In particular, anisole and 4-propylguaiacol were used as model compounds for this gas-phase study using a packed-bed flow reactor. For anisole, 30 % selectivity for alkylated aromatic compounds (54 % C-alkylation of the methoxy groups by methyl balance) with an overall 72 % selectivity for HDO at 82 % anisole conversion was observed over H 3 PMo 12 O 40 /TiO 2 at 7 h on stream. Under similar conditions, 4-propylguaiacol was mainly converted into 4-propylphenol and alkylated 4-propylphenols with a selectivity to alkylated 4-propylphenols of 42 % (77 % C-alkylation) with a total HDO selectivity to 4-propylbenzene and alkylated 4-propylbenzenes of 4 % at 92 % conversion (7 h on stream). Higher catalyst loadings pushed the 4-propylguaiacol conversion to 100 % and resulted in a higher selectivity to propylbenzene of 41 %, alkylated aromatics of 21 % and alkylated phenols of 17 % (51 % C-alkylation). The reactivity studies coupled with catalyst characterization revealed that Lewis acid sites act synergistically with neighboring Brønsted acid sites to simultaneously promote alkylation and hydrodeoxygenation activity. A reaction mechanism is proposed involving activation of the ether bond on a Lewis acid site, followed by methyl transfer and C-alkylation. Mo-based POMs represent a versatile catalytic platform to simultaneously upgrade lignin-derived oxygenated aromatics into alkylated arenes. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

40 CFR 721.5985 - Fatty alkyl phosphate, alkali metal salt (generic).

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Fatty alkyl phosphate, alkali metal... Specific Chemical Substances § 721.5985 Fatty alkyl phosphate, alkali metal salt (generic). (a) Chemical... as a fatty alkyl phosphate, alkali metal salt (PMN P-99-0385) is subject to reporting under this...

40 CFR 721.5985 - Fatty alkyl phosphate, alkali metal salt (generic).

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Fatty alkyl phosphate, alkali metal... Specific Chemical Substances § 721.5985 Fatty alkyl phosphate, alkali metal salt (generic). (a) Chemical... as a fatty alkyl phosphate, alkali metal salt (PMN P-99-0385) is subject to reporting under this...

40 CFR 721.2094 - N,N′-di(alkyl heteromonocycle)amino chlorotriazine.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 31 2011-07-01 2011-07-01 false N,Nâ²-di(alkyl heteromonocycle)amino... Specific Chemical Substances § 721.2094 N,N′-di(alkyl heteromonocycle)amino chlorotriazine. (a) Chemical... as N,N′-di(alkyl heteromonocycle)amino chlorotriazine (PMN P-93-1369) is subject to reporting under...

40 CFR 721.2094 - N,N′-di(alkyl heteromonocycle)amino chlorotriazine.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false N,Nâ²-di(alkyl heteromonocycle)amino... Specific Chemical Substances § 721.2094 N,N′-di(alkyl heteromonocycle)amino chlorotriazine. (a) Chemical... as N,N′-di(alkyl heteromonocycle)amino chlorotriazine (PMN P-93-1369) is subject to reporting under...

Alanine synthesis from glyceraldehyde and ammonium ion in aqueous solution

NASA Technical Reports Server (NTRS)

Weber, A. L.

1985-01-01

The formation of alanine (ala) form C(14)-glyceraldehyde and ammonium phosphate in the presence or absence of a thiol is reported. At ambient temperature, ala synthesis was six times more rapid in the presence of 3-mercaptopropionic acid than in its absence (0.6 and 0.1 percent, respectively, after 60 days). Similarly, the presence of another thiol, N-acetylcysteinate, increased the production of ala, as well as of lactate. The reaction pathway of thiol-catalyzed synthesis of ala, with the lactic acid formed in a bypath, is suggested. In this, dehydration of glyceraldehyde is followed by the formation of hemithioacetal. In the presence of ammonia, an imine is formed, which eventually yields ala. This pathway is consistent with the observation that the rate ratio of ala/lactate remains constant throughout the process. The fact that the reaction takes place under anaerobic conditions in the presence of H2O and with the low concentrations of simple substrates and catalysts makes it an attractive model prebiotic reaction in the process of molecular evolution.

40 CFR 721.520 - Alanine, N-(2-carboxyethyl)-N-alkyl-, salt.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Alanine, N-(2-carboxyethyl)-N-alkyl... Specific Chemical Substances § 721.520 Alanine, N-(2-carboxyethyl)-N-alkyl-, salt. (a) Chemical substance... alanine, N-(2-carboxyethyl)-N- alkyl-, salt (P-89-336) is subject to reporting under this section for the...

40 CFR 721.520 - Alanine, N-(2-carboxyethyl)-N-alkyl-, salt.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Alanine, N-(2-carboxyethyl)-N-alkyl... Specific Chemical Substances § 721.520 Alanine, N-(2-carboxyethyl)-N-alkyl-, salt. (a) Chemical substance... alanine, N-(2-carboxyethyl)-N- alkyl-, salt (P-89-336) is subject to reporting under this section for the...

System Response of Metabolic Networks in Chlamydomonas reinhardtii to Total Available Ammonium

PubMed Central

Lee, Do Yup; Park, Jeong-Jin; Barupal, Dinesh K.; Fiehn, Oliver

2012-01-01

Drastic alterations in macronutrients are known to cause large changes in biochemistry and gene expression in the photosynthetic alga Chlamydomonas reinhardtii. However, metabolomic and proteomic responses to subtle reductions in macronutrients have not yet been studied. When ammonium levels were reduced by 25–100% compared with control cultures, ammonium uptake and growth rates were not affected at 25% or 50% nitrogen-reduction for 28 h. However, primary metabolism and enzyme expression showed remarkable changes at acute conditions (4 h and 10 h after ammonium reduction) compared with chronic conditions (18 h and 28 h time points). Responses of 145 identified metabolites were quantified using gas chromatography-time of flight mass spectrometry; 495 proteins (including 187 enzymes) were monitored using liquid chromatography-ion trap mass spectrometry with label-free spectral counting. Stress response and carbon assimilation processes (Calvin cycle, acetate uptake and chlorophyll biosynthesis) were altered first, in addition to increase in enzyme contents for lipid biosynthesis and accumulation of short chain free fatty acids. Nitrogen/carbon balance metabolism was found changed only under chronic conditions, for example in the citric acid cycle and amino acid metabolism. Metabolism in Chlamydomonas readily responds to total available media nitrogen with temporal increases in short-chain free fatty acids and turnover of internal proteins, long before nitrogen resources are depleted. PMID:22787274

Membrane potential independent transport of NH3 in the absence of ammonium permeases in Saccharomyces cerevisiae.

PubMed

Cueto-Rojas, Hugo F; Milne, Nicholas; van Helmond, Ward; Pieterse, Mervin M; van Maris, Antonius J A; Daran, Jean-Marc; Wahl, S Aljoscha

2017-04-17

Microbial production of nitrogen containing compounds requires a high uptake flux and assimilation of the N-source (commonly ammonium), which is generally coupled with ATP consumption and negatively influences the product yield. In the industrial workhorse Saccharomyces cerevisiae, ammonium (NH 4 + ) uptake is facilitated by ammonium permeases (Mep1, Mep2 and Mep3), which transport the NH 4 + ion, resulting in ATP expenditure to maintain the intracellular charge balance and pH by proton export using the plasma membrane-bound H + -ATPase. To decrease the ATP costs for nitrogen assimilation, the Mep genes were removed, resulting in a strain unable to uptake the NH 4 + ion. Subsequent analysis revealed that growth of this ∆mep strain was dependent on the extracellular NH 3 concentrations. Metabolomic analysis revealed a significantly higher intracellular NH X concentration (3.3-fold) in the ∆mep strain than in the reference strain. Further proteomic analysis revealed significant up-regulation of vacuolar proteases and genes involved in various stress responses. Our results suggest that the uncharged species, NH 3 , is able to diffuse into the cell. The measured intracellular/extracellular NH X ratios under aerobic nitrogen-limiting conditions were consistent with this hypothesis when NH x compartmentalization was considered. On the other hand, proteomic analysis indicated a more pronounced N-starvation stress response in the ∆mep strain than in the reference strain, which suggests that the lower biomass yield of the ∆mep strain was related to higher turnover rates of biomass components.

Ammonium Metabolism Enzymes Aid Helicobacter pylori Acid Resistance

PubMed Central

Miller, Erica F.

2014-01-01

The gastric pathogen Helicobacter pylori possesses a highly active urease to support acid tolerance. Urea hydrolysis occurs inside the cytoplasm, resulting in the production of NH3 that is immediately protonated to form NH4+. This ammonium must be metabolized or effluxed because its presence within the cell is counterproductive to the goal of raising pH while maintaining a viable proton motive force (PMF). Two compatible hypotheses for mitigating intracellular ammonium toxicity include (i) the exit of protonated ammonium outward via the UreI permease, which was shown to facilitate diffusion of both urea and ammonium, and/or (ii) the assimilation of this ammonium, which is supported by evidence that H. pylori assimilates urea nitrogen into its amino acid pools. We investigated the second hypothesis by constructing strains with altered expression of the ammonium-assimilating enzymes glutamine synthetase (GS) and glutamate dehydrogenase (GDH) and the ammonium-evolving periplasmic enzymes glutaminase (Ggt) and asparaginase (AsnB). H. pylori strains expressing elevated levels of either GS or GDH are more acid tolerant than the wild type, exhibit enhanced ammonium production, and are able to alkalize the medium faster than the wild type. Strains lacking the genes for either Ggt or AsnB are acid sensitive, have 8-fold-lower urea-dependent ammonium production, and are more acid sensitive than the parent. Additionally, we found that purified H. pylori GS produces glutamine in the presence of Mg2+ at a rate similar to that of unadenylated Escherichia coli GS. These data reveal that all four enzymes contribute to whole-cell acid resistance in H. pylori and are likely important for assimilation and/or efflux of urea-derived ammonium. PMID:24936052

40 CFR 721.644 - Amines, C12-14-tert-alkyl, sulfonates.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Amines, C12-14-tert-alkyl, sulfonates... Substances § 721.644 Amines, C12-14-tert-alkyl, sulfonates. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as amines, C12-14-tert-alkyl, sulfonates (PMN...

40 CFR 721.644 - Amines, C12-14-tert-alkyl, sulfonates.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Amines, C12-14-tert-alkyl, sulfonates... Substances § 721.644 Amines, C12-14-tert-alkyl, sulfonates. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as amines, C12-14-tert-alkyl, sulfonates (PMN...

Structuring of Amide Cross-Linked Non-Bridged and Bridged Alkyl-Based Silsesquioxanes.

PubMed

Nunes, S C; de Zea Bermudez, V

2018-02-06

The development of sophisticated organized materials exhibiting enhanced properties is a challenging topic of the domain of organic/inorganic hybrid materials. This review, composed of four sections, reports the work we have carried out over the last 10 years on the synthesis of amide cross-linked alkyl/siloxane hybrids by means of sol-gel chemistry and self-directed assembly/self-organization routes relying on weak interactions (hydrophobic interactions and hydrogen bonding). The various as-produced lamellar structures displaying a myriad of morphologies, often closely resembling those found in natural materials, are discussed. The major role played by the synthetic conditions (pH, water content, co-solvent(s) nature/concentration and dopant presence/concentration), the alkyl chains (length and presence of ramification or not) and the number of the amide cross-links present in the precursor, is evidenced. Examples of highly organized hybrids structures incorporating ionic species (alkali and alkaline earth metal salts) and optically-active centers (organic dyes and lanthanide ions) are described. A useful qualitative relationship deduced between the emission quantum yield of the ordered hybrid materials and the degree of order of the hydrogen-bonded network is highlighted. © 2018 The Chemical Society of Japan & Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Synthesis of D-glucosamine quaternary ammonium derivatives and evaluation of their antifungal activity together with aminodeoxyglucose derivatives against two wood fungi Coriolus versicolor and Poria placenta: structure-activity relationships.

PubMed

Muhizi, Théoneste; Coma, Véronique; Grelier, Stéphane

2011-03-01

Structure-activity relationships are often reported in scientific studies. These may be employed in searching for new acceptable biocides to use against harmful microorganisms, because the biocides used hitherto encounter various problems, including lack of efficiency, high toxicity and persistence. Nowadays, scientists are trying to find new, environmentally acceptable biocides to replace these earlier biocides. Different compounds from renewable materials have been studied and have shown pronounced antifungal activity against wood fungi. These include aminopolysaccharide derivatives and different quaternary ammonium polymers. A biological study carried out with these products indicated a possible relationship between amino groups and differences in biological activity observed. In this study, an amino group was successively fixed to different carbon atoms of glucose, and glucosamine was also modified by both N-alkylation and quaternisation. The impact of the amino group position on antifungal activity against two wood decay fungi was investigated. The amino group at the anomeric position showed the highest antifungal activity against both Coriolus versicolor Quel. and Poria placenta (Fr.) Cooke. Furthermore, the positive impact of both N-alkylation and quaternisation on the growth of both strains was demonstrated. The anomeric position of the amino group and the N-alkylation and quaternisation of amino sugars considerably increase the antifungal activity of these compounds. Copyright © 2010 Society of Chemical Industry.

Calcium sulphate in ammonium sulphate solution

USGS Publications Warehouse

Sullivan, E.C.

1905-01-01

Calcium sulphate, at 25?? C., is two-thirds as soluble in dilute (o.i mol per liter) and twice as soluble in concentrated (3 mois per liter) ammonium sulphate solution as in water. The specific electric conductivity of concentrated ammonium sulphate solutions is lessened by saturating with calcium sulphate. Assuming that dissociation of ammonium sulphate takes place into 2NH4?? and SO4" and of calcium sulphate into Ca and SO4" only, and that the conductivity is a measure of such dissociation, the solubility of calcium sulphate in dilute ammonium sulphate solutions is greater than required by the mass-law. The conductivity of the dilute mixtures may be accurately calculated by means of Arrhenius' principle of isohydric solutions. In the data obtained in these calculations, the concentration of non-dissociated calcium sulphate decreases with increasing ammonium sulphate. The work as a whole is additional evidence of the fact that we are not yet in possession of all the factors necessary for reconciling the mass-law to the behavior of electrolytes. The measurements above described were made in the chemical laboratory of the University of Michigan.

Infrared spectra of the ammonium ion in ammonium hexavanadate (NH 4) 2V 6O 16

NASA Astrophysics Data System (ADS)

de Waal, D.; Heyns, A. M.; Range, K.-J.; Eglmeier, C.

The infrared bands of the NH +4 and ND +4 groups in (NH 4) 2V 6O 16 and its deuterated analogue can be assigned with a fair amount of certainty at 90 K under the space group P2 1/ m( C22 h). The ND stretching modes of isotopically dilute NH 3D + ions in the crystal are in agreement with the predicted splitting into Cs, Cs and C1(2) components. The frequencies, shapes and temperature dependence of these modes suggest that both normal and bifurcated hydrogen bonds are formed. The latter closely resembles corresponding bonds in NH 4VO 3, but the normal hydrogen bonds are not as strong as the similar bonds in NH 4VO 3. This can be expected as NH +4 ions are dynamic in character in (NH 4) 2V 6O 16 and remain so down to temperatures of 90 K.

On the influence of ion exchange on the local structure of the titanosilicate ETS-10.

PubMed

Pavel, Claudiu C; Zibrowius, Bodo; Löffler, Elke; Schmidt, Wolfgang

2007-07-14

The effect of ion exchange with different monovalent cations (NH(4)(+), K(+), Na(+) and Cs(+)) on the local structure of the titanosilicate ETS-10 has been studied by (29)Si MAS NMR and Raman spectroscopy. Although X-ray diffraction shows no significant influence of ion exchange on the long range order, ammonium exchange is found to result in substantial damage to the local structure. Ion exchange experiments with alkali cations under significantly more acidic conditions clearly show that the structural damage brought about by ammonium exchange is not caused by the low pH of the exchange solution. The exchange with potassium and caesium ions also leads to significant changes in the (29)Si NMR and Raman spectra. However, these changes can largely be reversed by sodium back-exchange.

Alkylation sensitivity screens reveal a conserved cross-species functionome

PubMed Central

Svilar, David; Dyavaiah, Madhu; Brown, Ashley R.; Tang, Jiang-bo; Li, Jianfeng; McDonald, Peter R.; Shun, Tong Ying; Braganza, Andrea; Wang, Xiao-hong; Maniar, Salony; St Croix, Claudette M.; Lazo, John S.; Pollack, Ian F.; Begley, Thomas J.; Sobol, Robert W.

2013-01-01

To identify genes that contribute to chemotherapy resistance in glioblastoma, we conducted a synthetic lethal screen in a chemotherapy-resistant glioblastoma derived cell line with the clinical alkylator temozolomide (TMZ) and an siRNA library tailored towards “druggable” targets. Select DNA repair genes in the screen were validated independently, confirming the DNA glycosylases UNG and MYH as well as MPG to be involved in the response to high dose TMZ. The involvement of UNG and MYH is likely the result of a TMZ-induced burst of reactive oxygen species. We then compared the human TMZ sensitizing genes identified in our screen with those previously identified from alkylator screens conducted in E. coli and S. cerevisiae. The conserved biological processes across all three species composes an Alkylation Functionome that includes many novel proteins not previously thought to impact alkylator resistance. This high-throughput screen, validation and cross-species analysis was then followed by a mechanistic analysis of two essential nodes: base excision repair (BER) DNA glycosylases (UNG, human and mag1, S. cerevisiae) and protein modification systems, including UBE3B and ICMT in human cells or pby1, lip22, stp22 and aim22 in S. cerevisiae. The conserved processes of BER and protein modification were dual targeted and yielded additive sensitization to alkylators in S. cerevisiae. In contrast, dual targeting of BER and protein modification genes in human cells did not increase sensitivity, suggesting an epistatic relationship. Importantly, these studies provide potential new targets to overcome alkylating agent resistance. PMID:23038810

Regulation of DNA Alkylation Damage Repair: Lessons and Therapeutic Opportunities

PubMed Central

Soll, Jennifer M.; Sobol, Robert W.; Mosammaparast, Nima

2016-01-01

Alkylation chemotherapy is one of the most widely used systemic therapies for cancer. While somewhat effective, clinical responses and toxicities of these agents are highly variable. A major contributing factor for this variability is the numerous distinct lesions that are created upon alkylation damage. These adducts activate multiple repair pathways. There is mounting evidence that the individual pathways function cooperatively, suggesting that coordinated regulation of alkylation repair is critical to prevent toxicity. Furthermore, some alkylating agents produce adducts that overlap with newly discovered methylation marks, making it difficult to distinguish between bona fide damaged bases and so called ‘epigenetic’ adducts. We discuss new efforts aimed at deciphering the mechanisms that regulate these repair pathways, emphasizing their implications for cancer chemotherapy. PMID:27816326

Ammonium sulfamate

Integrated Risk Information System (IRIS)

Ammonium sulfamate ; CASRN 7773 - 06 - 0 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogen

Ammonium acetate

Integrated Risk Information System (IRIS)

Ammonium acetate ; CASRN 631 - 61 - 8 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic

Ammonium methacrylate

Integrated Risk Information System (IRIS)

Ammonium methacrylate ; CASRN 16325 - 47 - 6 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcin

Palladium-catalyzed Heck-type cross-couplings of unactivated alkyl iodides.

PubMed

McMahon, Caitlin M; Alexanian, Erik J

2014-06-02

A palladium-catalyzed, intermolecular Heck-type coupling of alkyl iodides and alkenes is described. This process is successful with a variety of primary and secondary unactivated alkyl iodides as reaction partners, including those with hydrogen atoms in the β position. The mild catalytic conditions enable intermolecular C-C bond formations with a diverse set of alkyl iodides and alkenes, including substrates containing base- or nucleophile-sensitive functionality. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A fast, reliable, ultra high performance liquid chromatography method for the simultaneous determination of amino acids, biogenic amines and ammonium ions in cheese, using diethyl ethoxymethylenemalonate as a derivatising agent.

PubMed

Redruello, Begoña; Ladero, Victor; Cuesta, Isabel; Álvarez-Buylla, Jorge R; Martín, María Cruz; Fernández, María; Alvarez, Miguel A

2013-08-15

Derivatisation treatment with diethyl ethoxymethylenemalonate followed by ultra-HPLC allowed the simultaneous quantification of 22 amino acids, 7 biogenic amines and ammonium ions in cheese samples in under 10 min. This is the fastest elution time ever reported for such a resolution. The proposed method shows good linearity (R(2)>0.995) and sensitivity (detection limit 0.08-3.91 μM; quantification limit <13.02 μM). Intra- and inter-day repeatability ranged from 0.35% to 1.25% and from 0.85% to 5.2%, respectively. No significant effect of the cheese matrix was observed. Copyright © 2013 Elsevier Ltd. All rights reserved.

78 FR 32690 - Certain Ammonium Nitrate From Ukraine

Federal Register 2010, 2011, 2012, 2013, 2014

2013-05-31

... INTERNATIONAL TRADE COMMISSION [Investigation No. 731-TA-894 (Review)] Certain Ammonium Nitrate... certain ammonium nitrate from Ukraine would be likely to lead to continuation or recurrence of material... Ammonium Nitrate from Ukraine: Investigation No. 731-TA-894 (Second Review). By order of the Commission...

Chiral Alkyl Halides: Underexplored Motifs in Medicine

PubMed Central

Gál, Bálint; Bucher, Cyril; Burns, Noah Z.

2016-01-01

While alkyl halides are valuable intermediates in synthetic organic chemistry, their use as bioactive motifs in drug discovery and medicinal chemistry is rare in comparison. This is likely attributable to the common misconception that these compounds are merely non-specific alkylators in biological systems. A number of chlorinated compounds in the pharmaceutical and food industries, as well as a growing number of halogenated marine natural products showing unique bioactivity, illustrate the role that chiral alkyl halides can play in drug discovery. Through a series of case studies, we demonstrate in this review that these motifs can indeed be stable under physiological conditions, and that halogenation can enhance bioactivity through both steric and electronic effects. Our hope is that, by placing such compounds in the minds of the chemical community, they may gain more traction in drug discovery and inspire more synthetic chemists to develop methods for selective halogenation. PMID:27827902

Segregation in like-charged polyelectrolyte-surfactant mixtures can be precisely tuned via manipulation of the surfactant mass ratio.

PubMed