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Sample records for carboxylic acid salts

  1. Production of carboxylic acid and salt co-products

    Science.gov (United States)

    Hanchar, Robert J.; Kleff, Susanne; Guettler, Michael V.

    2014-09-09

    This invention provide processes for producing carboxylic acid product, along with useful salts. The carboxylic acid product that is produced according to this invention is preferably a C.sub.2-C.sub.12 carboxylic acid. Among the salts produced in the process of the invention are ammonium salts.

  2. 40 CFR 721.4663 - Fluorinated carboxylic acid alkali metal salts.

    Science.gov (United States)

    2010-07-01

    ... Specific Chemical Substances § 721.4663 Fluorinated carboxylic acid alkali metal salts. (a) Chemical... fluorinated carboxylic acid alkali metal salts (PMNs P-95-979/980/981) are subject to reporting under this... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Fluorinated carboxylic acid alkali...

  3. Impact of the counterion on the solubility and physicochemical properties of salts of carboxylic acid drugs.

    Science.gov (United States)

    David, S E; Timmins, P; Conway, B R

    2012-01-01

    Salt formation is a widely used approach to improve the physicochemical and solid state properties of an active pharmaceutical ingredient. In order to better understand the relationships between the active drug, the selected counterion and the resultant salt form, crystalline salts were formed using four different carboxylic acid drugs and a closely related series of amine counterions. Thirty-six related crystalline salts were prepared, characterized and the relationship between solubility and dissolution behaviour and other properties of the salt and the counterion studied. Salts of four model acid drugs, gemfibrozil, flurbiprofen, ibuprofen and etodolac were prepared using the counterions butylamine, hexylamine, octylamine, benzylamine, cyclohexylamine, tert-butylamine, 2-amino-2-methylpropan-1-ol, 2-amino-2-methylpropan-1,3-diol and tris(hydroxymethyl)aminomethane. Salt formation was confirmed, the salts were characterized and their corresponding solubilities determined and rationalized with respect to the counterions' properties. The properties of the salt highly dependent on the nature of the counterion and, although there is considerable variation, some general conclusion can be drawn. For the alkyl amines series, increasing chain length leads to a reduction in solubility across all the acidic drugs studied and a reduction in melting point, thus contradicting simplistic relationships between solubility and melting point. Small, compact counterions consistently produce crystalline salts with high melting point accompanied with a modest improvement in solubility and the nature of hydrogen bonding between the ions has a major impact on the solubility.

  4. Structure of eight molecular salts assembled from noncovalent bonding between carboxylic acids, imidazole, and benzimidazole

    Science.gov (United States)

    Jin, Shouwen; Zhang, Huan; Liu, Hui; Wen, Xianhong; Li, Minghui; Wang, Daqi

    2015-09-01

    Eight organic salts of imidazole/benzimidazole have been prepared with carboxylic acids as 2-methyl-2-phenoxypropanoic acid, α-ketoglutaric acid, 5-nitrosalicylic acid, isophthalic acid, 4-nitro-phthalic acid, and 3,5-dinitrosalicylic acid. The eight crystalline forms reported are proton-transfer compounds of which the crystals and compounds were characterized by X-ray diffraction analysis, IR, mp, and elemental analysis. These structures adopted hetero supramolecular synthons, with the most common R22(7) motif observed at salts 2, 3, 5, 6 and 8. Analysis of the crystal packing of 1-8 suggests that there are extensive strong Nsbnd H⋯O, and Osbnd H⋯O hydrogen bonds (charge assisted or neutral) between acid and imidazolyl components in all of the salts. Except the classical hydrogen bonding interactions, the secondary propagating interactions also play important roles in structure extension. This variety, coupled with the varying geometries and number of acidic groups of the acids utilized, has led to the creation of eight supramolecular arrays with 1D-3D structure. The role of weak and strong noncovalent interactions in the crystal packing is analyzed. The results presented herein indicate that the strength and directionality of the Nsbnd H⋯O, and Osbnd H⋯O hydrogen bonds between acids and imidazole/benzimidazole are sufficient to bring about the formation of organic salts.

  5. New co-crystal and salt form of sulfathiazole with carboxylic acid and ...

    Indian Academy of Sciences (India)

    e-mail: cmallareddy@gmail.com. MS received 14 May 2014; revised 8 July 2014; accepted 8 July 2014. Abstract. One co-crystal and one salt of an antibacterial drug sulfathiazole with 4-aminobenzamide and 2,4- dinitrobenzoic acid have been synthesized. These new forms are characterized by single crystal X-ray diffrac-.

  6. Volatility of atmospherically relevant alkylaminium carboxylate salts.

    Science.gov (United States)

    Lavi, Avi; Segre, Enrico; Gomez-Hernandez, Mario; Zhang, Renyi; Rudich, Yinon

    2015-05-14

    Heterogeneous neutralization reactions of ammonia and alkylamines with sulfuric acid play an important role in aerosol formation and particle growth. However, little is known about the physical and chemical properties of alkylaminium salts of organic acids. In this work we studied the thermal stability and volatility of alkylaminium carboxylate salts of short aliphatic alkylamines with monocarboxylic and dicarboxylic acids. The enthalpy of vaporization and saturation vapor pressure at 298 K were derived using the kinetic model of evaporation and the Clausius-Clapeyron relation. The vapor pressure of alkylaminium dicarboxylate salts is ∼10(-6) Pa, and the vaporization enthalpy ranges from 73 to 134 kJ mol(-1). Alkylaminium monocarboxylate salts show high thermal stability, and their thermograms do not follow our evaporation model. Hence, we inferred their vapor pressure from their thermograms as comparable to that of ammonium sulfate (∼10(-9) Pa). Further characterization showed that alkylaminium monocarboxylates are room temperature protic ionic liquids (RTPILs) that are more hygroscopic than ammonium sulfate (AS). We suggest that the irregular thermograms result from an incomplete neutralization reaction leading to a mixture of ionic and nonionic compounds. We conclude that these salts are expected to contribute to new particle formation and particle growth under ambient conditions and can significantly enhance the CCN activity of mixed particles in areas where SO2 emissions are regulated.

  7. Crystal and molecular structures of sixteen charge-assisted hydrogen bond-mediated diisopropylammonium salts from different carboxylic acids

    Science.gov (United States)

    Lin, Zhihao; Hu, Kaikai; Jin, Shouwen; Ding, Aihua; Wang, Yining; Dong, Lingfeng; Gao, Xingjun; Wang, Daqi

    2017-10-01

    Cocrystallization of the commonly available organic amine, diisopropylamine, with a series of carboxylic acids gave a total of sixteen molecular salts with the compositions: diisopropylaminium 2-methyl-2-phenoxypropanate [(Hdpa)+ · (mpa-), mpa- = 2-methyl-2-phenoxypropanoate] (1), diisopropylaminium 2-methyl-2-(naphthalen-2-yloxy)-propionate [(Hdpa)+ · (npa-), npa- = 2-methyl-2-(naphthalen-2-yloxy)-propionate] (2), diisopropylaminium indole-3-acetate [(Hdpa)+ · (iaa-), iaa- = indole-3-acetate] (3), diisopropylaminium 4-chlorophenoxyacetate [(Hdpa)+ · (cpa-), cpa- = 4-chlorophenoxyacetate] (4), diisopropylaminium 2,4-dichlorophenoxyacetate [(Hdpa)+ · (dcpa-), dcpa- = 2,4-dichlorophenoxyacetate] (5), diisopropylaminium 4-hydroxybenzoate [(Hdpa)+ · (hba-), hba- = 4-hydroxybenzoate] (6), diisopropylaminium 4-aminobenzoate [(Hdpa)+ · (aba-), aba- = 4-aminobenzoate] (7), tetra(diisopropylaminium) tetra(1-hydroxy-2-naphthoate) trihydrate [(Hdpa)44+ · (2-hnpa)44- · 3H2O, 2-hnpa = 1-hydroxy-2-naphthoate] (8), diisopropylaminium 2-hydroxy-3-naphthoate [(Hdpa)+ · (3-hnpa-), 3-hnpa- = 2-hydroxy-3-naphthoate] (9), diisopropylaminium 5-bromosalicylate [(Hdpa)+ · (bsa-), bsa- = 5-bromosalicylate] (10), diisopropylaminium 3,5-dinitrobenzoate [(Hdpa)+ · (dna-), dna- = 3,5-dinitrobenzoate] (11), diisopropylaminium 3,5-dinitrosalicylate [(Hdpa)+ · (3,5-dns-), 3,5-dns- = 3,5-dinitrosalicylate] (12), tetra(diisopropylaminium) bis(m-phthalate) monohydrate [(Hdpa+)4 · (mpta2-)2 · H2O, mpta2- = m-phthalate] (13), bis(diisopropylaminium) dihydrogen 1,2,3,4-butane tetracarboxylate [(Hdpa+)2 · (H2Bta2-), H2Bta2- = dihydrogen 1,2,3,4-butane tetracarboxylate] (14), bis(diisopropylaminium) mucate [(Hdpa+)2 · (muc2-), muc2- = mucate] (15), and diisopropylaminium hydrogen 1,2-phenylenediacetate [(Hdpa) · (Hpda-), Hpda- = hydrogen 1,2-phenylenediacetate] (16). The sixteen salts have been characterised by XRD technique, IR, and elemental analysis, and the melting points of all the

  8. Metal extraction by amides of carboxylic acids

    International Nuclear Information System (INIS)

    Skorovarov, D.I.; Chumakova, G.M.; Rusin, L.I.; Ul'anov, V.S.; Sviridova, R.A.; Sviridov, A.L.

    1988-01-01

    Extraction ability of various amides was studied. Data on extraction of rare earths, vanadium, molybdenum, rhenium, uranium, niobium, tantalum by N,N-dibutyl-amides of acetic, nonanic acids and fatly synthetic acids of C 7 -C 9 fractions are presented. Effect of salting-out agents, inorganic acid concentrations on extraction process was studied. Potential ability of using amides of carboxylic acids for extractional concentration of rare earths as well as for recovery and separation of iron, rhenium, vanadium, molybdenum, uranium, niobium, and tantalum was shown

  9. Carboxylic acid exchangers in analytical chemistry

    International Nuclear Information System (INIS)

    Venkateswarlu, Ch.

    1976-01-01

    The literature on the use of carboxylic acid exchangers in inorganic analytical chemistry is reviewed. It is classified under two heads, based on the ionic form in which the exchanger is employed, viz., the salt form and the acid form. In the salt form, the separations reported in the beginning are mostly carried out in alkaline medium, employing ammonia and its derivatives as complexing agents to hold cations in solution. This was followed by the use of ammonium ion as an eluent from heavy weakly or neutral solutions. There are a few separations reported making use of EDTA as eluent. It appears that separation of some anions from cations can be achieved with greater ease with these exchangers than with sulphonic acid type. Contary to the general belief, carboxylic acid exchangers are used in H + form to achieve some analytical separations of cations of interest. These exchangers exhibit better sorption of some cations in presence of complexing agents containing basic nitrogen as a donor. In fact, a careful study of these exchangers with different matrices might yield really selective exchangers, than the chelating ones known commercially. From the separation cited, carboxylic acid exchangers appear to have greater potentialities in their applications, than what is normally expected. (author)

  10. Design of co-crystals/salts of some Nitrogenous bases and some derivatives of thiophene carboxylic acids through a combination of hydrogen and halogen bonds.

    Science.gov (United States)

    Jennifer, Samson Jegan; Muthiah, Packianathan Thomas

    2014-01-01

    The utility of N-heterocyclic bases to obtain molecular complexes with carboxylic acids is well studied. Depending on the solid state interaction between the N-heterocyclic base and a carboxylic acid a variety of neutral or ionic synthons are observed. Meanwhile, pyridines and pyrimidines have been frequently chosen in the area of crystal engineering for their multipurpose functionality. HT (hetero trimers) and LHT (linear heterotetramers) are the well known synthons that are formed in the presence of pyrimidines and carboxylic acids. Fourteen crystals involving various substituted thiophene carboxylic acid derivatives and nitrogenous bases were prepared and characterized by using single crystal X-ray diffraction. The 14 crystals can further be divided into two groups [1a-7a], [8b-14b] based on the nature of the nitrogenous base. Carboxylic acid to pyridine proton transfer has occurred in 3 compounds of each group. In addition to the commonly occurring hydrogen bond based pyridine/carboxylic acid and pyrimidine/carboxylic acid synthons which is the reason for assembly of primary motifs, various other interactions like Cl…Cl, Cl…O, C-H…Cl, C-H…S add additional support in organizing these supermolecules into extended architectures. It is also interesting to note that in all the compounds π-π stacking occurs between the pyrimidine-pyrimidine or pyridine-pyridine or acid-acid moieties rather than acid-pyrimidine/pyridine. In all the compounds (1a-14b) either neutral O-H…Npyridyl/pyrimidine or charge-assisted Npyridinium-H…Ocarboxylate hydrogen bonds are present. The HT (hetero trimers) and LHT (linear heterotetramers) are dominant in the crystal structures of the adducts containing N-heterocyclic bases with two proton acceptors (1a-7a). Similar type supramolecular ladders are observed in 5TPC44BIPY (8b), TPC44BIPY (9b), TPC44TMBP (11b). Among the seven compounds [8b-14b] the extended ligands are linear in all except for the TMBP (10b, 11b, 12b). The

  11. Kinetics study of thermal decomposition of calcium carboxylate salts

    International Nuclear Information System (INIS)

    Landoll, Michael P.; Holtzapple, Mark T.

    2013-01-01

    The MixAlco™ process ferments lignocellulosic biomass to carboxylate salts that are thermally decomposed into ketones, which are then chemically converted to a wide variety of chemicals and fuels. To perform these decompositions, suitable reaction models are necessary to properly design, scale, and optimize commercial reactors. For three salt types (calcium acetate, and two types of mixed calcium carboxylate salts), activation energy was determined using three isoconversional methods that employed TGA curves at different heating rates. For all three salt types, activation energy varied significantly with conversion. The average activation energy for calcium acetate was 556.75 kJ mol −1 , and the activation energies for the two mixed calcium carboxylate salts were 232.87, and 176.55 kJ mol −1 . In addition, three functions of conversion were employed to see which one best modeled the experimental data. The Sestak–Berggren model provides the best universal fit for all three salt types. -- Highlights: •Calcium carboxylate salts from fermentation broth thermally decompose to ketones. •Activation energy varies with conversion for all three salt types. •Sestak–Berggren model provides best fit overall for all three salt types

  12. Kinetics study of thermal decomposition of sodium carboxylate salts

    International Nuclear Information System (INIS)

    Landoll, Michael P.; Holtzapple, Mark T.

    2012-01-01

    The MixAlco™ process ferments lignocellulosic biomass to carboxylate salts that are thermally decomposed into ketones, which are then chemically converted to a wide variety of chemicals and fuels. To perform these decompositions, suitable reaction models are necessary to properly design, scale, and optimize commercial reactors. For three salt types (sodium acetate, and two types of mixed sodium carboxylate salts), activation energy was determined using three isoconversional methods that employed TGA curves at different heating rates. For all three salt types, activation energy varied significantly with conversion. The average activation energy for sodium acetate was 226.65 kJ/mol, and the activation energies for the two mixed sodium carboxylate salts were 195.61, and 218.18 kJ/mol. In addition, three functions of conversion were employed to see which one best modeled the experimental data. The Sestak-Berggren model fits all three salt types best. -- Highlights: ► Sodium carboxylate salts from fermentation broth thermally decompose to ketones. ► Activation energy varies with conversion for all three salt types. ► Sestak-Berggren model provides best fit for all three salt types.

  13. Triboelectrification of active pharmaceutical ingredients: week acids and their salts.

    Science.gov (United States)

    Fujinuma, Kenta; Ishii, Yuji; Yashihashi, Yasuo; Yonemochi, Estuo; Sugano, Kiyohiko; Tarada, Katsuhide

    2015-09-30

    The effect of salt formulation on the electrostatic property of active pharmaceutical ingredients was investigated. The electrostatic property of weak acids (carboxylic acids and amide-enole type acid) and their sodium salts was evaluated by a suction-type Faraday cage meter. Free carboxylic acids showed negative chargeability, whereas their sodium salts showed more positive chargeability than the free acids. However, no such trend was observed for amide-enole type acids. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. IR, FT-ICR-MS studies on (1'S, 6'S)-1-cyclopropyl-7-(2,8-diazabicyclo[4.3.0] non-8-yl)-6-fluoro-8-methoxy-4-oxo-1,4-dihydroquinoline-3-carboxylic acid hydrochloride salt.

    Science.gov (United States)

    Lin, Zhiwei

    2014-01-01

    The infrared spectra of (1'S, 6'S)-1-cyclopropyl-7-(2,8-diazabicyclo[4.3.0] non-8-yl)-6-fluoro-8-methoxy-4-oxo-1,4-dihydroquinoline-3-carboxylic acid hydrochloride salt (CLF-HCl) were studied and compared with free base. Their fragmentation pathways were investigated using tandem mass spectrometric (MS/MS) techniques on Fourier-transform ion cyclotron resonance spectrum, and many characteristic fragment ions were found. Copyright © 2013 Elsevier B.V. All rights reserved.

  15. Decarboxylative Trifluoromethylation of Aliphatic Carboxylic Acids.

    Science.gov (United States)

    Kautzky, Jacob A; Wang, Tao; Evans, Ryan W; MacMillan, David W C

    2018-05-14

    Herein we disclose an efficient method for the conversion of carboxylic acids to trifluoromethyl groups via the combination of photoredox and copper catalysis. This transformation tolerates a wide range of functionality including heterocycles, olefins, alcohols, and strained ring systems. To demonstrate the broad potential of this new methodology for late-stage functionalization, we successfully converted a diverse array of carboxylic acid-bearing natural products and medicinal agents to the corresponding trifluoromethyl analogues.

  16. CARBOXYLIC ACIDS ELECTROOXIDATION ON SHUNGITE ELECTRODE

    Directory of Open Access Journals (Sweden)

    Oleksandr Davydenko

    2017-03-01

    Full Text Available Purpose: This article discusses the electrochemical method of directional conversion of carboxylic acids, which are the most aggressive hydrocarbons oxidation products back into the corresponding hydrocarbons. Existing methods for the regeneration of waste petroleum oils have significant drawbacks, which include the formation of new hard-reclaimed waste and loss of a significant part of the oil during regeneration. Methods: Electrooxidation processes of carboxylic acid on various electrode materials: platinum, graphite and shungite anodes were studied. Results: Potentiostatic polarization curves with simultaneous measurement of near-electrode solution pH showed differences in the process on these anode materials: dimer yield for Kolbe is decreased under the transition from platinum to shungite. At potentials higher than 2.0 v, carboxylic acid has a higher adsorbability compared to water. Therefore Faraday’s side-process of water oxidation doesn’t almost occur, which contributes to high yield of expected product according to current. Electrolysis of carboxylic acids solutions under controlled potential (2.0 and 2.4 V and chromatographic analysis of the formed products showed that along with the dimeric structures formation for Kolbe reaction, the occurrence of a hydrocarbons mixture takes place, which may be the result of disproportionation of hydrocarbon radicals (alkane and alkene and hydrocarbons of isomeric structure, by further oxidation of the hydrocarbon radical to carbocation and its subsequent transformation into the corresponding saturated and unsaturated isomers. Such statement is not supported by conception of the process of one- and two-electron carboxylic acid oxidation. Discussion: General carboxylic acid oxidation scheme according to one-electron mechanism (dimerization and disproportionation of the radical and two-electron mechanism (formation and carbocation rearrangement is proposed. The formation of hydrocarbons under

  17. Novel Polymers with Carboxylic Acid Loading

    DEFF Research Database (Denmark)

    Thomsen, Anders Daugaard; Malmström, Eva; Hvilsted, Søren

    2006-01-01

    Click chemistry has been used to prepare a range of novel polymers with pendant carboxylic acid side groups. Four azido carboxylic acids, either mono- or difunctional and aliphatic or aromatic, have been prepared and thoroughly characterized. Extensive model reactions with 1-ethyl-4-hydroxybenzene......, the simplest model for poly(4-hydroxystyrene), and the four azido carboxylic acids have been conducted to establish the proper reaction conditions and provide an analytical frame for the corresponding polymers. Poly(4-hydroxystyrene) moieties in three different polymers—poly(4-hydroxystyrene), poly(4...... the polymers in general exhibit [when poly(4-hydroxystyrene) is a substantial part] significant changes in the glass-transition temperature from the polar poly(4-hydroxystyrene) (120–130 °C) to the much less polar alkyne polymers (46–60 °C). A direct correlation between the nature of the pendant groups...

  18. Carboxylic acids in crystallization of macromolecules: learning from successful crystallization experiments.

    Science.gov (United States)

    Offermann, Lesa R; He, John Z; Mank, Nicholas J; Booth, William T; Chruszcz, Maksymilian

    2014-03-01

    The production of macromolecular crystals suitable for structural analysis is one of the most important and limiting steps in the structure determination process. Often, preliminary crystallization trials are performed using hundreds of empirically selected conditions. Carboxylic acids and/or their salts are one of the most popular components of these empirically derived crystallization conditions. Our findings indicate that almost 40 % of entries deposited to the Protein Data Bank (PDB) reporting crystallization conditions contain at least one carboxylic acid. In order to analyze the role of carboxylic acids in macromolecular crystallization, a large-scale analysis of the successful crystallization experiments reported to the PDB was performed. The PDB is currently the largest source of crystallization data, however it is not easily searchable. These complications are due to a combination of a free text format, which is used to capture information on the crystallization experiments, and the inconsistent naming of chemicals used in crystallization experiments. Despite these difficulties, our approach allows for the extraction of over 47,000 crystallization conditions from the PDB. Initially, the selected conditions were investigated to determine which carboxylic acids or their salts are most often present in crystallization solutions. From this group, selected sets of crystallization conditions were analyzed in detail, assessing parameters such as concentration, pH, and precipitant used. Our findings will lead to the design of new crystallization screens focused around carboxylic acids.

  19. Nitric Acid Dehydration Using Perfluoro Carboxylate and Mixed Sulfonate/Carboxylate Membranes

    Energy Technology Data Exchange (ETDEWEB)

    Ames, Richard L. [Colorado School of Mines, Golden, CO (United States)

    2004-09-01

    Perfluoro ionomer membranes are tetrafluoro ethylene-based materials with microheterogeneous structures consisting of a hydrophobic polymer backbone and a hydrophilic side-chain cluster region. Due to the ionomer cluster morphology, these films exhibit unique transport properties. Recent investigations with perfluoro sulfonate and perfluoro sulfonate/carboxylate composite polymers have demonstrated their value in the dehydration of nitric acid and they show potential as an alternative to conventional, energy intensive unit operations in the concentration of acid feeds. As a result, investigations were conducted to determine the feasibility of using pure perfluoro carboxylate and mixed perfluoro sulfonate/carboxylate films for the dehydration of nitric acid because of the speculation of improved water selectivity of the carboxylate pendant chain. During the first phase of these investigations the effort was focused on generating a thin, solution cast perfluoro carboxylate ionomer film, to evaluate the general, chemical and physical characteristics of the polymer, and to assess the material's aqueous transport performance (flux and nitrate separation efficiencies) in pervaporation and high-pressure environments. Results demonstrated that generating robust solution-cast films was difficult yet a number of membranes survived high trans-membrane pressures up to 700 psig. General characterization of the solution cast product showed reduced ion exchange capacities when compared with thicker, ''as received'' perfluoro carboxylate and similar sulfonate films. Small angle x-ray scattering analysis results suggested that the solution cast carboxylate films contained a small fraction of sulfonate terminated side-chains. Aqueous transport experimentation showed that permeate fluxes for both pure water and nitric acid were approximately two orders of magnitude smaller for the carboxylate solution cast membranes when compared to their sulfonate

  20. Cationic mononuclear ruthenium carboxylates as catalyst prototypes for self-induced hydrogenation of carboxylic acids.

    Science.gov (United States)

    Naruto, Masayuki; Saito, Susumu

    2015-08-28

    Carboxylic acids are ubiquitous in bio-renewable and petrochemical sources of carbon. Hydrogenation of carboxylic acids to yield alcohols produces water as the only byproduct, and thus represents a possible next generation, sustainable method for the production of these alternative energy carriers/platform chemicals on a large scale. Reported herein are molecular insights into cationic mononuclear ruthenium carboxylates ([Ru(OCOR)](+)) as prototypical catalysts for the hydrogenation of carboxylic acids. The substrate-derived coordinated carboxylate was found to function initially as a proton acceptor for the heterolytic cleavage of dihydrogen, and subsequently also as an acceptor for the hydride from [Ru-H](+), which was generated in the first step (self-induced catalysis). The hydrogenation proceeded selectively and at high levels of functional group tolerance, a feature that is challenging to achieve with existing heterogeneous/homogeneous catalyst systems. These fundamental insights are expected to significantly benefit the future development of metal carboxylate-catalysed hydrogenation processes of bio-renewable resources.

  1. Correction: Synthesis of pyrrolidine-3-carboxylic acid derivatives via asymmetric Michael addition reactions of carboxylate-substituted enones.

    Science.gov (United States)

    Yin, Feng; Garifullina, Ainash; Tanaka, Fujie

    2018-04-25

    Correction for 'Synthesis of pyrrolidine-3-carboxylic acid derivatives via asymmetric Michael addition reactions of carboxylate-substituted enones' by Feng Yin et al., Org. Biomol. Chem., 2017, 15, 6089-6092.

  2. Modification of polysulfone with pendant carboxylic acid functionality ...

    Indian Academy of Sciences (India)

    polysulfone (PSF) by in situ generated chloromethyl radical in presence of stannic chloride in tetrachloroethane and .... vert the nitrile group to carboxylic acid was reported (Reddy ..... PEG molecular weight vs rejection at 35 psi pressure.

  3. Determination of Carboxylic Acids and Water-soluble Inorganic Ions ...

    African Journals Online (AJOL)

    NICO

    radiation balance.4,5 Major water-soluble inorganic ions are associated with atmospheric ... molecular weight carboxylic acids in aerosol samples collected from a rural ... include biomass burning, agriculture, livestock and soil dust. Tropical ...

  4. Salt and cocrystals of sildenafil with dicarboxylic acids: solubility and pharmacokinetic advantage of the glutarate salt.

    Science.gov (United States)

    Sanphui, Palash; Tothadi, Srinu; Ganguly, Somnath; Desiraju, Gautam R

    2013-12-02

    Sildenafil is a drug used to treat erectile dysfunction and pulmonary arterial hypertension. Because of poor aqueous solubility of the drug, the citrate salt, with improved solubility and pharmacokinetics, has been marketed. However, the citrate salt requires an hour to reach its peak plasma concentration. Thus, to improve solubility and bioavailability characteristics, cocrystals and salts of the drug have been prepared by treating aliphatic dicarboxylic acids with sildenafil; the N-methylated piperazine of the drug molecule interacts with the carboxyl group of the acid to form a heterosynthon. Salts are formed with oxalic and fumaric acid; salt monoanions are formed with succinic and glutaric acid. Sildenafil forms cocrystals with longer chain dicarboxylic acids such as adipic, pimelic, suberic, and sebacic acids. Auxiliary stabilization via C-H···O interactions is also present in these cocrystals and salts. Solubility experiments of sildenafil cocrystal/salts were carried out in 0.1N HCl aqueous medium and compared with the solubility of the citrate salt. The glutarate salt and pimelic acid cocrystal dissolve faster than the citrate salt in a two hour dissolution experiment. The glutarate salt exhibits improved solubility (3.2-fold) compared to the citrate salt in water. Solubilities of the binary salts follow an inverse correlation with their melting points, while the solubilities of the cocrystals follow solubilities of the coformer. Pharmacokinetic studies on rats showed that the glutarate salt exhibits doubled plasma AUC values in a single dose within an hour compared to the citrate salt. The high solubility of glutaric acid, in part originating from the strained conformation of the molecule and its high permeability, may be the reason for higher plasma levels of the drug.

  5. Pd(II)/Bipyridine-Catalyzed Conjugate Addition of Arylboronic Acids to α,β-Unsaturated Carboxylic Acids. Synthesis of β-Quaternary Carbons Substituted Carboxylic Acids.

    Science.gov (United States)

    Liu, Rui; Yang, Zhenyu; Ni, Yuxin; Song, Kaixuan; Shen, Kai; Lin, Shaohui; Pan, Qinmin

    2017-08-04

    Pd(II)/bipyridine-catalyzed conjugate addition of arylboronic acids to α,β-unsaturated carboxylic acids (including β,β-disubstituted acrylic acids) was developed and optimized, which provided a mild and convenient method for the highly challenging synthesis of β-quaternary carbons substituted carboxylic acids.

  6. CARBOXYLIC ACIDS OF HERB OF THYMUS CRETACEUS KLOK. ET SCHOST

    Directory of Open Access Journals (Sweden)

    V. N. Bubenchikova

    2014-01-01

    Full Text Available We have studied carboxylic acids of the herb of Thymus cretaceus Klok. et Schost which is widespread on a territory of some regions (Belgorod, Voronezh. The study was carried out using gas-liquid chromatography at Agilent Technologies 6890 chromatographer with massspectrometric detector 5973 N. Acids concentration was calculated by means of inner standard.We have established that carboxylic acids of Thymus cretaceus are represented by 34 compounds. Palmitic (1779.02 mg/kg, behenic (1084.15 mg/kg, levulinic (986.24 mg/kg and linoleic acids (678.82 mg/kg predominate among fatty acids; citric (9835.14 mg/kg, malonic (447.91 mg/kg and oxalic acids (388.32 mg/kg predominate among organic acids; andferulic acid predominate amongphenolcarbonic acids.

  7. Dimerization of Carboxylic Acids: An Equation of State Approach

    DEFF Research Database (Denmark)

    Tsivintzelis, Ioannis; Kontogeorgis, Georgios; Panayiotou, Costas

    2017-01-01

    The association term of the nonrandom hydrogen bonding theory, which is an equation of state model, is extended to describe the dimerization of carboxylic acids in binary mixtures with inert solvents and in systems of two different acids. Subsequently, the model is applied to describe the excess...

  8. Synthesis and characterization of carboxylic acid functionalized silicon nanoparticles

    Science.gov (United States)

    Shaner, Ted V.

    Silicon nanoparticles are of great interest in a great number of fields. Silicon nanoparticles show great promise particularly in the field of bioimaging. Carboxylic acid functionalized silicon nanoparticles have the ability to covalently bond to biomolecules through the conjugation of the carboxylic acid to an amine functionalized biomolecule. This thesis explores the synthesis of silicon nanoparticles functionalized by both carboxylic acids and alkenes and their carboxylic acid functionality. Also discussed is the characterization of the silicon nanoparticles by the use of x-ray spectroscopy. Finally, the nature of the Si-H bond that is observed on the surface of the silicon nanoparticles will be investigated using photoassisted exciton mediated hydrosilation reactions. The silicon nanoparticles are synthesized from both carboxylic acids and alkenes. However, the lack of solubility of diacids is a significant barrier to carboxylic acid functionalization by a mixture of monoacids and diacids. A synthesis route to overcome this obstacle is to synthesize silicon nanoparticles with terminal vinyl group. This terminal vinyl group is distal to the surface of the silicon nanoparticle. The conversion of the vinyl group to a carboxylic acid is accomplished by oxidative cleavage using ozonolysis. The carboxylic acid functionalized silicon nanoparticles were then successfully conjugated to amine functionalized DNA strand through an n-hydroxy succinimide ester activation step, which promotes the formation of the amide bond. Conjugation was characterized by TEM and polyacrylamide gel electrophoresis (PAGE). The PAGE results show that the silicon nanoparticle conjugates move slower through the polyacrylamide gel, resulting in a significant separation from the nonconjugated DNA. The silicon nanoparticles were then characterized by the use of x-ray absorption near edge spectroscopy (Xanes) and x-ray photoelectron spectroscopy (XPS) to investigate the bonding and chemical

  9. Facile synthesis of α-hydroxy carboxylic acids from the corresponding α-amino acids

    DEFF Research Database (Denmark)

    Stuhr-Hansen, Nicolai; Padrah, Shahrokh; Strømgaard, Kristian

    2014-01-01

    An effective and improved procedure is developed for the synthesis of α-hydroxy carboxylic acids by treatment of the corresponding protonated α-amino acid with tert-butyl nitrite in 1,4-dioxane-water. The amino moiety must be protonated and located α to a carboxylic acid function in order...

  10. The Conversion of Carboxylic Acids to Ketones: A Repeated Discovery

    Science.gov (United States)

    Nicholson, John W.; Wilson, Alan

    2004-09-01

    This article describes the history of the reaction converting carboxylic acids to ketones. The reaction has been rediscovered several times, yet has actually been known for centuries. The best known version of the process is the Dakin West reaction (1928), which applies to α-amino acids and also involves the simultaneous conversion of the amine group to amido functionality. Unlike other examples, this particular reaction has attracted a reasonable amount of attention and it appears to be better known than the conversion of simple carboxylic acids to ketones. However, this reaction was described as long ago as 1612, when Beguin published an account of it in his book, Tyrocinium Chymicum . Since then, many chemists have rediscovered the reaction, apparently independently. One of the earliest modern accounts was by W. H. Perkin, Sr., in 1886, who made various simple ketones by refluxing the appropriate carboxylic acids with base. However, this work has been largely ignored, including by his son, W. H. Perkin, Jr., who used a more complicated base-catalyzed ketonization to prepare small ring compounds in the early years of the 20th century. Other articles detailing the application of ketonization to organic acids are discussed, including our own work, which employed the process to crosslink carboxylated polymers for possible technical application in coatings. Despite its relative obscurity, the reaction was used by Woodward et al. in the total synthesis of strychnine, reported in 1963, and this is discussed in detail at the end of the article. See Featured Molecules .

  11. Determination of Carboxylic Acids and Water-soluble Inorganic Ions ...

    African Journals Online (AJOL)

    Atmospheric aerosol samples of PM2.5 and PM10 were collected in April–May 2011 from a rural site in Tanzania and analyzed for water-soluble inorganic ions and low molecular weight carboxylic acids using ion chromatography. PM2.5 and PM10 low-volume samplers with quartz fibre filters were deployed and aerosol ...

  12. Cloning of phenazine carboxylic acid genes of Fusarium fujikuroi ...

    African Journals Online (AJOL)

    STORAGESEVER

    2010-03-08

    Mar 8, 2010 ... genetic modification can improve the efficacy of biological control agents (Van Loon, 1998). Bacterial secondary ... WCS358r was modified to produce the antifungal com- pound phenazine-1-carboxylic acid (PCA) ( ..... control of Rhizoctonia solani in tomato. J. Biotechnol. 6: 115-127. Raaijmakers JM ...

  13. Separation and determination of some carboxylic acids by capillary electrophoresis

    Energy Technology Data Exchange (ETDEWEB)

    Sladkov, V.; Fourest, B

    2006-07-01

    Separation and determination of some organic acids, mono-carboxylic (formic and acetic), dicarboxylic (oxalic and tartaric), tricarboxylic (citric) acids and aromatic acids (phtalic, benzoic, mellitic and trimellitic), by capillary electrophoresis are reviewed. The method development parameters, such as separation and injection mode, are discussed. Special attention is paid to the comparison of different detection types (spectroscopic and electrochemical). The optimisation of the carrier electrolyte composition (choice of carrier electrolyte, effect of pH, ionic strength, electro-osmotic flow modifier) is treated. Different additives (alkali-earth and transition metal ions, cyclodextrins and alcohol), which are often used for improving organic acid separation, are also considered. (authors)

  14. Separation and determination of some carboxylic acids by capillary electrophoresis

    International Nuclear Information System (INIS)

    Sladkov, V.; Fourest, B.

    2006-01-01

    Separation and determination of some organic acids, mono-carboxylic (formic and acetic), dicarboxylic (oxalic and tartaric), tricarboxylic (citric) acids and aromatic acids (phtalic, benzoic, mellitic and trimellitic), by capillary electrophoresis are reviewed. The method development parameters, such as separation and injection mode, are discussed. Special attention is paid to the comparison of different detection types (spectroscopic and electrochemical). The optimisation of the carrier electrolyte composition (choice of carrier electrolyte, effect of pH, ionic strength, electro-osmotic flow modifier) is treated. Different additives (alkali-earth and transition metal ions, cyclodextrins and alcohol), which are often used for improving organic acid separation, are also considered. (authors)

  15. Extraction of scandium by aromatic carboxylic acids

    International Nuclear Information System (INIS)

    Kamenev, V.F.; Fadeeva, V.I.

    1977-01-01

    Extraction of complex compounds af scandium with salicylic, phenyl- and diphenylacetic acids with chloroform solutions of tetraethyldiamideheptylphosphate as a donor-active additive in relation to the pH and reagent concentration has been studied. Extraction of salicylates of some elements (Ta, Nb, Zr, Hf, Mo) by solutions of tetraethyldiamideheptylphosphate in chloroform has been investigated, and the possibility of their extraction separation from scandium is shown

  16. Reaction between molybdenum hexafluoride and carboxylic acids

    International Nuclear Information System (INIS)

    Shustov, L.D.; Nikolenko, L.N.; Senchenkova, T.M.

    1983-01-01

    Trifluoromethyl derivatives of pyridine, imidazole and difluoromethane are synthesized during interaction of MoF 6 surplUs (190-210 deg) with nicotine-isomicotine-, 2,6-pyridinedicarboxylic-, 4,5-imidazoledicarboxyclic- and diffluoroacetic acids. The yield of trifluoromethyl derivatives attains 84%. Molybdenum hexafluoride offers some advantages in comparisoo with toxic SF 4 . MoF 6 toxicity is low; leakage of MoF 6 vapors is easily detected

  17. Extraction of scandium by aromatic carboxylic acids

    Energy Technology Data Exchange (ETDEWEB)

    Kamenev, V F; Fadeeva, V I [Moskovskij Gosudarstvennyj Univ. (USSR)

    1977-04-01

    Extraction of complex compounds af scandium with salicylic, phenyl- and diphenylacetic acids with chloroform solutions of tetraethyldiamideheptylphosphate as a donor-active additive in relation to the pH and reagent concentration has been studied. Extraction of salicylates of some elements (Ta, Nb, Zr, Hf, Mo) by solutions of tetraethyldiamideheptylphosphate in chloroform has been investigated, and the possibility of their extraction separation from scandium is shown.

  18. Carboxylic acid-functionalized SBA-15 nanorods for gemcitabine delivery

    International Nuclear Information System (INIS)

    Bahrami, Zohreh; Badiei, Alireza; Ziarani, Ghodsi Mohammadi

    2015-01-01

    The present study deals with the functionalization of mesoporous silica nanoparticles as drug delivery systems. Mono, di, and tri amino-functionalized SBA-15 nanorods were synthesized by post-grafting method using (3-aminopropyl) triethoxysilane, N-(2-aminoethyl-)3- aminopropyltrimethoxysilane, and 3-[2-(2-aminoethylamino) ethylamino] propyl trimethoxysilane, respectively. The carboxylic acid derivatives of the amino-functionalized samples were obtained using succinic anhydride. Tminopropyltrimethoxysilanehe obtained modified materials were investigated as matrixes for the anticancer drug (gemcitabine) delivery. The prepared samples were characterized by SAXS, N 2 adsorption/desorption, SEM, transmission electron microscopy, thermogravimetric analysis, and FTIR and UV spectroscopies. The adsorption and release properties of all samples were studied. It was revealed that the adsorption capacity and release behavior of gemcitabine were highly dependent on the type of the introduced functional groups. The carboxylic acid-modified samples have higher loading content, due to the strong interaction with gemcitabine. The maximum content of deposited drug in the modified SBA-15 nanorods is close to 40 wt%. It was found that the surface functionalization leads toward significant decrease of the drug release rate. The carboxylic acid-functionalized samples have slower release rate in contrast with the amino-functionalized samples

  19. Extraction characteristics of trivalent lanthanides and actinides in mixtures of dinonylnaphthalenesulfonic acid and carboxylic acids

    International Nuclear Information System (INIS)

    West, M.H.

    1983-03-01

    Dinonylnaphthalenesulfonic acid (HDNNS) has been shown to be an effective liquid cation exchanger for the extraction of metal ions. This extractant has proven to be successful in the extraction of trivalent lanthanides and actinides in the pH range of 2.0 to 3.0, although it shows little selectivity for individual ions because of its strong acid character. In an effort to improve the selectivity of HDNNS between trivalent lanthanides and actinides, carboxylic acids were added to the organic phase and the effects on the extraction characteristics of HDNNS were investigated. Three carboxylic acids - nonanoic, cyclohexanecarboxylic, and cyclohexanebutyric - were studied with the following metals: Am(III), Cm(III), Ce(III), Eu(III), and Tm(III). The distributions of the metal ions were studied holding the HDNNS concentration constant while varying the carboxylic acid concentrations over a range of 1.0 x 10 -5 M to 1.0 M. Results indicated that the greatest enhancement of the extraction occurred at a carboxylic acid concentration of 1.0 x 10 -2 M with negative effects occurring at 0.5 M and 1.0 M. The effects on the extraction of the trivalent lanthanides and actinides were interpreted in terms of the structural differences of the carboxylic acids, the effect of the carboxylic acids on the HDNNS extraction mechanism, and the ionic properties of the metals studied

  20. Development of starch biofilms using different carboxylic acids as plasticizers

    International Nuclear Information System (INIS)

    Cruz, L.C.; Miranda, C.S.; Santos, W.J. dos; Goncalves, A.P.B.; Oliveira, J.C.; Jose, N.M.

    2014-01-01

    Biodegradable films have become a widely exploited issue among scientists because of their positive environmental impact, besides their potential to promote better food conservation and an increase in shelf life. Starch has been studied in this field due to its availability, low cost and biodegradability. However, starch films tend to be brittle and they need addition of a plasticizer to enable their usage. In this work, starch films were synthesized with different carboxylic acids as plasticizers, aiming to observe the effect of the acids chain size in the final films properties. The acids used were: oxalic, succinic and adipic. The materials were produced by casting and characterized by DSC, TG, DRX e FTIR. It was observed that the acids chain size influenced on the thermal and structural properties of the films. (author)

  1. A comprehensive evaluation of the toxicology of cigarette ingredients: aliphatic and aromatic carboxylic acids.

    Science.gov (United States)

    Coggins, Christopher R E; Liu, Jianmin; Merski, Jerome A; Werley, Michael S; Oldham, Michael J

    2011-06-01

    Aromatic and aliphatic carboxylic acids are present in tobacco and tobacco smoke. A battery of tests was used to compare the toxicity of mainstream smoke from experimental cigarettes containing eight aromatic and aliphatic carboxylic acids and the salt of one acid that were added individually at three different levels (lowest and highest target inclusions were 100 and 90,000 ppm, respectively). Mainstream smoke from cigarettes containing each of the test ingredients was evaluated using analytical chemistry and assays to measure in vitro cytotoxicity (neutral red uptake) and Salmonella (five strains) mutagenicity. For four of the compounds (citric, lactic, benzoic acids, and sodium benzoate), 90-day rodent inhalation studies were also performed. Although sporadic statistically significant differences in some experimental cigarette smoke constituents occurred, none resulted in significant changes in mutagenicity or cytotoxicity responses, nor in responses measured in the inhalation studies, except for lactic acid (LA). Inclusion of LA resulted in dose-dependent increase in water and caused a dose-dependent decrease in cytotoxicity. Incorporation of LA into cigarettes resulted in several dose-related reductions in histopathology, which were largely restricted to the nasal passages. Incorporation of LA also ameliorated some of the typical decrease in body weight gain seen in cigarette smoke-exposed rats. Inclusion of these ingredients at exaggerated use levels resulted in sporadic dose-related and treatment effects for some smoke constituents, but no toxicological response was noted in the in vitro and in vivo tests performed.

  2. l-2-Nitrimino-1,3-diazepane-4-carboxylic acid

    Directory of Open Access Journals (Sweden)

    Harutyun A. Karapetyan

    2008-05-01

    Full Text Available The cyclic form of l-nitroarginine, C6H10N4O4, crystallizes with two independent molecules in the asymmetric unit. According to the geometrical parameters, similar in both molecules, the structure corresponds to that of l-2-nitrimino-1,3-diazepane-4-carboxylic acid; there are, however, conformational differences between the independent molecules, one of them being close to a twisted chair while the other might be described as a rather flattened boat. All six active H atoms in the two molecules are involved in hydrogen bonds, two of which are intramolecular and four intermolecular, forming an infinite chain of molecules along the b axis.

  3. Formation of biologically relevant carboxylic acids during the gamma irradiation of acetic acid

    Science.gov (United States)

    Negron-Mendoza, A.; Ponnamperuma, C.

    1976-01-01

    Irradiation of aqueous solutions of acetic acid with gamma rays produced several carboxylic acids in small yield. Their identification was based on the technique of gas chromatography combined with mass spectrometry. Some of these acids are Krebs Cycle intermediates. Their simultaneous formation in experiments simulating the primitive conditions on the earth suggests that metabolic pathways may have had their origin in prebiotic chemical processes.

  4. Atmospheric chemistry of carboxylic acids: microbial implication versus photochemistry

    Science.gov (United States)

    Vaïtilingom, M.; Charbouillot, T.; Deguillaume, L.; Maisonobe, R.; Parazols, M.; Amato, P.; Sancelme, M.; Delort, A.-M.

    2011-08-01

    The objective of this work was to compare experimentally the contribution of photochemistry vs. microbial activity to the degradation of carboxylic acids present in cloud water. For this, we selected 17 strains representative of the microflora existing in real clouds and worked on two distinct artificial cloud media that reproduce marine and continental cloud chemical composition. Photodegradation experiments with hydrogen peroxide (H2O2) as a source of hydroxyl radicals were performed under the same microcosm conditions using two irradiation systems. Biodegradation and photodegradation rates of acetate, formate, oxalate and succinate were measured on both media at 5 °C and 17 °C and were shown to be on the same order of magnitude (around 10-10-10-11 M s-1). The chemical composition (marine or continental origin) had little influence on photodegradation and biodegradation rates while the temperature shift from 17 °C to 5 °C decreased biodegradation rates of a factor 2 to 5. In order to test other photochemical scenarios, theoretical photodegradation rates were calculated considering hydroxyl (OH) radical concentration values in cloud water estimated by cloud chemistry modelling studies and available reaction rate constants of carboxylic compounds with both hydroxyl and nitrate radicals. Considering high OH concentration ([OH] = 1 × 10-12 M) led to no significant contribution of microbial activity in the destruction of carboxylic acids. On the contrary, for lower OH concentration (at noon, [OH] = 1 × 10-14 M), microorganisms could efficiently compete with photochemistry and in similar contributions than the ones estimated by our experimental approach. Combining these two approaches (experimental and theoretical), our results led to the following conclusions: oxalate was only photodegraded; the photodegradation of formate was usually more efficient than its biodegradation; the biodegradation of acetate and succinate seemed to exceed their photodegradation.

  5. In situ Recovery of Bio-Based Carboxylic Acids

    Energy Technology Data Exchange (ETDEWEB)

    Karp, Eric M [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Saboe, Patrick [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Manker, Lorenz [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Michener, William E [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Peterson, Darren J [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Brandner, David [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Deutch, Stephen P [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Cywar, Robin [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Beckham, Gregg T [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Kumar, Manish [Pennsylvania State University

    2018-03-16

    The economics of chemical and biological processes is often dominated by the expense of downstream product separations from dilute product streams. Continuous separation techniques, such as in situ product recovery (ISPR), are attractive in that they can concentrate products from a reactor and minimize solvent loss, thereby increasing purity and sustainability of the process. In bioprocesses, ISPR can have an additional advantage of increasing productivity by alleviating product inhibition on the microorganism. In this work, we developed a liquid-liquid extraction (LLE)-based ISPR system integrated with downstream distillation to selectively purify free carboxylic acids, which were selected as exemplary bioproducts due to their ability to be produced at industrially relevant titers and productivities. Equilibrium constants for the extraction of carboxylic acids into a phosphine-oxide based organic phase were experimentally determined. Complete recovery of acids from the extractant and recyclability of the organic phase were demonstrated through multiple extraction-distillation cycles. Using these data, an equilibrium model was developed to predict the acid loading in the organic phase as a function of the extraction equilibrium constant, initial aqueous acid concentration, pH, organic to aqueous volume ratio, and temperature. A distillation process model was then used to predict the energy input required to distill neat acid from an organic phase as a function of the acid loading in the organic phase feed. The heat integrated distillation train can achieve neat recovery of acetic acid with an energy input of 2.6 MJ kg-1 of acetic acid. This LLE-based ISPR system integrated with downstream distillation has an estimated carbon footprint of less than 0.36 kg CO2 per kg of acetic acid, and provides a green approach to enable both new industrial bioprocesses, and process intensification of existing industrial operations by (1) increasing the productivity and titer of

  6. Catalytic transformation of functionalized carboxylic acids using multifunctional rhenium complexes.

    Science.gov (United States)

    Naruto, Masayuki; Agrawal, Santosh; Toda, Katsuaki; Saito, Susumu

    2017-06-13

    Carboxylic acids (CAs) are one of the most ubiquitous and important chemical feedstocks available from biorenewable resources, CO 2 , and the petrochemical industry. Unfortunately, chemoselective catalytic transformations of CH n CO 2 H (n = 1-3) groups into other functionalities remain a significant challenge. Herein, we report rhenium V complexes as extremely effective precatalysts for this purpose. Compared to previously reported heterogeneous and homogeneous catalysts derived from high- or low-valent metals, the present method involves a α-C-H bond functionalization, a hydrogenation, and a hydrogenolysis, which affords functionalized alcohols with a wide substrate scope and high chemoselectivity under relatively mild reaction conditions. The results represent an important step toward a paradigm shift from 'low-valent' to 'high-valent' metal complexes by exploring a new portfolio of selective functional group transformations of highly oxygenated organic substrates, as well as toward the exploitation of CAs as a valuable biorenewable feedstock.

  7. Aerosol volatility and enthalpy of sublimation of carboxylic acids.

    Science.gov (United States)

    Salo, Kent; Jonsson, Asa M; Andersson, Patrik U; Hallquist, Mattias

    2010-04-08

    The enthalpy of sublimation has been determined for nine carboxylic acids, two cyclic (pinonic and pinic acid) and seven straight-chain dicarboxylic acids (C(4) to C(10)). The enthalpy of sublimation was determined from volatility measurements of nano aerosol particles using a volatility tandem differential mobility analyzer (VTDMA) set-up. Compared to the previous use of a VTDMA, this novel method gives enthalpy of sublimation determined over an extended temperature range (DeltaT approximately 40 K). The determined enthalpy of sublimation for the straight-chain dicarboxylic acids ranged from 96 to 161 kJ mol(-1), and the calculated vapor pressures at 298 K are in the range of 10(-6)-10(-3) Pa. These values indicate that dicarboxylic acids can take part in gas-to-particle partitioning at ambient conditions and may contribute to atmospheric nucleation, even though homogeneous nucleation is unlikely. To obtain consistent results, some experimental complications in producing nanosized crystalline aerosol particles were addressed. It was demonstrated that pinonic acid "used as received" needed a further purification step before being suspended as a nanoparticle aerosol. Furthermore, it was noted from distinct differences in thermal properties that aerosols generated from pimelic acid solutions gave two types of particles. These two types were attributed to crystalline and amorphous configurations, and based on measured thermal properties, the enthalpy of vaporization was 127 kJ mol(-1) and that of sublimation was 161 kJ mol(-1). This paper describes a new method that is complementary to other similar methods and provides an extension of existing experimental data on physical properties of atmospherically relevant compounds.

  8. Atmospheric chemistry of carboxylic acids: microbial implication versus photochemistry

    Directory of Open Access Journals (Sweden)

    M. Vaïtilingom

    2011-08-01

    Full Text Available The objective of this work was to compare experimentally the contribution of photochemistry vs. microbial activity to the degradation of carboxylic acids present in cloud water. For this, we selected 17 strains representative of the microflora existing in real clouds and worked on two distinct artificial cloud media that reproduce marine and continental cloud chemical composition. Photodegradation experiments with hydrogen peroxide (H2O2 as a source of hydroxyl radicals were performed under the same microcosm conditions using two irradiation systems. Biodegradation and photodegradation rates of acetate, formate, oxalate and succinate were measured on both media at 5 °C and 17 °C and were shown to be on the same order of magnitude (around 10−10–10−11 M s−1. The chemical composition (marine or continental origin had little influence on photodegradation and biodegradation rates while the temperature shift from 17 °C to 5 °C decreased biodegradation rates of a factor 2 to 5.

    In order to test other photochemical scenarios, theoretical photodegradation rates were calculated considering hydroxyl (OH radical concentration values in cloud water estimated by cloud chemistry modelling studies and available reaction rate constants of carboxylic compounds with both hydroxyl and nitrate radicals. Considering high OH concentration ([OH] = 1 × 10−12 M led to no significant contribution of microbial activity in the destruction of carboxylic acids. On the contrary, for lower OH concentration (at noon, [OH] = 1 × 10−14 M, microorganisms could efficiently compete with photochemistry and in similar contributions than the ones estimated by our experimental approach.

    Combining these two approaches (experimental and theoretical, our results led to the following conclusions: oxalate was only photodegraded; the photodegradation of formate was usually more

  9. Performances of carbon-based screen-printed electrodes modified by diazonium salts with various carboxylic functions for trace metal sensors

    International Nuclear Information System (INIS)

    Bouden, Sarra; Bellakhal, Nizar; Chausse, Annie; Vautrin-Ul, Christine

    2014-01-01

    The electrochemically induced functionalization of carbon-based screen-printed-electrodes (SPEs) by phenyl groups, having one or two carboxylic functions, was achieved by reduction of in situ generated diazonium salts in aqueous media. The corresponding diazonium cations of 4-aminobenzoic acid, 4-aminophthalic acid, 3-(4-aminophenyl) propionic acid, 3-(4-aminophenyl)-2-propenoic acid and 5-aminoisophthalic acid were generated in situ with sodium nitrite in aqueous H_2SO_4. The electrochemical detection of Pb(II) with the grafted SPEs was investigated using Pb(II) 5 * 10"-"8 M solutions. The performances of the grafted SPEs were found to be dependent on the number of carboxylic groups, on their position on the phenyl ring, on the olefinic or the aliphatic character of the chain bearing the carboxylic group. The performances of mono-4-carboxyphenyl and 3,5-dicarboxyphenyl grafted SPEs for Cd(II) and Cu(II) trace detection were tested and compared. (authors)

  10. Determination of perfluoroalkyl carboxylic, sulfonic, and phosphonic acids in food.

    Science.gov (United States)

    Ullah, Shahid; Alsberg, Tomas; Vestergren, Robin; Berger, Urs

    2012-11-01

    A sensitive and accurate method was developed and validated for simultaneous analysis of perfluoroalkyl carboxylic acids, sulfonic acids, and phosphonic acids (PFPAs) at low picograms per gram concentrations in a variety of food matrices. The method employed extraction with acetonitrile/water and cleanup on a mixed-mode co-polymeric sorbent (C8 + quaternary amine) using solid-phase extraction. High-performance liquid chromatographic separation was achieved on a C18 column using a mobile phase gradient containing 5 mM 1-methyl piperidine for optimal chromatographic resolution of PFPAs. A quadrupole time-of-flight high-resolution mass spectrometer operating in negative ion mode was used as detector. Method detection limits were in the range of 0.002 to 0.02 ng g(-1) for all analytes. Sample preparation (extraction and cleanup) recoveries at a spiking level of 0.1 ng g(-1) to a baby food composite were in the range of 59 to 98 %. A strong matrix effect was observed in the analysis of PFPAs in food extracts, which was tentatively assigned to sorption of PFPAs to the injection vial in the solvent-based calibration standard. The method was successfully applied to a range of different food matrices including duplicate diet samples, vegetables, meat, and fish samples.

  11. An improved synthesis of carbon-14 labelled carboxylic acids from carbon-14 labelled amino acids

    International Nuclear Information System (INIS)

    Ramamurthy, T.V.; Ravi, S.; Viswanathan, K.V.

    1988-01-01

    Various carbon-14 labelled amino acids including the aromatic ones viz., tyrosine, phenylalanine and tryptophan are converted to the corresponding carboxylic acids in high yield (70-90%) on a micromolar scale synthesis by reaction with hydroxyl-amine-O-sulphonic acid and in a short reaction time. The improvement in yield has been achieved by using aqeuous alcohol as solvent in lieu of water alone as the medium of reaction. (author)

  12. 40 CFR 721.2088 - Carboxylic acids, (C6-C9) branched and linear.

    Science.gov (United States)

    2010-07-01

    ... linear. 721.2088 Section 721.2088 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... Specific Chemical Substances § 721.2088 Carboxylic acids, (C6-C9) branched and linear. (a) Chemical... as carboxylic acids, (C6-C9) branched and linear (PMNs P-93-313, 314, 315, and 316) are subject to...

  13. Synthesis and bioactivities of Phenazine-1-carboxylic acid derivatives based on the modification of PCA carboxyl group.

    Science.gov (United States)

    Xiong, Zhipeng; Niu, Junfan; Liu, Hao; Xu, Zhihong; Li, Junkai; Wu, Qinglai

    2017-05-01

    Phenazine-1-carboxylic acid (PCA) as a natural product widely exists in microbial metabolites of Pseudomonads and Streptomycetes and has been registered for the fungicide against rice sheath blight in China. To find higher fungicidal activities compounds and study the effects on fungicidal activities after changing the carboxyl group of PCA, we synthesized a series of PCA derivatives by modifying the carboxyl group of PCA and their structures were confirmed by 1 H NMR and HRMS. Most compounds exhibited significant fungicidal activities in vitro. In particular, compound 6 exhibited inhibition effect against Rhizoctonia solani with EC 50 values of 4.35mg/L and compound 3b exhibited effect against Fusarium graminearum with EC 50 values of 8.30mg/L, compared to the positive control PCA with its EC 50 values of 7.88mg/L (Rhizoctonia solani) and 127.28mg/L (Fusarium graminearum), respectively. The results indicated that the carboxyl group of PCA could be modified to be amide group, acylhydrazine group, ester group, methyl, hydroxymethyl, chloromethyl and ether group etc. And appropriate modifications on carboxyl group of PCA were useful to extend the fungicidal scope. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. SYNTHESIS OF FLAVANONE-6-CARBOXYLIC ACID DERIVATIVES FROM SALICYLIC ACID DERIVATIVE

    Directory of Open Access Journals (Sweden)

    Muhammad Idham Darussalam Mardjan

    2012-02-01

    Full Text Available Synthesis of flavanone-6-carboxylic acid derivatives had been conducted via the route of chalcone. The synthesis was carried out from salicylic acid derivative, i.e. 4-hydroxybenzoic acid, via esterification, Fries rearrangement, Claisen-Schmidt condensation and 1,4-nucleophilic addition reactions. Structure elucidation of products was performed using FT-IR, 1H-NMR, GC-MS and UV-Vis spectrometers. Reaction of 4-hydroxybenzoic acid with methanol catalyzed with sulfuric acid produced methyl 4-hydroxybenzoate in 87% yield. The acid-catalyzed-acetylation of the product using acetic anhydride gave methyl 4-acetoxybenzoate in 75% yield. Furthermore, solvent-free Fries rearrangement of methyl 4-acetoxybenzoate in the presence of AlCl3 produced 3-acetyl-4-hydroxybenzoic acid as the acetophenone derivatives in 67% yield. Then, Claisen-Schmidt condensation of the acetophenone and benzaldehyde derivatives of p-anisaldehyde and veratraldehyde in basic condition gave 2'-hydroxychalcone-5'-carboxylic acid derivatives  in 81 and 71 % yield, respectively. Finally, the ring closure reaction of the chalcone yielded the corresponding flavanone-6-carboxylic acids in 67 and 59% yield, respectively.

  15. Dielectric properties of supramolecular ionic structures obtained from multifunctional carboxylic acids and amines

    DEFF Research Database (Denmark)

    Gonzalez, Lidia; Yu, Liyun; Hvilsted, Søren

    2014-01-01

    The dielectric properties of several supramolecular ionic polymers and networks, linked by the ammonium salts of hexamethylene diamine (HMDA), tris(2-aminoethyl)amine (TAEA), poly(propylene imine) (PPI) dendrimers and two short bis carboxymethyl ether-terminated poly(ethylene glycol)s (Di......COOH-PEG), are reported in this paper. All supramolecular ionic polymers and networks exhibit very high relative dielectric permittivities ( 3 0 )( 10 2 – 10 6 ) at low frequencies, and signi fi cantly lower values (from 1 up to 26) at high frequencies. Additionally, the dielectric properties of supramolecular ionic......), are investigated. Here the relative dielectric permittivities of the supramolecular ionic structures formed with the multifunctional carboxylic acids were lower than those from the supramolecular ionic structures formed with the two carboxymethyl ether-terminated poly(ethylene glycol)s....

  16. Thermochemistry of aqueous pyridine-3-carboxylic acid (nicotinic acid)

    Energy Technology Data Exchange (ETDEWEB)

    Goncalves, Elsa M. [Departamento de Quimica e Bioquimica, Faculdade de Ciencias, Universidade de Lisboa, 1749-016 Lisboa (Portugal); Instituto Politecnico de Setubal, ESTBarreiro, Rua Americo da Silva Marinho, 2839-001 Lavradio (Portugal); Rego, Talita S. [Departamento de Quimica e Bioquimica, Faculdade de Ciencias, Universidade de Lisboa, 1749-016 Lisboa (Portugal); Minas da Piedade, Manuel E., E-mail: memp@fc.ul.p [Departamento de Quimica e Bioquimica, Faculdade de Ciencias, Universidade de Lisboa, 1749-016 Lisboa (Portugal)

    2011-06-15

    Research highlights: {yields} We determined the {Delta}{sub sol}H{sub m} of solid nicotinic acid (NA) in water by solution calorimetry. {yields} We determined {Delta}{sub dil}H{sub m} of an aqueous nicotinic acid solution by flow calorimetry. {yields} We determined (aq, {infinity}) for the 3 NA species involved in acid/base equilibria. {yields} We determined the enthalpy of formation of NA(aq) under saturation conditions.. - Abstract: The molar enthalpy of solution of solid nicotinic acid (NA) at T = 298.15 K, to give an aqueous solution of molality m = 3.748 . 10{sup -3} mol {center_dot} kg{sup -1}, was determined as {Delta}{sub sol}H{sub m} = (19,927 {+-} 48) J {center_dot} mol{sup -1}, by solution calorimetry. Enthalpies of dilution, {Delta}{sub dil}H{sub m}, of 0.1005 mol {center_dot} kg{sup -1} aqueous nicotinic acid to yield final solutions with molality in the approximate range (0.03 to 0.09) mol {center_dot} kg{sup -1} were also measured by flow calorimetry. Combining the two sets of data and the results of pH measurements, with values of proton dissociation enthalpies and {Delta}{sub f}H{sub m}{sup 0}(NA, cr) selected from the literature, it was possible to derive the standard molar enthalpies of formation of the three nicotinic acid species involved in protonation/deprotonation equilibria, at infinite dilution: {Delta}{sub f}H{sub m}{sup 0}(HN{sup +}C{sub 5}H{sub 4}COOH.{infinity}H{sub 2}O,aq) = (328.2 {+-} 1.2) kJ {center_dot} mol{sup -1}, {Delta}{sub f}H{sub m}{sup 0}(HN{sup +}C{sub 5}H{sub 4}COO{sup -}.{infinity}H{sub 2}O,aq) = (325.0 {+-} 1.2) kJ {center_dot} mol{sup -1}, and {Delta}{sub f}H{sub m}{sup 0}(NC{sub 5}H{sub 4}COO{sup -}.{infinity}H{sub 2}O,aq) = (313.7 {+-} 1.2) kJ {center_dot} mol{sup -1}. Finally, the enthalpy of solution of nicotinic acid at T = 298.15 K, under saturation conditions (m = 0.138 mol {center_dot} kg{sup -1}), and the standard molar enthalpy of formation of the corresponding solution could also be obtained as {Delta

  17. Comparative in vitro toxicity assessment of perfluorinated carboxylic acids.

    Science.gov (United States)

    Mahapatra, Cecon T; Damayanti, Nur P; Guffey, Samuel C; Serafin, Jennifer S; Irudayaraj, Joseph; Sepúlveda, Maria S

    2017-06-01

    Perfluoroalkyl and polyfluoroalkyl substances (PFASs) are synthetic fluorinated compounds that are highly bioaccumulative and persistent organic pollutants. Perfluorooctanoic acid (PFOA), an eight-carbon chain perfluorinated carboxylic acid, was used heavily for the production of fluoropolymers, but concerns have led to its replacement by shorter carbon chain homologues such as perfluorohexanoic acid (PFHxA) and perfluorobutanoic acid (PFBA). However, limited toxicity data exist for these substitutes. We evaluated the toxicity of PFOA, PFHxA and PFBA on a zebrafish liver cell line and investigated the effects of exposure on cell metabolism. Gross toxicity after 96 h of exposure was highest for PFOA and PFO - , while PFHxA and PFBA exhibited lower toxicity. Although the structural similarity of these compounds to fatty acids suggests the possibility of interference with the transport and metabolism of lipids, we could not detect any differential expression of peroxisome proliferator-activated receptor (ppar-α, -β and -γ), fabp3 and crot genes after 96 h exposure to up to 10 ppm of the test compounds. However, we observed localized lipid droplet accumulation only in PFBA-exposed cells. To study the effects of these compounds on cell metabolism, we conducted fluorescence lifetime imaging microscopy using naturally fluorescent biomarkers, NADH and FAD. The fluorescence lifetimes of NADH and FAD and the bound/free ratio of each of these coenzymes decreased in a dose- and carbon length-dependent manner, suggesting disruption of cell metabolism. In sum, our study revealed that PFASs with shorter carbon chains are less toxic than PFOA, and that exposure to sublethal dosage of PFOA, PFHxA or PFBA affects cell metabolism. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  18. Enhancement of carboxylic acid degradation with sulfate radical generated by persulfate activation.

    Science.gov (United States)

    Criquet, J; Nebout, P; Karpel Vel Leitner, N

    2010-01-01

    The aim of this work was to investigate the generation of sulfate radical for the removal of two carboxylic acids in aqueous solution: acetic and citric acids. From photochemical and radiolytic processes, kinetics of the degradation of these two carboxylic acids was studied as a function of the pH of the solution. It was shown that the maximum of acetic acid degradation occurred at pH 5. Above this pH, competitive reactions with the carbon mineralized inhibit the reaction of with the solute. In the case of citric acid, pH has only a little effect on the kinetic of citric acid degradation. The determination of mineralization yields shows several differences depending on carboxylic acids and pH. The degradation of both carboxylic acids was also studied in the radiolysis process whether with or without persulfate addition. A comparison of the processes of sulfate radical production is presented.

  19. Structural and thermal properties of carboxylic acid functionalized polythiophenes

    Directory of Open Access Journals (Sweden)

    Ariane de França Mescoloto

    2014-01-01

    Full Text Available Polythiophenes functionalized with polar groups at the end of side-chain have emerged as an alternative method to obtain good compatibility between this class of conjugated polymers and electron acceptor compounds. The aim is to prevent phase segregation and to improve the efficiency of the polythiophene technological devices. However, homopolymers synthesized from thiophene rings with high polar groups at the end of the side-chain, such as hydroxyl and carboxylic acid groups, are poorly soluble in common volatile organic solvents. We report on a systematic preparation of copolymers of 3-hexylthiophene (HT and thiophene-3-acetic acid (TAA, using different feed ratios. The chemical structures of the copolymers were confirmed by FTIR and ¹H-NMR. The TAA content in these copolymers were 33, 38 and 54 mol %. HPSEC results did not show any remarkable correlation with TAA contents in the copolymers. In contrast, the thermal analyses showed a decrease in the thermal stability and an increase in rigidity of their backbones, for the copolymers with high amounts of TAA. The solubility and optical property of copolymers were also related to the TAA contents. Thus, the properties of these copolymers can be modulated by a simple control of feed ratio of TAA in the copolymerization.

  20. Effectiveness of carboxylic acids from Pichia membranifaciens against coffee rust

    Directory of Open Access Journals (Sweden)

    Rosa Laura Andrade Melchor

    Full Text Available ABSTRACT Coffee rust is a fungal disease that has affected every coffee-producing region in the world. Given that the effectivity of the protectant and systemic fungicides applied routinely to control the spread of the causative agent of the disease (Hemileia vastatrix has gradually diminished, besides are harmful to mammals and ecosystems, the objective of this work was to search for a mixture of harmless natural compounds with the potential to be applied in the field. So, a yeast strain producing a battery of long-chain carboxylic acids (CA with fungicide properties was isolated from soil of coffee crop and identified as Pichia membranifaciens by ITS sequencing. Culture conditions of the yeast were optimized and the CA in the solution were characterized by Gas Chromatography-Mass Spectrometry (GC-MS as ethyl formate (55.5 g L-1, octadecenoic acid (3.5 g L-1, propionic acid (7.2 g L-1, 3-(octadecanoyl-propionic acid (7.2 g L-1 and methyl acetate (8.4 g L-1. Randomized field studies were conducted in three different locations in Chiapas, México. Five treatments were tested including three concentrations of the CA solution (389, 584 and 778 ppm and copper oxychloride (5 000 ppm as conventional control. The initial coffee rust incidence averages varied between sites: Maravillas (3-9%, Santo Domingo (10-16% and Búcaro (16-22%. The treatments of CA solution proved to be effective at slowing down the progress of the rust disease even for the sites where initial incidence was high. Likewise, the CA solution reduced the viability of H. vastatrix spores, as assessed by fluorescence microscopy.

  1. Chiral metal-organic frameworks bearing free carboxylic acids for organocatalyst encapsulation.

    Science.gov (United States)

    Liu, Yan; Xi, Xiaobing; Ye, Chengcheng; Gong, Tengfei; Yang, Zhiwei; Cui, Yong

    2014-12-08

    Two chiral carboxylic acid functionalized micro- and mesoporous metal-organic frameworks (MOFs) are constructed by the stepwise assembly of triple-stranded heptametallic helicates with six carboxylic acid groups. The mesoporous MOF with permanent porosity functions as a host for encapsulation of an enantiopure organic amine catalyst by combining carboxylic acids and chiral amines in situ through acid-base interactions. The organocatalyst-loaded framework is shown to be an efficient and recyclable heterogeneous catalyst for the asymmetric direct aldol reactions with significantly enhanced stereoselectivity in relative to the homogeneous organocatalyst. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. High-level production of C-11-carboxyl-labeled amino acids

    International Nuclear Information System (INIS)

    Washburn, L.C.; Sun, T.T.; Byrd, B.L.; Hayes, R.L.; Butler, T.A.; Callahan, A.P.

    1979-01-01

    Carbon-11-labeled amino acids have significant potential as agents for positron tomographic functional imaging. We have developed a rapid, high-temperature, high-pressure modification of the Buecherer--Strecker amino acid synthesis and found it to be quite general for the production of C-11-carboxyl-labeled neutral amino acids. Production of C-11-carboxyl-labeled DL-tryptophan requires certain modifications in the procedure. Twelve different amino acids have been produced to date by this technique. Synthesis and chromatographic purification require approximately 40 min, and C-11-carboxyl-labeled amino acids have been produced in yields of up to 425 mCi. Two C-11-carboxyl-labeled amino acids are being investigated clinically for tumor scanning and two others for pancreatic imaging. Over 120 batches of the various agents have been produced for clinical use over a three-year period

  3. Potentiometric studies on mixed-ligand chelates of uranyl ion with carboxylic acid phenolic acids

    International Nuclear Information System (INIS)

    Bandiwadekar, S.P.; Chavar, A.M.

    1988-01-01

    Mixed ligand complexes of UO 2 2+ with bidentate carboxylic and phenolic acids have been studied potentiometrically at 30 ± 0.1degC and μ=0.2M (NaClO 4 ). 1:1 and 1:2 complexes of UO 2 2+ with phthalic acid (PTHA), maleic acid (MAE), malonic acid (MAL), quinolinic acid (QA), 5-sulphosalicylic acid (5-SSA), salicylic acid (SA), and only 1:1 complexes in the case of mandelic acid (MAD) have been detected. The formation of 1:1:1 mixed ligand complexes has been inferred from simultaneous equilibria in the present study. The values of ΔlogK, Ksub(DAL), Ksub(2LA) or Ksub(2AL) for the ternary complexes have been calculated. The stabilities of mixed ligand complexes depend on the size of the chelate ring and the stabilities of the binary complexes. (author). 15 refs

  4. Investigation of cerium salt/sulfuric acid anodizing technology for 1420 aluminum alloy

    Energy Technology Data Exchange (ETDEWEB)

    Di Li; Yue Peng Deng; Bao Lan Guo; Guo Qiang Li [Beijing Univ. of Aeronautics and Astronautics (China). Dept. of Mater. Sci. and Eng.

    2000-07-01

    In this paper, the effect of cerium addition agent on the property of anodized coating of 1420 Al alloy has been studied by corrosion experiment (immersion test and neutral salt spray test), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and measurement of polarization curves. The result show that only pitting could be observed in all corrosion tests while intergranular corrosion and exfoliation corrosion did not appear on 1420 Al-Li alloys. When organic carboxylic acid S or the cerium (IV) salt was added into sulfuric acid anodizing electrolyte separately, there was no significant improvement in corrosion resistance of anodized film. However, in the case of adding them into sulfuric acid anodizing electrolyte together, the corrosion resistance of anodized film increased greatly owing to synergistic effect. The synergistic effect may relate to the formation of cerium-organic carboxylic acid S complex compound and its effects on film growth and film structure. (orig.)

  5. Novel Regenerated Solvent Extraction Processes for the Recovery of Carboxylic Acids or Ammonia from Aqueous Solutions Part I. Regeneration of Amine-Carboxylic Acid Extracts

    Energy Technology Data Exchange (ETDEWEB)

    Poole, Loree Joanne [Univ. of California, Berkeley, CA (United States); King, C. Judson [Univ. of California, Berkeley, CA (United States)

    1990-03-01

    Two novel regenerated solvent extraction processes are examined. The first process has the potential to reduce the energy costs inherent in the recovery of low-volatility carboxylic acids from dilute aqueous solutions. The second process has the potential for reducing the energy costs required for separate recovery of ammonia and acid gases (e.g. CO2 and H2S) from industrial sour waters. The recovery of carboxylic acids from dilute aqueous solution can be achieved by extraction with tertiary amines. An approach for regeneration and product recovery from such extracts is to back-extract the carboxylic acid with a water-soluble, volatile tertiary amine, such as trimethylamine. The resulting trimethylammonium carboxylate solution can be concentrated and thermally decomposed, yielding the product acid and the volatile amine for recycle. Experimental work was performed with lactic acid, succinic acid, and fumaric acid. Equilibrium data show near-stoichiometric recovery of the carboxylic acids from an organic solution of Alamine 336 into aqueous solutions of trimethylamine. For fumaric and succinic acids, partial evaporation of the aqueous back extract decomposes the carboxylate and yields the acid product in crystalline form. The decomposition of aqueous solutions of trimethylammonium lactates was not carried out to completion, due to the high water solubility of lactic acid and the tendency of the acid to self-associate. The separate recovery of ammonia and acid gases from sour waters can be achieved by combining steam-stripping of the acid gases with simultaneous removal of ammonia by extraction with a liquid cation exchanger. The use of di-2,4,4-trimethylpentyl phosphinic acid as the liquid cation exchanger is explored in this work. Batch extraction experiments were carried out to measure the equilibrium distribution ratio of ammonia between an aqueous buffer solution and an organic solution of the phosphinic acid (0.2N) in Norpar 12. The

  6. The effects of borate minerals on the synthesis of nucleic acid bases, amino acids and biogenic carboxylic acids from formamide.

    Science.gov (United States)

    Saladino, Raffaele; Barontini, Maurizio; Cossetti, Cristina; Di Mauro, Ernesto; Crestini, Claudia

    2011-08-01

    The thermal condensation of formamide in the presence of mineral borates is reported. The products afforded are precursors of nucleic acids, amino acids derivatives and carboxylic acids. The efficiency and the selectivity of the reaction was studied in relation to the elemental composition of the 18 minerals analyzed. The possibility of synthesizing at the same time building blocks of both genetic and metabolic apparatuses, along with the production of amino acids, highlights the interest of the formamide/borate system in prebiotic chemistry.

  7. Biosynthesis of quinoxaline antibiotics: Purification and characterization of the quinoxaline-2-carboxylic acid activating enzyme from Streptomyces triostinicus

    International Nuclear Information System (INIS)

    Glund, K.; Schlumbohm, W.; Bapat, M.; Keller, U.

    1990-01-01

    A quinoxaline-2-carboxylic acid activating enzyme was purified to homogeneity from triostin-producing Streptomyces triostinicus. It could also be purified from quinomycin-producing Streptomyces echinatus. Triostins and quinomycins are peptide lactones that contain quinoxaline-2-carboxylic acid as chromophoric moiety. The enzyme catalyzes the ATP-pyrophosphate exchange reaction dependent on quinoxaline-2-carboxylic acid and the formation of the corresponding adenylate. Besides quinoxaline-2-carboxylic acid, the enzyme also catalyzes the formation of adenylates from quinoline-2-carboxylic acid and thieno[3,2-b]pyridine-5-carboxylic acid. No adenylates were seen from quinoline-3-carboxylic acid, quinoline-4-carboxylic acid, pyridine-2-carboxylic acid, and 2-pyrazinecarboxylic acid. Previous work revealed that quinoline-2-carboxylic acid and thieno[3,2-b]pyridine-5-carboxylic acid became efficiently incorporated into the corresponding quinoxaline antibiotic analogues in vivo. Together with the data described here, this suggests that the enzyme is part of the quinoxaline antibiotics synthesizing enzyme system. The enzyme displays a native molecular weight of 42,000, whereas in its denatured form it is a polypeptide of Mr 52,000-53,000. It resembles in its behavior actinomycin synthetase I, the chromophore activating enzyme involved in actinomycin biosynthesis

  8. Hepatic Metabolism of Perfluorinated Carboxylic Acids and Polychlorotrifluoroethylene: A Nuclear Magnetic Resonance Investigation in vito

    Science.gov (United States)

    1994-01-06

    L. Narayanan. and B. M. Jamot. ’Effects of Peulluoro-n- octanoic Acid , Perfluoro-n-decanoic Acid , and Clofibrate on Hepatic Phosphorus Metabolism in...pathways and examined the impact of perfluorocarboxylic acid exposure. This investigative strategy will delineate the metabolic effices exerted by...Perfluorinated Carboxylic Acids and Polychlorotrifluoroethylene: A Nuclear Magnetic Resonance Investigation in Vivo Principal Investigator: Nicholas V. Reo

  9. Phase behavior and micellar properties of carboxylic acid end group modified pluronic surfactants

    NARCIS (Netherlands)

    Custers, J.P.A.; Broeke, van den L.J.P.; Keurentjes, J.T.F.

    2007-01-01

    The micellar behavior of three different carboxylic acid end standing (CAE) surfactants has been characterized using conductometry, differential scanning calorimetry, isothermal titration calorimetry, and dynamic light scattering. The CAE surfactants are modified high molecular weight Pluronic

  10. Pyrazole carboxamides and carboxylic acids as protein kinase inhibitors in aberrant eukaryotic signal transduction

    DEFF Research Database (Denmark)

    Persson, Tobias; Yde, Christina W.; Rasmussen, Jakob Ewald

    2007-01-01

    Densely functionalised pyrazole carboxamides and carboxylic acids were synthesised in an expedient manner through saponification and transamidation, respectively, of ester-functionalised pyrazoles. This synthetic protocol allowed for three diversifying steps in which appendages on the pyrazole...

  11. Versatile Multicomponent Reaction Macrocycle Synthesis Using α-Isocyano-ω-carboxylic Acids

    NARCIS (Netherlands)

    Liao, George P; Abdelraheem, Eman M M; Neochoritis, Constantinos G; Kurpiewska, Katarzyna; Kalinowska-Tłuścik, Justyna; McGowan, David C; Dömling, Alexander

    2015-01-01

    The direct macrocycle synthesis of α-isocyano-ω-carboxylic acids via an Ugi multicomponent reaction is introduced. This multicomponent reaction (MCR) protocol differs by being especially short, convergent, and versatile, giving access to 12-22 membered rings.

  12. Direct enantioselective conjugate addition of carboxylic acids with chiral lithium amides as traceless auxiliaries.

    Science.gov (United States)

    Lu, Ping; Jackson, Jeffrey J; Eickhoff, John A; Zakarian, Armen

    2015-01-21

    Michael addition is a premier synthetic method for carbon-carbon and carbon-heteroatom bond formation. Using chiral dilithium amides as traceless auxiliaries, we report the direct enantioselective Michael addition of carboxylic acids. A free carboxyl group in the product provides versatility for further functionalization, and the chiral reagent can be readily recovered by extraction with aqueous acid. The method has been applied in the enantioselective total synthesis of the purported structure of pulveraven B.

  13. Direct Enantioselective Conjugate Addition of Carboxylic Acids with Chiral Lithium Amides as Traceless Auxiliaries

    Science.gov (United States)

    2016-01-01

    Michael addition is a premier synthetic method for carbon–carbon and carbon–heteroatom bond formation. Using chiral dilithium amides as traceless auxiliaries, we report the direct enantioselective Michael addition of carboxylic acids. A free carboxyl group in the product provides versatility for further functionalization, and the chiral reagent can be readily recovered by extraction with aqueous acid. The method has been applied in the enantioselective total synthesis of the purported structure of pulveraven B. PMID:25562717

  14. Anaerobic Fermentation for Production of Carboxylic Acids as Bulk Chemicals from Renewable Biomass.

    Science.gov (United States)

    Wang, Jufang; Lin, Meng; Xu, Mengmeng; Yang, Shang-Tian

    Biomass represents an abundant carbon-neutral renewable resource which can be converted to bulk chemicals to replace petrochemicals. Carboxylic acids have wide applications in the chemical, food, and pharmaceutical industries. This chapter provides an overview of recent advances and challenges in the industrial production of various types of carboxylic acids, including short-chain fatty acids (acetic, propionic, butyric), hydroxy acids (lactic, 3-hydroxypropionic), dicarboxylic acids (succinic, malic, fumaric, itaconic, adipic, muconic, glucaric), and others (acrylic, citric, gluconic, pyruvic) by anaerobic fermentation. For economic production of these carboxylic acids as bulk chemicals, the fermentation process must have a sufficiently high product titer, productivity and yield, and low impurity acid byproducts to compete with their petrochemical counterparts. System metabolic engineering offers the tools needed to develop novel strains that can meet these process requirements for converting biomass feedstock to the desirable product.

  15. Ru(II)-Catalyzed Oxidative Heck-Type Olefination of Aromatic Carboxylic Acids with Styrenes through Carboxylate-Assisted C-H Bond Activation.

    Science.gov (United States)

    Dana, Suman; Mandal, Anup; Sahoo, Harekrishna; Mallik, Sumitava; Grandhi, Gowri Sankar; Baidya, Mahiuddin

    2018-02-02

    A straightforward synthesis of 2-styrylbenzoic acids from aryl carboxylic acids is disclosed through a carboxylate-assisted coupling under Ru(II) catalysis. This protocol is simple and exhibits broad scope with high tolerance of common organic functional groups, providing good to excellent yields of diverse olefinated products. The efficacy of this protocol has been showcased through sequential syntheses of isochromanone, isocoumarin, and formal synthesis of anacardic acid derivative in good yields.

  16. Adsorption Equilibrium Equation of Carboxylic Acids on Anion-Exchange Resins in Water.

    Science.gov (United States)

    Kanazawa, Nobuhiro; Urano, Kohei; Kokado, Naohiro; Urushigawa, Yoshikuni

    2001-06-01

    The adsorption of propionic acid and benzoic acid on anion-exchange resins was analyzed, and an adsorption equilibrium equation of carboxylic acids was proposed. The adsorption of carboxylic acids on the anion-exchange resins was considered to be the sum of the physical adsorption of the molecule and the ion-exchange adsorption of the ion, which were independent of each other. For the physical adsorption of carboxylic acids, it was conformed to the Freundlich equation. For the ion-exchange adsorption of carboxylate ions, the equilibrium equation corresponded well with the experimental results for wide ranges of concentration and pH. The equation contains a selectivity coefficient S(A)(Cl) for the chloride ion versus the carboxylate ion, which was considered essentially a constant. The influent of the bicarbonate ion from carbon dioxide in air could also be expressed by the additional equilibrium equation with the selectivity coefficient S(HCO(3))(Cl) for the chloride ion versus the bicarbonate ion. Consequently, an adsorption equilibrium equation can estimate the equilibrium adsorption amounts. Even the effect of a coexisting bicarbonate ion is inconsequential when the parameters of the Freundlich isotherm equation and the selectivity coefficients of the carboxylate ion and the bicarbonate ion in each resin are determined in advance. Copyright 2001 Academic Press.

  17. Thermal stability of carboxylic acid functionality in coal; Sekitanchu ni sonzaisuru karubokishiruki no netsubunkai kyodo

    Energy Technology Data Exchange (ETDEWEB)

    Tsutsumi, Y.; Aida, T. [Kinki University, Osaka (Japan). Faculty of Engineering

    1996-10-28

    Carboxyl in coal was focused in discussing its pyrolytic behavior while tracking change of its absolute amount relative to the heating temperatures. A total of four kinds of coals, consisting of two kinds brown coals, sub-bituminous coal and bituminous coal were used. Change in the absolute amount of carboxyl due to heating varies with coalification degree. Decomposition starts in the bituminous coal from around 300{degree}C, and is rapidly accelerated when 400{degree}C is exceeded. Carboxyls in brown coals exist two to three times as much as those in bituminous and sub-bituminous coals, of which 40% is decomposed at a temperature as low as about 300{degree}C. Their pyrolytic behavior at temperatures higher than 400{degree}C resembles that of the bituminous coal. Carboxyls consist of those easy to decompose and difficult to decompose. Aromatic and aliphatic carboxylic acids with simple structure are stable at temperatures lower than 300{degree}C, and decompose abruptly from about 400{degree}C, hence their behavior resembles that of carboxyls in bituminous and sub-bituminous coals. Structure of low-temperature decomposing carboxyls in brown coals is not known, but it is assumed that humic acid originated from natural materials remains in the structure. 4 refs., 3 figs., 1 tab.

  18. Enhanced detection of amino acids in hydrophilic interaction chromatography electrospray tandem mass spectrometry with carboxylic acids as mobile phase additives.

    Science.gov (United States)

    Yin, Dengyang; Hu, Xunxiu; Liu, Dantong; Du, Wencheng; Wang, Haibo; Guo, Mengzhe; Tang, Daoquan

    2017-06-01

    Liquid chromatography coupled with mass spectrometry technique has been widely used in the analysis of biological targets such as amino acids, peptides, and proteins. In this work, eight common single carboxylic acids or diacids, which contain different pKa have been investigated as the additives to the analysis of amino acids. As the results, carboxylic acid additive can improve the signal intensity of acidity amino acids such as Asp and Glu and the chromatographic separation of basic amino acids such as Arg, His, and Lys. In particular, the diacids have better performance than single acids. The proposed mechanism is that the diacid has hydrogen bond interaction with amino acids to reduce their polarity/amphiprotic characteristics. Besides, oxalic acid has been found having better enhancement than phthalic acid by overall consideration. Therefore, we successfully quantified the 15 amino acids in Sepia bulk pharmaceutical chemical by using oxalic acid as the additive.

  19. Hepatic Metabolism of Perfluorinated Carboxylic Acids: A Nuclear Magnetic Resonance Investigation in Vivo

    Science.gov (United States)

    1995-01-17

    Reo, C. M. Goecke, L. Narayanan, and B. M. Jarnot. "Effects of Perfluoro-n- octanoic Acid , Perfluoro-n-decanoic Acid , and Clofibrate on Hepatic...SUBTITLE 7C 5. FUNDING NUMBERS" Hepatic Metabolism of Perfluorinated Carboxylic Acids : A Nuclear Magnetic Resonance Investigation in Vivo G-AFOSR-90-0148 6...octanoic acid (PFOA) and perfluoro-n-decanoic acid (PFDA). These Air Force chemicals belong to a class of CU’. compounds known as peroxisome

  20. 2-Oxo-1,2-dihydroquinoline-4-carboxylic acid monohydrate

    Directory of Open Access Journals (Sweden)

    Yassir Filali Baba

    2016-06-01

    Full Text Available In the title compound, C10H7NO3·H2O, O—H...O hydrogen bonds involving the carboxyl groups, the keto groups and the lattice water molecules form stepped sheets approximately parallel to {010} which are tied together by pairwise N—H...O interactions. The asymmetric unit contains two independent quinolone derivatives and two water molecules, one of which is disordered over two positions, of equal occupancy.

  1. 21 CFR 172.863 - Salts of fatty acids.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Salts of fatty acids. 172.863 Section 172.863 Food... Multipurpose Additives § 172.863 Salts of fatty acids. The food additive salts of fatty acids may be safely..., magnesium, potassium, and sodium salts of the fatty acids conforming with § 172.860 and/or oleic acid...

  2. Bienzymatic Acetylcholinesterase and Choline Oxidase Immobilized Biosensor Based on a Phenyl Carboxylic Acid-Grafted Multiwalled Carbon Nanotube

    Directory of Open Access Journals (Sweden)

    So-Ra Lee

    2014-01-01

    Full Text Available Bienzymatic acetylcholinesterase (AChE and choline oxidase (ChOx immobilized biosensor based on a phenyl carboxylic acid-grafted multiwalled carbon nanotube (MWNT modified glass carbon electrode (GCE and carbon-screen printed electrode (SPE was fabricated for acetylcholine detection in human blood samples. Phenyl carboxylic acid-modified MWNT supports were prepared by electrochemical polymerization of 4-carboxyphenyl diazonium salts, which were synthesized by an amine group and sodium nitrite, on the surface of the MWNT-modified GCE and SPE in 0.1 M PBS. The successful fabrication of the AChE-ChOx-immobilized biosensor was confirmed via scanning electron microscopy (SEM, X-ray photoelectron spectroscopy (XPS, electrochemical impedance spectroscopy (EIS, and cyclic voltammetry (CV. The sensing range of the biosensor based on a GCE and SPE was 1.0~10 μM and 10~100 μM, respectively. The interfering effect of 0.1 M L-ascorbic acid, 0.1 M L-cysteine, and 0.1 M uric acid to 0.1 M acetylcholine was 3.00%, 9.00%, and 3.00%, respectively. Acetylcholine in a human blood sample was detected by the AChE-ChOx-immobilized biosensor.

  3. A Concise Synthesis and the Antibacterial Activity of 5,6-Dimethoxynaphthalene-2-carboxylic Acid

    OpenAIRE

    GÖKSU, Süleyman; UĞUZ, Metin Tansu

    2014-01-01

    5,6-Dimethoxynaphthalene-2-carboxylic acid was synthesized in 7 steps and with an overall yield of 46%. Bromination of 2-naphthol, and methylation with dimethyl sulfate followed by Friedel-Crafts acylation with AcCl gave 2-acetyl-5-bromo-6-methoxynaphthalene. 2-Acetyl-5-bromo-6-methoxynaphthalene was converted to 5-bromo-6- methoxynaphthalene-2-carboxylic acid by a haloform reaction. The esterification of the acid with methanol, methoxylation with NaOCH3 in the presence of CuI and s...

  4. Phosphorescent emissions of phosphine copper(I) complexes bearing 8-hydroxyquinoline carboxylic acid analogue ligands

    Energy Technology Data Exchange (ETDEWEB)

    Małecki, Jan G., E-mail: gmalecki@us.edu.pl [Department of Crystallography, Institute of Chemistry, University of Silesia, Szkolna 9 street, 40-006 Katowice (Poland); Łakomska, Iwona, E-mail: iwolak@chem.umk.pl [Department of Chemistry, Nicolaus Copernicus University, Toruń (Poland); Maroń, Anna [Department of Crystallography, Institute of Chemistry, University of Silesia, Szkolna 9 street, 40-006 Katowice (Poland); Szala, Marcin [Institute of Chemistry, University of Silesia, ul. Szkolna 9, 40-006 Katowice (Poland); Fandzloch, Marzena [Department of Chemistry, Nicolaus Copernicus University, Toruń (Poland); Nycz, Jacek E., E-mail: jacek.nycz@us.edu.pl [Institute of Chemistry, University of Silesia, ul. Szkolna 9, 40-006 Katowice (Poland)

    2015-05-15

    The pseudotetrahedral complexes of [Cu(PPh{sub 3}){sub 2}(L)], where L=8-hydroxy-2-methylquinoline-7-carboxylic acid (1), 8-hydroxy-2,5-dimethylquinoline-7-carboxylic acid (2) or 5-chloro-8-hydroxy-2-methylquinoline-7-carboxylic acid (3) have been synthesized and structurally characterized by X-ray crystallography. Their properties have been examined through combinations of IR, NMR, electronic absorption spectroscopy and cyclic voltammetry. The complexes exhibit extraordinary photophysical properties. Complex (1) in solid state exhibits an emission quantum yield of 4.67% and an excited life time of 1.88 ms (frozen DCM solution up to 6.7 ms). When dissolved in a coordinating solvent (acetonitrile) the charge transfer emission was quenched on a microsecond scale. - Highlights: • Synthesis of copper(I) complexes with 8-hydroxyquinoline carboxylic acid ligands. • Very long lived phosphorescent copper(I) complexes. • [Cu(PPh{sub 3}){sub 2}(L)] where L=8-hydroxy-2-methylquinoline-7-carboxylic acid luminesce in the solid state exhibits extremely long lifetime on millisecond scale (1.9 ms). • In frozen MeOH:EtOH solution lifetime increases to 7 ms. • Quantum efficiency equal to 4.7%.

  5. Transition Metal Catalyzed Synthesis of Carboxylic Acids, Imines, and Biaryls

    DEFF Research Database (Denmark)

    Santilli, Carola; Madsen, Robert

    the carboxylate.  Manganese catalyzed radical Kumada-type reaction between aryl halidesand aryl Grignard reagents. The reaction between aryl halides and aryl Grignard reagents catalyzed by MnCl2 has been extended to several methyl-substituted aryl iodide reagents byperforming the reaction at 120 ˚C in a microwave...... oven (Scheme ii). A limitation of the heterocoupling process is the concomitant dehalogenation of the aryl halide and homocoupling of the Grignard reagent leading low to moderate yields of the desired heterocoupling product. The mechanism of the cross-coupling process was investigated by performing two...

  6. Sodium borohydride reduction of aromatic carboxylic acids via ...

    Indian Academy of Sciences (India)

    Unknown

    using a sodium borohydride–THF–methanol system. The alcohols ... rature using ethanol or methanol as solvent. Although, .... acids, phenylacetic acids, phenylpropanoic acid and cinnamic ... excess of reagent in water or alcohol, involved a.

  7. Synthesis and HPLC evaluation of carboxylic acid phases on a hydride surface.

    Science.gov (United States)

    Pesek, Joseph J; Matyska, Maria T; Gangakhedkar, Surekha; Siddiq, Rukhsana

    2006-04-01

    Three organic moieties containing carboxylic acid functional groups are attached to a particulate silica surface through silanization/hydrosilation. Two compounds (undecylenic acid and 10-undecynoic acid) have 11 carbon chains and the other is a five-carbon acid (pentenoic acid). Bonding is confirmed through carbon elemental analysis, diffuse reflectance infrared fourier transform spectroscopy, and carbon-13 and silicon-29 CP-MAS NMR spectroscopy. The bonded phases are tested by HPLC using PTH amino acids, nucleic acids, theophylline-related compounds, anilines, benzoic acid compounds, choline, and tobramycin. The latter two compounds are used to investigate the aqueous normal phase properties of the three bonded materials.

  8. Hepatic Metabolism of Perfluorinated Carboxylic Acids and Polychlorotrifluoroethylene: A Nuclear Magnetic Resonance Investigation in Vivo

    Science.gov (United States)

    1994-01-05

    Goecke, L. Narayanan, and B. M. Jarnot. "Effects of Perfluoro-n- octanoic Acid , Perfluoro-n-decanoic Acid , and Clofibrate on Hepatic Phosphorus L...Carboxylic Acids and 4Polychiorotrifluoroethylene: A Nuclear Magnetic Resonance G-AFOSR-90-0148 Investigation in Vivo ,IIC 6. AUTHOR(S a Nicholas V. Reo...Maxim um 200 words) This report outlines our research progress regarding toxicological investigations of perifluoro- n-octanoic acid (PFOA) and

  9. The investigation of the reactions of some pyrazole-3-carboxylic acids with various diamines and diols

    Directory of Open Access Journals (Sweden)

    Rahmi Kasımoğulları

    2012-06-01

    Full Text Available In this study, some new derivatives were synthesized of 4-benzoyl-1-(3-nitrophenyl-5-phenyl-1H-pyrazole-3-carboxylic acid (1 and 4-(ethoxycarbonyl-1-(3-nitrophenyl-5-phenyl-1H-pyrazole-3-carboxylic acid (2 that they were pyrazole carboxylic acid derivatives. Firstly, 1 and 2 reacted with SOCl2 to transform them into acyl chlorides (3, 4. Then various bis-carboxamide derivatives (5–8 were obtained from the reaction of 3 and 4 with various diamines and also a ;#946;-hydroxy ester (9 derivative was obtained from the reaction of 3 with ethylene glycol. The structures of synthesized compounds were elucidated with using FT-IR, 1H NMR, 13C NMR and elemental analysis methods.

  10. Carboxylic acid effects on the size and catalytic activity of magnetite nanoparticles.

    Science.gov (United States)

    Hosseini-Monfared, Hassan; Parchegani, Fatemeh; Alavi, Sohaila

    2015-01-01

    Magnetite nanoparticles (Fe3O4-NPs) were successfully synthesized in diethylene glycol in the presence of carboxylic acids. They were characterized using XRD, SEM and FTIR. Carboxylic acid plays a critical role in determining the morphology, particle size and size distribution of the resulting particles. The results show that as-prepared magnetite nanoparticles are monodisperse and highly crystalline. The nanoparticles can be easily dispersed in aqueous media and other polar solvents due to coated by a layer of hydrophilic polyol and carboxylic acid ligands in situ. Easily prepared Fe3O4-NPs have been shown to be an active, recyclable, and highly selective catalyst for the epoxidation of cyclic olefins with aqueous 30% H2O2. Copyright © 2014 Elsevier Inc. All rights reserved.

  11. 21 CFR 573.914 - Salts of volatile fatty acids.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Salts of volatile fatty acids. 573.914 Section 573... Food Additive Listing § 573.914 Salts of volatile fatty acids. (a) Identity. The food additive is a... contains ammonium or calcium salts of volatile fatty acids and shall conform to the following...

  12. [Chloroquine analogues from benzofuro- and benzothieno[3,2-b]-4-pyridone-2-carboxylic acid esters].

    Science.gov (United States)

    Gölitzer, K; Meyer, H; Jomaa, H; Wiesner, J

    2004-08-01

    The amides 7 were synthesized from the annulated methyl 4-pyridone-2-carboxylates 4 via the carboxylic acids 5 and their acid chlorides by reacting with the novaldiamine base 6. The alcohol 8b, obtained from DIBAH reduction of the ester 4b, was transformed to the chloromethyl derivative 9 which reacted with 6 and 18-crown-6 leading to the 2-novaldiaminomethyl-4-pyridone 10. Compound 10 was obtained with higher yield from DIBAH reduction of the amide 7b. The substances 7 and 10 were inactive when tested against the chloroquine resistant Plasmodium falciparum strain Dd2.

  13. Silver-Catalyzed Dehydrogenative Synthesis of Carboxylic Acids from Primary Alcohols

    DEFF Research Database (Denmark)

    Ghalehshahi, Hajar Golshadi; Madsen, Robert

    2017-01-01

    A simple silver-catalyzed protocol has been developed for the acceptorless dehydrogenation of primary alcohols into carboxylic acids and hydrogen gas. The procedure uses 2.5 % Ag2 CO3 and 2.5-3 equiv of KOH in refluxing mesitylene to afford the potassium carboxylate which is then converted...... into the acid with HCl. The reaction can be applied to a variety of benzylic and aliphatic primary alcohols with alkyl and ether substituents, and in some cases halide, olefin, and ester functionalities are also compatible with the reaction conditions. The dehydrogenation is believed to be catalyzed by silver...

  14. Simple quantification of surface carboxylic acids on chemically oxidized multi-walled carbon nanotubes

    Science.gov (United States)

    Gong, Hyejin; Kim, Seong-Taek; Lee, Jong Doo; Yim, Sanggyu

    2013-02-01

    The surface of multi-walled carbon nanotube (MWCNT) was chemically oxidized using nitric acid and sulfuric-nitric acid mixtures. Thermogravimetric analysis, transmission electron microscopy and infrared spectroscopy revealed that the use of acid mixtures led to higher degree of oxidation. More quantitative identification of surface carboxylic acids was carried out using X-ray photoelectron spectroscopy (XPS) and acid-base titration. However, these techniques are costly and require very long analysis times to promptly respond to the extent of the reaction. We propose a much simpler method using pH measurements and pre-determined pKa value in order to estimate the concentration of carboxylic acids on the oxidized MWCNT surfaces. The results from this technique were consistent with those obtained from XPS and titration, and it is expected that this simple quantification method can provide a cheap and fast way to monitor and control the oxidation reaction of MWCNT.

  15. Precipitation stripping of neodymium from carboxylate extractant with aqueous oxalic acid solutions

    International Nuclear Information System (INIS)

    Konishi, Yasuhiro; Asai, Satoru; Murai, Tetuya

    1993-01-01

    This paper describes a precipitation stripping method in which neodymium ions are stripped from carboxylate extractant in organic solvent and simultaneously precipitated with aqueous oxalic acid solution. For the single-stage process, a quantitative criterion for precipitating oxalate powders was derived theoretically, and stripping experiments were done under the precipitation conditions. The resultant precipitates were neodymium oxalate, which is completely free from contamination by the carboxylate extractant and the organic solvent. The overall rate of stripping was controlled by the transfer of neodymium carboxylate in the organic solution, indicating that the presence of oxalic acid in the aqueous phase has no effect on the stripping rate. These findings demonstrate the feasibility of combining the conventional stripping and precipitation stages in a solvent extraction process for separation and purification of rare earths

  16. Synthesis of 2-phenyl- and 2,3-diphenyl-quinolin-4-carboxylic acid derivatives

    International Nuclear Information System (INIS)

    Elhadi, S. A.

    2004-09-01

    Quinolin derivatives are a group of compounds known to possess a wide range of biological activities. The chemistry of quinolines together with their corresponding aldehydes were dealt with in chapter one of this study. Special emphasis was given to the chemistry of benzaldehyde. Twenty five 2-phenyl- and 2,3-diphenyl-quinolin-4-carboxylic acid derivatives together with their corresponding intermediates were prepared in this work. Basically, the synthetic design of these compounds arise from the appropriate disconnections of the target 2-phenyl and 2,3-diphenyl-quinolin-4-carboxylic acids. The retro synthesis analysis of these compounds reveals pyruvic acid, aromatic amine and benzaldehyde or phenyl pyruvic acid, aromatic amine and benzaldehyde as possible logical precursors for 2-phenyl-and 2,3-diphenyl- quinoline-4-carboxylic acids respectively. The purity and identities of the synthesized compounds were elucidated through chromatographic and spectroscopic techniques. The compounds were heavily subjected to spectroscopic analysis (UV, IR, GC/MS, 1 H-and 13 C- NMR). The appropriate disconnections and the mechanisms of the corresponding reactions were given and discussed in chapter three. The spectral data were interpreted and correlated with the target structures. The prepared 2-phenyl- and 2,3-diphenyl-quinoline-4-carboxylic acid derivatives were screened for their antibacterial activity. The compounds were tested against the standard bacterial organisms B. subtilis, S. aureus, E. coli and P. vulgaris. Some of these compounds were devoid of antibacterial activity against S. aureus and P. vulgaris, while others showed moderate activity. All of the tested compounds showed an activity against B. subtilis and E. coli. 2,3-diphenyl -6-sulphanilamide-quinolin-4-carboxylic acid showed the highest activity against the four standard tested organisms.(Author)

  17. Synthesis of 2-phenyl- and 2,3-diphenyl-quinolin-4-carboxylic acid derivatives

    Energy Technology Data Exchange (ETDEWEB)

    Elhadi, S A [Department of Chemistry, Faculty of Education, University of Khartoum, Khartoum (Sudan)

    2004-09-01

    Quinolin derivatives are a group of compounds known to possess a wide range of biological activities. The chemistry of quinolines together with their corresponding aldehydes were dealt with in chapter one of this study. Special emphasis was given to the chemistry of benzaldehyde. Twenty five 2-phenyl- and 2,3-diphenyl-quinolin-4-carboxylic acid derivatives together with their corresponding intermediates were prepared in this work. Basically, the synthetic design of these compounds arise from the appropriate disconnections of the target 2-phenyl and 2,3-diphenyl-quinolin-4-carboxylic acids. The retro synthesis analysis of these compounds reveals pyruvic acid, aromatic amine and benzaldehyde or phenyl pyruvic acid, aromatic amine and benzaldehyde as possible logical precursors for 2-phenyl-and 2,3-diphenyl- quinoline-4-carboxylic acids respectively. The purity and identities of the synthesized compounds were elucidated through chromatographic and spectroscopic techniques. The compounds were heavily subjected to spectroscopic analysis (UV, IR, GC/MS, {sup 1}H-and {sup 13}C- NMR). The appropriate disconnections and the mechanisms of the corresponding reactions were given and discussed in chapter three. The spectral data were interpreted and correlated with the target structures. The prepared 2-phenyl- and 2,3-diphenyl-quinoline-4-carboxylic acid derivatives were screened for their antibacterial activity. The compounds were tested against the standard bacterial organisms B. subtilis, S. aureus, E. coli and P. vulgaris. Some of these compounds were devoid of antibacterial activity against S. aureus and P. vulgaris, while others showed moderate activity. All of the tested compounds showed an activity against B. subtilis and E. coli. 2,3-diphenyl -6-sulphanilamide-quinolin-4-carboxylic acid showed the highest activity against the four standard tested organisms.(Author)

  18. Effect of carboxylic acid of periodic mesoporous organosilicas on the fructose-to-5-hydroxymethylfurfural conversion in dimethylsulfoxide systems

    Energy Technology Data Exchange (ETDEWEB)

    Dutta, Saikat; Wu, Kevin C.-W., E-mail: hmkao@cc.ncu.edu.tw, E-mail: kevinwu@ntu.edu.tw [Department of Chemical Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan (China); Kao, Hsien-Ming, E-mail: hmkao@cc.ncu.edu.tw, E-mail: kevinwu@ntu.edu.tw [Department of Chemistry, National Central University, Chung-Li 32054, Taiwan (China)

    2014-11-01

    This manuscript presents the preparation and catalytic application of highly ordered benzene bridged periodic mesoporous organosilicas (PMOs) functionalized with carboxylic acid (–COOH) group at varied density. The COOH-functionalized PMOs were synthesized by one-step condensation of 1,4-bis (triethoxysilyl) benzene and carboxylic group containing organosilane carboxyethylsilanetriol sodium salt using Brij-76 as the template. The obtained materials were characterized by a mean of methods including powder X-ray diffraction, nitrogen adsorption-desorption, scanning- and transmission electron microscopy, and {sup 13}C solid-state nuclear magnetic resonance measurements. The potentials of the obtained PMO materials with ordered mesopores were examined as solid catalysts for the chemical conversion of fructose to 5-hydroxymethylfurfural (HMF) in an organic solvent. The results showed that COOH-functionalized PMO with 10% COOH loading exhibited best results for the fructose to HMF conversion and selectivity. The high surface area, the adequate density acid functional group, and the strength of the PMO materials contributing to a promising catalytic ability were observed.

  19. Effect of carboxylic acid of periodic mesoporous organosilicas on the fructose-to-5-hydroxymethylfurfural conversion in dimethylsulfoxide systems

    International Nuclear Information System (INIS)

    Dutta, Saikat; Wu, Kevin C.-W.; Kao, Hsien-Ming

    2014-01-01

    This manuscript presents the preparation and catalytic application of highly ordered benzene bridged periodic mesoporous organosilicas (PMOs) functionalized with carboxylic acid (–COOH) group at varied density. The COOH-functionalized PMOs were synthesized by one-step condensation of 1,4-bis (triethoxysilyl) benzene and carboxylic group containing organosilane carboxyethylsilanetriol sodium salt using Brij-76 as the template. The obtained materials were characterized by a mean of methods including powder X-ray diffraction, nitrogen adsorption-desorption, scanning- and transmission electron microscopy, and 13 C solid-state nuclear magnetic resonance measurements. The potentials of the obtained PMO materials with ordered mesopores were examined as solid catalysts for the chemical conversion of fructose to 5-hydroxymethylfurfural (HMF) in an organic solvent. The results showed that COOH-functionalized PMO with 10% COOH loading exhibited best results for the fructose to HMF conversion and selectivity. The high surface area, the adequate density acid functional group, and the strength of the PMO materials contributing to a promising catalytic ability were observed

  20. Synthesis of aminocarbonyl N-acylhydrazones by a three-component reaction of isocyanides, hydrazonoyl chlorides, and carboxylic acids.

    Science.gov (United States)

    Giustiniano, Mariateresa; Meneghetti, Fiorella; Mercalli, Valentina; Varese, Monica; Giustiniano, Francesco; Novellino, Ettore; Tron, Gian Cesare

    2014-10-17

    A novel one-pot multicomponent synthesis of α-aminocarbonyl N-acylhydrazones starting from readily available hydrazonoyl chlorides, isocyanides, and carboxylic acids is reported. The strategy exploits the ability of the carboxylic acid as a third component to suppress all competing reactions between nitrile imines and isocyanides, channeling the course of the reaction toward the formation of this novel class of compounds.

  1. Solvent-Free Esterification of Carboxylic Acids Using Supported Iron Oxide Nanoparticles as an Efficient and Recoverable Catalyst

    Directory of Open Access Journals (Sweden)

    Fatemeh Rajabi

    2016-07-01

    Full Text Available Supported iron oxide nanoparticles on mesoporous materials (FeNP@SBA-15 have been successfully utilized in the esterification of a variety carboxylic acids including aromatic, aliphatic, and long-chain carboxylic acids under convenient reaction conditions. The supported catalyst could be easily recovered after reaction completion and reused several times without any loss in activity after up to 10 runs.

  2. Substituted Amides of Pyrazine-2-carboxylic acids: Synthesis and Biological Activity

    Directory of Open Access Journals (Sweden)

    Katarina Kralova

    2002-03-01

    Full Text Available Condensation of 6-chloro-, 5-tert-butyl- or 6-chloro-5-tert-butylpyrazine-2-carboxylic acid chloride with ring substituted anilines yielded a series of amides, which were tested for their in vitro antimycobacterial, antifungal and photosynthesis-inhibiting activities. The highest antituberculotic activity (72% inhibition against Mycobacterium tuberculosis and the highest lipophilicity (log P = 6.85 were shown by the 3,5-bistrifluoromethylphenyl amide of 5-tert-butyl-6-chloropyrazine-2-carboxylic acid (2o. The 3-methylphenyl amides of 6-chloro- and 5-tert-butyl-6-chloro-pyrazine-2-carboxylic acid (2d and 2f exhibited only a poor in vitro antifungal effect (MIC = 31.25-500 μmol·dm-3 against all strains tested, although the latter was the most active antialgal compound (IC50 = 0.063 mmol·dm-3. The most active inhibitor of oxygen evolution rate in spinach chloroplasts was the (3,5-bis-trifluoromethylphenylamide of 6-chloropyrazine-2-carboxylic acid (2m, IC50 = 0.026 mmol·dm-3.

  3. Optimization of polycrystalline platinum catalytic activity opposite to carboxylic acids oxidation

    International Nuclear Information System (INIS)

    Le Naour, C.; Moisy, P.; Blanc, P.; Madic, C.

    1994-01-01

    In electro nuclear industry, in the aim to reduce the quantity of wastes coming from the spent fuels reprocessing, the use of reagents as some carboxylic acids is considered: after use, these reagents are completely decomposed in gaseous products, which can be filtered and released in environment

  4. Use of technical mixtures of carboxylic acids to the extraction of silver

    International Nuclear Information System (INIS)

    Smulek, W.

    1983-01-01

    The application of technical mixtures of carboxylic acids, obtained from a Polish oil mill, to the extraction of silver, gold, and europium is described. The distribution ratio is given as a function of HNO 3 and H 2 SO 4 concentrations, extractant and metal concentrations, and nature of diluent. (author)

  5. Growth kinetics of racemic heptahelicene-2-carboxylic acid nanowires on calcite (104)

    Czech Academy of Sciences Publication Activity Database

    Einax, M.; Richter, T.; Nimmrich, M.; Rahe, P.; Stará, Irena G.; Starý, Ivo; Kühnle, A.; Maass, P.

    2016-01-01

    Roč. 145, č. 13 (2016), č. článku 134702. ISSN 0021-9606 Institutional support: RVO:61388963 Keywords : heptahelicene-2-carboxylic acid nanowires * nc-AFM * calcite * growth kinetics Subject RIV: CC - Organic Chemistry Impact factor: 2.965, year: 2016

  6. The protonation state of small carboxylic acids at the water surface from photoelectron spectroscopy

    Czech Academy of Sciences Publication Activity Database

    Ottosson, N.; Wernersson, Erik; Söderström, J.; Pokapanich, W.; Kaufmann, S.; Svensson, S.; Persson, I.; Öhrwall, G.; Björneholm, O.

    2011-01-01

    Roč. 13, č. 26 (2011), s. 12261-12267 ISSN 1463-9076 Institutional research plan: CEZ:AV0Z40550506 Keywords : water surface * carboxylic acids * photoelectron spectroscopy Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.573, year: 2011

  7. Basicity of carboxylic acids: resonance in the cation and substituent effects

    Czech Academy of Sciences Publication Activity Database

    Böhm, S.; Exner, Otto

    2005-01-01

    Roč. 29, - (2005), s. 336-342 ISSN 1144-0546 R&D Projects: GA MŠk(CZ) LN00A032 Institutional research plan: CEZ:AV0Z4055905 Keywords : basicity * carboxylic acids Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.574, year: 2005

  8. 40 CFR 721.3629 - Triethanolamine salts of fatty acids.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Triethanolamine salts of fatty acids... Substances § 721.3629 Triethanolamine salts of fatty acids. (a) Chemical substances and significant new uses subject to reporting. (1) The chemical substances identified generically as triethanolamine salts of fatty...

  9. Cesium Salts of Phosphotungstic Acid: Comparison of Surface ...

    African Journals Online (AJOL)

    NICO

    acidity and lowest solubility in reaction media in comparison with the other cesium content salts. KEYWORDS. Polyoxometalates, cesium ... insoluble salt of HPA is cesium salt of tungstophosphoric acid,. CsxH3-xPW12O40 (CsxPW), a ... of Cs2CO3, very fine particles (precipitates) were formed to make the solution milky.

  10. 40 CFR 721.5278 - Substituted naphthalenesulfonic acid, alkali salt.

    Science.gov (United States)

    2010-07-01

    ..., alkali salt. 721.5278 Section 721.5278 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.5278 Substituted naphthalenesulfonic acid, alkali salt. (a) Chemical... as a substituted naphthalenesulfonic acid, alkali salt (PMN P-95-85) is subject to reporting under...

  11. Effects of carboxylic acids on nC60 aggregate formation

    International Nuclear Information System (INIS)

    Chang Xiaojun; Vikesland, Peter J.

    2009-01-01

    The discovery that negatively charged aggregates of C 60 fullerene (nC 60 ) are stable in water has raised concerns regarding the potential environmental and health effects of these aggregates. In this work, we show that nC 60 aggregates produced by extended mixing in the presence of environmentally relevant carboxylic acids (acetic acid, tartaric acid, citric acid) have surface charge and morphologic properties that differ from those produced by extended mixing in water alone. In general, aggregates formed in the presence of these acids have a more negative surface charge and are more homogeneous than those produced in water alone. Carboxylic acid identity, solution pH, and sodium ion concentration, which are all intricately coupled, play an important role in setting the measured surface charge. Comparisons between particle sizes determined by analysis of TEM images and those obtained by dynamic light scattering (DLS) indicate that DLS results require careful evaluation when used to describe nC 60 aggregates. - The effects of carboxylic acids on the formation of nC 60 aggregates are discussed

  12. 21 CFR 172.350 - Fumaric acid and salts of fumaric acid.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Fumaric acid and salts of fumaric acid. 172.350... HUMAN CONSUMPTION Special Dietary and Nutritional Additives § 172.350 Fumaric acid and salts of fumaric acid. Fumaric acid and its calcium, ferrous, magnesium, potassium, and sodium salts may be safely used...

  13. Edge-carboxylated graphene nanoflakes from nitric acid oxidised arc-discharge material

    OpenAIRE

    NICOLOSI, VALERIA

    2010-01-01

    PUBLISHED Graphene nanoflakes (GNFs) with average diameters of 30 nm have been prepared by a single-step oxidation procedure using single-wall carbon nanotube arc-discharge material and nitric acid. The GNFs are predominately single sheets containing a small number of internal defects. The edges are decorated with primarily carboxylic acid groups which allow facile chemical functionalisation and cross-linking of the fragments using multivalent cations

  14. Use of scandium ionic associates with salicylic- or 2-phenylquinoline-4-carboxylic acid and rhodamine C

    Energy Technology Data Exchange (ETDEWEB)

    Kononenko, L.I.; Bel' tyukova, S V; Drobyazko, V N; Poluehktov, N S [AN Ukrainskoj SSR, Kiev. Inst. Obshchej i Neorganicheskoj Khimii; AN Ukrainskoj SSR, Odessa. Inst. Obshchej i Neorganicheskoj Khimii)

    1975-09-01

    With salicylic or 2-phenylquinoline-4-carboxylic acid and rhodamine C scandium forms ion associations whose benzene solutions are capable of luminescence. Optimum conditions for the formation of complexes and the composition of the complex with the ratio of Sc:acid:rhodamine C = 1:2:1 are established. A possibility of luminescence determination of scandium in the presence of rare earths is shown.

  15. Chemical states of p-boronophenylalanine in aqueous carboxylic acids and polyols

    International Nuclear Information System (INIS)

    Kobayashi, Mitsue; Kitaoka, Yoshinori

    1995-01-01

    Chemical states of p-boronophenylalanine were studied by infrared (IR) spectroscopy in aqueous carboxylic acids and in aqueous fructose. For BPA in water, the absorption band due to the B-O stretching of trigonal boron was observed, while that of tetrahedral boron was observed for BPA in aqueous oxalic acid. This means BPA forms a complex of tetrahedral boron with oxalate. It was proved that BPA also formed complexes of tetrahedral boron with citric acid as well as with fructose. No appreciable interaction was detected between BPA and maleic acid. (author)

  16. On the formation of niacin (vitamin B3) and pyridine carboxylic acids in interstellar model ices

    Energy Technology Data Exchange (ETDEWEB)

    McMurtry, Brandon M.; Turner, Andrew M.; Saito, Sean E.J.; Kaiser, Ralf I. [W. M. Keck Research Laboratory in Astrochemistry, University of Hawaii at Manoa, Honolulu, Hawaii, HI 96822 (United States); Department of Chemistry, University of Hawaii at Manoa, Honolulu, Hawaii, HI 96822 (United States)

    2016-06-15

    The formation of pyridine carboxylic acids in interstellar ice grains was simulated by electron exposures of binary pyridine (C{sub 5}H{sub 5}N)-carbon dioxide (CO{sub 2}) ice mixtures at 10 K under contamination-free ultrahigh vacuum conditions. Chemical processing of the pristine ice and subsequent warm-up phase was monitored on line and in situ via Fourier transform infrared spectroscopy to probe for the formation of new radiation induced species. In the infrared spectra of the irradiated ice, bands assigned to nicotinic acid (niacin; vitamin B3; m-C{sub 5}H{sub 4}NCOOH) along with 2,3-, 2,5-, 3,4-, and 3,5-pyridine dicarboxylic acid (C{sub 5}H{sub 3}N(COOH){sub 2}) were unambiguously identified along with the hydroxycarbonyl (HOCO) radical. Our study suggests that the reactive pathway responsible for pyridine carboxylic acids formation involves a HOCO intermediate, which forms through the reaction of suprathermal hydrogen ejected from pyridine with carbon dioxide. The newly formed pyridinyl radical may then undergo radical–radical recombination with a hydroxycarbonyl radical to form a pyridine carboxylic acid.

  17. Carboxylic acid functional group analysis using constant neutral loss scanning-mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Dron, Julien [Laboratoire de Chimie et Environnement, Marseille Universites (case 29), 3 place Victor Hugo, 13331 Marseille Cedex 3 (France)], E-mail: julien.dron@up.univ-mrs.fr; Eyglunent, Gregory; Temime-Roussel, Brice; Marchand, Nicolas; Wortham, Henri [Laboratoire de Chimie et Environnement, Marseille Universites (case 29), 3 place Victor Hugo, 13331 Marseille Cedex 3 (France)

    2007-12-12

    The present study describes the development of a new analytical technique for the functional group determination of the carboxylic moiety using atmospheric pressure chemical ionization-mass spectrometry (APCI-MS/MS) operated in the constant neutral loss scanning (CNLS) mode. Carboxylic groups were first derivatized into their corresponding methyl esters by reacting with BF{sub 3}/methanol mix and the reaction mixture was then directly injected into the APCI chamber. The loss of methanol (m/z = 32 amu) resulting from the fragmentation of the protonated methyl esters was then monitored. Applying this method together with a statistical approach to reference mixtures containing 31 different carboxylic acids at randomly calculated concentrations demonstrated its suitability for quantitative functional group measurements with relative standard deviations below 15% and a detection limit of 0.005 mmol L{sup -1}. Its applicability to environmental matrices was also shown through the determination of carboxylic acid concentrations inside atmospheric aerosol samples. To the best of our knowledge, it is the first time that the tandem mass spectrometry was successfully applied to functional group analysis, offering great perspectives in the characterization of complex mixtures which are prevailing in the field of environmental analysis as well as in the understanding of the chemical processes occurring in these matrices.

  18. Carboxylic acid functional group analysis using constant neutral loss scanning-mass spectrometry

    International Nuclear Information System (INIS)

    Dron, Julien; Eyglunent, Gregory; Temime-Roussel, Brice; Marchand, Nicolas; Wortham, Henri

    2007-01-01

    The present study describes the development of a new analytical technique for the functional group determination of the carboxylic moiety using atmospheric pressure chemical ionization-mass spectrometry (APCI-MS/MS) operated in the constant neutral loss scanning (CNLS) mode. Carboxylic groups were first derivatized into their corresponding methyl esters by reacting with BF 3 /methanol mix and the reaction mixture was then directly injected into the APCI chamber. The loss of methanol (m/z = 32 amu) resulting from the fragmentation of the protonated methyl esters was then monitored. Applying this method together with a statistical approach to reference mixtures containing 31 different carboxylic acids at randomly calculated concentrations demonstrated its suitability for quantitative functional group measurements with relative standard deviations below 15% and a detection limit of 0.005 mmol L -1 . Its applicability to environmental matrices was also shown through the determination of carboxylic acid concentrations inside atmospheric aerosol samples. To the best of our knowledge, it is the first time that the tandem mass spectrometry was successfully applied to functional group analysis, offering great perspectives in the characterization of complex mixtures which are prevailing in the field of environmental analysis as well as in the understanding of the chemical processes occurring in these matrices

  19. Measuring the concentration of carboxylic acid groups in torrefied spruce wood.

    Science.gov (United States)

    Khazraie Shoulaifar, Tooran; Demartini, Nikolai; Ivaska, Ari; Fardim, Pedro; Hupa, Mikko

    2012-11-01

    Torrefaction is moderate thermal treatment (∼200-300°C) to improve the energy density, handling and storage properties of biomass fuels. In biomass, carboxylic sites are partially responsible for its hygroscopic. These sites are degraded to varying extents during torrefaction. In this paper, we apply methylene blue sorption and potentiometric titration to measure the concentration of carboxylic acid groups in spruce wood torrefied for 30min at temperatures between 180 and 300°C. The results from both methods were applicable and the values agreed well. A decrease in the equilibrium moisture content at different humidity was also measured for the torrefied wood samples, which is in good agreement with the decrease in carboxylic acid sites. Thus both methods offer a means of directly measuring the decomposition of carboxylic groups in biomass during torrefaction as a valuable parameter in evaluating the extent of torrefaction which provides new information to the chemical changes occurring during torrefaction. Copyright © 2012 Elsevier Ltd. All rights reserved.

  20. 4-Methyl-2,2-dioxo-1H-2λ6,1-benzothiazine-3-carboxylic Acid. Peculiarities of Preparation, Structure, and Biological Properties

    Directory of Open Access Journals (Sweden)

    Igor V. Ukrainets

    2018-03-01

    Full Text Available In order to determine the regularities of the structure–analgesic activity relationship, the peculiarities of obtaining, the spatial structure, and biological properties of 4-methyl-2,2-dioxo-1H-2λ6,1-benzothiazine-3-carboxylic acid and some of its derivatives have been studied. Using nuclear magnetic resonance (NMR spectroscopy and X-ray diffraction analysis, it has been proven that varying the reaction conditions using alkaline hydrolysis of methyl 4-methyl-2,2-dioxo-1H-2λ6,1-benzothiazine-3-carboxylate makes it possible to successfully synthesize a monohydrate of the target acid, its sodium salt, or 4-methyl-2,2-dioxo-1H-2λ6,1-benzothiazine. The derivatographic study of the thermal stability of 4-methyl-2,2-dioxo-1H-2λ6,1-benzothiazine-3-carboxylic acid monohydrate has been carried out; based on this study, the optimal conditions completely eliminating the possibility of unwanted decomposition have been proposed for obtaining its anhydrous form. It has been shown that 4-methyl-2,2-dioxo-1H-2λ6,1-benzothiazine is easily formed during the decarboxylation of not only 4-methyl-2,2-dioxo-1H-2λ6,1-benzothiazine-3-carboxylic acid, but also its sodium salt, which is capable of losing СО2 both in rather soft conditions of boiling in an aqueous solution, and in more rigid conditions of dry heating. The NMR spectra of the compounds synthesized are given; their spatial structure is discussed. To study the biological properties of 4-methyl-2,2-dioxo-1H-2λ6,1-benzothiazine-3-carboxylic acid and its sodium salt, the experimental model of inflammation caused by subplantar introduction of the carrageenan solution in one of the hind limbs of white rats was used. The anti-inflammatory activity and analgesic effect were assessed by the degree of edema reduction and the ability to affect the pain response compared to the animals of control groups. According to the results of the tests performed, it has been found that after intraperitoneal injection

  1. Chemo-enzymatic epoxidation of olefins by carboxylic acid esters and hydrogen peroxide

    Energy Technology Data Exchange (ETDEWEB)

    Ruesch gen. Klaas, M.; Warwel, S. [Inst. for Biochemistry and Technology of Lipids, H.P. Kaufmanm-Inst., Federal Centre for Cereal, Potato and Lipid Research, Muenster (Germany)

    1998-12-31

    Ethylen and, recently, butadiene can be epoxidized directly with oxygen and for the epoxidation of propylene, the use of heterogeneous transition metals and organic peroxides (Halcon-Process) is the major player. But, beside from those notable exceptions, all other epoxidations, including large ones like the epoxidation of plant oils as PVC-stabilizers (about 200.000 t/year), are carried out with peroxy acids. Because mcpba is far to expensive for most applications, short chain peracids like peracetic acid are used. Being much less stable than mcpba and thus risky handled in large amounts and high concentrations, these peroxy acids were preferably prepared in-situ. However, conventional in-situ formation of peracids has the serious drawback, that a strong acid is necessary to catalyze peroxy acid formation from the carboxylic acid and hydrogen peroxide. The presence of a strong acid in the reaction mixture often results in decreased selectivity because of the formation of undesired by-products by opening of the oxirane ring. Therefore, we propose a new method for epoxidation based on the in-situ preparation of percarboxylic acids from carboxylic acid esters and hydrogen peroxide catalyzed by a commercial, immobilized lipase. (orig.)

  2. Rapid and selective derivatizatin method for the nitrogen-sensitive detection of carboxylic acids in biological fluids prior to gas chromatographic analysis

    NARCIS (Netherlands)

    Lingeman, H.; Haan, H.B.P.; Hulshoff, A.

    1984-01-01

    A rapid and selective derivatization procedure is described for the pre-column labelling of carboxylic acids with a nitrogen-containing label. The carboxylic acid function is activated with 2-bromo-1-methylpyridinium iodide and the activated carboxylic acid function reacts with a primary or a

  3. ON THE FORMATION OF BENZOIC ACID AND HIGHER-ORDER BENZENE CARBOXYLIC ACIDS IN INTERSTELLAR MODEL ICE GRAINS

    Energy Technology Data Exchange (ETDEWEB)

    McMurtry, Brandon M.; Saito, Sean E. J.; Turner, Andrew M.; Chakravarty, Harish K.; Kaiser, Ralf I. [W. M. Keck Research Laboratory in Astrochemistry, University of Hawaii at Manoa, Honolulu, HI 96822 (United States)

    2016-11-10

    With a binary ice mixture of benzene (C{sub 6}H{sub 6}) and carbon dioxide (CO{sub 2}) at 10 K under contamination-free ultrahigh vacuum conditions, the formation of benzene carboxylic acids in interstellar ice grains was studied. Fourier transform infrared spectroscopy was used to probe for the formation of new species during the chemical processing of the ice mixture and during the following temperature-programmed desorption. Newly formed benzene carboxylic acid species, i.e., benzoic acid, as well as meta - and para -benzene dicarboxylic acid, were assigned using newly emerging bands in the infrared spectrum; a reaction mechanism, along with rate constants, was proposed utilizing the kinetic fitting of the coupled differential equations.

  4. Hepatic Metabolism of Perfluorinated Carboxylic Acids and Polycholorotrifluoroethylene: A Nuclear Magnetic Resonance Investigation in Vivo

    Science.gov (United States)

    1993-01-14

    I14JAN93 Annual Technical Report 15DEC91-1ý+JAN9 4. TITLE AND SUBTITLE 5. FUNDING NUMBERS Hepatic Metabolism of Perfluorinated Carboxylic Acids and G-FS...13. ABSTRACT (Maximum 200 words) This report describes our studies of the effects of perfluorooctanoic acid (PFOA) and perfluorodecanolc acid (PFDA) on...metabolism. 31 p NMR was used to examine the effects of PFDA. PFOA. and clofibrate (C LOF) in both rats and guinea pigs. A unique effect is revealed in

  5. Supramolecular Coordination Assemblies Constructed From Multifunctional Azole-Containing Carboxylic Acids

    Directory of Open Access Journals (Sweden)

    Yuheng Deng

    2010-05-01

    Full Text Available This paper provides a brief review of recent progress in the field of metal coordination polymers assembled from azole-containing carboxylic acids and gives a diagrammatic summary of the diversity of topological structures in the resulting infinite metal-organic coordination networks (MOCNs. Azole-containing carboxylic acids are a favorable kind of multifunctional ligand to construct various metal complexes with isolated complexes and one, two and three dimensional structures, whose isolated complexes are not the focus of this review. An insight into the topology patterns of the infinite coordination polymers is provided. Analyzed topologies are compared with documented topologies and catalogued by the nature of nodes and connectivity pattern. New topologies which are not available from current topology databases are described and demonstrated graphically.

  6. Preparation and reactivity of carboxylic acid-terminated boron-doped diamond electrodes

    International Nuclear Information System (INIS)

    Niedziolka-Joensson, Joanna; Boland, Susan; Leech, Donal; Boukherroub, Rabah; Szunerits, Sabine

    2010-01-01

    The paper reports on the formation of carboxy-terminated boron-doped diamond (BDD) electrodes. The carboxylic acid termination was prepared in a controlled way by reacting photochemically oxidized BDD with succinic anhydride. The resulting interface was readily employed for the linking of an amine-terminated ligand such as an osmium complex bearing an amine terminal group. The interfaces were characterized using X-ray photoelectron spectroscopy (XPS) and cyclic voltammetry (CV). Contact angle measurements were used to follow the changes in surface wetting properties due to surface functionalization. The chemical reactivity of the carboxyl-terminated BDD was investigated by covalent coupling of the acid groups to an amine-terminated osmium complex.

  7. Redshift or adduct stabilization -- a computational study of hydrogen bonding in adducts of protonated carboxylic acids

    DEFF Research Database (Denmark)

    Olesen, Solveig Gaarn; Hammerum, Steen

    2009-01-01

    It is generally expected that the hydrogen bond strength in a D-H-A adduct is predicted by the difference between the proton affinities of D and A, measured by the adduct stabilization, and demonstrated by the IR redshift of the D-H bond stretching vibrational frequency. These criteria do...... not always yield consistent predictions, as illustrated by the hydrogen bonds formed by the E and Z OH groups of protonated carboxylic acids. The delta-PA and the stabilization of a series of hydrogen bonded adducts indicate that the E OH group forms the stronger hydrogen bonds, whereas the bond length...... carboxylic acids are different. The OH bond length and IR redshift afford the better measure of hydrogen bond strength....

  8. Polyoxyethylene alkyl ether carboxylic acids: An overview of a neglected class of surfactants with multiresponsive properties.

    Science.gov (United States)

    Chiappisi, Leonardo

    2017-12-01

    In this work, an overview on aqueous solutions of polyoxyethylene alkyl ether carboxylic acids is given. Unique properties arise from the combination of the nonionic, temperature-responsive polyoxyethylene block with the weakly ionic, pH-responsive carboxylic acid termination in a single surfactant headgroup. Accordingly, this class of surfactant finds broad application across very different sectors. Despite their large use on an industrial and a technical scale, the literature lacks a systematic and detailed characterization of their physico-chemical properties which is provided herein. In addition, a comprehensive overview is given of their self-assembly and interfacial behavior, of their use as colloidal building blocks and for large-scale applications. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Catalytic conversion of carboxylic acids in bio-oil for liquid hydrocarbons production

    International Nuclear Information System (INIS)

    Wang, Shurong; Guo, Zuogang; Cai, Qinjie; Guo, Long

    2012-01-01

    Bio-oil must be upgraded to be suitable for use as a high-grade transport fuel. Crude bio-oil has a high content of carboxylic acids which can cause corrosion, and the high oxygen content of these acids also reduces the oil’s heating value. In this paper, acetic acid and propanoic acid were chosen as the model carboxylic acids in bio-oil. Their behavior in the production of liquid hydrocarbons during a catalytic conversion process was investigated in a micro-fixed bed reactor. The liquid organic phase from this catalytic conversion process mainly consisted of liquid hydrocarbons and phenol derivatives. Under the condition of low Liquid Hourly Space Velocity (LHSV), the liquid organic phase from acetic acid cracking had a selectivity of 22% for liquid hydrocarbons and a selectivity of 65% for phenol derivatives. The composition of the organic products changed considerably with the LHSV increasing to 3 h −1 . The selectivity for liquid hydrocarbons increased up to 52% while that for phenol derivatives decreased to 32%. Propanoic acid performed much better in producing liquid hydrocarbons than acetic acid. Its selectivity for liquid hydrocarbons was as high as 80% at LHSV = 3 h −1 . A mechanism for this catalytic conversion process was proposed according to the analysis of the components in the liquid organic phases. The pathways of the main compounds formation in the liquid organic phases were proposed, and the reason why liquid hydrocarbons were more effectively produced when using propanoic acid rather than acetic acid was also successfully explained. In addition, BET and SEM characterization were used to analyze the catalyst coke deposition. -- Graphical abstract: Display Omitted Highlights: ► High content of carboxylic acids in bio-oil causes its corrosiveness. ► Acetic acid and propanoic acid are two dominant acids in bio-oil. ► Liquid hydrocarbons were produced by cracking of these two dominant acids. ► A mechanism model was proposed to explain

  10. Aminolysis of resin-bound N-nosylaziridine-2-carboxylic acids

    DEFF Research Database (Denmark)

    Olsen, Christian A; Christensen, Caspar; Nielsen, Birgitte

    2006-01-01

    [Structure: see text] Solid-phase synthesis is a rapidly developing area of organic chemistry, of particular importance for medicinal chemistry and chemical biology. Aziridines have previously only rarely been applied in solid-phase synthesis. In the present work, aminolysis of resin-bound, sprin......-loaded N-nitrobenzenesulfonyl-activated aziridine-2-carboxylic acids has been optimized and employed in the synthesis of a number of open-chain and heterocyclic scaffolds, including enantiopure products....

  11. N-Alkylation Using Sodium Triacetoxyborohydride with Carboxylic Acids as Alkyl Sources.

    Science.gov (United States)

    Tamura, Satoru; Sato, Keigo; Kawano, Tomikazu

    2018-01-01

    A versatile N-alkylation was performed using sodium triacetoxyborohydride and carboxylic acid as an alkyl source. The combination of these reagents furnished products different from those given previously by a similar reaction. Moreover, the mild conditions of our method allowed some functional groups to remain through the reaction, whereas they would react and be converted into other moieties in the similar reductive N-alkylation reported previously. Herein, we provide a new procedure for the preparation of various compounds containing nitrogen atoms.

  12. Synthesis of N-acylurea derivatives from carboxylic acids and N,N ...

    Indian Academy of Sciences (India)

    acid 1 (scheme 1) to the basic nitrogen of the carbodi- imide 2, followed by addition of the carboxylate to form the O-acyl isourea 3. It is known10 that in low dielec- tric constant solvents such as CH2Cl2, formation of 3 occurs instantaneously and, in the absence of a nucle- ophile or a base, it can be stable for many hours.

  13. Biotransformation of fluorophenyl pyridine carboxylic acids by the model fungus Cunninghamella elegans.

    Science.gov (United States)

    Palmer-Brown, William; Dunne, Brian; Ortin, Yannick; Fox, Mark A; Sandford, Graham; Murphy, Cormac D

    2017-09-01

    1. Fluorine plays a key role in the design of new drugs and recent FDA approvals included two fluorinated drugs, tedizolid phosphate and vorapaxar, both of which contain the fluorophenyl pyridyl moiety. 2. To investigate the likely phase-I (oxidative) metabolic fate of this group, various fluorinated phenyl pyridine carboxylic acids were incubated with the fungus Cunninghamella elegans, which is an established model of mammalian drug metabolism. 3.  19 F NMR spectroscopy established the degree of biotransformation, which varied depending on the position of fluorine substitution, and gas chromatography-mass spectrometry (GC-MS) identified alcohols and hydroxylated carboxylic acids as metabolites. The hydroxylated metabolites were further structurally characterised by nuclear magnetic resonance spectroscopy (NMR), which demonstrated that hydroxylation occurred on the 4' position; fluorine in that position blocked the hydroxylation. 4. The fluorophenyl pyridine carboxylic acids were not biotransformed by rat liver microsomes and this was a consequence of inhibitory action, and thus, the fungal model was crucial in obtaining metabolites to establish the mechanism of catabolism.

  14. In Vitro Reactivity of Carboxylic Acid-CoA Thioesters with Glutathione

    DEFF Research Database (Denmark)

    Sidenius, Ulrik; Skonberg, Christian; Olsen, Jørgen

    2004-01-01

    was to investigate whether a correlation could be found between the structure of acyl-CoA thioesters and their reactivities toward the tripeptide, glutathione (ç- Glu-Cys-Gly).  The  acyl-CoA  thioesters  of  eight  carboxylic  acids  (ibuprofen,  clofibric  acid, indomethacin,  fenbufen,  tolmetin,  salicylic  acid......The chemical reactivity of acyl-CoA thioesters toward nucleophiles has been demonstrated in several recent studies. Thus, intracellularly formed acyl-CoAs of xenobiotic carboxylic acids may react covalently with endogenous proteins and potentially lead to adverse effects. The purpose of this study......,  2-phenoxypropionic  acid,  and  (4-chloro-2-methyl-phenoxy)acetic  acid  (MCPA))  were  synthesized,  and  each  acyl-CoA  (0.5  mM)  was incubated with glutathione (5.0 mM) in 0.1 M potassium phosphate (pH 7.4, 37 °C). All of the acyl-CoAs reacted with glutathione to form the respective acyl...

  15. Determination of tetrahydrophtalimide and 2-thiothiazolidine-4-carboxylic acid, urinary metabolites of the fungicide captan, in rats and humans

    NARCIS (Netherlands)

    van Welie, R.T.H.; van Duyn, P; Lamme, E K; Jäger, P; van Baar, B L; Vermeulen, N P

    1991-01-01

    Capillary gas chromatographic (GC) methods using sulphur and mass selective detection for the qualitative and quantitative determination of tetrahydrophtalimide (THPI) and 2-thiothiazolidine-4-carboxylic acid (TTCA), urinary metabolites of the fungicide captan in rat and humans, were developed.

  16. Determination of the Cyanide Metabolite 2-Aminothiazoline-4-Carboxylic Acid in Urine and Plasma by Gas Chromatography-Mass Spectrometry

    National Research Council Canada - National Science Library

    Logue, Brian A; Kirschten, Nicholas P; Petrikovics, Ilona; Moser, Matthew A; Rockwood, Gary A; Baskin, Steven I

    2005-01-01

    The cyanide metabolite 2-aminothiazoline.4-carboxylic acid (ATCA) is a promising biomarker for cyanide exposure because of its stability and the limitations of direct determination of cyanide and more abundant cyanide metabolites...

  17. Aldehydes, ketones, and carboxylic acids formed radiolytically in aqueous solutions of cyanides and simple nitriles

    International Nuclear Information System (INIS)

    Negron-Mendoza, A.; Draganic, Z.D.; Navarro-Gonzalez, R.; Graganic, I.G.

    1983-01-01

    A systematic search for aldehydes, ketones, and carboxylic acids was carried out in aqueous solutions of HCN, NH 4 CN, CH 3 CN, and C 2 H 4 CN, that had received multikilogray doses of 60 Co γ radiation. About 30 radiolytic products were identified, among them a large variety of dicarboxylic and tricarboxylic acids. Some of them might be of significant interest in molecular evolution studies of prebiotic processes. They originate in the free-radical-initiated chemical reactions where the additional oligomerization processes are particularly important. Most of the radiolytic products appear in both cyanides and nitriles and point to the importance of reactions involving the carbon-nitrogen triple bond

  18. Mechanism of catalytic action of oxide systems in reactions of aldehyde oxidation to carboxylic acids

    International Nuclear Information System (INIS)

    Andrushkevich, T.V.

    1997-01-01

    Mechanism of selective action of oxide catalysts (on the base of V 2 O 4 , MoO 3 ) of aldehyde oxidation to acids is considered, reaction acrolein oxidation to acrylic acid is taken as an example. Multistage mechanism of the process is established; it involves consequent transformation of coordination-bonded aldehyde into carbonyl-bonded aldehyde and symmetric carboxylate. Principles of active surface construction are formulated, they take into account the activity of stabilization center of concrete intermediate compound and bond energy of oxygen with surface. (author)

  19. A relativistic density functional study of uranyl hydrolysis and complexation by carboxylic acids in aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Ray, Rupashree Shyama

    2009-02-10

    In this work, the complexation of uranium in its most stable oxidation state VI in aqueous solution was studied computationally, within the framework of density functional (DF) theory. The thesis is divided into the following parts: Chapter 2 briefly summarizes the relevant general aspects of actinide chemistry and then focuses on actinide environmental chemistry. Experimental results on hydrolysis, actinide complexation by carboxylic acids, and humic substances are presented to establish a background for the subsequent discussion. Chapter 3 describes the computational method used in this work and the relevant features of the parallel quantum chemistry code PARAGAUSS employed. First, the most relevant basics of the applied density functional approach are presented focusing on relativistic effects. Then, the treatment of solvent effects, essential for an adequate modeling of actinide species in aqueous solution, will be introduced. At the end of this chapter, computational parameters and procedures will be summarized. Chapter 4 presents the computational results including a comparison to available experimental data. In the beginning, the mononuclear hydrolysis product of UO{sub 2}{sup 2+}, [UO{sub 2}OH]{sup +}, will be discussed. The second part deals with actinide complexation by carboxylate ligands. First of all the coordination number for uranylacetate will be discussed with respect to implications for the complexation of actinides by humic substances followed by the uranyl complexation of aromatic carboxylic acids in comparison to earlier results for aliphatic ones. In the end, the ternary uranyl-hydroxo-acetate are discussed, as models of uranyl humate complexation at ambient condition.

  20. Carboxylic acid functionalization of halloysite nanotubes for sustained release of diphenhydramine hydrochloride

    Energy Technology Data Exchange (ETDEWEB)

    Zargarian, S. Sh.; Haddadi-Asl, V., E-mail: haddadi@aut.ac.ir; Hematpour, H. [Amirkabir University of Technology, Department of Polymer Engineering and Color Technology (Iran, Islamic Republic of)

    2015-05-15

    Halloysite nanotubes (HNT) (cylindrical shape with external diameter and length in the range of 30–80 nm and 0.2–1 µm, respectively) were functionalized with 3-aminopropyltriethoxysilane (APTES) from hydroxyl groups by a coupling reaction. Subsequently, maleic anhydride was attached to the APTES moieties to yield carboxylic acid-functionalized HNT. Loading and subsequent release of a model drug molecule diphenhydramine hydrochloride (DPH) on modified and unmodified nanotubes were investigated. Morphology of HNT was studied by electron microscopy. Successful attachment of APTES and carboxylic acid groups to halloysite and drug loading were evaluated by Fourier transform infrared spectroscopy. The amount of surface modification and drug adsorption capacity were calculated via thermogravimetric analysis. The ordered crystal structure of loaded drug was evaluated by X-ray diffraction. UV–Visible spectrophotometer was used to study drug release from modified and unmodified samples. Carboxylated halloysite exhibits higher loading capacity and prolonged release of DPH as compared to that of the natural halloysite.

  1. Carboxylic acid functionalization of halloysite nanotubes for sustained release of diphenhydramine hydrochloride

    International Nuclear Information System (INIS)

    Zargarian, S. Sh.; Haddadi-Asl, V.; Hematpour, H.

    2015-01-01

    Halloysite nanotubes (HNT) (cylindrical shape with external diameter and length in the range of 30–80 nm and 0.2–1 µm, respectively) were functionalized with 3-aminopropyltriethoxysilane (APTES) from hydroxyl groups by a coupling reaction. Subsequently, maleic anhydride was attached to the APTES moieties to yield carboxylic acid-functionalized HNT. Loading and subsequent release of a model drug molecule diphenhydramine hydrochloride (DPH) on modified and unmodified nanotubes were investigated. Morphology of HNT was studied by electron microscopy. Successful attachment of APTES and carboxylic acid groups to halloysite and drug loading were evaluated by Fourier transform infrared spectroscopy. The amount of surface modification and drug adsorption capacity were calculated via thermogravimetric analysis. The ordered crystal structure of loaded drug was evaluated by X-ray diffraction. UV–Visible spectrophotometer was used to study drug release from modified and unmodified samples. Carboxylated halloysite exhibits higher loading capacity and prolonged release of DPH as compared to that of the natural halloysite

  2. A relativistic density functional study of uranyl hydrolysis and complexation by carboxylic acids in aqueous solution

    International Nuclear Information System (INIS)

    Ray, Rupashree Shyama

    2009-01-01

    In this work, the complexation of uranium in its most stable oxidation state VI in aqueous solution was studied computationally, within the framework of density functional (DF) theory. The thesis is divided into the following parts: Chapter 2 briefly summarizes the relevant general aspects of actinide chemistry and then focuses on actinide environmental chemistry. Experimental results on hydrolysis, actinide complexation by carboxylic acids, and humic substances are presented to establish a background for the subsequent discussion. Chapter 3 describes the computational method used in this work and the relevant features of the parallel quantum chemistry code PARAGAUSS employed. First, the most relevant basics of the applied density functional approach are presented focusing on relativistic effects. Then, the treatment of solvent effects, essential for an adequate modeling of actinide species in aqueous solution, will be introduced. At the end of this chapter, computational parameters and procedures will be summarized. Chapter 4 presents the computational results including a comparison to available experimental data. In the beginning, the mononuclear hydrolysis product of UO_2"2"+, [UO_2OH]"+, will be discussed. The second part deals with actinide complexation by carboxylate ligands. First of all the coordination number for uranylacetate will be discussed with respect to implications for the complexation of actinides by humic substances followed by the uranyl complexation of aromatic carboxylic acids in comparison to earlier results for aliphatic ones. In the end, the ternary uranyl-hydroxo-acetate are discussed, as models of uranyl humate complexation at ambient condition.

  3. Copper coordination polymers constructed from thiazole-5-carboxylic acid: Synthesis, crystal structures, and structural transformation

    Energy Technology Data Exchange (ETDEWEB)

    Meundaeng, Natthaya; Rujiwatra, Apinpus [Department of Chemistry, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Prior, Timothy J., E-mail: t.prior@hull.ac.uk [Chemistry, University of Hull, Kingston upon Hull HU6 7RX (United Kingdom)

    2017-01-15

    We have successfully prepared crystals of thiazole-5-carboxylic acid (5-Htza) (L) and three new thiazole-5-carboxylate-based Cu{sup 2+} coordination polymers with different dimensionality, namely, 1D [Cu{sub 2}(5-tza){sub 2}(1,10-phenanthroline){sub 2}(NO{sub 3}){sub 2}] (1), 2D [Cu(5-tza){sub 2}(MeOH){sub 2}] (2), and 3D [Cu(5-tza){sub 2}]·H{sub 2}O (3). These have been characterized by single crystal X-ray diffraction and thermogravimetry. Interestingly, the 2D network structure of 2 can directly transform into the 3D framework of 3 upon removal of methanol molecules at room temperature. 2 can also undergo structural transformation to produce the same 2D network present in the known [Cu(5-tza){sub 2}]·1.5H{sub 2}O upon heat treatment for 2 h. This 2D network can adsorb water and convert to 3 upon exposure to air. - Highlights: • Rare examples of coordination polymers of thiazole-5-carboxylic acid were prepared. • Non-covalent interactions play a key role on the assembly of the complexes in solid state. • Structural transformation of a 2D framework to a 3D upon removal of methanol is observed.

  4. 40 CFR 721.3620 - Fatty acid amine condensate, polycarboxylic acid salts.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Fatty acid amine condensate... Specific Chemical Substances § 721.3620 Fatty acid amine condensate, polycarboxylic acid salts. (a... a fatty acid amine condensate, polycarboxylic acid salts. (PMN P-92-445) is subject to reporting...

  5. Recovery of carboxylic acids at pH greater than pKa

    Energy Technology Data Exchange (ETDEWEB)

    Tung, Lisa A. [Univ. of California, Berkeley, CA (United States)

    1993-08-01

    Economics of producing carboxylic acids by fermentation is often dominated, not by the fermentation cost, but by the cost of recovering and purifying the acids from dilute aqueous solutions. Experiments were performed to measure uptakes of lactic and succinic acids as functions of pH by basic polymeric sorbents; sorbent regeneration was also tested. Performance at pH > pKa and regenerability depend on sorbent basicity; apparent pKa and monomer pK{sub a} can be used to predict sorbent performance. Two basic amine extractants, Alamine 336 and Amberlite LA-2, in were also studied; they are able to sustain capacity to higher pH in diluents that stabilize the acid-amine complex through H bonding. Secondary amines perform better than tert-amines in diluents that solvate the additional proton. Competitive sulfate and phosphate, an interference in fermentation, are taken up by sorbents more strongly than by extractants. The third step in the proposed fermentation process, the cracking of the trimethylammonium (TMA) carboxylate, was also examined. Because lactic acid is more soluble and tends to self-esterify, simple thermal cracking does not remove all TMA; a more promising approach is to esterify the TMA lactate by reaction with an alcohol.

  6. Effect of carboxylic acids as compatibilizer agent on mechanical properties of thermoplastic starch and polypropylene blends.

    Science.gov (United States)

    Martins, Andréa Bercini; Santana, Ruth Marlene Campomanes

    2016-01-01

    In this work, polypropylene/thermoplastic starch (PP/TPS) blends were prepared as an alternative material to use in disposable packaging, reducing the negative polymeric environmental impact. Unfortunately, this material displays morphological characteristics typical of immiscible polymer blends and a compatibilizer agent is needed. Three different carboxyl acids: myristic (C14), palmitic (C16) and stearic acids (C18) were used as natural compatibilizer agent (NCA). The effects of NCA on the mechanical, physical, thermal and morphological properties of PP/TPS blends were investigated and compared against PP/TPS with and without PP-grafted maleic anhydride (PPgMA). When compared to PP/TPS, blends with C18, PPgMA and C14 presented an improvement of 25, 22 and 17% in tensile strength at break and of 180, 194 and 259% in elongation at break, respectively. The highest increase, 54%, in the impact strength was achieved with C14 incorporation. Improvements could be seen, through scanning electron microscopy (SEM) images, in the compatibility between the immiscible components by acids incorporation. These results showed that carboxylic acids, specifically C14, could be used as compatibilizer agent and could substitute PPgMA. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. Kinetic analysis of the reactivity of aliphatic cyclic alcohols and carboxylic acids in the T-for-H exchange reaction

    International Nuclear Information System (INIS)

    Tamura, Kiyoshi; Imaizumi, Hiroshi; Kano, Naoki

    2007-01-01

    In order to quantitatively evaluate the influence of tritium ( 3 He or T) on various functional groups in environment, the hydrogen isotope exchange reaction (T-for-H exchange reaction) between tritium-labeled poly-(vinyl alcohol) and each aliphatic cyclic alcohol (or carboxylic acid) has been dynamically observed in the range of 50 to 90degC. Consequently, the activities of the aliphatic cyclic alcohol and carboxylic acid increased with increasing reaction time. Applying in A''-McKay plot method to the observed data, the rate constants (k) for these materials were obtained. Using the k, the relation between the number of carbon atoms in the ring in each alcohol and the reactivity of the alcohol was quantitatively compared. Then, to clarify the effect of relative atomic charge of O atom (connected with the H atom in the hydroxy (or carboxy) group in the material) on the reactivity of the material, the MOPAC method was used. From both the above-mentioned and the obtained previously, the following nine items were found as to aliphatic cyclic alcohols (and carboxylic acids) in the T-for-H exchange reaction. (1) The reactivity of aliphatic cyclic alcohols (and carboxylic acids) depends on the temperature. (2) The reactivity of the cyclic materials decreases with increasing number of carbon atoms in the ring. (3) The reactivity of the aliphatic cyclic carboxylic acid seems to be smaller than that of aliphatic cyclic alcohol, and be larger than that of aliphatic cyclic amine. (4) For aliphatic cyclic alcohols, correlation exists between k and relative atomic charges of O atom obtained by the MOPAC method, but the tendency for aliphatic cyclic carboxylic acid is not clear. (5) As to having the same number of carbon atoms in each ring, the reactivity of the aliphatic cyclic carboxylic acid including the side chain is smaller than of the aliphatic cyclic carboxylic acid including no side chain. (6) The reactivity of aliphatic cyclic carboxylic acid is larger than that of

  8. Crystalline insoluble acid salts of tetravalent metals

    International Nuclear Information System (INIS)

    Alberti, G.; Bernasconi, M.G.; Casciola, M.; Costantino, U.

    1980-01-01

    Several titration curves of crystalline acid salts of tetravalent metals show an evident decrease in the pH of the supernatant solution with an increasing addition of metal hydroxide. This phenomenon, very unusual for common organic ion-exchangers, seems to be quite general for inorganic ion-exchangers with layered structure of α-type. In order to throw light on this phenomenon, a detailed investigation was carried out on the titration curves of α-Zr(HPO 4 ) 2 .H 2 O with various metal hydroxides, particularly KOH. To obtain the presence of a distinct minimum in the titration curve, three conditions seem to be necessary: (1) high activation energy for H + /Msup(Z+) exchange (which, in turn, depends on the relative size of Msup(Z+) and size of the windows connecting the cavities), (2) formation of solid solution having high M-content and (3) formation of a phase, with a large inter-layer distance, in the external parts of the crystals. This last point is particularly important since the enlargement of the external part of the crystals lowers the activation energy for the exchange of large cations. Thus, once started, the exchange can take place at lower pH' values. (author)

  9. Two dialkylammonium salts of 2-amino-4-nitrobenzoic acid: crystal structures and Hirshfeld surface analysis

    Directory of Open Access Journals (Sweden)

    James L. Wardell

    2016-12-01

    Full Text Available The crystal structures of two ammonium salts of 2-amino-4-nitrobenzoic acid are described, namely dimethylazanium 2-amino-4-nitrobenzoate, C2H8N+·C7H5N2O4−, (I, and dibutylazanium 2-amino-4-nitrobenzoate, C8H20N+·C7H5N2O4−, (II. The asymmetric unit of (I comprises a single cation and a single anion. In the anion, small twists are noted for the carboxylate and nitro groups from the ring to which they are connected, as indicated by the dihedral angles of 11.45 (13 and 3.71 (15°, respectively; the dihedral angle between the substituents is 7.9 (2°. The asymmetric unit of (II comprises two independent pairs of cations and anions. In the cations, different conformations are noted in the side chains in that three chains have an all-trans [(+-antiperiplanar] conformation, while one has a distinctive kink resulting in a (+-synclinal conformation. The anions, again, exhibit twists with the dihedral angles between the carboxylate and nitro groups and the ring being 12.73 (6 and 4.30 (10°, respectively, for the first anion and 8.1 (4 and 12.6 (3°, respectively, for the second. The difference between anions in (I and (II is that in the anions of (II, the terminal groups are conrotatory, forming dihedral angles of 17.02 (8 and 19.0 (5°, respectively. In each independent anion of (I and (II, an intramolecular amino-N—H...O(carboxylate hydrogen bond is formed. In the crystal of (I, anions are linked into a jagged supramolecular chain by charge-assisted amine-N—H...O(carboxylate hydrogen bonds and these are connected into layers via charge-assisted ammonium-N—H...O(carboxylate hydrogen bonds. The resulting layers stack along the a axis, being connected by nitro-N—O...π(arene and methyl-C—H...O(nitro interactions. In the crystal of (II, the anions are connected into four-ion aggregates by charge-assisted amino-N—H...O(carboxylate hydrogen bonding. The formation of ammonium-N—H...O(carboxylate hydrogen bonds, involving

  10. Towards modelling the vibrational signatures of functionalized surfaces: carboxylic acids on H-Si(111) surfaces

    Science.gov (United States)

    Giresse Tetsassi Feugmo, Conrard; Champagne, Benoît; Caudano, Yves; Cecchet, Francesca; Chabal, Yves J.; Liégeois, Vincent

    2012-03-01

    In this work, we investigate the adsorption process of two carboxylic acids (stearic and undecylenic) on a H-Si(111) surface via the calculation of structural and energy changes as well as the simulation of their IR and Raman spectra. The two molecules adsorb differently at the surface since the stearic acid simply physisorbs while the undecylenic acid undergoes a chemical reaction with the hydrogen atoms of the surface. This difference is observed in the change of geometry during the adsorption. Indeed, the chemisorption of the undecylenic acid has a bigger impact on the structure than the physisorption of the stearic acid. Consistently, the former is also characterized by a larger value of adsorption energy and a smaller value of the tilting angle with respect to the normal plane. For both the IR and Raman signatures, the spectra of both molecules adsorbed at the surface are in a first approximation the superposition of the spectra of the Si cluster and of the carboxylic acid considered individually. The main deviation from this simple observation is the peak of the stretching Si-H (ν(Si-H)) mode, which is split into two peaks upon adsorption. As expected, the splitting is bigger for the chemisorption than the physisorption. The modes corresponding to atomic displacements close to the adsorption site display a frequency upshift by a dozen wavenumbers. One can also see the disappearance of the peaks associated with the C=C double bond when the undecylenic acid chemisorbs at the surface. The Raman and IR spectra are complementary and one can observe here that the most active Raman modes are generally IR inactive. Two exceptions to this are the two ν(Si-H) modes which are active in both spectroscopies. Finally, we compare our simulated spectra with some experimental measurements and we find an overall good agreement.

  11. Towards modelling the vibrational signatures of functionalized surfaces: carboxylic acids on H-Si(111) surfaces

    International Nuclear Information System (INIS)

    Tetsassi Feugmo, Conrard Giresse; Champagne, Benoît; Liégeois, Vincent; Caudano, Yves; Cecchet, Francesca; Chabal, Yves J

    2012-01-01

    In this work, we investigate the adsorption process of two carboxylic acids (stearic and undecylenic) on a H-Si(111) surface via the calculation of structural and energy changes as well as the simulation of their IR and Raman spectra. The two molecules adsorb differently at the surface since the stearic acid simply physisorbs while the undecylenic acid undergoes a chemical reaction with the hydrogen atoms of the surface. This difference is observed in the change of geometry during the adsorption. Indeed, the chemisorption of the undecylenic acid has a bigger impact on the structure than the physisorption of the stearic acid. Consistently, the former is also characterized by a larger value of adsorption energy and a smaller value of the tilting angle with respect to the normal plane. For both the IR and Raman signatures, the spectra of both molecules adsorbed at the surface are in a first approximation the superposition of the spectra of the Si cluster and of the carboxylic acid considered individually. The main deviation from this simple observation is the peak of the stretching Si-H (ν(Si-H)) mode, which is split into two peaks upon adsorption. As expected, the splitting is bigger for the chemisorption than the physisorption. The modes corresponding to atomic displacements close to the adsorption site display a frequency upshift by a dozen wavenumbers. One can also see the disappearance of the peaks associated with the C=C double bond when the undecylenic acid chemisorbs at the surface. The Raman and IR spectra are complementary and one can observe here that the most active Raman modes are generally IR inactive. Two exceptions to this are the two ν(Si-H) modes which are active in both spectroscopies. Finally, we compare our simulated spectra with some experimental measurements and we find an overall good agreement. (paper)

  12. Biological roles and therapeutic potential of hydroxy-carboxylic acid receptors

    Directory of Open Access Journals (Sweden)

    Kashan eAhmed

    2011-10-01

    Full Text Available In the recent past, deorphanization studies have described intermediates of energy metabolism to activate G protein-coupled receptors (GPCRs and to thereby regulate metabolic functions. GPR81, GPR109A and GPR109B, formerly known as the nicotinic acid receptor family, are encoded by clustered genes and share a high degree of sequence homology. Recently, hydroxy-carboxylic acids were identified as endogenous ligands of GPR81, GPR109A and GPR109B, and therefore these receptors have been placed into a novel receptor family of hydroxy-carboxylic acid (HCA receptors. The HCA1 receptor (GPR81 is activated by the glycolytic metabolite 2-hydroxy-propionic acid (lactate, the HCA2 receptor is activated by the ketone body 3-hydroxy-butyric acid and the HCA3 receptor (GPR109B is a receptor for the β-oxidation intermediate 3-hydroxy-octanoic acid. While HCA1 and HCA2 receptors are present in most mammalian species, the HCA3 receptor is exclusively found in humans and higher primates. HCA receptors are expressed in adipose tissue and mediate anti-lipolytic effects in adipocytes through Gi-type G-protein-dependent inhibition of adenylyl cyclase. HCA2 and HCA3 inhibit lipolysis during conditions of increased β-oxidation such as prolonged fasting, whereas HCA1 mediates the anti-lipolytic effects of insulin in the fed state. As HCA2 is a receptor for the established anti-dyslipidemic drug nicotinic acid, HCA1 and HCA3 also represent promising drug targets and several synthetic ligands for HCA receptors have been developed. In this article, we will summarize the deorphanization and pharmacological characterization of HCA receptors. Moreover, we will discuss recent progress in elucidating the physiological and pathophysiological role to further evaluate the therapeutic potential of the HCA receptor family for the treatment of metabolic disease.

  13. Boron-Catalyzed N-Alkylation of Amines using Carboxylic Acids.

    Science.gov (United States)

    Fu, Ming-Chen; Shang, Rui; Cheng, Wan-Min; Fu, Yao

    2015-07-27

    A boron-based catalyst was found to catalyze the straightforward alkylation of amines with readily available carboxylic acids in the presence of silane as the reducing agent. Various types of primary and secondary amines can be smoothly alkylated with good selectivity and good functional-group compatibility. This metal-free amine alkylation was successfully applied to the synthesis of three commercial medicinal compounds, Butenafine, Cinacalcet. and Piribedil, in a one-pot manner without using any metal catalysts. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Omega-3 carboxylic acids monotherapy and combination with statins in the management of dyslipidemia

    Directory of Open Access Journals (Sweden)

    Benes LB

    2016-12-01

    Full Text Available Lane B Benes1, Nikhil S Bassi2, Michael H Davidson1 1Department of Medicine, Section of Cardiology, 2Department of Medicine, University of Chicago, Chicago, IL, USA Abstract: The 2013 American College of Cardiology/American Heart Association guidelines on cholesterol management placed greater emphasis on statin therapy given the well-established benefits in primary and secondary prevention of cardiovascular disease. Residual risk may remain after statin initiation, in part because of triglyceride-rich lipoprotein cholesterol. Several large trials have failed to show benefit with non-statin cholesterol-lowering medications in the reduction of cardiovascular events. Yet, subgroup analyses showed a benefit in those with hypertriglyceridemia and lower high-density lipoprotein cholesterol level, a high-risk pattern of dyslipidemia. This review discusses the benefits of omega-3 carboxylic acids, a recently approved formulation of omega-3 fatty acid with enhanced bioavailability, in the treatment of dyslipidemia both as monotherapy and combination therapy with a statin. Keywords: omega-3 carboxylic acids, non-HDL-C, hypertriglyceridemia, residual risk, statin

  15. Kinetic studies on the carboxylation of 6-amino-penicillanic acid to 8-hydroxy-penillic acid

    DEFF Research Database (Denmark)

    Henriksen, Claus Maxel; Holm, SS; Schipper, D.

    1997-01-01

    The carboxylation in aqueous solution of 6-amino-penicillanic acid (6-APA) to 8-hydroxy-penillic acid (8-HPA) was studied at 25 degrees C and pH 6.5. During sparging with either a citrate buffer or a chemically defined cultivation medium containing 6-APA with mixtures of carbon dioxide and air (2.......7-41% (v/v) CO2), the kinetics for conversion of 6-APA was followed by HPLC. In the citrate buffer 6-APA was converted by two competitive reactions each following first order kinetics with respect to the concentration of 6-APA: 1. carboxylation into 8-HPA; and 2. slow conversion into an unknown compound....... Formation of the unknown compound was not observed in the cultivation medium. The carboxylation of 6-APA was also found to be first order with respect to the concentration of dissolved carbon dioxide. The rate constant for formation of 8-HPA did not differ significantly in the cultivation medium compared...

  16. Investigations of the reactivity of pyridine carboxylic acids with diazodiphenylmethane in protic and aprotic solvents.

    Directory of Open Access Journals (Sweden)

    ALEKSANDAR D. MARINKOVIC

    2005-04-01

    Full Text Available Rate constants for the reaction of diazodiphenylmethane with isomeric pyridine carboxylic acids were determined in chosen protic and aprotic solvents at 30 °C, using the well known UV spectrophotometric method. The values of the rate constants of the investigated acids in protic solvents were higher than those in aprotic solvents. The second order rate constants were correlated with solvent parameters using the Kamlet-Taft solvatochromic equation in the form: log k = log k0 + sp* + aa + bb . The correlation of the obtained kinetic data were performed by means of multiple linear regression analysis taking appropriate solvent parameters. The signs of the equation coefficients were in agreement with the postulated reaction mechanism. The mode of the influence of the solvent on the reaction rate in all the investigated acids are discussed on the basis of the correlation results.

  17. Enriched surface acidity for surfactant-free suspensions of carboxylated carbon nanotubes purified by centrifugation

    Directory of Open Access Journals (Sweden)

    Elizabeth I. Braun

    2016-06-01

    Full Text Available It is well known that surfactant-suspended carbon nanotube (CNT samples can be purified by centrifugation to decrease agglomerates and increase individually-dispersed CNTs. However, centrifugation is not always part of protocols to prepare CNT samples used in biomedical applications. Herein, using carboxylated multi-walled CNTs (cMWCNTs suspended in water without a surfactant, we developed a Boehm titrimetric method for the analysis of centrifuged cMWCNT suspensions and used it to show that the surface acidity of oxidized carbon materials in aqueous cMWCNT suspensions was enriched by ∼40% by a single low-speed centrifugation step. This significant difference in surface acidity between un-centrifuged and centrifuged cMWCNT suspensions has not been previously appreciated and is important because the degree of surface acidity is known to affect the interactions of cMWCNTs with biological systems.

  18. Immobilization of dendrimers on Si-C linked carboxylic acid-terminated monolayers on silicon(111)

    International Nuclear Information System (INIS)

    Boecking, Till; Wong, Elicia L.S.; James, Michael; Watson, Jolanta A.; Brown, Christopher L.; Chilcott, Terry C.; Barrow, Kevin D.; Coster, Hans G.L.

    2006-01-01

    Poly(amidoamine) dendrimers were attached to activated undecanoic acid monolayers, covalently linked to smooth silicon surfaces via Si-C bonds. The resulting ultra-thin dendrimer films were characterized by X-ray photoelectron spectroscopy (XPS), X-ray reflectometry (XR) and atomic force microscopy (AFM). XPS results suggested amide bond formation between the dendrimer and the surface carboxylic acid groups. XR yielded thicknesses of 10 A for the alkyl region of the undecanoic acid monolayer and 12 A for the dendrimer layer, considerably smaller than the diameter of these spherical macromolecules in solution. This was consistent with AFM images showing collapsed dendrimers on the surface. It was concluded that the deformation arose from a large number of amine groups on the surface of each dendrimer reacting efficiently with the activated surface, whereby the dendrimers can deform to fill voids while spreading over the activated surface to form a homogeneous macromolecular layer

  19. Exogenous ascorbic acid increases resistance to salt of Silybum ...

    African Journals Online (AJOL)

    However, irrigation with salt water enhanced carotenoids and antioxidant enzyme activities. The detrimental effects of salt water were ameliorated by application of 100 ppm ascorbic acid (vitamin C). The inductive role of vitamin was associated with the improvement of seed germination, growth, plant water status, ...

  20. Cryoprotection properties of salts of organic acids: a case study for a tetragonal crystal of HEW lysozyme.

    Science.gov (United States)

    Bujacz, Grzegorz; Wrzesniewska, Blanka; Bujacz, Anna

    2010-07-01

    Currently, the great majority of the data that are used for solving macromolecular structures by X-ray crystallography are collected at cryogenic temperatures. Selection of a suitable cryoprotectant, which ensures crystal stability at low temperatures, is critical for the success of a particular diffraction experiment. The effectiveness of salts of organic acids as potential cryoprotective agents is presented in the following work. Sodium formate, acetate, malonate and citrate were tested, as were sodium potassium tartrate and acetate in the form of potassium and ammonium salts. For each salt investigated, the minimal concentration that was required for successful cryoprotection was determined over the pH range 4.5-9.5. The cryoprotective ability of these organic salts depends upon the number of carboxylic groups; the lowest concentration required for cryoprotection was observed at neutral pH. Case-study experiments conducted using the tetragonal form of hen egg-white lysozyme (HEWL) confirmed that salts of organic acids can successfully act as cryoprotective agents of protein crystals grown from high concentrations of inorganic salts. When crystals are grown from solutions containing a sufficient concentration of organic acid salts no additional cryoprotection is needed as the crystals can safely be frozen directly from the crystallizing buffers.

  1. On the Existence of Hydrogen Salts of Monoprotic Acids

    Science.gov (United States)

    Stojanovska, Marina I.; Petrusevski, Vladimir M.; Soptrajanov, Bojan T.

    2012-01-01

    The notion that acid salts exist only for diprotic and polyprotic acids is found in many high school and university textbooks, although the "only" condition is not always stated explicitly. A fairly simple experiment shows that there is a pronounced exothermic effect when pure acetic acid is added to potassium acetate. Experiments with similar…

  2. Inert Reassessment Document for Gluconic Acid and Sodium Salt

    Science.gov (United States)

    Gluconic acid and D-gluconic acid are classified as List 3 inert ingredients, sodium gluconate is classified as a List 4B inert ingredient, and D-gluconic acid, sodium salt has not been categorized as to inert ingredient list classification status.

  3. Density, viscosity, and N2O solubility of aqueous amino acid salt and amine amino acid salt solutions

    International Nuclear Information System (INIS)

    Aronu, Ugochukwu E.; Hartono, Ardi; Svendsen, Hallvard F.

    2012-01-01

    Highlights: ► Density of amino acid salt and amine amino acid salt. ► Viscosity of amino acid salt and amine amino acid salt. ► Henry’s law constant/N 2 O solubility of amino acid salt and amine amino acid salt. ► Schumpe model. Correlations for density, viscosity, and N 2 O solubility. - Abstract: Physicochemical properties of aqueous amino acid salt (AAS), potassium salt of sarcosine (KSAR) and aqueous amine amino acid salt (AAAS), 3-(methylamino)propylamine/sarcosine (SARMAPA) have been studied. Densities of KSAR were measured for sarcosine mole fraction 0.02 to 0.25 for temperature range 298.15 K to 353.15 K, the viscosities were measured for 0.02 to 0.10 mole fraction sarcosine (293.15 K to 343.15 K) while the N 2 O solubilities were measured from 0.02 to 0.10 mole fraction sarcosine solutions (298.15 K to 363.15 K). Densities of SARMAPA were measured for sarcosine mole fraction 0.02 to 0.23 for temperature range (298.15 K to 353.15 K), viscosities were measured for 0.02 to 0.16 mole fraction sarcosine (293.15 K to 343.15 K) while the N 2 O solubilities were measured from 0.02 to 0.16 mole fraction sarcosine solutions (298.15 K to 343.15 K). Experimental results were correlated well with empirical correlations and N 2 O solubility results for KSAR were predicted adequately by a Schumpe model. The solubilities of N 2 O in AAS and AAAS are significantly lower than values for amines. The solubilities vary as: amine > AAAS > AAS.

  4. Structural evidence for solvent-stabilisation by aspartic acid as a mechanism for halophilic protein stability in high salt concentrations.

    Science.gov (United States)

    Lenton, Samuel; Walsh, Danielle L; Rhys, Natasha H; Soper, Alan K; Dougan, Lorna

    2016-07-21

    Halophilic organisms have adapted to survive in high salt environments, where mesophilic organisms would perish. One of the biggest challenges faced by halophilic proteins is the ability to maintain both the structure and function at molar concentrations of salt. A distinct adaptation of halophilic proteins, compared to mesophilic homologues, is the abundance of aspartic acid on the protein surface. Mutagenesis and crystallographic studies of halophilic proteins suggest an important role for solvent interactions with the surface aspartic acid residues. This interaction, between the regions of the acidic protein surface and the solvent, is thought to maintain a hydration layer around the protein at molar salt concentrations thereby allowing halophilic proteins to retain their functional state. Here we present neutron diffraction data of the monomeric zwitterionic form of aspartic acid solutions at physiological pH in 0.25 M and 2.5 M concentration of potassium chloride, to mimic mesophilic and halophilic-like environmental conditions. We have used isotopic substitution in combination with empirical potential structure refinement to extract atomic-scale information from the data. Our study provides structural insights that support the hypothesis that carboxyl groups on acidic residues bind water more tightly under high salt conditions, in support of the residue-ion interaction model of halophilic protein stabilisation. Furthermore our data show that in the presence of high salt the self-association between the zwitterionic form of aspartic acid molecules is reduced, suggesting a possible mechanism through which protein aggregation is prevented.

  5. Cyclohex-1-ene carboxylic acids: synthesis and biological evaluation of novel inhibitors of human 5 alpha reductase.

    Science.gov (United States)

    Baston, Eckhard; Salem, Ola I A; Hartmann, Rolf W

    2003-03-01

    In search of novel nonsteroidal mimics of steroidal inhibitors of 5 alpha reductase, 4-(2-phenylethyl)cyclohex-1-ene carboxylic acids 1-5 were synthesized with different substituents in para position of the phenyl ring (1: N, N-diisopropylcarbamoyl, 2: phenyl, 3: phenoxy, 4: benzoyl, and 5: benzyl). The principal synthetic approach for the desired compounds consisted of a Wittig olefination between 1, 4-dioxaspiro [4.5]-decane-8-carbaldehyde (4g and the appropriate phosphonium salts. The compounds were tested for inhibition of human 5 alpha reductase isozymes 1 and 2 using DU 145 cells and preparations from prostatic tissue, respectively. They turned out to be good inhibitors of the prostatic isozyme 2 with compound 1 being the most potent one (IC(50) = 760 nM). Isozyme 1 was only slightly inhibited. It is concluded that the novel structures are appropriate for being further optimized, aiming at the development of a novel drug for the treatment of benign prostatic hyperplasia.

  6. Facile syntheses of isotope-labeled chiral octahydroindole-2-carboxylic acid and its N-methyl analog

    International Nuclear Information System (INIS)

    Yinsheng Zhang

    2012-01-01

    We have synthesized deuterium and carbon-14 labeled enantiomerically pure octahydroindole-2-carboxylic acid (PD0140417), N-methyl octahydroindole-2-carboxylic acid (PD0348183) and their racemic analogs (PD0108405 and PD0338055). [ring-U- 14 C]PD0140417 was prepared from [ring-U- 14 C]benzoic acid in a seven-step synthesis in 6.2% overall radiochemical yield. [ 14 C]PD0348183 was prepared from [ 14 C]BaCO 3 in a five-step synthesis in 16% radiochemical yield. Additionally, [D]PD0108405 and [D]PD0338055 were synthesized by direct platinum-catalyzed hydrogenation with deuterium gas. (author)

  7. Sorption and pertechnetate by salts of molybdophosphoric acid

    International Nuclear Information System (INIS)

    Suess, M.; Pfrepper, G.

    1983-01-01

    The sorption of pertechnetate on salts of molybdophosphoric acid from nitric acid and in the presence of electrolytes was investigated. Distribution coefficients from 10 to 100 ml/g were found. The sorption of pertechnetate can be increased by the addition of K + , NH 4 + , Rb + and Cs + salts. A saturation capacity of proportional 0,19 mmol/g ammonium phosphomolybdate was found from the adsorption isotherms. The formation of alkali metal pertechnetate associates in the sorbent phase is supposed. (orig.)

  8. Ethylene biosynthesis by 1-aminocyclopropane-1-carboxylic acid oxidase: a DFT study.

    Science.gov (United States)

    Bassan, Arianna; Borowski, Tomasz; Schofield, Christopher J; Siegbahn, Per E M

    2006-11-24

    The reaction catalyzed by the plant enzyme 1-aminocyclopropane-1-carboxylic acid oxidase (ACCO) was investigated by using hybrid density functional theory. ACCO belongs to the non-heme iron(II) enzyme superfamily and carries out the bicarbonate-dependent two-electron oxidation of its substrate ACC (1-aminocyclopropane-1-carboxylic acid) concomitant with the reduction of dioxygen and oxidation of a reducing agent probably ascorbate. The reaction gives ethylene, CO(2), cyanide and two water molecules. A model including the mononuclear iron complex with ACC in the first coordination sphere was used to study the details of O-O bond cleavage and cyclopropane ring opening. Calculations imply that this unusual and complex reaction is triggered by a hydrogen atom abstraction step generating a radical on the amino nitrogen of ACC. Subsequently, cyclopropane ring opening followed by O-O bond heterolysis leads to a very reactive iron(IV)-oxo intermediate, which decomposes to ethylene and cyanoformate with very low energy barriers. The reaction is assisted by bicarbonate located in the second coordination sphere of the metal.

  9. Acid monomer analysis in waterborne polymer systems by targeted labeling of carboxylic acid functionality, followed by pyrolysis - gas chromatography.

    Science.gov (United States)

    Brooijmans, T; Okhuijsen, R; Oerlemans, I; Schoenmakers, P J; Peters, R

    2018-05-14

    Pyrolysis - gas chromatography - (PyGC) is a common method to analyse the composition of natural and synthetic resins. The analysis of acid functionality in, for example, waterborne polyacrylates and polyurethanes polymers has proven to be difficult due to solubility issues, inter- and intramolecular interaction effects, lack of detectability in chromatographic analysis, and lack of thermal stability. Conventional analytical techniques, such as PyGC, cannot be used for the direct detection and identification of acidic monomers, due to thermal rearrangements that take place during pyrolysis. To circumvent this, the carboxylic acid groups are protected prior to thermal treatment by reaction with 2-bromoacetophenone. Reaction conditions are investigated and optimised wrt. conversion measurements. The aproach is applied to waterborne polyacryalates and the results are discussed. This approach enables identification and (semi)quantitative analysis of different acid functionalities in waterborne polymers by PyGC. Copyright © 2018 Elsevier B.V. All rights reserved.

  10. Separation of aliphatic carboxylic acids and benzenecarboxylic acids by ion-exclusion chromatography with various cation-exchange resin columns and sulfuric acid as eluent.

    Science.gov (United States)

    Ohta, Kazutoku; Ohashi, Masayoshi; Jin, Ji-Ye; Takeuchi, Toyohide; Fujimoto, Chuzo; Choi, Seong-Ho; Ryoo, Jae-Jeong; Lee, Kwang-Pill

    2003-05-16

    The application of various hydrophilic cation-exchange resins for high-performance liquid chromatography (sulfonated silica gel: TSKgel SP-2SW, carboxylated silica gel: TSKgel CM-2SW, sulfonated polymethacrylate resin: TSKgel SP-5PW, carboxylated polymethacrylate resins: TSKgel CM-5PW and TSKgel OA-Pak A) as stationary phases in ion-exclusion chromatography for C1-C7 aliphatic carboxylic acids (formic, acetic, propionic, butyric, isovaleric, valeric, isocaproic, caproic, 2-methylhexanoic and heptanoic acids) and benzenecarboxylic acids (pyromellitic, trimellitic, hemimellitic, o-phthalic, m-phthalic, p-phthalic, benzoic, salicylic acids and phenol) was carried out using diluted sulfuric acid as the eluent. Silica-based cation-exchange resins (TSKgel SP-2SW and TSKgel CM-2SW) were very suitable for the ion-exclusion chromatographic separation of these benzenecarboxylic acids. Excellent simultaneous separation of these benzenecarboxylic acids was achieved on a TSKgel SP-2SW column (150 x 6 mm I.D.) in 17 min using a 2.5 mM sulfuric acid at pH 2.4 as the eluent. Polymethacrylate-based cation-exchange resins (TSKgel SP-5PW, TSKgel CM-5PW and TSKgel OA-Pak A) acted as advanced stationary phases for the ion-exclusion chromatographic separation of these C1-C7 aliphatic carboxylic acids. Excellent simultaneous separation of these C1-C7 acids was achieved on a TSKgel CM-5PW column (150 x 6 mm I.D.) in 32 min using a 0.05 mM sulfuric acid at pH 4.0 as the eluent.

  11. An acridinium sulphonylamide as a new chemiluminescent label for the determination of carboxylic acids in liquid chromatography

    NARCIS (Netherlands)

    Steijger, O.M.; Kamminga, D.A.; Lingeman, H.; Brinkman, U.A.T.

    1998-01-01

    The synthesis of a new acridinium sulphonylamide label for the liquid chromatographic determination of carboxylic acids is described. The label 10-methyl-N-(p-tolyl)-N-(p-iodoacetamidobenzenesulphonyl)-9-acridinium carboxamide iodide is synthesized from 9-acridinecarboxylic acid by a seven-step

  12. Electrochemical properties of polyolefin nonwoven fabric modified with carboxylic acid group for battery separator

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Seong-Ho; Kang, Hae-Jeong; Ryu, Eun-Nyoung; Lee, Kwang-Pill E-mail: kplee@kyungpook.ac.kr

    2001-07-01

    Carboxylic acid group was introduced by radiation-induced grafting of acrylic acid (AAc) onto polyolefine nonwoven fabric (PNF), wherein the PNF comprises at least about 60% of a polyethylene having a melting temperature at {approx}132 deg. C and no more than about 40% of a second polypropylene having a lower melting temperature at {approx}162 deg. C, for a battery separator. The AAc-grafted PNF was characterized by XPS, SEM, DSC, TGA and porosimeter. The wetting speed, electrolyte retention, electrical resistance, and tensile strength were evaluated after grafting of AAc. It was found that the wetting speed, electrolyte retention, thickness, and ion-exchange capacity increased, whereas the electrical resistance decreased with increasing grafting yield. The tensile strength decreased with increasing grafting yield, whereas the elongation decreased with increasing grafting yield. (author)

  13. Electrochemical properties of polyolefine nonwoven fabric modified with carboxylic acid group for battery separator

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Seong-Ho; Park, Keung-Shik; Kang, Hae-Jeong; Ryu, Eun-Nyoung; Lee, Pill-Kwang [Department of Chemistry Graduate School, Kyungpook National University, Taegu (Korea)

    2000-07-01

    Carboxylic acid group was introduced by radiation-induced grafting of acrylic acid (AAc) onto polyolefine nonwoven fabric (PNF), wherein the PNF comprises at least about 60% of a polyethylene having a melting temperature at {approx}132degC and no more than about 40% of a second polypropylene having a lower melting temperature at {approx}162degC, for a battery separator. The AAc-grafted PNF was characterized by XPS, SEM, DSC, TGA and porosimeter. The wetting speed, electrolyte retention, electrical resistance, and tensile strength were evaluated after grafting of AAc. It was found that the wetting speed, electrolyte retention, thickness, and ion-exchange capacity increased, whereas the electrical resistance decreased with increasing grafting yield. The tensile strength decreased with increasing grafting yield, whereas the elongation decreased with increasing grafting yield. (author)

  14. Electrocatalytic carboxylation of chloroacetonitrile at a silver cathode for the synthesis of cyanoacetic acid

    Energy Technology Data Exchange (ETDEWEB)

    Scialdone, Onofrio [Dipartimento di Ingegneria Chimica dei Processi e dei Materiali, Universita di Palermo, Viale delle Scienze, 90128 Palermo (Italy)], E-mail: scialdone@dicpm.unipa.it; Galia, Alessandro; Filardo, Giuseppe [Dipartimento di Ingegneria Chimica dei Processi e dei Materiali, Universita di Palermo, Viale delle Scienze, 90128 Palermo (Italy); Isse, Abdirisak Ahmed [Dipartimento di Scienze Chimiche, Universita di Padova, Via Marzolo 1, 35131 Padova (Italy)], E-mail: Abdirisak.ahmedisse@unipd.it; Gennaro, Armando [Dipartimento di Scienze Chimiche, Universita di Padova, Via Marzolo 1, 35131 Padova (Italy)

    2008-12-30

    The electrocatalytic carboxylation of chloroacetonitrile to cyanoacetic acid performed at silver cathodes was investigated both theoretically and experimentally. Silver exhibits powerful electrocatalytic activities towards the reduction of chloroacetonitrile. In CO{sub 2}-saturated CH{sub 3}CN, reduction of NCCH{sub 2}Cl occurs at potentials that are about 0.7 V more positive than those observed at glassy carbon and gives cyanoacetic acid in good yields. Theoretical considerations on the effect of operative parameters on the performances of the process were confirmed by electrocarboxylation experiments performed in undivided cells equipped with sacrificial anodes both in a bench-scale electrochemical batch reactor and in a continuous batch recirculation reaction system equipped with a parallel plate electrochemical cell. Selectivities and Faradic efficiencies higher than 80% were obtained by working under anhydrous conditions both under amperostatic and potentiostatic alimentation at proper values of either current density or applied potential.

  15. Conjugates of 1'-Aminoferrocene-1-carboxylic Acid and Proline: Synthesis, Conformational Analysis and Biological Evaluation

    Directory of Open Access Journals (Sweden)

    Monika Kovačević

    2014-08-01

    Full Text Available Our previous studies showed that alteration of dipeptides Y-Fca-Ala-OMe (III into Y-Ala-Fca-OMe (IV (Y = Ac, Boc; Fca = 1'-aminoferrocene-1-carboxylic acid significantly influenced their conformational space. The novel bioconjugates Y-Fca-Pro-OMe (1, Y = Ac; 2, Y = Boc and Y-Pro-Fca-OMe (3, Y = Boc; 4, Y = Ac have been prepared in order to investigate the influence of proline, a well-known turn-inducer, on the conformational properties of small organometallic peptides with an exchanged constituent amino acid sequences. For this purpose, peptides 1–4 were subjected to detailed spectroscopic analysis (IR, NMR, CD spectroscopy in solution. The conformation of peptide 3 in the solid state was determined. Furthermore, the ability of the prepared conjugates to inhibit the growth of estrogen receptor-responsive MCF-7 mammary carcinoma cells and HeLa cervical carcinoma cells was tested.

  16. Synthesis and Structural Characterization of 1- and 2-Substituted Indazoles: Ester and Carboxylic Acid Derivatives

    Directory of Open Access Journals (Sweden)

    Isabel Bento

    2006-11-01

    Full Text Available A series of indazoles substituted at the N-1 and N-2 positions with ester-containing side chains -(CH2nCO2R of different lengths (n = 0-6, 9, 10 are described.Nucleophilic substitution reactions on halo esters (X(CH2nCO2R by 1H-indazole inalkaline solution lead to mixtures of N-1 and N-2 isomers, in which the N-1 isomerpredominates. Basic hydrolysis of the ester derivatives allowed the synthesis of thecorresponding indazole carboxylic acids. All compounds were fully characterised bymultinuclear NMR and IR spectroscopies, MS spectrometry and elemental analysis; theNMR spectroscopic data were used for structural assignment of the N-1 and N-2 isomers.The molecular structure of indazol-2-yl-acetic acid (5b was determined by X-raydiffraction, which shows a supramolecular architecture involving O2-H...N1intermolecular hydrogen bonds.

  17. Radiation-initiated emulsion copolymerization of styrene and carboxylic acid monomers

    International Nuclear Information System (INIS)

    Egusa, S.; Makuuchi, K.

    1982-01-01

    The emulsion copolymerization of styrene and carboxylic acid monomers such as acrylic, methacrylic, and itaconic acids (AAc, MAAc, IAc) was studied by using 60 Co γ-rays as initiator and sodium dodecylsulfate as emulsifier. The polymerization behavior of these acid monomers was followed by simultaneous conductometric and potentiometric titrations for a latex sample taken in polymerization. The polymerization rate of these acid monomers increases in the following order of hydrophobicity: IAc < AAc < MAAc; this suggests that their polymerization sites are mainly the surface and/or subsurface regions of latex particles. The copolymerization rate of styrene and acid monomer increases with an increase in the acid monomer content for AAc and MAAc, whereas for IAc the rate decreases. The particle sizes determined by the stopped-flow method reveal that this variation of copolymerization rate cannot be explained by the number of growing particles and should be attributed to another factor; for instance, the transfer rate of styrene molecules from oil droplets to growing particles

  18. Ion-exclusion chromatography with conductimetric detection of aliphatic carboxylic acids on a weakly acidic cation-exchange resin by elution with benzoic acid-beta-cyclodextrin.

    Science.gov (United States)

    Tanaka, Kazuhiko; Mori, Masanobu; Xu, Qun; Helaleh, Murad I H; Ikedo, Mikaru; Taoda, Hiroshi; Hu, Wenzhi; Hasebe, Kiyoshi; Fritz, James S; Haddad, Paul R

    2003-05-16

    In this study, an aqueous solution consisting of benzoic acid with low background conductivity and beta-cyclodextrin (beta-CD) of hydrophilic nature and the inclusion effect to benzoic acid were used as eluent for the ion-exclusion chromatographic separation of aliphatic carboxylic acids with different pKa values and hydrophobicity on a polymethacrylate-based weakly acidic cation-exchange resin in the H+ form. With increasing concentration of beta-cyclodextrin in the eluent, the retention times of the carboxylic acids decreased due to the increased hydrophilicity of the polymethacrylate-based cation-exchange resin surface from the adsorption of OH groups of beta-cyclodextrin. Moreover, the eluent background conductivity decreased with increasing concentration of beta-cyclodextrin in 1 mM benzoic acid, which could result in higher sensitivity for conductimetric detection. The ion-exclusion chromatographic separation of carboxylic acids with high resolution and sensitivity was accomplished successfully by elution with a 1 mM benzoic acid-10 mM cyclodextrin solution without chemical suppression.

  19. Acid-Base Behavior of Carboxylic Acid Groups Covalently Attached at the Surface of Polyethylene: The Usefulness of Contact Angle in Following the Ionization of Surface Functionality

    Science.gov (United States)

    1985-08-01

    additional check, we converted granular PE-CO 2H to granular PE-CO 2CH3 by acid -catalyzed esterification. This material had no titrable groups. Upon...Task No. NR-631-840 TECHNICAL REPORT NO. 85-1 Acid -Base Behavior of Carboxylic Acid Groups Covalently Attached at the Surface of Polyethylene: The...34I Acid -Base Behavior K-142 ofCarboxylicAcidGroupsAttached...______________________ 12. PERSIIMAL AUTHOR IS) S.R. Holmes-Farly., R.H. Reamey, T.J

  20. Stereospecific synthesis of syn-α-oximinoamides by a three-component reaction of isocyanides, syn-chlorooximes, and carboxylic acids.

    Science.gov (United States)

    Pirali, Tracey; Mossetti, Riccardo; Galli, Simona; Tron, Gian Cesare

    2011-07-15

    A stereospecific multicomponent reaction among isocyanides, syn-chlorooximes, and carboxylic acids provides an efficient synthesis of biologically relevant syn-α-oximinoamides. © 2011 American Chemical Society

  1. Degradation of chitosan hydrogel dispersed in dilute carboxylic acids by solution plasma and evaluation of anticancer activity of degraded products

    Science.gov (United States)

    Chokradjaroen, Chayanaphat; Rujiravanit, Ratana; Theeramunkong, Sewan; Saito, Nagahiro

    2018-01-01

    Chitosan is a polysaccharide that has been extensively studied in the field of biomedicine, especially its water-soluble degraded products called chitooligosaccharides (COS). In this study, COS were produced by the degradation of chitosan hydrogel dispersed in a dilute solution (i.e., 1.55 mM) of various kinds of carboxylic acids using a non-thermal plasma technology called solution plasma (SP). The degradation rates of chitosan were influenced by the type of carboxylic acids, depending on the interaction between chitosan and each carboxylic acid. After SP treatment, the water-soluble degraded products containing COS could be easily separated from the water-insoluble residue of chitosan hydrogel by centrifugation. The production yields of the COS were mostly higher than 55%. Furthermore, the obtained COS products were evaluated for their inhibitory effect as well as their selectivity against human lung cancer cells (H460) and human lung normal cells (MRC-5).

  2. RECOVERY OF CARBOXYLIC ACIDS FROM AQUEOUS SOLUTIONS BY LIQUID-LIQUID EXTRACTION WITH A TRIISOOCTYLAMINE DILUENT SYSTEM

    Directory of Open Access Journals (Sweden)

    G. Malmary

    2001-12-01

    Full Text Available Tertiary alkylamines in solution with organic diluents are attractive extractants for the recovery of carboxylic acids from dilute aqueous phases. The aim of this study was to investigate the mechanism for extraction of organic acids from water by a long-chain aliphatic tertiary amine. In order to attain this objective, we studied the liquid-liquid equilibria between the triisooctylamine + 1-octanol + n-heptane system as solvent and an aqueous solution of an individual carboxylic acid such as citric, lactic and malic acids. The experiments showed that the partition coefficient for a particular organic acid depends on the kind of solute, notably when the acid concentration in the aqueous phase is low. A mathematical model, where both chemical association and physical distribution are taken into consideration, is proposed. The model suggests that the various complexes obtained between amine and organic acids contribute to the distribution of the solute between the coexisting phases in equilibrium.

  3. Novel Isoniazid cocrystals with aromatic carboxylic acids: Crystal engineering, spectroscopy and thermochemical investigations

    Science.gov (United States)

    Diniz, Luan F.; Souza, Matheus S.; Carvalho, Paulo S.; da Silva, Cecilia C. P.; D'Vries, Richard F.; Ellena, Javier

    2018-02-01

    Four novel cocrystals of the anti-tuberculosis drug Isoniazid (INH), including two polymorphs, with the aromatic carboxylic acids p-nitrobenzoic (PNBA), p-cyanobenzoic (PCNBA) and p-aminobenzoic (PABA) were rationally designed and synthesized by solvent evaporation. Aiming to explore the possible supramolecular synthons of this API, these cocrystals were fully characterized by X-ray diffraction (SCXRD, PXRD), spectroscopic (FT-IR) and thermal (TGA, DSC, HSM) techniques. The cocrystal formation was found to be mainly driven by the synthons formed by the pyridine and hydrazide moieties. In both INH-PABA polymorphs, the COOH acid groups are H-bonded to pyridine and hydrazide groups giving rise to the acid⋯pyridine and acid⋯hydrazide heterosynthons. In INH-PNBA and INH-PCNBA cocrystals these acid groups are only related to the pyridine moiety. In addition to the structural study, supramolecular and Hirshfeld surface analysis were also performed based on the structural data. The cocrystals were identified from the FT-IR spectra and their thermal behaviors were studied by a combination of DSC, TGA and HSM techniques.

  4. Corrosion of stainless steel in alcohol solutions of the simplest carboxylic acids

    International Nuclear Information System (INIS)

    Vigdorovich, V.I.; Korneeva, T.V.; Tsygankova, L.E.

    1975-01-01

    The behaviour of stainless Kh18N10T steel is considered in the methanol and ethanol solutions of formic and acetic acids, respectively. Consideration is given to the effect of the concentration (C) of the acid (0.01-1.00 N), water (0.1-20.0 mass.%) and temperature (room temperature, 40 and 60 deg C). Curves of anodic polarization were plotted. In the course of time in 1.0 and 0.5 N anhydrous methanol solutions of HCOOH at room temperature in the absence of the external anode current one can observe an increase in the electrode potential. Continued reduction of the formic acid concentration results in an improvement on the initial potential (psi) and a practical constancy of psi in time. It is shown that depending on the acid concentration the additions of water are capable of producing both a passivating and an activating effect. It is assumed that the growth in the length of the hydrocarbon radical of carboxylic acid promotes the adsorption displacement of water and alcohols from the metal surface and enhancement of the corrosion rate

  5. Anti-Inflammatory and Antinociceptive Activities of Anthraquinone-2-Carboxylic Acid.

    Science.gov (United States)

    Park, Jae Gwang; Kim, Seung Cheol; Kim, Yun Hwan; Yang, Woo Seok; Kim, Yong; Hong, Sungyoul; Kim, Kyung-Hee; Yoo, Byong Chul; Kim, Shi Hyung; Kim, Jong-Hoon; Cho, Jae Youl

    2016-01-01

    Anthraquinone compounds are one of the abundant polyphenols found in fruits, vegetables, and herbs. However, the in vivo anti-inflammatory activity and molecular mechanisms of anthraquinones have not been fully elucidated. We investigated the activity of anthraquinones using acute inflammatory and nociceptive experimental conditions. Anthraquinone-2-carboxylic acid (9,10-dihydro-9,10-dioxo-2-anthracenecarboxylic acid, AQCA), one of the major anthraquinones identified from Brazilian taheebo, ameliorated various inflammatory and algesic symptoms in EtOH/HCl- and acetylsalicylic acid- (ASA-) induced gastritis, arachidonic acid-induced edema, and acetic acid-induced abdominal writhing without displaying toxic profiles in body and organ weight, gastric irritation, or serum parameters. In addition, AQCA suppressed the expression of inflammatory genes such as cyclooxygenase- (COX-) 2 in stomach tissues and lipopolysaccharide- (LPS-) treated RAW264.7 cells. According to reporter gene assay and immunoblotting analyses, AQCA inhibited activation of the nuclear factor- (NF-) κB and activator protein- (AP-) 1 pathways by suppression of upstream signaling involving interleukin-1 receptor-associated kinase 4 (IRAK1), p38, Src, and spleen tyrosine kinase (Syk). Our data strongly suggest that anthraquinones such as AQCA act as potent anti-inflammatory and antinociceptive components in vivo, thus contributing to the immune regulatory role of fruits and herbs.

  6. The effects of solvents and structure on the electronic absorption spectra of the isomeric pyridine carboxylic acid N-oxides

    Directory of Open Access Journals (Sweden)

    Drmanić Saša Ž.

    2013-01-01

    Full Text Available The ultraviolet absorption spectra of the carboxyl group of three isomeric pyridine carboxylic acids N-oxides (picolinic acid N-oxide, nicotinic acid N-oxide and isonicotinic acid N-oxide were determined in fourteen solvents in the wavelength range from 200 to 400 nm. The position of the absorption maxima (λmax of the examined acids showed that the ultraviolet absorption maximum wavelengths of picolinic acid N-oxide are the shortest, and those of isonicotinic acid N-oxide acid are the longest. In order to analyze the solvent effect on the obtained absorption spectra, the ultraviolet absorption frequencies of the electronic transitions in the carboxylic group of the examined acids were correlated using a total solvatochromic equation of the form max = v0 + sπ + aα+ bβ, where υmax is the absorption frequency (1/λmax, p is a measure of the solvent polarity, β represents the scale of solvent hydrogen bond acceptor basicities and α represent the scale of solvent hydrogen bond donor acidities. The correlation of the spectroscopic data was carried out by means of multiple linear regression analysis. The solvent effects on the ultraviolet absorption maximums of the examined acids were discussed.

  7. Thermodynamic studies on corrosion inhibition of aqueous solutions of amino/carboxylic acids toward copper by EMF measurement

    International Nuclear Information System (INIS)

    Spah, Manjula; Spah, Dal Chand; Deshwal, Balraj; Lee, Seungmoon; Chae, Yoon-Keun; Park, Jin Won

    2009-01-01

    Electromotive force (E) measurements were made on an electrochemical cell [Cu x Hg|CuCl 2 (m) in a solvent S|AgCl-Ag] (where S is a dilute aqueous solution (0.01 m) of amino acid (glycine, alanine, methionine and glutamic acid) or aliphatic carboxylic acid (formic acid, acetic acid, n-butyric acid and glutaric acid)) at 30 deg. C. These measured E values were used to compute the dissociation constants (K 1 and K 2 ) and the degree of dissociation (α 1 and α 2 ) by iterative procedures. The standard cell potential (E o ) and the mean activity coefficient (γ ± ) of CuCl 2 were also determined. The E o data were next used to evaluate the Gibbs energy of transfer (ΔG tr 0 ) of CuCl 2 from water to dilute aqueous solutions of the amino/carboxylic acids. The negative ΔG tr 0 values suggested that these acids act as potential corrosion inhibitors. The magnitudes of ΔG tr 0 values show that the amino acids act as better corrosion inhibitors towards copper than the aliphatic carboxylic acids.

  8. A structural and functional model for the 1-aminocyclopropane-1-carboxylic acid oxidase.

    Science.gov (United States)

    Sallmann, Madleen; Oldenburg, Fabio; Braun, Beatrice; Réglier, Marius; Simaan, A Jalila; Limberg, Christian

    2015-10-12

    The hitherto most realistic low-molecular-weight analogue for the 1-aminocyclopropane-1-carboxylic acid oxidase (ACCO) is reported. The ACCOs 2-His-1-carboxylate iron(II) active site was mimicked by a TpFe moiety, to which the natural substrate ACC could be bound. The resulting complex [Tp(Me,Ph) FeACC] (1), according to X-ray diffraction analysis performed for the nickel analogue, represents an excellent structural model, featuring ACC coordinated in a bidentate fashion-as proposed for the enzymatic substrate complex-as well as a vacant coordination site that forms the basis for the first successful replication also of the ACCO function: 1 is the first known ACC complex that reacts with O2 to produce ethylene. As a FeOOH species had been suggested as intermediate in the catalytic cycle, H2 O2 was tested as the oxidant, too, and indeed evolution of ethylene proceeded even more rapidly to give 65 % yield. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Experimental and theoretical elucidation of structural and antioxidant properties of vanillylmandelic acid and its carboxylate anion

    Science.gov (United States)

    Dimić, Dušan; Milenković, Dejan; Ilić, Jelica; Šmit, Biljana; Amić, Ana; Marković, Zoran; Dimitrić Marković, Jasmina

    2018-06-01

    Vanillylmandelic acid (VMA), an important metabolite of catecholamines that is routinely screened as tumor marker, was investigated by the various spectroscopic techniques (IR, Raman, UV-Vis, antioxidant decolorization assay and NMR). Structures optimized by the employment of five common functionals (M05-2X, M06-2X, B3LYP, CAM-B3LYP, B3LYP-D3) were compared with the crystallographic data. The M05-2X functional reproduced the most reliable experimental bond lengths and angles (correlation coefficient >0.999). The importance of intramolecular hydrogen bonds for structural stability was discussed and quantified by the NBO analysis. The most prominent bands in vibrational spectrum were analyzed and compared to the experimental data. The positions of the carbon and hydrogen atoms in NMR spectra were well reproduced. The differences in UV-Vis spectrum were investigated by adding the explicit solvent and by performing NBO and QTAIM analyses. The discrepancy in the two spectra of about 50 nm could be explained by the solvent effect on carboxyl group. The most probable antioxidant activity mechanism was discussed for VMA and its carboxylate anion. The Molecular Docking study with the C - reactive protein additionally proved that variety of functional groups present in VMA and its anion allowed strong hydrogen and hydrophobic interactions.

  10. Simultaneous determination of dopamine, uric acid and nitrite using carboxylated graphene oxide/lanthanum modified electrode

    International Nuclear Information System (INIS)

    Ye, Fengying; Feng, Chenqi; Jiang, Jibo; Han, Sheng

    2015-01-01

    Highlights: • The carboxylated graphene oxide/lanthanum-modified glassy carbon electrode (GO-COOLa/GCE) was successfully utilized for the simultaneous detection and quantification of DA, UA and NO 2 − . • Combining the benefits of carboxylated graphene oxide and lanthanum, the modified sensor displayed large peak separations, long linear ranges and low detection limits for simultaneously detecting DA, UA and NO 2 − . • The GO-COOLa/GCE electrode showed well stability, good repeatability, rapid response, and high catalytic performance toward the oxidations of DA, UA and NO 2 − . - Abstract: A bare glassy carbon electrode (GCE) was reformed by carboxylated graphene oxide/lanthanum, and the modified electrode, called GO-COOLa/GCE, was fabricated for simultaneously detecting dopamine (DA), uric acid (UA) and nitrite (NO 2 − ) by cyclic voltammetry (CV), differential pulse voltammetry (DPV) and amperometry. Several factors which affected the electrocatalytic activity of the GO-COOLa/GCE electrode, such as the effect of pH, scan rate and concentration were studied. Due to the combination of carboxylated graphene oxide and lanthanum ions, the GO-COOLa/GCE sensor showed rapid response, excellent selectivity and high catalytic performance toward the electrooxidation of DA, UA and NO 2 − . In optimized conditions, two linear response ranges for determining DA were obtained over ranges of 0.01-1.96×10 2 μM and 1.96×10 2 -1.23×10 3 μM with detection limit of 0.018 μM (S/N = 3). And the responses of the GO-COOLa/GCE electrode for UA and NO 2 − were linear in the region of 1-1.53×10 3 μM and 1-2.75×10 3 μM with detection limits of 0.058 μM and 0.070 μM, respectively. Furthermore, this reformed electrode was successfully used to the detection of DA, UA and NO 2 − in real urine and serum samples, showing its promising application in the electroanalysis of real samples.

  11. Synthesis and Transformations of di-endo-3-Aminobicyclo-[2.2.2]oct-5-ene-2-carboxylic Acid Derivatives

    Directory of Open Access Journals (Sweden)

    Márta Palkó

    2011-09-01

    Full Text Available all-endo-3-amino-5-hydroxybicyclo[2.2.2]octane-2-carboxylic acid (13 and all-endo-5-amino-6-(hydroxymethylbicyclo[2.2.2]octan-2-ol (10 were prepared via dihydro-1,3-oxazine or g-lactone intermediates by the stereoselective functionalization of an N-protected derivative of endo-3-aminobicyclo[2.2.2]oct-5-ene-2-carboxylic acid (2. Ring closure of b-amino ester 4 resulted in tricyclic pyrimidinones 15 and 16. The structures, stereochemistry and relative configurations of the synthesized compounds were determined by IR and NMR.

  12. Organocatalyzed, Visible-Light Photoredox-Mediated, One-Pot Minisci Reaction Using Carboxylic Acids via N-(Acyloxy)phthalimides.

    Science.gov (United States)

    Sherwood, Trevor C; Li, Ning; Yazdani, Aliza N; Dhar, T G Murali

    2018-03-02

    An improved, one-pot Minisci reaction has been developed using visible light, an organic photocatalyst, and carboxylic acids as radical precursors via the intermediacy of in situ-generated N-(acyloxy)phthalimides. The conditions employed are mild, demonstrate a high degree of functional group tolerance, and do not require a large excess of the carboxylic acid reactant. As a result, this reaction can be applied to drug-like scaffolds and molecules with sensitive functional groups, enabling late-stage functionalization, which is of high interest to medicinal chemistry.

  13. Are carboxyl groups the most acidic sites in amino acids? Gas-phase acidities, photoelectron spectra, and computations on tyrosine, p-hydroxybenzoic acid, and their conjugate bases.

    Science.gov (United States)

    Tian, Zhixin; Wang, Xue-Bin; Wang, Lai-Sheng; Kass, Steven R

    2009-01-28

    Deprotonation of tyrosine in the gas phase was found to occur preferentially at the phenolic site, and the conjugate base consists of a 70:30 mixture of phenoxide and carboxylate anions at equilibrium. This result was established by developing a chemical probe for differentiating these two isomers, and the presence of both ions was confirmed by photoelectron spectroscopy. Equilibrium acidity measurements on tyrosine indicated that deltaG(acid)(o) = 332.5 +/- 1.5 kcal mol(-1) and deltaH(acid)(o) = 340.7 +/- 1.5 kcal mol(-1). Photoelectron spectra yielded adiabatic electron detachment energies of 2.70 +/- 0.05 and 3.55 +/- 0.10 eV for the phenoxide and carboxylate anions, respectively. The H/D exchange behavior of deprotonated tyrosine was examined using three different alcohols (CF3CH2OD, C6H5CH2OD, and CH3CH2OD), and incorporation of up to three deuterium atoms was observed. Two pathways are proposed to account for these results, and all of the experimental findings are supplemented with B3LYP/aug-cc-pVDZ and G3B3 calculations. In addition, it was found that electrospray ionization of tyrosine from a 3:1 (v/v) CH3OH/H2O solution using a commercial source produces a deprotonated [M-H]- anion with the gas-phase equilibrium composition rather than the structure of the ion that exists in aqueous media. Electrospray ionization from acetonitrile, however, leads largely to the liquid-phase (carboxylate) structure. A control molecule, p-hydroxybenzoic acid, was found to behave in a similar manner. Thus, the electrospray conditions that are employed for the analysis of a compound can alter the isomeric composition of the resulting anion.

  14. A Novel Approach in Cinnamic Acid Synthesis: Direct Synthesis of Cinnamic Acids from Aromatic Aldehydes and Aliphatic Carboxylic Acids in the Presence of Boron Tribromide

    Directory of Open Access Journals (Sweden)

    M. Onciu

    2005-02-01

    Full Text Available Cinnamic acids have been prepared in moderate to high yields by a new direct synthesis using aromatic aldehydes and aliphatic carboxylic acids, in the presence of boron tribromide as reagent, 4-dimethylaminopyridine (4-DMAP and pyridine (Py as bases and N-methyl-2-pyrolidinone (NMP as solvent, at reflux (180-190°C for 8-12 hours.

  15. Chemical rescue of the post-translationally carboxylated lysine mutant of allantoinase and dihydroorotase by metal ions and short-chain carboxylic acids.

    Science.gov (United States)

    Ho, Ya-Yeh; Huang, Yen-Hua; Huang, Cheng-Yang

    2013-04-01

    Bacterial allantoinase (ALLase) and dihydroorotase (DHOase) are members of the cyclic amidohydrolase family. ALLase and DHOase possess similar binuclear metal centers in the active site in which two metals are bridged by a post-translationally carboxylated lysine. In this study, we determined the effects of carboxylated lysine and metal binding on the activities of ALLase and DHOase. Although DHOase is a metalloenzyme, purified DHOase showed high activity without additional metal supplementation in a reaction mixture or bacterial culture. However, unlike DHOase, ALLase had no activity unless some specific metal ions were added to the reaction mixture or culture. Substituting the metal binding sites H59, H61, K146, H186, H242, or D315 with alanine completely abolished the activity of ALLase. However, the K146C, K146D and K146E mutants of ALLase were still active with about 1-6% activity of the wild-type enzyme. These ALLase K146 mutants were found to have 1.4-1.7 mol metal per mole enzyme subunit, which may indicate that they still contained the binuclear metal center in the active site. The activity of the K146A mutant of the ALLase and the K103A mutant of DHOase can be chemically rescued by short-chain carboxylic acids, such as acetic, propionic, and butyric acids, but not by ethanol, propan-1-ol, and imidazole, in the presence of Co2+ or Mn2+ ions. However, the activity was still ~10-fold less than that of wild-type ALLase. Overall, these results indicated that the 20 natural basic amino acid residues were not sufficiently able to play the role of lysine. Accordingly, we proposed that during evolution, the post-translational modification of carboxylated lysine in the cyclic amidohydrolase family was selected for promoting binuclear metal center self-assembly and increasing the nucleophilicity of the hydroxide at the active site for enzyme catalysis. This kind of chemical rescue combined with site-directed mutagenesis may also be used to identify a binuclear metal

  16. Surface Patterning of Benzene Carboxylic Acids on Graphite: Influence of structure, solvent, and concentration on molecular self-assembly

    Science.gov (United States)

    Florio, Gina; Stiso, Kimberly; Campanelli, Joseph; Dessources, Kimberly; Folkes, Trudi

    2012-02-01

    Scanning tunneling microscopy (STM) was used to investigate the molecular self-assembly of four different benzene carboxylic acid derivatives at the liquid/graphite interface: pyromellitic acid (1,2,4,5-benzenetetracarboxylic acid), trimellitic acid (1,2,4-benzenetricarboxylic acid), trimesic acid (1,3,5-benzenetricarboxylic acid), and 1,3,5-benzenetriacetic acid. A range of two dimensional networks are observed that depend sensitively on the number of carboxylic acids present, the nature of the solvent, and the solution concentration. We will describe our recent efforts to determine (a) the preferential two-dimensional structure(s) for each benzene carboxylic acid at the liquid/graphite interface, (b) the thermodynamic and kinetic factors influencing self-assembly (or lack thereof), (c) the role solvent plays in the assembly, (e) the effect of in situ versus ex situ dilution on surface packing density, and (f) the temporal evolution of the self-assembled monolayer. Results of computational analysis of analog molecules and model monolayer films will also be presented to aid assignment of network structures and to provide a qualitative picture of surface adsorption and network formation.

  17. 40 CFR 721.1930 - Butanoic acid, antimony (3=) salt.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Butanoic acid, antimony (3=) salt. 721.1930 Section 721.1930 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.1930 Butanoic acid,...

  18. Molecular Design of a Chiral Brønsted Acid with Two Different Acidic Sites: Regio-, Diastereo-, and Enantioselective Hetero-Diels-Alder Reaction of Azopyridinecarboxylate with Amidodienes Catalyzed by Chiral Carboxylic Acid-Monophosphoric Acid.

    Science.gov (United States)

    Momiyama, Norie; Tabuse, Hideaki; Noda, Hirofumi; Yamanaka, Masahiro; Fujinami, Takeshi; Yamanishi, Katsunori; Izumiseki, Atsuto; Funayama, Kosuke; Egawa, Fuyuki; Okada, Shino; Adachi, Hiroaki; Terada, Masahiro

    2016-09-07

    A chiral Brønsted acid containing two different acidic sites, chiral carboxylic acid-monophosphoric acid 1a, was designed to be a new and effective concept in catalytic asymmetric hetero-Diels-Alder reactions of azopyridinecarboxylate with amidodienes. The multipoint hydrogen-bonding interactions among the carboxylic acid, monophosphoric acid, azopyridinecarboxylate, and amidodiene achieved high catalytic and chiral efficiency, producing substituted 1,2,3,6-tetrahydropyridazines with excellent stereocontrol in a single step. This constitutes the first example of regio-, diastereo-, and enantioselective azo-hetero-Diels-Alder reactions by chiral Brønsted acid catalysis.

  19. Lipase catalyzed epoxidation of fatty acid methyl esters derived from unsaturated vegetable oils in absence of carboxylic acid.

    Science.gov (United States)

    Sustaita-Rodríguez, Alejandro; Ramos-Sánchez, Víctor H; Camacho-Dávila, Alejandro A; Zaragoza-Galán, Gerardo; Espinoza-Hicks, José C; Chávez-Flores, David

    2018-04-11

    Nowadays the industrial chemistry reactions rely on green technologies. Enzymes as lipases are increasing its use in diverse chemical processes. Epoxidized fatty acid methyl esters obtained from transesterification of vegetable oils have recently found applications as polymer plasticizer, agrochemical, cosmetics, pharmaceuticals and food additives. In this research article, grapeseed, avocado and olive oils naturally containing high percents of mono and poly unsaturations were used as starting materials for the production of unsaturated fatty acid methyl esters. The effect of lauric acid as an active oxygen carrier was studied on epoxidation reactions where unsaturated fatty acid methyl esters were converted to epoxy fatty acid methyl esters using immobilized Candida antarctica Lipase type B as catalyst and hydrogen peroxide as oxygen donor at mild temperature and pressure conditions. After this study it was confirmed by 1 H NMR, 13 C NMR and GC-MS that the addition of lauric acid to the enzymatic reaction is unnecessary to transform the alkenes in to epoxides. It was found that quantitative conversions were possible in despite of a carboxylic acid absence.

  20. Copper Complexes of Nicotinic-Aromatic Carboxylic Acids as Superoxide Dismutase Mimetics

    Directory of Open Access Journals (Sweden)

    Virapong Prachayasittikul

    2008-12-01

    Full Text Available Nicotinic acid (also known as vitamin B3 is a dietary element essential for physiological and antihyperlipidemic functions. This study reports the synthesis of novel mixed ligand complexes of copper with nicotinic and other select carboxylic acids (phthalic, salicylic and anthranilic acids. The tested copper complexes exhibited superoxide dismutase (SOD mimetic activity and antimicrobial activity against Bacillus subtilis ATCC 6633, with a minimum inhibition concentration of 256 μg/mL. Copper complex of nicotinic-phthalic acids (CuNA/Ph was the most potent with a SOD mimetic activity of IC50 34.42 μM. The SOD activities were observed to correlate well with the theoretical parameters as calculated using density functional theory (DFT at the B3LYP/LANL2DZ level of theory. Interestingly, the SOD activity of the copper complex CuNA/Ph was positively correlated with the electron affinity (EA value. The two quantum chemical parameters, highest occupied molecular orbital (HOMO and lowest unoccupied molecular orbital (LUMO, were shown to be appropriate for understanding the mechanism of the metal complexes as their calculated energies show good correlation with the SOD activity. Moreover, copper complex with the highest SOD activity were shown to possess the lowest HOMO energy. These findings demonstrate a great potential for the development of value-added metallovitamin-based therapeutics.

  1. Liquid chromatographic determination of urinary 2-thiothiazolidine-4-carboxylic acid, a biomarker of carbon disulphide exposure.

    Science.gov (United States)

    Lee, B L; Yang, X F; New, A L; Ong, C N

    1995-06-23

    An effective gradient high-performance liquid chromatographic method for baseline separation of urinary 2-thiothiazolidine-4-carboxylic acid (TTCA), with photodiode array detection at 271 nm was described. o-Methylhippuric acid was used as an internal standard (I.S.). A 1-ml urine sample was saturated with 300 mg of sodium sulphate, acidified with 100 microliters of 6 M hydrochloric acid, extracted twice with 2 ml of diethyl ether, and after evaporation, the residue was taken up in 1 ml of 0.1% (v/v) phosphoric acid. The two mobile phases used for gradient elution were: (A) 10 mM ammonium dihydrogenphosphate (pH 3.5) and (B) same concentration of buffer but containing 20% (v/v) of methanol (pH 4.8). The flow-rate was set at 1.0 ml/min. TTCA and I.S. were detected at 2.2 and 9.1 min, respectively. The method was validated with urine samples collected from normal subjects and workers occupationally exposed to carbon disulphide. The present method enables the detection of urinary TTCA at a concentration of 0.025 mg/l. Analytical recovery and reproducibility generally exceeded 90%. The proposed method is considered more sensitive, specific and reliable than other existing methods.

  2. (Liquid + liquid) equilibria measurements for ternary systems (sulfolane + a carboxylic acid + n-heptane) at T = 303.15 K and at 0.1 MPa

    International Nuclear Information System (INIS)

    Cele, N.P.; Bahadur, I.; Redhi, G.G.; Ebenso, E.E.

    2016-01-01

    Highlights: • The (liquid + liquid) equilibrium for (sulfolane + a carboxylic acid + heptane) was measured. • Selectivity values for solvent separation efficiency were calculated. • Separation of carboxylic acids from heptane is feasible by extraction. • Three parameter equations have been fitted to the binodal curve data. • The NRTL and UNIQUAC models were used to correlate the experimental data. - Abstract: In the present work, new (liquid + liquid) equilibrium (LLE) values are reported for ternary systems {sulfolane(1) + acetic acid, or propanoic acid, or butanoic acid, or 2-methylpropanoic acid, or pentanoic acid, or 3-methylbutanoic acid (2) + n-heptane (3)} at T = 303.15 K and at p = 0.1 MPa. The mutual solubility of carboxylic acid in sulfolane is dependent on the length and structure of the alkyl chain of the carboxylic acid; it progressively increases with an increase in the alkyl chain of the carboxylic acid. The single phase homogenous region increases as the alkyl chain of the carboxylic acid increases. The n-heptane is most soluble in the carboxylic acid mixtures with long alkyl chain, that is, (3-methylbutanoic acid + sulfolane) and (pentanoic acid + sulfolane) systems and least soluble in the carboxylic acid with short alkyl chain (acetic acid + sulfolane) system. Carboxylic acid together with many other oxygenates and hydrocarbons are produced by SASOL Company in South Africa using the Fischer–Tropsch process. The details about this process are given in introduction section. The NRTL and UNIQUAC models were used to correlate the experimental tie-lines and to calculate the phase compositions of the ternary systems. It was found that the NRTL model fits the experimental values significantly better than the UNIQUAC model.

  3. What is the enthalpy of formation of pyrazine-2-carboxylic acid?

    International Nuclear Information System (INIS)

    Miranda, Margarida S.; Duarte, Darío J.R.; Liebman, Joel F.

    2016-01-01

    There are two contemporary conflicting, indeed, incompatible determinations of measurements of the enthalpies of combustion and of formation of pyrazine-2-carboxylic acid in the literature, (−2268.0 ± 0.9 and −271.2 ± 1.1 kJ · mol −1 ) and (−2211.4 ± 0.9 and −327.8 ± 1.1 kJ · mol −1 ). The current paper discusses these two sets of values and from the use of a measurement of the enthalpy of sublimation, a newly evaluated enthalpy of formation of pyrazine itself, and of the quantum chemical calculations at the G3(MP2)//B3LYP level, the former results are accepted and the derived gas phase enthalpy of formation, −(167.6 ± 3.1) kJ · mol −1 , suggested.

  4. Polymorphism in Self-Assembled Structures of 9-Anthracene Carboxylic Acid on Ag(111

    Directory of Open Access Journals (Sweden)

    Bo Xu

    2012-06-01

    Full Text Available Surface self-assembly process of 9-anthracene carboxylic acid (AnCA on Ag(111 was investigated using STM. Depending on the molecular surface density, four spontaneously formed and one annealed AnCA ordered phases were observed, namely a straight belt phase, a zigzag double-belt phase, two simpler dimer phases, and a kagome phase. The two high-density belt phases possess large unit cells on the scale length of 10 nm, which are seldom observed in molecular self-assembled structures. This structural diversity stems from a complicated competition of different interactions of AnCA molecules on metal surface, including intermolecular and molecular-substrate interactions, as well as the steric demand from high molecular surface density.

  5. Nuclear magnetic resonance titration studies of simple host-guest amine-carboxylic acid systems

    International Nuclear Information System (INIS)

    Mahinay, Myrna S.; Lindoy, Leonard F.

    1999-01-01

    Adduct formation for the open-chain 1,2-diaminoethane and its N-methyl derivatives [N,N-dimethyl-ethylenediamine (N,N-DMEN),N,N'-dimethylethylenediamine (N,N'-DMEN);N,N,N',N'-tetramethyl-ethylenediamine (N,N,N',N'-TMEN)]; 1,4-diaminobutane; diethylenetriamine (DIEN); triethylenetramine (TRIEN); and the carboxylic acid systems in polar CD 3 OH and nonpolar CDCl 3 solvents were elucidated by nmr titration. The stoichiometries of the adducts were found to correspond to the number of nitrogen present in the amine species with the exception of ligand incorporating N-donors of low basicity; that is, whose log K values for the protonated species in water were less than approximately 6 to 7.(Author)

  6. Omega-3 carboxylic acids (Epanova): a review of its use in patients with severe hypertriglyceridemia.

    Science.gov (United States)

    Blair, Hannah A; Dhillon, Sohita

    2014-10-01

    Omega-3 carboxylic acids (Epanova) [OM3-CA] is the first free fatty acid form of long-chain marine omega-3 fatty acids (eicosapentaenoic acid and docosahexaenoic acid being the most abundant) to be approved by the US FDA as an adjunct to diet to lower triglyceride levels in patients with severe hypertriglyceridemia (≥ 500 mg/dL). Oral OM3-CA has greater bioavailability than ethyl ester forms of omega-3 and, unlike omega-3 acid ethyl esters, does not require co-ingestion of a high-fat meal, as it does not need pancreatic enzyme activity for absorption. In the 12-week EpanoVa fOr Lowering Very high triglyceridEs (EVOLVE) trial, OM3-CA 2 or 4 g/day significantly reduced serum triglyceride levels relative to placebo. Other lipid parameters, including non-high-density lipoprotein cholesterol (non-HDL-C), total cholesterol, and very low-density lipoprotein cholesterol (VLDL-C) levels, were also reduced significantly with OM3-CA relative to placebo. Low-density lipoprotein cholesterol levels were increased significantly with OM3-CA relative to placebo; however, these increases were not accompanied by increases in the circulating concentrations of non-HDL-C, VLDL-C, or apolipoprotein B. OM3-CA was generally well tolerated in this study, with most adverse events being of mild or moderate severity. Although additional comparative data are needed to position OM3-CA with respect to other formulations of omega-3 fatty acids, current evidence suggests that OM3-CA is a useful addition to the treatment options available for patients with severe hypertriglyceridemia.

  7. Photoacidic and Photobasic Behavior of Transition Metal Compounds with Carboxylic Acid Group(s)

    Energy Technology Data Exchange (ETDEWEB)

    O’Donnell, Ryan M. [Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States; Sampaio, Renato N. [Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States; Li, Guocan [Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States; Johansson, Patrik G. [Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States; Ward, Cassandra L. [Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States; Meyer, Gerald J. [Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States

    2016-03-10

    Excited state proton transfer studies of six Ru polypyridyl compounds with carboxylic acid/carboxylate group(s) revealed that some were photoacids and some were photobases. The compounds [RuII(btfmb)2(LL)]2+, [RuII(dtb)2(LL)]2+, and [RuII(bpy)2(LL)]2+, where bpy is 2,2'-bipyridine, btfmb is 4,4'-(CF3)2-bpy, and dtb is 4,4'-((CH3)3C)2-bpy, and LL is either dcb = 4,4'-(CO2H)2-bpy or mcb = 4-(CO2H),4'-(CO2Et)-2,2'-bpy, were synthesized and characterized. The compounds exhibited intense metal-to-ligand charge-transfer (MLCT) absorption bands in the visible region and room temperature photoluminescence (PL) with long τ > 100 ns excited state lifetimes. The mcb compounds had very similar ground state pKa’s of 2.31 ± 0.07, and their characterization enabled accurate determination of the two pKa values for the commonly utilized dcb ligand, pKa1 = 2.1 ± 0.1 and pKa2 = 3.0 ± 0.2. Compounds with the btfmb ligand were photoacidic, and the other compounds were photobasic. Transient absorption spectra indicated that btfmb compounds displayed a [RuIII(btfmb–)L2]2+* localized excited state and a [RuIII(dcb–)L2]2+* formulation for all the other excited states. Time dependent PL spectral shifts provided the first kinetic data for excited state proton transfer in a transition metal compound. PL titrations, thermochemical cycles, and kinetic analysis (for the mcb compounds) provided self-consistent pKa* values. The ability to make a single ionizable group photobasic or photoacidic through ligand design was unprecedented and was understood based on the orientation of the lowest-lying MLCT excited state dipole relative to the ligand that contained the carboxylic acid group(s).

  8. A combined experimental and computational thermodynamic study of fluorene-9-methanol and fluorene-9-carboxylic acid

    International Nuclear Information System (INIS)

    Oliveira, Juliana A.S.A.; Calvinho, Maria M.; Notario, R.; Monte, Manuel J.S.; Ribeiro da Silva, Maria D.M.C.

    2013-01-01

    Highlights: • A thermodynamic study of two fluorene derivatives is presented. • Vapour pressures and energies of combustion were measured. • Enthalpy, entropy and Gibbs energy of sublimation were derived. • Enthalpy and Gibbs energy of formation in crystal and gas phases were calculated. • Gas phase enthalpy of formation was also estimated by quantum chemical calculations. -- Abstract: This work reports an experimental and computational thermodynamic study performed on two 9-fluorene derivatives: fluorene-9-methanol and fluorene-9-carboxylic acid. The standard (p o = 0.1 MPa) molar enthalpies of formation in the crystalline phase of these compounds were derived from the standard molar energies of combustion, in oxygen, at T = 298.15 K, measured by static bomb combustion calorimetry. A static method, based on a capacitance diaphragm gauge, and a Knudsen effusion method were used to perform the vapour pressure study of the referred compounds, yielding accurate determination of the standard molar enthalpies and entropies of sublimation and vaporisation. For fluorene-9-carboxylic acid, the enthalpy of sublimation was also determined using Calvet microcalorimetry. The enthalpy of fusion of both compounds was derived indirectly from vapour pressure results and directly from DSC experiments. Combining the thermodynamic parameters of the compounds studied, the standard Gibbs energy of formation in crystalline and gaseous phases were derived as well as the standard molar enthalpy of formation in the gaseous phase. A theoretical study at the G3 and G4 levels has been carried out, and the calculated enthalpies of formation have been compared with the experimental values

  9. Charge-transfer excited state in pyrene-1-carboxylic acids adsorbed on titanium dioxide nanoparticles

    Science.gov (United States)

    Krawczyk, S.; Nawrocka, A.; Zdyb, A.

    2018-06-01

    The electronic structure of excited photosensitizer adsorbed at the surface of a solid is the key factor in the electron transfer processes that underlie the efficiency of dye-sensitized solar cells and photocatalysts. In this work, Stark effect (electroabsorption) spectroscopy has been used to measure the polarizability and dipole moment changes in electronic transitions of pyrene-1-carboxylic (PCA), -acetic (PAA) and -butyric (PBA) acids in ethanol, both free and adsorbed on colloidal TiO2, in glassy ethanol at low temperature. The lack of appreciable increase of dipole moment in the excited state of free and adsorbed PAA and PBA points that two or more single bonds completely prevent the expansion of π-electrons from the aromatic ring towards the carboxylic group, thus excluding the possibility of direct electron injection into TiO2. In free PCA, the pyrene's forbidden S0 → S1 transition has increased intensity, exhibits a long progression in 1400 cm-1 Ag mode and is associated with |Δμ| of 2 D. Adsorption of PCA on TiO2 causes a broadening and red shift of the S0 → S1 absorption band and an increase in dipole moment change on electronic excitation to |Δμ| = 6.5 D. This value increased further to about 15 D when the content of acetic acid in the colloid was changed from 0.2% to 2%, and this effect is ascribed to the surface electric field. The large increase of |Δμ| points that the electric field effect can not only change the energetics of electron transfer from the excited sensitizer into the solid, but can also shift the molecular electronic density, thus directly influencing the electronic coupling factor relevant for electron transfer at the molecule-solid interface.

  10. Imidazolinium and amidinium salts as Lewis acid organocatalysts

    Directory of Open Access Journals (Sweden)

    Oksana Sereda

    2012-10-01

    Full Text Available The application of imidazolinium and amidinium salts as soft Lewis acid organocatalysts is described. These salts were suitable catalysts for the activation of unsaturated thioesters in a Diels–Alder reaction and in the ring opening of thiiranes and epoxides. The products were isolated in good yields. The mild catalysts did not cause desulfurization of the products containing a thiol or thiocarbonyl group.

  11. Inorganic salts interact with oxalic acid in submicron particles to form material with low hygroscopicity and volatility

    Science.gov (United States)

    Drozd, G.; Woo, J.; Häkkinen, S. A. K.; Nenes, A.; McNeill, V. F.

    2014-05-01

    Volatility and hygroscopicity are two key properties of organic aerosol components, and both are strongly related to chemical identity. While the hygroscopicities of pure salts, di-carboxylic acids (DCA), and DCA salts are known, the hygroscopicity of internal mixtures of these components, as they are typically found in the atmosphere, has not been fully characterized. Here we show that inorganic-organic component interactions typically not considered in atmospheric models can lead to very strongly bound metal-organic complexes and greatly affect aerosol volatility and hygroscopicity; in particular, the bi-dentate binding of DCA to soluble inorganic ions. We have studied the volatility of pure, dry organic salt particles and the hygroscopicity of internal mixtures of oxalic acid (OxA, the dominant DCA in the atmosphere) and a number of salts, both mono- and di-valent. The formation of very low volatility organic salts was confirmed, with minimal evaporation of oxalate salt particles below 75 °C. Dramatic increases in the cloud condensation nuclei (CCN) activation diameter for particles with di-valent salts (e.g., CaCl2) and relatively small particle volume fractions of OxA indicate that standard volume additivity rules for hygroscopicity do not apply. Thus small organic compounds with high O : C ratios are capable of forming low-volatility and very low hygroscopicity particles. Given current knowledge of the formation mechanisms of OxA and M-Ox salts, surface enrichment of insoluble M-Ox salts is expected. The resulting formation of an insoluble coating of metal-oxalate salts can explain low-particle hygroscopicities. The formation of particles with a hard coating could offer an alternative explanation for observations of glass-like particles without the need for a phase transition.

  12. Recovery of carboxylic acids produced during dark fermentation of food waste by adsorption on Amberlite IRA-67 and activated carbon.

    Science.gov (United States)

    Yousuf, Ahasa; Bonk, Fabian; Bastidas-Oyanedel, Juan-Rodrigo; Schmidt, Jens Ejbye

    2016-10-01

    Amberlite IRA-67 and activated carbon were tested as promising candidates for carboxylic acid recovery by adsorption. Dark fermentation was performed without pH control and without addition of external inoculum at 37°C in batch mode. Lactic, acetic and butyric acids, were obtained, after 7days of fermentation. The maximum acid removal, 74%, from the Amberlite IRA-67 and 63% from activated carbon was obtained from clarified fermentation broth using 200gadsorbent/Lbroth at pH 3.3. The pH has significant effect and pH below the carboxylic acids pKa showed to be beneficial for both the adsorbents. The un-controlled pH fermentation creates acidic environment, aiding in adsorption by eliminating use of chemicals for efficient removal. This study proposes simple and easy valorization of waste to valuable chemicals. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Clozapine-carboxylic acid plasticized co-amorphous dispersions: Preparation, characterization and solution stability evaluation

    Directory of Open Access Journals (Sweden)

    Ali Ahmed Mahmoud Abdelhaleem

    2015-06-01

    Full Text Available This study addressed the possibility of forming of co-amorphous systems between clozapine (CZ and various carboxylic acid plasticizers (CAPs. The aim was to improve the solubility and oral bioavailability of clozapine. Co-amorphous dispersions were prepared using modified solvent evaporation methodology at drug/plasticizer stoichiometric ratios of 1:1, 1:1.5 and 1:2. Solid state characterization was performed using differential scanning calorimetry, X-ray diffraction and infra red spectroscopy. Highly soluble homogeneous co-amorphous dispersions were formed between clozapine and CAPs via hydrogen bonding. The co-amorphous dispersions formed with tartaric acid (1:2 showed the highest dissolution percentage (> 95 % in 20 minutes compared to pure crystalline CZ (56 %. Highly stable solutions were obtained from co-amorphous CZ-citric and CZ-tartaric acid at 1:1.5 molar ratio. The prepared dispersions suggest the possibility of peroral or sublingual administration of highly soluble clozapine at a reduced dose with the great chance to bypass the first pass metabolism.

  14. Equilibrium studies of ternary systems containing some selected transition metal ions, triazoles and aromatic carboxylic acids

    Energy Technology Data Exchange (ETDEWEB)

    Khalil, Mohamed Magdy; Radalla, Abd-Elatty; Qasem, Fatma; Khaled, Rehab [Beni-Suef University, Beni-Suef (Egypt)

    2014-01-15

    Solution equilibria of the binary and ternary complex systems of the divalent transition metal ions Cu{sup 2+}, Ni{sup 2+}, Zn{sup 2+}, and Co{sup 2+} with 1,2,4-triazole (TRZ), 3-mercapto-1,2,4-triazole (TRZSH), and 3-amino-1,2,4-triazole (TRZAM) and aromatic carboxylic acids (phthalic, anthranilic, salicylic, and 5-sulfosalicylic acid) have been studied pH-metrically at (25.0±0.1) .deg. C, and a constant ionic strength I=1x10{sup -1} mol L{sup -1} NaNO{sub 3} in an aqueous medium. The potentiometric titration curves show that binary and ternary complexes of these ligands are formed in solution. The stability constants of the different binary and ternary complexes formed were calculated on the basis of computer analysis of the titration data. The relative stability of the different ternary complex species is expressed in terms of Δ log K values, log X and R. S.% parameters. The effect of temperature of the medium on both the proton-ligand equilibria for TRZAM and phthalic acid and their metal-ligand equilibria with Cu{sup 2+}, Ni{sup 2+}, and Co{sup 2+} has been studied along with the corresponding thermodynamic parameters. The complexation behavior of ternary complexes is ascertained using conductivity measurements. In addition, the formation of ternary complexes in solution has been confirmed by using UV-visible spectrophotometry.

  15. Derivatization of carboxylic acids with 4-APEBA for detection by positive-ion LC-ESI-MS(/MS) applied for the analysis of prostanoids and NSAID in urine

    NARCIS (Netherlands)

    Kretschmer, A.; Giera, M.A.; Wijtmans, M.; de Vries, L.; Lingeman, H.; Irth, H.; Niessen, W.M.A.

    2011-01-01

    In order to develop a generic positive ionization ESI LC-MS method for a variety of interesting substance classes, a new derivatization strategy for carboxylic acids was developed. The carboxylic acid group is labeled with the bromine containing 4-APEBA reagent based on carbodiimide chemistry. The

  16. LIQUID-CHROMATOGRAPHIC ANALYSIS OF CARBOXYLIC-ACIDS USING N-(4-AMINOBUTYL)-N-ETHYLISOLUMINOL AS CHEMILUMINESCENT LABEL - DETERMINATION OF IBUPROFEN IN SALIVA

    NARCIS (Netherlands)

    STEIJGER, OM; LINGEMAN, H; BRINKMAN, UAT; HOLTHUIS, JJM; SMILDE, AK; DOORNBOS, DA

    1993-01-01

    N-(4-Aminobutyl)-N-ethylisoluminol was used for labelling of carboxylic acids. The derivatization reaction was carried out with 1-hydroxybenzotriazole as pre-activator of the carboxylic acid function and N-ethyl-N'-(3-dimethylaminopropyl)carbodiimide as the coupling reagent. Optimum conditions for

  17. Liquid chromatographic analysis of carboxylic acids using N-(4-aminobutyl)-N-ethylisoluminol as chemiluminescent label: determination of ibuprofen in saliva

    NARCIS (Netherlands)

    Steijger, O. M.; Lingeman, H.; Brinkman, U. A.; Holthuis, J. J.; Smilde, A. K.; Doornbos, D. A.

    1993-01-01

    N-(4-Aminobutyl)-N-ethylisoluminol was used for labelling of carboxylic acids. The derivatization reaction was carried out with 1-hydroxybenzotriazole as pre-activator of the carboxylic acid function and N-ethyl-N'-(3-dimethylaminopropyl)carbodiimide as the coupling reagent. Optimum conditions for

  18. Ambazone-lipoic acid salt: Structural and thermal characterization

    Energy Technology Data Exchange (ETDEWEB)

    Kacso, Irina [National Institute for Research and Development of Isotopic and Molecular Technologies, 65-103 Donath street, 400293 Cluj-Napoca (Romania); Racz, Csaba-Pal; Santa, Szabolcs [Babes-Bolyai' University, Faculty of Chemistry, 11 Arany Janos street, Cluj-Napoca (Romania); Rus, Lucia [' Iuliu Hatieganu' University of Medicine and Pharmacy, Faculty of Pharmacy, 6 Louis Pasteur street, 400349 Cluj-Napoca (Romania); Dadarlat, Dorin; Borodi, Gheorghe [National Institute for Research and Development of Isotopic and Molecular Technologies, 65-103 Donath street, 400293 Cluj-Napoca (Romania); Bratu, Ioan, E-mail: ibratu@gmail.com [National Institute for Research and Development of Isotopic and Molecular Technologies, 65-103 Donath street, 400293 Cluj-Napoca (Romania)

    2012-12-20

    Highlights: Black-Right-Pointing-Pointer Salt of Ambazone with lipoic acid obtained by solvent-drop grinding. Black-Right-Pointing-Pointer Ambazone lipoate salt crystallizes in monoclinic system. Black-Right-Pointing-Pointer FTIR data suggest the deprotonation of the lipoic acid. Black-Right-Pointing-Pointer Thermal behaviour different of ambazone salt as compared to the starting compounds. - Abstract: A suitable method for increasing the solubility, dissolution rate and consequently the bioavailability of poor soluble acidic or basic drugs is their salt formation. The aim of this study is to investigate the structural and thermal properties of the compound obtained by solvent drop grinding (SDG) method at room temperature, starting from the 1:1 molar ratios of ambazone (AMB) and {alpha}-lipoic acid (LA). The structural characterization was performed with X-ray powder diffraction (XRPD) and infrared spectroscopy (FTIR). The thermal behaviour of the obtained compound (AMB{center_dot}LA) was investigated by differential scanning calorimetry (DSC) and thermogravimetry (TG). The photopyroelectric calorimetry, in front detection configuration (FPPE), was applied to measure and compare the room temperature values of one dynamic thermal parameter (thermal effusivity) for starting and resulting compounds. Both structural and supporting calorimetric techniques pointed out a salt structure for AMB{center_dot}LA compound as compared to those of the starting materials.

  19. Phenazine-1-carboxylic acid influences biofilm development and turnover of rhizobacterial biomass in a soil moisture-dependent manner

    Science.gov (United States)

    Rhizobacterial biofilm development influences terrestrial carbon and nitrogen cycles with ramifications for crop and soil health. Phenazine-1-carboxylic acid (PCA) is a redox-active metabolite produced by rhizobacteria in dryland wheat fields of Washington and Oregon, USA. PCA promotes biofilm dev...

  20. Meso-ester and carboxylic acid substituted BODIPYs with far-red and near-infrared emission for bioimaging applications

    KAUST Repository

    Ni, Yong; Zeng, Lintao; Kang, Namyoung; Huang, Kuo-Wei; Wang, Liang; Zeng, Zebing; Chang, Young-Tae; Wu, Jishan

    2014-01-01

    -6) become partially soluble in water, and their absorptions and emissions are located in the far-red or near-infrared region. Three synthetic approaches are attempted to access the meso-carboxylic acid (COOH)-substituted BODIPYs 7 and 8 from the meso

  1. Characterisation and application of new carboxylic acid-functionalised ruthenium complexes as dye-sensitisers for solar cells

    DEFF Research Database (Denmark)

    Duprez, Virginie; Biancardo, Matteo; Krebs, Frederik C

    2007-01-01

    A series of ruthenium complexes with and without TiO2, anchoring carboxylic acid groups have been synthesised and characterised using nuclear magnetic resonance (NMR), UV-vis and luminescence. These complexes were adsorbed on thin films of the wide band-gap semiconductor anatase and were tested a...

  2. Phosphazene-promoted metal-free ring-opening polymerization of ethylene oxide initiated by carboxylic acid

    KAUST Repository

    Zhao, Junpeng; Pahovnik, David; Gnanou, Yves; Hadjichristidis, Nikolaos

    2014-01-01

    The effectiveness of carboxylic acid as initiator for the anionic ring-opening polymerization of ethylene oxide was investigated with a strong phosphazene base (t-BuP4) used as promoter. Kinetic study showed an induction period, i.e., transformation

  3. Erbium trifluoromethanesulfonate-catalyzed Friedel–Crafts acylation using aromatic carboxylic acids as acylating agents under monomode-microwave irradiation

    DEFF Research Database (Denmark)

    Tran, Phuong Hoang; Hansen, Poul Erik; Nguyen, Hai Truong

    2015-01-01

    Erbium trifluoromethanesulfonate is found to be a good catalyst for the Friedel–Crafts acylation of arenes containing electron-donating substituents using aromatic carboxylic acids as the acylating agents under microwave irradiation. An effective, rapid and waste-free method allows the preparation...... of a wide range of aryl ketones in good yields and in short reaction times with minimum amounts of waste...

  4. Tropanol esters of metallocene carboxylic acids. Syntheses, labelling with 103Ru and sup(103m)Rh and organ distribution

    International Nuclear Information System (INIS)

    Wenzel, M.; Wu, Y.

    1988-01-01

    The tropanol esters of the carboxylic acids of ferrocene, 103 Ru-ruthenocene and sup(103m)Rh-rhodocinium were synthezised. The organ distribution of the 103 Ru or sup(103m)Rh labelled tropanol-esters were investigated. Only the 103 Ru labelled ester showed a high heart/blood ratio. (author)

  5. Investigation of supramolecular synthons and structural characterisation of aminopyridine-carboxylic acid derivatives.

    Science.gov (United States)

    Hemamalini, Madhukar; Loh, Wan-Sin; Quah, Ching Kheng; Fun, Hoong-Kun

    2014-01-01

    Co-crystal is a structurally homogeneous crystalline material that contains two or more neutral building blocks that are present in definite stoichiometric amounts. The main advantage of co-crystals is their ability to generate a variety of solid forms of a drug that have distinct physicochemical properties from the solid co-crystal components. In the present investigation, five co-crystals containing 2-amino-6-chloropyridine (AMPY) moiety were synthesized and characterized. The crystal structure of 2-amino-6-chloropyridine (AMPY) (I), and the robustness of pyridine-acid supramolecular synthon were discussed in four stoichiometry co-crystals of AMPY…BA (II), AMPY…2ABA (III), AMPY…3CLBA (IV) and AMPY…4NBA (V). The abbreviated designations used are benzoic acid (BA), 2-aminobenzoic acid (2ABA), 3-chlorobenzoic acid (3CLBA) and 4-nitrobenzoic acid (4NBA). All the crystalline materials have been characterized by (1)HNMR, (13)CNMR, IR, photoluminescence, TEM analysis and X-ray diffraction. The supramolecular assembly of each co-crystal is analyzed and discussed. Extensive N---H · · · N/N---H · · · O/O---H · · · N hydrogen bonds are found in (I-V), featuring different supramolecular synthons. In the crystal structure, for compound (I), the 2-amino-6-chloropyridine molecules are linked together into centrosymmetric dimers by hydrogen bonds to form homosynthon, whereas for compounds (II-V), the carboxylic group of the respective acids (benzoic acid, 2-aminobenzoic acid, 3-chlorobenzoic acid and 4-nitrobenzoic acid) interacts with pyridine molecule in a linear fashion through a pair of N---H · · · O and O---H · · · N hydrogen bonds, generating cyclic hydrogen-bonded motifs with the graph-set notation [Formula: see text] , to form heterosynthon. In compound (II), another intermolecular N---H · · · O hydrogen bonds further link these heterosynthons into zig-zag chains. Whereas in compounds (IV) and (V

  6. Enhancing Cooperativity in Bifunctional Acid–Pd Catalysts with Carboxylic Acid-Functionalized Organic Monolayers

    Energy Technology Data Exchange (ETDEWEB)

    Coan, Patrick D. [Department of Chemical and Biological Engineering, University of Colorado—Boulder, Boulder, Colorado 80309, United States; Ellis, Lucas D. [Department of Chemical and Biological Engineering, University of Colorado—Boulder, Boulder, Colorado 80309, United States; Griffin, Michael B. [National Bioenergy Center, National Renewable Energy Laboratory, Golden, Colorado 80401, United States; Schwartz, Daniel K. [Department of Chemical and Biological Engineering, University of Colorado—Boulder, Boulder, Colorado 80309, United States; Medlin, J. Will [Department of Chemical and Biological Engineering, University of Colorado—Boulder, Boulder, Colorado 80309, United States

    2018-03-01

    Cooperative catalysts containing a combination of noble metal hydrogenation sites and Bronsted acid sites are critical for many reactions, including the deoxygenation (DO) of biomass-derived oxygenates in the upgrading of pyrolysis oil. One route toward the design of cooperative catalysts is to tether two different catalytically active functions so that they are in close proximity while avoiding undesirable interactions that can block active sites. Here, we deposited carboxylic acid (CA)-functionalized organophosphonate monolayers onto Al2O3-supported Pd nanoparticle catalysts to prepare bifunctional catalysts containing both Bronsted acid and metal sites. Modification with phosphonic acids (PAs) improved activity and selectivity for gas-phase DO reactions, but the degree of improvement was highly sensitive to both the presence and positioning of the CA group, suggesting a significant contribution from both the PA and CA sites. Short spacer lengths of 1-2 methylene groups between the phosphonate head and CA tail were found to yield the best DO rates and selectivities, whereas longer chains performed similarly to self-assembled monolayers having alkyl tails. Results from a combination of density functional theory and Fourier transform infrared spectroscopy suggested that the enhanced catalyst performance on the optimally positioned CAs was due to the generation of strong acid sites on the Al2O3 support adjacent to the metal. Furthermore, the high activity of these sites was found to result from a hydrogen-bonded cyclic structure involving cooperativity between the phosphonate head group and CA tail function. More broadly, these results indicate that functional groups tethered to supports via organic ligands can influence catalytic chemistry on metal nanoparticles.

  7. Sulfonated reduced graphene oxide as a highly efficient catalyst for direct amidation of carboxylic acids with amines using ultrasonic irradiation.

    Science.gov (United States)

    Mirza-Aghayan, Maryam; Tavana, Mahdieh Molaee; Boukherroub, Rabah

    2016-03-01

    Sulfonated reduced graphene oxide nanosheets (rGO-SO3H) were prepared by grafting sulfonic acid-containing aryl radicals onto chemically reduced graphene oxide (rGO) under sonochemical conditions. rGO-SO3H catalyst was characterized by Fourier-transform infrared (FT-IR) spectroscopy, Raman spectroscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and X-ray photoelectron spectroscopy (XPS). rGO-SO3H catalyst was successfully applied as a reusable solid acid catalyst for the direct amidation of carboxylic acids with amines into the corresponding amides under ultrasonic irradiation. The direct sonochemical amidation of carboxylic acid takes place under mild conditions affording in good to high yields (56-95%) the corresponding amides in short reaction times. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. 1-Aminocyclopropane-1-carboxylic acid and abscisic acid during the germination of sugar beet (Beta vulgaris L.): a comparative study of fruits and seeds

    Czech Academy of Sciences Publication Activity Database

    Hermann, K.; Meinhard, J.; Dobrev, Petre; Linkies, A.; Pešek, Bedřich; Heß, B.; Macháčková, Ivana; Fischer, U.; Leubner-Metzger, G.

    2007-01-01

    Roč. 58, č. 11 (2007), s. 3047-3060 ISSN 0022-0957 Institutional research plan: CEZ:AV0Z50380511 Keywords : abscisic acid (ABA) * ABA 8'-hydroxylase (CYP707A) * 1-aminocyclopropane-1-carboxylic acid ( ACC ) Subject RIV: EF - Botanics Impact factor: 3.917, year: 2007

  9. Synergistic enhancement of ethylene production and germination with kinetin and 1-aminocyclopropane-1-carboxylic Acid in lettuce seeds exposed to salinity stress.

    Science.gov (United States)

    Khan, A A; Huang, X L

    1988-08-01

    Relief of salt (0.1 molar NaCl) stress on germination of lettuce (Lactuca sativa L., cv Mesa 659) seeds occurred with applications of 0.05 millimolar kinetin (KIN) and 1 to 10 millimolar 1-aminocyclopropane 1-carboxylic acid (ACC). Treatment with KIN enhanced the pregermination ethylene production under saline condition. A synergistic or an additive enhancement of pregermination ethylene production and germination occurred under saline condition in the presence of KIN and a saturating dose (10 millimolar) of ACC. No KIN-ACC synergism was noted in ethylene production or germination under nonsaline condition. Addition of 1 millimolar aminoethoxyvinylglycine (AVG) inhibited the KIN-enhanced pregermination ethylene production (85 to 89%) and germination (58%) under saline condition but not the synergistic effect of KIN + ACC on ethylene production. Under nonsaline condition, AVG had no effect on germination even though ethylene production was strongly inhibited. Alleviation of salt stress by KIN was inhibited in a competitive manner by 2,5-norbornadiene (NBD) (0.02-0.2 milliliter per liter), and the addition of ACC and/or ethylene reduced this inhibition. An increase in the pregermination ethylene production and germination occurred also by cotylenin E (CN) under saline condition. However, neither AVG (1 millimolar) nor NBD (0.02 to 0.2 milliliter per liter) prevented the relief of salt stress by CN. Thus, KIN may alleviate salt stress on germination by promoting both ACC production and its conversion to ethylene. Rapid utilization of ACC may be the basis for the synergistic or the additive effect of KIN plus ACC. The need for ethylene production and action for the relief of salt stress is circumvented by a treatment with CN.

  10. In vitro assessment of potential intestinal absorption of some phenolic families and carboxylic acids from commercial instant coffee samples.

    Science.gov (United States)

    López-Froilán, R; Ramírez-Moreno, E; Podio, N S; Pérez-Rodríguez, M L; Cámara, M; Baroni, M V; Wunderlin, D A; Sánchez-Mata, M C

    2016-06-15

    Coffee is one of the most consumed beverages in the world, being a source of bioactive compounds as well as flavors. Hydroxycinnamic acids, flavonols, and carboxylic acids have been studied in the samples of instant coffee commercialized in Spain. The studies about contents of food components should be complemented with either in vitro or in vivo bioaccessibility studies to know the amount of food components effectively available for functions in the human body. In this sense, a widely used in vitro model has been applied to assess the potential intestinal absorption of phenolic compounds and organic acids. The contents of hydroxycinnamic acids and flavonols were higher in instant regular coffee samples than in the decaffeinated ones. Bioaccessible phenolic compounds in most analyzed samples account for 20-25% of hydroxycinnamic acids and 17-26% of flavonols. This could mean that a great part of them can remain in the gut, acting as potential in situ antioxidants. Quinic, acetic, pyroglutamic, citric and fumaric acids were identified in commercial instant coffee samples. Succinic acid was found in the coffee blend containing chicory. All carboxylic acids showed a very high bioaccessibility. Particularly, acetic acid and quinic acid were found in higher contents in the samples treated with the in vitro simulation of gastrointestinal processes, compared to the original ones, which can be explained by their cleavage from chlorogenic acid during digestion. This is considered as a positive effect, since quinic acid is considered as an antioxidant inducer.

  11. Metal-Catalyzed Intra- and Intermolecular Addition of Carboxylic Acids to Alkynes in Aqueous Media: A Review

    Directory of Open Access Journals (Sweden)

    Javier Francos

    2017-11-01

    Full Text Available The metal-catalyzed addition of carboxylic acids to alkynes is a very effective tool for the synthesis of carboxylate-functionalized olefinic compounds in an atom-economical manner. Thus, a large variety of synthetically useful lactones and enol-esters can be accessed through the intra- or intermolecular versions of this process. In order to reduce the environmental impact of these reactions, considerable efforts have been devoted in recent years to the development of catalytic systems able to operate in aqueous media, which represent a real challenge taking into account the tendency of alkynes to undergo hydration in the presence of transition metals. Despite this, different Pd, Pt, Au, Cu and Ru catalysts capable of promoting the intra- and intermolecular addition of carboxylic acids to alkynes in a selective manner in aqueous environments have appeared in the literature. In this review article, an overview of this chemistry is provided. The synthesis of β-oxo esters by catalytic addition of carboxylic acids to terminal propargylic alcohols in water is also discussed.

  12. Oxidation of ethoxylated fatty alcohols to alkylpolyglycol carboxylic acids using noble metals as catalysts

    Directory of Open Access Journals (Sweden)

    Sagredos, Angelos

    2009-09-01

    Full Text Available The conversion of ethoxylated fatty alcohols to the corresponding carboxylic acids through dehydrogenation/ oxidation using noble-metal catalysts has been studied. Ethoxylated primary aliphatic alcohols, ethoxylated random secondary aliphatic alcohols and ethoxylated alkylphenols have been converted to the corresponding acids in the presence of a base. The noble metal catalysts Palladium and Platinum were used without significant degradation of the ethoxyl chain in yields that exceeded 90%. On the other hand, the catalysts Rhodium and Ruthenium gave yields of about 80% and 60% respectively.La conversión de alcoholes grasos etoxilados a los correspondientes ácidos carboxílicos por deshidrogenación/ oxidación con metales nobles como catalizador ha sido estudiada. Alcoholes primarios alifáticos etoxilados, alcoholes alifáticos secundarios etoxilados al azar y alquilfenoles etoxilados han sido convertidos a los correspondientes ácidos en presencia de base. Los catalizadores paladio y platino fueron usados sin degradación significativa de las cadenas etoxiladas con un rendimiento que excedió del 90%. Por otra parte catalizadores de rodio y rutenio produjeron rendimientos del 80 y 60%, respectivamente.

  13. A Single Enzyme Transforms a Carboxylic Acid into a Nitrile through an Amide Intermediate.

    Science.gov (United States)

    Nelp, Micah T; Bandarian, Vahe

    2015-09-01

    The biosynthesis of nitriles is known to occur through specialized pathways involving multiple enzymes; however, in bacterial and archeal biosynthesis of 7-deazapurines, a single enzyme, ToyM, catalyzes the conversion of the carboxylic acid containing 7-carboxy-7-deazaguanine (CDG) into its corresponding nitrile, 7-cyano-7-deazaguanine (preQ0 ). The mechanism of this unusual direct transformation was shown to proceed via the adenylation of CDG, which activates it to form the newly discovered amide intermediate 7-amido-7-deazaguanine (ADG). This is subsequently dehydrated to form the nitrile in a process that consumes a second equivalent of ATP. The authentic amide intermediate is shown to be chemically and kinetically competent. The ability of ToyM to activate two different substrates, an acid and an amide, accounts for this unprecedented one-enzyme catalysis of nitrile synthesis, and the differential rates of these two half reactions suggest that this catalytic ability is derived from an amide synthetase that gained a new function. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Vaporization of protic ionic liquids derived from organic superbases and short carboxylic acids.

    Science.gov (United States)

    Ribeiro, Filipe M S; Lima, Carlos F R A C; Vaz, Inês C M; Rodrigues, Ana S M C; Sapei, Erlin; Melo, André; Silva, Artur M S; Santos, Luís M N B F

    2017-06-28

    This work presents a comprehensive evaluation of the phase behaviour and cohesive enthalpy of protic ionic liquids (PILs) composed of 1,5-diazabicyclo[4.3.0]non-5-ene (DBN) or 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) organic superbases with short-chain length (acetic, propionic and butyric) carboxylic acids. Glass transition temperatures, T g , and enthalpies of vaporization, ΔH vap , were measured for six [BH][A] (1 : 1) PILs (B = DBN, DBU; A = MeCOO, EtCOO, nPrCOO), revealing more significant changes upon increasing the number of -CH 2 - groups in the base than in the acid. The magnitude of ΔH vap evidences that liquid PILs have a high proportion of ions, although the results also indicate that in DBN PILs the concentration of neutral species is not negligible. In the gas phase, these PILs exist as a distribution of ion pairs and isolated neutral species, with speciation being dependent on the temperature and pressure conditions - at high temperatures and low pressures the separated neutral species dominate. The higher T g and ΔH vap of the DBU PILs are explained by the stronger basicity of DBU (as supported by NMR and computational calculations), which increases the extent of proton exchange and the ionic character of the corresponding PILs, resulting in stronger intermolecular interactions in condensed phases.

  15. Thermophysical properties of carboxylic and amino acid buffers at subzero temperatures: relevance to frozen state stabilization.

    Science.gov (United States)

    Sundaramurthi, Prakash; Suryanarayanan, Raj

    2011-06-02

    Macromolecules and other thermolabile biologicals are often buffered and stored in frozen or dried (freeze-dried) state. Crystallization of buffer components in frozen aqueous solutions and the consequent pH shifts were studied in carboxylic (succinic, malic, citric, tartaric acid) and amino acid (glycine, histidine) buffers. Aqueous buffer solutions were cooled from room temperature (RT) to -25 °C and the pH of the solution was measured as a function of temperature. The thermal behavior of frozen solutions was investigated by differential scanning calorimetry (DSC), and the crystallized phases were identified by X-ray diffractometry (XRD). Based on the solubility of the neutral species of each buffer system over a range of temperatures, it was possible to estimate its degree of supersaturation at the subambient temperature of interest. This enabled us to predict its crystallization propensity in frozen systems. The experimental and the predicted rank orderings were in excellent agreement. The malate buffer system was robust with no evidence of buffer component crystallization and hence negligible pH shift. In the citrate and tartrate systems, at initial pH pI. In the histidine buffer system, depending on the initial pH, either histidine or histidine HCl crystallized.

  16. 40 CFR 721.6200 - Fatty acid polyamine condensate, phosphoric acid ester salts.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Fatty acid polyamine condensate... New Uses for Specific Chemical Substances § 721.6200 Fatty acid polyamine condensate, phosphoric acid... substances identified as fatty acid polyamine condensate, phosphate ester salts (PMNs P-90-1984 and P-90-1985...

  17. Predicted Gas-Phase and Liquid-Phase Acidities of Carborane Carboxylic and Dicarboxylic Acids

    Czech Academy of Sciences Publication Activity Database

    Oliva-Enrich, J. M.; Humbel, S.; Santaballa, J.A.; Alkorta, I.; Notario, R.; Dávalos, J. Z.; Canle-L., M.; Bernhardt, E.; Holub, Josef; Hnyk, Drahomír

    2018-01-01

    Roč. 3, č. 16 (2018), s. 4344-4353 ISSN 2365-6549 Institutional support: RVO:61388980 Keywords : Acidity * Carboranes * Computational Chemistry * Delocalization Energy * Electronic Structure Subject RIV: CA - Inorganic Chemistry OBOR OECD: Inorganic and nuclear chemistry

  18. Dilute acid/metal salt hydrolysis of lignocellulosics

    Science.gov (United States)

    Nguyen, Quang A.; Tucker, Melvin P.

    2002-01-01

    A modified dilute acid method of hydrolyzing the cellulose and hemicellulose in lignocellulosic material under conditions to obtain higher overall fermentable sugar yields than is obtainable using dilute acid alone, comprising: impregnating a lignocellulosic feedstock with a mixture of an amount of aqueous solution of a dilute acid catalyst and a metal salt catalyst sufficient to provide higher overall fermentable sugar yields than is obtainable when hydrolyzing with dilute acid alone; loading the impregnated lignocellulosic feedstock into a reactor and heating for a sufficient period of time to hydrolyze substantially all of the hemicellulose and greater than 45% of the cellulose to water soluble sugars; and recovering the water soluble sugars.

  19. Phosphazene-promoted metal-free ring-opening polymerization of ethylene oxide initiated by carboxylic acid

    KAUST Repository

    Zhao, Junpeng

    2014-03-11

    The effectiveness of carboxylic acid as initiator for the anionic ring-opening polymerization of ethylene oxide was investigated with a strong phosphazene base (t-BuP4) used as promoter. Kinetic study showed an induction period, i.e., transformation of carboxylic acid to hydroxyl ester, followed by slow chain growth together with simultaneous and fast end-group transesterification, which led to poly(ethylene oxide) (PEO) consisting of monoester (monohydroxyl), diester, and dihydroxyl species. An appropriate t-BuP4/acid ratio was proven to be essential to achieve better control over the polymerization and low dispersity of PEO. This work provides important information and enriches the toolbox for macromolecular and biomolecular engineering with protic initiating sites. © 2014 American Chemical Society.

  20. Characterization of 1-Aminocyclopropane-1-Carboxylate (ACC) Deaminase-Containing Pseudomonas spp. in the Rhizosphere of Salt-Stressed Canola

    NARCIS (Netherlands)

    Akhgar, A.; Arzanlou, M.; Bakker, Peter; Hamidpour, M.

    2014-01-01

    When exposed to biotic or abiotic stress conditions, plants produce ethylene from its immediate precursor 1-aminocyclopropane-1- carboxylate (ACC), leading to retarded root growth and senescence. Many plant growth-promoting rhizobacteria contain the enzyme ACC deaminase and this enzyme can cleave

  1. The effect of omega-3 carboxylic acids on apolipoprotein CIII-containing lipoproteins in severe hypertriglyceridemia.

    Science.gov (United States)

    Morton, Allyson M; Furtado, Jeremy D; Lee, Jane; Amerine, William; Davidson, Michael H; Sacks, Frank M

    Lipoprotein subspecies containing apoCIII adversely affect cardiovascular disease (CVD) risk; for example, low density lipoprotein (LDL) with apoCIII is a stronger CVD predictor than LDL without apoCIII. The Epanova for Lowering Very High Triglycerides (EVOLVE) trial showed that Epanova (omega-3 carboxylic acids [OM3-CA]) significantly lowered TG and apoCIII but raised LDL-C. However, it is unknown what subspecies of LDL were affected by treatment. To determine how lipoprotein subspecies are affected by omega-3 fatty acid treatment, we studied the effect of OM3-CA on apoCIII concentrations in high density lipoprotein (HDL), LDL, and very low density lipoprotein (VLDL) and on the concentrations of subspecies of HDL, LDL, and VLDL that contain or do not contain apoCIII. We analyzed plasma from a subset of subjects from the EVOLVE trial, a 12-week double-blind study of 399 subjects with fasting TG of 500 to 2000 mg/dL who were randomized to OM3-CA 2, 3, or 4 g/d or olive oil (placebo). OM3-CA significantly reduced plasma apoCIII relative to placebo, as well as apoCIII in HDL, and apoCIII in LDL. Treatment did not significantly affect the concentration of LDL with apoCIII, a subspecies highly associated with CVD risk. OM3-CA increased selectively the concentration of LDL that does not contain apoCIII, a subspecies with a weak relation to coronary heart disease. The reduction in apoCIII was associated with plasma increases in eicosapentaenoic acid, docosahexaenoic acid, and arachidonic acid and decreases in linoleic, palmitic, and oleic acids. Reduction in apoCIII may be a mechanism for the TG-lowering effects of OM3-CA. The increase in LDL-C seen in the EVOLVE trial may not be associated with increased risk of CVD. Copyright © 2016 National Lipid Association. Published by Elsevier Inc. All rights reserved.

  2. Distillation Separation of Hydrofluoric Acid and Nitric Acid from Acid Waste Using the Salt Effect on Vapor-Liquid Equilibrium

    Science.gov (United States)

    Yamamoto, Hideki; Sumoge, Iwao

    2011-03-01

    This study presents the distillation separation of hydrofluoric acid with use of the salt effect on the vapor-liquid equilibrium for acid aqueous solutions and acid mixtures. The vapor-liquid equilibrium of hydrofluoric acid + salt systems (fluorite, potassium nitrate, cesium nitrate) was measured using an apparatus made of perfluoro alkylvinylether. Cesium nitrate showed a salting-out effect on the vapor-liquid equilibrium of the hydrofluoric acid-water system. Fluorite and potassium nitrate showed a salting-in effect on the hydrofluoric acid-water system. Separation of hydrofluoric acid from an acid mixture containing nitric acid and hydrofluoric acid was tested by the simple distillation treatment using the salt effect of cesium nitrate (45 mass%). An acid mixture of nitric acid (5.0 mol · dm-3) and hydrofluoric acid (5.0 mol · dm-3) was prepared as a sample solution for distillation tests. The concentration of nitric acid in the first distillate decreased from 5.0 mol · dm-3 to 1.13 mol · dm-3, and the concentration of hydrofluoric acid increased to 5.41 mol · dm-3. This first distillate was further distilled without the addition of salt. The concentrations of hydrofluoric acid and nitric acid in the second distillate were 7.21 mol · dm-3 and 0.46 mol · dm-3, respectively. It was thus found that the salt effect on vapor-liquid equilibrium of acid mixtures was effective for the recycling of acids from acid mixture wastes.

  3. Quantitative determination of carboxylic acids, amino acids, carbohydrates, ethanol and hydroxymethylfurfural in honey by (1)H NMR.

    Science.gov (United States)

    del Campo, Gloria; Zuriarrain, Juan; Zuriarrain, Andoni; Berregi, Iñaki

    2016-04-01

    A method using (1)H NMR spectroscopy has been developed to quantify simultaneously thirteen analytes in honeys without previous separation or pre-concentration steps. The method has been successfully applied to determine carboxylic acids (acetic, formic, lactic, malic and succinic acids), amino acids (alanine, phenylalanine, proline and tyrosine), carbohydrates (α- and β-glucose and fructose), ethanol and hydroxymethylfurfural in eucalyptus, heather, lavender, orange blossom, thyme and rosemary honeys. Quantification was performed by using the area of the signal of each analyte in the honey spectra, together with external standards. The regression analysis of the signal area against concentration plots, used for the calibration of each analyte, indicates a good linearity over the concentration ranges found in honeys, with correlation coefficients higher than 0.985 for the thirteen quantified analytes. The recovery studies give values over the 93.7-105.4% range with relative standard deviations lower than 7.4%. Good precision, with relative standard deviations over the range of 0.78-5.21% is obtained. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. The Defense-Related Isoleucic Acid Differentially Accumulates in Arabidopsis Among Branched-Chain Amino Acid-Related 2-Hydroxy Carboxylic Acids

    Directory of Open Access Journals (Sweden)

    Rafał P. Maksym

    2018-06-01

    Full Text Available The branched-chain amino acid (BCAA related 2-hydroxy carboxylic acid isoleucic acid (ILA enhances salicylic acid-mediated pathogen defense in Arabidopsis thaliana. ILA has been identified in A. thaliana as its glucose conjugate correlated with the activity of the small-molecule glucosyltransferase UGT76B1, which can glucosylate both salicylic acid and ILA in vitro. However, endogenous levels of the ILA aglycon have not yet been determined in planta. To quantify ILA as well as the related leucic acid (LA and valic acid (VA in plant extracts, a sensitive method based on the derivatization of small carboxylic acids by silylation and gas chromatography–mass spectrometric analysis was developed. ILA was present in all species tested including several monocotyledonous and dicotyledonous plants as well as broadleaf and coniferous trees, whereas LA and VA were only detectable in a few species. In A. thaliana both ILA and LA were found. However, their levels varied during plant growth and in root vs. leaves. ILA levels were higher in 2-week-old leaves and decreased in older plants, whereas LA exhibited a reverted accumulation pattern. Roots displayed higher ILA and LA levels compared to leaves. ILA was inversely related to UGT76B1 expression level indicating that UGT76B1 glucosylates ILA in planta. In contrast, LA was not affected by the expression of UGT76B1. To address the relation of both 2-hydroxy acids to plant defense, we studied ILA and LA levels upon infection by Pseudomonas syringae. LA abundance remained unaffected, whereas ILA was reduced. This change suggests an ILA-related attenuation of the salicylic acid response. Collectively, the BCAA-related ILA and LA differentially accumulated in Arabidopsis, supporting a specific role and regulation of the defense-modulating small-molecule ILA among these 2-hydroxy acids. The new sensitive method will pave the way to further unravel their role in plants.

  5. Evaluation of the efficacy of chelating agent of catechol amino carboxylic acid for removal of radiothorium

    International Nuclear Information System (INIS)

    Chen Honghong; Hu Yuxing; Wang Yinghua; Jin Meiying; Luo Meichu; Sun Meizhen

    2003-01-01

    The efficacy of prompt single and consecutive administration of chelating agent 7601 and 9501 of catechol amino carboxylic acid for the decorporation of 234 Th in rats and mice was investigated. DTPA was used as positive control. The complexing competitive abilities of 7601 and 9501 to mobilize the thorium with bovine serum albumin were studied with gel chromatography in vitro. The inhibition effect of 7601 and 9501 on superoxide anions radicals (O 2 -. ) were measured with electron spin resonance. The results showed that 7601 and 9501 could increase the excretion of 234 Th in urine and faces by 63%-70% and decrease markedly retention of 234 Th in liver and skeleton, which have been proved to be superior to DTPA. Their different bioactivities for decorporation of 234 Th were consistent with their competitive abilities to mobilize the thorium with bovine serum albumin. 7601 and 9501 could directly scavenge O 2 -. . Their effects as an O 2 -. scavenger were very significant and were similar to the of BESOD. The mechanism of protective effects of 7601 and 9501 for internal exposure injury was close related to decorporation effectiveness and the activity of scavenging oxygen free radical

  6. Jasmonic acid carboxyl methyltransferase regulates development and herbivory-induced defense response in rice.

    Science.gov (United States)

    Qi, Jinfeng; Li, Jiancai; Han, Xiu; Li, Ran; Wu, Jianqiang; Yu, Haixin; Hu, Lingfei; Xiao, Yutao; Lu, Jing; Lou, Yonggen

    2016-06-01

    Jasmonic acid (JA) and related metabolites play a key role in plant defense and growth. JA carboxyl methyltransferase (JMT) may be involved in plant defense and development by methylating JA to methyl jasmonate (MeJA) and thus influencing the concentrations of JA and related metabolites. However, no JMT gene has been well characterized in monocotyledon defense and development at the molecular level. After we cloned a rice JMT gene, OsJMT1, whose encoding protein was localized in the cytosol, we found that the recombinant OsJMT1 protein catalyzed JA to MeJA. OsJMT1 is up-regulated in response to infestation with the brown planthopper (BPH; Nilaparvata lugens). Plants in which OsJMT1 had been overexpressed (oe-JMT plants) showed reduced height and yield. These oe-JMT plants also exhibited increased MeJA levels but reduced levels of herbivore-induced JA and jasmonoyl-isoleucine (JA-Ile). The oe-JMT plants were more attractive to BPH female adults but showed increased resistance to BPH nymphs, probably owing to the different responses of BPH female adults and nymphs to the changes in levels of H2 O2 and MeJA in oe-JMT plants. These results indicate that OsJMT1, by altering levels of JA and related metabolites, plays a role in regulating plant development and herbivore-induced defense responses in rice. © 2015 Institute of Botany, Chinese Academy of Sciences.

  7. Acute toxicity assessment of perfluorinated carboxylic acids towards the Baltic microalgae.

    Science.gov (United States)

    Latała, Adam; Nędzi, Marcin; Stepnowski, Piotr

    2009-09-01

    The presence of high-energy carbon-fluorine bonds in perfluoro compounds lends them great stability and causes them to be environmentally persistent. Relatively little is known about the acute toxicity of perfluorinated carboxylic acids (PFCAs) to ecotoxicological markers such as aquatic plants and animals. This study tested the toxicity of these compounds to the green alga Chlorella vulgaris, the diatom Skeletonema marinoi and the blue-green alga Geitlerinema amphibium, which are species representative of the algal flora of the Baltic Sea. The EC(50) values obtained range from 0.28 mM to 12.84 mM. A distinct relationship between hydrophobicity and toxicity is demonstrated. For every extra perfluoromethylene group in the alkyl chain, the toxicity increases twofold. LogEC(50) values are very well correlated linearly with both the number of carbon atoms in the perfluoroalkyl chain and the partition coefficients. The results also indicate that there are clear differences between the responses of particular taxonomic groups of algae: blue-green algae and diatoms are far more sensitive to PFCAs than green algae, probably because of differences in cell wall structure.

  8. Synthesis, spectroscopic and DFT studies of novel 4-(morpholinomethyl)-5-oxo-1-phenylpyrrolidine-3-carboxylic acid

    Science.gov (United States)

    Devi, Poornima; Fatma, Shaheen; Bishnoi, Abha; Srivastava, Krishna; Shukla, Shraddha; Kumar, Roop

    2018-04-01

    A novel 4-(morpholinomethyl)-5-oxo-1-phenylpyrrolidine-3-carboxylic acid has been synthesized and its structural elucidation has been done by UV, FT-IR, 1H and 13C NMR spectroscopy. All quantum chemical calculations were carried out at level of density functional theory (DFT) with B3LYP function using 6-31G (d, p) basis atomic set. AIM approach has been incorporated for the analysis of various intermolecular interactions. Polarizability and hyperpolarizabilities values have been calculated along with the exploration of nonlinear optical properties of the title compound. DFT computed total first static hyperpolarizability (β0 = 0.2747 × 10-30 esu) indicates that title molecule could be an area of interest as an attractive future NLO material. For the analysis of thermal behaviour of title molecule, thermodynamic properties such as heat capacity, entropy and enthalpy change at various temperatures have been calculated. The NBO computations were done for the correlation of possible transitions with the electronic transitions. Electrophilic and nucleophilic regions were identified with the help of MESP plot. Determination of energy gap has been done by using HOMO and LUMO energy values, along with the computation of electronegativity and electrophilicity indices.

  9. Synthesis, Antifungal Activity and QSAR of Some Novel Carboxylic Acid Amides

    Directory of Open Access Journals (Sweden)

    Shijie Du

    2015-03-01

    Full Text Available A series of novel aromatic carboxylic acid amides were synthesized and tested for their activities against six phytopathogenic fungi by an in vitro mycelia growth inhibition assay. Most of them displayed moderate to good activity. Among them N-(2-(1H-indazol-1-ylphenyl-2-(trifluoromethylbenzamide (3c exhibited the highest antifungal activity against Pythium aphanidermatum (EC50 = 16.75 µg/mL and Rhizoctonia solani (EC50 = 19.19 µg/mL, compared to the reference compound boscalid with EC50 values of 10.68 and 14.47 µg/mL, respectively. Comparative molecular field analysis (CoMFA and comparative molecular similarity indices analysis (CoMSIA were employed to develop a three-dimensional quantitative structure-activity relationship model for the activity of the compounds. In the molecular docking, a fluorine atom and the carbonyl oxygen atom of 3c formed hydrogen bonds toward the hydroxyl hydrogens of TYR58 and TRP173.

  10. A Precise Method for Processing Data to Determine the Dissociation Constants of Polyhydroxy Carboxylic Acids via Potentiometric Titration.

    Science.gov (United States)

    Huang, Kaixuan; Xu, Yong; Lu, Wen; Yu, Shiyuan

    2017-12-01

    The thermodynamic dissociation constants of xylonic acid and gluconic acid were studied via potentiometric methods, and the results were verified using lactic acid, which has a known pKa value, as a model compound. Solutions of xylonic acid and gluconic acid were titrated with a standard solution of sodium hydroxide. The determined pKa data were processed via the method of derivative plots using computer software, and the accuracy was validated using the Gran method. The dissociation constants associated with the carboxylic acid group of xylonic and gluconic acids were determined to be pKa 1  = 3.56 ± 0.07 and pKa 1  = 3.74 ± 0.06, respectively. Further, the experimental data showed that the second deprotonation constants associated with a hydroxyl group of each of the two acids were pKa 2  = 8.58 ± 0.12 and pKa 2  = 7.06 ± 0.08, respectively. The deprotonation behavior of polyhydroxy carboxylic acids was altered using various ratios with Cu(II) to form complexes in solution, and this led to proposing a hypothesis for further study.

  11. Teratology study of amide derivatives of branched aliphatic carboxylic acids with 4-aminobenzensulfonamide in NMRI mice.

    Science.gov (United States)

    Onishi, Yuko; Okada, Akinobu; Noyori, Hiroko; Okamura, Ai; Hen, Naama; Yagen, Boris; Bialer, Meir; Fujiwara, Michio

    2013-08-01

    Valproic acid (VPA), widely used to treat epilepsy, bipolar disorders, and migraine prophylaxis, is known to cause neural tube and skeletal defects in humans and animals. Aminobenzensulfonamide derivatives of VPA with branched aliphatic carboxylic acids, namely 2-methyl-N-(4-sulfamoyl-phenyl)-pentanamide (MSP), 2-ethyl-N-(4-sulfamoyl-phenyl)-butyramide (ESB), 2-ethyl-4-methyl-N-(4-sulfamoyl-phenyl)-pentanamide (EMSP), and 2-ethyl-N-(4-sulfamoyl-benzyl)-butyramide (ESBB), have shown more potent anticonvulsant activity than VPA in preclinical testing. Here, we investigated the teratogenic effects of these analogous compounds of VPA in NMRI mice. Pregnant NMRI mice were given a single subcutaneous injection of either VPA at 1.8 or 3.6 mmol/kg, or MSP, ESB, EMSP, or ESBB at 1.8, 3.6, or 4.8 mmol/kg on gestation day (GD) 8. Cesarean section was performed on GD 18, and the live fetuses were examined for external and skeletal malformations. Compared with VPA, which induced neural tube defects (NTDs) in fetuses at 1.8 and 3.6 mmol/kg, the analog derivatives induced no NTDs at dose levels up to 4.8 mmol/kg (except for a single case of exencephaly at 4.8 mmol/kg MSP). Skeletal examination showed several abnormalities mainly at the axial skeletal level with VPA at 1.8 mmol/kg. Fused vertebrae and/or fused ribs were also observed with MSP, ESB, EMSP, and ESBB, they were less severe and seen at a lower incidence that those induced by VPA at the same dose level. In addition to exerting more potent preclinical antiepileptic activity, teratology comparison indicates that aminobenzensulfonamide analogs are generally more weakly teratogenic than VPA. © 2013 Wiley Periodicals, Inc.

  12. Synthesis of carboxylic acids, esters, alcohols and ethers containing a tetrahydropyran ring derived from 6-methyl-5-hepten-2-one.

    Science.gov (United States)

    Hanzawa, Yohko; Hashimoto, Kahoko; Kasashima, Yoshio; Takahashi, Yoshiko; Mino, Takashi; Sakamoto, Masami; Fujita, Tsutomu

    2012-01-01

    3-hydroxy acids, 3-hydroxy-3,7-dimethyloct-6-enoic acid (1) and 3-hydroxy-2,2,3,7-tetramethyloct-6-enoic acid (2), were prepared from 6-methyl-5-hepten-2-one, and they were subsequently used to prepare (2,6,6-trimethyltetrahydropyran-2-yl)acetic acid (3) and 2-methyl-2-(2,6,6-trimethyltetrahydropyran-2-yl)propanoic acid (4), respectively, via cyclization with an acidic catalyst such as boron trifluoride diethyl etherate or iodine. The reaction of carboxylic acids 3 and 4 with alcohols, including methanol, ethanol, and 1-propanol, produced the corresponding methyl, ethyl, and propyl esters, which all contained a tetrahydropyran ring. Reduction of carboxylic acids 3 and 4 afforded the corresponding alcohols. Subsequent reactions of these alcohols with several acyl chlorides produced novel esters. The alcohols also reacted with methyl iodide and sodium hydride to provide novel ethers. A one-pot cyclization-esterification of 1 to produce esters containing a tetrahydropyran ring, using iodine as a catalyst, was also investigated.

  13. Quantification of the xylem-to-phloem transfer of amino acids by use of inulin (14C)carboxylic acid as xylem transfer marker

    International Nuclear Information System (INIS)

    Van Bel, A.J.

    1984-01-01

    Inulin ( 14 C)carboxylic acid and 14 C-labelled amino acid (α-aminoisobutyric acid (aib) and valine) solutions were introduced into the transpiration stream through the cut stem bases of young (4-12 leaves) tomato plants. Inulin carboxylic acid (inu) was translocated exclusively by the xylem, whereas the amino acid distribution resulted from both xylem and phloem import. Comparison of the distribution of inu and aib permitted a quantitative assessment of the xylem-to-phloem transfer in the stem. Of aib, 20.6% traversed from xylem to phloem in a plant with 12 leaves. The phloem import was not evenly distributed over the leaves and varied from 0% (first five leaves) to 95% (top leaf) of the aib import per leaf. Doubling the flow rates in the xylem reduced the aib supply to 25% in the top leaf and 55% in the next leaf, which reflects a reduced xylem-to-phloem transfer. (author)

  14. A Convenient One-Pot Method for the Synthesis of N-Methoxy-N-methyl Amides from Carboxylic Acids

    International Nuclear Information System (INIS)

    Kim, Joong Gon; Jang, Doo Ok

    2010-01-01

    We have developed a mild and convenient method for one-pot synthesis of Weinreb amides from carboxylic acids. The process is general for the preparation of Weinreb amides from a variety of carboxylic acids. The reaction was also applicable to the preparation of α-amino Weinreb amides and proceeded without deprotection of the N-Fmoc protecting group or racemization of the stereogenic centers. N-Methoxy-N-methyl amides, or Weinreb amides, have been widely used as versatile synthetic intermediates in organic syntheses. These amides serve as excellent acylating agents for organolithium or organomagnesium reagents and as robust aldehyde group equivalents. The utility of Weinreb amides has been extended to the preparation of N-protected amino aldehydes, useful intermediates for many chemoselective transformations in peptide chemistry

  15. Ionic networks derived from the protonation of dendritic amines with carboxylic acid end‐functionalized PEGs

    DEFF Research Database (Denmark)

    Gonzalez, Lidia; Skov, Anne Ladegaard; Hvilsted, Søren

    2013-01-01

    The synthesis and characterization of novel ionic networks linked by the ammonium salts of poly(propylene imine) (PPI) dendrimers of the first (PPI G1) and second (PPI G2) generation and two short bis carboxymethyl ether terminated poly(ethylene glycol)s (DiCOOH‐PEG) with different molecular...... weights (Mn ∼ 250 and Mn ∼ 600) are reported. Likewise, an ionic network based on PPI G1 and a long αω‐dicarboxylic acid functionalized PEG (Mn ∼ 4800) were evaluated. Simpler ionic structures based on tris(2‐aminoethyl)amine or hexamethylene diamine and the short DiCOOH‐PEGs are also investigated....... The ionic structures formed were confirmed by differential scanning calorimetry, Fourier Transform Infrared spectroscopy in the attenuated‐total‐reflection mode, and 1H‐13C NMR spectroscopy. A comprehensive 1H NMR analysis revealed that only the primary amines of the PPI G1 dendrimer residing...

  16. Perfluorinated carboxylic acids in human breast milk from Spain and estimation of infant's daily intake

    Energy Technology Data Exchange (ETDEWEB)

    Motas Guzmàn, Miguel [Área de Toxicología, Universidad de Murcia, Campus de Espinardo, 30100 Murcia (Spain); Clementini, Chiara [University of Siena, Department of Physical Sciences, Earth and Environment, Via Mattioli, 4, 53100 Siena (Italy); Pérez-Cárceles, Maria Dolores; Jiménez Rejón, Sandra [Department of Legal Medicine, School of Medicine, University of Murcia & Instituto Murciano de Investigacion Biomedica (IMIB), (IMIB-VIRGEN DE LA ARRIXACA), Murcia (Spain); Cascone, Aurora; Martellini, Tania [Department of Chemistry “Ugo Schiff”, via della Lastruccia 3, 50019 Sesto Fiorentino, Firenze (Italy); Guerranti, Cristiana [University of Siena, Department of Physical Sciences, Earth and Environment, Via Mattioli, 4, 53100 Siena (Italy); Bioscience Research Center, Via Aurelia Vecchia 32, 58015 Orbetello, GR (Italy); Cincinelli, Alessandra, E-mail: acincinelli@unifi.it [Department of Chemistry “Ugo Schiff”, via della Lastruccia 3, 50019 Sesto Fiorentino, Firenze (Italy)

    2016-02-15

    Human milk samples were collected from 67 mothers in 2014 at a Primary Care Centre in Murcia (Spain) and analyzed for perfluorinated carboxylic acids (PFCAs). Concentrations measured for perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), perfluoroundecanoic acid (PFUnDA) and perfluorododecanoic acid (PFDoDA) ranged from < LOQ (< 10 ng/L) to 397 ng/L with a mean concentration of 66 ± 68 ng/L and a median of 29 ng/L. The presence of these compounds was revealed in 50 samples out of 67 analyzed. Influence of number of pregnancies and food habits on PFCAs concentrations was also investigated. Statistically significant differences in PFCA levels were found when the women were divided into maternal age classes and into the categories primiparae and multiparae. A greater transfer of PFC during breastfeeding by primiparous was evidenced and thus a higher exposure to these contaminants for the first child. Moreover, it was possible to hypothesize that the content of PFCs is in general correlated to the eating habits of donors and, in particular, with the fish consumption. Finally, PFOA daily intakes and risk index (RI) were estimated for the first six months of life and we found that ingestion rates of PFOA did not exceed the tolerable daily intake (TDI) recommended by the European Food Safety Authority (EFSA). - Graphical abstract: Figure SI 1. Concentrations (ng/L) of PFCs recovered in 67 samples of human breast milk. - Highlights: • Perfluorinated carboxylic acids were analyzed in a set of 67 breast milk samples collected from Spanish women. • PFOA appeared as the major contributor to the total perfluorinated carboxylic acids. • PFOA concentrations were significantly higher in milk of primiparous participants. • PFOA daily intake and risk index were estimated for the firsts six month of life.

  17. Perfluorinated carboxylic acids in human breast milk from Spain and estimation of infant's daily intake

    International Nuclear Information System (INIS)

    Motas Guzmàn, Miguel; Clementini, Chiara; Pérez-Cárceles, Maria Dolores; Jiménez Rejón, Sandra; Cascone, Aurora; Martellini, Tania; Guerranti, Cristiana; Cincinelli, Alessandra

    2016-01-01

    Human milk samples were collected from 67 mothers in 2014 at a Primary Care Centre in Murcia (Spain) and analyzed for perfluorinated carboxylic acids (PFCAs). Concentrations measured for perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), perfluoroundecanoic acid (PFUnDA) and perfluorododecanoic acid (PFDoDA) ranged from < LOQ (< 10 ng/L) to 397 ng/L with a mean concentration of 66 ± 68 ng/L and a median of 29 ng/L. The presence of these compounds was revealed in 50 samples out of 67 analyzed. Influence of number of pregnancies and food habits on PFCAs concentrations was also investigated. Statistically significant differences in PFCA levels were found when the women were divided into maternal age classes and into the categories primiparae and multiparae. A greater transfer of PFC during breastfeeding by primiparous was evidenced and thus a higher exposure to these contaminants for the first child. Moreover, it was possible to hypothesize that the content of PFCs is in general correlated to the eating habits of donors and, in particular, with the fish consumption. Finally, PFOA daily intakes and risk index (RI) were estimated for the first six months of life and we found that ingestion rates of PFOA did not exceed the tolerable daily intake (TDI) recommended by the European Food Safety Authority (EFSA). - Graphical abstract: Figure SI 1. Concentrations (ng/L) of PFCs recovered in 67 samples of human breast milk. - Highlights: • Perfluorinated carboxylic acids were analyzed in a set of 67 breast milk samples collected from Spanish women. • PFOA appeared as the major contributor to the total perfluorinated carboxylic acids. • PFOA concentrations were significantly higher in milk of primiparous participants. • PFOA daily intake and risk index were estimated for the firsts six month of life.

  18. Syntheses, structures, photoluminescence and photocatalysis of 2D layered lanthanide-carboxylates with 2, 2′-dithiodibenzoic acid

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Ling; Zhong, Jie-Cen; Qiu, Xing-Tai; Sun, Yan-Qiong, E-mail: sunyq@fzu.edu.cn; Chen, Yi-Ping

    2017-02-15

    Two series of lanthanide-carboxylates, [Ln(2,2′-dtba)(2,2′-Hdtba)(EtOH)]{sub n} (I:Ln=Eu(1a), Dy(1b)) and [Ln(2,2′-dtba)(2,2′-Hdtba)(4,4′-bpy){sub 0.5}]{sub n} (II:Ln=Eu(2a), Dy(2b), Tb(2c) 2,2′-H{sub 2}dtba=2,2′-dithiodibenzoic acid, 4,4′-bpy=4,4′-bipyridine) have been synthesized under hydrothermal conditions. Interestingly, the H{sub 2}dtba organic ligand was generated by in situ S–S reaction of 2-mercaptobenzoic acid. Compounds I and II possess different 2D layered structures based on similar 1D [Ln(2,2′-dtba)]{sup +} chains. Photoluminescence studies reveal that compounds I and II exhibit strong lanthanide characteristic emission bands. Remarkably, Compounds 1b and 2a both exhibit good photocatalytic activity for degradation of Rhodamine-B (Rh-B) under the simulated sunlight irradiation. - Graphical abstract: Two series of lanthanide-carboxylates have been in situ synthesized under hydrothermal conditions. The lanthanide-carboxylates exhibit strong lanthanide characteristic emission bands and good photocatalytic activity for degradation of Rhodamine-B. - Highlights: • 2D layered lanthanide-carboxylates with 2,2′-dithiodibenzoic acid. • In situ S–S reaction of 2-mercaptobenzoic acid under hydrothermal condition. • The Emission spectra of I and II exhibit the characteristic transition of lanthanide ions. • Compounds 1b and 2a exhibit good photocatalytic activity for degradation of Rhodamine-B.

  19. Synthesis of 1-Methyl-3-oxo-7-oxabicyclo[2.2.1]hept-5-ene-2-carboxylic Acid Methyl Ester

    Directory of Open Access Journals (Sweden)

    Gil Valdo José da Silva

    2005-11-01

    Full Text Available A simple and efficient method for the preparation of 1-methyl-3-oxo-7- oxabicyclo[2.2.1]hept-5-en-2-carboxylic acid methyl ester (1 is described. The first step is a highly regioselective Diels-Alder reaction between 2-methylfuran and methyl-3-bromo- propiolate. A remarkably difficult ketal hydrolysis reaction was effected by treatment with HCl, a simple reagent that was shown to be more efficient, in this case, than commonly used more elaborate methods.

  20. Palladium-Catalyzed Decarboxylative γ-Olefination of 2,5-Cyclohexadiene-1-carboxylic Acid Derivatives with Vinyl Halides.

    Science.gov (United States)

    Chang, Chi-Hao; Chou, Chih-Ming

    2018-04-06

    This study explores a Pd-catalyzed decarboxylative Heck-type Csp 3 -Csp 2 coupling reaction of 2,5-cyclohexadiene-1-carboxylic acid derivatives with vinyl halides to provide γ-olefination products. The olefinated 1,3-cyclohexadienes can be further oxidized to produce meta-alkylated stilbene derivatives. Additionally, the conjugated diene products can also undergo a Diels-Alder reaction to produce a bicyclo[2.2.2]octadiene framework.

  1. Cofactor balance by nicotinamide nucleotide transhydrogenase (NNT) coordinates reductive carboxylation and glucose catabolism in the tricarboxylic acid (TCA) cycle.

    Science.gov (United States)

    Gameiro, Paulo A; Laviolette, Laura A; Kelleher, Joanne K; Iliopoulos, Othon; Stephanopoulos, Gregory

    2013-05-03

    Cancer and proliferating cells exhibit an increased demand for glutamine-derived carbons to support anabolic processes. In addition, reductive carboxylation of α-ketoglutarate by isocitrate dehydrogenase 1 (IDH1) and 2 (IDH2) was recently shown to be a major source of citrate synthesis from glutamine. The role of NAD(P)H/NAD(P)(+) cofactors in coordinating glucose and glutamine utilization in the tricarboxylic acid (TCA) cycle is not well understood, with the source(s) of NADPH for the reductive carboxylation reaction remaining unexplored. Nicotinamide nucleotide transhydrogenase (NNT) is a mitochondrial enzyme that transfers reducing equivalents from NADH to NADPH. Here, we show that knockdown of NNT inhibits the contribution of glutamine to the TCA cycle and activates glucose catabolism in SkMel5 melanoma cells. The increase in glucose oxidation partially occurred through pyruvate carboxylase and rendered NNT knockdown cells more sensitive to glucose deprivation. Importantly, knocking down NNT inhibits reductive carboxylation in SkMel5 and 786-O renal carcinoma cells. Overexpression of NNT is sufficient to stimulate glutamine oxidation and reductive carboxylation, whereas it inhibits glucose catabolism in the TCA cycle. These observations are supported by an impairment of the NAD(P)H/NAD(P)(+) ratios. Our findings underscore the role of NNT in regulating central carbon metabolism via redox balance, calling for other mechanisms that coordinate substrate preference to maintain a functional TCA cycle.

  2. Hydrogen-bonding interactions in thiosemicarbazones of carboxylic acids: Structure of 2-ketobutyric acid thiosemicarbazone hemihydrate

    International Nuclear Information System (INIS)

    Sonawane, P.; Chikate, R.; Kumbhar, A.; Padhye, S.; Doedens, R.J.

    1991-01-01

    2-Thiosemicarbazonobutanoic acid hemihydrate, C 5 H 9 N 3 O 2 S.0.5H 2 O, M r =184.22, triclinic, Panti 1, a=8.163(2), b=8.868(2), c=12.438(2) A, α=72.99(2), β=79.47(2), γ=84.06(2)deg, V=845.3(3) A 3 , Z=4, D x =1.447 Mg m -3 , λ(Mo Kα)=0.71073 A, μ=0.332 mm -1 , F(000)=392, T=296 K, R=0.038 for 3830 independent reflections with I>3σ(I). Three hydrogen bonds link the two crystallographically independent molecules in a pairwise fashion. The two molecules both have E configurations about each C-N and N-N bond, but differ by nearly 180deg in the orientation of the -COOH group. (orig.)

  3. Developmental Toxicity of (4S-2- (4-hydroxy-3-methoxyphenyl thiazolidine-4-carboxylic acid in Zebrafish ( Danio rerio

    Directory of Open Access Journals (Sweden)

    Cansu Akbulut

    2017-08-01

    Full Text Available ABSTRACT (4S-2-(4-hydroxy-3-methoxyphenylthiazolidine-4-carboxylic acid is new synthesized substance obtained from cysteine and valine. Thiazolidine derivates have important biological responses so scientists work intensively on these compounds in recent years. It is obvious that thiazolidine contained compounds will be used in future in the pharmaceutical industry to treat important diseases. Median lethal concentrations (LC50 for 48 h and 96 h were found as 1.106±0.052 mM and 0.804mM ± 0.102 respectively. According to LC50, exposure doses were determined as control, 0.4 mM, 0.2 mM and 0.1 mM (4S-2-(4-hydroxy-3-methoxyphenylthiazolidine-4-carboxylic acid. Developmental toxicity and apoptotic features on zebrafish development were evaluated in this study. The results of this study indicate that (4S-2-(4-hydroxy-3-methoxyphenylthiazolidine-4-carboxylic acid exposure cause developmental defects like pericardial edema, bent spine, tail malformation, blood accumulation, yolk sac edema but on the other hand concentration-dependent decrease in apoptotic rate. Likewise, concentration-dependent decrease in hatching and increase in mortality of embryos were also detected.

  4. Influence of indium-tin oxide surface structure on the ordering and coverage of carboxylic acid and thiol monolayers

    International Nuclear Information System (INIS)

    Cerruti, Marta; Rhodes, Crissy; Losego, Mark; Efremenko, Alina; Maria, Jon-Paul; Fischer, Daniel; Franzen, Stefan; Genzer, Jan

    2007-01-01

    This paper analyses the variability of self-assembled monolayers (SAMs) formation on ITO depending on the substrate surface features. In particular, we report on the formation of carboxylic acid- and thiol-based SAMs on two lots of commercially prepared indium-tin oxide (ITO) thin films. Contact angle measurements, electrochemical experiments, and near-edge x-ray absorption fine structure (NEXAFS) spectroscopy showed that the quality of monolayers formed differed substantially between the two ITO batches. Only one of the two ITO substrates was capable of forming well-organized thiol- and carboxylic acid-based SAMs. In order to rationalize these observations, atomic force microscopy and x-ray diffraction analyses were carried out, and SAMs were prepared on ITO substrates fabricated by sputtering in our laboratories. An attempt was made to influence the film microstructure and surface morphology by varying substrate temperatures during ITO deposition. Good-quality thiol and carboxylic acid SAMs were obtained on one of the ITO substrates prepared in-house. While our characterization could not single out conclusively one specific parameter in ITO surface structure that could be responsible for good SAMs formation, we could point out homogeneous surface morphology as a relevant factor for the quality of the SAMs. Evidence was also found for ITO crystallographic orientation to be a parameter influencing SAMs organization

  5. Changes of sour taste and the composition of carboxylic acids induced in brewed coffee by γ-irradiation on green beans and storage of roast beans

    International Nuclear Information System (INIS)

    Tomoda, Goro; Matsuyama, Jun; Nagano, Akiko; Namatame, Mitsuko; Morita, Yoshiaki.

    1980-01-01

    Brazil santos green coffee beans were irradiated with 60 Co-γ rays at doses of 0, 0.05, 0.5 and 1.5 Mrad respectively and changes of the composition of carboxylic acids in roast beans were analyzed by means of GLC together with those of the organoleptic properties of roast beans during storage by use of the cup testing. The total acid content immediately after roasting was about 6,000 mg/100 g (roast beans) and the composition of carboxylic acids was as follows. Chlorogenic acid: hydroxy-carboxylic acids: mono-carboxylic acid: others = 73 : 18 : 7 : 2. Fresh coffee flavour was influenced markedly especially in acid taste by both irradiation of γ-rays on green beans and storage of roast beans, because of the change of above acids composition. On γ-ray irradiation, the change of the acid composition were more clear than that of stored roast beans. Therefore, the quality of γ-irradiated coffee beans seems to be closely associated with the ratio of hydroxy-carboxylic acids mg/ monocarboxylic acids mg, but little with total acid content. (author)

  6. Analysis of perfluorinated carboxylic acids in soils II: optimization of chromatography and extraction.

    Science.gov (United States)

    Washington, John W; Henderson, W Matthew; Ellington, J Jackson; Jenkins, Thomas M; Evans, John J

    2008-02-15

    With the objective of detecting and quantitating low concentrations of perfluorinated carboxylic acids (PFCAs), including perfluorooctanoic acid (PFOA), in soils, we compared the analytical suitability of liquid chromatography columns containing three different stationary phases, two different liquid chromatography-tandem mass spectrometry (LC/MS/MS) systems, and eight combinations of sample-extract pretreatments, extractions and cleanups on three test soils. For the columns and systems we tested, we achieved the greatest analytical sensitivity for PFCAs using a column with a C(18) stationary phase in a Waters LC/MS/MS. In this system we achieved an instrument detection limit for PFOA of 270 ag/microL, equating to about 14 fg of PFOA on-column. While an elementary acetonitrile/water extraction of soils recovers PFCAs effectively, natural soil organic matter also dissolved in the extracts commonly imparts significant noise that appears as broad, multi-nodal, asymmetric peaks that coelute with several PFCAs. The intensity and elution profile of this noise is highly variable among soils and it challenges detection of low concentrations of PFCAs by decreasing the signal-to-noise contrast. In an effort to decrease this background noise, we investigated several methods of pretreatment, extraction and cleanup, in a variety of combinations, that used alkaline and unbuffered water, acetonitrile, tetrabutylammonium hydrogen sulfate, methyl-tert-butyl ether, dispersed activated carbon and solid-phase extraction. For the combined objectives of complete recovery and minimization of background noise, we have chosen: (1) alkaline pretreatment; (2) extraction with acetonitrile/water; (3) evaporation to dryness; (4) reconstitution with tetrabutylammonium-hydrogen-sulfate ion-pairing solution; (5) ion-pair extraction to methyl-tert-butyl ether; (6) evaporation to dryness; (7) reconstitution with 60/40 acetonitrile/water (v/v); and (8) analysis by LC/MS/MS. Using this method, we

  7. [14C]-radiolabeling of {[trans-(8β)]-6-methyl-1-(1-methylethyl) ergoline-8-carboxylic acid, 4-methoxycyclohexyl ester (Z)-2-buteneidioate (1:1)}

    International Nuclear Information System (INIS)

    Marzoni, G.; Wheeler, W.J.; Garbrecht, W.L.

    1988-01-01

    The 5HT 2 -receptor antagonist, [ 14 C]-labeled brace[trans-(8β)]-6-methyl-1-(1-methylethyl)ergoline-8-carboxylic acid, 4-methoxycyclohexyl ester (Z)-2-butenedioate (1:1)brace (LY281067) was synthesized from unlabeled 6-methyl-1-(1-methylethyl)ergoline-8-carboxylic acid. The [ 14 C] label was introduced into the carboxyl group attached to the 8 position of the ergoline nucleus. This site is stable to metabolism. The synthesis involves removal of an unlabeled carboxyl group and subsequent reinsertion of a [ 14 C]-labeled carboxyl group into the same position. The radiolabel is not introduced until near the end of the synthesis which allows for ease of handling and scale-up of intermediates. (author)

  8. 76 FR 34044 - Citric Acid and Certain Citrate Salts From Canada: Final Results of Antidumping Duty...

    Science.gov (United States)

    2011-06-10

    ... DEPARTMENT OF COMMERCE International Trade Administration [A-122-853] Citric Acid and Certain... the antidumping duty order on citric acid and certain citrate salts (citric acid) from Canada. The... order on citric acid from Canada. See Citric Acid and Certain Citrate Salts From Canada: Preliminary...

  9. Preparation of porous monolayer film by immersing the stearic acid Langmuir-Blodgett monolayer on mica in salt solution

    Energy Technology Data Exchange (ETDEWEB)

    Wang, S. [Institute of Near-Field Optics and Nano Technology, School of Physics and Optoelectronic Technology, Dalian University of Technology, Street No. 2 Linggong Road, Dalian 116024 (China); Li, Y.L.; Zhao, H.L.; Liang, H. [Institute of Photo-Biophysics, School of Physics and Electronic, Henan University, Jinming, Kaifeng 475004, Henan (China); Liu, B., E-mail: boliu@henu.edu.cn [Institute of Photo-Biophysics, School of Physics and Electronic, Henan University, Jinming, Kaifeng 475004, Henan (China); Pan, S., E-mail: span@dlut.edu.cn [Institute of Near-Field Optics and Nano Technology, School of Physics and Optoelectronic Technology, Dalian University of Technology, Street No. 2 Linggong Road, Dalian 116024 (China)

    2012-11-15

    Highlights: Black-Right-Pointing-Pointer Porous film has been prepared by immersing the stearic acid Langmuir-Blodgett monolayer on mica in salt solution. Black-Right-Pointing-Pointer The mechanism relies on the electrostatic screening effect of the cations in salt solution. Black-Right-Pointing-Pointer The factors influencing the size and area of the pores were investigated. - Abstract: Porous materials have drawn attention from scientists in many fields such as life sciences, catalysis and photonics since they can be used to induce some materials growth as expected. Especially, porous Langmuir-Blodgett (LB) film is an ideal material with controlled thickness and flat surface. In this paper, stearic acid (SA), which has been extensively explored in LB film technique, is chosen as the template material with known parameters to prepare the LB film, and then the porous SA monolayer film is obtained by means of etching in salt solution. The main etching mechanism is suggested that the cations in the solution block the electrostatic interaction between the polar carboxyl group of SA and the electronegative mica surface. The influencing factors (such as concentration of salt solution, valence of cation and surface pressure) of the porous SA film are systematically studied in this work. The novel method proposed in this paper makes it convenient to prepare porous monolayer film for designed material growth or cell culture.

  10. Microencapsulated acids associated with essential oils and acid salts for piglets in the nursery phase

    Directory of Open Access Journals (Sweden)

    Marco Aurelio Callegari

    2016-08-01

    Full Text Available The objective of this study was to evaluate the use of commercial blends of organic and inorganic acids combined with essential oils for piglets in the nursery phase. The formulations were administered as microcapsules or as acid salts. Ninety-six, Pen Ar Lan, barrow and female piglets, weaned at a body weight of 600 kg ± 12 kg and age of 23 days were subjected to four treatments. The animals were distributed in randomized blocks of three animals per pen and 8 replicates per treatment. The treatments consisted of four different diets: control (free of organic acids; acid and essential oil blends (fumaric acid 10,5%, malic acid 8.0%, essential oils; in microencapsulated form; microencapsulated acid blend (phosphoric acid 10%, citric acid 10%, malic acid 10%, fumaric acid 20%; in microencapsulated form; and acid salt blend (formic acid 40.5%, phosphoric acid 13.6%, propionic acid 4.9% and salts (23.2% calcium and 4.4% phosphorus available. The performance parameters, digestive transit time, weights of organs of the digestive tract, bacterial count of feces (Lactobacillus, E coli and Salmonella ssp and Clostridium, pH of the stomach and duodenal content did not differ between treatment groups (P > 005. All treatments containing organic acids exhibited positive effects on diarrhea control (P < 005. The cecal contents of volatile fatty acids (VFA were higher in piglets fed diets containing acids than in animals that received the control diet (P < 005, and blends containing essential oils improved the jejunum villus height compared with the control group. The use of diets containing acids improved diarrhea control and VFA production in the cecum, and specifically the diets containing microencapsulated acid blends required the lowest doses to be effective.

  11. Effects of Spray Drying on Physicochemical Properties of Chitosan Acid Salts

    OpenAIRE

    Cervera, Mirna Fernández; Heinämäki, Jyrki; de la Paz, Nilia; López, Orestes; Maunu, Sirkka Liisa; Virtanen, Tommi; Hatanpää, Timo; Antikainen, Osmo; Nogueira, Antonio; Fundora, Jorge; Yliruusi, Jouko

    2011-01-01

    The effects of spray-drying process and acidic solvent system on physicochemical properties of chitosan salts were investigated. Chitosan used in spray dryings was obtained by deacetylation of chitin from lobster (Panulirus argus) origin. The chitosan acid salts were prepared in a laboratory-scale spray drier, and organic acetic acid, lactic acid, and citric acid were used as solvents in the process. The physicochemical properties of chitosan salts were investigated by means of solid-state CP...

  12. Selectivity of substrate binding and ionization of 2-methyl-3-hydroxypyridine-5-carboxylic acid oxygenase.

    Science.gov (United States)

    Luanloet, Thikumporn; Sucharitakul, Jeerus; Chaiyen, Pimchai

    2015-08-01

    2-Methyl-3-hydroxypyridine-5-carboxylic acid (MHPC) oxygenase (EC 1.14.12.4) from Pseudomonas sp. MA-1 is a flavin-dependent monooxygenase that catalyzes a hydroxylation and aromatic ring cleavage reaction. The functional roles of two residues, Tyr223 and Tyr82, located ~ 5 Å away from MHPC, were characterized using site-directed mutagenesis, along with ligand binding, product analysis and transient kinetic experiments. Mutation of Tyr223 resulted in enzyme variants that were impaired in their hydroxylation activity and had Kd values for substrate binding 5-10-fold greater than the wild-type enzyme. Because this residue is adjacent to the water molecule that is located next to the 3-hydroxy group of MHPC, the results indicate that the interaction between Tyr223, H2 O and the 3-hydroxyl group of MHPC are important for substrate binding and hydroxylation. By contrast, the Kd for substrate binding of Tyr82His and Tyr82Phe variants were similar to that of the wild-type enzyme. However, only ~ 40-50% of the substrate was hydroxylated in the reactions of both variants, whereas most of the substrate was hydroxylated in the wild-type enzyme reaction. In free solution, MHPC or 5-hydroxynicotinic acid exists in a mixture of monoanionic and tripolar ionic forms, whereas only the tripolar ionic form binds to the wild-type enzyme. The binding of tripolar ionic MHPC would allow efficient hydroxylation through an electrophilic aromatic substitution mechanism. For the Tyr82His and Tyr82Phe variants, both forms of substrates can bind to the enzymes, indicating that the mutation at Tyr82 abolished the selectivity of the enzyme towards the tripolar ionic form. Transient kinetic studies indicated that the hydroxylation rate constants of both Tyr82 variants are approximately two- to 2.5-fold higher than that of the wild-type enzyme. Altogether, our findings suggest that Tyr82 is important for the binding selectivity of MHPC oxygenase towards the tripolar ionic species, whereas the

  13. Difference between Extra- and Intracellular T1 Values of Carboxylic Acids Affects the Quantitative Analysis of Cellular Kinetics by Hyperpolarized NMR

    DEFF Research Database (Denmark)

    Karlsson, Magnus; Jensen, Pernille Rose; Ardenkjær-Larsen, Jan Henrik

    2016-01-01

    on the quantification of intracellular metabolicactivity. It is expected that the significantly shorter T1valueof the carboxylic moieties inside cells is a result of macro-molecular crowding. An artificial cytosol has been preparedand applied to predict the T1of other carboxylic acids. Wedemonstrate the value......Incomplete knowledge of the longitudinal relaxationtime constant (T1) leads to incorrect assumptions in quantita-tive kinetic models of cellular systems, studied by hyper-polarized real-time NMR. Using an assay that measures theintracellular signal of small carboxylic acids in living cells...

  14. Synthesis of new oxovanadium (IV) complexes of potential insulinmimetic activity with coumarin-3-carboxylic acid ligands and substituted derivatives

    International Nuclear Information System (INIS)

    Salas Fernandez, Paloma; Alvino de la Sota, Nora; Galli Rigo-Righi, Carla

    2013-01-01

    This work comprises the design and synthesis of four new oxovanadium (IV) complexes, a metal which possesses insulin-mimetic action. Coumarin-3-carboxylic acid and three of its 6 -and 6,8- derivatives were used as ligands. Coumarins are of interest due to their well-known biological properties and pharmacological applications; these include the insulino-sensibilizing effect of certain alcoxy-hydroxy-derivatives which might lead to the eventual existence of a synergetic effect with the active metal center. The synthesis of the vanadyl complexes was preceded by the synthesis of the coumarin-3-carboxylic acid and its 6-bromo- derivative, as well as the syntheses of three derivatives not previously reported: 6-bromo-8-metoxi-, 6-bromo-8-nitro-, and 6-bromo-8-hydroxy-, which were prepared by a Knoevenagel condensation reaction. The complexes, on their part, were prepared by a metathesis reaction between VOSO 4 and the corresponding ligands, on the basis of methods reported for other vanadyl complexes and under strict pH control. The coumarin-3-carboxylic ligands and the derivatives were characterized by 1 H-NMR-, FTIR- and UV-Vis-spectroscopy. In the case of the complexes, their paramagnetic character did not allow for NMR characterization, being thus identified by FT-IR-spectroscopy and by the quantitative determination of their vanadium contents. (author)

  15. The use of approximation formulae in calculations of acid-base equilibria-II: salts of mono- and diprotic acids.

    Science.gov (United States)

    Narasaki, H

    1980-02-01

    The pH of solutions of salts of mono- and diprotic acids is calculated by use of approximation formulae and the theoretically exact equations. The regions for useful application of the approximation formulae (error monoprotic acids, areas are symmetrically equal to those of the acids. For salts of diprotic acids the ranges generally depend on K(2)/K(1).

  16. Megasphaera hexanoica sp. nov., a medium-chain carboxylic acid-producing bacterium isolated from a cow rumen.

    Science.gov (United States)

    Jeon, Byoung Seung; Kim, Seil; Sang, Byoung-In

    2017-07-01

    Strain MHT, a strictly anaerobic, Gram-stain-negative, non-spore-forming, spherical coccus or coccoid-shaped microorganism, was isolated from a cow rumen during a screen for hexanoic acid-producing bacteria. The microorganism grew at 30-40 °C and pH 5.5-7.5 and exhibited production of various short- and medium-chain carboxylic acids (acetic acid, butyric acid, pentanoic acid, isobutyric acid, isovaleric acid, hexanoic acid, heptanoic acid and octanoic acid), as well as H2 and CO2 as biogas. Phylogenetic analysis based on 16S rRNA gene sequencing demonstrated that MHT represents a member of the genus Megasphaera, with the closest relatives being Megapsphaera indica NMBHI-10T (94.1 % 16S rRNA sequence similarity), Megasphaera elsdenii DSM 20460T (93.8 %) and Megasphaera paucivorans DSM 16981T (93.8 %). The major cellular fatty acids produced by MHT included C12 : 0, C16 : 0, C18 : 1cis 9, and C18 : 0, and the DNA G+C content of the MHT genome is 51.8 mol%. Together, the distinctive phenotypic and phylogenetic characteristics of MHT indicate that this microorganism represents a novel species of the genus Megasphaera, for which the name Megasphaera hexanoica sp. nov. is herein proposed. The type strain of this species is MHT (=KCCM 43214T=JCM 31403T).

  17. Synthesis and complexation properties towards uranyl cation of carboxylic acid derivatives of p-tert-butyl-calix[6]arene

    International Nuclear Information System (INIS)

    Souane, R.

    2005-03-01

    In the fuel reprocessing plants radioactive metals, and more particularly, uranium in UO 2 2+ form in the various installations, have many varied physico-chemical forms and there is a risk of exposure and internal contamination in the nuclear industry. It is necessary to exert a medical control to ensure the protection of the health of the workers. This medical control is done by dosing uranyl cation in the urine of the exposed people. This work forms part of this context. Indeed, we prepared a ligand able to complex the ion uranyl and which is also to be grafted on a solid support. In the family of calixarenes, the calix[6]arenes functionalized by three or four carboxylic functions were selected like chelating molecules of the ion uranyl. The properties of complexation of these calixarenes were studied by potentiometry in methanol, under these conditions balances of protonation and complexation were determined and the constant partners were obtained using the Hyperquad program. We synthesized tri-carboxylic calix[6]arenes comprising of the groupings nitro (NO 2 ) in para position of phenol in order to see the influence of a substitution in para position on the complexation. We also synthesized calix[6]arenes tetra-carboxylic in order to show the role of an additional carboxylic acid grouping. The potentiometric study determined thermodynamic parameters of protonation and complexation of carboxylic calix[6]arenes. The results of the complexation highlighted which complex UO 2 L corresponding to the ligand para-tert-butyl-calix[6]arene tetra-acid is more stable than that corresponding to the ligand mono-nitro calix[6]arene tri-acid (ΔlogΒ110 = 4.3), and than the effect of the groupings nitro in para position has low influence on the complexation of UO 2 2+ . This makes it possible to consider as possible the grafting of the calix[6]arenes which one knows the behaviour of trapping. To this end we synthesized the ligand 23. (author)

  18. Conductometric investigation of salt-free solutions of polyriboguanylic acid

    International Nuclear Information System (INIS)

    Kozlov, A.G.; Davydova, O.V.; Kargov, S.I.

    1993-01-01

    Salt-free solutions of various ionic forms of polyriboguanylic acid (poly(G)) were studied by the methods of conductometry and spectroscopy of annular dichroism. The Manning approach was employed to calculate transport characteristics and structural parameters of poly(G) on the basis of spectra permit putting poly(G) salts in two groups: the first one comprising NH 4 + -, Rb + -, K + -, Na + -, the second one - Cs + -, and Li + -poly(G). The assumption is made that Li + and Cs + ions, bound with concrete groups of polyanion in a specific way, can promote formation of a stable structure different from the one observed in the presence of the first group counterions. 25 refs., 3 figs

  19. Formation and High-order Carboxylic Acids (RCOOH) in Interstellar Analogous Ices of Carbon Dioxide (CO2) and Methane(CH4)

    Science.gov (United States)

    Zhu, Cheng; Turner, Andrew M.; Abplanalp, Matthew J.; Kaiser, Ralf I.

    2018-01-01

    This laboratory study simulated the abiotic formation of carboxylic acids (RCOOH) in interstellar analogous ices of carbon dioxide (CO2) and methane (CH4) at 10 K upon exposure to energetic electrons. The chemical processing of the ices and the subsequent warm-up phase were monitored online and in situ, exploiting Fourier Transform Infrared Spectrometry and quadrupole mass spectrometry. Characteristic absorptions of functional groups of carboxylic acids (RCOOH) were observed in the infrared spectra of the irradiated ice. Two proposed reaction mechanisms replicated the kinetic profiles of the carboxylic acids along with the decay profile of the precursors during the irradiation via hydrocarbon formation, followed by carboxylation and/or through acetic acid along with mass growth processes of the alkyl chain. Mass spectra recorded during the warm-up phase demonstrated that these acids are distributed from acetic acid (CH3COOH) up to decanoic acid (C9H19COOH). High-dose irradiation studies (91 ± 14 eV) converted low-molecular-weight acids such as acetic acid (CH3COOH) and propionic acid (C2H5COOH) to higher-molecular-weight carboxylic acids, compared to low-dose irradiation studies (18 ± 3 eV). The traces of the {{{H}}}2{{C}}= {{C}}({OH}{)}2+ (m/z = 60) fragment—a link to linear carboxylic acids—implied that higher-order acids (C n H2n+1COOH, n ≥ 5) are likely branched, which correlates with the recent analysis of the structures of the monocarboxylic acids in the Murchison meteorite.

  20. 78 FR 34338 - Citric Acid and Certain Citrate Salts From Canada: Preliminary Results of Antidumping Duty...

    Science.gov (United States)

    2013-06-07

    ... DEPARTMENT OF COMMERCE International Trade Administration [A-122-853] Citric Acid and Certain... on citric acid and certain citrate salts (citric acid) from Canada. The period of review (POR) is May... INFORMATION: Scope of the Order The merchandise covered by this order is citric acid and certain citrate salts...

  1. Rapid Screening of Carboxylic Acids from Waste and Surface Waters by ESI-MS/MS Using Barium Ion Chemistry and On-Line Membrane Sampling

    Science.gov (United States)

    Duncan, Kyle D.; Volmer, Dietrich A.; Gill, Chris G.; Krogh, Erik T.

    2016-03-01

    Negative ion tandem mass spectrometric analysis of aliphatic carboxylic acids often yields only non-diagnostic ([M - H]-) ions with limited selective fragmentation. However, carboxylates cationized with Ba2+ have demonstrated efficient dissociation in positive ion mode, providing structurally diagnostic product ions. We report the application of barium adducts followed by collision induced dissociation (CID), to improve selectivity for rapid screening of carboxylic acids in complex aqueous samples. The quantitative MS/MS method presented utilizes common product ions of [M - H + Ba]+ precursor ions. The mechanism of product ion formation is investigated using isotopically labeled standards and a series of structurally related carboxylic acids. The results suggest that hydrogen atoms in the β and γ positions yield common product ions ([BaH]+ and [BaOH]+). Furthermore, the diagnostic product ion at m/z 196 serves as a qualifying ion for carboxylate species. This methodology has been successfully used in conjunction with condensed phase membrane introduction mass spectrometry (CP-MIMS), with barium acetate added directly to the methanol acceptor phase. The combination enables rapid screening of carboxylic acids directly from acidified water samples (wastewater effluent, spiked natural waters) using a capillary hollow fiber PDMS membrane immersion probe. We have applied this technique for the direct analysis of complex naphthenic acid mixtures spiked into natural surface waters using CP-MIMS. Selectivity at the ionization and tandem mass spectrometry level eliminate isobaric interferences from hydroxylated species present within the samples, which have been observed in negative electrospray ionization.

  2. Rapid Screening of Carboxylic Acids from Waste and Surface Waters by ESI-MS/MS Using Barium Ion Chemistry and On-Line Membrane Sampling.

    Science.gov (United States)

    Duncan, Kyle D; Volmer, Dietrich A; Gill, Chris G; Krogh, Erik T

    2016-03-01

    Negative ion tandem mass spectrometric analysis of aliphatic carboxylic acids often yields only non-diagnostic ([M - H](-)) ions with limited selective fragmentation. However, carboxylates cationized with Ba(2+) have demonstrated efficient dissociation in positive ion mode, providing structurally diagnostic product ions. We report the application of barium adducts followed by collision induced dissociation (CID), to improve selectivity for rapid screening of carboxylic acids in complex aqueous samples. The quantitative MS/MS method presented utilizes common product ions of [M - H + Ba](+) precursor ions. The mechanism of product ion formation is investigated using isotopically labeled standards and a series of structurally related carboxylic acids. The results suggest that hydrogen atoms in the β and γ positions yield common product ions ([BaH](+) and [BaOH](+)). Furthermore, the diagnostic product ion at m/z 196 serves as a qualifying ion for carboxylate species. This methodology has been successfully used in conjunction with condensed phase membrane introduction mass spectrometry (CP-MIMS), with barium acetate added directly to the methanol acceptor phase. The combination enables rapid screening of carboxylic acids directly from acidified water samples (wastewater effluent, spiked natural waters) using a capillary hollow fiber PDMS membrane immersion probe. We have applied this technique for the direct analysis of complex naphthenic acid mixtures spiked into natural surface waters using CP-MIMS. Selectivity at the ionization and tandem mass spectrometry level eliminate isobaric interferences from hydroxylated species present within the samples, which have been observed in negative electrospray ionization.

  3. Exploring the reductive capacity of Pyrococcus furiosus : the reduction of carboxylic acids and pyridine nucleotides

    NARCIS (Netherlands)

    Ban, van den E.C.D.

    2001-01-01

    This Ph.D. project started in 1997 and its main goal was to obtain insight in the reductive capacity of the hyperthermophilic archaeon Pyrococcus furiosus . The research was focused on the biocatalytic reduction of carboxylic

  4. 1-Allyl-3-amino-1H-pyrazole-4-carboxylic acid

    Directory of Open Access Journals (Sweden)

    Feng-Ling Yang

    2008-12-01

    Full Text Available The title compound, C7H9N3O2, was prepared by alkaline hydrolysis of ethyl 1-allyl-3-amino-1H-pyrazole-4-carboxylate. The crystal structure is stabilized by three types of intermolecular hydrogen bond (N—H...O, N—H...N and O—H...N.

  5. Acid-base-controlled stereoselective metalation of overhanging carboxylic acid porphyrins: consequences for the formation of heterobimetallic complexes.

    Science.gov (United States)

    Le Gac, Stéphane; Najjari, Btissam; Dorcet, Vincent; Roisnel, Thierry; Fusaro, Luca; Luhmer, Michel; Furet, Eric; Halet, Jean-François; Boitrel, Bernard

    2013-08-12

    Overhanging carboxylic acid porphyrins have revealed promising ditopic ligands offering a new entry in the field of supramolecular coordination chemistry of porphyrinoids. Notably, the adjunction of a so-called hanging-atop (HAT) Pb(II) cation to regular Pb(II) porphyrin complexes allowed a stereoselective incorporation of the N-core bound cation, and an allosterically controlled Newton's cradle-like motion of the two Pb(II) ions also emerged from such bimetallic complexes. In this contribution, we have extended this work to other ligands and metal ions, aiming at understanding the parameters that control the HAT Pb(II) coordination. The nature of the N-core bound metal ion (Zn(II), Cd(II)), the influence of the deprotonation state of the overhanging COOH group and the presence of a neutral ligand on the opposite side (exogenous or intramolecular), have been examined through (1)H NMR spectroscopic experiments with the help of radiocrystallographic structures and DFT calculations. Single and bis-strap ligands have been considered. They all incorporate a COOH group hung over the N-core on one side. For the bis-strap ligands, either an ester or an amide group has been introduced on the other side. In the presence of a base, the mononuclear Zn(II) or Cd(II) complexes incorporate the carbonyl of the overhanging carboxylate as apical ligand, decreasing its availability for the binding of a HAT Pb(II). An allosteric effector (e.g., 4-dimethylaminopyridine (DMAP), in the case of a single-strap ligand) or an intramolecular ligand (e.g., an amide group), strong enough to compete with the carbonyl of the hung COO(-), is required to switch the N-core bound cation to the opposite side with concomitant release of the COO(-), thereby allowing HAT Pb(II) complexation. In the absence of a base, Zn(II) or Cd(II) binds preferentially the carbonyl of the intramolecular ester or amide groups in apical position rather than that of the COOH. This better preorganization, with the

  6. Effect of inorganic salts on the volatility of organic acids.

    Science.gov (United States)

    Häkkinen, Silja A K; McNeill, V Faye; Riipinen, Ilona

    2014-12-02

    Particulate phase reactions between organic and inorganic compounds may significantly alter aerosol chemical properties, for example, by suppressing particle volatility. Here, chemical processing upon drying of aerosols comprised of organic (acetic, oxalic, succinic, or citric) acid/monovalent inorganic salt mixtures was assessed by measuring the evaporation of the organic acid molecules from the mixture using a novel approach combining a chemical ionization mass spectrometer coupled with a heated flow tube inlet (TPD-CIMS) with kinetic model calculations. For reference, the volatility, i.e. saturation vapor pressure and vaporization enthalpy, of the pure succinic and oxalic acids was also determined and found to be in agreement with previous literature. Comparison between the kinetic model and experimental data suggests significant particle phase processing forming low-volatility material such as organic salts. The results were similar for both ammonium sulfate and sodium chloride mixtures, and relatively more processing was observed with low initial aerosol organic molar fractions. The magnitude of low-volatility organic material formation at an atmospherically relevant pH range indicates that the observed phenomenon is not only significant in laboratory conditions but is also of direct atmospheric relevance.

  7. Indium-Catalyzed Reductive Dithioacetalization of Carboxylic Acids with Dithiols: Scope, Limitations, and Application to Oxidative Desulfurization.

    Science.gov (United States)

    Nishino, Kota; Minato, Kohei; Miyazaki, Takahiro; Ogiwara, Yohei; Sakai, Norio

    2017-04-07

    In this study an InI 3 -TMDS (1,1,3,3-tetramethyldisiloxane) reducing system effectively catalyzed the reductive dithioacetalization of a variety of aromatic and aliphatic carboxylic acids with 1,2-ethanedithiol or 1,3-propanedithiol leading to the one-pot preparation of either 1,3-dithiolane derivatives or a 1,3-dithiane derivative. Also, the intact indium catalyst continuously catalyzed the subsequent oxidative desulfurization of an in situ formed 1,3-dithiolane derivative, which led to the preparation of the corresponding aldehydes.

  8. 4-Hydroxy-3-methyl-6-phenylbenzofuran-2-carboxylic acid ethyl ester derivatives as potent anti-tumor agents.

    Science.gov (United States)

    Hayakawa, Ichiro; Shioya, Rieko; Agatsuma, Toshinori; Furukawa, Hidehiko; Naruto, Shunji; Sugano, Yuichi

    2004-01-19

    Based on the structure of 4-hydroxy-3-methyl-6-phenylbenzofuran-2-carboxylic acid ethyl ester (1), which exhibits selective cytotoxicity against a tumorigenic cell line, (2,4-dimethoxyphenyl)-(4-hydroxy-3-methyl-6-phenylbenzofuran-2-yl)-methanone (18m) was designed and synthesized as a biologically stable derivative containing no ester group. Although the potency of 18m was almost the same as our initial hit compound 1, 18m is expected to last longer in the human body as an anticancer agent.

  9. Study of the electronic structure at the interface between fluorene-1-carboxylic acid molecules and Cu(110)

    International Nuclear Information System (INIS)

    Song Fei; Mao Hongying; Guan Dandan; Dou Weidong; Zhang Hanjie; Li Haiyang; He Pimo; Bao Shining; Hofmann, Philip

    2009-01-01

    The interface electronic properties of fluorene-1-carboxylic acid (FC-1) adsorbed on Cu(110) have been studied by ultraviolet photoemission spectroscopy (UPS) and first-principles calculations. Both the molecular orbitals and the Cu valence band are significantly modified upon adsorption. FC-1 is chemically bonded to Cu(110) through charge donation and back donation involving the lowest unoccupied molecular orbital (LUMO) and the highest occupied molecular orbital (HOMO) of the molecule. An observed reduction of the work function can be attributed to the adsorption induced charge redistribution, and the positive interface dipole.

  10. An enantioselective approach toward 3,4-dihydroisocoumarin through the bromocyclization of styrene-type carboxylic acids.

    Science.gov (United States)

    Chen, Jie; Zhou, Ling; Tan, Chong Kiat; Yeung, Ying-Yeung

    2012-01-20

    A facile and enantioselective approach toward 3,4-dihydroisocoumarin was developed. The method involved an amino-thiocarbamate catalyzed enantioselective bromocyclization of styrene-type carboxylic acids, yielding 3-bromo-3,4-dihydroisocoumarins with good yields and ee's. 3-Bromo-3,4-dihydroisocoumarins are versatile building blocks for various dihydroisocoumarin derivatives in which the Br group can readily be modified to achieve biologically important 4-O-type and 4-N-type 3,4-dihydroisocoumarin systems. In addition, studies indicated that, by refining some parameters, the synthetically useful 5-exo phthalide products could be achieved with good yields and ee's.

  11. Surface properties of calcium and magnesium oxide nanopowders grafted with unsaturated carboxylic acids studied with inverse gas chromatography.

    Science.gov (United States)

    Maciejewska, Magdalena; Krzywania-Kaliszewska, Alicja; Zaborski, Marian

    2012-09-28

    Inverse gas chromatography (IGC) was applied at infinite dilution to evaluate the surface properties of calcium and magnesium oxide nanoparticles and the effect of surface grafted unsaturated carboxylic acid on the nanopowder donor-acceptor characteristics. The dispersive components (γ(s)(D)) of the free energy of the nanopowders were determined by Gray's method, whereas their tendency to undergo specific interactions was estimated based on the electron donor-acceptor approach presented by Papirer. The calcium and magnesium oxide nanoparticles exhibited high surface energies (79 mJ/m² and 74 mJ/m², respectively). Modification of nanopowders with unsaturated carboxylic acids decreased their specific adsorption energy. The lowest value of γ(s)(D) was determined for nanopowders grafted with undecylenic acid, approximately 55 mJ/m². The specific interactions were characterised by the molar free energy (ΔG(A)(SP)) and molar enthalpy (ΔH(A)(SP)) of adsorption as well as the donor and acceptor interaction parameters (K(A), K(D)). Copyright © 2012 Elsevier B.V. All rights reserved.

  12. Source indicators of biomass burning associated with inorganic salts and carboxylates in dry season ambient aerosol in Chiang Mai Basin, Thailand

    Science.gov (United States)

    Tsai, Ying I.; Sopajaree, Khajornsak; Chotruksa, Auranee; Wu, Hsin-Ching; Kuo, Su-Ching

    2013-10-01

    PM10 aerosol was collected between February and April 2010 at an urban site (CMU) and an industrial site (TOT) in Chiang Mai, Thailand, and characteristics and provenance of water-soluble inorganic species, carboxylates, anhydrosugars and sugar alcohols were investigated with particular reference to air quality, framed as episodic or non-episodic pollution. Sulfate, a product of secondary photochemical reactions, was the major inorganic salt in PM10, comprising 25.9% and 22.3% of inorganic species at CMU and TOT, respectively. Acetate was the most abundant monocarboxylate, followed by formate. Oxalate was the dominant dicarboxylate. A high acetate/formate mass ratio indicated that primary traffic-related and biomass-burning emissions contributed to Chiang Mai aerosols during episodic and non-episodic pollution. During episodic pollution carboxylate peaks indicated sourcing from photochemical reactions and/or directly from traffic-related and biomass burning processes and concentrations of specific biomarkers of biomass burning including water-soluble potassium, glutarate, oxalate and levoglucosan dramatically increased. Levoglucosan, the dominant anhydrosugar, was highly associated with water-soluble potassium (r = 0.75-0.79) and accounted for 93.4% and 93.7% of anhydrosugars at CMU and TOT, respectively, during episodic pollution. Moreover, levoglucosan during episodic pollution was 14.2-21.8 times non-episodic lows, showing clearly that emissions from biomass burning are the major cause of PM10 episodic pollution in Chiang Mai. Additionally, the average levoglucosan/mannosan mass ratio during episodic pollution was 14.1-14.9, higher than the 5.73-7.69 during non-episodic pollution, indicating that there was more hardwood burning during episodic pollution. Higher concentrations of glycerol and erythritol during episodic pollution further indicate that biomass burning activities released soil biota from forest and farmland soils.

  13. Transepithelial transport of aliphatic carboxylic acids studied in Madin Darby canine kidney (MDCK) cell monolayers

    International Nuclear Information System (INIS)

    Cho, M.J.; Adson, A.; Kezdy, F.J.

    1990-01-01

    Transport of 14C-labeled acetic, propionic (PA), butyric, valeric, heptanoic (HA), and octanoic (OA) acids across the Madin Darby canine kidney (MDCK) epithelial cell monolayer grown on a porous polycarbonate membrane was studied in Hanks' balanced salt solution (HBSS) at 37 degrees C in both apical-to-basolateral and basolateral-to-apical directions. At micromolar concentrations of solutes, metabolic decomposition was significant as evidenced by [14C]CO2 production during the OA transport. The apparent permeability (Pe) indicates that as lipophilicity increases, diffusion across the unstirred boundary layer becomes rate limiting. In support of this notion, transport of OA and HA was enhanced by agitation, showed an activation energy of 3.7 kcal/mol for OA, and resulted in identical Pe values for both transport directions. Analysis of Pe changes with varying alkyl chain length resulted in a delta G of -0.68 +/- 0.09 kcal/mol for -CH2-group transfer from an aqueous phase to the MDCK cells. When the intercellular tight junctions were opened by the divalent chelator EGTA in Ca2+/Mg2(+)-free HBSS, transport of the fluid-phase marker Lucifer yellow greatly increased because of paracellular leakage. PA transport also showed a significant increase, but OA transport was independent of EGTA. Although albumin also undergoes paracellular transport in the presence of EGTA and OA binds strongly to albumin, OA transport in EGTA solution was unchanged by albumin. These observations indicate that transmembrane transport is the major mechanism for lipophilic substances. The present study, together with earlier work on the transport of polar substances, shows that the MDCK cell monolayer is an excellent model of the transepithelial transport barrier

  14. Enhancement of electroluminescence in zirconium poly carboxylic acid-based light emitting diodes by bathophenanthroline ligand.

    Science.gov (United States)

    Shahroosvand, Hashem; Nasouti, Fahimeh; Sousaraei, Ahmad; Mohajerani, Ezeddin; Khabbazi, Amir

    2013-06-28

    The reactions of a zirconium salt with 1,2,4,5-benzenetetracarboxylate (btec), bathophenanthroline (Bphen) and thiocyanate ions were synthesized and studied by changing the mole ratio, the order of reactant and their pH. It is found that the coordination mode of btec acid depends on the control of reaction conditions. Monodentate, bidentate and bridging modes were investigated by FT-IR spectroscopy. The structures of Zr(btec) and Zr(btec)(Bphen) complexes were also characterized by UV-Vis, CHN, ICP-AES, (1)H NMR and cyclic voltammetry. The role of Bphen ligand in the photopysical properties of Zr(btec)(Bphen) complexes was investigated by DFT calculation. The photoluminescence (PL) emission of nine Zr(btec) complexes that have two peaks, a sharp and intense band for the first peak from 320 to 430 nm in comparison to the second peak with a less intensity and broadened in the regions of 650-780 nm. PL spectra of twelve Zr(btec)(Bphen) complexes also showed bands at 450, 550, 625 nm. LED devices with Zr complex as emitter layer and the structure ITO/PEDOT:PSS/PVK:PBD/zirconium complex/Al emitted a broad band centered at 550 and 650 originating from the Zr complexes. The EL spectra of Zr(btec) and Zr(btec)(Bphen) complexes indicated a long red shift rather than PVK:PBD blend. We believe that the electroplex occurring at PVK-Zr complexes interface is responsible for the green-red emission in the EL of the device. These observations suggest an important role for the Bphen ligand to improve EL performance.

  15. A rapid microwave induced synthesis of [carboxyl-14C]-nicotinic acid (vitamin B3) and [carbonyl-14C]-nicotinamide using K14CN

    International Nuclear Information System (INIS)

    Ravi, S.; Mathew, K.M.; Sivaprasad, N.

    2008-01-01

    Microwave assisted direct aromatic substitution of 3-bromopyridine with K 14 CN as the cyanide source and catalytic amount of tetrabutylammonium bromide afforded [3- 14 C]-cyanopyridine 3 in 90% yield. Microwave assisted hydrolysis of 3 with a mixture of concentrated hydrochloric acid and propionic acid afforded [carboxyl- 14 C]-nicotinic acid in 95% yield whereas microwave assisted hydrolysis of 3 with a mixture of concentrated sulfuric acid and propionic acid afforded [carbonyl- 14 C]-nicotinamide in 85% yield. (author)

  16. Alleviation of salt stress in lemongrass by salicylic acid.

    Science.gov (United States)

    Idrees, Mohd; Naeem, M; Khan, M Nasir; Aftab, Tariq; Khan, M Masroor A; Moinuddin

    2012-07-01

    Soil salinity is one of the key factors adversely affecting the growth, yield, and quality of crops. A pot study was conducted to find out whether exogenous application of salicylic acid could ameliorate the adverse effect of salinity in lemongrass (Cymbopogon flexuosus Steud. Wats.). Two Cymbopogon varieties, Krishna and Neema, were used in the study. Three salinity levels, viz, 50, 100, and 150 mM of NaCl, were applied to 30-day-old plants. Salicylic acid (SA) was applied as foliar spray at 10(-5) M concentration. Totally, six SA-sprays were carried out at 10-day intervals, following the first spray at 30 days after sowing. The growth parameters were progressively reduced with the increase in salinity level; however, growth inhibition was significantly reduced by the foliar application of SA. With the increase in salt stress, a gradual decrease in the activities of carbonic anhydrase and nitrate reductase was observed in both the varieties. SA-treatment not only ameliorated the adverse effects of NaCl but also showed a significant improvement in the activities of these enzymes compared with the untreated stressed-plants. The plants supplemented with NaCl exhibited a significant increase in electrolyte leakage, proline content, and phosphoenol pyruvate carboxylase activity. Content and yield of essential oil was also significantly decreased in plants that received salinity levels; however, SA overcame the unfavorable effects of salinity stress to a considerable extent. Lemongrass variety Krishna was found to be more adapted to salt stress than Neema, as indicated by the overall performance of the two varieties under salt conditions.

  17. Two-dimensional hydrogen-bonded polymers in the crystal structures of the ammonium salts of phenoxyacetic acid, (4-fluorophenoxyacetic acid and (4-chloro-2-methylphenoxyacetic acid

    Directory of Open Access Journals (Sweden)

    Graham Smith

    2014-12-01

    Full Text Available The structures of the ammonium salts of phenoxyacetic acid, NH4+·C8H6O3−, (I, (4-fluorophenoxyacetic acid, NH4+·C8H5FO3−, (II, and the herbicidally active (4-chloro-2-methylphenoxyacetic acid (MCPA, NH4+·C9H8ClO3−·0.5H2O, (III have been determined. All have two-dimensional layered structures based on inter-species ammonium N—H...O hydrogen-bonding associations, which give core substructures consisting primarily of conjoined cyclic motifs. The crystals of (I and (II are isomorphous with the core comprising R12(5, R12(4 and centrosymmetric R42(8 ring motifs, giving two-dimensional layers lying parallel to (100. In (III, the water molecule of solvation lies on a crystallographic twofold rotation axis and bridges two carboxyl O atoms in an R44(12 hydrogen-bonded motif, creating two R43(10 rings, which together with a conjoined centrosymmetric R42(8 ring incorporating both ammonium cations, generate two-dimensional layers lying parallel to (100. No π–π ring associations are present in any of the structures.

  18. 40 CFR 721.2098 - Aliphatic polycarboxylic acid metal salt (generic).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Aliphatic polycarboxylic acid metal... Specific Chemical Substances § 721.2098 Aliphatic polycarboxylic acid metal salt (generic). (a) Chemical... as an aliphatic polycarboxylic acid metal salt (PMN P-01-7) is subject to reporting under this...

  19. 40 CFR 721.10098 - Disubstituted benzoic acid, alkali metal salt (generic).

    Science.gov (United States)

    2010-07-01

    ... New Uses for Specific Chemical Substances § 721.10098 Disubstituted benzoic acid, alkali metal salt... identified generically as disubstituted benzoic acid, alkali metal salt (PMN P-03-643) is subject to... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Disubstituted benzoic acid, alkali...

  20. 40 CFR 721.720 - Alkoxylated fatty acid amide, alkylsulfate salt.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Alkoxylated fatty acid amide... Specific Chemical Substances § 721.720 Alkoxylated fatty acid amide, alkylsulfate salt. (a) Chemical... as an alkoxylated fatty acid amide, alkylsulfate salt (PMN P-97-136) is subject to reporting under...

  1. 40 CFR 721.3032 - Boric acid (H3BO2), zinc salt.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Boric acid (H3BO2), zinc salt. 721... Substances § 721.3032 Boric acid (H3BO2), zinc salt. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as boric acid (H3BO2), zinc salt (PMN P-97-553...

  2. Additional Nucleophile-Free FeCl3-Catalyzed Green Deprotection of 2,4-Dimethoxyphenylmethyl-Protected Alcohols and Carboxylic Acids.

    Science.gov (United States)

    Sawama, Yoshinari; Masuda, Masahiro; Honda, Akie; Yokoyama, Hiroki; Park, Kwihwan; Yasukawa, Naoki; Monguchi, Yasunari; Sajiki, Hironao

    2016-01-01

    The deprotection of the methoxyphenylmethyl (MPM) ether and ester derivatives can be generally achieved by the combinatorial use of a catalytic Lewis acid and stoichiometric nucleophile. The deprotections of 2,4-dimethoxyphenylmethyl (DMPM)-protected alcohols and carboxylic acids were found to be effectively catalyzed by iron(III) chloride without any additional nucleophile to form the deprotected mother alcohols and carboxylic acids in excellent yields. Since the present deprotection proceeds via the self-assembling mechanism of the 2,4-DMPM protective group itself to give the hardly-soluble resorcinarene derivative as a precipitate, the rigorous purification process by silica-gel column chromatography was unnecessary and the sufficiently-pure alcohols and carboxylic acids were easily obtained in satisfactory yields after simple filtration.

  3. Effect of a Long Chain Carboxylate Acid on Sodium Dodecyl Sulfate Micelle Structure: A Small-angle Neutron Scattering Study

    International Nuclear Information System (INIS)

    Arum Patriati; Edy Giri Rachman Putra

    2009-01-01

    The effect of different hydrocarbon chain length of carboxylate acid, i.e. dodecanoic acid, CH 3 (CH 2 ) 10 COOH and hexadecanoic acid, CH 3 (CH 2 ) 14 COOH as a co-surfactant in the 0.3M SDS micellar solution has been studied using small angle neutron scattering (SANS). Here, the present of dodecanoic acid has induced the SDS structural micelles. The ellipsoid micelles structures changed significantly in length (major axis) from 21.7 Armstrong to 35.5 Armstrong at a fixed minor axis of 16.7 Armstrong in the present of 0.005M to 0.1M dodecanoic acid. Nevertheless, this effect was not shown in the present of hexadecanoic acid with the same concentration range. The present of hexadecanoic acid molecules gave a small effect on growth of SDS micelles where the major axis of the micelle was simply elongated from 21.5 Armstrong to 23.5 Armstrong. It showed that the appropriate hydrocarbon chain length between surfactant and co-surfactant molecules is one of the determining factors in forming a mixed micelles structure. (author)

  4. Copolymers Based on Indole-6-Carboxylic Acid and 3,4-Ethylenedioxythiophene as Platinum Catalyst Support for Methanol Oxidation

    Directory of Open Access Journals (Sweden)

    Tzi-Yi Wu

    2015-10-01

    Full Text Available Indole-6-carboxylic acid (ICA and 3,4-ethylenedioxythiophene (EDOT are copolymerized electrochemically on a stainless steel (SS electrode to obtain poly(indole-6-carboxylic acid-co-3,4-ethylenedioxythiophenes (P(ICA-co-EDOTs. The morphology of P(ICA-co-EDOTs is checked using scanning electron microscopy (SEM, and the SEM images reveal that these films are composed of highly porous fibers when the feed molar ratio of ICA/EDOT is greater than 3/2. Platinum particles can be electrochemically deposited into the P(ICA-co-EDOTs and PICA films to obtain P(ICA-co-EDOTs-Pt and PICA-Pt composite electrodes, respectively. These composite electrodes are further characterized using X-ray photoelectron spectroscopy (XPS, SEM, X-ray diffraction analysis (XRD, and cyclic voltammetry (CV. The SEM result indicates that Pt particles disperse more uniformly into the highly porous P(ICA3-co-EDOT2 fibers (feed molar ratio of ICA/EDOT = 3/2. The P(ICA3-co-EDOT2-Pt nanocomposite electrode exhibited excellent catalytic activity for the electrooxidation of methanol in these electrodes, which reveals that P(ICA3-co-EDOT2-Pt nanocomposite electrodes are more promising for application in an electrocatalyst as a support material.

  5. Chemo-enzymatic Baeyer-Villiger oxidation of 4-methylcyclohexanone via kinetic resolution of racemic carboxylic acids: direct access to enantioenriched lactone.

    Science.gov (United States)

    Drożdż, Agnieszka; Chrobok, Anna

    2016-01-21

    A new method for the asymmetric chemo-enzymatic Baeyer-Villiger oxidation of prochiral 4-methylcyclohexanone to (R)-4-methylcaprolactone in the presence of (±)-4-methyloctanoic acid, Candida Antarctica lipase B and 30% aq. H2O2 has been developed. A mechanism for the asymmetric induction based on kinetic resolution of racemic carboxylic acids is proposed.

  6. Preparation of High-purity Indium Oxalate Salt from Indium Scrap by Organic Acids

    International Nuclear Information System (INIS)

    Koo, Su-Jin; Ju, Chang-Sik

    2013-01-01

    Effect of organic acid on the preparation of indium-oxalate salt from indium scraps generated from ITO glass manufacturing process was studied. Effects of parameters, such as type and concentration of organic acids, pH of reactant, temperature, reaction time on indium-oxalate salt preparation were examined. The impurity removal efficiency was similar for both oxalic acid and citric acid, but citric acid did not make organic acid salt with indium. The optimum conditions were 1.5 M oxalic acid, pH 7, 80 .deg. C, and 6 hours. On the other hand, the recoveries increased with pH, but the purity decreased. The indium-oxalate salt purity prepared by two cycles was 99.995% (4N5). The indium-oxalate salt could be converted to indium oxide and indium metal by substitution reaction and calcination

  7. Iron intake by rats using peroral administration of /sup 55/Fe-salts of phosphatidic acids

    Energy Technology Data Exchange (ETDEWEB)

    Rauch, P.; Kas, J. (Inst. of Chemical Technology, Prague (Czechoslovakia)); Tykva, R. (Ceskoslovenska Akademie Ved, Prague. Ustav Organicke Chemie a Biochemie)

    1984-03-15

    The utilization of /sup 55/Fe and its incorporation into rat organs was investigated after peroral administration of various salts of phosphatidic acids (PA). Iron of PA salts is utilized up to 58-94% comparing to /sup 55/Fe/sup 2 +/. The degree of iron utilization depends on the type of PA salts administered. 16 refs.

  8. Catalytic Conversion of Dihydroxyacetone to Lactic Acid Using Metal Salts in Water

    NARCIS (Netherlands)

    Rasrendra, Carolus B.; Fachri, Boy A.; Makertihartha, I. Gusti B. N.; Adisasmito, Sanggono; Heeres, Hero J.

    2011-01-01

    We herein present a study on the application of homogeneous catalysts in the form of metal salts on the conversion of trioses, such as dihydroxyacetone (DHA), and glyceraldehyde (GLY) to lactic acid (LA) in water. A wide range of metal salts (26 in total) were examined. Al(III) salts were identified

  9. Pancreatic adenocarcinoma, chronic pancreatitis, and MODY-8 diabetes: is bile salt-dependent lipase (or carboxyl ester lipase) at the crossroads of pancreatic pathologies?

    Science.gov (United States)

    Lombardo, Dominique; Silvy, Françoise; Crenon, Isabelle; Martinez, Emmanuelle; Collignon, Aurélie; Beraud, Evelyne; Mas, Eric

    2018-02-23

    Pancreatic adenocarcinomas and diabetes mellitus are responsible for the deaths of around two million people each year worldwide. Patients with chronic pancreatitis do not die directly of this disease, except where the pathology is hereditary. Much current literature supports the involvement of bile salt-dependent lipase (BSDL), also known as carboxyl ester lipase (CEL), in the pathophysiology of these pancreatic diseases. The purpose of this review is to shed light on connections between chronic pancreatitis, diabetes, and pancreatic adenocarcinomas by gaining an insight into BSDL and its variants. This enzyme is normally secreted by the exocrine pancreas, and is diverted within the intestinal lumen to participate in the hydrolysis of dietary lipids. However, BSDL is also expressed by other cells and tissues, where it participates in lipid homeostasis. Variants of BSDL resulting from germline and/or somatic mutations (nucleotide insertion/deletion or nonallelic homologous recombination) are expressed in the pancreas of patients with pancreatic pathologies such as chronic pancreatitis, MODY-8, and pancreatic adenocarcinomas. We discuss the possible link between the expression of BSDL variants and these dramatic pancreatic pathologies, putting forward the suggestion that BSDL and its variants are implicated in the cell lipid metabolism/reprogramming that leads to the dyslipidemia observed in chronic pancreatitis, MODY-8, and pancreatic adenocarcinomas. We also propose potential strategies for translation to therapeutic applications.

  10. HIGH YIELD AND RAPID SYNTHESES METHODS FOR PRODUCING METALLO-ORGANIC SALTS

    DEFF Research Database (Denmark)

    2005-01-01

    A new method for preparing salts of metal cations and organic acids, especially divalent salts of alkaline earth metal ions from group II of the periodic system and carboxylic acids. The method comprising the use of a high temperature (about 90° or more) and, optionally. high pressure, in order...... to obtain a higher yield, purity and faster reaction speed than obtained with known synthesis methods. In particular, the present invention relates to the production of strontium salts of carboxylic acids. Novel strontium salts are also provided by the present method....

  11. Zeolite-catalysed preparation of alpha-hydroxy carboxylic acids and esters thereof

    DEFF Research Database (Denmark)

    2010-01-01

    A process for the production of lactic acid and 2-hydroxy-3-butenoic acid or esters thereof by conversion of glucose, fructose, sucrose, xylose and glycolaldehyde dissolved in a solvent in presence of a solid Lewis acidic catalyst.......A process for the production of lactic acid and 2-hydroxy-3-butenoic acid or esters thereof by conversion of glucose, fructose, sucrose, xylose and glycolaldehyde dissolved in a solvent in presence of a solid Lewis acidic catalyst....

  12. Two luminescent frameworks constructed from lead(II) salts with carboxylate ligands containing dinuclear lead(II) units

    International Nuclear Information System (INIS)

    Zhu Xiandong; Li Xiaoju; Liu Qingyan; Lue Jian; Guo Zhengang; He Jinrun; Li Yafeng; Cao Rong

    2007-01-01

    Two luminescent Pb(II) coordination frameworks containing dinuclear lead(II) units, [Pb(PYDC)(H 2 O)] n (1) and [Pb(HPHT)] n (2) have been prepared by the self-assembly of lead(II) salts with pyridinecarboxylate and benzenecarboxylate. Single-crystal X-ray diffraction analyses reveal that compound 1 is a three-dimensional architecture consisting of Pb 2 O 2 dimeric building units, whereas compound 2 is a two-dimensional layer structure containing one-dimensional lead-oxide chains. The luminescent properties of 1 and 2 have been investigated in the solid state at room temperature, indicating structure-dependent photoluminescent properties of the coordination frameworks. - Graphical abstract: Two luminescent Pb(II) coordination frameworks, [Pb(PYDC)(H 2 O)] n (1) and [Pb(HPHT)] n (2) have been prepared. Single-crystal analyses reveal that compound 1 is a three-dimensional architecture consisting of Pb 2 O 2 dimeric building units, whereas compound 2 is a two-dimensional layer structure containing one-dimensional lead-oxide chains. The luminescent properties have been investigated, indicating structure-dependent photoluminescent properties of the coordination frameworks

  13. Perfluorinated carboxylic and sulphonic acids in surface water media from the regions of Tibetan Plateau: Indirect evidence on photochemical degradation?

    Science.gov (United States)

    Yamazaki, Eriko; Falandysz, Jerzy; Taniyasu, Sachi; Hui, Ge; Jurkiewicz, Gabriela; Yamashita, Nobuyoshi; Yang, Yong-Liang; Lam, Paul K S

    2016-01-01

    Perfluorinated surfactants and repellents are synthetic substances that have found numerous industrial and customer applications. Due to their persistence, at least two groups of these substances-perfluorinated carboxylic acids (PFCAs) and perfluorinated sulfonic acids (PFSAs)-are diffused widely in the environment. It is hypothesized that the Tibetan Plateau, is one of few unique places on the Earth, due to its topography, specifically the vast space and high elevation above sea level, geographic location, climate, high solar radiation, lack of industry, little urbanization and general lack of significant direct sources of pollution. There it is believed possible to gain an insight into atmospheric fate (possible photochemical degradation of higher molecular mass and formation of lower molecular mass PFCAs and PFSAs) of PFASs under un-disturbed environmental conditions. Ultratrace analytical method for PFCAs and PFSAs and use of transportation and field blanks, laboratory blanks and isotopically labelled surrogates for recovery control has allowed the determination of nine perfluorinated carboxylic acids and six perfluorinated sulfonic acids at ultra-trace levels in water based samples from the alpine dimension regions of the Tibetan Plateau, the eastern slope of Minya Konka peak at the eastern edge of the Tibetan Plateau, and also from the city of Chengdu from the lowland of the Sichuan Province in China. The specific compositional pattern of PFCAs and PFSAs and low levels of pollution with those compounds were observed in the central region of the Tibetan Plateau and in the region adjacent to the peaks of Minya Konka in the Eastern Tibetan Plateau. The fingerprint of the compositional pattern of PFCAs and PFSAs in water samples in the central region of the Tibetan Plateau and in the alpine region adjacent to the peaks of Minya Konka in the Eastern Tibetan Plateau may be explained by the result of photochemical degradation with dealkylation of longer chain

  14. Ultrasonic-assisted preparation of graphene oxide carboxylic acid polyvinyl alcohol polymer film and studies of thermal stability and surface resistivity.

    Science.gov (United States)

    Li, Yongshen; Li, Jihui; Li, Yuehai; Li, Yali; Song, Yunan; Niu, Shuai; Li, Ning

    2018-01-01

    In this paper, flake graphite, nitric acid and acetic anhydride are used to prepare graphene oxide carboxylic acid (GO-COOH) via an ultrasonic-assisted method, and GO-COOH and polyvinyl alcohol polymer (PVA) are used to synthesize graphene oxide carboxylic acid polyvinyl alcohol polymer (GO-COOPVA) via the ultrasonic-assisted method, and GO-COOPVA is used to manufacture graphene oxide carboxylic acid polyvinyl alcohol polymer film (GO-COOPVA film) via a solidification method, and the structure and morphology of GO-COOH, GO-COOPVA and GO-COOPVA film are characterized, and the thermal stability and surface resistivity are measured in the case of the different amount of GO-COOH. Based on the characterization and measurement, it has been successively confirmed and attested that carboxyl groups implant on 2D lattice of GO to form GO-COOH, and GO-COOH and PVA have the esterification reaction to produce GO-COOPVA, and GO-COOPVA consists of 2D lattice of GO-COOH and the chain of PVA connected in the form of carboxylic ester, and GO-COOPVA film is composed of GO-COOPVA, and the thermal stability of GO-COOPVA film obviously improves in comparison with PVA film, and the surface resistivity of GO-COOPVA film clearly decreases. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Enhancing Skin Permeation of Biphenylacetic Acid (BPA) Using Salt Formation with Organic and Alkali Metal Bases

    OpenAIRE

    PAWAR, Vijay; NAIK, Prashant; GIRIDHAR, Rajani; YADAV, Mange Ram

    2014-01-01

    In the present study, a series of organic and alkali metal salts of biphenylacetic acid (BPA) have been prepared and evaluated in vitro for percutaneous drug delivery. The physicochemical properties of BPA salts were determined using solubility measurements, DSC, and IR. The DSC thermogram and FTIR spectra confirmed the salt formation with organic and alkali metal bases. Among the series, salts with organic amines (ethanolamine, diethanolamine, triethanol-amine, and diethylamine) had lowered ...

  16. Analysis of carboxylate coordination function of the isomeric lanthanide pyridinedicarboxylates by means of vibration spectroscopy

    International Nuclear Information System (INIS)

    Puntus, L.; Zolin, V.; Kudryashova, V.

    2004-01-01

    The investigation of IR spectra of salts of six isomers of pyridinedicarboxylic acid (PDA): 2,3-, 2,4-, 2,5-, 2,6-, 3,4- and 3,5-pyridinedicarboxylic acids, have demonstrated that properties of these salts are dependent on the bonding manner of carboxylate groups and on coordination of heterocyclic nitrogen atom. The most prominent differences in properties and spectra of 2,6- and 3,4-PDA salts are conditioned correspondingly by monodentate and bidentate coordination functions of the carboxylate groups in these compounds. The correlation of the breathing vibration frequency, reflecting the rigidity of the heterocyclic ring, with position of the carboxylate substituents, conditioning intramolecular charge transfer (CT), was postulated and proved by shifts of the breathing vibration frequency dependent on the structure of isomeric ligand

  17. Biomedical applications of SPION@APTES@PEG-folic acid@carboxylated quercetin nanodrug on various cancer cells

    International Nuclear Information System (INIS)

    Akal, Z.Ü.; Alpsoy, L.; Baykal, A.

    2016-01-01

    Highlights: • SPION has been synthesized via Reflux synthesis route. • SPION@APTES@FA-PEG@CQ nanodrug has super paramagnetic property. • SPION@APTES@FA-PEG@CQ nanodrug has cytotoxic, apoptotic and necrotic effects on HeLa and MCF-7 cells. • SPION@APTES@FA-PEG@CQ nanodrug can be potentially used for the delivery of quercetin to cervical and breast cancer cells. - Abstract: In this study, carboxylated quercetin (CQ) was conjugated to superparamagnetic iron oxide nanoparticles (SPIONs) which were modified by (3-aminopropyl) triethoxysilane (APTES), Folic acid (FA) and carboxylated Polyethylene glycol (PEG); (SPION@APTES@FA-PEG@CQ), nanodrug has been synthesized via polyol and accompanying by various chemical synthesis routes. The characterization of the final product was done via X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Thermal gravimetric analysis (TGA), Transmission electron spectroscopy (TEM) and Vibrating sample magnetometer (VSM). Its cytotoxic and apoptotic activities on over expressed folic acid receptor (FR + ) (MCF-7, HeLa) and none expressed folic acid receptor (FR-) (A549) cancer cell lines were determined by using MTT assay, Real-Time Cell Analysis, TUNEL assay, Annexin assay and RT-PCR analysis for Caspase3/7 respectively. SPION@APTES@FA-PEG@CQ nanodrug showed higher cytotoxicity against HeLa and MCF-7 cell lines as compared with A549 cell line. Moreover, SPION@APTES@FA-PEG@CQ nanodrug also caused higher apoptotic and necrotic effects in 100 μg/mL HeLa and MCF-7 cells than A549 cells. The findings showed that SPION@APTES@FA-PEG@CQ nanodrug has cytotoxic, apoptotic and necrotic effects on HeLa and MCF-7 which are FR over expressed cell lines and can be potentially used for the delivery of quercetin to cervical and breast cancer cells.

  18. Biomedical applications of SPION@APTES@PEG-folic acid@carboxylated quercetin nanodrug on various cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Akal, Z.Ü., E-mail: zulker@fatih.edu.tr [Department of Biology, 34500 Büyükçekmece, Istanbul (Turkey); Alpsoy, L. [Department of Biology, 34500 Büyükçekmece, Istanbul (Turkey); Department of Medical Biology, 34500 Büyükçekmece, Istanbul (Turkey); Baykal, A. [Department of Chemistry, Fatih University, 34500 Büyükçekmece, Istanbul (Turkey)

    2016-08-15

    Highlights: • SPION has been synthesized via Reflux synthesis route. • SPION@APTES@FA-PEG@CQ nanodrug has super paramagnetic property. • SPION@APTES@FA-PEG@CQ nanodrug has cytotoxic, apoptotic and necrotic effects on HeLa and MCF-7 cells. • SPION@APTES@FA-PEG@CQ nanodrug can be potentially used for the delivery of quercetin to cervical and breast cancer cells. - Abstract: In this study, carboxylated quercetin (CQ) was conjugated to superparamagnetic iron oxide nanoparticles (SPIONs) which were modified by (3-aminopropyl) triethoxysilane (APTES), Folic acid (FA) and carboxylated Polyethylene glycol (PEG); (SPION@APTES@FA-PEG@CQ), nanodrug has been synthesized via polyol and accompanying by various chemical synthesis routes. The characterization of the final product was done via X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Thermal gravimetric analysis (TGA), Transmission electron spectroscopy (TEM) and Vibrating sample magnetometer (VSM). Its cytotoxic and apoptotic activities on over expressed folic acid receptor (FR + ) (MCF-7, HeLa) and none expressed folic acid receptor (FR-) (A549) cancer cell lines were determined by using MTT assay, Real-Time Cell Analysis, TUNEL assay, Annexin assay and RT-PCR analysis for Caspase3/7 respectively. SPION@APTES@FA-PEG@CQ nanodrug showed higher cytotoxicity against HeLa and MCF-7 cell lines as compared with A549 cell line. Moreover, SPION@APTES@FA-PEG@CQ nanodrug also caused higher apoptotic and necrotic effects in 100 μg/mL HeLa and MCF-7 cells than A549 cells. The findings showed that SPION@APTES@FA-PEG@CQ nanodrug has cytotoxic, apoptotic and necrotic effects on HeLa and MCF-7 which are FR over expressed cell lines and can be potentially used for the delivery of quercetin to cervical and breast cancer cells.

  19. Influence of carboxylic acid type on microstructure and magnetic properties of polymeric complex sol–gel driven NiFe{sub 2}O{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Hessien, M.M. [Materials Science & Engineering Group, Department of Chemistry, Faculty of Science, Taif University (Saudi Arabia); Advanced Materials Dept, Central Metallurgical Research and Development Institute (CMRDI), P.O. Box: 87, Helwan, Cairo (Egypt); Mostafa, Nasser Y., E-mail: nmost69@yahoo.com [Materials Science & Engineering Group, Department of Chemistry, Faculty of Science, Taif University (Saudi Arabia); Department of Chemistry, Faculty of Science, Suez Canal University, Ismailia (Egypt); Abd-Elkader, Omar H. [Department of Zoology, Science College, King Saud University, P.O. Box 2455, Riyadh 11451 (Saudi Arabia); Electron Microscope and Thin Films Department, National Research Center (NRC), El-Behooth Street, Dokki, Cairo 12622 (Egypt)

    2016-01-15

    Citric, oxalic and tartaric acids were used for synthesis of NiFe{sub 2}O{sub 4} using polymeric complex precursor route. The dry precursor gels were calcined at various temperatures (400–1100 °C) for 2 h. All carboxylic acids produce iron-deficient NiFe{sub 2}O{sub 4} with considerable amount of α-Fe{sub 2}O{sub 3} at 400 °C. Increase in the annealing temperature caused reaction of α-Fe{sub 2}O{sub 3} with iron-deficient ferrite phase. The amount of initially formed α-Fe{sub 2}O{sub 3} is directly correlated with stability constant and inversely correlated with the decomposition temperature of Fe(III) carboxylate precursors. In case of tartaric acid precursor, single phase of the ferrite was obtained at 450 °C. However, in case of oxalic acid and citric acid precursors, single phase ferrite was obtained at 550 °C and 700 °C, respectively. The lattice parameters were increased with increasing annealing temperature and with decreasing the amount of α-Fe{sub 2}O{sub 3}. Maximum saturation magnetization (55 emu/g) was achieved using tartaric acid precursor annealed at 1100 °C. - Highlights: • Citric, oxalic and tartaric acids were used for synthesis of NiFe{sub 2}O{sub 4}. • Carboxylic acid type affects the produced powders. • At low temperatures all carboxylic acids produce iron-deficient NiFe{sub 2}O{sub 4} and α-Fe{sub 2}O{sub 3}. • α-Fe{sub 2}O{sub 3} is correlated with the decomposition of Fe(III) carboxylate precursors.

  20. Do carboximide–carboxylic acid combinations form co-crystals? The role of hydroxyl substitution on the formation of co-crystals and eutectics

    Directory of Open Access Journals (Sweden)

    Ramanpreet Kaur

    2015-05-01

    Full Text Available Carboxylic acids, amides and imides are key organic systems which provide understanding of molecular recognition and binding phenomena important in biological and pharmaceutical settings. In this context, studies of their mutual interactions and compatibility through co-crystallization may pave the way for greater understanding and new applications of their combinations. Extensive co-crystallization studies are available for carboxylic acid/amide combinations, but only a few examples of carboxylic acid/imide co-crystals are currently observed in the literature. The non-formation of co-crystals for carboxylic acid/imide combinations has previously been rationalized, based on steric and computed stability factors. In the light of the growing awareness of eutectic mixtures as an alternative outcome in co-crystallization experiments, the nature of various benzoic acid/cyclic imide combinations is established in this paper. Since an additional functional group can provide sites for new intermolecular interactions and, potentially, promote supramolecular growth into a co-crystal, benzoic acids decorated with one or more hydroxyl groups have been systematically screened for co-crystallization with one unsaturated and two saturated cyclic imides. The facile formation of an abundant number of hydroxybenzoic acid/cyclic carboximide co-crystals is reported, including polymorphic and variable stoichiometry co-crystals. In the cases where co-crystals did not form, the combinations are shown invariably to result in eutectics. The presence or absence and geometric disposition of hydroxyl functionality on benzoic acid is thus found to drive the formation of co-crystals or eutectics for the studied carboxylic acid/imide combinations.

  1. Use of a polystyrene-divinylbenzene-based weakly acidic cation-exchange resin column and propionic acid as an eluent in ion-exclusion/adsorption chromatography of aliphatic carboxylic acids and ethanol in food samples.

    Science.gov (United States)

    Mori, Masanobu; Hironaga, Takahiro; Kajiwara, Hiroe; Nakatani, Nobutake; Kozaki, Daisuke; Itabashi, Hideyuki; Tanaka, Kazuhiko

    2011-01-01

    We developed an ion-exclusion/adsorption chromatography (IEAC) method employing a polystyrene-divinylbenzene-based weakly acidic cation-exchange resin (PS-WCX) column with propionic acid as the eluent for the simultaneous determination of multivalent aliphatic carboxylic acids and ethanol in food samples. The PS-WCX column well resolved mono-, di-, and trivalent carboxylic acids in the acidic eluent. Propionic acid as the eluent gave a higher signal-to-noise ratio, and enabled sensitive conductimetric detection of analyte acids. We found the optimal separation condition to be the combination of a PS-WCX column and 20-mM propionic acid. Practical applicability of the developed method was confirmed by using a short precolumn with a strongly acidic cation-exchange resin in the H(+)-form connected before the separation column; this was to remove cations from food samples by converting them to hydrogen ions. Consequently, common carboxylic acids and ethanol in beer, wine, and soy sauce were successfully separated by the developed method.

  2. 75 FR 78243 - Propionic Acid and Salts, Urea Sulfate, Methidathion, and Methyl Parathion; Registration Review...

    Science.gov (United States)

    2010-12-15

    ... ENVIRONMENTAL PROTECTION AGENCY [EPA-HQ-OPP-2010-0650; FRL-8855-5] Propionic Acid and Salts, Urea.... 4078, urea sulfate, case no. 7213, methidathion, case no. 0034, and methyl parathion, case no. 0153... pesticides in the table below--propionic acid and salts, case 4078, urea sulfate, case no. 7213, methidathion...

  3. 40 CFR 721.10097 - Disubstituted benzenesulfonic acid, alkali metal salt (generic).

    Science.gov (United States)

    2010-07-01

    ... chemical substance identified generically as disubstituted benzenesulfonic acid, alkali metal salt (PMN P... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Disubstituted benzenesulfonic acid, alkali metal salt (generic). 721.10097 Section 721.10097 Protection of Environment ENVIRONMENTAL...

  4. CO2 Capture from Flue Gas using Amino Acid Salt Solutions

    DEFF Research Database (Denmark)

    Lerche, Benedicte Mai; Stenby, Erling Halfdan; Thomsen, Kaj

    2009-01-01

    difficult. Amino acid salt solutions have emerged as an alternative to the alkanolamine solutions. A number of advantages make amino acid salt solutions attractive solvents for CO2 capture from flue gas. In the present study CO2 absorption in aqueous solutions of 0.5 M potassium glycinate and 0.5 M...

  5. Viscosities of oxalic acid and its salts in water and binary aqueous ...

    Indian Academy of Sciences (India)

    Unknown

    Viscosities; oxalic acid and its salts; water + THF mixtures; structure-breakers. 1. Introduction ... has found its application in the organic syntheses as manifested from ... water. In other words, these results indicate that oxalic acid and its salts mix ...

  6. 6-Substituted 3,4-dihydro-naphthalene-2-carboxylic acids: synthesis and structure-activity studies in a novel class of human 5alpha reductase inhibitors.

    Science.gov (United States)

    Baston, Eckhard; Salem, Ola I A; Hartmann, Rolf W

    2002-10-01

    Novel 3,4-dihydro-naphthalene-2-carboxylic acids were synthesized and evaluated for 5alpha reductase inhibitory activity. This enzyme exists in two isoforms and is a pharmacological target for the treatment of benign prostatic hyperplasia, male pattern baldness and acne. In the present study non-steroidal compounds capable of mimicking the transition state of the steroidal substrates were prepared. The synthetic strategy for the preparation of compounds 1-6 consisted of triflation followed by subsequent Heck-type carboxylation or methoxy carbonylation for 6-phenyl-3,4-dihydronaphthalen-2(1H)-one 1c. A Negishi-type coupling reaction between 6-(trifluoro-methanesulfonyloxy)-3,4-dihydro-naphthalene-2-carboxylic acid methyl ester 7b and various aryl bromides led, after further transformations, to 6-substituted 3,4-dihydro-naphthalene-2-carboxylic acids 7-15. In a similar way the corresponding naphthalene-2-carboxylic acids 16 and 17 were obtained. The DU 145 cell line and prostate homogenates served as enzyme sources for the human type 1 and type 2 isozymes, whereas ventral prostate was employed to evaluate rat isozyme inhibitory potency. The most active inhibitors identified in this study were 6-[4-(N,N-dicyclohexylaminocarbonyl)phenyl]-3,4-dihydro-naphthalene-2-carboxylic acid (3) (IC50 = 0.09 microM, rat type 1), 6-[3-(N,N-dicyclohexylaminocarbonyl)phenyl]-3,4-dihydro-naphthalene-2-carboxylic acid (13) (IC50 = 0.75 microM, human type 2; IC50 = 0.81 microM, human type 1) and 6-[4-(N,N-diisopropylamino-carbonyl)phenyl]naphthalene-2-carboxylic acid (16) (IC50 = 0.2 microM, human type 2). The latter compound was shown to deactivate the enzyme in an uncompetitive manner (Ki = 90 nM; Km, Testosterone = 0.8-1.0 microM) similar to the steroidal inhibitor Epristeride. Select inhibitors (13 and 16) were tested in vivo using testosterone propionate-treated, juvenile, orchiectomized SD-rats. None of the compounds was active at a dose of 25 mg/kg. This result might in part be

  7. Prediction of protein modification sites of pyrrolidone carboxylic acid using mRMR feature selection and analysis.

    Directory of Open Access Journals (Sweden)

    Lu-Lu Zheng

    Full Text Available Pyrrolidone carboxylic acid (PCA is formed during a common post-translational modification (PTM of extracellular and multi-pass membrane proteins. In this study, we developed a new predictor to predict the modification sites of PCA based on maximum relevance minimum redundancy (mRMR and incremental feature selection (IFS. We incorporated 727 features that belonged to 7 kinds of protein properties to predict the modification sites, including sequence conservation, residual disorder, amino acid factor, secondary structure and solvent accessibility, gain/loss of amino acid during evolution, propensity of amino acid to be conserved at protein-protein interface and protein surface, and deviation of side chain carbon atom number. Among these 727 features, 244 features were selected by mRMR and IFS as the optimized features for the prediction, with which the prediction model achieved a maximum of MCC of 0.7812. Feature analysis showed that all feature types contributed to the modification process. Further site-specific feature analysis showed that the features derived from PCA's surrounding sites contributed more to the determination of PCA sites than other sites. The detailed feature analysis in this paper might provide important clues for understanding the mechanism of the PCA formation and guide relevant experimental validations.

  8. Synthesis of new derivatives of 1-(3-aminophenyl-4-benzoyl-5-phenyl-1H-pyrazole-3-carboxylic acid

    Directory of Open Access Journals (Sweden)

    RAHMI KASIMOGULLAR

    2010-12-01

    Full Text Available 1-(3-Aminophenyl-4-benzoyl-5-phenyl-1H-pyrazole-3-carboxylic acid (1 was synthesized according to the literature. 2-(3-Aminophenyl-2,6-dihydro-3,4-diphenyl-7H-pyrazolo[3,4-d]pyridazin-7-one (5 was obtained by the cyclocondensation reaction of 1 with hydrazine hydrate. New pyrazole derivatives of compounds 1 and 5 were synthesized by their reaction with β-diketones, β-ketoesters, β-naphthol, phenol and various other reagents. The structures of the synthesized compounds were characterized by 1H-NMR, 13C-NMR, IR and mass spectroscopy, as well as elemental analysis.

  9. Discovery of a low-systemic-exposure DGAT-1 inhibitor with a picolinoylpyrrolidine-2-carboxylic acid moiety.

    Science.gov (United States)

    Yan, Jianwei; Wang, Gaihong; Dang, Xiangyu; Guo, Binbin; Chen, Wuhong; Wang, Ting; Zeng, Limin; Wang, Heyao; Hu, Youhong

    2017-09-01

    A series of diacylglycerol O-acyltransferase 1 (DGAT-1) inhibitors with a picolinoylpyrrolidine-2-carboxylic acid moiety were designed and synthesized. Of these compounds, compound 22 exhibited excellent DGAT-1-inhibitory activity (hDGAT-1 enzyme assay, 50% inhibitory concentration [IC 50 ]=3.5±0.9nM) and effectively reduced the intracellular triglyceride contents in 3T3-L1, HepG2 and Caco-2 cells. A preliminary study of the plasma and tissue distributions of compound 22 in mice revealed low plasma exposure and high concentrations in different segments of the intestine and liver, which may facilitate targeting DGAT-1. Furthermore, in an acute lipid challenge test, compound 22 showed a dose-dependent inhibitory effect on high-serum triglycerides in C57/KSJ mice induced by olive oil (1, 3, and 10mg/kg, i.g.). Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. High-performance liquid chromatographic enantioseparation of monoterpene-based 2-amino carboxylic acids on macrocyclic glycopeptide-based phases.

    Science.gov (United States)

    Sipos, László; Ilisz, István; Pataj, Zoltán; Szakonyi, Zsolt; Fülöp, Ferenc; Armstrong, Daniel W; Péter, Antal

    2010-10-29

    The enantiomers of five monoterpene-based 2-amino carboxylic acids were directly separated on chiral stationary phases containing macrocyclic glycopeptide antibiotics such as teicoplanin (Astec Chirobiotic T and T2) and teicoplanin aglycone (Chirobiotic TAG) as chiral selectors. The effects of pH, the mobile phase composition, the structure of the analyte and temperature on the separations were investigated. Experiments were performed at constant mobile phase compositions in the temperature range 10-40°C to study the effects of temperature and thermodynamic parameters on separations. Apparent thermodynamic parameters and T(iso) values were calculated from plots of ln k or ln α versus 1/T. Some mechanistic aspects of the chiral recognition process are discussed with respect to the structures of the analytes. It was found that the enantioseparations were in most cases enthalpy driven. The sequence of elution of the enantiomers was determined in all cases. Copyright © 2010 Elsevier B.V. All rights reserved.

  11. Reactions and reaction intermediates on iron surfaces--1. Methanol, ethanol, and isopropanol on Fe(100). 2. Hydrocarbons and carboxylic acids

    Energy Technology Data Exchange (ETDEWEB)

    Benziger, J.B.; Madix, R.J.

    1980-09-01

    Temperature-programed desorption and ESCA showed that the alcohols formed alkoxy intermediates on Fe(100) surfaces at room temperature, but that the methoxy and ethoxy species were much more stable than the isopropoxy intermediate. The alkoxy species reacted above 400/sup 0/K by decomposing into carbon monoxide and hydrogen, hydrogenation to alcohol, and scission of C-C and C-O bonds with hydrogenation of the hydrocarbon fragments. Ethylene, acetylene, and cis-2-butene formed stable, unidentified surface species. Methyl chloride formed stable surface methyl groups which decomposed into hydrogen and surface carbide at 475/sup 0/K. Formic and acetic acids yielded stable carboxylate intermediates which decomposed above 490/sup 0/K to hydrogen, carbon monoxide, and carbon dioxide. The studies suggested that the alkoxy surface species may be important intermediates in the Fischer-Tropsch reaction on iron.

  12. Utilization of oriented crystal growth for screening of aromatic carboxylic acids cocrystallization with urea

    Science.gov (United States)

    Przybyłek, Maciej; Ziółkowska, Dorota; Kobierski, Mirosław; Mroczyńska, Karina; Cysewski, Piotr

    2016-01-01

    The possibility of molecular complex formation in the solid state of urea with benzoic acid analogues was measured directly on the crystallite films deposited on the glass surface using powder X-ray diffractometry (PXRD). Obtained solid mixtures were also analyzed using Fourier transform infrared spectroscopy (FTIR). The simple droplet evaporation method was found to be efficient, robust, fast and cost-preserving approach for first stage cocrystal screening. Additionally, the application of orientation effect to cocrystal screening simplifies the analysis due to damping of majority of diffraction signals coming from coformers. During validation phase the proposed approach successfully reproduced both positive cases of cocrystallization (urea:salicylic acid and urea:4-hydroxy benzoic acid) as well as pairs of co-formers immiscible in the solid state (urea:benzoic acid and urea:acetylsalicylic acids). Based on validated approach new cocrystals of urea were identified in complexes with 3-hydroxybenzoic acid, 2,4-dihydroxybenzoic acid, 2,5-dihydroxybenzoic acid, 2,6-dihydroxybenzoic acid and 3,5-dihydroxybenzoic acid. In all cases formation of multicomponent crystal phase was confirmed by the appearance of new reflexes on the diffraction patterns and FTIR absorption band shifts of O-H and N-H groups.

  13. New derivatives of 3,4-dihydroisoquinoline-3-carboxylic acid with free-radical scavenging, D-amino acid oxidase, acetylcholinesterase and butyrylcholinesterase inhibitory activity.

    Science.gov (United States)

    Solecka, Jolanta; Guśpiel, Adam; Postek, Magdalena; Ziemska, Joanna; Kawęcki, Robert; Lęczycka, Katarzyna; Osior, Agnieszka; Pietrzak, Bartłomiej; Pypowski, Krzysztof; Wyrzykowska, Agata

    2014-09-30

    A series of 3,4-dihydroisoquinoline-3-carboxylic acid derivatives were synthesised and tested for their free-radical scavenging activity using 2,2-diphenyl-1-picrylhydrazyl radical (DPPH·), 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical (ABTS·+), superoxide anion radical (O2·-) and nitric oxide radical (·NO) assays. We also studied d-amino acid oxidase (DAAO), acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) inhibitory activity. Almost each of newly synthesised compounds exhibited radical scavenging capabilities. Moreover, several compounds showed moderate inhibitory activities against DAAO, AChE and BuChE. Compounds with significant free-radical scavenging activity may be potential candidates for therapeutics used in oxidative-stress-related diseases.

  14. Ethylene-enhanced catabolism of [14C]indole-3-acetic acid to indole-3-carboxylic acid in citrus leaf tissues

    International Nuclear Information System (INIS)

    Sagee, O.; Riov, J.; Goren, J.

    1990-01-01

    Exogenous [ 14 C]indole-3-acetic acid (IAA) is conjugated in citrus (Citrus sinensis) leaf tissues to one major substance which has been identified as indole-3-acetylaspartic acid (IAAsp). Ethylene pretreatment enhanced the catabolism of [ 14 C]IAA to indole-3-carboxylic acid (ICA), which accumulated as glucose esters (ICGlu). Increased formation of ICGlu by ethylene was accompanied by a concomitant decrease in IAAsp formation. IAAsp and ICGlu were identified by combined gas chromatography-mass spectrometry. Formation of ICGlu was dependent on the concentration of ethylene and the duration of the ethylene pretreatment. It is suggested that the catabolism of IAA to ICA may be one of the mechanisms by which ethylene endogenous IAA levels

  15. Enhancing Skin Permeation of Biphenylacetic Acid (BPA) Using Salt Formation with Organic and Alkali Metal Bases.

    Science.gov (United States)

    Pawar, Vijay; Naik, Prashant; Giridhar, Rajani; Yadav, Mange Ram

    2015-01-01

    In the present study, a series of organic and alkali metal salts of biphenylacetic acid (BPA) have been prepared and evaluated in vitro for percutaneous drug delivery. The physicochemical properties of BPA salts were determined using solubility measurements, DSC, and IR. The DSC thermogram and FTIR spectra confirmed the salt formation with organic and alkali metal bases. Among the series, salts with organic amines (ethanolamine, diethanolamine, triethanolamine, and diethylamine) had lowered melting points while the alkali metal salt (sodium) had a higher melting point than BPA. The in vitro study showed that salt formation improves the physicochemical properties of BPA, leading to improved permeability through the skin. Amongst all the prepared salts, ethanolamine salt (1b) showed 7.2- and 5.4-fold higher skin permeation than the parent drug at pH 7.4 and 5.0, respectively, using rat skin.

  16. Uranium (IV) carboxylates - I

    Energy Technology Data Exchange (ETDEWEB)

    Satpathy, K C; Patnaik, A K [Sambalpur Univ. (India). Dept. of Chemistry

    1975-11-01

    A few uranium(IV) carboxylates with monochloro and trichloro acetic acid, glycine, malic, citric, adipic, o-toluic, anthranilic and salicylic acids have been prepared by photolytic methods. The I.R. spectra of these compounds are recorded and basing on the spectral data, structure of the compounds have been suggested.

  17. Complexes of molybdenum (6) and tungsten (6) with amino- and pyridine carboxylic acids

    Energy Technology Data Exchange (ETDEWEB)

    Spitsyn, V I; Mozgin, S V; Felin, M G; Subbotina, N A; Ajzenberg, M I [Moskovskij Gosudarstvennyj Univ. (USSR)

    1984-01-01

    By interaction of Na/sub 2/MO/sub 4/ with amino acid excess in muriatic medium the complexes Mo/sub 2/O/sub 4/ (OH)/sub 3/L (LH-anthranilic, nicotinic acids, histidine), Mo/sub 2/O/sub 5/ (OH)L' (L'H-..cap alpha..- and ..beta..-alanine, valine, isonicotinic acid), W/sub 3/O/sub 8/ (OH) (H/sub 2/O)/sub 4/ L'' (L'H-nicotinic, isonicotinic acids, histidine) are isolated. On the basis of the data of elementary analysis, IR spectroscopy and thermogravimetry assumptions on their composition and structure have been suggested.

  18. Complexes of molybdenum (6) and tungsten (6) with amino- and pyridine carboxylic acids

    International Nuclear Information System (INIS)

    Spitsyn, V.I.; Mozgin, S.V.; Felin, M.G.; Subbotina, N.A.; Ajzenberg, M.I.

    1984-01-01

    By interaction of Na 2 MO 4 With amino acid excess in muriatic medium the complexes Mo 2 O 4 (OH) 3 L (LH-anthranilic, nicotinic acids, histidine), Mo 2 O 5 (OH)L' (L'H-α- and β-alanine, valine, isonicotinic acid), W 3 O 8 (OH) (H 2 O) 4 L'' (L'H-nicotinic, isonicotinic acids, histidine) are isolated. On the basis of the data of elementary analysis, IR spectrosfopy and thermogravimetry assumptions on their composition and structure have been suggested

  19. Determination of short chain carboxylic acids in vegetable oils and fats using ion exclusion chromatography electrospray ionization mass spectrometry.

    Science.gov (United States)

    Viidanoja, Jyrki

    2015-02-27

    A new method for quantification of short chain C1-C6 carboxylic acids in vegetable oils and fats by employing Liquid Chromatography Mass Spectrometry (LC-MS) has been developed. The method requires minor sample preparation and applies non-conventional Electrospray Ionization (ESI) liquid phase chemistry. Samples are first dissolved in chloroform and then extracted using water that has been spiked with stable isotope labeled internal standards that are used for signal normalization and absolute quantification of selected acids. The analytes are separated using Ion Exclusion Chromatography (IEC) and detected with Electrospray Ionization Mass Spectrometry (ESI-MS) as deprotonated molecules. Prior to ionization the eluent that contains hydrochloric acid is modified post-column to ensure good ionization efficiency of the analytes. The averaged within run precision and between run precision were generally lower than 8%. The accuracy was between 85 and 115% for most of the analytes. The Lower Limit of Quantification (LLOQ) ranged from 0.006 to 7mg/kg. It is shown that this method offers good selectivity in cases where UV detection fails to produce reliable results. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. HTGR fuel development: loading of uranium on carboxylic acid cation-exchange resins using solvent extraction of nitrate

    International Nuclear Information System (INIS)

    Haas, P.A.

    1975-09-01

    The reference fuel kernel for recycle of 233 U to HTGR's (High-Temperature Gas-Cooled Reactors) is prepared by loading carboxylic acid cation-exchange resins with uranium and carbonizing at controlled conditions. The purified 233 UO 2 (NO 3 ) 2 solution from a fuel reprocessing plant contains excess HNO 3 (NO 3 - /U ratio of approximately 2.2). The reference flowsheet for a 233 U recycle fuel facility at Oak Ridge uses solvent extraction of nitrate by a 0.3 M secondary amine in a hydrocarbon diluent to prepare acid-deficient uranyl nitrate. This nitrate extraction, along with resin loading and amine regeneration steps, was demonstrated in 14 runs. No significant operating difficulties were encountered. The process is controlled via in-line pH measurements for the acid-deficient uranyl nitrate solutions. Information was developed on pH values for uranyl nitrate solution vs NO 3 - /U mole ratios, resin loading kinetics, resin drying requirements, and other resin loading process parameters. Calculations made to estimate the capacities of equipment that is geometrically safe with respect to control of nuclear criticality indicate 100 kg/day or more of uranium for single nitrate extraction lines with one continuous resin loading contactor or four batch loading contactors. (auth)

  1. Mass spectrometric studies of stable isotope-labelled carboxylic acid derivatives

    International Nuclear Information System (INIS)

    Andersson, B.Aa.; Dinger, F.; Dinh-Nguyen, N.

    1975-01-01

    Low resolution mass spectra of deuterium and carbon-13 labelled fatty acid pyrrolidides are discussed. The simple fragmentation pattern of pyrrolidides makes them superior to other derivatives, regarding location of isotopes. Deuteriation of ethylenic fatty acid pyrrolidides therefore seems to be an improved method to locate carbon-carbon double bonds by mass spectrometry. (author)

  2. CEC enantioseparations of carboxylic acids on silica-based monoliths modified with ergot alkaloid derivative

    Czech Academy of Sciences Publication Activity Database

    Messina, A.; Moroni, S.; Flieger, Miroslav; Sinibaldi, M.; Ursini, O.

    2009-01-01

    Roč. 30, č. 16 (2009), s. 2890-2896 ISSN 0173-0835 Institutional research plan: CEZ:AV0Z50200510 Keywords : 2-Aryloxypropionic acids * chiral separations * dansyl amino acid derivatives Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 3.077, year: 2009

  3. Heterocycles [h]-Fused Onto 4-Oxoquinoline-3-Carboxylic Acid, Part VIII [1]. Convenient Synthesis and Antimicrobial Properties of Substituted Hexahydro[1,4]diazepino[2,3-h]quinoline-9-carboxylic acid and Its Tetrahydroquino[7,8-b]benzodiazepine Analog

    Directory of Open Access Journals (Sweden)

    Yusuf M. Al-Hiari

    2008-11-01

    Full Text Available [1,4]Diazepino[2,3-h]quinolone carboxylic acid 3 and its benzo-homolog tetrahydroquino[7,8-b]benzodiazepine-3-carboxylic acid 5 were prepared via PPAcatalyzed thermal lactamization of the respective 8-amino-7-substituted-1,4-dihydroquinoline-3-carboxylic acid derivatives 8, 10. The latter compounds were obtained by reduction of their 8-nitro-7-substituted-1,4-dihydroquinoline-3-carboxylic acid precursors 7, 9 which, in turn, were prepared by reaction of 7-chloro-1-cyclopropyl-6-fluoro-8-nitro-1,4-dihydroquinoline-3-carboxylic acid (6 with each of β-alanine and anthranilic acid. All intermediates and target compounds were characterized using elemental analysis, NMR, IR and MS spectral data. The prepared targets and the intermediates have shown interesting antibacterial activity mainly against Gram positive strains. In particular, compound 8 showed good activity against S. aureus (MIC = 0.39 μg/mL and B. subtilis (MIC = 0.78 μg/mL. Compounds 5a and 9 have also displayed good antifungal activity against C. albicans (MIC = 1.56 μg/mL and 0.78 μg/mL, respectively. None of the compounds tested showed any anticancer activity against solid breast cancer cell line MCF-7 cells or a human breast adenocarcinoma cell line.

  4. Modeling of the selective pertraction of carboxylic acids obtained by citric fermentation

    Directory of Open Access Journals (Sweden)

    Cascaval Dan

    2004-01-01

    Full Text Available Facilitated pertraction was applied for the selective separation of citric, maleic and succinic acids from a mixture obtained by citric fermentation. The pertraction equipment included a U-shaped cell containing 1,2-dichloro-ethane as the liquid membrane and Amberlite LA-2 as the carrier. The experimental data indicated that maleic and succinic acids can be initially selectively separated from citric acid, followed by the selectively separation of maleic acid from succinic acid. Using statistical analysis and a second order factorial experiment, two mathematical correlations describing the influence of the main process variables on pertraction selectivity were established. For both extraction systems, the considered variables controlled the extraction process to an extent of 92.9-99.9%, the carrier concentration inside the liquid membrane exhibiting the most important influence.

  5. Contents of carboxylic acids and two phenolics and antioxidant activity of dried portuguese wild edible mushrooms.

    Science.gov (United States)

    Ribeiro, Barbara; Rangel, Joana; Valentão, Patrícia; Baptista, Paula; Seabra, Rosa M; Andrade, Paula B

    2006-11-01

    The organic acids and phenolics compositions of nine wild edible mushrooms species (Suillus bellini, Tricholomopsis rutilans, Hygrophorus agathosmus, Amanita rubescens, Russula cyanoxantha, Boletus edulis, Tricholoma equestre, Suillus luteus, and Suillus granulatus) were determined by HPLC-UV and HPLC-DAD, respectively. The antioxidant potential of these species was also assessed by using the DPPH* scavenging assay. The results showed that all of the species presented a profile composed of at least five organic acids: oxalic, citric, malic, quinic, and fumaric acids. In a general way, the pair of malic plus quinic acids were the major compounds. Only very small amounts of two phenolic compounds were found in some of the analyzed species: p-hydroxybenzoic acid (in A. rubescens, R. cyanoxantha, and T. equestre) and quercetin (in S. luteus and S. granulatus). All of the species exhibited a concentration-dependent scavenging ability against DPPH*. T. rutilans revealed the highest antioxidant capacity.

  6. Hydrophilic carboxylic acids and iridoid glycosides in the juice of American and European cranberries (Vaccinium macrocarpon and V. oxycoccos), lingonberries (V. vitis-idaea), and blueberries (V. myrtillus)

    DEFF Research Database (Denmark)

    Jensen, Heidi Dorthe; Krogfelt, Karen A; Cornett, Claus

    2002-01-01

    iridoid glucosides were shown to be monotropein and 6,7-dihydromonotropein by MS and NMR spectroscopy. A fast reversed-phase HPLC method for quantification of the hydrophilic carboxylic acids was developed and used for analyses of cranberry, lingonberry, and blueberry juices. The level of hydrophilic...

  7. Reactive extraction of carboxylic acids from apolar hydrocarbons using aqueous solutions of sodium hydrogen carbonate with back-recovery using carbon dioxide under pressure

    NARCIS (Netherlands)

    Kuzmanovic, B.; Kuipers, N.J.M.; de Haan, A.B.; Kwant, Gerard

    2005-01-01

    A combination of using an aqueous solution of sodium hydrogen carbonate for forward-extraction of carboxylic acids from a dilute apolar organic solvent, and carbon dioxide under pressure for its back-recovery, is studied. Used in combination, these two steps might provide a technique for the

  8. Structural and thermodynamic study of rare earth(III) complexation by poly-hydroxylated carboxylic acids: synthesis of new extractants and outlook for the extraction of these cations

    International Nuclear Information System (INIS)

    Aury, S.

    2002-12-01

    The aim of this work is: to improve the knowledge on the binding sites of the poly-hydroxylated carboxylic acids with the trivalent lanthanide(III) ions by comparing them to gluconic acid (previously studied) and to molecules with different configuration and with a variable number of OH functions (threonic acid, glyceric acid, 2-hydroxy-butanoic acid, 3-hydroxy-butanoic acid). To find the best complexing agent among different acids (aldonic acids, aldaric acids, di-hydroxybenzoic acids) (determination of the set of complexes and their stability constants by potentiometry, NMR and UV-Visible spectroscopy). To synthesize hydrophobic monoamides from one lactone form of saccharic acid, to study their complexing power and their capacity to extract the trivalent lanthanide(III) ions. (author)

  9. Effect of phenols and carboxylic acids on photochromism of 1-alkyl-2-(arylazo)imidazoles

    Energy Technology Data Exchange (ETDEWEB)

    Gayen, Pallab [Inorganic Chemistry Section, Department of Chemistry, Jadavpur University, Kolkata 700032 (India); Sinha, Chittaranjan, E-mail: c_r_sinha@yahoo.com [Inorganic Chemistry Section, Department of Chemistry, Jadavpur University, Kolkata 700032 (India)

    2012-09-15

    Light irradiated trans-to-cis isomerization of 1-alkyl-2-(arylazo)imidazole in the presence of phenol, catechol, benzoic acid and salicylic acid (called co-factors) has been studied in this work. The rate of trans{yields}cis photoisomerization is decreased in the presence of co-factor in the medium and is dependent on the concentration of active quotient about photochrome. The decrease in rate follows catechol>benzoic acid>phenol>salicylic acid. This trend is due to the effects of dissociation ability of -O-H/-COOH, intermolecular association of the molecules etc. The reverse change, cis-to-trans, is very slow in light irradiation and has been carried out by a thermal process in the dark. The quantum yield of isomerization follows the same sequence of effects of co-factors. - Highlights: Black-Right-Pointing-Pointer Photoisomerisation of 1-alkyl-2-(arylazo)imidazoles, trans-to-cis, is described in this work. Black-Right-Pointing-Pointer The process is sensitive to the environment of the photochrome and the solution. Black-Right-Pointing-Pointer The rate of photoisomerization decreases as catechol>benzoic acid>phenol>salicylic acid. Black-Right-Pointing-Pointer The reverse isomerization, cis-to-trans is very slow with light and has been carried out with heat. Black-Right-Pointing-Pointer The activation energy is less than these values when carried out in fresh solution only.

  10. Effect of phenols and carboxylic acids on photochromism of 1-alkyl-2-(arylazo)imidazoles

    International Nuclear Information System (INIS)

    Gayen, Pallab; Sinha, Chittaranjan

    2012-01-01

    Light irradiated trans-to-cis isomerization of 1-alkyl-2-(arylazo)imidazole in the presence of phenol, catechol, benzoic acid and salicylic acid (called co-factors) has been studied in this work. The rate of trans→cis photoisomerization is decreased in the presence of co-factor in the medium and is dependent on the concentration of active quotient about photochrome. The decrease in rate follows catechol>benzoic acid>phenol>salicylic acid. This trend is due to the effects of dissociation ability of –O–H/–COOH, intermolecular association of the molecules etc. The reverse change, cis-to-trans, is very slow in light irradiation and has been carried out by a thermal process in the dark. The quantum yield of isomerization follows the same sequence of effects of co-factors. - Highlights: ► Photoisomerisation of 1-alkyl-2-(arylazo)imidazoles, trans-to-cis, is described in this work. ► The process is sensitive to the environment of the photochrome and the solution. ► The rate of photoisomerization decreases as catechol>benzoic acid>phenol>salicylic acid. ► The reverse isomerization, cis-to-trans is very slow with light and has been carried out with heat. ► The activation energy is less than these values when carried out in fresh solution only.

  11. A Novel Strategy Towards the Asymmetric Synthesis of Orthogonally Funtionalised 2-N-Benzyl-N-α-methylbenzylamino- 5-carboxymethyl-cyclopentane-1-carboxylic acid.

    Directory of Open Access Journals (Sweden)

    Julio G. Urones

    2004-04-01

    Full Text Available The asymmetric synthesis of the orthogonally funtionalised compounds tert-butyl 2-N-benzyl-N-α-methylbenzylamino-5-methoxycarbonylmethylcyclopentane- 1-carboxylate and methyl 2-N-benzyl-N-α-methylbenzylamino-5–carboxymethylcyclo- pentane-1-carboxylate by a domino reaction of tert-butyl methyl (E,E-octa-2,6- diendioate with lithium N-α-methylbenzyl-N-benzylamide initiated by a Michael addition, subsequent 5-exo-trig intramolecular cyclisation and posterior selective hydrolysis with trifluoroacetic acid is reported.

  12. Effects of oxidizing adulterants on detection of 11-nor-delta9-THC-9-carboxylic acid in urine.

    Science.gov (United States)

    Paul, Buddha D; Jacobs, Aaron

    2002-10-01

    Bleach, nitrite, chromate, and hydrogen peroxide-peroxidase are effective urine adulterants used by the illicit drug users to conceal marijuana-positive results. Methods for detecting nitrite and chromate are available. Effects of other oxidizing agents that could possibly be used as adulterants and are difficult to detect or measure are presented in this report. Urine samples containing 40 ng/mL of 11-nor-delta9-THC-9-carboxylic acid (THC-acid) were treated with 10 mmol/L of commonly available oxidizing agents. Effects of horseradish peroxidase of activity 10 unit/mL and extracts from 2.5 g of red radish (Raphanus sativus, Radicula group), horseradish (Armoracia rusticana), Japanese radish (Raphanus sativus, Daikon group), and black mustard seeds (Brassica nigra), all with 10 mmol/L of hydrogen peroxide, were also examined. After 5 min, 16 h and 48 h of exposure at room temperature (23 degrees C) the specimens were tested by a gas chromatographic-mass spectrometric method for THC-acid. A control group treated with sodium hydrosulfite to reduce the oxidants, was also tested to investigate the effect of oxidizing agents on THC-acid in the extraction method. THC-acid was lost completely in the extraction method when treated with chromate, nitrite, oxone, and hydrogen peroxide/ferrous ammonium sulfate (Fenton's reagent). Some losses were also observed with persulfate and periodate (up to 25%). These oxidants, and other oxidizing agents like permanganate, periodate, peroxidase, and extracts from red radish, horseradish, Japanese radish and black mustard seeds destroyed most of the THC-acid (> 94%) within 48 h of exposure. Chlorate, perchlorate, iodate, and oxychloride under these conditions showed little or no effect. Complete loss was observed when THC-acid was exposed to 50 mmol/L of oxychloride for 48 h. Several oxidizing adulterants that are difficult to test by the present urine adulterant testing methods showed considerable effects on the destruction of THC-acid

  13. Approaches to α-amino acids via rearrangement to electron-deficient nitrogen: Beckmann and Hofmann rearrangements of appropriate carboxyl-protected substrates

    Directory of Open Access Journals (Sweden)

    Sosale Chandrasekhar

    2012-08-01

    Full Text Available The titled approaches were effected with various 2-substituted benzoylacetic acid oximes 3 (Beckmann and 2-substituted malonamic acids 9 (Hofmann, their carboxyl groups being masked as a 2,4,10-trioxaadamantane unit (an orthoacetate. The oxime mesylates have been rearranged with basic Al2O3 in refluxing CHCl3, and the malonamic acids with phenyliodoso acetate and KOH/MeOH. Both routes are characterized by excellent overall yields. Structure confirmation of final products was conducted with X-ray diffraction in selected cases. The final N-benzoyl and N-(methoxycarbonyl products are α-amino acids with both carboxyl and amino protection; hence, they are of great interest in peptide synthesis.

  14. Proton-conducting membranes based on benzimidazole-containing sulfonated poly(ether ether ketone) compared with their carboxyl acid form

    Energy Technology Data Exchange (ETDEWEB)

    Li, Hongtao; Wu, Jing; Zhao, Chengji; Zhang, Gang; Zhang, Yang; Shao, Ke; Xu, Dan; Lin, Haidan; Han, Miaomiao; Na, Hui [Alan G MacDiarmid Institute, College of Chemistry, Jilin University, Changchun 130012 (China)

    2009-10-15

    A series of sulfonated poly(ether ether ketone) containing pendant carboxyl (C-SPEEKs) have been synthesized using a nucleophilic polycondesation reaction. A condensation reaction between 1,2-diaminobenzene and carboxyl resulted in a new series of copolymers containing benzimidazole groups (SPEEK-BIms). The expected structures of the sulfonated copolymers are confirmed by {sup 1}H NMR. The dependence of ion exchange capacity, water uptake, proton conductivity and methanol diffusion coefficient of SPEEK-BIm membranes has been studied and compared with their carboxyl acid form. The results suggest that the introduction of benzimidazole groups may be responsible for many excellent properties of the membranes for fuel cell. It is noticeable that the markedly improved oxidative stability is benefit for the application of membrane. (author)

  15. Selenium speciation in urine by ion-pairing chromatography with perfluorinated carboxylic acids and ICP-MS detection

    DEFF Research Database (Denmark)

    Gammelgaard, Bente; Bendahl, L.; Sidenius, U.

    2002-01-01

    Five aqueous standards, selenomethionine (SeMet), methylselenomethionine (MeSeMet), methylselenocysteine (MeSeCys), selenogammaaminobutyric acid (SeGaba) and the trimethylselenonium ion (TMSe), were separated in ion-pairing chromatographic systems based on perfluorinated carboxylic acids in metha...... were major compounds in urine samples-even after massive consumption of selenium-containing supplements. The selenium species in the urine samples showed a limited stability, as they changed during storage at +4 degreesC as well as -18 degreesC...... of between 2.3 and 5.1 pg. Urine samples from different individuals before and during supplementation with selenomethionine were analysed. Several species were separated in the different urine samples. A major component eluting at the beginning of the chromatogram was predominant in many samples, especially...... after selenium consumption. This species was not identified and solid phase extraction experiments suggested that it was neutral. When different urine samples were spiked with the available standards, co-elution of species with TMSe, MeSeMet or SeMet was observed in some samples. None of these species...

  16. Calculated Third Order Rate Constants for Interpreting the Mechanisms of Hydrolyses of Chloroformates, Carboxylic Acid Halides, Sulfonyl Chlorides and Phosphorochloridates

    Directory of Open Access Journals (Sweden)

    T. William Bentley

    2015-05-01

    Full Text Available Hydrolyses of acid derivatives (e.g., carboxylic acid chlorides and fluorides, fluoro- and chloroformates, sulfonyl chlorides, phosphorochloridates, anhydrides exhibit pseudo-first order kinetics. Reaction mechanisms vary from those involving a cationic intermediate (SN1 to concerted SN2 processes, and further to third order reactions, in which one solvent molecule acts as the attacking nucleophile and a second molecule acts as a general base catalyst. A unified framework is discussed, in which there are two reaction channels—an SN1-SN2 spectrum and an SN2-SN3 spectrum. Third order rate constants (k3 are calculated for solvolytic reactions in a wide range of compositions of acetone-water mixtures, and are shown to be either approximately constant or correlated with the Grunwald-Winstein Y parameter. These data and kinetic solvent isotope effects, provide the experimental evidence for the SN2-SN3 spectrum (e.g., for chloro- and fluoroformates, chloroacetyl chloride, p-nitrobenzoyl p-toluenesulfonate, sulfonyl chlorides. Deviations from linearity lead to U- or V-shaped plots, which assist in the identification of the point at which the reaction channel changes from SN2-SN3 to SN1-SN2 (e.g., for benzoyl chloride.

  17. Permeability and toxicity characteristics of L-cysteine and 2-methyl-thiazolidine-4-carboxylic acid in Caco-2 cells.

    Science.gov (United States)

    Kartal-Hodzic, Alma; Marvola, Tuuli; Schmitt, Mechthild; Harju, Kirsi; Peltoniemi, Marikki; Sivén, Mia

    2013-01-01

    Acetaldehyde is a known mutagenic substance and has been classified as a group-one carcinogen by the WHO. It is possible to bind acetaldehyde locally in the gastrointestinal (GI) tract with the semi-essential amino acid l-cysteine, which reacts covalently with acetaldehyde and forms compound 2-methyl-thiozolidine-4-carboxylic acid (MTCA). The Caco-2 cell line was used to determine the permeation of l-cysteine and MTCA, as well as the possible cell toxicity of both substances. Neither of the substances permeated through the Caco-2 cells at the concentrations used in this study, and only the highest concentration of MTCA affected the viability of the cells in the MTT (3-[4,5-dimethylthiazol-2yl]-2,5-diphenyltetrazolium bromide) test. These results showed that when l-cysteine is administered in formulations releasing it locally in the lower parts of GI tract, it is not absorbed but can react with acetaldehyde, and that neither l-cysteine nor MTCA is harmful to the cells when present locally in the upper parts of GI tract. This study also shows that MTCA is sensitive at a lower pH of 5.5. Since stable MTCA is desired in different parts of the GI tract, this observation raises concern over the influence of lower pH on l-cysteine-containing product ability to bind and eliminate carcinogenic acetaldehyde.

  18. Theoretical prediction of pKa in methanol: testing SM8 and SMD models for carboxylic acids, phenols, and amines.

    Science.gov (United States)

    Miguel, Elizabeth L M; Silva, Poliana L; Pliego, Josefredo R

    2014-05-29

    Methanol is a widely used solvent for chemical reactions and has solvation properties similar to those of water. However, the performance of continuum solvation models in this solvent has not been tested yet. In this report, we have investigated the performance of the SM8 and SMD models for pKa prediction of 26 carboxylic acids, 24 phenols, and 23 amines in methanol. The gas phase contribution was included at the X3LYP/TZVPP+diff//X3LYP/DZV+P(d) level. Using the proton exchange reaction with acetic acid, phenol, and ammonia as reference species leads to RMS error in the range of 1.4 to 3.6 pKa units. This finding suggests that the performance of the continuum models for methanol is similar to that found for aqueous solvent. Application of simple empirical correction through a linear equation leads to accurate pKa prediction, with uncertainty less than 0.8 units with the SM8 method. Testing with the less expensive PBE1PBE/6-311+G** method results in a slight improvement in the results.

  19. Spectroscopic and first principles investigation on 4-[(4-pyridinylmethylene)amino]-benzoic acid bearing pyridyl and carboxyl anchoring groups

    Science.gov (United States)

    Zhang, Lei; Wang, Qiaoyi

    2018-03-01

    We report a combined experimental and computational investigation on the structure and photophysics of 4-[(4-pyridinylmethylene)amino]-benzoic acid, a functional molecule bearing two anchoring groups for attachment onto a TiO2 surface and perovskite surface, for potential solar cell application. This molecule possesses interesting adsorption properties in perovskite solar cell because the pyridyl group serves as the Lewis base and targets Lewis acidic sites in the perovskite surface, while the carboxyl group targets TiO2 surface, improving the coupling between the perovskite surface and the TiO2 surface. The electronic structures of the molecule and its photochemistry are revealed by the UV-vis absorption spectra and the fluorescence spectra under visible light irradiation, which are combined with density functional theory (DFT) and time-dependent density functional theory (TDDFT) analysis. Considering the bi-anchoring groups and the conjugated π system embedded in the molecule, we anticipate it can molecular engineer the TiO2/perovskite interface in perovskite solar cell.

  20. Carboxylic acid-grafted mesoporous material and its high catalytic activity in one-pot three-component coupling reaction

    Directory of Open Access Journals (Sweden)

    Ruth Gomes

    2014-11-01

    Full Text Available A new carboxylic acid functionalized mesoporous organic polymer has been synthesized via in situ radical polymerization of divinylbenzene and acrylic acid using a mesoporous silica as a seed during the polymerization process under solvothermal conditions. The mesoporous material MPDVAA-1 has been thoroughly characterized employing powder XRD, solid state 13C cross polarization magic angle spinning-nuclear magnetic resonance, FT-IR spectroscopy, N2 sorption, HR-TEM, and NH3 temperature programmed desorption-thermal conductivity detector (TPD-TCD analysis to understand its porosity, chemical environment, bonding, and surface properties. The mesoporous polymer was used as a catalyst for a three comp onent Biginelli condensation between various aldehydes, β-keto esters, and urea/thioureas to give 3,4-dihydropyrimidine-2(1H-ones. The reactions were carried out under conventional heating as well as solvent-free microwave irradiation of solid components, and in both the cases, the mesoporous polymer MPDVAA-1 proved to be a powerful, robust, and reusable catalyst with high catalytic efficiency.

  1. Single amino acids in the carboxyl terminal domain of aquaporin-1 contribute to cGMP-dependent ion channel activation

    Directory of Open Access Journals (Sweden)

    Yool Andrea J

    2003-10-01

    Full Text Available Abstract Background Aquaporin-1 (AQP1 functions as an osmotic water channel and a gated cation channel. Activation of the AQP1 ion conductance by intracellular cGMP was hypothesized to involve the carboxyl (C- terminus, based on amino acid sequence alignments with cyclic-nucleotide-gated channels and cGMP-selective phosphodiesterases. Results Voltage clamp analyses of human AQP1 channels expressed in Xenopus oocytes demonstrated that the nitric oxide donor, sodium nitroprusside (SNP; 3–14 mM activated the ionic conductance response in a dose-dependent manner. Block of soluble guanylate cyclase prevented the response. Enzyme immunoassays confirmed a linear dose-dependent relationship between SNP and the resulting intracellular cGMP levels (up to 1700 fmol cGMP /oocyte at 14 mM SNP. Results here are the first to show that the efficacy of ion channel activation is decreased by mutations of AQP1 at conserved residues in the C-terminal domain (aspartate D237 and lysine K243. Conclusions These data support the idea that the limited amino acid sequence similarities found between three diverse classes of cGMP-binding proteins are significant to the function of AQP1 as a cGMP-gated ion channel, and provide direct evidence for the involvement of the AQP1 C-terminal domain in cGMP-mediated ion channel activation.

  2. Silver(I) and copper(II)-imidazolium carboxylates: Efficient catalysts ...

    Indian Academy of Sciences (India)

    GANESAN PRABUSANKAR

    the reaction between corresponding carboxylic acid ligands and metal salts. These new metal .... g), DMF (2 mL) and water (1 mL) was added; then, the sus- pension was ..... ence of five mol% potassium hydroxide as base in 1 and. Scheme 3.

  3. The Distant Double Bond Determines the Fate of the Carboxylic Group in the Dissociative Photoionization of Oleic Acid.

    Science.gov (United States)

    Heringa, Maarten F; Slowik, Jay G; Goldmann, Maximilian; Signorell, Ruth; Hemberger, Patrick; Bodi, Andras

    2017-12-15

    The valence threshold photoionization of oleic acid has been studied using synchrotron VUV radiation and imaging photoelectron photoion coincidence (iPEPICO) spectroscopy. An oleic acid aerosol beam was impacted on a copper thermodesorber, heated to 130 °C, to evaporate the particles quantitatively. Upon threshold photoionization, oleic acid produces the intact parent ion first, followed by dehydration at higher energies. Starting at ca. 10 eV, a large number of fragment ions slowly rise suggesting several fragmentation coordinates with quasi-degenerate activation energies. However, water loss is the dominant low-energy dissociation channel, and it is shown to be closely related to the unsaturated carbon chain. In the lowest-barrier process, one of the four allylic hydrogen atoms is transferred to the carboxyl group to form the leaving water molecule and a cyclic ketone fragment ion. A statistical model to analyze the breakdown diagram and measured rate constants yields a 0 K appearance energy of 9.77 eV, which can be compared with the density functional theory result of 9.19 eV. Alternative H-transfer steps yielding a terminal C=O group are ruled out based on energetics and kinetics arguments. Some of the previous photoionization mass spectrometric studies also reported 2 amu and 26 amu loss fragment ions, corresponding to hydrogen and acetylene loss. We could not identify such peaks in the mass spectrum of oleic acid. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Deracemization of Axially Chiral Nicotinamides by Dynamic Salt Formation with Enantiopure Dibenzoyltartaric Acid (DBTA

    Directory of Open Access Journals (Sweden)

    Fumitoshi Yagishita

    2013-11-01

    Full Text Available Dynamic atroposelective resolution of chiral salts derived from oily racemic nicotinamides and enantiopure dibenzoyltartaric acid (DBTA was achieved by crystallization. The absolute structures of the axial chiral nicotinamides were determined by X-ray structural analysis. The chirality could be controlled by the selection of enantiopure DBTA as a chiral auxiliary. The axial chirality generated by dynamic salt formation was retained for a long period after dissolving the chiral salt in solution even after removal of the chiral acid. The rate of racemization of nicotinamides could be controlled based on the temperature and solvent properties, and that of the salts was prolonged compared to free nicotinamides, as the molecular structure of the pyridinium ion in the salts was different from that of acid-free nicotinamides.

  5. Hygroscopic behavior of atmospheric aerosols containing nitrate salts and water-soluble organic acids

    Science.gov (United States)

    Jing, Bo; Wang, Zhen; Tan, Fang; Guo, Yucong; Tong, Shengrui; Wang, Weigang; Zhang, Yunhong; Ge, Maofa

    2018-04-01

    While nitrate salts have critical impacts on environmental effects of atmospheric aerosols, the effects of coexisting species on hygroscopicity of nitrate salts remain uncertain. The hygroscopic behaviors of nitrate salt aerosols (NH4NO3, NaNO3, Ca(NO3)2) and their internal mixtures with water-soluble organic acids were determined using a hygroscopicity tandem differential mobility analyzer (HTDMA). The nitrate salt / organic acid mixed aerosols exhibit varying phase behavior and hygroscopic growth depending upon the type of components in the particles. Whereas pure nitrate salt particles show continuous water uptake with increasing relative humidity (RH), the deliquescence transition is still observed for ammonium nitrate particles internally mixed with organic acids such as oxalic acid and succinic acid with a high deliquescence point. The hygroscopicity of submicron aerosols containing sodium nitrate and an organic acid is also characterized by continuous growth, indicating that sodium nitrate tends to exist in a liquid-like state under dry conditions. It is observed that in contrast to the pure components, the water uptake is hindered at low and moderate RH for calcium nitrate particles containing malonic acid or phthalic acid, suggesting the potential effects of mass transfer limitation in highly viscous mixed systems. Our findings improve fundamental understanding of the phase behavior and water uptake of nitrate-salt-containing aerosols in the atmospheric environment.

  6. Effects of salicylic acid on wheat salt sensitivity | Erdal | African ...

    African Journals Online (AJOL)

    In this study, investigations on the effects of foliar-applied SA on salt sensitivity, hydrogen peroxide (H2O2) generation and activities of antioxidant enzymes like peroxidase (POX) and catalase (CAT) in plant tissues under salt stress was performed. SA treatment significantly increased the fresh and dry weights in both root ...

  7. 76 FR 47146 - Citric Acid and Certain Citrate Salts From the People's Republic of China: Extension of Time...

    Science.gov (United States)

    2011-08-04

    ... DEPARTMENT OF COMMERCE International Trade Administration [A-570-937] Citric Acid and Certain... review of the antidumping duty order on citric acid and certain citrate salts (``citric acid'') from the... of citric acid from the PRC. See Citric Acid and Certain Citrate Salts From the People's Republic of...

  8. Case Studies in Systems Chemistry. Final Report. [Includes Complete Case Study, Carboxylic Acid Equilibria

    Science.gov (United States)

    Fleck, George

    This publication was produced as a teaching tool for college chemistry. The book is a text for a computer-based unit on the chemistry of acid-base titrations, and is designed for use with FORTRAN or BASIC computer systems, and with a programmable electronic calculator, in a variety of educational settings. The text attempts to present computer…

  9. Atmospheric chemistry of perfluorinated carboxylic acids: Reaction with OH radicals and atmospheric lifetimes

    DEFF Research Database (Denmark)

    Hurley, MD; Andersen, Mads Peter Sulbæk; Wallington, TJ

    2004-01-01

    Relative rate techniques were used to study the kinetics of the reactions of OH radicals with a homologous series of perfluorinated acids, F(CF2)(n)COOH (n = 1, 2, 3, 4), in 700 Torr of air at 296 +/- 2 K. For n > 1, the length of the F(CF2)(n) group had no discernible impact on the reactivity of...

  10. 78 FR 34648 - Citric Acid and Certain Citrate Salts: Preliminary Results of Countervailing Duty Administrative...

    Science.gov (United States)

    2013-06-10

    ... citric acid and citrate salts from the People's Republic of China for the period January 1, 2011, through... and Certain Citrate Salts from the People's Republic of China: Notice of Countervailing Duty Order, 74... subsidy, i.e., a government-provided financial contribution that gives rise to a benefit to the recipient...

  11. The effects of ascorbic acid on salt induced alfalfa (Medicago sativa L.)

    African Journals Online (AJOL)

    Dr. J. T. Ekanem

    contribute to the high electrical conductivity of salt-affected lands3. ... the cellular mechanisms of the stress and its application at the .... Fig 2: Effect of salt and ascorbic acid on a) stem length, b) root length, c) root number, d) dry weight of ...

  12. A study of solvent extraction of uranium and thorium with a crown either carboxylic acid

    International Nuclear Information System (INIS)

    Du Hongshan

    1995-03-01

    The solvent extraction of uranium and thorium with a new type of extractant sym-dibenzo-16-crown-5-oxyacetic acid in chloroform has been studied. The extraction efficiencies for both elements depend strongly on pH. At pH 3.5, UO 2 2+ is not extractable, whereas Th 4+ is extracted with greater than 98% efficiency. The dependence of the distribution ratios of UO 2 2+ and Th 4+ on the concentration of sym-dibenzo-16-crown-5-oxyacetic acid are linear and the slopes are 1 and 2 respectively. The results suggest that uranium and thorium appear to form a 1 : 1 and 1 : 2 extraction complex with ligand. A new method for separating U and Th is established, and U and Th with high purity can be obtained. This method have important application to analytical chemistry and nuclear industry. (8 refs., 3 figs.)

  13. Simplified method for gravimetric determination of zirconium or hafnium with α-hydroxy carboxylic acids

    International Nuclear Information System (INIS)

    Barbieri, R.S.; Rocha, J.C.; Terra, V.R.; Marques Netto, A.

    1989-01-01

    The conditions for gravimetric determination of zirconium or hafnium by glicoloc acids derivatives were studied by thermogravimetric analysis. The method utilized shownd that after precipitation, washing and drying of precipitates at 150 o C, the resulting solid was weighed in the form of [M (RCH(OH)COO) 4 ] (M = Zr, Hf; R + C 6 H 5 , β-C 10 H 7 , p-BrC 6 H 4 ). (author)

  14. Two multi-dimensional frameworks constructed from zinc coordination polymers with pyridine carboxylic acids

    International Nuclear Information System (INIS)

    Guo Yuanyuan; Ma Pengtao; Wang Jingping; Niu Jingyang

    2011-01-01

    Two novel zinc coordination polymers [Zn 2 (H 2 O)L(MoO 4 )] n (1) and [Zn 4 (PO 4 ) 2 L'(H 2 O)] n (2) (H 2 L=2,2'-bipyridine-6.6'-dicarboxylic acid, H 2 L'=2,2'-bipyridine-4,4'-dicarboxylic acid) have been hydrothermally synthesized and characterized by elemental analyses, IR spectra, UV spectra, single-crystal X-ray diffraction and thermogravimetric analyses. Structural analyses indicate that 1 represents a 2-D sheet structure built by dimeric [Zn 2 L(H 2 O)] 2+ units and MoO 4 2- groups whereas 2 displays an interesting 3-D framework constructed by tetranuclear zinc clusters, L' 2- ligands and PO 4 3- groups. Examination of UV spectra suggests that both 1 and 2 can stably exist in the pH range of 2.45-5.45 and 3.01-8.55 in aqueous solution, respectively. The room-temperature solid-state photoluminescence of 1 and 2 are derived from the intra-ligands π-π* transitions of H 2 L and H 2 L' ligands and the ligand-to-metal-charge-transfer transitions. - Graphical Abstract: Two new transition metal coordination polymers, namely, [Zn 2 (H 2 O)L 1 (MoO 4 )] n (1), [Zn 4 (PO 4 ) 2 L 2 (H 2 O)] n (2) (H 2 L 1 =2,2'-bipyridine-6,6'-dicarboxylic acid, H 2 L 2 =2,2'-bipyridine-4,4'-dicarboxylic acid) have been hydrothermally synthesized. 1 represents a 2-D sheet structure while 2 represents 3-D network. Highlights: →Two new transition metal coordination polymers have been hydrothermally synthesized. → The two compounds have been characterized by elemental analyses, IR, UV spectra, single-crystal X-ray diffraction, thermogravimetric analyses and photoluminescence. → Compound 1 represents a 2-D sheet structure while 2 represents 3-D network.

  15. Actions of a proline analogue, L-thiazolidine-4-carboxylic acid (T4C, on Trypanosoma cruzi.

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    Anahí Magdaleno

    Full Text Available It is well established that L-proline has several roles in the biology of trypanosomatids. In Trypanosoma cruzi, the etiological agent of Chagas' disease, this amino acid is involved in energy metabolism, differentiation processes and resistance to osmotic stress. In this study, we analyzed the effects of interfering with L-proline metabolism on the viability and on other aspects of the T. cruzi life cycle using the proline analogue L- thiazolidine-4-carboxylic acid (T4C. The growth of epimastigotes was evaluated using different concentrations of T4C in standard culture conditions and at high temperature or acidic pH. We also evaluated possible interactions of this analogue with stress conditions such as those produced by nutrient starvation and oxidative stress. T4C showed a dose-response effect on epimastigote growth (IC(50 = 0.89+/-0.02 mM at 28 degrees C, and the inhibitory effect of this analogue was synergistic (p<0.05 with temperature (0.54+/-0.01 mM at 37 degrees C. T4C significantly diminished parasite survival (p<0.05 in combination with nutrient starvation and oxidative stress conditions. Pre-incubation of the parasites with L-proline resulted in a protective effect against oxidative stress, but this was not seen in the presence of the drug. Finally, the trypomastigote bursting from infected mammalian cells was evaluated and found to be inhibited by up to 56% when cells were treated with non-toxic concentrations of T4C (between 1 and 10 mM. All these data together suggest that T4C could be an interesting therapeutic drug if combined with others that affect, for example, oxidative stress. The data also support the participation of proline metabolism in the resistance to oxidative stress.

  16. Bile Salt and Acid Tolerant of Lactic Acid Bacteria Isolated from Proventriculus of Broiler Chicken

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    E. Damayanti

    2014-08-01

    Full Text Available The aim of this research was to obtain the lactic acid bacteria (LAB as probiotic candidates which have resistance to bile salt and acid condition. LAB was obtained using isolation method from proventriculus of broiler chicken. Selective MRS media with 0.2% CaCO3 addition were used for LAB isolation using pour plate sampling method under anaerobic condition. The result showed that four selected isolates had morphological and biochemical characteristics as LAB. The selected LAB was characterized as follow: antibacterial activities, antibiotic sensitivity, resistance on bile salt, gastric juice and acid condition, and biochemical identification. Antibacterial activities assay of cell free supernatant was confirmed using disc paper diffusion method which was arranged on factorial design and each treatment consisted of three replications. The cell free supernatant of LAB isolates had antibacterial activities against Escherichia coli, Pseudomonas aerugenosa, and Salmonella pullorum. Molecular identification procedure using 16S rRNA sequence analysis showed that R01 and R02 as Pediococcus acidilactici. The viability of the two isolates were tested by acid pH (pH 1, 2, and 3, gastric juice pH 2, and bile salt condition for digestives tract simulation. The result showed that R01 and R02 had a high viability percentages at pH 1, 2, and 3 (95.45%, 99.49%, 104.01%, and 67.17%, 120.74%, 103.4%, respectively and at bile salt simulation for 1-2 hours (100.35%-102.71% and 100.02%-102.65%, respectively, but at gastric juice simulation for 1-2 hours, the P. acidilactici R01 had higher viability than P. acidilactici R02 (59.69%-76.53% versus 43.57%-40.69%, respectively. In the antibiotic sensitivity test for three antibiotics (i.e. erythromicin 15 µg, penicillin G 10 µg, and streptomycin 10 µg, the P. acidilactici R02 showed resistance to Streptomycin and Penicillin. It is concluded that P. acidilactici R01 and P. acidilactici R02 isolated from proventriculus

  17. Antimicrobial Activity of Fatty Acid Salts Against Microbial in Koji-Muro

    Directory of Open Access Journals (Sweden)

    Tanaka Aya

    2016-01-01

    Full Text Available Aspergillus niger and Aspergillus oryzae are used as koji fungi in the spot of the brewing. Since koji-muro (room for making koji was a low level of airtightness, microbial contamination has long been a concern to the alcoholic beverage production. Therefore, we focused on the fatty acid salt which is the main component of soap. Fatty acid salts have been reported to show some antibacterial and antifungal activity. This study aimed to find the effectiveness of the fatty acid salt in koji-muro. Nine fatty acid salts were tested. The result, C12K was antibacterial effect against B. subtilis. C10K and C12K was antifungal effect against R. oryzae. These results suggest C12K has potential in the field of koji-muro.

  18. In situ SERS and X-ray photoelectron spectroscopy studies on the pH-dependant adsorption of anthraquinone-2-carboxylic acid on silver electrode

    Energy Technology Data Exchange (ETDEWEB)

    Li, Dan, E-mail: dany@sit.edu.cn [School of Chemical and Environmental Engineering, Shanghai Institute of Technology, 100 Haiquan Road, Shanghai 201418 (China); Jia, Shaojie [School of Chemical and Environmental Engineering, Shanghai Institute of Technology, 100 Haiquan Road, Shanghai 201418 (China); Fodjo, Essy Kouadio [Laboratory of Physical Chemistry, University Felix Houphouet Boigny, 22 BP 582, Abidjan 22, Cote d’Ivoire (Cote d' Ivoire); Xu, Hu [School of Chemical and Environmental Engineering, Shanghai Institute of Technology, 100 Haiquan Road, Shanghai 201418 (China); Wang, Yuhong, E-mail: yuhong_wang502@sit.edu.cn [School of Chemical and Environmental Engineering, Shanghai Institute of Technology, 100 Haiquan Road, Shanghai 201418 (China); Deng, Wei [School of Chemical and Environmental Engineering, Shanghai Institute of Technology, 100 Haiquan Road, Shanghai 201418 (China)

    2016-03-30

    Graphical abstract: The orientation of anthraquinone-2-carboxylic acid (AQ-2-COOH) has been investigated by in situ surface-enhanced Raman scattering (in situ SERS) spectroelectrochemistry and angle-resolved X-ray photoelectron spectroscopy (AR-XPS) on silver surface. - Highlights: • The adsorption behavior of anthraquinone-2-carboxylic acid (AQ-2-COOH) on Ag electrode is influenced by the pH. • The pH-dependant adsorption of AQ-2-COOH has been confirmed by in situ surface-enhanced Raman scattering (in situ SERS) spectroelectrochemistry and angle-resolved X-ray photoelectron spectroscopy (AR-XPS). • The results can provide insights into electron transfer reactions of AQ-2-COOH in biological systems. - Abstract: In this study, in situ surface-enhanced Raman scattering (SERS) spectroelectrochemistry and angle-resolved X-ray photoelectron spectroscopy (AR-XPS) are used to investigate the redox reaction and adsorption behavior of anthraquinone-2-carboxylic acid (AQ-2-COOH) on an Ag electrode at different pH values. The obtained results indicate that AQ-2-COOH is adsorbed tilted on the Ag electrode through O-atom of ring carbonyl in a potential range from −0.3 to −0.5 V vs. SCE, but the orientation turns to more tilted orientation with both O-atom of the ring carbonyl and carboxylate group in positive potential region for pH 6.0 and 7.4. However, at pH 10.0, the orientation adopts tilted conformation constantly on the Ag electrode with both O-atom of the anthraquinone ring and carboxylate group in the potential range from −0.3 to −0.5 V vs. SCE or at positive potentials. Moreover, the adsorption behavior of AQ-2-COOH has been further confirmed by AR-XPS on the Ag surface. Proposed reasons for the observed changes in orientation are presented.

  19. Various causes behind the desorption hysteresis of carboxylic acids on mudstones.

    Science.gov (United States)

    Rasamimanana, S; Lefèvre, G; Dagnelie, R V H

    2017-02-01

    Adsorption desorption is a key factor for leaching, migration and (bio)degradation of organic pollutants in soils and sediments. Desorption hysteresis of apolar organic compounds is known to be correlated with adsorption/diffusion into soil organic matter. This work focuses on the desorption hysteresis of polar organic compounds on a natural mudstone sample. Acetic, citric and ortho-phthalic acids displayed adsorption-desorption hysteresis on Callovo-Oxfordian mudstone. The non-reversible behaviours resulted from three different mechanisms. Adsorption and desorption kinetics were evaluated using 14C- and 3H-labelled tracers and an isotopic exchange method. The solid-liquid distribution ratio of acetate decreased using a NaN 3 bactericide, indicating a rapid bacterial consumption compared with negligible adsorption. The desorption hysteresis of phthalate was apparent and suppressed by the equilibration of renewal pore water with mudstone. This confirms the significant and reversible adsorption of phthalate. Finally, persistent desorption hysteresis was evidenced for citrate. In this case, a third mechanism should be considered, such as the incorporation of citrate in the solid or a chemical perturbation, leading to strong desorption resilience. The results highlighted the different pathways that polar organic pollutants might encounter in a similar environment. Data on phthalic acid is useful to predict the retarded transport of phthalate esters and amines degradation products in sediments. The behaviour of citric acid is representative of polydentate chelating agents used in ore and remediation industries. The impact of irreversible adsorption on solid/solution partitioning and transport deserves further investigation. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Effect of alkali metal ions on the pyrrole and pyridine π-electron systems in pyrrole-2-carboxylate and pyridine-2-carboxylate molecules: FT-IR, FT-Raman, NMR and theoretical studies

    Science.gov (United States)

    Świderski, G.; Wojtulewski, S.; Kalinowska, M.; Świsłocka, R.; Lewandowski, W.

    2011-05-01

    The FT-IR, FT-Raman and 1H and 13C NMR spectra of pyrrole-2-carboxylic acid (PCA) and lithium, sodium, potassium, rubidium and caesium pyrrole-2-carboxylates were recorded, assigned and compared in the Li → Na → K → Rb → Cs salt series. The effect of alkali metal ions on the electronic system of ligands was discussed. The obtained results were compared with previously reported ones for pyridine-2-carboxylic acid and alkali metal pyridine-2-carboxylates. Calculations for pyrrole-2-carboxylic acid and Li, Na, K pyrrole-2-carboxylates in B3LYP/6-311++G ** level and Møller-Plesset method in MP2/6-311++G ** level were made. Bond lengths, angles and dipole moments as well as aromaticity indices (HOMA, EN, GEO, I 6) for the optimized structures of pyrrole-2-carboxylic acid (PCA) and lithium, sodium, potassium pyrrole-2-carboxylates were also calculated. The degree of perturbation of the aromatic system of ligand under the influence of metals in the Li → Cs series was investigated with the use of statistical methods (linear correlation), calculated aromaticity indices and Mulliken, NBO and ChelpG population analysis method. Additionally, the Bader theory (AIM) was applied to setting the characteristic of the bond critical points what confirmed the influence of alkali metals on the pyrrole ring.

  1. Functionalization and Chemical Modification of 2-Hydroxyethyl Methacrylate with Carboxylic Acid

    Directory of Open Access Journals (Sweden)

    Mohammad Hossein Nasirtabrizi

    2012-01-01

    Full Text Available Free radical polymerization of the resulting monomers methyl methacrylate (MMA, ethyl methacrylate (EMA, methylacrylate (MA and ethylacrylate (EA with 2-hydroxyethyl methacrylate (HEMA (in 1:1 mole ratio were carried out using azobis(isoboutyronitrile (AIBN as initiator at the temperature ranges 60-70°C. The modification of polymers were carried out by 9-anthracenecarboxylic acid (9-ACA via the esterification reaction between —OH of poly(HEMA and —COOH of 9-ACA, in presence of N,N′-dicyclohexyl-carbodiimide (DCC, 4-(dimethylamino pyridine (DMAP and N,N-dimethyl formamid (DMF. It was found that the molar ratio acid/alcohol/catalysts= 0.02: 0.02: 0.02 and 0.002, optimal for preparation of the ester. As demonstrated by FT-IR, 1H-NMR and dynamic mechanical thermal analysis (DMTA. The Tg value of methacrylate and acrylate copolymers containing 9-ACA groups was found to increase with incorporation of 9-ACA groups in polymer structures. The presence of 9-ACA groups in the polymer side chains created new polymers with novel modified properties that find some applications in polymer industry. These anthracenic factors could take part in cyclo addition reaction with other factors such as anhydrides and kinons.

  2. Transcriptomic and Physiological Evidence for the Relationship between Unsaturated Fatty Acid and Salt Stress in Peanut.

    Science.gov (United States)

    Sui, Na; Wang, Yu; Liu, Shanshan; Yang, Zhen; Wang, Fang; Wan, Shubo

    2018-01-01

    Peanut ( Arachis hypogaea L.) is one of the five major oilseed crops cultivated worldwide. Salt stress is a common adverse condition for the growth of this crop in many countries and regions. In this study, physiological parameters and transcriptome profiles of peanut seedlings exposed to salt stress (250 mM NaCl for 4 days, S4) and recovery for 3 days (when transferred to standard conditions for 3 days, R3) were analyzed to detect genes associated with salt stress and recovery in peanut. We observed that the quantum yield of PSII electron transport (ΦPSII) and the maximal photochemical efficiency of PSII ( F v / F m ) decreased in S4 compared with the control, and increased in R3 compared with those in S4. Seedling fresh weight, dry weight and PSI oxidoreductive activity (Δ I / I o ) were inhibited in S4 and did not recover in R3. Superoxide dismutase (SOD) and ascorbate peroxidase (APX) activities decreased in S4 and increased in R3, whereas superoxide anion ([Formula: see text]) and hydrogen peroxide (H 2 O 2 ) contents increased in S4 and decreased in R3. Transcriptome analysis revealed 1,742 differentially expressed genes (DEGs) under salt stress and 390 DEGs under recovery. Among these DEGs, two DEGs encoding ω-3 fatty acid desaturase that synthesized linolenic acid (18:3) from linoleic acid (18:2) were down-regulated in S4 and up-regulated in R3. Furthermore, ω-3 fatty acid desaturase activity decreased under salt stress and increased under recovery. Consistent with this result, 18:3 content decreased under salt stress and increased under recovery compared with that under salt treatment. In conclusion, salt stress markedly changed the activity of ω-3 fatty acid desaturase and fatty acid composition. The findings provide novel insights for the improvement of salt tolerance in peanut.

  3. The Effect of Phenazine-1-Carboxylic Acid on Mycelial Growth of Botrytis cinerea Produced by Pseudomonas aeruginosa LV Strain

    Directory of Open Access Journals (Sweden)

    Ane S. Simionato

    2017-06-01

    Full Text Available One of the most important postharvest plant pathogens that affect strawberries, grapes and tomatoes is Botrytis cinerea, known as gray mold. The fungus remains in latent form until spore germination conditions are good, making infection control difficult, causing great losses in the whole production chain. This study aimed to purify and identify phenazine-1-carboxylic acid (PCA produced by the Pseudomonas aeruginosa LV strain and to determine its antifungal activity against B. cinerea. The compounds produced were extracted with dichloromethane and passed through a chromatographic process. The purity level of PCA was determined by reversed-phase high-performance liquid chromatography semi-preparative. The structure of PCA was confirmed by nuclear magnetic resonance and electrospray ionization mass spectrometry. Antifungal activity was determined by the dry paper disk and minimum inhibitory concentration (MIC methods and identified by scanning electron microscopy and confocal microscopy. The results showed that PCA inhibited mycelial growth, where MIC was 25 μg mL-1. Microscopic analysis revealed a reduction in exopolysaccharide (EPS formation, showing distorted and damaged hyphae of B. cinerea. The results suggested that PCA has a high potential in the control of B. cinerea and inhibition of EPS (important virulence factor. This natural compound is a potential alternative to postharvest control of gray mold disease.

  4. A Molecular docking study to predict enantioseparation of some chiral carboxylic acid derivatives by methyl-β-cyclodextrin

    Science.gov (United States)

    Nurhidayah, E. S.; Ivansyah, A. L.; Martoprawiro, M. A.; Zulfikar, M. A.

    2018-05-01

    A molecular docking study, using molecular mechanics calculations with Arguslab, was used to help predict the enantioseparation of some guest molecules of chiral carboxylic acid derivatives by heptakis-2,6-di-O-methyl-β-cyclodextrin (DIMEB) and heptakis-2,3,6-tri-O-methyl-β-cyclodextrin (TRIMEB) as host molecules. The small differences in the binding free energy values (ΔΔG) obtained from Arguslab did not indicate any significant enantioseparation. From the molecular docking simulation results, it is predicted that in the case of DIMEB as host molecule, R-enantiomer of Etodolac, Fenoprofen, Indoprofen, Ketorolac, and Naproxen will be eluted first than S-enantiomer; However, S-enantiomer of Carprofen, Flurbiprofen, Ketoprofen, Pirprofen, Proglumide, Sulindac, Surprofen, and Zaltoprofen will be eluted first than R-enantiomer by DIMEB as host molecule. When TRIMEB is used as a host molecule, R-enantiomer of Carprofen, Flurbiprofen, Indoprofen, Ketoprofen, Naproxen, Pirprofen, and Surprofen will be eluted first than S-enantiomer; However, S-enantiomer of Etodolac, Fenoprofen, Ketorolac, Proglumide, Sulindac and Zaltoprofen will be eluted first than R-enantiomer by TRIMEB as host molecule.

  5. Di- and tri-carboxylic-acid-based etches for processing high temperature superconducting thin films and related materials

    International Nuclear Information System (INIS)

    Ginley, D.S.; Barr, L.; Ashby, C.I.H.; Plut, T.A.; Urea, D.; Siegal, M.P.; Martens, J.S.; Johansson, M.E.

    1994-01-01

    The development of passive and active electronics from high-temperature superconducting thin films depends on the development of process technology capable of producing appropriate feature sizes without degrading the key superconducting properties. We present a new class of chelating etches based on di- and tri-carboxylic acids that are compatible with positive photoresists and can produce sub-micron feature sizes while typically producing increases the microwave surface resistance at 94 GHz by less than 10%. This simple etching process works well for both the Y--Ba--Cu--O and Tl--Ba--Ca--Cu--O systems. In addition, we demonstrate that the use of chelating etches with an activator such as HF allows the etching of related oxides such as LaAlO 3 , which is a key substrate material, and Pb(Zr 0.53 Ti 0.47 )O 3 (PZT) which is a key ferroelectric material for HTS and other applications such as nonvolatile memories

  6. The Cytotoxicity of Benzaldehyde Nitrogen Mustard-2-Pyridine Carboxylic Acid Hydrazone Being Involved in Topoisomerase IIα Inhibition

    Directory of Open Access Journals (Sweden)

    Yun Fu

    2014-01-01

    Full Text Available The antitumor property of iron chelators and aromatic nitrogen mustard derivatives has been well documented. Combination of the two pharmacophores in one molecule in drug designation is worth to be explored. We reported previously the syntheses and preliminary cytotoxicity evaluation of benzaldehyde nitrogen mustard pyridine carboxyl acid hydrazones (BNMPH as extended study, more tumor cell lines (IC50 for HepG2: 26.1 ± 3.5 μM , HCT-116: 57.5 ± 5.3 μM, K562: 48.2 ± 4.0 μM, and PC-12: 19.4 ± 2.2 μM were used to investigate its cytotoxicity and potential mechanism. In vitro experimental data showed that the BNMPH chelating Fe2+ caused a large number of ROS formations which led to DNA cleavage, and this was further supported by comet assay, implying that ROS might be involved in the cytotoxicity of BNMPH. The ROS induced changes of apoptosis related genes, but the TFR1 and NDRG1 metastatic genes were not obviously regulated, prompting that BNMPH might not be able to deprive Fe2+ of ribonucleotide reductase. The BNMPH induced S phase arrest was different from that of iron chelators (G1 and alkylating agents (G2. BNMPH also exhibited its inhibition of human topoisomerase IIα. Those revealed that the cytotoxic mechanism of the BNMPH could stem from both the topoisomerase II inhibition, ROS generation and DNA alkylation.

  7. Effectiveness of 5-Pyrrolidone-2-carboxylic Acid and Copper Sulfate Pentahydrate Association against Drug Resistant Staphylococcus Strains.

    Science.gov (United States)

    Governa, Paolo; Miraldi, Elisabetta; De Fina, Gianna; Biagi, Marco

    2016-04-01

    Bacterial resistance is an ongoing challenge for pharmacotherapy and pharmaceutical chemistry. Staphylococcus aureus is the bacterial species which makes it most difficult to treat skin and soft tissue infections and it is seen in thousands of hospitalization cases each year. Severe but often underrated infectious diseases, such as complicated nasal infections, are primarily caused by MRSA and S. epidermidis too. With the aim of studying new drugs with antimicrobial activity and effectiveness on drug resistant Staphylococcus strains, our attention in this study was drawn on the activity of a new association between two natural products: 5-pyrrolidone-2-carboxylic acid (PCA), naturally produced by certain Lactobacillus species, and copper sulfate pentahydrate (CS). The antimicrobial susceptibility test was conducted taking into account 12 different Staphylococcus strains, comprising 6 clinical isolates and 6 resistant strains. PCA 4%, w/w, and CS 0.002%, w/w, association in distilled water solution was found to have bactericidal activity against all tested strains. Antimicrobial kinetics highlighted that PCA 4%, w/w, and CS 0.002% association could reduce by 5 log10 viable bacterial counts of MRSA and oxacillin resistant S. epidennidis in less than 5 and 3 minutes respectively. Microscopic investigations suggest a cell wall targeting mechanism of action. Being very safe and highly tolerated, the natural product PCA and CS association proved to be a promising antimicrobial agent to treat Staphylococcus related infections.

  8. Kinetin Enhanced 1-Aminocyclopropane-1-Carboxylic Acid Utilization during Alleviation of High Temperatures Stress in Lettuce Seeds.

    Science.gov (United States)

    Khan, A A; Prusinski, J

    1989-10-01

    The thermoinhibition at 35 and 32 degrees C of pregermination ethylene production and germination in lettuce (Lactuca sativa L. cv Mesa 659) seeds was synergistically or additively alleviated by 0.05 millimolar kinetin (KIN) and 10 millimolar 1-aminocyclopropane-1-carboxylic acid (ACC). The synergistic effect of KIN + ACC on ethylene production and germination at 35 degrees C was inhibited by Co(2+) (44-46%) but not by aminoethoxyvinyl glycine (AVG). The uptake of ACC by the seed was not influenced by KIN. Upon slitting of the seed coats (composed of pericarp, testa and endosperm), following the uptake of chemicals, ACC was readily converted into ethylene at all temperatures, and the synergistic effects of KIN + ACC at 35 degrees C were lost. At 35 degrees C, KIN acted synergistically with ACC or ethephon (ETH) in alleviating the osmotic restraint. At 25 degrees C, ETH was more active than KIN or KIN + ACC in overcoming the osmotic restraint. Thus, the integrity of the seed coats, the KIN-enhanced ACC utilization, and an interaction of KIN with the ethylene produced may be the basis for the synergistic or additive effects of KIN + ACC at high temperature.

  9. Solvent extraction of uranium(VI) and thorium(IV) from nitrate media by carboxylic acid amides

    International Nuclear Information System (INIS)

    Preston, J.S.; Preez, A.C. du

    1995-01-01

    A series of nineteen N-alkyl carboxylic acid amides (R.CO.NHR') has been prepared, in which the alkyl groups R and R' have been varied in order to introduce different degrees of steric complexity into the compounds. A smaller number of N,N-dialkyl amides (R.CO.NR 2 ') and non-substituted amides (R.CO.NH 2 ) has also been prepared for comparison purposes. These amides were characterized by measurement of their boiling points, melting points, refractive indices and densities. The solvent extraction of uranium(VI) and thorium(IV) from sodium nitrate media by solutions of the amides in toluene was studied. Increasing steric bulk of the alkyl groups R and R' was found to cause a marked decrease in the extraction of thorium, with a much smaller effect on the extraction of uranium, thus considerably enhancing the separation between these metals. Vapour pressure osmometry studies indicate that the N-alkyl amides are self-associated in toluene solution, with aggregation numbers up to about 2.5 for 0.6 M solutions at 35 degree C. In contrast, the N,N-dialkyl amides behave as monomers under these conditions. The distribution ratios for the extraction of uranium and thorium show second- and third-order dependences, respectively, on the extractant concentration for both the N-alkyl and N,N-dialkyl amides. 15 refs., 8 figs., 8 tabs

  10. Meso-ester and carboxylic acid substituted BODIPYs with far-red and near-infrared emission for bioimaging applications

    KAUST Repository

    Ni, Yong

    2014-01-21

    A series of meso-ester-substituted BODIPY derivatives 1-6 are synthesized and characterized. In particular, dyes functionalized with oligo(ethylene glycol) ether styryl or naphthalene vinylene groups at the α positions of the BODIPY core (3-6) become partially soluble in water, and their absorptions and emissions are located in the far-red or near-infrared region. Three synthetic approaches are attempted to access the meso-carboxylic acid (COOH)-substituted BODIPYs 7 and 8 from the meso-ester-substituted BODIPYs. Two feasible synthetic routes are developed successfully, including one short route with only three steps. The meso-COOH-substituted BODIPY 7 is completely soluble in pure water, and its fluorescence maximum reaches around 650 nm with a fluorescence quantum yield of up to 15 %. Time-dependent density functional theory calculations are conducted to understand the structure-optical properties relationship, and it is revealed that the Stokes shift is dependent mainly on the geometric change from the ground state to the first excited singlet state. Furthermore, cell staining tests demonstrate that the meso-ester-substituted BODIPYs (1 and 3-6) and one of the meso-COOH-substituted BODIPYs (8) are very membrane-permeable. These features make these meso-ester- and meso-COOH-substituted BODIPY dyes attractive for bioimaging and biolabeling applications in living cells. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. 4D-Qsar Study of Some Pyrazole Pyridine Carboxylic Acid Derivatives by Electron Conformational-Genetic Algorithm Method.

    Science.gov (United States)

    Tuzun, Burak; Yavuz, Sevtap Caglar; Sabanci, Nazmiye; Saripinar, Emin

    2018-05-13

    In the present work, pharmacophore identification and biological activity prediction for 86 pyrazole pyridine carboxylic acid derivatives were made using the electron conformational genetic algorithm approach which was introduced as a 4D-QSAR analysis by us in recent years. In the light of the data obtained from quantum chemical calculations at HF/6-311 G** level, the electron conformational matrices of congruity (ECMC) were constructed by EMRE software. Comparing the matrices, electron conformational submatrix of activity (ECSA, Pha) was revealed that are common for these compounds within a minimum tolerance. A parameter pool was generated considering the obtained pharmacophore. To determine the theoretical biological activity of molecules and identify the best subset of variables affecting bioactivities, we used the nonlinear least square regression method and genetic algorithm. The results obtained in this study are in good agreement with the experimental data presented in the literature. The model for training and test sets attained by the optimum 12 parameters gave highly satisfactory results with R2training= 0.889, q2=0.839 and SEtraining=0.066, q2ext1 = 0.770, q2ext2 = 0.750, q2ext3=0.824, ccctr = 0.941, ccctest = 0.869 and cccall = 0.927. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  12. Determination of the conformation of 2-hydroxy- and 2-aminobenzoic acid dimers using 13C NMR and density functional theory/natural bond order analysis: the central importance of the carboxylic acid carbon.

    Science.gov (United States)

    Burnette, Ronald R; Weinhold, Frank

    2006-07-20

    The 13C chemical shift for the carboxylic acid carbon provides a powerful diagnostic probe to determine the preferred isomeric dimer structures of benzoic acid derivatives undergoing intra- and intermolecular H-bonding in the gas, solution and crystalline phases. We have employed hybrid density functional calculations and natural bond orbital analysis to elucidate the electronic origins of the observed 13C shieldings and their relationship to isomeric stability. We find that delocalizing interactions from the carbonyl oxygen lone pairs (nO) into vicinal carbon-oxygen and carbon-carbon antibonds (sigmaCO*,sigmaCC*) make critical contributions to the 13C shieldings, and these nO --> sigmaCO*, nO --> sigmaCC* interactions are in turn sensitive to the intramolecular interactions that dictate dimer structure and stability. The carboxyl carbon atom can thus serve as a useful detector of subtle structural and conformational features in this pharmacologically important class of carboxylic acid interactions.

  13. Binding of cyclic carboxylates to octa-acid deep-cavity cavitand

    Science.gov (United States)

    Gibb, Corinne L. D.; Gibb, Bruce C.

    2014-04-01

    As part of the fourth statistical assessment of modeling of proteins and ligands (sampl.eyesopen.com) prediction challenge, the strength of association of nine guests ( 1- 9) binding to octa-acid host was determined by a combination of 1H NMR and isothermal titration calorimetry. Association constants in sodium tetraborate buffered (pH 9.2) aqueous solution ranged from 5.39 × 102 M-1 in the case of benzoate 1, up to 3.82 × 105 M-1 for trans-4-methylcyclohexanoate 7. Overall, the free energy difference between the free energies of complexation of these weakest and strongest binding guests was ΔΔG° = 3.88 kcal mol-1. Based on a multitude of previous studies, the anticipated order of strength of binding was close to that which was actually obtained. However, the binding of guest 3 (4-ethylbenzoate) was considerably stronger than initially estimated.

  14. Hygroscopic behavior of atmospheric aerosols containing nitrate salts and water-soluble organic acids

    Directory of Open Access Journals (Sweden)

    B. Jing

    2018-04-01

    Full Text Available While nitrate salts have critical impacts on environmental effects of atmospheric aerosols, the effects of coexisting species on hygroscopicity of nitrate salts remain uncertain. The hygroscopic behaviors of nitrate salt aerosols (NH4NO3, NaNO3, Ca(NO32 and their internal mixtures with water-soluble organic acids were determined using a hygroscopicity tandem differential mobility analyzer (HTDMA. The nitrate salt ∕ organic acid mixed aerosols exhibit varying phase behavior and hygroscopic growth depending upon the type of components in the particles. Whereas pure nitrate salt particles show continuous water uptake with increasing relative humidity (RH, the deliquescence transition is still observed for ammonium nitrate particles internally mixed with organic acids such as oxalic acid and succinic acid with a high deliquescence point. The hygroscopicity of submicron aerosols containing sodium nitrate and an organic acid is also characterized by continuous growth, indicating that sodium nitrate tends to exist in a liquid-like state under dry conditions. It is observed that in contrast to the pure components, the water uptake is hindered at low and moderate RH for calcium nitrate particles containing malonic acid or phthalic acid, suggesting the potential effects of mass transfer limitation in highly viscous mixed systems. Our findings improve fundamental understanding of the phase behavior and water uptake of nitrate-salt-containing aerosols in the atmospheric environment.

  15. Solvothermal synthesis of uranium(VI) phases with aromatic carboxylate ligands: A dinuclear complex with 4-hydroxybenzoic acid and a 3D framework with terephthalic acid

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yingjie, E-mail: yzx@ansto.gov.au [Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, NSW 2232 (Australia); Karatchevtseva, Inna [Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, NSW 2232 (Australia); Bhadbhade, Mohan [Mark Wainwright Analytical Centre, University of New South Wales, Kensington, NSW 2052 (Australia); Tran, Toan Trong; Aharonovich, Igor [School of Physics and Advanced Materials, University of Technology Sydney, Ultimo, NSW 2007 (Australia); Fanna, Daniel J.; Shepherd, Nicholas D. [School of Science and Health, Western Sydney University, Locked Bag 1797, Penrith, NSW 2751 (Australia); Lu, Kim [Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, NSW 2232 (Australia); Li, Feng [School of Science and Health, Western Sydney University, Locked Bag 1797, Penrith, NSW 2751 (Australia); Lumpkin, Gregory R. [Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, NSW 2232 (Australia)

    2016-02-15

    With the coordination of dimethylformamide (DMF), two new uranium(VI) complexes with either 4-hydroxybenzoic acid (H{sub 2}phb) or terephthalic acid (H{sub 2}tph) have been synthesized under solvothermal conditions and structurally characterized. [(UO{sub 2}){sub 2}(Hphb){sub 2}(phb)(DMF)(H{sub 2}O){sub 3}]·4H{sub 2}O (1) has a dinuclear structure constructed with both pentagonal and hexagonal bipyramidal uranium polyhedra linked through a µ{sub 2}-bridging ligand via both chelating carboxylate arm and alcohol oxygen bonding, first observation of such a coordination mode of 4-hydroxybenzoate for 5 f ions. [(UO{sub 2})(tph)(DMF)] (2) has a three-dimensional (3D) framework built with pentagonal bipyramidal uranium polyhedra linked with µ{sub 4}-terephthalate ligands. The 3D channeled structure is facilitated by the unique carboxylate bonding with nearly linear C–O–U angles and the coordination of DMF molecules. The presence of phb ligands in different coordination modes, uranyl ions in diverse environments and DMF in complex 1, and tph ligand, DMF and uranyl ion in complex 2 has been confirmed by Raman spectroscopy. In addition, their thermal stability and photoluminescence properties have been investigated. - Graphical abstract: With the coordination of dimethylformamide, two new uranyl complexes with either 4-hydroxybenzoate or terephthalate have been synthesized under solvothermal conditions and structurally characterized. - Highlights: • Solvent facilitates the synthesis of two new uranium(VI) complexes. • A dinuclear complex with both penta- and hexagonal bipyramidal uranium polyhedral. • A unique µ{sub 2}-bridging mode of 4-hydroxybenzoate via alcohol oxygen for 5 f ions. • A 3D framework with uranium polyhedra and µ{sub 4}-terephthalate ligands. • Vibration modes and photoluminescence properties are reported.

  16. Luminescent hybrid lanthanide sulfates and lanthanide sulfonate-carboxylates with 1,10-phenanthroline involving in-situ oxidation of 2-mercaptonbenzoic acid

    International Nuclear Information System (INIS)

    Zhong, Jie-Cen; Wan, Fang; Sun, Yan-Qiong; Chen, Yi-Ping

    2015-01-01

    A series of lanthanide sulfates and lanthanide sulfonate-carboxylates, [Ln 2 (phen) 2 (SO 4 ) 3 (H 2 O) 2 ] n (I:Ln=Nd(1a), Sm(1b), Eu(1c), phen=1,10-phenanthroline) and [Ln(phen)(2-SBA)(BZA)] n (II: Ln=Sm(2a), Eu(2b), Dy(2c), 2-SBA=2-sulfobenzoate, BZA=benzoate) have been hydrothermally synthesized from lanthanide oxide, 2-mercaptonbenzoic acid with phen as auxiliary ligand and characterized by single-crystal X-ray diffraction, elemental analyses, IR spectra, TG analyses and luminescence spectroscopy. Interestingly, SO 4 2− anions in I came from the in situ deep oxidation of thiol groups of 2-mercaptonbenzoic acid while 2-sulfobenzoate and benzoate ligands in II from the middle oxidation and desulfuration reactions of 2-mercaptonbenzoic acid. Compounds I are organic–inorganic hybrid lanthanide sulfates, which have rare one-dimensional column-like structures. Complexes II are binuclear lanthanide sulfonate-carboxylates with 2-sulfobenzoate and benzoate as bridges and 1,10-phenanthroline as terminal. Photoluminescence studies reveal that complexes I and II exhibit strong lanthanide characteristic emission bands in the solid state at room temperature. - Graphical abstract: Lanthanide sulfates and lanthanide sulfonate-carboxylates have been hydrothermally synthesized. Interestingly, sulfate anions, 2-sulfobenzoate and benzoate ligands came from the in situ oxidation and desulfuration reactions of 2-mercaptonbenzoic acid. - Highlights: • In situ oxidation and desulfuration reactions of 2-mercaptonbenzoic acid. • The organic–inorganic hybrid lanthanide sulfates with one-dimensional column-like structure. • The dinuclear lanthanide sulfonate-carboxylates. • The emission spectra exhibit the characteristic transition of 5 D 0 → 7 F J (J=0–4) of the Eu(III)

  17. Pre-sowing application of ascorbic acid and salicylic acid to seed of pumpkin and seedling response to salt

    International Nuclear Information System (INIS)

    Rafique, N.; Raza, S.H.; Qasim, M.; Iqbal, N.

    2011-01-01

    The effects of seed soaking with salicylic acid or ascorbic acid on pumpkin seedlings growth under saline (10 dS m/sup -1/) conditions were investigated. Seedlings fresh weight, protein contents, protease and nitrate reductase activities were significantly affected by 15 and 30 mg L/sup -1/ salicylic acid and 30 mg L/sup -1/ ascorbic acid priming treatments, under both normal and saline conditions. Priming reduced the severity of the salt stress, the amelioration was better due to 30 mg L/sup -1/ ascorbic acid or 30 mg L/sup -1/ salicylic acid treatments as these treatments showed best results on seedling growth, fresh and dry matter production under non-saline and saline environments. Application of seed priming with ascorbic acid and salicylic acid in pumpkin ameliorate the adverse effects of salt stress. (author)

  18. Method for the determination of carboxylic acids in industrial effluents using dispersive liquid-liquid microextraction with injection port derivatization gas chromatography-mass spectrometry.

    Science.gov (United States)

    Makoś, Patrycja; Fernandes, Andre; Boczkaj, Grzegorz

    2017-09-29

    The paper presents a new method for the determination of 15 carboxylic acids in samples of postoxidative effluents from the production of petroleum bitumens using ion-pair dispersive liquid-liquid microextraction and gas chromatography coupled to mass spectrometry with injection port derivatization. Several parameters related to the extraction and derivatization efficiency were optimized. Under optimized experimental conditions, the obtained limit of detection and quantification ranged from 0.0069 to 1.12μg/mL and 0.014 to 2.24μg/mL, respectively. The precision (RSD ranged 1.29-6.42%) and recovery (69.43-125.79%) were satisfactory. Nine carboxylic acids at concentrations ranging from 0.10μg/mL to 15.06μg/mL were determined in the raw wastewater and in samples of effluents treated by various oxidation methods. The studies revealed a substantial increase of concentration of benzoic acids, in samples of wastewater after treatment, which confirms the need of carboxylic acids monitoring during industrial effluent treatment processes. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Development and Validation of an HPLC Method for Simultaneous Quantification of Clopidogrel Bisulfate, Its Carboxylic Acid Metabolite, and Atorvastatin in Human Plasma: Application to a Pharmacokinetic Study

    Directory of Open Access Journals (Sweden)

    Octavian Croitoru

    2015-01-01

    Full Text Available A simple, sensitive, and specific reversed phase liquid chromatographic method was developed and validated for simultaneous quantification of clopidogrel, its carboxylic acid metabolite, and atorvastatin in human serum. Plasma samples were deproteinized with acetonitrile and ibuprofen was chosen as internal standard. Chromatographic separation was performed on an BDS Hypersil C18 column (250 × 4.6 mm; 5 μm via gradient elution with mobile phase consisting of 10 mM phosphoric acid (sodium buffer solution (pH = 2.6 adjusted with 85% orthophosphoric acid : acetonitrile : methanol with flow rate of 1 mL·min−1. Detection was achieved with PDA detector at 220 nm. The method was validated in terms of linearity, sensitivity, precision, accuracy, limit of quantification, and stability tests. Calibration curves of the analytes were found to be linear in the range of 0.008–2 μg·mL−1 for clopidogrel, 0.01–4 μg·mL−1 for its carboxylic acid metabolite, and 0.005–2.5 μg·mL−1 for atorvastatin. The results of accuracy (as recovery with ibuprofen as internal standard were in the range of 96–98% for clopidogrel, 94–98% for its carboxylic acid metabolite, and 90–99% for atorvastatin, respectively.

  20. High fluorescence emission of carboxylic acid functionalized polystyrene/BaTiO{sub 3} nanocomposites and rare earth metal complexes: Preparation and characterization

    Energy Technology Data Exchange (ETDEWEB)

    Cao, X. T.; Showkat, A. M.; Wang, Z.; Lim, K. T., E-mail: ktlim@pknu.ac.kr [Department of Imaging System Engineering, Pukyong National University, Busan 608-737 (Korea, Republic of)

    2015-03-30

    Noble fluorescence nanocomposite compound based on barium titanate nanoparticles (BTO), polystyrene (PSt), and terbium ion (Tb{sup 3+}) was synthesized by a combination of surface-initiated reversible addition-fragmentation chain transfer (RAFT) polymerization, Friedel-Crafts alkylation reaction and coordinate chemistry. Initially, a modification of surface of BTO was conducted by an exchange process with S-benzyl S’-trimethoxysilylpropyltrithiocarbonate to create macro-initiator for polymerization of styrene. Subsequently, aryl carboxylic acid functionalized polystyrene grafted barium titanate (BTO-g-PSt-COOH) was generated by substitution reaction between 4-(Chloromethyl) benzoic acid and PSt chains. The coordination of the nanohybrids with Tb{sup 3+} ions afforded fluorescent Tb{sup 3+} tagged aryl carboxylic acid functionalized polystyrene grafted barium titanate (BTO-g-PSt-Tb{sup 3+}) complexes. Structure, morphology, and fluorescence properties of nanohybrid complexes were investigated by respective physical and spectral studies. FT-IR and SEM analyses confirmed the formation of BTO-g-PSt-Tb{sup 3+}nanohybrids. Furthermore, TGA profiles demonstrated the grafting of aryl carboxylic acid functionalized polystyrene on BTO surface. Optical properties of BTO-g-PSt-Tb{sup 3+} complexes were investigated by fluorescence spectroscopy.

  1. Dynamic flow method to study the CO2 loading capacity of amino acid salt solutions

    DEFF Research Database (Denmark)

    Lerche, Benedicte Mai; Stenby, Erling Halfdan; Thomsen, Kaj

    Due to a number of advantages amino acid salt solutions have emerged as alternatives to the alkanolamine solvents for the chemical absorption of CO2 from flue gas. The use of amino acids in CO2 capture is a bio-mimetic process, as it is similar to CO2 binding by proteins in the blood......, such as hemoglobin. Amino acid salt solutions have the same amine functionality as alkanolamines, and are thus expected to behave similar towards CO2 in flue gas. Despite rising interest, few studies have been performed so far on amino acids as CO2 absorbents....

  2. Synthesis, characterization and crystal structure of (2RS,4R)-2-(2-hydroxy-3-methoxyphenyl)thiazolidine-4-carboxylic acid

    Science.gov (United States)

    Muche, Simon; Müller, Matthias; Hołyńska, Małgorzata

    2018-03-01

    The condensation reaction of ortho-vanillin and L-cysteine leads to formation of a racemic mixture of (2RS,4R)-2-(2-hydroxy-3-methoxyphenyl)thiazolidine-4-carboxylic acid and not, as reported in the available literature, to a Schiff base. The racemic mixture was fully characterized by 1D and 2D NMR techniques, ESI-MS and X-ray diffraction. Addition of ZnCl2 led to formation of crystals in form of colorless needles, suitable for X-ray diffraction studies. The measured crystals were identified as the diastereomer (2R,4R)-2-(2-hydroxy-3-methoxyphenyl)thiazolidine-4-carboxylic acid 1. The bulk material is racemic. Thiazolidine exists as zwitterion in solid state, as indicated by the crystal structure.

  3. Effects of humic acid and solution chemistry on the aggregation and dispersion of carboxyl-functionalized carbon black nanoparticles

    Science.gov (United States)

    Hwang, G.; Gomez-Flores, A.; Choi, S.; Han, Y., , Dr; Kim, H.

    2017-12-01

    The influence of humic acid, ionic strength and ionic species on the aggregation and dispersion of carboxyl-functionalized carbon black nanoparticles (CB-NPs) was systemically investigated in aqueous media. The experimental conditions of stability tests were selected to the changes in the solution chemistry (0.1-10 mM NaCl and 0.01-1 mM CaCl2) and in the presence/absence of humic acid (1 and 5 mg L-1) in an aquatic environment. The CB-NPs suspension was more rapidly settled in NaCl solution than in CaCl2. Specifically, in the case of NaCl, the aggregation rate of CB-NPs increased with ionic strength. Contrary, CB-NPs dispersed in CaCl2 were insensitive to the aggregation as the ionic strength increased; that was because specific adsorption of the divalent cation Ca2+ occurred since the zeta potential of the CB-NPs is reversed to a positive charge with increasing of the ionic strength. It was confirmed that humic acid greatly influences the stability of the CB-NPs. In particular, the dispersion of CB-NPs was improved in the whole range of ionic strengths of NaCl as well as of CaCl2. To support the results, the interaction energy between CB-NPs was calculated for each condition by using the classical Derjaguin-Landau-Verwey-Overbeek (DLVO) and modified-DLVO theories. In the presence of humic acid, the improved stability of CB-NPs is attributed to the steric repulsive force.This research was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (NRF-2015R1D1A3A01020766), the Ministry of Education (MOE) and National Research Foundation of Korea (NRF) through the Human Resource Training Project for Regional Innovation (2015H1C1A1035930) and Korea Energy and Mineral Resources Engineering Program (KEMREP).

  4. Amino acid salt solutions as solvents in CO2 capture from flue gas

    DEFF Research Database (Denmark)

    Lerche, Benedicte Mai; Thomsen, Kaj; Stenby, Erling Halfdan

    New solvents based on the salts of amino acids have emerged as an alternative to the alkanolamine solutions, for the chemical absorption of CO2 from flue gas. But only few studies on amino acids as CO2 capturing agents have been performed so far. One of the interesting features of amino acid salt...... solutions is their ability to form solid precipitates upon the absorption of CO2. The occurrence of crystallization offers the possibility of increasing the CO2 loading capacity of the solvent. However, precipitation can also have negative effect on the CO2 capture process. The chemical nature of the solid...... of glycine, taurine, and lysine, while in the case of proline, and glutamic acid, the precipitate was found to be bicarbonate. These results give an important contribution to further understanding the potential of amino acid salt solutions in CO2 capture from flue gas....

  5. Synthesis, structural, solubility and anticancer activity studies of salts using nucleobases and sulfonic acids coformer

    Science.gov (United States)

    Singh, Neetu; Singh, Udai P.; Nikhil, Kumar; Roy, Partha; Singh, Hariji

    2017-10-01

    The reactions of natural and unnatural nucleobases (cytosine (Cyt), adenine (Ade), 5-aminouracil (AU) and caffeine (Caff)) with sulfonic acids coformer (1,5-naphthalenedisulfonic acid, NDSA; 5-sulfosalicylic acid, SSA) resulted in the formation of salts viz. [NDSA.Cyt] (1), [NDSA.Ade] (2), [NDSA.AU] (3), [NDSA.Caff] (4), [SSA.Cyt] (5), [SSA.Ade] (6), [SSA.AU] (7), and [SSA.Caff] (8). The structural analysis revealed that salts 1, 4, 6 and 7 have intermolecular interactions between adjacent nucleobases which form two different homodimer shown in R22 (8) motif and assembled via complementary Nsbnd H⋯O and Nsbnd H⋯N interactions. However, in all other salts an intermediate supramolecular synthon pattern was observed between nucleobases and sulfonic acids. The lattice energy was also calculated by DFT to investigate whether salts were thermodynamically more stable than its coformer. The same was further confirmed by differential scanning calorimetry-thermogravimetric (DSC-TG) analysis. The anticancer activity study of individual nucleobases and their NDSA salts were also performed on human breast (MCF-7) and lung (A 549) cancer cell. The salts formation of nucleobases with sulfonic acids improved their solubility, thereby demonstrating up to 8-fold increase in solubility of nucleobases.

  6. Determination of carboxylic acids, carbohydrates and metals in different tomato cultivars by HPLC-ICP-AES in a single chromatographic run

    OpenAIRE

    Paredes Paredes, Eduardo; Maestre, Salvador E.; Prats Moya, Soledad; Todolí Torró, José Luis

    2007-01-01

    Póster presentado en European Winter Conference on Plasma Spectrochemistry 2007, 18-23 February 2007, Taormina, Italy The determination of carbohydrates, carboxylic acids and metals is a subject of great interest in the field of food science because their presence and concentration can influence on food quality. Besides the study of the profiles of these compounds can permit the discrimination between different varieties of a product. Unfortunately, the usually employed chromatograph...

  7. A library synthesis of 4-hydroxy-3-methyl-6-phenylbenzofuran-2-carboxylic acid ethyl ester derivatives as anti-tumor agents.

    Science.gov (United States)

    Hayakawa, Ichiro; Shioya, Rieko; Agatsuma, Toshinori; Furukawa, Hidehiko; Naruto, Shunji; Sugano, Yuichi

    2004-09-06

    As a result of a hit-to-lead program using a technique of solution-phase parallel synthesis, a highly potent (2,4-dimethoxyphenyl)-[6-(3-fluorophenyl)-4-hydroxy-3-methylbenzofuran-2-yl]methanone (15b) was synthesized as an optimized derivative of 4-hydroxy-3-methyl-6-phenylbenzofuran-2-carboxylic acid ethyl ester (1), which was discovered as a screening hit from small-molecule libraries and exhibited selective cytotoxicity against a tumorigenic cell line.

  8. HISTOPATHOLOGICAL EFFECTS OF (4S)-2-(4-HYDROXY-3-METHOXYPHENYL) THIAZOLIDINE-4-CARBOXYLIC ACID ON ZEBRAFISH (Danio rerio) HEART TISSUE

    OpenAIRE

    YÖN, Nazan Deniz; ÖZTÜRK, Burcu; ZENGİN, Mustafa; AKBULUT, Cansu

    2018-01-01

    Examination thehistopathological effects of (4s)-2-(4-hydroxy-3-methoxyphenyl) thiazolidine-4-carboxylicacid on heart tissue of zebrafish were aimed.Introduction:(4S)-2-(4-hydroxy-3-methoxyphenyl) thiazolidine-4-carboxylic acid is newsynthesized substance which obtained from cysteine and valine. Because ofthiazolidine derivates have important biological responses scientist workintensively on these compounds recent years. It is obvious that thiazolidinecontained compounds will be used in futur...

  9. Cofactor Balance by Nicotinamide Nucleotide Transhydrogenase (NNT) Coordinates Reductive Carboxylation and Glucose Catabolism in the Tricarboxylic Acid (TCA) Cycle*♦

    Science.gov (United States)

    Gameiro, Paulo A.; Laviolette, Laura A.; Kelleher, Joanne K.; Iliopoulos, Othon; Stephanopoulos, Gregory

    2013-01-01

    Cancer and proliferating cells exhibit an increased demand for glutamine-derived carbons to support anabolic processes. In addition, reductive carboxylation of α-ketoglutarate by isocitrate dehydrogenase 1 (IDH1) and 2 (IDH2) was recently shown to be a major source of citrate synthesis from glutamine. The role of NAD(P)H/NAD(P)+ cofactors in coordinating glucose and glutamine utilization in the tricarboxylic acid (TCA) cycle is not well understood, with the source(s) of NADPH for the reductive carboxylation reaction remaining unexplored. Nicotinamide nucleotide transhydrogenase (NNT) is a mitochondrial enzyme that transfers reducing equivalents from NADH to NADPH. Here, we show that knockdown of NNT inhibits the contribution of glutamine to the TCA cycle and activates glucose catabolism in SkMel5 melanoma cells. The increase in glucose oxidation partially occurred through pyruvate carboxylase and rendered NNT knockdown cells more sensitive to glucose deprivation. Importantly, knocking down NNT inhibits reductive carboxylation in SkMel5 and 786-O renal carcinoma cells. Overexpression of NNT is sufficient to stimulate glutamine oxidation and reductive carboxylation, whereas it inhibits glucose catabolism in the TCA cycle. These observations are supported by an impairment of the NAD(P)H/NAD(P)+ ratios. Our findings underscore the role of NNT in regulating central carbon metabolism via redox balance, calling for other mechanisms that coordinate substrate preference to maintain a functional TCA cycle. PMID:23504317

  10. Preparation of an aminopropyl imidazole-modified silica gel as a sorbent for solid-phase extraction of carboxylic acid compounds and polycyclic aromatic hydrocarbons.

    Science.gov (United States)

    Wang, Na; Guo, Yong; Wang, Licheng; Liang, Xiaojing; Liu, Shujuan; Jiang, Shengxiang

    2014-05-21

    In this paper, a kind of aminopropyl imidazole-modified silica sorbent was synthesized and used as a solid-phase extraction (SPE) sorbent for the determination of carboxylic acid compounds and polycyclic aromatic hydrocarbons (PAHs). The resultant aminopropyl imidazole-modified silica sorbent was characterized by Fourier transform infrared spectroscopy (FT-IR) and elemental analysis (EA) to ensure the successful binding of aminopropyl imidazole on the surface of silica gel. Then the aminopropyl imidazole-modified silica sorbent served as a SPE sorbent for the enrichment of carboxylic acid compounds and PAHs. The new sorbent exhibited high extraction efficiency towards the tested compounds and the results show that such a sorbent can offer multiple intermolecular interactions: electrostatic, π-π, and hydrophobic interactions. Several parameters affecting the extraction recovery, such as the pH of sample solution, the pH of eluent, the solubility of eluent, the volume of eluent, and sample loading, were also investigated. Under the optimized conditions, the proposed method was applied to the analysis of four carboxylic acid compounds and four PAHs in environmental water samples. Good linearities were obtained for all the tested compounds with R(2) larger than 0.9903. The limits of detection were found to be in the range of 0.0065-0.5 μg L(-1). The recovery values of spiked river water samples were from 63.2% to 112.3% with relative standard deviations (RSDs) less than 10.1% (n = 4).

  11. Structure-Activity Relationship Study of Ionotropic Glutamate Receptor Antagonist (2S,3R)-3-(3-Carboxyphenyl)pyrrolidine-2-carboxylic Acid

    DEFF Research Database (Denmark)

    Krogsgaard-Larsen, Niels; Storgaard, Morten; Møller, Charlotte

    2015-01-01

    Herein we describe the first structure-activity relationship study of the broad-range iGluR antagonist (2S,3R)-3-(3-carboxyphenyl)pyrrolidine-2-carboxylic acid (1) by exploring the pharmacological effect of substituents in the 4, 4', or 5' positions and the bioisosteric substitution of the distal...... carboxylic acid for a phosphonic acid moiety. Of particular interest is a hydroxyl group in the 4' position 2a which induced a preference in binding affinity for homomeric GluK3 over GluK1 (Ki = 0.87 and 4.8 μM, respectively). Two X-ray structures of ligand binding domains were obtained: 2e in GluA2-LBD...... and 2f in GluK1-LBD, both at 1.9 Å resolution. Compound 2e induces a D1-D2 domain opening in GluA2-LBD of 17.3-18.8° and 2f a domain opening in GluK1-LBD of 17.0-17.5° relative to the structures with glutamate. The pyrrolidine-2-carboxylate moiety of 2e and 2f shows a similar binding mode as kainate...

  12. An engineered fatty acid synthase combined with a carboxylic acid reductase enables de novo production of 1-octanol in Saccharomyces cerevisiae.

    Science.gov (United States)

    Henritzi, Sandra; Fischer, Manuel; Grininger, Martin; Oreb, Mislav; Boles, Eckhard

    2018-01-01

    The ideal biofuel should not only be a regenerative fuel from renewable feedstocks, but should also be compatible with the existing fuel distribution infrastructure and with normal car engines. As the so-called drop-in biofuel, the fatty alcohol 1-octanol has been described as a valuable substitute for diesel and jet fuels and has already been produced fermentatively from sugars in small amounts with engineered bacteria via reduction of thioesterase-mediated premature release of octanoic acid from fatty acid synthase or via a reversal of the β-oxidation pathway. The previously engineered short-chain acyl-CoA producing yeast Fas1 R1834K /Fas2 fatty acid synthase variant was expressed together with carboxylic acid reductase from Mycobacterium marinum and phosphopantetheinyl transferase Sfp from Bacillus subtilis in a Saccharomyces cerevisiae Δfas1 Δfas2 Δfaa2 mutant strain. With the involvement of endogenous thioesterases, alcohol dehydrogenases, and aldehyde reductases, the synthesized octanoyl-CoA was converted to 1-octanol up to a titer of 26.0 mg L -1 in a 72-h fermentation. The additional accumulation of 90 mg L -1 octanoic acid in the medium indicated a bottleneck in 1-octanol production. When octanoic acid was supplied externally to the yeast cells, it could be efficiently converted to 1-octanol indicating that re-uptake of octanoic acid across the plasma membrane is not limiting. Additional overexpression of aldehyde reductase Ahr from Escherichia coli nearly completely prevented accumulation of octanoic acid and increased 1-octanol titers up to 49.5 mg L -1 . However, in growth tests concentrations even lower than 50.0 mg L -1 turned out to be inhibitory to yeast growth. In situ extraction in a two-phase fermentation with dodecane as second phase did not improve growth, indicating that 1-octanol acts inhibitive before secretion. Furthermore, 1-octanol production was even reduced, which results from extraction of the intermediate octanoic acid to

  13. Biodistribution and human dosimetry of enantiomer-1 of the synthetic leucine analog anti-1-amino-2-fluorocyclopentyl-1-carboxylic acid

    International Nuclear Information System (INIS)

    Nye, Jonathon A.; Jarkas, Nashwa; Schuster, David M.; Savir-Baruch, Bital; Voll, Ronald J.; Camp, Vernon M.; Goodman, Mark M.

    2011-01-01

    Introduction: The enantiomerically enriched (ee=90%, enantiomer 1) synthetic amino acid (R,S)-anti-1-amino-2-fluorocyclopentyl-1-carboxylic acid (anti-2-[ 18 F]FACPC-1) accumulates in malignant cells by elevated transport through the sodium-independent system-L (leucine preferring) amino acid transporter. The purpose of this study was to evaluate in vivo uptake and single-dose toxicity of anti-2-[ 18 F]FACPC-1 in animals as well as the individual organ and whole-body dose in humans. Methods: A DU145 xenograft rodent model was used to measure anti-2-[ 18 F]FACPC-1 uptake at 15, 30 and 60 min post-injection. Animals were sacrificed and organs harvested to measure the percent injected activity per organ and to calculate residence time. Anti-2-[ 18 F]FACPC-1 toxicity was assessed using a single microdose (37-74 MBq/kg) in nonhuman primates. Their vital signs were monitored for 2 h post-injection for drug-related effects. Human biodistribution studies were collected by sequential whole-body PET/CT scans on six healthy volunteers (three male and three female) for 120 min following a single 247±61 MBq bolus injection of anti-2-[ 18 F]FACPC-1. Estimates of radiation dose from anti-2-[ 18 F]FACPC-1 to the human body were calculated using recommendations of the MIRD committee and MIRDOSE 3.0 software. Results: High anti-2-[ 18 F]FACPC-1 residence time was observed in the pancreas of the rodent model compared to the human data. No abnormal treatment-related observations were made in the nonhuman primate toxicity studies. Human venous blood showed no metabolites of anti-2-[ 18 F]FACPC-1 in the first 60 min post-injection. All volunteers showed initially high uptake in the kidneys followed by a rapid washout phase. The estimated effective dose equivalent was 0.0196 mSv/MBq. Conclusion: Anti-2-[ 18 F]FACPC-1 showed low background uptake in the brain, thoracic and abdominal cavities of humans, suggesting a possible use for detecting malignant tissues in these regions.

  14. Biodistribution and human dosimetry of enantiomer-1 of the synthetic leucine analog anti-1-amino-2-fluorocyclopentyl-1-carboxylic acid

    Energy Technology Data Exchange (ETDEWEB)

    Nye, Jonathon A., E-mail: jnye@emory.edu; Jarkas, Nashwa; Schuster, David M.; Savir-Baruch, Bital; Voll, Ronald J.; Camp, Vernon M.; Goodman, Mark M.

    2011-10-15

    Introduction: The enantiomerically enriched (ee=90%, enantiomer 1) synthetic amino acid (R,S)-anti-1-amino-2-fluorocyclopentyl-1-carboxylic acid (anti-2-[{sup 18}F]FACPC-1) accumulates in malignant cells by elevated transport through the sodium-independent system-L (leucine preferring) amino acid transporter. The purpose of this study was to evaluate in vivo uptake and single-dose toxicity of anti-2-[{sup 18}F]FACPC-1 in animals as well as the individual organ and whole-body dose in humans. Methods: A DU145 xenograft rodent model was used to measure anti-2-[{sup 18}F]FACPC-1 uptake at 15, 30 and 60 min post-injection. Animals were sacrificed and organs harvested to measure the percent injected activity per organ and to calculate residence time. Anti-2-[{sup 18}F]FACPC-1 toxicity was assessed using a single microdose (37-74 MBq/kg) in nonhuman primates. Their vital signs were monitored for 2 h post-injection for drug-related effects. Human biodistribution studies were collected by sequential whole-body PET/CT scans on six healthy volunteers (three male and three female) for 120 min following a single 247{+-}61 MBq bolus injection of anti-2-[{sup 18}F]FACPC-1. Estimates of radiation dose from anti-2-[{sup 18}F]FACPC-1 to the human body were calculated using recommendations of the MIRD committee and MIRDOSE 3.0 software. Results: High anti-2-[{sup 18}F]FACPC-1 residence time was observed in the pancreas of the rodent model compared to the human data. No abnormal treatment-related observations were made in the nonhuman primate toxicity studies. Human venous blood showed no metabolites of anti-2-[{sup 18}F]FACPC-1 in the first 60 min post-injection. All volunteers showed initially high uptake in the kidneys followed by a rapid washout phase. The estimated effective dose equivalent was 0.0196 mSv/MBq. Conclusion: Anti-2-[{sup 18}F]FACPC-1 showed low background uptake in the brain, thoracic and abdominal cavities of humans, suggesting a possible use for detecting

  15. Mitigation of Humic Acid Inhibition in Anaerobic Digestion of Cellulose by Addition of Various Salts

    Directory of Open Access Journals (Sweden)

    Samet Azman

    2015-03-01

    Full Text Available Humic compounds are inhibitory to the anaerobic hydrolysis of cellulosic biomass. In this study, the impact of salt addition to mitigate the inhibitory effects of humic compounds was investigated. The experiment was conducted using batch tests to monitor the anaerobic hydrolysis of cellulose in the presence of humic acid. Sodium, potassium, calcium, magnesium and iron salts were tested separately for their efficiency to mitigate humic acid inhibition. All experiments were done under mesophilic conditions (30 °C and at pH 7. Methane production was monitored online, using the Automatic Methane Potential Test System. Methane production, soluble chemical oxygen demand and volatile fatty acid content of the samples were measured to calculate the hydrolysis efficiencies. Addition of magnesium, calcium and iron salts clearly mitigated the inhibitory effects of humic acid and hydrolysis efficiencies reached up to 75%, 65% and 72%, respectively, which were similar to control experiments. Conversely, potassium and sodium salts addition did not mitigate the inhibition and hydrolysis efficiencies were found to be less than 40%. Mitigation of humic acid inhibition via salt addition was also validated by inductively coupled plasma atomic emission spectroscopy analyses, which showed the binding capacity of different cations to humic acid.

  16. Synthesis of a metabolically stable modified long-chain fatty acid salt and its photolabile derivative

    Energy Technology Data Exchange (ETDEWEB)

    Stoll, G.H.; Voges, R.; Gerok, W.; Kurz, G. (Institut fuer Organische Chemie and Biochemie, Universitaet Freiburg (Germany))

    1991-05-01

    An analogue of the long-chain fatty acid salt, sodium stearate, was synthesized in which the hydrogen atoms at carbons 2, 3, and 18 were replaced by fluorine. The key step in the synthesis was the addition of 3-iodo-2,2,3,3-tetrafluoropropanoic acid amide to 15,15,15-trifluoro-1-pentadecene. Radioactivity was introduced by catalytic reduction of 2,2,3,3,18,18,18-heptafluoro-4-octadecenoic acid amide with carrier-free tritium gas yielding a product with the specific radioactivity of 2.63 TBq/mmol. The resulting 2,2,3,3,18,18,18-heptafluoro-4-octadecenoic acid has a pKa of about 0.5 and is completely dissociated under normal physiological conditions. The fluorinated fatty acid salt analogue is readily taken up into hepatocytes and proved to be metabolically inert. In an approach to the identification of proteins involved in long-chain fatty acid salt transport across membranes and intracellular compartments, the photolabile derivative 11,11-azo-2,2,3,3,18,18,18-heptafluoro(G-3H)octadecanoic acid sodium salt was synthesized with a specific radioactivity of 2.63 TBq/mmol. Photolysis of the photolabile derivative, using a light source with a maximum emission at 350 nm, occurred with a half-life of 1.5 min. The generated carbene reacted with 14C-labeled methanol and acetonitrile with covalent bond formation of 6-13%. Its efficacy for photoaffinity labeling was demonstrated by incorporation into serum albumin, the extracellular fatty acid salt-binding protein, as well as into the intracellular fatty acid salt-binding protein (FABP) of rat liver with the molecular weight of 14,000.

  17. 1-Azaniumylcyclobutane-1-carboxylate monohydrate

    Directory of Open Access Journals (Sweden)

    Ray J. Butcher

    2014-02-01

    Full Text Available In the title compound, C5H9NO2·H2O, the amino acid is in the usual zwitterionic form involving the α-carboxylate group. The cyclobutane backbone of the amino acid is disordered over two conformations, with occupancies of 0.882 (7 and 0.118 (7. In the crystal, N—H...O and O—H...O hydrogen bonds link the zwitterions [with the water molecule involved as both acceptor (with the NH3+ and donor (through a single carboxylate O from two different aminocyclobutane carboxylate moities], resulting in a two-dimensional layered structure lying parallel to (100.

  18. 75 FR 14082 - Ammonium Salts of Fatty Acids (C8

    Science.gov (United States)

    2010-03-24

    ... component of the mammalian diet and the body is able to metabolize these soap salts and use them as an energy source. Due to the self-limiting nature of these chemicals (e.g. unpleasant taste and odor... study showed no adverse effect of treatment on clinical signs, body weights, weight gain, or food/water...

  19. 40 CFR 721.1650 - Alkylbenzenesulfonic acid and sodium salts.

    Science.gov (United States)

    2010-07-01

    ... information on methods for protecting against such risk, into an MSDS as described in § 721.72(c) within 90... salts. 721.1650 Section 721.1650 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... substance is any manner or method of manufacture, import, or processing associated with any use of this...

  20. 40 CFR 721.6140 - Dialkyldithiophosphoric acid, aliphatic amine salt.

    Science.gov (United States)

    2010-07-01

    ... methods for protecting against such risk, into an MSDS as described in § 721.72(c) within 90 days from the..., aliphatic amine salt. 721.6140 Section 721.6140 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... manner or method of manufacture, import, or processing associated with any use of this substance without...

  1. Cyanide toxicokinetics: the behavior of cyanide, thiocyanate and 2-amino-2-thiazoline-4-carboxylic acid in multiple animal models.

    Science.gov (United States)

    Bhandari, Raj K; Oda, Robert P; Petrikovics, Ilona; Thompson, David E; Brenner, Matthew; Mahon, Sari B; Bebarta, Vikhyat S; Rockwood, Gary A; Logue, Brian A

    2014-05-01

    Cyanide causes toxic effects by inhibiting cytochrome c oxidase, resulting in cellular hypoxia and cytotoxic anoxia, and can eventually lead to death. Cyanide exposure can be verified by direct analysis of cyanide concentrations or analyzing its metabolites, including thiocyanate (SCN(-)) and 2-amino-2-thiazoline-4-carboxylic acid (ATCA) in blood. To determine the behavior of these markers following cyanide exposure, a toxicokinetics study was performed in three animal models: (i) rats (250-300 g), (ii) rabbits (3.5-4.2 kg) and (iii) swine (47-54 kg). Cyanide reached a maximum in blood and declined rapidly in each animal model as it was absorbed, distributed, metabolized and eliminated. Thiocyanate concentrations rose more slowly as cyanide was enzymatically converted to SCN(-). Concentrations of ATCA did not rise significantly above the baseline in the rat model, but rose quickly in rabbits (up to a 40-fold increase) and swine (up to a 3-fold increase) and then fell rapidly, generally following the relative behavior of cyanide. Rats were administered cyanide subcutaneously and the apparent half-life (t1/2) was determined to be 1,510 min. Rabbits were administered cyanide intravenously and the t1/2 was determined to be 177 min. Swine were administered cyanide intravenously and the t1/2 was determined to be 26.9 min. The SCN(-) t1/2 in rats was 3,010 min, but was not calculated in rabbits and swine because SCN(-) concentrations did not reach a maximum. The t1/2 of ATCA was 40.7 and 13.9 min in rabbits and swine, respectively, while it could not be determined in rats with confidence. The current study suggests that cyanide exposure may be verified shortly after exposure by determining significantly elevated cyanide and SCN(-) in each animal model and ATCA may be used when the ATCA detoxification pathway is significant.

  2. Quinolinic Carboxylic Acid Derivatives as Potential Multi-target Compounds for Neurodegeneration: Monoamine Oxidase and Cholinesterase Inhibition.

    Science.gov (United States)

    Khan, Nehal A; Khan, Imtiaz; Abid, Syed M A; Zaib, Sumera; Ibrar, Aliya; Andleeb, Hina; Hameed, Shahid; Iqbal, Jamshed

    2018-01-01

    Parkinson's disease (PD), a debilitating and progressive disorder, is among the most challenging and devastating neurodegenerative diseases predominantly affecting the people over 60 years of age. To confront PD, an advanced and operational strategy is to design single chemical functionality able to control more than one target instantaneously. In this endeavor, for the exploration of new and efficient inhibitors of Parkinson's disease, we synthesized a series of quinoline carboxylic acids (3a-j) and evaluated their in vitro monoamine oxidase and cholinesterase inhibitory activities. The molecular docking and in silico studies of the most potent inhibitors were performed to identify the probable binding modes in the active site of the monoamine oxidase enzymes. Moreover, molecular properties were calculated to evaluate the druglikeness of the compounds. The biological evaluation results revealed that the tested compounds were highly potent against monoamine oxidase (A & B), 3c targeted both the isoforms of MAO with IC50 values of 0.51 ± 0.12 and 0.51 ± 0.03 µM, respectively. The tested compounds also demonstrated high and completely selective inhibitory action against acetylcholinesterase (AChE) with IC50 values ranging from 4.36 to 89.24 µM. Among the examined derivatives, 3i was recognized as the most potent inhibitor of AChE with an IC50 value of 4.36 ± 0.12 ±µM. The compounds appear to be promising inhibitors and could be used for the future development of drugs targeting neurodegenerative disorders. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  3. Inhibition studies of soybean (Glycine max) urease with heavy metals, sodium salts of mineral acids, boric acid, and boronic acids.

    Science.gov (United States)

    Kumar, Sandeep; Kayastha, Arvind M

    2010-10-01

    Various inhibitors were tested for their inhibitory effects on soybean urease. The K(i) values for boric acid, 4-bromophenylboronic acid, butylboronic acid, and phenylboronic acid were 0.20 +/- 0.05 mM, 0.22 +/- 0.04 mM, 1.50 +/- 0.10 mM, and 2.00 +/- 0.11 mM, respectively. The inhibition was competitive type with boric acid and boronic acids. Heavy metal ions including Ag(+), Hg(2+), and Cu(2+) showed strong inhibition on soybean urease, with the silver ion being a potent inhibitor (IC(50) = 2.3 x 10(-8) mM). Time-dependent inhibition studies exhibited biphasic kinetics with all heavy metal ions. Furthermore, inhibition studies with sodium salts of mineral acids (NaF, NaCl, NaNO(3), and Na(2)SO(4)) showed that only F(-) inhibited soybean urease significantly (IC(50) = 2.9 mM). Competitive type of inhibition was observed for this anion with a K(i) value of 1.30 mM.

  4. Investigations of the sorption of pertechnetate on salts of molybdophosphoric acid

    International Nuclear Information System (INIS)

    Suess, M.; Pfrepper, G.

    1983-01-01

    Studies were made to investigate the sorption of pertechnetate on neutral and acid salts of molybdophosphoric acid from nitric acid and in the presence of electrolytes and non-electrolytes. Particular, distribution coefficients from 10 to 100 were found. The sorption of pertechnetate can be increased by the addition of K + , NH 4 + , Rb + and Cs + salts, by the addition of non-electrolytes the distribution coefficients decrease. A saturation capacity of about 0.19 mmol Tc/g ammonium phosphomolybdate was determined from the adsorption isotherms. The formation of alkali metal pertechnetate associates in the sorbent phase can be supposed. (author)

  5. 40 CFR 721.3820 - L-Glutamic acid, N-(1-oxododecyl)-, disodium salt.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false L-Glutamic acid, N-(1-oxododecyl... Specific Chemical Substances § 721.3820 L-Glutamic acid, N-(1-oxododecyl)-, disodium salt. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as L-Glutamic...

  6. In vitro salt stress induced production of gymnemic acid in callus ...

    African Journals Online (AJOL)

    ... is presented in this investigation. The highest efficiency of callus formation was observed in the medium containing different concentrations of 2,4-D. The gymnemic acid content increased with increasing concentration of 2,4-D along with NaCl. Key words: In vitro, Gymnema sylvestre, callus culture, gymnemic acid, salt ...

  7. Crystal structures of seven molecular salts derived from benzylamine and organic acidic components

    Science.gov (United States)

    Wen, Xianhong; Jin, Xiunan; Lv, Chengcai; Jin, Shouwen; Zheng, Xiuqing; Liu, Bin; Wang, Daqi; Guo, Ming; Xu, Weiqiang

    2017-07-01

    Cocrystallization of the commonly available organic amine, benzylamine, with a series of organic acids gave a total of seven molecular salts with the compositions: (benzylamine): (p-toluenesulfonic acid) (1) [(HL)+ · (tsa-)], (benzylamine): (o-nitrobenzoic acid) (2) [(HL+) · (onba)-], (benzylamine): (3,4-methylenedioxybenzoic acid) (3) [(HL+) · (mdba-)], (benzylamine): (mandelic acid) (4) [(HL+) · (mda-)], (benzylamine): (5-bromosalicylic acid)2(5) [(HL+) · (bsac-) · (Hbsac)], (benzylamine): (m-phthalic acid) (6) [(HL+) · (Hmpta-)], and (benzylamine)2: (trimesic acid) (7) [(HL+)2 · (Htma2-)]. The seven salts have been characterised by X-ray diffraction technique, IR, and elemental analysis, and the melting points of all the salts were also reported. And their structural and supramolecular aspects are fully analyzed. The result reveals that among the seven investigated crystals the NH2 groups in the benzylamine moieties are protonated when the organic acids are deprotonated, and the crystal packing is interpreted in terms of the strong charge-assisted Nsbnd H⋯O hydrogen bond formation between the ammonium and the deprotonated acidic groups. Except the Nsbnd H⋯O hydrogen bond, the Osbnd H⋯O hydrogen bonds (charge assisted or neutral) were also found at the salts 4-7. Further analysis of the crystal packing of the salts indicated that a different family of additional CHsbnd O/CH2sbnd O, CHsbnd π/CH2sbnd π, Osbnd O, and Osbnd Cπ associations contribute to the stabilization and expansion of the total high-dimensional (2D-3D) framework structures. For the coexistence of the various weak nonbonding interactions these structures adopted homo or hetero supramolecular synthons or both. Some classical supramolecular synthons, such as R42(8), R43(10) and R44(12), usually observed in organic solids of organic acids with amine, were again shown to be involved in constructing most of these hydrogen bonding networks.

  8. On the microstructure of organic solutions of mono-carboxylic acids: Combined study by infrared spectroscopy, small-angle neutron scattering and molecular dynamics simulations

    Energy Technology Data Exchange (ETDEWEB)

    Eremin, Roman A., E-mail: era@jinr.ru [Joint Institute for Nuclear Research, Dubna 141980 (Russian Federation); Kholmurodov, Kholmirzo T. [Joint Institute for Nuclear Research, Dubna 141980 (Russian Federation); International University “Dubna”, Dubna 141980 (Russian Federation); Petrenko, Viktor I. [Joint Institute for Nuclear Research, Dubna 141980 (Russian Federation); Taras Shevchenko National University of Kyiv, Kyiv 03022 (Ukraine); Rosta, László [Wigner Research Centre for Physics, Hungarian Academy of Sciences, Budapest H-1525 (Hungary); Grigoryeva, Natalia A. [Faculty of Physics, Saint-Petersburg State University, 198504 Saint-Petersburg (Russian Federation); Avdeev, Mikhail V. [Joint Institute for Nuclear Research, Dubna 141980 (Russian Federation)

    2015-11-05

    Highlights: • The model of the scattering particle for a reliable SANS analysis is proposed. • The structural parameters of saturated mono-carboxylic acids in solutions are obtained. • The differences in nematic transitions correlate to solvation peculiarities. - Abstract: The data of infrared spectroscopy (IR), molecular dynamics (MD) simulations and small-angle neutron scattering (SANS) have been combined to conclude about the nanoscale structural organization of organic non-polar solutions of saturated mono-carboxylic acids with different alkyl chain lengths for diluted solutions of saturated myristic (C14) and stearic (C18) acids in benzene and decalin. In particular, the degree of dimerization was found from the IR spectra. The structural anisotropy of the acids and their dimers was used in the treatment of the data of MD simulations to describe the solute–solvent interface in a cylindrical approximation and show its rather strong influence on SANS. The corresponding scattering length density profiles were used to fit the experimental SANS data comprising the information about the acid molecule isomerization. The SANS data from concentrated solutions showed a partial self-assembling of the acids within the nematic transition is different for two solvents due to lyophobic peculiarities.

  9. Gas chromatographic-mass spectrometric investigation of n-alkanes and carboxylic acids in bottom sediments of the northern Caspian Sea

    Science.gov (United States)

    Kenzhegaliev, Akimgali; Zhumagaliev, Sagat; Kenzhegalieva, Dina; Orazbayev, Batyr

    2018-03-01

    Prior to the start of experimental oil production in the Kashagan field (northern part of the Caspian Sea), n-alkanes and carboxylic acids contained in samples obtained from bottom sediments in the area of artificial island "D" were investigated by gas chromatography-mass spectrometry. Concentrations of 10 n-alkanes (composed of C10-C13, C15-C20) and 11 carboxylic acids (composed of C6-C12, C14-C16) were identified and measured. Concentrations of individual alkanes and carboxylic acids in bottom sediments of the various samples varied between 0.001 ÷ 0.88 μg/g and 0.001 ÷ 1.94 μg/g, respectively. Mass spectra, in particular the M+ molecular ion peak and the most intense peaks of fragment ions, are given. The present study illustrates the stability of molecular ions to electronic ionisation and the main fragment ions to the total ion current and shows that the initial fragmentation of alkanes implies radical cleavage of C2H5 rather than CH3. All aliphatic monocarboxylic acids studied were characterised by McLafferty rearrangement leading to the formation of F4 cation-radical with m/z 60 and F3 cation-radical with m/z 88 in the case of ethylhexanoic acid. The formation of oxonium ions presents another important aspect of acid fragmentation. Using mass numbers of oxonium ions and rearrangement ions allows determination of the substitution character in α- and β- C atoms. The essence of our approach is to estimate the infiltration of hydrocarbon fluids from the enclosing formation into sea water, comprising an analysis of derivatives of organic compounds in bottom sediments. Thus, concentrations of derived organic molecules can serve as a basis for estimates of the depth at which hydrocarbon fluids leak, i.e., to serve as an auxiliary technique in the search for hydrocarbon deposits and to repair well leaks.

  10. Reaction of uranyl nitrate with carboxylic di-acids under hydrothermal conditions. Crystal structure of complexes with L(+)-tartaric and oxalic acids

    International Nuclear Information System (INIS)

    Thuery, P.

    2007-01-01

    L(+)-tartaric acid reacts with uranyl nitrate in the presence of KOH, under mild hydrothermal conditions, to give the complex [UO 2 (C 4 H 4 O 6 )(H 2 O)] (1), the first uranyl tartrate to be crystallographically characterized. Each tartrate ligand bridges three uranyl ions, one of them in chelating fashion through proximal carboxylate and hydroxyl groups. The resulting assemblage is two-dimensional, with the uranyl pentagonal bipyramidal coordination polyhedra separated from one another. Prolonged heating of an uranyl tartrate solution resulted in oxidative cleavage of the acid and formation of the oxalate complex [(UO 2 ) 2 (C 2 O 4 ) 2 (OH)Na(H 2 O) 2 ] (2). The bis-bidentate oxalate and bridging hydroxide groups ensure the formation of sheets with corner-sharing uranyl pentagonal bipyramidal coordination polyhedra, in which six-membered metallacycles encompass the sodium ions. These sheets are assembled into a three-dimensional framework through further oxo-bonding of the sodium ions. (authors)

  11. Effects of aminoisobutyric acid on 1-aminocyclopropane-1-carboxylic acid uptake, ethylene production and content of ACC in water-stressed tomato plants

    International Nuclear Information System (INIS)

    Kalantari, Kh.M.; Bolourani, P.

    2000-01-01

    The effect of water stress on the regulation of ethylene biosynthesis has not yet clearly been established. Both the formation and utilization of aminocyclopropane-1-carboxylic acid, ACC, are considered to be major regulatory points in ethylene biosynthesis. There is evidence that ACC synthase is the key control enzyme in response to various stimuli associated with the induction of ethylene biosynthesis. It has been reported that aminoisobutyric acid, AIB, inhibits ethylene production in some plants and AIB may inhibit the conversion of ACC to ethylene. For this reason, the possibility of inhibition of ACC uptake in the presence of AIB was examined. It was observed that the rate of 14 C-ACC uptake decreased with an increase in the concentration of AIB in the solution. Calculating the percentage of ACC converted to ethylene on the basis of uptake shows that AIB inhibits the conversion of 14 C-ACC to ethylene and that this inhibition is increased with an increase in the concentration of AIB in the solution. This suggests that a portion of the inhibition of the conversion of ACC to ethylene in the presence of AIB is partly due to the competition for absorption. However, the ability of AIB to inhibit ethylene production in leaf tissue without an exogenous supply of ACC clearly indicates that AIB inhibits ethylene production. The present study was undertaken to elucidate the regulation of ethylene biosynthesis in water-stressed plants and the results are discussed

  12. Bioactivation of carboxylic acid compounds by UDP-Glucuronosyltransferases to DNA-damaging intermediates: role of glycoxidation and oxidative stress in genotoxicity.

    Science.gov (United States)

    Sallustio, Benedetta C; Degraaf, Yvette C; Weekley, Josephine S; Burcham, Philip C

    2006-05-01

    Nonenzymatic modification of proteins by acyl glucuronides is well documented; however, little is known about their potential to damage DNA. We have previously reported that clofibric acid undergoes glucuronidation-dependent bioactivation to DNA-damaging species in cultured mouse hepatocytes. The aim of this study was to investigate the mechanisms underlying such DNA damage, and to screen chemically diverse carboxylic acid drugs for their DNA-damaging potential in glucuronidation proficient murine hepatocytes. Cells were incubated with each aglycone for 18 h, followed by assessment of compound cytotoxicity using the MTT assay and evaluation of DNA damage using the Comet assay. Relative cytotoxic potencies were ketoprofen > diclofenac, benoxaprofen, nafenopin > gemfibrozil, probenecid > bezafibrate > clofibric acid. At a noncytotoxic (0.1 mM) concentration, only benoxaprofen, nafenopin, clofibric acid, and probenecid significantly increased Comet moments (P Clofibric acid and probenecid exhibited the greatest DNA-damaging potency, producing significant DNA damage at 0.01 mM concentrations. The two drugs produced maximal increases in Comet moment of 4.51 x and 2.57 x control, respectively. The glucuronidation inhibitor borneol (1 mM) abolished the induction of DNA damage by 0.5 mM concentrations of clofibric acid and probenecid. In an in vitro cell-free system, clofibric acid glucuronide was 10 x more potent than glucuronic acid in causing DNA strand-nicking, although both compounds showed similar rates of autoxidation to generate hydroxyl radicals. In cultured hepatocytes, the glycation inhibitor, aminoguanidine, and the iron chelator, desferrioxamine mesylate, inhibited DNA damage by clofibric acid, whereas the free radical scavengers Trolox and butylated hydroxytoluene, and the superoxide dismutase mimetic bis-3,5-diisopropylsalicylate had no effect. In conclusion, clinically relevant concentrations of two structurally unrelated carboxylic acids, probenecid and

  13. Discovery of a New Class of Ionotropic Glutamate Receptor Antagonists by the Rational Design of (2S,3R)-3-(3-Carboxyphenyl)-pyrrolidine-2-carboxylic Acid

    DEFF Research Database (Denmark)

    Larsen, Ann Møller; Venskutonyte, Raminta; Valadés, Elena Antón

    2011-01-01

    The kainic acid (KA) receptors belong to the class of glutamate (Glu) receptors in the brain and constitute a promising target for the treatment of neurological and/ or psychiatric diseases such as schizophrenia, major depression, and epilepsy. Five KA subtypes have been identified and named GluK1......-5. In this article, we present the discovery of (2S,3R)-3-(3-carboxyphenyl)-pyrrolidine-2-carboxylic acid (1) based on a rational design process. Target compound 1 was synthesized by a stereoselective strategy in 10 steps from commercially available starting materials. Binding affinities of 1 at native ionotropic...

  14. Enhanced electrochemical response in oxidative differential pulse voltammetry of dopamine in the presence of ascorbic acid at carboxyl-terminated boron-doped diamond electrodes

    International Nuclear Information System (INIS)

    Kondo, Takeshi; Niwano, Yu; Tamura, Akira; Imai, Junichi; Honda, Kensuke; Einaga, Yasuaki; Tryk, Donald A.; Fujishima, Akira; Kawai, Takeshi

    2009-01-01

    The differential pulse voltammetric (DPV) peak for dopamine (DA) oxidation was found to be highly amplified by the addition of ascorbic acid (AA) when carboxyl-terminated boron-doped diamond (BDD) electrodes were used as the working electrode. The DP voltammogram for a solution containing DA and AA obtained using a 4-pentenoic acid-modified BDD (4PA-BDD) electrode showed well-separated oxidation peaks for DA and AA at 0.4 and 0.6 V vs. Ag/AgCl, respectively. In addition, as the DA concentration increased at constant AA concentration, a simultaneous increase in the DA peak current density and decrease in the AA peak current density were observed. The slope of the calibration curve for the [DA] range of 1-10 μM in the presence of AA (500 μM) was seven times larger than that obtained in the absence of AA. Such an enhancement was found to be more efficient at 4PA-BDD than at oxidized-BDD, partly due to simple electrostatic effects and partly due to suppression of the polymerization of DA oxidation products by the terminal carboxyl groups. The enhanced detection method using a carboxyl-terminated BDD electrode should be an effective analytical tool, especially for determining low concentrations of DA in the presence of high concentrations of AA

  15. Enhanced electrochemical response in oxidative differential pulse voltammetry of dopamine in the presence of ascorbic acid at carboxyl-terminated boron-doped diamond electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Kondo, Takeshi [Department of Industrial Chemistry, Faculty of Engineering, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku-ku, Tokyo 162-8601 (Japan)], E-mail: t.kondo@ci.kagu.tus.ac.jp; Niwano, Yu; Tamura, Akira; Imai, Junichi [Department of Industrial Chemistry, Faculty of Engineering, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku-ku, Tokyo 162-8601 (Japan); Honda, Kensuke [Department of Chemistry and Earth Sciences, Faculty of Science, Yamaguchi University, 1677-1 Yoshida, Yamaguchi-shi, Yamaguchi 753-8521 (Japan); Einaga, Yasuaki [Department of Chemistry, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Yokohama 223-0012 (Japan); Tryk, Donald A. [Fuel Cell Nanomaterials Center, University of Yamanashi, Takeda 4-3-11, Kofu, Yamanashi 400-8511 (Japan); Fujishima, Akira [Kanagawa Academy of Science and Technology (KAST), 3-2-1 Sakado, Takatsu-ku, Kawasaki, Kanagawa 213-0012 (Japan); Kawai, Takeshi [Department of Industrial Chemistry, Faculty of Engineering, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku-ku, Tokyo 162-8601 (Japan)

    2009-03-01

    The differential pulse voltammetric (DPV) peak for dopamine (DA) oxidation was found to be highly amplified by the addition of ascorbic acid (AA) when carboxyl-terminated boron-doped diamond (BDD) electrodes were used as the working electrode. The DP voltammogram for a solution containing DA and AA obtained using a 4-pentenoic acid-modified BDD (4PA-BDD) electrode showed well-separated oxidation peaks for DA and AA at 0.4 and 0.6 V vs. Ag/AgCl, respectively. In addition, as the DA concentration increased at constant AA concentration, a simultaneous increase in the DA peak current density and decrease in the AA peak current density were observed. The slope of the calibration curve for the [DA] range of 1-10 {mu}M in the presence of AA (500 {mu}M) was seven times larger than that obtained in the absence of AA. Such an enhancement was found to be more efficient at 4PA-BDD than at oxidized-BDD, partly due to simple electrostatic effects and partly due to suppression of the polymerization of DA oxidation products by the terminal carboxyl groups. The enhanced detection method using a carboxyl-terminated BDD electrode should be an effective analytical tool, especially for determining low concentrations of DA in the presence of high concentrations of AA.

  16. 77 FR 72323 - Citric Acid and Certain Citrate Salts From the People's Republic of China: Final Results of...

    Science.gov (United States)

    2012-12-05

    ... DEPARTMENT OF COMMERCE International Trade Administration [C-570-938] Citric Acid and Certain... countervailing duty (CVD) order on citric acid and certain citrate salts from the People's Republic of China for... results of this review.\\1\\ \\1\\ See Citric Acid and Certain Citrate Salts from the People's Republic of...

  17. 76 FR 82275 - Citric Acid and Certain Citrate Salts From the People's Republic of China: Extension of Time...

    Science.gov (United States)

    2011-12-30

    ... DEPARTMENT OF COMMERCE International Trade Administration [C-570-938] Citric Acid and Certain...) published in the Federal Register the countervailing duty order on citric acid and certain citrate salts... Affirmative Countervailing Duty Determinations: Citric Acid and Certain Citrate Salts, 74 FR 25705 (May 29...

  18. 77 FR 74171 - Citric Acid and Certain Citrate Salts From the People's Republic of China: Final Results of...

    Science.gov (United States)

    2012-12-13

    ... DEPARTMENT OF COMMERCE International Trade Administration [A-570-937] Citric Acid and Certain... review of the antidumping duty order on citric acid and certain citrate salts from the People's Republic..., regarding ``Second Antidumping Administrative Review of Citric Acid and Certain Citrate Salts from the...

  19. 77 FR 56188 - Citric Acid and Certain Citrate Salts from the People's Republic of China: Notice of Rescission...

    Science.gov (United States)

    2012-09-12

    ... DEPARTMENT OF COMMERCE International Trade Administration [C-570-938] Citric Acid and Certain... (CVD) order on citric acid and certain citrate salts from the People's Republic of China.\\1\\ On [[Page...\\ See Citric Acid and Certain Citrate Salts from the People's Republic of China: Intent to Rescind...

  20. The effect of postirradiation application of aspartic acid salts on hemopoietic recovery in sublethally X-irradiated mice

    International Nuclear Information System (INIS)

    Pospisil, M.; Netikova, J.; Vasku, J.; Urbanek, E.

    1979-01-01

    The effect of aspartic acid salts, especially of K and Mg aspartates, on certain hematological changes in the peripheral blood and hemopoietic organs of sublethally X-irratiated male mice of the strain C57Bl/10 was investigated. Salts of aspartic acid were administered in tap water after irradiation. A favorable effect of aspartic acid salts on erythropoietic recovery and on regeneration of thymus weight was found during the first two weeks after irradiation. (orig.) [de

  1. Fe(II) and Co (II) complexes of (4-(4-bromophenyl)-[2,2'-bipyridine]-6-carboxylic acid) synthesis, characterization and electrochromic studies

    International Nuclear Information System (INIS)

    Saba, A.; Maqsood, Z.T.; Wasim, A.A.; Basha, F.Z.

    2017-01-01

    In this study novel complexes of substituted bipyridine (4-(4-bromophenyl)-[2,2'-bipyridine]-6-carboxylic acid) with Fe/sup +2/ and Co/sup +2/ were synthesized and characterized by different physical, analytical and spectral techniques which includes /sup 1/ H-NMR, MALDI-MS, FTIR, UV-VIS Spectrophotometry, CHN analysis and conductometry. Mole ratio method revealed that both complexes satisfied ML2 stoichiometry. Other characterization studies showed that substituted bipyridine acted as a tridentate ligand, with two pyridine N and one carboxylic O atom as binding sites per ligand molecule. The complexes were found octahedral, neutral and possessed fairly high molar absorptivities in visible region. Electrochromic studies revealed that Fe (II) complex had relatively good electrochromic properties with a reversible color change from blue to pale yellow. Co (II) complex, however, did not show significant electrochromic properties in the visible region. (author)

  2. A facile and novel approach towards carboxylic acid functionalization of multiwalled carbon nanotubes and efficient water dispersion

    KAUST Repository

    Rehman, Ata Ur

    2013-10-01

    A convenient, cheap and mild covalent functionalization route for multiwalled carbon nanotubes (MWCNTs) have been developed for the first time. The MWCNTs were treated with wet chemical oxidants (NaNO2/HCl, HNO3/H2O2) in order to modify MWCNTs with carboxyl groups. Surface functionality groups and morphology of MWCNTs were analyzed by FTIR, TGA, SEM and TEM. The results consistently confirmed the formation of carboxyl functionalities on MWCNTs, while the structure of MWCNTs has remained relatively intact. Functionalized MWCNTs showed good dispersion in aqueous media than untreated MWCNTs. Results show that NaNO2/HCl treatment is best suited for the chemical functionalization, giving optimum surface carboxyl groups and minimum length shortening of MWCNTs. © 2013 Elsevier B.V.

  3. A facile and novel approach towards carboxylic acid functionalization of multiwalled carbon nanotubes and efficient water dispersion

    KAUST Repository

    Rehman, Ata Ur; Abbas, Syed Mustansar; Ammad, Hafiz Muhammad; Badshah, Amin; Ali, Zulfiqar; Anjum, Dalaver H.

    2013-01-01

    A convenient, cheap and mild covalent functionalization route for multiwalled carbon nanotubes (MWCNTs) have been developed for the first time. The MWCNTs were treated with wet chemical oxidants (NaNO2/HCl, HNO3/H2O2) in order to modify MWCNTs with carboxyl groups. Surface functionality groups and morphology of MWCNTs were analyzed by FTIR, TGA, SEM and TEM. The results consistently confirmed the formation of carboxyl functionalities on MWCNTs, while the structure of MWCNTs has remained relatively intact. Functionalized MWCNTs showed good dispersion in aqueous media than untreated MWCNTs. Results show that NaNO2/HCl treatment is best suited for the chemical functionalization, giving optimum surface carboxyl groups and minimum length shortening of MWCNTs. © 2013 Elsevier B.V.

  4. Body odour of monozygotic human twins: a common pattern of odorant carboxylic acids released by a bacterial aminoacylase from axilla secretions contributing to an inherited body odour type.

    Science.gov (United States)

    Kuhn, Fabian; Natsch, Andreas

    2009-04-06

    It is currently not fully established whether human individuals have a genetically determined, individual-specific body odour. Volatile carboxylic acids are a key class of known human body odorants. They are released from glutamine conjugates secreted in axillary skin by a specific Nalpha-acyl-glutamine-aminoacylase present in skin bacteria. Here, we report a quantitative investigation of these odorant acids in 12 pairs of monozygotic twins. Axilla secretions were sampled twice and treated with the Nalpha-acyl-glutamine-aminoacylase. The released acids were analysed as their methyl esters with comprehensive two-dimensional gas chromatography and time-of-flight mass spectrometry detection. The pattern of the analytes was compared with distance analysis. The distance was lowest between samples of the right and the left axilla taken on the same day from the same individual. It was clearly greater if the same subject was sampled on different days, but this intra-individual distance between samples was only slightly lower than the distance between samples taken from two monozygotic twins. A much greater distance was observed when comparing unrelated individuals. By applying cluster and principal component analyses, a clear clustering of samples taken from one pair of monozygotic twins was also confirmed. In conclusion, the specific pattern of precursors for volatile carboxylic acids is subject to a day-to-day variation, but there is a strong genetic contribution. Therefore, humans have a genetically determined body odour type that is at least partly composed of these odorant acids.

  5. Membrane fractionation of herring marinade for separation and recovery of fats, proteins, amino acids, salt, acetic acid and water

    DEFF Research Database (Denmark)

    Fjerbæk Søtoft, Lene; Lizarazu, Juncal Martin; Razi Parjikolaei, Behnaz

    2015-01-01

    In the production of marinated herring, nearly one ton of acidic saline marinade is produced per 1.5 tons herring fillet. This spent marinade contains highly valuable compounds such as proteins and amino acids. Membranes are suited to recover these substances. In this work, six membrane stages...... containing sugars, amino acids and smaller peptides and a NF permeate containing salt and acetic acid ready for reuse. 42% of the spent marinade is recovered to substitute fresh water and chemicals. The Waste water amount is reduced 62.5%. Proteins are concentrated 30 times, while amino acids and smaller...

  6. Bile salt tolerance of Lactococcus lactis is enhanced by expression of bile salt hydrolase thereby producing less bile acid in the cells.

    Science.gov (United States)

    Bi, Jie; Liu, Song; Du, Guocheng; Chen, Jian

    2016-04-01

    Changes of bile salt tolerance, morphology and amount of bile acid within cells were studied to evaluate the exact effects of bile salt hydrolase (BSH) on bile salt tolerance of microorganism. The effect of BSHs on the bile salt tolerance of Lactococcus lactis was examined by expressing two BSHs (BSH1 and BSH2). Growth of L. lactis expressing BSH1 or BSH2 was better under bile salt stress compared to wild-type L. lactis. As indicated by transmission electron microscopy, bile acids released by the action of BSH induced the formation of micelles around the membrane surface of cells subject to conjugated bile salt stress. A similar micelle containing bile acid was observed in the cytoplasm by liquid chromatography-mass spectrometry. BSH1 produced fewer bile acid micelles in the cytoplasm and achieved better cell growth of L. lactis compared to BSH2. Expression of BSH improved bile salt tolerance of L. lactis but excessive production by BSH of bile acid micelles in the cytoplasm inhibited cell growth.

  7. 40 CFR 180.1121 - Boric acid and its salts, borax (sodium borate decahydrate), disodium octaborate tetrahydrate...

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Boric acid and its salts, borax... salts, borax (sodium borate decahydrate), disodium octaborate tetrahydrate, boric oxide (boric anhydride... its salts, borax (sodium borate decahydrate), disodium octaborate tetrahydrate, boric oxide (boric...

  8. Effect of salicylic acid on the growth photosynthesis and carbohydrate metabolism in salt stressed maize plants

    International Nuclear Information System (INIS)

    Moussa, H.R.; Khodary, S.E.A.

    2003-01-01

    Aqueous solutions of salicylic acid as a spray to Na CI-treated corn (Zea mays L,) significantly increased the growth of shoots and roots as measured after seven days of treatment. Spraying of salicylic acid caused significant increases in the activity of both ribulose 1,5 bisphosphate carboxylase (rubisco) enzyme and photosynthetic pigments. Moreover, salicylic acid treatment induced high values of soluble carbohydrate fractions in salt stressed plants as compared with salicylic acid treated samples. These data suggest that salicylic acid might improve the growth pattern of NaCl-treated maize plants via increasing the rate of photosynthesis and carbohydrate metabolism

  9. Polyfluoroalkyl phosphate esters and perfluoroalkyl carboxylic acids in target food samples and packaging--method development and screening.

    Science.gov (United States)

    Gebbink, Wouter A; Ullah, Shahid; Sandblom, Oskar; Berger, Urs

    2013-11-01

    Polyfluoroalkyl phosphate mono-, di-, and tri-esters (mono-, di-, and triPAPs) are used to water- and grease-proof food packaging materials, and these chemicals are known precursors to perfluoroalkyl carboxylic acids (PFCAs). Existing analytical methods for PAPs lack sample clean-up steps in the sample preparation. In the present study, a method based on ultra performance liquid chromatography coupled to tandem mass spectrometry (UPLC/MS/MS) was developed and optimized for the analysis of mono-, di-, and triPAPs, including a clean-up step for the raw extracts. The method was applied to food samples and their PAP-containing packaging materials. The optimized UPLC/MS/MS method enabled the separation and identification of a total of 4 monoPAPs, 16 diPAPs, and 7 triPAPs in the technical mixture Zonyl®-RP. For sample clean-up, weak anion exchange solid phase extraction columns were tested. PAPs standard solutions spiked onto the columns were separated into a fraction containing neutral compounds (triPAPs) and a fraction with ionic compounds (mono- and diPAPs) with recoveries between 72-110%. Method limits of quantification for food samples were in the sub to low picogram per gram range. For quantitative analysis of PAPs, compound-specific labeled internal standards showed to be essential as sorption and matrix effects were observed. Mono-, di-, and/or triPAPs were detected in all food packaging materials obtained from the Swedish market. Up to nine diPAPs were detected in the food samples, with the 6:2/6:2 and 6:2/8:2 diPAPs as the dominant compounds. DiPAP concentrations in the food samples ranged from 0.9 to 36 pg/g, which was comparable to individual PFCA concentrations in the same samples. Consumption of food packed in PAP-containing materials could be an indirect source of human exposure to PFCAs.

  10. Impact of phenazine-1-carboxylic acid upon iron speciation and microbial biomass in the rhizosphere of wheat

    Science.gov (United States)

    LeTourneau, M.; Marshall, M.; Grant, M.; Freeze, P.; Cliff, J. B.; Lai, B.; Strawn, D. G.; Thomashow, L. S.; Weller, D. M.; Harsh, J. B.

    2015-12-01

    Phenazine-1-carboxylic acid (PCA) is a redox-active antibiotic produced by diverse bacterial taxa, and has been shown to facilitate interactions between biofilms and iron (hydr)oxides in culture systems (Wang et al. 2011, J Bacteriol 192: 365). Because rhizobacterial biofilms are a major sink for plant-derived carbon and source for soil organic matter (SOM), and Fe (hydr)oxides have reactive surfaces that influence the stability of microbial biomass and SOM, PCA-producing rhizobacteria could influence soil carbon fluxes. Large populations of Pseudomonas fluorescens strains producing PCA in concentrations up to 1 μg/g root have been observed in the rhizosphere of non-irrigated wheat fields covering 1.56 million hectares of central Washington state. This is one of the highest concentrations ever reported for a natural antibiotic in a terrestrial ecosystem (Mavrodi et al. 2012, Appl Environ Microb 78: 804). Microscopic comparisons of PCA-producing (PCA+) and non-PCA-producing (PCA-) rhizobacterial colony morphologies, and comparisons of Fe extractions from rhizosphere soil inoculated with PCA+ and PCA- strains suggest that PCA promotes biofilm development as well as dramatic Fe transformations throughout the rhizosphere (unpublished data). In order to illustrate PCA-mediated interactions between biofilms and Fe (hydr)oxides in the rhizosphere, identify the specific Fe phases favored by PCA, and establish the ramifications for stability and distribution of microbial biomass and SOM, we have collected electron micrographs, X-ray fluorescence images, X-ray absorption near-edge spectra, and secondary-ion mass spectrometry images of wheat root sections inoculated with 15N-labelled PCA+ or PCA- rhizobacteria. These images and spectra allow us to assess the accumulation, turnover, and distribution of microbial biomass, the associations between Fe and other nutrients such as phosphorus, and the redox status and speciation of iron in the presence and absence of PCA. This

  11. Physiological Mechanism of Salicylic Acid for Alleviation of Salt Stress in Rice

    Directory of Open Access Journals (Sweden)

    D. Jini

    2017-03-01

    Full Text Available Soil salinity is one of the most important problems of crop production in estuarine and coastal zones. Improvement in salt tolerance of major food crops is an important way for the economic utilization of coastal zones. This study proved that the application of salicylic acid (SA improved the growth and yield under salt stress conditions and investigated its physiological mechanisms for salt tolerance. The investigation on the effect of SA for salt tolerance during germination showed that the decreased rates of germination and growth (in terms of shoot and root lengths by the salt stress were significantly increased by the SA application (SA + NaCl. The treatment of SA to the high and low saline soils enhanced the growth, yield and nutrient values of rice. The effects of SA on Na+, K+ and Cl– ionic accumulation were traced under salt stress condition by inductively coupled plasma optical emission spectrometry and ion chromatography. It was revealed that the increased accumulation of Na+ and Clˉ ions by the salt stress were reduced by SA application. An increased concentration of endogenous SA level was detected from the SA-treated rice varieties (ASD16 and BR26 by liquid chromatography electrospray Ionization-tandem mass spectrometry. The activities of antioxidant enzymes such as superoxide dismutase, catalase and peroxidase were increased by salt stress whereas decreased by the SA application. The study proved that the application of SA could alleviate the adverse effects of salt stress by the regulation of physiological mechanism in rice plants. In spite of salt stress, it can be applied to the coastal and estuarine regions to increase the rice production.

  12. CO2 Capture from Flue gas using Amino acid salt solutions

    DEFF Research Database (Denmark)

    Lerche, Benedicte Mai

    to storage. Typical solvents for the process are based on aqueous solutions of alkanolamines, such as mono-ethanolamine (MEA), but their use implies economic disadvantages and environmental complications. Amino acid salt solutions have emerged as an alternative to the alkanolamines, partlybecause...... for measuring of CO2 solubility based on the semi-flow method. A validation study of CO2 solubility in aqueous solutions of MEA is presented. Chapter 5 focuses on the determination of the chemical compositions of the precipitations, which arise in the five amino acid salt solutions upon CO2 absorption...

  13. Survival of Four Probiotic Strains in Acid, Bile Salt and After Spray Drying

    OpenAIRE

    Rawichar Chaipojjana; Suttipong Phosuksirikul; Arunsri Leejeerajumnean

    2014-01-01

    The objective of the study was to select the survival of probiotic strains when exposed to acidic and bile salts condition. Four probiotic strains Lactobacillus casei subsp. rhamnosus TISTR 047, Lactobacillus casei TISTR 1500, Lactobacillus acidophilus TISTR 1338 and Lactobacillus plantarum TISTR 1465 were cultured in MRS broth and incubated at 35ºC for 15 hours before being inoculated into acidic condition 5 M HCl, pH 2 for 2 hours and bile salt 0.3%, pH 5.8 for 8 hour. ...

  14. Highly selective and efficient imprinted polymers based on carboxyl-functionalized magnetic nanoparticles for the extraction of gallic acid from pomegranate rind.

    Science.gov (United States)

    Zhang, Junjie; Li, Benqiang; Yue, Huijuan; Wang, Jing; Zheng, Yuansuo

    2018-01-01

    With the combined surface imprinting technique and immobilized template strategy, molecularly imprinted magnetic nanoparticles were successfully prepared and coupled with high-performance liquid chromatography to selectively separate and determine gallic acid from the pomegranate rind. On the surface of carboxyl-functionalized magnetic nanospheres, thin imprinting shells were formed using dopamine as monomer and crosslinker. The characteristics, polymerization conditions, and adsorption performances of the resultant nanomaterials were investigated in detail. In addition of good crystallinity, satisfactory magnetism, and uniform morphology of the obtained polymers, they had rapid binding kinetics, high adsorption capacity, and favorable reusability. In the mixed solution of four hydroxybenzoic acids, the prepared nanomaterials have an excellent selectivity to gallic acid with an imprinting factor of as high as 17.5. Therefore, the polymers have great potentials in specific extraction and enrichment of gallic acid from the complex natural resources. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Development of starch biofilms using different carboxylic acids as plasticizers; Desenvolvimento de biofilmes de amido utilizando como plastificantes diferentes acidos carboxilicos

    Energy Technology Data Exchange (ETDEWEB)

    Cruz, L.C.; Miranda, C.S.; Santos, W.J. dos; Goncalves, A.P.B.; Oliveira, J.C.; Jose, N.M., E-mail: uanaconceicaocruz@gmail.com [Universidade Federal da Bahia (GECIM/UFBA), Salvador, BA (Brazil). Programa de Pos-Graduacao em Engenharia Quimica. Grupo de Energia e Ciencias dos Materiais

    2014-07-01

    Biodegradable films have become a widely exploited issue among scientists because of their positive environmental impact, besides their potential to promote better food conservation and an increase in shelf life. Starch has been studied in this field due to its availability, low cost and biodegradability. However, starch films tend to be brittle and they need addition of a plasticizer to enable their usage. In this work, starch films were synthesized with different carboxylic acids as plasticizers, aiming to observe the effect of the acids chain size in the final films properties. The acids used were: oxalic, succinic and adipic. The materials were produced by casting and characterized by DSC, TG, DRX e FTIR. It was observed that the acids chain size influenced on the thermal and structural properties of the films. (author)

  16. Crystal structure of 7,7-dimethyl-6-methylidenetricyclo[6.2.1.01,5]undecane-2-carboxylic acid

    Directory of Open Access Journals (Sweden)

    Noureddine Beghidja

    2015-02-01

    Full Text Available In the title compound, C15H22O2, both five-membered rings display an envelope conformation whereas the six-membered ring displays a chair conformation. In the crystal, pairs of O—H...O hydrogen bonds between carboxylic groups link molecules, related by a twofold rotation axis, into supramolecular dimers.

  17. Solubility of fumaric acid and its monosodium salt

    NARCIS (Netherlands)

    Roa Engel, C.A.; Horst, J.H. ter; Pieterse, M.; Wielen, L.A.M. van der; Straathof, A.J.J.

    2013-01-01

    Fumaric acid is a dicarboxylic acid applied in food industry and in some polymers. Currently, its fermentative production from renewable resources is receiving much attention, and crystallization is used to recover it. To determine the window of operation for crystallization from multicomponent

  18. Sulfur-containing constituents and one 1H-pyrrole-2-carboxylic acid derivative from pineapple [Ananas comosus (L.) Merr.] fruit.

    Science.gov (United States)

    Zheng, Zong-Ping; Ma, Jinyu; Cheng, Ka-Wing; Chao, Jianfei; Zhu, Qin; Chang, Raymond Chuen-Chung; Zhao, Ming; Lin, Zhi-Xiu; Wang, Mingfu

    2010-12-01

    Two sulfur-containing compounds, (S)-2-amino-5-((R)-1-carboxy-2-((E)-3-(4-hydroxy-3-methoxyphenyl)allylthio)ethyl-amino)-5-oxopentanoic acid (1) and (S)-2-amino-5-((R)-1-(carboxymethylamino)-3-((E)-3-(4-hydroxyphenyl)allylthio)-1-oxopropan-2-ylamino)-5-oxopentanoic acid (2), and one 1H-pyrrole-2-carboxylic acid derivative, 6-(3-(1H-pyrrole-2-carbonyloxy)-2-hydroxypropoxy)-3,4,5-trihydroxy-tetrahydro-2H-pyran-2-carboxylic acid (3), together with eighteen known phenolic compounds, were isolated from the fruits of pineapple. Their structures were elucidated by a combination of spectroscopic analyses. Some of these compounds showed inhibitory activities against tyrosinase. The half maximal inhibitory concentration values of compounds 1, 4, 5, 6, 7 are lower than 1 mM. These compounds may contribute to the well-known anti-browning effect of pineapple juice and be potential skin whitening agents in cosmetic applications. Copyright © 2010 Elsevier Ltd. All rights reserved.

  19. In situ SERS and X-ray photoelectron spectroscopy studies on the pH-dependant adsorption of anthraquinone-2-carboxylic acid on silver electrode

    Science.gov (United States)

    Li, Dan; Jia, Shaojie; Fodjo, Essy Kouadio; Xu, Hu; Wang, Yuhong; Deng, Wei

    2016-03-01

    In this study, in situ surface-enhanced Raman scattering (SERS) spectroelectrochemistry and angle-resolved X-ray photoelectron spectroscopy (AR-XPS) are used to investigate the redox reaction and adsorption behavior of anthraquinone-2-carboxylic acid (AQ-2-COOH) on an Ag electrode at different pH values. The obtained results indicate that AQ-2-COOH is adsorbed tilted on the Ag electrode through O-atom of ring carbonyl in a potential range from -0.3 to -0.5 V vs. SCE, but the orientation turns to more tilted orientation with both O-atom of the ring carbonyl and carboxylate group in positive potential region for pH 6.0 and 7.4. However, at pH 10.0, the orientation adopts tilted conformation constantly on the Ag electrode with both O-atom of the anthraquinone ring and carboxylate group in the potential range from -0.3 to -0.5 V vs. SCE or at positive potentials. Moreover, the adsorption behavior of AQ-2-COOH has been further confirmed by AR-XPS on the Ag surface. Proposed reasons for the observed changes in orientation are presented.

  20. Thermophysical property characterization of aqueous amino acid salt solution containing serine

    International Nuclear Information System (INIS)

    Navarro, Shanille S.; Leron, Rhoda B.; Soriano, Allan N.; Li, Meng-Hui

    2014-01-01

    Highlights: • Thermophysical properties of aqueous potassium and sodium salt solutions of serine were studied. • Density, viscosity, refractive index and electrolytic conductivity of the solution were measured. • The concentrations of amino acid salt ranges from x 1 = 0.009 to 0.07. • The temperature range studied was (298.15 to 343.15) K. • The measured data were represented satisfactorily by using the applied correlations. - Abstract: Thermophysical property characterization of aqueous potassium and sodium salt solutions containing serine was conducted in this study; specifically the system’s density, refractive index, electrical conductivity, and viscosity. Measurements were obtained over a temperature range of (298.15 to 343.15) K and at normal atmospheric pressure. Composition range from x 1 = 0.009 to 0.07 for aqueous potassium and sodium salt solutions containing serine was used. The sensitivity of the system’s thermophysical properties on temperature and composition variation were discussed and correlated based on the equations proposed for room temperature ionic liquids. The density, viscosity, and refractive index measurements of the aqueous systems were found to decrease as the temperature increases at fixed concentration and the values increase as the salt concentration increases (water composition decreases) at fixed temperature. Whereas, a different trend was observed for the electrical conductivity data; at fixed concentration, the conductivity values increase as the temperature increases and at fixed temperature, its value generally increases as the salt concentration increases but only to a certain level (specific concentration) wherein the conductivity of the solution starts to decrease when the concentration of the salt is further increased. Calculation results show that the applied models were satisfactory in representing the measured properties in the aqueous amino acid salt solution containing serine

  1. Long-chain perfluoroalkyl carboxylic acids in Pacific cods from coastal areas in northern Japan: A major source of human dietary exposure

    International Nuclear Information System (INIS)

    Fujii, Yukiko; Sakurada, Tsukasa; Harada, Kouji H.; Koizumi, Akio; Kimura, Osamu; Endo, Tetsuya; Haraguchi, Koichi

    2015-01-01

    This study investigates perfluoroalkyl carboxylic acids (PFCAs) contamination of edible fish muscle from Japanese coastal waters. The concentrations of PFCAs with 8–14 carbon atoms (C8–C14) in Pacific cods in Hokkaido, Japan were 51 (median: pg/g-wet weight) for C8, 93 for C9, 99 for C10, 746 for C11, 416 for C12, 404 for C13, and 93 for C14. The levels of C9–C14 PFCAs in fish were strongly correlated to each other, but not to C8 and the other chlorinated persistent organic pollutants, indicating that C9–C14 PFCAs have a different emission source and/or bioaccumulation mechanism. The relative ratios between estimated PFCAs intake through fish consumption and the reported total dietary exposure of PFCAs were less than 1 for C8 to C9, but were more than 1 for C10 to C14. This result strongly suggests that fish consumption is a significant source of human dietary exposure to C10–C14 PFCAs. - Highlights: • Perfluoroalkyl carboxylic acids were detected in edible cod fish from Japanese coastal waters. • The levels of long-chain PFCAs in fish were independent from those of C8 and other POPs. • Long chain PFCAs intake through fish and the reported total dietary exposure were comparable. • Sea fish such as Pacific cod may be a significant human dietary source of long-chain PFCAs. - Sea fish are a significant source of long-chain perfluoroalkyl carboxylic acids for the Japanese population

  2. Molecular interactions between selected sodium salts of bile acids and morphine hydrochloride.

    Science.gov (United States)

    Poša, Mihalj; Csanádi, János; Kövér, Katalin E; Guzsvány, Valéria; Batta, Gyula

    2012-06-01

    The objective of this study was to understand the prolonged analgesic action of morphine hydrochloride observed in the presence of sodium 12-oxochenodeoxycholanate. Based on literature, this phenomenon may be due to the formation of aggregates in the cell between the molecules of bile acids and morphine. In addition to the sodium 12-oxochenodeoxycholanate, the present investigation also included salts of cholic and 7-oxodeoxycholic acids. Saturation transfer difference NMR experiments showed that morphine binds to the bile acid molecule close to the aromatic protons H1 and H2 provided that the concentration of the bile acid salt approaches the critical micellar concentration (CMC). The spin-lattice relaxation times (T(1)) of the affected protons decrease significantly in the presence of micellar solutions of the bile acid salts, and the most pronounced change in T(1) was observed for sodium 7-oxodeoxycholate. Diffusion-ordered NMR experiments suggested that morphine hydrochloride can interact only with sodium 7-oxochenodeoxycholate. It can be supposed that the molecular ratio of sodium 7-oxodeoxycholate and morphine hydrochloride in the mixed micelle is 2:1. The CMC values of mixed micelles do not differ from the CMC values of the micelle constituents, which suggests that the binding of morphine hydrochloride does not perturb the hydrophobic domain of the bile acid molecule. In the presence of bile acids, the transfer rate constant (k(12)) of morphine hydrochloride from the buffered aqueous solution to chloroform (model of the cell membrane) shows a decrease. A significant decrease of the k(12) was also observed in the presence of micellar solutions. Kinetic measurements indicated that, in addition to micellar interaction between morphine hydrochloride and sodium salts of bile acids, a complex may also be formed in chloroform via hydrogen bonds formed between the drug and bile acid molecules. Copyright © 2012 Elsevier B.V. All rights reserved.

  3. Heat capacity and thermodynamics of solid and liquid pyridine-3-carboxylic acid (nicotinic acid) over the temperature range 296 K to 531 K

    International Nuclear Information System (INIS)

    Joseph, Abhinav; Bernardes, Carlos E.S.; Minas da Piedade, Manuel E.

    2012-01-01

    Highlights: ► We determined the heat capacity of solid and liquid nicotinic acid by DSC. ► We determined Δ 357.8K 305.6K H m o (NA,crII) by Calvet microcalorimetry. ► We studied the thermodynamics of the cr II → cr I phase transition. ► We determined the Δ f G m o –T diagram of nicotinic acid for T = (296 to 531) K. - Abstract: The molar heat capacity of pyridine-3-carboxylic acid (nicotinic acid) for T = (296 to 531) K was investigated by differential scanning calorimetry (DSC) and Calvet-drop microcalorimetry. The measurements extended up to the liquid range and also covered the interval where a reversible and fast solid-solid (cr II → cr I) phase transition occurs. The molar enthalpies and entropies of that phase transition and of fusion were obtained as T trs = (455.0 ± 0.2) K, Δ trs H m o = (0.90 ± 0.10) kJ ⋅ mol −1 , Δ trs S m o = (1.98 ± 0.22) J ⋅ K −1 ⋅ mol −1 , T fus = (509.91 ± 0.04) K, Δ fus H m o = (28.2 ± 0.1) kJ ⋅ mol −1 , and Δ fus S m o = (55.30 ± 0.16) J ⋅ K −1 ⋅ mol −1 . By combining these experimental results with the previously reported Δ sub H m (NA,cr II) at T = 366.5 K, the corresponding entropy in the gaseous state calculated at the B3LYP/6-31+G(d,p) level of theory, and Δ f H m o (NA),cr II) at T = 298.15 K, it was possible to estimate the standard molar Gibbs energy of formation functions necessary for the construction of the Δ f G m ∘ vs. T diagram illustrating the enantiotropic nature of this system.

  4. Catalytic activity of supported silver and potassium salts of tungstophosphoric acid in dehydration of ethanol

    International Nuclear Information System (INIS)

    Haber, J.; Matachowski, L.; Pamin, K.; Napruszewska, B.

    2002-01-01

    Potassium and silver salts of tungstophosphoric acid (HPW) have been supported on silica. Two series of potassium and silver salts of tungstophosphoric acid K x H 3-x PW 12 O 40 and Ag x H 3-x PW 12 O 40 where x = 1;2;3 supported on silica were prepared using incipient wetness method. In a typical synthesis, the heteropolyacid which after deposition on silica was washed with water to remove the part of heteropolyacid not bound to the support was reacted with silver or potassium salt. The vapor-phase dehydration of ethanol was employed as a test reaction. All the catalytic tests were carried out in a conventional flow type reactor, under atmospheric pressure, in the temperature range 125-500 o C. The results of these studies were used to explain the differences between the catalytic activities of heteropolysalts of potassium and silver supported on silica. (author)

  5. Investigations and design of pyridine-2-carboxylic acid thiazol-2-ylamide analogs as methionine aminopeptidase inhibitors using 3D-QSAR and molecular docking

    DEFF Research Database (Denmark)

    Hauser, Alexander Sebastian

    2014-01-01

    complexes, four new pyridine-2-carboxylic acid thiazol-2-ylamide analogs were designed. These analogs exhibit significantly better predicted activity than the reported molecules. The present work has implications for the development of novel antibiotics as potent MetAP inhibitors.......Methionine amino peptidases (MetAPs) are metalloproteases that remove co-translational N-terminal methionine from nascent polypeptide chains. Due to their essential role in protein synthesis, MetAPs are considered as potential targets for antibacterial drugs. In the present work, three...

  6. Luminescent hybrid lanthanide sulfates and lanthanide sulfonate-carboxylates with 1,10-phenanthroline involving in-situ oxidation of 2-mercaptonbenzoic acid

    Science.gov (United States)

    Zhong, Jie-Cen; Wan, Fang; Sun, Yan-Qiong; Chen, Yi-Ping

    2015-01-01

    A series of lanthanide sulfates and lanthanide sulfonate-carboxylates, [Ln2(phen)2(SO4)3(H2O)2]n (I:Ln=Nd(1a), Sm(1b), Eu(1c), phen=1,10-phenanthroline) and [Ln(phen)(2-SBA)(BZA)]n (II: Ln=Sm(2a), Eu(2b), Dy(2c), 2-SBA=2-sulfobenzoate, BZA=benzoate) have been hydrothermally synthesized from lanthanide oxide, 2-mercaptonbenzoic acid with phen as auxiliary ligand and characterized by single-crystal X-ray diffraction, elemental analyses, IR spectra, TG analyses and luminescence spectroscopy. Interestingly, SO4 2 - anions in I came from the in situ deep oxidation of thiol groups of 2-mercaptonbenzoic acid while 2-sulfobenzoate and benzoate ligands in II from the middle oxidation and desulfuration reactions of 2-mercaptonbenzoic acid. Compounds I are organic-inorganic hybrid lanthanide sulfates, which have rare one-dimensional column-like structures. Complexes II are binuclear lanthanide sulfonate-carboxylates with 2-sulfobenzoate and benzoate as bridges and 1,10-phenanthroline as terminal. Photoluminescence studies reveal that complexes I and II exhibit strong lanthanide characteristic emission bands in the solid state at room temperature.

  7. 78 FR 54625 - Citric Acid and Certain Citrate Salts From the People's Republic of China: Notice of Partial...

    Science.gov (United States)

    2013-09-05

    ... DEPARTMENT OF COMMERCE International Trade Administration [C-570-938] Citric Acid and Certain Citrate Salts From the People's Republic of China: Notice of Partial Rescission of Countervailing Duty... of the countervailing duty (CVD) order on citric acid and certain citrate salts from the People's...

  8. 76 FR 2648 - Citric Acid and Certain Citrate Salts From People's Republic of China: Extension of Time Limit...

    Science.gov (United States)

    2011-01-14

    ... DEPARTMENT OF COMMERCE International Trade Administration [C-570-938] Citric Acid and Certain Citrate Salts From People's Republic of China: Extension of Time Limit for the Preliminary Results of the... duty order on citric acid and certain citrate salts from the People's Republic of China, covering the...

  9. Synergy of boric acid and added salts in the catalytic dehydration of hexoses to 5-hydroxymethylfurfural in water

    DEFF Research Database (Denmark)

    Hansen, Thomas Steen; Mielby, Jerrik Jørgen; Riisager, Anders

    2011-01-01

    Boric acid and salts showed a synergistic effect on the dehydration of concentrated aqueous sugar solutions to yield 5-hydroxymethylfurfural.......Boric acid and salts showed a synergistic effect on the dehydration of concentrated aqueous sugar solutions to yield 5-hydroxymethylfurfural....

  10. Conductivities of poly(ethylene oxide)-alkali salts with aromatic and heterocyclic anions

    Energy Technology Data Exchange (ETDEWEB)

    Voss, J P [Dept. of Engineering Materials, Univ. of Sheffield (United Kingdom); Batty, S V [Dept. of Engineering Materials, Univ. of Sheffield (United Kingdom); Patel, J P [Dept. of Engineering Materials, Univ. of Sheffield (United Kingdom); Wright, P V [Dept. of Engineering Materials, Univ. of Sheffield (United Kingdom)

    1993-03-01

    Complexes of PEO with the sodium salts of imidazole, benzimidazole, 2-methylbenzimidazole, 4-phenylphenol and a mesogenic ester of benzimidazole-5-carboxylic acid have been prepared. The latter forms a mixed organised phase with its uncharged analogue. Highest conductivities (ca. 5x10[sup -4] cm[sup -1] at 100 C) are observed with the sodium salt of benzimidazole; the corresponding complex with the lithium salt has a lower conductivity (5x10[sup -5] S cm[sup -1]). (orig.)

  11. Influence of salicylic acid on in vitro propagation and salt tolerance ...

    African Journals Online (AJOL)

    Salicylic acid (SA) has been reported to improve in vitro regeneration as well as induce abiotic stress tolerance in plants. The effects of varying SA concentrations (0, 0.5, and 1 mM) on in vitro shoot apices of two Hibiscus species, Hibiscus moscheutos (cv 'Luna Red') and Hibiscus acetosella, grown under various salt ...

  12. 77 FR 24461 - Citric Acid and Certain Citrate Salts From Canada: Final Results of Antidumping Duty...

    Science.gov (United States)

    2012-04-24

    ... that satisfies the standards set forth in the United States Pharmacopeia and has been mixed with a... meaning of 19 CFR 351.106(c)(1), in which case the cash deposit rate will be zero; (2) for previously.... See Citric Acid and Certain Citrate Salts from Canada and the People's Republic of China: Antidumping...

  13. Disproportionation of the calcium salt of atorvastatin in the presence of acidic excipients

    DEFF Research Database (Denmark)

    Christensen, Niels Peter Aae; Rantanen, Jukka; Cornett, Claus

    2012-01-01

    The aim of the present study was to combine vibrational spectroscopy and chemometrics for investigating excipient-induced disproportionation of the calcium salt of atorvastatin into the corresponding free acid form in environments relevant to manufacturing and storage of solid dosage formulations...

  14. Effects of mixed volatile fatty acid sodium salt on insulin-like growth ...

    African Journals Online (AJOL)

    Effects of mixed volatile fatty acid sodium salt on insulin-like growth factor-I (IGF-I) and insulin-like growth factor-binding protein-3 (IGFBP-3) in plasma and rumen tissue, and rumen epithelium development in lambs.

  15. Use of triammonium salt of aurin tricarboxylic acid as risk mitigant for aluminum hydride

    Science.gov (United States)

    Cortes-Concepcion, Jose A.; Anton, Donald L.

    2017-08-08

    A process and a resulting product by process of an aluminum hydride which is modified with by physically combining in a ball milling process an aluminum hydride with a triammonium salt of aurin tricarboxylic acid. The resulting product is an aluminum hydride which is resistant to air, ambient moisture, and liquid water while maintaining useful hydrogen storage and release kinetics.

  16. 40 CFR 721.3031 - Boric acid (H3BO3), zinc salt (2=3).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Boric acid (H3BO3), zinc salt (2=3). 721.3031 Section 721.3031 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.3031 Boric acid (H3BO...

  17. Effects of Food on the Pharmacokinetics of Omega-3-Carboxylic Acids in Healthy Japanese Male Subjects: A Phase I, Randomized, Open-label, Three-period, Crossover Trial.

    Science.gov (United States)

    Shimada, Hitoshi; Nilsson, Catarina; Noda, Yoshinori; Kim, Hyosung; Lundström, Torbjörn; Yajima, Toshitaka

    2017-09-01

    Omega-3-carboxylic acids (OM3-CA) contain omega-3 free fatty acids, such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), as carboxylic acids. Food intake is known to affect the bioavailability of ethyl ester fatty acid formulations. We conducted a phase I study to investigate the effects of the timing of OM3-CA administration relative to food intake on the pharmacokinetics of EPA and DHA. In this randomized, open-label, three-period crossover study, Japanese healthy male subjects were administered 4×1 g OM3-CA capsules with continued fasting, before a meal, or after a meal. All subjects fasted for ≥10 h prior to drug/meal administration. The primary objective was to examine the effect of meal timing on the pharmacokinetics of EPA and DHA after OM3-CA administration. The secondary objectives were to examine the safety and tolerability of OM3-CA. A total of 42 Japanese subjects was enrolled in the study. The baseline-adjusted maximum concentration and area under the concentration-time curve from 0 to 72 h for EPA, DHA, and EPA +DHA were lower in the fasting and before meal conditions than in the after meal condition. The maximum total EPA, total DHA, and total EPA+DHA concentrations were reached later when administered in fasting conditions than in fed conditions, indicating slower absorption in fasting conditions. Diarrhea was reported by five, six, and no subjects in the fasting, before meal, and after meal conditions, respectively. The timing of OM3-CA administration relative to food intake influences the systemic bioavailability of EPA and DHA in healthy Japanese male subjects. NCT02372344.

  18. Salicylic acid promotes plant growth and salt-related gene expression in Dianthus superbus L. (Caryophyllaceae) grown under different salt stress conditions.

    Science.gov (United States)

    Zheng, Jian; Ma, Xiaohua; Zhang, Xule; Hu, Qingdi; Qian, Renjuan

    2018-03-01

    Salt stress is a critical factor that affects the growth and development of plants. Salicylic acid (SA) is an important signal molecule that mitigates the negative effects of salt stress on plants. To elucidate salt tolerance in large pink Dianthus superbus L. (Caryophyllaceae) and the regulatory mechanism of exogenous SA on D. superbus under different salt stresses, we conducted a pot experiment to evaluate leaf biomass, leaf anatomy, soluble protein and sugar content, and the relative expression of salt-induced genes in D. superbus under 0.3, 0.6, and 0.9% NaCl conditions with and without 0.5 mM SA. The result showed that exposure of D. superbus to salt stress lead to a decrease in leaf growth, soluble protein and sugar content, and mesophyll thickness, together with an increase in the expression of MYB and P5CS genes. Foliar application of SA effectively increased leaf biomass, soluble protein and sugar content, and upregulated the expression of MYB and P5CS in the D. superbus , which facilitated in the acclimation of D. superbus to moderate salt stress. However, when the plants were grown under severe salt stress (0.9% NaCl), no significant difference in plant physiological responses and relevant gene expression between plants with and without SA was observed. The findings of this study suggest that exogenous SA can effectively counteract the adverse effects of moderate salt stress on D. superbus growth and development.

  19. Optimization of Fluorescent Silicon Nano material Production Using Peroxide/ Acid/ Salt Technique

    International Nuclear Information System (INIS)

    Abuhassan, L.H.

    2009-01-01

    Silicon nano material was prepared using the peroxide/ acid/ salt technique in which an aqueous silicon-based salt solution was added to H 2 O 2 / HF etchants. In order to optimize the experimental conditions for silicon nano material production, the amount of nano material produced was studied as a function of the volume of the silicon salt solution used in the synthesis. A set of samples was prepared using: 0, 5, 10, 15, and 20 ml of an aqueous 1 mg/ L metasilicate solution. The area under the corresponding peaks in the infrared (ir) absorption spectra was used as a qualitative indicator to the amount of the nano material present. The results indicated that using 10 ml of the metasilicate solution produced the highest amount of nano material. Furthermore, the results demonstrated that the peroxide/ acid/ salt technique results in the enhancement of the production yield of silicon nano material at a reduced power demand and with a higher material to void ratio. A model in which the silicon salt forms a secondary source of silicon nano material is proposed. The auxiliary nano material is deposited into the porous network causing an increase in the amount of nano material produced and a reduction in the voids present. Thus a reduction in the resistance of the porous layer, and consequently reduction in the power required, are expected. (author)

  20. Regulation of ion homeostasis by aminolevulinic acid in salt-stressed wheat seedlings

    Energy Technology Data Exchange (ETDEWEB)

    Türk, Hülya, E-mail: hulyaa.turk@hotmail.com [Biology Department, Science Faculty, Ataturk University, Erzurum (Turkey); East Anatolian High Technology Research and Application Center, Ataturk University, Erzurum (Turkey); Genişel, Mucip, E-mail: m.genisel@hotmail.com [Department of Crop and Animal Production, Vocational High School, Agri (Turkey); Erdal, Serkan, E-mail: serkanerdal25@hotmail.com [Biology Department, Science Faculty, Ataturk University, Erzurum (Turkey)

    2016-04-18

    Salinity is regarded as a worldwide agricultural threat, as it seriously limits plant development and productivity. Salt stress reduces water uptake in plants by disrupting the osmotic balance of soil solution. In addition, it creates a damaged metabolic process by causing ion imbalance in cells. In this study, we aim to examine the negative effects of 5-aminolevulinic acid (ALA) (20 mg/l) on the ion balance in wheat seedling leaves exposed to salt stress (150 mM). Sodium is known to be highly toxic for plant cells at high concentrations, and is significantly increased by salt stress. However, it can be reduced by combined application of ALA and salt, compared to salt application alone. On the other hand, while the K{sup +}/Na{sup +} ratio was reduced by salt stress, ALA application changed this ratio in favor of K{sup +}. Manganese, iron, and copper were also able to reduce stress. However, ALA pre-treatment resulted in mineral level increments. Conversely, the stress-induced rise in magnesium, potassium, calcium, phosphorus, zinc, and molybdenum were further improved by ALA application. These data clearly show that ALA has an important regulatory effect of ion balance in wheat leaves.

  1. Efficacious Intestinal Permeation Enhancement Induced by the Sodium Salt of 10-undecylenic Acid, A Medium Chain Fatty Acid Derivative

    OpenAIRE

    Brayden, David J.; Walsh, Edwin

    2014-01-01

    10-undecylenic acid (UA) is an OTC antifungal therapy and a nutritional supplement. It is an unsaturated medium chain fatty acid (MCFA) derivative, so our hypothesis was that its 11-mer sodium salt, uC11, would improve intestinal permeation similar to the established enhancer, sodium caprate (C10), but without the toxicity of the parent saturated MCFA, decylenic acid (C11). MTT assay and high-content screening (HCS) confirmed a cytotoxicity ranking in Caco-2 cells: C11 > C10 = uC11. Five to t...

  2. Mechanism of in situ surface polymerization of gallic acid in an environmental-inspired preparation of carboxylated core-shell magnetite nanoparticles.

    Science.gov (United States)

    Tóth, Ildikó Y; Szekeres, Márta; Turcu, Rodica; Sáringer, Szilárd; Illés, Erzsébet; Nesztor, Dániel; Tombácz, Etelka

    2014-12-30

    Magnetite nanoparticles (MNPs) with biocompatible coatings are good candidates for MRI (magnetic resonance imaging) contrasting, magnetic hyperthermia treatments, and drug delivery systems. The spontaneous surface induced polymerization of dissolved organic matter on environmental mineral particles inspired us to prepare carboxylated core-shell MNPs by using a ubiquitous polyphenolic precursor. Through the adsorption and in situ surface polymerization of gallic acid (GA), a polygallate (PGA) coating is formed on the nanoparticles (PGA@MNP) with possible antioxidant capacity. The present work explores the mechanism of polymerization with the help of potentiometric acid-base titration, dynamic light scattering (for particle size and zeta potential determination), UV-vis (UV-visible light spectroscopy), FTIR-ATR (Fourier-transformed infrared spectroscopy by attenuated total reflection), and XPS (X-ray photoelectron spectroscopy) techniques. We observed the formation of ester and ether linkages between gallate monomers both in solution and in the adsorbed state. Higher polymers were formed in the course of several weeks both on the surface of nanoparticles and in the dispersion medium. The ratio of the absorbances of PGA supernatants at 400 and 600 nm (i.e., the E4/E6 ratio commonly used to characterize the degree of polymerization of humic materials) was determined to be 4.3, similar to that of humic acids. Combined XPS, dynamic light scattering, and FTIR-ATR results revealed that, prior to polymerization, the GA monomers became oxidized to poly(carboxylic acid)s due to ring opening while Fe(3+) ions reduced to Fe(2+). Our published results on the colloidal and chemical stability of PGA@MNPs are referenced thoroughly in the present work. Detailed studies on biocompatibility, antioxidant property, and biomedical applicability of the particles will be published.

  3. A broad diversity of volatile carboxylic acids, released by a bacterial aminoacylase from axilla secretions, as candidate molecules for the determination of human-body odor type.

    Science.gov (United States)

    Natsch, Andreas; Derrer, Samuel; Flachsmann, Felix; Schmid, Joachim

    2006-01-01

    Human body odor is to a large part determined by secretions of glands in the axillary regions. Two key odoriferous principles, 3-methylhex-2-enoic acid (3MH2; 4/5) and 3-hydroxy-3-methylhexanoic acid (HMHA; 6) have been shown to be released from glutamine conjugates secreted in the axilla by a specific N(alpha)-acyl-glutamine aminoacylase (N-AGA) obtained from axilla isolates of Corynebacteria sp. However, the low number of different odorants reported in humans stands in contrast to the observed high inter-individual variability in body odors. Axilla secretions of individual donors were, therefore, analyzed in detail. The secretions were treated with N-AGA, analyzed by GC/MS, and compared to undigested controls. Over 28 different carboxylic acids were released by this enzyme from odorless axilla secretions (Table 1). Many of these body odorants have not been reported before from a natural source, and they include several aliphatic 3-hydroxy acids with 4-Me branches, 3,4-unsaturated, 4-Et-branched aliphatic acids, and a variety of degradation products of amino acids. The odor threshold of some of the acids was found to be in the range of 1 ng. Most of these compounds were present in all donors tested, but in highly variable relative amounts, and they are, thus, candidate molecules as key components of a 'compound odor' determining the individual types of human body odor.

  4. Simultaneous determination of carbohydrates, carboxylic acids, alcohols, and metals in foods by high-performance liquid chromatography inductively coupled plasma atomic emission spectrometry.

    Science.gov (United States)

    Paredes, Eduardo; Maestre, Salvador E; Prats, Soledad; Todolí, José L

    2006-10-01

    The applicability of the HPLC-ICP-AES coupling for the simultaneous determination of carbohydrates, carboxylic acids, alcohols, and metals in a single chromatographic run has been demonstrated in the present work. Five saccharides, glucose, fructose, sucrose, sorbitol, and lactose; five carboxylic acids, citric, tartaric, malic, lactic, and acetic; and three alcohols, glycerol, ethanol, and methanol, have been determined. A H+ cation exchange column has been used to separate these compounds. The chromatograms have been obtained by monitoring the carbon emission signal at 193.09 nm. The results obtained by HPLC-ICP-AES have been compared against those found with conventional detection systems (i.e., refractive index, UV, and photodyode array detectors). The HPLC-ICP-AES method has shown the following features: (i) organic compounds and metals can be simultaneously determined; (ii) the detection method is universal; (iii) for nonvolatile organic compounds, a complete calibration line can be obtained from a single injection; and (iv) it provides absolute limits of detection similar to or lower than those found with conventional detection systems (i.e., on the order of several tens of nanograms of organic compound). The methodology has been validated through the analysis of food samples such as juices, isotonic beverages, wines, and a certified nonfat milk powder sample.

  5. RNA Interference of 1-Aminocyclopropane-1-carboxylic Acid Oxidase (ACO1 and ACO2 Genes Expression Prolongs the Shelf Life of Eksotika (Carica papaya L. Papaya Fruit

    Directory of Open Access Journals (Sweden)

    Rogayah Sekeli

    2014-06-01

    Full Text Available The purpose of this study was to evaluate the effectiveness of using RNA interference in down regulating the expression of 1-aminocyclopropane-1-carboxylic acid oxidase gene in Eksotika papaya. One-month old embryogenic calli were separately transformed with Agrobacterium strain LBA 4404 harbouring the three different RNAi pOpOff2 constructs bearing the 1-aminocyclopropane-1-carboxylic acid oxidase gene. A total of 176 putative transformed lines were produced from 15,000 calli transformed, selected, then regenerated on medium supplemented with kanamycin. Integration and expression of the targeted gene in putatively transformed lines were verified by PCR and real-time RT-PCR. Confined field evaluation of a total of 31 putative transgenic lines planted showed a knockdown expression of the targeted ACO1 and ACO2 genes in 13 lines, which required more than 8 days to achieve the full yellow colour (Index 6. Fruits harvested from lines pRNAiACO2 L2-9 and pRNAiACO1 L2 exhibited about 20 and 14 days extended post-harvest shelf life to reach Index 6, respectively. The total soluble solids contents of the fruits ranged from 11 to 14° Brix, a range similar to fruits from non-transformed, wild type seed-derived plants.

  6. Length scale dependence of the dynamic properties of hyaluronic acid solutions in the presence of salt.

    Science.gov (United States)

    Horkay, Ferenc; Falus, Peter; Hecht, Anne-Marie; Geissler, Erik

    2010-12-02

    In solutions of the charged semirigid biopolymer hyaluronic acid in salt-free conditions, the diffusion coefficient D(NSE) measured at high transfer momentum q by neutron spin echo is more than an order of magnitude smaller than that determined by dynamic light scattering, D(DLS). This behavior contrasts with neutral polymer solutions. With increasing salt content, D(DLS) approaches D(NSE), which is independent of ionic strength. Contrary to theoretical expectation, the ion-polymer coupling, which dominates the low q dynamics of polyelectrolyte solutions, already breaks down at distance scales greater than the Debye-Hückel length.

  7. Chiral gels derived from secondary ammonium salts of (1R,3S-(+-camphoric acid

    Directory of Open Access Journals (Sweden)

    Tapas Kumar Adalder

    2010-09-01

    Full Text Available In order to have access to chiral gels, a series of salts derived from (1R,3S-(+-camphoric acid and various secondary amines were prepared based on supramolecular synthon rationale. Out of seven salts prepared, two showed moderate gelation abilities. The gels were characterized by differential scanning calorimetry, table top rheology, scanning electron microscopy, single crystal and powder X-ray diffraction. Structure property correlation based on X-ray diffraction techniques remain inconclusive indicating that some of the integrated part associated with the gelation phenomena requires a better understanding.

  8. Synthesis and research of the physical-chemical properties of 5-((2-bromphenyl-4-amino-4H-1,2,4-triazole-3-ylthioacetic acid salts

    Directory of Open Access Journals (Sweden)

    Ye. S. Pruglo

    2018-03-01

    Full Text Available At this stage of the development of modern science the scientists get a lot of questions in the field of medicine and pharmacy, and one of the most important among them is the study and search of new ways of synthesis of high-performance and low-toxic substances. Special attention is paid to 1,2,4-triazole and xanthine. On their basis some medical drugs were made, which are widely used in medicine. The aim of this work was the synthesis and study of properties of salts of 5-(2-bromophenyl-4-amino-4H-1,2,4-triazole-3-ylthioacetic acid. Methods and results. As starting material theophylline was selected. Through a number of stages 5-(2-bromphenyl-4-amino-4H-1,2,4-triazole-3-thion was obtained. By the reaction of neutralization the salts with organic and inorganic bases were obtained. The physical-chemical properties of the compounds were determined. The structure of the substances was confirmed by elemental analysis on an Elementar Vario L cube (CHNS instrument; IR spectra (4000–400 cm-1 were taken on the ALPHA-T modules of the Bruker ALPHA FT-IR spectrometer. The 1H NMR spectra of the compounds were recorded using a Varian Mercury VX 200 spectrometer (solvent – DMSO-d6, internal standard: tetramethylsilane. The formation of salts was confirmed by the signals of the corresponding protonated amines. Chromato-mass spectral studies were carried out on the LC MS: Agilent 1260 Infinity HPLC System , ionization method – chemical ionization at atmospheric pressure (APCI. Conclusions. The interaction of the resulting thiol with monochloracetic acid in aqueous solution with double quantity of alkali and subsequent neutralization leads to corresponding carboxylic acid obtaining. It was confirmed that the greatest outputs of salts as the reaction products were observed when using water as the solvent with the subsequent replacement of acetone. the optimum conditions of obtaining salts of 5-(2-bromophenyl-4-amino-4H-1,2,4-triazole-3-ylthioacetic acid

  9. Mixed insoluble acidic salts of tetravalent metals Pt. 5

    International Nuclear Information System (INIS)

    Shakshooki, S.K.; Dehair, A.; Elmismary, Y.; Haraga, S.; Benfaid, N.; Benhamed, A.; Maiof, A.; Szirtes, L.

    1988-01-01

    Solid ZrOCl 2 x8H 2 O was added in a slow stream to a solution of phosphoric acid or to a solution of TiCl 4 in phosphoric acid to obtain granules of amorphous Zr(HPO 4 ) 2 xnH 2 O or Zr x Ti (1-x) (HPO 4 ) 2 xnH-2O (where x=0.95-0.80). It was found that the particle size of the resulting materials is very similar to that of ZrOCl 2 x8H 2 O, in such a way that it may be controlled indirectly. These materials are suitable for ion-exchange column operations. The relatively high gamma radiation doses of 60 Co source did not alter its exchange properties. pH-titrations were performed by an automatic titrimeter and the exchange capacities of alkali metal ions were determined by isotopic tracer technique. Other characterizations were made by usual chemical analysis and thermography. (author) 20 refs.; 4 figs

  10. 77 FR 1455 - Citric Acid and Certain Citrate Salts From the People's Republic of China: Extension of Time...

    Science.gov (United States)

    2012-01-10

    ... DEPARTMENT OF COMMERCE International Trade Administration [A-570-937] Citric Acid and Certain... review of the antidumping duty order on citric acid and certain citrate salts (``citric acid'') from the... practicable to complete the preliminary results of the administrative review of citric acid from the PRC...

  11. 77 FR 22560 - Citric Acid and Certain Citrate Salts From the People's Republic of China: Extension of Time...

    Science.gov (United States)

    2012-04-16

    ... DEPARTMENT OF COMMERCE International Trade Administration [A-570-937] Citric Acid and Certain... review of the antidumping duty order on citric acid and certain citrate salts (``citric acid'') from the... Request for Revocation in Part, 76 FR 37781, 37785 (June 28, 2011). \\2\\ See Citric Acid and Certain...

  12. 76 FR 49735 - Citric Acid and Certain Citrate Salts From the People's Republic of China: Partial Rescission of...

    Science.gov (United States)

    2011-08-11

    ... DEPARTMENT OF COMMERCE International Trade Administration [C-570-938] Citric Acid and Certain... citric acid and certain citrate salts (``citric acid'') from the People's Republic of China (``PRC...., Ltd. (``Xinghua''), a producer and exporter of citric acid, timely requested that the Department...

  13. Synthesis and characterization of silver nanoparticles from (bis)alkylamine silver carboxylate precursors

    Energy Technology Data Exchange (ETDEWEB)

    Uznanski, Pawel, E-mail: puznansk@cbmm.lodz.pl; Zakrzewska, Joanna [Centre of Molecular and Macromolecular Studies, PAS (Poland); Favier, Frederic, E-mail: fredf@univ-montp2.fr [Université Montpellier II, ICGM - UMR5253- Equipe AIME (France); Kazmierski, Slawomir; Bryszewska, Ewa [Centre of Molecular and Macromolecular Studies, PAS (Poland)

    2017-03-15

    A comparative study of amine and silver carboxylate adducts [R{sub 1}COOAg-2(R{sub 2}NH{sub 2})] (R{sub 1} = 1, 7, 11; R{sub 2} = 8, 12) as a key intermediate in NPs synthesis is carried out via differential scanning calorimetry, solid-state FT-infrared spectroscopy, {sup 13}C CP MAS NMR, powder X-ray diffraction and X-ray photoelectron spectroscopy, and various solution NMR spectroscopies ({sup 1}H and {sup 13}C NMR, pulsed field gradient spin-echo NMR, and ROESY). It is proposed that carboxyl moieties in the presence of amine ligands are bound to silver ions via chelating bidentate type of coordination as opposed to bridging bidentate coordination of pure silver carboxylates resulting from the formation of dimeric units. All complexes are packed as lamellar bilayer structures. Silver carboxylate/amine complexes show one first-order melting transition. The evidence presented in this study shows that phase behavior of monovalent metal carboxylates are controlled, mainly, by head group bonding. In solution, insoluble silver salt is stabilized by amine molecules which exist in dynamic equilibrium. Using (bis)amine-silver carboxylate complex as precursor, silver nanoparticles were fabricated. During high-temperature thermolysis, the (bis)amine-carboxylate adduct decomposes to produce silver nanoparticles of small size. NPs are stabilized by strongly interacting carboxylate and trace amounts of amine derived from the silver precursor interacting with carboxylic acid. A corresponding aliphatic amide obtained from silver precursor at high-temperature reaction conditions is not taking part in the stabilization. Combining NMR techniques with FTIR, it was possible to follow an original stabilization mechanism.

  14. Synthesis, characterization and metal coordination of a potential β-lactamase inhibitor: 5-Methyl-2-phenoxymethyl-3-H-imidazole-4-carboxylic acid (PIMA

    Directory of Open Access Journals (Sweden)

    Chiara Romagnoli

    2017-12-01

    Full Text Available Among relevant metal ions in biological systems, zinc and iron play a key role as active partners of the catalytic machinery. In particular, the inhibition of metal enzymes that are involved in physiological and pathological processes has been deeply investigated for the rational design of selective and efficient drugs based on chelators. Since imidazole histidine residue is one of the most versatile sites in proteins, especially in enzymes acting in the presence of metal ions as cofactors, in this work the synthesis and characterization of a new imidazole derivative, namely 5-methyl-2-phenoxymethyl-3-H-imidazole-4-carboxylic acid (PIMA is reported. PIMA was designed as metallo-β-lactamase inhibitor thanks to its similarity with penicillin V, a β-lactam antibiotic inactivated by metallo-β-lactamase, for which there are no commercially available inhibitors. The evaluation of PIMA coordinating ability toward iron, zinc, and gallium, these latter selected as a non-paramagnetic probe for iron, is performed by theoretical DFT calculations and in solution by experimental techniques, i.e. potentiometry, UV–vis and NMR spectroscopy. PIMA exhibits an efficient metal chelating ability; the prevailing species in physiological condition are ML3 for Fe3+ and Ga3+ and ML2 for Zn2+, in which chelation is due to deprotonated carboxylic oxygen and imidazole nitrogen in the N,O donor set. The demonstrated ability of PIMA to chelate zinc ion, combined with its structure similarity with penicillin V, supports further exploration of this imidazole-4-carboxylate as metallo-β-lactamase inhibitor.

  15. Alleviation of salt-induced oxidative damage by 5-aminolevulinic acid in wheat seedlings

    Science.gov (United States)

    Genişel, Mucip; Erdal, Serkan

    2016-04-01

    The aim of this study was to elucidate how 5-aminolevulinic acid (ALA), the precursor of chlorophyll compounds, affects the defence mechanisms of wheat seedlings induced by salt stress. To determine the possible stimulative effects of ALA against salinity, 11-day old wheat seedlings were sprayed with ALA at two different concentrations (10 and 20 mg.l-1) and then stressed by exposure to salt (150 mM NaCl). The salt stress led to significant changes in the antioxidant activity. While guaiacol peroxidase activity decreased, the activities of superoxide dismutase, catalase, and ascorbate peroxidase markedly increased under salt stress. Compared to the salt stress alone, the application of ALA beforehand further increased the activity of these enzymes. This study is the first time the effects of ALA have been monitored with regard to protein content and the isoenzyme profiles of the antioxidant enzymes. Although the salt stress reduced both the soluble protein content and protein band intensities, pre-treating with ALA significantly mitigated these stress-induced reductions. The data for the isoenzyme profiles of the antioxidant enzymes paralleled that of the ALA-induced increases in antioxidant activity. As a consequence of the high antioxidant activity in the seedlings pre-treated with ALA, the stress-induced elevations in the reactive oxygen species, superoxide anion, and hydrogen peroxide contents and lipid peroxidation levels were markedly diminished. Taken together, this data demonstrated that pre-treating with ALA confers resistance to salt stress by modulating the protein synthesis and antioxidant activity in wheat seedlings.

  16. Microarray Analysis of Transcriptional Responses to Abscisic Acid and Salt Stress in Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Yucheng Wang

    2013-05-01

    Full Text Available Abscisic acid (ABA plays a crucial role in plant responses to abiotic stress. To investigate differences in plant responses to salt and ABA stimulus, differences in gene expression in Arabidopsis in response to salt and ABA were compared using an Agilent oligo microarray. A total of 144 and 139 genes were significantly up- and downregulated, respectively, under NaCl stress, while 406 and 381 genes were significantly up- and downregulated, respectively, under ABA stress conditions. In addition, 31 genes were upregulated by both NaCl and ABA stresses, and 23 genes were downregulated by these stressors, suggesting that these genes may play similar roles in plant responses to salt and ABA stress. Gene ontology (GO analysis revealed four subgroups of genes, including genes in the GO categories “Molecular transducer activity”, “Growth”, “Biological adhesion” and “Pigmentation”, which were expressed in response to ABA stress but not NaCl stress. In addition, genes that play specific roles during salt or ABA stress were identified. Our results may help elucidate differences in the response of plants to salt and ABA stress.

  17. Recovery and esterification of aqueous carboxylates by using CO

    NARCIS (Netherlands)

    Cabrera-Rodríguez, Carlos I.; Paltrinieri, Laura; Smet, De Louis C.P.M.; Wielen, Van Der Luuk A.M.; Straathof, Adrie J.J.

    2017-01-01

    The recovery of carboxylic acids from fermentation broth is one of the main bottlenecks for the industrial production of bio-based esters. This paper proposes an alternative for the recovery of carboxylates produced by fermentations at pH values above the pKa of the carboxylic acid. In this

  18. Graft polymerization of acrylic acid and methacrylic acid onto poly(vinylidene fluoride) powder in presence of metallic salt and sulfuric acid

    Science.gov (United States)

    Deng, Bo; Yu, Yang; Zhang, Bowu; Yang, Xuanxuan; Li, Linfan; Yu, Ming; Li, Jingye

    2011-02-01

    Poly(vinylidene fluoride) (PVDF) powder was grafted with acrylic acid (AAc) or methacrylic acid (MAA) by the pre-irradiation induced graft polymerization technique. The presence of graft chains was proven by FT-IR spectroscopy. The degree of grafting (DG) was calculated by the acid-base back titration method. The synergistic effect of acid and Mohr's salt on the grafting kinetics was examined. The results indicated that adding sulfuric acid and Mohr's salt simultaneously in AAc or MAA solutions led to a strong enhancement in the degree of grafting. The grafted PVDF powder was cast into microfiltration (MF) membranes using the phase inversion method and some properties of the obtained MF membranes were characterized.

  19. Graft polymerization of acrylic acid and methacrylic acid onto poly(vinylidene fluoride) powder in presence of metallic salt and sulfuric acid

    Energy Technology Data Exchange (ETDEWEB)

    Deng Bo [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, No. 2019, Jialuo Road, Jiading Dist., 201800 Shanghai (China); Yu Yang; Zhang Bowu; Yang Xuanxuan [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, No. 2019, Jialuo Road, Jiading Dist., 201800 Shanghai (China); Graduate University of Chinese Academy of Sciences, No. 19, Yuquan Road, Shijingshan Dist., 100049 Beijing (China); Li Linfan; Yu Ming [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, No. 2019, Jialuo Road, Jiading Dist., 201800 Shanghai (China); Li Jingye, E-mail: jingyeli@sinap.ac.c [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, No. 2019, Jialuo Road, Jiading Dist., 201800 Shanghai (China)

    2011-02-15

    Poly(vinylidene fluoride) (PVDF) powder was grafted with acrylic acid (AAc) or methacrylic acid (MAA) by the pre-irradiation induced graft polymerization technique. The presence of graft chains was proven by FT-IR spectroscopy. The degree of grafting (DG) was calculated by the acid-base back titration method. The synergistic effect of acid and Mohr's salt on the grafting kinetics was examined. The results indicated that adding sulfuric acid and Mohr's salt simultaneously in AAc or MAA solutions led to a strong enhancement in the degree of grafting. The grafted PVDF powder was cast into microfiltration (MF) membranes using the phase inversion method and some properties of the obtained MF membranes were characterized.

  20. Graft polymerization of acrylic acid and methacrylic acid onto poly(vinylidene fluoride) powder in presence of metallic salt and sulfuric acid

    International Nuclear Information System (INIS)

    Deng Bo; Yu Yang; Zhang Bowu; Yang Xuanxuan; Li Linfan; Yu Ming; Li Jingye

    2011-01-01

    Poly(vinylidene fluoride) (PVDF) powder was grafted with acrylic acid (AAc) or methacrylic acid (MAA) by the pre-irradiation induced graft polymerization technique. The presence of graft chains was proven by FT-IR spectroscopy. The degree of grafting (DG) was calculated by the acid-base back titration method. The synergistic effect of acid and Mohr's salt on the grafting kinetics was examined. The results indicated that adding sulfuric acid and Mohr's salt simultaneously in AAc or MAA solutions led to a strong enhancement in the degree of grafting. The grafted PVDF powder was cast into microfiltration (MF) membranes using the phase inversion method and some properties of the obtained MF membranes were characterized.