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Sample records for acetals carboxylic acids

  1. Benzylidene Acetal Protecting Group as Carboxylic Acid Surrogate: Synthesis of Functionalized Uronic Acids and Sugar Amino Acids.

    Banerjee, Amit; Senthilkumar, Soundararasu; Baskaran, Sundarababu

    2016-01-18

    Direct oxidation of the 4,6-O-benzylidene acetal protecting group to C-6 carboxylic acid has been developed that provides an easy access to a wide range of biologically important and synthetically challenging uronic acid and sugar amino acid derivatives in good yields. The RuCl3 -NaIO4 -mediated oxidative cleavage method eliminates protection and deprotection steps and the reaction takes place under mild conditions. The dual role of the benzylidene acetal, as a protecting group and source of carboxylic acid, was exploited in the efficient synthesis of six-carbon sialic acid analogues and disaccharides bearing uronic acids, including glycosaminoglycan analogues. PMID:26572799

  2. Solvent extraction studies on uranium (VI) with high molecular weight carboxylic acids from acetate medium

    Carboxylic acids are cation exchanger type of extractant which extract metal ions from weak acidic solutions by ion exchange mechanism. They are present as dimer (H2A2) in the non polar organic diluents. High molecular weight carboxylic acids such as versatic 10 acid and naphthenic acid are used for the separation of high purity of yttrium from heavy fraction of rare earths. Extraction behavior of rare earths with different types of carboxylic acids is also reported. Literature survey revealed that the extraction behavior of uranium from aqueous solutions with carboxylic acids is scanty. An attempt has been made in the present work to examine the extraction behavior of U(VI) with three different types of high molecular weight carboxylic acids namely cekanoic acid, neoheptanoic acid and versatic 10 acid dissolved in xylene. Extraction of metal ions is very much dependent on pH of the solution

  3. Required catalytic properties for alkane production from carboxylic acids: Hydrodeoxygenation of acetic acid

    Zhong; He; Xianqin; Wang

    2013-01-01

    The supported Pt catalysts(1 wt%)were prepared by the incipient impregnation method and analyzed using synchrotron-based X-ray diffraction,BET surface area,oxygen adsorption,CO pulse chemisorption,temperature-programmed desorption(TPD)of acetic acid,H2-TPD,NH3-TPD,O2-TPD,and H2-TPR.The reactivity of Pt-based catalysts was studied using a fixed bed reactor at 300 C and 4 MPa for hydrodeoxygenation of acetic acid,where Pt/TiO2 was very selective for ethane production.TPD experiments revealed that several conditions must be satisfied to achieve this high selectivity to ethane from acetic acid,such as Pt sites,moderate acidity,and medium metal-oxygen bond strength in the oxide support.This work provides insights in developing novel catalytic materials for hydrocarbon productions from various organics including bio-fuels.

  4. Metal extraction by amides of carboxylic acids

    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 C7-C9 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

  5. Chemistry and electrochemistry in trifluoroacetic acid. Comparison with acetic acid

    As the trifluoroacetic acid is, with the acetic acid, one of most often used carboxylic acids as solvent, notably in organic chemistry, this research thesis addresses some relatively simple complexing and redox reactions to highlight the peculiar feature of this acid, and to explain its very much different behaviour with respect to acetic acid. The author develops the notion of acidity level in solvents of low dielectric constant. The second part addresses a specific solvent: BF3(CH3COOH)2. The boron trifluoride strengthens the acidity of acetic acid and modifies its chemical and physical-chemical properties. In the third part, the author compares solvent properties of CF3COOH and CH3COOH. Noticed differences explain why the trifluoroacetic acid is a more interesting reaction environment than acetic acid for reactions such as electrophilic substitutions or protein solubilisation

  6. ACETIC ACID AND A BUFFER

    2009-01-01

    The present invention relates to a composition comprising : a) 0.01-20% wt/wt acetic acid and b) a physiologically tolerable buffer capable of maintaining acetic acid at a pH in the range of 2-7; and use of such a composition as an antimicrobial agent.......The present invention relates to a composition comprising : a) 0.01-20% wt/wt acetic acid and b) a physiologically tolerable buffer capable of maintaining acetic acid at a pH in the range of 2-7; and use of such a composition as an antimicrobial agent....

  7. Complicated Composting: Persistent Pyridine Carboxylic Acid Herbicides

    Reimer, Julie

    2013-01-01

    This paper reviews pyridine carboxylic acid herbicide impacts on compost. Pyridine carboxylic acid herbicides are not completely broken down during grass growth, harvest and drying of hay, in the digestive tract of livestock, or during composting. These herbicides are a popular choice for broadleaf weed control because of this persistence: they remain effective for months or years. Pyridine carboxylic acids are also more effective than the common herbicide 2, 4-dichlorophenoxyacetic acid and ...

  8. Structure Property Relationships of Carboxylic Acid Isosteres.

    Lassalas, Pierrik; Gay, Bryant; Lasfargeas, Caroline; James, Michael J; Tran, Van; Vijayendran, Krishna G; Brunden, Kurt R; Kozlowski, Marisa C; Thomas, Craig J; Smith, Amos B; Huryn, Donna M; Ballatore, Carlo

    2016-04-14

    The replacement of a carboxylic acid with a surrogate structure, or (bio)-isostere, is a classical strategy in medicinal chemistry. The general underlying principle is that by maintaining the features of the carboxylic acid critical for biological activity, but appropriately modifying the physicochemical properties, improved analogs may result. In this context, a systematic assessment of the physicochemical properties of carboxylic acid isosteres would be desirable to enable more informed decisions of potential replacements to be used for analog design. Herein we report the structure-property relationships (SPR) of 35 phenylpropionic acid derivatives, in which the carboxylic acid moiety is replaced with a series of known isosteres. The data set generated provides an assessment of the relative impact on the physicochemical properties that these replacements may have compared to the carboxylic acid analog. As such, this study presents a framework for how to rationally apply isosteric replacements of the carboxylic acid functional group. PMID:26967507

  9. Palladium-Catalyzed C–C Bond Formations via Activation of Carboxylic Acids and Their Derivatives

    Song, Bingrui

    2013-01-01

    Applications of carboxylic acids and their derivatives in transition metal-catalyzed cross-coupling reactions regio-selectively forming Csp3-Csp2, and Csp2-Csp2 bonds were explored in this thesis. Several important organic building blocks such as aryl acetates, diaryl acetates, imines, ketones, biaryls, styrenes and polysubstituted alkenes were successfully accessed from carboxylic acids and their derivatives by the means of C–H activation and decarboxylative cross-couplings. An efficient ...

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

    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)

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

    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)

  12. Antibiofilm Properties of Acetic Acid

    Bjarnsholt, Thomas; Alhede, Morten; Jensen, Peter Østrup;

    2014-01-01

    infected implant, tissue, or organ and thereby the biofilm. Acetic acid is known for its antimicrobial effect on bacteria in general, but has never been thoroughly tested for its efficacy against bacterial biofilms. In this article, we describe complete eradication of both Gram-positive and Gram...

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

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

    2011-02-01

    Clouds are multiphasic atmospheric systems in which the dissolved organic compounds, dominated by carboxylic acids, are subject to multiple chemical transformations in the aqueous phase. Among them, solar radiation, by generating hydroxyl radicals (•OH), is considered as the main catalyzer of the reactivity of organic species in clouds. We investigated to which extent the active biomass existing in cloud water represents an alternative route to the chemical reactivity of carboxylic acids. Pure cultures of seventeen bacterial strains (Arthrobacter, Bacillus, Clavibacter, Frigoribacterium, Pseudomonas, Sphingomonas and Rhodococcus), previously isolated from cloud water and representative of the viable community of clouds were first individually incubated in two artificial bulk cloud water solutions at 17 °C and 5 °C. These solutions mimicked the chemical composition of cloud water from "marine" and "continental" air masses, and contained the major carboxylic acids existing in the cloud water (i.e. acetate, formate, succinate and oxalate). The concentrations of these carboxylic compounds were monitored over time and biodegradation rates were determined. In average, they ranged from 2 ×10-19 for succinate to 1 × 10-18 mol cell-1 s-1 for formate at 17 °C and from 4 × 10-20 for succinate to 6 × 10-19 mol cell-1 s-1 for formate at 5 °C, with no significant difference between "marine" and "continental" media. In parallel, irradiation experiments were also conducted in these two artificial media to compare biodegradation and photodegradation of carboxylic compounds. To complete this comparison, the photodegradation rates of carboxylic acids by •OH radicals were calculated from literature data. Inferred estimations suggested a significant participation of microbes to the transformation of carboxylic acids in cloud water, particularly for acetate and succinate (up to 90%). Furthermore, a natural cloud water sample was incubated (including its indigenous microflora

  14. Novel Polymers with Carboxylic Acid Loading

    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...

  15. Crystal structure of febuxostat–acetic acid (1/1

    Min Wu

    2015-05-01

    Full Text Available The asymmetric unit of the title compound [systematic name: 2-(3-cyano-4-isobutyloxyphenyl-4-methylthiazole-5-carboxylic acid–acetic acid (1/1], C16H16N2O3S·CH3COOH, contains a febuxostat molecule and an acetic acid molecule. In the febuxostat molecule, the thiazole ring is nearly coplanar with the benzene ring [dihedral angle = 3.24 (2°]. In the crystal, the febuxostat and acetic acid molecules are linked by O—H...O, O—H...N hydrogen bonds and weak C—H...O hydrogen bonds, forming supramolecular chains propagating along the b-axis direction. π–π stacking is observed between nearly parallel thiazole and benzene rings of adjacent molecules; the centroid-to-centroid distances are 3.8064 (17 and 3.9296 (17 Å.

  16. Beyond ketonization: selective conversion of carboxylic acids to olefins over balanced Lewis acid–base pairs

    Baylon, Rebecca A. L.; Sun, Junming; Martin, Kevin J.; Venkitasubramanian, Padmesh; Wang, Yong

    2016-01-01

    Dwindling petroleum reserves combined with increased energy demand and political factors encouraging an increase in energy independence have led to a large amount of research on sustainable alternatives. To this end, biomass conversion has been recognized as themost readily viable technology to produce biofuel concerning our reliance on liquid fuels for transportation and has the advantage of being easily integrated into our heavy use of combustion engines. The interest in biomass conversion has also resulted in reduced costs and a greater abundance of bio-oil, a mixture of hundreds of oxygenates including alcohols, aldehydes, carboxylic acids, and ketones. However, the presence of carboxylic acids in bio-oil derived from lignocellulose pyrolysis leads to low pH, instability, and corrosiveness. In addition, carboxylic acids (i.e. acetic acid) can also be produced via fermentation of sugars. This can be accomplished by a variety of homoacetogenic microorganisms that can produce acetic acid with 100% carbon yield.

  17. Production of carboxylic acid and salt co-products

    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.

  18. 40 CFR 721.2950 - Carboxylic acid glycidyl esters.

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Carboxylic acid glycidyl esters. 721... Substances § 721.2950 Carboxylic acid glycidyl esters. (a) Chemical substances and significant new uses subject to reporting. (1) The chemical substance identified generically as carboxylic acid glycidyl...

  19. Low-molecular-weight carboxylic acids produced from hydrothermal treatment of organic wastes.

    Quitain, Armando T; Faisal, Muhammad; Kang, Kilyoon; Daimon, Hiroyuki; Fujie, Koichi

    2002-07-22

    This article reports production of low-molecular-weight carboxylic acids from the hydrothermal treatment of representative organic wastes and compounds (i.e. domestic sludge, proteinaceous, cellulosic and plastic wastes) with or without oxidant (H(2)O(2)). Organic acids such as acetic, formic, propionic, succinic and lactic acids were obtained in significant amounts. At 623 K (16.5 MPa), acetic acid of about 26 mg/g dry waste fish entrails was obtained. This increased to 42 mg/g dry waste fish entrails in the presence of H(2)O(2). Experiments on glucose to represent cellulosic wastes were also carried out, getting acetic acid of about 29 mg/g glucose. The study was extended to terephthalic acid and glyceraldehyde, reaction intermediates of hydrothermal treatment of polyethylene terephthalate (PET) plastic wastes and glucose, respectively. In addition, production of lactic acid, one of the interesting low-molecular-weight carboxylic acids, was discussed on the viewpoint of resources recovery. Studies on temperature dependence of formation of organic acids showed thermal stability of acetic acid, whereas, formic acid decomposed readily under hydrothermal conditions. In general, results demonstrated that the presence of oxidants favored formation of organic acids with acetic acid being the major product. PMID:12117467

  20. Acetic acid extraction from aqueous solutions using fatty acids

    IJmker, H.M.; Gramblicka, M.; Kersten, S.R.A.; Ham, van der A.G.J.; Schuur, B.

    2014-01-01

    A major challenge for production of acetic acid via bio-based routes is cost-effective concentration and purification of the acetic acid from the aqueous solutions, for which liquid–liquid extraction is a possible method. A main challenge in extraction of acetic acid from dilute aqueous solutions is

  1. Direct Oxidation of Ethene to Acetic Acid

    2001-01-01

    Direct oxidation of ethene to acetic acid over Pd-SiW12/SiO2 catalysts prepared by several methods was studied. A better method for reducing palladium composition of the catalysts was found. Acetic acid was obtained with selectivity of 82.7% and once-through space time yield (STY) of 257.4 g/h×L.

  2. Protection of historical lead against acetic acid vapour

    Pecenová Z.

    2016-03-01

    Full Text Available Historical lead artefacts (small figurines, appliques, bull (metal seal can be stored in depository and archives in inconvenient storage conditions. The wooden show-case or paper packagings release volatile organic compound to the air during their degradation. These acids, mainly acetic acid are very corrosive for lead. The thin layer of corrosion products which slows atmospheric corrosion is formed on lead surface in atmospheric condition. In presence of acetic acid vapour the voluminous corrosion products are formed and fall off the surface. These corrosion products do not have any protection ability. The lead could be protected against acid environment by layer of “metal soup” which is formed on surface after immersion in solution of salt of carboxylic acid for 24 hours. The solutions of acids (with vary long of carbon chain and their salts are examined. Longer carbon chain provides better efficiency convers layer. The disadvantages are low solubility of carboxylic acids in water and bad abrasion resistance of formed layer.

  3. Carboxylic Acid Esters as Substrates of Cholinesterases

    Brestkin, A. P.; Rozengart, E. V.; Abduvakhabov, A. A.; Sadykov, A. A.

    1983-10-01

    Data on the kinetics of the hydrolysis of various carboxylic acid esters by two main types of cholinesterases — acetylcholinesterase from human erythrocytes and butyrylcholinesterase from horse blood serum — are surveyed. It is shown that the rate of enzyme hydrolysis depends significantly on the structure of the acyl part of the ester molecule, the nature of the ester heteroatom, the structure of the alcohol component, and particularly the structure of the onium group. Esters based on natural products are of special interest as specific substrates of these enzymes. The role of the productive and non-productive sorption of the substrates in enzyme catalysis is demonstrated. The bibliography includes 81 references.

  4. 2-(Carboxymethylsulfanylpyridine-3-carboxylic acid monohydrate

    Xiao-Juan Wang

    2010-06-01

    Full Text Available The title compound, C8H7NO4S·H2O, was obtained by reaction of 2-mercaptopyridine-3-carboxylic acid with chloroacetic acid. In the molecular structure, the dihedral angle between the two least-squares planes defined by the pyridine ring and the carboxy group is 8.32 (9°. The carboxymethylsulfanyl group makes a torsion angle of 82.64 (12° with the pyridine ring. An intramolecular O—H...N hydrogen bond between the acidic function of the carboxymethylsulfanyl group and the pyridine N atom stabilizes the conformation, whereas intermolecular O—H...O hydrogen bonding with the uncoordinated water molecules is responsible for packing of the structure, leading to chains propagating in [001].

  5. Contamination of Acetic and Formic Acids in Water and Its Implications for the Study of Carboxylic Acids in Snow and Ice%超纯水中甲酸、乙酸污染的实验研究及其对雪冰有机酸测定的意义

    姚檀栋; 孙维贞; 蒲健长; 田立德; 焦克勤

    2000-01-01

    the carboxylic acids. The acetic acid contamination due to thermal plastic seal is about 18 times higher than that of formic acid under the same conditions. Additionally, the air is another contributor of formic acid and acetic acid to water samples, the contamination of which are much less than of the plastic bag. Consequently, the study of the carboxylic acids in snow and ice must avoid the plastic containers, especially the polyethylene bags, in the processes of sample preparations.

  6. Acidity of carboxylic acids: a rebuttal and redefinition

    Exner, Otto; Čársky, Petr

    2001-01-01

    Roč. 123, č. 39 (2001), s. 9564-9570. ISSN 0002-7863 R&D Projects: GA ČR GA203/99/1454 Institutional research plan: CEZ:AV0Z4055905 Keywords : carboxylic acids Subject RIV: CC - Organic Chemistry Impact factor: 6.079, year: 2001

  7. Selective esterification of non-conjugated carboxylic acids in the presence of conjugated or aromatic carboxylic acids over active carbon supported methanesulfonic acid

    2008-01-01

    Non-conjugated carboxylic acids are selectively esterified in good yields in the presence of conjugated or aromatic carboxylic acids by stirring over active carbon supported methanesulfonic acid in di-chloromethane at room temperature.

  8. Dissimilation of carbon monoxide to acetic acid by glucose-limited cultures of Clostridium thermoaceticum

    Clostridium thermoaceticum was cultivated in glucose-limited media, and the dissimilation of CO to acetic acid was evaluated. The authors found that cultures catalyzed the rapid dissimilation of CO to acetic acid and CO2, with the stoichiometry obtained for conversion approximating that predicted from the following reaction: 4CO + 2H2O → CH3CO2H + 2CO2. Growing cultures formed approximately 50 mmol (3 g) of CO-derived acetic acid per liter of culture, with the rate of maximal consumption approximating 9.1 mmol of CO consumed/h per liter of culture. In contrast, resting cells were found not to dissimilate CO to acetic acid. 14CO was incorporated, with equal distribution between the carboxyl and methyl carbons of acetic acid when the initial cultivation gas phase was 100% CO whereas 14CO2 preferentially entered the carboxyl carbon when the initial gas phase was 100% CO2. Significantly, in the presence of saturating levels of CO, 14CO2 preferentially entered the methyl carbon, whereas saturating levels of CO2 yielded 14CO-derived labeling predominantly in the carboxyl carbon. These findings are discussed in relation to the path of carbon flow to acetic acid

  9. Applications of Carboxylic Acid Reductases in Oleaginous Microbes

    Resch, Michael G.; Linger, Jeffrey; McGeehan, John; Tyo, Keith; Beckham, Gregg

    2016-04-24

    Carboxylic acid reductases (CARs) are recently emerging reductive enzymes for the direct production of aldehydes from biologically-produced carboxylic acids. Recent work has demonstrated that these powerful enzymes are able to reduce a very broad range of volatile- to long-chain fatty acids as well as aromatic acids. Here, we express four CAR enzymes from different fungal origins to test their activity against fatty acids commonly produced in oleaginous microbes. These in vitro results will inform metabolic engineering strategies to conduct mild biological reduction of carboxylic acids in situ, which is conventionally done via hydrotreating catalysis at high temperatures and hydrogen pressures.

  10. Boron-containing amino carboxylic acid compounds and uses thereof

    Novel compounds which are useful for boron neutron capture therapy (BNCT) are disclosed. The compounds comprise a stable boron-containing group and an aminocycloalkane carboxylic acid group or a boronated acyclic hydrocarbon-linked amino carboxylic acid. Methods for synthesis of the compounds and for use of the compounds in BNCT are disclosed

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

    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

  12. CATALYTIC ESTERIFICATION OF CARBOXYLIC ACIDS WITH ALCOHOLS BY SULFO—POLYVINYL CHLORIDE

    YuShanxin; ZHAOZongbao; 等

    1993-01-01

    Polyvinyl Chloride reacted with chlorosulfonic acid to from a polymer catalyst PVC-SO3H.This polymer catalyst was found to have high activity for resterification reaction between carboxylic acids and alcohols.This paper deals with the conditions in synthesis of n-butlyacetate catalyzed with PVC-SO3H.The PVC-SO3H was used as a catalyst for preparing 11 esters of acetic acid,propionic acid and butyric acid with the yields of 82-92%.

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

    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 the

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

    R.L. Ames

    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

  15. Hydrolytic activity of -alkoxide/acetato-bridged binuclear Cu(II) complexes towards carboxylic acid ester

    Weidong Jiang; Bin Xu; Zhen Xiang; Shengtian Huang; Fuan Liu; Ying Wang

    2013-09-01

    Two -alkoxide/acetate-bridged small molecule binuclear copper(II) complexes were synthesized, and used to promote the hydrolysis of a classic carboxylic acid ester, -nitrophenyl picolinate (PNPP). Both binuclear complexes exhibited good hydrolytic reactivity, giving rise to . 15547- and 17462-fold acceleration over background value for PNPP hydrolysis at neutral conditions, respectively. For comparing, activities of the other two mononuclear analogues were evaluated, revealing that binuclear complexes show approximately 150- and 171-fold kinetic advantage over their mononuclear analogues.

  16. Structural and thermal properties of carboxylic acid functionalized polythiophenes

    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.

  17. Biodegradation of cycloalkane carboxylic acids in oil sand tailings

    The biodegradation of both an n-alkane and several carboxylated cycloalkanes was examined experimentally within tailings produced by the extraction of bitumen from the Athabasca oil sands. The carboxylated cycloalkanes examined were structurally similar to naphthenic acids that have been associated with the acute toxicity of oil sand tailings. The biodegradation potential of naphthenic acids was estimated by determining the biodegradation of both the carboxylated cycloalkanes and hexadecane in oil sand tailings. Carboxylated cycloalkanes were biodegraded within oil sands tailings, although compounds with methyl substitutions on the cycloalkane ring were more resistant to microbial degradation. Microbial activity against hexadecane and certain carboxylated cycloalkanes was found to be nitrogen and phosphorus limited. 21 refs., 3 refs., 1 tab

  18. Biomimetic Decarboxylation of Carboxylic Acids with PhI(OAc)2 Catalyzed by Manganese Porphyrin [Mn(TPP)OAcl

    GHOLAM REZA Karimipour; ROXANA Ahmadpour

    2008-01-01

    Manganese(Ⅲ) meso-tetraphenylporphyrin acetate [Mn(TPP)OAc] served as an effective catalyst for the oxidative decarboxylation of carboxylic acids with (diacetoxyiodo)benzene [Phl(OAc)2] in CH2C12-H2O(95:5,volume ratio),The aryl substituted acetic acids are more reactive than the less electron rich linear carboxylic acids in the presence of catalyst Mn(TPP)OAc,In the former case,the formation of carbonyl products was complete within just a few minutes with >97% selectivities,and no further oxidation of the produced aldehydes was achieved under these catalytic conditions,This method provides a benign procedure owing to the utilization of low toxic(diacetoxyiodo)benzene,biologically relevant manganese porphyrins,and carboxylic acids.

  19. Novel Polymers with a High Carboxylic Acid Loading

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

    2006-01-01

    ABSTRACT: 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 conucted 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-hydroxystyrene-co-methyl methacrylate), and poly(4-hydroxy- styrene-b-styrene)-----have been quantitatively transformed into oxypropynes by the use of either Williamson nr Mitsunobu strategies and subsequently reacted with the azido carboxylic acids. Detailed differential scanning calorimetry...

  20. Carboxylation and Decarboxylation of Aluminum Oxide Nanoparticles Using Bifunctional Carboxylic Acids and Octylamine

    Shirin Alexander

    2016-01-01

    Full Text Available The carboxylation of alumina nanoparticles (NPs, with bifunctional carboxylic acids, provides molecular anchors that are used for building more complexed structures via either physisorption or chemisorption. Colloidal suspensions of the NPs may be prepared by covalently bonding a series of carboxylic acids with secondary functional groups (HO2C-R-X to the surface of the NPs: lysine (X = NH2, p-hydroxybenzoic acid (X = OH, fumaric acid (X = CO2H, and 4-formylbenzoic acid (X = C(OH. Subsequent reaction with octylamine at either 25°C or 70°C was investigated. Fourier transform IR-attenuated reflectance spectroscopy (FTIR-ATR, thermogravimetric analysis (TGA, and scanning electron microscopy (SEM along with energy dispersive X-ray (EDX analysis were used to characterize the bifunctionalized monolayers and/or multilayer corona surrounding the alumina NPs and investigate the reaction mechanism of octylamine with the functional groups (X of the NPs. Except for the fumaric functionalized NPs, addition of octylamine to the functionalized NPs leads to removal of excess carboxylic acid corona from the surface via an amide formation. The extent of the multilayer is dependent on the strength of the acid⋯acid interaction.

  1. Palladium-Catalyzed α-Arylation of Aryl Acetic Acid Derivatives via Dienolate Intermediates with Aryl Chlorides and Bromides

    Sha, Sheng-Chun; Zhang, Jiadi; Walsh, Patrick J.

    2015-01-01

    To date, examples of α-arylation of carboxylic acids remain scarce. Using a deprotonative cross-coupling process (DCCP), a method for palladium-catalyzed γ-arylation of aryl acetic acids with aryl halides has been developed. This protocol is applicable to a wide range of aryl bromides and chlorides. A procedure for the palladium-catalyzed α-arylation of styryl acetic acids is also described.

  2. Overview on mechanisms of acetic acid resistance in acetic acid bacteria.

    Wang, Bin; Shao, Yanchun; Chen, Fusheng

    2015-02-01

    Acetic acid bacteria (AAB) are a group of gram-negative or gram-variable bacteria which possess an obligate aerobic property with oxygen as the terminal electron acceptor, meanwhile transform ethanol and sugar to corresponding aldehydes, ketones and organic acids. Since the first genus Acetobacter of AAB was established in 1898, 16 AAB genera have been recorded so far. As the main producer of a world-wide condiment, vinegar, AAB have evolved an elegant adaptive system that enables them to survive and produce a high concentration of acetic acid. Some researches and reviews focused on mechanisms of acid resistance in enteric bacteria and made the mechanisms thoroughly understood, while a few investigations did in AAB. As the related technologies with proteome, transcriptome and genome were rapidly developed and applied to AAB research, some plausible mechanisms conferring acetic acid resistance in some AAB strains have been published. In this review, the related mechanisms of AAB against acetic acid with acetic acid assimilation, transportation systems, cell morphology and membrane compositions, adaptation response, and fermentation conditions will be described. Finally, a framework for future research for anti-acid AAB will be provided. PMID:25575804

  3. Kinetic and Thermodynamic Parameters for Uncatalyzed Esterification of Carboxylic Acid

    Kehinde S. Bankole

    2014-06-01

    Full Text Available A fundamental study on uncatalyzed esterification of various biomass-derived aliphatic carboxylic acids with stoichiometric amount of ethanol has been investigated in an isothermal batch reactor, with the objective to convert carboxylic acids to corresponding ethyl esters and to determine both the kinetic and thermodynamic parameters. The effects of temperature on the conversion of carboxylic acid, kinetic and thermodynamic parameters have been investigated. Temperature was found to have significant effect on the rate of reaction and conversion of carboxylic acid. A simple second order reversible kinetic model was developed to determine the kinetic and thermodynamic parameters. The thermodynamic and kinetic parameters varied for uncatalyzed esterification reaction of both short-chain and long-chain carboxylic acids considered. The predicted data from the kinetic model were correlated with experimental data and the two sets of data agreed reasonably well for the uncatalyzed esterification systems. It was observed that the Van’t Hoff plot for uncatalyzed esterification of linoleic acid was non-linear curve, whereas for the Arrhenius and Eyring plots, they were linear. Additional experiments to assess the catalytic and corrosion effects of several metallic substances revealed Inconel 625 alloy, nickel wire and stainless steel materials were susceptible to corrosion problem with uncatalyzed esterification reaction at elevated reaction temperatures. However, tantalum and grade-5 titanium materials were corrosion resistance metals, suitable for similar reaction conditions and this can encourage the design of a flow reactor system. Although, uncatalyzed esterification of carboxylic acids at elevated reaction temperature is still at laboratory scale. It is our hope that the estimated kinetic and thermodynamic parameters would be the guiding tools for reactor scale-up, thus providing a new perspective into the conversion of biomass-derived carboxylic

  4. Pyrazine Carboxylic Acid Derivatives of Dichlorobis(Cyclopentadienyltitanium(IV

    Satish Chandra Dixit

    2012-07-01

    Full Text Available Reactions of dichlorobis(cyclopentadienyltitanium(IV with pyrazine carboxylic acids viz. 2-pyrazine carboxylic acid (2-PzCH, 5-methyl-2-pyrazine carboxylic acid (MPzCH and 2,3-pyrazine dicarboxylic acid (2,3-PzDCH2 were carried out in different stoichiometric ratios. Complexes of the type Cp2Ti(2-PzCCl , Cp2Ti(2-PzC2 ,Cp2Ti(MPzCCl,Cp2Ti(MPzC2, Cp2Ti(2,3-PzDCHCl and Cp2Ti(2,3-PzDCH2 were obtained. These newly synthesized complexes were characterized on the basis of elemental analyses, electrical conductance, magnetic moment and spectral data.

  5. Pyrazine Carboxylic Acid Derivatives of Dichlorobis(Cyclopentadienyl)titanium(IV)

    Satish Chandra Dixit; Rohit Kumar Singh

    2012-01-01

    Reactions of dichlorobis(cyclopentadienyl)titanium(IV) with pyrazine carboxylic acids viz. 2-pyrazine carboxylic acid (2-PzCH), 5-methyl-2-pyrazine carboxylic acid (MPzCH) and 2,3-pyrazine dicarboxylic acid (2,3-PzDCH2) were carried out in different stoichiometric ratios. Complexes of the type Cp2Ti(2-PzC)Cl , Cp2Ti(2-PzC)2 ,Cp2Ti(MPzC)Cl,Cp2Ti(MPzC)2, Cp2Ti(2,3-PzDCH)Cl and Cp2Ti(2,3-PzDCH)2 were obtained. These newly synthesized complexes were characterized on the basis of elemental analyse...

  6. Radiolysis of carboxylic acids adsorbed in clay minerals

    This research is aimed at studying the effect of ionizing radiation in an heterogeneous system formed by a carboxylic acid adsorbed in a clay mineral. The study is focussed to discriminate if the presence of a solid surface alters the formation and distribution of radiolytic products in relation to the radiolysis of the carboxylic acid without the surface (clay). The results showed that the radiolysis of the system clay-acid goes along a defined path rather than showing various pathways of decomposition as in the case of simple aqueous solutions. The main pathway was the decarboxylation of the target compound rather than condensation/dimerization reactions

  7. Adaptation and tolerance of bacteria against acetic acid.

    Trček, Janja; Mira, Nuno Pereira; Jarboe, Laura R

    2015-08-01

    Acetic acid is a weak organic acid exerting a toxic effect to most microorganisms at concentrations as low as 0.5 wt%. This toxic effect results mostly from acetic acid dissociation inside microbial cells, causing a decrease of intracellular pH and metabolic disturbance by the anion, among other deleterious effects. These microbial inhibition mechanisms enable acetic acid to be used as a preservative, although its usefulness is limited by the emergence of highly tolerant spoilage strains. Several biotechnological processes are also inhibited by the accumulation of acetic acid in the growth medium including production of bioethanol from lignocellulosics, wine making, and microbe-based production of acetic acid itself. To design better preservation strategies based on acetic acid and to improve the robustness of industrial biotechnological processes limited by this acid's toxicity, it is essential to deepen the understanding of the underlying toxicity mechanisms. In this sense, adaptive responses that improve tolerance to acetic acid have been well studied in Escherichia coli and Saccharomyces cerevisiae. Strains highly tolerant to acetic acid, either isolated from natural environments or specifically engineered for this effect, represent a unique reservoir of information that could increase our understanding of acetic acid tolerance and contribute to the design of additional tolerance mechanisms. In this article, the mechanisms underlying the acetic acid tolerance exhibited by several bacterial strains are reviewed, with emphasis on the knowledge gathered in acetic acid bacteria and E. coli. A comparison of how these bacterial adaptive responses to acetic acid stress fit to those described in the yeast Saccharomyces cerevisiae is also performed. A systematic comparison of the similarities and dissimilarities of the ways by which different microbial systems surpass the deleterious effects of acetic acid toxicity has not been performed so far, although such exchange

  8. Surface chemical properties of sodium salts of carboxylic acids isolated from Green River shale. [Sodium carboxylates

    McKay, J.F.; Blanche, M.S.; Robertson, R.E.

    1985-12-01

    Organic material isolated from Green River shale varies substantially with the method of isolation. Short-time supercritical fluid treatment and solvent extraction of Green River shale produces large amounts of sodium carboxylates. These sodium salts were observed to form emulsions and therefore be surface active. Quantitative surface activity measurements were then determined using the shale extract. The material was found to have a limiting surface tension of about 41 dynes/cm (as expected) for carboxylates. However, the critical micelle concentration is quite high and has a measured molecular weight value of 600. This probably results from higher solubility of the lower molecular weight species. The solution did not display hysteresis. In general the carboxylic acid salts isolated from Green River shale displayed surface activity similar to those of model compounds cited in the literature.

  9. [Degradation of oxytetracycline with ozonation in acetic acid solvent].

    Li, Shi-Yin; Li, Xiao-Rong; Zhu, Yi-Ping; Zhu, Jiang-Peng; Wang, Guo-Xiang

    2012-12-01

    Use acetic acid as the media of ozone degradation of oxytetracycline (OTC), and effects of the initial dosing ratio of ozone/OTC, ozone flow, free radical scavenger, metal ions on the removal rate of OTC were investigated respectively. The results showed that acetic acid had a high ozone stability and solubility. OTC had a high removal rate and degradation rate in acetic acid solution. With the increase of OTC dosage, the removal rate of OTC decreased in acetic acid. Removal rate of OTC was increased distinctly when ozone flow increased properly. It was also observed that free radical scavenger had a significantly negative effect on OTC ozonation degradation in acetic acid. Furthermore the main reactions of OTC ozone oxidation were direct oxidation and indirect oxidation in acetic acid. When Fe3+ and Co2+ were existent in acetic acid, the degradation of OTC was inhibited significantly. PMID:23379161

  10. The Microwave-assisted Preparation and X-Ray Structure of 3-Bromocarbazole-N-Acetic Acid

    2001-01-01

    The rapid synthesis of 3-bromocarbazole-N-acetic acid was performed using microwave irradiation. Under the optimal conditions the yield was 85.6 %. The crystal structure showed that the carboxylic groups form bifurcated hydrogen bonds and the hydroxyl oxygen atoms serve as proton donors and also acceptor. Each carboxylic group was involved in four hydrogen bonds. The packing of crystal was dominated by links of these hydrogen bonds.

  11. More on Effects Controlling Carboxylic Acidity.

    Schwartz, Lowell M.

    1981-01-01

    Gas phase acidity data shown are offered to writers of elementary organic chemistry texts for replacement of the aqueous phase data that are universally used. Relative acidities in the gas phase are controlled virtually exclusively by enthalpic factors. Structural-energetic explanations of acidic trends can therefore be used. (SK)

  12. Importance of secondary sources in the atmospheric budgets of formic and acetic acids

    F. Paulot

    2010-10-01

    Full Text Available We present a detailed budget of formic and acetic acids, two of the most abundant trace gases in the atmosphere. Our bottom-up estimate of the global source of formic and acetic acids are ~1200 and ~1400 Gmol/yr, dominated by photochemical oxidation of biogenic volatile organic compounds, in particular isoprene. Their sinks are dominated by wet and dry deposition. We use the GEOS-Chem chemical transport model to evaluate this budget against an extensive suite of measurements from ground, ship and satellite-based Fourier transform spectrometers, as well as from several aircraft campaigns over North America. The model captures the seasonality of formic and acetic acids well but generally underestimates their concentration, particularly in the Northern midlatitudes. We infer that the source of both carboxylic acids may be up to 50% greater than our estimate and report evidence for a long-lived missing secondary source of carboxylic acids that may be associated with the aging of organic aerosols. Vertical profiles of formic acid in the upper troposphere support a negative temperature dependence of the reaction between formic acid and the hydroxyl radical as suggested by several theoretical studies.

  13. Conformation of some carboxylic acids and their derivatives

    Kanters, J.A.; Kroon, Jan; Peerdeman, A.F.; Schoone, J.C.

    1967-01-01

    The conformation in the crystalline state of some aliphatic carboxylic acids and their derivatives has been analysed. This analysis, based upon the results of structure determinations by means of X-ray diffraction, seems to support the concept that the conformation of a molecule is governed chiefly

  14. Formic and acetic acid: Valence threshold photoelectron and photoionisation total ion yield studies

    Highlights: ► High-resolution threshold photoelectron spectrum of formic acid. ► High-resolution total photo-ion yield spectrum of formic acid. ► High-resolution threshold photoelectron spectrum of acetic acid. ► High-resolution total photo-ion yield spectrum of acetic acid. -- Abstract: The carboxylic acids (formic and acetic) have been studied using threshold photoelectron (TPE) and total photoion yield (TPIY) spectroscopies; simultaneously obtained spectra of formic acid (HCOOH) were recorded over the entire valence ionisation region from 11–21 eV at a resolution of ∼12 meV. Higher resolution spectra (∼6 meV) were also obtained in the energy region of the lowest two cationic states. Analysis of the TPE spectrum in this energy range agreed very favorably with the best available conventional photoelectron (PE) spectrum of formic acid. Autoionising Rydberg structure was observed in the TPIY spectrum of formic acid and is attributed primarily to the presence of the npa′ ← 8a′ Rydberg series converging on to the 32A′ ionic state of formic acid. Preliminary results, at a resolution of ∼8 meV, were obtained for acetic acid (CH3COOH) over the onset of the ionisation energy region. The TPE spectrum was found to be very similar to the best published photoelectron spectrum, but no Rydberg structure was observed in the TPIY spectrum.

  15. Enhance decarboxylation reaction of carboxylic acids in clay minerals

    Clay minerals are important constituents of the Earth's crust. These minerals catalyze reactions in several ways: by energy transfer processes, redox reactions, stabilization of intermediates and by Broensted or Lewis acidity behavior. Important set of organic reactions can be improved in the precedence of clay minerals. Besides the properties of clays to catalyze chemical reactions, it is possible to enhance some of its reactions by using ionizing radiation. The phenomenon of radiation-induced catalysis may be connected with ionizing process in the solid and with the trapped non-equilibrium charge carriers. In this paper we are reporting the decarboxylation reaction of carboxylic acids catalyzed by clay and by irradiation of the system acid-clay. We studied the behaviour of several carboxylic acids and analyzed them by gas chromatography, X-ray and infrared spectroscopy. The results showed that decarboxylation of the target compound is the dominating pathway. The reaction is enhanced by gamma radiation in several orders of magnitude. (author)

  16. Extraction of scandium by aromatic carboxylic acids

    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

  17. Oxidation of indole-3-acetic acid to oxindole-3-acetic acid by an enzyme preparation from Zea mays

    Reinecke, D. M.; Bandurski, R. S.

    1988-01-01

    Indole-3-acetic acid is oxidized to oxindole-3-acetic acid by Zea mays tissue extracts. Shoot, root, and endosperm tissues have enzyme activities of 1 to 10 picomoles per hour per milligram protein. The enzyme is heat labile, is soluble, and requires oxygen for activity. Cofactors of mixed function oxygenase, peroxidase, and intermolecular dioxygenase are not stimulatory to enzymic activity. A heat-stable, detergent-extractable component from corn enhances enzyme activity 6- to 10-fold. This is the first demonstration of the in vitro enzymic oxidation of indole-3-acetic acid to oxindole-3-acetic acid in higher plants.

  18. 40 CFR 721.4663 - Fluorinated carboxylic acid alkali metal salts.

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Fluorinated carboxylic acid alkali... 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...

  19. 40 CFR 721.10142 - Oxabicycloalkane carboxylic acid alkanediyl ester (generic).

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Oxabicycloalkane carboxylic acid... New Uses for Specific Chemical Substances § 721.10142 Oxabicycloalkane carboxylic acid alkanediyl... substance identified generically as oxabicycloalkane carboxylic acid alkanediyl ester (PMN P-06-199)...

  20. Green process for chemical functionalization of nanocellulose with carboxylic acids.

    Espino-Pérez, Etzael; Domenek, Sandra; Belgacem, Naceur; Sillard, Cécile; Bras, Julien

    2014-12-01

    An environmentally friendly and simple method, named SolReact, has been developed for a solvent-free esterification of cellulose nanocrystals (CNC) surface by using two nontoxic carboxylic acids (CA), phenylacetic acid and hydrocinnamic acid. In this process, the carboxylic acids do not only act as grafting agent, but also as solvent media above their melting point. Key is the in situ solvent exchange by water evaporation driving the esterification reaction without drying the CNC. Atomic force microscopy and X-ray diffraction analyses showed no significant change in the CNC dimensions and crystallinity index after this green process. The presence of the grafted carboxylic was characterized by analysis of the "bulk" CNC with elemental analysis, infrared spectroscopy, and (13)C NMR. The ability to tune the surface properties of grafted nanocrystals (CNC-g-CA) was evaluated by X-ray photoelectron spectroscopy analysis. The hydrophobicity behavior of the functionalized CNC was studied through the water contact-angle measurements and vapor adsorption. The functionalization of these bionanoparticles may offer applications in composite manufacturing, where these nanoparticles have limited dispersibility in hydrophobic polymer matrices and as nanoadsorbers due to the presence of phenolic groups attached on the surface. PMID:25353612

  1. Isobaric Vapor-Liquid Equilibrium of Binary Systems: p-Xylene + (Acetic Acid, Methyl Acetate and n-Propyl Acetate)and Methyl Acetate + n-Propyl Acetate in an Acetic Acid Dehydration Process

    HUANG Xiuhui; ZHONG Weimin; PENG Changjun; QIAN Feng

    2013-01-01

    The vapor-liquid equilibrium data of four binary systems(acetic acid + p-xylene,methyl acetate + n-propyl acetate,n-propyl acetate + p-xylene and methyl acetate + p-xylene)are measured at 101.33 kPa with Ellis equilibrium still,and then both the NRTL and UNIQUAC models are used in combination with the HOC model for correlating and estimating the vapor-liquid equilibrium of these four binary systems.The estimated binary VLE results using correlated parameters agree well with the measured data except the methyl acetate + p-xylene system which easily causes bumping and liquid rushing out of the sampling tap due to their dramatically different boiling points.The correlation results by NRTL and UNIQUAC models have little difference on the average absolute deviations of temperature and composition of vapor phase,and the results by NRTL model are slightly better than those by UNIQUAC model except for the methyl acetate + n-propyl acetate system,for which the latter gives more accurate correlations.

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

    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...

  3. Sodium borohydride reduction of aromatic carboxylic acids via methyl esters

    Aamer Saeed; Zaman Ashraf

    2006-09-01

    A number of important aromatic carboxylic acids precursors, or intermediates in the syntheses of natural products, are converted into methyl esters and reduced to the corresponding primary alcohols using a sodium borohydride-THF-methanol system. The alcohols are obtained in 70-92% yields in 2-5 hours, in a pure state. This two-step procedure not only provides a better alternative to aluminum hydride reduction of acids but also allows the selective reduction of esters in presence of acids, amides, nitriles or nitro functions which are not affected under these conditions.

  4. Toxicity of perfluorinated carboxylic acids for aquatic organisms.

    Tichý, Miloň; Valigurová, Radka; Cabala, Radomír; Uzlová, Rut; Rucki, Marián

    2010-06-01

    Toxicity of perfluorinated carboxylic acids with carbon chain C(8) to C(12) were tested with oligochaeta Tubifex tubifex. Toxicity was evaluated as the exposure time ET(50) from onset of damage of the oligochaeta in saturated aqueous solutions. The ET(50) fluctuated between 25 and 257 minutes. No statistically significant difference was found among the C(8), C(9) and C(12) acids (ET(50) between 143 and 257 minutes with large standard deviation). The acids with carbon chain C(10) and C(11) induced the effect significantly quicker (25 to 47 minutes). No acute toxicity measured in the three-minute test was observed in any case. PMID:21217876

  5. Toxicity of perfluorinated carboxylic acids for aquatic organisms

    Tichý, Miloň; Valigurová, Radka; Čabala, Radomír; Uzlová, Rut; Rucki, Marián

    2010-01-01

    Toxicity of perfluorinated carboxylic acids with carbon chain C8 to C12 were tested with oligochaeta Tubifex tubifex. Toxicity was evaluated as the exposure time ET50 from onset of damage of the oligochaeta in saturated aqueous solutions. The ET50 fluctuated between 25 and 257 minutes. No statistically significant difference was found among the C8, C9 and C12 acids (ET50 between 143 and 257 minutes with large standard deviation). The acids with carbon chain C10 and C11 induced the effect sign...

  6. Photodissociation spectroscopy of the Mg+-acetic acid complex

    We have studied the structure and photodissociation of Mg+-acetic acid clusters. Ab initio calculations suggest four relatively strongly bound ground state isomers for the [MgC2H4O2]+ complex. These isomers include the cis and trans forms of the Mg+-acetic acid association complex with Mg+ bonded to the carbonyl O atom of acetic acid, the Mg+-acetic acid association complex with Mg+ bonded to the hydroxyl O atom of acetic acid, or to a Mg+-ethenediol association complex. Photodissociation through the Mg+-based 3p+, MgOH+, Mg(H2O)+, CH3CO+, and MgCH3+. At low energies the dominant reactive quenching pathway is through dehydration to Mg(H2O)+, but additional reaction channels involving C-H and C-C bond activation are also open at higher energies

  7. Analysis of aliphatic carboxylic acids in anaerobic digestion process waters by ion-exclusion chromatography

    Kazuaki ITO; Kazuhiko TANAKA; Jun SAKAMOTO; Kazuya NAGAOKA; Yohichi TAKAYAMA; Takashi KANAHORI; Hiroshi SUNAHARA; Tsuneo HAYASHI; Shinji SATO; Takeshi HIROKAWA

    2012-01-01

    The analysis of seven aliphatic carboxylic acids ( formic,acetic,propionic,iso-butyric,n-butyric,iso-valeric and n-valeric acid) in anaerobic digestion process waters for biogas production was examined by ion-exclusion chromatography with dilute acidic eluents (benzoic acid,perfluorobutyric acid (PFBA) and sulfuric acid) and non-suppressed conductivity/ultraviolet (UV) detection.The columns used were a styrene/divinylbenzene-based strongly acidic cation-exchange resin column ( TSKgel SCX) and a polymethacrylate-based weakly acidic cation-exchange resin column ( TSKgel Super IC-A/C ).Good separation was performed on the TSKgel SCX in shorter retention times.For the TSKgel Super IC-A/C,peak shape of the acids was sharp and symmetrical in spite of longer retention times.In addition,the mutual separation of the acids was good except for iso- and n-butyric acids.The better separation and good detection was achieved by using the two columns (TSKgel SCX and TSKgel Super IC-A/C connected in series),lower concentrations of PFBA and sulfuric acid as eluents,non-suppressed conductivity detection and UV detection at 210 nm.This analysis was applied to anaerobic digestion process waters.The chromatograms with conductivity detection were relatively simpler compared with those of UV detection.The use of two columns with different selectivities for the aliphatic carboxylic acids and the two detection modes was effective for the determination and identification of the analytes in anaerobic digestion process waters containing complex matrices.

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

    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. PMID:27191052

  9. Fermentation of lignocellulosic sugars to acetic acid by Moorella thermoacetica.

    Ehsanipour, Mandana; Suko, Azra Vajzovic; Bura, Renata

    2016-06-01

    A systematic study of bioconversion of lignocellulosic sugars to acetic acid by Moorella thermoacetica (strain ATCC 39073) was conducted. Four different water-soluble fractions (hydrolysates) obtained after steam pretreatment of lignocellulosic biomass were selected and fermented to acetic acid in batch fermentations. M. thermoacetica can effectively ferment xylose and glucose in hydrolysates from wheat straw, forest residues, switchgrass, and sugarcane straw to acetic acid. Xylose and glucose were completely utilized, with xylose being consumed first. M. thermoacetica consumed up to 62 % of arabinose, 49 % galactose and 66 % of mannose within 72 h of fermentation in the mixture of lignocellulosic sugars. The highest acetic acid yield was obtained from sugarcane straw hydrolysate, with 71 % of theoretical yield based on total sugars (17 g/L acetic acid from 24 g/L total sugars). The lowest acetic acid yield was observed in forest residues hydrolysate, with 39 % of theoretical yield based on total sugars (18 g/L acetic acid from 49 g/L total sugars). Process derived compounds from steam explosion pretreatment, including 5-hydroxymethylfurfural (0.4 g/L), furfural (0.1 g/L) and total phenolics (3 g/L), did not inhibit microbial growth and acetic acid production yield. This research identified two major factors that adversely affected acetic acid yield in all hydrolysates, especially in forest residues: (i) glucose to xylose ratio and (ii) incomplete consumption of arabinose, galactose and mannose. For efficient bioconversion of lignocellulosic sugars to acetic acid, it is imperative to have an appropriate balance of sugars in a hydrolysate. Hence, the choice of lignocellulosic biomass and steam pretreatment design are fundamental steps for the industrial application of this process. PMID:26992903

  10. Biarylalkyl Carboxylic Acid Derivatives as Novel Antischistosomal Agents.

    Mäder, Patrick; Blohm, Ariane S; Quack, Thomas; Lange-Grünweller, Kerstin; Grünweller, Arnold; Hartmann, Roland K; Grevelding, Christoph G; Schlitzer, Martin

    2016-07-01

    Parasitic platyhelminths are responsible for serious infectious diseases, such as schistosomiasis, which affect humans as well as animals across vast regions of the world. The drug arsenal available for the treatment of these diseases is limited; for example, praziquantel is the only drug currently used to treat ≥240 million people each year infected with Schistosoma spp., and there is justified concern about the emergence of drug resistance. In this study, we screened biarylalkyl carboxylic acid derivatives for their antischistosomal activity against S. mansoni. These compounds showed significant influence on egg production, pairing stability, and vitality. Tegumental lesions or gut dilatation was also observed. Substitution of the terminal phenyl residue in the biaryl scaffold with a 3-hydroxy moiety and derivatization of the terminal carboxylic acid scaffold with carboxamides yielded compounds that displayed significant antischistosomal activity at concentrations as low as 10 μm with satisfying cytotoxicity values. The present study provides detailed insight into the structure-activity relationships of biarylalkyl carboxylic acid derivatives and thereby paves the way for a new drug-hit moiety for fighting schistosomiasis. PMID:27159334

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

    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, N2 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

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

    Bahrami, Zohreh; Badiei, Alireza, E-mail: abadiei@khayam.ut.ac.ir [University of Tehran, School of Chemistry, College of Science (Iran, Islamic Republic of); Ziarani, Ghodsi Mohammadi [Alzahra University, Research Laboratory of Pharmaceutical (Iran, Islamic Republic of)

    2015-03-15

    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{sub 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.

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

    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. PMID:26898679

  14. Measurement of the rates of oxindole-3-acetic acid turnover, and indole-3-acetic acid oxidation in Zea mays seedlings

    Nonhebel, H. M.; Bandurski, R. S. (Principal Investigator)

    1986-01-01

    Oxindole-3-acetic acid is the principal catabolite of indole-3-acetic acid in Zea mays seedlings. In this paper measurements of the turnover of oxindole-3-acetic acid are presented and used to calculate the rate of indole-3-acetic acid oxidation. [3H]Oxindole-3-acetic acid was applied to the endosperm of Zea mays seedlings and allowed to equilibrate for 24 h before the start of the experiment. The subsequent decrease in its specific activity was used to calculate the turnover rate. The average half-life of oxindole-3-acetic acid in the shoots was found to be 30 h while that in the kernels had an average half-life of 35h. Using previously published values of the pool sizes of oxindole-3-acetic acid in shoots and kernels from seedlings of the same age and variety, and grown under the same conditions, the rate of indole-3-acetic acid oxidation was calculated to be 1.1 pmol plant-1 h-1 in the shoots and 7.1 pmol plant-1 h-1 in the kernels.

  15. Adsorption of acetic acid on different carbons

    K. Ouattara

    2012-10-01

    Full Text Available This study presents a double environmental aspect, on one hand, decline of the cost of the waste water treatment thanks to a cheap adsorbing, on the other hand, the valuation of coconut shells.The acetic acid was used as adsorbent because the knowledge of the size of its molecule (21 Å2 allows characterizing studied carbons.The model of Langmuir describes well the isotherms of adsorption on the various types of studied carbons. It stands out in this study that the capacity of adsorption of inactivated carbon grain (CNAG COCO doubles practically if this one is reduced in powder. Besides, the inactivated carbon powder (CNAP COCO and the activated carbon grain (CAG COCO have the same capacity of adsorption. So, the specific surfaces of the CNAP COCO and CAG COCO are identical: SL = 77 m2/g while that of the CNAG is only 32 m2/g. The use of inactivated carbon powder can be thus recommended to treat waste water opposite the inactivated grain carbon which isn’t of real interest.

  16. Kinetics and Mechanism of Oxidation of Phenyl Acetic Acid and Dl-Mandelic Acid by Permanganate in Acid Medium

    B. Syama Sundar; P.S.Radhakrishna murti

    2014-01-01

    Kinetics of oxidation of phenyl acetic acid and DL- Mandelic acid by potassium permanganate in aqueous acetic acid and perchloric acid mixture reveals that the kinetic orders are first order in oxidant, first order in H+ and zero order in substrate for phenyl acetic acid. DL-Mandelic acid exhibits first order in oxidant and zero order in substrate. The results are rationalised by a mechanism involving intermediate formation of mandelic acid in case of Phenyl acetic acid and ester formation wi...

  17. Oxidation of indole-3-acetic acid and oxindole-3-acetic acid to 2,3-dihydro-7-hydroxy-2-oxo-1H indole-3-acetic acid-7'-O-beta-D-glucopyranoside in Zea mays seedlings

    Nonhebel, H. M.; Bandurski, R. S.

    1984-01-01

    Radiolabeled oxindole-3-acetic acid was metabolized by roots, shoots, and caryopses of dark grown Zea mays seedlings to 2,3-dihydro-7-hydroxy-2-oxo-1H indole-3-acetic acid-7'-O-beta-D-glycopyranoside with the simpler name of 7-hydroxyoxindole-3-acetic acid-glucoside. This compound was also formed from labeled indole-3-acetic acid supplied to intact seedlings and root segments. The glucoside of 7-hydroxyoxindole-3-acetic acid was also isolated as an endogenous compound in the caryopses and shoots of 4-day-old seedlings. It accumulates to a level of 4.8 nanomoles per plant in the kernel, more than 10 times the amount of oxindole-3-acetic acid. In the shoot it is present at levels comparable to that of oxindole-3-acetic acid and indole-3-acetic acid (62 picomoles per shoot). We conclude that 7-hydroxyoxindole-3-acetic acid-glucoside is a natural metabolite of indole-3-acetic acid in Z. mays seedlings. From the data presented in this paper and in previous work, we propose the following route as the principal catabolic pathway for indole-3-acetic acid in Zea seedlings: Indole-3-acetic acid --> Oxindole-3-acetic acid --> 7-Hydroxyoxindole-3-acetic acid --> 7-Hydroxyoxindole-3-acetic acid-glucoside.

  18. Solubilities of Isophthalic Acid in Acetic Acid + Water Solvent Mixtures

    CHENG Youwei; HUO Lei; LI Xi

    2013-01-01

    The solubilities of isophthalic acid (1) in binary acetic acid (2) + water (3) solvent mixtures were determined in a pressurized vessel.The temperature range was from 373.2 to 473.2K and the range of the mole fraction of acetic acid in the solvent mixtures was from x2 =0 to 1.A new method to measure the solubility was developed,which solved the problem of sampling at high temperature.The experimental results indicated that within the temperature range studied,the solubilities of isophthalic acid in all mixtures showed an increasing trend with increasing temperature.The experimental solubilities were correlated by the Buchowski equation,and the calculate results showed good agreement with the experimental solubilities.Furthermore,the mixed solvent systems were found to exhibit a maximum solubility effect on the solubility,which may be attributed to the intermolecular association between the solute and the solvent mixture.The maximum solubility effect was well modeled by the modified Wilson equation.

  19. Determination of some aliphatic carboxylic acids in anaerobic digestion process waters by ion-exclusion chromatography with conductimetric detection on a weakly acidic cation-exchange resin column.

    Ito, Kazuaki; Takayama, Yohichi; Ikedo, Mikaru; Mori, Masanobu; Taoda, Hiroshi; Xu, Qun; Hu, Wenzhi; Sunahara, Hiroshi; Hayashi, Tsuneo; Sato, Shinji; Hirokawa, Takeshi; Tanaka, Kazuhiko

    2004-06-11

    The determination of seven aliphatic carboxylic acids, formic, acetic, propionic, isobutyric, n-butyric, isovaleric and n-valeric acids in anaerobic digestion process waters was examined using ion-exclusion chromatography with conductimetric detection. The analysis of these biologically important carboxylic acids is necessary as a measure for evaluating and controlling the process. The ion-exclusion chromatography system employed consisted of polymethacrylate-based weakly acidic cation-exchange resin columns (TSKgel OApak-A or TSKgel Super IC-A/C). weakly acidic eluent (benzoic acid), and conductimetric detection. Particle size and cation-exchange capacity were 5 microm and 0.1 meq./ml for TSKgel OApak-A and 3 microm and 0.2 meq./ml for TSKgel Super IC-A/C, respectively. A dilute eluent (1.0-2.0 mM) of benzoic acid was effective for the high resolution and highly conductimetric detection of the carboxylic acids. The good separation of isobutyric and n-butyric acids was performed using the TSKgel Super IC-A/C column (150 mm x 6.0 mm i.d. x 2). The simple and good chromatograms were obtained by the optimized ion-exclusion chromatography conditions for real samples from mesophilic anaerobic digestors, thus the aliphatic carboxylic acids were successfully determined without any interferences. PMID:15250416

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

    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 to...... undergo initial diazotization and successive hydroxylation, since neither β-amino acids nor acid derivatives such as esters and amides undergo hydroxylations. The method is successfully applied for the synthesis of 18 proteinogenic amino acids. © 2014 Elsevier Ltd. All rights reserved....

  1. Probiotic and Acetic Acid Effect on Broiler Chickens Performance

    Martin Král; Mária Angelovičová; Ľubica Mrázová; Jana Tkáčová; Martin Kliment

    2011-01-01

    Probiotics and organic acids are widely accepted as an alternative to in-feed antibiotics in poultry production. We carried the experiment with broiler chickens. In experiment we research effect of probiotic and acetic acids on the performance of broiler chickens. A total number of 200 one day old broiler chickens were distributed to two dietary groups. Broiler chickens in control group were fed with standard feed mixture and experimental group 1% vinegar contained 5% acetic acid used in drin...

  2. Protection of historical lead against acetic acid vapour

    Pecenová Z.; Kouřil M.

    2016-01-01

    Historical lead artefacts (small figurines, appliques, bull (metal seal) can be stored in depository and archives in inconvenient storage conditions. The wooden show-case or paper packagings release volatile organic compound to the air during their degradation. These acids, mainly acetic acid are very corrosive for lead. The thin layer of corrosion products which slows atmospheric corrosion is formed on lead surface in atmospheric condition. In presence of acetic acid vapour the voluminous co...

  3. Uranyl complexes of n-alkanediaminotetra-acetic acids

    The uranyl complexes of n-propanediaminetetra-acetic acid, n-butanediaminetetra-acetic acid and n-hexanediaminetetra-acetic acid have been studied by potentiometry, with computer evaluation of the titration data by the MINIQUAD program. Stability constants of the 1:1 and 2:1 metal:ligand chelates have been determined as well as the respective hydrolysis and polymerization constants at 25 deg in 0.10M and 1.00M KNO3. The influence of the length of the alkane chain of the ligands on the complexes formed is discussed. (author)

  4. Biosynthetic origin of acetic acid using SNIF-NMR

    The main purpose of this work is to describe the use of the technique Site-Specific Natural Isotopic Fractionation of hydrogen (SNIF-NMR), using 2H and 1H NMR spectroscopy, to investigate the biosynthetic origin of acetic acid in commercial samples of Brazilian vinegar. This method is based on the deuterium to hydrogen ratio at a specific position (methyl group) of acetic acid obtained by fermentation, through different biosynthetic mechanisms, which result in different isotopic ratios. We measured the isotopic ratio of vinegars obtained through C3, C4, and CAM biosynthetic mechanisms, blends of C3 and C4 (agrins) and synthetic acetic acid. (author)

  5. Biosynthesis of the halogenated auxin, 4-chloroindole-3-acetic acid.

    Tivendale, Nathan D; Davidson, Sandra E; Davies, Noel W; Smith, Jason A; Dalmais, Marion; Bendahmane, Abdelhafid I; Quittenden, Laura J; Sutton, Lily; Bala, Raj K; Le Signor, Christine; Thompson, Richard; Horne, James; Reid, James B; Ross, John J

    2012-07-01

    Seeds of several agriculturally important legumes are rich sources of the only halogenated plant hormone, 4-chloroindole-3-acetic acid. However, the biosynthesis of this auxin is poorly understood. Here, we show that in pea (Pisum sativum) seeds, 4-chloroindole-3-acetic acid is synthesized via the novel intermediate 4-chloroindole-3-pyruvic acid, which is produced from 4-chlorotryptophan by two aminotransferases, TRYPTOPHAN AMINOTRANSFERASE RELATED1 and TRYPTOPHAN AMINOTRANSFERASE RELATED2. We characterize a tar2 mutant, obtained by Targeting Induced Local Lesions in Genomes, the seeds of which contain dramatically reduced 4-chloroindole-3-acetic acid levels as they mature. We also show that the widespread auxin, indole-3-acetic acid, is synthesized by a parallel pathway in pea. PMID:22573801

  6. Determination of the thermodynamic quantities of complexation between Eu(III) and carboxylic acids by microcalorimetry

    Potentiometric and microcalorimetric titration techniques were applied to determine the Gibbs free energies and enthalpies of the protonation of some carboxylic acids (acetic, glycolic, malonic and malic acids) and their complexation with Eu(III) in 1.0 M NaClO4 solution at 25 C, where Eu(III) was used as a chemical analogue of radiologically important Am(III). By using the values of ΔG determined by potentiometric titrations, the results of calorimetric titrations were analyzed to give the values of ΔH and ΔS. To support the discussion on the obtained thermodynamic quantities, the hydration numbers of Eu(III) in the complexes were obtained by TRLFS measurement, where the luminescence lifetime of Eu(III) excited by 394 nm laser was measured. A few to several kJ/mol of enthalpies were determined for the reactions within the uncertainties of ±0.01 to ±0.4. These enthalpy values indicated that the protonation of these carboxylates were entropy-driven, that is, vertical stroke - TΔS vertical stroke >> vertical stroke ΔH vertical stroke in ΔG = ΔH - TΔS. The complexations of Eu(III) were also shown to be controlled mainly by entropy term. The results of TRLFS measurement revealed that the number of dehydrated water molecule increased with the degree of complexation. A linear relation was found between total entropy change of the system (ΔST) and the net number of released molecules from the central Eu(III) ion. However, the values of ΔST for the hydroxy-carboxylates were smaller than that for simple carboxylates at the same net number of molecules released from Eu(III), suggesting that the dehydration occurred not only in the cation but also in the anion. (orig.)

  7. Acetic acid assisted cobalt methanesulfonate catalysed chemoselective diacetylation of aldehydes

    Min Wang; Zhi Guo Song; Hong Gong; Heng Jiang

    2008-01-01

    Cobalt methanesulfonate in combination with acetic acid catalysed the chemoselective diacetylation of aldehyde with acetic anhydride at room temperature under solvent free conditions. After reaction, cobalt methanesulfonate can be easily recovered and mused many times. The reaction was mild and efficient with good to high yields.

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

    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.

  9. Ototoxicity of acetic acid on the guinea pig cochlea

    Yamano, Takafumi; Higuchi, Hitomi; Nakagawa, Takashi; Morizono, Tetsuo

    2015-01-01

    Background To evaluate the ototoxicity of acetic acid solutions. Methods Compound action potentials (CAPs) of the eighth nerve were measured in guinea pigs before and after the application of acetic acid in the middle ear cavity. The pH values of the acetic acid solutions were pH 3.0, 4.0, and 5.0, and the application times were 30 min, 24 h, and 1 week. Results Acetic acid solution (pH 3.0, N = 3) for 30 min caused no significant elevation in CAP threshold at 4 kHz, but a significant elevati...

  10. A NOVEL COPOLYMER-BOUND CIS- DICARBONYLRHODIUM COMPLEX FOR THE CARBONYLATION OF METHANOL TO ACETIC ACID AND ACETIC ANHYDRIDE

    YUAN Guoqing; CHEN Yuying; CHEN Rongyao

    1989-01-01

    A series of porous microspheres of linear and ethylene diacrylate (M ') cross-linked copolymers of 2 - vinylpyridine (V) and methyl acrylate (M) reacted with tetracarbonyldichlorodirhodium to form a series of cis-dicarbonylrhodium chelate complex (MVRh and MVM 'Rh). They are thermally stable yet very reactive in the carbonylation of methanol to acetic acid, and of methanol - acetic acid mixture to acetic acid and acetic anhydride with a selectivity of 100% under relatively mild and anhydrous conditions.

  11. Electrochemical properties of polyethylene membrane modified with carboxylic acid group

    Two cation-exchange membranes modified with the carboxylic acid group for battery separator were prepared by radiation-induced grafting of acrylic acid (AA) and methacrylic acid (MA) onto a polyethylene (PE) film. The surface area, thickness, volume, water uptake, ion-exchange capacity, specific electric resistance, and electrolyte flux were evaluated after PE film was grafted with AA and MA. It was found that KOH diffusion flux of AA-grafted PE membrane and MA-grafted PE membrane increased with an increase in the degree of grafting. AA-grafted PE membrane had a higher diffusion flux than MA-grafted PE membrane. Electrical resistance of two cation-exchange membranes modified with AA and MA decreased rapidly with an increase in the degree of grafting. (author)

  12. Effect of Concentration of Structurally-Different Carboxylic Acids on Growth and Aggregation of Calcium Oxalate in Gel Systems

    DENG,Sui-Ping; OUYANG,Jian-Ming

    2007-01-01

    The effect of concentration of structurally-different carboxylic acids such as ethylene diamine tetraacetic acid (H4edta), citric acid (H3cit), tartaric acid (H2tart), and acetic acid (HOAc) on growth and aggregation of calcium oxalate (CaOxa) in gel systems was comparatively investigated. H2tart and H3cit could change the morphology of calcium oxalate monohydrate (COM) and induce the formation of calcium oxalate dihydrate (COD). H4edta could induce the formation of COD at a lower concentration of 0.33 mmol/L and have the strongest ability to inhibit aggregation of COM. HOAc inhibited COM aggregation only at a higher concentration than 500 mmol/L. With increasing the number of carboxylic groups in an acid or increasing the concentration of carboxylic acid, the capacity of this acid to induce COD formation and to inhibit growth and aggregation of COM crystals increased. That is, this capacity followed the order: H4edta>H3cit>H2tart>>HOAc. The result in this work suggested that the presence of H3cit and H2tart in urine played a role in the natural defense against stone formation.

  13. Genetic dissection of acetic acid tolerance in Saccharomyces cerevisiae.

    Geng, Peng; Xiao, Yin; Hu, Yun; Sun, Haiye; Xue, Wei; Zhang, Liang; Shi, Gui-Yang

    2016-09-01

    Dissection of the hereditary architecture underlying Saccharomyces cerevisiae tolerance to acetic acid is essential for ethanol fermentation. In this work, a genomics approach was used to dissect hereditary variations in acetic acid tolerance between two phenotypically different strains. A total of 160 segregants derived from these two strains were obtained. Phenotypic analysis indicated that the acetic acid tolerance displayed a normal distribution in these segregants, and suggested that the acetic acid tolerant traits were controlled by multiple quantitative trait loci (QTLs). Thus, 220 SSR markers covering the whole genome were used to detect QTLs of acetic acid tolerant traits. As a result, three QTLs were located on chromosomes 9, 12, and 16, respectively, which explained 38.8-65.9 % of the range of phenotypic variation. Furthermore, twelve genes of the candidates fell into the three QTL regions by integrating the QTL analysis with candidates of acetic acid tolerant genes. These results provided a novel avenue to obtain more robust strains. PMID:27430512

  14. Evaluation of toxic effects of several carboxylic acids on bacterial growth by toxicodynamic modelling

    Vázquez José

    2011-11-01

    Full Text Available Abstract Background Effects of organic acids on microbial fermentation are commonly tested in investigations about metabolic behaviour of bacteria. However, they typically provide only descriptive information without modelling the influence of acid concentrations on bacterial kinetics. Results We developed and applied a mathematical model (secondary model to capture the toxicological effects of those chemicals on kinetic parameters that define the growth of bacteria in batch cultures. Thus, dose-response kinetics were performed with different bacteria (Leuconostoc mesenteroides, Carnobacterium pisicola, Escherichia coli, Bacillus subtilis and Listonella anguillarum exposed at increasing concentrations of individual carboxylic acids (formic, acetic, propionic, butyric and lactic. In all bioassays the acids affected the maximum bacterial load (Xm and the maximum growth rate (vm but only in specific cases the lag phase (λ was modified. Significance of the parameters was always high and in all fermentations the toxicodynamic equation was statistically consistent and had good predictability. The differences between D and L-lactic acid effects were significant for the growth of E. coli, L. mesenteroides and C. piscicola. In addition, a global parameter (EC50,τ was used to compare toxic effects and provided a realistic characterization of antimicrobial agents using a single value. Conclusions The effect of several organic acids on the growth of different bacteria was accurately studied and perfectly characterized by a bivariate equation which combines the basis of dose-response theory with microbial growth kinetics (secondary model. The toxicity of carboxylic acids was lower with the increase of the molecular weight of these chemicals.

  15. Removal of dicyclohexyl acetic acid from aqueous solution using ultrasound, ozone and their combination.

    Kumar, Pardeep; Headley, John; Peru, Kerry; Bailey, Jon; Dalai, Ajay

    2014-01-01

    Naphthenic acids are a complex mixture of organic components, some of which include saturated alkyl-substituted cycloaliphatic carboxylic acids and acyclic aliphatic acids. They are naturally found in hydrocarbon deposits like oil sand, petroleum, bitumen and crude oil. In this study, the oxidation of a relatively high molecular weight naphthenic acid (Dicyclohexyl acetic acid) was investigated using ozonation, ultrasonication and hydrogen peroxide alone and their combinations. Effects on oxidation of dicyclohexyl acetic acid (DAA) were measured for different concentrations of ozone ranging between 0.7 to 3.3 mg L(-1) and pH in the range 6 to 10. Ultrasonication and hydrogen peroxide alone were not effective to oxidize dicyclohexyl acetic acid, but combining ultrasonication with H2O2 had a significant effect on oxidation of dicyclohexyl acetic acid with maximum removal reaching to 84 ± 2.2% with 81 ± 2.1% reduction in chemical oxygen demand (COD). Synergistic effects were observed for combining ultrasonication with ozonation and resulted in 100% DAA removal with 98 ± 0.8% reduction in COD within 15 min at 3.3 mg L(-1) ozone concentration and 130 Watts ultrasonication power. The reaction conditions obtained for the maximum oxidation of DAA and COD removal were used for the degradation of naphthenic acids mixture extracted from oil sands process water (OSPW). The percentage oxidation of NAs mixture extracted from OSPW was 89.3 ± 1.1% in ozonation and combined ozonation and ultrasonication, but COD removal observed was 65 ± 1.2% and 78 ± 1.4% for ozonation and combined ozonation and ultrasonication treatments, respectively. PMID:25137539

  16. Integrated process for preparing a carboxylic acid from an alkane

    Benderly, Abraham (Elkins Park, PA); Chadda, Nitin (Radnor, PA); Sevon, Douglass (Fairless Hills, PA)

    2011-12-20

    The present invention relates to an integrated process for producing unsaturated carboxylic acids from the corresponding C.sub.2-C.sub.4 alkane. The process begins with performance of thermally integrated dehydrogenation reactions which convert a C.sub.2-C.sub.4 alkane to its corresponding C.sub.2-C.sub.4 alkene, and which involve exothermically converting a portion of an alkane to its corresponding alkene by oxidative dehydrogenation in an exothermic reaction zone, in the presence of oxygen and a suitable catalyst, and then feeding the products of the exothermic reaction zone to an endothermic reaction zone wherein at least a portion of the remaining unconverted alkane is endothermically dehydrogenated to form an additional quantity of the same corresponding alkene, in the presence of carbon dioxide and an other suitable catalyst. The alkene products of the thermally integrated dehydrogenation reactions are then provided to a catalytic vapor phase partial oxidation process for conversion of the alkene to the corresponding unsaturated carboxylic acid or nitrile. Unreacted alkene and carbon dioxide are recovered from the oxidation product stream and recycled back to the thermally integrated dehydrogenation reactions.

  17. Exploring the reductive capacity of Pyrococcus furiosus. The reduction of carboxylic acids and pyridine nucleotides

    Ban, van den, A.W.

    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 acids.Reductions of carboxylic acids are interesting reactions, since the generated products, aldehydes and alcohols, are potentially applicable in the fine-chemical industry. However, the reduction of carboxylic acids to the corresponding aldehydes is a thermodynamicall...

  18. Tetrazole acetic acid: Tautomers, conformers, and isomerization

    Araujo-Andrade, C. [Unidad Académica de Física de la Universidad Autónoma de Zacatecas, Zacatecas (Mexico); Department of Chemistry, University of Coimbra, 3004-535 Coimbra (Portugal); Reva, I., E-mail: reva@qui.uc.pt; Fausto, R. [Department of Chemistry, University of Coimbra, 3004-535 Coimbra (Portugal)

    2014-02-14

    Monomers of (tetrazol-5-yl)-acetic acid (TAA) were obtained by sublimation of the crystalline compound and the resulting vapors were isolated in cryogenic nitrogen matrices at 13 K. The conformational and tautomeric composition of TAA in the matrix was characterized by infrared spectroscopy and vibrational calculations carried out at the B3LYP/6-311++G(d,p) level. TAA may adopt two tautomeric modifications, 1H- and 2H-, depending on the position of the annular hydrogen atom. Two-dimensional potential energy surfaces (PESs) of TAA were theoretically calculated at the MP2/6-311++G(d,p) level, for each tautomer. Four and six symmetry-unique minima were located on these PESs, for 1H- and 2H-TAA, respectively. The energetics of the detected minima was subsequently refined by calculations at the QCISD level. Two 1H- and three 2H-conformers fall within the 0–8 kJ mol{sup −1} energy range and should be appreciably populated at the sublimation temperature (∼330 K). Observation of only one conformer for each tautomer (1ccc and 2pcc) is explained in terms of calculated barriers to conformational rearrangements. All conformers with the cis O=COH moiety are separated by low barriers (less than 10 kJ mol{sup −1}) and collapse to the most stable 1ccc (1H-) and 2pcc (2H-) forms during deposition of the matrix. On the trans O=COH surfaces, the relative energies are very high (between 12 and 27 kJ mol{sup −1}). The trans forms are not thermally populated at the sublimation conditions and were not detected in matrices. One high-energy form in each tautomer, 1cct (1H-) and 2pct (2H-), was found to differ from the most stable form only by rotation of the OH group and separated from other forms by high barriers. This opened a perspective for their stabilization in a matrix. 1cct and 2pct were generated in the matrices selectively by means of narrow-band near-infrared (NIR) irradiations of the samples at 6920 and 6937 cm{sup −1}, where the first OH stretching overtone

  19. Tetrazole acetic acid: Tautomers, conformers, and isomerization

    Monomers of (tetrazol-5-yl)-acetic acid (TAA) were obtained by sublimation of the crystalline compound and the resulting vapors were isolated in cryogenic nitrogen matrices at 13 K. The conformational and tautomeric composition of TAA in the matrix was characterized by infrared spectroscopy and vibrational calculations carried out at the B3LYP/6-311++G(d,p) level. TAA may adopt two tautomeric modifications, 1H- and 2H-, depending on the position of the annular hydrogen atom. Two-dimensional potential energy surfaces (PESs) of TAA were theoretically calculated at the MP2/6-311++G(d,p) level, for each tautomer. Four and six symmetry-unique minima were located on these PESs, for 1H- and 2H-TAA, respectively. The energetics of the detected minima was subsequently refined by calculations at the QCISD level. Two 1H- and three 2H-conformers fall within the 0–8 kJ mol−1 energy range and should be appreciably populated at the sublimation temperature (∼330 K). Observation of only one conformer for each tautomer (1ccc and 2pcc) is explained in terms of calculated barriers to conformational rearrangements. All conformers with the cis O=COH moiety are separated by low barriers (less than 10 kJ mol−1) and collapse to the most stable 1ccc (1H-) and 2pcc (2H-) forms during deposition of the matrix. On the trans O=COH surfaces, the relative energies are very high (between 12 and 27 kJ mol−1). The trans forms are not thermally populated at the sublimation conditions and were not detected in matrices. One high-energy form in each tautomer, 1cct (1H-) and 2pct (2H-), was found to differ from the most stable form only by rotation of the OH group and separated from other forms by high barriers. This opened a perspective for their stabilization in a matrix. 1cct and 2pct were generated in the matrices selectively by means of narrow-band near-infrared (NIR) irradiations of the samples at 6920 and 6937 cm−1, where the first OH stretching overtone vibrations of 1ccc and 2pcc

  20. Ion-exclusion chromatographic separations of C1-C6 aliphatic carboxylic acids on a sulfonated styrene-divinylbenzene co-polymer resin column with 5-methylhexanoic acid as eluent.

    Ohta, Kazutoku; Towata, Atsuya; Ohashi, Masayoshi

    2003-05-16

    The application of C7 aliphatic carboxylic acids (heptanoic, 2-methylhexanoic, 5-methylhexanoic and 2,2-dimethyl-n-valeric acids) as eluents in ion-exclusion chromatography with conductimetric detection for C1-C6 aliphatic carboxylic acids (formic, acetic, propionic, isobutyric, butyric, isovaleric, valeric, isocaproic and caproic acids) was carried out using a highly sulfonated styrene-divinylbenzene co-polymer resin (TSKgel SCX) in the H+ form as a stationary phase. When using 0.05 mM sulfuric acid at pH 4.0 as the eluent, peak shapes of hydrophobic carboxylic acids (isovaleric, valeric, isocaproic and caproic acids) were tailed strongly. In contrast, when using 1 mM these C7 carboxylic acids at pH ca. 4 as the eluents, although system peaks (vacant peaks) corresponding to these C7 carboxylic acids appeared, peak shapes of these hydrophobic acids were improved drastically. Excellent simultaneous separation and relatively high sensitive conductimetric detection for these C1-C6 aliphatic carboxylic acids were achieved in 25 min on the TSKgel SCX column (150 x 6 mm I.D.) using 1 mM 5-methylhexanoic acid at pH 4.0 as the eluent. PMID:12830882

  1. Additive effects of acetic acid upon hydrothermal reaction of amylopectin

    It is well known that over 0.8 kg kg−1 of starch is consisted of amylopectin (AP). In this study, production of glucose for raw material of ethanol by hydrothermal reaction of AP as one of the model compound of food is discussed. Further, additive effects of acetic acid upon hydrothermal reactions of AP are also investigated. During hydrothermal reaction of AP, production of glucose occurred above 453 K, and the glucose yield increased to 0.48 kg kg−1 at 473 K. Upon hydrothermal reaction of AP at 473 K, prolongation of the holding time was not effective for the increase of the glucose yield. Upon hydrothermal reaction of AP at 473 K for 0 s, the glucose yield increased significantly by addition between 0.26 mol L−1 and 0.52 mol L−1 of acetic acid. However, the glucose yield decreased and the yield of the other constituents increased with the increases of concentration of acetic acid from 0.65 mol L−1 to 3.33 mol L−1. It was considered that hydrolysis of AP to yield glucose was enhanced due to the increase of the amount of proton derived from acetic acid during hydrothermal reaction with 0.52 mol L−1 of acetic acid. -- Highlights: ► Glucose production by hydrothermal reaction of amylopectin (AP) at 473 K. ► Glucose yield increased to 0.48 kg kg-1 at 473 K. ► Prolongation of holding time was not effective for glucose yield. ► Glucose yield increased significantly by acetic acid (0.26–0.52 mol L-1) addition. ► Hydrolysis of AP to glucose was enhanced due to increase of proton from acetic acid.

  2. Structure–anticancer activity relationships among 4-azolidinone-3-carboxylic acids derivatives

    Lesyk R. B.

    2010-04-01

    Full Text Available The aim of present research was investigation of anticancer activity of 4-azolidinone-3-carboxylic acids derivatives, and studies of structure–activity relationships (SAR aspects. Methods. Organic synthesis; spectral methods; anticancer screening was performed according to the US NCI protocol (Developmental Therapeutic Program. Results. The data of new 4-thiazolidinone-3-alkanecarboxylic acids derivatives in vitro anticancer activity were described. The most active compounds which belong to 5-arylidene-2,4- thia(imidazolidinone-3-alkanecarboxylic acids; 5-aryl(heterylidenerhodanine-3-succinic acids derivatives were selected. Determination of some SAR aspects which allowed to determine directions in lead- compounds structure optimization, as well as desirable molecular fragments for design of potential anticancer agents based on 4-azolidinone scaffold were performed. 5-Arylidenehydantoin-3-acetic acids amides were identified as a new class of significant selective antileukemic agents. Possible pharmacophore scaffold of 5-ylidenerhodanine-3-succinic acids derivatives was suggested. Conclusions. The series of active compounds with high anticancer activity and/or selectivity levels were selected. Some SAR aspects were determined and structure design directions were proposed.

  3. Biogeochemistry of the stable carbon isotopes in carboxylic acids

    The carbon isotopic compositions of the carboxyl carbons of fatty acids were determined by measuring the isotopic composition of the carbon dioxide quantitatively released from the acid. A modified version of the Schmidt decarboxylation developed and tested in this work was employed. A study of the evolution of CO2 at 5 +- 20C from the Schmidt decarboxylation of octanoic acid during the developmental program revealed two kinetic phases, each characterized by different rate constants and carbon isotope effects. The first, slower reaction phase displayed overall first-order kinetics, its rate being independent of HN3 concentration. Both pre-equilibration of the HN3-CHCl3 decarboxylation reagent with H2SO4 and saturation of the catalytic H2SO4 phase with KHSO4 drastically altered the rate of evolution and isotopic composition of the product CO2. The mechanistic implications of these results were discussed. A review of the metabolism of saturated fatty acids was made in which the impact of potential isotope fractionations in the various chemical reactions comprising the biosynthetic pathways on the intramolecular carbon isotope distribution within fatty acids was discussed

  4. Kinetics and Mechanism of Oxidation of Phenyl Acetic Acid and Dl-Mandelic Acid by Permanganate in Acid Medium

    B.Syama Sundar

    2014-06-01

    Full Text Available Kinetics of oxidation of phenyl acetic acid and DL- Mandelic acid by potassium permanganate in aqueous acetic acid and perchloric acid mixture reveals that the kinetic orders are first order in oxidant, first order in H+ and zero order in substrate for phenyl acetic acid. DL-Mandelic acid exhibits first order in oxidant and zero order in substrate. The results are rationalised by a mechanism involving intermediate formation of mandelic acid in case of Phenyl acetic acid and ester formation with Mn (VII in case of DL-Mandelic acid. The following order of reactivity is observed: DL-Mandelic acid > Phenyl acetic acid. The high reactivity of DL-Mandelic acid over phenyl acetic acid may be due to different mechanisms operating with the two substrates and benzaldehyde is the final product in both the cases.

  5. Acetic acid removal from corn stover hydrolysate using ethyl acetate and the impact on Saccharomyces cerevisiae bioethanol fermentation.

    Aghazadeh, Mahdieh; Ladisch, Michael R; Engelberth, Abigail S

    2016-07-01

    Acetic acid is introduced into cellulose conversion processes as a consequence of composition of lignocellulose feedstocks, causing significant inhibition of adapted, genetically modified and wild-type S. cerevisiae in bioethanol fermentation. While adaptation or modification of yeast may reduce inhibition, the most effective approach is to remove the acetic acid prior to fermentation. This work addresses liquid-liquid extraction of acetic acid from biomass hydrolysate through a pathway that mitigates acetic acid inhibition while avoiding the negative effects of the extractant, which itself may exhibit inhibition. Candidate solvents were selected using simulation results from Aspen Plus™, based on their ability to extract acetic acid which was confirmed by experimentation. All solvents showed varying degrees of toxicity toward yeast, but the relative volatility of ethyl acetate enabled its use as simple vacuum evaporation could reduce small concentrations of aqueous ethyl acetate to minimally inhibitory levels. The toxicity threshold of ethyl acetate, in the presence of acetic acid, was found to be 10 g L(-1) . The fermentation was enhanced by extracting 90% of the acetic acid using ethyl acetate, followed by vacuum evaporation to remove 88% removal of residual ethyl acetate along with 10% of the broth. NRRL Y-1546 yeast was used to demonstrate a 13% increase in concentration, 14% in ethanol specific production rate, and 11% ethanol yield. This study demonstrated that extraction of acetic acid with ethyl acetate followed by evaporative removal of ethyl acetate from the raffinate phase has potential to significantly enhance ethanol fermentation in a corn stover bioethanol facility. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:929-937, 2016. PMID:27090191

  6. Spectrofluorimetric determination of gallium with calon-carboxylic acid

    2003-01-01

    A simple and sensitive spectrofluorimetric procedure for the analysis of microquantities of gallium in alloy wasdescribed. The method is based on the formation of Ga(Ⅲ)-CCA (calon-carboxylic acid) complex. The emission of thefluorescent complex was measured at λ = 620 nm with excitation at λ = 584 nm. A good linearity was found in the galliumrange of 0.7-280 ng/mL. The precision of the method is good and the relative standard deviation is 1.9% for a gallium stan-dard solution of 70 ng/mL. The procedure was proved to be suitable in terms of accuracy and selectivity for the mi-croamount of gallium in alloy.

  7. A synthetic approach to carbon-14 labeled anti-bacterial naphthyridine and quinolone carboxylic acids

    Ekhato, I.V.; Huang, C.C. (Parke, Davis and Co., Ann Arbor, MI (United States))

    1993-09-01

    Labeled versions of (S)-clinafloxacin (1) and two napththyridine carboxylic acid anti-bacterial compounds 2 and 3 which are currently in development were synthesized. Preparations started from hitherto unknown bromo compounds 22 and 10, from which the corresponding [sup 14]C-labeled aromatic carboxylic acids 23 and 12 were generated by metal-halogen exchange followed by carboxylation reaction. Details of these preparations are given. (author).

  8. "Protective Effects of Some Azo Derivatives of 5-aminosalicylic Acid and Their Pegylated Prodrugs on Acetic Acid-induced Rat Colitis "

    Alireza Garjani; Soodabeh Davaran; Mohamadreza Rashidi; Nasrin Malek

    2004-01-01

    The protective and anti-inflammatory effects of azo and azo-linked polymeric prodrugs of 5-aminosalicylic acid (5-ASA) on acetic acid induced colitis in rats were investigated. Three azo prodrugs; 4,4 -dihydroxy-azobenzene-3-carboxilic acid (azo compound I), 4-hydroxy-azobenzene-3,4-dicarboxilic acid (azo compound II), 4,4-dihydroxy-3-formyl-azobenzene-3-carboxylic acid (azo compound III) and their polyethylene glycol (PEG 6000) derivatives were synthesized. Rats were pretreated orally (1 hou...

  9. The effect of dietary fiber from wheat processing streams on the formation of carboxylic acids and microbiota in the hindgut of rats.

    Haskå, Lina; Andersson, Roger; Nyman, Margareta

    2011-04-13

    Colonic fermentation of dietary fiber produces carboxylic acids and may stimulate the growth of beneficial bacteria. This study investigated how byproducts of wheat processing (distillers' grains and two fractions from the wet fractionation to starch and gluten, one of which was treated with xylanase) affect the composition of the cecal microbiota and the formation of carboxylic acids in rats. Differences were mostly found between diets based on supernatants and pellets, rather than between fiber sources. Cecal pools and levels of most carboxylic acids in portal blood were higher for rats fed the supernatant diets, while cecal pH and ratios of acetic to propionic acid in portal blood were lower. The diet based on supernatant from distillers' grains gave the highest level of bifidobacteria. Molecular weight and solubility are easier to modify with technological processes, which provides an opportunity to optimize these properties in the development of health products. PMID:21391670

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

    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.

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

    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. PMID:26689207

  12. Catabolism of indole-3-acetic acid and 4- and 5-chloroindole-3-acetic acid in Bradyrhizobium japonicum

    Jensen, J B; Egsgaard, H; Van Onckelen, H;

    1995-01-01

    Some strains of Bradyrhizobium japonicum have the ability to catabolize indole-3-acetic acid. Indoleacetic acid (IAA), 4-chloro-IAA (4-Cl-IAA), and 5-Cl-IAA were metabolized to different extents by strains 61A24 and 110. Metabolites were isolated and analyzed by high-performance liquid...... chromatography and conventional mass spectrometry (MS) methods, including MS-mass spectroscopy, UV spectroscopy, and high-performance liquid chromatography-MS. The identified products indicate a novel metabolic pathway in which IAA is metabolized via dioxindole-3-acetic acid, dioxindole, isatin, and 2......-aminophenyl glyoxylic acid (isatinic acid) to anthranilic acid, which is further metabolized. Degradation of 4-Cl-IAA apparently stops at the 4-Cl-dioxindole step in contrast to 5-Cl-IAA which is metabolized to 5-Cl-anthranilic acid. Udgivelsesdato: 1995-Oct...

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

    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

  14. Exploring the reductive capacity of Pyrococcus furiosus. The reduction of carboxylic acids and pyridine nucleotides

    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 acids.Reductions of carboxylic acids are interes

  15. 40 CFR 721.2088 - Carboxylic acids, (C6-C9) branched and linear.

    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...

  16. Catalytic Esterification of Methyl Alcohol with Acetic Acid

    2001-01-01

    Esterification of methyl alcohol with acetic acid catalysed by Amberlyst-15 (cation-exchange resin) was carried out in a batch reactor in the temperature ranging between 318-338 K, at atmospheric pressure. The reaction rate increased with increase in catalyst concentration and reaction temperature, but decreased with an increase in water concentration. Stirrer speed had virtually no effect on the rate under the experimental conditions. The rate data were correlated with a second-order kinetic model based on homogeneous reaction. The apparent activation energy was found to be 22.9kJ.mo1-1 for the formation of methyl acetate. The methyl acetate production was carried out aa batch and continuous in a packed bed restive distillation column with high purity methyl acetate produced.

  17. Qualitative analysis of some carboxylic acids by ion-exclusion chromatography with atmospheric pressure chemical ionization mass spectrometric detection.

    Helale, Murad I H; Tanaka, Kazuhiko; Taoda, Hiroshi; Hu, Wenzhi; Hasebe, Kiyoshi; Haddad, Paul R

    2002-05-17

    A simple, selective and sensitive method for the determination of carboxylic acids has been developed. A mixture of formic, acetic, propionic, valeric, isovaleric, isobutyric, and isocaproic acids has been separated on a polymethacrylate-based weak acidic cation-exchange resin (TSK gel OA pak-A) based on an ion-exclusion chromatographic mechanism with detection using UV-photodiode array, conductivity and atmospheric pressure chemical ionization mass spectrometry (APCI-MS). A mobile phase consisting of 0.85 mM benzoic acid in 10% aqueous methanol (pH 3.89) was used to separate the above carboxylic acids in about 40 min. For LC-MS, the APCI interface was used in the negative ionization mode. Linear plots of peak area versus concentration were obtained over the range 1-30 mM (r2=0.9982) and 1-30 mM (r2=0.9958) for conductimetric and MS detection, respectively. The detection limits of the target carboxylic acids calculated at S/N=3 ranged from 0.078 to 2.3 microM for conductimetric and photometric detection and from 0.66 to 3.82 microM for ion-exclusion chromatography-APCI-MS. The reproducibility of retention times was 0.12-0.16% relative standard deviation for ion-exclusion chromatography and 1.21-2.5% for ion-exclusion chromatography-APCI-MS. The method was applied to the determination of carboxylic acids in red wine, white wine, apple vinegar, and Japanese rice wine. PMID:12108651

  18. A novel synthesis of carbon-labelled quinolone-3-carboxylic acid antibacterials

    Carr, R.M.; Sutherland, D.R. (Glaxo Research and Development Ltd., Greenford (United Kingdom). Isotope Chemistry Group)

    1994-10-01

    3-Iodoquinolones were prepared from the corresponding quinolone-3-carboxylic acids by Hunsdiecker-type iododecarboxylation reactions with lead tetraacetate and iodine. Cyanation of the iodo compounds with mixtures of potassium [[sup 13]C]cyanide and copper (1) iodide, gave [3-[sup 13]C]cyanoquinolones which on acidic hydrolysis afforded quinolone-[3-[sup 13]C]carboxylic acids. In this way, nalidixic acid, an immediate precursor of norfloxacin, and quinolone WIN57273 were labelled with carbon-13 in the metabolically stable carboxylic acid fragment. (author).

  19. Efficient Debromination of Vicinal (, (-Dibromo Carboxylic Acid Derivatives with the Sm/HOAc System

    2002-01-01

    The α, β vicinal dibromo carboxylic acid and its derivatives were debrominated with Sm/HOAc system to afford the corresponding cinnamic acid and its derivatives in good yields under mild conditions.

  20. Highly Concentrated Acetic Acid Poisoning: 400 Cases Reviewed

    Konstantin Brusin

    2012-12-01

    Full Text Available Background: Caustic substance ingestion is known for causing a wide array of gastrointestinal and systemic complications. In Russia, ingestion of acetic acid is a major problem which annually affects 11.2 per 100,000 individuals. The objective of this study was to report and analyze main complications and outcomes of patients with 70% concentrated acetic acid poisoning. Methods: This was a retrospective study of patients with acetic acid ingestion who were treated at Sverdlovsk Regional Poisoning Treatment Center during 2006 to 2012. GI mucosal injury of each patient was assessed with endoscopy according to Zargar’s scale. Data analysis was performed to analyze the predictors of stricture formation and mortality. Results: A total of 400 patients with median age of 47 yr were included. GI injury grade I was found in 66 cases (16.5%, IIa in 117 (29.3%, IIb in 120 (30%, IIIa in 27 (16.7% and IIIb in 70 (17.5%. 11% of patients developed strictures and overall mortality rate was 21%. Main complications were hemolysis (55%, renal injury (35%, pneumonia (27% and bleeding during the first 3 days (27%. Predictors of mortality were age 60 to 79 years, grade IIIa and IIIb of GI injury, pneumonia, stages “I”, “F” and “L” of kidney damage according to the RIFLE scale and administration of prednisolone. Predictors of stricture formation were ingestion of over 100 mL of acetic acid and grade IIb and IIIa of GI injury. Conclusion: Highly concentrated acetic acid is still frequently ingested in Russia with a high mortality rate. Patients with higher grades of GI injury, pneumonia, renal injury and higher amount of acid ingested should be more carefully monitored as they are more susceptible to develop fatal consequences.          

  1. Characterisation of chitosan solubilised in aqueous formic and acetic acids

    Esam A. El-Hefian

    2009-01-01

    The intrinsic viscosity of chitosan (MW 7.9 x 105 g mol-1) having a high degree of deacetylation and solubilised in aqueous formic and acetic acids was determined at room temperature. Contact angle and conductivity of the chitosan solutions were also studied. The values of critical coagulation concentration (CCC) were then obtained from the plots of contact angle or conductivity versus concentration.

  2. First Acetic Acid Survey with CARMA in Hot Molecular Cores

    Shiao, Y -S Jerry; Remijan, Anthony J; Snyder, Lewis E; Friedel, Douglas N

    2010-01-01

    Acetic acid (CH$_3$COOH) has been detected mainly in hot molecular cores where the distribution between oxygen (O) and nitrogen (N) containing molecular species is co-spatial within the telescope beam. Previous work has presumed that similar cores with co-spatial O and N species may be an indicator for detecting acetic acid. However, does this presumption hold as higher spatial resolution observations become available of large O and N-containing molecules? As the number of detected acetic acid sources is still low, more observations are needed to support this postulate. In this paper, we report the first acetic acid survey conducted with the Combined Array for Research in Millimeter-wave Astronomy (CARMA) at 3 mm wavelengths towards G19.61-0.23, G29.96-0.02 and IRAS 16293-2422. We have successfully detected CH$_3$COOH via two transitions toward G19.61-0.23 and tentatively confirmed the detection toward IRAS 16293-2422 A. The determined column density of CH$_3$COOH is 2.0(1.0)$\\times 10^{16}$ cm$^{-2}$ and the...

  3. Acid stress adaptation protects saccharomyces cerevisiae from acetic acid-induced programme cell death

    Giannattasio, Sergio; Guaragnella, Nicoletta; Côrte-Real, Manuela; Passarella, Salvatore; Marra, Ersilia

    2005-01-01

    In this work evidence is presented that acid stress adaptation protects Saccharomyces cerevisiae from acetic acid-mediated programmed cell death. Exponential-phase yeast cells, non-adapted or adapted to acid stress by 30 min incubation in rich medium set at pH 3.0 with HCl, have been exposed to increasing concentrations of acetic acid and time course changes of cell viability have been assessed. Adapted cells, in contrast to non-adapted cells, when exposed to 80 mM acetic acid for 200 min ...

  4. Fries Rearrangement of Phenyl Acetate over Solid Acid Catalyst

    2002-01-01

    A silica-supported zirconium based solid acid (ZS) has been used as catalyst for the Fries rearrangement of phenyl acetate (PA). The catalyst showed a higher PA conversion activity and a much higher selectivity for o-hydroxyacetophenone (o-HAP) than for strongly acidic zeolite catalysts. The supported catalyst was characterized by XRD, IR, XPS, pyridine-TPD and the surface area measurements. The catalytic properties were influenced significantly by pretreatment temperature.

  5. Fries Rearrangement of Phenyl Acetate over Solid Acid Catalyst

    CanXiongGUO; YanLIU; 等

    2002-01-01

    A silica-supported zirconium based solid acid (ZS) has been used as catalyst for the Fries rearrangement of phenyl acetate (PA). The catalyst showed a higher PA conversion activity and a much higher selectivity for o-hydroxyacetophenone (o-HAP) than for strongly acidic zeolite catalysts. The supported catalyst was characterized by XRD,IR,XPS,pyridine-TPD and the surface area measurements. The catalytic properties were influenced significantly by pretreatment temperature.

  6. Acrylic acid obtaining from methanol and acetic acid in the presence of complex oxide catalysts

    Небесний, Роман Володимирович; Піх, Зорян Григорович; Шпирка, Ірина Іванівна; Івасів, Володимир Васильович; Небесна, Юлія Віталіївна; Фуч, Уляна Василівна

    2015-01-01

    The purpose of this work is to research process of single-stage acrylic acid obtaining from methanol and acetic acid, namely: to develop effective catalysts for the process of methanol oxidation to formaldehyde with its further aldol condensation with acetic acid to acrylic acid, and to determine optimum conditions for the process. Complex oxide catalysts consisting of oxides of boron, phosphorus, tungsten and vanadium supported on the silica gel have been investigated. The effect of vanadium...

  7. Occurrence and metabolism of 7-hydroxy-2-indolinone-3-acetic acid in Zea mays

    Lewer, P.; Bandurski, R. S.

    1987-01-01

    7-Hydroxy-2-indolinone-3-acetic acid was identified as a catabolite of indole-3-acetic acid in germinating kernels of Zea mays and found to be present in amounts of ca 3.1 nmol/kernel. 7-Hydroxy-2-indolinone-3-acetic acid was shown to be a biosynthetic intermediate between 2-indolinone-3-acetic acid and 7-hydroxy-2-indolinone-3-acetic acid-7'-O-glucoside in both kernels and roots of Zea mays. Further metabolism of 7-hydroxy-2-[5-3H]-indolinone-3-acetic acid-7'-O-glucoside occurred to yield tritiated water plus, as yet, uncharacterized products.

  8. High resolution acetic acid survey and water vapor radiometer

    Shiao, Yu-Shao

    2008-08-01

    Planets, comets, stars, galaxies and the interstellar medium (ISM) emit complex but distinct molecular spectra. These spectra reveal the chemical composition and physical conditions in the objects. For example, many biologically important molecules, such as acetic acid, formic acid, vinyl cyanide and ethyl cyanide, have been detected in hot molecular cores in the ISM. A diversity of molecules creates complicated and yet interesting astrochemistry in hot cores. However, the formation mechanisms of large molecules are still unclear. Hence large molecule observations are essential to understand hot core chemistry. Among these molecules, acetic acid is one of the most important large species in hot cores. It is a possible precursor of glycine, the simplest amino acid. It only has been detected in high-mass hot cores without oxygen/nitrogen chemical differentiation, which is key to hot core chemical models. Using the Combined Array for Research in Millimeter-wave Astronomy (CARMA), we have conducted an acetic acid survey in hot cores. In our survey, we have discovered a new acetic acid hot core, G19.61-0.23, which also shows no chemical differentiation. Therefore, we suggest that both large oxygen and nitrogen- bearing species play important roles in acetic acid formation. Ground-based interferometric observations are severely affected by atmospheric conditions. Phase correction is a technique to obtain high quality data and achieve great scientific goals. For our acetic acid survey, a better phase correction technique can not only detect weaker transitions of large molecules, but also increase the map resolution of hot cores. Water vapor radiometers (WVRs) are designed to improve the technique by observing tropospheric water vapor along the lines of sight of interferometers. We have numerically demonstrated the importance of phase correction for interferometric observations and examined the water vapor phase correction technique. Furthermore, we have built two WVR

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

    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

  10. Keto-Enol Tautomerizations Catalyzed by Water and Carboxylic Acids

    da Silva, G.

    2009-12-01

    The ability of weakly-bound complexes to influence the kinetics of gas phase reactions, particularly in atmospheric chemistry, has long been speculated. This study uses quantum chemistry and statistical reaction rate theory to identify that bound water molecules can significantly reduce barriers to intramolecular hydrogen shift reactions, via a double-hydrogen-shift mechanism. The bound water molecule directly participates in the hydrogen shift reaction, exchanging a H atom with its counterpart. For the vinyl alcohol to acetaldehyde keto-enol tautomerization this mechanism cuts the reaction barrier approximately in half, reducing it by over 30 kcal mol-1. In contrast, while a non-participatory ‘bystander’ water molecule also reduces the hydrogen shift barrier, it is only by around 3 kcal/mol. When a carboxylic acid replaces water in the double-hydrogen-shift mechanism the barrier to keto-enol tautomerization is decimated, reduced to less than 6 kcal/mol (around 15 kcal/mol in the reverse direction). This results from reduced strain in the hydrogen shift transition state, and achieves enol lifetimes in the troposphere that become short on relevant timescales. Rapid enol to ketone isomerizations are currently required to explain the oxidation products of isoprene. The wider significance of rapid hydrogen shift reactions in atmospherically relevant molecules and radicals is also explored.

  11. 40 CFR 721.4097 - 7-Oxabicyclo[4.1.0]heptane-3-carboxylic acid, methyl ester.

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false 7-Oxabicyclo heptane-3-carboxylic acid... Specific Chemical Substances § 721.4097 7-Oxabicyclo heptane-3-carboxylic acid, methyl ester. (a) Chemical...-oxabicyclo heptane-3-carboxylic acid, methyl ester (PMN P-98-101) is subject to reporting under this...

  12. Simultaneous production of acetic and gluconic acids by a thermotolerant Acetobacter strain during acetous fermentation in a bioreactor.

    Mounir, Majid; Shafiei, Rasoul; Zarmehrkhorshid, Raziyeh; Hamouda, Allal; Ismaili Alaoui, Mustapha; Thonart, Philippe

    2016-02-01

    The activity of bacterial strains significantly influences the quality and the taste of vinegar. Previous studies of acetic acid bacteria have primarily focused on the ability of bacterial strains to produce high amounts of acetic acid. However, few studies have examined the production of gluconic acid during acetous fermentation at high temperatures. The production of vinegar at high temperatures by two strains of acetic acid bacteria isolated from apple and cactus fruits, namely AF01 and CV01, respectively, was evaluated in this study. The simultaneous production of gluconic and acetic acids was also examined in this study. Biochemical and molecular identification based on a 16s rDNA sequence analysis confirmed that these strains can be classified as Acetobacter pasteurianus. To assess the ability of the isolated strains to grow and produce acetic acid and gluconic acid at high temperatures, a semi-continuous fermentation was performed in a 20-L bioreactor. The two strains abundantly grew at a high temperature (41°C). At the end of the fermentation, the AF01 and CV01 strains yielded acetic acid concentrations of 7.64% (w/v) and 10.08% (w/v), respectively. Interestingly, CV01 was able to simultaneously produce acetic and gluconic acids during acetic fermentation, whereas AF01 mainly produced acetic acid. In addition, CV01 was less sensitive to ethanol depletion during semi-continuous fermentation. Finally, the enzymatic study showed that the two strains exhibited high ADH and ALDH enzyme activity at 38°C compared with the mesophilic reference strain LMG 1632, which was significantly susceptible to thermal inactivation. PMID:26253254

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

    Mixed ligand complexes of UO22+ with bidentate carboxylic and phenolic acids have been studied potentiometrically at 30 ± 0.1degC and μ=0.2M (NaClO4). 1:1 and 1:2 complexes of UO22+ 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

  14. [Conversion of acetic acid to methane by thermophiles

    Zinder, S.H.

    1993-01-01

    The primary goal of this project is to obtain a better understanding of thermophilic microorganisms which convert acetic acid to CH[sub 4]. The previous funding period represents a departure from earlier research in this laboratory, which was more physiological and ecological. The present work is centered on the biochemistry of the thermophile Methanothrix sp. strain CALS-1. this organism presents a unique opportunity, with its purity and relatively rapid growth, to do comparative biochemical studies with the other major acetotrophic genus Methanosarcina. We previously found that Methanothrix is capable of using acetate at concentrations 100 fold lower than Methanosarcina. This finding suggests that there are significant differences in the pathways of methanogenesis from acetate in the two genera.

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

    Rahmi Kasımoğulları; Makbule Maden; Samet Mert

    2012-01-01

    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 (58) were obtained from the reaction of 3 and 4 with various diamines and also a ;#946;-hydroxy ester (9) deri...

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

    Kasımoğulları, Rahmi; Maden, Makbule; Mert, Samet

    2012-01-01

    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 β-hydroxy ester (9)...

  17. Liquid-Liquid equilibria of the water-acetic acid-butyl acetate system

    E. Ince

    2002-04-01

    Full Text Available Experimental liquid-liquid equilibria of the water-acetic acid-butyl acetate system were studied at temperatures of 298.15± 0.20, 303.15± 0.20 and 308.15± 0.20 K. Complete phase diagrams were obtained by determining solubility and tie-line data. The reliability of the experimental tie-line data was ascertained by using the Othmer and Tobias correlation. The UNIFAC group contribution method was used to predict the observed ternary liquid-liquid equilibrium (LLE data. It was found that UNIFAC group interaction parameters used for LLE did not provide a good prediction. Distribution coefficients and separation factors were evaluated for the immiscibility region.

  18. Photophysics of indole-2-carboxylic acid (I2C) and indole-5-carboxylic acid (I5C): heavy atom effect.

    Kowalska-Baron, Agnieszka; Gałęcki, Krystian; Wysocki, Stanisław

    2013-12-01

    In this study the effect of carboxylic group substitution in the 2 and 5 position of indole ring on the photophysics of the parent indole chromophore has been studied. The photophysical parameters crucial in triplet state decay mechanism of aqueous indole-2-carboxylic acid (I2C) and indole-5-carboxylic acid (I5C) have been determined applying our previously proposed methodology based on the heavy atom effect and fluorescence and phosphorescence decay kinetics [Kowalska-Baron et al., 2012]. The determined time-resolved phosphorescence spectra of I2C and I5C are red-shifted as compared to that of the parent indole. This red-shift was especially evident in the case of I2C and may indicate the possibility of hydrogen bonded complex formation incorporating carbonyl CO, the NH group of I2C and, possibly, surrounding water molecules. The possibility of the excited state charge transfer process and the subsequent electronic charge redistribution in such a hydrogen bonded complex may also be postulated. The resulting stabilization of the I2C triplet state is manifested by its relatively long phosphorescence lifetime in aqueous solution (912 μs). The relatively short phosphorescence lifetime of I5C (56 μs) may be the consequence of more effective ground-state quenching of I5 C triplet state. This hypothesis may be strengthened by the significantly larger value of the determined rate constant of I5C triplet state quenching by its ground-state (4.4 × 10(8)M(-1)s(-1)) as compared to that for indole (6.8 × 10(7)M(-1)s(-1)) and I2C (2.3 × 10(7)M(-1)s(-1)). The determined bimolecular rate constant for triplet state quenching by iodide [Formula: see text] is equal to 1 × 10(4)M(-1)s(-1); 6 × 10(3)M(-1)s(-1) and 2.7 × 10(4)M(-1)s(-1) for indole, I2 C and I5 C, respectively. In order to obtain a better insight into iodide quenching of I2C and I5C triplet states in aqueous solution, the temperature dependence of the bimolecular rate constants for iodide quenching of the

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

    Poole, L.J.; King, C.J.

    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. CO{sub 2} and H{sub 2}S) 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 concentration

  20. Cyclic Comonomers for the Synthesis of Carboxylic Acid and Amine Functionalized Poly(l-Lactic Acid

    Markus Heiny

    2015-03-01

    Full Text Available Degradable aliphatic polyesters such as poly(lactic acid are widely used in biomedical applications, however, they lack functional moieties along the polymer backbone that are amenable for functionalization reactions or could be the basis for interactions with biological systems. Here we present a straightforward route for the synthesis of functional α-ω epoxyesters as comonomers for lactide polymerization. Salient features of these highly functionalized epoxides are versatility in functionality and a short synthetic route of less than four steps. The α-ω epoxyesters presented serve as a means to introduce carboxylic acid and amine functional groups into poly(lactic acid polymers via ring-opening copolymerization.

  1. Production of Bio-gasoline by Co-cracking of Acetic Acid in Bio-oil and Ethanol

    王树荣; 王誉蓉; 蔡勤杰; 郭祚刚

    2014-01-01

    Acetic acid was selected as the model compound representing the carboxylic acids present in bio-oil. This work focuses the co-cracking of acetic acid with ethanol for bio-gasoline production. The influences of reac-tion temperature and pressure on the conversion of reactants as well as the selectivity and composition of the crude gasoline phase were investigated. It was found that increasing reaction temperature benefited the conversion of re-actants and pressurized cracking produced a higher crude gasoline yield. At 400 °C and 1 MPa, the conversion of the reactants reached over 99%and the selectivity of the gasoline phase reached 42.79%(by mass). The gasoline phase shows outstanding quality, with a hydrocarbon content of 100%.

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

    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. PMID:26593586

  3. Acetic acid bacteria spoilage of bottled red wine -- a review.

    Bartowsky, Eveline J; Henschke, Paul A

    2008-06-30

    Acetic acid bacteria (AAB) are ubiquitous organisms that are well adapted to sugar and ethanol rich environments. This family of Gram-positive bacteria are well known for their ability to produce acetic acid, the main constituent in vinegar. The oxidation of ethanol through acetaldehyde to acetic acid is well understood and characterised. AAB form part of the complex natural microbial flora of grapes and wine, however their presence is less desirable than the lactic acid bacteria and yeast. Even though AAB were described by Pasteur in the 1850s, wine associated AAB are still difficult to cultivate on artificial laboratory media and until more recently, their taxonomy has not been well characterised. Wine is at most risk of spoilage during production and the presence of these strictly aerobic bacteria in grape must and during wine maturation can be controlled by eliminating, or at least limiting oxygen, an essential growth factor. However, a new risk, spoilage of wine by AAB after packaging, has only recently been reported. As wine is not always sterile filtered prior to bottling, especially red wine, it often has a small resident bacterial population (Bottled red wines, sealed with natural cork closures, and stored in a vertical upright position may develop spoilage by acetic acid bacteria. This spoilage is evident as a distinct deposit of bacterial biofilm in the neck of the bottle at the interface of the wine and the headspace of air, and is accompanied with vinegar, sherry, bruised apple, nutty, and solvent like off-aromas, depending on the degree of spoilage. This review focuses on the wine associated AAB species, the aroma and flavour changes in wine due to AAB metabolism, discusses the importance of oxygen ingress into the bottle and presents a hypothesis for the mechanism of spoilage of bottled red wine. PMID:18237809

  4. Unimolecular decomposition of formic and acetic acids: A shock tube/laser absorption study

    Elwardany, A.

    2014-07-16

    The thermal decomposition of formic acid (HCOOH) and acetic acid (CH3COOH), two carboxylic acids which play an important role in oxygenate combustion chemistry, were investigated behind reflected shock waves using laser absorption. The rate constants of the primary decomposition pathways of these acids:(HCOOH → CO + H2 O (R 1); HCOOH → CO2 + H2 (R 2); CH3 COOH → CH4 + CO2 (R 3); CH3 COOH → CH2 CO + H2 O (R 4)) were measured using simultaneous infrared laser absorption of CO, CO2 and H2O at wavelengths of 4.56, 4.18 and 2.93 microns, respectively. Reaction test conditions covered temperatures from 1230 to 1821 K and pressures from 1.0 to 6.5 atm for dilute mixtures of acids (0.25-0.6%) in argon. The rate constants of dehydration (R1) and decarboxylation (R2) reactions of formic acid were calculated by fitting exponential functions to the measured CO, CO2 and H2O time-history profiles. These two decomposition channels were found to be in the fall-off region and have a branching ratio, k1/k2, of approximately 20 over the range of pressures studied here. The best-fit Arrhenius expressions of the first-order rates of R1 and R2 were found to be:(k1 (1 atm) = 1.03 × 1011 exp (- 25651 / T) s- 1 (± 37 %); k1 (6.5 atm) = 9.12 × 1012 exp (- 30275 / T) s- 1 (± 32 %); k2 (1 atm) = 1.79 × 108 exp (- 21133 / T) s- 1 (± 41 %); k2 (6.5 atm) = 2.73 × 108 exp (- 20074 / T) s- 1 (± 37 %)). The rate constants for acetic acid decomposition were obtained by fitting simulated profiles, using an acetic acid pyrolysis mechanism, to the measured species time-histories. The branching ratio, k4/k3, was found to be approximately 2. The decarboxylation and dehydration reactions of acetic acid appear to be in the falloff region over the tested pressure range:(k3 (1 atm) = 3.18 × 1011 exp (- 28679 / T) s- 1 (± 30 %); k3 (6 atm) = 3.51 × 1012 exp (- 31330 / T) s- 1 (± 26 %); k4 (1 atm) = 7.9 × 1011 exp (- 29056 / T) s- 1 (± 34 %); k4 (6 atm) = 6.34 × 1012 exp (- 31330 / T) s

  5. Efficient Fixation of Carbon Dioxide by Electrolysis - Facile Synthesis of Useful Carboxylic Acids -

    Masao Tokuda

    2006-01-01

    Electrochemical fixation of atmospheric pressure of carbon dioxide to organic compounds is a useful and attractive method for synthesizing of various carboxylic acids. Electrochemical fixation of carbon dioxide, electrochemical carboxylation, organic halides, organic triflates, alkenes, aromatic compounds, and carbonyl compounds can readily occur in the presence of an atmospheric pressure of carbon dioxide to form the corresponding carboxylic acids with high yields, when a sacrificial anode such as magnesium or aluminum is used in the electrolysis. The electrochemical carboxylation of vinyl bromides was successfully applied for the synthesis of the precursor of nonsteroidal anti-inflammatory agents such as ibuprofen and naproxen. On the other hand, supercritical carbon dioxide (scCO2) has significant potential as an environmentally benign solvent in organic synthesis and it could be used both as a solvent and as a reagent in these electrochemical carboxylations by using a small amount of cosolvent.

  6. Ion-exclusion chromatographic behavior of aliphatic carboxylic acids and benzenecarboxylic acids on a sulfonated styrene--divinylbenzene co-polymer resin column with sulfuric acid containing various alcohols as eluent.

    Ohta, Kazutoku; Towata, Atsuya; Ohashi, Masayoshi

    2003-05-16

    The addition of C1-C7 alcohols (methanol, ethanol, propanol, butanol, heptanol, hexanol and heptanol) to dilute sulfuric acid as eluent in ion-exclusion chromatography using a highly sulfonated styrene-divinylbenzene co-polymer resin (TSKgel SCX) in the H+ form as the stationary phase was carried out for the simultaneous separations of both (a) C1-C7 aliphatic carboxylic acids (formic, acetic, propionic, isobutyric, butyric, isovaleric, valeric, 2-methylvaleric, isocaproic, caproic, 2,2-dimethyl-n-valeric, 2-methylhexanoic, 5-methylhexanoic and heptanoic acids) and (b) benzenecarboxylic acids (pyromellitic, hemimellitic, trimellitic, o-phthalic, m-phthalic, p-phthalic, benzoic and salicylic acids and phenol). Heptanol was the most effective modifier in ion-exclusion chromatography for the improvement of peak shapes and a reduction in retention volumes for higher aliphatic carboxylic acids and benzenecarboxylic acids. Excellent simultaneous separation and relatively highly sensitive conductimetric detection for these C1-C7 aliphatic carboxylic acids were achieved on the TSKgel SCX column (150 x 6 mm I.D.) in 30 min using 0.5 mM sulfuric acid containing 0.025% heptanol as eluent. Excellent simultaneous separation and highly sensitive UV detection at 200 nm for these benzenecarboxylic acids were also achieved on the TSKgel SCX column in 30 min using 5 mM sulfuric acid containing 0.075% heptanol as eluent. PMID:12830881

  7. Effects of intermediate metabolite carboxylic acids of TCA cycle on Microcystis with overproduction of phycocyanin.

    Bai, Shijie; Dai, Jingcheng; Xia, Ming; Ruan, Jing; Wei, Hehong; Yu, Dianzhen; Li, Ronghui; Jing, Hongmei; Tian, Chunyuan; Song, Lirong; Qiu, Dongru

    2015-04-01

    Toxic Microcystis species are the main bloom-forming cyanobacteria in freshwaters. It is imperative to develop efficient techniques to control these notorious harmful algal blooms (HABs). Here, we present a simple, efficient, and environmentally safe algicidal way to control Microcystis blooms, by using intermediate carboxylic acids from the tricarboxylic acid (TCA) cycle. The citric acid, alpha-ketoglutaric acid, succinic acid, fumaric acid, and malic acid all exhibited strong algicidal effects, and particularly succinic acid could cause the rapid lysis of Microcystis in a few hours. It is revealed that the Microcystis-lysing activity of succinic acid and other carboxylic acids was due to their strong acidic activity. Interestingly, the acid-lysed Microcystis cells released large amounts of phycocyanin, about 27-fold higher than those of the control. On the other hand, the transcription of mcyA and mcyD of the microcystin biosynthesis operon was not upregulated by addition of alpha-ketoglutaric acid and other carboxylic acids. Consider the environmental safety of intermediate carboxylic acids. We propose that administration of TCA cycle organic acids may not only provide an algicidal method with high efficiency and environmental safety but also serve as an applicable way to produce and extract phycocyanin from cyanobacterial biomass. PMID:25342454

  8. Acetic Acid Production by an Electrodialysis Fermentation Method with a Computerized Control System

    Nomura, Yoshiyuki; Iwahara, Masayoshi; Hongo, Motoyoshi

    1988-01-01

    In acetic acid fermentation by Acetobacter aceti, the acetic acid produced inhibits the production of acetic acid by this microorganism. To alleviate this inhibitory effect, we developed an electrodialysis fermentation method such that acetic acid is continuously removed from the broth. The fermentation unit has a computerized system for the control of the pH and the concentration of ethanol in the fermentation broth. The electrodialysis fermentation system resulted in improved cell growth an...

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

    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...

  10. Characterisation of chitosan solubilised in aqueous formic and acetic acids

    Esam A. El-hefian

    2009-11-01

    Full Text Available The intrinsic viscosity of chitosan (MW 7.9 x 105 g mol-1 having a high degree of deacetylation and solubilised in aqueous formic and acetic acids was determined at room temperature. Contact angle and conductivity of the chitosan solutions were also studied. The values of critical coagulation concentration (CCC were then obtained from the plots of contact angle or conductivity versus concentration.

  11. Microwave Irradiation Promoted Synthesis of Aryloxy Acetic Acids

    LIN Min; ZHOU Jin-mei; XIA Hai-ping; YANG Rui-feng; LIN Chen

    2004-01-01

    Several aryloxy acetic acids were synthesized under microwave irradiation. The factors, which affect the reaction, were investigated and optimized. It was revealed that the best yields(92.7%-97.4%) were obtained when the molar ratio of the reactants was n(ArOH) : n(NaOH): n(ClCH2CO2H) =1: 2.5: 1.2 with microwave irradiation power of 640 W for 65-85 s.

  12. Kinetics of xylose dehydration into furfural in acetic acid

    Zhou Chen; Weijiang Zhang; Jiao Xu; Pingli Li

    2015-01-01

    In this paper kinetics of xylose dehydration into furfural using acetic acid as catalyst was studied comprehensively and systematical y. The reaction order of both furfural and xylose dehydration was determined and the reaction activation energy was obtalned by nonlinear regression. The effect of acetic acid concentration was also investi-gated. Reaction rate constants were galned. Reaction rate constant of xylose dehydration is k1 ¼ 4:189 . 1010 ½A.0:1676 exp −108:6.1000RT . ., reaction rate constant of furfural degradation is k2 ¼ 1:271 . 104½A.0:1375 exp−63:413.1000RT . and reaction rate constant of condensation reaction is k3 ¼ 3:4051 . 1010½A.0:1676 exp−104:99.1000RT .. Based on this, the kinetics equation of xylose dehydration into furfural in acetic acid was set up according to theory of Dunlop and Furfural generating rate equation is dd½F.t ¼ k1½X.0e−k1t−k2½F.−k3½X.0e−k1t½F.. © 2015 The Chemical Industry and Engineering Society of China, and Chemical Industry Press. Al rights reserved.

  13. Gamma-aminoadamantane carboxylic acids : orientating building blocks in peptide chemistry

    Wanka, Lukas

    2007-01-01

    The present thesis deals with gamma-aminoadamantane carboxylic acids. Allthough the simplest of these structural analogues of GABA were known for decades, no significant peptide chemistry has been disclosed. Therefore, improved syntheses of these compounds were worked out that allowed for facilitated syntheses of already known as well as new members of gamma-aminoadamantane carboxylic acids. Fmoc-/tert. butyl protective group chemistry was utilized to synthesize peptides incorporating the gam...

  14. Ozone-driven daytime formation of secondary organic aerosol containing carboxylic acid groups and alkane groups

    Liu, S.; D. A. Day; J. E. Shields; L. M. Russell

    2011-01-01

    Carboxylic acids are present in substantial quantities in atmospheric particles, and they play an important role in the physical and chemical properties of aerosol particles. During measurements in coastal California in the summer of 2009, carboxylic acid functional groups were exclusively associated with a fossil fuel combustion factor derived from factor analysis of Fourier transform infrared spectroscopic measurements and closely correlated with oxygenated organic factors from aerosol mass...

  15. Probing the orthosteric binding site of GABAA receptors with heterocyclic GABA carboxylic acid bioisosteres

    Petersen, Jette G; Bergmann, Rikke; Krogsgaard-Larsen, Povl; Balle, Thomas; Frølund, Bente

    2013-01-01

    selective and potent GABAAR agonists. This review investigates the use of heterocyclic carboxylic acid bioisosteres within the GABAAR area. Several heterocycles including 3-hydroxyisoxazole, 3-hydroxyisoxazoline, 3-hydroxyisothiazole, and the 1- and 3-hydroxypyrazole rings have been employed in order to map...... the orthosteric binding site. The physicochemical properties of the heterocyclic moieties making them suitable for bioisosteric replacement of the carboxylic acid in the molecule of GABA are discussed. A variety of synthetic strategies for synthesis of the heterocyclic scaffolds are available...

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

    Olesen, Solveig Gaarn; Hammerum, Steen

    2009-01-01

    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....

  17. Copper-catalyzed intermolecular oxyamination of olefins using carboxylic acids and O-benzoylhydroxylamines

    Hemric, Brett N

    2016-01-01

    Summary This paper reports a novel approach for the direct and facile synthesis of 1,2-oxyamino moieties via an intermolecular copper-catalyzed oxyamination of olefins. This strategy utilizes O-benzoylhydroxylamines as an electrophilic amine source and carboxylic acids as a nucleophilic oxygen source to achieve a modular difunctionalization of olefins. The reaction proceeded in a regioselective manner with moderate to good yields, exhibiting a broad scope of carboxylic acid, amine, and olefin substrates. PMID:26877805

  18. Comparative structure analysis of non-polar organic ferrofluids stabilized by saturated mono-carboxylic acids.

    Avdeev, M V; Bica, D; Vékás, L; Aksenov, V L; Feoktystov, A V; Marinica, O; Rosta, L; Garamus, V M; Willumeit, R

    2009-06-01

    The structure of ferrofluids (magnetite in decahydronaphtalene) stabilized with saturated mono-carboxylic acids of different chain lengths (lauric, myristic, palmitic and stearic acids) is studied by means of magnetization analysis and small-angle neutron scattering. It is shown that in case of saturated acid surfactants, magnetite nanoparticles are dispersed in the carrier approximately with the same size distribution whose mean value and width are significantly less as compared to the classical stabilization with non-saturated oleic acid. The found thickness of the surfactant shell around magnetite is analyzed with respect to stabilizing properties of mono-carboxylic acids. PMID:19376524

  19. Ozone-driven photochemical formation of carboxylic acid groups from alkane groups

    S. Liu

    2011-03-01

    Full Text Available Carboxylic acids are ubiquitous in atmospheric particles, and they play an important role in the physical and chemical properties of aerosol particles. During measurements in coastal California in the summer of 2009, carboxylic acid functional groups were highly associated with trajectories from an industrial region with high organic mass (OM, likely from fossil fuel combustion emissions. The concentration of carboxylic acid groups peaked during daytime, suggesting a photochemical secondary formation mechanism. This daytime increase in concentration was tightly correlated with O3 mixing ratio, indicating O3 was the likely driver in acid formation. Based on the diurnal cycles of carboxylic acid and alkane groups, the covariation of carboxylic acid groups with O3, and the composition of the Combustion factor resulted from the factor analyses, gas-phase alkane oxidation by OH radicals to form dihyfrofuran followed by further oxidation of dihydrofuran by O3 is the likely acid formation mechanism. Using the multi-day average of the daytime increase of carboxylic acid group concentrations and m/z 44-based Aged Combustion factor, we estimated the lower-bound contributions of secondary organic aerosol (SOA formed in 12-h daytime of processing in a single day to be 30% of the carboxylic acid groups and 25–45% of the Combustion factor concentration. These unique ambient observations of photochemically-driven acid formation suggest that gas-phase alkanes might be important sources of SOA formation in this coastal region.

  20. Change in the plasmid copy number in acetic acid bacteria in response to growth phase and acetic acid concentration.

    Akasaka, Naoki; Astuti, Wiwik; Ishii, Yuri; Hidese, Ryota; Sakoda, Hisao; Fujiwara, Shinsuke

    2015-06-01

    Plasmids pGE1 (2.5 kb), pGE2 (7.2 kb), and pGE3 (5.5 kb) were isolated from Gluconacetobacter europaeus KGMA0119, and sequence analyses revealed they harbored 3, 8, and 4 genes, respectively. Plasmid copy numbers (PCNs) were determined by real-time quantitative PCR at different stages of bacterial growth. When KGMA0119 was cultured in medium containing 0.4% ethanol and 0.5% acetic acid, PCN of pGE1 increased from 7 copies/genome in the logarithmic phase to a maximum of 12 copies/genome at the beginning of the stationary phase, before decreasing to 4 copies/genome in the late stationary phase. PCNs for pGE2 and pGE3 were maintained at 1-3 copies/genome during all phases of growth. Under a higher concentration of ethanol (3.2%) the PCN for pGE1 was slightly lower in all the growth stages, and those of pGE2 and pGE3 were unchanged. In the presence of 1.0% acetic acid, PCNs were higher for pGE1 (10 copies/genome) and pGE3 (6 copies/genome) during the logarithmic phase. Numbers for pGE2 did not change, indicating that pGE1 and pGE3 increase their PCNs in response to acetic acid. Plasmids pBE2 and pBE3 were constructed by ligating linearized pGE2 and pGE3 into pBR322. Both plasmids were replicable in Escherichia coli, Acetobacter pasteurianus and G. europaeus, highlighting their suitability as vectors for acetic acid bacteria. PMID:25575969

  1. Photoelectrochemical properties of WO3 nanoparticulate thin films prepared by carboxylic acid-assisted electrodeposition

    Optimisation of particle sizes of WO3 films is important for photoelectrochemical applications. However, most of the developed size-controlled synthesis techniques involve complicated instruments or vacuum systems. The present work presents an alternative method using carboxylic acid-assisted electrodeposition where WO3 thin films were deposited from peroxotungstic acid (PTA) solution containing different carboxylic acids (formic, oxalic, citric). The effects of carboxylic acids on the electrodeposition and the resultant morphological, mineralogical, optical, and photoelectrochemical properties of the WO3 films were investigated. The analysis showed that the films consisted of equiaxed nanoparticulate monoclinic WO3. The deposition thicknesses and the average grain (individual particle and agglomerate) sizes of the films were dependent on the amount of hydronium ions and the molecular weight and associated sizes of the conjugate bases released upon the dissociation of carboxylic acids in the PTA solutions, which result in hydrogen bond formation and molecular dispersion. The photocurrent densities of the films deposited with carboxylic acids were greater than that of the film deposited from pure PTA. These differences were attributed to improvements in (1) grain size, which controls photogenerated electron-hole transport, and (2) effective grain boundary area, which controls the numbers of active reaction sites and electron-hole recombination sites. - Highlights: • Carboxylic acid-assisted electrodeposition of WO3 films from peroxotungstic acid. • The types of carboxylic acids control the deposition rates and microstructure. • WO3 grain sizes and effective grain boundary areas determine the photocurrents. • Maximal photocurrent measured in the smallest-aggregate films (∼ 83 nm)

  2. Gas-Phase Structures of Ketene and Acetic Acid from Acetic Anhydride Using Very-High-Temperature Gas Electron Diffraction.

    Atkinson, Sandra J; Noble-Eddy, Robert; Masters, Sarah L

    2016-03-31

    The gas-phase molecular structure of ketene has been determined using samples generated by the pyrolysis of acetic anhydride (giving acetic acid and ketene), using one permutation of the very-high-temperature (VHT) inlet nozzle system designed and constructed for the gas electron diffraction (GED) apparatus based at the University of Canterbury. The gas-phase structures of acetic anhydride, acetic acid, and ketene are presented and compared to previous electron diffraction and microwave spectroscopy data to show improvements in data extraction and manipulation with current methods. Acetic anhydride was modeled with two conformers, rather than a complex dynamic model as in the previous study, to allow for inclusion of multiple pyrolysis products. The redetermined gas-phase structure of acetic anhydride (obtained using the structure analysis restrained by ab initio calculations for electron diffraction method) was compared to that from the original study, providing an improvement on the description of the low vibrational torsions compared to the dynamic model. Parameters for ketene and acetic acid (both generated by the pyrolysis of acetic anhydride) were also refined with higher accuracy than previously reported in GED studies, with structural parameter comparisons being made to prior experimental and theoretical studies. PMID:26916368

  3. The effect of oral sodium acetate administration on plasma acetate concentration and acid-base state in horses

    Lindinger Michael I

    2007-12-01

    Full Text Available Abstract Aim Sodium acetate (NaAcetate has received some attention as an alkalinizing agent and possible alternative energy source for the horse, however the effects of oral administration remain largely unknown. The present study used the physicochemical approach to characterize the changes in acid-base status occurring after oral NaAcetate/acetic acid (NAA administration in horses. Methods Jugular venous blood was sampled from 9 exercise-conditioned horses on 2 separate occasions, at rest and for 24 h following a competition exercise test (CET designed to simulate the speed and endurance test of 3-day event. Immediately after the CETs horses were allowed water ad libitum and either: 1 8 L of a hypertonic NaAcetate/acetic acid solution via nasogastric tube followed by a typical hay/grain meal (NAA trial; or 2 a hay/grain meal alone (Control trial. Results Oral NAA resulted in a profound plasma alkalosis marked by decreased plasma [H+] and increased plasma [TCO2] and [HCO3-] compared to Control. The primary contributor to the plasma alkalosis was an increased [SID], as a result of increased plasma [Na+] and decreased plasma [Cl-]. An increased [Atot], due to increased [PP] and a sustained increase in plasma [acetate], contributed a minor acidifying effect. Conclusion It is concluded that oral NaAcetate could be used as both an alkalinizing agent and an alternative energy source in the horse.

  4. Detection of CIN by naked eye visualization after application of acetic acid.

    Londhe M; George S; Seshadri L

    1997-01-01

    A prospective study was undertaken to determine the sensitivity and specificity of acetic application to the cervix followed by naked eye visualization as a screening test for detection of cervical intraepithelial neoplasia. Three hundred and seventy two sexually active woman in the reproductive age group were studied. All the women underwent Papanicolaou test, acetic acid test and colposcopy. One hundred and seventy five woman were acetic acid test negative, 197 women were acetic acid test p...

  5. Application of IBX Method for the Synthesis of Ketones from Carboxylic Acids

    KARABULUT, H. R. Ferhat; KAÇAN, Mesut

    2003-01-01

    Methoxy phenyl propionic acid and some derivatives are converted to ketones using a new method. All classical methods to obtain ketones from carboxylic acids via acid halide consistently gave very low yields and regularly generated intermolecular cyclisation products or polymeric materials. However, high ketones yields are obtained by using the new IBX method.

  6. KINETIC STUDY OF CARBONYLATION OF METHANOL TO ACETIC ACID AND ACETIC ANHYDRIDE OVER A NOVEL COPOLYMER- BOUND CIS- DICARBONYLRHODIUM COMPLEX

    CHEN Yuying; YUAN Guoqing; CHEN Rongyao

    1989-01-01

    The kinetic study of carbonylation of methanol-acetic acid mixture to acetic acid and acetic anhydride over a cis-dicarbonylrhodium complex (MVM' Rh)coordinated with the ethylene diacrylate (M')crosslinked copolymer of methyl acrylate (M) and 2 - vinylpyridine (V) shows that the rate of reaction is zero order with respect to both reactants methanol and carbon monoxide, but first order in the concentrations of promoter methyl iodide and rhodium in the complex . Polar solvents can accelerate the reaction .Activation parameters were calculated from the experimental results, being comparable to that of the homogeneous system . A mechanism similar to that of soluble rhodium catalyst was proposed .

  7. Kinetics of esterification of methanol and acetic acid with mineral homogeneous acid catalyst

    Mallaiah Mekala; Venkat Reddy Goli

    2015-01-01

    In this work, esterification of acetic acid and methanol to synthesize methyl acetate in a batch stirred reactor is studied in the temperature range of 305.15–333.15 K. Sulfuric acid is used as the homogeneous catalyst with concentrations ranging from 0.0633 mol·L−1 to 0.3268 mol·L−1. The feed molar ratio of acetic acid to methanol is varied from 1:1 to 1:4. The influences of temperature, catalyst concentration and reactant concentration on the reaction rate are investigated. A second order kinetic rate equation is used to correlate the experimental data. The forward and backward reaction rate constants and activation energies are determined from the Arrhenius plot. The developed kinetic model is compared with the models in literature. The developed kinetic equation is useful for the simulation of reactive distillation column for the synthesis of methyl acetate.

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

    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.

  9. Conversion regular patterns of acetic acid,propionic acid and butyric acid in UASB reactor

    LIU Min; REN Nan-qi; CHEN Ying; ZHU Wen-fang; DING Jie

    2004-01-01

    On the basis of continuous tests and batch tests, conversion regular patterns of acetate, propionate and butyrate in activated sludge at different heights of the UASB reactor were conducted. Results indicated that the conversion capacity of the microbial is decided by the substrate characteristic when sole VFA is used as the only substrate. But when mixed substrates are used,the conversion regulations would have changed accordingly. Relationships of different substrates vary according to their locations. In the whole reactor, propionate's conversion is restrained by acetate and butyrate of high concentration. On the top and at the bottom of the reactor, conversion of acetate, but butyrate, is restrained by propionate. And in the midst, acetate's conversion is accelerated by propionate while that of butyrate is restrained. It is proved, based on the analysis of specific conversion rate, that the space distribution of the microbe is the main factor that affects substrates' conversion. The ethanol-type fermentation of the acidogenic-phase is the optimal acid-type fermentation for the two-phase anaerobic process.

  10. EFFECT OF GOSSYPOL ACETIC ACID ON CHROMOSOME ABERRATIONS AND ANEUPLOIDIES IN OOCYTES AND ZYGOTES OF MICE

    WANGRen-Li; ZHANGZhong-Shu

    1989-01-01

    It was reported that gossypol acetic acid could effectively inhibit th~ implantation in ratA. This finding indicated that gossypol acet/c acid might also be used as a female contraceptive. The Present study further investigated the genetic effect of gossypol acetic

  11. Palladium(II)-Catalyzed Tandem Synthesis of Acenes Using Carboxylic Acids as Traceless Directing Groups.

    Kim, Kiho; Vasu, Dhananjayan; Im, Honggu; Hong, Sungwoo

    2016-07-18

    A straightforward synthetic strategy for generating useful anthracene derivatives was developed involving palladium(II)-catalyzed tandem transformation with carboxylic acids as traceless directing groups. Carboxyl-directed C-H alkenylation, carboxyl-directed secondary C-H activation and rollover, intramolecular C-C bond formation, and decarboxylative aromatization are proposed as the key steps in the tandem reaction pathway. This novel synthetic route utilizes a broad range of substrates and provides a convenient synthetic tool that allows access to acenes. PMID:27244536

  12. Probiotic and Acetic Acid Effect on Broiler Chickens Performance

    Martin Král

    2011-05-01

    Full Text Available Probiotics and organic acids are widely accepted as an alternative to in-feed antibiotics in poultry production. We carried the experiment with broiler chickens. In experiment we research effect of probiotic and acetic acids on the performance of broiler chickens. A total number of 200 one day old broiler chickens were distributed to two dietary groups. Broiler chickens in control group were fed with standard feed mixture and experimental group 1% vinegar contained 5% acetic acid used in drinking water and probiotics mixed with feed mixture. Body weight, FCR and GIT pH were recorded. The performance showed no statistically significant increase in body weight (P>0.05 in the weeks 1, 2, 3 and 4 of age. The body weight of broiler chickens was significant increase (P0.05 in weeks 5, and 6 of age. In different segments of the GIT was not statistically significant (P>0.05 difference of pH between the control and experimental groups.

  13. Expedited Synthesis of Benzofuran-2-Carboxylic Acids via Microwave-Assisted Perkin Rearrangement Reaction

    Marriott, Karla-Sue C.; Bartee, Rena; Morrison, Andrew Z.; Stewart, Leonard; Wesby, Julian

    2012-01-01

    3-Halocoumarins are readily converted into benzofuran-2-carboxylic acids via a Perkin (coumarin-benzofuran ring contraction) rearrangement reaction. This rearrangement entails initial base catalyzed ring fission. The resulting phenoxide anion then attacks a vinyl halide to produce the final benzofuran moiety. We explored this reaction under microwave reaction conditions and were able to significantly reduce reaction times as well as obtain very high yields of a series of benzofuran-2-carboxyl...

  14. 2-(2-Chlorophenyl-5-methyl-1,3-dioxane-5-carboxylic acid

    Guo-Kai Jia

    2012-07-01

    Full Text Available In the title compound, C12H13ClO4, the 1,3-dioxane ring adopts a chair conformation and the 2-chlorobenzene and methyl substituents occupy equatorial sites. The carboxyl group is in an axial inclination. In the crystal, carboxylic acid inversion dimers linked by pairs of O—H...O hydrogen bonds generate R22(8 loops.

  15. Kinetic Modeling of Esterification of Ethylene Glycol with Acetic Acid

    The reaction kinetics of the esterification of ethylene glycol with acetic acid in the presence of cation exchange resin has been studied and kinetic models based on empirical and Langmuir approach has been developed. The Langmuir based model involving eight kinetic parameters fits experimental data much better compared to empirical model involving four kinetic parameters. The effect of temperature and catalyst loading on the reaction system has been analyzed. Further, the activation energy and frequency factor of the rate constants for Langmuir based model has been estimated.

  16. Environmental Risk Limits for Ethylene Diamine Tetra Acetic acid (EDTA)

    Kalf DF; Hoop MAGT van den; Rila JP; Posthuma C; Traas TP; SEC

    2003-01-01

    In this report maximum permissible concentration (MPC) and negligible concentration (NC) in water are derived for Ethylene Diamine Tetra Acetic acid (EDTA; CAS No. 64-02-8, EINECS No. 200-573-9), based on the EU risk assessment report for this compound. The Maximum Permissible Concentration (MPC) for the water compartment is 2.2 mg/l, and the Negligible Concentration (NC) is 0.022 mg/l. Calculation of MPCs for sediment or soil is not possible due to complex speciation of EDTA.

  17. Ascorbic acid absorption in Crohn's disease. Studies using L-[carboxyl-14C]ascorbic acid

    Total body pool and intestinal absorption of ascorbic acid were studied in 12 patients undergoing operation for Crohn's disease (six with fistulae and six without) and in six control patients undergoing operation for reasons other than Crohn's disease. L-[carboxyl-14C]Ascorbic acid, 0.19-0.40 megabecquerels (MBq), was given orally. After a period of equilibration, the labeled ascorbic acid was flushed out of the patient's body tissues using large doses of unlabeled ascorbic acid. Intestinal absorption of ascorbic acid, assessed from the total cumulative urinary 14C recovery, was found to be similar in patients with fistulizing Crohn's disease (73.9 +/- 8.45%), those without fistulas (72.8 +/- 11.53%), and in controls (80.3 +/- 8.11%). Total body pools of ascorbic acid, calculated using the plasma 14C decay curves, were similar in patients with Crohn's disease with fistulas (17.1 +/- 5.91 mg/kg), patients without fistulas (9.6 +/- 3.58 mg/kg), and in controls (13.3 +/- 4.28 mg/kg). The results indicate that ascorbic acid absorption is normal in patients with both fistulizing and nonfistulizing Crohn's disease. The results suggest that routine supplements of vitamin C are not necessary unless oral ascorbic acid intake is low

  18. Chiral trans-1,2-diaminocyclohexane derivatives as chiral solvating agents for carboxylic acids

    Mariappan Periasamy; Manasi Dalai; Meduri Padmaja

    2010-07-01

    Efficient use of the readily accessible chiral 2-symmetric acyclic diamines (1-2) as well as macrocyclic amines (3-5) containing trans-1,2-diaminocyclohexyl moiety as chiral solvating agents (CSA) for the determination of enantiomeric excess of representative carboxylic acids (6-7) and an amino acid derivative (8) is illustrated. The enantiomeric composition of different carboxylic acids estimated here by the 1H NMR method, based on the integration of the corresponding methine proton signals are in good correlation with that determined using HPLC method. The data are in accordance with the formation of multimolecular diastereomeric complexes in solution, which render good splitting of NMR signals for the enantiomers of representative carboxylic acids as well as for -Ts-phenylglycine (up to = 0.295 ppm, 118 Hz).

  19. Communication: Physical origins of ionization potential shifts in mixed carboxylic acids and water complexes

    Gu, Quanli; Tang, Zhen; Su, Peifeng; Wu, Wei; Yang, Zhijun; Trindle, Carl O.; Knee, Joseph L.

    2016-08-01

    The ionization potential (IP) of the aromatic alpha hydroxy carboxylic acid, 9-hydroxy-9-fluorene carboxylic acid (9HFCA), is shifted by complexation with hydrogen bonding ligands such as water and formic acid. Generalized Kohn-Sham energy decomposition analysis decomposes the intermolecular binding energies into a frozen energy term, polarization, correlation, and/or dispersion energy terms, as well as terms of geometric relaxation and zero point energy. We observe that in each dimer the attractive polarization always increases upon ionization, enhancing binding in the cation and shifting the IP toward the red. For 9HFCA—H2O, a substantial decrease of the repulsive frozen energy in cation further shifts the IP toward red. For 9HFCA—HCOOH, the increase of the frozen energy actually occurs in the cation and shifts the IP toward blue. Consistent with the experimental measurements, our analysis provides new, non-intuitive perspectives on multiple hydrogen bonds interactions in carboxylic acids and water complexes.

  20. Photosensitization of Nanocrystalline TiO2 Electrode Modifiedwith C60 Carboxylic Acid Derivatives

    张文; 史亚茹; 甘良兵; 黄春辉; 王艳琴; 虎民

    2001-01-01

    C60 carboxylic acid derivatives can be readily adsorbed on the surface of nanocrystalline TiO2 films act as charge-transfer sensitizer. The electron transport from TiO2 to the C60 derivatives results in the generation of the cathodic photocurrent. The short-circuit photocurrent of a C60 tetracarboxylic acid is 0.45 μA/cm2 under 464 um light illumination. The photoelectric behaviour of ITO electrodes modified by the same C60 carboxylic acids is different from that of the modified TiO2 electrodes, and shows anodic photocurrent.

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

    GÖKSU, Süleyman; UĞUZ, Metin Tansu

    2005-01-01

    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...

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

    The pseudotetrahedral complexes of [Cu(PPh3)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(PPh3)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%

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

    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%.

  4. Use of potassium-form cation-exchange resin as a conductimetric enhancer in ion-exclusion chromatography of aliphatic carboxylic acids.

    Iwata, Tomotaka; Mori, Masanobu; Itabashi, Hideyuki; Tanaka, Kazuhiko

    2009-09-15

    In this study, a cation-exchange resin (CEX) of the K(+)-form, i.e., an enhancer resin, is used as a postcolumn conductimetric enhancer in the ion-exclusion chromatography of aliphatic carboxylic acids. The enhancer resin is filled in the switching valve of an ion chromatograph; this valve is usually used as a suppressor valve in ion-exchange chromatography. An aliphatic carboxylic acid (e.g., CH(3)COOH) separated by a weakly acidic CEX column of the H(+)-form converts into that of the K(+)-form (e.g., CH(3)COOK) by passing through the enhancer resin. In contrast, the background conductivity decreases because a strong acid (e.g., HNO(3)) with a higher conductimetric response in an eluent converts into a salt (e.g., KNO(3)) with a lower conductimetric response. Since the pH of the eluent containing the resin enhancer increases from 3.27 to 5.85, the enhancer accelerates the dissociations of analyte acids. Consequently, peak heights and peak areas of aliphatic carboxylic acids (e.g., acetic acid, propionic acid, butyric acid, and valeric acid) with the enhancer resin are 6.3-8.0 times higher and 7.2-9.2 times larger, respectively, than those without the enhancer resin. Calibrations of peak areas for injected analytes are linear in the concentration range of 0.01-1.0mM. The detection limits (signal-to-noise ratio=3) range from 0.10 microM to 0.39 microM in this system, as opposed to those in the range of 0.24-7.1 microM in the separation column alone. The developed system is successfully applied to the determination of aliphatic carboxylic acids in a chicken droppings sample. PMID:19615503

  5. Anaerobic Conversion of Lactic Acid to Acetic Acid and 1,2-Propanediol by Lactobacillus buchneri

    Oude Elferink, S.J.W.H.; Krooneman, J.; Gottschal, J.C.; Spoelstra, S F; FABER, F; Driehuis, F

    2001-01-01

    The degradation of lactic acid under anoxic conditions was studied in several strains of Lactobacillus buchneri and in close relatives such as Lactobacillus parabuchneri, Lactobacillus kefir, and Lactobacillus hilgardii. Of these lactobacilli, L. buchneri and L. parabuchneri were able to degrade lactic acid under anoxic conditions, without requiring an external electron acceptor. Each mole of lactic acid was converted into approximately 0.5 mol of acetic acid, 0.5 mol of 1,2-propanediol, and ...

  6. A Clean and Selective Radical Homocoupling Employing Carboxylic Acids with Titania Photoredox Catalysis

    Manley, David W; Walton, John C

    2014-01-01

    A titania photoredox catalysis protocol was developed for the homocoupling of C-centered radicals derived from carboxylic acids. Intermolecular reactions were generally efficient and selective, furnishing the desired dimers in good yields under mild neutral conditions. Selective cross-coupling with two acids proved unsuccessful. An intramolecular adaptation enabled macrocycles to be prepared, albeit in modest yields.

  7. Oxidation of indole-3-acetic acid to oxindole-3-acetic acid by etiolated and green corn tissues

    Etiolated corn tissues oxidase indole-3-acetic acid (IAA) to oxindole-3-acetic acid (OxIAA). This oxidation results in loss of auxin activity and may plant a role in regulating IAA-stimulated growth. The enzyme has been partially purified and characterized and shown to require O2, and a heat-stable lipid-soluble corn factor which can be replaced by linolenic or linoleic acids in the oxidation of IAA. Corn oil was tested as a cofactor in the IAA oxidation reaction. Corn oil stimulated enzyme activity by 30% while trilinolein was inactive. The capacity of green tissue to oxidize IAA was examined by incubating leaf sections from 2 week old light-grown corn seedlings with 14C-IAA. OxIAA and IAA were separated from other IAA metabolites on a 3 ml anion exchange column. Of the IAA taken up by the sections, 13% was oxidized to OxIAA. This is the first evidence that green tissue of corn may also regulate IAA levels by oxidizing IAA to OxIAA

  8. Selenium dioxide catalysed oxidation of acetic acid hydrazide by bromate in aqueous hydrochloric acid medium

    R S Yalgudre; G S Gokavi

    2012-07-01

    Selenium dioxide catalysed acetic acid hydrazide oxidation by bromate was studied in hydrochloric acid medium. The order in oxidant concentration, substrate and catalyst were found to be unity. Increasing hydrogen ion concentration increases the rate of the reaction due to protonation equilibria of the oxidant. The mechanism of the reaction involves prior complex formation between the catalyst and substrate, hydrazide, followed by its oxidation by diprotonated bromate in a slow step. Acetic acid was found to be the oxidation product. Other kinetic data like effect of solvent polarity and ionic strength on the reaction support the proposed mechanism.

  9. Ionic liquid mediated esterification of alcohol with acetic acid

    Beilei ZHOU; Yanxiong FANG; Hao GU; Saidan ZHANG; Baohua HUANG; Kun ZHANG

    2009-01-01

    Highly efficient esterification of alcohols with acetic acid by using a Bransted acidic ionic liquid, i.e., 1-methyl-2-pyrrolidonium hydrogen sulfate ([Hnmp]HSo4), as catalyst has been realized. The turnover numbers (TON) were able to reach up to 11000 and turnover frequency (TOF) was 846. The catalytic system is suitable for the esterification of long chain aliphatic alcohols, benzyl alcohol and cyclohexanol with good yields of esters. The procedure of separating the product and catalyst is simple, and the catalyst could be reused. [Hnmp]HSO4 had much weaker corrosiveness than H2SO4. The corrosive rate of H2SO4 was 400 times more than that of [Hnmp]HSO4 to stainless steel.

  10. Enzymatic hydrolysis and fermentability of corn stover pretreated by lactic acid and/or acetic acid

    Xu, Jian; Thomsen, Mette Hedegaard; Thomsen, Anne Belinda

    2009-01-01

    Four different pretreatments with and without addition of low concentration organic acids were carried out on corn stover at 195 °C for 15 min. The highest xylan recovery of 81.08% was obtained after pretreatment without acid catalyst and the lowest of 58.78% after pretreatment with both acetic and...

  11. Synthesis and Crystal Structure of 4-(4,6-Dimethoxylpyrimidin-2-yl)-3-thiourea Carboxylic Acid Ethyl Ester

    ZHANG Yang; HUANG Jie; SONG Ji-Rong; REN Ying-Hui; XU Kang-Zhen

    2008-01-01

    4-(4,6-Dimethoxyl-pyrimidin-2-yl)-3-thiourea carboxylic acid ethyl ester was synthesized by the reaction of 2-amino-4,6-dimethoxyl pyrimidine,potassium thiocyanate and methyl chloroformate in ethyl acetate.Single crystals suitable for X-ray measurement were obtained by recrystallization with the solvent of dimethyl formamidc at room temperature.The crystal structure was determined by X-ray diffraction analysis.Crystallographic data:C10H14N4O4S,Mr=286.31,monoclinic,space group C2/c with a=2.5309(3),b=0.67682(6),c=1.74237(19)nm,β=114.744(3)°,V=2.7106(5)nm3,Dc=1.403 g/cm3,μ=0.225mm-1,F(000)=1200,Z=8,R=0.0514 and wR=0.1529.

  12. Synthesis and Crystal Structure of 4-(4,6-dimethoxyl -pyrimidin-2-yl)-3-thiourea Carboxylic Acid Methyl Ester

    HUANG Jie; SONG Ji-Rong; REN Ying-Hui; XU Kang-Zhen; MA Hai-Xia

    2006-01-01

    The title compound 4-(4,6-dimethoxylpyrimidin-2-yl)-3-thiourea carboxylic acid methyl ester was synthesized by the reaction of 2-amino-4,6-dimethoxyl pyrimidine, potassium thiocyanate and methyl chloroformate in ethyl acetate. Single crystals suitable for X-ray measurement were obtained by recrystallization with the solvent of dimethyl formamide at the room temperature. The structure was characterized by elemental analysis and IR and determined by X-ray diffraction analysis. Crystallographic data: C9H12N4O4S, Mr = 272.29, monoclinic, space group C2/m with a = 1.6672(3), b = 0.66383(12), c = 1.1617(2) nm, β = 109.275(2)°, V = 1.2136(4) nm3, Dc = 1.490 g/cm3, μ = 0.281 mm-1, F(000) = 568, Z = 4, R1 = 0.0341and wR2 = 0.1042.

  13. Lactobionic and cellobionic acid production profiles of the resting cells of acetic acid bacteria.

    Kiryu, Takaaki; Kiso, Taro; Nakano, Hirofumi; Murakami, Hiromi

    2015-01-01

    Lactobionic acid was produced by acetic acid bacteria to oxidize lactose. Gluconobacter spp. and Gluconacetobacter spp. showed higher lactose-oxidizing activities than Acetobacter spp. Gluconobacter frateurii NBRC3285 produced the highest amount of lactobionic acid per cell, among the strains tested. This bacterium assimilated neither lactose nor lactobionic acid. At high lactose concentration (30%), resting cells of the bacterium showed sufficient oxidizing activity for efficient production of lactobionic acid. These properties may contribute to industrial production of lactobionic acid by the bacterium. The bacterium showed higher oxidizing activity on cellobiose than that on lactose and produced cellobionic acid. PMID:25965080

  14. Asymmetric synthesis of crambescin A-C carboxylic acids and their inhibitory activity on voltage-gated sodium channels.

    Nakazaki, Atsuo; Nakane, Yoshiki; Ishikawa, Yuki; Yotsu-Yamashita, Mari; Nishikawa, Toshio

    2016-06-21

    Synthesis of both enantiomers of crambescin B carboxylic acid is described. A cis-enyne starting material was epoxidized under the conditions of Katsuki asymmetric epoxidation to give 95% ee of the epoxide, which was transformed to crambescin B carboxylic acid via bromocation-triggered cascade cyclization as the key step. Enantiomerically pure crambescin A and C carboxylic acids were also synthesized from the product of the cascade reaction. Structure-activity relationship (SAR) studies against voltage-gated sodium channel (VGSC) inhibition using those synthetic compounds revealed that the natural enantiomer of crambescin B carboxylic acid was most active and comparable to tetrodotoxin, and the unalkylated cyclic guanidinium structure is indispensible, while the carboxylate moiety is not important. The absolute stereochemistry of crambescin A was determined by a comparison of the methyl ester derived from natural crambescin A with that derived from the stereochemically defined crambescin A carboxylic acid synthesized in this study. PMID:27215973

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

    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.

  16. Crystal Structure and Properties of the Carboxylic Acid Derivatives of Schizonpeta mulifida (L.) Briq.

    LIU,Ju-Tao; YU,Ji-Cheng; JIANG,Hui-Ming; ZHANG,Li-Ying; ZHAO,Xiao-Jing; FAN,Sheng-Di

    2008-01-01

    The chemical constituents of the carboxylic acid derivatives from the ear of Schizonepeta were investigated,1H and 13C NMR chemical shifts of the carboxylic acid derivatives were accurately assigned.Two carboxylic acid derivative constituents were separated by a silica gel column.The structures were elucidated by the physical and chemical properties,IR,1H NMR,13C NMR,MALDI-TDF-MS and X-ray single crystal diffractometry.They were identified as 3-imino-N-(a-imidoethylamino)butyrolactam and neononane tetracid,respectively.The antitumoral activity on liver tumor ceils SMMC-7721 was determined in vitro.The experimental results showed that the former was better than the latter,and with increasing the concentration of the former the inhibitory activity was increased.

  17. Extraction of actinide elements by trilaurylammonium nitrate carboxylic acid mixtures and applications

    The addition of pelargonic, capric, α-bromocapric, α-fluorocapric, and 3-fluorobenzoic acids to organic trilaurylammonium nitrate solutions significantly modifies the extraction of U(VI), Np(IV), and Pu(IV). Antagonism appears at strong nitric acidities, while enhancement of the extraction of U(VI) and Pu(IV) is observed at weak acidities. The antagonism observed is due to the formation of addition compounds between trilaurylammonium nitrate (R3NHNO3) and carboxylic acids (HA) = R3NHNO3(HA)2 for pelargonic and capric acids, and R3NHNO3HA for α-bromocapric, α-fluorobenzoic acids. Extraction of UO22+, Am3+, Th4+, Np4+, and Pu4+ by capric, α-bromocapric, and 3-fluorobenzoic acids showed that the extractive power of these carboxylic acids is inadequate for the observation of extraction enhancement. The study of the organic phase by the measurement of nitric acid displacement and by dielectric method shows that trilaurylamine and carboxylic acids react to give the compounds R3N(HA)4 (pelargonic and capric acids) and R3N(HA)2

  18. Study on fluorescence spectra of molecular association of acetic acid-water

    Caiqin Han; Ying Liu; Yang Yang; Xiaowu Ni; Jian Lu; Xiaosen Luo

    2009-01-01

    Fluorescence spectra of acetic acid-water solution excited by ultraviolet (UV) light are studied, and the relationship between fluorescence spectra and molecular association of acetic acid is discussed. The results indicate that when the exciting light wavelength is longer than 246 nm, there are two fluorescence peaks located at 305 and 334 nm, respectively. By measuring the excitation spectra, the optimal wavelengths of the two fluorescence peaks are obtained, which are 258 and 284 nm, respectively. Fluorescence spectra of acetic acid-water solution change with concentrations, which is primarily attributed to changes of molecular association of acetic acid in aqueous solution. Through theoretical analysis, three variations of molecular association have been obtained in acetic acid-water solution, which are the hydrated monomers, the linear dimers, and the water separated dimers. This research can provide references to studies of molecular association of acetic acid-water, especially studies of hydrogen bonds.

  19. Improvement in HPLC separation of acetic acid and levulinic acid in the profiling of biomass hydrolysate.

    Xie, Rui; Tu, Maobing; Wu, Yonnie; Adhikari, Sushil

    2011-04-01

    5-Hydroxymethylfurfural (HMF) and furfural could be separated by the Aminex HPX-87H column chromatography, however, the separation and quantification of acetic acid and levulinic acid in biomass hydrolysate have been difficult with this method. In present study, the HPLC separation of acetic acid and levulinic acid on Aminex HPX-87H column has been investigated by varying column temperature, flow rate, and sulfuric acid content in the mobile phase. The column temperature was found critical in resolving acetic acid and levulinic acid. The resolution for two acids increased dramatically from 0.42 to 1.86 when the column temperature was lowered from 60 to 30 °C. So did the capacity factors for levulinic acid that was increased from 1.20 to 1.44 as the column temperature dropped. The optimum column temperature for the separation was found at 45 °C. Variation in flow rate and sulfuric acid concentration improved not as much as the column temperature did. PMID:21316945

  20. Determination of 13C and 18O isotopic abundances of carboxyl substances; application to amino acids

    Flash pyrolysis of organic acids or of their salts gives off carbon dioxide which can be analysed by mass spectrometry for 13C and 18O abundance. This principle has been applied to Cd13C18O3 using an induction furnace, and used to determine the 13C and 18O content of the carboxylic group of some amino acids. The technique described has many advantages over the classical pyrolysis methods using sealed tubes. It is rapid and simple and especially effective in determining the isotopic composition of hygroscopic carboxyl substances. (U.K.)

  1. Effect of acetic acid on lipid accumulation by glucose-fed activated sludge cultures

    Mondala, Andro; Hernandez, Rafael; French, Todd; McFarland, Linda; Sparks, Darrell; Holmes, William; Haque, Monica

    2012-01-01

    The effect of acetic acid, a lignocellulose hydrolysis by-product, on lipid accumulation by activated sludge cultures grown on glucose was investigated. This was done to assess the possible application of lignocellulose as low-cost and renewable fermentation substrates for biofuel feedstock production. Results: Biomass yield was reduced by around 54% at a 2 g L -1 acetic acid dosage but was increased by around 18% at 10 g L -1 acetic acid dosage relative to the control run. The final gravimetric lipid contents at 2 and 10 g L -1 acetic acid levels were 12.5 + 0.7% and 8.8 + 3.2% w/w, respectively, which were lower than the control (17.8 + 2.8% w/w). However, biodiesel yields from activated sludge grown with acetic acid (5.6 + 0.6% w/w for 2 g L -1 acetic acid and 4.2 + 3.0% w/w for 10 g L -1 acetic acid) were higher than in raw activated sludge (1-2% w/w). The fatty acid profiles of the accumulated lipids were similar with conventional plant oil biodiesel feedstocks. Conclusions: Acetic acid enhanced biomass production by activated sludge at high levels but reduced lipid production. Further studies are needed to enhance acetic acid utilization by activated sludge microorganisms for lipid biosynthesis.

  2. Transcript and metabolite alterations increase ganoderic acid content in Ganoderma lucidum using acetic acid as an inducer.

    Ren, Ang; Li, Xiong-Biao; Miao, Zhi-Gang; Shi, Liang; Jaing, Ai-Liang; Zhao, Ming-Wen

    2014-12-01

    Acetic acid at 5-8 mM increased ganoderic acid (GA) accumulation in Ganoderma lucidum. After optimization by the response surface methodology, the GA content reached 5.5/100 mg dry weight, an increase of 105% compared with the control. The intermediate metabolites of GA biosynthesis, lanosterol and squalene also increased to 47 and 15.8 μg/g dry weight, respectively, in response to acetic acid. Acetic acid significantly induced transcription levels of sqs, lano, hmgs and cyp51 in the GA biosynthesis pathway. An acetic acid-unregulated acetyl coenzyme A synthase (acs) gene was selected from ten candidate homologous acs genes. The results indicate that acetic acid alters the expression of genes related to acetic acid assimilation and increases GA biosynthesis and the metabolic levels of lanosterol, squalene and GA-a, thereby resulting in GA accumulation. PMID:25216642

  3. Recovery of Ammonium Nitrate and Reusable Acetic Acid from Effluent Generated during HMX Production

    V. D. Raut; R. S. Khopade; M. V. Rajopadhye; V. L. Narasimhan

    2004-01-01

    Production of HMX on commercial scale is mainly carried out by modified Bachmann process, and acetic acid constitutes major portion of effluenttspent liquor produced during this process. The recovery of glacial acetic acid from this spent liquor is essential to make the process commercially viable besides making it eco-friendly by minimising the quantity of disposable effluent. The recovery of glacial acetic acid from spent liquor is not advisable by simple distillation since it contains, in ...

  4. Development and validation of a reversed-phase liquid chromatography method for the quantitative determination of carboxylic acids in industrial reaction mixtures.

    Destandau, E; Vial, J; Jardya, A; Henniona, M C; Bonnet, D; Lancelin, P

    2005-09-23

    Usually analysis of low molecular-mass carboxylic acids was performed by anion-exchange or ion-exclusion chromatographic methods. Reversed-phase liquid chromatography (RPLC) was evaluated in this work as an alternative method for the analysis of low molecular-mass aliphatic mono- and di-carboxylic acids (formic, acetic, propionic, butyric, valeric, caproic, succinic, glutaric and adipic) in aqueous media. The separation of the nine organic acids was optimised in 21 min on a high-density C18 column with an elution gradient made up of HClO4 aqueous solution 10(-3) mol L(-1) and acetonitrile. For the quantitation, external standard and standard addition methods were compared. Both methods gave similar results, so the most convenient method, external standard, was chosen for acids quantitation. Then the method had been validated and applied to the semi-quantitative analysis of formic and acetic acids and to the quantitative analysis of the others compounds in industrial reaction mixtures with concentrations ranging from 20 to 570 ppm. PMID:16130732

  5. Development of Acetic Acid Removal Technology for the UREX+Process

    Robert M. Counce; Jack S. Watson

    2009-06-30

    It is imperative that acetic acid is removed from a waste stream in the UREX+process so that nitric acid can be recycled and possible interference with downstreatm steps can be avoidec. Acetic acid arises from acetohydrozamic acid (AHA), and is used to suppress plutonium in the first step of the UREX+process. Later, it is hydrolyzed into hydroxyl amine nitrate and acetic acid. Many common separation technologies were examined, and solvent extraction was determined to be the best choice under process conditions. Solvents already used in the UREX+ process were then tested to determine if they would be sufficient for the removal of acetic acid. The tributyl phosphage (TBP)-dodecane diluent, used in both UREX and NPEX, was determined to be a solvent system that gave sufficient distribution coefficients for acetic acid in addition to a high separation factor from nitric acid.

  6. Development of Acetic Acid Removal Technology for the UREX+Process

    It is imperative that acetic acid is removed from a waste stream in the UREX+process so that nitric acid can be recycled and possible interference with downstream steps can be avoided. Acetic acid arises from acetohydrozamic acid (AHA), and is used to suppress plutonium in the first step of the UREX+process. Later, it is hydrolyzed into hydroxyl amine nitrate and acetic acid. Many common separation technologies were examined, and solvent extraction was determined to be the best choice under process conditions. Solvents already used in the UREX+ process were then tested to determine if they would be sufficient for the removal of acetic acid. The tributyl phosphage (TBP)-dodecane diluent, used in both UREX and NPEX, was determined to be a solvent system that gave sufficient distribution coefficients for acetic acid in addition to a high separation factor from nitric acid

  7. Ozone-driven daytime formation of secondary organic aerosol containing carboxylic acid groups and alkane groups

    S. Liu

    2011-08-01

    Full Text Available Carboxylic acids are present in substantial quantities in atmospheric particles, and they play an important role in the physical and chemical properties of aerosol particles. During measurements in coastal California in the summer of 2009, carboxylic acid functional groups were exclusively associated with a fossil fuel combustion factor derived from factor analysis of Fourier transform infrared spectroscopic measurements and closely correlated with oxygenated organic factors from aerosol mass spectrometry measurements. The high fraction of acid groups and the high ratio of oxygen to carbon in this factor suggest that this factor is composed of secondary organic aerosol (SOA products of combustion emissions from the upwind industrial region (the ports of Los Angeles and Long Beach. Another indication of the photochemically-driven secondary formation of this combustion-emitted organic mass (OM was the daytime increase in the concentrations of acid groups and the combustion factors. This daytime increase closely tracked the O3 mixing ratio with a correlation coefficient of 0.7, indicating O3 was closely associated with the SOA maximum and thus likely the oxidant that resulted in acid group formation. Using a pseudo-Lagrangian framework to interpret this daytime increase of carboxylic acid groups and the combustion factors, we estimate that the carboxylic acid groups formed in a 12-h daytime period of one day ("Today's SOA" accounted for 25–33 % of the measured carboxylic acid group mass, while the remaining 67–75 % (of the carboxylic acid group mass was likely formed 1–3 days previously (the "Background SOA". A similar estimate of the daytime increase in the combustion factors suggests that "Today's SOA" and the "Background SOA" respectively contributed 25–50 % and 50–75 % of the combustion factor (the "Total SOA", for a "Total SOA" contribution to the OM of 60 % for the project average. Further, size

  8. Process for recovering carboxylic acids from sugar cane industry by-products

    Albet, Joël; Pislor, Emilie; Pontalier, Pierre-Yves

    2009-01-01

    Food industry by-products such as molasses and vinasses may provide an important source of organic acids. The aim of this study is to compare three processes, precipitation, chromatography and liquid-liquid extraction, for the recovery of carboxylic acids from sugarcane molasses from Réunion Island. Precipitation was performed with different temperatures by addition of calcium chloride. The results revealed that precipitation can recover aconitic acid efficiently from molasses. Liquid-liquid ...

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

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

    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 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). PMID:26674688

  10. [Removal of tattoos by CO2 laser and acetic acid].

    Di Quirico, R; Pallini, G; Di Domenicantonio, G; Astolfi, A; Bindi, F; Gianfelice, F

    1992-10-31

    The Authors pay attention to small tattoo removal by means of the utilization of the CO2 laser. Moreover, the Authors emphasize the drawback of double treatment which, usually, the patient suffers in tattoo removal by CO2 laser. Then, the pressure of the Authors is small sized tattoo removal in only one sitting achieving so an excellent esthetic result. Besides, the Authors, in this medical study, explains two methods for tattoo removal. In the study's results, the Authors describes the manner and the time of the two lesion recovery by the different manners of treatment. Finally, the Authors affirms the great consequence of the surgical CO2 laser, they don't fail, however, to affirm that the laser and acetic acid combination is an excellent procedure for small tattoo removal. PMID:1480288

  11. Gas-Phase Reactivity of Carboxylic Acid Functional Groups with Carbodiimides

    Prentice, Boone M.; Gilbert, Joshua D.; Stutzman, John R.; Forrest, William P.; McLuckey, Scott A.

    2013-01-01

    Gas-phase modification of carboxylic acid functionalities is performed via ion/ion reactions with carbodiimide reagents [ N-cyclohexyl- N'-(2-morpholinoethyl)carbodiimide (CMC) and [3-(3-Ethylcarbodiimide-1-yl)propyl]trimethylaminium (ECPT)]. Gas-phase ion/ion covalent chemistry requires the formation of a long-lived complex. In this instance, the complex is stabilized by an electrostatic interaction between the fixed charge quaternary ammonium group of the carbodiimide reagent cation and the analyte dianion. Subsequent activation results in characteristic loss of an isocyanate derivative from one side of the carbodiimide functionality, a signature for this covalent chemistry. The resulting amide bond is formed on the analyte at the site of the original carboxylic acid. Reactions involving analytes that do not contain available carboxylic acid groups (e.g., they have been converted to sodium salts) or reagents that do not have the carbodiimide functionality do not undergo a covalent reaction. This chemistry is demonstrated using PAMAM generation 0.5 dendrimer, ethylenediaminetetraacetic acid (EDTA), and the model peptide DGAILDGAILD. This work demonstrates the selective gas-phase covalent modification of carboxylic acid functionalities.

  12. Templating route for mesostructured calcium phosphates with carboxylic acid- and amine-type surfactants.

    Ikawa, Nobuaki; Hori, Hideki; Kimura, Tatsuo; Oumi, Yasunori; Sano, Tsuneji

    2008-11-18

    Mesostructured calcium phosphates constructed by ionic frameworks were synthesized using carboxylic acid- and amine-type surfactants in mixed solvent systems of ethanol and water. A lamellar mesostructured calcium phosphate was prepared using palmitic acid as an anionic surfactant, as in the case using n-alkylamines. A wormhole-like mesostructured calcium phosphate can be obtained using dicarboxyl N-lauroyl- l-glutamic acid, whose headgroup is larger than that of palmitic acid. Similar mesostructured product was obtained using 4-dodecyldiethylenetriamine with a large headgroup containing two primary amine groups. Interactions of carboxyl and primary amino groups in the surfactant molecules with inorganic species are quite important for the formation of mesostructured calcium phosphates. The Ca/P molar ratio of mesostructured calcium phosphates was strongly affected by the molecular structure of surfactants containing carboxyl and primary amino groups. Ca-rich materials can be obtained using carboxylic acid-type surfactants (Ca/P approximately 1.7) rather than amine-type surfactants (Ca/P approximately 1.0). PMID:18947246

  13. Detection of CIN by naked eye visualization after application of acetic acid.

    Londhe, M; George, S S; Seshadri, L

    1997-06-01

    A prospective study was undertaken to determine the sensitivity and specificity of acetic application to the cervix followed by naked eye visualization as a screening test for detection of cervical intraepithelial neoplasia. Three hundred and seventy two sexually active woman in the reproductive age group were studied. All the women underwent Papanicolaou test, acetic acid test and colposcopy. One hundred and seventy five woman were acetic acid test negative, 197 women were acetic acid test positive. The sensitivity of acetic acid test was 72.4%, specificity 54% and false negative rate 15.2%, as compared to papanicolaou test which had a sensitivity of 13.2%, specificity of 96.3% and false negative rate of 24.4%. The advantage of the acetic acid test lies in its easy technique, low cost and high sensitivity which are important factors for determining the efficacy of any screening programme in developing countries. PMID:9491668

  14. Inflammatory cells′ role in acetic acid-induced colitis

    Mohammad H Sanei

    2014-01-01

    Full Text Available Background: Free radicals are the known mechanisms responsible for inducing colitis with two origins: Inflammatory cells and tissues. Only the inflammatory cells can be controlled by corticosteroids. Our aim was to assess the importance of neutrophils as one of the inflammatory cells in inducing colitis and to evaluate the efficacy of corticosteroids in the treatment of inflammatory bowel disease (IBD. Materials and Methods: Thirty-six mice were divided into six groups of six mice each. Colitis was induced in three groups by exposing them to acetic acid through enema (group 1, ex vivo (group 3, and enema after immune suppression (group 5. Each group had one control group that was exposed to water injection instead of acetic acid. Tissue samples were evaluated and compared based on macroscopic damages and biochemical and pathological results. Results: Considering neutrophilic infiltration, there were significant differences between groups 1, 3, 5, and the control of group 1. Groups 3, 5, and their controls, and group 1 and the control of group 3 had significant differences in terms of goblet depletion. Based on tissue originated H 2 O 2 , we found significant differences between group 1 and its control and group 3, and also between groups 5 and the control of group 3. All the three groups were significantly different from their controls based on Ferric Reducing Ability of Plasma (FRAP and such differences were also seen between group 1 with two other groups. Conclusion: Neutrophils may not be the only cause of oxidation process in colitis, and also makes the effectiveness of corticosteroids in the treatment of this disease doubtful.

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

    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, 1H-and 13C- 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)

  16. Significant improvement in the pore properties of SBA-15 brought about by carboxylic acids and hydrothermal treatment

    Milan Kanti Naskar; M Eswaramoorthy

    2008-01-01

    A comparative study of the pore properties of SBA-15 samples prepared under nonhydrothermal and hydrothermal conditions, in the absence and presence of carboxylic acids such as succinic, tartaric and citric acids has been carried out. In the absence of carboxylic acid, flake-like and spheroid particles were generally obtained irrespective of the preparative procedures. On the other hand, stirring of the pre-mix induces a rod-like morphology in presence of carboxylic acids. The samples prepared under non-hydrothermal conditions exhibit a higher degree of silicate condensation compared to those synthesized under hydrothermal conditions. SBA-15 samples prepared under hydrothermal conditions show higher values of the d (100) spacing independent of the presence of carboxylic acids. Presence of carboxylic acids as well as hydrothermal treatment improves the pore properties of SBA-15.

  17. Z-effect reversal in carboxylic acid associates.

    Medvedev, Michael G; Bushmarinov, Ivan S; Lyssenko, Konstantin A

    2016-05-01

    The carboxylic group is a common fragment in synthetic compounds and biomolecules. Its conformation is assumed to be dominantly cis due to so-called Z-effect. However, in this study, we show that the nature of the H-bond acceptor in RCOOHX directly affects the conformational preference of the resulting supermolecule. This result is evident from the statistical analysis of available crystallographic data and was quantified using accurate quantum chemical calculations. We propose the term "supramolecular stereoelectronic effect" for the observed conformational preference. The likely reason for this is the interaction of the O-HX hydrogen bond with the C[double bond, length as m-dash]O double bond in the trans conformation, which in case of anionic X is strong enough to reverse the Z-effect. Explicit consideration of trans COOHX stabilization can help crystal structure predictions and biomolecular simulations. In particular, this effect plays a key role in the transition between the T6 and R6 forms of human insulin. PMID:27109148

  18. Isolation, characterization and optimization of indigenous acetic acid bacteria and evaluation of their preservation methods

    K Beheshti-Maal

    2010-06-01

    Full Text Available Background and Objectives: Acetic acid bacteria (AAB are useful in industrial production of vinegar. The present study aims at isolation and identification of acetic acid bacteria with characterization, optimization, and evaluation of their acetic acid productivity."nMaterials and Methods: Samples from various fruits were screened for presence of acetic acid bacteria on glucose, yeast extract, calcium carbonate (GYC medium. Carr medium supplemented with bromocresol green was used for distinguishing Acetobacter from Gluconobacter. The isolates were cultured in basal medium to find the highest acetic acid producer. Biochemical tests followed by 16S rRNA and restriction analyses were employed for identification of the isolate and phylogenic tree was constructed. Bacterial growth and acid production conditions were optimized based on optimal inoculum size, pH, temperature, agitation, aeration and medium composition."nResults: Thirty-seven acetic acid bacteria from acetobacter and gluconobacter members were isolated. Acetic acid productivity yielded 4 isolates that produced higher amounts of acid. The highest producer of acid (10.03% was selected for identification. The sequencing and restriction analyses of 16S rRNA revealed a divergent strain of Acetobacter pasteurianus (Gene bank accession number # GU059865. The optimum condition for acid production was a medium composed of 2% glucose, 2% yeast extract, 3% ethanol and 3% acid acetic at inoculum size of 4% at 3L/Min aeration level in the production medium. The isolate was best preserved in GYC medium at 12oC for more than a month. Longer preservation was possible at -70oC."nConclusion: The results are suggestive of isolation of an indigenous acetic acid bacteria. Pilot plan is suggested to study applicability of the isolated strain in acetic acid production.

  19. Multilayer Film Fabrication and Photoelectric Conversion Property of Two Pyrrolidinofullerene Carboxylic Acid Derivatives

    2000-01-01

    Two multilayer films of pyrrolidinofullerene carboxylic acid derivatives, which exhibit photoelectric conversion property, are reported here. The first monolayers were fabricated on hydrophilic indium-tin-oxide (ITO), quartz, and mica by esterification reaction. The multilayers were characterized by contact angle and UV spectrum. The photoelectric conversion properties of both multilayer films were studied.

  20. Ionic liquids as solvent for efficient esterification of carboxylic acids with alkyl halides

    carboxylic, Ionic liquids as solvent for efficient e

    2010-01-01

    The selective esterification of carboxylic acid derivatives with a variety of alkyl halides was carried out using ionic liquid as solvent in the presence of triethylamine. The reaction was found to proceed under relatively mild conditions with excellent conversions (up to 99%) and selectivities. The ionic liquid was recycled and reused.

  1. Acyl Radicals from Aromatic Carboxylic Acids by Means of Visible-Light Photoredox Catalysis

    Bergonzini, Giulia; Cassani, Carlo; Wallentin, Carl-Johan

    2015-01-01

    Simple and abundant carboxylic acids have been used as acyl radical precursor by means of visible-light photoredox catalysis. By the transient generation of a reactive anhydride intermediate, this redox-neutral approach offers a mild and rapid entry to high-value heterocyclic compounds without the need of UV irradiation, high temperature, high CO pressure, tin reagents, or peroxides.

  2. Kinetics of the esterification of active pharmaceutical ingredients containing carboxylic Acid functionality in polyethylene glycol

    Schou-Pedersen, Anne Marie V; Hansen, Steen Honoré; Moesgaard, Birthe;

    2014-01-01

    reactions. In this study, kinetics of two active pharmaceutical ingredients, cetirizine and indomethacin possessing carboxylic acid functionality, has been studied in PEG 400 and PEG 1000 at 50°C, 60°C, 70°C, and 80°C. HPLC-UV was applied for the determination of concentrations in the kinetic studies...

  3. ANTI-CORROSION PROPERTIES OF CARBOXYLIC ACID IN WATER-GLYCOL SOLUTIONS

    BASHKIRCEVA N.Y.

    2012-01-01

    Full Text Available Sodium salts of carboxylic acids were investigated to evaluate the corrosion properties of the water-glycol solutions. Corrosion tests were performed by methods of gravimetry and galvanostatic dissolution with metals used in cooling systems. The compositions of anticorrosion systems and their concentration that provide the most effective inhibition of metals were determined.

  4. Iron-catalyzed decarboxylative alkenylation of cycloalkanes with arylvinyl carboxylic acids via a radical process

    Jiancan Zhao

    2013-08-01

    Full Text Available A Fe(acac3-catalyzed decarboxylative coupling of 2-(arylvinyl carboxylic acids with cycloalkanes was developed by using DTBP as an oxidant through a radical process. This reaction tolerates a wide range of substrates, and products are obtained in good to excellent yields (71–95%. The reaction also shows excellent stereoselectivity, and only trans-isomers are obtained.

  5. Iron-catalyzed decarboxylative alkenylation of cycloalkanes with arylvinyl carboxylic acids via a radical process

    Jiancan Zhao; Hong Fang; Jianlin Han; Yi Pan

    2013-01-01

    A Fe(acac)3-catalyzed decarboxylative coupling of 2-(aryl)vinyl carboxylic acids with cycloalkanes was developed by using DTBP as an oxidant through a radical process. This reaction tolerates a wide range of substrates, and products are obtained in good to excellent yields (71–95%). The reaction also shows excellent stereoselectivity, and only trans-isomers are obtained.

  6. Iron-catalyzed decarboxylative alkenylation of cycloalkanes with arylvinyl carboxylic acids via a radical process.

    Zhao, Jiancan; Fang, Hong; Han, Jianlin; Pan, Yi

    2013-01-01

    A Fe(acac)3-catalyzed decarboxylative coupling of 2-(aryl)vinyl carboxylic acids with cycloalkanes was developed by using DTBP as an oxidant through a radical process. This reaction tolerates a wide range of substrates, and products are obtained in good to excellent yields (71-95%). The reaction also shows excellent stereoselectivity, and only trans-isomers are obtained. PMID:24062833

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

    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.

  8. Recovery of Ammonium Nitrate and Reusable Acetic Acid from Effluent Generated during HMX Production

    V. D. Raut

    2004-04-01

    Full Text Available Production of HMX on commercial scale is mainly carried out by modified Bachmann process, and acetic acid constitutes major portion of effluenttspent liquor produced during this process. The recovery of glacial acetic acid from this spent liquor is essential to make the process commercially viable besides making it eco-friendly by minimising the quantity of disposable effluent. The recovery of glacial acetic acid from spent liquor is not advisable by simple distillation since it contains, in addition to acetic acid, a small fraction of nitric acid, traces of RDX, HMX, and undesired nitro compounds. The process normally involves neutralising the spent mother liquor with liquor ammonia and then distillating the ueutralised mother liquor under vacuum to recover dilute acetic acid (strength approx. 30 %. The dilute acetic acid, in turn, is concentrated to glacial acetic acid by counter current solvent extraction, followed by distillation. The process is very lengthy and the energy requirement is also veryhigh, rendering the process economically unviable. Hence, a novel method has been developed on bench-scale to obtain glacial acetic acid directly from the mother liquor after the second ageing process.

  9. Progress in Acetic Acid Industry%醋酸工业现状及发展

    李好管; 闫慧芳

    2001-01-01

    醋酸是用途最广泛的有机酸之一。分析了醋酸的生产和消费趋势;综述了醋酸工艺的进展;介绍了具有工业化前景或学术价值的醋酸合成新工艺的研究开发概况。对我国醋酸工业发展提出了建议。%Acetic acid is one of the organic acids which have many uses.This paper analyzed the production and consumption of acetic acid,summarized the progress of acetic acid technology,introduced the research and development of acetic acid new process.Some suggestions on China's acetic acid industry were also put forward.

  10. (±)-trans-3-Benzoyl-bicyclo-[2.2.2]octane-2-carboxylic acid.

    Lalancette, Roger A; Thompson, Hugh W; Brunskill, Andrew P J

    2008-01-01

    The title keto acid, C(16)H(18)O(3), displays significant twisting of all three ethyl-ene bridges in its bicyclo-[2.2.2]octane structure owing to steric inter-actions; the bridgehead-to-bridgehead torsion angles are 13.14 (12), 13.14 (13) and 9.37 (13)°. The compound crystallizes as centrosymmetric carboxyl dimers [O⋯O = 2.6513 (12) Å and O-H⋯O = 178°], which have two orientations within the cell and contain no significant carboxyl disorder. PMID:21201657

  11. (±-trans-3-Benzoylbicyclo[2.2.2]octane-2-carboxylic acid

    Andrew P. J. Brunskill

    2008-09-01

    Full Text Available The title keto acid, C16H18O3, displays significant twisting of all three ethylene bridges in its bicyclo[2.2.2]octane structure owing to steric interactions; the bridgehead-to-bridgehead torsion angles are 13.14 (12, 13.14 (13 and 9.37 (13°. The compound crystallizes as centrosymmetric carboxyl dimers [O...O = 2.6513 (12 Å and O—H...O = 178°], which have two orientations within the cell and contain no significant carboxyl disorder.

  12. 5,6-dihydroxyindole-2-carboxylic acid (DHICA): a First Principles Density-Functional Study

    Powell, B J

    2016-01-01

    We report first principles density functional calculations for 5,6-dihydroxyindole-2-carboxylic acid (DHICA) and several reduced forms. DHICA and 5,6-dihydroxyindole (DHI) are believed to be the basic building blocks of the eumelanins. Our results show that carboxylation has a significant effect on the physical properties of the molecules. In particular, the relative stabilities and the HOMO-LUMO gaps (calculated with the $\\Delta$SCF method) of the various redox forms are strongly affected. We predict that, in contrast to DHI, the density of unpaired electrons, and hence the ESR signal, in DHICA is negligibly small.

  13. Factors influencing the rate of non-enzymatic activation of carboxylic and amino acids by ATP

    Mullins, D. W., Jr.; Lacey, J. C., Jr.

    1981-01-01

    The nonenzymatic formation of adenylate anhydrides of carboxylic and amino acids is discussed as a necessary step in the origin of the genetic code and protein biosynthesis. Results of studies are presented which have shown the rate of activation to depend on the pKa of the carboxyl group, the pH of the medium, temperature, the divalent metal ion catalyst, salt concentration, and the nature of the amino acid. In particular, it was found that of the various amino acids investigated, phenylalanine had the greatest affinity for the adenine derivatives adenosine and ATP. Results thus indicate that selective affinities between amino acids and nucleotides were important during prebiotic chemical evolution, and may have played a major role in the origin of protein synthesis and genetic coding.

  14. Carboxylic acid reductase is a versatile enzyme for the conversion of fatty acids into fuels and chemical commodities

    Akhtar, M. K.; Turner, N. J.; Jones, P R

    2012-01-01

    Aliphatic hydrocarbons such as fatty alcohols and petroleum-derived alkanes have numerous applications in the chemical industry. In recent years, the renewable synthesis of aliphatic hydrocarbons has been made possible by engineering microbes to overaccumulate fatty acids. However, to generate end products with the desired physicochemical properties (e.g., fatty aldehydes, alkanes, and alcohols), further conversion of the fatty acid is necessary. A carboxylic acid reductase (CAR) from Mycobac...

  15. Density Functional Theory Study on the Interactions of Metal Ions with Long Chain Deprotonated Carboxylic Acids.

    Mehandzhiyski, Aleksandar Y; Riccardi, Enrico; van Erp, Titus S; Koch, Henrik; Åstrand, Per-Olof; Trinh, Thuat T; Grimes, Brian A

    2015-10-01

    In this work, interactions between carboxylate ions and calcium or sodium ions are investigated via density functional theory (DFT). Despite the ubiquitous presence of these interactions in natural and industrial chemical processes, few DFT studies on these systems exist in the literature. Special focus has been placed on determining the influence of the multibody interactions (with up to 4 carboxylates and one metal ion) on an effective pair-interaction potential, such as those used in molecular mechanics (MM). Specifically, DFT calculations are employed to quantify an effective pair-potential that implicitly includes multibody interactions to construct potential energy curves for carboxylate-metal ion pairs. The DFT calculated potential curves are compared to a widely used molecular mechanics force field (OPLS-AA). The calculations indicate that multibody effects do influence the energetic behavior of these ionic pairs and the extent of this influence is determined by a balance between (a) charge transfer from the carboxylate to the metal ions which stabilizes the complex and (b) repulsion between carboxylates, which destabilizes the complex. Additionally, the potential curves of the complexes with 1 and 2 carboxylates and one counterion have been examined to higher separation distance (20 Å) by the use of relaxed scan optimization and constrained density functional theory (CDFT). The results from the relaxed scan optimization indicate that near the equilibrium distance, the charge transfer between the metal ion and the deprotonated carboxylic acid group is significant and leads to non-negligible differences between the DFT and MM potential curves, especially for calcium. However, at longer separation distances the MM calculated interaction potential functions converge to those calculated with CDFT, effectively indicating the approximate domain of the separation distance coordinate where charge transfer between the ions is occurring. PMID:26331433

  16. Structure–anticancer activity relationships among 4-azolidinone-3-carboxylic acids derivatives

    Lesyk R. B.; Kaminskyy D. V.

    2010-01-01

    The aim of present research was investigation of anticancer activity of 4-azolidinone-3-carboxylic acids derivatives, and studies of structure–activity relationships (SAR) aspects. Methods. Organic synthesis; spectral methods; anticancer screening was performed according to the US NCI protocol (Developmental Therapeutic Program). Results. The data of new 4-thiazolidinone-3-alkanecarboxylic acids derivatives in vitro anticancer activity were described. The most active compounds which belong to...

  17. A novel application of horseradish peroxidase: Oxidation of alcohol ethoxylate to alkylether carboxylic acid

    2008-01-01

    A novel application of horseradish peroxidase (HRP) in the oxidation of alcohol ethoxylate to alkylether carboxylie acid in the present of H2O2 was reported in this paper. We propose the mechanism for the catalytic oxidation reaction is that the hydrogen transfers from the substrate to the ferryl oxygen to form the a-hydroxy carbon radical intermediate. The reaction offers a new approach for further research structure and catalytic mechanism of HRP and production of alkylether carboxylic acid.

  18. Understanding Potential Exposure Sources of Perfluorinated Carboxylic Acids in the Workplace

    Kaiser, Mary A.; Dawson, Barbara J.; Barton, Catherine A.; Botelho, Miguel A.

    2010-01-01

    This paper integrates perspectives from analytical chemistry, environmental engineering, and industrial hygiene to better understand how workers may be exposed to perfluorinated carboxylic acids when handling them in the workplace in order to identify appropriate exposure controls. Due to the dramatic difference in physical properties of the protonated acid form and the anionic form, this family of chemicals provides unique industrial hygiene challenges. Workplace monitoring, experimental dat...

  19. Sm(II)-Mediated Electron Transfer to Carboxylic Acid Derivatives: Development of Complexity-Generating Cascades.

    Just-Baringo, Xavier; Procter, David J

    2015-05-19

    Reductive electron transfer (ET) to organic compounds is a powerful method for the activation of substrates via the formation of radicals, radical anions, anions, and dianions that can be exploited in bond-cleaving and bond-forming processes. Since its introduction to the synthetic community in 1977 by Kagan, SmI2 has become one of the most important reducing agents available in the laboratory. Despite its widespread application in aldehyde and ketone reduction, it was widely accepted that carboxylic acid derivatives could not be reduced by SmI2; only recently has our work led to this dogma being overturned, and the reduction of carboxylic acid derivatives using SmI2 can now take its place alongside aldehyde/ketone reduction as a powerful activation mode for synthesis. In this Account, we set out our studies of the reduction of carboxylic acid derivatives using SmI2, SmI2-H2O, and SmI2-H2O-NR3 and the exploitation of the unusual radical anions that are now accessible in unprecedented carbon-carbon bond-forming processes. The Account begins with our serendipitous discovery that SmI2 mixed with H2O is able to reduce six-membered lactones to diols, a transformation previously thought to be impossible. After the successful development of selective monoreductions of Meldrum's acid and barbituric acid heterocyclic feedstocks, we then identified the SmI2-H2O-NR3 reagent system for the efficient reduction of a range of acyclic carboxylic acid derivatives that typically present a significant challenge for ET reductants. Mechanistic studies have led us to propose a common mechanism for the reduction of carboxylic acid derivatives using Sm(II), with only subtle changes observed as the carboxylic acid derivative and Sm(II) reagent system are varied. At the center of our postulated mechanism is the proposed reversibility of the first ET to the carbonyl of carboxylic acid derivatives, and this led us to devise several strategies that allow the radical anion intermediates to be

  20. Cervical cancer risk factors and feasibility of visual inspection with acetic acid screening in Sudan

    Ibrahim, Ahmed; Rasch, Vibeke; Pukkala, Eero;

    2011-01-01

    To assess the risk factors of cervical cancer and the feasibility and acceptability of a visual inspection with acetic acid (VIA) screening method in a primary health center in Khartoum, Sudan.......To assess the risk factors of cervical cancer and the feasibility and acceptability of a visual inspection with acetic acid (VIA) screening method in a primary health center in Khartoum, Sudan....

  1. Efficacy of Acetic Acid against Listeria monocytogenes Attached to Poultry Skin during Refrigerated Storage

    Elena Gonzalez-Fandos

    2014-09-01

    Full Text Available This work evaluates the effect of acetic acid dipping on the growth of L. monocytogenes on poultry legs stored at 4 °C for eight days. Fresh inoculated chicken legs were dipped into either a 1% or 2% acetic acid solution (v/v or distilled water (control. Changes in mesophiles, psychrotrophs, Enterobacteriaceae counts and sensorial characteristics (odor, color, texture and overall appearance were also evaluated. The shelf life of the samples washed with acetic acid was extended by at least two days over the control samples washed with distilled water. L. monocytogenes counts before decontamination were 5.57 log UFC/g, and after treatment with 2% acetic acid (Day 0, L. monocytogenes counts were 4.47 log UFC/g. Legs washed with 2% acetic acid showed a significant (p < 0.05 inhibitory effect on L. monocytogenes compared to control legs, with a decrease of about 1.31 log units after eight days of storage. Sensory quality was not adversely affected by acetic acid. This study demonstrates that while acetic acid did reduce populations of L. monocytogenes on meat, it did not completely inactivate the pathogen. The application of acetic acid may be used as an additional hurdle contributing to extend the shelf life of raw poultry and reducing populations of L. monocytogenes.

  2. Investigation of acetic acid-catalyzed hydrothermal pretreatment on corn stover

    Xu, Jian; Thomsen, Mette Hedegaard; Thomsen, Anne Belinda

    2010-01-01

    Acetic acid (AA)-catalyzed liquid hot water (LHW) pretreatments on raw corn stover (RCS) were carried out at 195 °C at 15 min with the acetic acid concentrations between 0 and 400 g/kg RCS. After pretreatment, the liquor fractions and water-insoluble solids (WIS) were collected separately and...

  3. Fabrication of First Chinese Made Reactor for Oxosvnthesis of Acetic Acid in Xi'an

    2008-01-01

    @@ The first set of Chinese made reactor for oxo-synthesis of acetic acid has been fabricated by the Xi'an Nuclear Equipment Company,Ltd.This reactor has been transported to the site of equipment installation at the acetic acid production project owned by Shandong Yimeng Company,Ltd.,which has shattered the long-time precedent of relying upon imported equipment.

  4. Dissolution kinetics of nickel ferrite in amino poly carboxylic acids

    Nickel ferrite is one of the important corrosion products of PHWR's where Monel and carbon steel are used as the constructional materials in the primary heat transport system. The dissolution of synthetically prepared nickel ferrite was studied in low concentrations (< 10 mmol/l) of HEDTA, DTPA, NTA and HIDA. The dependence of the dissolution rate on the ligand concentration was found to be langmuirian in all these cases. The effect of the addition of low concentrations of citric acid, oxalic acid, ascorbic acid and Fe(II)-ligand complex, individually, to each of the above chelating agents was also studied. The effect of pH and temperature on the dissolution rate was determined. (author)

  5. A new titanium biofunctionalized interface based on poly(pyrrole-3-acetic acid) coating: proliferation of osteoblast-like cells and future perspectives.

    De Giglio, Elvira; Cometa, Stefania; Calvano, Cosima-Damiana; Sabbatini, Luigia; Zambonin, Pier Giorgio; Colucci, Silvia; Benedetto, Adriana Di; Colaianni, Graziana

    2007-09-01

    In recent years, many procedures based on surface modification have been suggested to improve the biocompatibility and biofunctionality of orthopedic titanium-based implants. In this contest, the development of a new titanium-based biomaterial that could be covalently modified with biologically active molecules (i.e., RGD-peptides, growth factors, etc.) able to improve osteoblasts response was investigated. The strategy followed was based on a preliminary coating of the implant material by an adherent thin polymer film to which bioactive molecules could be grafted exploiting the polymer surface chemical reactivity. In this work, we focused our attention on pyrrole-3-acetic acid (Py-3-acetic), a pyrrole with carboxylic acid substituent, whose electrosynthesis and characterization on titanium substrates were already accomplished and whose potentialities in the design of new biocompatible surfaces are well evident. As first step, the biocompatibility of the electrochemically grown PPy-3-acetic films was investigated performing in vitro tests (adhesion and proliferation) with mouse bone marrow cells. Successively, the availability and reactivity of surface carboxylic groups were tested through the grafting of an aminoacidic residue to PPy-3-acetic films. PMID:17483896

  6. Synthesis of acetic acid via methanol hydrocarboxylation with CO2 and H2.

    Qian, Qingli; Zhang, Jingjing; Cui, Meng; Han, Buxing

    2016-01-01

    Acetic acid is an important bulk chemical that is currently produced via methanol carbonylation using fossil based CO. Synthesis of acetic acid from the renewable and cheap CO2 is of great importance, but state of the art routes encounter difficulties, especially in reaction selectivity and activity. Here we report a route to produce acetic acid from CO2, methanol and H2. The reaction can be efficiently catalysed by Ru-Rh bimetallic catalyst using imidazole as the ligand and LiI as the promoter in 1,3-dimethyl-2-imidazolidinone (DMI) solvent. It is confirmed that methanol is hydrocarboxylated into acetic acid by CO2 and H2, which accounts for the outstanding reaction results. The reaction mechanism is proposed based on the control experiments. The strategy opens a new way for acetic acid production and CO2 transformation, and represents a significant progress in synthetic chemistry. PMID:27165850

  7. Recovery of Dilute Acetic Acid by Catalytic Distillation Using NKC-9 as Catalyst

    ZHANG Zhigang; LI Xiaofeng; XU Shimin; LI Xingang

    2006-01-01

    The reaction kinetics of dilute acetic acid with methanol using NKC-9 as catalyst was studied at temperatures of 308 K, 318 K, 323 K, 328 K. The kinetic model based on Langmuir-Hinshelwood rate model was derived and the activation energy was 6.13 x 104 kJ/kmol. The experiment of recovery of dilute acetic acid was conducted in a packed bed catalytic distillation column. The optimal process parameters and operational conditions determined to make up to 85.9% conversion of acetic acid are as follows:the height of catalyst bed is 1 100 mm, reflux ratio is 4: 1, and the ratio of methanol to acetic acid is 2: 1. The method can be used as a guide in industrial scale recovery of 15%-30% dilute acetic acid.

  8. ANALYSIS OF AIRBORNE CARBOXYLIC ACIDS AND PHENOLS AS THEIR PENTAFLUOROBENZYL DERIVATIVES: GAS CHROMATOGRAPHY/ION TRAP MASS SPECTROMETRY WITH A NOVEL CHEMICAL IONIZATION REAGENT, PFBOH. (R826247)

    The complex photochemical transformations of biogenichydrocarbons such as isoprene and of anthropogenichydrocarbons such as aromatics are an important sourceof carboxylic acids in the troposphere. Theidentificationof unknown carboxylic acids can be difficul...

  9. Kinetics of reaction between acetic acid and Ag2+ in nitric acid medium

    The reaction kinetics between acetic acid and Ag2+ in nitric acid medium is studied by spectrophotometry. The effects of concentrations of acetic acid (HAc), H+, NO3- and temperature on the reaction are investigated. The rate equation has been determined to be -dc(Ag2+)/dt=kc(Ag2+)c(HAc)c-1(H+), where k = (610±15) (mol/L)-1·min-1 with an activation energy of about (48.8±3.5) kJ·mol-1 when the temperature is 25degC and the ionic strength is 4.0 mol/L. The reduction rate of Ag2+ increases with the increase of HAc concentration or temperature and the decrease of HNO3 concentration. However, the effect of NO3- concentrations on the reaction rate is negligible. (author)

  10. Arginine-responsive terbium luminescent hybrid sensors triggered by two crown ether carboxylic acids

    Crown ether carboxylic acids constitute main building blocks for the synthesis of terbium containing covalent cross-linked luminescent materials. Both the complexes and the hybrid nanomaterials could exhibit remarkable green emissions in pure water. More importantly, they were found to have a profound effect on the luminescence responses to arginine compared with glutamic acid, histidine, tryptophan, threonine, tyrosine and phenylalanine in aqueous environment. The present study provided the possibility of using a host–guest mechanism as a way of signal transduction based on lanthanide supramolecular hybrid materials. - Highlights: • Crown ether carboxylic acids were found to sensitize terbium ions among a group of ethers. • The complexes and silica hybrid materials were both prepared and characterized. • They could exhibit remarkable green emissions in pure water