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Sample records for aromatic organic compounds

  1. Alkylation of organic aromatic compounds

    DOEpatents

    Smith, L.A. Jr.

    1989-07-18

    Aromatic compounds are alkylated in a catalytic distillation, wherein the catalyst structure also serves as a distillation component by contacting the aromatic compound with a C[sub 2] to C[sub 10] olefin in the catalyst bed under 0.25 to 50 atmospheres of pressure and at temperatures in the range of 80 C to 500 C, using as the catalyst a mole sieve characterized as acidic or an acidic cation exchange resin. For example, ethyl benzene is produced by feeding ethylene below the catalyst bed while benzene is conveniently added through the reflux in molar excess to that required to react with ethylene, thereby reacting substantially all of the ethylene and recovering benzene as the principal overhead and ethyl benzene in the bottoms. 1 fig.

  2. Alkylation of organic aromatic compounds

    DOEpatents

    Smith, Jr., Lawrence A.; Arganbright, Robert P.; Hearn, Dennis

    1994-01-01

    Aromatic compounds are alkylated in a catalytic distillation, wherein the catalyst structure also serves as a distillation component by contacting the aromatic compound with a C.sub.2 to C.sub.10 olefin in the catalyst bed under 0.25 to 50 atmospheres of pressure and at temperatures in the range of 80.degree. C. to 500.degree. C., using as the catalyst a mole sieve characterized as acidic or an acidic cation exchange resin. For example, ethyl benzene is produced by feeding ethylene below the catalyst bed while benzene is conveniently added through the reflux in molar excess to that required to react with ethylene, thereby reacting substantially all of the ethylene and recovering benzene as the principal overhead and ethyl benzene in the bottoms.

  3. Alkylation of organic aromatic compounds

    DOEpatents

    Smith, L.A. Jr.; Arganbright, R.P.; Hearn, D.

    1993-09-07

    Aromatic compounds are alkylated in a catalytic distillation, wherein the catalyst structure also serves as a distillation component by contacting the aromatic compound with a C[sub 2] to C[sub 10] olefin in the catalyst bed under 0.25 to 50 atmospheres of pressure and at temperatures in the range of 80 C to 500 C, using as the catalyst a molecular sieve characterized as acidic or an acidic cation exchange resin. For example, ethyl benzene is produced by feeding ethylene to about the mid point of the catalyst bed while benzene is conveniently added through the reflux in molar excess to that required to react with ethylene, thereby reacting substantially all of the ethylene and recovering benzene as the principal overhead and ethyl benzene in the bottoms. 1 figures.

  4. Alkylation of organic aromatic compounds

    DOEpatents

    Smith, Jr., Lawrence A.

    1989-01-01

    Aromatic compounds are alkylated in a catalytic distillation, wherein the catalyst structure also serves as a distillation component by contacting the aromatic compound with a C.sub.2 to C.sub.10 olefin in the catalyst bed under 0.25 to 50 atmospheres of pressure and at temperatures in the range of 80.degree. C. to 500.degree. C., using as the catalyst a mole sieve characterized as acidic or an acidic cation exchange resin. For example, ethyl benzene is produced by feeding ethylene below the catalyst bed while benzene is conveniently added through the reflux in molar excess to that required to react with ethylene, thereby reacting substantially all of the ethylene and recovering benzene as the principal overhead and ethyl benzene in the bottoms.

  5. Alkylation of organic aromatic compounds

    DOEpatents

    Smith, Jr., Lawrence A.; Arganbright, Robert P.; Hearn, Dennis

    1993-01-01

    Aromatic compounds are alkylated in a catalytic distillation, wherein the catalyst structure also serves as a distillation component by contacting the aromatic compound with a C.sub.2 to C.sub.10 olefin in the catalyst bed under 0.25 to 50 atmospheres of pressure and at temperatures in the range of 80.degree. C. to 500.degree. C., using as the catalyst a mole sieve characterized as acidic or an acidic cation exchange resin. For example, ethyl benzene is produced by feeding ethylene to about the mid point of the catalyst bed while benzene is conveniently added through the reflux in molar excess to that required to react with ethylene, thereby reacting substantially all of the ethylene and recovering benzene as the principal overhead and ethyl benzene in the bottoms.

  6. Alkylation of organic aromatic compounds

    DOEpatents

    Smith, L.A. Jr.; Arganbright, R.P.; Hearn, D.

    1994-06-14

    Aromatic compounds are alkylated in a catalytic distillation, wherein the catalyst structure also serves as a distillation component by contacting the aromatic compound with a C[sub 2] to C[sub 10] olefin in the catalyst bed under 0.25 to 50 atmospheres of pressure and at temperatures in the range of 80 C to 500 C, using as the catalyst a molecular sieve characterized as acidic or an acidic cation exchange resin. For example, ethyl benzene is produced by feeding ethylene below the catalyst bed while benzene is conveniently added through the reflux in molar excess to that required to react with ethylene, thereby reacting substantially all of the ethylene and recovering benzene as the principal overhead and ethyl benzene in the bottoms. 1 fig.

  7. Alkylation of organic aromatic compounds

    DOEpatents

    Smith, L.A. Jr.; Arganbright, R.P.; Hearn, D.

    1993-01-05

    Aromatic compounds are alkylated in a combination reactor/distillation column comprising a vessel suitable for operating between 70 C and 500 C and from 0.5 to 20 atmospheres pressure; an inert distillation packing in the lower one-third of said vessel; solid acidic catalytic material such as zeolites or an acidic cation exchange resin supported in the middle one-third of said vessel; and inert distillation packing in the upper one-third of said vessel. A benzene inlet is located near the upper end of the vessel; an olefin inlet is juxtaposed with said solid acidic catalytic material; a bottoms outlet is positioned near the bottom of said vessel for removing said cumene and ethyl benzene; and an overhead outlet is placed at the top of said vessel for removing any unreacted benzene and olefin.

  8. Alkylation of organic aromatic compounds

    DOEpatents

    Smith, Jr., Lawrence A.; Arganbright, Robert P.; Hearn, Dennis

    1993-01-01

    Aromatic compounds are alkylated in a combination reactor/distillation column comprising a vessel suitable for operating between 70.degree. C. and 500.degree. C. and from 0.5 to 20 atmospheres pressure; an inert distillation packing in the lower one-third of said vessel; solid acidic catalytic material such as zeolites or an acidic cation exchange resin supported in the middle one-third of said vessel; and inert distillation packing in the upper one-third of said vessel. A benzene inlet is located near the upper end of the vessel; an olefin inlet is juxtaposed with said solid acidic catalytic material; a bottoms outlet is positioned near the bottom of said vessel for removing said cumene and ethyl benzene; and an overhead outlet is placed at the top of said vessel for removing any unreacted benzene and olefin.

  9. Global simulation of aromatic volatile organic compounds in the atmosphere

    NASA Astrophysics Data System (ADS)

    Cabrera Perez, David; Taraborrelli, Domenico; Pozzer, Andrea

    2015-04-01

    Among the large number of chemical compounds in the atmosphere, the organic group plays a key role in the tropospheric chemistry. Specifically the subgroup called aromatics is of great interest. Aromatics are the predominant trace gases in urban areas due to high emissions, primarily by vehicle exhausts and fuel evaporation. They are also present in areas where biofuel is used (i.e residential wood burning). Emissions of aromatic compounds are a substantial fraction of the total emissions of the volatile organic compounds (VOC). Impact of aromatics on human health is very important, as they do not only contribute to the ozone formation in the urban environment, but they are also highly toxic themselves, especially in the case of benzene which is able to trigger a range of illness under long exposure, and of nitro-phenols which cause detrimental for humans and vegetation even at very low concentrations. The aim of this work is to assess the atmospheric impacts of aromatic compounds on the global scale. The main goals are: lifetime and budget estimation, mixing ratios distribution, net effect on ozone production and OH loss for the most emitted aromatic compounds (benzene, toluene, xylenes, ethylbenzene, styrene and trimethylbenzenes). For this purpose, we use the numerical chemistry and climate simulation ECHAM/MESSy Atmospheric Chemistry (EMAC) model to build the global atmospheric budget for the most emitted and predominant aromatic compounds in the atmosphere. A set of emissions was prepared in order to include biomass burning, vegetation and anthropogenic sources of aromatics into the model. A chemical mechanism based on the Master Chemical Mechanism (MCM) was developed to describe the chemical oxidation in the gas phase of these aromatic compounds. MCM have been reduced in terms of number of chemical equation and species in order to make it affordable in a 3D model. Additionally other features have been added, for instance the production of HONO via ortho

  10. Stable carbon isotope ratios of ambient aromatic volatile organic compounds

    NASA Astrophysics Data System (ADS)

    Kornilova, Anna; Huang, Lin; Saccon, Marina; Rudolph, Jochen

    2016-09-01

    Measurements of mixing ratios and stable carbon isotope ratios of aromatic volatile organic compounds (VOC) in the atmosphere were made in Toronto (Canada) in 2009 and 2010. Consistent with the kinetic isotope effect for reactions of aromatic VOC with the OH radical the observed stable carbon isotope ratios are on average significantly heavier than the isotope ratios of their emissions. The change of carbon isotope ratio between emission and observation is used to determine the extent of photochemical processing (photochemical age, [OH]dt) of the different VOC. It is found that [OH]dt of different VOC depends strongly on the VOC reactivity. This demonstrates that for this set of observations the assumption of a uniform [OH]dt for VOC with different reactivity is not justified and that the observed values for [OH]dt are the result of mixing of VOC from air masses with different values for [OH]dt. Based on comparison between carbon isotope ratios and VOC concentration ratios it is also found that the varying influence of sources with different VOC emission ratios has a larger impact on VOC concentration ratios than photochemical processing. It is concluded that for this data set the use of VOC concentration ratios to determine [OH]dt would result in values for [OH]dt inconsistent with carbon isotope ratios and that the concept of a uniform [OH]dt for an air mass has to be replaced by the concept of individual values of an average [OH]dt for VOC with different reactivity.

  11. Possible Mechanism of Liver Necrosis Caused by Aromatic Organic Compounds

    PubMed Central

    Brodie, Bernard B.; Reid, Watson D.; Cho, Arthur K.; Sipes, Glenn; Krishna, Gopal; Gillette, James R.

    1971-01-01

    Treatment of rats with phenobarbital, which stimulates the activity of the drug-metabolizing enzymes in the liver, potentiates hepatic necrosis elicited by bromobenzene and a number of other chemically inert halogenated aromatic hydrocarbons. Radioautographic studies indicate that [14C]bromobenzene is covalently bound at the sites of necrosis. From these results, it is inferred that the hepatotoxic effects of the halogenated aromatic hydrocarbons are mediated by chemically active metabolites formed in hepatocytes. In accord with this view, a number of aromatic halogenated hydrocarbons are converted by microsomes in vitro to active intermediates which form covalent complexes with glutathione (GSH). Images PMID:4395686

  12. Biosynthesis of polybrominated aromatic organic compounds by marine bacteria

    PubMed Central

    Agarwal, Vinayak; El Gamal, Abrahim A.; Yamanaka, Kazuya; Poth, Dennis; Kersten, Roland D.; Schorn, Michelle; Allen, Eric E.; Moore, Bradley S.

    2014-01-01

    Polybrominated diphenyl ethers (PBDEs) and polybrominated bipyrroles are natural products that bioaccumulate in the marine food chain. PBDEs have attracted widespread attention due to their persistence in the environment and potential toxicity to humans. However, the natural origins of PBDE biosynthesis are not known. Here we report marine bacteria as producers of PBDEs and establish a genetic and molecular foundation for their production that unifies paradigms for the elaboration of bromophenols and bromopyrroles abundant in marine biota. We provide biochemical evidence of marine brominase enzymes revealing decarboxylative-halogenation enzymology previously unknown among halogenating enzymes. Biosynthetic motifs discovered in our study were used to mine sequence databases to discover unrealized marine bacterial producers of organobromine compounds. PMID:24974229

  13. Lignin Peroxidase Oxidation of Aromatic Compounds in Systems Containing Organic Solvents

    PubMed Central

    Vazquez-Duhalt, Rafael; Westlake, Donald W. S.; Fedorak, Phillip M.

    1994-01-01

    Lignin peroxidase from Phanerochaete chrysosporium was used to study the oxidation of aromatic compounds, including polycyclic aromatic hydrocarbons and heterocyclic compounds, that are models of moieties of asphaltene molecules. The oxidations were done in systems containing water-miscible organic solvents, including methanol, isopropanol, N, N-dimethylformamide, acetonitrile, and tetrahydrofuran. Of the 20 aromatic compounds tested, 9 were oxidized by lignin peroxidase in the presence of hydrogen peroxide. These included anthracene, 1-, 2-, and 9-methylanthracenes, acenaphthene, fluoranthene, pyrene, carbazole, and dibenzothiophene. Of the compounds studied, lignin peroxidase was able to oxidize those with ionization potentials of <8 eV (measured by electron impact). The reaction products contain hydroxyl and keto groups. In one case, carbon-carbon bond cleavage, yielding anthraquinone from 9-methylanthracene, was detected. Kinetic constants and stability characteristics of lignin peroxidase were determined by using pyrene as the substrate in systems containing different amounts of organic solvent. Benzyl alkylation of lignin peroxidase improved its activity in a system containing water-miscible organic solvent but did not increase its resistance to inactivation at high solvent concentrations. PMID:16349176

  14. Bacterial Degradation of Aromatic Compounds

    PubMed Central

    Seo, Jong-Su; Keum, Young-Soo; Li, Qing X.

    2009-01-01

    Aromatic compounds are among the most prevalent and persistent pollutants in the environment. Petroleum-contaminated soil and sediment commonly contain a mixture of polycyclic aromatic hydrocarbons (PAHs) and heterocyclic aromatics. Aromatics derived from industrial activities often have functional groups such as alkyls, halogens and nitro groups. Biodegradation is a major mechanism of removal of organic pollutants from a contaminated site. This review focuses on bacterial degradation pathways of selected aromatic compounds. Catabolic pathways of naphthalene, fluorene, phenanthrene, fluoranthene, pyrene, and benzo[a]pyrene are described in detail. Bacterial catabolism of the heterocycles dibenzofuran, carbazole, dibenzothiophene, and dibenzodioxin is discussed. Bacterial catabolism of alkylated PAHs is summarized, followed by a brief discussion of proteomics and metabolomics as powerful tools for elucidation of biodegradation mechanisms. PMID:19440284

  15. The rate of photocatalytic oxidation of aromatic volatile organic compounds in the gas-phase

    NASA Astrophysics Data System (ADS)

    Boulamanti, Aikaterini K.; Korologos, Christos A.; Philippopoulos, Constantine J.

    In the present study, the gas-solid heterogeneous photocatalytic oxidation (PCO) of six aromatic species of volatile organic compounds (VOCs), benzene, toluene, ethylbenzene, m-, o- and p-xylene over illuminated titania was carried out at ambient temperature in a continuous stirring-tank reactor. Initial VOC concentrations were in the low parts per million (ppm) range. Maximum conversions were over 90% for all compounds except from benzene, ethylbenzene and o-xylene, while the residence time varied from 50 to 210 s. Intermediates were detected only in the case of the xylenes, but catalyst deactivation occurred for all six compounds. The PCO kinetics were well fit by a Langmuir-Hinshelwood (L-H) model for monomolecular surface reaction and it was proved that the reaction rate is related to both constants. The rate constants ranged from 0.147 ppm s -1 g cat-1 for benzene to 1.067 ppm s -1 g cat-1 for m-xylene, while the adsorption constants from 0.424 ppm -1 for ethylbenzene to 0.69 ppm -1 for toluene. The molecular structure of the compounds was found to play an important role in the reaction. Finally the efficiency of the procedure in the case of a mixture of these aromatic substances was tested.

  16. Analysis of industrial contaminants in indoor air: part 1. Volatile organic compounds, carbonyl compounds, polycyclic aromatic hydrocarbons and polychlorinated biphenyls.

    PubMed

    Barro, Ruth; Regueiro, Jorge; Llompart, María; Garcia-Jares, Carmen

    2009-01-16

    This article reviews recent literature on the analysis of industrial contaminants in indoor air in the framework of the REACH project, which is mainly intended to improve protection of human health and the environment from the risks of more than 34 millions of chemical substances. Industrial pollutants that can be found in indoor air may be of very different types and origin, belonging to the volatile organic compounds (VOCs) and semivolatile organic compounds (SVOCs) categories. Several compounds have been classified into the priority organic pollutants (POPs) class such as polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins and furans (PCDD/PCDFs) and related polychlorinated compounds, and polycyclic aromatic hydrocarbons (PAHs). Many of these compounds are partially associated to the air gas phase, but also to the suspended particulate matter. Furthermore, settled dust can act as a concentrator for the less volatile pollutants and has become a matrix of great concern for indoors contamination. Main literature considered in this review are papers from the last 10 years reporting analytical developments and applications regarding VOCs, aldehydes and other carbonyls, PCBs, PCDDs, PCDFs, and PAHs in the indoor environment. Sample collection and pretreatment, analyte extraction, clean-up procedures, determination techniques, performance results, as well as compound concentrations in indoor samples, are summarized and discussed. Emergent contaminants and pesticides related to the industrial development that can be found in indoor air are reviewed in a second part in this volume.

  17. Effects of gasoline aromatic content on emissions of volatile organic compounds and aldehydes from a four-stroke motorcycle.

    PubMed

    Yao, Yung-Chen; Tsai, Jiun-Horng

    2013-01-01

    A new four-stroke carburettor motorcycle engine without any engine adjustments was used to study the impact of fuel aromatic content on the exhaust emissions of organic air pollutants (volatile organic compounds and carbonyls). Three levels of aromatic content, i.e. 15, 25, and 50% (vol.) aromatics mixed with gasoline were tested. The emissions of aromatic fuel were compared with those of commercial unleaded gasoline. The results indicated that the A 15 (15 vol% aromatics in gasoline) fuel exhibited the greatest total organic emission improvement among these three aromatic fuels as compared with commercial gasoline, reaching 59%. The highest emission factors of alkanes, alkenes, and carbonyl groups appeared in the reference fuel (RF) among all of the test fuels. A 15 showed the highest emission reduction in alkanes (73%), aromatics (36%), and carbonyls (28%), as compared to those of the RF. The highest emission reduction ofalkenes was observed when using A25 as fuel. A reduction in fuel aromatic content from 50 to 25 and 15 vol% in gasoline decreased benzene and toluene emissions, but increased the aldehyde emissions. In general, the results showed that the highest emission reductions for the most of measured organic pollutants appeared when using A 15 as the fuel.

  18. Polymer-assisted deposition of co-doped zinc oxide thin films for the detection of aromatic organic compounds.

    PubMed

    Li, Wei; Kim, Dojin

    2011-12-01

    Co-doped Zinc oxide thin films are deposited onto SiO2/Si substrate by polymer-assisted deposition method. The surface morphology, structures and chemical states of the thin films are examined by scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The gas-sensing properties of the thin films upon exposure to aromatic organic compound vapors are also investigated. Co-doping is shown to be very effective in enhancing the response of ZnO thin film to aromatic organic compound.

  19. Sorption of aromatic ionizable organic compounds to montmorillonites modified by hexadecyltrimethyl ammonium and polydiallyldimethyl ammonium.

    PubMed

    Xu, Huaizhou; Wan, Yuqiu; Li, Hui; Zheng, Shourong; Zhu, Dongqiang

    2011-01-01

    Environmental residues of aromatic ionizable organic compounds (AIOCs) have received considerable attention due to their potential human health and ecological risks. The main objective of this study was to investigate the key factors and mechanisms controlling sorption of a series of anionic and zwitterionic AIOCs (two aromatic sulfonates, 4-methyl-2,6-dinitrophenol, tetracycline, sulfamethoxazole, and tannic acid) to montmorillonites modified with hexadecyltrimethyl ammonium (HDTMA) and polydiallyldimethyl ammonium (PDADMA). Compared with naphthalene (a nonpolar and nonionic solute), all AIOCs showed stronger sorption (the sorbent-to-solution distribution coefficient was in the order of 10-10 L kg) to the two organoclays in spite of the much lower hydrophobicity, indicating the predominance of electrostatic interaction in sorption. The proposed electrostatic mechanism of the tested AIOCs was supported by the pH dependency of sorption to the two organoclays. The two organoclays manifested weaker sorption affinity but faster sorption kinetics for bulky AIOCs than commercial activated carbon, resulting from the high accessibility of sorption sites in the open, ordered clay interlayer. The findings of this study highlight the potential of using HDTMA- and PDADMA-exchanged montmorillonites as effective sorbents for AIOCs in water and wastewater treatments.

  20. Volatile organic compounds, polycyclic aromatic hydrocarbons and elements in the air of ten urban homes.

    PubMed

    Van Winkle, M R; Scheff, P A

    2001-03-01

    Ten homes were monitored at regular intervals from June 1994 through April 1995 as part of a Public Health Assessment in Southeast Chicago for exposure to volatile organic compounds (VOCs), polycyclic aromatic hydrocarbons (PAHs), and elements. Simultaneous 24-h indoor and outdoor samples were collected. VOCs were and analyzed using USEPA Method TO-14 with Selected Ion Monitoring Mass Spectrometry (GC/MS). PAHs were analyzed using USEPA Method TO-13 with GC/MS. Elements were collected on quartz fiber filters and analyzed by Inductively Coupled Argon Plasma (ICP) spectroscopy or Graphite Furnace Atomic Absorption (GFAA). Continuous measurements of CO2 and temperature were recorded for each indoor sample. Twenty-four h total CO2 emissions were determined from occupancy and estimated gas stove usage and were moderately correlated (R2 = 0.19) with 24 h average indoor CO2 concentrations. Modeled 24-h air exchange rates ranged from 0.04 to 3.76 air changes h-1 (ACH), with mean of 0.52 ACH. Median particle penetration was 0.89. Emission rates were calculated for each pollutant sampled. Using a detailed housing survey and field sampling questionnaires, it was possible to evaluate associations between housing characteristics and source activities, and pollutant source rates. The data indicate that several predictor variables, including mothball storage, air freshner use, and cooking activities, are reasonable predictors for emission rates for specific pollutants in the homes studied.

  1. High-field FT-ICR-MS and aromaticity equivalent approach for structural identification of water soluble organic compounds (WSOC)

    NASA Astrophysics Data System (ADS)

    Harir, Mourad; Yassine, Mahmoud M.; Dabek-Zlotorzynska, Ewa; Hertkorn, Norbert; Schmitt-Kopplin, Philippe

    2015-04-01

    Organic aerosol (OA) makes up a large and often dominant fraction, (20 to 90%) of the submicron atmospheric particulate mass, and its effects are becoming increasingly important in determining climatic and health effects of atmospheric aerosols. Despite the abundance of OA, our understanding of the sources, formation processes and atmospheric properties of OA is limited. Atmospheric OA has both primary (directly emitted) and secondary (formed in the atmosphere from precursor gases) sources, which can be natural (e.g. vegetation) and/or anthropogenic (e.g. fossil-based vehicle exhaust or biomass burning). A significant fraction of OA contains as much as 20-70% of water soluble organic compounds (WSOC). The WSOC fraction is a very complex mixture of low volatility, polyfunctional aliphatic and aromatic compounds containing carboxyl, alcohol, carbonyl, sulfo, nitro, and other functionalities. This high degree of chemical complexity of atmospheric organics has inspired a number of sophisticated approaches that are capable of identifying and detecting a variety of different analytes in OA. Accordingly, one of the most challenging areas of atmospheric particulate matter (PM) analysis is to comprehend the molecular complexity of the OA, especially WSOC fraction, a significant component of atmospheric fine PM (PM2.5). The sources of WSOC are not well understood, especially the relative contributions of primary vs. secondary organic aerosol. Therefore, the molecular characterization of WSOC is important because it allows gaining insight into aerosol sources and underlying mechanisms of secondary organic aerosols (SOA) formation and transformation. In this abstract, molecular characterization of WSOC was achieved using high-field mass spectrometry FT-ICR-MS and aromaticity equivalent approach. Aromaticity equivalent (Xc), defined recently as a new parameter calculated from the assigned molecular formulas (complementary to the aromaticity index [1]), is introduced to improve

  2. Heterogeneous photocatalytic reactions of sulfur aromatic compounds.

    PubMed

    Samokhvalov, Alexander

    2011-11-18

    Sulfur aromatic compounds, such as mono-, di-, tri-, and tetraalkyl-substituted thiophene, benzothiophenes, dibenzothiophenes, are the molecular components of many fossils (petroleum, oil shale, tar sands, bitumen). Structural units of natural, cross-linked heteroaromatic polymers present in brown coals, turf, and soil are similar to those of sulfur aromatic compounds. Many sulfur aromatic compounds are found in the streams of petroleum refining and upgrading (naphthas, gas oils) and in the consumer products (gasoline, diesel, jet fuels, heating fuels). Besides fossils, the structural fragments of sulfur aromatic compounds are present in molecules of certain organic semiconductors, pesticides, small molecule drugs, and in certain biomolecules present in human body (pheomelanin pigments). Photocatalysis is the frontier area of physical chemistry that studies chemical reactions initiated by absorption of photons by photocatalysts, that is, upon electronic rather than thermal activation, under "green" ambient conditions. This review provides systematization and critical review of the fundamental chemical and physicochemical information on heterogeneous photocatalysis of sulfur aromatic compounds accumulated in the last 20-30 years. Specifically, the following topics are covered: physicochemical properties of sulfur aromatic compounds, major classes of heterogeneous photocatalysts, mechanisms and reactive intermediates of photocatalytic reactions of sulfur aromatic compounds, and the selectivity of these reactions. Quantum chemical calculations of properties and structures of sulfur aromatic compounds, their reactive intermediates, and the structure of adsorption complexes formed on the surface of the photocatalysts are also discussed.

  3. Biodegradation of Aromatic Compounds by Escherichia coli

    PubMed Central

    Díaz, Eduardo; Ferrández, Abel; Prieto, María A.; García, José L.

    2001-01-01

    Although Escherichia coli has long been recognized as the best-understood living organism, little was known about its abilities to use aromatic compounds as sole carbon and energy sources. This review gives an extensive overview of the current knowledge of the catabolism of aromatic compounds by E. coli. After giving a general overview of the aromatic compounds that E. coli strains encounter and mineralize in the different habitats that they colonize, we provide an up-to-date status report on the genes and proteins involved in the catabolism of such compounds, namely, several aromatic acids (phenylacetic acid, 3- and 4-hydroxyphenylacetic acid, phenylpropionic acid, 3-hydroxyphenylpropionic acid, and 3-hydroxycinnamic acid) and amines (phenylethylamine, tyramine, and dopamine). Other enzymatic activities acting on aromatic compounds in E. coli are also reviewed and evaluated. The review also reflects the present impact of genomic research and how the analysis of the whole E. coli genome reveals novel aromatic catabolic functions. Moreover, evolutionary considerations derived from sequence comparisons between the aromatic catabolic clusters of E. coli and homologous clusters from an increasing number of bacteria are also discussed. The recent progress in the understanding of the fundamentals that govern the degradation of aromatic compounds in E. coli makes this bacterium a very useful model system to decipher biochemical, genetic, evolutionary, and ecological aspects of the catabolism of such compounds. In the last part of the review, we discuss strategies and concepts to metabolically engineer E. coli to suit specific needs for biodegradation and biotransformation of aromatics and we provide several examples based on selected studies. Finally, conclusions derived from this review may serve as a lead for future research and applications. PMID:11729263

  4. Biodegradation of aromatic compounds by Escherichia coli.

    PubMed

    Díaz, E; Ferrández, A; Prieto, M A; García, J L

    2001-12-01

    Although Escherichia coli has long been recognized as the best-understood living organism, little was known about its abilities to use aromatic compounds as sole carbon and energy sources. This review gives an extensive overview of the current knowledge of the catabolism of aromatic compounds by E. coli. After giving a general overview of the aromatic compounds that E. coli strains encounter and mineralize in the different habitats that they colonize, we provide an up-to-date status report on the genes and proteins involved in the catabolism of such compounds, namely, several aromatic acids (phenylacetic acid, 3- and 4-hydroxyphenylacetic acid, phenylpropionic acid, 3-hydroxyphenylpropionic acid, and 3-hydroxycinnamic acid) and amines (phenylethylamine, tyramine, and dopamine). Other enzymatic activities acting on aromatic compounds in E. coli are also reviewed and evaluated. The review also reflects the present impact of genomic research and how the analysis of the whole E. coli genome reveals novel aromatic catabolic functions. Moreover, evolutionary considerations derived from sequence comparisons between the aromatic catabolic clusters of E. coli and homologous clusters from an increasing number of bacteria are also discussed. The recent progress in the understanding of the fundamentals that govern the degradation of aromatic compounds in E. coli makes this bacterium a very useful model system to decipher biochemical, genetic, evolutionary, and ecological aspects of the catabolism of such compounds. In the last part of the review, we discuss strategies and concepts to metabolically engineer E. coli to suit specific needs for biodegradation and biotransformation of aromatics and we provide several examples based on selected studies. Finally, conclusions derived from this review may serve as a lead for future research and applications.

  5. Electron delocalization and aromaticity in low-lying excited states of archetypal organic compounds.

    PubMed

    Feixas, Ferran; Vandenbussche, Jelle; Bultinck, Patrick; Matito, Eduard; Solà, Miquel

    2011-12-14

    Aromaticity is a property usually linked to the ground state of stable molecules. Although it is well-known that certain excited states are unquestionably aromatic, the aromaticity of excited states remains rather unexplored. To move one step forward in the comprehension of aromaticity in excited states, in this work we analyze the electron delocalization and aromaticity of a series of low-lying excited states of cyclobutadiene, benzene, and cyclooctatetraene with different multiplicities at the CASSCF level by means of electron delocalization measures. While our results are in agreement with Baird's rule for the aromaticity of the lowest-lying triplet excited state in annulenes having 4nπ-electrons, they do not support Soncini and Fowler's generalization of Baird's rule pointing out that the lowest-lying quintet state of benzene and septet state of cyclooctatetraene are not aromatic.

  6. Detection of chlorinated aromatic compounds

    DOEpatents

    Ekechukwu, Amy A.

    1996-01-01

    A method for making a composition for measuring the concentration of chloated aromatic compounds in aqueous fluids, and an optical probe for use with the method. The composition comprises a hydrophobic polymer matrix, preferably polyamide, with a fluorescent indicator uniformly dispersed therein. The indicator fluoresces in the presence of the chlorinated aromatic compounds with an intensity dependent on the concentration of these compounds in the fluid of interest, such as 8-amino-2-naphthalene sulfonate. The probe includes a hollow cylindrical housing that contains the composition in its distal end. The probe admits an aqueous fluid to the probe interior for exposure to the composition. An optical fiber transmits excitation light from a remote source to the composition while the indicator reacts with chlorinated aromatic compounds present in the fluid. The resulting fluorescence light signal is reflected to a second optical fiber that transmits the light to a spectrophotometer for analysis.

  7. Detection of chlorinated aromatic compounds

    DOEpatents

    Ekechukwu, A.A.

    1996-02-06

    A method for making a composition for measuring the concentration of chlorinated aromatic compounds in aqueous fluids, and an optical probe for use with the method are disclosed. The composition comprises a hydrophobic polymer matrix, preferably polyamide, with a fluorescent indicator uniformly dispersed therein. The indicator fluoresces in the presence of the chlorinated aromatic compounds with an intensity dependent on the concentration of these compounds in the fluid of interest, such as 8-amino-2-naphthalene sulfonate. The probe includes a hollow cylindrical housing that contains the composition in its distal end. The probe admits an aqueous fluid to the probe interior for exposure to the composition. An optical fiber transmits excitation light from a remote source to the composition while the indicator reacts with chlorinated aromatic compounds present in the fluid. The resulting fluorescence light signal is reflected to a second optical fiber that transmits the light to a spectrophotometer for analysis. 5 figs.

  8. Reaction of bromine and chlorine with phenolic compounds and natural organic matter extracts--Electrophilic aromatic substitution and oxidation.

    PubMed

    Criquet, Justine; Rodriguez, Eva M; Allard, Sebastien; Wellauer, Sven; Salhi, Elisabeth; Joll, Cynthia A; von Gunten, Urs

    2015-11-15

    Phenolic compounds are known structural moieties of natural organic matter (NOM), and their reactivity is a key parameter for understanding the reactivity of NOM and the disinfection by-product formation during oxidative water treatment. In this study, species-specific and/or apparent second order rate constants and mechanisms for the reactions of bromine and chlorine have been determined for various phenolic compounds (phenol, resorcinol, catechol, hydroquinone, phloroglucinol, bisphenol A, p-hydroxybenzoic acid, gallic acid, hesperetin and tannic acid) and flavone. The reactivity of bromine with phenolic compounds is very high, with apparent second order rate constants at pH 7 in the range of 10(4) to 10(7) M(-1) s(-1). The highest value was recorded for the reaction between HOBr and the fully deprotonated resorcinol (k = 2.1 × 10(9) M(-1) s(-1)). The reactivity of phenolic compounds is enhanced by the activating character of the phenolic substituents, e.g. further hydroxyl groups. With the data set from this study, the ratio between the species-specific rate constants for the reactions of chlorine versus bromine with phenolic compounds was confirmed to be about 3000. Phenolic compounds react with bromine or chlorine either by oxidation (electron transfer, ET) or electrophilic aromatic substitution (EAS) processes. The dominant process mainly depends on the relative position of the hydroxyl substituents and the possibility of quinone formation. While phenol, p-hydroxybenzoic acid and bisphenol A undergo EAS, hydroquinone, catechol, gallic acid and tannic acid, with hydroxyl substituents in ortho or para positions, react with bromine by ET leading to quantitative formation of the corresponding quinones. Some compounds (e.g. phloroglucinol) show both partial oxidation and partial electrophilic aromatic substitution and the ratio observed for the pathways depends on the pH. For the reaction of six NOM extracts with bromine, electrophilic aromatic substitution

  9. Solvothermal synthesis of CdIn2S4 photocatalyst for selective photosynthesis of organic aromatic compounds under visible light.

    PubMed

    Ling, Cancan; Ye, Xiangju; Zhang, Jinghu; Zhang, Jinfeng; Zhang, Sujuan; Meng, Sugang; Fu, Xianliang; Chen, Shifu

    2017-12-01

    Ternary chalcogenide semiconductor, cadmium indium sulfide (CdIn2S4), was prepared by a simple solvothermal method using ethylene glycol as a solvent, as well as indium chloride tetrahydrate (InCl3(.)4H2O), cadmium nitrate tetrahydrate [Cd(NO3)2(.)4H2O], and thiacetamide (TAA) as precursors. The resulted sample was subject to a series of characterizations. It is the first time to use CdIn2S4 sample as a visible light-driven photocatalyst for simultaneous selective redox transformation of organic aromatic compounds. The results indicate that the as-synthesized CdIn2S4 photocatalyst not only has excellent photocatalytic performance compared with pure In2S3 and CdS for the selective oxidation of aromatic alcohols in an oxygen environment, but also shows high photocatalytic redox activities under nitrogen atmosphere. A possible mechanism for the photocatalytic redox reaction in the coupled system was proposed. It is hoped that our current work could extend the applications of CdIn2S4 photocatalyst and provide new insights for selective transformations of organic compounds.

  10. Vehicle occupants' exposure to aromatic volatile organic compounds while commuting on an urban-suburban route in Korea.

    PubMed

    Jo, W K; Choi, S J

    1996-08-01

    This study identified in-auto and in-bus exposures to six selected aromatic volatile organic compounds (VOCs) for commutes on an urban-suburban route in Korea. A bus-service route was selected to include three segments of Taegu and one suburban segment (Hayang) to satisfy the criteria specified for this study. This study indicates that motor vehicle exhaust and evaporative emissions are major sources of both auto and bus occupants' exposures to aromatic VOCs in both Taegu and Hayang. A nonparametric statistical test (Wilcoxon test) showed that in-auto benzene levels were significantly different from in-bus benzene levels for both urban-segment and suburban-segment commutes. The test also showed that the benzene-level difference between urban-segment and suburban-segment commutes was significant for both autos and buses. An F-test showed the same statistical results for the comparison of the summed in-vehicle concentration of the six target VOCs (benzene, toluene, ethylbenzene, and o,m,p-xylenes) as those for the comparison of the in-vehicle benzene concentration. On the other hand, the in-vehicle benzene level only and the sum were not significantly different among the three urban-segment commutes and between the morning and evening commutes. The in-auto VOC concentrations were intermediate between the results for the Los Angeles and Boston. The in-bus VOC concentrations were about one-tenth of the Taipei, Taiwan results.

  11. Hydrogen and carbon isotopic ratios of polycyclic aromatic compounds in two CM2 carbonaceous chondrites and implications for prebiotic organic synthesis

    NASA Astrophysics Data System (ADS)

    Huang, Yongsong; Aponte, José C.; Zhao, Jiaju; Tarozo, Rafael; Hallmann, Christian

    2015-09-01

    Study of meteoritic organic compounds offers a unique opportunity to understand the origins of the organic matter in the early Solar System. Meteoritic polycyclic aromatic hydrocarbons (PAHs) and heteropolycyclic aromatic compounds (HACs) have been studied for over fifty years, however; their hydrogen stable isotopic ratios (δD) have never been reported. Compound-specific δD measurements of PAHs and HACs are important, in part because the carbon isotopic ratios (δ13C) of various meteoritic PAHs cannot be readily distinguished from their terrestrial counterparts and it is difficult to rule out terrestrial contamination based on carbon isotopic ratios alone. In this study, we have extracted and identified more than sixty PAHs and HACs present in two CM2 carbonaceous chondrites Murchison and LON 94101. Their carbon and hydrogen stable isotopic ratios (δ13C and δD) were measured and used to discuss about their synthetic environments and formation mechanisms. The concentration of aromatic compounds is ∼30% higher in Murchison than in the Antarctic meteorite LON 94101, but both samples contained similar suites of PAHs and HACs. All PAHs and HACs found exhibited positive δD values (up to 1100‰) consistent with an extraterrestrial origin, indicating the relatively low δ13C values are indeed an inherent feature of the meteoritic aromatic compounds. The hydrogen isotopic data suggest aromatic compounds in carbonaceous chondrites were mainly formed in the cold interstellar environments. Molecular level variations in hydrogen and carbon isotopic values offer new insights to the formation pathways for the aromatic compounds in carbonaceous chondrites.

  12. Characterization of trace organic compounds associated with aged and diluted sidestream tobacco smoke in a controlled atmosphere—volatile organic compounds and polycyclic aromatic hydrocarbons

    NASA Astrophysics Data System (ADS)

    Baek, Sung-Ok; Jenkins, Roger A.

    In this study, a wide range of volatile organic constituents of aged and diluted sidestream tobacco smoke (ADSS) were determined in a controlled atmosphere, where ADSS is the sole source of target compounds. The ADSS was generated in a 30 m 3 environmental test chamber using a variety of cigarettes, including the Kentucky 1R4F reference cigarette and eight commercial brands, and a total of 24 experimental runs were conducted. Target analytes were divided into three groups, i.e. vapor and particulate phase markers for environmental tobacco smoke (ETS), volatile organic compounds (VOC) including carbonyls, and polycyclic aromatic hydrocarbons (PAH). The VOC samples were collected on triple sorbent traps, and then analyzed by thermal desorption coupled with gas chromatography/mass spectrometry (GC/MS), while the carbonyl compounds were sampled on DNPH cartridges, being analyzed by HPLC. ETS particles in the chamber were collected by high volume sampling, and then used for the determination of PAHs by GC/MS. Among more than 30 target VOCs, acetaldehyde appeared to be the most abundant compound, followed by 2-methyl-1,3-butadiene, and formaldehyde. The results from the chamber study were further used to generate characterized ratios of selected VOCs to 3-ethenyl pyridine (3-EP), a vapor phase ETS marker. The ratios appeared to be in generally good agreement with published values in the literature. This suggests that the characteristic ratios may be useful for quantifying the impact of ETS on the VOC concentrations in 'real world' indoor environments, which are affected by a complex mixture of components from multiple sources. The yields of ETS markers from this study are all slightly lower than those estimated by other studies, while VOC yields are in reasonable agreement in many cases with values in the literature. Among 16 target PAHs, chrysene appeared to be most abundant, followed by benzo(a)anthracene (BaA) and benzo(a)pyrene (BaP). The average contents of BaP and

  13. Overview of Polycyclic Aromatic Compounds (PAC)

    PubMed Central

    Achten, Christine; Andersson, Jan T.

    2015-01-01

    The chemical group of polycyclic aromatic compounds (PAC), including the better-known subgroup of polycyclic aromatic hydrocarbons (PAH) and the heterocyclic aromatic compounds (NSO-PAC, heterocycles), comprise several thousand individual compounds. It is hard to find a comprehensive overview in the literature of these PACs that includes a substantial amount of relevant properties. Here an attempt is made to summarize the most studied but also some less well-known PACs. In addition to basic data such as recommended names, abbreviations, CAS numbers, molecular formulas, chemical structures, and exact mono-isotopic molecular weights, physico-chemical properties taken from the literature like boiling points, vapor pressures, water solubilities, Henry's Law constants, n-octanol-water partition coefficients (log KOW), and pKa are summarized. Selected toxicological data are listed indicating carcinogenic and mutagenic activity or effects on different organisms. PAC nomenclature is a complex topic, so suggestions for practical use are made. Regarding available data, estimated (instead of measured) values should be used with caution because considerable deviations from experimentally determined values can occur. For an enhanced understanding of the behavior of single PACs in comparison with each other, some of the properties mentioned above are plotted vs. the number of rings or the degree of alkylation. Also, some physico-chemical data are correlated with different functional groups as substituents of the PAHs. This article reveals that rather little is known about the less common PACs, e.g., higher molecular weight compounds, alkylated or otherwise substituted aromatics, for instance, keto-, oxo-, amino-, nitro-, cyano-PAHs, or some heterocyclic aromatic compounds, including their derivatives. It mirrors the limited state of knowledge about the variety of PACs that do not belong to the 16 EPA PAHs. PMID:26823644

  14. Overview of Polycyclic Aromatic Compounds (PAC).

    PubMed

    Achten, Christine; Andersson, Jan T

    2015-03-15

    The chemical group of polycyclic aromatic compounds (PAC), including the better-known subgroup of polycyclic aromatic hydrocarbons (PAH) and the heterocyclic aromatic compounds (NSO-PAC, heterocycles), comprise several thousand individual compounds. It is hard to find a comprehensive overview in the literature of these PACs that includes a substantial amount of relevant properties. Here an attempt is made to summarize the most studied but also some less well-known PACs. In addition to basic data such as recommended names, abbreviations, CAS numbers, molecular formulas, chemical structures, and exact mono-isotopic molecular weights, physico-chemical properties taken from the literature like boiling points, vapor pressures, water solubilities, Henry's Law constants, n-octanol-water partition coefficients (log KOW), and pKa are summarized. Selected toxicological data are listed indicating carcinogenic and mutagenic activity or effects on different organisms. PAC nomenclature is a complex topic, so suggestions for practical use are made. Regarding available data, estimated (instead of measured) values should be used with caution because considerable deviations from experimentally determined values can occur. For an enhanced understanding of the behavior of single PACs in comparison with each other, some of the properties mentioned above are plotted vs. the number of rings or the degree of alkylation. Also, some physico-chemical data are correlated with different functional groups as substituents of the PAHs. This article reveals that rather little is known about the less common PACs, e.g., higher molecular weight compounds, alkylated or otherwise substituted aromatics, for instance, keto-, oxo-, amino-, nitro-, cyano-PAHs, or some heterocyclic aromatic compounds, including their derivatives. It mirrors the limited state of knowledge about the variety of PACs that do not belong to the 16 EPA PAHs.

  15. Chapter 3. Determination of semivolatile organic compounds and polycyclic aromatic hydrocarbons in solids by gas chromatography/mass spectrometry

    USGS Publications Warehouse

    Zaugg, Steven D.; Burkhardt, Mark R.; Burbank, Teresa L.; Olson, Mary C.; Iverson, Jana L.; Schroeder, Michael P.

    2006-01-01

    A method for the determination of 38 polycyclic aromatic hydrocarbons (PAHs) and semivolatile organic compounds in solid samples is described. Samples are extracted using a pressurized solvent extraction system. The compounds of interest are extracted from the solid sample twice at 13,800 kilopascals; first at 120 degrees Celsius using a water/isopropyl alcohol mixture (50:50, volume-to-volume ratio), and then the sample is extracted at 200 degrees Celsius using a water/isopropyl alcohol mixture (80:20, volume-to-volume ratio). The compounds are isolated using disposable solid-phase extraction (SPE) cartridges containing divinylbenzene-vinylpyrrolidone copolymer resin. The cartridges are dried with nitrogen gas, and then sorbed compounds are eluted from the SPE material using a dichloromethane/diethyl ether mixture (80:20, volume-to-volume ratio) and passed through a sodium sulfate/Florisil SPE cartridge to remove residual water and to further clean up the extract. The concentrated extract is solvent exchanged into ethyl acetate and the solvent volume reduced to 0.5 milliliter. Internal standard compounds are added prior to analysis by capillary-column gas chromatography/mass spectrometry. Comparisons of PAH data for 28 sediment samples extracted by Soxhlet and the accelerated solvent extraction (ASE) method described in this report produced similar results. Extraction of PAH compounds from standard reference material using this method also compared favorably with Soxhlet extraction. The recoveries of PAHs less than molecular weight 202 (pyrene or fluoranthene) are higher by up to 20 percent using this ASE method, whereas the recoveries of PAHs greater than or equal to molecular weight 202 are equivalent. This ASE method of sample extraction of solids has advantages over conventional Soxhlet extraction by increasing automation of the extraction process, reducing extraction time, and using less solvent. Extract cleanup also is greatly simplified because SPE replaces

  16. Development of the New Approaches in Designing of Fluoroorganic Derivatives Sulfur (Unsaturated, Heterocyclic, Aromatic Molecular Systems and Polyfunctional Organic Compounds)

    DTIC Science & Technology

    2005-11-15

    electrophilic fluorinating agents R2N-F, [R3N-F]+ A-; Stage 3. The investigation of pentafluorosulfanylation of different unsaturated, aromatic and...study of reaction fluorination of ethers with pentafluorothio groups (SF5), nitro (NO2) groups and related compounds having electron-withdrawing...fragment 27 9. Exploring the fluorination of thionocarbonates and acetals 30 10. Experimental section. 31 11. Conclusion. 63 12

  17. Development of urine standard reference materials for metabolites of organic chemicals including polycyclic aromatic hydrocarbons, phthalates, phenols, parabens, and volatile organic compounds

    PubMed Central

    Schantz, Michele M.; Benner, Bruce A.; Heckert, N. Alan; Sander, Lane C.; Sharpless, Katherine E.; Vander Pol, Stacy S.; Vasquez, Y.; Villegas, M.; Wise, Stephen A.; Alwis, K. Udeni; Blount, Benjamin C.; Calafat, Antonia M.; Li, Zheng; Silva, Manori J.; Ye, Xiaoyun; Gaudreau, Éric; Patterson, Donald G.; Sjödin, Andreas

    2016-01-01

    Two new Standard Reference Materials (SRMs), SRM 3672 Organic Contaminants in Smokers’ Urine (Frozen) and SRM 3673 Organic Contaminants in Non-Smokers’ Urine (Frozen), have been developed in support of studies for assessment of human exposure to select organic environmental contaminants. Collaborations among three organizations resulted in certified values for 11 hydroxylated polycyclic aromatic hydrocarbons (OH-PAHs) and reference values for 11 phthalate metabolites, 8 environmental phenols and parabens, and 24 volatile organic compound (VOC) metabolites. Reference values are also available for creatinine and the free forms of caffeine, theobromine, ibuprofen, nicotine, cotinine, and 3-hydroxycotinine. These are the first urine Certified Reference Materials characterized for metabolites of organic environmental contaminants. Noteworthy, the mass fractions of the environmental organic contaminants in the two SRMs are within the ranges reported in population survey studies such as the National Health and Nutrition Examination Survey (NHANES) and the Canadian Health Measures Survey (CHMS). These SRMs will be useful as quality control samples for ensuring compatibility of results among population survey studies and will fill a void to assess the accuracy of analytical methods used in studies monitoring human exposure to these organic environmental contaminants. PMID:25651899

  18. Anaerobic Catabolism of Aromatic Compounds: a Genetic and Genomic View

    PubMed Central

    Carmona, Manuel; Zamarro, María Teresa; Blázquez, Blas; Durante-Rodríguez, Gonzalo; Juárez, Javier F.; Valderrama, J. Andrés; Barragán, María J. L.; García, José Luis; Díaz, Eduardo

    2009-01-01

    Summary: Aromatic compounds belong to one of the most widely distributed classes of organic compounds in nature, and a significant number of xenobiotics belong to this family of compounds. Since many habitats containing large amounts of aromatic compounds are often anoxic, the anaerobic catabolism of aromatic compounds by microorganisms becomes crucial in biogeochemical cycles and in the sustainable development of the biosphere. The mineralization of aromatic compounds by facultative or obligate anaerobic bacteria can be coupled to anaerobic respiration with a variety of electron acceptors as well as to fermentation and anoxygenic photosynthesis. Since the redox potential of the electron-accepting system dictates the degradative strategy, there is wide biochemical diversity among anaerobic aromatic degraders. However, the genetic determinants of all these processes and the mechanisms involved in their regulation are much less studied. This review focuses on the recent findings that standard molecular biology approaches together with new high-throughput technologies (e.g., genome sequencing, transcriptomics, proteomics, and metagenomics) have provided regarding the genetics, regulation, ecophysiology, and evolution of anaerobic aromatic degradation pathways. These studies revealed that the anaerobic catabolism of aromatic compounds is more diverse and widespread than previously thought, and the complex metabolic and stress programs associated with the use of aromatic compounds under anaerobic conditions are starting to be unraveled. Anaerobic biotransformation processes based on unprecedented enzymes and pathways with novel metabolic capabilities, as well as the design of novel regulatory circuits and catabolic networks of great biotechnological potential in synthetic biology, are now feasible to approach. PMID:19258534

  19. Detection of Non-aromatic Organic Compounds in Meteorites using Imaging Laser Desorption/Ionization Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Scott, J. R.; Hinman, N. W.; Richardson, C. D.; Mahon, R. C.; McJunkin, T. R.

    2009-12-01

    Our most extensive understanding of extraterrestrial organic matter is based on what has been learned from meteorites that have been delivered naturally to Earth. Meteorites have been analyzed by a variety of techniques ranging from extensive sample preparation with extraction and subsequent chromatography to direct laser desorption mass spectrometry (LDMS). While extraction studies have reported a variety of organics (e.g., aliphatic and aromatic hydrocarbons, ketones, aldehydes, and amino acids), LDMS studies have only reported polycyclic aromatic hydrocarbons (PAHs). This is rather surprising considering that Yan et al. (Talanta 2007, 72, 634-641) reported that even a small amount of PAH enables the detection of organics that are not otherwise ionized during the desorption event from minerals. Therefore, we have begun re-investigating meteorites because, regardless of the source of the organic compounds, the presences of PAHs should allow other organic molecules to be observed using imaging laser desorption/ionization Fourier transform ion cyclotron resonance mass spectrometry (LD-FTICR-MS). Indeed, we have mapped meteorites (e.g., EETA 79001) and found many mass-to-charge peaks that are non-aromatic as determined by analysis of their mass defects. Mapping also revealed that the distribution of organics is heterogeneous, which necessitates the collection of a mass spectrum from a single laser shot so that minor peaks of interest are not lost in signal averaging. These studies have implications for analyzing future returned samples from Mars or elsewhere with minimal preparation or damage.

  20. "Carbo-aromaticity" and novel carbo-aromatic compounds.

    PubMed

    Cocq, Kévin; Lepetit, Christine; Maraval, Valérie; Chauvin, Remi

    2015-09-21

    While the concept of aromaticity is being more and more precisely delineated, the category of "aromatic compounds" is being more and more expanded. This is illustrated by an introductory highlight of the various types of "aromaticity" previously invoked, and by a focus on the recently proposed "aromatic character" of the "two-membered rings" of the acetylene and butatriene molecules. This serves as a general foundation for the definition of "carbo-aromaticity", the relevance of which is surveyed through recent results in the synthetic, physical, and theoretical chemistry of carbo-mers and in particular macrocyclic-polycyclic representatives constituting a natural family of "novel aromatic compounds". With respect to their parent molecules, carbo-mers are constitutionally defined as "carbon-enriched", and can also be functionally regarded as "π-electron-enriched". This is exemplified by recent experimental and theoretical results on functional, aromatic, rigid, σ,π-macrocyclic carbo-benzene archetypes of various substitution patterns, with emphasis on the quadrupolar pattern. For the purpose of comparison, several types of non-aromatic references of carbo-benzenes are then considered, i.e. freely rotating σ,π-acyclic carbo-n-butadienes and flexible σ-cyclic, π-acyclic carbo-cyclohexadienes, and to "pro-aromatic" congeners, i.e. rigid σ,π-macrocyclic carbo-quinoids. It is shown that functional carbo-mers are entering the field of "molecular materials" for properties such as linear or nonlinear optical properties (e.g. dichromism and two-photon absorption) and single molecule conductivity. Since total or partial carbo-mers of aromatic carbon-allotropes of infinite size such as graphene (graphynes and graphdiynes) and graphite ("graphitynes") have long been addressed at the theoretical or conceptual level, recent predictive advances on the electrical, optical and mechanical properties of such carbo-materials are surveyed. Very preliminary experimental results

  1. Terahertz Spectroscopy of Biochars and Related Aromatic Compounds

    NASA Astrophysics Data System (ADS)

    Lepodise, L. M.; Horvat, J.; Lewis, R. A.

    2016-12-01

    A recent application of terahertz spectroscopy is to biochar, the agricultural charcoal produced by pyrolysis of various organic materials. Biochars simultaneously improve soil fertility and assist in carbon sequestration. Terahertz spectroscopy allows different biochars to be distinguished. However, the origin of the absorption features observed has not been clear. Given that biochar-based fertilizers are rich in aromatic compounds, we have investigated simple aromatic compounds as an approach to unravelling the complex biochar spectrum.

  2. Water-soluble constituents of caraway: aromatic compound, aromatic compound glucoside and glucides.

    PubMed

    Matsumura, Tetsuko; Ishikawa, Toru; Kitajima, Junichi

    2002-10-01

    From the water-soluble portion of the methanolic extract of caraway (fruit of Carum carvi L.), an aromatic compound, an aromatic compound glucoside and a glucide were isolated together with 16 known compounds. Their structures were clarified as 2-methoxy-2-(4'-hydroxyphenyl)ethanol, junipediol A 2-O-beta-D-glucopyranoside and L-fucitol, respectively.

  3. Prediction of seawater solubility of aromatic compounds

    SciTech Connect

    Hashimoto, Y.; Tokura, K.; Kishi, H.; Strachan, W.M.J.

    1984-01-01

    The salting-out effect by seawater constituents on the water solubilities of 11 aromatic compounds, anthracene, pyrene, phenanthrene, biphenyl, naphthalene, p-nitrotoluene, p-toluidine, o-nitrophenol, m-nitrophenol, p-nitrophenol and phenol was investigated. A best fit equation for the salting-out parameters, K, and distilled water solubilities, S/sub 0/, at 20/sup 0/C was found to be K = -0.0298 log S/sub 0/ + 0.114. Seawater solubilities, S, predicted for solutions of ionic strength, I, using the equation log S = (0.0298 I + 1)logS/sub 0/ - 0.114 I were in agreement with observed values within 13% and there were no significant differences between values from the Pacific Ocean seawater and those from 35% NaCl solutions. It was concluded that dissolved organic matter in seawater had an insignificant effect for the test chemicals.

  4. Nucleophilic fluorination of aromatic compounds

    SciTech Connect

    Satyamurthy, Nagichettiar; Barrio, Jorge R

    2014-03-18

    Iodylbenzene derivatives substituted with electron donating as well as electron withdrawing groups on the aromatic ring are used as precursors in aromatic nucleophilic substitution reactions. The iodyl group (IO.sub.2) is regiospecifically substituted by nucleophilic fluoride to provide the corresponding fluoroaryl derivatives. No-carrier-added [F-18]fluoride ion derived from anhydrous [F-18](F/Kryptofix, [F-18]CsF or a quaternary ammonium fluoride (e.g., Me.sub.4NF, Et.sub.4NF, n-Bu.sub.4NF, (PhCH.sub.2).sub.4NF) exclusively substitutes the iodyl moiety in these derivatives and provides high specific activity F-18 labeled fluoroaryl analogs. Iodyl derivatives of a benzothiazole analog and 6-iodyl-L-dopa derivatives have been synthesized as precursors and have been used in the preparation of no-carrier-added [F-18]fluorobenzothiazole as well as 6-[F-18]fluoro-L-dopa.

  5. Production of aromatic compounds in bacteria.

    PubMed

    Gosset, Guillermo

    2009-12-01

    The aromatic class of chemicals includes a large number of industrially important products. In bacteria and plants, the shikimate pathway and related biosynthetic pathways are a source of aromatic compounds having commercial value. Bacterial strains for the production of aromatic compounds from simple carbon sources as raw material have been generated by applying metabolic engineering and random/combinatorial strategies that modify central metabolism, aromatic biosynthetic pathways, transport, and regulatory functions. These strategies are complemented with heterologous gene expression and protein engineering. Engineered Escherichia coli and Pseudomonas putida strains are enabling the development of sustainable processes for the manufacture of 2-phenylethanol, p-hydroxycinnamic acid, p-hydroxystyrene, p-hydroxybenzoate, anthranilate, and cyclohexadiene-transdiols, among other useful chemicals.

  6. Determination of descriptors for polycyclic aromatic hydrocarbons and related compounds by chromatographic methods and liquid-liquid partition in totally organic biphasic systems.

    PubMed

    Ariyasena, Thiloka C; Poole, Colin F

    2014-09-26

    Retention factors on several columns and at various temperatures using gas chromatography and from reversed-phase liquid chromatography on a SunFire C18 column with various mobile phase compositions containing acetonitrile, methanol and tetrahydrofuran as strength adjusting solvents are combined with liquid-liquid partition coefficients in totally organic biphasic systems to calculate descriptors for 23 polycyclic aromatic hydrocarbons and eighteen related compounds of environmental interest. The use of a consistent protocol for the above measurements provides descriptors that are more self consistent for the estimation of physicochemical properties (octanol-water, air-octanol, air-water, aqueous solubility, and subcooled liquid vapor pressure). The descriptor in this report tend to have smaller values for the L and E descriptors and random differences in the B and S descriptors compared with literature sources. A simple atom fragment constant model is proposed for the estimation of descriptors from structure for polycyclic aromatic hydrocarbons. The new descriptors show no bias in the prediction of the air-water partition coefficient for polycyclic aromatic hydrocarbons unlike the literature values.

  7. Amino Acids, Aromatic Compounds, and Carboxylic Acids: How Did They Get Their Common Names?

    ERIC Educational Resources Information Center

    Leung, Sam H.

    2000-01-01

    Surveys the roots of the common names of organic compounds most likely to be encountered by undergraduate organic chemistry students. Includes information for 19 amino acids, 17 aromatic compounds, and 21 carboxylic acids. (WRM)

  8. Contributions of Selected Biogenic and Aromatic Compounds to the Formation of Tropospheric Secondary Organic Aerosol over Several Sites in the United States

    NASA Astrophysics Data System (ADS)

    Jaoui, M.; Kleindienst, T. E.; Lewandowski, M.; Offenberg, J. H.; Corse, E. W.; Gerald, T.; Edney, E.

    2009-12-01

    The National Exposure Research Laboratory of the U.S. Environmental Protection Agency recently undertook an integrated laboratory and field research effort to better understand the contribution of biogenic and aromatic hydrocarbons to the formation of submicron ambient secondary organic aerosol (SOA). In the laboratory, isoprene, α-pinene, β-caryophyllene, 1,3-butadiene, 2-methyl-3-buten-2-ol, benzene, and toluene were individually irradiated under a wide range of conditions in a photochemical reaction chamber in the presence of nitrogen oxide (NOx). These hydrocarbons are thought to contribute to ambient SOA formation. In field studies conducted in Research Triangle Park, NC; Duke Forest in Chapel Hill, NC; Atlanta, GA; Pensacola, FL; Birmingham and Centerville, AL; Riverside, CA; Detroit, MI; Northbrook, East St. Louis and Bondville, IL; and Cincinnati, OH, ambient PM2.5 samples were collected for various periods between 2003 and 2006. The SOA collected from these laboratory experiments and the ambient PM2.5 samples were analyzed for organic carbon (OC) concentration and for organic tracer compounds by GC-MS using BSTFA derivatization for their identification and quantification. An organic tracer-based method was developed for estimating ambient SOA concentrations from individual SOA precursors to allow an assessment of SOA model predictions with ambient data. The results show that several major reaction products detected in SOA formed in the laboratory photooxidations were among the major compounds detected in field samples, effectively connecting laboratory and field results. Using the tracer-based method, the contributions of isoprene and monoterpenes to SOA formation show strong seasonal dependencies. However, no clear seasonal variations were observed for sesquiterpenes and aromatic hydrocarbons. The contribution of 2-methyl-3-buten-2-ol to ambient SOA was found to be not only season dependent but also higher in locations dominated by conifers, which are

  9. Reaction of disubstituted aromatic compounds with styrene

    SciTech Connect

    Grushin, A.I.; Grigor'ev, V.V.; Prokof'ev, K.V.; Kozlova, N.M.

    1988-03-20

    Hydrocarbons of the 1,1-diphenylethane type were obtained by the reaction of styrene with various disubstituted derivatives of benzene in the presence of titanium tetrachloride. It was found that the yield of the desired compound depends on the strength of the electron-donating substituents and on steric factors in the aromatic ring.

  10. Pollution characteristics of volatile organic compounds, polycyclic aromatic hydrocarbons and phthalate esters emitted from plastic wastes recycling granulation plants in Xingtan Town, South China

    NASA Astrophysics Data System (ADS)

    Huang, De-Yin; Zhou, Shun-Gui; Hong, Wei; Feng, Wei-Feng; Tao, Liang

    2013-06-01

    With the aim to investigate the main pollution characteristics of exhaust gases emitted from plastic waste recycling granulation plants, mainly volatile organic compounds (VOCs), polycyclic aromatic hydrocarbons (PAHs) and phthalate esters (PAEs) were analyzed in Xingtan Town, the largest distribution center of plastic waste recycling in China. Both inside and outside the plants, the total concentrations of volatile monocyclic aromatic hydrocarbons (MAHs), PAHs and PAEs ranged from 2000 to 3000 μg m-3, 450 to 1200 ng m-3, and 200 to 1200 ng m-3, respectively. Their concentration levels inside the plants were higher than those outside the plants, and PAHs and PAEs were mainly distributed in the gas-phase. Notably, highly toxic benzo[a]pyrene (BaP) could be detected inside the plants, and harmful PAEs could be detected not only inside but also outside the plants, although PAEs are non-volatile. The exhaust gas composition and concentration were related to the plastic feedstock and granulation temperature.

  11. Chemotaxis of Azospirillum species to aromatic compounds

    SciTech Connect

    Lopez-de-Victoria, G.; Lovell, C.R. )

    1993-09-01

    Azospirillum sspeciesare free-living nitrogen fixing bacteria commonly found in soils and in association with plant roots, including important agricultural crops. Rhizosphere colonization my Azospirillum species has been shown to stimulate growth of a variety of plant species. Chemotaxis is one of the properties which may contribute to survival, rhizosphere colonization and the initiation of mutualistic interactions by Azospirillum species. This study evaluates the chemotactic responses of three Azospirillum stains to a variety of aromatic compounds:benzoate, catechol, 4-HB, and PCA. Results indicate that the same aromatic substance can elicit different chemotactic responses from different Azospirillum species, and that Azospirillum can detect aromatic substrates at concentrations similar to those they encounter naturally. 36 refs., 1 fig., 6 tabs.

  12. Urinary metabolites of a polycyclic aromatic hydrocarbon and volatile organic compounds in relation to lung cancer development in lifelong never smokers in the Shanghai Cohort Study

    PubMed Central

    Yuan, Jian-Min

    2014-01-01

    Exposures to polycyclic aromatic hydrocarbons (PAHs) from various environmental and occupational sources are considered a primary risk factor for lung cancer among lifelong never smokers, based largely on results from epidemiologic studies utilizing self-reported exposure information. Prospective, biomarker-based human studies on the role of PAH and other airborne carcinogens in the development of lung cancer among lifelong non-smokers have been lacking. We prospectively investigated levels of urinary metabolites of a PAH and volatile organic compounds in relation to lung cancer risk in a nested case–control study of 82 cases and 83 controls among lifelong never smokers of the Shanghai Cohort Study, a prospective cohort of 18 244 Chinese men aged 45–64 years at enrollment. We quantified three PAH metabolites: r-1,t-2,3,c-4-tetrahydroxy-1,2,3,4-tetrahydrophenanthrene (PheT), 3-hydroxyphenanthrene (3-OH-Phe) and total hydroxyphenanthrenes (total OH-Phe, the sum of 1-, 2-, 3- and 4-OH-Phe), as well as metabolites of the volatile organic compounds acrolein (3-hydroxypropyl mercapturic acid), benzene (S-phenyl mercapturic acid), crotonaldehyde (3-hydroxy-1-methylpropylmercapturic acid) and ethylene oxide (2-hydroxyethyl mercapturic acid). Urinary cotinine was also quantified to confirm non-smoking status. Compared with the lowest quartile, odds ratios (95% confidence intervals) for lung cancer risk for the highest quartile levels of PheT, 3-OH-Phe and total OH-Phe were 2.98 (1.13–7.87), 3.10 (1.12–7.75) and 2.59 (1.01–6.65) (all P trend < 0.05), respectively. None of the metabolites of the volatile organic compounds were associated with overall lung cancer risk. This study demonstrates a potentially important role of exposure to PAH in the development of lung cancer among lifelong never smokers. PMID:24148823

  13. 40 CFR 721.750 - Aromatic amine compound.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Aromatic amine compound. 721.750... Substances § 721.750 Aromatic amine compound. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance aromatic amine compound (PMN P-86-334) is subject to reporting...

  14. 40 CFR 721.875 - Aromatic nitro compound.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Aromatic nitro compound. 721.875... Substances § 721.875 Aromatic nitro compound. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance aromatic nitro compound (PMN P-86-335) is subject to reporting...

  15. 40 CFR 721.750 - Aromatic amine compound.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Aromatic amine compound. 721.750... Substances § 721.750 Aromatic amine compound. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance aromatic amine compound (PMN P-86-334) is subject to reporting...

  16. 40 CFR 721.875 - Aromatic nitro compound.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Aromatic nitro compound. 721.875... Substances § 721.875 Aromatic nitro compound. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance aromatic nitro compound (PMN P-86-335) is subject to reporting...

  17. 40 CFR 721.750 - Aromatic amine compound.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Aromatic amine compound. 721.750... Substances § 721.750 Aromatic amine compound. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance aromatic amine compound (PMN P-86-334) is subject to reporting...

  18. 40 CFR 721.875 - Aromatic nitro compound.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Aromatic nitro compound. 721.875... Substances § 721.875 Aromatic nitro compound. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance aromatic nitro compound (PMN P-86-335) is subject to reporting...

  19. 40 CFR 721.875 - Aromatic nitro compound.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Aromatic nitro compound. 721.875... Substances § 721.875 Aromatic nitro compound. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance aromatic nitro compound (PMN P-86-335) is subject to reporting...

  20. 40 CFR 721.750 - Aromatic amine compound.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Aromatic amine compound. 721.750... Substances § 721.750 Aromatic amine compound. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance aromatic amine compound (PMN P-86-334) is subject to reporting...

  1. Polycyclic aromatic hydrocarbons in oysters and sediments from the Yatsushiro Sea, Japan: comparison of potential risks among PAHs, dioxins and dioxin-like compounds in benthic organisms.

    PubMed

    Nakata, Haruhiko; Uehara, Kiriko; Goto, Yuta; Fukumura, Miki; Shimasaki, Hideyuki; Takikawa, Kiyoshi; Miyawaki, Takashi

    2014-01-01

    Polycyclic aromatic hydrocarbons (PAHs) were analyzed in oysters collected from 18 stations in the Yatsushiro Sea, western Japan. PAHs were detected in all samples analyzed, and the highest concentration (mean 230 ng/g wet weight) was found in oysters from Tanoura Bay. The high molecular weight PAHs to low molecular weight PAHs ratios in oysters from Tanoura Bay were higher than at other stations. Sediment samples collected from 42 stations in Tanoura Bay were analyzed for PAHs to understand their concentrations and distribution. Higher concentrations were found in sediment samples at two stations in the southern inner bay (mean 30,200 ng/g dry weight), which were approximately two orders of magnitude higher than at a reference site. These observations strongly suggest severe contamination and significant sources of PAHs in Tanoura Bay. Dioxins and dioxin-like compounds (PCDFs, and non- and mono-ortho coplanar PCBs) were analyzed in sediments from eight stations in Tanoura Bay. The concentrations were comparable to, or lower than, at the reference sites, suggesting that there are no specific sources of these compounds in this bay. PAH, dioxins and dioxin-like compounds DR-CALUX relative potencies (REP) were applied to the sediment concentrations to evaluate the potential for toxicological effects on benthic organisms. PAHs made the highest contribution to the total REP concentration, supplying 99% of the total REP, followed by PCDDs (0.18%), PCDFs (0.04%), and PCBs (<0.001%). In this area, PAHs appear to be the most important Ah receptor binding chemicals for potential toxicity to benthic species.

  2. Metabolism of aromatic compounds by Caulobacter crescentus

    SciTech Connect

    Chatterjee, D.K.; Bourquin, A.W.

    1987-05-01

    Cultures of Caulobacter crescentus were found to grow on a variety of aromatic compounds. Degradation of benzoate, p-hydroxybenzoate, and phenol was found to occur via ..beta..-ketoadipate. The induction of degradative enzymes such as benzoate 1,2-dioxygenase, the ring cleavage enzyme catechol 1,2-dioxygenase, and cis,cis-muconate lactonizing enzyme appeared similar to the control mechanism present in Pseudomonas spp. Both benzoate 1,2-dioxygenase and catechol 1,2-dioxygenase had stringent specificities, as revealed by their action toward substituted benzoates and substituted catechols, respectively.

  3. Bioremediation technologies for polycyclic aromatic hydrocarbon compounds

    SciTech Connect

    Alleman, B.C.; Leeson, A.

    1999-11-01

    Polycyclic aromatic hydrocarbon compounds (PAHs) are common and challenging contaminants that affect soil and sediments. Methods for treating PAHs have undergone change and refinement in the recent past, and this volume presents the latest trends in PAH remediation theory and practice. The papers in this volume cover topics ranging from the remediation of manufactured gas plant (MGP) sites to the remediation of sediments. The papers present lab and field studies, characterization studies, comparison studies, and descriptions of technologies ranging from composting to thermally enhanced bioremediation to fungal technologies and other innovative approaches.

  4. Solvent effects on chemical processes. I: Solubility of aromatic and heterocyclic compounds in binary aqueous-organic solvents.

    PubMed

    Khossravi, D; Connors, K A

    1992-04-01

    The standard free energy change (delta G0) for equilibrium dissolution in binary solvent mixtures is written as a sum of effects arising from solvent-solvent interactions (the general medium effect), solvent-solute interactions (the solvation effect), and solute-solute interactions (the intersolute effect). The general medium effect is given by gA gamma, where g is a curvature correction factor to the surface tension (gamma) and A is the molecular cavity surface area. A new feature is the definition of gamma to be that value appropriate to the equilibrium mean solvation shell composition. The solvation effect is modeled by stoichiometric stepwise competitive equilibria between the two solvent components for the solute. The intersolute effect includes the crystal energy and solution phase interactions. In this work, water was solvent component 1, and various miscible organic cosolvents served as solvent component 2. Relating all data to the fully aqueous solution gives an explicit expression for delta M delta G0, the solvent effect on the free energy change, as a function of the mole fractions x1 and x2. This function is a binding isotherm. Nonlinear regression leads (for a two-step solvation scheme) to estimates of the solvation exchange constants K1 and K2 and the parameter gA. This relationship was applied to 44 systems comprising combinations of 31 solutes and eight organic cosolvents. Curve fits were good to excellent, and most of the parameter estimates had physically reasonable magnitudes.

  5. Interstellar Polycyclic Aromatic Compounds and Astrophysics

    NASA Technical Reports Server (NTRS)

    Hudgins, Douglas M.; DeVincenzi, Donald (Technical Monitor)

    2001-01-01

    Over the past fifteen years, thanks to significant, parallel advancements in observational, experimental, and theoretical techniques, tremendous strides have been made in our understanding of the role polycyclic aromatic compounds (PAC) in the interstellar medium (ISM). Twenty years ago, the notion of an abundant population of large, carbon rich molecules in the ISM was considered preposterous. Today, the unmistakable spectroscopic signatures of PAC - shockingly large molecules by previous interstellar chemistry standards - are recognized throughout the Universe. In this paper, we will examine the interstellar PAC model and its importance to astrophysics, including: (1) the evidence which led to inception of the model; (2) the ensuing laboratory and theoretical studies of the fundamental spectroscopic properties of PAC by which the model has been refined and extended; and (3) a few examples of how the model is being exploited to derive insight into the nature of the interstellar PAC population.

  6. Aerobic biodegradation of trichloroethylene by microorganisms that degrade aromatic compounds

    SciTech Connect

    Lu, C.J.; Chang, C.Y.; Lee, C.M.

    1995-12-31

    Aerobic biodegradation of trichloroethylene (TCE) at an initial concentration of 80 mg/L with and without the presence of an aromatic compound was conducted with a series of batch reactors. The target aromatic compounds were benzene, toluene, and catechol. The aromatics-acclimated microorganisms were used as the cell source for the batch study. The results indicated that the presence of an aromatic compound was required to initiate the aerobic biodegradation of TCE by the aromatic-utilizing microorganisms. The addition of benzene or toluene initiated the removal of TCE. However, TCE removal was not proportional to the initial concentration of the aromatic compounds. The presence of an aromatic compound at an initial concentration of 5 mg/L resulted in better TCE removal in comparison with that at 1 or 20 mg/L. TCE removal was still significant after the depletion of the aromatic compound, but at a lower rate. The presence of catechol, an intermediate of the biodegradation of an aromatic compound, did not initiate the biodegradation of TCE by the catechol-utilizing microorganisms.

  7. Device for aqueous detection of nitro-aromatic compounds

    DOEpatents

    Reagen, W.K.; Schulz, A.L.; Ingram, J.C.; Lancaster, G.D.; Grey, A.E.

    1994-04-26

    This invention relates to a compact and portable detection apparatus for nitro-aromatic based chemical compounds, such as nitrotoluenes, dinitrotoluenes, and trinitrotoluene (TNT). The apparatus is based upon the use of fiber optics using filtered light. The preferred process of the invention relies upon a reflective chemical sensor and optical and electronic components to monitor a decrease in fluorescence when the nitro-aromatic molecules in aqueous solution combine and react with a fluorescent polycyclic aromatic compound. 4 figures.

  8. Device for aqueous detection of nitro-aromatic compounds

    DOEpatents

    Reagen, William K.; Schulz, Amber L.; Ingram, Jani C.; Lancaster, Gregory D.; Grey, Alan E.

    1994-01-01

    This invention relates to a compact and portable detection apparatus for ro-aromatic based chemical compounds, such as nitrotoluenes, dinitrotoluenes, and trinitrotoluene (TNT). The apparatus is based upon the use of fiber optics using filtered light. The preferred process of the invention relies upon a reflective chemical sensor and optical and electronic components to monitor a decrease in fluorescence when the nitro-aromatic molecules in aqueous solution combine and react with a fluorescent polycyclic aromatic compound.

  9. Interactions between manganese oxides and multiple-ringed aromatic compounds

    SciTech Connect

    Whelan, G.; Sims, R.C.

    1992-08-01

    Objective is to determine whether Mn reductive dissolution can oxidize multiple-ringed aromatics, such as PAHs, in an oxic environment? Research indicated that certain PAHs (eg, dihydrodiols and diones that form free-radical intermediates) are susceptible to oxidation and polymerization. Over 14 days, 83, 76, 54, 70, and 20% of the Mn was reduced by 2,3-, 1,3-, and 1,4-naphthalenediol, quinizarin, and 1,4-naphthoquinone, respectively. 100, 100, and 65% of the first three PAHs were oxidized, respectively. Aromatics with diol functional groups were more easily oxidized than those with only dione groups. Relatively insoluble compounds like quinizarin can be oxidized; insoluble ``humic-like`` material precipitated, indicating a polymerization-humification process. Results suggest that electron transfer/organic release from the oxide surface is the rate-limiting step.

  10. Interactions between manganese oxides and multiple-ringed aromatic compounds

    SciTech Connect

    Whelan, G. ); Sims, R.C. . Dept. of Civil and Environmental Engineering)

    1992-08-01

    Objective is to determine whether Mn reductive dissolution can oxidize multiple-ringed aromatics, such as PAHs, in an oxic environment Research indicated that certain PAHs (eg, dihydrodiols and diones that form free-radical intermediates) are susceptible to oxidation and polymerization. Over 14 days, 83, 76, 54, 70, and 20% of the Mn was reduced by 2,3-, 1,3-, and 1,4-naphthalenediol, quinizarin, and 1,4-naphthoquinone, respectively. 100, 100, and 65% of the first three PAHs were oxidized, respectively. Aromatics with diol functional groups were more easily oxidized than those with only dione groups. Relatively insoluble compounds like quinizarin can be oxidized; insoluble ''humic-like'' material precipitated, indicating a polymerization-humification process. Results suggest that electron transfer/organic release from the oxide surface is the rate-limiting step.

  11. Extraterrestrial Organic Compounds in Meteorites

    NASA Technical Reports Server (NTRS)

    Botta, Oliver; Bada, Jeffrey L.; Meyer, Michael (Technical Monitor)

    2003-01-01

    Many organic compounds or their precursors found in meteorites originated in the interstellar or circumstellar medium and were later incorporated into planetesimals during the formation of the solar system. There they either survived intact or underwent further processing to synthesize secondary products on the meteorite parent body. The most distinct feature of CI and CM carbonaceous chondrites, two types of stony meteorites, is their high carbon content (up to 3% of weight), either in the form of carbonates or of organic compounds. The bulk of the organic carbon consists of an insoluble macromolecular material with a complex structure. Also present is a soluble organic fraction, which has been analyzed by several separation and analytical procedures. Low detection limits can be achieved by derivatization of the organic molecules with reagents that allow for analysis by gas chromatography/mass spectroscopy and high performance liquid chromatography. The CM meteorite Murchison has been found to contain more than 70 extraterrestrial amino acids and several other classes of compounds including carboxylic acids, hydroxy carboxylic acids, sulphonic and phosphonic acids, aliphatic, aromatic and polar hydrocarbons, fullerenes, heterocycles as well as carbonyl compounds, alcohols, amines and amides. The organic matter was found to be enriched in deuterium, and distinct organic compounds show isotopic enrichments of carbon and nitrogen relative to terrestrial matter.

  12. [Efficient synthesis of multisubstituted aromatic compounds from phenol derivatives].

    PubMed

    Ikawa, Takashi

    2014-01-01

    Phenols are abundant in nature and diverse phenols are readily available commercially at low cost. Thus, phenols can be used as the raw materials for the synthesis of valuable multisubstituted aromatic compounds by the direct activation of phenolic hydroxyl groups (C-O bond activation), followed by substitutions with other substituents. Although the derivatization of phenolic hydroxyl groups to sulfonates, such as triflates, nonaflates, tosylates and mesylates, followed by the transition-metal-catalyzed coupling reactions has been extensively investigated for this purpose, the direct C-O bond activation of phenols for subsequent functional group transformation has been a long-standing challenge in modern organic synthesis. In this review, I have summarized my recent studies on the formal direct C-O bond activation of phenols using nonafluorobutanesulfonyl fluoride (NfF) for the synthesis of multisubstituted aromatics. I have focused on the dual use of NfF, a less expensive commercially available reagent, including the tentative formation of highly reactive nonaflates from phenols and the use of the liberated fluoride ion as a nucleophile to promote the reactions of nonaflates. The following four topics are discussed: 1) palladium-catalyzed coupling reactions of phenols, 2) novel preparation of benzynes from 2-silylphenols, 3) synthesis of fluorinated aromatic compounds via the formation of benzynes, and 4) Hiyama coupling of (tert-butyldimethylsilyl)arenes activated by internal phenolic hydroxyl groups.

  13. Participant-based monitoring of indoor and outdoor nitrogen dioxide, volatile organic compounds, and polycyclic aromatic hydrocarbons among MICA-Air households

    NASA Astrophysics Data System (ADS)

    Johnson, Markey M.; Williams, Ron; Fan, Zhihua; Lin, Lin; Hudgens, Edward; Gallagher, Jane; Vette, Alan; Neas, Lucas; Özkaynak, Halûk

    2010-12-01

    The Mechanistic Indicators of Childhood Asthma (MICA) study in Detroit, Michigan introduced a participant-based approach to reduce the resource burden associated with collection of indoor and outdoor residential air sampling data. A subset of participants designated as MICA-Air conducted indoor and outdoor residential sampling of nitrogen dioxide (NO 2), volatile organic compounds (VOCs), and polycyclic aromatic hydrocarbons (PAHs). This participant-based methodology was subsequently adapted for use in the Vanguard phase of the U.S. National Children's Study. The current paper examines residential indoor and outdoor concentrations of these pollutant species among health study participants in Detroit, Michigan. Pollutants measured under MICA-Air agreed well with other studies and continuous monitoring data collected in Detroit. For example, NO 2 and BTEX concentrations reported for other Detroit area monitoring were generally within 10-15% of indoor and outdoor concentrations measured in MICA-Air households. Outdoor NO 2 concentrations were typically higher than indoor NO 2 concentration among MICA-Air homes, with a median indoor/outdoor (I/O) ratio of 0.6 in homes that were not impacted by environmental tobacco smoke (ETS) during air sampling. Indoor concentrations generally exceeded outdoor concentrations for VOC and PAH species measured among non-ETS homes in the study. I/O ratios for BTEX species (benzene, toluene, ethylbenzene, and m/p- and o-xylene) ranged from 1.2 for benzene to 3.1 for toluene. Outdoor NO 2 concentrations were approximately 4.5 ppb higher on weekdays versus weekends. As expected, I/O ratios pollutants were generally higher for homes impacted by ETS. These findings suggest that participant-based air sampling can provide a cost-effective alternative to technician-based approaches for assessing indoor and outdoor residential air pollution in community health studies. We also introduced a technique for estimating daily concentrations at each

  14. Organic Compounds in Stardust

    NASA Technical Reports Server (NTRS)

    McKay, David S.; Clemett. Simon J.; Sandford, Scott A.; Nakamura-Messenger, Keiko; Hoerz, Fredrich

    2011-01-01

    The successful return of the STARDUST spacecraft provides a unique opportunity to investigate the nature and distribution of organic matter in cometary dust particles collected from Comet 81P/Wild-2. Analysis of individual cometary impact tracks in silica aerogel using the technique of two-step laser mass spectrometry (L2MS) demonstrates the presence of complex aromatic organic matter. While concerns remain as to the organic purity of the aerogel collection medium and the thermal effects associated with hypervelocity capture, the majority of the observed organic species appear indigenous to the impacting particles and are hence of cometary origin. While the aromatic fraction of the total organic matter present is believed to be small, it is notable in that it appears to be N-rich. Spectral analysis in combination with instrumental detection sensitivities suggest that N is incorporated predominantly in the form of aromatic nitriles (R-C N). While organic species in the STARDUST samples do share some similarities with those present in the matrices of carbonaceous chondrites, the closest match is found with stratospherically collected interplanetary dust particles. These findings are consistent with the notion that a fraction of interplanetary dust is of cometary origin. The presence of complex organic N-containing species in comets has astrobiological implications since comets are likely to have contributed to the prebiotic chemical inventory of both the Earth and Mars.

  15. POLYCYCLIC AROMATIC HYDROCARBONS (PAHS) AND OTHER SEMI-VOLATILE ORGANIC COMPOUNDS COLLECTED IN NEW YORK CITY IN RESPONSE TO THE EVENTS OF 9/11

    EPA Science Inventory

    Concentrations of over 60 non-polar semi-volatile and non-volatile organic compounds were measured in Lower Manhattan, New York using a high capacity Integrated Organic Gas and Particle Sampler, after the initial destruction of the World Trade Center. The results indicate that th...

  16. POLYCYCLIC AROMATIC HYDROCARBONS (PAHS) AND OTHER SEMI-VOLATILE ORGANIC COMPOUNDS COLLECTED IN NEW YORK CITY IN RESPONSE TO THE EVENTS OF 9/11

    EPA Science Inventory

    Concentrations of over 60 non-polar semi-volatile and non-volatile organic compounds were measured in Lower Manhattan, New York using a high capacity Integrated Organic Gas and Particle Sampler, after the initial destruction of the World Trade Center. The results indicate that ...

  17. POLYCYLIC AROMATIC HYDROCARBONS (PAHS) AND OTHER SEMI-VOLATILE ORGANIC COMPOUNDS COLLECTED IN NEW YORK CITY IN RESPONSE TO THE EVENTS OF 9/11

    EPA Science Inventory

    Concentrations of over 60 non-polar semi-volatile and non-volatile organic compounds were measured in Lower Manhattan, New York using a high capacity Integrated Organic Gas an Particle Sampler, after the initial destruction of the World Trade Center. The results indicate that t...

  18. Process for producing high purity aromatic compounds

    SciTech Connect

    Mayes, W.W.

    1980-05-20

    High-purity C7 and/or C8 aromatic hydrocarbons are produced by reforming a C7 or C8 full boiling carbon number naphtha feed fraction or combinations thereof under reforming conditions of sufficient severity to convert essentially all of the nonaromatic portion of the naphtha feed boiling in the C7 to C8 aromatic boiling range to C7 and/or C8 aromatics, and then separating the reformate by fractional distillation into highpurity fractions of C7 and/or C8 aromatic hydrocarbons. Preferably, the C7 and/or C8 full boiling carbon number naphtha feed fraction is reformed in a plurality of reformer reaction stages with increasingly more severe conditions in order to maximize the yield of the C7 and C8 aromatics.

  19. Assessing Uncertainty of Interspecies Correlation Estimation Models for Aromatic Compounds

    EPA Science Inventory

    We developed Interspecies Correlation Estimation (ICE) models for aromatic compounds containing 1 to 4 benzene rings to assess uncertainty in toxicity extrapolation in two data compilation approaches. ICE models are mathematical relationships between surrogate and predicted test ...

  20. Gas and Particulate Sampling of Airborne Polycyclic Aromatic Compounds

    SciTech Connect

    Lane, D.A.; Gundel, L.A.

    1995-10-01

    The denuder surfaces of the gas and particle (GAP) sampler (developed at the Atmospheric Environment Service of Environment Canada) have been modified by coating with XAD-4 resin, using techniques developed at Lawrence Berkeley National Laboratory (LBNL) for the lower capacity integrated organic vapor/particle sampler (IOVPS). The resulting high capacity integrated organic gas and particle sampler (IOGAPS) has been operated in ambient air at 16.7 L min{sup -1} for a 24-hour period in Berkeley, California, USA. Simultaneous measurements were made at the same collection rate with a conventional sampler that used a filter followed by two sorbent beds. Gas and particle partition measurements were determined for 13 polycyclic aromatic hydrocarbons (PAH) ranging from 2-ring to 6-ring species. The IOGAPS indicated a higher particle fraction of these compounds than did the conventional sampler, suggesting that the conventional sampler suffered from 'blow-off' losses from the particles collected on the filter.

  1. Aromatic metabolism of filamentous fungi in relation to the presence of aromatic compounds in plant biomass.

    PubMed

    Mäkelä, Miia R; Marinović, Mila; Nousiainen, Paula; Liwanag, April J M; Benoit, Isabelle; Sipilä, Jussi; Hatakka, Annele; de Vries, Ronald P; Hildén, Kristiina S

    2015-01-01

    The biological conversion of plant lignocellulose plays an essential role not only in carbon cycling in terrestrial ecosystems but also is an important part of the production of second generation biofuels and biochemicals. The presence of the recalcitrant aromatic polymer lignin is one of the major obstacles in the biofuel/biochemical production process and therefore microbial degradation of lignin is receiving a great deal of attention. Fungi are the main degraders of plant biomass, and in particular the basidiomycete white rot fungi are of major importance in converting plant aromatics due to their ability to degrade lignin. However, the aromatic monomers that are released from lignin and other aromatic compounds of plant biomass are toxic for most fungi already at low levels, and therefore conversion of these compounds to less toxic metabolites is essential for fungi. Although the release of aromatic compounds from plant biomass by fungi has been studied extensively, relatively little attention has been given to the metabolic pathways that convert the resulting aromatic monomers. In this review we provide an overview of the aromatic components of plant biomass, and their release and conversion by fungi. Finally, we will summarize the applications of fungal systems related to plant aromatics.

  2. Volatile Organic Compounds (VOCs)

    MedlinePlus

    ... United States Environmental Protection Agency Search Search Indoor Air Quality (IAQ) Share Facebook Twitter Google+ Pinterest Contact Us Volatile Organic Compounds' Impact on Indoor Air Quality On this page: Introduction Sources Health Effects Levels ...

  3. Bacterial Transcriptional Regulators for Degradation Pathways of Aromatic Compounds

    PubMed Central

    Tropel, David; van der Meer, Jan Roelof

    2004-01-01

    Human activities have resulted in the release and introduction into the environment of a plethora of aromatic chemicals. The interest in discovering how bacteria are dealing with hazardous environmental pollutants has driven a large research community and has resulted in important biochemical, genetic, and physiological knowledge about the degradation capacities of microorganisms and their application in bioremediation, green chemistry, or production of pharmacy synthons. In addition, regulation of catabolic pathway expression has attracted the interest of numerous different groups, and several catabolic pathway regulators have been exemplary for understanding transcription control mechanisms. More recently, information about regulatory systems has been used to construct whole-cell living bioreporters that are used to measure the quality of the aqueous, soil, and air environment. The topic of biodegradation is relatively coherent, and this review presents a coherent overview of the regulatory systems involved in the transcriptional control of catabolic pathways. This review summarizes the different regulatory systems involved in biodegradation pathways of aromatic compounds linking them to other known protein families. Specific attention has been paid to describing the genetic organization of the regulatory genes, promoters, and target operon(s) and to discussing present knowledge about signaling molecules, DNA binding properties, and operator characteristics, and evidence from regulatory mutants. For each regulator family, this information is combined with recently obtained protein structural information to arrive at a possible mechanism of transcription activation. This demonstrates the diversity of control mechanisms existing in catabolic pathways. PMID:15353566

  4. Polycyclic aromatic hydrocarbons (PAHs) and volatile organic compounds (VOCs) mitigation in the pyrolysis process of waste tires using CO₂ as a reaction medium.

    PubMed

    Kwon, Eilhann E; Oh, Jeong-Ik; Kim, Ki-Hyun

    2015-09-01

    Our work reported the CO2-assisted mitigation of PAHs and VOCs in the thermo-chemical process (i.e., pyrolysis). To investigate the pyrolysis of used tires to recover energy and chemical products, the experiments were conducted using a laboratory-scale batch-type reactor. In particular, to examine the influence of the CO2 in pyrolysis of a tire, the pyrolytic products including C1-5-hydrocarbons (HCs), volatile organic carbons (VOCs), and polycyclic aromatic hydrocarbons (PAHs) were evaluated qualitatively by gas chromatography (GC) with mass spectroscopy (MS) as well as with a thermal conductivity detector (TCD). The mass balance of the pyrolytic products under various pyrolytic conditions was established on the basis of their weight fractions of the pyrolytic products. Our experimental work experimentally validated that the amount of gaseous pyrolytic products increased when using CO2 as a pyrolysis medium, while substantially altering the production of pyrolytic oil in absolute content (7.3-17.2%) and in relative composition (including PAHs and VOCs). Thus, the co-feeding of CO2 in the pyrolysis process can be considered an environmentally benign and energy efficient process.

  5. Volatile compounds in dry dog foods and their influence on sensory aromatic profile.

    PubMed

    Koppel, Kadri; Adhikari, Koushik; Di Donfrancesco, Brizio

    2013-02-27

    The aim of this study was to determine volatile compounds in dry dog foods and their possible influence on sensory aromatic profile. Grain-free dry dog foods were compared to dry dog foods manufactured with grain, but also with different protein sources for their aromatic volatiles. Solid-phase microextraction/gas chromatography/mass spectrometry was used to determine the aromatic compounds present in the headspace of these samples. Partial Least Squares regression was performed to correlate the instrumental aromatic data with the descriptive aroma analysis data. A total of 54 aromatic compounds were tentatively identified in the dry dog food samples, with aldehydes and ketones being the most represented organic volatiles group. Grain-added products were on the average higher in total volatiles than grain-free products. Partial Least Squares regression analysis indicated possible connections with sensory aromatic profile and grain-added samples, such as rancid aroma and aldehydes, especially hexanal. The results of this study showed that dry dog foods are products with complex odor characteristics and that grain-free products are less aromatic.

  6. Degradation and assimilation of aromatic compounds by Corynebacterium glutamicum: another potential for applications for this bacterium?

    PubMed

    Shen, Xi-Hui; Zhou, Ning-Yi; Liu, Shuang-Jiang

    2012-07-01

    With the implementation of the well-established molecular tools and systems biology techniques, new knowledge on aromatic degradation and assimilation by Corynebacterium glutamicum has been emerging. This review summarizes recent findings on degradation of aromatic compounds by C. glutamicum. Among these findings, the mycothiol-dependent gentisate pathway was firstly discovered in C. glutamicum. Other important knowledge derived from C. glutamicum would be the discovery of linkages among aromatic degradation and primary metabolisms such as gluconeogenesis and central carbon metabolism. Various transporters in C. glutamicum have also been identified, and they play an essential role in microbial assimilation of aromatic compounds. Regulation on aromatic degradation occurs mainly at transcription level via pathway-specific regulators, but global regulator(s) is presumably involved in the regulation. It is concluded that C. glutamicum is a very useful model organism to disclose new knowledge of biochemistry, physiology, and genetics of the catabolism of aromatic compounds in high GC content Gram-positive bacteria, and that the new physiological properties of aromatic degradation and assimilation are potentially important for industrial applications of C. glutamicum.

  7. Transformations of aromatic compounds by nitrosomonas europaea

    SciTech Connect

    Keener, W.K.; Arp, D.J.

    1994-06-01

    The soil bacterium Nitrosomonas europaea is an obligate autotroph which uses O2 as an electron acceptor and ammonia as its sole natural energy source. The ubiquity of nitrifying bacteria may facilitate their use in bioremediation applications, but such applications will require a thorough knowledge of the substrate range of Ammonia monooxygenase (AMO) (catalyzing the oxidation of ammonia). This study extends the know substrate range of N. europaea to include alkylbenzenes, halobenzenes, and various N- and O-containing aromatics. Evidence is also presented that oxidation of p-cresol and ring-substituted benzylic alcohols to corresponding aldehydes joccures even in the absence of AMO activity. 33 refs., 7 figs.

  8. Microbial remediation of nitro-aromatic compounds: an overview.

    PubMed

    Kulkarni, Meenal; Chaudhari, Ambalal

    2007-10-01

    Nitro-aromatic compounds are produced by incomplete combustion of fossil fuel or nitration reactions and are used as chemical feedstock for synthesis of explosives, pesticides, herbicides, dyes, pharmaceuticals, etc. The indiscriminate use of nitro-aromatics in the past due to wide applications has resulted in inexorable environmental pollution. Hence, nitro-aromatics are recognized as recalcitrant and given Hazardous Rating-3. Although several conventional pump and treat clean up methods are currently in use for the removal of nitro-aromatics, none has proved to be sustainable. Recently, remediation by biological systems has attracted worldwide attention to decontaminate nitro-aromatics polluted sources. The incredible versatility inherited in microbes has rendered these compounds as a part of the biogeochemical cycle. Several microbes catalyze mineralization and/or non-specific transformation of nitro-aromatics either by aerobic or anaerobic processes. Aerobic degradation of nitro-aromatics applies mainly to mono-, dinitro-derivatives and to some extent to poly-nitro-aromatics through oxygenation by: (i) monooxygenase, (ii) dioxygenase catalyzed reactions, (iii) Meisenheimer complex formation, and (iv) partial reduction of aromatic ring. Under anaerobic conditions, nitro-aromatics are reduced to amino-aromatics to facilitate complete mineralization. The nitro-aromatic explosives from contaminated sediments are effectively degraded at field scale using in situ bioremediation strategies, while ex situ techniques using whole cell/enzyme(s) immobilized on a suitable matrix/support are gaining acceptance for decontamination of nitrophenolic pesticides from soils at high chemical loading rates. Presently, the qualitative and quantitative performance of biological approaches of remediation is undergoing improvement due to: (i) knowledge of catabolic pathways of degradation, (ii) optimization of various parameters for accelerated degradation, and (iii) design of microbe

  9. Fluoroalkylation of organic compounds

    NASA Astrophysics Data System (ADS)

    Mikhaylov, D. Yu; Budnikova, Yu H.

    2013-09-01

    Data on fluoroalkylation and perfluoroalkylation methods in organic synthesis are analyzed, summarized and described systematically. The most practically important properties of compounds with fluoroalkyl substituents are illustrated. The key trends and the potential of this field of organic chemistry are considered. Electrochemical syntheses of perfluoroalkyl derivatives that are inaccessible or experimentally difficult to prepare by regular chemical techniques are presented. Particular attention is paid to processes involving organometallic compounds as well as to prospects for the development of this field of research. The bibliography includes 226 references.

  10. Volatile and semivolatile organic compounds in laboratory ...

    EPA Pesticide Factsheets

    Speciated volatile organic compounds (VOCs) and organic fine particulate matter (PM2.5) mass emission factors were determined from laboratory peat fire experiments. Peat samples originated from two wildlife reserves located near the coast of North Carolina, U.S. Gas and particulate organics were quantified by gas chromatography/mass spectrometry and by high pressure liquid chromatography. Hazardous air pollutants (HAPs) accounted for a large fraction (~60 %) of the speciated VOC emissions from peat burning, including large contributions of acetaldehyde, formaldehyde, benzene, toluene, and chloromethane. Speciated organic PM2.5 mass was dominated by the following compound classes: organic acids, levoglucosan, n-alkanes, and n-alkenes. Emission factors for PM2.5 organic acids including n-alkanoic acids, n-alkenoic acids, n-alkanedioic acids, and aromatic acids were reported for the first time for peat burning, representing the largest fraction of organic carbon (OC) mass (11-12 %) of all speciated compound classes measured in this work. Levoglucosan contributed 2-3 % of the OC mass, while methoxyphenols represented 0.2-0.3 % of the OC mass on a carbon mass basis. Retene was the most abundant particulate phase polycyclic aromatic hydrocarbon. Total HAP VOC and particulate polycyclic aromatic hydrocarbon emissions from a 2008 peat wildfire in North Carolina were estimated, suggesting that peat fires can contribute a large fraction of state-wide HAP emissions. This p

  11. The oxidation degradation of aromatic compounds

    NASA Technical Reports Server (NTRS)

    Brezinsky, Kenneth; Glassman, Irvin

    1987-01-01

    A series of experiments were conducted which focused on understanding the role that the O atom addition to aromatic rings plays in the oxidation of benzene and toluene. Flow reactor studies of the oxidation of toluene gave an indication of the amount of O atoms available during an oxidation and the degree to which the O atom adds to the ring. Flow reactor studies of the oxidation of toluene and benzene to which NO2 was added, have shown that NO2 appears to suppress the formation of O atoms and consequently reduce the amount of phenols and cresols formed by O atom addition. A high temperature pyrolysis study of phenol has confirmed that the major decomposition products are carbon monoxide and cyclopentadiene. A preliminary value for the overall decomposition rate constant was also obtained.

  12. Organic compounds in meteorites

    NASA Technical Reports Server (NTRS)

    Anders, E.; Hayatsu, R.; Studier, M. H.

    1973-01-01

    The problem of whether organic compounds originated in meteorites as a primary condensate from a solar gas or whether they were introduced as a secondary product into the meteorite during its residence in a parent body is examined by initially attempting to reconstruct the physical conditions during condensation (temperature, pressure, time) from clues in the inorganic matrix of the meteorite. The condensation behavior of carbon under these conditions is then analyzed on the basis of thermodynamic calculations, and compounds synthesized in model experiments on the condensation of carbon are compared with those actually found in meteorites. Organic compounds in meteorites seem to have formed by catalytic reactions of carbon monoxide, hydrogen, and ammonia in the solar nebula at 360 to 400 K temperature and about 3 to 7.6 microtorr pressure. The onset of these reactions was triggered by the formation of suitable catalysts (magnetite, hydrated silicates) at these temperatures.

  13. Global atmospheric budget of simple monocyclic aromatic compounds

    NASA Astrophysics Data System (ADS)

    Cabrera-Perez, David; Taraborrelli, Domenico; Sander, Rolf; Pozzer, Andrea

    2016-06-01

    The global atmospheric budget and distribution of monocyclic aromatic compounds is estimated, using an atmospheric chemistry general circulation model. Simulation results are evaluated with an ensemble of surface and aircraft observations with the goal of understanding emission, production and removal of these compounds.Anthropogenic emissions provided by the RCP database represent the largest source of aromatics in the model (≃ 23 TgC year-1) and biomass burning from the GFAS inventory the second largest (≃ 5 TgC year-1). The simulated chemical production of aromatics accounts for ≃ 5 TgC year-1. The atmospheric burden of aromatics sums up to 0.3 TgC. The main removal process of aromatics is photochemical decomposition (≃ 27 TgC year-1), while wet and dry deposition are responsible for a removal of ≃ 4 TgC year-1.Simulated mixing ratios at the surface and elsewhere in the troposphere show good spatial and temporal agreement with the observations for benzene, although the model generally underestimates mixing ratios. Toluene is generally well reproduced by the model at the surface, but mixing ratios in the free troposphere are underestimated. Finally, larger discrepancies are found for xylenes: surface mixing ratios are not only overestimated but also a low temporal correlation is found with respect to in situ observations.

  14. Atmospheric Chemistry of Micrometeoritic Organic Compounds

    NASA Technical Reports Server (NTRS)

    Kress, M. E.; Belle, C. L.; Pevyhouse, A. R.; Iraci, L. T.

    2011-01-01

    Micrometeorites approx.100 m in diameter deliver most of the Earth s annual accumulation of extraterrestrial material. These small particles are so strongly heated upon atmospheric entry that most of their volatile content is vaporized. Here we present preliminary results from two sets of experiments to investigate the fate of the organic fraction of micrometeorites. In the first set of experiments, 300 m particles of a CM carbonaceous chondrite were subject to flash pyrolysis, simulating atmospheric entry. In addition to CO and CO2, many organic compounds were released, including functionalized benzenes, hydrocarbons, and small polycyclic aromatic hydrocarbons. In the second set of experiments, we subjected two of these compounds to conditions that simulate the heterogeneous chemistry of Earth s upper atmosphere. We find evidence that meteor-derived compounds can follow reaction pathways leading to the formation of more complex organic compounds.

  15. Organic compounds in meteorites

    NASA Technical Reports Server (NTRS)

    Lawless, J. G.

    1980-01-01

    Recent studies of carbonaceous chondrites provide evidence that certain organic compounds are indigenous and the result of an abiotic, chemical synthesis. The results of several investigators have established the presence of amino acids and precursors, mono- and dicarboxylic acids, N-heterocycles, and hydrocarbons as well as other compounds. For example, studies of the Murchison and Murray meteorites have revealed the presence of at least 40 amino acids with nearly equal abundances of D and L isomers. The population consists of both protein and nonprotein amino acids including a wide variety of linear, cyclic, and polyfunctional types. Results show a trend of decreasing concentration with increasing carbon number, with the most abundant being glycine (41 n Moles/g). These and other results to be reviewed provide persuasive support for the theory of chemical evolution and provide the only natural evidence for the protobiological subset of molecules from which life on earth may have arisen.

  16. Effects of halogenated aromatics/aliphatics and nitrogen(N)-heterocyclic aromatics on estimating the persistence of future pharmaceutical compounds using a modified QSAR model.

    PubMed

    Lim, Seung Joo; Fox, Peter

    2014-02-01

    The effects of halogenated aromatics/aliphatics and nitrogen(N)-heterocyclic aromatics on estimating the persistence of future pharmaceutical compounds were investigated using a modified half life equation. The potential future pharmaceutical compounds investigated were approximately 2000 pharmaceutical drugs currently undergoing the United States Food and Drug Administration (US FDA) testing. EPI Suite (BIOWIN) model estimates the fates of compounds based on the biodegradability under aerobic conditions. While BIOWIN considered the biodegradability of a compound only, the half life equation used in this study was modified by biodegradability, sorption and cometabolic oxidation. It was possible that the potential future pharmaceutical compounds were more accurately estimated using the modified half life equation. The modified half life equation considered sorption and cometabolic oxidation of halogenated aromatic/aliphatics and nitrogen(N)-heterocyclic aromatics in the sub-surface, while EPI Suite (BIOWIN) did not. Halogenated aliphatics in chemicals were more persistent than halogenated aromatics in the sub-surface. In addition, in the sub-surface environment, the fates of organic chemicals were much more affected by halogenation in chemicals than by nitrogen(N)-heterocyclic aromatics.

  17. 40 CFR 721.9620 - Aromatic sulfonic acid compound with amine.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Aromatic sulfonic acid compound with... Specific Chemical Substances § 721.9620 Aromatic sulfonic acid compound with amine. (a) Chemical substance... aromatic sulfonic acid compound with amine (PMN P-93-832) is subject to reporting under this section...

  18. 40 CFR 721.9620 - Aromatic sulfonic acid compound with amine.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Aromatic sulfonic acid compound with... Specific Chemical Substances § 721.9620 Aromatic sulfonic acid compound with amine. (a) Chemical substance... aromatic sulfonic acid compound with amine (PMN P-93-832) is subject to reporting under this section...

  19. 40 CFR 721.9620 - Aromatic sulfonic acid compound with amine.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Aromatic sulfonic acid compound with... Specific Chemical Substances § 721.9620 Aromatic sulfonic acid compound with amine. (a) Chemical substance... aromatic sulfonic acid compound with amine (PMN P-93-832) is subject to reporting under this section...

  20. 40 CFR 721.9620 - Aromatic sulfonic acid compound with amine.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Aromatic sulfonic acid compound with... Specific Chemical Substances § 721.9620 Aromatic sulfonic acid compound with amine. (a) Chemical substance... aromatic sulfonic acid compound with amine (PMN P-93-832) is subject to reporting under this section...

  1. 40 CFR 721.9620 - Aromatic sulfonic acid compound with amine.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Aromatic sulfonic acid compound with... Specific Chemical Substances § 721.9620 Aromatic sulfonic acid compound with amine. (a) Chemical substance... aromatic sulfonic acid compound with amine (PMN P-93-832) is subject to reporting under this section...

  2. 40 CFR 721.785 - Halogenated alkane aromatic compound (generic name).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Halogenated alkane aromatic compound... Specific Chemical Substances § 721.785 Halogenated alkane aromatic compound (generic name). (a) Chemical... as a halogenated alkane aromatic compound (PMN P-94-1747) is subject to reporting under this...

  3. 40 CFR 721.785 - Halogenated alkane aromatic compound (generic name).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Halogenated alkane aromatic compound... Specific Chemical Substances § 721.785 Halogenated alkane aromatic compound (generic name). (a) Chemical... as a halogenated alkane aromatic compound (PMN P-94-1747) is subject to reporting under this...

  4. 40 CFR 721.785 - Halogenated alkane aromatic compound (generic name).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Halogenated alkane aromatic compound... Specific Chemical Substances § 721.785 Halogenated alkane aromatic compound (generic name). (a) Chemical... as a halogenated alkane aromatic compound (PMN P-94-1747) is subject to reporting under this...

  5. 40 CFR 721.785 - Halogenated alkane aromatic compound (generic name).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Halogenated alkane aromatic compound... Specific Chemical Substances § 721.785 Halogenated alkane aromatic compound (generic name). (a) Chemical... as a halogenated alkane aromatic compound (PMN P-94-1747) is subject to reporting under this...

  6. 40 CFR 721.785 - Halogenated alkane aromatic compound (generic name).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Halogenated alkane aromatic compound... Specific Chemical Substances § 721.785 Halogenated alkane aromatic compound (generic name). (a) Chemical... as a halogenated alkane aromatic compound (PMN P-94-1747) is subject to reporting under this...

  7. Thermodynamic properties of organic iodine compounds

    NASA Astrophysics Data System (ADS)

    Richard, Laurent; Gaona, Xavier

    2011-11-01

    A critical evaluation has been made of the thermodynamic properties reported in the literature for 43 organic iodine compounds in the solid, liquid, or ideal gas state. These compounds include aliphatic, cyclic and aromatic iodides, iodophenols, iodocarboxylic acids, and acetyl and benzoyl iodides. The evaluation has been made on the basis of carbon number systematics and group additivity relations, which also allowed to provide estimates of the thermodynamic properties of those compounds for which no experimental data were available. Standard molal thermodynamic properties at 25 °C and 1 bar and heat capacity coefficients are reported for 13 crystalline, 29 liquid, and 39 ideal gas organic iodine compounds, which can be used to calculate the corresponding properties as a function of temperature and pressure. Values derived for the standard molal Gibbs energy of formation at 25 °C and 1 bar of these crystalline, liquid, and ideal gas organic iodine compounds have subsequently been combined with either solubility measurements or gas/water partition coefficients to obtain values for the standard partial molal Gibbs energies of formation at 25 °C and 1 bar of 32 aqueous organic iodine compounds. The thermodynamic properties of organic iodine compounds calculated in the present study can be used together with those for aqueous inorganic iodine species to predict the organic/inorganic speciation of iodine in marine sediments and petroleum systems, or in the near- and far-field of nuclear waste repositories.

  8. Amination of electrophilic aromatic compounds by vicarious nucleophilic substitution

    SciTech Connect

    Mitchell, Alexander R.; Pagoria, Philip F.; Schmidt, Robert D.

    2000-01-01

    The present invention relates to a process to aminate electrophilic aromatic compounds by vicarious nucleophilic substitution of hydrogen using quaternary hydrazinium salts. The use of trialkylhydrazinium halide, e.g., trimethylhydrazinium iodide, as well as hydroxylamine, alkoxylamines, and 4-amino-1,2,4-triazole to produce aminated aromatic structures, such as 1,3-diamino-2,4,6-trinitrobenzene (DATB), 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) and 3,5-diamino-2,4,6-trinitrotoluene (DATNT), is described. DATB and TATB are useful insensitive high explosives. TATB is also used for the preparation of benzenehexamine, a starting material for the synthesis of novel materials (optical imaging devices, liquid crystals, ferromagnetic compounds).

  9. Detection of Aromatic Nitro Compounds Using Preconcentrator and SPR Immunosensor

    NASA Astrophysics Data System (ADS)

    Onodera, Takeshi; Miyahara, Kazuhisa; Iwakura, Munehiro; Hayashi, Kenshi; Miura, Norio; Matsumoto, Kiyoshi; Toko, Kiyoshi

    In this study, we report the sensitive detection of aromatic nitro compounds using a surface plasmon resonance (SPR) immunosensor based on the indirect competitive method. The vapors from the substances were sampled with a preconcentrator developed here. The solutions of the sampled vapors were measured using SPR immunosensor. Three kinds of explosives such as 2,4-dinitrobenzene, 2,4-dinitrotoluene, and 2,4,6-trinitrotoluene were detected at 1 ppb. Sampling time at 1 l/min was 3 min. Total detection time was brought down to 5 min, which is relatively short for second scanning in landmine detection. Efforts are being made to integrate the SPR immunosensor and preconcentrator for rapid sensitive detection of nitro aromatic compounds under simulated field conditions.

  10. Photochemical reactions of aromatic compounds and the concept of the photon as a traceless reagent.

    PubMed

    Hoffmann, Norbert

    2012-11-01

    Electronic excitation significantly changes the reactivity of chemical compounds. Compared to ground state reactions, photochemical reactions considerably enlarge the application spectrum of a particular functional group in organic synthesis. Multistep syntheses may be simplified and perspectives for target oriented synthesis (TOS) and diversity oriented synthesis (DOS) are developed. New compound families become available or may be obtained more easily. In contrast to common chemical reagents, photons don't generate side products resulting from the transformation of a chemical reagent. Therefore, they are considered as a traceless reagent. Consequently, photochemical reactions play a central role in the methodology of sustainable chemistry. This aspect has been recognized since the beginning of the 20th century. As with many other photochemical transformations, photochemical reactions of aromatic, benzene-like compounds illustrate well the advantages in this context. Photochemical cycloadditions of aromatic compounds have been investigated for a long time. Currently, they are applied in various fields of organic synthesis. They are also studied in supramolecular structures. The phenomena of reactivity and stereoselectivity are investigated. During recent years, photochemical electron transfer mediated reactions are particularly focused. Such transformations have likewise been performed with aromatic compounds. Reactivity and selectivity as well as application to organic synthesis are studied.

  11. Correlations and adsorption mechanisms of aromatic compounds on a high heat temperature treated bamboo biochar.

    PubMed

    Yang, Kun; Yang, Jingjing; Jiang, Yuan; Wu, Wenhao; Lin, Daohui

    2016-03-01

    Adsorption of aromatic compounds, including polycyclic aromatic hydrocarbons, nitrobenzenes, phenols, and anilines, on a bamboo biochar produced at 700 °C (Ba700) was investigated with the mechanism discussion by isotherm fitting using the Polanyi-theory based Dubinin-Ashtakhov (DA) model. Correlations of adsorption capacity (Q(0)) of organic compounds with their molecular sizes and melting points, as well as correlations of adsorption affinity (E) with their solvatochromic parameters (i.e., π* and αm), on the biochar, were developed and indicating that adsorption is captured by the pore filling mechanism and derived from the hydrophobic effects of organic compounds and the forming of π-π electron donor-acceptor (EDA) interactions and hydrogen bonding interactions of organic molecules with surface sites of the biochar. The effects of organic molecular sizes and melting points on adsorption capacity are ascribed to the molecular sieving effect and the packing efficiency of the organic molecules in the biochar pores, respectively. These correlations can be used to quantitatively estimate the adsorption of organic compounds on biochars from their commonly physicochemical properties including solvatochromic parameters, melting points and molecular cross-sectional area. The prediction using these correlations is important for assessing the unknown adsorption behaviors of new organic compounds and also helpful to guide the surface modification of biochars and make targeted selection in the environmental applications of biochars as adsorbents.

  12. Biological Treatment of Groundwater Contaminated with Mixtures of Aromatic Compounds

    DTIC Science & Technology

    1993-03-01

    bioreactor to biodegrade chlorinated aromatic compounds. The site at Kelly AFB, TX is an abandoned waste storage area where the soil and groundwater is...scale submerged fixed- film bioreactors were tested with groundwater containing benzene, naphthalene, phenol, toluene, ortho and para- cresol , 2,4...strain JS150 could aerobically biodegrade complex mixtures of solvents if appropriate dissolved oxygen levels were maintained. After the initial 5 days

  13. Aromatic fluorine compounds. VII. Replacement of aromatic -Cl and -NO2 groups by -F

    USGS Publications Warehouse

    Finger, G.C.; Kruse, C.W.

    1956-01-01

    Replacement of -Cl by -F in aryl chlorides with potassium fluoride has been extended from 2,4-dinitrochlorobenzene to less activated halides by the use of non-aqueous solvents, especially dimethylformamide (DMF) and dimethyl sulfoxide (DMSO). Also replacement of -NO2 by -F in substituted nitrobenzenes was studied in DMF. As a direct result of this study, many aromatic fluorine compounds can now be obtained by a relatively simple synthetic route.

  14. (Anaerobic metabolism of aromatic compounds by phototrophic bacteria: Biochemical aspects)

    SciTech Connect

    Gibson, J.

    1989-01-01

    Two aspects of the work proposed have received major emphasis during the period since the grant was activated: isolation and characterization of transposon insertion mutants of Rhodopseudomonas palusrtis defective in phototrophic growth on aromatic compounds, and attempts to purify and characterize the Coenzyme A ligase enzyme involved in activating 4-hydroxybenzoate. The HPLC apparatus was installed in August, and calibration of columns both for metabolite and for protein separations has been initiated. A start has also been made on synthesis of Coenzyme A thioesters of compounds that are potential intermediates in the anaerobic degradation pathways. 1 tab.

  15. Microwave-assisted extraction of polycyclic aromatic compounds from coal.

    PubMed

    Kerst, M; Andersson, J T

    2001-08-01

    Microwave-assisted extraction (MAE) of polycyclic aromatic compounds (PACs) from coal is shown to give the same pattern of compounds as Soxhlet extraction. MAE requires only 10 mL solvent and 10 min extraction time whereas Soxhlet uses 200 mL and takes 24 h. Although the yields were lower, dichloromethane (DCM) was preferred to pyridine, N-methyl-2-pyrrolidone (NMP), and NMP with CS2 because the pattern of the PACs is shown to be independent of solvent and DCM is a much more convenient solvent to work with.

  16. Collection of gas and particle semi-volatile organic compounds: use of an oxidant denuder to minimize polycyclic aromatic hydrocarbons degradation during high-volume air sampling

    NASA Astrophysics Data System (ADS)

    Tsapakis, Manolis; Stephanou, Euripides G.

    The decomposition of polycyclic aromatic hydrocarbons (PAHs) by ozone in gas and particles, under high-volume sampling, was studied by using in parallel a conventional device and a device protected with an oxidant denuder. Three different sampling regimes—short and long sampling under high-ozone concentration and long sampling under low-ozone concentration—were selected at three representative sampling sites—a boreal forest, an urban site and a background marine station. The results of our study suggest that most PAHs are susceptible to ozone degradation under high ozone atmospheric concentrations (>50 ppbv) and long sampling times (>24 h). The highest concentration ratio of total PAHs between the two sampling systems was observed under collection conditions of long sampling and high ozone concentration, especially for the gaseous PAHs (up to 2.10). Conversely, long sampling time under low ozone concentration did not affect the concentration of collected PAHs in the gas or particle phase. The most reactive PAHs collected on filters and polyurethane foam were cyclopentane[ cd]pyrene and pyrene, respectively. The use of an oxidant denuder did not affect the PAH gas-particle distribution study. The slopes mr and the intercepts br of the regression between the log Kp and log P L0 did not substantially deviate between the two sampling devices.

  17. Process for reducing aromatic compounds in ethylenediamine with calcium

    DOEpatents

    Benkeser, R.A.; Laugal, J.A.; Rappa, A.

    1985-08-06

    Olefins are produced by containing an organic compound having at least one benzene ring with ethylenediamine and calcium metal, the calcium metal being used in large excess or alternatively in conjunction with an inert abrasive particulate substance. Substantially all of the organic compounds are converted to corresponding cyclic olefins, largely mono-olefins.

  18. Process for reducing aromatic compounds in ethylenediamine with calcium

    DOEpatents

    Benkeser, Robert A.; Laugal, James A.; Rappa, Angela

    1985-01-01

    Olefins are produced by containing an organic compound having at least one benzene ring with ethylenediamine and calcium metal, the calcium metal being used in large excess or alternatively in conjunction with an inert abrasive particulate substance. Substantially all of the organic compounds are converted to corresponding cyclic olefins, largely mono-olefins.

  19. Airborne Exposures to Polycyclic Aromatic Compounds Among Workers in Asphalt Roofing Manufacturing Facilities.

    PubMed

    Trumbore, David C; Osborn, Linda V; Johnson, Kathleen A; Fayerweather, William E

    2015-01-01

    We studied exposure of 151 workers to polycyclic aromatic compounds and asphalt emissions during the manufacturing of asphalt roofing products-including 64 workers from 10 asphalt plants producing oxidized, straight-run, cutback, and wax- or polymer-modified asphalts, and 87 workers from 11 roofing plants producing asphalt shingles and granulated roll roofing. The facilities were located throughout the United States and used asphalt from many refiners and crude oils. This article helps fill a gap in exposure data for asphalt roofing manufacturing workers by using a fluorescence technique that targets biologically active 4-6 ring polycyclic aromatic compounds and is strongly correlated with carcinogenic activity in animal studies. Worker exposures to polycyclic aromatic compounds were compared between manufacturing plants, at different temperatures and using different raw materials, and to important external benchmarks. High levels of fine limestone particulate in the plant air during roofing manufacturing increased polycyclic aromatic compound exposure, resulting in the hypothesis that the particulate brought adsorbed polycyclic aromatic compounds to the worker breathing zone. Elevated asphalt temperatures increased exposures during the pouring of asphalt. Co-exposures in these workplaces which act as confounders for both the measurement of total organic matter and fluorescence were detected and their influence discussed. Exposures to polycyclic aromatic compounds in asphalt roofing manufacturing facilities were lower than or similar to those reported in hot-mix paving application studies, and much below those reported in studies of hot application of built-up roofing asphalt. These relatively low exposures in manufacturing are primarily attributed to air emission controls in the facilities, and the relatively moderate temperatures, compared to built-up roofing, used in these facilities for oxidized asphalt. The exposure to polycyclic aromatic compounds was a very

  20. Analysis of preference for carbon source utilization among three strains of aromatic compounds degrading Pseudomonas.

    PubMed

    Karishma, M; Trivedi, Vikas D; Choudhary, Alpa; Mhatre, Akanksha; Kambli, Pranita; Desai, Jinal; Phale, Prashant S

    2015-10-01

    Soil isolates Pseudomonas putida CSV86, Pseudomonas aeruginosa PP4 and Pseudomonas sp. C5pp degrade naphthalene, phthalate isomers and carbaryl, respectively. Strain CSV86 displayed a diauxic growth pattern on phenylpropanoid compounds (veratraldehyde, ferulic acid, vanillin or vanillic acid) plus glucose with a distinct second lag-phase. The glucose concentration in the medium remained constant with higher cell respiration rates on aromatics and maximum protocatechuate 3,4-dioxygenase activity in the first log-phase, which gradually decreased in the second log-phase with concomitant depletion of the glucose. In strains PP4 and C5pp, growth profile and metabolic studies suggest that glucose is utilized in the first log-phase with the repression of utilization of aromatics (phthalate or carbaryl). All three strains utilize benzoate via the catechol 'ortho' ring-cleavage pathway. On benzoate plus glucose, strain CSV86 showed preference for benzoate over glucose in contrast to strains PP4 and C5pp. Additionally, organic acids like succinate were preferred over aromatics in strains PP4 and C5pp, whereas strain CSV86 co-metabolizes them. Preferential utilization of aromatics over glucose and co-metabolism of organic acids and aromatics are found to be unique properties of P. putida CSV86 as compared with strains PP4 and C5pp and this property of strain CSV86 can be exploited for effective bioremediation.

  1. Measurement and prediction of aromatic solute distribution coefficients for aqueous-organic solvent systems. Final report

    SciTech Connect

    Campbell, J.R.; Luthy, R.G.

    1984-06-01

    Experimental and modeling activities were performed to assess techniques for measurement and prediction of distribution coefficients for aromatic solutes between water and immiscible organic solvents. Experiments were performed to measure distribution coefficients in both clean water and wastewater systems, and to assess treatment of a wastewater by solvent extraction. The theoretical portions of this investigation were directed towards development of techniques for prediction of solute-solvent/water distribution coefficients. Experiments were performed to assess treatment of a phenolic-laden coal conversion wastewater by solvent extraction. The results showed that solvent extraction for recovery of phenolic material offered several wastewater processing advantages. Distribution coefficients were measured in clean water and wastewater systems for aromatic solutes of varying functionality with different solvent types. It was found that distribution coefficients for these compounds in clean water systems were not statistically different from distribution coefficients determined in a complex coal conversion process wastewater. These and other aromatic solute distribution coefficient data were employed for evaluation of modeling techniques for prediction of solute-solvent/water distribution coefficients. Eight solvents were selected in order to represent various chemical classes: toluene and benzene (aromatics), hexane and heptane (alkanes), n-octanol (alcohols), n-butyl acetate (esters), diisopropyl ether (ethers), and methylisobutyl ketone (ketones). The aromatic solutes included: nonpolar compounds such as benzene, toluene and naphthalene, phenolic compounds such as phenol, cresol and catechol, nitrogenous aromatics such as aniline, pyridine and aminonaphthalene, and other aromatic solutes such as naphthol, quinolinol and halogenated compounds. 100 references, 20 figures, 34 tables.

  2. Development of genetically engineered bacteria for production of selected aromatic compounds

    DOEpatents

    Ward, Thomas E.; Watkins, Carolyn S.; Bulmer, Deborah K.; Johnson, Bruce F.; Amaratunga, Mohan

    2001-01-01

    The cloning and expression of genes in the common aromatic pathway of E. coli are described. A compound for which chorismate, the final product of the common aromatic pathway, is an anabolic intermediate can be produced by cloning and expressing selected genes of the common aromatic pathway and the genes coding for enzymes necessary to convert chorismate to the selected compound. Plasmids carrying selected genes of the common aromatic pathway are also described.

  3. Characterizations of organic compounds in diesel exhaust particulates.

    PubMed

    Lim, Jaehyun; Lim, Cheolsoo; Kim, Sangkyun; Hong, Jihyung

    2015-08-01

    To characterize how the speed and load of a medium-duty diesel engine affected the organic compounds in diesel particle matter (PM) below 1 μm, four driving conditions were examined. At all four driving conditions, concentration of identifiable organic compounds in PM ultrafine (34-94 nm) and accumulation (94-1000 nm) modes ranged from 2.9 to 5.7 μg/m(3) and 9.5 to 16.4 μg/m(3), respectively. As a function of driving conditions, the non-oxygen-containing organics exhibited a reversed concentration trend to the oxygen-containing organics. The identified organic compounds were classified into eleven classes: alkanes, alkenes, alkynes, aromatic hydrocarbons, carboxylic acids, esters, ketones, alcohols, ethers, nitrogen-containing compounds, and sulfur-containing compounds. At all driving conditions, alkane class consistently showed the highest concentration (8.3 to 18.0 μg/m(3)) followed by carboxylic acid, esters, ketones and alcohols. Twelve polycyclic aromatic hydrocarbons (PAHs) were identified with a total concentration ranging from 37.9 to 174.8 ng/m(3). In addition, nine nitrogen-containing polycyclic aromatic compounds (NPACs) were identified with a total concentration ranging from 7.0 to 10.3 ng/m(3). The most abundant PAH (phenanthrene) and NPACs (7,8-benzoquinoline and 3-nitrophenanthrene) comprise a similar molecular (3 aromatic-ring) structure under the highest engine speed and engine load.

  4. Evaluation of anthropogenic secondary organic aerosol tracers from aromatic hydrocarbons

    NASA Astrophysics Data System (ADS)

    Al-Naiema, Ibrahim M.; Stone, Elizabeth A.

    2017-02-01

    Products of secondary organic aerosol (SOA) from aromatic volatile organic compounds (VOCs) - 2,3-dihydroxy-4-oxopentanoic acid, dicarboxylic acids, nitromonoaromatics, and furandiones - were evaluated for their potential to serve as anthropogenic SOA tracers with respect to their (1) ambient concentrations and detectability in PM2.5 in Iowa City, IA, USA; (2) gas-particle partitioning behaviour; and (3) source specificity by way of correlations with primary and secondary source tracers and literature review. A widely used tracer for toluene-derived SOA, 2,3-dihydroxy-4-oxopentanoic acid was only detected in the particle phase (Fp = 1) at low but consistently measurable ambient concentrations (averaging 0.3 ng m-3). Four aromatic dicarboxylic acids were detected at relatively higher concentrations (9.1-34.5 ng m-3), of which phthalic acid was the most abundant. Phthalic acid had a low particle-phase fraction (Fp = 0.26) likely due to quantitation interferences from phthalic anhydride, while 4-methylphthalic acid was predominantly in the particle phase (Fp = 0.82). Phthalic acid and 4-methylphthalic acid were both highly correlated with 2,3-dihydroxy-4-oxopentanoic acid (rs = 0.73, p = 0.003; rs = 0.80, p < 0.001, respectively), suggesting that they were derived from aromatic VOCs. Isophthalic and terephthalic acids, however, were detected only in the particle phase (Fp = 1), and correlations suggested association with primary emission sources. Nitromonoaromatics were dominated by particle-phase concentrations of 4-nitrocatechol (1.6 ng m-3) and 4-methyl-5-nitrocatechol (1.6 ng m-3) that were associated with biomass burning. Meanwhile, 4-hydroxy-3-nitrobenzyl alcohol was detected in a lower concentration (0.06 ng m-3) in the particle phase only (Fp = 1) and is known as a product of toluene photooxidation. Furandiones in the atmosphere have only been attributed to the photooxidation of aromatic hydrocarbons; however the substantial partitioning toward the gas phase

  5. Photocatabolism of aromatic compounds by the phototrophic purple bacterium Rhodomicrobium vannielii

    SciTech Connect

    Wright, G.E.; Madigan, M.T. )

    1991-07-01

    The phototrophic purple non-sulfur bacterium Thodomicrobium vannielii grew phototrophically (illuminated anaerobic conditions) on a variety of aromatic compounds (in the presence of CO{sub 2}). Benzoate was universally photocatabolized by all five strains of R. vannielii examined, and benzyl alcohol was photocatabolized by four of the five strains. Catabolism of benzyl alcohol by phototrophic bacteria has not been previously reported. Other aromatic substrates supporting reasonably good growth of R. vannielii strains were the methozylated benzoate derivatives vanillate (4-hydroxy-3-methoxybenzoate) and syringate (4-hydroxy-3,5-dimethoxybenzoate). However, catabolism of vanillate and syringate led to significant inhibition of bacteriochlorophyll synthesis in R. vannielii cells, eventually causing cultures to cease growing. No such effect on photopigment synthesis in cells grown on benzoate or benzyl alcohol was observed. Along with a handful of other species of anoxygenic phototrophic bacteria, the ability of the species R. vannielii to photocatabolize aromatic compounds indicates that this organism may also be ecologically significant as a consumer of aromatic derivatives in illuminated anaerobic habitats in nature.

  6. Nitrated Secondary Organic Tracer Compounds in Biomass Burning Smoke

    NASA Astrophysics Data System (ADS)

    Iinuma, Y.; Böge, O.; Gräfe, R.; Herrmann, H.

    2010-12-01

    Natural and human-initiated biomass burning releases large amounts of gases and particles into the atmosphere, impacting climate, environment and affecting public health. Several hundreds of compounds are emitted from biomass burning and these compounds largely originate from the pyrolysis of biopolymers such as lignin, cellulose and hemicellulose. Some of compounds are known to be specific to biomass burning and widely recognized as tracer compounds that can be used to identify the presence of biomass burning PM. Detailed chemical analysis of biomass burning influenced PM samples often reveals the presence compounds that correlated well with levoglucosan, a known biomass burning tracer compound. In particular, nitrated aromatic compounds correlated very well with levoglucosan, indicating that biomass burning as a source for this class of compounds. In the present study, we present evidence for the presence of biomass burning originating secondary organic aerosol (BSOA) compounds in biomass burning influenced ambient PM. These BSOA compounds are typically nitrated aromatic compounds that are produced in the oxidation of precursor compounds in the presence of NOx. The precursor identification was performed from a series of aerosol chamber experiments. m-Cresol, which is emitted from biomass burning at significant levels, is found to be a major precursor compounds for nitrated BSOA compounds found in the ambient PM. We estimate that the total concentrations of these compounds in the ambient PM are comparable to biogenic SOA compounds in winter months, indicating the BSOA contributes important amounts to the regional organic aerosol loading.

  7. Organic Compounds in Carbonaceous Meteorites

    NASA Technical Reports Server (NTRS)

    Cooper, Grorge

    2001-01-01

    Carbonaceous meteorites are relatively enriched in soluble organic compounds. To date, these compounds provide the only record available to study a range of organic chemical processes in the early Solar System chemistry. The Murchison meteorite is the best-characterized carbonaceous meteorite with respect to organic chemistry. The study of its organic compounds has related principally to aqueous meteorite parent body chemistry and compounds of potential importance for the origin of life. Among the classes of organic compounds found in Murchison are amino acids, amides, carboxylic acids, hydroxy acids, sulfonic acids, phosphonic acids, purines and pyrimidines (Table 1). Compounds such as these were quite likely delivered to the early Earth in asteroids and comets. Until now, polyhydroxylated compounds (polyols), including sugars (polyhydroxy aldehydes or ketones), sugar alcohols, sugar acids, etc., had not been identified in Murchison. Ribose and deoxyribose, five-carbon sugars, are central to the role of contemporary nucleic acids, DNA and RNA. Glycerol, a three-carbon sugar alcohol, is a constituent of all known biological membranes. Due to the relative lability of sugars, some researchers have questioned the lifetime of sugars under the presumed conditions on the early Earth and postulated other (more stable) compounds as constituents of the first replicating molecules. The identification of potential sources and/or formation mechanisms of pre-biotic polyols would add to the understanding of what organic compounds were available, and for what length of time, on the ancient Earth.

  8. Biodegradation of halogenated organic compounds.

    PubMed Central

    Chaudhry, G R; Chapalamadugu, S

    1991-01-01

    In this review we discuss the degradation of chlorinated hydrocarbons by microorganisms, emphasizing the physiological, biochemical, and genetic basis of the biodegradation of aliphatic, aromatic, and polycyclic compounds. Many environmentally important xenobiotics are halogenated, especially chlorinated. These compounds are manufactured and used as pesticides, plasticizers, paint and printing-ink components, adhesives, flame retardants, hydraulic and heat transfer fluids, refrigerants, solvents, additives for cutting oils, and textile auxiliaries. The hazardous chemicals enter the environment through production, commercial application, and waste. As a result of bioaccumulation in the food chain and groundwater contamination, they pose public health problems because many of them are toxic, mutagenic, or carcinogenic. Although synthetic chemicals are usually recalcitrant to biodegradation, microorganisms have evolved an extensive range of enzymes, pathways, and control mechanisms that are responsible for catabolism of a wide variety of such compounds. Thus, such biological degradation can be exploited to alleviate environmental pollution problems. The pathways by which a given compound is degraded are determined by the physical, chemical, and microbiological aspects of a particular environment. By understanding the genetic basis of catabolism of xenobiotics, it is possible to improve the efficacy of naturally occurring microorganisms or construct new microorganisms capable of degrading pollutants in soil and aquatic environments more efficiently. Recently a number of genes whose enzyme products have a broader substrate specificity for the degradation of aromatic compounds have been cloned and attempts have been made to construct gene cassettes or synthetic operons comprising these degradative genes. Such gene cassettes or operons can be transferred into suitable microbial hosts for extending and custom designing the pathways for rapid degradation of recalcitrant

  9. Method of upgrading oils containing hydroxyaromatic hydrocarbon compounds to highly aromatic gasoline

    DOEpatents

    Baker, E.G.; Elliott, D.C.

    1993-01-19

    The present invention is a multi-stepped method of converting an oil which is produced by various biomass and coal conversion processes and contains primarily single and multiple ring hydroxyaromatic hydrocarbon compounds to highly aromatic gasoline. The single and multiple ring hydroxyaromatic hydrocarbon compounds in a raw oil material are first deoxygenated to produce a deoxygenated oil material containing single and multiple ring aromatic compounds. Then, water is removed from the deoxygenated oil material. The next step is distillation to remove the single ring aromatic compounds as gasoline. In the third step, the multiple ring aromatics remaining in the deoxygenated oil material are cracked in the presence of hydrogen to produce a cracked oil material containing single ring aromatic compounds. Finally, the cracked oil material is then distilled to remove the single ring aromatics as gasoline.

  10. PERSISTENT PERFLUORINATED ORGANIC COMPOUNDS

    EPA Science Inventory

    Perfluorinated compounds (PFCs) have gained notoriety in the recent past. Global distribution of PFCs in wildlife, environmental samples and humans has sparked a recent increase in new investigations concerning PFCs. Historically PFCs have been used in a wide variety of consume...

  11. Application of BDD thin film electrode for electrochemical decomposition of heterogeneous aromatic compounds

    NASA Astrophysics Data System (ADS)

    Czupryniak, Justyna; Fabiańska, Aleksandra; Stepnowski, Piotr; Ossowski, Tadeusz; Bogdanowicz, Robert; Gnyba, Marcin; Siedlecka, Ewa M.

    2012-10-01

    The aim of the presented study is to investigate the applicability of electrochemical oxidation of aromatic compounds containing heteroatoms, e.g. waste from production of pesticides or pharmaceutics, at a borondoped diamond (BDD) electrode. The BDD electrodes were synthesized by microwave plasma enhanced chemical vapour deposition (MW PE CVD). Investigation of the electrode surface by optical microscopy and scanning electron microscopy (SEM) confirmed that the synthesized layer was continuous and formed a densely packed grain structure with an average roughness of less than 0 :5 μm. The influence of important electrochemical parameters: current density, kind of reactor, pH or mixing operation, on the efficiency of the oxidation was investigated. The fouling of electrode's surface caused by the deposition of organic material was observed during CV and galvanostatic experiments. At low current density the oxidation rate constant k was low, but the current efficiency was relatively high. The BDD can be used successfully to remove heterogeneous aromatic compounds existing either as molecules or cations. During 4 h of electrolysis 95% of aromatic compounds were electrochemically decomposed to mineral forms. It was observed that the influence of the initial pH on mineralization was marginal.

  12. Application of BDD thin film electrode for electrochemical decomposition of heterogeneous aromatic compounds

    NASA Astrophysics Data System (ADS)

    Czupryniak, Justyna; Fabiańska, Aleksandra; Stepnowski, Piotr; Ossowski, Tadeusz; Bogdanowicz, Robert; Gnyba, Marcin; Siedlecka, Ewa

    2012-10-01

    The aim of the presented study is to investigate the applicability of electrochemical oxidation of aromatic compounds containing heteroatoms, e.g. waste from production of pesticides or pharmaceutics, at a borondoped diamond (BDD) electrode. The BDD electrodes were synthesized by microwave plasma enhanced chemical vapour deposition (MW PE CVD). Investigation of the electrode surface by optical microscopy and scanning electron microscopy (SEM) confirmed that the synthesized layer was continuous and formed a densely packed grain structure with an average roughness of less than 0:5 μm. The influence of important electrochemical parameters: current density, kind of reactor, pH or mixing operation, on the efficiency of the oxidation was investigated. The fouling of electrode's surface caused by the deposition of organic material was observed during CV and galvanostatic experiments. At low current density the oxidation rate constant k was low, but the current efficiency was relatively high. The BDD can be used successfully to remove heterogeneous aromatic compounds existing either as molecules or cations. During 4 h of electrolysis 95% of aromatic compounds were electrochemically decomposed to mineral forms. It was observed that the influence of the initial pH on mineralization was marginal.

  13. The metabolism of aromatic compounds by Rhodopseudomonas palustris. A new, reductive, method of aromatic ring metabolism

    PubMed Central

    Dutton, P. L.; Evans, W. C.

    1969-01-01

    1. Rhodopseudomonas palustris grows both aerobically and photosynthetically on aromatic acids. p-Hydroxybenzoate and protocatechuate are able to support aerobic growth; these compounds are metabolized by the protocatechuate 4,5-oxygenase pathway. 2. The photoassimilation of benzoate and hydroxybenzoates and the effects of air and darkness on the photoassimilation of benzoate are described. 3. Evidence in conflict with the pathway previously proposed for the photometabolism of benzoate is discussed. 4. The photometabolism of benzoate is accomplished by a novel reductive pathway involving its reduction to cyclohex-1-ene-1-carboxylate, followed by hydration to 2-hydroxycyclohexanecarboxylate and after dehydrogenation to 2-oxocyclohexanecarboxylate further hydration results in ring-fission and the production of pimelate. 5. Attempts were made to prepare cell-free extracts capable of dissimilating benzoate. PMID:5807211

  14. Investigation of aromatic compound degradation under atmospheric conditions in the outdoor simulation chamber SAPHIR

    NASA Astrophysics Data System (ADS)

    Nehr, Sascha; Bohn, Birger; Rohrer, Franz; Tillmann, Ralf; Wegener, Robert; Dorn, Hans-Peter; Häseler, Rolf; Brauers, Theo; Wahner, Andreas

    2010-05-01

    Ozone is produced in the lower troposphere by the OH-initiated photooxidation of volatile organic compounds in the presence of NOx. Aromatic hydrocarbons from anthropogenic sources are a major contributor to the OH-reactivity and thus to ozone formation in urban areas [1]. Moreover, their degradation leads to formation of secondary organic aerosol. Aromatic compounds are therefore important trace constituents with regard to air quality. We will present the results of photooxidation experiments which were conducted in the atmospheric simulation chamber SAPHIR at Forschungszentrum Jülich. The experiments were designed to investigate the degradation mechanisms of benzene and p-xylene, which are among the most abundant aromatics in urban air samples. Benzene and p-xylene were selected because they have high structural symmetry which limits the number of potential isomers of secondary products. The experiments were performed under low-NOx-conditions (≤ 2 ppb). SAPHIR was equipped with instruments for the measurement of the parent aromatics and their major oxidation products, OH radicals, important radical precursors (O3, HONO, HCHO), photolysis frequencies and particulate matter. As shown in previous studies, simulation chamber data from the photooxidation of aromatics cannot be explained satisfactorily with current photochemistry mechanisms. For example the MCMv3.1 tends to overestimate the ozone-concentration and to underestimate the OH-concentration [2]. In this study, we will contrast model calculations with experimental results to check if similar discrepancies can be observed in SAPHIR and how they can be resolved. Based on the results of this preparatory study, further simulation chamber experiments with special emphasis on the radical budget are scheduled in 2010. References: [1] J. G. Calvert, R. Atkinson, K.H. Becker, R.M. Kamens, J.H. Seinfeld, T.J. Wallington, G. Yarwood: The mechanisms of atmospheric oxidation of aromatic hydrocarbons, Oxford University

  15. Method of upgrading oils containing hydroxyaromatic hydrocarbon compounds to highly aromatic gasoline

    DOEpatents

    Baker, Eddie G.; Elliott, Douglas C.

    1993-01-01

    The present invention is a multi-stepped method of converting an oil which is produced by various biomass and coal conversion processes and contains primarily single and multiple ring hydroxyaromatic hydrocarbon compounds to highly aromatic gasoline. The single and multiple ring hydroxyaromatic hydrocarbon compounds in a raw oil material are first deoxygenated to produce a deoxygenated oil material containing single and multiple ring aromatic compounds. Then, water is removed from the deoxygenated oil material. The next step is distillation to remove the single ring aromatic compouns as gasoline. In the third step, the multiple ring aromatics remaining in the deoxygenated oil material are cracked in the presence of hydrogen to produce a cracked oil material containing single ring aromatic compounds. Finally, the cracked oil material is then distilled to remove the single ring aromatics as gasoline.

  16. Formation of highly oxidized multifunctional organic compounds from anthropogenic volatile organic compounds

    NASA Astrophysics Data System (ADS)

    Molteni, Ugo; Baltensperger, Urs; Bianchi, Federico; Dommen, Josef; El Haddad, Imad; Frege, Carla; Klein, Felix; Rossi, Michel

    2016-04-01

    Recent studies have shown that highly oxidized multifunctional organic compounds (HOMs) from biogenic volatile organic compounds are important for new particle formation and early particle growth (e.g., Ehn et al., 2014). The formation mechanism has extensively been studied for biogenic precursors like alpha-pinene and was shown to proceed through an initial reaction with either OH radicals or ozone followed by radical propagation in a mechanism that involves O2 attack and hydrogen abstraction (Crounse et al., 2013). While the same processes can be expected for anthropogenic volatile organic compounds (AVOC), few studies have investigated these so far. Here we present the formation of HOMs from a variety of aromatic compounds after reaction with OH. All the compounds analyzed show HOM formation. AVOC could therefore play an important role in new particle formation events that have been detected in urban areas. References Crounse, J.D. et al., Autoxidation of organic compounds in the atmosphere. J. Phys.Chem. Lett. 4, 3513-3520 (2013). Ehn, M., et al. A large source of low-volatility secondary organic aerosol, Nature 506, 476-479 (2014).

  17. Biotechnological production of aromatic compounds of the extended shikimate pathway from renewable biomass.

    PubMed

    Lee, Jin-Ho; Wendisch, Volker F

    2016-11-18

    Aromatic chemicals that contain an unsaturated ring with alternating double and single bonds find numerous applications in a wide range of industries, e.g. paper and dye manufacture, as fuel additives, electrical insulation, resins, pharmaceuticals, agrochemicals, in food, feed and cosmetics. Their chemical production is based on petroleum (BTX; benzene, toluene, and xylene), but they can also be obtained from plants by extraction. Due to petroleum depletion, health compliance, or environmental issues such as global warming, the biotechnological production of aromatics from renewable biomass came more and more into focus. Lignin, a complex polymeric aromatic molecule itself, is a natural source of aromatic compounds. Many microorganisms are able to catabolize a plethora of aromatic compounds and interception of these pathways may lead to the biotechnological production of value-added aromatic compounds which will be discussed for Corynebacterium glutamicum. Biosynthesis of aromatic amino acids not only gives rise to l-tryptophan, L-tyrosine and l-phenylalanine, but also to aromatic intermediates such as dehydroshikimate or chorismate from which value-added aromatic compounds can be derived. In this review, we will summarize recent strategies for the biotechnological production of aromatic and related compounds from renewable biomass by Escherichia coli, Pseudomonas putida, C. glutamicum and Saccharomyces cerevisiae. In particular, we will focus on metabolic engineering of the extended shikimate pathway.

  18. Photochemical dimerization of organic compounds

    DOEpatents

    Crabtree, Robert H.; Brown, Stephen H.; Muedas, Cesar A.; Ferguson, Richard R.

    1992-01-01

    At least one of selectivity and reaction rate of photosensitized vapor phase dimerizations, including dehydrodimerizations, hydrodimerizations and cross-dimerizations of saturated and unsaturated organic compounds is improved by conducting the dimerization in the presence of hydrogen or nitrous oxide.

  19. Contribution of methyl group to secondary organic aerosol formation from aromatic hydrocarbon photooxidation

    NASA Astrophysics Data System (ADS)

    Li, Lijie; Qi, Li; Cocker, David R.

    2017-02-01

    The complete atmospheric oxidation pathways leading to secondary organic aerosol remain elusive for aromatic compounds including the role of methyl substitutes on oxidation. This study investigates the contribution of methyl group to Secondary Organic Aerosol (SOA) formation during the photooxidation of aromatic hydrocarbons under low NOx condition by applying methyl carbon labeled aromatic hydrocarbons ((13C2) m-xylene and (13C2) p-xylene). Particle and gas phase oxidation products are analyzed by a series of mass spectrometers (HR-TOF-AMS, PTR-MS and SIFT-MS). The methyl group carbon containing oxidation products partition to the particle-phase at a lower rate than the carbons originating from the aromatic ring as a result of ring opening reactions. Further, the methyl carbon in the original aromatic structure is at least 7 times less likely to be oxidized when forming products that partition to SOA than the aromatic ring carbon. Therefore, oxidation of the methyl group in xylenes exerts little impact on SOA formation in current study. This study provides supporting evidence for a recent finding - a similarity in the SOA formation and composition from aromatic hydrocarbons regardless of the alkyl substitutes.

  20. Biomedical Compounds from Marine organisms

    PubMed Central

    Jha, Rajeev Kumar; Zi-rong, Xu

    2004-01-01

    The Ocean, which is called the ‘mother of origin of life’, is also the source of structurally unique natural products that are mainly accumulated in living organisms. Several of these compounds show pharmacological activities and are helpful for the invention and discovery of bioactive compounds, primarily for deadly diseases like cancer, acquired immuno-deficiency syndrome (AIDS), arthritis, etc., while other compounds have been developed as analgesics or to treat inflammation, etc. The life-saving drugs are mainly found abundantly in microorganisms, algae and invertebrates, while they are scarce in vertebrates. Modern technologies have opened vast areas of research for the extraction of biomedical compounds from oceans and seas.

  1. Photoprotective compounds from marine organisms.

    PubMed

    Rastogi, Rajesh P; Richa; Sinha, Rajeshwar P; Singh, Shailendra P; Häder, Donat-P

    2010-06-01

    The substantial loss in the stratospheric ozone layer and consequent increase in solar ultraviolet radiation on the earth's surface have augmented the interest in searching for natural photoprotective compounds in organisms of marine as well as freshwater ecosystems. A number of photoprotective compounds such as mycosporine-like amino acids (MAAs), scytonemin, carotenoids and several other UV-absorbing substances of unknown chemical structure have been identified from different organisms. MAAs form the most common class of UV-absorbing compounds known to occur widely in various marine organisms; however, several compounds having UV-screening properties still need to be identified. The synthesis of scytonemin, a predominant UV-A-photoprotective pigment, is exclusively reported in cyanobacteria. Carotenoids are important components of the photosynthetic apparatus that serve both light-harvesting and photoprotective functions, either by direct quenching of the singlet oxygen or other toxic reactive oxygen species or by dissipating the excess energy in the photosynthetic apparatus. The production of photoprotective compounds is affected by several environmental factors such as different wavelengths of UVR, desiccation, nutrients, salt concentration, light as well as dark period, and still there is controversy about the biosynthesis of various photoprotective compounds. Recent studies have focused on marine organisms as a source of natural bioactive molecules having a photoprotective role, their biosynthesis and commercial application. However, there is a need for extensive work to explore the photoprotective role of various UV-absorbing compounds from marine habitats so that a range of biotechnological and pharmaceutical applications can be found.

  2. Correlation and prediction of adsorption capacity and affinity of aromatic compounds on carbon nanotubes.

    PubMed

    Wu, Wenhao; Yang, Kun; Chen, Wei; Wang, Wendi; Zhang, Jie; Lin, Daohui; Xing, Baoshan

    2016-01-01

    Adsorption of 22 nonpolar and polar aromatic compounds on 10 carbon nanotubes (CNTs) with various diameters, lengths and surface oxygen-containing group contents was investigated to develop predictive correlations for adsorption, using the isotherm fitting of Polanyi theory-based Dubinin-Ashtakhov (DA) model. Adsorption capacity of aromatic compounds on CNTs is negatively correlated with melting points of aromatic compounds, and surface oxygen-containing group contents and surface area ratios of mesopores to total pores of CNTs, but positively correlated with total surface area of CNTs. Adsorption affinity is positively correlated with solvatochromic parameters of aromatic compounds, independent of tube lengths and surface oxygen-containing group contents of CNTs, but negatively correlated with surface area ratios of mesopores to total pores of CNTs. The correlations of adsorption capacity and adsorption affinity with properties of both aromatic compounds and CNTs clearly have physical significance, can be used successfully with DA model to predict adsorption of aromatic compounds on CNTs from the well-known physiochemical properties of aromatic compounds (i.e., solvatochromic parameters, melting points) and CNTs (i.e., surface area and total acidic group contents), and thus can facilitate the environmental application of CNTs as sorbents and environmental risk assessment of both aromatic contaminants and CNTs.

  3. Inhibition of hydroxyl radical reaction with aromatics by dissolved natural organic matter

    USGS Publications Warehouse

    Lindsey, M.E.; Tarr, M.A.

    2000-01-01

    Reaction of aromatic compounds with hydroxyl radical is inhibited by dissolved natural organic matter (NOM). The degree of inhibition is significantly greater than that expected based on a simple model in which aromatic compound molecules bound to NOM are considered to be unreactive. In this study, hydroxyl radical was produced at steady-state concentrations using Fenton chemistry (H2O2 + Fe2+ ??? Fe3+ + HO- + HO??). Suwannee River fulvic acid and humic acid were used as NOM. The most likely mechanism for the observed inhibition is that hydroxyl radical formation occurs in microenvironmental sites remote from the aromatic compounds. In addition to changes in kinetics, pyrene hydroxyl radical reaction also exhibited a mechanistic change in the presence of fulvic acid. The mechanism changed from a reaction that was apparently firstorder in pyrene to one that was apparently secondorder in pyrene, indicating that pyrene self-reaction may have become the dominant mechanism in the presence of fulvic acid. Dissolved NOM causes significant changes in the rate and mechanism of hydroxyl radical degradation of aromatic compounds. Consequently, literature rate constants measured in pure water will not be useful for predicting the degradation of pollutants in environmental systems. The kinetic and mechanistic information in this study will be useful for developing improved degradation methods involving Fenton chemistry.Reaction of aromatic compounds with hydroxyl radical is inhibited by dissolved natural organic matter (NOM). The degree of inhibition is significantly greater than that expected based on a simple model in which aromatic compounds molecules bounds to NOM are considered to be unreactive. In this study, hydroxyl radical was produced at steady-state concentrations using Fenton chemistry (H2O2 + Fe2+ ??? Fe3+ + HO- + HO??). Suwannee River fulvic acid and humic acid were used as NOM. The most likely mechanisms for the observed inhibition is that hydroxyl radical

  4. Predicting adsorption of aromatic compounds by carbon nanotubes based on quantitative structure property relationship principles

    NASA Astrophysics Data System (ADS)

    Rahimi-Nasrabadi, Mehdi; Akhoondi, Reza; Pourmortazavi, Seied Mahdi; Ahmadi, Farhad

    2015-11-01

    Quantitative structure property relationship (QSPR) models were developed to predict the adsorption of aromatic compounds by carbon nanotubes (CNTs). Five descriptors chosen by combining self-organizing map and stepwise multiple linear regression (MLR) techniques were used to connect the structure of the studied chemicals with their adsorption descriptor (K∞) using linear and nonlinear modeling techniques. Correlation coefficient (R2) of 0.99 and root-mean square error (RMSE) of 0.29 for multilayered perceptron neural network (MLP-NN) model are signs of the superiority of the developed nonlinear model over MLR model with R2 of 0.93 and RMSE of 0.36. The results of cross-validation test showed the reliability of MLP-NN to predict the K∞ values for the aromatic contaminants. Molar volume and hydrogen bond accepting ability were found to be the factors much influencing the adsorption of the compounds. The developed QSPR, as a neural network based model, could be used to predict the adsorption of organic compounds by CNTs.

  5. Biodegradation of aromatic compounds: current status and opportunities for biomolecular approaches.

    PubMed

    Cao, Bin; Nagarajan, Karthiga; Loh, Kai-Chee

    2009-11-01

    Biodegradation can achieve complete and cost-effective elimination of aromatic pollutants through harnessing diverse microbial metabolic processes. Aromatics biodegradation plays an important role in environmental cleanup and has been extensively studied since the inception of biodegradation. These studies, however, are diverse and scattered; there is an imperative need to consolidate, summarize, and review the current status of aromatics biodegradation. The first part of this review briefly discusses the catabolic mechanisms and describes the current status of aromatics biodegradation. Emphasis is placed on monocyclic, polycyclic, and chlorinated aromatic hydrocarbons because they are the most prevalent aromatic contaminants in the environment. Among monocyclic aromatic hydrocarbons, benzene, toluene, ethylbenzene, and xylene; phenylacetic acid; and structurally related aromatic compounds are highlighted. In addition, biofilms and their applications in biodegradation of aromatic compounds are briefly discussed. In recent years, various biomolecular approaches have been applied to design and understand microorganisms for enhanced biodegradation. In the second part of this review, biomolecular approaches, their applications in aromatics biodegradation, and associated biosafety issues are discussed. Particular attention is given to the applications of metabolic engineering, protein engineering, and "omics" technologies in aromatics biodegradation.

  6. Facile Formation of Redox-Active Totally Organic Nanoparticles in Water by In Situ Reduction of Organic Precursors Stabilized through Aromatic-Aromatic Interactions by Aromatic Polyelectrolytes.

    PubMed

    Flores, Mario E; Garcés-Jerez, Pablo; Fernández, Daniel; Aros-Perez, Gustavo; González-Cabrera, Diego; Álvarez, Eduardo; Cañas, Ignacio; Oyarzun-Ampuero, Felipe; Moreno-Villoslada, Ignacio

    2016-11-01

    The formation of redox-active, totally organic nanoparticles in water is achieved following a strategy similar to that used to form metal nanoparticles. It is based on two fundamental concepts: i) complexation through aromatic-aromatic interactions of a water-soluble precursor aromatic molecule with polyelectrolytes bearing complementary charged aromatic rings, and ii) reduction of the precursor molecule to achieve stabilized nanoparticles. Thus, formazan nanoparticles are synthesized by reduction of a tetrazolium salt with ascorbic acid using polyelectrolytes bearing benzene sulfonate residues of high linear aromatic density, but cannot be formed in the presence of nonaromatic polyelectrolytes. The red colored nanoparticles are efficiently encapsulated in calcium alginate beads, showing macroscopic homogeneity. Bleaching kinetics with chlorine show linear rates on the order of tenths of milli-meters per minute. A linear behavior of the dependence of the rate of bleaching on the chlorine concentration is found, showing the potential of the nanoparticles for chlorine sensing.

  7. Quinones and Aromatic Chemical Compounds in Particulate Matter Induce Mitochondrial Dysfunction: Implications for Ultrafine Particle Toxicity

    PubMed Central

    Xia, Tian; Korge, Paavo; Weiss, James N.; Li, Ning; Venkatesen, M. Indira; Sioutas, Constantinos; Nel, Andre

    2004-01-01

    Particulate pollutants cause adverse health effects through the generation of oxidative stress. A key question is whether these effects are mediated by the particles or their chemical compounds. In this article we show that aliphatic, aromatic, and polar organic compounds, fractionated from diesel exhaust particles (DEPs), exert differential toxic effects in RAW 264.7 cells. Cellular analyses showed that the quinone-enriched polar fraction was more potent than the polycyclic aromatic hydrocarbon (PAH)–enriched aromatic fraction in O2•− generation, decrease of membrane potential (ΔΨm), loss of mitochondrial membrane mass, and induction of apoptosis. A major effect of the polar fraction was to promote cyclosporin A (CsA)–sensitive permeability transition pore (PTP) opening in isolated liver mitochondria. This opening effect is dependent on a direct effect on the PTP at low doses as well as on an effect on ΔΨm at high doses in calcium (Ca2+)-loaded mitochondria. The direct PTP effect was mimicked by redox-cycling DEP quinones. Although the aliphatic fraction failed to perturb mitochondrial function, the aromatic fraction increased the Ca2+ retention capacity at low doses and induced mitochondrial swelling and a decrease in ΔΨm at high doses. This swelling effect was mostly CsA insensitive and could be reproduced by a mixture of PAHs present in DEPs. These chemical effects on isolated mitochondria could be reproduced by intact DEPs as well as ambient ultrafine particles (UFPs). In contrast, commercial polystyrene nanoparticles failed to exert mitochondrial effects. These results suggest that DEP and UFP effects on the PTP and ΔΨm are mediated by adsorbed chemicals rather than the particles themselves. PMID:15471724

  8. Atmospheric plasma-driven catalysis for the low temperature decomposition of dilute aromatic compounds

    NASA Astrophysics Data System (ADS)

    Kim, Hyun-Ha; Ogata, Atsushi; Futamura, Shigeru

    2005-04-01

    The decomposition of volatile organic compounds (VOCs)—six aromatic compounds of benzene derivatives and formic acid—was investigated using a plasma-driven catalysis (PDC) system at atmospheric pressure. In the PDC reactor, the decomposition efficiency of VOCs was mostly determined by the specific input energy (SIE) and insensitivity to the gas hourly space velocity from 11 000 to 55 000 h-1. Formic acid (HCOOH) was formed as a common intermediate from the decomposition of the tested aromatic compounds. Formic acid was also found to be an important intermediate for CO2 formation. Except for styrene, all the tested VOCs indicated zero-order kinetics, which confirm the dominant role of the catalytic reaction in the decomposition of VOCs using the PDC reactor. A simple kinetic model represents well the observed zero-order kinetics with respect to the SIE. Unlike conventional plasma reactors, no correlation between the ionization potential and the decomposition was found with the PDC reactor. Continuous operation tests indicated stable performance without deterioration of catalytic activity over 150 h.

  9. Global inventory of volatile organic compound emissions from anthropogenic sources

    SciTech Connect

    Piccot, S.D.; Watson, J.J.; Jones, J.W.

    1992-01-01

    The paper discusses the development of a global inventory of anthropogenic volatile organic compound (VOC) emissions. It includes VOC estimates for seven classes of VOCs: paraffins, olefins, aromatics (benzene, toluene, xylene), formaldehyde, other aldehydes, other aromatics, and marginally reactive compounds. These classes represent general classes of VOC compounds that possess different chemical reactivities in the atmosphere. The inventory shows total global anthropogenic VOC emissions of about 110,000 Gg/yr, about 10% lower than global VOC inventories developed by other researchers. The study identifies the U.S. as the largest emitter (21% of the total global VOC), followed by the USSR, China, India, and Japan. Globally, fuel wood combustion and savanna burning were among the largest VOC emission sources, accounting for over 35% of the total global VOC emissions. The production and use of gasoline, refuse disposal activities, and organic chemical and rubber manufacturing were also found to be significant sources of global VOC emissions.

  10. Students' Categorizations of Organic Compounds

    ERIC Educational Resources Information Center

    Domin, Daniel S.; Al-Masum, Mohammad; Mensah, John

    2008-01-01

    Categorization is a fundamental psychological ability necessary for problem solving and many other higher-level cognitive tasks. In organic chemistry, students must establish groupings of different chemical compounds in order not only to solve problems, but also to understand course content. Classic models of categorization emphasize similarity as…

  11. Pressurized liquid extraction using water/isopropanol coupled with solid-phase extraction cleanup for semivolatile organic compounds, polycyclic aromatic hydrocarbons (PAH), and alkylated PAH homolog groups in sediment

    USGS Publications Warehouse

    Burkhardt, M.R.; Zaugg, S.D.; Burbank, T.L.; Olson, M.C.; Iverson, J.L.

    2005-01-01

    Polycyclic aromatic hydrocarbons (PAH) are recognized as environmentally relevant for their potential adverse effects on human and ecosystem health. This paper describes a method to determine the distribution of PAH and alkylated homolog groups in sediment samples. Pressurized liquid extraction (PLE), coupled with solid-phase extraction (SPE) cleanup, was developed to decrease sample preparation time, to reduce solvent consumption, and to minimize background interferences for full-scan GC-MS analysis. Recoveries from spiked Ottawa sand, environmental stream sediment, and commercially available topsoil, fortified at 1.5-15 ??g per compound, averaged 94.6 ?? 7.8%, 90.7 ?? 5.8% and 92.8 ?? 12.8%, respectively. Initial method detection limits for single-component compounds ranged from 20 to 302 ??g/kg, based on 25 g samples. Results from 28 environmental sediment samples, excluding homologs, show 35 of 41 compounds (85.4%) were detected in at least one sample with concentrations ranging from 20 to 100,000 ??g/kg. The most frequently detected compound, 2,6-dimethylnaphthalene, was detected in 23 of the 28 (82%) environmental samples with a concentration ranging from 15 to 907 ??g/kg. The results from the 28 environmental sediment samples for the homolog series showed that 27 of 28 (96%) samples had at least one homolog series present at concentrations ranging from 20 to 89,000 ??g/kg. The most frequently detected homolog series, C2-alkylated naphthalene, was detected in 26 of the 28 (93%) environmental samples with a concentration ranging from 25 to 3900 ??g/kg. Results for a standard reference material using dichloromethane Soxhlet-based extraction also are compared. ?? 2005 Elsevier B.V. All rights reserved.

  12. Process for removing halogenated aliphatic and aromatic compounds from petroleum products

    DOEpatents

    Googin, J.M.; Napier, J.M.; Travaglini, M.A.

    1983-09-20

    A process is described for removing halogenated aliphatic and aromatic compounds, e.g., polychlorinated biphenyls, from petroleum products by solvent extraction. The halogenated aliphatic and aromatic compounds are extracted from a petroleum product into a polar solvent by contacting the petroleum product with the polar solvent. The polar solvent is characterized by a high solubility for the extracted halogenated aliphatic and aromatic compounds, a low solubility for the petroleum product and considerable solvent power for polyhydroxy compound. The preferred polar solvent is dimethylformamide. A miscible compound, such as, water or a polyhydroxy compound, is added to the polar extraction solvent to increase the polarity of the polar extraction solvent. The halogenated aliphatic and aromatic compounds are extracted from the highly-polarized mixture of water or polyhydroxy compound and polar extraction solvent into a low polar or nonpolar solvent by contacting the water or polyhydroxy compound-polar solvent mixture with the low polar or nonpolar solvent. The halogenated aliphatic and aromatic compounds and the low polar or nonpolar solvent are separated by physical means, e.g., vacuum evaporation. The polar and nonpolar solvents are recovered from recycling. The process can easily be designed for continuous operation. Advantages of the process include that the polar solvent and a major portion of the nonpolar solvent can be recycled, the petroleum products are reclaimable and the cost for disposing of waste containing polychlorinated biphenyls is significantly reduced. 1 fig.

  13. Process for removing halogenated aliphatic and aromatic compounds from petroleum products

    DOEpatents

    Googin, John M.; Napier, John M.; Travaglini, Michael A.

    1983-01-01

    A process for removing halogenated aliphatic and aromatic compounds, e.g., polychlorinated biphenyls, from petroleum products by solvent extraction. The halogenated aliphatic and aromatic compounds are extracted from a petroleum product into a polar solvent by contacting the petroleum product with the polar solvent. The polar solvent is characterized by a high solubility for the extracted halogenated aliphatic and aromatic compounds, a low solubility for the petroleum product and considerable solvent power for polyhydroxy compound. The preferred polar solvent is dimethylformamide. A miscible compound, such as, water or a polyhydroxy compound, is added to the polar extraction solvent to increase the polarity of the polar extraction solvent. The halogenated aliphatic and aromatic compounds are extracted from the highly-polarized mixture of water or polyhydroxy compound and polar extraction solvent into a low polar or nonpolar solvent by contacting the water or polyhydroxy compound-polar solvent mixture with the low polar or nonpolar solvent. The halogenated aliphatic and aromatic compounds and the low polar or nonpolar solvent are separated by physical means, e.g., vacuum evaporation. The polar and nonpolar solvents are recovered from recycling. The process can easily be designed for continuous operation. Advantages of the process include that the polar solvent and a major portion of the nonpolar solvent can be recycled, the petroleum products are reclaimable and the cost for disposing of waste containing polychlorinated biphenyls is significantly reduced.

  14. Fluorescence spectroscopy of polynuclear aromatic compounds in environmental monitoring.

    PubMed

    Kumke, M U; Löhmannsröben, H G; Roch, T

    1995-06-01

    The occurrence of polynuclear aromatic compounds (PAC) in the environment and experimental techniques suitable for the detection of PAC in environmental compartments are briefly reviewed. The specific requirements for on-site andin situ environmental analysis are outlined. Particular emphasis is given to fluorescence spectroscopic techniques for the investigation of humic acid- and soil-containing samples. Some examples of studies in the literature on Shpol'skii and jet spectroscopy and on laser-induced fluorescence (OF) measurements of PAC and mineral oils are highlighted. Contaminants in the environment are usually encountered as multicomponent mixtures in very complex matrices. Total fluorescence analysis in combination with the chemometrical technique of rank annihilation factor analysis (RAFA) was employed for the evaluation of a six-component PAC mixture in toluene. It was shown that even in the presence of strong spectral overlap the qualitative identification of all compounds and the reliable quantification of five substances was possible. Results are presented from our stationary and time-resolved fluorescence investigations of the interactions between pyrene and humic acid in water. The Stern-Volmer analysis showed a significant effect of pH on the static quenching efficiency which can be explained by the pH-dependent macromolecular structure of humic acids. Preliminary results from studies of the deactivation of triplet PAC and quenching of delayed fluorescence by humic acid are reported. LIF measurements of mineral oils directly from soil surfaces and of a model oil in a soil column were performed with a fiber-optic coupled multichannel spectrometer. The fluorescence intensity/ concentration relationships were established for a crude and a fuel oil; the corresponding lower limits of detection (LOD) were determined to be 0.025 and 0.125% m/m (mass/mass percentages). These detection limits are compared with realistic oil contaminations of soils. In a soil

  15. Aliphatic, Cyclic, and Aromatic Organic Acids, Vitamins, and Carbohydrates in Soil: A Review

    PubMed Central

    Vranova, Valerie; Rejsek, Klement; Formanek, Pavel

    2013-01-01

    Organic acids, vitamins, and carbohydrates represent important organic compounds in soil. Aliphatic, cyclic, and aromatic organic acids play important roles in rhizosphere ecology, pedogenesis, food-web interactions, and decontamination of sites polluted by heavy metals and organic pollutants. Carbohydrates in soils can be used to estimate changes of soil organic matter due to management practices, whereas vitamins may play an important role in soil biological and biochemical processes. The aim of this work is to review current knowledge on aliphatic, cyclic, and aromatic organic acids, vitamins, and carbohydrates in soil and to identify directions for future research. Assessments of organic acids (aliphatic, cyclic, and aromatic) and carbohydrates, including their behaviour, have been reported in many works. However, knowledge on the occurrence and behaviour of D-enantiomers of organic acids, which may be abundant in soil, is currently lacking. Also, identification of the impact and mechanisms of environmental factors, such as soil water content, on carbohydrate status within soil organic matter remains to be determined. Finally, the occurrence of vitamins in soil and their role in biological and biochemical soil processes represent an important direction for future research. PMID:24319374

  16. Aliphatic, cyclic, and aromatic organic acids, vitamins, and carbohydrates in soil: a review.

    PubMed

    Vranova, Valerie; Rejsek, Klement; Formanek, Pavel

    2013-11-10

    Organic acids, vitamins, and carbohydrates represent important organic compounds in soil. Aliphatic, cyclic, and aromatic organic acids play important roles in rhizosphere ecology, pedogenesis, food-web interactions, and decontamination of sites polluted by heavy metals and organic pollutants. Carbohydrates in soils can be used to estimate changes of soil organic matter due to management practices, whereas vitamins may play an important role in soil biological and biochemical processes. The aim of this work is to review current knowledge on aliphatic, cyclic, and aromatic organic acids, vitamins, and carbohydrates in soil and to identify directions for future research. Assessments of organic acids (aliphatic, cyclic, and aromatic) and carbohydrates, including their behaviour, have been reported in many works. However, knowledge on the occurrence and behaviour of D-enantiomers of organic acids, which may be abundant in soil, is currently lacking. Also, identification of the impact and mechanisms of environmental factors, such as soil water content, on carbohydrate status within soil organic matter remains to be determined. Finally, the occurrence of vitamins in soil and their role in biological and biochemical soil processes represent an important direction for future research.

  17. Sorption of polar and nonpolar aromatic compounds to two humic acids with varied structural heterogeneity

    SciTech Connect

    Sun, H.Y.; Zhu, D.Q.; Mao, J.D.

    2008-12-15

    The major objective of the present study was to evaluate the correlation between structural nature of humic acids (HAs) and sorption affinity of organic compounds with varied polarity. We compared the sorption behavior of three aromatic compounds-nonpolar phenanthrene (PHEN) and 1,2,4,5-tetrachlorobenzene (TeCB) and highly polar 2,4-dichlorophenol (DCP)-to a solid-phase coal humic acid (CHA) and a soil humic acid (SHA) suspended in aqueous solution. The structural nature of HAs was characterized using elemental analysis, ultraviolet absorbance, diffusive reflectance Fourier-transform infrared, and solid-state C-13 nuclear magnetic resonance. The two tested HAs have very different structural properties: CHA consists primarily of poly(methylene)-rich aliphatics with high aromatic content and some COO/N-C=O but low polarity, while SHA consists of young materials of lignin, carbohydrates, and peptides with high polarity. In response to the structural heterogeneity of HAs, sorption of nonpolar and more hydrophobic solutes (PHEN, TeCB) to CHA is much greater than that to SHA because of the predominance of hydrophobic effects; however, disparities in sorption affinity between the two HAs become smaller for polar and less hydrophobic DCP because of the major role played by polar interactions. The influence of pH on the sorption of different solutes to the two HAs was also discussed. The results of the present work highlight the importance of structural heterogeneity of both solutes and HAs in the sorption process.

  18. Nitrogen oxides as dopants for the detection of aromatic compounds with ion mobility spectrometry.

    PubMed

    Gaik, Urszula; Sillanpää, Mika; Witkiewicz, Zygfryd; Puton, Jarosław

    2017-03-03

    Limits of detection (LODs) in ion mobility spectrometry (IMS) strictly depend on ionization of the analyte. Especially challenging is ionization of compounds with relatively low proton affinity (PA) such as aromatic compounds. To change the course of ion-molecule reactions and enhance the performance of the IMS spectrometer, substances called dopants are introduced into the carrier gas. In this work, we present the results of studies of detection using nitrogen oxides (NOx) dopants. Three aromatic compounds, benzene, toluene, toluene diisocyanate and, for comparison, two compounds with high PA, dimethyl methylphosphonate (DMMP) and triethyl phosphate (TEP), were selected as analytes. The influence of water vapour on these analyses was also studied. Experiments were carried out with a generator of gas mixtures that allowed for the simultaneous introduction of three substances into the carrier gas. The experiments showed that the use of NOx dopants significantly decreases LODs for aromatic compounds and does not affect the detection of compounds with high PA. The water vapour significantly disturbs the detection of aromatic compounds; however, doping with NOx allows to reduce the effect of humidity. Graphical Abstract Two possible ionization mechanisms of aromatic compounds in ion mobility spectrometry: proton transfer reaction and adduct formation.

  19. The Use of Modified Bentonite for Removal of Aromatic Organics from Contaminated Soil.

    PubMed

    Gitipour; Bowers; Bodocsi

    1997-12-15

    This study investigates the clay-aromatic interactions with a view to the use of bentonite clay for binding benzene, toluene, ethylbenzene, and o-xylene (BTEX compounds) in contaminated soils. BTEX compounds are the most toxic aromatic constituents of gasoline present in many underground storage tanks. Modified (organophilic) and ordinary bentonites are used to remove these organics. The organophilic bentonites are prepared by replacing the exchangeable inorganic cations present in bentonite particles with a quaternary ammonium salt. Various clay-to-soil ratios were applied to determine the efficiency of the modified bentonite in enhancing the cement-based solidification/stabilization (S/S) of BTEX contaminated soils. Toxicity characteristics leaching procedure (TCLP) tests were performed on soil samples to evaluate the leaching of the organics. In addition, X-ray diffraction analyses were conducted to assess the changes in the basal spacing of the clays as a result of their interaction with BTEX compounds. The findings of this study reveal that organophilic bentonite can act as a successful adsorbent for removing the aromatic organics from contaminated soil. Thus, this material is viable for enhancing the performance of cement-based S/S processes, as an adsorbent for petroleum spills, and for landfill liners and slurry walls. Copyright 1997 Academic Press.

  20. Bond cleavage of lignin model compounds into aromatic monomers using supported metal catalysts in supercritical water

    PubMed Central

    Yamaguchi, Aritomo; Mimura, Naoki; Shirai, Masayuki; Sato, Osamu

    2017-01-01

    More efficient use of lignin carbon is necessary for carbon-efficient utilization of lignocellulosic biomass. Conversion of lignin into valuable aromatic compounds requires the cleavage of C–O ether bonds and C–C bonds between lignin monomer units. The catalytic cleavage of C–O bonds is still challenging, and cleavage of C–C bonds is even more difficult. Here, we report cleavage of the aromatic C–O bonds in lignin model compounds using supported metal catalysts in supercritical water without adding hydrogen gas and without causing hydrogenation of the aromatic rings. The cleavage of the C–C bond in bibenzyl was also achieved with Rh/C as a catalyst. Use of this technique may greatly facilitate the conversion of lignin into valuable aromatic compounds. PMID:28387304

  1. Volatile and semivolatile organic compounds in laboratory peat fire emissions

    NASA Astrophysics Data System (ADS)

    George, Ingrid J.; Black, Robert R.; Geron, Chris D.; Aurell, Johanna; Hays, Michael D.; Preston, William T.; Gullett, Brian K.

    2016-05-01

    In this study, volatile and semi-volatile organic compound (VOCs and SVOCs) mass emission factors were determined from laboratory peat fire experiments. The peat samples originated from two National Wildlife Refuges on the coastal plain of North Carolina, U.S.A. Gas- and particle-phase organic compounds were quantified by gas chromatography-mass spectrometry and by high pressure liquid chromatography. Hazardous air pollutants (HAPs) accounted for a large fraction (∼60%) of the speciated VOC emissions from peat burning, including large contributions of acetaldehyde, formaldehyde, benzene, toluene, and chloromethane. In the fine particle mass (PM2.5), the following organic compound classes were dominant: organic acids, levoglucosan, n-alkanes, and n-alkenes. Emission factors for the organic acids in PM2.5 including n-alkanoic acids, n-alkenoic acids, n-alkanedioic acids, and aromatic acids were reported for the first time for peat burning, representing the largest fraction of organic carbon (OC) mass (11-12%) of all speciated compound classes measured in this work. Levoglucosan contributed to 2-3% of the OC mass, while methoxyphenols represented 0.2-0.3% of the OC mass on a carbon mass basis. Retene was the most abundant particulate phase polycyclic aromatic hydrocarbon (PAH). Total HAP VOC and particulate PAH emissions from a 2008 peat wildfire in North Carolina were estimated, suggesting that peat fires can contribute a large fraction of state-wide HAP emissions.

  2. The role of aromatic precursors in the formation of haloacetamides by chloramination of dissolved organic matter.

    PubMed

    Le Roux, Julien; Nihemaiti, Maolida; Croué, Jean-Philippe

    2016-01-01

    Water treatment utilities are diversifying their water sources and often rely on waters enriched in nitrogen-containing compounds (e.g., ammonia, organic nitrogen such as amino acids). The disinfection of waters exhibiting high levels of nitrogen has been associated with the formation of nitrogenous disinfection byproducts (N-DBPs) such as haloacetonitriles (HANs) and haloacetamides (HAcAms). While the potential precursors of HANs have been extensively studied, only few investigations are available regarding the nature of HAcAm precursors. Previous research has suggested that HAcAms are hydrolysis products of HANs. Nevertheless, it has been recently suggested that HAcAms can be formed independently, especially during chloramination of humic substances. When used as a disinfectant, monochloramine can also be a source of nitrogen for N-DBPs. This study investigated the role of aromatic organic matter in the formation of N-DBPs (HAcAms and HANs) upon chloramination. Formation kinetics were performed from various fractions of organic matter isolated from surface waters or treated wastewater effluents. Experiments were conducted with (15)N-labeled monochloramine ((15)NH2Cl) to trace the origin of nitrogen. N-DBP formation showed a two-step profile: (1) a rapid formation following second-order reaction kinetics and incorporating nitrogen atom originating from the organic matrix (e.g., amine groups); and (2) a slower and linear increase correlated with exposure to chloramines, incorporating inorganic nitrogen ((15)N) from (15)NH2Cl into aromatic moieties. Organic matter isolates showing high aromatic character (i.e., high SUVA) exhibited high reactivity characterized by a major incorporation of (15)N in N-DBPs. A significantly lower incorporation was observed for low-aromatic-content organic matter. (15)N-DCAcAm and (15)N-DCAN formations exhibited a linear correlation, suggesting a similar behavior of (15)N incorporation as SUVA increases. Chloramination of aromatic model

  3. Recent advances in trifluoromethylation of organic compounds using Umemoto's reagents.

    PubMed

    Zhang, Cai

    2014-09-14

    The incorporation of fluorine-containing moieties into organic compounds is of great importance in pharmaceutical, agricultural, and materials science. Within these organofluorides, the trifluoromethyl group is one of the most important motifs. In recent years, the trifluoromethyl group has attracted more and more attention, and many trifluoromethylated compounds have been found to possess special activities. However, until now, only a few methods have been developed to achieve this efficiently using Umemoto's reagents. This review highlights recent developments in the direct introduction of a trifluoromethyl group into organic compounds with Umemoto's reagents. Seven approaches to the trifluoromethylation of organic compounds are summarized: (i) trifluoromethylation of arenes, (ii) trifluoromethylation of alkenes, (iii) trifluoromethylation of terminal alkynes, (iv) deoxygenative trifluoromethylation of benzylic xanthates, (v) trifluoromethylation of ketoesters, (vi) trifluoromethylation of aryl boronic acids and aromatic amines (synthesis of ArCF3) and (vii) trifluoromethylation of biphenyl isocyanide derivatives.

  4. Inhibition of hydroxyl radical reaction with aromatics by dissolved natural organic matter

    SciTech Connect

    Lindsey, M.E.; Tarr, M.A.

    2000-02-01

    Remediation of hydrophobic pollutants is complicated by sorption of these compounds to hydrophobic sites of dissolved natural organic matter (NOM), suspended particulates, soil, and sediment. This sorption causes the pollutants to be less easily degraded by remediation techniques. Reaction of aromatic compounds with hydroxyl radical is inhibited by dissolved natural organic matter (NOM). The degree of inhibition is significantly greater than that expected based on a simple model in which aromatic compound molecules bound to NOM are considered to be unreactive. In this study, hydroxyl radical was produced at steady-state concentrations using Fenton chemistry (H{sub 2}O{sub 2} + Fe{sup 2+} {yields} Fe{sup 3+} + HO{sup {minus}} + HO{sm_bullet}). Suwannee River fulvic acid and humic acid were used as NOM. The most likely mechanism for the observed inhibition is that hydroxyl radical formation occurs in microenvironmental sites remote from the aromatic compounds. In addition to changes in kinetics, pyrene hydroxyl radical reaction also exhibited a mechanistic change in the presence of fulvic acid. The mechanism changed from a reaction that was apparently first-order in pyrene to one that was apparently second-order in pyrene, indicating that pyrene self-reaction may have become the dominant mechanism in the presence of fulvic acid. Dissolved NOM causes significant changes in the rate and mechanism of hydroxyl radical degradation of aromatic compounds. Consequently, literature rate constants measured in pure water will not be useful for predicting the degradation of pollutants in environmental systems. The kinetic and mechanistic information in this study will be useful for developing improved degradation methods involving Fenton chemistry.

  5. Molybdenum compounds in organic synthesis

    NASA Astrophysics Data System (ADS)

    Khusnutdinov, R. I.; Oshnyakova, T. M.; Dzhemilev, U. M.

    2017-02-01

    The review presents the first analysis and systematic discussion of data published in the last 35–40 years on the use of molybdenum compounds and complexes in organic synthesis and catalysis of various ion coordination and radical reactions. Detailed account is given of the key trends in the use of molybdenum complexes as catalysts of alkene epoxidation and oxyketonation, oxidation of sulfur, nitrogen and phosphorus compounds, hydrosilylation of 1,3-dienes, ketones and aldehydes, hydrostannylation of acetylenes and hydrogermylation of norbornadienes. Considerable attention is paid to the description of new reactions and in situ generation of highly reactive hypohalites, ROX and HOX, induced by molybdenum complexes and the use of hypohalites in oxidative transformations. Data on the application of molybdenum complexes in well-known reactions are discussed, including Kharasch and Pauson–Khand reactions, allylic alkylation of C-nucleophiles, aminocarbonylation of halo derivatives and oligomerization of cyclic dienes, trienes, alkynes and 1,3-dienes. The last Section of the review considers 'unusual' organic reactions involving molybdenum compounds and complexes. The bibliography includes 257 references.

  6. The potential production of aromatic compounds in flowers of Vanda tricolor

    NASA Astrophysics Data System (ADS)

    Darmasiwi, Sari; Indriani, Vitri; Innata, Dita; Semiarti, Endang

    2015-09-01

    Vanda tricolor is a famous natural orchid that has beautiful flowers with fragrance, therefore analysis of aromatic compounds of this orchid are important. The objective of this research was to isolate and identify the aromatic compounds of Vanda tricolor flower. The flower petals were picked at various developmental stages (0,4,7, and 10 days of flower opened) at 12.00 noon. It was then extracted using solvent extraction method and enfleurage method. The hexane:acetone (9:1) extract was considered as concrete extract, while some parts of concrete that were further extracted with ethanol, considered as absolute extract. The olive oil extract was considered as enfleurage extract. Those extracts were then evaporated using nitrogen gas, and analyzed by GC/MS (GC/MS-QP 2010S Shimadzu, Agilent HP-5 MS UI column, 30 m ID length: 0.25 mm, Helium gas carrier). The results showed that aromatic compounds composition in Vanda tricolor flower extracts were consisted of fatty acid derivates, monoterpenoids, sesquiterpenoids, benzenoids, phenylpropanoids, hydrocarbons and other oxygenated compounds. The highest diversity of aromatic compounds were found at the 10th days after floral opened, and the sensory test among those 3 (three) extracts showed that the absolute extract had more similarity with the original flower scent profile rather than the other extracts. This research showed that Vanda tricolor has potential production of aromatic compounds which was different compare to another species of Vanda.

  7. Volatile organic compound sensor system

    DOEpatents

    Schabron, John F.; Rovani, Jr., Joseph F.; Bomstad, Theresa M.; Sorini-Wong, Susan S.; Wong, Gregory K.

    2011-03-01

    Generally, this invention relates to the development of field monitoring methodology for new substances and sensing chemical warfare agents (CWAs) and terrorist substances. It also relates to a portable test kit which may be utilized to measure concentrations of halogenated volatile organic compounds (VOCs) in the field. Specifically it relates to systems for reliably field sensing the potential presence of such items while also distinguishing them from other elements potentially present. It also relates to overall systems and processes for sensing, reacting, and responding to an indicated presence of such substance, including modifications of existing halogenated sensors and arrayed sensing systems and methods.

  8. Volatile organic compound sensor system

    DOEpatents

    Schabron, John F.; Rovani, Jr., Joseph F.; Bomstad, Theresa M.; Sorini-Wong, Susan S.

    2009-02-10

    Generally, this invention relates to the development of field monitoring methodology for new substances and sensing chemical warfare agents (CWAs) and terrorist substances. It also relates to a portable test kit which may be utilized to measure concentrations of halogenated volatile organic compounds (VOCs) in the field. Specifically it relates to systems for reliably field sensing the potential presence of such items while also distinguishing them from other elements potentially present. It also relates to overall systems and processes for sensing, reacting, and responding to an indicated presence of such substance, including modifications of existing halogenated sensors and arrayed sensing systems and methods.

  9. SOLVENT-FREE REDUCTION OF AROMATIC NITRO COMPOUNDS WITH ALUMINA-SUPPORTED HYDRAZINE UNDER MICROWAVE IRRADIATION

    EPA Science Inventory

    In a solvent-free microwave-expedited process, aromatic nitro compounds are readily reduced to the corresponding amino compounds in good yield with hydrazine hydrate supported on alumina in presence of FeCl3, 6H2), Fe(III) oxide hydroxide or Fe(III) oxides.

  10. Delivery of complex organic compounds from evolved stars to the solar system.

    PubMed

    Kwok, Sun

    2011-12-01

    Stars in the late stages of evolution are able to synthesize complex organic compounds with aromatic and aliphatic structures over very short time scales. These compounds are ejected into the interstellar medium and distributed throughout the Galaxy. The structures of these compounds are similar to the insoluble organic matter found in meteorites. In this paper, we discuss to what extent stellar organics has enriched the primordial Solar System and possibly the early Earth.

  11. Metabolic engineering for microbial production of aromatic amino acids and derived compounds.

    PubMed

    Bongaerts, J; Krämer, M; Müller, U; Raeven, L; Wubbolts, M

    2001-10-01

    Metabolic engineering to design and construct microorganisms suitable for the production of aromatic amino acids and derivatives thereof requires control of a complicated network of metabolic reactions that partly act in parallel and frequently are in rapid equilibrium. Engineering the regulatory circuits, the uptake of carbon, the glycolytic pathway, the pentose phosphate pathway, and the common aromatic amino acid pathway as well as amino acid importers and exporters that have all been targeted to effect higher productivities of these compounds are discussed.

  12. New methods for the synthesis of aromatic fluorine compounds from industrial freons and polyfluorinated olefins

    SciTech Connect

    Nefedov, O.M.; Volchkov, N.V.

    1995-01-10

    The results from investigations into the development and application of a strategy and new methods for the synthesis of aromatic fluorine compounds, using fluorohalogenomethanes and polyfluorinated olefins as initial fluorine-containing substrates or structural units, are summarized. Two general methods for the production of fluoroarenes, involving the synthetic assembly of fluorobenzenoid structures through the cycloaddition of fluorocarbenes and fluoroalkenes to various 1,3-diene substrates and subsequent aromatization of the obtained fluorinated cyclopropane, cyclobutane, or cyclohexene adducts, are examined.

  13. Inversion and rotation processes involving non-planar aromatic compounds catalyzed by extended polycyclic aromatic hydrocarbons

    NASA Astrophysics Data System (ADS)

    Karton, Amir

    2014-10-01

    Using accurate quantum chemical calculations, we show that extended planar polycyclic aromatic hydrocarbons (PAHs) can efficiently catalyze a range of chemical processes involving non-planar aromatic systems. These include (i) bowl-to-bowl inversion of curved PAHs (e.g. corannulene and sumanene), (ii) 'flip-flop' inversion of helicenes (e.g. benzo[c]phenanthrene), and (iii) rotation about the Phsbnd Ph bond in biphenyls. Non-covalent π-π interactions between the planar catalyst and the substrate stabilize the planar transition structures to a greater extent than they stabilize the non-planar reactants. These result in surprisingly large catalytic enhancements (namely, the reaction barrier heights are reduced by 21-63% of the uncatalyzed reaction barriers).

  14. Biodegradation of Various Aromatic Compounds by Enriched Bacterial Cultures: Part A-Monocyclic and Polycyclic Aromatic Hydrocarbons.

    PubMed

    Oberoi, Akashdeep Singh; Philip, Ligy; Bhallamudi, S Murty

    2015-08-01

    Present study focused on the screening of bacterial consortium for biodegradation of monocyclic aromatic hydrocarbon (MAH) and polycyclic aromatic hydrocarbons (PAHs). Target compounds in the present study were naphthalene, acenaphthene, phenanthrene (PAHs), and benzene (MAH). Microbial consortia enriched with the above target compounds were used in screening experiments. Naphthalene-enriched consortium was found to be the most efficient consortium, based on its substrate degradation rate and its ability to degrade other aromatic pollutants with significantly high efficiency. Substrate degradation rate with naphthalene-enriched culture followed the order benzene > naphthalene > acenaphthene > phenanthrene. Chryseobacterium and Rhodobacter were discerned as the predominant species in naphthalene-enriched culture. They are closely associated to the type strain Chryseobacterium arthrosphaerae and Rhodobacter maris, respectively. Single substrate biodegradation studies with naphthalene (PAH) and benzene (MAH) were carried out using naphthalene-enriched microbial consortium (NAPH). Phenol and 2-hydroxybenzaldehyde were identified as the predominant intermediates during benzene and naphthalene degradation, respectively. Biodegradation of toluene, ethyl benzene, xylene, phenol, and indole by NAPH was also investigated. Monod inhibition model was able to simulate biodegradation kinetics for benzene, whereas multiple substrate biodegradation model was able to simulate biodegradation kinetics for naphthalene.

  15. Removal of aromatic hydrocarbon compounds by hydroxypropyl-cyclodextrin

    SciTech Connect

    1999-09-15

    Activated carbon has been used for the recovery and removal of benzene, toluene, and xylenes in air and water for a long time. However, removal of benzene, toluene, and xylenes from soil is very difficult. They can be removed by an increase in the apparent solubility of organic compounds in soil. The apparent solubilities of benzene, toluene, and xylene were investigated to estimate their inclusion behavior into natural cyclodextrins (CDs) and hydroxypropyl-cyclodextrins (HP-CDs) in the liquid phase. The apparent solubilities of benzene, toluene, and xylenes did not increase by adding natural CDs but did increase when HP-CDs were added. Benzene, toluene, and xylenes in a HP-CD solution depended on the relationship between the molecular diameter of benzene, toluene, and xylenes, the CD cavity size, and the 1-octanol-water partition coefficient. That of p-xylene was larger than that of o-xylene and m-xylene because of the smallest steric hindrance of p-xylene.

  16. Biodegradation of soluble aromatic compounds of jet fuel under anaerobic conditions: laboratory batch experiments.

    PubMed

    Zheng, Z; Breedveld, G; Aagaard, P

    2001-11-01

    Laboratory batch experiments were performed with contaminated aquifer sediments and four soluble aromatic components of jet fuel to assess their biodegradation under anaerobic conditions. The biodegradation of four aromatic compounds, toluene, o-xylene, 1,2,4-trimethylbenzene (TMB), and naphthalene, separately or together, was investigated under strictly anaerobic conditions in the dark for a period of 160 days. Of the aromatic compounds, toluene and o-xylene were degraded both as a single substrate and in a mixture with the other aromatic compounds, while TMB was not biodegraded as a single substrate, but was biodegraded in the presence of the other aromatic hydrocarbons. Substrate interaction is thus significant in the biodegradation of TMB. Biodegradation of naphthalene was not observed, either as a single substrate or in a mixture of other aromatic hydrocarbons. Although redox conditions were dominated by iron reduction, a clear relation between degradation and sulfate reduction was observed. Methanogenesis took place during the later stages of incubation. However, the large background of Fe(II) masked the increase of Fe(II) concentration due to iron reduction. Thus, although microbial reduction of Fe(III) is an important process, the evidence is not conclusive. Our results have shown that a better understanding of the degradation of complex mixtures of hydrocarbons under anaerobic conditions is important in the application of natural attenuation as a remedial method for soil and groundwater contamination.

  17. Environmental diagnostic analysis of ground water bacteria and their involvement in utilization of aromatic compounds

    SciTech Connect

    Wear, J.E. Jr.

    1993-05-01

    The objective of this study was to examine the hypothesis that select functional groups of bacteria from pristine sites have an innate ability to degrade synthetic aromatics that often contaminate groundwater environments,due to exposure to naturally occurring recalcitrant aromatics in their environment. This study demonstrates that subsurface microbial communities are capable of utilizing lignin and humic acid breakdown products. Utilizers of these compounds were found to be present in most all the wells tested. Even the deepest aquifer tested had utilizers present for all six of the aromatics tested. Highest counts for the aromatics tested were observed with the naturally occurring breakdown products of either lignin or humic acid. Carboxylic acids were found to be an important sole carbon source for groundwater bacteria possibly explained by the fact that they are produced by the oxidative cleavage of aromatic ring structures. The carbohydrate sole carbon sources that demonstrated the greatest densities were ones commonly associated with humics. This study indicates that utilization of naturally occurring aromatic compounds in the subsurface is an important nutritional source for groundwater bacteria. In addition, it suggests that adaptation to naturally occurring recalcitrant substrates is the origin of degradative pathways for xenobiotic compounds with analogous structure. This work has important implications for in situ bioremediation as a method of environmental cleanup.

  18. Capricious selectivity in electrophilic deuteration of methylenedioxy substituted aromatic compounds.

    PubMed

    Pohjoispää, Monika; Mera-Adasme, Raúl; Sundholm, Dage; Heikkinen, Sami; Hase, Tapio; Wähälä, Kristiina

    2014-11-07

    Ring deuteration via the SEAr mechanism, which is usually problem-free, is found to be troublesome with methylenedioxy substituent aromatics. We report a case where the deuteration not only partially fails at one of the ortho positions but also is completely prevented by a conformation dependent effect at the other o-position. Such selectivity discrepancies are important due to the widespread occurrence of methylenedioxy substituted natural products. Density functional theory calculations were used to elucidate the exchange reaction mechanism in 1,2-dialkoxybenzenes.

  19. Determining heats of detonation of non-aromatic energetic compounds without considering their heats of formation.

    PubMed

    Keshavarz, Mohammad Hossein

    2007-04-02

    A new procedure is introduced for calculating heats of detonation of non-aromatic energetic compounds through ratios of oxygen to carbon and hydrogen to oxygen as well as the contribution of some structural parameters. There is no need to use heats of formation of non-aromatic energetic compounds that are usually needed by the other methods. Moreover, this much simple method does not use any experimental and computed data of energetic materials. Predicted heats of detonation for 28 non-aromatic energetic compounds have a root mean square (rms) of deviation of 0.54 kJ/g from experiment, which show good agreement with respect to measured values. The new method is the simplest procedure for predicting heats of detonation and provides reliable results which are comparable with the other methods.

  20. Volatile organic compound sensing devices

    DOEpatents

    Lancaster, Gregory D.; Moore, Glenn A.; Stone, Mark L.; Reagen, William K.

    1995-01-01

    Apparatus employing vapochromic materials in the form of inorganic double complex salts which change color reversibly when exposed to volatile organic compound (VOC) vapors is adapted for VOC vapor detection, VOC aqueous matrix detection, and selective VOC vapor detection. The basic VOC vapochromic sensor is incorporated in various devices such as a ground probe sensor, a wristband sensor, a periodic sampling monitor, a soil/water penetrometer, an evaporative purge sensor, and various vacuum-based sensors which are particularly adapted for reversible/reusable detection, remote detection, continuous monitoring, or rapid screening of environmental remediation and waste management sites. The vapochromic sensor is used in combination with various fiber optic arrangements to provide a calibrated qualitative and/or quantitative indication of the presence of VOCs.

  1. Volatile organic compound sensing devices

    DOEpatents

    Lancaster, G.D.; Moore, G.A.; Stone, M.L.; Reagen, W.K.

    1995-08-29

    Apparatus employing vapochromic materials in the form of inorganic double complex salts which change color reversibly when exposed to volatile organic compound (VOC) vapors is adapted for VOC vapor detection, VOC aqueous matrix detection, and selective VOC vapor detection. The basic VOC vapochromic sensor is incorporated in various devices such as a ground probe sensor, a wristband sensor, a periodic sampling monitor, a soil/water penetrometer, an evaporative purge sensor, and various vacuum-based sensors which are particularly adapted for reversible/reusable detection, remote detection, continuous monitoring, or rapid screening of environmental remediation and waste management sites. The vapochromic sensor is used in combination with various fiber optic arrangements to provide a calibrated qualitative and/or quantitative indication of the presence of VOCs. 15 figs.

  2. A Green Starting Material for Electrophilic Aromatic Substitution for the Undergraduate Organic Laboratory

    ERIC Educational Resources Information Center

    Jones-Wilson, T. Michelle; Burtch, Elizabeth A.

    2005-01-01

    Electrophilic aromatic substitution (EAS) experiment is designed for the second-semester and undergraduate organic chemistry laboratory. In the EAS experiment, the principles of green chemistry are discussed and illustrated in conjunction with the presentation of electrophilic aromatic substitution.

  3. Organic compounds in concrete from demolition works.

    PubMed

    Van Praagh, M; Modin, H; Trygg, J

    2015-11-01

    This study aims to verify the effect of physically removing the outer surface of contaminated concrete on total contents and on potential mobility of pollutants by means of leaching tests. Reclaimed concrete from 3 industrial sites in Sweden were included: A tar impregnated military storage, a military tar track-depot, as well as concrete constructions used for disposing of pesticide production surplus and residues. Solid materials and leachates from batch and column leaching tests were analysed for metals, Cl, F, SO4, DOC and contents of suspected organic compounds (polycyclic aromatic hydrocarbons, PAH, and pesticides/substances for pesticide production such as phenoxy acids, chlorophenols and chlorocresols, respectively). In case of PAH contaminated concrete, results indicate that removing 1 or 5 mm of the surface lead to total concentrations below the Swedish guidelines for recycling of aggregates and soil in groundwork constructions. 3 out of 4 concrete samples contaminated with pesticides fulfilled Swedish guidelines for contaminated soil. Results from batch and column leaching tests indicated, however, that concentrations above environmental quality standards for certain PAH and phenoxy acids, respectively, might occur at site when the crushed concrete is recycled in groundwork constructions. As leaching tests engaged in the study deviated from leaching test standards with a limited number of samples, the potential impact of the leaching tests' equipment on measured PAH and pesticide leachate concentrations has to be evaluated in future work.

  4. Effects of organic matter composition on the partition behavior of polycyclic aromatic hydrocarbons (PAHs)

    SciTech Connect

    McGroddy, S.E.; Chiou, C.T.

    1995-12-31

    Sorption isotherms have been measured for a range of polycyclic aromatic hydrocarbons (PAHs) on soil samples, as well as contaminated and pristine sediment samples. The organic carbon normalized partition coefficients (K{sub oc}) measured with the sediment samples are higher than those measured for the soil samples. The observed difference is similar to that previously measured for highly nonpolar compounds such as carbon tetrachloride. The measured K{sub oc} values for the PAH compounds are comparable with the corresponding octanolwater partition coefficients (K{sub ow}). In contrast, the K{sub oc} values measured for carbon tetrachloride and other nonpolar solutes are approximately one tenth the K{sub ow} value for this compound. The highly aromatic nature of the PAH compounds appears to reduce their solubility in octanol; the resulting K{sub ow} values are comparable to the K{sub ow} values. Contaminated marine sediments show enhanced partition over pristine sediments although the enhancement factor is somewhat less than that seen with extremely nonpolar solutes (e.g. carbon tetrachloride). The partition behavior of PAHs appears to be sensitive to differences between the polarities of soil and sediment organic matters.

  5. Sorption of aromatic organic pollutants to grasses from water

    USGS Publications Warehouse

    Barbour, J.P.; Smith, J.A.; Chiou, C.T.

    2005-01-01

    The influence of plant lipids on the equilibrium sorption of three aromatic solutes from water was studied. The plant-water sorption isotherms of benzene, 1,2-dichlorobenzene, and phenanthrene were measured over a large range of solute concentrations using sealed vessels containing water, dried plant material, and solute. The plant materials studied include the shoots of annual rye, tall fescue, red fescue, and spinach as well as the roots of annual rye. Seven out of eight sorption isotherms were linear with no evidence of competitive effects between the solutes. For a given plant type, the sorption coefficient increased with decreasing solute water solubility. For a given solute, sorption increased with increasing plant lipid content. The estimated lipid-water partition coefficients of individual solutes were found to be significantly greater than the corresponding octanol-water partition coefficients. This indicates that plant lipids are a more effective partition solvent than octanol for the studied aromatic compounds. As expected, the solute lipid-water partition coefficients were log-linearly related to the respective water solubilities. For the compounds studied, partitioning into the lipids is believed to be the primary sorption mechanism. ?? 2005 American Chemical Society.

  6. Aromatic fluorine compounds. VIII. Plant growth regulators and intermediates

    USGS Publications Warehouse

    Finger, G.C.; Gortatowski, M.J.; Shiley, R.H.; White, R.H.

    1959-01-01

    The preparation and properties of 41 fluorophenoxyacetic acids, 4 fluorophenoxypropionic acids, 2 fluorobenzoic acids, several indole derivatives, and a number of miscellaneous compounds are described. Data are given for many intermediates such as new fluorinated phenols, anisoles, anilines and nitrobenzenes. Most of the subject compounds are related to a number of well-known herbicides or plant growth regulators such as 2,4-D, 2,4,5-T and others.

  7. Secondary organic aerosol from polycyclic aromatic hydrocarbons in Southeast Texas

    NASA Astrophysics Data System (ADS)

    Zhang, Hongliang; Ying, Qi

    2012-08-01

    Recent chamber studies show that low-volatility gas phase precursors such as polycyclic aromatic hydrocarbons (PAHs) can be a significant source of secondary organic aerosol (SOA). In this work, formation of SOA from the photo-oxidation products of PAHs is added to the SOA modeling framework of the Community Multiscale Air Quality (CMAQ) model to determine the regional distribution of SOA products from PAHs (PAH-SOA) and the contributions from sources in Southeast Texas during the Texas Air Quality Study 2006 (TexAQS 2006). Results show that PAHs released from anthropogenic sources can produce SOA mass as much as 10% of that from the traditional light aromatics or approximately 4% of total anthropogenic SOA. In areas under the influence of wildfire emissions, the amount of PAH-SOA can be as much as 50% of the SOA from light aromatics. A source-oriented modeling framework is adopted to determine the major sources of PAH-SOA by tracking the emitted PAHs and their oxidation products in the gas and aerosol phases from different sources separately. Among the eight sources (vehicles, solvent utilization, residential wood, industries, natural gas combustion, coal combustion, wildfire and other sources) that are tracked in the model, wildfire, vehicles, solvent and industries are the major sources of PAH-SOA. Coal and natural gas combustion appear to be less important in terms of their contributions to PAH-SOA.

  8. Azoarcus sp. CIB, an Anaerobic Biodegrader of Aromatic Compounds Shows an Endophytic Lifestyle

    PubMed Central

    Fernández, Helga; Prandoni, Nicolás; Fernández-Pascual, Mercedes; Fajardo, Susana; Morcillo, César; Díaz, Eduardo; Carmona, Manuel

    2014-01-01

    Background Endophytic bacteria that have plant growth promoting traits are of great interest in green biotechnology. The previous thought that the Azoarcus genus comprises bacteria that fit into one of two major eco-physiological groups, either free-living anaerobic biodegraders of aromatic compounds or obligate endophytes unable to degrade aromatics under anaerobic conditions, is revisited here. Methodology/Principal Findings Light, confocal and electron microscopy reveal that Azoarcus sp. CIB, a facultative anaerobe β-proteobacterium able to degrade aromatic hydrocarbons under anoxic conditions, is also able to colonize the intercellular spaces of the rice roots. In addition, the strain CIB displays plant growth promoting traits such nitrogen fixation, uptake of insoluble phosphorus and production of indoleacetic acid. Therefore, this work demonstrates by the first time that a free-living bacterium able to degrade aromatic compounds under aerobic and anoxic conditions can share also an endophytic lifestyle. The phylogenetic analyses based on the 16S rDNA and nifH genes confirmed that obligate endophytes of the Azoarcus genus and facultative endophytes, such as Azoarcus sp. CIB, locate into different evolutionary branches. Conclusions/Significance This is the first report of a bacterium, Azoarcus sp. CIB, able to degrade anaerobically a significant number of aromatic compounds, some of them of great environmental concern, and to colonize the rice as a facultative endophyte. Thus, Azoarcus sp. CIB becomes a suitable candidate for a more sustainable agricultural practice and phytoremediation technology. PMID:25340341

  9. Infrared Spectroscopy of Matrix-Isolated Polycyclic Aromatic Compounds and their Ions. 6; Polycyclic Aromatic Nitrogen Heterocycles

    NASA Technical Reports Server (NTRS)

    Mattioda, A. L.; Hudgins, Douglas M.; Bauschlicher, C. W., Jr.; Rosi, M.; Allamandola, L. J.; DeVincenzi, D. (Technical Monitor)

    2002-01-01

    The matrix-isolation technique has been employed to measure the mid-infrared spectra of several polycyclic aromatic nitrogen heterocycles in both neutral and cationic forms. The species studied include: 7,8 benzoquinoline (C13H9N); 2-azapyrene (C15H9N); 1- and 2-azabenz(a)anthracene (C17H11N); and 1-, 2-, and 4-azachrysene (also C17H11N). The experimentally measured band frequencies and intensities for each molecule are tabulated and compared with their theoretically calculated values computed using density functional theory at the B3LYP/4-31G level. The overall agreement between experiment and theory is quite good, in keeping with previous investigations involving the parent aromatic hydrocarbons. Several interesting spectroscopic trends are found to accompany nitrogen substitution into the aromatic framework of these compounds. First, for the neutral species, the nitrogen atom produces a significant increase in the total integrated infrared intensity across the 1600 - 1100/cm region and plays an essential role in the molecular vibration that underlies an uncharacteristically intense, discrete feature that is observed near 1400/cm in the spectra of 7,8 benzoquinoline, 1-azabenz(a)anthracene, and 4-azachrysene. The origin of this enhanced infrared activity and the nature of the new 1400/cm vibrational mode are explored. Finally, in contrast to the parent hydrocarbon species, these aromatic nitrogen heterocycles possess a significant permanent dipole moment. Consequently, these dipole moments and the rotational constants are reported for these species in their neutral and ionized forms.

  10. Comamonas testosteroni uses a chemoreceptor for tricarboxylic acid cycle intermediates to trigger chemotactic responses towards aromatic compounds.

    PubMed

    Ni, Bin; Huang, Zhou; Fan, Zheng; Jiang, Cheng-Ying; Liu, Shuang-Jiang

    2013-11-01

    Bacterial chemotaxis towards aromatic compounds has been frequently observed; however, knowledge of how bacteria sense aromatic compounds is limited. Comamonas testosteroni CNB-1 is able to grow on a range of aromatic compounds. This study investigated the chemotactic responses of CNB-1 to 10 aromatic compounds. We constructed a chemoreceptor-free, non-chemotactic mutant, CNB-1Δ20, by disruption of all 19 putative methyl-accepting chemotaxis proteins (MCPs) and the atypical chemoreceptor in strain CNB-1. Individual complementation revealed that a putative MCP (tagged MCP2201) was involved in triggering chemotaxis towards all 10 aromatic compounds. The recombinant sensory domain of MCP2201 did not bind to 3- or 4-hydroxybenzoate, protocatechuate, catechol, benzoate, vanillate and gentisate, but bound oxaloacetate, citrate, cis-aconitate, isocitrate, α-ketoglutarate, succinate, fumarate and malate. The mutant CNB-1ΔpmdF that lost the ability to metabolize 4-hydroxybenzoate and protocatechuate also lost its chemotactic response to these compounds, suggesting that taxis towards aromatic compounds is metabolism-dependent. Based on the ligand profile, we proposed that MCP2201 triggers taxis towards aromatic compounds by sensing TCA cycle intermediates. Our hypothesis was further supported by the finding that introduction of the previously characterized pseudomonad chemoreceptor (McpS) for TCA cycle intermediates into CNB-1Δ20 likewise triggered chemotaxis towards aromatic compounds.

  11. Composition and major sources of organic compounds in urban aerosols

    NASA Astrophysics Data System (ADS)

    Bi, Xinhui; Simoneit, Bernd R. T.; Sheng, Guoying; Ma, Shexia; Fu, Jiamo

    Total suspended particles (TSP), collected during June 2002 to July 2003 in Guangzhou, a typical economically developed city in South China, were analyzed for the organic compound compositions using gas chromatography-mass spectrometry (GC/MS). Over 140 organic compounds were detected in the aerosols and grouped into different classes including n-alkanes, hopanoids, polycyclic aromatic hydrocarbons, alkanols, fatty acids, dicarboxylic acids excluding oxalic acid, polyols/polyacids, lignin products, phytosterols, phthalates and water-soluble sugars. The total amounts of the identified organic compounds including unresolved complex mixture (UCM) ranged from 3112 ng/m 3 in spring to 5116 ng/m 3 in winter, comprising on seasonal average 2.8% of TSP. Primary organic compounds peaked in winter although there are no heating systems burning fuels in Guangzhou. The highest saccharide levels occurred in fall due to agricultural activities. This study demonstrated that utilization of fossil fuels, biomass burning, soil resuspension and plastic/refuse burning are the major contributors to the identified organic compounds in the urban atmosphere of South China.

  12. Effect of surfactants at low concentrations on the desorption and biodegradation of sorbed aromatic compounds in soil

    SciTech Connect

    Aronstein, B.N.; Calvillo, Y.M.; Alexander, M. )

    1991-10-01

    A study was conducted to determine the effect of low concentrations of surfactants on the biodegradation of sorbed aromatic compounds in soil. The nonionic alcohol ethoxylate surfactants Alfonic 810-60 and Novel II 1412-56 increased the extent of desorption of phenanthrene from a mineral soil. Alfonic 810-60 enhanced desorption of biphenyl from this soil at one concentration tested, but Novel II 1412-56 did not. Less than 0.01{per thousand} of the added phenanthrene and biphenyl was present in solution after their introduction into an organic soil, and the surfactants did not promote desorption. The two surfactants at 10 {mu}g/g of soil markedly increased the extent of biodegradation of phenanthrene in both the mineral and the organic soil; the stimulation was greater in the organic soil. Biphenyl mineralization in the mineral soil was not affected by either surfactant, but biodegradation in the organic soil was enhanced by Alfonic 810-60 at 100 {mu}g/g. The authors suggest that surfactants at low concentrations may promote the mineralization of sorbed aromatic compounds in polluted soils, even when surfactant-induced desorption is not appreciable.

  13. Occurrence and concentrations of selected trace elements, halogenated organic compounds, and polycyclic aromatic hydrocarbons in streambed sediments and results of water-toxicity testing in Westside Creeks and the San Antonio River, San Antonio, Texas, 2014

    USGS Publications Warehouse

    Crow, Cassi L.; Wilson, Jennifer T.; Kunz, James L.

    2016-12-01

    Sediment samples and samples for water-toxicity testing were collected during 2014 from several streams in San Antonio, Texas, known locally as the Westside Creeks (Alazán, Apache, Martínez, and San Pedro Creeks) and from the San Antonio River. Samples were collected during base flow and after periods of stormwater runoff (poststorm conditions) to determine baseline sediment- and water-quality conditions. Streambed-sediment samples were analyzed for selected constituents, including trace elements and organic contaminants such as pesticides, polychlorinated biphenyls (PCBs), brominated flame retardants, and polycyclic aromatic hydrocarbons (PAHs). Potential risks of contaminants in sediment were evaluated by comparing concentrations of contaminants in sediment to two effects-based sediment-quality guidelines: (1) a lower level, called the threshold effect concentration, below which, harmful effects to benthic biota are not expected, and (2) a higher level, the probable effect concentration (PEC), above which harmful effects are expected to occur frequently. Samples for water-toxicity testing were collected from each stream to provide information about fish toxicity in the study area. The trace metal lead was detected at potentially toxic concentrations greater than the PEC in both the base-flow and poststorm samples collected at two sites sampled on San Pedro Creek. The PECs for the pesticides dichlorodiphenyldichloroethane, dichlorodiphenyldichloroethylene, dichlorodiphenyltrichloroethane, and chlordane were exceeded in some of the samples at the same two sites on San Pedro Creek. Brominated flame retardants and polybrominated diphenyl ether (PBDE) 85, 153, and 154 were found in all streambed-sediment samples. Federal Environmental Quality Guidelines established by Environment Canada for PBDE 99 and PBDE 100 were exceeded in all samples in which PBDE 99 was detected and in a majority of the samples in which PBDE 100 was detected; the greatest concentrations

  14. Penicillium chrysogenum var. halophenolicum, a new halotolerant strain with potential in the remediation of aromatic compounds in high salt environments.

    PubMed

    Leitão, Ana Lúcia; García-Estrada, Carlos; Ullán, Ricardo Vicente; Guedes, Sumaya Ferreira; Martín-Jiménez, Patricia; Mendes, Benilde; Martín, Juan Francisco

    2012-01-20

    A halotolerant phenylacetate-degrading fungus Penicillium CLONA2, previously isolated from a salt mine at Algarve (Portugal), was identified as a variant of P. chrysogenum using the ITS-5,8S rDNA and the D1/D2 domain of 28S rDNA sequences. The metabolic features and genetic characteristics suggest that this strain belongs to a subgroup of P. chrysogenum, named var. halophenolicum. The presence of the penicillin biosynthetic cluster was proven by Southern hybridizations using probes internal to the pcbAB and penDE genes and sequencing of the pcbAB-pcbC intergenic region. However the pcbAB-pcbC divergent promoter region contained 20 point modifications with respect to that of the wild type P. chrysogenum NRRL1951. The CLONA2 strain produced non-aromatic natural penicillins rather than benzylpenicillin in a medium containing potassium phenylacetate (the precursor of benzylpenicillin) and was able to grow well on phenylacetatic acid using it as sole carbon source. Due to the ability of P. chrysogenum CLONA2 to degrade aromatic compounds, this strain may be an interesting organism for aromatic compounds remediation in high salinity environments.

  15. Sources of SOA gaseous precursors in contrasted urban environments: a focus on mono-aromatic compounds and intermediate volatility compounds

    NASA Astrophysics Data System (ADS)

    Salameh, Therese; Borbon, Agnès; Ait-Helal, Warda; Afif, Charbel; Sauvage, Stéphane; Locoge, Nadine; Bonneau, Stéphane; Sanchez, Olivier

    2016-04-01

    Among Volatile Organic Compounds (VOC), the mono-aromatic compounds so-called BTEX (Benzene, Toluene, Ethylbenzene, and Xylenes) and the intermediate volatility organic compounds (IVOC) with C>12 are two remarkable chemical families having high impact on health, as well as on the production of secondary pollutants like secondary organic aerosols (SOA) and ozone. However, the nature and relative importance of their sources and, consequently, their impact on SOA formation at urban scale is still under debate. On the one hand, BTEX observations in urban areas of northern mid-latitudes do not reconcile with emission inventories; the latter pointing to solvent use as the dominant source compared to traffic. Moreover, a recent study by Borbon et al. (2013) has shown an enrichment in the C7-C9 aromatic fraction in Paris atmosphere by a factor of 3 compared to other cities. Causes would be: (i) differences in gasoline composition, (ii) differences in vehicle fleet composition, and (iii) differences in solvent use related sources. On the other hand, many smog chamber studies have highlighted IVOCs as important SOA precursors over the last decade but their origin and importance in urban areas relative to other precursors like BTEX is still poorly addressed. Here we combined large VOC datasets to investigate sources of BTEX and IVOC in contrasted urban areas by source-receptor approaches and laboratory experiments. Ambient data include multi-site speciated ambient measurements of C2 to C17 VOCs (traffic, urban background, and tunnel) from air quality networks (ie. AIRPARIF in Paris) and intensive field campaigns (MEGAPOLI-Paris, TRANSEMED in Beirut and Istanbul, PHOTOPAQ in Brussels). Preliminary results for Paris suggest that traffic dominates BTEX concentrations while traffic and domestic heating for IVOC (>70%). In parallel, the detailed composition of the fuel liquid phase was determined at the laboratory for typical fuels distributed in Ile de France region (diesel, SP95

  16. Photoactivation and toxicity of mixtures of polycyclic aromatic hydrocarbon compounds in marine sediment

    SciTech Connect

    Swartz, R.C.; Ferraro, S.P.; Lamberson, J.O.; Cole, F.A.; Ozretich, R.J.; Boese, B.L.; Schults, D.W.; Behrenfeld, M.; Ankley, G.T.

    1997-10-01

    The direct toxicity and photoinduced toxicity of sediment-associated acenaphthene, phenanthrene, fluoranthene, and pyrene were determined for the marine amphipod Rhepoxynius abronius. The four polycyclic aromatic hydrocarbons (PAHs) were spiked into sediment in a concentration series of either single compounds or as approximately equitoxic mixtures of all four compounds. Standard 10-d sediment toxicity tests were conducted under fluorescent lighting. After 10 d, survivors were exposed for 1 h to ultraviolet (UV) radiation in the absence of sediment and then tested for their ability to bury in uncontaminated sediment. The 10-d median lethal concentrations (LC50s) were 2.31 mg acenaphthene/g organic carbon (OC), 2.22 mg phenanthrene/g OC, 3.31 mg fluoranthene/g OC, and 2.81 mg pyrene/g OC. These LC50s were used to calculate the sum of toxic units ({Sigma}TU) of the four PAHs in the approximately equitoxic mixtures. The {Sigma}TU LC50 was then calculated for the mixture treatments. If the toxicologic interaction of a mixture of contaminants is additive, {Sigma}TU LC50 = 1.0. The observed LC50 (1.55 {Sigma}TU) was slightly, but significantly, greater than unity, indicating that the interaction of PAHs in the mixture was less than additive. Exposure to UV radiation enhanced the toxic effects of fluoranthene and pyrene, but did not affect the toxicity of acenaphthene and phenanthrene. Effects of UV radiation on the toxicity of the mixture of four PAHs could be explained by the photoactivation of fluoranthene and pyrene alone. These results are consistent with predictions based on photophysical properties of PAH compounds.

  17. Trophic transfer of naturally produced brominated aromatic compounds in a Baltic Sea food chain.

    PubMed

    Dahlgren, Elin; Lindqvist, Dennis; Dahlgren, Henrik; Asplund, Lillemor; Lehtilä, Kari

    2016-02-01

    Brominated aromatic compounds (BACs) are widely distributed in the marine environment. Some of these compounds are highly toxic, such as certain hydroxylated polybrominated diphenyl ethers (OH-PBDEs). In addition to anthropogenic emissions through use of BACs as e.g. flame retardants, BACs are natural products formed by marine organisms such as algae, sponges, and cyanobacteria. Little is known of the transfer of BACs from natural producers and further up in the trophic food chain. In this study it was observed that total sum of methoxylated polybrominated diphenyl ethers (MeO-PBDEs) and OH-PBDEs increased in concentration from the filamentous red alga Ceramium tenuicorne, via Gammarus sp. and three-spined stickleback (Gasterosteus aculeatus) to perch (Perca fluviatilis). The MeO-PBDEs, which were expected to bioaccumulate, increased in concentration accordingly up to perch, where the levels suddenly dropped dramatically. The opposite pattern was observed for OH-PBDEs, where the concentration exhibited a general trend of decline up the food web, but increased in perch, indicating metabolic demethylation of MeO-PBDEs. Debromination was also indicated to occur when progressing through the food chain resulting in high levels of tetra-brominated MeO-PBDE and OH-PBDE congeners in fish, while some penta- and hexa-brominated congeners were observed to be the dominant products in the alga. As it has been shown that OH-PBDEs are potent disruptors of oxidative phosphorylation and that mixtures of different congener may act synergistically in terms of this toxic mode of action, the high levels of OH-PBDEs detected in perch in this study warrants further investigation into potential effects of these compounds on Baltic wildlife, and monitoring of their levels.

  18. Actions of a versatile fluorene-degrading bacterial isolate on polycyclic aromatic compounds.

    PubMed Central

    Grifoll, M; Selifonov, S A; Gatlin, C V; Chapman, P J

    1995-01-01

    Pseudomonas cepacia F297 grew with fluorene as a sole source of carbon and energy; its growth yield corresponded to an assimilation of about 40% of fluorene carbon. The accumulation of a ring meta-cleavage product during growth and the identification of 1-indanone in growth media and washed-cell suspensions suggest that strain F297 metabolizes fluorene by mechanisms analogous to those of naphthalene degradation. In addition to fluorene, strain F297 utilized for growth a wide variety of polycyclic aromatic compounds (PACs), including naphthalene, 2,3-dimethylnaphthalene, phenanthrene, anthracene, and dibenzothiophene. Fluorene-induced cells of the strain also transformed 2,6-dimethylnaphthalene, biphenyl, dibenzofuran, acenaphthene, and acenaphthylene. The identification of products formed from those substrates (by gas chromatography-mass spectrometry) in washed-cell suspensions indicates that P. cepacia F297 carries out the following reactions: (i) aromatic ring oxidation and cleavage, apparently using the pyruvate released for growth, (ii) methyl group oxidations, (iii) methylenic oxidations, and (iv) S oxidations of aromatic sulfur heterocycles. Strain F297 grew with a creosote-PAC mixture, producing an almost complete removal of all aromatic compounds containing 2 to 3 rings in 14 days, as demonstrated by gas chromatography analysis of the remaining PACs recovered from cultures. The identification of key chemicals confirmed that not only are certain compounds depleted but also the anticipated reaction products are found. PMID:7487007

  19. Aromatic compound emissions from municipal solid waste landfill: Emission factors and their impact on air pollution

    NASA Astrophysics Data System (ADS)

    Liu, Yanjun; Lu, Wenjing; Guo, Hanwen; Ming, Zhongyuan; Wang, Chi; Xu, Sai; Liu, Yanting; Wang, Hongtao

    2016-08-01

    Aromatic compounds (ACs) are major components of volatile organic compounds emitted from municipal solid waste (MSW) landfills. The ACs emissions from the working face of a landfill in Beijing were studied from 2014 to 2015 using a modified wind tunnel system. Emission factors (EFs) of fugitive ACs emissions from the working face of the landfill were proposed according to statistical analyses to cope with their uncertainty. And their impacts on air quality were assessed for the first time. Toluene was the dominant AC with an average emission rate of 38.8 ± 43.0 μg m-2 s-1 (at a sweeping velocity of 0.26 m s-1). An increasing trend in AC emission rates was observed from 12:00 to 18:00 and then peaked at 21:00 (314.3 μg m-2 s-1). The probability density functions (PDFs) of AC emission rates could be classified into three distributions: Gaussian, log-normal, and logistic. EFs of ACs from the working face of the landfill were proposed according to the 95th percentile cumulative emission rates and the wind effects on ACs emissions. The annual ozone formation and secondary organic aerosol formation potential caused by AC emissions from landfills in Beijing were estimated to be 8.86 × 105 kg year-1 and 3.46 × 104 kg year-1, respectively. Toluene, m + p-xylene, and 1,3,5-trimethylbenzene were the most significant contributors to air pollution. Although ACs pollutions from landfills accounts for less percentage (∼0.1%) compared with other anthropogenic sources, their fugitive emissions which cannot be controlled efficiently deserve more attention and further investigation.

  20. The synthesis of organic and inorganic compounds in evolved stars.

    PubMed

    Kwok, Sun

    2004-08-26

    Recent isotopic analysis of meteorites and interplanetary dust has identified solid-state materials of pre-solar origin. We can now trace the origin of these inorganic grains to the circumstellar envelopes of evolved stars. Moreover, organic (aromatic and aliphatic) compounds have been detected in proto-planetary nebulae and planetary nebulae, which are the descendants of carbon stars. This implies that molecular synthesis is actively happening in the circumstellar environment on timescales as short as several hundred years. The detection of stellar grains in the Solar System suggests that they can survive their journey through the interstellar medium and that they are a major contributor of interstellar grains.

  1. Chemical characterization and mutagenic properties of polycyclic aromatic compounds in sediment from tributaries of the Great Lakes

    USGS Publications Warehouse

    Fabacher, David L.; Schmitt, Christopher J.; Besser, John M.; Mac, Michael J.

    1988-01-01

    Sediments from four inshore industrial sites and a reference site in the Great Lakes were extracted with solvents and characterized chemically for polycyclic aromatic compounds (PACs). An aqueous phase and a crude organic extract were obtained. The crude organic extract was further resolved into fractions A-2 (polycyclic aromatic hydrocarbons) and A-3 (nitrogen-containing polycyclic aromatic compounds), which were analyzed for PACs by gas chromatography and gas chromatography-mass spectrometry. The extracts and fractions were tested for mutagenicity in three assays: Ames, rat hepatocyte unscheduled DNA synthesis, and Chinese hamster ovary hypoxanthine-guanine phosphoribosyl transferase (CHO/HGPRT). Sediments from the industrial sites contained 27 to 363 μg/g total PACs; the reference site, less than 1 μg/g. Qualitative differences in the residue profiles among the sites were attributable to the probable sources of the PACs (petroleum versus combustion). Only one industrial site yielded measurable (0.1 μg/g or more) concentrations of individual nitrogen-containing PACs. In the Ames assay, only the highest doses of the A-2 fractions from two sites approached positive results. Conversely, the crude organic extract and A-2 and A-3 fractions from all sites induced unscheduled DNA synthesis. Crude organic extracts and the A-2 and A-3 fractions from all industrial sites gave well-defined dose-response relations in the CHO/HGPRT assay. We established the presence of chemical mutagens in sediment that could be correlated with neoplasms in fish from many of the sites; however, the mutagenicity of the sediment extracts was not completely related to the degree of contamination by PACs. We also discuss the utility of mutagenicity assays in the evaluation of complex chemical mixtures and recommend the use of a CHO/HGPRT-type assay in which cells are not required to proliferate in the presence of potential interfering chemicals.

  2. Identification of volatile organic compounds in flowers of Astragalus lagopoides.

    PubMed

    Movafeghi, Ali; Delazar, Abbas; Amini, Majid; Asnaashari, Solmaz

    2012-01-01

    Composition of volatile organic compounds (VOCs) in flowers of Astragalus lagopoides was studied using a hydrodistillation extraction procedure coupled with gas chromatography-mass spectrometry. The analyses allowed the identification of a number of 25 compounds, among which the presence of several bioactive aromatic derivatives such as guaiacol, eugenol, linalool, α- and 4-terpineol as well as nerol was attention-grabbing. Moreover, some other compounds like cyclohexane, 2-bromoethyl with repellent function also appeared to be present in the flower. As a result, the floral VOCs profile of A. lagopoides might reflect an adaptation to attract specialised pollinator insects. These findings provide important information for advances in understanding the ecological and evolutionary perspectives of pollination biology of the giant genus Astragalus.

  3. Special applications of fluorinated organic compounds.

    PubMed

    Lewandowski, Grzegorz; Meissner, Egbert; Milchert, Eugeniusz

    2006-08-25

    The applications of fluorinated organic compounds (FOCs) as finishing agent for fabrics, components of extinguishing agents, electroplating bathes, lubricating oils, oxygen carriers in blood substitutes have been discussed. Recent achievements in methods of the fluorination and general principles of the synthesis of useful perfluorinated organic compounds are given as well.

  4. Aromatic interactions as control elements in stereoselective organic reactions.

    PubMed

    Krenske, Elizabeth H; Houk, K N

    2013-04-16

    This Account describes how attractive interactions of aromatic rings with other groups can influence and control the stereoselectivity of many reactions. Recent developments in theory have improved the accuracy in the modeling of aromatic interactions. Quantum mechanical modeling can now provide insights into the roles of these interactions at a level of detail not previously accessible, both for ground-state species and for transition states of chemical reactions. In this Account, we show how transition-state modeling led to the discovery of the influence of aryl groups on the stereoselectivities of several types of organic reactions, including asymmetric dihydroxylations, transfer hydrogenations, hetero-Diels-Alder reactions, acyl transfers, and Claisen rearrangements. Our recent studies have also led to a novel mechanistic picture for two classes of (4 + 3) cycloadditions, both of which involve reactions of furans with oxyallyl intermediates. The first class of cycloadditions, developed by Hsung, features neutral oxyallyl intermediates that contain a chiral oxazolidinone auxiliary. Originally, it was thought that these cycloadditions relied on differential steric crowding of the two faces of a planar intermediate. Computations reveal a different picture and show that cycloaddition with furan takes place preferentially through the more crowded transition state: the furan adds on the same side as the Ph substituent of the oxazolidinone. The crowded transition state is stabilized by a CH-π interaction between furan and Ph worth approximately 2 kcal/mol. Attractive interactions with aromatic rings also control the stereoselectivity in a second class of (4+3) cycloadditions involving chiral alkoxy siloxyallyl cations. Alkoxy groups derived from chiral α-methylbenzyl alcohols favor crowded transition states, where a stabilizing CH-π interaction is present between the furan and the Ar group. The cationic cycloadditions are stepwise, while the Hsung cycloadditions

  5. Aromatic Interactions as Control Elements in Stereoselective Organic Reactions

    PubMed Central

    2012-01-01

    Conspectus This Account describes how attractive interaction of aromatic rings with other groups can influence and control the stereoselectivity of many reactions. Recent developments in theory have led to improved accuracy in the modeling of aromatic interactions. Quantum mechanical modeling can now provide insights into the roles of these interactions at a level of detail not previously accessible, both for ground-state species and for transition states of chemical reactions. In this Account, we show how transition-state modeling led to the discovery of the influence of aryl groups on the stereoselectivities of several types of organic reactions. These reaction types include asymmetric dihydroxylations, transfer hydrogenations, hetero-Diels–Alder reactions, acyl transfers, and Claisen rearrangements. Our recent studies have led to a novel mechanistic picture for two classes of (4+3) cycloadditions, both of which involve reactions of furans with oxyallyl intermediates. The first class of cycloadditions, developed by Hsung, features neutral oxyallyls containing a chiral oxazolidinone auxiliary. Originally, these cycloadditions were thought rely on differential steric crowding of the two faces of a planar intermediate. Computations reveal a different picture and show that cycloadditions with furan takes place preferentially through the more crowded transition state, with furan adding on the same side as the oxazolidinone’s Ph substituent. The crowded transition state is stabilized by a CH–π interaction between furan and Ph, worth about 2.0 kcal/mol. Stereocontrol in a second class of (4+3) cycloadditions, involving chiral alkoxy siloxyallyl cations, also is controlled by attractive interactions with aromatic rings. Alkoxy groups derived from chiral α-methylbenzyl alcohols are found to favor crowded transition states, where a CH–π interaction is again present between furan and Ar. The cationic cycloadditions are stepwise, while the Hsung cycloadditions are

  6. Dechlorination of Aromatic Xenobiotic Compounds by Anaerobic Microorganisms

    DTIC Science & Technology

    1988-07-01

    presence of thiosulfate, the formation of formic acid , succinic acid and several other intermediates by Day 28 suggests that bicarbonate is used during...Methane Sulfonic Acid (HS-CoM)- Atmosphere ." Appi. Environ. Microbiol. 3U:781-791. 91. Smith, M.R., S.H. Zinder, and R.A. Mah. 1980. "Microbial...anaerobic by flooding, adding an anaerobic atmosphere and/or adding readily degradable organic matter. Some of the soils were rice paddy soils

  7. Aromatic compound glucosides, alkyl glucoside and glucide from the fruit of anise.

    PubMed

    Fujimatu, Eiko; Ishikawa, Toru; Kitajima, Junichi

    2003-07-01

    From the polar portion of the methanolic extract of the fruit of anise (Pimpinella anisum L.), which has been used as a spice and medicine since antiquity, four aromatic compound glucosides, an alkyl glucoside and a glucide were isolated together with 24 known compounds. The structures of the new compounds were clarified as (E)-3-hydroxyanethole beta-D-glucopyranoside, (E)-1'-(2-hydroxy-5-methoxyphenyl)propane beta-D-glucopyranoside, 3-hydroxyestragole beta-D-glucopyranoside, methyl syringate 4-O-beta-D-glucopyranoside, hexane-1,5-diol 1-O-beta-D-glucopyranoside and 1-deoxy-L-erythritol 3-O-beta-D-glucopyranoside by spectral investigation.

  8. Differential effects of topically applied formalin and aromatic compounds on neurogenic-mediated microvascular leakage in rat skin.

    PubMed

    Futamura, Masaki; Goto, Shiho; Kimura, Ryoko; Kimoto, Izumi; Miyake, Mio; Ito, Komei; Sakamoto, Tatsuo

    2009-01-08

    Various volatile organic compounds (VOCs) act as a causative agent of skin inflammation. We investigated the effect of topical application of several VOCs and formalin on microvascular leakage in rat skin. We tested capsaicin, which is a reagent that specifically causes the skin response via endogenously released tachykinins. Evans blue dye extravasation served as an index of the increase in skin vascular permeability. After shaving the abdomen, we applied formalin, m-xylene, toluene, styrene, benzene, ethylbenzene, acetone, diethyl ether, hexane, heptane, cyclohexane and capsaicin to the skin. At 40min after application, skin samples were collected. Among all of the VOCs tested, all of the aromatic compounds significantly produced skin microvascular leakage that was similar to formalin and capsaicin. We also investigated the skin responses seen after the intravenous administration of CP-99,994 (1.5 or 5mg/kg), which is a tachykinin NK1 receptor antagonist, ketotifen (1 or 3mg/kg), which is a histamine H1 receptor antagonist that stabilizes the mast cells, and the topical application of capsazepine (22.5 or 50mM), which is the transient receptor potential vanilloid 1 (TRPV1) antagonist. The response induced by formalin and capsaicin was completely inhibited by CP-99,994. On the other hand, the antagonist partially reduced the response induced by m-xylene, toluene and styrene by 39%, 50% and 46%, respectively. Capsazepine and ketotifen did not alter the response induced by formalin or any of the aromatic compounds. Like capsaicin, formalin and the aromatic compounds at least partially caused skin microvascular leakage, which was due to tachykinin NK1 receptor activation related to the release of tachykinins from the sensory nerve endings. However, it is unlikely that mast cells and TRPV1 play an important role in the skin response.

  9. Polycyclic aromatic compound profiles from extracts of Dreissenid mussels and gammarid amphipods coexisting in Hamilton Harbor

    SciTech Connect

    Marvin, C.H.; McCarry, B.E.; Allan, L.; Bryant, D.W.

    1995-06-01

    Aggregates of dreissenid mussels were collected in Hamilton Harbour (western Lake Ontario) from a south shore site (Randle Reef) in an area characterized by coal tar-contaminated sediments, and from a site on the north shore exposed to particulates circulating in the harbour water column. Samples were separated into three components: dreissend mussels, gammarid amphipods (Gammarus fasciatus), and particulate material. The samples were freeze-dried, and extracted using ultrasonication in dichloromethane. The organic solvent extracts were subjected to an open-column alumina and Sephadex LH-20 gel column clean-up procedure, and characterized by gas chromatography-mass spectrometry (GC-MS). The chromatographic profiles of all sample extracts were dominated by polycyclic aromatic hydrocarbons (PAH). The concentrations of the individual compounds were normalized for contaminant profile comparison of the extracts of dreissenids, amphipods, and particulates associated with aggregates of dreissenid mussels. These profiles were also compared with extracts of coal tar-contaminated sediment from the Randle Reef area, and extracts of suspended particulates obtained from sediment traps. The similarities in the PAH profiles provide evidence of exposure to a common source of contaminants. These data also show that PAH associated with suspended particulates obtained from sediment traps. The similarities in the PAH profiles provide evidence of exposure to a common source of contaminants. These data also show that PAH associated with suspended particulates in Hamilton Harbour are being accumulated by dreissenid mussels and gammarid amphipods.

  10. Degradation of Monochlorinated and Nonchlorinated Aromatic Compounds under Iron-Reducing Conditions

    PubMed Central

    Kazumi, J.; Haggblom, M. M.; Young, L. Y.

    1995-01-01

    The capacity for Fe(sup3+) to serve as an electron acceptor in the microbial degradation of monochlorinated and nonchlorinated aromatic compounds was investigated in anoxic sediment enrichments. The substrates tested included phenol, benzoate, aniline, their respective monochlorinated isomers, o-, m-, and p-cresol, and all six dimethylphenol isomers. Phenol and 2-, 3-, and 4-chlorophenol were utilized by anaerobic microorganisms, with the concomitant reduction of Fe(sup3+) to Fe(sup2+). The amount of Fe(sup2+) produced in the enrichments was 89 to 138% of that expected for the stoichiometric degradation of these substrates to CO(inf2), suggesting complete mineralization at the expense of Fe reduction. Under Fe-reducing conditions, there was initial loss of benzoate and 3-chlorobenzoate but not of 2- or 4-chlorobenzoate. In addition, there was initial microbial utilization of aniline but not of the chloroaniline isomers. There was also initial loss of o-, m-, and p-cresol in our enrichments. None of the dimethylphenol isomers, however, was degraded within 300 days. Furthermore, we tested the capacity of an Fe-reducing, benzoate-grown culture of Geobacter metallireducens GS-15 to utilize monochlorinated benzoates and phenols. G. metallireducens was able to degrade benzoate and phenol but none of their chlorinated isomers, suggesting that the degradation of chlorophenols in our sediment enrichments may be due to novel Fe-reducing organisms that have yet to be isolated. PMID:16535169

  11. Two-stage bile preparation with acetone for recovery of fluorescent aromatic compounds (FACs).

    PubMed

    Karami, Ali; Syed, Mohd A; Christianus, Annie; Willett, Kristine L; Mazzeo, Jeffrey R; Courtenay, Simon C

    2012-07-15

    In this study we sought to optimize recovery of fluorescent aromatic compounds (FACs) from the bile of African catfish (Clarias gariepinus) injected with 10mg/kg benzo[a]pyrene (BaP). Fractions of pooled bile were hydrolyzed, combined with ten volumes of methanol, ethanol, acetonitrile, or acetone, centrifuged and supernatants were analyzed by high-performance liquid chromatography with fluorescent detection (HPLC/FL). As well, to test whether FACs were being lost in solids from the centrifugation, pellets were resuspended, hydrolyzed and mixed with six volumes of the organic solvent that produced best FAC recovery from the supernatant, and subjected to HPLC/FL. Highest FAC concentrations were obtained with 2000μl and 1250μl acetone for supernatants and resuspended pellets respectively. FACs concentrations were negatively correlated with biliary protein content but were unaffected by addition of bovine serum albumin (BSA) followed by no incubation indicating that the presence of proteins in the biliary mixture does not simply interfere with detection of FACs. In another experiment, efficiency of acetone addition was compared to two different liquid-liquid extractions (L-LEs). Acetone additions provided significantly higher biliary FACs than the L-LE methods. The new two-stage bile preparation with acetone is an efficient, inexpensive and easily performed method.

  12. Antitumor and antiparasitic activity of novel ruthenium compounds with polycyclic aromatic ligands.

    PubMed

    Miserachs, Helena Guiset; Cipriani, Micaella; Grau, Jordi; Vilaseca, Marta; Lorenzo, Julia; Medeiros, Andrea; Comini, Marcelo A; Gambino, Dinorah; Otero, Lucía; Moreno, Virtudes

    2015-09-01

    Five novel ruthenium(II)-arene complexes with polycyclic aromatic ligands were synthesized, comprising three compounds of the formula [RuCl(η(6)-p-cym)(L)][PF6], where p-cym = 1-isopropyl-4-methylbenzene and L are the bidentate aromatic ligands 1,10-phenanthroline-5,6-dione, 1, 5-amine-1,10-phenanthroline, 4, or 5,6-epoxy-5,6-dihydro-phenanthroline, 5. In the other two complexes [RuCl2(η(6)-p-cym)(L')], the metal is coordinated to a monodentate ligand L', where L' is phenanthridine, 2, or 9-carbonylanthracene, 3. All compounds were fully characterized by mass spectrometry and elemental analysis, as well as NMR and IR spectroscopic techniques. Obtained ruthenium compounds as well as their respective ligands were tested for their antiparasitic and antitumoral activities. Even though all compounds showed lower Trypanosoma brucei activity than the free ligands, they also resulted less toxic on mammalian cells. Cytotoxicity assays on HL60 cells showed a moderate antitumoral activity for all ruthenium compounds. Compound 1 was the most potent antitumoral (IC50 = 1.26±0.78 μM) and antiparasitic (IC50 = 0.19 ± 0.05 μM) agent, showing high selectivity towards the parasites (selectivity index >100). As complex 1 was the most promising antitumoral compound, its interaction with ubiquitin as potential target was also studied. In addition, obtained ruthenium compounds were found to bind DNA, and they are thought to interact with this macromolecule mainly through intercalation of the aromatic ligand.

  13. Persistent organic pollutants and polycyclic aromatic hydrocarbons in mosses after fire at the Brazilian Antarctic Station.

    PubMed

    Colabuono, Fernanda Imperatrice; Taniguchi, Satie; Cipro, Caio Vinícius Zecchin; da Silva, Josilene; Bícego, Márcia Caruso; Montone, Rosalinda Carmela

    2015-04-15

    A fire at the Brazilian Antarctic Station on February 25th, 2012 led to the burning of material that produced organic pollutants. To evaluate the impact in the surrounding area, polycyclic aromatic hydrocarbons (PAHs) and persistent organic pollutants (POPs) were analyzed in moss samples collected in the vicinities of the station before and after the incident and compared to findings from previous studies in the same region. PCBs were on the same magnitude as that reported in previous studies, which could be associated to the global dispersion of these compounds and may not be related to the local fire. In contrast, concentrations of HCB and PAHs were higher than those reported in previous studies. No PBDEs were found above the method detection limit. Organic contaminant concentrations in mosses decreased a few months after the fire, which is an important characteristic when considering the use of mosses for monitoring recent exposure.

  14. Leaching of styrene and other aromatic compounds in drinking water from PS bottles.

    PubMed

    Ahmad, Maqbool; Bajahlan, Ahmad S

    2007-01-01

    Bottled water may not be safer, or healthier, than tap water. The present studies have proved that styrene and some other aromatic compounds leach continuously from polystyrene (PS) bottles used locally for packaging. Water sapmles in contact with PS were extracted by a preconcentration technique called as "purge and trap" and analysed by gas chromatograph-mass spectrometer (GC/MS). Eleven aromatic compounds were identified in these studies. Maximum concentration of styrene in PS bottles was 29.5 microg/L. Apart from styrene, ethyl benzene, toluene and benzene were also quantified but their concentrations were much less than WHO guide line values. All other compounds were in traces. Quality of plastic and storage time were the major factor in leaching of styrene. Concentration of styrene was increased to 69.53 microg/L after one-year storage. In Styrofoam and PS cups studies, hot water was found to be contaminated with styrene and other aromatic compounds. It was observed that temperature played a major role in the leaching of styrene monomer from Styrofoam cups. Paper cups were found to be safe for hot drinks.

  15. On the Extraction of Aromatic Compounds from Hydrocarbons by Imidazolium Ionic Liquids

    PubMed Central

    Cassol, Cláudia C.; Umpierre, Alexandre P.; Ebeling, Günter; Ferrera, Bauer; Chiaro, Sandra S. X.; Dupont, Jairton

    2007-01-01

    The liquid-liquid equilibrium for the ternary system formed by n-octane and aromatic (alkylbenzenes) and heteroaromatic compounds (nitrogen and sulfur containing heterocyles) and 1-alkyl-3-methylimidazolium ionic liquids (ILs) associated with various anions has been investigated. The selectivity on the extraction of a specific aromatic compound is influenced by anion volume, hydrogen bond strength between the anion and the imidazolium cation and the length of the 1-methyl-3-alkylimidazolium alkyl side chain. The interaction of alkylbenzenes and sulfur heterocyles with the IL is preferentially through CH-π hydrogen bonds and the quantity of these aromatics in the IL phase decreases with the increase of the steric hindrance imposed by the substituents on the aromatic nucleus. In the case of nitrogen heterocycles the interaction occurs preferentially through N(heteroaromatic)-H(imidazolium) hydrogen bonds and the extraction process is largely controlled by the nitrogen heterocycle pKa. Competitive extraction experiments suggest that benzene, pyridine and dibenzothiophene do not compete for the same hydrogen bond sites of the IL.

  16. Mass spectrometry investigation of Titan aerosols analogs formed with traces of aromatic compounds

    NASA Astrophysics Data System (ADS)

    Gautier, Thomas; Trainer, Melissa; Sebree, Joshua; Li, Xiang; Pinnick, Veronica; Getty, Stephanie; Brinckerhoff, Will

    2016-06-01

    The detection of benzene at ppm levels in Titan's atmosphere [1] by Cassini's Ion and Neutral Mass Spectrometer (INMS) supports the idea that aromatic and heteroaromatic reaction pathways may play an important role in Titan's aerosols formation. In laboratory studies it has been shown that these aromatic molecules are easily dissociated by ultraviolet radiation and can therefore contribute significantly to aerosol formation [2] and be used to dope the production of aerosol analogs [3]. In this work we investigate the effect on the aerosol composition and growth pattern of the chemical nature of the aromatic reactant used to produce aerosol. Analysis are performed using Laser Desorption-Time of Flight mass spectrometry (LD-TOF) and Fourier Transform Infrared Spectroscopy (FTIR) Infrared analysis of our samples shows that inclusion of aromatic compounds as trace precursors allows to better fit laboratory data to Titan aerosol spectra observed by Cassini [3,4]. The improvement is especially visible on the far infrared (˜200 cm-1) bands observed by CIRS [5]. LDMS results show that the aerosol growth patterns depend both on the number of rings and on the nitrogen content of the trace precursor used. We also perform MS/MS analysis on some prominent peaks of aerosol mass spectra. This MS/MS approach allows us to identify some of the key compounds in the aerosol growth processes.

  17. The studies on the aromaticity of fullerenes and their holmium endohedral compounds.

    PubMed

    Tan, Bisheng; Peng, Rufang; Li, Hongbo; Wang, Bing; Jin, Bo; Chu, Shijin; Long, Xinping

    2011-02-01

    Density functional theory BLYP/DNP was employed to optimize a series of fullerenes and their holmium endohedral compounds, including C(20), Ho@C(20), Ho(3+)@C(20), C(60), Ho@C(60), Ho(3+)@C(60),C(70), Ho@C(70), Ho(3+)@C(70) C(78), Ho@C(78), Ho(3+)@C(78), C(82),Ho@C(82) and Ho(3+)@C(82). DFT semi core pseudospot approximation was taken into consideration in the calculations of the element holmium because of its particular electronic structure. Fullerenes and their holmium endohedral compounds' aromaticity were studied in terms of structural criteria, energetic criteria, and reactivity criteria. The results indicate that the aromaticity of fullerenes was reduced when a holmium atom was introduced into the carbon cage, and the endohedral fullerenes' reactive activity enhance; but the aromaticity of the carbon cage increased when a Ho(3+) cation was encapsulated into a fullerene. Calculations of aromaticity and stability indicate that two paths can lead to the similar aim of preparing holmium endohedral fullerenes; that is, they can form from either a holmium atom or a holmium cation (Ho(3+)) reacting with fullerenes, respectively, and the latter is more favorable.

  18. Pseudomonads biodegradation of aromatic compounds in oil sands process-affected water.

    PubMed

    Zhang, Yanyan; McPhedran, Kerry N; Gamal El-Din, Mohamed

    2015-07-15

    Aromatic naphthenic acids (NAs) have been shown to be more toxic than the classical NAs found in oil sands process-affected water (OSPW). To reduce this toxicity, Pseudomonas fluorescens and Pseudomonas putida were used to determine their ability to biodegrade aromatic compounds including treatments considering the impacts of external carbon and iron addition. Results showed that with added carbon P. fluorescens and P. putida have the capability of biodegrading these aromatics. In the presence of external carbon, gene expression of a functional PAH-ring hydroxylating dioxygenase (PAH-RHDα) was determined through reverse transcription real-time PCR, suggesting active degradation of OSPW aromatic compounds. Although no significant classical NAs removal was observed during this process, toxicity was reduced by 49.3% under optimal conditions. OSPW toxicity was eliminated with the combination of ozonation at a dose of 80 mg/L followed by biodegradation, indicating that it is a promising combined OSPW treatment approach for the safe discharge to the aquatic environment.

  19. The Thermal Decomposition of Some Organic Lead Compounds

    DTIC Science & Technology

    1957-11-01

    5» Results 4 6. Discussion of Results 5 6.1 The Lead Salts of Aliphatic Aoids 5 6.2 The Lead Compounds of Aromatic Acids 7 6.3 Thermal...aliphatic carboxylic acids decompose to lead oxide in one stage which, in air, is largely oxidative in character. The compounds of the aromatic hydroxy... acids , however, first yield intermediate basio compounds of varying stability and these ultimately decompose to lead oxide at high temperatures

  20. Knitting aromatic polymers for efficient solid-phase microextraction of trace organic pollutants.

    PubMed

    Liu, Shuqin; Hu, Qingkun; Zheng, Juan; Xie, Lijun; Wei, Songbo; Jiang, Ruifen; Zhu, Fang; Liu, Yuan; Ouyang, Gangfeng

    2016-06-10

    A series of knitting aromatic polymers (KAPs) were successfully synthesized using a simple one-step Friedel-Crafts alkylation of aromatic monomers and were characterized by transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy, and X-ray photoelectron spectroscopy (XPS). Then, as-synthesized KAPs with large surface areas, unique pore structures and high thermal stability were prepared as solid-phase microextraction (SPME) coatings that exhibited good extraction abilities for a series of benzene compounds (i.e., benzene, toluene, ethylbenzene and m-xylene, which are referred to as BTEX) and polycyclic aromatic hydrocarbons (PAHs). Under the optimized conditions, the methodologies established for the determination of BTEX and PAHs using the KAPs-triPB and KAPs-B coatings, respectively, possessed wide linear ranges, low limits of detection (LODs, 0.10-1.13ngL(-1) for BTEX and 0.05-0.49ngL(-1) for PAHs) and good reproducibility. Finally, the proposed methods were successfully applied to the determination of BTEX and PAHs in environmental water samples, and satisfactory recoveries (93.6-124.2% for BTEX and 77.2-113.3% for PAHs) were achieved. This study provides a benchmark for exploiting novel microporous organic polymers (MOPs) for SPME applications.

  1. Obligate sulfide-dependent degradation of methoxylated aromatic compounds and formation of methanethiol and dimethyl sulfide by a freshwater sediment isolate, Parasporobacterium paucivorans gen. nov., sp. nov.

    PubMed

    Lomans, B P; Leijdekkers, P; Wesselink, J J; Bakkes, P; Pol, A; van der Drift, C; den Camp, H J

    2001-09-01

    Methanethiol (MT) and dimethyl sulfide (DMS) have been shown to be the dominant volatile organic sulfur compounds in freshwater sediments. Previous research demonstrated that in these habitats MT and DMS are derived mainly from the methylation of sulfide. In order to identify the microorganisms that are responsible for this type of MT and DMS formation, several sulfide-rich freshwater sediments were amended with two potential methyl group-donating compounds, syringate and 3,4,5-trimethoxybenzoate (0.5 mM). The addition of these methoxylated aromatic compounds resulted in excess accumulation of MT and DMS in all sediment slurries even though methanogenic consumption of MT and DMS occurred. From one of the sediment slurries tested, a novel anaerobic bacterium was isolated with syringate as the sole carbon source. The strain, designated Parasporobacterium paucivorans, produced MT and DMS from the methoxy groups of syringate. The hydroxylated aromatic residue (gallate) was converted to acetate and butyrate. Like Sporobacterium olearium, another methoxylated aromatic compound-degrading bacterium, the isolate is a member of the XIVa cluster of the low-GC-content Clostridiales group. However, the new isolate differs from all other known methoxylated aromatic compound-degrading bacteria because it was able to degrade syringate in significant amounts only in the presence of sulfide.

  2. Solubilization and biodegradation of polycyclic aromatic hydrocarbon compounds in soil-water suspensions with surfactants

    SciTech Connect

    Laha, S.

    1992-01-01

    Hydrophobic organic compounds (HOCs) sorb strongly onto soil and sediment material, and the effectiveness of microbial treatment can be diminished by HOC phase partitioning and decreased substrate accessibility to microorganisms. Surfactant addition has been suggested as a technique for decreasing the interfacial tension and partitioning of the HOC with soil, and thereby increasing HOC mobility and bioavailability. However, this study indicates that nonionic surfactant solubilization of HOCs from soil may not be beneficial for the enhancement of soil bioremediation. The solubilization and microbial degradation of phenanthrene, a three-ring polycyclic aromatic hydrocarbon (PAH) compound, was examined in various soil-water systems with commercially-available surface-active agents. This was accomplished by a series of batch tests using radiolabeled techniques. The purpose of surfactant addition was to assess the effect of surfactant solubilization of PAHs on their biodegradation. For soil-water suspensions without surfactant approximately 50-60% of the phenanthrene was mineralized over the course of ten weeks. The addition of nonionic surface-active agents was observed not to be beneficial for microbial mineralization of phenanthrene in the soil-water systems, and for supra-CMC surfactant doses phenanthrene mineralization was completely inhibited for all the surfactants tested. Sub-CMC levels of surfactant in the soil-water systems generally did not have an inhibitory effect on phenanthrene mineralization, but neither did such doses serve to enhance the rate of degradation, which proceeded most rapidly in the absence of any surfactant. Companion tests suggest that the supra-CMC inhibitory effect is not a toxicity phenomenon, per se, of the surfactant or micellized PAH. An assessment of the results from the various experiments suggest that the inhibitory effect is probably related to a reversible physiological surfactant micelle-bacteria interaction.

  3. Structural and replicative diversity of large plasmids from sphingomonads that degrade polycyclic aromatic compounds and xenobiotics.

    PubMed

    Basta, Tamara; Buerger, Sibylle; Stolz, Andreas

    2005-06-01

    The plasmids from 16 sphingomonads which degrade various xenobiotics and polycyclic aromatic compounds were compared with the previously sequenced plasmid pNL1 from Sphingomonas aromaticivorans F199. The replicase genes repAaAb from plasmid pNL1 were amplified by PCR and used as a gene probe for the identification of plasmids belonging to the same incompatibility group as plasmid pNL1. Plasmids were prepared from various sphingomonads and hybridized with the repA gene probe. Positive hybridization signals were obtained with plasmids of approximately 160-195 kb from Sphingomonas subterranea and S. aromaticivorans B0695, which had been isolated from the same subsurface location as S. aromaticivorans F199. The repA probe also hybridized with plasmids from Sphingomonas xenophaga BN6, Sphingomonas sp. HH69 and Sphingomonas macrogoltabidus, which had been isolated from different continents and which utilize different organic compounds than S. aromaticivorans F199 and the other subsurface strains. The results of the hybridization experiments were confirmed by PCR experiments using primers deduced from the repAaAb region of plasmid pNL1. Nucleotide sequence comparisons suggested that three gene clusters were conserved between plasmid pNL1 and plasmid pBN6 from the naphthalenesulfonate- degrading strain S. xenophaga BN6. From these sequence comparisons, PCR primers were derived in order to detect the respective gene clusters in the other strains and to deduce their position relative to each other. These experiments demonstrated that all analysed subsurface strains harboured the same three gene clusters, but that the position and distance from each other of the clusters varied considerably among the different strains.

  4. Methods of making organic compounds by metathesis

    DOEpatents

    Abraham, Timothy W.; Kaido, Hiroki; Lee, Choon Woo; Pederson, Richard L.; Schrodi, Yann; Tupy, Michael John

    2015-09-01

    Described are methods of making organic compounds by metathesis chemistry. The methods of the invention are particularly useful for making industrially-important organic compounds beginning with starting compositions derived from renewable feedstocks, such as natural oils. The methods make use of a cross-metathesis step with an olefin compound to produce functionalized alkene intermediates having a pre-determined double bond position. Once isolated, the functionalized alkene intermediate can be self-metathesized or cross-metathesized (e.g., with a second functionalized alkene) to produce the desired organic compound or a precursor thereto. The method may be used to make bifunctional organic compounds, such as diacids, diesters, dicarboxylate salts, acid/esters, acid/amines, acid/alcohols, acid/aldehydes, acid/ketones, acid/halides, acid/nitriles, ester/amines, ester/alcohols, ester/aldehydes, ester/ketones, ester/halides, ester/nitriles, and the like.

  5. Organic Compounds in Circumstellar and Interstellar Environments

    NASA Astrophysics Data System (ADS)

    Kwok, Sun

    2015-06-01

    Recent research has discovered that complex organic matter is prevalent throughout the Universe. In the Solar System, it is found in meteorites, comets, interplanetary dust particles, and planetary satellites. Spectroscopic signatures of organics with aromatic/aliphatic structures are also found in stellar ejecta, diffuse interstellar medium, and external galaxies. From space infrared spectroscopic observations, we have found that complex organics can be synthesized in the late stages of stellar evolution. Shortly after the nuclear synthesis of the element carbon, organic gas-phase molecules are formed in the stellar winds, which later condense into solid organic particles. This organic synthesis occurs over very short time scales of about a thousand years. In order to determine the chemical structures of these stellar organics, comparisons are made with particles produced in the laboratory. Using the technique of chemical vapor deposition, artificial organic particles have been created by injecting energy into gas-phase hydrocarbon molecules. These comparisons led us to believe that the stellar organics are best described as amorphous carbonaceous nanoparticles with mixed aromatic and aliphatic components. The chemical structures of the stellar organics show strong similarity to the insoluble organic matter found in meteorites. Isotopic analysis of meteorites and interplanetary dust collected in the upper atmospheres have revealed the presence of pre-solar grains similar to those formed in old stars. This provides a direct link between star dust and the Solar System and raises the possibility that the early Solar System was chemically enriched by stellar ejecta with the potential of influencing the origin of life on Earth.

  6. Organic compounds in circumstellar and interstellar environments.

    PubMed

    Kwok, Sun

    2015-06-01

    Recent research has discovered that complex organic matter is prevalent throughout the Universe. In the Solar System, it is found in meteorites, comets, interplanetary dust particles, and planetary satellites. Spectroscopic signatures of organics with aromatic/aliphatic structures are also found in stellar ejecta, diffuse interstellar medium, and external galaxies. From space infrared spectroscopic observations, we have found that complex organics can be synthesized in the late stages of stellar evolution. Shortly after the nuclear synthesis of the element carbon, organic gas-phase molecules are formed in the stellar winds, which later condense into solid organic particles. This organic synthesis occurs over very short time scales of about a thousand years. In order to determine the chemical structures of these stellar organics, comparisons are made with particles produced in the laboratory. Using the technique of chemical vapor deposition, artificial organic particles have been created by injecting energy into gas-phase hydrocarbon molecules. These comparisons led us to believe that the stellar organics are best described as amorphous carbonaceous nanoparticles with mixed aromatic and aliphatic components. The chemical structures of the stellar organics show strong similarity to the insoluble organic matter found in meteorites. Isotopic analysis of meteorites and interplanetary dust collected in the upper atmospheres have revealed the presence of pre-solar grains similar to those formed in old stars. This provides a direct link between star dust and the Solar System and raises the possibility that the early Solar System was chemically enriched by stellar ejecta with the potential of influencing the origin of life on Earth.

  7. University and Secondary School Students' Misconceptions about the Concept of "Aromaticity" in Organic Chemistry

    ERIC Educational Resources Information Center

    Topal, Giray; Oral, Behcet; Ozden. Mustafa

    2007-01-01

    Aromaticity concept is given incorrect or incomplete to the student in secondary education and knowledge based on this basic concept has been caused to another misconception in future. How are the achievement levels relating to the comprehension of various characteristics of aromatic compounds for the first and third grade students attending…

  8. Quick estimation of heats of detonation of aromatic energetic compounds from structural parameters.

    PubMed

    Keshavarz, Mohammad Hossein

    2007-05-08

    In this paper, a simple procedure is introduced for a quick and reliable estimation of detonation heats of aromatic energetic compounds without considering heats of formation of energetic compounds. This method does not use any experimental or computed data of energetic materials. The methodology assumes that the heat of detonation of an energetic compound with composition of C(a)H(b)N(c)O(d) can be obtained from the number of nitrogens, ratios of oxygen to carbon and hydrogen to oxygen as well as the contribution of some specific functional groups. There is no need to use any assumed decomposition products to calculate heats of detonation for energetic compounds. Predicted heats of detonation of pure energetic compounds with the product H(2)O in the liquid state for 31 aromatic energetic compounds have a root mean square (rms) of deviation of 0.32 kJ/g from experiment. The new method gives good results with respect to two empirical methods which use measured heats of formation of explosives with two sets of decomposition gases.

  9. The sensitive and selective adsorption of aromatic compounds with highly crosslinked polymer nanoparticles

    NASA Astrophysics Data System (ADS)

    Liu, Shuqin; Chen, Darui; Zheng, Juan; Zeng, Lewei; Jiang, Jijun; Jiang, Ruifeng; Zhu, Fang; Shen, Yong; Wu, Dingcai; Ouyang, Gangfeng

    2015-10-01

    This study presents the preparation and characterization of a nanoscale Davankov-type hyper-crosslinked-polymer (HCP) as an adsorbent of benzene-ring-containing dyes and organic pollutants. HCP nanoparticles post-crosslinked from a poly(DVB-co-VBC) precursor were synthesized in this study, possessing ultrahigh surface area, hydrophobicity and stability. The as-synthesized Davankov-type HCP exhibited a rapid and selective adsorption ability towards the benzene-ring-containing dyes due to its highly conjugated structure. Besides, for the first time, the prepared HCP nanoparticles were adopted for the adsorption of nonpolar organic pollutants by means of solid-phase microextraction (SPME). Owing to its high hydrophobicity, diverse pore size distribution and highly conjugated structure, a 10 μm HCP coating exhibited excellent adsorption abilities towards benzene-ring-containing polycyclic aromatic hydrocarbons (PAHs) and benzene series compounds (benzene, toluene, ethylbenzene and o-xylene; abbreviated to BTEX) and to highly hydrophobic long-chain n-alkanes. Finally, the HCP-nanoparticles-coated SPME fiber was applied to the simultaneous analysis of five PAHs in environmental water samples and satisfactory recoveries were achieved. The findings could provide a new benchmark for the exploitation of superb HCPs as effective adsorbents for SPME or other adsorption applications.This study presents the preparation and characterization of a nanoscale Davankov-type hyper-crosslinked-polymer (HCP) as an adsorbent of benzene-ring-containing dyes and organic pollutants. HCP nanoparticles post-crosslinked from a poly(DVB-co-VBC) precursor were synthesized in this study, possessing ultrahigh surface area, hydrophobicity and stability. The as-synthesized Davankov-type HCP exhibited a rapid and selective adsorption ability towards the benzene-ring-containing dyes due to its highly conjugated structure. Besides, for the first time, the prepared HCP nanoparticles were adopted for the

  10. Biodegradation of Various Aromatic Compounds by Enriched Bacterial Cultures: Part B--Nitrogen-, Sulfur-, and Oxygen-Containing Heterocyclic Aromatic Compounds.

    PubMed

    Oberoi, Akashdeep Singh; Philip, Ligy; Bhallamudi, S Murty

    2015-07-01

    Present study focused on the biodegradation of various heterocyclic nitrogen, sulfur, and oxygen (NSO) compounds using naphthalene-enriched culture. Target compounds in the study were pyridine, quinoline, benzothiophene, and benzofuran. Screening studies were carried out using different microbial consortia enriched with specific polycyclic aromatic hydrocarbon (PAH) and NSO compounds. Among different microbial consortia, naphthalene-enriched culture was the most efficient consortium based on high substrate degradation rate. Substrate degradation rate with naphthalene-enriched culture followed the order pyridine > quinoline > benzofuran > benzothiophene. Benzothiophene and benzofuran were found to be highly recalcitrant pollutants. Benzothiophene could not be biodegraded when concentration was above 50 mg/l. It was observed that 2-(1H)-quinolinone, benzothiophene-2-one, and benzofuran-2,3-dione were formed as metabolic intermediates during biodegradation of quinoline, benzothiophene, and benzofuran, respectively. Quinoline-N and pyridine-N were transformed into free ammonium ions during the biodegradation process. Biodegradation pathways for various NSO compounds are proposed. Monod inhibition model was able to simulate single substrate biodegradation kinetics satisfactorily. Benzothiophene and benzofuran biodegradation kinetics, in presence of acetone, was simulated using a generalized multi-substrate model.

  11. New graphene fiber coating for volatile organic compounds analysis.

    PubMed

    Zhang, GuoJuan; Guo, XiaoXi; Wang, ShuLing; Wang, XueLan; Zhou, YanPing; Xu, Hui

    2014-10-15

    In the work, a novel graphene-based solid phase microextraction-gas chromatography/mass spectrometry method was developed for the analysis of trace amount of volatile organic compounds in human exhaled breath vapor. The graphene fiber coating was prepared by a one-step hydrothermal reduction reaction. The fiber with porous and wrinkled structure exhibited excellent extraction efficiency toward eight studied volatile organic compounds (two n-alkanes, five n-aldehydes and one aromatic compound). Meanwhile, remarkable thermal and mechanical stability, long lifespan and low cost were also obtained for the fiber. Under the optimal conditions, the developed method provided low limits of detection (1.0-4.5ngL(-1)), satisfactory reproducibility (3.8-13.8%) and acceptable recoveries (93-122%). The method was applied successfully to the analysis of breath samples of lung cancer patients and healthy individuals. The unique advantage of this approach includes simple setup, non-invasive analysis, cost-efficient and sufficient sensitivity. The proposed method supply us a new possibility to monitor volatile organic compounds in human exhaled breath samples.

  12. Organic electronic devices using phthalimide compounds

    DOEpatents

    Hassan, Azad M.; Thompson, Mark E.

    2012-10-23

    Organic electronic devices comprising a phthalimide compound. The phthalimide compounds disclosed herein are electron transporters with large HOMO-LUMO gaps, high triplet energies, large reduction potentials, and/or thermal and chemical stability. As such, these phthalimide compounds are suitable for use in any of various organic electronic devices, such as OLEDs and solar cells. In an OLED, the phthalimide compounds may serve various functions, such as a host in the emissive layer, as a hole blocking material, or as an electron transport material. In a solar cell, the phthalimide compounds may serve various functions, such as an exciton blocking material. Various examples of phthalimide compounds which may be suitable for use in the present invention are disclosed.

  13. Organic electronic devices using phthalimide compounds

    DOEpatents

    Hassan, Azad M.; Thompson, Mark E.

    2013-03-19

    Organic electronic devices comprising a phthalimide compound. The phthalimide compounds disclosed herein are electron transporters with large HOMO-LUMO gaps, high triplet energies, large reduction potentials, and/or thermal and chemical stability. As such, these phthalimide compounds are suitable for use in any of various organic electronic devices, such as OLEDs and solar cells. In an OLED, the phthalimide compounds may serve various functions, such as a host in the emissive layer, as a hole blocking material, or as an electron transport material. In a solar cell, the phthalimide compounds may serve various functions, such as an exciton blocking material. Various examples of phthalimide compounds which may be suitable for use in the present invention are disclosed.

  14. Organic electronic devices using phthalimide compounds

    DOEpatents

    Hassan, Azad M.; Thompson, Mark E.

    2010-09-07

    Organic electronic devices comprising a phthalimide compound. The phthalimide compounds disclosed herein are electron transporters with large HOMO-LUMO gaps, high triplet energies, large reduction potentials, and/or thermal and chemical stability. As such, these phthalimide compounds are suitable for use in any of various organic electronic devices, such as OLEDs and solar cells. In an OLED, the phthalimide compounds may serve various functions, such as a host in the emissive layer, as a hole blocking material, or as an electron transport material. In a solar cell, the phthalimide compounds may serve various functions, such as an exciton blocking material. Various examples of phthalimide compounds which may be suitable for use in the present invention are disclosed.

  15. Structural and functional characterization of solute binding proteins for aromatic compounds derived from lignin: p-coumaric acid and related aromatic acids.

    PubMed

    Tan, Kemin; Chang, Changsoo; Cuff, Marianne; Osipiuk, Jerzy; Landorf, Elizabeth; Mack, Jamey C; Zerbs, Sarah; Joachimiak, Andrzej; Collart, Frank R

    2013-10-01

    Lignin comprises 15-25% of plant biomass and represents a major environmental carbon source for utilization by soil microorganisms. Access to this energy resource requires the action of fungal and bacterial enzymes to break down the lignin polymer into a complex assortment of aromatic compounds that can be transported into the cells. To improve our understanding of the utilization of lignin by microorganisms, we characterized the molecular properties of solute binding proteins of ATP-binding cassette transporter proteins that interact with these compounds. A combination of functional screens and structural studies characterized the binding specificity of the solute binding proteins for aromatic compounds derived from lignin such as p-coumarate, 3-phenylpropionic acid and compounds with more complex ring substitutions. A ligand screen based on thermal stabilization identified several binding protein clusters that exhibit preferences based on the size or number of aromatic ring substituents. Multiple X-ray crystal structures of protein-ligand complexes for these clusters identified the molecular basis of the binding specificity for the lignin-derived aromatic compounds. The screens and structural data provide new functional assignments for these solute-binding proteins which can be used to infer their transport specificity. This knowledge of the functional roles and molecular binding specificity of these proteins will support the identification of the specific enzymes and regulatory proteins of peripheral pathways that funnel these compounds to central metabolic pathways and will improve the predictive power of sequence-based functional annotation methods for this family of proteins.

  16. Theoretical and experimental study of polycyclic aromatic compounds as β-tubulin inhibitors.

    PubMed

    Olazarán, Fabian E; García-Pérez, Carlos A; Bandyopadhyay, Debasish; Balderas-Rentería, Isaias; Reyes-Figueroa, Angel D; Henschke, Lars; Rivera, Gildardo

    2017-03-01

    In this work, through a docking analysis of compounds from the ZINC chemical library on human β-tubulin using high performance computer cluster, we report new polycyclic aromatic compounds that bind with high energy on the colchicine binding site of β-tubulin, suggesting three new key amino acids. However, molecular dynamic analysis showed low stability in the interaction between ligand and receptor. Results were confirmed experimentally in in vitro and in vivo models that suggest that molecular dynamics simulation is the best option to find new potential β-tubulin inhibitors. Graphical abstract Bennett's acceptance ratio (BAR) method.

  17. A New Aromatic Compound from the Stem Bark of Terminalia catappa.

    PubMed

    Pertuit, David; Mitaine-Offer, Anne-Claire; Miyamoto, Tomofumi; Tanaka, Chiaki; Delemasure, Stéphanie; Dutartre, Patrick; Lacaille-Dubois, Marie-Aleth

    2015-06-01

    A new aromatic compound 3,4,5-trimethoxyphenyl-1-O-(4-sulfo)-β-D-glucopyranoside (1), in addition to two triterpenoid saponins (chebuloside II, arjunoglucoside II), two triterpenes (arjunolic acid and 3-betulinic acid) and sitosterol-3-O-β-D-glucopyranoside have been isolated from the barks of Terminalia catappa. Their structures have been established on the basis of spectroscopic techniques (1D/2D NMR) and MS. Their cytotoxicity and antiinflammatory activity, together with the antioxidant capacity of compound 1 were also evaluated.

  18. Microwave spectra of some volatile organic compounds

    NASA Technical Reports Server (NTRS)

    White, W. F.

    1975-01-01

    A computer-controlled microwave (MRR) spectrometer was used to catalog reference spectra for chemical analysis. Tables of absorption frequency, peak absorption intensity, and integrated intensity are included for 26 volatile organic compounds, all but one of which contain oxygen.

  19. VOLATILE ORGANIC COMPOUNDS AS EXPOSURE BIOMARKERS

    EPA Science Inventory

    Alveolar breath sampling and analysis can be extremely useful in exposure assessment studies involving volatile organic compounds (VOCs). Over recent years scientists from the US Environmental Protection Agency's National Exposure Research Laboratory have developed and refined...

  20. Phenotypic profiling and gene expression analyses for aromatic and volatile compounds in Chamoes (Cucumis melo).

    PubMed

    Lee, Jeongyeo; Kim, Min Keun; Hwang, Seung Hwan; Kim, Jungeun; Ahn, Jong Moon; Min, Sung Ran; Park, Sang Un; Lim, Soon Sung; Kim, HyeRan

    2014-05-01

    Gotgam chamoe (GgC), a native oriental melon in Korea, is known to possess the aroma of a dried persimmon, an agronomic relevance for melon breeding program. The volatile compounds and the transcript levels of aromatic compound genes in cultivar (Ohbokggul chamoe [OC]) and GgC were profiled. A total of 62 volatile compounds were identified and quantified. Twenty-eight volatile compounds were specific to either the OC or the GgC. The amounts of volatile alcohol, saturated hydrocarbon, and unsaturated hydrocarbon compounds were 2.2, 2.7, and 1.1 times higher in OC, respectively. The amounts of ketone volatiles were 1.2 times higher in GgC, whereas the total amounts of esters were similar. In the shikimate pathway, transcriptional patterns with the fruit parts were different between the two chamoes for CmDAHPS, CmDHD/SDH, and CmEPSPS. The expression levels of all six genes investigated, especially CmCS, were highest in the peel of both chamoes compared to the other parts. The transcript levels of the aromatic amino acid biosynthesis genes demonstrate that phenylalanine and tyrosine are present more in edible parts of the chamoe, while tryptophan may be accumulated low in the chamoe. In addition, phenylalanine and tryptophan are synthesized more in GgC than the OC.

  1. Pseudomonas putida as a platform for the synthesis of aromatic compounds.

    PubMed

    Molina-Santiago, Carlos; Cordero, Baldo F; Daddaoua, Abdelali; Udaondo, Zulema; Manzano, Javier; Valdivia, Miguel; Segura, Ana; Ramos, Juan-Luis; Duque, Estrella

    2016-09-01

    Aromatic compounds such as l-phenylalanine, 2-phenylethanol and trans-cinnamate are aromatic compounds of industrial interest. Current trends support replacement of chemical synthesis of these compounds by 'green' alternatives produced in microbial cell factories. The solvent-tolerant Pseudomonas putida DOT-T1E strain was genetically modified to produce up to 1 g l-1 of l-phenylalanine. In order to engineer this strain, we carried out the following stepwise process: (1) we selected random mutants that are resistant to toxic phenylalanine analogues; (2) we then deleted up to five genes belonging to phenylalanine metabolism pathways, which greatly diminished the internal metabolism of phenylalanine; and (3) in these mutants, we overexpressed the pheAfbr gene, which encodes a recombinant variant of PheA that is insensitive to feedback inhibition by phenylalanine. Furthermore, by introducing new genes, we were able to further extend the diversity of compounds produced. Introduction of histidinol phosphate transferase (PP_0967), phenylpyruvate decarboxylase (kdc) and an alcohol dehydrogenase (adh) enabled the strain to produce up to 180 mg l-1 2-phenylethanol. When phenylalanine ammonia lyase (pal) was introduced, the resulting strain produced up to 200 mg l-1 of trans-cinnamate. These results demonstrate that P. putida can serve as a promising microbial cell factory for the production of l-phenylalanine and related compounds.

  2. PERFLUORINATED ORGANIC COMPOUND EXPOSURE ASSESSMENT RESEARCH

    EPA Science Inventory

    A wide range of perfluorinated organic compounds (PFCs) has been used in a variety of industrial processes and consumer products. The most commonly studied PFCs include perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA), but there are many more compounds in this c...

  3. (CHINA) PERFLUORINATED ORGANIC COMPOUND EXPOSURE ASSESSMENT RESEARCH

    EPA Science Inventory

    A wide range of perfluorinated organic compounds (PFCs) has been used in a variety of industrial processes and consumer products. The most commonly studied PFCs include perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA), but there are many more compounds in this c...

  4. Volatile organic compound emissions from silage systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    As a precursor to smog, emission of volatile organic compounds (VOCs) to the atmosphere is an environmental concern in some regions. The major source from farms is silage, with emissions coming from the silo face, mixing wagon, and feed bunk. The major compounds emitted are alcohols with other impor...

  5. VOLATILE ORGANIC COMPOUNDS (VOCS) CHAPTER 31.

    EPA Science Inventory

    The term "volatile organic compounds' (VOCs) was originally coined to refer, as a class, to carbon-containing chemicals that participate in photochemical reactions in the ambient (outdoor) are. The regulatory definition of VOCs used by the U.S. EPA is: Any compound of carbon, ex...

  6. Three-phase modeling of polycyclic aromatic hydrocarbon association with pore-water-dissolved organic carbon

    SciTech Connect

    Mitra, S. ); Dickhut, R.M. )

    1999-06-01

    Log-log plots of measured organic carbon-normalized sediment pore-water distribution coefficients (K[prime][sub OC]s) for several polycyclic aromatic hydrocarbons (PAHs) versus their octanol-water partition coefficients (K[prime][sub OW]s) at two sites in the Elizabeth River, Virginia, show large deviations from linearity. Organic-carbon normalized distribution coefficients for these PAHs between sediments and pore waters decreased by more than two orders of magnitude with depth as well. To determine to what extent pore water dissolved and colloidal organic carbon (DOC) was responsible for the observed nonlinearity and decrease in K[prime][sub OC], a three-phase model was used to estimate pore-water PAH-DOC binding coefficients (K[sub DOC]). Partitioning of PAHs to pore-water DOC (i.e., K[sub DOC])enhances the observed dissolved phase PAH concentration, especially for high-K[sub OW] compounds, contributing to the nonlinearity in K[prime][sub OC]-K[sub OW] plots. However, the application of the three-phase partitioning model to these data indicate that, at most, pore-water PAH-DOC binding accounts for one order of magnitude of the observed decrease in K[prime][sub OC] with depth in the sediment bed. The results of this study are consistent with three-phase partitioning theory for hydrophobic organic compounds between sediment organic matter, pore-water DOC, and freely dissolved aqueous phases in natural systems.

  7. Retardation effect of nitrogen compounds and condensed aromatics on shale oil catalytic cracking processing and their characterization.

    PubMed

    Li, Nan; Chen, Chen; Wang, Bin; Li, Shaojie; Yang, Chaohe; Chen, Xiaobo

    Untreated shale oil, shale oil treated with HCl aqueous solution and shale oil treated with HCl and furfural were used to do comparative experiments in fixed bed reactors. Nitrogen compounds and condensed aromatics extracted by HCl and furfural were characterized by electrospray ionization Fourier transform cyclotron resonance mass spectrometry and gas chromatography and mass spectrometry, respectively. Compared with untreated shale oil, the conversion and yield of liquid products increased considerably after removing basic nitrogen compounds by HCl extraction. Furthermore, after removing nitrogen compounds and condensed aromatics by both HCl and furfural, the conversion and yield of liquid products further increased. In addition, N1 class species are predominant in both basic and non-basic nitrogen compounds, and they are probably indole, carbazole, cycloalkyl-carbazole, pyridine and cycloalkyl-pyridine. As for the condensed aromatics, most of them possess aromatic rings with two to three rings and zero to four carbon atom.

  8. Manmade organic compounds in the surface waters of the United States; a review of current understanding

    USGS Publications Warehouse

    Smith, James A.; Witkowski, P.J.; Fusillo, Thomas V.

    1988-01-01

    This report reviews the occurrence and distribution of manmade organic compounds in the surface waters of the United States. On the basis of their aqueous solubilities, nonionic organic compounds partition themselves among water, dissolved organic matter, particulate organic matter, and the lipid reservoirs of aquatic organisms. Ionized organic compounds can be adsorbed to sediments, thereby reducing their aqueous concentrations. Transformation processes of photolysis, hydrolysis, biodegradation, and volatilization can attenuate organic compounds, and attenuation rates commonly follow a first-order kinetic process. Eight groups of manmade organic compounds are discussed: 1. Polychlorinated biphenyls and organochlorine insecticides, 2. Carbamate and organophosphorus insecticides, 3. Herbicides, 4. Phenols, 5. Halogenated aliphatic and monocyclic aromatic hydrocarbons, 6. Phthalate esters, 7. Polychlorinated dibenzo-p-dioxins, and 8. Polycyclic aromatic hydrocarbons. For each compound group, data pertaining to use, production, and properties are presented and discussed. Processes that influence the environmental fate of each group, as determined primarily through laboratory studies, are reviewed, and important fate processes are identified. Environmental concentrations of compounds from each group in water, biota, and sediment are given to demonstrate representative values for comparison with concentrations determined during ongoing research. Finally, where data are sufficient, regional and temporal contamination trends in the United States are discussed.

  9. Manmade organic compounds in the surface waters of the United States: a review of current understanding

    USGS Publications Warehouse

    Smith, James A.; Witkowski, Patrick J.; Fusillo, Thomas V.

    1987-01-01

    This report reviews the occurrence and distribution of manmade organic compounds in the surface waters of the United States. On the basis of their aqueous solubilities, nonionic organic compounds partition themselves between water, dissolved organic matter, particulate organic matter, and the lipid reservoirs of aquatic organisms. Ionized organic compounds can be absorbed to sediments, thereby reducing their aqueous concentrations. Transformation processes of photolysis, hydrolysis, biodegradation, and volatilization can attenuate organic compounds, and attenuation rate commonly follow a first-order kinetic process. Eight groups of manmade organic compounds are discussed: 1. Polychlorinated biphenyls and organochlorine insecticides, 2. Carbamate and organophosphorus insecticides, 3. Herbicides, 4. Phenols, 5. Halogenated aliphatic and monocyclic aromatic hydrocarbons, 6. Phthalate esters, 7. Polychlorinated dibenzo-p-dioxins, and 8. Polycyclic aromatic hydrocarbons. For each compound group, data pertaining to use, production, and properties are presented and discussed. Processes that influence that the environmental fate of each group, as determined primarily through laboratory studies, are reviewed, and important fate processes are identified. Environmental concentrations of compounds from each group in water, biota, and sediment are given to demonstrate representative values for comparison to concentrations determined during ongoing research. Finally, where sufficient data exist, regional and temporal contamination trends in the United States are discussed.

  10. Process for removing halogenated aliphatic and aromatic compounds from petroleum products. [Polychlorinated biphenyls; methylene chloride; perchloroethylene; trichlorofluoroethane; trichloroethylene; chlorobenzene

    DOEpatents

    Googin, J.M.; Napier, J.M.; Travaglini, M.A.

    1982-03-31

    A process for removing halogenated aliphatic and aromatic compounds, e.g., polychlorinated biphenyls, from petroleum products by solvent extraction. The halogenated aliphatic and aromatic compounds are extracted from a petroleum product into a polar solvent by contracting the petroleum product with the polar solvent. The polar solvent is characterized by a high solubility for the extracted halogenated aliphatic and aromatic compounds, a low solubility for the petroleum product and considerable solvent power for polyhydroxy compound. The preferred polar solvent is dimethylformamide. A miscible polyhydroxy compound, such as, water, is added to the polar extraction solvent to increase the polarity of the polar extraction solvent. The halogenated aliphatic and aromatic compounds are extracted from the highly-polarized mixture of polyhydroxy compound and polar extraction solvent into a low polar or nonpolar solvent by contacting the polyhydroxy compound-polar solvent mixture with the low polar or nonpolar solvent. The halogenated aliphatic and aromatic compounds in the low polar or nonpolar solvent by physical means, e.g., vacuum evaporation. The polar and nonpolar solvents are recovered for recycling. The process can easily be designed for continuous operation. Advantages of the process include that the polar solvent and a major portion of the nonpolar solvent can be recycled, the petroleum products are reclaimable and the cost for disposing of waste containing polychlorinated biphenyls is significantly reduced. 2 tables.

  11. A novel aromatic oil compound inhibits microbial overgrowth on feet: a case study

    PubMed Central

    Misner, Bill D

    2007-01-01

    Background Athlete's Foot (Tinea pedis) is a form of ringworm associated with highly contagious yeast-fungi colonies, although they look like bacteria. Foot bacteria overgrowth produces a harmless pungent odor, however, uncontrolled proliferation of yeast-fungi produces small vesicles, fissures, scaling, and maceration with eroded areas between the toes and the plantar surface of the foot, resulting in intense itching, blisters, and cracking. Painful microbial foot infection may prevent athletic participation. Keeping the feet clean and dry with the toenails trimmed reduces the incidence of skin disease of the feet. Wearing sandals in locker and shower rooms prevents intimate contact with the infecting organisms and alleviates most foot-sensitive infections. Enclosing feet in socks and shoes generates a moisture-rich environment that stimulates overgrowth of pungent both aerobic bacteria and infectious yeast-fungi. Suppression of microbial growth may be accomplished by exposing the feet to air to enhance evaporation to reduce moistures' growth-stimulating effect and is often neglected. There is an association between yeast-fungi overgrowths and disabling foot infections. Potent agents virtually exterminate some microbial growth, but the inevitable presence of infection under the nails predicts future infection. Topical antibiotics present a potent approach with the ideal agent being one that removes moisture producing antibacterial-antifungal activity. Severe infection may require costly prescription drugs, salves, and repeated treatment. Methods A 63-y female volunteered to enclose feet in shoes and socks for 48 hours. Aerobic bacteria and yeast-fungi counts were determined by swab sample incubation technique (1) after 48-hours feet enclosure, (2) after washing feet, and (3) after 8-hours socks-shoes exposure to a aromatic oil powder-compound consisting of arrowroot, baking soda, basil oil, tea tree oil, sage oil, and clove oil. Conclusion Application of this

  12. Laboratory Investigation of Organic Aerosol Formation from Aromatic Hydrocarbons

    DOE R&D Accomplishments Database

    Molina, Luisa T.; Molina, Mario J.; Zhang, Renyi

    2006-08-23

    Our work for this DOE funded project includes: (1) measurements of the kinetics and mechanism of the gas-phase oxidation reactions of the aromatic hydrocarbons initiated by OH; (2) measurements of aerosol formation from the aromatic hydrocarbons; and (3) theoretical studies to elucidate the OH-toluene reaction mechanism using quantum-chemical and rate theories.

  13. Enhancing trichloroethylene degradation using non-aromatic compounds as growth substrates.

    PubMed

    Kim, Seungjin; Hwang, Jeongmin; Chung, Jinwook; Bae, Wookeun

    2014-06-30

    The effect of non-aromatic compounds on the trichloroethylene (TCE) degradation of toluene-oxidizing bacteria were evaluated using Burkholderia cepacia G4 that expresses toluene 2-monooxygenase and Pseudomonas putida that expresses toluene dioxygenase. TCE degradation rates for B. cepacia G4 and P. putida with toluene alone as growth substrate were 0.144 and 0.123 μg-TCE/mg-protein h, respectively. When glucose, acetate and ethanol were fed as additional growth substrates, those values increased up to 0.196, 0.418 and 0.530 μg-TCE/mg-protein h, respectively for B. cepacia G4 and 0.319, 0.219 and 0.373 μg-TCE/mg-protein h, respectively for P. putida. In particular, the addition of ethanol resulted in a high TCE degradation rate regardless of the initial concentration. The use of a non-aromatic compound as an additional substrate probably enhanced the TCE degradation because of the additional supply of NADH that is consumed in co-metabolic degradation of TCE. Also, it is expected that the addition of a non-aromatic substrate can reduce the necessary dose of toluene and, subsequently, minimize the potential competitive inhibition upon TCE co-metabolism by toluene.

  14. Organic compounds in produced waters from coalbed natural gas wells in the Powder River Basin, Wyoming, USA

    USGS Publications Warehouse

    Orem, W.H.; Tatu, C.A.; Lerch, H.E.; Rice, C.A.; Bartos, T.T.; Bates, A.L.; Tewalt, S.; Corum, M.D.

    2007-01-01

    The organic composition of produced water samples from coalbed natural gas (CBNG) wells in the Powder River Basin, WY, sampled in 2001 and 2002 are reported as part of a larger study of the potential health and environmental effects of organic compounds derived from coal. The quality of CBNG produced waters is a potential environmental concern and disposal problem for CBNG producers, and no previous studies of organic compounds in CBNG produced water have been published. Organic compounds identified in the produced water samples included: phenols, biphenyls, N-, O-, and S-containing heterocyclic compounds, polycyclic aromatic hydrocarbons (PAHs), aromatic amines, various non-aromatic compounds, and phthalates. Many of the identified organic compounds (phenols, heterocyclic compounds, PAHs) are probably coal-derived. PAHs represented the group of organic compounds most commonly observed. Concentrations of total PAHs ranged up to 23 ??g/L. Concentrations of individual compounds ranged from about 18 to <0.01 ??g/L. Temporal variability of organic compound concentrations was documented, as two wells with relatively high organic compound contents in produced water in 2001 had much lower concentrations in 2002. In many areas, including the PRB, coal strata provide aquifers for drinking water wells. Organic compounds observed in produced water are also likely present in drinking water supplied from wells in the coal. Some of the organic compounds identified in the produced water samples are potentially toxic, but at the levels measured in these samples are unlikely to have acute health effects. The human health effects of low-level, chronic exposure to coal-derived organic compounds in drinking water are currently unknown. Continuing studies will evaluate possible toxic effects from low level, chronic exposure to coal-derived organic compounds in drinking water supplies.

  15. Production of aromatic compounds by metabolically engineered Escherichia coli with an expanded shikimate pathway.

    PubMed

    Koma, Daisuke; Yamanaka, Hayato; Moriyoshi, Kunihiko; Ohmoto, Takashi; Sakai, Kiyofumi

    2012-09-01

    Escherichia coli was metabolically engineered by expanding the shikimate pathway to generate strains capable of producing six kinds of aromatic compounds, phenyllactic acid, 4-hydroxyphenyllactic acid, phenylacetic acid, 4-hydroxyphenylacetic acid, 2-phenylethanol, and 2-(4-hydroxyphenyl)ethanol, which are used in several fields of industries including pharmaceutical, agrochemical, antibiotic, flavor industries, etc. To generate strains that produce phenyllactic acid and 4-hydroxyphenyllactic acid, the lactate dehydrogenase gene (ldhA) from Cupriavidus necator was introduced into the chromosomes of phenylalanine and tyrosine overproducers, respectively. Both the phenylpyruvate decarboxylase gene (ipdC) from Azospirillum brasilense and the phenylacetaldehyde dehydrogenase gene (feaB) from E. coli were introduced into the chromosomes of phenylalanine and tyrosine overproducers to generate phenylacetic acid and 4-hydroxyphenylacetic acid producers, respectively, whereas ipdC and the alcohol dehydrogenase gene (adhC) from Lactobacillus brevis were introduced to generate 2-phenylethanol and 2-(4-hydroxyphenyl)ethanol producers, respectively. Expression of the respective introduced genes was controlled by the T7 promoter. While generating the 2-phenylethanol and 2-(4-hydroxyphenyl)ethanol producers, we found that produced phenylacetaldehyde and 4-hydroxyphenylacetaldehyde were automatically reduced to 2-phenylethanol and 2-(4-hydroxyphenyl)ethanol by endogenous aldehyde reductases in E. coli encoded by the yqhD, yjgB, and yahK genes. Cointroduction and cooverexpression of each gene with ipdC in the phenylalanine and tyrosine overproducers enhanced the production of 2-phenylethanol and 2-(4-hydroxyphenyl)ethanol from glucose. Introduction of the yahK gene yielded the most efficient production of both aromatic alcohols. During the production of 2-phenylethanol, 2-(4-hydroxyphenyl)ethanol, phenylacetic acid, and 4-hydroxyphenylacetic acid, accumulation of some by

  16. Production of Aromatic Compounds by Metabolically Engineered Escherichia coli with an Expanded Shikimate Pathway

    PubMed Central

    Yamanaka, Hayato; Moriyoshi, Kunihiko; Ohmoto, Takashi; Sakai, Kiyofumi

    2012-01-01

    Escherichia coli was metabolically engineered by expanding the shikimate pathway to generate strains capable of producing six kinds of aromatic compounds, phenyllactic acid, 4-hydroxyphenyllactic acid, phenylacetic acid, 4-hydroxyphenylacetic acid, 2-phenylethanol, and 2-(4-hydroxyphenyl)ethanol, which are used in several fields of industries including pharmaceutical, agrochemical, antibiotic, flavor industries, etc. To generate strains that produce phenyllactic acid and 4-hydroxyphenyllactic acid, the lactate dehydrogenase gene (ldhA) from Cupriavidus necator was introduced into the chromosomes of phenylalanine and tyrosine overproducers, respectively. Both the phenylpyruvate decarboxylase gene (ipdC) from Azospirillum brasilense and the phenylacetaldehyde dehydrogenase gene (feaB) from E. coli were introduced into the chromosomes of phenylalanine and tyrosine overproducers to generate phenylacetic acid and 4-hydroxyphenylacetic acid producers, respectively, whereas ipdC and the alcohol dehydrogenase gene (adhC) from Lactobacillus brevis were introduced to generate 2-phenylethanol and 2-(4-hydroxyphenyl)ethanol producers, respectively. Expression of the respective introduced genes was controlled by the T7 promoter. While generating the 2-phenylethanol and 2-(4-hydroxyphenyl)ethanol producers, we found that produced phenylacetaldehyde and 4-hydroxyphenylacetaldehyde were automatically reduced to 2-phenylethanol and 2-(4-hydroxyphenyl)ethanol by endogenous aldehyde reductases in E. coli encoded by the yqhD, yjgB, and yahK genes. Cointroduction and cooverexpression of each gene with ipdC in the phenylalanine and tyrosine overproducers enhanced the production of 2-phenylethanol and 2-(4-hydroxyphenyl)ethanol from glucose. Introduction of the yahK gene yielded the most efficient production of both aromatic alcohols. During the production of 2-phenylethanol, 2-(4-hydroxyphenyl)ethanol, phenylacetic acid, and 4-hydroxyphenylacetic acid, accumulation of some by

  17. Activation of Ca2+ uptake and inhibition of reversal of the sarcoplasmic reticulum Ca2+ pump by aromatic compounds.

    PubMed

    Petretski, J H; Wolosker, H; de Meis, L

    1989-12-05

    The effects of aromatic compounds in sarcoplasmic reticulum Ca2+-ATPase were investigated. The solubility of the drugs in various organic solvents and water was measured. The ratio between the solubility in organic solvents and that in water (distribution coefficient) was used as an index of their hydrophobicity. The order found was triphenylphosphine greater than diphenylamine greater than 3-nitrophenol greater than 4-nitrophenol greater than 1,3-dihydroxybenzene. The effects observed on the Ca2+-ATPase were correlated with hydrophobicity of the drugs, activation and inhibition being obtained at a lower concentration the greater the distribution coefficient of the drug into organic solvent. In leaky vesicles, the effects of each compound on the ATPase activity varied depending on the Ca2+ concentration in the medium: it inhibited in the presence of 5 microM Ca2+ and activated when the Ca2+ concentration was raised to 2 mM. In intact vesicles, 3- and 4-nitrophenol, diphenylamine, and triphenylphosphine enhanced both the rate of ATP hydrolysis and the amount of Ca2+ accumulated by the vesicles. These four drugs inhibited Ca2+ uptake when ITP was used as substrate. 1,3-Dihydroxybenzene enhanced the amount of Ca2+ accumulated by the vesicles regardless of whether ATP or ITP was the substrate. All five compounds inhibited the phosphorylation of the enzyme by Pi, the efflux of Ca2+, and the synthesis of ATP measured during the reversal of the Ca2+ pump. The results indicate that the hydrophobic character of various organic compounds determines their access to sensitive domains of the membrane-bound calcium pump. Additional specific effects are then produced, depending on the structure of each compound.

  18. Constituents of volatile organic compounds of evaporating essential oil

    NASA Astrophysics Data System (ADS)

    Chiu, Hua-Hsien; Chiang, Hsiu-Mei; Lo, Cho-Ching; Chen, Ching-Yen; Chiang, Hung-Lung

    2009-12-01

    Essential oils containing aromatic compounds can affect air quality when used indoors. Five typical and popular essential oils—rose, lemon, rosemary, tea tree and lavender—were investigated in terms of composition, thermal characteristics, volatile organic compound (VOC) constituents, and emission factors. The activation energy was 6.3-8.6 kcal mol -1, the reaction order was in the range of 0.6-0.8, and the frequency factor was 0.01-0.24 min -1. Toluene, 1,2,3-trimethylbenzene, 1,2,4-trimethylbenzene, n-undecane, p-diethylbenzene and m-diethylbenzene were the predominant VOCs of evaporating gas of essential oils at 40 °C. In addition, n-undecane, p-diethylbenzene, 1,2,4-trimethylbenzene, m-diethylbenzene, and 1,2,3-trimethylbenzene revealed high emission factors during the thermogravimetric (TG) analysis procedures. The sequence of the emission factors of 52 VOCs (137-173 mg g -1) was rose ≈ rosemary > tea tree ≈ lemon ≈ lavender. The VOC group fraction of the emission factor of aromatics was 62-78%, paraffins were 21-37% and olefins were less than 1.5% during the TG process. Some unhealthy VOCs such as benzene and toluene were measured at low temperature; they reveal the potential effect on indoor air quality and human health.

  19. Aromatic-Hydroxyl Interaction of a Lignin Model Compound on SBA-15, Present at Pyrolysis Temperatures

    DOE PAGES

    Kandziolka, III, Michael V.; Kidder, Michelle; Gill, Lance W.; ...

    2014-07-14

    An aromatic alpha-aryl ether compound (a benzyl phenyl ether analogue) was covalently grafted to mesoporous silica SBA-15, to create BPEa-SBA-15. The BPEa-SBA-15 was subjected to successive heating cycles up to 600 °C, with in situ monitoring by DRIFTS. It was found that the toluene moiety coordinates to SBA-15 surface silanol hydroxyl groups via an aromatic–hydroxyl interaction. This interaction is evidenced by a red-shift of the aromatic C–H stretches, as well as a red-shift and broadening of the surface hydroxyl O–H stretches, which are features characteristic of a hydrogen bond. These features remain present during heating until ~400 °C whereupon themore » ether linkage of BPEa-SBA-15 is cleaved, accompanied by loss of the toluene moiety.« less

  20. Aromatic-Hydroxyl Interaction of a Lignin Model Compound on SBA-15, Present at Pyrolysis Temperatures

    SciTech Connect

    Kandziolka, III, Michael V.; Kidder, Michelle; Gill, Lance W.; Wu, Zili; Savara, Aditya Ashi

    2014-07-14

    An aromatic alpha-aryl ether compound (a benzyl phenyl ether analogue) was covalently grafted to mesoporous silica SBA-15, to create BPEa-SBA-15. The BPEa-SBA-15 was subjected to successive heating cycles up to 600 °C, with in situ monitoring by DRIFTS. It was found that the toluene moiety coordinates to SBA-15 surface silanol hydroxyl groups via an aromatic–hydroxyl interaction. This interaction is evidenced by a red-shift of the aromatic C–H stretches, as well as a red-shift and broadening of the surface hydroxyl O–H stretches, which are features characteristic of a hydrogen bond. These features remain present during heating until ~400 °C whereupon the ether linkage of BPEa-SBA-15 is cleaved, accompanied by loss of the toluene moiety.

  1. Possible complex organic compounds on Mars.

    PubMed

    Kobayashi, K; Sato, T; Kajishima, S; Kaneko, T; Ishikawa, Y; Saito, T

    1997-01-01

    It is suggested that primitive Mars had somehow similar environments as primitive Earth. If life was born on the primitive earth using organic compounds which were produced from the early Earth environment, the same types of organic compounds were also formed on primitive Mars. Such organic compounds might have been preserved on Mars still now. We are studying possible organic formation on primitive and present Mars. A gaseous mixture of CO2, CO, N2 and H2O with various mixing ratios were irradiated with high energy protons (major components of cosmic rays). Hydrogen cyanide and formaldehyde were detected among volatile products, and yellow-brown-colored water-soluble non-volatile substances were produced, which gave amino acids after acid-hydrolysis. Major part of "amino acid precursors" were not simple molecules like aminonitriles, but complex compounds which eluted earlier than free amino acids in cation-exchange HPLC. These organic compounds should be major targets in the future Mars mission. Strategy for the detection of the complex organics on Mars will be discussed.

  2. Transition-Metal Planar Boron Clusters: a New Class of Aromatic Compounds with High Coordination

    NASA Astrophysics Data System (ADS)

    Wang, Lai-Sheng

    2012-06-01

    Photoelectron spectroscopy in combination with computational studies over the past decade has shown that boron clusters possess planar or quasi-planar structures, in contrast to that of bulk boron, which is dominated by three-dimensional cage-like building blocks. All planar or quasi-planar boron clusters are observed to consist of a monocyclic circumference with one or more interior atoms. The propensity for planarity has been found to be due to both σ and π electron delocalization throughout the molecular plane, giving rise to concepts of σ and π double aromaticity. We have found further that the central boron atoms can be substituted by transition metal atoms to form a new class of aromatic compounds, which consist of a central metal atom and a monocyclic boron ring (M B_n). Eight-, nine-, and ten-membered rings of boron have been observed, giving rise to octa-, ennea-, and deca-coordinated aromatic transition metal compounds [1-3]. References: [1] ``Aromatic Metal-Centered Monocyclic Boron Rings: Co B_9^- and Ru B_9^-" (Constantin Romanescu, Timur R. Galeev, Wei-Li Li, A. I. Boldyrev, and L. S. Wang), Angew. Chem. Int. Ed. {50}, 9334-9337 (2011). [2] ``Transition-Metal-Centered Nine-Membered Boron Rings: M B_9 and M B_9^- (M = Rh, Ir)" (Wei-Li Li, Constantin Romanescu, Timur R. Galeev, Zachary Piazza, A. I. Boldyrev, and L. S. Wang), J. Am. Chem. Soc. {134}, 165-168 (2012). [3] ``Observation of the Highest Coordination Number in Planar Species: Decacoordinated Ta B10^- and Nb B_9^- Anions" (Timur R. Galeev, Constantin Romanescu, Wei-Li Li, L. S. Wang, and A. I. Boldyrev), Angew. Chem. Int. Ed. {51}, 2101-2105 (2012).

  3. Photocatalytic oxidation of organic compounds on Mars

    NASA Technical Reports Server (NTRS)

    Chun, S. F. S.; Pang, K. D.; Cutts, J. A.; Ajello, J. M.

    1978-01-01

    Ultraviolet-stimulated catalytic oxidation is proposed as a mechanism for the destruction of organic compounds on Mars. The process involves the presence of gaseous oxygen, UV radiation, and a catalyst (titanium dioxide), and all three of these have been found to be present in the Martian environment. Therefore it seems plausible that UV-stimulated oxidation of organics is responsible for degrading organic molecules into inorganic end products.

  4. Bioactive compounds derived from the yeast metabolism of aromatic amino acids during alcoholic fermentation.

    PubMed

    Mas, Albert; Guillamon, Jose Manuel; Torija, Maria Jesus; Beltran, Gemma; Cerezo, Ana B; Troncoso, Ana M; Garcia-Parrilla, M Carmen

    2014-01-01

    Metabolites resulting from nitrogen metabolism in yeast are currently found in some fermented beverages such as wine and beer. Their study has recently attracted the attention of researchers. Some metabolites derived from aromatic amino acids are bioactive compounds that can behave as hormones or even mimic their role in humans and may also act as regulators in yeast. Although the metabolic pathways for their formation are well known, the physiological significance is still far from being understood. The understanding of this relevance will be a key element in managing the production of these compounds under controlled conditions, to offer fermented food with specific enrichment in these compounds or even to use the yeast as nutritional complements.

  5. Interaction of aromatic compounds with Photobacterium leiognathi luciferase: fluorescence anisotropy study.

    PubMed

    Kudryasheva, N S; Nemtseva, E V; Visser, A J W G; Van Hoek, A

    2003-01-01

    The time-resolved and steady-state fluorescence techniques were employed to elucidate possible interactions of four aromatic compounds (anthracene, POPOP, MSB and 1,4-naphthalendiol) with bacterial luciferase. Fluorescence spectra and fluorescence anisotropy decays of these compounds were studied in ethanol, water-ethanol solutions and in the presence of bacterial luciferase. Shifts of fluorescent spectra and differences in rotational correlation times are interpreted in terms of weak (hydrophobic) interactions of the molecules with the enzyme. These interactions suggest the feasibility of intermolecular energy transfer by an exchange resonance mechanism with a collision-interaction radius as a way of excitation of these compounds in the reaction catalysed by bacterial luciferase.

  6. Bioactive Compounds Derived from the Yeast Metabolism of Aromatic Amino Acids during Alcoholic Fermentation

    PubMed Central

    Guillamon, Jose Manuel; Torija, Maria Jesus; Beltran, Gemma; Troncoso, Ana M.; Garcia-Parrilla, M. Carmen

    2014-01-01

    Metabolites resulting from nitrogen metabolism in yeast are currently found in some fermented beverages such as wine and beer. Their study has recently attracted the attention of researchers. Some metabolites derived from aromatic amino acids are bioactive compounds that can behave as hormones or even mimic their role in humans and may also act as regulators in yeast. Although the metabolic pathways for their formation are well known, the physiological significance is still far from being understood. The understanding of this relevance will be a key element in managing the production of these compounds under controlled conditions, to offer fermented food with specific enrichment in these compounds or even to use the yeast as nutritional complements. PMID:24895623

  7. Reflectance spectroscopy of organic compounds: 1. Alkanes

    USGS Publications Warehouse

    Clark, R.N.; Curchin, J.M.; Hoefen, T.M.; Swayze, G.A.

    2009-01-01

    Reflectance spectra of the organic compounds comprising the alkane series are presented from the ultraviolet to midinfrared, 0.35 to 15.5 /??m. Alkanes are hydrocarbon molecules containing only single carbon-carbon bonds, and are found naturally on the Earth and in the atmospheres of the giant planets and Saturn's moon, Titan. This paper presents the spectral properties of the alkanes as the first in a series of papers to build a spectral database of organic compounds for use in remote sensing studies. Applications range from mapping the environment on the Earth, to the search for organic molecules and life in the solar system and throughout the. universe. We show that the spectral reflectance properties of organic compounds are rich, with major diagnostic spectral features throughout the spectral range studied. Little to no spectral change was observed as a function of temperature and only small shifts and changes in the width of absorption bands were observed between liquids and solids, making remote detection of spectral properties throughout the solar system simpler. Some high molecular weight organic compounds contain single-bonded carbon chains and have spectra similar to alkanes even ' when they fall into other families. Small spectral differences are often present allowing discrimination among some compounds, further illustrating the need to catalog spectral properties for accurate remote sensing identification with spectroscopy.

  8. Identification and Quantification of Volatile Organic Compounds at a Dairy

    NASA Astrophysics Data System (ADS)

    Filipy, J.; Mount, G.; Westberg, H.; Rumburg, B.

    2003-12-01

    Livestock operations in the United States are an escalating environmental concern. The increasing density of livestock within a farm results in an increased emission of odorous gases, which have gained considerable attention by the public in recent years (National Research Council (NRC), 2002). Odorous compounds such as ammonia (NH3), volatile organic compounds (VOC's), and hydrogen sulfide (H2S) were reported to have a major effect on the quality of life of local residents living near livestock facilities (NRC, 2002). There has been little data collected related to identification and quantification of gaseous compounds collected from open stall dairy operations in the United States. The research to be presented identifies and quantifies VOCs produced from a dairy operation that contribute to odor and other air quality problems. Many different VOCs were identified in the air downwind of an open lactating cow stall area and near a waste lagoon at the Washington State University dairy using Gas Chromatography Mass Spectroscopy (GC-MS) analysis techniques. Identified compounds were very diverse and included many alcohols, aldehydes, amines, aromatics, esters, ethers, a fixed gas, halogenated hydrocarbons, hydrocarbons, ketones, other nitrogen containing compounds, sulfur containing compounds, and terpenes. The VOCs directly associated with cattle waste were dependent on ambient temperature, with the highest emissions produced during the summer months. Low to moderate wind speeds were ideal for VOC collection. Concentrations of quantified compounds were mostly below odor detection thresholds found in the literature, however the combined odor magnitude of the large number of compounds detected was most likely above any minimum detection threshold.

  9. Factors that influence the response of the LysR type transcriptional regulators to aromatic compounds

    PubMed Central

    2011-01-01

    Background The transcriptional regulators DntR, NagR and NtdR have a high sequence identity and belong to the large family of LysR type transcriptional regulators (LTTRs). These three regulators are all involved in regulation of genes identified in pathways for degradation of aromatic compounds. They activate the transcription of these genes in the presence of an inducer, but the inducer specificity profiles are different. Results The results from this study show that NtdR has the broadest inducer specificity, responding to several nitro-aromatic compounds. Mutational studies of residues that differ between DntR, NagR and NtdR suggest that a number of specific residues are involved in the broader inducer specificity of NtdR when compared to DntR and NagR. The inducer response was also investigated as a function of the experimental conditions and a number of parameters such as the growth media, plasmid arrangement of the LTTR-encoding genes, promoter and gfp reporter gene, and the presence of a His6-tag were shown to affect the inducer response in E.coli DH5α. Furthermore, the response upon addition of both salicylate and 4-nitrobenzoate to the growth media was larger than the sum of responses upon addition of each of the compounds, which suggests the presence of a secondary binding site, as previously reported for other LTTRs. Conclusions Optimization of the growth conditions and gene arrangement resulted in improved responses to nitro-aromatic inducers. The data also suggests the presence of a previously unknown secondary binding site in DntR, analogous to that of BenM. PMID:21884597

  10. Origin of organic compounds in carbonaceous chondrites

    NASA Astrophysics Data System (ADS)

    Cronin, J. R.

    Carbonaceous chondrites, a class of primitive meteorite, have long been known to contain their complement of carbon largely in the form of organic, i.e., hydrocarbon-related, matter. Both discrete organic compounds and an insoluble, macromolecular material are present. Several characteristics of these materials provide evidence for their abiotic origin. The principal formation hypothesis have invoked chemistry occurring either in the solar nebula or on the parent body. However, recent stable isotope analyses of the meteorite carboxylic acids and amino acids indicate that they may be related to interstellar cloud compounds. These results suggest a formation scheme in which interstellar compounds were incorporated into the parent body and subsequently converted to the present suite of meteorite organics by the hydrothermal process believed to have formed the clay minerals of the meteorite matrix.

  11. Analyzing method on biogenic volatile organic compounds

    NASA Astrophysics Data System (ADS)

    Bai, J. H.; Wang, M. X.; Hu, F.; Greenberg, J. P.; Guenther, A. B.

    2002-02-01

    In order to analyze biogenic volatile organic compounds in the atmosphere, an automated gas chromatography is developed and employed at the laboratory of National Center for Atmospheric Research (NCAR) during January to July, 2000. A small refrigerator was used so as to remove water in the air sample from gas line, and get accurate concentrations of volatile organic compounds. At 5degreesC, good water removing efficiency can be obtained at controlled flow rate. Air samples were collected around the building of Mesa Lab. of NCAR and analyzed by this gas chromatography system. This paper reports this gas chromatography system and results of air samples. The experimental results show that this gas chromatography system has a good reproducibility and stability, and main interesting volatile organic compounds such as isoprene, monoterpenes have an evident diurnal variation.

  12. Catalyst for Oxidation of Volatile Organic Compounds

    NASA Technical Reports Server (NTRS)

    Wood, George M. (Inventor); Upchurch, Billy T. (Inventor); Schryer, David R. (Inventor); Davis, Patricia P. (Inventor); Kielin, Erik J. (Inventor); Brown, Kenneth G. (Inventor); Schyryer, Jacqueline L. (Inventor); DAmbrosia, Christine M. (Inventor)

    2000-01-01

    Disclosed is a process for oxidizing volatile organic compounds to carbon dioxide and water with the minimal addition of energy. A mixture of the volatile organic compound and an oxidizing agent (e.g. ambient air containing the volatile organic compound) is exposed to a catalyst which includes a noble metal dispersed on a metal oxide which possesses more than one oxidation state. Especially good results are obtained when the noble metal is platinum, and the metal oxide which possesses more than one oxidation state is tin oxide. A promoter (i.e., a small amount of an oxide of a transition series metal) may be used in association with the tin oxide to provide very beneficial results.

  13. Treatment of sludge containing nitro-aromatic compounds in reed-bed mesocosms - Water, BOD, carbon and nutrient removal

    SciTech Connect

    Gustavsson, L.; Engwall, M.

    2012-01-15

    Highlights: Black-Right-Pointing-Pointer It is necessary to improve existing and develop new sludge management techniques. Black-Right-Pointing-Pointer One method is dewatering and biodegradation of compounds in constructed wetlands. Black-Right-Pointing-Pointer The result showed high reduction of all tested parameters after treatment. Black-Right-Pointing-Pointer Plants improve degradation and Phragmites australis is tolerant to xenobiotics. Black-Right-Pointing-Pointer The amount of sludge could be reduced by 50-70%. - Abstract: Since the mid-1970s, Sweden has been depositing 1 million ton d.w sludge/year, produced at waste water treatment plants. Due to recent legislation this practice is no longer a viable method of waste management. It is necessary to improve existing and develop new sludge management techniques and one promising alternative is the dewatering and treatment of sludge in constructed wetlands. The aim of this study was to follow reduction of organic carbon, BOD and nutrients in an industrial sludge containing nitro-aromatic compounds passing through constructed small-scale wetlands, and to investigate any toxic effect such as growth inhibition of the common reed Phragmites australis. The result showed high reduction of all tested parameters in all the outgoing water samples, which shows that constructed wetlands are suitable for carbon and nutrient removal. The results also showed that P. australis is tolerant to xenobiotics and did not appear to be affected by the toxic compounds in the sludge. The sludge residual on the top of the beds contained low levels of organic carbon and is considered non-organic and could therefore be landfilled. Using this type of secondary treatment method, the amount of sludge could be reduced by 50-70%, mainly by dewatering and biodegradation of organic compounds.

  14. Flash Vacuum Pyrolysis of Lignin Model Compounds: Reaction Pathways of Aromatic Methoxy Groups

    SciTech Connect

    Britt, P.F.; Buchanan, A.C., III; Martineau, D.R.

    1999-03-21

    Currently, there is interest in utilizing lignin, a major constituent of biomass, as a renewable source of chemicals and fuels. High yields of liquid products can be obtained from the flash or fast pyrolysis of biomass, but the reaction pathways that lead to product formation are not understood. To provide insight into the primary reaction pathways under process relevant conditions, we are investigating the flash vacuum pyrolysis (FVP) of lignin model compounds at 500 C. This presentation will focus on the FVP of {beta}-ether linkages containing aromatic methoxy groups and the reaction pathways of methoxy-substituted phenoxy radicals.

  15. Sono-bromination of aromatic compounds based on the ultrasonic advanced oxidation processes.

    PubMed

    Fujita, Mitsue; Lévêque, Jean-Marc; Komatsu, Naoki; Kimura, Takahide

    2015-11-01

    A novel, mild "sono-halogenation" of various aromatic compounds with potassium halide was investigated under ultrasound in a biphasic carbon tetrachloride/water medium. The feasibility study was first undertaken with the potassium bromide and then extended to chloride and iodide analogues. This methodology could be considered as a new expansion of the ultrasonic advanced oxidation processes (UAOPs) into a synthetic aspect as the developed methodology is linked to the sonolytic disappearance of carbon tetrachloride. Advantages of the present method are not only that the manipulation of the bromination is simple and green, but also that the halogenating agents used are readily available, inexpensive, and easy-handling.

  16. Catalytic oxidation of volatile organic compounds (VOCs) - A review

    NASA Astrophysics Data System (ADS)

    Kamal, Muhammad Shahzad; Razzak, Shaikh A.; Hossain, Mohammad M.

    2016-09-01

    Emission of volatile organic compounds (VOCs) is one of the major contributors to air pollution. The main sources of VOCs are petroleum refineries, fuel combustions, chemical industries, decomposition in the biosphere and biomass, pharmaceutical plants, automobile industries, textile manufacturers, solvents processes, cleaning products, printing presses, insulating materials, office supplies, printers etc. The most common VOCs are halogenated compounds, aldehydes, alcohols, ketones, aromatic compounds, and ethers. High concentrations of these VOCs can cause irritations, nausea, dizziness, and headaches. Some VOCs are also carcinogenic for both humans and animals. Therefore, it is crucial to minimize the emission of VOCs. Among the available technologies, the catalytic oxidation of VOCs is the most popular because of its versatility of handling a range of organic emissions under mild operating conditions. Due to that fact, there are numerous research initiatives focused on developing advanced technologies for the catalytic destruction of VOCs. This review discusses recent developments in catalytic systems for the destruction of VOCs. Review also describes various VOCs and their sources of emission, mechanisms of catalytic destruction, the causes of catalyst deactivation, and catalyst regeneration methods.

  17. Antioxidant and Anti-Osteoporotic Activities of Aromatic Compounds and Sterols from Hericium erinaceum.

    PubMed

    Li, Wei; Lee, Sang Hyun; Jang, Hae Dong; Ma, Jin Yeul; Kim, Young Ho

    2017-01-11

    Hericium erinaceum, commonly called lion's mane mushroom, is a traditional edible mushroom widely used in culinary applications and herbal medicines in East Asian countries. In this study, a new sterol, cerevisterol 6-cinnamate (6), was isolated from the fruiting bodies of H. erinaceum together with five aromatic compounds 1-5 and five sterols 7-11. The chemical structures of these compounds were elucidated using chemical and physical methods and comparison of HRESIMS, ¹D-NMR (¹H, (13)C, and DEPT) and 2D-NMR (COSY, HMQC, HMBC, and NOESY) spectra with previously reported data. The antioxidant and anti-osteoporotic activities of extracts and the isolated compounds 1-11 were investigated. All compounds exhibited peroxyl radical-scavenging capacity but only compounds 1, 3, and 4 showed potent reducing capacity. Moreover, compounds 1, 2, 4, and 5 showed moderate effects on cellular antioxidant activity and inhibited the receptor activator of nuclear factor κB ligand (RANKL)-induced osteoclastic differentiation. These results suggested that H. erinaceum could be utilized in the development of natural antioxidant and anti-osteoporotic nutraceuticals and functional foods.

  18. Kinetics of oxidation of aliphatic and aromatic thiols by myeloperoxidase compounds I and II.

    PubMed

    Burner, U; Jantschko, W; Obinger, C

    1999-01-29

    Myeloperoxidase (MPO) is the most abundant protein in neutrophils and plays a central role in microbial killing and inflammatory tissue damage. Because most of the non-steroidal anti-inflammatory drugs and other drugs contain a thiol group, it is necessary to understand how these substrates are oxidized by MPO. We have performed transient kinetic measurements to study the oxidation of 14 aliphatic and aromatic mono- and dithiols by the MPO intermediates, Compound I (k3) and Compound II (k4), using sequential mixing stopped-flow techniques. The one-electron reduction of Compound I by aromatic thiols (e.g. methimidazole, 2-mercaptopurine and 6-mercaptopurine) varied by less than a factor of seven (between 1.39 +/- 0.12 x 10(5) M(-1) s(-1) and 9.16 +/- 1.63 x 10(5) M(-1) s(-1)), whereas reduction by aliphatic thiols was demonstrated to depend on their overall net charge and hydrophobic character and not on the percentage of thiol deprotonation or redox potential. Cysteamine, cysteine methyl ester, cysteine ethyl ester and alpha-lipoic acid showed k3 values comparable to aromatic thiols, whereas a free carboxy group (e.g. cysteine, N-acetylcysteine, glutathione) diminished k3 dramatically. The one-electron reduction of Compound II was far more constrained by the nature of the substrate. Reduction by methimidazole, 2-mercaptopurine and 6-mercaptopurine showed second-order rate constants (k4) of 1.33 +/- 0.08 x 10(5) M(-1) s(-1), 5.25 +/- 0.07 x 10(5) M(-1) s(-1) and 3.03 +/- 0.07 x 10(3) M(-1) s(-1). Even at high concentrations cysteine, penicillamine and glutathione could not reduce Compound II, whereas cysteamine (4.27 +/- 0.05 x 10(3) M(-1) s(-1)), cysteine methyl ester (8.14 +/- 0.08 x 10(3) M(-1) s(-1)), cysteine ethyl ester (3.76 +/- 0.17 x 10(3) M(-1) s(-1)) and alpha-lipoic acid (4.78 +/- 0.07 x 10(4) M(-1) s(-1)) were demonstrated to reduce Compound II and thus could be expected to be oxidized by MPO without co-substrates.

  19. Comparison of HPLC-MS interfaces in the determination of heterocyclic polycyclic aromatic compounds

    SciTech Connect

    Thomas, D.; Sim, P.G.; Benoit, F.M.

    1995-12-31

    Polycyclic aromatic compounds (PACs) are generally regarded as one of the most widely disseminated groups of chemical carcinogens. In this work, the authors are interested in the determination of some of the heteroatom substituted PACs, particularly those containing nitrogen (PANHs) or sulfur (PASHs) in the aromatic ring structure. The reason for interest in these compounds is the extreme carcinogenicity of many of them. Further, the relative carcinogenicity can vary markedly between different members of a set of isomeric compounds. Any reliable assessment of the hazards associated with exposure to mixtures of PACs must, therefore, include analysis of the levels of these compounds in the mixture. The analytical technique used must also yield information about the relative amounts of different isomeric compounds. The sample chosen for this study is an extract of PACs from the Sydney Tar Ponds, Sydney, Nova Scotia, Canada. The Tar Ponds represent the end result of approximately 80 years of the uncontrolled discharge of effluent from an industrial coking operation into a tidal lagoon. It is thus a rich source of PAC mixtures. In the present work, the authors have applied two HPLC-MS methods to the characterization of the PASH content of tar pond sample fractions. The methods differed in the nature of the interface between the HPLC and the MS, and in the ionization process. The two techniques studied were the moving belt with EI ionization, and the heated nebulizer with APCI. Comparison was made on the basis of a number of criteria, including ease of use (and of automation), quality of mass spectra provided, preservation of chromatographic integrity, and sensitivity.

  20. Biogeochemical processes governing exposure and uptake of organic pollutant compounds in aquatic organisms.

    PubMed Central

    Farrington, J W

    1991-01-01

    This paper reviews current knowledge of biogeochemical cycles of pollutant organic chemicals in aquatic ecosystems with a focus on coastal ecosystems. There is a bias toward discussing chemical and geochemical aspects of biogeochemical cycles and an emphasis on hydrophobic organic compounds such as polynuclear aromatic hydrocarbons, polychlorinated biphenyls, and chlorinated organic compounds used as pesticides. The complexity of mixtures of pollutant organic compounds, their various modes of entering ecosystems, and their physical chemical forms are discussed. Important factors that influence bioavailability and disposition (e.g., organism-water partitioning, uptake via food, food web transfer) are reviewed. These factors include solubilities of chemicals; partitioning of chemicals between solid surfaces, colloids, and soluble phases; variables rates of sorption, desorption; and physiological status of organism. It appears that more emphasis on considering food as a source of uptake and bioaccumulation is important in benthic and epibenthic ecosystems when sediment-associated pollutants are a significant source of input to an aquatic ecosystem. Progress with mathematical models for exposure and uptake of contaminant chemicals is discussed briefly. PMID:1904812

  1. Mineral dust aerosols promote the formation of toxic nitropolycyclic aromatic compounds

    PubMed Central

    Kameda, Takayuki; Azumi, Eri; Fukushima, Aki; Tang, Ning; Matsuki, Atsushi; Kamiya, Yuta; Toriba, Akira; Hayakawa, Kazuichi

    2016-01-01

    Atmospheric nitrated polycyclic aromatic hydrocarbons (NPAHs), which have been shown to have adverse health effects such as carcinogenicity, are formed in part through nitration reactions of their parent polycyclic aromatic hydrocarbons (PAHs) in the atmosphere. However, little is known about heterogeneous nitration rates of PAHs by gaseous NO2 on natural mineral substrates, such as desert dust aerosols. Herein by employing kinetic experiments using a flow reactor and surface analysis by Fourier transform infrared spectroscopy with pyridine adsorption, we demonstrate that the reaction is accelerated on acidic surfaces of mineral dust, particularly on those of clay minerals. In support of this finding, we show that levels of ambient particle-associated NPAHs in Beijing, China, significantly increased during heavy dust storms. These results suggest that mineral dust surface reactions are an unrecognized source of toxic organic chemicals in the atmosphere and that they enhance the toxicity of mineral dust aerosols in urban environments. PMID:27075250

  2. Mineral dust aerosols promote the formation of toxic nitropolycyclic aromatic compounds

    NASA Astrophysics Data System (ADS)

    Kameda, Takayuki; Azumi, Eri; Fukushima, Aki; Tang, Ning; Matsuki, Atsushi; Kamiya, Yuta; Toriba, Akira; Hayakawa, Kazuichi

    2016-04-01

    Atmospheric nitrated polycyclic aromatic hydrocarbons (NPAHs), which have been shown to have adverse health effects such as carcinogenicity, are formed in part through nitration reactions of their parent polycyclic aromatic hydrocarbons (PAHs) in the atmosphere. However, little is known about heterogeneous nitration rates of PAHs by gaseous NO2 on natural mineral substrates, such as desert dust aerosols. Herein by employing kinetic experiments using a flow reactor and surface analysis by Fourier transform infrared spectroscopy with pyridine adsorption, we demonstrate that the reaction is accelerated on acidic surfaces of mineral dust, particularly on those of clay minerals. In support of this finding, we show that levels of ambient particle-associated NPAHs in Beijing, China, significantly increased during heavy dust storms. These results suggest that mineral dust surface reactions are an unrecognized source of toxic organic chemicals in the atmosphere and that they enhance the toxicity of mineral dust aerosols in urban environments.

  3. Mineral dust aerosols promote the formation of toxic nitropolycyclic aromatic compounds.

    PubMed

    Kameda, Takayuki; Azumi, Eri; Fukushima, Aki; Tang, Ning; Matsuki, Atsushi; Kamiya, Yuta; Toriba, Akira; Hayakawa, Kazuichi

    2016-04-14

    Atmospheric nitrated polycyclic aromatic hydrocarbons (NPAHs), which have been shown to have adverse health effects such as carcinogenicity, are formed in part through nitration reactions of their parent polycyclic aromatic hydrocarbons (PAHs) in the atmosphere. However, little is known about heterogeneous nitration rates of PAHs by gaseous NO2 on natural mineral substrates, such as desert dust aerosols. Herein by employing kinetic experiments using a flow reactor and surface analysis by Fourier transform infrared spectroscopy with pyridine adsorption, we demonstrate that the reaction is accelerated on acidic surfaces of mineral dust, particularly on those of clay minerals. In support of this finding, we show that levels of ambient particle-associated NPAHs in Beijing, China, significantly increased during heavy dust storms. These results suggest that mineral dust surface reactions are an unrecognized source of toxic organic chemicals in the atmosphere and that they enhance the toxicity of mineral dust aerosols in urban environments.

  4. Influence of carbonization methods on the aromaticity of pyrogenic dissolved organic carbon

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Dissolved organic carbon (DOC) components of soil amendments such as biochar will influence the fundamental soil chemistry including the metal speciation, nutrient availability, and microbial activity. Quantitative correlation is necessary between (i) pyrogenic DOC components of varying aromaticity...

  5. Modeling the Role of Alkanes, Polycyclic Aromatic Hydrocarbons, and Their Oligomers in Secondary Organic Aerosol Formation

    EPA Science Inventory

    A computationally efficient method to treat secondary organic aerosol (SOA) from various length and structure alkanes as well as SOA from polycyclic aromatic hydrocarbons (PAHs) is implemented in the Community Multiscale Air Quality (CMAQ) model to predict aerosol concentrations ...

  6. Organic waste compounds as contaminants in Milwaukee-area streams

    USGS Publications Warehouse

    Baldwin, Austin K.; Corsi, Steven R.; Magruder, Christopher; Magruder, Matthew; Bruce, Jennifer L.

    2015-09-22

    Organic waste compounds (OWCs) are ingredients and by-products of common agricultural, industrial, and household substances that can contaminate our streams through sources like urban runoff, sewage overflows, and leaking septic systems. To better understand how OWCs are affecting Milwaukee-area streams, the U.S. Geological Survey, in cooperation with the Milwaukee Metropolitan Sewerage District, conducted a three-year study to investigate the presence and potential toxicity of 69 OWCs in base flow, stormflow, pore water, and sediment at 14 stream sites and 3 Milwaukee harbor locations. This fact sheet summarizes the major findings of this study, including detection frequencies and concentrations, potential toxicity, the prevalence of polycyclic aromatic hydrocarbons (PAHs), and the influence of urbanization.

  7. Chlorinated organic compounds in urban river sediments

    SciTech Connect

    Soma, Y.; Shiraishi, H.; Inaba, K.

    1995-12-31

    Among anthropogenic chemicals, many chlorinated organic compounds have been used as insecticides and detected frequently as contaminants in urban river sediments so far. However, the number and total amount of chemicals produced commercially and used are increasing year by year, though each amount of chemicals is not so high. New types of contaminants in the environment may be detected by the use of newly developed chemicals. Chlorinated organic compounds in the urban river sediments around Tokyo and Kyoto, large cities in Japan, were surveyed and recent trends of contaminants were studied. Contaminants of the river sediments in industrial areas had a variety, but PCB (polychlorinated biphenyls) was detected in common in industrial areas. Concentration of PCB related well to the number of factories on both sides of rivers, although the use of PCB was stopped 20 years ago. In domestic areas, Triclosan (5-chloro-2-(2,4-dichlorophenoxy)-phenol) and Triclocarban (3,4,4{prime}-trichlorocarbanilide)(both are contained in soap or shampoo for fungicides), p-dichlorobenzene (insecticides for wears) and TCEP(tris-chloroethyl phosphate) were detected. EOX(extracted organic halogen) in the sediments was 5 to 10 times of chlorinated organic compounds detected by GC/MS. Major part of organic halogen was suggested to be included in chlorinated organics formed by bleaching or sterilization.

  8. Coupled LC-GC techniques for the characterisation of polycyclic aromatic compounds in fuel materials

    SciTech Connect

    Askey, S.A.; Holden, K.M.L.; Bartle, K.D.

    1995-12-31

    Exposure to polycyclic aromatic compounds (PAC) has long been identified as of considerable environmental concern. Originating from both natural and anthropogenic sources, many PAC exhibit significant carcinogenic and mutagenic properties. Multi-dimensional chromatographic techniques which provide separation by virtue of chemical class (group-type) or by molecular mass greatly simplifies the analysis of inherently complex fuel materials. In this study, on-line LC-GC techniques in which high resolution gas chromatography (HPLC) have been investigated. Comprehensive characterisation of fuel feedstocks and post-pyrolysis and combustion products was achieved by coupling LC-GC to low resolution ion trap mass spectrometry (ITD-MS) and atomic emission detection (AED). The identification of PAC in diesel and coal materials, as well as urban air and diesel exhaust particulate extracts has provided valuable insight into the source, formation and distribution of such compounds pre- and post processing.

  9. Toxicity of eight polycyclic aromatic compounds to red clover (Trifolium pratense), ryegrass (Lolium perenne), and mustard (Sinapsis alba).

    PubMed

    Sverdrup, Line E; Krogh, Paul Henning; Nielsen, Torben; Kjaer, Christian; Stenersen, Jørgen

    2003-12-01

    The effect of eight polycyclic aromatic compounds (PACs) on the seed emergence and early life-stage growth of three terrestrial plants (Sinapsis alba, Trifolium pratense and Lolium perenne) were studied in a greenhouse, using a Danish agricultural soil with an organic carbon content of 1.6%. After three weeks of exposure, seed emergence and seedling weight (fresh weight and dry weight) were determined. Exposure concentrations were verified with chemical analysis. The substances tested were four polycyclic aromatic hydrocarbons (fluoranthene, pyrene, phenanthrene and fluorene), the N-, S-, and O-substituted analogues of fluorene (carbazole, dibenzothiophene and dibenzofuran, respectively), and the quinoline representative acridine. Seedling growth was a far more sensitive endpoint than seed emergence for all substances. Concentrations estimated to give a 20% reduction of seedling fresh weight (EC20-values) ranged from 36 to 290 mgkg(-1) for carbazole, 43 to 93 mgkg(-1) for dibenzofuran, 37 to 110 mgkg(-1) for dibenzothiophene, 140 to 650 mgkg(-1) for fluoranthene, 55 to 380 mgkg(-1) for fluorene, 37 to 300 mgkg(-1) for phenanthrene, and 49 to 1300 mgkg(-1) for pyrene. For acridine, no toxicity was observed within the concentration range tested (1-1000 mgkg(-1)). As illustrated by the EC20-values, there was a rather large difference in sensitivity between the species, and T. pratense was the most sensitive of the species tested.

  10. Laboratory Studies of Organic Compounds With Reflectance Spectroscopy

    NASA Astrophysics Data System (ADS)

    Curchin, J. M.; Clark, R. N.; Hoefen, T. M.

    2007-12-01

    In order to properly interpret reflectance spectra of any solar system surface from the earth to the Oort cloud, laboratory spectra of candidate materials for comparative analysis are needed. Although the common cosmochemical species (H2O, CO2, CO, NH3, and CH4) are well represented in the spectroscopic literature, comparatively little reflectance work has been done on organics from room to cryogenic temperatures at visible to near infrared wavelengths. Reflectance spectra not only enhance weak or unseen transmission features, they are also more analogous to spectra obtained by spacecraft that are imaging such bodies as giant planet moons, kuiper belt objects, centaurs, comets and asteroids, as well as remote sensing of the earth. The USGS Spectroscopy Laboratory is measuring reflectance spectra of organic compounds from room to cryogenic temperatures over the spectral range of 0.35 to 15.5 microns. This region encompasses the fundamental absorptions and many overtones and combinations of C, H, O, and N molecular bonds. Because most organic compounds belong to families whose members have similar structure and composition, individual species identification within a narrow wavelength range may be ambiguous. By measuring spectral reflectance of the pure laboratory samples from the visible through the near and mid-infrared, absorption bands unique to each can be observed, cataloged, and compared to planetary reflectance data. We present here spectra of organic compounds belonging to five families: the alkanes, alkenes, alkynes, aromatics, and cyanides. Common to all of these are the deep C-H stretch fundamental absorptions, which shift shortward from 3.35+ microns in alkanes to 3.25+ microns in aromatics, to 3.2+ microns in alkenes, and down to 3.0+ microns in alkynes. Mid-IR absorptions due to C-H bending deformations at 6.8+ and 7.2+ microns are also identified. In the near infrared these stretching and bending fundamentals yield a diagnostic set of combination

  11. Phase equilibria in ionic liquid-aromatic compound mixtures, including benzene fluorination effects.

    PubMed

    Blesic, Marijana; Lopes, José N Canongia; Pádua, Agílio A H; Shimizu, Karina; Gomes, Margarida F Costa; Rebelo, Luís Paulo N

    2009-05-28

    This work extends the scope of previous studies on the phase behavior of mixtures of ionic liquids with benzenes or its derivatives by determining the solid-liquid and liquid-liquid phase diagrams of mixtures containing an ionic liquid and a fluorinated benzene. The systems studied include 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide plus hexafluorobenzene or 1,3,5-trifluorobenzene and 1-ethyl-3-methylimidazolium triflate or N-ethyl-N-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide plus benzene. The phase diagrams exhibit different kinds of solid-liquid behavior: the (usual) occurrence of eutectic points; the (not-so-usual) presence of congruent melting points and the corresponding formation of inclusion crystals; or the observation of different ionic liquid crystalline phases (polymorphism). These different types of behavior can be controlled by temperature annealing during crystallization or by the nature of the aromatic compound and can be interpreted, at a molecular level, taking into account the structure of the crystals or liquid mixtures, together with the unique characteristics of ionic liquids, namely the dual nature of their interactions with aromatic compounds.

  12. Volatile organic compounds from leaves litter.

    PubMed

    Isidorov, Valery; Jdanova, Maria

    2002-09-01

    Qualitative composition of volatile emissions of litter of five species of deciduous trees was investigated by GC-MS. The list of identified substances contains more than 70 organic compounds of various classes. It was established that the composition of components emitted by the litter into the gas phase greatly differs from that of essential oils extracted by hydrodistillation from turned leaves collected from trees during fall. It is suggested that most compounds found in litter emissions are products of vital activity of microorganisms decomposing it. The reported data indicate that after the vegetative period is over the decomposition processes of litter are important seasonal sources of reactive organic compounds under the forest canopy.

  13. Refractory Organic Compounds in Enceladus' Ice Grains and Hydrothermal Activity

    NASA Astrophysics Data System (ADS)

    Postberg, F.; Khawaja, N.; Hsu, H. W.; Sekine, Y.; Shibuya, T.

    2015-12-01

    Cassini's Cosmic Dust Analyzer (CDA) generates time-of-flight mass spectra of individual grains impinging on the instruments target-plate. Following the analysis of salt rich ice grains emitted by Enceladus that indicated a salt-water ocean in contact with the moon's rocky core [1,2] a recent CDA analysis of nano-phase silica particles pointed at hydrothermal activity at the moon's rock/water interface [3]. The results imply temperatures above 80 - 90°C and alkaline pH values around 10 reminiscent of alkaline hydrothermal vents on Earth like the Lost City Hydrothermal Field. In this context the compositional analysis of organic components in CDA mass spectra of the ejected ice grains is of particular relevance. A multitude of volatile organic species has already been identified in the gas component of the plume [4]. As expected, we find more complex organic molecules in ice grains than in the gas indicating aromatic species, amines, and carbonyl group species. The composition of organic-bearing ice grains displays a great diversity indicating a variety of different organic species in varying concentrations. Recent spatially resolved CDA in situ measurements inside Enceladus' plume indicate that these organic compounds are especially frequent in 'young' ice grains that have just been ejected by high velocity jets. We investigate the implications of our findings with respect to ice grain formation at the water surface and inside the icy vents. We constrain the generation of organic compounds at the rock/water interface in the light of hydrothermal activity and the potential for the formation of life precursor molecules in Enceladus' ocean. Ref:[1] Postberg et al., Nature 459, 1098-1101 (2009). [2] Postberg et al., Nature 474, 620-622 (2011). [3]. Hsu, Postberg, Sekine et al., Nature, 519, 207-210 (2015). [4] Waite et al., Nature 460, 487-490 (2009).

  14. Catalytic Destruction Of Toxic Organic Compounds

    NASA Technical Reports Server (NTRS)

    Voecks, Gerald E.

    1990-01-01

    Proposed process disposes of toxic organic compounds in contaminated soil or carbon beds safely and efficiently. Oxidizes toxic materials without producing such other contaminants as nitrogen oxides. Using air, fuel, catalysts, and steam, system consumes less fuel and energy than decontamination processes currently in use. Similar process regenerates carbon beds used in water-treatment plants.

  15. Azodicarboxylates: synthesis and functionalization of organic compounds

    NASA Astrophysics Data System (ADS)

    Zhirov, A. M.; Aksenov, A. V.

    2014-06-01

    The data on transformations of dialkyl azodicarboxylates and their analogues involving various substrates are generalized. Nucleophilic addition and oxidation, pericyclic reactions and reactions occurring under the Mitsunobu reaction conditions are considered. Ample opportunities for application of these compounds in fine organic synthesis are shown. The bibliography includes 245 references. Dedicated to Academician B A Trofimov on the occasion of his 75th birthday.

  16. Nonvolatile organic compounds in treated waters.

    PubMed Central

    Watts, C D; Crathorne, B; Fielding, M; Killops, S D

    1982-01-01

    Over the past decade much information has been published on the analysis of organics extracted from treated water. Certain of these organics have been shown to be by-products of the chlorination disinfection process and to possess harmful effects at high concentrations. This has resulted in increased interest in alternative disinfection processes, particularly ozonation. The data on organics had been largely obtained by using gas chromatography-mass spectrometry, which is only capable of analyzing, at best, 20% of the organics present in treated water. Research in key areas such as mutagenicity testing of water and characterization of chlorination and ozonation by-products has emphasized the need for techniques suitable for analysis of the remaining nonvolatile organics. Several methods for the isolation of nonvolatile organics have been evaluated and, of these, freeze-drying followed by methanol extraction appears the most suitable. Reverse-phase HPLC was used for separation of the methanol extract, but increased resolution for separation of the complex mixtures present is desirable. In this context, high resolution size exclusion chromatography shows promise. Characterization of separated nonvolatiles is possible by the application of state-of-the-art mass spectrometric techniques. Results obtained by these techniques have shown that the nonvolatile organic fraction of chlorinated drinking water consists of many discrete compounds. Among these, some of the chlorinated compounds are almost certainly by-products of disinfection. Studies of the by-products of ozonation of fulvic and humic acids isolated from river waters have indicated a similar proportion of nonvolatile organics. Further, ozonation can result in the release of compounds that are trapped in the macromolecules. PMID:6759110

  17. Anti-prion activity of a panel of aromatic chemical compounds: in vitro and in silico approaches.

    PubMed

    Ferreira, Natalia C; Marques, Icaro A; Conceição, Wesley A; Macedo, Bruno; Machado, Clarice S; Mascarello, Alessandra; Chiaradia-Delatorre, Louise Domeneghini; Yunes, Rosendo Augusto; Nunes, Ricardo José; Hughson, Andrew G; Raymond, Lynne D; Pascutti, Pedro G; Caughey, Byron; Cordeiro, Yraima

    2014-01-01

    The prion protein (PrP) is implicated in the Transmissible Spongiform Encephalopathies (TSEs), which comprise a group of fatal neurodegenerative diseases affecting humans and other mammals. Conversion of cellular PrP (PrP(C)) into the scrapie form (PrP(Sc)) is the hallmark of TSEs. Once formed, PrP(Sc) aggregates and catalyzes PrP(C) misfolding into new PrP(Sc) molecules. Although many compounds have been shown to inhibit the conversion process, so far there is no effective therapy for TSEs. Besides, most of the previously evaluated compounds failed in vivo due to poor pharmacokinetic profiles. In this work we propose a combined in vitro/in silico approach to screen for active anti-prion compounds presenting acceptable drugability and pharmacokinetic parameters. A diverse panel of aromatic compounds was screened in neuroblastoma cells persistently infected with PrP(Sc) (ScN2a) for their ability to inhibit PK-resistant PrP (PrP(Res)) accumulation. From ∼200 compounds, 47 were effective in decreasing the accumulation of PrP(Res) in ScN2a cells. Pharmacokinetic and physicochemical properties were predicted in silico, allowing us to obtain estimates of relative blood brain barrier permeation and mutagenicity. MTT reduction assays showed that most of the active compounds were non cytotoxic. Compounds that cleared PrP(Res) from ScN2a cells, were non-toxic in the MTT assay, and presented a good pharmacokinetic profile were investigated for their ability to inhibit aggregation of an amyloidogenic PrP peptide fragment (PrP(109-149)). Molecular docking results provided structural models and binding affinities for the interaction between PrP and the most promising compounds. In summary, using this combined in vitro/in silico approach we have identified new small organic anti-scrapie compounds that decrease the accumulation of PrP(Res) in ScN2a cells, inhibit the aggregation of a PrP peptide, and possess pharmacokinetic characteristics that support their drugability. These

  18. Anti-Prion Activity of a Panel of Aromatic Chemical Compounds: In Vitro and In Silico Approaches

    PubMed Central

    Ferreira, Natalia C.; Marques, Icaro A.; Conceição, Wesley A.; Macedo, Bruno; Machado, Clarice S.; Mascarello, Alessandra; Chiaradia-Delatorre, Louise Domeneghini; Yunes, Rosendo Augusto; Nunes, Ricardo José; Hughson, Andrew G.; Raymond, Lynne D.; Pascutti, Pedro G.; Caughey, Byron; Cordeiro, Yraima

    2014-01-01

    The prion protein (PrP) is implicated in the Transmissible Spongiform Encephalopathies (TSEs), which comprise a group of fatal neurodegenerative diseases affecting humans and other mammals. Conversion of cellular PrP (PrPC) into the scrapie form (PrPSc) is the hallmark of TSEs. Once formed, PrPSc aggregates and catalyzes PrPC misfolding into new PrPSc molecules. Although many compounds have been shown to inhibit the conversion process, so far there is no effective therapy for TSEs. Besides, most of the previously evaluated compounds failed in vivo due to poor pharmacokinetic profiles. In this work we propose a combined in vitro/in silico approach to screen for active anti-prion compounds presenting acceptable drugability and pharmacokinetic parameters. A diverse panel of aromatic compounds was screened in neuroblastoma cells persistently infected with PrPSc (ScN2a) for their ability to inhibit PK-resistant PrP (PrPRes) accumulation. From ∼200 compounds, 47 were effective in decreasing the accumulation of PrPRes in ScN2a cells. Pharmacokinetic and physicochemical properties were predicted in silico, allowing us to obtain estimates of relative blood brain barrier permeation and mutagenicity. MTT reduction assays showed that most of the active compounds were non cytotoxic. Compounds that cleared PrPRes from ScN2a cells, were non-toxic in the MTT assay, and presented a good pharmacokinetic profile were investigated for their ability to inhibit aggregation of an amyloidogenic PrP peptide fragment (PrP109–149). Molecular docking results provided structural models and binding affinities for the interaction between PrP and the most promising compounds. In summary, using this combined in vitro/in silico approach we have identified new small organic anti-scrapie compounds that decrease the accumulation of PrPRes in ScN2a cells, inhibit the aggregation of a PrP peptide, and possess pharmacokinetic characteristics that support their drugability. These compounds are

  19. Organic photosensitive devices using subphthalocyanine compounds

    SciTech Connect

    Rand, Barry; Forrest, Stephen R.; Mutolo, Kristin L.; Mayo, Elizabeth; Thompson, Mark E.

    2011-07-05

    An organic photosensitive optoelectronic device, having a donor-acceptor heterojunction of a donor-like material and an acceptor-like material and methods of making such devices is provided. At least one of the donor-like material and the acceptor-like material includes a subphthalocyanine, a subporphyrin, and/or a subporphyrazine compound; and/or the device optionally has at least one of a blocking layer or a charge transport layer, where the blocking layer and/or the charge transport layer includes a subphthalocyanine, a subporphyrin, and/or a subporphyrazine compound.

  20. Climate impacts of biogenic organic compounds

    NASA Astrophysics Data System (ADS)

    Sengupta, Kamalika; Gordon, Hamish; Almeida, Joao; Rap, Alex; Scott, Catherine; Pringle, Kirsty; Carslaw, Ken

    2016-04-01

    Currently the most uncertain driver of climate change, impact of anthropogenic aerosols on earth's radiative balance depends significantly on estimates of cloud condensation nuclei (CCN), representation of the pre-industrial atmosphere among others. Nearly 90% of aerosols in the tropics are organic in nature of which a major part comes from biogenic sources. About 45% of the CCN in the atmosphere are formed in-situ via nucleation. Understanding the role of biogenic organic compounds in particle formation and their subsequent growth is hence imperative in order to quantify the climate impact of aerosols. The CLOUD experiment at CERN, which measures particle formation and growth rates in a uniquely clean chamber under atmospherically relevant conditions, found evidence of a nucleation mechanism involving only biogenic organic compounds. This mechanism significantly changes our pre-industrial estimates. The experimental results have been parameterized and included in a global aerosol microphysics model, GLOMAP, to quantify the impact of pure biogenic nucleation on CCN formation and their climatic impact. Further the treatment of secondary organic compounds in GLOMAP has been improved and the sensitivity of our estimates of radiative forcing to the same has been evaluated.

  1. Biodegradation of organic compounds sequestered in organic solids or in nanopores within silica particles

    SciTech Connect

    Hatzinger, P.B.; Alexander, M.

    1997-11-01

    A study was conducted using model solids to determine whether the time-dependent decline in availability for biodegradation of organic pollutants in soil might result from the entrapment of these compounds in porous or nonporous solids. A strain of Pseudomonas mineralized phenanthrene in solid alkanes containing 18 to 32 carbons, three waxes, and low-molecular-weight polycaprolactone, polyethylene, and polypropylene. The rates were appreciably slower than when the substrate was not initially present within these nonporous solids. From 1.4 to 63.4% of the polycyclic aromatic hydrocarbon added to the solids was mineralized in 90 d. The rates and extents of partitioning of phenanthrene varied markedly among the solids. The rates of partitioning and biodegradation of phenanthrene initially present in the alkanes were positively correlated. The bacterium rapidly and extensively mineralized phenanthrene provided in calcium alginate beads containing varying amounts of soluble soil organic matter. The rates and extents of phenanthrene mineralization declined as the percentage of the substrate in the nanopores within silica particles increased, but the reductions in rate, extent, or both were less pronounced than with nonporous solids. The rate of 4-nitrophenol biodegradation also declined with increasing percentages of the compound in these nanopores. The data are consistent with hypotheses that the sequestration and consequent decrease in bioavailability of organic compounds that persist in soil result from their partitioning into organic matter or their presence within nanopores in soil.

  2. The Effects of Molecular Properties on Ready Biodegradation of Aromatic Compounds in the OECD 301B CO2 Evolution Test.

    PubMed

    He, Mei; Mei, Cheng-Fang; Sun, Guo-Ping; Li, Hai-Bei; Liu, Lei; Xu, Mei-Ying

    2016-07-01

    Ready biodegradation is the primary biodegradability of a compound, which is used for discriminating whether a compound could be rapidly and readily biodegraded in the natural ecosystems in a short period and has been applied extensively in the environmental risk assessment of many chemicals. In this study, the effects of 24 molecular properties (including 2 physicochemical parameters, 10 geometrical parameters, 6 topological parameters, and 6 electronic parameters) on the ready biodegradation of 24 kinds of synthetic aromatic compounds were investigated using the OECD 301B CO2 Evolution test. The relationship between molecular properties and ready biodegradation of these aromatic compounds varied with molecular properties. A significant inverse correlation was found for the topological parameter TD, five geometrical parameters (Rad, CAA, CMA, CSEV, and N c), and the physicochemical parameter K ow, and a positive correlation for two topological parameters TC and TVC, whereas no significant correlation was observed for any of the electronic parameters. Based on the correlations between molecular properties and ready biodegradation of these aromatic compounds, the importance of molecular properties was demonstrated as follows: geometrical properties > topological properties > physicochemical properties > electronic properties. Our study first demonstrated the effects of molecular properties on ready biodegradation by a number of experiment data under the same experimental conditions, which should be taken into account to better guide the ready biodegradation tests and understand the mechanisms of the ready biodegradation of aromatic compounds.

  3. Ambient cure polyimide foams prepared from aromatic polyisocyanates, aromatic polycarboxylic compounds, furfuryl alcohol, and a strong inorganic acid

    NASA Technical Reports Server (NTRS)

    Sawko, Paul M. (Inventor); Riccitiello, Salvatore R. (Inventor); Hamermesh, Charles L. (Inventor)

    1980-01-01

    Flame and temperature resistant polyimide foams are prepared by the reaction of an aromatic dianhydride, e.g., pyromellitic dianhydride, with an aromatic polyisocyanate, e.g., polymethylene polyphenylisocyanate (PAPI) in the presence of an inorganic acid and a lower molecular weight alcohol, e.g., dilute sulfuric acid or phosphoric acid and furfuryl alcohol. The exothermic reaction between the acid and the alcohol provides the heat necessary for the other reactants to polymerize without the application of any external heat. Such mixtures, therefore, are ideally suited for in situ foam formation, especially where the application of heat is not practical or possible.

  4. Organic compounds leached from fast pyrolysis mallee leaf and bark biochars.

    PubMed

    Lievens, Caroline; Mourant, Daniel; Gunawan, Richard; Hu, Xun; Wang, Yi

    2015-11-01

    Characterization of organic compounds leached from biochars is essential in assessing the possible toxicity of the biochar to the soils' biota. In this study the nature of the leached organic compounds from Mallee biochars, produced from pyrolysis of Mallee leaf and bark in a fluidised-bed pyrolyser at 400 and 580°C was investigated. Light bio-oil compounds and aromatic organic compounds were investigated. The 'bio-oil like' light compounds from leaf and bark biochars 'surfaces were obtained after leaching the chars with a solvent, suitable to dissolve the respective bio-oils. GC/MS was implemented to investigate the leachates. Phenolics, which are potentially harmful toxins, were detected and their concentration shown to be dependent on the char's origin and the char production temperature. Further, to simulate biochars amendment to soils, the chars were leached with water. The water-leached aromatic compounds from leaf and bark biochars were characterized using UV-fluorescence spectroscopy. Those results suggested that biochars contain leachable compounds of which the nature and amount is dependent on the biomass feedstock, pyrolysis temperature and leaching time.

  5. Identification and quantification of volatile organic compounds from a dairy

    NASA Astrophysics Data System (ADS)

    Filipy, Jenny; Rumburg, Brian; Mount, George; Westberg, Hal; Lamb, Brian

    Volatile organic compounds (VOCs) that contribute to odor and air quality problems have been identified from the Washington State University Knott Dairy Farm using gas chromatography-mass spectroscopy (GC-MS). Eighty-two VOCs were identified at a lactating cow open stall and 73 were detected from a slurry wastewater lagoon. These compounds included alcohols, aldehydes, ketones, esters, ethers, aromatic hydrocarbons, halogenated hydrocarbons, terpenes, other hydrocarbons, amines, other nitrogen containing compounds, and sulfur-containing compounds. The concentration of VOCs directly associated with cattle waste increased with ambient air temperature, with the highest concentrations present during the summer months. Concentrations of most detected compounds were below published odor detection thresholds. Emission rates of ethanol (1026±513 μg cow -1 s -1) and dimethyl sulfide (DMS) (13.8±10.3 μg cow -1 s -1) were measured from the lactating stall area using an atmospheric tracer method and concentrations were plotted using data over a 2-year period. Emission rates of acetone (3.03±0.85 ng cow -1 s -1), 2-butanone (145±35 ng cow -1 s -1), methyl isobutyl ketone (3.46±1.11 ng cow -1 s -1), 2-methyl-3-pentanone (25.1±8.0 ng cow -1 s -1), DMS (2.19±0.92 ng cow -1 s -1), and dimethyl disulfide (DMDS) (16.1±3.9 ng cow -1 s -1) were measured from the slurry waste lagoon using a laboratory emission chamber.

  6. Predicting the octanol solubility of organic compounds.

    PubMed

    Admire, Brittany; Yalkowsky, Samuel H

    2013-07-01

    The molar octanol solubility of an organic nonelectrolytes can be reasonably predicted solely from its melting point provided that its liquid (or a hypothetical super-cooled liquid) form is miscible with octanol. The aim of this work is to develop criteria to determine if the real or hypothetical liquid form of a given compound will be miscible with octanol based on its molar volume and solubility parameter. Fortunately, most organic compounds (including most drugs) conform to the criteria for complete liquid miscibility, and therefore have solubilities that are proportional to their melting points. The results show that more than 95% of the octanol solubilities studied are predicted with an error of less than 1 logarithmic unit.

  7. Enumeration of human colonic bacteria producing phenolic and indolic compounds: effects of pH, carbohydrate availability and retention time on dissimilatory aromatic amino acid metabolism.

    PubMed

    Smith, E A; Macfarlane, G T

    1996-09-01

    Concentrations of phenolic compounds in human gut contents were more than fourfold higher in the distal colon (6.2 mmol kg-1) compared to the proximal bowel (1.4 mmol kg-1). Tryptophan metabolites were never found in more than trace amounts in large intestinal contents and phenol substituted fatty acids were the major products of aromatic amino acid fermentation that accumulated in the proximal colon, whereas phenol and p-cresol were more important in the distal gut, accounting for 70% of all products of dissimilatory aromatic amino acid metabolism. In vitro incubations of colonic material showed that phenol was produced most rapidly (1.0 mumol g-1 h-1), whereas indole was formed comparatively slowly (0.06 mumol g-1 h-1). Most probable number (MPN) estimations demonstrated that large populations of phenol and indole producing bacteria occur in the large intestine (range log10 9.8-11.5 (g dry wt faeces)-1, mean 10.6, N = 7). With respect to phenolic compounds, phenylacetate and phenylpropionate producers predominated, while indoleacetate-forming bacteria were the major tryptophan-utilizing organisms. Quantitation of products of dissimilatory aromatic amino acid metabolism in MPN tubes showed that phenol and phenylpropionate mainly accumulated at low sample dilutions, whereas phenylacetate, p-cresol, indoleacetate and indolepropionate were formed in greatest amounts at high sample dilutions. The significance of pH and carbohydrate availability with respect to aromatic amino acid metabolism was shown in batch culture fermentation studies, where net production of phenolic compounds by mixed populations of intestinal bacteria was reduced by approximately 33% during growth at pH 5.5 compared to pH 6.8, and by 60% in the presence of a fermentable carbohydrate. Experiments with 16 species of intestinal bacteria belonging to six different genera showed that environmental factors such as low pH and high carbohydrate availability markedly reduced dissimilatory aromatic amino

  8. How aromatic compounds block DNA binding of HcaR catabolite regulator

    DOE PAGES

    Kim, Youngchang; Joachimiak, Grazyna; Bigelow, Lance; ...

    2016-04-25

    Bacterial catabolism of aromatic compounds from various sources including phenylpropanoids and flavonoids that are abundant in soil plays an important role in the recycling of carbon in the ecosystem. We have determined the crystal structures of apo-HcaR from Acinetobacter sp. ADP1, a MarR/SlyA transcription factor, in complexes with hydroxycinnamates and a specific DNA operator. The protein regulates the expression of the hca catabolic operon in Acinetobacter and related bacterial strains, allowing utilization of hydroxycinnamates as sole sources of carbon. HcaR binds multiple ligands, and as a result the transcription of genes encoding several catabolic enzymes is increased. The 1.9-2.4 Åmore » resolution structures presented here explain how HcaR recognizes four ligands (ferulate, 3,4-dihydroxybenzoate, p-coumarate, and vanillin) using the same binding site. The ligand promiscuity appears to be an adaptation to match a broad specificity of hydroxycinnamate catabolic enzymes while responding to toxic thioester intermediates. Structures of apo-HcaR and in complex with a specific DNA hca operator when combined with binding studies of hydroxycinnamates show how aromatic ligands render HcaR unproductive in recognizing a specific DNA target. Furthermore, the current study contributes to a better understanding of the hca catabolic operon regulation mechanism by the transcription factor HcaR.« less

  9. How aromatic compounds block DNA binding of HcaR catabolite regulator

    SciTech Connect

    Kim, Youngchang; Joachimiak, Grazyna; Bigelow, Lance; Babnigg, Gyorgy; Joachimiak, Andrzej

    2016-04-25

    Bacterial catabolism of aromatic compounds from various sources including phenylpropanoids and flavonoids that are abundant in soil plays an important role in the recycling of carbon in the ecosystem. We have determined the crystal structures of apo-HcaR from Acinetobacter sp. ADP1, a MarR/SlyA transcription factor, in complexes with hydroxycinnamates and a specific DNA operator. The protein regulates the expression of the hca catabolic operon in Acinetobacter and related bacterial strains, allowing utilization of hydroxycinnamates as sole sources of carbon. HcaR binds multiple ligands, and as a result the transcription of genes encoding several catabolic enzymes is increased. The 1.9-2.4 Å resolution structures presented here explain how HcaR recognizes four ligands (ferulate, 3,4-dihydroxybenzoate, p-coumarate, and vanillin) using the same binding site. The ligand promiscuity appears to be an adaptation to match a broad specificity of hydroxycinnamate catabolic enzymes while responding to toxic thioester intermediates. Structures of apo-HcaR and in complex with a specific DNA hca operator when combined with binding studies of hydroxycinnamates show how aromatic ligands render HcaR unproductive in recognizing a specific DNA target. Furthermore, the current study contributes to a better understanding of the hca catabolic operon regulation mechanism by the transcription factor HcaR.

  10. Enhanced Photoreduction of Nitro-aromatic Compounds by Hydrated Electrons Derived from Indole on Natural Montmorillonite.

    PubMed

    Tian, Haoting; Guo, Yong; Pan, Bo; Gu, Cheng; Li, Hui; Boyd, Stephen A

    2015-07-07

    A new photoreduction pathway for nitro-aromatic compounds (NACs) and the underlying degradation mechanism are described. 1,3-Dinitrobenzene was reduced to 3-nitroaniline by the widely distributed aromatic molecule indole; the reaction is facilitated by montmorillonite clay mineral under both simulated and natural sunlight irradiation. The novel chemical reaction is strongly affected by the type of exchangeable cation present on montmorillonite. The photoreduction reaction is initiated by the adsorption of 1,3-dinitrobenzene and indole in clay interlayers. Under light irradiation, the excited indole molecule generates a hydrated electron and the indole radical cation. The structural negative charge of montmorillonite plausibly stabilizes the radical cation hence preventing charge recombination. This promotes the release of reactive hydrated electrons for further reductive reactions. Similar results were observed for the photoreduction of nitrobenzene. In situ irradiation time-resolved electron paramagnetic resonance and Fourier transform infrared spectroscopies provided direct evidence for the generation of hydrated electrons and the indole radical cations, which supported the proposed degradation mechanism. In the photoreduction process, the role of clay mineral is to both enhance the generation of hydrated electrons and to provide a constrained reaction environment in the galley regions, which increases the probability of contact between NACs and hydrated electrons.

  11. Diffusion of aromatic compounds in nonaqueous solvents: a study of solute, solvent, and temperature dependences.

    PubMed

    Chan, T C; Tang, W K

    2013-06-14

    Tracer diffusivities (limiting mutual diffusion coefficients) of nonassociated aromatic compounds in n-hexane and cyclohexane have been measured at 298.2 K by Taylor's dispersion method. These new data, together with other diffusivities of nonassociated pseudoplanar solutes reported in the literature, are used to determine the separate effects of solute and solvent on tracer diffusion. The data show that for a given pseudoplanar solute diffusing in different solvents at 298.2 K, the tracer diffusivity is dependent not only on the fractional viscosity of the solvent but also on a function of the solvent's molar density, molecular mass, and free volume fraction. For different pseudoplanar aromatic solutes diffusing in a particular solvent at a constant temperature, there is a linear relationship between the reciprocal of the tracer diffusivity and the molecular volume of the solutes. The results are discussed in respect to relevant theories and experimental studies in the literature. An idealized relation, developed on the basis of the Einstein equation by incorporating the newly found solute and solvent dependences, is capable of describing a total of 176 diffusivities of nonassociated pseudoplanar solutes in various solvents at different temperatures to within an average error of ±2.8%.

  12. Organic Compounds in Star Forming Regions

    NASA Astrophysics Data System (ADS)

    Kochina, O.; Wiebe, D.

    2014-09-01

    The influence of complex dust composition on the general chemical evolution of a prestellar core and the content of complex organic compounds is studied. It is shown that various component groups respond differently to the presence of a small dust population. At early stages the difference is determined primarily by changes in the balance of photo processes due to effective absorption of ultraviolet photons by small dust grains of the second population and collisional reactions with dust particles. At later stages differences are also caused by the growing dominance of additional reaction channels related to surface organic synthesis.

  13. Organic compounds in star forming regions.

    PubMed

    Kochina, O; Wiebe, D

    2014-09-01

    The influence of complex dust composition on the general chemical evolution of a prestellar core and the content of complex organic compounds is studied. It is shown that various component groups respond differently to the presence of a small dust population. At early stages the difference is determined primarily by changes in the balance of photo processes due to effective absorption of ultraviolet photons by small dust grains of the second population and collisional reactions with dust particles. At later stages differences are also caused by the growing dominance of additional reaction channels related to surface organic synthesis.

  14. Metabolic Reactions among Organic Sulfur Compounds

    NASA Technical Reports Server (NTRS)

    Schulte, M.; Rogers, K.

    2005-01-01

    Sulfur is central to the metabolisms of many organisms that inhabit extreme environments. Numerous authors have addressed the energy available from a variety of inorganic sulfur redox pairs. Less attention has been paid, however, to the energy required or gained from metabolic reactions among organic sulfur compounds. Work in this area has focused on the oxidation of alkyl sulfide or disulfide to thiol and formaldehyde, e.g. (CH3)2S + H2O yields CH3SH + HCHO + H2, eventually resulting in the formation of CO2 and SO4(-2). It is also found that reactions among thiols and disulfides may help control redox disequilibria between the cytoplasm and the periplasm. Building on our earlier efforts for thiols, we have compiled and estimated thermodynamic properties for alkyl sulfides. We are investigating metabolic reactions among various sulfur compounds in a variety of extreme environments, ranging from sea floor hydrothermal systems to organic-rich sludge. Using thermodynamic data and the revised HKF equation of state, along with constraints imposed by the geochemical environments sulfur-metabolizing organisms inhabit, we are able to calculate the amount of energy available to these organisms.

  15. Supramolecular chemistry: from aromatic foldamers to solution-phase supramolecular organic frameworks

    PubMed Central

    2015-01-01

    Summary This mini-review covers the growth, education, career, and research activities of the author. In particular, the developments of various folded, helical and extended secondary structures from aromatic backbones driven by different noncovalent forces (including hydrogen bonding, donor–acceptor, solvophobicity, and dimerization of conjugated radical cations) and solution-phase supramolecular organic frameworks driven by hydrophobically initiated aromatic stacking in the cavity of cucurbit[8]uril (CB[8]) are highlighted. PMID:26664626

  16. Compositional space boundaries for organic compounds.

    PubMed

    Lobodin, Vladislav V; Marshall, Alan G; Hsu, Chang Samuel

    2012-04-03

    An upper elemental compositional boundary for fossil hydrocarbons has previously been established as double-bond equivalents (i.e., DBE = rings plus double bonds) not exceeding 90% of the number of carbons. For heteroatom-containing fossil compounds, the 90% rule still applies if each N atom is counted as a C atom. The 90% rule eliminates more than 10% of the possible elemental compositions at a given mass for fossil database molecules. However, some synthetic compounds can fall outside the upper boundary defined for naturally occurring compounds. Their inclusion defines an "absolute" upper boundary as DBE (rings plus double bonds to carbon) equal to carbon number plus one, and applies to all organic compounds including fullerenes and other molecules containing no hydrogen. Finally, the DBE definition can fail for molecules with particular atomic valences. Therefore, we also present a generalized DBE definition that includes atomic valence to enable calculation of the correct total number of rings, double bonds, and triple bonds for heteroatom-containing compounds.

  17. Synergistic and diminutive effects between halogen bond and lithium bond in complexes involving aromatic compounds.

    PubMed

    Liu, Mingxiu; Cai, Mengyang; Li, Qingzhong; Li, Wenzuo; Cheng, Jianbo

    2015-10-01

    Quantum chemical calculations have been performed to study the interplay between halogen bond and lithium bond in the ternary systems FX-C6H5CN-LiF, FLi-C6H5CN-XF, and FLi-C6H5X-NH3 (X = Cl, Br, and I) involving aromatic compounds. This effect was studied in terms of interaction energy, electron density, charge transfer, and orbital interaction. The results showed that both FX-C6H5CN-LiF and FLi-C6H5CN-XF exhibit diminutive effects with the weakening of halogen bond and lithium bond, while FLi-C6H5X-NH3 displays synergistic effects with the strengthening of halogen bond and lithium bond. The nature of halogen bond and lithium bond in the corresponding binary complexes has been unveiled by the quantum theory of atoms in molecules methodology and energy decomposition analysis.

  18. Screening of halogenated aromatic compounds in some raw material lots for an aluminium recycling plant.

    PubMed

    Sinkkonen, Seija; Paasivirta, Jaakko; Lahtiperä, Mirja; Vattulainen, Antero

    2004-05-01

    Four samples of scrap raw materials for an aluminium recycling plant were screened for the occurrence of persistent halogenated aromatic compounds. The samples contained waste from handling of electric and electronic plastics, filter dust from electronic crusher, cyclone dust from electronic crusher and light fluff from car shredder. In our screening analyses, brominated flame retardants were observed in all samples. Polybrominated diphenyl ethers (PBDE) were identified in all samples in amounts of 245-67450 ng/g. The major PBDE congeners found were decabromo- and pentabromodiphenyl ethers. 1,1-bis(2,4,6-tribromophenoxy)ethane, hexabromobenzene, ethyl-pentabromobenzene, tetrabromobisphenol-A, pentabromotoluene and dimethyl tetrabromobenzene were observed in all scrap samples. The concentrations of PCBs, PCNs (polychlorinated naphthalenes) and nona- to undecachlorinated terphenyls in some of these scrap samples were remarkably high.

  19. Determination of polycyclic aromatic compounds and dioxin receptor ligands present in diesel exhaust particulate extracts

    NASA Astrophysics Data System (ADS)

    Li, Hang; Banner, Carol D.; Mason, Grant G.; Westerholm, Roger N.; Rafter, Joseph J.

    Polycyclic aromatic compounds and dioxin receptor ligands present in diesel particulate extract fractions and subfractions were determined. A crude model diesel particulate extract was fractionated into five fractions (I-V), fractions I, II and III were further fractionated into subfractions (I-1, I-2, II-1 to II-7 and III-1 to III-6). The amounts of 33 PAC present in fraction II and its subfractions were determined by gas chromatography-mass spectrometry. The amounts of 1-nitropyrene present in fraction III and its subfractions were analysed by high performance liquid chromatography with fluorescence detection. The ability of each fraction and subfraction to compete with 2,3,7,8-tetrachloro[1,6-[ 3H

  20. Determining inhibition effects of some aromatic compounds on peroxidase enzyme purified from white and red cabbage

    NASA Astrophysics Data System (ADS)

    Öztekin, Aykut; Almaz, Züleyha; Özdemir, Hasan

    2016-04-01

    Peroxidases (E.C.1.11.1.7) catalyze the one electron oxidation of wide range of substrates. They are used in synthesis reaction, removal of peroxide from industrial wastes, clinical biochemistry and immunoassays. In this study, the white cabbage (Brassica Oleracea var. capitata f. alba) and red cabbage (Brassica oleracea L. var. capitata f. rubra) peroxidase enzymes were purified for investigation of inhibitory effect of some aromatic compounds on these enzymes. IC50 values and Ki constants were calculated for the molecules of 6-Amino nicotinic hydrazide, 6-Amino-5-bromo nicotinic hydrazide, 2-Amino-5-hydroxy benzohydrazide, 4-Amino-3-hydroxy benzohydrazide on purified enzymes and inhibition type of these molecules were determined. (This research was supported by Ataturk University. Project Number: BAP-2015/98).

  1. Simple determination of a strongly aromatic compound, sotolon, by capillary electrophoresis.

    PubMed

    Taga, Atsushi; Sato, Atsushi; Suzuki, Kentaro; Takeda, Manami; Kodama, Shuji

    2012-01-01

    A strongly aromatic compound, sotolon, was assessed by capillary zone electrophoresis within 9 min without specific pre-sample treatment. The calibration curve comprised a straight line with good linearity (R = 0.997) over a relatively wide range of 3.13 to 100 ppm. The precision of this system was excellent with relative standard deviations of 1.39% for migration time and 2.96 % for peak response over 10 repetitions at a concentration of 12.5 ppm. The limit of quantitation and limit of detection values were 3.13 ppm (S/N = 9) and 0.781 ppm (S/N = 3), respectively. Using this system, sotolon was clearly detected from a maple-flavored food additive.

  2. Evaluation of Aromatic Plants and Compounds Used to Fight Multidrug Resistant Infections

    PubMed Central

    Perumal Samy, Ramar; Manikandan, Jayapal; Al Qahtani, Mohammed

    2013-01-01

    Traditional medicine plays a vital role for primary health care in India, where it is widely practiced to treat various ailments. Among those obtained from the healers, 78 medicinal plants were scientifically evaluated for antibacterial activity. Methanol extract of plants (100 μg of residue) was tested against the multidrug resistant (MDR) Gram-negative and Gram-positive bacteria. Forty-seven plants showed strong activity against Burkholderia pseudomallei (strain TES and KHW) and Staphylococcus aureus, of which Tragia involucrata L., Citrus acida Roxb. Hook.f., and Aegle marmelos (L.) Correa ex Roxb. showed powerful inhibition of bacteria. Eighteen plants displayed only a moderate effect, while six plants failed to provide any evidence of inhibition against the tested bacteria. Purified compounds showed higher antimicrobial activity than crude extracts. The compounds showed less toxic effect to the human skin fibroblasts (HEPK) cells than their corresponding aromatic fractions. Phytochemical screening indicates that the presence of various secondary metabolites may be responsible for this activity. Most of the plant extracts contained high levels of phenolic or polyphenolic compounds and exhibited activity against MDR pathogens. In conclusion, plants are promising agents that deserve further exploration. Lead molecules available from such extracts may serve as potential antimicrobial agents for future drug development to combat diseases caused by the MDR bacterial strains as reported in this study. PMID:24223059

  3. Effect of interlayer cations of montmorillonite on the biodegradation and adsorption of crude oil polycyclic aromatic compounds.

    PubMed

    Ugochukwu, Uzochukwu C; Manning, David A C; Fialips, Claire I

    2014-09-01

    Cation exchange capacity, surface acidity and specific surface area are surface properties of clay minerals that make them act as catalysts or supports in most biogeochemical processes hence making them play important roles in environmental control. However, the role of homoionic clay minerals during the biodegradation of polycyclic aromatic compounds is not well reported. In this study, the effect of interlayer cations of montmorillonites in the removal of some crude oil polycyclic aromatic compounds during biodegradation was investigated in aqueous clay/oil microcosm experiments with a hydrocarbon degrading microorganism community. The homoionic montmorillonites were prepared via cation exchange reactions by treating the unmodified montmorillonite with the relevant metallic chloride. The study indicated that potassium-montmorillonite and zinc-montmorillonite did not enhance the biodegradation of the polycyclic aromatic hydrocarbons whereas calcium-montmorillonite, and ferric-montmorillonite enhanced their biodegradation significantly. Adsorption of polycyclic aromatic hydrocarbons was significant during biodegradation with potassium- and zinc-montmorillonite where there was about 45% removal of the polycyclic aromatic compounds by adsorption in the experimental microcosm containing 5:1 ratio (w/w) of clay to oil.

  4. An Assessment of the Stability and the Potential for In-Situ Synthesis of Regulated Organic Compounds in High Level Radioactive Waste Stored at Hanford, Richland, Washington

    SciTech Connect

    Wiemers, K.D.; Babad, H.; Hallen, R.T.; Jackson, L.P.; Lerchen, M.E.

    1999-01-04

    The stability assessment examined 269 non-detected regulated compounds, first seeking literature references of the stability of the compounds, then evaluating each compound based upon the presence of functional groups using professional judgment. Compounds that could potentially survive for significant periods in the tanks (>1 year) were designated as stable. Most of the functional groups associated with the regulated organic compounds were considered unstable under tank waste conditions. The general exceptions with respect to functional group stability are some simple substituted aromatic and polycyclic aromatic compounds that resist oxidation and the multiple substituted aliphatic and aromatic halides that hydrolyze or dehydrohalogenate slowly under tank waste conditions. One-hundred and eighty-one (181) regulated, organic compounds were determined as likely unstable in the tank waste environment.

  5. Polycyclic aromatic hydrocarbon contamination of recent sediments and marine organisms from Xiamen Bay, China.

    PubMed

    Li, Qingzhao; Zhang, Xian; Yan, Changzhou

    2010-04-01

    Surface marine sediments from 12 sites within Xiamen Bay (XMB) and marine organisms (clam, crab, and fish) from a heavily polycyclic aromatic hydrocarbon (PAH)-contaminated site at Yuandang Lagoon were sampled and analyzed for 16 priority PAH content by gas chromatography/mass spectrometry. The total PAH concentrations in sediments ranged from 203.7 to 1590.5 ng/g, with an average value of 670.0 ng/g. Overall, the total PAH concentrations were relatively lower in the east coastal zone and significantly higher in Yuandang Lagoon. These concentrations were intermediate in comparison with those observed in other estuaries in China. The sources of PAH inputs to sediments in XMB were quantitatively determined by principal components analysis with multiple linear regression. The results showed that, on average, vehicle emissions, petroleum spills, and coal combustion contributed to 41, 36, and 23% of the total PAHs, respectively. Analysis of the PAH composition pattern in marine organisms showed that the total PAHs levels of fishes were lower than those of the clam and crab. The PAH burden of the crab and calm was characterized by the non-negligible occurrence of high-molecular-weight compounds, whereas the fish PAH pattern was dominated by the lower-molecular-weight compounds. In addition, the carcinogenic PAH benzo[a]pyrene was detected in all samples. Molecular indices based on isomeric PAH ratios differentiated the uptake pathway among organisms. The water soluble matter and the petroleum seemed to be the most favorable uptake pathway in fish from Yuandang Lagoon, whereas the crab and clam shared a mix uptake by the water-soluble and the particulate matter.

  6. Measurement of aromatic compounds in automobile exhaust gases with membrane inlet mass spectrometry equipped with an on-line-probe and an automatic Tenax-Sampler

    SciTech Connect

    Matz, G.; Walte, A.; Muenchmeyer, W.; Rikeit, H.E.

    1996-09-01

    A novel membrane inlet mass spectrometer is used to monitor organic compounds in combustion emissions. Different gas probes, which can be changed in minutes, have been developed for use in combination with the mobile mass spectrometer. With the On-Line-Probe, volatile organic compounds (BTXE) can be measured down to the ppm range with a cycle rate of one analysis per second. Time resolved measurements of aromatic compounds together with other exhaust gases can be done. By sampling with a polymer adsorbent, analysis with thermal desorption and GC/MS down to the ppb concentration range can be achieved. A six-fold Tenax-Sampler, connected to the mobile GC/MS system, is capable of taking and transferring the samples automatically. Because sampling with this device is independent from the analysis, measurements of narrow time windows in a dynamical process can be done easily. The whole analytical equipment was evaluated on-site through measurements on an engine test stand, a dynamometer and on the road during real traffic. It is shown, that time resolved quantitative measurements give information on the influence of special driving conditions (warm up, congestion) on the amount of aromatic compounds emitted by automobile exhausts.

  7. The pollution characteristics of odor, volatile organochlorinated compounds and polycyclic aromatic hydrocarbons emitted from plastic waste recycling plants.

    PubMed

    Tsai, Chung-Jung; Chen, Mei-Lien; Chang, Keng-Fu; Chang, Fu-Kuei; Mao, I-Fang

    2009-02-01

    Plastic waste treatment trends toward recycling in many countries; however, the melting process in the facilities which adopt material recycling method for treating plastic waste may emit toxicants and cause sensory annoyance. The objectives of this study were to analyze the pollution characteristics of the emissions from the plastic waste recycling plants, particularly in harmful volatile organochlorinated compounds, polycyclic aromatic hydrocarbons (PAHs), odor levels and critical odorants. Ten large recycling plants were selected for analysis of odor concentration (OC), volatile organic compounds (VOCs) and PAHs inside and outside the plants using olfactometry, gas chromatography-mass spectrometry and high performance liquid chromatography-fluorescence detector, respectively. The olfactometric results showed that the melting processes used for treating polyethylene/polypropylene (PE/PP) and polyvinyl chloride (PVC) plastic waste significantly produced malodor, and the odor levels at downwind boundaries were 100-229 OC, which all exceeded Taiwan's EPA standard of 50 OC. Toluene, ethylbenzene, 4-methyl-2-pentanone, methyl methacrylate and acrolein accounted for most odors compared to numerous VOCs. Sixteen organochlorinated compounds were measured in the ambient air emitted from the PVC plastic waste recycling plant and total concentrations were 245-553 microg m(-3); most were vinyl chloride, chloroform and trichloroethylene. Concentrations of PAHs inside the PE/PP plant were 8.97-252.16 ng m(-3), in which the maximum level were 20-fold higher than the levels detected from boundaries. Most of these recycling plants simply used filter to treat the melting fumes, and this could not efficiently eliminate the gaseous compounds and malodor. Improved exhaust air pollution control were strongly recommended in these industries.

  8. The Aromatic Carotenoids in the Organic Matter of the Devonian Domanic Formation (on example of Tatarstan territory)

    NASA Astrophysics Data System (ADS)

    Plotnikova, Irina; Nosova, Fidania; Ostroukhov, Sergey; Pronin, Nikita

    2015-04-01

    This report contains the results of the studies of shale hydrocarbons (HC) from carbonate-siliceous rocks on the territory of Melekess depressoin and South-Tatar arch of Volga-Ural oil and gas province of the East European Platform. Studies were performed in the laboratory of Geochemistry of Combustible Minerals at the Institute of Geology and Petroleum Technology of the Kazan Federal University. The main object of this study is Domanicoid high-TOC rocks of Devonian time. They are mainly represented by dark gray, almost black bituminous limestones that are interbedded with calcareous siliceous shales and cherts. Complex studies include the following: - extraction of bitumen from the rock, - determination of organic carbon content, - determination of the group and elemental composition of the bitumen, - gas chromatographic studies of the alkanoic lube fractions of bitumoid and oil, - gas chromato-mass spectrometry of the naphthenic lube fractions of bitumoid and oil, - isotopic studies of bitumens and oils, - pyrolysis studies of the rock using the Rock -Eval method (before and after extraction), - study of trace-element composition of the rocks and petrologen, comparison in terms of adsorbed gas and studying of the composition of adsorbed gases. Simultaneously with the study of standard and generally accepted biomarkers, deep and detailed study of alkyl toluene, aromatic hydrocarbons (and aromatic carotenoids in particular) were conducted. The comparison and comparative correlation aromatic carotenoids with standard biomarkers (for example, with hopanes C30 and steranes C27:C28:C29). Attitude hopane/aromatic carotenoids is 0.05. This testifies to the dominance of the transformation of carotenoid compounds on bacterial activity in the water column. Bacterial activity in the studied samples is also high. Attitude steranes C29/aromatic carotenoids reaches 10-3. The study of aromatic carotenoids has allowed first in the region of Tatarstan to get a new information on

  9. Relating desorption of polycyclic aromatic hydrocarbons from harbour sludges to type of organic material

    NASA Astrophysics Data System (ADS)

    Heister, K.; Pols, S.; Loch, J. P. G.; Bosma, T.

    2009-04-01

    For decades, polycyclic aromatic hydrocarbons (PAH) cause great concern as environmental pollutants. Especially river and marine harbour sediments are frequently polluted with PAH derived from surface runoff, fuel and oil spills due to shipping and industrial activities, industrial waste and atmospheric deposition. Harbour sediments contain large amounts of organic carbon and clay minerals and are therefore not easy to remediate and have to be stored in sludge depositories after dredging to maintain sufficient water depth for shipping. The organic contaminants will be adsorbed to particles, leached in association with dissolved organic material or microbially degraded. However, compounds of high molecular weight are very persistent, particularly under anaerobic conditions, thus giving rise to the potential to become desorbed again. PAH adsorb mainly to organic material. It has been shown that components of the organic material with a low polarity and a high hydrophobicity like aliphatic and aromatic components exhibit a high sorption capacity for hydrophobic organic contaminants like PAH. Accordingly, not only the amount but also the type of organic material needs to be determined in order to be able to predict contaminant behaviour. In this study, desorption behaviour of the 16 EPA-PAH in two different harbour sludges from the port of Rotterdam, the Netherlands, has been investigated. The Beerkanaal (BK) site is located relatively close to the North Sea and represents a brackish environment; the Beneden Merwede River (BMR) site originates from a fresh water environment and is close to industrial sites. The samples were placed in dialysis membranes and brought into contact with water for a period of 130 days. At several time intervals, water samples were retrieved for analysis of pH, dissolved organic carbon (DOC) content, electrical conductivity and PAH concentrations. The experiment was conducted at 4 and at 20°C. Although the samples were initially treated with

  10. Soft X-ray absorption spectra in the 0 K region of microporous carbon and some reference aromatic compounds

    SciTech Connect

    Muramatsu, Yasuji; Kuramoto, Kentaro; Gullikson, Eric M.; Perera, Rupert C.C.

    2003-06-01

    To analyze the oxidation states of the graphitic surface of microporous carbon, soft X-ray absorption spectra in the 0 K region have been obtained for microporous carbon and various aromatic compounds. The aromatic molecules studied are substituted with one or more of the following oxygenated functional groups: hydroxy (-OH), carboxy (-COOH), carbonyl (>C=O), formyl (-CH=O), and ether (-O-). From comparison of the soft X-ray absorption spectra of microporous carbon and of reference aromatic compounds, the most probable chemical bonding states of oxygen in microporous carbon are found to be -COOH and >C(H)=O. Spectral features in the soft X-ray absorption spectra of microporous carbon are well explained by the O2p density of states in these oxygenated functional groups from discrete variational (DV)-X{alpha} molecular orbital calculations.

  11. Seeking organic compounds on Mars : in situ analysis of organic compounds by Gas Chromatography-Mass Spectrometry on MOMA experiment

    NASA Astrophysics Data System (ADS)

    Buch, A.; Freissinet, C.; Sternberg, R.; Pinnick, V.; Szopa, C.; Coll, P. J.; Rodier, C.; Garnier, C.; Steininger, H.; Moma Team

    2010-12-01

    The search for signs of past or present life is one of the primary goals of future Mars exploratory missions. The Mars Organic Molecule Analyzer (MOMA) experiment of the ExoMars mission (set to launch 2016-2018) is a joint venture by the European Space Agency and NASA to develop a sensitive detector for organics on Mars. MOMA will be one of the main analytical instruments aboard the ExoMars Rover aimed at characterizing possible “signs-of-life molecules” in the Martian environment such as amino acids, carboxylic acids, nucleobases or polycyclic aromatic hydrocarbons (PAHs). With the aim to separate and detect organic compounds from Martian soil, the French MOMA team has built a gas chromatograph able to work in standalone mode by using a TCD detector. The gas chromatograph can also be coupled with an ion trap mass spectrometer developed by the US MOMA team. Moreover, a GC-MS compatible sample processing system (SPS) allowing the extraction and the chemical transformation of the organic compounds from the soil, that fits within space flight conditions, has also been developed. The sample processing is performed in an oven, dedicated to the MOMA experiment containing the solid sample (50-100mg). The internal temperature of oven can be ranged from 20 to 1000 °C which allows for pyrolysis, thermochemolysis or derivatization. The organic extraction step is achieved by using thermodesorption in the range of 100 to 300°C for 0.5 to 5 min. Then, the chemical derivatization and/or thermochemolysis of the extracted compounds is performed directly on the soil with a mixture of MTBSTFA-DMF, TMAH or DMF-DMA solution when enantiomeric separation is required. By decreasing the polarity of the target molecules, this step allows for their volatilization at a temperature below 250°C without any chemical degradation. Once derivatized, the volatile target molecules are trapped in a cold chemical trap and promptly desorbed into the gas chromatograph coupled to the mass

  12. Organic composition of atmospheric urban aerosol: Variations and sources of aliphatic and polycyclic aromatic hydrocarbons

    NASA Astrophysics Data System (ADS)

    Mazquiarán, Miguel A. Barrero; Cantón Ortiz de Pinedo, Lourdes

    2007-09-01

    The non-polar organic composition of airborne particulate matter was analysed over a two year period in an urban area under oceanic climate conditions (Errenteria, Basque Country, Spain). In addition, the distribution of polycyclic aromatic hydrocarbons (PAH) among different aerosol particle sizes was determined. Clues as to the origin of various particle types were gained by using scanning electron microscopy to view the morphology of the particulates in each size fraction. Samples were collected on glass fibre filters and analysed by means of soxhlet extraction and gas chromatography (either with a flame ionization detector or coupled to a mass spectrometry). In general, total PAH levels were moderate (0.96-50 ng m - 3 ) as compared to other studies conducted in Europe, and showed clear seasonal variation with maxima in winter and minima in summer. Vehicular traffic was identified as a major source of PAHs in the study area. Regarding particle size, a bimodal distribution was observed. The large sized particles exhibited an apparent seasonal variation with higher concentrations in winter than in summer. The dependences between particle size, PAH distribution and meteorological variables were studied with multivariate statistics. Three main sources of organic compounds were identified: combustion, vegetation, and atmospheric oxidation.

  13. The Atmospheric Fate of Organic Nitrogen Compounds

    NASA Astrophysics Data System (ADS)

    Borduas, Nadine

    Organic nitrogen compounds are present in our atmosphere from biogenic and anthropogenic sources and have impacts on air quality and climate. Due to recent advances in instrumentation, these compounds are being detected in the gas and particle phases, raising questions as to their source, processing and sinks in the environment. With their recently identified role as contributors to aerosol formation and growth, their novel large scale use as solvents in carbon capture and storage (CCS) technology and their emissions from cigarette smoke, it is now important to address the gaps in our understanding of the fate of organic nitrogen. Experimentally and theoretically, I studied the chemical atmospheric fate of specific organic nitrogen compounds in the amine, amide and isocyanate families, yielding information that can be used in chemical transport models to assess the fate of this emerging class of atmospheric molecules. I performed kinetic laboratory studies in a smog chamber to measure the room temperature rate coefficient for reaction with the hydroxyl radical of monoethanolamine, nicotine, and five different amides. I employed online-mass spectrometry techniques to quantify the oxidation products. I found that amines react quickly with OH radicals with lifetimes of a few hours under sunlit conditions, producing amides as oxidation products. My studies on amides revealed that they have much longer lifetimes in the atmosphere, ranging from a few hours to a week. Photo-oxidation of amides produces isocyanates and I investigated these mechanisms in detail using ab initio calculations. Furthermore, I experimentally measured isocyanic acid's Henry's Law constant as well as its hydrolysis rate constants to better understand its sinks in the atmosphere. Finally, I re-examined the structure-activity relationship (SAR) of organic nitrogen molecules for improved model parameterizations.

  14. Self assembly properties of primitive organic compounds

    NASA Technical Reports Server (NTRS)

    Deamer, D. W.

    1991-01-01

    A central event in the origin of life was the self-assembly of amphiphilic, lipid-like compounds into closed microenvironments. If a primitive macromolecular replicating system could be encapsulated within a vesicular membrane, the components of the system would share the same microenvironment, and the result would be a step toward true cellular function. The goal of our research has been to determine what amphiphilic molecules might plausibly have been available on the early Earth to participate in the formation of such boundary structures. To this end, we have investigated primitive organic mixtures present in carbonaceous meteorites such as the Murchison meteorite, which contains 1-2 percent of its mass in the form of organic carbon compounds. It is likely that such compounds contributed to the inventory of organic carbon on the prebiotic earth, and were available to participate in chemical evolution leading to the emergence of the first cellular life forms. We found that Murchison components extracted into non-polar solvent systems are surface active, a clear indication of amphiphilic character. One acidic fraction self-assembles into vesicular membranes that provide permeability barriers to polar solutes. Other evidence indicates that the membranes are bimolecular layers similar to those formed by contemporary membrane lipids. We conclude that bilayer membrane formation by primitive amphiphiles on the early Earth is feasible. However, only a minor fraction of acidic amphiphiles assembles into bilayers, and the resulting membranes require narrowly defined conditions of pH and ionic composition to be stable. It seems unlikely, therefore, that meteoritic infall was a direct source of membrane amphiphiles. Instead, the hydrocarbon components and their derivatives more probably would provide an organic stock available for chemical evolution. Our current research is directed at possible reactions which would generate substantial quantities of membranogenic

  15. BIODEGRADATION OF AROMATIC COMPOUNDS UNDER MIXED OXYGEN/DENITRIFYING CONDITIONS: A REVIEW

    EPA Science Inventory

    Bioremediation of aromatic hydrocarbons in groundwater and sediments is often limited by dissolved oxygen. Many aromatic hydrocarbons degrade very slowly or not at all under anaerobic conditions. Nitrate is a good alternative electron acceptor to oxygen, and denitrifying bacteria...

  16. GLOBAL INVENTORY OF VOLATILE COMPOUND EMISSIONS FROM ANTHROPOGENIC SOURCES

    EPA Science Inventory

    The report describes a global inventory anthropogenic volatile organic compound (VOC) emissions that includes a separate inventory for each of seven pollutant groups--paraffins, olefins, aromatics, formaldehyde, other aldehydes, other aromatics, and marginally reactive compounds....

  17. Aqueous and Tissue Residue-Based Interspecies Correlation Estimation Models Provide Conservative Hazard Estimates for Aromatic Compounds

    EPA Science Inventory

    Interspecies correlation estimation (ICE) models were developed for 30 nonpolar aromatic compounds to allow comparison of prediction accuracy between 2 data compilation approaches. Type 1 models used data combined across studies, and type 2 models used data combined only within s...

  18. Primary photochemistry of nitrated aromatic compounds: excited-state dynamics and NO· dissociation from 9-nitroanthracene.

    PubMed

    Plaza-Medina, Eddy F; Rodríguez-Córdoba, William; Morales-Cueto, Rodrigo; Peon, Jorge

    2011-02-10

    We report results of femtosecond-resolved ex-periments which elucidate the time scale for the primary photoinduced events in the model nitroaromatic compound 9-nitroanthracene. Through time-resolved fluorescence measurements, we observed the ultrafast decay of the initially excited singlet state, and through transient absorption experiments, we observed the spectral evolution associated with the formation of the relaxed phosphorescent T(1) state. Additionally, we have detected for the first time the accumulation of the anthryloxy radical which results from the nitro-group rearrangement and NO(•) dissociation from photoexcited 9-nitroanthracene, a photochemical channel which occurs in parallel with the formation of the phosphorescent state. The spectral evolution in this molecule is highly complex since both channels take place in similar time ranges of up to a few picoseconds. Despite this complexity, our experiments provide the general time scales in which the primary products are formed. In addition, we include calculations at the time-dependent density functional level of theory which distinguish the molecular orbitals responsible for the n-π* character of the "receiver" vibronic triplet states that couple with the first singlet state and promote the ultrafast transfer of population between the two manifolds. Comparisons with the isoelectronic compounds anthracene-9-carboxylic acid and its conjugated base, which are highly fluorescent, show that in these two compounds the near-isoenergeticity of the S(1) with an appropriate "receiver" triplet state is disrupted, providing support to the idea that a specific energy coincidence is important for the ultrafast population of the triplet manifold, prevalent in polycyclic nitrated aromatic compounds.

  19. Importance of heterocylic aromatic compounds in monitored natural attenuation for coal tar contaminated aquifers: A review

    NASA Astrophysics Data System (ADS)

    Blum, Philipp; Sagner, Anne; Tiehm, Andreas; Martus, Peter; Wendel, Thomas; Grathwohl, Peter

    2011-11-01

    NSO heterocycles (HET) are typical constituents of coal tars. However, HET are not yet routinely monitored, although HET are relatively toxic coal tar constituents. The main objectives of the study is therefore to review previous studies and to analyse HET at coal tar polluted sites in order to assess the relevance of HET as part of monitored natural attenuation (MNA) or any other long-term monitoring programme. Hence, natural attenuation of typical HET (indole, quinoline, carbazole, acridine, methylquinolines, thiophene, benzothiophene, dibenzothiophene, benzofuran, dibenzofuran, methylbenzofurans, dimethylbenzofurans and xanthene) were studied at three different field sites in Germany. Compound-specific plume lengths were determined for all main contaminant groups (BTEX, PAH and HET). The results show that the observed plume lengths are site-specific and are above 250 m, but less than 1000 m. The latter, i.e. the upper limit, however mainly depends on the level of investigation, the considered compound, the lowest measured concentration and/or the achieved compound-specific detection limit and therefore cannot be unequivocally defined. All downstream contaminant plumes exhibited HET concentrations above typical PAH concentrations indicating that some HET are generally persistent towards biodegradation compared to other coal tar constituents, which results in comparatively increased field-derived half-lives of HET. Additionally, this study provides a review on physicochemical and toxicological parameters of HET. For three well investigated sites in Germany, the biodegradation of HET is quantified using the centre line method (CLM) for the evaluation of bulk attenuation rate constants. The results of the present and previous studies suggest that implementation of a comprehensive monitoring programme for heterocyclic aromatic compounds is relevant at sites, if MNA is considered in risk assessment and for remediation.

  20. Compounds having aromatic rings and side-chain amide-functionality and a method for transporting monovalent anions across biological membranes using the same

    DOEpatents

    Davis, Jeffery T.; Sidorov, Vladimir; Kotch, Frank W.

    2008-04-08

    A compound containing at least two aromatic rings covalently bonded together, with each aromatic ring containing at least one oxyacetamide-based side chain, the compound being capable of forming a chloride ion channel across a lipid bilayer, and transporting chloride ion across the lipid bilayer.

  1. Organic compounds in produced waters from shale gas wells.

    PubMed

    Maguire-Boyle, Samuel J; Barron, Andrew R

    2014-01-01

    A detailed analysis is reported of the organic composition of produced water samples from typical shale gas wells in the Marcellus (PA), Eagle Ford (TX), and Barnett (NM) formations. The quality of shale gas produced (and frac flowback) waters is a current environmental concern and disposal problem for producers. Re-use of produced water for hydraulic fracturing is being encouraged; however, knowledge of the organic impurities is important in determining the method of treatment. The metal content was determined by inductively coupled plasma optical emission spectrometry (ICP-OES). Mineral elements are expected depending on the reservoir geology and salts used in hydraulic fracturing; however, significant levels of other transition metals and heavier main group elements are observed. The presence of scaling elements (Ca and Ba) is related to the pH of the water rather than total dissolved solids (TDS). Using gas chromatography mass spectrometry (GC/MS) analysis of the chloroform extracts of the produced water samples, a plethora of organic compounds were identified. In each water sample, the majority of organics are saturated (aliphatic), and only a small fraction comes under aromatic, resin, and asphaltene categories. Unlike coalbed methane produced water it appears that shale oil/gas produced water does not contain significant quantities of polyaromatic hydrocarbons reducing the potential health hazard. Marcellus and Barnett produced waters contain predominantly C6-C16 hydrocarbons, while the Eagle Ford produced water shows the highest concentration in the C17-C30 range. The structures of the saturated hydrocarbons identified generally follows the trend of linear > branched > cyclic. Heterocyclic compounds are identified with the largest fraction being fatty alcohols, esters, and ethers. However, the presence of various fatty acid phthalate esters in the Barnett and Marcellus produced waters can be related to their use in drilling fluids and breaker additives

  2. Determination of aromatic tracer compounds for environmental tobacco smoke aerosol by two step laser mass spectrometry

    NASA Astrophysics Data System (ADS)

    Morrical, Brad D.; Zenobi, Renato

    Cigarette smoking is a major cause of indoor aerosol pollution. Determination of exposure to environmental tobacco smoke (ETS) aerosol is critical to understanding health effects. Sizing studies have shown that ETS has a size distribution that is efficiently deposited into the lungs and can therefore provide effective delivery of carcinogenic compounds into the human body. Two-step laser mass spectrometry is used to analyze aromatic compounds on aerosols collected from a smoking lobby. The determination and suitability of ETS tracers on aerosols is examined. Additionally, the transport of aerosol from the smoking lobby is examined to determine what effect deposition and dilution have on the mass spectrum observed. Results from the analysis of ETS, both from lobby samples and direct cigarette sampling, show that several unique peaks are present in the mass spectrum when compared to other combustion sources, such as automobiles and diesel trucks. In particular, ions at m/ z 118, 132, 146, and 160 are consistently present and are not found in other combustion sources. For the indoor environment, where chemical transformation is much less rapid than in the outdoor environment, these ions were found to be present as soon as the first smokers appeared and persisted over the course of the day. Aerosol samples taken in the morning prior to the presence of smokers in the lobby reveal the presence of skeletal PAHs, indicative of outdoor urban traffic aerosol penetration into the building.

  3. Induced production of brominated aromatic compounds in the alga Ceramium tenuicorne.

    PubMed

    Dahlgren, Elin; Enhus, Carolina; Lindqvist, Dennis; Eklund, Britta; Asplund, Lillemor

    2015-11-01

    In the Baltic Sea, high concentrations of toxic brominated aromatic compounds have been detected in all compartments of the marine food web. A growing body of evidence points towards filamentous algae as a natural producer of these chemicals. However, little is known about the effects of environmental factors and life history on algal production of brominated compounds. In this study, several congeners of methoxylated polybrominated diphenyl ethers (MeO-PBDEs), hydroxylated polybrominated diphenyl ethers (OH-PBDEs) and brominated phenols (BPs) were identified in a naturally growing filamentous red algal species (Ceramium tenuicorne) in the Baltic Sea. The identified substances displayed large seasonal variations in the alga with a concentration peak in July. Production of MeO-/OH-PBDEs and BPs by C. tenuicorne was also established in isolated clonal material grown in a controlled laboratory setting. Based on three replicates, herbivory, as well as elevated levels of light and salinity in the culture medium, significantly increased the production of 2,4,6-tribromophenol (2,4,6-TBP). Investigation of differences in production between the isomorphic female, male and diploid clonal life stages of the alga grown in the laboratory revealed a significantly higher production of 2,4,6-TBP in the brackish water female gametophytes, compared to the corresponding marine gametophytes. Even higher concentrations of 2,4,6-TBP were produced by marine male gametophytes and sporophytes.

  4. The Highly Conserved Escherichia coli Transcription Factor YhaJ Regulates Aromatic Compound Degradation

    PubMed Central

    Palevsky, Noa; Shemer, Benjamin; Connolly, James P. R.; Belkin, Shimshon

    2016-01-01

    The aromatic compound 2,4-dinitrotoluene (DNT), a common impurity in 2,4,6-trinitrotoluene (TNT) production, has been suggested as a tracer for the presence of TNT-based landmines due to its stability and high volatility. We have previously described an Escherichia coli bioreporter capable of detecting the presence of DNT vapors, harboring a fusion of the yqjF gene promoter to a reporter element. However, the DNT metabolite which is the direct inducer of yqjF, has not yet been identified, nor has the regulatory mechanism of the induction been clarified. We demonstrate here that the YhaJ protein, a member of the LysR type family, acts as a transcriptional regulator of yqjF activation, as well as of a panel of additional E. coli genes. This group of genes share a common sequence motif in their promoters, which is suggested here as a putative YhaJ-box. In addition, we have linked YhaJ to the regulation of quinol-like compound degradation in the cell, and identified yhaK as playing a role in the degradation of DNT. PMID:27713734

  5. Deviations from Ideal Sublimation Vapor Pressure Behavior in Mixtures of Polycyclic Aromatic Compounds with Interacting Heteroatoms.

    PubMed

    Goldfarb, Jillian L; Suuberg, Eric M

    2010-08-01

    Despite the relatively small atomic fraction of a given heteroatom in a binary mixture of polycyclic aromatic compounds (PAC), the inclusion of heteroatomic substituted compounds can significantly impact mixture vapor pressure behavior over a wide range of temperatures. The vapor pressures of several binary PAC mixtures containing various heteroatoms show varying behavior, from practically ideal behavior following Raoult's law to significant deviations from ideality depending on the heteroatom(s) present in the mixture. Mixtures were synthesized using the quench-cool technique with equimolar amounts of two PAC, both containing heteroatoms such as aldehyde, carboxyl, nitrogen, and sulfur substituent groups. For some mixtures, deviation from ideality is inversely related to temperature, though in other cases we see deviations from ideality increasing with temperature, whereas some appear independent of temperature. Most commonly we see lower vapor pressures than predicted by Raoult's law, which indicates that the interacting heteroatoms prefer the solid mixture phase as opposed to the vapor phase. Although negative deviations predominate from Raoult's Law, the varying mixtures investigated show both higher and lower enthalpies and entropies of sublimation than predicted. In each mixture, a higher enthalpy of sublimation leads to higher entropy of sublimation than predicted, and vice versa.

  6. Development of a flow-injection fluorescence method for estimation of total polycyclic aromatic compounds in asphalt fumes.

    PubMed

    Neumeister, Charles E; Olsen, Larry D; Dollberg, Donald D

    2003-01-01

    Traditionally, measurements of specific polycyclic aromatic compounds (PACs) have been attempted as an estimate of asphalt fume exposure. However, asphalt fumes contain numerous alkyl substituted PACs, including PACs containing heteroatoms of nitrogen, oxygen, and sulfur. Many of these compounds coelute precluding the resolution of the individual compounds resulting in ambiguous data. Moreover, many researchers believe that some observed health hazards are associated with PACs overall and not just a few select PACs. Therefore, NIOSH method 5800 was developed to evaluate total PACs as a chemical class in asphalt fumes. Asphalt fume samples were collected on a poly(tetrafluoroethylene) filter backed by an XAD-2 sorbent tube. The samples were extracted with hexane; then, a cyano-solid-phase-extraction column was used to remove the polar compounds while the aliphatic and aromatic compounds were eluted with hexane. An equal volume of dimethyl sulfoxide (DMSO) was added to the hexane extract, causing the aromatic compounds to partition into the DMSO, thus isolating the PACs. The PACs were then analyzed for fluorescence using a flow-injection method with two fluorescence detectors. Wavelength settings for the first detector (254-nm excitation, 370-nm emission) emphasized the 2- to 4-ring PACs that may cause eye and respiratory tract irritation. Wavelength settings of the second detector (254-nm excitation, 400-nm emission) emphasized the 4- and higher-ring PACs that are often mutagenic and possibly carcinogenic.

  7. Effect of Biofilm Formation by Oenococcus oeni on Malolactic Fermentation and the Release of Aromatic Compounds in Wine

    PubMed Central

    Bastard, Alexandre; Coelho, Christian; Briandet, Romain; Canette, Alexis; Gougeon, Régis; Alexandre, Hervé; Guzzo, Jean; Weidmann, Stéphanie

    2016-01-01

    The winemaking process involves the alcoholic fermentation of must, often followed by malolactic fermentation (MLF). The latter, mainly carried out by the lactic acid bacterium Oenococcus oeni, is used to improve wine quality when acidity reduction is required. Moreover, it prevents microbial spoilage and improves the wine’s organoleptic profile. Prior observations showed that O. oeni is able to resist several months in harsh wine conditions when adhered on oak barrels. Since biofilm is a prevailing microbial lifestyle in natural environments, the capacity of O. oeni to form biofilms was investigated on winemaking material such as stainless steel and oak chips. Scanning Electron Microscopy and Confocal Laser Scanning Microscopy showed that O. oeni was able to adhere to these surfaces and form spatially organized microcolonies embedded in extracellular substances. To assess the competitive advantage of this mode of life in wine, the properties of biofilm and planktonic cells were compared after inoculation in a fermented must (pH 3.5 or 3.2 and 12% ethanol) The results indicated that the biofilm culture of O. oeni conferred (i) increased tolerance to wine stress, and (ii) functional performance with effective malolactic activities. Relative gene expression focusing on stress genes and genes involved in EPS synthesis was investigated in a mature biofilm and emphasized the role of the matrix in increased biofilm resistance. As oak is commonly used in wine aging, we focused on the O. oeni biofilm on this material and its contribution to the development of wine color and the release of aromatic compounds. Analytical chromatography was used to target the main oak aging compounds such as vanillin, gaiacol, eugenol, whisky-lactones, and furfural. The results reveal that O. oeni biofilm developed on oak can modulate the wood-wine transfer of volatile aromatic compounds during MLF and aging by decreasing furfural, gaiacol, and eugenol in particular. This work showed that O

  8. Biogenic volatile organic compounds - small is beautiful

    NASA Astrophysics Data System (ADS)

    Owen, S. M.; Asensio, D.; Li, Q.; Penuelas, J.

    2012-12-01

    While canopy and regional scale flux measurements of biogenic volatile organic compounds (bVOCs) are essential to obtain an integrated picture of total compound reaching the atmosphere, many fascinating and important emission details are waiting to be discovered at smaller scales, in different ecological and functional compartments. We concentrate on bVOCs below ground to <2m above ground level. Emissions at leaf scale are well documented and widely presented, and are not discussed here. Instead we describe some details of recent research on rhizosphere bVOCs, and bVOCs associated with pollination of flowers. Although bVOC emissions from soil surfaces are small, bVOCs are exuded by roots of some plant species, and can be extracted from decaying litter. Naturally occurring monoterpenes in the rhizosphere provide a specialised carbon source for micro-organisms, helping to define the micro-organism community structure, and impacting on nutrient cycles which are partly controlled by microorganisms. Naturally occurring monoterpenes in the soil system could also affect the aboveground structure of ecosystems because of their role in plant defence strategies and as mediating chemicals in allelopathy. A gradient of monoterpene concentration was found in soil around Pinus sylvestris and Pinus halepensis, decreasing with distance from the tree. Some compounds (α-pinene, sabinene, humulene and caryophyllene) in mineral soil were linearly correlated with the total amount of each compound in the overlying litter, indicating that litter might be the dominant source of these compounds. However, α-pinene did not fall within the correlation, indicating a source other than litter, probably root exudates. We also show that rhizosphere bVOCs can be a carbon source for soil microbes. In a horizontal gradient from Populus tremula trees, microbes closest to the tree trunk were better enzymatically equipped to metabolise labeled monoterpene substrate. Monoterpenes can also increase the

  9. Bromination of aromatic compounds by residual bromide in sodium chloride matrix modifier salt during heated headspace GC/MS analysis.

    PubMed

    Fine, Dennis D; Ko, Saebom; Huling, Scott

    2013-12-15

    Analytical artifacts attributed to the bromination of toluene, xylenes, and trimethylbenzenes were found during the heated headspace gas chromatography/mass spectrometry (GC/MS) analysis of aqueous samples. The aqueous samples were produced from Fenton-like chemical oxidation reactions and contained aromatic compounds, hydrogen peroxide (H2O2), and ferric sulfate. Prior to GC/MS headspace analysis, the samples were acidified (pH<2), and sodium chloride was amended to the headspace vial as a matrix modifier. The brominated artifacts were generated during heated headspace analysis. Further, when samples were spiked with a mixture of volatile chlorinated and aromatic compounds (50 µg/L), poor spike recoveries of toluene and xylenes occurred, and in some cases complete loss of trimethylbenzenes and naphthalene resulted. Where poor recovery of aromatic spike compounds occurred, brominated aromatic compounds were found. The only significant source of bromine in the reaction scheme is the bromide typically present (<0.01% w/w) in the sodium chloride amended to the samples. Conversely, brominated artifacts were absent when a buffered salt mixture composed of sodium chloride and potassium phosphate dibasic/monobasic was used as a matrix modifier and raised the sample pH (pH~6). This indicated that the brominated artifacts resulted from the reaction of the aromatic compounds with BrCl, which was formed by the reaction of H2O2, chloride, and bromide under acidic conditions. An alternative matrix modifier salt is recommended that prevents the bromination reaction and avoids these deleterious effects on sample integrity during headspace analysis.

  10. Dry deposition of polycyclic aromatic compounds to various land covers in the Athabasca oil sands region

    NASA Astrophysics Data System (ADS)

    Zhang, Leiming; Cheng, Irene; Wu, Zhiyong; Harner, Tom; Schuster, Jasmin; Charland, Jean-Pierre; Muir, Derek; Parnis, J. Mark

    2015-09-01

    A framework was developed to estimate dry deposition of polycyclic aromatic compounds (PACs), including 17 polycyclic aromatic hydrocarbons (PAHs), 21 alkylated PAHs, and 5 parent and alkylated dibenzothiophenes (DBTs), to various land covers surrounding three monitoring sites in the Athabasca oil sands region. Modeled dry deposition velocities for various gaseous PACs and over various land covers were mostly in the range of 0.01-0.5 cm s-1 with median and annual mean values between 0.08 and 0.24 cm s-1, comparable with literature values obtained from field studies. Annual dry deposition of the sum of PAHs was estimated to range from 330 to 560 μg m-2 over forested canopies surrounding the three sites and from 270 to 490 μg m-2 over grass and shrubs. The corresponding values are 3920-5380 and 2850-4920 μg m-2 for the sum of 21 alkylated PAHs, and are 230-1120 and 450-930 μg m-2 for the sum of 5 DBTs. The three monitoring sites are situated nearby the Athabasca River, and the direct annual atmospheric dry deposition to water surface was estimated to range from 350 to 500, 3170 to 4530, and 170 to 840 μg m-2 for PAHs, alkylated PAHs, and DBTs, respectively. Alkylated PAHs contributed 80% of the total dry and 60% of the total wet deposition budget, suggesting the importance of including this group of PAHs in the atmospheric deposition budget estimation for subsequent ecosystem impact studies.

  11. Palladium catalyzed hydrogenation of bio-oils and organic compounds

    DOEpatents

    Elliott, Douglas C [Kennewick, WA; Hu, Jianli [Richland, WA; Hart,; Todd, R [Kennewick, WA; Neuenschwander, Gary G [Burbank, WA

    2011-06-07

    The invention provides palladium-catalyzed hydrogenations of bio-oils and certain organic compounds. Experimental results have shown unexpected and superior results for palladium-catalyzed hydrogenations of organic compounds typically found in bio-oils.

  12. Palladium catalyzed hydrogenation of bio-oils and organic compounds

    DOEpatents

    Elliott, Douglas C.; Hu, Jianli; Hart, Todd R.; Neuenschwander, Gary G.

    2008-09-16

    The invention provides palladium-catalyzed hydrogenations of bio-oils and certain organic compounds. Experimental results have shown unexpected and superior results for palladium-catalyzed hydrogenations of organic compounds typically found in bio-oils.

  13. A method of isolating organic compounds present in water

    NASA Technical Reports Server (NTRS)

    Calder, G. V.; Fritz, J.; Junk, G. A.

    1972-01-01

    Water sample is passed through a column containing macroreticular resin, which absorbs only nonionic organic compounds. These compounds are selectively separated using aqueous eluents of varying pH, or completely exuded with small amount of an organic eluent.

  14. Origin of the conformational modulation of the 13C NMR chemical shift of methoxy groups in aromatic natural compounds.

    PubMed

    Toušek, Jaromír; Straka, Michal; Sklenář, Vladimír; Marek, Radek

    2013-01-24

    The interpretation of nuclear magnetic resonance (NMR) parameters is essential to understanding experimental observations at the molecular and supramolecular levels and to designing new and more efficient molecular probes. In many aromatic natural compounds, unusual (13)C NMR chemical shifts have been reported for out-of-plane methoxy groups bonded to the aromatic ring (~62 ppm as compared to the typical value of ~56 ppm for an aromatic methoxy group). Here, we analyzed this phenomenon for a series of aromatic natural compounds using Density Functional Theory (DFT) calculations. First, we checked the methodology used to optimize the structure and calculate the NMR chemical shifts in aromatic compounds. The conformational effects of the methoxy group on the (13)C NMR chemical shift then were interpreted by the Natural Bond Orbital (NBO) and Natural Chemical Shift (NCS) approaches, and by excitation analysis of the chemical shifts, breaking down the total nuclear shielding tensor into the contributions from the different occupied orbitals and their magnetic interactions with virtual orbitals. We discovered that the atypical (13)C NMR chemical shifts observed are not directly related to a different conjugation of the lone pair of electrons of the methoxy oxygen with the aromatic ring, as has been suggested. Our analysis indicates that rotation of the methoxy group induces changes in the virtual molecular orbital space, which, in turn, correlate with the predominant part of the contribution of the paramagnetic deshielding connected with the magnetic interactions of the BD(CMet-H)→BD*(CMet-OMet) orbitals, resulting in the experimentally observed deshielding of the (13)C NMR resonance of the out-of-plane methoxy group.

  15. Exposure to volatile organic compounds: Comparison among different transportation modes

    NASA Astrophysics Data System (ADS)

    Do, Duc Hoai; Van Langenhove, Herman; Chigbo, Stephen Izuchukwu; Amare, Abebech Nuguse; Demeestere, Kristof; Walgraeve, Christophe

    2014-09-01

    The increasing trend of promoting public transportation (bus tram, metro, train) and more environmental friendly and sustainable non fossil-fuel alternatives (walking, cycling etc) as substitutes for auto vehicles brings forward new questions with regard to pollutant levels to which commuters are exposed. In this study, three transportation modes (tram, auto vehicle and bicycle) are studied and concentration levels of 84 volatile organic compounds (VOCs) (hydrocarbons, aromatic hydrocarbons, oxygen containing hydrocarbons, terpenes and halogenated compounds) are measured along a route in the city of Ghent, Belgium. The concentration levels are obtained by active sampling on Tenax TA sorbent tubes followed by thermal desorption gas chromatography mass spectrometry (TD-GC-MS) using deuterated toluene as an internal standard. The median total VOC concentrations for the tram mode (33 μg/m³) is 1.7 times higher than that of the bicycle mode (20 μg/m³) and 1.5 times higher than for the car mode (22 μg/m³). It is found that aromatic hydrocarbons account for a significant proportion in the total VOCs concentration (TVOCs) being as high as 41-57%, 59-72% and 58-72% for the tram, car and bicycle respectively. In all transportation modes, there was a high (r > 0.6) degree of correlation between BTEX compounds, isopropylbenzene, n-propylbenzene, 1,3,5-trimethylbenzene and 1,2,4-trimethylbenzene. When comparing time weighed average concentrations along a fixed route in Ghent, it is found that commuters using the tram mode experience the highest TVOCs concentration levels. However, next to the concentration level to which commuters are exposed, the physical activity level involving the mode of transportation is important to assess the exposure to toxic VOCs. It is proven that the commuter using a bicycle (4.3 ± 1.5 μg) inhales seven and nine times more benzene compared to the commuter using the car and tram respectively, when the same route is followed.

  16. Volatile Organic Compound Emissions from Humans Indoors.

    PubMed

    Tang, Xiaochen; Misztal, Pawel K; Nazaroff, William W; Goldstein, Allen H

    2016-12-06

    Research on the sources of indoor airborne chemicals has traditionally focused on outdoor air, building materials, furnishings, and activities such as smoking, cooking, and cleaning. Relatively little research has examined the direct role of occupant emissions, even though this source clearly contributes to indoor volatile organic compounds (VOCs) and influences indoor chemistry. In this work, we quantify occupant-related gaseous VOC emissions in a university classroom using a proton-transfer-reaction time-of-flight mass spectrometer. Time-resolved concentrations of VOCs in room air and supply air were measured continuously during occupied and unoccupied periods. The emission factor for each human-emitted VOC was determined by dividing the occupant-associated source rate by the corresponding occupancy. Among the most abundant species detected were compounds associated with personal care products. Also prominent were human metabolic emissions, such as isoprene, methanol, acetone, and acetic acid. Additional sources included human skin oil oxidation by ozone, producing compounds such as 4-oxopentanal (4-OPA) and 6-methyl-5-hepten-2-one (6-MHO). By mass, human-emitted VOCs were the dominant source (57%) during occupied periods in a well-ventilated classroom, with ventilation supply air the second most important (35%), and indoor nonoccupant emissions the least (8%). The total occupant-associated VOC emission factor was 6.3 mg h(-1) per person.

  17. A Comparative study of Volatile Organic Compounds from two desert plant species growing in Southern Arizona

    NASA Astrophysics Data System (ADS)

    Paasche, K. M.; Meyers, K.; Jardine, K.

    2012-12-01

    Throughout their lives, plants are subjected to a multitude of stressors, ranging from herbivory to changes in weather. In order to survive, plants have created an arsenal of volatile organic compounds (VOCs), including green leaf volatiles (GLVs) and aromatic compounds, to combat these stressors. In this study, two plant species, Baccharis salicifolia (Seep willow) and Dodonaea viscosa (Hopbush) were examined for isoprenoids, GLVs, and aromatic compound emissions. Although, the species are not related, they should share some emitted compounds as they can be seen growing in the same environment, though the majority of the emitted compounds should remain unique to each species type. Both the Seep willow, sampled in Catalina State Park, and the Hopbush, sampled at Biosphere 2, were sampled using a Teflon bag enclosure connected to an apex lite air-sampling device and a thermal desorption (TD) tube, which was used to collect the emitted compounds. TD tube samples were analyzed using a Unity 2 thermal desorption system, which was directly connected to a 5975C series gas chromatograph/electron impact mass spectrometer with a triple-axis detector. The major compounds emitted from the Seep willow were GLVs (Octanal, Decanal, and Nonanal) and aromatics (Benzoic acid, Benzaldehyde, 1,2,3-Trifluorobenzene, and Acetophenone). The major compounds emitted from the Hopbush were isoprene and monoterpenes (1R-α-Pinene, Limonene, and α-Phellandrene.) Our results show the two species emit completely different compounds from each other, which could indicate adaptive differences. The Hopbush may be a hardier species better adapted to the Arizona environment as isoprene and monoterpenes have been indicated in thermo tolerance. GLVs on the other hand indicate the Seep willow is under severe stress.

  18. Study of 106 organic and inorganic compounds in the Salmonella/microsome test.

    PubMed

    De Flora, S

    1981-01-01

    One hundred and six compounds, subdivided into 12 chemical classes (5 polycyclic aromatic hydrocarbons, 7 epoxides and N-oxides, 5 nitro aromatics and heterocycles, 12 aromatic and heterocyclic amines, 2 azo compounds, 17 hydrazine derivatives, 16 miscellaneous aliphatics, 5 miscellaneous heterocycles, 11 miscellaneous organics, 11 hexavalent and 7 trivalent chromium compounds, 8 miscellaneous inorganics), were studied in the Salmonella/microsome test. Fifty-eight of them (54.7%) were found to be mutagenic and 4 additional compounds (3.8%) yielded a positive response following nitrosation in human gastric juice. The results are presented in a tabulated form, providing the following information for each test compound: (a) mutagenic response in 5 S. typhimurium his- strains (TA1535, TA1537, TA1538, TA98, TA100); (b) range of activity for positive compounds or maximum dose tested for negative compounds (in nmol/plate); (c) mutagenic potency (in revertants/nmol compound), varying over a 6.5 x 10(6)-fold range; (d) effect of S-9 mix containing rat (Aroclor)liver S-9 fractions on the mutagenic response (activation, increase, no change or decrease); (e) remarks concerning the influence of other metabolic systems (up to 10 different rat tissue S-9 fractions, mouse S-9 fractions, human S-9 fractions, cell preparations or biological fluids), the interaction between different compounds, the stability and the formation of mutagenic derivatives in human gastric juice and other experimental details. Overlapping of mutagenicity and carcinogenicity data was not evaluated, since the experimental protocol intentionally included a number of non-carcinogenic mutagens and of non-mutagenic carcinogens, with the aim of explaining in some cases the conflicting nature of in vivo and in vitro conclusions.

  19. A new architecture for high spin organics based on Baird's rule of 4n electron triplet aromatics.

    PubMed

    Mauksch, Michael; Tsogoeva, Svetlana B

    2017-02-08

    Due to the absence of open subshells (unlike transition metal compounds), stable high spin organic molecules are rare and are mostly limited to states of low multiplicity. As an alternative to high multiplicity polyradicals and polycarbenes, with their small energetic separation of different spin isomers, it is demonstrated that Baird's rule of 4n electron aromaticity in the triplet electronic state allows, in principle, the design of polycyclic high spin organics with high spin multiplicity in the electronic ground state and a large energetic separation for other spin states. Energy spacing between spin isomers is dictated here by the aromaticity or antiaromaticity of individual cycles (taking into account all π electrons), rather than by a spin Hamiltonian alone (accounting only for unpaired spin electrons). As a proof of concept, dyads of the cyclopentadienyl cation (which has been reported to possess a triplet ground state) have been computationally found to possess a quintet electronic ground state with two ferromagnetically coupled Baird aromatic rings (with SCF-GIAO NICS(0) = -4.6 and -4.4, respectively; "NICS" is "nucleus independent chemical shift") at the CASMP2(8,10)/6-311G*//CASSCF(8,10)/6-311G* level, which is 48.3 kcal mol(-1) lower in energy than the C2 open shell singlet with two antiaromatic rings (with NICS = +17.4), and 19.7 kcal mol(-1) below the triplet which has one aromatic and one antiaromatic ring, with NICS = -4.8 and +45.0, respectively. Triads of the cyclopentadienyl cation in linear and branched topologies are also proposed to be ground states of maximum spin multiplicity by computations at the DFT and CCSD(T)/6-31G//UB3LYP/6-311G* levels.

  20. Volatile Organic Compound Analysis in Istanbul

    NASA Astrophysics Data System (ADS)

    Ćapraz, Ö.; Deniz, A.; Öztürk, A.; Incecik, S.; Toros, H.; Coşkun, M.

    2012-04-01

    Volatile Organic Compound Analysis in Istanbul Ö. Çapraz1, A. Deniz1,3, A. Ozturk2, S. Incecik1, H. Toros1 and, M. Coskun1 (1) Istanbul Technical University, Faculty of Aeronautics and Astronautics, Department of Meteorology, 34469, Maslak, Istanbul, Turkey. (2) Istanbul Technical University, Faculty of Chemical and Metallurgical, Chemical Engineering, 34469, Maslak, Istanbul, Turkey. (3) Marmara Clean Air Center, Ministry of Environment and Urbanization, Nişantaşı, 34365, İstanbul, Turkey. One of the major problems of megacities is air pollution. Therefore, investigations of air quality are increasing and supported by many institutions in recent years. Air pollution in Istanbul contains many components that originate from a wide range of industrial, heating, motor vehicle, and natural emissions sources. VOC, originating mainly from automobile exhaust, secondhand smoke and building materials, are one of these compounds containing some thousands of chemicals. In spite of the risks to human health, relatively little is known about the levels of VOC in Istanbul. In this study, ambient air quality measurements of 32 VOCs including hydrocarbons, halogenated hydrocarbons and carbonyls were conducted in Kağıthane (Golden Horn) region in Istanbul during the winter season of 2011 in order to develop the necessary scientific framework for the subsequent developments. Kağıthane creek valley is the source part of the Golden Horn and one of the most polluted locations in Istanbul due to its topographical form and pollutant sources in the region. In this valley, horizontal and vertical atmospheric motions are very weak. The target compounds most commonly found were benzene, toluene, xylene and ethyl benzene. Concentrations of total hydrocarbons ranged between 1.0 and 10.0 parts per billion, by volume (ppbv). Ambient air levels of halogenated hydrocarbons appeared to exhibit unique spatial variations and no single factor seemed to explain trends for this group of

  1. Organic Chemistry Self Instructional Package 15: Benzene, Aromaticity.

    ERIC Educational Resources Information Center

    Zdravkovich, V.

    This booklet, one of a series of 17 developed at Prince George's Community College, Largo, Maryland, provides an individualized, self-paced undergraduate organic chemistry instruction module designed to augment any course in organic chemistry but particularly those taught using the text "Organic Chemistry" by Morrison and Boyd. The…

  2. Semivolatile organic compounds in indoor environments

    NASA Astrophysics Data System (ADS)

    Weschler, Charles J.; Nazaroff, William W.

    Semivolatile organic compounds (SVOCs) are ubiquitous in indoor environments, redistributing from their original sources to all indoor surfaces. Exposures resulting from their indoor presence contribute to detectable body burdens of diverse SVOCs, including pesticides, plasticizers, and flame retardants. This paper critically examines equilibrium partitioning of SVOCs among indoor compartments. It proceeds to evaluate kinetic constraints on sorptive partitioning to organic matter on fixed surfaces and airborne particles. Analyses indicate that equilibrium partitioning is achieved faster for particles than for typical indoor surfaces; indeed, for a strongly sorbing SVOC and a thick sorptive reservoir, equilibrium partitioning is never achieved. Mass-balance considerations are used to develop physical-science-based models that connect source- and sink-rates to airborne concentrations for commonly encountered situations, such as the application of a pesticide or the emission of a plasticizer or flame retardant from its host material. Calculations suggest that many SVOCs have long indoor persistence, even after the primary source is removed. If the only removal mechanism is ventilation, moderately sorbing compounds ( Koa > 10 10) may persist indoors for hundreds to thousands of hours, while strongly sorbing compounds ( Koa > 10 12) may persist for years. The paper concludes by applying the newly developed framework to explore exposure pathways of building occupants to indoor SVOCs. Accumulation of SVOCs as a consequence of direct air-to-human transport is shown to be potentially large, with a maximum indoor-air processing rate of 10-20 m 3/h for SVOC uptake by human skin, hair and clothing. Levels on human skin calculated with a simple model of direct air-to-skin transfer agree remarkably well with levels measured in dermal hand wipes for SVOCs possessing a wide range of octanol-air partition coefficients.

  3. Influence of polychlorinated aromatic compounds on the biotransformation and toxicity of organophosphorus pesticides (OP) to the Daphnia magna

    SciTech Connect

    Tonkopii, V.; Zagrebin, A.; Sherstneva, L.

    1995-12-31

    The effect of different polychlorinated aromatics (DDT, Aroclor 1254, certain polychlorinated biphenyls and dibenzofurans) on the toxicity of OP (DDVP paraoxon, malaoxon) to Daphnia magna was studied. Pretreatment of daphnids with chlorinated compounds during 72 hours in nontoxic concentrations (1/5--1/20 CL{sub 50}) has been shown to reduce the toxicity of OP for hydrobionts. For study of influence of chlorinated compounds on biotransformation of OP the activity of enzymes which are hydrolyzing the OP was investigated in Daphnia`s homogenates or microsomes. The activity of carboxylesterase (tributyrinase, aliesterase) and arylesterase (phosphorylphosphatase) with usage as substrates accordingly {alpha}-naphthylacetate and paraoxon was measured. Besides that the activity of cholinesterase with application of propionylthiocholine as substrate was determined. After polychlorinated aromatic compounds treatment of daphnids activities of both aryl-and carboxylesterase increased markedly. It decreased the inhibition of Daphnia`s cholinesterase caused by incubation with OP in concentrations 0.5--1.0 CL{sub 50}. Thus the induction by chlorinate aromatics of OP metabolizing enzymes seems to play the important role in reduction of OP toxicity to Daphnia magna. Perhaps the aryl- and carboxylesterase of Daphnia can be used as biomarkers of pollution by polychlorinated aromatics in water.

  4. Qualitative analysis of volatile organic compounds on biochar.

    PubMed

    Spokas, Kurt A; Novak, Jeffrey M; Stewart, Catherine E; Cantrell, Keri B; Uchimiya, Minori; Dusaire, Martin G; Ro, Kyoung S

    2011-10-01

    Qualitative identification of sorbed volatile organic compounds (VOCs) on biochar was conducted by headspace thermal desorption coupled to capillary gas chromatographic-mass spectrometry. VOCs may have a mechanistic role influencing plant and microbial responses to biochar amendments, since VOCs can directly inhibit/stimulate microbial and plant processes. Over 70 biochars encompassing a variety of parent feedstocks and manufacturing processes were evaluated and were observed to possess diverse sorbed VOC composition. There were over 140 individual chemical compounds thermally desorbed from some biochars, with hydrothermal carbonization (HTC) and fast pyrolysis biochars typically possessing the greatest number of sorbed volatiles. In contrast, gasification, thermal or chemical processed biochars, soil kiln mound, and open pit biochars possessed low to non-detectable levels of VOCs. Slow pyrolysis biochars were highly variable in terms of their sorbed VOC content. There were no clear feedstock dependencies to the sorbed VOC composition, suggesting a stronger linkage with biochar production conditions coupled to post-production handling and processing. Lower pyrolytic temperatures (⩽350°C) produced biochars with sorbed VOCs consisting of short carbon chain aldehydes, furans and ketones; elevated temperature biochars (>350°C) typically were dominated by sorbed aromatic compounds and longer carbon chain hydrocarbons. The presence of oxygen during pyrolysis also reduced sorbed VOCs. These compositional results suggest that sorbed VOCs are highly variable and that their chemical dissimilarity could play a role in the wide variety of plant and soil microbial responses to biochar soil amendment noted in the literature. This variability in VOC composition may argue for VOC characterization before land application to predict possible agroecosystem effects.

  5. Polycyclic aromatic hydrocarbons in surface sediments and marine organisms from the Daya Bay, South China.

    PubMed

    Sun, Run-Xia; Lin, Qin; Ke, Chang-Liang; Du, Fei-Yan; Gu, Yang-Guang; Cao, Kun; Luo, Xiao-Jun; Mai, Bi-Xian

    2016-02-15

    Polycyclic aromatic hydrocarbons (PAHs) were investigated in the marine ecosystem of the Daya Bay, South China. The PAH concentrations ranged from 340 to 710 ng/g dry weight in the sediments and from 110 to 520 ng/g wet weight in marine organisms, respectively. The dominant compounds were three- and four-ring PAHs in the sediments (53%-89%) and two- and three-ring PAHs in the marine species (67%-94%), respectively. PAHs mainly originated from both pyrolytic and petrogenic sources. Comparison with the effects-based sediment quality guideline values suggested that the ecological risk caused by the total PAHs was relatively low (less than 25% incidence of adverse effects) in the sedimentary environment. The median cancer risk level via seafood consumption (1.6 × 10(-5) for urban residents and 1.2 × 10(-5) for rural residents, respectively) was slightly higher than the maximum admissible level (10(-5)) set by US EPA, but lower than the priority risk level (10(-4)).

  6. Determination of Volatile Organic Compounds in the Atmosphere Using Two Complementary Analysis Techniques.

    PubMed

    Alonso, L; Durana, N; Navazo, M; García, J A; Ilardia, J L

    1999-08-01

    During a preliminary field campaign of volatile organic compound (VOC) measurements carried out in an urban area, two complementary analysis techniques were applied to establish the technical and scientific bases for a strategy to monitor and control VOCs and photochemical oxidants in the Autonomous Community of the Basque Country. Integrated sampling was conducted using Tenax sorbent tubes and laboratory analysis by gas chromatography, and grab sampling and in situ analysis also were conducted using a portable gas chromatograph. With the first technique, monocyclic aromatic hydrocarbons appeared as the compounds with the higher mean concentrations. The second technique allowed the systematic analysis of eight chlorinated and aromatic hydrocarbons. Results of comparing both techniques, as well as the additional information obtained with the second technique, are included.

  7. Mathematical modeling of atmospheric fine particle-associated primary organic compound concentrations

    NASA Astrophysics Data System (ADS)

    Rogge, Wolfgang F.; Hildemann, Lynn M.; Mazurek, Monica A.; Cass, Glen R.; Simoneit, Bernd R. T.

    1996-08-01

    An atmospheric transport model has been used to explore the relationship between source emissions and ambient air quality for individual particle phase organic compounds present in primary aerosol source emissions. An inventory of fine particulate organic compound emissions was assembled for the Los Angeles area in the year 1982. Sources characterized included noncatalyst- and catalyst-equipped autos, diesel trucks, paved road dust, tire wear, brake lining dust, meat cooking operations, industrial oil-fired boilers, roofing tar pots, natural gas combustion in residential homes, cigarette smoke, fireplaces burning oak and pine wood, and plant leaf abrasion products. These primary fine particle source emissions were supplied to a computer-based model that simulates atmospheric transport, dispersion, and dry deposition based on the time series of hourly wind observations and mixing depths. Monthly average fine particle organic compound concentrations that would prevail if the primary organic aerosol were transported without chemical reaction were computed for more than 100 organic compounds within an 80 km × 80 km modeling area centered over Los Angeles. The monthly average compound concentrations predicted by the transport model were compared to atmospheric measurements made at monitoring sites within the study area during 1982. The predicted seasonal variation and absolute values of the concentrations of the more stable compounds are found to be in reasonable agreement with the ambient observations. While model predictions for the higher molecular weight polycyclic aromatic hydrocarbons (PAH) are in agreement with ambient observations, lower molecular weight PAH show much higher predicted than measured atmospheric concentrations in the particle phase, indicating atmospheric decay by chemical reactions or evaporation from the particle phase. The atmospheric concentrations of dicarboxylic acids and aromatic polycarboxylic acids greatly exceed the contributions that

  8. Speciation and source identification of organic compounds in PM₁₀ over Seoul, South Korea.

    PubMed

    Choi, Na Rae; Lee, Se Pyo; Lee, Ji Yi; Jung, Chang Hoon; Kim, Yong Pyo

    2016-02-01

    Seventy three individual organic compounds in the atmospheric particulate matter with an aerodynamic diameter of less than or equal to a nominal 10 μm (PM10) over Seoul were identified and quantified from April 2010 to April 2011 using gas chromatography/mass spectrometry (GC/MS). These organic compounds were classified into five groups, n-alkanes, polycyclic aromatic hydrocarbons (PAHs), mono-carboxylic acids, di-carboxylic acids (DCAs), and sugars based on their chemical structures and properties. The organic compounds showed higher seasonal average concentrations from fall to winter than from spring to summer due to source strength, except some organic compounds among mono-carboxylic acids, DCAs, sugars such as undecanoic acid, methylmalonic acid, and fructose. Through qualitative data analysis using seasonal concentration variations and relevant diagnostic parameters, it was found that (1) anthropogenic sources such as combustion of fossil fuel and biomass burning attributed more to the formation of the organic aerosols than biogenic sources, and (2) the ambient level of n-alkanes, PAHs, and some compounds of DCAs and sugars was elevated in winter due to the increased primary emissions and larger transport from outside of the organic compounds in winter.

  9. A Green, Guided-Inquiry Based Electrophilic Aromatic Substitution for the Organic Chemistry Laboratory

    ERIC Educational Resources Information Center

    Eby, Eric; Deal, S. Todd

    2008-01-01

    We developed an alternative electrophilic aromatic substitution reaction for the organic chemistry teaching laboratory. The experiment is an electrophilic iodination reaction of salicylamide, a popular analgesic, using environmentally friendly reagents--sodium iodide and household bleach. Further, we designed the lab as a guided-inquiry…

  10. Hybrid membranes of metal-organic molecule nanocages for aromatic/aliphatic hydrocarbon separation by pervaporation.

    PubMed

    Zhao, Cui; Wang, Naixin; Wang, Lin; Huang, Hongliang; Zhang, Rong; Yang, Fan; Xie, Yabo; Ji, Shulan; Li, Jian-Rong

    2014-11-21

    Hybrid membranes composed of porous metal-organic molecule nanocages as fillers embedded in a hyperbranched polymer (Boltorn W3000) were fabricated, which exhibit excellent pervaporation separation performances towards aromatic/aliphatic hydrocarbons. The unique nature of the molecule-based fillers and their good dispersion and compatibility in/with the polymer are responsible for the good membrane properties.

  11. Acute photo-induced toxicity and toxicokinetics of single compounds and mixtures of polycyclic aromatic hydrocarbons in zebrafish.

    PubMed

    Willis, Alison M; Oris, James T

    2014-09-01

    The present study examined photo-induced toxicity and toxicokinetics for acute exposure to selected polycyclic aromatic hydrocarbons (PAHs) in zebrafish. Photo-enhanced toxicity from co-exposure to ultraviolet (UV) radiation and PAHs enhanced the toxicity and exhibited toxic effects at PAH concentrations orders of magnitude below effects observed in the absence of UV. Because environmental exposure to PAHs is usually in the form of complex mixtures, the present study examined the photo-induced toxicity of both single compounds and mixtures of PAHs. In a sensitive larval life stage of zebrafish, acute photo-induced median lethal concentrations (LC50s) were derived for 4 PAHs (anthracene, pyrene, carbazole, and phenanthrene) to examine the hypothesis that phototoxic (anthracene and pyrene) and nonphototoxic (carbazole and phenanthrene) pathways of mixtures could be predicted from single exposures. Anthracene and pyrene were phototoxic as predicted; however, carbazole exhibited moderate photo-induced toxicity and phenanthrene exhibited weak photo-induced toxicity. The toxicity of each chemical alone was used to compare the toxicity of mixtures in binary, tertiary, and quaternary combinations of these PAHs, and a predictive model for environmental mixtures was generated. The results indicated that the acute toxicity of PAH mixtures was additive in phototoxic scenarios, regardless of the magnitude of photo-enhancement. Based on PAH concentrations found in water and circumstances of high UV dose to aquatic systems, there exists potential risk of photo-induced toxicity to aquatic organisms.

  12. Adsorption of aromatic compounds by carbonaceous adsorbents: a comparative study on granular activated carbon, activated carbon fiber, and carbon nanotubes.

    PubMed

    Zhang, Shujuan; Shao, Ting; Kose, H Selcen; Karanfil, Tanju

    2010-08-15

    Adsorption of three aromatic organic compounds (AOCs) by four types of carbonaceous adsorbents [a granular activated carbon (HD4000), an activated carbon fiber (ACF10), two single-walled carbon nanotubes (SWNT, SWNT-HT), and a multiwalled carbon nanotube (MWNT)] with different structural characteristics but similar surface polarities was examined in aqueous solutions. Isotherm results demonstrated the importance of molecular sieving and micropore effects in the adsorption of AOCs by carbonaceous porous adsorbents. In the absence of the molecular sieving effect, a linear relationship was found between the adsorption capacities of AOCs and the surface areas of adsorbents, independent of the type of adsorbent. On the other hand, the pore volume occupancies of the adsorbents followed the order of ACF10 > HD4000 > SWNT > MWNT, indicating that the availability of adsorption site was related to the pore size distributions of the adsorbents. ACF10 and HD4000 with higher microporous volumes exhibited higher adsorption affinities to low molecular weight AOCs than SWNT and MWNT with higher mesopore and macropore volumes. Due to their larger pore sizes, SWNTs and MWNTs are expected to be more efficient in adsorption of large size molecules. Removal of surface oxygen-containing functional groups from the SWNT enhanced adsorption of AOCs.

  13. Organic compounds near dumpsites in Niagara Falls, New York.

    PubMed

    Elder, V A; Proctor, B L; Hites, R A

    1981-09-01

    Water and sediment samples were taken from sites adjacent to hazardous waste disposal areas in Niagara Falls, New York. The samples were analyzed by gas chromatographic mass spectrometry. The following compounds were identified: chlorobenzenes, chlorotoluenes, polycyclic aromatic hydrocarbon derivatives, cyclohexane derivatives, polychlorinated biphenyls, trichlorophenol and other phenols, benzotrifluorides, mirex and phenothiazine. A large number of benzyl derivatives and unusual fluorinated compounds were also found; they were probably waste by-products of industrial chemical production. The hazardous waste disposal sites were probably the major sources for most of the compounds.

  14. Polarizable Empirical Force Field for Aromatic Compounds Based on the Classical Drude Oscillator

    PubMed Central

    Lopes, Pedro E. M.; Lamoureux, Guillaume; Roux, Benoit; MacKerell, Alexander D.

    2008-01-01

    The polarizable empirical CHARMM force field based on the classical Drude oscillator has been extended to the aromatic compounds benzene and toluene. Parameters were optimized for benzene and then transferred directly to toluene, with parameters for the methyl moiety of toluene taken from the previously published work on the alkanes. Optimization of all parameters was performed against an extensive set of quantum mechanical and experimental data. Ab initio data was used for determination of the electrostatic parameters, the vibrational analysis, and in the optimization of the relative magnitudes of the Lennard-Jones parameters. The absolute values of the Lennard-Jones parameters were determined by comparing computed and experimental heats of vaporization, molecular volumes, free energies of hydration and dielectric constants. The newly developed parameter set was extensively tested against additional experimental data such as vibrational spectra in the condensed phase, diffusion constants, heat capacities at constant pressure and isothermal compressibilities including data as a function of temperature. Moreover, the structure of liquid benzene, liquid toluene and of solutions of each in water were studied. In the case of benzene, the computed and experimental total distribution function were compared, with the developed model shown to be in excellent agreement with experiment. PMID:17388420

  15. Remediation of polycyclic aromatic hydrocarbon compounds in groundwater using poplar trees.

    PubMed

    Widdowson, Mark A; Shearer, Sandra; Andersen, Rikke G; Novak, John T

    2005-03-15

    A seven-year study was conducted to assess the effectiveness of hybrid poplar trees to remediate polycyclic aromatic hydrocarbon (PAH) compounds in soil and groundwater at a creosote-contaminated site. A reduction in the areal extent of the PAH plume was observed in the upper half of the 2-m-thick saturated zone, and PAH concentration levels in the groundwater declined throughout the plume. PAH concentrations began to decline during the period between the third and fourth growing seasons, which coincided with the propagation of the tree roots to the water table region. Remediation was limited to naphthalene and several three-ring PAHs (acenaphthylene and acenaphthene). PAH concentrations in soil and aquifer sediment samples also declined over time; however, levels of four-ring PAHs persisted at the lower depths during the study period. The naphthalene to total PAH concentration ratio in the most contaminated groundwater decreased from >0.90 at the beginning of the second growing season to approximately 0.70 at the end the study. Remediation in the lower region of the saturated zone was limited bythe presence of a 0.3-m-thick layer of creosote present as a dense nonaqueous phase liquid (DNAPL). The nearly steady-state condition of the PAH concentrations observed during the last three years of the study suggests that the effectiveness of the phytoremediation system is limited by the rate of PAH dissolution from the DNAPL source.

  16. Demonstration of the interactions between aromatic compound-loaded lipid nanocapsules and Acinetobacter baumannii bacterial membrane.

    PubMed

    Montagu, A; Joly-Guillou, M-L; Guillet, C; Bejaud, J; Rossines, E; Saulnier, P

    2016-06-15

    Acinetobacter baumannii is an important nosocomial pathogen that is resistant to many commonly-used antibiotics. One strategy for treatment is the use of aromatic compounds (carvacrol, cinnamaldehyde) against A. baumannii. The aim of this study was to determine the interactions between bacteria and lipid nanocapsules (LNCs) over time based on the fluorescence of 3,3'-Dioctadecyloxacarbocyanine Perchlorate-LNCs (DiO-LNCs) and the properties of trypan blue to analyse the physicochemical mechanisms occurring at the level of the biological membrane. The results demonstrated the capacity of carvacrol-loaded LNCs to interact with and penetrate the bacterial membrane in comparison with cinnamaldehyde-loaded LNCs and unloaded LNCs. Modifications of carvacrol after substitution of hydroxyl functional groups by fatty acids demonstrated the crucial role of hydroxyl functions in antibacterial activity. Finally, after contact with the efflux pump inhibitor, carbonylcyanide-3-chlorophenyl hydrazine (CCCP), the results indicated the total synergistic antibacterial effect with Car-LNCs, showing that CCCP is associated with the action mechanism of carvacrol, especially at the level of the efflux pump mechanism.

  17. IRRADIATION METHOD OF CONVERTING ORGANIC COMPOUNDS

    DOEpatents

    Allen, A.O.; Caffrey, J.M. Jr.

    1960-10-11

    A method is given for changing the distribution of organic compounds from that produced by the irradiation of bulk alkane hydrocarbons. This method consists of depositing an alkane hydrocarbon on the surface of a substrate material and irradiating with gamma radiation at a dose rate of more than 100,000 rads. The substrate material may be a metal, metal salts, metal oxides, or carbons having a surface area in excess of 1 m/sup 2//g. The hydrocarbons are deposited in layers of from 0.1 to 10 monolayers on the surfaces of these substrates and irradiated. The product yields are found to vary from those which result from the irradiation of bulk hydrocarbons in that there is an increase in the quantity of branched hydrocarbons.

  18. Volatilization of organic compounds from streams

    USGS Publications Warehouse

    Rathburn, R.E.; Tai, D.Y.

    1982-01-01

    Mass-transfer coefficients for the volatilization of ethylene and propane were correlated with the hydraulic and geometric properties of seven streams, and predictive equations were developed. The equations were evaluated using a normalized root-mean-square error as the criterion of comparison. The two best equations were a two-variable equation containing the energy dissipated per unit mass per unit time and the average depth of flow and a three-variable equation containing the average velocity, the average depth of flow, and the slope of the stream. Procedures for adjusting the ethylene and propane coefficients for other organic compounds were evaluated. These procedures are based on molecular diffusivity, molecular diameter, or molecular weight. Because of limited data, none of these procedures have been extensively verified. Therefore, until additional data become available, it is suggested that the mass-transfer coefficient be assumed to be inversely proportional to the square root of the molecular weight.

  19. Carbon 13 chemical shift tensors in aromatic compounds. 3. Phenanthrene and triphenylene

    SciTech Connect

    Soderquist, A.; Hughes, C.D.; Horton, W.J.; Facelli, J.C.; Grant, D.M.

    1992-04-08

    Measurements of the principal values of the {sup 13}C chemical shift tensor are presented for the three carbons in triphenylene and for three different {alpha} carbons in phenanthrene. The measurements in triphenylene were made in natural abundance samples at room temperature, while the phenanthrene tensors were obtained from selectively labeled compounds (99% {sup 13}C) at low temperatures ({approx} 25 K). The principal values of the shift tensors were oriented in the molecular frame using ab initio LORG calculations. The steric compression at C{sub 4} in phenanthrene and in corresponding positions in triphenylene is manifested in sizable upfield shift in the {sigma} 33 component relative to the corresponding {sigma} 33 values at C{sub 1} and C{sub 9} in phenanthrene. The upfield shift in {sigma} 33 is mainly responsible for the well-known upfield shift of the isotropic chemical shifts of such sterically perturbed carbons. In phenanthrene c{sub 9} exhibits a unique {sigma} 22 value reflecting the greater localization of {pi}-electrons in the c{sub 9}-C{sub 10} bond. This localization of the {pi}-electrons at the C{sub 9}-C{sub 10} bond in the central ring of phenanthrene also corresponds with the most likely ordering of electrons described by the various Kekule structures in phenanthrene. The analysis of the {sup 13}C chemical shieldings of the bridgehead carbons in the triphenylene provides significant experimental information on bonding between rings in polycyclic aromatic compounds. 39 refs., 8 fig., 3 tab.

  20. Biological monitoring of exposure to polycyclic aromatic hydrocarbons by determination of unmetabolized compounds in urine.

    PubMed

    Campo, Laura; Addario, Liliana; Buratti, Marina; Scibetta, Licia; Longhi, Omar; Valla, Carla; Cirla, Piero E; Martinotti, Irene; Foà, Vito; Fustinoni, Silvia

    2006-04-10

    In this paper we evaluated the possibility to assess occupational exposure to polycyclic aromatic hydrocarbons (PAHs) measuring unmetabolized PAHs in urine. With this aim, 24 road paving (RP) workers, exposed to bitumen fumes, and 6 road construction workers (CW), exposed to diesel exhausts, were investigated. Median personal exposure to low boiling PAHs (from naphthalene to pyrene) during the work shift ranged from 0.5 to 369 ng/m(3), with naphthalene as the most abundant compound. Three urine samples were collected for each worker: baseline (after 2 days of vacation), before- and end-shift samples (in the second part of the work week). The following urinary compounds were measured by headspace-solid phase microextraction GC/MS: naphthalene (U-NAP), acenaphthylene (U-ACY), acenaphthene (U-ACE), fluorene (U-FLE), phenanthrene (U-PHE), anthracene (U-ANT), fluoranthene (U-FLU), pyrene (U-PYR). Urinary PAHs were detected in almost all samples. Median levels for U-NAP, U-PHE, U-PYR and U-FLE in end-shift samples were 82, 48, 54 and 21 ng/L in RP and 69, 14, 24 and 15 ng/L in CW, respectively. Significant differences in the levels of U-PHE, U-FLU and U-PYR were found between RP and CW (p<0.05). Moreover in RP samples the urinary excretion of most analytes increased during the work shift (p<0.05). These results suggest that urinary PAHs may be useful biomarkers of occupational exposure.

  1. Extraction of organic compounds from solid samples

    SciTech Connect

    Junk, G.A.; Richard, J.J.

    1986-04-01

    Pyridine, benzene, cyclohexane, methylene chloride, dimethyl sulfoxide, dimethylformamide, and n-methylpyrrolidone have been compared for the extraction of polycyclic organic materials (POMs) from urban air, diesel, and stack particulate samples. Both sonic and Soxhlet techniques have been examined for both natural environmental particulates and particulates spiked with selected POMs. The extraction results vary for different polycyclic compounds adsorbed on different solid matrices, so no single solvent or extraction technique could be unambiguously recommended. However, comparative average results for 14 compounds spiked onto fly ash at 0.1, 0.25, and 1.0 ..mu..g/g showed pyridine to have 1.5 times more extraction efficiency than benzene. These and other reported results suggest that pyridine deserves more attention as an extractant for particulate samples. In separate tests, recoveries of POMs from fly ash were not improved by deactivation with aqueous solutions of ammonium hydroxide, thiocyanate and carbonate, and sodium nitrite prior to the extraction. 39 references, 5 tables.

  2. Synthesis and Exploration of Ladder-Structured Large Aromatic Dianhydrides as Organic Cathodes for Rechargeable Lithium-Ion Batteries.

    PubMed

    Xie, Jian; Chen, Wangqiao; Wang, Zilong; Jie, Kenneth Choo Wei; Liu, Ming; Zhang, Qichun

    2017-02-21

    Compared to anode materials in Li-ion batteries, the research on cathode materials is far behind, and their capacities are much smaller. Thus, in order to address these issues, we believe that organic conjugated materials could be a solution. In this study, we synthesized two non-polymeric dianhydrides with large aromatic structures: NDA-4N (naphthalenetetracarboxylic dianhydride with four nitrogen atoms) and PDA-4N (perylenetetracarboxylic dianhydride with four nitrogen atoms). Their electrochemical properties have been investigated between 2.0 and 3.9 V (vs. Li(+) /Li). Benefiting from multi-electron reactions, NDA-4N and PDA-4N could reversibly achieve 79.7 % and 92.3 %, respectively, of their theoretical capacity. Further cycling reveals that the organic compound with a relatively larger aromatic building block could achieve a better stability, as an obvious 36.5 % improvement of the capacity retention was obtained when the backbone was switched from naphthalene to perylene. This study proposes an opportunity to attain promising small-molecule-based cathode materials through tailoring organic structures.

  3. Identification of nonmethane organic compound emissions from grassland vegetation.

    SciTech Connect

    Fukui, Y.; Doskey, P. V.; Environmental Research; NASA Ames Research Center

    2000-01-01

    Emissions of nonmethane organic compounds (NMOCs) from grassland vegetation were collected in Summa(reg.sign) passivated stainless-steel canisters with a static enclosure technique and were analyzed by high-resolution gas chromatography with flame ionization and ion trap mass spectrometric detectors. Approximately 40 NMOCs with 6-10 carbon atoms were observed in samples analyzed by high-resolution gas chromatography with the flame ionization detector. Nineteen NMOCs in this molecular weight range (6 aliphatic oxygenates; 1 aromatic hydrocarbon; and 4 acyclic, 5 monocyclic, and 3 bicyclic monoterpenoids) were identified by ion trap mass spectrometry. Mass spectrometry was particularly useful for identifying myrcene and cis-3-hexenylacetate, which coeluted on a fused-silica capillary column coated with a 1-{mu}m-thick film of polydimethylsiloxane. An evaluation of the reactivity of the grassland emissions revealed that the aliphatic oxygenates have lifetimes of a few hours with respect to oxidation by OH and O{sub 3} in the atmosphere. This value is similar to the lifetimes of the bicyclic monoterpenoids. The expected lifetimes of the monoterpenoids with respect to oxidation by NO{sub 3} are only several minutes.

  4. Aromatizing olefin metathesis by ligand isolation inside a metal-organic framework.

    PubMed

    Vermeulen, Nicolaas A; Karagiaridi, Olga; Sarjeant, Amy A; Stern, Charlotte L; Hupp, Joseph T; Farha, Omar K; Stoddart, J Fraser

    2013-10-09

    The aromatizing ring-closing metathesis has been shown to take place inside an extended porous framework. Employing a combination of solvent-assisted linker exchange and postsynthesis modification using olefin metathesis, the noninterpenetrated SALEM-14 was formed and converted catalytically into PAH-MOF-1 with polycyclic aromatic hydrocarbon (PAH) pillars. The metal-organic framework in SALEM-14 prevents "intermolecular" olefin metathesis from occurring between the pillars in the presence of the first generation Hoveyda-Grubbs catalyst, while favoring the production of a PAH, which can be released from the framework under acidic conditions in dimethylsulfoxide.

  5. Tropospheric volatile organic compounds in China.

    PubMed

    Guo, H; Ling, Z H; Cheng, H R; Simpson, I J; Lyu, X P; Wang, X M; Shao, M; Lu, H X; Ayoko, G; Zhang, Y L; Saunders, S M; Lam, S H M; Wang, J L; Blake, D R

    2017-01-01

    Photochemical smog, characterized by high concentrations of ozone (O3) and fine particles (PM2.5) in the atmosphere, has become one of the top environmental concerns in China. Volatile organic compounds (VOCs), one of the key precursors of O3 and secondary organic aerosol (SOA) (an important component of PM2.5), have a critical influence on atmospheric chemistry and subsequently affect regional and global climate. Thus, VOCs have been extensively studied in many cities and regions in China, especially in the North China Plain, the Yangtze River Delta and the Pearl River Delta regions where photochemical smog pollution has become increasingly worse over recent decades. This paper reviews the main studies conducted in China on the characteristics and sources of VOCs, their relationship with O3 and SOA, and their removal technology. This paper also provides an integrated literature review on the formulation and implementation of effective control strategies of VOCs and photochemical smog, as well as suggestions for future directions of VOCs study in China.

  6. Organic compounds in meteorites and their origins

    NASA Technical Reports Server (NTRS)

    Hayatsu, R.; Anders, E.

    1981-01-01

    The current investigation represents an extensively updated version of a review conducted by Anders et al. (1973). The investigation takes into account the literature through mid-1980. It is pointed out that Type 1 carbonaceous chondrites (C1) contain 6% of their cosmic complement of carbon, mainly in the form of organic matter. Most authors now agree that this material represents primitive prebiotic matter. The principal questions remaining are what abiotic processes formed the organic matter, and to what extent these processes took place in locales other than the solar nebula, such as interstellar clouds or meteorite parent bodes. The problem is approached in three stages. It is attempted to reconstruct the physical conditions during condensation from the clues contained in the inorganic matrix of the meteorite. The condensation behavior of carbon under these conditions is determined on the basis of thermodynamic calculations. Model experiments on the condensation of carbon are performed, and the synthesized compounds are compared with those actually found in meteorites.

  7. Linear and nonlinear optical properties of new materials based on DNA-CTMA and aromatic compounds (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Lazar, Cosmina Andreea; Kajzar, François; Rau, Ileana; Puntus, Lada N.; Manea, Ana-Maria

    2016-10-01

    In order to find eco-friendly materials for different applications an important research effort was devoted to the materials science in the last decade. A particular attention attracted the deoxyribonucleic acid (DNA). The interest is due to its versatility, biodegradability, abundance and their origin from renewable sources. DNA based new materials, functionalized with hexadecyltrimethylammonium chloride (CTMA) and aromatic compounds were prepared. Solutions with two different concentrations of aromatic compounds were obtained in butanol. The obtained, new complexes were processed into good optical quality thin films by spin coating method. Films were deposited on glass substrates and characterized for their spectroscopic, linear and nonlinear optical properties. The third-order nonlinear optical (NLO) properties of thin films were determined by the optical third-harmonic generation technique at 1 064.2 nm fundamental wavelength. The obtained materials, with improved fluorescence efficiency, present a potential interest for application in photonics.

  8. Diurnal variability of polycyclic aromatic compound (PAC) concentrations: Relationship with meteorological conditions and inferred sources

    NASA Astrophysics Data System (ADS)

    Alam, Mohammed S.; Keyte, Ian J.; Yin, Jianxin; Stark, Christopher; Jones, Alan M.; Harrison, Roy M.

    2015-12-01

    Polycyclic aromatic hydrocarbons (PAH) and their nitro and oxy derivatives have been sampled every three hours over one week in winter at two sites in Birmingham UK. One site is heavily influenced by road traffic and is close to residential dwellings, while the other site is a background urban location at some distance from both sources of emission. The time series of concentrations has been examined along with the ratio of concentrations between the two sampling sites. A comparison of averaged diurnal profiles has shown different patterns of behaviour which has been investigated through calculating ratios of concentration at 18:00-21:00 h relative to that at 06:00-09:00 h. This allows identification of those compounds with a strong contribution to a traffic-related maximum at 06:00-09:00 h which are predominantly the low molecular weight PAHs, together with a substantial group of quinones and nitro-PAHs. Changes in partitioning between vapour and particulate forms are unlikely to influence the ratio as the mean temperature at both times was almost identical. Most compounds show an appreciable increase in concentrations in the evening which is attributed to residential heating emissions. Compounds dominated by this source show high ratios of 18:00-21:00 concentrations relative to 06:00-09:00 concentrations and include higher molecular weight PAH and a substantial group of both quinones and nitro-PAH. The behaviour of retene, normally taken as an indicator of biomass burning, is suggestive of wood smoke only being one contributor to the evening peak in PAH and their derivatives, with coal combustion presumably being the other main contributor. Variations of PAH concentrations with wind speed show a dilution behaviour consistent with other primary pollutants, and high concentrations of a range of air pollutants were observed in an episode of low temperatures and low wind speeds towards the end of the overall sampling period consistent with poor local dispersion

  9. Petroleum alteration by thermochemical sulfate reduction - A comprehensive molecular study of aromatic hydrocarbons and polar compounds

    NASA Astrophysics Data System (ADS)

    Walters, Clifford C.; Wang, Frank C.; Qian, Kuangnan; Wu, Chunping; Mennito, Anthony S.; Wei, Zhibin

    2015-03-01

    Thermochemical sulfate reduction (TSR) alters petroleum composition as it proceeds towards the complete oxidation of hydrocarbons to CO2. The effects of TSR on the molecular and isotopic composition of volatile species are well known; however, the non-volatile higher molecular weight aromatic and polar species have not been well documented. To address this deficiency, a suite of onshore Gulf coast oils and condensates generated from and accumulating in Smackover carbonates was assembled to include samples that experienced varying levels of TSR alteration and in reservoir thermal cracking. The entire molecular composition of aromatic hydrocarbons and NSO species were characterized and semi-quantified using comprehensive GC × GC (FID and CSD) and APPI-FTICR-MS. The concentration of thiadiamondoids is a reliable indicator of the extent of TSR alteration. Once generated by TSR, thiadiamondoids remain thermally stable in all but the most extreme reservoir temperatures (>180 °C). Hydrocarbon concentrations and distributions are influenced by thermal cracking and TSR. With increasing TSR alteration, oils become enriched in monoaromatic hydrocarbons and the distribution of high molecular weight aromatic hydrocarbons shifts towards more condensed species with a decrease in the number of alkyl carbons. Organosulfur compounds are created by the TSR process. In addition to the increase in benzothiophenes and dibenzothiophenes noted in previous studies, TSR generates condensed species containing one or more sulfur atoms that likely are composed of a single or multiple thiophenic cores. We hypothesize that these species are generated from the partial oxidation of PAHs and dealkylation reactions, followed by sulfur incorporation and condensation reactions. The organosulfur species remaining in the TSR altered oils are "proto-solid bitumen" moieties that upon further condensation, oxidation or sulfur incorporation result in highly sulfur enriched solid bitumen, which is

  10. Anthropogenic and biogenic organic compounds in summertime fine aerosols (PM2.5) in Beijing, China

    NASA Astrophysics Data System (ADS)

    Yang, Fan; Kawamura, Kimitaka; Chen, Jing; Ho, Kinfai; Lee, Shuncheng; Gao, Yuan; Cui, Long; Wang, Tieguan; Fu, Pingqing

    2016-01-01

    Ambient fine aerosol samples (PM2.5) were collected at an urban site (PKU) in Beijing and its upwind suburban site (Yufa) during the CAREBEIJING-2007 field campaign. Organic molecular compositions of the PM2.5 samples were studied for seven organic compound classes (sugars, lignin/resin acids, hydroxy-/polyacids, aromatic acids, biogenic SOA tracers, fatty acids and phthalates) using capillary GC/MS to better understand the characteristics and sources of organic aerosol pollution in Beijing. More than 60 individual organic species were detected in PM2.5 and were grouped into different compound classes based on their functional groups. Concentrations of total quantified organics at Yufa (469-1410 ng m-3, average 1050 ng m-3) were slightly higher than those at PKU (523-1390 ng m-3, 900 ng m-3). At both sites, phthalates were found as the most abundant compound class. Using a tracer-based method, the contributions of the biogenic secondary organic carbon (SOC) to organic carbon (OC) were 3.1% at PKU and 5.5% at Yufa, among which isoprene-SOC was the dominant contributor. In addition, most of the measured organic compounds were higher at Yufa than those at PKU, indicating a more serious pollution in its upwind region than in urban Beijing.

  11. Bioremediation of PAH-contamined soils: Consequences on formation and degradation of polar-polycyclic aromatic compounds and microbial community abundance.

    PubMed

    Biache, Coralie; Ouali, Salma; Cébron, Aurélie; Lorgeoux, Catherine; Colombano, Stéfan; Faure, Pierre

    2017-05-05

    A bioslurry batch experiment was carried out over five months on three polycyclic aromatic compound (PAC) contaminated soils to study the PAC (PAH and polar-PAC) behavior during soil incubation and to evaluate the impact of PAC contamination on the abundance of microbial communities and functional PAH-degrading populations. Organic matter characteristics and reactivity, assessed through solvent extractable organic matter and PAC contents, and soil organic matter mineralization were monitored during 5 months. Total bacteria and fungi, and PAH-ring hydroxylating dioxygenase genes were quantified. Results showed that PAHs and polar-PACs were degraded with different degradation dynamics. Differences in degradation rates were observed among the three soils depending on PAH distribution and availability. Overall, low molecular weight compounds were preferentially degraded. Degradation selectivity between isomers and structurally similar compounds was observed which could be used to check the efficiency of bioremediation processes. Bacterial communities were dominant over fungi and were most likely responsible for PAC degradation. Abundance of PAH-degrading bacteria increased during incubations, but their proportion in the bacterial communities tended to decrease. The accumulation of some oxygenated-PACs during the bioslurry experiment underlines the necessity to monitor these compounds during application of remediation treatment on PAH contaminated soils.

  12. Tritium labeling of organic compounds deposited on porous structures

    DOEpatents

    Ehrenkaufer, Richard L. E.; Wolf, Alfred P.; Hembree, Wylie C.

    1979-01-01

    An improved process for labeling organic compounds with tritium is carried out by depositing the selected compound on the extensive surface of a porous structure such as a membrane filter and exposing the membrane containing the compound to tritium gas activated by the microwave discharge technique. The labeled compound is then recovered from the porous structure.

  13. Validated analytical strategy for the determination of polycyclic aromatic compounds in marine sediments by liquid chromatography coupled with diode-array detection and mass spectrometry.

    PubMed

    González-Piñuela, Cristina; Alonso-Salces, Rosa M; Andrés, Ana; Ortiz, Inmaculada; Viguri, Javier R

    2006-10-06

    The aim of this work was to optimise and validate the experimental conditions for the analysis of 20 polycyclic aromatic compounds (PACs) [19 polycyclic aromatic hydrocarbons (PAHs) and dibenzothiophene as polycyclic aromatic sulphur heterocycle (PASH)] in marine sediments by reversed-phase high-performance liquid chromatography (LC) coupled to photodiode array detection (DAD) and to mass spectrometry (MS). The LC-MS interface used was atmospheric pressure chemical ionization (APCI) in the positive ion mode. The operational parameters of the APCI interface and MS detection, such as organic modifier, fragmentation voltage, gain, vaporizer temperature, corona current, capillary voltage, drying gas (N2) and nebulizer pressure, were studied. The sediments were subjected to microwave-assisted solvent extraction (MAE) and clean-up by solid-phase extraction (SPE). The relevance of the selected PACs lies in the fact that 16 PACs are classified by the US Environmental Protection Agency as priority pollutants; 17 PACs are detected in the Prestige oil spill; and 8 PACs are included in the priority substance list of the EU water policy. Recoveries from 47% to 102% were obtained for SRM 1944 certified reference sediment. The limits of quantitation were lower than 100 ngg(-1) dry weight for most PACs, and good precision was achieved.

  14. Quantitative prediction of solvation free energy in octanol of organic compounds.

    PubMed

    Delgado, Eduardo J; Jaña, Gonzalo A

    2009-03-01

    The free energy of solvation, DeltaGS0, in octanol of organic compounds is quantitatively predicted from the molecular structure. The model, involving only three molecular descriptors, is obtained by multiple linear regression analysis from a data set of 147 compounds containing diverse organic functions, namely, halogenated and non-halogenated alkanes, alkenes, alkynes, aromatics, alcohols, aldehydes, ketones, amines, ethers and esters; covering a DeltaGS0 range from about -50 to 0 kJ.mol(-1). The model predicts the free energy of solvation with a squared correlation coefficient of 0.93 and a standard deviation, 2.4 kJ.mol(-1), just marginally larger than the generally accepted value of experimental uncertainty. The involved molecular descriptors have definite physical meaning corresponding to the different intermolecular interactions occurring in the bulk liquid phase. The model is validated with an external set of 36 compounds not included in the training set.

  15. Determination of organic compounds leached from municipal incinerator fly ash by water at different pH levels

    SciTech Connect

    Karasek, F.W.; Charbonneau, G.M.; Reuel, G.J.; Tong, H.Y.

    1987-04-01

    This study concerns the possibility of organic compounds entering the environment through the leaching of municipal incinerator fly ash with water. A Soxhlet extraction of fly ash with water, followed by a benzene/water solvent extraction was used to isolate organic compounds. The pH of the extracting liquid was varied (pH 4, 7, 10) and both the type and amount of compounds extracted differed. Many organic compounds including polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans, polycyclic aromatic compounds, phenols, and hydrocarbons were found in the water extracts. Gas chromatography/flame ionization detection, gas chromatography/electron capture detection, and gas chromatography/mass spectrometry using electron impact, positive and negative ion chemical ionization techniques were used for compound identification and quantitation.

  16. Enhancing muconic acid production from glucose and lignin-derived aromatic compounds via increased protocatechuate decarboxylase activity

    SciTech Connect

    Johnson, Christopher W.; Salvachua, Davinia; Khanna, Payal; Smith, Holly; Peterson, Darren J.; Beckham, Gregg T.

    2016-04-22

    The conversion of biomass-derived sugars and aromatic molecules to cis,cis-muconic acid (referred to hereafter as muconic acid or muconate) has been of recent interest owing to its facile conversion to adipic acid, an important commodity chemical. Metabolic routes to produce muconate from both sugars and many lignin-derived aromatic compounds require the use of a decarboxylase to convert protocatechuate (PCA, 3,4-dihydroxybenzoate) to catechol (1,2-dihydroxybenzene), two central aromatic intermediates in this pathway. Several studies have identified the PCA decarboxylase as a metabolic bottleneck, causing an accumulation of PCA that subsequently reduces muconate production. A recent study showed that activity of the PCA decarboxylase is enhanced by co-expression of two genetically associated proteins, one of which likely produces a flavin-derived cofactor utilized by the decarboxylase. Using entirely genome-integrated gene expression, we have engineered Pseudomonas putida KT2440-derived strains to produce muconate from either aromatic molecules or sugars and demonstrate in both cases that co-expression of these decarboxylase associated proteins reduces PCA accumulation and enhances muconate production relative to strains expressing the PCA decarboxylase alone. In bioreactor experiments, co-expression increased the specific productivity (mg/g cells/h) of muconate from the aromatic lignin monomer p-coumarate by 50% and resulted in a titer of >15 g/L. In strains engineered to produce muconate from glucose, co-expression more than tripled the titer, yield, productivity, and specific productivity, with the best strain producing 4.92+/-0.48 g/L muconate. Furthermore, this study demonstrates that overcoming the PCA decarboxylase bottleneck can increase muconate yields from biomass-derived sugars and aromatic molecules in industrially relevant strains and cultivation conditions.

  17. Enhancing muconic acid production from glucose and lignin-derived aromatic compounds via increased protocatechuate decarboxylase activity

    DOE PAGES

    Johnson, Christopher W.; Salvachua, Davinia; Khanna, Payal; ...

    2016-04-22

    The conversion of biomass-derived sugars and aromatic molecules to cis,cis-muconic acid (referred to hereafter as muconic acid or muconate) has been of recent interest owing to its facile conversion to adipic acid, an important commodity chemical. Metabolic routes to produce muconate from both sugars and many lignin-derived aromatic compounds require the use of a decarboxylase to convert protocatechuate (PCA, 3,4-dihydroxybenzoate) to catechol (1,2-dihydroxybenzene), two central aromatic intermediates in this pathway. Several studies have identified the PCA decarboxylase as a metabolic bottleneck, causing an accumulation of PCA that subsequently reduces muconate production. A recent study showed that activity of the PCAmore » decarboxylase is enhanced by co-expression of two genetically associated proteins, one of which likely produces a flavin-derived cofactor utilized by the decarboxylase. Using entirely genome-integrated gene expression, we have engineered Pseudomonas putida KT2440-derived strains to produce muconate from either aromatic molecules or sugars and demonstrate in both cases that co-expression of these decarboxylase associated proteins reduces PCA accumulation and enhances muconate production relative to strains expressing the PCA decarboxylase alone. In bioreactor experiments, co-expression increased the specific productivity (mg/g cells/h) of muconate from the aromatic lignin monomer p-coumarate by 50% and resulted in a titer of >15 g/L. In strains engineered to produce muconate from glucose, co-expression more than tripled the titer, yield, productivity, and specific productivity, with the best strain producing 4.92+/-0.48 g/L muconate. Furthermore, this study demonstrates that overcoming the PCA decarboxylase bottleneck can increase muconate yields from biomass-derived sugars and aromatic molecules in industrially relevant strains and cultivation conditions.« less

  18. Oil sands development contributes polycyclic aromatic compounds to the Athabasca River and its tributaries

    PubMed Central

    Kelly, Erin N.; Short, Jeffrey W.; Schindler, David W.; Hodson, Peter V.; Ma, Mingsheng; Kwan, Alvin K.; Fortin, Barbra L.

    2009-01-01

    For over a decade, the contribution of oil sands mining and processing to the pollution of the Athabasca River has been controversial. We show that the oil sands development is a greater source of contamination than previously realized. In 2008, within 50 km of oil sands upgrading facilities, the loading to the snowpack of airborne particulates was 11,400 T over 4 months and included 391 kg of polycyclic aromatic compounds (PAC), equivalent to 600 T of bitumen, while 168 kg of dissolved PAC was also deposited. Dissolved PAC concentrations in tributaries to the Athabasca increased from 0.009 μg/L upstream of oil sands development to 0.023 μg/L in winter and to 0.202 μg/L in summer downstream. In the Athabasca, dissolved PAC concentrations were mostly <0.025 μg/L in winter and 0.030 μg/L in summer, except near oil sands upgrading facilities and tailings ponds in winter (0.031–0.083 μg/L) and downstream of new development in summer (0.063–0.135 μg/L). In the Athabasca and its tributaries, development within the past 2 years was related to elevated dissolved PAC concentrations that were likely toxic to fish embryos. In melted snow, dissolved PAC concentrations were up to 4.8 μg/L, thus, spring snowmelt and washout during rain events are important unknowns. These results indicate that major changes are needed to the way that environmental impacts of oil sands development are monitored and managed. PMID:19995964

  19. Paternò-Büchi reaction between aromatic carbonyl compounds and 1-(3-furyl)alkanols.

    PubMed

    D'Auria, Maurizio; Emanuele, Lucia; Racioppi, Rocco; Valente, Anna

    2008-01-01

    The photochemical reaction between aromatic carbonyl compounds and 3-furylmethanol derivatives occurs with high regioselectivity. In most of the experiments formation of oxetanes occurs at the hydroxyalkylated double bond. With chiral 1-(3-furyl)alkanols the reaction occurs with good-high stereoselectivity. In the case of 1-(3-furyl)-benzyl alcohol the stereoselectivity can be explained on the basis of the conformers of the reagent, assuming the formation of a complex between the carbonyl compound and the hydroxyl group.

  20. BASIC CHEMICAL RESEARCH PROGRAM. ELECTRICAL PROPERTIES OF ORGANIC COMPOUNDS

    DTIC Science & Technology

    BENZENE, *CYANIDES, *HYDROXIDES, *ORGANIC COMPOUNDS, ACETYLENES, ALKYL RADICALS, AMIDES, ANILINES , BENZALDEHYDES, CHEMICAL REACTIONS , CONDENSATION... REACTIONS , ELECTRICAL CONDUCTIVITY, MATERIALS, MEASUREMENT, MONOCYCLIC COMPOUNDS, PHENOLS, PHENYL RADICALS, QUINONES, SOLID STATE PHYSICS, SYNTHESIS.

  1. Breath measurements as volatile organic compound biomarkers.

    PubMed Central

    Wallace, L; Buckley, T; Pellizzari, E; Gordon, S

    1996-01-01

    A brief review of the uses of breath analysis in studies of environmental exposure to volatile organic compounds (VOCs) is provided. The U.S. Environmental Protection Agency's large-scale Total Exposure Assessment Methodology Studies have measured concentrations of 32 target VOCs in the exhaled breath of about 800 residents of various U.S. cities. Since the previous 12-hr integrated personal air exposures to the same chemicals were also measured, the relation between exposure and body burden is illuminated. Another major use of the breath measurements has been to detect unmeasured pathways of exposure; the major impact of active smoking on exposure to benzene and styrene was detected in this way. Following the earlier field studies, a series of chamber studies have provided estimates of several important physiological parameters. Among these are the fraction, f, of the inhaled chemical that is exhaled under steady-state conditions and the residence times. tau i in several body compartments, which may be associated with the blood (or liver), organs, muscle, and fat. Most of the targeted VOCs appear to have similar residence times of a few minutes, 30 min, several hours, and several days in the respective tissue groups. Knowledge of these parameters can be helpful in estimating body burden from exposure or vice versa and in planning environmental studies, particularly in setting times to monitor breath in studies of the variation with time of body burden. Improvements in breath methods have made it possible to study short-term peak exposure situations such as filling a gas tank or taking a shower in contaminated water. PMID:8933027

  2. Breath measurements as volatile organic compound biomarkers.

    PubMed

    Wallace, L; Buckley, T; Pellizzari, E; Gordon, S

    1996-10-01

    A brief review of the uses of breath analysis in studies of environmental exposure to volatile organic compounds (VOCs) is provided. The U.S. Environmental Protection Agency's large-scale Total Exposure Assessment Methodology Studies have measured concentrations of 32 target VOCs in the exhaled breath of about 800 residents of various U.S. cities. Since the previous 12-hr integrated personal air exposures to the same chemicals were also measured, the relation between exposure and body burden is illuminated. Another major use of the breath measurements has been to detect unmeasured pathways of exposure; the major impact of active smoking on exposure to benzene and styrene was detected in this way. Following the earlier field studies, a series of chamber studies have provided estimates of several important physiological parameters. Among these are the fraction, f, of the inhaled chemical that is exhaled under steady-state conditions and the residence times. tau i in several body compartments, which may be associated with the blood (or liver), organs, muscle, and fat. Most of the targeted VOCs appear to have similar residence times of a few minutes, 30 min, several hours, and several days in the respective tissue groups. Knowledge of these parameters can be helpful in estimating body burden from exposure or vice versa and in planning environmental studies, particularly in setting times to monitor breath in studies of the variation with time of body burden. Improvements in breath methods have made it possible to study short-term peak exposure situations such as filling a gas tank or taking a shower in contaminated water.

  3. Mobilization and Transport of Organic Compounds from Reservoir Rock and Caprock in Geological Carbon Sequestration Sites

    SciTech Connect

    Zhong, Lirong; Cantrell, Kirk J.; Mitroshkov, Alexandre V.; Shewell, Jesse L.

    2014-05-06

    Supercritical CO2 (scCO2) is an excellent solvent for organic compounds, including benzene, toluene, ethyl-benzene, and xylene (BTEX), phenols, and polycyclic aromatic hydrocarbons (PAHs). Monitoring results from geological carbon sequestration (GCS) field tests has shown that organic compounds are mobilized following CO2 injection. Such results have raised concerns regarding the potential for groundwater contamination by toxic organic compounds mobilized during GCS. Knowledge of the mobilization mechanism of organic compounds and their transport and fate in the subsurface is essential for assessing risks associated with GCS. Extraction tests using scCO2 and methylene chloride (CH2Cl2) were conducted to study the mobilization of volatile organic compounds (VOCs, including BTEX), the PAH naphthalene, and n-alkanes (n-C20 – n-C30) by scCO2 from representative reservoir rock and caprock obtained from depleted oil reservoirs and coal from an enhanced coal-bed methane recovery site. More VOCs and naphthalene were extractable by scCO2 compared to the CH2Cl2 extractions, while scCO2 extractable alkane concentrations were much lower than concentrations extractable by CH2Cl2. In addition, dry scCO2 was found to extract more VOCs than water saturated scCO2, but water saturated scCO2 mobilized more naphthalene than dry scCO2. In sand column experiments, moisture content was found to have an important influence on the transport of the organic compounds. In dry sand columns the majority of the compounds were retained in the column except benzene and toluene. In wet sand columns the mobility of the BTEX was much higher than that of naphthalene. Based upon results determined for the reservoir rock, caprock, and coal samples studied here, the risk to aquifers from contamination by organic compounds appears to be relatively low; however, further work is necessary to fully evaluate risks from depleted oil reservoirs.

  4. Volatile organic compound remedial action project

    SciTech Connect

    1991-12-01

    This Environmental Assessment (EA) reviews a proposed project that is planned to reduce the levels of volatile organic compound (VOC) contaminants present in the Mound domestic water supply. The potable and industrial process water supply for Mound is presently obtained from a shallow aquifer via on-site production wells. The present levels of VOCs in the water supply drawn from the on-site wells are below the maximum contaminant levels (MCLs) permissible for drinking water under Safe Drinking Water Act (SDWA; 40 CFR 141); however, Mound has determined that remedial measures should be taken to further reduce the VOC levels. The proposed project action is the reduction of the VOC levels in the water supply using packed tower aeration (PTA). This document is intended to satisfy the requirements of the National Environmental Policy Act (NEPA) of 1969 and associated Council on Environmental Quality regulations (40 CFR parts 1500 through 1508) as implemented through U.S. Department of Energy (DOE) Order 5440.1D and supporting DOE NEPA Guidelines (52 FR 47662), as amended (54 FR 12474; 55 FR 37174), and as modified by the Secretary of Energy Notice (SEN) 15-90 and associated guidance. As required, this EA provides sufficient information on the probable environmental impacts of the proposed action and alternatives to support a DOE decision either to prepare an Environmental Impact Statement (EIS) or issue a Finding of No Significant Impact (FONSI).

  5. Volatile Organic Compound Emissions by Agricultural Crops

    NASA Astrophysics Data System (ADS)

    Ormeno, E.; Farres, S.; Gentner, D.; Park, J.; McKay, M.; Karlik, J.; Goldstein, A.

    2008-12-01

    Biogenic Volatile Organic Compounds (BVOCs) participate in ozone and aerosol formation, and comprise a substantial fraction of reactive VOC emission inventories. In the agriculturally intensive Central Valley of California, emissions from crops may substantially influence regional air quality, but emission potentials have not been extensively studied with advanced instrumentation for many important crops. Because crop emissions may vary according to the species, and California emission inventories are constructed via a bottom-up approach, a better knowledge of the emission rate at the species-specific level is critical for reducing uncertainties in emission inventories and evaluating emission model performance. In the present study we identified and quantified the BVOCs released by dominant agricultural crops in California. A screening study to investigate both volatile and semivolatile BVOC fractions (oxygenated VOCs, isoprene, monoterepenes, sesquiterpenes, etc.) was performed for 25 crop species (at least 3 replicates plants each), including branch enclosures of woody species (e.g. peach, mandarin, grape, pistachio) and whole plant enclosures for herbaceous species (e.g. onion, alfalfa, carrot), through a dynamic cuvette system with detection by PTRMS, in-situ GCMS/FID, and collection on carbon-based adsorbents followed by extraction and GCMS analysis. Emission data obtained in this study will allow inclusion of these crops in BVOC emission inventories and air quality simulations.

  6. Soil amino compound and carbohydrate contents influenced by organic amendments

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Amino compounds (i. e. amino acids and sugars), and carbohydrates are labile organic components and contribute to the improvement of soil fertility and quality. Animal manure and other organic soil amendments are rich in both amino compounds and carbohydrates, hence organic soil amendments might af...

  7. Gondola-shaped tetra-rhenium metallacycles modified evanescent wave infrared chemical sensors for selective determination of volatile organic compounds.

    PubMed

    Huang, Genin Gary; Lee, Chung-Jay; Tsai, Bo-Chan; Yang, Jyisy; Sathiyendiran, Malaichamy; Lu, Kuang-Lieh

    2011-07-15

    Water-stable and cavity-contained rhenium metallacycles were synthesized, and their ability to selectively interact with volatile organic compounds (VOCs) systematically studied using attenuated total reflection infrared (ATR-IR) spectroscopy. Integrating the unique properties of rhenium metallacycles into optical sensing technologies significantly improves selectivity in detecting aromatic compounds. To explore the interaction of rhenium metallacycles with VOCs, the surface of ATR sensing elements was modified with the synthesized rhenium metallacycles and used to detect VOCs. The results indicate that rhenium metallacycles have crown ether-like recognition sites, which can selectively interact with aromatic compounds, especially those bearing polar functional groups. The IR absorption bands of rhenium metallacycles shift significantly upon adsorption of aromatic VOCs, revealing a strong interaction between the tetra-rhenium metallacycles and guest aromatic compounds. Optimizing the thickness of the metallacycles coated on the surface of the sensing element led to rapid response in detection. The dynamic range of response was generally up to 30 mg/L with detection limits ca. 30 μg/L. Further studies of the effect of interferences indicate that recovery can be higher than 95% for most of the compounds tested. The results on the flow-cell device indicated that the performances were similar to a static detection system but the detection of VOCs can be largely simplified.

  8. Photocatalytic transformations of organic sulfur compounds and H2S

    NASA Astrophysics Data System (ADS)

    Vorontsov, A. V.

    2008-10-01

    Modern views on the products, pathways and kinetic features of liquid- and gas-phase photocatalytic reactions of sulfur compounds in the presence of heterogeneous and homogeneous photocatalysts are generalised. Attention is focussed on the aliphatic and aromatic reduced sulfur compounds and pesticides. The reaction rate in the liquid and gas phases are analysed as function of solution pH, temperature, catalyst content, substrate concentration, solvent type, air moisture and added oxidants. Photocatalyst deactivation and the ways for recovery of its activity are considered.

  9. The Geoglobus acetivorans Genome: Fe(III) Reduction, Acetate Utilization, Autotrophic Growth, and Degradation of Aromatic Compounds in a Hyperthermophilic Archaeon

    PubMed Central

    Mardanov, Andrey V.; Slododkina, Galina B.; Slobodkin, Alexander I.; Beletsky, Alexey V.; Gavrilov, Sergey N.; Kublanov, Ilya V.; Bonch-Osmolovskaya, Elizaveta A.; Skryabin, Konstantin G.

    2014-01-01

    Geoglobus acetivorans is a hyperthermophilic anaerobic euryarchaeon of the order Archaeoglobales isolated from deep-sea hydrothermal vents. A unique physiological feature of the members of the genus Geoglobus is their obligate dependence on Fe(III) reduction, which plays an important role in the geochemistry of hydrothermal systems. The features of this organism and its complete 1,860,815-bp genome sequence are described in this report. Genome analysis revealed pathways enabling oxidation of molecular hydrogen, proteinaceous substrates, fatty acids, aromatic compounds, n-alkanes, and organic acids, including acetate, through anaerobic respiration linked to Fe(III) reduction. Consistent with the inability of G. acetivorans to grow on carbohydrates, the modified Embden-Meyerhof pathway encoded by the genome is incomplete. Autotrophic CO2 fixation is enabled by the Wood-Ljungdahl pathway. Reduction of insoluble poorly crystalline Fe(III) oxide depends on the transfer of electrons from the quinone pool to multiheme c-type cytochromes exposed on the cell surface. Direct contact of the cells and Fe(III) oxide particles could be facilitated by pilus-like appendages. Genome analysis indicated the presence of metabolic pathways for anaerobic degradation of aromatic compounds and n-alkanes, although an ability of G. acetivorans to grow on these substrates was not observed in laboratory experiments. Overall, our results suggest that Geoglobus species could play an important role in microbial communities of deep-sea hydrothermal vents as lithoautotrophic producers. An additional role as decomposers would close the biogeochemical cycle of carbon through complete mineralization of various organic compounds via Fe(III) respiration. PMID:25416759

  10. PHOTOACTIVATION AND TOXICITY OF MIXTURES OF POLYCYCLIC AROMATIC HYDROCARBON COMPOUNDS IN MARINE SEDIMENT

    EPA Science Inventory

    The direct toxicity and photoinduced toxicity of sediment-associated acenaphthene, phenanthrene, fluoranthene, and pyrene were determined for the marine amphipod Rhepoxynius abronius. The four polycyclic aromatic hydrocarbons (PAHs) were spiked into sediment in a concentration se...

  11. Polycyclic aromatic compounds as anticancer agents: synthesis and biological evaluation of methoxy dibenzofluorene derivatives

    PubMed Central

    Becker, Frederick F.; Banik, Bimal K.

    2014-01-01

    Synthesis of a new methoxy dibenzofluorene through alkylation, cyclodehydration and aromatization in a one-pot operation is achieved for the first time. Using this hydrocarbon, a few derivatives are prepared through aromatic nitration, catalytic hydrogenation, coupling reaction with a side chain and reduction. The benzylic position of this hydrocarbon with the side chain is oxidized and reduced. Some of these derivatives have demonstrated excellent antitumor activities in vitro. This study confirms antitumor activity depends on the structures of the molecules. PMID:25136549

  12. Determination of the aromatic compounds in plant cuticular waxes using FT-IR spectroscopy

    NASA Astrophysics Data System (ADS)

    Dubis, Eligiusz N.; Dubis, Alina T.; Popławski, J.

    2001-09-01

    The infrared study of the aromatic components of hops ( Humulus lupulus) cuticular wax was performed. HATR FT-IR technique for fresh leaves and their extract analysis was applied. Phenylmethyl myristate, 2-phenylethyl myristate and docosyl benzoate were synthesized and used as reference standards. An absorption band in the range of 709-966 cm -1 indicates the presence of aromatic esters in plant cuticular waxes.

  13. Method and reaction pathway for selectively oxidizing organic compounds

    DOEpatents

    Camaioni, Donald M.; Lilga, Michael A.

    1998-01-01

    A method of selectively oxidizing an organic compound in a single vessel comprises: a) combining an organic compound, an acid solution in which the organic compound is soluble, a compound containing two oxygen atoms bonded to one another, and a metal ion reducing agent capable of reducing one of such oxygen atoms, and thereby forming a mixture; b) reducing the compound containing the two oxygen atoms by reducing one of such oxygen atoms with the metal ion reducing agent to, 1) oxidize the metal ion reducing agent to a higher valence state, and 2) produce an oxygen containing intermediate capable of oxidizing the organic compound; c) reacting the oxygen containing intermediate with the organic compound to oxidize the organic compound into an oxidized organic intermediate, the oxidized organic intermediate having an oxidized carbon atom; d) reacting the oxidized organic intermediate with the acid counter ion and higher valence state metal ion to bond the acid counter ion to the oxidized carbon atom and thereby produce a quantity of an ester incorporating the organic intermediate and acid counter ion; and e) reacting the oxidized organic intermediate with the higher valence state metal ion and water to produce a quantity of alcohol which is less than the quantity of ester, the acid counter ion incorporated in the ester rendering the carbon atom bonded to the counter ion less reactive with the oxygen containing intermediate in the mixture than is the alcohol with the oxygen containing intermediate.

  14. Safety in the Chemical Laboratory: Nitric Acid, Nitrates, and Nitro Compounds.

    ERIC Educational Resources Information Center

    Bretherick, Leslie

    1989-01-01

    Discussed are the potential hazards associated with nitric acid, inorganic and organic nitrate salts, alkyl nitrates, acyl nitrates, aliphatic nitro compounds, aromatic nitro compounds, and nitration reactions. (CW)

  15. How does predation affect the bioaccumulation of hydrophobic organic compounds in aquatic organisms?

    PubMed

    Xia, Xinghui; Li, Husheng; Yang, Zhifeng; Zhang, Xiaotian; Wang, Haotian

    2015-04-21

    It is well-known that the body burden of hydrophobic organic compounds (HOCs) increases with the trophic level of aquatic organisms. However, the mechanism of HOC biomagnification is not fully understood. To fill this gap, this study investigated the effect of predation on the bioaccumulation of polycyclic aromatic hydrocarbons (PAHs), one type of HOC, in low-to-high aquatic trophic levels under constant freely dissolved PAH concentrations (1, 5, or 10 μg L(-1)) maintained by passive dosing systems. The tested PAHs included phenanthrene, anthracene, fluoranthene, and pyrene. The test organisms included zebrafish, which prey on Daphnia magna, and cichlids, which prey on zebrafish. The results revealed that for both zebrafish and cichlids, predation elevated the uptake and elimination rates of PAHs. The increase of uptake rate constant ranged from 20.8% to 39.4% in zebrafish with the amount of predation of 5 daphnids per fish per day, and the PAH uptake rate constant increased with the amount of predation. However, predation did not change the final bioaccumulation equilibrium; the equilibrium concentrations of PAHs in fish only depended on the freely dissolved concentration in water. Furthermore, the lipid-normalized water-based bioaccumulation factor of each PAH was constant for fish at different trophic levels. These findings infer that the final bioaccumulation equilibrium of PAHs is related to a partition between water and lipids in aquatic organisms, and predation between trophic levels does not change bioaccumulation equilibrium but bioaccumulation kinetics at stable freely dissolved PAH concentrations. This study suggests that if HOCs have not reached bioaccumulation equilibrium, biomagnification occurs due to enhanced uptake rates caused by predation in addition to higher lipid contents in higher trophic organisms. Otherwise, it is only due to the higher lipid contents in higher trophic organisms.

  16. Singlet Fission of Non-polycyclic Aromatic Molecules in Organic Photovoltaics.

    PubMed

    Kawata, So; Pu, Yong-Jin; Saito, Ayaka; Kurashige, Yuki; Beppu, Teruo; Katagiri, Hiroshi; Hada, Masaki; Kido, Junji

    2016-02-24

    Singlet fission of thienoquinoid compounds in organic photovoltaics is demonstrated. The escalation of the thienoquinoid length of the compounds realizes a suitable packing structure and energy levels for singlet fission. The magnetic-field dependence of the photocurrent and the external quantum efficiency of the devices reveal singlet fission of the compounds and dissociation of triplet excitons into charges.

  17. Aromatic and aliphatic organic materials on Iapetus: Analysis of Cassini VIMS data

    NASA Astrophysics Data System (ADS)

    Cruikshank, Dale P.; Dalle Ore, Cristina M.; Clark, Roger N.; Pendleton, Yvonne J.

    2014-05-01

    , D.P., Clark, R.N. [2012], op. cit.) and Phoebe (Dalle Ore, C.M., Cruikshank, D.P., Clark, R.N. [2012], op. cit.). Our Gaussian decomposition of the organic band region suggests the presence of molecular bands in addition to those noted above, specifically bands attributable to cycloalkanes, olefinic compounds, CH3OH, and N-substituted PAHs, as well as possible Hn-PAHs (PAHs with excess peripheral H atoms). In a minimalist interpretation of the Gaussian band fitting, we find the ratio of aromatic CH to aliphatic CH2 + CH3 functional groups for both the leading and trailing hemispheres of Iapetus is ∼10, with no clear difference between them. In the aliphatic component of the surface material, the ratio CH2/CH3 is 4.0 on the leading hemisphere and 3.0 on the trailing; both values are higher than those found in interstellar dust and other Solar System materials and the difference between the two hemispheres may be statistically significant. The superficial layer of low-albedo material on Iapetus originated in the interior of Phoebe and is being transported to and deposited on Iapetus (and Hyperion) in the current epoch via the Phoebe dust ring (Tosi, F., Turrini, D., Coradini, A., Filacchione, G., and the VIMS Team [2010]. Mon. Not. R. Astron. Soc. 403, 1113-1130; Tamayo, D., Burns, J.A., Hamilton, D.P., Hedman, M.M. [2011]. Icarus 215, 260-278). The PAHs on Iapetus exist in a H2O-rich environment, and consequently are subject to UV destruction by hydrogenation on short time-scales. The occurrence of this material is therefore consistent with the assertion that the deposition of the PAH-bearing dust is occurring at the present time. If the organic inventory we observe represents the interior composition of Phoebe, we may be sampling the original material from a region of the solar nebula beyond Neptune where Phoebe formed prior to its capture by Saturn (Johnson, T.V., Lunine, J.I. [2005]. Nature 435, 69-71).

  18. Efficiency of conventional drinking-water-treatment processes in removal of pharmaceuticals and other organic compounds

    USGS Publications Warehouse

    Stackelberg, P.E.; Gibs, J.; Furlong, E.T.; Meyer, M.T.; Zaugg, S.D.; Lippincott, R.L.

    2007-01-01

    Samples of water and sediment from a conventional drinking-water-treatment (DWT) plant were analyzed for 113 organic compounds (OCs) that included pharmaceuticals, detergent degradates, flame retardants and plasticizers, polycyclic aromatic hydrocarbons (PAHs), fragrances and flavorants, pesticides and an insect repellent, and plant and animal steroids. 45 of these compounds were detected in samples of source water and 34 were detected in samples of settled sludge and (or) filter-backwash sediments. The average percent removal of these compounds was calculated from their average concentration in time-composited water samples collected after clarification, disinfection (chlorination), and granular-activated-carbon (GAC) filtration. In general, GAC filtration accounted for 53% of the removal of these compounds from the aqueous phase; disinfection accounted for 32%, and clarification accounted for 15%. The effectiveness of these treatments varied widely within and among classes of compounds; some hydrophobic compounds were strongly oxidized by free chlorine, and some hydrophilic compounds were partly removed through adsorption processes. The detection of 21 of the compounds in 1 or more samples of finished water, and of 3 to 13 compounds in every finished-water sample, indicates substantial but incomplete degradation or removal of OCs through the conventional DWT process used at this plant. ?? 2007 Elsevier B.V. All rights reserved.

  19. Efficiency of conventional drinking-water-treatment processes in removal of pharmaceuticals and other organic compounds.

    PubMed

    Stackelberg, Paul E; Gibs, Jacob; Furlong, Edward T; Meyer, Michael T; Zaugg, Steven D; Lippincott, R Lee

    2007-05-15

    Samples of water and sediment from a conventional drinking-water-treatment (DWT) plant were analyzed for 113 organic compounds (OCs) that included pharmaceuticals, detergent degradates, flame retardants and plasticizers, polycyclic aromatic hydrocarbons (PAHs), fragrances and flavorants, pesticides and an insect repellent, and plant and animal steroids. 45 of these compounds were detected in samples of source water and 34 were detected in samples of settled sludge and (or) filter-backwash sediments. The average percent removal of these compounds was calculated from their average concentration in time-composited water samples collected after clarification, disinfection (chlorination), and granular-activated-carbon (GAC) filtration. In general, GAC filtration accounted for 53% of the removal of these compounds from the aqueous phase; disinfection accounted for 32%, and clarification accounted for 15%. The effectiveness of these treatments varied widely within and among classes of compounds; some hydrophobic compounds were strongly oxidized by free chlorine, and some hydrophilic compounds were partly removed through adsorption processes. The detection of 21 of the compounds in 1 or more samples of finished water, and of 3 to 13 compounds in every finished-water sample, indicates substantial but incomplete degradation or removal of OCs through the conventional DWT process used at this plant.

  20. Oceanic protection of prebiotic organic compounds from UV radiation

    NASA Technical Reports Server (NTRS)

    Cleaves, H. J.; Miller, S. L.; Bada, J. L. (Principal Investigator)

    1998-01-01

    It is frequently stated that UV light would cause massive destruction of prebiotic organic compounds because of the absence of an ozone layer. The elevated UV flux of the early sun compounds this problem. This applies to organic compounds of both terrestrial and extraterrestrial origin. Attempts to deal with this problem generally involve atmospheric absorbers. We show here that prebiotic organic polymers as well as several inorganic compounds are sufficient to protect oceanic organic molecules from UV degradation. This aqueous protection is in addition to any atmospheric UV absorbers and should be a ubiquitous planetary phenomenon serving to increase the size of planetary habitable zones.

  1. Catalytic combustion of volatile organic compounds.

    PubMed

    Everaert, K; Baeyens, J

    2004-06-18

    Despite the success of adsorption and thermal incineration of (C)VOC emissions, there is still a need for research on techniques which are both economically more favorable and actually destroy the pollutants rather than merely remove them for recycling elsewhere in the biosphere. The catalytic destruction of (C)VOC to CO2, H2O and HCl/Cl2 appears very promising in this context and is the subject of the present paper. The experiments mainly investigate the catalytic combustion of eight target compounds, all of which are commonly encountered in (C)VOC emissions and/or act as precursors for the formation of PCDD/F. Available literature on the different catalysts active in the oxidation of (C)VOC is reviewed and the transition metal oxide complex V2O5-WO3/TiO2 appears most suitable for the current application. Different reactor geometries (e.g. fixed pellet beds, honeycombs, etc.) are also described. In this research a novel catalyst type is introduced, consisting of a V2O5-WO3/TiO2 coated metal fiber fleece. The conversion of (C)VOC by thermo-catalytic reactions is governed by both reaction kinetics and reaction equilibrium. Full conversion of all investigated VOC to CO2, Cl2, HCl and H2O is thermodynamically feasible within the range of experimental conditions used in this work (260-340 degrees C, feed concentrations 30-60 ppm). A first-order rate equation is proposed for the (C)VOC oxidation reactions. The apparent rate constant is a combination of reaction kinetics and mass transfer effects. The oxidation efficiencies were measured with various (C)VOC in the temperature range of 260-340 degrees C. Literature data for oxidation reactions in fixed beds and honeycomb reactors are included in the assessment. Mass transfer resistances are calculated and are generally negligible for fleece reactors and fixed pellet beds, but can be of importance for honeycomb monoliths. The experimental investigations demonstrate: (i) that the conversion of the hydrocarbons is

  2. Scavenging ratio of polycyclic aromatic compounds in rain and snow at the Athabasca oil sands region

    NASA Astrophysics Data System (ADS)

    Zhang, L.; Cheng, I.; Muir, D.; Charland, J.-P.

    2014-07-01

    Athabasca oil sands industry in northern Alberta, Canada is a possible source of polycyclic aromatic compounds (PACs). Monitored PACs, including polycyclic aromatic hydrocarbons (PAHs), alkylated PAHs, and dibenzothiophenes, in precipitation and in air at three near-source sites in the Fort MacKay and Fort McMurray area during May 2011 to August 2012 were analyzed to generate a database of scavenging (or washout) ratios (Wt) for PACs scavenged by both snow and rain. Median precipitation and air concentrations of parent PAHs over the May 2011 to August 2012 period ranged from 0.3-184.9 (chrysene) ng L-1 and 0.01-3.9 (naphthalene) ng m-3, respectively, which were comparable to literature values. Higher concentrations in precipitation and air were observed for alkylated PAHs and dibenzothiophenes. The median precipitation and air concentrations were 11.3-646.7 (C3-fluoranthene/pyrene) ng L-1 and 0.21-16.9 (C3-naphthalene) ng m-3, respectively, for alkylated PAHs, and 8.5-530.5 (C4-dibenzothiophene) ng L-1 and 0.13-6.6 (C2-dibenzothiophene) ng m-3 for dibenzothiophenes and their alkylated derivatives. Median Wt over the measurement period were 6100-1.1 × 106 from snow scavenging and 350-2.3 × 105 from rain scavenging depending on the PAC species. Median Wt for parent PAHs were within the range of those observed at other urban and suburban locations. But Wt for acenaphthylene in snow samples was 2-7 times higher. Some individual snow and rain samples exceeded literature values by a factor of 10. Wt for benzo(a)pyrene, dibenz(a,h)anthracene, and benzo(g,h,i)perylene in snow samples had reached 107, which is the maximum for PAH snow scavenging ratios reported in literature. From the analysis of data subsets, Wt for particulate-phase dominant PACs were 14-20 times greater than gas-phase dominant PACs in snow samples and 7-20 times greater than gas-phase dominant PACs in rain samples. Wt from snow scavenging was ∼9 times greater than rain scavenging for particulate

  3. Scavenging ratios of polycyclic aromatic compounds in rain and snow in the Athabasca oil sands region

    NASA Astrophysics Data System (ADS)

    Zhang, L.; Cheng, I.; Muir, D.; Charland, J.-P.

    2015-02-01

    The Athabasca oil sands industry in northern Alberta, Canada, is a possible source of polycyclic aromatic compounds (PACs). Monitored PACs, including polycyclic aromatic hydrocarbons (PAHs), alkylated PAHs, and dibenzothiophenes (DBTs), in precipitation and in air at three near-source sites in the Fort MacKay and Fort McMurray area during January 2011 to May 2012, were used to generate a database of scavenging ratios (Wt) for PACs scavenged by both snow and rain. Higher concentrations in precipitation and air were observed for alkylated PAHs and DBTs compared to the other PACs. The sums of the median precipitation concentrations over the period of data analyzed were 0.48 μ g L-1 for the 18 PAHs, 3.38 μ g L-1 for the 20 alkylated PAHs, and 0.94 μ g L-1 for the 5 DBTs. The sums of the median air concentrations for parent PAHs, alkylated PAHs, and DBTs were 8.37, 67.26, and 11.83 ng m-3, respectively. Median Wt over the measurement period were 6100 - 1.1 × 106 from snow scavenging and 350 - 2.3 × 105 from rain scavenging depending on the PAC species. Median Wt for parent PAHs were within the range of those observed at other urban and suburban locations, but Wt for acenaphthylene in snow samples were 2-7 times higher compared to other urban and suburban locations. Wt for some individual snow and rain samples exceeded literature values by a factor of 10. Wt for benzo(a)pyrene, dibenz(a,h)anthracene, and benzo(g,h,i)perylene in snow samples had reached 107, which is the maximum for PAH snow scavenging ratios reported in the literature. From the analysis of data subsets, Wt for particulate-phase dominant PACs were 14-20 times greater than gas-phase dominant PACs in snow samples and 7-20 times greater than gas-phase dominant PACs in rain samples. Wt from snow scavenging were ~ 9 times greater than from rain scavenging for particulate-phase dominant PACs and 4-9.6 times greater than from rain scavenging for gas-phase dominant PACs. Gas-particle fractions of each PAC

  4. Acid-promoted chemoselective introduction of amide functionality onto aromatic compounds mediated by an isocyanate cation generated from carbamate.

    PubMed

    Sumita, Akinari; Kurouchi, Hiroaki; Otani, Yuko; Ohwada, Tomohiko

    2014-10-01

    Carbamates have been used as precursors of isocyanates, but heating in the presence of strong acids is required because cleavage of the C-O bond in carbamates is energy-demanding even in acid media. Direct amidation of aromatic compounds by isocyanate cations generated at room temperature from carbamoyl salicylates in trifluoromethanesulfonic acid (TfOH) was examined. Carbamates with ortho-salicylate as an ether group (carbamoyl salicylates) showed dramatically accelerated O-C bond dissociation in TfOH, which resulted in facile generation of the isocyanate cation. These chemoselective intermolecular aromatic amidation reactions proceeded even at room temperature and showed good compatibility with other electrophilic functionalities and high discrimination between N-monosubstituted carbamate and N,N-disubstituted carbamate. The reaction rates of secondary and tertiary amide formation were markedly different, and this difference was utilized to achieve successive (tandem) amidation reactions of molecules with an N-monosubstituted carbamate and an N,N-disubstituted carbamate with two kinds of aromatic compounds.

  5. Activation of Ca sup 2+ uptake and inhibition of reversal of the sarcoplasmic reticulum Ca sup 2+ pump by aromatic compounds

    SciTech Connect

    Petretski, J.H.; Wolosker, H.; de Meis, L. )

    1989-12-05

    The effects of aromatic compounds in sarcoplasmic reticulum Ca2+-ATPase were investigated. The solubility of the drugs in various organic solvents and water was measured. The ratio between the solubility in organic solvents and that in water (distribution coefficient) was used as an index of their hydrophobicity. The order found was triphenylphosphine greater than diphenylamine greater than 3-nitrophenol greater than 4-nitrophenol greater than 1,3-dihydroxybenzene. The effects observed on the Ca2+-ATPase were correlated with hydrophobicity of the drugs, activation and inhibition being obtained at a lower concentration the greater the distribution coefficient of the drug into organic solvent. In leaky vesicles, the effects of each compound on the ATPase activity varied depending on the Ca2+ concentration in the medium: it inhibited in the presence of 5 microM Ca2+ and activated when the Ca2+ concentration was raised to 2 mM. In intact vesicles, 3- and 4-nitrophenol, diphenylamine, and triphenylphosphine enhanced both the rate of ATP hydrolysis and the amount of Ca2+ accumulated by the vesicles. These four drugs inhibited Ca2+ uptake when ITP was used as substrate. 1,3-Dihydroxybenzene enhanced the amount of Ca2+ accumulated by the vesicles regardless of whether ATP or ITP was the substrate. All five compounds inhibited the phosphorylation of the enzyme by Pi, the efflux of Ca2+, and the synthesis of ATP measured during the reversal of the Ca2+ pump. The results indicate that the hydrophobic character of various organic compounds determines their access to sensitive domains of the membrane-bound calcium pump. Additional specific effects are then produced, depending on the structure of each compound.

  6. Lone pair ... pi interactions between water oxygens and aromatic residues: quantum chemical studies based on high-resolution protein structures and model compounds.

    PubMed

    Jain, Alok; Ramanathan, Venkatnarayan; Sankararamakrishnan, Ramasubbu

    2009-03-01

    The pi electron cloud of aromatic centers is known to be involved in several noncovalent interactions such as C--H...pi, O--H...pi, and pi...pi interactions in biomolecules. Lone-pair (lp) ... pi interactions have gained attention recently and their role in biomolecular structures is being recognized. In this article, we have carried out systematic analysis of high-resolution protein structures and identified more than 400 examples in which water oxygen atoms are in close contact (distance < 3.5 A) with the aromatic centers of aromatic residues. Three different methods were used to build hydrogen atoms and we used a consensus approach to find out potential candidates for lp...pi interactions between water oxygen and aromatic residues. Quantum mechanical calculations at MP2/6-311++G(d,p) level on model systems based on protein structures indicate that majority of the identified examples have energetically favorable interactions. The influence of water hydrogen atoms was investigated by sampling water orientations as a function of two parameters: distance from the aromatic center and the angle between the aromatic plane and the plane formed by the three water atoms. Intermolecular potential surfaces were constructed using six model compounds representing the four aromatic amino acids and 510 different water orientations for each model compound. Ab initio molecular orbital calculations at MP2/6-311++G(d,p) level show that the interaction energy is favorable even when hydrogen atoms are farthest from the aromatic plane while water oxygen is pointing toward the aromatic center. The strength of such interaction depends upon the distance of water hydrogen atoms from the aromatic substituents. Our calculations clearly show that the lp...pi interactions due to the close approach of water oxygen and aromatic center are influenced by the positions of water hydrogen atoms and the aromatic substituents.

  7. [Organisms producing hypolipidemic compounds with antioxidant activity].

    PubMed

    Puzhevskaia, T O; Grammatikova, N E; Bibikova, M V; Katlinskiĭ, A V

    2009-01-01

    Complex compounds produced by fungal cultures of Lecanicilium and Beauveria with both high hypolipidemic and antioxydant activities were screened. Two fractions of the hypolipipidemic compounds with antioxidant activity of 95 and 75% in a dose of 25 mcg/ml were isolated.

  8. Organic compounds in hot-water-soluble fractions from water repellent soils

    NASA Astrophysics Data System (ADS)

    Atanassova, Irena; Doerr, Stefan

    2014-05-01

    Water repellency (WR) is a soil property providing hydrophobic protection and preventing rapid microbial decomposition of organic matter entering the soil with litter or plant residues. Global warming can cause changes in WR, thus influencing water storage and plant productivity. Here we assess two different approaches for analysis of organic compounds composition in hot water extracts from accelerated solvent extraction (ASE) of water repellent soils. Extracts were lyophilized, fractionated on SiO2 (sand) and SPE cartridge, and measured by GC/MS. Dominant compounds were aromatic acids, short chain dicarboxylic acids (C4-C9), sugars, short chain fatty acids (C8-C18), and esters of stearic and palmitic acids. Polar compounds (mainly sugars) were adsorbed on applying SPE clean-up procedure, while esters were highly abundant. In addition to the removal of polar compounds, hydrophobic esters and hydrocarbons (alkanes and alkenes < C20) were extracted through desorption of complex colloids stabilized as micelles in dissolved organic carbon (DOC). Water repellency was completely eliminated by hot water under high pressure. The molecular composition of HWSC can play a critical role in stabilization and destabilization of soil organic matter (SOM), particle wettability and C dynamics in soils. Key words: soil water repellency, hot water soluble carbon (HWSC), GC/MS, hydrophobic compounds

  9. Relative Stabilities of Organic Compounds Using Benson's Additivity Rules.

    ERIC Educational Resources Information Center

    Vitale, Dale E.

    1986-01-01

    Shows how the structure-energy principle can be presented in organic chemistry (without having to resort to quantum mechanics) by use of Benson's Additive Rules. Examples of the application to several major classes of organic compounds are given.

  10. Sorption interactions of organic compounds with soils affected by agricultural olive mill wastewater.

    PubMed

    Keren, Yonatan; Borisover, Mikhail; Bukhanovsky, Nadezhda

    2015-11-01

    The organic compound-soil interactions may be strongly influenced by changes in soil organic matter (OM) which affects the environmental fate of multiple organic pollutants. The soil OM changes may be caused by land disposal of various OM-containing wastes. One unique type of OM-rich waste is olive mill-related wastewater (OMW) characterized by high levels of OM, the presence of fatty aliphatics and polyphenolic aromatics. The systematic data on effects of the land-applied OMW on organic compound-soil interactions is lacking. Therefore, aqueous sorption of simazine and diuron, two herbicides, was examined in batch experiments onto three soils, including untreated and OMW-affected samples. Typically, the organic compound-soil interactions increased following the prior land application of OMW. This increase is associated with the changes in sorption mechanisms and cannot be attributed solely to the increase in soil organic carbon content. A novel observation is that the OMW application changes the soil-sorbent matrix in such a way that the solute uptake may become cooperative or the existing ability of a soil sorbent to cooperatively sorb organic molecules from water may become characterized by a larger affinity. The remarkable finding of this study was that in some cases a cooperative uptake of organic molecules by soils makes itself evident in distinct sigmoidal sorption isotherms rarely observed in soil sorption of non-ionized organic compounds; the cooperative herbicide-soil interactions may be characterized by the Hill model coefficients. However, no single trend was found for the effect of applied OMW on the mechanisms of organic compound-soil interactions.

  11. Production of Monomeric Aromatic Compounds from Oil Palm Empty Fruit Bunch Fiber Lignin by Chemical and Enzymatic Methods.

    PubMed

    Tang, Pei-Ling; Hassan, Osman; Maskat, Mohamad Yusof; Badri, Khairiah

    2015-01-01

    In this study, oil palm empty fruit bunch (OPEFBF) was pretreated with alkali, and lignin was extracted for further degradation into lower molecular weight phenolic compounds using enzymes and chemical means. Efficiency of monomeric aromatic compounds production from OPEFBF lignin via chemical (nitrobenzene versus oxygen) and enzymatic [cutinase versus manganese peroxidase (MnP)] approaches was investigated. The effects of sodium hydroxide concentration (2, 5, and 10% wt.) and reaction time (30, 90, and 180 minutes) on the yield of aromatic compounds were studied. The results obtained indicated that nitrobenzene oxidation produced the highest yield (333.17 ± 49.44 ppm hydroxybenzoic acid, 5.67 ± 0.25 ppm p-hydroxybenzaldehyde, 25.57 ± 1.64 ppm vanillic acid, 168.68 ± 23.23 ppm vanillin, 75.44 ± 6.71 ppm syringic acid, 815.26 ± 41.77 ppm syringaldehyde, 15.21 ± 2.19 ppm p-coumaric acid, and 44.75 ± 3.40 ppm ferulic acid), among the tested methods. High sodium hydroxide concentration (10% wt.) was needed to promote efficient nitrobenzene oxidation. However, less severe oxidation condition was preferred to preserve the hydroxycinnamic acids (p-coumaric acid and ferulic acid). Cutinase-catalyzed hydrolysis was found to be more efficient than MnP-catalyzed oxidation in the production of aromatic compounds. By hydrolyzed 8% wt. of lignin with 0.625 mL cutinase g(-1) lignin at pH 8 and 55°C for 24 hours, about 642.83 ± 14.45 ppm hydroxybenzoic acid, 70.19 ± 3.31 ppm syringaldehyde, 22.80 ± 1.04 ppm vanillin, 27.06 ± 1.20 ppm p-coumaric acid, and 50.19 ± 2.23 ppm ferulic acid were produced.

  12. Influence of Magnesium Perchlorate on the Pyrolysis of Organic Compounds in Martian Soil Analogs

    NASA Astrophysics Data System (ADS)

    Steininger, Harald; Goesmann, Fred

    2010-05-01

    Detection and identification of organic molecules derived from present or past life is the goal of the Martian Organic Molecule Analyser of the 2018 ExoMars mission of ESA. One part of the instrument is a pyrolysis gas chromatograph mass spectrometer pyr-GC-MS while the other is a laser desorption mass spectrometer. In the pyr-GC-MS a soil sample of app. 200 mg and then heated to a temperature of 900°C. [1] During this process the organic molecules desorb from the surface and are separated on the column of the GC and identified in the MS. The direct pyrolysis of soil samples without previous extraction is an uncommon way of sample preparation. In addition to the parameters of the pyrolysis of pure samples, for example temperatures and the soil composition influences the measurements in several ways. To evaluate the influence of the relative large surface of the soil on the pyrolysis and derivatization several tests have been conducted with simple organic molecules. The Phoenix mission discovered considerable amounts of magnesium perchlorate in the soil at the landing site. Perchlorates are oxidizing components and therefore might interact with the expected organics within the soil, especially if the soil is heated within the pyrolysis ovens. The end-product of this oxidation would be carbon dioxide which is indistinguishable from the atmospheric carbon dioxide. For the test several organic compounds have been used, for example phenylalanine and benzoic acid. Carboxylic acids are stable intermediates in the oxidation of aromatic compounds and therefore the simplest aromatic carboxylic acid, benzoic acid has been considered to be present on Mars. [2] Along with oxidation of the used compounds also chlorination of the aromatic rings was observed. This reaction leads to a large variety of chlorinated aromatics which would be easy to detect in the GC-MS. A further investigation on the concentration dependency of this reaction is planned. References [1] Geffroy

  13. Investigation of the distribution of organochlorine and polycyclic aromatic hydrocarbon compounds in the Lower Columbia River using semipermeable-membrane devices

    USGS Publications Warehouse

    McCarthy, Kathleen A.; Gale, Robert W.

    1999-01-01

    Organochlorine and polycyclic aromatic hydrocarbon compounds are of concern in the Columbia River Basin because of their adverse effects on fish and wildlife. Because these compounds can have important biological consequences at concentrations well below the detection limits associated with conventional water-sampling techniques, we used semipermeable membrane devices (SPMDs) to sample water, and achieved sub-parts-per-quintillion detection limits. We deployed SPMDs during 1997 low-flow conditions and 1998 high-flow conditions at nine main-stem sites and seven tributary sites, spanning approximately 700 miles of the Columbia River. We also collected streambed sediment from three sites. SPMD extracts and sediments were analyzed for polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans, polychlorinated biphenyls, organochlorine pesticides and related transformation products, and polycyclic aromatic hydrocarbons. Our data indicate that (1) in the absence of additional sources, mechanisms such as volatilization, dilution, and settling of suspended particles can act to significantly reduce concentrations of contaminants along the river's flow path, (2) elevated concentrations of contaminants in the Portland-Vancouver area are primarily from local rather than upstream sources, (3) elevated concentrations of many compounds tend to be diluted during periods of high discharge, (4) much higher discharge in the main stem considerably dilutes elevated concentrations entering from tributaries, (5) the distribution of hydrophobic organic compounds in streambed sediment is not necessarily indicative of their distribution in the dissolved-phase, and (6) SPMDs can reveal patterns of contaminant occurrence at environmentally relevant concentrations that are undetectable by conventional water-sampling techniques.

  14. Search for organic compounds in the lunar dust from the sea of tranquillity

    USGS Publications Warehouse

    Ponnamperuma, C.; Kvenvolden, K.; Chang, S.; Johnson, R.; Pollock, G.; Philpott, D.; Kaplan, I.; Smith, J.; Schopf, J.W.; Gehrke, C.; Hodgson, G.; Breger, I.A.; Halpern, B.; Duffield, A.; Krauskopf, K.; Barghoorn, E.; Holland, H.; Keil, Klaus

    1970-01-01

    A sample of lunar dust was examined for organic compounds. Carbon detected in concentrations of 157 micrograms per gram had a ??13C per mil (PDB) value of +20. Treatment with hydrochloric acid yielded hydrocarbons of low molecular weight, suggesting the presence of carbides. The gas chromatogram of the acylated and esterified derivatives of the hydrolyzate was similar to that obtained for the Pueblito de Allende meteorite. There were no detectable amounts of extractable high-molecular-weight alkanes, aromatic hydrocarbons, isoprenoid hydrocarbons, normal alkanes, fatty acids, amino acids, sugars, or nucleic acid bases. Traces of porphyrins were found, perhaps arising from rocket exhaust materials.

  15. Search for organic compounds in the lunar dust from the sea of tranquiblity.

    PubMed

    Ponnamperuma, C; Kvenvolden, K; Chang, S; Johnson, R; Pollock, G; Philpott, D; Kaplan, I; Smith, J; Schopf, J W; Gehrke, C; Hodgson, G; Breger, I A; Halpern, B; Duffield, A; Krauskopf, K; Barghoorn, E; Holland, H; Keil, K

    1970-01-30

    A sample of lunar dust was examined for organic compounds. Carbon detected in concentrations of 157 micrograms per gram had a delta(13)C per mil (PDB) value of + 20. Treatment with hydrochloric acid yielded hydrocarbons of low molecular weight, suggesting the presence of carbides. The gas chromatogram of the acylated and esterified derivatives of the hydrolyzate was similar to that obtained for the Pueblito de Allende meteorite. There were no detectable amounts of extractable high-molecular-weight alkanes, aromatic hydrocarbons, isoprenoid hydrocarbons, normal alkanes, fatty acids, amino acids, sugars, or nucleic acid bases. Traces of porphyrins were found, perhaps arising from rocket exhaust materials.

  16. Headspace in-tube microextraction coupled with micellar electrokinetic chromatography of neutral aromatic compounds.

    PubMed

    Cho, Sung Min; Park, Bum Su; Jung, Woo Sung; Lee, Sang Won; Jung, Yunhwan; Chung, Doo Soo

    2016-02-01

    Headspace (HS) extraction can be carried out easily and aptly via single drop microextraction coupled with capillary electrophoresis (CE). However, one drawback is the difficulty of keeping the single drop stably at the capillary tip. To solve this problem, we have recently demonstrated HS in-tube microextraction (ITME) of acidic compounds such as chlrophenols in an acidic sample using a basic run buffer plug in the separation capillary for CE as an acceptor phase. In this report, an organic acceptor plug in a capillary was used to extract neutral organic volatile pollutants such as BTEX (benzene, toluene, ethylbenzene, and m-xylene). After extraction, the analytes enriched in the organic acceptor plug were analyzed with micellar electrokinetic chromatography (MEKC). The enrichment factors for BTEX in a standard solution were up to 350 under an optimal condition of 25°C for 20 min. As an application, BTEX spiked into bottled water were analyzed with HS-ITME-MEKC, and the enrichment factors for BTEX were up to 320. The limits of detections were 1-4 ppb, which are at least 200 times lower than the US Environmental Protection Agency guidelines for drinking water, except benzene. The entire procedure of HS-ITME-MEKC was carried out automatically using a commercial CE instrument.

  17. FIELD SCREENING FOR HALOGENATED VOLATILE ORGANIC COMPOUNDS

    SciTech Connect

    John F. Schabron; Joseph F. Rovani, Jr.; Theresa M. Bomstad

    2003-07-01

    Western Research Institute (WRI) is continuing work toward the development of new screening methodology and a test kit to measure halogenated volatile organic compounds (VOCs) in the field. Heated diode and corona discharge sensors are commonly used to detect leaks of refrigerants from air conditioners, freezers, and refrigerators. They are both selective to the presence of halogens. In prior work, the devices were tested for response to carbon tetrachloride, heptane, toluene, and water vapors. In the current work, sensor response was evaluated with sixteen halogenated VOCs relative to carbon tetrachloride. The results show that the response of the various chlorinated VOCs is within an order of magnitude of the response to carbon tetrachloride for each of the sensors. Thus, for field screening a single response factor can be used. Both types of leak detectors are being further modified to provide an on-board LCD signal readout, which is related to VOC concentration. The units will be fully portable and will operate with 115-V line or battery power. Signal background, noise level, and response data on the Bacharach heated diode detector and the TIF corona discharge detector show that when the response curves are plotted against the log of concentration, the plot is linear to the upper limit for the particular unit, with some curvature at lower levels. When response is plotted directly against concentration, the response is linear at the low end and is curved at the high end. The dynamic ranges for carbon tetrachloride of the two devices from the lower detection limit (S/N=2) to signal saturation are 4-850 vapor parts per million (vppm) for the corona discharge unit and 0.01-70 vppm for the heated diode unit. Additional circuit modifications are being made to lower the detection limit and increase the dynamic response range of the corona discharge unit. The results indicate that both devices show potential utility for future analytical method development work toward

  18. 40 CFR 60.462 - Standards for volatile organic compounds.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

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  19. 40 CFR 60.492 - Standards for volatile organic compounds.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

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  20. 40 CFR 60.582 - Standard for volatile organic compounds.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 7 2014-07-01 2014-07-01 false Standard for volatile organic compounds. 60.582 Section 60.582 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... Flexible Vinyl and Urethane Coating and Printing § 60.582 Standard for volatile organic compounds. (a)...

  1. 40 CFR 60.462 - Standards for volatile organic compounds.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 7 2014-07-01 2014-07-01 false Standards for volatile organic compounds. 60.462 Section 60.462 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... Coil Surface Coating § 60.462 Standards for volatile organic compounds. (a) On and after the date...

  2. 40 CFR 60.462 - Standards for volatile organic compounds.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 6 2011-07-01 2011-07-01 false Standards for volatile organic compounds. 60.462 Section 60.462 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... Coil Surface Coating § 60.462 Standards for volatile organic compounds. (a) On and after the date...

  3. 40 CFR 60.602 - Standard for volatile organic compounds.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Standard for volatile organic compounds. 60.602 Section 60.602 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... Synthetic Fiber Production Facilities § 60.602 Standard for volatile organic compounds. On and after...

  4. 40 CFR 60.462 - Standards for volatile organic compounds.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 7 2013-07-01 2013-07-01 false Standards for volatile organic compounds. 60.462 Section 60.462 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... Coil Surface Coating § 60.462 Standards for volatile organic compounds. (a) On and after the date...

  5. 40 CFR 60.712 - Standards for volatile organic compounds.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 6 2011-07-01 2011-07-01 false Standards for volatile organic compounds. 60.712 Section 60.712 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... Magnetic Tape Coating Facilities § 60.712 Standards for volatile organic compounds. Each owner or...

  6. 40 CFR 60.622 - Standards for volatile organic compounds.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

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  7. 40 CFR 60.452 - Standard for volatile organic compounds.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

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  8. 40 CFR 60.582 - Standard for volatile organic compounds.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Standard for volatile organic compounds. 60.582 Section 60.582 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... Flexible Vinyl and Urethane Coating and Printing § 60.582 Standard for volatile organic compounds. (a)...

  9. 40 CFR 60.492 - Standards for volatile organic compounds.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 6 2011-07-01 2011-07-01 false Standards for volatile organic compounds. 60.492 Section 60.492 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... Beverage Can Surface Coating Industry § 60.492 Standards for volatile organic compounds. On or after...

  10. 40 CFR 60.602 - Standard for volatile organic compounds.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 7 2013-07-01 2013-07-01 false Standard for volatile organic compounds. 60.602 Section 60.602 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... Synthetic Fiber Production Facilities § 60.602 Standard for volatile organic compounds. On and after...

  11. 40 CFR 60.742 - Standards for volatile organic compounds.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 6 2011-07-01 2011-07-01 false Standards for volatile organic compounds. 60.742 Section 60.742 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... Polymeric Coating of Supporting Substrates Facilities § 60.742 Standards for volatile organic compounds....

  12. 40 CFR 60.452 - Standard for volatile organic compounds.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 7 2014-07-01 2014-07-01 false Standard for volatile organic compounds. 60.452 Section 60.452 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... Industrial Surface Coating: Large Appliances § 60.452 Standard for volatile organic compounds. On or...

  13. 40 CFR 60.622 - Standards for volatile organic compounds.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Standards for volatile organic compounds. 60.622 Section 60.622 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... Petroleum Dry Cleaners § 60.622 Standards for volatile organic compounds. (a) Each affected...

  14. 40 CFR 60.622 - Standards for volatile organic compounds.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 6 2011-07-01 2011-07-01 false Standards for volatile organic compounds. 60.622 Section 60.622 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... Petroleum Dry Cleaners § 60.622 Standards for volatile organic compounds. (a) Each affected...

  15. 40 CFR 60.452 - Standard for volatile organic compounds.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 7 2012-07-01 2012-07-01 false Standard for volatile organic compounds. 60.452 Section 60.452 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... Industrial Surface Coating: Large Appliances § 60.452 Standard for volatile organic compounds. On or...

  16. 40 CFR 60.452 - Standard for volatile organic compounds.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Standard for volatile organic compounds. 60.452 Section 60.452 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... Industrial Surface Coating: Large Appliances § 60.452 Standard for volatile organic compounds. On or...

  17. 40 CFR 60.582 - Standard for volatile organic compounds.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 7 2013-07-01 2013-07-01 false Standard for volatile organic compounds. 60.582 Section 60.582 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... Flexible Vinyl and Urethane Coating and Printing § 60.582 Standard for volatile organic compounds. (a)...

  18. 40 CFR 60.582 - Standard for volatile organic compounds.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 6 2011-07-01 2011-07-01 false Standard for volatile organic compounds. 60.582 Section 60.582 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... Flexible Vinyl and Urethane Coating and Printing § 60.582 Standard for volatile organic compounds. (a)...

  19. 40 CFR 60.462 - Standards for volatile organic compounds.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 7 2012-07-01 2012-07-01 false Standards for volatile organic compounds. 60.462 Section 60.462 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... Coil Surface Coating § 60.462 Standards for volatile organic compounds. (a) On and after the date...

  20. 40 CFR 60.492 - Standards for volatile organic compounds.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 7 2012-07-01 2012-07-01 false Standards for volatile organic compounds. 60.492 Section 60.492 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... Beverage Can Surface Coating Industry § 60.492 Standards for volatile organic compounds. On or after...

  1. 40 CFR 60.622 - Standards for volatile organic compounds.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 7 2013-07-01 2013-07-01 false Standards for volatile organic compounds. 60.622 Section 60.622 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... Petroleum Dry Cleaners § 60.622 Standards for volatile organic compounds. (a) Each affected...

  2. 40 CFR 60.712 - Standards for volatile organic compounds.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 7 2014-07-01 2014-07-01 false Standards for volatile organic compounds. 60.712 Section 60.712 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... Magnetic Tape Coating Facilities § 60.712 Standards for volatile organic compounds. Each owner or...

  3. 40 CFR 60.622 - Standards for volatile organic compounds.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 7 2012-07-01 2012-07-01 false Standards for volatile organic compounds. 60.622 Section 60.622 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... Petroleum Dry Cleaners § 60.622 Standards for volatile organic compounds. (a) Each affected...

  4. 40 CFR 60.722 - Standards for volatile organic compounds.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 7 2013-07-01 2013-07-01 false Standards for volatile organic compounds. 60.722 Section 60.722 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... volatile organic compounds. (a) Each owner or operator of any affected facility which is subject to...

  5. 40 CFR 60.602 - Standard for volatile organic compounds.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 7 2014-07-01 2014-07-01 false Standard for volatile organic compounds. 60.602 Section 60.602 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... Synthetic Fiber Production Facilities § 60.602 Standard for volatile organic compounds. On and after...

  6. 40 CFR 60.742 - Standards for volatile organic compounds.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 7 2014-07-01 2014-07-01 false Standards for volatile organic compounds. 60.742 Section 60.742 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... Polymeric Coating of Supporting Substrates Facilities § 60.742 Standards for volatile organic compounds....

  7. 40 CFR 60.602 - Standard for volatile organic compounds.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 6 2011-07-01 2011-07-01 false Standard for volatile organic compounds. 60.602 Section 60.602 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... Synthetic Fiber Production Facilities § 60.602 Standard for volatile organic compounds. On and after...

  8. 40 CFR 60.712 - Standards for volatile organic compounds.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 7 2013-07-01 2013-07-01 false Standards for volatile organic compounds. 60.712 Section 60.712 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... Magnetic Tape Coating Facilities § 60.712 Standards for volatile organic compounds. Each owner or...

  9. 40 CFR 60.602 - Standard for volatile organic compounds.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 7 2012-07-01 2012-07-01 false Standard for volatile organic compounds. 60.602 Section 60.602 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... Synthetic Fiber Production Facilities § 60.602 Standard for volatile organic compounds. On and after...

  10. 40 CFR 60.582 - Standard for volatile organic compounds.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 7 2012-07-01 2012-07-01 false Standard for volatile organic compounds. 60.582 Section 60.582 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... Flexible Vinyl and Urethane Coating and Printing § 60.582 Standard for volatile organic compounds. (a)...

  11. 40 CFR 60.742 - Standards for volatile organic compounds.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 7 2012-07-01 2012-07-01 false Standards for volatile organic compounds. 60.742 Section 60.742 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... Polymeric Coating of Supporting Substrates Facilities § 60.742 Standards for volatile organic compounds....

  12. 40 CFR 60.712 - Standards for volatile organic compounds.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 7 2012-07-01 2012-07-01 false Standards for volatile organic compounds. 60.712 Section 60.712 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... Magnetic Tape Coating Facilities § 60.712 Standards for volatile organic compounds. Each owner or...

  13. 40 CFR 60.492 - Standards for volatile organic compounds.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 7 2014-07-01 2014-07-01 false Standards for volatile organic compounds. 60.492 Section 60.492 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... Beverage Can Surface Coating Industry § 60.492 Standards for volatile organic compounds. On or after...

  14. 40 CFR 60.742 - Standards for volatile organic compounds.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 7 2013-07-01 2013-07-01 false Standards for volatile organic compounds. 60.742 Section 60.742 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... Polymeric Coating of Supporting Substrates Facilities § 60.742 Standards for volatile organic compounds....

  15. 40 CFR 60.492 - Standards for volatile organic compounds.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Standards for volatile organic compounds. 60.492 Section 60.492 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... Beverage Can Surface Coating Industry § 60.492 Standards for volatile organic compounds. On or after...

  16. 40 CFR 60.722 - Standards for volatile organic compounds.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 7 2014-07-01 2014-07-01 false Standards for volatile organic compounds. 60.722 Section 60.722 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... volatile organic compounds. (a) Each owner or operator of any affected facility which is subject to...

  17. 40 CFR 60.722 - Standards for volatile organic compounds.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 6 2011-07-01 2011-07-01 false Standards for volatile organic compounds. 60.722 Section 60.722 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... volatile organic compounds. (a) Each owner or operator of any affected facility which is subject to...

  18. 40 CFR 60.722 - Standards for volatile organic compounds.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Standards for volatile organic compounds. 60.722 Section 60.722 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... volatile organic compounds. (a) Each owner or operator of any affected facility which is subject to...

  19. 40 CFR 60.722 - Standards for volatile organic compounds.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 7 2012-07-01 2012-07-01 false Standards for volatile organic compounds. 60.722 Section 60.722 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... volatile organic compounds. (a) Each owner or operator of any affected facility which is subject to...

  20. 40 CFR 60.452 - Standard for volatile organic compounds.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 7 2013-07-01 2013-07-01 false Standard for volatile organic compounds. 60.452 Section 60.452 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... Industrial Surface Coating: Large Appliances § 60.452 Standard for volatile organic compounds. On or...

  1. 40 CFR 60.712 - Standards for volatile organic compounds.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Standards for volatile organic compounds. 60.712 Section 60.712 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... Magnetic Tape Coating Facilities § 60.712 Standards for volatile organic compounds. Each owner or...

  2. 40 CFR 60.742 - Standards for volatile organic compounds.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Standards for volatile organic compounds. 60.742 Section 60.742 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... Polymeric Coating of Supporting Substrates Facilities § 60.742 Standards for volatile organic compounds....

  3. A Systematic Presentation of Organic Phosphorus and Sulfur Compounds.

    ERIC Educational Resources Information Center

    Hendrickson, James B.

    1985-01-01

    Because the names, interrelations, and oxidation levels of the organic compounds of phosphorus and sulfur tend to confuse students, a simple way to organize these compounds has been developed. The system consists of grouping them by oxidation state and extent of carbon substitution. (JN)

  4. Environmentally friendly organic synthesis using bismuth(III) compounds.

    PubMed

    Krabbe, Scott W; Mohan, Ram S

    2012-01-01

    With increasing environmental concerns, the need for environmentally friendly organic synthesis has gained increased importance. In this regard, bismuth(III) compounds are especially attractive as "green" reagents and catalysts for organic synthesis. Bismuth(III) compounds are remarkably nontoxic, relatively air and moisture stable, and easy to handle. The contributions from our laboratory in the last 5 years in the field of applications of bismuth(III) compounds as catalysts are presented.

  5. Incremental Reactivity Effects of Anthropogenic and Biogenic Volatile Organic Compounds on Secondary Organic Aerosol Formation

    NASA Astrophysics Data System (ADS)

    Kacarab, M.; Li, L.; Carter, W. P. L.; Cocker, D. R., III

    2015-12-01

    Two surrogate reactive organic gas (ROG) mixtures were developed to create a controlled reactivity environment simulating different urban atmospheres with varying levels of anthropogenic (e.g. Los Angeles reactivity) and biogenic (e.g. Atlanta reactivity) influences. Traditional chamber experiments focus on the oxidation of one or two volatile organic compound (VOC) precursors, allowing the reactivity of the system to be dictated by those compounds. Surrogate ROG mixtures control the overall reactivity of the system, allowing for the incremental aerosol formation from an added VOC to be observed. The surrogate ROG mixtures were developed based on that used to determine maximum incremental reactivity (MIR) scales for O3 formation from VOC precursors in a Los Angeles smog environment. Environmental chamber experiments were designed to highlight the incremental aerosol formation in the simulated environment due to the addition of an added anthropogenic (aromatic) or biogenic (terpene) VOC. All experiments were conducted in the UC Riverside/CE-CERT dual 90m3 environmental chambers. It was found that the aerosol precursors behaved differently under the two altered reactivity conditions, with more incremental aerosol being formed in the anthropogenic ROG system than in the biogenic ROG system. Further, the biogenic reactivity condition inhibited the oxidation of added anthropogenic aerosol precursors, such as m-xylene. Data will be presented on aerosol properties (density, volatility, hygroscopicity) and bulk chemical composition in the gas and particle phases (from a SYFT Technologies selected ion flow tube mass spectrometer, SIFT-MS, and Aerodyne high resolution time of flight aerosol mass spectrometer, HR-ToF-AMS, respectively) comparing the two controlled reactivity systems and single precursor VOC/NOx studies. Incremental aerosol yield data at different controlled reactivities provide a novel and valuable insight in the attempt to extrapolate environmental chamber

  6. [Source profile and chemical reactivity of volatile organic compounds from vehicle exhaust].

    PubMed

    Qiao, Yue-Zhen; Wang, Hong-Li; Huang, Cheng; Chen, Chang-Hong; Su, Lei-Yan; Zhou, Min; Xu, Hua; Zhang, Gang-Feng; Chen, Yi-Ran; Li, Li; Chen, Ming-Hua; Huang, Hai-Ying

    2012-04-01

    Light-duty gasoline taxis (LDGT) and passenger cars (LDGV), heavy-duty diesel buses (HDDB) and trucks (HDDT), gasoline motorcycles (MC) and LPG scooters (LPGS), were selected for tailpipe volatile organic compounds (VOCs) samplings by using transient dynamometer and on road test combined with SUMMA canisters technology. The samples were tested by GC-MS to analyze the concentration and species composition of VOCs. The results indicate that light-duty gasoline automobiles have higher fractions of aromatic hydrocarbons, which account for 43.38%-44.45% of the total VOCs, the main aromatic hydrocarbons are toluene and xylenes. Heavy-duty diesel vehicles have higher fractions of alkanes, which constitute 46.86%-48.57% of the total VOCs, the main alkanes are propane, n-dodecane and n-undecane. In addition, oxy-organics account for 13.28%-15.01% of the VOCs, the main oxy-organics is acetone. The major compound from MC and LPGS exhaust is acetylene, it accounts for 39.75% and 76.67% of the total VOCs, respectively. VOCs exhaust from gasoline motorcycles and light-duty gasoline automobiles has a significantly higher chemical reactivity than those from heavy-duty diesel vehicles, which contribute 55% and 44% to the atmospheric chemical reactivity in Shanghai. The gasoline motorcycles and light-duty gasoline automobiles are the key pollution sources affecting city and region ambient oxidation, and the key active species of toluene, xylenes, propylene, and styrene make the greatest contribution.

  7. Application of FT-IR spectroscopy for control of the medium composition during the biodegradation of nitro aromatic compounds.

    PubMed

    Grube, Mara; Muter, Olga; Strikauska, Silvija; Gavare, Marita; Limane, Baiba

    2008-11-01

    Previous studies showed that cabbage leaf extract (CLE) added to the growth medium can noticeably promote the degradation of nitro aromatic compounds by specific consortium of bacteria upon their growth. For further development of the approach for contaminated soil remediation it was necessary to evaluate the qualitative and/or quantitative composition of different origin CLE and their relevance on the growth of explosives-degrading bacteria. Six CLE (different by species, cultivars and harvesting time) were tested and used as additives to the growth medium. It was shown that nitro aromatic compounds can be identified in the FT-IR absorption spectra by the characteristic band at 1,527 cm(-1), and in CLE by the characteristic band at 1,602 cm(-1). The intensity of the CLE band at 1,602 cm(-1) correlated with the concentration of total nitrogen (R2=0.87) and decreased upon the growth of bacteria. The content of nitrogen in CLE differed (0.22-1.00 vol.%) and significantly influenced the content of total carbohydrates (9.50-16.00% DW) and lipids [3.90-9.90% dry weight (DW)] accumulated in bacterial cells while the content of proteins was similar in all samples. Though this study showed quantitative differences in the composition of the studied CLE and the response of bacterial cells to the composition of the growth media, and proved the potential of this additive for remediation of contaminated soil. It was shown that analysis of CLE and monitoring of the conversion of nitro aromatic compounds can be investigated by FT-IR spectroscopy as well as by conventional chemical methods.

  8. SiRNAs conjugated with aromatic compounds induce RISC-mediated antisense strand selection and strong gene-silencing activity

    SciTech Connect

    Kubo, Takanori; Yanagihara, Kazuyoshi; Takei, Yoshifumi; Mihara, Keichiro; Sato, Yuichiro; Seyama, Toshio

    2012-10-05

    Highlights: Black-Right-Pointing-Pointer SiRNAs conjugated with aromatic compounds (Ar-siRNAs) at 5 Prime -sense strand were synthesized. Black-Right-Pointing-Pointer Ar-siRNAs increased resistance against nuclease degradation. Black-Right-Pointing-Pointer Ar-siRNAs were thermodynamically stable compared with the unmodified siRNA. Black-Right-Pointing-Pointer High levels of cellular uptake and cytoplasmic localization were found. Black-Right-Pointing-Pointer Strong gene-silencing efficacy was exhibited in the Ar-siRNAs. -- Abstract: Short interference RNA (siRNA) is a powerful tool for suppressing gene expression in mammalian cells. In this study, we focused on the development of siRNAs conjugated with aromatic compounds in order to improve the potency of RNAi and thus to overcome several problems with siRNAs, such as cellular delivery and nuclease stability. The siRNAs conjugated with phenyl, hydroxyphenyl, naphthyl, and pyrenyl derivatives showed strong resistance to nuclease degradation, and were thermodynamically stable compared with unmodified siRNA. A high level of membrane permeability in HeLa cells was also observed. Moreover, these siRNAs exhibited enhanced RNAi efficacy, which exceeded that of locked nucleic acid (LNA)-modified siRNAs, against exogenous Renilla luciferase in HeLa cells. In particular, abundant cytoplasmic localization and strong gene-silencing efficacy were found in the siRNAs conjugated with phenyl and hydroxyphenyl derivatives. The novel siRNAs conjugated with aromatic compounds are promising candidates for a new generation of modified siRNAs that can solve many of the problems associated with RNAi technology.

  9. Comparative study of aromatic compounds in fruit wines from raspberry, strawberry, and mulberry in central Shaanxi area

    PubMed Central

    Feng, Yiming; Liu, Min; Ouyang, Yanan; Zhao, Xianfang; Ju, Yanlun; Fang, Yulin

    2015-01-01

    Background Although grape wines have firmly dominated the production and consumption markets of fruit wines, raspberry, strawberry, and mulberry have been utilized to make wines because of their joyful aroma and high contents of polyphenolic phytochemicals and essential fatty acids. However, little is known about aromatic compounds of the wines produced from these three fruits. Methods The aromatic composition of fruit wines produced from raspberry, strawberry, mulberry, and red grape was analyzed by GC-MS. Odor activity values (OAVs) and relative odor contributions (ROCs) were used to estimate the sensory contribution of the aromatic compounds to the overall flavor of the wines. Results In strawberry, raspberry, and mulberry wines, 27, 30, and 31 odorants were detected, respectively. Alcohols formed the most abundant group, followed by esters and acids. The grape wine contained a wider variety (16 types) of alcohols, and 4-methyl-2-pentanol and 2,3-butanediol were not present in the three fruit wines. The quantity of esters in raspberry (1.54%) and mulberry wines (2.08%) were higher than those of strawberry wine (0.78%), and mulberry wine contained more types of esters. There were no significant differences of acids between the three fruit wines and the control wine. In addition, 2-heptanone, 2-octanone, 2-nonanone, and 2-undecanone were unique to raspberry wine, and nonanal was present only in mulberry wine. The indistinguishable aroma of the three fruit wines was attributed to the dominance of fruity and floral odor components derived from ethyl esters of fatty acids and their contributions to the global aroma of the three fruit wines. Conclusion The present study demonstrated that there were significant differences in the volatile components of fruit wines made from raspberry, strawberry, and mulberry. The aroma compounds were more abundant in the raspberry and mulberry wines than in the strawberry wine, but the quality of strawberry wine was superior to

  10. The German Environmental Survey 1990/92 (GerES II): sources of personal exposure to volatile organic compounds.

    PubMed

    Hoffmann, K; Krause, C; Seifert, B; Ullrich, D

    2000-01-01

    In the framework of the second German Environmental Survey carried out in the Western part of Germany in 1990/91 (GerES IIa) 113 adults aged 25-69 years were selected at random from the total study population of about 2500 to investigate personal exposure to about 70 volatile organic compounds (VOCs). Each subject wore a diffusive badge-type sampler for 1 week. The VOCs determined included alkanes, aromatics, aliphatic halocarbons, terpenes, and oxygen-containing compounds. Multivariate regression analysis was carried out to determine and quantify the major sources of personal exposure to various VOCs. In this paper, results are given for benzene, and C8- and C9-aromatics. Being subject to environmental tobacco smoke was found to be the most important determinant of benzene exposure, but automobile-related activities such as driving a car or refuelling, were also associated with significantly increased levels of benzene. The major determinant of C8- and C9-aromatics concentrations was occupational exposure. Emissions from paints, lacquers, newspapers, magazines and print-works were also important contributors to C8-aromatics exposure. Renovation, painting and smoking were associated with a significant increase of the exposure to C9-aromatics.

  11. Characterization of polycyclic aromatic compounds in diesel exhaust particulate extract responsible for aryl hydrocarbon receptor activity

    NASA Astrophysics Data System (ADS)

    Soontjens, Carol D.; Holmberg, Kristina; Westerholm, Roger N.; Rafter, Joseph J.

    Chemical fractions of a model diesel exhaust particulate extract, notably the fraction containing polycyclic aromatic hydrocarbons (PAH) (Fraction II), mono-nitro PAH (Fraction III), and dinitro-PAH (Fraction IV) have been shown to displace binding of 2,3,7,8-tetrachloro[1,6-[ 3H

  12. Immunological disorders associated with polychlorinated biphenyls and related halogenated aromatic hydrocarbon compounds

    USGS Publications Warehouse

    Noguchi, G.E.; Leatherland, J.F.; Woo, P.T.K.

    1998-01-01

    This review characterizes immunological disorders in fish associated with the widespread environmental contaminants, polychlorinated biphenyls (PCBs), and related halogenated aromatic hydrocarbons (HAHs). Special attention is devoted to comparing the sensitivity of fish species, identifying sensitive immunological endpoints and postulating mechanisms of action.

  13. Generation of standard gas mixtures of halogenated, aliphatic, and aromatic compounds and prediction of the individual output rates based on molecular formula and boiling point.

    PubMed

    Thorenz, Ute R; Kundel, Michael; Müller, Lars; Hoffmann, Thorsten

    2012-11-01

    In this work, we describe a simple diffusion capillary device for the generation of various organic test gases. Using a set of basic equations the output rate of the test gas devices can easily be predicted only based on the molecular formula and the boiling point of the compounds of interest. Since these parameters are easily accessible for a large number of potential analytes, even for those compounds which are typically not listed in physico-chemical handbooks or internet databases, the adjustment of the test gas source to the concentration range required for the individual analytical application is straightforward. The agreement of the predicted and measured values is shown to be valid for different groups of chemicals, such as halocarbons, alkanes, alkenes, and aromatic compounds and for different dimensions of the diffusion capillaries. The limits of the predictability of the output rates are explored and observed to result in an underprediction of the output rates when very thin capillaries are used. It is demonstrated that pressure variations are responsible for the observed deviation of the output rates. To overcome the influence of pressure variations and at the same time to establish a suitable test gas source for highly volatile compounds, also the usability of permeation sources is explored, for example for the generation of molecular bromine test gases.

  14. Determination of volatile organic and polycyclic aromatic hydrocarbons in crude oil with efficient gas-chromatographic methods.

    PubMed

    Wang, Haijing; Geppert, Helmut; Fischer, Thomas; Wieprecht, Wolfgang; Möller, Detlev

    2015-01-01

    Determination of volatile organic compounds (VOCs) in crude oil, such as super volatile organic compounds (super VOCs) and simple polycyclic aromatic hydrocarbons (PAHs), is vital for targeting crude oil spill spots. In this study, a static headspace gas chromatography flame ionization detection method was established for determination of super VOCs in crude oil with both external and internal standard determination, which can be used in the field when using portable gas chromatography. Identification was done by comparing the retention time with the corresponding standards and quantitation was done with a new one-drop method. Another simplified and efficient method was performed to analyze volatile PAHs in crude oil, which can also be used in field analysis. Toluene was used as the extraction solvent for PAHs in crude oil. Method validation for both analyses was satisfactory. The result showed that n-butane and n-pentane were maximum super VOCs and naphthalene, phenanthrene and fluorene were the main PAHs in the crude oil studied. The super VOCs quantity ranged from 3 to 6% and the main PAHs consisted of 0.02-0.06% of studied crude oil.

  15. Seasonal and diurnal trends in concentrations and fluxes of volatile organic compounds in central London

    NASA Astrophysics Data System (ADS)

    Valach, A. C.; Langford, B.; Nemitz, E.; MacKenzie, A. R.; Hewitt, C. N.

    2015-07-01

    Concentrations and fluxes of seven volatile organic compounds (VOCs) were measured between August and December 2012 at a rooftop site in central London as part of the ClearfLo project (Clean Air for London). VOC concentrations were quantified using a proton transfer reaction mass spectrometer (PTR-MS) and fluxes were calculated using a virtual disjunct eddy covariance technique. The median VOC fluxes, including aromatics, oxygenated compounds and isoprene, ranged from 0.07 to 0.33 mg m-2 h-1. Median mixing ratios were 7.3 ppb for methanol and < 1 ppb for the other compounds. Strong relationships were observed between the fluxes and concentrations of some VOCs with traffic density and between the fluxes and concentrations of isoprene and oxygenated compounds with photosynthetically active radiation (PAR) and temperature. An estimated 50-90 % of the fluxes of aromatic VOCs were attributable to traffic activity, which showed little seasonal variation, suggesting that boundary layer effects or possibly advected pollution may be the primary causes of increased concentrations of aromatics in winter. Isoprene, methanol and acetaldehyde fluxes and concentrations in August and September showed high correlations with PAR and temperature, when fluxes and concentrations were largest suggesting that biogenic sources contributed to their fluxes. Modelled biogenic isoprene fluxes from urban vegetation using the Guenther et al. (1995) algorithm agreed well with measured fluxes in August and September. Comparisons of estimated annual benzene emissions from both the London and the National Atmospheric Emissions Inventories agreed well with measured benzene fluxes. Flux footprint analysis indicated emission sources were localised and that boundary layer dynamics and source strengths were responsible for temporal and spatial VOC flux and concentration variability during the measurement period.

  16. Seasonal trends in concentrations and fluxes of volatile organic compounds above central London

    NASA Astrophysics Data System (ADS)

    Valach, A. C.; Langford, B.; Nemitz, E.; MacKenzie, A. R.; Hewitt, C. N.

    2015-03-01

    Concentrations and fluxes of seven volatile organic compounds (VOCs) were measured between August and December 2012 at a roof-top site in central London as part of the ClearfLo project (Clean Air for London). VOC concentrations were quantified using a proton transfer reaction-mass spectrometer and fluxes were calculated using a virtual disjunct eddy covariance technique. The median VOC fluxes, including aromatics, oxygenated compounds and isoprene, ranged from 0.07 to 0.33 mg m-2 h-1 and mixing ratios were 7.27 ppb for methanol (m / z 33) and <1 ppb for the remaining compounds. Strong relationships were observed between most VOC fluxes and concentrations with traffic density, but also with photosynthetically active radiation (PAR) and temperature for the oxygenated compounds and isoprene. An estimated 50-90 % of aromatic fluxes were attributable to traffic activity, which showed little seasonal variation, suggesting boundary layer effects or possibly advected pollution may be the primary causes of increased concentrations of aromatics in winter. PAR and temperature-dependent processes accounted for the majority of isoprene, methanol and acetaldehyde fluxes and concentrations in August and September, when fluxes and concentrations were largest. Modelled biogenic isoprene fluxes using the G95 algorithm agreed well with measured fluxes in August and September, due to urban vegetation. Comparisons of estimated annual benzene emissions from the London and National Atmospheric Emissions Inventory agreed well with measured benzene fluxes. Flux footprint analysis indicated emission sources were localized and that boundary layer dynamics and source strengths were responsible for temporal and spatial VOC flux and concentration variability during the measurement period.

  17. Spectroscopic characterization of dissolved organic matter derived from different biochars and their polycylic aromatic hydrocarbons (PAHs) binding affinity.

    PubMed

    Tang, Jianfeng; Li, Xinhu; Luo, Yan; Li, Gang; Khan, Sardar

    2016-06-01

    In recent years, biochar has received a great attention due to its high application in different sectors of environment. The feasibility of biochar applications is depended on its physical and chemical properties and biochar-derived dissolved organic matter (DOM) characteristics. This study was conducted to investigate the spectroscopic characteristics of biochar-derived DOM and its binding capacity of hydrophobic organic chemicals (HOCs). DOM solutions were isolated from five different biochars prepared through pyrolysis and analyzed for dissolved organic carbon (DOC) contents. The optical analysis with UV-visible absorption and excitation-emission matrix (EEM) fluorescence spectroscopes and DOC water distribution coefficient (KDOC) were calculated in the presence of PAHs and DOM. The DOC contents and the estimated aromaticity (SUVA254) were different for selected biochars. The DOM derived from soybean straw biochar (SBBC) showed the highest DOC contents followed by rice straw biochar (RSBC). The SBBC and RSBC peak position in the fluorescence excitation/emission matrix at longer wavelength corresponded to the peak position of other three biochars indicating that SBBC and RSBC had relatively higher degree of humification. This was well correlated with the observed KDOC values, suggesting that the KDOC value(')s dominant factor was the degree of biochar-derived DOM humification. The results of this study indicate that the optical analysis may provide valuable information regarding the characteristics of biochar-derived DOM and its application as environmental amendments for minimization of toxic organic compounds.

  18. Evaluation of tetraglyme for the enrichment and analysis of volatile organic compounds in air.

    PubMed

    Huybrechts, T; Dewulf, J; Van Craeynest, K; Van Langenhove, H

    2001-07-13

    A recently developed method for the sampling and analysis of volatile organic compounds in air has been evaluated. The system is based on the enrichment of analytes in tetraethylene glycol dimethyl ether or tetraglyme, a water-soluble organic liquid. The subsequent analysis consists of dispersion of a sample aliquot in water followed by purge-and-trap and gas chromatographic separation. Physico-chemical data were investigated for 10 volatile organic compounds, providing information on the possibilities and limitations of the tetraglyme method. The target analytes included chlorinated alkanes and alkenes, and monocyclic aromatic hydrocarbons. Air/tetraglyme partition coefficients Kat were determined over an environmental relevant temperature range of 2-25 degrees C to evaluate sorption efficiencies and estimate breakthrough volumes at the sampling stage. At 2 degrees C breakthrough volumes (allowing 5% of breakthrough) ranged from 5.8 (1,1-dichloroethane) to 312 l (1,1,2-trichloroethane) for 20 ml of tetraglyme. With regard to the desorption stage, the effect of tetraglyme on the air/water partition of organic compounds was investigated through the measurement of air/tetraglyme-water partition coefficients Kat-w for 2-31% (v/v) tetraglyme in water. Finally a clean-up procedure for tetraglyme was evaluated. Analysis of a blank tetraglyme-water (17:83, v:v) mixture by gas chromatography-flame ionization detection/mass spectrometry showed minor background signals. None of the target compounds were detected.

  19. The impact of drying on structure of sedimentary organic matter in wetlands: Probing with native and amended polycyclic aromatic hydrocarbons.

    PubMed

    Wang, Zucheng; Liu, Zhanfei; Liu, Min; Xu, Kehui; Mayer, Lawrence M

    2016-10-15

    Wetland sediments undergo dry-wet cycles that may change their structural properties and affect geochemical behavior of associated organic compounds. In this study, we examined the effect of drying on particle size distributions and the rapid (24h) sorption reactions of polycyclic aromatic hydrocarbons (PAHs) with salt marsh sediments in Nueces Delta, South Texas. Drying reduced the fraction of fine particles in organically richer sediments, indicating structural rearrangement of organic matter and mineral aggregates. Among the 16 EPA priority PAHs examined, dried sediment preferentially released 1.0-7.5% of phenanthrene, fluoranthene and pyrene to added seawater (solid: water mass ratio of 1/100) - significantly greater than release from sediments maintained in the wet state. On the other hand, drying also increased the affinity of sedimentary organic matter (SOM) for experimentally amended (deuterated) phenanthrene relative to continually wet sediments. Further, deuterated phenanthrene was even more effectively retained when it was added to wet sediment that was subsequently dried and rewetted. These apparently contradictory results can be reconciled and explained by SOM having a heterogeneous distribution of hydrophobic and hydrophilic zones - e.g., a zonal model. We propose that drying changed the orientation of amphiphilic SOM, exposing hydrophobic zones and promoting the release of some of their native PAHs to water. Freshly amended PAHs were only able to penetrate into the surface hydrophobic zone and/or deeper but rapidly accessible ("kinetic") zone in wet sediments due to the brief adsorption contact time. Subsequent drying presumably then induced structural changes in SOM that isolated these amended PAHs in sites inaccessible to water exchange in the next rewetting. These results provide insights into structural changes of SOM upon drying, and help predict the fate of compounds such as organic contaminants during drought/flood oscillations.

  20. Organic compound composition in soil and sediments collected in Jackson, Mississippi.

    PubMed

    Gołębiowski, Marek; Stepnowski, Piotr; Hemmingway, Tometrick; Leszczyńska, Danuta

    2016-01-01

    The aim of our study was to identify organic pollutants found in soil and sediment samples collected within the Jackson, MS metropolitan area. The chemical characterization of the organic compound fractions in soil and sediment samples was carried out by separating the organic fraction using column chromatography (CC) and quantitatively analyzing the polycyclic aromatic hydrocarbons (PAHs), n-alkanes and other organic compounds using gas chromatography-electron impact mass spectrometry (GC-MS). Fifty-six compounds were identified and quantified in the soil samples and 33 compounds were identified and quantified in the sediment samples. The PAHs, n-alkanes and other organic compound profiles in the soil and sediment samples were compared. The percentage contents of the organic compounds in the soil samples were very diverse (from traces to 12.44 ± 1.47%). The compounds present in the highest concentrations were n-alkanes: n-C31 (12.44 ± 1.47%), n-C29 (11.64 ± 1.21%), and n-C33 (8.95 ± 1.08%). The components occurring in smaller quantities (from 1% to 5%) were 2 PAHs (fluoranthene 1.28 ± 0.25%, pyrene 1.16 ± 0.20%), 10 n-alkanes from n-C21 (1.25 ± 0.29%) to n-C32 (2.67 ± 0.52%) and 11 other compounds (e.g., 2-pentanol, 4-methyl (3.33 ± 0.44%), benzyl butyl phthalate (4.25 ± 0.59%), benzenedicarboxylic acid (1.14 ± 0.08%), ethane, 1,1-diethoxy (3.15 ± 0.41) and hexadecanoic acid (2.52 ± 0.34). The soil samples also contained 30 compounds present in concentrations <1% (e.g., anthracene (0.13 ± 0.04%), n-C20 (0.84 ± 0.21%) and acetic acid (0.12 ± 0.04%). The compounds present in the highest concentrations in the sediment samples were PAHs: pyrene (7.73 ± 1.15%) and fluoranthene (6.23 ± 1.07%) and n-alkanes: n-C31 (6.74 ± 1.21%), n-C29 (6.65 ± 0.98%) and n-C27 (6.13 ± 1.09%). The remaining organic compounds were present in smaller quantities (< 5%).