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Sample records for aliphatic aromatic s

  1. Microbial degradation of aliphatic and aliphatic-aromatic co-polyesters.

    PubMed

    Shah, Aamer Ali; Kato, Satoshi; Shintani, Noboru; Kamini, Numbi Ramudu; Nakajima-Kambe, Toshiaki

    2014-04-01

    Biodegradable plastics (BPs) have attracted much attention since more than a decade because they can easily be degraded by microorganisms in the environment. The development of aliphatic-aromatic co-polyesters has combined excellent mechanical properties with biodegradability and an ideal replacement for the conventional nondegradable thermoplastics. The microorganisms degrading these polyesters are widely distributed in various environments. Although various aliphatic, aromatic, and aliphatic-aromatic co-polyester-degrading microorganisms and their enzymes have been studied and characterized, there are still many groups of microorganisms and enzymes with varying properties awaiting various applications. In this review, we have reported some new microorganisms and their enzymes which could degrade various aliphatic, aromatic, as well as aliphatic-aromatic co-polyesters like poly(butylene succinate) (PBS), poly(butylene succinate)-co-(butylene adipate) (PBSA), poly(ε-caprolactone) (PCL), poly(ethylene succinate) (PES), poly(L-lactic acid) (PLA), poly(3-hydroxybutyrate) and poly(3-hydoxybutyrate-co-3-hydroxyvalterate) (PHB/PHBV), poly(ethylene terephthalate) (PET), poly(butylene terephthalate) (PBT), poly(butylene adipate-co-terephthalate (PBAT), poly(butylene succinate-co-terephthalate) (PBST), and poly(butylene succinate/terephthalate/isophthalate)-co-(lactate) (PBSTIL). The mechanism of degradation of aliphatic as well as aliphatic-aromatic co-polyesters has also been discussed. The degradation ability of microorganisms against various polyesters might be useful for the treatment and recycling of biodegradable wastes or bioremediation of the polyester-contaminated environments.

  2. 40 CFR 721.10289 - Hexanedioic acid polymer with aliphatic polyol dihydrogen phosphate aromatic ester (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... aliphatic polyol dihydrogen phosphate aromatic ester (generic). 721.10289 Section 721.10289 Protection of... polymer with aliphatic polyol dihydrogen phosphate aromatic ester (generic). (a) Chemical substance and... acid polymer with aliphatic polyol dihydrogen phosphate aromatic ester (PMN P-11-333) is subject...

  3. 40 CFR 721.10289 - Hexanedioic acid polymer with aliphatic polyol dihydrogen phosphate aromatic ester (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... aliphatic polyol dihydrogen phosphate aromatic ester (generic). 721.10289 Section 721.10289 Protection of... polymer with aliphatic polyol dihydrogen phosphate aromatic ester (generic). (a) Chemical substance and... acid polymer with aliphatic polyol dihydrogen phosphate aromatic ester (PMN P-11-333) is subject...

  4. Neutron Scattering of Aromatic and Aliphatic Liquids

    PubMed Central

    Falkowska, Marta; Bowron, Daniel T.; Manyar, Haresh G.

    2016-01-01

    Abstract Organic solvents, such as cyclohexane, cyclohexene, methylcyclohexane, benzene and toluene, are widely used as both reagents and solvents in industrial processes. Despite the ubiquity of these liquids, the local structures that govern the chemical properties have not been studied extensively. Herein, we report neutron diffraction measurements on liquid cyclohexane, cyclohexene, methylcyclohexane, benzene and toluene at 298 K to obtain a detailed description of the local structure in these compounds. The radial distribution functions of the centres of the molecules, as well as the partial distribution functions for the double bond for cyclohexene and methyl group for methylcyclohexane and toluene have been calculated. Additionally, probability density functions and angular radial distribution functions were extracted to provide a full description of the local structure within the chosen liquids. Structural motifs are discussed and compared for all liquids, referring specifically to the functional group and aromaticity present in the different liquids. PMID:26990367

  5. Biodegradation of aliphatic vs. aromatic hydrocarbons in fertilized arctic soils

    USGS Publications Warehouse

    Braddock, J.F.

    1999-01-01

    A study was carried out to test a simple bioremediation treatment strategy in the Arctic and analyze the influence of fertilization the degradation of aliphatic and aromatic hydrocarbons, e.g., pristine, n-tetradecane, n-pentadecane, 2-methylnaphthalene, naphthalene, and acenaphthalene. The site was a coarse sand pad that once supported fuel storage tanks. Diesel-range organics concentrations were 250-860 mg/kg soil at the beginning of the study. Replicate field plots treated with fertilizer yielded final concentrations of 0, 50, 100, or 200 mg N/kg soil. Soil pH and soil-water potentials decreased due to fertilizer application. The addition of fertilizer considerably increased soil respiration potentials, but not the populations of microorganisms measured. Fertilizer addition also led to ??? 50% loss of measured aliphatic and aromatic hydrocarbons in surface and subsurface soils. For fertilized plots, hydrocarbon loss was not associated with the quantity of fertilizer added. Losses of aliphatic hydrocarbons were ascribed to biotic processes, while losses of aromatic hydrocarbons were due to biotic and abiotic processes.

  6. 40 CFR 721.10289 - Hexanedioic acid polymer with aliphatic polyol dihydrogen phosphate aromatic ester (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Hexanedioic acid polymer with... polymer with aliphatic polyol dihydrogen phosphate aromatic ester (generic). (a) Chemical substance and... acid polymer with aliphatic polyol dihydrogen phosphate aromatic ester (PMN P-11-333) is subject...

  7. Investigation of Aromatic/Aliphatic Polyimides as Dispersants for Single Wall Carbon Nanotubes

    NASA Technical Reports Server (NTRS)

    Delozier, Donavon M.; Watson, Kent A.; Smith, Joseph G., Jr.; Clancy, Thomas C.; Connell, John W.

    2006-01-01

    Novel aromatic/aliphatic polyimides were prepared from 2,7-diamino-9,9'- dioctylfluorene (AFDA) and aromatic dianhydrides. Upon investigating the effectiveness of these polyimides for dispersing single wall carbon nanotubes (SWNTs) in solution, three were discovered to disperse SWNTs in N,N-dimethylacetamide (DMAc). Two of these polyimides, one from 3,3',4,4'-oxydiphthalic anhydride (ODPA) and one from symmetric 3,3',4,4'-biphenyltetracarboxylic dianhydride (s-BPDA), were used to prepare nanocomposites. Homogeneous polyimide/SWNT suspensions from both polymers were used in the preparation of films and fibers containing up to 1 wt% SWNTs. The samples were thermally treated to remove residual solvent and the films were characterized for SWNT dispersion by optical and high resolution scanning electron microscopy (HRSEM). Electrical and mechanical properties of the films were also determined. Electrospun fibers were examined by HRSEM to characterize SWNT alignment and orientation.

  8. A THEORETICAL STUDY ON THE VIBRATIONAL SPECTRA OF POLYCYCLIC AROMATIC HYDROCARBON MOLECULES WITH ALIPHATIC SIDEGROUPS

    SciTech Connect

    Sadjadi, SeyedAbdolreza; Zhang, Yong; Kwok, Sun

    2015-03-01

    The role of aliphatic side groups in the formation of astronomical unidentified infrared emission (UIE) features is investigated by applying the density functional theory to a series of molecules with mixed aliphatic-aromatic structures. The effects of introducing various aliphatic groups to a fixed polycyclic aromatic hydrocarbon (PAH) core (ovalene) are studied. Simulated spectra for each molecule are produced by applying a Drude profile at T = 500 K while the molecule is kept at its electronic ground state. The vibrational normal modes are classified using a semi-quantitative method. This allows us to separate the aromatic and aliphatic vibrations, and therefore provides clues to what types of vibrations are responsible for the emissions bands at different wavelengths. We find that many of the UIE bands are not pure aromatic vibrational bands but may represent coupled vibrational modes. The effects of aliphatic groups on the formation of the 8 μm plateau are quantitatively determined. The vibrational motions of methyl (–CH{sub 3}) and methylene (–CH{sub 2} –) groups can cause the merging of the vibrational bands of the parent PAH and the forming of broad features. These results suggest that aliphatic structures can play an important role in the UIE phenomenon.

  9. 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.

  10. 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.

  11. On the aliphatic versus aromatic content of the carriers of the `unidentified' infrared emission features

    NASA Astrophysics Data System (ADS)

    Yang, X. J.; Glaser, R.; Li, Aigen; Zhong, J. X.

    2016-10-01

    Although it is generally accepted that the unidentified infrared emission (UIE) features at 3.3, 6.2, 7.7, 8.6, and 11.3 μm are characteristic of the stretching and bending vibrations of aromatic hydrocarbon materials, the exact nature of their carriers remains unknown: whether they are free-flying, predominantly aromatic gas-phase molecules, or amorphous solids with a mixed aromatic/aliphatic composition are being debated. Recently, the 3.3 and 3.4 μm features which are commonly respectively attributed to aromatic and aliphatic C-H stretches have been used to place an upper limit of ˜2 per cent on the aliphatic fraction of the UIE carriers (i.e. the number of C atoms in aliphatic chains to that in aromatic rings). Here we further explore the aliphatic versus aromatic content of the UIE carriers by examining the ratio of the observed intensity of the 6.2 μm aromatic C-C feature (I6.2) to that of the 6.85 μm aliphatic C-H deformation feature (I6.85). To derive the intrinsic oscillator strengths of the 6.2 μm stretch (A6.2) and the 6.85 μm deformation (A6.85), we employ density functional theory to compute the vibrational spectra of seven methylated polycyclic aromatic hydrocarbon molecules and their cations. By comparing I6.85/I6.2 with A6.85/A6.2, we derive the fraction of C atoms in methyl(ene) aliphatic form to be at most ˜10 per cent, confirming the earlier finding that the UIE emitters are predominantly aromatic. We have also computed the intrinsic strength of the 7.25 μm feature (A7.25), another aliphatic C-H deformation band. We find that A6.85 appreciably exceeds A7.25. This explains why the 6.85 μm feature is more frequently detected in space than the 7.25 μm feature.

  12. THE CARRIERS OF THE INTERSTELLAR UNIDENTIFIED INFRARED EMISSION FEATURES: AROMATIC OR ALIPHATIC?

    SciTech Connect

    Li Aigen; Draine, B. T. E-mail: draine@astro.princeton.edu

    2012-12-01

    The unidentified infrared emission (UIE) features at 3.3, 6.2, 7.7, 8.6, and 11.3 {mu}m, commonly attributed to polycyclic aromatic hydrocarbon (PAH) molecules, have been recently ascribed to coal- or kerogen-like organic nanoparticles with a mixed aromatic-aliphatic structure. However, we show in this Letter that this hypothesis is inconsistent with observations. We estimate the aliphatic fraction of the UIE carriers based on the observed intensities of the 3.4 {mu}m and 6.85 {mu}m emission features by attributing them exclusively to aliphatic C-H stretch and aliphatic C-H deformation vibrational modes, respectively. We derive the fraction of carbon atoms in aliphatic form to be <15%. We conclude that the UIE emitters are predominantly aromatic, with aliphatic material at most a minor part of the UIE carriers. The PAH model is consistent with astronomical observations and PAHs dominate the strong UIE bands.

  13. Folding and self-assembly of aromatic and aliphatic urea oligomers: towards connecting structure and function.

    PubMed

    Fischer, Lucile; Guichard, Gilles

    2010-07-21

    Folding and self-assembly of biomacromolecules has inspired the development of discrete, non-natural oligomers that fold and/or self-assemble in a controlled manner. Though aromatic and aliphatic oligoamides remain unmatched for structural diversity and synthetic versatility, oligomers based on amide bond surrogates, such as urea backbones, also demonstrated a propensity for folding and self-assembly. In this Perspective, we review the advances in the design of oligomeric aromatic and aliphatic urea sequences (essentially N,N'-linked) that fold and/or self-assemble. Whenever applicable, the relationship between structure and function will be highlighted.

  14. 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.

  15. SELECTIVE ENUMERATION OF AROMATIC AND ALIPHATIC HYDROCARBON DEGRADING BACTERIA BY A MOST-PROBABLE-NUMBER PROCEDURE

    EPA Science Inventory

    A most-portable-number (MPN) procedure was developed to separately enumerate aliphatic and aromatic hydrocarbon degrading bacteria, because most of the currently available methods are unable to distinguish between these two groups. Separate 96-well microtiter plates are used to ...

  16. 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.

  17. Aromatic and aliphatic CH hydrogen bonds fight for chloride while competing alongside ion pairing within triazolophanes.

    PubMed

    Hua, Yuran; Ramabhadran, Raghunath O; Uduehi, Esther O; Karty, Jonathan A; Raghavachari, Krishnan; Flood, Amar H

    2011-01-03

    Triazolophanes are used as the venue to compete an aliphatic propylene CH hydrogen-bond donor against an aromatic phenylene one. Longer aliphatic C-H...Cl(-) hydrogen bonds were calculated from the location of the chloride within the propylene-based triazolophane. The gas-phase energetics of chloride binding (ΔG(bind) , ΔH(bind) , ΔS(bind) ) and the configurational entropy (ΔS(config) ) were computed by taking all low-energy conformations into account. Comparison between the phenylene- and propylene-based triazolophanes shows the computed gas-phase free energy of binding decreased from ΔG(bind) =-194 to -182 kJ mol(-1) , respectively, with a modest enthalpy-entropy compensation. These differences were investigated experimentally. An (1) H NMR spectroscopy study on the structure of the propylene triazolophane's 1:1 chloride complex is consistent with a weaker propylene CH hydrogen bond. To quantify the affinity differences between the two triazolophanes in dichloromethane, it was critical to obtain an accurate binding model. Four equilibria were identified. In addition to 1:1 complexation and 2:1 sandwich formation, ion pairing of the tetrabutylammonium chloride salt (TBA(+) ⋅Cl(-) ) and cation pairing of TBA(+) with the 1:1 triazolophane-chloride complex were observed and quantified. Each complex was independently verified by ESI-MS or diffusion NMR spectroscopy. With ion pairing deconvoluted from the chloride-receptor binding, equilibrium constants were determined by using (1) H NMR (500 μM) and UV/Vis (50 μM) spectroscopy titrations. The stabilities of the 1:1 complexes for the phenylene and propylene triazolophanes did not differ within experimental error, ΔG=(-38±2) and (-39±1) kJ mol(-1) , respectively, as verified by an NMR spectroscopy competition experiment. Thus, the aliphatic CH donor only revealed its weaker character when competing with aromatic CH donors within the propylene-based triazolophane.

  18. Exploring mild enzymatic sustainable routes for the synthesis of bio-degradable aromatic-aliphatic oligoesters.

    PubMed

    Pellis, Alessandro; Guarneri, Alice; Brandauer, Martin; Acero, Enrique Herrero; Peerlings, Henricus; Gardossi, Lucia; Guebitz, Georg M

    2016-05-01

    The application of Candida antarctica lipase B in enzyme-catalyzed synthesis of aromatic-aliphatic oligoesters is here reported. The aim of the present study is to systematically investigate the most favorable conditions for the enzyme catalyzed synthesis of aromatic-aliphatic oligomers using commercially available monomers. Reaction conditions and enzyme selectivity for polymerization of various commercially available monomers were considered using different inactivated/activated aromatic monomers combined with linear polyols ranging from C2 to C12 . The effect of various reaction solvents in enzymatic polymerization was assessed and toluene allowed to achieve the highest conversions for the reaction of dimethyl isophthalate with 1,4-butanediol and with 1,10-decanediol (88 and 87% monomer conversion respectively). Mw as high as 1512 Da was obtained from the reaction of dimethyl isophthalate with 1,10-decanediol. The obtained oligomers have potential applications as raw materials in personal and home care formulations, for the production of aliphatic-aromatic block co-polymers or can be further functionalized with various moieties for a subsequent photo- or radical polymerization.

  19. The influence of chemical composition of aliphatic-aromatic copolyesters on their properties

    NASA Astrophysics Data System (ADS)

    Wojtczak, Malgorzata; Galeski, Andrzej; Dutkiewicz, Slawomir; Piorkowska, Ewa

    2014-05-01

    The chain microstructure and properties of a series of aliphatic-aromatic copolyesters in a range of compositions from 10 to 100% of aromatic components were studied by examining melting and crystallization behaviors, dynamic mechanical response, morphology, wide- (WAXS) and small-angle X-ray scattering (SAXS), and tensile deformation. Chain microstructure was analyzed by 1H NMR. The results indicate that most of copolyesters used in this study have essentially random distribution of comonomers. Copolyesters with more than 30 mol% of aromatic part crystallize with a crystal structure characteristic for homopolymer poly(butylene terephthalate) (PBT). However, some of the reflections from crystal planes are shifted towards lower diffraction angles as compared to butylene terephthalate homoplymer. The phase transition temperatures decrease with increasing aliphatic content. By means of polarized light microscopy (PLM), small-angle light scattering (SALS) and SAXS, crystallization behavior of a selected aliphatic-aromatic copolyester was further explored. Selected copolyester crystallizes in the form of thin fibrous crystals, few nanometers thick, which is the main factor influencing the depression of its melting temperature.

  20. The influence of chemical composition of aliphatic-aromatic copolyesters on their properties

    SciTech Connect

    Wojtczak, Malgorzata; Galeski, Andrzej; Piorkowska, Ewa; Dutkiewicz, Slawomir

    2014-05-15

    The chain microstructure and properties of a series of aliphatic-aromatic copolyesters in a range of compositions from 10 to 100% of aromatic components were studied by examining melting and crystallization behaviors, dynamic mechanical response, morphology, wide- (WAXS) and small-angle X-ray scattering (SAXS), and tensile deformation. Chain microstructure was analyzed by {sup 1}H NMR. The results indicate that most of copolyesters used in this study have essentially random distribution of comonomers. Copolyesters with more than 30 mol% of aromatic part crystallize with a crystal structure characteristic for homopolymer poly(butylene terephthalate) (PBT). However, some of the reflections from crystal planes are shifted towards lower diffraction angles as compared to butylene terephthalate homoplymer. The phase transition temperatures decrease with increasing aliphatic content. By means of polarized light microscopy (PLM), small-angle light scattering (SALS) and SAXS, crystallization behavior of a selected aliphatic-aromatic copolyester was further explored. Selected copolyester crystallizes in the form of thin fibrous crystals, few nanometers thick, which is the main factor influencing the depression of its melting temperature.

  1. SPITZER'S VIEW ON AROMATIC AND ALIPHATIC HYDROCARBON EMISSION IN HERBIG Ae STARS

    SciTech Connect

    Acke, B.; Waters, L. B. F. M.; Bouwman, J.; Juhasz, A.; Henning, Th.; Van den Ancker, M. E.; Meeus, G.; Tielens, A. G. G. M.

    2010-07-20

    The chemistry of astronomical hydrocarbons, responsible for the well-known infrared emission features detected in a wide variety of targets, remains enigmatic. Here we focus on the group of young intermediate-mass Herbig Ae stars. We have analyzed the aliphatic and polycyclic aromatic hydrocarbon (PAH) emission features in the infrared spectra of a sample of 53 Herbig Ae stars, obtained with the Infrared Spectrograph aboard the Spitzer Space Telescope. We confirm that the PAH-to-stellar luminosity ratio is higher in targets with a flared dust disk. However, a few sources with a flattened dust disk still show relatively strong PAH emission. Since PAH molecules trace the gas disk, this indicates that gas disks may still be flared, while the dust disk has settled due to grain growth. There are indications that the strength of the 11.3 {mu}m feature also depends on dust disk structure, with flattened disks being less bright in this feature. We confirm that the CC bond features at 6.2 and 7.8 {mu}m shift to redder wavelengths with decreasing stellar effective temperature. Moreover, we show that this redshift is accompanied by a relative increase of aliphatic CH emission and a decrease of the aromatic 8.6 {mu}m CH feature strength. Cool stars in our sample are surrounded by hydrocarbons with a high aliphatic/aromatic CH ratio and a low aromatic CH/CC ratio, and vice versa for the hot stars. We conclude that, while the overall hydrocarbon emission strength depends on the dust disk's geometry, the relative differences seen in the IR emission features in disks around Herbig Ae stars are mainly due to chemical differences of the hydrocarbon molecules induced by the stellar UV field. Strong UV flux reduces the aliphatic component and emphasizes the spectral signature of the aromatic molecules in the IR spectra.

  2. The effect of aliphatic fuel constituents on the biodegradation of polycyclic aromatic hydrocarbons

    SciTech Connect

    Gamerdinger, A.P.

    1995-12-01

    In petroleum-derived waste, n-alkanes are often codeposited with polycyclic aromatic hydrocarbons (PAHs). The impact of aliphatic fuel constituents on the biodegradation of the more toxic PAHs is considered. Biodegradation of naphthalene by a Coryneform bacteria was examined in biphasic, slurry systems containing and aliphatic solvent in addition to the aqueous phase. The effect of solvent hydrophobicity was evaluated by varying the solvent treatment; a homologous series of n-alkanes was used. Relative to an aqueous system (no solvent), the extent of naphthalene degradation was enhanced in the presence of decane, dodecane, and hexadecane. Biodegradation was apparent, but decreased in the presence of octane, and was completely absent in the presence of hexane. The impact of aliphatic constituents on PAH biodegradation is a function of solvent hydrophobicity. The results indicate that the presence of multiple chemical constituents in complex systems modifies bioavailability and biodegradation.

  3. 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

  4. 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.

  5. Novel synthetic method for the preparation of amphiphilic hyaluronan by means of aliphatic aromatic anhydrides.

    PubMed

    Huerta-Angeles, Gloria; Bobek, Martin; Příkopová, Eva; Šmejkalová, Daniela; Velebný, Vladimír

    2014-10-13

    The present work describes a novel and efficient method of synthesis of amphiphilic hyaluronan (HA) by esterification with alkyl fatty acids. These derivatives were synthesized under mild aqueous and well controlled conditions using mixed aliphatic aromatic anhydrides. These anhydrides characterized by the general formula RCOOCOC6H2Cl3 can be easily prepared by the reaction of the corresponding fatty acid (R) with 2,4,6-trichlorobenzoyl chloride (TCBC) in the presence of triethylamine. The aliphatic aromatic anhydrides RCOOCOC6H2Cl3 then react with the polysaccharide and enable the synthesis of aliphatic acid esters of HA in good yields. No hydrolytic degradation of hyaluronic acid could be observed. Parameters controlling the degree of esterification were systematically studied. Fatty acids with different chain lengths can be introduced applying this methodology. The degree of substitution was decreasing with increasing length of hydrophobic chain. The reaction products were fully characterized by Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance (NMR), SEC-MALLS and chromatographic analyses. Although the esterified HA products exhibited aggregation in solution as demonstrated by NMR, microscopy and rheology, they were still water-soluble.

  6. 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

    We present a quantitative analysis of the hydrocarbon and other organic molecular inventory as a component of the low-albedo material of Saturn’s satellite Iapetus, based on a revision of the calibration of the Cassini VIMS instrument. Our study uses hyperspectral data from a mosaic of Iapetus’ surface (Pinilla-Alonso, N., Roush, T.L., Marzo, G.A., Cruikshank, D.P., Dalle Ore, C.M. [2011]. Icarus 215, 75-82) constructed from VIMS data on a close fly-by of the satellite. We extracted 2235 individual spectra of the low-albedo regions, and with a clustering analysis tool (Dalle Ore, C.M., Cruikshank, D.P., Clark, R.N. [2012]. Icarus 221, 735-743), separated them into two spectrally distinct groups, one concentrated on the leading hemisphere of Iapetus, and the other group on the trailing. This distribution is broadly consistent with that found from Cassini ISS data analyzed by Denk et al. (Denk, T. et al. [2010]. Science 327, 435-439). We modeled the average spectra of the two geographic regions using the materials and techniques described by Clark et al. (Clark, R.N., Cruikshank, D.P., Jaumann, R., Brown, R.H., Stephan, K., Dalle Ore, C.M., Livio, K.E., Pearson, N., Curchin, J.M., Hoefen, T.M., Buratti, B.J., Filacchione, G., Baines, K.H., Nicholson, P.D. [2012]. Icarus 218, 831-860), and after dividing the Iapetus spectrum by the model for each case, we extracted the resulting spectra in the interval 2.7-4.0 μm for analysis of the organic molecular bands. The spectra reveal the Csbnd H stretching modes of aromatic hydrocarbons at ∼3.28 μm (∼3050 cm-1), plus four blended bands of aliphatic sbnd CH2sbnd and sbnd CH3 in the range ∼3.36-3.52 μm (∼2980-2840 cm-1). In these data, the aromatic band, probably indicating the presence of polycyclic aromatic hydrocarbons (PAH), is unusually strong in comparison to the aliphatic bands, as was found for Hyperion (Dalton, J.B., Cruikshank, D.P., Clark, R.N. [2012]. Icarus 220, 752-776; Dalle Ore, C.M., Cruikshank

  7. Aliphatic and aromatic hydrocarbons in different sized aerosols over the Mediterranean Sea: Occurrence and origin

    NASA Astrophysics Data System (ADS)

    Sicre, M. A.; Marty, J. C.; Saliot, A.; Aparicio, X.; Grimalt, J.; Albaiges, J.

    Marine aerosols were collected using a five-stage cascade impactor during the PHYCEMED II cruise in the Western Mediterranean Sea (October 1983). Their composition in aliphatic and aromatic hydrocarbons (HCs) was analyzed, representing the first time that concentrations of polynuclear aromatic HCs (PAH) are reported in relation to particle size for aerosols of remote marine areas. The HC concentrations were found to be dependent on the origin of the air masses. They were higher for air coming from North European countries than for air originating in the Atlantic and the South of Spain. The concentrations range between 7 and 14 ng m -3for n-alkanes and between 0.2 and 0.4 ng m -3for total PAH. Based on molecular criteria, several sources for these HCs have been identified: continental higher plant waxes, petroleum and pyrolysis (namely coal combustion and vehicular exhausts). Mass medium equivalent diameters (MMED) for the naturally derived n-alkanes are in the 1.79-2.53 μm range, indicating an origin related with the emission of large particles from higher plant waxes or from soil dusts. In contrast, MMED for the anthropogenic HCs, both aliphatic and aromatic, are smaller than the micron, suggesting initial emission of PAH through pyrolytic processes in the vapor phase followed by condensation onto larger sub-μm particles.

  8. Aliphatic and polycyclic aromatic hydrocarbons in sediments of Kaohsiung Harbour and Adjacent Coast, Taiwan.

    PubMed

    Lee, Chon-Lin; Hsieh, Ming-Tsuen; Fang, Meng-Der

    2005-01-01

    Surficial sediment samples collected from Kaohsiung Harbour and its nearby coast were analyzed for aliphatic hydrocarbons and parent polycyclic aromatic hydrocarbons (PAHs). According to our results, the average total concentrations of n-alkanes (n-C12 to C35) and aromatics (15 PAHs) were 4.33 microg g(-1) dry weight (ranged 0.46-22.60) and 0.59 microg g(-1) dry weight (ranged 0.09-1.75), respectively. The highest concentrations of aliphatic and aromatic hydrocarbons were recorded in stations near the estuaries of Qianzhen River and Love River, respectively. Aliphatic hydrocarbons in the samples indicate that there has been significant non-petrogenic, possibly terrestrial, contribution in the sediment of the open coast of Kaohsiung Harbour and that there has been dominant contribution from petrogenic sources in the sediment of the inner harbour. PAHs, detected in the samples, however, indicated a higher pyrolytic contribution in open-coast samples and a higher petrogenic contribution in the inner harbour. Overall, sediment concentrations of total alkanes in this study were comparable to those found in Victoria Harbour, Hong Kong and are higher than those found in Xiamen Harbour, China. Concentrations of total PAHs in inner Kaohsiung Harbour sediments were relatively lower than those found in Victoria Harbour, Hong Kong and Xiamen Harbour, China, but comparable to those found in Hsin-ta Harbour, Taiwan and Incheon Harbour, Korea. In comparison with several effect-based sediment quality guidelines, most PAH concentrations found in samples taken from inner harbour stations exceeded the Threshold Effect Level of Florida indicating a slight possibility of adverse effects.

  9. 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.

  10. Exploring 3D structural influences of aliphatic and aromatic chemicals on α-cyclodextrin binding.

    PubMed

    Linden, Lukas; Goss, Kai-Uwe; Endo, Satoshi

    2016-04-15

    Binding of solutes to macromolecules is often influenced by steric effects caused by the 3D structures of both binding partners. In this study, the 1:1 α-cyclodextrin (αCD) binding constants (Ka1) for 70 organic chemicals were determined to explore the solute-structural effects on the αCD binding. Ka1 was measured using a three-part partitioning system with either a headspace or a passive sampler serving as the reference phase. The Ka1 values ranged from 1.08 to 4.97 log units. The results show that longer linear aliphatic chemicals form more stable complexes than shorter ones, and that the position of the functional group has a strong influence on Ka1, even stronger than the type of the functional group. Comparison of linear and variously branched aliphatic chemicals indicates that having a sterically unhindered alkyl chain is favorable for binding. These results suggest that only one alkyl chain can enter the binding cavity. Relatively small aromatic chemicals such as 1,3-dichlorobenzene bind to αCD well, while larger ones like tetrachlorobenzene and 3-ring aromatic chemicals show only a weak interaction with αCD, which can be explained by cavity exclusion. The findings of this study help interpret cyclodextrin binding data and facilitate the understanding of binding processes to macromolecules.

  11. Effect of testosterone and its aliphatic and aromatic dimers on DNA morphology.

    PubMed

    Chanphai, P; Agudelo, D; Vesper, A R; Bérubé, G; Tajmir-Riahi, H A

    2017-02-01

    Conjugation of DNA with testosterone and it aliphatic dimer (alip) and aromatic dimer (arom) was investigated in aqueous solution at pH 7.4. Multiple spectroscopic methods, transmission electron microscopy (TEM) and molecular modeling were used to characterize steroid-DNA binding and DNA morphology. Spectroscopic analysis showed that testosterone binds DNA via A7, A16, A17, T8, T15 and T18 nucleobases with overall binding constants Ktest-DNA=1.8 (±0.4)×10(4)M(-1), Ktest-dimeralip-DNA=5.7 (±0.7)×10(4)M(-1) and Ktest-dimer-arom-DNA=7.3 (±0.9)×10(4)M(-1). The binding affinity increases in this order: testosterone dimer-aromatic>testosterone dimer-aliphatic>testosterone. The steroid loading efficacy was 40-50%. Transmission electron microscopy showed major changes in DNA morphology as testosterone-DNA interaction occurred with increase in the diameter of the DNA aggregate, indicating encapsulation of testosterone by DNA. Modeling showed the presence of several nucleobases attached to testosterone with the free binding energy of -4.93Kcal/mol.

  12. The FEMA GRAS assessment of aliphatic and aromatic terpene hydrocarbons used as flavor ingredients.

    PubMed

    Adams, T B; Gavin, C Lucas; McGowen, M M; Waddell, W J; Cohen, S M; Feron, V J; Marnett, L J; Munro, I C; Portoghese, P S; Rietjens, I M C M; Smith, R L

    2011-10-01

    This publication is the thirteenth in a series of safety evaluations performed by the Expert Panel of the Flavor and Extract Manufacturers Association (FEMA). In 1993, the Panel initiated a comprehensive program to re-evaluate the safety of more than 1700 GRAS flavoring substances under conditions of intended use. Since then, the number of flavoring substances has grown to more than 2600 substances. Elements that are fundamental to the safety evaluation of flavor ingredients include exposure, structural analogy, metabolism, pharmacokinetics and toxicology. Flavor ingredients are evaluated individually and in the context of the available scientific information on the group of structurally related substances. Scientific data relevant to the safety evaluation of the use of aliphatic and aromatic terpene hydrocarbons as flavoring ingredients are evaluated. The group of aliphatic and aromatic terpene hydrocarbons was reaffirmed as GRAS (GRASr) based, in part, on their self-limiting properties as flavoring substances in food; their rapid absorption, metabolic detoxication, and excretion in humans and other animals; their low level of flavor use; the wide margins of safety between the conservative estimates of intake and the no-observed-adverse effect levels determined from subchronic and chronic studies and the lack of significant genotoxic potential.

  13. Encapsulation of testosterone and its aliphatic and aromatic dimers by milk beta-lactoglobulin.

    PubMed

    Chanphai, P; Vesper, A R; Bekale, L; Bérubé, G; Tajmir-Riahi, H A

    2015-05-01

    The encapsulation of testosterone and it aliphatic dimer (alip) and aromatic dimer (arom) with milk β-lactoglobulin (β-LG) was studied in aqueous solution at pH 7.4. Multiple spectroscopic methods, transmission electron microscopy (TEM) and molecular modeling were used to characterize testosterone-β-LG binding and protein aggregation process. Spectroscopic analysis showed that steroids bind β-LG via hydrophobic and H-bonding interactions with overall binding constants K test-β-LG = 5.6 (± 0.6) × 10(4)M(-1), K test-dimeralip-β-LG = 4.8 (± 0.5) × 10(3)M(-1) and K test-dimer-arom-β-LG = 2.9 (± 0.4) × 10(4)M(-1). The binding affinity was testosterone > testosterone dimer-aromatic > testosterone dimer-aliphatic. Transmission electron microscopy showed major changes in protein morphology as testosterone-protein complexation occurred with increase in the diameter of the protein aggregate indicating encapsulation of steroids by β-LG. Modeling showed the presence of H-bonding stabilized testosterone-β-LG complexes with the free binding energy of -9.82 Kcal/mol indicating that the interaction process is spontaneous at room temperature.

  14. Transient-state and steady-state kinetics of the oxidation of aliphatic and aromatic thiols by horseradish peroxidase.

    PubMed

    Burner, U; Obinger, C

    1997-07-14

    In the course of oxidation of thiols by peroxidases thiyl radicals are formed which are known to undergo several free-radical conjugative reactions, among others leading to hydrogen peroxide formation. The present paper for the first time presents a comparative transient-state and steady-state investigation of the reaction of 15 aliphatic and aromatic mono- and dithiols with horseradish peroxidase (HRP). Both sequential-stopped-flow spectrophotometric investigations of the reaction of HRP intermediates Compound I (k2) and Compound II (k3) with thiols and measurements of the overall thiol oxidation and the simultaneous oxygen consumption in the presence and absence of exogenously added hydrogen peroxide (10 microM) have been performed. With HRP as thiyl radical generator it was shown that three groups of thiols have to be distinguished: (i) Aromatic thiols (e.g. thiophenol, 2-mercaptopurine) were excellent electron donors of both Compounds (k2: 10(4)-10(7) M(-1) s(-1) and k3: 10(3)-10(6) M(-1) s(-1)); however, the overall reaction was shown to depend on addition of hydrogen peroxide, indicating insufficient peroxide regeneration by arylthiyl radicals. (ii) Aliphatic thiols which were extremely bad substrates (k3 < 10 M(-1) s(-1)) for HRP (e.g. homocysteine, glutathione) and/or have a pK(a,SH) > 9.5 (e.g. N-acetylcysteine, alpha-lipoic acid) were also shown to depend on exogenously added H2O2 to maintain the peroxidasic reaction, whereas (iii) with those thiols with rates of k3 between 11 and 1600 M(-1) s(-1) (e.g. cysteine, cysteamine, cysteine methyl ester, cysteine ethyl ester) and/or with a pK(a,SH) < 8 (penicillamine) thiol oxidation was independent of exogenously added hydrogen peroxide, indicating sufficient hydrogen peroxide regeneration.

  15. Aliphatic and polycyclic aromatic hydrocarbons characterisation of Coimbra and Oporto PM2.5 urban aerosol

    NASA Astrophysics Data System (ADS)

    Rocha, A. C.; Mirante, F.; Gonçalves, C.; Nunes, T.; Alves, C.; Evtyugina, M.; Kowacz, M.; Pio, C.; Rocha, C.; Vasconcelos, T.

    2009-04-01

    The concentration of organic pollutants in urban areas is mostly due to incomplete combustion from vehicles, industries and domestic heating. Some of these compounds, principally the aliphatic (ALIPH) and polycyclic aromatic hydrocarbons (PAHs) promote harmful effects in human health. The determination of the ALIPH and PAHs concentration levels and their possible emission sources are useful for air quality management and source apportionment studies. In order to estimate and compare the ambient concentrations and establish the main sources of these compounds, the fine fraction of the atmospheric particulate matter (PM2.5) was collected simultaneously in Oporto and Coimbra during summer and winter seasons using a high volume sampler. The organic compounds were extracted from the particulate matter, under reflux with dichloromethane and the total organic extract (TOE) was fractionated by flash chromatography using five different eluents with increasing polarity. The hydrocarbon fractions were analysed by gas chromatography/mass spectrometry (GC/MS). Here we present and discuss the qualitative and quantitative composition of the aliphatic and aromatic fractions present in PM2.5 samples from both cities. The homologous series of C14 to C34 n-alkanes, isoprenoid hydrocarbons (pristane and phytane), PAHs and some petroleum markers have been identified and quantified. With the purpose of identifying the possible sources, various molecular diagnostic ratios were calculated. The global carbon preference index (CPI) closer to the unity, the large concentration of the unresolved complex mixture (UCM) and the presence of PAHs indicate that motor vehicle exhaust was the main emission source of the aliphatic and polycyclic aromatic fractions of Oporto and Coimbra aerosol, especially in the first city. Also, the remarkable presence of petroleum biomarkers such, as hopanes, confirms the previous results. Concentration ratios between PAHs were calculated and used to assign emission

  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. Visual Recognition of Aliphatic and Aromatic Amines Using a Fluorescent Gel: Application of a Sonication-Triggered Organogel.

    PubMed

    Pang, Xuelei; Yu, Xudong; Lan, Haichuang; Ge, Xiaoting; Li, Yajuan; Zhen, Xiaoli; Yi, Tao

    2015-06-24

    A naphthalimide-based fluorescent gelator (N1) containing an alkenyl group has been designed and characterized. This material is able to gelate alcohols via a precipitate-to-gel transformation when triggered with ultrasound for less than 2 min (S-gel). The gelation process in n-propanol was studied by means of absorption, fluorescence, and IR spectra, scanning electron microscopy (SEM) images, and X-ray diffraction patterns. The fluorescence intensity of N1 decreased during the gelation process in a linear relationship with the sonication time. The S-gel of N1 could be used to sense aliphatic and aromatic amines by measuring the change in the signal output. For example, the addition of propylamine to the S-gel of N1 resulted in a dramatic enhancement of the fluorescence intensity, accompanied by a gel-to-sol transition. On the contrary, when the S-gel of N1 was treated with aromatic amines such as aniline, fluorescence was quenched and there was no gel collapse. The sensing mechanisms were studied by (1)H NMR, small-angle X-ray scattering, SEM and spectroscopic experiments. It is proposed that isomerization of the alkenyl group of N1 from the trans to cis form occurs when the S-gel is treated with propylamine, resulting in a gel-sol transition. However, the aromatic aniline molecules prefer to insert into the gel networks of N1 via hydrogen-bonding and charge-transfer interactions, maintaining the gel state. As potential applications, testing strips of N1 were prepared to detect aniline.

  18. Asphaltene adsorption onto self-assembled monolayers of mixed aromatic and aliphatic trichlorosilanes.

    PubMed

    Turgman-Cohen, Salomon; Smith, Matthew B; Fischer, Daniel A; Kilpatrick, Peter K; Genzer, Jan

    2009-06-02

    The adsorption of asphaltenes onto flat solid surfaces modified with mixed self-assembled monolayers (SAMs) of aliphatic and aromatic trichlorosilanes with varying wettabilities, aromaticities, and thicknesses is tested. The mixed SAMs are characterized by means of contact angle to assess hydrophobicity and molecular and chemical uniformity, spectroscopic ellipsometry to measure the thickness of the films, and near edge X-ray absorption fine structure (NEXAFS) spectroscopy to assess chemical and molecular composition. The molecular characteristics of the adsorbed asphaltene layer and the extent of asphaltene adsorption are determined using NEXAFS and spectroscopic ellipsometry, respectively. The SAMs are formed by depositing phenyl-, phenethyl-, butyl-, and octadecyl- trichlorosilanes from toluene solutions onto silica-coated substrates; the chemical composition and the wettability of the SAM surface is tuned systematically by varying the trichlorosilane composition in the deposition solutions. The adsorption of asphaltenes on the substrates does not correlate strongly with the SAM chemical composition. Instead, the extent of asphaltene adsorption decreases with increasing SAM thickness. This observation suggests that the leading interaction governing the adsorption of asphaltenes is their interaction with the polar silica substrate and that the chemical composition of the SAM is of secondary importance.

  19. Aliphatic and polycyclic aromatic hydrocarbons in the surface sediments of the Mediterranean: assessment and source recognition of petroleum hydrocarbons.

    PubMed

    El Nemr, Ahmed; El-Sadaawy, Manal M; Khaled, Azza; Draz, Suzanne O

    2013-06-01

    Coastal marine sediment samples were collected from ten sampling stations along the Egyptian Mediterranean coast in April 2010. All sediment samples were analyzed for aliphatic (C7 to C34) and polycyclic aromatic hydrocarbons (PAHs) as well as total organic carbon (TOC) contents and grain size analysis. Total aliphatic hydrocarbons ranged from 1621.82 to 9069.99 ng/g (dry weight), while aromatic hydrocarbons (16 PAHs) varied between 208.69 and 1020.02 ng/g with an average of 530.68 ± 225.86 ng/g dwt. Good correlations observed between certain PAH concentrations allowed to identify its origin. The average TOC percent was varied from 0.13 to 1.46 %. Principal component analysis was used to determine the sources of hydrocarbon pollutants in sediments of Mediterranean. Additionally, special PAHs compound ratios suggest the petrogenic origins.

  20. Continuous-flow synthesis of primary amines: Metal-free reduction of aliphatic and aromatic nitro derivatives with trichlorosilane

    PubMed Central

    Porta, Riccardo; Colombo, Giacomo; Rossi, Sergio

    2016-01-01

    The metal-free reduction of nitro compounds to amines mediated by trichlorosilane was successfully performed for the first time under continuous-flow conditions. Aromatic as well as aliphatic nitro derivatives were converted to the corresponding primary amines in high yields and very short reaction times with no need for purification. The methodology was also extended to the synthesis of two synthetically relevant intermediates (precursors of baclofen and boscalid). PMID:28144331

  1. A Low Field Fluorine-Electron Double Resonance Study for GALV and BDPA in Some Aliphatic and Aromatic Solvents

    NASA Astrophysics Data System (ADS)

    Peksoz, Ahmet; Yalciner, Aytac; Cimenoglu, Mehmet Akif

    2009-08-01

    Dynamic nuclear polarization experiments were performed to study the solutions of the stable free radicals Galvinoxyl and α,γ -Bisdiphenylene-β -phenyl allyl complex with benzene (1 : 1) in some highly fluorinated aliphatic and aromatic solvents. The measurements were performed at four different temperatures to test the dipolar and the scalar part of the coupling between the fluorine nucleus (19F) and the unpaired electron. It was found that in the samples with Galvinoxyl the dipolar interactions are more effective for the aromatic solvents, while the scalar interactions are more effective for the aliphatics. An alteration from negative to positive region for the nuclear-electron coupling parameter informing on scalar or dipole-dipole interaction was observed only for 2,2,3,4,4,4-Hexafluoro- 1-butanol solvent with increasing temperature. The nuclear-electron coupling parameter varies between -0.003 and 0.228 in all aliphatic solvents and between 0.180 and 0.318 in aromatic solvents. Overhauser enhancement was not observed in the samples prepared with Hexadecafluoroheptane, Heptafluorobutyric acid, and Nonafluoropentanoic acid for both free radicals in all temperatures. These solvents may have scavenging effects on the radicals due to their behaviour.

  2. Polycyclic Aromatic Hydrocarbons with Aliphatic Sidegroups: Intensity Scaling for the C–H Stretching Modes and Astrophysical Implications

    NASA Astrophysics Data System (ADS)

    Yang, X. J.; Li, Aigen; Glaser, R.; Zhong, J. X.

    2017-03-01

    The so-called unidentified infrared emission (UIE) features at 3.3, 6.2, 7.7, 8.6, and 11.3 μ {{m}} ubiquitously seen in a wide variety of astrophysical regions are generally attributed to polycyclic aromatic hydrocarbon (PAH) molecules. Astronomical PAHs may have an aliphatic component, as revealed by the detection in many UIE sources of the aliphatic C–H stretching feature at 3.4 μ {{m}}. The ratio of the observed intensity of the 3.4 μ {{m}} feature to that of the 3.3 μ {{m}} aromatic C–H feature allows one to estimate the aliphatic fraction of the UIE carriers. This requires knowledge of the intrinsic oscillator strengths of the 3.3 μ {{m}} aromatic C–H stretch ({A}3.3) and the 3.4 μ {{m}} aliphatic C–H stretch ({A}3.4). Lacking experimental data on {A}3.3 and {A}3.4 for the UIE candidate materials, one often has to rely on quantum-chemical computations. Although the second-order Møller–Plesset (MP2) perturbation theory with a large basis set is more accurate than the B3LYP density functional theory, MP2 is computationally very demanding and impractical for large molecules. Based on methylated PAHs, we show here that, by scaling the band strengths computed at an inexpensive level (e.g., B3LYP/6-31G*), we are able to obtain band strengths as accurate as those computed at far more expensive levels (e.g., MP2/6-311+G(3df,3pd)). We calculate the model spectra of methylated PAHs and their cations excited by starlight of different spectral shapes and intensities. We find that {({I}3.4/{I}3.3)}{mod}, the ratio of the model intensity of the 3.4 μ {{m}} feature to that of the 3.3 μ {{m}} feature, is insensitive to the spectral shape and intensity of the exciting starlight. We derive a straightforward relation for determining the aliphatic fraction of the UIE carriers (i.e., the ratio of the number of C atoms in aliphatic units {N}{{C},{ali}} to that in aromatic rings {N}{{C},{aro}}) from the observed band ratios {({I}3.4/{I}3.3)}{obs}: {N

  3. Thermophysical and Rheological Properties of Imidazolium-Based Ionic Liquids: The Effect of Aliphatic versus Aromatic Functionality

    NASA Astrophysics Data System (ADS)

    Tao, Ran; Xue, Lianjie; Tamas, George; Quitevis, Edward; Simon, Sindee

    2014-03-01

    As a material class, ionic liquids possess attractive properties and have a wide range of potential uses. In this work, a series of imidazolium-based ionic liquids with the same carbon number varying from aliphatic to aromatic functionalities are investigated. The effects of cation symmetry and larger aromatic polycyclic functionality are studied. The thermal properties, including the glass transition temperature, melting temperature, and decomposition temperature, are characterized, and the density and the ionic conductivity are measured as a function of temperature. Rheological studies are performed using both steady-state and dynamic shear modes. The Cox-Merz relationship between the steady shear viscosity and the dynamic viscosity is examined. The temperature dependence of viscosity is described by the Vogel-Fulcher-Tammann equation and the dynamic fragility is calculated for each ionic liquid and compared to the fragility obtained from calorimetry. Master curves of dynamic shear responses are also constructed and will be discussed.

  4. A novel chiral aliphatic-aromatic diamine promoted direct, highly enantio- and diastereoselective Michael addition of cyclohexanone to nitroolefins under solvent-free conditions.

    PubMed

    Miao, Shifeng; Bai, Jinjin; Yang, Jin; Zhang, Yawen

    2010-10-01

    A series of new highly efficient chiral aliphatic-aromatic diamine catalysts have been designed and successfully applied to the asymmetric Michael addition of cyclohexanone with nitroolefins under solvent-free conditions without any acidic additives. The desired adducts were obtained in high yields with excellent enantio- and diastereoselectivities of syn products (up to >99% ee, >99:1 dr).

  5. Sources, distribution, and water column processes of aliphatic and polycyclic aromatic hydrocarbons in the northwestern Black Sea water

    SciTech Connect

    Maldonado, C.; Bayona, J.M.; Bodineau, L.

    1999-08-15

    Aliphatic and aromatic hydrocarbons have been determined in suspended particulate matter collected at subsurficial seawater and three vertical profiles in a transect from the continental shelf, slope, and deep basin of the western Black Sea. The dissolved phase was collected at subsurficial and in the redoxcline. The highest concentrations of hydrocarbons were detected in the Danube, Dnieper, and Dniester River Estuaries and other point sources of pollution located offshore Romania and Bulgaria where oil production and refining is carried out. Concentrations of hydrocarbons decreased with increasing distance from the coast, but relatively high concentrations were found at the open stations where the particulate organic carbon (POC) is higher. Fossil PAHs are predominant in the coastal stations, and the unresolved complex mixture (UCM) of aliphatic hydrocarbons is predominantly of a fossil common origin according to the hopane and sterane distribution. The fossil to pyrolytic PAH ratio decreases with source distance attributable to a deposition of pyrolytic PAHs. The spatial distribution of PAHs found in the dissolved phase is evenly distributed. The unresolved complex mixture/alkane ratio is higher in the dissolved phase and can be attributable to a faster degradation of labile n-alkanes in this phase. Vertical profiles of hydrocarbons in suspended particles show two submaxima located in the biomass maximum abundance and at the redoxcline where there is an enrichment referred to POC due to phytoplankton or bacteria uptake, respectively.

  6. Flux of aliphatic and polycyclic aromatic hydrocarbons to Central Puget Sound from Seattle (Westpoint) primary sewage effluent

    SciTech Connect

    Barrick, R.C.

    1982-10-01

    Concentrations and mass emission rates are reported for hydrocarbons in a 20-month evaluation of primary municipal waste water discharging to marine waters of Puget Sound from Seattle, WA. On the average, METRO (Westpoint) discharges 475 metric tons/year of aliphatic hydrocarbons and approximately 1 metric ton/year of 3-7 ring polynuclear aromatic hydrocarbons (PAH), corresponding to discharges of 2.6 and 0.005 g/(capita day), respectively. Effluent PAH containing greater than or equal to 4 rings apparently derive principally from storm-water contributions. A comparison of METRO's yearly average discharge of different hydrocarbon components with observed hydrocarbon fluxes in adjacent Puget Sound surface sediments suggests negligible accumulations of the resolvable alkanes (derived from the effluent), partial accumulations of an unresolved complex mixture and phenanthrene, and substantial accumulations of the greater than or equal to4-ring PAH. The discharge accounts for a major portion of the sedimentary aliphatic fossil hydrocarbon flux and is one of several important PAH contributors. 45 references, 2 figures, 5 tables.

  7. Simultaneous determination of aliphatic and aromatic amines in ambient air and airborne particulate matters by gas chromatography-mass spectrometry

    NASA Astrophysics Data System (ADS)

    Akyüz, Mehmet

    2008-05-01

    A gas chromatography-mass spectrometry (GC-MS) method has been proposed for the simultaneous determination of aliphatic and aromatic amines in ambient air and airborne particulate matters (PMs). The method includes collection of the particulate matters (PM2.5 and PM10) using dichotomous Partisol 2025 sampler followed by extraction of the compounds into acidic solution, and pre-concentration of the compounds by percolating the air samples through the acidic solution, then ion-pair extraction of amines with bis-2-ethylhexylphosphate and derivatisation with isobutyl chloroformate prior to their GC-MS analysis in both electron impact and positive and negative ion chemical ionisation mode as their isobutyloxycarbonyl (isoBOC) derivatives. In the present study, ambient air and airborne particulate samples collected in Zonguldak province during summer and winter times of 2006-2007 were analysed for aliphatic and aromatic amines by the proposed method and the method was shown to be suitable for the simultaneous determination of these compounds at the levels of pg m-3 in air and airborne particulate samples. The seasonal distributions of bioactive amines in concentrations in ambient air and airborne PMs were evaluated as they are significant for the estimation of their effects on the environment and human health. The concentration levels of water soluble amines fluctuate significantly within a year with higher means and peak concentrations, probably due to the increased emissions from coal-fired domestic and central heating, in the winter times compared to the summer times. The results indicated that the relative amine content in particulates modulates with molecular mass and time of the year and the relative amine content especially in fine fractions of inhalable airborne particulates increases with the molecular mass of species but decreases with temperature.

  8. Transition metal-free intramolecular regioselective couplings of aliphatic and aromatic C-H bonds.

    PubMed

    Tian, Hua; Yang, Haijun; Zhu, Changjin; Fu, Hua

    2016-01-29

    Cross-dehydrogenative couplings of two different C-H bonds have emerged as an attractive goal in organic synthesis. However, achieving regioselective C-H activation is a great challenge because C-H bonds are ubiquitous in organic compounds. Actually, the regioselective couplings promoted by enzymes are a common occurrence in nature. Herein, we have developed simple, efficient and general transition metal-free intramolecular couplings of alphatic and aromatic C-H bonds. The protocol uses readily available aryl triazene as the radical initiator, cheap K2S2O8 as the oxidant, and the couplings were performed well with excellent tolerance of functional groups. Interestingly, α-carbon configuration of some amino acid residues in the substrates was kept after the reactions, and the couplings for substrates with substituted phenylalanine residues exhibited complete β-carbon diastereoselectivity for induction of the chiral α-carbon. Therefore, the present study should provide a novel strategy for regioselective cross-dehydrogenative couplings of two different C-H bonds.

  9. Aliphatic and aromatic plant biopolymer dynamics in soil particles isolated from sequential density fractionation

    NASA Astrophysics Data System (ADS)

    Caldwell, B.; Filley, T.; Sollins, P.; Lajtha, K.; Swanston, C.; Kleber, M.; Kramer, M.

    2007-12-01

    A recent multi-layer-based soil organic matter-mineral interaction mechanistic model to describe the nature of soil organic matter-mineral surface mechanism for soil organic matter stabilization predicts that proteinaceous and aliphatic materials establish the core of strong binding-interactions upon which other organic matter is layered. A key methodology providing data underpinning this hypothesis is sequential density fractionation where soil is partitioned into particles of increasing density with the assumption that a partial control on organic matter distribution through density series is the thickness of its layering. Four soils of varying mineralogy and texture were investigated for their biopolymer, isotopic, and mineralogical properties. Light fractions (<1.8 g/cm3), although dominanted by organic detritus, did not always contain the highest concentration of lignin and substituted fatty acids from cutin and suberin while heavier fractions, 1.8-2.6 g/cm3, exhibited a progressive decrease in concentration in plant derived biopolymers with density. Extractable lignin phenols exhibited a progressive oxidation state with density. The concentration of biopolymers roughly mirrored the C:N ratio of soil particles which dropped consistently with increasing particle density. Although, in all soils, both lignin phenols and SFA concentration generally decreased with increasing density the ratio SFA/lignin varied with density and depending upon the soil. All soils, except the oxisol, exhibited an increase in SFA with respect to lignin suggesting a selective stabilization of those material with respect to lignin. In the oxisol, which showed little variation in its hematite dominated mineralogy across density, SFA/lignin remained constant, potentially indicating a greater capacity to stabilize lignin in that system. Interestingly, the lignin oxidation state increased with density in the oxisol. Given the variation in soil character, the consistency in these trends it

  10. Carbon-rich dust past the asymptotic giant branch: Aliphatics, aromatics, and fullerenes in the Magellanic Clouds

    SciTech Connect

    Sloan, G. C.; Lagadec, E.; Zijlstra, A. A.; Kraemer, K. E.; Weis, A. P.; Matsuura, M.; Volk, K.; Peeters, E.; Cami, J.; Duley, W. W.; Bernard-Salas, J.; Kemper, F.

    2014-08-10

    Infrared spectra of carbon-rich objects that have evolved off the asymptotic giant branch reveal a range of dust properties, including fullerenes, polycyclic aromatic hydrocarbons (PAHs), aliphatic hydrocarbons, and several unidentified features, including the 21 μm emission feature. To test for the presence of fullerenes, we used the position and width of the feature at 18.7-18.9 μm and examined other features at 17.4 and 6-9 μm. This method adds three new fullerene sources to the known sample, but it also calls into question three previous identifications. We confirm that the strong 11 μm features seen in some sources arise primarily from SiC, which may exist as a coating around carbonaceous cores and result from photo-processing. Spectra showing the 21 μm feature usually show the newly defined Class D PAH profile at 7-9 μm. These spectra exhibit unusual PAH profiles at 11-14 μm, with weak contributions at 12.7 μm, which we define as Class D1, or show features shifted to ∼11.4, 12.4, and 13.2 μm, which we define as Class D2. Alkyne hydrocarbons match the 15.8 μm feature associated with 21 μm emission. Sources showing fullerene emission but no PAHs have blue colors in the optical, suggesting a clear line of sight to the central source. Spectra with 21 μm features and Class D2 PAH emission also show photometric evidence for a relatively clear line of sight to the central source. The multiple associations of the 21 μm feature with aliphatic hydrocarbons suggest that the carrier is related to this material in some way.

  11. The C-H Stretching Features at 3.2--3.5 μm of Polycyclic Aromatic Hydrocarbons with Aliphatic Sidegroups

    NASA Astrophysics Data System (ADS)

    Yang, X. J.; Li, Aigen; Glaser, R.; Zhong, J. X.

    2016-07-01

    The so-called “unidentified” infrared emission (UIE) features at 3.3, 6.2, 7.7, 8.6, and 11.3 μm are ubiquitously seen in a wide variety of astrophysical regions. The UIE features are characteristic of the stretching and bending vibrations of aromatic hydrocarbon materials, e.g., polycyclic aromatic hydrocarbon (PAH) molecules. The 3.3 μm aromatic C-H stretching feature is often accompanied by a weaker feature at 3.4 μm. The latter is generally thought to result from the C-H stretch of aliphatic groups attached to the aromatic systems. The ratio of the observed intensity of the 3.3 μm aromatic C-H feature to that of the 3.4 μm aliphatic C-H feature allows one to estimate the aliphatic fraction of the UIE carriers, provided that the intrinsic oscillator strengths of the 3.3 μm aromatic C-H stretch ({A}3.3) and the 3.4 μm aliphatic C-H stretch ({A}3.4) are known. While previous studies on the aliphatic fraction of the UIE carriers were mostly based on the {A}3.4/{A}3.3 ratios derived from the mono-methyl derivatives of small PAH molecules, in this work we employ density functional theory to compute the infrared vibrational spectra of PAH molecules with a wide range of sidegroups including ethyl, propyl, butyl, and several unsaturated alkyl chains, as well as all the isomers of dimethyl-substituted pyrene. We find that, except for PAHs with unsaturated alkyl chains, the corresponding {A}3.4/{A}3.3 ratios are close to that of mono-methyl PAHs. This confirms the predominantly aromatic nature of the UIE carriers previously inferred from the {A}3.4/{A}3.3 ratio derived from mono-methyl PAHs.

  12. Adsorption of aliphatic, alicyclic, and aromatic hydrocarbons on poly(ethylvinylbenzene-divinylbenzene) adsorbent at from effective zero to finite adsorbate surface coverage

    SciTech Connect

    Djordjevic, N.M.; Laub, R.J.; Kopecni, M.M.; Milonjic, S.K.

    1986-06-01

    The solid/gas partition coefficients, K/sub s/, and related thermodynamic properties of a number of hydrocarbon adsorbates at effective zero surface coverage on commercial samples of the title adsorbent, Porapak Q, were measured over the temperature range 293-443 K. The enthalpies of adsorption derived from the averaged absolute K/sub s/ gave incremental ..delta..H/sub s//sup 0/ of -7.5 kJ mol/sup -1/ for aliphatic and alicyclic -CH/sub 2/-, as well as aromatic -CH=, and -12 kJ mol/sup -1/ for -CH/sub 3/, while the differential entropies calculated in terms of translational motions were found to predict correctly the trends observed in the experimental ..delta..S/sub s//sup 0/. The technique of elution by characteristic point (ECP) was then used to derive the finite concentration adsorption isotherms and isosteric heats of adsorption of n-hexane, n-heptane, cyclohexane, benzene, carbon tetrachloride, and acetone at fractional adsorbate pressures, p/p/sup 0/, of no greater than 10/sup -2/ on a particular sample of the title absorbent at 20/sup 0/ intervals over the temperature range 413-493 K.

  13. Substrate specificities of cutinases on aliphatic-aromatic polyesters and on their model substrates.

    PubMed

    Perz, Veronika; Bleymaier, Klaus; Sinkel, Carsten; Kueper, Ulf; Bonnekessel, Melanie; Ribitsch, Doris; Guebitz, Georg M

    2016-03-25

    The enzymatic hydrolysis of the biodegradable polyester ecoflex and of a variety of oligomeric and polymeric ecoflex model substrates was investigated. For this purpose, substrate specificities of two enzymes of typical compost inhabitants, namely a fungal cutinase from Humicola insolens (HiC) and a bacterial cutinase from Thermobifida cellulosilytica (Thc_Cut1) were compared. Model substrates were systematically designed with variations of the chain length of the alcohol and the acid as well as with varying content of the aromatic constituent terephthalic acid (Ta). HPLC/MS identification and quantification of the hydrolysis products terephthalic acid (Ta), benzoic acid (Ba), adipic acid (Ada), mono(4-hydroxybutyl) terephthalate (BTa), mono-(2-hydroxyethyl) terephthalate (ETa), mono-(6-hydroxyhexyl) terephthalate (HTa) and bis(4-hydroxybutyl) terephthalate (BTaB) indicated that these enzymes indeed hydrolyze the tested esters. Shorter terminal chain length acids but longer chain length alcohols in oligomeric model substrates were generally hydrolyzed more efficiently. Thc_Cut1 hydrolyzed aromatic ester bonds more efficiently than HiC resulting in up to 3-fold higher concentrations of the monomeric hydrolysis product Ta. Nevertheless, HiC exhibited a higher overall hydrolytic activity on the tested polyesters, resulting in 2-fold higher concentration of released molecules. Thermogravimetry and differential scanning calorimetry (TG-DSC) of the polymeric model substrates revealed a general trend that a lower difference between melting temperature (Tm) and the temperature at which the enzymatic degradation takes place resulted in higher susceptibility to enzymatic hydrolysis.

  14. Purification of Pseudomonas putida acyl coenzyme A ligase active with a range of aliphatic and aromatic substrates.

    PubMed Central

    Fernández-Valverde, M; Reglero, A; Martinez-Blanco, H; Luengo, J M

    1993-01-01

    Acyl coenzyme A (acyl-CoA) ligase (acyl-CoA synthetase [ACoAS]) from Pseudomonas putida U was purified to homogeneity (252-fold) after this bacterium was grown in a chemically defined medium containing octanoic acid as the sole carbon source. The enzyme, which has a mass of 67 kDa, showed maximal activity at 40 degrees C in 10 mM K2PO4H-NaPO4H2 buffer (pH 7.0) containing 20% (wt/vol) glycerol. Under these conditions, ACoAS showed hyperbolic behavior against acetate, CoA, and ATP; the Kms calculated for these substrates were 4.0, 0.7, and 5.2 mM, respectively. Acyl-CoA ligase recognizes several aliphatic molecules (acetic, propionic, butyric, valeric, hexanoic, heptanoic, and octanoic acids) as substrates, as well as some aromatic compounds (phenylacetic and phenoxyacetic acids). The broad substrate specificity of ACoAS from P. putida was confirmed by coupling it with acyl-CoA:6-aminopenicillanic acid acyltransferase from Penicillium chrysogenum to study the formation of several penicillins. Images PMID:8476289

  15. Presence of aliphatic and polycyclic aromatic hydrocarbons in near-surface sediments of an oil spill area in Bohai Sea.

    PubMed

    Li, Shuanglin; Zhang, Shengyin; Dong, Heping; Zhao, Qingfang; Cao, Chunhui

    2015-11-15

    In order to determine the source of organic matter and the fingerprint of the oil components, 50 samples collected from the near-surface sediments of the oil spill area in Bohai Sea, China, were analyzed for grain size, total organic carbon, aliphatic hydrocarbons (AHs), and polycyclic aromatic hydrocarbons (PAHs). The concentrations of C15-35 n-alkanes and 16 United States Environmental Protection Agency (US EPA) priority pollutant PAHs were found in the ranges of 0.88-3.48μg g(-1) and 9.97-490.13ng/g, respectively. The terrestrial organic matters characterized by C27-C35 n-alkanes and PAHs, resulting from the combustion of higher plants, are dominantly contributed from the transportation of these plants by rivers. Marine organic matters produced from plankton and aquatic plants were represented by C17-C26 n-alkanes in AHs. Crude oil, characterized by C17-C21 n-alkanes, unresolved complex mixture (UCM) with a mean response factor of C19 n-alkanes, low levels of perylene, and a high InP/(InP+BghiP) ratio, seeped into the oceans from deep hydrocarbon reservoirs, as a result of geological faults.

  16. Chemical and morphological characterization of soot and soot precursors generated in an inverse diffusion flame with aromatic and aliphatic fuels

    SciTech Connect

    Santamaria, Alexander; Mondragon, Fanor; Yang, Nancy; Eddings, Eric

    2010-01-15

    Knowledge of the chemical and physical structure of young soot and its precursors is very useful in understanding the paths leading to soot particle inception. This paper presents chemical and morphological characterization of the products generated in ethylene and benzene inverse diffusion flames (IDF) using different analytical techniques. The trend in the data indicates that the soot precursor material and soot particles generated in the benzene IDF have a higher degree of complexity than the samples obtained in the ethylene IDF, which is reflected by an increase in the aromaticity of the chloroform extracts observed by {sup 1}H NMR and FT-IR, and shape and size of soot particles obtained by TEM and HR-TEM. It is important to highlight that the soot precursor material obtained at the lower positions in the ethylene IDF has a significant contribution of aliphatic groups, which play an important role in the particle inception and mass growth processes during the early stages of soot formation. However, these groups progressively disappear in the samples taken at higher positions in the flame, due to thermal decomposition processes. (author)

  17. Distribution and fate of aliphatic and aromatic hydrocarbons in Antarctic fauna and environment

    NASA Astrophysics Data System (ADS)

    Platt, H. M.; Mackie, P. R.

    1980-03-01

    With the depletion of oil resources in more accessible areas, those of remote regions are being considered or indeed are now being exploited. In many of these regions, especially the polar ones, little is known of the effects such exploitation will have on the environment. But it is known that the ecosystems are often subject to great stress by natural climatic conditions and additional burdens imposed by man may have catastrophic environmental effects. South Georgia, a sub-Antarctic island, has a history of industrial activity mainly concerned with whaling operations that peaked around 1925-1935 but has since declined to virtually nothing. Studies of the ecology of the area provided a unique opportunity to assess the long-term effects that such activities had on the ecosystem. Off the whaling stations a considerable amount of waste material, including fuel oil, was released into the bays and inevitably some of this material was deposited in the sediments. Chemical evidence in the form of both paraffinic and aromatic hydrocarbons still persists in the sediments. The implications of this persistence in relation to the possible influence of the low temperature conditions are discussed. The superficial sediments, marine biota and terrestrial plants, which since 1965 have returned virtually to a pristine state, contain hydrocarbons essentially similar to unpolluted areas around the coast of Britain. Relatively high levels of carcinogenic/mutagenic polynuclear aromatic hydrocarbons in surface sediments suggests a world-wide background of abiogenic hydrocarbons probably disseminated by airborne transport. This appears to indicate that contamination reaches even remote parts of the world in relatively undiminished quantities.

  18. 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.

  19. [Mutagenicity of mixtures of halogenated aliphatic hydrocarbons and polycyclic aromatic hydrocarbons in the Ames test with TA98 and TA100].

    PubMed

    Kevekordes, S; Porzig, J; Gebel, T; Dunkelberg, H

    1998-02-01

    Within the framework of the assessment of the genotoxic potential of environment samples the Salmonella-microsome-test (Ames-test) is often used as a screening-test. It is one of the most applied biotest systems and possesses a large scientific acceptance. Because most environment samples are mixtures of various substances, possible effects resulting from the combination should be taken into account with regard to the mutagenic potential. In this context we investigated eight polycyclic aromatic hydrocarbons each combined with six halogenated aliphatic hydrocarbons as to their mutagenicity in the Salmonella-microsome-test with TA98 and TA100. For an exogenous metabolizing system, Arochlor 1254 induced rat liver S9-mix was used. Benz-a-pyrene in combination with bromodichloromethane (Ames neg. in TA98 and TA100 +S9) showed an increase in the number of the revertants up to 25% in TA98 and TA100 (+S9). Carbon tetrachloride (Ames neg. in TA98 and TA100 +S9) showed in TA100 (+S9) an increase in the number of the revertants of 18% at most. In the combination 3-methylcholanthrene with dichloromethane the number of revertants in TA98 (+S9) increased by 25% and in TA100 (+S9) by 18%. Hexachloroethane (weakly mutagenic in TA98 +S9) in combination showed in TA98 (+S9) a slightly increased number of revertants with benz-a-pyrene as well with 3-methylcholanthrene. All the other substances tested (chrysene, phenanthrene, anthanthrene, dibenz-a, i-pyrene, triphenylene, fluoranthene) in combination with either tetrachloroethylene or trichloroethene did not cause an increase in mutagenicity.

  20. Patterns and sources of particle-phase aliphatic and polycyclic aromatic hydrocarbons in urban and rural sites of western Greece

    NASA Astrophysics Data System (ADS)

    Kalaitzoglou, Maria; Terzi, Eleni; Samara, Constantini

    Particle-bound aliphatic and polycyclic aromatic hydrocarbons (AHs and PAHs, respectively) were determined in the ambient air of the Eordea basin, in western Greece, where intensive coal burning for power generation takes place. Thirteen PAHs, n-alkanes (C 14-C 35), hopanes, and isoprenoid hydrocarbons (pristane and phytane) were determined in the total suspended particles collected from the atmosphere of four sites within the basin receiving potential impacts from various sources, such as fly ash, coal mining, automobile traffic, domestic heating, and agricultural or refuse burning. The same organic species were also determined in the fly ash generated in power stations, and in particulate emissions from open burning of biomass (dry corn leaves) and refuse burning. Organic particle sources were resolved using concentration diagnostic ratios and factor analysis (FA). A multivariate statistical receptor model (Absolute Principal Component Analysis, APCA) was finally employed to estimate the contribution of identified sources to the measured concentrations of organic pollutants. Four major sources for ambient PAHs and AHs were identified displaying variable contribution in different sites: (a) fossil fuel combustion, (b) biogenic emissions, (c) refuse burning, and (d) oil residues. Fuel combustion was the major source of ambient PAHs and an important source of n-alkanes in the range C 21-C 28. Oil residues were found to be the major source of low molecular weight n-alkanes (particularly the C 14-C 16), and an important source of pristane, phytane and UCM. Biogenic sources were primarily responsible for the high molecular weight n-alkanes explaining almost the entire concentration levels of homologues >C 32. Biomass burning was particularly important for the C 23-C 26n-alkanes. Despite the vicinity of certain sampling sites to power stations, coal fly ash was not identifiable as a source for ambient PAHs and AHs.

  1. Size exclusion chromatography for the unambiguous detection of aliphatics in fractions from petroleum vacuum residues, coal liquids, and standard materials, in the presence of aromatics

    SciTech Connect

    Eiman M. Al-Muhareb; Fatma Karaca; Trevor J. Morgan; Alan A. Herod; Ian D. Bull; Rafael Kandiyoti

    2006-05-15

    A method has been developed using size exclusion chromatography (SEC) in heptane eluent that can detect aliphatics unambiguously without fractionation to remove aromatics. Spherical molecules such as colloidal silicas elute at the exclusion limit, while alkanes up to C{sub 50} elute through the porosity of the column. Detection of aliphatics was defined by use of an evaporative light scattering (ELS) detector with the simultaneous absence of UV absorbance at 300 nm. Alkanes smaller than C{sub 12} were not detected because the conditions of operation of the ELS caused their evaporation. All aromatics eluted after the permeation limit of about 25 min and were not detected until well after 45 min by their UV absorbance. The SEC method was applied to petroleum vacuum residues and coal liquids, and their fractions were soluble in pentane or heptane. High-temperature (HT) GC-MS confirmed the presence of alkanes in the pentane- and heptane-soluble fractions of petroleum vacuum residues, but did not elute any of the aromatics known to be present from SEC. Alkanes were examined in pentane-soluble fractions of a coal digest and a low-temperature coal tar; alkanes up to C{sub 40} were detected in the low-temperature tar and, although present in the digest, were masked by aromatics. No alkanes were detected by either SEC or HT GC-MS in fractions from a coal tar pitch. Aromatics in coal liquids and one petroleum residue were also examined by SEC using NMP as eluent and by UV fluorescence spectroscopy. The SEC method will find application to pentane- and heptane-soluble fractions of petroleum liquids and coal liquids where the alkanes are concentrated relative to the more abundant aromatics. 43 refs., 10 figs., 2 tabs.

  2. Mixed aliphatic and aromatic composition of evaporating very small grains in NGC 7023 revealed by the 3.4/3.3 μm ratio

    NASA Astrophysics Data System (ADS)

    Pilleri, P.; Joblin, C.; Boulanger, F.; Onaka, T.

    2015-05-01

    Context. A chemical scenario was proposed for photon-dominated regions (PDRs) according to which UV photons from nearby stars lead to the evaporation of very small grains (VSGs) and the production of gas-phase polycyclic aromatic hydrocarbons (PAHs). Aims: Our goal is to achieve better insight into the composition and evolution of evaporating very small grains (eVSGs) and PAHs through analyzing the infrared (IR) aliphatic and aromatic emission bands. Methods: We combined spectro-imagery in the near- and mid-IR to study the spatial evolution of the emission bands in the prototypical PDR NGC 7023. We used near-IR spectra obtained with the IRC instrument onboard AKARI to trace the evolution of the 3.3 μm and 3.4 μm bands, which are associated with aromatic and aliphatic C-H bonds on PAHs. The spectral fitting involved an additional broad feature centered at 3.45 μm that is often referred to as the plateau. Mid-IR observations obtained with the IRS instrument onboard the Spitzer Space Telescope were used to distinguish the signatures of eVSGs and neutral and cationic PAHs. We correlated the spatial evolution of all these bands with the intensity of the UV field given in units of the Habing field G0 to explore how their carriers are processed. Results: The intensity of the 3.45 μm plateau shows an excellent correlation with that of the 3.3 μm aromatic band (correlation coefficient R = 0.95) and a relatively poor correlation with the aliphatic 3.4 μm band (R = 0.77). This indicates that the 3.45 μm feature is dominated by the emission from aromatic bonds. We show that the ratio of the 3.4 μm and 3.3 μm band intensity (I3.4/I3.3) decreases by a factor of 4 at the PDR interface from the more UV-shielded layers (G0 ~ 150,I3.4/I3.3 = 0.13) to the more exposed layers (G0> 1 × 104,I3.4/I3.3 = 0.03). The intensity of the 3.3 μm band relative to the total neutral PAH intensity shows an overall increase with G0, associated with an increase of both the hardness of the

  3. Mixed aliphatic and aromatic composition of evaporating very small grains in NGC 7023 revealed by the 3.4/3.3 μm ratio

    PubMed Central

    Pilleri, P.; Joblin, C.; Boulanger, F.; Onaka, T.

    2015-01-01

    Context A chemical scenario was proposed for photon-dominated regions (PDRs) according to which UV photons from nearby stars lead to the evaporation of very small grains (VSGs) and the production of gas-phase polycyclic aromatic hydrocarbons (PAHs). Aims Our goal is to achieve better insight into the composition and evolution of evaporating very small grains (eVSGs) and PAHs through analyzing the infrared (IR) aliphatic and aromatic emission bands. Methods We combined spectro-imagery in the near- and mid-IR to study the spatial evolution of the emission bands in the prototypical PDR NGC 7023. We used near-IR spectra obtained with the IRC instrument onboard AKARI to trace the evolution of the 3.3 μm and 3.4 μm bands, which are associated with aromatic and aliphatic C–H bonds on PAHs. The spectral fitting involved an additional broad feature centered at 3.45 μm that is often referred to as the plateau. Mid-IR observations obtained with the IRS instrument onboard the Spitzer Space Telescope were used to distinguish the signatures of eVSGs and neutral and cationic PAHs. We correlated the spatial evolution of all these bands with the intensity of the UV field given in units of the Habing field G0 to explore how their carriers are processed. Results The intensity of the 3.45 μm plateau shows an excellent correlation with that of the 3.3 μm aromatic band (correlation coefficient R = 0.95) and a relatively poor correlation with the aliphatic 3.4 μm band (R=0.77). This indicates that the 3.45 μm feature is dominated by the emission from aromatic bonds. We show that the ratio of the 3.4 μm and 3.3 μm band intensity (I3.4/I3.3) decreases by a factor of 4 at the PDR interface from the more UV-shielded layers (G0 ~ 150, I3.4/I3.3 = 0.13) to the more exposed layers (G0 > 1 × 104, I3.4/I3.3 = 0.03). The intensity of the 3.3 μm band relative to the total neutral PAH intensity shows an overall increase with G0, associated with an increase of both the hardness of the UV

  4. Limiting activity coefficients of some aromatic and aliphatic nitro compounds in water

    SciTech Connect

    Benes, M.; Dohnal, V.

    1999-09-01

    Limiting activity coefficients of nine nitroaromatic compounds and four nitroalkanes in water were determined in the range of environmentally related temperatures by measuring suitable phase equilibria. For liquid and solid nitroaromatics (nitrobenzene, 2-nitrotoluene, 3-nitrotoluene, 4-nitrotoluene, 2-nitrophenol, 3-nitrophenol, 4-nitrophenol, 1-chloro-2-nitrobenzene, and 1-chloro-4-nitrobenzene) the aqueous solubilities were measured by a conventional batch contacting method with UV spectrophotometric analysis, while for nitroalkanes (nitromethane, nitroethane, 1-nitropropane, and 2-nitropropane) the air-water partitioning (Henry`s law constant H{sub 12} or air-water partition coefficient K{sub aw}) was determined by the inert gas stripping method employing gas chromatography. Whenever possible, results were compared to literature values. Calculation of H{sub 12} or K{sub aw} for nitroaromatics from the measured solubilities is hindered by the lack of reliable vapor pressure data. On the basis of the temperature dependences of the solubilities measured, the enthalpies of solution at infinite dilution for the nitroaromatics in water were evaluated.

  5. Distribution of aliphatic hydrocarbons, polycyclic aromatic hydrocarbons and organochlorinated pollutants in deep-sea sediments of the Southern Cretan margin, Eastern Mediterranean Sea: a baseline assessment.

    PubMed

    Mandalakis, Manolis; Polymenakou, Paraskevi N; Tselepides, Anastasios; Lampadariou, Nikolaos

    2014-07-01

    Deep sediments from the southern Cretan margin were analyzed to establish baseline levels for various types of organic pollutants before the anticipated intensification of anthropogenic activities. The total concentration of aliphatic hydrocarbons (ΣAH:326-3758ngg(-1), dry weight) was similar to those reported for deep sediments of the western Mediterranean Sea, while considerably lower levels were measured for polycyclic aromatic hydrocarbons (ΣPAH:9-60ngg(-1)). Source-diagnostic ratios suggested that the aliphatic hydrocarbons in sediments were mainly of terrestrial biogenic origin, while polycyclic aromatic hydrocarbons stemmed from the deposition of long-range transported combustion aerosols. Among the organochlorinated compounds analyzed, β-hexachlorocyclohexane (β-HCH:222-7052pgg(-1)), 1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane (p,p'-DDT:37-2236pgg(-1)) and polychlorinated biphenyls (ΣPCB:38-1182pgg(-1)) showed the highest abundance in sediments. The presence of HCHs and PCBs was attributed to historical inputs that have undergone extensive weathering, whereas an ongoing fresh input was suggested for p,p'-DDT. Multiple linear regression analysis revealed that the levels of the various pollutants in sediments were controlled by different factors, but with organic carbon content playing a prominent role in most cases.

  6. {Polycyclic aromatic hydrocarbons (PAHs) and aliphatic hydrocarbons in gas and particle phases in two sites of Mexico: MILAGRO project}

    NASA Astrophysics Data System (ADS)

    Amador-Muñoz, O.; Villalobos-Pietrini, R.; Castro, T.; Gaspariano-Larino, R.

    2009-04-01

    Aliphatic hydrocarbons are markers of anthropogenic and biogenic emission sources1; meanwhile PAHs are generated by incomplete combustion sources2. The last ones are important compounds due to their carcinogenic and mutagenic properties3,4. The aim of this study was to identify and quantify aliphatic hydrocarbons and PAHs in gas and particles phases of the atmospheric aerosol and to determine the day and night time behavior during the MILAGRO (Megacity Initiative: Local Global and Research Observations) campaign. The gas phase was collected on polyurethane foam, while particles less than 2.5 m (PM2.5) were collected on glass fiber filters covered with Teflon (TIGF, pallflex) of 8x10 in. Samplings were carried out with a high volume sampler (Tisch) with a flow of 1.13 m3 min-1 at two sites: Instituto Mexicano del Petróleo (T0) and Tecamac (T1) located at North and Northeast of Mexico City, respectively during day (7:00 am-7:00 pm) and night time (7:00 pm-7:00 am) from 1 to 29 of March, 2006. Ninteen PAHs and 23 aliphatic hydrocarbons from n-C13H28 to n-C35H72 were analyzed by gas chromatography coupled to mass spectrometry in impact mode. The samples were spiked with deuterads PAHs and aliphatics hydrocarbons before ultrasound extraction. Medians comparisons were made with Mann-Whitney U test. PAHs with molecular weight (MW) less than 228 g mol-1 were distributed in the gas phase, in both sites. Higher concentrations of PAHs ≥ 228 g mol-1 in PM2.5, were observed during night period (p

  7. Aliphatic and polycyclic aromatic hydrocarbons (PAHs) in soils of the northwest Qinling Mountains: Patterns, potential risk and an appraisal of the PAH ratios to infer their source.

    PubMed

    Liu, Yanhong; Wu, Yingqin; Xia, Yanqing; Lei, Tianzhu; Tian, Chuntao; Hou, Xiaohuan

    2017-03-21

    Surface soils from the tourist areas of the northwest Qinling Mountains were analyzed to determine the concentrations, probable sources and potential risks of hydrocarbons. Concentrations of aliphatic and aromatic hydrocarbons ranged from 4.18 to 3240 ng g(-1) and 0.0462 to 101 ng g(-1) dry weight, respectively. The extent of soil contamination by hydrocarbons was generally typified by unpolluted to slightly polluted levels. The incremental lifetime cancer risks (ILCRs) for exposure to soil-borne PAHs indicated complete safety for tourists. Early diagenesis of natural products, bacteria activities and petroleum were the three main sources of aliphatic hydrocarbons, while the transport of air pollutants from pyrolytic processes was the main origin of PAHs. Because the photochemical reaction of PAHs in the atmosphere would produce lower ratios for Ant/(Ant + Phe), BaA/(BaA + Chr) and IcdP/(IcdP + BghiP), but a higher ratio for Fla/(Fla + Pyr), the source classification highly depended on the diagnostic ratios chosen. The plot of ΣCOM/Σ13PAH vs. ΣLMW/ΣHMWPAH provide additional information to distinguish the origins of PAHs, and it showed a cluster of pyrogenic sources except for sample JFS-8. Four sources were resolved by principal component analysis: (1) a low temperature pyrogenic process related to the use of fossil fuel and biomass, such as charcoal, straw and wood, which contributes 63.1% of the measured PAHs; (2) the potential contribution of diagenetic processes, contributing 18.4%; (3) traffic emissions, contributing 9.27%; and (4) bioconversion/bacterial action, contributing 5.82%. Additionally, there was a good exponential relationship (r(2) = 0.969) between the natural n-alkanes ratio (NAR) and carbon preference index for C23-C35 (CPI23-35) for all samples, which is of great use for the determination of the origins of aliphatic hydrocarbon.

  8. Micellar control over tautomerization and photo-induced electron transfer of Lumichrome in the presence of aliphatic and aromatic amines: a transient absorption study

    NASA Astrophysics Data System (ADS)

    Sengupta, Chaitrali; Sarangi, Manas Kumar; Sau, Abhishek; Basu, Samita

    2017-03-01

    Lumichrome (Lc), a molecule consisting of a trinuclear alloxazine moiety is our present subject of interest. This molecule is subjected to tautomerization in the presence of pyridine, acetic acid, etc, through the formation of an eight-membered ring. In our present contribution, we have attempted to analyze the influence of the presence of an aliphatic amine, triethylamine (TEA) and an aromatic amine, N,N-dimethylaniline (DMA) in the double proton transfer step of the tautomerization as well as the photo-induced electron transfer (PET) from those amines to Lc. We have studied these phenomena within micelles, anionic and neutral, to observe the effect of confinement. Through our experiments, it could be stated that along with tautomerization and proton transfer, there is also evidence of PET in triplet excited state.

  9. Biodegradation of the (aliphatic + aromatic) fraction of Oural crude oil. Biomarker identification using GC/MS SIM and GC/MS/MS.

    PubMed

    Jacquot, F; Doumenq, P; Guiliano, M; Munoz, D; Guichard, J R; Mille, G

    1996-03-01

    A simplified fraction of the Oural crude oil (aliphatic and aromatic hydrocarbons) was incubated in the presence of an hydrocarbonoclastic bacterial community isolated from a marine sediment highly contaminated by petroleum residue. The biodegradation has been carried out under aerobic conditions for 5 weeks and followed by FTIR, UV synchronous luminescence and GC/FID. Disappearance of the n-alkanes (2nd week), an important attack of the isoprenoïd compounds (5th week) and preferential alteration of monomethylated polyaromatics were observed. Concerning the biomarkers, the bicyclic alkanes and pentacyclic terpanes have been comparatively elucidated using GC/MS data. The identification of C(26) to C(29) steranes has required a most selective method, namely GC/MS/MS. Many molecular ratios based on GC/MS abundances were calculated, which showed good stability. Consequently, they can be used to determine the origin of a petroleum even one altered by biodegradation.

  10. Isolation and characterization of a Mycobacterium species capable of degrading three- and four-ring aromatic and aliphatic hydrocarbons

    SciTech Connect

    Churchill, S.A.; Harper, J.P.; Churchill, P.F.

    1999-02-01

    Mycobacterium sp. strain CH1 was isolated from polycyclic aromatic hydrocarbon (PAH)-contaminated freshwater sediments and identified by analysis of 16S rDNA sequences. Strain CH1 was capable of mineralizing three- and four-ring PAHs including phenanthrene, pyrene, and fluoranthene. In addition, strain CH1 could utilize phenanthrene or pyrene as a sole carbon and energy source. A lag phase of at least 3 days was observed during pyrene mineralization. This lag phase decreased to less than 1 day when strain CH1 was grown in the presence of phenanthrene or fluoranthene. Strain CH1 also was capable of using a wide range of alkanes as sole carbon and energy sources. No DNA hybridization was detected with the nahAc gene probe, indicating that enzymes involved in PAH metabolism are not related to the well-characterized naphthalene dioxygenase gene. DNA hybridization was not detected when the alkB gene from Pseudomonas oleovorans was used under high-stringency conditions. However, there was slight but detectable hybridization under low-stringency conditions. This suggests a distant relationship between genes involved in alkane oxidation.

  11. Polycyclic aromatic hydrocarbons, aliphatic hydrocarbons, trace elements and monooxygenase activity in birds nesting on the North Platte River, Casper, Wyoming, USA

    USGS Publications Warehouse

    Custer, T.W.; Custer, Christine M.; Dickerson, K.; Allen, K.; Melancon, M.J.; Schmidt, L.J.

    2001-01-01

    Tree swallow (Tachycineta bicolor) and house wren (Troglodytes aedon) eggs and chicks were collected near a refinery site on the North Platte River, Casper, Wyoming, USA and at a reference site 10 km upstream. Total polycylic aromatic hydrocarbon (PAH) concentrations in swallow and wren chicks were higher at the refinery site than at the reference site. Polycylic aromatic hydrocarbon concentrations in sediment and chick dietary samples were consistent with these findings. The general lack of methylated PAHs in sediment, diet, and bird carcasses suggested that the PAHs were derived from combustion and not from petroleum. The predominance of odd numbered aliphatic hydrocarbons and the low ratios (≤ 0.25) of pristane: n-C17 and phytane: n-C18 in chick and diet samples also suggested that swallow and wren chicks were not being chronically exposed to petroleum. Mean ethoxyresorufin-O-dealkylase and benzyloxyresorufin-O-dealkylase activities in tree swallow livers averaged nine times higher at the refinery site than at the reference site and were probably induced by exposure to PAHs. Trace element concentrations in eggs and livers of swallows and wrens were similar or greater at the reference site than at the refinery site. Selenium, strontium, and boron concentrations were elevated in eggs and livers of swallows and wrens at both the refinery and reference sites.

  12. Distribution of trace metals, aliphatic hydrocarbons and polycyclic aromatic hydrocarbons in sediment cores from the Sicily Channel and the gulf of Tunis (south-western Mediterranean Sea).

    PubMed

    Mzoughi, Nadia; Chouba, Lassaad

    2011-01-01

    Under the framework of the IAEA's Technical Co-operation project RAF7/004, international research cruises were carried out in 2004 to assess the distribution of radionuclides and micropollutants in the south-western Mediterranean Sea. Sediments samples had variable concentrations of total aliphatic hydrocarbons and polycyclic aromatic hydrocarbons ranging from 0.2 to 1.8 microg g(-1) and 26.9 to 364.4 ng g(-1), respectively, in the Sicily Channel and from 0.7 to 2.8 microg g(-1) and 14.7 to 618.1 ng g(-1), respectively, in the open sea of the Gulf of Tunis. Hydrocarbon concentrations changed with depth and were relatively high at 3 cm and 10 cm depths. The use of 'fingerprint' ratios of certain isomeric pairs of polycyclic aromatic hydrocarbons (PAH) and the proportion of 2-3 ring and 4-5 ring PAH concentrations showed that the main origins are characteristic of petroleum sources. The ranges of trace metal concentrations, expressed in microgg(-1), in the Sicily Channel and in the Gulf of Tunis, respectively, were: Hg 0.009-0.2 and 0.02-0.1; Pb 9.9-26.1 and 21.2-32.5; Cd 0.06-0.1 and 0.07-0.33; Fe 23.7-28.1 and 29.9-36.2p; Zn 83-99.5 and 83-104; Mn 309.2-752.5 and 651-814; Cu 17.1-18.5 and 33.5-51.3. Sediment metal abundances were in the order: Mn > Zn > Fe > Cu > Pb > Cd > Hg. The results showed significant differences (p < 0.001) for trace metal and hydrocarbon mean concentrations between the two cores. These concentrations are generally similar to the background levels from the Mediterranean Sea and could be affected by physico-chemical conditions and sedimentation rate as well as biodegradation.

  13. Enrichment of aliphatic, alicyclic and aromatic acids by oil-degrading bacteria isolated from the rhizosphere of plants growing in oil-contaminated soil from Kazakhstan.

    PubMed

    Mikolasch, Annett; Omirbekova, Anel; Schumann, Peter; Reinhard, Anne; Sheikhany, Halah; Berzhanova, Ramza; Mukasheva, Togzhan; Schauer, Frieder

    2015-05-01

    Three microbial strains were isolated from the rhizosphere of alfalfa (Medicago sativa), grass mixture (Festuca rubra, 75 %; Lolium perenne, 20 %; Poa pratensis, 10 %), and rape (Brassica napus) on the basis of their high capacity to use crude oil as the sole carbon and energy source. These isolates used an unusually wide spectrum of hydrocarbons as substrates (more than 80), including n-alkanes with chain lengths ranging from C12 to C32, monomethyl- and monoethyl-substituted alkanes (C12-C23), n-alkylcyclo alkanes with alkyl chain lengths from 4 to 18 carbon atoms, as well as substituted monoaromatic and diaromatic hydrocarbons. These three strains were identified as Gordonia rubripertincta and Rhodococcus sp. SBUG 1968. During their transformation of this wide range of hydrocarbon substrates, a very large number of aliphatic, alicyclic, and aromatic acids was detected, 44 of them were identified by GC/MS analyses, and 4 of them are described as metabolites for the first time. Inoculation of plant seeds with these highly potent bacteria had a beneficial effect on shoot and root development of plants which were grown on oil-contaminated sand.

  14. Isolation, characterization of Rhodococcus sp. P14 capable of degrading high-molecular-weight polycyclic aromatic hydrocarbons and aliphatic hydrocarbons.

    PubMed

    Song, Xiaohui; Xu, Yan; Li, Gangmin; Zhang, Ying; Huang, Tongwang; Hu, Zhong

    2011-10-01

    Rhodococcus sp. P14 was isolated from crude oil-contaminated sediments. This strain was capable of utilizing three to five rings polycyclic aromatic hydrocarbons (PAHs) including phenanthrene (Phe), pyrene (Pyr), and benzo[a]pyrene (BaP) as a sole carbon and energy source. After cultivated with 50mg/L of each PAH, strain P14 removed 43% Phe, 34% Pyr and 30% BaP in 30 d. Four different hydroxyphenanthrene products derived from Phe by strain P14 (1,2,3,4-hydroxyphenanthrene) were detected using SPME-GC-MS. Strain P14 also was capable of degrading mineral oil with n-alkanes of C17 to C21 carbon chain length. Compared with glucose-grown cells, PAHs-grown cells had decreased contents of shorter-chain length fatty acids (≤ C16:0), increased contents of C18:0, Me-C19:0 and disappeared odd-number carbon chain fatty acids. The contents of unsaturated C19:1, Me-C19:0 increased and C18:0 decreased in mineral oil-grown cells. At the same time, the strain P14 tended to float when cultivated in mineral oil-supplemented liquid medium. The degradation capability of P14 to alkane and PAHs and its floating characteristics will be very helpful for future's application in oil-spill bioremediation.

  15. The presence of aliphatic and aromatic amines in reservoir and canal water as precursors to disinfection by-products.

    PubMed

    Phatthalung, Warangkana Na; Musikavong, Charongpun; Suttinun, Oramas

    2016-09-18

    This research aimed at determining the dimethylamine (DMA), diethylamine (DEA), dibutylamine (DBA), and aromatic aniline (AN) in reservoir and canal water in the U-Tapao River Basin, Songkhla, Thailand. The trihalomethane formation potential (THMFP) and N-nitrosodimethylamine formation potential (NDMA-FP) of the reservoir and canal water were analyzed. Water samples from two reservoirs and raw water from water treatment plants at upstream, midstream, and downstream locations of the canal were collected twice. The analysis of the DMA, DEA, DBA, and AN were conducted using gas chromatography and spectrofluorometry techniques. The DMA, DEA, and DBA levels in the reservoir and canal waters ranged from not detectable (ND) to 10 µg/L and from ND to 21.2 µg/L, respectively. AN was detected from 123 to 129 ng/L and from 112 to 177 ng/L in the reservoir and canal waters, respectively. The DMA, DEA, DBA, and AN exhibited two fluorescent peaks at 230nmEx/345nmEm and 280 nmEx/355nmEm. These two peaks corresponded to the peak positions of tryptophan. Detection limits of DMA, DEA, and DBA for fluorescent analysis were 500 μg/L whereas that of AN and tryptophan were 10 and 0.5 μg/L, respectively. The NDMA-FP measured in all the water samples was lower than the detection limit of 237 ng/L. THMFP ranged from 175 to 248 μg/L and 214 to 429 μg/L was detected in the reservoir and canal waters, respectively. The THMFP/dissolved organic carbon (DOC) of the reservoir and canal waters were comparable within the ranges of 73 to 131 µg THMFP/mg DOC.

  16. Synthesis, crystal structures and magnetic properties of dinuclear copper(II) compounds with NNO tridentate Schiff base ligands and bridging aliphatic diamine and aromatic diimine linkers.

    PubMed

    Rigamonti, Luca; Forni, Alessandra; Pievo, Roberta; Reedijk, Jan; Pasini, Alessandro

    2011-04-07

    The synthesis and the characterization of new dinuclear copper(II) compounds of general formula [(L(a-d))(2)Cu(2)(μ-N-N)](ClO(4))(2) (1-6) with either neutral aliphatic diamine (N-N = piperazine, pip) or aromatic diimine (N-N = 4,4'-bipyridine, 4,4'-bipy) linker are reported. The copper ligands L(-) (L(a-) = (E)-2-((2-aminoethylimino)methyl)phenolate, L(b-) = (E)-2-((2-aminopropylimino)methyl)-phenolate, L(c-) = (E)-2-((2-aminoethylimino)methyl)4-nitrophenolate, L(d-) = (E)-2-((2-aminoethylimino)methyl)4-methoxyphenolate) are NNO tridentate Schiff bases derived from the monocondensation of a substituted salicylaldehyde 5-G-salH (G = NO(2), H, OMe) with ethylenediamine, en, or 1,3-propylenediamine, tn. The crystal structures of compounds [(L(a))(2)Cu(2)(MeOH)(2)(μ-4,4'-bipy)](ClO(4))(2) (1·2MeOH), [(L(b))(2)Cu(2)(MeOH)(2)(μ-4,4'-bipy)](ClO(4))(2) (2·2MeOH), [(L(d))(2)Cu(2)(μ-4,4'-bipy)](ClO(4))(2) (4), [(L(a))(2)Cu(2)(μ-pip)](ClO(4))(2) (5) and [(L(b))(2)Cu(2)(μ-pip)](ClO(4))(2) (6) have been determined, revealing the preferred (e-e)-chair conformation of the bridging piperazine in compounds 5 and 6. The presence of hydrogen-bond-mediated intermolecular interactions, that involve the methanol molecules, yields dimers of dinuclear units for 1·2MeOH, and infinite zig-zag chains for 2·2MeOH. The temperature dependences of the magnetic susceptibilities χ(M)(T) for all compounds were measured, indicating the presence of antiferromagnetic Cu-Cu exchange. For the compounds 2-4 with 4,4'-bipy, the coupling constants J are around -1 cm(-1), while in compound 1 no interaction could be detected. The compounds 5 and 6 with piperazine display higher Cu-Cu magnetic interactions through the σ-bonding backbone of the bridging molecule, with J around -8 cm(-1), and the coupling is favoured by the (e-e)-chair conformation of the diamine ring. The non-aromatic, but shorter, linker piperazine gives rise to stronger Cu-Cu antiferromagnetic couplings than the aromatic, but

  17. Approach to the study of C-glycosyl flavones acylated with aliphatic and aromatic acids from Spergularia rubra by high-performance liquid chromatography-photodiode array detection/electrospray ionization multi-stage mass spectrometry.

    PubMed

    Ferreres, Federico; Gil-Izquierdo, Angel; Vinholes, Juliana; Grosso, Clara; Valentão, Patrícia; Andrade, Paula B

    2011-03-30

    The use of mass spectrometry (MS) coupled to liquid chromatography (LC) as working tool for the study of the C-glycosyl flavones acylated with aliphatic and aromatic acids has allowed the tentative characterization of these compounds in Spergularia rubra and the establishment of the position of the acylation on the sugar moiety of the C-glycosylation by use of MS data. The combination of retention time (Rt), ultraviolet (UV) and MS(n) data of the compounds revealed their C-glycosyl flavone nature, being luteolin, apigenin and chrysoeriol derivatives. Ten non-acylated flavones were identified, from which six are described for the first time (one 7-O-glycosyl-6,8-diC-glycosyl flavone, four 6,8-diC-glycosyl flavones and one 2"-O-glycosyl-6-C-glycosyl flavone). Twenty-six acylated derivatives were also found for the first time. These compounds are grouped in three classes, namely, C-glycosyl flavones acylated with aliphatic acids, with aromatic acids or with a mixed acylation. The first group is characterized by the presence of one 6,8-diC-(acetyl)glycosyl flavone, four 6,8-diC-(malonyl)glycosyl flavones and two 7-O-glycosyl-6,8-diC-(malonyl)glycosyl flavones, while in the second one twelve 6,8-diC-(acyl)glycosyl flavones and two 7-O-glycosyl-6,8-diC-(acyl)glycosyl flavones are described. The last class contained five 6,8-diC-(malonyl,acyl)glycosyl flavones. No previous work has described the presence of C-glycosyl flavones acylated with aliphatic acids in this genus.

  18. Poly(N-arylenebenzimidazole)s via aromatic nucleophilic displacement

    NASA Technical Reports Server (NTRS)

    Connell, John W. (Inventor); Hergenrother, Paul M. (Inventor); Smith, Jr., Joseph G. (Inventor)

    1996-01-01

    Novel poly(N-arylenebenzimidazole)s (PNABls) are prepared by the aromatic nucleophilic displacement reaction of novel di(hydroxyphenyl-N-arylene benzimidazole) monomers with activated aromatic dihalides or activated aromatic dinitro compounds. The polymerizations are carried out in polar aprotic solvents such as N-methyl-2-pyrrolidinone or N,N-dimethylacetamide using alkali metal bases such as potassium carbonate at elevated temperatures under nitrogen. The di(hydroxyphenyl-N-arylenebenzimidazole) monomers are synthesized by reacting phenyl-4-hydroxybenzoate with bis(2-aminoanilino)arylenes in diphenylsulfone. Moderate molecular weight PNABIs of new chemical structures were prepared that exhibit a favorable combination of physical and mechanical properties. The use of the novel di(hydroxyphenyI-N-arylenebenzimidazole)s permits a more economical and easier way to prepare PNABIs than previous routes.

  19. Prediction of source rock origin by chemometric analysis of fourier transform infrared-attenuated total reflectance spectra of oil petroleum: evaluation of aliphatic and aromatic fractions by self-modeling mixture analysis.

    PubMed

    Abbas, Ouissam; Dupuy, Nathalie; Rebufa, Catherine; Vrielynck, Laurence; Kister, Jacky; Permanyer, Albert

    2006-03-01

    This study describes a new methodology for the interpretation of Fourier transform infrared (FT-IR) attenuated total reflectance (ATR) spectra of Algerian, Brazilian, and Venezuelan crude oils. It is based on a comparative study between a chemometric treatment and the classical one, which refers to indices calculation. In fact, the combined use of FT-IR indices and principal component analysis (PCA) has led to the classification of the studied samples in terms of geographic distribution. Quantitative analysis has been successfully realized by the supervised method partial least squares (PLS), which has permitted the prediction of the locations of oils. We have also applied another mathematical processing method, simple-to-use interactive self-modeling mixture analysis (SIMPLISMA), to evaluate the aromatic and aliphatic composition of the oils by extracting pure spectra representative of the different fractions.

  20. A comparison study of aliphatic and aromatic structure directing agents influencing the crystal and electronic structures, and properties of iodoplumbate hybrids: water induced structure conversion and visible light photocatalytic properties.

    PubMed

    Liu, Guang-Ning; Shi, Jian-Ru; Han, Xiao-Jiang; Zhang, Xiao; Li, Ke; Li, Jie; Zhang, Tao; Liu, Qi-Sheng; Zhang, Zhen-Wei; Li, Cuncheng

    2015-07-28

    The introduction of the aliphatic amines en (ethylenediamine), aep (N-(2-aminoethyl)piperazine) and tepa (tetraethylenepentamine), and the aromatic species 2,2'-bipy (2,2'-bipyridine) and dpe (1,2-di(4-pyridyl)ethylene) as structure directing agents (SDAs) into inorganic iodoplumbates affords six hybrids, namely [(Hen)4(H2.5O)2I](PbI6) (1), Cs2n[Pb3I8(en)2]n (2), (H3tepa)n(PbI5)n (3), (H2aep)n(PbI4)n (4), (Et22,2'-bipy)n(Pb2I6)n (5) and (Et2dpe)n(Pb2I6)n (6). 1 contains a discrete octahedral (PbI6)(4-) anion generated under the direction of a novel co-template, [(Hen)4(H2.5O)2I](4+). 2 contains inorganic Cs(+) ions and a novel hybrid anionic layer [Pb3I8(en)2]n(2n-) that has never been encountered in iodoplumbate hybrids. 3 features a zigzag (PbI5)(3-) chain with the charge being compensated by a triprotonated tepa cation. 4 is composed of perovskite sheets of lead(ii) octahedra and aep cations that are generated from tepa via an unprecedented in situ ligand reaction. Both 5 and 6 have (Pb2I6)n(2n-) chains and represent the first example of introducing a 2,2'-bipy or dpe derivative cation in iodoplumbate hybrids, respectively. The comparative study reveals that aliphatic amines and aromatic species contribute differently to the crystal and electronic structures, and the properties of the hybrids. Importantly, 1-4 exhibit interesting water induced structure conversions, while 5 and 6 can be used as heterogeneous photocatalysts for dye wastewater treatment under visible light irradiation.

  1. A Kinetic Modeling study on the Oxidation of Primary Reference Fuel?Toluene Mixtures Including Cross Reactions between Aromatics and Aliphatics

    SciTech Connect

    Sakai, Y; Miyoshi, A; Koshi, M; Pitz, W J

    2008-01-09

    A detailed chemical kinetic model for the mixtures of Primary Reference Fuel (PRF: n-heptane and iso-octane) and toluene has been proposed. This model is divided into three parts; a PRF mechanism [T. Ogura et al., Energy & Fuels 21 (2007) 3233-3239], toluene sub-mechanism and cross reactions between PRF and toluene. Toluene sub-mechanism includes the low temperature kinetics relevant to engine conditions. A chemical kinetic mechanism proposed by Pitz et al. [Proc. the 2nd Joint Meeting of the U.S. Combust. Institute (2001)] was used as a starting model and modified by updating rate coefficients. Theoretical estimations of rate coefficients were performed for toluene and benzyl radical reactions important at low temperatures. Cross-reactions between alkane, alkene, and aromatics were also included in order to account for the acceleration by the addition of toluene into iso-octane recently found in the shock tube study of the ignition delay [Y. Sakai et al, SAE 2007-01-4014 (2007)]. Validations of the model were performed with existing shock tube and flow tube data. The model well predicts the ignition characteristics of toluene and PRF/Toluene mixtures under the wide range of temperatures (500-1700 K) and pressures (2-50 atm). It is found that reactions of benzyl radical with oxygen molecule determine the reactivity of toluene at low temperature. Although the effect of toluene addition to iso-octane is not fully resolved, the reactions of alkene with benzyl radical have the possibility to account for the kinetic interactions between PRF and toluene.

  2. Oxidation of aliphatic, branched chain, and aromatic hydrocarbons by Nocardia cyriacigeorgica isolated from oil-polluted sand samples collected in the Saudi Arabian Desert.

    PubMed

    Le, Thi Nhi-Cong; Mikolasch, Annett; Awe, Susanne; Sheikhany, Halah; Klenk, Hans-Peter; Schauer, Frieder

    2010-06-01

    A soil bacterium isolated from oil-polluted sand samples collected in the Saudi Arabian Desert has been determined as Nocardia cyriacigeorgica, which has a high capacity of degrading and utilizing a broad range of hydrocarbons. The metabolic pathways of three classes of hydrocarbons were elucidated by identifying metabolites in cell-free extracts analyzed by GC/MS and HPLC/UV-Vis in comparison with standard compounds. During tetradecane oxidation, tetradecanol; tetradecanoic acid; dodecanoic acid; decanoic acid could be found as metabolites, indicating a monoterminal degradation pathway of n -alkanes. The oxidation of pristane resulted in the presence of pristanoic acid; 2-methylglutaric acid; 4,8-dimethylnonanoic acid; and 2,6-dimethylheptanoic acid, which give rise to a possible mono- and di-terminal oxidation. In case of sec -octylbenzene, eight metabolites were detected including 5-phenylhexanoic acid; 3-phenylbutyric acid; 2-phenylpropionic acid; beta -methylcinnamic acid; acetophenone; beta -hydroxy acetophenone; 2,3-dihydroxy benzoic acid and succinic acid. From these intermediates a new degradation pathway for sec -octylbenzene was investigated. Our results indicate that N. cyriacigeorgica has the ability to degrade aliphatic and branched chain alkanes as well as alkylbenzene effectively and, therefore, N. cyriacigeorgica is probably a suitable bacterium for biodegradation of oil or petroleum products in contaminated soils.

  3. Chemoselective aromatic azido reduction with concomitant aliphatic azide employing Al/Gd triflates/NaI and ESI-MS mechanistic studies.

    PubMed

    Kamal, Ahmed; Markandeya, Nagula; Shankaraiah, Nagula; Reddy, C Ratna; Prabhakar, S; Reddy, C Sanjeeva; Eberlin, Marcos N; Silva Santos, Leonardo

    2009-07-20

    Aluminium and gadolinium triflates catalyze the chemoselective reduction of aromatic azides to the corresponding amines in combination with sodium iodide. This mild chemoselective method has been applied to the synthesis of various aryl amines, C2-azido-substituted pyrrolo[2,1-c][1,4]benzodiazepines, and fused[2,1-b]quinazolinones by an intramolecular azido reduction tandem cyclization reaction. Interestingly, this methodology selectively reduces aryl azides with enhanced yields and proceeds in shorter reaction times than previous strategies. The mechanistic aspects have been investigated and the intermediates associated with this selective transformation have been intercepted and characterized by online monitoring of the reaction by ESI-MS.

  4. Sediment-associated aliphatic and aromatic hydrocarbons in coastal British Columbia, Canada: concentrations, composition, and associated risks to protected sea otters.

    PubMed

    Harris, Kate A; Yunker, Mark B; Dangerfield, Neil; Ross, Peter S

    2011-10-01

    Sediment-associated hydrocarbons can pose a risk to wildlife that rely on benthic marine food webs. We measured hydrocarbons in sediments from the habitat of protected sea otters in coastal British Columbia, Canada. Alkane concentrations were dominated by higher odd-chain n-alkanes at all sites, indicating terrestrial plant inputs. While remote sites were dominated by petrogenic polycyclic aromatic hydrocarbons (PAHs), small harbour sites within sea otter habitat and sites from an urban reference area reflected weathered petroleum and biomass and fossil fuel combustion. The partitioning of hydrocarbons between sediments and adjacent food webs provides an important exposure route for sea otters, as they consume ∼25% of their body weight per day in benthic invertebrates. Thus, exceedences of PAH sediment quality guidelines designed to protect aquatic biota at 20% of the sites in sea otter habitat suggest that sea otters are vulnerable to hydrocarbon contamination even in the absence of catastrophic oil spills.

  5. Prediction of hydration free energies for aliphatic and aromatic chloro derivatives using molecular dynamics simulations with the OPLS-AA force field.

    PubMed

    Beckstein, Oliver; Iorga, Bogdan I

    2012-05-01

    All-atom molecular dynamics computer simulations were used to blindly predict the hydration free energies of a range of chloro-organic compounds as part of the SAMPL3 challenge. All compounds were parameterized within the framework of the OPLS-AA force field, using an established protocol to compute the absolute hydration free energy via a windowed free energy perturbation approach and thermodynamic integration. Three different approaches to deriving partial charge parameters were pursued: (1) using existing OPLS-AA atom types and charges with minor adjustments of partial charges on equivalent connecting atoms; (2) calculation of quantum mechanical charges via geometry optimization, followed by electrostatic potential (ESP) fitting, using Jaguar at the LMP2/cc-pVTZ(-F) level; and (3) via geometry optimization and CHelpG charges (Gaussian03 at the HF/6-31G* level), followed by two-stage RESP fitting. Protocol 3 generated the most accurate predictions with a root mean square (RMS) error of 1.2 kcal mol(-1) for the entire data set. It was found that the deficiency of the standard OPLS-AA parameters, protocol 1 (RMS error 2.4 kcal mol(-1) overall), was mostly due to compounds with more than three chlorine substituents on an aromatic ring. For this latter subset, the RMS errors were 1.4 kcal mol(-1) (protocol 3) and 4.3 kcal mol(-1) (protocol 1), respectively. We propose new OPLS-AA atom types for aromatic carbon and chlorine atoms in rings with ≥4 Cl-substituents that perform better than the best QM-based approach, resulting in an RMS error of 1.2 kcal mol(-1) for these difficult compounds.

  6. Prediction of hydration free energies for aliphatic and aromatic chloro derivatives using molecular dynamics simulations with the OPLS-AA force field

    NASA Astrophysics Data System (ADS)

    Beckstein, Oliver; Iorga, Bogdan I.

    2012-05-01

    All-atom molecular dynamics computer simulations were used to blindly predict the hydration free energies of a range of chloro-organic compounds as part of the SAMPL3 challenge. All compounds were parameterized within the framework of the OPLS-AA force field, using an established protocol to compute the absolute hydration free energy via a windowed free energy perturbation approach and thermodynamic integration. Three different approaches to deriving partial charge parameters were pursued: (1) using existing OPLS-AA atom types and charges with minor adjustments of partial charges on equivalent connecting atoms; (2) calculation of quantum mechanical charges via geometry optimization, followed by electrostatic potential (ESP) fitting, using Jaguar at the LMP2/cc-pVTZ(-F) level; and (3) via geometry optimization and CHelpG charges (Gaussian03 at the HF/6-31G* level), followed by two-stage RESP fitting. Protocol 3 generated the most accurate predictions with a root mean square (RMS) error of 1.2 kcal mol^{-1} for the entire data set. It was found that the deficiency of the standard OPLS-AA parameters, protocol 1 (RMS error 2.4 kcal mol^{-1} overall), was mostly due to compounds with more than three chlorine substituents on an aromatic ring. For this latter subset, the RMS errors were 1.4 kcal mol^{-1} (protocol 3) and 4.3 kcal mol^{-1} (protocol 1), respectively. We propose new OPLS-AA atom types for aromatic carbon and chlorine atoms in rings with ≥4 Cl-substituents that perform better than the best QM-based approach, resulting in an RMS error of 1.2 kcal mol^{-1} for these difficult compounds.

  7. Laboratory investigation of the contribution of complex aromatic/aliphatic polycyclic hybrid molecular structures to interstellar ultraviolet extinction and infrared emission

    NASA Technical Reports Server (NTRS)

    Arnoult, K. M.; Wdowiak, T. J.; Beegle, L. W.

    2000-01-01

    We have demonstrated by experiment that, in an energetic environment, a simple polycyclic aromatic hydrocarbon (PAH) such as naphthalene will undergo chemical reactions that produce a wide array of more complex species (an aggregate). For a stellar wind of a highly evolved star (post-asymptotic giant branch [post-AGB]), this process would be in addition to what is expected from reactions occurring under thermodynamic equilibrium. A surprising result of that work was that produced in substantial abundance are hydrogenated forms that are hybrids of polycyclic aromatic and polycyclic alkanes. Infrared spectroscopy described here reveals a spectral character for these materials that has much in common with that observed for the constituents of circumstellar clouds of post-AGB stars. It can be demonstrated that a methylene (-CH2-) substructure, as in cycloalkanes, is the likely carrier of the 6.9 microns band emission of dust that has recently been formed around IRAS 22272+5433, NGC 7027, and CPD -56 8032. Ultraviolet spectroscopy previously done with a lower limit of 190 nm had revealed that this molecular aggregate can contribute to the interstellar extinction feature at 2175 angstroms. We have now extended our UV spectroscopy of these materials to 110 nm by a vacuum ultraviolet technique. That work, described here, reveals new spectral characteristics and describes how material newly formed during the late stages of stellar evolution could have produced an extinction feature claimed to exist at 1700 angstroms in the spectrum of HD 145502 and also how the newly formed hydrocarbon material would be transformed/aged in the general interstellar environment. The contribution of this molecular aggregate to the rise in interstellar extinction at wavelengths below 1500 angstroms is also examined. The panspectral measurements of the materials produced in the laboratory, using plasmas of H, He, N, and O to convert the simple PAH naphthalene to an aggregate of complex species

  8. 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.

  9. Aliphatic and polycyclic aromatic hydrocarbons and trace elements as indicators of contamination status near oil and gas platforms in the Sergipe-Alagoas Basin (Southwest Atlantic Ocean)

    NASA Astrophysics Data System (ADS)

    Lourenço, Rafael A.; Araujo Júnior, Marcus A. G.; Meireles Júnior, Ruy O.; Macena, Leandro F.; de A. Lima, Eleine Francioni; Carneiro, Maria Eulalia R.

    2013-12-01

    Oil and gas platforms from Sergipe-Alagoas Basin located in the northeastern region of Brazil do not discharge produced water. However, those platforms can be a potential source of contaminants to the marine environment due to their producing activities. In this study, sediment samples were collected in the vicinity of two offshore oil and gas platforms located in Sergipe-Alagoas Basin (PCM-9 and PGA-1) to evaluate the source and levels of hydrocarbons and trace elements (As, Fe, Al, Ti, Cu, Cd, Zn, Pb, Ni, Mn, Ba, V, Cr and Hg). Also, the potential impact of those platforms on the sediment quality was investigated. Polycyclic aromatic hydrocarbons diagnostic ratios observed in the sediment samples indicated hydrocarbons from pyrogenic source, specifically from biomass combustion. Trace elements As, Cd and Ba recorded concentrations higher than Threshold Effect Levels (TEL) in the sediment nearby the platforms. Also, there was evidence of some samples enriched by barium. Although As, Cd and Ba concentrations were higher than TEL, they most likely corresponded to background levels. The obtained results indicated that activities of the PCM-9 and PGA-1 platforms may not be affecting the quality of nearby sediment.

  10. Responses of CYP450 dependent system to aliphatic and aromatic hydrocarbons body burden in transplanted mussels from South coast of Portugal.

    PubMed

    Lopes, B; Ferreira, A M; Bebianno, M J

    2012-04-01

    Mussels Mytilus galloprovincialis were cross-transplanted at South Portugal from a reference site (site 1) to a site more contaminated with hydrocarbon compounds (site 2), and vice versa, in an active biomonitoring (ABM) concept, to assess the biotransformation capacity catalyzed by the mixed function oxygenase (MFO) system. Total alkanes (TAlk), the unresolved complex mixture (UCM), and total polycyclic aromatic hydrocarbons (TPAHs) concentration increased respectively 6, 4.4 and 4.2 fold relatively to control, in mussels transplanted from site 1 to 2. In the cross-transplant, a 48, 57 and 62% depuration of TAlk, UCM and TPAHs concentrations occurred by the end of the 3-4th week. Petrogenic and biogenic (marine and terrigenous) sources of AHs, and petrogenic and pyrolitic (biomass and oil/fuel incomplete combustion) sources of PAHs were detected at both sites. CYP450, CYT b (5) and NADPH-RED in mussels transplanted from site 1 to 2 were induced from day 0 to 28, with a total increase of 35, 32 and 35%, respectively, while biochemical equilibrium to lesser environmental contamination occurs in mussels transplanted from site 2 to 1. A significant relationship between CYP450 and NADPH-RED was found with TPAH, with distinctive behavior at the two sites. MFO system components increase with exposure time at one site and decreases in the other, reflecting an adaptation to distinct environmental hydrocarbon loads. The ABM strategy proved to be useful to understand the environment real impact on the biochemical responses in mussels' local populations. In this study, CYP450 and NADPH-RED are a useful biomarker for hydrocarbon exposure.

  11. Linear-type S-bridged triruthenium complexes with aliphatic aminothiolate ligands: synthesis, characterization, and properties.

    PubMed

    Matsuura, Noriyuki; Igashira-Kamiyama, Asako; Kawamoto, Tatsuya; Konno, Takumi

    2006-01-09

    Treatment of [RuCl(2)(DMSO)(4)] with 2-aminoethanethiol (Haet) in ethanol gave a dicationic triruthenium complex, [Ru[Ru(aet)(3)](2)]Cl(2) ([1]Cl(2)). Complex [1]Cl(2) was also obtained by treatment of RuCl(3).nH(2)O with excess Haet in water. When [1](2+) was chromatographed on a cation-exchange column of SP-Sephadex C-25, meso (DeltaLambda) and racemic (DeltaDelta/LambdaLambda) isomers of the corresponding tricationic complex, [Ru[Ru(aet)(3)](2)](3+) ([2](3+)), were eluted with aqueous NaNO(3). The racemic isomer of [2](3+) was optically resolved into DeltaDelta and LambdaLambda isomers by using [Sb(2)(R,R-tartrato)(2)](2-) as a resolving agent. The molecular structures of DeltaLambda- and DeltaDelta/LambdaLambda-[2](NO(3))(3) were determined by X-ray crystallography. In these complexes, the central Ru atom is coordinated by six thiolato groups from two terminal fac-(S)-[Ru(aet)(3)] units in an octahedral geometry, forming a linear-type S-bridged triruthenium structure. The spectroelectrochemical studies on the electronic absorption and CD spectra, together with the electrochemical studies, demonstrated that [1](2+) and [2](3+) are interconvertible with each other through a one-electron redox process, retaining the chirality of the triruthenium structure. Their electronic structures were investigated on the basis of EPR and magnetic susceptibility measurements, which indicated that [1](2+) and [2](3+) have spin ground states of S(t) = 0 and S(t) = 1/2, respectively. The corresponding L-cysteinato complex, [Ru[Ru(L-cys-N,S)(3)](2)](3-), which was formed from RuCl(3).nH(2)O and excess L-cysteine (L-H(2)cys) in water followed by air oxidation, is also presented.

  12. Reduction of Aromatic and Heterocyclic Aromatic N-Hydroxylamines by Human Cytochrome P450 2S1

    PubMed Central

    Wang, Kai; Guengerich, F. Peter

    2013-01-01

    Many aromatic amines and heterocyclic aromatic amines (HAAs) are known carcinogens for animals and there is also strong evidence for some in human cancer. The activation of these compounds, including some arylamine drugs, involves N-hydroxylation, usually by cytochrome P450 enzymes (P450) in Family 1 (1A2, 1A1, and 1B1). We previously demonstrated that the bioactivation product of the anti-cancer agent 2-(4-amino-3-methylphenyl)-5-fluorobenzothiazole (5F 203), an N-hydroxylamine, can be reduced by P450 2S1 to its amine precursor under anaerobic conditions and, to a lesser extent, under aerobic conditions (Wang, K., and Guengerich, F. P. (2012) Chem. Res. Toxicol. 25, 1740–1751). In the present study, we tested the hypothesis that P450 2S1 is involved in the reductive biotransformation of known carcinogenic aromatic amines and HAAs. The N-hydroxylamines of 4-aminobiphenyl (4-ABP), 2-naphthylamine (2-NA), and 2-aminofluorene (2-AF) were synthesized and found to be reduced by P450 2S1 under both anaerobic and aerobic conditions. The formation of amines due to P450 2S1 reduction also occurred under aerobic conditions but was less apparent because the competitive disproportionation reactions (of the N-hydroxylamines) also yielded amines. Further, some nitroso and nitro derivatives of the arylamines could also be reduced by P450 2S1. None of the amines tested were oxidized by P450 2S1. These results suggest that P450 2S1 may be involved in the reductive detoxication of several of the activated products of carcinogenic aromatic amines and HAAs. PMID:23682735

  13. Syntheses, Spectral Characterization, and Antimicrobial Studies on the Coordination Compounds of Metal Ions with Schiff Base Containing Both Aliphatic and Aromatic Hydrazide Moieties

    PubMed Central

    Kumar, Dinesh; Chadda, Silky; Sharma, Jyoti; Surain, Parveen

    2013-01-01

    An EtOH solution of 3-ketobutanehydrazide and salicylhydrazide on refluxing in equimolar ratio forms the corresponding Schiff base, LH3 (1). The latter reacts with Mn(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II), Zr(OH)2(IV), MoO2(VI), and UO2(VI) ions in equimolar ratio and forms the corresponding coordination compounds, [M(LH)(MeOH)3] (2, M = Mn, Co, Ni), [Cu(LH)]2 (3), [M′(LH)(MeOH)] (4, M′ = Zn, Cd), [Zr(OH)2(LH)(MeOH)2] (5), [MoO2(LH)(MeOH)] (6), and [UO2(LH)(MeOH)] (7). The coordination compounds have been characterized on the basis of elemental analyses, molar conductance, spectral (IR, reflectance, 1H NMR, ESR) studies, and magnetic susceptibility measurements. They are nonelectrolytes in DMSO. The coordination compounds, except 3, are monomers in diphenyl. They are active against gram-positive bacteria (S. aureus, B. subtilis), gram-negative bacteria (E. coli, P. aeruginosa), and yeast (S. cerevisiae, C. albicans). 1 acts as a dibasic tridentate ONO donor ligand in 2–7 coordinating through its both enolic O and azomethine N atoms. The coordination compounds 2 and 3 are paramagnetic, while rest of the compounds are diamagnetic. A square-planar structure to 3, a tetrahedral structure to 4, an octahedral structure to 2, 6, and 7, and a pentagonal bipyramidal structure to 5 are proposed. PMID:24198736

  14. Effects of dilution of poly(ethylvinylbenzene-divinylbenzene) adsorbent on the adsorption of aliphatic, alicyclic, and aromatic hydrocarbon adsorbates from effective zero to finite surface coverage

    SciTech Connect

    Djordjevic, N.M.; Laub, R.J.

    1988-01-15

    The chromatographic measurement and systematic interpretation of the solidgas partition coefficients K/sub s/ and related thermodynamic properties of a number of hydrocarbon adsorbates (n-pentane through n-octane, cyclohexane, methylcyclohexane, benzene, dichloromethane, chloroform, carbon tetrachloride, tetrahydrofuran, thiophene, and acetone) at effective zero surface coverage with a 1:10 admixture of the title adsorbent-inert diluent from 393 to 443 K are reported. Despite a difference of an order of magnitude in the surface areas of bulk and admixed packings, the adsorbate relative retentions were in good agreement with those found in previous work with neat Porapak Q. The heats of adsorption also coincided to within an experimental error of ca. +- 5%. The GSC technique of elution by characteristic point was then used to derive the finite-concentration adsorption isotherms and isosteric heats of adsorption on n-hexane, cyclohexane, benzene, carbon tetrachloride, and acetone adsorbates with diluted Porapak Q over the temperature range 393-433 K. All exhibited BET Type IV isotherms, as well as changes in the respective isotherm temperature coefficients. The latter is said to be a consequence of the microporous substructure of this adsorbent.

  15. Novel biodegradable aliphatic poly(butylene succinate-co-cyclic carbonate)s with functional carbonate building blocks. 1. Chemical synthesis and their structural and physical characterization.

    PubMed

    Yang, Jing; Hao, Qinghui; Liu, Xiaoyun; Ba, Chaoyi; Cao, Amin

    2004-01-01

    This study presents chemical synthesis, structural, and physical characterization of novel biodegradable aliphatic poly(butylene succinate-co-cyclic carbonate)s P(BS-co-CC) bearing functional carbonate building blocks. First, five kinds of six-membered cyclic carbonate monomers, namely, trimethylene carbonate (TMC), 1-methyl-1,3-trimethylene carbonate (MTMC), 2,2-dimethyl-1,3-trimethylene carbonate (DMTMC), 5-benzyloxytrimethylene carbonate (BTMC), and 5-ethyl-5-benzyloxymethyl trimethylene carbonate (EBTMC), were well prepared from ethyl chloroformate and corresponding diols at 0 degrees C in THF solution with our modified synthetic strategies. Then, a series of new P(BS-co-CC)s were synthesized at 210 degrees C through a simple combination of poly-condensation and ring-opening-polymerization (ROP) of hydroxyl capped PBS macromers and the prepared carbonate monomers, and titanium tetra-isopropoxide Ti(i-OPr)4 was used as a more suitable catalyst of 5 candidate catalysts which could concurrently catalyze poly-condensation and ROP. By means of NMR, GPC, FTIR, and thermal analytical instruments, macromolecular structures and physical properties have been characterized for these aliphatic poly(ester carbonate)s. The experimental results indicated that novel biodegradable P(BS-co-CC)s were successfully synthesized with number average molecular weight Mn ranging from 24.3 to 99.6 KDa and various CC molar contents without any detectable decarboxylation and that the more bulky side group was attached to a cyclic carbonate monomer, the lower reactivity for its copolymerization would be observed. The occurrences of 13C NMR signal splitting of succinyl carbonyl attributed to the BS building blocks could be proposed due to the randomized sequences of BS and CC building blocks. FTIR characterization indicated two distinct absorption bands at 1716 and 1733 approximately 1735 cm(-1), respectively, stemming from carbonyl stretching modes for corresponding BS and CC units. With

  16. Comparison of aliphatic hydrocarbons, polycyclic aromatic hydrocarbons, polychlorinated biphenyls, polybrominated diphenylethers, and organochlorine pesticides in Pacific sanddab (Citharichthys sordidus) from offshore oil platforms and natural reefs along the California coast

    USGS Publications Warehouse

    Gale, Robert W.; Tanner, Michael J.; Love, Milton S.; Nishimoto, Mary M.; Schroeder, Donna M.

    2013-01-01

    Recently, the relative exposure of Pacific sanddab (Citharichthys sordidus) to polycyclic aromatic hydrocarbons (PAHs) at oil-production platforms was reported, indicating negligible exposure to PAHs and no discernible differences between exposures at platforms and nearby natural areas sites. In this report, the potential for chronic PAH exposure in fish is reported, by measurement of recalcitrant, higher molecular weight PAHs in tissues of fish previously investigated for PAH metabolites in bile. A total of 34 PAHs (20 PAHs, 11 alkylated PAHs, and 3 polycyclic aromatic thiophenes) were targeted. In addition, legacy contaminants—polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs),—and current contaminants, polybrominated diphenylethers (PBDEs) linked to endocrine disruption, were measured by gas chromatography with electron-capture or mass spectrometric detection, to form a more complete picture of the contaminant-related status of fishes at oil production platforms in the Southern California Bight. No hydrocarbon profiles or unresolved complex hydrocarbon background were found in fish from platforms and from natural areas, and concentrations of aliphatics were low less than 100 nanograms per gram (ng/g) per component]. Total-PAH concentrations in fish ranged from 15 to 37 ng/g at natural areas and from 8.7 to 22 ng/g at platforms. Profiles of PAHs were similar at all natural and platform sites, consisting mainly of naphthalene and methylnaphthalenes, phenanthrene, fluoranthene, and pyrene. Total-PCB concentrations (excluding non-ortho-chloro-substituted congeners) in fish were low, ranging from 7 to 22 ng/g at natural areas and from 10 to 35 ng/g at platforms. About 50 percent of the total-PCBs at all sites consisted of 11 congeners: 153 > 138/163/164 > 110 > 118 > 15 > 99 > 187 > 149 > 180. Most OCPs, except dichlorodiphenyltrichloroethane (DDT)-related compounds, were not detectable or were at concentrations of less than 1 ng/g in fish. p

  17. Composites of vinyl polystyrylpyridine/bismaleimide-aliphatic ether copolymers

    NASA Technical Reports Server (NTRS)

    Heimbuch, Alvin H.; Rosser, Robert W.; Hsu, Ming-Ta S.

    1989-01-01

    An aliphatic ether bismaleimide was prepared and coreacted with a polyvinylstyrylpyridine (VPSP) oligomer. Studies showed that a controlled ratio of aliphatic to aromatic units in the polymer backbone improved both processibility and interlaminar shear properties for the carbon-fiber composite system. This modified resin was readily soluble in tetrahydrofuran, allowing for better fiber impregnation and thus enhancing adhesive properties and reproducibility. DSC studies have shown a lower cure temperature for the copolymer than for the neat aliphatic bismaleimide, and a glass transition temperature of 260 C, which is more than adequate for most applications. Limited measurements indicated an improvement in toughness (impact resistance).

  18. A Route to Aliphatic Poly(ester)s with Thiol Pendant Groups: From Monomer Design to Editable Porous Scaffolds.

    PubMed

    Fuoco, Tiziana; Finne-Wistrand, Anna; Pappalardo, Daniela

    2016-04-11

    Biodegradable aliphatic polyesters such as poly(lactide) and poly(ε-caprolactone), largely used in tissue engineering applications, lack suitable functional groups and biological cues to enable interactions with cells. Because of the ubiquity of thiol groups in the biological environment and the pliability of thiol chemistry, we aimed to design and synthesize poly(ester) chains bearing pendant thiol-protected groups. To achieve this, 3-methyl-6-(tritylthiomethyl)-1,4-dioxane-2,5-dione, a lactide-type monomer possessing a pendant thiol-protected group, was synthesized. This molecule, when used as a monomer in controlled ring-opening polymerization in combination with lactide and ε-caprolactone, appeared to be a convenient "building block" for the preparation of functionalized aliphatic copolyesters, which were easily modified further. A polymeric sample bearing pyridyl disulfide groups, able to bind a cysteine-containing peptide, was efficiently obtained from a two-step modification reaction. Porous scaffolds were then prepared by blending this latter copolymer sample with poly(L-lactide-co-ε-caprolactone) followed by salt leaching. A further disulfide exchange reaction performed in aqueous medium formed porous scaffolds with covalently linked arginine-glycine-aspartic acid sequences. The scaffolds were characterized by thermal and mechanical tests, and scanning electron microscopy surface images revealed a highly porous morphology. Moreover, a cytotoxicity test indicated good cell viability.

  19. Insights into Thiol-Aromatic Interactions: A Stereoelectronic Basis for S-H/π Interactions.

    PubMed

    Forbes, Christina R; Sinha, Sudipta K; Ganguly, Himal K; Bai, Shi; Yap, Glenn P A; Patel, Sandeep; Zondlo, Neal J

    2017-02-08

    Thiols can engage favorably with aromatic rings in S-H/π interactions, within abiological systems and within proteins. However, the underlying bases for S-H/π interactions are not well understood. The crystal structure of Boc-l-4-thiolphenylalanine tert-butyl ester revealed crystal organization centered on the interaction of the thiol S-H with the aromatic ring of an adjacent molecule, with a through-space Hthiol···Caromatic distance of 2.71 Å, below the 2.90 Å sum of the van der Waals radii of H and C. The nature of this interaction was further examined by DFT calculations, IR spectroscopy, solid-state NMR spectroscopy, and analysis of the Cambridge Structural Database. The S-H/π interaction was found to be driven significantly by favorable molecular orbital interactions, between an aromatic π donor orbital and the S-H σ* acceptor orbital (a π → σ* interaction). For comparison, a structural analysis of O-H/π interactions and of cation/π interactions of alkali metal cations with aromatic rings was conducted. Na(+) and K(+) exhibit a significant preference for the centroid of the aromatic ring and distances near the sum of the van der Waals and ionic radii, as expected for predominantly electrostatic interactions. Li(+) deviates substantially from Na(+) and K(+). The S-H/π interaction differs from classical cation/π interactions by the preferential alignment of the S-H σ* toward the ring carbons and an aromatic π orbital rather than toward the aromatic centroid. These results describe a potentially broadly applicable approach to understanding the interactions of weakly polar bonds with π systems.

  20. Biofiltration of gasoline and diesel aliphatic hydrocarbons.

    PubMed

    Halecky, Martin; Rousova, Jana; Paca, Jan; Kozliak, Evguenii; Seames, Wayne; Jones, Kim

    2015-02-01

    The ability of a biofilm to switch between the mixtures of mostly aromatic and aliphatic hydrocarbons was investigated to assess biofiltration efficiency and potential substrate interactions. A switch from gasoline, which consisted of both aliphatic and aromatic hydrocarbons, to a mixture of volatile diesel n-alkanes resulted in a significant increase in biofiltration efficiency, despite the lack of readily biodegradable aromatic hydrocarbons in the diesel mixture. This improved biofilter performance was shown to be the result of the presence of larger size (C₉-C(12)) linear alkanes in diesel, which turned out to be more degradable than their shorter-chain (C₆-C₈) homologues in gasoline. The evidence obtained from both biofiltration-based and independent microbiological tests indicated that the rate was limited by biochemical reactions, with the inhibition of shorter chain alkane biodegradation by their larger size homologues as corroborated by a significant substrate specialization along the biofilter bed. These observations were explained by the lack of specific enzymes designed for the oxidation of short-chain alkanes as opposed to their longer carbon chain homologues.

  1. Microbial production of aliphatic (S)-epoxyalkanes by using Rhodococcus sp. strain ST-10 styrene monooxygenase expressed in organic-solvent-tolerant Kocuria rhizophila DC2201.

    PubMed

    Toda, Hiroshi; Ohuchi, Takuya; Imae, Ryouta; Itoh, Nobuya

    2015-03-01

    We describe the development of biocatalysis for producing optically pure straight-chain (S)-epoxyalkanes using styrene monooxygenase of Rhodococcus sp. strain ST-10 (RhSMO). RhSMO was expressed in the organic solvent-tolerant microorganism Kocuria rhizophila DC2201, and the bioconversion reaction was performed in an organic solvent-water biphasic reaction system. The biocatalytic process enantioselectively converted linear terminal alkenes to their corresponding (S)-epoxyalkanes using glucose and molecular oxygen. When 1-heptene and 6-chloro-1-hexene were used as substrates (400 mM) under optimized conditions, 88.3 mM (S)-1,2-epoxyheptane and 246.5 mM (S)-1,2-epoxy-6-chlorohexane, respectively, accumulated in the organic phase with good enantiomeric excess (ee; 84.2 and 95.5%). The biocatalysis showed broad substrate specificity toward various aliphatic alkenes, including functionalized and unfunctionalized alkenes, with good to excellent ee. Here, we demonstrate that this biocatalytic system is environmentally friendly and useful for producing various enantiopure (S)-epoxyalkanes.

  2. Microbial Production of Aliphatic (S)-Epoxyalkanes by Using Rhodococcus sp. Strain ST-10 Styrene Monooxygenase Expressed in Organic-Solvent-Tolerant Kocuria rhizophila DC2201

    PubMed Central

    Toda, Hiroshi; Ohuchi, Takuya; Imae, Ryouta

    2015-01-01

    We describe the development of biocatalysis for producing optically pure straight-chain (S)-epoxyalkanes using styrene monooxygenase of Rhodococcus sp. strain ST-10 (RhSMO). RhSMO was expressed in the organic solvent-tolerant microorganism Kocuria rhizophila DC2201, and the bioconversion reaction was performed in an organic solvent-water biphasic reaction system. The biocatalytic process enantioselectively converted linear terminal alkenes to their corresponding (S)-epoxyalkanes using glucose and molecular oxygen. When 1-heptene and 6-chloro-1-hexene were used as substrates (400 mM) under optimized conditions, 88.3 mM (S)-1,2-epoxyheptane and 246.5 mM (S)-1,2-epoxy-6-chlorohexane, respectively, accumulated in the organic phase with good enantiomeric excess (ee; 84.2 and 95.5%). The biocatalysis showed broad substrate specificity toward various aliphatic alkenes, including functionalized and unfunctionalized alkenes, with good to excellent ee. Here, we demonstrate that this biocatalytic system is environmentally friendly and useful for producing various enantiopure (S)-epoxyalkanes. PMID:25556188

  3. Topsoil drying combined with increased sulfur supply leads to enhanced aliphatic glucosinolates in Brassica juncea leaves and roots.

    PubMed

    Tong, Yu; Gabriel-Neumann, Elke; Ngwene, Benard; Krumbein, Angelika; George, Eckhard; Platz, Stefanie; Rohn, Sascha; Schreiner, Monika

    2014-01-01

    The decrease of water availability is leading to an urgent demand to reduce the plants' water supply. This study evaluates the effect of topsoil drying, combined with varying sulfur (S) supply on glucosinolates in Brassica juncea in order to reveal whether a partial root drying may already lead to a drought-induced glucosinolate increase promoted by an enhanced S supply. Without decreasing biomass, topsoil drying initiated an increase in aliphatic glucosinolates in leaves and in topsoil dried roots supported by increased S supply. Simultaneously, abscisic acid was determined, particularly in dehydrated roots, associated with an increased abscisic acid concentration in leaves under topsoil drying. This indicates that the dehydrated roots were the direct interface for the plants' stress response and that the drought-induced accumulation of aliphatic glucosinolates is related to abscisic acid formation. Indole and aromatic glucosinolates decreased, suggesting that these glucosinolates are less involved in the plants' response to drought.

  4. «Оn-off» fluorescent sensors for aromatic analytes based on zinc(II) bis(dipyrromethenate)s

    NASA Astrophysics Data System (ADS)

    Ksenofontov, A. A.; Guseva, G. B.; Antina, E. V.; Nuraneeva, E. N.

    2017-02-01

    This paper presents the results of spectral-luminescence research of binuclear zinc(II) helicates with tetra-, octa-, and decamethylsubstituted 3,3‧-bis(dipyrromethene)s ([Zn2L2]) in binary mixtures of cyclohexane with aromatic hydrocarbons (benzene, toluene, and m-xylene). Structure effects of zinc(II) helicates, and aromaticity criteria of analytes (HOMA, NICS, δ) on the fluorescence quenching efficiency of [Zn2L2] in the presence of aromatic compounds was considered. It was found that decamethylsubstituted 3,3‧-bis(dipyrromethenate)s compared to tetra-, and octamethylsubstituted-analogs shows the highest fluorescence sensitivity to the presence of aromatic compounds. High specificity of spectral-luminescence characteristics changing in the presence of particular aromatic analytes provides the possibility of using [Zn2L2] helicates as new fluorescent sensors of aromatic compounds trace amount (120 ppb to 56 ppm) in organic media.

  5. Aliphatic hydrocarbons and polycyclic aromatic hydrocarbons (PAHs) in sediments collected from the 110 mile hole and along a transect from 58 degrees 58.32'N 1 degree 10.38'W to the inner Moray Firth, Scotland.

    PubMed

    Webster, Lynda; Twigg, Marsailidh; Megginson, Colin; Walsham, Pam; Packer, Gill; Moffat, Colin

    2003-06-01

    Sediments were collected from the 110 mile hole and along a transect from 58 degrees 58.32' N 1 degree 10.38' W to the UK National Marine Monitoring (NMMP) site in the inner Moray Firth, for determination of hydrocarbon concentration and composition. Total PAH concentrations (2- to 6-ring PAHs, parent and branched) were highest at NMMP site 95 and at the associated end of the transect in the inner Moray Firth. PAHs in this area were of predominately pyrolytic origin and could be attributed to urban and industrial activities. The majority of sediments collected in the middle section of the transect had low total PAH concentrations (< 100 ng g(-1) dry weight). The high proportion of naphthalenes and alkylated PAHs in this area suggested a predominately petrogenic input. The GC-FID aliphatic hydrocarbon profiles showed that the majority of sediments, including those in the inner Firth, had a limited petrogenic input. This was supported by the geochemical biomarker profiles, which contained triterpanes typical of Middle Eastern crude oil. Principal component analysis was used to investigate spatial trends in the PAH distributions and demonstrated that there were differences between areas. The NMMP site 95 and transect start and middle sediments were well separated. PCA further confirmed that sediments from the NMMP site 95, the 110 mile hole and the inner Moray Firth (south west) end of the transect contained PAHs from predominately pyrolytic sources, whereas sediments from the north east end (start) and the middle of the transect were typified by a greater petrogenic component.

  6. Linear aliphatic dialkynes as alternative linkers for double-click stapling of p53-derived peptides.

    PubMed

    Lau, Yu Heng; de Andrade, Peterson; McKenzie, Grahame J; Venkitaraman, Ashok R; Spring, David R

    2014-12-15

    We investigated linear aliphatic dialkynes as a new structural class of i,i+7 linkers for the double-click stapling of p53-based peptides. The optimal combination of azido amino acids and dialkynyl linker length for MDM2 binding was determined. In a direct comparison between aliphatic and aromatic staple scaffolds, the aliphatic staples resulted in superior binding to MDM2 in vitro and superior p53-activating capability in cells when using a diazidopeptide derived from phage display. This work demonstrates that the nature of the staple scaffold is an important factor that can affect peptide bioactivity in cells.

  7. Novel biodegradable aliphatic poly(butylene succinate-co-cyclic carbonate)s bearing functionalizable carbonate building blocks: II. Enzymatic biodegradation and in vitro biocompatibility assay.

    PubMed

    Yang, Jing; Tian, Weisheng; Li, Qiaobo; Li, Yang; Cao, Amin

    2004-01-01

    In a previous study, we have reported chemical synthesis of novel aliphatic poly(butylene succinate-co-cyclic carbonate) P(BS-co-CC)s bearing various functionalizable carbonate building blocks, and this work will continue to present our new studies on their enzymatic degradation and in vitro cell biocompatibility assay. First, enzymatic degradation of the novel P(BS-co-CC) film samples was investigated with two enzymes of lipase B Candida Antartic (Novozyme 435) and lipase Porcine Pancreas PPL, and it was revealed that copolymerizing linear poly(butylene succinate) PBS with a functionalizable carbonate building block could remarkably accelerate the enzymatic degradation of a synthesized product P(BS-co-CC), and its biodegradation behavior was found to strongly depend on the overall impacts of several important factors as the cyclic carbonate (CC) comonomer structure and molar content, molar mass, thermal characteristics, morphology, the enzyme-substrate specificity, and so forth. Further, the biodegraded residual film samples and water-soluble enzymatic degradation products were allowed to be analyzed by means of proton nuclear magnetic resonance (1H NMR), gel permeation chromatograph (GPC), differential scanning calorimeter (DSC), attenuated total reflection FTIR (ATR-FTIR), scanning electron microscope (SEM), and liquid chromatograph-mass spectrometry (LC-MS). On the experimental evidences, an exo-type mechanism of enzymatic chain hydrolysis preferentially occurring in the noncrystalline domains was suggested for the synthesized new P(BS-co-CC) film samples. With regard to their cell biocompatibilities, an assay with NIH 3T3 mouse fibroblast cell was conducted using the novel synthesized P(BS-co-CC) films as substrates with respect to the cell adhesion and proliferation, and these new biodegradable P(BS-co-CC) samples were found to exhibit as low cell toxicity as the PLLA control, particularly the two samples of poly(butylene succinate-co-18.7 mol % dimethyl

  8. Effect of different solvent on the photocatalytic activity of ZnIn2S4 for selective oxidation of aromatic alcohols to aromatic aldehydes under visible light irradiation

    NASA Astrophysics Data System (ADS)

    Su, Li; Ye, Xiangju; Meng, Sugang; Fu, Xianliang; Chen, Shifu

    2016-10-01

    A series of ternary chalcogenides, zinc indium sulphide (ZnIn2S4), were synthesized by a simple solvothermal method with different solvents. The structure, textural, and optical properties of the resulting materials were thoroughly characterized by several techniques. The as-prepared ZnIn2S4 samples could all be employed as excellent photocatalysts to activate O2 for selective oxidation of aromatic alcohols to aromatic aldehydes under visible light illumination. The results showed that ZnIn2S4 prepared in ethanol solvent (ZIS-EtOH) exhibited the highest photocatalytic activity among the screened samples. The differences of photocatalytic performance for ZnIn2S4 samples prepared in different media were mainly attributed to the different levels of exposed {0001} special facets caused by the exposure extent of the basic crystal plane. In addition, rad O2- and positive holes were proved to be the main active species during the photocatalytic process. Combined with the previous reports, a possible photocatalytic mechanism for the selective oxidation of benzyl alcohol to benzaldehyde over ZnIn2S4 sample was proposed.

  9. Microbe-aliphatic hydrocarbon interactions in soil: implications for biodegradation and bioremediation.

    PubMed

    Stroud, J L; Paton, G I; Semple, K T

    2007-05-01

    Aliphatic hydrocarbons make up a substantial portion of organic contamination in the terrestrial environment. However, most studies have focussed on the fate and behaviour of aromatic contaminants in soil. Despite structural differences between aromatic and aliphatic hydrocarbons, both classes of contaminants are subject to physicochemical processes, which can affect the degree of loss, sequestration and interaction with soil microflora. Given the nature of hydrocarbon contamination of soils and the importance of bioremediation strategies, understanding the fate and behaviour of aliphatic hydrocarbons is imperative, particularly microbe-contaminant interactions. Biodegradation by microbes is the key removal process of hydrocarbons in soils, which is controlled by hydrocarbon physicochemistry, environmental conditions, bioavailability and the presence of catabolically active microbes. Therefore, the aims of this review are (i) to consider the physicochemical properties of aliphatic hydrocarbons and highlight mechanisms controlling their fate and behaviour in soil; (ii) to discuss the bioavailability and bioaccessibility of aliphatic hydrocarbons in soil, with particular attention being paid to biodegradation, and (iii) to briefly consider bioremediation techniques that may be applied to remove aliphatic hydrocarbons from soil.

  10. S-arylcysteine-keratin adducts as biomarkers of human dermal exposure to aromatic hydrocarbons.

    PubMed

    Kang-Sickel, Juei-Chuan C; Fox, Donii D; Nam, Tae-Gyu; Jayaraj, Karupiah; Ball, Louise M; French, John E; Klapper, David G; Gold, Avram; Nylander-French, Leena A

    2008-04-01

    To measure biomarkers of skin exposure to ubiquitous industrial and environmental aromatic hydrocarbons, we sought to develop an ELISA to quantitate protein adducts of metabolites of benzene and naphthalene in the skin of exposed individuals. We hypothesized that electrophilic arene oxides formed by CYP isoforms expressed in the human skin react with nucleophilic sites on keratin, the most abundant protein in the stratum corneum that is synthesized de novo during keratinocyte maturation and differentiation. The sulfhydryl groups of cysteines in the head region of the keratin proteins 1 (K1) and 10 (K10) are likely targets. The following synthetic S-arylcysteines were incorporated into 10-mer head sequences of K1 [GGGRFSS( S-aryl-C)GG] and K10 [GGGG( S-aryl-C)GGGGG] to form the predicted immunogenic epitopes for antibody production for ELISA: S-phenylcysteine-K1 (SPK1), S-phenylcysteine-K10 (SPK10), S-(1-naphthyl)cysteine-K1 (1NK1), S-(1-naphthyl)cysteine-K10 (1NK10), S-(2-naphthyl)cysteine-K1 (2NK1), and S-(2-naphthyl)cysteine-K10 (2NK10). Analysis by ELISA was chosen based on its high throughput and sensitivity, and low cost. The synthetic modified oligopeptides, available in quantity, served both as immunogens and as chemical standards for quantitative ELISA. Polyclonal rabbit antibodies produced against the naphthyl-modified keratins reacted with their respective antigens with threshold sensitivities of 15-31 ng/mL and high specificity over a linear range up to 500 ng/mL. Anti- S-phenylcysteine antibodies were not sufficiently specific or sensitive toward the target antigens for use in ELISA under our experimental conditions. In dermal tape-strip samples collected from 13 individuals exposed to naphthalene-containing jet fuel, naphthyl-conjugated peptides were detected at levels from 0.343 +/- 0.274 to 2.34 +/- 1.61 pmol adduct/microg keratin but were undetectable in unexposed volunteers. This is the first report of adducts of naphthalene (or of any polycyclic

  11. Desorption of polycyclic aromatic hydrocarbons (PAH`s) from calcite and quartz sediments to seawater

    SciTech Connect

    Sutton, P.L.; Van Vleet, E.S.

    1996-12-31

    Polycyclic aromatic hydrocarbons (PAH`s) are ubiquitous hydrophobic organic pollutants in the marine environment. Many of the PAM`s are classified as possible carcinogens or mutagens, therefore they are of considerable concern to human and environmental health. The highest concentrations are found in coastal regions due to anthropogenic activities including oil spills, tanker operations, incomplete fossil fuel combustion and runoff. The sources and distribution of PAM`s in sediments are fairly well known, while the fate and transport of PAH`s in the marine environment are less known. Desorption is an important factor influencing the fate and transport of hydrophobic molecules at the seawater/sediment interface. The desorption of PAH`s from contaminated marine sediments to the water column/pore water affects the availability of the pollutant to biota. The sorption of PAH`s is determined in part by the organic carbon content of the sediments. The presence of dissolved organic carbon (DOC) in the water column may also influence sorption of hydrophobic molecules. DOC may play an important role in the fate and transport of PAH`s in coastal regions where DOC concentrations are highest. This study presents the results of the desorption of nine PAHs from sediments to seawater. Factors observed included carbon content of sediments, sediment mineralogy, fulvic acid addition to seawater and dissolved organic carbon in seawater.

  12. Syntheses and physical characterization of new aliphatic triblock poly(L-lactide-b-butylene succinate-b-L-lactide)s bearing soft and hard biodegradable building blocks.

    PubMed

    Ba, Chaoyi; Yang, Jing; Hao, Qinghui; Liu, Xiaoyun; Cao, Amin

    2003-01-01

    This study presents chemical syntheses and physical characterization of a new aliphatic poly(L-lactide-b-butylene succinate-b-L-lactide) triblock copolyester with soft and hard biodegradable building blocks. First, poly(butylene succinate) (PBS) prepolymers terminated with hydroxyl functional groups were synthesized through melt polycondensation from succinic acid and 1,4-butanediol. Further, a series of new PLLA-b-PBS-b-PLLA triblock copolyesters bearing various average PLLA block lengths were prepared via ring opening polymerization of L-lactide with the synthesized hydroxyl capped PBS prepolymer (Mn = 4.9 KDa) and stannous octanoate as the macroinitiator and catalyst, respectively. By means of GPC, NMR, FTIR, DSC, TGA, and wide-angle X-ray diffractometer (WAXD), the macromolecular structures and physical properties were intensively studied for these synthesized PBS prepolymer and PLLA-b-PBS-b-PLLA triblock copolyesters. 13C NMR and GPC experimental results confirmed the formation of sequential block structures without any detectable transesterification under the present experimental conditions, and the molecular weights of triblock copolyesters could be readily regulated by adjusting the feeding molar ratio of L-lactide monomer to the PBS macroinitiator. DSC measurements showed all single glass transitions, and their glass transition temperatures were found to be between those of PLLA and PBS, depending on the lengths of PLLA blocks. It was noteworthy that the segmental flexibilities of the hard PLLA blocks were found to be remarkably enhanced by the more flexible PBS block partner, and the PBS and PLLA building blocks were well mixed in the amorphous regions. Results of TGA analyses indicated that thermal degradation and stabilities of the PLLA blocks strongly depended on the average PLLA block lengths of triblock copolyesters. In addition, FTIR and WAXD results showed the coexistence of the assembled PLLA and PBS crystal structures when the average PLLA block

  13. Guided desaturation of unactivated aliphatics

    NASA Astrophysics Data System (ADS)

    Voica, Ana-Florina; Mendoza, Abraham; Gutekunst, Will R.; Fraga, Jorge Otero; Baran, Phil S.

    2012-08-01

    The excision of hydrogen from an aliphatic carbon chain to produce an isolated olefin (desaturation) without overoxidation is one of the most impressive and powerful biosynthetic transformations for which there are no simple and mild laboratory substitutes. The versatility of olefins and the range of reactions they undergo are unsurpassed in functional group space. Thus, the conversion of a relatively inert aliphatic system into its unsaturated counterpart could open new possibilities in retrosynthesis. In this article, the invention of a directing group to achieve such a transformation under mild, operationally simple, metal-free conditions is outlined. This ‘portable desaturase’ (TzoCl) is a bench-stable, commercial entity (Aldrich, catalogue number L510092) that is facile to install on alcohol and amine functionalities to ultimately effect remote desaturation, while leaving behind a synthetically useful tosyl group.

  14. Aliphatic-Aromatic Heterocyclics as Potential Thermoplastics for Composite Matrices

    NASA Technical Reports Server (NTRS)

    Delano, C. B.; Kiskiras, C. J.

    1984-01-01

    The successful development of impact- and solvent-resistant thermoplastic systems for glass graphite composites is particularly attractive because of the demonstrated streamlined manufacturability of such composites. Hypothetically, thermoplastics only require simple heating and cooling cycles for component manufacture, whereas thermosets require precise, and possibly extended heating schedules which must be consistent with the cure chemistry. The sensitivity of the majority of existing thermoplastics to aircraft fluids and other solvents preempts their serious consideration in aircraft components. This is the basic reason that Acurex proposed insolubility in common solvents as the starting point. The target properties are summarized as follows: (1) prepreg properties (use of conventional prepregging equipment, 6+ months shelf stability, processability, and thermoformability); and (2) composite properties (-54 C to 93 C capability, good mechanical properties, good environmental properties, and impact resistance).

  15. Aromatic/aliphatic diamine derivatives for advanced compositions and polymers

    NASA Technical Reports Server (NTRS)

    Delozier, Donovan M. (Inventor); Watson, Kent A. (Inventor); Connell, John W. (Inventor); Smith, Jr., Joseph G. (Inventor)

    2010-01-01

    Novel compositions of matter comprise certain derivatives of 9,9-dialkyl fluorene diamine (AFDA). The resultant compositions, whether compositions of matter or monomers that are subsequently incorporated into a polymer, are unique and useful in a variety of applications. Useful applications of AFDA-based material include heavy ion radiation shielding components and components of optical and electronic devices.

  16. Aliphatic hydrocarbons of the fungi.

    NASA Technical Reports Server (NTRS)

    Weete, J. D.

    1972-01-01

    Review of studies of aliphatic hydrocarbons which have been recently detected in the spores of phytopathogenic fungi, and are found to be structurally very similar to the alkanes of higher plants. It appears that the hydrocarbon components of the few mycelial and yeast forms reported resemble the distribution found in bacteria. The occurence and distribution of these compounds in the fungi is discussed. Suggested functional roles of fungal spore alkanes are presented.

  17. Polycyclic Aromatic Hydrocarbons in the Mainstream Smoke of Popular U.S. Cigarettes.

    PubMed

    Vu, An T; Taylor, Kenneth M; Holman, Matthew R; Ding, Yan S; Hearn, Bryan; Watson, Clifford H

    2015-08-17

    The mainstream smoke yields of 14 polycyclic aromatic hydrocarbons (PAHs) were determined for 50 commercial U.S. cigarettes using a validated GC/MS method with the International Organization of Standardization (ISO) and Canadian Intense (CI) smoking machine regimens. PAH mainstream smoke deliveries vary widely among the commercial cigarettes with the ISO smoking regimen primarily because of differing filter ventilation. The more abundant, lower molecular weight PAHs such as naphthalene, fluorene, and phenanthrene predominantly comprise the total PAH yields. In contrast, delivery yields of high molecular weight PAHs such as benzo[b]fluoranthene, benzo[e]pyrene, benzo[k]fluoranthene, and benzo[a]pyrene (BaP) are much lower. Comparative analysis of PAHs deliveries shows brand specific differences. Correlation analysis shows strong positive associations between BaP and most of the other PAHs as well as total PAHs. The results suggest that BaP may be a representative marker for other PAH constituents in cigarette smoke generated from similarly blended tobacco, particularly those PAHs with similar molecular weights and chemical structures.

  18. Polycyclic aromatic hydrocarbons from U.S. and Antarctic sites analyzed with synchronous fluorescence spectrometry

    SciTech Connect

    Amick, E.N.; Pollard, J.E.; Engelmann, W.H.; Brown, K.W.; Alarie, J.P.; Watts, W.; Vo-Dinh, T.; Akindele, F.M.; Crockett, A.B.

    1995-12-31

    Synchronous ultraviolet-visible (UV-vis) fluorescence spectrometry is currently being evaluated as a field screening technology by the US Environmental Protection Agency`s (EPA) Environmental Monitoring Systems Laboratory in Las Vegas, Nevada (EMSL-LV). This method can provide compound or class-selective results on site at a reasonable cost. A prototype field-portable spectrofluorometer capable of excitation, emission, and synchronous scans was field tested at the American Creosote Works Superfund Site (a wood preservation facility) in Jackson, Tennessee. The instrument was also tested in the laboratory with sediment samples collected from Antarctica. The UV-vis fluorescence spectra of various polycyclic aromatic hydrocarbons (PAHs) were clearly seen in the synchronous spectra of soil samples extracted on site at American Creosote Works. The spectra for the Antarctic sediment samples were nearly identical to that of motor oil. The results of this study demonstrate the utility of synchronous fluorescence to provide evidence of the presence and identity of hydrocarbon contamination in environmental samples. The technique allows flexibility in selection of optimum extraction and instrumental procedures for site-specific matrices.

  19. The role of cytochrome P450s in polycyclic aromatic hydrocarbon carcinogenesis

    SciTech Connect

    Polzer, R.J.

    1993-01-01

    Metabolic activation of polycyclic aromatic hydrocarbons (PAH) to carcinogenic diol epoxides has been determined to be a critical step in tumor initiation by PAH. The key enzyme(s) involved in the metabolic activation are members of the cytochrome P450 superfamily. Two distinct isoforms of cytochrome P450 have been determined to be induced upon treatment of cells in culture with benzo(a)pyrene (B(a)P) by use of Immobilized Artificial Membrane Column High Performance Liquid Chromatography, Western blotting, Northern blotting, and in vitro metabolism studies. Cytochrome P4501A is involved in the metabolism of PAH in the human hepatoma cell line, HepG2; the human mammary carcinoma cell line, MCF-7; and the mouse hepatoma cell line; Hepa-1; whereas cytochrome P450EF is involved in this metabolism in both secondary hamster and mouse embryo cell cultures. Induction of cytochrome P450s by B(a)P generally leads to an increased metabolism of tritiated B(a)P, DMBA, and DB(a,1)P to water-soluble metabolities and to the formation of PAH-DNA adducts, suggesting that induction by B(a)P alters the metabolism of PAH to metabolic activation. DMBA induction of cytochrome P450s leads to various changes in metabolism and PAH-DNA binding and these changes were both cell and PAH specific. These results suggest that DMBA can shift metabolism of certain PAH towards metabolic activation in some cells, while in other cells DMBA or one of its metabolities can compete with other PAH for metabolic activation. UDP-glucuronosyl-transferase and epoxide hydrase do not have significant roles in detoxifying proximate or ultimate carcinogenic PAH metabolites, however, sulfotransferase and glutathione-S-transferase do detoxify proximate and ultimate carcinogenic metabolities in the HepG2 cell line. Finally, attempts to inhibit B(a)P metabolism and DNA-binding in intact cells in culture through conjugation of inhibitory cytochrome P4501A1 antibodies to insulin or folic acid were examined.

  20. Sources and deposition of polycyclic aromatic hydrocarbons to Western U.S. national parks.

    PubMed

    Usenko, Sascha; Simonich, Staci L Massey; Hageman, Kimberly J; Schrlau, Jill E; Geiser, Linda; Campbell, Don H; Appleby, Peter G; Landers, Dixon H

    2010-06-15

    Seasonal snowpack, lichens, and lake sediment cores were collected from fourteen lake catchments in eight western U.S. National Parks and analyzed for sixteen polycyclic aromatic hydrocarbons (PAHs) to determine their current and historical deposition, as well as to identify their potential sources. Seasonal snowpack was measured to determine the current wintertime atmospheric PAH deposition; lichens were measured to determine the long-term, year around deposition; and the temporal PAH deposition trends were reconstructed using lake sediment cores dated using (210)Pb and (137)Cs. The fourteen remote lake catchments ranged from low-latitude catchments (36.6 degrees N) at high elevation (2900 masl) in Sequoia National Park, CA to high-latitude catchments (68.4 degrees N) at low elevation (427 masl) in the Alaskan Arctic. Over 75% of the catchments demonstrated statistically significant temporal trends in SigmaPAH sediment flux, depending on catchment proximity to source regions and topographic barriers. The SigmaPAH concentrations and fluxes in seasonal snowpack, lichens, and surficial sediment were 3.6 to 60,000 times greater in the Snyder Lake catchment of Glacier National Park than the other 13 lake catchments. The PAH ratios measured in snow, lichen, and sediment were used to identify a local aluminum smelter as a major source of PAHs to the Snyder Lake catchment. These results suggest that topographic barriers influence the atmospheric transport and deposition of PAHs in high-elevation ecosystems and that PAH sources to these national park ecosystems range from local point sources to diffuse regional and global sources.

  1. Aliphatic amine responsive organogel system based on a simple naphthalimide derivative.

    PubMed

    Cao, Xinhua; Zhang, Tingting; Gao, Aiping; Li, Keli; Cheng, Qiuli; Song, Lijuan; Zhang, Min

    2014-09-07

    A new gelator 1 based on a simple naphthalimide derivative was synthesized and fully characterized. It was found that the organogel 1 was formed only in a mixed solvent of methanol and H2O (1/1, v/v). The organogel was thoroughly characterized by using various microscopic techniques including field-emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), and UV-vis, fluorescence and Fourier transform infrared (FTIR) spectroscopy. Hydrogen bonds were the main driving force for the organogel formation. Interestingly, the organogel 1 exhibited the ability to distinguish aliphatic amines from aromatic amines. The gel state and fluorescence emission intensity were both changed after two minutes after the addition of aliphatic amines. This organogel system could be applied in the detection of aliphatic amine pollutants.

  2. 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.

  3. Polybenzimidazole via aromatic nucleophilic displacement

    NASA Technical Reports Server (NTRS)

    Connell, John W. (Inventor); Hergenrother, Paul M. (Inventor); Smith, Joseph G. (Inventor)

    1994-01-01

    Di(hydroxyphenyl)benzimidazole monomers were prepared from phenyl-4-hydroxybenzoate and aromatic bis(o-diamine)s. These monomers were used in the synthesis of soluble polybenzimidazoles. The reaction involved the aromatic nucleophilic displacement of various di(hydroxyphenyl)benzimidazole monomers with activated aromatic dihalides or activated aromatic dinitro compounds in the presence of an alkali metal base. These polymers exhibited lower glass transition temperatures, improved solubility, and better compression moldability over their commercial counterparts.

  4. Anaerobic digestion of aliphatic polyesters.

    PubMed

    Šmejkalová, Pavla; Kužníková, Veronika; Merna, Jan; Hermanová, Soňa

    2016-01-01

    Anaerobic processes for the treatment of plastic materials waste represent versatile and effective approach in environmental protection and solid waste management. In this work, anaerobic biodegradability of model aliphatic polyesters, poly(L-lactic acid) (PLA), and poly(ɛ-caprolactone) (PCL), in the form of powder and melt-pressed films with varying molar mass, was studied. Biogas production was explored in batch laboratory trials at 55 ± 1°C under a nitrogen atmosphere. The inoculum used was thermophilic digested sludge (total solids concentration of 2.9%) from operating digesters at the Central Waste Water Treatment Plant in Prague, Czech Republic. Methanogenic biodegradation of PCLs typically yielded from 54 to 60% of the theoretical biogas yield. The biodegradability of PLAs achieved from 56 to 84% of the theoretical value. High biogas yield (up to 677 mL/g TS) with high methane content (more than 60%), comparable with conventionally processed materials, confirmed the potential of polyester samples for anaerobic treatment in the case of their exploitation in agriculture or as a packaging material in the food industry.

  5. Palladium-catalyzed highly regioselective hydroaminocarbonylation of aromatic alkenes to branched amides.

    PubMed

    Zhu, Jinping; Gao, Bao; Huang, Hanmin

    2017-03-22

    Pd(t-Bu3P)2 has been successfully identified as an efficient catalyst for the hydroaminocarbonylation of aromatic alkenes to branched amides under relatively mild reaction conditions. With hydroxylamine hydrochloride as an additive, both aliphatic and aromatic amines could be used as coupling partners for the present reaction, leading to production of branched amides in high yields with excellent regioselectivities.

  6. Haloacetic acid and trihalomethane formation from the chlorination and bromination of aliphatic beta-dicarbonyl acid model compounds.

    PubMed

    Dickenson, Eric R V; Summers, R Scott; Croué, Jean-Philippe; Gallard, Hervé

    2008-05-01

    While it is known that resorcinol- and phenol-type aromatic structures within natural organic matter (NOM) react during drinking water chlorination to form trihalomethanes (THMs), limited studies have examined aliphatic-type structures as THM and haloacetic acid (HAA) precursors. A suite of aliphatic acid model compounds were chlorinated and brominated separately in controlled laboratory-scale batch experiments. Four and two beta-dicarbonyl acid compounds were found to be important precursors for the formation of THMs (chloroform and bromoform (71-91% mol/mol)), and dihaloacetic acids (DXAAs) (dichloroacetic acid and dibromoacetic acid (5-68% mol/mol)), respectively, after 24 h at pH 8. Based upon adsorbable organic halide formation, THMs and DXAAs, and to a lesser extent mono and trihaloacetic acids, were the majority (> 80%) of the byproducts produced for most of the aliphatic beta-dicarbonyl acid compounds. Aliphatic beta-diketone-acid-type and beta-keto-acid-type structures could be possible fast- and slow-reacting THM precursors, respectively, and aliphatic beta-keto-acid-type structures are possible slow-reacting DXAA precursors. Aliphatic beta-dicarbonyl acid moieties in natural organic matter, particularly in the hydrophilic fraction, could contribute to the significant formation of THMs and DXAAs observed after chlorination of natural waters.

  7. Physicochemical properties of polycyclic aromatic hydrocarbons: Aqueous solubilities, n-octanol/water partition coefficients, and Henry`s law constants

    SciTech Connect

    Maagd, P.G.J. de; Opperhuizen, A.; Sijm, D.T.H.M.; Hulscher, D.T.E.M. ten; Heuvel, H. van den

    1998-02-01

    Aqueous solubilities, n-octanol/water partition coefficients (K{sub ow}S), and Henry`s law constants were determined for a range of polycyclic aromatic hydrocarbons (PAHs) using a generator-column, slow-stirring, and gas-purge method, respectively. The currently obtained data were compared to available literature data. For seven of the PAHs no K{sub ow}S previously were determined with the slow-stirring method. For four of the PAHs the present study reports the first experimental Henry`s law constants. Relationships between subcooled liquid solubilities, K{sub ow}S, and Henry`s law constants as a function of molar volume are discussed. A consistent data set was obtained, for which an excellent correlation was found between subcooled liquid solubility and molar volume. A linear fit did not accurately describe the relationship between log K{sub ow} and molar volume. This is probably due to a decreasing solubility in n-octanol with increasing molar volume. Finally, a high correlation was found between Henry`s law constant and molar volume. The presently obtained dataset can be used to predict the fate and behavior of unsubstituted homocyclic PAHs.

  8. Aliphatic amines in the Murchison meteorite

    NASA Technical Reports Server (NTRS)

    Jungclaus, G.; Cronin, J. R.; Moore, C. B.; Yuen, G. U.

    1976-01-01

    The paper reports on the determination of aliphatic amines in water extracts of the Murchison meteorite. The amines were analyzed by gas chromatography both as the free amines and as 2,4-dinitrophenyl (DNP) derivatives. The results give evidence for the presence of all of the possible primary aliphatic monoamines (eight) with fewer than five carbon atoms. Two of the seven possible secondary or tertiary aliphatic monoamines were identified. The identified primary amines total 80 nmol per g meteorite, and seem to be chemically or physically trapped in the meteorite. Similarities between the water-extractable amines and amino acids suggest that (1) a simple carbon compound, methane, for example, is the precursor of meteorite amines and amino acids, and (2) both amines and amino acids are extracted from the meteorite both as such and in the form of acid-hydrolyzable derivative or precursor species.

  9. Intermolecular interactions of oligothienoacenes: Do S⋯S interactions positively contribute to crystal structures of sulfur-containing aromatic molecules?

    PubMed

    Tsuzuki, Seiji; Orita, Hideo; Sato, Naoki

    2016-11-07

    Intermolecular interactions in the crystals of tetra- and penta-thienoacene were studied using ab initio molecular orbital calculations for evaluating the magnitude of characteristic S⋯S interactions with great attention paid to their origin. The interactions between the π-stacked neighboring molecules are significantly greater than those between the neighboring molecules exhibiting the S⋯S contact, although it has sometimes been claimed that the S⋯S interactions play important roles in adjusting the molecular arrangement of sulfur-containing polycyclic aromatic molecules in the crystals owing to short S⋯S contacts. The coupled cluster calculations with single and double substitutions with noniterative triple excitation interaction energies at the basis set limit estimated for the π-stacked and S⋯S contacted neighboring molecules in the tetrathienoacene crystal are -11.17 and -4.27 kcal/mol, respectively. Those for π-stacked molecules in the pentathienoacene crystal is -14.38 kcal/mol, while those for S⋯S contacted molecules are -7.02 and -6.74 kcal/mol. The dispersion interaction is the major source of the attraction between the π-stacked and S⋯S contacted molecules, while the orbital-orbital interactions are repulsive: The orbital-orbital interactions, which are significant for charge carrier transport properties, are not much more than the results of the short S⋯S contact caused by the strong dispersion interactions. Besides, the intermolecular interaction energy calculated for a trithienoacene dimer has strong orientation dependence.

  10. CCN activity of aliphatic amine secondary aerosol

    NASA Astrophysics Data System (ADS)

    Tang, X.; Price, D.; Praske, E.; Vu, D.; Purvis-Roberts, K.; Silva, P. J.; Cocker, D. R., III; Asa-Awuku, A.

    2014-01-01

    Aliphatic amines can form secondary aerosol via oxidation with atmospheric radicals (e.g. hydroxyl radical and nitrate radical). The particle composition can contain both secondary organic aerosol (SOA) and inorganic salts. The fraction of organic to inorganic materials in the particulate phase influences aerosol hygroscopicity and cloud condensation nuclei (CCN) activity. SOA formed from trimethylamine (TMA) and butylamine (BA) reactions with hydroxyl radical (OH) is composed of organic material of low hygroscopicity (single hygroscopicity parameter, κ ≤ 0.25). Secondary aerosol formed from the tertiary aliphatic amine (TMA) with N2O5 (source of nitrate radical, NO3), contains less volatile compounds than the primary aliphatic amine (BA) aerosol. TMA + N2O5 form semi-volatile organics in low RH conditions that have κ ~ 0.20, indicative of slightly soluble organic material. As RH increases, several inorganic amine salts are formed as a result of acid-base reactions. The CCN activity of the humid TMA-N2O5 aerosol obeys Zdanovskii, Stokes, and Robinson (ZSR) ideal mixing rules. Higher CCN activity (κ > 0.3) was also observed for humid BA+N2O5 aerosols compared with dry aerosol (κ ~ 0.2), as a result of the formation of inorganic salts such as NH4NO3 and butylamine nitrate (C4H11N · HNO3). Compared with TMA, BA+N2O5 reactions produce more volatile aerosols. The BA+N2O5 aerosol products under humid experiments were found to be very sensitive to the temperature within the stream-wise continuous flow thermal gradient CCN counter. The CCN counter, when set above a 21 °C temperature difference, evaporates BA+N2O5 aerosol formed at RH ≥ 30%; κ ranges from 0.4 to 0.7 and is dependent on the instrument supersaturation (ss) settings. The aerosol behaves non-ideally, hence simple ZSR rules cannot be applied to the CCN results from the primary aliphatic amine system. Overall, aliphatic amine aerosol systems κ ranges from 0.2 < κ < 0.7. This work indicates that

  11. 40 CFR 721.6140 - Dialkyldithiophosphoric acid, aliphatic amine salt.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ..., aliphatic amine salt. 721.6140 Section 721.6140 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.6140 Dialkyldithiophosphoric acid, aliphatic amine salt. (a) Chemical... as a dialkyldithiophosphoric acid, aliphatic amine salt (P-90-1839) is subject to reporting...

  12. 40 CFR 721.6140 - Dialkyldithiophosphoric acid, aliphatic amine salt.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ..., aliphatic amine salt. 721.6140 Section 721.6140 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.6140 Dialkyldithiophosphoric acid, aliphatic amine salt. (a) Chemical... as a dialkyldithiophosphoric acid, aliphatic amine salt (P-90-1839) is subject to reporting...

  13. 40 CFR 721.6140 - Dialkyldithiophosphoric acid, aliphatic amine salt.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ..., aliphatic amine salt. 721.6140 Section 721.6140 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.6140 Dialkyldithiophosphoric acid, aliphatic amine salt. (a) Chemical... as a dialkyldithiophosphoric acid, aliphatic amine salt (P-90-1839) is subject to reporting...

  14. 40 CFR 721.6140 - Dialkyldithiophosphoric acid, aliphatic amine salt.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ..., aliphatic amine salt. 721.6140 Section 721.6140 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.6140 Dialkyldithiophosphoric acid, aliphatic amine salt. (a) Chemical... as a dialkyldithiophosphoric acid, aliphatic amine salt (P-90-1839) is subject to reporting...

  15. 40 CFR 721.6140 - Dialkyldithiophosphoric acid, aliphatic amine salt.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ..., aliphatic amine salt. 721.6140 Section 721.6140 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.6140 Dialkyldithiophosphoric acid, aliphatic amine salt. (a) Chemical... as a dialkyldithiophosphoric acid, aliphatic amine salt (P-90-1839) is subject to reporting...

  16. 40 CFR 721.10534 - Brominated aliphatic alcohol (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Brominated aliphatic alcohol (generic... Specific Chemical Substances § 721.10534 Brominated aliphatic alcohol (generic). (a) Chemical substance and... aliphatic alcohol (PMN P-12-260) is subject to reporting under this section for the significant new...

  17. 40 CFR 721.10534 - Brominated aliphatic alcohol (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Brominated aliphatic alcohol (generic... Specific Chemical Substances § 721.10534 Brominated aliphatic alcohol (generic). (a) Chemical substance and... aliphatic alcohol (PMN P-12-260) is subject to reporting under this section for the significant new...

  18. 40 CFR 721.10199 - Substituted aliphatic amine (generic).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Substituted aliphatic amine (generic... Specific Chemical Substances § 721.10199 Substituted aliphatic amine (generic). (a) Chemical substance and... aliphatic amine (PMN P-06-702) is subject to reporting under this section for the significant new...

  19. 40 CFR 721.2270 - Aliphatic dicarboxylic acid salt.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Aliphatic dicarboxylic acid salt. 721... Substances § 721.2270 Aliphatic dicarboxylic acid salt. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as aliphatic dicarboxylic...

  20. 40 CFR 721.2270 - Aliphatic dicarboxylic acid salt.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Aliphatic dicarboxylic acid salt. 721... Substances § 721.2270 Aliphatic dicarboxylic acid salt. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as aliphatic dicarboxylic...

  1. 40 CFR 721.2270 - Aliphatic dicarboxylic acid salt.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Aliphatic dicarboxylic acid salt. 721... Substances § 721.2270 Aliphatic dicarboxylic acid salt. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as aliphatic dicarboxylic...

  2. 40 CFR 721.2270 - Aliphatic dicarboxylic acid salt.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Aliphatic dicarboxylic acid salt. 721... Substances § 721.2270 Aliphatic dicarboxylic acid salt. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as aliphatic dicarboxylic...

  3. THE PHOTOTOXICITY OF POLYCYCLIC AROMATIC HYDROCARBONS

    EPA Science Inventory

    The U.S. Environmental Protection Agency (EPA) continues to be interested in developing methods for the detection of polycyclic aromatic hydrocarbons (PAHS) in the environment. Polycyclic aromatic hydrocarbons (PAHS) are common contaminants in our environment. Being major product...

  4. Renaissance of Aliphatic Polycarbonates: New Techniques and Biomedical Applications

    PubMed Central

    Xu, Jianwen; Feng, Ellva; Song, Jie

    2014-01-01

    Aliphatic polycarbonates were discovered a long time ago, with their conventional applications mostly limited to low molecular weight oligomeric intermediates for copolymerization with other polymers. Recent developments in polymerization techniques have overcome the difficulty in preparing high molecular weight aliphatic polycarbonates. These in turn, along with new functional monomers, have enabled the preparation of a wide range of aliphatic polycarbonates with diverse chemical compositions and structures. This review summarizes the latest polymerization techniques for preparing well-defined functional aliphatic polycarbonates, as well as the new applications of those aliphatic polycarbonates, esecially in the biomedical field. PMID:24994939

  5. Preparation and characterization of poly (arylene ether isoxazole)s by fluoride ion-mediated aromatic nucleophilic displacement reactions

    NASA Technical Reports Server (NTRS)

    Herbert, C. G.; Bass, R. G.

    1994-01-01

    As part of a continuing effort to prepare novel thermally stable high-performance polymers, poly(arylene ether isoxazole)s have been prepared by fluoride ion-catalyzed aromatic nucleophilic substitution reactions with bis(trimethylsiloxyphenyl) isoxazoles and activated bisarylhalides in diphenyl sulfone. Initial investigation involving the preparation of these materials with isoxazole bisphenols and activated bisarylhalides in the presence of potassium carbonate indicated that, under reaction conditions necessary to prepare high-molecular-weight materials, the isoxazole monomer was converted to an enamino ketone. This side reaction was avoided by using fluoride as a base. However, trimethylsilyl ether derivatives of the isoxazole bisphenols were required in these polymerizations for the preparation of high-molecular-weight materials. Moderate to high inherent viscosity eta(sub inh): 0.43-0.87 dl/g) materials with good thermal stability (air: 409-477 C, helium: 435-512 C) can be prepared by the silyl ether method. Glass transition temperatures ranged from 182 to 225 C for polymers with phenyl pendants and from 170 to 214 C for those without. Molecular weight control by 2% endcapping and the incorporation of a phenyl pendant at the 4 position of the isoxazole is necessary to yield polymers soluble in polar aprotic solvents at room temperature. There is evidence, however, indicating the existence of crosslinks between the polymer chains when the silyl ether approach is utilized.

  6. Metal-metal bonding and aromaticity in [M2(NHCHNH)3]2 (μ-E)2 (E = O, S; M = Nb, Mo, Tc, Ru, Rh).

    PubMed

    Yan, Xiuli; Meng, Lingpeng; Sun, Zheng; Li, Xiaoyan

    2016-02-01

    The nature of M-M bonding and aromaticity of [M2(NHCHNH)3]2(μ-E)2 (E = O, S; M = Nb, Mo, Tc, Ru, Rh) was investigated using atoms in molecules (AIM) theory, electron localization function (ELF), natural bond orbital (NBO) and molecular orbital analysis. These analyses led to the following main conclusions: in [M2(NHCHNH)3]2(μ-E)2 (E = O, S; M = Nb, Mo, Tc, Ru, Rh), the Nb-Nb, Ru-Ru, and Rh-Rh bonds belong to "metallic" bonds, whereas Mo-Mo and Tc-Tc drifted toward the "dative" side; all these bonds are partially covalent in character. The Nb-Nb, Mo-Mo, and Tc-Tc bonds are stronger than Ru-Ru and Rh-Rh bonds. The M-M bonds in [M2(NHCHNH)3]2(μ-S)2 are stronger than those in [M2(NHCHNH)3]2(μ-O)2 for M = Nb, Mo, Tc, and Ru. The NICS(1)ZZ values show that all of the studied molecules, except [Ru2(NHCHNH)3]2(μ-O)2, are aromaticity molecules. O-bridged compounds have more aromaticity than S-bridged compounds. Graphical Abstract Left Molecular graph, and right electron localization function (ELF) isosurface of [M2(NHCHNH)3]2(μ-E)2(E = O, S; M = Nb, Mo, Tc, Ru, Rh).

  7. Binding of aromatic amines to the rat hepatic Ah receptor in vitro and in vivo and the 8S and 4S estrogen receptor of rat uterus and rat liver

    SciTech Connect

    Cikryt, P.; Kaiser, T.; Gottlicher, M. )

    1990-08-01

    Studies on structurally related aromatic amines with different carcinogenic properties have shown that 2-acetylaminofluorene (2-AAF) and 2-acetylaminophenanthrene (AAP) inhibit the binding of 2,3,7,8-tetrachlorodibenzo-p-dioxin to the Ah receptor in vitro. The apparent inhibitor constants (K{sub i}) are 2.3 {mu}M for 2-AAF and 2.7 {mu}M for AAP. In contrast, 4-acetylaminofluorene, an isomer of 2-AAF, and trans-4-acetylaminostilbene do not bind to the rat hepatic cytosolic Ah receptor. Pretreating female Wistar rats with 2-AAF or AAP leads to the induction of the P-450 isoenzymes that are under the control of the Ah receptor. Ornithine decarboxylase activity is induced by all aromatic amines tested irrespective of their Ah receptor affinity. The aromatic amines used as model compounds do not inhibit the binding of 17-{beta}-estradiol to the 8S and 4S estrogen receptor of rat uterus or rat liver in a competition assay analyzed using sucrose density gradient centrifugation. On the other hand, the aromatic amines bind to varying extents to another estrogen-binding protein of rat liver whose function and identity is still unknown. The study demonstrates that structurally related aromatic amines in their unmetabolized form interact differentially with a cellular target protein, the Ah receptor, in vitro as well as in vivo. However, a relationship between these effects and the postulated promoting properties of 2-AAF remains to be established.

  8. New aliphatic glycerophosphoryl-containing polyurethanes: synthesis, platelet adhesion and elution cytotoxicity studies.

    PubMed

    Acetti, Daniela; D'Arrigo, Paola; Giordano, Carmen; Macchi, Piero; Servi, Stefano; Tessaro, Davide

    2009-04-01

    in this study new poly(ether)urethanes (PeUs) based on aliphatic diisocyanates were synthesized with phospholipid-like residues as chain extenders. The primary objective was to prepare new polyurethanes from diisocyanates that are less toxic than the aromatic ones widely used in medical-grade polyurethanes, in order to investigate the effect of the different aromatic or aliphatic hard segment content on the final properties of the materials. Some glycerophospho residues were simultaneously introduced to enhance the hemocompatibility of these materials. Polymers were prepared by a conventional two-step solution polymerization procedure using hexamethylene diisocyanate (HDi) and dodecametilendiisocyanate (DDi) and poly(1,4-butanediol) with molecular weight 1000 to form prepolymers, which were subsequently polymerized with 1-glycerophosphorylcholine (1-GPC) or glycerophosphorylserine (GPS) to act as chain extenders. The reference polymers bearing 1,4-butandiol (BD) were also synthesized. The polymers obtained were characterized by fourier transform infrared spectroscopy (fT-iR), nuclear magnetic resonance (1H nmR), and differential scanning calorimetry (DSC). The hemocompatibility of synthesized segmented polyurethanes was preliminarily investigated by platelet-rich plasma contact studies and related scanning electron microscopy (Sem) photographs as well as by cell viability assay after cell exposure to material elutions to assess the effect of any toxic leachables coming out from the samples. Two of the polymers gave interesting results, suggesting the desirability of further investigation into their possible use in biomedical devices.

  9. Aromatic graphene

    NASA Astrophysics Data System (ADS)

    Das, D. K.; Sahoo, S.

    2016-04-01

    In recent years graphene attracts the scientific and engineering communities due to its outstanding electronic, thermal, mechanical and optical properties and many potential applications. Recently, Popov et al. [1] have studied the properties of graphene and proved that it is aromatic but without fragrance. In this paper, we present a theory to prepare graphene with fragrance. This can be used as scented pencils, perfumes, room and car fresheners, cosmetics and many other useful household substances.

  10. Direct Functionalization of Poly(spirophosphazene)s via the Regioselective Lithiation of the Aromatic Rings Using a Cooperative Superbase.

    PubMed

    de la Campa, Raquel; García, Diego; Rodríguez, Sandra; Carriedo, Gabino A; Presa Soto, Alejandro

    2017-03-27

    The direct chemical functionalization of poly(spirophosphazene) [NP(O2 C12 H8 )]n (1) can be performed by the lithiation of the aromatic rings at low temperature using Schlosser's base (Li(t) Bu/KO(t) Bu or "superbase"), and the subsequent reaction with various electrophiles such as ClSiMe3 , ClPPh2 , or MeOB(O2 C6 H12 ) (MeOBpin). The functionalized polymers, isolated in very high yields (>90%) and without degradation of the polymeric chains, have an average degree of substitution per repeat unit ranging from 0.3 (random copolymers) to a maximum of 1.0, which corresponds to the homopolymers [NP(O2 C12 H7 FG)]n (FG (functional group) =SiMe3 , PPh2 , and Bpin). NMR studies, including bidimensional high temperature experiments on silylated and deuterated polymers, show that the substitution is regioselectively occurring at the C3 carbon of the aromatic rings due to the coordination of the lithium cations to the nitrogen of the polyphosphazene chain. The introduction of functional groups on the aromatic rings leads to significant changes in the solubility (silylated polymers), Tg , and electronic properties of the material, showing how the change of substituents in the aromatic rings can lead to polyphosphazenes with properties markedly different from those of the precursor polymer.

  11. Regulation of glutathione S-transferase Ya subunit gene expression: Identification of a unique xenobiotic-responsive element controlling inducible expression by planar aromatic compounds

    SciTech Connect

    Rushmore, T.H.; King, R.G.; Pickett, C.B. ); Paulson, K.E. )

    1990-05-01

    The authors have identified a region in the 5{prime} flanking sequence of the glutathione S-transferase Ya subunit gene that contains a unique xenobiotic-responsive element (XRE). The regulatory region spans nucleotides {minus}722 to {minus}682 of the 5{prime} flanking sequence and is responsible for part of the basal level as well as inducible expression of the Ya subunit gene by planar aromatic compounds such as {beta}-naphthoflavone ({beta}-NF) and 3-methylcholanthrene. The DNA sequence of this region ({beta}-NF-responsive element) is distinct from the DNA sequence of the XRE found in the cytochrome P-450 IA1 gene. In addition to the region containing the {beta}-NF-responsive element, two other regulatory regions of the Ya subunit gene have been identified. The data suggest that regulation of gene expression by planar aromatic compounds can be mediated by a DNA sequence this is distinct from the XRE sequence.

  12. Sources and distribution of aliphatic and polyaromatic hydrocarbons in coastal sediments from the Ushuaia Bay (Tierra del Fuego, Patagonia, Argentina).

    PubMed

    Commendatore, Marta G; Nievas, Marina L; Amin, Oscar; Esteves, José L

    2012-03-01

    The environmental quality of Ushuaia Bay, located at the southernmost tip of South America, is affected by the anthropogenic pressure of Ushuaia city. In this study, levels and sources of hydrocarbons in coastal sediments were assessed. Aliphatic hydrocarbon fractions ranged between 5.5 and 1185.3 μg/g dry weight and PAHs from not detected to 360 ng/g. Aliphatic diagnostic indices, the nalkanes homologous series occurrence, Aliphatic Unresolved Complex Mixtures (AliUCMs), and pristane and phytane isoprenoids indicated a petrogenic input. Some sites showed biogenic features masked by the anthropogenic signature. Particularly in port areas biodegradation processes were evident. PAH ratios showed a mixture of petrogenic and pyrogenic sources. Aliphatic and aromatic UCMs were strongly correlated, reflecting chronic pollution. Three areas were distinguished inside the bay: (1) east, with low hydrocarbons impact; (2) central, where hydrocarbons accumulation was related to source proximity and sediment characteristics; (3) south-west, where sediment characteristics and current circulation favour hydrocarbons accumulation.

  13. NMR determination of carbon aromatization during hydrous pyrolysis of coals from the Mesaverde group, Greater Green river basin

    SciTech Connect

    Miknis, F.P.; Netzel, D.A.; Surdam, R.C.

    1995-12-01

    Solid-state {sup 13}C NMR measurements have been made on the residues from hydrous pyrolysis experiments conducted on Almond and Lance Formation coals from the Upper Cretaceous Mesaverde Group in the Green River Basin. Only a small percentage of the total carbon (13%) was converted to volatile products for both coals during hydrous pyrolysis. An accounting of the aliphatic carbon was obtained by comparing the aliphatic carbon in the gas, oil and residue products with that of the starting coals. The amount of aliphatic carbon in the volatile products and residue was not sufficient to account for the total amount of aliphatic carbon that disappeared. From this it was inferred that a substantial portion of the aliphatic carbon aromatized during hydrous pyrolysis, (48 and 56% for the Almond and Lance coal, respectively). These and additional results on coal maturation in the natural environment will be discussed.

  14. Spreading coefficients of aliphatic hydrocarbons on water

    SciTech Connect

    Takii, Taichi; Mori, Y.H. . Dept. of Mechanical Engineering)

    1993-11-01

    Experiments have been performed to determine the equilibrium spreading coefficients of some aliphatic hydrocarbons (C[sub 6]C[sub 10]) on water. The thickness of a discrete lens of each hydrocarbon sample floating on a stagnant water pool was measured interferometrically and used to calculate the spreading coefficient of the hydrocarbon with the aid of Langmuir's capillarity theory. The dependences of the spreading coefficient, thus observed, on temperature (0--50 C) and on the number of carbon atoms in the hydrocarbon molecule are in qualitative agreement with the predictions based on the Lifshitz theory of van der Waals forces.

  15. Aliphatic hydrocarbons of the Murchison meteorite

    NASA Technical Reports Server (NTRS)

    Cronin, John R.; Pizzarello, Sandra

    1990-01-01

    Hydrocarbon fractions from the Murchison meteorite were prepared using benzene-methanol as the extraction solvent, fractionated on silica gel columns, and analyzed using gas chromatography combined with mass spectrometry and IR and NMR techniques. Results indicate that the most abundant aliphatic hydrocarbon components of the Murchison meteorite are C15 to C30 branched-alkyl-substituted mono-, di-, and tricyclic alkanes. It is shown that the n-alkanes, methyl alkanes, and isoprenoid alkanes that are sometimes found in extracts of the Murchison meteorite are terrestrial contaminants.

  16. Structural Basis of Substrate Conversion in a New Aromatic Peroxygenase

    PubMed Central

    Piontek, Klaus; Strittmatter, Eric; Ullrich, René; Gröbe, Glenn; Pecyna, Marek J.; Kluge, Martin; Scheibner, Katrin; Hofrichter, Martin; Plattner, Dietmar A.

    2013-01-01

    Aromatic peroxygenases (APOs) represent a unique oxidoreductase sub-subclass of heme proteins with peroxygenase and peroxidase activity and were thus recently assigned a distinct EC classification (EC 1.11.2.1). They catalyze, inter alia, oxyfunctionalization reactions of aromatic and aliphatic hydrocarbons with remarkable regio- and stereoselectivities. When compared with cytochrome P450, APOs appear to be the choice enzymes for oxyfunctionalizations in organic synthesis due to their independence from a cellular environment and their greater chemical versatility. Here, the first two crystal structures of a heavily glycosylated fungal aromatic peroxygenase (AaeAPO) are described. They reveal different pH-dependent ligand binding modes. We model the fitting of various substrates in AaeAPO, illustrating the way the enzyme oxygenates polycyclic aromatic hydrocarbons. Spatial restrictions by a phenylalanine pentad in the active-site environment govern substrate specificity in AaeAPO. PMID:24126915

  17. Polybenzoxazole via aromatic nucleophilic displacement

    NASA Technical Reports Server (NTRS)

    Hergenrother, Paul M. (Inventor); Connell, John W. (Inventor); Smith, Joseph G., Jr. (Inventor)

    1993-01-01

    Polybenzoxazoles (PBO) are heterocyclic macromolecules which were first synthesized in a two-step process by the initial formation of aromatic diacid chlorides with bis(o-aminophenol)s through solution condensation of aromatic diacid chlorides with bis(o-aminophenol)s followed by thermal cyclodehydration. Since then several methods were utilized in their synthesis. The most common synthetic method for PBO involves a polycondensation of bis(o-aminophenol)s with aromatic diacid diphenyl esters. Another preparative route involves the solution polycondensation of the hydrochloride salts of bis(o-amino phenol)s with aromatic diacids in polyphosphoric acid. Another synthetic method involves the initial formation of poly(o-hydroxy amide)s from silylated bis(o-aminophenol)s with aromatic diacid chlorides followed by thermal cyclodehydration to PBO. A recent preparative route involves the reaction of aromatic bisphenols with bis(fluorophenyl) benzoxazoles by the displacement reaction to form PBO. The novelty of the present invention is that high molecular weight PBO of new chemical structures are prepared that exhibit a favorable combination of physical and mechanical properties.

  18. Structurally simple pyridine N-oxides as efficient organocatalysts for the enantioselective allylation of aromatic aldehydes.

    PubMed

    Pignataro, Luca; Benaglia, Maurizio; Annunziata, Rita; Cinquini, Mauro; Cozzi, Franco

    2006-02-17

    A series of structurally simple pyridine N-oxides have readily been assembled from inexpensive amino acids and tested as organocatalysts in the allylation of aldehydes with allyl(trichloro)silane to afford homoallylic alcohols. (S)-proline-based catalysts afforded the products derived from aromatic aldehydes in fair to good yields and in up to 84% enantiomeric excess (ee). The allylation of heteroaromatic, unsaturated, and aliphatic aldehydes was less satisfactory. By running the reaction in the presence of achiral and chiral additives and structurally different catalysts, we collected some insights into the relationship between the stereochemical outcome and the catalyst's structural features. Even if the ee's obtained are inferior to the best values observed with other catalysts, this work concurs to show that structurally simple pyridine N-oxides can also promote the allylation reaction with satisfactory stereocontrol.

  19. Photoelectron spectroscopy of s-triazine anion clusters: Polarization-induced electron binding in aza-aromatic molecule

    NASA Astrophysics Data System (ADS)

    Kim, Jeong Hyun; Song, Jae Kyu; Park, Hyokeun; Lee, Sang Hak; Han, Sang Yun; Kim, Seong Keun

    2003-08-01

    Photoelectron spectroscopy was carried out for the mass-selected cluster anions of s-triazine molecule, Tzn- (n=1-6). The mass spectrum and vibrationally resolved photoelectron spectrum of Tz- showed that unlike pyridine and pyrazine, Tz binds an electron and thus becomes the first molecule in the azabenzene series with a positive electron affinity (0.03 eV). This indicates that the local charge polarization in the aromatic ring by the three nitrogen atoms is large enough to facilitate electron binding to a homologue of benzene. A Jahn-Teller distortion was proposed to explain the vibrational progressions of the photoelectron spectrum of Tz-. A series of Ar-solvated clusters of Tz-, Tz-ṡArm (m=1-7), have been also studied. Their photoelectron spectra showed a drop in the incremental electron binding energy when going from m=4 to 5, indicating the closure of a solvation shell with four Ar atoms. In the mass abundance spectrum of Tzn-, a distinctly high intensity for Tz2- indicated its exceptional stability, which was also manifested by the large increase by more than 0.5 eV in the vertical detachment energy of the photoelectron spectrum. Theoretical calculations were carried out to obtain optimized geometries of the neutral and anion of Tz and Tz2. We confirmed the Jahn-Teller distortion in Tz- and also addressed the role of hydrogen bonding in determining the geometries of Tz2-. A common feature for the two most stable forms of Tz2- with comparable energies was that they achieve their unique stability through equal sharing of the negative charge between their two molecular constituents. A new photoelectron band was found to emerge from Tzn- for n⩾2 by the 355 nm light, in addition to the photoelectron band at lower electron binding energy observed for n⩾1 at 532 nm. The relative intensity of this new band decreased as n increased, and its position was 1.6-1.8 eV above the first band. Photodetachment to an electronically excited state was suggested to give

  20. Synthesis of aromatic secondary diamines

    NASA Technical Reports Server (NTRS)

    Wolfe, J. F.; Greenwood, T. D.; Kahley, R. A.

    1979-01-01

    A series of N-methyl substituted aromatic polyamides derived from the secondary aromatic diamines, 4,4'-bis(methylamino)diphenylmethane, 3,3'-bis(methylamino) diphenylmethane, 4,4'-bis(methylamino)benzophenone or 3,3'-bis(methylamino)benzophenone and isophthaloyl dichloride, terphthaloyl dichloride or 3,3'diphenylmethane dicarboxylic acid dichloride was prepared by high temperature solution polymerization in s-tetrachloroethane. Compared to analogous unsubstituted and partially N-methylated aromatic polyamides, the full N-methylated polyamides exhibited significantly lower glass transition temperatures, reduced crystallinity, improved thermal stability and good solubility in chlorinated solvents.

  1. OLFACTORY RESPONSES OF BLOWFLIES TO ALIPHATIC ALDEHYDES

    PubMed Central

    Dethier, V. G.

    1954-01-01

    The response of the blowfly Phormia regina to stimulation by aldehydes in the vapor phase has been studied by means of a specially designed olfactometer. The median rejection threshold and the maximum acceptance threshold were selected as criteria of response. For both acceptance and rejection the distribution of thresholds in the population is normal with respect to the logarithm of concentration. When thresholds are expressed as molar concentrations, the values decrease progressively as chain length is increased. There is no attraction beyond decanal and no rejection beyond dodecanal. When thresholds are expressed as activities, most members of the aldehyde series are approximately equally stimulating at rejection and equally stimulating at acceptance. The relationship is most exact over the middle range of chain lengths. There is a tendency for the terminal members to stimulate at higher activities. These relationships are in close agreement with those which were found earlier to apply to the normal aliphatic alcohols. The similarity between the relative actions of the members of the two series suggests that the relation of equal olfactory stimulation at equal thermodynamic activities by homologous aliphatic compounds at least for homologues of intermediate chain length may be of rather general application in olfaction. PMID:13174780

  2. 40 CFR 721.2270 - Aliphatic dicarboxylic acid salt.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Aliphatic dicarboxylic acid salt. 721... Substances § 721.2270 Aliphatic dicarboxylic acid salt. (a) Chemical substance and significant new uses... salt (PMN P-92-1352) is subject to reporting under this section for the significant new uses...

  3. Isolation and characterization of different bacterial strains for bioremediation of n-alkanes and polycyclic aromatic hydrocarbons.

    PubMed

    Guermouche M'rassi, A; Bensalah, F; Gury, J; Duran, R

    2015-10-01

    Crude oil is a common environmental pollutant composed of a large number of both aromatic and aliphatic hydrocarbons. Biodegradation is carried out by microbial communities that are important in determining the fate of pollutants in the environment. The intrinsic biodegradability of the hydrocarbons and the distribution in the environment of competent degrading microorganisms are crucial information for the implementation of bioremediation processes. In the present study, the biodegradation capacities of various bacteria toward aliphatic and aromatic hydrocarbons were determined. The purpose of the study was to isolate and characterize hydrocarbon-degrading bacteria from contaminated soil of a refinery in Arzew, Algeria. A collection of 150 bacterial strains was obtained; the bacterial isolates were identified by 16S rRNA gene sequencing and their ability to degrade hydrocarbon compounds characterized. The isolated strains were mainly affiliated to the Gamma-Proteobacteria class. Among them, Pseudomonas spp. had the ability to metabolize high molecular weight hydrocarbon compounds such as pristane (C19) at 35.11 % by strain LGM22 and benzo[a] pyrene (C20) at 33.93 % by strain LGM11. Some strains were able to grow on all the hydrocarbons tested including octadecane, squalene, phenanthrene, and pyrene. Some strains were specialized degrading only few substrates. In contrast, the strain LGM2 designated as Pseudomonas sp. was found able to degrade both linear and branched alkanes as well as low and high poly-aromatic hydrocarbons (PAHs). The alkB gene involved in alkane degradation was detected in LGM2 and other Pseudomonas-related isolates. The capabilities of the isolated bacterial strains to degrade alkanes and PAHs should be of great practical significance in bioremediation of oil-contaminated environments.

  4. Microbial production of the aromatic building-blocks (S)-styrene oxide and (R)-1,2-phenylethanediol from renewable resources.

    PubMed

    McKenna, Rebekah; Pugh, Shawn; Thompson, Brian; Nielsen, David R

    2013-12-01

    (S)-Styrene oxide and (R)-1,2-phenylethanediol are chiral aromatic molecular building blocks used commonly as precursors to pharmaceuticals and other specialty chemicals. Two pathways have been engineered in Escherichia coli for their individual biosynthesis directly from glucose. The novel pathways each constitute extensions of the previously engineered styrene pathway, developed by co-expressing either styrene monooxygenase (SMO) or styrene dioxygenase (SDO) to convert styrene to (S)-styrene oxide and (R)-1,2-phenylethanediol, respectively. StyAB from Pseudomonas putida S12 was determined to be the most effective SMO. SDO activity was achieved using NahAaAbAcAd of Pseudomonas sp. NCIB 9816-4, a naphthalene dioxygenase with known broad substrate specificity. Production of phenylalanine, the precursor to both pathways, was systematically enhanced through a number of mutations, most notably via deletion of tyrA and over-expression of tktA. As a result, (R)-1,2-phenylethanediol reached titers as high as 1.23 g/L, and at 1.32 g/L (S)-styrene oxide titers already approach their toxicity limit. As with other aromatics, product toxicity was strongly correlated with a model of membrane accumulation and disruption. This study additionally demonstrates that greater flux through the styrene pathway can be achieved if its toxicity is addressed, as achieved in this case by reacting styrene to less toxic products.

  5. Reduction of Aromatic Hydrocarbons by Zero-Valent Iron and Palladium Catalyst

    SciTech Connect

    Kim, Young-Hun; Shin, Won Sik; Ko, Seok-Oh; Kim, Myung-Chul

    2004-03-31

    Permeable reactive barrier (PRB) is an alternative technology for soil and groundwater remediation. Zero valent iron, which is the most popular PRB material, is only applicable to halogenated aliphatic organics and some heavy metals. The objective of this study was to investigate reductive dechlorination of halogenated compounds and reduction of non-halogenated aromatic hydrocarbons using zero valent metals (ZVMs) and catalysts as reactive materials for PRBs. A group of small aromatic hydrocarbons such as monochlorophenols, phenol and benzene were readily reduced with palladium catalyst and zero valent iron. Poly-aromatic hydrocarbons (PAHs) were also tested with the catalysts and zero valent metal combinations. The aromatic rings were reduced and partly reduced PAHs were found as the daughter compounds. The current study demonstrates reduction of aromatic compounds by ZVMs and modified catalysts and implicates that PRB is applicable not only for halogenated organic compounds but nonhalogenated aromatic compounds such as PAHs.

  6. Validation of Alternatives to Aliphatic Isocyanate Polyurethanes

    NASA Technical Reports Server (NTRS)

    Curran, Jerome

    2007-01-01

    The National Aeronautics and Space Administration (NASA) Headquarters chartered the Acquisition Pollution Prevention (AP2) Office to coordinate agency activities affecting pollution prevention issues identified during system and component acquisition and sustainment processes. The primary objective of this effort is to demonstrate and validate alternatives to aliphatic isocyanate polyurethane coatings. Successful completion of this project will result in one or more isocyanate-free coating systems qualified for use at Air Force Space Command (AFSPC) and NASA centers participating in this study. The objective of this project is to qualify the candidates under the specifications for the standard system. This project will compare coating performance of the proposed alternatives to existing coating systems or standards.

  7. Synthesis and characterization of thermally stable aromatic polyamides and poly(1,3,4-oxadiazole-amide)s nanoparticles containing pendant substituted bezamides

    PubMed Central

    2013-01-01

    Background The introduction of pendent bulky groups along the polymer backbone results in a less ordered polymer matrix and increases the solubility characteristics without affecting thermal properties. The inclusion of chromogenic chemical moieties in the chains can give rise to the luminescent converter material which permits the preparation of materials with potential applications. Aromatic polymers containing heterocyclic rings in the main chain are known for their high thermal resistance, good hydrolytic stability, low dielectric and tough mechanical properties. There is currently much research directed towards the discovery of new blue light-emitting polymers, with characteristics of high efficiency and high reliability. Herein, we describe the preparation of aromatic polyamides and poly (1,3,4-oxadiazole-amide)s nanoparticles with pendant structures comprised of m- and p-acetoxybenzamide groups, where the acetoxybenzamide groups act as signaling units due to their fluorescent and chromogenic characteristics. Results Aromatic polyamides and poly(1,3,4-oxadiazole-amide)s nanoparticles with pendant structures comprised of m- and p-acetoxybenzamide groups were successfully prepared and characterized using different analytical methods. Most polyamides were obtained as well-separated spherical nanoparticles while aramide containing pyridine produced aggregated particles attributed to the molecular self assembly via H-bond directed organization of molecular precursors. The thermal behavior of all polymers exhibited two major thermal decompositions due to the subsequent breakage of the acetoxy group in the lateral chain and cleavage of the main amide bonds. Photoluminescence studies revealed that the blue emissions for the polyamide derived from benzidine were blue-shifted (shifted to a lower wavelength) compared to that of polyamides containing flexible linkages. Conclusions We report the synthesis of aromatic polyamides and poly(1,3,4-oxadiazole-amide)s

  8. Polybenzimidazoles via aromatic nucleophilic displacement

    NASA Technical Reports Server (NTRS)

    Connell, John W. (Inventor); Hergenrother, Paul M. (Inventor); Smith, Joseph G., Jr. (Inventor)

    1995-01-01

    Novel molecular weight controlled and endcapped polybenzimidazoles (PBI) are prepared by the aromatic nucleophilic displacement reaction of di(hydroxyphenyl benzimidazole) monomers with activated aromatic dihalides or activated aromatic dinitro compounds. The PBI are endcapped with mono(hydroxyphenyl) benzimidazoles. The polymerizations are carried out in polar aprotic solvents such as N-methyl-2-pyrrolidinone or N,N-dimethylacetamide using alkali metal bases such as potassium carbonate at elevated temperatures under nitrogen. Mono(hydroxyphenyl) benzimidazoles are synthesizedby reacting phenyl-4-hydroxybenzoate with aromatic (o-diamine)s in diphenylsulfone. Molecular weight controlled and endcapped PBI of new chemical structures are prepared that exhibit a favorable combination of physical and mechanical properties.

  9. Polybenzimidazoles Via Aromatic Nucleophilic Displacement

    NASA Technical Reports Server (NTRS)

    Connell, John W. (Inventor); Hergerrother, Paul M. (Inventor); Smith, Joseph G., Jr. (Inventor)

    1997-01-01

    Novel molecular weight controlled and endcapped polybenzimidazoles (PBI) are prepared by the aromatic nucleophilic displacement reaction of di(hydroxyphenylbenzimidazole) monomers with activated aromatic dihalides or activated aromatic dinitro compounds. The PBI are endcapped with mono(hydroxyphenyl)benzimidazoles. The polymerizations are carried out in polar aprotic solvents such as N-methyl-2-pyrrolidinone or N,N-dimethylacetamide using alkali metal bases such as potassium carbonate at elevated temperatures under nitrogen. Mono(hydroxyphenyl)benzimidazoles are synthesized by reacting phenyl-4-hydroxybenzoate with aromatic (o-diamine)s in diphenylsulfone. Molecular weight controlled and endcapped PBI of new chemical structures are prepared that exhibit a favorable combination of physical and mechanical properties.

  10. Direct production of hydrogen and aromatics from methane or natural gas: Review of recent U.S. patents

    SciTech Connect

    Lucia M. Petkovic; Daniel M. Ginosar

    2012-03-01

    Since the year 2000, the United States Patent and Trademark Office (USPTO) has granted a dozen patents for inventions related to methane dehydroaromatization processes. One of them was granted to UOP LLC (Des Plaines). It relates to a catalyst composition and preparation method. Two patents were granted to Conoco Phillips Company (Houston, TX). One was aimed at securing a process and operating conditions for methane aromatization. The other was aimed at securing a process that may be integrated with separation of wellhead fluids and blending of the aromatics produced from the gas with the crude. Nine patents were granted to ExxonMobil Chemical Patents Inc. (Houston, TX). Most of these were aimed at securing a dehydroaromatization process where methane-containing feedstock moves counter currently to a particulate catalyst. The coked catalyst is heated or regenerated either in the reactor, by cyclic operation, or in annex equipment, and returned to the reactor. The reactor effluent stream may be separated in its main components and used or recycled as needed. A brief summary of those inventions is presented in this review.

  11. Reflectance spectroscopy (350-2500 nm) of solid-state polycyclic aromatic hydrocarbons (PAHs)

    NASA Astrophysics Data System (ADS)

    Izawa, M. R. M.; Applin, D. M.; Norman, L.; Cloutis, E. A.

    2014-07-01

    Polycyclic aromatic hydrocarbons (PAHs) are organic compounds based on fused aromatic rings, and are formed in a variety of astrophysical, solar nebula and planetary processes. Polycyclic aromatic hydrocarbons are known or suspected to occur in a wide variety of planetary settings including icy satellites, Titan’s hazes, carbonaceous meteorites, comet nuclei, ring particles; and terrestrial organic-rich lithologies such as coals, asphaltites, and bituminous sands. Relatively few measurements of the visible and near-infrared spectra of PAHs exist, yet this wavelength region (350-2500 nm) is widely used for remote sensing. This study presents detailed analyses of the 350-2500 nm reflectance spectra of 47 fine-grained powders of different high-purity solid-state PAHs. Spectral properties of PAHs change with variations in the number and connectivity of linked aromatic rings and the presence and type of side-groups and heterocycles. PAH spectra are characterized by three strong features near ∼880 nm, ∼1145 nm, and ∼1687 nm due to overtones of νCH fundamental stretching vibrations. Some PAHs are amenable to remote detection due to the presence of diagnostic spectral features, including: Nsbnd H stretching overtones at 1490-1515 nm in NH- and NH2-bearing PAHs, aliphatic or saturated bond Csbnd H overtone vibrations at ∼1180-1280 nm and ∼1700-1860 nm; a broad asymmetric feature between ∼1450 nm and ∼1900 nm due to Osbnd H stretching overtones in aromatic alcohols, Csbnd H and Cdbnd O combinations near ∼2000-2010 nm and ∼2060-2270 nm in acetyl and carboxyl-bearing PAHs. Other substituents such as sulphonyl, thioether ether and carboxyl heterocycles, or cyano, nitrate, and aromatic side groups, do not produce well-resolved diagnostic spectral features but do cause shifts in the positions of the aromatic Csbnd H vibrational overtone features. Fluorescence is commonly suppressed by the presence of heterocycles, side-groups and in many non-alternant PAHs

  12. Role of Intramolecular Aromatic π-π Interactions in the Self-Assembly of Di-l-Phenylalanine Dipeptide Driven by Intermolecular Interactions: Effect of Alanine Substitution.

    PubMed

    Reddy, Samala Murali Mohan; Shanmugam, Ganesh

    2016-09-19

    Although the role of intermolecular aromatic π-π interactions in the self-assembly of di-l-phenylalanine (l-Phe-l-Phe, FF), a peptide that is known for hierarchical structure, is well established, the influence of intramolecular π-π interactions on the morphology of the self-assembled structure of FF has not been studied. Herein, the role of intramolecular aromatic π-π interactions is investigated for FF and analogous alanine (Ala)-containing dipeptides, namely, l-Phe-l-Ala (FA) and l-Ala-l-Phe (AF). The results reveal that these dipeptides not only form self-assemblies, but also exhibit remarkable differences in structural morphology. The morphological differences between FF and the analogues indicate the importance of intramolecular π-π interactions, and the structural difference between FA and AF demonstrates the crucial role of the nature of intramolecular side-chain interactions (aromatic-aliphatic or aliphatic-aromatic), in addition to intermolecular interactions, in deciding the final morphology of the self-assembled structure. The current results emphasise that intramolecular aromatic π-π interaction may not be essential to induce self-assembly in smaller peptides, and π (aromatic)-alkyl or alkyl-π (aromatic) interactions may be sufficient. This work also illustrates the versatility of aromatic and a combination of aromatic and aliphatic residues in dipeptides in the formation of structurally diverse self-assembled structures.

  13. Palladium-catalyzed hydroaminocarbonylation of alkenes with amines: a strategy to overcome the basicity barrier imparted by aliphatic amines.

    PubMed

    Zhang, Guoying; Gao, Bao; Huang, Hanmin

    2015-06-22

    A novel and efficient palladium-catalyzed hydroaminocarbonylation of alkenes with aminals has been developed under mild reaction conditions, and allows the synthesis of a wide range of N-alkyl linear amides in good yields with high regioselectivity. On the basis of this method, a cooperative catalytic system operating by the synergistic combination of palladium, paraformaldehyde, and acid was established for promoting the hydroaminocarbonylation of alkenes with both aromatic and aliphatic amines, which do not react well under conventional palladium-catalyzed hydroaminocarbonylation.

  14. Biodegradation of individual and multiple chlorinated aliphatic hydrocarbons by methane-oxidizing cultures.

    PubMed Central

    Chang, H L; Alvarez-Cohen, L

    1996-01-01

    The microbial degradation of chlorinated and nonchlorinated methanes, ethanes, and ethanes by a mixed methane-oxidizing culture grown under chemostat and batch conditions is evaluated and compared with that by two pure methanotrophic strains: CAC1 (isolated from the mixed culture) and Methylosinus trichosporium OB3b. With the exception of 1,1-dichloroethylene, the transformation capacity (Tc) for each chlorinated aliphatic hydrocarbon was generally found to be in inverse proportion to its chlorine content within each aliphatic group (i.e., methanes, ethanes, and ethenes), whereas similar trends were not observed for degradation rate constants. Tc trends were similar for all methane-oxidizing cultures tested. None of the cultures were able to degrade the fully chlorinated aliphatics such as perchloroethylene and carbon tetrachloride. Of the four cultures tested, the chemostat-grown mixed culture exhibited the highest Tc for trichloroethylene, cis-1,2-dichloroethylene, tetrachloroethane, 1,1,1-trichloroethane, and 1,2-dichloroethane, whereas the pure batch-grown OB3b culture exhibited the highest Tc for all other compounds tested. The product toxicity of chlorinated aliphatic hydrocarbons in a mixture containing multiple compounds was cumulative and predictable when using parameters measured from the degradation of individual compounds. The Tc for each chlorinated aliphatic hydrocarbon in a mixture (Tcmix) and the total Tc for the mixture (sigma Tcmix) are functions of the individual Tc, the initial substrate concentration (S0), and the first-order rate constant (k/Ks) of each compound in the mixture, indicating the importance of identifying the properties and compositions of all potentially degradable compounds in a contaminant mixture. PMID:8795228

  15. Adsorption of halogenated aliphatic contaminants by graphene nanomaterials.

    PubMed

    Zhou, Yang; Apul, Onur Guven; Karanfil, Tanju

    2015-08-01

    In this study, adsorption of ten environmentally halogenated aliphatic synthetic organic compounds (SOCs) by a pristine graphene nanosheet (GNS) and a reduced graphene oxide (rGO) was examined, and their adsorption behaviors were compared with those of a single-walled carbon nanotube (SWCNT) and a granular activated carbon (GAC). In addition, the impacts of background water components (i.e., natural organic matter (NOM), ionic strength (IS) and pH) on the SOC adsorption behavior were investigated. The results indicated HD3000 and SWCNT with higher microporous volumes exhibited higher adsorption capacities for the selected aliphatic SOCs than graphenes, demonstrating microporosity of carbonaceous adsorbents played an important role in the adsorption. Analysis of adsorption isotherms demonstrated that hydrophobic interactions were the dominant contributor to the adsorption of aliphatic SOCs by graphenes. However, π-π electron donor-acceptor and van der Waals interactions are likely the additional mechanisms contributing to the adsorption of aliphatic SOCs on graphenes. Among the three background solution components examined, NOM showed the most influential effect on adsorption of the selected aliphatic SOCs, while pH and ionic strength had a negligible effects. The NOM competition on aliphatic adsorption was less pronounced on graphenes than SWCNT. Overall, in terms of adsorption capacities, graphenes tested in this study did not exhibit a major advantage over SWCNT and GAC for the adsorption of aliphatic SOCs.

  16. Synthesis of aliphatic sulfur pentafluorides by oxidation of SF₅-containing anisole, phenols, and anilines.

    PubMed

    Vida, Norbert; Pastýříková, Tereza; Klepetářová, Blanka; Beier, Petr

    2014-09-19

    4-(Pentafluorosulfanyl)catechol, 2-amino-4-(pentafluorosulfanyl)phenol, and 2-amino-5-(pentafluorosulfanyl)phenol undergo oxidation by lead tetraacetate at ambient temperature leading to dearomatization and the formation of SF5-substituted nitriles and esters of cis,cis-hexa-2,4-dienedioic (muconic) acid in good yields. 4-(Pentafluorosulfanyl)phenol and 4-(pentafluorosulfanyl)anisole are oxidized by 30% aqueous hydrogen peroxide in concentrated sulfuric acid to provide 2-(5-oxo-3-(pentafluorosulfanyl)-2,5-dihydrofuran-2-yl)acetic acid [3-(pentafluorosulfanyl)muconolactone] and small amounts of side products--SF5-containing maleic and succinic acids. The methods presented are the first examples of the practical synthesis of aliphatic SF5-containing compounds from readily available aromatic ones.

  17. Catalytic trimerization of aromatic nitriles and triaryl-s-triazine ring cross-linked high temperature resistant polymers and copolymers made thereby

    NASA Technical Reports Server (NTRS)

    Hsu, L. C. (Inventor)

    1979-01-01

    Triazine compounds and cross-linked polymer compositions are made by heating aromatic nitriles to a temperature in the range of from about 100 C to about 700 C, and preferably in the range of from about 200 C to about 350 C, in the presence of a catalyst or mixture of catalysts selected from one or more of the following groups: (1) organic sulfonic and sulfinic acids, (2) organic phosphonic and phosphinic acids, and (3)metallic acetylacetonates, at a pressure in the range of from about atmospheric pressure to about 10,000 psi and preferably in the range of from about 200 psi to about 750 psi. Aromatic nitrile-modified (terminated and/or appended) imide, benzimidazole, imidazopyrrolone, quinoxaline, and other condensation type prepolymers or their precopolymers are made which are trimerized with or without a filler by the aforementioned catalytic trimerization process into triaryl-s-triazine ring containing or cross-linked polymeric or copolymeric products useful in applications requiring high thermal-oxidative stability and high performance structural properties at elevated temperatures.

  18. Segregation and Alteration of Phenolic and Aliphatic Components of Root and Leaf Litter by Detritivores and Microbes

    NASA Astrophysics Data System (ADS)

    Filley, T. R.; Altmann, J.; Szlavecz, K. A.; Kalbitz, K.; Gamblin, D.; Nierop, K.

    2012-12-01

    The physical and microbial transformation of plant detritus in the litter layer and soil is accompanied by chemical separation of progressively soluble fractions and their movement into the rhizosphere driving subsequent soil processes. We investigated the combined action of specific detritivores, microbial decay, and leaching on the chemical separation of plant aromatic and aliphatic components from root, wood, and leaf tissue using 13C-TMAH thermochemolysis. This method enabled the simultaneous analysis of hydrolyzable tannin and lignin fragments, substituted fatty acids, and condensed tannin composition and revealed process-specific chemical transformations to plant secondary compounds. Long-term incubation and field sampling demonstrated how plant residues are progressively leached of the water soluble, oxidized fragments generated through decay. The residues appeared only slightly altered, in the case of brown rot wood, or enriched in aliphatic fragments, in the case of leaf and root tissue. Water extractable fractions were always selectively dominated by polyphenolics, either as demethylated lignin or tannins, and nearly devoid of aliphatic materials, despite high concentrations in the starting materials. Additionally, for plant materials with high tannin contents, such as pine needles, consumption and passage through some arthropod guts revealed what appeared to be microbially-mediated methylation of phenols, and a loss of tannins in leachates. These findings are indications for an in-situ phenol detoxification mechanism. This research provides important information regarding the links between biochemical decay and the chemical nature of organic matter removed and remaining in the soil profile.

  19. ANAEROBIC AND AEROBIC TREATMENT OF CHLORINATED ALIPHATIC COMPOUNDS

    EPA Science Inventory

    Biological degradation of 12 chlorinated aliphatic compounds (CACs) was assessed in bench-top reactors and in serum bottle tests. Three continuously mixed daily batch-fed reactor systems were evaluated: anaerobic, aerobic, and sequential-anaerobic-aerobic (sequential). Glucose,...

  20. Silver-Catalyzed Decarboxylative Bromination of Aliphatic Carboxylic Acids.

    PubMed

    Tan, Xinqiang; Song, Tao; Wang, Zhentao; Chen, He; Cui, Lei; Li, Chaozhong

    2017-03-13

    The silver-catalyzed Hunsdiecker bromination of aliphatic carboxylic acids is described. With Ag(Phen)2OTf as the catalyst and dibromoisocyanuric acid as the brominating agent, various aliphatic carboxylic acids underwent decarboxylative bromination to provide the corresponding alkyl bromides under mild conditions. This method not only is efficient and general but also enjoys wide functional group compatibility. An oxidative radical mechanism involving Ag(II) intermediates is proposed.

  1. Process for producing peracids from aliphatic hydroxy carboxylic acids

    DOEpatents

    Chum, H.L.; Palasz, P.D.; Ratcliff, M.A.

    1984-12-20

    A process is described for producing peracids from lactic acid-containing solutions derived from biomass processing systems. It consists of adjusting the pH of the solution to about 8 to 9 and removing alkaline residue fractions therefrom to form a solution comprised substantially of lower aliphatic hydroxy acids. The solution is oxidized to produce volatile lower aliphatic aldehydes. The aldehydes are removed as they are generated and converted to peracids.

  2. Process for producing peracids from aliphatic hydroxy carboxylic acids

    DOEpatents

    Chum, Helena L.; Ratcliff, Matthew A.; Palasz, Peter D.

    1986-01-01

    A process for producing peracids from lactic acid-containing solutions derived from biomass processing systems comprising: adjusting the pH of the solution to about 8-9 and removing alkaline residue fractions therefrom to form a solution comprised substantially of lower aliphatic hydroxy acids; oxidizing the solution to produce volatile lower aliphatic aldehydes; removing said aldehydes as they are generated; and converting said aldehydes to peracids.

  3. Self-Assembled Templates of Aromatic Pentapeptides for Synthesis of CdS Quantum-Dots to Detect the Trace Amounts of Hg(2+) in Aqueous Solutions.

    PubMed

    Meng, Min; Dou, Yingying; Xu, Wenlong; Hao, Jingcheng

    2016-05-01

    Molecular self-assembly has become a popular tool to prepare nanomaterials with potential applications, such as ion-responsive detection of Hg(2+) in aqueous solutions. In this study, FFACD aromatic pentapeptides, whose N-terminuses were protected by carboxyl (Ac-FFACD) or a 9-fluorenylmethoxycarbonyl group (Fmoc-FFACD), were chosen as building blocks to produce nanostructures in solutions. Based on the preliminary determination of the critical aggregation concentration (CAC) of Ac-FFACD and Fmoc-FFACD aromatic pentapeptides in water, the order of magnitude of which is 10(-5) mol·L(-1), self-assembled spiral and networked nanowires can be easily obtained over a range of concentrations. These nanowires were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), and atomic force microscopy (AFM). The self-assembled spiral and networked nanowires were designed to be used as templates for preparing CdS quantum dots (QDs) in-situ at room temperature. The peptide-functionalized, nanowire-encapsulated CdS QDs can be used for rapid, sensitive, and selective detection of trace amounts of mercuric ions (Hg(2+)) in aqueous solutions. This method enables rapid, linear detection (the linear correlation coefficients are 0.9972 of ΔF = 257.09 + 3.58 cHg(2+) for Ac-FFACD and 0.9994 of ΔF = 48.13 + 32.96 cHg(2+) for Fmoc-FFACD) with the Hg(2+) limit of detection at 300.85 ng·L(-1) and 32.09 ng·L(-1) for Ac-FFACD and Fmoc-FFACD, respectively. The supramolecular, self-assembled nanowires, fabricated from the two aromatic pentapeptides and having encapsulated QDs, exhibit superior properties attributable to the large loading capacity and the coordination sites of these peptides with Hg(2+). These structures can serve as novel Hg(2+) sensors and have possible applications for detection of various targets in scientific and engineering systems.

  4. In-Situ Heating Decrease Kinetics of Aliphatic Hydrocarbons in Tagish Lake Meteorite by Micro-FTIR

    NASA Technical Reports Server (NTRS)

    Kebukawa, Y.; Nakashima, S.; Zolensky, M. E.

    2005-01-01

    Carbonaceous chondrites are known to contain up to 3wt.% C, the major part of which corresponds to a macromolecular organic fraction. Chondritic organic matter is based on small aromatic units, cross-linked by short aliphatic chains rather than large clusters of polyaromatic structures. Two main characteristic features of those organics measured by FTIR are: (1) an equivalent intensity of the asymmetric stretching mode absorptions for CH3 (2960/cm) and CH2 (2920/cm) and (2) a lack of aromatic CH-stretching mode (3040/cm). Tagish Lake is a new type of water- and carbon-rich type 2 carbonaceous chondrite. Its total carbon content is approx. 5 wt%, of which the organic carbon content reaches approx. 1.3 wt%. Tagish Lake may have never experienced temperatures higher than 120 C after formation of organics based on the disappearance of infrared (IR) organic peaks in step heating experiments. Here we report in-situ kinetic heating experiments of organics in Tagish Lake by micro-FTIR to characterize the nature of aliphatic hydrocarbons and their thermal stabilities.

  5. Hollow-fiber liquid-phase microextraction coupled with miniature capillary electrophoresis for the trace analysis of four aliphatic aldehydes in water samples.

    PubMed

    Li, Ying; Yi, Fan; Zheng, Yiliang; Wang, Yu; Ye, Jiannong; Chu, Qingcui

    2015-08-01

    An environmentally friendly method for the trace analysis of four aliphatic aldehydes as water disinfection byproducts has been developed based on hollow-fiber liquid-phase microextraction followed by miniature capillary electrophoresis with amperometric detection. After derivatization with 2-thiobarbituric acid, four aliphatic aldehydes (formaldehyde, acetaldehyde, propylaldehyde, and butyraldehyde) became detectable by the amperometric detector. Under the optimum conditions, four aliphatic aldehydes can be well separated from the coexisting interferents as well as their homologs (pentanal, glyoxal, and methyl-glyoxal), and the limits of detection (S/N = 3) could reach sub-nanogram-per-milliliter level based on hollow-fiber liquid-phase microextraction. The proposed method has been applied for the analyses of above four aliphatic aldehydes in different water samples such as drinking water, tap water, and river water, and the average recoveries were in the range of 90-113%, providing an alternative to conventional and microchip capillary electrophoresis approaches.

  6. A hydroxycinnamoyltransferase responsible for synthesizing suberin aromatics in Arabidopsis

    PubMed Central

    Gou, Jin-Ying; Yu, Xiao-Hong; Liu, Chang-Jun

    2009-01-01

    Suberin, a polyester polymer in the cell wall of terrestrial plants, controls the transport of water and nutrients and protects plant from pathogenic infections and environmental stresses. Structurally, suberin consists of aliphatic and aromatic domains; p-hydroxycinnamates, such as ferulate, p-coumarate, and/or sinapate, are the major phenolic constituents of the latter. By analyzing the “wall-bound” phenolics of mutant lines of Arabidopsis deficient in a family of acyl-CoA dependent acyltransferase (BAHD) genes, we discovered that the formation of aromatic suberin in Arabidopsis, primarily in seed and root tissues, depends on a member of the BAHD superfamily of enzymes encoded by At5g41040. This enzyme exhibits an ω-hydroxyacid hydroxycinnamoyltransferase activity with an in vitro kinetic preference for feruloyl-CoA and 16-hydroxypalmitic acid. Knocking down or knocking out the At5g41040 gene in Arabidopsis reduces specifically the quantity of ferulate in suberin, but does not affect the accumulation of p-coumarate or sinapate. The loss of the suberin phenolic differentially affects the aliphatic monomer loads and alters the permeability and sensitivity of seeds and roots to salt stress. This highlights the importance of suberin aromatics in the polymer's function. PMID:19846769

  7. Cloud condensation nuclei (CCN) activity of aliphatic amine secondary aerosol

    NASA Astrophysics Data System (ADS)

    Tang, X.; Price, D.; Praske, E.; Vu, D. N.; Purvis-Roberts, K.; Silva, P. J.; Cocker, D. R., III; Asa-Awuku, A.

    2014-06-01

    Aliphatic amines can form secondary aerosol via oxidation with atmospheric radicals (e.g., hydroxyl radical and nitrate radical). The particle can contain both secondary organic aerosol (SOA) and inorganic salts. The ratio of organic to inorganic materials in the particulate phase influences aerosol hygroscopicity and cloud condensation nuclei (CCN) activity. SOA formed from trimethylamine (TMA) and butylamine (BA) reactions with hydroxyl radical (OH) is composed of organic material of low hygroscopicity (single hygroscopicity parameter, κ, ≤ 0.25). Secondary aerosol formed from the tertiary aliphatic amine (TMA) with N2O5 (source of nitrate radical, NO3) contains less volatile compounds than the primary aliphatic amine (BA) aerosol. As relative humidity (RH) increases, inorganic amine salts are formed as a result of acid-base reactions. The CCN activity of the humid TMA-N2O5 aerosol obeys Zdanovskii, Stokes, and Robinson (ZSR) ideal mixing rules. The humid BA + N2O5 aerosol products were found to be very sensitive to the temperature at which the measurements were made within the streamwise continuous-flow thermal gradient CCN counter; κ ranges from 0.4 to 0.7 dependent on the instrument supersaturation (ss) settings. The variance of the measured aerosol κ values indicates that simple ZSR rules cannot be applied to the CCN results from the primary aliphatic amine system. Overall, aliphatic amine aerosol systems' κ ranges within 0.2 < κ < 0.7. This work indicates that aerosols formed via nighttime reactions with amines are likely to produce hygroscopic and volatile aerosol, whereas photochemical reactions with OH produce secondary organic aerosol of lower CCN activity. The contributions of semivolatile secondary organic and inorganic material from aliphatic amines must be considered for accurate hygroscopicity and CCN predictions from aliphatic amine systems.

  8. An Esterase from Anaerobic Clostridium hathewayi Can Hydrolyze Aliphatic-Aromatic Polyesters.

    PubMed

    Perz, Veronika; Hromic, Altijana; Baumschlager, Armin; Steinkellner, Georg; Pavkov-Keller, Tea; Gruber, Karl; Bleymaier, Klaus; Zitzenbacher, Sabine; Zankel, Armin; Mayrhofer, Claudia; Sinkel, Carsten; Kueper, Ulf; Schlegel, Katharina; Ribitsch, Doris; Guebitz, Georg M

    2016-03-15

    Recently, a variety of biodegradable polymers have been developed as alternatives to recalcitrant materials. Although many studies on polyester biodegradability have focused on aerobic environments, there is much less known on biodegradation of polyesters in natural and artificial anaerobic habitats. Consequently, the potential of anaerobic biogas sludge to hydrolyze the synthetic compostable polyester PBAT (poly(butylene adipate-co-butylene terephthalate) was evaluated in this study. On the basis of reverse-phase high-performance liquid chromatography (RP-HPLC) analysis, accumulation of terephthalic acid (Ta) was observed in all anaerobic batches within the first 14 days. Thereafter, a decline of Ta was observed, which occurred presumably due to consumption by the microbial population. The esterase Chath_Est1 from the anaerobic risk 1 strain Clostridium hathewayi DSM-13479 was found to hydrolyze PBAT. Detailed characterization of this esterase including elucidation of the crystal structure was performed. The crystal structure indicates that Chath_Est1 belongs to the α/β-hydrolases family. This study gives a clear hint that also micro-organisms in anaerobic habitats can degrade manmade PBAT.

  9. ELECTRON PARAMAGNETIC RESONANCE OF AROMATIC AND ALIPHATIC NITRO ANIONS IN AQUEOUS SOLUTION

    DTIC Science & Technology

    Adams. 1962, 6p. illus. Kansas U., Lawrence. TRIANGULAR WAVE CYCLIC VOLTAMMETRY , by Z. Galus, H. Y. Lee and Ralph N. Adams. 1962, 10p. illus. Kansas...U., Lawrence. OPERATIONAL AMPLIFIER CIRCUITS FOR CONTROLLED POTENTIAL CYCLIC VOLTAMMETRY , by John R. Alden, James Q. Chambers and Ralph N. Adams...interaction with electrolytically generated benzonitrile negative ion, by P. Ludwig and R. N. Adams Triangular wave cyclic voltammetry , by Z. Galus

  10. A Review on the Genetics of Aliphatic and Aromatic Hydrocarbon Degradation.

    PubMed

    Abbasian, Firouz; Lockington, Robin; Megharaj, Mallavarapu; Naidu, Ravi

    2016-01-01

    Because of the high diversity of hydrocarbons, degradation of each class of these compounds is activated by a specific enzyme. However, most of other downstream enzymes necessary for complete degradation of hydrocarbons maybe common between different hydrocarbons. The genes encoding proteins for degradation of hydrocarbons, including the proteins required for the uptake of these molecules, the specific enzyme used for the initial activation of the molecules and other necessary degrading enzymes are usually arranged as an operon. Although the corresponding genes in many phylogenetic groups of microbial species show different levels of diversity in terms of the gene sequence, the organisation of the genes in the genome or on plasmids and the activation mode (inductive or constitutive), some organisms show identical hydrocarbon-degrading genes, probably as a result of horizontal gene transfer between microorganisms.

  11. Assessment of aliphatic-aromatic copolyester biodegradable mulch films. Part I: field study.

    PubMed

    Kijchavengkul, Thitisilp; Auras, Rafael; Rubino, Maria; Ngouajio, Mathieu; Fernandez, R Thomas

    2008-03-01

    The objective of this work was to study the use of new biodegradable films in agriculture under open field conditions. Three biodegradable mulch films made from modified biodegradable polyester of different thicknesses and colors (black and white) and a conventional low density polyethylene (LDPE) mulch film were used to cover the beds of tomato plants. Changes in physical appearance of the films were recorded as well as changes in their mechanical, optical, and physical properties. Once tomato harvest was completed, the conventional LDPE mulch film was removed and all the tomato plants were cut using a mower. The biodegradable mulch films were plowed into the soil. The change in the appearance of the film was recorded and samples of each film after plowing were characterized according to the properties mentioned above. After the biodegradable films photodegraded, cross-link formation occurred within the films which promoted brittleness. Titanium dioxide, an additive used to produce white color in the films, catalyzed the photodegradation, while carbon black used for black color stabilized the photodegradation. The white films started to degrade after two weeks while it took about eight weeks for the black films to significantly degrade. The black biodegradable film seems to be a more promising alternative as a mulch film because of the comparable yields and weed suppression ability to conventional mulch film.

  12. Assessment of aliphatic-aromatic copolyester biodegradable mulch films. Part II: laboratory simulated conditions.

    PubMed

    Kijchavengkul, Thitisilp; Auras, Rafael; Rubino, Maria; Ngouajio, Mathieu; Fernandez, R Thomas

    2008-04-01

    In a previous paper, we demonstrated that the main mechanism of degradation of poly(butylene adipate-co-terephthalate) (PBAT) biodegradable mulch films when exposed to field conditions was crosslinking due to the photodegradation from solar radiation. The aim of this work was to determine the effect of crosslinking on the biodegradability of PBAT samples. PBAT films were subjected to UV photodegradation in laboratory simulated conditions to investigate the effects of crosslinking and other major changes in the structure and mechanical properties of the films. Crosslinking caused the films to become more brittle and produced a reduction of the tensile strength and percent elongation. Besides the crosslinking degradation mechanism, chain scission also occurred in the samples. After 45d of biodegradation test, the non-crosslinked PBAT sample reached 60% of mineralization. However, the percent mineralization was reduced when samples were crosslinked. The percent mineralization of samples with 10%, 30%, 50%, and 70% gel content was 36%, 43%, 21%, and 24%, respectively. Our results indicate that crosslinking is a key process underlying the degradation of the PBAT film and did affect the biodegradability of the films, since the samples with greater amount of gel content generally showed less percent mineralization in the biodegradation tests.

  13. Heterogeneous allylsilylation of aromatic and aliphatic alkenes catalyzed by proton-exchanged montmorillonite.

    PubMed

    Motokura, Ken; Matsunaga, Shigekazu; Miyaji, Akimitsu; Sakamoto, Yasuharu; Baba, Toshihide

    2010-04-02

    Allylsilylation of an alkene is the only known procedure to install both silyl and allyl groups onto a carbon-carbon double bond directly. Proton-exchanged montmorillonite showed excellent catalytic performances for the allylsilylation of alkenes. For example, the reaction of p-chlorostyrene with allyltrimethylsilane proceeded smoothly to afford the corresponding allylsilylated product in 95% yield. We also attempted to isolate the reaction intermediate on the montmorillonite surface to investigate the reaction mechanism.

  14. Polycyclic aromatic hydrocarbons: determinants of urinary 1-hydroxypyrene glucuronide concentration and risk of colorectal cancer in the Shanghai Women’s Health Study

    PubMed Central

    2013-01-01

    Background Associations between polycyclic aromatic hydrocarbons (PAHs) and colorectal cancer have been reported previously but few studies have characterized PAH exposure using biological measurements. We evaluated colorectal cancer risk in relation to urinary concentration of 1-hydroxypyrene glucuronide (1-OHPG), a polycyclic aromatic hydrocarbon (PAH) metabolite, and assessed determinants of PAH exposure among controls in the Shanghai Women’s Health Study (SWHS). Methods Concentrations of 1-OHPG were measured in spot urine samples collected from 343 colorectal cancer cases and 343 individually matched controls. Questionnaires were administered to collect information on demographic characteristics and reported exposures. Odds ratios were calculated for risk of colorectal cancer in relation to quartiles of urinary 1-OHPG concentration. Potential determinants of natural log-transformed urinary 1-OHPG concentration were evaluated among a combined sample of controls from this study and another nested case–control study in the SWHS (Ntotal=652). Results No statistically significant differences in risk of colorectal cancer by urinary 1-OHPG levels were observed. Among controls, the median (interquartile range) urinary 1-OHPG concentration was 2.01 pmol/mL (0.95-4.09). Active and passive smoking, using coal as a cooking fuel, eating foods that were cooked well done, and recent consumption of fried dough (e.g., yóutiáo) were associated with elevated levels of 1-OHPG, though only active smoking and fried dough consumption achieved statistical significance in multivariate analyses. Conclusions This study does not provide evidence of an association between urinary levels of 1-OHPG and risk of colorectal cancer among women. Several environmental and dietary sources of PAH exposure were identified. Overall, the levels of 1-OHPG in this population of predominantly non-smoking women were considerably higher than levels typically observed among non-smokers in Europe, North

  15. Aliphatic alcohols in spirits inhibit phagocytosis by human monocytes.

    PubMed

    Pál, László; Árnyas, Ervin M; Bujdosó, Orsolya; Baranyi, Gergő; Rácz, Gábor; Ádány, Róza; McKee, Martin; Szűcs, Sándor

    2015-04-01

    A large volume of alcoholic beverages containing aliphatic alcohols is consumed worldwide. Previous studies have confirmed the presence of ethanol-induced immunosuppression in heavy drinkers, thereby increasing susceptibility to infectious diseases. However, the aliphatic alcohols contained in alcoholic beverages might also impair immune cell function, thereby contributing to a further decrease in microbicidal activity. Previous research has shown that aliphatic alcohols inhibit phagocytosis by granulocytes but their effect on human monocytes has not been studied. This is important as they play a crucial role in engulfment and killing of pathogenic microorganisms and a decrease in their phagocytic activity could lead to impaired antimicrobial defence in heavy drinkers. The aim of this study was to measure monocyte phagocytosis following their treatment with those aliphatic alcohols detected in alcoholic beverages. Monocytes were separated from human peripheral blood and phagocytosis of opsonized zymosan particles by monocytes treated with ethanol and aliphatic alcohols individually and in combination was determined. It was shown that these alcohols could suppress the phagocytic activity of monocytes in a concentration-dependent manner and when combined with ethanol, they caused a further decrease in phagocytosis. Due to their additive effects, it is possible that they may inhibit phagocytosis in a clinically meaningful way in alcoholics and episodic heavy drinkers thereby contribute to their increased susceptibility to infectious diseases. However, further research is needed to address this question.

  16. Synthetic fuel aromaticity and staged combustion

    SciTech Connect

    Longanbach, J. R.; Chan, L. K.; Levy, A.

    1982-11-15

    Samples of middle and heavy SRC-II distillates were distilled into 50 C boiling point range fractions. These were characterized by measurements of their molecular weight, elemental analysis and basic nitrogen content and calculation of average molecular structures. The structures typically consisted of 1 to 3 aromatic rings fused to alicyclic rings with short, 1 to 3 carbon aliphatic side chains. The lower boiling fractions contained significant amounts (1 atom/molecule) of oxygen while the heavier fractions contained so few heteroatoms that they were essentially hydrocarbons. Laboratory scale oxidative-pyrolysis experiments were carried out at pyrolysis temperatures of 500 to 1100 C and oxygen concentrations from 0 to 100 percent of stoichiometry. Analysis of liquid products, collected in condensers cooled with liquid nitrogen showed that aromatization is a major reaction in the absence of oxygen. The oxygen-containing materials (phenolics) seem to be more resistant to thermal pyrolysis than unsubstituted aromatics. Nitrogen converts from basic to nonbasic forms at about 500 C. The nonbasic nitrogen is more stable and survives up to 700 C after which it is slowly removed. A recently constructed 50,000 Btu/hr staged combustor was used to study the chemistry of the nitrogen and aromatics. SRC II combustion was studied under fuel-rich, first-stage conditions at air/fuel ratios from 0.6 to 1.0 times stoichiometric. The chemistry of the fuel during combustion calls for further investigation in order to examine the mechanism by which HCN is evolved as a common intermediate for the formation of the nitrogen-containing gaseous combustion products. 25 references, 45 figures, 25 tables.

  17. Metal-Organic Framework with Aromatic Rings Tentacles: High Sulfur Storage in Li-S Batteries and Efficient Benzene Homologues Distinction.

    PubMed

    Li, Meng-Ting; Sun, Yu; Zhao, Kai-Sen; Wang, Zhao; Wang, Xin-Long; Su, Zhong-Min; Xie, Hai-Ming

    2016-12-07

    We designed and fabricated a fluorophore-containing tetradentate carboxylate ligand-based metal-organic framework (MOF) material with open and semiopen channels, which acted as the host for sulfur trapped in Li-S batteries and sensor of benzene homologues. These channels efficiently provide a π-π* conjugated matrix for the charge transfer and guest molecule trapping. The open channel ensured a much higher loading quantitative of sulfur (S content-active material, 72 wt %; electrode, 50.4 wt %) than most of the MOF/sulfur composites, while the semiopen channel possessing aromatic rings tentacles guaranteed an outstanding specific discharge capacity (1092 mA h g(-1) at 0.1 C) accompanied by good cycling stability. To our surprise, benefiting from special π-π* conjugated conditions, compound 1 could be a chemical sensor for benzene homologues, especially for 1,2,4-trimethylbenzene (1,2,4-TMB). This is the first example of MOFs materials serving as a sensor of 1,2,4-TMB among benzene homologues. Our works may be worthy of use for references in other porous materials systems to manufacture more long-acting Li-S batteries and sensitive chemical sensors.

  18. Identification of dinuclear aromatics in the gas oil fraction of Kuwait petroleum

    SciTech Connect

    Ijam, M.J.; Qatami, S.Y.A.; Arif, S.F.

    1988-08-01

    For several decades removal of aromatics from crude oil fractions (e.g. kerosene and lubricating oils) has been practiced in oil refining to produce fuels and lubricants of lower aromatic content and hence of improved quality. These aromatics are suitable raw materials for the manufacture of aromatic solvents, aromatic process oils, high octane gasoline, and as basic materials for making detergents, perfumes and dyes. Detailed study of molecular structure and substituent effects on the retention characteristics of aromatic hydrocarbons have been reported on alumina, silica and various chemically bonded silicas containing -C/sub 18/, -NH/sub 2/, -R(NH)/sub 2//sub 2/, -CN, RCN, RON and phenyl-mercuric acetate for the compound class (ring-numbered) high performance liquid chromatography (2, 3, 8, 12, 24, 28). Previous work in this laboratory has demonstrated that individual normal and branched aliphatic hydrocarbons from kerosene and light gas oil were isolated and identified. This paper describes the extension of this work to cover the separation and identification of aromatic ring classes (mono-, di-, and tri-aromatics) in the gas oil fraction of Kuwait petroleum. Characterization and identification of the major components in the dinuclear aromatics is our primary objective in this study.

  19. Catalytic Asymmetric Hydroamination of Unactivated Internal Olefins to Aliphatic Amines

    PubMed Central

    Yang, Yang; Shi, Shi-Liang; Niu, Dawen; Liu, Peng; Buchwald, Stephen L.

    2015-01-01

    Catalytic assembly of enantiopure aliphatic amines from abundant and readily available precursors has long been recognized as a paramount challenge in synthetic chemistry. Herein, we describe a mild and general copper-catalyzed hydroamination that effectively converts unactivated internal olefins, an important yet unexploited class of abundant feedstock chemicals, into highly enantioenriched α-branched amines (≥ 96% enantiomeric excess) featuring two minimally differentiated aliphatic substituents. This method provides a powerful means to access a broad range of advanced, highly functionalized enantioenriched amines of interest in pharmaceutical research and other areas. PMID:26138973

  20. AROMATIC AND POLYCYCLIC AROMATIC HYDROCARBON FORMATION IN A LAMINAR PREMIXED N-BUTANE FLAME. (R825412)

    EPA Science Inventory

    Abstract

    Experimental and detailed chemical kinetic modeling work has been performed to investigate aromatic and polycyclic aromatic hydrocarbon (PAH) formation pathways in a premixed, rich, sooting, n-butane¯oxygen¯argon burner s...

  1. Geochemistry of polycyclic aromatic hydrocarbons in Columbia River and Washington coastal sediments

    SciTech Connect

    Prahl, F.G.

    1982-01-20

    A field investigation was conducted to determine the origins, dispersal pathways and fates of polycyclic aromatic hydrocarbons (PAH) in a river-influenced coastal marine environment. Complete PAH characterizations were combined with analyses of aliphatic hydrocarbons, organic carbon and nitrogen, lignin, lead-210 and several other parameters to clarify the geochemistry of this class of compounds in the Columbia River basin and the southern Washington continental shelf and slope. 94 references, 18 figures, 24 tables.

  2. Molecular Tracers of Saturated and Polycyclic Aromatic Hydrocarbon Inputs into Central Park Lake, New York City

    PubMed Central

    YAN, BEIZHAN; ABRAJANO, TEOFILO A.; BOPP, RICHARD F.; CHAKY, DAMON A.; BENEDICT, LUCILLE A.; CHILLRUD, STEVEN N.

    2011-01-01

    Saturated hydrocarbons (SH) and polycyclic aromatic hydrocarbons (PAHs) have been quantified in a sediment core obtained from Central Park Lake, New York City. Radionuclides 210Pb and 137Cs were used to assign approximate dates to each individual section in the core. The dating profile based on 210Pb matches very well with the time constraints provided by 137Cs. Radionuclide-derived depositional dates are consistent with temporal information from the petroleum-indicator ratio U/R [the ratio of unresolved complex mixture (UCM) to saturated hydrocarbons in the aliphatic fraction] and the history of fuel use in the NYC area. Ratios of 1,7-dimethylphenanthrane (DMP) to 1,7-DMP plus 2,6-DMP [1,7/(1,7 + 2,6)-DMP], retene to retene plus chrysene [Ret/(Ret + Chy)], and fluoranthene to fluoranthene plus pyrene [Fl/(Fl + Py)] provide additional source discrimination throughout the core. Results show that the ratio U/R is sensitive to petroleum inputs and Ret/(Ret + Chy) is responsive to contributions from softwood combustion, whereas both Fl/(Fl + Py) and 1,7/(1,7 + 2,6)-DMP can be used to discriminate among wood, coal, and petroleum combustion sources. Combined use of these ratios suggests that in New York City, wood combustion dominated 100 years ago, with a shift to coal combustion occurring from the 1900s to the 1950s. Petroleum use began around the 1920s and has dominated since the 1940s. PMID:16201624

  3. Applicability of the theory of thermodynamic similarity to predict the enthalpies of vaporization of aliphatic aldehydes

    NASA Astrophysics Data System (ADS)

    Esina, Z. N.; Korchuganova, M. R.

    2015-06-01

    The theory of thermodynamic similarity is used to predict the enthalpies of vaporization of aliphatic aldehydes. The predicted data allow us to calculate the phase diagrams of liquid-vapor equilibrium in a binary water-aliphatic aldehyde system.

  4. 40 CFR 721.10199 - Substituted aliphatic amine (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... aliphatic amine (PMN P-06-702) is subject to reporting under this section for the significant new uses...-specific cartridge) and should include a particulate filter (N100 if oil aerosols are absent, R100, or P100... (HEPA) filters; supplied-air respirator operated in pressure demand or continuous flow mode and...

  5. 40 CFR 721.10199 - Substituted aliphatic amine (generic).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... aliphatic amine (PMN P-06-702) is subject to reporting under this section for the significant new uses...-specific cartridge) and should include a particulate filter (N100 if oil aerosols are absent, R100, or P100... (HEPA) filters; supplied-air respirator operated in pressure demand or continuous flow mode and...

  6. 40 CFR 721.10199 - Substituted aliphatic amine (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... aliphatic amine (PMN P-06-702) is subject to reporting under this section for the significant new uses...-specific cartridge) and should include a particulate filter (N100 if oil aerosols are absent, R100, or P100... (HEPA) filters; supplied-air respirator operated in pressure demand or continuous flow mode and...

  7. Degradation Characterization of Aliphatic POLYESTERS—IN Vitro Study

    NASA Astrophysics Data System (ADS)

    Vieira, A. C.; Vieira, J. C.; Guedes, R. M.; Marques, A. T.

    2008-08-01

    The most popular and important biodegradable polymers are aliphatic polyesters, such as polylactic acid (PLA), polyglycolic acid (PGA), polycaprolactone (PCL), polyhydoxyalkanoates (PHA's) and polyethylene oxide (PEO). However, each of these has some shortcomings which restrict its applications. Blending techniques are an extremely promising approach which can improve or tune the original properties of the polymers[1]. Aliphatic polyesters are a central class of biodegradable polymers, because hydrolytic and/or enzymatic chain cleavage of these materials leads to α-hydroxyacids, which in most cases are ultimately metabolized in human body. This is particularly useful for controlled release devices and for other biomedical applications like suture fibers and ligaments. For aliphatic polyesters, hydrolysis rates are affected by the temperature, molecular structure, and ester group density as well as by the species of enzyme used. The degree of crystallinity may be a crucial factor, since enzymes attack mainly the amorphous domains of a polymer. Four different aliphatic polyesters were characterized in terms of degradation. Sutures fibers of PGA-PCL, PGA, PLA-PCL and PDO were used in this study. Weight loss, pH, molecular weight, crystallinity and strength were measured after six stages of incubation in distilled water, physiological saline and phosphate buffer solution (PBS). Degradation rate was determined, using a first order kinetic equation for all materials in the three incubation media. A relatively wide range of mechanical properties and degradation rates were observed among the materials studied. PBS was the most aggressive environment for the majority of cases.

  8. Introducing Aliphatic Substitution with a Discovery Experiment Using Competing Electrophiles

    ERIC Educational Resources Information Center

    Curran, Timothy P.; Mostovoy, Amelia J.; Curran, Margaret E.; Berger, Clara

    2016-01-01

    A facile, discovery-based experiment is described that introduces aliphatic substitution in an introductory undergraduate organic chemistry curriculum. Unlike other discovery-based experiments that examine substitution using two competing nucleophiles with a single electrophile, this experiment compares two isomeric, competing electrophiles…

  9. Suppression of the Ethanol Withdrawal Syndrome by Aliphatic Diols

    DTIC Science & Technology

    1979-06-07

    Two halogenated hydrocarbons , alcohols exert their intoxicating properties through an interac- which are amphiphiles like alcohols and diols, were both...induce a virtually identical spectrum of phatic hydrocarbons could not. The data suggest that short- intoxication signs. Because of their pharmacological...their ability to induce to determine if partitioning into membrasps is an important intoxication since 1) alcohols and aliphatic hydrocarbons with

  10. Cloud condensation nuclei activity of aliphatic amine secondary aerosol

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aliphatic amines can form secondary aerosol via oxidation with atmospheric radicals (e.g. hydroxyl radical and nitrate radical). The resulting particle composition can contain both secondary organic aerosol (SOA) and inorganic salts. The fraction of organic to inorganic materials in the particulate ...

  11. 16S rDNA-based probes for two polycyclic aromatic hydrocarbon (PAH)-degrading soil Mycobacteria

    SciTech Connect

    Govindaswami, M.; Feldhake, D.J.; Loper, J.C.

    1994-12-31

    PAHs are a class of widespread pollutants, some of which have been shown to be genotoxic, hence the fate of these compounds in the environment is of considerable interest. Research on the biodegradation of 4 and 5 ring PAHs has been limited by the general lack of microbial isolates or consortia which can completely degrade these toxicants. Heitkamp and Cerniglia have described an oxidative soil Mycobacterium-strain PYR-1 that metabolizes pyrene and fluoranthene more rapidly than the 2 and 3 ring naphthalene and phenanthrene; although some metabolites of benzo-(a)-pyrene (BaP) were detected, no mineralization of BaP was observed. In 1991 Grosser et al. reported the isolation of a Mycobacterium sp. which mineralizes pyrene and also causing some mineralization of BaP. Their study describes a comparative analysis of these two strains, which show very similar colony morphology, growth rate and yellow-orange pigmentation. Genetic differences were shown by DNA amplification fingerprinting (DAF) using two arbitrary GC-rich octanucleotide primers, and by sequence comparison of PCR amplified 16S rDNA, although both strains show similarity closest to that of the genus Mycobacteria. These 16S rDNA sequences are in use for the construction of strain-specific DNA probes to monitor the presence, survival and growth of these isolates in PAH-contaminated soils in studies of biodegradation.

  12. 40 CFR 721.7250 - Polyaziridinyl ester of an aliphatic alcohol (generic).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Polyaziridinyl ester of an aliphatic... Specific Chemical Substances § 721.7250 Polyaziridinyl ester of an aliphatic alcohol (generic). (a... generically as a polyaziridinyl ester of an aliphatic alcohol (PMN P-01-97) is subject to reporting under...

  13. 40 CFR 721.7250 - Polyaziridinyl ester of an aliphatic alcohol (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Polyaziridinyl ester of an aliphatic... Specific Chemical Substances § 721.7250 Polyaziridinyl ester of an aliphatic alcohol (generic). (a... generically as a polyaziridinyl ester of an aliphatic alcohol (PMN P-01-97) is subject to reporting under...

  14. 40 CFR 721.10608 - Aliphatic diisocyanate polymer with alkanediol and alkylglycol (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Aliphatic diisocyanate polymer with... Significant New Uses for Specific Chemical Substances § 721.10608 Aliphatic diisocyanate polymer with.... (1) The chemical substance identified generically as aliphatic diisocyanate polymer with...

  15. 40 CFR 721.10608 - Aliphatic diisocyanate polymer with alkanediol and alkylglycol (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Aliphatic diisocyanate polymer with... Significant New Uses for Specific Chemical Substances § 721.10608 Aliphatic diisocyanate polymer with.... (1) The chemical substance identified generically as aliphatic diisocyanate polymer with...

  16. 40 CFR 721.2098 - Aliphatic polycarboxylic acid metal salt (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Aliphatic polycarboxylic acid metal... Specific Chemical Substances § 721.2098 Aliphatic polycarboxylic acid metal salt (generic). (a) Chemical... as an aliphatic polycarboxylic acid metal salt (PMN P-01-7) is subject to reporting under...

  17. 40 CFR 721.2098 - Aliphatic polycarboxylic acid metal salt (generic).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Aliphatic polycarboxylic acid metal... Specific Chemical Substances § 721.2098 Aliphatic polycarboxylic acid metal salt (generic). (a) Chemical... as an aliphatic polycarboxylic acid metal salt (PMN P-01-7) is subject to reporting under...

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

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Aliphatic polycarboxylic acid metal... Specific Chemical Substances § 721.2098 Aliphatic polycarboxylic acid metal salt (generic). (a) Chemical... as an aliphatic polycarboxylic acid metal salt (PMN P-01-7) is subject to reporting under...

  19. 40 CFR 721.2098 - Aliphatic polycarboxylic acid metal salt (generic).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

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

  20. 40 CFR 721.2098 - Aliphatic polycarboxylic acid metal salt (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Aliphatic polycarboxylic acid metal... Specific Chemical Substances § 721.2098 Aliphatic polycarboxylic acid metal salt (generic). (a) Chemical... as an aliphatic polycarboxylic acid metal salt (PMN P-01-7) is subject to reporting under...

  1. Functional Aromatic Poly(1,3,4-Oxadiazole-Ether)s with Benzimidazole Pendants: Synthesis, Thermal and Dielectric Studies

    PubMed Central

    Ganesh, Shimoga D.; Pai, Vasantakumar K.; Kariduraganavar, Mahadevappa Y.; Jayanna, Madhu B.

    2014-01-01

    Poly(1,3,4-oxadiazole-ether) with reactive carboxylic acid pendants was synthesized from solution polymerization via nucleophilic displacement polycondensation among 2,5-bis(4-fluorophenyl)-1,3,4-oxadiazole (BFPOx) and 4,4′-bis(4-hydroxyphenyl) valeric acid (BHPA). Without altering the polymeric segments, benzimidazole modified poly(1,3,4-oxadiazole-ether)s were prepared by varying stoichiometric ratios of 1,2-phenylenediamine. The molecular structural characterization of these polymers was achieved by, FT-IR, NMR, TGA, elemental analysis, and analytical techniques. The weight-average molecular weight of virgin polymer with carboxylic acid functionality was determined by gel permeation chromatography (GPC) and was found to be 22400 (Mw/Mn = 2.07). All the synthesized polyethers were compressed into pellets and electrical contacts were established to perform dielectric properties. PMID:27437448

  2. A method to obtain the absorption coefficient spectrum of single grain coal in the aliphatic C-H stretching region using infrared transflection microspectroscopy.

    PubMed

    Tonoue, Ryota; Katsura, Makoto; Hamamoto, Mai; Bessho, Hiroki; Nakashima, Satoru

    2014-01-01

    A method was developed to obtain the absorption coefficient spectrum of a grain of coal (as small as 10(-7)) in the region of aliphatic and aromatic C-H stretching bands (2700-3200 cm(-1)) using infrared transflection microspectroscopy. In this method, the complex refractive index n - ik was determined using an optimization algorithm with the Kramers-Kronig transform so that the calculated transflection spectrum from the Fresnel equation corresponded to the measured one. The obtained absorption coefficients were compared with the bulk values determined from the potassium bromide (KBr) pellet measurement method.

  3. Reactions of organoaluminum compounds with acetylene as a method for the synthesis of aliphatic derivatives with a z-disubstituted double bond

    SciTech Connect

    Andreeva, N.I.; Kuchin, A.V.; Tolstikov, G.A.

    1985-11-01

    This paper develops a method for the synthesis of aliphatic compounds with a Z-disubstituted double bond, which are important synthons for the preparation of such natural products as insect pheromones, aromatic principles, etc. In the carbalumination reaction of acetylene Z-alkenyldialkylaluminums are formed selectively. A-Alkenyldialkylaluminums are highly reactive and can readily be converted into Z-allyl alcohols and their ethers, and into Z-iodovinyl derivatives. By the reactions of vinyl organoaluminum compounds with the complex CH/sub 3/COClhaAlCl/sub 3/ E-conjugated ketones were obtained.

  4. Atmospheric reactivity studies of aliphatic amines

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ambient studies of particulate matter have shown that alkyl amines are often present in particles in areas impacted by agricultural emissions. These locations include California’s Central Valley and Inland Empire and Utah’s Cache Valley. These compounds are not typically observed in airsheds that so...

  5. Near-infrared continuum and 3.3 micrometer(s) polycyclic aromatic hydrocarbon imaging of the starburst ring in the type 1 Seyfert galaxy NGC 7469

    NASA Technical Reports Server (NTRS)

    Mazzarella, J. M.; Voit, G. M.; Soifer, B. T.; Matthews, K.; Graham, J. R.; Armus, L.; Shupe, D.

    1994-01-01

    High resolution near-infrared images of the type 1 Seyfert galaxy NGC 7469 have been obtained to probe its dusty nuclear environment. Direct J, H, and K images are relatively featureless, but residual images created by subtracting a smooth model based on best-fitting elliptical isophotes reveal a tight inner spiral whose high surface-brightness portions correspond to a previously detected 3 sec (1 kpc) diameter ring of radio continuum emission. The inner infrared spiral arms extended approximately equal to 4 sec NW and SE from the nucleus, and the NW arm joins up with large-scale spiral structure visible in the R band. The residual images also show a bar-like structure aligned with the brightest infrared/radio hotspots at PA approximately equal to 50 deg. Three infrared hotspots are detected which align remarkably well with 6 cm radio continuum sources. The near-infrared ring and the hotspots are visible in the residual images, and in a high-resolution direct K-band image restored to an effective resolution of 0.65 sec (FWHM) using the Richardson-Lucy algorithm. The infrared hotspots have luminosities of nuL(sub nu) (2.2 micrometer(s)) approximately equal to 10(exp 8) solar luminosity (M(sub k) approximately equal to -16 mag), suggesting they are either giant H II regions or individual supernovae. The two brightest regions may be associated with enhanced star formation triggered by orbit crowding of gas where spiral arms emerge from an inner bar. Narrowband (delta lambda/lambda approximately 1.5%) imaging in the 3.28 micrometer(s) dust emission feature and surrounding continuum confirms the 3 sec diameter 3.28 micrometer(s) emission region detected previously using multiaperture photometry. The extended polycyclic aromatic hydrocarbon (PAH) emission is slightly elongated and aligned with published 1O III1 line emission and 12.5 micrometer(s) continuum emission, apparently tracing the starburst. The presence of approximately equal to 25% of the total 3.28 micrometer(s

  6. THE SPITZER SPECTROSCOPIC SURVEY OF THE SMALL MAGELLANIC CLOUD (S{sup 4}MC): PROBING THE PHYSICAL STATE OF POLYCYCLIC AROMATIC HYDROCARBONS IN A LOW-METALLICITY ENVIRONMENT

    SciTech Connect

    Sandstrom, Karin M.; Bolatto, Alberto D.; Bot, Caroline; Draine, B. T.; Ingalls, James G.; Israel, Frank P.; Tielens, A. G. G. M.; Jackson, James M.; Leroy, Adam K.; Li, Aigen; Rubio, Monica; Simon, Joshua D.; Smith, J. D. T.; Stanimirovic, Snezana; Van Loon, Jacco Th.

    2012-01-01

    We present results of mid-infrared spectroscopic mapping observations of six star-forming regions in the Small Magellanic Cloud (SMC) from the Spitzer Spectroscopic Survey of the SMC (S{sup 4}MC). We detect the mid-IR emission from polycyclic aromatic hydrocarbons (PAHs) in all of the mapped regions, greatly increasing the range of environments where PAHs have been spectroscopically detected in the SMC. We investigate the variations of the mid-IR bands in each region and compare our results to studies of the PAH bands in the SINGS sample and in a sample of low-metallicity starburst galaxies. PAH emission in the SMC is characterized by low ratios of the 6-9 {mu}m features relative to the 11.3 {mu}m feature and weak 8.6 and 17.0 {mu}m features. Interpreting these band ratios in the light of laboratory and theoretical studies, we find that PAHs in the SMC tend to be smaller and less ionized than those in higher metallicity galaxies. Based on studies of PAH destruction, we argue that a size distribution shifted toward smaller PAHs cannot be the result of processing in the interstellar medium, but instead reflects differences in the formation of PAHs at low metallicity. Finally, we discuss the implications of our observations for our understanding of the PAH life-cycle in low-metallicity galaxies-namely that the observed deficit of PAHs may be a consequence of PAHs forming with smaller average sizes and therefore being more susceptible to destruction under typical interstellar medium conditions.

  7. Measurement of the intramolecular isotope effect on aliphatic hydroxylation by Chromobacterium violaceum phenylalanine hydroxylase.

    PubMed

    Panay, Aram J; Fitzpatrick, Paul F

    2010-04-28

    The non-heme iron enzyme phenylalanine hydroxylase from Chromobacterium violaceum has previously been shown to catalyze the hydroxylation of benzylic and aliphatic carbons in addition to the normal aromatic hydroxylation reaction. The intrinsic isotope effect for hydroxylation of 3-cyclochexylalanine by the enzyme was determined in order to gain insight into the reactivity of the iron center. With 3-[(2)H(11)-cyclohexyl]alanine as the substrate, the isotope effect on the k(cat) value was 1, consistent with an additional step in the overall reaction being significantly slower than hydroxylation. Consequently, the isotope effect was determined as an intramolecular effect by measuring the amount of deuterium lost in the hydroxylation of 3-[1,2,3,4,5,6-(2)H(6)-cyclohexyl]alanine. The ratio of 4-HO-cyclohexylalanine that retained deuterium to that which lost one deuterium atom was 2.8. This gave a calculated value of 12.6 for the ratio of the primary deuterium kinetic isotope effect to the secondary isotope effect. This value is consistent with hydrogen atom abstraction by an electrophilic Fe(O) center and a contribution of quantum-mechanical tunneling to the reaction.

  8. Biodegradation of Trihalomethanes and Other Halogenated Aliphatic Compounds

    NASA Technical Reports Server (NTRS)

    Smith, G. B.

    1996-01-01

    The biological dehalogenation of common water pollutants such as trichloromethane (chloroform) and other halogenated aliphatic compounds was the subject of this project. Samples from diverse water environments such as from groundwater contaminated with halogenated compounds and wastewaters from regional treatment plants were studied to identify conditions that favor certain dehalogenation reactions over others. Gene probe analyses of DNA extracted from the dichlormethane-degrading wastewater indicated the presence of the gene coding for dichloromethane dehalogenase, indicating the genetic basis for the dechlorination activity observed. These studies indicate that methanogenic bacteria are the organisms responsible for the chloroform dechlorination. Dechlorination of a common chlorofluorocarbon (CFC-11) was identified in samples taken from a regional aquifer contaminated with halogenated aliphatic compounds.

  9. Lipstick dermatitis due to C18 aliphatic compounds.

    PubMed

    Hayakawa, R; Matsunaga, K; Suzuki, M; Arima, Y; Ohkido, Y

    1987-04-01

    An 18-year-old girl developed cheilitis. She had a past history of lip cream dermatitis, but the cause was not found. Patch tests with 2 lipsticks were strongly positive. Tests with the ingredients were positive to 2 aliphatic compounds, glyceryl diisostearate and diisostearyl malate. Impurities in the materials were suspected as the cause. Analysis by gas chromatography detected 3 chemicals in glyceryl diisostearate and 1 in diisostearyl malate as impurities. Patch testing with the impurities and glyceryl monoisostearate 0.01% pet in glyceryl diisostearate and isostearyl alcohol 0.25% pet in diisostearyl malate were strongly positive. The characteristics common to the 2 chemicals were liquidity at room temperature, branched C18 aliphatic compound and primary alcohol. Chemicals lacking any of the above 3 features did not react.

  10. Aerobic microorganism for the degradation of chlorinated aliphatic hydrocarbons

    DOEpatents

    Fliermans, Carl B.

    1989-01-01

    A chlorinated aliphatic hydrocarbon-degrading microorganism, having American Type Culture Collection accession numbers ATCC 53570 and 53571, in a biologically pure culture aseptically collected from a deep subsurface habitat and enhanced, mineralizes trichloroethylene and tetrachloroethylene to HCl, H.sub.2 O and Co.sub.2 under aerobic conditions stimulated by methane, acetate, methanol, tryptone-yeast extract, propane and propane-methane.

  11. Manganese-Mediated Coupling Reaction of Vinylarenes and Aliphatic Alcohols

    PubMed Central

    Zhang, Wei; Wang, Nai-Xing; Bai, Cui-Bing; Wang, Yan-Jing; Lan, Xing-Wang; Xing, Yalan; Li, Yi-He; Wen, Jia-Long

    2015-01-01

    Alcohols and alkenes are the most abundant and commonly used organic building blocks in the large-scale chemical synthesis. Herein, this is the first time to report a novel and operationally simple coupling reaction of vinylarenes and aliphatic alcohols catalyzed by manganese in the presence of TBHP (tert-butyl hydroperoxide). This coupling reaction provides the oxyalkylated products of vinylarenes with good regioselectivity and accomplishes with the principles of step-economies. A possible reaction mechanism has also been proposed. PMID:26470633

  12. Nucleophilic Aromatic Substitution.

    ERIC Educational Resources Information Center

    Avila, Walter B.; And Others

    1990-01-01

    Described is a microscale organic chemistry experiment which demonstrates one feasible route in preparing ortho-substituted benzoic acids and provides an example of nucleophilic aromatic substitution chemistry. Experimental procedures and instructor notes for this activity are provided. (CW)

  13. Trimerization of aromatic nitriles

    NASA Technical Reports Server (NTRS)

    Hsu, L. C. (Inventor)

    1977-01-01

    Triazine compounds and cross-linked polymer compositions were made by heating aromatic nitriles to a temperature in the range of about 100 C to about 700 C, in the presence of a catalyst or mixture of catalysts. Aromatic nitrile-modified (terminated and/or appended) imide, benzimidazole, imidazopyrrolone, quinoxaline, and other condensation type prepolymers or their precopolymers were made which were trimerized with or without a filler by the aforementioned catalytic trimerization process.

  14. Closed-Shell Polycyclic Aromatic Hydrocarbon Cations: A New Category of Interstellar Polycyclic Aromatic Hydrocarbons

    NASA Technical Reports Server (NTRS)

    Hudgins, Douglas M.; Bauschlicher, Charles W., Jr.; Allamandola, Louis J.; DeVincenzi, Donald (Technical Monitor)

    2001-01-01

    Density functional theory has been employed to calculate the harmonic frequencies and intensities of a range of polycyclic aromatic hydrocarbon (PAH) cations that explore both size and electronic structure effects of the infrared spectroscopic properties of these species. The sample extends the size range of PAH species considered to more than 50 carbon atoms and includes several representatives from each of two heretofore unexplored categories of PAH cations: (1) fully benzenoid PAH cations whose carbon skeleton is composed of an odd number of carbon atoms (C(sub odd) PAHs); and (2) protonated PAH cations (HPAH+). Unlike the radical electronic structures of the PAH cations that have been the subject of previous theoretical and experimental work, the species in these two classes have a closed-shell electronic configuration. The calculated spectra of circumcoronene, C54H18 in both neutral and (radical) cationic form are also reported and compared with those of the other species. Overall, the C(sub odd) PAHs spectra are dominated by strong CC stretching modes near 1600 cm(exp -1) and display spectra that are remarkably insensitive to molecular size. The HPAH+ species evince a more complex spectrum consistent with the added contributions of aliphatic modes and their generally lower symmetry. Finally, for both classes of closed-shell cations, the intensity of the aromatic CH stretching modes is found to increase with molecular size far out of proportion with the number of CH groups, approaching a value more typical of neutral PAHs for the largest species studied.

  15. Indigenous aliphatic amines in the aqueously altered Orgueil meteorite

    NASA Astrophysics Data System (ADS)

    Aponte, José C.; Dworkin, Jason P.; Elsila, Jamie E.

    2015-10-01

    The CI1 Orgueil meteorite is a highly aqueously altered carbonaceous chondrite. It has been extensively studied, and despite its extensive degree of aqueous alteration and some documented instances of contamination, several indigenous organic compounds including amino acids, carboxylic acids, and nucleobases have been detected in its carbon-rich matrix. We recently developed a novel gas chromatographic method for the enantiomeric and compound-specific isotopic analyses of meteoritic aliphatic monoamines in extracts and have now applied this method to investigate the monoamine content in Orgueil. We detected 12 amines in Orgueil, with concentrations ranging from 1.1 to 332 nmol g-1 of meteorite and compared this amine content in Orgueil with that of the CM2 Murchison meteorite, which experienced less parent-body aqueous alteration. Methylamine is four times more abundant in Orgueil than in Murchison. As with other species, the amine content in Orgueil extracts shows less structural diversity than that in Murchison extracts. We measured the compound-specific stable carbon isotopic ratios (δ13C) for 5 of the 12 monoamines detected in Orgueil and found a range of δ13C values from -20 to +59‰. These δ13C values fall into the range of other meteoritic organic compounds, although they are 13C-depleted relative to their counterparts extracted from the Murchison meteorite. In addition, we measured the enantiomeric composition for the chiral monoamines (R)- and (S)-sec-butylamine in Orgueil, and found it was racemic within experimental error, in contrast with the L-enantiomeric excess found for its amino acid structural analog isovaline. The racemic nature of sec-butylamine in Orgueil was comparable to that previously observed in Murchison, and to other CM2 and CR2 carbonaceous chondrites measured in this work (ALH 83100 [CM1/2], LON 94101 [CM2], LEW 90500 [CM2], LAP 02342 [CR2], and GRA 95229 [CR2]). These results allow us to place some constraints on the effects of

  16. Aromatic Polyimide Foam

    NASA Technical Reports Server (NTRS)

    Weiser, Erik S. (Inventor); St.Clair, Terry L. (Inventor); Echigo, Yoshiaki (Inventor); Kaneshiro, Hisayasu (Inventor)

    2000-01-01

    A mechanically undensified aromatic polyimide foam is made from an aromatic polyimide precursor solid residuum and has the following combination of properties: a density according to ASTM D-3574A of about 0.5 pounds/cu.ft to about 20 pounds/cu.ft; a compression strength according to ASTM D-3574C of about 1.5 psi to about 1500 psi; and a limiting oxygen index according to ASTM D-2863 of about 35% oxygen to about 75% oxygen at atmospheric pressure. The aromatic polyimide foam has no appreciable solid inorganic contaminants which are residues of inorganic blowing agents. The aromatic polyimide which constitutes the aromatic polyimide foam has a glass transition temperature (Tg) by differential scanning calorimetry of about 235 C to about 400 C; and a thermal stability of 0 to about 1% weight loss at 204 C as determined by thermogravinietric analysis (TGA). The aromatic polyimide foam has utility as foam insulation and as structural foam, for example, for aeronautical, aerospace and maritime applications.

  17. Cost-Benefit Analysis for Alternatives to Aliphatic Isocyanate Polyurethanes

    NASA Technical Reports Server (NTRS)

    Lewis, Pattie

    2007-01-01

    NASA and Air Force Space Command (AFSPC) have similar missions and therefore similar facilities and structures in similar environments. The standard practice for protecting metallic substrates in atmospheric environments is the application of an applied coating system. The most common topcoats used in coating systems are polyurethanes that contain isocyanates. Isocyanates are classified as potential human carcinogens and are known to cause cancer in animals. The primary objective of this effort was to demonstrate and validate alternatives to aliphatic isocyanate polyurethanes resulting in one or more isocyanate-free coatings qualified for use at AFSPC and NASA installations participating in this project. This Cost-Benefit Analysis (CBA) quantifies the estimated capital and process costs of coating alternatives and cost savings relative to the current coatings. The estimates in this CBA are to be used for assessing the relative merits of the selected alternatives. The actual economic effects at any specific facility will depend on the alternative material or technology implemented, the number of actual applications converted, future workloads, and other factors . The participants initially considered eighteen (18) alternative coatings as described in the Potential Alternatives Report entitled Potential Alternatives Report for Validation of Alternatives to Aliphatic Isocyanate Polyurethanes, prepared by ITB. Of those, 8 alternatives were selected for testing in accordance with the Joint Test Protocol entitled Joint Test Protocol for Validation of Alternatives to Aliphatic Isocyanate Polyurethanes, and the Field Test Plan entitled Field Evaluations Test Plan for Validation of Alternatives 10 Aliphatic Isocyanate Polyurethanes, both of which were prepared by ITB. A joint Test Report entitled Joint Test Report for Validation of Alternatives to Aliphatic Isocyanate Polyurethanes, prepared by ITB, documents the results of the laboratory and field testing, as well as any

  18. Using spin labels to study molecular processes in soils: Covalent binding of aromatic amines to humic acids of soils

    NASA Astrophysics Data System (ADS)

    Aleksandrova, O. N.; Kholodov, V. A.; Perminova, I. V.

    2015-08-01

    Interactions of aliphatic and aromatic amines with soil and humic acids isolated from it are studied by means of spin labels and electron paramagnetic resonance (EPR) spectroscopy. Nitroxyl radicals containing amino groups are used as spin labels. It is found experimentally that aromatic amines are instantaneously converted to the bound state. It is shown that the microareas of their incorporation are characterized by a significant delay in the reduction of the nitroxyl fragment of spin-label molecules, indicating the formation of condensed structures typical of an oxidative binding mechanism. It is concluded that aliphatic amines do not bind to humic acids. It is noted that the studied process allows elucidating the formation of bound xenobiotic residues in soils.

  19. Research on Aromatic Poly

    NASA Astrophysics Data System (ADS)

    Kiebooms, Rafael Hugo Ludo

    1995-11-01

    A detailed analysis of the literature indicated that substituents can only be used at the level of improving properties during processing, that end groups are only important for those polymers where the energy difference between the aromatic and quinoid structure is very small, and that stability of pi delocalisation is the most important tool for the design of low bandgap polymers. From our research it appeared that, based on a detailed NMR and FT-Raman analysis of oligomers and model compounds, the low band gap of PITN could be associated with the quinoid structure. However, a theoretical analysis of the UV-vis data of a series of aromatic isothianaphthene oligomers indicates that a substantial lowering of the band gap can be obtained in planar aromatic isothianaphthene systems. A parallel investigation of PTFITN, a soluble isothianaphthene analogue, gave some indications that this polymer should possess an aromatic structure. The aromatic structure makes it possible that the fluorines probably induce non planarity such that inter ring pi -conjugation is lowered to a considerable extent. This could explain the increased band gap of 2.1eV observed by Swann et al.^{[1] }. Analysis of a series of aza-analogues of PITN revealed that in these materials it should be possible to combine a planar aromatic geometry with enhanced processability. The 4,5-diaza and 4,7-diaza isothianaphthene polymers can therefore be considered as very promising low band gap materials. Finally, we showed that it is possible to combine the aromatic isothianaphthene ring system with another heterocycle such as thiophene in a formal copolymer. Through the development of a highly specific and efficient synthesis route to 1,3-dithienylisothianaphthene (DTI, 4), we established the basis for the further synthesis and study of formal copolymers with tailor-made electronic properties. ftn ^{[1]}M. J. Swann, G. Brooke, D. Bloor. Synth.Met., 55-57, 281-286, (1993).

  20. An overview of the AROMAT campaigns

    NASA Astrophysics Data System (ADS)

    Merlaud, Alexis; Dekemper, Emmanuel; Van Roozendael, Michel; Constantin, Daniel; Georgescu, Lucian; Meier, Andreas; Richter, Andreas; Den Hoed, Mirjam; Allaart, Marc; Boscornea, Andreea; Vajaiac, Sorin; Bellegante, Livio; Nemuc, Anca; Nicolae, Doina; Shaifangar, Reza; Dörner, Steffen; Wagner, Thomas; Stebel, Kerstin; Schuettemeyer, Dirk

    2016-04-01

    The Airborne ROmanian Measurements of Aerosols and Trace gases (AROMAT) campaign and its follow-up AROMAT-2 were held in September 2014 and August 2015, respectively. Both campaigns focused on two geophysical targets: the city of Bucharest and the large power plants of the Jiu Valley, which are located in a rural area 170 km West of Bucharest. These two areas are complementary in terms of emitted chemical species and their spatial distributions. The objectives of the AROMAT campaigns were (i) to test recently developed airborne observation systems dedicated to air quality satellite validation studies such as the AirMAP imaging DOAS system (University of Bremen), the NO2 sonde (KNMI), and the compact SWING whiskbroom imager (BIRA), and (ii) to prepare the validation programme of the future Atmospheric Sentinels, starting with Sentinel-5 Precursor (S5P) to be launched in early summer 2016. We present results from the different airborne instrumentations and from coincident ground-based measurements (lidar, in-situ, and mobile DOAS systems) performed during both campaigns. The AROMAT dataset addresses several of the mandatory products of TROPOMI/S5P, in particular NO2 and SO2 (horizontal distribution and profile from aircraft, plume image with ground-based SO2 and NO2 cameras, transects with mobile DOAS, in-situ), H2CO (mobile MAX-DOAS), and aerosols (lidar, airborne FUBISS-ASA2 sun-photometer, and aircraft in-situ). We investigate the information content of the AROMAT dataset for satellite validation studies based on co-located OMI and GOME-2 data, and simulations of TROPOMI measurements. The experience gained during AROMAT and AROMAT-2 will be used in support of a large-scale TROPOMI/S5P validation campaign in Romania scheduled for summer 2017.

  1. A role for coenzyme M (2-mercaptoethanesulfonic acid) in a bacterial pathway of aliphatic epoxide carboxylation

    PubMed Central

    Allen, Jeffrey R.; Clark, Daniel D.; Krum, Jonathan G.; Ensign, Scott A.

    1999-01-01

    The bacterial metabolism of short-chain aliphatic alkenes occurs via oxidation to epoxyalkanes followed by carboxylation to β-ketoacids. Epoxyalkane carboxylation requires four enzymes (components I–IV), NADPH, NAD+, and a previously unidentified nucleophilic thiol. In the present work, coenzyme M (2-mercaptoethanesulfonic acid), a compound previously found only in the methanogenic Archaea where it serves as a methyl group carrier and activator, has been identified as the thiol and central cofactor of aliphatic epoxide carboxylation in the Gram-negative bacterium Xanthobacter strain Py2. Component I catalyzed the addition of coenzyme M to epoxypropane to form a β-hydroxythioether, 2-(2-hydroxypropylthio)ethanesulfonate. Components III and IV catalyzed the NAD+-dependent stereoselective dehydrogenation of R- and S-enantiomers of 2-(2-hydroxypropylthio)ethanesulfonate to form 2-(2-ketopropylthio)ethanesulfonate. Component II catalyzed the NADPH-dependent cleavage and carboxylation of the β-ketothioether to form acetoacetate and coenzyme M. These findings evince a newfound versatility for coenzyme M as a carrier and activator of alkyl groups longer in chain-length than methane, a function for coenzyme M in a catabolic pathway of hydrocarbon oxidation, and the presence of coenzyme M in the bacterial domain of the phylogenetic tree. These results serve to unify bacterial and Archaeal metabolism further and showcase diverse biological functions for an elegantly simple organic molecule. PMID:10411892

  2. A cometabolic biotransformation model for halogenated aliphatic compounds exhibiting product toxicity

    SciTech Connect

    Alvarez-Cohen, L. ); McCarty, P.L. )

    1991-08-01

    A model is proposed to describe the rate and extent of cometabolic transformation of halogenated aliphatic compounds by resting microbial cells. The finite transformation capacity ({Tc}) of resting cells, which appears to be associated with cometabolic oxidation of many halogenated aliphatic compounds, is used to incorporate the effects of product toxicity and reductant supply into a modified expression of Monod kinetics. Applicability of the model of trichloroethylene transformation by resting cells from a mixed methanotrophic culture is evaluated by comparison with experimental data from batch transformation studies conducted over a range of conditions. A visually good and statistically reasonable fit was obtained between the experimental data and model predictions both with cells alone and with formate added as an exogenous reductant source. A comparison of parameter estimates (k and K{sub s}) derived by use of the cometabolic transformation model and those derived by use of conventional linearized Monod techniques (Lineweaver-Burk and concentration-normalized equations) indicates that, for reactions involving a finite transformation capacity, the linearized Monod equations yield artificially elevated parameters estimates.

  3. Preliminary chemical analysis and biological testing of materials from the HRI catalytic two-stage liquefaction (CTSL) process. [Aliphatic hydrocarbons

    SciTech Connect

    Later, D.W.; Wilson, B.W.

    1985-01-01

    Coal-derived materials from experimental runs of Hydrocarbon Research Incorporated's (HRI) catalytic two-stage liquefaction (CTSL) process were chemically characterized and screened for microbial mutagenicity. This process differs from two-stage coal liquefaction processes in that catalyst is used in both stages. Samples from both the first and second stages were class-fractionated by alumina adsorption chromatography. The fractions were analyzed by capillary column gas chromatography; gas chromatography/mass spectrometry; direct probe, low voltage mass spectrometry; and proton nuclear magnetic resonance spectrometry. Mutagenicity assays were performed with the crude and class fractions in Salmonella typhimurium, TA98. Preliminary results of chemical analyses indicate that >80% CTSL materials from both process stages were aliphatic hydrocarbon and polynuclear aromatic hydrocarbon (PAH) compounds. Furthermore, the gross and specific chemical composition of process materials from the first stage were very similar to those of the second stage. In general, the unfractionated materials were only slightly active in the TA98 mutagenicity assay. Like other coal liquefaction materials investigated in this laboratory, the nitrogen-containing polycyclic aromatic compound (N-PAC) class fractions were responsible for the bulk of the mutagenic activity of the crudes. Finally, it was shown that this activity correlated with the presence of amino-PAH. 20 figures, 9 tables.

  4. The aromatic ene reaction

    PubMed Central

    Niu, Dawen; Hoye, Thomas R.

    2014-01-01

    The ene reaction is a pericyclic process in which an alkene having an allylic hydrogen atom (the ene donor) reacts with a second unsaturated species (the enophile) to form a new product with a transposed π-bond. The aromatic ene reaction, in which the alkene component is embedded in an aromatic ring, has only been reported in a few (four) instances and has proceeded in low yield (≤6%). Here we show efficient aromatic ene reactions in which a thermally generated aryne engages a pendant m-alkylarene substituent to produce a dearomatized isotoluene, itself another versatile but rare reactive intermediate. Our experiments were guided by computational studies that revealed structural features conducive to the aromatic ene process. We proceeded to identify a cascade comprising three reactions: (i) hexadehydro-Diels-Alder (for aryne generation), (ii) intramolecular aromatic ene, and (iii) bimolecular Alder ene. The power of this cascade is evident from the structural complexity of the final products, the considerable scope, and the overall efficiency of these multi-stage, reagent- and byproduct-free, single-pot transformations. PMID:24345944

  5. Efficient removal and mechanisms of water soluble aromatic contaminants by a reduced-charge bentonite modified with benzyltrimethylammonium cation.

    PubMed

    Zhu, Lizhong; Ruan, Xiuxiu; Chen, Baoliang; Zhu, Runliang

    2008-02-01

    A novel strategy utilizing the phenyls interaction and the hydrophobic affinity of available siloxane surface in the interlayer of bentonite was proposed to improve the sorption capabilities of organobentonites for water soluble aromatic contaminants. A unique organobentonite (65BTMA) was synthesized by intercalating benzyltrimethylammonium cation (BTMA(+)) into the interlayer of a reduced-charge bentonite with cation exchange capacity (CEC) of 65 cmol kg(-1). Phenol, aniline and toluene were used as model compounds of water soluble aromatic contaminants. Their respective removal efficiencies by 65BTMA were achieved at 83.3%, 89.2% and 97.3% at the initial concentration of 20 mg l(-1). To reveal the sorption mechanism, sorption characteristics of aromatic contaminants to 65BTMA were compared with that of aliphatic contaminants in similar molecular size. And various organobentonites were prepared by combining TMA(+) (tetramethylammonium), BTMA(+), HTMA(+) (heptyltrimethylammonium) and CTMA(+) (cetyltrimethylammonium) with two bentonites (CEC=108 and 65 cmol kg(-1)). To 65BTMA, sorption magnitudes of aromatic contaminants were much greater than that of aliphatic compounds with similar size; and dramatically higher than those to other organobentonites at low pollutant concentrations. These observations revealed that the strong phenyls interactions contributed significantly to sorb the aqueous soluble aromatic contaminants to 65BTMA (>90%), and which favored to design uniquely powerful sorbents.

  6. Benzene and Beyond: Pursuing the Core of Aromaticity.

    PubMed

    Weininger, Stephen J

    2015-04-01

    Kekulé first suggested a hexagonal structure for benzene in 1865. For over a half-century after, chemists struggled to reconcile proposed structures for benzene and other aromatic compounds with their resistance to chemical transformation and tendency to maintain the type during reaction. The combined structural and reactivity features of these compounds were eventually covered by the term 'aromaticity'. Kekulé, Bamberger and Thiele had each proposed a criterion for aromaticity; all were either empirically contradicted or incapable of evaluation. In the 1930s, two rival quantum mechanical methods succeeded in establishing a physical basis for aromaticity. Using valence bond theory, Pauling attributed benzene's stability to its being a resonance hybrid of several Lewis structures. Calculating resonance energies was challenging but manipulating Lewis structures was not; that procedure provided qualitative insights into aromatic structure and reactivity. Resonance theory appealed especially to organic chemists and eclipsed Hückel's contemporaneous molecular orbital approach, which remained relatively inaccessible. In the 1950s, however, simple rules derived from Hückel's mathematics, combined with proton NMR data, provided seemingly universal criteria for aromaticity. In the event, post-1950 discoveries of non-organic, three-dimensional compounds such as ferrocene and the fullerenes that exhibit aromatic properties led chemists to doubt the utility and universality of 'aromaticity' as a concept. A recent consensus maintains that aromaticity is a multi-variable phenomenon that cannot be reduced to a strict definition, a property it shares with other core chemical concepts such as 'acidity' and 'reactivity'.

  7. Structural studies of aliphatic substituted phthalocyanine-lipid multilayers.

    PubMed

    Zarbakhsh, Ali; Campana, Mario; Mills, David; Webster, John R P

    2010-10-05

    A Langmuir-Blodgett film of aliphatic substituted phthalocyanines on a C18 silane supporting layer coupled onto a silicon substrate has been investigated using neutron reflectometry. This multilayer structure is seen as a possible candidate for phthalocyanine-lipid biosensor devices. The results show the suitability of the C18 ligands as an anchoring layer for the phthalocyanines. The scattering length density profiles demonstrate the effectiveness of a lipid monolayer in partitioning the composition of phthalocyanine layers from that of the bulk liquid. The effectiveness of this barrier is a critical factor in the efficiency of such devices.

  8. A Comprehensive Review of Aliphatic Hydrocarbon Biodegradation by Bacteria.

    PubMed

    Abbasian, Firouz; Lockington, Robin; Mallavarapu, Megharaj; Naidu, Ravi

    2015-06-01

    Hydrocarbons are relatively recalcitrant compounds and are classified as high-priority pollutants. However, these compounds are slowly degraded by a large variety of microorganisms. Bacteria are able to degrade aliphatic saturated and unsaturated hydrocarbons via both aerobic and anaerobic pathways. Branched hydrocarbons and cyclic hydrocarbons are also degraded by bacteria. The aerobic bacteria use different types of oxygenases, including monooxygenase, cytochrome-dependent oxygenase and dioxygenase, to insert one or two atoms of oxygen into their targets. Anaerobic bacteria, on the other hand, employ a variety of simple organic and inorganic molecules, including sulphate, nitrate, carbonate and metals, for hydrocarbon oxidation.

  9. Superconductivity in aromatic hydrocarbons

    NASA Astrophysics Data System (ADS)

    Kubozono, Yoshihiro; Goto, Hidenori; Jabuchi, Taihei; Yokoya, Takayoshi; Kambe, Takashi; Sakai, Yusuke; Izumi, Masanari; Zheng, Lu; Hamao, Shino; Nguyen, Huyen L. T.; Sakata, Masafumi; Kagayama, Tomoko; Shimizu, Katsuya

    2015-07-01

    'Aromatic hydrocarbon' implies an organic molecule that satisfies the (4n + 2) π-electron rule and consists of benzene rings. Doping solid aromatic hydrocarbons with metals provides the superconductivity. The first discovery of such superconductivity was made for K-doped picene (Kxpicene, five benzene rings). Its superconducting transition temperatures (Tc's) were 7 and 18 K. Recently, we found a new superconducting Kxpicene phase with a Tc as high as 14 K, so we now know that Kxpicene possesses multiple superconducting phases. Besides Kxpicene, we discovered new superconductors such as Rbxpicene and Caxpicene. A most serious problem is that the shielding fraction is ⩽15% for Kxpicene and Rbxpicene, and it is often ∼1% for other superconductors. Such low shielding fractions have made it difficult to determine the crystal structures of superconducting phases. Nevertheless, many research groups have expended a great deal of effort to make high quality hydrocarbon superconductors in the five years since the discovery of hydrocarbon superconductivity. At the present stage, superconductivity is observed in certain metal-doped aromatic hydrocarbons (picene, phenanthrene and dibenzopentacene), but the shielding fraction remains stubbornly low. The highest priority research area is to prepare aromatic superconductors with a high superconducting volume-fraction. Despite these difficulties, aromatic superconductivity is still a core research target and presents interesting and potentially breakthrough challenges, such as the positive pressure dependence of Tc that is clearly observed in some phases of aromatic hydrocarbon superconductors, suggesting behavior not explained by the standard BCS picture of superconductivity. In this article, we describe the present status of this research field, and discuss its future prospects.

  10. Arabidopsis thaliana plants with different levels of aliphatic- and indolyl-glucosinolates affect host selection and performance of Bemisia tabaci.

    PubMed

    Markovich, Oshry; Kafle, Dinesh; Elbaz, Moshe; Malitsky, Sergey; Aharoni, Asaph; Schwarzkopf, Alexander; Gershenzon, Jonathan; Morin, Shai

    2013-12-01

    Generalist insects show reduced selectivity when subjected to similar, but not identical, host plant chemical signatures. Here, we produced transgenic Arabidopsis thaliana plants that over-express genes regulating the aliphatic- and indolyl- glucosinolates biosynthetic pathways with either a constitutive (CaMV 35S) or a phloem-specific promoter (AtSUC2). This allowed us to examine how exposure to high levels of aliphatic- or indolyl-glucosinolates in homogenous habitats (leaf cage apparatus containing two wild-type or two transgenic leaves) and heterogeneous habitats (leaf cage apparatus containing one wild-type and one transgenic leaf) affects host selection and performance of Bemsia tabaci, a generalist phloem-feeding insect. Data from homogenous habitats indicated that exposure to A. thaliana plants accumulating high levels of aliphatic- or indolyl-glucosinolates negatively affected the performance of both adult females and nymphs of B. tabaci. Data from heterogeneous habitats indicated that B. tabaci adult females selected for oviposition plants on which their offspring perform better (preference-performance relationship). However, the combinations of wild-type and transgenic plants in heterogeneous habitats increased the period of time until the first choice was made and led to increased movement rate on transgenic plants, and reduced fecundity on wild-type plants. Overall, our findings are consistent with the view that both performance and selectivity of B. tabaci decrease in heterogeneous habitats that contain plants with closely-related chemical signatures.

  11. Oxidations of N-(3-indoleethyl) cyclic aliphatic amines by horseradish peroxidase: the indole ring binds to the enzyme and mediates electron-transfer amine oxidation.

    PubMed

    Ling, Ke-Qing; Li, Wen-Shan; Sayre, Lawrence M

    2008-01-23

    Although oxidations of aromatic amines by horseradish peroxidase (HRP) are well-known, typical aliphatic amines are not substrates of HRP. In this study, the reactions of N-benzyl and N-methyl cyclic amines with HRP were found to be slow, but reactions of N-(3-indoleethyl) cyclic amines were 2-3 orders of magnitude faster. Analyses of pH-rate profiles revealed a dominant contribution to reaction by the amine-free base forms, the only species found to bind to the enzyme. A metabolic study on a family of congeneric N-(3-indoleethyl) cyclic amines indicated competition between amine and indole oxidation pathways. Amine oxidation dominated for the seven- and eight-membered azacycles, where ring size supports the change in hybridization from sp3 to sp2 that occurs upon one-electron amine nitrogen oxidation, whereas only indole oxidation was observed for the six-membered ring congener. Optical difference spectroscopic binding data and computational docking simulations suggest that all the arylalkylamine substrates bind to the enzyme through their aromatic termini with similar binding modes and binding affinities. Kinetic saturation was observed for a particularly soluble substrate, consistent with an obligatory role of an enzyme-substrate complexation preceding electron transfer. The significant rate enhancements seen for the indoleethylamine substrates suggest the ability of the bound indole ring to mediate what amounts to medium long-range electron-transfer oxidation of the tertiary amine center by the HRP oxidants. This is the first systematic investigation to document aliphatic amine oxidation by HRP at rates consistent with normal metabolic turnover, and the demonstration that this is facilitated by an auxiliary electron-rich aromatic ring.

  12. Biotransformation of chlorinated aliphatic compounds by mixed nitrifying cultures

    SciTech Connect

    Wilber, G.G.; Chakkamadathil, S.V.

    1995-12-31

    The ability of pure cultures of nitrifying bacteria, such as Nitrosomonas europaea, to oxidize chlorinated aliphatic compounds has been demonstrated previously in laboratory experiments. In the current study, mixed nitrifying cultures originating from a municipal wastewater plant were also tested for the ability to biotransform chlorinated aliphatic compounds, including trichloroethene (TCE). A number of variables were tested, including the effects of two different concentrations of TCE, the effect of culture density, and the influence of the primary substrate, ammonia, on the initial rate of TCE biotransformation. The primary conclusions of the research include the following. The mixed nitrifying cultures did exhibit the ability to transform TCE, and the initial rate of transformation (before oxygen limitations became significant) was directly proportional to the culture density. In general, the transformation rate of TCE was slightly faster at an initial concentration of 0.1 mg/L than at 1 mg/L. Lastly, high initial ammonia concentrations (300 mg/L) resulted in faster initial rates of TCE transformation than in cultures which started with lower ammonia concentrations.

  13. Short-chain aliphatic ester synthesis using Thermobifida fusca cutinase.

    PubMed

    Su, Lingqia; Hong, Ruoyu; Guo, Xiaojie; Wu, Jing; Xia, Yongmei

    2016-09-01

    Short-chain aliphatic esters are commonly used as fruit flavorings in the food industry. In this study, Thermobifida fusca (T. fusca) cutinase was used for the synthesis of aliphatic esters, and the maximum yield of ethyl caproate reached 99.2% at a cutinase concentration of 50U/ml, 40°C, and water content of 0.5%, representing the highest ester yield to date. The cutinase-catalyzed esterification displayed strong tolerance for water content (up to 8%) and acid concentration (up to 0.8M). At substrate concentrations ⩽0.8M, the ester yield remained above 80%. Moreover, ester yields of more than 98% and 95% were achieved for acids of C3-C8 and alcohols of C1-C6, respectively, indicating extensive chain length selectivity of the cutinase. These results demonstrate the superior ability of T. fusca cutinase to catalyze the synthesis of short-chain esters. This study provides the basis for industrial production of short-chain esters using T. fusca cutinase.

  14. Polycyclovorans algicola gen. nov., sp. nov., an Aromatic-Hydrocarbon-Degrading Marine Bacterium Found Associated with Laboratory Cultures of Marine Phytoplankton

    PubMed Central

    Green, David H.; Nichols, Peter D.; Whitman, William B.; Semple, Kirk T.; Aitken, Michael D.

    2013-01-01

    A strictly aerobic, halotolerant, rod-shaped bacterium, designated strain TG408, was isolated from a laboratory culture of the marine diatom Skeletonema costatum (CCAP1077/1C) by enrichment with polycyclic aromatic hydrocarbons (PAHs) as the sole carbon source. 16S rRNA gene sequence analysis placed this organism within the order Xanthomonadales of the class Gammaproteobacteria. Its closest relatives included representatives of the Hydrocarboniphaga-Nevskia-Sinobacter clade (<92% sequence similarity) in the family Sinobacteraceae. The strain exhibited a narrow nutritional spectrum, preferring to utilize aliphatic and aromatic hydrocarbon compounds and small organic acids. Notably, it displayed versatility in degrading two- and three-ring PAHs. Moreover, catechol 2,3-dioxygenase activity was detected in lysates, indicating that this strain utilizes the meta-cleavage pathway for aromatic compound degradation. Cells produced surface blebs and contained a single polar flagellum. The predominant isoprenoid quinone of strain TG408 was Q-8, and the dominant fatty acids were C16:0, C16:1 ω7c, and C18:1 ω7c. The G+C content of the isolate's DNA was 64.3 mol% ± 0.34 mol%. On the basis of distinct phenotypic and genotypic characteristics, strain TG408 represents a novel genus and species in the class Gammaproteobacteria for which the name Polycyclovorans algicola gen. nov., sp. nov., is proposed. Quantitative PCR primers targeting the 16S rRNA gene of this strain were developed and used to show that this organism is found associated with other species of marine phytoplankton. Phytoplankton may be a natural biotope in the ocean where new species of hydrocarbon-degrading bacteria await discovery and which contribute significantly to natural remediation processes. PMID:23087039

  15. The energetics of tetrahydrocarbazole aromatization over Pd(111): A computational analysis

    NASA Astrophysics Data System (ADS)

    Crawford, P.; Burch, R.; Hardacre, C.; Hindle, K. T.; Hu, P.; Rooney, D. W.

    2008-03-01

    The carbazole moiety is a component of many important pharmaceuticals including anticancer and anti-HIV agents and is commonly utilized in the production of modern polymeric materials with novel photophysical and electronic properties. Simple carbazoles are generally produced via the aromatization of the respective tetrahydrocarbazole (THCZ). In this work, density functional theory calculations are used to model the reaction pathway of tetrahydrocarbazole aromatization over Pd(111). The geometry of each of the intermediate surface species has been determined and how each structure interacts with the metal surface addressed. The reaction energies and barriers of each of the elementary surface reactions have also been calculated, and a detailed analysis of the energetic trends performed. Our calculations have shown that the surface intermediates remain fixed to the surface via the aromatic ring in a manner similar to that of THCZ. Moreover, the aliphatic ring becomes progressively more planer with the dissociation of each subsequent hydrogen atom. Analysis of the reaction energy profile has revealed that the trend in reaction barriers is determined by the two factors: (i) the strength of the dissociating ring-H bond and (ii) the subsequent gain in energy due to the geometric relaxation of the aliphatic ring.

  16. Novel aliphatic lipid-based diesters for use in lubricant formulations: Structure property investigations

    NASA Astrophysics Data System (ADS)

    Raghunanan, Latchmi Cindy

    Structure-property relationships are increasingly valued for the identification of specifically engineered materials with properties optimized for targeted application(s). In this work, linear and branched diesters for use in lubricant formulations are prepared from lipid-based oleochemicals and their structure-property relationships reported. It is shown that the branched diesters possess exceptional physical property profiles, including suppression of crystallization, and are superior alternatives for use in lubricant formulations. For the linear aliphatic diesters, both high and low temperature properties were predictable functions of total chain length, and both were differently influenced by the fatty acid versus diol chain length. Symmetry did not influence either, although thermal stability decreased and thermal transition temperatures increased with increasing saturation. All of the linear diesters demonstrated Newtonian flow behaviour. Viscosity was also predictable as a function of total chain length; any microstructural features due to structural effects were superseded by mass effects.

  17. Aromatic Anchor at an Invariant Hormone-Receptor Interface

    PubMed Central

    Pandyarajan, Vijay; Smith, Brian J.; Phillips, Nelson B.; Whittaker, Linda; Cox, Gabriella P.; Wickramasinghe, Nalinda; Menting, John G.; Wan, Zhu-li; Whittaker, Jonathan; Ismail-Beigi, Faramarz; Lawrence, Michael C.; Weiss, Michael A.

    2014-01-01

    Crystallographic studies of insulin bound to fragments of the insulin receptor have recently defined the topography of the primary hormone-receptor interface. Here, we have investigated the role of PheB24, an invariant aromatic anchor at this interface and site of a human mutation causing diabetes mellitus. An extensive set of B24 substitutions has been constructed and tested for effects on receptor binding. Although aromaticity has long been considered a key requirement at this position, MetB24 was found to confer essentially native affinity and bioactivity. Molecular modeling suggests that this linear side chain can serve as an alternative hydrophobic anchor at the hormone-receptor interface. These findings motivated further substitution of PheB24 by cyclohexanylalanine (Cha), which contains a nonplanar aliphatic ring. Contrary to expectations, [ChaB24]insulin likewise exhibited high activity. Furthermore, its resistance to fibrillation and the rapid rate of hexamer disassembly, properties of potential therapeutic advantage, were enhanced. The crystal structure of the ChaB24 analog, determined as an R6 zinc-stabilized hexamer at a resolution of 1.5 Å, closely resembles that of wild-type insulin. The nonplanar aliphatic ring exhibits two chair conformations with partial occupancies, each recapitulating the role of PheB24 at the dimer interface. Together, these studies have defined structural requirements of an anchor residue within the B24-binding pocket of the insulin receptor; similar molecular principles are likely to pertain to insulin-related growth factors. Our results highlight in particular the utility of nonaromatic side chains as probes of the B24 pocket and suggest that the nonstandard Cha side chain may have therapeutic utility. PMID:25305014

  18. 40 CFR 721.7250 - Polyaziridinyl ester of an aliphatic alcohol (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... alcohol (generic). 721.7250 Section 721.7250 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.7250 Polyaziridinyl ester of an aliphatic alcohol (generic). (a... generically as a polyaziridinyl ester of an aliphatic alcohol (PMN P-01-97) is subject to reporting under...

  19. 40 CFR 721.7250 - Polyaziridinyl ester of an aliphatic alcohol (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... alcohol (generic). 721.7250 Section 721.7250 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.7250 Polyaziridinyl ester of an aliphatic alcohol (generic). (a... generically as a polyaziridinyl ester of an aliphatic alcohol (PMN P-01-97) is subject to reporting under...

  20. 40 CFR 721.7250 - Polyaziridinyl ester of an aliphatic alcohol (generic).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... alcohol (generic). 721.7250 Section 721.7250 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.7250 Polyaziridinyl ester of an aliphatic alcohol (generic). (a... generically as a polyaziridinyl ester of an aliphatic alcohol (PMN P-01-97) is subject to reporting under...

  1. 40 CFR 721.10606 - Alkyl substituted alkanediol polymer with aliphatic and alicyclic diisocyanates (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Alkyl substituted alkanediol polymer... alkanediol polymer with aliphatic and alicyclic diisocyanates (generic). (a) Chemical substance and... substituted alkanediol polymer with aliphatic and alicyclic diisocyanates (PMN P-11-486) is subject...

  2. 40 CFR 721.10606 - Alkyl substituted alkanediol polymer with aliphatic and alicyclic diisocyanates (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Alkyl substituted alkanediol polymer... alkanediol polymer with aliphatic and alicyclic diisocyanates (generic). (a) Chemical substance and... substituted alkanediol polymer with aliphatic and alicyclic diisocyanates (PMN P-11-486) is subject...

  3. 40 CFR 721.10605 - Polyoxyalkylene ether, polymer with aliphatic diisocyanate, homopolymer, alkanol-blocked (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Polyoxyalkylene ether, polymer with..., polymer with aliphatic diisocyanate, homopolymer, alkanol-blocked (generic). (a) Chemical substance and... polyoxyalkylene ether, polymer with aliphatic diisocyanate, homopolymer, alkanol-blocked (PMN P-11-485) is...

  4. 40 CFR 721.10605 - Polyoxyalkylene ether, polymer with aliphatic diisocyanate, homopolymer, alkanol-blocked (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Polyoxyalkylene ether, polymer with..., polymer with aliphatic diisocyanate, homopolymer, alkanol-blocked (generic). (a) Chemical substance and... polyoxyalkylene ether, polymer with aliphatic diisocyanate, homopolymer, alkanol-blocked (PMN P-11-485) is...

  5. Integrated reforming/aromatization process

    SciTech Connect

    Harandi, M.N.; Owen, H.

    1990-06-26

    This patent describes an integrated process for increasing the gasoline yield from a catalytic reforming process. It comprises: charging a naphtha boiling range feedstream to a catalytic reforming reaction zone under reforming conversion conditions; withdrawing a reactor effluent stream from the reforming reaction zone; separating the reactor effluent stream into a hydrogen-rich gas stream and an unstabilized reformate stream; further separating the unstabilized reformate in a fractionator into an overhead stream containing C{sub 4} - components and a bottom stream containing C{sub 6} + components; charging the fractionator overhead stream to a catalytic aromatization zone under aromatization conversion conditions; withdrawing an aromatization zone effluent stream from the aromatization zone; cooling the aromatization zone effluent stream; separating the cooled aromatization zone effluent steam into a C{sub 4} - stream and a C{sub 5} + stream; and refluxing the C{sub 5} + aromatic gasoline stream to the fractionation zone.

  6. A statistical approach to the interpretation of aliphatic hydrocarbon distributions in marine sediments

    USGS Publications Warehouse

    Rapp, J.B.

    1991-01-01

    Q-mode factor analysis was used to quantitate the distribution of the major aliphatic hydrocarbon (n-alkanes, pristane, phytane) systems in sediments from a variety of marine environments. The compositions of the pure end members of the systems were obtained from factor scores and the distribution of the systems within each sample was obtained from factor loadings. All the data, from the diverse environments sampled (estuarine (San Francisco Bay), fresh-water (San Francisco Peninsula), polar-marine (Antarctica) and geothermal-marine (Gorda Ridge) sediments), were reduced to three major systems: a terrestrial system (mostly high molecular weight aliphatics with odd-numbered-carbon predominance), a mature system (mostly low molecular weight aliphatics without predominance) and a system containing mostly high molecular weight aliphatics with even-numbered-carbon predominance. With this statistical approach, it is possible to assign the percentage contribution from various sources to the observed distribution of aliphatic hydrocarbons in each sediment sample. ?? 1991.

  7. Development of single-drop microextraction and simultaneous derivatization followed by GC-MS for the determination of aliphatic amines in tobacco.

    PubMed

    Sha, Yunfei; Meng, Jiaoran; Lin, Huaqing; Deng, Chunhui; Liu, Baizhan

    2010-05-01

    In this work, for the first time, headspace (HS) single-drop microextraction and simultaneous derivatization followed by GC-MS was developed to determine the aliphatic amines in tobacco samples. In the HS extraction procedure, the mixture of derivatization reagent and organic solvent was employed as the extraction solvent for HS single-drop microextraction and in situ derivatization of aliphatic amine in the samples. Fast extraction and simultaneous derivatization of the analytes were performed in a single step, and the obtained derivatives in the microdrop extraction solvent were analyzed by GC-MS. The optimized experiment conditions were: sample preparation temperature of 80 degrees C and time of 30 min, HS extraction solvent (the mixture of benzyl alcohol and 2,3,4,5,6-pentafluorobenzaldehyde) volume of 2.0 microL, extraction time of 90 s. With the optimal conditions, the method validations were also studied. The method has good linearity (R(2) more than 0.99), accepted precision (RSD less than 13%), good recovery (98-104%) and low limit of detection (0.11-0.97 microg/g). Finally, the proposed technique was successfully applied to the analyses of aliphatic amines in tobacco samples of seven different brands. It was further demonstrated that the proposed method offered a simple, low-cost and reliable approach to determine aliphatic amines in tobacco samples.

  8. The impact of the absence of aliphatic glucosinolates on insect herbivory in Arabidopsis.

    PubMed

    Beekwilder, Jules; van Leeuwen, Wessel; van Dam, Nicole M; Bertossi, Monica; Grandi, Valentina; Mizzi, Luca; Soloviev, Mikhail; Szabados, Laszlo; Molthoff, Jos W; Schipper, Bert; Verbocht, Hans; de Vos, Ric C H; Morandini, Piero; Aarts, Mark G M; Bovy, Arnaud

    2008-04-30

    Aliphatic glucosinolates are compounds which occur in high concentrations in Arabidopsis thaliana and other Brassicaceae species. They are important for the resistance of the plant to pest insects. Previously, the biosynthesis of these compounds was shown to be regulated by transcription factors MYB28 and MYB29. We now show that MYB28 and MYB29 are partially redundant, but in the absence of both, the synthesis of all aliphatic glucosinolates is blocked. Untargeted and targeted biochemical analyses of leaf metabolites showed that differences between single and double knock-out mutants and wild type plants were restricted to glucosinolates. Biosynthesis of long-chain aliphatic glucosinolates was blocked by the myb28 mutation, while short-chain aliphatic glucosinolates were reduced by about 50% in both the myb28 and the myb29 single mutants. Most remarkably, all aliphatic glucosinolates were completely absent in the double mutant. Expression of glucosinolate biosynthetic genes was slightly but significantly reduced by the single myb mutations, while the double mutation resulted in a drastic decrease in expression of these genes. Since the myb28myb29 double mutant is the first Arabidopsis genotype without any aliphatic glucosinolates, we used it to establish the relevance of aliphatic glucosinolate biosynthesis to herbivory by larvae of the lepidopteran insect Mamestra brassicae. Plant damage correlated inversely to the levels of aliphatic glucosinolates observed in those plants: Larval weight gain was 2.6 fold higher on the double myb28myb29 mutant completely lacking aliphatic glucosinolates and 1.8 higher on the single mutants with intermediate levels of aliphatic glucosinolates compared to wild type plants.

  9. The Impact of the Absence of Aliphatic Glucosinolates on Insect Herbivory in Arabidopsis

    PubMed Central

    van Dam, Nicole M.; Bertossi, Monica; Grandi, Valentina; Mizzi, Luca; Soloviev, Mikhail; Szabados, Laszlo; Molthoff, Jos W.; Schipper, Bert; Verbocht, Hans; de Vos, Ric C. H.; Morandini, Piero; Aarts, Mark G. M.; Bovy, Arnaud

    2008-01-01

    Aliphatic glucosinolates are compounds which occur in high concentrations in Arabidopsis thaliana and other Brassicaceae species. They are important for the resistance of the plant to pest insects. Previously, the biosynthesis of these compounds was shown to be regulated by transcription factors MYB28 and MYB29. We now show that MYB28 and MYB29 are partially redundant, but in the absence of both, the synthesis of all aliphatic glucosinolates is blocked. Untargeted and targeted biochemical analyses of leaf metabolites showed that differences between single and double knock-out mutants and wild type plants were restricted to glucosinolates. Biosynthesis of long-chain aliphatic glucosinolates was blocked by the myb28 mutation, while short-chain aliphatic glucosinolates were reduced by about 50% in both the myb28 and the myb29 single mutants. Most remarkably, all aliphatic glucosinolates were completely absent in the double mutant. Expression of glucosinolate biosynthetic genes was slightly but significantly reduced by the single myb mutations, while the double mutation resulted in a drastic decrease in expression of these genes. Since the myb28myb29 double mutant is the first Arabidopsis genotype without any aliphatic glucosinolates, we used it to establish the relevance of aliphatic glucosinolate biosynthesis to herbivory by larvae of the lepidopteran insect Mamestra brassicae. Plant damage correlated inversely to the levels of aliphatic glucosinolates observed in those plants: Larval weight gain was 2.6 fold higher on the double myb28myb29 mutant completely lacking aliphatic glucosinolates and 1.8 higher on the single mutants with intermediate levels of aliphatic glucosinolates compared to wild type plants. PMID:18446225

  10. Photopatternable Biodegradable Aliphatic Polyester with Pendent Benzophenone Groups.

    PubMed

    Chen, Dayong; Chang, Chia-Chih; Cooper, Beth; Silvers, Angela; Emrick, Todd; Hayward, Ryan C

    2015-10-12

    Highly efficient photo-cross-linking reactions enable numerous applications in biomaterials. Here, a photopatternable biodegradable aliphatic polyester with benzophenone pendent groups was synthesized by copper-catalyzed alkyne-azide cycloaddition, affording polyesters that undergo UV-induced cross-linking to yield photopatterned films. Using this material, a self-folding multilayer structure containing polyester/hydrogel bilayer hinges was fabricated. Upon swelling of the hydrogel layer, the construct folds into a triangular tube, which subsequently unfolds due to lipase-catalyzed degradation of the polyester layer. The ability to precisely design such degradation-induced structural changes offers potential for biomaterials and medical applications, such as evolving and responsive 2D and 3D tissue engineering scaffolds.

  11. Anaerobic and aerobic treatment of chlorinated, aliphatic compounds

    SciTech Connect

    Long, J.L.; Stensel, H.D.; Ferguson, J.F.; Strand, S.E.; Ongerth, J.E.

    1993-01-01

    Biological degradation of 12 chlorinated aliphatic compounds (CACs) was assessed in bench-top reactors and in serum bottle tests. Three continuously mixed daily batch-fed reactor systems were evaluated: anaerobic, aerobic, and sequential-anaerobic-aerobic (sequential). The anaerobic culture degraded seven of the feed CACs. The specialized aerobic cultures degraded all but three of the highly chlorinated CACs. The sequential system outperformed either of the other systems alone by degrading 10 of the feed CACs: chloroform, carbon tetrachloride, 1,1-dichloroethane, 1,1,1-trichloroethane, hexachloroethane, 1,1-dichloroethylene, trans-1,2-dichloroethylene, trichloroethylene, perchloroethylene, and 1,2,3-trichloropropane, plus the anaerobic metabolites: dichloromethane and cis-1,2-dichloroethylene.

  12. Aqueous infrared carboxylate absorbances: Aliphatic di-acids

    USGS Publications Warehouse

    Cabaniss, S.E.; Leenheer, J.A.; McVey, I.F.

    1998-01-01

    Aqueous attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectra of 18 aliphatic di-carboxylic acids are reported as a function of pH. The spectra show isosbestic points and intensity changes which indicate that Beer's law is obeyed, and peak frequencies lie within previously reported ranges for aqueous carboxylates and pure carboxylic acids. Intensity sharing from the symmetric carboxylate stretch is evident in many cases, so that bands which are nominally due to alkyl groups show increased intensity at higher pH. The asymmetric stretch of the HA- species is linearly related to the microscopic acidity constant of the H2A species, with ??pK 2 intervening atoms). The results suggest that aqueous ATR-FTIR may be able to estimate 'intrinsic' pKa values of carboxylic acids, in addition to providing quantitative estimates of ionization. ?? 1998 Elsevier Science B.V. All rights reserved.

  13. Surface Characterization of Aliphatic Polyester -g- Phosphorylcholine Copolymers

    NASA Astrophysics Data System (ADS)

    Zhang, Xiongfei; Emrick, Todd; Hsu, Shaw L.

    2007-03-01

    In order to control biodegradation behavior of a class of polyesters, hydrophilic functional groups were grafted onto the main chains. Phosphorylcholine (PC) molecules with azide attached at the end were synthesized. Due to their excellent biocompatibility and hydrophilicity, they have been covalently coupled to biodegradable aliphatic polyesters via a ``click'' cycloaddition reaction to produce amphiphilic graft copolymers. A series of copolymers were prepared by varying the molar incorporation of PC groups. Surface properties of the copolymers were examined to further explore their applications in drug delivery systems. Grazing angle reflection infrared spectroscopy was employed to determine segmental orientation at the film surface. XPS was used to verify surface composition. A water adsorption experiment was carried out to determine the water permeation rate. The improvement in hydrophilicity was confirmed by a water contact experiment. Results indicate that the graft copolymers were promising in drug delivery systems.

  14. Localized aliphatic organic material on the surface of Ceres.

    PubMed

    De Sanctis, M C; Ammannito, E; McSween, H Y; Raponi, A; Marchi, S; Capaccioni, F; Capria, M T; Carrozzo, F G; Ciarniello, M; Fonte, S; Formisano, M; Frigeri, A; Giardino, M; Longobardo, A; Magni, G; McFadden, L A; Palomba, E; Pieters, C M; Tosi, F; Zambon, F; Raymond, C A; Russell, C T

    2017-02-17

    Organic compounds occur in some chondritic meteorites, and their signatures on solar system bodies have been sought for decades. Spectral signatures of organics have not been unambiguously identified on the surfaces of asteroids, whereas they have been detected on cometary nuclei. Data returned by the Visible and InfraRed Mapping Spectrometer on board the Dawn spacecraft show a clear detection of an organic absorption feature at 3.4 micrometers on dwarf planet Ceres. This signature is characteristic of aliphatic organic matter and is mainly localized on a broad region of ~1000 square kilometers close to the ~50-kilometer Ernutet crater. The combined presence on Ceres of ammonia-bearing hydrated minerals, water ice, carbonates, salts, and organic material indicates a very complex chemical environment, suggesting favorable environments to prebiotic chemistry.

  15. Localized aliphatic organic material on the surface of Ceres

    NASA Astrophysics Data System (ADS)

    De Sanctis, M. C.; Ammannito, E.; McSween, H. Y.; Raponi, A.; Marchi, S.; Capaccioni, F.; Capria, M. T.; Carrozzo, F. G.; Ciarniello, M.; Fonte, S.; Formisano, M.; Frigeri, A.; Giardino, M.; Longobardo, A.; Magni, G.; McFadden, L. A.; Palomba, E.; Pieters, C. M.; Tosi, F.; Zambon, F.; Raymond, C. A.; Russell, C. T.

    2017-02-01

    Organic compounds occur in some chondritic meteorites, and their signatures on solar system bodies have been sought for decades. Spectral signatures of organics have not been unambiguously identified on the surfaces of asteroids, whereas they have been detected on cometary nuclei. Data returned by the Visible and InfraRed Mapping Spectrometer on board the Dawn spacecraft show a clear detection of an organic absorption feature at 3.4 micrometers on dwarf planet Ceres. This signature is characteristic of aliphatic organic matter and is mainly localized on a broad region of ~1000 square kilometers close to the ~50-kilometer Ernutet crater. The combined presence on Ceres of ammonia-bearing hydrated minerals, water ice, carbonates, salts, and organic material indicates a very complex chemical environment, suggesting favorable environments to prebiotic chemistry.

  16. Aliphatic acetogenin constituents of avocado fruits inhibit human oral cancer cell proliferation by targeting the EGFR/RAS/RAF/MEK/ERK1/2 pathway

    SciTech Connect

    D'Ambrosio, Steven M.; Han, Chunhua; Pan, Li; Douglas Kinghorn, A.; Ding, Haiming

    2011-06-10

    Highlights: {yields} The aliphatic acetogenins [(2S,4S)-2,4-dihydroxyheptadec-16-enyl acetate] (1) and [(2S,4S)-2,4-dihydroxyheptadec-16-ynyl acetate] (2) isolated from avocado fruit inhibit phosphorylation of c-RAF (Ser338) and ERK1/2 (Thr202/Tyr204). {yields} Aliphatic acetogenin 2, but not 1, prevents EGF-induced activation of EGFR (Tyr1173). {yields} Combination of both aliphatic acetogenins synergistically inhibits c-RAF (Ser338) and ERK1/2 (Thr202/Tyr204) phosphorylation and human oral cancer cell proliferation. {yields} The potential anticancer activity of avocado fruits is due to a combination of specific aliphatic acetogenins targeting two key components of the EGFR/RAS/RAF/MEK/ERK1/2 cancer pathway. {yields} Providing a double hit on a critical cancer pathway such as EGFR/RAS/RAF/MEK/ERK1/2 by phytochemicals like those found in avocado fruit could lead to more effective approach toward cancer prevention. -- Abstract: Avocado (Persea americana) fruits are consumed as part of the human diet and extracts have shown growth inhibitory effects in various types of human cancer cells, although the effectiveness of individual components and their underlying mechanism are poorly understood. Using activity-guided fractionation of the flesh of avocado fruits, a chloroform-soluble extract (D003) was identified that exhibited high efficacy towards premalignant and malignant human oral cancer cell lines. From this extract, two aliphatic acetogenins of previously known structure were isolated, compounds 1 [(2S,4S)-2,4-dihydroxyheptadec-16-enyl acetate] and 2 [(2S,4S)-2,4-dihydroxyheptadec-16-ynyl acetate]. In this study, we show for the first time that the growth inhibitory efficacy of this chloroform extract is due to blocking the phosphorylation of EGFR (Tyr1173), c-RAF (Ser338), and ERK1/2 (Thr202/Tyr204) in the EGFR/RAS/RAF/MEK/ERK1/2 cancer pathway. Compounds 1 and 2 both inhibited phosphorylation of c-RAF (Ser338) and ERK1/2 (Thr202/Tyr204). Compound 2, but not

  17. Sodium hypochlorite oxidation of petroleum aliphatic contaminants in calcareous soils.

    PubMed

    Picard, François; Chaouki, Jamal

    2016-02-01

    This research project investigated the sodium hypochlorite (NaClO) oxidation of aliphatic petroleum contaminants (C10-C50) in a calcareous soil (average 5473 ppm C10-C50, 15 wt% Ca), which had been excavated from a contaminated industrial site. The decontamination objective was to lower the C10-C50 concentration to 700 ppm. CO2 acidity was used in the project to boost the NaClO oxidation yield and seems to have played a role in desorbing the natural organic matter. The experimental conditions were a 2- to 16-h reaction time, at room temperature, with a 1 to 12.5 wt% NaClO oxidative solution and a fixed 2:1 solution-to-soil ratio. With a 3 wt% NaClO solution and with a CO2 overhead, the NaClO dosage requirement was maintained below 60 g NaClO/g of oxidized C10-C50 over the entire decontamination range. The strong chlorine smell remaining after the reaction was completed suggests that part of the NaClO requirement can be recycled. Except traces of chloroform, there were no regulation-listed organochloride contaminants detected on either the treated soil samples or leachates and the total count of chlorinated compounds in treated soil samples was below the detection limit of 250 mg/kg. The NaClO oxidation mechanism on aliphatic substrates might be triggered by transition metals, such as manganese, but no attempt has been made to investigate the oxidation mechanism. Further investigations would include a constant-fed NaClO system and other techniques to lower the required NaClO dosage.

  18. Ultra performance liquid chromatography-atmospheric pressure photoionization-tandem mass spectrometry for high-sensitivity and high-throughput analysis of U.S. Environmental Protection Agency 16 priority pollutants polynuclear aromatic hydrocarbons.

    PubMed

    Cai, Sheng-Suan; Syage, Jack A; Hanold, Karl A; Balogh, Michael P

    2009-03-15

    In this work, we demonstrate the utility of ultra performance liquid chromatography-atmospheric pressure photoionization-tandem mass spectrometry (UPLC-APPI-MS/MS) for high-sensitivity and high-throughput analysis of United States Environmental Protection Agency (U.S. EPA) 16 priority pollutants polycyclic aromatic hydrocarbons (PAHs). Analyses were performed on a Waters Acquity-TQD equipped with Syagen's PhotoMate APPI source. All 16 PAHs were analyzed on column in approximately 3.5 min with excellent chromatographic separation for all PAH isomers and with low picogram detection limits on column for all analytes using chlorobenzene as a dopant. Dynamic linear ranges were evaluated and found to cover at least 3-4 orders of magnitude. In comparison with the existing U.S. EPA methods, this approach improves instrument sample throughput by at least 10-fold.

  19. 40 CFR 721.10190 - Formaldehyde, polymer with aliphatic diamine and phenol, reaction products with 4-methyl-2...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Formaldehyde, polymer with aliphatic... Formaldehyde, polymer with aliphatic diamine and phenol, reaction products with 4-methyl-2-pentanone (generic... identified generically as formaldehyde, polymer with aliphatic diamine and phenol, reaction products with...

  20. 40 CFR 721.10190 - Formaldehyde, polymer with aliphatic diamine and phenol, reaction products with 4-methyl-2...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Formaldehyde, polymer with aliphatic... Formaldehyde, polymer with aliphatic diamine and phenol, reaction products with 4-methyl-2-pentanone (generic... identified generically as formaldehyde, polymer with aliphatic diamine and phenol, reaction products with...

  1. 40 CFR 721.10190 - Formaldehyde, polymer with aliphatic diamine and phenol, reaction products with 4-methyl-2...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Formaldehyde, polymer with aliphatic... Formaldehyde, polymer with aliphatic diamine and phenol, reaction products with 4-methyl-2-pentanone (generic... identified generically as formaldehyde, polymer with aliphatic diamine and phenol, reaction products with...

  2. Presence and potential significance of aromatic-ketone groups in aquatic humic substances

    USGS Publications Warehouse

    Leenheer, J.A.; Wilson, M.A.; Malcolm, R.L.

    1987-01-01

    Aquatic humic- and fulvic-acid standards of the International Humic Substances Society were characterized, with emphasis on carbonyl-group nature and content, by carbon-13 nuclear-magnetic-resonance spectroscopy, proton nuclear-magnetic-resonance spectroscopy, and infrared spectroscopy. After comparing spectral results of underivatized humic and fulvic acids with spectral results of chemically modified derivatives, that allow improved observation of the carbonyl group, the data clearly indicated that aromatic ketone groups comprised the majority of the carbonyl-group content. About one ketone group per monocyclic aromatic ring was determined for both humic and fulvic acids. Aromatic-ketone groups were hypothesized to form by photolytic rearrangements and oxidation of phenolic ester and hydrocarbon precursors; these groups have potential significance regarding haloform formation in water, reactivity resulting from active hydrogen of the methyl and methylene adjacent to the ketone groups, and formation of hemiketal and lactol structures. Aromatic-ketone groups also may be the point of attachment between aliphatic and aromatic moieties of aquatic humic-substance structure. ?? 1987.

  3. Peripherally hydrogenated neutral polycyclic aromatic hydrocarbons as carriers of the 3 micron interstellar infrared emission complex: results from single-photon infrared emission spectroscopy.

    PubMed

    Wagner, D R; Kim, H S; Saykally, R J

    2000-12-20

    Infrared emission spectra of five gas-phase UV laser-excited polycyclic aromatic hydrocarbons (PAHs) containing aliphatic hydrogens are compared with the main 3.3 microns and associated interstellar unidentified infrared emission bands (UIRs). We show that neutral PAHs can account for the majority of the 3 microns emission complex while making little contribution to the other UIR bands; peripherally hydrogenated PAHs produce a better match to astrophysical data than do those containing methyl side groups; 3.4 microns plateau emission is shown to be a general spectral feature of vibrationally excited PAHs containing aliphatic hydrogens, especially those containing methyl groups; and finally, hot-band and overtone emissions arising from aromatic C-H vibrations are not observed in laboratory emission spectra, and therefore, in contrast to current assignments, are not expected to be observed in the UIRs.

  4. Biomolecular NMR using a microcoil NMR probe--new technique for the chemical shift assignment of aromatic side chains in proteins.

    PubMed

    Peti, Wolfgang; Norcross, James; Eldridge, Gary; O'Neil-Johnson, Mark

    2004-05-12

    A specially designed microcoil probe for use in biomolecular NMR spectroscopy is presented. The microcoil probe shows a mass-based sensitivity increase of a minimal factor of 7.5, allowing for the first time routine biomolecular NMR spectroscopy with microgram amounts of proteins. In addition, the exceptional radio frequency capabilities of this probe allowed us to record an aliphatic-aromatic HCCH-TOCSY spectrum for the first time. Using this spectrum, the side chains of aliphatic and aromatic amino acids can be completely assigned using only a single experiment. Using the conserved hypothetical protein TM0979 from Thermotoga maritima, we demonstrate the capabilities of this microcoil NMR probe to completely pursue the sequence specific backbone assignment with less than 500 microg of (13)C,(15)N labeled protein.

  5. Peripherally hydrogenated neutral polycyclic aromatic hydrocarbons as carriers of the 3 micron interstellar infrared emission complex: results from single-photon infrared emission spectroscopy

    NASA Technical Reports Server (NTRS)

    Wagner, D. R.; Kim, H. S.; Saykally, R. J.

    2000-01-01

    Infrared emission spectra of five gas-phase UV laser-excited polycyclic aromatic hydrocarbons (PAHs) containing aliphatic hydrogens are compared with the main 3.3 microns and associated interstellar unidentified infrared emission bands (UIRs). We show that neutral PAHs can account for the majority of the 3 microns emission complex while making little contribution to the other UIR bands; peripherally hydrogenated PAHs produce a better match to astrophysical data than do those containing methyl side groups; 3.4 microns plateau emission is shown to be a general spectral feature of vibrationally excited PAHs containing aliphatic hydrogens, especially those containing methyl groups; and finally, hot-band and overtone emissions arising from aromatic C-H vibrations are not observed in laboratory emission spectra, and therefore, in contrast to current assignments, are not expected to be observed in the UIRs.

  6. Sensitive, accurate and rapid detection of trace aliphatic amines in environmental samples with ultrasonic-assisted derivatization microextraction using a new fluorescent reagent for high performance liquid chromatography.

    PubMed

    Chen, Guang; Liu, Jianjun; Liu, Mengge; Li, Guoliang; Sun, Zhiwei; Zhang, Shijuan; Song, Cuihua; Wang, Hua; Suo, Yourui; You, Jinmao

    2014-07-25

    A new fluorescent reagent, 1-(1H-imidazol-1-yl)-2-(2-phenyl-1H-phenanthro[9,10-d]imidazol-1-yl)ethanone (IPPIE), is synthesized, and a simple pretreatment based on ultrasonic-assisted derivatization microextraction (UDME) with IPPIE is proposed for the selective derivatization of 12 aliphatic amines (C1: methylamine-C12: dodecylamine) in complex matrix samples (irrigation water, river water, waste water, cultivated soil, riverbank soil and riverbed soil). Under the optimal experimental conditions (solvent: ACN-HCl, catalyst: none, molar ratio: 4.3, time: 8 min and temperature: 80°C), micro amount of sample (40 μL; 5mg) can be pretreated in only 10 min, with no preconcentration, evaporation or other additional manual operations required. The interfering substances (aromatic amines, aliphatic alcohols and phenols) get the derivatization yields of <5%, causing insignificant matrix effects (<4%). IPPIE-analyte derivatives are separated by high performance liquid chromatography (HPLC) and quantified by fluorescence detection (FD). The very low instrumental detection limits (IDL: 0.66-4.02 ng/L) and method detection limits (MDL: 0.04-0.33 ng/g; 5.96-45.61 ng/L) are achieved. Analytes are further identified from adjacent peaks by on-line ion trap mass spectrometry (MS), thereby avoiding additional operations for impurities. With this UDME-HPLC-FD-MS method, the accuracy (-0.73-2.12%), precision (intra-day: 0.87-3.39%; inter-day: 0.16-4.12%), recovery (97.01-104.10%) and sensitivity were significantly improved. Successful applications in environmental samples demonstrate the superiority of this method in the sensitive, accurate and rapid determination of trace aliphatic amines in micro amount of complex samples.

  7. The unique aromatic catabolic genes in sphingomonads degrading polycyclic aromatic hydrocarbons (PAHs).

    PubMed

    Pinyakong, Onruthai; Habe, Hiroshi; Omori, Toshio

    2003-02-01

    Many members of the sphingomonad genus isolated from different geological areas can degrade a wide variety of polycyclic aromatic hydrocarbons (PAHs) and related compounds. These sphingomonads such as Sphingobium yanoikuyae strain B1, Novosphingobium aromaticivorans strain F199, and Sphingobium sp. strain P2 have been found to possess a unique group of genes for aromatic degradation, which are distantly related with those in pseudomonads and other genera reported so far both in sequence homology and gene organization. Genes for aromatics degradation in these sphingomonads are complexly arranged; the genes necessary for one degradation pathway are scattered through several clusters. These aromatic catabolic gene clusters seem to be conserved among many other sphingomonads such as Sphingobium yanoikuyae strain Q1, Sphingomonas paucimobilis strain TNE12, S. paucimobilis strain EPA505, Sphingobium agrestis strain HV3, and Sphingomonas chungbukensis strain DJ77. Furthermore, some genes for naphthalenesulfonate degradation found in Sphingomonas xenophaga strain BN6 also share a high sequence homology with their homologues found in these sphingomonads. On the other hand, protocatechuic catabolic gene clusters found in fluorene-degrading Sphingomonas sp. strain LB126 appear to be more closely related with those previously found in lignin-degrading S. paucimobilis SYK-6 than the genes in this group of sphingomonads. This review summarizes the information on the distribution of these strains and relationships among their aromatic catabolic genes.

  8. Polyimidazoles via aromatic nucleophilic displacement

    NASA Technical Reports Server (NTRS)

    Connell, John W. (Inventor); Hergenrother, Paul M. (Inventor)

    1991-01-01

    Polyimidazoles (Pl) are prepared by the aromatic nucleophilic displacement reaction of di(hydroxyphenyl)imidazole monomers with activated aromatic dihalides or activated aromatic dinitro compounds. The reactions are carried out in polar aprotic solvents such as N,N-dimethylacetamide, sulfolane, N-methylpyrroldinone, dimethylsulfoxide, or diphenylsulfone using alkali metal bases such as potassium carbonate at elevated temperature under nitrogen. The di(hydroxyphenyl)imidazole monomers are prepared by reacting an aromatic aldehyde with a dimethoxybenzil or by reacting an aromatic dialdehyde with a methoxybenzil in the presence of ammonium acetate. The di(methoxyphenyl)imidazole is subsequently treated with aqueous hydrobromic acid to give the di(hydroxyphenyl)imidazole monomer. This synthetic route has provided high molecular weight Pl of new chemical structure, is economically and synthetically more favorable than other routes, and allows for facile chemical structure variation due to the availability of a large variety of activated aromatic dihalides and dinitro compounds.

  9. Polyimidazoles via aromatic nucleophilic displacement

    NASA Technical Reports Server (NTRS)

    Connell, John W. (Inventor); Hergenrother, Paul M. (Inventor)

    1992-01-01

    Polyimidazoles (PI) are prepared by the aromatic nucleophilic displacement reaction of di(hydroxyphenyl) imidazole monomers with activated aromatic dihalides or activated aromatic dinitro compounds. The reactions are carried out in polar aprotic solvents such as N,N-dimethyl acetamide, sulfolane, N-methylpyrrolidinone, dimethylsulfoxide, or diphenylsulfone using alkali metal bases such as potassium carbonate at elevated temperatures under nitrogen. The di(hydroxyphenyl) imidazole monomers are prepared by reacting an aromatic aldehyde with a dimethoxybenzil or by reacting an aromatic dialdehyde with a methoxybenzil in the presence of ammonium acetate. The di(methoxyphenyl) imidazole is subsequently treated with aqueous hydrobromic acid to give the di(hydroxphenyl) imidazole monomer. This synthetic route has provided high molecular weight PI of new chemical structure, is economically and synthetically more favorable than other routes, and allows for facile chemical structure variation due to the availability of a large variety of activated aromatic dihalides and dinitro compounds.

  10. Aliphatic structure of humic acids; a clue to their origin

    USGS Publications Warehouse

    Hatcher, P.G.; Maciel, G.E.; Dennis, L.W.

    1981-01-01

    Nuclear magnetic resonance spectra (both 1H and 13C) of humic acids from diverse depositional environments indicate the presence of aromatic chemical structures, most likely derived from lignin of vascular plants, and complex, paraffinic structures, most likely derived from algal or microbial sources. The latter components account for a major fraction of humic acid structures in both terrestrial and aquatic environments, suggesting that algae or microbes play a large role in humification of organic remains from both systems. ?? 1981.

  11. Peptidyl prolyl isomerase Pin1-inhibitory activity of D-glutamic and D-aspartic acid derivatives bearing a cyclic aliphatic amine moiety.

    PubMed

    Nakagawa, Hidehiko; Seike, Suguru; Sugimoto, Masatoshi; Ieda, Naoya; Kawaguchi, Mitsuyasu; Suzuki, Takayoshi; Miyata, Naoki

    2015-12-01

    Pin1 is a peptidyl prolyl isomerase that specifically catalyzes cis-trans isomerization of phosphorylated Thr/Ser-Pro peptide bonds in substrate proteins and peptides. Pin1 is involved in many important cellular processes, including cancer progression, so it is a potential target of cancer therapy. We designed and synthesized a novel series of Pin1 inhibitors based on a glutamic acid or aspartic acid scaffold bearing an aromatic moiety to provide a hydrophobic surface and a cyclic aliphatic amine moiety with affinity for the proline-binding site of Pin1. Glutamic acid derivatives bearing cycloalkylamino and phenylthiazole groups showed potent Pin1-inhibitory activity comparable with that of known inhibitor VER-1. The results indicate that steric interaction of the cyclic alkyl amine moiety with binding site residues plays a key role in enhancing Pin1-inhibitory activity.

  12. Contorted polycyclic aromatics.

    PubMed

    Ball, Melissa; Zhong, Yu; Wu, Ying; Schenck, Christine; Ng, Fay; Steigerwald, Michael; Xiao, Shengxiong; Nuckolls, Colin

    2015-02-17

    CONSPECTUS: This Account describes a body of research in the design, synthesis, and assembly of molecular materials made from strained polycyclic aromatic molecules. The strain in the molecular subunits severely distorts the aromatic molecules away from planarity. We coined the term "contorted aromatics" to describe this class of molecules. Using these molecules, we demonstrate that the curved pi-surfaces are useful as subunits to make self-assembled electronic materials. We have created and continue to study two broad classes of these "contorted aromatics": discs and ribbons. The figure that accompanies this conspectus displays the three-dimensional surfaces of a selection of these "contorted aromatics". The disc-shaped contorted molecules have well-defined conformations that create concave pi-surfaces. When these disc-shaped molecules are substituted with hydrocarbon side chains, they self-assemble into columnar superstructures. Depending on the hydrocarbon substitution, they form either liquid crystalline films or macroscopic cables. In both cases, the columnar structures are photoconductive and form p-type, hole- transporting materials in field effect transistor devices. This columnar motif is robust, allowing us to form monolayers of these columns attached to the surface of dielectrics such as silicon oxide. We use ultrathin point contacts made from individual single-walled carbon nanotubes that are separated by a few nanometers to probe the electronic properties of short stacks of a few contorted discs. We find that these materials have high mobility and can sense electron-deficient aromatic molecules. The concave surfaces of these disc-shaped contorted molecules form ideal receptors for the molecular recognition and assembly with spherical molecules such as fullerenes. These interfaces resemble ball-and-socket joints, where the fullerene nests itself in the concave surface of the contorted disc. The tightness of the binding between the two partners can be

  13. Asphaltene Adsorption onto Self-Assembled Monolayers of Mixed Aromatic

    SciTech Connect

    Turgman-Cohen, S.; Smith, M; Fischer, D; Kilpatrick, P; Genzer, J

    2009-01-01

    The adsorption of asphaltenes onto flat solid surfaces modified with mixed self-assembled monolayers (SAMs) of aliphatic and aromatic trichlorosilanes with varying wettabilities, aromaticities, and thicknesses is tested. The mixed SAMs are characterized by means of contact angle to assess hydrophobicity and molecular and chemical uniformity, spectroscopic ellipsometry to measure the thickness of the films, and near edge X-ray absorption fine structure (NEXAFS) spectroscopy to assess chemical and molecular composition. The molecular characteristics of the adsorbed asphaltene layer and the extent of asphaltene adsorption are determined using NEXAFS and spectroscopic ellipsometry, respectively. The SAMs are formed by depositing phenyl-, phenethyl-, butyl-, and octadecyl- trichlorosilanes from toluene solutions onto silica-coated substrates; the chemical composition and the wettability of the SAM surface is tuned systematically by varying the trichlorosilane composition in the deposition solutions. The adsorption of asphaltenes on the substrates does not correlate strongly with the SAM chemical composition. Instead, the extent of asphaltene adsorption decreases with increasing SAM thickness. This observation suggests that the leading interaction governing the adsorption of asphaltenes is their interaction with the polar silica substrate and that the chemical composition of the SAM is of secondary importance.

  14. Estimating the physicochemical properties of polyhalogenated aromatic and aliphatic compounds using UPPER: part 1. Boiling point and melting point.

    PubMed

    Admire, Brittany; Lian, Bo; Yalkowsky, Samuel H

    2015-01-01

    The UPPER (Unified Physicochemical Property Estimation Relationships) model uses enthalpic and entropic parameters to estimate 20 biologically relevant properties of organic compounds. The model has been validated by Lian and Yalkowsky on a data set of 700 hydrocarbons. The aim of this work is to expand the UPPER model to estimate the boiling and melting points of polyhalogenated compounds. In this work, 19 new group descriptors are defined and used to predict the transition temperatures of an additional 1288 compounds. The boiling points of 808 and the melting points of 742 polyhalogenated compounds are predicted with average absolute errors of 13.56 K and 25.85 K, respectively.

  15. Fluorinated aromatic diamine

    NASA Technical Reports Server (NTRS)

    Jones, Robert J. (Inventor); O'Rell, Michael K. (Inventor); Hom, Jim M. (Inventor)

    1980-01-01

    This invention relates to a novel aromatic diamine and more particularly to the use of said diamine for the preparation of thermally stable high-molecular weight polymers including, for example, polyamides, polyamideimides, polyimides, and the like. This diamine is obtained by reacting a stoichometric amount of a disodium salt of 2,2-bis(4-hydroxyphenyl) hexafluoropropane with 4-chloronitrobenzene to obtain an intermediate, 2,2-bis[4-(4-nitrophenoxy)phenyl] hexafluoropropane, which is reduced to the corresponding 2,2-bis[4-(4-aminophenoxy)phenyl] hexafluoropropane.

  16. Structure and properties of Al-MIL-53-ADP, a breathing MOF based on the aliphatic linker molecule adipic acid.

    PubMed

    Reinsch, Helge; Pillai, Renjith S; Siegel, Renée; Senker, Jürgen; Lieb, Alexandra; Maurin, Guillaume; Stock, Norbert

    2016-03-14

    The new aluminium based metal-organic framework [Al(OH)(O2C-C4H8-CO2)]·H2O denoted as Al-MIL-53-ADP-lp (lp stands for large pore) was synthesised under solvothermal conditions. This solid is an analogue of the archetypical aluminium terephthalate Al-MIL-53 based on the aliphatic single-chain linker molecule adipic acid (H2ADP, hexanedioic acid). In contrast to its aromatic counterparts, Al-MIL-53-ADP exhibits a structural breathing behaviour solely upon dehydration/rehydration. The crystal structure of the anhydrous compound denoted as Al-MIL-53-ADP-np (np stands for narrow pore) was determined by a combination of forcefield-based computations and Rietveld refinement of the powder X-ray diffraction data while the structure of the hydrated form Al-MIL-53-ADP-lp was derived computationally by a combination of force field based methods and Density Functional Theory calculations. Both structures were further supported by (1)H, (13)C and (27)Al high-resolution NMR MAS 1D data coupled again with simulations. Al-MIL-53-ADP was further characterised by means of vibrational spectroscopy, elemental analysis, thermogravimetry and water vapour sorption.

  17. 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

  18. 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(s

  19. Modern and fossil contributions to polycyclic aromatic hydrocarbons in PM₂.₅ from North Birmingham, Alabama in the southeastern U.S.

    PubMed

    Xu, Li; Zheng, Mei; Ding, Xiang; Edgerton, Eric S; Reddy, Christopher M

    2012-02-07

    Analyzing the radiocarbon ((14)C) content of polycyclic aromatic hydrocarbons (PAHs) in atmospheric particulate matter can provide estimates on the source contributions from biomass burning versus fossil fuel. The relative importance of these two sources to ambient PAHs varies considerably across regions and even countries, and hence there is a pressing need to apportion these sources. In this study, we advanced the radiocarbon analysis from bulk carbon to compound class specific radiocarbon analysis (CCSRA) to determine Δ(14)C and δ(13)C values of PAHs in PM(2.5) samples for investigating biomass burning and fossil fuel source contributions to PAHs from one of the Southeastern Aerosol Research and Characterization (SEARCH) sites in North Birmingham (BHM), Alabama during winter (December 2004-February 2005) and summer (June-August 2005) by accelerator mass spectrometry. To compare our ambient samples to known sources, we collected and analyzed fenceline samples from the vicinity of a coke plant in BHM. As expected, PAHs from the coke plant fenceline samples had very low radiocarbon levels. Its Δ(14)C varied from -990 to -970‰, indicating that 97 to 99% were of fossil source. PAHs in the ambient PM(2.5) had Δ(14)C from -968 to -911 ‰, indicating that 92-97% of PAHs were from fossil fuel combustion. These levels indicated the dominance of fossil sources of ambient PAHs. The radiocarbon level of ambient PAHs was higher in winter than in summer. Winter samples exhibited depleted δ(13)C value and enriched Δ(14)C value because of the increased contribution of PAHs from biomass burning source. However, biomass burning contributed more to heavier PAHs (modern source accounting for 6-8%) than lighter ones with a modern contribution of 3%.

  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. Impact of Ferrocene on the Structure of Diesel Exhaust Soot as Probed with Wide-Angle X-ray Scattering and C(1s) NEXAFS Spectroscopy

    SciTech Connect

    Braun,A.; Huggins, F.; Kelly, K.; Mun, B.; Ehrlich, S.; Huffman, G.

    2006-01-01

    We report on the structure of a set of diesel exhaust samples that were obtained from reference diesel fuel and diesel fuel mixed with ferrocene. Characterization was carried out with X-ray absorption spectroscopy (C(1s) NEXAFS) and wide-angle X-ray scattering (WAXS). The reference diesel soot shows a pronounced graphite-like microstructure and molecular structure, with a strong (0 0 2) graphite Bragg reflex and a strong aromatic C{double_bond}C resonance at 285 eV. The mineral matter in the reference soot could be identified as Fe{sub 2}O{sub 3} hematite. The soot specimen from the diesel mixed with ferrocene has an entirely different structure and lacks significantly in graphite-like characteristics. NEXAFS spectra of such soot barely show aromatics but pronounced contributions from aliphatic structures. WAXS patterns show almost no intensity at the Bragg (0 0 2) reflection of graphite, but a strong aliphatic {gamma}-side band. The iron from the ferrocene transforms to Fe{sub 2}O{sub 3} maghemite.

  2. Shape memory polymers based on uniform aliphatic urethane networks

    SciTech Connect

    Wilson, T S; Bearinger, J P; Herberg, J L; Marion III, J E; Wright, W J; Evans, C L; Maitland, D J

    2007-01-19

    Aliphatic urethane polymers have been synthesized and characterized, using monomers with high molecular symmetry, in order to form amorphous networks with very uniform supermolecular structures which can be used as photo-thermally actuable shape memory polymers (SMPs). The monomers used include hexamethylene diisocyanate (HDI), trimethylhexamethylenediamine (TMHDI), N,N,N{prime},N{prime}-tetrakis(hydroxypropyl)ethylenediamine (HPED), triethanolamine (TEA), and 1,3-butanediol (BD). The new polymers were characterized by solvent extraction, NMR, XPS, UV/VIS, DSC, DMTA, and tensile testing. The resulting polymers were found to be single phase amorphous networks with very high gel fraction, excellent optical clarity, and extremely sharp single glass transitions in the range of 34 to 153 C. Thermomechanical testing of these materials confirms their excellent shape memory behavior, high recovery force, and low mechanical hysteresis (especially on multiple cycles), effectively behaving as ideal elastomers above T{sub g}. We believe these materials represent a new and potentially important class of SMPs, and should be especially useful in applications such as biomedical microdevices.

  3. Aliphatic polyesters for medical imaging and theranostic applications.

    PubMed

    Nottelet, Benjamin; Darcos, Vincent; Coudane, Jean

    2015-11-01

    Medical imaging is a cornerstone of modern medicine. In that context the development of innovative imaging systems combining biomaterials and contrast agents (CAs)/imaging probes (IPs) for improved diagnostic and theranostic applications focuses intense research efforts. In particular, the classical aliphatic (co)polyesters poly(lactide) (PLA), poly(lactide-co-glycolide) (PLGA) and poly(ɛ-caprolactone) (PCL), attract much attention due to their long track record in the medical field. This review aims therefore at providing a state-of-the-art of polyester-based imaging systems. In a first section a rapid description of the various imaging modalities, including magnetic resonance imaging (MRI), optical imaging, computed tomography (CT), ultrasound (US) and radionuclide imaging (SPECT, PET) will be given. Then, the two main strategies used to combine the CAs/IPs and the polyesters will be discussed. In more detail we will first present the strategies relying on CAs/IPs encapsulation in nanoparticles, micelles, dendrimers or capsules. We will then present chemical modifications of polyesters backbones and/or polyester surfaces to yield macromolecular imaging agents. Finally, opportunities offered by these innovative systems will be illustrated with some recent examples in the fields of cell labeling, diagnostic or theranostic applications and medical devices.

  4. Aliphatic hydrocarbons in Great Barrier Reef organisms and environment

    NASA Astrophysics Data System (ADS)

    Coates, M.; Connell, D. W.; Bodero, J.; Miller, G. J.; Back, R.

    1986-07-01

    This investigation was undertaken to assess the chemical nature, occurrence, and possible origin of petroleum hydrocarbons in the Great Barrier Reef ecosystem. Aliphatic hydrocarbons in surface sediments, water, and a suite of seven species from widely separated coral reefs in the Great Barrier Reef area were analysed by gas chromatography, and by gas chromatography coupled with mass spectrometry. The hydrocarbons found were substantially of biogenic origin. The major components were n-pentadecane, n-heptadecane, pristane and mono-alkenes based on heptadecane, and were believed to originate from benthic algae and phytoplankton. There was no evidence to suggest that lipid content had any influence on hydrocarbon content. Hydrocarbons from the organisms and sediments have characteristic composition patterns which would be altered by the presence of petroleum hydrocarbons. An unresolved complex mixture, usually considered indicative of petroleum contamination, was found in greater than trace amounts only in Holothuria (sea cucumber) and Acropora (coral) from the Capricorn Group, and in some sediment samples from the Capricorn Group and Lizard Island area.

  5. Organochlorine compounds and aliphatic hydrocarbons in Pacific walrus blubber.

    PubMed

    Seagars, D J; Garlich-Miller, J

    2001-01-01

    Blubber samples were collected from 8 male and 19 female Pacific walrus (Odobenus rosmarus divergens) taken during a 1991 joint USA/USSR cruise traveling widely through the Bering Sea. Dieldrin was found at a level similar to that reported 10 years earlier; oxychlordane was found at a slightly higher concentration than reported previously (Taylor et aL, 1989). Heptachlor epoxide was detected for the first time and found at a low concentration. An initial testing for alpha-, beta- and gamma-HCH detected concentrations similar to those in other Bering Sea pinnipeds. Mean summation of PCB was 0.45 microg g(-1) wet weight in males and 0.16 microg g(-1) in females; only one sample was > 1 microg g(-1). Traces of aliphatic hydrocarbons were detected in all sampled animals, only pristane (x = 0.48 microg g(-1)) was found in concentrations > 1 microg g(-1). Small sample sizes, a lack of samples from immature animals, and uniformly low concentrations of contaminants precluded meaningful analysis of age-related effects and regional differences.

  6. Process for the synthesis of aliphatic alcohol-containing mixtures

    DOEpatents

    Greene, Marvin I.; Gelbein, Abraham P.

    1984-01-01

    A process for the synthesis of mixtures which include saturated aliphatic alcohols is disclosed. In the first step of the process, the first catalyst activation stage, a catalyst, which comprises the oxides of copper, zinc, aluminum, potassium and one or two additional metals selected from the group consisting of chromium, magnesium, cerium, cobalt, thorium and lanthanum, is partially activated. In this step, a reducing gas stream, which includes hydrogen and at least one inert gas, flows past the catalyst at a space velocity of up to 5,000 liters (STP) per hour, per kilogram of catalyst. The partially activated catalyst is then subjected to the second step of the process, second-stage catalyst activation. In this step, the catalyst is contacted by an activation gas stream comprising hydrogen and carbon monoxide present in a volume ratio of 0.5:1 and 4:1, respectively, at a temperature of 200.degree. to 450.degree. C. and a pressure of between 35 and 200 atmospheres. The activation gas flows at a space velocity of from 1,000 to 20,000 liters (STP) per hour, per kilogram of catalyst. Second-stage activation continues until the catalyst is contacted with at least 500,000 liters (STP) of activation gas per kilogram of catalyst. The fully activated catalyst, in the third step of the process, contacts a synthesis gas stream comprising hydrogen and carbon monoxide.

  7. Process for the synthesis of aliphatic alcohol-containing mixtures

    DOEpatents

    Greene, M.I.; Gelbein, A.P.

    1984-10-16

    A process for the synthesis of mixtures which include saturated aliphatic alcohols is disclosed. In the first step of the process, the first catalyst activation stage, a catalyst, which comprises the oxides of copper, zinc, aluminum, potassium and one or two additional metals selected from the group consisting of chromium, magnesium, cerium, cobalt, thorium and lanthanum, is partially activated. In this step, a reducing gas stream, which includes hydrogen and at least one inert gas, flows past the catalyst at a space velocity of up to 5,000 liters (STP) per hour, per kilogram of catalyst. The partially activated catalyst is then subjected to the second step of the process, second-stage catalyst activation. In this step, the catalyst is contacted by an activation gas stream comprising hydrogen and carbon monoxide present in a volume ratio of 0.5:1 and 4:1, respectively, at a temperature of 200 to 450 C and a pressure of between 35 and 200 atmospheres. The activation gas flows at a space velocity of from 1,000 to 20,000 liters (STP) per hour, per kilogram of catalyst. Second-stage activation continues until the catalyst is contacted with at least 500,000 liters (STP) of activation gas per kilogram of catalyst. The fully activated catalyst, in the third step of the process, contacts a synthesis gas stream comprising hydrogen and carbon monoxide.

  8. Project Summary. IN-SITU AQUIFER RESTORATION OF CHLORINATED ALIPHATICS BY METHANOTROPHIC BACTERIA

    EPA Science Inventory

    This project evaluated the potential of an innovative approach to aquifer restoration: enhanced in-situ biotransformation of chlorinated aliphatic solvents by a bacterial community grown on methane under aerobic conditions. The target chlorinated compounds were trichloroethene (...

  9. Field Evaluations Test Plan for Validation of Alternatives to Aliphatic Isocyanate Polyurethanes

    NASA Technical Reports Server (NTRS)

    Lewis, Pattie

    2005-01-01

    The objective of this project is to qualify candidate alternatives to Aliphatic Isocyanate Polyurethane coatings under the specifications for the standard system. This project will compare coating performance of the proposed alternatives to existing coating systems or standards.

  10. PROTONATED POLYCYCLIC AROMATIC HYDROCARBONS REVISITED

    SciTech Connect

    Ricca, Alessandra; Bauschlicher, Charles W. Jr; Allamandola, Louis J. E-mail: Charles.W.Bauschlicher@nasa.gov

    2011-02-01

    We reconsider the contribution that singly protonated polycyclic aromatic hydrocarbons (PAHs; HPAH{sup +}s) might make to the Class A component of the 6.2 {mu}m interstellar emission feature in light of the recent experimental measurements of protonated naphthalene and coronene. Our calculations on the small HPAH{sup +}s have a band near 6.2 {mu}m, as found in experiment. While the larger HPAH{sup +}s still have emission near 6.2 {mu}m, the much larger intensity of the band near 6.3 {mu}m overwhelms the weaker band at 6.2 {mu}m, so that the 6.2 {mu}m band is barely visible. Since the large PAHs are more representative of those in the interstellar medium, our work suggests that large HPAH{sup +}s cannot be major contributors to the observed emission at 6.2 {mu}m (i.e., Class A species). Saturating large PAH cations with hydrogen atoms retains the 6.2 {mu}m Class A band position, but the rest of the spectrum is inconsistent with observed spectra.

  11. Electronic Structure Principles and Aromaticity

    ERIC Educational Resources Information Center

    Chattaraj, P. K.; Sarkar, U.; Roy, D. R.

    2007-01-01

    The relationship between aromaticity and stability in molecules on the basis of quantities such as hardness and electrophilicity is explored. The findings reveal that aromatic molecules are less energetic, harder, less polarizable, and less electrophilic as compared to antiaromatic molecules, as expected from the electronic structure principles.

  12. 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

  13. Synthesis of novel naphthoquinone aliphatic amides and esters and their anticancer evaluation.

    PubMed

    Kongkathip, Boonsong; Akkarasamiyo, Sunisa; Hasitapan, Komkrit; Sittikul, Pichamon; Boonyalai, Nonlawat; Kongkathip, Ngampong

    2013-02-01

    Fourteen new naphthoquinone aliphatic amides and seventeen naphthoquinone aliphatic esters were synthesized in nine to ten steps from 1-hydroxy-2-naphthoic acid with 9-25% overall yield for the amides, and 16-21% overall yield for the esters. The key step of the amide synthesis is a coupling reaction between amine and various aliphatic acids using 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride (DMTMM) as a coupling agent while for the ester synthesis, DCC/DMAP or CDI was used as the coupling reagent between aliphatic acids and naphthoquinone alcohol. Both naphthoquinone amides and esters were evaluated for their anticancer activity against KB cells. It was found that naphthoquinone aliphatic amides showed stronger anticancer activity than those of the esters when the chains are longer than 7-carbon atoms. The optimum chain of amides is expected to be 16-carbon atoms. In addition, naphthoquinone aliphatic esters with α-methyl on the ester moiety possessed much stronger anticancer activity than the straight chains. Decatenation assay revealed that naphthoquinone amide with 16-carbon atoms chain at 15 μM and 20 μM can completely inhibit hTopoIIα activity while at 10 μM the enzyme activity was moderately inhibited. Molecular docking result also showed the same trend as the cytotoxicity and decatenation assay.

  14. Sources and distribution of aliphatic and polyaromatic hydrocarbons in sediments from the Neuquen River, Argentine Patagonia.

    PubMed

    Monza, Liliana B; Loewy, Ruth M; Savini, Mónica C; Pechen de d'Angelo, Ana M

    2013-01-01

    Spatial distribution and probable sources of aliphatic and polyaromatic hydrocarbons (AHs, PAHs) were investigated in surface sediments collected along the bank of the Neuquen River, Argentina. Total concentrations of aliphatic hydrocarbons ranged between 0.41 and 125 μg/g dw. Six stations presented low values of resolved aliphatic hydrocarbons and the n-alkane distribution indexes applied suggested a clear biogenic source. These values can be considered the baseline levels of aliphatic hydrocarbons for the river sediments. This constitutes important information for the assessment of future impacts since a strong impulse in the exploitation of shale gas and shale oil in these zones is nowadays undergoing. For the other 11 stations, a mixture of aliphatic hydrocarbons of petrogenic and biogenic origin was observed. The spatial distribution reflects local inputs of these pollutants with a significant increase in concentrations in the lower course, where two major cities are located. The highest values of total aliphatic hydrocarbons were found in this sector which, in turn, was the only one where individual PAHs were detected.

  15. Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory : determination of polycyclic aromatic hydrocarbon compounds in sediment by gas chromatography/mass spectrometry

    USGS Publications Warehouse

    Olson, Mary C.; Iverson, Jana L.; Furlong, Edward T.; Schroeder, Michael P.

    2004-01-01

    A method for the determination of 28 polycyclic aromatic hydrocarbons (PAHs) and 25 alkylated PAH homolog groups in sediment samples is described. The compounds are extracted from sediment by solvent extraction, followed by partial isolation using high-performance gel permeation chromatography. The compounds are identified and uantitated using capillary-column gas chromatography/mass spectrometry. The report presents performance data for full-scan ion monitoring. Method detection limits in laboratory reagent matrix samples range from 1.3 to 5.1 micrograms per kilogram for the 28 PAHs. The 25 groups of alkylated PAHs are homologs of five groups of isomeric parent PAHs. Because of the lack of authentic standards, these homologs are reported semiquantitatively using a response factor from a parent PAH or a specific alkylated PAH. Precision data for the alkylated PAH homologs are presented using two different standard reference manuals produced by the National Institute of Standards and Technology: SRM 1941b and SRM 1944. The percent relative standard deviations for identified alkylated PAH homolog groups ranged from 1.55 to 6.98 for SRM 1941b and from 6.11 to 12.0 for SRM 1944. Homolog group concentrations reported under this method include the concentrations of individually identified compounds that are members of the group. Organochlorine (OC) pesticides--including toxaphene, polychlorinated biphenyls (PCBs), and organophosphate (OP) pesticides--can be isolated simultaneously using this method. In brief, sediment samples are centrifuged to remove excess water and extracted overnight with dichloromethan (95 percent) and methanol (5 percent). The extract is concentrated and then filtered through a 0.2-micrometer polytetrafluoroethylene syringe filter. The PAH fraction is isolated by quantitatively injecting an aliquot of sample onto two polystyrene-divinylbenzene gel-permeation chromatographic columns connected in series. The compounds are eluted with dichloromethane

  16. THE SPITZER SURVEY OF THE SMALL MAGELLANIC CLOUD (S{sup 3}MC): INSIGHTS INTO THE LIFE CYCLE OF POLYCYCLIC AROMATIC HYDROCARBONS

    SciTech Connect

    Sandstrom, Karin M.; Bolatto, Alberto D.; Draine, B. T.; Bot, Caroline; Stanimirovic, Snezana

    2010-06-01

    We present the results of modeling dust spectral energy distributions (SEDs) across the Small Magellanic Cloud (SMC) with the aim of mapping the distribution of polycyclic aromatic hydrocarbons (PAHs) in a low-metallicity environment. Using Spitzer Survey of the SMC photometry from 3.6 to 160 {mu}m over the main star-forming regions of the Wing and Bar of the SMC along with spectral mapping observations from 5 to 38 {mu}m from the Spitzer Spectroscopic Survey of the SMC in selected regions, we model the dust SED and emission spectrum to determine the fraction of dust in PAHs across the SMC. We use the regions of overlapping photometry and spectroscopy to test the reliability of the PAH fraction as determined from SED fits alone. The PAH fraction in the SMC is low compared to the Milky Way and variable-with relatively high fractions (q {sub PAH} {approx}1%-2%) in molecular clouds and low fractions in the diffuse interstellar medium (ISM; average (q {sub PAH}) = 0.6%). We use the map of PAH fraction across the SMC to test a number of ideas regarding the production, destruction, and processing of PAHs in the ISM. We find weak or no correlation between the PAH fraction and the distribution of carbon asymptotic giant branch stars, the location of supergiant H I shells and young supernova remnants, and the turbulent Mach number. We find that the PAH fraction is correlated with CO intensity, peaks in the dust surface density and the molecular gas surface density as determined from 160 {mu}m emission. The PAH fraction is high in regions of active star formation, as predicted by its correlation with molecular gas, but is suppressed in H II regions. Because the PAH fraction in the diffuse ISM is generally very low-in accordance with previous work on modeling the integrated SED of the SMC-and the PAH fraction is relatively high in molecular regions, we suggest that PAHs are destroyed in the diffuse ISM of the SMC and/or PAHs are forming in molecular clouds. We discuss the

  17. Evidence for pentagalloyl glucose binding to human salivary alpha-amylase through aromatic amino acid residues.

    PubMed

    Gyémánt, Gyöngyi; Zajácz, Agnes; Bécsi, Bálint; Ragunath, Chandran; Ramasubbu, Narayanan; Erdodi, Ferenc; Batta, Gyula; Kandra, Lili

    2009-02-01

    We demonstrate here that pentagalloyl glucose (PGG), a main component of gallotannins, was an effective inhibitor of HSA and it exerted similar inhibitory potency to Aleppo tannin used in this study. The inhibition of HSA by PGG was found to be non-competitive and inhibitory constants of K(EI)=2.6 microM and K(ESI)=3.9 microM were determined from Lineweaver-Burk secondary plots. PGG as a model compound for gallotannins was selected to study the inhibitory mechanism and to characterize the interaction of HSA with this type of molecules. Surface plasmon resonance (SPR) binding experiments confirmed the direct interaction of HSA and PGG, and it also established similar binding of Aleppo tannin to HSA. Saturation transfer difference (STD) experiment by NMR clearly demonstrated the aromatic rings of PGG may be involved in the interaction suggesting a possible stacking with the aromatic side chains of HSA. The role of aromatic amino acids of HSA in PGG binding was reinforced by kinetic studies with the W58L and Y151M mutants of HSA: the replacement of the active site aromatic amino acids with aliphatic ones decreased the PGG inhibition dramatically, which justified the importance of these residues in the interaction.

  18. Aliphatic polyester block polymers: renewable, degradable, and sustainable.

    PubMed

    Hillmyer, Marc A; Tolman, William B

    2014-08-19

    Nearly all polymers are derived from nonrenewable fossil resources, and their disposal at their end of use presents significant environmental problems. Nonetheless, polymers are ubiquitous, key components in myriad technologies and are simply indispensible for modern society. An important overarching goal in contemporary polymer research is to develop sustainable alternatives to "petro-polymers" that have competitive performance properties and price, are derived from renewable resources, and may be easily and safely recycled or degraded. Aliphatic polyesters are particularly attractive targets that may be prepared in highly controlled fashion by ring-opening polymerization of bioderived lactones. However, property profiles of polyesters derived from single monomers (homopolymers) can limit their applications, thus demanding alternative strategies. One such strategy is to link distinct polymeric segments in an A-B-A fashion, with A and B chosen to be thermodynamically incompatible so that they can self-organize on a nanometer-length scale and adopt morphologies that endow them with tunable properties. For example, such triblock copolymers can be useful as thermoplastic elastomers, in pressure sensitive adhesive formulations, and as toughening modifiers. Inspired by the tremendous utility of petroleum-derived styrenic triblock copolymers, we aimed to develop syntheses and understand the structure-property profiles of sustainable alternatives, focusing on all renewable and all readily degradable aliphatic polyester triblocks as targets. Building upon oxidation chemistry reported more than a century ago, a constituent of the peppermint plant, (-)-menthol, was converted to the ε-caprolactone derivative menthide. Using a diol initiator and controlled catalysis, menthide was polymerized to yield a low glass transition temperature telechelic polymer (PM) that was then further functionalized using the biomass-derived monomer lactide (LA) to yield fully renewable PLA

  19. Acid-base thermochemistry of gaseous aliphatic α-aminoacids.

    PubMed

    Bouchoux, Guy; Huang, Sihua; Inda, Bhawani Singh

    2011-01-14

    Acid-base thermochemistry of isolated aliphatic amino acids (denoted AAA): glycine, alanine, valine, leucine, isoleucine and proline has been examined theoretically by quantum chemical computations at the G3MP2B3 level. Conformational analysis on neutral, protonated and deprotonated species has been used to identify the lowest energy conformers and to estimate the population of conformers expected to be present at thermal equilibrium at 298 K. Comparison of the G3MP2B3 theoretical proton affinities, PA, and ΔH(acid) with experimental results is shown to be correct if experimental thermochemistry is re-evaluated and adapted to the most recent acidity-basicity scales. From this point of view, a set of evaluated proton affinities of 887, 902, 915, 916, 919 and 941 kJ mol(-1), and a set of evaluated ΔH(acid) of 1433, 1430, 1423, 1423, 1422 and 1426 kJ mol(-1), is proposed for glycine, alanine, valine, leucine, isoleucine and proline, respectively. Correlations with structural parameters (Taft's σ(α) polarizability parameter and molecular size) suggest that polarizability of the side chain is the major origin of the increase in PA and decrease in ΔH(acid) along the homologous series glycine, alanine, valine and leucine/isoleucine. Heats of formation of gaseous species AAA, AAAH(+) and [AAA-H](-) were computed at the G3MP2B3 level. The present study provides previously unavailable Δ(f)H°(298) for the ionized species AAAH(+) and [AAA-H](-). Comparison with Benson's estimate, and correlation with molecular size, show that several experimental Δ(f)H°(298) values of neutral or gaseous AAA might be erroneous.

  20. Pharmacological activities of cilantro's aliphatic aldehydes against Leishmania donovani.

    PubMed

    Donega, Mateus A; Mello, Simone C; Moraes, Rita M; Jain, Surendra K; Tekwani, Babu L; Cantrell, Charles L

    2014-12-01

    Leishmaniasis is a chronic infectious disease caused by different Leishmania species. Global occurrences of this disease are primarily limited to tropical and subtropical regions. Treatments are available; however, patients complain of side effects. Different species of plants have been screened as a potential source of new drugs against leishmaniasis. In this study, we investigated the antileishmanial activity of cilantro (Coriandrum sativum) essential oil and its main components: (E)-2-undecenal, (E)-2-decenal, (E)-2-dodecenal, decanal, dodecanal, and tetradecanal. The essential oil of C. sativum leaves inhibits growth of Leishmani donovani promastigotes in culture with an IC50 of 26.58 ± 6.11 µg/mL. The aliphatic aldehydes (E)-2-decenal (7.85 ± 0.28 µg/mL), (E)-2-undecenal (2.81 ± 0.21 µg/mL), and (E)-2-dodecenal (4.35 ± 0.15 µg/mL), all isolated from C. sativum essential oil, are effective inhibitors of in vitro cultures of L. donovani promastigotes. Aldehydes (E)-2-decenal, (E)-2-undecenal, and (E)-2-dodecenal were also evaluated against axenic amastigotes and IC50 values were determined to be 2.47 ± 0.25 µg/mL, 1.25 ± 0.11 µg/mL, and 4.78 ± 1.12 µg/mL, respectively. (E)-2-Undecenal and (E)-2-dodecenal demonstrated IC50 values of 5.65 ± 0.19 µg/mL and 9.60 ± 0.89 µg/mL, respectively, against macrophage amastigotes. These cilantro compounds showed no cytotoxicity against THP-1 macrophages.

  1. Separation and conductimetric detection of C1-C7 aliphatic monocarboxylic acids and C1-C7 aliphatic monoamines on unfunctionized polymethacrylate resin columns.

    PubMed

    Ohta, Kazutoku; Towata, Atsuya; Ohashi, Masayoshi; Takeuchi, Toyohide

    2004-06-11

    The application of unfunctionized polymethacrylate resin (TSKgel G3000PWXL) as a stationary phase in liquid chromatography with conductimetric detection for C1-C7 aliphatic monocarboxylic acids (formic acid, acetic acid, propionic acid, butyric acid, isovaleric acid, valeric acid, 3,3-dimethylbutyric acid, 4-methylvaleric acid, hexanoic acid, 2-methylhexanoic acid, 5-methylhexanoic acid and heptanoic acid) and C1-C7 aliphatic monoamines (methylamine, ethylamine, propylamine, isobutylamine, butylamine, isoamylamine, amylamine, 1,3-dimethylbutylamine, hexylamine, 2-heptylamine and heptylamine) was attempted with C8 aliphatic monocarboxylic acids (2-propylvaleric acid, 2-ethylhexanoic acid, 2-methylheptanoic acid and octanoic acid) and C8 aliphatic monoamines (1,5-dimethylhexylamine, 2-ethylhexylamine, 1-methylheptylamine and octylamine) as eluents, respectively. Using 1 mM 2-methylheptanoic acid at pH 4.0 as the eluent, excellent separation and relatively high sensitive detection for these C1-C7 carboxylic acids were achieved on a TSKgel G3000PWXL column (150 mm x 6 mm i.d.) in 60 min. Using 2 mM octylamine at pH 11.0 as the eluent, excellent separation and relatively high sensitive detection for these C1-C7 amines were also achieved on the TSKgel G3000PWXL column in 60 min.

  2. Colorless, Transparent, Aromatic Polyimide Films

    NASA Technical Reports Server (NTRS)

    St. Clair, A. K.; St. Clair, T. L.; Ezzell, K. S.; Ely, R. M.

    1986-01-01

    New process yields aromatic condensation polyimide films essentially colorless. Films between 90- and 100-percent transparent at visible wavelength of 500 nm. Optically transparent polyimide films made from variety of aromatic condensation polyimides. Range from very pale in color to colorless, compared to bright yellow color of conventional/ commercial aromatic polyimide film. Increased transparency achieved at no sacrifice in thermal stability, flexibility, toughness, or mechanical properties. These features extremely attractive as films or coating materials for aerospace applications or for any other applications where high optical transparency or thermal stability is required.

  3. Aromatic characterization of pot distilled kiwi spirits.

    PubMed

    López-Vázquez, Cristina; García-Llobodanin, Laura; Pérez-Correa, José Ricardo; López, Francisco; Blanco, Pilar; Orriols, Ignacio

    2012-03-07

    This study contributes fundamental knowledge that will help to develop a distillate of kiwi wine, made from kiwis of the Hayward variety grown in the southwest of Galicia (Spain). Two yeast strains, L1 (Saccharomyces cerevisiae ALB-6 from the EVEGA yeast collection) and L2 (S. cerevisiae Uvaferm BDX from Lallemand) were assessed to obtain a highly aromatic distillate. The kiwi spirits obtained were compared with other fruit spirits, in terms of higher alcohols, minor alcohols, monoterpenols, and other minor compounds, which are relevant in determining the quality and taste of the kiwi spirits. It was found that the kiwi juice fermented with yeast L1 produced a more aromatic distillate. In addition, kiwi distillates produced with both yeasts had the same ratio of trans-3-hexen-1-ol and cis-3-hexen-1-ol, which is lower than that found in other fruit distillates.

  4. Enantioselective aliphatic hydroxylations of racemic 1-hydroxy-3-methylcholanthrene by rat liver microsomes.

    PubMed

    Shou, M G; Yang, S K

    1990-01-01

    Enantiomeric pairs of 1-hydroxy-3-hydroxymethylcholanthrene (1-OH-3-OHMC), 3-methylcholanthrene (3MC) trans- and cis-1,2-diols, and 1-hydroxy-3-methylcholanthrene (1-OH-3MC) were resolved by HPLC using a covalently bonded (R)-N-(3,5-dinitrobenzoyl)phenylglycine chiral stationary phase (Pirkle type 1A) column. The absolute configuration of an enantiomeric 3MC trans-1,2-diol was established by the exciton chirality CD method following conversion to a bis-p-N,N-dimethylaminobenzoate. Incubation of an enantiomeric 1-OH-3MC with rat liver microsomes resulted in the formation of enantiomeric 3MC trans- and cis-1,2-diols; the absolute configurations of the enantiomeric 1-OH-3MC and 3MC cis-1,2-diol were established on the basis of the absolute configuration of an enantiomeric 3MC trans-1,2-diol. Absolute configurations of enantiomeric 1-OH-3-OHMC were determined by comparing their CD spectra with those of enantiomeric 1-OH-3MC. The relative amount of three aliphatic hydroxylation products formed by rat liver microsomal metabolism of racemic 1-OH-3MC was 1-OH-3-OHMC greater than 3MC cis-1,2-diol greater than 3MC trans-1,2-diol. Enzymatic hydroxylation at C2 of racemic 1-OH-3MC was enantioselective toward the 1S-enantiomer over the 1R-enantiomer (approximately 3/1); hydroxylation at the C3-methyl group was enantioselective toward the 1R-enantiomer over the 1S-enantiomer (approximately 58/42). Rat liver microsomal C2-hydroxylation of racemic 1-OH-3MC resulted in a 3MC trans-1,2-diol with a (1S,2S)/(1R,2R) ratio of 63/37 and a 3MC cis-1,2-diol with a (1S,2R)/(1R,2S) ratio of 12/88, respectively.

  5. Spider monkeys (Ateles geoffroyi) are less sensitive to the odor of aliphatic ketones than to the odor of other classes of aliphatic compounds.

    PubMed

    Eliasson, Moa; Hernandez Salazar, Laura Teresa; Laska, Matthias

    2015-10-01

    Aliphatic ketones are widely present in body-borne and food odors of primates. Therefore, we used an operant conditioning paradigm and determined olfactory detection thresholds in four spider monkeys for a homologous series of aliphatic 2-ketones (2-butanone to 2-nonanone) and two of their isomers (3- and 4-heptanone). We found that, with the exception of the two shortest-chained ketones, all animals detected concentrations <1 ppm (parts per million), and with five odorants individual animals even reached threshold values <0.1 ppm. Further, we found a significant correlation between olfactory sensitivity of the spider monkeys and carbon chain length of the 2-ketones which can best be described as a U-shaped function. In contrast, no significant correlation was found between olfactory sensitivity and position of the functional carbonyl group. Across-odorant and across-species comparisons revealed the following: spider monkeys are significantly less sensitive to the odors of aliphatic ketones than to the odor of other classes of aliphatic compounds (1-alcohols, n-aldehydes, n-acetic esters, and n-carboxylic acids) sharing the same carbon length. Spider monkeys do not differ significantly in their olfactory sensitivity for aliphatic ketones from squirrel monkeys and pigtail macaques, but are significantly less sensitive to these odorants compared to human subjects and mice. These findings support the notion that neuroanatomical and genetic properties do not allow for reliable predictions with regard to a species' olfactory sensitivity. Further, we conclude that the frequency of occurrence of a class of odorants in a species' chemical environment does not allow for reliable predictions of the species' olfactory sensitivity.

  6. The human ether-a'-go-go related gene (hERG) K+ channel blockade by the investigative selective-serotonin reuptake inhibitor CONA-437: limited dependence on S6 aromatic residues.

    PubMed

    Alexandrou, A J; Milnes, J T; Sun, S Z; Fermini, B; Kim, S C; Jenkinson, S; Leishman, D J; Witchel, H J; Hancox, J C; Leaney, J L

    2014-08-01

    Diverse non-cardiac drugs adversely influence cardiac electrophysiology by inhibiting repolarising K(+) currents mediated by channels encoded by the human ether-a-go-go-related gene (hERG). In this study, pharmacological blockade of hERG K(+) channel current (I(hERG)) by a novel investigative serotonin-selective reuptake inhibitor (SSRI), CONA-437, was investigated. Whole-cell patch-clamp measurements of I(hERG) were made from human embryonic kidney (HEK 293) cells expressing wild-type (WT) or mutant forms of the hERG channel. With a step-ramp voltage-command, peak I(hERG) was inhibited with an IC(50) of 1.34 μM at 35 ±1°C; the IC(50) with the same protocol was not significantly different at room temperature. Voltage-command waveform selection had only a modest effect on the potency of I(hERG) block: the IC50 with a ventricular action potential command was 0.72 μM. I(hERG) blockade developed rapidly with time following membrane depolarisation and showed a weak dependence on voltage, accompanied by a shift of ≈ -5 mV in voltage-dependence of activation. There was no significant effect of CONA-437 on voltage-dependence of I(hERG) inactivation, though at some voltages an apparent acceleration of the time-course of inactivation was observed. Significantly, mutation of the S6 aromatic amino acid residues Y652 and F656 had only a modest effect on I(hERG) blockade by CONA-437 (a 3-4 fold shift in affinity). CONA-437 at up to 30 μM had no significant effect on either Nav1.5 sodium channels or L-type calcium channels. In conclusion, the novel SSRI CONA-437 is particularly notable as a gating-dependent hERG channel inhibitor for which neither S6 aromatic amino-acid constituent of the canonical drug binding site on the hERG channel appears obligatory for I(hERG) inhibition to occur.

  7. Three-dimensional aromatic networks.

    PubMed

    Toyota, Shinji; Iwanaga, Tetsuo

    2014-01-01

    Three-dimensional (3D) networks consisting of aromatic units and linkers are reviewed from various aspects. To understand principles for the construction of such compounds, we generalize the roles of building units, the synthetic approaches, and the classification of networks. As fundamental compounds, cyclophanes with large aromatic units and aromatic macrocycles with linear acetylene linkers are highlighted in terms of transannular interactions between aromatic units, conformational preference, and resolution of chiral derivatives. Polycyclic cage compounds are constructed from building units by linkages via covalent bonds, metal-coordination bonds, or hydrogen bonds. Large cage networks often include a wide range of guest species in their cavity to afford novel inclusion compounds. Topological isomers consisting of two or more macrocycles are formed by cyclization of preorganized species. Some complicated topological networks are constructed by self-assembly of simple building units.

  8. Bioassay of polycyclic aromatic hydrocarbons

    SciTech Connect

    Van Kirk, E.A.

    1980-08-01

    A positive relationship was found between the photodynamic activity of 24 polycyclic aromatic hydrocarbons versus published results on the mutagenicity, carcinogenicity, and initiation of unscheduled DNA synthesis. Metabolic activation of benzo(a)pyrene resulted in detection of increased mutagenesis in Paramecium tetraurelia as found also in the Ames Salmonella assay. The utility of P. tetraurelia as a biological detector of hazardous polycyclic aromatic hydrocarbons is discussed.

  9. Polyphenylquinoxalines via aromatic nucleophilic displacement

    NASA Technical Reports Server (NTRS)

    Hergenrother, Paul M. (Inventor); Connell, John W. (Inventor)

    1990-01-01

    Polyphenylquinoxalines are prepared by the nucleophilic displacement reaction of di(hydroxyphenyl)quinoxaline monomers with activated aromatic dihalides or dinitro compounds. The reactions are carried out in polar aprotic solvents using alkali metal bases at elevated temperatures under nitrogen. The di(hydroxyphenyl)quinoxaline monomers are prepared either by reacting stoichiometric quantities of aromatic bis(o-diamines) with a hydroxybenzil or by reacting o-phenylenediamine with a dihydroxybenzil or bis(hydroxyphenylglyoxylyl)benzene.

  10. Polyphenylquinoxalines via aromatic nucleophilic displacement

    NASA Technical Reports Server (NTRS)

    Hergenrother, Paul M. (Inventor); Connell, John W. (Inventor)

    1991-01-01

    Polyphenylquinoxalines are prepared by the nucleophilic displacement reaction of di(hydroxyphenyl)quinoxaline monomers with activated aromatic dihalides or dinitro compounds. The reactions are carried out in polar aprotic solvents during alkali metal bases at elevated temperatures under nitrogen. The di(hydroxyphenyl)quinoxaline monomers are prepared either by reacting stoichiometric quantities of aromatic bis(o-diamines) with a hydroxybenzil or by reacting o-phenylenediamine with a dihydroxybenzil or bis(hydroxyphenylglyoxylyl)benzene.

  11. Oral vaccination of calves with an aromatic-dependent Salmonella dublin (O9,12) hybrid expressing O4,12 protects against S. dublin (O9,12) but not against Salmonella typhimurium (O4,5,12).

    PubMed Central

    Segall, T; Lindberg, A A

    1993-01-01

    Three groups of six calves each, 5 to 7 weeks old, were orally vaccinated with the live aromatic-dependent delta aroA Salmonella dublin (O9,12) hybrid strain SL7103 with the O4,12-specifying rfb gene cluster from Salmonella typhimurium. SL7103 was given in three weekly doses, increasing from 2 x 10(9) to 1 x 10(11) bacteria per ml, was well tolerated, and caused mild, short-term temperature increases which diminished with each immunization. The strain was shed for up to 1 week. Strain SL7103 elicited significant (P < 0.001) and equal anti-S. dublin and -S. typhimurium lipopolysaccharide serum antibody responses and skin delayed-type hypersensitivity immune responses. Six vaccinated calves orally challenged with 10(10) CFU (equivalent to 1,000 50% lethal doses) of the virulent parent strain S. dublin SVA47 were protected and experienced only transient fever and mild mucoid diarrhea. However, six vaccinated calves orally challenged with 3 x 10(9) CFU and another six challenged with 3 x 10(8) CFU (equivalent to 1,000 50% lethal doses) of the virulent S. typhimurium SVA44 became bacteremic with a profuse hemorrhagic diarrhea and had to be sacrificed within 2 to 7 days. The results suggest that the S. typhimurium antilipopolysaccharide immunity was insufficient to provide a solid protective efficacy against oral S. typhimurium infection. The immunohistopathological examination revealed that S. typhimurium SVA44 could be found in all layers of the intestinal mucosa and the lymphatic tissues of the Peyer's patches. In contrast, S. dublin SVA47 was found predominantly in the columnar enterocytes of the jejunum and ileum and the follicle-associated epithelium over the Peyer's patches. In addition, SVA47 was found in the glandular tissues of the duodenal and tonsillar areas and in the lungs. This suggests that the S. typhimurium and S. dublin strains have different virulence traits determining their tissue localization and dissemination. Images PMID:7681042

  12. Simultaneous and sensitive analysis of aliphatic carboxylic acids by ion-chromatography using on-line complexation with copper(II) ion.

    PubMed

    Kemmei, Tomoko; Kodama, Shuji; Yamamoto, Atsushi; Inoue, Yoshinori; Hayakawa, Kazuichi

    2015-01-02

    A new approach to ion chromatography is proposed to improve the UV detection of aliphatic carboxylic acids separated by anion-exchange chromatography. When copper(II) ion added to the mobile phase, it forms complexes with carboxylic acids that can be detected at 240 nm. The absorbance was found to increase with increasing copper(II) ion concentration. The retention times of α-hydroxy acids were also found to depend on the copper(II) ion concentration. Addition of acetonitrile to the mobile phase improved the separation of aliphatic carboxylic acids. The detection limits of the examined carboxylic acids (formate, glycolate, acetate, lactate, propionate, 3-hydroxypropionate, n-butyrate, isobutyrate, n-valerate, isovalerate, n-caproate) calculated at S/N=3 ranged from 0.06 to 3 μM. The detector signal was linear over three orders of magnitude of carboxylic acid concentration. The proposed method was successfully applied to analyze aliphatic carboxylic acids in rainwater and bread.

  13. A convenient and validated enantiomer separation of chiral aliphatic amines as nitrobenzoxadiazole derivatives on polysaccharide-derived chiral stationary phases under simultaneous ultraviolet and fluorescence detection.

    PubMed

    Adhikari, Suraj; Kang, Jong Seong; Lee, Wonjae

    2016-12-01

    A convenient method using a fluorogenic agent, 4-chloro-7-nitro-1,2,3-benzoxadiazole (NBD-Cl), was developed for enantiomer separation of chiral aliphatic amines including amino alcohols by normal high-performance liquid chromatography. The enantiomer separation of chiral aliphatic amines as NBD derivatives was performed on six covalently bonded and four coated-type polysaccharide-derived chiral stationary phases (CSPs) under simultaneous ultraviolet (UV) and fluorescence detection (FLD). Among the covalently bonded CSPs, Chiralpak IE showed the best enantiomer separation for most analytes. The other CSPs also showed good enantioselectivity except for Chiralpak IB. On the other hand, Chiralpak AD-H and Amylose-1 generally exhibited better enantiomer separation of NBD derivatized chiral amines among the coated CSPs. The developed analytical technique was also applied to determine the optical purity of commercially available (R)- and (S)-leucinol; the impurity was found to be 0.06%. The developed method was validated and proved to be an accurate, precise, sensitive, and selective method suitable for separation of chiral aliphatic amines as NBD derivatives under simultaneous UV and FLD.

  14. Cooperation and competition between halogen bonding and van der Waals forces in supramolecular engineering at the aliphatic hydrocarbon/graphite interface: position and number of bromine group effects.

    PubMed

    Zha, Bao; Dong, Meiqiu; Miao, Xinrui; Peng, Shan; Wu, Yican; Miao, Kai; Hu, Yi; Deng, Wenli

    2017-01-07

    Herein, the photophysical properties of two π-conjugated thienophenanthrene derivatives (6,9- and 5,10-DBTD) are reported. Their self-assembled monolayers in aliphatic hydrocarbon solvents under different concentrations were investigated by scanning tunneling microscopy on a graphite surface. The STM results revealed that the self-assembled structures of the two geometrical isomers exhibited absolutely different behaviors. At the aliphatic solvent/graphite interface, 6,9-DBTD produced almost a single stable coassembled linear structure, except for that with n-tridecane as the solvent. However, the self-assembly of 5,10-DBTD showed structural diversity, and it presented a gradient variety through increasing the chain length of the aliphatic solvents as well as the solution concentration. All ordered self-assembled adlayers critically depend on not only the interchain van der Waals (vdW) interactions, but also on multiple intermolecular interactions, including BrO[double bond, length as m-dash]C and BrS hetero-halogen bonds, homo-BrBr interactions, and HBr and HO hydrogen bonds. We proposed that the cooperation and competition of the intermolecular interactions involving a Br atom and interchain vdW forces induce this structural variety. Density functional theory calculations support to unravel the different elementary structural units based on halogen bonds and hydrogen bonds and were useful tools to dissect and explain the formation mechanism.

  15. Polycyclic Aromatic Hydrocarbons

    NASA Technical Reports Server (NTRS)

    Salama, Farid

    2010-01-01

    Carbonaceous materials play an important role in space. Polycyclic Aromatic Hydrocarbons (PAHs) are a ubiquitous component of the carbonaceous materials. PAHs are the best-known candidates to account for the IR emission bands. They are also thought to be among the carriers of the diffuse interstellar absorption bands (DIBs). PAH ionization states reflect the ionization balance of the medium while PAH size, composition, and structure reflect the energetic and chemical history of the medium. A major challenge is to reproduce in the laboratory the physical conditions that exist in the emission and absorption interstellar zones. The harsh physical conditions of the ISM -low temperature, collisionless, strong UV radiation fields- are simulated in the laboratory by associating a molecular beam with an ionizing discharge to generate a cold plasma expansion. PAH ions and radicals are formed from the neutral precursors in an isolated environment at low temperature and probed with high-sensitivity cavity ringdown spectroscopy in the NUV-NIR range. Carbon nanoparticles are also formed during the short residence time of the precursors in the plasma and are characterized with time-offlight mass spectrometry. These experiments provide unique information on the spectra of large carbonaceous molecules and ions in the gas phase that can now be directly compared to interstellar and circumstellar observations (IR emission bands, DIBs, extinction curve). These findings also hold great potential for understanding the formation process of interstellar carbonaceous grains. We will review recent progress in the experimental and theoretical studies of PAHs, compare the laboratory data with astronomical observations and discuss the global implications.

  16. Manganese-catalyzed late-stage aliphatic C-H azidation.

    PubMed

    Huang, Xiongyi; Bergsten, Tova M; Groves, John T

    2015-04-29

    We report a manganese-catalyzed aliphatic C-H azidation reaction that can efficiently convert secondary, tertiary, and benzylic C-H bonds to the corresponding azides. The method utilizes aqueous sodium azide solution as the azide source and can be performed under air. Besides its operational simplicity, the potential of this method for late-stage functionalization has been demonstrated by successful azidation of various bioactive molecules with yields up to 74%, including the important drugs pregabalin, memantine, and the antimalarial artemisinin. Azidation of celestolide with a chiral manganese salen catalyst afforded the azide product in 70% ee, representing a Mn-catalyzed enantioselective aliphatic C-H azidation reaction. Considering the versatile roles of organic azides in modern chemistry and the ubiquity of aliphatic C-H bonds in organic molecules, we envision that this Mn-azidation method will find wide application in organic synthesis, drug discovery, and chemical biology.

  17. Seasonal distribution of aliphatic hydrocarbons in the Vaza Barris Estuarine System, Sergipe, Brazil.

    PubMed

    Barbosa, José Carlos S; Santos, Lukas G G V; Sant'Anna, Mércia V S; Souza, Michel R R; Damasceno, Flaviana C; Alexandre, Marcelo R

    2016-03-15

    The seasonal assessment of anthropogenic activities in the Vaza Barris estuarine river system, located in the Sergipe state, northeastern Brazil, was performed using the aliphatic hydrocarbon distribution. The aliphatic hydrocarbon and isoprenoid (Pristane and Phytane) concentrations ranged between 0.19 μg g(-1) and 8.5 μg g(-1) of dry weight. Data were analyzed using Kruskal-Wallis test, with significance level set at p<0.05, and no seasonality distribution change was observed. The Carbon Preference Index (CPI), associated with n-alkanes/n-C16, Low Molecular Weight/High Molecular Weight ratio (LMW/HMW) and Terrigenous to Aquatic Ratio (TAR) suggested biogenic input of aliphatic hydrocarbons for most samples, with significant contribution of higher plants.

  18. Analysis of dechlorination kinetics of chlorinated aliphatic hydrocarbons by Fe(II) in cement slurries.

    PubMed

    Jung, Bahngmi; Batchelor, Bill

    2008-03-21

    Degradative solidification/stabilization with ferrous iron (DS/S-Fe(II)) has been found to be effective in degrading a number of chlorinated aliphatic hydrocarbons including 1,1,1-trichloroethane (1,1,1-TCA), 1,1,2,2-tetrachloroethane (1,1,2,2-TeCA), tetrachloroethylene (PCE), trichloroethylene (TCE), 1,1-dichloroethylene (1,1-DCE), vinyl chloride (VC), carbon tetrachloride (CT) and chloroform (CF). Previous studies have characterized degradation kinetics in DS/S-Fe(II) systems as affected by Fe(II) dose, pH and initial target organic concentration. The goal of this study is to investigate the importance of various chemical properties on degradation kinetics of DS/S-Fe(II). This was accomplished by first measuring rate constants for degradation of 1,1,1-TCA, 1,1,2,2-TeCA and 1,2-dichloroethane (1,2-DCA) in individual batch experiments. Rate constants developed in these experiments and those obtained from the literature were related to thermodynamic parameters including one-electron reduction potential, two-electron reduction potential, bond dissociation energy and lowest unoccupied molecular orbital energies. Degradation kinetics by Fe(II) in cement slurries were generally represented by a pseudo-first-order rate law. The results showed that the rate constants for chlorinated methanes (e.g. CT, CF) and chlorinated ethanes (e.g. 1,1,1-TCA) were higher than those for chlorinated ethylenes (e.g. PCE, TCE, 1,1-DCE and VC) under similar experimental conditions. The log of the pseudo-first-order rate constant (k) was found to correlate better with lowest unoccupied molecular orbital energies (E(LUMO)) (R2=0.874) than with other thermodynamic parameter descriptors.

  19. Gas phase enantiomeric distinction of (R)- and (S)-aromatic hydroxy esters by negative ion chemical ionization mass spectrometry using a chiral reagent gas

    NASA Astrophysics Data System (ADS)

    Mancel, Valérie; Sellier, Nicole; Lesage, Denis; Fournier, Françoise; Tabet, Jean-Claude

    2004-10-01

    Negative ion chemical ionization (NICI) using a chiral reagent gas such as (2S,3S) butanediol (GSS) allows the differentiation of chiral [alpha] hydroxy esters (MR or MS). The distinction is significantly enhanced by using CID on the deprotonated hetero dimer [M + (GSS-H)]-. The contribution of a non covalent [M + (GSS-H)]- competitive form is very minor. In fact, a covalent form appears favored. To produce a covalent adduct ion, an enantioselectivity of the alkoxide attack on the electrophilic ester site to form a tetravalent adduct is suggested by the product ion abundances. This observed steric control is consistent with the one observed in solution (Cram-Felkin addition/reduction orientation). The dissociations under collision conditions of the product deprotonated diastereomeric compounds show a stereospecific effect in the elimination of alcohol from the tetravalent adduct ions rather than a regeneration of the deprotonated diol reagent as expected from non-covalent heterodimer. This study shows an orientation with a chiral compound that allows, from an analytical point of view, the distinction of enantiomers and the attribution of chirality in the gas phase under NICI conditions.

  20. Bacterial degradation of monocyclic aromatic amines.

    PubMed

    Arora, Pankaj K

    2015-01-01

    Aromatic amines are an important group of industrial chemicals, which are widely used for manufacturing of dyes, pesticides, drugs, pigments, and other industrial products. These compounds have been considered highly toxic to human beings due to their carcinogenic nature. Three groups of aromatic amines have been recognized: monocyclic, polycyclic, and heterocyclic aromatic amines. Bacterial degradation of several monocyclic aromatic amines has been studied in a variety of bacteria, which utilizes monocyclic aromatic amines as their sole source of carbon and energy. Several degradation pathways have been proposed and the related enzymes and genes have also been characterized. Many reviews have been reviewed toxicity of monocyclic aromatic amines; however, there is lack of review on biodegradation of monocyclic aromatic amines. The aim of this review is to summarize bacterial degradation of monocyclic aromatic amines. This review will increase our current understanding of biochemical and molecular basis of bacterial degradation of monocyclic aromatic amines.

  1. An Iminium Salt Organocatalyst for Selective Aliphatic C-H Hydroxylation.

    PubMed

    Wang, Daoyong; Shuler, William G; Pierce, Conor J; Hilinski, Michael K

    2016-08-05

    The first examples of catalysis of aliphatic C-H hydroxylation by an iminium salt are presented. The method allows the selective organocatalytic hydroxylation of unactivated 3° C-H bonds at room temperature using hydrogen peroxide as the terminal oxidant. Hydroxylation of an unactivated 2° C-H bond is also demonstrated. Furthermore, improved functional group compatibility over other catalytic methods is reported in the form of selectivity for aliphatic C-H hydroxylation over alcohol oxidation. On the basis of initial mechanistic studies, an oxaziridinium species is proposed as the active oxidant.

  2. Iron-Catalyzed Decarboxylative Alkyl Etherification of Vinylarenes with Aliphatic Acids as the Alkyl Source.

    PubMed

    Jian, Wujun; Ge, Liang; Jiao, Yihang; Qian, Bo; Bao, Hongli

    2017-03-20

    Because of the lack of effective alkylating reagents, alkyl etherification of olefins with general alkyl groups has not been previously reported. In this work, a variety of alkyl diacyl peroxides and peresters generated from aliphatic acids have been found to enable the first iron-catalyzed alkyl etherification of olefins with general alkyl groups. Primary, secondary and tertiary aliphatic acids are suitable for this reaction, delivering products with yields up to 97 %. Primary and secondary alcohols react well, affording products in up to 91 % yield.

  3. Carbon and Hydrogen Stable Isotope Fractionation Associated with the Aerobic and Anaerobic Degradation of Saturated and Alkylated Aromatic Hydrocarbons.

    PubMed

    Musat, Florin; Vogt, Carsten; Richnow, Hans H

    2016-01-01

    Saturated hydrocarbons (alkanes) and alkylated aromatic hydrocarbons are abundant environmental compounds. Hydrocarbons are primarily removed from the environment by biodegradation, a process usually associated with moderate carbon and significant hydrogen isotope fractionation allowing monitoring of biodegradation processes in the environment. Here, we review the carbon and hydrogen stable isotope fractionation associated with the cleavage of C-H bonds at alkyl chains of hydrocarbons. Propane, n-butane and ethylbenzene were used as model components for alkyl moieties of aliphatic and aromatic hydrocarbons with emphasis on the cleavage of the C-H bond without the involvement of molecular oxygen. The carbon and hydrogen isotope fractionation factors were further used to explore the diagnostic potential for characterizing the mode of bond cleavage under oxic and anoxic conditions. x039B; factors, calculated to correlate carbon and hydrogen fractionation, allowed to distinguish between aerobic and anaerobic biodegradation processes in the environment.

  4. Aromatic-Aromatic Interactions in Biological System: Structure Activity Relationships

    SciTech Connect

    Rajagopal, Appavu; Deepa, Mohan; Govindaraju, Munisamy

    2016-02-26

    While, intramolecular hydrogen bonds have attracted the greatest attention in studies of peptide conformations, the recognition that several other weakly polar interactions may be important determinants of folded structure has been growing. Burley and Petsko provided a comprehensive overview of the importance of weakly polar interactions, in shaping protein structures. The interactions between aromatic rings, which are spatially approximate, have attracted special attention. A survey of the proximal aromatic residue pairs in proteins, allowed Burley and Petsko to suggest that, “phenyl ring centroids are separated by a preferential distance of between 4.5 and 7 Å, and dihedral angles approximately 90° are most common”.

  5. 40 CFR 721.10188 - Fatty acids, tall-oil, reaction products with 4-methyl-2-pentanone and aliphatic polyamine...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Fatty acids, tall-oil, reaction... Fatty acids, tall-oil, reaction products with 4-methyl-2-pentanone and aliphatic polyamine (generic). (a... generically as fatty acids, tall-oil, reaction products with 4-methyl-2-pentanone and aliphatic polyamine...

  6. 40 CFR 721.10188 - Fatty acids, tall-oil, reaction products with 4-methyl-2-pentanone and aliphatic polyamine...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Fatty acids, tall-oil, reaction... Fatty acids, tall-oil, reaction products with 4-methyl-2-pentanone and aliphatic polyamine (generic). (a... generically as fatty acids, tall-oil, reaction products with 4-methyl-2-pentanone and aliphatic polyamine...

  7. 40 CFR 721.10190 - Formaldehyde, polymer with aliphatic diamine and phenol, reaction products with 4-methyl-2...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... diamine and phenol, reaction products with 4-methyl-2-pentanone (generic). 721.10190 Section 721.10190... Formaldehyde, polymer with aliphatic diamine and phenol, reaction products with 4-methyl-2-pentanone (generic... identified generically as formaldehyde, polymer with aliphatic diamine and phenol, reaction products with...

  8. 40 CFR 721.10188 - Fatty acids, tall-oil, reaction products with 4-methyl-2-pentanone and aliphatic polyamine...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Fatty acids, tall-oil, reaction... Fatty acids, tall-oil, reaction products with 4-methyl-2-pentanone and aliphatic polyamine (generic). (a... generically as fatty acids, tall-oil, reaction products with 4-methyl-2-pentanone and aliphatic polyamine...

  9. 40 CFR 721.10188 - Fatty acids, tall-oil, reaction products with 4-methyl-2-pentanone and aliphatic polyamine...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Fatty acids, tall-oil, reaction... Fatty acids, tall-oil, reaction products with 4-methyl-2-pentanone and aliphatic polyamine (generic). (a... generically as fatty acids, tall-oil, reaction products with 4-methyl-2-pentanone and aliphatic polyamine...

  10. 40 CFR 721.10188 - Fatty acids, tall-oil, reaction products with 4-methyl-2-pentanone and aliphatic polyamine...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Fatty acids, tall-oil, reaction... Fatty acids, tall-oil, reaction products with 4-methyl-2-pentanone and aliphatic polyamine (generic). (a... generically as fatty acids, tall-oil, reaction products with 4-methyl-2-pentanone and aliphatic polyamine...

  11. 40 CFR 721.10190 - Formaldehyde, polymer with aliphatic diamine and phenol, reaction products with 4-methyl-2...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... diamine and phenol, reaction products with 4-methyl-2-pentanone (generic). 721.10190 Section 721.10190... Formaldehyde, polymer with aliphatic diamine and phenol, reaction products with 4-methyl-2-pentanone (generic... identified generically as formaldehyde, polymer with aliphatic diamine and phenol, reaction products with...

  12. 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.

  13. Aliphatic side chains of proteins as potential geomarkers of NOM liberated from the melting permafrost and discharged to the Arctic Ocean by the Kolyma River run off

    NASA Astrophysics Data System (ADS)

    Dubinenkov, I. V.; Perminova, I.; Kononikhin, A.; Nikolaev, E.; Hertkorn, N.; Bulygina, E. B.; Holmes, R. M.

    2011-12-01

    The Arctic ecosystem is highly sensitive to climate change. Global warming might have considerable effects on regional carbon cycling due to permafrost melting. Permafrost in the Arctic region represents an extremely large organic carbon reservoir mostly stored in the permafrost. Mobilization of just a small portion of carbon stored in Arctic soils will have considerable impacts on the flux of organic carbon from land to the Arctic Ocean, which can affect the Arctic environment. The Kolyma River watershed is one of the Arctic Ocean's largest. It is dominated by continuous permafrost which is underlain with rich organic soils susceptible to increased fluvial transport. The goal of the work was to analyze the structure of isolated natural organic matter from different fresh water environments of the Kolyma river basin. NOM was isolated from the Kolyma River main stream, its tributaries, a thermokarst lake, a floodplain stream and the permafrost. Solid phase extraction technique was used with Bond Elute PPL cartridges. Nuclear magnetic resonance spectroscopy (NMR) and Fourier Transform Ion Cyclotron Resonance Mass Spectroscopy (FTICRMS) was used for structural studies because of unsurpassed molecular level structural information provided by these high resolution magnetic resonance techniques. The NOM samples from the Kolyma River showed high contents of non-substituted aliphatic structures with a low content of aromatics and carbohydrates. Aliphatic nature may indicate a microbial source of NOM in the form of degraded terpenoids and hopanols. It was shown that almost all NOM samples from the rivers had similar molecular composition enriched with aliphatic units. The samples from permafrost mud streams were significantly different and contained sharp peptide signatures. In general, permafrost NOM contained much less degraded peptide residuest as compared to riverine samples. Identification of these residues showed the presence of branched amino acids (valine, alanine

  14. 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.

  15. 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.

  16. The macromolecular aromatic domain in suberized tissue: a changing paradigm

    NASA Technical Reports Server (NTRS)

    Bernards, M. A.; Lewis, N. G.

    1998-01-01

    As a structural feature of specialized cell walls, suberization remains an enigma, despite its obvious importance both during normal growth and development and as a stress response in plants. While it is clear that suberized tissues contain both polyaromatic and polyaliphatic domains, and that each of these has its own unique characteristics, whether there is a contiguous macromolecule that can be called suberin is an open question. From a structural perspective, the aromatic domain is unique and distinct from lignin, and is apparently comprised primarily of (poly)hydroxycinnamates, such as amides (e.g., feruloyltyramine). The aliphatic domain is also unique, being quite distinct from cutin in terms of both its chemical composition and cellular location. In the present paper, histochemical, structural and biochemical data, particularly, regarding the polyaromatic domain of suberized tissues, are critically reviewed. A revised description of the polyaromatic domain of suberized tissues, based on the consensus that is emerging from the current data, is presented and especially includes a spatially distinct (poly)hydroxycinnamoyl-containing macromolecule.

  17. Polyphenylquinoxalines via Aromatic Nucleophilic Displacement

    NASA Technical Reports Server (NTRS)

    Hergenrother, Paul M.; Connell, John W.

    1988-01-01

    Polyphenylquinoxalines are produced by an aromatic nucleophilic displacement reaction involving an activated aromatic dihalide with an appropriate quinoxaline monomer. Polyphenylquinoxalines are high temperature thermoplastics used as adhesives, coatings, films and composite matrices. The novelty of this invention is threefold: (1) some of the quinoxaline monomers are new compositions of matter; (2) the phenylquinoxaline polymers which are the end products of the invention are new compositions of matter; and (3) the method of forming the polymers is novel, replacing a more costly prior art process, which is also limited in the kinds of products prepared therefrom.

  18. Poly(N-arylenbenzimidazoles) via aromatic nucleophilic displacement

    NASA Technical Reports Server (NTRS)

    Connell, John W. (Inventor); Hergenrother, Paul M. (Inventor); Smith, Joseph G., Jr. (Inventor)

    1995-01-01

    Novel poly(N-arylenebenzimidazole)s (PNABIs) are prepared by the aromatic nucleophilic displacement reaction of novel di(hydroxyphenyl-N-arylene benzimidazole) monomers with activated aromatic dihalides or activated aromatic dinitro compounds. The polymerizations are carried out in polar aprotic solvents such as N-methyl-2-pyrrolidinone or N,N-dimethylacetamide using alkali metal bases such as potassium carbonate at elevated temperatures under nitrogen. The di(hydroxyphenyl N-arylenebenzimidazole) monomers are synthesized by reacting phenyl 4-hydroxybenzoate with bis(2-aminoanilino) arylenes in diphenylsulfone. Moderate molecular weight PNABIs of new chemical structures were prepared that exhibit a favorable combination of physical and mechanical properties. The use of the novel di(hydroxyphenyl N-arylenebenzimidazole)s permits a more economical and easier way to prepare PNABIs than previous routes.

  19. No-carrier-added (NCA) aryl ([sup 18]F) fluorides via the nucleophilic aromatic substitution of electron rich aromatic rings

    DOEpatents

    Yushin Ding; Fowler, J.S.; Wolf, A.P.

    1993-10-19

    A method for synthesizing no-carrier-added (NCA) aryl [.sup.18 F] fluoride substituted aromatic aldehyde compositions bearing an electron donating group is described. The method of the present invention includes the step of reacting aromatic nitro aldehydes having a suitably protected hydroxyl substitutent on an electron rich ring. The reaction is The U.S. Government has rights in this invention pursuant to Contract Number DE-AC02-76CH00016, between the U.S. Department of Energy and Associated Universities Inc.

  20. No-carrier-added (NCA) aryl (18E) fluorides via the nucleophilic aromatic substitution of electron rich aromatic rings

    DOEpatents

    Ding, Yu-Shin; Fowler, Joanna S.; Wolf, Alfred P.

    1993-01-01

    A method for synthesizing no-carrier-added (NCA) aryl [.sup.18 F] fluoride substituted aromatic aldehyde compositions bearing an electron donating group is described. The method of the present invention includes the step of reacting aromatic nitro aldehydes having a suitably protected hydroxyl substitutent on an electron rich ring. The reaction is The U.S. Government has rights in this invention pursuant to Contract Number DE-AC02-76CH00016, between the U.S. Department of Energy and Associated Universities Inc.

  1. A review of exposure conditions and possible health effects associated with aerosol and vapour from low-aromatic oil-based drilling fluids.

    PubMed

    Eide, I

    1990-04-01

    This paper reviews investigations on possible health effects after inhalation of aerosol and vapour from the low-aromatic oil-based drilling fluids which have replaced the diesel-based fluids. The main advantage of the low-aromatic base oils with respect to health hazard is their lower volatility. However, some aliphatic and naphthenic hydrocarbons are distributed more efficiently to the brain than are the corresponding aromatic ones. Reducing the content of aromatic hydrocarbons becomes particularly important when the upper end of the boiling point range is sufficiently high for the base oil to contain carcinogenic polycyclic aromatic hydrocarbons (PAH). As a result of enclosure and local extract ventilation it has been possible to reduce time-weighted average concentrations of aerosol and vapour to below 100 mg m-3. Effects on the central nervous system have only been observed at higher concentrations of the actual hydrocarbons, and male rat hydrocarbon nephropathy is not considered predictive of a normal human response. Insufficient information is available on possible long-term effects of exposure to the low-aromatic oil-based drilling fluids, especially regarding carcinogenicity and changes in the lungs.

  2. Hydrogenated Polycyclic Aromatic Hydrocarbons and the 2940 and 2850 Wavenumber (3.40 and 3.51 micron) Infrared Emission Features

    NASA Technical Reports Server (NTRS)

    Bernstein, Max P.; Sandford, Scott A.; Allamadola, Louis J.

    1996-01-01

    The 3150-2700/cm (3.17-3.70 micron) range of the spectra of a number of Ar-matrix-isolated PAHs containing excess H atoms (H(sub n)-PAHS) are presented. This region covers features produced by aromatic and aliphatic C-H stretching vibrations as well as overtone and combination bands involving lower lying fundamentals. The aliphatic C-H stretches in molecules of this type having low to modest excess H coverage provide excellent fits to a number of the weak emission features superposed on the plateau between 3080 and 2700/cm (3.25 and 3.7 micron) in the spectra of many planetary nebulae, reflection nebulae, and H II regions. Higher H coverage is implied for a few objects. We compare these results in context with the other suggested identifications of the emission features in the 2950-2700/cm (3.39-3.70 micron) region and briefly discuss their astrophysical implications.

  3. Joint Test Protocol for Validation of Alternatives to Aliphatic Isocyanate Polyurethanes

    NASA Technical Reports Server (NTRS)

    Lewis, Pattie

    2005-01-01

    The primary objective of this effort is to demonstrate and validate alternatives to aliphatic isocyanate polyurethanes. Successful completion of this project will result in one or more isocyanate-free coatings qualified for use at AFSPC and NASA installations participating in this project.

  4. Fingerprinting aliphatic hydrocarbon pollutants over agricultural lands surrounding Tehran oil refinery.

    PubMed

    Bayat, Javad; Hashemi, Seyed Hossein; Khoshbakht, Korros; Deihimfard, Reza

    2016-11-01

    The analysis of aliphatic hydrocarbons, which are composed of n-alkanes as well as branched and cyclic alkanes, can be used to distinguish between the sources of hydrocarbon contamination. In this study, the concentration of aliphatic hydrocarbons, soil pH, and organic matter in agricultural soils located south of Tehran were monitored. Eighty-three soil samples were taken from two depth ranges of 0-30 and 30-60 cm. The results showed that aliphatic compounds ranged from 0.22-68.11 mg kg(-1) at the top to 0.33-53.18 mg kg(-1) at subsoil. The amount of hydrocarbons increases from the northern parts toward the south, and hydrocarbon pollutants originated from both petroleum and non-petroleum sources. Higher concentrations of aliphatic compounds in the southern parts indicated that, aside from the practice of irrigating with untreated wastewater, leakage from oil refinery storage tanks possibly contributed to soil pollution. The results also showed that several sources have polluted the agricultural soils. It is necessary to develop a new local pollution criterion as a diagnostic index that includes not only hydrocarbons but also other parameters such as heavy metal content in both soil and untreated wastewater, surface runoff, and other irrigation water resources to determine the exact origin of pollution.

  5. A case study on the myth of emission from aliphatic amides

    NASA Astrophysics Data System (ADS)

    Singh, Avinash Kumar; Das, Sreyashi; Datta, Anindya

    2016-12-01

    For several decades, aliphatic amidic compounds have been believed to be emissive. We report that this contention is incorrect and that the anomalous emission from amides originates in fluorescent impurities generated during their synthesis. In order to make this point, we have synthesized fluorescent compounds and have compared the absorption spectra with excitation spectra.

  6. Decrease of aliphatic CHs from diatoms by in situ heating infrared microspectroscopy

    NASA Astrophysics Data System (ADS)

    Alipour, Leila; Nakashima, Satoru

    2016-04-01

    In situ heating IR microspectroscopy at 260-300°C under air and N2 conditions has been conducted on diatom frustules to examine aliphatic CH losses during heating, simulating their changes with burial-diagenesis. Assuming a reaction model made up of two first-order kinetic relations, reaction rate constants k1 and k2 and activation energies (Ea) were evaluated for aliphatic CHs. The rate constants for loss of aliphatic CHs of diatom frustules under air and N2 flow are much larger, with much smaller activation energies (57-109 kJ/mol: air; 14-44 kJ/mol: N2), than those for conventional hydrocarbon generation reactions from kerogens (170-370 kJ/mol) studied at higher temperatures (350-450°C). The CH decrease rates are somewhat different from the amide I decrease (protein degradation) rates. The obtained results suggest that organic transformation reactions including degradation of aliphatic CHs inside the diatom silica frustules might be quite different from those of kerogens separated from the biological structures.

  7. Catalytic conversion of aliphatic alcohols on carbon nanomaterials: The roles of structure and surface functional groups

    NASA Astrophysics Data System (ADS)

    Tveritinova, E. A.; Zhitnev, Yu. N.; Chernyak, S. A.; Arkhipova, E. A.; Savilov, S. V.; Lunin, V. V.

    2017-03-01

    Carbon nanomaterials with the structure of graphene and different compositions of the surface groups are used as catalysts for the conversion of C2-C4 aliphatic alcohols. The conversions of ethanol, propanol- 1, propanol-2, butanol-1, butanol-2, and tert-butanol on carbon nanotubes, nanoflakes, and nanoflakes doped with nitrogen are investigated. Oxidized and nonoxidized multiwalled carbon nanotubes, nanoflakes, and nanoflakes doped with nitrogen are synthesized. X-ray diffraction analysis, X-ray photoelectron spectroscopy, scanning and transmission electronic microscopies, Brunauer-Emmett-Teller method, derivatographic analyses, and the pulsed microcatalytic method are used to characterize comprehensively the prepared catalysts. It was established that all of the investigated carbon nanomaterials (with the exception of nondoped carbon nanoflakes) are bifunctional catalysts for the conversion of aliphatic alcohols, and promote dehydration reactions with the formation of olefins and dehydrogenation reactions with the formation of aldehydes or ketones. Nanoflakes doped with nitrogen are inert with respect to secondary alcohols and tert-butanol. The role of oxygen-containing and nitrogen-containing surface groups, and of the geometrical structure of the carbon matrix of graphene nanocarbon materials in the catalytic conversion of aliphatic alcohols, is revealed. Characteristics of the conversion of aliphatic alcohols that are associated with their structure are identified.

  8. 40 CFR 721.530 - Substituted aliphatic acid halide (generic name).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... (CONTINUED) TOXIC SUBSTANCES CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.530 Substituted aliphatic acid halide (generic name). Link to an amendment published at 79 FR 34636, June 18, 2014. (a) Chemical substance and significant new uses...

  9. PRECONCENTRATION OF ALIPHATIC AMINES FROM WATER DETERMINED BY CAPILLARY ELECTROPHORESIS WITH INDIRECT UV DETECTION

    EPA Science Inventory

    Preconcentration methodology based on adsorption chromatographies for enriching aliphatic amines (c1 to C4 substituted primary, secondary, and tertiary) and alkanolamines in water was studied by free zone capillary electrophoresis (CZE)with indirect UV detection. The solid-phase ...

  10. Modification of eucalyptus pulp fiber using silane coupling agents with aliphatic side chains of different length

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objective of this work was to evaluate the effect of three silane coupling agents with different aliphatic chain lengths on the hydrophobicity of eucalyptus pulp fiber. The three silanes coupling agents used (isobutyltrimethoxysilane, methyltrimethoxysilane, and n-octyltriethoxysilane [OTES]) we...

  11. 40 CFR 268.33 - Waste specific prohibitions-chlorinated aliphatic wastes.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 27 2011-07-01 2011-07-01 false Waste specific prohibitions-chlorinated aliphatic wastes. 268.33 Section 268.33 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID WASTES (CONTINUED) LAND DISPOSAL RESTRICTIONS Prohibitions on Land Disposal § 268.33...

  12. 40 CFR 268.33 - Waste specific prohibitions-chlorinated aliphatic wastes.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 28 2013-07-01 2013-07-01 false Waste specific prohibitions-chlorinated aliphatic wastes. 268.33 Section 268.33 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID WASTES (CONTINUED) LAND DISPOSAL RESTRICTIONS Prohibitions on Land Disposal § 268.33...

  13. 40 CFR 268.33 - Waste specific prohibitions-chlorinated aliphatic wastes.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 27 2014-07-01 2014-07-01 false Waste specific prohibitions-chlorinated aliphatic wastes. 268.33 Section 268.33 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID WASTES (CONTINUED) LAND DISPOSAL RESTRICTIONS Prohibitions on Land Disposal § 268.33...

  14. 40 CFR 268.33 - Waste specific prohibitions-chlorinated aliphatic wastes.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 28 2012-07-01 2012-07-01 false Waste specific prohibitions-chlorinated aliphatic wastes. 268.33 Section 268.33 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID WASTES (CONTINUED) LAND DISPOSAL RESTRICTIONS Prohibitions on Land Disposal § 268.33...

  15. 40 CFR 268.33 - Waste specific prohibitions-chlorinated aliphatic wastes.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 26 2010-07-01 2010-07-01 false Waste specific prohibitions-chlorinated aliphatic wastes. 268.33 Section 268.33 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID WASTES (CONTINUED) LAND DISPOSAL RESTRICTIONS Prohibitions on Land Disposal § 268.33...

  16. Air sampling and determination of vapours and aerosols of bitumen and polycyclic aromatic hydrocarbons in the Human Bitumen Study.

    PubMed

    Breuer, Dietmar; Hahn, Jens-Uwe; Höber, Dieter; Emmel, Christoph; Musanke, Uwe; Rühl, Reinhold; Spickenheuer, Anne; Raulf-Heimsoth, Monika; Bramer, Rainer; Seidel, Albrecht; Schilling, Bernd; Heinze, Evelyn; Kendzia, Benjamin; Marczynski, Boleslaw; Welge, Peter; Angerer, Jürgen; Brüning, Thomas; Pesch, Beate

    2011-06-01

    The chemical complexity of emissions from bitumen applications is a challenge in the assessment of exposure. Personal sampling of vapours and aerosols of bitumen was organized in 320 bitumen-exposed workers and 69 non-exposed construction workers during 2001-2008. Area sampling was conducted at 44 construction sites. Area and personal sampling of vapours and aerosols of bitumen showed similar concentrations between 5 and 10 mg/m(3), while area sampling yielded higher concentrations above the former occupational exposure limit (OEL) of 10 mg/m(3). The median concentration of personal bitumen exposure was 3.46 mg/m(3) (inter-quartile range 1.80-5.90 mg/m(3)). Only few workers were exposed above the former OEL. The specificity of the method measuring C-H stretch vibration is limited. This accounts for a median background level of 0.20 mg/m³ in non-exposed workers which is likely due to ubiquitous aliphatic hydrocarbons. Further, area measurements of polycyclic aromatic hydrocarbons (PAHs) were taken at 25 construction sites. U.S. EPA PAHs were determined with GC/MS, with the result of a median concentration of 2.47 μg/m(3) at 15 mastic asphalt worksites associated with vapours and aerosols of bitumen, with a Spearman correlation coefficient of 0.45 (95% CI -0.13 to 0.78). PAH exposure at mastic-asphalt works was higher than at reference worksites (median 0.21 μg/m(3)), but about one order of magnitude lower compared to coke-oven works. For a comparison of concentrations of vapours and aerosols of bitumen and PAHs in asphalt works, differences in sampling and analytical methods must to be taken into account.

  17. High aromatic ring-cleavage diversity in birch rhizosphere: PAH treatment-specific changes of I.E.3 group extradiol dioxygenases and 16S rRNA bacterial communities in soil.

    PubMed

    Sipilä, Timo P; Keskinen, Anna-Kaisa; Akerman, Marja-Leena; Fortelius, Carola; Haahtela, Kielo; Yrjälä, Kim

    2008-09-01

    Genes encoding key enzymes of catabolic pathways can be targeted by DNA fingerprinting to explore genetic degradation potential in pristine and polluted soils. We performed a greenhouse microcosm experiment to elucidate structural and functional bacterial diversity in polyaromatic hydrocarbon (PAH)-polluted soil and to test the suitability of birch (Betula pendula) for remediation. Degradation of PAHs was analysed by high-performance liquid chromatography, DNA isolated from soil amplified and fingerprinted by restriction fragment length polymorphism (RFLP) and terminal restriction fragment length polymorphism (T-RFLP). Bacterial 16S rRNA T-RFLP fingerprinting revealed a high structural bacterial diversity in soil where PAH amendment altered the general community structure as well as the rhizosphere community. Birch augmented extradiol dioxygenase diversity in rhizosphere showing a rhizosphere effect, and further pyrene was more efficiently degraded in planted pots. Degraders of aromatic compounds upon PAH amendment were shown by the changed extradiol ring-cleavage community structure in soil. The RFLP analysis grouped extradiol dioxygenase marker genes into 17 distinct operational taxonomic units displaying novel phylogenetic clusters of ring-cleavage dioxygenases representing putative catabolic pathways, and the peptide sequences contained conserved amino-acid signatures of extradiol dioxygenases. A branch of major environmental TS cluster was identified as being related to Parvibaculum lavantivorans ring-cleavage dioxygenase. The described structural and functional diversity demonstrated a complex interplay of bacteria in PAH pollution. The findings improve our understanding of rhizoremediation and unveil the extent of uncharacterized enzymes and may benefit bioremediation research by facilitating the development of molecular tools to detect and monitor populations involved in degradative processes.

  18. Two Novel Flavin-Containing Monooxygenases Involved in Biosynthesis of Aliphatic Glucosinolates

    PubMed Central

    Kong, Wenwen; Li, Jing; Yu, Qingyue; Cang, Wei; Xu, Rui; Wang, Yang; Ji, Wei

    2016-01-01

    Glucosinolates, a class of secondary metabolites from cruciferous plants, are derived from amino acids and have diverse biological activities, such as in biotic defense, depending on their side chain modification. The first structural modification step in the synthesis of aliphatic (methionine-derived) glucosinolates—S-oxygenation of methylthioalkyl glucosinolates to methylsulfinylalkyl glucosinolates—was found to be catalyzed by five flavin-containing monooxygenases (FMOs), FMOGS-OX1-5. Here, we report two additional FMOGS-OX enzymes, FMOGS-OX6, and FMOGS-OX7, encoded by At1g12130 and At1g12160, respectively. The overexpression of both FMOGS-OX6 and FMOGS-OX7 decreased the ratio of methylthioalkyl glucosinolates to the sum of methylthioalkyl and methylsulfinylalkyl glucosinolates, suggesting that the introduction of the two genes converted methylthioalkyl glucosinolates into methylsulfinylalkyl glucosinolates. Analysis of expression pattern revealed that the spatial expression of the two genes is quite similar and partially overlapped with the other FMOGS-OX genes, which are primarily expressed in vascular tissue. We further analyzed the responsive expression pattern of all the seven FMOGS-OX genes to exogenous treatment with abscisic acid, 1-aminocyclopropane-1-carboxylic acid (ACC), jasmonic acid (JA), salicylic acid, indole-3-acetic acid (IAA), and low and high temperatures. Although these genes showed same tendency toward the changing stimulus, the sensitivity of each gene was quite different. The variety in spatial expression among the FMOGS-OX genes while responding to environmental stimulus indicated a complex and finely tuned regulation of glucosinolates modifications. Identification of these two novel FMOGS-OX enzymes will enhance the understanding of glucosinolates modifications and the importance of evolution of these duplicated genes. PMID:27621741

  19. Changes in atmospheric concentrations of polycyclic aromatic hydrocarbons and polychlorinated biphenyls between the 1990s and 2010s in an Australian city and the role of bushfires as a source.

    PubMed

    Wang, Xianyu; Thai, Phong K; Li, Yan; Li, Qingbo; Wainwright, David; Hawker, Darryl W; Mueller, Jochen F

    2016-06-01

    Over recent decades, efforts have been made to reduce human exposure to atmospheric pollutants including polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) through emission control and abatement. Along with the potential changes in their concentrations resulting from these efforts, profiles of emission sources may have also changed over such extended timeframes. However relevant data are quite limited in the Southern Hemisphere. We revisited two sampling sites in an Australian city, where the concentration data in 1994/5 for atmospheric PAHs and PCBs were available. Monthly air samples from July 2013 to June 2014 at the two sites were collected and analysed for these compounds, using similar protocols to the original study. A prominent seasonal pattern was observed for PAHs with elevated concentrations in cooler months whereas PCB levels showed little seasonal variation. Compared to two decades ago, atmospheric concentrations of ∑13 PAHs (gaseous + particle-associated) in this city have decreased by approximately one order of magnitude and the apparent halving time (t1/2) was estimated as 6.2 ± 0.56 years. ∑6iPCBs concentrations (median value; gaseous + particle-associated) have decreased by 80% with an estimated t1/2 of 11 ± 2.9 years. These trends and values are similar to those reported for comparable sites in the Northern Hemisphere. To characterise emission source profiles, samples were also collected from a bushfire event and within a vehicular tunnel. Emissions from bushfires are suggested to be an important contributor to the current atmospheric concentrations of PAHs in this city. This contribution is more important in cooler months, i.e. June, July and August, and its importance may have increased over the last two decades.

  20. Biothermodynamic characterization of monocarboxylic and dicarboxylic aliphatic acids binding to human serum albumin: a flow microcalorimetric study.

    PubMed

    Aki, H; Yamamoto, M

    1993-02-01

    Thermodynamic parameters have been evaluated for the binding of unbranched monocarboyxlic aliphatic acids (MCAs) of 4 to 16 carbons (MC4 to MC16) and dicarboxylic aliphatic acids (DCAs) of 4 to 16 carbons (DC4 to DC16) to human serum albumin (HSA) on the basis of microcalorimetric measurement at pH 7.4 and 37 degrees C by computer-fitting to single- and two-class binding models. Long-chain MCAs (MC10 to MC16) and DCAs (DC14 and DC16) had the first class of binding sites with high affinity (large binding constant) of 10(5) to 10(6) M-1 and the second class with lower affinity and high capacity (large numbers of binding sites). Short- or medium-chain MCAs and DCAs bound to HSA at some low affinity binding sites. The binding constants of MCAs were ten times larger than those of DCAs. All the relationships between the thermodynamic parameters and alkyl-chain length of the acids showed clear-cut inflections in their plots around eight or nine methylene units. The free energy change of the first class of binding sites (- delta G1) became more negative with an increment of -1.0 kJ mol-1 CH2(-1) as the alkyl-chain length increased, but there were steep rises between MC9 and MC11 with -2.90 kJ mol-1 CH2(-1) and between DC9 and DC12 with -2.02 kJ mol-1 CH2(-1). The enthalpy change (- delta H) increased at the rate of -7.4 kJ mol-1 CH2(-1) to the maximum at MC9 and DC10, then decreased due to hydrophobicity of the alkyl-chains. From compensation analyses (delta H vs. delta S and delta G), HSA binding sites were characterized into three groups.

  1. Polybenzimidazoles Via Aromatic Nucleophilic Displacement

    NASA Technical Reports Server (NTRS)

    Connell, John W.; Hergenrother, Paul M.; Smith, Joseph G.

    1994-01-01

    Soluble polybenzimidazoles (PBI's) synthesized by nucleophilic displacement reaction of di(hydroxyphenyl)-benzimidazole monomers with activated aromatic difluoride compounds in presence of anhydrous potassium carbonate. These polymers exhibit good thermal, thermo-oxidative, and chemical stability, and high mechanical properties. Using benzimidazole monomers, more economical, and new PBI's processed more easily than commercial PBI, without loss of desirable physical properties.

  2. Binuclear Phthalocyanines with Aromatic Bridges

    DTIC Science & Technology

    1989-03-01

    successful. (Scheme 2) Synthesis of Binuclear Phthalocyanines Covalently Bridged by Anthracene The coupling reaction of aromatic halides using elemental...available (16), it Is not active enough to undergo the desired cross coupling reaction . Less electropositive arylzinc derivatives can tolerate various electro...philic functional groups such as nitriles and esters (17). These organo- metallic reagents readily undergo cross coupling reaction with aryl halides

  3. The Aromaticity of Pericyclic Reaction Transition States

    ERIC Educational Resources Information Center

    Rzepa, Henry S.

    2007-01-01

    An approach is presented that starts from two fundamental concepts in organic chemistry, chirality and aromaticity, and combines them into a simple rule for stating selection rules for pericyclic reactions in terms of achiral Huckel-aromatic and chiral Mobius-aromatic transition states. This is illustrated using an example that leads to apparent…

  4. The Exobiological Role of Interstellar Polycyclic Aromatic Hydrocarbons and Ices

    NASA Technical Reports Server (NTRS)

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

    2002-01-01

    Tremendous strides have been made in our understanding of interstellar material over the past twenty years thanks to significant, parallel developments in observational astronomy and laboratory astrophysics. Before this time, the composition of interstellar dust was largely guessed-at, the presence of ices in interstellar clouds ignored, and the notion that large, gas phase, carbon rich molecules might be abundant and widespread throughout the interstellar medium (ISM) considered impossible. Today, the composition of dust in the ISM is reasonably well constrained to micron-sized cold refractory materials comprised of amorphous and crystalline silicates mixed with an amorphous carbonaceous material containing aromatic structural units and short, branched aliphatic chains. Shrouded within the protective confines of cold, opaque molecular clouds--the birthplace of stars and planets--these cold dust particles secrete mantles of mixed molecular ices whose compositions are also well constrained. Finally, amidst the molecular inventory of these ice mantles are likely to be found polycyclic aromatic hydrocarbons (PAHs), shockingly large molecules by the standards of interstellar chemistry, the telltale infrared spectral signature of which is now recognized throughout the Universe. In the first part of this talk, we will review the spectroscopic evidence that forms the basis for the currently accepted abundance and ubiquity of PANs in the ISM. We will then look at a few specific examples which illustrate how experimental and theoretical data can be applied to interpret the interstellar spectra and track how the PAN population evolves as it passes from its formation site in the circumstellar outflows of dying stars, through the various phases of the ISM, and into forniing planetary systems. Nevertheless, despite the fact that PANs likely represent the single largest molecular reservoir of organic carbon in evolving planetary systems, they are not what would be considered

  5. The Infrared Spectra of Polycyclic Aromatic Hydrocarbons with Excess Peripheral H Atoms (Hn-PAHs) and their Relation to the 3.4 and 6.9 µm PAH Emission Features

    PubMed Central

    Sandford, Scott A.; Bernstein, Max P.; Materese, Christopher K.

    2015-01-01

    Polycyclic aromatic hydrocarbons (PAHs) are likely responsible for the family of infrared emission features seen in a wide variety of astrophysical environments. A potentially important subclass of these materials are PAHs whose edges contain excess H atoms (Hn-PAHs). This type of compound may be present in space, but it has been difficult to assess this possibility because of a lack of suitable laboratory spectra to assist with analysis of astronomical data. We present 4000-500 cm−1 (2.5–20 µm) infrared spectra of 23 Hn-PAHs and related molecules isolated in argon matrices under conditions suitable for interpretation of astronomical data. Spectra of molecules with mixed aromatic and aliphatic domains show characteristics that distinguish them from fully aromatic PAH equivalents. Two major changes occur as PAHs become more hydrogenated: (1) aromatic C-H stretching bands near 3.3 µm weaken and are replaced with stronger aliphatic bands near 3.4 µm, and (2) aromatic C-H out-of-plane bending mode bands in the 11–15 µm region shift and weaken concurrent with growth of a strong aliphatic -CH2-deformation mode near 6.9 µm. Implications for interpreting astronomical spectra are discussed with emphasis on the 3.4 and 6.9 µm features. Laboratory data is compared with emission spectra from IRAS 21282+5050, an object with normal PAH emission features, and IRAS 22272+5435 and IRAS 0496+3429, two protoplanetary nebulae with abnormally large 3.4 µm features. We show that ‘normal’ PAH emission objects contain relatively few Hn-PAHs in their emitter populations, but less evolved protoplanetary nebulae may contain significant abundances of these molecules. PMID:26435553

  6. The Infrared Spectra of Polycyclic Aromatic Hydrocarbons with Excess Peripheral H Atoms (Hn-PAHs) and their Relation to the 3.4 and 6.9 µm PAH Emission Features.

    PubMed

    Sandford, Scott A; Bernstein, Max P; Materese, Christopher K

    Polycyclic aromatic hydrocarbons (PAHs) are likely responsible for the family of infrared emission features seen in a wide variety of astrophysical environments. A potentially important subclass of these materials are PAHs whose edges contain excess H atoms (Hn-PAHs). This type of compound may be present in space, but it has been difficult to assess this possibility because of a lack of suitable laboratory spectra to assist with analysis of astronomical data. We present 4000-500 cm(-1) (2.5-20 µm) infrared spectra of 23 Hn-PAHs and related molecules isolated in argon matrices under conditions suitable for interpretation of astronomical data. Spectra of molecules with mixed aromatic and aliphatic domains show characteristics that distinguish them from fully aromatic PAH equivalents. Two major changes occur as PAHs become more hydrogenated: (1) aromatic C-H stretching bands near 3.3 µm weaken and are replaced with stronger aliphatic bands near 3.4 µm, and (2) aromatic C-H out-of-plane bending mode bands in the 11-15 µm region shift and weaken concurrent with growth of a strong aliphatic -CH2-deformation mode near 6.9 µm. Implications for interpreting astronomical spectra are discussed with emphasis on the 3.4 and 6.9 µm features. Laboratory data is compared with emission spectra from IRAS 21282+5050, an object with normal PAH emission features, and IRAS 22272+5435 and IRAS 0496+3429, two protoplanetary nebulae with abnormally large 3.4 µm features. We show that 'normal' PAH emission objects contain relatively few Hn-PAHs in their emitter populations, but less evolved protoplanetary nebulae may contain significant abundances of these molecules.

  7. THE INFRARED SPECTRA OF POLYCYCLIC AROMATIC HYDROCARBONS WITH EXCESS PERIPHERAL H ATOMS (H {sub n} -PAHs) AND THEIR RELATION TO THE 3.4 AND 6.9 {mu}m PAH EMISSION FEATURES

    SciTech Connect

    Sandford, Scott A.; Bernstein, Max P.; Materese, Christopher K.

    2013-03-01

    Polycyclic aromatic hydrocarbons (PAHs) are likely responsible for the family of infrared emission features seen in a wide variety of astrophysical environments. A potentially important subclass of these materials are PAHs whose edges contain excess H atoms (H {sub n} -PAHs). This type of compound may be present in space, but it has been difficult to assess this possibility because of a lack of suitable laboratory spectra to assist with analysis of astronomical data. We present 4000-500 cm{sup -1} (2.5-20 {mu}m) infrared spectra of 23 H {sub n} -PAHs and related molecules isolated in argon matrices under conditions suitable for interpretation of astronomical data. Spectra of molecules with mixed aromatic and aliphatic domains show characteristics that distinguish them from fully aromatic PAH equivalents. Two major changes occur as PAHs become more hydrogenated: (1) aromatic C-H stretching bands near 3.3 {mu}m weaken and are replaced with stronger aliphatic bands near 3.4 {mu}m, and (2) aromatic C-H out-of-plane bending mode bands in the 11-15 {mu}m region shift and weaken concurrent with growth of a strong aliphatic -CH{sub 2}- deformation mode near 6.9 {mu}m. Implications for interpreting astronomical spectra are discussed with emphasis on the 3.4 and 6.9 {mu}m features. Laboratory data is compared with emission spectra from IRAS 21282+5050, an object with normal PAH emission features, and IRAS 22272+5435 and IRAS 0496+3429, two protoplanetary nebulae with abnormally large 3.4 {mu}m features. We show that 'normal' PAH emission objects contain relatively few H {sub n} -PAHs in their emitter populations, but less evolved protoplanetary nebulae may contain significant abundances of these molecules.

  8. Determination of polycyclic aromatic hydrocarbons in diesel exhaust particulate matter and diesel fuel oil.

    PubMed

    Obuchi, A; Aoyama, H; Ohi, A; Ohuchi, H

    1984-11-16

    Clean-up procedures were developed for a method for determining the amount of polycyclic aromatic hydrocarbons (PAHs) in diesel exhaust particulate matter and in diesel fuel oils using reversed-phase high-performance liquid chromatography (HPLC). They were based mainly on the elimination of insoluble matter and aliphatic compounds that affect the performance of HPLC, from the dichloromethane extracts of particulate matter or from oils, with the aid of a disposable preparation column containing reversed-phase packings (Sep-Pak C18). Using these procedures, it is possible to detect 1 ng of benzo(a)pyrene in 30 mg of particulate matter with more than a 97% recovery or 0.5 ng in 50 microliters of oil with 91% recovery. Examples of analyses are given for particulate matter emitted from a diesel test engine and for diesel fuel oils, such as gas oil, residual oil and coal-liquefied oil.

  9. Conversion of lignin to aromatic-based chemicals (L-chems) and biofuels (L-fuels).

    PubMed

    Beauchet, R; Monteil-Rivera, F; Lavoie, J M

    2012-10-01

    Conversion of lignin into chemicals and biofuels was performed using the commercial Kraft lignin, Indulin AT. Lignin was depolymerised in an aqueous alkaline solution using a continuous flow reactor generating four fractions. First is the gas fraction (mainly CO(2)), the second includes methanol, acetic acid and formic acid, thus defined as small organic compounds and third one (up to 19.1 wt.% of lignin) is mostly composed of aromatic monomers. The fourth fraction (45-70 wt.%) contains oligomers (polyaromatic molecules) and modified lignin. Pyrocatechol was the most abundant product at high severities (315°C) with selectivity up to 25.8%. (31)P NMR showed the loss of almost all aliphatic OH groups and apparition of catechol groups during depolymerisation.

  10. Palladium-Catalyzed Hydrolytic Cleavage of Aromatic C-O Bonds.

    PubMed

    Wang, Meng; Shi, Hui; Camaioni, Donald M; Lercher, Johannes A

    2017-02-13

    Metallic palladium surfaces are highly selective in promoting the reductive hydrolysis of aromatic ethers in aqueous phase at relatively mild temperatures and pressures of H2 . At quantitative conversions, the selectivity to hydrolysis products of PhOR ethers was observed to range from 50 % (R=Ph) to greater than 90 % (R=n-C4 H9 , cyclohexyl, and PhCH2 CH2 ). By analysis of the evolution of products with and without incorporation of H2(18) O, the pathway was concluded to be initiated by palladium metal catalyzed partial hydrogenation of the phenyl group to an enol ether. Water then rapidly adds to the enol ether to form a hemiacetal, which then undergoes elimination to cyclohexanone and phenol/alkanol products. A remarkable feature of the reaction is that the stronger Ph-O bond is cleaved rather than the weaker aliphatic O-R bond.

  11. CYP63A2, a catalytically versatile fungal P450 monooxygenase capable of oxidizing higher-molecular-weight polycyclic aromatic hydrocarbons, alkylphenols, and alkanes.

    PubMed

    Syed, Khajamohiddin; Porollo, Aleksey; Lam, Ying Wai; Grimmett, Paul E; Yadav, Jagjit S

    2013-04-01

    Cytochrome P450 monooxygenases (P450s) are known to oxidize hydrocarbons, albeit with limited substrate specificity across classes of these compounds. Here we report a P450 monooxygenase (CYP63A2) from the model ligninolytic white rot fungus Phanerochaete chrysosporium that was found to possess a broad oxidizing capability toward structurally diverse hydrocarbons belonging to mutagenic/carcinogenic fused-ring higher-molecular-weight polycyclic aromatic hydrocarbons (HMW-PAHs), endocrine-disrupting long-chain alkylphenols (APs), and crude oil aliphatic hydrocarbon n-alkanes. A homology-based three-dimensional (3D) model revealed the presence of an extraordinarily large active-site cavity in CYP63A2 compared to the mammalian PAH-oxidizing (CYP3A4, CYP1A2, and CYP1B1) and bacterial aliphatic-hydrocarbon-oxidizing (CYP101D and CYP102A1) P450s. This structural feature in conjunction with ligand docking simulations suggested potential versatility of the enzyme. Experimental characterization using recombinantly expressed CYP63A2 revealed its ability to oxidize HMW-PAHs of various ring sizes, including 4 rings (pyrene and fluoranthene), 5 rings [benzo(a)pyrene], and 6 rings [benzo(ghi)perylene], with the highest enzymatic activity being toward the 5-ring PAH followed by the 4-ring and 6-ring PAHs, in that order. Recombinant CYP63A2 activity yielded monohydroxylated PAH metabolites. The enzyme was found to also act as an alkane ω-hydroxylase that oxidized n-alkanes with various chain lengths (C9 to C12 and C15 to C19), as well as alkyl side chains (C3 to C9) in alkylphenols (APs). CYP63A2 showed preferential oxidation of long-chain APs and alkanes. To our knowledge, this is the first P450 identified from any of the biological kingdoms that possesses such broad substrate specificity toward structurally diverse xenobiotics (PAHs, APs, and alkanes), making it a potent enzyme biocatalyst candidate to handle mixed pollution (e.g., crude oil spills).

  12. Alleviation of mutagenic effects of polycyclic aromatic agents (quinacrine mustard, ICR-191 and ICR-170) by caffeine and pentoxifylline.

    PubMed

    Piosik, Jacek; Ulanowska, Katarzyna; Gwizdek-Wiśniewska, Anna; Czyz, Agata; Kapuściński, Jan; Wegrzyn, Grzegorz

    2003-09-29

    Previous studies performed by others indicated that apart from its other biological effects, caffeine (CAF) may have a role in protection of organisms against cancer. However, biological mechanism of this phenomenon remained unknown. Recent studies suggested that caffeine can form stacking (pi-pi) complexes with polycyclic aromatic chemicals. Therefore, one might speculate that effective concentrations of polycyclic aromatic mutagens could be reduced in the presence of caffeine. Here we demonstrate that caffeine and another xanthine, pentoxifylline (PTX), effectively alleviate mutagenic action of polycyclic aromatic agents (exemplified by quinacrine mustard (QM), 2-methoxy-6-chloro-9-(3-(2-chloroethyl)aminopropylamino)acridine.2HCl (ICR-191) and 1,3,7-propanediamine-N-(2-chloroethyl)-N'-(6-chloro-2-methoxy-9-acridinyl)-N-ethyl.2HCl (ICR-170)), but not of aliphatic mutagens (exemplified by mechlorethamine), in the recently developed mutagenicity test based on bacterium Vibrio harveyi. Biophysical studies indicated that caffeine and pentoxifylline can form stacking complexes with the aromatic agents mentioned above. Molecular modeling also confirmed a possibility of stacking interactions between examined molecules.

  13. Registration of 'Jazzman' aromatic long-grain rice

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Jazzman is a U.S.-bred Jasmine-type, soft-cooking aromatic long-grain rice cultivar (Oryza sativa L.) that is glabrous and has no seed dormancy. It was developed from a single cross using a modified pedigree breeding method at the Rice Research Station, Louisiana State University Agriculture Center,...

  14. METHODOLOGY OF AMBIENT AIR MONITORING FOR POLYCYCLIC AROMATIC HYDROCARBONS

    EPA Science Inventory

    In the last decade, several studies of polycyclic aromatic hydrocarbons (PAH) in ambient air in the U.S. specifically investigated (1) the sampling efficiency of two sorbents for PAH in air: XAD-2 and polyurethane foam (PUP); (2) the storage stability of PAH on quartz fiber fil...

  15. Proteomic identification of protease cleavage sites characterizes prime and non-prime specificity of cysteine cathepsins B, L, and S.

    PubMed

    Biniossek, Martin L; Nägler, Dorit K; Becker-Pauly, Christoph; Schilling, Oliver

    2011-12-02

    Cysteine cathepsins mediate proteome homeostasis and have pivotal functions in diseases such as cancer. To better understand substrate recognition by cathepsins B, L, and S, we applied proteomic identification of protease cleavage sites (PICS) for simultaneous profiling of prime and non-prime specificity. PICS profiling of cathepsin B endopeptidase specificity highlights strong selectivity for glycine in P3' due to an occluding loop blocking access to the primed subsites. In P1', cathepsin B has a partial preference for phenylalanine, which is not found for cathepsins L and S. Occurrence of P1' phenylalanine often coincides with aromatic residues in P2. For cathepsin L, PICS identifies 845 cleavage sites, representing the most comprehensive PICS profile to date. Cathepsin L specificity is dominated by the canonical preference for aromatic residues in P2 with limited contribution of prime-site selectivity determinants. Profiling of cathepsins B and L with a shorter incubation time (4 h instead of 16 h) did not reveal time-dependency of individual specificity determinants. Cathepsin S specificity was profiled at pH 6.0 and 7.5. The PICS profiles at both pH values display a high degree of similarity. Cathepsin S specificity is primarily guided by aliphatic residues in P2 with limited importance of prime-site residues.

  16. 40 CFR Table 2b to Subpart E of... - Reactivity Factors for Aliphatic Hydrocarbon Solvent Mixtures

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Alkanes (2 to 460-580 Alkanes (8 to 22% Aromatics) 1.49 * Average Boiling Point = (Initial Boiling Point + Dry Point) / 2 (b) Aromatic Hydrocarbon Solvents ... Hydrocarbon Solvent Mixtures Bin Averageboiling point * (degrees F) Criteria Reactivityfactor 1 80-205...

  17. 40 CFR Table 2b to Subpart E of... - Reactivity Factors for Aliphatic Hydrocarbon Solvent Mixtures

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...-580 Alkanes (2 to 460-580 Alkanes (8 to 22% Aromatics) 1.49 * Average Boiling Point = (Initial Boiling Point + Dry Point)/2(b) Aromatic Hydrocarbon Solvents ... Hydrocarbon Solvent Mixtures Bin Averageboiling point* (degrees F) Criteria Reactivityfactor (g O3/g VOC) 1...

  18. 40 CFR Table 2b to Subpart E of... - Reactivity Factors for Aliphatic Hydrocarbon Solvent Mixtures

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...-580 Alkanes (2 to 460-580 Alkanes (8 to 22% Aromatics) 1.49 * Average Boiling Point = (Initial Boiling Point + Dry Point)/2(b) Aromatic Hydrocarbon Solvents ... Hydrocarbon Solvent Mixtures Bin Averageboiling point* (degrees F) Criteria Reactivityfactor (g O3/g VOC) 1...

  19. 40 CFR Table 2b to Subpart E of... - Reactivity Factors for Aliphatic Hydrocarbon Solvent Mixtures

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...-580 Alkanes (2 to 460-580 Alkanes (8 to 22% Aromatics) 1.49 * Average Boiling Point = (Initial Boiling Point + Dry Point)/2(b) Aromatic Hydrocarbon Solvents ... Hydrocarbon Solvent Mixtures Bin Averageboiling point* (degrees F) Criteria Reactivityfactor (g O3/g VOC) 1...

  20. 40 CFR Table 2b to Subpart E of... - Reactivity Factors for Aliphatic Hydrocarbon Solvent Mixtures

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Alkanes (2 to 460-580 Alkanes (8 to 22% Aromatics) 1.49 * Average Boiling Point = (Initial Boiling Point + Dry Point) / 2 (b) Aromatic Hydrocarbon Solvents ... Hydrocarbon Solvent Mixtures Bin Averageboiling point * (degrees F) Criteria Reactivityfactor 1 80-205...

  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. 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.

  8. alpha-Aminoalkylphosphonates as a tool in experimental optimisation of P1 side chain shape of potential inhibitors in S1 pocket of leucine- and neutral aminopeptidases.

    PubMed

    Drag, Marcin; Grembecka, Jolanta; Pawełczak, Małgorzata; Kafarski, Paweł

    2005-08-01

    The synthesis and biological activity studies of the series of structurally different alpha-aminoalkylphosphonates were performed in order to optimise the shape of the side chain of the potential inhibitors in S1 pocket of leucine aminopeptidase [E.C.3.4.11.1]. Analysis of a series of compounds with aromatic, aliphatic and alicyclic P1 side chains enabled to find out the structural features, optimal for that fragment of inhibitors of LAP. The most active among all investigated compounds were the phosphonic analogues of homo-tyrosine (K(i)=120 nM) and homo-phenylalanine (K(i)=140 nM), which even as racemic mixtures were better inhibitors in comparison with the best till now-phosphonic analogue of l-leucine (230 nM). Additional comparison of the inhibitory activity obtained for aminopeptidase N (APN, E.C.3.4.11.2) give insight into structural preferences of both enzymes.

  9. Hybrid Ionosilica containing aromatic groups

    NASA Astrophysics Data System (ADS)

    Thach, U. D.; Prelot, B.; Hesemann, P.

    2015-07-01

    Ionosilicas are defined as mesostructured silica based materials bearing covalently bound ionic groups. These materials, situated at the interface of ionic liquids and structured silica mesophases, are usually synthesized following template directed hydrolysis-polycondensation procedures starting from silylated ionic compounds. Here, we report new ammonium type hybrid ionosilicas containing aromatic groups which can serve as a new platform for the design of functional materials, for applications in the areas of ion exchange reactions, drug delivery or wastewater treatment.

  10. Tough, Soluble, Aromatic, Thermoplastic Copolyimides

    NASA Technical Reports Server (NTRS)

    Bryant, Robert G. (Inventor)

    1998-01-01

    Tough, soluble, aromatic, thermoplastic copolyimides were prepared by reacting 4,4'-oxydiphthalic anhydride, 3,4,3',4'-biphenyltetracarboxylic dianhydride and 3,4'-oxydianiline. These copolyimides were found to be soluble in common amide solvents such as N,N'-dimethyl acetamide, N-methylpyrrolidinone, and dimethylformamide allowing them to be applied as the fully imidized copolymer and to be used to prepare a wide range of articles.

  11. The direct aromatization of methane

    SciTech Connect

    Marcelin, G.; Oukaci, R.; Migone, R.A.; Kazi, A.M.

    1995-12-31

    The thermal decomposition of methane shows significant potential as a process for the production of higher unsaturated and aromatic hydrocarbons when the extent of the reaction is limited. Thermodynamic calculations have shown that when the reaction is limited to the formation of C{sub 2} to C{sub 10} products, yields of aromatics can exceed 40% at temperatures of 1200{degrees}C. Preliminary experiments have shown that when the reaction is limited to the formation of C{sub 2} to C{sub 10} products, yields of aromatics can exceed 40% at temperatures of 1200{degrees}C. Preliminary experiments have shown that cooling the product and reacting gases as the reaction proceeds can significantly reduce or eliminate the formation of solid carbon and heavier (C{sub 10+}) materials. Much work remains to be done in optimizing the quenching process and this is one of the goals of this program. Means to lower the temperature of the reaction are being studied as this result in a more feasible commercial process due to savings realized in energy and material of construction costs. The use of free-radical generators and catalysts will be investigated as a means of lowering the reaction temperature thus allowing faster quenching. It is highly likely that such studies will lead to a successful direct methane to higher hydrocarbon process.

  12. Application of polymethacrylate resin as stationary phase in liquid chromatography with UV detection for C1-C7 aliphatic monocarboxylic acids and C1-C7 aliphatic monoamines.

    PubMed

    Ohta, Kazutoku; Towata, Atsuya; Ohashi, Masayoshi; Takeuchi, Toyohide

    2004-06-11

    The application of unfunctionized polymethacrylate resin (TSKgel G3000PWXL) as a stationary phase in liquid chromatography with UV detection for C1-C7 aliphatic monocarboxylic acids (formic acid, acetic acid, propionic acid, butyric acid, isovaleric acid, valeric acid, 3,3-dimethylbutyric acid, 4-methylvaleric acid, hexanoic acid, 2-methylhexanoic acid, 5-methylhexanoic acid and heptanoic acid) and C1-C7 aliphatic monoamines (methylamine, ethylamine, propylamine, isobutylamine, butylamine, isoamylamine, amylamine, 1,3-dimethylbutylamine, hexylamine, 2-heptylamine and heptylamine) was carried out. Using dilute sulfuric acid as the eluent, the TSKgel G3000PWXL, resin acted as an advanced stationary phase for these C1-C7 carboxylic acids. Excellent simultaneous separation and symmetrical peaks for these C1-C7 carboxylic acids were achieved on a TSKgel G3000PWXL column (150 mm x 6 mm i.d.) in 60 min with 0.25 mM sulfuric acid containing 1 mM 2-methylheptanoic acid at pH 3.3 as the eluent. Using dilute sodium hydroxide as the eluent, the TSKgel G3000PWXL resin also behaved as an advanced stationary phase for these C1-C7 amines. Excellent simultaneous separation and good peaks for these C1-C7 amines were achieved on the TSKgel G3000PWXL column in 60 min with 10 mM sodium hydroxide containing 0.5 mM 1-methylheptylamine at pH 11.9 as the eluent.

  13. Spacecraft Maximum Allowable Concentrations (SMACs) for C3 to C8 Aliphatic Saturated Aldehydes

    NASA Technical Reports Server (NTRS)

    Langford, Shannon D.

    2007-01-01

    Spacecraft maximum allowable concentrations (SMACs) for C3 to C8, straight-chain, aliphatic aldehydes have been previously assessed and have been documented in volume 4 of Spacecraft Maximum Allowable Concentrations for Selected Airborne Contaminants (James, 2000). These aldehydes as well as associated physical properties are shown in Table 1. The C3 to C8 aliphatic aldehydes can enter the habitable compartments and contaminate breathing air of spacecraft by several routes including incomplete oxidation of alcohols in the Environmental Control and Life Support System (ECLSS) air revitalization subsystem, as a byproduct of human metabolism, through materials off-gassing, or during food preparation. These aldehydes have been detected in the atmosphere of manned space vehicles in the past. Analysis performed by NASA of crew cabin air samples from the Russian Mir Space Station revealed the presence of C3 to C8 aldehydes at concentrations peaking at approximately 0.1 mg/cu m.

  14. Quantification of sterols and aliphatic alcohols in Mediterranean stone pine (Pinus pinea L.) populations.

    PubMed

    Nasri, Nizar; Fady, Bruno; Triki, Saïda

    2007-03-21

    Individual components of Pinus pinea L. oil unsaponifiable matter isolated from seven Mediterranean populations were identified and quantified. P. pinea oil unsaponifiable matter contained very high levels of phytosterols (>or=4298 mg kg-1 of total extracted lipids), of which beta-sitosterol was the most abundant (74%). Aliphatic alcohol contents were 1365 mg kg-1 of total extracted lipids, of which octacosanol was the most abundant (41%). Two alcohols (hexacosanol and octacosanol), which are usually absent in common vegetable oils, were described for P. pinea oils. There were almost no differences in the total unsaponifiable matter of the seven Mediterranean populations studied. However, sterol and aliphatic alcohol contents showed some variability, with Tunisian and Moroccan populations showing very different and higher contents.

  15. Aliphatic polyester polymer stars: synthesis, properties and applications in biomedicine and nanotechnology.

    PubMed

    Cameron, Donald J A; Shaver, Michael P

    2011-03-01

    A critical review: the ring-opening polymerization of cyclic esters provides access to an array of biodegradable, bioassimilable and renewable polymeric materials. Building these aliphatic polyester polymers into larger macromolecular frameworks provides further control over polymer characteristics and opens up unique applications. Polymer stars, where multiple arms radiate from a single core molecule, have found particular utility in the areas of drug delivery and nanotechnology. A challenge in this field is in understanding the impact of altering synthetic variables on polymer properties. We review the synthesis and characterization of aliphatic polyester polymer stars, focusing on polymers originating from lactide, ε-caprolactone, glycolide, β-butyrolactone and trimethylene carbonate monomers and their copolymers including coverage of polyester miktoarm star copolymers. These macromolecular materials are further categorized by core molecules, catalysts employed, self-assembly and degradation properties and the resulting fields of application (262 references).

  16. Biodegradation of aliphatic hydrocarbons in the presence of hydroxy cucurbit[6]uril.

    PubMed

    Pasumarthi, Rajesh; Kumar, Vikash; Chandrasekharan, Sivaraman; Ganguly, Anasuya; Banerjee, Mainak; Mutnuri, Srikanth

    2014-11-15

    Aliphatic hydrocarbons are one of the major environmental pollutants with reduced bioavailability. The present study focuses on the effect of hydroxy cucurbit[6]uril on the bioavailability of hydrocarbons. A bacterial consortium was used for biodegradation studies under saline and non-saline conditions. Based on denaturing gradient gel electrophoresis results it was found that the consortium under saline conditions had two different strains. The experiment was conducted in microcosms with tetradecane, hexadecane, octadecane and mixture of the mentioned hydrocarbons as the sole carbon source. The residual hydrocarbon was quantified using gas chromatography every 24h. It was found that biodegradation of tetradecane and hexadecane, as individual carbon source increased in the presence of hydroxy CB[6], probably due to the increase in their bioavailability. In case of octadecane this did not happen. Bioavailability of all three aliphatic hydrocarbons was increased when provided as a mixture to the consortium under saline conditions.

  17. [Synthesis, characterization and fluorescent properties of copper phthalocyanine derivates substituted by aliphatic alcohol].

    PubMed

    Zhang, Liang; Xu, Qing-Feng; Lu, Jian-Mei; Yao, She-Chun

    2007-04-01

    A series of copper phthalocyanine derivatives substituted by aliphatic chain were obtained by the reaction of tetra-formyl chloride copper phthalocyanine and aliphatic alcohol such as n-butyl alcohol, n-amyl alcohol, n-hexyl alcohol, n-caprylic alcohol and lauryl alcohol. IR, UV-Vis, elemental analysis and 1H NMR verified the structures and substituting degree. The solubility and the relationship between fluorescence and concentration and substituting group were studied in organic solution. It was confirmed that the solubility in organic solution was improved greatly, the fluorescence did not change in linear according to the concentration and the fluorescence of copper phthalocyanine derivatives substituted by the long alkyl was stronger than that substituted by the relatively short alkyl.

  18. Aliphatic and alicyclic camphor imines as effective inhibitors of influenza virus H1N1.

    PubMed

    Sokolova, Anastasiya S; Yarovaya, Оlga I; Baev, Dmitry S; Shernyukov, Аndrey V; Shtro, Anna A; Zarubaev, Vladimir V; Salakhutdinov, Nariman F

    2017-02-15

    A series of camphor derived imines was synthesised and evaluated in vitro for antiviral activity. Theoretical evaluations of ADME properties were also carried out. Most of these compounds exhibited significant activity against the drug-resistant strains of influenza A virus. Especially, compounds 2 (SI = 632) and 3 (SI = 417) presented high inhibition against influenza subtypes A/Puerto Rico/8/34 and A/California/07/09 of H1N1pdm09. Analysis of the structure-activity relationship showed that the activity was strongly dependent on the length of the aliphatic chain: derivatives with a shorter chain possessed higher activity, while the suppressing action of compounds with long aliphatic chains was lower.

  19. Mild Aliphatic and Benzylic Hydrocarbon C-H Bond Chlorination Using Trichloroisocyanuric Acid.

    PubMed

    Combe, Sascha H; Hosseini, Abolfazl; Parra, Alejandro; Schreiner, Peter R

    2017-03-03

    We present the controlled monochlorination of aliphatic and benzylic hydrocarbons with only 1 equiv of substrate at 25-30 °C using N-hydroxyphthalimide (NHPI) as radical initiator and commercially available trichloroisocyanuric acid (TCCA) as the chlorine source. Catalytic amounts of CBr4 reduced the reaction times considerably due to the formation of chain-carrying ·CBr3 radicals. Benzylic C-H chlorination affords moderate to good yields for arenes carrying electron-withdrawing (50-85%) or weakly electron-donating groups (31-73%); cyclic aliphatic substrates provide low yields (24-38%). The products could be synthesized on a gram scale followed by simple purification via distillation. We report the first direct side-chain chlorination of 3-methylbenzoate affording methyl 3-(chloromethyl)benzoate, which is an important building block for the synthesis of vasodilator taprostene.

  20. Degradation of halogenated aliphatic compounds by the ammonia-oxidizing bacterium nitrosomonas europaea

    SciTech Connect

    Vannelli, T.; Logan, M.; Arciero, D.M.; Hooper, A.B. )

    1990-04-01

    Suspensions of Nitrosomonas europaea catalyzed the ammonia-stimulated aerobic transformation of the halogenated aliphatic compounds dichloromethane, dibromomethane, trichloromethane (chloroform), bromoethane, 1,2-dibromoethane (ethylene dibromide), 1,1,2-trichloroethane, 1,1,1-trichloroethane, monochloroethylene (vinyl chloride), gem-dichloroethylene, cis- and trans-dichloroethylene, cis-dibromoethylene, trichloroethylene, and 1,2,3-trichloropropane. Tetrachloromethane (carbon tetrachloride), tetrachloroethylene (perchloroethylene), and trans-dibromoethylene were not degraded.

  1. Degradation of halogenated aliphatic compounds by the ammonia-oxidizing bacterium Nitrosomonas europaea

    SciTech Connect

    Vannelli, T.; Logan, M.; Arciero, D.M.; Hooper, A.B.

    1990-01-01

    Suspensions of Nitrosomonas europaea catalyzed the ammonia-stimulated aerobic transformation of the halogenated aliphatic compounds dichloromethane, dibromomethane, trichloromethane (chloroform), bromoethane, 1,2-dibromoethane (ethylene dibromide), 1,1,2-trichloroethane, 1,1,1-trichloroethane, monochloroethylene (vinyl chloride), gem-dichloroethylene, cis- and trans-dichloroethylene, cis-dibromoethylene, trichloroethylene, and 1,2,3-trichloropropane. Tetrachloromethane (carbon tetrachloride), tetrachloroethylene (perchloroethylene), and trans-dibromoethylene were not degraded.

  2. Coefficients of caffeine distribution in aliphatic alcohol-ammonium sulfate-water systems

    NASA Astrophysics Data System (ADS)

    Korenman, Ya. I.; Krivosheeva, O. A.; Mokshina, N. Ya.

    2012-11-01

    The extraction of caffeine with aliphatic alcohols C3-C9 from aqueous solutions in the presence of a salting-out agent (ammonium sulfate) is studied. Quantitative characteristics of extraction are calculated: the distribution coefficients ( D) and the degree of recovery ( R, %). Relations are found between log D of caffeine and the length of the hydrocarbon radical in the alcohol molecule, along with certain physicochemical properties of the extragents.

  3. Gas phase heterogeneous catalytic oxidation of alkanes to aliphatic ketones and/or other oxygenates

    SciTech Connect

    Lin, Manhua; Wang, Xiang; Yeom, Younghoon

    2015-03-17

    A catalyst, its method of preparation and its use for producing aliphatic ketones by subjecting alkanes C.sub.3 to C.sub.9 to a gas phase catalytic oxidation in the presence of air or oxygen, and, optionally, steam and/or one or more diluting gases. The catalyst comprises a catalytically active mixed metal oxide phase and a suitable support material onto and/or into which the active catalytic phase id dispersed.

  4. [Comparative study of bacterial agmatinase inhibition by derivatives of putrescine and aliphatic monoamines].

    PubMed

    Khramov, V A

    1977-03-01

    Aliphatic monoamines and some putrescine derivatives (10(-3) M) are found to inhibit agmatinase from Proteus vulgaris. Constants and the type of inhibition are determined. Investigation of the temperature effect on the inhibition has revealed an exotermic character of this process. Some thermodinamic parameters of agmatinase-anylamine binding reaction are calculated. 1-Guanidobutane is obtained by means of 1-amidobutane guanidilation, and it is found to be more efficient inhibitor than monoamines.

  5. Noncomparative scaling of aromaticity through electron itinerancy

    SciTech Connect

    Paul, Satadal; Goswami, Tamal; Misra, Anirban

    2015-10-15

    Aromaticity is a multidimensional concept and not a directly observable. These facts have always stood in the way of developing an appropriate theoretical framework for scaling of aromaticity. In the present work, a quantitative account of aromaticity is developed on the basis of cyclic delocalization of π-electrons, which is the phenomenon leading to unique features of aromatic molecules. The stabilization in molecular energy, caused by delocalization of π-electrons is obtained as a second order perturbation energy for archetypal aromatic systems. The final expression parameterizes the aromatic stabilization energy in terms of atom to atom charge transfer integral, onsite repulsion energy and the population of spin orbitals at each site in the delocalized π-electrons. An appropriate computational platform is framed to compute each and individual parameter in the derived equation. The numerical values of aromatic stabilization energies obtained for various aromatic molecules are found to be in close agreement with available theoretical and experimental reports. Thus the reliable estimate of aromaticity through the proposed formalism renders it as a useful tool for the direct assessment of aromaticity, which has been a long standing problem in chemistry.

  6. DETERMINATION OF ALIPHATIC AMINES IN WATER USING DERIVATIZATION WITH FLUORESCEIN ISOTHIOCYANATE AND CAPILLARY ELECTROPHORESIS/LASER-INDUCED FLUORESCENCE DETECTION.

    EPA Science Inventory

    Detection-oriented derivatization of aliphatic amines and amine functional groups in coumpounds of environmental interest was studied using fluorescein isothiocyanate (FITC) with separation/determination by capillary electrophoresis/laser-induced fluorescence. Determinative level...

  7. A study of aliphatic amino acids using simulated vibrational circular dichroism and Raman optical activity spectra*

    NASA Astrophysics Data System (ADS)

    Ganesan, Aravindhan; Brunger, Michael J.; Wang, Feng

    2013-11-01

    Vibrational optical activity (VOA) spectra, such as vibrational circular dichroism (VCD) and Raman optical activity (ROA) spectra, of aliphatic amino acids are simulated using density functional theory (DFT) methods in both gas phase (neutral form) and solution (zwitterionic form), together with their respective infrared (IR) and Raman spectra of the amino acids. The DFT models, which are validated by excellent agreements with the available experimental Raman and ROA spectra of alanine in solution, are employed to study other aliphatic amino acids. The inferred (IR) intensive region (below 2000 cm-1) reveals the signature of alkyl side chains, whereas the Raman intensive region (above 3000 cm-1) contains the information of the functional groups in the amino acids. Furthermore, the chiral carbons of the amino acids (except for glycine) dominate the VCD and ROA spectra in the gas phase, but the methyl group vibrations produce stronger VCD and ROA signals in solution. The C-H related asymmetric vibrations dominate the VOA spectra (i.e., VCD and ROA) > 3000 cm-1 reflecting the side chain structures of the amino acids. Finally the carboxyl and the C(2)H modes of aliphatic amino acids, together with the side chain vibrations, are very active in the VCD/IR and ROA/Raman spectra, which makes such the vibrational spectroscopic methods a very attractive means to study biomolecules.

  8. Kinetics of aerobic cometabolic biodegradation of chlorinated and brominated aliphatic hydrocarbons: A review.

    PubMed

    Jesus, João; Frascari, Dario; Pozdniakova, Tatiana; Danko, Anthony S

    2016-05-15

    This review analyses kinetic studies of aerobic cometabolism (AC) of halogenated aliphatic hydrocarbons (HAHs) from 2001-2015 in order to (i) compare the different kinetic models proposed, (ii) analyse the estimated model parameters with a focus on novel HAHs and the identification of general trends, and (iii) identify further research needs. The results of this analysis show that aerobic cometabolism can degrade a wide range of HAHs, including HAHs that were not previously tested such as chlorinated propanes, highly chlorinated ethanes and brominated methanes and ethanes. The degree of chlorine mineralization was very high for the chlorinated HAHs. Bromine mineralization was not determined for studies with brominated aliphatics. The examined research period led to the identification of novel growth substrates of potentially high interest. Decreasing performance of aerobic cometabolism were found with increasing chlorination, indicating the high potential of aerobic cometabolism in the presence of medium- and low-halogenated HAHs. Further research is needed for the AC of brominated aliphatic hydrocarbons, the potential for biofilm aerobic cometabolism processes, HAH-HAH mutual inhibition and the identification of the enzymes responsible for each aerobic cometabolism process. Lastly, some indications for a possible standardization of future kinetic studies of HAH aerobic cometabolism are provided.

  9. Entropy versus aromaticity in the conformational dynamics of aromatic rings.

    PubMed

    Shishkin, Oleg V; Dopieralski, Przemyslaw; Omelchenko, Irina V; Gorb, Leonid; Latajka, Zdzislaw; Leszczynski, Jerzy

    2013-10-01

    Comparison of the results of Car-Parrinello molecular dynamics simulations of isolated benzene, pyrimidine and 1,2,4-triazine molecules reveals that the unusually low population of planar geometry of the benzene ring is caused by entropy effects despite its high aromaticity. The decrease in symmetry of the molecule results in smaller changes in entropy and Gibbs free energy due to out-of-plane deformations of the ring, leading to an increase in the population of planar geometry of the ring. This leads to differences in the topology of potential energy and Gibbs free energy surfaces.

  10. Compactness Aromaticity of Atoms in Molecules

    PubMed Central

    Putz, Mihai V.

    2010-01-01

    A new aromaticity definition is advanced as the compactness formulation through the ratio between atoms-in-molecule and orbital molecular facets of the same chemical reactivity property around the pre- and post-bonding stabilization limit, respectively. Geometrical reactivity index of polarizability was assumed as providing the benchmark aromaticity scale, since due to its observable character; with this occasion new Hydrogenic polarizability quantum formula that recovers the exact value of 4.5 a03 for Hydrogen is provided, where a0 is the Bohr radius; a polarizability based–aromaticity scale enables the introduction of five referential aromatic rules (Aroma 1 to 5 Rules). With the help of these aromatic rules, the aromaticity scales based on energetic reactivity indices of electronegativity and chemical hardness were computed and analyzed within the major semi-empirical and ab initio quantum chemical methods. Results show that chemical hardness based-aromaticity is in better agreement with polarizability based-aromaticity than the electronegativity-based aromaticity scale, while the most favorable computational environment appears to be the quantum semi-empirical for the first and quantum ab initio for the last of them, respectively. PMID:20480020

  11. Variations in the 3 Micron Spectrum across the Orion Bar: Polycyclic Aromatic Hydrocarbons and Related Molecules

    NASA Astrophysics Data System (ADS)

    Sloan, G. C.; Bregman, J. D.; Geballe, T. R.; Allamandola, L. J.; Woodward, E.

    1997-01-01

    Long-slit spectra across the Orion Bar reveal significant differences in the spatial behavior of the components of the 3 μm polycyclic aromatic hydrocarbon (PAH) spectrum. The strong PAH band at 3.29 μm generally decreases exponentially with distance from the ionization front into the molecular cloud (scale height ~12"), although excesses appear ~10" and ~20" behind the ionization front, close to layers of H2 and CO emission, respectively. The 3.40 μm PAH feature separates into two components with very different spatial distributions. The main component (at 3.395 μm), along with the 3.51 μm band and the PAH plateau (3.3-3.6 μm), shows excess emission ~10" and ~20" behind the ionization front, stronger than the excesses in the 3.29 μm band. The extra component of the 3.40 μm band, which peaks at ~3.405 μm, has a spatial distribution very similar to the H2 emission. Aromatic C--H stretches in PAHs most likely produce the 3.29 μm feature. Aliphatic C--H stretches in either attached methyl sidegroups or superhydrogenated PAHs, or perhaps both, could produce the complicated spectral and spatial structure at 3.40 μm.

  12. 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.

  13. Direct Correlation Between Aromatization of Kerogen in Organic Shales during Maturation and Its Visible Absorption Edge

    NASA Astrophysics Data System (ADS)

    Ferralis, N.; Liu, Y.; Pomerantz, A.; Grossman, J.

    2014-12-01

    The evolution of the electronic visible-range optical absorption edge of isolated kerogens type 1, 2 (from organic shales) and 3 is characterized by diffuse reflectance UV-Visible absorption spectroscopy. The functional form of the electronic absorption edge for all kerogens measured is in excellent agreement with the "Urbach tail" phenomenology. The Urbach decay width extracted from the exponential fit within the visible range is strongly correlated with the aliphatic/aromatic ratio in isolated kerogen, regardless of the kerogen type. The direct correlation is confirmed by density functional theory calculations on proxy ensemble models of kerogen. The correlation of the decay width with conventional maturity indicators such as vitrinite reflectance is found to be good within a particular kerogen type, but not consistent across different kerogen types. This is explained in terms of the evolution of the population of aromatic constituents in kerogen, which is instead directly measured through the Urbach decay. The optical absorption edge and the Urbach decay width are therefore presented as excellent candidates for the evaluation of thermal maturity in kerogen.

  14. Variations in the 3 micron spectrum across the Orion Bar: polycyclic aromatic hydrocarbons and related molecules

    NASA Technical Reports Server (NTRS)

    Sloan, G. C.; Bregman, J. D.; Geballe, T. R.; Allamandola, L. J.; Woodward, C. E.

    1997-01-01

    Long-slit spectra across the Orion Bar reveal significant differences in the spatial behavior of the components of the 3 microns polycyclic aromatic hydrocarbon (PAH) spectrum. The strong PAH band at 3.29 microns generally decreases exponentially with distance from the ionization front into the molecular cloud (scale height approximately 12"), although excesses appear approximately 10" and 20" behind the ionization front, close to layers of H2 and CO emission, respectively. The 3.40 microns PAH feature separates into two components with very different spatial distributions. The main component (at 3.395 microns), along with the 3.51 microns band and the PAH plateau (3.3-3.6 microns), shows excess emission approximately 10" and approximately 20" behind the ionization front, stronger than the excesses in the 3.29 microns band. The extra component of the 3.40 microns band, which peaks at approximately 3.405 microns, has a spatial distribution very similar to the H2 emission. Aromatic C-H stretches in PAHs most likely produce the 3.29 microns feature. Aliphatic C-H stretches in either attached methyl side-groups or superhydrogenated PAHs, or perhaps both, could produce the complicated spectral and spatial structure at 3.40 microns.

  15. Solid state 19F NMR parameters of fluorine-labeled amino acids. Part I: Aromatic substituents

    NASA Astrophysics Data System (ADS)

    Dürr, Ulrich H. N.; Grage, Stephan L.; Witter, Raiker; Ulrich, Anne S.

    2008-03-01

    Structural parameters of peptides and proteins in biomembranes can be directly measured by solid state NMR of selectively labeled amino acids. The 19F nucleus is a promising label to overcome the low sensitivity of 2H, 13C or 15N, and to serve as a background-free reporter group in biological compounds. To make the advantages of solid state 19F NMR fully available for structural studies of polypeptides, we have systematically measured the chemical shift anisotropies and relaxation properties of the most relevant aromatic and aliphatic 19F-labeled amino acids. In this first part of two consecutive contributions, six different 19F-substituents on representative aromatic side chains were characterized as polycrystalline powders by static and MAS experiments. The data are also compared with results on the same amino acids incorporated in synthetic peptides. The spectra show a wide variety of lineshapes, from which the principal values of the CSA tensors were extracted. In addition, temperature-dependent T1 and T2 relaxation times were determined by 19F NMR in the solid state, and isotropic chemical shifts and scalar couplings were obtained in solution.

  16. Polyethylene-water partitioning coefficients for parent- and alkylated-polycyclic aromatic hydrocarbons and polychlorinated biphenyls.

    PubMed

    Choi, Yongju; Cho, Yeo-Myoung; Luthy, Richard G

    2013-07-02

    We report polyethylene (PE)-water partitioning coefficients (K(PE)) for 17 parent-polycyclic aromatic hydrocarbons (PAHs), 22 alkylated-PAHs, 3 perdeuterated parent-PAHs, and 100 polychlorinated biphenyl (PCB) congeners or coeluting congener groups. The K(PE) values for compounds in the same homologue group are within 0.2 log units for alkylated-PAHs but span up to an order of magnitude for PCBs, due to the greater contribution of the position of the substituents (i.e., chlorines for PCBs and alkyl groups for alkylated-PAHs) to the molecular structure. The K(PE) values in deionized water for parent- and alkylated-PAHs show a good correlation with a regression model employing the number of aromatic carbons (C(AR)) and aliphatic carbons (C(AL)) in each compound: log K(PE) = -0.241 + 0.313 C(AR) + 0.461 C(AL). The regression model is useful for the assessment of freely dissolved aqueous concentrations of alkylated-PAHs, which comprise a significant fraction of the total in petroleum-derived PAHs and in some pyrogenic PAH mixtures. For PCBs, experimentally determined octanol-water partitioning coefficients are the best predictor of the K(PE) values among the molecular parameters studied. The effect of salinity up to 20 or 30 parts per thousand is found to be relatively insignificant on K(PE) values for PAHs or PCBs, respectively.

  17. The Design of Reactions, Catalysts and Materials with Aromatic Ions

    NASA Astrophysics Data System (ADS)

    Bandar, Jeffrey Scott

    This thesis details the use of aromatic ions, especially aminocyclopropenium ions, as empowering design elements in the development of new chemical reactions, organic catalysts and polymeric materials. A particular focus is placed throughout on understanding the relationship between the structure of aromatic ions and their performance in these novel applications. Additionally, the benefits that aromatic ions provide in these contexts are highlighted. The first chapter briefly summarizes the Lambert Group's prior efforts toward exploiting the unique reactivity profiles of aromatic ions in the context of new reaction design. Also provided in the first chapter is a comprehensive literature review of aminocyclopropenium ions, upon which the majority of advances described in this thesis are based. To set the stage for the first application of aminocyclopropenium ions, Chapter 2 provides an account of existing highly Bronsted basic functional groups, including guanidines, proazaphosphatranes and iminophosphoranes. The provided review on the synthesis and use in asymmetric catalysis of these bases indicates that there is a high need for conceptually new Bronsted basic functional groups. To address this need, the development of chiral 2,3-bis(dialkylamino)cyclopropenimines as a new platform for asymmetric Bronsted base catalysis is described in Chapter 3. This new class of Bronsted base is readily synthesized on scale, operates efficiently under practical conditions, and greatly outperforms closely related guanidine-based catalysts. Structure-activity relationship studies, mechanistic experiments and computational transition state modeling are all discussed in the context of asymmetric glycinate imine Michael reactions in order to arrive at a working model for cyclopropenimine chemistry. Cumulatively, this chapter provides a "user's guide" to understanding and developing further applications of 2,3-bis(dialkylamino)cyclopropenimines. The use of our optimal chiral 2,3-bis

  18. Degradation of polynuclear aromatic hydrocarbons by two strains of Pseudomonas.

    PubMed

    Nwinyi, Obinna C; Ajayi, Oluseyi O; Amund, Olukayode O

    2016-01-01

    The goal of this investigation was to isolate competent polynuclear aromatic hydrocarbons degraders that can utilize polynuclear aromatic hydrocarbons of former industrial sites at McDoel Switchyard in Bloomington, Indiana. Using conventional enrichment method based on soil slurry, we isolated, screened and purified two bacterial species strains PB1 and PB2. Applying the ribotyping technique using the 16S rRNA gene analysis, the strains were assigned to the genus Pseudomonas (Pseudomonas plecoglossicida strain PB1 and Pseudomonas sp. PB2). Both isolates showed promising metabolic capacity on pyrene sprayed MS agar plates during the preliminary investigations. Using time course studies in the liquid cultures at calculated concentrations 123, 64, 97 and 94ppm for naphthalene, chrysene, fluroanthene and pyrene, P. plecoglossicida strain PB1 and Pseudomonas sp. PB2 showed partial utilization of the polynuclear aromatic hydrocarbons. Naphthalene was degraded between 26% and 40%, chrysene 14% and 16%, fluroanthene 5% and 7%; pyrene 8% and 13% by P. plecoglossicida strain PB1 and Pseudomonas sp. PB2 respectively. Based on their growth profile, we developed a model R(2)=1 to predict the degradation rate of slow polynuclear aromatic hydrocarbon-degraders where all the necessary parameters are constant. From this investigation, we confirm that the former industrial site soil microbial communities may be explored for the biorestoration of the industrial site.

  19. Rate and pathways for the reaction of OH with the biogenic p-cymene, an alkylated aromatic

    NASA Astrophysics Data System (ADS)

    Strekowski, R.; Rayez, M.-T.; Rayez, J.-C.; Zetzsch, C.

    2009-04-01

    Aromatics are known to contribute strongly to tropospheric formation of ozone, and p-cymene (4-isopropyltoluene) is one of only a few biogenic, volatile aromatic hydrocarbons. In spite of its symmetry, this molecule (CH3 - °-CH(CH3)2) has a multitude of potential pathways of its reaction with OH radicals. Addition of OH is well-known to be the predominating primary step in the tropospheric transformation of aromatic hydrocarbons. The addition is expected to occur preferably at a non-occupied position, where four positions are available: two equivalent ones ortho to the methyl group and two equivalent ones ortho to the isopropyl group. Furthermore, various C-H bonds (4 aromatic and 10 aliphatic) are available for abstraction, leading to benzyl-type radicals in two cases. The present study combines theoretical calculations with kinetic experiments in the gas phase. The theoretical calculations are based on electronic quantum chemistry DFT method for the investigation of the possible pathways in the potential energy surface of the reaction. The experiments are carried out by the flash photolysis/resonance fluorescence technique. OH radicals are produced by pulsed vacuum-UV photolysis of H2O (> 115 nm) in the presence of p-cymene in a slow flow of He as carrier gas. Their pseudo-first-order decays are monitored by resonance fluorescence, storing the photon counts by multichannel scaling in a PC and accumulating 50 decays each; see Koch et al. (2007) for details of the technique and evaluation of data. The temperature was varied between room temperature (295 K) and 345K, the He pressure was 250 mbar, and the level of p-cymene was increased stepwise, up to 3 x 1013 molecules/cm3. The decays of OH were observed to be exponential at room temperature, becoming clearly biexponential at higher temperatures, thus indicating reversible addition of OH according to the equilibration OH + p-cymene ⇔ p-cymene-OH (1, -1) These reactions might be accompanied by various

  20. Birds and polycyclic aromatic hydrocarbons

    USGS Publications Warehouse

    Albers, P.H.

    2006-01-01

    Polycyclic aromatic hydrocarbons (PAH) are present throughout the global environment and are produced naturally and by activities of humans. Effects of PAH on birds have been determined by studies employing egg injection, egg immersion, egg shell application, single and multiple oral doses, subcutaneous injection, and chemical analysis of field-collected eggs and tissue. The four-to six-ring aromatic compounds are the most toxic to embryos, young birds, and adult birds. For embryos, effects include death, developmental abnormalities, and a variety of cellular and biochemical responses. For adult and young birds, effects include reduced egg production and hatching, increased clutch or brood abandonment, reduced growth, increased organweights, and a variety of biochemical responses. Trophic level accumulation is unlikely. Environmental exposure to PAH in areas of high human population or habitats affected by recent petroleum spills might be sufficient to adversely affect reproduction. Evidence of long-term effects of elevated concentrations of environmental PAH on bird populations is very limited and the mechanisms of effect are unclear.

  1. Plasma polymerization and deposition of linear, cyclic and aromatic fluorocarbons on (100)-oriented single crystal silicon substrates

    NASA Astrophysics Data System (ADS)

    Yang, G. H.; Oh, S. W.; Kang, E. T.; Neoh, K. G.

    2002-11-01

    Fluoropolymer films were deposited on the Ar plasma-pretreated Si(100) surfaces by plasma polymerization of perfluorohexane (PFH, a linear fluorocarbon), perfluoro(methylcyclohexane) (MCH, a cyclic fluorocarbon), and hexafluorobenzene (HFB, an aromatic fluorocarbon) under different glow discharge conditions. The effects of the radio-frequency plasma power on the chemical composition and structure of the plasma-polymerized fluoropolymer films were studied by x-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, time-of-flight secondary ion mass spectrometry, and water contact angle measurements. The changes in structure and composition of the three types of the plasma-deposited films from those of the respective fluorocarbons were compared. Under similar glow discharge conditions: (i) the extent of defluorination was highest for the PFH polymer, (ii) the deposition rate was highest for the HFB polymer, (iii) the cyclic structure of MCH was less well preserved than the aromatic structure of HFB, (iv) aliphatic structures appeared in the plasma-deposited MCH polymer, and (v) the plasma-polymerized HFB has the highest thermal stability due to the preservation of the aromatic rings. The adhesive tape peel test results revealed that the plasma-polymerized and deposited fluoropolymer layers were strongly bonded to the Ar plasma-pretreated Si(100) surfaces.

  2. 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.

  3. Simultaneous Determination of 13 Priority Polycyclic Aromatic Hydrocarbons in Tehran’s Tap Water and Water for Injection Samples Using Dispersive Liquid-Liquid Micro Extraction Method and Gas Chromatography-Mass Spectrometry

    PubMed Central

    Sadeghi, Ramezan; Kobarfard, Farzad; Yazdanpanah, Hassan; Eslamizad, Samira; Bayate, Mitra

    2016-01-01

    Polycyclic aromatic hydrocarbons (PAHs) are classified as persistent and carcinogenic organic pollutants. PAHs contamination has been reported in water. Many of relevant regulatory bodies such as EU and EPA have regulated the limit levels for PAHs in drinking water. In this study, 13 priority polycyclic aromatic hydrocarbons (PAHs) were determined in tap water samples of Tehran and water for injection. Dispersive liquid-liquid microextraction procedure combined with gas chromatography-mass spectrometry was used for the extraction and determination of PAHs in the samples. Under the optimized conditions, the range of extraction recoveries and relative standard deviations (RSDs) of PAHs in water using internal standard (anthracene-d10) were in the range of 71-90% and 4-16%, respectively. Limit of detection for different PAHs were between 0.03 and 0.1 ngmL-1. The concentration of PAHs in all tap water as well as water for injection samples were lower than the limit of quantification of PAHs. This is the first study addressing the occurrence of PAHs in water for injection samples in Iran using dispersive liquid-liquid micro extraction procedure combined with gas chromatography-mass spectrometry. PMID:27642318

  4. Aromatic Polyimides With Group VI Linkages

    NASA Technical Reports Server (NTRS)

    St. Clair, T. L.; Burks, H. D.; Ely, R. M.

    1983-01-01

    New polymer system combines thermal and solvent resistant properties of aromatic polyimides with processability of PPX polymers. PPX polymers include polyphenylene oxide, polyphenylene sulfide, and polyphenylene sulfone classes. Generally more processable by hot melt or thermoplastic techniques than aromatic polyimides. PPX systems more susceptible to attack by solvents and have lower glass transition temperatures than PI group.

  5. 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.

  6. Estimating the octanol/water partition coefficient for aliphatic organic compounds using semi-empirical electrotopological index.

    PubMed

    Souza, Erica Silva; Zaramello, Laize; Kuhnen, Carlos Alberto; Junkes, Berenice da Silva; Yunes, Rosendo Augusto; Heinzen, Vilma Edite Fonseca

    2011-01-01

    A new possibility for estimating the octanol/water coefficient (log P) was investigated using only one descriptor, the semi-empirical electrotopological index (I(SET)). The predictability of four octanol/water partition coefficient (log P) calculation models was compared using a set of 131 aliphatic organic compounds from five different classes. Log P values were calculated employing atomic-contribution methods, as in the Ghose/Crippen approach and its later refinement, AlogP; using fragmental methods through the ClogP method; and employing an approach considering the whole molecule using topological indices with the MlogP method. The efficiency and the applicability of the I(SET) in terms of calculating log P were demonstrated through good statistical quality (r > 0.99; s < 0.18), high internal stability and good predictive ability for an external group of compounds in the same order as the widely used models based on the fragmental method, ClogP, and the atomic contribution method, AlogP, which are among the most used methods of predicting log P.

  7. Oxyfunctionalization of aliphatic compounds by a recombinant peroxygenase from Coprinopsis cinerea.

    PubMed

    Babot, Esteban D; del Río, José C; Kalum, Lisbeth; Martínez, Angel T; Gutiérrez, Ana

    2013-09-01

    The goal of this study is the selective oxyfunctionalization of aliphatic compounds under mild and environmentally friendly conditions using a low-cost enzymatic biocatalyst. This could be possible taking advantage from a new peroxidase type that catalyzes monooxygenase reactions with H2 O2 as the only cosubstrate (peroxygenase). With this purpose, recombinant peroxygenase, from gene mining in the sequenced genome of Coprinopsis cinerea and heterologous expression using an industrial fungal host, is tested for the first time on aliphatic substrates. The reaction on free and esterified fatty acids and alcohols, and long-chain alkanes was followed by gas chromatography, and the different reaction products were identified by mass spectrometry. Regioselective hydroxylation of saturated/unsaturated fatty acids was observed at the ω-1 and ω-2 positions (only at the ω-2 position in myristoleic acid). Alkyl esters of fatty acids and monoglycerides were also ω-1 or ω-2 hydroxylated, but di- and tri-glycerides were not modified. Fatty alcohols yielded hydroxy derivatives at the ω-1 or ω-2 positions (diols) but also fatty acids and their hydroxy derivatives. Interestingly, the peroxygenase was able to oxyfunctionalize alkanes giving, in addition to alcohols at positions 2 or 3, dihydroxylated derivatives at both sides of the molecule. The predominance of mono- or di-hydroxylated derivatives seems related to the higher or lower proportion of acetone, respectively, in the reaction medium. The recombinant C. cinerea peroxygenase appears as a promising biocatalyst for alkane activation and production of aliphatic oxygenated derivatives, with better properties than the previously reported peroxygenase from Agrocybe aegerita, and advantages related to its recombinant nature for enzyme engineering and industrial production.

  8. The galactic distribution of aliphatic hydrocarbons in the diffuse interstellar medium

    NASA Technical Reports Server (NTRS)

    Sandford, Scott A.; Pendleton, Yvonne J.; Allamandola, Louis J.

    1995-01-01

    The infrared absorption feature near 2950(exp -1) (3.4 micron), characteristic of dust in the diffuse interstellar medium (ISM), is attributed to C-H stretching vibrations of aliphatic hydrocarbons. We show here that the strength of the band does not scale linearly with visual extinction everywhere, but instead increases more rapidly for objects near the center of the Galaxy, a behavior that parallels that of the Si-O stretching band due to silicate materials in the diffuse ISM. This implies that the grains responsible for the diffuse medium aliphatic C-H and silicate Si-O stretching bands are different from those responsible for much of the observed visual extinction. It also suggests that the distribution of the carbonaceous component of the diffuse ISM is not uniform throughout the Galaxy, but instead may increase in density toward the center of the Galaxy. The similar behavior of the C-H and Si-O stretching bands suggests that these two components may be coupled, perhaps in the form of silicate-core, organic-mantle grains. Several possible models of the distribution of this material are presented and it is demonstrated that the inner parts of the Galaxy has a carrier density that is 5 to 35 times higher than in the local ISM. Depending on the model used, the density of aliphatic material in the local ISM is found to be about 1 to 2 -CH3 groups m(exp -3) and about 2 to 5 -CH2- groups m(exp -3). These densities are consistent with the strengths of the 2955 and 2925 cm(exp -1) (3.4 micron) band being described by the relations A(sub nu)/tau(sub 2955 cm(exp -1)) = 270 +/- 40 and A(sub nu)/tau(sub 2925 cm(exp -1)) = 250 +/- 40 in the local diffuse ISM.

  9. Increased mean aliphatic lipid chain length in left ventricular hypertrophy secondary to arterial hypertension

    PubMed Central

    Evaristi, Maria Francesca; Caubère, Céline; Harmancey, Romain; Desmoulin, Franck; Peacock, William Frank; Berry, Matthieu; Turkieh, Annie; Barutaut, Manon; Galinier, Michel; Dambrin, Camille; Polidori, Carlo; Miceli, Cristina; Chamontin, Bernard; Koukoui, François; Roncalli, Jerôme; Massabuau, Pierre; Smih, Fatima; Rouet, Philippe

    2016-01-01

    Abstract About 77.9 million (1 in 4) American adults have high blood pressure. High blood pressure is the primary cause of left ventricular hypertrophy (LVH), which represents a strong predictor of future heart failure and cardiovascular mortality. Previous studies have shown an altered metabolic profile in hypertensive patients with LVH. The goal of this study was to identify blood metabolomic LVH biomarkers by 1H NMR to provide novel diagnostic tools for rapid LVH detection in populations of hypertensive individuals. This cross-sectional study included 48 hypertensive patients with LVH matched with 48 hypertensive patients with normal LV size, and 24 healthy controls. Two-dimensional targeted M-mode echocardiography was performed to measure left ventricular mass index. Partial least squares discriminant analysis was used for the multivariate analysis of the 1H NMR spectral data. From the 1H NMR-based metabolomic profiling, signals coming from methylene (–CH2–) and methyl (–CH3) moieties of aliphatic chains from plasma lipids were identified as discriminant variables. The –CH2–/–CH3 ratio, an indicator of the mean length of the aliphatic lipid chains, was significantly higher (P < 0.001) in the LVH group than in the hypertensive group without LVH and controls. Receiver operating characteristic curve showed that a cutoff of 2.34 provided a 52.08% sensitivity and 85.42% specificity for discriminating LVH (AUC = 0.703, P-value < 0.001). We propose the –CH2–/–CH3 ratio from plasma aliphatic lipid chains as a biomarker for the diagnosis of left ventricular remodeling in hypertension. PMID:27861330

  10. Potential Alternatives Report for Validation of Alternatives to Aliphatic Isocyanate Polyurethanes

    NASA Technical Reports Server (NTRS)

    Lewis, pattie

    2011-01-01

    Identifying and selecting alternative materials and technologies that have the potential to reduce the identified HazMats and hazardous air pollutants (HAPs), while incorporating sound corrosion prevention and control technologies, is a complicated task due to the fast pace at which new technologies emerge and rules change. The alternatives are identified through literature searches, electronic database and Internet searches, surveys, and/or personal and professional contacts. Available test data was then compiled on the proposed alternatives to determine if the materials meet the test objectives or if further)laboratory or field-testing will be required. After reviewing technical information documented in the PAR, government representatives, technical representatives from the affected facilities, and other stakeholders involved in the process will select the list of viable alternative coatings for consideration and testing under the project's Joint Test Protocol entitled Joint Test Protocol for Validation of Alternatives to Aliphatic Isocyanate Polyurethanes and Field Test Plan entitled Field Evaluations Test Plan for Validation of Alternatives to Aliphatic Isocyanate Polyurethanes, both prepared by ITB. Test results will be reported in a Joint Test Report upon completion oftesting. The selection rationale and conclusions are documented in this PAR. A cost benefit analysis will be prepared to quantify the estimated capital and process costs of coating alternatives and cost savings relative to the current coating processes, however, some initial cost data has been included in this PAR. For this coatings project, isocyanates, as found in aliphatic isocyanate polyurethanes, were identified as the target HazMat to be eliminated. Table 1-1 lists the target HazMats, the related process and application, current specifications, and affected programs.

  11. 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.

  12. Metal-free oxidation of aromatic carbon-hydrogen bonds through a reverse-rebound mechanism.

    PubMed

    Yuan, Changxia; Liang, Yong; Hernandez, Taylor; Berriochoa, Adrian; Houk, Kendall N; Siegel, Dionicio

    2013-07-11

    Methods for carbon-hydrogen (C-H) bond oxidation have a fundamental role in synthetic organic chemistry, providing functionality that is required in the final target molecule or facilitating subsequent chemical transformations. Several approaches to oxidizing aliphatic C-H bonds have been described, drastically simplifying the synthesis of complex molecules. However, the selective oxidation of aromatic C-H bonds under mild conditions, especially in the context of substituted arenes with diverse functional groups, remains a challenge. The direct hydroxylation of arenes was initially achieved through the use of strong Brønsted or Lewis acids to mediate electrophilic aromatic substitution reactions with super-stoichiometric equivalents of oxidants, significantly limiting the scope of the reaction. Because the products of these reactions are more reactive than the starting materials, over-oxidation is frequently a competitive process. Transition-metal-catalysed C-H oxidation of arenes with or without directing groups has been developed, improving on the acid-mediated process; however, precious metals are required. Here we demonstrate that phthaloyl peroxide functions as a selective oxidant for the transformation of arenes to phenols under mild conditions. Although the reaction proceeds through a radical mechanism, aromatic C-H bonds are selectively oxidized in preference to activated Csp3-H bonds. Notably, a wide array of functional groups are compatible with this reaction, and this method is therefore well suited for late-stage transformations of advanced synthetic intermediates. Quantum mechanical calculations indicate that this transformation proceeds through a novel addition-abstraction mechanism, a kind of 'reverse-rebound' mechanism as distinct from the common oxygen-rebound mechanism observed for metal-oxo oxidants. These calculations also identify the origins of the experimentally observed aryl selectivity.

  13. Iron-Catalyzed Oxyfunctionalization of Aliphatic Amines at Remote Benzylic C-H Sites.

    PubMed

    Mbofana, Curren T; Chong, Eugene; Lawniczak, James; Sanford, Melanie S

    2016-09-02

    We report the development of an iron-catalyzed method for the selective oxyfunctionalization of benzylic C(sp(3))-H bonds in aliphatic amine substrates. This transformation is selective for benzylic C-H bonds that are remote (i.e., at least three carbons) from the amine functional group. High site selectivity is achieved by in situ protonation of the amine with trifluoroacetic acid, which deactivates more traditionally reactive C-H sites that are α to nitrogen. The scope and synthetic utility of this method are demonstrated via the synthesis and derivatization of a variety of amine-containing, biologically active molecules.

  14. Electrooxidation of aliphatic alcohols on electrodes consisting of hydrophobicized supports coated with nickel oxides

    SciTech Connect

    Chaenko, N.V.; Kornienko, V.L.; Avrutskaya, I.A.; Fioshin, M.Ya.

    1987-12-01

    Two methods are presented to intensify the electrooxidation of aliphatic alcohols with low water solubility and to simplify end-product separation. One method comprised direct addition of higher nickel oxides to the active material of the electrode to be fabricated; the other involved depositing a layer of higher nickel oxides on a hydrophobicized support consisting of a mixture of a conducting material and the FP-4D hydrophobicizer. Electrolysis was carried out in a diaphragm-free two-compartment cell, one reagent and the other the electrolyte. Results are shown of hexyl alcohol oxidation on various composition supports coated with higher nickel oxides.

  15. Pharmacological activities of cilantro’s aliphatic Aldehydes against leishmania donovani

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Leishmaniasis is a chronic infectious disease caused by different Leishmania species. Global occurrences of this disease are primarily limited to tropical and subtropical regions. Treatments are available; however, patients complain of side effects. Different species of plants have been screened as ...

  16. 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.

  17. Understanding crystallinity in aromatic polyimides

    NASA Technical Reports Server (NTRS)

    Celarier, Edward A.

    1992-01-01

    Aromatic polyimides are a class of polymers that show remarkable thermal stability, strength, and toughness. These properties make them attractive candidates for use in high-performance carbon fiber composites for airborne and spaceborne structural components. Our research centered on the development of an understanding of the underlying process of crystallite formation in a particular class of aryl polyimides for which there are some x-ray crystallographic data available. The ultimate aim of the project is to be able to develop a model sufficiently flexible to be able, on the basis of the chemical structure of a polymer in this class, to predict: (1) whether it will be prone to form crystallites; (2) crystallographic features of the crystallites; and (3) synthesis and/or processing conditions that will be favorable or unfavorable to crystallite formation. This will provide guidance to the laboratory chemists in their choice of candidate polymers and processing methods.

  18. Polycyclic aromatic hydrocarbons in carcinogenesis.

    PubMed Central

    Warshawsky, D

    1999-01-01

    A symposium on "Polycyclic Aromatic Hydrocarbons (PAHs) in Carcinogenesis" was presented at the third International Congress of Pathophysiology held in Lathi, Finland, 28 June-3 July 1998. The congress was also sponsored by the International Union of Biological Sciences and the International Society of Free Radical Research. Institutional support for the symposium included the Electric Power Research Institute, National Center for Toxicological Research, and EPA/National Health and Environmental Effects Research Laboratory and the Office of Solid Waste and Emergency Response. The symposium focused on the sources, carcinogenicity, genotoxicity, and risk assessment of individual and mixtures of PAHs that are found in solid wastes, Superfund sites, and other hazardous waste sites. Based on the occurrence of PAHs at numerous Superfund sites and the significant data gaps on the toxic potential of certain PAHs, the information developed during this symposium would be of value in assessing health risks of these chemicals at Superfund and other hazardous waste sites. PMID:10090712

  19. 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.

  20. 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.

  1. PRACTICAL SYNTHESIS OF AROMATIC DITHIOCARBAMATES

    PubMed Central

    Padungros, Panuwat; Wei, Alexander

    2015-01-01

    GRAPHICAL ABSTRACT Oxidation-sensitive N,N-diaryl dithiocarbamates (DTCs) are synthesized in good yields by the generation of metal amide salts from N-benzoyl precursors, followed by addition of CS2. para-Substituted diphenylamines are prepared by electrophilic aromatic substitution of diphenylbenzamide and saponification. Deacylation of electron-rich species such as bis(p-dimethylaminophenyl)benzamide is challenging because of the oxidative sensitivity of the anionic intermediate but could be achieved in good yield by using n-BuLi to generate a hemiaminal adduct, prior to acidification. The N,N-diaryl DTCs are stable as alkali salts and can be used to produce densely packed monolayers on gold surfaces. PMID:25999616

  2. Synthesis of perfluoroalkylene aromatic diamines

    NASA Technical Reports Server (NTRS)

    Paciorek, K. L.; Ito, T. I.; Nakahara, J. H.; Kratzer, R. H.

    1978-01-01

    Analogues of methylene dianilines were synthesized, in which the methylene group between the two aromatic nuclei was replaced by various perfluoroalkylene linkage. The hydrolytic thermal, and thermal oxidative stabilities of PMR Polyimides derived from these diamines were determined. Three types of PMR Polyimide discs were fabricated from the dimethyl ester of 3,3', 4,4'-benzophenonetetracarboxylic acid, the methyl ester of 5-norbornene-2,3-dicarboxylic acid, and one of the following three diamines: methyl dianiline, 1,3-bis(4-aminophenyl)hexafluoropropane, and 2,2-bis(4-aminophenyl)hexafluoropropane. The polyimide based on 2,2-bis(4-aminophenyl)hexafluoropropane exhibited the best hydrolytic, thermal, and thermal oxidative stability as determined by moisture uptake and thermogravimetric analysis.

  3. Tough soluble aromatic thermoplastic copolyimides

    NASA Technical Reports Server (NTRS)

    Bryant, Robert G. (Inventor)

    2000-01-01

    Tough, soluble, aromatic, thermoplastic copolyimides were prepared by reacting 4,4'-oxydiphthalic anhydride, 3,4,3',4'-biphenyltetracarboxylic dianhydride and 3,4'-oxydianiline. Alternatively, these copolyimides may be prepared by reacting 4,4'-oxydiphthalic anhydride with 3,4,3',4'-biphenyltetracarboxylic dianhydride and 3,4'-oxydiisocyanate. Also, the copolyimide may be prepared by reacting the corresponding tetra acid and ester precursors of 4,4'-oxydiphthalic anhydride and 3,4,3',4'-biphenyltetracarboxylic dianhydride with 3,4'-oxydianiline. These copolyimides were found to be soluble in common amide solvents such as N,N'-dimethyl acetamide, N-methylpyrrolidinone, and dimethylformamide allowing them to be applied as the fully imidized copolymer and to be used to prepare a wide range of articles.

  4. Synthesis and conformational analysis of hybrid α/β-dipeptides incorporating S-glycosyl-β(2,2)-amino acids.

    PubMed

    García-González, Iván; Mata, Lara; Corzana, Francisco; Jiménez-Osés, Gonzalo; Avenoza, Alberto; Busto, Jesús H; Peregrina, Jesús M

    2015-01-12

    We synthesized and carried out the conformational analysis of several hybrid dipeptides consisting of an α-amino acid attached to a quaternary glyco-β-amino acid. In particular, we combined a S-glycosylated β(2,2)-amino acid and two different types of α-amino acid, namely, aliphatic (alanine) and aromatic (phenylalanine and tryptophan) in the sequence of hybrid α/β-dipeptides. The key step in the synthesis involved the ring-opening reaction of a chiral cyclic sulfamidate, inserted in the peptidic sequence, with a sulfur-containing nucleophile by using 1-thio-β-D-glucopyranose derivatives. This reaction of glycosylation occurred with inversion of configuration at the quaternary center. The conformational behavior in aqueous solution of the peptide backbone and the glycosidic linkage for all synthesized hybrid glycopeptides was analyzed by using a protocol that combined NMR experiments and molecular dynamics with time-averaged restraints (MD-tar). Interestingly, the presence of the sulfur heteroatom at the quaternary center of the β-amino acid induced θ torsional angles close to 180° (anti). Notably, this value changed to 60° (gauche) when the peptidic sequence displayed aromatic α-amino acids due to the presence of CH-π interactions between the phenyl or indole ring and the methyl groups of the β-amino acid unit.

  5. Sources and pathways of polycyclic aromatic and saturated hydrocarbons in the Arkona Basin (Southern Baltic Sea, Central Europe)

    SciTech Connect

    Schulz, H.M.

    1996-12-31

    The Baltic Sea (Central Europe) is surrounded by coastal regions with long histories of industrialization. The heavy metal profiles in the sediments in the center of the Arkona Basin, one of the depressions of the southern Baltic Sea area, clearly reflect the historical anthropogenic influence. The Arkona Basin-is the final sink for materials derived from the Oder river which drains a highly polluted industrial area of Eastern Europe. Surficial muddy sediments from a close-meshed field of sampling-points were analyzed for distribution patterns of aliphatics and quantities and ratios of selected polycyclic aromatic hydrocarbons (PAH). These compounds are thought to reflect anthropogenic pollution related to emissions from traffic, heating, etc. We use these marker substances to test if the basin sediments reflect riverine input, and if additional sources can be identified.

  6. Méthodologie de l'extraction des hydrocarbures aromatiques polycycliques. Application à des sédiments de la lagune de Bizerte (Tunisie)Methodology of extraction of polycyclic aromatic hydrocarbons. Application to sediment from the Bizerte Lagoon (Tunisia)

    NASA Astrophysics Data System (ADS)

    Mzoughi, Nadia; Hellal, Fayçal; Dachraoui, Mohamed; Villeneuve, Jean-Pierre; Cattini, Chantal; de Mora, Stephen J.; El Abed, Amor

    2002-09-01

    The marine environment is very complex, with several important chemical, biological, and sedimentological interactions. Sediments constitute a reservoir for numerous pollutants, including polycyclic aromatic hydrocarbons (PAHs). PAHs are known by their mutagenic and/or carcinogenic effect. This study evaluates contamination levels in Bizerte Lagoon with respect to PAHs. The extraction efficiency of PAHs from sediment has been evaluated using Soxhlet or ultrasonic procedures, based on the recovery of an internal standard (9,10-dihydroanthracene). Several PAHs were found, including sixteen that are reported in the priority list of pollutants of the US Environmental Protection Agency (EPA). PAHs analysis was carried out by GC-FID and GC-MS for 16 samples sampled in two seasons: summer and winter. Results permit an assessment of PAHs pollution in the Bizerte Lagoon. To cite this article: N. Mzoughi et al., C. R. Geoscience 334 (2002) 893-901.

  7. CH-π "T-shape" interaction with histidine explains binding of aromatic galactosides to Pseudomonas aeruginosa lectin LecA.

    PubMed

    Kadam, Rameshwar U; Garg, Divita; Schwartz, Julian; Visini, Ricardo; Sattler, Michael; Stocker, Achim; Darbre, Tamis; Reymond, Jean-Louis

    2013-09-20

    The galactose specific lectin LecA mediates biofilm formation in the opportunistic pathogen P. aeruginosa . The interaction between LecA and aromatic β-galactoside biofilm inhibitors involves an intermolecular CH-π T-shape interaction between C(ε1)-H of residue His50 in LecA and the aromatic ring of the galactoside aglycone. The generality of this interaction was tested in a diverse family of β-galactosides. LecA binding to aromatic β-galactosides (KD ∼ 8 μM) was consistently stronger than to aliphatic β-galactosides (KD ∼ 36 μM). The CH-π interaction was observed in the X-ray crystal structures of six different LecA complexes, with shorter than the van der Waals distances indicating productive binding. Related XH/cation/π-π interactions involving other residues were identified in complexes of aromatic glycosides with a variety of carbohydrate binding proteins such as concanavalin A. Exploiting such interactions might be generally useful in drug design against these targets.

  8. Halides with Fifteen Aliphatic C–H···Anion Interaction Sites

    NASA Astrophysics Data System (ADS)

    Shi, Genggongwo; Aliakbar Tehrani, Zahra; Kim, Dongwook; Cho, Woo Jong; Youn, Il-Seung; Lee, Han Myoung; Yousuf, Muhammad; Ahmed, Nisar; Shirinfar, Bahareh; Teator, Aaron J.; Lastovickova, Dominika N.; Rasheed, Lubna; Lah, Myoung Soo; Bielawski, Christopher W.; Kim, Kwang S.

    2016-07-01

    Since the aliphatic C–H···anion interaction is relatively weak, anion binding using hydrophobic aliphatic C–H (Cali–H) groups has generally been considered not possible without the presence of additional binding sites that contain stronger interactions to the anion. Herein, we report X-ray structures of organic crystals that feature a chloride anion bound exclusively by hydrophobic Cali–H groups. An X-ray structure of imidazolium-based scaffolds using Cali–H···A‑ interactions (A‑ = anion) shows that a halide anion is directly interacting with fifteen Cali–H groups (involving eleven hydrogen bonds, two bidentate hydrogen-bond-type binding interactions and two weakly hydrogen-bonding-like binding interactions). Additional supporting interactions and/or other binding sites are not observed. We note that such types of complexes may not be rare since such high numbers of binding sites for an anion are also found in analogous tetraalkylammonium complexes. The Cali–H···A‑ interactions are driven by the formation of a near-spherical dipole layer shell structure around the anion. The alternating layers of electrostatic charge around the anion arise because the repulsions between weakly positively charged H atoms are reduced by the presence of the weakly negatively charged C atoms connected to H atoms.

  9. Trapping by amylose of the aliphatic chain grafted onto chlorogenic acid: importance of the graft position.

    PubMed

    Le-Bail, P; Lorentz, C; Pencreac'h, G; Soultani-Vigneron, S; Pontoire, B; López Giraldo, L J; Villeneuve, P; Hendrickx, J; Tran, V

    2015-03-06

    5-Caffeoylquinic acid (chlorogenic acid), is classified in acid-phenols family and as polyphenolic compounds it possesses antioxidant activity. The oxydative modification of chlorogenic acid in foods may lead to alteration of their qualities; to counteract these degradation effects, molecular encapsulation was used to protect chlorogenic acid. Amylose can interact strongly with a number of small molecules, including lipids. In order to enable chlorogenic acid complexation by amylose, a C16 aliphatic chain was previously grafted onto the cycle of quinic acid. This work showed that for the two lipophilic derivatives of chlorogenic acid: hexadecyl chlorogenate obtained by alkylation and 3-O-palmitoyl chlorogenic acid obtained by acylation; only the 3-O-palmitoyl chlorogenic acid complexed amylose. The chlorogenic acid derivatives were studied by X-ray diffraction, differential scanning calorimetry and NMR to elucidate the interaction. By comparing the results with previous work on the complexation of amylose by 4-O-palmitoyl chlorogenic acid, the importance of the aliphatic chain position on the cycle of the quinic acid is clearly highlighted. A study in molecular modeling helped to understand the difference in behavior relative to amylose of these three derivatives of chlorogenic acid.

  10. Far infrared spectra of solid state aliphatic amino acids in different protonation states.

    PubMed

    Trivella, Aurélien; Gaillard, Thomas; Stote, Roland H; Hellwig, Petra

    2010-03-21

    Far infrared spectra of zwitterionic, cationic, and anionic forms of aliphatic amino acids in solid state have been studied experimentally. Measurements were done on glycine, L-alanine, L-valine, L-leucine, and L-isoleucine powder samples and film samples obtained from dried solutions prepared at pH ranging from 1 to 13. Solid state density functional theory calculations were also performed, and detailed potential energy distributions were obtained from normal mode results. A good correspondence between experimental and simulated spectra was achieved and this allowed us to propose an almost complete band assignment for the far infrared spectra of zwitterionic forms. In the 700-50 cm(-1) range, three regions were identified, each corresponding to a characteristic set of normal modes. A first region between 700 and 450 cm(-1) mainly contained the carboxylate bending, rocking, and wagging modes as well as the ammonium torsional mode. The 450-250 cm(-1) region was representative of backbone and sidechain skeletal bending modes. At last, the low wavenumber zone, below 250 cm(-1), was characteristic of carboxylate and skeletal torsional modes and of lattice modes. Assignments are also proposed for glycine cationic and anionic forms, but could not be obtained for all aliphatic amino acids due to the lack of structural data. This work is intended to provide fundamental information for the understanding of peptides vibrational properties.

  11. Drude polarizable force field for aliphatic ketones and aldehydes, and their associated acyclic carbohydrates

    NASA Astrophysics Data System (ADS)

    Small, Meagan C.; Aytenfisu, Asaminew H.; Lin, Fang-Yu; He, Xibing; MacKerell, Alexander D.

    2017-02-01

    The majority of computer simulations exploring biomolecular function employ Class I additive force fields (FF), which do not treat polarization explicitly. Accordingly, much effort has been made into developing models that go beyond the additive approximation. Development and optimization of the Drude polarizable FF has yielded parameters for selected lipids, proteins, DNA and a limited number of carbohydrates. The work presented here details parametrization of aliphatic aldehydes and ketones (viz. acetaldehyde, propionaldehyde, butaryaldehyde, isobutaryaldehyde, acetone, and butanone) as well as their associated acyclic sugars (uc(d)-allose and uc(d)-psicose). LJ parameters are optimized targeting experimental heats of vaporization and molecular volumes, while the electrostatic parameters are optimized targeting QM water interactions, dipole moments, and molecular polarizabilities. Bonded parameters are targeted to both QM and crystal survey values, with the models for ketones and aldehydes shown to be in good agreement with QM and experimental target data. The reported heats of vaporization and molecular volumes represent a compromise between the studied model compounds. Simulations of the model compounds show an increase in the magnitude and the fluctuations of the dipole moments in moving from gas phase to condensed phases, which is a phenomenon that the additive FF is intrinsically unable to reproduce. The result is a polarizable model for aliphatic ketones and aldehydes including the acyclic sugars uc(d)-allose and uc(d)-psicose, thereby extending the available biomolecules in the Drude polarizable FF.

  12. Halides with Fifteen Aliphatic C–H···Anion Interaction Sites

    PubMed Central

    Shi, Genggongwo; Aliakbar Tehrani, Zahra; Kim, Dongwook; Cho, Woo Jong; Youn, Il-Seung; Lee, Han Myoung; Yousuf, Muhammad; Ahmed, Nisar; Shirinfar, Bahareh; Teator, Aaron J.; Lastovickova, Dominika N.; Rasheed, Lubna; Lah, Myoung Soo; Bielawski, Christopher W.; Kim, Kwang S.

    2016-01-01

    Since the aliphatic C–H···anion interaction is relatively weak, anion binding using hydrophobic aliphatic C–H (Cali–H) groups has generally been considered not possible without the presence of additional binding sites that contain stronger interactions to the anion. Herein, we report X-ray structures of organic crystals that feature a chloride anion bound exclusively by hydrophobic Cali–H groups. An X-ray structure of imidazolium-based scaffolds using Cali–H···A− interactions (A− = anion) shows that a halide anion is directly interacting with fifteen Cali–H groups (involving eleven hydrogen bonds, two bidentate hydrogen-bond-type binding interactions and two weakly hydrogen-bonding-like binding interactions). Additional supporting interactions and/or other binding sites are not observed. We note that such types of complexes may not be rare since such high numbers of binding sites for an anion are also found in analogous tetraalkylammonium complexes. The Cali–H···A− interactions are driven by the formation of a near-spherical dipole layer shell structure around the anion. The alternating layers of electrostatic charge around the anion arise because the repulsions between weakly positively charged H atoms are reduced by the presence of the weakly negatively charged C atoms connected to H atoms. PMID:27444513

  13. [Cloning and analysis of a new aliphatic amidase gene from Rhodococcus erythropolis TA37].

    PubMed

    Lavrov, K V; Karpova, I Yu; Epremyan, A S; Yanenko, A S

    2014-10-01

    A new aliphatic amidase gene (ami), having a level of similarity with the nearest homologs of no more than 77%, was identified in the Rhodococcus erythropolis TA37 strain, which is able to hydrolyze a wide range of amides. The amidase gene was cloned within a 3.7 kb chromosomal locus, which also contains putative acetyl-CoA ligase and ABC-type transportergenes. The structure of this locus in the R. erythropolis TA37 strain differs from the structure of loci in other Rhodococcus strains. The amidase gene is expressed in Escherichia coli cells. It was demonstrated that amidase (generated in the recombinant strain) efficiently hydrolyzes acetamide (aliphatic anmide) and does not use 4'-nitroacetanilide (N-substituted amide) as a substrate. Insertional inactivation of the amidase gene in the R. erythropolis TA37 strain results in a considerable decrease (by at least 6-7 times) in basal amidase activity, indicating functional amidase activity in the R. erythropolis TA37 strain.

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

    PubMed

    Ito, Kazuaki; Sakamoto, Jun; Nagaoka, Kazuya; Takayama, Yohichi; Kanahori, Takashi; Sunahara, Hiroshi; Hayashi, Tsuneo; Sato, Shinji; Hirokawa, Takeshi; Tanaka, Kazuhiko

    2012-04-01

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

  15. The distribution and sources of polycyclic aromatic hydrocarbons in surface sediments along the Egyptian Mediterranean coast.

    PubMed

    El Nemr, Ahmed; Said, Tarek O; Khaled, Azza; El-Sikaily, Amany; Abd-Allah, Aly M A

    2007-01-01

    Coastal marine sediment samples were collected from 31 sampling stations along the Egyptian Mediterranean Sea coast. All sediment samples were analyzed to determine aliphatic and polycyclic aromatic hydrocarbons (PAHs) as well as total organic carbon (TOC) contents and grain size analysis. Total concentrations of 16 EPA-PAHs in the sediments were varied from 88 to 6338 ng g(-1) with an average value of 154 ng g(-1) (dry weight). However, the concentrations of total aliphatic were varied from 1.3 to 69.9 ng g(-1) with an average value of 15.6 ng g(-1) (dry weight). The highest contents of PAHs were found in the Eastern harbor (6338 ng g(-1)), Manzala (5206 ng g(-1)) and El-Jamil East (4895 ng g(-1)) locations. Good correlations observed between a certain numbers of PAH concentrations allowed to identify its origin. The average total organic carbon (TOC) percent was varied from 0.91 to 4.54%. Higher concentration of total pyrolytic hydrocarbons ( summation operatorCOMB) than total fossil hydrocarbons ( summation operatorPHE) declared that atmospheric fall-out is the significant source of PAHs to marine sediments of the Egyptian Mediterranean coast. The selected marked compounds, a principal component analysis (PCA) and special PAHs compound ratios (phenanthrene/anthracene vs fluoranthene/pyrene; summation operatorCOMB/ summation operatorEPA-PAHs) suggest the pyrogenic origins, especially traffic exhausts, are the dominant sources of PAHs in most locations. Interferences of rather petrogenic and pyrolytic PAH contaminations were noticed in the harbors due to petroleum products deliveries and fuel combustion emissions from the ships staying alongside the quays.

  16. In vitro evaluation of aliphatic fatty alcohol metabolites of Perseaamericana seed as potential antimalarial and antimicrobial agents

    PubMed Central

    Falodun, A.; Erharuyi, O.; Imieje, V.; Ahomafor, J.; Akunyuli, C.; Jacobs, M.; Khan, S.; Hamann, M. T.; Langer, P.

    2016-01-01

    Perseaamericana Mill (Lauraceae) is a local medicinal plant used in Nigerian ethnomedicine as antimalarial. The aqueous decoction of the root part is a potent remedy against bacterial infections. Hence, the need to investigate the phytochemical and biological activities (antimicrobial and antiplasmodial) of the root back of Perseaamericana. Chromatographic and spectroscopic techniques were used in the identification and purification of metabolites, which were assayed for antimalarial and antimicrobial activities using Plasmodium falciparum and a panel of microorganisms. From the seeds of P. americana, five known 1, 2, 4-dihydroxy derivatives aliphatic alcohols, called avocadenols were isolated and identified by spectroscopic methods including 1D- and 2D NMR, and comparison with reported data in literature. Antifungal activity for 1, 2, 4-Trihydroxyheptadec-6-en-16-yne (5) (IC50< 8 μg/mL) against all the fungal strains and S. areus, and antimalarial activity for compounds 1, 2, 4-Trihydroxyheptadec-16-ene (1) and 1, 2, 4-tetrahydroxyheptadecane-6, 16-diene(2) (IC50 = 1.6 and 1.4 μg/mL for the D6 clone, respectively, and 2.1 and 1.4 μg/mL for the W2 clone, respectively) was observed. The fatty alcohols 1, 2, 4-tetrahydroxyheptadecane-6, 16-diene(2); 1, 2, 4-Trihydroxyheptadec-16-yne(3) and 1, 2, 4-Trihydroxyheptadecane(4) also exhibited promising in vitro antibacterial activity against a panel of pathogenic bacteria S. areus, methicillin resistant S. areus and E. coli at IC50 values of 21.1, 8, 200 μg/mL), (3.259, 86.32 μg/mL) and (17.18, 8.26 and 200 μg/mL), respectively. The results of this study provide evidence that the fatty alcohols are a promising class of antimalarial and antimicrobial agents. PMID:28042193

  17. 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

  18. 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.

  19. The modulation of the DNA-damaging effect of polycyclic aromatic agents by xanthines. Part I. Reduction of cytostatic effects of quinacrine mustard by caffeine.

    PubMed

    Kapuscinski, Jan; Ardelt, Barbara; Piosik, Jacek; Zdunek, Malgorzata; Darzynkiewicz, Zbigniew

    2002-02-15

    Recently, accumulated statistical data indicate the protective effect of caffeine consumption against several types of cancer diseases. There are also reports about protective effect of caffeine and other xanthines against tumors induced by polycyclic aromatic hydrocarbons. One of the explanations is based on biological activation of such carcinogens by cytochromes that are also known for metabolism of caffeine. However, there is also numerous data indicating reverse effect on cytotoxicity of anticancer drugs that inhibit the action of topoisomerase I (e.g. Camptothecin or Topotecan) and topoisomerase II inhibitors (e.g. Doxorubicin, Mitoxantrone or mAMSA). In this work we tested the hypothesis that the caffeine protective effect is the result of sequestering of aromatic mutagens by formation of stacking (pi-pi) complexes. As the models for the study we have chosen two well-known mutagens, that do not require metabolical activation: quinacrine mustard(QM, aromatic, heterocyclic nitrogen mustard) and mechlorethamine (NM2, aliphatic nitrogen mustard). The flow cytometry study of these agents' action on the cell cycle of HL-60 cells indicated that caffeine prevents the cytotoxic action of QM, but not that of NM2. The formations of stacking complexes of QM with caffeine were confirmed by light absorption, calorimetric measurements and by molecular modeling calculation. Using the statistical thermodynamics calculations we calculated the "neighborhood" association constant (K(AC)=59+/-2M(-1)) and enthalpy change (DeltaH(0')=-116cal mol(-1)); the favorable entropy change of complex formation (DeltaS(0')=7.72cal mol(-1)K(-1), due to release of several water molecules, associated with components in the process of complex formation). The Gibbs' free energy change of QM-CAF formation is DeltaG(0')=-2.41kcal mol(-1). We were unable to detect any interaction between NM2 and caffeine either by spectroscopic or calorimetric measurement. In order to establish, whether the

  20. On the inclusion of alkanes into the monolayer of aliphatic alcohols at the water/alkane vapor interface: a quantum chemical approach.

    PubMed

    Vysotsky, Yuri B; Fomina, Elena S; Belyaeva, Elena A; Fainerman, Valentin B; Vollhardt, Dieter

    2013-02-14

    In the framework of the quantum chemical semiempirical PM3 method thermodynamic and structural parameters of the formation and clusterization of aliphatic alcohols C(n)H(2n+1)OH (n(OH) = 8-16) at 298 K at the water/alkane vapor C(n)H(2n+2), (n(CH(3)) = 6-16) interface were calculated. The dependencies of enthalpy, entropy and Gibbs' energy of clusterization per one monomer molecule of 2D films on the alkyl chain length of corresponding alcohols and alkanes, the molar fraction of alkanes in the monolayers and the immersion degree of alcohol molecules into the water phase were shown to be linear or stepwise. The threshold of spontaneous clusterization of aliphatic alcohols at the water/alkane vapor interface was 10-11 carbon atoms at 298 K which is in line with experimental data at the air/water interface. It is shown that the presence of alkane vapor does not influence the process of alcohol monolayer formation. The structure of these monolayers is analogous to those obtained at the air/water interface in agreement with experimental data. The inclusion of alkane molecules into the amphiphilic monolayer at the water/alkane vapor interface is possible for amphiphiles with the spontaneous clusterization threshold at the air/water interface (n(s)(0)) of at least 16 methylene units in the alkyl chain, and it does not depend on the molar fraction of alkanes in the corresponding monolayer. The inclusion of alkanes from the vapor phase into the amphiphilic monolayer also requires that the difference between the alkyl chain lengths of alcohols and alkanes is not larger than n(s)(0) - 15 and n(s)(0) - 14 for the 2D film 1 and 2D film 2, respectively.

  1. The Infrared Spectra of Polycyclic Aromatic Hydrocarbons with Excess Peripheral H Atoms (H(sub n)-PAHs) and their Relation to the 3.4 and 6.9 Micrometer PAH Emission Features

    NASA Technical Reports Server (NTRS)

    Sandford, Scott A.; Bernstein, Max P.; Materese, Christopher K.

    2013-01-01

    A population of polycyclic aromatic hydrocarbons (PAHs) and related materials are thought to be responsible for the family of infrared emission features that are seen towards a wide variety of astrophysical environments. A potentially important subclass of these materials are polycyclic aromatic hydrocarbons whose edges contain excess H atoms (H(sub n)-PAHs). While it has been suggested that this type of compound may be present in the interstellar population, it has been difficult to properly assess this possibility because of a lack of suitable infrared laboratory spectra to assist with analysis of the astronomical data. We present the 4000-500 cm(exp -1) (2.5-20 micrometers) infrared spectra of 23 H(sub n)-PAHs and related molecules isolated in argon matrices, under conditions suitable for use in the interpretation of astronomical data. The spectra of molecules with mixed aromatic and aliphatic domains show unique characteristics that distinguish them from their fully aromatic PAH equivalents. We discuss the changes to the spectra of these types of molecules as they transition from fully aromatic to fully aliphatic forms. The implications for the interpretation of astronomical spectra are discussed with specific emphasis on the 3.4 and 6.9 micrometer features. Laboratory data is compared with emission spectra from IRAS 21282+5050, an object with normal PAH emission features, in addition to IRAS 22272+5435 and IRAS 0496+3429, two protoplanetary nebulae with abnormally large 3.4 micrometer features. We show that 'normal' PAH emission objects contain relatively few H(sub n)-PAHs in their emitter populations, but less evolved protoplanetary nebulae may contain significant abundances of these molecules.

  2. Direct photolysis of polycyclic aromatic hydrocarbons in drinking water sources.

    PubMed

    Sanches, S; Leitão, C; Penetra, A; Cardoso, V V; Ferreira, E; Benoliel, M J; Crespo, M T Barreto; Pereira, V J

    2011-09-15

    The widely used low pressure lamps were tested in terms of their efficiency to degrade polycyclic aromatic hydrocarbons listed as priority pollutants by the European Water Framework Directive and the U.S. Environmental Protection Agency, in water matrices with very different compositions (laboratory grade water, groundwater, and surface water). Using a UV fluence of 1500 mJ/cm(2), anthracene and benzo(a)pyrene were efficiently degraded, with much higher percent removals obtained when present in groundwater (83-93%) compared to surface water (36-48%). The removal percentages obtained for fluoranthene were lower and ranged from 13 to 54% in the different water matrices tested. Several parameters that influence the direct photolysis of polycyclic aromatic hydrocarbons were determined and their photolysis by-products were identified by mass spectrometry. The formation of photolysis by-products was found to be highly dependent on the source waters tested.

  3. Phylogenetic comparison of two polycyclic aromatic hydrocarbon-degrading mycobacteria.

    PubMed Central

    Govindaswami, M; Feldhake, D J; Kinkle, B K; Mindell, D P; Loper, J C

    1995-01-01

    Two mycobacterial strains previously isolated from fossil-fuel-contaminated environments and shown to degrade four- and/or five-ring polycyclic aromatic hydrocarbons were further characterized. The two strains, PYR-I and RJGII-135, had similar growth characteristics, colony morphologies, and scotochromogenic pigmentations. DNA amplification fingerprints obtained with total genomic DNA indicated some strain similarities but with several distinctly different bands. Moreover, phylogenetic analysis based upon essentially full-length 16S rRNA gene sequences separates the two strains as distinct species within the fast-growing group of mycobacteria. Although both strains are thermosensitive, strain PYR-I has the bulged U between positions 184 and 193 characteristic of thermotolerant mycobacteria. Both strains are of potential use for reintroduction into and bioremediation of polycyclic aromatic hydrocarbon-contaminated soils. PMID:7574631

  4. Phylogenetic comparison of two polycyclic aromatic hydrogen-degrading mycobacteria

    SciTech Connect

    Govindaswami, M.; Loper, J.C.; Feldhake, D.J.

    1995-09-01

    Two mycobacterial strains previously isolated from fossil-fuel-contaminated environments and shown to degrade four- and/or five-ring polycyclic aromatic hydrocarbons were further characterized. The two strains, PYR-I and RJGII-135, had similar growth characteristics, colony morphologies, and scotochromogenic pigmentations. DNA amplification fringerprints obtained with total genomic DNA indicated some strain similarities but with several distinctly different bands. Moreover, phylogenetic analysis based upon essentially full-length 16S rRNA gene sequences separates the two strains as distinct species within the fast-growing group of mycobacteria. Although both strains are thermosensitive, strain PYR-I has the bulged U between positions 184 and 193 characteristic of thermotolerant mycobacteria. Both strains are of potential use for reintroduction into and bioremediation of polycyclic aromatic hydrocarbon-contaminated soils. 26 refs., 4 figs., 1 tab.

  5. 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

  6. Production of aromatics in Saccharomyces cerevisiae--a feasibility study.

    PubMed

    Krömer, Jens O; Nunez-Bernal, Dariela; Averesch, Nils J H; Hampe, Jennifer; Varela, Javier; Varela, Cristian

    2013-01-20

    Aromatics are amongst the most important bulk feedstocks for the chemical industry, however, no viable bioprocess exists today and production is still dependent on petro-chemistry. In this article the production of aromatic precursors such as p-hydroxybenzoic acid (PHBA) and p-amino benzoic acid (PABA) in Saccharomyces cerevisiae was evaluated using metabolic network analysis. Theoretical mass yields for PHBA and for PABA obtained by metabolic network analysis were 0.58 and 0.53 g g(glucose)⁻¹, respectively. A major setback for microbial production of aromatics is the high toxicity of the products. Therefore, PHBA and PABA toxicity was evaluated in S. cerevisiae. Minimal inhibitory concentrations of 38.3 g L⁻¹ for PHBA and 0.62 g L⁻¹ for PABA were observed. However, PABA toxicity could be alleviated in adaptation experiments. Finally, metabolic engineering was used to create proof of principle first generation strains of S. cerevisiae. Overall accumulation of 650 μM PHBA and 250 μM PABA could be achieved.

  7. A Bioinspired Catalytic Aerobic Oxidative C–H Functionalization of Primary Aliphatic Amines: Synthesis of 1,2-Disubstituted Benzimidazoles

    PubMed Central

    Nguyen, Khac Minh Huy; Largeron, Martine

    2015-01-01

    Aerobic oxidative C–H functionalization of primary aliphatic amines has been accomplished with a biomimetic cooperative catalytic system to furnish 1,2-disubstituted benzimidazoles that play an important role as drug discovery targets. This one-pot atom-economical multistep process, which proceeds under mild conditions, with ambient air and equimolar amounts of each coupling partner, constitutes a convenient environmentally friendly strategy to functionalize non-activated aliphatic amines that remain challenging substrates for non-enzymatic catalytic aerobic systems. PMID:26206475

  8. Estimating the physicochemical properties of polyhalogenated aromatic and aliphatic compounds using UPPER: part 2. Aqueous solubility, octanol solubility and octanol-water partition coefficient.

    PubMed

    Admire, Brittany; Lian, Bo; Yalkowsky, Samuel H

    2015-01-01

    The UPPER (Unified Physicochemical Property Estimation Relationships) model uses additive and non-additive parameters to estimate 20 biologically relevant properties of organic compounds. The model has been validated by Lian and Yalkowsky (2014) on a data set of 700 hydrocarbons. Recently, Admire et al. (2014) expanded the model to predict the boiling and melting points of 1288 polyhalogenated benzenes, biphenyls, dibenzo-p-dioxins, diphenyl ethers, anisoles and alkanes. In this work, 19 new group descriptors are determined and used to predict the aqueous solubilities, octanol solubilities and the octanol-water coefficients.

  9. Synthesis, spectral, crystallography and thermal investigations of novel Schiff base complexes of manganese (III) derived from heterocyclic beta-diketone with aromatic and aliphatic diamine.

    PubMed

    Surati, Kiran R; Thaker, B T

    2010-01-01

    The Schiff base tetradentate ligands N,N-bis-(3,5-dimethyl-1-p-tolyl-1H-pyrazol-4-ylmethylene)-ethane-1,2-diamine (H(2)L(1)), N,N-bis-(3,5-dimethyl-1-p-sulfonyl-1H-pyrazol-4-ylmethylene)-ethane-1,2-diamine (H(2)L(2)), N,N-bis-(3,5-dimethyl-1-p-tolyl-1H-pyrazol-4-ylmethylene)-benzene-1,2-diamine (H(2)L(3)) and N,N-bis-(3,5-dimethyl-1-p-sulfonyl-1H-pyrazol-4-ylmethylene)-benzene-1,2-diamine (H(2)L(4)) were prepared from the reaction between 5-oxo-3-methyl-1-p-tolyl-1H-pyrazole-4-carbaldehyde or 4-(4-formyl-5-oxo-3-methyl-pyrazol-1-yl)-benzenesulfonic acid and o-phenylenediamine or ethylenediamine. And these are characterized by elemental analysis, FT-IR, (1)H NMR and GC-MS. The corresponding Schiff base complexes of Mn(III) were prepared by condensation of [Mn(3)(mu(3)-O)(OAc)(6)(H(2)O)(3)].3H(2)O with ligands H(2)L(1), H(2)L(2), H(2)L(3) and H(2)L(4). All these complexes have been characterized by elemental analysis, magnetic susceptibility, X-ray crystallography, conductometry measurement, FT-IR, electronic spectra and mass (FAB) spectrometry. Thermal behaviour of the complexes has been studied by TGA, DTA and DSC. Electronic spectra and magnetic susceptibility measurements indicate octahedral stereochemistry of manganese (III) complexes, while non-electrolytic behaviour complexes indicate the absence of counter ion.

  10. Synthesis, spectral, crystallography and thermal investigations of novel Schiff base complexes of manganese (III) derived from heterocyclic β-diketone with aromatic and aliphatic diamine

    NASA Astrophysics Data System (ADS)

    Surati, Kiran R.; Thaker, B. T.

    2010-01-01

    The Schiff base tetradentate ligands N,N-bis-(3,5-dimethyl-1-p-tolyl-1H-pyrazol-4-ylmethylene)-ethane-1,2-diamine (H 2L 1), N,N-bis-(3,5-dimethyl-1-p-sulfonyl-1H-pyrazol-4-ylmethylene)-ethane-1,2-diamine (H 2L 2), N,N-bis-(3,5-dimethyl-1-p-tolyl-1H-pyrazol-4-ylmethylene)-benzene-1,2-diamine (H 2L 3) and N,N-bis-(3,5-dimethyl-1-p-sulfonyl-1H-pyrazol-4-ylmethylene)-benzene-1,2-diamine (H 2L 4) were prepared from the reaction between 5-oxo-3-methyl-1-p-tolyl-1H-pyrazole-4-carbaldehyde or 4-(4-formyl-5-oxo-3-methyl-pyrazol-1-yl)-benzenesulfonic acid and o-phenylenediamine or ethylenediamine. And these are characterized by elemental analysis, FT-IR, 1H NMR and GC-MS. The corresponding Schiff base complexes of Mn(III) were prepared by condensation of [Mn 3(μ 3-O)(OAc) 6(H 2O) 3]·3H 2O with ligands H 2L 1, H 2L 2, H 2L 3 and H 2L 4. All these complexes have been characterized by elemental analysis, magnetic susceptibility, X-ray crystallography, conductometry measurement, FT-IR, electronic spectra and mass (FAB) spectrometry. Thermal behaviour of the complexes has been studied by TGA, DTA and DSC. Electronic spectra and magnetic susceptibility measurements indicate octahedral stereochemistry of manganese (III) complexes, while non-electrolytic behaviour complexes indicate the absence of counter ion.

  11. Quantiative determination of sulfonated aliphatic and aromatic surfactants in sewage sludge by ion-pair/supercritical fluid extraction and derivatization gas chromatography/mass spectrometry

    SciTech Connect

    Field, J.A.; Field, T.M.; Giger, W. ); Miller, D.J.; Hawthorne, S.B. )

    1992-12-15

    Secondary alkanesulfonate (SAS) and linear alkylbenzene-sulfonate (LAS) surfactants were quantitatively (> 90%) extracted from sewage sludges as their tetrabutylammonium ion pairs using 400 atm of supercritical CO[sub 2] for 5 min of static extraction followed by 10 min of dynamic extraction at 80[degrees]C. Ion pairs of SAS and LAS quantitatively formed butyl esters in the injection port of the gas chromatograph and were determined by gas chromatography/mass spectrometry without class fractionation of the sewage sludge extracts. Concentrations of SAS and LAS in sludges from five different sewage treatment plants ranged from 0.27 to 0.80 g/kg of dry sewage sludge and from 3.83 to 7.51 g/kg, respectively. Good reproducibility was achieved with RSDs of typically 5% for replicate extractions and analyses. Homologue and isomer distributions of SAS in sewage sludge indicated an enrichment of the more hydrophobic components in sewage sludge during sewage treatment. 25 refs., 5 figs., 5 tabs.

  12. Spatial distribution and composition of aliphatic hydrocarbons, polycyclic aromatic hydrocarbons and hopanes in superficial sediments of the coral reefs of the Persian Gulf, Iran.

    PubMed

    Ali, Ranjbar Jafarabadi; Alireza, Riyahi Bakhtiari; Mansour, Aliabadian; Amirhossein, Shadmehri Toosi

    2017-02-16

    This study is the first quantitative report on petroleum biomarkers from the coral reefs systems of the Persian Gulf. 120 reef surface sediment samples from ten fragile coral reef ecosystems were collected and analyzed for grain size, biogenic elements, elemental ratios, and petroleum biomarkers (n-alkanes, PAHs(1) and Hopanes) to assess the sources and early diagenesis of sedimentary organic matter. The mean grain size of the reef sediments ranged from 13.56 to 37.11% (Clay), 26.92 to 51.73% (Sand) and 35.97 to 43.85% (Silt). TOC(2) (3.35-9.72 mg.g(-1)) and TON(3) (0.4-1.10 mg.g(-1)) were identified as influencing factors on the accumulation of petroleum hydrocarbons, whilst BC(4) (1.08-3.28 mg.g(-1)) and TIN(5) (0.13-0.86) did not exhibit any determining effect. Although BC and TIN demonstrated heterogeneous spatial distribution, TOC and TON indicated homogenous distribution with continually upward trend in concentration from the east to west ward of the Gulf. The mean calculated TOC/TN ratios vacillated according to the stations (p < 0.05) from 2.96 at Shidvar Island to 8.64 at Hengam Island. The high TOC/TN ratios were observed in the Hengam (8.64), Kharg (8.04) and Siri (6.29), respectively, suggesting a predominant marine origin. The mean concentrations of ∑C11-35n-alkanes, ∑30 PAHs and ∑9Hopanes were found in the ranges of 385-937 μg.g(-1)dw, (overall mean:590 μg.g(-1)dw), 326-793 ng.g(-1)dw (499 ng.g(-1)dw), 88 to 568 μg.g(-1) d (258 ng.g(-1)dw), respectively. Higher concentrations of detected petroleum biomarkers in reef sediments were chiefly distributed near main industrial areas, Kharg, Lavan and Siri, whilst the lower concentrations were in Hormoz and Qeshm. In addition, one-way ANOVA(6) analysis demonstrated considerably significant differences (p < 0.05) among concentration of detected total petroleum hydrocarbons between most sampling locations. Some sampling sites especially Kharg, Lavan, Siri and Lark indicated higher concentration of n-alkanes due to the higher maintenance of organic matter by high clay content in the sediments. Furthermore, most sediment samples, except for Hormoz, Qeshm and Hengam showed an even carbon preference for n-alkanes which could be correlated to bacterial input. NPMDS(7) analysis also demonstrated that among the congeners of petroleum biomarkers, n-C12,n-C14, n-C16,n-C18 and n-C20 for n-alkanes, Phe(8) and Naph(9) along with their Alkyl homologues for PAHs (2-3 rings accounted for 60%) and C30αβ and C29αβ for Hopanes were discriminated from their other congeners in the whole study area. Our results based on the PCA(10) analysis and diagnostic indices of AHs(11) and PAHs along with ring classification of PAHs, in addition, the ubiquitous presence of UCM,(12) and Hopanes revealed that the main sources of the pollution were petroleum and petroleum combustion mainly from offshore oil exploration and extraction, discharge of pollutants from shipping activities.

  13. Sediment-Associated Reactions of Aromatic Amines

    EPA Science Inventory

    Sorption of aromatic amines to sediments and soils can occur by both reversible physical processes and irreversible chemical processes. To elucidate the significance of these sorption pathways, the sorption kinetics of aniline and pyridine were studied in resaturated pond sedimen...

  14. 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.

  15. Infrared Spectra of Polycyclic Aromatic Hydrocarbons (PAHs)

    NASA Technical Reports Server (NTRS)

    Bauschlicher, Charles W., Jr.; Bakes, E. L. O.

    2000-01-01

    We have computed the synthetic infrared spectra of some polycyclic aromatic hydrocarbons containing up to 54 carbon atoms. The species studied include ovalene, circumcoronene, dicoronylene, and hexabenzocoronene. We report spectra for anions, neutrals, cations, and multiply charged cations.

  16. Polycyclic Aromatic Hydrocarbons with SPICA

    NASA Astrophysics Data System (ADS)

    Berné, O.; Joblin, C.; Mulas, G.; Tielens, A. G. G. M.; Goicoechea, J. R.

    2009-12-01

    Thanks to high sensitivity, high angular resolution and broad spectral coverage, SPICA will offer a unique opportunity to better characterize the nature of polycyclic aromatic hydrocarbons (PAHs) and very small grains (VSGs), to better use them as probes of astrophysical environments. The angular resolution will enable to probe the chemical frontiers in the evolution process from VSGs to neutral PAHs, to ionized PAHs and to "Grand-PAHs" in photodissotiation regions and HII regions, as a function of G0 /n (UV radiation field / density). High sensitivity will favor the detection of the far-IR skeletal emission bands of PAHs, which provide specific fingerprints and could lead to the identification of individual PAHs. This overall characterization will allow to use PAH and VSG populations as tracers of physical conditions in spatially resolved protoplanetary disks and nearby galaxies (using mid-IR instruments), and in high redshift galaxies (using the far-IR instrument), thanks to the broad spectral coverage SPICA provides. Based on our previous experience with ISO and Spitzer we discuss how these goals can be reached.

  17. Flexible backbone aromatic polyimide adhesives

    NASA Technical Reports Server (NTRS)

    Progar, Donald J.; St. Clair, Terry L.

    1989-01-01

    Continuing research at Langley Research Center on the synthesis and development of new inexpensive flexible aromatic polyimides as adhesives has resulted in a material identified as LARC-F-SO2 with similarities to polyimidesulfone, PISO2, and other flexible backbone polyimides recently reported by Progar and St. Clair. Also prepared and evaluated was an endcapped version of PISO2. These two polymers were compared with LARC-TPI and LARC-STPI, polyimides research in our laboratory and reported in the literature. The adhesive evaluation, primarily based on lap shear strength (LSS) tests at RT, 177 C and 204 C, involved preparing adhesive tapes, conducting bonding studies and exposing lap shear specimens to 204 C air for up to 1000 hrs and to a 72-hour water boil. The type of adhesive failure as well as the Tg was determined for the fractured specimens. The results indicate that LARC-TPI provides the highest LSSs. LARC-F-SO2, LARC-TPI and LARC-STPI all retain their strengths after thermal exposure for 1000 hrs and PISO2 retains greater than 80 percent of its control strengths. After a 72-hr water boil exposure, most of the four adhesive systems showed reduced strengths for all test temperatures although still retaining a high percentage of their original strength (greater than 60 percent) except for one case. The predominant failure type was cohesive with no significant change in the Tgs.

  18. Flexible backbone aromatic polyimide adhesives

    NASA Technical Reports Server (NTRS)

    Progar, Donald J.; St.clair, Terry L.

    1988-01-01

    Continuing research at Langley Research Center on the synthesis and development of new inexpensive flexible aromatic polyimides as adhesives has resulted in a material identified as LARC-F-SO2 with similarities to polyimidesulfone, PISO2, and other flexible backbone polyimides recently reported by Progar and St. Clair. Also prepared and evaluated was an endcapped version of PISO2. These two polymers were compared with LARC-TPI and LARC-STPI, polyimides research in our laboratory and reported in the literature. The adhesive evaluation, primarily based on lap shear strength (LSS) tests at RT, 177 C and 204 C, involved preparing adhesive tapes, conducting bonding studies and exposing lap shear specimens to 204 C air for up to 1000 hrs and to a 72-hour water boil. The type of adhesive failure as well as the Tg was determined for the fractured specimens. The results indicate that LARC-TPI provides the highest LSSs. LARC-F-SO2, LARC-TPI and LARC-STPI all retain their strengths after thermal exposure for 1000 hrs and PISO2 retains greater than 80 percent of its control strengths. After a 72-hr water boil exposure, most of the four adhesive systems showed reduced strengths for all test temperatures although still retaining a high percentage of their original strength (greater than 60 percent) except for one case. The predominant failure type was cohesive with no significant change in the Tgs.

  19. An Aromatic Inventory of the Local Volume

    NASA Astrophysics Data System (ADS)

    Marble, A. R.; Engelbracht, C. W.; van Zee, L.; Dale, D. A.; Smith, J. D. T.; Gordon, K. D.; Wu, Y.; Lee, J. C.; Kennicutt, R. C.; Skillman, E. D.; Johnson, L. C.; Block, M.; Calzetti, D.; Cohen, S. A.; Lee, H.; Schuster, M. D.

    2010-05-01

    Using infrared photometry from the Spitzer Space Telescope, we perform the first inventory of aromatic feature emission (also commonly referred to as polycyclic aromatic hydrocarbon emission) for a statistically complete sample of star-forming galaxies in the local volume. The photometric methodology involved is calibrated and demonstrated to recover the aromatic fraction of the Infrared Array Camera 8 μm flux with a standard deviation of 6% for a training set of 40 SINGS galaxies (ranging from stellar to dust dominated) with both suitable mid-infrared Spitzer Infrared Spectrograph spectra and equivalent photometry. A potential factor of 2 improvement could be realized with suitable 5.5 μm and 10 μm photometry, such as what may be provided in the future by the James Webb Space Telescope. The resulting technique is then applied to mid-infrared photometry for the 258 galaxies from the Local Volume Legacy (LVL) survey, a large sample dominated in number by low-luminosity dwarf galaxies for which obtaining comparable mid-infrared spectroscopy is not feasible. We find the total LVL luminosity due to five strong aromatic features in the 8 μm complex to be 2.47 × 1010 L sun with a mean volume density of 8.8 × 106 L sun Mpc-3. Twenty-four of the LVL galaxies, corresponding to a luminosity cut at MB = -18.22, account for 90% of the aromatic luminosity. Using oxygen abundances compiled from the literature for 129 of the 258 LVL galaxies, we find a correlation between metallicity and the aromatic-to-total infrared emission ratio but not the aromatic-to-total 8 μm dust emission ratio. A possible explanation is that metallicity plays a role in the abundance of aromatic molecules relative to the total dust content, but other factors, such as star formation and/or the local radiation field, affect the excitation of those molecules.

  20. Extreme Modulation Properties of Aromatic Fluorine

    SciTech Connect

    Burnett, Michael N; Gakh, Andrei A

    2011-01-01

    Thorough examination of the current literature as well as publicly available databases allowed us to qualify aromatic fluorine as a unique modulator of biological properties of organic compounds. In some rare cases, introduction of fluorine increased biological activity 100,000 times and even higher. We have also identified several examples where aromatic fluorine substantially reduced biological activity. Selected individual cases of extreme modulation are presented and discussed in the paper.