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Sample records for alkylated aromatics

  1. Alkyl polycyclic aromatic hydrocarbons emissions in diesel/biodiesel exhaust

    Science.gov (United States)

    Casal, Carina S.; Arbilla, Graciela; Corrêa, Sergio M.

    2014-10-01

    Polycyclic aromatic hydrocarbons (PAHs) are widely studied in environmental matrices, such as air, water, soil and sediment, because of their toxicity, mutagenicity and carcinogenicity. Because of these properties, the environmental agencies of developed countries have listed sixteen PAHs as priority pollutants. Few countries have limits for these compounds for ambient air, but they only limit emissions from stationary and mobile sources and occupational areas. There are several studies to specifically address the 16 priority PAHs and very little for the alkyl PAHs. These compounds are more abundant, more persistent and frequently more toxic than the non-alkylated PAHs, and the toxicity increases with the number of alkyl substitutions on the aromatic ring. In this study, a method was developed for the analysis of PAHs and alkyl PAHs by using a GC-MS and large injection volume injection coupled with program temperature vaporisation, which allows for limits of detection below 1.0 ng μL-1. Several variables were tested, such as the injection volume, injection velocity, injector initial temperature, duration of the solvent split and others. This method was evaluated in samples from particulate matter from the emissions of engines employing standard diesel, commercial diesel and biodiesel B20. Samples were collected on a dynamometer bench for a diesel engine cycle and the results ranged from 0.5 to 96.9 ng mL-1, indicating that diesel/biodiesel makes a significant contribution to the formation of PAHs and alkyl PAHs.

  2. Distributions of polycyclic aromatic hydrocarbons and alkylated polycyclic aromatic hydrocarbons in Osaka Bay, Japan

    International Nuclear Information System (INIS)

    Highlights: • Contamination of sediment by PAHs and alkylated PAHs was investigated in Osaka Bay. • The major sources appeared to be pyrogenic or both pyrogenic and petrogenic. • PAH concentrations were remarkably high at a site near Kobe. • PAHs in Kobe may have been derived from the fire associated with the earthquake. - Abstract: Contaminations in sediments by polycyclic aromatic hydrocarbons (PAHs) and alkylated PAHs were investigated at 44 sites in Osaka Bay, Japan. Concentrations of total PAHs and alkylated PAHs were in the range 6.40–7800 ng/g dry weights and 13.7–1700 ng/g dry weights, respectively. The PAH concentrations tended to be higher along the shoreline in the vicinities of big ports, industrialized areas, and densely populated regions such as the cities of Osaka and Kobe. The major sources appeared to be pyrogenic or both pyrogenic and petrogenic at most of the sites. PAH concentrations were remarkably high at a site near Kobe, where the concentrations of dibenzo(a,h)anthracene and benzo(g,h,i)perylene exceeded the effects-range-medium concentration and eight PAHs were above the corresponding effects-range-low concentrations. Those PAHs may have been derived from the great fire associated with the large earthquake in 1995

  3. Polycyclic Aromatic Acids Are Primary Metabolites of Alkyl-PAHs-A Case Study with Nereis diversicolor.

    Science.gov (United States)

    Malmquist, Linus M V; Selck, Henriette; Jørgensen, Kåre B; Christensen, Jan H

    2015-05-01

    Although concentrations of alkylated polycyclic aromatic hydrocarbons (alkyl-PAHs) in oil-contaminated sediments are higher than those of unsubstituted PAHs, only little attention has been given to metabolism and ecotoxicity of alkyl-PAHs. In this study we demonstrated that metabolism of alkyl-PAHs primarily forms polycyclic aromatic acids (PAAs). We generalize this to other alkyl-PAHs, based on literature and the present study of the metabolism of 1-methylphenanthrene, 3,6-dimethylphenanthrene, and 1-, 2-, 3-, and 6-methylchrysene related to their unsubstituted parent PAHs. Also, we observed that body burdens and production of PAAs was related to the position of the methyl group, showing the same isomer specific preferences as for microbial degradation of alkyl-PAHs. We detected a high production of PAAs, and larger metabolism of alkyl-PAHs than their unsubstituted parent PAHs. We therefore propose that carboxylic acid metabolites of alkyl-PAHs have the potential of constituting a new class of contaminants in marine waters that needs attention in relation to ecological risk assessments. PMID:25827176

  4. Polycyclic aromatic acids are primary metabolites of alkyl-PAHs - a case study with Nereis diversicolor

    DEFF Research Database (Denmark)

    Malmquist, Linus Mattias Valdemar; Selck, Henriette; Jørgensen, Kåre Bredeli; Christensen, Jan H.

    2015-01-01

    Although concentrations of alkylated polycyclic aromatic hydrocarbons (alkyl-PAHs) in oil-contaminated sediments are higher than those of unsubstituted PAHs, only little attention has been given to metabolism and ecotoxicity of alkyl-PAHs. In this study we demonstrated that metabolism of alkyl......-PAHs primarily forms polycyclic aromatic acids (PAAs). We generalize this to other alkyl-PAHs, based on literature and the present study of the metabolism of 1-methylphenanthrene, 3,6-dimethylphenanthrene, and 1-, 2-, 3-, and 6-methylchrysene related to their unsubstituted parent PAHs. Also, we observed that...

  5. Physico-chemical properties and toxicity of alkylated polycyclic aromatic hydrocarbons.

    Science.gov (United States)

    Kang, Hyun-Joong; Lee, So-Young; Kwon, Jung-Hwan

    2016-07-15

    Crude oil and refined petroleum products contain many polycyclic and heterocyclic aromatic hydrocarbons, in particular, alkylated PAHs. Although alkylated PAHs are found in significantly higher quantities than their corresponding unsubstituted PAHs, the most studies on the physico-chemical properties and toxicities of these compounds have been conducted on unsubstituted PAHs. In this study, we measured crucial physico-chemical properties (i.e., water solubility, partition coefficients between polydimethylsiloxane and water (KPDMSw), and partition coefficient between liposomes and water (Klipw)) of selected alkylated PAHs, and evaluated their toxicity using the luminescence inhibition of Aliivibrio fischeri and growth inhibition of Raphidocelis subcapitata. In general, the logarithms of these properties for alkylated PAHs showed good linear correlations with log Kow, as did those for unsubstituted PAHs. Changes in molecular symmetry on the introduction of alkyl groups on aromatic ring structure significantly altered water solubility. The inhibition of bacterial luminescence and algal growth by alkylated PAHs can be explained well by the baseline toxicity hypothesis, and good linear relationships between log Kow or log Klipw and log (1/EC50) were found. PMID:27037474

  6. Natural and bioremediated selective degradation of polycyclic aromatic alkyl isomers in oil-contaminated soils

    International Nuclear Information System (INIS)

    In studies where 2- to 6-ring polycyclic aromatic hydrocarbons (PAHs) are determined as part of characterizing released oil constituents in environmental samples, the changes in composition of PAHs from weathering (e.g., evaporation, dissolution) and biodegradation are most often represented by PAH alkyl homologue distributions. Concentrations of PAH alkyl groups are the sum of individual PAH isomers of similar carbon number; such as for C2-naphthalenes, the C2 alkyl group consists of dimethyl and ethyl substitutions on the parent naphthalene. In weathering and degradation studies, the changes in relative concentration of the individual isomers within an alkyl group are rarely reported. In a field study of oiled soils, the authors looked at the selective losses, for a period of a year, of individual PAH alkyl isomers that occur both naturally by weathering processes and through the use of bioremediation technology. Results showed that decreases in alkyl group concentrations were not always represented by similar losses of each isomer in the alkyl group, but were often due to the preferential or selective loss of certain isomers in the group

  7. The use of polynuclear aromatic hydrocarbon (PAH) alkyl homologues in determining petroleum source identification and weathering

    International Nuclear Information System (INIS)

    Techniques utilizing double ratio plots of selected polynuclear aromatic hydrocarbon (PAH) alkyl homologues were used to identify and distinguish crude oils and refined petroleum products from each other and to distinguish petroleum sources in complex pollutant regimes. Petroleum samples were fractionated by high performance liquid chromatography (HPLC) into saturated and aromatic (PAH) hydrocarbon fractions. The saturated hydrocarbon fractions were then analyzed by gas chromatography/flame ionization detection (GC/FID) to obtain a resolved/unresolved alkane fingerprint of each oil. The aromatic fractions of the oils were analyzed by gas chromatography/mass spectrometry (GC/MS) for PAH and selected alkyl homologues. Comparisons of the saturated hydrocarbon fingerprints indicated that some oils were indistinguishable based on the alkane fingerprint alone. Another double ratio plot of the alkyl chrysenes and alkyl dibenzothiophenes was effective in establishing the weathering of oil in environmental samples which were processed using the same analytical techniques, since the dibenzothiophenes are degraded more rapidly than the chrysenes. The application of selected ratios in oil spill source identification in complex environmental samples from Suisin Bay California and Boston Harbor are discussed. The use of ratios to measure the extent of weathering in oil spill samples from Prince William Sound and the Gulf of Alaska is examined

  8. Production of alkyl-aromatics from light oxygenates over zeolite catalysts for bio-oil refining

    Science.gov (United States)

    Hoang, Trung Q.

    in aromatic yield. Further improvement of aromatization and catalyst lifetime was also found with ZnHZSM-5 wherein the Zn evidently modifies the acidity. These model compound results show that the optimized use of zeolites for production of alkyl aromatics from light oxygenates at mild conditions may be effective for bio-oil refining.

  9. Selective side-chain oxidation of alkyl aromatic compounds catalyzed by cerium modified silver catalysts

    DEFF Research Database (Denmark)

    Beier, Matthias Josef; Schimmoeller, Bjoern; Hansen, Thomas Willum; Andersen, Jens Enevold Thaulov; Pratsinis, Sotiris E.; Grunwaldt, Jan-Dierk

    2010-01-01

    Silver supported on silica effectively catalyzes the aerobic side-chain oxidation of alkyl aromatic compounds under solvent-free conditions. Toluene, p-xylene, ethylbenzene and cumene were investigated as model substrates. Typically, the reaction was performed at ambient pressure; only for toluene...... an elevated pressure was required. Carboxylic acids, such as benzoic acid or p-toluic acid, additionally increased the reaction rate while CeO2 could act both as a promoter and an inhibitor depending on the substrate and the reaction conditions. Silver catalysts were prepared both by standard...... catalysis. In addition, flame-made catalysts were more stable against silver leaching compared to the impregnated catalysts. The structure of the silver catalysts was studied in detail both by X-ray absorption spectroscopy and transmission electron microscopy suggesting metallic silver to be required for...

  10. A new spectral deconvolution - selected ion monitoring method for the analysis of alkylated polycyclic aromatic hydrocarbons in complex mixtures.

    Science.gov (United States)

    Robbat, Albert; Wilton, Nicholas M

    2014-07-01

    A new gas chromatography/mass spectrometry (GC/MS) method is proffered for the analysis of polycyclic aromatic hydrocarbons (PAH) and their alkylated homologs in complex samples. Recent work elucidated the fragmentation pathways of alkylated PAH, concluding that multiple fragmentation patterns per homolog (MFPPH) are needed to correctly identify all isomers. Programming the MS in selected ion monitoring (SIM) mode to detect homolog-specific MFPPH ions delivers the selectivity and sensitivity that the conventional SIM and/or full scan mass spectrometry methods fail to provide. New spectral deconvolution software eliminates the practice of assigning alkylated homolog peaks via pattern recognition within laboratory-defined retention windows. Findings show that differences in concentration by SIM/molecular ion detection of C1-C4 PAH, now the standard, yield concentration differences compared to SIM/MFPPH of thousands of percent for some homologs. The SIM/MFPPH methodology is also amenable to the analysis of polycyclic aromatic sulfur heterocycles (PASH) and their alkylated homologs, since many PASH have the same m/z ions as those of PAH and, thus, are false positives in SIM/1-ion PAH detection methods. PMID:24840423

  11. Post-source decay of alkylated and functionalized polycyclic aromatic compounds.

    Science.gov (United States)

    Frache, Gilles; Krier, Gabriel; Vernex-Loset, Lionel; Muller, Jean-François; Manuelli, Pascal

    2007-01-01

    Post-source decay (PSD) is a valuable tool for providing structural information from large molecules by time-of-flight mass spectrometry (TOFMS). We used PSD to obtain this type of data from small molecules in the laser desorption/ionization (LDI) study of diesel engine exhaust particles. As the original nitrogen laser (lambda = 337 nm, E = 3.5 eV/photon) of our TOF mass spectrometer does not yield sufficient energy to ionize polycyclic aromatic hydrocarbons (PAHs), a second laser with a shorter wavelength has been coupled to the instrument. The fourth harmonic of a Nd:YAG laser (lambda = 266 nm, 4.6 eV/photon) has been chosen to achieve two-photon single-step desorption/ionization of PAHs. The PSD fragmentation of functionalized, alkylated and sulfur PAHs is discussed. Diesel engine exhaust particles are also studied as an example of a real complex sample. This technique is presented herein as a way to identify small molecules in environmental samples. Information provided by LDI-PSD-TOFMS can be a way to distinguish pollutants with very close molecular weights even if the resolving power of a TOF mass spectrometer is not sufficient. PMID:17639565

  12. Carbon, hydrogen, and nitrogen isotope fractionation associated with oxidative transformation of substituted aromatic N-alkyl amines.

    Science.gov (United States)

    Skarpeli-Liati, Marita; Pati, Sarah G; Bolotin, Jakov; Eustis, Soren N; Hofstetter, Thomas B

    2012-07-01

    We investigated the mechanisms and isotope effects associated with the N-dealkylation and N-atom oxidation of substituted N-methyl- and N,N-dimethylanilines to identify isotope fractionation trends for the assessment of oxidations of aromatic N-alkyl moieties by compound-specific isotope analysis (CSIA). In laboratory batch model systems, we determined the C, H, and N isotope enrichment factors for the oxidation by MnO(2) and horseradish peroxidase (HRP), derived apparent (13)C-, (2)H-, and (15)N-kinetic isotope effects (AKIEs), and characterized reaction products. The N-atom oxidation pathway leading to radical coupling products typically exhibited inverse (15)N-AKIEs (up to 0.991) and only minor (13)C- and (2)H-AKIEs. Oxidative N-dealkylation, in contrast, was subject to large normal (13)C- and (2)H-AKIEs (up to 1.019 and 3.1, respectively) and small (15)N-AKIEs. Subtle changes of the compound's electronic properties due to different types of aromatic and/or N-alkyl substituents resulted in changes of reaction mechanisms, rate-limiting step(s), and thus isotope fractionation trends. The complex sequence of electron and proton transfers during the oxidative transformation of substituted aromatic N-alkyl amines suggests highly compound- and mechanism-dependent isotope effects precluding extrapolations to other organic micropollutants reacting along the same degradation pathways. PMID:22681573

  13. The development of new materials such MOFs for CO2 capture and alkylation of aromatic compounds

    International Nuclear Information System (INIS)

    This thesis is a European project TOPCOMBI of 22 partners. More specifically, this work is the result of collaboration between ENI (Italy), ITQ (Spain), Repsol (Spain) and IRCELYON (France). This work consists of 2 different themes which improvements can be obtained by finding new materials tailored to the needs. The global energy demands are and will be constantly rising in the coming years. In order to meet this need, new resources must be found and further optimized. Fossil fuels are among the most used resources in the world. Among this 3, natural gas appears to be the most promising point of view of energy efficiency and ecological impact. However, many gas fields cannot be treated because there are too small or too contaminated to be economically viable. One way to make them attractive is to lower the cost of purification using novel separation techniques such as the PSA system. However, there is no currently effective adsorbent to allow a viable economic cleansing. Today, the alkylation reactions represent a very important economic interest. Industrial processes are typically carried out by homogeneous acid reactions or not. Seeing the new environmental restrictions, some homogeneous catalytic processes must be replaced by heterogeneous catalytic reactions with the same yields. To do this, new materials to acid characters were used: the zeolites. However the small size of pores of these compounds prevents selective alkylation reactions of molecules too large compounds such as poly-aromatic. For twenty years, new microporous crystalline compounds have emerged: the MOFs, Metal Organic Frameworks. These compounds have the characteristic to be obtained with different metal cations and organic ligands. These combinations give a wide variety of these compounds at the level of reactivity, pore volume and pore size. In this work, we tried to get different materials with specific characteristics in order to use them in methods for purification of methane in acid

  14. Unresolved complex mixtures (UCMs) of aromatic hydrocarbons: branched alkyl indanes and branched alkyl tetralins are present in UCMs and accumulated by and toxic to, the mussel Mytilus edulis.

    Science.gov (United States)

    Booth, Andrew M; Scarlett, Alan G; Lewis, C Anthony; Belt, Simon T; Rowland, Steven J

    2008-11-01

    Previously, comprehensive two-dimensional gas chromatography-time of flight-mass-spectrometry (GCxGC-ToF-MS) revealed that the unresolved complex mixtures (UCMs) of contaminant hydrocarbons accumulated by health-affected mussels Mytilus edulis (up to 125 microg g dry weight(-1)) collected from around U.K. coasts, included many isomeric branched alkyl benzenes (BABs). A commercial mixture of BABs (C12-C14) was toxic to mussels in laboratorytests (tissue effective concentration EC(20)10.5 microg g dry tissue(-1)). Branched alkyl indanes (BINs) and branched alkyl tetralins (BATs) were also tentatively identified in the wild mussels, but no commercial sources of BINs or BATs were available for compound confirmation or toxicity testing. In the present study, we synthesized 14 isomeric BINs and BATs, investigated their chromatographic and mass spectral properties and measured their toxicity to mussels (Mytilus edulis). Comparison of the results of GCxGC-ToF-MS analysis of the synthesized compounds with those of complex mixtures of BINs and BATs in wild mussels confirmed the previous tentative identifications. Toxicity assays showed that in 72 h exposures, each of the synthetic BINs and BATs and a mixture of all were toxic to mussels at concentrations comparable to the BABs investigated previously (EC(20)13 microg g dry tissue(-1)). A further 5 day recovery period in clean water resulted in incomplete depuration of the accumulated body burden of BINs and BATs by the mussels. We suggest that monitoring of hydrocarbon contaminants in mussels should include an assessment of the concentrations of aromatic UCMs and ideally identification and measurement of the concentrations of BABs, BINs, and BATs and other toxic UCM components in order that the effects of these toxicants are not overlooked. PMID:19031912

  15. 40 CFR 721.7200 - Perfluoroalkyl aromatic carbamate modified alkyl methacrylate copolymer.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Perfluoroalkyl aromatic carbamate... Significant New Uses for Specific Chemical Substances § 721.7200 Perfluoroalkyl aromatic carbamate modified...) The chemical substance identified generically as perfluoroalkyl aromatic carbamate modified...

  16. Camphor-10-sulfonic acid catalyzed condensation of 2-naphthol with aromatic/aliphatic aldehydes to 14-aryl/alkyl-14H-dibenzo[a,j]xanthenes

    Directory of Open Access Journals (Sweden)

    Kundu Kshama

    2014-01-01

    Full Text Available (±-Camphor-10-sulfonic acid (CSA catalyzed condensation of 2-naphthol with both aliphatic/aromatic aldehydes at 80°C yielded 14-alkyl/aryl-dibenzoxanthenes as the sole product in high yields. However, the same condensation with benzaldehyde at 25°C afforded a mixture of intermediate 1,1-bis-(2-hydroxynaphthylphenylmethane and 14-phenyl-dibenzoxanthene while the condensation with aliphatic aldehydes at 25°C furnished the corresponding 14-alkyl-dibenzoxanthenes as the sole product. Moreover, condensation of 2-naphthol with aromatic/aliphatic aldehydes with low catalyst loading (2 mol% was greatly accelerated under microwave irradiation to afford the corresponding 14-aryl/alkyl-dibenzoxanthenes as the sole product in high yields.

  17. Polycyclic aromatic hydrocarbons (PAHs) and alkylated PAHs in the coastal seawater, surface sediment and oyster from Dalian, Northeast China.

    Science.gov (United States)

    Hong, Wen-Jun; Jia, Hongliang; Li, Yi-Fan; Sun, Yeqing; Liu, Xianjie; Wang, Luo

    2016-06-01

    A total of 46 polycyclic aromatic hydrocarbons (PAHs, 21 parent and 25 alkylated) were determined in seawater, surface sediment and oyster from coastal area of Dalian, North China. The concentration of Σ46PAHs in seawater, sediment, and oyster were 136-621ng/L, 172-4700ng/g dry weight (dw) and 60.0-129 ng/g wet weight (ww) in winter, and 65.0-1130ng/L, 71.1-1090ng/g dw and 72.8-216ng/g ww in summer, respectively. High PAH levels were found in industrial area both in winter and summer. Selected PAH levels in sediments were compared with Sediments Quality Guidelines (ERM-ERL, TEL-PEL indexes) for evaluation probable toxic effects on marine organism and the results indicate that surface sediment from all sampling sites have a low to medium ecotoxicological risk. Daily intake of PAHs via oyster as seafood by humans were estimated and the results indicated that oyster intake would not pose a health risk to humans even 30 days after a oil spill accident near by. Water-sediment exchange analysis showed that, both in winter and summer, the fluxes for most high molecular weight PAHs were from seawater to sediment, while for low molecular weight PAHs, an equilibrium was reached between seawater and sediment. PMID:26874984

  18. Retention behavior of alkylated polycyclic aromatic sulfur heterocycles on immobilized ionic liquid stationary phases.

    Science.gov (United States)

    Antle, Patrick; Zeigler, Christian; Robbat, Albert

    2014-09-26

    Polycyclic aromatic sulfur heterocycles (PASH) are prevalent components of fossil fuel-based pollutants, and their accurate analysis is of critical importance in risk assessment and hazardous waste site remediation. PASH, however, have a wide range of volatilities and polarities and, as such, often coelute with one another and other sample components on the non-polar gas chromatography (GC) columns commonly used in their analysis. Immobilized ionic liquid (IL)-based stationary phases have been shown to provide better separation of polar compounds than non-polar columns, while withstanding higher temperatures than typical polar columns. In this way, they offer the opportunity of improved performance in the analysis of PASH in complex environmental samples and as the "more polar" column in GC×GC/MS analyses. In this study, the retention behavior of 119 PASH on four commercially-available IL stationary phases is reported and compared to behavior on three polydimethylsiloxane-based columns of varying polarities (DB-5, DB-17, and DB-200). Additionally, the utility of IL columns in GC×GC analyses of PASH-containing coal tar samples is examined. PMID:25155062

  19. Characterizing the parent and alkyl polycyclic aromatic hydrocarbons in the Pearl River Estuary, Daya Bay and northern South China Sea: Influence of riverine input

    International Nuclear Information System (INIS)

    Distributions of 31 parent polycyclic aromatic hydrocarbons (PAHs) and 29 alkyl PAHs in surface sediments of the Pearl River Estuary (PRE), Daya Bay (DYB) and northern South China Sea (SCS) were examined to study the influence of riverine input. It was found that the contributions of riverine input to sediment PAHs in PRE was much higher than other areas. However, higher proportion of alkyl PAHs and low molecular weight PAHs in DYB and the northern SCS was observed, indicating their different sources. Nevertheless, the sediment PAHs in PRE were heterogeneous and affected by the hydrodynamic conditions. The high molecular weight PAHs were dominant in PRE and enriched in the depositional area of suspended particular matter (SPM). Moreover, the concentration of PAHs in SPM was similar to those in surface sediments and dominated in water columns. Therefore, SPM played a very important role in transportation and distribution of PAHs in PRE. - Highlights: • EPA 16 PAHs contributed a small amount of total PAHs. • Alkyl PAHs showed different behaviors from parent PAHs. • High weight PAHs preferably indicated riverine input. • PAHs distribution in sediment was related with the suspended particle deposition. - Suspended particular matter played a very important role in distribution of PAHs in tide-dominated estuary and alkyl PAHs showed different behavior from parent PAHs

  20. Rate and pathways for the reaction of OH with the biogenic p-cymene, an alkylated aromatic

    Science.gov (United States)

    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

  1. Genomic Phenotyping by Barcode Sequencing Broadly Distinguishes between Alkylating Agents, Oxidizing Agents, and Non-Genotoxic Agents, and Reveals a Role for Aromatic Amino Acids in Cellular Recovery after Quinone Exposure

    Science.gov (United States)

    Svensson, J. Peter; Quirós Pesudo, Laia; McRee, Siobhan K.; Adeleye, Yeyejide; Carmichael, Paul; Samson, Leona D.

    2013-01-01

    Toxicity screening of compounds provides a means to identify compounds harmful for human health and the environment. Here, we further develop the technique of genomic phenotyping to improve throughput while maintaining specificity. We exposed cells to eight different compounds that rely on different modes of action: four genotoxic alkylating (methyl methanesulfonate (MMS), N-Methyl-N-nitrosourea (MNU), N,N′-bis(2-chloroethyl)-N-nitroso-urea (BCNU), N-ethylnitrosourea (ENU)), two oxidizing (2-methylnaphthalene-1,4-dione (menadione, MEN), benzene-1,4-diol (hydroquinone, HYQ)), and two non-genotoxic (methyl carbamate (MC) and dimethyl sulfoxide (DMSO)) compounds. A library of S. cerevisiae 4,852 deletion strains, each identifiable by a unique genetic ‘barcode’, were grown in competition; at different time points the ratio between the strains was assessed by quantitative high throughput ‘barcode’ sequencing. The method was validated by comparison to previous genomic phenotyping studies and 90% of the strains identified as MMS-sensitive here were also identified as MMS-sensitive in a much lower throughput solid agar screen. The data provide profiles of proteins and pathways needed for recovery after both genotoxic and non-genotoxic compounds. In addition, a novel role for aromatic amino acids in the recovery after treatment with oxidizing agents was suggested. The role of aromatic acids was further validated; the quinone subgroup of oxidizing agents were extremely toxic in cells where tryptophan biosynthesis was compromised. PMID:24040048

  2. Liquid-phase alkylation of Assam (Baragolai) coal

    Energy Technology Data Exchange (ETDEWEB)

    Kalra, R.L.; Choudhury, R.; Sarkar, M.K.

    1982-12-01

    Liquid paraffin which consists of a large number of alkylated aliphatics and aromatics seems to be acting as an alkyl group transfer medium to receptive complexes like coal. The alkyl group receptive spots could be created in the coal complex by treatment with molten alkalis like sodium or potassium hydroxide. By repeating extractions of fresh coal with the same volume of liquid paraffin on a laboratory scale it was found that a stage was reached when liquid paraffin became rich enough in alkyl groups to become an alkyl group donor. This suggests a method for liquid phase alkylation of coal. (3 refs.)

  3. New and extended parameterization of the thermodynamic model AIOMFAC: calculation of activity coefficients for organic-inorganic mixtures containing carboxyl, hydroxyl, carbonyl, ether, ester, alkenyl, alkyl, and aromatic functional groups

    Directory of Open Access Journals (Sweden)

    A. Zuend

    2011-09-01

    Full Text Available We present a new and considerably extended parameterization of the thermodynamic activity coefficient model AIOMFAC (Aerosol Inorganic-Organic Mixtures Functional groups Activity Coefficients at room temperature. AIOMFAC combines a Pitzer-like electrolyte solution model with a UNIFAC-based group-contribution approach and explicitly accounts for interactions between organic functional groups and inorganic ions. Such interactions constitute the salt-effect, may cause liquid-liquid phase separation, and affect the gas-particle partitioning of aerosols. The previous AIOMFAC version was parameterized for alkyl and hydroxyl functional groups of alcohols and polyols. With the goal to describe a wide variety of organic compounds found in atmospheric aerosols, we extend here the parameterization of AIOMFAC to include the functional groups carboxyl, hydroxyl, ketone, aldehyde, ether, ester, alkenyl, alkyl, aromatic carbon-alcohol, and aromatic hydrocarbon. Thermodynamic equilibrium data of organic-inorganic systems from the literature are critically assessed and complemented with new measurements to establish a comprehensive database. The database is used to determine simultaneously the AIOMFAC parameters describing interactions of organic functional groups with the ions H+, Li+, Na+, K+, NH4+, Mg2+, Ca2+, Cl, Br, NO3, HSO4, and SO42−. Detailed descriptions of different types of thermodynamic data, such as vapor-liquid, solid-liquid, and liquid-liquid equilibria, and their use for the model parameterization are provided. Issues regarding deficiencies of the database, types and uncertainties of experimental data, and limitations of the model, are discussed. The challenging parameter optimization problem is solved with a novel combination of powerful global minimization

  4. New and extended parameterization of the thermodynamic model AIOMFAC: calculation of activity coefficients for organic-inorganic mixtures containing carboxyl, hydroxyl, carbonyl, ether, ester, alkenyl, alkyl, and aromatic functional groups

    Directory of Open Access Journals (Sweden)

    A. Zuend

    2011-05-01

    Full Text Available We present a new and considerably extended parameterization of the thermodynamic activity coefficient model AIOMFAC (Aerosol Inorganic-Organic Mixtures Functional groups Activity Coefficients at room temperature. AIOMFAC combines a Pitzer-like electrolyte solution model with a UNIFAC-based group-contribution approach and explicitly accounts for interactions between organic functional groups and inorganic ions. Such interactions constitute the salt-effect, may cause liquid-liquid phase separation, and affect the gas-particle partitioning of aerosols. The previous AIOMFAC version was parameterized for alkyl and hydroxyl functional groups of alcohols and polyols. With the goal to describe a wide variety of organic compounds found in atmospheric aerosols, we extend here the parameterization of AIOMFAC to include the functional groups carboxyl, hydroxyl, ketone, aldehyde, ether, ester, alkenyl, alkyl, aromatic carbon-alcohol, and aromatic hydrocarbon. Thermodynamic equilibrium data of organic-inorganic systems from the literature are critically assessed and complemented with new measurements to establish a comprehensive database. The database is used to determine simultaneously the AIOMFAC parameters describing interactions of organic functional groups with the ions H+, Li+, Na+, K+, NH4+, Mg2+, Ca2+, Cl, Br, NO3, HSO4, and SO42−. Detailed descriptions of different types of thermodynamic data, such as vapor-liquid, solid-liquid, and liquid-liquid equilibria, and their use for the model parameterization are provided. Issues regarding deficiencies of the database, types and uncertainties of experimental data, and limitations of the model, are discussed. The challenging parameter optimization problem is solved with a novel combination of powerful global minimization

  5. Alkyl glycosides

    Czech Academy of Sciences Publication Activity Database

    Wimmer, Zdeněk; Zarevúcka, Marie; Šaman, David

    Venice, 2004. s. 20-21. [Sustainable Green Chemistry and Chemical Technology. Workshop /3./. 20.02.2004-21.02.2004, Venice] R&D Projects: GA ČR GA203/02/0166; GA MŠk OC D29.001 Keywords : alkyl glycosides Subject RIV: CC - Organic Chemistry

  6. Lithium Alkyl Exchange Equilibria

    International Nuclear Information System (INIS)

    Kinetic analyses of two types of exchange reactions of organo- lithium reagents, both alkyl and aryl types, RLi, have been made: (1) halogen-metal interchange with alkyl and aryl halides, R'X, and (2) hydrogen-metal interchange (commonly called metallation) with aromatic hydrocarbons, R'H. Rates of these RLi + R'X ⇄ RX + R'Li; (1) . RLi + R'H ⇄ RH+ R'Li (2) reactions have been determined, conditions under which the systems attain equilibrium have been established, and the positions of equilibrium measured, all as functions of the reactants, solvents and catalysts employed. Concerning halogen-lithium interchange between alkyl groups (1), the conclusion is reached that equilibration proceeds to yield the less sterically demanding alkyl group attached to lithium. The data show, for example, that isobutyllithium is much less stable than n-butyllithium, and again, that 2,6-dimethyl- phenyllithium is much less stable than phenyllithium. The exchange is general with iodides, occurs with some bromides and does not occur with chlorides. The exchange is quite slow in hydrocarbon media and is catalysed by relatively small amounts of ethers. In the presence of the optically active methyl ether of menthol, methyl iodide exchanges with racemic s-butyllithium to give optically active s-butyl iodide. In work with the second reaction, hydrogen-lithium interchange (2), nuclear magnetic resonance spectrometry has been used for rate studies. Catalysts (Lewis bases) have been evolved for establishing equilibria in rather unreactive systems, e.g. phenyllithium can be demonstrated to exchange with benzene by labelling the latter radioactivity. From the correlations of structure and reactivity found in this study, the conclusion is reached that the basic alkyllithium structure is dimeric, R2Li2 The arrangement of the groups within this dimer satisfactorily explain the special steric effects noted in organolithium reagent stability. (author)

  7. Bacterial Degradation of Aromatic Compounds

    Directory of Open Access Journals (Sweden)

    Qing X. Li

    2009-01-01

    Full Text Available 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.

  8. Distance-Dependent Attractive and Repulsive Interactions of Bulky Alkyl Groups.

    Science.gov (United States)

    Hwang, Jungwun; Li, Ping; Smith, Mark D; Shimizu, Ken D

    2016-07-01

    The stabilizing and destabilizing effects of alkyl groups on an aromatic stacking interaction were experimentally measured in solution. The size (Me, Et, iPr, and tBu) and position (meta and para) of the alkyl groups were varied in a molecular balance model system designed to measure the strength of an intramolecular aromatic interaction. Opposite stability trends were observed for alkyl substituents at different positions on the aromatic rings. At the closer meta-position, smaller groups were stabilizing and larger groups were destabilizing. Conversely, at the farther para-position, the larger alkyl groups were systematically more stabilizing with the bulky tBu group forming the strongest stabilizing interaction. X-ray crystal structures showed that the stabilizing interactions of the small meta-alkyl and large para-alkyl groups were due to their similar distances and van der Waals contact areas with the edge of opposing aromatic ring. PMID:27159670

  9. Aromatic oligoamides with a rare ortho-connectivity

    DEFF Research Database (Denmark)

    Hjelmgaard, T.; Nielsen, John

    2013-01-01

    Even though aromatic oligoamides composed of aromatic amino acids in a "one-way sequence" attract ever increasing research interest, backbones connected through ortho-linked aromatics remain rare. Herein, we present the first synthesis and study of N-alkylated ortho-aminomethyl- benzamides termed...

  10. Alkyl aryl ethers in lignite solubilization

    Energy Technology Data Exchange (ETDEWEB)

    Mustral, A.M.; Cebolla, V.L.; Gavilan, J.M.

    1985-03-01

    The FT-I.R. and /sup 1/H N.M.R. spectroscopic analyses of oils or maltenes from a Spanish lignite (Utrillas, Teruel), are reported. These oils were obtained by depolymerization with alkyl aromatic ethers (anisole, 3-methyl anisole and 1,3-dimethoxybenzene) catalyzed by Lewis acids ZnCl/sub 2/, AlCl/sub 3/, SbCl/sub 3/ and BF/sub 3/ (as boron trifluoride etherate), at atmospheric pressure and temperatures <220/sup 0/C. Bands due to aromatic ethers in the I.R. and N.M.R. spectra of the oils obtained by depolymerization indicate solvent incorporation. Oils obtained by direct lignite extraction showed 25% aromatic H and some H /sub i/ (approx. = 3%) without OH groups. These appeared in some oils obtained by depolymerization with AlCl/sub 3/ and were due to secondary reactions with the aromatic extract. Oils derived from processes with good yields showed increases in aromaticity. The extent of substitution of aromatic rings in oils obtained by depolymerization was less than for oils directly extracted. All the oils studied show a low degree of condensation.

  11. Aromaticity influencing the thermostability of micellar dispersions

    Energy Technology Data Exchange (ETDEWEB)

    Davis, J.A.; Kunzman, W.J.

    1970-02-17

    The thermostability of a micellar dispersion is shifted to higher temperature ranges by increasing the aromaticity of the hydrocarbon within the dispersion. The micellar solution is composed of kerosene and light catalytic cycle oil (hydrocarbons), water, sodium or ammonium alkyl aryl naphthenic sulfonates (petroleum sulfonate surfactant), isopropanol (cosurfactant), and sodium sulfate (electrolyte). The aromatic content of the light catalytic cycle oil is higher than the aromatic content of the kerosene. By increasing the concentration of cycle oil to kerosene, stable micellar solutions at temperatures from ambient to 200/sup 0/F can be obtained. The aqueous medium can be soft, brackish, or a brine.

  12. Potential Metabolic Activation of a Representative C2-Alkylated Polycyclic Aromatic Hydrocarbon 6-Ethylchrysene Associated with the Deepwater Horizon Oil Spill in Human Hepatoma (HepG2) Cells

    Science.gov (United States)

    2016-01-01

    Exposure to polycyclic aromatic hydrocarbons (PAHs) is the major human health hazard associated with the Deepwater Horizon oil spill. C2-Chrysenes are representative PAHs present in crude oil and could contaminate the food chain. We describe the metabolism of a C2-chrysene regioisomer, 6-ethylchrysene (6-EC), in human HepG2 cells. The structures of the metabolites were identified by HPLC-UV-fluorescence detection and LC-MS/MS. 6-EC-tetraol isomers were identified as signature metabolites of the diol-epoxide pathway. O-Monomethyl-O-monosulfonated-6-EC-catechol, its monohydroxy products, and N-acetyl-l-cysteine(NAC)-6-EC-ortho-quinone were discovered as signature metabolites of the ortho-quinone pathway. Potential dual metabolic activation of 6-EC involving the formation of bis-electrophiles, i.e., a mono-diol-epoxide and a mono-ortho-quinone within the same structure, bis-diol-epoxides, and bis-ortho-quinones was observed as well. The identification of 6-EC-tetraol, O-monomethyl-O-monosulfonated-6-EC-catechol, its monohydroxy products, and NAC-6-EC-ortho-quinone supports potential metabolic activation of 6-EC by P450 and AKR enzymes followed by metabolic detoxification of the ortho-quinone through interception of its redox cycling capability by catechol-O-methyltransferase and sulfotransferase enzymes. The tetraols and catechol conjugates could be used as biomarkers of human exposure to 6-EC resulting from oil spills. PMID:27054409

  13. Potential Metabolic Activation of a Representative C2-Alkylated Polycyclic Aromatic Hydrocarbon 6-Ethylchrysene Associated with the Deepwater Horizon Oil Spill in Human Hepatoma (HepG2) Cells.

    Science.gov (United States)

    Huang, Meng; Mesaros, Clementina; Zhang, Suhong; Blair, Ian A; Penning, Trevor M

    2016-06-20

    Exposure to polycyclic aromatic hydrocarbons (PAHs) is the major human health hazard associated with the Deepwater Horizon oil spill. C2-Chrysenes are representative PAHs present in crude oil and could contaminate the food chain. We describe the metabolism of a C2-chrysene regioisomer, 6-ethylchrysene (6-EC), in human HepG2 cells. The structures of the metabolites were identified by HPLC-UV-fluorescence detection and LC-MS/MS. 6-EC-tetraol isomers were identified as signature metabolites of the diol-epoxide pathway. O-Monomethyl-O-monosulfonated-6-EC-catechol, its monohydroxy products, and N-acetyl-l-cysteine(NAC)-6-EC-ortho-quinone were discovered as signature metabolites of the ortho-quinone pathway. Potential dual metabolic activation of 6-EC involving the formation of bis-electrophiles, i.e., a mono-diol-epoxide and a mono-ortho-quinone within the same structure, bis-diol-epoxides, and bis-ortho-quinones was observed as well. The identification of 6-EC-tetraol, O-monomethyl-O-monosulfonated-6-EC-catechol, its monohydroxy products, and NAC-6-EC-ortho-quinone supports potential metabolic activation of 6-EC by P450 and AKR enzymes followed by metabolic detoxification of the ortho-quinone through interception of its redox cycling capability by catechol-O-methyltransferase and sulfotransferase enzymes. The tetraols and catechol conjugates could be used as biomarkers of human exposure to 6-EC resulting from oil spills. PMID:27054409

  14. Identify alkylation hazards

    International Nuclear Information System (INIS)

    This paper reports that extensive experience shows that alkylation plants regardless of acid catalyst choice, can be operated safely, and with minimum process risk to employees or neighbors. Both types of plants require a comprehensive and fully supported hazard management program that accounts for differing physical properties of the acids involved. Control and mitigation cost to refiners will vary considerably from plant to plant and location to location. In the author's experience, the order of magnitude costs will be about $1 to $2 million for a sulfuric acid (SA) alkylation plant, and about $10 to $15 million for a hydrofluoric acid (HF) plant. These costs include water supply systems and impoundment facilities for contaminated runoff water. The alkylation process, which chemically reacts isobutane and light olefins in the presence of a strong acid catalyst into a premium gasoline component is described

  15. Quantitative structure–activity relationships for chronic toxicity of alkyl-chrysenes and alkyl-benz[a]anthracenes to Japanese medaka embryos (Oryzias latipes)

    International Nuclear Information System (INIS)

    Highlights: • Medaka embryos were exposed to alkyl chrysenes and benzo[a]anthracenes (BAA). • Concentrations were kept constant by partition controlled delivery. • Chrysene was not toxic within solubility limits, in contrast to BAA. • Alkylation increased the toxicity of chrysene and BAA. • Toxicity was related to hydrophobicity and to specific modes of action. - Abstract: Alkylated polycyclic aromatic hydrocarbons (alkyl-PAHs) are a class of compounds found at significant concentrations in crude oils, and likely the main constituents responsible for the chronic toxicity of oil to fish. Alkyl substituents at different locations on the aromatic rings change the size and shape of PAH molecules, which results in different interactions with tissue receptors and different severities of toxicity. The present study is the first to report the toxicity of several alkylated derivatives of chrysene and benz[a]anthracene to the embryos of Japanese medaka (Oryzias latipes) using the partition controlled delivery (PCD) method of exposure. The PCD method maintained the desired exposure concentrations by equilibrium partitioning of hydrophobic test compounds from polydimethylsiloxane (PDMS) films. Test concentrations declined by only 13% over a period of 17 days. Based on the prevalence of signs of blue sac disease (BSD), as expressed by median effective concentrations (EC50s), benz[a]anthracene (B[a]A) was more toxic than chrysene. Alkylation generally increased toxicity, except at position 2 of B[a]A. Alkyl-PAHs substituted in the middle region had a lower EC50 than those substituted at the distal region. Except for B[a]A and 7-methylbenz[a]anthracene (7-MB), estimated EC50 values were higher than their solubility limits, which resulted in limited toxicity within the range of test concentrations. The regression between log EC50s and log Kow values provided a rough estimation of structure–activity relationships for alkyl-PAHs, but Kow alone did not provide a complete

  16. Novel Approach for Evaluating Secondary Organic Aerosol from Aromatic Hydrocarbons: SOA Yield and Chemical Composition

    Science.gov (United States)

    Li, Lijie; Tang, Ping; Nakao, Shunsuke; Qi, Li; Kacarab, Mary; Cocker, David

    2016-04-01

    Aromatic hydrocarbons account for 20%-30% of urban atmospheric VOCs and are major contributors to anthropogenic secondary organic aerosol (SOA). However, prediction of SOA from aromatic hydrocarbons as a function of structure, NOx concentration, and OH radical levels remains elusive. Innovative SOA yield and chemical composition evaluation approaches are developed here to investigate SOA formation from aromatic hydrocarbons. SOA yield is redefined in this work by adjusting the molecular weight of all aromatic precursors to the molecular weight of benzene (Yield'= Yieldi×(MWi/MWBenzene); i: aromatic hydrocarbon precursor). Further, SOA elemental ratio is calculated on an aromatic ring basis rather than the classic mole basis. Unified and unique characteristics in SOA formed from aromatic hydrocarbons with different alkyl groups (varying in carbon number and location on aromatic ring) are explored by revisiting fifteen years of UC Riverside/CE-CERT environmental chamber data on 129 experiments from 17 aromatic precursors at urban region relevant low NOx conditions (HC:NO 11.1-171 ppbC:ppb). Traditionally, SOA mass yield of benzene is much greater than that of other aromatic species. However, when adjusting for molecular weight, a similar yield is found across the 17 different aromatic precursors. More importantly, four oxygens per aromatic ring are observed in the resulting SOA regardless of the alkyl substitutes attached to the ring, which majorly affect H/C ratio in SOA. Therefore, resulting SOA bulk composition from aromatic hydrocarbons can be predicted as C6+nH6+2nO4 (n: alkyl substitute carbon number). Further, the dominating role of the aromatic ring carbons is confirmed by studying the chemical composition of SOA formed from the photooxidation of an aromatic hydrocarbon with a 13C isotopically labeled alkyl carbon. Overall, this study unveils the similarity in SOA formation from aromatic hydrocarbons enhancing the understanding of SOA formation from

  17. Method of making alkyl esters

    Science.gov (United States)

    Elliott, Brian

    2010-09-14

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

  18. Transformations of aromatic hydrocarbons over zeolites

    Czech Academy of Sciences Publication Activity Database

    Voláková, Martina; Žilková, Naděžda; Čejka, Jiří

    2008-01-01

    Roč. 34, 5-7 (2008), s. 439-454. ISSN 0922-6168 R&D Projects: GA ČR GA203/05/0197; GA AV ČR 1QS400400560; GA AV ČR KJB4040402 Institutional research plan: CEZ:AV0Z40400503 Keywords : aromatic hydrocarbons * zeolites * alkylation Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 0.514, year: 2008

  19. 40 CFR 721.9595 - Alkyl benzene sulfonic acids and alkyl sulfates, amine salts (generic).

    Science.gov (United States)

    2010-07-01

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

  20. Samarium-promoted Chemoselective Reduction of Aromatic Nitro Compounds in Ionic Liquid

    Institute of Scientific and Technical Information of China (English)

    ZHENG,Xing-Liang(郑兴良); ZHANG,Yong-Min(张永敏)

    2002-01-01

    The differently substituted aromatic nitro compoumds were chemoselectively reduced by Sm/HOAc system in an ionic liquid medium to afford aromatic amines. Under these conditions the other substituents, such as -X, -CHO, -COOH, -CN,-NHTos and - alkyl, remained intact. The notable advantagesofthis reaction areits mild conditions, simple operaton,short reaction time, high yields and easy recycling of ionic liquid.

  1. Aromatic graphene

    Science.gov (United States)

    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.

  2. Perfluorinated Alkyl Substances

    DEFF Research Database (Denmark)

    Grandjean, Philippe; Clapp, Richard

    2015-01-01

    Perfluorinated alkyl substances have been in use for over sixty years. These highly stable substances were at first thought to be virtually inert and of low toxicity. Toxicity information slowly emerged on perfluorooctanoic acid and perfluorooctane sulfonate. More than thirty years ago, early...... studies reported immunotoxicity and carcinogenicity effects. The substances were discovered in blood samples from exposed workers, then in the general population and in community water supplies near U.S. manufacturing plants. Only recently has research publication on perfluorooctanoic acid and...... perfluorooctane sulfonate intensified. While the toxicology database is still far from complete, carcinogenicity and immunotoxicity now appear to be relevant risks at prevalent exposure levels. Existing drinking water limits are based on less complete evidence that was available before 2008 and may be more than...

  3. Quantitative structure–activity relationships for chronic toxicity of alkyl-chrysenes and alkyl-benz[a]anthracenes to Japanese medaka embryos (Oryzias latipes)

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Hongkang [Department of Biology, Queen' s University, Kingston, Ontario K7L3N6 (Canada); Morandi, Garrett D. [School of Environmental Studies, Queen' s University, Kingston, Ontario K7L3N6 (Canada); Brown, R. Stephen [School of Environmental Studies, Queen' s University, Kingston, Ontario K7L3N6 (Canada); Department of Chemistry, Queen' s University, Kingston, Ontario K7L3N6 (Canada); Snieckus, Victor; Rantanen, Toni [Department of Chemistry, Queen' s University, Kingston, Ontario K7L3N6 (Canada); Jørgensen, Kåre B. [Department of Mathematics and Natural Sciences, University of Stavanger, 4036 Stavanger (Norway); Hodson, Peter V., E-mail: peter.hodson@queensu.ca [Department of Biology, Queen' s University, Kingston, Ontario K7L3N6 (Canada); School of Environmental Studies, Queen' s University, Kingston, Ontario K7L3N6 (Canada)

    2015-02-15

    Highlights: • Medaka embryos were exposed to alkyl chrysenes and benzo[a]anthracenes (BAA). • Concentrations were kept constant by partition controlled delivery. • Chrysene was not toxic within solubility limits, in contrast to BAA. • Alkylation increased the toxicity of chrysene and BAA. • Toxicity was related to hydrophobicity and to specific modes of action. - Abstract: Alkylated polycyclic aromatic hydrocarbons (alkyl-PAHs) are a class of compounds found at significant concentrations in crude oils, and likely the main constituents responsible for the chronic toxicity of oil to fish. Alkyl substituents at different locations on the aromatic rings change the size and shape of PAH molecules, which results in different interactions with tissue receptors and different severities of toxicity. The present study is the first to report the toxicity of several alkylated derivatives of chrysene and benz[a]anthracene to the embryos of Japanese medaka (Oryzias latipes) using the partition controlled delivery (PCD) method of exposure. The PCD method maintained the desired exposure concentrations by equilibrium partitioning of hydrophobic test compounds from polydimethylsiloxane (PDMS) films. Test concentrations declined by only 13% over a period of 17 days. Based on the prevalence of signs of blue sac disease (BSD), as expressed by median effective concentrations (EC50s), benz[a]anthracene (B[a]A) was more toxic than chrysene. Alkylation generally increased toxicity, except at position 2 of B[a]A. Alkyl-PAHs substituted in the middle region had a lower EC50 than those substituted at the distal region. Except for B[a]A and 7-methylbenz[a]anthracene (7-MB), estimated EC50 values were higher than their solubility limits, which resulted in limited toxicity within the range of test concentrations. The regression between log EC50s and log K{sub ow} values provided a rough estimation of structure–activity relationships for alkyl-PAHs, but K{sub ow} alone did not provide

  4. Mild Catalytic methods for Alkyl-Alkyl Bond Formation

    Energy Technology Data Exchange (ETDEWEB)

    Vicic, David A

    2009-08-10

    Overview of Research Goals and Accomplishments for the Period 07/01/06 – 06/30/07: Our overall research goal is to transform the rapidly emerging synthetic chemistry involving alkyl-alkyl cross-couplings into more of a mechanism-based field so that that new, rationally-designed catalysts can be performed under energy efficient conditions. Our specific objectives for the previous year were 1) to obtain a proper electronic description of an active catalyst for alkyl-alkyl cross-coupling reactions and 2) to determine the effect of ligand structure on the rate, scope, selectivity, and functional group compatibility of C(sp3)-C(sp3) cross-coupling catalysis. We have completed both of these initial objectives and established a firm base for further studies. The specific significant achievements of the current grant period include: 1) we have performed magnetic and computational studies on (terpyridine)NiMe, an active catalyst for alkyl-alkyl cross couplings, and have discovered that the unpaired electron resides heavily on the terpyridine ligand and that the proper electronic description of this nickel complex is a Ni(II)-methyl cation bound to a reduced terpyridine ligand; 2) we have for the first time shown that alkyl halide reduction by terpyridyl nickel catalysts is substantially ligand based; 3) we have shown by isotopic labeling studies that the active catalyst (terpyridine)NiMe is not produced via a mechanism that involves the formation of methyl radicals when (TMEDA)NiMe2 is used as the catalyst precursor; 4) we have performed an extensive ligand survey for the alkyl-alkyl cross-coupling reactions and have found that electronic factors only moderately influence reactivity in the terpyridine-based catalysis and that the most dramatic effects arise from steric and solubility factors; 5) we have found that the use of bis(dialkylphosphino)methanes as ligands for nickel does not produce active catalysts for cross-coupling but rather leads to bridging hydride

  5. From lignin to cycloparaffins and aromatics: directional synthesis of jet and diesel fuel range biofuels using biomass.

    Science.gov (United States)

    Bi, Peiyan; Wang, Jicong; Zhang, Yajing; Jiang, Peiwen; Wu, Xiaoping; Liu, Junxu; Xue, He; Wang, Tiejun; Li, Quanxin

    2015-05-01

    The continual growth in commercial aviation fuels and more strict environmental legislations have led to immense interest in developing green aviation fuels from biomass. This paper demonstrated a controllable transformation of lignin into jet and diesel fuel range hydrocarbons, involving directional production of C8-C15 aromatics by the catalytic depolymerization of lignin into C6-C8 low carbon aromatic monomers coupled with the alkylation of aromatics, and the directional production of C8-C15 cycloparaffins by the hydrogenation of aromatics. The key step, the production of the desired C8-C15 aromatics with the selectivity up to 94.3%, was achieved by the low temperature alkylation reactions of the lignin-derived monomers using ionic liquid. The synthetic biofuels basically met the main technical requirements of conventional jet fuels. The transformation potentially provides a useful way for the development of cycloparaffinic and aromatic components in jet fuels using renewable lignocellulose biomass. PMID:25710678

  6. A biological source of oceanic alkyl nitrates

    Science.gov (United States)

    Dahl, E. E.; Lewis, C. B.; Velasco, F. L.; Escobar, C.; Kellogg, D.; Velcamp, M.

    2013-12-01

    Alkyl nitrates are an important component of reactive nitrogen in the troposphere. The oceans are a source of alkyl nitrates to the atmosphere, however the source of alkyl nitrates in the oceans is unknown. It has been demonstrated that the reaction of alkyl peroxy radicals (ROO) with nitric oxide (NO) produces alkyl nitrates in the aqueous phase. We hypothesize that alkyl nitrates may be formed by organisms through the same reaction and therefore biological production could be a source of alkyl nitrates to the troposphere. This work focuses on the production of alkyl nitrates by the diatoms Chaetoceros muelleri and Thalassiosira weisfloggi. Using chemostats, we measure alkyl nitrates formed under nitrate limited conditions. We also use triggers and inhibitors of nitric oxide formation to determine if alkyl nitrate formation is affected by changes in NO production. To date, the rates of production of alkyl nitrates in our cultures, lead us to estimate a production rate on the order of femtomolar/day for C1-C3 alkyl nitrates by diatom species in the equatorial Pacific Ocean. This suggests that diatoms may contribute to the overall ocean source of alkyl nitrates; however, it is possible that other types of phytoplankton, such as cyanobacteria, that are more abundant in the open ocean, may contribute to a greater extent.

  7. Novel Approach for Evaluating Secondary Organic Aerosol from Aromatic Hydrocarbons: Unified Method for Predicting Aerosol Composition and Formation.

    Science.gov (United States)

    Li, Lijie; Tang, Ping; Nakao, Shunsuke; Kacarab, Mary; Cocker, David R

    2016-06-21

    Innovative secondary organic aerosol (SOA) composition analysis methods normalizing aerosol yield and chemical composition on an aromatic ring basis are developed and utilized to explore aerosol formation from oxidation of aromatic hydrocarbons. SOA yield and chemical composition are revisited using 15 years of University of California, Riverside/CE-CERT environmental chamber data on 17 aromatic hydrocarbons with HC:NO ranging from 11.1 to 171 ppbC:ppb. SOA yield is redefined in this work by normalizing the molecular weight of all aromatic precursors to the molecular weight of the aromatic ring [Formula: see text], where i is the aromatic hydrocarbon precursor. The yield normalization process demonstrates that the amount of aromatic rings present is a more significant driver of aerosol formation than the vapor pressure of the precursor aromatic. Yield normalization also provided a basis to evaluate isomer impacts on SOA formation. Further, SOA elemental composition is explored relative to the aromatic ring rather than on a classical mole basis. Generally, four oxygens per aromatic ring are observed in SOA, regardless of the alkyl substitutes attached to the ring. Besides the observed SOA oxygen to ring ratio (O/R ∼ 4), a hydrogen to ring ratio (H/R) of 6 + 2n is observed, where n is the number of nonaromatic carbons. Normalization of yield and composition to the aromatic ring clearly demonstrates the greater significance of aromatic ring carbons compared with alkyl carbon substituents in determining SOA formation and composition. PMID:27177154

  8. 40 CFR 721.9892 - Alkylated urea.

    Science.gov (United States)

    2010-07-01

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

  9. Methods of making alkyl esters

    Science.gov (United States)

    Elliott, Brian

    2010-08-03

    A method comprising contacting an alcohol, a feed comprising one or more glycerides and equal to or greater than 2 wt % of one or more free fatty acids, and a solid acid catalyst, a nanostructured polymer catalyst, or a sulfated zirconia catalyst in one or more reactors, and recovering from the one or more reactors an effluent comprising equal to or greater than about 75 wt % alkyl ester and equal to or less than about 5 wt % glyceride.

  10. How non-conventional feedstocks will affect aromatics technologies

    Energy Technology Data Exchange (ETDEWEB)

    Koehler, E. [Clariant Produkte (Deutschland) GmbH, Muenchen (Germany)

    2013-11-01

    The abundance of non-conventional feedstocks such as coal and shale gas has begun to affect the availability of traditional base chemicals such as propylene and BTX aromatics. Although this trend is primarily fueled by the fast growing shale gas economy in the US and the abundance of coal in China, it will cause the global supply and demand situation to equilibrate across the regions. Lower demand for gasoline and consequently less aromatics rich reformate from refineries will further tighten the aromatics markets that are expected to grow at healthy rates, however. Refiners can benefit from this trend by abandoning their traditional fuel-oriented business model and becoming producers of petrochemical intermediates, with special focus on paraxylene (PX). Cheap gas from coal (via gasification) or shale reserves is an advantaged feedstock that offers a great platform to make aromatics in a cost-competitive manner, especially in regions where naphtha is in short supply. Gas condensates (LPG and naphtha) are good feedstocks for paraffin aromatization, and methanol from coal or (shale) gas can be directly converted to BTX aromatics (MTA) or alkylated with benzene or toluene to make paraxylene. Most of today's technologies for the production and upgrading of BTX aromatics and their derivatives make use of the unique properties of zeolites. (orig.)

  11. Ni-catalyzed alkylative dimerization of vinyl grignard reagents using alkyl fluorides.

    Science.gov (United States)

    Terao, Jun; Watabe, Hiroyasu; Kambe, Nobuaki

    2005-03-23

    Alkyl halides underwent unique cross-coupling reaction with vinylmagnesium chloride in the presence of Ni catalyst to give 2-alkyl-3-butenyl Grignard reagent (1) in high yields. This reaction proceeded efficiently at 25 degrees C in THF using primary and secondary alkyl fluorides. On the other hand, PhCH=CHMgBr gave double alkylative vinyl coupling product 4 in good yield as the sole coupling product. Alkyl fluorides react as the most suitable alkylating reagent in comparison to the corresponding chlorides, bromides, and iodides. PMID:15771474

  12. Ring closing and opening reactions leading to aza-polycyclic aromatic compounds

    OpenAIRE

    Kethe, Anila; Li, Ang; Klumpp, Douglas A.

    2012-01-01

    A series of functionalized aza-polycyclic aromatic compounds were prepared by a superacid-promoted ring closing and opening reaction cascade. A reaction mechanism is proposed, which involves reactive dicationic intermediates. A key step in the conversions involves ipso protonation of an aryl group and elimination of an alkyl phenyl group.

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

    OpenAIRE

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

    2012-01-01

    If there were a stigma scale for chemotherapy, alkylating agents would be ranked at the top of the list. The chemical term alkylation is associated with nonselective toxicity, an association that dates back to the use of nitrogen mustards during World War I as chemical warfare agents. That this stigma persists and extends to compounds that, through selectivity, attempt to “tame” the indiscriminate destructive potential of alkylation is the subject of this review. Selective alkylation, as it i...

  14. 40 CFR 721.8673 - [(Disubstituted phenyl)]azo dihydro hydroxy alkyl oxo alkyl-substituted-pyridines (generic name).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false azo dihydro hydroxy alkyl oxo alkyl... Significant New Uses for Specific Chemical Substances § 721.8673 azo dihydro hydroxy alkyl oxo alkyl...) The chemical substances identified generically as azo dihydro hydroxy alkyl oxo...

  15. Alkyl aryl ethers in lignite solubilization. 2. Analysis of oil fractions

    Energy Technology Data Exchange (ETDEWEB)

    Mastral, A.M.; Cebolla, V.L.; Gavilan, J.M.

    1985-03-01

    The FT-I.R. and /sup 1/H N.M.R. spectroscopic analyses of oils or maltenes from a Spanish lignite (Utrillas, Teruel), are reported. These oils were obtained by depolymerization with alkyl aromatic ethers (anisole, 3-methyl anisole and 1,3-dimethoxybenzene) catalyzed by Lewis acids ZnCl/sub 2/, AlCl/sub 3/, SbCl/sub 3/ and BF/sub 3/ (as boron trifluoride etherate), at atmospheric pressure and temperatures <220 C. Bands due to aromatic ethers in the I.R. and N.M.R. spectra of the oils obtained by depolymerization indicate solvent incorporation. Oils obtained by direct lignite extraction showed 25% aromatic H and some H (approximately 3%) without OH groups. These appeared in some oils obtained by depolymerization with AlCl/sub 3/ and were due to secondary reactions with the aromatic extract. Oils derived from processes with good yields showed increases in aromaticity. The extent of substitution of aromatic rings in oils obtained by depolymerization was less than for oils directly extracted. All the oils studied show a low degree of condensation. 15 references.

  16. C-Alkylation by Hydrogen Autotransfer Reactions.

    Science.gov (United States)

    Obora, Yasushi

    2016-04-01

    The development of practical, efficient, and atom-economical methods for the formation of carbon-carbon bonds remains a topic of considerable interest in current synthetic organic chemistry. In this review, we have summarized selected topics from the recent literature with particular emphasis on C-alkylation processes involving hydrogen transfer using alcohols as alkylation reagents. This review includes selected highlights concerning recent progress towards the modification of catalytic systems for the α-alkylation of ketones, nitriles, and esters. Furthermore, we have devoted a significant portion of this review to the methylation of ketones, alcohols, and indoles using methanol. Lastly, we have also documented recent advances in β-alkylation methods involving the dimerization of alcohols (Guerbet reaction), as well as new developments in C-alkylation methods based on sp (3) C-H activation. PMID:27573136

  17. Photochemically induced oscillations of aromatic pentazadienes

    Energy Technology Data Exchange (ETDEWEB)

    Kunz, T.; Hahn, C.; Wokaun, A. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-06-01

    Aromatic pentazadienes are used to enhance the laser induced ablation of standard polymers with low absorption in the UV. Therefore the photochemistry of substituted 1,5-diaryl-3-alkyl-1,4-pentazadiene monomers was studied with a pulsed excimer laser as irradiation source. The net photochemical reaction proceeds in an overall one-step pathway A{yields}B. Quantum yields for the laser decomposition were determined to be up to 10%. An oscillating behaviour of the absorption was found during the dark period following the irradiation. The temperature dependence of this dark reaction has been studied. An attempt to model this behaviour in terms of a non-linear coupling between heat released, heat transfer, and reaction kinetics will be described. (author) 4 figs., 4 refs.

  18. Surface reactivity and layer analysis of chemisorbed reaction films in the surface-chemical environment of alkyl octadecenoates

    Indian Academy of Sciences (India)

    R B Choudhary; O N Anand; O S Tyagi

    2009-05-01

    Studies on surface reactivity of substrate iron (Fe-particles) were made in the tribo-chemical environment of alkyl octadecenoates. Two alkyl octadecenoates namely ethyl octadecenoate and methyl 12-hydroxy octadecenoate, slightly different in their chemical nature, were taken for preparing the chemisorbed reaction films (CRF) at the temperature 100 ± 5°C. The reaction products collected in the composite (amorphous) phase were isolated into three different solvent-soluble fractions (sub-layer films) using polar solvents of increasing polar strength. The FTIR analysis of these films showed that these were primarily organic in nature and were composed of alkyl and/or aryl hydroxy ethers, unsaturated hydroxy ketones, and aromatic structures chemically linked with iron surface. These reaction films also contained large amount of iron (Fe). Further, these film fractions also showed varying thermal behaviour during thermal decomposition in the temperature range of 50-800°C when thermally evaluated in the nitrogen environment.

  19. Superconductivity in aromatic hydrocarbons

    International Nuclear Information System (INIS)

    Highlights: • Aromatic superconductor is one of core research subjects in superconductivity. Superconductivity is observed in certain metal-doped aromatic hydrocarbons. Some serious problems to be solved exist for future advancement of the research. This article shows the present status of aromatic superconductors. - Abstract: ‘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

  20. Reaction of Lithium Diethylamide with an Alkyl Bromide and Alkyl Benzenesulfonate: Origins of Alkylation, Elimination, and Sulfonation

    OpenAIRE

    Gupta, Lekha; Ramírez, Antonio; Collum, David B.

    2010-01-01

    A combination of NMR, kinetic, and computational methods are used to examine reactions of lithium diethylamide in tetrahydrofuran (THF) with n-dodecyl bromide and n-octyl benzenesulfonate. The alkyl bromide undergoes competitive SN2 substitution and E2 elimination in proportions independent of all concentrations except for a minor medium effect. Rate studies show that both reactions occur via trisolvated-monomer-based transition structures. The alkyl benzenesulfonate undergoes competitive SN2...

  1. PREPARATION OF ALKYL HALIDES VIA ORGANOTELLURIUMS

    OpenAIRE

    チカマツ, キヨフミ; オオツボ, テツオ; オグラ, フミオ; ヤマグチ, ハチロウ; Kiyofumi, CHIKAMATSU; Tetsuo, OTSUBO; Fumio, OGURA; Hachiro, YAMAGUCHI

    1982-01-01

    The conversion of phenyltelluroalkanes to haloalkanes was studied in connection with the homologation of alkyl halides. Similar reactions of 1,1-bis(phenyltelluro)alkanes provided a new synthetic method of aldehydes.

  2. Thermally induced alkylation of diamond.

    Science.gov (United States)

    Hoeb, Marco; Auernhammer, Marianne; Schoell, Sebastian J; Brandt, Martin S; Garrido, Jose A; Stutzmann, Martin; Sharp, Ian D

    2010-12-21

    We present an approach for the thermally activated formation of alkene-derived self-assembled monolayers on oxygen-terminated single and polycrystalline diamond surfaces. Chemical modification of the oxygen and hydrogen plasma-treated samples was achieved by heating in 1-octadecene. The resulting layers were characterized using X-ray photoelectron spectroscopy, thermal desorption spectroscopy, atomic force microscopy, Fourier transform infrared spectroscopy, and water contact angle measurements. This investigation reveals that alkenes selectively attach to the oxygen-terminated sites via covalent C-O-C bonds. The hydrophilic oxygen-terminated diamond is rendered strongly hydrophobic following this reaction. The nature of the process limits the organic layer growth to a single monolayer, and FTIR measurements reveal that such monolayers are dense and well ordered. In contrast, hydrogen-terminated diamond sites remain unaffected by this process. This method is thus complementary to the UV-initiated reaction of alkenes with diamond, which exhibits the opposite reactivity contrast. Thermal alkylation increases the range of available diamond functionalization strategies and provides a means of straightforwardly forming single organic layers in order to engineer the surface properties of diamond. PMID:21090790

  3. Alkyl aryl ethers in lignite solubilization 1. Study of the process

    Energy Technology Data Exchange (ETDEWEB)

    Mastral, A.M.; Cebolla, V.L.; Gavilan, J.M.

    1984-10-01

    The chemistry of solubilization of a lignite has been investigated with anisole, 3-methyl anisole and 1,3dimethoxybenzene catalysed by SbCl/sub 3/, ZnCl/sub 2/, AlCl/sub 3/ and BF/sub 3/ as boron trifluoride etherate, at atmospheric pressure and temperatures <220/sup 0/C. 60% of lignite was solubilized in a toluene-ethanol azeotropic mixture. During the process, the solvent is incorporated as an alkylated substratum. The yield increased with activity of the aromatic ether ring and catalyst acidity.

  4. Alkyl aryl ethers in lignite solubilization. 1. Study of the process

    Energy Technology Data Exchange (ETDEWEB)

    Mastral, A.M.; Cebolla, V.L.; Gavilan, J.M.

    1984-10-01

    The chemistry of solubilization of a lignite has been investigated with anisole, 3-methyl anisole and 13-dimethoxybenzene catalysed by SbCl/sub 3/, ZnCl/sub 2/, AlCl/sub 3/ and BF/sub 3/ as boron trifluoride etherate, at atmospheric pressure and temperatures <220 C. 60% of lignite was solubilized in a toluene-ethanol azeotropic mixture. During the process, the solvent is incorporated as an alkylated substratum. The yield increased with activity of the aromatic ether ring and catalyst acidity. 14 references.

  5. Experimental verifications on chemical carcinogenesis, a bifunctional alkylation between DNA interstrands

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    It is evidenced by the filter elution method that two carcinogenic aromatic hydrocarbons, benzo[a]pyrene and dibenzo[a,h]anthracene, two carcinogenic metal salts, beryllium chloride and cadmium chloride, four carcinogenic aromatic amines, 2-aminofluorene, β-naphthylamine, 4-aminobiphenyl and benzidine, can all induce DNA interstrand and DNA-protein cross-link in L1210 culture. However, under the same condition, the corresponding non-carcinogenic compounds, including benzo[k]fluorancene, anthracene, magnesium chloride, zinc chloride, a -naphthylamine, 2-aminobiphenyl and m-toluidine, cannot produce any cross-link adducts. All these results are consistent with the di-region theory that carcinogens are bio-bifunctional alkylation agents. This method can also be used to discriminate carcinogens and non-carcinogens.

  6. Superconductivity in aromatic hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Kubozono, Yoshihiro, E-mail: kubozono@cc.okayama-u.ac.jp [Research Laboratory for Surface Science, Okayama University, Okayama 700-8530 (Japan); Research Center of New Functional Materials for Energy Production, Storage and Transport, Okayama University, Okayama 700-8530 (Japan); Japan Science and Technology Agency, ACT-C, Kawaguchi 332-0012 (Japan); Goto, Hidenori; Jabuchi, Taihei [Research Laboratory for Surface Science, Okayama University, Okayama 700-8530 (Japan); Yokoya, Takayoshi [Research Laboratory for Surface Science, Okayama University, Okayama 700-8530 (Japan); Research Center of New Functional Materials for Energy Production, Storage and Transport, Okayama University, Okayama 700-8530 (Japan); Kambe, Takashi [Department of Physics, Okayama University, Okayama 700-8530 (Japan); Sakai, Yusuke; Izumi, Masanari; Zheng, Lu; Hamao, Shino; Nguyen, Huyen L.T. [Research Laboratory for Surface Science, Okayama University, Okayama 700-8530 (Japan); Sakata, Masafumi; Kagayama, Tomoko; Shimizu, Katsuya [Center of Science and Technology under Extreme Conditions, Osaka University, Osaka 560-8531 (Japan)

    2015-07-15

    Highlights: • Aromatic superconductor is one of core research subjects in superconductivity. Superconductivity is observed in certain metal-doped aromatic hydrocarbons. Some serious problems to be solved exist for future advancement of the research. This article shows the present status of aromatic superconductors. - Abstract: ‘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 (K{sub x}picene, five benzene rings). Its superconducting transition temperatures (T{sub c}’s) were 7 and 18 K. Recently, we found a new superconducting K{sub x}picene phase with a T{sub c} as high as 14 K, so we now know that K{sub x}picene possesses multiple superconducting phases. Besides K{sub x}picene, we discovered new superconductors such as Rb{sub x}picene and Ca{sub x}picene. A most serious problem is that the shielding fraction is ⩽15% for K{sub x}picene and Rb{sub x}picene, 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 T{sub c} that is clearly

  7. Effect of ZSM-5 Acidity on Aromatic Product Selectivity during Upgrading of Pine Pyrolysis Vapors

    Energy Technology Data Exchange (ETDEWEB)

    Engtrakul, Chaiwat; Mukarakate, Calvin; Starace, Anne K.; Magrini, Kimberly A.; Rogers, Allyson K.; Yung, Matthew M.

    2016-07-01

    The impact of catalyst acidity on the selectivity of upgraded biomass pyrolysis products was studied by passing pine pyrolysis vapors over five ZSM-5 catalysts of varying acidity at 500 degrees C. The SiO2-to-Al2O3 ratio (SAR) of the ZSM-5 zeolite was varied from 23 to 280 to control the acidity of the catalyst and the composition of upgraded products. The upgraded product stream was analyzed by GCMS. Additionally, catalysts were characterized using temperature programmed desorption, diffuse-reflectance FTIR spectroscopy, N2 physisorption, and X-ray diffraction. The results showed that the biomass pyrolysis vapors were highly deoxygenated to form a slate of aromatic hydrocarbons over all of the tested ZSM-5 catalysts. As the overall acidity of the ZSM-5 increased the selectivity toward alkylated (substituted) aromatics (e.g., xylene, dimethyl-naphthalene, and methyl-anthracene) decreased while the selectivity toward unsubstituted aromatics (e.g., benzene, naphthalene, and anthracene) increased. Additionally, the selectivity toward polycyclic aromatic compounds (2-ring and 3-ring) increased as catalyst acidity increased, corresponding to a decrease in acid site spacing. The increased selectivity toward less substituted polycyclic aromatic compounds with increasing acidity is related to the relative rates of cyclization and alkylation reactions within the zeolite structure. As the acid site concentration increases and sites become closer to each other, the formation of additional cyclization products occurs at a greater rate than alkylated products. The ability to adjust product selectivity within 1-, 2-, and 3-ring aromatic families, as well as the degree of substitution, by varying ZSM-5 acidity could have significant benefits in terms creating a slate of upgraded biomass pyrolysis products to meet specific target market demands.

  8. Polycyclic Aromatic Compounds as Anticancer Agents: Synthesis and Biological Evaluation of Methoxy Dibenzofluorene Derivatives

    Directory of Open Access Journals (Sweden)

    BimalKrishnaBanik

    2014-08-01

    Full Text Available Synthesis of a new methoxy dibenzofluorene through alkylation, cyclodehydration and aromatization in a one-pot operation is achieved for the first time. Using this hydrocarbon, a few derivatives are prepared through aromatic nitration, catalytic hydrogenation, coupling reaction with a side chain and reduction. The benzylic position of this hydrocarbon with the side chain is oxidized and reduced. Some of these derivatives have demonstrated excellent antitumor activities in vitro. This study confirms antitumor activity depends on the structures of the molecules.

  9. Classical density functional theory & simulations on a coarse-grained model of aromatic ionic liquids.

    Science.gov (United States)

    Turesson, Martin; Szparaga, Ryan; Ma, Ke; Woodward, Clifford E; Forsman, Jan

    2014-05-14

    A new classical density functional approach is developed to accurately treat a coarse-grained model of room temperature aromatic ionic liquids. Our major innovation is the introduction of charge-charge correlations, which are treated in a simple phenomenological way. We test this theory on a generic coarse-grained model for aromatic RTILs with oligomeric forms for both cations and anions, approximating 1-alkyl-3-methyl imidazoliums and BF₄⁻, respectively. We find that predictions by the new density functional theory for fluid structures at charged surfaces are very accurate, as compared with molecular dynamics simulations, across a range of surface charge densities and lengths of the alkyl chain. Predictions of interactions between charged surfaces are also presented. PMID:24718295

  10. Silver-catalyzed coupling reactions of alkyl halides with indenyllithiums

    OpenAIRE

    Someya, Hidenori; Yorimitsu, Hideki; Oshima, Koichiro

    2010-01-01

    Coupling reactions of tertiary and secondary alkyl halides with indenyllithiums proceeded effectively in the presence of a catalytic amount of silver bromide to provide tertiary- and secondary-alkyl-substituted indene derivatives in good yields.

  11. Outlook for the U.S. alkylation industry

    International Nuclear Information System (INIS)

    Alkylation has long been recognized in the refining industry as one of the best options to convert refinery olefins into valuable, clean, high octane blending components. In fact, refinery alkylation is a preferred source of blending stocks for reformulated gasoline. However, the hydrofluoric acid (HF) alkylation process and, to a lesser extent, the sulfuric acid (SA) process have come under increasing pressure in the US due to safety and environmental concerns. This paper examines the current outlook for the US alkylation industry including: key trends and driving forces in the industry, the impact of environmental issues on both HF and SA alkylation, US alkylation supply/demand forecast including the outlook for oxygenates, how US refines will respond to the increased demand and restricted supply for alkylates, and the outlook for new solid acid alkylation (SAC) technology

  12. Partition of polycyclic aromatic hydrocarbons on organobentonites

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A series of organobentonites synthesized by exchanging organiccation such as dodecyltri-methylammonium (DTMA),benzyldimethyltetradecylammonium (BDTDA), cetyltrimethyl-ammonium (CTMA), octodeyltrimethylammonium (OTMA) on bentonite. The optimal condition, properties and mechanisms for the organobentonites to sorb phenanthrene, anthracene, naphthalene, acenaphthene in water were investigated in detail. The partition behavior was determined for four polycyclic aromatic hydrocarbons (PAHs), such as naphthalene, phenanthrene, anthracene and acenaphthene, from water to a series of organobentonites. The interlayer spacings and organic carbon contents of organobentonites, removal rate and sorption capacities for organobentonites to treat phenanthrene,anthracene, naphthalene, acenaphthene were correlated to the length of alkyl chains and the amounts of cation surfactant exchanged on Foundation item: the bentonite. Phenanthrene, anthracene, naphthalene, and acenaphthene sorption to organobentonites were characterized by linear isotherms, indicating solute partition between water and the organic phase composed of the large alkyl functional groups of quaternary ammonium cations. PAHs distribution coefficients (Kd)between organobentonites and water were proportional to the organic carbon contents of organobentonites. However, the partition coefficients (Koc) were nearly constants for PAHs in the system of organobentonite-water. The Koc of phenanthrene, anthracene,naphthalene, acenaphthene were 2.621x105, 2.106x105, 2.247x104,5.085x104, respectively. The means Koc values on the organobentonites are about ten to twenty times larger than the values on the soils/sediments, what is significant prerequisite for organobentonite to apply to remediation of pollution soil and groundwater. The sorption mechanism was also evaluated from octanol-water partition coefficients and aqueous solubility of PAHs. The correlations between lgKoc and 1gkow, 1gKoc and 1gS for PAHs in the system of water

  13. 40 CFR 721.575 - Substituted alkyl halide.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Substituted alkyl halide. 721.575... Substances § 721.575 Substituted alkyl halide. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as substituted alkyl halide (PMN P-83-1222)...

  14. 40 CFR 721.10053 - Alkyl silane methacrylate (generic).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Alkyl silane methacrylate (generic... Specific Chemical Substances § 721.10053 Alkyl silane methacrylate (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as alkyl...

  15. The Synthesis of 6-Alkyl-5-Fluorouracil Derivatives

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    6-alkyl-5-fluorouracil derivatives (5a~5f) were synthesized by facile alkylation of lithiation of 5-fluorouracil derivatives with mthyl iodide (MeI) or alkyl trifluoromethanesulfonate (ROTf) in yield of 42~58%. We found that the methylated product was ethyl-substituted derivatives, not methyl-substituted derivatives.

  16. IONIC LIQUID-CATALYZED ALKYLATION OF ISOBUTANE WITH 2-BUTENE

    Science.gov (United States)

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

  17. Synthesis and characterization of chitosan alkyl urea.

    Science.gov (United States)

    Wang, Jing; Jiang, Ji-Zhou; Chen, Wei; Bai, Zheng-Wu

    2016-07-10

    Chitosan is a versatile material employed for various purposes in many fields including the development of chiral stationary phases for enantioseparation. Chitosan alkyl urea is a kind of intermediate used to prepare enantioseparation materials. In order to synthesize the intermediates, in the present work, a new way to prepare chitosan alkyl urea has been established: chitosan was first reacted with methyl chloroformate yielding N-methoxyformylated chitosan, which was then converted to chitosan alkyl urea through amine-ester exchange reaction. With a large excess of methyl chloroformate and primary amine of low stereohindrance, the amino group in chitosan could be almost completely converted to ureido group. The as-prepared chitosan alkyl urea derivatives were characterized by IR, (1)H NMR, (13)C NMR,(1)H-(1)H COSY and (1)H-(13)C HSQC NMR spectra. The chemical shifts of hydrogen and carbon atoms of glucose unit were assigned. It was found that the degree of substitution was obviously lower if cyclopropyl amine, aniline, tert-butyl amine and diethyl amine were used as reactants for the amine-ester exchange reaction. The reason was explained with the aid of theoretical calculations. PMID:27106154

  18. Polypyrrole Doped with Alkyl Benzene Sulphonates

    DEFF Research Database (Denmark)

    Bay, Lasse; Mogensen, Naja; Skaarup, Steen;

    2002-01-01

    The properties of polypyrrole (PPy) are to a large extent determined by the condition of synthesis and especially by the counterion incorporated as dopant during synthesis. In this work, PPy doped with different alkyl benzenesulfonates are compared. The polymer films are prepared by constant curr...

  19. Performance of HZSM-5 as Catalyst for Alkylation of Methyl naphthalene with Methanol in Supercritical Phase

    Institute of Scientific and Technical Information of China (English)

    BAI Xue-feng; WU Wei; HU Hao-quan

    2005-01-01

    The alkylation of methylnaphthalene(MN) with methanol in the presence of HZSM-5 is a promising route for producing 2,6-dimetylnaphthalene(2,6-DMN) with a high selectivity. However, the conversion of MN is very low and the catalyst will be deactivated rapidly with increasing time on stream. In this study, the effects of the reaction pressure on the reactivity, selectivity and life of the catalyst of alkylation of MN over HZSM-5 modified by BaO were investigated. It was observed that with the enhancement of pressure, the conversion of MN increased, but the selectivity of 2,6-DMN kept unchanged, which was about 40%-42%. When the alkylation was carried out under a supercritical condition, the conversion of MN was 3-6 times higher and the life of catalyst was 25-30 times longer than those at an ambient pressure. The thermogravimetric analyses of the deactivated catalysts at different reaction pressures indicate that the amount of coke deposited on the catalysts was about 10% to 12 %, and the coke-burning reactions mainly took place in a temperature range from 720 to 860 K, and the apparent activation energies of the coke-burning catalysts at 0. 1 MPa( 10 h) and 7. 6 MPa( 108 h) were, respectively, 65.90 and 84. 72 kJ/mol. It is concluded from the results that the supercritical condition is advantageous to enhancing the conversion of alkylation and extraction in situ, and to transporting those high molecular-weight poly-aromatic compounds so as to extend the catalyst life successively.

  20. FTIR SPECTRA OF ADSORBED PYRIDINE OVER HIGH SILICA USY ,TI-USY AND FE-TI-USY ZEOLITE AND ALKYLATION OF O-TOLUIDINE OVER THEM.

    OpenAIRE

    K.U.GORE

    2013-01-01

    Alkylated aromatic amines are industrially very important. Ortho alkylatedamines are used as intermedites for producing dyes , insecticides, resins ,Stabilizers,rubber processing chemicals and as a liquid fuel in missiles. The usefulnessof the zeolite due to its modified stural changes can be tested by studing the change inits role as a catylist in carrying out the chemical reactions as compared to its originalsample. zeolite- Y due to its 3D pore structure is the single largest Zeolite used ...

  1. Efficient, "tin-free" radical cyclization to aromatic systems. synthesis of 5,6,8,9,10,11-hexahydroindolo[2,1-a]isoquinolines.

    Science.gov (United States)

    Menes-Arzate, Martha; Martínez, Roberto; Cruz-Almanza, Raymundo; Muchowski, Joseph M; Osornio, Yazmin M; Miranda, Luis D

    2004-05-28

    Efficient radical cyclization of alkyl iodides to various aromatic systems including pyrrole, indole, isoquinolone, pyridone, and benzene, mediated by dicumyl peroxide, is described. The methodology was used to provide access to 5,6,8,9,10,11-hexahydroindolo[2,1-a]isoquinoline derivatives. PMID:15153044

  2. Ultra-bright alkylated graphene quantum dots

    Science.gov (United States)

    Feng, Lan; Tang, Xing-Yan; Zhong, Yun-Xin; Liu, Yue-Wen; Song, Xue-Huan; Deng, Shun-Liu; Xie, Su-Yuan; Yan, Jia-Wei; Zheng, Lan-Sun

    2014-10-01

    Highly efficient and stable photoluminescence (PL) are urgently desired for graphene quantum dots (GQDs) to facilitate their prospective applications as optical materials. Here, we report the facile and straightforward synthesis of alkylated graphene quantum dots (AGQDs) via the solvothermal reaction of propagatively alkylated graphene sheets (PAGenes). In contrast to most GQDs reported so far, the synthesized AGQDs process pH-independent and ultra-bright PL with a relative quantum yield of up to 65%. Structural and chemical composition characterization demonstrated that the synthesized AGQDs are nearly oxygen-defect-free with alkyl groups decorated on edges and basal plane, which may contribute to their greatly improved pH tolerance and high quantum efficiency. The photocatalytic performance of AGQDs-P25 nanocomposites was evaluated by the degradation of Rhodamine B under visible light. The photocatalytic rate is ca. 5.9 times higher than that of pure P25, indicating that AGQDs could harness the visible spectrum of sunlight for energy conversion or environmental therapy.Highly efficient and stable photoluminescence (PL) are urgently desired for graphene quantum dots (GQDs) to facilitate their prospective applications as optical materials. Here, we report the facile and straightforward synthesis of alkylated graphene quantum dots (AGQDs) via the solvothermal reaction of propagatively alkylated graphene sheets (PAGenes). In contrast to most GQDs reported so far, the synthesized AGQDs process pH-independent and ultra-bright PL with a relative quantum yield of up to 65%. Structural and chemical composition characterization demonstrated that the synthesized AGQDs are nearly oxygen-defect-free with alkyl groups decorated on edges and basal plane, which may contribute to their greatly improved pH tolerance and high quantum efficiency. The photocatalytic performance of AGQDs-P25 nanocomposites was evaluated by the degradation of Rhodamine B under visible light. The

  3. Synthesis and photophysical properties of 1, 4-disubstituted naphthyloxymethyl--alkyl naphthimido-1,2,3-triazole

    Indian Academy of Sciences (India)

    J Ramchander; N Rameshwar; T Sheshashena Reddy; Gajula Raju; A Ram Reddy

    2014-07-01

    Regioselective synthesis of a series of 1,4-disubstituted of naphthoxymethyl-N-alkyl naphthalimide-1,2,3-triazoles employing click reaction is presented. Highly selective and efficient copper(I)-catalysed 1,3-dipolar cyclo addition between 1-naphthylpropargylic ether and azido alkyl naphthalimides yielded the title compounds in 74% to 94%. The structure of all the new 1,2,3-triazoles was characterized by 1HNMR, 13C NMR, IR and Mass. The electronic absorption and emission studies revealed that the light absorbing and emitting chromophore is the naphthoxy moiety. There is no extensive delocalization of aromatic π-electrons in the active chromophore which exhibited lower quantum yields and lower Stokes shifts.

  4. Zinc-thiolate complexes of the bis(pyrazolyl)(thioimidazolyl)hydroborate tripods for the modeling of thiolate alkylating enzymes.

    Science.gov (United States)

    Ji, Mian; Benkmil, Boumahdi; Vahrenkamp, Heinrich

    2005-05-16

    The new tripod ligands bis(pyrazolyl)(3-tert-butyl-2-thioimidazol-1-yl)hydroborate (L(1)) and bis(pyrazolyl)(3-isopropyl-2-thioimidazol-1-yl)hydroborate (L(2)), together with zinc nitrate or zinc chloride and the corresponding thiolates, have yielded a total of 17 zinc-thiolate complexes. These comprise aliphatic as well as aromatic thiolates and a cysteine derivative. Structure determinations have confirmed the tetrahedral ZnN(2)S(2) coordination in the complexes. Upon reaction with methyl iodide, the species L(1).Zn-SR are slowly converted to L(1).Zn-I and the free thioethers CH(3)SR. A kinetic analysis has shown these alkylations to be about 1 order of magnitude slower than those of the tris(pyrazolyl)borate complexes Tp(Ph,Me)Zn-SR. Alkylations with trimethyl phosphate were found to proceed very slowly even in DMSO at 80 degrees C. PMID:15877434

  5. Alkyl- and fluoroalkyltrialkoxysilanes for wettability modification

    Energy Technology Data Exchange (ETDEWEB)

    Dopierala, Katarzyna, E-mail: katarzyna.dopierala@put.poznan.pl [Institute of Chemical Technology and Engineering, Poznan University of Technology, Pl. Marii Skłodowskiej-Curie 2, Poznań 60-965 (Poland); Maciejewski, Hieronim [Poznań Science and Technology Park, Rubież 46, Poznań 61-612 (Poland); Faculty of Chemistry, Adam Mickiewicz University, Grunwaldzka 6, Poznań 60-780 (Poland); Karasiewicz, Joanna [Poznań Science and Technology Park, Rubież 46, Poznań 61-612 (Poland); Prochaska, Krystyna [Institute of Chemical Technology and Engineering, Poznan University of Technology, Pl. Marii Skłodowskiej-Curie 2, Poznań 60-965 (Poland)

    2013-10-15

    Alkyl- and fluoroalkyltriethoxysilanes were investigated as potential surface modifiers. Many aspects concerning trialkoxysilanes were discussed, starting from hydrolysis of silanes in water solutions, the effect of this hydrolysis on the surface tension, wettability of the modified surface to the morphology of the modified surface. Surface tension and contact angle measurements as well as scanning electron microscopy were used to characterise alkyl- and fluoroalkyltriethoxysilanes and their ability to modify the wettability of glass. The effect of such modification was superhydrophobic surface with high values of contact angles. Superhydrophobic behaviour was observed as a result of two-step modification providing increased surface roughness thanks to the use of different size silica particles and surface chemical modification with fluorosilane molecules.

  6. Polyimidazoles via aromatic nucleophilic displacement

    Science.gov (United States)

    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.

  7. Lignin peroxidase oxidation of aromatic compounds in systems containing organic solvents.

    Science.gov (United States)

    Vazquez-Duhalt, R; Westlake, D W; Fedorak, P M

    1994-02-01

    Lignin peroxidase from Phanerochaete chrysosporium was used to study the oxidation of aromatic compounds, including polycyclic aromatic hydrocarbons and heterocyclic compounds, that are models of moieties of asphaltene molecules. The oxidations were done in systems containing water-miscible organic solvents, including methanol, isopropanol, N, N-dimethylformamide, acetonitrile, and tetrahydrofuran. Of the 20 aromatic compounds tested, 9 were oxidized by lignin peroxidase in the presence of hydrogen peroxide. These included anthracene, 1-, 2-, and 9-methylanthracenes, acenaphthene, fluoranthene, pyrene, carbazole, and dibenzothiophene. Of the compounds studied, lignin peroxidase was able to oxidize those with ionization potentials of stability characteristics of lignin peroxidase were determined by using pyrene as the substrate in systems containing different amounts of organic solvent. Benzyl alkylation of lignin peroxidase improved its activity in a system containing water-miscible organic solvent but did not increase its resistance to inactivation at high solvent concentrations. PMID:16349176

  8. Examining spatial patterns in polycyclic aromatic compounds measured in stream macroinvertebrates near a small subarctic oil and gas operation.

    Science.gov (United States)

    Korosi, J B; Eickmeyer, D C; Chin, K S; Palmer, M J; Kimpe, L E; Blais, J M

    2016-03-01

    The Cameron River runs through a small, remote petrochemical development in the Cameron Hills (Northwest Territories, Canada). In order to evaluate the exposure of aquatic biota to contaminants from oil and gas activities, we measured polycyclic aromatic compounds (PACs) in macroinvertebrates collected from sites and tributaries along the Cameron River, including upstream and downstream of the development, and sites located near drilled wells (developed). Macroinvertebrate tissue PAC burdens ranged from 0.2-2.8 μg g(-1) lipid for unsubstituted compounds, and from 4.2-63.2 μg g(-1) lipid for alkylated compounds, relatively low compared to similar studies from more industrialized regions in North America. There was no significant difference in tissue PAC burdens between upstream, downstream, or developed sites (p = 0.12), although alkyl PACs in five out of seven developed sites were higher than the regional average. Petrogenic PACs were dominant in most samples, including alkyl fluorines, alkyl phenanthrene/anthracenes, and alkyl dibenzothiophenes. Minimal changes in PAC composition in macroinvertebrate tissues were detected along the Cameron River, with the exception of the two sites furthest downstream that had high concentrations of C3-C4 naphthalene. Overall, our results suggest that oil and gas development in the Cameron Hills has not resulted in substantial increases in PAC bioaccumulation in stream macroinvertebrates, although the potential that alkyl naphthalenes are being transported downstream from the development warrants further attention. PMID:26911593

  9. Selective production of xylenes from alkyl-aromatics and heavy reformates over dual-zeolite catalyst

    Czech Academy of Sciences Publication Activity Database

    Ali, S. A.; Aitani, A.; Čejka, Jiří; Al-Khattaf, S.

    2015-01-01

    Roč. 243, APR 2015 (2015), s. 118-127. ISSN 0920-5861 R&D Projects: GA ČR GBP106/12/G015 Institutional support: RVO:61388955 Keywords : transalkylation * mordenite * xylenes Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.893, year: 2014

  10. Radiolytic crosslinking and chain scission in aliphatic and alkyl-aromatic polyamides—II

    Science.gov (United States)

    Lyons, Bernard J.; Glover, Leon C.

    Regression analysis of the radiation parameters of nine aliphatic polyamides exposed to ionizing radiation leads to the conclusion that the decline in the ratio of chain scission to crosslinking in higher aliphatic polyamides is best related to the linear increase in the methylene content of, or the number of methylene groups in, the polyamide repeat unit. G(crosslink) [ G(X)] and G(chain scission) [ G(CS)] values, however, do not correlate well with either of these parameters. Rather it is found that the major determinant of yields [about 80-85% of the variation for G(X), 70% for G(CS)] is the number of hydrogen atoms or methylene groups in the amine residue. A minor determinant [15% of the variation for G(X) and 30% for G(CS)] is the number of hydrogen atoms or methylene groups in the acid residue of the repeat unit. Significantly, although there was little sign of a decrease in G(CS) in the higher aliphatic homologues (up to 11 methylene residues per amide group), G(CS) is found to be positively related to the number of methylene groups in the amine residue but negatively related to the number of methylene groups in the acid residue. Thus although the amine residue dominates the radiolytic response, the acid residue plays a critical if lesser role in determining chain scission yields in polyamides. Thus a polyamide with the repeat unit —(CH 2) 3 nCONH(CH 2) nNHCO— would be predicted to have a very low or zero G(CS) and, if n is 10 or more, a G(X) comparable to that of polyethylene. Although, logically, the yields of crosslinks and chain scissions in polyamides would be expected to tend to that of polyethylene as the number of methylene groups in the repeat unit increases, use of two models assuming an exponential trend to the G(X) value characteristic of polyethylene in the analysis did not provide better fits to the data than the simple linear model referred to above. Indeed, the assumption of a significant exponential trend factor led to a marked drop in the goodness of fit.

  11. Aromatic molecules as spintronic devices

    International Nuclear Information System (INIS)

    In this paper, we study the spin-dependent electron transport through aromatic molecular chains attached to two semi-infinite leads. We model this system taking into account different geometrical configurations which are all characterized by a tight binding Hamiltonian. Based on the Green's function approach with a Landauer formalism, we find spin-dependent transport in short aromatic molecules by applying external magnetic fields. Additionally, we find that the magnetoresistance of aromatic molecules can reach different values, which are dependent on the variations in the applied magnetic field, length of the molecules, and the interactions between the contacts and the aromatic molecule

  12. One-pot synthesis of S-alkyl dithiocarbamates via the reaction of N-tosylhydrazones, carbon disulfide and amines.

    Science.gov (United States)

    Sha, Qiang; Wei, Yun-Yang

    2013-09-14

    A new, convenient and efficient transition metal-free synthesis of S-alkyl dithiocarbamates through one-pot reaction of N-tosylhydrazones, carbon disulfide and amines is reported. Tosylhydrazones derived from various aromatic and aliphatic ketones or aldehydes were tested and gave dithiocarbamates in good to excellent yields. The tosylhydrazones can be generated in situ without isolation, which provides a simpler one-pot method to synthesize dithiocarbamates via the reaction of carbonyl compounds, carbon disulfide and amines in the presence of 4-methylbenzenesulfonohydrazide. PMID:23863979

  13. Enzymatic Synthesis of Palm Alkyl Ester Using Dialkyl Carbonate as an Alkyl Donors

    Directory of Open Access Journals (Sweden)

    Roila Awang

    2010-01-01

    Full Text Available Problem statement: Though efficient in terms of reaction yield and time, the chemical approach to synthesizing alkyl ester has drawback such as difficulties in the recovery of glycerol and the need for removal of salt residue. On the other hand, biocatalyst allow for synthesis of specific alkyl esters and easy recovery of glycerol. However, the solvent-free alcoholysis, does not give high conversion. The same problem was also found when ethyl or methyl acetate was used as acyl acceptors. Approach: Lipase catalyzed transesterification of oil and dialkyl carbonate was predicted to give higher conversion in solvent free reaction system. Results: Alkyl esters were synthesized enzymatically to overcome the problems associated with chemical processes. In this study, dialkyl carbonates were used as an alkyl donor for the production of alkyl ester. Nine commercial lipases were tested for their suitability for the reaction system. Among the lipase tested, Novozym 435 was chosen for optimization study because of their higher activity. In a solvent-free reaction system, the ester formation using dialkyl carbonate was 6 times higher than using ethanol and methanol. The effect of various reaction parameters such as temperature, amount of enzyme, organic solvent and structure of substrates were studied to determine optimal condition. The optimal conditions of ester formation were reaction temperature at 60°C, reaction time at 8 h, enzyme amount of 10% (w/w of oil and 0.2% wt added water. Conclusion: Solvent-free lipase catalyzed transesterification of palm kernel oil and dialkyl carbonates gave higher conversion of ester compared to the reaction using short chain alcohol as an alkyl donors.

  14. The effects of CYP1A inhibition on alkyl-phenanthrene metabolism and embryotoxicity in marine medaka (Oryzias melastigma).

    Science.gov (United States)

    Mu, Jingli; Jin, Fei; Wang, Juying; Wang, Ying; Cong, Yi

    2016-06-01

    Alkylated polycyclic aromatic hydrocarbons (alkyl-PAHs) are the predominant form of PAHs in crude oils, of which, 3-5 ring alkyl-PAH may cause dioxin-like toxicity to early life stages of fish. Retene (7-isopropyl-1-methylphenanthrene), a typical alkyl-phenanthrene compound, can be more toxic than phenanthrene, and the mechanism of retene toxicity is likely related to its rapid biotransformation by cytochrome P450 (CYP) enzymes to metabolites with a wide array of structures and potential toxicities. Here, we investigated how α-naphthoflavone (ANF), a cytochrome P450 1A (CYP1A) inhibitor, affected the embryotoxicity of retene and the role that CYP1A inhibition may play in the interactions. Marine medaka (Oryzias melastigma) embryos were exposed, separately or together, to 200 μg/L retene with 0, 5, 10, 100, and 200 μg/L ANF for 14 days. The results showed that ANF significantly inhibited the induction of CYP1A activity by retene; however, ANF interacted with retene to induce significant developmental toxicity and genotoxicity at 10, 100, and 200 μg/L (p GST) activity and the alteration in metabolic profiles of retene were observed. The interactions of retene with ANF indicate that CYP1A inhibition was possibly act through different mechanisms to produce similar developmental effects and genotoxicity. Retene metabolites and altered metabolic profile were likely responsible for retene embryotoxicity to marine medaka. Therefore, elevated toxicity of alkyl-phenanthrene under CYP1A inhibitor suggested that the ecotoxicity of PAHs in coastal water may have underestimated the threat of PAHs to fish or ecosystem. PMID:26924701

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

    Science.gov (United States)

    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

  16. Oxidative Umpolung α‐Alkylation of Ketones

    DEFF Research Database (Denmark)

    Shneider, O. Svetlana; Pisarevsky, Evgeni; Fristrup, Peter; Szpilman, Alex M.

    2015-01-01

    We disclose a hypervalent iodine mediated α-alkylative umpolung reaction of carbonyl compounds with dialkylzinc as the alkyl source. The reaction is applicable to all common classes of ketones including 1,3-dicarbonyl compounds and regular ketones via their lithium enolates. The α-alkylated carbo......-alkylated carbonyl products are formed in up to 93% yield. An ionic mechanism is inferred based on meticulous analysis, NMR studies, trapping and crossover experiments, and computational studies.......We disclose a hypervalent iodine mediated α-alkylative umpolung reaction of carbonyl compounds with dialkylzinc as the alkyl source. The reaction is applicable to all common classes of ketones including 1,3-dicarbonyl compounds and regular ketones via their lithium enolates. The α...

  17. WITTIG REACTION APPROACH FOR THE SYNTHESIS OF 7-METHOXY-2-[4- ALKYL/ARYL]-L-BENZOFURAN-5-CARBOXALDEHYDE Wittig-Reaktion Ansatz für die Synthese von 7-Methoxy-2-[4 - ALKYL / ARYL]-L-BENZOFURAN-5-CARBOXALDEHYDE

    Directory of Open Access Journals (Sweden)

    Bapu R Thorata, Dyneshwar Shelke, Ramdas Atram and Ramesh Yamgar

    2013-07-01

    Full Text Available Vanillin undergoes sequence of reaction forming phosphonium salt through dimethyaminomethyl derivative (Mannich reaction. The synthesis of phosphonium salt can be achieved by sequence of three steps which was condense with series of aliphatic/aromatic acid chlorides by refluxing in toluene in presence of triethylamine (Wittig reaction as key step resulting 7-methoxy-2-alkyl/aryl-l-benzofuran-5-carboxaldehyde. The crude product was purified by using column chromatography and characterized by FTIR, NMR and Mass spectroscopy.

  18. Determining cysteine oxidation status using differential alkylation

    Science.gov (United States)

    Schilling, Birgit; Yoo, Chris B.; Collins, Christopher J.; Gibson, Bradford W.

    2004-08-01

    Oxidative damage to proteins plays a major role in aging and in the pathology of many degenerative diseases. Under conditions of oxidative stress, reactive oxygen and nitrogen species can modify key redox sensitive amino acid side chains leading to altered biological activities or structures of the targeted proteins. This in turn can affect signaling or regulatory control pathways as well as protein turnover and degradation efficiency in the proteasome. Cysteine residues are particularly susceptible to oxidation, primarily through reversible modifications (e.g., thiolation and nitrosylation), although irreversible oxidation can lead to products that cannot be repaired in vivo such as sulfonic acid. This report describes a strategy to determine the overall level of reversible cysteine oxidation using a stable isotope differential alkylation approach in combination with mass spectrometric analysis. This method employs 13C-labeled alkylating reagents, such as N-ethyl-[1,4-13C2]-maleimide, bromo-[1,2-13C2]-acetic acid and their non-labeled counterparts to quantitatively assess the level of cysteine oxidation at specific sites in oxidized proteins. The differential alkylation protocol was evaluated using standard peptides and proteins, and then applied to monitor and determine the level of oxidative damage induced by diamide, a mild oxidant. The formation and mass spectrometric analysis of irreversible cysteine acid modification will also be discussed as several such modifications have been identified in subunits of the mitochondrial electron transport chain complexes. This strategy will hopefully contribute to our understanding of the role that cysteine oxidation plays in such chronic diseases such as Parkinson's disease, where studies in animal and cell models have shown oxidative damage to mitochondrial Complex I to be a specific and early target.

  19. New Bioactive Alkyl Sulfates from Mediterranean Tunicates

    Directory of Open Access Journals (Sweden)

    Marialuisa Menna

    2012-10-01

    Full Text Available Chemical investigation of two species of marine ascidians, Aplidium elegans and Ciona edwardsii, collected in Mediterranean area, led to isolation of a series of alkyl sulfates (compounds 1–5 including three new molecules 1–3. Structures of the new metabolites have been elucidated by spectroscopic analysis. Based on previously reported cytotoxic activity of these type of molecules, compounds 1–3 have been tested for their effects on the growth of two cell lines, J774A.1 (BALB/c murine macrophages and C6 (rat glioma in vitro. Compounds 1 and 2 induced selective concentration-dependent mortality on J774A.1 cells.

  20. SYNTHESIS OF BIOLOGICALLY ACTIVE 2-CHLORO-N-ALKYL/ARYL ACETAMIDE DERIVATIVES

    Directory of Open Access Journals (Sweden)

    S.A.Katke

    2011-07-01

    Full Text Available Medicinal chemistry plays an important role in development of drug for cure; maintain and improved health of human being. It is also equally important to design chemical entities for prevent the growth of micro-organism, which come in contact with human being in day-to-day life. We have synthesized 2-chloro-N-alkyl/aryl Acetamide derivatives with an aim as new bioactive agent, which can be used as anti microbial agents such as herbicides, antifungal, disinfectant. The present study involves the synthesis, purification and characterization of various N-substituted chloroacetamide derivatives. The chloroacetyl chloride treated with various aliphatic and aromatic amines at room temperature with stirring for few hours with monitoring reaction by thin layer chromatography gave 2-chloro-N-alkyl/aryl Acetamide as solid compounds. We checked the melting point of synthesized compounds with an open ended capillary tube method. The spectral techniques like Infra red and GC-MS have been used for characterization and establishment of structure of synthesized compounds. The antimicrobial screening of the synthesized chloroacetamides have shown excellent antibacterial and antifungalactivity.

  1. Alkyl- and halogenophenols as synergistic agents in the solvent extraction of hafnium(IV)

    International Nuclear Information System (INIS)

    Several 2-alkyl-, 2,3-dialkyl-, and halogenophenols have been used as synergistic agents for the extraction of hafnium(IV) with N-benzoyl-N-phenyl hydroxylamine in toluene from 2M perchloric acid. The effect of the size and the position of the substituent on the aromatic ring is reported. The results are discussed from the point of view of various solute interactions. The distribution ratio of Hf(IV) was measured using the 175+18+H1Hf tracer, and is expressed as the organic-to-aqueous γ count rate ratio in the aliquots of the corresponding phases. The fact that 2-alkyl phenols are as efficient synergistic agents as the unsubstituted phenol is in agreement with the known fact that the substitution in 2-position does not produce any serious blocking of the hydroxyl group. o-Chlorophenol is the least effective synergistic agent of halogenophenols studied. This can be explained by the intramolecular hydrogen bonding in the synergist molecule similarly as in the case of nitrophenols. (T.I.)

  2. Polycyclic aromatic compounds in shale oils: influence of process conditions

    Energy Technology Data Exchange (ETDEWEB)

    Williams, P.T.; Nazzal, J.M. [University of Leeds (United Kingdom). Dept. of Fuel and Energy

    1998-08-01

    Polycyclic aromatic compounds (PAC) are a significant environmental chemical group, with an associated health hazard. They have been shown to be present in oils derived from the pyrolysis of oil shales; however, the influence of process conditions on their concentration is less well known. Oil shales were pyrolysed in a 200 cm{sup 3} stainless steel fixed bed reactor in relation to temperature from 400{sup o}C to 620{sup o}C in both a nitrogen and nitrogen/steam atmosphere. The condensed oils were analysed for their content of PAC, including polycyclic aromatic hydrocarbons (PAH), sulphur-PAH (PASH) and Nitrogen-PAH (PANH). The derived gases were analysed in terms of H{sub 2}, CO, CO{sub 2}, CH{sub 4} and other hydrocarbons to C{sub 4} and the alkene/alkane ratio determined. The derived shale oils were found to contain significant concentrations of PAH, PASH and PANH some of which have been shown to be biologically active. The main PAH were napthalene, fluorene and phenanthrene and their alkylated homologues; PASH identified included, benzothiophene, and dibenzothiophene and the PANH included indole, carbazole and quinoline and their alkylated derivatives. The concentration of PAC increased with increasing pyrolysis temperature and their formation was linked to increased secondary reactions as indicated by the gas phase alkene/alkane ratio. The influence of steam was to increase the yield of oil significantly. The presence of steam also increased the concentration of PAC in the derived shale oil compared to using nitrogen as the sweep gas. (author)

  3. Geochemical markers and polycyclic aromatic hydrocarbons in solvent extracts from diesel engine particulate matter.

    Science.gov (United States)

    Fabiańska, Monika; Kozielska, Barbara; Bielaczyc, Piotr; Woodburn, Joseph; Konieczyński, Jan

    2016-04-01

    Exhaust particulate from compression ignition (CI) engines running on engine and chassis dynamometers was studied. Particulate dichloromethane extracts were qualitatively and quantitatively analyzed for polycyclic aromatic hydrocarbons (PAHs) and biomarkers by gas chromatography with flame ionization detector (GC-FID) and gas chromatography-mass spectrometry (GC-MS). PAH group profiles were made and the PAH group shares according to the number of rings (2 or 3; 4; 5 or more) as well as diagnostic indices were calculated. Values of geochemical ratios of selected biomarkers and alkyl aromatic hydrocarbons were compared with literature values. A geochemical interpretation was carried out using these values and biomarker and alkyl aromatic hydrocarbon distributions. It has been shown that geochemical features are unequivocally connected to the emission of fossil fuels and biofuels burned in CI engines. The effect of the exothermic combustion process is limited to low-molecular-weight compounds, which shows that the applied methodology permits source identification of PAHs coexisting in the particulate emitted. PMID:26728284

  4. Current-voltage characteristics of a homologous series of polycyclic aromatic hydrocarbons.

    Science.gov (United States)

    Böhme, Thilo; Simpson, Christopher D; Müllen, Klaus; Rabe, Jürgen P

    2007-01-01

    A novel alkyl-substituted polycyclic aromatic hydrocarbon (PAH) with D(2h) symmetry and 78 carbon atoms in the aromatic core (C78) was synthesized, thereby completing a homologous series of soluble PAH compounds with increasing size of the aromatic pi system (42, 60, and 78 carbon atoms). The optical band gaps were determined by UV/Vis and fluorescence spectroscopy in solution. Scanning tunneling microscopy (STM) and spectroscopy (STS) revealed diode-like current versus voltage (I-V) characteristics through individual aromatic cores in monolayers at the interface between the solution and the basal plane of graphite. The asymmetry of the current-voltage (I-V) characteristics increases with the increasing size of the aromatic core, and the concomitantly decreasing HOMO-LUMO gap. This is attributed to resonant tunneling through the HOMO of the adsorbed molecule, and an asymmetric position of the molecular species in the tunnel junction. Consistently, submolecularly resolved STM images at negative substrate bias are in good agreement with the calculated pattern for the electron densities of the HOMOs. The analysis provides the basis for tailoring rectification with a single molecule in an STM junction. PMID:17579898

  5. Distribution and origin sources of Polycyclic Aromatic Hydrocarbons (PAHs) pollution in sediment of Sarawak coastal area

    International Nuclear Information System (INIS)

    Alkyl and parent Polycyclic Aromatic Hydrocarbons (PAHs) compounds in marine sediment sample collected from ten locations along Sarawak coastal areas were extracted and analyzed by using gas chromatography-mass spectrometry. The source identification of PAH pollution in marine sediment of Sarawak coastal areas were identify by ratios technique of An/ An+phen, Fl/ Fl +Py, B[a]A/ (B[a]A+Chry) and total Methyl Phen/ Phen. The total alkyl and parent PAHs concentration varies from 36.5 - 277.4 ng/ g dry weight (d.w.) with a mean concentration of 138.2 ng/ g d.w. The ratio values of PAHs pollution in marine sediment of Sarawak coastal areas are clearly indicating the PAHs pollutions are originated from petroleum (petrogenic) and petroleum combustion (pyrolytic). However, the origin sources of PAHs pollution in a few stations were uncertain due to mixing sources of PAHs. (author)

  6. Synthesis and structural characterisation of an yttrium-alkyl-alkylidene

    OpenAIRE

    Arnold, Polly; Green, J. C.; McMaster, J; Liddle, S.T.

    2008-01-01

    The first structurally authenticated yttrium-alkyl-alkylidene is reported; structural, spectroscopic, and theoretical analyses show that whilst the yttrium-alkylidene bond is short, it possesses a bond order less than one and is comparable to the Y-C-alkyl single bond within the same molecule.

  7. Polyfluorinated alkyl phosphate ester surfactants - current knowledge and knowledge gaps

    DEFF Research Database (Denmark)

    Taxvig, Camilla; Rosenmai, Anna Kjerstine; Vinggaard, Anne Marie

    2014-01-01

    information on fluorochemicals. Polyfluorinated alkyl phosphate ester surfactants (PAPs) belong to the group of polyfluorinated alkyl surfactants. They have been detected in indoor dust and are widely used in food-contact materials, from which they have the ability to migrate into food. Toxicological data on...

  8. 40 CFR 721.840 - Alkyl substituted diaromatic hydrocarbons.

    Science.gov (United States)

    2010-07-01

    ... hydrocarbons. 721.840 Section 721.840 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... Specific Chemical Substances § 721.840 Alkyl substituted diaromatic hydrocarbons. (a) Chemical substance... alkyl substituted di-aro-matic hydrocarbons (PMN P-91-710) is subject to reporting under this...

  9. Clinical applications of quinone-containing alkylating agents.

    Science.gov (United States)

    Begleiter, A

    2000-11-01

    Quinone-containing alkylating agents are a class of chemical agents that have received considerable interest as anticancer drugs. These agents contain a quinone moiety that can be reduced and an alkylating group that can form covalent bonds with a variety of cellular components. The oxidation state of the quinone element can modulate the activity of the alkylating element, and reduction of the quinone is required for activation of the alkylating activity of many of these agents. The quinone element may also contribute to the cytotoxic activity of quinone-containing alkylating agents through the formation of reactive oxygen species during redox cycling. The natural product, mitomycin C, has been the most widely used quinone-containing alkylating agent in the clinic, but other quinone-containing alkylating agents like porfiromycin, diaziquone, carbazilquinone, triaziquone and EO9 have also been used in the clinic for the treatment of cancer. In addition, many other quinone-containing alkylating agents have been tested in preclinical studies and the development of new agents is being actively pursued. This chapter describes the current and past clinical uses of these agents in the treatment of cancer and discusses new agents that are currently in clinical trials. PMID:11056078

  10. Degradable Polymer Composites Fabricated from Starch and Alkyl Cyanoacrylate Monomer

    Science.gov (United States)

    Degradable polymer composites are fabricated from alkyl cyanoacrylate monomer and starch without special equipment. Alkyl cyanoacrylate, which is a major component of “super glue”, is a monomer that polymerizes at room temperature in the presence of initiators. During the fabrication of polymer com...

  11. Toward Efficient Palladium-Catalyzed Allylic C-H Alkylation

    DEFF Research Database (Denmark)

    Jensen, Thomas; Fristrup, Peter

    2009-01-01

    Recent breakthroughs have proved that direct palladium (II)-catalyzed allylic C-H alkylation can be achieved. This new procedure shows that the inherent requirement for a leaving group in the Tsuji-Trost palladium-catalyzed allylic alkylation can be lifted. These initial reports hold great promise...

  12. β-Alkyl Elimination: Fundamental Principles and Some Applications.

    Science.gov (United States)

    O'Reilly, Matthew E; Dutta, Saikat; Veige, Adam S

    2016-07-27

    This review describes organometallic compounds and materials that are capable of mediating a rarely encountered but fundamentally important reaction: β-alkyl elimination at the metal-Cα-Cβ-R moiety, in which an alkyl group attached to the Cβ atom is transferred to the metal or to a coordinated substrate. The objectives of this review are to provide a cohesive fundamental understanding of β-alkyl-elimination reactions and to highlight its applications in olefin polymerization, alkane hydrogenolysis, depolymerization of branched polymers, ring-opening polymerization of cycloalkanes, and other useful organic reactions. To provide a coherent understanding of the β-alkyl elimination reaction, special attention is given to conditions and strategies used to facilitate β-alkyl-elimination/transfer events in metal-catalyzed olefin polymerization, which provide the well-studied examples. PMID:27366938

  13. Polybenzimidazoles Via Aromatic Nucleophilic Displacement

    Science.gov (United States)

    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.

  14. Bioassay of polycyclic aromatic hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    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.

  15. Micropropagation of different aromatic plants

    OpenAIRE

    Koleva Gudeva, Liljana; Iljovska Tusev, Jasmina; Trajkova, Fidanka

    2014-01-01

    Aromatic plants have been used for centuries as species, natural flavor, raw material for essential-oil industry and other purposes. Micropropagation has advantage over conventional propagation because of high multiplication rate, but it depends on the performance of the starting material, media composition, phytohormones and environmental factors. In this study, aromatic plants as peppermint (Menta piperita L.) and Menta sp., rosemary (Rosmarinus sp.), rocket (Eruca sativa Mill.), coriand...

  16. Benzo[b]naphthothiophenes and alkyl dibenzothiophenes: molecular tracers for oil migration distances

    Science.gov (United States)

    Li, Meijun; Wang, T.-G.; Shi, Shengbao; Liu, Keyu; Ellis, Geoffrey S.

    2014-01-01

    The secondary migration of petroleum is one of the most critical geological processes responsible for the accumulation of hydrocarbons in a sedimentary basin. Pyrrolic nitrogen compounds such as carbazoles and benzocarbazoles are thought to be practical molecular indicators for estimating relative migration distances of oil. In light oils or condensates, however, considerable analytical errors are usually caused by low concentrations of NSO-compounds. Here we show that polycyclic sulfur aromatic hydrocarbons such as dibenzothiophene, C1∼C3 alkylated dibenzothiophenes and benzo[b]naphthothiophenes, which are present in relatively higher concentrations than the pyrrolic nitrogen compounds, exhibit changes in both absolute and relative concentrations that correlate with migration distances. The polycyclic sulfur aromatic hydrocarbons related parameters — benzo[b]naphtho[2,1-d]thiophene/{benzo[b]naphtho[2,1-d]thiophene + benzo[b]naphtho[1,2-d]thiophene} (abbreviated as [2,1]BNT/([2,1]BNT+[1,2]BNT) and the concentration of total dibenzothiophenes plus benzo[b]naphthothiophenes — are proposed by this paper to trace the oil migration distances.

  17. Polar metabolites of polycyclic aromatic compounds from fungi are potential soil and groundwater contaminants

    DEFF Research Database (Denmark)

    Boll, Esther Sørensen; Johnsen, Anders R.; Christensen, Jan H.

    2015-01-01

    This study investigated the sorption to soil of water-soluble metabolites from polycyclic aromatic compounds (PACs). The soil fungus Cunninghamella elegans was used to produce PAC metabolites from two un-substituted PACs (phenanthrene, pyrene), three alkyl-substituted PACs (2-methylnaphthalene, 1...... calculated for fourteen representative metabolites. Sulfate conjugated metabolites displayed Kd's below 70 whereas the metabolites with both a sulfate and a carboxylic acid group had Kd's below 2.8. The low Kd's of water-soluble PAC metabolites indicate high mobility in soil and a potential for leaching to...

  18. Polycyclic Aromatic Hydrocarbons

    Science.gov (United States)

    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.

  19. Organomontmorillonites Modified with 2-Methacryloyloxy Ethyl Alkyl Dimethyl Ammonium Bromide

    Institute of Scientific and Technical Information of China (English)

    WANG Jian-quan; WU Wen-hui

    2007-01-01

    Organomontmorillonites (organo-MMT) were synthesized by means of montmorillonites (MMT) modified with a series of 2-methacryloyloxy ethyl alkyl dimethyl ammonium bromide (MAAB) having different alkyl chain lengths as cationic surfactants through a cationic exchanging reaction, and were characterized by FTIR, TG, elemental analysis, and XRD. The microenvironment of the organic interlayer such as the orientation and arrangement of the alkyl chains of MAAB, as well as the properties of nanocomposite hydrogels, were also investigated. The amount of organic components absorbed on interlayer and the basal spacing of organo-MMT both increase with the increasing of alkyl length of MAAB. When carbon number of alkyl chain is in the region of 8 to 14, the alkyl chains between layers would adopt a disordered gauche conformation; while the carbon number is 16, an ordered all-trans conformation with a vertical orientation would be found together with the disordered gauche conformation according to the results of XRD and FTIR. Due to the difference of microenvironment of organic interlayer, the Young's moduli of the nanocomposite hydrogels increased as the alkyl chains of MAAB became longer.

  20. Generation of a structurally diverse library through alkylation and ring closure reactions using 3-dimethylamino-1-(thiophen-2-yl)propan-1-one hydrochloride.

    Science.gov (United States)

    Roman, Gheorghe

    2013-01-01

    3-Dimethylamino-1-(thiophen-2-yl)propan-1-one hydrochloride (2), a ketonic Mannich base derived from 2-acetylthiophene, was used as a starting material in different types of alkylation and ring closure reactions with a view to generate a structurally diverse library of compounds. Compound 2 reacts with S-alkylated dithiocarbamic acid salts and aryl mercaptans to produce dithiocarbamates and thioethers, respectively. The dimethylamino moiety in compound 2 was exchanged with various aliphatic secondary and aromatic primary and secondary amines, whereas monocyclic NH-azoles such as pyrazole, imidazole, 1,2,4-triazole, and tetrazole were N-alkylated by compound 2. Ketones, pyrrole and indoles have been the substrates subjected to C-alkylation reactions by compound 2. Ring closure reactions of compound 2 with a suitable bifunctional nucleophile yielded pyrazolines, pyridines, 2,3-dihydro-1,5-1H-benzodiazepines, 2,3-dihydro-1,5-1H-benzothiazepine, pyrimido[1,2-a]benzimidazole and 4-hydroxypiperidine derivatives. PMID:23841334

  1. Comprehensive GC²/MS for the monitoring of aromatic tar oil constituents during biodegradation in a historically contaminated soil.

    Science.gov (United States)

    Vasilieva, Viktoriya; Scherr, Kerstin E; Edelmann, Eva; Hasinger, Marion; Loibner, Andreas P

    2012-02-20

    The constituents of tar oil comprise a wide range of physico-chemically heterogeneous pollutants of environmental concern. Besides the sixteen polycyclic aromatic hydrocarbons defined as priority pollutants by the US-EPA (EPA-PAHs), a wide range of substituted (NSO-PAC) and alkylated (alkyl-PAC) aromatic tar oil compounds are gaining increased attention for their toxic, carcinogenic, mutagenic and/or teratogenic properties. Investigations on tar oil biodegradation in soil are in part hampered by the absence of an efficient analytical tool for the simultaneous analysis of this wide range of compounds with dissimilar analytical properties. Therefore, the present study sets out to explore the applicability of comprehensive two-dimensional gas chromatography (GC²/MS) for the simultaneous measurement of compounds with differing polarity or that are co-eluting in one-dimensional systems. Aerobic tar oil biodegradation in a historically contaminated soil was analyzed over 56 days in lab-scale bioslurry tests. Forty-three aromatic compounds were identified with GC²/MS in one single analysis. The number of alkyl chains on a molecule was found to prime over alkyl chain length in hampering compound biodegradation. In most cases, substitution of carbon with nitrogen and oxygen was related to increased compound degradation in comparison to unalkylated and sulphur- or unsubstituted PAH with a similar ring number.The obtained results indicate that GC²/MS can be employed for the rapid assessment of a large variety of structurally heterogeneous environmental contaminants. Its application can contribute to facilitate site assessment, development and control of microbial cleanup technologies for tar oil contaminated sites. PMID:21924301

  2. Simple and Efficient Microwave Assisted N-Alkylation of Isatin

    Directory of Open Access Journals (Sweden)

    María Mercedes Blanco

    2008-04-01

    Full Text Available We present herein the results of microwave promoted N-alkylations of isatin (1with different alkyl, benzyl and functionalized alkyl halides. Reactions were carried outunder different conditions, always employing methodologies compatible with MW assistedchemistry. Generation of isatin anion employing diverse bases and solvents or using thepreformed isatin sodium salt was tested. The best results were achieved using K2CO3 orCs2CO3 and a few drops of N,N-dimethylformamide or N-methyl-2-pyrrolidinone. Thesereactions present noteworthy advantages over those carried out employing conventionalheating.

  3. Bacterial degradation of monocyclic aromatic amines

    Directory of Open Access Journals (Sweden)

    Pankaj Kumar Arora

    2015-08-01

    Full Text Available 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 compounds 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.

  4. Aromatic-Aromatic Interactions in Biological System: Structure Activity Relationships

    Energy Technology Data Exchange (ETDEWEB)

    Rajagopal, Appavu; Deepa, Mohan [Molecular Biophysics Unit, Indian Institute of Sciences-Bangalore, Karnataka (India); Govindaraju, Munisamy [Bio-Spatial Technology Research Unit, Department of Environmental Biotechnology, School of Environmental Sciences, Bharathidasan University, Tiruchirappalli, Tamil Nadu (India)

    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. Aromatic-Aromatic Interactions in Biological System: Structure Activity Relationships

    International Nuclear Information System (INIS)

    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”

  6. Aromatic-Aromatic Interactions in Biological System: Structure Activity Relationships

    Directory of Open Access Journals (Sweden)

    Rajagopal Appavu

    2016-03-01

    Full Text Available 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”.

  7. Synthesis and Biological evaluation of some of N-alkylidine/ Arylidene-5-Alkyl/Aryl - 1, 3, 4-Thiadiazol- 2 -Amines

    Directory of Open Access Journals (Sweden)

    Agarwal Alka

    2013-03-01

    Full Text Available A series N-Alkylidine/Arylidene-5- Alkyl/Aryl-1, 3, 4- Thiadiazol-2-Amines have been synthesized via multistep reaction sequence. The 5-alkyl/aryl-1, 3, 4-thiadiazol-2- amine derivatives were prepared by the reaction of different aliphatic/ aromatic carboxylic acids with thiosemicarbazide in presence of catalytic amount of concentrated sulfuric acid. These derivatives were treated with different aldehydes and ketones to afford the titled compounds. Structures of synthesized compounds were assigned on the basis analytical and spectral data. All the synthesized compounds were subjected to preliminary in-vitro antibacterial activity against Gram-positive bacterial strains Bacillus Subtillis and Gram-negative bacterial strains Klebsiella Pneumoniae, Escheria coli and Pseudomonas aeruginasa. The antifungal activity of the synthesized derivatives was evaluated against Candida albicans and Aspergillus fumigates. The synthesized compounds were found to possess comparable antimicrobial activity to the standard drug.

  8. Advances towards aromatic oligoamide foldamers

    DEFF Research Database (Denmark)

    Hjelmgaard, Thomas; Plesner, Malene; Dissing, Mette Marie; Andersen, Jeanette Marker; Frydenvang, Karla Andrea; Nielsen, John

    2014-01-01

    We have efficiently synthesized 36 arylopeptoid dimers with ortho-, meta-, and para-substituted aromatic backbones and tert-butyl or phenyl side chains. The dimers were synthesized by using a "submonomer method" on solid phase, by applying a simplified common set of reaction conditions. X......-ray crystallographic analysis of two of these dimers disclosed that the tert-butyl side chain invokes a cis amide conformation with a comparatively more closely packed structure of the surrounding aromatic backbone while the phenyl side chain results in a trans amide conformation with a more open, extended structure...... conformation with a more open, extended structure of the surrounding aromatic backbone. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim....

  9. Detection of Alkylating Agents using Electrical and Mechanical Means

    Energy Technology Data Exchange (ETDEWEB)

    Gerchikov, Yulia; Borzin, Elena; Gannot, Yair; Shemesh, Ariel; Meltzman, Shai; Hertzog-Ronen, Carmit; Eichen, Yoav [Schulich Department of Chemistry, Technion-Israel Institute of Technology, Technion City, 32000, Haifa (Israel) (Israel); Tal, Shay [Present address: Systems Biology Department, Harvard Medical School, Boston, MA 02115 (United States); Stolyarova, Sara; Nemirovsky, Yael; Tessler, Nir, E-mail: chryoav@tx.technion.ac.il [Department of Electrical Engineering, Technion-Israel Institute of Technology, Technion City, 32000, Haifa (Israel)

    2011-08-17

    Alkylating agents are reactive molecules having at least one polar bond between a carbon atom and a good leaving group. These often simple molecules are frequently used in organic synthesis, as sterilizing agents in agriculture and even as anticancer agents in medicine. Unfortunately, for over a century, some of the highly reactive alkylating agents are also being used as blister chemical warfare agents. Being relatively simple to make, the risk is that these will be applied by terrorists as poor people warfare agents. The detection and identification of such alkylating agents is not a simple task because of their high reactivity and simple structure of the reactive site. Here we report on new approaches to the detection and identification of such alkylating agents using electrical (organic field effect transistors) and mechanical (microcantilevers) means.

  10. Detection of Alkylating Agents using Electrical and Mechanical Means

    International Nuclear Information System (INIS)

    Alkylating agents are reactive molecules having at least one polar bond between a carbon atom and a good leaving group. These often simple molecules are frequently used in organic synthesis, as sterilizing agents in agriculture and even as anticancer agents in medicine. Unfortunately, for over a century, some of the highly reactive alkylating agents are also being used as blister chemical warfare agents. Being relatively simple to make, the risk is that these will be applied by terrorists as poor people warfare agents. The detection and identification of such alkylating agents is not a simple task because of their high reactivity and simple structure of the reactive site. Here we report on new approaches to the detection and identification of such alkylating agents using electrical (organic field effect transistors) and mechanical (microcantilevers) means.

  11. Copper-catalyzed arylation of alkyl halides with arylaluminum reagents

    Science.gov (United States)

    Shrestha, Bijay

    2015-01-01

    Summary We report a Cu-catalyzed coupling between triarylaluminum reagents and alkyl halides to form arylalkanes. The reaction proceeds in the presence of N,N,N’,N’-tetramethyl-o-phenylenediamine (NN-1) as a ligand in combination with CuI as a catalyst. This catalyst system enables the coupling of primary alkyl iodides and bromides with electron-neutral and electron-rich triarylaluminum reagents and affords the cross-coupled products in good to excellent yields. PMID:26734088

  12. Copper-catalyzed arylation of alkyl halides with arylaluminum reagents

    Directory of Open Access Journals (Sweden)

    Bijay Shrestha

    2015-12-01

    Full Text Available We report a Cu-catalyzed coupling between triarylaluminum reagents and alkyl halides to form arylalkanes. The reaction proceeds in the presence of N,N,N’,N’-tetramethyl-o-phenylenediamine (NN-1 as a ligand in combination with CuI as a catalyst. This catalyst system enables the coupling of primary alkyl iodides and bromides with electron-neutral and electron-rich triarylaluminum reagents and affords the cross-coupled products in good to excellent yields.

  13. Estrogenic Activity of Mineral Oil Aromatic Hydrocarbons Used in Printing Inks.

    Directory of Open Access Journals (Sweden)

    Patrick Tarnow

    Full Text Available The majority of printing inks are based on mineral oils (MOs which contain complex mixtures of saturated and aromatic hydrocarbons. Consumer exposure to these oils occurs either through direct skin contacts or, more frequently, as a result of MO migration into the contents of food packaging that was made from recycled newspaper. Despite this ubiquitous and frequent exposure little is known about the potential toxicological effects, particularly with regard to the aromatic MO fractions. From a toxicological point of view the huge amount of alkylated and unsubstituted compounds therein is reason for concern as they can harbor genotoxicants as well as potential endocrine disruptors. The aim of this study was to assess both the genotoxic and estrogenic potential of MOs used in printing inks. Mineral oils with various aromatic hydrocarbon contents were tested using a battery of in vitro assays selected to address various endpoints such as estrogen-dependent cell proliferation, activation of estrogen receptor α or transcriptional induction of estrogenic target genes. In addition, the comet assay has been applied to test for genotoxicity. Out of 15 MOs tested, 10 were found to potentially act as xenoestrogens. For most of the oils the effects were clearly triggered by constituents of the aromatic hydrocarbon fraction. From 5 oils tested in the comet assay, 2 showed slight genotoxicity. Altogether it appears that MOs used in printing inks are potential endocrine disruptors and should thus be assessed carefully to what extent they might contribute to the total estrogenic burden in humans.

  14. Estrogenic Activity of Mineral Oil Aromatic Hydrocarbons Used in Printing Inks

    Science.gov (United States)

    Tarnow, Patrick; Hutzler, Christoph; Grabiger, Stefan; Schön, Karsten; Tralau, Tewes; Luch, Andreas

    2016-01-01

    The majority of printing inks are based on mineral oils (MOs) which contain complex mixtures of saturated and aromatic hydrocarbons. Consumer exposure to these oils occurs either through direct skin contacts or, more frequently, as a result of MO migration into the contents of food packaging that was made from recycled newspaper. Despite this ubiquitous and frequent exposure little is known about the potential toxicological effects, particularly with regard to the aromatic MO fractions. From a toxicological point of view the huge amount of alkylated and unsubstituted compounds therein is reason for concern as they can harbor genotoxicants as well as potential endocrine disruptors. The aim of this study was to assess both the genotoxic and estrogenic potential of MOs used in printing inks. Mineral oils with various aromatic hydrocarbon contents were tested using a battery of in vitro assays selected to address various endpoints such as estrogen-dependent cell proliferation, activation of estrogen receptor α or transcriptional induction of estrogenic target genes. In addition, the comet assay has been applied to test for genotoxicity. Out of 15 MOs tested, 10 were found to potentially act as xenoestrogens. For most of the oils the effects were clearly triggered by constituents of the aromatic hydrocarbon fraction. From 5 oils tested in the comet assay, 2 showed slight genotoxicity. Altogether it appears that MOs used in printing inks are potential endocrine disruptors and should thus be assessed carefully to what extent they might contribute to the total estrogenic burden in humans. PMID:26771904

  15. Alkyl-halogenide promoted ionic liquid catalysis of isobutane/butene-alkylation

    Energy Technology Data Exchange (ETDEWEB)

    Schilder, L.; Korth, W.; Jess, A. [Bayreuth Univ. (Germany). Dept. of Chemical Engineering

    2011-07-01

    The effect of two different types of promoters on the performance of Lewis-acidic chloroaluminate ionic liquid catalysts was studied for liquid liquid biphasic isobutane/2-butene alkylation. In particular, the activity and selectivity of such catalytic systems was investigated. Experimental results obtained from a batch reactor show, that tert-butyl halides increase the reaction rate significantly and shift the C8-selectivity towards the desired high-octane trimethylpentanes (TMPs). But, secondary reactions like oligomerization and cracking are not affected by the use of these promoters. (orig.)

  16. Alcohols as alkylating agents in heteroarene C-H functionalization

    Science.gov (United States)

    Jin, Jian; MacMillan, David W. C.

    2015-09-01

    Redox processes and radical intermediates are found in many biochemical processes, including deoxyribonucleotide synthesis and oxidative DNA damage. One of the core principles underlying DNA biosynthesis is the radical-mediated elimination of H2O to deoxygenate ribonucleotides, an example of `spin-centre shift', during which an alcohol C-O bond is cleaved, resulting in a carbon-centred radical intermediate. Although spin-centre shift is a well-understood biochemical process, it is underused by the synthetic organic chemistry community. We wondered whether it would be possible to take advantage of this naturally occurring process to accomplish mild, non-traditional alkylation reactions using alcohols as radical precursors. Because conventional radical-based alkylation methods require the use of stoichiometric oxidants, increased temperatures or peroxides, a mild protocol using simple and abundant alkylating agents would have considerable use in the synthesis of diversely functionalized pharmacophores. Here we describe the development of a dual catalytic alkylation of heteroarenes, using alcohols as mild alkylating reagents. This method represents the first, to our knowledge, broadly applicable use of unactivated alcohols as latent alkylating reagents, achieved via the successful merger of photoredox and hydrogen atom transfer catalysis. The value of this multi-catalytic protocol has been demonstrated through the late-stage functionalization of the medicinal agents, fasudil and milrinone.

  17. Final Technical Report [Development of Catalytic Alkylation and Fluoroalkylation Methods

    Energy Technology Data Exchange (ETDEWEB)

    Vicic, David A.

    2014-05-01

    In the early stages of this DOE-funded research project, we sought to prepare and study a well-defined nickel-alkyl complex containing tridentate nitrogen donor ligands. We found that reaction of (TMEDA)NiMe2 (1) with terpyridine ligand cleanly led to the formation of (terpyridyl)NiMe (2), which we also determined to be an active alkylation catalyst. The thermal stability of 2 was unlike that seen for any of the active pybox ligands, and enabled a number of key studies on alkyl transfer reactions to be performed, providing new insights into the mechanism of nickel-mediated alkyl-alkyl cross-coupling reactions. In addition to the mechanistic studies, we showed that the terpyridyl nickel compounds can catalytically cross-couple alkyl iodides in yields up to 98% and bromides in yields up to 46 %. The yields for the bromides can be increased up to 67 % when the new palladium catalyst [(tpy’)Pd-Ph]I is used. The best route to the targeted [(tpy)NiBr] (1) was found to involve the comproportionation reaction of [(dme)NiBr{sub 2}] and [Ni(COD){sub 2}] in the presence of two equivalents of terpyridine. This reaction was driven to high yields of product formation (72 % isolated) by the precipitation of 1 from THF solvent.

  18. FTIR SPECTRA OF ADSORBED PYRIDINE OVER HIGH SILICA USY ,TI-USY AND FE-TI-USY ZEOLITE AND ALKYLATION OF O-TOLUIDINE OVER THEM.

    Directory of Open Access Journals (Sweden)

    K.U.GORE

    2013-05-01

    Full Text Available Alkylated aromatic amines are industrially very important. Ortho alkylatedamines are used as intermedites for producing dyes , insecticides, resins ,Stabilizers,rubber processing chemicals and as a liquid fuel in missiles. The usefulnessof the zeolite due to its modified stural changes can be tested by studing the change inits role as a catylist in carrying out the chemical reactions as compared to its originalsample. zeolite- Y due to its 3D pore structure is the single largest Zeolite used indifferent industries even today. zeolites are stabilized at higher temperature and inhydrothermal condition to increase its stability and usefulness under various reactionconditions.

  19. An active site aromatic triad in Escherichia coli DNA Pol IV coordinates cell survival and mutagenesis in different DNA damaging agents.

    Directory of Open Access Journals (Sweden)

    Ryan W Benson

    Full Text Available DinB (DNA Pol IV is a translesion (TLS DNA polymerase, which inserts a nucleotide opposite an otherwise replication-stalling N(2-dG lesion in vitro, and confers resistance to nitrofurazone (NFZ, a compound that forms these lesions in vivo. DinB is also known to be part of the cellular response to alkylation DNA damage. Yet it is not known if DinB active site residues, in addition to aminoacids involved in DNA synthesis, are critical in alkylation lesion bypass. It is also unclear which active site aminoacids, if any, might modulate DinB's bypass fidelity of distinct lesions. Here we report that along with the classical catalytic residues, an active site "aromatic triad", namely residues F12, F13, and Y79, is critical for cell survival in the presence of the alkylating agent methyl methanesulfonate (MMS. Strains expressing dinB alleles with single point mutations in the aromatic triad survive poorly in MMS. Remarkably, these strains show fewer MMS- than NFZ-induced mutants, suggesting that the aromatic triad, in addition to its role in TLS, modulates DinB's accuracy in bypassing distinct lesions. The high bypass fidelity of prevalent alkylation lesions is evident even when the DinB active site performs error-prone NFZ-induced lesion bypass. The analyses carried out with the active site aromatic triad suggest that the DinB active site residues are poised to proficiently bypass distinctive DNA lesions, yet they are also malleable so that the accuracy of the bypass is lesion-dependent.

  20. Survey of Recent Innovations in Aromatic Rice

    OpenAIRE

    Napasintuwong, Orachos

    2012-01-01

    This paper provides situations of aromatic rice demand, and international standards. The history and recent developments of traditional and evolved aromatic rice varieties, namely Basmati rice and Jasmine rice, are reviewed. The emerging aromatic rice innovations from developed countries such as the U.S. and other Asian countries generate a threat to these traditional aromatic rice producers such as India, Pakistan, and Thailand. Under WTO Trade Related Aspects of Intellectual Property Rights...

  1. Polycyclic aromatic compounds in oils derived from the fluidised bed pyrolysis of oil shale

    Energy Technology Data Exchange (ETDEWEB)

    Williams, Paul T.; Nazzal, Jamal M. [Department of Fuel and Energy, The University of Leeds, Leeds (United Kingdom)

    1995-12-01

    Oil shale was pyrolysed in a 10 cm diameterx100 cm high fluidised bed reactor with nitrogen as the fluidising gas at pyrolysis temperatures of 400, 450, 520, 570 and 620C. The gases were analysed by packed column gas chromatography. The condensed pyrolytic oils were analysed for their content of polycyclic aromatic compounds (PAC), including polycyclic aromatic hydrocarbons (PAH), sulphur-PAH (PASH) and nitrogen-PAH (PANH). The oils were fractionated into chemical classes using mini-column liquid chromatography followed by analysis using capillary column gas chromatography with flame ionisation detection (GC/FID) and capillary column GC with mass spectrometry (GC/MS) for identification and quantification of PAH. PASH and PANH were identified in the chemical class fractions using capillary column GC with selective detection and GC/MS. The pyrolytic shale oils were found to contain significant concentrations of PAH, PASH and PANH. The concentrations of PAC were increased with increasing reactor temperature and residence time. The PAH consisted mainly of naphthalene, fluorene and phenanthrene and their alkylated homologues, and lower concentrations of fluoranthene, pyrene and chrysene. The PASH identified included benzothiophene, and dibenzothiophene, and the PANH identified including indole and carbazole and their alkylated derivatives. Some of the PAC identified have been reported to be mutagenic and/or carcinogenic

  2. Depolymerization of coal by oxidation and alkylation; Sanka bunkai to alkyl ka ni yoru sekitan kaijugo

    Energy Technology Data Exchange (ETDEWEB)

    Tomita, H.; Isoda, T.; Kusakabe, K.; Morooka, S. [Kyushu University, Fukuoka (Japan). Faculty of Engineering; Hayashi, J. [Hokkaido University, Sapporo (Japan). Center for Advanced Research of Energy Technology

    1996-10-28

    Change in depolymerization degree and coal structure was studied for depolymerization treatment of coal in various alcohol containing aqueous hydrogen peroxide. In experiment, the mixture of Yallourn coal, alcohol and aqueous hydrogen peroxide was agitated in nitrogen atmosphere of normal pressure at 70{degree}C for 12 hours. As the experimental result, the methanol solubility of only 5% of raw coal increased up to 35.2% by hydrogen peroxide treatment, while the yield of insoluble matters also decreased from 94% to 62%. Most of the gas produced during treatment was composed of inorganic gases such as CO and CO2, and its carbon loss was extremely decreased by adding alcohol. From the analytical result of carbon loss in hydrogen peroxide treatment, it was clarified that alkylation advances with introduction of alkyl group derived from alcohol into coal by hydrogen peroxide treatment under a coexistence of alcohol, and depolymerization reaction of coal itself is thus promoted by alcohol. 4 refs., 7 figs., 1 tab.

  3. Selective inhibition of human inducible nitric oxide synthase by S-alkyl-L-isothiocitrulline-containing dipeptides.

    Science.gov (United States)

    Park, J M; Higuchi, T; Kikuchi, K; Urano, Y; Hori, H; Nishino, T; Aoki, J; Inoue, K; Nagano, T

    2001-04-01

    The aim of this study was to investigate the structure-activity relationship of S-alkyl-L-isothiocitrulline-containing dipeptides towards three partially purified recombinant human nitric oxide synthase (NOS) isozymes, as well as the effects of these compounds on cytokine-induced NO production by human DLD-1 cells. In an in vitro assay, S-methyl-L-isothiocitrulline (L-MIT) was slightly selective for human neuronal NOS (nNOS) over the inducible (iNOS) or endothelial (eNOS) isozyme, but the combination of a hydrophobic L-amino acid (L-Phe, L-Leu or L-Trp) with L-MIT dramatically altered the inhibition pattern to give selective iNOS inhibitors. Introduction of a hydroxy, nitro, amino or methoxy group at the para position of the aromatic ring of L-MIT-L-Phe (MILF) decreased the selectivity and inhibitory potency. A longer or larger S-alkyl group also decreased the selectivity and potency. Dixon analysis showed that all of the dipeptides were competitive inhibitors of the three isoforms of human NOS. The enzymatic time course curves indicated that MILF was a slow binding inhibitor of human iNOS. These results suggest that the human NOS isozymes have different-sized cavities in the binding site near the position to which the C-terminal of L-arginine binds, and the cavity of iNOS is hydrophobic. Interestingly, L-MIT-D-Phe (MIDF) showed little inhibitory activity or selectivity, suggesting that the cavity of human iNOS is located in a well-defined direction from the alpha carbon atom. NO production in cytokine-stimulated human DLD-1 cells was measured with a fluorescent indicator, DAF-FM. MILF, L-MIT-L-Trp(-CHO) (MILW) and L-MIT-L-Tyr (MILY) showed more potent activity than L-MIT in this whole-cell assay. Thus, S-alkyl-L-isothiocitrulline-containing dipeptides are selective inhibitors of human iNOS, and work efficiently in cell-based assay. PMID:11309260

  4. Solubility of gases in 1-alkyl-3methylimidazolium alkyl sulfate ionic liquids: Experimental determination and modeling

    International Nuclear Information System (INIS)

    Highlights: ► The solubility of CO2, CH4 and C2H6 in [emim][EtSO4] is measured with a magnetic suspension balance. ► New data and literature results have been modeled with a Group Contribution equation of state. ► A specific group definition is required to model data of ionic liquids with a [MeSO4] anion. ► Deviations between model and experiments are lower than 10% in most cases. ► Deviations of 34% are observed in the case of the solubility of ethane in the ionic liquid. -- Abstract: The solubility of different gases (carbon dioxide, methane, ethane, carbon monoxide and hydrogen) in ionic liquids with an alkyl sulfate anion has been modeled with the Group Contribution equation of state developed by Skjold-Jørgensen. New gas solubility measurements have been carried out with a high pressure magnetic suspension balance in order to cover pressure and temperature ranges not considered in previous studies and to obtain more experimental information for the correlation of parameters of the equation of state. New solubility measurements include the solubility of carbon dioxide in 1-ethyl 3-methyl imidazolium ethyl sulfate [emim][EtSO4] at temperatures of 298 K and 348 K and pressures ranging from 0.3 MPa to 6.5 MPa, the solubility of methane in [emim][EtSO4] at a temperature of 293 K and pressures ranging from 0.2 MPa to 10.2 MPa, and the solubility of ethane in [emim][EtSO4] at temperatures of 323 K and 350 K and pressures ranging from 0.2 MPa to 4 MPa. Results show that the Group Contribution equation of state can be used to describe the solubility of gases in alkyl sulfate ionic liquids as well as infinite dilution coefficients of alkanes in the ionic liquids, with average deviations between experiments and calculations ranging from 1% to 10% in the case of mixtures with CO2, CO, CH4 and H2 with the alkyl sulfate ionic liquids to up to 34% in the case of the solubility of ethane in [emim][EtSO4

  5. Effect of the Structure of Cations and Anions of Ionic Liquids on Separation of Aromatics from Hydrocarbon Mixtures

    Institute of Scientific and Technical Information of China (English)

    Liu Yansheng; Zhang Zhongxin; Zhang Guofu; Liu Zhichang; Hu Yufeng; Shi Quan; Ji Dejun

    2006-01-01

    The effects of the structure of typical cations and anions of ionic liquids on the separation of benzene and toluene from aromatic/paraffin mixtures were studied. The results showed that the corresponding separation factors were considerably larger than those of the traditional solvents (Benzene+Hexane+sulfolane), and that the ionic liquids could be used as novel solvents for the separation of aromatics from hydrocarbon mixtures. The key parameters governing the ability of ionic liquids for separating aromatics from hydrocarbon sources were investigated. It was found that the effectiveness of the ionic liquids, based on the same anion, changed in the cation order of [BIqu]+< [BPy]+< [BMIM]+. The selectivity of the ionic liquid toward aromatics decreased apparently with the increasing length of the substituted alkyl chain of its cationic head ring. The separation factors, based on the same cation, changed in the anion order of [Tf2N]-<[PF6]-<[BF4]-<[C2H5SO4]-. The solubilities of the aromatics were greater in the ionic liquids based on the former three anions than that in the ionic liquids involving [C2H5SO4]-.

  6. A DFT-based toxicity QSAR study of aromatic hydrocarbons to Vibrio fischeri: Consideration of aqueous freely dissolved concentration.

    Science.gov (United States)

    Wang, Ying; Yang, Xianhai; Wang, Juying; Cong, Yi; Mu, Jingli; Jin, Fei

    2016-05-01

    In the present study, quantitative structure-activity relationship (QSAR) techniques based on toxicity mechanism and density functional theory (DFT) descriptors were adopted to develop predictive models for the toxicity of alkylated and parent aromatic hydrocarbons to Vibrio fischeri. The acute toxicity data of 17 aromatic hydrocarbons from both literature and our experimental results were used to construct QSAR models by partial least squares (PLS) analysis. With consideration of the toxicity process, the partition of aromatic hydrocarbons between water phase and lipid phase and their interaction with the target biomolecule, the optimal QSAR model was obtained by introducing aqueous freely dissolved concentration. The high statistical values of R(2) (0.956) and Q(CUM)(2) (0.942) indicated that the model has good goodness-of-fit, robustness and internal predictive power. The average molecular polarizability (α) and several selected thermodynamic parameters reflecting the intermolecular interactions played important roles in the partition of aromatic hydrocarbons between the water phase and biomembrane. Energy of the highest occupied molecular orbital (E(HOMO)) was the most influential descriptor which dominated the toxicity of aromatic hydrocarbons through the electron-transfer reaction with biomolecules. The results demonstrated that the adoption of freely dissolved concentration instead of nominal concentration was a beneficial attempt for toxicity QSAR modeling of hydrophobic organic chemicals. PMID:26812082

  7. Sources of polycyclic aromatic hydrocarbons (PAHs) pollution in marine sediment from Tuanku Abdul Rahman National Park, Sabah

    International Nuclear Information System (INIS)

    The concentrations of parent and alkyl Polycyclic Aromatic Hydrocarbons (PAHs) in marine sediment samples collected from Tuanku Abdul Rahman National Park, Sabah were determined by using GC-MS. The ratio of anthracene to anthracene plus phenanthrene, fluoranthene to fluoranthene plus pyrene, benz[a]anthracene to benz[a]anthracene plus chrysene and indeno[1,2,3-cd]pyrene to indeno[1,2,3-cd]pyrene plus benzo[g,h,i]perylene, compounds were used to identify the sources of PAHs pollution. The total concentration of parent and alkyl PAHs are ranged from 121.7 to 191.5 ng/ g dry weight. The concentrations of PAHs pollution in sediments were categorised as a moderate polluted. The ratio values of PAHs compound indicate the origin source of PAHs pollutions in marine sediment sample of Tuanku Abdul Rahman National Park were originated from fossil fuel combustion (pyrolytic). (author)

  8. N-Alkyl-, 1-C-Alkyl-, and 5-C-Alkyl-1,5-dideoxy-1,5-imino-(L)-ribitols as Galactosidase Inhibitors.

    Science.gov (United States)

    Front, Sophie; Gallienne, Estelle; Charollais-Thoenig, Julie; Demotz, Stéphane; Martin, Olivier R

    2016-01-01

    A series of 1,5-dideoxy-1,5-imino-(l)-ribitol (DIR) derivatives carrying alkyl or functionalized alkyl groups were prepared and investigated as glycosidase inhibitors. These compounds were designed as simplified 4-epi-isofagomine (4-epi-IFG) mimics and were expected to behave as selective inhibitors of β-galactosidases. All compounds were indeed found to be highly selective for β-galactosidases versus α-glycosidases, as they generally did not inhibit coffee bean α-galactosidase or other α-glycosidases. Some compounds were also found to be inhibitors of almond β-glucosidase. The N-alkyl DIR derivatives were only modest inhibitors of bovine β-galactosidase, with IC50 values in the 30-700 μM range. Likewise, imino-L-ribitol substituted at the C1 position was found to be a weak inhibitor of this enzyme. In contrast, alkyl substitution at C5 resulted in enhanced β-galactosidase inhibitory activity by a factor of up to 1000, with at least six carbon atoms in the alkyl substituent. Remarkably, the 'pseudo-anomeric' configuration in this series does not appear to play a role. Human lysosomal β-galactosidase from leukocyte lysate was, however, poorly inhibited by all iminoribitol derivatives tested (IC50 values in the 100 μM range), while 4-epi-IFG was a good inhibitor of this enzyme. Two compounds were evaluated as pharmacological chaperones for a GM1-gangliosidosis cell line (R301Q mutation) and were found to enhance the mutant enzyme activity by factors up to 2.7-fold. PMID:26644389

  9. 烷基芳基磺酸钠对烷烃的乳化性能%Emulsifing Properties of Sodium Alkyl Aryl Sulfonate to Alkanes

    Institute of Scientific and Technical Information of China (English)

    于涛; 刘华沙; 王超群; 丁伟; 曲广淼

    2011-01-01

    采用分水时间法考察了结构明确的高纯度烷基芳基磺酸钠在烷烃中的乳化现象.以液态石蜡为油相,讨论了乳化剂浓度对乳状液稳定性的影响,确定了最适宜的乳化剂浓度,并研究了烷基链长度、芳基结构和芳基在烷基链位置对形成的乳状液稳定性的影响关系,考察了不同油相对乳状液稳定性的影响.结果表明,最适宜的乳化剂质量分数为0.1%;当固定芳基结构时,随着烷基链上碳数的增加,乳状液稳定性线性增强;当固定烷基链碳数时,随着芳基仁碳原子的增加,乳状液稳定性增强;随着芳基位置向烷基链中间位置移动,乳状液稳定性增强;随着油相分子量的增加,能形成稳定乳状液所需的乳化剂的分子量随之递增.%The abilities of sodium alkyl aryl sulfonate, which had high-purity and defined structure, to emulsify alkanes, were investigated by a water diversion method. Using liquid paraffin wax as the oil phase, the effects of the concentration of emulsion, length of alkyl chain, structures and locations of aryl groups in alkyl chain on emulsion stability were studied, and the best concentration of emulsion were determined. Meanwhile, the effects of different oil phases to emulsion stability were discussed. The experimental data showed that the best mass fraction of emulsion was 0. 1 %. With definite structures of aryl group, emulsion stability increased linearly with the increasing of the length of carbonic chain. When the length of alkyl chain on alkyl group was set, the emulsion stability was enhanced with the increasing of the length of alkyl chain on aryl group. With the aromatic ring shifts from the terminal to the center of the long alkyl chain, the emulsion stability increased. With the increase of molecular mass of oil phases, the molecular mass of emulsifier to achieve stable emulsifying liquid increased.

  10. Nucleophilic fluorination of aromatic compounds

    Energy Technology Data Exchange (ETDEWEB)

    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.

  11. Alkyl substituent effect on density, viscosity and chemical behavior of 1-alkyl-3-methylimidazolium chloride.

    Science.gov (United States)

    Olmo, Lourdes del; Lage-Estebanez, Isabel; López, Rafael; García de la Vega, José M

    2014-09-01

    Molecular structure of the conformers of 1-C n -3-methylimidazolium chloride (n = 1 to 4) ionic liquids has been explored and the relationships with density and viscosity have been studied using COSMO related methodologies. Effects of the number of conformers, ionic character, anion-cation relative positions and the alkyl chain length of the cation on predictions of properties have been analyzed. The quality of the predictions has been tested by comparing with experimental results. Moreover, COSMO polarization charge densities, σ-profiles and σ-potentials of the conformers have been analyzed. Predictions on the chemical behavior based on the values of these properties in the conformers have been used to elucidate the affinity for electrophilic and nucleophilic reagents of ionic liquids. PMID:25149437

  12. Biodegradation of Polycyclic Aromatic Hydrocarbons

    OpenAIRE

    DEMİR, İsmail; DEMİRBAĞ, Zihni

    1999-01-01

    Polycylic aromatic hydrocarbons (PAHs), such as petroleum and petroleum derivatives, are widespread organic pollutants entering the environment, chiefly, through oil spills and incomplete combustion of fossil fuels. Since most PAHs are persist in the environment for a long period of time and bioaccumulate, they cause environmental pollution and effect biological equilibrium dramatically. Biodegradation of some PAHs by microorganisms has been biochemically and genetically investigated. Ge...

  13. Analysis of heterocyclic aromatic amines.

    Science.gov (United States)

    Murkovic, M

    2007-09-01

    Heterocyclic aromatic amines are formed in protein and amino acid-rich foods at temperatures above 150 degrees C. Of more than twenty heterocyclic aromatic amines identified ten have been shown to have carcinogenic potential. As nutritional hazards, their reliable determination in prepared food, their uptake and elimination in living organisms, including humans, and assessment of associated risks are important food-safety issues. The concentration in foods is normally in the low ng g(-1) range, which poses a challenge to the analytical chemist. Because of the complex nature of food matrixes, clean-up and enrichment of the extracts are also complex, usually involving both cation-exchange (propylsulfonic acid silica gel, PRS) and reversed-phase purification. The application of novel solid-phase extraction cartridges with a wettable apolar phase combined with cation-exchange characteristics simplified this process--both the polar and apolar heterocyclic aromatic amines were recovered in one fraction. Copper phthalocyanine trisulfonate bonded to cotton ("blue cotton") or rayon, and molecular imprinted polymers have also been successfully used for one-step sample clean-up. For analysis of the heterocyclic aromatic amines, liquid chromatography with base-deactivated reversed-phase columns has been used, and, recently, semi-micro and capillary columns have been introduced. The photometric, fluorimetric, or electrochemical detectors used previously have been replaced by mass spectrometers. Increased specificity and sub-ppb sensitivities have been achieved by the use of the selected-reaction-monitoring mode of detection of advanced MS instrumentation, for example the triple quadrupole and Q-TOF instrument combination. Gas chromatography, also with mass-selective detection, has been used for specific applications; the extra derivatization step needed for volatilization has been balanced by the higher chromatographic resolution. PMID:17546447

  14. Deuterated polycyclic aromatic hydrocarbons: Revisited

    CERN Document Server

    Doney, Kirstin D; Mori, Tamami; Onaka, Takashi; Tielens, A G G M

    2016-01-01

    The amount of deuterium locked up in polycyclic aromatic hydrocarbons (PAHs) has to date been an uncertain value. We present a near-infrared (NIR) spectroscopic survey of HII regions in the Milky Way, Large Magellanic Cloud (LMC), and Small Magellanic Cloud (SMC) obtained with AKARI, which aims to search for features indicative of deuterated PAHs (PAD or Dn-PAH) to better constrain the D/H ratio of PAHs. Fifty-three HII regions were observed in the NIR (2.5-5 {\\mu}m), using the Infrared Camera (IRC) on board the AKARI satellite. Through comparison of the observed spectra with a theoretical model of deuterated PAH vibrational modes, the aromatic and (a)symmetric aliphatic C-D stretch modes were identified. We see emission features between 4.4-4.8 {\\mu}m, which could be unambiguously attributed to deuterated PAHs in only six of the observed sources, all of which are located in the Milky Way. In all cases, the aromatic C-D stretching feature is weaker than the aliphatic C-D stretching feature, and, in the case o...

  15. The direct aromatization of methane

    Energy Technology Data Exchange (ETDEWEB)

    Marcelin, G.; Oukaci, R.; Migone, R.A.; Kazi, A.M. [Altamira Instruments, Pittsburgh, PA (United States)

    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.

  16. Alkylation of imidazole under ultrasound irradiation over alkaline carbons

    International Nuclear Information System (INIS)

    N-Alkyl-imidazole has been synthesized by sonochemical irradiation of imidazole and 1-bromobutane using alkaline-promoted carbons (exchanged with the binary combinations of Na, K and Cs). The catalysts were characterized by X-ray photoelectron spectroscopy, thermal analysis and N2 adsorption isotherms. Under the experimental conditions, N-alkyl-imidazoles can be prepared with a high activity and selectivity. It is observed that imidazole conversion increases in parallel with increasing the basicity of the catalyst. The influence of the alkaline promoter, the reaction temperature, and the amount of catalyst on the catalytic activity has been studied. For comparison, the alkylation of imidazole has also been performed in a batch reactor system under thermal activation

  17. Alkyl Radicals as Hydrogen Bond Acceptors: Computational Evidence

    DEFF Research Database (Denmark)

    Hammerum, Steen

    2009-01-01

    Spectroscopic, energetic and structural information obtained by DFT and G3-type computational studies demonstrates that charged proton donors can form moderately strong hydrogen bonds to simple alkyl radicals. The presence of these bonds stabilizes the adducts and modifies their structure, and...... gives rise to pronounced shifts of IR stretching frequencies and to increased absorption intensities. The hydrogen bond acceptor properties of alkyl radicals equal those of many conventional acceptors, e.g., the bond length changes and IR red-shifts suggest that tert-butyl radicals are slightly better...... acceptors than formaldehyde molecules, while propyl radicals are as good as H2O. The hydrogen bond strength appears to depend on the proton affinity of the proton donor and on the ionization energy of the acceptor alkyl radical, not on the donor-acceptor proton affinity difference, reflecting that the...

  18. Alkylation of imidazole under ultrasound irradiation over alkaline carbons

    Energy Technology Data Exchange (ETDEWEB)

    Costarrosa, L. [Dpto. de Quimica Inorganica y Quimica Tecnica, Facultad de Ciencias, Universidad Nacional de Educacion a Distancia (UNED), C/Senda del Rey, 9, E-28040 Madrid (Spain); Calvino-Casilda, V. [Dpto. de Quimica Inorganica y Quimica Tecnica, Facultad de Ciencias, Universidad Nacional de Educacion a Distancia (UNED), C/Senda del Rey, 9, E-28040 Madrid (Spain); Ferrera-Escudero, S. [Dpto. de Quimica Inorganica y Quimica Tecnica, Facultad de Ciencias, Universidad Nacional de Educacion a Distancia (UNED), C/Senda del Rey, 9, E-28040 Madrid (Spain); Duran-Valle, C.J. [Dpto. de Quimica Inorganica, Facultad de Ciencias, Universidad de Extremadura, Avenida de Elvas s/n, 06071 Badajoz (Spain); Martin-Aranda, R.M. [Dpto. de Quimica Inorganica y Quimica Tecnica, Facultad de Ciencias, Universidad Nacional de Educacion a Distancia (UNED), C/Senda del Rey, 9, E-28040 Madrid (Spain)]. E-mail: rmartin@ccia.uned.es

    2006-06-30

    N-Alkyl-imidazole has been synthesized by sonochemical irradiation of imidazole and 1-bromobutane using alkaline-promoted carbons (exchanged with the binary combinations of Na, K and Cs). The catalysts were characterized by X-ray photoelectron spectroscopy, thermal analysis and N{sub 2} adsorption isotherms. Under the experimental conditions, N-alkyl-imidazoles can be prepared with a high activity and selectivity. It is observed that imidazole conversion increases in parallel with increasing the basicity of the catalyst. The influence of the alkaline promoter, the reaction temperature, and the amount of catalyst on the catalytic activity has been studied. For comparison, the alkylation of imidazole has also been performed in a batch reactor system under thermal activation.

  19. Safety Assessment of Alkyl Ethylhexanoates as Used in Cosmetics.

    Science.gov (United States)

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

    2015-01-01

    The Cosmetic Ingredient Review (CIR) Expert Panel (Panel) assessed the safety of 16 alkyl ethylhexanoates for use in cosmetics, concluding that these ingredients are safe in cosmetic formulations in the present practices of use and concentrations when formulated to be nonirritating. The alkyl ethylhexanoates primarily function as skin-conditioning agents in cosmetics. The highest concentration of use reported for any of the alkyl ethylhexanoates is 77.3% cetyl ethylhexanoate in rinse-off formulations used near the eye, and the highest leave-on use reported is 52% cetyl ethylhexanoate in lipstick formulations. The Panel reviewed available animal and clinical data related to these ingredients, and the similarities in structure, properties, functions, and uses of ingredients from previous CIR assessments on constituent alcohols that allowed for extrapolation of the available toxicological data to assess the safety of the entire group. PMID:26684798

  20. Structural features of a series of S-alkylated and non-S-alkylated aminothiolate nickel(II) complexes

    Science.gov (United States)

    Chohan, B. S.

    2014-12-01

    The structural aspects of a family of S-alkylated complexes, generated by reacting iodoacetamide or iodoethanol with two mononuclear Ni(II) diaminodithiolate complexes are discussed. The S-alkylation reactions were investigated with particular attention paid to the size of the chelate ring that straps the N,N'-methylamine donors. In one complex the N-methyl groups are cis to each other and in the other they are trans. Both complexes undergo S-alkylation with two equivalents of either reagent, that coordinates through the pendant oxygen to the Ni(II), forming dications with an N2S2O2 ligand donor set. Crystal structures of [NiC12H26N4O2S2]I2 · MeOH, [NiC12H28N2O2S2]I2, and [NiC13H30N2O2S2]I2 · 1/2 MeOH, are determined by single crystal X-ray analysis. The N-methyl groups in each of the alkylated derivatives are trans to each other, suggesting that the cis configuration is highly unfavored for such complexes in octahedral conformation. Crystal packing data shows that each of the alkylated complexes interacts closely with the iodide counterions, and with solvent if present; some of these interactions include H-bonds. Only the iodoacetamide derivative shows any significant interaction with a neighboring molecule.

  1. SYNTHESIS OF 1-n-ALKYL-3-METHYL- AND 1-n-ALKYL-3- PHENYL-5-PYRAZOLONES AND FORMYL DERIVATIVES

    Directory of Open Access Journals (Sweden)

    J. BELMAR

    2001-12-01

    Full Text Available 3-Methyl- and 3-phenyl-5-pyrazolones were alkylated and formylated. The phenyl derivative was less reactive towards alkylation. However in the formylation step 1-n-alkyl-3-methyl- and 1-n-alkyl-3-phenyl-5-pyrazolones showed no difference in reactivity. The alkylated products exist as 5-pyrazolones in chloroform solutions and in dimethylsulfoxide their structure is a 5-hydroxy-pyrazole. Chloroform and dimethyl sulfoxide solutions of 4-formyl derivatives have a structure that is better described as 4-hydroxymethylene-5-pyrazoloneSe alquiló y formiló 3-metil- y 3-fenil-5-pirazolona. El 3-fenil derivado es menos reactivo en la etapa de alquilación. En la etapa de formilación no hay diferencias entre 1-n-alquil-3-metil- o 1-n-alquil-3-fenil-5-pirazolona. Los productos de alquilación presentan una estructura de 5-pirazolona en cloformo, mientras que en dimetilsulfóxido la estructura es del tipo 5-hidroxipirazol. En estos mismos solventes, los derivados formilados solo presentan una estructura que es descrita como 4-hidroximetilén-5-pirazolona

  2. Noncomparative scaling of aromaticity through electron itinerancy

    International Nuclear Information System (INIS)

    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

  3. Alkylation of benzene with normal olefins from coker distillate

    Energy Technology Data Exchange (ETDEWEB)

    Aboul-Gheit, A.K.; Moustafa, O.F.; Habbib, R.M.

    1985-10-01

    The normal olefins separated from a coker distillate were used to alkylate benzene on catalysts containing silicotungstic acid supported on silica, silica-alumina and activated natural clays. The alkylation activity was found to increase as the surface area and silica/alumina ratio of the catalysts increase, irrespective of the support texture. The activation energy of the reaction was very low (proportional3 k cal mol/sup -1/), assuming catalytic intraparticle diffusion limitation. Equilibrium shift towards dealkylation was observed beyond 300/sup 0/C. (orig.).

  4. Pulse gas chromatographic study of adsorption of substituted aromatics and heterocyclic molecules on MIL-47 at zero coverage.

    Science.gov (United States)

    Duerinck, Tim; Couck, Sarah; Vermoortele, Frederik; De Vos, Dirk E; Baron, Gino V; Denayer, Joeri F M

    2012-10-01

    The low coverage adsorptive properties of the MIL-47 metal organic framework toward aromatic and heterocyclic molecules are reported in this paper. The effect of molecular functionality and size on Henry adsorption constants and adsorption enthalpies of alkyl and heteroatom functionalized benzene derivates and heterocyclic molecules was studied using pulse gas chromatography. By means of statistical analysis, experimental data was analyzed and modeled using principal component analysis and partial least-squares regression. Structure-property relationships were established, revealing and confirming several trends. Among the molecular properties governing the adsorption process, vapor pressure, mean polarizability, and dipole moment play a determining role. PMID:22958218

  5. Molecular pharmacology of hepsulfam, NSC 3296801: identification of alkylated nucleosides, alkylation site, and site of DNA cross-linking.

    Science.gov (United States)

    Streeper, R T; Cotter, R J; Colvin, M E; Hilton, J; Colvin, O M

    1995-04-01

    We have determined that hepsulfam, in common with its structural homologue busulfan, alkylates both free guanosine and GMP in DNA at the 7 nitrogen. Mass spectral analysis of the products of the reaction of hepsulfam with guanosine has identified the mono- and bis-alkylated guanosine adducts. UV spectrophotometry and mass spectrometry were used to confirm that alkylation occurred at the 7 nitrogen by following the formation of the formamidopyrimidyl form of the hepsulfam-guanosine adduct at high pH. We have also isolated and identified 1-guanyl,7-hydroxyheptane, 1-guanyl,7-sulfamylheptane, and 1,7-bis(guanyl)heptane from in vitro reaction mixtures of hepsulfam and calf thymus DNA. We have isolated bis-(7-formamidopyrimidyldeoxyguanosinyl)-heptane from an enzymatic digest of DNA treated with hepsulfam. Finally, we have found that hepsulfam forms interstrand cross-links at 5'-GXC-3' sites in model oligonucleotides. PMID:7882358

  6. UV absorption spectra and kinetics for alkyl and alkyl peroxy radicals originating from di-tert-butyl ether

    DEFF Research Database (Denmark)

    Nielsen, O.J.; Sehested, J.; Langer, S.; Ljungström, E.; Wängberg, I.

    Alkyl, (CH3)(3)COC(CH3)(2)CH2, and alkyl peroxy, (CH3)(3)COC(CH3)(2)CH2O2, radicals from di-tert-butyl ether (DTBE), have been studied in the gas phase at 296 K. A pulse radiolysis UV absorption technique was used to measure the spectra and kinetics. Absorption cross sections were quantified over......) s(-1) was found. The rate constants for the reaction of the alkyl peroxy radicals with NO and NO2 were determined to be (1.8 +/- 0.2) X 10(-12) and (9.9 +/- 1.3) X 10(-12) cm(3) molecule(-1) s(-1), respectively. As a part of the work the rate constants k(F + DTBE) and k(OH + DTBE) were determined to...

  7. Separation and analysis of aromatic hydrocarbons from two Chinese coals

    Institute of Scientific and Technical Information of China (English)

    DING Ming-jie; LI Wen-dian; XIE Rui-lun; ZONG Ying; CAI Ke-ying; PENG Yao-li; ZONG Zhi-min; XIE Rui-lun; WEI Xian-yong

    2008-01-01

    Separation and analysis of aromatic hydrocarbons (AHs) from coals is of considerable significance for both fuel and non-fuel use of the coals. In present work two Chinese bituminous coals were selected for separation of AHs by ultrasonic extraction with CS2 followed by column chromatography using hexane as eluent. A series of AHs were separated from the two coals and analyzed by GC/MS. FTIR was employed to characterize the raw coals and the extracted residues. The results of GC/MS analysis show that the separated AHs are mono- to tetracyclic arenes, among which the principle AHs are alkyl naphthalenes and phenanthrenes. Obvious differences in the composition and the structure of AHs exist between the two coals, i.e., the AHs from Tongting coal tend to be higher rings compared to those from Pingshuo coal both from the variety and from the abundance of the AHs. FFIR analysis shows that the raw and extracted coals are similar in terms of functional groups, suggesting that the composition and structure of CS extract, especially the AHs, from coals can be used to interpret the coal structure to some extent.

  8. Quantum transport through aromatic molecules

    International Nuclear Information System (INIS)

    In this paper, we study the electronic transport properties through aromatic molecules connected to two semi-infinite leads. The molecules are in different geometrical configurations including arrays. Using a nearest neighbor tight-binding approach, the transport properties are analyzed into a Green's function technique within a real-space renormalization scheme. We calculate the transmission probability and the Current-Voltage characteristics as a function of a molecule-leads coupling parameter. Our results show different transport regimes for these systems, exhibiting metal-semiconductor-insulator transitions and the possibility to employ them in molecular devices

  9. Substrate specific hydrolysis of aromatic and aromatic-aliphatic esters in orchid tissue cultures

    OpenAIRE

    Agnieszka Mironowicz; Krystyna Kukułczanka; Antoni Siewiński

    2014-01-01

    We found that tissue cultures of higher plants were able, similarly as microorganisms, to transform low-molecular-weight chemical compounds. In tissue cultures of orchids (Cymbidium 'Saint Pierre' and Dendrobium phalaenopsis) acetates of phenols and aromatic-aliphatic alcohols were hydrolyzed, whereas methyl esters of aromatic and aromatic-aliphatic acids did not undergo this reaction. Acetates of racemic aromatic-aliphatic alcohols were hydrolyzed with distinct enantiospecificity.

  10. Tetra-n-butylammonium Hydroxide: an Efficient Catalyst for N-Alkylation of Pyrimidines and Purines

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    An efficient procedure for N-alkylation of pyrimidines and purines in the presence of tetra-n-butylammonium hydroxide(TBAH) is described. The method is very practical and the alkylation can occur at room temperature and the yields of the N-alkyl pyrimidines and purines were found to be excellent.

  11. 40 CFR 721.5380 - Mixed alkyl phenolic novolak resin (generic).

    Science.gov (United States)

    2010-07-01

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

  12. 40 CFR 721.10143 - Amines, bis (C11-14-branched and linear alkyl).

    Science.gov (United States)

    2010-07-01

    ... linear alkyl). 721.10143 Section 721.10143 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.10143 Amines, bis (C11-14-branched and linear alkyl). (a) Chemical..., bis (C11-14-branched and linear alkyl) (PMN P-06-733; CAS No. 900169-60-0) is subject to...

  13. Ruthenium-Catalyzed Alkylation of Oxindole with Alcohols

    DEFF Research Database (Denmark)

    Jensen, Thomas; Madsen, Robert

    2009-01-01

    An atom-economical and solvent-free catalytic procedure for the mono-3-alkylation of oxindole with alcohols is described. The reaction is mediated by the in situ generated catalyst from RuCl3 center dot xH(2)O and PPh3 in the presence of sodium hydroxide, The reactions proceed in good to excellen...

  14. On the Boiling Points of the Alkyl Halides.

    Science.gov (United States)

    Correia, John

    1988-01-01

    Discusses the variety of explanations in organic chemistry textbooks of a physical property of organic compounds. Focuses on those concepts explaining attractive forces between molecules. Concludes that induction interactions play a major role in alkyl halides and other polar organic molecules and should be given wider exposure in chemistry texts.…

  15. Synthesis of Hydroxytyrosyl Alkyl Ethers from Olive Oil Waste Waters

    Directory of Open Access Journals (Sweden)

    Juan Fernández-Bolaños

    2009-05-01

    Full Text Available The preparation of a new type of derivatives of the naturally occurring antioxidant hydroxytyrosol is reported. Hydroxytyrosyl alkyl ethers were obtained in high yield by a three-step procedure starting from hydroxytyrosol isolated from olive oil waste waters. Preliminary results obtained by the Rancimat method have shown that these derivatives retain the high protective capacity of free hydroxytyrosol.

  16. Ionic liquid containing hydroxamate and N-alkyl sulfamate ions

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-03-15

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

  17. Synthesis of Hydroxytyrosyl Alkyl Ethers from Olive Oil Waste Waters

    OpenAIRE

    2009-01-01

    The preparation of a new type of derivatives of the naturally occurring antioxidant hydroxytyrosol is reported. Hydroxytyrosyl alkyl ethers were obtained in high yield by a three-step procedure starting from hydroxytyrosol isolated from olive oil waste waters. Preliminary results obtained by the Rancimat method have shown that these derivatives retain the high protective capacity of free hydroxytyrosol.

  18. Alkyl Aryl Ether Bond Formation with PhenoFluor**

    OpenAIRE

    Shen, Xiao; Neumann, Constanze N.; Kleinlein, Claudia; Claudia, Nathaniel W.; Ritter, Tobias

    2015-01-01

    An alkyl aryl ether bond formation reaction between phenols and primary and secondary alcohols with PhenoFluor has been developed. The reaction features a broad substrate scope and tolerates many functional groups, and substrates that are challenging for more conventional ether bond forming processes may be coupled. A preliminary mechanistic study indicates reactivity distinct from conventional ether bond formation.

  19. Students' Understanding of Alkyl Halide Reactions in Undergraduate Organic Chemistry

    Science.gov (United States)

    Cruz-Ramirez de Arellano, Daniel

    2013-01-01

    Organic chemistry is an essential subject for many undergraduate students completing degrees in science, engineering, and pre-professional programs. However, students often struggle with the concepts and skills required to successfully solve organic chemistry exercises. Since alkyl halides are traditionally the first functional group that is…

  20. Alkylation of quinolines with trialkyl phosphates Pt. 3

    International Nuclear Information System (INIS)

    Intermolecular direct methyl transfer from the O-methyl group of N-methyl-4-methoxy-quinolinium quaternary salt to the ring nitrogen atom of 4-methoxyquinoline formed as intermediates in the alkylation reaction of 4-quinolone with trimethyl phosphate to N-methyl-4-quinolone was established by using tracer techniques. (author)

  1. Alkylation of quinolines with trialkyl phosphates Pt. 3. Isotopic studies

    Energy Technology Data Exchange (ETDEWEB)

    Dutka, F.; Marton, A.F.; Koemives, T. (Magyar Tudomanyos Akademia Koezponti Kemiai Kutato Intezete, Budapest); Frank, J. (CHINOIN Gyogyszer es Vegyeszeti Termekek Gyara Rt., Budapest (Hungary))

    1981-10-03

    Intermolecular direct methyl transfer from the O-methyl group of N-methyl-4-methoxy-quinolinium quaternary salt to the ring nitrogen atom of 4-methoxyquinoline formed as intermediates in the alkylation reaction of 4-quinolone with trimethyl phosphate to N-methyl-4-quinolone was established by using tracer techniques.

  2. Mononuclear non-heme iron(III) complexes of linear and tripodal tridentate ligands as functional models for catechol dioxygenases: Effect of -alkyl substitution on regioselectivity and reaction rate

    Indian Academy of Sciences (India)

    Mallayan Palaniandavar; Kusalendiran Visvaganesan

    2011-03-01

    Catechol dioxygenases are responsible for the last step in the biodegradation of aromatic molecules in the environment. The iron(II) active site in the extradiol-cleaving enzymes cleaves the C-C bond adjacent to the hydroxyl group, while the iron(III) active site in the intradiol-cleaving enzymes cleaves the C-C bond in between two hydroxyl groups. A series of mononuclear iron(III) complexes of the type [Fe(L)Cl3], where L is the linear -alkyl substituted bis(pyrid-2-ylmethyl)amine, -alkyl substituted -(pyrid-2-ylmethyl)ethylenediamine, linear tridentate 3N ligands containing imidazolyl moieties and tripodal ligands containing pyrazolyl moieties have been isolated and studied as structural and functional models for catechol dioxygenase enzymes. All the complexes catalyse the cleavage of catechols using molecular oxygen to afford both intra- and extradiol cleavage products. The rate of oxygenation depends on the solvent and the Lewis acidity of iron(III) center as modified by the sterically demanding -alkyl groups. Also, our studies reveal that stereo-electronic factors like the Lewis acidity of the iron(III) center and the steric demand of ligands, as regulated by the -alkyl substituents, determine the regioselectivity and the rate of dioxygenation. In sharp contrast to all these complexes, the pyrazole-containing tripodal ligand complexes yield mainly the oxidized product benzoquinone.

  3. Beyond organic chemistry: aromaticity in atomic clusters.

    Science.gov (United States)

    Boldyrev, Alexander I; Wang, Lai-Sheng

    2016-04-28

    We describe joint experimental and theoretical studies carried out collaboratively in the authors' labs for understanding the structures and chemical bonding of novel atomic clusters, which exhibit aromaticity. The concept of aromaticity was first discovered to be useful in understanding the square-planar unit of Al4 in a series of MAl4(-) bimetallic clusters that led to discoveries of aromaticity in many metal cluster systems, including transition metals and similar cluster motifs in solid compounds. The concept of aromaticity has been found to be particularly powerful in understanding the stability and bonding in planar boron clusters, many of which have been shown to be analogous to polycyclic aromatic hydrocarbons in their π bonding. Stimulated by the multiple aromaticity in planar boron clusters, a design principle has been proposed for stable metal-cerntered aromatic molecular wheels of the general formula, M@Bn(k-). A series of such borometallic aromatic wheel complexes have been produced in supersonic cluster beams and characterized experimentally and theoretically, including Ta@B10(-) and Nb@B10(-), which exhibit the highest coordination number in two dimensions. PMID:26864511

  4. Inhibitory Activities of Alkyl Syringates and Related Compounds on Aflatoxin Production

    Directory of Open Access Journals (Sweden)

    Tomohiro Furukawa

    2016-06-01

    Full Text Available Inhibitors of aflatoxin production of aflatoxigenic fungi are useful for preventing aflatoxin contamination in crops. As methyl syringate weakly inhibits aflatoxin production, aflatoxin production inhibitory activities of additional alkyl syringates with alkyl chains from ethyl to octyl were examined. Inhibitory activity toward aflatoxin production of Aspergillus flavus became stronger as the length of the alkyl chains on the esters became longer. Pentyl, hexyl, heptyl, and octyl syringates showed strong activity at 0.05 mM. Heptyl and octyl parabens, and octyl gallate also inhibited aflatoxin production as strongly as octyl syringate. Alkyl parabens and alkyl gallates inhibit the complex II activity of the mitochondrial respiration chain; thus, whether alkyl syringates inhibit complex II activity was examined. Inhibitory activities of alkyl syringates toward complex II also became stronger as the length of the alkyl chains increased. The complex II inhibitory activity of octyl syringate was comparable to that of octyl paraben and octyl gallate. These results suggest that alkyl syringates, alkyl parabens, and alkyl gallates, including commonly used food additives, are useful for aflatoxin control.

  5. Inhibitory Activities of Alkyl Syringates and Related Compounds on Aflatoxin Production.

    Science.gov (United States)

    Furukawa, Tomohiro; Iimura, Kurin; Kimura, Taichi; Yamamoto, Toshiyoshi; Sakuda, Shohei

    2016-01-01

    Inhibitors of aflatoxin production of aflatoxigenic fungi are useful for preventing aflatoxin contamination in crops. As methyl syringate weakly inhibits aflatoxin production, aflatoxin production inhibitory activities of additional alkyl syringates with alkyl chains from ethyl to octyl were examined. Inhibitory activity toward aflatoxin production of Aspergillus flavus became stronger as the length of the alkyl chains on the esters became longer. Pentyl, hexyl, heptyl, and octyl syringates showed strong activity at 0.05 mM. Heptyl and octyl parabens, and octyl gallate also inhibited aflatoxin production as strongly as octyl syringate. Alkyl parabens and alkyl gallates inhibit the complex II activity of the mitochondrial respiration chain; thus, whether alkyl syringates inhibit complex II activity was examined. Inhibitory activities of alkyl syringates toward complex II also became stronger as the length of the alkyl chains increased. The complex II inhibitory activity of octyl syringate was comparable to that of octyl paraben and octyl gallate. These results suggest that alkyl syringates, alkyl parabens, and alkyl gallates, including commonly used food additives, are useful for aflatoxin control. PMID:27338472

  6. Polycyclic aromatic hydrocarbons with SPICA

    CERN Document Server

    Berne, O; Mulas, G; Tielens, A G G M; Goicoechea, J R

    2009-01-01

    Thanks to high sensitivity and 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 G$_0$/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 SPIC...

  7. Pyrolysis of oil shales: influence of particle grain size on polycyclic aromatic compounds in the derived shale oils

    Energy Technology Data Exchange (ETDEWEB)

    Williams, P.T.; Nazzal, J.M. [University of Leeds (United Kingdom). Dept. of Fuel and Energy

    1999-06-01

    Oil shales of different particle grain sizes were pyrolysed in a 10 cm diameter x 100 cm high fluidized-bed reactor under both a nitrogen and a steam atmosphere. The oil shales were from the Kimmeridge clay of Jurassic age from the UK. The influence of particle grain size on the yield and composition of the oil and gases was determined. The gases were analysed for H{sub 2}, CO, CO{sub 2}, CH{sub 4} and other hydrocarbons to C{sub 4}. The condensed oils were analysed for their content of polycyclic aromatic compounds (PAC), including polycyclic aromatic hydrocarbons (PAH), sulphur-PAH (PASH) and nitrogen-PAH (PANH). The oil yield increased with increasing particle grain size. The derived shale oils contained significant concentrations of PAH, PASH and PANH. The concentration of PAC increased with decreasing particle grain size. The PAH consisted mainly of naphthalene, fluorene and phenanthrene and their alkylated homologues, and lower concentrations of fluoranthene, pyrene and chrysene. The PASH identified included benzothiophene and dibenzothiophene, and the PANH identified included indole, carbazole and their alkylated derivatives. Increased secondary reactions linked to the formation of PAC were indicated by the alkene/alkane ratio. The effect of steam was to significantly increase the yield of oil and also to increase the concentration of PAH, PASH and PANH in the derived shale oil compared with using nitrogen as the sweep gas. (author)

  8. Aromatic-aliphatic polyamide/montmorillonite clay nanocomposite materials: Synthesis, nanostructure and properties

    International Nuclear Information System (INIS)

    New type of aromatic-aliphatic polyamide/montmorillonite nanocomposites were produced using solution intercalation technique in dimethylacetamide. The modification of clay was carried out with ammonium salt of long chain alkyl amine. The nanocomposites were probed for organoclay dispersion, mechanical, thermal and water absorption measurements. Formation of delaminated and intercalated nanostructures was confirmed by X-ray diffraction and TEM studies. Improvement in tensile strength and modulus was observed for nanocomposites with optimum organoclay content (8-wt.%). Thermogravimetric analysis indicated an increase in thermal stability of nanocomposites as compared to pristine polyamide. Differential scanning calorimetric results revealed increase in glass transition temperatures (Tg) with augmenting organoclay in the nanocomposites. Water uptake of the nanocomposites reduced than the neat polyamide rendering decreased permeability.

  9. Synthesis and Antioxidant Activity of Alkyl Nitroderivatives of Hydroxytyrosol

    Directory of Open Access Journals (Sweden)

    Elena Gallardo

    2016-05-01

    Full Text Available A series of alkyl nitrohydroxytyrosyl ether derivatives has been synthesized from free hydroxytyrosol (HT, the natural olive oil phenol, in order to increase the assortment of compounds with potential neuroprotective activity in Parkinson’s disease. In this work, the antioxidant activity of these novel compounds has been evaluated using Ferric Reducing Antioxidant Power (FRAP, 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid diammonium salt (ABTS, and Oxygen Radical Scavenging Capacity (ORAC assays compared to that of nitrohydroxytyrosol (NO2HT and free HT. New compounds showed variable antioxidant activity depending on the alkyl side chain length; compounds with short chains (2–4 carbon atoms maintained or even improved the antioxidant activity compared to NO2HT and/or HT, whereas those with longer side chains (6–8 carbon atoms showed lower activity than NO2HT but higher than HT.

  10. Bacteria-driven production of alkyl nitrates in seawater

    Science.gov (United States)

    Kim, Michelle J.; Michaud, Jennifer M.; Williams, Renee; Sherwood, Byron Pedler; Pomeroy, Robert; Azam, Farooq; Burkart, Michael; Bertram, Timothy H.

    2015-01-01

    and ship-borne measurements have shown that the ocean is a large, diffuse source for short chain (C1-C3) gas phase alkyl nitrates (RONO2). Photochemical production of RONO2 has been demonstrated previously as a viable mechanism in surface waters; however, it cannot account for the observed depth profile of RONO2, suggesting an additional, dark RONO2 production mechanism. We present measurements of gas phase C1-C5 alkyl nitrates emitted from seawater in a controlled mesocosm experiment conducted under low-light conditions in a glass-walled wave channel. Ethyl and butyl nitrate emission rates from seawater are strongly correlated with the abundance of heterotrophic bacteria (R2 ≥ 0.89) and show no correlation to chlorophyll a concentration. Controlled flask experiments conducted using ambient and sterile seawater, inoculated with a heterotrophic bacterium, confirm that bacterial driven production of select RONO2 can proceed efficiently in the absence of light.

  11. Branched Alkyl Alcohol Propoxylated Sulfate Surfactants for Improved Oil Recovery

    OpenAIRE

    Wu, Y.; Iglauer, S.; Shuler, P.; Tang, Y.; Goddard, W. A., III

    2010-01-01

    This investigation considers branched alkyl alcohol propoxylated sulfate surfactants as candidates for chemcial enhanced oil recovery (EOR) applications. Results show that these anionic surfactants may be preferred candidates for EOR as they can be effective at creating low interfacial tension (1FT) at dilute concentrations, without requiring an alkaline agent or cosurfactant. In addition, some of the formulations exhibit a low 1FT at high salinity, and hence may be suita...

  12. Synthesis and Characterization of Responsive Poly(Alkyl Methacrylate) Topologies

    OpenAIRE

    Kilian, Lars

    2004-01-01

    Dimethacrylate monomers containing two cleavable tert-butyl ester groups were synthesized and utilized in the synthesis of star-shaped polymers. Star polymer coupling was achieved by reacting the living poly(alkyl methacrylate) using 2,5-dimethyl-2,5-hexanediol dimethacrylate (DHDMA) or dicumyl dimethacrylate (DCDMA). These starshaped polymers were cleaved under hydrolytic conditions, leading to significant reductions in molecular weights. The cleavable star-shaped polymers also underwent unc...

  13. Translation of an aromatic field image

    Science.gov (United States)

    Yastrebov, Anatoliy S.; Makarov, Leonid M.; Protasenya, Sergey V.; Vereshak, Evgeniy V.

    2005-04-01

    As is known, for a person there are possibilities of perception of audio, video, and aromatic information messages by means of touch systems available to him. Such packages of the messages are accepted remotely without direct contact to a message source. Now the direction bound with creation of devices capable to playback aromatic information images is actively developed. Such systems switched on in special transmission channels of information provide adequate perception of information highways describing actual event which happen in the enclosing world. One can present the aromatic-field image through a series of control codes for an aromatic field synthesizer, thereupon it is possible to transmit the image on telecommunication networks. For odor oscillators installation problems in compartments of automobiles, buses as well as of airplanes are widely discussed. In this work we deal with a device for synthesis of an image of an aromatic field which works under the control of a personal computer with an express program. In the given operation, the possibility of remote handle of an image of an aromatic field and, as a corollary, organization of a new tansmission channel for the information on the aromatic-field image through an existing synthesizer is considered.

  14. Polycyclic aromatic hydrocarbons in Northwest Atlantic finfish : available and needed knowledge for monitoring

    International Nuclear Information System (INIS)

    This study addressed some of the human health risk factors associated with polycyclic aromatic hydrocarbons (PAHs). These toxic chemicals degrade with time, depending on their source and structure. However, they can also persist long enough and exist at elevated levels to have a possible toxic risk associated with exposure. Most studies on invertebrates have examined bioaccumulation rather than biotransformation. Biotransformation occurs more readily in vertebrates because they have active mixed function oxygenase enzymes. The fate of the oxidation products is of particular interest because they are associated with the formation of DNA-adducts that have carcinogenic effects. Exposed organisms can be monitored for chemical, biochemical or biological endpoints. This study examined PAH concentrations in small finfish such as capelin, sand lance, American plaice, yellowtail flounder and herring collected from the district of the Northwest Atlantic Fisheries Organization. Variables included pool size, size differences within species, lipid content and location. The exposure routes for bioaccumulation were respiration and feeding. The two sources were combustion and fossil fuels. All samples showed signs of alkylated naphthalene which would have been take up by respiration. They were likely derived from petroleum seeps in the water column. Smaller fish had higher concentrations of 3 alkylated naphthalenes. This paper described the relative concentrations in whole fish and internal organs. Measurements carried out prior to development of the Hibernia oil fields revealed baseline levels. Biotransformation products must yet be measured in order to assess future exposure and effects, particularly with long term exposure to waste water. 7 refs., 1 fig

  15. Synthesis and exfoliation of alkyl-pyridinium/Bi2212 nanohybrids

    Energy Technology Data Exchange (ETDEWEB)

    Iwasaki, M; Enomoto, H [Division of Electronics and Applied Physics, Graduate School of Engineering, Osaka Electro-Communication University, Hatsu-cho 18-8, Neyagawa, Osaka 572-8530 (Japan); Ozaki, H [Department of Electrical Engineering and Bioscience, Waseda University, Ohkubo 3-4-1, Shinjuku-ku, Tokyo 169-8555 (Japan); Lerner, M M, E-mail: h-enomot@isc.osakac.ac.j [Department of Chemistry, Oregon State University, Corvallis, OR 97331-4003 (United States)

    2009-03-01

    Nanohybrids of superconducting Bi{sub 2}Sr{sub 2}CaCu2O{sub 8+d} (Bi2212) with alkyl-pyridinium salts were synthesized by a stepwise intercalation method. HgBr{sub 2} was intercalated into Bi2212 crystal to prepare a precursor before intercalation of alkyl-pyridinium ions. Alkyl-pyridinium (Py-C{sub n}H{sub 2n+1}, where Py = pyridine and n = 4, 12 and 16) was adopted as guest intercalants. Nanohybrids were characterized by X-ray powder diffraction. It is found that the gallery height of Bi2212 host is expanded from 3.07 nm to 8.69 nm (DELTAc = 5.61 nm) in Py-C{sub 16}H{sub 33}/Bi2212. We were successful in preparing transparent colloid of Py-C{sub 16}H{sub 33}/Bi2212 nanohybrid in organic solvent. This colloid is found to be stable for 6 days. Ultrathin films assembled by the layer-by-layer technique from Bi2212 colloids with a cationic polymer were fabricated.

  16. Chemotherapy-induced pulmonary hypertension: role of alkylating agents.

    Science.gov (United States)

    Ranchoux, Benoît; Günther, Sven; Quarck, Rozenn; Chaumais, Marie-Camille; Dorfmüller, Peter; Antigny, Fabrice; Dumas, Sébastien J; Raymond, Nicolas; Lau, Edmund; Savale, Laurent; Jaïs, Xavier; Sitbon, Olivier; Simonneau, Gérald; Stenmark, Kurt; Cohen-Kaminsky, Sylvia; Humbert, Marc; Montani, David; Perros, Frédéric

    2015-02-01

    Pulmonary veno-occlusive disease (PVOD) is an uncommon form of pulmonary hypertension (PH) characterized by progressive obstruction of small pulmonary veins and a dismal prognosis. Limited case series have reported a possible association between different chemotherapeutic agents and PVOD. We evaluated the relationship between chemotherapeutic agents and PVOD. Cases of chemotherapy-induced PVOD from the French PH network and literature were reviewed. Consequences of chemotherapy exposure on the pulmonary vasculature and hemodynamics were investigated in three different animal models (mouse, rat, and rabbit). Thirty-seven cases of chemotherapy-associated PVOD were identified in the French PH network and systematic literature analysis. Exposure to alkylating agents was observed in 83.8% of cases, mostly represented by cyclophosphamide (43.2%). In three different animal models, cyclophosphamide was able to induce PH on the basis of hemodynamic, morphological, and biological parameters. In these models, histopathological assessment confirmed significant pulmonary venous involvement highly suggestive of PVOD. Together, clinical data and animal models demonstrated a plausible cause-effect relationship between alkylating agents and PVOD. Clinicians should be aware of this uncommon, but severe, pulmonary vascular complication of alkylating agents. PMID:25497573

  17. Alkylation of Benzene with Propylene Catalyzed by Ionic Liquids

    Institute of Scientific and Technical Information of China (English)

    Sun Xuewen; Zhao Suoqi

    2006-01-01

    The alkylation of benzene with propylene catalyzed by ionic liquids to obtain cumene was investigated. Propylene conversion and cumene selectivity under mild reaction conditions were improved greatly after the ionic liquid was modified with HCl. Under the conditions of 20 oC, 0.1MPa, 5 min of reaction time, and a molar ratio of benzene to propylene of 10:1, propylene conversion increased from 83.6% to 100%, and cumene selectivity increased from 90.86% to 98.47%. In addition, it was found that the reaction could be carried out in two different stages so as to obtain a better result. At the first stage, the key reaction was alkylation and a higher propylene conversion was obtained at a lower temperature;At the second stage, the key reaction was transalkylation and a higher temperature was used to improve cumene selectivity. The reaction temperature, pressure and the amount of catalyst used in this work were lower than those used in traditional alkylation processes.

  18. Synthesis and exfoliation of alkyl-pyridinium/Bi2212 nanohybrids

    International Nuclear Information System (INIS)

    Nanohybrids of superconducting Bi2Sr2CaCu2O8+d (Bi2212) with alkyl-pyridinium salts were synthesized by a stepwise intercalation method. HgBr2 was intercalated into Bi2212 crystal to prepare a precursor before intercalation of alkyl-pyridinium ions. Alkyl-pyridinium (Py-CnH2n+1, where Py = pyridine and n = 4, 12 and 16) was adopted as guest intercalants. Nanohybrids were characterized by X-ray powder diffraction. It is found that the gallery height of Bi2212 host is expanded from 3.07 nm to 8.69 nm (Δc = 5.61 nm) in Py-C16H33/Bi2212. We were successful in preparing transparent colloid of Py-C16H33/Bi2212 nanohybrid in organic solvent. This colloid is found to be stable for 6 days. Ultrathin films assembled by the layer-by-layer technique from Bi2212 colloids with a cationic polymer were fabricated.

  19. Conservation of medicinal and aromatic plants

    Directory of Open Access Journals (Sweden)

    Šveistytė, Laima

    2016-07-01

    Full Text Available The conservation of medicinal and aromatic plants includes ex situ and in situ methods. The genetic recourses of medicinal and aromatic plants are stored, studied and constantly maintained in the field collections of the Institute of Botany of Nature Research Centre, Kaunas Botanical Garden of Vytautas Magnus University and Aleksandras Stulginskis University of Agriculture. Presently seeds of 214 accessions representing 38 species of medicinal and aromatic plants are stored in a long-term storage in the Plant Gene Bank. The data about national genetic resources are collected and stored in the Central Database of the Plant Gene Bank.

  20. Hexacoordinate bonding and aromaticity in silicon phthalocyanine.

    Science.gov (United States)

    Yang, Yang

    2010-12-23

    Si-E bondings in hexacoordinate silicon phthalocyanine were analyzed using bond order (BO), energy partition, atoms in molecules (AIM), electron localization function (ELF), and localized orbital locator (LOL). Bond models were proposed to explain differences between hexacoordinate and tetracoordinate Si-E bondings. Aromaticity of silicon phthalocyanine was investigated using nucleus-independent chemical shift (NICS), harmonic oscillator model of aromaticity (HOMA), conceptual density functional theory (DFT), ring critical point (RCP) descriptors, and delocalization index (DI). Structure, energy, bonding, and aromaticity of tetracoordinate silicon phthalocyanine were studied and compared with hexacoordinate one. PMID:21105726

  1. Efficient synthesis of N-alkyl-2,7-dihalocarbazoles by simultaneous carbazole ring closure and N-alkylation

    Czech Academy of Sciences Publication Activity Database

    Výprachtický, Drahomír; Kmínek, Ivan; Pokorná, Veronika; Cimrová, Věra

    2012-01-01

    Roč. 68, č. 25 (2012), s. 5075-5080. ISSN 0040-4020 R&D Projects: GA MŠk(CZ) 1M06031; GA ČR GAP106/12/0827 Institutional research plan: CEZ:AV0Z40500505 Institutional support: RVO:61389013 Keywords : carbazole ring closure * carbazole alkylation * heterocycles Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 2.803, year: 2012

  2. Pulse shape discrimination in non-aromatic plastics

    International Nuclear Information System (INIS)

    Recently it has been demonstrated that plastic scintillators have the ability to distinguish neutrons from gamma rays by way of pulse shape discrimination (PSD). This discovery has lead to new materials and new capabilities. Here we report our work with the effects of aromatic, non-aromatic, and mixed aromatic/non-aromatic matrices have on the performance of PSD plastic scintillators

  3. Volatilisation of aromatic hydrocarbons from soil

    DEFF Research Database (Denmark)

    Lindhardt, B.; Christensen, T.H.

    1996-01-01

    The non-steady-state fluxes of aromatic hydrocarbons were measured in the laboratory from the surface of soils contaminated with coal tar Four soil samples from a former gasworks site were used for the experiments. The fluxes were quantified for 11 selected compounds, 4 mono- and 7 polycyclic...... aromatic hydrocarbons, for a period of up to 8 or 16 days. The concentrations of the selected compounds in the soils were between 0.2 and 3,100 mu g/g. The study included the experimental determination of the distribution coefficient of the aromatic hydrocarbons between the sorbed phase and the water under...... saturated conditions. The determined distribution coefficients showed that the aromatic hydrocarbons were more strongly sorbed to the total organic carbon including the coal tar pitch - by a factor of 8 to 25 - than expected for natural organic matter. The fluxes were also estimated using an analytical...

  4. Graphite Oxide and Aromatic Amines : Size Matters

    NARCIS (Netherlands)

    Spyrou, Konstantinos; Calvaresi, Matteo; Diamanti, Evmorfi A. K.; Tsoufis, Theodoros; Gournis, Dimitrios; Rudolf, Petra; Zerbetto, Francesco

    2015-01-01

    Experimental and theoretical studies are performed in order to illuminate, for first time, the intercalation mechanism of polycyclic aromatic molecules into graphite oxide. Two representative molecules of this family, aniline and naphthalene amine are investigated. After intercalation, aniline molec

  5. International congress on aromatic and medicinal plants

    International Nuclear Information System (INIS)

    Full Text : In Morocco, medicinal and aromatic plants occupy an important place in the traditional care system of a large number of local people. They are also economically strong potential, but unfortunately they are not valued enough. Indeed, Morocco by its privileged geographical position in the Mediterranean basin and its floristic diversity (with a total of over 4,200 species and subspecies of which over 500 are recognized as medicinal and aromatic plants), is a leading provider of traditional global market. In this context and given the back label of the natural global, group research and studies on Aromatic and Medicinal Plants (GREPAM), the Faculty of Semlalia and University Cadi Ayyad, organize: the International Congress on Medicinal and Aromatic Plants CIPAM 2009. The organization of this conference is part of scientific research developed by the GREPAM.

  6. Activity relationships for aromatic crown ethers

    CERN Document Server

    Wilson, M J

    1998-01-01

    This thesis involves an investigation of aromatic crown ethers and a study of their binding constants for alkali metals. The study was motivated by the current needs of the semiconductor industry to improve the scavenging of mobile ions from fabricated circuits. A number of aromatic crown ethers have been sulphonated in an attempt to improve their water solubility and cation binding activity. These materials have been extensively studied and their binding activity determined. In collaboration with a molecular modelling study, the effect of ionisable sulphonate groups on the macrocycles' behaviour has been investigated. The broader issue of the effect of substituents in aromatic crown ethers has also been studied with the preparation of a wide range of substituted crown ethers. The cation binding activity of these materials has been found to bear a simple relationship to the electron withdrawing nature of the aromatic substituents. This relationship can be accurately monitored using electronic charge densities...

  7. Comments on Coulomb pairing in aromatic hydrocarbons

    CERN Document Server

    Huber, D L

    2013-01-01

    Recently reported anomalies in the double-photonionization spectra of aromatic molecules such as benzene, naphthalene, anthracene and coronene are attributed to Coulomb-pair resonances of pi electrons.

  8. PROTONATED POLYCYCLIC AROMATIC HYDROCARBONS REVISITED

    International Nuclear Information System (INIS)

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

  9. Dehydrogenative Aromatization of Saturated Aromatic Compounds by Graphite Oxide and Molecular Sieves

    Institute of Scientific and Technical Information of China (English)

    张轩; 徐亮; 王希涛; 马宁; 孙菲菲

    2012-01-01

    Graphite oxide (GO) has attracted much attention of material and catalysis chemists recently. Here we describe a combination of GO and molecular sieves for the dehydrogenative aromatization. GO prepared through improved Hummers method showed high oxidative activity in this reaction. Partially or fully saturated aromatic compounds were converted to their corresponding dehydrogenated aromatic products with fair to excellent conversions and selectivities. As both GO and molecular sieves are easily available, cheap, lowly toxic and have good tolerance to various functional groups, this reaction provides a facile approach toward aromatic compounds from their saturated precursors

  10. Aromatic amines sources, environmental impact and remediation

    OpenAIRE

    Pereira, Luciana; Mondal, P. K.; Alves, M. M.

    2015-01-01

    Aromatic amines are widely used industrial chemicals as their major sources in the environment include several chemical industry sectors such as oil refining, synthetic polymers, dyes, adhesives, rubbers, perfume, pharmaceuticals, pesticides and explosives. They result also from diesel exhaust, combustion of wood chips and rubber and tobacco smoke. Some types of aromatic amines are generated during cooking, special grilled meat and fish, as well. The intensive use and production of these comp...

  11. Aromaticity influencing the thermostability of micellar dispersions

    Energy Technology Data Exchange (ETDEWEB)

    Davis, J.A.; Kunzman, W.J.

    1971-05-11

    A hydrocarbon, having sufficient aromaticity to obtain a stable micellar dispersion at the temperature of the formation, is mixed with a surfactant and aqueous medium for injection into the formation to recover crude oil. Higher reservoir temperatures require a greater degree of aromaticity in the hydrocarbon component of the micellar dispersion. This patent is a continuation of U.S. Patent Number 3,495,660 (item No. 118).

  12. Nonchemical weeding of medicinal and aromatic plants

    OpenAIRE

    Carrubba, Alessandra; Militello, Marcello

    2013-01-01

    Medicinal and aromatic plants are major crops of domestic and industrial interest. Medicinal and aromatic plants are increasingly organically grown to enhance profitability. However, the presence of weeds may lead to a decrease in both yield and quality. Therefore, nonchemical methods of weed control are needed. In this study, mechanical weeding, flaming, stale seedbed, and biodegradable mulch were tested from 2003/2004 to 2006/2007 on coriander, fennel, and psyllium. Biomass and seed yield w...

  13. Chemotaxis of Azospirillum Species to Aromatic Compounds

    OpenAIRE

    Lopez-de-Victoria, Geralyne; Lovell, Charles R.

    1993-01-01

    Chemotaxis of Azospirillum lipoferum Sp 59b and Azospirillum brasilense Sp 7 and Sp CD to malate and to the aromatic substrates benzoate, protocatechuate, 4-hydroxybenzoate, and catechol was assayed by the capillary method and direct cell counts. A. lipoferum required induction by growth on 4-hydroxybenzoate for positive chemotaxis to this compound. Chemotaxis of Azospirillum spp. to all other substrates did not require induction. Maximum chemotactic responses for most aromatic compounds occu...

  14. Safety Assessment of Alkyl PEG/PPG Ethers as Used in Cosmetics.

    Science.gov (United States)

    Fiume, Monice M; Heldreth, Bart; Bergfeld, Wilma F; Belsito, Donald V; Hill, Ronald A; Klaassen, Curtis D; Liebler, Daniel C; Marks, James G; Shank, Ronald C; Slaga, Thomas J; Snyder, Paul W; Andersen, F Alan

    2016-07-01

    The Cosmetic Ingredient Review (CIR) Expert Panel assessed the safety of 131 alkyl polyethylene glycol (PEG)/polypropylene glycol ethers as used in cosmetics, concluding that these ingredients are safe in the present practices of use and concentration described in this safety assessment when formulated to be nonirritating. Most of the alkyl PEG/PPG ethers included in this review are reported to function in cosmetics as surfactants, skin-conditioning agents, and/or emulsifying agents. The alkyl PEG/PPG ethers share very similar physiochemical properties as the alkyl PEG ethers, which were reviewed previously by the CIR Expert Panel and found safe when formulated to be nonirritating. The alkyl PEG ethers differ by the inclusion of PPG repeat units, which are used to fine-tune the surfactant properties of this group. The Panel relied heavily on data on analogous ingredients, extracted from the alkyl PEG ethers and PPG reports, when making its determination of safety. PMID:27383199

  15. Effect of the Ortho Alkylation of Perylene Bisimides on the Alignment and Self-Assembly Properties

    OpenAIRE

    2014-01-01

    The effect of the ortho alkylation of perylene bisimides on the alignment and self-assembly properties has been studied. It was found that the dichroic properties of perylene bisimides in a liquid crystal host can be reversed with a single synthetic step by ortho alkylation. Furthermore, a solvent-induced growth of ultralong organic n-type semiconducting fibrils from non-ortho-alkylated perylene bisimide was observed. Ortho substitution of the perylene bisimide core alters the mode of fibrill...

  16. Coke precursor as an intermediate during the alkylation of isobutane/butene over a solid superacid

    Institute of Scientific and Technical Information of China (English)

    XIE; Wenhua; FU; Qiang

    2004-01-01

    Alkylation of isobutane/butene was conducted on a Brφnsted-Lewis conjugated solid superacid. It is found that some hydrocarbons accumulated on the catalyst surface. These hydrocarbons, as called coke precursor, played an intermediate role at the initial stage of the alkylation before they lead the catalyst to lose its activity. The presence of the intermediate is beneficial to the alkylation between isobutane and butene, while increase the TMP content and TMP/DMH ratio in the products.

  17. Synthesis of Imidates: TFA-Mediated Regioselective Amide Alkylation Using Meerwein's Reagent.

    Science.gov (United States)

    Popov, Kirill; Somfai, Peter

    2016-04-15

    Regioselective O-alkylation of an amide to form the corresponding imidate is a common synthetic problem, often resulting in varying amounts of N-alkylation. Screening existing methods for converting amides to imidates gave inconsistent or irreproducible results, sometimes affording N-alkylamide as the major product. A simple and reliable protocol for amide O-alkylation with complete regioselectivity has been designed, and its scope and efficiency demonstrated on a number of substrates. PMID:27019206

  18. Solar Powered Vapor Absorption System Using Propane And Alkylated Benzene Ab300 Oil

    OpenAIRE

    Al-Dadah, R.K.; Jackson, G.; Rezk, Ahmed

    2011-01-01

    Abstract This paper describes experimental work on a solar assisted vapour absorption air conditioning system using Propane (refrigerant) and Alkylated Benzene (AB300?refrigeration lubrication oil, absorbent). Preliminary experiments to assess the miscibility of propane in various lubricating oils namely Shell Clavus oils 32 and 64 and Alkylated Benzene oils AB150 and AB300 indicated that Propane is most miscible in Alkylated Benzene AB300. The vapour absorption system is a single ...

  19. Highly enantio- and diastereoselective allylic alkylation of Morita-Baylis-Hillman carbonates with allyl ketones

    KAUST Repository

    Tong, Guanghu

    2013-05-17

    The asymmetric allylic alkylation of Morita-Baylis-Hillman (MBH) carbonates with allyl ketones has been developed. The α-regioselective alkylation adducts, containing a hexa-1,5-diene framework with important synthetic value, were achieved in up to 83% yield, >99% ee, and 50:1 dr by using a commercially available Cinchona alkaloid as the catalyst. From the allylic alkylation adduct, a cyclohexene bearing two adjacent chiral centers was readily prepared. © 2013 American Chemical Society.

  20. Effects of alkyl chain lengths of gallates upon enzymatic wool functionalisation

    OpenAIRE

    Gaffar Hossain, Kh. M.; Díaz González, María; Dagá Monmany, José María; Tzanov, Tzanko

    2010-01-01

    The covalent grafting of alkyl gallates on wool through a laccase catalysed reaction in 80/20 (v/v, %)aqueous–ethanol mixture provided in a one-step process a multifunctional textile material with antioxidant, antibacterial and water repellent properties. Gallic acid and its alkyl esters ethyl, propyl, octyl and dodecyl gallate have been enzymatically grafted on wool fibres in order to study the effect of alkyl chain length on wool functional modification. The capacity of laccase to oxidis...

  1. Polynuclear aromatic hydrocarbons for fullerene synthesis in flames

    Science.gov (United States)

    Alford, J. Michael; Diener, Michael D.

    2006-12-19

    This invention provides improved methods for combustion synthesis of carbon nanomaterials, including fullerenes, employing multiple-ring aromatic hydrocarbon fuels selected for high carbon conversion to extractable fullerenes. The multiple-ring aromatic hydrocarbon fuels include those that contain polynuclear aromatic hydrocarbons. More specifically, multiple-ring aromatic hydrocarbon fuels contain a substantial amount of indene, methylnapthalenes or mixtures thereof. Coal tar and petroleum distillate fractions provide low cost hydrocarbon fuels containing polynuclear aromatic hydrocarbons, including without limitation, indene, methylnapthalenes or mixtures thereof.

  2. Aromatic Sulfonium Polyoxomolybdates: Solid-State Photochromic Materials with Tunable Properties.

    Science.gov (United States)

    Kumar, Ashwani; Devi, Manisha; Mamidi, Narsimha; Gonsalves, Kenneth E; Pradeep, Chullikkattil P

    2015-12-14

    A new aromatic sulfonium counter-ion motif for polyoxometalate (POM) clusters with potential for structural and electronic fine-tuning has been designed. Its two derivatives 4-hydroxyphenyl dimethylsulfonium triflate (HPDST) and 4-(allyloxy)phenyl dimethylsulfonium triflate (APDST) exhibit ionic liquid behaviors under ambient conditions. HPDST and APDST are used to develop a series of aromatic sulfonium POM hybrids (HPDS/APDS)n[XMo12 O40] (HPDS and APDS are the cations of HPDST and APDST, respectively; X=P or Si; n=3 or 4), which are tested for photochromic behavior. On exposure to UV light, these POM hybrids undergo color change from yellow to green/blue. The coloration kinetics half lives (t1/2) are less for APDS-based hybrids than for HPDS-based hybrids, suggesting that alkyl substitution on the phenolic group helps to fine-tune the electron availability on the sulfonium moiety and hence to control the photochromic behavior of the POM hybrids. The t1/2 values of these hybrids are considerably lower than those of the reported aliphatic sulfonium POM hybrids. We have also demonstrated the application of photoreduced POM hybrids as catalysts for the reduction of 4-nitrophenol to 4-aminophenol. PMID:26502775

  3. Determination of polycyclic aromatic compounds and heavy metals in sludges from biological sewage treatment plants.

    Science.gov (United States)

    Bodzek, D; Janoszka, B; Dobosz, C; Warzecha, L; Bodzek, M

    1997-07-11

    The procedure of the analysis of polycyclic aromatic hydrocarbons (PAHs) and their derivatives in the sludges from biological sewage treatment plants has been worked out. The analysis included isolation of organic matter from sludges, separation of the extract into fractions of similar chemical character, qualitative-quantitative analysis of individual PAHs and their nitrogenated and oxygenated derivatives. Liquid-solid chromatography, solid-phase extraction and semipreparative band thin-layer chromatography techniques were used for the separation. Capillary gas chromatography-mass spectrometry analysis of the separated fractions enabled identification of more than 21 PAHs, including hydrocarbons which contained 2-6 aromatic rings as well as their alkyl derivatives, 10 oxygen derivatives, 9 nitroarenes, aminoarenes and over 20 azaarenes and carbazoles. Using the capillary gas chromatography-flame ionization detection technique the content of 17 dominant PAHs was determined. The content of heavy metals was determined in investigated sludges with the use of atomic absorption spectrometry. The concentrations of the respective metals could be ranked in the order Cd coal mine wastes, taking into consideration the contents of toxic organic pollutants and heavy metals. PMID:9253190

  4. Toward the accurate analysis of C1-C4 polycyclic aromatic sulfur heterocycles.

    Science.gov (United States)

    Zeigler, Christian; Wilton, Nicholas; Robbat, Albert

    2012-03-01

    Polycyclic aromatic sulfur heterocycles (PASH) are sulfur analogues of polycyclic aromatic hydrocarbons (PAH). Alkylated PAH attract much attention as carcinogens, mutagens, and as diagnostics for environmental forensics. PASH, in contrast, are mostly ignored in the same studies due to the conspicuous absence of gas chromatography/mass spectrometry (GC/MS) retention times and fragmentation patterns. To obtain these data, eight coal tar and crude oils were analyzed by automated sequential GC-GC. Sample components separated based on their interactions with two different stationary phases. Newly developed algorithms deconvolved combinatorially selected ions to identify and quantify PASH in these samples. Simultaneous detection by MS and pulsed flame photometric detectors (PFPD) provided additional selectivity to differentiate PASH from PAH when coelution occurred. A comprehensive library of spectra and retention indices is reported for the C(1)-C(4) two-, three-, and four-ring PASH. Results demonstrate the importance of using multiple fragmentation patterns per homologue (MFPPH) compared to selected ion monitoring (SIM) or extraction (SIE) to identify isomers. Since SIM/SIE analyses dramatically overestimate homologue concentrations, MFPPH should be used to correctly quantify PASH for bioavailability, weathering, and liability studies. PMID:22339202

  5. Methods of producing alkylated hydrocarbons from an in situ heat treatment process liquid

    Science.gov (United States)

    Roes, Augustinus Wilhelmus Maria; Mo, Weijian; Muylle, Michel Serge Marie; Mandema, Remco Hugo; Nair, Vijay

    2009-09-01

    A method for producing alkylated hydrocarbons is disclosed. Formation fluid is produced from a subsurface in situ heat treatment process. The formation fluid is separated to produce a liquid stream and a first gas stream. The first gas stream includes olefins. The liquid stream is fractionated to produce at least a second gas stream including hydrocarbons having a carbon number of at least 3. The first gas stream and the second gas stream are introduced into an alkylation unit to produce alkylated hydrocarbons. At least a portion of the olefins in the first gas stream enhance alkylation.

  6. SYNTHESIS OF N-(ALKYL OR ARYL-2-(1H-BENZOTRIAZOL-1-YL-ACETAMIDES AS SELECTIVE COX-2 INHIBITOR

    Directory of Open Access Journals (Sweden)

    Amruta Patil* and Gita Chaurasia

    2013-11-01

    Full Text Available Microwave assisted organic synthesis (MAOS has emerged as frontier in pharmaceutical research for synthesis of newer drugs and implementing GREEN chemistry. Arylacetamides are pharmaceutically interesting as they show various biological activities such as analgesic, local anesthetic, antiarthritic, antiarrhythmic activities, etc. In arylacetamides the nature of aromatic ring and its substituent is primary determinant for its activity. To serve this purpose, we have decided to substitute arylacetamide with benzotriazole which may exploit the analgesic potential of newly synthesized derivatives i.e N-(Alkyl or Aryl-2-(1H-benzotriazol-1-yl-acetamides and thus it may be helpful in reducing the pain without having side effect of ulcerogenicity.

  7. Saturation properties of 1-alkyl-3-methylimidazolium based ionic liquids.

    Science.gov (United States)

    Rane, Kaustubh S; Errington, Jeffrey R

    2014-07-24

    We study the liquid-vapor saturation properties of room temperature ionic liquids (RTILs) belonging to the homologous series 1-alkyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([Cnmim][NTf2]) using Monte Carlo simulation. We examine the effect of temperature and cation alkyl chain length n on the saturated densities, vapor pressures, and enthalpies of vaporization. These properties are explicitly calculated for temperatures spanning from 280 to 1000 K for RTILs with n = 2, 4, 6, 8, 10, and 12. We also explore how the identity of the anion influences saturation properties. Specifically, we compare results for [C(4)mim][NTf2] with those for 1-butyl-3-methylimidazolium tetrafluoroborate ([C(4)mim][BF4]) and 1-butyl-3-methylimidazolium hexafluorophosphate ([C(4)mim][PF6]). Simulations are completed with a recently developed realistic united-atom force field. A combination of direct grand canonical and isothermal-isobaric temperature expanded ensemble simulations are used to construct phase diagrams. Our results are compared with experimental data and Gibbs ensemble simulation data. Overall, we find good agreement between our results and those measured experimentally. We find that the vapor pressures and enthalpies of vaporization show a strong dependence on the size of the alkyl chain at low temperatures, whereas no particular trend is observed at high temperatures. Finally, we also discuss the effect of temperature on liquid phase nanodomains observed in RTILs with large hydrophobic groups. We do not observe a drastic change in liquid phase structure upon variation of the temperature, which suggests there is not a sharp phase transition between a nanostructured and homogeneous liquid, as has been suggested in earlier studies. PMID:24986360

  8. Monolayer structures of alkyl aldehydes: Odd-membered homologues

    OpenAIRE

    Phillips, T. K.; Clarke, Stuart M.; Castro Arroyo, Miguel Ángel; Millán, Carmen; Medina, Santiago

    2011-01-01

    Crystalline monolayers of three aldehydes with an odd number of carbon atoms in the alkyl chain (C 7, C 9 and C 11) at low coverages are observed by a combination of X-ray and neutron diffraction. Analysis of the diffraction data is discussed and possible monolayer crystal structures are proposed; although unique structures could not be ascertained for all molecules. We conclude that the structures are flat on the surface, with the molecules lying in the plane of the layer. The C 11 homologue...

  9. Monolayer structures of alkyl aldehydes: Odd-membered homologues

    International Nuclear Information System (INIS)

    Crystalline monolayers of three aldehydes with an odd number of carbon atoms in the alkyl chain (C7, C9 and C11) at low coverages are observed by a combination of X-ray and neutron diffraction. Analysis of the diffraction data is discussed and possible monolayer crystal structures are proposed; although unique structures could not be ascertained for all molecules. We conclude that the structures are flat on the surface, with the molecules lying in the plane of the layer. The C11 homologue is determined to have a plane group of either p2, pgb or pgg, and for the C7 homologue the p2 plane group is preferred.

  10. Synthesis and cytotoxic activity of some derivatives of alkyl piperidine.

    Science.gov (United States)

    Jahan, Sarwat; Akhtar, Shamim; Saify, Zafar Saied; Mushtaq, Nousheen; Sial, Ali Akbar; Kamil, Arfa; Arif, Muhammed

    2013-05-01

    Synthesis of novel phenacyl derivatives of alkyl piperidine as cytotoxic agents via simple and single step reaction procedure is going to be reported here. Twelve new compounds were successfully synthesized in moderate yield and in solid form. Their synthesis was confirmed by TLC, melting point, CHN analysis and through different spectral studies such as UV, IR, Mass and proton NMR. The advantages of this synthetic route are simple operation, mild reaction conditions and good yields. These newly synthesized derivatives were extensively explored for their cytotoxicity by brine shrimp lethality assay. PMID:23625425

  11. Alkylating HIV-1 Nef - a potential way of HIV intervention

    Directory of Open Access Journals (Sweden)

    Cai Catherine

    2010-07-01

    Full Text Available Abstract Background Nef is a 27 KDa HIV-1 accessory protein. It downregulates CD4 from infected cell surface, a mechanism critical for efficient viral replication and pathogenicity. Agents that antagonize the Nef-mediated CD4 downregulation may offer a new class of drug to combat HIV infection and disease. TPCK (N-α-p-tosyl-L-phenylalanine chloromethyl ketone and TLCK (N-α-p-tosyl-L-lysine chloromethyl ketone are alkylation reagents that chemically modify the side chain of His or Cys residues in a protein. In search of chemicals that inhibit Nef function, we discovered that TPCK and TLCK alkylated HIV Nef. Methods Nef modification by TPCK was demonstrated on reducing SDS-PAGE. The specific cysteine residues modified were determined by site-directed mutagenesis and mass spectrometry (MS. The effect of TPCK modification on Nef-CD4 interaction was studied using fluorescence titration of a synthetic CD4 tail peptide with recombinant Nef-His protein. The conformational change of Nef-His protein upon TPCK-modification was monitored using CD spectrometry Results Incubation of Nef-transfected T cells, or recombinant Nef-His protein, with TPCK resulted in mobility shift of Nef on SDS-PAGE. Mutagenesis analysis indicated that the modification occurred at Cys55 and Cys206 in Nef. Mass spectrometry demonstrated that the modification was a covalent attachment (alkylation of TPCK at Cys55 and Cys206. Cys55 is next to the CD4 binding motif (A56W57L58 in Nef required for Nef-mediated CD4 downregulation and for AIDS development. This implies that the addition of a bulky TPCK molecule to Nef at Cys55 would impair Nef function and reduce HIV pathogenicity. As expected, Cys55 modification reduced the strength of the interaction between Nef-His and CD4 tail peptide by 50%. Conclusions Our data suggest that this Cys55-specific alkylation mechanism may be exploited to develop a new class of anti HIV drugs.

  12. Suzuki-Miyaura Cross-Coupling Reactions of Unactivated Alkyl Halides Catalyzed by a Nickel Pincer Complex

    OpenAIRE

    Di Franco, Thomas; Boutin, Nicolas; Hu, Xile

    2013-01-01

    A nickel(II) pincer complex, [((N2N)-N-Me)Ni-Cl], was used to catalyze alkyl-alkyl and alkyl-aryl Suzuki-Miyaura coupling reactions of unactivated alkyl halides. The coupling of 9-alkyl-9-borabicyclo[3.3.1]nonane and 9-phenyl-9-borabicyclo[3.3.1]nonane reagents with alkyl halides was achieved in modest to good yields. The reactions tolerated a variety of useful functional groups including ester, ether, furan, thioether, acetal, and Boc groups.

  13. An overview of the AROMAT campaigns

    Science.gov (United States)

    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.

  14. Adsorption behavior of some aromatic compounds on hydrophobic magnetite for magnetic separation

    International Nuclear Information System (INIS)

    Highlights: ► Two kinds of modified hydrophobic magnetites were prepared as an adsorbent. ► The modifications on magnetite were carried out using alkyl chain and phenyl group. ► The aromatic compounds (2 ow ow ow ow (phenol 1.46, benzonitrile 1.56, nitrobenzene 1.86, benzene 2.13, toluene 2.73, chlorobenzene 2.84 and o-dichlorobenzene 3.38) onto hydrophobic magnetite. The hydrophobic magnetites were modified with stearic acid and phenyltrimethoxysilane, and the modification amounts were 9.84 × 10−3 and 4.17 × 10−2 mmol/g, respectively. The aromatic compounds used in this study were divided into 3 groups depending on the log Pow: 1 ow ow ow. The adsorption amounts of above each group on the magnetite at an initial concentration of 100 ppm were 3.62 × 10−3 (nitrobenzene), 1.92 × 10−2 (phenol), 1.13 × 10−1 (chlorobenzene), 2.42 10−1 (benzene), and 3.10 × 10−1 mmol/g (dichlorobenzene), respectively. This indicates that the adsorption behaviors depend on the strength of hydrophobicity of aromatic compounds. The adsorption mechanism for 2 ow ow is hydrophobic interaction and that for 1 ow < 2 is π-electron interaction. The quantitative relationship between the amount of adsorbed compounds and modified functional groups and the fitting for adsorption isotherm models suggested that this adsorption might form a multi-layer adsorption in the most cases.

  15. New spectral deconvolution algorithms for the analysis of polycyclic aromatic hydrocarbons and sulfur heterocycles by comprehensive two-dimensional gas chromatography-quadrupole mass spectrometery.

    Science.gov (United States)

    Antle, Patrick M; Zeigler, Christian D; Gankin, Yuriy; Robbat, Albert

    2013-11-01

    New mass spectral deconvolution algorithms have been developed for comprehensive two-dimensional gas chromatography/quadrupole mass spectrometry (GC × GC/qMS). This paper reports the first use of spectral deconvolution of full scan quadrupole GC × GC/MS data for the quantitative analysis of polycyclic aromatic hydrocarbons (PAH) and polycyclic aromatic sulfur heterocycles (PASH) in coal tar-contaminated soil. A method employing four ions per isomer and multiple fragmentation patterns per alkylated homologue (MFPPH) is used to quantify target compounds. These results are in good agreement with GC/MS concentrations, and an examination of method precision, accuracy, selectivity, and sensitivity is discussed. MFPPH and SIM/1-ion concentration differences are also examined. PMID:24063305

  16. A general alkyl-alkyl cross-coupling enabled by redox-active esters and alkylzinc reagents.

    Science.gov (United States)

    Qin, Tian; Cornella, Josep; Li, Chao; Malins, Lara R; Edwards, Jacob T; Kawamura, Shuhei; Maxwell, Brad D; Eastgate, Martin D; Baran, Phil S

    2016-05-13

    Alkyl carboxylic acids are ubiquitous in all facets of chemical science, from natural products to polymers, and represent an ideal starting material with which to forge new connections. This study demonstrates how the same activating principles used for decades to make simple C-N (amide) bonds from carboxylic acids with loss of water can be used to make C-C bonds through coupling with dialkylzinc reagents and loss of carbon dioxide. This disconnection strategy benefits from the use of a simple, inexpensive nickel catalyst and exhibits a remarkably broad scope across a range of substrates (>70 examples). PMID:27103669

  17. UV absorption spectra and kinetics for alkyl and alkyl peroxy radicals originating from di-tert-butyl ether

    DEFF Research Database (Denmark)

    Nielsen, O.J.; Sehested, J.; Langer, S.;

    1995-01-01

    (CH3)(3)COC(CH3)(2)CH2O2 radicals were found to be (2.9 +/- 0.2) X 10(-11) cm(3) molecule(-1) s(-1) and (2.7 +/- 0.2) X 10(-12) cm(3) molecule(-1) s(-1), respectively. For the reaction of the alkyl radical with O-2 in 1 atm pressure of SF6 a rate constant of (7.2 +/- 1.1) X 10(-13) cm(3) molecule(-1...

  18. Molecular mechanisms of alkylation sensitivity in Indian muntjac cell lines.

    Science.gov (United States)

    Musk, S R; Hatton, D H; Bouffler, S D; Margison, G P; Johnson, R T

    1989-07-01

    The responses of two Indian muntjac cell lines to two monofunctional alkylating agents were investigated. An SV40-transformed line (SVM) had an increased sensitivity to cell killing when compared to the other, euploid line (DM) after exposure both to methyl nitrosourea (MNU) and to dimethylsulphate (DMS) and also exhibited higher frequencies of sister chromatid exchanges (SCEs) following alkylation. The hypersensitivity of SVM to DMS correlates with the defective repair of single-strand breaks that results in the generation of long-lived breaks in the DNA following exposure, leading eventually to the formation of chromosome aberrations. In contrast no difference is seen in the formation of long-lived breaks in the DNA of SVM and DM after treatment with biologically relevant doses of MNU; in this case hypersensitivity may be due to the loss of O6-alkylguanine-DNA-alkyltransferase activity. The conclusion that the hypersensitivites of SVM to MNU and to DMS have different molecular bases is supported by transfection of SVM with plasmids containing the protein coding region of the Escherichia coli ada+ gene; subsequent expression within the cell corrects its hypersensitivity to the cytotoxic and SCE-inducing effects of MNU but has very little influence upon the lethality, SCE induction or the repair of long-lived DNA strand breaks after exposure to DMS. PMID:2544312

  19. Tyrosine-selective protein alkylation using pi-allylpalladium complexes.

    Science.gov (United States)

    Tilley, S David; Francis, Matthew B

    2006-02-01

    A new protein modification reaction has been developed based on a palladium-catalyzed allylic alkylation of tyrosine residues. This technique employs electrophilic pi-allyl intermediates derived from allylic acetate and carbamate precursors and can be used to modify proteins in aqueous solution at room temperature. To facilitate the detection of modified proteins using SDS-PAGE analysis, a fluorescent allyl acetate was synthesized and coupled to chymotrypsinogen A and bacteriophage MS2. The tyrosine selectivity of the reaction was confirmed through trypsin digest analysis. The utility of the reaction was demonstrated by using taurine-derived carbamates as water solubilizing groups that are cleaved upon protein functionalization. This solubility switching technique was used to install hydrophobic farnesyl and C(17) chains on chymotrypsinogen A in water using little or no cosolvent. Following this, the C(17) alkylated proteins were found to associate with lipid vesicles. In addition to providing a new protein modification strategy targeting an under-utilized amino acid side chain, this method provides convenient access to synthetic lipoproteins. PMID:16433516

  20. Differential alkylation-based redox proteomics--Lessons learnt.

    Science.gov (United States)

    Wojdyla, Katarzyna; Rogowska-Wrzesinska, Adelina

    2015-12-01

    Cysteine is one of the most reactive amino acids. This is due to the electronegativity of sulphur atom in the side chain of thiolate group. It results in cysteine being present in several distinct redox forms inside the cell. Amongst these, reversible oxidations, S-nitrosylation and S-sulfenylation are crucial mediators of intracellular redox signalling, with known associations to health and disease. Study of their functionalities has intensified thanks to the development of various analytical strategies, with particular contribution from differential alkylation-based proteomics methods. Presented here is a critical evaluation of differential alkylation-based strategies for the analysis of S-nitrosylation and S-sulfenylation. The aim is to assess the current status and to provide insights for future directions in the dynamically evolving field of redox proteomics. To achieve that we collected 35 original research articles published since 2010 and analysed them considering the following parameters, (i) resolution of modification site, (ii) quantitative information, including correction of modification levels by protein abundance changes and determination of modification site occupancy, (iii) throughput, including the amount of starting material required for analysis. The results of this meta-analysis are the core of this review, complemented by issues related to biological models and sample preparation in redox proteomics, including conditions for free thiol blocking and labelling of target cysteine oxoforms. PMID:26282677

  1. Differential alkylation-based redox proteomics - Lessons learnt

    DEFF Research Database (Denmark)

    Wojdyla, Katarzyna; Rogowska-Wrzesinska, Adelina

    2015-01-01

    Cysteine is one of the most reactive amino acids. This is due to the electronegativity of sulphur atom in the side chain of thiolate group. It results in cysteine being present in several distinct redox forms inside the cell. Amongst these, reversible oxidations, S-nitrosylation and S-sulfenylati......Cysteine is one of the most reactive amino acids. This is due to the electronegativity of sulphur atom in the side chain of thiolate group. It results in cysteine being present in several distinct redox forms inside the cell. Amongst these, reversible oxidations, S-nitrosylation and S......-sulfenylation are crucial mediators of intracellular redox signalling, with known associations to health and disease. Study of their functionalities has intensified thanks to the development of various analytical strategies, with particular contribution from differential alkylation-based proteomics methods....... Presented here is a critical evaluation of differential alkylation-based strategies for the analysis of S-nitrosylation and S-sulfenylation. The aim is to assess the current status and to provide insights for future directions in the dynamically evolving field of redox proteomics. To achieve that we...

  2. Synthesis of the alkylated active metabolite of tipidogrel.

    Science.gov (United States)

    Zhi, Shuang; Xia, Guangping; Liu, Ying; Tao, Zunwei; Chen, Ligong; Liu, Dengke

    2015-04-15

    Tipidogrel (3), an effective anti-platelet drug candidate working by irreversibly inhibiting P2Y12 receptor, holds great promise in overcoming clopidogrel resistance and increasing bioavailability. As a prodrug like other thienopyridines, it metabolizes through thiophene ring opening to form active metabolites 3a and 3b, nevertheless they are easily to form disulfide bond. Derivatization of 3a and 3b via alkylation with MPBr can prevent disulfide conjugation and ensure reliable pharmacokinetic results. Thus, in order to support its pre-clinical studies on efficiencies in the formation of tipidogrel active metabolites, 13a and 13b were synthesized via seven steps of chemosynthesis and incubation with MPBr in rat plasma in vitro. The resulting crude productions were purified by semi-preparative HPLC to give Z configuration 13a and E configuration 13b. In LC-MS/MS spectra, they showed identical fragmentation pattern and retention time with M-13a and M-13b, the MPBr-derivatives of active metabolites of tipidogrel in rats. Thus, 13a and 13b were the anticipated alkylated active metabolite of tipidogrel. In addition, in the nucleophilic substitution of thioacetate with compound 11, besides the anticipated compounds 12a and 12b, their isomers compounds 12c and 12d were detected, whose structures were confirmed and the corresponding mechanism was presented. PMID:25801935

  3. Gas-phase reactions of cyclopropenylidene with protonated alkyl amines.

    Science.gov (United States)

    Lin, Ziqing; Tan, Lei; Yang, Yang; Dai, Mingji; Tureček, František; Ouyang, Zheng; Xia, Yu

    2016-04-21

    Vinylidene carbenes (C3H2) are of high interest to interstellar, combustion, and organic chemistry. Due to their high instability, the direct experimental investigation of their chemical reactivity has rarely been achieved. Herein, we report a first study on the reactions of cyclopropenylidene (c-C3H2) with protonated alkyl amines in the gas phase using a home-built ion trap mass spectrometer. The high gas-phase basicity (GB) of ((1)A1) c-C3H2 (calculated as 920 kJ mol(-1)) facilitates the formation of a proton-bound dimer with protonated amines as the first step in the reaction. The dimer can stay as it is or rearrange to a covalent product. The formation of the covalent complex is highly exothermic and its yield is affected by the GB of alkyl amines. The highest yield (82%) was achieved when the GB of the amine was slightly lower but comparable to that of c-C3H2. Our results demonstrate a new reaction pathway of c-C3H2, which has long been considered as a "dead end" in interstellar carbon chemistry. PMID:26978226

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

    Science.gov (United States)

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

    2015-04-01

    identification and characterization of aromatic and condensed aromatic compounds in WSOC [2]. We proposed threshold values of Xc≥ 2.5000 and Xc≥ 2.7143 as ambiguous minimum criteria for the presence of aromatic structure and condensed aromatic compounds, respectively. The advantage of employing this parameter is that Xc would have a constant value for each proposed core structure regardless the degree of alkylation, and thus visual representation and structural interpretations of the spectra become advantageous for characterizing and comparing complex samples. Diesel particulate matter (DPM) and two atmospheric aerosols collected in the industrial area affected by biomass burning events were used to study the applicability of the proposed criteria for the improved identification of aromatic and condensed aromatic structures in complex mixtures in the FT-ICR mass spectra. References [1] Koch.BP, Dittmar.T. From mass to structure: an aromaticity index for high-resolution mass data of natural organic matter. Rapid Commun. Mass Spectrom. 2006, 20, 926-932 [2] Yassine.MM, Harir.M, Dabek-Zlotorzynska.E, Schmitt-Kopplin.Ph. Structural characterization of organic aerosol using Fourier transform ion cyclotron resonance mass spectrometry: Aromaticity equivalent approach. Rapid Commun. Mass Spectrom. 2014. 28. 2445-2454

  5. Synthesis of 2-substituted tryptophans via a C3- to C2-alkyl migration

    Directory of Open Access Journals (Sweden)

    Michele Mari

    2014-08-01

    Full Text Available The reaction of 3-substituted indoles with dehydroalanine (Dha derivatives under Lewis acid-mediated conditions has been investigated. The formation of 2-substituted tryptophans is proposed to occur through a selective alkylative dearomatization–cyclization followed by C3- to C2-alkyl migration and rearomatization.

  6. Development of Degradable Polymer Composites from Starch and Poly(alkyl cyanoacrylate)

    Science.gov (United States)

    This report describes the development of degradable polymer composites that can be made at room temperature without special equipment. The developed composites are made from poly(alkyl cyanoacrylate) and starch. Alkyl cyanoacrylate monomers are mixed with starch and the polymerization reaction of ...

  7. Versatile assembly of p-carboxylatocalix[4]arene-O-alkyl ethers

    Energy Technology Data Exchange (ETDEWEB)

    Kennedy, Stuart; Teat, Simon J.; Dalgarno, Scott J.

    2009-07-08

    Crystallisation of lower-rim tetra-O-alkylated p-carboxylatocalix[4]arenes from pyridine results in the formation of both bi-layer and pillar type supramolecular motifs. Full alkylation at the calixarene lower rim has significant influence over the supramolecular self-assembly motif, including preclusion of pyridine guest molecules from the calixarene cavity in the solid state.

  8. Alkyl-π engineering in state control toward versatile optoelectronic soft materials

    Science.gov (United States)

    Lu, Fengniu; Nakanishi, Takashi

    2015-02-01

    Organic π-conjugated molecules with extremely rich and tailorable electronic and optical properties are frequently utilized for the fabrication of optoelectronic devices. To achieve high solubility for facile solution processing and desirable softness for flexible device fabrication, the rigid π units were in most cases attached by alkyl chains through chemical modification. Considerable numbers of alkylated-π molecular systems with versatile applications have been reported. However, a profound understanding of the molecular state control through proper alkyl chain substitution is still highly demanded because effective applications of these molecules are closely related to their physical states. To explore the underlying rule, we review a large number of alkylated-π molecules with emphasis on the interplay of van der Waals interactions (vdW) of the alkyl chains and π-π interactions of the π moieties. Based on our comprehensive investigations of the two interactions’ impacts on the physical states of the molecules, a clear guidance for state control by alkyl-π engineering is proposed. Specifically, either with proper alkyl chain substitution or favorable additives, the vdW and π-π interactions can be adjusted, resulting in modulation of the physical states and optoelectronic properties of the molecules. We believe the strategy summarized here will significantly benefit the alkyl-π chemistry toward wide-spread applications in optoelectronic devices.

  9. Rhodium-catalyzed aerobic N-alkylation of sulfonamides with alcohols

    Institute of Scientific and Technical Information of China (English)

    Sun Lin Feng; Chuan Zhi Liu; Qiang Li; Xiao Chun Yu; Qing Xu

    2011-01-01

    By using the famous Wilkinson's catalyst, N-alkylation of sulfonamides can be easily realized under mild aerobic conditions by using alcohols as the alkylating reagent, giving monoalkylated sulfonamides in high yields and selectivities with water produced as the only byproduct. This advantageous aerobic method is potentially general in substrate scope that it can also be applied to other amides, amines and alcohols.

  10. Catalytic Alkylation of 2-Methylfuran with Formalin Using Supported Acidic Ionic Liquids

    DEFF Research Database (Denmark)

    Li, Hu; Shunmugavel, Saravanamurugan; Yang, Song;

    2015-01-01

    Biphasic alkylation of 2-methylfuran (2-MF) with formalin was carried out with a series of SBA-15 supported acidic ionic liquid catalysts (acidic SILCs) under mild reaction conditions. Acidic SILC with sulfonic acid groups (SO3H) and long alkyl chains was observed to have higher catalytic activity...

  11. The Retention Behaviors of Benzene and Its Alkyl Homologues in Microemulsion Electrokinetic Chromatography

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The retention behaviors of benzene and its alkyl homologues in microemulsion electrokinetic chromatography were investigated in both anionic and cationic surfactant MEEKC systems. The effects of the composition of microemulsion on retention time and selectivity were studied. A good linear relationship was obtained between log k' and the carbon number of alkyl chain.

  12. Silicone elastomers with aromatic voltage stabilizers

    DEFF Research Database (Denmark)

    A Razak, Aliff Hisyam; Skov, Anne Ladegaard

    insulation cables.3–5 As an alternative to utilise additives as voltage stabilizers, grafting aromatic compounds to silicone backbones may overcome the common problem of insolubility of the aromatic voltage stabilizer in the silicone elastomers due to phase separation. Preventing phase separation during...... via hydrosilylation by a vinyl-functional crosslinker. The mechanism of electron-trapping by aromatic compounds grafted to silicone backbones in a crosslinked PDMS is illustrated in Fig. 1. The electrical breakdown strength, the storage modulus and the loss modulus of the elastomer were investigated...... attached to the silicone backbone. The dielectric relative permittivity of PDMS-PPMS copolymers remained between 2 to 3 with low conductivity and low dielectric loss as well as high storage moduli with low viscous loss, thereby maintaining the electro-mechanical integrity of the elastomer....

  13. Chemotaxis of Azospirillum species to aromatic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Lopez-de-Victoria, G.; Lovell, C.R. (Univ. of South Carolina, Columbia, SC (United States))

    1993-09-01

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

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

    Science.gov (United States)

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

    2015-04-01

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

  15. Sulfated Alkyl Glucopyranans with Potent Antiviral Activity Synthesized by Ring-Opening Copolymerization of Anhydroglucose and Alkyl Anhydroglucose Monomers

    Directory of Open Access Journals (Sweden)

    Shiming Bai

    2015-01-01

    Full Text Available Sulfated glucopyranans having long alkyl groups were prepared by the ring-opening copolymerization of benzylated 1,6-anhydroglucopyranose with 3-O-octadecyl 1,6-anhydro-β-d-glucopyranose monomers, and subsequent deprotection and sulfation. Water-soluble sulfated glucopyranans with 2.8 and 4.7 mol% of 3-O-octadecyl group and lower molecular weights of M-n = 2.5 × 103–5.1 × 103 have potent anti-HIV activity at 0.05–1.25 μg/mL, even though sulfated polysaccharides with molecular weights below M-n = 6 × 103 had low anti-HIV activity. The interaction with poly-l-lysine as a model compound of proteins was analyzed by SPR, DSL, and zeta potential, indicating that the sulfated 3-O-octadecyl glucopyranans had high association and low dissociation rate constants, and the particle size increased after addition of poly-l-lysine. The anti-HIV activity was induced by electrostatic interaction between sulfate groups and amino groups of poly-l-lysine and by the synergistic effect of the hydrophobic long alkyl chain and hydrophilic sulfated group.

  16. Structural modifications of petroleum asphaltenes by reductive alkylation investigated by TLC-FID

    Energy Technology Data Exchange (ETDEWEB)

    Cagniant, D.; Nosyrev, I.; Cebolla, V.; Vela, J.; Membrado, L.; Gruber, R. [Universite de Metz, Metz (France). Laboratoire de Thermodynamique et d' Analyses Chimiques

    2001-01-01

    The reductive alkylation of a French petroleum asphaltene (Lagrave) was studied with potassium in THF, in absence of an electron transfer reagent. From the number of butyl and benzyl groups added to the starting asphaltene, the difference of reactivity of the alkyl reagents, butyl iodide and benzyl bromide, was pointed out. Special attention was focused on the cleavage of C-S and C-O linkages in relation to the structural modifications. From the number of hydrogen atoms added during the reduction step, it was concluded that the sulphide linkages are mainly of aryl-S-aryl, aryl-S-alkyl or alkyl-S-alkyl types. The TLC-FID (Iatroscan) analysis was found to be very suitable to follow the 'depolymerization' process of the asphaltene, qualitatively as well as quantitatively, by the application hydrocarbon group type analysis. 23 refs., 2 figs., 5 tabs.

  17. Building blocks for ionic liquids: Vapor pressures and vaporization enthalpies of 1-(n-alkyl)-imidazoles

    International Nuclear Information System (INIS)

    Highlights: → We measured vapor pressures of the 1-(n-alkyl)-imidazoles by transpiration method. → Variations on the alkyl chain length n were C3, C5-C7, and C9-C10. → Enthalpies of vaporization were derived from (p, T) dependencies. → Enthalpies of vaporization at 298.15 K were linear dependent on the chain length. - Abstract: Vapor pressures of the linear 1-(n-alkyl)-imidazoles with the alkyl chain C3, C5-C7, and C9-C10 have been measured by the transpiration method. The molar enthalpies of vaporization ΔlgHm of these compounds were derived from the temperature dependencies of vapor pressures. A linear correlation of enthalpies of vaporization ΔlgHm (298.15 K) of the 1-(n-alkyl)-imidazoles with the chain length has been found.

  18. Alkylating ability of carbohydrate oxetanes: Practical synthesis of bolaform skeleton derivative

    Directory of Open Access Journals (Sweden)

    Hadžić Pavle A.

    2015-01-01

    Full Text Available Alkylating ability of oxetane ring in carbohydrate structure was investigated and flexible method for bolaform amphiplile skeleton construction with xylose as polar heads is proposed. The method is based on oxetane ring opening in easily accessible 3,5-anhydro-1,2-O-cyclohexylidenexylofuranose (1. One step nitrogen alkylation in terminal diamines with 1 gave basic cationic bolaform skeleton with xylose as potential polar heads and deliberately chosen length of non polar spacer. Under similar experimental conditions, but with appropriate molar ratio of alkylating agent, alkylation reaction provide for selective monoalkylation of diamines. Successful alkylation in xanthine series (theophylline was also achieved with 1, giving a new 5-deoxy-5-(7´-theophyllineamino-α-D-xylofuranose derivative.

  19. Alkyl chain length impacts the antioxidative effect of lipophilized ferulic acid in fish oil enriched milk

    DEFF Research Database (Denmark)

    Sørensen, Ann-Dorit Moltke; Lyneborg, Karina Sieron; Villeneuve, Pierre; Jacobsen, Charlotte

    2015-01-01

    Lipophilization of phenolics by esterification with fatty alcohols may alter their localization in an emulsion and thereby their antioxidant efficacy. In this study, synthesized unbranched alkyl ferulates were evaluated as antioxidants in fish oil enriched milk. Lipid oxidation was determined by...... peroxide values and concentration of volatile oxidation products. A cut-off effect in the antioxidant efficacy in relation to the alkyl chain length was observed. The most efficient alkyl ferulate was methyl ferulate followed by ferulic acid and butyl ferulate, whereas octyl ferulate was prooxidative and...... the prooxidative effect increased further with an increment in the alkyl chain length from C8 to C12. Further elongation of the alkyl chain length to C16 and C20 resulted in weak prooxidative effects to weak antioxidative effects depending on the different volatile oxidation compounds developed....

  20. Quality Control of 1-Alkyl-3-methylimidazolium Ionic Liquid Precursors with HPLC

    Institute of Scientific and Technical Information of China (English)

    张延强; 张建敏; 陈玉涣; 张锁江

    2007-01-01

    A high performance liquid chromatography (HPLC) method was proposed to monitor the synthesis and purification of the 1-alkyl-3-methylimidazolium ionic liquid precursors from alkylation of 1-methylimidazole with alkyl halides and determine the purity of final products. The results showed that separation of 1-methylimidazole from the precursors could be obtained under the HPLC performance conditions such as cation exchange column, acetonitrile/KH2PO4 aqueous solution and 209 nm wavelength. The content of unreacted 1-methylimidazole in the precursors could be easily calculated from their corresponding HPLC peak areas with the calibration curve of 1-methylimidazole. The retention times of the 1-alkyl-3-methylimidazolium ionic liquid precursors decreased with their increasing alkyls, and the ionic liquids with the same cation and different anions had almost the same retention times.

  1. Production of aromatics from di- and polyoxygenates

    Energy Technology Data Exchange (ETDEWEB)

    Beck, Taylor; Blank, Brian; Jones, Casey; Woods, Elizabeth; Cortright, Randy

    2016-08-02

    Methods, catalysts, and reactor systems for producing in high yield aromatic chemicals and liquid fuels from a mixture of oxygenates comprising di- and polyoxygenates are disclosed. Also disclosed are methods, catalysts, and reactor systems for producing aromatic chemicals and liquid fuels from oxygenated hydrocarbons such as carbohydrates, sugars, sugar alcohols, sugar degradation products, and the like; and methods, catalysts, and reactor systems for producing the mixture of oxygenates from oxygenated hydrocarbons such as carbohydrates, sugars, sugar alcohols, sugar degradation products, and the like. The disclosed catalysts for preparing the mixture of oxygenates comprise a Ni.sub.nSn.sub.m alloy and a crystalline alumina support.

  2. Global aromatics supply. Today and tomorrow

    Energy Technology Data Exchange (ETDEWEB)

    Bender, M. [BASF SE, Ludwigshafen (Germany)

    2013-11-01

    Aromatics are the essential building blocks for some of the largest petrochemical products in today's use. To the vast majority they are consumed to produce intermediates for polymer products and, hence, contribute to our modern lifestyle. Their growth rates are expected to be in line with GDP growth in future. This contrasts the significantly lower growth rates of the primary sources for aromatics - fuel processing and steam cracking of naphtha fractions. A supply gap can be expected to open up in future for which creative solutions will be required. (orig.)

  3. Electron beam irradiation effects on aromatic polymers

    International Nuclear Information System (INIS)

    Electron irradiation effects on aromatic polymers having various molecular structures were studied to elucidate the following subjects; (1) relation between radiation stability and molecular structure of repeating units, (2) mechanism of deterioration and (3) adaptability to matrix resin for radiation resistant FRP. Results are summarized as follows: (1) An order of radiation stability of units is; imide ring > diphenyl ether, diphenyl ketone > aromatic amide >> bis-phenol A > diphenyl sulphone. (2) Poly (ether-ether-ketone) and most polyimide are crosslinkable but polysulphones and polyarylate are chain degradation type polymers. (3) Newly developed thermoplastic polyimides have possibilities for use as matrix materials in radiation resistant FRP. (author)

  4. Fluorescence method for enzyme analysis which couples aromatic amines with aromatic aldehydes

    Science.gov (United States)

    Smith, R.E.; Dolbeare, F.A.

    1980-10-21

    Analysis of proteinases is accomplished using conventional amino acid containing aromatic amine substrates. Aromatic amines such as 4-methoxy-2-naphthylamine (4M2NA), 2-naphthylamine, aminoisophthalic acid dimethyl ester, p-nitroaniline, 4-methoxy-1-aminofluorene and coumarin derivatives resulting from enzymatic hydrolysis of the substrate couples with aromatic aldehydes such as 5-nitrosalicylaldehyde (5-NSA), benzaldehyde and p-nitrobenzaldehyde to produce Schiff-base complexes which are water insoluble. Certain Schiff-base complexes produce a shift from blue to orange-red (visible) fluorescence. Such complexes are useful in the assay of enzymes. No Drawings

  5. Fluorescence method for enzyme analysis which couples aromatic amines with aromatic aldehydes

    Science.gov (United States)

    Smith, Robert E.; Dolbeare, Frank A.

    1979-01-01

    Analysis of proteinases is accomplished using conventional amino acid containing aromatic amine substrates. Aromatic amines such as 4-methoxy-2-naphthylamine (4M2NA), 2-naphthylamine, aminoisophthalic acid dimethyl ester, p-nitroaniline, 5-methoxy-1-aminofluorene and coumarin derivatives resulting from enzymatic hydrolysis of the substrate couples with aromatic aldehydes such as 5-nitrosalicylaldehyde (5-NSA), benzaldehyde and p-nitrobenzaldehyde to produce Schiff-base complexes which are water insoluble. Certain Schiff-base complexes produce a shift from blue to orange-red (visible) fluorescence. Such complexes are useful in the assay of enzymes.

  6. Reactivity patterns of transition metal hydrides and alkyls

    International Nuclear Information System (INIS)

    The complex PPN+ CpV(CO)3H- (Cp=eta5-C5H5 and PPN = (Ph3P)2) was prepared in 70% yield and its physical properties and chemical reactions investigated. PPN+ CpV(CO)3H- reacts with a wide range of organic halides. The organometallic products of these reactions are the vanadium halides PPN+[CpV(C)3X]- and in some cases the binuclear bridging hydride PPN+ [CpV(CO)3]2H-. The borohydride salt PPN+[CpV(CO)3BH4]- has also been prepared. The reaction between CpV(CO)3H- and organic halides was investigated and compared with halide reductions carried out using tri-n-butyltin hydride. Results demonstrate that in almost all cases, the reduction reaction proceeds via free radical intermediates which are generated in a chain process, and are trapped by hydrogen transfer from CpV(CO)3H-. Sodium amalgam reduction of CpRh(CO)2 or a mixture of CpRh(CO)2 and CpCo(CO)2 affords two new anions, PPN+ [Cp2Rh3(CO)4]- and PPN+[Cp2RhCo(CO)2]-. CpMo(CO)3H reacts with CpMo(CO)3R (R=CH3,C2H5, CH2C6H5) at 25 to 500C to produce aldehyde RCHO and the dimers [CpMo(CO)3]2 and [CpMo(CO)2]2. In general, CpV(CO)3H- appears to transfer a hydrogen atom to the metal radical anion formed in an electron transfer process, whereas CpMo(CO)3H transfers hydride in a 2-electron process to a vacant coordination site. The chemical consequences are that CpV(CO)3H- generally reacts with metal alkyls to give alkanes via intermediate alkyl hydride species whereas CpMo(CO)3H reacts with metal alkyls to produce aldehyde, via an intermediate acyl hydride species

  7. Thermal stability of the aromatic fraction of Safaniya crude oil (Middle East): experimental study, kinetic scheme by molecular classes and geochemical implications; Stabilite thermique de la fraction aromatique de l'huile brute safaniya (Moyen-Orient): etude experimentale, schema cinetique par classes moleculaires et implications geochimiques

    Energy Technology Data Exchange (ETDEWEB)

    Al Darouich, T.

    2005-07-15

    The thermal evolution of reservoir oils is controlled by the kinetics of cracking reactions. The present work is concerned with the study of the thermal stability of the light aromatic components (C{sub 6}-C{sub 14}) of crude oils under geological conditions. The aim is to predict this stability through a mode l derived from laboratory pyrolyses. The light cut < 250 deg. C of Safaniya crude oil, corresponding to the C{sub 15} components, was obtained by fractionated distillation; pure aromatic fraction was then separated by liquid chromatography. Detailed molecular characterisation of the aromatic fraction was acquired using HPLC, GC and GC/MS. Then, quantified individual aromatic compounds were lumped into six molecular classes: BTXN, methyl-aromatics, alkyl-aromatics, naphthenic-aromatics, indene and sulphur - containing aromatics. Pyrolyses of the aromatic fraction were performed in gold tubes at 100 bars and different temperature/time conditions in a wide range (1 to 93%) of global conversion. Pyrolysis effluents were analysed and lumped into classes. The pyrolysis data were used to elaborate a semi - empirical kinetic scheme of 13 stoichiometric reactions for the primary and secondary cracking of the unstable classes. The scheme kinetic parameters were first estimated, and then numerically optimised, with the constraints of mass balance and hydrogen conservation. A set of pyrolysis experiments was performed at 375 deg.C under high pressures: 400, 800 and 1200 bars. Increasing slowing down in conversion rate with increasing pressure was thus observed compared to experiments at 100 bars. A slight selective effect of pressure on the different aromatic classes of the charge and on the product distribution was evidenced. The extrapolation of the kinetic model to the conditions of Elgin Field (North Sea) showed that pressure effect should shift the thermal cracking of light aromatics to higher temperatures by almost 8 deg. C. (author)

  8. 40 CFR 721.10108 - Naphthalenedisulfonic acid, hydrozy-[[[(hydroxyl-disulfo-naphthaleneyl)azo]-alkyl(C=1-5...

    Science.gov (United States)

    2010-07-01

    ...- -alkyl(C=1-5)-(sulfoalkoxy)cyclic]azo]-substituted azo-, metal salt (generic). 721.10108 Section 721... Naphthalenedisulfonic acid, hydrozy- -alkyl(C=1-5)-(sulfoalkoxy)cyclic]azo]-substituted azo-, metal salt (generic). (a... generically as naphthalenedisulfonic acid, hydrozy- -alkyl(C=1-5)-(sulfoalkoxy)cyclic]azo]-substituted...

  9. Fluorescent aromatic sensors and their methods of use

    Science.gov (United States)

    Meador, Michael A. (Inventor); Tyson, Daniel S. (Inventor); Ilan, Ulvi F. (Inventor)

    2012-01-01

    Aromatic molecules that can be used as sensors are described. The aromatic sensors include a polycyclic aromatic hydrocarbon core with a five-membered imide rings fused to the core and at least two pendant aryl groups. The aromatic sensor molecules can detect target analytes or molecular strain as a result of changes in their fluorescence, in many cases with on-off behavior. Aromatic molecules that fluoresce at various frequencies can be prepared by altering the structure of the aromatic core or the substituents attached to it. The aromatic molecules can be used as sensors for various applications such as, for example, the detection of dangerous chemicals, biomedical diagnosis, and the detection of damage or strain in composite materials. Methods of preparing aromatic sensor molecules are also described.

  10. Enhanced performance of alkylated graphene reinforced polybutylene succinate nanocomposite

    Science.gov (United States)

    Abidin, A. S. Zainal; Yusoh, K.; Jamari, S. S.; Abdullah, A. H.; Ismail, Z.

    2016-07-01

    Polybutylene succinate (PBS) was being grafted with octadecylamine-functionalized graphene oxide (GO-ODA) to produce novel PBS/GO-ODA nanocomposites by solution blending technique. Alkylated graphene oxide has superhydrophobic surface thus improved the affinity of the filler with low polar polymer such as PBS. The structure and compatibility of the filler and nanocomposites were being characterized using Fourier transform infrared spectroscopy (FTIR), Universal tensile machine (UTM) and thermogravimetric analysis (TGA). Enhancement of tensile strength and Young's modulus by 30% and 165% respectively was achieved with cooperation of 0.5% GO-ODA loading. The functionalization of GO-ODA in PBS matrix leads to the improvement in the nanocomposites properties.

  11. Fluorescent RNA labeling using self-alkylating ribozymes.

    Science.gov (United States)

    Sharma, Ashwani K; Plant, Joshua J; Rangel, Alexandra E; Meek, Kirsten N; Anamisis, April J; Hollien, Julie; Heemstra, Jennifer M

    2014-08-15

    The ability to fluorescently label specific RNA sequences is of significant utility for both in vitro and live cell applications. Currently, most RNA labeling methods utilize RNA-nucleic acid or RNA-protein molecular recognition. However, in the search for improved RNA labeling methods, harnessing the small-molecule recognition capabilities of RNA is rapidly emerging as a promising alternative. Along these lines, we propose a novel strategy in which a ribozyme acts to promote self-alkylation with a fluorophore, providing a robust, covalent linkage between the RNA and the fluorophore. Here we describe the selection and characterization of ribozymes that promote self-labeling with fluorescein iodoacetamide (FIA). Kinetic studies reveal a second-order rate constant that is on par with those of other reactions used for biomolecular labeling. Additionally, we demonstrate that labeling is specific to the ribozyme sequences, as FIA does not react nonspecifically with RNA. PMID:24896502

  12. Breastfeeding as an Exposure Pathway for Perfluorinated Alkylates

    DEFF Research Database (Denmark)

    Mogensen, Ulla B; Grandjean, Philippe; Nielsen, Flemming; Weihe, Pal; Budtz-Jørgensen, Esben

    2015-01-01

    Perfluorinated alkylate substances (PFASs) are widely used and have resulted in human exposures worldwide. PFASs occur in breast milk, and the duration of breastfeeding is associated with serum-PFAS concentrations in children. To determine the time-dependent impact of this exposure pathway, we...... examined the serum concentrations of five major PFASs in a Faroese birth cohort at birth, and at ages 11, 18, and 60 months. Information about the children's breastfeeding history was obtained from the mothers. The trajectory of serum-PFAS concentrations during months with and without breastfeeding was...... examined by linear mixed models that accounted for the correlations of the PFAS measurements for each child. The models were adjusted for confounders such as body size. The duration of exclusive breastfeeding was associated with increases of most PFAS concentrations by up to 30% per month, with lower...

  13. Novel alkyl substituted polyanilines/molybdenum disulfide nanocomposites

    International Nuclear Information System (INIS)

    Polyaniline (PANI), poly(N-methyl aniline) (PMA), poly(ethyl aniline) (PEA) and poly(propyl aniline) (PPA) were synthesized in their salt form, and then characterized by FT-IR spectroscopy and charge transport measurements. The solubility of the polymers was tested in a variety of solvents and N-methylformamide (NMF) was found to be the best solvent. While polyaniline gave a colloidal suspension in NMF, the solubility of the polymer increased with increasing length of the alkyl group, resulting in a concomitant decrease in electrical conductivity. The solubility of the polymers was exploited and their intercalation was performed in molybdenum disulfide by using the exfoliating/restacking property of LiMoS2. Powder X-ray diffraction showed that genuine intercalation compounds were formed. The resulting nanocomposites were also characterized by thermogravimetric analysis (TGA)

  14. Monolayer structures of alkyl aldehydes: Odd-membered homologues

    Energy Technology Data Exchange (ETDEWEB)

    Phillips, T.K. [BP Institute, Department of Chemistry, University of Cambridge, Cambridge (United Kingdom); Clarke, S.M., E-mail: stuart@bpi.cam.ac.u [BP Institute, Department of Chemistry, University of Cambridge, Cambridge (United Kingdom); Bhinde, T. [BP Institute, Department of Chemistry, University of Cambridge, Cambridge (United Kingdom); Castro, M.A.; Millan, C. [Instituto Ciencia de los Materiales de Sevilla, Departamento de Quimica Inorganica (CSIC-Universidad de Sevilla) (Spain); Medina, S. [Centro de Investigacion, Tecnologia e Innovacion de la Universidad de Sevilla (CITIUS), Sevilla (Spain)

    2011-03-01

    Crystalline monolayers of three aldehydes with an odd number of carbon atoms in the alkyl chain (C{sub 7}, C{sub 9} and C{sub 11}) at low coverages are observed by a combination of X-ray and neutron diffraction. Analysis of the diffraction data is discussed and possible monolayer crystal structures are proposed; although unique structures could not be ascertained for all molecules. We conclude that the structures are flat on the surface, with the molecules lying in the plane of the layer. The C{sub 11} homologue is determined to have a plane group of either p2, pgb or pgg, and for the C{sub 7} homologue the p2 plane group is preferred.

  15. Branched alkyl alcohol propoxylated sulfate surfactants for improved oil recovery

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Y.; Iglauer, S.; Shuler, P.; Tang, Y. [California Institute of Technology, Covina, CA (US). Power, Environmental and Energy Research (PEER) Center; Goddard, W.A. III [California Institute of Technology, Pasadena, CA (United States). Materials and Process Simulation Center

    2010-05-15

    This investigation considers branched alkyl alcohol propoxylated sulfate surfactants as candidates for chemical enhanced oil recovery (EOR) applications. Results show that these anionic surfactants may be preferred candidates for EOR as they can be effective at creating low interfacial tension (IFT) at dilute concentrations, without requiring an alkaline agent or cosurfactant. In addition, some of the formulations exhibit a low IFT at high salinity, and hence may be suitable for use in more saline reservoirs. Adsorption tests onto kaolinite clay indicate that the loss of these surfactants can be comparable to or greater than other types of anionic surfactants. Surfactant performance was evaluated in oil recovery core flood tests. Selected formulations recovered 35-50% waterflood residual oil even with dilute 0.2 wt% surfactant concentrations from Berea sandstone cores. (orig.)

  16. [Methaemoglobinaemia induced by ingestion of alkyl nitrite, "poppers"].

    Science.gov (United States)

    Kragsfeldt, Celina Thelberg; Nissen, Christoffer B; Brandt, Frans

    2016-08-22

    We present a case report of an 18-year-old male who was referred to the emergency department with evidence of methaemoglobinaemia. He presented with classic symptoms with peripheral cyanosis and hypoxia. Arterial blood gas showed a methaemoglobin level of 36%. This was caused by ingestion of alkyl nitrate, a widespread party drug called "poppers". When inhaled it causes euphoria, reduced pain and relaxation of the anal sphincter, but oral use may induce life-threatening methaemoglobinaemia. The treatment of choice is the antidote methylene blue. After treatment the patient regained full recovery and was discharged on the following day. We discuss classic symptoms, diagnosis and treatment of intoxication with methylene blue. PMID:27549005

  17. Separation of Scintillation and Cherenkov Lights in Linear Alkyl Benzene

    CERN Document Server

    Li, Mohan; Yeh, Minfang; Wang, Zhe; Chen, Shaomin

    2015-01-01

    To separate scintillation and Cherenkov lights in water-based liquid scintillator detectors is a desired feature for future neutrino and proton decay researches. Linear alkyl benzene (LAB) is one important ingredient of a water-based liquid scintillator being developed. In this paper we observed a good separation of scintillation and Cherenkov lights in an LAB sample. The rising and decay times of the scintillation light of the LAB were measured to be $(7.7\\pm3.0)\\ \\rm{ns}$ and $(36.6\\pm2.4)\\ \\rm{ns}$, respectively, while the full width [-3$\\sigma$, 3$\\sigma$] of the Cherenkov light was 12 ns dominated by the time resolution of our photomultiplier tubes. The light yield of the scintillation was measured to be $(1.01\\pm0.12)\\times10^3\\ \\rm{photons}/\\rm{MeV}$.

  18. Synthesis, docking study and relaxant effect of 2-alkyl and 2-naphthylchromones on rat aorta and guinea-pig trachea through phosphodiesterase inhibition.

    Science.gov (United States)

    Rodríguez-Ramos, Fernando; Navarrete, Andrés; González-Andrade, Martín; Alarcón, Carlos; Aguilera-Cruz, Alejandro; Reyes-Ramírez, Adelfo

    2013-10-01

    Chromone (4), which form the base structure of various flavonoids isolated as natural products, is capable of relaxing smooth muscle. This is relevant to the treatment of high blood pressure, asthma and chronic obstructive pulmonary disease. The former disorder involves the contraction of vascular smooth muscle (VSM), and the latter two bronchoconstriction of airway smooth muscle (ASM). One of the principal mechanisms by which flavonoids relax muscle tissue is the inhibition of phosphodiesterases (PDEs), present in both VSM and ASM. Therefore, a study was designed to analyze the structure-activity relationship of chromone derivatives in vaso- and bronchorelaxation through the inhibition of PDE. Docking studies showed that these chromones bind at the catalytic site of PDEs. Consequently, we synthesized analogs of chromones substituted at position C-2 with alkyl and naphthyl groups. These compounds were synthesized from 2-hydroxyacetophenone and acyl chlorides in the presence of DBU and pyridine, modifying the methodology reported for the synthesis of 3-acylchromones by changing the reaction temperature from 80 to 30°C and using methylene chloride as solvent, yielding the corresponding phenolic esters 10a-10h. These compounds were cyclized with an equivalent of DBU, pyridine as solvent, and heated at reflux temperature, yielding the chromones 11a-11h. Evaluation of the vasorelaxant effect of 4, 11a-11h on rat aorta demonstrated that potency decreases with branched alkyl groups. Whereas the EC50 of compound 11d (substituted by an n-hexyl group) was 8.64±0.39 μM, that of 11f (substituted by an isobutyl group) was 14.58±0.64 μM. Contrarily, the effectiveness of the compound is directly proportional to the length of the alkyl chain, as evidenced by the increase in maximal effect of compound 11c versus 11d (66% versus 100%) and 11e versus 11f (60% versus 96%). With an aromatic group like naphthyl as the C-2 substituent, the effectiveness was only 43%. All compounds

  19. Polycyclic Aromatic Hydrocarbons as Plausible Prebiotic Membrane Components

    OpenAIRE

    Groen, Joost; Deamer, David W.; Kros, Alexander; Ehrenfreund, Pascale

    2012-01-01

    Aromatic molecules delivered to the young Earth during the heavy bombardment phase in the early history of our solar system were likely to be among the most abundant and stable organic compounds available. The Aromatic World hypothesis suggests that aromatic molecules might function as container elements, energy transduction elements and templating genetic components for early life forms. To investigate the possible role of aromatic molecules as container elements, we incorporated different p...

  20. Alkaline earth alkyl insertion chemistry of in situ generated aminoboranes.

    Science.gov (United States)

    Bellham, Peter; Hill, Michael S; Kociok-Köhn, Gabriele; Liptrot, David J

    2013-01-21

    Reactions of equimolar quantities of secondary amine boranes, R(2)NH·BH(3), with the homoleptic group 2 alkyl compounds [M{CH(SiMe(3))(2)}(2)(THF)(2)] (M = Mg, Ca, Sr) provide the alkyl group 2 amido borane derivatives [M{CH(SiMe(3))(2)}{NR(2)BH(3)}(THF)](2). While the strontium derivatives of reactions with dimethylamine and pyrrolidine borane are stable and isolable compounds, the analogous magnesium and calcium compounds are found to be unstable at room temperature. Studies of the thermolysis of the alkylstrontium derivatives have allowed this instability to be rationalised as a result of β-hydride elimination, the facility of which varies with changing M(2+) charge density, to form the products of M-C insertion of H(2)B=NR(2). Subsequent to this process, alkylaminoboranes, [HB(NR(2)){CH(SiMe(3))(2)}], are observed to form through a further suggested β-hydride elimination reaction. This chemistry is also extended to the reaction of the primary amine borane (t)BuNH(2)·BH(3) with [Sr{CH(SiMe(3))(2)}(2)(THF)(2)]. In this case the crystal structure of a heteroleptic species, which may be considered as a tetrameric aggregate of two [Sr{CH(SiMe(3))(2)}{(NH(t)Bu)BH(3)}(2)] anions and two cationic [Sr{(NH(t)Bu)(BH(3))}(THF)(2)] components, has been determined. Kinetic studies of the reactions of [M{CH(SiMe(3))(2)}(2)(THF)(2)] (M = Mg, Ca, Sr) with dimethylamine borane have also been undertaken and describe a complex mechanism in which the barriers to formation of the various intermediate species are a consequence of M(2+) radius and resultant charge density as well as the steric demands of the coordinated amidoborane ligands. PMID:23070304

  1. Synthesis, characterization and chemoprotective activity of polyoxovanadates against DNA alkylation.

    Science.gov (United States)

    Nunes, Giovana G; Bonatto, Ana C; de Albuquerque, Carla G; Barison, Andersson; Ribeiro, Ronny R; Back, Davi F; Andrade, André Vitor C; de Sá, Eduardo L; Pedrosa, Fábio de O; Soares, Jaísa F; de Souza, Emanuel M

    2012-03-01

    The alkylation of pUC19 plasmid DNA has been employed as a model reaction for the first studies on chemoprotective action by a mixed-valence (+IV/+V) polyoxovanadate. A new, non-hydrothermal route for the high yield preparation of the test compound is described. The deep green, microcrystalline solid A was isolated after a three-day reaction in water at 80°C and 1 atm, while the reaction at 100°C gave green crystals of B. Both solids were structurally characterized by X-ray diffractometry and FTIR, EPR, NMR and Raman spectroscopies. Product A was identified as (NH(4))(2)V(3)O(8), while B corresponds to the spherical polyoxoanion [V(15)O(36)(Cl)](6-), isolated as the NMe(4)(+) salt. The lack of solubility of A in water and buffers prevented its use in DNA interaction studies, which were then carried out with B. Complex B was also tested for its ability to react with DNA alkylating agents by incubation with diethylsulphate (DES) and dimethylsulphate (DMS) in both the absence and presence of pUC19. For DMS, the best results were obtained with 10 mM of B (48% protection); with DES, this percentage increased to 70%. The direct reaction of B with increasing amounts of DMS in both buffered (PIPES 50 mM) and non-buffered aqueous solutions revealed the sequential formation of several vanadium(IV), vanadium(V) and mixed-valence aggregates of different nuclearities, whose relevance to the DNA-protecting activity is discussed. PMID:22265837

  2. Microfungal alkylation and volatilization of selenium adsorbed by goethite.

    Science.gov (United States)

    Peitzsch, Mirko; Kremer, Daniel; Kersten, Michael

    2010-01-01

    Selenium adsorbed in the oxyanionic form by Fe-oxides like goethite is considered of benefit for long-term stabilization of (79)Se under near field conditions of radionuclide waste disposal sites. However, microbe-mediated volatilization of the uranium fission product (79)Se has not yet been considered for risk assessment based on the use of the water-solid distribution coefficient K(D). We have performed incubation experiments in a ternary system selenium-microbe-goethite and show that mycobiota including the common black microfungi genera Alternaria alternata are capable of volatilizing the Se even if immobilized by goethite. The microfungi were incubated in a standardized nutrient broth suspension with 10 g L(-1) of the oxide target under defined conditions. Volatile organic selenium (VOSe) species formed in the head space of the culture flasks were sampled and measured directly by a cryotrapping cryofocusing gas chromatographic system coupled with ICP-MS detection (CT-CF-GC-ICP-MS). Alkylated VOSe species were found at the tens to hundreds ng m(-3) levels dominated by dimethyl selenide (DMSe) and dimethyl diselenide (DMDSe). The total amount of DMSe released into the 80-mL headspace volume within the 21 days of incubation was up to 1.12 +/- 0.17 nmol and 0.48 +/- 0.12 nmol for systems without and with goethite amendment, respectively. Alkylation rates of up to 0.1 mumol Se per day and g biomass cannot be neglected as a potential fission product mobilization pathway, unless the inherent radioactivity is proven to prevent any such microbial activity on the long-term. Otherwise it may lead to an onsite accumulation of (79)Se through evapoconcentration in the enclosed underground caverns. PMID:20039743

  3. Electronic Aromaticity Index for Large Rings

    CERN Document Server

    Matito, Eduard

    2015-01-01

    We introduce a new electronic aromaticity index, AV1245, consisting in the average of the 4-center MCI values along the ring that keep a positional relationship of 1,2,4,5. AV1245 measures the extent of transferability of the delocalized electrons between bonds 1-2 and 4-5, which is expected to be large in conjugated circuits and, therefore, in aromatic molecules. A new algorithm for the calculation of MCI for large rings is also introduced and used to produce the data for the calibration of the new aromaticity index. AV1245 does not rely on reference values, does not suffer from large numerical precision errors, and it does not present any limitation on the nature of atoms, the molecular geometry or the level of calculation. It is a size-extensive measure with a small computational cost that grows linearly with the number of ring members. Therefore, it is specially suitable to study the aromaticity of large molecular rings as those occurring in belt-shaped M\\"obius structures or porphyrins.

  4. Extremely long aromatics: Diastereomerically pure [19]helicene

    Czech Academy of Sciences Publication Activity Database

    Nejedlý, Jindřich; Rybáček, Jiří; Stará, Irena G.; Starý, Ivo

    Praha: Czech Chemical Society, 2015. s. 119. [Liblice 2015. Advances in Organic , Bioorganic and Pharmaceutical Chemistry /50./. 06.11.2015-08.11.2015, Olomouc] R&D Projects: GA ČR(CZ) GA14-29667S Institutional support: RVO:61388963 Keywords : helically chiral aromatics * helicenes * [2+2+2] cycloisomerisation Subject RIV: CC - Organic Chemistry

  5. Aromatic cytokinins in micropropagated potato plants

    Czech Academy of Sciences Publication Activity Database

    Baroja, F. E.; Aguirreolea, J.; Martínková, Hana; Hanuš, Jan; Strnad, Miroslav

    2002-01-01

    Roč. 40, č. 3 (2002), s. 217-224. ISSN 0981-9428 R&D Projects: GA MŠk OC 844.10; GA ČR GA301/02/0475 Institutional research plan: CEZ:AV0Z5038910 Keywords : Acclimatization * Aromatic cytokinins * Micropropagation Subject RIV: CE - Biochemistry Impact factor: 1.582, year: 2002

  6. Discovering Chemical Aromaticity Using Fragrant Plants

    Science.gov (United States)

    Schneider, Tanya L.

    2010-01-01

    Introductory organic chemistry is often perceived as inaccessible by students. This article describes a method used to link organic chemistry to everyday experience, asking students to explore whether fragrant molecules are also aromatic in the chemical sense. Students were engaged in this activity, excited about their results, and performed well…

  7. Thermoset/Thermoplastic Aromatic Polyamides for Composites

    Science.gov (United States)

    St. Clair, T. L.; St. Clair, A. K.; Barrick, J. D.; Wolfe, J. F.; Greenwood, T. D.

    1983-01-01

    Aromatic polyamides are processed at relatively low temperature, then heat-treated to attain high softening temperature required when polyamides are used as matrix resins in structural composites. New polyamides are compatable with organic fibers often used as reinforcing agents in such composites Pendent propargyl groups serve as latent cross-linking agents in new series of polyamide resins.

  8. An electronic aromaticity index for large rings.

    Science.gov (United States)

    Matito, Eduard

    2016-04-28

    We introduce a new electronic aromaticity index, AV1245, consisting of an average of the 4-center multicenter indices (MCI) along the ring that keeps a positional relationship of 1, 2, 4, 5. AV1245 measures the extent of transferability of the delocalized electrons between bonds 1-2 and 4-5, which is expected to be large in conjugated circuits and, therefore, in aromatic molecules. A new algorithm for the calculation of MCI for large rings is also introduced and used to produce the data for the calibration of the new aromaticity index. AV1245 does not rely on reference values, does not suffer from large numerical precision errors, and it does not present any limitation on the nature of atoms, the molecular geometry or the level of calculation. It is a size-extensive measure with low computational cost that grows linearly with the number of ring members. Therefore, it is especially suitable to study the aromaticity of large molecular rings such as those occurring in belt-shaped Möbius structures or porphyrins. The analysis of AV1245 in free-base and bis-metalated Pd [32]octaphyrins(1,0,1,0,1,0,1,0) completes this study. PMID:26878146

  9. Fused aromatic thienopyrazines: structure, properties and function

    KAUST Repository

    Mondal, Rajib

    2010-01-01

    Recent development of a fused aromatic thieno[3.4-b]pyrazine system and their application in optoelectronic devices are reviewed. Introduction of a fused aromatic unit followed by side chain engineering, dramatically enhanced the charge carrier mobility in thin film transistor devices and mobilities up to 0.2 cm2/Vs were achieved. The optoelectronic properties of these fused aromatic thienopyrazine polymers (Eg = 1.3 to 1.6 eV, HOMO = -4.9 to -5.2 V) were tuned by introduction of various fused aromatic rings within thienopyrazine. By balancing the fundamental properties of these polymers, both high charge carrier mobilities and moderate PCEs in solar cells were achieved. Further, effects of copolymerizing units are discussed. Low band gap semiconducting polymer (Eg ∼ 1 eV) with high field effect mobility (0.044 cm2/Vs) was obtained using cyclopentadithiophene as copolymerizing unit. Finally, a molecular design approach to enhance the absorption coefficients is discussed, which resulted in improved power conversion efficiency in bulk heterojunction solar cells. © 2010 The Royal Society of Chemistry.

  10. Silicone elastomers with aromatic voltage stabilizers

    DEFF Research Database (Denmark)

    A Razak, Aliff Hisyam; Skov, Anne Ladegaard

    enhanced electrical breakdown strength due to delocalized pi-electrons of aromatic rings attached to the silicone backbone. The dielectric relative permittivity of PDMS-PPMS copolymers remained between 2 to3 with low conductivity and low dielectric loss as well as high storage moduli with low viscousloss...

  11. Dihydrodiol dehydrogenase and polycyclic aromatic hydrocarbon metabolism

    Energy Technology Data Exchange (ETDEWEB)

    Smithgall, T.E.

    1986-01-01

    Carcinogenic activation of polycyclic aromatic hydrocarbons by microsomal monoxygenases proceeds through trans-dihydrodiol metabolites to diol-epoxide ultimate carcinogens. This thesis directly investigated the role of dihydrodiol dehydrogenase, a cytosolic NAD(P)-linked oxidoreductase, in the detoxification of polycyclic aromatic trans-dihydrodiols. A wide variety of non-K-region trans-dihydrodiols were synthesized and shown to be substrates for the homogeneous rat liver dehydrogenase, including several potent proximate carcinogens derived from 7,12-dimethylbenz(a)anthracene, 5-methylchrysene, and benzo(a)pyrene. Since microsomal activation of polycyclic aromatic hydrocarbons is highly stereospecific, the stereochemical course of enzymatic trans-dihydrodiol oxidation was monitored using circular dichroism spectropolarimetry. The major product formed from the dehydrogenase-catalyzed oxidation of the trans-1,2-dihydrodiol of naphthalene was characterized using UV, IR, NMR, and mass spectroscopy, and appears to be 4-hydroxy-1,2-naphthoquinone. Mass spectral analysis suggests that an analogous hydroxylated o-quinone is formed as the major product of benzo(a)pyrene-7,8-dihydrodiol oxidation. Enzymatic oxidation of trans-dihydrodiols was shown to be potently inhibited by all of the major classes of the nonsteroidal antiinflammatory drugs. Enhancement of trans-dihydrodiol proximate carcinogen oxidation may protect against possible adverse effects of the aspirin-like drugs, and help maintain the balance between activation and detoxification of polycyclic aromatic hydrocarbons.

  12. Scavenging ratio of polycyclic aromatic compounds in rain and snow at the Athabasca oil sands region

    Directory of Open Access Journals (Sweden)

    L. Zhang

    2014-07-01

    Full Text Available Athabasca oil sands industry in northern Alberta, Canada is a possible source of polycyclic aromatic compounds (PACs. Monitored PACs, including polycyclic aromatic hydrocarbons (PAHs, alkylated PAHs, and dibenzothiophenes, in precipitation and in air at three near-source sites in the Fort MacKay and Fort McMurray area during May 2011 to August 2012 were analyzed to generate a database of scavenging (or washout ratios (Wt for PACs scavenged by both snow and rain. Median precipitation and air concentrations of parent PAHs over the May 2011 to August 2012 period ranged from 0.3–184.9 (chrysene ng L−1 and 0.01–3.9 (naphthalene ng m−3, respectively, which were comparable to literature values. Higher concentrations in precipitation and air were observed for alkylated PAHs and dibenzothiophenes. The median precipitation and air concentrations were 11.3–646.7 (C3-fluoranthene/pyrene ng L−1 and 0.21–16.9 (C3-naphthalene ng m−3, respectively, for alkylated PAHs, and 8.5–530.5 (C4-dibenzothiophene ng L−1 and 0.13–6.6 (C2-dibenzothiophene ng m−3 for dibenzothiophenes and their alkylated derivatives. Median Wt over the measurement period were 6100–1.1 × 106 from snow scavenging and 350–2.3 × 105 from rain scavenging depending on the PAC species. Median Wt for parent PAHs were within the range of those observed at other urban and suburban locations. But Wt for acenaphthylene in snow samples was 2–7 times higher. Some individual snow and rain samples exceeded literature values by a factor of 10. Wt for benzo(apyrene, dibenz(a,hanthracene, and benzo(g,h,iperylene in snow samples had reached 107, which is the maximum for PAH snow scavenging ratios reported in literature. From the analysis of data subsets, Wt for particulate-phase dominant PACs were 14–20 times greater than gas-phase dominant PACs in snow samples and 7–20 times greater than gas-phase dominant PACs in rain samples. Wt from snow scavenging was ∼9 times greater

  13. Determination of polycyclic aromatic hydrocarbons in urban street dusts and their source materials by capillary gas chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Takada, Hideshige; Onda, Tomoko; Ogura, Norio (Tokyo Univ. of Agriculture and Technology (Japan))

    1990-08-01

    Molecular distributions of polycyclic aromatic hydrocarbons (PAHs) in street dust samples collected from the Tokyo metropolitan area were determined by capillary gas chromatography following HPLC fractionation. Sixty-four compounds including three- to six-ring PAHs and sulfur heterocyclics were identified by capillary GC/MS. Total PAH concentrations were in the range of a few micrograms per gram of dust. The source materials (automobile exhaust, asphalt, fuel-oil combustion products) were also analyzed. The PAH profile, especially relative abundance of alkyl-PAHs and sulfur-containing heterocyclics, indicated that PAHs in the street dusts on the heavily trafficked streets are strongly affected by automobile exhaust and those in the residential area have a somewhat more significant contribution from combustion products in stationary sources. With both types of dusts, asphalt is through to contribute only a minor part of their PAHs.

  14. 40 CFR 721.5762 - Aromatic aldehyde phenolic resin (generic).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Aromatic aldehyde phenolic resin... Specific Chemical Substances § 721.5762 Aromatic aldehyde phenolic resin (generic). (a) Chemical substance... aromatic aldehyde phenolic resin (PMN P-01-573) is subject to reporting under this section for...

  15. 40 CFR 721.2673 - Aromatic epoxide resin (generic).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Aromatic epoxide resin (generic). 721... Substances § 721.2673 Aromatic epoxide resin (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as aromatic epoxide resin (PMN...

  16. Localized enrichment of polycyclic aromatic hydrocarbons in soil, spruce needles, and lake sediments linked to in-situ bitumen extraction near Cold Lake, Alberta

    International Nuclear Information System (INIS)

    The extraction of bitumen from the Alberta oil sands using in-situ technologies is expanding at a rapid rate; however, investigations into the environmental impacts of oil sands development have focused on surface mining in the Athabasca region. We measured polycyclic aromatic hydrocarbons (PAH) in soils, spruce needles, and lake sediment cores in the Cold Lake oil sands region to provide a historical and spatial perspective on PAH contamination related to in-situ extraction activities. A pronounced increase in PAH concentrations was recorded in one of two study lakes (Hilda Lake) corresponding to the onset of commercial bitumen production in ∼1985. Distance from extraction rigs was not an important predictor of PAH concentrations in soils, although two samples located near installations were elevated in alkyl PAHs. Evidence of localized PAH contamination in Hilda Lake and two soil samples suggests that continued environmental monitoring is justified to assess PAH contamination as development intensifies. -- Highlights: •In-situ bitumen extraction linked to rise in alkyl PAHs in one of two study lakes. •Alkyl PAHs elevated in two soil samples. •PAH contamination likely related to effluent sources, not atmospheric deposition. -- PAHs in sediments and soils were generally low in areas adjacent to in-situ bitumen extraction rigs in the Cold Lake Alberta oil sands, but evidence of localized contamination at some sites was evident

  17. Plasmids and aromatic degradation in Sphingomonas for bioremediation : Aromatic ring cleavage genes in soil and rhizosphere

    OpenAIRE

    SipilÀ, Timo

    2009-01-01

    Microbial degradation pathways play a key role in the detoxification and the mineralization of polyaromatic hydrocarbons (PAHs), which are widespread pollutants in soil and constituents of petroleum hydrocarbons. In microbiology the aromatic degradation pathways are traditionally studied from single bacterial strains with capacity to degrade certain pollutant. In soil the degradation of aromatics is performed by a diverse community of micro-organisms. The aim of this thesis was to study biode...

  18. Origin of polycyclic aromatic hydrocarbons in lake sediments of the Mackenzie Delta.

    Science.gov (United States)

    Headley, John V; Marsh, Philip; Akre, Christine J; Peru, Kerry M; Lesack, Lance

    2002-08-01

    The concentrations and distribution of polycyclic aromatic hydrocarbons (PAHs) were assessed in sediment cores from among 14 lakes from three regions comprising a transect across the central Mackenzie Delta. PAHs were consistently found in the lake sediments, with parent concentrations in the 20-200 ng/g range. Concentrations were generally independent of depth in the sediment cores and this pattern was similar among the 3 regions of the delta. Concentrations increased in a westerly direction among the regions. For some lakes, the concentration of PAHs decreased with decreasing flooding frequency, and decreasing sedimentation rates. For the latter, maximum concentrations occurred at shallower depths within the sediment cores as flooding frequency among the lakes decreased. The distributions of C0-C4 alkylated 2- and 3- ring PAHs were consistent with a petrogenic origin, while the corresponding distribution of 4-ring PAHs appears to be more consistent with a biogenic or pyrogenic origin. Based on relative contributions to the overall PAH budget, a petrogenic source appears to be dominant. However, the pyrene/fluoranthene ratio is more consistent with a source derived from peat. The alkylated PAH profiles are inconsistent with those in the Athabasca River system, and supports a previously published hypothesis that the contribution of PAHs from the Athabasca oil sands to the lower Mackenzie River is minimal. A double ratio plot of chrysene vs dibenzothiophene, diagnostic of weathering, suggests most weathering occurred before the sediments were deposited in the lakes, while a double ratio plot of dibenzothiophene vs phenanthrene suggests a common source of PAHs across the delta, despite differing water sources from east to west across the delta. PAH inputs to the delta appear to mirror sediment inputs documented in previous work, where high sediment input from the Mackenzie mainstem during high floods dominates the delta sediment influx and masks any influence of the

  19. Aag DNA glycosylase promotes alkylation-induced tissue damage mediated by Parp1.

    Directory of Open Access Journals (Sweden)

    Jennifer A Calvo

    2013-04-01

    Full Text Available Alkylating agents comprise a major class of front-line cancer chemotherapeutic compounds, and while these agents effectively kill tumor cells, they also damage healthy tissues. Although base excision repair (BER is essential in repairing DNA alkylation damage, under certain conditions, initiation of BER can be detrimental. Here we illustrate that the alkyladenine DNA glycosylase (AAG mediates alkylation-induced tissue damage and whole-animal lethality following exposure to alkylating agents. Aag-dependent tissue damage, as observed in cerebellar granule cells, splenocytes, thymocytes, bone marrow cells, pancreatic β-cells, and retinal photoreceptor cells, was detected in wild-type mice, exacerbated in Aag transgenic mice, and completely suppressed in Aag⁻/⁻ mice. Additional genetic experiments dissected the effects of modulating both BER and Parp1 on alkylation sensitivity in mice and determined that Aag acts upstream of Parp1 in alkylation-induced tissue damage; in fact, cytotoxicity in WT and Aag transgenic mice was abrogated in the absence of Parp1. These results provide in vivo evidence that Aag-initiated BER may play a critical role in determining the side-effects of alkylating agent chemotherapies and that Parp1 plays a crucial role in Aag-mediated tissue damage.

  20. Kinetic study of the anaerobic biodegradation of alkyl polyglucosides and the influence of their structural parameters.

    Science.gov (United States)

    Ríos, Francisco; Fernández-Arteaga, Alejandro; Lechuga, Manuela; Jurado, Encarnación; Fernández-Serrano, Mercedes

    2016-05-01

    This paper reports a study of the anaerobic biodegradation of non-ionic surfactants alkyl polyglucosides applying the method by measurement of the biogas production in digested sludge. Three alkyl polyglucosides with different length alkyl chain and degree of polymerization of the glucose units were tested. The influence of their structural parameters was evaluated, and the characteristics parameters of the anaerobic biodegradation were determined. Results show that alkyl polyglucosides, at the standard initial concentration of 100 mgC L(-1), are not completely biodegradable in anaerobic conditions because they inhibit the biogas production. The alkyl polyglucoside having the shortest alkyl chain showed the fastest biodegradability and reached the higher percentage of final mineralization. The anaerobic process was well adjusted to a pseudo first-order equation using the carbon produced as gas during the test; also, kinetics parameters and a global rate constant for all the involved metabolic process were determined. This modeling is helpful to evaluate the biodegradation or the persistence of alkyl polyglucosides under anaerobic conditions in the environment and in the wastewater treatment. PMID:26820643

  1. mTOR target NDRG1 confers MGMT-dependent resistance to alkylating chemotherapy

    Science.gov (United States)

    Weiler, Markus; Blaes, Jonas; Pusch, Stefan; Sahm, Felix; Czabanka, Marcus; Luger, Sebastian; Bunse, Lukas; Solecki, Gergely; Eichwald, Viktoria; Jugold, Manfred; Hodecker, Sibylle; Osswald, Matthias; Meisner, Christoph; Hielscher, Thomas; Rübmann, Petra; Pfenning, Philipp-Niklas; Ronellenfitsch, Michael; Kempf, Tore; Schnölzer, Martina; Abdollahi, Amir; Lang, Florian; Bendszus, Martin; von Deimling, Andreas; Winkler, Frank; Weller, Michael; Vajkoczy, Peter; Platten, Michael; Wick, Wolfgang

    2014-01-01

    A hypoxic microenvironment induces resistance to alkylating agents by activating targets in the mammalian target of rapamycin (mTOR) pathway. The molecular mechanisms involved in this mTOR-mediated hypoxia-induced chemoresistance, however, are unclear. Here we identify the mTOR target N-myc downstream regulated gene 1 (NDRG1) as a key determinant of resistance toward alkylating chemotherapy, driven by hypoxia but also by therapeutic measures such as irradiation, corticosteroids, and chronic exposure to alkylating agents via distinct molecular routes involving hypoxia-inducible factor (HIF)-1alpha, p53, and the mTOR complex 2 (mTORC2)/serum glucocorticoid-induced protein kinase 1 (SGK1) pathway. Resistance toward alkylating chemotherapy but not radiotherapy was dependent on NDRG1 expression and activity. In posttreatment tumor tissue of patients with malignant gliomas, NDRG1 was induced and predictive of poor response to alkylating chemotherapy. On a molecular level, NDRG1 bound and stabilized methyltransferases, chiefly O6-methylguanine-DNA methyltransferase (MGMT), a key enzyme for resistance to alkylating agents in glioblastoma patients. In patients with glioblastoma, MGMT promoter methylation in tumor tissue was not more predictive for response to alkylating chemotherapy in patients who received concomitant corticosteroids. PMID:24367102

  2. Mechanism of the extraction of nitric acid and water by organic solutions of tertiary alkyl-amines

    International Nuclear Information System (INIS)

    The micellar aggregation of tri-alkyl-ammonium nitrates in low polarity organic solvents has been verified by viscosity, conductivity and sedimentation velocity measurements. The aggregation depends upon the polarity of solvent, the length of the alkyl radicals and the organic concentration of the various constituents (tri-alkyl-ammonium nitrate, tri-alkyl-amine, nitric acid, water). The amine salification law has been established and the excess nitric acid and water solubilities in the organic solutions have been measured. Nitric acid and water are slightly more soluble in micellar organic solutions than in molecular organic solutions. A description of excess nitric acid containing tri-alkyl-ammonium nitrate solutions is proposed. (author)

  3. A mild and efficient procedure for the synthesis of ethers from various alkyl halides

    Directory of Open Access Journals (Sweden)

    Mosstafa Kazemi

    2013-10-01

    Full Text Available A simple, mild and practical procedure has been developed for the synthesis of symmetrical and unsymmetrical ethers by using DMSO, TBAI in the presence of K2CO3. We extended the utility of Potassium carbonate as an efficient base for the preparation of ethers. A wide range of alkyl aryl and dialkyl ethers are synthezied from treatment of aliphatic alcohols and phenols with various alkyl halides in the prescence of efficient base Potassium carbonate. Secondary alkyl halides were easily converted to corresponding ethers in releatively good yields . This is a mild, simple and practical procedure for the preparation of ethers in high yields and suitable times under mild condition.

  4. Molecular modeling of the inhibition mechanism of 1-(2-aminoethyl)-2-alkyl-imidazoline

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Jun [College of Physics Science and Technology, China University of Petroleum Dongying, Shandong 257061 (China)], E-mail: zhjupc@yahoo.com; Liu Jinxiang [College of Physics Science and Technology, China University of Petroleum Dongying, Shandong 257061 (China); Yu Weizhao [College of Petroleum Engineering, China University of Petroleum Qingdao, Shandong 266555 (China); Yan Youguo; You Long; Liu Linfa [College of Physics Science and Technology, China University of Petroleum Dongying, Shandong 257061 (China)

    2010-06-15

    Inhibition mechanism of five 1-(2-aminoethyl)-2-alkyl-imidazoline derivatives for carbon steel against CO2 corrosion was studied by molecular modeling. Molecular reactivity derived from quantum chemical calculation is insensitive to alkyl length. Inhibitor molecules can be adsorbed preferentially on metal surface with imidazoline ring attached on the surface. And with increase of alkyl length, interaction between inhibitor molecule and metal surface is enhanced to enable more stable adsorption of inhibitor molecules, which will form more compact self-assembly membrane with higher inhibition efficiency. The efficiency order of the inhibitors obtained by theoretical analysis was verified by experimental results.

  5. Liposomes containing alkylated methotrexate analogues for phospholipase A(2) mediated tumor targeted drug delivery

    DEFF Research Database (Denmark)

    Kaasgaard, Thomas; Andresen, Thomas Lars; Jensen, Simon Skøde;

    2009-01-01

    alpha-carboxylic acid. The cytotoxicity of the gamma-alkylated compound towards KATO III (IC50 = 55 nM) and HT-29 (IC50 = 400 nM) cell lines, Was unaffected by the alkylation, whereas the additional benzyl group on the alpha-carboxyl group made the Compound nontoxic. The gamma-derivative with promising......Two lipophilic methotrexate analogues have been synthesized and evaluated for cytotoxicity against KATO III and HT-29 human colon cancer cells. Both analogues contained a C-16-alkyl chain attached to the gamma-carboxylic acid and one of the analogues had an additional benzyl group attached to the...

  6. Quantitative Structure-Activity Relationships in the Lithium and Sodium Affinities of n-Alkyl Fluorides

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    B3LYP/6-31+g (d, p) method was used to calculate the lithium and sodium affinities of n-alkyl fluoride. These affinities were found to obey the Holmes relationship, i.e. they correlate linearly with the quotient n/(n+1), where n is the number of carbon atoms in the alkyl chain. From the correlation the limiting values of lithium and sodium affinities for very long alkyl chain were predicted to be -153.3 kJ/mol and -108.4 kJ/mol, respectively.

  7. Synthesis, antibacterial and antioxidant activities of new 1-alkyl-4-(1-alkyl-4-oxo-1,4-dihydroquinolin-2-yl)pyridinium bromides.

    Science.gov (United States)

    Kahriman, Nuran; Yaylı, Büşra; Aktaş, Ayça; Iskefiyeli, Zeynep; Beriş, Fatih Şaban; Yaylı, Nurettin

    2013-11-01

    New 1-alkyl-4-(1-alkyl-4-oxo-1,4-dihydroquinolin-2-yl)pyridinium bromides (3a-k) were synthesized from 1,4'-diazaflavone [2-pyridin-4-ylquinolin-4(1H)-one] and evaluated for antibacterial and antioxidant activities. A rapid one-pot preparation of 1,4'-diazaflavone (2) was done from 2'-amino substituted chalcone (1) by intramolecular Michael addition using solvent-free microwave heating. New N,N'-dialkyl substituted (C₅-C₁₅) 1,4'-diazaflavonium bromides were synthesized from compound 2 with corresponding alkyl halides. Compounds 3a-k were active against six bacteria (MIC: 7.8-500.0 μg/mL). They also showed good antioxidant activities in DPPH scavenging (SC₅₀: 45-133 μg/mL) and ferric reducing/antioxidant power (14-141 μM TEAC) tests. The biological activities decreased as alkyl chain length increased. The reason behind the obvious negative effect of alkyl chain elongation is unclear and requires investigations about the intermolecular interactions of these pyridinium salts with bioassay components. PMID:24077525

  8. Ultrasonic Relaxation Study of 1-Alkyl-3-methylimidazolium-Based Room-Temperature Ionic Liquids: Probing the Role of Alkyl Chain Length in the Cation.

    Science.gov (United States)

    Zorębski, Michał; Zorębski, Edward; Dzida, Marzena; Skowronek, Justyna; Jężak, Sylwia; Goodrich, Peter; Jacquemin, Johan

    2016-04-14

    Ultrasound absorption spectra of four 1-alkyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imides were determined as a function of the alkyl chain length on the cation from 1-propyl to 1-hexyl from 293.15 to 323.15 K at ambient pressure. Herein, the ultrasound absorption measurements were carried out using a standard pulse technique within a frequency range from 10 to 300 MHz. Additionally, the speed of sound, density, and viscosity have been measured. The presence of strong dissipative processes during the ultrasound wave propagation was found experimentally, i.e., relaxation processes in the megahertz range were observed for all compounds over the whole temperature range. The relaxation spectra (both relaxation amplitude and relaxation frequency) were shown to be dependent on the alkyl side chain length of the 1-alkyl-3-methylimidazolium ring. In most cases, a single-Debye model described the absorption spectra very well. However, a comparison of the determined spectra with the spectra of a few other imidazolium-based ionic liquids reported in the literature (in part recalculated in this work) shows that the complexity of the spectra increases rapidly with the elongation of the alkyl chain length on the cation. This complexity indicates that both the volume viscosity and the shear viscosity are involved in relaxation processes even in relatively low frequency ranges. As a consequence, the sound velocity dispersion is present at relatively low megahertz frequencies. PMID:26982480

  9. Current approaches to improve the anticancer chemotherapy with alkylating agents: state of the problem in world and Ukraine.

    Directory of Open Access Journals (Sweden)

    Iatsyshyna A. P.

    2012-01-01

    Full Text Available Alkylating agents are frequently used in many established anticancer chemotherapies. They alkylate the genomic DNA at various sites. Alkylation of the guanine at the O6-position is cytotoxic, it has the strongest mutagenic potential, as well as can cause the tumor development. Alkyl groups at the O6-position of guanine are removed by the DNA repair enzyme O6-methylguanine-DNA methyltransferase (MGMT. The effectiveness of alkylating chemotherapy is limited by MGMT in cancer cells and adverse toxic side effects in normal cells. Different approaches consisting in the modulation of the MGMT expression and activity are under development now to improve the cancer chemotherapy. They include two main directions, in particular, the increase in chemosensitivity of cancer cells to alkylating drugs and the protection of normal cells from the toxic side effects of chemotherapy. This review is focused on current attempts to improve the alkylating chemotherapy of malignant tumours worldwide and state of the issue in Ukraine

  10. Aromatic Structure in Simulates Titan Aerosol

    Science.gov (United States)

    Trainer, Melissa G.; Loeffler, M. J.; Anderson, C. M.; Hudson, R. L.; Samuelson, R. E.; Moore, M. A.

    2011-01-01

    Observations of Titan by the Cassini Composite Infrared Spectrometer (CIRS) between 560 and 20 per centimeter (approximately 18 to 500 micrometers) have been used to infer the vertical variations of Titan's ice abundances, as well as those of the aerosol from the surface to an altitude of 300 km [1]. The aerosol has a broad emission feature centered approximately at 140 per centimeter (71 micrometers). As seen in Figure 1, this feature cannot be reproduced using currently available optical constants from laboratory-generated Titan aerosol analogs [2]. The far-IR is uniquely qualified for investigating low-energy vibrational motions within the lattice structures of COITIDlex aerosol. The feature observed by CIRS is broad, and does not likely arise from individual molecules, but rather is representative of the skeletal movements of macromolecules. Since Cassini's arrival at Titan, benzene (C6H6) has been detected in the atmosphere at ppm levels as well as ions that may be polycyclic aromatic hydrocarbons (PAHs) [3]. We speculate that the feature may be a blended composite that can be identified with low-energy vibrations of two-dimensional lattice structures of large molecules, such as PAHs or nitrogenated aromatics. Such structures do not dominate the composition of analog materials generated from CH4 and N2 irradiation. We are performing studies forming aerosol analog via UV irradiation of aromatic precursors - specifically C6H6 - to understand how the unique chemical architecture of the products will influence the observable aerosol characteristics. The optical and chemical properties of the aromatic analog will be compared to those formed from CH4/N2 mixtures, with a focus on the as-yet unidentified far-IR absorbance feature. Preliminary results indicate that the photochemically-formed aromatic aerosol has distinct chemical composition, and may incorporate nitrogen either into the ring structure or adjoined chemical groups. These compositional differences are

  11. Structural description of aromatic core in residue fractions

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, H.C.; Sun, W.F.; Fang, X.C.; Guan, M.H. [Fushun Research Inst. of Petroleum and Petrochemicals, Fushun, Liaoning (China)

    2008-07-01

    The chemical structures of a polycyclic aromatic core in Oman residue fractions was examined using proton nuclear magnetic resonance spectroscopy (1H-NMR), synchronous fluorescence spectrometry (SFS) and ruthenium ions catalyzed oxidation (RICO). It was important to understand the aromatic core structure in heavy oil fractions, including aromatic rings system size and condensed type. The types and content of benzenepolycarboxylic acids disclosed the condensed types of aromatic rings in core. Biphenyl fraction (BIPH), cata-condensed fraction (CATA), peri-condensed fraction (PERI) and condensed index (BCI) were calculated by benzenepolycarboxylic acids. The results from 1H-NMR showed that about 3.2 aromatic rings were in the aromatics core, 5.6 rings were in the resins unit, and 8.2 rings were in the asphaltenes unit. This paper also described the aromatic rings distribution of residue fractions as determined by SFS. The type and content of benzenepolycarboxylic acids from RICO of residue fractions suggested the condensed mode of rings in the aromatic core. The most cata-condensed type aromatic structures were in aromatics, the whole peri-condensed type were in asphaltenes, while the dominant peri-condensed type, as well as some quantity of cata-condensed type structures existed together in resins. Aromatics, resins and asphaltenes were given likely structural models based on results from this study. 8 refs., 3 tabs., 7 figs.

  12. Radiation chemistry of aromatic dimer radical cations

    International Nuclear Information System (INIS)

    π-π Interactions of aromatic molecules are paid attention much in many fields, especially biology, chemistry, and applied physics, represented as protein, DNA, electron donor-accepter complexes, charge transfers, and self assembly molecules. Aromatic molecules including benzene rings are the simplest case to study the π-π interactions. To interpret the charge resonance (CR) structure in the dimer radical cations, spectroscopic and ESR methods have been carried out. The spectroscopic study on the dimer radical ion of molecules with two chromophores would be profitable to identify the electronic and configurational properties. In this article, dynamics of the dimer radical cation of benzenes, polystyrenes, and resist polymers is described on the basis of direct observation of CR band by the nanosecond pulse radiolysis and low temperature γ-radiolysis methods. (author)

  13. Starlike aluminum-carbon aromatic species.

    Science.gov (United States)

    Wu, Yan-Bo; Jiang, Jin-Liang; Lu, Hai-Gang; Wang, Zhi-Xiang; Perez-Peralta, Nancy; Islas, Rafael; Contreras, Maryel; Merino, Gabriel; Wu, Judy I-Chia; Schleyer, Paul von Ragué

    2011-01-10

    Is it possible to achieve molecules with starlike structures by replacing the H atoms in (CH)(n)(q) aromatic hydrocarbons with aluminum atoms in bridging positions? Although D(4h) C(4)Al(4)(2-) and D(2) C(6)Al(6) are not good prospects for experimental realization, a very extensive computational survey of fifty C(5)Al(5)(-) isomers identified the starlike D(5h) global minimum with five planar tetracoordinate carbon atoms to be a promising candidate for detection by photoelectron detachment spectroscopy. BOMD (Born-Oppenheimer molecular dynamics) simulations and high-level theoretical computations verified this conclusion. The combination of favorable electronic and geometric structural features (including aromaticity and optimum C-Al-C bridge bonding) stabilizes the C(5)Al(5)(-) star preferentially. PMID:21207593

  14. Synthesis of aromatic cytokinins for plant biotechnology.

    Science.gov (United States)

    Plíhalová, Lucie; Vylíčilová, Hana; Doležal, Karel; Zahajská, Lenka; Zatloukal, Marek; Strnad, Miroslav

    2016-09-25

    Cytokinins represent an important group of plant growth regulators that can modulate several biotechnological processes owing to their ability to influence almost all stages of plant development and growth. In addition, the use of purine based cytokinins with aromatic substituent in C6 position of the purine moiety in tissue culture techniques is currently experiencing a surge in interest, made possible by the ongoing systematic synthesis and study of these compounds. This review article outlines progress in the synthesis of aromatic cytokinins, the in vitro and in vivo effects of these substances and insights gleaned from their synthesis. As the purine moiety in these compounds can be substituted at several positions, we examine each of the substitution possibilities in relation to the derivatives prepared so far. The discussion highlights the gradual simplification of their preparation in relation to their application in practice and summarizes the relevant organic chemistry literature and published patents. PMID:26703810

  15. Occurrence, distribution and health risk from polycyclic aromatic compounds (PAHs, oxygenated-PAHs and azaarenes) in street dust from a major West African Metropolis.

    Science.gov (United States)

    Bandowe, Benjamin A Musa; Nkansah, Marian Asantewah

    2016-05-15

    Scientific evidence suggests that the burden of disease on urban residents of sub-Saharan African Countries is increasing, partly as a result of exposure to elevated concentrations of toxic environmental chemicals. However, characterization of the levels, composition pattern and sources of polycyclic aromatic compounds (PACs) in environmental samples from African cities is still lacking. This study measured the PAHs, oxygenated-PAHs (OPAHs) and azaarene (AZAs) content of street dusts collected from Kumasi, Ghana (a major metropolis located in the tropical forest zone of West Africa). The ∑Alkyl+parent-PAHs, ∑OPAHs and ∑AZAs concentration in street dust averaged 2570ngg(-1) (range: 181-7600ngg(-1)), 833ngg(-1) (57-4200ngg(-1)) and 73ngg(-1) (3.3-240ngg(-1)), respectively. The concentrations of ∑Alkyl+parent-PAHs were strongly correlated (n=25) with ∑OPAHs (r=0.96, psoils from same city, demonstrating the high influence of traffic emissions. Several individual OPAHs and AZAs had higher concentrations than their related and often monitored parent-PAHs. The estimated incremental lifetime cancer risks due to the parent-PAHs in street dusts was >10(-6) indicating high risk of contracting cancer from exposure to street dust from Kumasi. The contribution of OPAHs, AZAs, and alkyl-PAHs in street dust to cancer risk could not be quantified because of lack of toxicity equivalency factors for these compounds; however this could be significant because of their high concentration and known higher toxicity of some polar PACs and alkyl-PAHs than their related parent-PAHs. PMID:26930316

  16. Photochemical alkylation of inorganic selenium in the presence of low molecular weight organic acids.

    Science.gov (United States)

    Guo, Xuming; Sturgeon, Ralph E; Mester, Zoltán; Gardner, Graeme J

    2003-12-15

    Using a flow-through photochemical reactor and a low pressure mercury lamp as a UV source, alkyl selenium species are formed from inorganic selenium(IV) in the presence of low molecular weight organic acids (LMW acids). The volatile alkyl Se species were cryogenically trapped and identified by GC-MS and GC-ICP-MS. In the presence of formic, acetic, propionic and malonic acids, inorganic selenium(IV) is converted by UV irradiation to volatile selenium hydride and carbonyl, dimethylselenide and diethylselenide, respectively. Se(IV) was successfully removed from contaminated agricultural drainage waters (California, U.S.A.) using a batch photoreactor system Se. Photochemical alkylation may thus offer a promising means of converting toxic selenium salts, present in contaminated water, to less toxic dimethylselenide. The LMW acids and photochemical alkylation process may also be key to understanding the source of atmospheric selenium and are likely involved in its mobility in the natural anaerobic environment. PMID:14717175

  17. Vibrational Spectroscopic Study of Imidazolium Dicationic Ionic Liquids: Effect of Cation Alkyl Chain Length

    Science.gov (United States)

    Moumene, T.; Belarbi, E. H.; Haddad, B.; Villemin, D.; Abbas, O.; Khelifa, B.; Bresson, S.

    2016-05-01

    Two new dicationic ionic liquids were synthesized: bis-methyl imidazolium methylidene hexafluorophosphate [M(CH2)IM2 +][2PF 6 - ] and bis-methyl imidazolium propylidene hexafluorophosphate [M(CH2)3IM2 +][2PF 6 - ]. Their structures were identified by H, C, P, F NMR, FTIR/ATR, and FT-Raman spectroscopies in order to study the effect of cation alkyl chain length on vibration behaviors. Several changes were recorded, which were related to alkyl chain length. A frequency shift was observed in some modes while others remained insensitive. A greater number of peaks was found in the FTIR/ATR spectra and the FT-Raman spectra with increasing alkyl chain length, which indicated that chain length influences the N-C connection twisting. More peaks with strong intensity appeared for longer alkyl chain lengths.

  18. Efficient, intermolecular, oxidative radical alkylation of heteroaromatic systems under "tin-free" conditions.

    Science.gov (United States)

    Osornio, Yazmin M; Cruz-Almanza, Raymundo; Jiménez-Montaño, Vicente; Miranda, Luis D

    2003-09-21

    Novel and efficient radical alkylation of several heterocyclic systems including pyrroles, indoles, furan and thiophenes is described using xanthate based radical chemistry. The present methodology could be used to provide rapid access to various nonsteroidal antiinflammatory drugs. PMID:14518892

  19. 40 CFR 721.10126 - Alkyl amino substituted triazine amino substituted benezenesulfonic acid reaction product with...

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Alkyl amino substituted triazine amino... substituted triazine amino substituted benezenesulfonic acid reaction product with naphthalenesulfonato azo... substituted triazine amino substituted benezenesulfonic acid reaction product with naphthalenesulfonato...

  20. Alkyl nitrate distributions and seasonal variation over the Pacific Ocean during HIPPO

    Science.gov (United States)

    Atlas, E. L.; Smith, K.; Zhu, X.; Pope, L.; Lueb, R.; Hendershot, R.; Moore, F. L.; Miller, B. R.; Montzka, S. A.; Elkins, J. W.; Wofsy, S. C.

    2012-12-01

    Alkyl nitrates are produced in both the atmosphere and in the ocean by photochemical oxidation of organic precursors. Past studies have shown that low molecular weight alkyl nitrates, particularly methyl and ethyl nitrate, have high production rates and air-sea fluxes from equatorial ocean waters. In addition, high concentrations of these organic nitrates have been found in the atmosphere of the Southern Ocean. Measurements during the HIPPO campaign were able to characterize the tropospheric distribution of these alkyl nitrates over all seasons, and from virtually pole to pole over the Central Pacific Ocean. The measurements from HIPPO confirm the strong equatorial source and in addition show a strong asymmetry in methyl nitrate concentrations between hemispheres, with the Southern Hemisphere having consistently higher concentrations compared to the Northern Hemisphere. This presentation will discuss the alkyl nitrate distributions, sources, and variations observed during the HIPPO campaign and examine relationships to other trace gases of oceanic origin, such as DMS and methyl iodide.

  1. MULTISPECTRAL IDENTIFICATION OF ALKYL AND CHLOROALKYL PHOSPHATES FROM AN INDUSTRIAL EFFLUENT

    Science.gov (United States)

    Multispectral techniques (gas chromatography combined with low and high resolution electron-impact mass spectrometry, low and high resolution chemical ionization mass spectrometry, and Fourier transform infrared mass spectroscopy) were used to identify 13 alkyl and chloralkyl pho...

  2. Carcinogenic potential of hydrotreated petroleum aromatic extracts.

    OpenAIRE

    Doak, S. M.; Hend, R W; van der Wiel, A; Hunt, P F

    1985-01-01

    Five experimental petroleum extracts were produced from luboil distillates derived from Middle East paraffinic crude by solvent extraction and severe hydrotreatment. The polycyclic aromatic content (PCA) of the extracts was determined by dimethyl sulphoxide extraction and ranged from 3.7-9.2% w/w. The five extracts were evaluated for their potential to induce cutaneous and systemic neoplasia in female mice derived from Carworth Farm No 1 strain (CF1). The test substances were applied undilute...

  3. Aromatic compounds from three Brazilian Lauraceae species

    Energy Technology Data Exchange (ETDEWEB)

    Batista, Andrea Nastri de Luca; Batista Junior, Joao Marcos; Lopez, Silvia Noeli; Furlan, Maysa; Cavalheiro, Alberto Jose; Silva, Dulce Helena Siqueira; Bolzani, Vanderlan da Silva [UNESP, Araraquara, SP (Brazil). Inst. de Quimica. Dept. de Quimica Organica; Nunomura, Sergio Massayoshi [Instituto Nacional de Pesquisa da Amazonia (INPA), Manaus, AM (Brazil). Dept. de Produtos Naturais; Yoshida, Massayoshi [Centro de Biotecnologia da Amazonia, Manaus, AM (Brazil)

    2010-07-01

    Phytochemical investigations on three Brazilian Lauraceae species from the Cerrado region of Sao Paulo State, Ocotea corymbosa (Meins) Mez., O. elegans Mez. and Persea pyrifolia Nees and Mart. ex Nees resulted in the isolation of flavonoids, an ester of the 4-O-E-caffeoylquinic acid, an aromatic sesquiterpene besides furofuran lignans. This is the first chemical study on the leaves of Ocotea elegans and O. corymbosa as well as the first report of non-volatile compounds from Persea pyrifolia. (author)

  4. Aromatic compounds from three Brazilian Lauraceae species

    International Nuclear Information System (INIS)

    Phytochemical investigations on three Brazilian Lauraceae species from the Cerrado region of Sao Paulo State, Ocotea corymbosa (Meins) Mez., O. elegans Mez. and Persea pyrifolia Nees and Mart. ex Nees resulted in the isolation of flavonoids, an ester of the 4-O-E-caffeoylquinic acid, an aromatic sesquiterpene besides furofuran lignans. This is the first chemical study on the leaves of Ocotea elegans and O. corymbosa as well as the first report of non-volatile compounds from Persea pyrifolia. (author)

  5. Decarboxylative and direct functionalisations of aromatic compounds

    OpenAIRE

    Seo, Sangwon

    2014-01-01

    Aromatic rings are privileged structures found in a diverse range of natural and synthetic compounds, thus synthetic methods for their functionalisations are important in organic synthesis. Despite significant advancements made, especially in the field of transition metal catalysis, work still continues for the development of milder, more efficient, and more atom economical reactions. We describe here our efforts towards the development of decarboxylative/direct C(aryl)–N and C(aryl)–C bond f...

  6. AN AROMATIC COMPOUND from CENTAUREA PTOSIMOPAPPOIDES

    OpenAIRE

    A. ULUBELEN, S. ÖKSÜZ

    2015-01-01

    Centaurea ptosimopappoides was previously investigated by our groupand the presence of two new triterpenes were reported. The rare occurrence ofthis type compounds in the plants prompted us to further investigation of Centaureaptosimopappoides. In this work we report the isolation and structure determinationof an aromatic glycoside which was found in the genus Centaureafor the first time. The structure of the compound was determined by spectralmethods.Key words: Centaurea ptosimopappoides; Co...

  7. Synthetic fuel aromaticity and staged combustion

    Energy Technology Data Exchange (ETDEWEB)

    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.

  8. ANTIEMETIC ACTIVITY OF SOME AROMATIC PLANTS

    OpenAIRE

    Hasan MuhammadMohtasheemul; Ahmed Salman; Ahmed Ziauddin; Azhar Iqbal

    2012-01-01

    Current study was conducted to explore the antiemetic activity of ten aromatic medicinal plants viz., Carissa carandus L. (fruits), Chichorium intybus L (flowers), Cinnamum tamala L (leaves), Curcuma caesia Roxb (rhizomes), Lallemantia royleana Benth (leaves), Matricaria chamomila L (flowers), Piper longum L (fruits), Piper methysticum G. Forst (fruits), Piper nigrum Linn. (fruits) and Syzygium aromaticum (Linn.) Merr. & Perry (flowering buds) was studied using chick emetic model. The ethan...

  9. Spectroscopic Characterisation of Novel Polycyclic Aromatic Polymers

    OpenAIRE

    O'Neill, Luke; Lynch, Patrick; McNamara, Mary; Byrne, Hugh

    2007-01-01

    A series of novel polyphenylenevinylene (PPV) derivative polymers were studied by absorption and photoluminescence spectroscopies. The effect of the sequential introduction of polycyclic aromatic ring substituents into the delocalized backbone was examined with relation to hypsochromatic and bathochromatic shifting. While the replacement of the phenyl units by naphthyl units results in a substantial hypsochromic shift of both the absorption and emission spectra, their subsequent substitution ...

  10. Characterization of two alkyl hydroperoxide reductase C homologs alkyl hydroperoxide reductase C_H1 and alkyl hydroperoxide reductase C_H2 in Bacillus subtilis

    Institute of Scientific and Technical Information of China (English)

    Mee-Kyung; Cha; Yoo-Jeen; Bae; Kyu-Jeong; Kim; Byung-Joon; Park; Il-Han; Kim

    2015-01-01

    AIM: To identify alkyl hydroperoxide reductase subunit C(AhpC) homologs in Bacillus subtilis(B. subtilis) and to characterize their structural and biochemical properties. AhpC is responsible for the detoxification of reactive oxygen species in bacteria.METHODS: Two AhpC homologs(AhpC_H1 and AhpC_H2) were identified by searching the B. subtilis database; these were then cloned and expressed in Escherichia coli. AhpC mutants carrying substitutions of catalytically important Cys residues(C37S, C47 S, C166 S, C37/47 S, C37/166 S, C47/166 S, and C37/47/166 S for AhpC_H1; C52 S, C169 S, and C52/169 S for AhpC_H2) were obtained by site-directed mutagenesis and purified, and their structure-function relationship was analyzed. The B. subtilis ahp C genes were disrupted by the short flanking homology method, and the phenotypes of the resulting AhpC-deficient bacteria were examined.RESULTS: Comparative characterization of AhpC homologs indicates that AhpC_H1 contains an extra C37, which forms a disulfide bond with the peroxidatic C47, and behaves like an atypical 2-Cys AhpC, while AhpC_H2 functions like a typical 2-Cys AhpC. Tryptic digestion analysis demonstrated the presence of intramolecular Cys37-Cys47 linkage, which could be reduced by thioredoxin, resulting in the association of the dimer into higher-molecular-mass complexes. Peroxidase activity analysis of Cys→Ser mutants indicated that three Cys residues were involved in the catalysis. AhpC_H1 was resistant to inactivation by peroxide substrates, but had lower activity at physiological H2O2 concentrations compared to AhpC_H2, suggesting that in B. subtilis, the enzymes may be physiologically functional at different substrate concentrations. The exposure to organic peroxides induced AhpC_H1 expression, while AhpC_H1-deficient mutants exhibited growth retardation in the stationary phase, suggesting the role of AhpC_H1 as an antioxidant scavenger of lipid hydroperoxides and a stress-response factor in B. subtilis

  11. Aromatics Oxidation and Soot Formation in Flames

    Energy Technology Data Exchange (ETDEWEB)

    Howard, J. B.; Richter, H.

    2005-03-29

    This project is concerned with the kinetics and mechanisms of aromatics oxidation and the growth process to polycyclic aromatic hydrocarbons (PAH) of increasing size, soot and fullerenes formation in flames. The overall objective of the experimental aromatics oxidation work is to extend the set of available data by measuring concentration profiles for decomposition intermediates such as phenyl, cyclopentadienyl, phenoxy or indenyl radicals which could not be measured with molecular-beam mass spectrometry to permit further refinement and testing of benzene oxidation mechanisms. The focus includes PAH radicals which are thought to play a major role in the soot formation process while their concentrations are in many cases too low to permit measurement with conventional mass spectrometry. The radical species measurements are used in critical testing and improvement of a kinetic model describing benzene oxidation and PAH growth. Thermodynamic property data of selected species are determined computationally, for instance using density functional theory (DFT). Potential energy surfaces are explored in order to identify additional reaction pathways. The ultimate goal is to understand the conversion of high molecular weight compounds to nascent soot particles, to assess the roles of planar and curved PAH and relationships between soot and fullerenes formation. The specific aims are to characterize both the high molecular weight compounds involved in the nucleation of soot particles and the structure of soot including internal nanoscale features indicative of contributions of planar and/or curved PAH to particle inception.

  12. Two-dimensional inorganic–organic hybrid semiconductors composed of double-layered ZnS and monoamines with aromatic and heterocyclic aliphatic rings: Syntheses, structures, and properties

    International Nuclear Information System (INIS)

    As an addition to the II–VI based inorganic–organic hybrid semiconductor family, five new two-dimensional (2D) double-layered structures have been synthesized employing monoamines with different aromatic or heterocyclic aliphatic rings. Zn2S2(bza) (1), Zn2S2(mbza) (2), Zn2S2(fbza) (3), Zn2S2(pca) (4), and Zn2S2(thfa) (5) (bza=benzylamine, mbza=4-methoxybenzylamine, fbza=4-flurobenzylamine, pca=3-picolylamine, and thfa=tetrahydrofurfurylamine) are prepared by solvothermal reactions and characterized by different analytical methods, including powder X-ray diffraction, optical diffuse reflection, thermogravimetric analysis and photoluminescence spectroscopy. The powder X-ray diffraction patterns show that all five compounds adopt 2D double-layered structures. Optical diffuse reflectance spectra of these compounds suggest that they have notably lower band gaps than those of the similar compounds composed of aliphatic alkyl amines. Their photoluminescence properties and thermal stability are also analyzed. - Graphical abstract: Five new members of two-dimensional double-layered 2D-Zn2S2(L) (L=Ligand) structures employing monoamines with different aromatic or heterocyclic aliphatic rings have been designed, synthesized, and characterized. - Highlights: • A new sub-family of II-VI based hybrid semiconductors are designed, synthesized, and structurally characterized using amines with aromatic or aliphatic cyclic rings. • These compounds have notably lower band gaps than those made of aliphatic alkyl amines, greatly broadening the range of band gaps of this material family. • They emit strongly with systematically tunable emission intensity and energy

  13. Synthesis of N-Alkyl-2-thiomethyl Benzimidazoles: A Green Approach

    OpenAIRE

    S. Srinivas Rao; Ch. Venkata Ramana Reddy; Dubey, P.K.

    2014-01-01

    A green approach for the synthesis of N-alkyl-2-thiomethyl benzimidazoles 2 (R=CH3, C2H5, CH2Ph) under different conditions has been developed from N-alkyl-2-chloromethyl benzimidazole (i.e., CH3, C2H5, CH2Ph) 1 by reaction with thiourea by physical grinding, or by using green solvents like ethanol and PEG-600, or by using microwave irradiation technique.

  14. Risk factors for oral mucositis in paediatric oncology patients receiving alkylant chemotherapy

    OpenAIRE

    Fadda, Giulia; Campus, Guglielmo; Lugliè, PierFranca

    2006-01-01

    Background We describe the risk indicators for oral mucositis (OM) in paediatric oncology patients hospitalised in the Institut Gustave Roussy (Villejuif-Paris) and treated with alkylant chemotherapy with autologous peripheral blood progenitor cells. Methods The sample was selected using PIGAS software. Three groups of subjects received different chemotherapy regimens: A. Melphalan, B. Busulfan and C. other alkylant protocols. The degree of mucositis was recorded by CTC version 2.0 (Common To...

  15. Risk factors for oral mucositis in paediatric oncology patients receiving alkylant chemotherapy

    OpenAIRE

    Campus Guglielmo; Fadda Giulia; Lugliè PierFranca

    2006-01-01

    Abstract Background We describe the risk indicators for oral mucositis (OM) in paediatric oncology patients hospitalised in the Institut Gustave Roussy (Villejuif-Paris) and treated with alkylant chemotherapy with autologous peripheral blood progenitor cells. Methods The sample was selected using PIGAS software. Three groups of subjects received different chemotherapy regimens: A. Melphalan, B. Busulfan and C. other alkylant protocols. The degree of mucositis was recorded by CTC version 2.0 (...

  16. Risk factors for oral mucositis in paediatric oncology patients receiving alkylant chemotherapy

    OpenAIRE

    Fadda, Giulia; Campus, Guglielmo Giuseppe; Lugliè, Pietrina Francesca

    2006-01-01

    Background: We describe the risk indicators for oral mucositis (OM) in paediatric oncology patients hospitalised in the Institut Gustave Roussy (Villejuif-Paris) and treated with alkylant chemotherapy with autologous peripheral blood progenitor cells. Methods: The sample was selected using PIGAS software. Three groups of subjects received different chemotherapy regimens: A. Melphalan, B. Busulfan and C. other alkylant protocols. The degree of mucositis was recorded by CTC versi...

  17. Alkylation and Carbamylation Effects of Lomustine and Its Major Metabolites and MGMT Expression in Canine Cells

    OpenAIRE

    Thushara Chakkath; Sidonie Lavergne; Fan, Timothy M.; David Bunick; Levent Dirikolu

    2015-01-01

    DNA Alkylation is thought to be the reason for the efficacy of lomustine while carbamylation has been implicated as the cause for the side effects seen with lomustine treatment such as hepatotoxicity. In the alkylation study we show that lomustine and its metabolites form similar levels of the DNA adducts N7 hydroxyethylguanine and O6 hydroxyethyldeoxyguanosine. In terms of carbamylation, lomustine showed greater extent of carbamylation in the canine hepatocytes and lymphoma cell lines. The ...

  18. Alkyl Caffeates Improve the Antioxidant Activity, Antitumor Property and Oxidation Stability of Edible Oil

    OpenAIRE

    Wang, Jun; Gu, Shuang-Shuang; Pang, Na; Wang, Fang-Qin; Pang, Fei; Cui, Hong-Sheng; Wu, Xiang-Yang; Wu, Fu-An

    2014-01-01

    Caffeic acid (CA) is distributed widely in nature and possesses strong antioxidant activity. However, CA has lower solubility in non-polar media, which limits its application in fat-soluble food. To increase the lipophilicity of natural antioxidant CA, a series of alkyl caffeates were synthesized and their antioxidant and antitumor activities were investigated. The antioxidant parameters, including the induction period, acid value and unsaturated fatty acid content, of the alkyl caffeates in ...

  19. Dependence of micelle size and shape on detergent alkyl chain length and head group.

    Directory of Open Access Journals (Sweden)

    Ryan C Oliver

    Full Text Available Micelle-forming detergents provide an amphipathic environment that can mimic lipid bilayers and are important tools for solubilizing membrane proteins for functional and structural investigations in vitro. However, the formation of a soluble protein-detergent complex (PDC currently relies on empirical screening of detergents, and a stable and functional PDC is often not obtained. To provide a foundation for systematic comparisons between the properties of the detergent micelle and the resulting PDC, a comprehensive set of detergents commonly used for membrane protein studies are systematically investigated. Using small-angle X-ray scattering (SAXS, micelle shapes and sizes are determined for phosphocholines with 10, 12, and 14 alkyl carbons, glucosides with 8, 9, and 10 alkyl carbons, maltosides with 8, 10, and 12 alkyl carbons, and lysophosphatidyl glycerols with 14 and 16 alkyl carbons. The SAXS profiles are well described by two-component ellipsoid models, with an electron rich outer shell corresponding to the detergent head groups and a less electron dense hydrophobic core composed of the alkyl chains. The minor axis of the elliptical micelle core from these models is constrained by the length of the alkyl chain, and increases by 1.2-1.5 Å per carbon addition to the alkyl chain. The major elliptical axis also increases with chain length; however, the ellipticity remains approximately constant for each detergent series. In addition, the aggregation number of these detergents increases by ∼16 monomers per micelle for each alkyl carbon added. The data provide a comprehensive view of the determinants of micelle shape and size and provide a baseline for correlating micelle properties with protein-detergent interactions.

  20. Extraction of scandium ions by 1-alkyl-3-methyl-2-pyrazoline-5-ones from perchlorate solutions

    International Nuclear Information System (INIS)

    Extraction of acid and interphase distribution of 1-alkyl-3-methyl-2-pyrazoline-5-ones in the system water-chloroform-perchloric acid are studied. Reagents capable to extract scandium cations from subacid solutions in the presence of perchlorate ions. 1-Alkyl-3-methyl-2-pyrazoline-5-ones stratifies aqueous solutions of perchloric acid into two liquid phase. Scandium ions are concentrated in the lower phase having small volume

  1. A New Family of Ionic Liquids 1-amino-3-alkyl-1,2,3-Triazolium Nitrates

    Science.gov (United States)

    Drake, Greg; Kaplan, Greg; Hall, Leslie; Hawkins, Tommy; Larue, Joann

    2004-01-01

    A new class of ionic liquids based upon 1-amino-3-alkyl-1,2,3-triazolium nitrates (alkyl = methyl, ethyl, n-propyl, 2-propeny1, and n-butyl) have been synthesized and characterized by vibrational spectra, multinuclear NMR, elemental analysis, and DSC studies. A single crystal x-ray study was carried out for 1-amino-3-methyl-1,2,3-triazolium nitrate and the details will be presented.

  2. 2-Alkyl-4-aryl-pyrimidine fused heterocycles as selective 5-HT2A antagonists.

    Science.gov (United States)

    Shireman, Brock T; Dvorak, Curt A; Rudolph, Dale A; Bonaventure, Pascal; Nepomuceno, Diane; Dvorak, Lisa; Miller, Kirsten L; Lovenberg, Timothy W; Carruthers, Nicholas I

    2008-03-15

    The synthesis and SAR for a novel series of 2-alkyl-4-aryl-tetrahydro-pyrido-pyrimidines and 2-alkyl-4-aryl-tetrahydro-pyrimido-azepines is described. Representative compounds were shown to be subtype selective 5-HT(2A) antagonists. Optimal placement of a basic nitrogen relative to the pyrimidine and the presence of a 4-fluorophenyl group in the pyrimidine 4-position was found to have a profound effect on affinity and selectivity. PMID:18282705

  3. mTOR target NDRG1 confers MGMT-dependent resistance to alkylating chemotherapy

    OpenAIRE

    Weiler, M.; Blaes, J; Pusch, S.; Sahm, F; Czabanka, M; Luger, S; Bunse, L; Solecki, G; Eichwald, V; Jugold, M; Hodecker, S; Osswald, M; Meisner, C; Hielscher, T; Rübmann, P

    2014-01-01

    A hypoxic microenvironment induces resistance to alkylating agents by activating targets in the mammalian target of rapamycin (mTOR) pathway. The molecular mechanisms involved in this mTOR-mediated hypoxia-induced chemoresistance, however, are unclear. Here we identify the mTOR target N-myc downstream regulated gene 1 (NDRG1) as a key determinant of resistance toward alkylating chemotherapy, driven by hypoxia but also by therapeutic measures such as irradiation, corticosteroids, and chronic e...

  4. Multifunctional poly(alkyl methacrylate) films for dental care

    Energy Technology Data Exchange (ETDEWEB)

    Nielsen, Birthe V; Nevell, Thomas G; Barbu, Eugen; Smith, James R; Tsibouklis, John [School of Pharmacy and Biomedical Sciences, University of Portsmouth, Portsmouth, Hampshire, PO1 2DT (United Kingdom); Rees, Gareth D [GlaxoSmithKline R and D, St George' s Avenue, Weybridge, Surrey, KT13 0DE (United Kingdom)

    2011-02-15

    Towards the evaluation of non-permanent dental coatings for their capacity to impart dental-care benefits, thin films of a homologous series of comb-like poly(alkyl methacrylate)s (ethyl to octadecyl) have been deposited, from aqueous latex formulations, onto dentally relevant substrates. AFM studies have shown that the thickness (40-300 nm) and surface roughness (8-12 nm) of coherent polymer films are influenced by the degree of polymerization and by the length of the pendant chain. Of the polymers under consideration, poly(butyl methacrylate) formed a close-packed film that conferred to dental substrates a high degree of inhibition to acid-mediated erosion (about 27%), as evaluated by released-phosphate determinations. The potential utility of the coatings to act as anti-sensitivity barriers has been evaluated by determining the hydraulic conductance of coated bovine-dentine substrates; single treatments of dentine discs with poly(butyl methacrylate) or with poly(ethyl methacrylate) effected mean respective reductions in fluid flow of about 23% with respect to water-treated controls; repeated applications of the poly(butyl methacrylate) latex led to mean reductions in fluid flow of about 80%. Chromometric measurements have shown that pellicle-coated hydroxyapatite discs treated with poly(butyl methacrylate), poly(hexyl methacrylate) or poly(lauryl methacrylate) exhibit significant resistance to staining by food chromogens.

  5. Superhydrophobic terpolymer nanofibers containing perfluoroethyl alkyl methacrylate by electrospinning

    Energy Technology Data Exchange (ETDEWEB)

    Cengiz, Ugur, E-mail: ucengiz@gyte.edu.tr [Department of Chemical Engineering, Gebze Institute of Technology, Cayirova, 41400 Kocaeli (Turkey); Avci, Merih Z. [Polymer Science and Technology, Deparment of Chemistry, Istanbul Technical University, Maslak 34469, Istanbul (Turkey); Erbil, H. Yildirim [Department of Chemical Engineering, Gebze Institute of Technology, Cayirova, 41400 Kocaeli (Turkey); Sarac, A. Sezai [Polymer Science and Technology, Deparment of Chemistry, Istanbul Technical University, Maslak 34469, Istanbul (Turkey)

    2012-05-15

    A new statistical terpolymer containing perfluoroethyl alkyl methacrylate (Zonyl-TM), methyl methacrylate and butyl acrylate, poly(Zonyl-TM-ran-MMA-ran-BA) was synthesized in supercritical carbon dioxide at 200 bar and 80 Degree-Sign C using AIBN as an initiator by heterogeneous free radical copolymerization. Nanofibers of this terpolymer were produced by electrospinning from its DMF solution. The structural and thermal properties of terpolymers and electrospun poly(Zonyl-TM-MMA-BA) nanofibers were analyzed using Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy and differential scanning calorimetry. Nanofiber morphology was investigated by scanning electron microscopy. Electrospun nanofiber layer was found to be superhydrophobic with a water contact angle of 172 {+-} 1 Degree-Sign and highly oleophobic with hexadecane, glycerol and ethylene glycol contact angles of 70 {+-} 1 Degree-Sign , 167 {+-} 1 Degree-Sign and 163 {+-} 1 Degree-Sign respectively. The change of the contact angle results on the electrospun fiber layer and flat terpolymer surfaces by varying feed monomer composition were compared and discussed in the text.

  6. Modeling of alkyl quaternary ammonium cations intercalated into montmorillonite lattice

    International Nuclear Information System (INIS)

    Highlights: ► The modification of montmorillonites by three surfactants increases the basal spacing. ► The model proposed show a bilayer conformation for the surfactant ODTMA. ► The DODMA and TOMA surfactants adopt a paraffin type arrangement. ► Behavior of surfactants in interlayer space was confirmed by TGA and ATR analysis. - Abstract: The objective of this work was to study the conformation of the quaternary ammonium cations viz., octadecyl trimethyl ammonium (ODTMA), dioctadecyl dimethyl ammonium (DMDOA) and trioctadecyl methyl ammonium (TOMA) intercalated within montmorillonite. The modified montmorillonite was characterized by X-ray diffraction in small angle (SAXS), thermal analysis (TGA) and infrared spectroscopy of attenuated total reflection (ATR). The modification of organophilic montmorillonites by the three surfactants ODTMA, DMDOA and TOMA increases the basal spacing from their respective intercalated distances of 1.9 nm, 2.6 nm and 3.4 nm respectively. The increase in the spacing due to the basic organic modification was confirmed by the results of thermal analysis (TGA) and infrared spectroscopy (ATR), and also supported by theoretical calculations of longitudinal and transversal chain sizes of these alkyl quaternary ammonium cations

  7. Superhydrophobic terpolymer nanofibers containing perfluoroethyl alkyl methacrylate by electrospinning

    International Nuclear Information System (INIS)

    A new statistical terpolymer containing perfluoroethyl alkyl methacrylate (Zonyl-TM), methyl methacrylate and butyl acrylate, poly(Zonyl-TM-ran-MMA-ran-BA) was synthesized in supercritical carbon dioxide at 200 bar and 80 °C using AIBN as an initiator by heterogeneous free radical copolymerization. Nanofibers of this terpolymer were produced by electrospinning from its DMF solution. The structural and thermal properties of terpolymers and electrospun poly(Zonyl-TM-MMA-BA) nanofibers were analyzed using Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy and differential scanning calorimetry. Nanofiber morphology was investigated by scanning electron microscopy. Electrospun nanofiber layer was found to be superhydrophobic with a water contact angle of 172 ± 1° and highly oleophobic with hexadecane, glycerol and ethylene glycol contact angles of 70 ± 1°, 167 ± 1° and 163 ± 1° respectively. The change of the contact angle results on the electrospun fiber layer and flat terpolymer surfaces by varying feed monomer composition were compared and discussed in the text.

  8. Alkyl hydroperoxide reductase: a candidate Helicobacter pylori vaccine.

    Science.gov (United States)

    O'Riordan, Avril A; Morales, Veronica Athie; Mulligan, Linda; Faheem, Nazia; Windle, Henry J; Kelleher, Dermot P

    2012-06-01

    Helicobacter pylori (H. pylori) is the most important etiological agent of chronic active gastritis, peptic ulcer disease and gastric cancer. The aim of this study was to evaluate the efficacy of alkyl hydroperoxide reductase (AhpC) and mannosylated AhpC (mAhpC) as candidate vaccines in the C57BL/6J mouse model of H. pylori infection. Recombinant AhpC was cloned, over-expressed and purified in an unmodified form and was also engineered to incorporate N and C-terminal mannose residues when expressed in the yeast Pichia pastoris. Mice were immunized systemically and mucosally with AhpC and systemically with mAhpC prior to challenge with H. pylori. Serum IgG responses to AhpC were determined and quantitative culture was used to determine the efficacy of vaccination strategies. Systemic prophylactic immunization with AhpC/alum and mAhpC/alum conferred protection against infection in 55% and 77.3% of mice, respectively. Mucosal immunization with AhpC/cholera toxin did not protect against infection and elicited low levels of serum IgG in comparison with systemic immunization. These data support the use of AhpC as a potential vaccine candidate against H. pylori infection. PMID:22512976

  9. Effects of alkyl polyglycoside (APG) on composting of agricultural wastes

    International Nuclear Information System (INIS)

    Composting is the biological degradation and transformation of organic materials under controlled conditions to promote aerobic decomposition. To find effective ways to accelerate composting and improve compost quality, numerous methods including additive addition, inoculation of microorganisms, and the use of biosurfactants have been explored. Studies have shown that biosurfactant addition provides more favorable conditions for microorganism growth, thereby accelerating the composting process. However, biosurfactants have limited applications because they are expensive and their use in composting and microbial fertilizers is prohibited. Meanwhile, alkyl polyglycoside (APG) is considered a 'green' surfactant. This study aims to determine whether APG addition into a compost reaction vessel during 28-day composting can enhance the organic matter degradation and composting process of dairy manure. Samples were periodically taken from different reactor depths at 0, 3, 5, 7, 14, 21, and 28 days. pH levels, electrical conductivity (EC), ammonium and nitrate nitrogen, seed germination indices, and microbial population were determined. Organic matter and total nitrogen were also measured. Compared with the untreated control, the sample with APG exhibited slightly increased microbial populations, such as bacteria, fungi, and actinomycetes. APG addition increased temperatures without substantially affecting compost pH and EC throughout the process. After 28 days, APG addition increased nitrate nitrogen concentrations, promoted matter degradation, and increased seed germination indices. The results of this study suggest that the addition of APG provides more favorable conditions for microorganism growth, slightly enhancing organic matter decomposition and accelerating the composting process, improving the compost quality to a certain extent.

  10. Breastfeeding as an Exposure Pathway for Perfluorinated Alkylates.

    Science.gov (United States)

    Mogensen, Ulla B; Grandjean, Philippe; Nielsen, Flemming; Weihe, Pal; Budtz-Jørgensen, Esben

    2015-09-01

    Perfluorinated alkylate substances (PFASs) are widely used and have resulted in human exposures worldwide. PFASs occur in breast milk, and the duration of breastfeeding is associated with serum-PFAS concentrations in children. To determine the time-dependent impact of this exposure pathway, we examined the serum concentrations of five major PFASs in a Faroese birth cohort at birth, and at ages 11, 18, and 60 months. Information about the children's breastfeeding history was obtained from the mothers. The trajectory of serum-PFAS concentrations during months with and without breastfeeding was examined by linear mixed models that accounted for the correlations of the PFAS measurements for each child. The models were adjusted for confounders such as body size. The duration of exclusive breastfeeding was associated with increases of most PFAS concentrations by up to 30% per month, with lower increases during partial breast-feeding. In contrast to this main pattern, perfluorohexanesulfonate was not affected by breast-feeding. After cessation of breastfeeding, all serum concentrations decreased. This finding supports the evidence of breastfeeding being an important exposure pathway to some PFASs in infants. PMID:26291735

  11. Role of clay as catalyst in Friedel–Craft alkylation

    Indian Academy of Sciences (India)

    Tanushree Choudhury; Nirendra M Misra

    2011-10-01

    Solid acids have become increasingly important for many liquid-phase industrial reactions these days. Montmorillonite clays (2:1 clay mineral) have been used as efficient solid acid catalysts for a number of organic and liquid phase reactions and offer several advantages over classic acids. Tailor made catalysts can be prepared from clays by suitably adjusting their acidity and surface area by acid activation. In the present work, preparation, characterization and performance of Pt (II) clays, Cu (II) clays, acid clay, and sol–gel hybrids of Cu (II) clays as solid catalysts in a test Friedel–Craft alkylation reaction of benzyl chloride with toluene using differential scanning calorimeter (DSC) are reported. Product formation has been analysed by FTIR spectroscopy. The main objective of this work is to show how clay as a solid catalyst affects reaction rates and activation energies. Acidity and dispersion of solid catalysts are twomain factors which govern a catalysis reaction. Kinetic parameter analysis and XRD studies confirm that acid Pt (II) clay and Pt (II) clay dispersed by natural dispersants aremore effective catalysts. In contrast to the reactions using AlCl3, the experimental conditions are non-polluting and the final work up does not require any aqueous treatment.

  12. Thiolate alkylation in tripod zinc complexes: a comparative kinetic study.

    Science.gov (United States)

    Rombach, Michael; Seebacher, Jan; Ji, Mian; Zhang, Guofang; He, Guosen; Ibrahim, Mohamed M; Benkmil, Boumahdi; Vahrenkamp, Heinrich

    2006-05-29

    The biologically relevant alkylations of the thiolate ligands in tripod zinc thiolates by methyl iodide were studied kinetically. Five tripod ligands of the pyrazolyl/thioimidazolyl borate type were employed, offering N3, N2S, NS2, and S3 donor sets. For each of them, the ethyl-, benzyl-, phenyl-, and p-nitrophenylthiolate zinc complexes were investigated, yielding a total of 20 second-order rate constants. The comparison of these rate constants shows three effects: (1) the electronic effect among the thiolates, i.e., the ethanethiolates react about 3 orders of magnitude faster than the p-nitrophenylthiolates; (2) the steric effect among the pyrazolylborates, i.e., the phenyl-substituted ones react about 2 orders of magnitude faster than the tert-butyl-substituted ones; and (3) the strong acceleration by the sulfur donors in the tripods, reaching 4 orders of magnitude between the reaction times of the (N3)Zn-SR and (S3)Zn-SR complexes. PMID:16711708

  13. Electrophilic Metal Alkyl Chemistry in New Ligand Environments

    Energy Technology Data Exchange (ETDEWEB)

    Jordan, Richard F. [University of Chicago

    2013-06-30

    The goals of this project were to design new electrophilic metal alkyl complexes and to exploit these systems in fundamental studies of olefin polymerization and other important and new catalytic reactions. A key target reaction is insertion copolymerization of olefins and polar CH2=CHX vinyl monomers such as vinyl halides and vinyl ethers. During the period covered by this report we (i) investigated the properties of ortho-alkoxy-arylphosphine ligands in Ni-based olefin polymerization catalysts, (ii) studied the synthesis of double-end-capped polyethylene using group 4 metal catalysts that contain tris-pyrazolylborate ligands, (iii) explored the ethylene insertion reactivity of group 4 metal tris-pyrazolyl-borate complexes, (iv) showed that (α-diimine)PdMe{sup +} species undergo multiple insertion of silyl vinyl ethers, (v) synthesized and explored the reactivity of base-free Ni benzyl complexes that contain ortho-phosphino-arene sulfonate ligands, (vi) established the mechanism of the reaction of vinyl chloride with (α-diimine)PdMe{sup +} catalysts, (vii) explored the role of cationic polymerization and insertion chemistry in the reactions of vinyl ethers with (α-diimine)PdMe{sup +} species, (viii) discovered a new class of self-assembled tetranuclear Pd catalysts that produce high molecular weight linear polyethylene and copolymerize ethylene and vinyl fluoride, and (ix) developed model systems that enabled investigation of cis-trans isomerization of {phosphine-sulfonate}Pd(II) complexes.

  14. Middle-phase microemulsions of green surfactant alkyl polyglucosides

    Institute of Scientific and Technical Information of China (English)

    CHAI; Jinling; (柴金岭); LI; Ganzuo; (李干佐); ZHANG; Gaoyong; (张高勇); LOU; Anjing; ZHANG; Jian; (张剑); ZHANG; Yue; (张越)

    2003-01-01

    The microemulsion behavior in the quaternary system alkyl polyglucoside (C8G1.46 , C10G1.54)/1-butanol/cyclohexane/water has been studied at 40℃ with the alcohol concentration scanning and the fishlike phase diagram methods. Increasing δat a constant γ causes a phase inversion from an oil-in-water microemulsion in contact with excess oil (Winsor I or 2 ) to a water-in-oil microemulsion in contact with excess water (Winsor Ⅲ or ) via a middle-phase microemulsionin contact with excess oil and water (Winsor Ⅲ or 3). By using the simple mass balance equation and the HLB plane equation, the mass fraction of 1-butanol in the interfacial layer, S s2, the monomeric solubilities of APG and 1-butanol, S1 and S2, in the oil phase, and the mass fractions of APG and 1-butanol in the interfacial layer (C1 and C2 ) have been calculated, respectively. The effects of different alcohols, aqueous media and oils on the phase behavior and the composition of the interfacial layer are also investigated. It is found that the alcohols with longer hydrocarbon chain, oil molecules with smaller molecular volume and the addition of inorganic salt can increase the solubilization of the microemulsions .

  15. UV absorption spectra, kinetics and mechanism for alkyl and alkyl peroxy radicals originating from t-butyl alcohol

    DEFF Research Database (Denmark)

    Langer, S.; Ljungström, E.; Sehested, J.;

    1994-01-01

    the self-reaction of HOC(CH3)2CH2. and HOC(CH3)2CH2O2. radicals were found to be (3.0 +/ -0.5) x 10(-11) and (7.8 +/- 1.5) X 10(-12) cm3 molecule-1 s-1, respectively. For the reaction of the alkyl radical with O2 in 1 atm SF6 a rate constant of (1.8 +/- 0.2) x 10(-12) cm3 molecule-1 s-1 was found. k......) to identify and quantify the reaction products. Absorption cross sections were quantified over the wavelength range 220-320 nm. At 240 nm, sigma(HOC(CH3)2CH2) = (2.4 +/- 0.3) x 10(-18) and sigma(HOC(CH3)2CH2O2) = (3.4 +/- 0.5) X 10(-18) cm2 molecule-1 have been obtained. Observed rate constants for......(HOC(CH3)2CH2O2. + NO) and k(HOC(CH3)2CH2O2. + NO2) were determined to be (4.9 +/- 0.9) X 10(-12) and (6.7 +/- 0.9) x 10(-12) cm3 molecule-1 s-1, respectively. In the FTIR experiments products were studied using chlorine-initiated oxidation in TBA/N2/Cl2 and TBA/N2/O2/Cl2 mixtures....

  16. Does chemically dispersing crude oil increase the exposure of fish to polynuclear aromatic hydrocarbons (PAH)?

    Energy Technology Data Exchange (ETDEWEB)

    Ramachandran, S.D.; Khan, C.W.; Hodson, P.V. [Queen' s Univ., Kingston, ON (Canada). Dept. of Biology; Lee, K. [Department of Fisheries and Oceans, Dartmouth, NS (Canada). Bedford Inst. of Oceanography

    2002-07-01

    Dispersants or surfactants are often used to clean up oil spills on water to minimize the impact of oil pollution. Their use as an oil spill countermeasure, however, is controversial because the risk of ecological effects depends on whether the dispersant increases or decreases the exposure of aquatic species to the toxic components of oil. This study involved the measurement of CYP1A induction and bile metabolites of polycyclic aromatic hydrocarbons (PAH) in trout exposed to Corexit 9500 dispersant, water accommodated fractions, and chemically enhanced water accommodated fractions of 3 crude oils. The objective was to see if fish are exposed to more PAH in dispersed oil compared to equivalent amounts of water accommodated fraction. Preliminary results indicated 10 times higher induction in fish exposed to chemically enhanced water accommodated fraction compared to water accommodated fractions. The dispersed oil in water had higher concentrations of alkylated PAH compared to the water accommodated fraction. As hydrocarbon concentrations increased, the trend for medaka embryos was first to hatch earlier, then have mild edema, followed by severe edema and finally mortality.

  17. Defects in cardiac function precede morphological abnormalities in fish embryos exposed to polycyclic aromatic hydrocarbons

    International Nuclear Information System (INIS)

    Fish embryos exposed to complex mixtures of polycyclic aromatic hydrocarbons (PAHs) from petrogenic sources show a characteristic suite of abnormalities, including cardiac dysfunction, edema, spinal curvature, and reduction in the size of the jaw and other craniofacial structures. To elucidate the toxic mechanisms underlying these different defects, we exposed zebrafish (Danio rerio) embryos to seven non-alkylated PAHs, including five two- to four-ring compounds that are abundant in crude oil and two compounds less abundant in oil but informative for structure-activity relationships. We also analyzed two PAH mixtures that approximate the composition of crude oil at different stages of weathering. Exposure to the three-ring PAHs dibenzothiophene and phenanthrene alone was sufficient to induce the characteristic suite of defects, as was genetic ablation of cardiac function using a cardiac troponin T antisense morpholino oligonucleotide. The primary etiology of defects induced by dibenzothiophene or phenanthrene appears to be direct effects on cardiac conduction, which have secondary consequences for late stages of cardiac morphogenesis, kidney development, neural tube structure, and formation of the craniofacial skeleton. The relative toxicity of the different mixtures was directly proportional to the amount of phenanthrene, or the dibenzothiophene-phenanthrene total in the mixture. Pyrene, a four-ring PAH, induced a different syndrome of anemia, peripheral vascular defects, and neuronal cell death, similar to the effects previously described for potent aryl hydrocarbon receptor ligands. Therefore, different PAH compounds have distinct and specific effects on fish at early life history stages

  18. Distribution and sources of polycyclic aromatic hydrocarbons in sediments from Kyeonggi Bay, Korea

    International Nuclear Information System (INIS)

    Sixty-six sediment samples were collected from Kyeonggi Bay, Korea, in December 1995 and analysed for a suite of 2-6 ring polycyclic aromatic hydrocarbons (PAHs). Sediments were collected in the Han River estuary, Incheon Harbour, from nearshore locations adjacent to large industrial complexes south of Incheon, and along transects toward the open sea. Concentrations of PAHs (9.1-1400 ng g-1 dry wt. with an average of 120 ng g-1) were positively correlated with organic carbon (OC) content and negatively correlated with mean sediment grain size. The highest PAH concentrations were in samples from inner Incheon Harbour basins; these levels decreased within a short distance from these heavily industrialised waterways. The sources of PAHs were determined to be primarily combustion nature based on the distribution of alkylated homologs to parent compounds. Overall, sediment PAHs in Kyeonggi Bay were lower than those in the United States and Europe. The potential for biological effects due to PAHs alone is expected to be low based on comparisons of individual and ΣPAH concentrations with effects-based and equilibrium partitioning-based sediment quality guidelines/criteria. (author)

  19. Photostability of CdSe quantum dots functionalized with aromatic dithiocarbamate ligands.

    Science.gov (United States)

    Tan, Yizheng; Jin, Song; Hamers, Robert J

    2013-12-26

    Organic ligands are widely used to enhance the ability of CdSe quantum dots (QDs) to resist photodegradation processes such as photo-oxidation. Because long alkyl chains may adversely affect the performance of QD devices that require fast and efficient charge transfer, shorter aromatic ligands are of increasing interest. In this work, we characterize the formation of phenyl dithiocarbamate (DTC) adducts on CdSe surfaces and the relative effectiveness of different para-substituted phenyl dithiocarbamates to enhance the aqueous photostability of CdSe QDs on TiO2. Optical absorption and photoluminescence measurements show that phenyl DTC ligands can be highly effective at reducing QD photocorrosion in water, and that ligands bearing electron-donating substituents are the most effective. A comparison of the QD photostability resulting from use of ligands bearing DTC versus thiol surface-binding groups shows that the DTC group provides greater QD photostability. Density functional calculations with natural bond order analysis show that the effectiveness of substituted phenyl DTC results from the ability of these ligands to remove positive charge away from the CdSe and to delocalize positive charge on the ligand. PMID:24256318

  20. Analysis of aromatic hydrocarbons in overburden from coal mines: Assessment of the environmental impact

    International Nuclear Information System (INIS)

    Bituminous coals are known to contain significant amounts of petroleum-like hydrocarbons trapped in the pore system of the macromolecular network. With increasing thermal stress acting upon coals under the particular conditions in their deposits, the relative amount of volatile aromatic hydrocarbons within the trapped bitumen increases until the coal reaches the rank of medium-volatile bituminous coals. Coking coals particularly are rich in compounds such as benzene, biphenyl, naphthalene, and their alkylated derivatives. Potential hazardous environmental impact of these hydrocarbons has to be considered when mining or reclaiming overburden because approximately 10% overburden material related to coal mining is coal. Exposure to long-term weathering destroys the pore system of coals, which might result in a release of highly volatile bituminous coal constituents into the atmosphere. This view is supported by analyses of coals present in overburden material. In the present study, the on-line combination of thermodesorption coupled to gas chromatography and mass spectrometry is shown to be an appropriate tool for the detection and quantitation of hydrocarbons of a wide boiling temperature range present in solid sample material. The method is preferentially suitable for the analysis of highly volatile constituents such as benzene, toluene, and xylenes, which are not quantitatively analyzed using conventional solvent-extraction methods

  1. Aromatic chemicals by iron-catalyzed hydrotreatment of lignin pyrolysis vapor.

    Science.gov (United States)

    Olcese, Roberto Nicolas; Lardier, George; Bettahar, Mohammed; Ghanbaja, Jaafar; Fontana, Sébastien; Carré, Vincent; Aubriet, Frédéric; Petitjean, Dominique; Dufour, Anthony

    2013-08-01

    Lignin is a potential renewable material for the production of bio-sourced aromatic chemicals. We present the first hydrotreatment of lignin pyrolysis vapors, before any condensation, using inexpensive and sustainable iron-silica (Fe/SiO2 ) and iron-activated carbon (Fe/AC) catalysts. Lignin pyrolysis was conducted in a tubular reactor and vapors were injected in a fixed bed of catalysts (673 K, 1 bar) with stacks to investigate the profile of coke deposit. More than 170 GC-analyzable compounds were identified by GCxGC (heart cutting)/flame ionization detector mass spectrometry. Lignin oligomers were analyzed by very high resolution mass spectrometry, called the "petroleomic" method. They are trapped by the catalytic fixed bed and, in particular, by the AC. The catalysts showed a good selectivity for the hydrodeoxygenation of real lignin vapors to benzene, toluene, xylenes, phenol, cresols, and alkyl phenols. The spent catalysts were characterized by temperature-programmed oxidation, transmission electron microscopy (TEM), and N2 sorption. Micropores in the Fe/AC catalyst are completely plugged by coke deposits, whereas the mesoporous structure of Fe/SiO2 is unaffected. TEM images reveal two different types of coke deposit: 1) catalytic coke deposited in the vicinity of iron particles and 2) thermal coke (carbonaceous particles ≈1 μm in diameter) formed from the gas-phase growth of lignin oligomers. PMID:23784799

  2. Does chemically dispersing crude oil increase the exposure of fish to polynuclear aromatic hydrocarbons (PAH)?

    International Nuclear Information System (INIS)

    Dispersants or surfactants are often used to clean up oil spills on water to minimize the impact of oil pollution. Their use as an oil spill countermeasure, however, is controversial because the risk of ecological effects depends on whether the dispersant increases or decreases the exposure of aquatic species to the toxic components of oil. This study involved the measurement of CYP1A induction and bile metabolites of polycyclic aromatic hydrocarbons (PAH) in trout exposed to Corexit 9500 dispersant, water accommodated fractions, and chemically enhanced water accommodated fractions of 3 crude oils. The objective was to see if fish are exposed to more PAH in dispersed oil compared to equivalent amounts of water accommodated fraction. Preliminary results indicated 10 times higher induction in fish exposed to chemically enhanced water accommodated fraction compared to water accommodated fractions. The dispersed oil in water had higher concentrations of alkylated PAH compared to the water accommodated fraction. As hydrocarbon concentrations increased, the trend for medaka embryos was first to hatch earlier, then have mild edema, followed by severe edema and finally mortality

  3. Distribution and sources of polycyclic aromatic hydrocarbon (PAH) in marine environment of China

    Energy Technology Data Exchange (ETDEWEB)

    Zheng Jinshu; Bruce J. Richardson; O. Shouming; Zheng Jianhua [Third Institute of Oceanography, Xiamen (China). State Oceanic Administration

    2004-07-01

    Polycyclic aromatic hydrocarbons (PAHs) are potentially carcinogenic and mutagenic compounds that have raised considerable environmental concern. The highest concentrations of PAHs in the coastal sediment samples in China was 5.8-11.0 {mu}g/g (dry weight) in the core from the Huangpu River, Shanghai. The second highest concentration of PAHs was 4.42 {mu}g/g (dry weight) in surface sediment of Victoria Harbour in Hong Kong, and 5.73 {mu}g/g (dry weight) in sediment of Jiaozhou Bay, Qingdao City. The low concentrations of PAHs were always in the sediments far away from industrial zones and cities, and ranged from 0.10 to 0.30 {mu}g/g (dry weight). Several environmental parameters are considered for the identification of sources of PAHs in marine environment. High proportion of naphthalene, low molecular weight PAHs and alkylated PAHs, plus high ratio of phenanthrene to anthracene ({gt}15) and low ratio of fluoranthene to pyrene ({lt}1) suggested a petrogenic source. According to these parameters, the Changjiang (Yangtze) River estuary of Shanghai, Jiaozhou Bay of Qingdao City, Zhujiang (Pearl) River mouth, Jiulong River mouth and most of Hong Kong coastal waters were heavily contaminated by PAHs from petrogenic sources. However, PAHs in rural coastal areas were dominated by pyrolytic origin PAHs. This review clearly showed that oil pollution and incomplete combustion of oil, coal and biomass are the main reason for PAHs anormalies in the study areas.

  4. Distribution and Sources of Polycyclic Aromatic Hydrocarbon (PAH) in Marine Environment of China

    Institute of Scientific and Technical Information of China (English)

    ZHENG Jinshu(郑金树); Bruce J. Richardson; O.Shouming; ZHENG Jianhua(郑建华)

    2004-01-01

    Polycyclic aromatic hydrocarbons (PAHs) are potentially carcinogenic and mutagenic compounds that have raised considerable environmental concern. The highest concentrations of PAHs in the coastal sediment samples in China was 5.8-11.0μg/g (dry weight) in the core from the Huangpu River, Shanghai. The second highest concentration of PAHs was 4.42μg/g (dry weight) in surface sediment of Victoria Harbour in Hong Kong, and 5.73μg/g (dry weight) in sediment of Jiaozhou Bay, Qingdao City. The low concentrations of PAHs were always in the sediments far away from industrial zones and cities, and ranged from 0.10 to 0.30μg/g (dry weight). Several environmental parameters are considered for the identification of sources of PAHs in marine environment. High proportion of naphthalene, low molecular weight PAHs and alkylated PAHs, plus high ratio of phenanthrene to anthracene (>15) and low ratio of fluoranthene to pyrene (<1) suggested a petrogenic source. According to these parameters, the Changjiang (Yangtze) River estuary of Shanghai, Jiaozhou Bay of Qingdao City, Zhujiang (Pearl) River mouth, Jiulong River mouth and most of Hong Kong coastal waters were heavily contaminated by PAHs from petrogenic sources. However, PAHs in rural coastal areas were dominated by pyrolytic origin PAHs. This review clearly showed that oil pollution and incomplete combustion of oil, coal and biomass are the main reason for PAHs anormalies in the study areas.

  5. Divergent Reactivity of Alkyl Aryl Sulfones with Bases: Selective Functionalization of ortho-Aryl and alpha-Alkyl Units Enabled by a Unique Carbanion Transmetalation

    Czech Academy of Sciences Publication Activity Database

    Řehová, Lucie; Císařová, I.; Jahn, Ullrich

    2014-01-01

    Roč. 2014, č. 7 (2014), s. 1461-1476. ISSN 1434-193X R&D Projects: GA ČR GAP207/11/1598 Institutional support: RVO:61388963 Keywords : sulfones * transmetalation * lithiation * deprotonation * alkylation * acidity Subject RIV: CC - Organic Chemistry Impact factor: 3.065, year: 2014

  6. Far infrared (terahertz) spectroscopy of a series of polycyclic aromatic hydrocarbons and application to structure interpretation of asphaltenes and related compounds

    Science.gov (United States)

    Cataldo, Franco; Angelini, Giancarlo; García-Hernández, D. A.; Manchado, Arturo

    2013-07-01

    A series of 33 different polycyclic aromatic hydrocarbons (PAHs) were studied by far infrared spectroscopy (terahertz spectroscopy) in the spectral range comprised between 600 and 50 cm-1. In addition to common PAHs like naphthalene, anthracene, phenanthrene, fluoranthene, picene, pyrene, benzo[α]pyrene, and perylene, also quite unusual PAHs were studied like tetracene, pentacene, acenaphtene, acenaphtylene, triphenylene, and decacyclene. A series of alkylated naphthalenes and anthracenes were studied as well as methypyrene. Partially or totally hydrogenated PAHs were also object of the present investigation, ranging from tetrahydronaphthalene (tetralin) to decahydronaphthalene (decalin), 9,10-dihydroanthracene, 9,10-dihydrophenanthrene, hexahydropyrene, and dodecahydrotriphenylene. Finally, the large and quite rare PAHs coronene, quaterrylene, hexabenzocoronene, and dicoronylene were studied by far infrared spectroscopy. The resulting reference spectra were used in the interpretation of the chemical structure of asphaltenes (as extracted from a heavy petroleum fraction and from bitumen), the chemical structures of other petroleum fractions known as DAE (distillate aromatic extract) and RAE (residual aromatic extract), and a possible interpretation of components of the chemical structure of anthracite coal. Asphaltenes, heavy petroleum fractions, and coal were proposed as model compounds for the interpretation of the emission spectra of certain proto-planetary nebulae (PPNe) with a good matching in the mid infrared between the band pattern of the PPNe emission spectra and the spectra of these oil fractions or coal. Although this study was finalized in an astrochemical context, it may find application also in the petroleum and coal chemistry.

  7. Thiolated alkyl-modified carbomers: Novel excipients for mucoadhesive emulsions.

    Science.gov (United States)

    Bonengel, Sonja; Hauptstein, Sabine; Leonaviciute, Gintare; Griessinger, Julia; Bernkop-Schnürch, Andreas

    2015-07-30

    The aim of this study was the design and evaluation of mucoadhesive emulsifying polymeric excipients. Three thiol bearing ligands with increasing pKa values of their sulfhydryl group, namely 4-aminothiophenol (pKa=6.86), l-cysteine (pKa=8.4) and d/l-homocysteine (pKa=10.0) were coupled to the polymeric backbone of alkyl-modified carbomer (PA1030). Resulting conjugates displayed 818.5μmol 4-aminothiophenol, 698.5μmol cysteine and 651.5μmol homocysteine per gram polymer and were evaluated regarding the reactivity of thiol groups, emulsifying and mucoadhesive properties. In general, the synthesized conjugates showed a pH dependent reactivity, whereby the fastest oxidation occurred in PA1030-cysteine, as almost no free thiol groups could be detected after 120min. Emulsification of medium chain triglycerides was feasible with all synthesized conjugates leading to oil-in-water-emulsions. Emulsions with PA1030-cysteine displayed the highest stability and the smallest droplet size among the tested formulations. Oxidation and consequently cross-linking of the thiomers prior to the emulsification process led to an overall decreased emulsion stability. Evaluating mucosal residence time of thiomer emulsions on porcine buccal mucosa, a 9.2-fold higher amount of formulation based on PA1030-cysteine remained on the mucosal tissue within 3h compared to the unmodified polymer. According to these results, the highest reactive ligand l-cysteine seems to be most promising in order to obtain thiolated polymers for the preparation of mucoadhesive o/w-emulsions. PMID:25857707

  8. Alkyl nitrate production and persistence in the Mexico City Plume

    Directory of Open Access Journals (Sweden)

    G. Sachse

    2009-11-01

    Full Text Available Alkyl and multifunctional nitrates (ΣANs have been observed to be a significant fraction of NOy in a number of different chemical regimes. Their formation is an important free radical chain termination step ending production of ozone and possibly affecting formation of secondary organic aerosol. ΣANs also represent a potentially large, unmeasured contribution to OH reactivity and are a major pathway for the removal of nitrogen oxides from the atmosphere. Numerous studies have investigated the role of nitrate formation from biogenic compounds. Less attention has been paid to the role ΣANs may play in the complex mixtures of hydrocarbons typical of urban settings. Measurements of ΣANs, NO2, total peroxy nitrates (ΣPNs, HNO3 and a wide suite of hydrocarbons were obtained from the NASA DC-8 aircraft during spring of 2006 in and around Mexico City and the Gulf of Mexico. ΣANs were observed to be 10–20% of NOy in the Mexico City plume and to increase in importance with increased photochemical age. We describe three conclusions: 1 Correlations of ΣANs with odd-oxygen (Ox indicate a stronger role for ΣANs in the photochemistry of Mexico City than is expected based on currently accepted photochemical mechanisms, 2 ΣAN formation suppresses peak ozone production rates by as much as 30% in the near-field of Mexico City and 3 ΣANs play a comparable role to ΣPNs in the export of NOy to the Gulf Region.

  9. Radiation Effects on PP/PS Blends as a Model of Protection Effects by Aromatics

    International Nuclear Information System (INIS)

    molecular weight compounds, starting with hydrogen. Hydrogen is abstracted from PP, causing a variety of effects, e.g. forming alkyl radicals on the chain. The PS competes successfully with oxygen for these centers, preventing the oxidation of polymers. The aromatic free PP is oxidized easily, whereas the presence of PS prevents this reaction. The paper showed already the advantages of determination of radiation yield of hydrogen in the evaluation of mechanisms of radiolysis of hydrogenated nitrile rubber. Also methane and carbon oxide can be measured by gas chromatography now, as well the consumption of oxygen which reacts with free radicals on the polypropylene chain. The range of protective effect of PS in the zone of single-ionization spurs is estimated to 8-12 mers of PP

  10. Aromatic plant production on metal contaminated soils

    Energy Technology Data Exchange (ETDEWEB)

    Zheljazkov, Valtcho D. [Mississippi State, Department of Plant and Soil Sciences and North Mississippi Research and Extension Center, 5421 Highway 145 South, Verona, MS 38879 (United States)], E-mail: vj40@pss.msstate.edu; Craker, Lyle E.; Xing Baoshan [Department of Plant and Soil Sciences, 12 Stockbridge Hall, University of Massachusetts, Amherst, MA 01003 (United States); Nielsen, Niels E. [Plant Nutrition and Soil Fertility Lab, Department of Agricultural Sciences, Royal Veterinary and Agricultural University, Thorvaldsensvej 40, DK1871, Copenhagen (Denmark); Wilcox, Andrew [Harper Adams University College, Newport, Shropshire, TF10 8NB (United Kingdom)

    2008-06-01

    Field and container experiments were conducted to assess the feasibility of growing aromatic crops in metal contaminated areas and the effect of metals on herbage and oil productivity. The field experiments were conducted in the vicinities of the Non-Ferrous Metals Combine (Zn-Cu smelter) near Plovdiv, Bulgaria using coriander, sage, dill, basil, hyssop, lemon balm, and chamomile grown at various distances from the smelter. Herbage essential oil yields of basil, chamomile, dill, and sage were reduced when they were grown closer to the smelter. Metal removal from the site with the harvestable plant parts was as high as 180 g ha{sup -1} for Cd, 660 g ha{sup -1} for Pb, 180 g ha{sup -1} for Cu, 350 g ha{sup -1} for Mn, and 205 g ha{sup -1} for Zn. Sequential extraction of soil demonstrated that metal fractionation was affected by the distance to the smelter. With decreasing distance to the smelter, the transfer factor (TF) for Cu and Zn decreased but increased for Cd, while the bioavailability factor (BF) for Cd, Pb, Cu, Mn, and Zn decreased. Scanning electron microscopy and X-ray microanalyses of contaminated soil verified that most of the Pb, Cd, Mn, Cu, and Zn were in the form of small (< 1 {mu}m) particles, although there were larger particles (1-5 {mu}m) with high concentrations of individual metals. This study demonstrated that high concentrations of heavy metals in soil or growth medium did not result in metal transfer into the essential oil. Of the tested metals, only Cu at high concentrations may reduce oil content. Our results demonstrated that aromatic crops may not have significant phytoremediation potential, but growth of these crops in metal contaminated agricultural soils is a feasible alternative. Aromatic crops can provide economic return and metal-free final product, the essential oil.

  11. Aromatic plant production on metal contaminated soils

    International Nuclear Information System (INIS)

    Field and container experiments were conducted to assess the feasibility of growing aromatic crops in metal contaminated areas and the effect of metals on herbage and oil productivity. The field experiments were conducted in the vicinities of the Non-Ferrous Metals Combine (Zn-Cu smelter) near Plovdiv, Bulgaria using coriander, sage, dill, basil, hyssop, lemon balm, and chamomile grown at various distances from the smelter. Herbage essential oil yields of basil, chamomile, dill, and sage were reduced when they were grown closer to the smelter. Metal removal from the site with the harvestable plant parts was as high as 180 g ha-1 for Cd, 660 g ha-1 for Pb, 180 g ha-1 for Cu, 350 g ha-1 for Mn, and 205 g ha-1 for Zn. Sequential extraction of soil demonstrated that metal fractionation was affected by the distance to the smelter. With decreasing distance to the smelter, the transfer factor (TF) for Cu and Zn decreased but increased for Cd, while the bioavailability factor (BF) for Cd, Pb, Cu, Mn, and Zn decreased. Scanning electron microscopy and X-ray microanalyses of contaminated soil verified that most of the Pb, Cd, Mn, Cu, and Zn were in the form of small (< 1 μm) particles, although there were larger particles (1-5 μm) with high concentrations of individual metals. This study demonstrated that high concentrations of heavy metals in soil or growth medium did not result in metal transfer into the essential oil. Of the tested metals, only Cu at high concentrations may reduce oil content. Our results demonstrated that aromatic crops may not have significant phytoremediation potential, but growth of these crops in metal contaminated agricultural soils is a feasible alternative. Aromatic crops can provide economic return and metal-free final product, the essential oil

  12. Biosynthesis of the Aromatic Amino Acids.

    Science.gov (United States)

    Pittard, James; Yang, Ji

    2008-09-01

    This chapter describes in detail the genes and proteins of Escherichia coli involved in the biosynthesis and transport of the three aromatic amino acids tyrosine, phenylalanine, and tryptophan. It provides a historical perspective on the elaboration of the various reactions of the common pathway converting erythrose-4-phosphate and phosphoenolpyruvate to chorismate and those of the three terminal pathways converting chorismate to phenylalanine, tyrosine, and tryptophan. The regulation of key reactions by feedback inhibition, attenuation, repression, and activation are also discussed. Two regulatory proteins, TrpR (108 amino acids) and TyrR (513 amino acids), play a major role in transcriptional regulation. The TrpR protein functions only as a dimer which, in the presence of tryptophan, represses the expression of trp operon plus four other genes (the TrpR regulon). The TyrR protein, which can function both as a dimer and as a hexamer, regulates the expression of nine genes constituting the TyrR regulon. TyrR can bind each of the three aromatic amino acids and ATP and under their influence can act as a repressor or activator of gene expression. The various domains of this protein involved in binding the aromatic amino acids and ATP, recognizing DNA binding sites, interacting with the alpha subunit of RNA polymerase, and changing from a monomer to a dimer or a hexamer are all described. There is also an analysis of the various strategies which allow TyrR in conjunction with particular amino acids to differentially affect the expression of individual genes of the TyrR regulon. PMID:26443741

  13. Isobutane/2-butene alkylation over potential heterogeneous catalysts in a slurry reactor

    Energy Technology Data Exchange (ETDEWEB)

    Roervik, T.

    1996-12-31

    The trend towards more effective use of fossil fuels and reduced environmental pollution represents a major task of improvement within the refinery processes. The highly isomerized and high octane paraffins produced from isobutane and light olefins by alkylation fulfill all the requirements for reformulated gasoline. This doctoral thesis discusses new catalyst systems because of their potential in alkylation. A slurry reactor apparatus for solid-acid catalysed isobutane/butene alkylation was developed and used to investigate the performance of various heterogeneous catalysts. The selected materials were mainly zeolite types with faujasite structures. The samples were characterized by various methods before alkylation. In general, the order of decreasing catalyst activity after 3 h of reaction at 80{sup o}C was found to be: H-EMT >> H-FAU, dealuminated H-FAU >> NS.500, TA-Y, CeY-98 > Nafion-H. The order of decreasing alkylate selectivity of the catalysts was: H-EMT >> dealuminated H-FAU > H-FAU >> Nafion-H > CeY-98 > TA-Y > H-SAPO-37, NS.500. H-EMT was the most promising system for further development, also because of the very low formation of the undesirable isooctenes and a high selectivity towards isooctanes among the alkylates. A high density of accessible strong acid sites was found to be essential for a high alkylation activity and selectivity. Open structure, like hexagonal faujasite, was advantageous. The distribution of trimethylpentanes formed in zeolites was ascribed to pore restrictions as a major factor. The effect of operating conditions on catalyst performance was investigated statistically, and a high dilution of butene in the slurry reactor was found to be very important. 153 refs., 40 figs., 12 tabs.

  14. Biodegradation Rates of Aromatic Contaminants in Biofilm Reactors

    DEFF Research Database (Denmark)

    Arcangeli, Jean-Pierre; Arvin, Erik

    1995-01-01

    This study has shown that microorganisms can adapt to degrade mixtures of aromatic pollutants at relatively high rates in the μg/l concentration range. The biodegradation rates of the following compounds were investigated in biofilm systems: aromatic hydrocarbons, phenol, methylphenols......, chlorophenols, nitrophenol, chlorobenzenes and aromatic nitrogen-, sulphur- or oxygen-containing heterocyclic compounds (NSO-compounds). Furthermore, a comparison with degradation rates observed for easily degradable organics is also presented. At concentrations below 20-100 μg/l the degradation of the aromatic...

  15. Critical analysis of the local aromaticity concept in polyaromatic hydrocarbons.

    Science.gov (United States)

    Bultinck, Patrick

    2007-01-01

    A large number of local aromaticity indices for the benzenoid rings in polyaromatic hydrocarbons is computed. The results are interpreted, supporting Clar's hypothesis, and mutual correlations are investigated. It is shown that there are good correlations between all indices that strictly allow comparing benzenoid character. Poor correlations are found with NICS. A rationale is offered, yielding the conclusion that NICS and ring current maps follow a fundamentally different path to local aromaticity. In this sense the lack of correlation is not due to a real multidimensional character of aromaticity but rather to confusion and vagueness of the aromaticity concept. PMID:17328438

  16. Aromatic compounds from three Brazilian Lauraceae species

    Directory of Open Access Journals (Sweden)

    Andrea Nastri de Luca Batista

    2010-01-01

    Full Text Available Phytochemical investigations on three Brazilian Lauraceae species from the Cerrado region of São Paulo State, Ocotea corymbosa (Meins Mez., O. elegans Mez. and Persea pyrifolia Nees & Mart. ex Nees resulted in the isolation of flavonoids, an ester of the 4-O-E-caffeoylquinic acid, an aromatic sesquiterpene besides furofuran lignans. This is the first chemical study on the leaves of Ocotea elegans and O. corymbosa as well as the first report of non-volatile compounds from Persea pyrifolia.

  17. Carcinogenic potential of hydrotreated petroleum aromatic extracts.

    Science.gov (United States)

    Doak, S M; Hend, R W; van der Wiel, A; Hunt, P F

    1985-06-01

    Five experimental petroleum extracts were produced from luboil distillates derived from Middle East paraffinic crude by solvent extraction and severe hydrotreatment. The polycyclic aromatic content (PCA) of the extracts was determined by dimethyl sulphoxide extraction and ranged from 3.7-9.2% w/w. The five extracts were evaluated for their potential to induce cutaneous and systemic neoplasia in female mice derived from Carworth Farm No 1 strain (CF1). The test substances were applied undiluted (0.2 ml per application) to the shorn dorsal skin twice weekly for up to 78 weeks, with 48 mice in each treatment group and 96 in the untreated control group; two further groups, each of 48 mice, were similarly treated either with a non-hydrotreated commercial aromatic extract (PCA content, 19.7% w/v) or with a low dose of benzo(a)pyrene (12.5 micrograms/ml acetone). The mice were housed individually in polypropylene cages in specified pathogen free conditions. The incidence of cutaneous and systemic tumours was determined from histological analysis of haematoxylin and eosin stained tissue sections. The results were correlated with the PCA content of the extracts and compared with those from female mice exposed to a non-hydrotreated commercial aromatic extract. Four of the hydrotreated extracts were carcinogenic for murine skin; the two products with the lower PCA contents were less carcinogenic than the products with the higher PCA contents and all were less carcinogenic than the commercial extract. One extract with the lowest PCA content was non-carcinogenic. Thus refining by severe hydrotreatment was an effective method of reducing the carcinogenic potential of petroleum aromatic extracts. Although other physicochemical properties may influence the biological activity of oil products, the PCA content determined by dimethyl sulphoxide extraction may be a useful indicator of the potential of oil products to induce cutaneous tumours in experimental animals. There was no

  18. Aromatics oxidation and soot formation in flames

    Energy Technology Data Exchange (ETDEWEB)

    Howard, J.B.; Pope, C.J.; Shandross, R.A.; Yadav, T. [Massachusetts Institute of Technology, Cambridge (United States)

    1993-12-01

    This project is concerned with the kinetics and mechanisms of aromatics oxidation and soot and fullerenes formation in flames. The scope includes detailed measurements of profiles of stable and radical species concentrations in low-pressure one-dimensional premixed flames. Intermediate species identifications and mole fractions, fluxes, and net reaction rates calculated from the measured profiles are used to test postulated reaction mechanisms. Particular objectives are to identify and to determine or confirm rate constants for the main benzene oxidation reactions in flames, and to characterize fullerenes and their formation mechanisms and kinetics.

  19. Photoinduced dynamics in protonated aromatic amino acid

    CERN Document Server

    Grégoire, Gilles; Barat, Michel; Fayeton, Jacqueline; Dedonder-Lardeux, Claude; Jouvet, Christophe

    2008-01-01

    UV photoinduced fragmentation of protonated aromatics amino acids have emerged the last few years, coming from a situation where nothing was known to what we think a good understanding of the optical properties. We will mainly focus this review on the tryptophan case. Three groups have mostly done spectroscopic studies and one has mainly been involved in dynamics studies of the excited states in the femtosecond/picosecond range and also in the fragmentation kinetics from nanosecond to millisecond. All these data, along with high level ab initio calculations, have shed light on the role of the different electronic states of the protonated molecules upon the fragmentation mechanisms.

  20. Mild and Phosphine-Free Iron-Catalyzed Cross-Coupling of Nonactivated Secondary Alkyl Halides with Alkynyl Grignard Reagents

    OpenAIRE

    Cheung, Chi Wai; Ren, Peng; Hu, Xile

    2014-01-01

    A simple protocol for iron-catalyzed cross-coupling of nonactivated secondary alkyl bromides and iodides with alkynyl Grignard reagents at room temperature has been developed. A wide range of secondary alkyl halides and terminal alkynes are tolerated to afford the substituted alkynes in good yields. A slight modification of the reaction protocol also allows for cross-coupling with a variety of primary alkyl halides.

  1. The effect of ultrasound on the catalytic activity of alkaline carbons: preparation of N-alkyl imidazoles

    Energy Technology Data Exchange (ETDEWEB)

    Duran-Valle, C.J.; Ferrera-Escudero, S.; Calvino-Casilda, V.; Diaz-Teran, J.; Martin-Aranda, R.M

    2004-11-15

    N-Alkyl imidazoles have been prepared by sonochemical irradiation of imidazole and 1-bromobutane using alkaline promoted carbons. Under the experimental conditions, N-alkyl imidazoles can be prepared with a high activity and selectivity. It is observed that imidazole conversion increases in parallel with increasing basicity of the catalyst. For comparison, the alkylation of imidazole has also been performed in a batch reactor system under thermal activation.

  2. Anaerobic degradation of alkylated benzenes in denitrifying laboratory aquifer columns

    International Nuclear Information System (INIS)

    Toluene and m-xylene were rapidly mineralized in an anaerobic laboratory aquifer column operated under continuous-flow conditions with nitrate as an electron acceptor. The oxidation of toluene and m-xylene was coupled with the reduction of nitrate, and mineralization was confirmed by trapping 14CO2 evolved from 14C-ring-labeled substrates. Substrate degradation also took place when nitrous oxide replaced nitrate as an electron acceptor, but decomposition was inhibited in the presence of molecular oxygen or after the substitution of nitrate by nitrite. The m-xylene-adapted microorganisms in the aquifer column degraded toluene, benzaldehyde, benzoate, m-toluylaldehyde, m-toluate, m-cresol, p-cresol, and p-hydroxybenzoate but were unable to metabolize benzene, naphthalene, methylcyclohexane, and 1,3-dimethylcyclohexane. Isotope-dilution experiments suggested benzoate as an intermediate formed during anaerobic toluene metabolism. The finding that the highly water-soluble nitrous oxide served as electron acceptor for the anaerobic mineralization of some aromatic hydrocarbons may offer attractive options for the in situ restoration of polluted aquifers

  3. An Aromatic Inventory of the Local Volume

    CERN Document Server

    Marble, A R; 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

    2010-01-01

    Using infrared photometry from the Spitzer Space Telescope, we perform the first inventory of aromatic feature emission (AFE, but also commonly referred to as PAH 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 IRAC 8 micron 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 IRS spectra and equivalent photometry. A potential factor of two improvement could be realized with suitable 5.5 and 10 micron photometry, such as what may be provided in the future by JWST. 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 lum...

  4. Molecular dynamics studies of aromatic hydrocarbon liquids

    International Nuclear Information System (INIS)

    This project mainly involves a molecular dynamics and Monte Carlo study of the effect of molecular shape on thermophysical properties of bulk fluids with an emphasis on the aromatic hydrocarbon liquids. In this regard we have studied the modeling, simulation methodologies, and predictive and correlating methods for thermodynamic properties of fluids of nonspherical molecules. In connection with modeling we have studied the use of anisotropic site-site potentials, through a modification of the Gay-Berne Gaussian overlap potential, to successfully model the aromatic rings after adding the necessary electrostatic moments. We have also shown these interaction sites should be located at the geometric centers of the chemical groups. In connection with predictive methods, we have shown two perturbation type theories to work well for fluids modeled using one-center anisotropic potentials and the possibility exists for extending these to anisotropic site-site models. In connection with correlation methods, we have studied, through simulations, the effect of molecular shape on the attraction term in the generalized van der Waals equation of state for fluids of nonspherical molecules and proposed a possible form which is to be studied further. We have successfully studied the vector and parallel processing aspects of molecular simulations for fluids of nonspherical molecules

  5. Alkyl caffeates improve the antioxidant activity, antitumor property and oxidation stability of edible oil.

    Directory of Open Access Journals (Sweden)

    Jun Wang

    Full Text Available Caffeic acid (CA is distributed widely in nature and possesses strong antioxidant activity. However, CA has lower solubility in non-polar media, which limits its application in fat-soluble food. To increase the lipophilicity of natural antioxidant CA, a series of alkyl caffeates were synthesized and their antioxidant and antitumor activities were investigated. The antioxidant parameters, including the induction period, acid value and unsaturated fatty acid content, of the alkyl caffeates in edible oil were firstly investigated. The results indicated that alkyl caffeates had a lower DPPH IC₅₀ (14-23 µM compared to CA, dibutyl hydroxy toluene (BHT and Vitamin C (24-51 µM, and significantly inhibited four human cancer cells (SW620, SW480, SGC7901 and HepG2 with inhibition ratio of 71.4-78.0% by a MTT assay. With regard to the induction period and acid value assays, methyl and butyl caffeates had higher abilities than BHT to restrain the oxidation process and improve the stability of edible oil. The addition of ethyl caffeate to oil allowed maintenance of a higher unsaturated fatty acid methyl ester content (68.53% at high temperatures. Overall, the alkyl caffeats with short chain length (n<5 assessed better oxidative stability than those with long chain length. To date, this is the first report to the correlations among the antioxidant activity, anticancer activity and oxidative stability of alkyl caffeates.

  6. Kinetics of toluene alkylation with methanol catalyzed by pure and hybridized HZSM-5 catalysts

    KAUST Repository

    Alabi, Wahab

    2012-07-01

    A kinetic study of toluene alkylation with methanol was performed over pure HZSM-5, mordenite/ZSM-5 (hybrid of mordenite and HZSM-5), and ZM13 (composite mixture of HZSM-5 and MCM-41 at pH 13). Experimental runs were conducted using a batch fluidized bed reactor at temperatures of 300, 350 and 400 °C and reaction times of 3, 5, 7, 10, 13, 15 and 20. s. The rate of toluene methylation and toluene disproportionation were studied on the three catalysts (toluene alkylation is usually accompanied by toluene disproportionation on acid catalyst). Based on the results obtained, a simplified power law kinetic model consisting of three reactions was developed to estimate the activation energies of toluene methylation and disproportionation simultaneously. Coke formation on catalysts was accounted for using both reaction time and reactant conversion decay functions. All parameters were estimated based on quasi-steady state approximation. Estimated kinetic parameters were in good agreement with experimental results. The order of alkylation ability of the catalysts was found to be ZM13 > HZSM-5 > mordenite/ZSM-5, while the reverse is for toluene disproportionation (mordenite/ZSM-5 > HZSM-5 > ZM13). Thus, alkylation of toluene is most favorable on ZM13 due to combined effect of mesoporosity induced through its synthetic route and acid content. Toluene/MeOH molar ratio of 1:1 was most suitable for toluene alkylation reaction. © 2012 Elsevier B.V.

  7. ORGANIC-INORGANIC HYBRIDS PREPARED FROM ALKYL PHOSPHONIUM SALTS INTERCALATED MONTMORILLONITES

    Directory of Open Access Journals (Sweden)

    SAHELI GANGULY

    2012-12-01

    Full Text Available Present investigation is focused on systematic and detailed characterization of alkyl phosphonium intercalated montmorillonite (MMT. The objective of the work is to provide a better understanding of the specific changes in properties of the hybrid material with changes in structure of incoming organic cations. In the present work, Na-MMT was intercalated with phosphonium salts of two different cationic head compositions namely alkyl triphenyl and alkyl tributyl groups. Length of alkyl chain was also varied. Resultant organic-inorganic hybrids were characterized by X-ray diffraction (XRD, Transmission electron microscopy (TEM, Thermogravimetry (TG and Fourier transformed infrared spectroscopy (FTIR. Effective volume occupied by the cationic heads influenced interlayer arrangements. Intercalated MMT with two different cationic heads behaved differently in relation to thermal decomposition patterns. Possible explanation was given based on hybridization of bonds. Van der Waals attachment of alkyl chains influenced the interlayer stacking and organic loading. Attempts were made to correlate the changes in properties of intercalated MMT with the structural aspects of incoming organic cations.

  8. Structural properties of the active layer of discotic hexabenzocoronene/perylene diimide bulk hetero junction photovoltaic devices: The role of alkyl side chain length

    International Nuclear Information System (INIS)

    We investigate thin blend films of phenyl-substituted hexa-peri-hexabenzocoronenes (HBC) with various alkyl side chain lengths ((CH2)n, n = 6, 8, 12 and 16)/perylenediimide (PDI). These blends constitute the active layers in bulk-hetero junction organic solar cells we studied recently [1]. Their structural properties are studied by both scanning electron microscopy and X-ray diffraction measurements. The results support the evidence for the formation of HBC donor-PDI acceptor complexes in all blends regardless of the side chain length of the HBC molecule. These complexes are packed into a layered structure parallel to the substrate for short side chain HBC molecules (n = 6 and 8). The layered structure is disrupted by increasing the side chain length of the HBC molecule and eventually a disordered structure is formed for long side chains (n > 12). We attribute this behavior to the size difference between the aromatic parts of the HBC and PDI molecules. For short side chains, the size difference results in a room for the side chains of the two molecules to fill in the space around the aromatic cores. For long side chains (n > 12), the empty space will not be enough to accommodate this increase, leading to the disruption of the layered structure and a rather disordered structure is formed. Our results highlight the importance of the donor-acceptor interaction in a bulk heterojunction active layer as well as the geometry of the two molecules and their role in determining the structure of the active layer and thus their photovoltaic performance.

  9. Biodegradation Rates of Aromatic Contaminants in Biofilm Reactors

    DEFF Research Database (Denmark)

    Arcangeli, Jean-Pierre; Arvin, Erik

    1995-01-01

    , chlorophenols, nitrophenol, chlorobenzenes and aromatic nitrogen-, sulphur- or oxygen-containing heterocyclic compounds (NSO-compounds). Furthermore, a comparison with degradation rates observed for easily degradable organics is also presented. At concentrations below 20-100 μg/l the degradation of the aromatic...

  10. Products Distribution of Meta-Oriented Aromatic Polyamide Needs Improvement

    Institute of Scientific and Technical Information of China (English)

    Sun Maojian

    2007-01-01

    @@ Capacity holding the second place in the world Metaoriented aromatic polya-mide fiber was first developed by DuPont of the United States. Commercial production began in the late 1960s.Today the world's capacity to produce meta-oriented aromatic polyamide fiber is 28 150t/a, and DuPont holds a 78% market share.

  11. High atmosphere-ocean exchange of semivolatile aromatic hydrocarbons

    Science.gov (United States)

    González-Gaya, Belén; Fernández-Pinos, María-Carmen; Morales, Laura; Méjanelle, Laurence; Abad, Esteban; Piña, Benjamin; Duarte, Carlos M.; Jiménez, Begoña; Dachs, Jordi

    2016-06-01

    Polycyclic aromatic hydrocarbons, and other semivolatile aromatic-like compounds, are an important and ubiquitous fraction of organic matter in the environment. The occurrence of semivolatile aromatic hydrocarbons is due to anthropogenic sources such as incomplete combustion of fossil fuels or oil spills, and other biogenic sources. However, their global transport, fate and relevance for the carbon cycle have been poorly assessed, especially in terms of fluxes. Here we report a global assessment of the occurrence and atmosphere-ocean fluxes of 64 polycyclic aromatic hydrocarbons analysed in paired atmospheric and seawater samples from the tropical and subtropical Atlantic, Pacific and Indian oceans. The global atmospheric input of polycyclic aromatic hydrocarbons to the global ocean is estimated at 0.09 Tg per month, four times greater than the input from the Deepwater Horizon spill. Moreover, the environmental concentrations of total semivolatile aromatic-like compounds were 102-103 times higher than those of the targeted polycyclic aromatic hydrocarbons, with a relevant contribution of an aromatic unresolved complex mixture. These concentrations drive a large global deposition of carbon, estimated at 400 Tg C yr-1, around 15% of the oceanic CO2 uptake.

  12. Laboratory Investigation of Organic Aerosol Formation from Aromatic Hydrocarbons

    Science.gov (United States)

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

    2006-08-23

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

  13. Bis-perfluoroalkylation of aromatic compounds with sodium perfluoroalkanesulfinates

    Institute of Scientific and Technical Information of China (English)

    LIU, Jin-Tao(刘金涛); LU, He-Jun(吕贺军)

    2000-01-01

    Bis-perfluoroalkylation of aromatic compounds such as dimethoxybenzenes (2,4,6), anisole (8), pyridine (10) and quinoline (13) was accomplished by reaction with excess sodium perfluoroalkanesulfinates, RFSO2Na (1), in the presence of Mn(OAc)3·2H2O under mild conditions. The reaction provides a facile method for the synthesis of bis-perfluoroalkylated aromatic compounds.

  14. 40 CFR 721.757 - Polyoxyalkylene substituted aromatic azo colorant.

    Science.gov (United States)

    2010-07-01

    ... azo colorant. 721.757 Section 721.757 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.757 Polyoxyalkylene substituted aromatic azo colorant. (a) Chemical... as polyoxyalkylene substituted aromatic azo colorant (PMN P-92-1131) is subject to reporting...

  15. Benzene alkylation with long chain olefins catalyzed by ionic liquids: a review

    Institute of Scientific and Technical Information of China (English)

    Congzhen QIAO; Yonghong CAI; Quanhui GUO

    2008-01-01

    The introduction of ionic liquids to alkylation process gives a choice for "green production" in the pet-rochemical and detergent industry.A lot of papers and patents have been published using chloroaluminate ionic liquid as a novel catalyst for alkylation with high reactivity and easy separation from reactants.These included the acid-ity,characterization,determination and catalysis technolo-gies in batch and continuous operation mode for different scales.According to published data and several results of pilot alkylation,including the authors' experience,the pro-spect of chloroaluminate ionic liquids for commercials was also discussed.It has been pointed out that there still are many difficulties and challenges to be overcome for com-mercial application of the ionic liquid catalyst.

  16. Amine synthesis via iron-catalysed reductive coupling of nitroarenes with alkyl halides.

    Science.gov (United States)

    Cheung, Chi Wai; Hu, Xile

    2016-01-01

    (Hetero)Aryl amines, an important class of organic molecules in medicinal chemistry, are most commonly synthesized from anilines, which are in turn synthesized by hydrogenation of nitroarenes. Amine synthesis directly from nitroarenes is attractive due to improved step economy and functional group compatibility. Despite these potential advantages, there is yet no general method for the synthesis of (hetero)aryl amines by carbon-nitrogen cross-coupling of nitroarenes. Here we report the reductive coupling of nitroarenes with alkyl halides to yield (hetero)aryl amines. A simple iron catalyst enables the coupling with numerous primary, secondary and tertiary alkyl halides. Broad scope and high functional group tolerance are demonstrated. Mechanistic study suggests that nitrosoarenes and alkyl radicals are involved as intermediates. This new C-N coupling method provides general and step-economical access to aryl amines. PMID:27515391

  17. Synthesis of a new conjugated polymer for DNA alkylation and gene regulation.

    Science.gov (United States)

    Nie, Chenyao; Zhu, Chunlei; Feng, Liheng; Lv, Fengting; Liu, Libing; Wang, Shu

    2013-06-12

    A new polyfluorene derivative containing pendent alkylating chlorambucil (PFP-Cbl) was synthesized and characterized. Under direct incubation with DNA in vitro, PFP-Cbl could undergo an efficient DNA alkylating reaction and induce DNA cross-linking. In vitro transcription and translation experiment exhibited that the PFP-Cbl significantly down-regulated the gene expression of luciferase reporter plasmid. The down-regulation of gene expression was also verified through the transfection experiment of p-EGFP plasmid, which showed decreased green fluorescent protein (GFP) in cells. Meanwhile, the self-luminous property of PFP-Cbl could make it able to trace the internalized PFP-Cbl and plasmid complexes resulted from cross-linking in cells by fluorescent microscopy. Combining the features of alkylating function, multivalent binding sites, and fluorescent characteristics, PFP-Cbl provides a new insight in the area of gene regulation and extends the new applications of conjugated polymers (CPs). PMID:23548104

  18. Electron-Exchange Reactions of Aromatic Molecules

    International Nuclear Information System (INIS)

    A large body of information is available on the rates and mechanisms of inorganic electron-exchange processes. In contrast, purely organic systems have received only minor attention. The homogeneous electron-exchange rates (kexc) and the heterogeneous rate constants for the electrode reaction (kel) have been measured only for a few hydrocarbons. We have measured kexc for a variety of aromatic systems including hydrocarbons, quinones and nitro compounds. These measurements have been carried out via electron paramagnetic resonance (EPR) line broadening measurements on mixtures of radical ions and their parent compounds. We have been able to measure kexc with a precision that allows detection of small differences presumably due to molecular structure and environment. Hydrocarbon systems like anthracene/anthracene anion are very rapid with kexc values of ca. 108-109 litres mole-1 sec-1. Some substituted aromatics like quinones and nitriles are also quite rapid. However, when a strong electron acceptor function is present like a nitro group in nitrobenzene, the value of kexc decreases by a factor of 10. It is possible to correlate changes in kexc in the nitrobenzene series with the unpaired electron density in terms of the 14N coupling constants of the EPR spectra. Further, the nitro aromatic series show very large variations in kexc with the solvent system. These changes can be correlated with recent studies of the solvation effect on hyperfine coupling constants. Marcus has reviewed recently chemical and electrochemical electron-transfer theory and suggested correlations between kexc and kel. We have measured kel especially for the nitrobenzene system under conditions which are as nearly identical experimentally to the EPR studies as possible. The electrochemical investigations were carried out by a steady-state d.c. method to eliminate some of the uncertainties inherent in electrochemical relaxation techniques. Rotated disc electrodes at low temperatures were used

  19. Global modeling of the C1-C3 alkyl nitrates using STOCHEM-CRI

    Science.gov (United States)

    Khan, M. A. H.; Cooke, M. C.; Utembe, S. R.; Morris, W. C.; Archibald, A. T.; Derwent, R. G.; Jenkin, M. E.; Orr-Ewing, A. J.; Higgins, C. M.; Percival, C. J.; Leather, K. E.; Shallcross, D. E.

    2015-12-01

    The atmospheric global budget and distribution of C1-C3 alkyl nitrates have been investigated using a global three-dimensional chemistry transport model, STOCHEM-CRI. Alkyl nitrates (RONO2) are significant NOx reservoir species and the more detailed VOC oxidation mechanism (CRI v2-R5) leads to greater photochemical production. RONO2 are significant sources of NOx in regions remote from NOx sources. The study shows that the global burden and the atmospheric life-time of C1-C3 alkyl nitrates are 113 Gg and 9-10 days, respectively, which are in excellent agreement with estimates established by previous studies. The abundance of alkyl nitrates have been found to be higher in the continental atmosphere, with CH3ONO2 mixing ratios up to 20 ppt over the Amazon rainforest. Up to 15, 10, 2, and 5 ppt of modelled CH3ONO2, C2H5ONO2, n-C3H7ONO2 and i-C3H7ONO2 have been found in the northern hemisphere over regions with large anthropogenic emissions of NOx and VOCs. The combination of atmospheric production and long-range transport led to high alkyl nitrate levels at high latitudes. The model performance for C1-C3 alkyl nitrates was established using observations from nine flights and nine field campaigns. The comparison shows a tendency towards model under-prediction of the observations, particularly in the southern hemispheric marine boundary layer, possibly due to the absence of oceanic production mechanisms and air-sea exchange processes in the model. The discrepancies between model and observed seasonal cycles, especially of CH3ONO2, in both hemispheres are discussed.

  20. Temporal variability, sources, and sinks of C1-C5 alkyl nitrates in coastal New England

    Directory of Open Access Journals (Sweden)

    B. C. Sive

    2010-02-01

    Full Text Available Seven C1-C5 alkyl nitrates were measured both on the mainland and off the coast of New Hampshire using gas chromatographic techniques. Five separate data sets are presented to characterize the seasonal and diurnal trends and the major sources and loss processes of these compounds. Based on in situ measurements conducted at the University of New Hampshire (UNH Atmospheric Observing Station at Thompson Farm (TF located in southeast NH during winter (January–February 2002, summer (June–August 2002, summer (July–August 2004, and on daily canister samples collected at midday from January 2004–February 2008, the median total alkyl nitrate mixing ratio (ΣRONO2 was 23–25 pptv in winter and 14–16 pptv in summer. During summers 2002 and 2004, MeONO2 decreased overnight and reached minimum hourly average mixing ratios in the early morning. Comparison with wind speed and trace gas trends suggested that dry deposition contributed to the early morning MeONO2 minimum which is a previously unaccounted for removal mechanism. The mean dry deposition rate and velocity of MeONO2 was estimated to be −0.5 nmol m−2 hr−1 and 0.13 cm s−1, respectively. Results from ambient air and surface seawater measurements made onboard the NOAA R/V Ronald H. Brown in the Gulf of Maine during the 2002 New England Air Quality Study and from ambient canister samples collected throughout the Great Bay estuary in August 2003 are also presented. Comparisons between the alkyl nitrate trends with anthropogenic and marine tracers suggest that a marine source of alkyl nitrates is not significant in coastal New England. Given the apparent prominence of a secondary source, comparisons between observed and predicted alkyl nitrate/parent hydrocarbon ratios were made which demonstrated that background mixing ratios have a continuous and prevalent influence on the alkyl nitrate distribution.

  1. Suppression of alkylating agent induced cell transformation and gastric ulceration by low-dose alkylating agent pretreatment

    International Nuclear Information System (INIS)

    Highlights: •Low-dose MNNG pretreatment suppresses high-dose MNNG induced in vitro transformation. •Gastric ulcers induced by high-dose MNNG decreased after low-dose MNNG pretreatment. •Efficacy of low-dose MNNG related to resistance of mutation and oxidative stress. -- Abstract: Exposure to mild stress by chemicals and radiation causes DNA damage and leads to acquired stress resistance. Although the linear no-threshold (LNT) model of safety assessment assumes risk from any dose, evidence from radiological research demonstrates a conflicting hormetic phenomenon known as the hormesis effect. However, the mechanisms underlying radiation hormesis have not yet been clarified, and little is known about the effects of low doses of chemical carcinogens. We analyzed the efficacy of pretreatment with low doses of the alkylating agent N-methyl-N′-nitro-N-nitrosoguanidine (MNNG) on the subsequent induction of cell transformation and gastric ulceration by high-dose MNNG. We used an in vitro Balb/3T3 A31-1-1 cell transformation test and monitored the formation of gastric ulcers in 5-week-old male ICR mice that were administered MNNG in drinking water. The treatment concentrations of MNNG were determined by the cell survival rate and past reports. For low-dose in vitro and in vivo experiments, MNNG was used at 0.028 μM, and 2.8 μg/mL, respectively. The frequency of cell transformation induced by 10 μm MNNG was decreased by low-dose MNNG pretreatment to levels similar to that of spontaneous transformation. In addition, reactive oxygen species (ROS) and mutation frequencies induced by 10 μm MNNG were decreased by low-dose MNNG pretreatment. Importantly, low-dose MNNG pretreatment had no effect on cell proliferation. In vivo studies showed that the number of gastric ulcers induced by 1 mg/mL MNNG decreased after low-dose MNNG pretreatment. These data indicate that low-dose pretreatment with carcinogens may play a beneficial role in the prevention of chemical toxicity

  2. Active-site alkylation destabilizes human O6-alkylguanine DNA alkyltransferase

    OpenAIRE

    Rasimas, Joseph J.; Dalessio, Paula A.; Ropson, Ira J; Pegg, Anthony E.; Fried, Michael G.

    2004-01-01

    O6-alkylguanine-DNA alkyltransferase (AGT) repairs pro-mutagenic O6-alkylguanine and O4-alkylthymine lesions in DNA. The alkylated form of the protein is not reactivated; instead, it is rapidly ubiquitinated and degraded. Here, we show that alkylation destabilizes the native fold of the protein by 0.5–1.2 kcal/mole and the DNA-binding function by 0.8–1.4 kcal/mole. On this basis, we propose that destabilization of the native conformational ensemble acts as a signal for ubiquitination.

  3. Methyl phosphotriesters in alkylated DNA are repaired by the Ada regulatory protein of E. coli.

    OpenAIRE

    McCarthy, T.V.; Lindahl, T

    1985-01-01

    The E. coli ada+ gene product that controls the adaptive response to alkylating agents has been purified to apparent homogeneity using an overproducing expression vector system. This 39 kDa protein repairs 0(6)-methylguanine and 0(4)-methylthymine residues in alkylated DNA by transfer of the methyl group from the base to a cysteine residue in the protein itself. The Ada protein also corrects one of the stereoisomers of methyl phosphotriesters in DNA by the same mechanism, while the other isom...

  4. Photoalignment efficiency enhancement of polyimide alignment layers by alkyl-amine vapor treatment

    Science.gov (United States)

    Sakamoto, Kenji; Usami, Kiyoaki; Miki, Kazushi

    2014-08-01

    We have succeeded in enhancing the photoalignment efficiency of polyimide containing azobenzene in the backbone structure by exposing the corresponding precursor (polyamic acid: Azo-PAA) film to alkyl-amine vapor prior to photoalignment. The Azo-PAA film absorbed alky-amines and swelled by 300%. The photoinduced rotation of the Azo-PAA backbone structure occurred more easily in the swollen film. Most of the alkyl-amines in the swollen film desorbed during thermal imidization. As a result of the photoalignment efficiency enhancement, we also succeeded in expanding the controllable pretilt angle range of liquid crystals up to 38° without the appearance of threadlike disclination loops.

  5. Efficient SN2 fluorination of primary and secondary alkyl bromides by copper(I) fluoride complexes

    KAUST Repository

    Liu, Yanpin

    2013-11-11

    Copper(I) fluoride complexes ligated by phenanthroline derivatives have been synthesized and structurally characterized by X-ray crystallography. These complexes adopt as either ionic or neutral forms in the solid state, depending on the steric bulkiness of the substituent groups on the phenanthroline ligands. These complexes react with primary and secondary alkyl bromides to produce the corresponding alkyl fluorides in modest to good yields. This new method is compatible with a variety of important functional groups such as ether, thioether, amide, nitrile, methoxyl, hydroxyl, ketone, ester, and heterocycle moieties. © 2013 American Chemical Society.

  6. Palladium catalysed asymmetric alkylation of benzophenone Schiff base glycine esters in ionic liquids

    Indian Academy of Sciences (India)

    Dae Hyun Kim; Jin Kyu Im; Dae Won Kim; Minserk Cheong; Hoon Sik Kim; Deb Kumar Mukherjee

    2011-07-01

    Asymmetric alkyl substitution of various benzophenone Schiff base substrates under biphasic conditions proceeded using optically active Palladium(II) complexes. The corresponding products were obtained in high yields but with moderate enantiomeric excess (ee). Addition of specific ionic liquids to the reaction medium enhanced reactivity and selectivity for phase transfer catalytic (PTC) glycine alkylation. It has been found that there is an anionic influence of the ionic liquids that modify the steric environment around the enolate ion. A computer-assisted molecular design of enantioselective phase-transfer catalysis with the palladium complex and the ionic liquid has been done.

  7. A study on synthesis and oxidation mechanism of mono-alkyl phosphate

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Oxidation of white phosphorus by peroxides to produce mono-alkyl phosphate in the alcoholic solution has been studied under non-and catalytic conditions. In this paper,the mechanism of the oxidation process was analyzed. The content of mono-alkyl phosphate in the product is affected by different types of alcoholic solution and peroxide solvent. The result shows the availability of the following order for the activity of the peroxide solvent and alcoholic solutions-tert-butyl hydroperoxide>(di) benzoyl perox...

  8. Synthesis, properties and self-organization of meso-arylporphyrins with higher alkyl substituents

    Science.gov (United States)

    Bragina, N. A.; Zhdanova, K. A.; Mironov, A. F.

    2016-05-01

    The review summarizes published data on the methods for preparation of meso-arylporphyrins with higher alkyl substituents. The methods for creation of self-organized nanostructures based on these compounds and the data on their applications are presented. Approaches to the synthesis of functionalized lipophilic and amphiphilic meso-arylporphyrins are discussed. The ways and driving forces for the formation of supramolecular porphyrin arrays in solutions and on the substrate surface are considered. The prospects of using alkyl porphyrin derivatives for the design of nanomaterials are shown. The bibliography includes 204 references.

  9. Practical Ni-Catalyzed Aryl-Alkyl Cross-Coupling of Secondary Redox-Active Esters.

    Science.gov (United States)

    Cornella, Josep; Edwards, Jacob T; Qin, Tian; Kawamura, Shuhei; Wang, Jie; Pan, Chung-Mao; Gianatassio, Ryan; Schmidt, Michael; Eastgate, Martin D; Baran, Phil S

    2016-02-24

    A new transformation is presented that enables chemists to couple simple alkyl carboxylic acids with aryl zinc reagents under Ni-catalysis. The success of this reaction hinges on the unique use of redox-active esters that allow one to employ such derivatives as alkyl halides surrogates. The chemistry exhibits broad substrate scope and features a high degree of practicality. The simple procedure and extremely inexpensive nature of both the substrates and pre-catalyst (NiCl2·6H2O, ca. $9.5/mol) bode well for the immediate widespread adoption of this method. PMID:26835704

  10. Neighbor-directed histidine N(τ) alkylation. A route to imidazolium-containing phosphopeptide macrocycles

    Energy Technology Data Exchange (ETDEWEB)

    Qian, Wen-Jian [National Cancer Inst., Frederick, MD (United States); Park, Jung-Eun [National Cancer Inst., Bethesda, MD (United States); Grant, Robert [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Lai, Christopher C. [National Cancer Inst., Frederick, MD (United States); Kelley, James A. [National Cancer Inst., Frederick, MD (United States); Yaffe, Michael B. [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Lee, Kyung S. [National Cancer Inst., Bethesda, MD (United States); Burke, Terrence R. [National Cancer Inst., Frederick, MD (United States)

    2015-07-07

    Our recently discovered, selective, on-resin route to N(τ)-alkylated imidazolium-containing histidine residues affords new strategies for peptide mimetic design. In this, we demonstrate the use of this chemistry to prepare a series of macrocyclic phosphopeptides, in which imidazolium groups serve as ring-forming junctions. These cationic moieties subsequently serve to charge-mask the phosphoamino acid group that directed their formation. Furthermore, neighbor-directed histidine N(τ)-alkylation opens the door to new families of phosphopeptidomimetics for use in a range of chemical biology contexts.

  11. Alkylation mechanism of benzene with 1-dodecene catalyzed by Et3NHCl-AlCl3

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The isotope exchange method was employed to investigate the catalytic mechanism of ionic liquid in alkylation of benzenes with olefins.It is proposed that alkylation was induced by the Lewis acid AlCl3 which attracted π electrons of 1-dodecene to shift toward 1-carbon,thus forming a carbonium ion.The carbonium ion further reacted with benzenes to form a complex.Due to unstabilit of the complex,a deuterated ring proton was transferred into an electronegative 1-carbon of the side chain to substitute for the AlCl3,accordingly 2-phenyldodecane was generated.

  12. Effects of alkyl chain positioning on conjugated polymer microstructure and field-effect mobilities

    KAUST Repository

    Schroeder, Bob C.

    2015-07-02

    Solubilizing alkyl chains play a crucial role in the design of semiconducting polymers because they define the materials solubility and processability as well as both the crystallinity and solid-state microstructure. In this paper, we present a scarcely explored design approach by attaching the alkyl side chains on one side (cis-) or on both sides (trans-) of the conjugated backbone. We further investigate the effects of this structural modification on the solid-state properties of the polymers and on the charge-carrier mobilities in organic thin-film transistors. Copyright © Materials Research Society 2015

  13. High-Throughput Screening of the Asymmetric Decarboxylative Alkylation Reaction of Enolate-Stabilized Enol Carbonates

    KAUST Repository

    Stoltz, Brian

    2010-06-14

    The use of high-throughput screening allowed for the optimization of reaction conditions for the palladium-catalyzed asymmetric decarboxylative alkylation reaction of enolate-stabilized enol carbonates. Changing to a non-polar reaction solvent and to an electron-deficient PHOX derivative as ligand from our standard reaction conditions improved the enantioselectivity for the alkylation of a ketal-protected,1,3-diketone-derived enol carbonate from 28% ee to 84% ee. Similar improvements in enantioselectivity were seen for a β-keto-ester derived- and an α-phenyl cyclohexanone-derived enol carbonate.

  14. Studies on Phase Behavior of Alkyl Polyglucoside Based on Microemulsions with Modified Fishlike Phase Diagram

    Institute of Scientific and Technical Information of China (English)

    Jin Ling CHAI; Gan Zuo LI; Zhao Yu DIAO; Gao Yong ZHANG

    2004-01-01

    The three-phase behavior in the quaternary system of an alkyl (C8/10- or C12/14-) polyglucoside / 1-butanol / n-octane / water has been studied at 40 ℃ with the modified fishlike phase diagram, which is presented by us for the first time. The mass fraction of 1-butanol in the hydrophile-lipophile balanced interfacial layer, AS, the coordinates of the start point B and the end point E of the phase diagram, and the solubilities of alkyl polyglucoside and 1-butanol in n-octane phase were calculated. The solubilization of the microemulsion was also discussed.

  15. Replacing Conventional Carbon Nucleophiles with Electrophiles: Nickel-Catalyzed Reductive Alkylation of Aryl Bromides and Chlorides

    OpenAIRE

    Everson, Daniel A.; Jones, Brittany A.; Weix, Daniel J.

    2012-01-01

    A general method is presented for the synthesis of alkylated arenes by the chemoselective combination of two electrophilic carbons. Under the optimized conditions, a variety of aryl and vinyl bromides are reductively coupled with alkyl bromides in high yields. Under similar conditions, activated aryl chlorides can also be coupled with bromoalkanes. The protocols are highly functional-group tolerant (−OH, −NHTs, −OAc, −OTs, −OTf, −COMe, −NHBoc, −NHCbz, −CN, −SO2Me), and the reactions are assem...

  16. Pro-aromatic and anti-aromatic π-conjugated molecules: an irresistible wish to be diradicals

    KAUST Repository

    Zeng, Zebing

    2015-01-01

    © 2015 The Royal Society of Chemistry. Aromaticity is an important concept to understand the stability and physical properties of π-conjugated molecules. Recent studies on pro-aromatic and anti-aromatic molecules revealed their irresistible tendency to become diradicals in the ground state. Diradical character thus becomes another very important concept and it is fundamentally correlated to the physical (optical, electronic and magnetic) properties and chemical reactivity of most of the organic optoelectronic materials. Molecules with distinctive diradical character show unique properties which are very different from those of traditional closed-shell π-conjugated systems, and thus they have many potential applications in organic electronics, spintronics, non-linear optics and energy storage. This critical review first introduces the fundamental electronic structure of Kekulé diradicals within the concepts of anti-aromaticity and pro-aromaticity in the context of Hückel aromaticity and diradical character. Then recent research studies on various stable/persistent diradicaloids based on pro-aromatic and anti-aromatic compounds are summarized and discussed with regard to their synthetic chemistry, physical properties, structure-property relationships and potential material applications. A summary and personal perspective is given at the end.

  17. Neutron Scattering of Aromatic and Aliphatic Liquids

    Science.gov (United States)

    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

  18. Neutron Scattering of Aromatic and Aliphatic Liquids.

    Science.gov (United States)

    Falkowska, Marta; Bowron, Daniel T; Manyar, Haresh G; Hardacre, Christopher; Youngs, Tristan G A

    2016-07-01

    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

  19. Muonium addition reactions to aromatic solutes

    International Nuclear Information System (INIS)

    Reaction rate constants of 0.3 to 1.1 x 10sup(10) Msup(-1) ssup(-1) were determined for the reaction of muonium (μsup(+)esup(-),Mu) with seven aromatic solutes in dilute aqueous solution at approximately 295K. The reaction was deduced to be that of addition to the benzene ring to form cyclohexadienyl radicals. On comparison with the analogous H-atom reactions, the kinetic isotope effects were generally about three, equal to the mean thermal velocity ratio of Mu/H. When analyzed through the Hammett equation there were serious discontinuities but a rho value of +0.6 was deduced, not inconsistent with attack by a mildly electron-donating neutral atom forming only free radical intermediates

  20. Naturally occurring antifungal aromatic esters and amides

    International Nuclear Information System (INIS)

    During the search of antifungal natural products from terrestrial plants, a new long chained aromatic ester named grandiflorate along with spatazoate from Portulaca grandiflora and N-[2-methoxy-2-(4-methoxyphenyl) ethyl]-trans-cinnamide and aegeline from Solanum erianthum of Nigeria were isolated and tested against six fungal species. The known constituents have not been reported so far from mentioned investigated plants. Structures of the isolated compounds were elucidated with the aid of spectroscopic techniques including two dimensional NMR experiments. Among the compounds, the esters found more potent than amides against Candida albicans and Aspergillus flavus. The new compound grandiflorate gave response against all tested fungal species while aegeline was found to give lowest inhibition during this study. (author)

  1. ANTIEMETIC ACTIVITY OF SOME AROMATIC PLANTS

    Directory of Open Access Journals (Sweden)

    Hasan MuhammadMohtasheemul

    2012-02-01

    Full Text Available Current study was conducted to explore the antiemetic activity of ten aromatic medicinal plants viz., Carissa carandus L. (fruits, Chichorium intybus L (flowers, Cinnamum tamala L (leaves, Curcuma caesia Roxb (rhizomes, Lallemantia royleana Benth (leaves, Matricaria chamomila L (flowers, Piper longum L (fruits, Piper methysticum G. Forst (fruits, Piper nigrum Linn. (fruits and Syzygium aromaticum (Linn. Merr. & Perry (flowering buds was studied using chick emetic model. The ethanol extracts of these plants were administered at 150 mg/kg body weight orally. Domperidone was given at 100 mg/kg as a reference drug. All the extracts decrease in retches induced by copper sulphate pentahydrate given orally at 50 mg/kg body weight and showed comparable antiemetic activity with domperidone. Compound targeted antiemetic activity is further suggested.

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

    Science.gov (United States)

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

    1956-01-01

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

  3. Environmental Remediation: Removal of polycyclic aromatic hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Nkansah, Marian Asantewah

    2012-11-15

    Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous persistent semi-volatile organic compounds. They are contaminants that are resistant to degradation and can remain in the environment for long periods due to their high degree of conjugation, and aromaticity. PAHs are present in industrial effluents as products of incomplete combustion processes of organic compounds. Petroleum, coal and shale oil contain extremely complex mixtures of these PAHs, and their transport and refining process can also result in the release of PAHs. It is therefore prudent that such effluents are treated before discharge into the environment. In this project, different approaches to the treatment of PAHs have been investigated. Hydrous pyrolysis has been explored as a potential technique for degrading PAHs in water using anthracene as a model compound. The experiments were performed under different conditions of temperature, substrate, redox systems and durations. The conditions include oxidising systems comprising pure water, hydrogen peroxide and Nafion-SiO2 solid catalyst in water; and reducing systems of formic acid and formic acid / Nafion-SiO2 / Pd-C catalysts to assess a range of reactivities. Products observed in GCMS analysis of the extract from the water phase include anthrone, anthraquinone, xanthone and multiple hydro-anthracene derivatives (Paper I). In addition a modified version of the Nafion-SiO2 solid catalyst in water oxidising system was tested; and reducing systems of formic acid and formic acid / Nafion-SiO2 / Pd-C catalysts were adopted for the conversion of a mixture of anthracene, fluorene and fluoranthene. The rate of conversion in the mixture was high as compared to that of only anthracene (Paper II). Also the use of LECA (Lightweight expanded clay aggregates) as an adsorbent (Paper III) for PAHs (phenanthrene, fluoranthene and pyrene) removal from water has been.(Author)

  4. Hot foam for weed control-Do alkyl polyglucoside surfactants used as foaming agents affect the mobility of organic contaminants in soil?

    Science.gov (United States)

    Cederlund, H; Börjesson, E

    2016-08-15

    Use of alkyl polyglucosides (APGs) as a foaming agent during hot water weed control may influence the environmental fate of organic contaminants in soil. We studied the effects of the APG-based foaming agent NCC Spuma (C8-C10) on leaching of diuron, glyphosate, and polycyclic aromatic hydrocarbons (PAHs) in sand columns. We also examined how APG concentration affected the apparent water solubility and adsorption of the herbicides and of the PAHs acenaphthene, acenaphthylene and fluorene. Application of APGs at the recommended concentration of 0.3% did not significantly affect leaching of any of the compounds studied. However, at a concentration of 1.5%, leaching of both diuron and glyphosate was significantly increased. The increased leaching corresponded to an increase in apparent water solubility of diuron and a decrease in glyphosate adsorption to the sand. However, APG addition did not significantly affect the mobility of PAHs even though their apparent water solubility was increased. These results suggest that application of APG-based foam during hot water weed control does not significantly affect the mobility of organic contaminants in soil if used according to recommendations. Moreover, they suggest that APGs could be useful for soil bioremediation purposes if higher concentrations are used. PMID:27149400

  5. Copper(I)-catalyzed carbon-halogen bond-selective boryl substitution of alkyl halides bearing terminal alkene moieties

    OpenAIRE

    Iwamoto, Hiroaki; Kubota, Koji; Yamamoto, Eiji; Ito, Hajime

    2015-01-01

    The selective boryl substitution of alkyl halides bearing terminal C=C double bonds has been achieved using a copper(I)/tricyclohexylphosphine or copper(I)/o-diphenylphosphinophenol catalyst. This reaction represents a useful complementary approach to conventional procedures for the hydroboration of C=C double bonds or the borylative cyclization of alkyl halides bearing terminal alkenes.

  6. 40 CFR 721.3130 - Sulfuric acid, mono-C9-11-alkyl esters, sodium salts.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Sulfuric acid, mono-C9-11-alkyl esters... Specific Chemical Substances § 721.3130 Sulfuric acid, mono-C9-11-alkyl esters, sodium salts. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as...

  7. Solid-state fluorescence property and crystal structure of biphenyl derivatives with carboxyl and n-alkyl groups

    Energy Technology Data Exchange (ETDEWEB)

    Imai, Yoshitane, E-mail: y-imai@apch.kindai.ac.j [Department of Applied Chemistry, Faculty of Science and Engineering, Kinki University, 3-4-1 Kowakae, Higashi-Osaka, Osaka 577-8502 (Japan); Kamon, Kensaku [Department of Applied Chemistry, Faculty of Science and Engineering, Kinki University, 3-4-1 Kowakae, Higashi-Osaka, Osaka 577-8502 (Japan); Tajima, Nobuo [First-Principles Simulation Group, Computational Materials Science Center, NIMS, Sengen, Tsukuba, Ibaraki 305-0047 (Japan); Kinuta, Takafumi [Department of Applied Chemistry, Faculty of Science and Engineering, Kinki University, 3-4-1 Kowakae, Higashi-Osaka, Osaka 577-8502 (Japan); Sato, Tomohiro [JST ERATO-SORST Kuroda Chiromorphology Team, 4-7-6 Komaba, Meguro-ku, Tokyo 153-0041 (Japan); Kuroda, Reiko [JST ERATO-SORST Kuroda Chiromorphology Team, 4-7-6 Komaba, Meguro-ku, Tokyo 153-0041 (Japan); Department of Life Sciences, Graduate School of Arts and Sciences, University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo 153-8902 (Japan); Matsubara, Yoshio, E-mail: y-matsu@apch.kindai.ac.j [Department of Applied Chemistry, Faculty of Science and Engineering, Kinki University, 3-4-1 Kowakae, Higashi-Osaka, Osaka 577-8502 (Japan)

    2010-06-15

    By introducing carboxyl and n-alkyl groups into a biphenyl molecule, we can increase the photoluminescence quantum yields of biphenyl derivatives in the solid state. The solid-state fluorescence maxima (lambda{sub em}) of 4-biphenylcarboxylic acid derivatives change according to the n-alkyl group introduced.

  8. Oxidative stability of fatty acid alkyl esters: a review.

    Directory of Open Access Journals (Sweden)

    Michal Angelovič

    2015-12-01

    Full Text Available The purpose of this study was to investigate and to process the current literary knowledge of the physico-chemical properties of vegetable oil raw used for biodiesel production in terms of its qualitative stability. An object of investigation was oxidative stability of biodiesel. In the study, we focused on the qualitative physico-chemical properties of vegetable oils used for biodiesel production, oxidative degradation and its mechanisms, oxidation of lipids, mechanisms of autooxidation, effectivennes of different synthetic antioxidants in relation to oxidative stability of biodiesel and methods of oxidative stability determination. Knowledge of the physical and chemical properties of vegetable oil as raw material and the factors affecting these properties is critical for the production of quality biodiesel and its sustainability. According to the source of oilseed, variations in the chemical composition of the vegetable oil are expressed by variations in the molar ratio among different fatty acids in the structure. The relative ratio of fatty acids present in the raw material is kept relatively constant after the transesterification reaction. The quality of biodiesel physico-chemical properties is influenced by the chain length and the level of unsaturation of the produced fatty acid alkyl esters. A biodiesel is thermodynamically stable. Its instability primarily occurs from contact of oxygen present in the ambient air that is referred to as oxidative instability. For biodiesel is oxidation stability a general term. It is necessary to distinguish ‘storage stability' and ‘thermal stability', in relation to oxidative degradation, which may occur during extended periods of storage, transportation and end use. Fuel instability problems can be of two related types, short-term oxidative instability and long-term storage instability. Storage instability is defined in terms of solid formation, which can plug nozzles, filters, and degrade engine

  9. Measurements of photo-oxidation products from the reaction of a series of alkyl-benzenes with hydroxyl radicals during EXACT using comprehensive gas chromatography

    Directory of Open Access Journals (Sweden)

    J. F. Hamilton

    2003-01-01

    Full Text Available Photo-oxidation products from the reaction of a series of alkyl-benzenes, (benzene, toluene, p-xylene and 1,3,5-trimethyl-benzene with hydroxyl radicals in the presence of NOx have been investigated using comprehensive gas chromatography (GCxGC. A GCxGC system has been developed which utilises valve modulation and independent separations as a function of both volatility and polarity. A number of carbonyl-type compounds were identified during a series of reactions carried out at the European Photoreactor (EUPHORE, a large volume outdoor reaction chamber in Valencia, Spain. Experiments were carried as part of the EXACT project (Effects of the oXidation of Aromatic Compounds in the Troposphere. Two litre chamber air samples were cryo-focused, with a sampling frequency of 30 minutes, allowing the evolution of species to be followed over oxidation periods of 3-6 hours. To facilitate product identification, several carbonyl compounds, which were possible products of the photo-oxidation, were synthesised and used as reference standards. For toluene reactions, observed oxygenated intermediates found included the co-eluting pair a-angelicalactone/4-oxo-2-pentenal, maleic anhydride, citraconic anhydride, benzaldehyde and p-methyl benzoquinone. In the p-xylene experiment, the products identified were E/Z-hex-3-en-2,5-dione and citraconic anhydride. For 1,3,5-TMB reactions, the products identified were 3,5-dimethylbenzaldehyde, 3,5-dimethyl-3H-furan-2-one and 3-methyl-5-methylene-5H-furan-2-one. Preliminary quantification was carried out on identified compounds using liquid standards. Comparison of FTIR and GCxGC for the measurement of the parent aromatics generally showed good agreement. Comparison of the concentrations observed by GCxGC to concentration-time profiles simulated using the Master Chemical Mechanism, MCMv3, demonstrates that this mechanism significantly over-predicts the concentrations of many product compounds and highlights the

  10. Alkane, terpene and polycyclic aromatic hydrocarbon geochemistry of the Mackenzie River and Mackenzie shelf: Riverine contributions to Beaufort Sea coastal sediment

    Science.gov (United States)

    Yunker, Mark B.; Macdonald, Robie W.; Cretney, Walter J.; Fowler, Brian R.; McLaughlin, Fiona A.

    1993-07-01

    To study the largest source of river sediment to the Arctic Ocean, we have collected suspended particulates from the Mackenzie River in all seasons and sediments from the Mackenzie shelf between the river mouth and the shelf edge. These samples have been analyzed for alkanes, triterpenes and polycyclic aromatic hydrocarbons (PAHs). We found that naturally occurring hydrocarbons predominate in the river and on the shelf. These hydrocarbons include biogenic alkanes and triterpenes with a higher plant/peat origin, diagenetic PAHs from peat and plant detritus, petrogenic alkanes, triterpenes and PAHs from oil seeps and/or bitumens and combustion PAHs that are likely relict in peat deposits. Because these components vary independently, the season is found to strongly influence the concentration and composition of hydrocarbons in the Mackenzie River. While essentially the same pattern of alkanes, diagenetic hopanes and alkyl PAHs is observed in all river and most shelf sediment samples, alkane and triterpene concentration variations are strongly linked to the relative amount of higher plant/peat material. Polycyclic aromatic hydrocarbon molecular-mass profiles also appear to be tied primarily to varying proportions of peat, with an additional petrogenic component which is most likely associated with lithic material mobilized by the Mackenzie River at freshet. Consistent with the general lack of alkyl PAHs in peat, the higher PAHs found in the river are probably derived from forest and tundra fires. A few anthropogenic/pyrogenic compounds are manifest only at the shelf edge, probably due to a weakening of the river influence. We take this observation of pyrogenic PAHs and the pronounced source differences between two sediment samples collected at the shelf edge as evidence of a transition from dominance by the Mackenzie River to the geochemistry prevalent in Arctic regions far removed from major rivers.

  11. The future role of aromatics in refining and petrochemistry. Proceedings of the DGMK-Conference (Authors' manuscripts)

    Energy Technology Data Exchange (ETDEWEB)

    Emig, G.; Rupp, M.; Weitkamp, J. [eds.

    1999-07-01

    Topic of this conference has been the furure role of aromatics in the refinign industry. The articles deal with the following topics: Refining; legal aspects in the aromatics market; transportation fuels; dearomatization; catalytic reforming and aromatics; separation processes for aromatics; oxidation and ammoxidation of aromatics; electrophilic substitution of aromatics; hydrogenation of benzene; zeolites. (orig./sr)

  12. Binary functionalization of H:Si(111) surfaces by alkyl monolayers with different linker atoms enhances monolayer stability and packing.

    Science.gov (United States)

    Arefi, Hadi H; Nolan, Michael; Fagas, Giorgos

    2016-05-14

    Alkyl monolayer modified Si forms a class of inorganic-organic hybrid materials with applications across many technologies such as thin-films, fuel/solar-cells and biosensors. Previous studies have shown that the linker atom, through which the monolayer binds to the Si substrate, and any tail group in the alkyl chain, can tune the monolayer stability and electronic properties. In this paper we study the H:Si(111) surface functionalized with binary SAMs: these are composed of alkyl chains that are linked to the surface by two different linker groups. Aiming to enhance SAM stability and increase coverage over singly functionalized Si, we examine with density functional theory simulations that incorporate vdW interactions, a range of linker groups which we denote as -X-(alkyl) with X = CH2, O(H), S(H) or NH(2) (alkyl = C6 and C12 chains). We show how the stability of the SAM can be enhanced by adsorbing alkyl chains with two different linkers, e.g. Si-[C, NH]-alkyl, through which the adsorption energy is increased compared to functionalization with the individual -X-alkyl chains. Our results show that it is possible to improve stability and optimum coverage of alkyl functionalized SAMs linked through a direct Si-C bond by incorporating alkyl chains linked to Si through a different linker group, while preserving the interface electronic structure that determines key electronic properties. This is important since any enhancement in stability and coverage to give more densely packed monolayers will result in fewer defects. We also show that the work function can be tuned within the interval of 3.65-4.94 eV (4.55 eV for bare H:Si(111)). PMID:27109872

  13. Aromatic hydrocarbon concentrations in sediments of Placentia Bay, Newfoundland

    International Nuclear Information System (INIS)

    A study was conducted to examine the potential for contamination of recent sediments with polycyclic aromatic hydrocarbons due to tanker and refinery activity in Placentia Bay, Newfoundland, an area without large local anthropogenic sources of aromatics. Sediment samples were taken from the vicinity of the Come By Chance refinery, Woody Island, Wild Cove, and Port Royal Arm, all in the north end of the bay. The samples were extracted by two methods, dichloromethane extraction of dried sediment for determination of total aromatic hydrocarbon content and hexane extraction of wet sediment for estimation of the bioavailability of hydrocarbons and determination of more volatile compounds. Class analysis of aromatic hydrocarbons was conducted on a NH2 column with detection at 255 nm. Total concentrations of di-tricyclic aromatics were highest at the Woody Island site (0.6 μg/g). The sediments from the Come By Chance site, Wild Cove, and Port Royal Arm sediments contained 0.3, 0.1, and 0.2 μg/g respectively. The hexane extracts from Come By Chance were lowest in di-tricyclic aromatics (0.007 μg/g), with the other sites being equal in concentration (0.01 μg/g). It is evident from the study that aromatic hydrocarbon concentrations in Placentia Bay are elevated in some parts of the bay in the absence of local combustion sources, and that the most likely source is petroleum. 12 refs., 5 figs., 2 tabs

  14. Equilibria and kinetics for H-dependent axial ligation of alkyl(aquo) cobaloximes with aromatic and aliphatic N-donor ligands

    Indian Academy of Sciences (India)

    V Sridhar; D Sudarshan Reddy; N Ravikumar Reddy; S Satyanarayana

    2002-02-01

    Equilibria and kinetics of the reaction of bromomethyl(aquo) cobaloxime with histamine, histidine, glycine and ethyl glycine ester and iodomethyl(aquo) cobaloxime with cyanide, imidazole and substituted imidazoles were studied as a function of H at 25°C, 1.0 M ionic strength (KCl) by spectrophotometry technique. The rate of substitution of H2O varies with the of the incoming ligand, thus establishing the existence of nucleophilic participation of the ligand in the transition state. Dissociation kinetic reactions were also studied as a function of H. Binding and kinetic data were interpreted based on the basicity, steric crowd of the entering ligand and HSAB principle. To compare the rate constants of the entering ligands H independent second-order rate constants were calculated.

  15. 40 CFR 721.642 - Amines, N-(C14-18 and C16-16 unsaturated alkyl)] dipropylene-tri-, tripropylenetetra-, and...

    Science.gov (United States)

    2010-07-01

    ... unsaturated alkyl)] dipropylene-tri-, tripropylenetetra-, and tetrapropylenepenta-. 721.642 Section 721.642... Amines, N-(C14-18 and C16-16 unsaturated alkyl)] dipropylene-tri-, tripropylenetetra-, and... substances amines, N-(C14-18 and C16-18 unsaturated alkyl)] dipropylenetri-, (PMN...

  16. Enzymatic production of alkyl esters through alcoholysis: A critical evaluation of lipases and alcohols

    DEFF Research Database (Denmark)

    Li, Deng; Xu, Xuebing; Gudmundur G, Haraldsson; Wang, Fang

    2005-01-01

    This paper focuses on a detailed evaluation of commercially available immobilized lipases and simple monohydric alcohols for the production of alkyl esters from sunflower oil by enzymatic alcoholysis. Six lipases were tested with seven alcohols, including straight and branched-chain primary and...

  17. A study on synthesis and oxidation mechanism of mono-alkyl phosphate

    Institute of Scientific and Technical Information of China (English)

    Sheng Wang; Shu-yun Yan; Qing-guo Ye

    2009-01-01

    Oxidation of white phosphor, us by peroxides to produce mono-alkyl phosphate in the alcoholic solution has been studied under non-and catalytic conditions. In this paper, the mechanism of the oxidation process was analyzed. The content of mono-alkyl phosphalte in the product is affected by different types of alcoholic solution and peroxide solvent. The result shows the availabulity of the following order for the activity of the peroxide solvent and alcoholic solutions-tert-butyl hydroperoxide>(di) benzoyl peroxide>hydroperoxide; methanol> n-butyl alcohol> phenol. Under optimized reaction conditions: n (a white phosphorus) : n( tert-butyl hydroperoxide) : n (methanol)= 1:10:12, reaction temperature 80 ℃, reaction time 2.5 h, products of 80.0% mono-alkyl phosphonates can be provided when white phosphorus undergoes oxidation by tert-butyl hydroperoxide in the methanol solutions. When Cu (I), and Cn(Ⅱ) complexes are used as catalysts, it is possible to significantly enhance the oxidation of white phosphorus with the increase in the reaction rate. Th'e order for activity of catalysts is Cu(acac)2>Cu (CH3COO)2>Cu (C3 H7COO)2:>CuI>CuCI2. Noticeably, with Cu(acac)2 as catalyst, the selectivity for mono-alkyl phusphonates can reach 95% under adequate reaction conditions.

  18. Radiation chemistry of hydrocarbon and alkyl halide systems. Progress report, August 1, 1980-July 31, 1981

    International Nuclear Information System (INIS)

    The results reported here include new measurements on the four systems proposed for study last year. These are pulse radiolysis of alkyl iodide and perfluoaroalkyl iodide systems; gamma radiolysis of H2-CO mixtures; photochemistry and mass spectrometry of propane. The work accomplished is described

  19. Effect of alkyl-N-phenylcarbamates on photochemical activity of spinach chloroplasts

    International Nuclear Information System (INIS)

    This study is aimed to investigate the effect of alkyl-N-phenylcarbamates on photosynthetic electron transport in spinach chloroplasts, to determine site of action in the photosynthetic apparatus of spinach chloroplasts and to find correlations between their structure and biological activity. (authors)

  20. Selective synthesis of linear alkylbenzene by alkylation of benzene with 1-dodecene over desilicated zeolites

    Czech Academy of Sciences Publication Activity Database

    Aslam, W.; Siddiqui, M. A. B.; Jermy, B. R.; Aitani, A.; Čejka, Jiří; Al-Khattaf, S.

    2014-01-01

    Roč. 227, MAY 2014 (2014), s. 187-197. ISSN 0920-5861 R&D Projects: GA ČR GBP106/12/G015 Institutional support: RVO:61388955 Keywords : zeolites * benzene alkylation * long-chain olefin Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.893, year: 2014

  1. Effect O6-Guanine Alkylation on DNA Flexibility Studied by Comparative Molecular Dynamics Simulations

    Czech Academy of Sciences Publication Activity Database

    Kara, M.; Dršata, Tomáš; Lankaš, Filip; Zacharias, M.

    2015-01-01

    Roč. 103, č. 1 (2015), s. 23-32. ISSN 0006-3525 R&D Projects: GA ČR(CZ) GA14-21893S Institutional support: RVO:61388963 Keywords : DNA damage * DNA alkylation * DNA repair * molecular simulation * molecular dynamics simulation Subject RIV: BO - Biophysics Impact factor: 2.385, year: 2014

  2. Production of poly(alkyl cyanoacrylate)nanoparticles as a coating material that changes wetting property

    Science.gov (United States)

    Alkyl cyanoacrylates have long been used for the synthesis of colloidal nanoparticles. In the involved polymerization reaction, OH- ions derived from dissociation of water have been used as an initiator. In the current research, functional groups on the surface of proteins were utilized as an initia...

  3. Enhanced Synthesis of Alkyl Amino Acids in Miller's 1958 H2S Experiment

    Science.gov (United States)

    Parker, Eric T.; Cleaves, H. James; Callahan, Michael P.; Dworkin, James P.; Glavin, Daniel P.; Lazcano, Antonio; Bada, Jeffrey L.

    2011-01-01

    Stanley Miller's 1958 H2S-containing experiment, which included a simulated prebiotic atmosphere of methane (CH4), ammonia (NH3), carbon dioxide (CO2), and hydrogen sulfide (H2S) produced several alkyl amino acids, including the alpha-, beta-, and gamma-isomers of aminobutyric acid (ABA) in greater relative yields than had previously been reported from his spark discharge experiments. In the presence of H2S, aspariic and glutamic acids could yield alkyl amino acids via the formation of thioimide intermediates. Radical chemistry initiated by passing H2S through a spark discharge could have also enhanced alkyl amino acid synthesis by generating alkyl radicals that can help form the aldehyde and ketone precursors to these amino acids. We propose mechanisms that may have influenced the synthesis of certain amino acids in localized environments rich in H2S and lightning discharges, similar to conditions near volcanic systems on the early Earth, thus contributing to the prebiotic chemical inventory of the primordial Earth.

  4. Preparation of 6,6'-Bisperfluoroalkylated BINOLs and Their Application in Asymmetric Alkylation of Benzaldehyde

    Institute of Scientific and Technical Information of China (English)

    YIN,Yue-Yan(尹月燕); ZHAO,Gang(赵刚); YANG,Gao-Sheng(杨高升); YIN,Wei-Xing(殷卫星)

    2002-01-01

    6,6'-Bis(1H,1H,2H,2H-perfluorooctyl)-BINOL and 6,6'-bis(1H ,1H , 2 H , 2 H- perfluorodecyl ) -BINOL were synthesized through Suzuki coupling reaction and used in fluorous biphase asymmetric alkylation of benzaldehyde. Good enantioselectivity was obtained and the catalysts could be recovered by liquid-liquid extraction.

  5. Alkylation of phenols and acylation 2-methoxynaphthalene over SSZ-33, SSZ-35 and SSZ-42 zeolites

    Czech Academy of Sciences Publication Activity Database

    Vitvarová, Dana; Lupínková, Lenka; Kubů, Martin

    2015-01-01

    Roč. 210, JUL 2015 (2015), s. 133-141. ISSN 1387-1811 R&D Projects: GA ČR GAP106/11/0819 Institutional support: RVO:61388955 Keywords : phenol alkylation * 2-methoxynaphthalene acylation * SSZ-33 Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.453, year: 2014

  6. Presence and sources of anthropogenic perfluorinated alkyl acids in tap-water based beverages

    NARCIS (Netherlands)

    C. Eschauzier; M. Hoppe; M. Schlummer; P. de Voogt

    2012-01-01

    This study investigates the presence and sources of perfluorinated alkyl acids (PFAAs) in tap water and corresponding tap-water based beverages such as coffee and cola collected in the city of Amsterdam, The Netherlands. Exposure pathways studies have shown that low concentrations of PFAA in tap wat

  7. Controlling the reversible thermochromism of polydiacetylene/zinc oxide nanocomposites by varying alkyl chain length.

    Science.gov (United States)

    Chanakul, Amornsak; Traiphol, Nisanart; Traiphol, Rakchart

    2013-01-01

    In this work, polydiacetylene (PDA)/ZnO nanocomposites are successfully fabricated by using three types of monomers with different alkyl chain length, 5,7-hexadecadiynoic acid, 10,12-tricosadiynoic acid, and 10,12-pentacosadiynoic acid. The monomers dispersed in aqueous medium spontaneously assemble onto the surface of ZnO nanoparticles, promoted by strong interfacial interactions. The PDA/ZnO nanocomposites obtained via photopolymerization process are characterized by scanning electron microscopy, laser light scattering, infrared spectroscopy, and uv/vis absorption spectroscopy. The strength of interfacial interactions and morphologies of the nanocomposites are found to vary with alkyl chain length of the monomers. The PDA/ZnO nanocomposites also exhibit rather different thermochromic behaviors compared to their pure PDA counterparts. All nanocomposites show reversible blue/purple color transition upon multiple heating/cooling cycles, while the irreversible blue/red color transition is observed in the systems of pure PDAs. The shortening of alkyl side chain in PDA/ZnO nanocomposites leads to a systematic decrease in their color-transition temperatures. Colors of the nanocomposites at elevated temperature also vary with the alkyl chain length. Our results provide a simple route for controlling the reversible thermochromism of PDA-based materials, allowing their utilization in a wider range of applications. PMID:23058980

  8. Suppression of superoxide anion generation catalyzed by xanthine oxidase with alkyl caffeates and the scavenging activity.

    Science.gov (United States)

    Masuoka, Noriyoshi; Kubo, Isao

    2016-05-01

    Alkyl caffeates are strong antioxidants and inhibitors of xanthine oxidase. However, it is unclear about the effect of caffeic acid and alkyl caffeates on superoxide anion (O2(-)) generation catalyzed by xanthine oxidase. Effects of caffeic acid and alkyl caffeates on the uric acid formation and O2(-) generation catalyzed by xanthine oxidase were analyzed. The scavenging activities of 1,1-diphenyl-2-picryhydrazyl (DPPH) radical and O2(-) generated with phenazine methosulfate (PMS) and NADH were examined. Caffeic acid derivatives equally suppressed O2(-) generation, and the suppression is stronger than inhibition of xanthine oxidase. Scavenging activity of O2(-) is low compared to the suppression of O2(-) generation. Suppression of O2(-) generation catalyzed by xanthine oxidase with caffeic acid derivatives was not due to enzyme inhibition or O2(-) scavenging but due to the reduction of xanthine oxidase molecules. Alkyl caffeates are effective inhibitors of uric acid and O2(-) catalyzed by xanthine oxidase as well as antioxidants for edible oil. PMID:26940252

  9. Enzymes versus heavy metal promoters and lewis acid catalysts in the synthesis of alkyl glycosides

    Czech Academy of Sciences Publication Activity Database

    Wimmer, Zdeněk; Zarevúcka, Marie; Reitmayerová, Pavla

    Poitiers, 2003. s. 12. [International Symposium Green Chemistry . Uses and Applications of Renewable Raw Materials. 19.05.2003-22.05.2003, Poitiers] R&D Projects: GA ČR GA203/02/0166 Institutional research plan: CEZ:AV0Z4055905 Keywords : alkyl glycosides Subject RIV: CC - Organic Chemistry

  10. Masked N-Heterocyclic Carbene-Catalyzed Alkylation of Phenols with Organic Carbonates.

    Science.gov (United States)

    Lui, Matthew Y; Yuen, Alexander K L; Masters, Anthony F; Maschmeyer, Thomas

    2016-09-01

    An easily prepared masked N-heterocyclic carbene, 1,3-dimethylimidazolium-2-carboxylate (DMI-CO2 ), was investigated as a "green" and inexpensive organocatalyst for the alkylation of phenols. The process made use of various low-toxicity and renewable alkylating agents, such as dimethyl- and diethyl carbonate, in a focused microwave reactor. DMI-CO2 was found to be a very active catalyst and excellent yields of a range of aryl alkyl ethers were obtained under relatively benign conditions. The observed difference in the conversion behavior of phenol methylation, in the presence of either the carbene or 1,8-diazabicycloundec-7-ene (DBU) catalyst, was rationalized on the basis of mechanistic investigations. The primary mode of action for the N-heterocyclic carbene is nucleophilic catalysis. Activation of the dialkyl carbonate electrophile results in concomitant evolution of an organo-soluble alkoxide, which deprotonates the phenolic starting material. In contrast, DBU is initially protonated by the phenol and thus consumed. Subsequent regeneration and participation in nucleophilic catalysis only becomes significant after some phenolate alkylation occurs. PMID:27528488

  11. Catalyst-controlled switch of regioselectivity in the asymmetric allylic alkylation of oxazolones with MBHCs.

    Science.gov (United States)

    Zhu, Gongming; Yang, Junxian; Bao, Guangjun; Zhang, Ming; Li, Jing; Li, Yiping; Sun, Wangsheng; Hong, Liang; Wang, Rui

    2016-06-14

    A catalyst-controlled switch of regioselectivity in asymmetric allylic alkylation of oxazolones with MBHCs was described. The SN2'-SN2' reaction catalysed by a quinine-derived base produced γ-selective secondary allylic oxazolone derivatives, whereas the addition-elimination reaction catalysed by an amino acid-derived bifunctional urea catalyst provided β-selective primary adducts. PMID:27250517

  12. IONIC LIQUIDS AS A CLEAN CATALYST FOR THE ALKYLATION OF ISOBUTANE WITH 2-BUTENE

    Science.gov (United States)

    Ionic liquids as a clean catalyst for the alkylation of isobutane with 2-buteneKyesang Yoo, a Vasudevan V. Namboodiri,b Panagiotis G. Smirniotis,*a and Rajender S. Varma*b a Department of Chemical Engineering, University of Cincinnati, Cincinnati, OH 45221-0171, USA. ...

  13. New Condensation Reaction of β-keto-δ-valerolactones, Carbon Disulfide and Alkyl Halides

    Institute of Scientific and Technical Information of China (English)

    You Ming WANG; Yu Xin LI; Su Hua WANG; Zheng Ming LI

    2004-01-01

    β-Keto-δ-valerolactones, which were obtained by reaction of acetoacetate with aldehydes or ketones, reacted with carbon disulfide, alkyl halides and a new condensation reaction was developed. The structures of the products 3 were confirmed by 1HNMR spectra and elemental analysis.

  14. Helsingør Statement on poly- and perfluorinated alkyl substances (PFASs)

    DEFF Research Database (Denmark)

    Scheringer, Martin; Trier, Xenia; Cousins, Ian T.; de Voogt, Pim; Fletcher, Tony; Wang, Zhanyun; Webster, Thomas F.

    2014-01-01

    In this discussion paper, the transition from long-chain poly- and perfluorinated alkyl substances (PFASs) to fluorinated alternatives is addressed. Long-chain PFASs include perfluoroalkyl carboxylic acids (PFCAs) with 7 or more perfluorinated carbons, perfluoroalkyl sulfonic acids (PFSAs) with 6...

  15. Kinematic viscosity of biodiesel components (fatty acid alkyl esters) and related compounds at low temperatures

    Science.gov (United States)

    Biodiesel, defined as the mono-alkyl esters of vegetable oils and animal fats, has undergone rapid development and acceptance recently. Kinematic viscosity is one of the fuel properties specified in biodiesel standards, with 40 deg C being the temperature at which this property is to be determined ...

  16. Immunological detection and quantification of DNA components structurally modified by alkylating carcinogens, mutagens and chemotherapeutic agents

    International Nuclear Information System (INIS)

    The detection and quantification of defined reaction products of chemical mutagens and carcinogens (and of many cancer chemotherapeutic agents) with DNA require highly sensitive analytical techniques. The exceptional capability of immunoglobulins to recognize subtle alterations of molecular structure (especially when monoclonal antibodies are used to maximize specificity), outstanding sensitivity of immunoanalysis by high-affinity antibodies, and the fact that radioactively-labelled agents are not required suggest the utility of a radioimmunoassay to recognize and quantitate alkylated DNA products. We have recently developed a set of high-affinity monoclonal antibodies (secreted by mouse x mouse as well as by rat x rat hybridomas; antibody affinity constants, 109 to > 1010 lmol) specifically directed against several DNA alkylation products with possible relevance in relation to both mutagenesis and malignant transformation of mammalian cells. These alkylation products include 06-N-butyldeoxyguanosine, and 04-ethyldeoxythymidine. When used in a radioimmunassay, an antibody specific for 06-ethyldeoxyguanosine, for example, will detect this product at an 06-ethyldeoxyguanosine/deoxyguanosine molar ratio of approx. 3 x 10-7 in a hydrolysate of 100 ug of DNA. The limit of detection can be lowered further if the respective alkyldeoxynucleosides are separated by HPLC from the DNA hydrolysate prior to the RIA. The anti-alkyldeoxynucleoside monoclonal antibodies can also be used to visualize, by immunostaining and fluorescence microscopy combined with electronic image intensification, specific alkylation products in the nuclear DNA of individual cells, and to localize structurally modified bases in double-stranded DNA molecules by transmission electron microscopy

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

    OpenAIRE

    carboxylic, Ionic liquids as solvent for efficient e

    2010-01-01

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

  18. Characterization of alkyl carbon in forest soils by CPMAS 13C NMR spectroscopy and dipolar dephasing

    Science.gov (United States)

    Kogel-Knabner, I.; Hatcher, P.G.

    1989-01-01

    Samples obtained from forest soils at different stages of decomposition were treated sequentially with chloroform/methanol (extraction of lipids), sulfuric acid (hydrolysis), and sodium chlorite (delignification) to enrich them in refractory alkyl carbon. As revealed by NMR spectroscopy, this treatment yielded residues with high contents of alkyl carbon. In the NMR spectra of residues obtained from litter samples, resonances for carbohydrates are also present, indicating that these carbohydrates are tightly bound to the alkyl carbon structures. During decomposition in the soils this resistant carbohydrate fraction is lost almost completely. In the litter samples the alkyl carbon shows a dipolar dephasing behavior indicative of two structural components, a rigid and a more mobile component. As depth and decomposition increase, only the rigid component is observed. This fact could be due to selective degradation of the mobile component or to changes in molecular mobility during decomposition, e.g., because of an increase in cross linking or contact with the mineral matter of the soil.

  19. The Cyclization of Alkyl Side Chains of Naphthalenes: GC/Potential Energies/FTIR Approach

    Czech Academy of Sciences Publication Activity Database

    Straka, Pavel; Novotná, M.; Buryan, P.; Bičáková, Olga

    2014-01-01

    Roč. 5, č. 14 (2014), s. 957-968. ISSN 2156-8251 Institutional support: RVO:67985891 Keywords : alkyl naphtalenes * retention times * molecular mechanics * Van der Waals forces Subject RIV: CC - Organic Chemistry http://www.scirp.org/journal/AJAC/

  20. Repair of Alkylation Damage in Eukaryotic Chromatin Depends on Searching Ability of Alkyladenine DNA Glycosylase.

    Science.gov (United States)

    Zhang, Yaru; O'Brien, Patrick J

    2015-11-20

    Human alkyladenine DNA glycosylase (AAG) initiates the base excision repair pathway by excising alkylated and deaminated purine lesions. In vitro biochemical experiments demonstrate that AAG uses facilitated diffusion to efficiently search DNA to find rare sites of damage and suggest that electrostatic interactions are critical to the searching process. However, it remains an open question whether DNA searching limits the rate of DNA repair in vivo. We constructed AAG mutants with altered searching ability and measured their ability to protect yeast from alkylation damage in order to address this question. Each of the conserved arginine and lysine residues that are near the DNA binding interface were mutated, and the functional impacts were evaluated using kinetic and thermodynamic analysis. These mutations do not perturb catalysis of N-glycosidic bond cleavage, but they decrease the ability to capture rare lesion sites. Nonspecific and specific DNA binding properties are closely correlated, suggesting that the electrostatic interactions observed in the specific recognition complex are similarly important for DNA searching complexes. The ability of the mutant proteins to complement repair-deficient yeast cells is positively correlated with the ability of the proteins to search DNA in vitro, suggesting that cellular resistance to DNA alkylation is governed by the ability to find and efficiently capture cytotoxic lesions. It appears that chromosomal access is not restricted and toxic sites of alkylation damage are readily accessible to a searching protein. PMID:26317160

  1. Exploring a chemical encoding strategy for combinatorial synthesis using Friedel-Crafts alkylation

    OpenAIRE

    Scott, Robin H.; Barnes, Colin; Gerhard, Ulrich; Balasubramanian, Shankar

    1999-01-01

    The use of scandium(III) triflate and ytterbium(III) triflate-catalysed Friedel-Crafts alkylation to insert a set of hydroxymethyl pyrrole amide tags (1b-i) on to polystyrene resins under mild conditions and the encoding of a split and mix peptide library is demonstrated.

  2. The effect of MFI zeolite lamellar and related mesostructures on toluene disproportionation and alkylation

    Czech Academy of Sciences Publication Activity Database

    Jo, Ch.; Ryoo, R.; Žilková, Naděžda; Vitvarová, Dana; Čejka, Jiří

    2013-01-01

    Roč. 3, č. 8 (2013), s. 2119-2129. ISSN 2044-4753 R&D Projects: GA ČR(CZ) GAP106/12/0189 Institutional support: RVO:61388955 Keywords : Adsorption measurement * Alkylation of toluene * Isopropyl alcohol s Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 4.760, year: 2013

  3. Memory effects in palladium-catalyzed allylic Alkylations of 2-cyclohexen-1-yl acetate

    DEFF Research Database (Denmark)

    Svensen, Nina; Fristrup, Peter; Tanner, David Ackland;

    2007-01-01

    The objective of this work was to characterize the enantiospecificity of the allylic alkylation of enantioenriched 2-cyclohexen-1-yl acetate with the enolate ion of dimethyl malonate catalyzed by unsymmetrical palladium catalysts. The precatalysts employed were (eta(3)-allyl)PdLCl, where L is a...

  4. Direct C-H alkylation and indole formation of anilines with diazo compounds under rhodium catalysis.

    Science.gov (United States)

    Mishra, Neeraj Kumar; Choi, Miji; Jo, Hyeim; Oh, Yongguk; Sharma, Satyasheel; Han, Sang Hoon; Jeong, Taejoo; Han, Sangil; Lee, Seok-Yong; Kim, In Su

    2015-12-18

    The rhodium(III)-catalyzed direct functionalization of aniline C-H bonds with α-diazo compounds is described. These transformations provide a facile construction of ortho-alkylated anilines with diazo malonates or highly substituted indoles with diazo acetoacetates. PMID:26458276

  5. Adsorption Kinetics of Alkyl Polyglucoside at the Air-Solution Interface

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The air-solution equilibrium tension ye and dynamic surface tension ye, of nonionic surfactant alkyl polyglucoside have been studied. ye was measured by the Wilhelmy method with tension vs. concentration curve. The ye decays were measured in the range 0.2~20 s using a maximum bubble pressure instrument and analyzed with the Ward and Tordai cquation.

  6. Influence of Backbone Fluorination in Regioregular Poly(3-alkyl-4-fluoro)thiophenes

    KAUST Repository

    Fei, Zhuping

    2015-06-03

    © 2015 American Chemical Society. We report two strategies toward the synthesis of 3-alkyl-4-fluorothiophenes containing straight (hexyl and octyl) and branched (2-ethylhexyl) alkyl groups. We demonstrate that treatment of the dibrominated monomer with 1 equiv of alkyl Grignard reagent leads to the formation of a single regioisomer as a result of the pronounced directing effect of the fluorine group. Polymerization of the resulting species affords highly regioregular poly(3-alkyl-4-fluoro)thiophenes. Comparison of their properties to those of the analogous non-fluorinated polymers shows that backbone fluorination leads to an increase in the polymer ionization potential without a significant change in optical band gap. Fluorination also results in an enhanced tendency to aggregate in solution, which is ascribed to a more co-planar backbone on the basis of Raman and DFT calculations. Average charge carrier mobilities in field-effect transistors are found to increase by up to a factor of 5 for the fluorinated polymers.

  7. Root uptake and translocation of perfluorinated alkyl acids by three hydroponically grown crops

    NARCIS (Netherlands)

    S. Felizeter; M.S. McLachlan; P. de Voogt

    2014-01-01

    Tomato, cabbage, and zucchini plants were grown hydroponically in a greenhouse. They were exposed to 14 perfluorinated alkyl acids (PFAAs) at four different concentrations via the nutrient solution. At maturity the plants were harvested, and the roots, stems, leaves, twigs (where applicable), and ed

  8. Carbon Dioxide Induced Alkene Extrusion from Bis(pentamethylcyclopentadienyl)titanium(III) Alkyls

    NARCIS (Netherlands)

    Luinstra, Gerrit A.; Teuben, Jan H.

    1987-01-01

    Reaction of titanium(III) alkyls, (η5-C5Me5)2TiR (R = Et or Prn), in toluene solution with CO2 proceeds at room temperature with formation of the titanium formate (η5-C5Me5)2TiO2CH, and the corresponding alkene (ethene or propene).

  9. Polyvinylchloride/clay nanocomposites based on the alkyl-amine intercalates with different length of chain

    Czech Academy of Sciences Publication Activity Database

    Kalendová, A.; Pospíšil, M.; Kovářová, L.; Měřínská, D.; Šimoník, J.; Čapková, P.; Valášková, M.; Vlková, Helena

    Akron : Polymer Processing Society , 2004. s. 248. [Polymer Processing Society Annual Meeting. 20.06.2004-24.06.2004, Akron] R&D Projects: GA AV ČR KSK4050111 Keywords : polyvinylchloride/clay * alkyl-amine intercalates * polymer nanotechnology Subject RIV: CD - Macromolecular Chemistry

  10. A cyclic (alkyl)(amido)carbene: synthesis, study and utility as a desulfurization reagent.

    Science.gov (United States)

    McCarty, Zachary R; Lastovickova, Dominika N; Bielawski, Christopher W

    2016-04-01

    The synthesis and study of a cyclic (alkyl)(amido)carbene is described. The carbene was found to undergo C-H insertion at low temperatures, formed cyclopropenes upon exposure to alkynes, and facilitated desulfurization reactions. Spectroscopic studies revealed that the carbene is strongly π-accepting but retains a complimentary degree of σ-donating properties. PMID:27010415

  11. Enantioselective copper catalyzed allylic alkylation using Grignard reagents; Applications in synthesis

    NARCIS (Netherlands)

    Zijl, Anthoni Wouter van

    2009-01-01

    Enantioselective copper catalyzed allylic alkylation is a powerful carbon-carbon bond forming reaction. In this thesis the development of a new catalyst for the use of Grignard reagents in this reaction is described. This catalyst is based on copper and the ligand Taniaphos. The high regio- and enan

  12. Side reactions of N-terminal cysteine residue in peptides alkylated with various reagents

    Czech Academy of Sciences Publication Activity Database

    Řehulková, Helena; Řehulka, Pavel

    Jena : ESF, 2008. s. 26. [Central and Eastern European Proteomic Conference /2./. 12.10.2008-15.10.2008, Jena] R&D Projects: GA MŠk 1M06030 Institutional research plan: CEZ:AV0Z40310501 Keywords : alkylation of proteins/peptides * MALDI-MS/MS Subject RIV: CB - Analytical Chemistry, Separation

  13. Formation of furan fatty alkyl esters from their bis-epoxide fatty esters

    Science.gov (United States)

    Reactions of epoxidized alkyl soyate with four different alcohols: ethanol, isopropyl alcohol, 2-ethylhexanol, benzyl alcohol, in the presence of Bronsted acid catalyst, were investigated. Products that were not reported in prior studies of similar reactions were found. These were furan fatty acid a...

  14. Z-Selective copper-catalyzed asymmetric allylic alkylation with Grignard reagents.

    Science.gov (United States)

    Giannerini, Massimo; Fañanás-Mastral, Martín; Feringa, Ben L

    2012-03-01

    Allylic gem-dichlorides undergo regio- and enanantioselective (er up to 99:1) copper-catalyzed allylic alkylation with Grignard reagents affording chiral Z-vinyl chlorides. This highly versatile class of synthons can be subjected to Suzuki cross coupling affording optically active Z-alkenes and 1,3-cis,trans dienes. PMID:22352853

  15. Stereospecific Ni-Catalyzed Cross-Coupling of Potassium Alkenyltrifluoroborates with Alkyl Halides

    OpenAIRE

    Molander, Gary A.; Argintaru, O. Andreea

    2014-01-01

    A general method for the alkenylation of alkyl electrophiles using nearly stoichiometric amounts of the air- and moisture-stable potassium organotrifluoroborates has been developed. Various functional groups were tolerated on both the nucleophilic and electrophilic partner. Reactions of highly substituted E- and Z-alkenyltrifluoroborates, as well as vinyl- and propenyltrifluoroborates, were successful, and no loss of stereochemistry or regiochemistry was observed.

  16. Z-Selective Copper-Catalyzed Asymmetric Allylic Alkylation with Grignard Reagents

    OpenAIRE

    Giannerini, Massimo; Fananas-Mastral, Martin; Feringa, Ben L.; Fañanás-Mastral, Martín

    2012-01-01

    Allylic gem-dichlorides undergo regio- and enanantioselective (er up to 99:1) copper-catalyzed allylic alkylation with Grignard reagents affording chiral Z-vinyl chlorides. This highly versatile class of synthons can be subjected to Suzuki cross coupling affording optically active Z-alkenes and 1,3-cis,trans dienes.

  17. Theoretical study of aromaticity in inorganic tetramer clusters

    Indian Academy of Sciences (India)

    Sandeep Nigam; Chiranjib Majumder; S K Kulshreshtha

    2006-11-01

    Ground state geometry and electronic structure of M$^{2-}_{4}$ cluster (M = B, Al, Ga) have been investigated to evaluate their aromatic properties. The calculations are performed by employing the Density Functional Theory (DFT) method. It is found that all these three clusters adopt square planar configuration. Results reveal that square planar M$^{2-}_{4}$ dianion exhibits characteristics of multifold aromaticity with two delocalised -electrons. In spite of the unstable nature of these dianionic clusters in the gas phase, their interaction with the sodium atoms forms very stable dipyramidal M4Na2 complexes while maintaining their square planar structure and aromaticity.

  18. Temporal variability, sources, and sinks of C1-C5 alkyl nitrates in Coastal New England

    Directory of Open Access Journals (Sweden)

    B. C. Sive

    2009-11-01

    Full Text Available Seven C1-C5 alkyl nitrates were measured both on the mainland and off the coast of New Hampshire using gas chromatographic techniques. Five separate data sets will be presented to characterize the seasonal and diurnal trends and the major sources and loss processes of these compounds. In situ measurements were conducted at the University of New Hampshire (UNH Atmospheric Observing Station at Thompson Farm (TF located in southeast NH during winter (January–February and summer (June–August 2002 and summer (July–August 2004. The median (±standard deviation total alkyl nitrate mixing ratio (ΣRONO2 was 25 (±7 in winter and 16 (±14 pptv in summer. Furthermore, daily canister samples collected at midday and later analyzed in the laboratory from January 2004–February 2008 gave median ΣRONO2 of 23 (±8 in winter and 14 (±10 pptv in summer. Alkyl nitrate mixing ratios increased throughout the morning and were highest in the afternoon reflecting mixing of remnant boundary layer air toward the surface and photochemical production during the day. During summers 2002 and 2004, MeONO2 decreased overnight and reached minimum hourly average mixing ratios in the early morning (05:00–07:00 LT. Comparison with wind speed and trace gas (i.e., hydrocarbons, ozone, carbon monoxide, total reactive nitrogen trends suggested that dry deposition contributed to the early morning MeONO2 minimum which is a previously unaccounted for removal mechanism. The mean dry deposition rate and velocity of MeONO2 was estimated to be −0.5 nmol m−2 hr−1 and 0.13 cm s−1, respectively. Results from ambient air and surface seawater measurements made onboard the NOAA R/V Ronald H. Brown in the Gulf of Maine during the 2002 New England Air Quality Study and from ambient canister samples collected throughout the Great Bay estuary in August 2003 are also presented. Comparisons between the alkyl nitrate trends with anthropogenic and marine source fingerprints and tracers

  19. Thermodynamic Interactions between Polystyrene and Long-Chain Poly(n-Alkyl Acrylates) Derived from Plant Oils.

    Science.gov (United States)

    Wang, Shu; Robertson, Megan L

    2015-06-10

    Vegetable oils and their fatty acids are promising sources for the derivation of polymers. Long-chain poly(n-alkyl acrylates) and poly(n-alkyl methacrylates) are readily derived from fatty acids through conversion of the carboxylic acid end-group to an acrylate or methacrylate group. The resulting polymers contain long alkyl side-chains with around 10-22 carbon atoms. Regardless of the monomer source, the presence of alkyl side-chains in poly(n-alkyl acrylates) and poly(n-alkyl methacrylates) provides a convenient mechanism for tuning their physical properties. The development of structured multicomponent materials, including block copolymers and blends, containing poly(n-alkyl acrylates) and poly(n-alkyl methacrylates) requires knowledge of the thermodynamic interactions governing their self-assembly, typically described by the Flory-Huggins interaction parameter χ. We have investigated the χ parameter between polystyrene and long-chain poly(n-alkyl acrylate) homopolymers and copolymers: specifically we have included poly(stearyl acrylate), poly(lauryl acrylate), and their random copolymers. Lauryl and stearyl acrylate were chosen as model alkyl acrylates derived from vegetable oils and have alkyl side-chain lengths of 12 and 18 carbon atoms, respectively. Polystyrene is included in this study as a model petroleum-sourced polymer, which has wide applicability in commercially relevant multicomponent polymeric materials. Two independent methods were employed to measure the χ parameter: cloud point measurements on binary blends and characterization of the order-disorder transition of triblock copolymers, which were in relatively good agreement with one another. The χ parameter was found to be independent of the alkyl side-chain length (n) for large values of n (i.e., n > 10). This behavior is in stark contrast to the n-dependence of the χ parameter predicted from solubility parameter theory. Our study complements prior work investigating the interactions between

  20. Response to alkylation damage of fibroblast cells from patients with therapy-related myeloid neoplasms

    International Nuclear Information System (INIS)

    Therapy-related myeloid neoplasms (t-MNs) are severe long-term consequences of chemo- and/or radiotherapy for a primary disease. It is generally accepted that genetic predisposition plays a major role in therapy-related leukemogenesis. The hypothesis that cellular response mechanisms to alkylation damage are deregulated in constitutional cells of patients with t-MNs due to predisposing genetic events was tested in this study. It was further examined whether genetic instability would also be a consequence of such a treatment. Therefore primary fibroblast cultures were established from skin biopsies from patients with t-MNs and matched healthy controls. These cultures were treated with the cyclophosphamide derivate phosphoramide mustard (PM), a bifunctional alkylating agent. The cellular response to alkylation damage was assessed with respect to cell viability, cell cycle regulation and chromosomal stability. Increased sensitivity to PM treatment could be demonstrated in 7/13 (54%) patient samples. IC50, IC75 and IC90 values as well as the percentage of viable cells at higher PM concentrations were significantly different when comparing patient and control groups. Both, fibroblast cells from patients and controls, properly induced cell cycle arrest following alkylating injury in the G2/M phase of the cell cycle. Gross genomic alterations like chromosome and chromatid breaks as well as structural and clonal numerical aberrations could be induced via PM treatment. The extent of induced changes per mitosis, however, was comparable in both, patient and control fibroblast cultures. These data demonstrate for the first time hypersensitivity of constitutional cells from patients with t-MNs to alkylation treatment indicating impaired DNA damage response and/or repair mechanisms. (author)

  1. Application of aromatization catalyst in synthesis of carbon nanotubes

    Indian Academy of Sciences (India)

    Song Rongjun; Yang Yunpeng; Ji Qing; Li Bin

    2012-02-01

    In a typical chemical vapour deposition (CVD) process for synthesizing carbon nanotubes (CNTs), it was found that the aromatization catalysts could promote effectively the formation of CNT. The essence of this phenomenon was attributed to the fact that the aromatization catalyst can accelerate the dehydrogenation–cyclization and condensation reaction of carbon source, which belongs to a necessary step in the formation of CNTs. In this work, aromatization catalysts, H-beta zeolite, HZSM-5 zeolite and organically modified montmorillonite (OMMT) were chosen to investigate their effects on the formation of multi-walled carbon nanotubes (MWCNTs) via pyrolysis method when polypropylene and 1-hexene as carbon source and Ni2O3 as the charring catalyst. The results demonstrated that the combination of those aromatization catalysts with nickel catalyst can effectively improve the formation of MWCNTs.

  2. Affinity labelling enzymes with esters of aromatic sulfonic acids

    Science.gov (United States)

    Wong, Show-Chu; Shaw, Elliott

    1977-01-01

    Novel esters of aromatic sulfonic acids are disclosed. The specific esters are nitrophenyl p- and m-amidinophenylmethanesulfonate. Also disclosed is a method for specific inactivation of the enzyme, thrombin, employing nitrophenyl p-amidinophenylmethanesulfonate.

  3. Six-Membered Aromatic Polyazides: Synthesis and Application

    Directory of Open Access Journals (Sweden)

    Sergei V. Chapyshev

    2015-10-01

    Full Text Available Aromatic polyazides are widely used as starting materials in organic synthesis and photochemical studies, as well as photoresists in microelectronics and as cross-linking agents in polymer chemistry. Some aromatic polyazides possess high antitumor activity, while many others are of considerable interest as high-energy materials and precursors of high-spin nitrenes and C3N4 carbon nitride nanomaterials. The use of aromatic polyazides in click-reactions may be a new promising direction in the design of various supramolecular systems possessing interesting chemical, physical and biological properties. This review is devoted to the synthesis, properties and applications of six-membered aromatic compounds containing three and more azido groups in the ring.

  4. THE UPTAKE OF AROMATIC AND BRANCHED CHAIN HYDROCARBONS BY YEAST

    Science.gov (United States)

    Studies of the hydrocarbon utilizing yeasts, Candida maltosa and C. lipolytica, have shown that both were capable of reducing recoverable amounts of branched chain and aromatic hydrocarbons in a mixture of naphthalene, tetradecane, hexadecane, pristane (tetra-methylpentadecane). ...

  5. Aromatic Plants as a Source of Bioactive Compounds

    Directory of Open Access Journals (Sweden)

    Panagiota Florou-Paneri

    2012-09-01

    Full Text Available Aromatic plants, also known as herbs and spices, have been used since antiquity as folk medicine and as preservatives in foods. The best known aromatic plants, such as oregano, rosemary, sage, anise, basil, etc., originate from the Mediterranean area. They contain many biologically active compounds, mainly polyphenolics, which have been found to possess antimicrobial, antioxidant, antiparasitic, antiprotozoal, antifungal, and anti-inflammatory properties. Currently, the demand for these plants and their derivatives has increased because they are natural, eco-friendly and generally recognized as safe products. Therefore, aromatic plants and their extracts have the potential to become new generation substances for human and animal nutrition and health. The purpose of this review is to provide an overview of the literature surrounding the in vivo and in vitro use of aromatic plants.

  6. Provisional Guidance for Quantitative Risk Assessment of Polycyclic Aromatic Hydrocarbons

    Science.gov (United States)

    Polycyclic Aromatic Hydrocarbons (PAHs) are products of incomplete combustion of organic materials; sources are, thus, widespread,including cigarette smoke, municipal waste incineration, wood stove emissions, coal conversion, energy production form fossil fuels, and automobile an...

  7. Synthesis of alkyl-ether glycerophospholipids in rat glomerular mesangial cells: evidence for alkyldihydroxyacetone phosphate synthase activity

    International Nuclear Information System (INIS)

    We studied the ability of rat glomerular mesangial cells and their microsomal fractions to incorporate 1-[14C]hexadecanol to glycerophospholipids via an O-alkyl ether linkage and assessed the presence and activity of the required enzyme: alkyl-dihydroxy acetone phosphate synthase. Suspensions of cultured mesangial cells incorporated 1-[14C]hexadecanol to the phosphatidyl ethanolamine and phosphatidyl choline lipid pools, via a bond resistant to acid and base hydrolysis. When cell homogenates or microsomal fractions were incubated with palmitoyl-DHAP and 1-[14C]hexadecanol, alkyl-DHAP and 1-O-alkyl glycerol were formed (alkyl:hexadecyl). The activity of the enzyme responsible for the O-alkyl product formation was calculated to be 2.5 +/- 0.3 and 544 +/- 50 pmoles/min/mg protein for mesangial cell homogenates and mesangial cell microsomes, respectively. These observations provide evidence that mesangial cells may elaborate either linked lipid precursors de novo for the biosynthesis of O-alkyl glycerophospholipids

  8. Synthesis and characterization of organosoluble aromatic copolyimids

    Institute of Scientific and Technical Information of China (English)

    YANG Jintian; HUANG Wei; ZHOU Yongfeng; YAN Deyue

    2007-01-01

    A series of aromatic copolyimides was success fully synthesized from the commercial pyromellitic dianhy dride (PMDA) with a commercial diamine p-phenyldiamine (PDA) and a diamine 4,4'-methylenebis-(2-tert-butylaniline)(MBTBA) specially designed by the authors.The copoly imides were characterized by Infra-red (IR),Nuclear Magnetic Resonance (NMR),Gel Permeation Chromato graphy (GPC),Ultraviolet Visual (UV-Vis),Thermogra vimetic Analysis (TGA) and Dynamic Mechanical Analysis (DMA).The copolyimide was precipitated in m-cresol in the polymerization process when the molar ratio of MBTBA and PDA was lower than 6/4.The number-average molecular weight of the soluble copolyimides measured by GPC was larger than 4.0 x 104,and the polydispersity index was higher than 1.5.Only one glass transition temperature of these copolyimdies was detected around 360℃ by DMA.The copolyimides did not show appreciable decomposition up to 500℃ under N2,and the thermal stability of the copolyimide increased a little with the introduction of PDA into the polyimide main chain.

  9. Porphyrins Fused with Unactivated Polycyclic Aromatic Hydrocarbons

    KAUST Repository

    Diev, Vyacheslav V.

    2012-01-06

    A systematic study of the preparation of porphyrins with extended conjugation by meso,β-fusion with polycyclic aromatic hydrocarbons (PAHs) is reported. The meso-positions of 5,15-unsubstituted porphyrins were readily functionalized with PAHs. Ring fusion using standard Scholl reaction conditions (FeCl 3, dichloromethane) occurs for perylene-substituted porphyrins to give a porphyrin β,meso annulated with perylene rings (0.7:1 ratio of syn and anti isomers). The naphthalene, pyrene, and coronene derivatives do not react under Scholl conditions but are fused using thermal cyclodehydrogenation at high temperatures, giving mixtures of syn and anti isomers of the meso,β-fused porphyrins. For pyrenyl-substituted porphyrins, a thermal method gives synthetically acceptable yields (>30%). Absorption spectra of the fused porphyrins undergo a progressive bathochromic shift in a series of naphthyl (λ max = 730 nm), coronenyl (λ max = 780 nm), pyrenyl (λ max = 815 nm), and perylenyl (λ max = 900 nm) annulated porphyrins. Despite being conjugated with unsubstituted fused PAHs, the β,meso-fused porphyrins are more soluble and processable than the parent nonfused precursors. Pyrenyl-fused porphyrins exhibit strong fluorescence in the near-infrared (NIR) spectral region, with a progressive improvement in luminescent efficiency (up to 13% with λ max = 829 nm) with increasing degree of fusion. Fused pyrenyl-porphyrins have been used as broadband absorption donor materials in photovoltaic cells, leading to devices that show comparatively high photovoltaic efficiencies. © 2011 American Chemical Society.

  10. [Polycyclic aromatic hydrocarbons exposure and birth defects].

    Science.gov (United States)

    Lin, S S; Huang, Y; Wang, C Y; Ren, A G

    2016-06-01

    Birth defects are one of the most common adverse birth outcomes, which create a heavy economic burden to the country, society and family. And they are also one of the biggest problems facing public health today. Polycyclic aromatic hydrocarbons (PAHs) are a group of toxic pollutants existing in the environment widely, resulting from incomplete organic matter combustion, and can be taken into the body through various ways including the digestive tract, respiratory tract and so on. Recent researches suggest that the exposure of PAHs may be associated with various birth defects, while the special mechanism isn't very clear. This paper is a review of the relationship between PAHs and birth defects from the aspects of epidemiological data, experimental evidence on animals, which indicates that exposure of PAHs during pregnancy may be associated with birth defects including congenital heart defects, neural tube defects and cleft lip/plate. Furthermore, we explored the possible mechanism, including oxidative stress, oxidative damage and the changes of signal transduction pathway in order to provide some recommendations and suggestions on the future work. PMID:27256742

  11. Optimization of low ring polycylic aromatic biodegradation

    Science.gov (United States)

    Othman, N.; Abdul-Talib, S.; Tay, C. C.

    2016-07-01

    Polycyclic aromatic hydrocarbons (PAHs) are recalcitrance and persistence that finally turn into problematic environmental contaminants. Microbial degradation is considered to be the primary mechanism of PAHs removal from the environment due to its organic criteria. This study is carried out to optimize degradation process of low ring PAHs. Bacteria used in this study was isolated from sludge collected from Kolej Mawar, Universiti Teknologi MARA, Shah Alam, Selangor. Working condition namely, substrate concentration, bacteria concentration, pH and temperature were optimized. PAHs in the liquid sample was extracted by using solid phase microextractio equipped with a 7 µm polydimethylsiloxane (PDMS) SPME fibr. Removal of PAHs were assessed by measuring PAHs concentration using GC-FID. Results from the optimization study of biodegradation indicated that maximum rate of PAHs removal occurred at 100 mgL-1 of PAHs, 10% bacteria concentration, pH 7.0 and 30°C. These working condition had proved the effectiveness of using bacteria in biodegradation process of PAHs.

  12. Polycyclic aromatic hydrocarbon molecules in astrophysics

    Science.gov (United States)

    Rastogi, Shantanu; Pathak, Amit; Maurya, Anju

    2013-06-01

    Polycyclic aromatic hydrocarbon (PAH) molecules are responsible for the mid-infrared emission features. Their ubiquitous presence in almost all types of astrophysical environments and related variations in their spectral profilesmake them an important tool to understand the physics and chemistry of the interstellar medium. The observed spectrum is generally a composite superposition of all different types of PAHs possible in the region. In the era of space telescopes the spectral richness of the emission features has enhanced their importance as probe and also the need to understand the variations with respect to PAH size, type and ionic state. Quantum computational studies of PAHs have proved useful in elucidating the profile variations and put constraints on the possible types of PAHs in different environments. The study of PAHs has also significantly contributed to the problems of diffuse interstellar bands (DIBs), UV extinction and understanding the chemistry of the formation of complex organics in space. The review highlights the results of various computational models for the understanding of infrared emission features, the PAH-DIB relation, formation of prebiotics and possible impact in the understanding of far-infrared features.

  13. Saudi decree encourages MTBE, Chevron aromatics plant

    International Nuclear Information System (INIS)

    Chevron Chemical (Houston), encouraged by a new Saudi royal decree that establishes extremely low feedstock prices, is in final negotiations to build a novel aromatics plant in Saudi Arabia. Chevron says it plans to close the deal and announce details the first week of March. The unit will be based on Chevron's Aromax reforming process, which uses a zeolite catalyst to convert light naphtha into benzene and toluene. No existing plant is using the technology, but Chevron is building a $250-million, 150-million gal/year Aromax unit at its refinery site in Pascagoula, MS, and Idemitsu has licensed the process for a plant in Chiba, Japan. The Saudi decree, issued late last year, pegs domestic feedstocks - propane, butane, and naphthas - at 30% below the lowest price of the prior quarter in major non-domestic markets. That clarifies and guarantees the Saudi feedstock price, which has always been nebulous, and thus allows project feasibility to be more clearly assessed. The decree is designed to encourage further private petrochemical investment in the country. In particular, the Saudi government hopes guaranteed low prices for butane will encourage more methyl tert-butyl ether (MTBE) projects. Arabian American Chemical, a 50/50 joint venture between Mobile and Arabian Chemical Investments, said in October of last year that its 830,000-m.t./year MTBE project at Yanbu, Saudi Arabia, would go ahead if feedstock questions could be resolved. The decree apparently resolves those questions

  14. Aromatizing unzipping polyester for EUV photoresist

    Science.gov (United States)

    Matsuzawa, Kensuke; Mesch, Ryan; Olah, Mike; Wang, Wade; Phillips, Scott T.; Willson, C. Grant

    2015-03-01

    New "self-immolating" or "unzipping" polymers, materials that depolymerize in response to irradiation, were designed and prepared successfully. We studied several candidate polymers and ultimately chose two of them for further development. One is a polyester that aromatizes upon depolymerization. The unzipping reaction initiated by UV exposure in solution was confirmed. The polymer was then studied in thin films to assess its potential for use in formulating photoresists. The neat polymer was tested as a blend with novolac resin. The effect of unzipping polyester loading in novolac on the rate of dissolution of films in TMAH was studied. Inhibition occurs at 20-30% loading. The films were exposed with DUV light and patterning was observed. The sensitivity of the unzipping polyester formulation is low in part due to the low absorption of the polymer for UV light. However, the polymer showed higher sensitivity with EUV exposure and first contrast curves show sensitivity in the range of 20-25mJ/cm2.

  15. Coassembly of aromatic dipeptides into biomolecular necklaces.

    Science.gov (United States)

    Yuran, Sivan; Razvag, Yair; Reches, Meital

    2012-11-27

    This paper describes the formation of complex peptide-based structures by the coassembly of two simple peptides, the diphenylalanine peptide and its tert-butyl dicarbonate (Boc) protected analogue. Each of these peptides can self-assemble into a distinct architecture: the diphenylalanine peptide into tubular structures and its analogue into spheres. Integrated together, these peptides coassemble into a construction of beaded strings, where spherical assemblies are connected by elongated elements. Electron and scanning force microscopy demonstrated the morphology of these structures, which we termed "biomolecular necklaces". Additional experiments indicated the reversibility of the coassembly process and the stability of the structures. Furthermore, we suggest a possible mechanism of formation for the biomolecular necklaces. Our suggestion is based on the necklace model for polyelectrolyte chains, which proposes that a necklace structure appears as a result of counterion condensation on the backbone of a polyelectrolyte. Overall, the approach of coassembly, demonstrated using aromatic peptides, can be adapted to any peptides and may lead to the development and discovery of new self-assembled architectures formed by peptides and other biomolecules. PMID:23061818

  16. Stability of polycyclic aromatic compounds in polyurethane foam-type passive air samplers upon O3 exposure

    Science.gov (United States)

    Jariyasopit, Narumol; Liu, Yongchun; Liggio, John; Harner, Tom

    2015-11-01

    Stability of polycyclic aromatic compounds (PACs) in polyurethane foam (PUF) disks upon O3 exposure was studied in a flow tube. A wide range of PACs was evaluated by spiking PUF disks with PACs and exposing to O3 at concentrations that were equivalent to two months exposure, a typical deployment period for these passive air samplers. Ambient concentrations of O3 (˜50 ppb) at 0% and 50% relative humidity (RH) were applied. At 0% RH, 23 of 68 PACs yielded more than 50% loss after exposure. The mean percent loss was 30% with perylene and 9,10-dimethylanthracene the most reactive polycyclic aromatic hydrocarbons (PAHs) and alkylated PAHs, respectively. At 50% RH, 77% of the studied PACs was stable upon O3 exposure (PACexposed/PACunexposed > 0.7). The mean percent loss was 17% and only 7 of 68 PACs yielded greater than 50% loss. In general, the reactivity of most of the PACs decreased at higher RH, except for the reactive PAHs (acenaphthylene, 2,3-dimethylanthracene, 9,10-dimethylanthracene, dibenzothiophene, and 2-methyldibenzothiophene) which demonstrated lower RH dependence. The experimental conditions in this study represent a worst case scenario for the stability of PACs sorbed to PUF. In reality, the sampling of PACs in ambient air represents an 'aged' component of PACs where the most reactive species have already partially been removed. Also, PACs in ambient air will be associated with the particle phase to varying extents that will help to enhance their stability. Therefore, under regular operating conditions, over a 2-month exposure, we expect a minimal error in the measurement of total concentration of PACs in air using the PUF disk passive sampler.

  17. Solubilities of solid polycyclic aromatic hydrocarbons and polycyclic aromatic heterocycles in pressurized hot water

    Czech Academy of Sciences Publication Activity Database

    Karásek, Pavel; Planeta, Josef; Roth, Michal

    Boulder, CO: National Institute of Standards and Technology, 325 Broadway, Boulder, CO 80305, USA, 2006 - (Friend, D.; Frenkel, M.; Muzny, C.; Hardin, G.). s. 641-642 [International Conference on Chemical Thermodynamics /19./. THERMO International 2006. 30.07.2006-04.08.2006, Boulder, CO] R&D Projects: GA AV ČR IAA4031301; GA AV ČR KJB400310504; GA ČR GA203/05/2106 Keywords : aqueous solubility * pressurized hot water * polycyclic aromatic compounds Subject RIV: CF - Physical ; Theoretical Chemistry

  18. Measurement of Aromatic-hydrocarbons With the DOAS Technique

    OpenAIRE

    Axelsson, H; Eilard, A.; Emanuelsson, A.; Galle, B.; Edner, Hans; Ragnarson, P; Kloo, H

    1995-01-01

    Long-path DOAS (differential optical absorption spectroscopy) in the ultraviolet spectral region has been shown to be applicable for low-concentration measurements of light aromatic hydrocarbons. However, because of spectral interferences among different aromatics as well as with oxygen, ozone, and sulfur dioxide, the application of the DOAS technique for this group of components is not without problems. This project includes a study of the differential absorption characteristics, between 250...

  19. DNA-Catalyzed Hydrolysis of Esters and Aromatic Amides

    OpenAIRE

    Brandsen, Benjamin M.; Hesser, Anthony R.; Castner, Marissa A.; Chandra, Madhavaiah; Silverman, Scott K.

    2013-01-01

    We previously reported that DNA catalysts (deoxyribozymes) can hydrolyze DNA phosphodiester linkages, but DNA-catalyzed amide bond hydrolysis has been elusive. Here we used in vitro selection to identify DNA catalysts that hydrolyze ester linkages as well as DNA catalysts that hydrolyze aromatic amides, for which the leaving group is an aniline moiety. The aromatic amide-hydrolyzing deoxyribozymes were examined using linear free energy relationship analysis. The hydrolysis reaction is unaffec...

  20. Terahertz Spectroscopy of Biochars and Related Aromatic Compounds

    Science.gov (United States)

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

    2016-07-01

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